Transgenic Mouse Models of hepatitis C Virus Replication

Hepatitis C virus (HCY) is a common cause of chronic hepatitis, infecting approximately 4 million people in the United States and 170 million people worldwide. The vast majority of HCY -infected individuals develop chronic hepatitis C, which can progress to fibrosis, cirrhosis, and hepatocellular carcinoma. The study of the molecular mechanisms ofHCY replication and hepatocarcinogenesis has been hampered by the lack ofa small animal model of HCY replication and infection. Currently, chimpanzee is the only reliable animal susceptible to productive HCY infection and replication. However, the application of chimpanzee model is restricted by its limited resource and high maintenance cost. Our ability to deveop alternative small animal models for HCY replication is constrained by the narrow host range ofHCY infection. Recently, we have made significant advances in genetic studies of HCY replication and development of small murine models ofHCY replication and infection. We have demonstrated that HCY RNA derived from a chromosomally integrated HCY cDNA resulted in robust production of infectious HCY. More importantly, we have found that HCY RNA replicated efficiently in the mouse embryo fibroblasts (MEFs). These advances allow us to hypothesize that the cDNA-derived HCY RNA can replicate efficiently in transgenic mice. The overral goal of this application is to develop transgenic mouse models for HCY RNA replication and to demonstrate HCY RNA replication in transgenic mice. Thus, we will develop multiple transgenic mouse lines that contain the cDNAs of a subgenomic and full-length HCY RNAs and a reversible tetracycline-controlled transcriptional activator (rtT A) and suppressor (tTS). Transcriptional expression of HCY RNA is under the control of a tetracycline-responsive promoter. HCY RNA replication in transgenic mice will be determined by multidiscipline appproaches and will be validated by the use of HCY protease inhibitors and mouse interferons. Development of animal models that recapitulate HCY RNA replication, disease development and progression, and hepatocarcinogenesis wiJl facilitate the determination of the roles and molecular mechanisms of host and viral factors in HCY replication, pathogenesis, and carcinogenesis. Moreover, the availability of transgenic HCY models will accelerate the discovery and development of prophylactic and therapeutic antiviral drugs and vaccines against HCY infection and thereby prevent HCC development.