Control of antiviral defenses through hepatitis C virus disruption of retinoic acid-inducible gene-I signaling

E Foy, K Li, R Sumpter Jr, YM Loo… - Proceedings of the …, 2005 - National Acad Sciences
E Foy, K Li, R Sumpter Jr, YM Loo, CL Johnson, C Wang, PM Fish, M Yoneyama, T Fujita…
Proceedings of the National Academy of Sciences, 2005National Acad Sciences
Hepatitis C virus (HCV) is a major human pathogen that infects 170 million people. A
hallmark of HCV is its ability to establish persistent infections reflecting the evasion of host
immunity and interference with α/β-IFN innate immune defenses. We demonstrate that
disruption of retinoic acid-inducible gene I (RIG-I) signaling by the viral NS3/4A protease
contributes to the ability of HCV to control innate antiviral defenses. RIG-I was essential for
virus or HCV RNA-induced signaling to the IFN-β promoter in human hepatoma cells. This …
Hepatitis C virus (HCV) is a major human pathogen that infects 170 million people. A hallmark of HCV is its ability to establish persistent infections reflecting the evasion of host immunity and interference with α/β-IFN innate immune defenses. We demonstrate that disruption of retinoic acid-inducible gene I (RIG-I) signaling by the viral NS3/4A protease contributes to the ability of HCV to control innate antiviral defenses. RIG-I was essential for virus or HCV RNA-induced signaling to the IFN-β promoter in human hepatoma cells. This signaling was disrupted by the protease activity of NS3/4A, which ablates RIG-I signaling of downstream IFN regulatory factor 3 and NF-κB activation, attenuating expression of host antiviral defense genes and interrupting an IFN amplification loop that otherwise suppresses HCV replication. Treatment of cells with an active site inhibitor of the NS3/4A protease relieved this suppression and restored intracellular antiviral defenses. Thus, NS3/4A control of RIG-I supports HCV persistence by preventing IFN regulatory factor 3 and NF-κB activation. Our results demonstrate that these processes are amenable to restoration through pharmacologic inhibition of viral protease function.
National Acad Sciences