Recently published literature and our unpublished data suggests that HCV may develop several mechanisms to counter the effects of interferon (IFN) and ribavirin, the only therapy available for hepatitis C. The understanding of the mechanism of viral resistance to IFN and ribavirin is important in order to not only understand the mechanism by which recovery or non-recovery from chronic infection occurs during treatment, but also for future improvement in these therapies and the development of new antiviral therapy. Our group has unique collections of serum and liver biopsy samples from patients who received alpha interferon monotherapy, ribavirin monotherapy, or alpha interferon combined with ribavirin, thus allowing critical examination of the clinical significance of these potential mechanisms of viral resistance. The following specific aims will be pursued.
Specific Aim 1 : Examine the E2 and HS5a sequences in patients who are virological IFN-responders (including end-of-treatment responders and sustained responders) and non-responders (including patients with virologic breakthrough during therapy). The focus will be on the PKR, eIF2alpha-homology domain (PePHD) of E2 and the interferon- sensitivity-determining region (ISDR) of ns5a.
Specific Aim 2 : Examine the ns5b sequences in patients who have undergone ribavirin-monotherapy, including ALT responders and non- responders (all of them, nevertheless, are virological non-responders).
Specific Aim 3 : Examine the E2, ns5a and ns5b sequences of patients who have undergone IFN and ribavirin combination therapy. Virological responders (including the end-of-treatment responders and sustained responders) and non-responders (including patients with virologic breakthrough during therapy).

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program--Cooperative Agreements (U19)
Project #
5U19AI040038-07
Application #
6648529
Study Section
Special Emphasis Panel (ZAI1)
Project Start
2002-09-01
Project End
2003-06-30
Budget Start
Budget End
Support Year
7
Fiscal Year
2002
Total Cost
Indirect Cost
Name
University of Southern California
Department
Type
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90033
Liu, Helene Minyi; Aizaki, Hideki; Machida, Keigo et al. (2012) Hepatitis C virus translation preferentially depends on active RNA replication. PLoS One 7:e43600
Machida, Keigo; McNamara, George; Cheng, Kevin T-H et al. (2010) Hepatitis C virus inhibits DNA damage repair through reactive oxygen and nitrogen species and by interfering with the ATM-NBS1/Mre11/Rad50 DNA repair pathway in monocytes and hepatocytes. J Immunol 185:6985-98
Machida, Keigo; Liu, Jian-Chang; McNamara, George et al. (2009) Hepatitis C virus causes uncoupling of mitotic checkpoint and chromosomal polyploidy through the Rb pathway. J Virol 83:12590-600
Machida, Keigo; Tsukamoto, Hidekazu; Mkrtchyan, Hasmik et al. (2009) Toll-like receptor 4 mediates synergism between alcohol and HCV in hepatic oncogenesis involving stem cell marker Nanog. Proc Natl Acad Sci U S A 106:1548-53
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Lai, Chao-Kuen; Jeng, King-Song; Machida, Keigo et al. (2008) Hepatitis C virus NS3/4A protein interacts with ATM, impairs DNA repair and enhances sensitivity to ionizing radiation. Virology 370:295-309
Aswad, Fred; Dennert, Gunther (2006) P2X7 receptor expression levels determine lethal effects of a purine based danger signal in T lymphocytes. Cell Immunol 243:58-65
Kawamura, Hiroki; Aswad, Fred; Minagawa, Masahiro et al. (2006) P2X7 receptors regulate NKT cells in autoimmune hepatitis. J Immunol 176:2152-60
Machida, Keigo; Cheng, Kevin T-H; Lai, Chao-Kuen et al. (2006) Hepatitis C virus triggers mitochondrial permeability transition with production of reactive oxygen species, leading to DNA damage and STAT3 activation. J Virol 80:7199-207
Dennert, Gunther; Aswad, Fred (2006) The role of NKT cells in animal models of autoimmune hepatitis. Crit Rev Immunol 26:453-73

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