医学部 内分泌・代謝・糖尿病内科学

村尾 直哉

むらお なおや  (Naoya Murao)

基本情報

所属
藤田医科大学 医学部 内分泌・代謝・糖尿病内科学 助教

研究者番号
70964675
ORCID ID
 https://orcid.org/0000-0002-7424-4476
J-GLOBAL ID
202201000671672632
researchmap会員ID
R000037975

外部リンク

学歴

 4

論文

 14
  • Naoya Murao, Risa Morikawa, Yusuke Seino, Kenju Shimomura, Yuko Maejima, Yuichiro Yamada, Atsushi Suzuki
    bioRxiv 2024年10月17日  筆頭著者責任著者
  • Haruki Fujisawa, Takashi Watanabe, Okiru Komine, Sachiho Fuse, Momoka Masaki, Naoko Iwata, Naoya Murao, Yusuke Seino, Hideyuki Takeuchi, Koji Yamanaka, Makoto Sawada, Atsushi Suzuki, Yoshihisa Sugimura
    Free radical biology & medicine 223 458-472 2024年10月  
    Hyponatremia is the most common clinical electrolyte disorder. Chronic hyponatremia has been recently reported to be associated with falls, fracture, osteoporosis, neurocognitive impairment, and mental manifestations. In the treatment of chronic hyponatremia, overly rapid correction of hyponatremia can cause osmotic demyelination syndrome (ODS), a central demyelinating disease that is also associated with neurological morbidity and mortality. Using a rat model, we have previously shown that microglia play a critical role in the pathogenesis of ODS. However, the direct effect of rapid correction of hyponatremia on microglia is unknown. Furthermore, the effect of chronic hyponatremia on microglia remains elusive. Using microglial cell lines BV-2 and 6-3, we show here that low extracellular sodium concentrations (36 mmol/L decrease; LS) suppress Nos2 mRNA expression and nitric oxide (NO) production of microglia. On rapid correction of low sodium concentrations, NO production was significantly increased in both cells, suggesting that acute correction of hyponatremia partly directly contributes to increased Nos2 mRNA expression and NO release in ODS pathophysiology. LS also suppressed expression and nuclear translocation of nuclear factor of activated T cells-5 (NFAT5), a transcription factor that regulates the expression of genes involved in osmotic stress. Furthermore, overexpression of NFAT5 significantly increased Nos2 mRNA expression and NO production in BV-2 cells. Expressions of Nos2 and Nfat5 mRNA were also modulated in microglia isolated from cerebral cortex in chronic hyponatremia model mice. These data indicate that LS modulates microglial NO production dependent on NFAT5 and suggest that microglia contribute to hyponatremia-induced neuronal dysfunctions.
  • Sachiho Fuse, Haruki Fujisawa, Naoya Murao, Naoko Iwata, Takashi Watanabe, Yusuke Seino, Hideyuki Takeuchi, Atsushi Suzuki, Yoshihisa Sugimura
    Peptides 179 171267-171267 2024年9月  
    Signs and symptoms of hypernatremia largely indicate central nervous system dysfunction. Acute hypernatremia can cause demyelinating lesions similar to that observed in osmotic demyelination syndrome (ODS). We have previously demonstrated that microglia accumulate in ODS lesions and minocycline protects against ODS by inhibiting microglial activation. However, the direct effect of rapid rise in the sodium concentrations on microglia is largely unknown. In addition, the effect of chronic hypernatremia on microglia also remains elusive. Here, we investigated the effects of acute (6 or 24 h) and chronic (the extracellular sodium concentration was increased gradually for at least 7 days) high sodium concentrations on microglia using the microglial cell line, BV-2. We found that both acute and chronic high sodium concentrations increase NOS2 expression and nitric oxide (NO) production. We also demonstrated that the expression of nuclear factor of activated T-cells-5 (NFAT5) is increased by high sodium concentrations. Furthermore, NFAT5 knockdown suppressed NOS2 expression and NO production. We also demonstrated that high sodium concentrations decreased intracellular Ca2+ concentration and an inhibitor of Na+/Ca2+ exchanger, NCX, suppressed a decrease in intracellular Ca2+ concentrations and NOS2 expression and NO production induced by high sodium concentrations. Furthermore, minocycline inhibited NOS2 expression and NO production induced by high sodium concentrations. These in vitro data suggest that microglial activity in response to high sodium concentrations is regulated by NFAT5 and Ca2+ efflux through NCX and is suppressed by minocycline.
  • Naoya Murao, Risa Morikawa, Yusuke Seino, Kenju Shimomura, Yuko Maejima, Tamio Ohno, Norihide Yokoi, Yuichiro Yamada, Atsushi Suzuki
    bioRxiv 2024年8月15日  筆頭著者責任著者
  • Koki Nishida, Shinji Ueno, Yusuke Seino, Shihomi Hidaka, Naoya Murao, Yuki Asano, Haruki Fujisawa, Megumi Shibata, Takeshi Takayanagi, Kento Ohbayashi, Yusaku Iwasaki, Katsumi Iizuka, Shoei Okuda, Mamoru Tanaka, Tadashi Fujii, Takumi Tochio, Daisuke Yabe, Yuuichiro Yamada, Yoshihisa Sugimura, Yoshiki Hirooka, Yoshitaka Hayashi, Atsushi Suzuki
    Nutrients 16(14) 2024年7月14日  
    (1) Background: Proglucagon-derived peptides (PDGPs) including glucagon (Gcg), GLP-1, and GLP-2 regulate lipid metabolism in the liver, adipocytes, and intestine. However, the mechanism by which PGDPs participate in alterations in lipid metabolism induced by high-fat diet (HFD) feeding has not been elucidated. (2) Methods: Mice deficient in PGDP (GCGKO) and control mice were fed HFD for 7 days and analyzed, and differences in lipid metabolism in the liver, adipose tissue, and duodenum were investigated. (3) Results: GCGKO mice under HFD showed lower expression levels of the genes involved in free fatty acid (FFA) oxidation such as Hsl, Atgl, Cpt1a, Acox1 (p < 0.05), and Pparα (p = 0.05) mRNA in the liver than in control mice, and both FFA and triglycerides content in liver and adipose tissue weight were lower in the GCGKO mice. On the other hand, phosphorylation of hormone-sensitive lipase (HSL) in white adipose tissue did not differ between the two groups. GCGKO mice under HFD exhibited lower expression levels of Pparα and Cd36 mRNA in the duodenum as well as increased fecal cholesterol contents compared to HFD-controls. (4) Conclusions: GCGKO mice fed HFD exhibit a lesser increase in hepatic FFA and triglyceride contents and adipose tissue weight, despite reduced β-oxidation in the liver, than in control mice. Thus, the absence of PGDP prevents dietary-induced fatty liver development due to decreased lipid uptake in the intestinal tract.

MISC

 25

共同研究・競争的資金等の研究課題

 3