Over 170 million people world-wide are infected with hepatitis C virus (HCV), a major cause of liver cirrhosis and hepatocellular carcinoma. Despite the global prevalence of HCV, little is known about how this virus interacts with the host and evades the immune system to establish persistent infection. HCV circulates in infected individuals as a heterogeneous population based on buoyant density and this heterogeneity is due in part to virus association with lipoproteins - including very low density (VLDL), low density (LDL) and high density (HDL) lipoproteins. HCV association with lipoproteins initiates during virus particle assembly, and release of progeny HCV is closely linked to the VLDL secretory pathway. Entry into susceptible cells is also facilitated by interaction with lipoproteins, specifically HDL, which promotes rapid kinetics of entry thought to facilitate escape from neutralizing antibodies. Together, these data support the interaction between HCV and lipoproteins and underscore their role in HCV pathogenesis, however, the precise nature of how these lipoproteins interact with HCV is unknown and the full consequences of their interaction not fully explored. Our overall hypothesis is that HCV virion association with, or incorporation of, host proteins and lipids reduces virus susceptibility to neutralization. Previous studies indicate that lipoprotein interaction is mediated by the HCV surface glycoproteins, E1 and E2.
In Specific Aim 1, we will define the specific molecular requirements for lipoprotein (specifically HDL)-HCV interaction using both biochemical assays to dissect the HDL complex and a glycoprotein mutagenesis strategy to identify critical viral residues for binding. Independent of viral infection, lipoproteins have been shown to have immunoregulatory activities, and HDL has specifically been shown to modulate complement activation. Thus, in Specific Aim 2 we will investigate the impact of HCV association with HDL on virus susceptibility to complement-mediated virolysis. Our final Specific Aim is to perform complete proteomic and lipidomic analyses on purified HCV. These data will not only further elucidate the lipoprotein-virus interaction, but will also enable us to catalog the cellular components of the virus particle. Such analyses will provide valuable insight into the composition of the HCV particle and its life cycle.

Public Health Relevance

Over 170 million people world-wide are infected with HCV, a major cause of liver cirrhosis and hepatocellular carcinoma. No licensed vaccine or universally effective therapy is available to date and development of better treatment options will require further understanding of how HCV interacts with the host to establish persistent infection. To address this, the studies outlined in this proposal are designed to define the specific interaction between HCV and host lipoproteins and investigate the impact of this interaction on viral evasion of the host immune system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32AI091207-03
Application #
8298947
Study Section
Special Emphasis Panel (ZRG1-F13-C (20))
Program Officer
Koshy, Rajen
Project Start
2010-07-01
Project End
2013-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
3
Fiscal Year
2012
Total Cost
$52,190
Indirect Cost
Name
Rockefeller University
Department
Microbiology/Immun/Virology
Type
Other Domestic Higher Education
DUNS #
071037113
City
New York
State
NY
Country
United States
Zip Code
10065