Lipocalin 2 inhibits the expressions of interleukin-8 and macrophage inflammatory protein-1α in human neutrophil-like cells

Lipocalin 2 (LCN2) is a glycoprotein with multiple functions, including antimicrobial activity, inflammatory response modulation, and cell migration. LCN2 is expressed in some cells, such as epithelial cells and neutrophils, and its levels are increased in inflammatory diseases. This study investigated the presence of LCN2 receptor (24p3R) in cells around periodontal tissues and function of LCN2 in cells with a receptor to explore the role of LCN2 in periodontal diseases. The presence of 24p3R was examined in periodontal cells, including human gingival fibroblasts, periodontal ligament fibroblasts, human oral epithelial cells (HOECs), and neutrophil-like cells (HL-60), by Western blotting. Changes in periodontal disease-associated proteins in the presence of recombinant LCN2 (rLCN2) were examined using a protein array in differentiated HL-60 (dHL-60) cells. Interleukin-8 (IL-8) and macrophage inflammatory protein-1α (MIP-1α) mRNA expressions were analyzed by qRT-PCR, and IL-8 and MIP-1α levels in dHL-60 cells treated with rLCN2 or Porphyromonas gingivalis-lipopolysaccaharide (P.g-LPS) were determined by enzyme-linked immunosorbent assay. We detected 24p3R in dHL-60 cells. IL-8 was highly expressed and MIP-1α was weakly expressed in dHL-60 cells using a protein array. rLCN2 significantly decreased IL-8 mRNA and protein levels and suppressed P.g-LPS-induced IL-8 production in dHL-60 cells. As dHL-60 cells were co-cultured with HOECs in which LCN2 was knocked down, IL-8 mRNA expression increased in dHL-60 cells. Furthermore, rLCN2 inhibited MIP-1α production in dHL-60 cells. LCN2 suppresses inflammatory responses by regulating IL-8 and MIP-1α expression in periodontal diseases.


Lipocalin 2, synthesized using a cell-free protein synthesis system and encapsulated into liposomes, inhibits the adhesion of Porphyromonas gingivalis to human oral epithelial cells.


Porphyromonas gingivalis Outer Membrane Vesicles Stimulate Gingival Epithelial Cells to Induce Pro-Inflammatory Cytokines via the MAPK and STING Pathways

() is a keystone pathogen associated with chronic periodontitis and produces outer membrane vesicles (OMVs) that contain lipopolysaccharide (LPS), gingipains, and pathogen-derived DNA and RNA. -OMVs are involved in the pathogenesis of periodontitis. -OMV-activated pathways that induce the production of the pro-inflammatory cytokines, interleukin (IL)-6, and IL-8 in the human gingival epithelial cell line, OBA-9, were investigated. The role of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in levels of -OMV-induced pro-inflammatory cytokines was investigated using Western blot analysis and specific pathway inhibitors. -OMVs induced IL-6 and IL-8 production via the extracellular signal-regulated kinase (Erk) 1/2, c-Jun N-terminal kinase (JNK), p38 MAPK, and NF-κB signaling pathways in OBA-9 cells. In addition, the stimulator of interferon genes (STING), an essential innate immune signaling molecule, was triggered by a cytosolic pathogen DNA. -OMV-induced IL-6 and IL-8 mRNA expression and production were significantly suppressed by STING-specific small interfering RNA. Taken together, these results demonstrated that -OMV-activated Erk1/2, JNK, p38 MAPK, STING, and NF-κB signaling pathways resulting in increased IL-6 and IL-8 expression in human gingival epithelial cells. These results suggest that -OMVs may play important roles in periodontitis exacerbation by stimulating various pathways.


Gan-Lu-Yin (Kanroin), traditional Chinese herbal extracts, reduces osteoclast differentiation in vitro and prevents alveolar bone resorption in rat experimental periodontitis

Gan-Lu-Yin (GLY), a traditional Chinese herbal medicine, shows therapeutic effects on periodontitis, but that mechanism is not well known. This study aims to clarify the precise mechanism by investigating the inhibitory effects of GLY extracts on osteoclastogenesis in vitro and on bone resorption in periodontitis in vivo. RAW264.7 cells are cultured with soluble receptor activator of nuclear factor-kappa B (sRANKL) and GLY extracts (0.01-1.0 mg/mL), and stained for tartrate-resistant acid phosphatase (TRAP) to evaluate osteoclast differentiation. Experimental periodontitis is induced by placing a nylon ligature around the second maxillary molar in rats, and rats are administered GLY extracts (60 mg/kg) daily for 20 days. Their maxillae are collected on day 4 and 20, and the levels of alveolar bone resorption and osteoclast differentiation are estimated using micro-computed tomography (CT) and histological analysis, respectively. In RAW264.7 cells, GLY extracts significantly inhibit sRANKL-induced osteoclast differentiation at a concentration of more than 0.05 mg/mL. In experimental periodontitis, administering GLY extracts significantly decreases the number of TRAP-positive osteoclasts in the alveolar bone on day 4, and significantly inhibits the ligature-induced bone resorption on day 20. These results show that GLY extracts suppress bone resorption by inhibiting osteoclast differentiation in experimental periodontitis, suggesting that GLY extracts are potentially useful for oral care in periodontitis.


A low level of lysophosphatidic acid in human gingival crevicular fluid from patients with periodontitis due to high soluble lysophospholipase activity: Its potential protective role on alveolar bone loss by periodontitis.

