Development and selection of T lymphocytes in the thymus, Organogenesis of the thymus, Biology of immune system development (immunity, T cells, T lymphocytes, thymus, cell differentiation)
Book / Paper
Book:
1.
Izumi Ohigashi, M Matsuda-Lennikov and Yousuke Takahama : Large-scale isolation of mouse thymic epithelial cells, Nov. 2022.
(Summary)
The thymus is compartmentalized into the cortex and the medulla. Cortical and medullary thymic epithelial cells (TECs) characterize T cell-producing and T cell-selecting functions of cortical and medullary microenvironments in the thymus. Enzymatic digestion of the thymus and flow cytometric isolation of TECs and their subpopulations are useful for molecular and cellular characterization of TECs. However, the cellularity of cTECs and mTECs isolated from mouse thymus is limited. In this chapter, we describe the method for isolation of a large number of TECs using enlarged mouse thymus, which enables biochemical and proteomic analysis of TEC subpopulations.
The chemokine CCL21 regulates immune and cancer cell migration through its receptor CCR7. The gene encodes the isoform CCL21-Ser, predominantly expressed in the thymic medulla and the secondary lymphoid tissues. This study examined the roles of CCL21-Ser in the antitumor immune response in -knockout (KO) mice. The KO mice showed significantly decreased growth of B16-F10 and YUMM1.7 melanomas and increased growth of MC38 colon cancer, despite no significant difference in LLC lung cancer and EO771 breast cancer. The B16-F10 tumor in -KO mice showed melanoma-specific activated CD8 T cell and NK cell infiltration and higher Treg counts than wild-type mice. B16-F10 tumors in -KO mice showed a reduction in the positive correlation between the ratio of regulatory T cells (Tregs) to activated CD8 T cells and tumor weight. In -KO tumor, the intratumoral Tregs showed lower co-inhibitory receptors TIM-3 and TIGIT. Taken together, these results suggest that endogenous CCL21-Ser supports melanoma growth by maintaining Treg function and suppressing antitumor immunity by CD8 T cells.
B Lucas, AJ White, F Klein, C Veiga-Villauriz, A Handel, A Bacon, EJ Cosway, KD James, SM Parnell, Izumi Ohigashi, Yousuke Takahama, WE Jenkinson, GA Hollander, WY Lu and G Anderson : Embryonic keratin19+ progenitors generate multiple functionally distinct progeny to maintain epithelial diversity in the adult thymus medulla, Nature Communications, Vol.14, No.1, 2066, 2023.
(Summary)
The thymus medulla is a key site for immunoregulation and tolerance, and its functional specialisation is achieved through the complexity of medullary thymic epithelial cells (mTEC). While the importance of the medulla for thymus function is clear, the production and maintenance of mTEC diversity remains poorly understood. Here, using ontogenetic and inducible fate-mapping approaches, we identify mTEC-restricted progenitors as a cytokeratin19 (K19) TEC subset that emerges in the embryonic thymus. Importantly, labelling of a single cohort of K19 TEC during embryogenesis sustains the production of multiple mTEC subsets into adulthood, including CCL21 mTEC, Aire mTEC and thymic tuft cells. We show K19 progenitors arise prior to the acquisition of multiple mTEC-defining features including RANK and CCL21 and are generated independently of the key mTEC regulator, Relb. In conclusion, we identify and define a multipotent mTEC progenitor that emerges during embryogenesis to support mTEC diversity into adult life.
Y Zhang, L Garcia-Ibanez, C Ulbricht, LSC Lok, JA Pike, J Mueller-Winkler, TW Dennison, JR Ferdinand, CJM Burnett, JC Yam-Puc, L Zhang, RM Alfaro, Yousuke Takahama, Izumi Ohigashi, G Brown, T Kurosaki, VLJ Tybulewicz, A Rot, AE Hauser, MR Clatworthy and KM Toellner : Recycling of memory B cells between germinal center and lymph node subcapsular sinus supports affinity maturation to antigenic drift, Nature Communications, Vol.13, No.1, 2460, 2022.
(Summary)
Infection or vaccination leads to the development of germinal centers (GC) where B cells evolve high affinity antigen receptors, eventually producing antibody-forming plasma cells or memory B cells. Here we follow the migratory pathways of B cells emerging from germinal centers (B) and find that many B cells migrate into the lymph node subcapsular sinus (SCS) guided by sphingosine-1-phosphate (S1P). From the SCS, B cells may exit the lymph node to enter distant tissues, while some B cells interact with and take up antigen from SCS macrophages, followed by CCL21-guided return towards the GC. Disruption of local CCL21 gradients inhibits the recycling of B cells and results in less efficient adaption to antigenic variation. Our findings thus suggest that the recycling of antigen variant-specific B cells and transport of antigen back to GC may support affinity maturation to antigenic drift.
(Keyword)
Antigenic Drift and Shift / B-Lymphocytes / Germinal Center / Lymph Nodes / Memory B Cells
Izumi Ohigashi and Yousuke Takahama : Specific impact of β5t on proteasome subunit composition in cortical thymic epithelial cells, Cell Reports, Vol.36, No.10, 109657, 2021.
(Summary)
β5t is a cortical thymic epithelial cell (cTEC)-specific component of the thymoproteasome, which is essential for the optimal production of functionally competent CD8 T cells. Our recent analysis showed a specific impact of β5t on proteasome subunit composition in cTECs, supporting the possibility that the thymoproteasome optimizes CD8 T cell development through the production of MHC-I-associated unique self-peptides in cTECs. However, a recent article reports that β5t regulates the expression of hundreds of cTEC genes and affects both CD4 and CD8 thymocytes by causing oxidative stress in thymocytes. The authors further analyze our published data and describe that they confirm their conclusions. Here, we examine the issues that they raise and conclude that, rather than regulating hundreds of genes in cTECs, β5t has a highly specific impact in cTECs on proteasome subunit composition. This Matters Arising Response article addresses the Apavaloaei et al. (2021) Matters Arising paper, published concurrently in Cell Reports.
(Keyword)
CD8-Positive T-Lymphocytes / Epithelial Cells / Histocompatibility Antigens Class I / Proteasome Endopeptidase Complex / Thymocytes
Izumi Ohigashi, Melina Frantzeskakis, Alison Jacques, Sayumi Fujimori, Aya Ushio, Fusano Yamashita, Naozumi Ishimaru, Da Yin, Margaret Cam, C Michael Kelly, Parirokh Awasthi, Kensuke Takada and Yousuke Takahama : The thymoproteasome hardwires the TCR repertoire of CD8+ T cells in the cortex independent of negative selection., The Journal of Experimental Medicine, Vol.218, No.4, 2021.
(Summary)
The thymoproteasome expressed specifically in thymic cortical epithelium optimizes the generation of CD8+ T cells; however, how the thymoproteasome contributes to CD8+ T cell development is unclear. Here, we show that the thymoproteasome shapes the TCR repertoire directly in cortical thymocytes before migration to the thymic medulla. We further show that the thymoproteasome optimizes CD8+ T cell production independent of the thymic medulla; independent of additional antigen-presenting cells, including medullary thymic epithelial cells and dendritic cells; and independent of apoptosis-mediated negative selection. These results indicate that the thymoproteasome hardwires the TCR repertoire of CD8+ T cells with cortical positive selection independent of negative selection in the thymus.
Ferreirinha Pedro, Ribeiro Camila, Junko Morimoto, Landry J M Jonathan, Minoru Matsumoto, Meireles Catarina, White J Andrea, Izumi Ohigashi, Araújo Leonor, Benes Vladimir, Yousuke Takahama, Anderson Graham, Mitsuru Matsumoto and Alves L Nuno : A novel method to identify Post-Aire stages of medullary thymic epithelial cell differentiation, European Journal of Immunology, Vol.51, No.2, 311-318, 2021.
(Summary)
Autoimmune regulator (Aire) medullary thymic epithelial cells (mTECs) play a critical role in tolerance induction. Several studies demonstrated that Aire mTECs differentiate further into Post-Aire cells. Yet, the identification of terminal stages of mTEC maturation depends on unique fate-mapping mouse models. Herein, we resolve this limitation by segmenting the mTEC (MHCII CD80 ) compartment into mTEC (CD24 Sca1 ), mTEC (CD24 Sca1 ), and mTEC (CD24 Sca1 ). While mTEC included mostly Aire-expressing cells, mTEC contained Aire and Aire cells and mTEC were mainly composed of cells lacking Aire. The differential expression pattern of Aire led us to investigate the precursor-product relationship between these subsets. Strikingly, transcriptomic analysis of mTEC , mTEC , and mTEC sequentially mirrored the specific genetic program of Early-, Late- and Post-Aire mTECs. Corroborating their Post-Aire nature, mTEC downregulated the expression of tissue-restricted antigens, acquired traits of differentiated keratinocytes, and were absent in Aire-deficient mice. Collectively, our findings reveal a new and simple blueprint to survey late stages of mTEC differentiation.
KD James, DF Legler, V Purvanov, Izumi Ohigashi, Yousuke Takahama, SM Parnell, AJ White, WE Jenkinson and G Anderson : Medullary stromal cells synergize their production and capture of CCL21 for T-cell emigration from neonatal mouse thymus, Blood Advances, Vol.5, No.1, 99-112, 2021.
JE Cowan, Yousuke Takahama, A Bhandoola and Izumi Ohigashi : Postnatal involution and counter-involution of the thymus. Frontiers in Immunology, Frontiers in Immunology, Vol.11, No.897, 2020.
(Summary)
Thymus involution occurs in all vertebrates. It is thought to impact on immune responses in the aged, and in other clinical circumstances such as bone marrow transplantation. Determinants of thymus growth and size are beginning to be identified. Ectopic expression of factors like cyclin D1 and Myc in thymic epithelial cells (TEC)s results in considerable increase in thymus size. These models provide useful experimental tools that allow thymus function to be understood. In future, understanding TEC-specific controllers of growth will provide new approaches to thymus regeneration.
B Lucas, AJ White, EJ Cosway, SM Parnell, KD James, ND Jones, Izumi Ohigashi, Yousuke Takahama, WE Jenkinson and G Anderson : Diversity in medullary thymic epithelial cells controls the activity and availability of iNKT cells, Nature Communications, Vol.11, No.1, 2020.
(Summary)
The thymus supports multiple αβ T cell lineages that are functionally distinct, but mechanisms that control this multifaceted development are poorly understood. Here we examine medullary thymic epithelial cell (mTEC) heterogeneity and its influence on CD1d-restricted iNKT cells. We find three distinct mTEC subsets distinguished by surface, intracellular and secreted molecules, and identify LTβR as a cell-autonomous controller of their development. Importantly, this mTEC heterogeneity enables the thymus to differentially control iNKT sublineages possessing distinct effector properties. mTEC expression of LTβR is essential for the development thymic tuft cells which regulate NKT2 via IL-25, while LTβR controls CD104CCL21 mTEC that are capable of IL-15-transpresentation for regulating NKT1 and NKT17. Finally, mTECs regulate both iNKT-mediated activation of thymic dendritic cells, and iNKT availability in extrathymic sites. In conclusion, mTEC specialization controls intrathymic iNKT cell development and function, and determines iNKT pool size in peripheral tissues.
Hiroyuki Kondo, Takafumi Matsumura, Mari Kaneko, Kenichi Inoue, Hidetaka Kosako, Masahito Ikawa, Yousuke Takahama and Izumi Ohigashi : PITHD1 is a proteasome-interacting protein essential for male fertilization, The Journal of Biological Chemistry, Vol.295, No.6, 1658-1672, 2020.
(Summary)
The proteasome is a protein-degrading molecular complex that is necessary for protein homeostasis and various biological functions, including cell cycle regulation, signal transduction, and immune response. Proteasome activity is finely regulated by a variety of proteasome-interacting molecules. PITHD1 is a recently described molecule that has a domain putatively capable of interacting with the proteasome. However, it is unknown whether PITHD1 can actually bind to proteasomes and what it does Here we report that PITHD1 is detected specifically in the spermatids in the testis and the cortical thymic epithelium in the thymus. Interestingly, PITHD1 associates with immunoproteasomes in the testis, but not with thymoproteasomes in the thymus. Mice deficient in PITHD1 exhibit severe male infertility accompanied with morphological abnormalities and impaired motility of spermatozoa. Furthermore, PITHD1 deficiency reduces proteasome activity in the testis and alters the amount of proteins that are important for fertilization capability by the sperm. However, the PITHD1-deficient mice demonstrate no detectable defects in the thymus, including T cell development. Collectively, our results identify PITHD1 as a proteasome-interacting protein that plays a nonredundant role in the male reproductive system.
Jennifer E. Cowan, Justin Malin, Yongge Zhao, Mina O. Seedhom, Christelle Harly, Izumi Ohigashi, Michael Kelly, Yousuke Takahama, Jonathan W. Yewdell, Maggie Cam and Avinash Bhandoola : Myc controls a distinct transcriptional program in fetal thymic epithelial cells that determines thymus growth, Nature Communications, Vol.10, No.1, 5498, 2019.
(Summary)
Interactions between thymic epithelial cells (TEC) and developing thymocytes are essential for T cell development, but molecular insights on TEC and thymus homeostasis are still lacking. Here we identify distinct transcriptional programs of TEC that account for their age-specific properties, including proliferation rates, engraftability and function. Further analyses identify Myc as a regulator of fetal thymus development to support the rapid increase of thymus size during fetal life. Enforced Myc expression in TEC induces the prolonged maintenance of a fetal-specific transcriptional program, which in turn extends the growth phase of the thymus and enhances thymic output; meanwhile, inducible expression of Myc in adult TEC similarly promotes thymic growth. Mechanistically, this Myc function is associated with enhanced ribosomal biogenesis in TEC. Our study thus identifies age-specific transcriptional programs in TEC, and establishes that Myc controls thymus size.
Shahina Umme Khanom, Izumi Ohigashi, Sayumi Fujimori, Kenta Kondou, Kensuke Takada and Yousuke Takahama : TCR affinity for in vivo peptide-induced thymic positive selection fine-tunes TCR responsiveness of peripheral CD8+ T cells, The Journal of Immunology, Vol.203, No.4, 881-887, 2019.
(Summary)
The affinity for TCR interactions with self-peptide/MHC complexes (pMHC) in the thymus critically affects immature thymocytes that newly express TCRs. Previous fetal thymus organ culture experiments have indicated that difference in the affinity for thymic TCR/pMHC interactions not only determines thymocyte fate between positive and negative selection, but also affects Ag responsiveness of positively selected thymocytes. In the current study, we examined whether TCR/pMHC affinity during positive selection in the thymus would further affect Ag responsiveness of mature T cells in the periphery. To do so, OVA peptide variants were in vivo administered to TAP1-deficient OT-I/TCR-transgenic mice in which T cell development was otherwise arrested at CD4CD8 thymocytes because of the lack of self-pMHC presentation in thymic APCs. We found that a group of peptide variants induced the transient generation of OT-I CD8 T cells in the thymus and the periphery. We also noticed that the affinity threshold for positive and negative selection detected in adult mice in vivo was higher than that measured in fetal thymus organ culture experiments in vitro. Interestingly, we further found that the affinity for positively selecting peptides proportionally affected TCR responsiveness of peripheral naive CD8 T cells. These results indicate that in vivo administration of a peptide can promote T cell selection in the thymus and the affinity for TCR/pMHC interaction during positive selection fine-tunes Ag responsiveness of peripheral T cells.
Emilie J. Cosway, Izumi Ohigashi, Karin Schauble, Sonia M. Parnell, William E. Jenkinson, Sanjiv Luther, Yousuke Takahama and Graham Anderson : Formation of the intrathymic dendritic cell pool requires CCL21-mediated recruitment of CCR7+ progenitors to the thymus, The Journal of Immunology, Vol.201, No.2, 516-523, 2018.
(Summary)
During αβ T cell development in the thymus, migration of newly selected CD4 and CD8 thymocytes into medullary areas enables tolerance mechanisms to purge the newly selected αβ TCR repertoire of autoreactive specificities. Thymic dendritic cells (DC) play key roles in this process and consist of three distinct subsets that differ in their developmental origins. Thus, plasmacytoid DC and Sirpα conventional DC type 2 are extrathymically derived and enter into the thymus via their respective expression of the chemokine receptors CCR9 and CCR2. In contrast, although Sirpα conventional DC type 1 (cDC1) are known to arise intrathymically from immature progenitors, the precise nature of such thymus-colonizing progenitors and the mechanisms controlling their thymus entry are unclear. In this article, we report a selective reduction in thymic cDC1 in mice lacking the chemokine receptor CCR7. In addition, we show that the thymus contains a CD11cMHC class IISirpαFlt3 cDC progenitor population that expresses CCR7, and that migration of these cells to the thymus is impaired in mice. Moreover, thymic cDC1 defects in mice are mirrored in mice, with further analysis of mice individually lacking the CCR7 ligands CCL21Ser ( ) or CCL19 ( demonstrating an essential role for CCR7-CCL21Ser during intrathymic cDC1 development. Collectively, our data support a mechanism in which CCR7-CCL21Ser interactions guide the migration of cDC progenitors to the thymus for correct formation of the intrathymic cDC1 pool.
Mie Sakata, Izumi Ohigashi and Yousuke Takahama : Cellularity of Thymic Epithelial Cells in the Postnatal Mouse., The Journal of Immunology, Vol.200, No.4, 1382-1388, 2018.
(Summary)
The molecular and cellular biology of thymic epithelial cells (TECs) often relies on the analysis of TECs isolated in enzymatically digested single-cell suspensions derived from mouse thymus. Many independent studies have reported that the estimated cellularity of total TECs isolated from one adult mouse is on the order of up to 10 However, these numbers appear extremely small given that the cellularity of total thymocytes exceeds 10 and that TECs play multiple roles in thymocyte development and repertoire formation. In the present study, we aimed to measure the numbers of β5t-expressing cortical TECs and Aire-expressing medullary TECs in postnatal mouse thymus in situ without enzymatic digestion. The numbers of these TECs were manually counted in individual thymic sections and were three-dimensionally summed throughout the entire thymic lobes. The results show that the cellularity of total TECs in one 5-wk-old female mouse exceeds 10, containing 9 × 10 β5t cortical TECs and 1.1 × 10 Aire medullary TECs. These results suggest that the use of conventional enzymatic digestion methods for the isolation of TECs may have resulted in the underestimation of the cellularity, and possibly the biology, of TECs.
Mina Kozai, Yuki Kubo, Tomoya Katakai, Hiroyuki Kondo, Hiroshi Kiyonari, Karin Schaeuble, Sanjiv A. Luther, Naozumi Ishimaru, Izumi Ohigashi and Yousuke Takahama : Essential role of CCL21 in establishment of central self-tolerance in T cells, The Journal of Experimental Medicine, Vol.214, No.7, 1925-1935, 2017.
(Summary)
The chemokine receptor CCR7 directs T cell relocation into and within lymphoid organs, including the migration of developing thymocytes into the thymic medulla. However, how three functional CCR7 ligands in mouse, CCL19, CCL21Ser, and CCL21Leu, divide their roles in immune organs is unclear. By producing mice specifically deficient in CCL21Ser, we show that CCL21Ser is essential for the accumulation of positively selected thymocytes in the thymic medulla. CCL21Ser-deficient mice were impaired in the medullary deletion of self-reactive thymocytes and developed autoimmune dacryoadenitis. T cell accumulation in the lymph nodes was also defective. These results indicate a nonredundant role of CCL21Ser in the establishment of self-tolerance in T cells in the thymic medulla, and reveal a functional inequality among CCR7 ligands in vivo.
Kenta Kondou, Kensuke Takada and Yousuke Takahama : Antigen processing and presentation in the thymus: implications for T cell repertoire selection., Current Opinion in Immunology, Vol.46, 53-57, 2017.
(Summary)
The processing and presentation of major histocompatibility complex (MHC)-associated antigens depend on the intracellular digestion of self- and nonself-proteins, the loading of digested peptides onto MHC molecules, and the traffic of peptide-MHC complexes to plasma membrane surface for display to interacting T cells. Recent studies have revealed unique machineries for antigen processing and presentation in thymic antigen-presenting cells that display self-antigens to developing thymocytes for the formation of functionally competent yet self-tolerant T cell repertoire. Here, we briefly summarize those machineries, focusing on the biology of cortical and medullary thymic epithelial cells.
Andrew Sornborger, Jie Li, Cullen Timmons, Floria Lupu, Jonathan Eggenschwiler, Yousuke Takahama and Nancy R. Manley : MiCASA is a new method for quantifying cellular organization., Nature Communications, Vol.8, 15619, 2017.
(Summary)
While many tools exist for identifying and quantifying individual cell types, few methods are available to assess the relationships between cell types in organs and tissues and how these relationships change during aging or disease states. We present a quantitative method for evaluating cellular organization, using the mouse thymus as a test organ. The thymus is the primary lymphoid organ responsible for generating T cells in vertebrates, and its proper structure and organization is essential for optimal function. Our method, Multitaper Circularly Averaged Spectral Analysis (MiCASA), identifies differences in the tissue-level organization with high sensitivity, including defining a novel type of phenotype by measuring variability as a specific parameter. MiCASA provides a novel and easily implemented quantitative tool for assessing cellular organization.
The Psmb11-encoded β5t subunit of the thymoproteasome, which is specifically expressed in cortical thymic epithelial cells (cTECs), is essential for the optimal positive selection of functionally competent CD8+ T cells in mice. Here, we report that a human genomic PSMB11 variation, which is detectable at an appreciable allele frequency in human populations, alters the β5t amino acid sequence that affects the processing of catalytically active β5t proteins. The introduction of this variation in the mouse genome revealed that the heterozygotes showed reduced β5t expression in cTECs and the homozygotes further exhibited reduction in the cellularity of CD8+ T cells. No severe health problems were noticed in many heterozygous and 5 homozygous human individuals. Long-term analysis of health status, particularly in the homozygotes, is expected to improve our understanding of the role of the thymoproteasome-dependent positive selection of CD8+ T cells in humans.
(Keyword)
thymus / thymoproteasome / single nucleotide polymorphism
Kensuke Takada, Kenta Kondou and Yousuke Takahama : Generation of Peptides That Promote Positive Selection in the Thymus, The Journal of Immunology, Vol.198, No.6, 2215-2222, 2017.
(Summary)
To establish an immunocompetent TCR repertoire that is useful yet harmless to the body, a de novo thymocyte repertoire generated through the rearrangement of genes that encode TCR is shaped in the thymus through positive and negative selection. The affinity between TCRs and self-peptides associated with MHC molecules determines the fate of developing thymocytes. Low-affinity TCR engagement with self-peptide-MHC complexes mediates positive selection, a process that primarily occurs in the thymic cortex. Massive efforts exerted by many laboratories have led to the characterization of peptides that can induce positive selection. Moreover, it is now evident that protein degradation machineries unique to cortical thymic epithelial cells play a crucial role in the production of MHC-associated self-peptides for inducing positive selection. This review summarizes current knowledge on positive selection-inducing self-peptides and Ag processing machineries in cortical thymic epithelial cells. Recent studies on the role of positive selection in the functional tuning of T cells are also discussed.
Uddin Myn Muhammad, Izumi Ohigashi, Ryo Motosugi, Tomomi Nakayama, Mie Sakata, Jun Hamazaki, Yasumasa Nishito, Immanuel Rode, Keiji Tanaka, Tatsuya Takemoto, Shigeo Murata and Yousuke Takahama : Foxn1-5t transcriptional axis controls CD8+ T-cell production in the thymus., Nature Communications, Vol.8, 14419, 2017.
(Summary)
The thymus is an organ that produces functionally competent T cells that protect us from pathogens and malignancies. Foxn1 is a transcription factor that is essential for thymus organogenesis; however, the direct target for Foxn1 to actuate thymic T-cell production is unknown. Here we show that a Foxn1-binding cis-regulatory element promotes the transcription of β5t, which has an essential role in cortical thymic epithelial cells to induce positive selection of functionally competent CD8(+) T cells. A point mutation in this genome element results in a defect in β5t expression and CD8(+) T-cell production in mice. The results reveal a Foxn1-β5t transcriptional axis that governs CD8(+) T-cell production in the thymus.
Izumi Ohigashi, Mina Kozai and Yousuke Takahama : Development and developmental potential of cortical thymic epithelial cells, Immunological Reviews, Vol.271, No.1, 10-22, 2016.
(Summary)
The thymic cortex provides a microenvironment for the development and positive selection of immature T cells. Cortical thymic epithelial cells (cTECs), which structurally and functionally support the thymic cortical microenvironment, originate from endodermal epithelial progenitors that arise in the third pharyngeal pouch. Recent studies have revealed that thymic epithelial progenitors pass through a stage where the cells express cTEC-associated molecules prior to lineage separation into cTECs and medullary TECs (mTECs). Here, we review the molecular signatures of cTECs and highlight the development and developmental potential of cTECs.
CE Mayer, S Zuklys, S Zhanybekova, Izumi Ohigashi, HY Teh, SN Sansom, N Shikama-Dorn, K Hafen, IC Macaulay, ME Deadman, CP Ponting, Yousuke Takahama and GA Hollander : Dynamic spatio-temporal contribution of single β5t+ cortical epithelial precursors to the thymus medulla, European Journal of Immunology, Vol.46, No.4, 846-856, 2016.
(Summary)
Intrathymic T-cell development is critically dependent on cortical and medullary thymic epithelial cells (TECs). Both epithelial subsets originate during early thymus organogenesis from progenitor cells that express the thymoproteasome subunit β5t, a typical feature of cortical TECs. Using in vivo lineage fate mapping, we demonstrate in mice that β5t(+) TEC progenitors give rise to the medullary TEC compartment early in life but significantly limit their contribution once the medulla has completely formed. Lineage-tracing studies at single cell resolution demonstrate for young mice that the postnatal medulla is expanded from individual β5t(+) cortical progenitors located at the cortico-medullary junction. These results therefore not only define a developmental window during which the expansion of medulla is efficiently enabled by progenitors resident in the thymic cortex, but also reveal the spatio-temporal dynamics that control the growth of the thymic medulla.
Izumi Ohigashi and Yousuke Takahama : Flow Cytometry Analysis of Thymic Epithelial Cells and Their Subpopulations, Methods in Molecular Biology, Vol.1323, 65-73, 2016.
(Summary)
The parenchyma of the thymus is compartmentalized into the cortex and the medulla, which are constructed by cortical thymic epithelial cells (cortical TECs, cTECs) and medullary thymic epithelial cells (mTECs), respectively. cTECs and mTECs essentially and differentially regulate the development and repertoire selection of T cells. Consequently, the biology of T cell development and selection includes the study of TECs in addition to the study of developing T cells and other hematopoietic cells including dendritic cells. In this chapter, we describe the methods for flow cytometric analysis and sorting of TECs and their subpopulations, including cTECs and mTECs.
Izumi Ohigashi, Saulius Zuklys, Mie Sakata, Carlos E. Mayer, Yoko Hamazaki, Nagahiro Minato, Georg A Hollander and Yousuke Takahama : Adult thymic medullary epithelium is maintained and regenerated by lineage-restricted cells rather than bipotent progenitors, Cell Reports, Vol.13, No.7, 1432-1443, 2015.
(Summary)
Medullary thymic epithelial cells (mTECs) play an essential role in establishing self-tolerance in T cells. mTECs originate from bipotent TEC progenitors that generate both mTECs and cortical TECs (cTECs), although mTEC-restricted progenitors also have been reported. Here, we report in vivo fate-mapping analysis of cells that transcribe β5t, a cTEC trait expressed in bipotent progenitors, during a given period in mice. We show that, in adult mice, most mTECs are derived from progenitors that transcribe β5t during embryogenesis and the neonatal period up to 1 week of age. The contribution of adult β5t(+) progenitors was minor even during injury-triggered regeneration. Our results further demonstrate that adult mTEC-restricted progenitors are derived from perinatal β5t(+) progenitors. These results indicate that the adult thymic medullary epithelium is maintained and regenerated by mTEC-lineage cells that pass beyond the bipotent stage during early ontogeny.
Kensuke Takada, Francois Van Laethem, Yan Xing, Kazuyuki Akane, Haruhiko Suzuki, Shigeo Murata, Keiji Tanaka, Stephen C Jameson, Alfred Singer and Yousuke Takahama : TCR affinity for thymoproteasome-dependent positively selecting peptides conditions antigen responsiveness in CD8+ T cells, Nature Immunology, Vol.16, No.10, 1069-1076, 2015.
(Summary)
In the thymus, low-affinity T cell antigen receptor (TCR) engagement facilitates positive selection of a useful T cell repertoire. Here we report that TCR responsiveness of mature CD8(+) T cells is fine tuned by their affinity for positively selecting peptides in the thymus and that optimal TCR responsiveness requires positive selection on major histocompatibility complex class I-associated peptides produced by the thymoproteasome, which is specifically expressed in the thymic cortical epithelium. Thymoproteasome-independent positive selection of monoclonal CD8(+) T cells results in aberrant TCR responsiveness, homeostatic maintenance and immune responses to infection. These results demonstrate a novel aspect of positive selection, in which TCR affinity for positively selecting peptides produced by thymic epithelium determines the subsequent antigen responsiveness of mature CD8(+) T cells in the periphery.
Several chemokines play important roles in recruiting the monocyte/macrophage lineage into adipose tissues. We previously found CCL19 was highly expressed in adipocytes cocultured with macrophages stimulated by endotoxin. This study aimed to evaluate the role of CCL19-CCR7 axis on obesity and insulin resistance. Serum CCL19 concentration was examined in obese model mice challenged by endotoxin. CCL19 receptor-null, Ccr7(-/-), mice and wild-type mice fed a high-fat diet or normal diet were used to investigate the role of CCL19 signals on obesity-associated inflammation. CCL19 protein was elevated in the sera of obese model mice challenged by endotoxin. Ccr7(-/-) mice were protected from diet-induced obesity and insulin resistance. The adipose tissue and liver expression of inflammatory genes of Ccr7(-/-) mice was much lower than in diet-induced obese mice. Ccr7(-/-) mice were protected from fatty liver and dyslipidemia and exhibited increased thermogenesis on high-fat feeding. CCL19 attracts activated dendritic cells (DC). The expression of the DC markers, CD11b and 11c, was not observed in the adipose tissues of Ccr7(-/-) mice fed a high-fat diet, which might be closely associated with the protection of these mice from obesity. The CCL19-CCR7 pathway associates with the development of high-fat-induced obesity and insulin resistance.
Katsuhiro Sasaki, Kensuke Takada, Yuki Ohte, Hiroyuki Kondo, Hiroyuki Sorimachi, Keiji Tanaka, Yousuke Takahama and Shigeo Murata : Thymoproteasomes produce unique peptide motifs for positive selection of CD8(+) T cells., Nature Communications, Vol.6, 7484, 2015.
(Summary)
Positive selection in the thymus provides low-affinity T-cell receptor (TCR) engagement to support the development of potentially useful self-major histocompatibility complex class I (MHC-I)-restricted T cells. Optimal positive selection of CD8(+) T cells requires cortical thymic epithelial cells that express 5t-containing thymoproteasomes (tCPs). However, how tCPs govern positive selection is unclear. Here we show that the tCPs produce unique cleavage motifs in digested peptides and in MHC-I-associated peptides. Interestingly, MHC-I-associated peptides carrying these tCP-dependent motifs are enriched with low-affinity TCR ligands that efficiently induce the positive selection of functionally competent CD8(+) T cells in antigen-specific TCR-transgenic models. These results suggest that tCPs contribute to the positive selection of CD8(+) T cells by preferentially producing low-affinity TCR ligand peptides.
Kensuke Takada and Yousuke Takahama : Positive-selection-inducing self-peptides displayed by cortical thymic epithelial cells., Advances in Immunology, Vol.125, 87-110, 2015.
(Summary)
A repertoire of antigen recognition specificities in mature T cell pool is formed by the selection during T cell development in the thymus. Positive selection is an essential process for the development of functionally competent T cells and is dependent on the interaction between T cell antigen receptors (TCRs) that newly generated thymocytes express and self-peptide-associated major histocompatibility complex (pMHC) molecules that cortical thymic epithelial cells (cTECs) express. Characterization of positive-selection-inducing peptides has revealed that the low-affinity TCR engagement by the positive-selection-inducing pMHC complexes initiates intracellular signals that induce the survival of immature thymocytes and their differentiation into mature T cells. Recent studies suggest unique mechanisms of antigen processing in cTECs for the production of positively selecting MHC-bound self-peptides.
L Nuno Alves, Yousuke Takahama, Izumi Ohigashi, R Ana Ribeiro, Song Baik, Graham Anderson and E William Jenkinson : Serial progression of cortical and medullary thymic epithelial microenvironments., European Journal of Immunology, Vol.44, No.1, 16-22, 2014.
(Summary)
Thymic epithelial cells (TECs) provide key instructive signals for T-cell differentiation. Thymic cortical (cTECs) and medullary (mTECs) epithelial cells constitute two functionally distinct microenvironments for T-cell development, which derive from a common bipotent TEC progenitor. While seminal studies have partially elucidated events downstream of bipotent TECs in relation to the emergence of mTECs and their progenitors, the control and timing of the emergence of the cTEC lineage, particularly in relation to that of mTEC progenitors, has remained elusive. In this review, we describe distinct models that explain cTEC/mTEC lineage divergence from common bipotent progenitors. In particular, we summarize recent studies in mice providing evidence that mTECs, including the auto-immune regulator(+) subset, derive from progenitors initially endowed with phenotypic properties typically associated with the cTEC lineage. These observations support a novel "serial progression" model of TEC development, in which progenitors serially acquire cTEC lineage markers, prior to their commitment to the mTEC differentiation pathway. Gaining a better understanding of the phenotypic properties of early stages in TEC progenitor development should help in determining the mechanisms regulating cTEC/mTEC lineage development, and in strategies aimed at thymus reconstitution involving TEC therapy.
Kensuke Takada, Izumi Ohigashi, Michiyuki Kasai, Hiroshi Nakase and Yousuke Takahama : Development and function of cortical thymic epithelial cells., Current Topics in Microbiology and Immunology, Vol.373, 1-17, 2014.
(Summary)
The thymic cortex provides a microenvironment that supports the generation and T cell antigen receptor (TCR)-mediated selection of CD4(+)CD8(+)TCR(+) thymocytes. Cortical thymic epithelial cells (cTECs) are the essential component that forms the architecture of the thymic cortex and induces the generation as well as the selection of newly generated T cells. Here we summarize current knowledge on the development, function, and heterogeneity of cTECs, focusing on the expression and function of 5t, a cTEC-specific subunit of the thymoproteasome.
Izumi Ohigashi and Yousuke Takahama : CCRL1 marks heterogeneity in cortical and medullary thymic epithelial cells., European Journal of Immunology, Vol.44, No.10, 2872-2875, 2014.
(Summary)
Cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells (mTECs), which play essential roles in the establishment of a functionally competent and self-tolerant repertoire of T cells, are derived from common thymic epithelial progenitor cells (pTECs). Recent findings indicate that mTECs are derived from cells that express molecules that are abundant in cTECs rather than mTECs, and provide fresh insight into the characteristics of pTECs and their diversification pathways into TEC subpopulations. In this issue of the European Journal of Immunology, Ribeiro et al. [Eur. J. Immunol. 2014. 44: 2918-2924] focus on CCRL1, an atypical chemokine receptor that is highly expressed by cTECs rather than mTECs, and show that CCRL1-expressing embryonic TECs can give rise to mTECs. Interestingly, Ribeiro et al. further report that a fraction of postnatal mTECs express CCRL1 at a low level, suggesting novel complexity in mTECs.
Togoo Khongorzul, Yousuke Takahama and Kensuke Takada : Alpha-smooth muscle actin expression identifies subpopulations of lymph node non-hematopoietic cells., Biochemical and Biophysical Research Communications, Vol.449, No.2, 241-247, 2014.
(Summary)
Significant attention has been given to the role played by non-hematopoietic cells in the immune organs, including the lymph nodes, in hopes of understanding the development, maintenance, and regulation of the immune system. However, the molecular and cellular characterization of non-hematopoietic cells is still in its infancy. Here we show that non-hematopoietic cells in mouse lymph nodes can be fractionated into previously unidentified subpopulations according to the transgenic reporter expression of alpha-smooth muscle actin (αSMA). αSMA(+) non-hematopoietic cells were predominantly detected in gp38(+)CD31(-) and gp38(-)CD31(-) cells. Molecular expression profiles suggest similarities between αSMA(+)gp38(+)CD31(-) and αSMA(-)gp38(+)CD31(-) subpopulations and dissimilarities between αSMA(+)gp38(-)CD31(-) and αSMA(-)gp38(-)CD31(-) subpopulations. The results indicate that αSMA is a useful marker for further understanding the molecular and cellular characteristics of non-hematopoietic cells in the lymph nodes.
Kouta Yano, Christine Carter, Naofumi Yoshida, Takaya Abe, Akiko Yamada, Takeshi Nitta, Naozumi Ishimaru, Kensuke Takada, W Geoffrey Butcher and Yousuke Takahama : Gimap3 and Gimap5 cooperate to maintain T-cell numbers in the mouse., European Journal of Immunology, Vol.44, No.2, 561-572, 2014.
(Summary)
Gimap3 (IAN4) and Gimap5 (IAN5) are highly homologous GTP-binding proteins of the Gimap family. Gimap3 and Gimap5, whose transcripts are abundant in mature lymphocytes, can associate with antiapoptotic Bcl-2 family proteins. While it is established that Gimap5 regulates T-cell survival, the in vivo role of Gimap3 is unclear. Here we report the preparation and characteristics of mouse strains lacking Gimap3 and/or Gimap5. We found that the number of T cells was markedly reduced in mice deficient in both Gimap3 and Gimap5. The defects in T-cell cellularity were more severe in mice lacking both Gimap3 and Gimap5 than in mice lacking only Gimap5. No defects in the cellularity of T cells were detected in mice lacking only Gimap3, whereas bone marrow cells from Gimap3-deficient mice showed reduced T-cell production in a competitive hematopoietic environment. Moreover, retroviral overexpression and short hairpin RNAs-mediated silencing of Gimap3 in bone marrow cells elevated and reduced, respectively, the number of T cells produced in irradiated mice. These results suggest that Gimap3 is a regulator of T-cell numbers in the mouse and that multiple Gimap family proteins cooperate to maintain T-cell survival.
Naoko Matsui, Izumi Ohigashi, Keijirou Tanaka, Mie Sakata, Takahiro Furukawa, Yasushi Nakagawa, Kazuya Kondo, Tetsuya Kitagawa, Sumimasa Yamashita, Yoshiko Nomura, Yousuke Takahama and Ryuji Kaji : Increased number of Hassall's corpuscles in myasthenia gravis patients with thymic hyperplasia., Journal of Neuroimmunology, Vol.269, No.1-2, 56-61, 2014.
(Summary)
The thymus is implicated as an organ that contributes to autoimmunity in myasthenia gravis (MG) patients. Hassall's corpuscles (HCs) are assumed to represent the terminally differentiated stage of medullary thymic epithelial cells (mTECs). By using multicolor immunohistofluorescence analysis, we examined HCs in thymuses that were therapeutically excised from MG (+) and MG (-) patients. We found that the number of HCs per unit area of the thymic medulla was significantly elevated in the thymuses of MG (+) patients with thymic hyperplasia. CCL21 expression increased in the hyperplastic MG thymuses. We speculate that the altered differentiation of mTECs is associated with the thymic hyperplasia and the onset of MG.
A Joy Williams, Jingjing Zhang, Hyein Jeon, Takeshi Nitta, Izumi Ohigashi, David Klug, J Michael Kruhlak, Baishakhi Choudhury, O Susan Sharrow, Larry Granger, Anthony Adams, A Michael Eckhaus, Rhiannon S Jenkinson, R Ellen Richie, E Ronald Gress, Yousuke Takahama and J Richard Hodes : Thymic medullary epithelium and thymocyte self-tolerance require cooperation between CD28-CD80/86 and CD40-CD40L costimulatory pathways., The Journal of Immunology, Vol.192, No.2, 630-640, 2014.
(Summary)
A critical process during thymic development of the T cell repertoire is the induction of self-tolerance. Tolerance in developing T cells is highly dependent on medullary thymic epithelial cells (mTEC), and mTEC development in turn requires signals from mature single-positive thymocytes, a bidirectional relationship termed thymus crosstalk. We show that CD28-CD80/86 and CD40-CD40L costimulatory interactions, which mediate negative selection and self-tolerance, upregulate expression of LT, LT, and receptor activator for NF-B in the thymus and are necessary for medullary development. Combined absence of CD28-CD80/86 and CD40-CD40L results in profound deficiency in mTEC development comparable to that observed in the absence of single-positive thymocytes. This requirement for costimulatory signaling is maintained even in a TCR transgenic model of high-affinity TCR-ligand interactions. CD4 thymocytes maturing in the altered thymic epithelial environment of CD40/CD80/86 knockout mice are highly autoreactive in vitro and are lethal in congenic adoptive transfer in vivo, demonstrating a critical role for these costimulatory pathways in self-tolerance as well as thymic epithelial development. These findings demonstrate that cooperativity between CD28-CD80/86 and CD40-CD40L pathways is required for normal medullary epithelium and for maintenance of self-tolerance in thymocyte development.
Rhiannon S Jenkinson, A Joy Williams, Hyein Jeon, Jingjing Zhang, Takeshi Nitta, Izumi Ohigashi, Michael Kruhlak, Saulius Zuklys, Susan Sharrow, Anthony Adams, Larry Granger, Yongwon Choi, Ulrich Siebenlist, A Gail Bishop, A Georg Hollander, Yousuke Takahama and J Richard Hodes : TRAF3 enforces the requirement for T cell cross-talk in thymic medullary epithelial development., Proceedings of the National Academy of Sciences of the United States of America, Vol.110, No.52, 21107-21112, 2013.
(Summary)
Induction of self-tolerance in developing T cells depends on medullary thymic epithelial cells (mTECs), whose development, in turn, requires signals from single-positive (SP) thymocytes. Thus, the absence of SP thymocytes in Tcra(-/-) mice results in a profound deficiency in mTECs. Here, we have probed the mechanism that underlies this requirement for cross-talk with thymocytes in medullary development. Previous studies have implicated nonclassical NF-B as a pathway important in the development of mTECs, because mice lacking RelB, NIK, or IKK, critical components of this pathway, have an almost complete absence of mTECs, with resulting autoimmune pathology. We therefore assessed the effect of selective deletion in TEC of TNF receptor-associated factor 3 (TRAF3), an inhibitor of nonclassical NF-B signaling. Deletion of TRAF3 in thymic epithelial cells allowed RelB-dependent development of normal numbers of AIRE-expressing mTECs in the complete absence of SP thymocytes. Thus, mTEC development can occur in the absence of cross-talk with SP thymocytes, and signals provided by SP T cells are needed to overcome TRAF3-imposed arrest in mTEC development mediated by inhibition of nonclassical NF-B. We further observed that TRAF3 deletion is also capable of overcoming all requirements for LTR and CD40, which are otherwise necessary for mTEC development, but is not sufficient to overcome the requirement for RANKL, indicating a role for RANKL that is distinct from the signals provided by SP thymocytes. We conclude that TRAF3 plays a central role in regulation of mTEC development by imposing requirements for SP T cells and costimulation-mediated cross-talk in generation of the medullary compartment.
Taisuke Nakayama, Hirotsugu Kurobe, Noriko Sugasawa, Hajime Kinoshita, Mayuko Higashida, Yuki Matsuoka, Yasushi Yoshida, Yoichiro Hirata, Mie Sakata, Mark Maxfield, Yousuke Takahama, Masataka Sata, Toshiaki Tamaki, Tetsuya Kitagawa and Shuhei Tomita : Role of macrophage-derived Hypoxia-Inducible Factor (HIF)-1 as a mediator of vascular remodeling, Cardiovascular Research, Vol.99, No.4, 705-715, 2013.
(Summary)
Excessive vascular remodelling leads to progression of a wide range of vasculopathies, and the immune response to intimal injuries is crucial in this process. This vascular remodelling occurs in the hypoxic microenvironment and is closely related to the immune system. Macrophages play a key role in immunological-cell-mediated arterial remodelling. In this study, we clarified the role of macrophage-derived hypoxia-inducible factor (HIF-1α) in vascular remodelling. Wire-induced femoral arterial injury was inflicted in mice lacking the macrophage-specific HIF-1α gene and in their wild-type counterparts. The mutant mice showed both suppressed wire-induced neointimal thickening and decreased infiltration of inflammatory cells in the adventitia, compared with wild-type mice. Studies to clarify the mechanism of restrained vascular remodelling in the mutant mice revealed decreased production of pro-inflammatory cytokines by the activated macrophages and suppressed macrophage migration activity in the mutant mice. Gene expressions of the HIF-1α-deficient macrophages positively correlated with the phenotypic profile of M2 macrophages and negatively correlated with that of M1 macrophages. Our results show that HIF-1α in macrophages plays a crucial role in promoting vascular inflammation and remodelling. As decreasing HIF-1α activity in macrophages may prevent the progression of vascular remodelling, HIF-1α may be a possible therapeutic target in vascular diseases.
L Jerrod Bryson, V Ann Griffith, Bernard Iii Hughes, Fumi Saito, Yousuke Takahama, R Ellen Richie and R Nancy Manley : Cell-autonomous defects in thymic epithelial cells disrupt endothelial-perivascular cell interactions in the mouse thymus., PLoS ONE, Vol.8, No.6, e65196, 2013.
(Summary)
The thymus is composed of multiple stromal elements comprising specialized stromal microenvironments responsible for the development of self-tolerant and self-restricted T cells. Here, we investigated the ontogeny and maturation of the thymic vasculature. We show that endothelial cells initially enter the thymus at E13.5, with PDGFR-(+) mesenchymal cells following at E14.5. Using an allelic series of the thymic epithelial cell (TEC) specific transcription factor Foxn1, we showed that these events are delayed by 1-2 days in Foxn1 (/) mice, and this phenotype was exacerbated with reduced Foxn1 dosage. At subsequent stages there were fewer capillaries, leaky blood vessels, disrupted endothelium - perivascular cell interactions, endothelial cell vacuolization, and an overall failure of vascular organization. The expression of both VEGF-A and PDGF-B, which are both primarily expressed in vasculature-associated mesenchyme or endothelium in the thymus, were reduced at E13.5 and E15.5 in Foxn1 (/) mice compared with controls. These data suggest that Foxn1 is required in TECs both to recruit endothelial cells and for endothelial cells to communicate with thymic mesenchyme, and for the differentiation of vascular-associated mesenchymal cells. These data show that Foxn1 function in TECs is required for normal thymus size and to generate the cellular and molecular environment needed for normal thymic vascularization. These data further demonstrate a novel TEC-mesenchyme-endothelial interaction required for proper fetal thymus organogenesis.
Izumi Ohigashi, Saulius Zuklys, Mie Sakata, E Carlos Mayer, Saule Zhanybekova, Shigeo Murata, Keiji Tanaka, A Georg Holländer and Yousuke Takahama : Aire-expressing thymic medullary epithelial cells originate from β5t-expressing progenitor cells., Proceedings of the National Academy of Sciences of the United States of America, Vol.110, No.24, 9885-9890, 2013.
(Summary)
The thymus provides multiple microenvironments that are essential for the development and repertoire selection of T lymphocytes. The thymic cortex induces the generation and positive selection of T lymphocytes, whereas the thymic medulla establishes self-tolerance among the positively selected T lymphocytes. Cortical thymic epithelial cells (cTECs) and medullary TECs (mTECs) constitute the major stromal cells that structurally form and functionally characterize the cortex and the medulla, respectively. cTECs and mTECs are both derived from the endodermal epithelium of the third pharyngeal pouch. However, the molecular and cellular characteristics of the progenitor cells for the distinct TEC lineages are unclear. Here we report the preparation and characterization of mice that express the recombinase Cre instead of 5t, a proteasome subunit that is abundant in cTECs and not detected in other cell types, including mTECs. By crossing 5t-Cre knock-in mice with loxP-dependent GFP reporter mice, we found that 5t-Cre-mediated recombination occurs specifically in TECs but not in any other cell types in the mouse. Surprisingly, in addition to cTECs, 5t-Cre-loxP-mediated GFP expression was detected in almost all mTECs. These results indicate that the majority of mTECs, including autoimmune regulator-expressing mTECs, are derived from 5t-expressing progenitor cells.
Enkhsaikhan Lkhagvasuren, Mie Sakata, Izumi Ohigashi and Yousuke Takahama : Lymphotoxin receptor regulates the development of CCL21-expressing subset of postnatal medullary thymic epithelial cells., The Journal of Immunology, Vol.190, No.10, 5110-5117, 2013.
(Summary)
Medullary thymic epithelial cells (mTECs) play a pivotal role in the establishment of self-tolerance in T cells by ectopically expressing various tissue-restricted self-Ags and by chemoattracting developing thymocytes. The nuclear protein Aire expressed by mTECs contributes to the promiscuous expression of self-Ags, whereas CCR7-ligand (CCR7L) chemokines expressed by mTECs are responsible for the attraction of positively selected thymocytes. It is known that lymphotoxin signals from the positively selected thymocytes preferentially promote the expression of CCR7L rather than Aire in postnatal mTECs. However, it is unknown how lymphotoxin signals differentially regulate the expression of CCR7L and Aire in mTECs and whether CCR7L-expressing mTECs and Aire-expressing mTECs are distinct populations. In this study, we show that the majority of postnatal mTECs that express CCL21, a CCR7L chemokine, represent an mTEC subpopulation distinct from the Aire-expressing mTEC subpopulation. Interestingly, the development of CCL21-expressing mTECs, but not Aire-expressing mTECs, is impaired in mice deficient in the lymphotoxin receptor. These results indicate that postnatal mTECs consist of heterogeneous subsets that differ in the expression of CCL21 and Aire, and that lymphotoxin receptor regulates the development of the CCL21-expressing subset rather than the Aire-expressing subset of postnatal mTECs.
Hirotsugu Kurobe, Takashi Tominaga, Mikio Sugano, Yasunobu Hayabuchi, Yoshiyasu Egawa, Yousuke Takahama and Tetsuya Kitagawa : Complete but not partial thymectomy in early infancy reduces T-cell-mediated immune response: three-year tracing study after pediatric cardiac surgery., Journal of Thoracic and Cardiovascular Surgery, Vol.145, No.3, 656-662, 2013.
(Summary)
The results revealed that complete thymectomy in early infancy reduces the number of circulating T cells and T-cell-mediated immune responses for at least 3 years, suggesting that the thymus should be at least partially preserved during surgery in early infancy to maintain protective immunity.
(Keyword)
Female / Heart Defects, Congenital / Humans / Immunity, Cellular / Immunoglobulin G / Infant / Infant, Newborn / Male / Measles-Mumps-Rubella Vaccine / Severity of Illness Index / T-Lymphocytes / Thymectomy / Thymus Gland
Takeshi Nitta, Izumi Ohigashi and Yousuke Takahama : The development of T lymphocytes in fetal thymus organ culture., Methods in Molecular Biology, Vol.946, 85-102, 2013.
(Summary)
Fetal thymus organ culture (FTOC) is a unique and powerful culture system that allows intrathymic T-lymphocyte development in vitro. T-cell development in FTOC well represents fetal thymocyte development in vivo. Here we describe the basic method for FTOC as well as several related techniques, including reconstitution of thymus lobes with T-lymphoid progenitor cells, high-oxygen submersion culture, reaggregation thymus organ culture, retrovirus-mediated gene transfer to developing thymocytes in FTOC, and coculture of progenitor cells with OP9-DL1 cells.
Yasushi Nakagawa, Ohigashi Izumi, Nitta Takeshi, Sakata Mie, Tanaka Keiji, Murata Shigeo, Kanagawa Osami and Yousuke Takahama : Thymic nurse cells provide microenvironment for secondary T cell receptor rearrangement in cortical thymocytes, Proceedings of the National Academy of Sciences of the United States of America, Vol.109, No.50, 20572-20577, 2012.
(Summary)
Distinct subsets of thymic epithelial cells (TECs) support T-cell development and selection. Isolated TECs contain multicellular complexes that enclose many viable thymocytes. However, the functions of those TECs, termed thymic nurse cells (TNCs), are unclear and the idea that TNCs are present in vivo is questioned. Here, we show that TNCs represent a fraction of cortical (c)TECs that are defined by the expression of thymoproteasomes. Intravital imaging revealed TNCs in the thymic cortex in situ, whereas TNCs were detected neither during embryogenesis nor in the postnatal thymuses of various "positive-selector" T-cell receptor (TCR)-transgenic mice, indicating that TNCs are not essential for T-cell differentiation, including positive selection. Rather, cells within TNCs were enriched for long-lived CD4(+)CD8(+) thymocytes that underwent secondary TCR-Vα rearrangement. Thus, TNC complexes are formed in vivo by persistent cTEC-thymocyte interactions that then provide a microenvironment that optimizes T-cell selection through secondary TCR rearrangement.
Saulius Zuklys, E Carlos Mayer, Saule Zhanybekova, E Heather Stefanski, Gretel Nusspaumer, Jason Gill, Thomas Barthlott, Stephane Chappaz, Takeshi Nitta, James Dooley, Ruben Nogales-Cadenas, Yousuke Takahama, Daniela Finke, Adrian Liston, R Bruce Blazar, Alberto Pascual-Montano and A Georg Holländer : MicroRNAs control the maintenance of thymic epithelia and their competence for T lineage commitment and thymocyte selection., The Journal of Immunology, Vol.189, No.8, 3894-3904, 2012.
(Summary)
Thymic epithelial cells provide unique cues for the lifelong selection and differentiation of a repertoire of functionally diverse T cells. Rendered microRNA (miRNA) deficient, these stromal cells in the mouse lose their capacity to instruct the commitment of hematopoietic precursors to a T cell fate, to effect thymocyte positive selection, and to achieve promiscuous gene expression required for central tolerance induction. Over time, the microenvironment created by miRNA-deficient thymic epithelia assumes the cellular composition and structure of peripheral lymphoid tissue, where thympoiesis fails to be supported. These findings emphasize a global role for miRNA in the maintenance and function of the thymic epithelial cell scaffold and establish a novel mechanism how these cells control peripheral tissue Ag expression to prompt central immunological tolerance.
Graham Anderson and Yousuke Takahama : Thymic epithelial cells: working class heroes for T cell development and repertoire selection, Trends in Immunology, Vol.33, No.6, 256-263, 2012.
(Summary)
The thymus represents an epithelial-mesenchymal tissue, anatomically structured into discrete cortical and medullary regions that contain phenotypically and functionally distinct stromal cells, as well as thymocytes at defined stages of maturation. The stepwise progression of thymocyte development seems to require serial migration through these distinct thymic regions, where interactions with cortical thymic epithelial cell (cTEC) and medullary thymic epithelial cell (mTEC) subsets take place. Recent work on TEC subsets provides insight into T cell development and selection, such as the importance of tumour necrosis factor (TNF) receptor superfamily members in thymus medulla development, and the specialised antigen processing/presentation capacity of the thymic cortex for positive selection. Here, we summarise current knowledge on the development and function of the thymic microenvironment, paying particular attention to the cortical and medullary epithelial compartments.
NM Roberts, AJ White, WE Jenkinson, G Turchinovich, K Nakamura, DR Withers, FM McConnell, GE Desanti, C Benezech, SM Parnell, AF Cunningham, M Paolino, J Penninger, K Simon, T Nitta, Izumi Ohigashi, Yousuke Takahama, JH Caamano, AC Hayday, PJ Lane, EJ Jenkinson and G Anderson : Rank signaling links the development of invariant γδ T cell progenitors and Aire+ medullary epithelium., Immunity, Vol.36, No.3, 427-437, 2012.
(Summary)
The thymic medulla provides a specialized microenvironment for the negative selection of T cells, with the presence of autoimmune regulator (Aire)-expressing medullary thymic epithelial cells (mTECs) during the embryonic-neonatal period being both necessary and sufficient to establish long-lasting tolerance. Here we showed that emergence of the first cohorts of Aire(+) mTECs at this key developmental stage, prior to αβ T cell repertoire selection, was jointly directed by Rankl(+) lymphoid tissue inducer cells and invariant Vγ5(+) dendritic epidermal T cell (DETC) progenitors that are the first thymocytes to express the products of gene rearrangement. In turn, generation of Aire(+) mTECs then fostered Skint-1-dependent, but Aire-independent, DETC progenitor maturation and the emergence of an invariant DETC repertoire. Hence, our data attributed a functional importance to the temporal development of Vγ5(+) γδ T cells during thymus medulla formation for αβ T cell tolerance induction and demonstrated a Rank-mediated reciprocal link between DETC and Aire(+) mTEC maturation.
Yu Lei and Yousuke Takahama : XCL1 and XCR1 in the immune system, Microbes and Infection, Vol.14, No.3, 262-267, 2012.
(Summary)
XCL1, a C class chemokine also known as lymphotactin, is produced by T, NK, and NKT cells during infectious and inflammatory responses, whereas XCR1, the receptor of XCL1, is expressed by a dendritic cell subpopulation. The XCL1-XCR1 axis plays an important role in dendritic-cell-mediated cytotoxic immune response. It has been also shown that XCL1 and XCR1 are constitutively expressed in the thymus and regulate the thymic establishment of self-tolerance and the generation of regulatory T cells. This review summarizes the expression and function of XCL1 and XCR1 in the immune system.
Yousuke Takahama, Kensuke Takada, Shigeo Murata and Keiji Tanaka : Beta5t-containing thymoproteasome: specific expression in thymic cortical epithelial cells and role in positive selection of CD8+ T cells., Current Opinion in Immunology, Vol.24, No.1, 92-98, 2012.
(Summary)
Proteasomes are multisubunit proteolytic complexes that degrade cytoplasmic and nuclear proteins in eukaryotes. Proteasome-dependent proteolysis contributes to various cellular processes, including misfolded protein degradation, signal transduction, and antigen presentation. The thymoproteasome is a form of proteasome that contains the vertebrate-specific catalytic subunit β5t specifically expressed by cortical epithelial cells in the thymus. The thymoproteasome is essential for the positive selection of CD8+ T cells that carry an immunocompetent repertoire of antigen recognition specificity. Here we summarize the structure and expression of the thymoproteasome and discuss how it regulates the positive selection of CD8+ T cells.
Naozumi Ishimaru, Akiko Yamada, Takeshi Nitta, Rieko Arakaki, Martin Lipp, Yousuke Takahama and Yoshio Hayashi : CCR7 with S1P1 signaling through AP-1 for migration of Foxp3+ regulatory T-cells controls autoimmune exocrinopathy., The American Journal of Pathology, Vol.180, No.1, 199-208, 2012.
(Summary)
Forkhead box p3-positive (Foxp3(+)) regulatory T cells (T(reg) cells) participate in maintaining peripheral immune tolerance and suppressing autoimmunity. We recently reported that in situ patrolling by C-C-chemokine receptor 7 (CCR7)(+) T(reg) cells in target organs is essential for controlling autoimmune lesions in Sjögren's syndrome. In the present study, the molecular mechanism underlying CCR7-mediated T(reg) cell migration was investigated in a mouse model. The impaired migratory response of Ccr7(-/-) T(reg) cells to sphingosine 1-phosphate (S1P) occurred because of defective association of S1P receptor 1 (S1P(1)) with a G coupled-protein. In addition, T-cell receptor (TCR)- and S1P(1)-mediated Ras-related C3 botulinum toxin substrate 1 (Rac-1), extracellular signal-related kinase (ERK), and c-Jun phosphorylation required for activator protein 1 (AP-1) transcriptional activity were significantly impaired in Ccr7(-/-) T(reg) cells. Surprisingly, the abnormal nuclear localization of Foxp3 was detected after abrogation of the c-Jun and Foxp3 interaction in the nucleus of Ccr7(-/-) T(reg) cells. These results indicate that CCR7 essentially controls the migratory function of T(reg) cells through S1P(1)-mediated AP-1 signaling, which is regulated through its interaction with Foxp3 in the nucleus.
Izumi Ohigashi, Takeshi Nitta, E Lkhagvasuren, H Yasuda and Yousuke Takahama : Effects of RANKL on the thymic medulla, European Journal of Immunology, Vol.41, No.7, 1822-1827, 2011.
(Summary)
The thymic medulla provides a microenvironment where medullary thymic epithelial cells (mTECs) contribute to the establishment of self-tolerance by the deletion of self-reactive T cells and the generation of regulatory T cells. The progression of thymocyte development critically regulates the optimum formation of the thymic medulla, as discussed in this article. Of note, it was recently identified that RANKL produced by positively selected thymocytes plays a major role in the thymocyte-mediated medulla formation. Indeed, transgenic expression of soluble RANKL increased the number of mTECs and enlarged the thymic medulla in mice. The effects of RANKL on the thymic medulla may be useful for the engineering of self-tolerance in T cells.
A Ripen Mat, Takeshi Nitta, S Murata, K Tanaka and Yousuke Takahama : Ontogeny of thymic cortical epithelial cells expressing the thymoproteasome subunit β5t, European Journal of Immunology, Vol.41, No.5, 1278-1287, 2011.
(Summary)
Proteasomes are responsible for generating peptides presented by class I MHC molecules of the immune system. β5t, a recently identified proteasome component, is specifically expressed in thymic cortical epithelial cells (cTECs) and plays a pivotal role in generating an immunocompetent repertoire of class I MHC-restricted CD8(+) T cells. Here, we report that β5t is detectable in the thymus as early as E12.5 mouse embryos. We also found that β5t expression in cTECs was detectable in mice deficient for RelB or Rag2, indicating that β5t in cTECs is expressed in the absence of thymic medulla formation or thymocyte development beyond the CD4(-) CD8(-) stage. β5t expression in the embryonic thymus was not detectable in Foxn1-deficient nude mice, although its expression was not reduced in mice deficient for both CCR7 and CCR9, in which fetal thymus colonization by leukocytes is defective. These results indicate that β5t expression in cTECs is dependent on Foxn1 but independent of thymocyte crosstalk or thymic medulla formation.
Yu Lei, Adiratna Mat Ripen, Naozumi Ishimaru, Izumi Ohigashi, Takashi Nagasawa, Lukas T. Jeker, Michael R. Bösl, Georg A. Holländer, Yoshio Hayashi, Rene Waal de Malefyt, Takeshi Nitta and Yousuke Takahama : Aire-dependent production of XCL1 mediates medullary accumulation of thymic dendritic cells and contributes to regulatory T cell development, The Journal of Experimental Medicine, Vol.208, No.2, 383-394, 2011.
(Summary)
Dendritic cells (DCs) in the thymus (tDCs) are predominantly accumulated in the medulla and contribute to the establishment of self-tolerance. However, how the medullary accumulation of tDCs is regulated and involved in self-tolerance is unclear. We show that the chemokine receptor XCR1 is expressed by tDCs, whereas medullary thymic epithelial cells (mTECs) express the ligand XCL1. XCL1-deficient mice are defective in the medullary accumulation of tDCs and the thymic generation of naturally occurring regulatory T cells (nT reg cells). Thymocytes from XCL1-deficient mice elicit dacryoadenitis in nude mice. mTEC expression of XCL1, tDC medullary accumulation, and nT reg cell generation are diminished in Aire-deficient mice. These results indicate that the XCL1-mediated medullary accumulation of tDCs contributes to nT reg cell development and is regulated by Aire.
Takeshi Nitta, Izumi Ohigashi, Yasushi Nakagawa and Yousuke Takahama : Cytokine crosstalk for thymic medulla formation, Current Opinion in Immunology, Vol.23, No.2, 190-197, 2011.
(Summary)
The medullary microenvironment of the thymus plays a crucial role in the establishment of self-tolerance through the deletion of self-reactive thymocytes and the generation of regulatory T cells. Crosstalk or bidirectional signal exchanges between developing thymocytes and medullary thymic epithelial cells (mTECs) contribute to the formation of the thymic medulla. Recent studies have identified the molecules that mediate thymic crosstalk. Tumor necrosis factor superfamily cytokines, including RANKL, CD40L, and lymphotoxin, produced by positively selected thymocytes and lymphoid tissue inducer cells promote the proliferation and differentiation of mTECs. In return, CCR7 ligand chemokines produced by mTECs facilitate the migration of positively selected thymocytes to the medulla. The cytokine crosstalk between developing thymocytes and mTECs nurtures the formation of the thymic medulla and thereby regulates the establishment of self-tolerance.
Izumi Ohigashi, Yuki Yamasaki, Tsukasa Hirashima and Yousuke Takahama : Identification of the Transgenic Integration Site in Immunodeficient tgϵ26 Human CD3ϵ Transgenic Mice, PLoS ONE, Vol.5, No.12, e14391, 2010.
(Summary)
A strain of human CD3ϵ transgenic mice, tgϵ26, exhibits severe immunodeficiency associated with early arrest of T cell development. Complete loss of T cells is observed in homozygous tgϵ26 mice, but not in heterozygotes, suggesting that genomic disruption due to transgenic integration may contribute to the arrest of T cell development. Here we report the identification of the transgenic integration site in tgϵ26 mice. We found that multiple copies of the human CD3ϵ transgene are inserted between the Sstr5 and Metrn loci on chromosome 17, and that this is accompanied by duplication of the neighboring genomic region spanning 323 kb. However, none of the genes in this region were abrogated. These results suggest that the severe immunodeficiency seen in tgϵ26 mice is not due to gene disruption resulting from transgenic integration.
Kyoko Hidaka, Takeshi Nitta, Ryo Sugawa, J Robert Schwartz, Takashi Amagai, Sachiko Nitta, Yousuke Takahama and Takayuki Morisaki : Differentiation of Pharyngeal Endoderm and Derivatives from Mouse Embryonic Stem Cells., Stem Cells and Development, Vol.19, No.11, 1735-1743, 2010.
(Summary)
Embryonic stem cells are considered to be a good in vitro tool to study the induction of various cell types including cardiomyocytes; however, induction of the pharyngeal endoderm (PE), the underlying heart-forming region, in vivo has been scarcely reported. In the present study, we found that many PE-related genes, such as Paxl, Pax9, Sixl, and Tbxl, were up-regulated in cardiomyocyte-rich embryoid bodies (EBs). The third pouch-related genes including Hoxa3, Foxn1, and Aire, which are crucial for thymus development and function, were also detected in later stages. Nkx2.5, a cardiac transcription factor gene, is known to be transiently expressed in the PE. By crossing Nkx2.5-Cre mice with Cre-dependent EGFP reporter mice, we found that Nkx2.5(+) lineage exclusively contributed to thymic epithelial cell development, followed by thymus development. Gene expression analysis using Nkx2.5-EGFP ES cells also revealed that PE-related mRNAs were specifically enriched in the transiently appearing E-cadherin(+)Nkx2.5(+) cell fraction. Interestingly, the EB-derived cells were found capable of supporting T-cell differentiation to CD4 or CD8 double-positive cells in a reaggregation organ culture in vitro. Our results suggest that EBs contain cells that resemble third pharyngeal pouch endoderm and confer a thymus-like microenvironment.
Andrea J. White, Kyoko Nakamura, William E. Jenkinson, Manoj Saini, Charles Sinclair, Benedict Seddon, Parth Narendran, Klaus Pfeffer, Takeshi Nitta, Yousuke Takahama, Jorge H. Caamano, Peter J. L. Lane, Eric J. Jenkinson and Graham Anderson : Lymphotoxin signals from positively selected thymocytes regulate the terminal differentiation of medullary thymic epithelial cells, The Journal of Immunology, Vol.185, No.8, 4769-4776, 2010.
(Summary)
The thymic medulla represents a key site for the induction of T cell tolerance. In particular, autoimmune regulator (Aire)-expressing medullary thymic epithelial cells (mTECs) provide a spectrum of tissue-restricted Ags that, through both direct presentation and cross-presentation by dendritic cells, purge the developing T cell repertoire of autoimmune specificities. Despite this role, the mechanisms of Aire(+) mTEC development remain unclear, particularly those stages that occur post-Aire expression and represent mTEC terminal differentiation. In this study, in mouse thymus, we analyze late-stage mTEC development in relation to the timing and requirements for Aire and involucrin expression, the latter a marker of terminally differentiated epithelium including Hassall's corpuscles. We show that Aire expression and terminal differentiation within the mTEC lineage are temporally separable events that are controlled by distinct mechanisms. We find that whereas mature thymocytes are not essential for Aire(+) mTEC development, use of an inducible ZAP70 transgenic mouse line--in which positive selection can be temporally controlled--demonstrates that the emergence of involucrin(+) mTECs critically depends upon the presence of mature single positive thymocytes. Finally, although initial formation of Aire(+) mTECs depends upon RANK signaling, continued mTEC development to the involucrin(+) stage maps to activation of the LTα-LTβR axis by mature thymocytes. Collectively, our results reveal further complexity in the mechanisms regulating thymus medulla development and highlight the role of distinct TNFRs in initial and terminal differentiation stages in mTECs.
Yousuke Takahama, Takeshi Nitta, Adiratna MatRipen, Sachiko Nitta, Shigeo Murata and Keiji Tanaka : Role of thymic-cortex-specific self-peptides in positive selection of T cells., Seminars in Immunology, Vol.22, No.5, 287-293, 2010.
(Summary)
During T cell development in the thymus, a virgin repertoire of diverse TCRalphabeta recognition specificities in immature thymocytes is selected through positive and negative selection to form an immunocompetent and self-tolerant repertoire of mature T cells. Positive selection supports the survival of thymocytes that receive weak signals of low-avidity TCR engagement, whereas negative selection deletes potentially harmful self-reactive thymocytes upon high-avidity TCR engagement. Early studies have highlighted the role of TCR interaction with polymorphic MHC determinants in positive selection, while negative selection imposes TCR specificity to peptide antigens displayed by MHC molecules. However, recent advances in the biology of thymic stromal cells have indicated that the formation of an immunocompetent TCR repertoire requires positive selection by thymic cortical epithelial cells expressing a unique protein degradation machinery, suggesting the role of self-peptide repertoire specifically expressed by thymic cortical epithelial cells in the development of the acquired immune system.
Noriko Tosa, Atsushi Iwai, Taku Tanaka, Tomoka Kumagai, Takeshi Nitta, Satoko Chiba, Masahiro Maeda, Yousuke Takahama, Toshimitsu Uede and Tadaaki Miyazaki : Critical function of death-associated protein 3 in T cell receptor-mediated apoptosis induction., Biochemical and Biophysical Research Communications, Vol.395, No.3, 356-360, 2010.
(Summary)
Death-associated protein 3 (DAP3) is crucial for promoting apoptosis induced by various stimulations. This report demonstrates that DAP3 is also important for T cell receptor (TCR)-mediated apoptosis induction in immature thymocytes. Enforced expression of DAP3 accelerated the negative selection in developing thymocytes, using the reaggregate thymus organ culture system. In addition, expression of DAP3 accelerated TCR-mediated apoptosis induction in DO11.10 cells. We also demonstrated that DAP3 translocates into the nucleus during TCR-mediated apoptosis in a Nur77 dependent manner. It is concluded that DAP3 is critical for TCR-mediated induction of apoptosis at the downstream of Nur77.
(Keyword)
Active Transport, Cell Nucleus / Animals / apoptosis / Cell Nucleus / Mice / Nuclear Receptor Subfamily 4, Group A, Member 1 / Proteins / Receptors, Antigen, T-Cell
Naoko Matsui, Shunya Nakane, Fumi Saitou, Izumi Ohigashi, Yasushi Nakagawa, Hirotsugu Kurobe, Hiromitsu Takizawa, Takao Mitsui, Kazuya Kondo, Tetsuya Kitagawa, Yousuke Takahama and Ryuji Kaji : Undiminished regulatory T cells in the thymus of myathenia gravis patients, Neurology, Vol.74, No.10, 816-820, 2010.
(Summary)
The thymus has been implicated as a possible site of origin that triggers autoimmunity in myasthenia gravis (MG). Although several groups have suggested that the decrease in the number of regulatory T (Treg) cells contributes to the onset of MG, the exact role of Treg cells in MG remains unclear. To address this point, we examined the number and distribution of Treg cells in a large number of patients with MG. Immunohistofluorescence analysis of Foxp3 along with CD4 and CD8 was performed in thymic sections of MG (+) (n = 24) and MG (-) patients (n = 27). Circulating CD4(+)CD25(+) cells in the peripheral blood of patients with MG (n = 15) and age-matched healthy subjects (n = 15) were also analyzed. Foxp3(+)CD4(+)CD8(-) cells were predominantly found in the thymic medulla and their number declined with age. There was no significant difference in the number or the distribution of Foxp3(+)CD4(+)CD8(-) cells in the thymus between MG (+) and MG (-) patients. The number of circulating CD4(+)CD25(+) cells in the peripheral blood of patients with MG was not significantly altered compared to that in healthy subjects. The cellularity of Treg cells in the thymus and circulation is not diminished in patients with myasthenia gravis.
(Keyword)
Age Factors / Antigens, CD / Cell Count / Female / Flow Cytometry / Forkhead Transcription Factors / Humans / Male / Myasthenia Gravis / T-Lymphocytes, Regulatory / Thymus Gland
Hirotsugu Kurobe, Masahisa Urata, Masaki Ueno, Masaaki Ueki, Shiro Ono, Yuki Izawa-Ishizawa, Yayoi Fukuhara, Yu Lei, Adiratna Mat Ripen, Tamotsu Kanbara, Ken-ichi Aihara, Keisuke Ishizawa, Masashi Akaike, Frank J. Gonzalez, Toshiaki Tamaki, Yousuke Takahama, Masanori Yoshizumi, Tetsuya Kitagawa and Shuhei Tomita : Role of Hypoxia-Inducible Factor 1α in T Cells as a Negative Regulator in Development of Vascular Remodeling, Arteriosclerosis, Thrombosis, and Vascular Biology, Vol.30, No.2, 210-217, 2010.
(Summary)
Recent studies have shown that the cellular immune response in the development of vascular remodeling modulates the resulting pathological alterations. We show that hypoxia-inducible factor 1 (Hif-1) (specifically expressed in T cells) is involved in the immune response to vascular remodeling that accompanies arteriosclerosis. To study the role of T cells in the development of vascular remodeling, femoral arterial injury induced by an external vascular polyethylene cuff was examined in mice lacking Hif-1 (specifically in T cells). We found that cuff placement caused prominent neointimal hyperplasia of the femoral artery in Hif-1- (T-cell)-deficient mice compared with that in control mice and that infiltration of inflammatory cells at the adventitia was markedly increased in the mutant mice. Studies to clarify the mechanism of augmented vascular remodeling in the mutant mice showed enhanced production of cytokines by activated T cells and augmented antibody production in response to a T-dependent antigen in the mutant mice. The results of this study revealed that Hif-1alpha in T cells plays a crucial role in vascular inflammation and remodeling in response to cuff injury as a negative regulator of T cell-mediated immune response. Potential new therapeutic strategies that target Hif-1alpha are described.
Naozumi Ishimaru, Takeshi Nitta, Rieko Arakaki, Akiko Yamada, Martin Lipp, Yousuke Takahama and Yoshio Hayashi : In situ Patrolling of Regulatory T cells is Essential for Protecting Autoimmune Exocrinopathy, PLoS ONE, Vol.5, No.1, e8588, 2010.
(Summary)
Migration of T cells, including regulatory T (Treg) cells, into the secondary lymph organs is critically controlled by chemokines and adhesion molecules. However, the mechanisms by which Treg cells regulate organ-specific autoimmunity via these molecules remain unclear. Although we previously reported autoimmune exocrinopathy resembling Sjögren's syndrome (SS) in the lacrimal and salivary glands from C-C chemokine receptor 7 (CCR7)-deficient mice, it is still unclear whether CCR7 signaling might specifically affect the dynamics and functions of Treg cells in vivo. We therefore investigated the cellular mechanism for suppressive function of Treg cells via CCR7 in autoimmunity using mouse models and human samples. Patrolling Treg cells were detected in the exocrine organs such as lacrimal and salivary glands from normal mice that tend to be targets for autoimmunity while the Treg cells were almost undetectable in the exocrine glands of CCR7(-/-) mice. In addition, we found the significantly increased retention of CD4(+)CD25(+)Foxp3(+) Treg cells in the lymph nodes of CCR7(-/-) mice with aging. Although Treg cell egress requires sphingosine 1-phosphate (S1P), chemotactic function to S1P of CCR7-/- Treg cells was impaired compared with that of WT Treg cells. Moreover, the in vivo suppression activity was remarkably diminished in CCR7(-/-) Treg cells in the model where Treg cells were co-transferred with CCR7(-/-) CD25(-)CD4(+) T cells into Rag2(-/-) mice. Finally, confocal analysis showed that CCR7(+)Treg cells were detectable in normal salivary glands while the number of CCR7(+)Treg cells was extremely decreased in the tissues from patients with Sjögren's syndrome. These results indicate that CCR7 essentially governs the patrolling functions of Treg cells by controlling the traffic to the exocrine organs for protecting autoimmunity. Characterization of this cellular mechanism could have clinical implications by supporting development of new diagnosis or treatments for the organ-specific autoimmune diseases such as Sjögren's syndrome and clarifying how the local immune system regulates autoimmunity.
Takeshi Nitta, Shigeo Murata, Katsuhiro Sasaki, Hideki Fujii, Adiratna Mat Ripen, Naozumi Ishimaru, Shigeo Koyasu, Keiji Tanaka and Yousuke Takahama : Thymoproteasome shapes immunocompetent repertoire of CD8+ T cells., Immunity, Vol.32, No.1, 29-40, 2010.
(Summary)
How self-peptides displayed in the thymus contribute to the development of immunocompetent and self-protective T cells is largely unknown. In contrast, the role of thymic self-peptides in eliminating self-reactive T cells and thereby preventing autoimmunity is well established. A type of proteasome, termed thymoproteasome, is specifically expressed by thymic cortical epithelial cells (cTECs) and is required for the generation of optimal cellularity of CD8+ T cells. Here, we show that cTECs displayed thymoproteasome-specific peptide-MHC class I complexes essential for the positive selection of major and diverse repertoire of MHC class I-restricted T cells. CD8+ T cells generated in the absence of thymoproteasomes displayed a markedly altered T cell receptor repertoire that was defective in both allogeneic and antiviral responses. These results demonstrate that thymoproteasome-dependent self-peptide production is required for the development of an immunocompetent repertoire of CD8+ T cells.
Takeshi Nitta, Sachiko Nitta, Yu Lei, Martin Lipp and Yousuke Takahama : CCR7-mediated migration of developing thymocytes to the medulla is essential for negative selection to tissue-restricted antigens, Proceedings of the National Academy of Sciences of the United States of America, Vol.106, No.40, 17129-17133, 2009.
(Summary)
Immature double-positive thymocytes are generated in the thymic cortex, and on positive selection, are induced to differentiate into mature single-positive thymocytes and relocate to the medulla. CCR7 is pivotal for cortex-to-medulla migration of positively selected thymocytes, and CCR7-mediated migration to the medulla is essential for establishing central tolerance, thereby, preventing tissue-specific autoimmunity. However, it was unclear how CCR7-mediated migration to the medulla affects the establishment of self-tolerance. Here, we show that the deletion of thymocytes specific for insulin-promoter-driven tissue-restricted antigens (TRAs) is significantly impaired in CCR7- or CCR7-ligand-deficient mice. These results indicate that CCR7-mediated migration to the medulla contributes to the negative selection of TRA-reactive thymocytes.
Y Lei, C Liu, F Saito, Y Fukui and Yousuke Takahama : Role of DOCK2 and DOCK180 in fetal thymus colonization, European Journal of Immunology, Vol.39, No.10, 2695-2702, 2009.
(Summary)
Fetal thymus colonization is initiated before the vascularization of the thymus primordium. This prevascular colonization of the fetal thymus by T-lymphoid progenitor cells is guided by the coordination of CCR7- and CCR9-mediated chemokine signals. However, the intracellular signals that mediate the prevascular migration of T-lymphoid progenitor cells to the fetal thymus are unknown. Here we show that T-lymphoid progenitor cells in fetal mice express two closely related CDM family molecules, DOCK2 and DOCK180. We found that the prevascular fetal thymus accumulation in vivo was significantly reduced in mice doubly deficient for DOCK2 and DOCK180 but not in mice deficient for either DOCK2 or DOCK180. Immature T-lymphoid cells from mice doubly deficient for DOCK2 and DOCK180 were defective in their in vitro migration towards fetal thymus lobes. The T-lymphoid progenitor cells generated in mice lacking DOCK2 and DOCK180 were capable of T-cell development after their transfer into a fetal thymus environment, and the impaired fetal thymus colonization in mice deficient for DOCK2 and DOCK180 was not as severe as that in mice doubly deficient for CCR7 and CCR9. These results indicate that the combination of DOCK2 and DOCK180 plays a significant but not essential role in prevascular fetal thymus colonization.
N Iwanami, M Okada, VQ Hoa, Y Seo, H Mitani, T Sasaki, N Shimizu, H Kondoh, M Furutani-Seiki and Yousuke Takahama : Ethylnitrosourea-induced thymus-defective mutants identify roles of KIAA1440, TRRAP, and SKIV2L2 in teleost organ development, European Journal of Immunology, Vol.39, No.9, 2606-2616, 2009.
(Summary)
The thymus is an organ where T lymphocytes develop. Thymus development requires interactions of cells derived from three germ layers. However, the molecular mechanisms that control thymus development are not fully understood. To identify the genes that regulate thymus development, we previously carried out a large-scale screening for ethylnitrosourea-induced mutagenesis using medaka, Oryzias latipes, and established a panel of recessive thymus-lacking mutants. Here we report the identification of three genes responsible for these mutations. We found that the mutations in KIAA1440, TRRAP, and SKIV2L2 caused the defects in distinct steps of thymus development. We also found that these genes were widely expressed in many organs and that the mutations in these genes caused defects in the development of various other organs. These results enabled us to identify previously unknown roles of widely expressed genes in medaka organ development. The possible reasons why thymus-defective teleost mutants could be used to identify widely expressed genes and future strategies to increase the likelihood of identifying genes that specifically regulate thymus development are discussed.
(Keyword)
Adaptor Proteins, Signal Transducing / Alternative Splicing / Animals / Base Sequence / Ethylnitrosourea / Exons / Molecular Sequence Data / Mutation / Nuclear Proteins / Organogenesis / Oryzias / RNA Helicases / Thymus Gland
Andrea P. Martin, Tatjana Marinkovic, Claudia Canasto-Chibuque, Rauf Latif, Jay C. Unkeless, Terry F. Davies, Yousuke Takahama, Glaucia C. Furtado and Sergio A. Lira : CCR7 deficiency in NOD mice leads to thyroiditis and primary hypothyroidism, The Journal of Immunology, Vol.183, No.5, 3073-3080, 2009.
(Summary)
CCR7 is involved in the initiation of immune responses and has been recently implicated in the control of tolerance. To analyze the role of CCR7 in autoimmunity, we backcrossed CCR7(ko/ko) mice (in which ko signifies deficient) onto the autoimmune-prone NOD background. Surprisingly, NODCCR7(ko/ko) mice never developed diabetes, but showed severe inflammation in multiple tissues including thyroid, lung, stomach, intestine, uterus, and testis. NODCCR7(ko/ko) mice had a marked enlargement of the thyroid gland (goiter) that was associated with circulating autoantibodies against thyroglobulin, and development of primary hypothyroidism (decreased levels of serum thyroxin, and augmented levels of thyroid-stimulating hormone in the pituitary gland), features found in Hashimoto's thyroiditis. Cells isolated from diseased thyroids and activated splenocytes from NODCCR7(ko/ko) animals induced goiter in NOD.SCID recipients, demonstrating that autoreactive cells were generated in the absence of CCR7. Moreover, thyroid disease could be accelerated in young NODCCR7(ko/ko) mice by immunization with thyroglobulin. These results demonstrate the complexity in the generation of multiple autoimmune phenotypes in NOD mice and indicate that CCR7 is a key molecule in their development.
Yousuke Takahama, T Saito, H Kawamoto, M Itoi, RL Boyd, A Chidgey, R Zamoyska, GA Hollander, G Anderson, N Taylor, HT Petrie and J Nikolich-Zugich : The global thymus network: past, present, and future, Trends in Immunology, Vol.30, No.5, 191-192, 2009.
(Keyword)
Congresses as Topic / T-Lymphocytes / Thymus Gland
DA Sultana, Shuhei Tomita, M Hamada, Y Iwanaga, Y Kitahama, NV Khang, S Hirai, Izumi Ohigashi, S Nitta, T Amagai, S Takahashi and Yousuke Takahama : Gene expression profile of the third pharyngeal pouch reveals role of mesenchymal MafB in embryonic thymus development, Blood, Vol.113, No.13, 2976-2987, 2009.
(Summary)
The thymus provides a microenvironment that induces the differentiation of T-progenitor cells into functional T cells and that establishes a diverse yet self-tolerant T-cell repertoire. However, the mechanisms that lead to the development of the thymus are incompletely understood. We report herein the results of screening for genes that are expressed in the third pharyngeal pouch, which contains thymic primordium. Polymerase chain reaction (PCR)-based cDNA subtraction screening for genes expressed in microdissected tissues of the third pharyngeal pouch rather than the second pharyngeal arch yielded one transcription factor, MafB, which was predominantly expressed in CD45(-)IA(-)PDGFRalpha(+) mesenchymal cells and was detectable even in the third pharyngeal pouch of FoxN1-deficient nude mice. Interestingly, the number of CD45(+) cells that initially accumulated in the embryonic thymus was significantly decreased in MafB-deficient mice. Alterations of gene expression in the embryonic thymi of MafB-deficient mice included the reduced expression of Wnt3 and BMP4 in mesenchymal cells and of CCL21 and CCL25 in epithelial cells. These results suggest that MafB expressed in third pharyngeal pouch mesenchymal cells critically regulates lymphocyte accumulation in the embryonic thymus.
Magali Irla, Ste´phanie Hugues, Jason Gill, Takeshi Nitta, Yu Hikosaka, Ifor R Williams, Franc¸ois-Xavier Hubert, Hamish S Scott, Yousuke Takahama, Georg A Holla¨nder and Walter Reith : Autoantigen-specific interactions with CD4+ thymocytes control mature medullary thymic epithelial cell cellularity., Immunity, Vol.29, No.3, 451-463, 2008.
(Summary)
Medullary thymic epithelial cells (mTECs) are specialized for inducing central immunological tolerance to self-antigens. To accomplish this, mTECs must adopt a mature phenotype characterized by expression of the autoimmune regulator Aire, which activates the transcription of numerous genes encoding tissue-restricted self-antigens. The mechanisms that control mature Aire(+) mTEC development in the postnatal thymus remain poorly understood. We demonstrate here that, although either CD4(+) or CD8(+) thymocytes are sufficient to sustain formation of a well-defined medulla, expansion of the mature mTEC population requires autoantigen-specific interactions between positively selected CD4(+) thymocytes bearing autoreactive T cell receptor (TCR) and mTECs displaying cognate self-peptide-MHC class II complexes. These interactions also involve the engagement of CD40 on mTECs by CD40L induced on the positively selected CD4(+) thymocytes. This antigen-specific TCR-MHC class II-mediated crosstalk between CD4(+) thymocytes and mTECs defines a unique checkpoint in thymic stromal development that is pivotal for generating a mature mTEC population competent for ensuring central T cell tolerance.
Taishin Akiyama, Yusuke Shimo, Hiromi Yanai, Junwen Qin, Daisuke Ohshima, Yuya Maruyama, Yukiko Asaumi, Juli Kitazawa, Hiroshi Takayanagi, Josef Penninger, Mitsuru Matsumoto, Takeshi Nitta, Yousuke Takahama and Jun-ichiro Inoue : The tumor necrosis factor family receptors RANK and CD40 cooperatively establish the thymic medullary microenvironment and self-tolerance., Immunity, Vol.29, No.3, 423-437, 2008.
(Summary)
Medullary thymic epithelial cells (mTECs) establish T cell self-tolerance through the expression of autoimmune regulator (Aire) and peripheral tissue-specific self-antigens. However, signals underlying mTEC development remain largely unclear. Here, we demonstrate crucial regulation of mTEC development by receptor activator of NF-kappaB (RANK) and CD40 signals. Whereas only RANK signaling was essential for mTEC development during embryogenesis, in postnatal mice, cooperation between CD40 and RANK signals was required for mTEC development to successfully establish the medullary microenvironment. Ligation of RANK or CD40 on fetal thymic stroma in vitro induced mTEC development in a tumor necrosis factor-associated factor 6 (TRAF6)-, NF-kappaB inducing kinase (NIK)-, and IkappaB kinase beta (IKKbeta)-dependent manner. These results show that developmental-stage-dependent cooperation between RANK and CD40 promotes mTEC development, thereby establishing self-tolerance.
