Hepatic miR20b promotes nonalcholic fatty liver diseases by targeting PPARα

Nuclear receptors (NRs) play a crucial role in non-alcoholic fatty liver disease (NAFLD) and have been widely studied(Tran et al. 2018). However, the underlying mechanisms of NR regulation remain largely unclear. Here, we show that miR-20b plays a key role in modulating PPARα, a master regulator of nutrient metabolism and energy homeostasis in the pathogenesis of fatty liver(Wahli et al. 1995; Dongiovanni and Valenti 2013). Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in NAFLD patients, we revealed that miR-20b directly targets PPARα. The expression of miR-20b was remarkably upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of miR-20b dramatically increased hepatic lipid accumulation and plasma triglyceride levels. Furthermore, miR-20b significantly reduced fatty acid oxidation and mitochondrial biogenesis by directly targeting PPARα. Fenofibrate, a specific agonist of PPARα, lost its ability to ameliorate hepatic steatosis in miR-20b-introduced mice. Finally, inhibition of miR-20b dramatically increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Taken together, these results demonstrate that the novel miR-20b directly targets PPARα, plays a significant role in hepatic lipid metabolism, and presents an opportunity for the development of novel therapeutics for NAFLD. Analysis of differential expression (DE) caused by over expression (mimic) of hsa-miR-20b