This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Regarding AIDS, The theme is the desire to gain a detailed understanding of the molecular mechanisms underlying the progression from chronic HCV infection to end-stage liver disease, including cirrhosis and hepatocellular carcinoma. SUMMARY Approximately 170 million individuals worldwide are infected with HCV and in the United States, there are approximately 4 million infected individuals and over 10,000 HCV associated deaths annually. The most remarkable aspect of HCV is its striking ability to persist in the infected host, which often leads to progressive liver disease including fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma. In fact, severe liver damage due to chronic HCV infection is the most common indication for liver transplantation in the United States and Europe. The urgent need for more effective antiviral therapeutics is clearly indicated by the small percentage of patients responding to current treatment of chronic HCV with interferon-alpha (IFN-alpha) in combination with ribavirin or a newly approved pegylated form of interferon plus ribavirin. Unfortunately, HCV research has been hampered by the lack of an adequate tissue culture system, or an effective animal model for HCV infection. As a result, the mechanisms of HCV replication and pathogenesis remain poorly understood, and little is known about the underlying mechanisms leading to the liver injury that often results from HCV infection. To gain a better understanding of HCV replication and pathogenesis, we propose to use the AMT tag approach to study changes in the liver proteome during HCV infection and HCV-associated liver disease using in vivo and in vitro model systems. We have completed the first large scale proteomic analysis of a full length HCV replicon model system for in vitro analysis of HCV replication. Consistent with the literature, we identified HCV-associated expression changes of proteins involved in lipid metabolism thus, demonstrating the utility of multidimensional proteome analysis for assisting in the determination of proteins/pathways affected by HCV infection. We have begun to extend these analyses to biopsies of post-transplanted liver from HCV-infected patients. Preliminary quantitative experiments comparing biopsy samples from a patient who progressed to fibrosis (stage 4) versus one who did not (stage 0) have identified perturbations in relative protein abundance common to both patients (e.g. down-regulated cytoskeletal components) as well as patient-specific changes (e.g. components of lipid metabolism and oxidative stress). Our major objective moving forward is to extend these analyses to biopsy samples from a larger patient cohort (from both the liver transplant model and non-transplant setting) in order to identify changes in relative protein abundance that translate into meaningful protein profiling patterns associated with HCV infection and fibrosis progression. The final results of these studies should increase our understanding of the mechanisms of HCV replication and pathogenesis and may provide critical markers for both diagnostic and prognostic applications as well as suggest novel targets for therapeutic and prophylactic intervention.
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