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alpha-MSH inhibits TNF-alpha-induced matrix metalloproteinase-13 expression by modulating p38 kinase and nuclear

S W Yoon1, J S Chun, M H Sung

  • 1Bionanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon, Republic of Korea.

Osteoarthritis and Cartilage
|August 9, 2007
PubMed
Abstract

Insights

Alpha-melanocyte-stimulating hormone (alpha-MSH) inhibits tumor necrosis factor-alpha (TNF-alpha)-induced matrix metalloproteinase-13 (MMP-13) expression in human chondrocytes. This suggests alpha-MSH could be a potential therapeutic for arthritis by reducing collagen degradation.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Immunology

Background:

  • Matrix metalloproteinases (MMPs) contribute to cartilage destruction in arthritis.
  • Alpha-melanocyte-stimulating hormone (alpha-MSH) is present in synovial fluid and may have anti-inflammatory effects.
  • Understanding the signaling pathways of alpha-MSH in chondrocytes is crucial for developing arthritis therapeutics.

Purpose of the Study:

  • To investigate if alpha-MSH downregulates pro-inflammatory cytokine-induced MMP expression.
  • To elucidate the intracellular signaling pathways involved in alpha-MSH's effect on MMP expression.
  • To assess the potential of alpha-MSH as an anti-arthritis therapeutic agent.

Main Methods:

  • Human chondrosarcoma cells (HTB-94) were treated with alpha-MSH and tumor necrosis factor-alpha (TNF-alpha).
  • Reverse transcriptase-polymerase chain reaction and Western blot analysis were used to measure MMP-13 expression and mitogen-activated protein kinases (MAPKs) activation.
  • Inhibitors of MAPKs, nuclear factor kappaB (NF-kappaB), and dominant-negative plasmids were used to investigate intracellular signaling.

Main Results:

  • Alpha-MSH pretreatment inhibited TNF-alpha-induced MMP-13 expression and p38 kinase phosphorylation.
  • Extracellular signal-regulated kinase (ERK) and c-jun terminal kinase (JNK) inhibitors did not affect MMP-13 expression.
  • Inhibitors of p38 kinase, NF-kappaB, and dominant-negative IKKalpha/beta suppressed TNF-alpha-induced MMP-13 expression.

Conclusions:

  • Alpha-MSH regulates TNF-alpha-induced MMP-13 expression by reducing p38 kinase phosphorylation and subsequent NF-kappaB activation in human chondrocytes.
  • Alpha-MSH shows potential as an inhibitor of MMP-13-mediated collagen degradation.
  • These findings offer new therapeutic strategies for arthritis treatment.

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