Hepatocytes Treated with HBV X Protein as Cytotoxic Effectors Kill Primary Hepatocytes by TNF-Alpha-Related Apoptosis-Induced Ligand-Mediated Mechanism

Abstract

Objective: To investigate the effect of HBV X protein (HBX) on TNF-α-related apoptosis-induced ligand (TRAIL) expression in HepG2 cells, and observe death of primary hepatocytes induced by HBX-transfected HepG2 cells. Methods: Western blot was used to detect the TRAIL expression in HepG2 cells transfected with mammalian expression plasmid pSG5UTPL-HBX. The reverse transcription-PCR was used to observe TRAIL mRNA transcription stimulated by HBX protein, and chromium release assay was used to detect death of primary hepatocyte induced by HBX-transfected HepG2 cells. Results: HBX could increase TRAIL expression and mRNA transcription in HepG2 cells in a dose-dependent manner. The C-terminal truncated version of HBX (HBXD1) is responsible for inducing TRAIL expression in HepG2 cells. Chromium release assay results showed that HBX-transfected HepG2 cells kill primary human hepatocytes by a TRAIL-mediated mechanism. Neutralizing anti-TRAIL inhibits the HepG2 killing. Conclusion: HBX protein increases TRAIL expression in HepG2 cells which induced death of primary hepatocytes. HBX protein may play an important role in mechanisms of hepatic cell death and hepatic inflammation caused by HBV infection.