Neutrophil elastase stimulates human airway epithelial cells to produce PGE2 through activation of p44/42 MAPK and upregulation of cyclooxygenase-2.
The responses of airway epithelium following exposure to neutrophil elastase (NE) were investigated. Human bronchial epithelial cells were explanted on insert surfaces of a modified air-liquid interface culture system to which NE was added to stimulate epithelial cells. PGE2 release significantly increased within 10 min of incubation with NE and peaked 3 h after NE (20 microg/ml) stimulation. This action required proteolytic activity as alpha1-antitrypsin blocked NE-induced PGE2 release. The production of PGE2 was also inhibited by indomethacin; a selective cyclooxygenase (COX)-2 inhibitor, celecoxib; and dexamethasone. Moreover, the mRNA expression for COX-2 relative to that for a housekeeping gene was approximately eightfold that of the unstimulated cells. Dexamethasone inhibited COX-2 gene transcription. We further observed that NE-induced PGE2 release involved activation of p44/42, but not p38, MAP kinases. Such p44/42 MAP kinases were rapidly phosphorylated, with the concentration of phosphorylated p44/42 MAP kinases peaking at 10 min after stimulation and declining in culture at 90 min. The specific p44/42 MAP kinase inhibitor UO126 completely blocked p44/42 phosphorylation and, subsequently, PGE2 production. The airway epithelium may play important bronchoprotective and immunomodulatory roles in chronic neutrophilic inflammation.
Perng
Diahn-Warng
DW
Dept. of Chest Medicine, Taipei Veterans General Hospital, 201, Section 2, Shih-Pai Rd., Taipei 11217, Taiwan. dwperng@vghtpe.gov.tw
Wu
Yu-Chung
YC
Tsai
Mei-Chuan
MC
Lin
Ching-Ping
CP
Hsu
Wen-Hu
WH
Perng
Reury-Perng
RP
Lee
Yu-Chin
YC
D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002070:Butadienes / Q000494:pharmacology; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis* / Q000378:metabolism; D004789:Enzyme Activation / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D019272:Leukocyte Elastase / Q000494:pharmacology*; D008565:Membrane Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation
D002070:Butadienes; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D009570:Nitriles; D012333:RNA, Messenger; C113580:U 0126; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D019272:Leukocyte Elastase; D015232:Dinoprostone