title: Melanoma differentiation-associated gene 5 (MDA5) is involved in the innate immune response to Paramyxoviridae infection in vivo.
abstract: The early host response to pathogens is mediated by several distinct pattern recognition receptors. Cytoplasmic RNA helicases including RIG-I and MDA5 have been shown to respond to viral RNA by inducing interferon (IFN) production. Previous in vitro studies have demonstrated a direct role for MDA5 in the response to members of the Picornaviridae, Flaviviridae and Caliciviridae virus families ((+) ssRNA viruses) but not to Paramyxoviridae or Orthomyxoviridae ((-) ssRNA viruses). Contrary to these findings, we now show that MDA5 responds critically to infections caused by Paramyxoviridae in vivo. Using an established model of natural Sendai virus (SeV) infection, we demonstrate that MDA5(-/-) mice exhibit increased morbidity and mortality as well as severe histopathological changes in the lower airways in response to SeV. Moreover, analysis of viral propagation in the lungs of MDA5(-/-) mice reveals enhanced replication and a distinct distribution involving the interstitium. Though the levels of antiviral cytokines were comparable early during SeV infection, type I, II, and III IFN mRNA expression profiles were significantly decreased in MDA5(-/-) mice by day 5 post infection. Taken together, these findings indicate that MDA5 is indispensable for sustained expression of IFN in response to paramyxovirus infection and provide the first evidence of MDA5-dependent containment of in vivo infections caused by (-) sense RNA viruses.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Leonid
authors.initials: L
authors.lastname: Gitlin
authors.forename: Loralyn
authors.initials: L
authors.lastname: Benoit
authors.forename: Christina
authors.initials: C
authors.lastname: Song
authors.forename: Marina
authors.initials: M
authors.lastname: Cella
authors.forename: Susan
authors.initials: S
authors.lastname: Gilfillan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Holtzman
authors.forename: Marco
authors.initials: M
authors.lastname: Colonna
mesh_terms: D000818:Animals; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000276:immunology*; D005434:Flow Cytometry; D015870:Gene Expression; D020869:Gene Expression Profiling; D007113:Immunity, Innate; D000072640:Interferon-Induced Helicase, IFIH1; D007372:Interferons / Q000096:biosynthesis / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018184:Paramyxoviridae Infections / Q000276:immunology; D010253:Respirovirus Infections / Q000235:genetics / Q000276:immunology*; D029082:Sendai virus / Q000276:immunology
chemical_list: D007372:Interferons; C510592:Ifih1 protein, mouse; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1