miR-125b-5p regulates FFA-induced hepatic steatosis in L02 cells by targeting estrogen-related receptor alpha

BACKGROUND & AIMS: NAFLD is a global and complex liver disease caused by multiple factors. Intrahepatocellular steatosis is the primary prerequisite for the occurrence and development of NAFLD. It has been shown that miR-125b-5p is highly correlated with NAFLD, and ESRRA is a factor that regulates lipid metabolism. The purpose of our study is to investigate whether miR-125b-5p regulates FFA-induced steatosis in L02 cells by targeting ESRRA. APPROACHES AND RESULTS: Estrogen-related receptor alpha (ESRRA) was identified as a direct target of miR-125b-5p through database prediction and a dual-luciferase reporter gene assay. L02 cells were induced with free fatty acids (OA:PA, 2:1) at concentrations of 0.3 mM, 0.6 mM, 0.9 mM, 1.2 mM and 1.5 mM for 24 h, 48 h and 72 h, respectively. The degree of hepatocyte steatosis and triglyceride content were separately manifested by oil red O staining and colorimetric method. Cell viability per group was detected by CCK-8 assay. Eventually, 0.9 mM and 24 h were screened out as the optimal concentration and time for establishing the in-vitro model of hepatic steatosis. Followingly, miR-125b-5p and ESRRA were knocked down by transient transfection. We monitored the expressions of lipid metabolism factors SREBP-1c, ACC1 and FAS and determine triglyceride content within the cells per group. The data showed that knockdown of ESRRA led to down-regulation of the expressions of SREBP-1, ACC1, FAS and triglyceride content. Meanwhile, knockdown of ESRRA and miR-125b-5p resulted that the expressions of ESRRA, SREBP-1, ACC1, FAS and triglyceride content rebounded. CONCLUSIONS: MiR-125b-5p down-regulates the expressions of lipid metabolism-related factors by negatively regulating ESRRA, thereby improving hepatic steatosis.