title: Induction of cyclooxygenase-2 expression in human myometrial smooth muscle cells by interleukin-1beta: involvement of p38 mitogen-activated protein kinase.
abstract: 1. Human myometrial smooth muscle cells (HMSMCs) in culture were exposed to recombinant human interleukin-1beta (IL-1beta, 10 ng ml-1) for 1 to 24 h. Cyclooxygenase-2 (COX-2) mRNA and protein were rapidly induced, with expression sustained at 24 h. 2. Cycloheximide (10 microg ml-1, 6 h) blocked IL-1beta-induced COX-2 protein expression and super-induced COX-2 mRNA expression. Induction of COX-2 mRNA and protein was blocked by dexamethasone (1 microm, 6 h). 3. IL-1beta-induced COX-2 expression was accompanied by a 3-fold increase of prostaglandin E2 release into the culture medium. 4. IL-1beta induced a transient (5-30 min) activation of p42/44 and p38 mitogen-activated protein kinase (MAPK) enzymes in HMSMCs. Activity of p38 MAPK was monitored by in-gel activity of its substrate MAP kinase-activated protein kinase-2 (MAPKAP kinase-2). Induction of MAPKAP kinase-2 activity was prevented by the p38 MAPK inhibitor SB 203580 (10 microm, 5-30 min). 5. COX-2 protein expression detected after 6 h IL-1beta stimulation was blocked by SB 203580 (10 microM). Exposure of HMSMCs to 10 ng ml-1 IL-1beta for only 30 min induced a level of COX-2 protein expression at 6 h culture similar to that detected in cells exposed to the cytokine for 6 h. 6. Exposure of cells to SB 203580 (10 microM during only the first 30 min of IL-1beta stimulation was effective in blocking COX-2 protein expression assayed after 6 h in culture. 7. This study has established that a transient activation of the p38 MAPK cascade is involved in IL-1beta-stimulated COX-2 expression in human myometrial smooth muscle cells. Induction of COX-2 by IL-1beta in HMSMCs provides support for the hypothesis that autocrine prostaglandin signalling in the myometrium, initiated by elevated intrauterine cytokine concentrations, plays a role in regulating myometrial contractility during labour.
authors.affiliation: Centre for Cardiovascular Biology and Medicine, GKT School of Biomedical Sciences, King's College London, Guy's Campus, London SE1 9RT, UK. simon.bartlett@kcl.ac.uk
authors.forename: S R
authors.initials: SR
authors.lastname: Bartlett
authors.forename: R
authors.initials: R
authors.lastname: Sawdy
authors.forename: G E
authors.initials: GE
authors.lastname: Mann
mesh_terms: D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D051546:Cyclooxygenase 2; D003907:Dexamethasone / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008565:Membrane Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000201:enzymology*; D009215:Myometrium / Q000201:enzymology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D011725:Pyridines; D012333:RNA, Messenger; D003907:Dexamethasone; D003513:Cycloheximide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580