title: Tumor necrosis factor-alpha induces MMP-9 expression via p42/p44 MAPK, JNK, and nuclear factor-kappaB in A549 cells.
abstract: Matrix metalloproteinases (MMPs), in particular MMP-9, have been shown to be induced by cytokines including tumor necrosis factor-alpha (TNF-alpha) and contributes to airway inflammation. However, the mechanisms underlying MMP-9 expression induced by TNF-alpha in human A549 cells remain unclear. Here, we showed that TNF-alpha induced production of MMP-9 protein and mRNA is determined by zymographic, Western blotting, RT-PCR and ELISA assay, which were attenuated by inhibitors of MEK1/2 (U0126), JNK (SP600125), and NF-kappaB (helenalin), and transfection with dominant negative mutants of ERK2 (DeltaERK) and JNK (DeltaJNK), and siRNAs for MEK1, p42 and JNK2. TNF-alpha-stimulated phosphorylation of p42/p44 MAPK and JNK were attenuated by pretreatment with the inhibitors U0126 and SP600125 or transfection with dominant negative mutants of DeltaERK and DeltaJNK. Furthermore, the involvement of NF-kappaB in TNF-alpha-induced MMP-9 production was consistent with that TNF-alpha-stimulated degradation of IkappaB-alpha and translocation of NF-kappaB into the nucleus which were blocked by helenalin, but not by U0126 and SP600125, revealed by immunofluorescence staining. The regulation of MMP-9 gene transcription by MAPKs and NF-kappaB was further confirmed by gene luciferase activity assay. MMP-9 promoter activity was enhanced by TNF-alpha in A549 cells transfected with wild-type MMP-9-Luc, which was inhibited by helenalin, U0126, or SP600125. In contrast, TNF-alpha-stimulated MMP-9 luciferase activity was totally lost in cells transfected with mutant-NF-kappaB MMP-9-luc. Moreover, pretreatment with actinomycin D and cycloheximide attenuated TNF-alpha-induced MMP-9 expression. These results suggest that in A549 cells, phosphorylation of p42/p44 MAPK, JNK, and transactivation of NF-kappaB are essential for TNF-alpha-induced MMP-9 gene expression.
authors.affiliation: Department of Anesthetics, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Hsiao-Wei
authors.initials: HW
authors.lastname: Tseng
authors.forename: Hsi-Lung
authors.initials: HL
authors.lastname: Hsieh
authors.forename: Chiang-Wen
authors.initials: CW
authors.lastname: Lee
authors.forename: Cheng-Ying
authors.initials: CY
authors.lastname: Wu
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Cheng
authors.forename: Chuen-Mao
authors.initials: CM
authors.lastname: Yang
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D008156:Luciferases / Q000187:drug effects / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000187:drug effects* / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D008156:Luciferases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020780:Matrix Metalloproteinase 9