Xanthoceraside inhibits pro-inflammatory cytokine expression in Aβ25-35/IFN-γ-stimulated microglia through the TLR2 receptor, MyD88, nuclear factor-κB, and mitogen-activated protein kinase signaling pathways

J Pharmacol Sci. 2013;122(4):305-17. doi: 10.1254/jphs.13031fp.

Abstract

An accumulating body of evidence suggests that Alzheimer's disease (AD) is associated with microglia-mediated neuroinflammation and pro-inflammatory cytokine expression. Therefore, the suppression of neuroinflammation and pro-inflammatory cytokine might theoretically slow down the progression of AD. Xanthoceraside, a novel triterpenoid saponin extracted from the husks of Xanthoceras sorbifolia Bunge, has potent antiinflammatory and neuroprotective effects. However, the molecular mechanism underlying its anti-inflammatory action remains unclear. In the present study, we attempted to determine the effects of xanthoceraside on the production of pro-inflammatory mediators in amyloid β25-35 (Aβ25-35)/interferon-γ (IFN-γ)-stimulated microglia. Our results indicated that xanthoceraside (0.01 and 0.1 μM) significantly inhibited the release of nitric oxide (NO) and pro-inflammatory cytokines interleukin-1β and tumor necrosis factor-α in a concentration-dependent manner. Reverse transcriptase-polymerase chain reaction and western blotting analyses showed that xanthoceraside decreased the Aβ25-35/IFN-γ-induced production of cyclooxygenase-2 and inducible NO synthase. These effects were accompanied by inhibited activities of nuclear factor-κB and mitogen-activated protein kinase through Toll-like receptor 2 in a myeloid differentiation protein 88-dependent manner. Our results provide support for the therapeutic potential of xanthoceraside in AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / drug therapy*
  • Alzheimer Disease / genetics
  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Anti-Inflammatory Agents*
  • Cells, Cultured
  • Depression, Chemical
  • Dose-Response Relationship, Drug
  • Interferon-gamma / pharmacology*
  • Interleukin-1beta / metabolism*
  • Mice
  • Microglia
  • Mitogen-Activated Protein Kinases / physiology*
  • Molecular Targeted Therapy
  • Myeloid Differentiation Factor 88 / physiology*
  • NF-kappa B / metabolism
  • NF-kappa B / physiology*
  • Neuroprotective Agents*
  • Peptide Fragments / pharmacology*
  • Saponins / pharmacology*
  • Saponins / therapeutic use
  • Signal Transduction / genetics*
  • Signal Transduction / physiology*
  • Toll-Like Receptor 2 / physiology*
  • Triterpenes / pharmacology*
  • Triterpenes / therapeutic use
  • Tumor Necrosis Factor-alpha / metabolism*

Substances

  • Amyloid beta-Peptides
  • Anti-Inflammatory Agents
  • Interleukin-1beta
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • NF-kappa B
  • Neuroprotective Agents
  • Peptide Fragments
  • Saponins
  • Tlr2 protein, mouse
  • Toll-Like Receptor 2
  • Triterpenes
  • Tumor Necrosis Factor-alpha
  • amyloid beta-protein (25-35)
  • xanthoceraside
  • Interferon-gamma
  • Mitogen-Activated Protein Kinases