title: Tumor necrosis factor-alpha augments matrix metalloproteinase-9 production in skeletal muscle cells through the activation of transforming growth factor-beta-activated kinase 1 (TAK1)-dependent signaling pathway.
abstract: We have investigated the effect of tumor necrosis factor-alpha (TNF-alpha) on the production of extracellular matrix-degrading proteases in skeletal muscles. Using microarray, quantitative PCR, Western blotting, and zymography, we found that TNF-alpha drastically increases the production of matrix metalloproteinase (MMP)-9 from C2C12 myotubes. In vivo administration of TNF-alpha in mice increased the transcript level of MMP-9 in skeletal muscle tissues. Although TNF-alpha activated all the three MAPKs (i.e. ERK1/2, JNK, and p38), inhibition of ERK1/2 or p38 but not JNK blunted the TNF-alpha-induced production of MMP-9 from myotubes. Inhibition of Akt also inhibited the TNF-alpha-induced production of MMP-9. TNF-alpha increased the activation of transcription factors NF-kappaB and AP-1 but not SP-1 in myotubes. Overexpression of a dominant negative inhibitor of NF-kappaB or AP-1 blocked the TNF-alpha-induced expression of MMP-9 in myotubes. Similarly, point mutations in AP-1- or NF-kappaB-binding sites in MMP-9 promoter inhibited the TNF-alpha-induced expression of a reporter gene. TNF-alpha increased the activity of transforming growth factor-beta-activating kinase-1 (TAK1). Furthermore, overexpression of a dominant negative mutant of TAK1 blocked the TNF-alpha-induced expression of MMP-9 and activation of NF-kappaB and AP-1. Our results also suggest that TNF-alpha induces MMP-9 expression in muscle cells through the recruitment of TRAF-2, Fas-associated protein with death domain, and TNF receptor-associated protein with death domain but not NIK or TRAF-6 proteins. We conclude that TAK1-mediated pathways are involved in TNF-alpha-induced MMP-9 production in skeletal muscle cells.
authors: Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, California 92357, USA.
authors: Apurva K
authors: AK
authors: Srivastava
authors: Xuezhong
authors: X
authors: Qin
authors: Nia
authors: N
authors: Wedhas
authors: Marc
authors: M
authors: Arnush
authors: Thomas A
authors: TA
authors: Linkhart
authors: Robert B
authors: RB
authors: Chadwick
authors: Ashok
authors: A
authors: Kumar
mesh_terms: D000818:Animals; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D015398:Signal Transduction; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D020930:MAP Kinase Kinase Kinases; D020780:Matrix Metalloproteinase 9; D014409:Tumor Necrosis Factor-alpha; D000099151:MAP Kinase Kinase Kinase 7