Involvement of phospholipase D activation in endothelin-1-induced release of arachidonic acid in osteoblast-like cells.
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.
Kozawa
O
O
Department of Pharmacology, Gifu University, School of Medicine, Japan.
Suzuki
A
A
Shinoda
J
J
Ozaki
N
N
Oiso
Y
Y
Uematsu
T
T
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*
D019332:Endothelin-1; D010713:Phosphatidylcholines; D016718:Arachidonic Acid; D008071:Lipoprotein Lipase; D010739:Phospholipase D; D015232:Dinoprostone