Dataset Information

Replication of subgenomic hepatitis C virus replicons in mouse fibroblasts is facilitated by deletion of interferon regulatory factor 3 and expression of liver-specific microRNA 122.

ABSTRACT: Hepatitis C virus (HCV) infection causes significant morbidity, and efficient mouse models would greatly facilitate virus studies and the development of effective vaccines and new therapeutic agents. Entry factors, innate immunity, and host factors needed for viral replication represent the initial barriers that restrict HCV infection of mouse cells. Experiments in this paper consider early postentry steps of viral infection and investigate the roles of interferon regulatory factors (IRF-3 and IRF-9) and microRNA (miR-122) in promoting HCV replication in mouse embryo fibroblasts (MEFs) that contain viral subgenomic replicons. While wild-type murine fibroblasts are restricted for HCV RNA replication, deletion of IRF-3 alone can facilitate replicon activity in these cells. This effect is thought to be related to the inactivation of the type I interferon synthesis mediated by IRF-3. Additional deletion of IRF-9 to yield IRF-3(-/-) IRF-9(-/-) MEFs, which have blocked type I interferon signaling, did not increase HCV replication. Expression of liver-specific miR-122 in MEFs further stimulated the synthesis of HCV replicons in the rodent fibroblasts. The combined effects of miR-122 expression and deletion of IRF-3 produced a cooperative stimulation of HCV subgenome replication. miR-122 and IRF-3 are independent host factors that are capable of influencing HCV replication, and our findings could help to establish mouse models and other cell systems that support HCV growth and particle formation.

SUBMITTER: Lin LT

PROVIDER: S-EPMC2937658 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Replication of subgenomic hepatitis C virus replicons in mouse fibroblasts is facilitated by deletion of interferon regulatory factor 3 and expression of liver-specific microRNA 122.

Lin Liang-Tzung LT Noyce Ryan S RS Pham Tram N Q TN Wilson Joyce A JA Sisson Gary R GR Michalak Thomas I TI Mossman Karen L KL Richardson Christopher D CD

Journal of virology 20100630 18

Hepatitis C virus (HCV) infection causes significant morbidity, and efficient mouse models would greatly facilitate virus studies and the development of effective vaccines and new therapeutic agents. Entry factors, innate immunity, and host factors needed for viral replication represent the initial barriers that restrict HCV infection of mouse cells. Experiments in this paper consider early postentry steps of viral infection and investigate the roles of interferon regulatory factors (IRF-3 and I ...[more]

PMID: 20592082

Similar Datasets

Project description:The molecular mechanisms of liver pathology and clinical disease in hepatitis E virus (HEV) infection remain unclear. MicroRNAs (miRNAs) are known to modulate viral pathogenesis either by directly altering viral gene expression or by enhancing cellular antiviral responses. Given the importance of microRNA-122 (miR-122) in liver pathobiology, we investigated possible role of miR-122 in HEV infection. In silico predictions using HEV genotype 1 (HEV-1), HEV-2, HEV-3, and HEV-4 sequences showed that the majority of genomes (203/222) harbor at least one miR-122/microRNA-122-3p (miR-122*) target site. Interestingly, HEV-1 genomes showed a highly (97%) conserved miR-122 target site in the RNA-dependent RNA polymerase (RdRp) region (RdRpc). We analyzed the significance of miR-122 target sites in HEV-1/HEV-3 (HEV-1/3) genomes by using a replicon-based cell culture system. HEV infection did not change the basal levels of miR-122 in hepatoma cells. However, transfection of these cells with miR-122 mimics enhanced HEV-1/3 replication and depletion of miR-122 with inhibitors led to suppression of HEV-1/3 replication. Mutant HEV-1 replicons with an altered target RdRpc sequence (CACTCC) showed a drastic decrease in virus replication, whereas introduction of alternative miR-122 target sites in mutant replicons rescued viral replication. There was enrichment of HEV-1 RNA and miR-122 molecules in RNA-induced silencing complexes in HEV-infected cells. Furthermore, pulldown of miR-122 molecules from HEV-infected cells resulted in pulldown of HEV genomic RNA along with miR-122 molecules. These observations indicate that miR-122 facilitates HEV-1 replication, probably via direct interaction with a target site in the viral genome. The positive role of miR-122 in viral replication presents novel opportunities for antiviral therapy and management of hepatitis E.IMPORTANCE Hepatitis E is a problem in both developing and developed countries. HEV infection in most patients follows a self-limited course; however, 20% to 30% mortality is seen in infected pregnant women. HEV superinfections in patients with chronic hepatitis B or hepatitis C virus infections are associated with adverse clinical outcomes, and both conditions warrant therapy. Chronic HEV infections in immunocompromised transplant recipients are known to rapidly progress into cirrhosis. Currently, off-label use of ribavirin (RBV) and polyethylene glycol-interferon (PEG-IFN) as antiviral therapy has shown promising results in both acute and chronic hepatitis E patients; however, the teratogenicity of RBV limits its use during pregnancy, while alpha IFN (IFN-α) increases the risk of transplant rejections. Experimental data determined with genotype 1 virus in the current study show that miR-122 facilitates HEV replication. These observations present novel opportunities for antiviral therapy and management of hepatitis E.

Dataset Information

Replication of subgenomic hepatitis C virus replicons in mouse fibroblasts is facilitated by deletion of interferon regulatory factor 3 and expression of liver-specific microRNA 122.

Publications

Replication of subgenomic hepatitis C virus replicons in mouse fibroblasts is facilitated by deletion of interferon regulatory factor 3 and expression of liver-specific microRNA 122.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets