Expression of hepatitis C virus NS5A natural mutants in a hepatocytic cell line inhibits the antiviral effect of interferon in a PKR-independent manner

• Published in: Hepatology (Baltimore, Md.) Vol. 33; no. 6; pp. 1503 - 1511
• Main Authors: Podevin, Philippe, Sabile, Abdelmajid, Gajardo, Rodrigo, Delhem, Nadira, Abadie, Annie, Lozach, Pierre-Yves, Beretta, Laura, Bréchot, Christian
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Elsevier Inc 01.06.2001; W.B. Saunders; Wiley-Blackwell
• Subjects: 2',5'-Oligoadenylate Synthetase - genetics; 3T3 Cells; Amino Acid Sequence - genetics; Animals; Antiviral Agents - antagonists & inhibitors; Cell Division - physiology; Cell Line; Cell Survival - physiology; eIF-2 Kinase - genetics; eIF-2 Kinase - physiology; Gene Expression; GTP-Binding Proteins; Hepatocytes - physiology; Humans; Interferon-alpha - antagonists & inhibitors; Life Sciences; Mice; Microbiology and Parasitology; Molecular Sequence Data; Mutation - genetics; Myxovirus Resistance Proteins; Precipitin Tests; Proteins - genetics; Rats; Tissue Distribution; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - metabolism; Virology
• ISSN: 0270-9139; 1527-3350
• DOI: 10.1053/jhep.2001.24749

The impact of hepatitis C virus NS5A protein mutations on interferon alfa (IFN-α) signaling pathway, cell proliferation, and viability is an important issue that is still under debate. We have therefore combined transient and stable expression in a human hepatocytic cell line (Huh7) of 3 full-length NS5A sequences, isolated from patients with or without response to IFN-α therapy. Expression of all 3 NS5A-reduced IFN-α global antiviral activity on both vesicular stomatitis virus (VSV) and encephalomyocarditis virus (EMCV) replication. We did not show, however, an effect of these 3 NS5A proteins on double-stranded RNA–dependent kinase (PKR) expression and activity as well as colocalization and coimmunoprecipitation between NS5A and PKR. We also failed to show an effect of the 3 NS5A mutants tested on cell proliferation and viability. Overall, our results support an important role of NS5A in controlling IFN-α antiviral activity; they show, however, that PKR-independent mechanisms are implicated, at least in liver-derived cells. (HEPATOLOGY 2001;33:1503-1511.)