吉野　純 (ヨシノ　ジュン)

Yoshino, Jun

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医学部 未病対策食共同研究講座 （信濃町）

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特任准教授（有期）
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  • SIRT1 selectively exerts the metabolic protective effects of hepatocyte nicotinamide phosphoribosyltransferase

    Higgins C.B., Mayer A.L., Zhang Y., Franczyk M., Ballentine S., Yoshino J., DeBosch B.J.

    Nature Communications （Nature Communications)  13 （ 1 ） 1074 2022年12月

    ISSN  2041-1723

    　概要を見る

    Calorie restriction abates aging and cardiometabolic disease by activating metabolic signaling pathways, including nicotinamide adenine dinucleotide (NAD+) biosynthesis and salvage. Nicotinamide phosphoribosyltransferase (NAMPT) is rate-limiting in NAD+ salvage, yet hepatocyte NAMPT actions during fasting and metabolic duress remain unclear. We demonstrate that hepatocyte NAMPT is upregulated in fasting mice, and in isolated hepatocytes subjected to nutrient withdrawal. Mice lacking hepatocyte NAMPT exhibit defective FGF21 activation and thermal regulation during fasting, and are sensitized to diet-induced glucose intolerance. Hepatocyte NAMPT overexpression induced FGF21 and adipose browning, improved glucose homeostasis, and attenuated dyslipidemia in obese mice. Hepatocyte SIRT1 deletion reversed hepatocyte NAMPT effects on dark-cycle thermogenesis, and hepatic FGF21 expression, but SIRT1 was dispensable for NAMPT insulin-sensitizing, anti-dyslipidemic, and light-cycle thermogenic effects. Hepatocyte NAMPT thus conveys key aspects of the fasting response, which selectively dissociate through hepatocyte SIRT1. Modulating hepatocyte NAD+ is thus a potential mechanism through which to attenuate fasting-responsive disease.

  • Worksite-based intensive lifestyle therapy has profound cardiometabolic benefits in people with obesity and type 2 diabetes

    Yoshino M., Yoshino J., Smith G.I., Stein R.I., Bittel A.J., Bittel D.C., Reeds D.N., Sinacore D.R., Cade W.T., Patterson B.W., Cho K., Patti G.J., Mittendorfer B., Klein S.

    Cell Metabolism （Cell Metabolism)  34 （ 10 ） 1431 - 1441.e5 2022年10月

    ISSN  15504131

    　概要を見る

    Lifestyle therapy (energy restriction and exercise) is the cornerstone of therapy for people with type 2 diabetes (T2D) but is difficult to implement. We conducted an 8-month randomized controlled trial in persons with obesity and T2D (17 women and 1 man) to determine the therapeutic effects and potential mechanisms of intensive lifestyle therapy on cardiometabolic function. Intensive lifestyle therapy was conducted at the worksite to enhance compliance and resulted in marked (17%) weight loss and beneficial changes in body fat mass, intrahepatic triglyceride content, cardiorespiratory fitness, muscle strength, glycemic control, β cell function, and multi-organ insulin sensitivity, which were associated with changes in muscle NAD+ biosynthesis, sirtuin signaling, and mitochondrial function and in adipose tissue remodeling. These findings demonstrate that intensive lifestyle therapy provided at the worksite has profound therapeutic clinical and physiological effects in people with T2D, which are likely mediated by specific alterations in skeletal muscle and adipose tissue biology.

  • Nicotinamide Mononucleotide Prevents Retinal Dysfunction in a Mouse Model of Retinal Ischemia/Reperfusion Injury

    Lee D., Tomita Y., Miwa Y., Shinojima A., Ban N., Yamaguchi S., Nishioka K., Negishi K., Yoshino J., Kurihara T.

    International Journal of Molecular Sciences （International Journal of Molecular Sciences)  23 （ 19 ）  2022年10月

    ISSN  16616596

    　概要を見る

    Retinal ischemia/reperfusion (I/R) injury can cause severe vision impairment. Retinal I/R injury is associated with pathological increases in reactive oxygen species and inflammation, resulting in retinal neuronal cell death. To date, effective therapies have not been developed. Nicotinamide mononucleotide (NMN), a key nicotinamide adenine dinucleotide (NAD+) intermediate, has been shown to exert neuroprotection for retinal diseases. However, it remains unclear whether NMN can prevent retinal I/R injury. Thus, we aimed to determine whether NMN therapy is useful for retinal I/R injury-induced retinal degeneration. One day after NMN intraperitoneal (IP) injection, adult mice were subjected to retinal I/R injury. Then, the mice were injected with NMN once every day for three days. Electroretinography and immunohistochemistry were used to measure retinal functional alterations and retinal inflammation, respectively. The protective effect of NMN administration was further examined using a retinal cell line, 661W, under CoCl2-induced oxidative stress conditions. NMN IP injection significantly suppressed retinal functional damage, as well as inflammation. NMN treatment showed protective effects against oxidative stress-induced cell death. The antioxidant pathway (Nrf2 and Hmox-1) was activated by NMN treatment. In conclusion, NMN could be a promising preventive neuroprotective drug for ischemic retinopathy.

  • Silencing alanine transaminase 2 in diabetic liver attenuates hyperglycemia by reducing gluconeogenesis from amino acids

    Martino M.R., Gutiérrez-Aguilar M., Yiew N.K.H., Lutkewitte A.J., Singer J.M., McCommis K.S., Ferguson D., Liss K.H.H., Yoshino J., Renkemeyer M.K., Smith G.I., Cho K., Fletcher J.A., Klein S., Patti G.J., Burgess S.C., Finck B.N.

    Cell Reports （Cell Reports)  39 （ 4 ） 110733 2022年04月

    ISSN  2211-1247

    　概要を見る

    Hepatic gluconeogenesis from amino acids contributes significantly to diabetic hyperglycemia, but the molecular mechanisms involved are incompletely understood. Alanine transaminases (ALT1 and ALT2) catalyze the interconversion of alanine and pyruvate, which is required for gluconeogenesis from alanine. We find that ALT2 is overexpressed in the liver of diet-induced obese and db/db mice and that the expression of the gene encoding ALT2 (GPT2) is downregulated following bariatric surgery in people with obesity. The increased hepatic expression of Gpt2 in db/db liver is mediated by activating transcription factor 4, an endoplasmic reticulum stress-activated transcription factor. Hepatocyte-specific knockout of Gpt2 attenuates incorporation of 13C-alanine into newly synthesized glucose by hepatocytes. In vivo Gpt2 knockdown or knockout in liver has no effect on glucose concentrations in lean mice, but Gpt2 suppression alleviates hyperglycemia in db/db mice. These data suggest that ALT2 plays a significant role in hepatic gluconeogenesis from amino acids in diabetes.

  • Intestinal Epithelial NAD<sup>+</sup>Biosynthesis Regulates GLP-1 Production and Postprandial Glucose Metabolism in Mice

    Nagahisa T., Yamaguchi S., Kosugi S., Homma K., Miyashita K., Irie J., Yoshino J., Itoh H.

    Endocrinology (United States) （Endocrinology (United States))  163 （ 4 ）  2022年04月

    ISSN  00137227

    　概要を見る

    Obesity is associated with perturbations in incretin production and whole-body glucose metabolism, but the precise underlying mechanism remains unclear. Here, we tested the hypothesis that nicotinamide phosphoribosyltransferase (NAMPT), which mediates the biosynthesis of nicotinamide adenine dinucleotide (NAD+), a key regulator of cellular energy metabolism, plays a critical role in obesity-associated intestinal pathophysiology and systemic metabolic complications. To this end, we generated a novel mouse model, namely intestinal epithelial cell-specific Nampt knockout (INKO) mice. INKO mice displayed diminished glucagon-like peptide-1 (GLP-1) production, at least partly contributing to reduced early-phase insulin secretion and postprandial hyperglycemia. Mechanistically, loss of NAMPT attenuated the Wnt signaling pathway, resulting in insufficient GLP-1 production. We also found that diet-induced obese mice had compromised intestinal NAMPT-mediated NAD+ biosynthesis and Wnt signaling pathway, associated with impaired GLP-1 production and whole-body glucose metabolism, resembling the INKO mice. Finally, administration of a key NAD+ intermediate, nicotinamide mononucleotide (NMN), restored intestinal NAD+ levels and obesity-associated metabolic derangements, manifested by a decrease in ileal Proglucagon expression and GLP-1 production as well as postprandial hyperglycemia in INKO and diet-induced obese mice. Collectively, our study provides mechanistic and therapeutic insights into intestinal NAD+ biology related to obesity-associated dysregulation of GLP-1 production and postprandial hyperglycemia.

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  • 脂肪細胞ＮＡＤ合成系を標的としたトランスレーショナル型研究の展開

    2021年04月
    -
    2024年03月

    文部科学省・日本学術振興会, 科学研究費助成事業, 吉野 純, 国際共同研究加速基金（帰国発展研究）, 補助金,  研究代表者

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  • ＭＣＢ

    2023年度

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