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en: Development of a screening system for agents that modulate taste receptor expression with the CRISPR-Cas9 system in medaka.

en: Taste recognition mediated by taste receptors is critical for the survival of animals in nature and is an important determinant of nutritional status and quality of life in humans. However, many factors including aging, diabetes, zinc deficiency, infection with influenza or cold viruses, and chemotherapy can trigger dysgeusia, for which a standard treatment has not been established. We here established an engineered strain of medaka (Oryzias latipes) that expresses green fluorescent protein (GFP) from the endogenous taste 1 receptor 3 (T1R3) gene locus with the use of the CRISPR-Cas9 system. This T1R3-GFP knock-in (KI) strain allows direct visualization of expression from this locus by monitoring of GFP fluorescence. The pattern of GFP expression in the T1R3-GFP KI fish thus mimicked that of endogenous T1R3 gene expression. Furthermore, exposure of T1R3-GFP KI medaka to water containing monosodium glutamate or the anticancer agent 5-fluorouracil resulted in an increase or decrease, respectively, in GFP fluorescence intensity, effects that also recapitulated those on T1R3 mRNA abundance. Finally, screening for agents that affect GFP fluorescence intensity in T1R3-GFP KI medaka identified tryptophan as an amino acid that increases T1R3 gene expression. The establishment of this screening system for taste receptor expression in medaka provides a new tool for the development of potential therapeutic agents for dysgeusia.

en: Biochemical and Biophysical Research Communications


en: 生活習慣病と栄養学 : 最近のトピックスを交えて

ja: 生活習慣病と栄養学 : 最近のトピックスを交えて

en: Metabolic syndrome is a pathological condition with hyperglycemia, dyslipidemia, or hypertension resulting in cardiovascular and cerebrovascular disease. Factors that affect visceral fat accumulation and weight gain include not only physiological factors such as heredity, constitution, and age, but also behavioral factors and environmental factors. Eating behavior and eating environment are critical for the prevention and treatment of metabolic syndrome. In this report, we will discuss about recent topics of nutrition in metabolic syndrome, especially association with macronutrients such as carbohydrate, fatty acids and protein. In recent years, several publications have determined the benefit of low carbohydrate diet on obesity and diabetes, and the American Diabetes Association has also recommended low carbohydrate diet, Mediterranean diet, and a diet mainly consistent with vegetables and plants. There have been many reports that the effect of carbohydrate restriction has not only the weight loss effect but also reduces risk factors such as cardiovascular disease and cerebrovascular disease. Fanelli et al . recently have shown that half of US adults with diabetes have less than the recommended daily intake of protein, which may lead to poor dietary quality. Diabetic patients with low protein intake had significantly lower dietary nutrient density and 12．5% higher carbohydrate intake, whereas diabetic patients with daily protein intake meeting the recommended amount have shown that the overall quality of the diet was high and almost met the recommended daily amount of vegetables, whole grains, dairy products and added sugars. Therefore, in addition to the prevention of metabolic syndrome, protein is important for treatment of metabolic syndrome and higher QOL. Nutritional research needs further development to deal with metabolic syndrome.

en: Shikoku Acta Medica

ja: 四国医学雑誌


en: Leucine imparts cardioprotective effects by enhancing mTOR activity and mitochondrial fusion in a myocardial ischemia/reperfusion injury murine model.

en: Leu treatment improved the damage caused by myocardial I/R injury by promoting mTOR activity and mitochondrial fusion on prediabetic hearts in mice.

ja: mice. Additionally, Leu increased the percentage of fused mitochondria and the mitochondrial volume, and decreased the number of mitochondria per cell in isolated cardiomyocytes. In HFD-induced obese mice, Leu treatment significantly reduced infarct size (41.0% ± 1.1% vs. 51.0% ± 1.4%, n = 7, p < 0.05), which was not induced by ischemic preconditioning, and this effect was inhibited by Rap. Furthermore, we observed enhanced mTOR protein expression and mitochondrial fusion with decreased reactive oxygen species production with Leu treatment in HFD-induced obese mice, but not in mTOR

en: Diabetology & Metabolic Syndrome

ja: Diabetology & Metabolic Syndrome


en: Leucine induces cardioprotection in vitro by promoting mitochondrial function via mTOR and Opa-1 signaling.

en: Leu treatment is critical in rendering a cardioprotective effect exhibited by BCAAs via mTOR signaling. Furthermore, Leu improved mitochondrial function.

ja: Cardiac myocytes isolated from adult male Wistar rats were incubated and exposed to simulated I/R (SI/R) injury by replacing the air content. Cardiac myocytes were treated with Leu and subsequently, their survival rate was calculated. To elucidate the signaling pathway and mitochondrial function, immunoblots and mitochondrial permeability transition pore were examined. Cell survival rate was decreased with SI/R but improved by 160 μM Leu (38.5 ± 3.6% vs. 64.5 ± 4.2%, respectively, p < 0.001). Although rapamycin (mTOR inhibitor) prevented this cardioprotective effect induced by Leu, wortmannin (PI3K inhibitor) did not interfere with this effect. In addition, we indicated that overexpression of Opa-1 and mitochondrial function are ameliorated via Leu-induced mitochondrial biogenesis. In contrast, knockdown of Opa-1 suppressed Leu-induced cardioprotection.

en: Nutrition, Metabolism, and Cardiovascular Diseases : NMCD


en: Differential regulation of Actn2 and Actn3 expression during unfolded protein response in C2C12 myotubes.

en: 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.

en: Journal of Muscle Research and Cell Motility


en: Interferon regulatory factor 7 mediates obesity-associated MCP-1 transcription.

en: 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.

en: PLoS ONE

ja: PLoS ONE


en: The PDK1-FoxO1 signaling in adipocytes controls systemic insulin sensitivity through the 5-lipoxygenase-leukotriene B 4 axis

en: 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.

en: Proceedings of the National Academy of Sciences of the United States of America


en: DNA methylation status influences insulin-induced glucose transport in 3T3-L1 adipocytes by mediating p53 expression.

en: 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.

en: Biochemical and Biophysical Research Communications


en: Effect of olive oil consumption on aging in a senescence-accelerated mice-prone 8 (SAMP8) model.

en: 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.

en: The Journal of Medical Investigation : JMI


en: Management of dysgeusia and dysosmia caused by chemotherapy

ja: 化学療法に伴う味覚・嗅覚障害への対応 (特集 化学療法時の栄養管理)

en: がんの化学療法中に味覚・嗅覚障害は頻繁に生じ，患者のquality of life(以下，QOLと略)だけでなく，体重低下や栄養状態の悪化を引き起こす深刻な副作用である．しかしながらこれまで確立された治療法や予防策はなく，食事内容や形態の工夫が主な対処法であった．味覚障害は薬剤による亜鉛のキレート化が原因であるとされているが，これに加えて味覚受容体遺伝子の発現変化や口腔粘膜障害の影響も報告されている．本稿では，化学療法中に生じる味覚・嗅覚障害の実態とともに，これに対する栄養的なアプローチを紹介する．

en: The Journal of Japanese Society for Parenteral and Enteral Nutrition

ja: 日本静脈経腸栄養学会雑誌


en: Readthrough of ACTN3 577X nonsense mutation produces full-length α-actinin-3 protein.

en: 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.

ja: , respectively) and transfected the constructs into HEK293 cells. Similar constructs for the ACTN3 577R gene were used as controls. HEK293 cells carrying the X gene, but not the X

ja: Biochemical and Biophysical Research Communications


en: Effect of Janus kinase inhibition by tofacitinib on body composition and glucose metabolism.

en: 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.

ja: The Journal of Medical Investigation : JMI


en: Endoplasmic Reticulum Stress in Mice Increases Hepatic Expression of Genes Carrying a Premature Termination Codon via a Nutritional Status-Independent GRP78-Dependent Mechanism.

en: Journal of Cellular Biochemistry

ja: Journal of Cellular Biochemistry


en: Ligand-induced rapid skeletal muscle atrophy in HSA-Fv2E-PERK transgenic mice.

en: 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.

en: PLoS ONE


en: Intracerebroventricular injection of ghrelin decreases wheel running activity in rats.

en: 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.

en: Peptides

ja: Peptides


en: DNA Methylation Suppresses Leptin Gene in 3T3-L1 Adipocytes.

en: 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.