We previously detected a submicromolar concentration of lysophosphatidic acid (LPA) in human saliva. Here, we compare LPA concentrations in human gingival crevicular fluid (GCF) from patients with periodontitis and healthy controls, and examine how the local LPA levels are regulated enzymatically. The concentrations of LPA and its precursor lysophospholipids in GCF was measured by liquid chromatography-tandem mass spectrometry. The LPA-producing and LPA-degrading enzymatic activities were measured by quantifying the liberated choline and free fatty acid, respectively. The concentration of LPA in GCF of periodontitis patients was lower than that of healthy controls, due to higher soluble lysophospholipase activity toward LPA. LPA was found to prevent survival of Sa3, a human gingival epithelium-derived tumor cell line, activate Sa3 through Ca mobilization, and release interleukin 6 from Sa3 in vitro. Furthermore, local injection of LPA into the gingiva attenuated ligature-induced experimental alveolar bone loss induced by oral bacteria inoculation in a rat model of periodontitis in vivo. A high concentration of LPA in human GCF is necessary to maintain normal gingival epithelial integrity and function, protecting the progression of periodontitis.

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids


Advanced glycation end-products increase lipocalin 2 expression in human oral epithelial cells.


S100A9 Increases IL-6 and RANKL Expressions through MAPKs and STAT3 Signaling Pathways in Osteocyte-Like Cells.


6-Shogaol inhibits advanced glycation end-products-induced IL-6 and ICAM-1 expression by regulating oxidative responses in human gingival fibroblasts

Advanced glycation end-products (AGEs) cause diabetes mellitus (DM) complications and accumulate more highly in periodontal tissues of patients with periodontitis and DM. AGEs aggravate periodontitis with DM by increasing the expression of inflammation-related factors in periodontal tissues. 6-Shogaol, a major compound in ginger, has anti-inflammatory and anti-oxidative activities. However, the influence of shogaol on DM-associated periodontitis is not well known. In this study, the effects of 6-shogaol on AGEs-induced oxidative and anti-oxidative responses, and IL-6 and ICAM-1 expression in human gingival fibroblasts (HGFs) were investigated. When HGFs were cultured with 6-shogaol and AGEs, the activities of reactive oxygen species (ROS) and antioxidant enzymes (heme oxygenase-1 [HO-1] and NAD(P)H quinone dehydrogenase 1 [NQO1]), and IL-6 and ICAM-1 expressions were investigated. RAGE expression and phosphorylation of MAPKs and NF-κB were examined by western blotting. 6-Shogaol significantly inhibited AGEs-induced ROS activity, and increased HO-1 and NQO1 levels compared with the AGEs-treated cells. The AGEs-stimulated expression levels of receptor of AGE (RAGE), IL-6 and ICAM-1 and the phosphorylation of p38, ERK and p65 were attenuated by 6-shogaol. These results suggested that 6-shogaol inhibits AGEs-induced inflammatory responses by regulating oxidative and anti-oxidative activities and may have protective effects on periodontitis with DM.


Advanced glycation end-product 2 and Porphyromonas gingivalis lipopolysaccharide increase sclerostin expression in mouse osteocyte-like cells

Sclerostin is a secreted glycoprotein that is mainly expressed in osteocytes, exerts negative effects on bone formation, and is present at elevated levels in diabetes mellitus (DM). Periodontitis is an infectious disease caused by periodontopathic bacteria, a complication of DM, and sometimes associated with severe inflammation and alveolar bone resorption. Advanced glycation end-products (AGEs) are a major pathogen in DM complications and adversely influence periodontitis in DM patients. In the present study, the effects of AGE2 and Porphyromonas gingivalis lipopolysaccharide (P-LPS) on the expression of sclerostin in mouse osteocyte-like cells (MLO-Y4-A2 cells) and its function in osteoblast differentiation were investigated. AGE2 and P-LPS up-regulated the expressions of receptor of AGE (RAGE) and Toll-like receptor 2 (TLR2), respectively, and significantly up-regulated that of sclerostin and interleukin 6 (IL-6) in osteocytes. Sclerostin, RAGE and TLR2 levels were synergistically increased by AGE2 and P-LPS. The siRNAs of RAGE and TLR2 significantly inhibited AGE2- and P-LPS-induced sclerostin expression. AGE2 up-regulated sclerostin expression in osteocyte-like cells via the RAGE, ERK and JNK, and NF-κB signal pathways. On the other hand, P-LPS elevated sclerostin levels via the TLR2, JNK and p38, and NF-κB signal pathways. When osteocytes pre-treated with AGE2 and P-LPS and osteoblastic cells (MC3T3-E1) were co-cultured in the medium with a sclerostin-neutralizing antibody, AGE2- and P-LPS-induced decreases in alkaline phosphatase activity and Runx2 expression in osteoblastic cells were significantly inhibited by the sclerostin-neutralizing antibody. These results suggest that AGE2 and P-LPS influence bone metabolism and inflammation through the regulation of sclerostin expression, and may aggravate periodontitis with DM.


