Reactive Oxygen Species Produced by HBV Help in Replication and Autophagy in Host Cells

Abstract

Background and Aim: Hepatitis B Virus (HBV) is responsible for liver cirrhosis, fibrosis and hepatocellular carcinoma (HCC) worldwide. HBV modulates many cellular and molecular factors in host cells for its replication and survival including, ROS is considered to inhibit the cellular antioxidants and SIRT-1 expression. However, the exact molecular mechanisms involved in the ROS-induced autophagy and HBV replication has been not known. Methods: HepG2.2.15 cells (Hep G2 cells expressing HBV genome stably) were treated with the NAC (20 μm) overnight. Western blotting was performed for the proteins Sirt-1, HBx, p-akt, akt, p-mTOR, mTOR, Beclin-1, LC-3, ATG5, and β-actin using specific primary antibodies, followed by secondary antibodies and subsequent detection using ECL reagent. Analysis of ROS was performed using the H2-DCFDA in fluoresce microscopy. Autophagy assay was done using the Cyto-ID autophagy detection kit. Determination of the HBsAg was performed by ELISA and HBV-DNA was analysed using the Real-Time PCR method. Results: HBV infection increased the ROS production and formation of autophagic bodies was observed in the cells. Addition of the NAC (antioxidant) inhibited both the autophagy and ROS production in HepG2.2.1.5 cells via modulation of the Beclin-1, LC-3 and ATG-5 expression. HBV transfection also induced the SIRT-1 expression which was inhibited by the addition of the NAC and sirt-1 Si-RNA. Inhibition of the SIRT-1 expression by NAC or Si-RNA inhibited the viral replication and HBV-induced autophagy. Conclusions: In this present study we have shown that HBV infection Leads to the over-expression of SIRT-1, responsible for Autophagy and viral replication in host cells, which was be inhibited by NAC treatment. These data may provide a possibility of ROS inhibition and its therapeutic applications for HBV therapy. The authors have none to declare.