Yu Hikosaka, Takeshi Nitta, Izumi Ohigashi, Kouta Yano, Naozumi Ishimaru, Yoshio Hayashi, Mitsuru Matsumoto, Koichi Matsuo, Josef M Penninger, Hiroshi Takayanagi, Yoshifumi Yokota, Hisakata Yamada, Yasunobu Yoshikai, Jun-ichiro Inoue, Taishin Akiyama and Yousuke Takahama : The cytokine RANKL produced by positively selected thymocytes fosters medullary thymic epithelial cells that express autoimmune regulator., Immunity, Vol.29, No.3, 438-450, 2008.
(Summary)
The thymic medulla provides a microenvironment where medullary thymic epithelial cells (mTECs) express autoimmune regulator and diverse tissue-restricted genes, contributing to launching self-tolerance. Positive selection is essential for thymic medulla formation via a previously unknown mechanism. Here we show that the cytokine RANK ligand (RANKL) was produced by positively selected thymocytes and regulated the cellularity of mTEC by interacting with RANK and osteoprotegerin. Forced expression of RANKL restored thymic medulla in mice lacking positive selection, whereas RANKL perturbation impaired medulla formation. These results indicate that RANKL produced by positively selected thymocytes is responsible for fostering thymic medulla formation, thereby establishing central tolerance.
N Iwanami, T Higuchi, Y Sasano, T Fujiwara, V Hoa, M Okada, S Talukder, S Kunimatsu, J Li, F Saito, C Bhattacharya, A Matin, T Sasaki, N Shimizu, H Mitani, H Himmelbauer, A Momoi, H Kondoh, M Furutani-Seiki and Yousuke Takahama : WDR55 is a nucleolar modulator of ribosomal RNA synthesis, cell cycle progression, and teleost organ development., PLoS Genetics, Vol.4, No.8, e1000171, 2008.
(Summary)
The thymus is a vertebrate-specific organ where T lymphocytes are generated. Genetic programs that lead to thymus development are incompletely understood. We previously screened ethylnitrosourea-induced medaka mutants for recessive defects in thymus development. Here we report that one of those mutants is caused by a missense mutation in a gene encoding the previously uncharacterized protein WDR55 carrying the tryptophan-aspartate-repeat motif. We find that WDR55 is a novel nucleolar protein involved in the production of ribosomal RNA (rRNA). Defects in WDR55 cause aberrant accumulation of rRNA intermediates and cell cycle arrest. A mutation in WDR55 in zebrafish also leads to analogous defects in thymus development, whereas WDR55-null mice are lethal before implantation. These results indicate that WDR55 is a nuclear modulator of rRNA synthesis, cell cycle progression, and embryonic organogenesis including teleost thymus development.
Yousuke Takahama, K Tanaka and S Murata : Modest cortex and promiscuous medulla for thymic repertoire formation., Trends in Immunology, Vol.29, No.6, 251-255, 2008.
(Summary)
Recent advances in the understanding of medullary thymic epithelial cell biology, and especially of their promiscuous gene expression, have highlighted the indispensable role of thymic medulla in shaping a self-tolerant T-cell repertoire. Additionally, our recent results have shown that cortical thymic epithelial cells possess a unique proteasome (the so-called thymoproteasome), which seems to possess limited protein degradation capability for generating peptides that are loaded onto class I major histocompatibility complex molecules. We discuss here the unique role of thymoproteasomes in the development and repertoire formation of CD8+ T cells, focusing on the stepwise and contrasting roles of cortical epithelial cells and medullary epithelial cells. These results could offer fundamental new insights into the molecular mechanisms of T-cell repertoire selection.
S Murata, Yousuke Takahama and K Tanaka : Thymoproteasome: probable role in generating positively selecting peptides, Current Opinion in Immunology, Vol.20, No.2, 192-196, 2008.
(Summary)
The proteasome is the protein destroying machinery conserved in all eukaryotes and plays essential roles in various cellular processes. Apart from the conserved 'standard' proteasome, a special type of proteasome called 'immunoproteasome' exists in vertebrates for better presentation of antigenic peptides on MHC class I molecules. Recently, another vertebrate-specific proteasome was discovered in the thymus. This 'thymoproteasome' has a novel catalytic subunit 'beta5t' with unusual enzymatic activity and is expressed exclusively in cortical thymic epithelial cells (cTECs), which catalyze positive selection of developing thymocytes. beta5t-deficient mice exhibit severe impairment in CD8(+) T cell development. These findings suggest that cTECs are quite unique cells capable of presenting a unique set of self-peptides that are not seen in other cells and are required for positive selection of CD8(+) T cells.
Takeshi Nitta, Shigeo Murata, Tomoo Ueno, Keiji Tanaka and Yousuke Takahama : Thymic microenvironments for T-cell repertoire formation., Advances in Immunology, Vol.99, 59-94, 2008.
(Summary)
Functionally competent immune system includes a functionally competent T-cell repertoire that is reactive to foreign antigens but is tolerant to self-antigens. The repertoire of T cells is primarily formed in the thymus through positive and negative selection of developing thymocytes. Immature thymocytes that undergo V(D)J recombination of T-cell antigen receptor (TCR) genes and that express the virgin repertoire of TCRs are generated in thymic cortex. The recent discovery of thymoproteasomes, a molecular complex specifically expressed in cortical thymic epithelial cells (cTEC), has revealed a unique role of cTEC in cuing the further development of immature thymocytes in thymic cortex, possibly by displaying unique self-peptides that induce positive selection. Cortical thymocytes that receive TCR-mediated positive selection signals are destined to survive for further differentiation and are induced to express CCR7, a chemokine receptor. Being attracted to CCR7 ligands expressed by medullary thymic epithelial cells (mTEC), CCR7-expressing positively selected thymocytes relocate to thymic medulla. The medullary microenvironment displays another set of unique self-peptides for trimming positively selected T-cell repertoire to establish self-tolerance, via promiscuous expression of tissue-specific antigens by mTEC and efficient antigen presentation by dendritic cells. Recent results demonstrate that tumor necrosis factor (TNF) superfamily ligands, including receptor activating NF-kappaB ligand (RANKL), CD40L, and lymphotoxin, are produced by positively selected thymocytes and pivotally regulate mTEC development and thymic medulla formation.
Hiroko Hagiwara, Kazumi Sawakami-Kobayashi, Midori Yamamoto, Shoji Iwasaki, Mika Sugiura, Hatsumi Abe, Sumiko Kunihiro-Ohashi, Kumiko Takase, Noriko Yamane, Kaoru Kato, Renkon Son, Michihiro Nakamura, Osamu Segawa, Mamiko Yoshida, Masafumi Yohda, Hideji Tajima, Masato Kobori, Yousuke Takahama, Mitsuo Itakura and Masayuki Machida : Development of an automated SNP analysis method using a paramagnetic beads handling robot., Biotechnology and Bioengineering, Vol.98, No.2, 420-428, 2007.
(Summary)
Biological and medical importance of the single nucleotide polymorphism (SNP) has led to development of a wide variety of methods for SNP typing. Aiming for establishing highly reliable and fully automated SNP typing, we have developed the adapter ligation method in combination with the paramagnetic beads handling technology, Magtration(R). The method utilizes sequence specific ligation between the fluorescently labeled adapter and the sample DNAs at the cohesive end produced by a type IIS restriction enzyme. Evaluation of the method using human genomic DNA showed clear discrimination of the three genotypes without ambiguity using the same reaction condition for any SNPs examined. The operations following PCR amplification were automatically performed by the Magtration(R)-based robot that we have previously developed. Multiplex typing of two SNPs in a single reaction by using four fluorescent dyes was successfully preformed at the almost same sensitivity and reliability as the single typing. These results demonstrate that the automated paramagnetic beads handling technology, Magtration(R), is highly adaptable to the automated SNP analysis and that our method best fits to an automated in-house SNP typing for laboratory and medical uses.
(Keyword)
Equipment Design / Genetic Testing / Genome, Human / Genotype / Humans / Magnetics / Polymerase Chain Reaction / Polymorphism, Single Nucleotide / Robotics / Sequence Analysis, DNA
Jie Li, Norimasa Iwanami, VQ Quynh Hoa, Makoto Furutani-Seiki and Yousuke Takahama : Noninvasive intravital imaging of thymocyte dynamics in medaka., The Journal of Immunology, Vol.179, No.3, 1605-1615, 2007.
(Summary)
In vivo imaging of thymocytes has not been accomplished due to their localization deep within opaque body and high susceptibility to surgical stress. To overcome these problems, medaka is useful because of transparency and ex-uterine development. We report the noninvasive detection of thymocytes in transgenic medaka that express fluorescent protein under the control of immature-lymphocyte-specific rag1. We show that lymphoid progenitor cells colonize the thymus primordium in an anterior-to-posterior orientation-specific manner, revealing that extrathymic anterior components guide prevascular thymus colonization. We also show that developing thymocytes acquire "random walk motility" along with the expression of Ag receptors and coreceptors, suggesting that thymocyte walking is initiated at the developmental stage for repertoire selection. Thus, transgenic medaka enables real-time intravital imaging of thymocytes without surgical invasion.
(Keyword)
Animals / Animals, Genetically Modified / Cell Movement / Genes, RAG-1 / Green Fluorescent Proteins / Homeodomain Proteins / Laser Scanning Cytometry / Microscopy, Fluorescence / Microscopy, Video / Molecular Sequence Data / Oryzias / T-Lymphocytes / Thymus Gland
(Link to Search Site for Scientific Articles)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 17641027
WE Jenkinson, SW Rossi, SM Parnell, WW Agace, Yousuke Takahama, EJ Jenkinson and G Anderson : Chemokine receptor expression defines heterogeneity in the earliest thymic migrants., European Journal of Immunology, Vol.37, No.8, 2090-2096, 2007.
(Summary)
Chemokine signaling has been implicated in directing colonization of the fetal thymus by hematopoietic precursors. However, the patterns of expression of the chemokine receptors responsible for directing thymic colonization by the earliest thymic migrants remain unknown. We have identified heterogeneity within the earliest thymus seeding cells based on chemokine receptor expression. By analyzing the first wave of progenitors to colonize the thymus at E12 of gestation, we show that multiple chemokine receptors are expressed by T-lymphoid precursors present within perithymic mesenchyme, while expression of chemokine ligands is limited to CCL21, CCL25 and CXCL12, which are located in distinct epithelial and mesenchymal compartments of the thymic/parathyroid anlagen. Collectively, these results identify multiple populations of T-lymphoid precursors colonizing the fetal thymus and provide evidence for several potential pathways mediating migration of precursors into the embryonic thymus.
S Murata, K Sasaki, T Kishimoto, S Niwa, H Hayashi, Yousuke Takahama and K Tanaka : Regulation of CD8+ T cell development by thymus-specific proteasomes., Science, Vol.316, No.5829, 1349-1353, 2007.
(Summary)
Proteasomes are responsible for generating peptides presented by the class I major histocompatibility complex (MHC) molecules of the immune system. Here, we report the identification of a previously unrecognized catalytic subunit called beta5t. beta5t is expressed exclusively in cortical thymic epithelial cells, which are responsible for the positive selection of developing thymocytes. Although the chymotrypsin-like activity of proteasomes is considered to be important for the production of peptides with high affinities for MHC class I clefts, incorporation of beta5t into proteasomes in place of beta5 or beta5i selectively reduces this activity. We also found that beta5t-deficient mice displayed defective development of CD8(+) T cells in the thymus. Our results suggest a key role for beta5t in generating the MHC class I-restricted CD8(+) T cell repertoire during thymic selection.
S Rossi, LT Jeker, Tomoo Ueno, S Kuse, MP Keller, A Zuklys, A Gudkov, Yousuke Takahama, W Krenger, BR Blazar and GA Hollander : Keratinocyte growth factor enhances post-natal T cell development via improvement in proliferation and function of thymic epithelial cells, Blood, Vol.109, No.9, 3803-3811, 2007.
(Summary)
The systemic administration of keratinocyte growth factor (KGF) enhances T-cell lymphopoiesis in normal mice and mice that received a bone marrow transplant. KGF exerts protection to thymic stromal cells from cytoablative conditioning and graft-versus-host disease-induced injury. However, little is known regarding KGF's molecular and cellular mechanisms of action on thymic stromal cells. Here, we report that KGF induces in vivo a transient expansion of both mature and immature thymic epithelial cells (TECs) and promotes the differentiation of the latter type of cells. The increased TEC numbers return within 2 weeks to normal values and the microenvironment displays a normal architectural organization. Stromal changes initiate an expansion of immature thymocytes and permit regular T-cell development at an increased rate and for an extended period of time. KGF signaling in TECs activates both the p53 and NF-kappaB pathways and results in the transcription of several target genes necessary for TEC function and T-cell development, including bone morphogenetic protein 2 (BMP2), BMP4, Wnt5b, and Wnt10b. Signaling via the canonical BMP pathway is critical for the KGF effects. Taken together, these data provide new insights into the mechanism(s) of action of exogenous KGF on TEC function and thymopoiesis.
Takeshi Nitta and Yousuke Takahama : The lymphocyte guard-IANs: regulation of lymphocyte survival by IAN/GIMAP family proteins, Trends in Immunology, Vol.28, No.2, 58-65, 2007.
(Summary)
The life-or-death decision of immune cells makes an essential contribution to immune-system development and the regulation of immune responses. A new family of cell-survival regulators expressed in lymphocytes, termed immune-associated nucleotide-binding proteins (IANs) [also known as GTPase of immunity-associated proteins (GIMAPs)], has been described. The IAN/GIMAP family consists of GTP-binding proteins that share a unique primary structure and whose expression is finely regulated by T-cell receptor signals. Recent studies have shown that IAN/GIMAP family proteins crucially regulate the survival of T cells during development, selection and homeostasis, and are possibly linked to the onset of T-lymphopenia, leukemia and autoimmunity. IAN/GIMAP family proteins might also take part in mitochondrial regulation of lymphocyte apoptosis by interacting with Bcl-2 family proteins.
T. Yasuda, T. Kuwabara, H. Nakano, K. Aritomi, T. Onodera, M. Lipp, Yousuke Takahama and T Kakiuchi : Chemokines CCL19 and CCL21 promote activation-induced cell death of antigen-responding T cells, Blood, Vol.109, No.2, 449-456, 2007.
(Summary)
Secondary lymphoid organs (SLOs) provide a niche for the initiation and regulation of T-cell responses, but the mechanisms have been poorly understood. We investigated the influence of chemokines CCL19 and CCL21 constitutively expressed in SLOs on activation-induced cell death (AICD) of CD4+ T cells. When paucity of lymph node T cells (plt) mutant mice lacking expression of CCL19/CCL21 were primed with OVA/CFA, both expansion of OVA-responding CD4+ T cells in the draining lymph nodes and an in vitro recall response were prolonged as compared with responses in wild-type (WT) mice. The apoptotic cell frequency among OVA-responding CD4+ T cells was similarly low in plt/plt and WT mice during the clonal expansion phase. However, during the clonal contraction phase, the frequency never increased in plt/plt mice, whereas in WT mice it continuously increased to a peak 18 days after immunization. The presence of CCL19/CCL21 during the in vitro stimulation of CD4+ T cells with anti-CD3 plus anti-CD28 significantly enhanced in vitro AICD induction of the restimulated T cells, partially through enhancing expression of Fas ligand. Our results suggest that CCL19/CCL21 produced by stromal cells and antigen-presenting cells regulate CD4+ T-cell immune responses in SLOs by promoting AICD.
(Keyword)
Animals / CD4-Positive T-Lymphocytes / Cell Death / Chemokine CCL19 / Chemokine CCL21 / Chemokines, CC / Lymphoid Tissue / Mice / Mice, Inbred BALB C / Mice, Inbred C57BL / Sensitivity and Specificity
Cunlan Liu, Fumi Saito, Zhijie Liu, Yu Lei, Shoji Uehara, Paul Love, Martin Lipp, Shunzo Kondo, Nancy Manley and Yousuke Takahama : Coordination between CCR7- and CCR9-mediated chemokine signals in prevascular fetal thymus colonization., Blood, Vol.108, No.8, 2531-2539, 2006.
(Summary)
Thymus seeding by T-lymphoid progenitor cells is a prerequisite for T-cell development. However, molecules guiding thymus colonization and their roles before and after thymus vascularization are unclear. Here we show that mice doubly deficient for chemokine receptors CCR7 and CCR9 were defective specifically in fetal thymus colonization before, but not after, thymus vascularization. The defective prevascular fetal thymus colonization was followed by selective loss of the first wave of T-cell development generating epidermal Vgamma3(+) gammadelta T cells. Unexpectedly, CCL21, a CCR7 ligand, was expressed not by Foxn1-dependent thymic primordium but by Gcm2-dependent parathyroid primordium, whereas CCL25, a CCR9 ligand, was predominantly expressed by Foxn1-dependent thymic primordium, revealing the role of the adjacent parathyroid in guiding fetal thymus colonization. These results indicate coordination between Gcm2-dependent parathyroid and Foxn1-dependent thymic primordia in establishing CCL21/CCR7- and CCL25/CCR9-mediated chemokine guidance essential for prevascular fetal thymus colonization.
Takeshi Nitta, Mariam Nasreen, Takafumi Seike, Atsushi Goji, Izumi Ohigashi, Tadaaki Miyazaki, Tsutomu Ohta, Masamoto Kanno and Yousuke Takahama : IAN family critically regulates survival and development of T lymphocytes, PLoS Biology, Vol.4, No.4, e103-e115, 2006.
(Summary)
The IAN (immune-associated nucleotide-binding protein) family is a family of functionally uncharacterized GTP-binding proteins expressed in vertebrate immune cells and in plant cells during antibacterial responses. Here we show that all eight IAN family genes encoded in a single cluster of mouse genome are predominantly expressed in lymphocytes, and that the expression of IAN1, IAN4, and IAN5 is significantly elevated upon thymic selection of T lymphocytes. Gain-of-function experiments show that the premature overexpression of IAN1 kills immature thymocytes, whereas short hairpin RNA-mediated loss-of-function studies show that IAN4 supports positive selection. The knockdown of IAN5 perturbs the optimal generation of CD4/CD8 double-positive thymocytes and reduces the survival of mature T lymphocytes. We also show evidence suggesting that IAN4 and IAN5 are associated with anti-apoptotic proteins Bcl-2 and Bcl-xL, whereas IAN1 is associated with pro-apoptotic Bax. Thus, the IAN family is a novel family of T cell-receptor-responsive proteins that critically regulate thymic development and survival of T lymphocytes and that potentially exert regulatory functions through the association with Bcl-2 family proteins.
Hirotsugu Kurobe, Cunian Liu, Tomoo Ueno, Fumi Saito, Izumni Ohigashi, Natalle Seach, Rieko Arakaki, Yoshio Hayashi, Tetsuya Kitagawa, Martin Lipp, Richard L. Boyd and Yousuke Takahama : CCR7-Dependent Cortex-to-Medulla Migration of Positively Selected Thymocytes Is Essential for Establishing Central Tolerance, Immunity, Vol.24, No.2, 165-177, 2006.
(Summary)
Immature CD4+CD8+ thymocytes, which are generated in the thymic cortex, are induced upon positive selection to differentiate into mature T lymphocytes and relocate to the thymic medulla. It was recently shown that a chemokine signal via CCR7 is essential for the cortex-to-medulla migration of positively selected thymocytes in the thymus. However, the role of the cortex-to-medulla migration in T cell development and selection has remained unclear. The present study shows that the developmental kinetics and the thymic export of mature thymocytes were undisturbed in adult mice lacking CCR7 or its ligands (CCR7L). The inhibition of sphingosine-1-phosphate-mediated lymphocyte egress from the thymus led to the accumulation of mature thymocytes in the cortex of CCR7- or CCR7L-deficient mice, unlike the accumulation in the medulla of normal mice, thereby suggesting that mature thymocytes may be exported directly from the cortex in the absence of CCR7 signals. However, the thymocytes that were generated in the absence of CCR7 or CCR7L were potent in causing autoimmune dacryoadenitis and sialadenitis in mice and were thus incapable of establishing central tolerance to organ-specific antigens. These results indicate that CCR7-mediated cortex-to-medulla migration of thymocytes is essential for establishing central tolerance rather than for supporting the maturation or export of thymocytes.
Georg Hollander, Jason Gill, Saulus Zuklys, Norimasa Iwanami, Cunlan Liu and Yousuke Takahama : Cellular and molecular events during early thymus development., Immunological Reviews, Vol.209, No.1, 28-46, 2006.
(Summary)
The thymic stromal compartment consists of several cell types that collectively enable the attraction, survival, expansion, migration, and differentiation of T-cell precursors. The thymic epithelial cells constitute the most abundant cell type of the thymic microenvironment and can be differentiated into morphologically, phenotypically, and functionally separate subpopulations of the postnatal thymus. All thymic epithelial cells are derived from the endodermal lining of the third pharyngeal pouch. Very soon after the formation of a thymus primordium and prior to its vascularization, thymic epithelial cells orchestrate the first steps of intrathymic T-cell development, including the attraction of lymphoid precursor cells to the thymic microenvironment. The correct segmentation of pharyngeal epithelial cells and their subsequent crosstalk with cells in the pharyngeal arches are critical prerequisites for the formation of a thymus anlage. Mutations in several transcription factors and their target genes have been informative to detail some of the complex mechanisms that control the development of the thymus anlage. This review highlights recent findings related to the genetic control of early thymus organogenesis and provides insight into the molecular basis by which lymphocyte precursors are attracted to the thymus.
Yousuke Takahama : Journey through the thymus: stromal guides for T-cell development and selection., Nature Reviews. Immunology, Vol.6, No.2, 127-135, 2006.
(Summary)
Lympho-stromal interactions in multiple microenvironments within the thymus have a crucial role in the regulation of T-cell development and selection. Recent studies have implicated that chemokines that are produced by thymic stromal cells have a pivotal role in positioning developing T cells within the thymus. In this Review, I discuss the importance of stroma-derived chemokines in guiding the traffic of developing thymocytes, with an emphasis on the processes of cortex-to-medulla migration and T-cell-repertoire selection, including central tolerance.
Daniel HD Gray, Tomoo Ueno, Ann P Chidgey, Mark Malin, Gabrielle L Goldberg, Yousuke Takahama and Richard L Boyd : Controlling the thymic microenvironment, Current Opinion in Immunology, Vol.17, No.2, 137-143, 2005.
