Induction of cyclooxygenase-2 by lipopolysaccharide in canine tracheal smooth muscle cells: involvement of p42/p44 and p38 mitogen-activated protein kinases and nuclear factor-kappaB pathways.
Lipopolysaccharide (LPS) was found to induce inflammatory responses in the airways and exerted as a potent stimulus for PG synthesis. This study was to determine the mechanisms of LPS-enhanced cyclooxygenase (COX)-2 expression associated with PGE(2) synthesis in tracheal smooth muscle cells (TSMCs). LPS markedly increased the expression of COX-2 and release of PGE(2) in a time- and concentration-dependent manner, whereas COX-1 remained unaltered. Both the expression of COX-2 and the generation of PGE(2) in response to LPS were attenuated by a tyrosine kinase inhibitor genistein, a phosphatidylcholine-phospholipase C inhibitor D609, a phosphatidylinositol-phospholipase C inhibitor U73122, protein kinase C inhibitors, GF109203X and staurosporine, removal of Ca(2+) by addition of BAPTA/AM plus EGTA, and phosphatidylinositol 3-kinase (PI3-K) inhibitors, LY294002 and wortmannin. Furthermore, LPS-induced NF-kappaB activation correlated with the degradation of IkappaB-alpha, COX-2 expression, and PGE(2) synthesis, was inhibited by transfection with dominant negative mutants of NIK and IKK-alpha, but not by IKK-beta. LPS-induced COX-2 expression and PGE(2) synthesis were completely inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK inhibitor), but these two inhibitors had no effect on LPS-induced NF-kappaB activation, indicating that NF-kappaB is activated by LPS independently of activation of p42/p44 MAPK and p38 MAPK pathways in TSMCs. Taken together, these findings suggest that the increased expression of COX-2 correlates with the release of PGE(2) from LPS-challenged TSMCs, at least in part, independently mediated through MAPKs and NF-kappaB signalling pathways. LPS-mediated responses were modulated by PLC, Ca(2+), PKC, tyrosine kinase, and PI3-K in these cells.
Luo
Shue-Fen
SF
Department of Internal Medicine, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
Wang
Chuan-Chwan
CC
Chien
Chin-Sung
CS
Hsiao
Li-Der
LD
Yang
Chuen-Mao
CM
D000818:Animals; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007527:Isoenzymes / Q000096:biosynthesis* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology*; D016328:NF-kappa B / Q000502:physiology*; D037342:Pertussis Toxin / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D014132:Trachea / Q000166:cytology; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008070:Lipopolysaccharides; D016328:NF-kappa B; D000081082:Phosphoinositide-3 Kinase Inhibitors; D005576:Colforsin; D002772:Cholera Toxin; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015232:Dinoprostone; D002118:Calcium