Role of MyD88 in adenovirus keratitis

Immunol Cell Biol. 2017 Jan;95(1):108-116. doi: 10.1038/icb.2016.73. Epub 2016 Aug 16.

Abstract

Pattern recognition receptors (PRRs) are critical to the early detection and innate immune responses to pathogens. In particular, the toll-like receptor (TLR) system and its associated adaptor proteins have essential roles in early host responses to infection. Epidemic keratoconjunctivitis, caused by the human adenovirus, is a severe ocular surface infection associated with corneal inflammation (stromal keratitis). We previously showed that adenovirus capsid was a key molecular pattern in adenovirus keratitis, with viral DNA having a lesser role. We have now investigated the role of the adaptor molecule MyD88 in a mouse model of adenovirus keratitis in which there is no viral replication. In MyD88-/- mice infected with human adenovirus type 37, clinical keratitis was markedly reduced, along with infiltration of CD45+ cells, and expression of inflammatory cytokines. Reduction of inflammatory cytokines was also observed in infected primary human corneal fibroblasts pretreated with a MyD88 inhibitory peptide. Keratitis similar to wild type mice was observed in TLR2, TLR9 and IL-1R knockout mice, but was reduced in TLR2/9 double knockout mice, consistent with synergy of TLR2 and TLR9 in the response to adenovirus infection. MyD88 co-immunoprecipitated with Src kinase in mice corneas and in human corneal fibroblasts infected with adenovirus, and MyD88 inhibitory peptide reduced Src phosphorylation, linking MyD88 activation to inflammatory gene expression through a signaling cascade previously shown to be directed by Src. Our findings reveal a critical role for the PRRs TLR2 and 9, and their adaptor protein MyD88, in corneal inflammation upon adenovirus infection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • A549 Cells
  • Adenoviridae / genetics
  • Adenoviridae / physiology*
  • Adenoviridae Infections / metabolism*
  • Adenoviridae Infections / pathology*
  • Adenoviridae Infections / virology
  • Animals
  • Cornea / pathology
  • Cornea / virology
  • Female
  • Humans
  • Keratitis / metabolism*
  • Keratitis / pathology
  • Keratitis / virology*
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myeloid Differentiation Factor 88 / metabolism*
  • Receptors, Interleukin-1 / metabolism
  • Toll-Like Receptor 2 / metabolism
  • Toll-Like Receptor 9 / metabolism
  • Virus Internalization
  • src-Family Kinases / metabolism

Substances

  • Myeloid Differentiation Factor 88
  • Receptors, Interleukin-1
  • Toll-Like Receptor 2
  • Toll-Like Receptor 9
  • src-Family Kinases