alpha-MSH inhibits TNF-alpha-induced matrix metalloproteinase-13 expression by modulating p38 kinase and nuclear factor kappaB signaling in human chondrosarcoma HTB-94 cells.
OBJECTIVE
Proinflammatory cytokine-induced expression of matrix metalloproteinases (MMPs) is a major cause of arthritic cartilage destruction. The neuropeptide, alpha-melanocyte-stimulating hormone (alpha-MSH), has been detected in the synovial fluid of arthritis patients, where it is thought to play an anti-inflammatory role. Here, we examined whether alpha-MSH acts via downregulation of MMP expression, and sought to elucidate the intracellular signal pathways underlying this effect.


METHODS
Human chondrosarcoma cell line, HTB-94 (SW1353) was pretreated with or without alpha-MSH and then treated with tumor necrosis factor-alpha (TNF-alpha). The effect of alpha-MSH on TNF-alpha-induced MMP-13 expression and mitogen-activated protein kinases' (MAPKs) activation were determined by reverse transcriptase-polymerase chain reaction and Western blot analysis. Additionally, the intracellular signaling of alpha-MSH was investigated using the inhibitors of MAPK and nuclear factor kappaB (NF-kappaB) and plasmids encoding dominant negative (dn) forms of inhibitor kappaB kinase-alpha (IKKalpha) and inhibitor kappaB kinase-beta (IKKbeta).


RESULTS
We found that alpha-MSH pretreatment inhibited TNF-alpha-induced MMP-13 expression and p38 kinase phosphorylation in HTB-94 human chondrosarcoma cells. TNF-alpha-induced MMP-13 expression was not suppressed by extracellular signal-regulated kinase (ERK) inhibitors (PD98059 and U0126) or a c-jun terminal kinase (JNK) inhibitor (SP600125), but was inhibited by inhibitors of p38 kinase (SB203580) and NF-kappaB (SN-50 peptide) and dnIKKalpha and dnIKKbeta.


CONCLUSIONS
Our results suggest that alpha-MSH regulates TNF-alpha-induced MMP-13 expression by decreasing p38 kinase phosphorylation and subsequent NF-kappaB activation in human chondrocytes and may be an effective inhibitor of MMP-13-mediated collagen degradation, providing new potential opportunities for the development of anti-arthritis therapeutics.
Yoon
S W
SW
Bionanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon, Republic of Korea.
Chun
J S
JS
Sung
M H
MH
Kim
J Y
JY
Poo
H
H
D015153:Blotting, Western; D002450:Cell Communication; D045744:Cell Line, Tumor; D002813:Chondrosarcoma / Q000201:enzymology* / Q000276:immunology; D005260:Female; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism*; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D000521:alpha-MSH / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D006728:Hormones; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D000521:alpha-MSH; D048051:p38 Mitogen-Activated Protein Kinases; D053509:Matrix Metalloproteinase 13