Hepatitis C Virus E1 Protein Enhances Macrophage iNOS Expression In-vitro

Abstract

Interferon-γ (IFN-γ) is a key cytokine in the adaptive immune response that is primarily secreted from CD4+ T helper cells to induce Cytotoxic T lymphocyte (CTL) cell response against HCV infection. IFN-γ activates macrophages in the liver resulting in inhibition of viral replication and increased NO production. HCV-infected macrophages are major producers of NO in the liver. It is not completely understood how HCV proteins affect iNOS expression and what the role of IFN-γ is in HCV protein expression in HCV-infected macrophages. Objective: Evaluate hepatitis C virus proteins’ regulation of IFN-γ-activated macrophage cell line. Methods: RAW-264.7 cells were seeded in 6 well-plates and transfected with HCV protein expressing plasmids using lipofectamine. After treating with IFN-γ, we determined the iNOS and HCV core, NS5A and E1 protein expression with immunoblotting. Results: Consistent with other studies, HCV core and NS5A proteins induced iNOS expression in macrophages. Moreover, HCV E1 protein-enhanced iNOS expression is highest in the presence and absence of IFN-γ activation. Conclusion: These results indicate that hepatitis C virus core, NS5A, E1 protein regulates iNOS protein expression in IFN-γ-activated and resting macrophage cell lines. These findings point to a future research direction for understanding the pathogenesis of HCV-related liver inflammation.