Critical role of RIG-I and MDA5 in early and late stages of Tulane virus infection

J Gen Virol. 2017 May;98(5):1016-1026. doi: 10.1099/jgv.0.000769. Epub 2017 May 22.

Abstract

Human noroviruses are a major cause of acute gastroenteritis worldwide, but the lack of a robust cell culture system or small animal model have hampered a better understanding of innate immunity against these viruses. Tulane virus (TV) is the prototype virus of a tentative new genus, Recovirus, in the family Caliciviridae. Its epidemiology and biological properties most closely resemble human norovirus. The host innate immune response to RNA virus infection primarily involves pathogen-sensing toll-like receptors (TLRs) TLR3 and TLR7 and retinoic acid-inducible gene I-like receptor RIG-I and melanoma differentiation associated gene 5 (MDA5). In this study, by using siRNA knockdown, we report that TV infection in LLC-MK2 cells results in an early [3 h post infection (h p.i.), P<0.05] RIG-I-dependent and type I interferon-mediated antiviral response, whereas an MDA5-mediated antiviral effect was observed at later (12 h p.i.; P<0.05) stages of TV replication. Induction of RIG-I and MDA5 was critical for inhibition of TV replication. Furthermore, pre-activation of the RIG-I/MDA5 pathway prevented TV replication (>900-fold decrease; P<0.05), suggesting that RIG-I and MDA5 ligands could be used to develop novel preventive and therapeutic measures against norovirus.

MeSH terms

  • Animals
  • Caliciviridae / immunology*
  • Caliciviridae Infections / immunology*
  • DEAD Box Protein 58 / metabolism*
  • Gene Knockdown Techniques
  • Host-Pathogen Interactions*
  • Immunity, Innate*
  • Interferon-Induced Helicase, IFIH1 / metabolism*
  • Macaca mulatta
  • Virus Replication*

Substances

  • DEAD Box Protein 58
  • Interferon-Induced Helicase, IFIH1