(Summary)
T-cell development in the thymus is a stepwise process, mediated by a variety of stromal cells in different regions of the organ. Although the cellular composition of the thymic microenvironment has been known for over a decade, the molecular cues that govern its formation are only beginning to be understood. Stromal-derived chemokines attract T-cell precursors to the thymus and direct maturing thymocytes to appropriate niches for their further development. Reciprocal signals from developing T cells provide crosstalk that is essential for establishment and maintenance of the thymic microenvironment. Elucidation of the molecular players involved and their context within the organ is the challenge for the field today. This knowledge could then be translated to clinical restoration of thymic function and T-cell reconstitution.
Noriyuki Kuroda, Tasuku Mitani, Naoki Takeda, Naozumi Ishimaru, Rieko Arakaki, Yoshio Hayashi, Yoshimi Bando, Keisuke Izumi, Takeshi Takahashi, Takashi Nomura, Shimon Sakaguchi, Tomoo Ueno, Yousuke Takahama, Daisuke Uchida, Shijie Sun, Fumiko Kajiura, Yasuhiro Mouri, Hongwei Han, Akemi Matsushima, Gen Yamada and Mitsuru Matsumoto : Development of autoimmunity against transcriptionally unrepressed target antigen in the thymus of Aire-deficient mice, The Journal of Immunology, Vol.174, No.4, 1862-1870, 2005.
(Summary)
Autoimmune regulator (AIRE) gene mutation is responsible for the development of organ-specific autoimmune disease with monogenic autosomal recessive inheritance. Although Aire has been considered to regulate the elimination of autoreactive T cells through transcriptional control of tissue-specific Ags in thymic epithelial cells, other mechanisms of AIRE-dependent tolerance remain to be investigated. We have established Aire-deficient mice and examined the mechanisms underlying the breakdown of self-tolerance. The production and/or function of immunoregulatory T cells were retained in the Aire-deficient mice. The mice developed Sjogren's syndrome-like pathologic changes in the exocrine organs, and this was associated with autoimmunity against a ubiquitous protein, alpha-fodrin. Remarkably, transcriptional expression of alpha-fodrin was retained in the Aire-deficient thymus. These results suggest that Aire regulates the survival of autoreactive T cells beyond transcriptional control of self-protein expression in the thymus, at least against this ubiquitous protein. Rather, Aire may regulate the processing and/or presentation of self-proteins so that the maturing T cells can recognize the self-Ags in a form capable of efficiently triggering autoreactive T cells. With the use of inbred Aire-deficient mouse strains, we also demonstrate the presence of some additional factor(s) that determine the target-organ specificity of the autoimmune disease caused by Aire deficiency.
Tomoo Ueno, Cunlan Liu, Takeshi Nitta and Yousuke Takahama : Development of T-lymphocytes in mouse fetal thymus organ culture., Methods in Molecular Biology, Vol.290, 117-134, 2005.
(Summary)
Fetal thymus organ culture (FTOC) is a unique and powerful culture system that allows intrathymic T-lymphocyte development in vitro. T-cell development in FTOC well represents fetal thymocyte development in vivo. Here, we describe the basic method for FTOC as well as several related techniques, including the reconstitution of thymus lobes with T-lymphoid progenitor cells, high-oxygen submersion culture, time-lapse visualization of thymic emigration, reaggregation culture, and retrovirus-mediated gene transfer to developing thymocytes in FTOC.
Cunlan Liu, Tomoo Ueno, Sachiyo Kuse, Fumi Saito, Takeshi Nitta, Luca Piali, Hideki Nakano, Terutaka Kakiuchi, Martin Lipp, Georg A. Hollander and Yousuke Takahama : The role of CCL21 in recruitment of T-precursor cells to fetal thymi, Blood, Vol.105, No.1, 31-39, 2005.
(Summary)
During embryonic development, T-lymphoid precursor cells colonize the thymus. Chemoattraction by the fetal thymus is thought to mediate T-precursor cell colonization. However, the molecules that attract T-precursor cells to the thymus remain unclear. By devising time-lapse visualization in culture, the present results show that alymphoid fetal thymus lobes attract T-precursor cells from fetal liver or fetal blood. CD4(-)CD8(-)CD25(-)CD44+ fetal thymocytes retained the activity to specifically re-enter the thymus. The attraction was predominantly due to I-A-expressing thymic epithelial cells and was mediated by pertussis toxin-sensitive G-protein signals. Among the chemokines produced by the fetal thymus, CCL21, CCL25, and CXCL12 could attract CD4(-)CD8(-)CD25(-)CD44+ fetal thymocytes. However, fetal thymus colonization was markedly diminished by neutralizing antibodies specific for CCL21 and CCL25, but not affected by anti-CXCL12 antibody. Fetal thymus colonization was partially defective in CCL21-deficient plt/plt mice and was further diminished by anti-CCL25 antibody. These results indicate that CCL21 is involved in the recruitment of T-cell precursors to the fetal thymus and suggest that the combination of CCL21 and CCL25 plays a major role in fetal thymus colonization.
Tomoo Ueno, Fumi Saito, Daniel H.D. Gray, Sachiyo Kuse, Kunio Hieshima, Hideki Nakano, Terutaka Kakiuchi, Martin Lipp, Richard L. Boyd and Yousuke Takahama : CCR7 signals are essential for cortex-to-medulla migration of developing thymocytes., The Journal of Experimental Medicine, Vol.200, No.4, 493-505, 2004.
(Summary)
Upon TCR-mediated positive selection, developing thymocytes relocate within the thymus from the cortex to the medulla for further differentiation and selection. However, it is unknown how this cortex-medulla migration of thymocytes is controlled and how it controls T cell development. Here we show that in mice deficient for CCR7 or its ligands mature single-positive thymocytes are arrested in the cortex and do not accumulate in the medulla. These mutant mice are defective in forming the medullary region of the thymus. Thymic export of T cells in these mice is compromised during the neonatal period but not in adulthood. Thymocytes in these mice show no defects in maturation, survival, and negative selection to ubiquitous antigens. TCR engagement of immature cortical thymocytes elevates the cell surface expression of CCR7. These results indicate that CCR7 signals are essential for the migration of positively selected thymocytes from the cortex to the medulla. CCR7-dependent cortex-medulla migration of thymocytes plays a crucial role in medulla formation and neonatal T cell export but is not essential for maturation, survival, negative selection, and adult export of thymocytes.
Fumiko Kajiura, Shijie Sun, Takashi Nomura, Keisuke Izumi, Tomoo Ueno, Yoshimi Bando, Noriyuki Kuroda, Hongwei Han, Yi Li, Akemi Matsushima, Yousuke Takahama, Shimon Sakaguchi, Tasuku Mitani and Mitsuru Matsumoto : NF-κB-inducing kinase establishes self-tolerance in a thymic stroma-dependent manner, The Journal of Immunology, Vol.172, No.4, 2067-2075, 2004.
(Summary)
Physical contact between thymocytes and the thymic stroma is essential for T cell maturation and shapes the T cell repertoire in the periphery. Stromal elements that control these processes still remain elusive. We used a mouse strain with mutant NF-kappaB-inducing kinase (NIK) to examine the mechanisms underlying the breakdown of self-tolerance. This NIK-mutant strain manifests autoimmunity and disorganized thymic structure with abnormal expression of Rel proteins in the stroma. Production of immunoregulatory T cells that control autoreactive T cells was impaired in NIK-mutant mice. The autoimmune disease seen in NIK-mutant mice was reproduced in athymic nude mice by grafting embryonic thymus from NIK-mutant mice, and this was rescued by supply of exogenous immunoregulatory T cells. Impaired production of immunoregulatory T cells by thymic stroma without normal NIK was associated with altered expression of peripheral tissue-restricted Ags, suggesting an essential role of NIK in the thymic microenvironment in the establishment of central tolerance.
MA Sheard, C Liu and Yousuke Takahama : Developmental status of CD4-CD8+ and CD4+CD8- thymocytes with medium expression of CD3, European Journal of Immunology, Vol.34, No.1, 25-35, 2004.
(Summary)
In normal mice, more than 10% of thymocytes in the CD4+CD8- and CD4-CD8+ single-positive (SP) subsets express a medium level of CD3 on the cell surface. However, the fate of CD3medium cells is unclear. The CD3medium SP subpopulations might contain (i) cells in an immature stage of the pathways leading to CD3high cells, (ii) cells in developmental pathways that do not lead to CD3high cells, or (iii) cells that have been negatively selected. We found that sorted CD3medium CD4+CD8- thymocytes from adult mice up-regulated CD3 to high levels in reaggregation thymus organ culture. Unlike their CD3high counterparts, CD3medium CD4+CD8- thymocytes were unable to undergo chemotaxis towards the chemokines CCL19 and CCL21. CD3medium thymocytes of both CD4+CD8- and CD4-CD8+ subsets were also considerably more responsive than CD3high SP cells to apoptotic signals induced in vitro by ligation of CD95 (Fas/APO-1) or by dexamethasone. In both SP subsets, a higher frequency of thymocytes expressing forbidden Vbeta+ T cell receptors reactive with endogenous mammary tumor virus superantigens was found in CD3medium subpopulations than in CD3high subpopulations. These findings argue that the CD3medium SP thymocyte subpopulations contain apoptosis-susceptible precursor cells of CD3high SP cells and are subject to negatively selecting pressures.
Shuhei Tomita, Hou-Bo Jiang, Tomoo Ueno, Satoshi Takagi, Keiko Tohi, Shin-ichi Maekawa, Akira Miyatake, Aizo Furukawa, Frank J. Gonzalez, Junji Takeda, Yoshiyuki Ichikawa and Yousuke Takahama : T Cell-Specific Disruption of Arylhydrocarbon Receptor Nuclear Translocator (Arnt) Gene Causes Resistance to 2,3,7,8-Tetrachlorodibenzo-p-dioxin-Induced Thymic Involution, The Journal of Immunology, Vol.171, No.8, 4113-4120, 2003.
(Summary)
The arylhydrocarbon receptor nuclear translocator (ARNT) is a member of the basic helix-loop-helix, PER-ARNT-SIM family of heterodimeric transcription factors, and serves as a dimerization partner for arylhydrocarbon receptor (AHR) and hypoxia-inducible factor-1alpha. To assess the function of ARNT in T cells, we disrupted the Arnt gene specifically in T cells of mice by conditional gene targeting using T cell-specific p56(lck)-Cre (Lck-Cre) transgenic Arnt-floxed mice. Thus generated, T cell-specific Arnt-disrupted mice (Lck-Cre;Arnt(flox/Delta) transgenic mice) exhibited complete loss of the expression of ARNT protein only in T cells, and were viable and appeared normal. The Arnt-disrupted T cells in the thymus were phenotypically and histologically normal. The Arnt-deficient T cells in the spleen were capable of responding to TCR stimulation in vitro. However, unlike normal mice in which exposure to the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AHR ligand, resulted in thymic involution, the thymus of Lck-Cre;Arnt(flox/Delta) mice were resistant to TCDD treatment in vivo. In contrast, benzo(a)pyrene, another AHR ligand, still caused thymic involution in Lck-Cre;Arnt(flox/Delta) mice. Finally, fetal thymus organ culture using Lck-Cre;Arnt(flox/Delta) and K5-Cre;Arnt(flox/Delta) (epithelial cell-specific Arnt-disrupted mice) showed that thymocytes rather than thymic epithelial cells are predominantly responsible for TCDD-induced thymic atrophy. Our results indicate that ARNT in T lineage cells is essential for TCDD-mediated thymic involution.
Mariam Nasreen, Tomoo Ueno, Fumi Saito and Yousuke Takahama : In vivo treatment of class II MHC-deficient mice with anti-TCR antibody restores the generation of circulating CD4 T cells and optimal architecture of thymic medulla., The Journal of Immunology, Vol.171, No.7, 3394-3400, 2003.
(Summary)
TCR ligation by the self-peptide-associated MHC molecules is essential for T cell development in the thymus, so that class II MHC-deficient mice do not generate CD4(+)CD8(-) T cells. The present results show that the administration of anti-TCR mAb into class II MHC-deficient mice restores the generation of CD4(+)CD8(-) T cells in vivo. The CD4 T cells were recovered in the thymus, peripheral blood, and the spleen, indicating that the anti-TCR treatment is sufficient for peripheral supply of newly generated CD4 T cells. Unlike peripheral CD4 T cells that disappeared within 5 wk after the treatment, CD4(+)CD8(-) thymocytes remained undiminished even after 5 wk, suggesting that CD4 T cells in the thymus are maintained separately from circulating CD4 T cells and even without class II MHC molecules. It was also found that the mass of medullary region in the thymus, which was reduced in class II MHC-deficient mice, was restored by the anti-TCR administration, suggesting that the medulla for CD4(+)CD8(-) thymocytes is formed independently of the medulla for CD4(-)CD8(+) thymocytes. These results indicate that in vivo anti-TCR treatment in class II MHC-deficient mice restores the generation of circulating CD4 T cells and optimal formation of the medulla in the thymus, suggesting that anti-TCR Ab may be useful for clinical treatment of class II MHC deficiencies.
Hiroshi Nakase, Yousuke Takahama and Yoshiko Akamatsu : Effect of CpG methylation on RAG1/RAG2 reactivity: implications of direct and indirect mechanism for controlling V(D)J cleavage., EMBO Reports, Vol.4, No.8, 774-780, 2003.
(Summary)
It has been suggested that DNA methylation/demethylation is involved in regulating V(D)J rearrangement. Although methylated DNA is thought to induce an inaccessible chromatin structure, it is unclear whether DNA methylation can directly control V(D)J recombination independently of chromatin structure. In this study, we tested whether DNA methylation directly affects the reactivity of the RAG1/RAG2 complex. Specific methylation within the heptamer of the recombination signal sequences (RSS) markedly reduced V(D)J cleavage without inhibiting RAG1/RAG2-DNA complex formation. By contrast, methylation at other positions around the RSS did not affect the reactivity of the RAG proteins. The presence of a methyl-CpG binding-domain protein inhibited the binding of the RAG1/RAG2 complex to all the methylated CpG sites that were tested. Our findings suggest that DNA methylation around the RSS may have a previously unexpected function in regulating V(D)J recombination by directly inhibiting V(D)J cleavage, in addition to its general function of inducing an inaccessible chromatin configuration.
(Keyword)
Animals / Cell Line / DNA Footprinting / DNA Methylation / DNA Nucleotidyltransferases / DNA Primers / DNA-Binding Proteins / Dinucleoside Phosphates / Gene Rearrangement / Genes, Immunoglobulin / Homeodomain Proteins / Humans / Nuclear Proteins / Polymerase Chain Reaction / Receptors, Antigen
Y Akamatsu, R Monroe, DD Dudley, SK Elkin, F Gartner, SR Talukder, Yousuke Takahama, FW Alt, CH Bassing and MA Oettinger : Deletion of the RAG2 C-terminus leads to impaired lymphoid development in mice., Proceedings of the National Academy of Sciences of the United States of America, Vol.100, No.3, 1209-1214, 2003.
(Keyword)
B-CELL DEVELOPMENT / V(D)J RECOMBINATION / PHD FINGER / CORE REGION / TRANSCRIPTION / PROTEINS / GENE / REARRANGEMENT / LOCUS
Tomoo Ueno, Kyoko Hara, Melissa Swope Willis, Mark A. Malin, Uta E. Hoepken, Daniel H.D. Gray, Kouji Matsushima, Martin Lipp, Timothy A. Singer, Richard L. Boyd, Osamu Yoshie and Yousuke Takahama : Role for CCR7 ligands in the emigration of newly generated T lymphocytes from the neonatal thymus., Immunity, Vol.16, No.2, 205-218, 2002.
(Summary)
Most T lymphocytes are generated within the thymus. It is unclear, however, how newly generated T cells relocate out of the thymus to the circulation. The present study shows that a CC chemokine CCL19 attracts mature T cells out of the fetal thymus organ culture. Another CC chemokine CCL21, which shares CCR7 with CCL19 but has a unique C-terminal extension containing positively charged amino acids, failed to show involvement in thymic emigration. Neonatal appearance of circulating T cells was defective in CCL19-neutralized mice as well as in CCR7-deficient mice but not in CCL21-neutralized mice. In the thymus, CCL19 is predominantly localized in the medulla including endothelial venules. These results indicate a CCL19- and CCR7-dependent pathway of thymic emigration, which represents a major pathway of neonatal T cell export.
M Tada, Yousuke Takahama, K Abe, N Nakatsuji and T Tada : Nuclear reprogramming of somatic cells by in vitro hybridization with ES cells., Current Biology, Vol.11, No.19, 1553-1558, 2001.
(Summary)
The resetting of a somatic epigenotype to a totipotential state has been demonstrated by successful animal cloning, via transplantation of somatic nuclei into enucleated oocytes. We have established an experimental system, which reproduces the nuclear reprogramming of somatic cells in vitro by fusing adult thymocytes with embryonic stem (ES) cells. Analysis of the lymphoid-cell-specific V-(D)-J DNA rearrangement of the T cell receptor and immunoglobin genes shows that the ES cells have hybridized with differentiated cells. In these ES cell hybrids, the inactivated X chromosome derived from a female thymocyte adopts some characteristics of an active X chromosome, including early replication timing and unstable Xist transcription. We also found that an Oct4-GFP transgene, which is normally repressed in thymocytes, is reactivated 48 hr after cell fusion. The pluripotency of the ES-thymocyte hybrid cells is shown in vivo, since they contribute to all three primary germ layers of chimeric embryos. The somatic DNA methylation pattern of the imprinted H19 and Igf2r genes is maintained in these hybrids, unlike hybrids between ES and EG (embryonic germ) cells in which the differential methylation is erased. Thus, ES cells have the capacity to reset certain aspects of the epigenotype of somatic cells to those of ES cells.
Shigetoshi Sano, Yousuke Takahama, Takehiko Sugawara, Hiroshi Kosaka, Satoshi Itami, Kunihiko Yoshikawa, Jun-ichi Miyazaki, Willen van Ewijk and Junji Takeda : Stat3 in thymic epithelial cells is essential for postnatal maintenance of thymic architecture and thymocyte survival., Immunity, Vol.15, No.2, 261-273, 2001.
108.
N Masuyama, K Oishi, Y Mori, Tomoo Ueno, Yousuke Takahama and Y Gotoh : Akt inhibits the orphan nuclear receptor Nur77 and T cell apoptosis, The Journal of Biological Chemistry, Vol.276, No.35, 32799-32805, 2001.
(Summary)
Akt is a common mediator of cell survival in a variety of circumstances. Although some candidate Akt targets have been described, the function of Akt is not fully understood, particularly because of the cell type- and context-dependent apoptosis regulation. In this study, we demonstrate that one of the mechanisms by which Akt antagonizes apoptosis involves the inhibition of Nur77, a transcription factor implicated in T-cell receptor-mediated apoptosis. It has been suggested that Akt phosphorylates Nur77 directly, but whether Akt suppresses biological functions of Nur77 remains unknown. We found that Akt inhibited the DNA binding activity of Nur77 and stimulated its association with 14-3-3 in a phosphorylation site-dependent manner. Moreover, we found that expression of Akt suppressed Nur77-induced apoptosis in fibroblasts and activation-induced cell death of T-cell hybridomas. The inhibition of Nur77 by Akt suggests a mechanism that explains how T-cell receptor activation can promote survival in some instances even when Nur77 is induced. Collectively, these results may suggest that Akt is a negative regulator of Nur77 in T-cell apoptosis.
Mirdori Kaneta, Masatake Osawa, Kazuhiro Sudo, Hiromitsu Nakauchi, Andrew G. Farr and Yousuke Takahama : A role for Pref-1 and HES-1 in thymocyte development., The Journal of Immunology, Vol.164, No.1, 256-264, 2000.
110.
Yousuke Takahama, Kazuhito Ohishi, Yayoi Tokoro, Takehiko Sugawara, Yasuhide Yoshimura, Masaru Okabe, Taroh Kinoshita and Junji Takeda : Functional competence of T cells in the absence of glycosylphosphatidylinositol-anchored proteins caused by T cell-specific disruption of the Pig-a gene., Eur. J. Immunol., Vol.28, No.07, 2159-2166, 1998.
111.
T. Sugawara, T. Moriguchi, E. Nishida and Yousuke Takahama : Differential roles of ERK and p38 MAP kinase pathways in positive and negative selection of T lymphocytes., Immunity, Vol.9, 565-574, 1998.
112.
Y. Tokoro, T. Sugawara, H. Yaginuma, H. Nakauchi, C. Terhorst, B. Wang and Yousuke Takahama : A mouse carrying genetic defect in the choice between T and B lymphocytes., The Journal of Immunology, Vol.161, 4591-4598, 1998.
113.
T. Sugawara, V. Bartolo Di, T. Miyazaki, H. Nakauchi, O. Acuto and Yousuke Takahama : An improved retroviral gene transfer technique demonstrates inhibition of CD4-CD8- thymocyte development by kinase-inactive ZAP-70., The Journal of Immunology, Vol.161, 2888-2894, 1998.
114.
S. Sagara, K. Sugaya, Y. Tokoro, S. Tanaka, H. Takano, H. Kodama, T. Nakauchi and Yousuke Takahama : B220 expression by T lymphoid progenitor cells in mouse fetal liver., The Journal of Immunology, Vol.158, No.2, 666-676, 1997.
115.
Yousuke Takahama and Hiromitsu Nakauchi : Phorbol ester and calcium ionophore can replace TCR signals that induce positive selection of CD4 T cells., The Journal of Immunology, Vol.157, No.4, 1508-1513, 1996.
(Summary)
Positive selection of immature thymocytes is a developmental process in which TCR ligation by low avidity interaction induces the generation of mature T cells. However, biochemical signals that can induce positive selection have been unclear. By using TCR-alpha beta- mutant thymus cultures, the present study shows that direct stimulation of intracellular signals by PMA and calcium ionophore ionomycin can induce the generation of mature CD4+8- T cells, bypassing TCR-induced positive selection signals. Interestingly, the concentrations of phorbol ester that induced positive selection were more restricted than those that induced mature T cell activation. Moreover, the combination of phorbol ester and ionomycin restored the generation of CD4+8- T cells in class II MHC- thymus cultures, but did not induce the generation of CD4-8+ T cells in class I MHC- thymus cultures. These results identify that the combination of protein kinase C activation and calcium elevation is the biochemical signal that can induce positive selection of CD4+ T cells.
(Keyword)
Animals / Animals, Newborn / CD4-Positive T-Lymphocytes / CD8-Positive T-Lymphocytes / Cells, Cultured / Clonal Deletion / Enzyme Activation / Histocompatibility Antigens Class I / Histocompatibility Antigens Class II / Ionomycin / Ionophores / Mice / Mice, Knockout / Protein Kinase C / Receptors, Antigen, T-Cell / Receptors, Antigen, T-Cell, alpha-beta / Signal Transduction / Tetradecanoylphorbol Acetate / Thymus Gland
(Link to Search Site for Scientific Articles)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 8759732
Yousuke Takahama, H. Suzuki, S. K. Katz, J. M. Grusby and A. Singer : Positive selection of CD4+ T cells by TCR ligation without aggregation even in the absence of MHC., Nature, Vol.371, No.6492, 67-70, 1994.
(Summary)
The developmental fate of immature thymocytes is determined by the specificity of their T-cell antigen receptors (TCRs). Immature CD4+8+ thymocytes are positively selected to differentiate into mature T cells by recognition of peptides associated with major histocompatibility complex (MHC) encoded molecules on thymic epithelial cells. But neither the identity of molecules transducing positive selection signals nor the nature of the signals themselves is fully known. Here we report that direct ligation of TCR molecules by monoclonal antibodies specific for either clonotypic or CD3 chains can signal immature thymocytes to differentiate into mature CD4+8- T cells, even in the absence of MHC expression and MHC-dependent CD4 co-receptor signalling. Moreover, we show that TCR engagement induces positive selection signals only in the absence of TCR aggregation and that TCR aggregation is inhibitory for positive selection. Thus, low valency of TCR crosslinking is a critical parameter, distinguishing positive selection from other TCR-mediated signalling events.
(Keyword)
Animals / Antibodies, Monoclonal / CD4-Positive T-Lymphocytes / Cell Differentiation / Histocompatibility Antigens Class II / Mice / Organ Culture Techniques / Receptor Aggregation / Receptors, Antigen, T-Cell / Signal Transduction / Thymus Gland
Yousuke Takahama, J. J. Letterio, H. Suzuki, G. A. Farr and A. Singer : Early progression of thymocytes along the CD4/CD8 developmental pathway is regulated by a subset of thymic epithelial cells expressing transforming growth factor β., The Journal of Experimental Medicine, Vol.179, No.5, 1495-1506, 1994.
(Summary)
Precursor cells differentiate into mature CD4+ and CD8+ T cells in the inductive environment of the thymus by undergoing a series of distinct developmental steps marked by expression of the coreceptor molecules CD4 and CD8. Among the earliest cells to enter the CD4/CD8 developmental pathway are CD4-CD8lo precursors cells that differentiate into CD4+CD8+ thymocytes. Here we show that differentiation of precursor cells into CD4+CD8+ thymocytes requires at least one cell division and that their progression through a cell cycle is specifically retarded in the thymus by interaction with thymic epithelial cells that express transforming growth factor beta (TGF-beta) proteins. We also demonstrate that TGF-beta proteins, either in solution or bound to cell membranes, can regulate cell cycle progression and differentiation of CD4-CD8lo precursor cells into CD4+CD8+ thymocytes. The regulatory effect of TGF-beta is specific for CD4-CD8lo precursor cells as TGF-beta proteins do not regulate the earlier generation of CD4-CD8lo precursor cells from CD4-CD8- thymocytes. Finally, we demonstrate that TGF-beta proteins are expressed in vivo in the intact thymus on subcapsular and cortical thymic epithelium where they can contact developing CD4-CD8lo precursor cells. Thus, thymic epithelial cells expressing TGF-beta proteins can actively regulate the rate at which CD4+CD8+ thymocytes are generated from CD4-CD8lo precursor cells.
Yousuke Takahama and Alfred Singer : Research Article: Post-transcriptional regulation of early T cell development by T cell receptor signals., Science, Vol.258, No.5087, 1456-1462, 1992.
(Summary)
During differentiation in the thymus, immature T cells progress through an ordered sequence of developmental stages that are best characterized by variable expression of the co-receptor molecules CD4 and CD8. Crosslinking of T cell receptor (TCR) molecules on precursor thymocytes was found to block their differentiation into CD4+CD8+ cells by eliminating messenger RNA's encoding two families of developmentally important molecules: the co-receptor molecules CD4 and CD8 and the recombination activating genes 1 and 2. TCR-induced post-transcriptional regulation in early thymocytes was specific for selective messenger RNA's, required protein synthesis, and was itself developmentally regulated. These data identify a post-transcriptional mechanism that is influenced by TCR signals and that regulates early thymocyte development.
Yousuke Takahama, Elizabeth W Shores and Alfred Singer : Negative selection of precursor thymocytes before their differentiation into CD4+CD8+ cells., Science, Vol.258, No.5082, 653-656, 1992.
(Summary)
Thymic selection of the developing T cell repertoire is thought to occur at the CD4+CD8+ stage of differentiation and to be determined by the specificity of the T cell receptors (TCRs) that CD4+CD8+ thymocytes express. However, TCR signals can inhibit the differentiation of precursor thymocytes into CD4+CD8+ cells, which suggests that selection might occur earlier than thought. Indeed, in a negatively selecting male thymus, CD4-CD8lo precursor thymocytes that express a transgenic TCR to male antigen are developmentally arrested as a consequence of antigen encounter and fail to become CD4+CD8+. Thus, negative selection can occur before the CD4+CD8+ stage of differentiation.
M Matsuda-Lennikov, Izumi Ohigashi and Yousuke Takahama : Tissue-specific proteasomes in generation of MHC class I peptides and CD8+ T cells, Current Opinion in Immunology, Vol.77, 102217, Aug. 2022.
(Summary)
Thymoproteasomes and immunoproteasomes are two types of tissue-specific proteasomes, which contribute to the production of major histocompatibility complex (MHC) class I (MHC-I)-associated peptides that are important for the development and function of CD8 cytotoxic T cells. Thymoproteasomes are specifically expressed by cortical thymic epithelial cells and are important for MHC-I-dependent positive selection of developing thymocytes, whereas immunoproteasomes are abundant in many other cells, including hematopoietic cells and medullary thymic epithelial cells. Here we summarize the role of these two tissue-specific proteasomes, focusing on their functions in the development of CD8 T cells in the thymus.
Izumi Ohigashi and Yousuke Takahama : Thymoproteasome optimizes positive selection of CD8+ T cells without contribution of negative selection, Advances in Immunology, Vol.149, 1-23, May 2021.
Melina Frantzeskakis, Yousuke Takahama and Izumi Ohigashi : The role of proteasomes in the thymus, Frontiers in Immunology, Vol.12, No.646209, Mar. 2021.
Andrea Cossarizza, (200 authors), Yousuke Takahama and (34 authors) : Guidelines for the use of flow cytometry and cell sorting in immunological studies., European Journal of Immunology, Vol.47, No.10, 1584-1797, Oct. 2017.
(Keyword)
Animals / Cell Proliferation / Cell Separation / DNA / False Positive Reactions / Flow Cytometry / Guidelines as Topic / Humans / Immunologic Techniques / Immunophenotyping / Quality Control / RNA / Research Design / Software / T-Lymphocytes
Yousuke Takahama, Izumi Ohigashi, Song Baik and Graham Anderson : Generation of diversity in thymic epithelial cells, Nature Reviews. Immunology, Vol.17, No.5, 295-305, May 2017.
(Summary)
In the thymus, diverse populations of thymic epithelial cells (TECs), including cortical and medullary TECs and their subpopulations, have distinct roles in coordinating the development and repertoire selection of functionally competent and self-tolerant T cells. Here, we review the expanding diversity in TEC subpopulations in relation to their functions in T cell development and selection as well as their origins and development.
Naoko Matsui, Takeshi Nitta and Yousuke Takahama : Development of the thymus and immune system, Brain and Nerve = Shinkei kenkyū no shinpo, Vol.63, No.7, 679-684, Jul. 2011.
(Summary)
A repertoire of T cells is primarily formed in the thymus through positive and negative selection of developing thymocytes. The medullary region of the thymus provides a microenvironment that is essential for the establishment of self-tolerance via the depletion of self-reactive T cells and the production of regulatory T cells. Within the medullary microenvironment, medullary thymic epithelial cells play a pivotal role in the establishment of self-tolerance, via the promiscuous expression of tissue-restricted self-antigens and the chemokine-mediated attraction of positively selected T cells from the cortex to the medulla. Positive selection also induces the expression of TNF-superfamily cytokines and thereby nurtures the growth and development of medullary thymic epithelial cells. We will review the mechanisms of how the thymus contributes to the development and selection of T cells, with emphasis on the establishment of self-tolerance in the thymic medulla.
(Keyword)
T cell repertoire / self-tolerance / thymic microenvironment / medullary thymic epithelial cells / regulatory T cells
(Link to Search Site for Scientific Articles)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 21747137
Takeshi Nitta and Yousuke Takahama : CD8+ T細胞のレパートリー形成と胸腺プロテアソーム, 臨床免疫・アレルギー科, 2010.
26.
Takeshi Nitta, Tomoo Ueno and Yousuke Takahama : Cytokines and chemokines that regulate the microenvironment of the thymic medulla, Experimental Medicine, Vol.27, No.11, 1764-1769, Jul. 2009.
Sayumi Fujimori, Shinji Takada, Yousuke Takahama and Izumi Ohigashi : Role of β-catenin in mouse thymic epithelial cells for postnatal thymic development, The 18th International Symposium of the Institute Network for Biomedical Sciences, Oct. 2023.
2.
Sayumi Fujimori, Shinji Takada, Yousuke Takahama and Izumi Ohigashi : Role of β-catenin in thymic epithelial cells for postnatal thymic development and involution, ThymOz International Conference on T Cells: ThymOz 2023, Mar. 2023.
3.
Izumi Ohigashi, White J. Andrea, Yang Mei-Ting, Sayumi Fujimori, Anderson Graham and Yousuke Takahama : Developmental conversion of thymocyte-attracting cells into self-antigen-displaying cells in thymus medulla epithelium, ThymOz International Conference on T Cells: ThymOz 2023, Mar. 2023.
4.
Izumi Ohigashi, Yu Tanaka, Kenta Kondou, Sayumi Fujimori, Amy C. Palin, Hiroyuki Kondo, Hidetaka Kosako and Yousuke Takahama : Trans-omics impact of thymoproteasome in cortical thymic epithelial cells, ThymE: T cell and thymus biology, May 2019.
5.
Izumi Ohigashi and Yousuke Takahama : Human PSMB11 polymorphisms that affect thymoproteasome processing and CD8+ T cell generation, 8th THYMOZ, Mar. 2018.
6.
Uddin Myn, Izumi Ohigashi and Yousuke Takahama : Foxn1-b5t transcriptional axis controls CD8+ T-cell production in the thymus, IMMUNOLOGY 2017, AAI Annual Meeting, May 2017.
7.
Yousuke Takahama : Mechanisms for positive selection of CD8+ T cells, 2017 FIMSA Advanced Course, Apr. 2017.
8.
Yousuke Takahama : cTEC-dependent positive selection of CD8+ T cells, 7th International Workshop of Kyoto T Cell Conference, Mar. 2017.
9.
Kondo Hiroyuki, Izumi Ohigashi, Kozai Mina, Kubo Yuki, Katakai Tomoya, Luther A. Sanjiv and Yousuke Takahama : Essential role of CCL21 in establishment of central self-tolerance in T cells, 7th International Workshop of Kyoto T Cell Conference, Mar. 2017.
10.
Izumi Ohigashi, Ohte Yuki, Setoh Kazuya, Matsuda Fumihiko, Murata Shigeo and Yousuke Takahama : A human Psmb11 polymorphism affects molecular processing of thymoproteasome and thymic production of CD8+ T cells, 7th International Workshop of Kyoto T Cell Conference, Mar. 2017.
11.
Sayumi Fujimori, Izumi Ohigashi, Tatsuya Takemoto, Yousuke Takahama and Takada Shinji : Activation of Wnt/β-catenin signaling in thymic epithelial progenitors, 7th International Workshop of Kyoto T Cell Conference, Kyoto, Mar. 2017.
12.
Kozai Mina, Izumi Ohigashi and Yousuke Takahama : CCL21 regulates T-cell self-tolerance in thymic medulla, 11th International Symposium of The Institute Network Frontiers in Biomedical Sciences, Jan. 2017.
13.
Izumi Ohigashi, Uddin Myn, Tatsuya Takemoto and Yousuke Takahama : Foxn1-binding cis-regulatory element required for optimal CD8+ T cell production in the thymus, 11th International Symposium of The Institute Network Frontiers in Biomedical Sciences, Jan. 2017.
14.
Yousuke Takahama : How the thymic medulla attracts thymocytes for the establishment of selftolerance, 2016 NCI Thymus Symposium, Dec. 2016.
15.
Yousuke Takahama : T-cell development & selection, The 13th FIMSA Advanced Immunology Course, チャンディーガール(インド), Mar. 2016.
16.
Izumi Ohigashi and Yousuke Takahama : Foxn1-binding cis-regulatory element required for optimal CD8+ T cell production in the thymus, The Fifth Bizan Immunology symposium, 徳島県徳島市, Mar. 2016.
17.
Yousuke Takahama : T cell formation in thymus microenvironments, Asia CORD 2015 in KOBE, 神戸市, May 2015.
18.
Yousuke Takahama : Thymus epithelium conditions antigen responsiveness in CD8+T cells, 1st international Venice Thymus Meeting, Apr. 2015.
19.
Yousuke Takahama : Synthetic immunology, The 1st meeting of Thymus Translational Research, 下高井郡, Feb. 2015.
20.
Izumi Ohigashi and Yousuke Takahama : Adult thymus medullary epithelium is maintained and regenerated by lineage restricted cells rather than bipotent progenitors, The Fourth BIZAN Immunology Symposium at University of TokushimaImmune System Development, Deviation, and Regulation, Jan. 2015.
21.
Yousuke Takahama : Positive selection conditions TCR responsiveness in T cells, The Fourth BIZAN Immunology Symposium at University of TokushimaImmune System Development, Deviation, and Regulation, Jan. 2015.
22.
Kensuke Takada and Yousuke Takahama : Thymoproteasome-dependent MHC class I-associated peptide motifs contribute to positive selection of CD8 T cells, The 24th Hot Spring Harbor International Symposium Recent Advance in Immunology and Inflammation, Nov. 2014.
23.
Kensuke Takada and Yousuke Takahama : Positive selection conditions antigen responsiveness of CD8 T cells, The 7th ThymOZ International Conference, Apr. 2014.
24.
Izumi Ohigashi, Zuklys Saulius, Hollander Georg and Yousuke Takahama : mTECs derived from embryonic and postnatal beta5t+ progenitors, The 7th ThymOZ International Conference, Apr. 2014.
25.
Yousuke Takahama : Thymus microenvironments for T cell repertoire formation, The 1st international Nano.BioMedical conference, Feb. 2014.
26.
Izumi Ohigashi and Yousuke Takahama : Development and developmental potential of 5t-expressing thymic epithelial cells, The Third Bizan Immunology Symposium at The University of Tokushima (BISUT3) "Immune System Development, Deviation, and Regulation", Feb. 2014.
27.
Kensuke Takada and Yousuke Takahama : What is the positive selection for?, The Third Bizan Immunology Symposium at The University of Tokushima (BISUT3) "Immune System Development, Deviation, and Regulation", Feb. 2014.
28.
Taisuke Nakayama, Hirotsugu Kurobe, Noriko Sugasawa, Hajime Kinoshita, Yasushi Yoshida, Yoichiro Hirata, Mie Sakata, Mark Webster Maxfield, Michio Shimabukuro, Yousuke Takahama, Masataka Sata, Toshiaki Tamaki, Tetsuya Kitagawa and Shuhei Tomita : Macrophage-Specific Hypoxia-Inducible Factor (HIF)-1-Deficient Mice Suppress the Vascular Remodeling and Regulate M2 Macrophage Polarization, American Heart Association AHA 2013, Nov. 2013.
29.
Yousuke Takahama and Izumi Ohigashi : Serial development of cortical and medullary thymic epithelia, Fourth Synthetic Immunology WorkshopEngineering in Immunity, Nov. 2013.
30.
Yousuke Takahama : The thymic microenvironments that shape T cell repertoire, 15th International Congress of Immunology, Aug. 2013.
31.
Kensuke Takada and Yousuke Takahama : Functional conditioning of CD8 T cells by thymoproteasome-dependent positive selection., 6th International Workshop of Kyoto T Cell Conference, Kyoto, Jul. 2013.
Yousuke Takahama and Izumi Ohigashi : Development and developmental potential of 5t-expressing thymic epithelial cells, KTCC 2013 International Workshop on T Lymphocytes, Jun. 2013.
34.
Kensuke Takada and Yousuke Takahama : Functional conditioning of CD8 T cells by thymoproteasome-dependent positive selection, KTCC 2013 International Workshop on T Lymphocytes, Jun. 2013.
35.
Lkhagvasuren Enkhsaikhan, Sakata Mie, Izumi Ohigashi and Yousuke Takahama : Lymphotoxin receptor regulates the development of CCL21-expressing subset of postnatal medullary thymic epithelial cells, KTCC 2013 International Workshop on T Lymphocytes, Jun. 2013.
36.
Manley R Nancy, Li Jie, Timmons Cullen, Yousuke Takahama and Sornborger Andrew : CASA: A new method for quantifying tissue organization, KTCC 2013 International Workshop on T Lymphocytes, Jun. 2013.
37.
Kensuke Takada and Yousuke Takahama : Functional conditioning of CD8 T cells by thymoproteasome-dependent positive selection., 100th American Association of Immunologists Annual Meeting, May 2013.
38.
Yousuke Takahama : Attacking the endocrine system: what is AIRE doing?, Society for Endocrinology BES 2013, Mar. 2013.
39.
Kensuke Takada and Yousuke Takahama : Thymoproteasome-dependent positive selection conditions cytokine reactivity of mature CD8 T cells., The Second Immunology Symposium of The University of Tokushima Immune System Development, Deviation, and Regulation, Jan. 2013.
40.
Yousuke Takahama : Development and developmental potential of cTECs, The Second Immunology Symposium of The University of TokushimaImmune Development, Deviation, and Regulation, Jan. 2013.
41.
Yousuke Takahama : Thymic microenvironments for T cell repertoire formation, Centennial of Hashimoto Disease International Symposium, Dec. 2012.
42.
Takai C., Yasushi Nakagawa, Kazuya Kondo and Yousuke Takahama : Microarray analysis for CD classification of thymic epithelial cell subpopulations, 3rd International Thymic Malignancy Interest Group Annual Meeting, Nov. 2012.
43.
Yousuke Takahama : T cell repertoire formation in the thymus, 3rd International Thymic Malignancy Interest Group Annual Meeting, Nov. 2012.
44.
Taisuke Nakayama, Hirotsugu Kurobe, Noriko Sugasawa, Hajime Kinoshita, Mayuko Higashida, Yuki Matsuoka, Yasushi Yoshida, Yoichiro Hirata, Mie Sakata, Mark Webster Maxfield, Yousuke Takahama, Masataka Sata, Toshiaki Tamaki, Tetsuya Kitagawa and Shuhei Tomita : Role of Macrophage-derived Hif-1a as a Mediator of Vascular Remodeling, American Heart Association Scientific Sessions 2012, Nov. 2012.
45.
Naoko Matsui, Izumi Ohigashi, Kazuya Kondo, Nomura Yoshiko, Yousuke Takahama and Ryuji Kaji : Increased Hassalls Corpuscles In Myasthenia Gravis Patients Carrying Thymic Hyperplasia, 11th International congress of neuroimmunology, Nov. 2012.
46.
Yousuke Takahama : Aire+ thymic medullary epithelial cells originate from beta 5t+ progenitor cells, ThymUS International Conference, Nov. 2012.
47.
Enkhsaikhan Lkhagvasuren and Yousuke Takahama : Heterogenesity in medullary thymic epithelial cells A2147G is the most prevalent mutation among clarithromycin resistant, 3rd International Conference Advances in Microbiology and Immunology, ウランバートル, Jun. 2012.
48.
Yousuke Takahama : T lymphocyte repertoire formation in thymic microenvironments, 3rd International Conference Advances in Microbiology and Immunology, ウランバートル, Jun. 2012.
49.
Michiyuki Kasai and Yousuke Takahama : Towards the establishment of functionally competent thymic epithelial cell lines, The 3rd Workshop of Synthetic Immunology 2012, 11, May 2012.
Michiyuki Kasai and Yousuke Takahama : TOWARDS THE ESTABLISHMENT OF FUNCTIONALLY COMPETENT THYMIC EPITHELIAL CELL LINES, The 3rd Workshop of Synthetic Immunology, Kyoto, May 2012.
51.
Yousuke Takahama : The thymic cortex and positive selection of T cells, Thymus Symposium, May 2012.
52.
Yousuke Takahama : Thymic cortical epithelial cells for T cell repertoire formation, The 99th AAI Annual Meeting IMMUNOLOGY, Boston, May 2012.
53.
Kensuke Takada and Yousuke Takahama : Functional abnormality of peripheral CD8 T cells in beta5t-deficient mice, The 99th American Association of Immunologists Annual Meeting, May 2012.
54.
Kensuke Takada and Yousuke Takahama : Functional abnormality of peripheral CD8 T cells in β5t-deficient mice, The 99th AAI Annual Meeting IMMUNOLOGY, Boston, May 2012.
55.
Hirotsugu Kurobe, takashi Tominaga, Masahisa Urata, Mikio Sugano, Yoichiro Hirata, Miho Sakata, Yasunobu Hayabuchi, Takashi Kitaichi, Takaki Hori, Yoshiyasu Egawa, Yousuke Takahama and Tetsuya Kitagawa : Complete thymectomy during cardiac surgery in early infancy reduces circulating T cells and vaccination-induced IgG responses: a study of 3-year-tracing, AATS2012 92th annual meeting, San Francisco, Apr. 2012.
56.
Yousuke Takahama : T lymphocyte repertoire formation in thymic microenvironments, FIMSA 2012, Mar. 2012.
57.
Yousuke Takahama : Thymic microenvironment and repertoire selection of T cells, New Horizons in the Immune System, Feb. 2012.
58.
Yousuke Takahama : Molecular Biology of Thymic Microenvironments, The 2011 CSI/FIMSA (3rd CSI) Advanced Course on Immunology, Dec. 2011.
59.
