| BackgroundsNon-alcoholic fatty liver disease (NAFLD) is a rapidly increasing liver disorder which spectrum ranges from simple steatosis to NASH, fibrosis and cirrhosis, and even may finally develop into liver failure and liver cancer. The prevalence of NAFLD keeps rising with the dramatic changes in the lifestyle and diet of the global population, and it is predicted that the next epidemic in chronic liver disease is a direct result of NAFLD. Accumulating evidences demonstrate that variety of processes contribute to the pathogenesis of NAFLD, which including insulin resistance, mitochondrial dysfunction, lipid and glucose metabolism. Therefore, the underlying disease mechanisms need to be understood to help the successful management of NAFLD.microRNAs are a class of small non-coding RNAs which act the functions at post-transcriptional level through binding to the3’-untranslated region (3’-UTR) of the target genes. Accumulating evidences support the effects of miRNAs in insulin resistance, lipid and glucose metabolism, providing a potential linkage between the miRNAs and NAFLD. MiR-152is a microRNA we found differently expressed in high-fat diet induced Sprague-Dawley (SD) rats. A recent report has shown that miR-152represses the Wnt signaling pathway and promotes the dysregulation of the cell proliferation. Wingless-type MMTV integration site family (WNTs) is a family of secreted glycoproteins. WNTs plays an important role in metabolic homeostasis, including the regulation of adipogenesis, insulin sensitivity and mitochondrial physiology, which are all partake in the pathogenesis of NAFLD. However, the detail effect on the WNT-dependent biological process is unclear.ObjectiveThe aims of this study were to explore the effect and molecular mechanisms of miR-152on the pathogenesis of NAFLD in HepG2cells and human hepatocytes.MethodsCells were transfected with lentiviral-based hsa-miR-152mimic (Lenti-miR-152), lentiviral-based hsa-miR-152inhibitor (Lenti-152-In) or lentiviral-based negative control (Lenti-NC). Real-time PCR was utilized to detect the miR-152expression. The cell model was established by culturing HepG2cells and human hepatocytes with a high concentration of free fatty acid. Oil Red O staining and TG content were utilized to detect the lipid accumulation in HepG2cells and human hepatocytes. In addition, Wnt10b plasmid and mutant Wnt10b plasmid were constructed for luciferase activity assay. Besides, we examined the expression of candidate genes involved in WNT signaling pathway and lipogenesis (Wnt10b,β-Catenin, GSK-3β, SREBP-1c and PPAR y). And at last, we detected the ATP content and mitochondria DNA levels in HepG2cells.ResultsMiR-152dramatically suppressed the expression of WntlOb. Further analysis confirmed that miR-152bound directly to the3’-untranslated region (3’-UTR) of WntlOb. MiR-152mediated hepatic steatosis through WntlOb and nucleus β-Catenin down-regulation parallel with peroxisome proliferator-activated receptor-y (PPAR-y) and sterol-regulatory element binding protein lc (SREBP-lc) up-regulation. In addition, we also observed impaired mitochondria in HepG2cells in the presence of miR-152.ConclusionmiRNAs may play a critical role in the pathogenesis of NAFLD, and miR-152/Wnt10b pathway could be a potential target for NAFLD prevention and treatment. |
