[HTML][HTML] Reduced miR-200b and miR-200c expression contributes to abnormal hepatic lipid accumulation by stimulating JUN expression and activating the …

J Guo, W Fang, L Sun, Y Lu, L Dou, X Huang, M Sun… - Oncotarget, 2016 - ncbi.nlm.nih.gov
J Guo, W Fang, L Sun, Y Lu, L Dou, X Huang, M Sun, C Pang, J Qu, G Liu, J Li
Oncotarget, 2016ncbi.nlm.nih.gov
Previous studies indicated that miR-200s participated in IL-6-induced hepatic insulin
resistance. However, the role of miR-200s in hepatic lipid accumulation has not been
elucidated. Here we found that miR-200b and miR-200c were reduced in the steatotic livers
of mice fed a high-fat diet (HFD) and patients with nonalcoholic fatty liver disease. This down-
regulation was accompanied by an increase in the expression of lipogenic proteins such as
sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FAS). The …
Abstract
Previous studies indicated that miR-200s participated in IL-6-induced hepatic insulin resistance. However, the role of miR-200s in hepatic lipid accumulation has not been elucidated. Here we found that miR-200b and miR-200c were reduced in the steatotic livers of mice fed a high-fat diet (HFD) and patients with nonalcoholic fatty liver disease. This down-regulation was accompanied by an increase in the expression of lipogenic proteins such as sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FAS). The suppression of miR-200b and miR-200c in Hep1-6 and NCTC1469 hepatocytes enhanced intracellular triglyceride levels, which were associated with increased SREBP-1 and FAS protein levels. In contrast, the over-expression of miR-200b and miR-200c suppressed lipid accumulation and reduced the expression of SREBP1 and FAS in Hep1-6 and NCTC1469 cells transfected with miR-200b or miR-200c mimics. Importantly, the up-regulation of miR-200b and miR-200c could reverse oleic acid/palmitic acid-induced lipid accumulation in hepatocytes. A luciferase reporter assay identified that miR-200b and miR-200c could directly bind the 3′ UTR of jun. JUN activated the transcription of srebp1 to increase lipid accumulation. The data also demonstrated that increased miR-200b and miR-200c expression might be associated with sitagliptin-reduced hepatic lipid accumulation in mice fed a HFD. These findings suggest, for the first time, that reduced miR-200b and miR-200c expression contributes to abnormal hepatic lipid accumulation by stimulating JUN expression and activating the transcription of srebp1.
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