Kensuke Takada and Yousuke Takahama : Memory-like phenotype of CD8 T cells in 5t-deficient mice, EUThyme-Rolduc Meeting, May 2011.
60.
Yousuke Takahama : Cytokine circuit that regulates T cell repertoire formation, JSICR-MMCB2011, Osaka, May 2011.
61.
Saulius Zuklys, E. Carlos Mayer, Saule Zhanybekova, Takeshi Nitta, Stephan Chappaz, Yousuke Takahama, Daniela Finke and A. Georg Holländer : Dicer-dependent miRNA are required for the postnatal maintenance of the thymic epithelial microenvironment, EUThyme-Rolduc Meeting, May 2011.
62.
Yousuke Takahama : Chemokine regulation of central tolerance, EUThyme-Rolduc Meeting, May 2011.
63.
Graham Anderson, Natalie Roberts, Andrea White, William Jenkinson, David Withers, Gleb Turchinovich, Adrian Hayday, Josef Penninger, Takeshi Nitta, Yousuke Takahama, Peter Lane and Eric Jenkinson : Maturation Of Intrathymic Dendritic Epidermal T-cell Progenitors And Aire-Expressing Medullary Epithelial Cells Are Reciprocally Linked, EUThyme-Rolduc Meeting, May 2011.
64.
Yousuke Takahama : Mechanisms to establish self-tolerance in the thymic medulla, Lymphocyte development and autoimmunity, CHIP meeting, Lund(Sweden), Mar. 2011.
65.
Yousuke Takahama : Thymic microenvironments that shape T lymphocyte repertoire, ESF-JSPS Frontier Science Conference for Young Researchers Cutting Edge Immunology and its Clinical Application, Hulshort(The Netherlands), Mar. 2011.
66.
Izumi Ohigashi, Takeshi Nitta, ENOMOTO Tetsuro, TOMIMORI Toshiya, YASUDA Hisataka and Yousuke Takahama : RANKL PROMOTES THYMIC MEDULLA FORMATION, The 2nd Workshop of Synthetic Immunology, Kyoto, Dec. 2010.
67.
Yousuke Takahama : T-CELL REPERTOIRE FORMATION IN THE THYMUS, Cold Spring Harbor Asia Conferences -Frontiers of Immunology in Health and Diseases-, Suzhou(China), Nov. 2010.
68.
Yousuke Takahama : Thymic microenvironments shaping T-cell repertoire, 8th German-Japanese Symposium on Regulation of Immune Response and Disease, Cuxhaven(Germany), Sep. 2010.
69.
Naozumi Ishimaru, Akiko Yamada, Rieko Arakaki, Yousuke Takahama and Yoshio Hayashi : Critical Signaling Pathway via CCR7 of Foxp3+CD25+CD4+ Regulatory T Cells for the Egress from Lymph Nodes, international immunology, Aug. 2010.
70.
Takeshi Nitta, Sachiko Nitta and Yousuke Takahama : Role of cortical thymic epithelial cells in positive selection of T cells., 14th International Congress of Immunology, Kobe, Aug. 2010.
71.
Naozumi Ishimaru, Akiko Yamada, Rieko Arakaki, Yousuke Takahama and Yoshio Hayashi : Critical signaling pathway via CCR7 of Foxp3+CD25+CD4+ regulatory T cells for the egress from lymph nodes., 第14回国際免疫学会, Kobe, Aug. 2010.
72.
Hirotsugu Kurobe, Takashi Tominaga, Mikio Sugano, Masahisa Urata, Takaki Hori, Yoshiyasu Egawa, Yousuke Takahama and Tetsuya Kitagawa : Complete thymectomy at neonatal cardiac surgery reduces circulating T cells, 14th International Congress of Immunology 2010, Kobe, Aug. 2010.
73.
Matsui Naoko, Nakane Shunya and Yousuke Takahama : Undiminished Regulatory T Cells in the Thymus of Myasthenia Gravis Patients, 14th International Congress of Immunology, Kobe, Aug. 2010.
74.
Zuklys Saulius, E Carlos, Zhanybekova Saule Mayer, Takeshi Nitta, Chappaz Stephan, Gill Jason, Yousuke Takahama, Finke Daniela and Holländer A. Georg : Dicer is required for the postnatal maintenance of the thymic epithelial microenvironment, 14th International Congress of Immunology, Kobe, Aug. 2010.
75.
Lei Yu, Takeshi Nitta, Ripen Mat Adiratna, Malefyt de Waal Rene and Yousuke Takahama : Aire regulates XCL1-mediated medullary accumulation of thymic dendritic cells and thymic development of regulatory T cells, 14th International Congress of Immunology, Kobe, Aug. 2010.
76.
Yousuke Takahama : Thymic microenvironments that shape T cell repertoire, 14th International Congress of Immunology, Kobe, Aug. 2010.
77.
Yousuke Takahama : XCL1 regulates medullary accumulation of thymic dendritic cells and thymic development of regulatory T cells, Gordon Research Conferences, Lucca(Italy), Jun. 2010.
78.
Takeshi Nitta, Shigeo Murata, Katsuhiro Sasaki, Hideki Fujii, Shigeo Koyasu, Keiji Tanaka and Yousuke Takahama : Thymoproteasome shapes immunocompetent repertoire of CD8+ T cells, ThymOz International Conference, Gladstone, Queensland, Australia, Mar. 2010.
79.
Takeshi Nitta, Sachiko Nitta and Yousuke Takahama : Revisiting thymic nurse cell, The 5th International Workshop of Kyoto T Cell Conference 2009, Kyoto, Japan, Jun. 2009.
80.
Takeshi Nitta, Yu Hikosaka and Yousuke Takahama : RANKL produced by positively selected thymocytes fosters Aire+ mTEC, ThymUS 2008 International Conference, San Juan, Puerto Rico, USA, Nov. 2008.
81.
Takeshi Nitta and Yousuke Takahama : IAN5 regulates T-cell survival, ThymOz International Workshop on T Lymphocytes, Heron Island, Australia, Apr. 2006.
82.
Takeshi Nitta, Mariam Nasreen, Takafumi Seike, Atsushi Goji and Yousuke Takahama : IAN family critically regulates T lymphocyte development, ThymuS 2004, San Juan, Puerto Rico, USA, Nov. 2004.
83.
Hiroko Hagiwara, Kazumi Sawakami, Midori Yamamoto, Hideji Tajima, Shouji Iwasaki, Masato Kobori, Mitsuo Itakura, Yousuke Takahama and Masayuki Machida : Development of an automated system for the analysis of SNPs using the MagtrationR technology, 6. Genome Sequencing and Analysis Conference, San Diego, 2001.
Proceeding of Domestic Conference:
1.
Izumi Ohigashi, White J. Andrea, Yang Mei-Ting, Sayumi Fujimori, Anderson Graham and Yousuke Takahama : ケモカインCCL21を発現する胎仔期の胸腺髄質上皮細胞は自己抗原発現髄質上皮細胞への分化活性を有する, 第46回日本分子生物学会年会, Dec. 2023.
2.
Aya Ushio, 松田 真美, Naozumi Ishimaru and Yousuke Takahama : 機能的に異なる髄質胸腺上皮サブセットが中枢性自己寛容確立にもたらす相互作用, 第69回日本病理学会秋期特別総会, Nov. 2023.
3.
Aya Ushio, 松田 真美, Naozumi Ishimaru and Yousuke Takahama : 中枢性自己寛容確立に関わる機能的に異なる髄質胸腺上皮サブセットの相互作用, 第65回歯科基礎医学会学術大会, Sep. 2023.
4.
Izumi Ohigashi, J. Andrea White, Mei-Ting Yang, Sayumi Fujimori, Grahama Anderson and Yousuke Takahama : ケモカインCCL21を発現する胸腺髄質上皮細胞は自己抗原発現髄質上皮細胞への分化活性を有する, 第32回 Kyoto T Cell Conference, Jun. 2023.
5.
Aya Ushio, 松田-Lennikov 真実, Kunihiro Otsuka, Takaaki Tsunematsu, Naozumi Ishimaru and Yousuke Takahama : 自己免疫疾患発症における多様性胸腺髄質上皮細胞の相乗的制御機構, 第112回日本病理学会総会, Apr. 2023.
6.
Izumi Ohigashi, Frantzeskakis Melina and Yousuke Takahama : The thymoproteasome hardwires the TCR repertoire of CD8+ T cells in the cortex independent of negative selection, 第45回日本分子生物学会年会, Nov. 2022.
7.
Sayumi Fujimori, Izumi Ohigashi, Yousuke Takahama and 高田 慎治 : Fine-tuning of beta-catenin in mouse thymic epithelial cells is required for postnatal T-cell development, 第45回日本分子生物学会年会, Nov. 2022.
8.
Sayumi Fujimori, Yousuke Takahama, 高田 慎治 and Izumi Ohigashi : 出生後T細胞の産生における胸腺上皮細胞のβ-cateninの役割, 第31回Kyoto T Cell Conference(KTCC), May 2022.
9.
Izumi Ohigashi, Hidetaka Kosako and Yousuke Takahama : Trans-omics impact of thymoproteasome in cortical thymic epithelial cells, 第42回日本分子生物学会年会, Dec. 2019.
10.
Sayumi Fujimori, Izumi Ohigashi, Yousuke Takahama and 高田 慎治 : Fine-tuning of the β-catenin-dependent signaling in mouse thymic epithelial cells is required for thymic development, 第42回日本分子生物学会年会, Dec. 2019.
Sayumi Fujimori, Izumi Ohigashi, Takada Shinji and Yousuke Takahama : Enforced activation of β-catenin signaling in mouse thymic epithelial cells induces thymic dysplasia, The 41st Annual Meeting of the Molecular Biology Society of Japan, Nov. 2018.
14.
Yamamoto Yohhei, Naoko Matsui, Kazuya Kondo, Izumi Ohigashi, Yousuke Takahama, Nakagawa Hidewaki, Yuishin Izumi and Ryuji Kaji : Analysis of human thymic epithelial cells, 第59回日本神経学会学術大会, May 2018.
15.
Izumi Ohigashi, Naozumi Ishimaru, Katakai Tomoya and Yousuke Takahama : Essential role of CCL21 in establishment of central tolerance in T cells, 第40回 日本分子生物学会年会, Dec. 2017.
Naoko Matsui, Izumi Ohigashi, Yamamoto Yohei, Kazuya Kondo, Yousuke Takahama and Ryuji Kaji : Approach for analysis of human thymic epithelial cells, XX World Congress of Neurology, Sep. 2017.
19.
Uddin Myn, Izumi Ohigashi and Yousuke Takahama : Foxn1-binding cis-regulatory element required for optimal CD8+ T cell production in the thymus, 第46回日本免疫学会学術集会, Dec. 2016.
金 喜栄, Naoko Matsui, Izumi Ohigashi, 古川 貴大, Yousuke Takahama and Ryuji Kaji : ヒト胸腺を用いた胸腺上皮細胞解析への試み, 第57日本神経学会学術大会, 367, May 2016.
24.
Myn Uddin, Izumi Ohigashi and Yousuke Takahama : Foxn1-binding cis-regulatory element for optimal CD8+ T cell production in the thymus, 第26回 Kyoto T cell Conference, May 2016.
25.
Kensuke Takada and Yousuke Takahama : 次世代シーケンサを用いた胸腺プロテアソーム欠損マウスCD8T細胞のレパトア解析, 第26回 Kyoto T Cell Conference, May 2016.
Bongju Kim, Izumi Ohigashi and Yousuke Takahama : Role of mitochondria in thymic epithelial cells, 第43回日本免疫学会学術集会, Dec. 2014.
37.
Bongju Kim, Izumi Ohigashi and Yousuke Takahama : Role of mitochondria in thymic epithelial cells, 第43回日本免疫学会学術集会, Dec. 2014.
38.
Izumi Ohigashi and Yousuke Takahama : 5t+ progenitors contribute to the maintenance and regeneration of medullary thymic epithelial cells, 第43回日本免疫学会学術集会, Dec. 2014.
39.
Yousuke Takahama : Thymus microenvironment for the formation of CD8 T cell repertoire, 第43回日本免疫学会学術集会, Dec. 2014.
40.
Kensuke Takada and Yousuke Takahama : Thymoproteasome-dependent positive selection conditions antigen responsiveness of CD8 T cells, 第43回日本免疫学会学術集会, Dec. 2014.
41.
香西 美奈, Izumi Ohigashi and Yousuke Takahama : Defective T cell tolerance in CCL21 knockout mice, 第43回日本免疫学会学術集会, Dec. 2014.
42.
Yousuke Takahama : Thymus microenvironment for the formation of CD8 T cell repertoire, 第43回日本免疫学会学術集会, Dec. 2014.
43.
Kensuke Takada and Yousuke Takahama : 正の選択を介して決定されるCD8T細胞の抗原応答性, 第157回日本獣医学会学術集会, Sep. 2014.
Izumi Ohigashi and Yousuke Takahama : 髄質上皮細胞の維持と再生におけるβ5t陽性前駆細胞の寄与, 第24回 Kyoto T Cell Conference, May 2014.
47.
Kensuke Takada, Nhi Ngoc Le, 佐々木 克博, 村田 茂穂 and Yousuke Takahama : 胸腺プロテアソーム依存的に産生される自己ペプチドの正の選択における特性, 第24回 Kyoto T Cell Conference, May 2014.
48.
Yousuke Takahama : T cell repertoire formation in the thymus, The 3rd NIF Winter School on Advanced Immunology, Jan. 2014.
49.
Yousuke Takahama : Tリンパ球レパトアを形成する胸腺微小環境, 大阪大学微生物研究所 Advanced Seminar Series on Microbiology and Immunology, Jan. 2014.
50.
Izumi Ohigashi and Yousuke Takahama : Development and developmental potential of5t-expressing thymic epithelial cells, 第42回日本免疫学会学術集会, Dec. 2013.
51.
Kensuke Takada and Yousuke Takahama : Functional conditioning of CD8 T cells by thymoproteasome-dependent positive selectio, 第42回日本免疫学会学術集会, Dec. 2013.
52.
Yousuke Takahama : Immune cells need stromal cells to work, 第42回日本免疫学会学術集会, Dec. 2013.
Izumi Ohigashi and Yousuke Takahama : 胸腺皮質上皮細胞特異的β5tおよび髄質上皮細胞に発現するCCL21aの発現トレーサー実験による胸腺上皮細胞分化機構の解析, 第37回日本リンパ学会総会, Jun. 2013.
55.
T Nakayama, Hirotsugu Kurobe, H Sugasawa, Hajime Kinoshita, M Higashida, Y Matsuoka, Y Yoshida, Y Hirata, M Sakata, Yousuke Takahama, Masataka Sata, Toshiaki Tamaki, Tetsuya Kitagawa and Shuhei Tomita : Macrophage-specific HIF-1a-deficient Mice Suppress Vascular Remodeling., 第77回 日本循環器学会学術集会, Mar. 2013.
矢野 弘太 and Yousuke Takahama : Mouse IAN4/Gimap3 encodes a functional melecule that regulate cellularity of T cells, 第41回日本免疫学会学術集会, Dec. 2012.
61.
Kensuke Takada and Yousuke Takahama : Functional abnormality of peripheral CD8 T cells in beta 5t-deficient mice, 第41回日本免疫学会学術集会, Dec. 2012.
62.
Naoko Matsui, Izumi Ohigashi and Yousuke Takahama : Increased Hassalls corpuscles in myasthenia gravis patients carrying thymic hyperplasia, 41st Annual Meeting of The Japanese Society for Immunology, Dec. 2012.
Lkhagvasuren Enkhsaikhan and Yousuke Takahama : Autoimmune regulator and lymphotoxin beta receptor affect the development of CCL21-producing medullary thymic epithelial cell, 第41回日本免疫学会学術集会, Dec. 2012.
66.
Izumi Ohigashi and Yousuke Takahama : Analysis of cortical and medullary bifurcation mechanisms in thymic epithelial cells using cortical thymic epithelial cell-specific beta 5t-Cre knock-in mice, 第41回日本免疫学会学術集会, Dec. 2012.
67.
Yasushi Nakagawa and Yousuke Takahama : Microarray analysis for CD classification of thymic epithelial cell subpopulations, 第41回日本免疫学会学術集会, Dec. 2012.
Kensuke Takada and Yousuke Takahama : β5t欠損マウスにおける末梢CD8T細胞の機能異常, 第21回 Kyoto T Cell Conference, Jul. 2012.
73.
Izumi Ohigashi and Yousuke Takahama : 胸腺皮質上皮細胞特異的b5t遺伝子座にCreをノックインしたマウスの作製, 第22回 Kyoto T Cell Conference, Jul. 2012.
74.
Lkhagvasuren Enkhsaikhan and Yousuke Takahama : Molecular heterogeneity in medullary thymic epithelial cells, 第11回四国免疫フォーラム, Jun. 2012.
75.
Taisuke Nakayama, Hirotsugu Kurobe, Noriko Sugasawa, Hajime Kinoshita, Mayuko Higashida, Yuuki Matsuoka, Mitsuru Takaku, Yasushi Yoshida, Yoichiro Hirata, Yousuke Takahama, Masataka Sata, Toshiaki Tamaki, Tetsuya Kitagawa and Shuhei Tomita : Role of Hypoxia-Inducible Factor1-alpha in Macrophage as an Aggravation Regulator in Development of Vascular Remodeling., 第76回 日本循環器学会学術集会, Mar. 2012.
Michiyuki Kasai, Yousuke Takahama and Udono Heiichirho : Expression profiles of beta5 subunits in thymic epithelial cell lines, Proceedings of the Japanese Society for Immunology, Vol.40, 216, Nov. 2011.
Kensuke Takada and Yousuke Takahama : Analysis of peripheral CD8 T cells in 5t-deficient mice, 第40回日本免疫学会学術集会, Nov. 2011.
79.
Yasushi Nakagawa and Yousuke Takahama : マウス胸腺上皮細胞のマイクロアレイ解析によるヒト胸腺解析法開発の試み, 第40回日本免疫学会学術集会, Nov. 2011.
80.
Takeshi Nitta, Izumi Ohigashi, Yasushi Nakagawa and Yousuke Takahama : Lympho-epithelial complexes in the thymic cortex, 第40回日本免疫学会学術集会, Nov. 2011.
81.
Kouta YANO and Yousuke Takahama : IAN4 and IAN5 critically regulates TCR-mediated survival of T cells, 第40回日本免疫学会学術集会, Nov. 2011.
82.
Izumi Ohigashi and Yousuke Takahama : Identification of the transgenic integration site in immunodeficient tgε26 human CD3ε transgenic mice, 第40回日本免疫学会学術集会, Nov. 2011.
83.
笠井 道之, 鵜殿 平一郎 and Yousuke Takahama : Expression profiles of beta5 subunits in thymic epithelial cell lines, 第40回日本免疫学会学術集会, Nov. 2011.
Hirotsugu Kurobe, Takashi Tominaga, Masahisa URATA, Mikio Sugano, Takashi Kitaichi, Tomohisa Kawahito, Takaki Hori, Yoshiyasu Egawa, Yousuke Takahama and Tetsuya Kitagawa : The post-operative problem in the infants with total thymectomy, and its management., the 63rd Annual Scientific Meeting of the Japanese Association for Thoracic Surgery, Oct. 2010.
Kensuke Takada, Takeshi Nitta and Yousuke Takahama : 胸腺プロテアソーム構成因子β5t非依存的に分化したCD8T細胞の抗原特異性, 第20回Kyoto T Cell Conference, Jun. 2010.
95.
Lei Yu, Ripen Mat Adiratna, Takeshi Nitta and Yousuke Takahama : Aire regulates XCL1-mediated medullary accumulation of thymic dendritic cells and thymic development of regulatory T cells, 第20回Kyoto T Cell Conference, Jun. 2010.
96.
Takeshi Nitta, 新田 幸子, Yasushi Nakagawa and Yousuke Takahama : T細胞レパトア選択における胸腺皮質上皮細胞の役割, 第20回 Kyoto T Cell Conference, Jun. 2010.
Takeshi Nitta and Yousuke Takahama : 胸腺クロストークによるT細胞レパトア形成の制御, 第32回日本分子生物学会年会, Dec. 2009.
100.
Takeshi Nitta, 村田 茂穂, 藤猪 英樹, 小安 重夫, 田中 啓二 and Yousuke Takahama : The thymoproteasome generates immunocompetent repertoire of CD8 T cells, 第39回 日本免疫学会総会・学術集会, Dec. 2009.
101.
Naozumi Ishimaru, Rieko Arakaki, Akiko Yamada, Yousuke Takahama and Yoshio Hayashi : In situ patrolling of regulatory T cells is essential for protecting organ-specific autoimmunity, 日本免疫学会総会・学術集会, Dec. 2009.
Takeshi Nitta, 郷司 敦史, 宮崎 忠昭 and Yousuke Takahama : IAN family proteins regulate development and survival of T lymphocytes, 第36回 日本免疫学会総会・学術集会, Dec. 2006.
Takeshi Nitta, 劉 村蘭, 斉藤 ふみ and Yousuke Takahama : 胸腺細胞の髄質移動と自己寛容, 第16回 Kyoto T Cell Conference, Jun. 2006.
113.
Hirotsugu Kurobe, T Tominaga, A Kurushima, Masashi Kano, Takashi Kitaichi, Yutaka Masuda, Yousuke Takahama and Tetsuya Kitagawa : How will thymus extirpation in early infancy influence on achieving mature immune system?, The 14th Annual Meeting of the Asian Society for Cardiovascular Surgery, Jun. 2006.
Hirotsugu Kurobe, Tomoo Ueno, 斉藤 ふみ, 劉 村蘭, Tetsuya Kitagawa and Yousuke Takahama : Positively selected T lymphocytes can emigrate the thymus directly from the cortex, 第34回日本免疫学会総会, Dec. 2004.
Positive selection of T cells in the thymic cortex (Project/Area Number: 16H02630 )
Positive selection dictates T cell-mediated body defense (Project/Area Number: 26460576 )
Development and function of thymic microenvironments (Project/Area Number: 24111004 )
Analysis and Synthesis of Multidimensional Immune Organ Network (Project/Area Number: 24111001 )
The challenge for the development of therapy for autoimmune disorder by the establishment of artificial thymic medullary organ (Project/Area Number: 23659241 )
Molecular basis for the thymic microenvironments that characterize the immune system (Project/Area Number: 23249025 )
Roles of lymph node stromal cell network in T cell homeostasis (Project/Area Number: 22790467 )