Contribution of cyclooxygenase-1 and cyclooxygenase-2 to prostanoid formation by human enterocytes stimulated by calcium ionophore and inflammatory agents.
The stimulation of intestinal epithelial cell cyclooxygenase (COX) enzymes with inflammatory agents and the inhibition of COX-1 and COX-2 enzymes has the potential to increase understanding of the role of these enzymes in intestinal inflammation. The aim of this study was to determine the contributions of COX-1 and -2 to the production of specific prostanoids by unstimulated and stimulated intestinal epithelial cells. Cultured enterocytes were stimulated with lipopolysaccharide (LPS), interleukin-1 (IL-1)beta (IL-1 beta), and calcium ionophore (Ca Ion), with and without COX inhibitors. Valerylsalicylic acid (VSA) was employed as the COX-1 inhibitor, and SC-58125 and NS398 were used as the COX-2 inhibitors. Prostanoids were quantitated by Elisa assay. Western immunoblotting demonstrated the presence of constitutive COX-1 and inducible COX-2 enzyme. Unstimulated prostanoid formation was not decreased by the COX-1 inhibitor. All of the stimulants evaluated increased prostaglandin E2 (PGE2) production. Only Ca Ion stimulated prostaglandin D2 (PGD2) production while IL-1 beta, and Ca Ion, but not LPS, increased prostaglandin F2 alpha (PGF2 alpha) formation. Ca Ion-stimulated prostanoid formation was uniformly inhibited by COX-2, but not COX-1, inhibitors. IL-1 beta-stimulated PGE2 and PGE2 alpha formation was significantly decreased by both COX-1 and COX-2 inhibitors. VSA, in a dose-dependent manner, significantly decreased IL-1 beta-stimulated PGE2 and PGF2 alpha production. Unstimulated prostanoid formation was not dependent on constitutive COX-1 activity. The stimulation of intestinal epithelial cells by Ca Ion seemed to uniformly produce prostanoids through COX-2 activity. There was no uniform COX-1 or COX-2 pathway for PGE and PGF2 alpha formation stimulated by the inflammatory agents, suggesting that employing either a COX-1 or COX-2 inhibitor therapeutically will have varying effects on intestinal epithelial cells dependent on the prostanoid species and the inflammatory stimulus involved.
Longo
W E
WE
Department of Surgery, Theodore Cooper Surgical Research Institute, Saint Louis University School of Medicine and Health Sciences Center, Missouri, USA.
Panesar
N
N
Mazuski
J
J
Kaminski
D L
DL
D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000737:chemistry*; D002460:Cell Line; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D015777:Eicosanoids / Q000032:analysis; D004847:Epithelial Cells / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D007375:Interleukin-1 / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007527:Isoenzymes / Q000494:pharmacology / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins; D009578:Nitrobenzenes / Q000494:pharmacology; D015230:Prostaglandin D2 / Q000096:biosynthesis; D011451:Prostaglandin-Endoperoxide Synthases / Q000494:pharmacology / Q000502:physiology*; D011453:Prostaglandins / Q000096:biosynthesis*; D011720:Pyrazoles / Q000494:pharmacology; D012459:Salicylates / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology