title: Inhibition of dsRNA-induced signaling in hepatitis C virus-infected cells by NS3 protease-dependent and -independent mechanisms.
abstract: The recent establishment of a robust hepatitis C virus (HCV) cell culture system permits analysis of virus-host interactions during HCV infection. Here, we report that HCV genotype 2a (JFH-1) infection fails to induce IFN-beta or IFN-stimulated gene expression in Huh-7 cells, and that it blocks IFN-beta and IFN-stimulated gene production after transfection of synthetic dsRNA. Overexpression of individual components of the dsRNA-signaling pathway in HCV-infected and uninfected cells indicates that HCV inhibits IFN-beta promoter activity by inactivating the mitochondrial antiviral signaling protein/IFN-beta promoter stimulator 1 (MAVS/IPS-1), while leaving the IFN-induced Janus kinases-signal transducers and activators of transcription (JAK-STAT) signaling pathway intact. We also show that MAVS/IPS-1-dependent IFN-beta promoter activity in HCV-infected cells is fully restored by the nonstructural protein 3 (NS3) protease inhibitor BILN2061. In contrast, synthetic dsRNA-induced IFN-beta promoter activity is not restored by BILN2061, although it is partially restored by overexpression of RIG-I. These results support recently reported evidence that the HCV NS3 protease blunts the ability of HCV to induce IFN-beta promoter activity by proteolytically cleaving MAVS/IPS-1. The results also suggest that HCV blocks the synthetic dsRNA-induced signaling pathway at a point upstream of MAVS/IPS-1, and that it does so by an NS3-independent mechanism.
authors.affiliation: Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Guofeng
authors.initials: G
authors.lastname: Cheng
authors.forename: Jin
authors.initials: J
authors.lastname: Zhong
authors.forename: Francis V
authors.initials: FV
authors.lastname: Chisari
mesh_terms: D021581:Active Transport, Cell Nucleus; D002219:Carbamates / Q000494:pharmacology; D045744:Cell Line, Tumor; D015967:Gene Expression Regulation, Viral; D016174:Hepacivirus / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism; D050832:Interferon-Stimulated Gene Factor 3 / Q000235:genetics / Q000378:metabolism; D016899:Interferon-beta / Q000096:biosynthesis; D047028:Macrocyclic Compounds / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011480:Protease Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000276:immunology* / Q000502:physiology; D020218:Response Elements / Q000235:genetics; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D002219:Carbamates; D051550:I-kappa B Kinase; D050838:Interferon Regulatory Factor-3; D050832:Interferon-Stimulated Gene Factor 3; D016899:Interferon-beta; D047028:Macrocyclic Compounds; D011480:Protease Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011804:Quinolines; D012330:RNA, Double-Stranded; D013844:Thiazoles; D017361:Viral Nonstructural Proteins; C479555:BILN 2061; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C403191:TBK1 protein, human