Cyclooxygenase-2 and synthesis of PGE2 in human bronchial smooth-muscle cells.
The purpose of this study was to determine the mechanism of enhanced prostaglandin synthesis in cultured human bronchial smooth-muscle cells challenged with interleukin-1 beta (IL-1 beta). Cells were incubated with IL-1 beta (10 to 50 U/ml) for 0 to 24 h. Prostaglandin E2 (PGE2) production was evaluated through the conversion of exogenous (14C)-arachidonic acid and specific enzyme immunoassay of endogenous products. IL-1 beta enhanced PGE2 formation in a concentration- and time-dependent manner, reaching its peak at 6 to 8 h and fading at 18 to 24 h. Immunoblot analysis showed that the inducible cyclooxygenase enzyme (COX-2) was expressed only in IL-1 beta treated cells, whereas the constitutive isoform of cyclooxygenase (COX-1) remained unaltered. COX-2 expression and PGE2 formation were inhibited by dexamethasone (2 microM), cycloheximide (10 microM), and IL-1-receptor antagonist (IL-1 ra) (250 ng/ml), independently. PGE2 synthesis was significantly reduced by compound SC-58125, a specific COX-2 inhibitor. The close parallelism between the kinetics of COX-2 protein expression and PGE2 accumulation, as well as the constitutive nature of COX-1 isoform, indicate that IL-1 beta-driven PGE2 formation in human bronchial smooth-muscle cells is mediated by de novo expression of COX-2 enzyme.
Viganò
T
T
Institute of Pharmacological Sciences, School of Pharmacy, University of Milan, Italy.
Habib
A
A
Hernandez
A
A
Bonazzi
A
A
Boraschi
D
D
Lebret
M
M
Cassina
E
E
Maclouf
J
J
Sala
A
A
Folco
G
G
D016718:Arachidonic Acid / Q000494:pharmacology; D015153:Blotting, Western; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015151:Immunoblotting; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis*; D008565:Membrane Proteins; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011720:Pyrazoles / Q000494:pharmacology; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D012795:Sialoglycoproteins / Q000494:pharmacology
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D011720:Pyrazoles; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins; C090859:1-((4-methylsulfonyl)phenyl)-3-trifluoromethyl-5-(4-fluorophenyl)pyrazole; D016718:Arachidonic Acid; D003907:Dexamethasone; D003513:Cycloheximide; D010544:Peroxidases; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone