Oleoylethanolamide exerts anti-inflammatory effects on LPS-induced THP-1 cells by enhancing PPARα signaling and inhibiting the NF-κB and ERK1/2/AP-1/STAT3 pathways

Sci Rep. 2016 Oct 10:6:34611. doi: 10.1038/srep34611.

Abstract

The present study aimed to examine the anti-inflammatory actions of oleoylethanolamide (OEA) in lipopolysaccharide (LPS)-induced THP-1 cells. The cells were stimulated with LPS (1 μg/ml) in the presence or absence of OEA (10, 20 and 40 μM). The pro-inflammatory cytokines were evaluated by qRT-PCR and ELISA. The THP-1 cells were transiently transfected with PPARα small-interfering RNA, and TLR4 activity was determined with a blocking test using anti-TLR4 antibody. Additionally, a special inhibitor was used to analyse the intracellular signaling pathway. OEA exerted a potent anti-inflammatory effect by reducing the production of pro-inflammatory cytokines and TLR4 expression, and by enhancing PPARα expression. The modulatory effects of OEA on LPS-induced inflammation depended on PPARα and TLR4. Importantly, OEA inhibited LPS-induced NF-κB activation, IκBα degradation, expression of AP-1, and the phosphorylation of ERK1/2 and STAT3. In summary, our results demonstrated that OEA exerts anti-inflammatory effects by enhancing PPARα signaling, inhibiting the TLR4-mediated NF-κB signaling pathway, and interfering with the ERK1/2-dependent signaling cascade (TLR4/ERK1/2/AP-1/STAT3), which suggests that OEA may be a therapeutic agent for inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Humans
  • Inflammation / chemically induced
  • Inflammation / metabolism
  • Inflammation / pathology
  • Lipopolysaccharides / toxicity*
  • MAP Kinase Signaling System / drug effects*
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / metabolism*
  • NF-kappa B / metabolism*
  • Oleic Acids / pharmacology*
  • PPAR alpha / metabolism*
  • STAT3 Transcription Factor / metabolism*
  • THP-1 Cells
  • Transcription Factor AP-1 / metabolism*

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Lipopolysaccharides
  • NF-kappa B
  • Oleic Acids
  • Oleylethanolamide
  • PPAR alpha
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Transcription Factor AP-1
  • MAPK1 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3