Hepatitis C virus variants resistant to macrocyclic NS3-4A inhibitors subvert IFN-β induction by efficient MAVS cleavage

J Hepatol. 2015 Apr;62(4):779-84. doi: 10.1016/j.jhep.2014.11.009. Epub 2014 Nov 21.

Abstract

Background & aims: The hepatitis C virus (HCV) NS3-4A protease is essential for the HCV life cycle and a prime target of antiviral treatment strategies. Protease inhibitors, however, are limited by emergence of resistance-associated amino acid variants (RAVs). The capacity to cleave and inactivate mitochondrial antiviral-signaling protein (MAVS) in the RIG-I-signaling pathway is a cardinal feature of NS3-4A, by which HCV blocks induction of interferon-(IFN)-β, thereby promoting viral persistence. Here, we aimed to investigate the impact of NS3-4A RAVs on MAVS cleavage.

Methods: The impact of NS3-4A RAVs on MAVS cleavage was assessed using immunoblot analyses, luciferase reporter assays and molecular dynamics simulations to study the underlying molecular principles. IFN-β was quantified in serum from patients with different NS3-4A RAVs.

Results: We show that macrocyclic NS3-4A RAVS with substitutions at residue D168 of the protease result in an increased capacity of NS3-4A to cleave MAVS and suppress IFN-β induction compared with a comprehensive panel of RAVs and wild type HCV. Mechanistically, we show the reconstitution of a tight network of electrostatic interactions between protease and the peptide substrate that allows much stronger binding of MAVS to D168 RAVs than to the wild-type protease. Accordingly, we could show IFN-β serum levels to be lower in patients with treatment failure due to the selection of D168 variants compared to R155 RAVs.

Conclusions: Our data constitutes a proof of concept that the selection of RAVs against specific classes of direct antivirals can lead to the predominance of viral variants with possibly adverse pathogenic characteristics.

Keywords: All-oral therapy; Cardif; Direct-acting antiviral agent; Innate immunity; RIG-I signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Antiviral Agents / pharmacology*
  • Cell Culture Techniques
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases / metabolism*
  • Drug Resistance, Viral / immunology
  • Genotype
  • Hepacivirus* / pathogenicity
  • Hepacivirus* / physiology
  • Hepatitis C, Chronic* / immunology
  • Hepatitis C, Chronic* / metabolism
  • Hepatitis C, Chronic* / virology
  • Humans
  • Interferon-beta / metabolism*
  • RNA Helicases / metabolism
  • RNA, Viral
  • Serine Endopeptidases / metabolism
  • Viral Nonstructural Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Antiviral Agents
  • MAVS protein, human
  • NS3 protein, hepatitis C virus
  • RNA, Viral
  • Viral Nonstructural Proteins
  • Interferon-beta
  • Serine Endopeptidases
  • DDX58 protein, human
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases
  • RNA Helicases