RESUMEN
Persistent infection with hepatitis C virus (HCV) often causes chronic hepatitis, and then shows a high rate of progression to liver cirrhosis and hepatocellular carcinoma. To clarify the mechanism of the persistent HCV infection is considered to be important for the discovery of new target(s) for the development of anti-HCV strategies. In the present study, we found that the expression level of annexin A1 (ANXA1) in human hepatoma cell line Li23-derived D7 cells was remarkably lower than that in parental Li23 cells, whereas the susceptibility of D7 cells to HCV infection was much higher than that of Li23 cells. Therefore, we hypothesized that ANXA1 negatively regulates persistent HCV infection through the inhibition of viral RNA replication. The results revealed that HCV production was significantly inhibited without a concomitant reduction in the amount of lipid droplets in the D7 cells stably expressing exogenous ANXA1. Further, we demonstrated that ANXA1 negatively regulated the step of viral RNA replication rather than that of viral entry in human hepatocytes. These results suggest that ANXA1 would be a novel target for the development of anti-HCV strategies.
Asunto(s)
Anexina A1/fisiología , Hepacivirus/fisiología , ARN Viral/fisiología , Replicación Viral/fisiología , Anexina A1/genética , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/virología , Línea Celular Tumoral , Susceptibilidad a Enfermedades/fisiopatología , Regulación Neoplásica de la Expresión Génica/fisiología , Regulación Viral de la Expresión Génica/fisiología , Hepacivirus/genética , Humanos , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/virología , ARN Viral/genética , Replicación Viral/genéticaRESUMEN
During persistent infection of HCV, the HCV core protein (HCV-JFH-1 strain of genotype 2a) is recruited to lipid droplets (LDs) for viral assembly, but the mechanism of recruitment of the HCV core protein is uncertain. Here, we demonstrated that one of the Ras-related small GTPases, Rab18, was required for trafficking of the core protein around LDs. The knockdown of Rab18 reduced intracellular and extracellular viral infectivity, but not intracellular viral replication in HCV-JFH-1-infected RSc cells (an HuH-7-derived cell line). Exogenous expression of Rab18 increased extracellular viral infectivity almost two-fold. Furthermore, Rab18 was co-localized with the core protein in HCV-JFH-1-infected RSc cells, and the knockdown of Rab18 blocked recruitment of the HCV-JFH-1 core protein to LDs. These results suggest that Rab18 has an important role in viral assembly through the trafficking of the core protein to LDs.
