RIG-I Signaling via MAVS Is Dispensable for Survival in Lethal Influenza Infection In Vivo

Mediators Inflamm. 2018 Nov 8:2018:6808934. doi: 10.1155/2018/6808934. eCollection 2018.

Abstract

Retinoic acid-inducible gene I (RIG-I) is an important regulator of virus-induced antiviral interferons (IFNs) and proinflammatory cytokines. It requires interaction with an adaptor molecule, mitochondrial antiviral-signaling protein (MAVS), to activate downstream signaling pathways. To elucidate the mechanism(s) by which RIG-I-dependent recognition of IAV infection in vivo triggers innate immune responses, we infected mutant mice lacking RIG-I or MAVS with influenza A virus (IAV) and measured their innate immune responses. As has previously been demonstrated with isolated deletion of the virus recognition receptors TLR3, TLR7, and NOD2, RIG-I or MAVS knockout (KO) did not result in higher mortality and did not reduce IAV-induced cytokine responses in mice. Infected RIG-I KO animals displayed similar lung inflammation profiles as did WT mice, in terms of the protein concentration, total cell count, and inflammatory cell composition in the bronchoalveolar lavage fluid. RNA-Seq results demonstrated that all types of mice exhibited equivalent antiviral and inflammatory gene responses following IAV infection. Together, the results indicated that although RIG-I is important in innate cytokine responses in vitro, individual deletion of the genes encoding RIG-I or MAVS did not change survival or innate responses in vivo after IAV infection in mice.

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Bronchoalveolar Lavage
  • DEAD Box Protein 58 / genetics
  • DEAD Box Protein 58 / metabolism*
  • Humans
  • Immunoassay
  • Influenza A virus / pathogenicity*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Knockout
  • Nod2 Signaling Adaptor Protein / genetics
  • Nod2 Signaling Adaptor Protein / metabolism
  • Orthomyxoviridae Infections / genetics
  • Orthomyxoviridae Infections / immunology
  • Orthomyxoviridae Infections / metabolism*
  • Signal Transduction / physiology
  • Toll-Like Receptor 3 / genetics
  • Toll-Like Receptor 3 / metabolism
  • Toll-Like Receptor 7 / genetics
  • Toll-Like Receptor 7 / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • IPS-1 protein, mouse
  • Membrane Glycoproteins
  • Nod2 Signaling Adaptor Protein
  • Nod2 protein, mouse
  • TLR3 protein, mouse
  • Tlr7 protein, mouse
  • Toll-Like Receptor 3
  • Toll-Like Receptor 7
  • Ddx58 protein, mouse
  • DEAD Box Protein 58