Replication of hepatitis B virus induces down－regulation of Arid2 expression in hepatoma cells

Abstract:

Objective：To investigate the effects of hepatitis B virus replication on the expression of Arid2 in hepatoma cells. Methods：The HBV-stable or transient expression cell models were used to evaluate the regulatory effects of HBV replication on Arid2 expres－sion. For stable replication model，HepAD38 cells were used to express HBV under the control of inducible tetracycline promoter. For transient expression system，Huh7 cells were infected with the replicative recombinant adenovirus Ad-HBV1.1 carrying 1.1 copies of HBV genome. Southern-blot，ELISA and real-time quantitative PCR were employed to confirm HBV replication efficiency in hepatoma cells. The expression levels of Arid2 gene were determined by RT-PCR and Western blot. To further identify which of the viral-en－coded proteins implicated in the regulation of Arid2 expression，Huh7 cells were transfected with hepatitis B virus S protein（HBs），HBp，hepatitis B virus core protein（HBc） or hepatitis B virus X protein（HBx）-expression plasmids，and Arid2 expression level were determined. Results：HBV viroloigal marker and replicative intermediates were detected both in HBV-stably or transient expression system，indicating that HBV-stably or transiently expression cell model can robustly support HBV replication. The expression levels of Arid2 gene were significantly down-regulated both in the HBV stable replication and transient replication cell model. The protein expression level of Arid2 was decreased by 46.10% in Huh7 cells transfected with Ad-HBV 1.1 and by 37.63% in HepAD38 cells（P<0.05）. Among the four viral-encoded expression plasmids，HBV surface antigen and HBx significantly repressed Arid2 mRNA and protein expression，with inhibitory effects of 54.55% and 46.38%（P<0.05） in protein level by HBs and HBx respec－tively. Conclusion：HBV replication represses Arid2 expression in hepatoma cells. Among viral-encoded proteins，HBs and HBx may play important roles in HBV-induced Arid2 repression.