Up-regulation of prostaglandin E2 synthesis by interleukin-1beta in human orbital fibroblasts involves coordinate induction of prostaglandin-endoperoxide H synthase-2 and glutathione-dependent prostaglandin E2 synthase expression.
Prostaglandin E(2) (PGE(2)) production involves the activity of a multistep biosynthetic pathway. The terminal components of this cascade, two PGE(2) synthases (PGES), have very recently been identified as glutathione-dependent proteins. cPGES is cytoplasmic, apparently identical to the hsp90 chaperone, p23, and associates functionally with prostaglandin-endoperoxide H synthase-1 (PGHS-1), the constitutive cyclooxygenase. A second synthase, designated mPGES, is microsomal and can be regulated. Here we demonstrate that mPGES and PGHS-2 are expressed at very low levels in untreated human orbital fibroblasts. Interleukin (IL)-1beta treatment elicits high levels of PGHS-2 and mPGES expression. The induction of both enzymes occurs at the pretranslational level, is the consequence of enhanced gene promoter activities, and can be blocked by dexamethasone (10 nm). SC58125, a PGHS-2-selective inhibitor, could attenuate the induction of mPGES, suggesting a dependence of this enzyme on PGHS-2 activity. IL-1beta treatment activates p38 and ERK mitogen-activated protein kinases. Induction of both mPGES and PGHS-2 was susceptible to either chemical inhibition or molecular interruption of these pathways with dominant negative constructs. These results indicate that the induction of PGHS-2 and mPGES by IL-1beta underlies robust PGE(2) production in orbital fibroblasts.
Han
Rui
R
Division of Molecular Medicine, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90502, USA.
Tsui
Shanli
S
Smith
Terry J
TJ
D015152:Blotting, Northern; D015153:Blotting, Western; D023201:CD40 Ligand / Q000096:biosynthesis; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism*; D005938:Glucocorticoids / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D000071876:Prostaglandin-E Synthases; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011720:Pyrazoles / Q000494:pharmacology; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases
D016861:Cyclooxygenase Inhibitors; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D005938:Glucocorticoids; D007375:Interleukin-1; D020033:Protein Isoforms; D011720:Pyrazoles; D012333:RNA, Messenger; D023201:CD40 Ligand; C090859:1-((4-methylsulfonyl)phenyl)-3-trifluoromethyl-5-(4-fluorophenyl)pyrazole; D012313:RNA; D003907:Dexamethasone; D008156:Luciferases; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases; D005978:Glutathione; D015232:Dinoprostone