HIV Vpr Stimulates Hepatitis C Virus RNA Replication And Protein Expression Through Up-regulating MiR-122Transcription

Background and Aims:Co-infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is common due to shared transmission routes. In HIV/HCV co-infected patients, the frequency of HCV related cirrhosis and HCC are higher than the HCV mono-infected patients. Epidemiological data have demonstrated that HIV/HCV co-infection is characterized by higher serum HCVRNA loads compared to HCV mono-infection, strongly suggesting that HIV stimulates HCV replication, and it may be the major mechanism by which HIV accelerates HCV related liver diseases. However, the mechanisms by which the enhancement of HIV on HCV replication in HIV/HCV co-inefected patients are unknown. Some HIV proteins have been reported to play important roles in the impact of HIV on HCV replication. It is known that Vpr is an important auxiliary protein in HIV infection. Vpr mediates the nuclear transport of pre-integration complex (PIC), and then facilitates the HIV-1infection in undivided cells. In addition, Vpr protein activates the HIV-1long terminal repeat sequence (LTR) as well as other host gene promoters, induces cell cycle arrest in the G2phase, and also regulates the activity of NF-κB. In this study, we sought to investigate the effect of Vpr on HCV replication, to explore the regulatory mechanism by Vpr, and aimed to providing a new insight for HIV impact on HCV replication.Methods:By using HCV5’UTR-driven luciferase reporter gene and miR-122promoter luciferase reporter system, two HCV infectious cell models (HCV JFH1infection cell model and OR6cell model), fluorescence quantitative PCR, western blotting and luciferase assays, we assesed Vpr effect on HCV RNA replication and protein expression. Dual luciferase assay was performed to evaluate HCV5’UTR activity mediated by Vpr. In addition, the miR-122promoter activity, precursor miR-122and mature miR-122levels were assessed by dual luciferase assay and realtime PCR. By use of the miR-122inhibitor, we explored the mechanism by which Vpr regulated HCV5’UTR activity, HCV RNA replication and protein expression.Results:It was found that Vpr enhanced HCV5’-UTR driven luciferase expression in a dose dependent manner, and in Molt-4cells and Huh7.5.1cell co-culture model, we found that Vpr could secrete from lymphocytes, and then enter into hepatocytes. In addition, we found that Vpr up-regulated HCV RNA replication and protein expression in JFH1-infected Huh7.5.1cells and OR6cells. In stable Vpr-expressing cells JFH1replicated more efficiently than in control cells. Furthermore, we demonstrated that Vpr up-regulated miR-122expression by activating promoter activity and RNA transcription. Inhibition of miR-122by miR-122inhibitor significantly blocked the HCV5’-UTR activity mediated by Vpr, and we also found a similar decrease in HCVRNA replication and HCV protein expression as that caused by Vpr.Conclusions:Our results demonstrate that HIV Vpr stimulates miR-122expression and then activates HCV5’-UTR, suggesting it is a major mechanism HIV Vpr employed to stimulate HCV replication, and those results provided a new research direction for HIV impact on HCV replication.