TBK1-targeted suppression of TRIF-dependent signaling pathway of Toll-like receptors by 6-shogaol, an active component of ginger

Biosci Biotechnol Biochem. 2009 Jul;73(7):1474-8. doi: 10.1271/bbb.80738. Epub 2009 Jul 7.

Abstract

Toll-like receptors (TLRs) are primary sensors that detect a wide variety of microbial components involving induction of innate immune responses. After recognition of microbial components, TLRs trigger the activation of myeloid differential factor 88 (MyD88) and Toll-interleukin-1 (IL-1) receptor domain-containing adapter inducing interferon-beta (TRIF)-dependent downstream signaling pathways. 6-Shoagol, an active ingredient of ginger, inhibits the MyD88-dependent signaling pathway by inhibiting inhibitor-kappaB kinase activity. Inhibitor-kappaB kinase is a key kinase in nuclear factor kappaB (NF-kappaB) activation. However, it is not known whether 6-shogaol inhibits the TRIF-dependent signaling pathway. Our goal was to identify the molecular target of 6-shogaol in the TRIF-dependent pathway of TLRs. 6-Shogaol inhibited the activation of interferon-regulatory factor 3 (IRF3) induced by lipopolysaccharide (LPS) and by polyriboinosinic polyribocytidylic acid (poly[I:C]), overexpression of TRIF, TANK-binding kinase1 (TBK1), and IRF3. Furthermore, 6-shogaol inhibited TBK1 activity in vitro. Together, these results suggest that 6-shogaol inhibits the TRIF-dependent signaling pathway of TLRs by targeting TBK1, and, they imply that 6-shogaol can modulate TLR-derived immune/inflammatory target gene expression induced by microbial infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Animals
  • Catechols / pharmacology*
  • Cattle
  • Cell Line
  • Enzyme Activation / drug effects
  • Humans
  • Mice
  • NF-kappa B / metabolism
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / metabolism*
  • Signal Transduction / drug effects*
  • Toll-Like Receptors / metabolism*
  • Zingiber officinale / chemistry*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Catechols
  • NF-kappa B
  • Toll-Like Receptors
  • shogaol
  • Protein Serine-Threonine Kinases