Yumiko Miyatake, Yuna Mishima, Rie Tsutsumi, Tamaki Otani, Naoya Suemasa, Saeko Masumoto, Masashi Kuroda and Hiroshi Sakaue : Assessment of insulin resistance in the skeletal muscle of mice using positron emission tomography/computed tomography imaging., Biochemical and Biophysical Research Communications, Vol.528, No.3, 499-505, 2020.
(Summary)
F]-fluoro-2-deoxy-D-glucose (FDG). FDG-PET/CT imaging revealed that insulin administration and exercise load significantly increased FDG accumulation in the skeletal muscle of C57BL/6J mice. FDG accumulation was lower in the skeletal muscle of 14-week-old db/db diabetic model mice exhibiting remarkable insulin resistance compared to that of 7-week-old db/db mice. Based on the continuous observation of FDG accumulation over time in diet-induced obese (DIO) mice, FDG accumulation significantly decreased in 17-week-old mice after the acquisition of insulin resistance. Although insulin-induced glucose uptake in the skeletal muscle was markedly attenuated in 20-week-old DIO mice that had already developed insulin resistance, exercise load effectively increased FDG uptake in the skeletal muscle. Thus, we successfully confirmed that glucose uptake accompanied by insulin administration and exercise load increased in the skeletal muscle using PET-CT. FDG-PET/CT might be an effective tool that could noninvasively capture the chronological changes of metabolic abnormalities in the skeletal muscle of mice.
Nagakatsu Harada, Yuka Gotoda, Adzumi Hatakeyama, Tadahiko Nakagawa, Yumiko Miyatake, Masashi Kuroda, Saeko Masumoto, Rie Tsutsumi, Yutaka Nakaya and Hiroshi Sakaue : Differential regulation of Actn2 and Actn3 expression during unfolded protein response in C2C12 myotubes., Journal of Muscle Research and Cell Motility, 2020.
(Summary)
ACTN2 and ACTN3 encode sarcomeric α-actinin-2 and α-actinin-3 proteins, respectively, that constitute the Z-line in mammalian skeletal muscle fibers. In human ACTN3, a nonsense mutation at codon 577 that encodes arginine (R) produces the R577X polymorphism. Individuals having a homozygous 577XX genotype do not produce α-actinin-3 protein. The 577XX genotype reportedly occurs in sprint and power athletes in frequency lower than in the normal population, suggesting that α-actinin-3 deficiency diminishes fast-type muscle function. Among humans who carry 577R alleles, varying ACTN3 expression levels under certain conditions can have diverse effects on atheletic and muscle performance. However, the factors that regulate ACTN3 expression are unclear. Here we investigated whether the unfolded protein response (UPR) under endoplasmic reticulum (ER) stress regulates expression of Actn3 and its isoform Actn2 in mouse C2C12 myotubes. Among UPR-related transcription factors, XBP1 upregulated Actn2, whereas XBP1, ATF4 and ATF6 downregulated Actn3 promoter activity. Chemical induction of ER stress increased Actn2 mRNA levels, but decreased those for Actn3. ER stress also decreased α-actinin-3 protein levels, whereas levels of α-actinin-2 were unchanged. The intracellular composition of muscle contraction-related proteins was altered under ER stress, in that expression of parvalbumin (a fast-twitch muscle-specific protein) and troponin I type 1 (skeletal, slow) was suppressed. siRNA-induced suppression of Actn3 mimicked the inhibitory effect of ER stress on parvalbumin levels. Thus, endogenous expression levels of α-actinin-3 can be altered by ER stress, which may modulate muscle performance and athletic aptitudes, particularly in humans who carry ACTN3 577R alleles.
Hypertrophy, associated with adipocyte dysfunction, causes increased pro-inflammatory adipokine, and abnormal glucose and lipid metabolism, leading to insulin resistance and obesity-related-health problems. By combining DNA microarray and genomic data analyses to predict DNA binding motifs, we identified the transcription factor Interferon Regulatory Factor 7 (IRF7) as a possible regulator of genes related to adipocyte hypertrophy. To investigate the role of IRF7 in adipocytes, we examined gene expression patterns in 3T3-L1 cells infected with a retrovirus carrying the IRF7 gene and found that enforced IRF7 expression induced the expression of monocyte chemoattractant protein-1 (MCP-1), a key initial adipokine in the chronic inflammation of obesity. CRISPR/Cas9 mediated-suppression of IRF7 significantly reduced MCP-1 mRNA. Luciferase assays, chromatin immunoprecipitation PCR analysis and gel shift assay showed that IRF7 transactivates the MCP-1 gene by binding to its proximal Interferon Stimulation Response Element (ISRE), a putative IRF7 binding motif. IRF7 knockout mice exhibited lower expression of MCP-1 in epidydimal white adipose tissue under high-fat feeding conditions, suggesting the transcription factor is physiologically important for inducing MCP-1. Taken together, our results suggest that IRF7 transactivates MCP-1 mRNA in adipocytes, and it may be involved in the adipose tissue inflammation associated with obesity.
Tetsuya Hosooka, Yusei Hosokawa, Kaku Matsugi, Masakazu Shinohara, Yoko Senga, Yoshikazu Tamori, Chikako Aoki, Sho Matsui, Tsutomu Sasaki, Tadahiro Kitamura, Masashi Kuroda, Hiroshi Sakaue, Kazuhiro Nomura, Kei Yoshino, Yuko Nabatame, Yoshito Itoh, Kanji Yamaguchi, Yoshitake Hayashi, Jun Nakae, Domenico Accili, Takehiko Yokomizo, Susumu Seino, Masato Kasuga and Wataru Ogawa : The PDK1-FoxO1 signaling in adipocytes controls systemic insulin sensitivity through the 5-lipoxygenase-leukotriene B 4 axis, Proceedings of the National Academy of Sciences of the United States of America, Vol.117, No.21, 11674-11684, 2020.
(Summary)
Although adipocytes are major targets of insulin, the influence of impaired insulin action in adipocytes on metabolic homeostasis remains unclear. We here show that adipocyte-specific PDK1 (3'-phosphoinositide-dependent kinase 1)-deficient (A-PDK1KO) mice manifest impaired metabolic actions of insulin in adipose tissue and reduction of adipose tissue mass. A-PDK1KO mice developed insulin resistance, glucose intolerance, and hepatic steatosis, and this phenotype was suppressed by additional ablation of FoxO1 specifically in adipocytes (A-PDK1/FoxO1KO mice) without an effect on adipose tissue mass. Neither circulating levels of adiponectin and leptin nor inflammatory markers in adipose tissue differed between A-PDK1KO and A-PDK1/FoxO1KO mice. Lipidomics and microarray analyses revealed that leukotriene B4 (LTB4) levels in plasma and in adipose tissue as well as the expression of 5-lipoxygenase (5-LO) in adipose tissue were increased and restored in A-PDK1KO mice and A-PDK1/FoxO1KO mice, respectively. Genetic deletion of the LTB4 receptor BLT1 as well as pharmacological intervention to 5-LO or BLT1 ameliorated insulin resistance in A-PDK1KO mice. Furthermore, insulin was found to inhibit LTB4 production through down-regulation of 5-LO expression via the PDK1-FoxO1 pathway in isolated adipocytes. Our results indicate that insulin signaling in adipocytes negatively regulates the production of LTB4 via the PDK1-FoxO1 pathway and thereby maintains systemic insulin sensitivity.
Masashi Kuroda, Rumi Onoyama, Waka Sasaki, Mayu Sebe, Tadahiro Kitamura, Saeko Masumoto, Rie Tsutsumi, Nagakatsu Harada and Hiroshi Sakaue : DNA methylation status influences insulin-induced glucose transport in 3T3-L1 adipocytes by mediating p53 expression., Biochemical and Biophysical Research Communications, Vol.525, No.1, 39-45, 2020.
(Summary)
Researchers frequently use 3T3-L1 adipocytes as a fat cell line, but the capacity of this line for insulin-mediated glucose transport is lower than that of primary isolated fat cells. In this study, we found that 5-azacytidine (5-aza-C), DNA methyltransferase 1 inhibitor, enhanced insulin-stimulated 2-deoxyglucose (2-DG) transport in 3T3-L1 cells after adipogenic differentiation. We next examined the expression of the genes related to glucose transport and insulin signal transduction. The insulin independent glucose transporter, glucose transporter 1 (GLUT1), showed lower expression in 5-aza-C pre-treated 3T3-L1 adipocytes, than in un-treated control adipocytes, while the expression of insulin dependent transporter GLUT4 remained unchanged. In addition, insulin receptor substrate-1 (IRS-1) was highly expressed in 5-aza-C pre-treated adipocytes. Based on DNA microarray and functional annotation analysis, we noticed that 5-aza-C pretreatment activated the tumor suppressor p53 pathway. We confirmed that in 5-aza-C adipocytes, p53 expression was markedly higher, and the methylation level of CpGs in its promoter region was lower than in un-treated control adipocytes. Moreover, pharmacological inhibition of p53 restored GLUT1 and IRS-1 expression to the same level as in un-treated 3T3-L1 adipocytes, and significantly decreased insulin-mediated 2-DG uptake. These results suggest that glucose transport capacity in adipocytes is influenced by DNA methylation status, and demethylation induced by 5-aza-C increased it possibly through the p53 signaling pathway.
Mayu Sebe, Rie Tsutsumi, Takuro Oyama, T Yousuke Horikawa, Yuta Uemura, Nami Kakuta, Yoko Sakai, Atsushi Morio, Hirotsugu Miyoshi, Takashi Kondo, Tomoaki Urabe, Yuko Noda, Satoshi Kamiya, Noboru Saeki, Masashi Kuroda, Katsuya Tanaka, Yasuo Tsutsumi and Hiroshi Sakaue : Assessment of postoperative nutritional status and physical function between open surgical aortic valve replacement and transcatheter aortic valve implantation in elderly patients., The Journal of Medical Investigation : JMI, Vol.67, No.1.2, 139-144, 2020.
(Summary)
Background and aims : Severe aortic stenosis (AS) has been normally treated with surgical aortic valve replacement (AVR) whereas recently, transcatheter aortic valve implantation (TAVI) has been introduced as a minimally invasive operation for patients with high surgical risk and frailty. In this study, we have evaluated postoperative physical function and nutrition intake in the patients following AVR and TAVI. Methods : This prospective observational study involved 9 patients with surgical aortic valve replacement (AVR) and 7 patients with transcatheter aortic valve implantation (TAVI). Body composition was measured one day prior surgery, postoperative day (POD) 1, POD 3, POD 5 and POD 7. Hand grip strength, calf circumference and gait speed were measured one day before surgery and on the day of discharge. Results : Skeletal muscle was significantly decreased in AVR patients at postoperative day 3 and 7, while there was no change in TAVI patients. Patients with TAVI showed higher dietary intake after surgery compared to patients with AVR, and they maintained hand grip strength and calf circumference at discharge. Conclusions : In elderly patients with AS, TAVI can improve post-operative recovery maintaining nutritional status and physical function even. J. Med. Invest. 67 : 139-144, February, 2020.
Masahiro Bando, Saeko Masumoto, Masashi Kuroda, Rie Tsutsumi and Hiroshi Sakaue : Effect of olive oil consumption on aging in a senescence-accelerated mice-prone 8 (SAMP8) model., The Journal of Medical Investigation : JMI, Vol.66, No.3.4, 241-247, 2019.
(Summary)
Background : Mediterranean diets have been linked to a reduced risk of cancer, vascular illnesses, Parkinson's and Alzheimer's disease. Olive oil is the primary fat source in the Mediterranean diet ; however, only a few studies have investigated the effect of olive oil on aging. In the present study, we aimed to determine whether consumption of olive oil significantly influences aging and memory in senescence-accelerated mouse-prone 8 (SAMP8). Methods : SAMP8 and senescence-accelerated mouse resistant 1 (SAMR1) mice were fed either 7% soy oil or 1% olive oil and 6% soy oil during a six-month study period. Reduction in memory in passive avoidance learning was examined after two months from the initiation of the experiment. Results : The weight of organs including the liver, kidney, spleen, and fat tissue changed significantly and memory performance was reduced in SAMP8 than in SAMR1 mice. There were no significant differences in SAMP8 and SAMR1 mice; however, blood triglyceride level decreased significantly in SAMP8 mice fed on olive oil. Conclusions : These results suggest that consuming olive oil may not have a protective role in aging and memory recall, but beneficial effects may be related to improvement in lipid metabolism. J. Med. Invest. 66 : 241-247, August, 2019.
Rie Tsutsumi, 瀬部 真由, 別府 香名, 渡辺 涼乃, 尾平 優, Masashi Kuroda and Hiroshi Sakaue : Management of dysgeusia and dysosmia caused by chemotherapy, The Journal of Japanese Society for Parenteral and Enteral Nutrition, Vol.33, No.4, 1019-1024, 2018.
expression and thereby induced production of full-length α-actinin-3 protein in the presence of aminoglycoside. Together these results indicate that the ACTN3 R577X polymorphism could be a novel target for readthrough therapy, which may affect athletic and muscle performance in humans.
Chikugo Momoko, Sebe Mayu, Rie Tsutsumi, Iuchi Marina, Jun Kishi, Masashi Kuroda, Nagakatsu Harada, Yasuhiko Nishioka and Hiroshi Sakaue : Effect of Janus kinase inhibition by tofacitinib on body composition and glucose metabolism., The Journal of Medical Investigation : JMI, Vol.65, No.3.4, 166-170, 2018.
(Summary)
Tofacitinib is the first Janus Kinase (JAK) inhibitor to treat moderately to severely active RA. In this study, we investigated whether the effect of tofacitinib have any effects on body composition in mice and female patients with RA. Female C57BL/6 mice fed with a high-fat diet were treated with 30 mg/kg/day tofacitinib or vehicle for 70 days. Following treatment, trunk muscle, subcutaneous fat, and visceral fats were measured using X-ray computed tomography CT scan. Glucose tolerance and insulin sensitivity were assessed. In female RA patients treated with biological disease modified anti-rheumatic-drugs (biological DMARDs) or tofacitinib (n=4 per group), we also evaluated the body composition after 3 months from the start of treatment initiation using bioelectrical impedance analysis. Treatment with tofacitinib did not affect the body weight, and body composition in C57BL/6 mice. It also did not affect glucose, and insulin tolerance in mice. In patients with RA, treatment with biological DMARDs did not affect the body composition whereas the muscle mass was unchanged after receiving tofacitinib and the fat mass was significantly increased. J. Med. Invest. 65:166-170, August, 2018.
As a novel model of muscle wasting, HSA-Fv2E-PERK Tg mice provide a convenient tool for studying the pathogenesis of muscle loss and for assessing putative therapeutics.
There is an increasing interest in elucidating the molecular mechanisms by which voluntary exercise is regulated. In this study, we examined how the central nervous system regulates exercise. We used SPORTS rats, which were established in our laboratory as a highly voluntary murine exercise model. SPORTS rats showed lower levels of serum ghrelin compared with those of the parental line of Wistar rats. Intracerebroventricular and intraperitoneal injection of ghrelin decreased wheel-running activity in SPORTS rats. In addition, daily injection of the ghrelin inhibitor JMV3002 into the lateral ventricles of Wistar rats increased wheel-running activity. Co-administration of obestatin inhibited ghrelin-induced increases in food intake but did not inhibit ghrelin-induced suppression of voluntary exercise in rats. Growth hormone secretagogue receptor (GHSR) in the hypothalamus and hippocampus of SPORTS rats was not difference that in control rats. We created an arcuate nucleus destruction model by administering monosodium glutamate (MSG) to neonatal SPORTS rats. Injection of ghrelin into MSG-treated rats decreased voluntary exercise but did not increase food intake, suggesting that wheel-running activity is not controlled by the arcuate nucleus neurons that regulate feeding. These results provide new insights into the mechanism by which ghrelin regulates voluntary activity independent of arcuate nucleus neurons.
Masashi Kuroda, Ayako Tominaga, Kasumi Nakagawa, Misa Nishiguchi, Mayu Sebe, Yumiko Miyatake, Tadahiro Kitamura, Rie Tsutsumi, Nagakatsu Harada, Yutaka Nakaya and Hiroshi Sakaue : DNA Methylation Suppresses Leptin Gene in 3T3-L1 Adipocytes., PLoS ONE, Vol.11, No.8, e0160532, 2016.
(Summary)
Leptin is a key regulator of energy intake and expenditure. This peptide hormone is expressed in mouse white adipose tissue, but hardly expressed in 3T3-L1 adipocytes. Using bisulfite sequencing, we found that CpG islands in the leptin promoter are highly methylated in 3T3-L1cells. 5-azacytidine, an inhibitor of DNA methyltransferase, markedly increased leptin expression as pre-adipocytes matured into adipocytes. Remarkably, leptin expression was stimulated by insulin in adipocytes derived from precursor cells exposed to 5-azacytidine, but suppressed by thiazolidinedione and dexamethasone. In contrast, adipocytes derived from untreated precursor cells were unresponsive to both 5-azacytidine and hormonal stimuli, although lipid accumulation was sufficient to boost leptin expression in the absence of demethylation. Taken together, the results suggest that leptin expression in 3T3-L1 cells requires DNA demethylation prior to adipogenesis, transcriptional activation during adipogenesis, and lipid accumulation after adipogenesis.
Masashi Kuroda and Hiroshi Sakaue : Adipocyte Death and Chronic Inflammation in Obesity, The Journal of Medical Investigation : JMI, Vol.64, No.3,4, 193-196, Aug. 2017.
(Summary)
Cell death is closely linked to many diseases including cancer, neurodegenerative diseases, autoimmune diseases, and metabolic disorders. Increased adipocyte death has been reported during the development of obesity. Adipocyte death may be caused by excessive stress during obesity-related adipose tissue remodeling. Adipose tissue macrophages are key players in obesity-related inflammation and systemic insulin resistance. Accumulating evidence suggests that adipocyte death is involved in immune cell function and initiates inflammation through an interaction with macrophages; however, the precise mechanisms remain largely unknown. This review focuses on the contribution of dead cells (particularly dead adipocytes in adipose tissue) to the pathophysiological conditions associated with obesity. J. Med. Invest. 64: 193-196, August, 2017.
Masashi Kuroda and Hiroshi Sakaue : [Role of vitamin D and calcium in obesity and type 2 diabetes]., Clinical Calcium, Vol.26, No.3, 349-354, Mar. 2016.
(Summary)
Obesity, induced by unhealthy lifestyle choices, could be involved in the development of chronic diseases like type 2 diabete. Obesity is largely due to the imbalance of energy intake and expenditure, therefore we have put more emphasis on the amount of macronutrients including carbohydrates, fats and proteins as dietary therapy for obesity and related-conditions. On the other hand, several studies revealed obese or diabetic patients were more likely to have micronutrient deficiencies such as vitamins and minerals. Besides the effects on bone metabolism, vitamin D and calcium might contribute to metabolic disorder accompanied by obesity. However, it has not been concluded supplementation of these two nutrients has a benefit in obese or diabetic individuals. Further studies are needed.
(Keyword)
Animals / calcium / Diabetes Mellitus, Type 2 / Dietary Proteins / Energy Intake / Humans / obesity / vitamin D
Masashi Kuroda, Naho Ugawa, Etsuko Ishikawa, Yasuyo Kawabata, Saya Okamoto, Waka Sasaki, Saeko Masumoto, Rie Tsutsumi and Hiroshi Sakaue : Transcription factor IRF7 and energy metabolism, The 11th Scientific Meeting of the Asian Association for the Study of Diabetes., May 2019.
2.
Masashi Kuroda : Adipose tissue-derived protein, MFG-E8, regulates chronic inflammation and obesity-related liver disease, Asia-Pacific Diabetes and Obesity Study Group symposium 2018, 兵庫県神戸市, Oct. 2018.
Proceeding of Domestic Conference:
1.
Mayu Sebe, Rie Tsutsumi, Satoka Senoura, Jun Kishi, Masashi Kuroda, 木下 成三, Yutaka Nakaya, Yasuo Tsutsumi, Yasuhiko Nishioka and Hiroshi Sakaue : 飽和脂肪酸の過剰摂取は関節リウマチ病態の憎悪・骨格筋量の減少を引き起こす, 第23回日本病態栄養学会年次学術集会, Jan. 2020.
2.
Kana Takeji, Yuki Yamasaki, Maika Kawai, Yuka Matsumoto, Masashi Kuroda, Rie Tsutsumi and Hiroshi Sakaue : ストレプドゾトシン抵抗性ラットにおける膵β細胞保護因子の探索, 第23回日本病態栄養学会年次学術集会, Jan. 2020.