title: ERK1/2 mediates TNF-alpha-induced matrix metalloproteinase-9 expression in human vascular smooth muscle cells via the regulation of NF-kappaB and AP-1: Involvement of the ras dependent pathway.
abstract: The expression of matrix metalloproteinase-9 (MMP-9) has been implicated in progression of atherosclerotic lesions. The role and importance of the signaling pathway in the transcriptional regulation of MMP-9 in human aortic smooth muscle cells (HASMC) was examined. Tumor necrosis factor-alpha (TNF-alpha) stimulated the secretion of MMP-9 in HASMC, as shown by zymography and immunoblot analysis. At the transcriptional levels, TNF-alpha also stimulated the 5'-flanking 710-bp promoter activity of MMP-9. Transcription factors NF-kappaB binding site (-601) and AP-1 binding site (-82) were identified as the cis-elements for TNF-alpha activation, as determined by gel shift assay and mutation analysis. Treatment with U0126, an inhibitor of the extracellular signal-regulated kinase (ERK), significantly downregulated TNF-alpha-induced MMP-9 expression and promoter activity, whereas the inactive analog U0124 had no effect. Furthermore, the transactivation of TNF-alpha-stimulated NF-kappaB and AP-1 was inhibited by U0126 treatment. Finally, the transient transfection of HASMC with dominant negative Ras (RasN17) suppressed TNF-alpha-induced ERK activity, MMP-9 production, and promoter activity. Overexpression of RasN17 also abolished the TNF-alpha-stimulated NF-kappaB and AP-1 activity. In conclusion, the findings herein indicate the activation of the Ras/ERK pathway contributes to the induction of MMP-9 expression in HASMC. In addition, the transcription factors NF-kappaB and AP-1 that are involved in the Ras/ERK-mediated control of MMP-9 regulation on HASMC in response to TNF-alpha have now been identified.
authors.affiliation: National Research Laboratory for Glycobiology, Korean Ministry of Science and Technology, Kyungju, Kyungbuk, Korea.
authors.forename: Sung-Kwon
authors.initials: SK
authors.lastname: Moon
authors.forename: Byung-Yoon
authors.initials: BY
authors.lastname: Cha
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
mesh_terms: D002478:Cells, Cultured; D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D004791:Enzyme Inhibitors; D011905:Genes, ras / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000502:physiology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020780:Matrix Metalloproteinase 9