Interleukin-1 beta induces prostaglandin G/H synthase-2 (cyclooxygenase-2) in primary murine astrocyte cultures.
Activation of glial cells and the consequent release of cytokines, proteins, and other intercellular signaling molecules is a well-recognized phenomenon in brain injury and neurodegenerative disease. We and others have previously described an inducible prostaglandin G/H synthase, known as PGHS-2 or cyclooxygenase-2, that is up-regulated in many cell systems by cytokines and growth factors and down-regulated by glucocorticoid hormones. In cultured mouse astrocytes we observed increased production of prostaglandin E2 (PGE2) after stimulation with either interleukin-1 beta (IL-1 beta) or the protein kinase C activator phorbol 12-myristate 13-acetate (TPA). This increase in PGE2 content was blocked by pretreatment with dexamethasone and correlated with increases in cyclooxygenase activity measured at 4 h. Northern blots revealed concomitant increases in PGHS-2 mRNA levels that peaked at 2 h and were dependent on the dosage of IL-1 beta. Dexamethasone inhibited this induction of PGHS-2 mRNA by IL-1 beta. TPA, basic fibroblast growth factor, and the proinflammatory factors tumor necrosis factor alpha and lipopolysaccharide, but not interleukin-6, also stimulated PGHS-2 mRNA expression. Relative to IL-1 beta, the greater increases in PGE2 production and cyclooxygenase activity caused by TPA correlated with a greater induction of PGHS-2 mRNA. Furthermore NS-398, a specific inhibitor of cyclooxygenase-2, blocked > 80% of the cyclooxygenase activity in TPA-treated astrocytes. These findings indicate that increased expression of PGHS-2 contributes to prostaglandin production in cultured astrocytes exposed to cytokines and other factors.
O'Banion
M K
MK
Department of Neurology, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
Miller
J C
JC
Chang
J W
JW
Kaplan
M D
MD
Coleman
P D
PD
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000201:enzymology*; D002478:Cells, Cultured / Q000187:drug effects / Q000201:enzymology; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004790:Enzyme Induction; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D007527:Isoenzymes / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D009578:Nitrobenzenes / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D013449:Sulfonamides / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007375:Interleukin-1; D007527:Isoenzymes; D008070:Lipopolysaccharides; D009578:Nitrobenzenes; D010703:Phorbol Esters; D012333:RNA, Messenger; D013449:Sulfonamides; D014409:Tumor Necrosis Factor-alpha; D016222:Fibroblast Growth Factor 2; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D003907:Dexamethasone; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D013755:Tetradecanoylphorbol Acetate