Advanced glycation end-products increase IL-6 and ICAM-1 expression via RAGE, MAPK and NF-kB pathways in human gingival fibroblasts

Diabetes mellitus (DM) is a risk factor for periodontal diseases and may exacerbate the progression of the pathogenesis of periodontitis. Advanced glycation end-products (AGEs) cause DM complications relative to levels of glycemic control and larger amounts accumulate in the periodontal tissues of patients with periodontitis and DM. In the present study, we investigated the effects of AGEs on the expression of inflammation-related factors in human gingival fibroblasts (HGFs) to elucidate the impact of AGEs on DM-associated periodontitis. HGFs were cultured with or without AGEs. Cell viability was examined, and RNA and protein fractions were isolated from AGE-treated cells. The expression of interleukin (IL)-6, intercellular adhesion molecule-1 (ICAM-1), and the receptor for AGE (RAGE) was investigated using reverse transcription-polymerase chain reaction, quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and reactive oxygen species activity was measured using a kit with 2',7'-dichlorofluorescin diacetate. Human monocytic cells (THP-1) labeled with a fluorescent reagent were co-cultured with HGFs treated with AGEs and IL-6 siRNA, and the adhesive activity of THP-1 cells to HGFs was assessed. The expression of IL-6 and ICAM-1 was examined when HGFs were pretreated with recombinant human IL-6, the siRNAs of RAGE and IL-6, and inhibitors of MAPK and NF-κB, and then cultured with and without AGEs. The phosphorylation of MAPK and NF-κB was assessed using western blotting. AGEs increased the mRNA and protein expressions of RAGE, IL-6, ICAM-1 and reactive oxygen species activity in HGFs, and promoted the adhesion of THP-1 cells to HGFs, but had no effect on cell viability until 72 hours. Recombinant human IL-6 increased ICAM-1 expression in HGFs, while the siRNAs of RAGE and IL-6 inhibited AGE-induced IL6 and ICAM1 mRNA expression, and IL-6 siRNA depressed AGE-induced THP-1 cell adhesion. AGEs increased the phosphorylation of p38 and ERK MAPKs, p65 NF-κB and IκBα, while inhibitors of p38, ERK MAPKs and NF-κB significantly decreased AGE-induced IL-6 and ICAM-1 expression. AGEs increase IL-6 and ICAM-1 expression via the RAGE, MAPK and NF-κB pathways in HGFs and may exacerbate the progression of the pathogenesis of periodontal diseases.


Inhibitory effects of advanced glycation end-products and Porphyromonas gingivalis lipopolysaccharide on the expression of osteoblastic markers of rat bone marrow cells in culture

Diabetes is a major risk factor for periodontitis and there is a close relationship between the degree of hyperglycemia and the severity of periodontitis. Advanced glycation end-products (AGEs) accumulate in various tissues under diabetic conditions. AGEs in the periodontal tissues probably play a role in upregulating periodontal inflammation; however, the association of AGEs with the severity of periodontitis has not been fully clarified. Lipopolysaccharide from Porphyromonas gingivalis (P-LPS) is a potent pathogenic factor in periodontitis. Although the independent effect of AGE or P-LPS on osteoblastic cells has been reported in vitro, the effect of adding both has not been clearly elucidated. In this study, to explore factors aggravating diabetic periodontitis, we investigated the effects of AGE and P-LPS on the expression of osteoblastic markers and the expression of inflammation-related markers in vitro. Rat bone marrow cells were cultured, and alkaline phosphatase activity and bone nodule formation were evaluated as osteoblastic markers. Reverse transcription-polymerase chain reaction was performed to determine the mRNA expression of molecules associated with bone and inflammation. Protein levels of osteocalcin and interleukin-1β (IL-1β) were measured using enzyme-linked immunosorbent assay. AGEs and P-LPS independently reduced alkaline phosphatase activity and bone nodule formation. The addition of both AGE and P-LPS (AGE+P-LPS) further decreased these markers. Reverse transcription-polymerase chain reaction analysis revealed that AGE+P-LPS markedly decreased the mRNA expression of osteoblast-related molecules such as type 1 collagen, osteocalcin and Cbfa1, and markedly increased that of inflammation-related molecules such as IL1β and S100A8. AGE and P-LPS decreased the protein level of osteocalcin and increased that of IL-1β, and a further increase of IL-1β was detected for AGE+P-LPS. AGEs and P-LPS inhibited the expression of osteoblastic markers and increased the levels of inflammatory markers in rat bone marrow cells, suggesting that both AGE and P-LPS may be important factors associated with the aggravation of diabetic periodontitis.


Effect of Hangeshashinto on calprotectin expression in human oral epithelial cells.

Oral epithelial cells produce antimicrobial peptides (AMPs) to prevent microbial infection. Calprotectin (S100A8/S100A9) is one of these AMPs in oral epithelial cells, the expression of which is up-regulated by interleukin-1α (IL-1α). Hangeshashinto (HST) is a traditional Japanese herbal medicine that has anti-inflammatory effects. The purpose of this study was to investigate the effect of HST on the expression of calprotectin through the regulation of IL-1α in oral epithelial cells. Human oral epithelial cells (TR146) were cultured with HST in the presence or absence of anti-IL-1α antibody or IL-1 receptor antagonist, or with six major components of HST (3,4-dihydroxybenzaldehyde, baicalin, ginsenoside Rb1, glycyrrhizin, oleanolic acid and berberine). The expression of S100A8, S100A9, other AMPs and cytokine mRNAs was examined by RT-PCR and quantitative real-time PCR. Calprotectin expression and IL-1α secretion were investigated by ELISA. HST (6 μg/ml) increased the expression of S100A8/S100A9 mRNAs and calprotectin protein, and also up-regulated β-defensin 2 (DEFB4) and S100A7 expression. The expression of IL-1α mRNA and its protein was slightly but significantly increased by HST. A neutralizing antibody against IL-1α and IL-1 receptor antagonist inhibited HST-up-regulated S100A8/S100A9 mRNA expression. Although 3,4-dihydroxybenzaldehyde, baicalin and ginsenoside Rb1 as HST components increased S100A8/S100A9 expression, oleanolic acid and berberine decreased their expression. These results suggest that HST increases the expression of calprotectin, DEFB4 and S100A7 in oral epithelial cells. In response to HST, up-regulation of calprotectin expression may be partially induced via IL-1α.


