Toll-like receptor 4/nuclear factor-κB signaling pathway is involved in ACTG-toxin H-mediated anti-inflammatory effect

Mol Cell Biochem. 2013 Feb;374(1-2):29-36. doi: 10.1007/s11010-012-1502-9. Epub 2012 Nov 9.

Abstract

ACTG-toxin H (AH) originates from Alternaria sp. In this study, we explored the molecular mechanism underlying the anti-inflammatory properties of AH. Treatment with AH inhibited lipopolysaccharide (LPS)-induced interleukin-6, IL-1β, inducible nitric oxide synthase, and cyclooxygenase-2 expression and nitric oxide production. Furthermore, AH inhibited LPS-induced P38 MAPK and Akt activation in RAW264.7 cells. Electrophoretic mobility shift assays (EMSAs) showed that AH inhibited LPS-induced nuclear factor-κB (NFκB) DNA-binding activity. Using transfection assay and measurement of an NFκB-sensitive promoter region, we found that transfection of toll-like receptor 4 (TLR4) increased LPS-induced NFκB transcription activity in 293T cells. AH significantly blocked LPS-induced NFκB activation in TLR4-transfected cells. Taken together, our data indicated that anti-inflammatory properties of AH resulted from the inhibition of proinflammatory cytokines and enzyme production via the TLR4/NFκB signaling pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternaria / metabolism
  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Line
  • Cell Survival
  • Cyclooxygenase 2 / metabolism
  • DNA-Binding Proteins / metabolism
  • Enzyme Activation / drug effects
  • HEK293 Cells
  • Humans
  • Inflammation / immunology*
  • Interleukin-1beta / metabolism
  • Interleukin-6 / metabolism
  • Lipopolysaccharides
  • Macrophages / metabolism
  • Mice
  • Mycotoxins / pharmacology*
  • NF-kappa B / metabolism*
  • Nitric Oxide / biosynthesis
  • Nitric Oxide Synthase Type II / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Anti-Inflammatory Agents
  • DNA-Binding Proteins
  • Interleukin-1beta
  • Interleukin-6
  • Lipopolysaccharides
  • Mycotoxins
  • NF-kappa B
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Nitric Oxide
  • Nitric Oxide Synthase Type II
  • Cyclooxygenase 2
  • Proto-Oncogene Proteins c-akt
  • p38 Mitogen-Activated Protein Kinases