Mechanism of up-regulation of human Toll-like receptor 3 secondary to infection of measles virus-attenuated strains

Biochem Biophys Res Commun. 2003 Nov 7;311(1):39-48. doi: 10.1016/j.bbrc.2003.09.159.

Abstract

PolyI:C, a synthetic double-stranded (ds)RNA, and viruses act on cells to induce IFN-beta which is a key molecule for anti-viral response. Although dsRNA is a virus-specific signature and a ligand for human Toll-like receptor 3 (TLR3), largely uncharacterized multiple pathways associate virus-mediated IFN-beta induction. Here, we demonstrated that laboratory-adapted but not wild-type strains of measles virus (MV) up-regulated TLR3 expression both in dendritic cells and epithelial cell line A549. The kinetics experiments with the laboratory MV strain revealed that TLR3 was induced late compared to IFN-beta and required new protein synthesis. Furthermore, neutralizing antibodies against IFN-beta or IFNAR (Interferon-alpha/beta receptor) suppressed MV-induced TLR3 induction, indicating that type I IFN, IFN-alpha/beta, is critical for MV-mediated TLR3 induction. Yet, a recently identified virus-inducible IFN, the IFN-lambda, did not contribute to TLR3 expression. A virus-responsive element that up-regulates TLR3 was identified in the TLR3-promoter region by reporter gene experiments. The ISRE, a recently reported site for IFN-beta induction, but not STAT binding site, located around -30bp of TLR3 promoter responded to MV to induce TLR3 expression. This further indicates the importance of type I IFN for TLR3 up-regulation in the case of viral infection. In HeLa and MRC5 cells, augmented production of IFN-beta was observed in response to dsRNA when TLR3 had been induced beforehand. Thus, the MV-induced expression of TLR3 may reflect amplified IFN production that plays a part in host defense to viral infection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Fibroblasts / immunology
  • Fibroblasts / metabolism
  • Fibroblasts / virology
  • Humans
  • Interferon-beta / immunology*
  • Interferon-beta / metabolism*
  • Measles / immunology
  • Measles / metabolism*
  • Measles virus / classification
  • Measles virus / immunology
  • Measles virus / pathogenicity*
  • Membrane Glycoproteins / classification
  • Membrane Glycoproteins / immunology
  • Membrane Glycoproteins / metabolism*
  • Receptors, Cell Surface / classification
  • Receptors, Cell Surface / immunology
  • Receptors, Cell Surface / metabolism*
  • Respiratory Mucosa / immunology
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / virology
  • Toll-Like Receptor 3
  • Toll-Like Receptors
  • Up-Regulation / physiology*
  • Vaccines, Attenuated

Substances

  • Membrane Glycoproteins
  • Receptors, Cell Surface
  • TLR3 protein, human
  • Toll-Like Receptor 3
  • Toll-Like Receptors
  • Vaccines, Attenuated
  • Interferon-beta