Measles virus nucleocapsid protein increases osteoblast differentiation in Paget's disease.

Paget's disease (PD) is characterized by focal and dramatic bone resorption and formation. Treatments that target osteoclasts (OCLs) block both pagetic bone resorption and formation; therefore, PD offers key insights into mechanisms that couple bone resorption and formation. Here, we evaluated OCLs from 3 patients with PD and determined that measles virus nucleocapsid protein (MVNP) was expressed in 70% of these OCLs. Moreover, transgenic mice with OCL-specific expression of MVNP (MVNP mice) developed PD-like bone lesions that required MVNP-dependent induction of high IL-6 expression levels in OCLs. In contrast, mice harboring a knockin of p62P394L (p62-KI mice), which is the most frequent PD-associated mutation, exhibited increased bone resorption, but not formation. Evaluation of OCLs from MVNP, p62-KI, and WT mice revealed increased IGF1 expression in MVNP-expressing OCLs that resulted from the high IL-6 expression levels in these cells. IL-6, in turn, increased the expression of coupling factors, specifically ephrinB2 on OCLs and EphB4 on osteoblasts (OBs). IGF1 enhanced ephrinB2 expression on OCLs and OB differentiation. Importantly, ephrinB2 and IGF1 levels were increased in MVNP-expressing OCLs from patients with PD and MVNP-transduced human OCLs compared with levels detected in controls. Further, anti-IGF1 or anti-IGF1R blocked Runx2 and osteocalcin upregulation in OBs cocultured with MVNP-expressing OCLs. These results suggest that in PD, MVNP upregulates IL-6 and IGF1 in OCLs to increase ephrinB2-EphB4 coupling and bone formation.


PKR regulates LPS-induced osteoclast formation and bone destruction in vitro and in vivo.

PKR plays a pivotal role in LPS-induced bone loss in PD, and, thus, has potential as a therapeutic target for PD. This article is protected by copyright. All rights reserved.


YKL-40 level in gingival crevicular fluid from patients with periodontitis and type 2 diabetes

YKL-40 is a chitin-binding glycoprotein, the level of which increases in inflammatory diseases, diabetes mellitus (DM), cardiovascular diseases, and tumors. Gingival crevicular fluid (GCF) contains many proteins and markers of periodontitis. The purpose of this study was to investigate YKL-40 level in GCF from patients with periodontitis and DM and the association between YKL-40 level and chronic periodontitis (CP) or DM. The subjects were 121 patients with DM, CP, DM and periodontitis (DM-P), and healthy subjects (H). GCF was collected using paper strips after the sites for GCF collection were clinically evaluated for probing depth (PD), gingival index (GI), and bleeding on probing (BOP). YKL-40 in GCF was identified by Western blotting, and its level was determined by ELISA. YKL-40 was contained in GCF samples from H, DM, CP, and DM-P sites, and its levels (amount and concentration) in CP and DM-P were significantly higher than those in H and DM. GCF YKL-40 level significantly correlated with PD and GI, and its level in BOP-positive sites was significantly higher than that in BOP-negative ones. GCF YKL-40 level was elevated in periodontitis, but not DM. YKL-40 in GCF may be an inflammatory marker for periodontitis.


Gene polymorphism of β-defensin-1 is associated with susceptibility to periodontitis in Japanese.

Periodontitis is a multifactorial disease associated with genetic and environmental factors. Single-nucleotide polymorphisms (SNPs) are associated with susceptibility to common diseases such as diabetes and periodontitis. Although the oral cavity is exposed to various organisms, the conditions are well controlled by innate and acquired immune systems. Antimicrobial peptides (AMPs) play an important role in the innate immune system; however, the association of AMP-SNPs with periodontitis has not been fully elucidated. This study investigated the relationship between AMP-SNPs and periodontitis in Japanese. One hundred and five Japanese subjects were recruited, which included patients with aggressive, severe, moderate and mild periodontitis, and age-matched healthy controls. Genomic DNA was isolated from peripheral blood and genotypes of SNPs of β-defensin-1 and lactoferrin genes (DEFB1: rs1799946, rs1800972 and rs11362; and LTF: rs1126478) were investigated using the PCR-Invader assay. Protein level of AMPs in gingival crevicular fluid (GCF) was quantified by ELISA. Case-control studies revealed that the -44 CC genotype of DEFB1 (rs1800972) was associated with periodontitis (OR 2.51), particularly with severe chronic periodontitis (OR 4.15) and with combined severe and moderate chronic periodontitis (OR 4.04). No statistical differences were found in other genotypes. The β-defensin-1 concentrations in GCF were significantly lower in subjects with the -44 CC genotype of DEFB1 than in those without this genotype. No significant differences between GCF concentrations of AMPs and other genotypes were detected. The -44 CC genotype of the β-defensin-1 gene (DEFB1 rs1800972) may be associated with susceptibility to chronic periodontitis in Japanese.


