Kozawa O, Suzuki A, Shinoda J, Ozaki N, Oiso Y, Uematsu T
Department of Pharmacology, Gifu University, School of Medicine, Japan.
J Cell Biochem. 1997 Mar 1;64(3):376-81.
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.
在先前的一项研究中，我们发现内皮素 -1（ET -1）在成骨样MC3T3 - E1细胞中可独立于蛋白激酶C激活磷脂酶D。众所周知，磷脂酶D水解磷脂酰胆碱会生成磷脂酸，而磷脂酸可被磷脂酸磷酸水解酶进一步降解为二酰甘油。在本研究中，我们调查了磷脂酶D激活在ET -1刺激成骨样MC3T3 - E1细胞中花生四烯酸释放和前列腺素E2（PGE2）合成过程中的作用。ET -1在0.1 nM至0.1 microM的范围内剂量依赖性地刺激花生四烯酸释放。磷脂酸磷酸水解酶抑制剂普萘洛尔以剂量依赖性方式显著抑制ET -1诱导的花生四烯酸释放以及ET -1诱导的二酰甘油形成。二酰甘油脂肪酶抑制剂1,6 - 双 -（环己氧基羰基氨基）- 己烷（RHC - 80267）显著抑制ET -1诱导的花生四烯酸释放。用普萘洛尔和RHC - 80267预处理也抑制了ET -1诱导的PGE2合成。这些结果强烈表明，磷脂酶D水解磷脂酰胆碱参与了ET -1在成骨样细胞中诱导的花生四烯酸释放。
