Upregulation of microRNA-328-3p by hepatitis B virus contributes to THLE-2 cell injury by downregulating FOXO4

Background Hepatitis B virus (HBV) remains a major cause of chronic hepatitis and hepatocellular carcinoma, and miRNAs play important roles in HBV pathogenesis. Our previous study has shown that miR-328-3p is upregulated in HBV-infected patients and serves as a potent predictor for the prognosis of HBV-related liver failure. Methods Here, the role of miR-328-3p in modulating cell injury in HBV-infected liver cells THLE-2 was investigated in detail. MiR-328-3p expression was examined using qRT-PCR. The levels of pro-inflammatory cytokines were measured using ELISA. HBV RNA and HBV DNA levels were quantified. The interactions between STAT3 and miR-328-3p promoter as well as miR-328-3p and FOXO4 were analyzed using chromatin immunoprecipitation (CHIP) assay and luciferase reporter assay, respectively. THLE-2 cell injury was evaluated by examining cell viability and apoptosis. Results HBV promoted expression of miR-328-3p through the STAT3 signal pathway and that increasingly expressed miR-328-3p downregulated its target FOXO4, leading to the promotion of cell injury in HBV-infected liver cells THLE-2. Conclusion These data demonstrate that HBV-STAT3-miR-328-3p-FOXO4 regulation pathway may play an important role in the pathogenesis of HBV infection.