肥満糖尿病ラット歯周炎の歯肉組織におけるオステオポンチンの局在

肥満糖尿病ラット歯周炎の歯肉組織におけるオステオポンチンの局在

Journal of the Japanese Association of Periodontology


Advanced glycation end-products increase expression of S100A8 and A9 via RAGE-MAPK in rat dental pulp cells

Advanced glycation end products (AGE) are involved in the progression of diabetic complications. Although our previous reports show that AGE increased dental pulp calcification, AGE accumulation is also associated with inflammation. This study examined AGE effect on the expression of inflammation factors using rat dental pulp tissues and cell cultures. Receptor for AGE (RAGE), S100A8, S100A9, and interleukin (IL)-1β were selected as inflammation parameters. Rat dental pulp cells were cultured and treated with AGE, and the effects were determined by real-time PCR. An anti-RAGE antibody or MAPK pathway inhibitors (PD98059, SB203580, and SP60012) were used to investigate AGE signaling pathway. The mRNA levels of RAGE, S100A8, S100A9, and IL-1β were higher in diabetic pulp tissues. AGE increased mRNA expressions of S100A8, S100A9, and IL-1β in cultured dental pulp cells. In the presence of anti-RAGE antibody, AGE did not increase in S100A8 or S100A9 expressions. The AGE-induced increases in S100A8 and S100A9 were inhibited by PD98059 and SB203580, respectively. Advanced glycation end products increased mRNA expression of S100A8, S100A9, and IL-1β under diabetic pulp conditions, and AGE-induced increases in S100A8 and S100A9 expressions may be associated with the RAGE-MAPK signaling pathway.


Glycated albumin and calprotectin levels in gingival crevicular fluid from patients with periodontitis and type 2 diabetes

Patients with diabetes mellitus (DM) have a high prevalence of periodontitis. Periodontitis in these patients is characterized by severe inflammation and tissue breakdown, and its diagnosis is important for cures of periodontitis and DM. The purpose of this study is to investigate the levels of glycated albumin (GA), a DM marker, and calprotectin, an inflammatory marker, in gingival crevicular fluid (GCF) from patients with periodontitis and DM (DM-P). The 78 participants in this study were patients with DM, chronic periodontitis (CP), DM-P, and healthy individuals (H). GCF and blood were collected, and GA and calprotectin in GCF were analyzed using Western blotting and enzyme-linked immunosorbent assay. Levels were compared among H, DM, CP, and DM-P groups. Blood GA and glycated hemoglobin (HbA1c) were measured, and the correlation among GCF GA and blood HbA1c or GA levels was investigated. Receiver operating characteristic (ROC) analysis for GCF GA to predict DM was performed. GA was identified in GCF, and its amount/concentration in GCF samples from DM and DM-P were significantly higher than those of non-DM groups (H and CP). Calprotectin amounts in GCF from CP and DM-P were significantly higher than in H and DM groups. GCF GA level was positively correlated with blood HbA1c and GA level. ROC analysis of GCF GA showed an optimal cutoff value to predict DM. GA showed a high level in GCF from patients with DM. Examination of GA and calprotectin in GCF may be useful for predicting DM-P.


Resveratrol improves oxidative stress and prevents the progression of periodontitis via the activation of the Sirt1/AMPK and the Nrf2/antioxidant defense pathways in a rat periodontitis model.

Oxidative stress is a key factor regulating the systemic pathophysiological effects associated with periodontitis. Resveratrol is a phytochemical with antioxidant and anti-inflammatory properties that can reduce oxidative stress and inflammation. We hypothesized that resveratrol may prevent the progression of periodontitis and reduce systemic oxidative stress through the activation of the Sirtuin1 (Sirt1)/AMP-activated protein kinase (AMPK) and the nuclear factor-E2 related factor 2 (Nrf2)/antioxidant defense pathways. Three groups of male Wistar rats (periodontitis treated with melinjo resveratrol, periodontitis without resveratrol, and control rats with no periodontitis or resveratrol treatment) were examined. A ligature was placed around the maxillary molars for 3 weeks to induce periodontitis, and the rats were then given drinking water with or without melinjo resveratrol. In rats with periodontitis, ligature placement induced alveolar bone resorption, quantified using three-dimensional images taken by micro-CT, and increased proinflammatory cytokine levels in gingival tissue. Melinjo resveratrol intake relieved alveolar bone resorption and activated the Sirt1/AMPK and the Nrf2/antioxidant defense pathways in inflamed gingival tissues. Further, melinjo resveratrol improved the systemic levels of 8-hydroxydeoxyguanosine, dityrosine, nitric oxide metabolism, nitrotyrosine, and proinflammatory cytokines. We concluded that oral administration of melinjo resveratrol may prevent the progression of ligature-induced periodontitis and improve systemic oxidative and nitrosative stress.


Advanced glycation end-products enhance calcification in cultured rat dental pulp cells

Amorphous calcification frequently appears in dental pulp tissues of diabetic patients; however, its pathologic process has not been fully elucidated. We previously found that pulp stones and thickened predentin occurred more frequently in diabetic rats. Recent findings demonstrated that accumulation of advanced glycation end-products (AGE) might be involved in vascular calcification complicated with diabetes. The aim of this study was to determine the effect of AGE on calcified nodule formation by rat dental pulp cells in culture. Rat dental pulp cells and gingival fibroblasts were independently cultured with 50 and 100 μg/mL AGE. Alkaline phosphatase activity and calcified nodule formation were measured. Expressions of receptor for AGE, osteopontin (OPN), and osteocalcin (OCN) mRNA were determined by quantitative real-time polymerase chain reaction. Protein levels of OPN and OCN secreted in culture medium were quantified by enzyme-linked immunosorbent assay. AGE (50 and 100 μg/mL) markedly increased both alkaline phosphatase activity and calcified nodule formation in dental pulp cells (P < .01), whereas it did not affect those in gingival fibroblasts. Real-time polymerase chain reaction analysis revealed that AGE increased mRNA expressions of receptor for AGE, OPN, and OCN in dental pulp cells (P < .05). Enzyme-linked immunosorbent assay analysis revealed that the protein levels of OPN and OCN produced by dental pulp cells were higher in AGE-treated than in untreated cells (P < .05). AGE enhanced the calcification potentials of rat dental pulp cells, suggesting that it may stimulate pathologic calcification of diabetic dental pulp tissues.


Association of gingival recession and other factors with the presence of dentin hypersensitivity.

Dentin hypersensitivity (DH) may be present in association with gingival recession. The aim of this study was to determine quantitatively the association of gingival recession and other factors with the presence of DH. One hundred and four Japanese subjects with or without gingival recession were randomly selected. Intact canines and/or first premolars in both maxillary and mandibular quadrants were analyzed. Gingival recession was measured as a vertical length at the buccal site of the teeth. DH was recorded as an ordered categorical variable registering four increasing levels of pain after cold stimulation; from no discomfort to severe pain during and after stimulation (DH1, 2, 3, and 4). Association of DH with periodontal parameters and daily lifestyle was also investigated. Tooth-based analysis of 446 teeth from 104 subjects revealed that DH level was significantly higher in recessive teeth (1, 2, 3, and 4-8 mm) than in non-recessive teeth (0 mm). DH-positive rate in non-recessive teeth was only 18 % (DH1; 14 %, DH2; 3 %, and DH3; 1 %). Highest DH level was observed in teeth with severe recession (4-8 mm), showing DH0; 21 %, DH1; 33 %, DH2; 31 %, and DH3; 15 %. Recession-dependent increase in DH was observed, showing 18, 49, 52, 60, and 79 % DH-positive in teeth with 0, 1, 2, 3, and 4-8 mm recession, respectively. Plaque-free teeth showed a higher DH level than plaque-stained teeth, suggesting that good plaque control may be associated with the presence of DH. There were no significant differences in DH of teeth on the basis of smoking, probing depth, and bleeding on probing. Multiple logistic regression analysis revealed that gingival recession [odds ratio (OR) = 10.2, 95 % confidence interval (CI) = 5.5-18.9] and plaque deposition (OR = 0.3, 95 % CI = 0.2-0.5) were significant contributors to DH. Multilevel modeling analysis revealed that not only gingival recession and plaque deposition but also V-shaped cervical notch and tooth brushing frequency were associated with DH. These results demonstrate that the progression of gingival recession, plaque-free teeth, V-shaped cervical notch, and frequent brushing may be significant predictors of DH in canines and first premolars.


Resistin in gingival crevicular fluid and induction of resistin release by Porphyromonas gingivalis lipopolysaccharide in human neutrophils

Resistin is an adipocytokine that induces insulin resistance and is predominantly expressed in adipocytes and peripheral blood mononuclear cells. Resistin expression increases in inflammatory diseases as well as diabetes mellitus, and is upregulated by bacterial pathogens and proinflammatory cytokines. The aim of this study was to identify resistin in human gingival crevicular fluid, to compare the resistin levels in gingival crevicular fluid between subjects with and without periodontitis and diabetes mellitus and to investigate the regulation of resistin release from human neutrophils by Porphyromonas gingivalis lipopolysaccharide (P-LPS). Gingival crevicular fluid samples were collected from patients with chronic periodontitis (n = 24), patients with diabetes mellitus-related periodontitis (n = 18) and healthy subjects (n = 21). Resistin in gingival crevicular fluid was determined using western blot analysis and an ELISA kit. The glycated hemoglobin (HbA(1c)) value was obtained from patients with diabetes mellitus-related periodontitis by a medical interview. Human neutrophils were cultured with P-LPS (0-1000 ng/mL), or incubated with inhibitors of actin or microtubule polymerization in the absence or presence of P-LPS. The medium and cellular fractions were used for determination of resistin by ELISA. The resistin level in gingival crevicular fluid from patients with periodontitis or diabetes mellitus-related periodontitis was significantly higher than that of healthy subjects. The resistin level in gingival crevicular fluid was correlated with gingival index score, but not blood HbA(1c) value. The P-LPS increased resistin release from human neutrophils, and its induction was decreased by actin polymerization inhibitors. We show, for the first time, the presence of resistin in gingival crevicular fluid. A high resistin level in gingival crevicular fluid samples from periodontitis patients may to some extent be related to P-LPS-induced resistin release from neutrophils.


Regulation of antimicrobial peptide expression in human gingival keratinocytes by interleukin-1α

In the oral cavity, mucosal keratinocytes resist bacterial infection, in part, by producing broad-spectrum antimicrobial peptides (AMPs) including defensin, adrenomedullin and calprotectin. Epidermal keratinocyte expression of many AMPs increases in response to interleukin-1α (IL-1α). IL-1α is produced by epidermal keratinocytes and regulates cell differentiation. To better understand innate immunity in the oral cavity, we sought to determine how IL-1α might regulate expression of AMPs by human gingival keratinocytes (HGKs) using DNA microarray and Western blot analyses. HGKs from three subjects expressed eleven AMPs, including S100A7, S100A8, S100A9, S100A12, secretory leucocyte protease inhibitor, lipocalin 2 (LCN2), cystatin C and β-defensin 2. Of the expressed AMPs, S100A7, S100A12 and LCN2 were up-regulated by IL-1α (inducible AMPs); the other AMPs were considered to be constitutive. Human gingival keratinocytes, therefore, express constitutive and IL-1α-inducible AMPs to provide a rapid and robust innate response to microbial infection.


Osmotic Stress Affects Calcium Deposition and Osteopontin Expression in Cultured Rat Dental Pulp Cells

オスモティックストレスが培養歯髄細胞の硬組織形成能とオステオポンチン産生に及ぼす影響

Osmotic stress is a stimulus caused by osmotic pressure, which is known to affect physiological functions in various tissues and cells. However, there is little information on the effect of osmotic stress on dental pulp tissues and cells. In this study, we investigated the relationship between osmotic stress and calcium deposition in cultured rat dental pulp cells. We also analyzed the effect of osmotic stress on the expression and phosphorylation of osteopontin (OPN), a multi-functional bone matrix protein, in the dental pulp cells. Both hypo- and hyper-osmotic stress affected cell-shape and -growth, and decreased calcium deposition in cultured rat dental pulp cells. Hypoosmotic stress increased OPN secretion and its protein ratio in the culture medium. Also, the secreted OPN was highly phosphorylated. On the other hand, hyper-osmotic stress decreased OPN secretion and its protein ratio and most of the OPN in the hypertoinc medium was dephosphorylated. Both hypo- and hyper-osmotic stress decreased calcium deposition in the cultured rat dental pulp cells. However, the mechanism of the inhibitory action seemed to be different in the two groups, because the amount and phosphorylation pattern of OPN were not similar between the hypo- and hyper-osmotic conditions. We concluded that osmotic stress affects calcium deposition in cultured rat dental pulp cells and that OPN expression and its phosphorylation may be a control factor of osmotic stress-associated mineralization.

浸透圧変化が惹起する刺激源は一般にオスモティックストレス(osmotic stress)と呼ばれており,種々の組織や細胞に影響をもたらすことが知られている.しかし,オスモティックストレスが歯髄の組織や細胞にどのような影響を与えるのかを論じた成書や研究報告はぼとんどない.本研究ではラット由来の歯髄細胞培養系を用いて,オスモティックストレスと歯髄細胞の硬組織形成の関連性を検証した.また,オスモティックストレスによって硬組織形成関連タンパクであるオステオポンチン(OPN)の発現やリン酸化に変化が生じるかも検証した.その結果,歯髄細胞培養系においては,低張および高張のいずれのオスモティックストレスによっても細胞の形態や増殖に影響が認められ,硬組織形成も低下した.低張ストレスを付与するとOPNの発現量や総タンパク量に対するOPNの比率は上昇し,また発現したOPNはリン酸化されていた.一方,高張ストレスを付与するとOPNの発現量や総タンパク量に対するOPNの比率は低下し,脱リン酸化されたOPNが主に発現した.このように低張と高張のオスモティックストレスではOPNの発現量やリン酸化による修飾の程度が異なっていたことから,低張および高張のいずれのオスモティックストレスによっても石灰化は抑制されたが,その抑制のメカニズムは一様でないことが明らかとなった.以上より,オスモティックストレスは歯髄細胞の硬組織形成に影響を与え,OPNの発現およびそのリン酸化が制御因子として機能している可能性が示唆された.

The Japanese Journal of Conservative Dentistry


Shosaikoto increases calprotectin expression in human oral epithelial cells.

BACKGROUND AND OBJECTIVE: Oral epithelial cells help to prevent against bacterial infection in the oral cavity by producing antimicrobial peptides (AMPs). A broad-spectrum AMP, calprotectin (a complex of S100A8 and S100A9 proteins), is expressed by oral epithelial cells and is up-regulated by interleukin-1alpha (IL-1alpha). Shosaikoto (SST) is a traditional Japanese herbal medicine that has immunomodulatory effects and is reported to enhance the levels of IL-1alpha in epithelial cells. The purpose of this study was to investigate the effect of SST on the expression of calprotectin and other AMPs through the regulation of IL-1alpha in oral epithelial cells. MATERIAL AND METHODS: Human oral epithelial cells (TR146) were cultured with SST (at concentrations ranging from 10 to 250 microg/mL) in the presence or absence of anti-IL-1alpha or IL-1 receptor antagonist. The expression of S100A8- and S100A9-specific mRNAs was examined by northern blotting. Calprotectin expression and IL-1alpha secretion were investigated by immunofluorescent staining or ELISA. The expression of other AMPs and IL-1alpha was analyzed by RT-PCR and by quantitative real-time PCR. RESULTS: Shosaikoto (25 microg/mL) significantly increased the expression of S100A8- and S100A9-specific mRNAs and calprotectin protein. Shosaikoto increased S100A7 expression, but had no effect on the expression of other AMPs. The expression of IL-1alpha-specific mRNA and its protein were slightly increased by SST. A neutralizing antibody against IL-1alpha or IL-1 receptor antagonist inhibited SST up-regulated S100A8/S100A9 mRNA expression. CONCLUSION: These results suggest that SST increases the expression of calprotectin and S100A7 in oral epithelial cells. In response to SST, up-regulation of calprotectin may be partially induced via IL-1alpha.


High glucose levels increase osteopontin production and pathologic calcification in rat dental pulp tissues.

INTRODUCTION: Pulp stones are frequently formed as a pathologic calcification product in dental pulp tissues, but the pathogenesis is poorly understood. We previously found that osteopontin (OPN) was produced by dental pulp cells, and its expression was associated with formation of the pulp stone matrix. It was reported that amorphous calcification appeared in the dental pulp of diabetic patients. The aim of this study was to determine the relationship between OPN expression and pathologic calcification in rat diabetic pulp. METHODS: The effect of glucose on OPN production and alkaline phosphatase activity in cultured rat dental pulp cells (RPC-C2A) was investigated, and then dental pulp calcification and OPN expression in diabetic rats were determined and compared with those in healthy rats by histologic and immunohistochemical analyses. RESULTS: In RPC-C2A cells, biochemical analysis showed that a high concentration of glucose (50 mmol/L) increased OPN protein production and alkaline phosphatase activity 1.3-fold and 1.5-fold, respectively. Histologic observations showed more calcified particles in dental pulp tissues in diabetic than in nondiabetic rats. Moreover, a thickened layer of predentin was formed in the radicular pulp of diabetic rats. OPN was more strongly stained around the calcified particles and in the odontoblast zone under the thickened predentin in diabetic rats. CONCLUSIONS: OPN might be a key molecule involved in the increase of pathologic pulp calcifications, which are frequently observed in diabetic patients.


Long-term Observation of Marked Overfilling in Root Canal Therapy : A Report of Three Cases

著明な過剰根管充填の経過を長期観察した3症例

In endodontic therapy, overfilling of gutta-percha point in root canals sometimes occurs due to wrong measurement of working length and overextension of gutta-percha point. Although a slight overfilling to periapical tissues (within 2 mm past the apical foramen) is tolerable, marked overfilling should be checked by postoperative recheck radiographs and/or clinical symptoms. In this report, three clinical cases of marked overfilling are described and long-term radiographic observation (6-14 years) was continued. Overfilled gutta-percha points on the radiographic observation were 3.0 (case 1), 2.5 (case 2), and 3.5 mm (case 3) in the left maxillary molar of a 47-year-old woman, in the left mandibular molar of a 45-year-old woman, and in the left mandibular premolar of a 39-year-old woman, respectively. In case 1, an overfilled point was cut after 1.5 years and disappeared after 3.5 years, and then apical radiolucency was improved after 6 years. In case 2, overfilled points started to minimize after 3 years and disappeared after 14 years. In case 3, an overfilled point was minimized after 13 years accompanied with improvement of apical lesion. None of the cases showed any significant clinical symptoms after the overfilling. These observations are interesting to longitudinally evaluate the disappearance of overfilled gutta-percha and the improvement of apical lesion.

歯内治療において,ときどき過剰根管充填(過剰根充)に遭遇する.一般に,過剰根充は作業長の測定ミスや根充操作時のガッタパーチャポイントの根尖孔外への突き出しが主な原因であるといわれている.根尖孔から2mm以内のわずかな過剰根充であれば根尖歯周組織に為害性はないが,それ以上の著しい過剰根充の場合は,術後の症状やX線写真によるチェックを行い注意深く対応する必要がある.本報告では,X線写真上で2.5∼3.5mmのポイントの突出が認められた3症例(症例1:上顎第二大臼歯,3.0mm,症例2:下顎第一大臼歯,2.5mm,症例3:下顎第一小臼歯,3.5mm)について,最長6∼14年の経過観察を行った結果を提示した.症例1では,突出ポイントは1年5カ月後に切断され3年8カ月後に消失し,6年8カ月後に根尖透過像も改善した.症例2では,突出ポイントは3年後に縮小傾向を示し,14年7カ月後には消失しており,根尖透過像の消失,歯槽硬線の明瞭化が観察された.症例3では,突出ポイントは13年6カ月後にわずかな部分を残して,ほとんどが吸収しており,同時に根尖透過像も消失していた.臨床症状は,症例1で打診痛が長期残存したほかには特記事項はほとんど認められなかった.当該歯は現在も健常に機能している.今回の症例は,術前診断,術中術後の情報を詳細に提示しながら過剰根充されたガッタパーチャポイントの経過と根尖病巣の治癒経過を長期間追跡したものであり,過剰根充の転帰を知るうえで興味深い臨床報告である.


A new genetic assay for rifampicin susceptibility of Mycobacterium tuberculosis.


Chimeric HU-IHF proteins that alter DNA-binding ability.


Diagnosis of Periodontal Diseases using Biomarkers in Gingival Crevicular Fluid

歯肉溝滲出液中のバイオマーカーを用いた歯周病診断

Periodontal diseases cause an inflammation and degradation of periodontal tissues and missing of teeth. The incidence rate of periodontal diseases is high in middle-aged and elderly people.A reasonable diagnosis of periodontal diseases is very important to keep teeth, however, conventional examinations of periodontal diseases is not necessarily exact and objective. Gingival crevicular fluid (GCF) is an exudate secreted from periodontal tissues and contains many components including proteolytic enzymes, inflammatory cytokines, blood-associated proteins, cellular and bacterial fragments. Because some proteins in GCF are related to inflammation, tissue degradation and bone metabolism, those proteins have been studying as a diagnostic marker of periodontal diseases. GCF is noninvasively collected using a sterile paper strip and biomarkers are determined using enzyme-linked immunosorbent assay (ELISA) and enzyme activity assay. We identified calprotectin, an inflammationrelated protein, in GCF and calprotectin level in GCF from periodontitis sites was significantly higher than that of healthy control. Calprotectin level in GCF was positively correlated to gingival index and other biomarkers and decreased by periodontal treatments. Resistin is an adipocytokine and its level increases in some inflammatory diseases. Resistin level in GCF from periodontitis sites was high compared to the level of healthy control samples. Procollagen type I C-terminal peptide (PICP) is a biomarker for bone metabolism and its level was high in GCF collected from periodontitis sites. These results suggested that calprotectin, resistin and PICP are useful biomarkers for periodontal diseases. On the other hand, we showed that glycated albumin (GA), a marker of diabetes mellitus (DM), was contained in GCF and GA level in GCF from DM patients was significantly higher than that of non-DM individuals. Components in GCF may be biomarkers of systemic diseases as well as periodontal diseases and their determination will be useful diagnostic examination of some diseases. Recently, we have been studying the determining system of GCF calprotectin, including microchip ELISA, surface plasmon resonance assay and immuno-chromatography assay. When GCF biomarkers are determined using the determining systems, we will simply, exactly and objectively diagnose periodontal diseases at our dental offices.