Downregulation of miR-181a upregulates sirtuin-1 (SIRT1) and improves hepatic insulin sensitivity
Downregulation of miR-181a upregulates sirtuin-1 (SIRT1) and improves hepatic insulin sensitivity
复制标题
miR-181a 的下调会上调 Sirtuin-1 (SIRT1) 并提高肝脏胰岛素敏感性
DOI：
10.1007/s00125-012-2539-8
复制
发表时间：
2012-07-01
期刊：
影响因子：
8.2
通讯作者：
Zhai, Q. W.
中科院分区：
文献类型：
--
作者：
Zhou, B.;Li, C.;Zhai, Q. W.
Sirtuin-1（SIRT 1）是对抗胰岛素抵抗和2型糖尿病的潜在治疗靶点。本研究旨在寻找一种靶向SIRT 1的调节肝脏胰岛素敏感性的microRNA（miRNAs）。方法采用荧光素酶结合突变和免疫印迹技术筛选并验证生物信息学预测的miRNAs。通过实时PCR测量miRNA和mRNA水平。通过免疫印迹和糖原合成检测胰岛素信号传导。使用腺病毒、抑制剂和SIRT 1缺陷肝细胞研究了SIRT 1的参与。结果miR-181 a通过miR-181 a结合位点靶向SIRT 1 mRNA的3′非翻译区（3′UTR），在翻译水平下调SIRT 1蛋白的丰度。miR-181 a在胰岛素抵抗培养的肝细胞和肝脏以及糖尿病患者的血清中增加。miR-181 a的过表达降低SIRT 1蛋白水平和活性，并导致肝细胞胰岛素抵抗。通过反义寡核苷酸抑制miR-181 a增加SIRT 1蛋白水平和活性，并改善肝细胞中的胰岛素敏感性。SIRT 1的异位表达消除了miR-181 a对胰岛素敏感性的影响，抑制SIRT 1活性或SIRT 1缺陷显著减弱了反义miR-181 a诱导的胰岛素敏感性改善。此外，腺病毒过表达miR-181 a会损害肝脏胰岛素信号传导，腹腔注射miR-181 a的锁核酸反义寡核苷酸可改善饮食诱导的肥胖小鼠的葡萄糖稳态。抑制miR-181 a可能是治疗胰岛素抵抗和2型糖尿病的一个潜在的新策略。
Aims/hypothesisSirtuin-1 (SIRT1) is a potential therapeutic target to combat insulin resistance and type 2 diabetes. This study aims to identify a microRNA (miRNA) targeting SIRT1 to regulate hepatic insulin sensitivity.MethodsLuciferase assay combined with mutation and immunoblotting was used to screen and verify the bioinformatically predicted miRNAs. miRNA and mRNA levels were measured by real-time PCR. Insulin signalling was detected by immunoblotting and glycogen synthesis. Involvement of SIRT1 was studied with adenovirus, inhibitor and SIRT1-deficient hepatocytes. The role of miR-181a in vivo was explored with adenovirus and locked nucleic acid antisense oligonucleotides.ResultsmiR-181a targets the 3′ untranslated region (3′UTR) of Sirt1 mRNA through a miR-181a binding site, and downregulates SIRT1 protein abundance at the translational level. miR-181a is increased in insulin-resistant cultured hepatocytes and liver, and in the serum of diabetic patients. Overexpression of miR-181a decreases SIRT1 protein levels and activity, and causes insulin resistance in hepatic cells. Inhibition of miR-181a by antisense oligonucleotides increases SIRT1 protein levels and activity, and improves insulin sensitivity in hepatocytes. Ectopic expression of SIRT1 abrogates the effect of miR-181a on insulin sensitivity, and inhibition of SIRT1 activity or SIRT1 deficiency markedly attenuated the improvement in insulin sensitivity induced by antisense miR-181a. In addition, overexpression of miR-181a by adenovirus impairs hepatic insulin signalling, and intraperitoneal injection of locked nucleic acid antisense oligonucleotides for miR-181a improves glucose homeostasis in diet-induced obesity mice.Conclusions/interpretationmiR-181a regulates SIRT1 and improves hepatic insulin sensitivity. Inhibition of miR-181a might be a potential new strategy for treating insulin resistance and type 2 diabetes.