Cyclooxygenase-2 and synthesis of PGE2 in human bronchial smooth-muscle cells.

T Vigano, A Habib, A Hernandez, A Bonazzi… - American journal of …, 1997 - atsjournals.org
T Vigano, A Habib, A Hernandez, A Bonazzi, D Boraschi, M Lebret, E Cassina, J Maclouf…
American journal of respiratory and critical care medicine, 1997atsjournals.org
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 …
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.
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