title: Prostaglandin E(2) regulates the level and stability of cyclooxygenase-2 mRNA through activation of p38 mitogen-activated protein kinase in interleukin-1 beta-treated human synovial fibroblasts.
abstract: The p38 MAPK mediates transcriptional and post-transcriptional control of cyclooxygenase-2 (COX-2) mRNA following interleukin-1(IL-1)/lipopolysaccharide cellular activation. We explored a positive feedback, prostaglandin E(2) (PGE(2))-dependent stabilization of COX-2 mRNA mediated by the p38 MAPK cascade in IL-1 beta-stimulated human synovial fibroblasts. We observed a rapid (5 min), massive (>30-fold), and sustained (>48 h) increase in COX-2 mRNA, protein, and PGE(2) release following a recombinant human (rh) IL-1 beta signal that was inhibited by NS-398, a COX-2 inhibitor, and SB202190, a selective, cell-permeable p38 MAPK inhibitor. PGE(2) completely reversed NS-398-mediated inhibition but not SB202190-dependent inhibition. The eicosanoid didn't potentiate IL-1 beta-induced COX-2 expression nor did it activate COX-2 gene expression in quiescent cells. Transfection experiments with a human COX-2 promoter construct revealed a minor element of p38 MAPK-dependent transcriptional control after IL-1 beta stimulation. p38 MAPK synergized with the cAMP/cAMP-dependent protein kinase cascade to transactivate the COX-2 promoter. When human synovial fibroblasts were activated with rhIL-1 beta for 3-4 h (steady state) followed by washout, the elevated levels of COX-2 mRNA declined rapidly (<2 h) to control levels. If PGE(2), unlike EP2/3 agonists butaprost and sulprostone, was added to fresh medium, COX-2 mRNA levels remained elevated for up to 16 h. SB202190 or anti-PGE(2) monoclonal antibody compromised the stabilization of COX-2 mRNA by PGE(2). Deletion analysis using transfected chimeric luciferase-COX-2 mRNA 3'-untranslated region reporter constructs revealed that IL-1 beta increased reporter gene mRNA stability and translation via AU-containing distal regions of the untranslated region. This response was mediated entirely by a PGE(2)/p38 MAPK-dependent process. We conclude that the magnitude and duration of the induction of COX-2 mRNA, protein, and PGE(2) release by rhIL-1 beta is primarily the result of PGE(2)-dependent stabilization of COX-2 mRNA and stimulation of translation, a process involving a positive feedback loop mediated by the EP4 receptor and the downstream kinases p38 MAPK and, perhaps, cAMP-dependent protein kinase.
authors: Osteoarthritis Research Unit, Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montréal, H2l 4M1 Québec, Canada.
authors: W H
authors: WH
authors: Faour
authors: Y
authors: Y
authors: He
authors: Q W
authors: QW
authors: He
authors: M
authors: M
authors: de Ladurantaye
authors: M
authors: M
authors: Quintero
authors: A
authors: A
authors: Mancini
authors: J A
authors: JA
authors: Di Battista
mesh_terms: D001483:Base Sequence; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D017931:DNA Primers; D015232:Dinoprostone / Q000502:physiology*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000502:physiology; D058309:Receptors, Prostaglandin E, EP4 Subtype; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013583:Synovial Membrane / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D017931:DNA Primers; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; C545650:PTGER4 protein, human; D012333:RNA, Messenger; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; D011994:Recombinant Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015232:Dinoprostone