title: Regulation of cyclooxygenase-2 expression by phosphatidate phosphohydrolase in human amnionic WISH cells.
abstract: Prostaglandins are known to play a key role in the initiation of labor in humans, but the mechanisms governing their synthesis in amnion are largely unknown. In this study, we have examined the regulatory pathways for prostaglandin E(2) (PGE(2)) production during protein kinase C-dependent activation of human WISH cells. In these cells, PGE(2) synthesis appears to be limited not by free arachidonic acid availability but by the expression levels of cyclooxygenase-2 (COX-2). Concomitant with the cells being able to synthesize and secrete PGE(2), we detected significant elevations of both COX-2 protein and mRNA levels. Specific inhibition of COX-2 by NS-398 totally ablated PGE(2) synthesis. All of these responses were found to be strikingly dependent on an active phosphatidate phosphohydrolase 1 (PAP-1). Inhibition of PAP-1 activity by three different strategies (i.e. use of bromoenol lactone, propranolol, and ethanol) resulted in inhibition of COX-2 expression and hence of PGE(2) production. These data unveil a novel signaling mechanism for the regulation of PGE(2) production via regulation of COX-2 expression and implicate phosphatidate phosphohydrolase 1 as a key regulatory component of eicosanoid metabolic pathways in the amnion.
authors.affiliation: Department of Chemistry and Biochemistry, Revelle College and School of Medicine, University of California at San Diego, La Jolla, California 92093-0601, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Johnson
authors.forename: M A
authors.initials: MA
authors.lastname: Balboa
authors.forename: J
authors.initials: J
authors.lastname: Balsinde
authors.forename: E A
authors.initials: EA
authors.lastname: Dennis
mesh_terms: D000650:Amnion / Q000166:cytology; D016718:Arachidonic Acid / Q000378:metabolism; D002460:Cell Line; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins; D009281:Naphthalenes / Q000494:pharmacology; D009578:Nitrobenzenes / Q000494:pharmacology; D000073718:Pancreatitis-Associated Proteins; D010711:Phosphatidate Phosphatase / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics* / Q000378:metabolism*; D011753:Pyrones / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D009281:Naphthalenes; D009578:Nitrobenzenes; D000073718:Pancreatitis-Associated Proteins; D010726:Phosphodiesterase Inhibitors; D011753:Pyrones; C000612141:REG3A protein, human; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D016718:Arachidonic Acid; D000431:Ethanol; C068314:6-(bromomethylene)tetrahydro-3-(1-naphthaleneyl)-2H-pyran-2-one; D011433:Propranolol; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010711:Phosphatidate Phosphatase; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate