The TLR-independent DNA recognition pathway in murine macrophages: Ligand features and molecular signature

Eur J Immunol. 2009 Jul;39(7):1929-36. doi: 10.1002/eji.200939344.

Abstract

Recognition of foreign DNA by cytosolic innate immune receptors triggers the production of IFN-beta. However, it is unclear whether different types of DNA ligands are recognized by similar receptors and whether the resulting response is distinct from the endosomal TLR response. To address these questions, we compared the two most commonly used types of DNA ligands (IFN-stimulatory DNA (ISD) and poly(dAdT)) and assessed the minimal structural requirements for stimulatory capacity in RAW264.7 cells. Gene expression signatures and competition experiments suggest that ISD and poly(dAdT) are qualitatively indistinguishable and differ from the CpG-containing oligonucleotides triggering the TLR9 pathway. Structure - activity relationship analyses revealed that a minimal length of two helical turns is sufficient for ISD-mediated IFN-beta induction, while phosphorylation at the 5'-end is dispensable. Altogether, our data suggest that, in murine macrophages, only one major cytosolic DNA recognition pathway is operational.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chemokine CXCL11 / genetics
  • CpG Islands / genetics
  • DNA / genetics*
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression / drug effects
  • Immunoblotting
  • Interferon-beta / genetics*
  • Interferon-beta / metabolism
  • Intracellular Signaling Peptides and Proteins
  • Lipopolysaccharides / pharmacology
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • Mice
  • Monomeric GTP-Binding Proteins / genetics
  • Oligonucleotide Array Sequence Analysis
  • Oligonucleotides / genetics
  • Phosphorylation
  • Poly dA-dT / genetics
  • Proteins / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Serpins / genetics
  • Signal Transduction*
  • Toll-Like Receptor 9 / metabolism*
  • Transfection

Substances

  • Chemokine CXCL11
  • Cxcl11 protein, mouse
  • Ifit3 protein, mouse
  • Intracellular Signaling Peptides and Proteins
  • Lipopolysaccharides
  • Oligonucleotides
  • Proteins
  • Serpins
  • Tgtp protein, mouse
  • Tlr9 protein, mouse
  • Toll-Like Receptor 9
  • Poly dA-dT
  • Interferon-beta
  • DNA
  • Monomeric GTP-Binding Proteins