Use of human hepatocytes to investigate HCV infection. Methods Mol Biol. 2010;640:447-462. [PMID: 20645067 DOI: 10.1007/978-1-60761-688-7_24]

Mechanisms of HCV-induced liver cancer: what did we learn from in vitro and animal studies?

Hepatitis C virus (HCV) is a cause of liver diseases that range from steatohepatitis, to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The challenge of understanding the pathogenesis of HCV-associated liver cancer is difficult as most standard animal models used in biomedical research are not permissive to HCV infection. Herein, we provide an overview of a number of creative in vivo, mostly in the mouse, and in vitro models that have been developed to advance our understanding of the molecular and cellular effects of HCV on the liver, specifically with their relevance to HCC.

Entry and replication of recombinant hepatitis C viruses in cell culture

Hepatitis C virus (HCV) is a positive-strand enveloped RNA virus and belongs to the Flaviviridae family. The heavy health burden associated with the virus infection in humans and the intriguing peculiarities of the interaction between the HCV replication cycle and the hepatocyte host cell have stimulated a flourishing research field. The present review aims at recapitulating the different viral and cellular systems modelling HCV entry and replication, and in particular at gathering the tools available to dissect the HCV entry pathway.

Persistence of HCV in quiescent hepatic cells under conditions of an interferon-induced antiviral response

BACKGROUND & AIMS

Hepatitis C virus (HCV) is a common cause of chronic liver disease. Many patients do not clear the viral infection; little is known about the mechanisms of HCV persistence or the frequent failure of interferon (IFN) to eliminate it. Better culture systems are needed to study viral replication in quiescent liver cells.

METHODS

We used human hepatoma (Huh7.5) cells and those that had undergone proliferation arrest and differentiation (Huh7.5(dif)) to study the persistence of HCV infection following exposure of the cells to IFN-α and to compare the antiviral effects of IFN-α and IFN-λ. We validated these results with primary human hepatocytes and Huh7 cells that expressed an IFN-inducible fluorophore.

RESULTS

Following infection of Huh7.5(dif) cells, HCV replicated persistently and released infectious particles. Long-term exposure of the cells to IFN-α reduced HCV replication ∼1000-fold but did not eliminate the virus; viral replication rebounded after withdrawal of IFN, as it does in patients with chronic HCV infection. HCV replicated at higher levels, but not exclusively, in cells that had a low level of response to IFN-α. Following incubation of cells with equipotent concentrations of IFN-α or IFN-λ, Huh7.5(dif) cells expressed a wider pattern of IFN-stimulated genes than undifferentiated Huh7.5 cells or primary human hepatocytes, indicating that the antiviral response depends on the differentiation status of the cells.

CONCLUSIONS

We developed a cell culture system using hepatoma cells to study persistent HCV infection during the type I or type III IFN-induced antiviral response. The level and range of the antiviral responses were associated with the differentiation status of the cells. We propose that HCV exploits the stochastic nature of the response of hepatocytes to IFN to sustain persistence.

New advances in the development of experimental models of hepatitis C virus infection

Hepatitis C virus (HCV) infection is another common cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma after hepatitis B virus. It is very difficult to study the variety and replication of HCV and interplay between HCV and the host and to develop new antiviral drugs and vaccines against HCV infection because of lack of susceptible hosts and stable and convenient experimental models of HCV infection. In this paper, we review recent advances in the development of experimental models of HCV infection.