Viral persistence, liver disease and host response in Hepatitis C-like virus rat model

ABSTRACT

The lack of a relevant, tractable, and immunocompetent animal model for hepatitis C virus (HCV) has severely impeded investigations of viral persistence, immunity and pathogenesis. In the absence of immunocompetent models with robust HCV infection, homolog hepaciviruses in their natural host could potentially provide useful surrogate models. We isolated a rodent hepacivirus (RHV) from wild rats (Rattus norvegicus), RHV-rn1, acquired the complete viral genome sequence and developed an infectious reverse genetics system. RHV-rn1 resembles HCV in genomic features including the pattern of polyprotein cleavage sites and secondary structures in the viral 5' and 3' UTRs. We used site-directed and random mutagenesis to determine that only the first of the two miR-122 seed sites in viral 5'UTR is required for viral replication and persistence in rats. Next, we used the clone derived virus progeny to infect several inbred and outbred rat strains. Our results determined that RHV-rn1 possesses several HCV-defining hallmarks: hepatotropism, propensity to persist, and the ability of induce gradual liver damage. Histological examination of liver samples revealed the presence of lymphoid aggregates, parenchymal inflammation and macro/micro vesicular steatosis in chronically infected rats. Gene expression analysis demonstrated that the intrahepatic response during RHV-rn1 infection in rats mirrors that of HCV infection, including persistent activation of interferon signaling pathways. Finally, we determined that the backbone drug of HCV direct acting antiviral (DAA) therapy, Sofosbuvir, effectively suppresses chronic RHV-rn1 infection in rats. Taken together, we developed RHV-rn1 infected rats as a fully immunocompetent and informative surrogate model to delineate the mechanisms of HCV-related viral persistence, immunity and pathogenesis. This article is protected by copyright. All rights reserved.

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