title: Regulation of bone morphogenetic protein-2 expression by endogenous prostaglandin E2 in human mesenchymal stem cells.
abstract: Cyclooxygenase (COX)-2 is generally known as an inducible enzyme, and it produces arachidonic acid to prostaglandin E2 (PGE2), which modulates bone metabolism. Here, we investigated the expression and role of COX isomers in human mesenchymal stem cells. Human mesenchymal stem cells constitutively expressed COX-2 as well as COX-1, and secretion of PGE2 was completely inhibited by NS-398, a specific inhibitor of COX-2. Levels of secreted PGE2 were strikingly higher in human mesenchymal stem cells than in osteoblastic cells differentiated from the mesenchymal cells. This higher production of PGE2 in mesenchymal stem cells was due to higher expression of membrane-associated PGE synthase (mPGES) regulated by early growth response factor-1 (Egr-1). Treatment of human mesenchymal stem cells with NS-398 suppressed expression of bone morphogenetic protein-2 (BMP-2). The suppression of BMP-2 by NS-398 was abrogated by an EP4 receptor agonist as well as by PGE2. Moreover, BMP-2 expression was suppressed by an EP4 receptor antagonist. These data indicate that PGE2 produced by COX-2 increases BMP-2 expression via binding the EP4 receptor.
authors.affiliation: Department of Cellular Physiological Chemistry, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Arikawa
authors.forename: Ken
authors.initials: K
authors.lastname: Omura
authors.forename: Ikuo
authors.initials: I
authors.lastname: Morita
mesh_terms: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism* / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism; D009578:Nitrobenzenes / Q000494:pharmacology; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics; D018078:Receptors, Prostaglandin E / Q000819:agonists; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013449:Sulfonamides / Q000494:pharmacology; D016212:Transforming Growth Factor beta
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D009578:Nitrobenzenes; C545650:PTGER4 protein, human; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013449:Sulfonamides; D016212:Transforming Growth Factor beta; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone