title: Involvement of phospholipase D activation in endothelin-1-induced release of arachidonic acid in osteoblast-like cells.
abstract: In a previous study, we have that endothelin-1 (ET-1) activates phospholipase D independently from protein kinase C in osteoblast-like MC3T3-E1 cells. It is well recognized that phosphatidylycholine hydrolysis by phospholipase D generates phosphatidic acid, which can be further degraded by phosphatidic acid phosphohydrolase to diacylglycerol. In the present study, we investigated the role of phospholipase D activation in ET-1 stimulated arachidonic acid release and prostaglandin E2 (PGE2) synthesis in osteoblast-like MC3T3-E1 cells. ET-1 stimulated arachidonic acid dose-dependently in the range between 0.1 nM and 0.1 microM. Propranolol, an inhibitor of phosphatidic acid phosphohydrolase, significantly inhibited the ET-1-induced arachidonic acid release in a dose-dependent manner as well as the ET-1-induced diacylglycerol formation. 1,6-bis-(cyclohexyloxyminocarbonylamino)-hexane (RHC-80267), an inhibitor of diacylglycerol lipase, significantly suppressed the ET-1-induced arachidonic acid release. The pretreatment with propranolol and RHC-80267 also inhibited the ET-1-induced PGE2 synthesis. These results strongly suggest that phosphatidylcholine hydrolysis by phospholipase D is involved in the arachidonic acid release induced by ET-1 in osteoblast-like cells.
authors.affiliation: Department of Pharmacology, Gifu University, School of Medicine, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Kozawa
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: J
authors.initials: J
authors.lastname: Shinoda
authors.forename: N
authors.initials: N
authors.lastname: Ozaki
authors.forename: Y
authors.initials: Y
authors.lastname: Oiso
authors.forename: T
authors.initials: T
authors.lastname: Uematsu
mesh_terms: D016475:3T3 Cells; D000818:Animals; D016718:Arachidonic Acid / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry; D002460:Cell Line; D015232:Dinoprostone / Q000096:biosynthesis*; D019332:Endothelin-1 / Q000502:physiology*; D004789:Enzyme Activation; D005163:Factor Analysis, Statistical; D006868:Hydrolysis; D008071:Lipoprotein Lipase / Q000235:genetics; D051379:Mice; D010006:Osteoblasts; D010713:Phosphatidylcholines / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D010713:Phosphatidylcholines; D016718:Arachidonic Acid; D008071:Lipoprotein Lipase; D010739:Phospholipase D; D015232:Dinoprostone