A decrease in hepatic microRNA-9 expression impairs gluconeogenesis by targeting FOXO1 in obese mice
A decrease in hepatic microRNA-9 expression impairs gluconeogenesis by targeting FOXO1 in obese mice
复制标题
肥胖小鼠肝脏 microRNA-9 表达的减少通过靶向 FOXO1 损害糖异生
DOI：
10.1007/s00125-016-3932-5
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发表时间：
2016-07-01
期刊：
影响因子：
8.2
通讯作者：
Liang, Xiubin
中科院分区：
文献类型：
--
作者：
Yan, Caifeng;Chen, Jinfeng;Liang, Xiubin
目的/假设MicroRNA-9（miR-9）参与胰腺β细胞功能的调节。然而，其在植物异生中的作用尚不清楚。本研究旨在探讨miR-9在肝脏葡萄糖生成（HGP）中的作用。采用甲基化特异性PCR方法检测肝细胞miR-9- 3启动子区甲基化状态。采用染色质免疫沉淀法（ChIP）和实时荧光定量PCR法检测DNA甲基转移酶（DNMT）1、DNMT 3a和DNMT 3b与miR-9- 3启动子的结合活性。HGP在体外和体内进行了评价。葡萄糖耐量、胰岛素耐量和丙酮酸耐量试验也performed.ResultsReduced miR-9的表达和miR-9- 3启动子的高甲基化在肥胖小鼠的肝脏中观察。进一步的研究表明，在mob/ob小鼠肝细胞中，DNMT 1与miR-9- 3启动子的结合增加，而DNMT 3a和DNMT 3b与miR-9- 3启动子的结合没有增加。DNMT 1的敲除减轻了体内和体外肝脏miR-9表达的降低。过表达肝脏miR-9可改善肥胖小鼠的胰岛素敏感性并抑制HGP。此外，肝脏miR-9的缺失导致瘦小鼠的随机血糖水平和空腹血糖水平升高。重要的是，沉默的叉头盒O 1（FOXO 1）表达逆转了miR-9缺失诱导的肝细胞糖异生和葡萄糖产生。结论/解释我们的观察表明，miR-9表达的减少导致肥胖小鼠糖异生的不适当激活。
Aim/hypothesisMicroRNA-9 (miR-9) is involved in the regulation of pancreatic beta cell function. However, its role in gluconeogenesis is still unclear. Our objective was to investigate the role of miR-9 in hepatic glucose production (HGP).MethodsMiR-9 expression was measured in livers of high-fat diet (HFD) mice andob/obmice. The methylation status of themiR-9-3promoter regions in hepatocytes was determined by the methylation-specific PCR procedure. The binding activity of DNA methyltransferase (DNMT)1, DNMT3a and DNMT3b on themiR-9-3promoter was detected by chromatin immunoprecipitation (ChIP) and quantitative real-time PCR assays. HGP was evaluated in vitro and in vivo. Glucose tolerance, insulin tolerance and pyruvate tolerance tests were also performed.ResultsReduced miR-9 expression and hypermethylation of themiR-9-3promoter were observed in the livers of obese mice. Further study showed that the binding of DNMT1, but not of DNMT3a and DNMT3b, to themiR-9-3promoter was increased in hepatocytes fromob/obmice. Knockdown of DNMT1 alleviated the decrease in hepatic miR-9 expression in vivo and in vitro. Overexpression of hepatic miR-9 improved insulin sensitivity in obese mice and inhibited HGP. In addition, deletion of hepatic miR-9 led to an increase in random and fasting blood glucose levels in lean mice. Importantly, silenced forkhead box O1 (FOXO1) expression reversed the gluconeogenesis and glucose production in hepatocytes induced by miR-9 deletion.Conclusions/interpretationOur observations suggest that the decrease in miR-9 expression contributes to an inappropriately activated gluconeogenesis in obese mice.