MyD88-dependent and -independent signaling by IL-1 in neurons probed by bifunctional Toll/IL-1 receptor domain/BB-loop mimetics

Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2953-8. doi: 10.1073/pnas.0510802103. Epub 2006 Feb 13.

Abstract

Interleukin (IL)-1beta is a pluripotent proinflammatory cytokine that signals through the type-I IL-1 receptor (IL-1RI), a member of the Toll-like receptor family. In hypothalamic neurons, binding of IL-1beta to IL-1RI mediates transcription-dependent changes that depend on the recruitment of the cytosolic adaptor protein myeloid differentiation primary-response protein 88 (MyD88) to the IL-1RI/IL-1 receptor accessory protein (IL-1RAcP) complex through homomeric Toll/IL-1 receptor (TIR)-TIR interactions. Through design and synthesis of bifunctional TIR mimetics that disrupt the interaction of MyD88 with the IL-1RI/IL-1RAcP complex, we analyzed the involvement of MyD88 in the signaling of IL-1beta in anterior hypothalamic neurons. We show here that IL-1beta-mediated activation of the protein tyrosine kinase Src depended on a MyD88 interaction with the IL-1RI/IL-1RAcP complex. The activation of the protein kinase Akt/PKB depended on the recruitment of the p85 subunit of PI3K to IL-1RI and independent of MyD88 association with the IL-1RI/IL-1RAcP complex. These bifunctional TIR-TIR mimetics represent a class of low-molecular-weight compounds with both an antiinflammatory and neuroprotective potential. These compounds have the potential to inhibit the MyD88-dependent proinflammatory actions of IL-1beta, while permitting the potential neuronal survival supporting actions mediated by the MyD88-independent activation of the protein kinase Akt.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / antagonists & inhibitors*
  • Adaptor Proteins, Signal Transducing / chemistry
  • Animals
  • Anti-Inflammatory Agents / chemical synthesis
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / pharmacology*
  • Biomimetic Materials / chemical synthesis
  • Biomimetic Materials / chemistry
  • Biomimetic Materials / pharmacology*
  • Interleukin-1 / antagonists & inhibitors*
  • Interleukin-1 / pharmacology
  • Mice
  • Myeloid Differentiation Factor 88
  • Neurons / drug effects*
  • Neurons / enzymology
  • Phosphatidylinositol 3-Kinases / metabolism
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-akt / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptors, Interleukin-1 / antagonists & inhibitors
  • Receptors, Interleukin-1 / chemistry
  • Signal Transduction / drug effects
  • Toll-Like Receptors / antagonists & inhibitors
  • Toll-Like Receptors / chemistry
  • src-Family Kinases / drug effects
  • src-Family Kinases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Anti-Inflammatory Agents
  • Interleukin-1
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • Receptors, Interleukin-1
  • Toll-Like Receptors
  • Phosphatidylinositol 3-Kinases
  • src-Family Kinases
  • Proto-Oncogene Proteins c-akt