title: Matrix metalloprotease-9 induces transforming growth factor-β(1) production in airway epithelium via activation of epidermal growth factor receptors.
abstract: OBJECTIVE
  Matrix metalloprotease (MMP)-9 is present in abundance in various chronic airway disorders and is involved in lung remodeling. MMP may cleave membrane-bound precursor proteins and release epidermal growth factor-like ligands that subsequently bind to epidermal growth factor receptor (EGFR). We hypothesized that MMP-9 may stimulate the airway epithelium to produce fibrogenic mediators through activation of membrane-bound receptors.
  
  
  METHODS
  Human airway epithelial cells were grown on air-liquid interface culture inserts. MMP-9 was employed to stimulate the cells. Conditioned medium following MMP-9 stimulation was co-incubated with human lung fibroblasts.
  
  
  RESULTS
  MMP-9 stimulated human airway epithelial cells to produce transforming growth factor (TGF)-β(1) at both the mRNA and protein level. Using a microarray, increased phosphorylation of EGFR tyrosine kinase (TK) was identified and further confirmed by immunoprecipitation and Western blot analysis. A significant increase in EGF and TGF-α release was observed after MMP-9 had been added for 30min. Protease inhibitor, EGFR monoclonal antibody and EGFR-TK inhibitor blocked this action and subsequent TGF-β(1) production. Neutralizing antibodies against EGF and TGF-α substantially inhibited TGF-β(1) production following MMP-9 stimulation. MMP-9-induced TGF-β(1) production occurred through MAP kinase p44/42 phosphorylation. Selective p44/42 kinase inhibitor UO126 successfully inhibited TGF-β(1) production. Conditioned medium from epithelial cells treated with MMP-9 significantly induced Smad3 phosphorylation and subsequent fibroblast proliferation after 24h culture.
  
  
  CONCLUSIONS
  These data indicate that MMP-9 induces TGF-β(1) production in the airway epithelium through the cleavage of EGF and EGF-like ligands and activating EGFR, suggesting potential targets of therapeutic intervention in airway fibrotic disorders.
authors: Department of Chest Medicine, Taipei Veterans General Hospital, Taiwan. dwperng@vghtpe.gov.tw
authors: Diahn-Warng
authors: DW
authors: Perng
authors: Kuo-Ting
authors: KT
authors: Chang
authors: Kang-Cheng
authors: KC
authors: Su
authors: Yu-Chung
authors: YC
authors: Wu
authors: Chun-Sheng
authors: CS
authors: Chen
authors: Wen-Hu
authors: WH
authors: Hsu
authors: Chun-Ming
authors: CM
authors: Tsai
authors: Yu-Chin
authors: YC
authors: Lee
mesh_terms: D000402:Airway Obstruction / Q000201:enzymology / Q000503:physiopathology; D015153:Blotting, Western; D049109:Cell Proliferation; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000819:agonists* / Q000378:metabolism; D005347:Fibroblasts; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051900:Smad3 Protein / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000096:biosynthesis*
chemical_list: D012333:RNA, Messenger; C497790:SMAD3 protein, human; D051900:Smad3 Protein; D016211:Transforming Growth Factor alpha; D053773:Transforming Growth Factor beta1; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D020794:Receptor Protein-Tyrosine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D020780:Matrix Metalloproteinase 9