Wogonin inhibits LPS-induced inflammatory responses in rat dorsal root ganglion neurons via inhibiting TLR4-MyD88-TAK1-mediated NF-κB and MAPK signaling pathway

Cell Mol Neurobiol. 2015 May;35(4):523-31. doi: 10.1007/s10571-014-0148-4. Epub 2014 Dec 14.

Abstract

Recent studies showed that the activation of toll-like receptor 4 (TLR4) on dorsal root ganglion (DRG) neurons might underlie neuropathic and inflammatory pain states. This study was undertaken to investigate the effects of wogonin, a flavonoid with potent anti-inflammatory properties on the inflammatory reaction and TLR4 dependent pathways in lipopolysaccharide (LPS)-treated DRG neurons. Our results showed that wogonin not only inhibited the expression and interaction of TLR4, MyD88, and TAK1, but also reduced the activation of nuclear factor kappa B and mitogen-activated protein kinases pathway in LPS-treated DRG neurons. Moreover, wogonin significantly suppressed the release of pro-inflammatory mediators in LPS-induced DRG neurons, including cyclooxygenase-2, inducible nitric oxide synthases, interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha. Our results suggested that pre-treatment with wogonin could attenuate the TLR4-mediated inflammatory response in LPS-induced DRG neurons, thus might be beneficial for the treatment of neuropathic and inflammatory pain.

MeSH terms

  • Animals
  • Flavanones / pharmacology*
  • Ganglia, Spinal / drug effects
  • Ganglia, Spinal / metabolism*
  • Inflammation / pathology*
  • Inflammation Mediators / metabolism
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Lipopolysaccharides / pharmacology*
  • MAP Kinase Kinase Kinases / metabolism
  • MAP Kinase Signaling System / drug effects*
  • Myeloid Differentiation Factor 88 / metabolism
  • NF-kappa B / metabolism*
  • Neurons / drug effects
  • Neurons / metabolism*
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats, Wistar
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism

Substances

  • Flavanones
  • Inflammation Mediators
  • Lipopolysaccharides
  • Myeloid Differentiation Factor 88
  • NF-kappa B
  • RNA, Messenger
  • Toll-Like Receptor 4
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinases
  • MAP kinase kinase kinase 7
  • wogonin