Sphingosine 1-phospbate and activation of endothelial nitric-oxide synthase - Differential regulation of Akt and MAP kinase pathways by EDG and bradykinin receptors in vascular endothelial cells
Sphingosine 1-phospbate and activation of endothelial nitric-oxide synthase - Differential regulation of Akt and MAP kinase pathways by EDG and bradykinin receptors in vascular endothelial cells
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DOI：
10.1074/jbc.m008375200
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发表时间：
2001-04-13
影响因子：
4.8
通讯作者：
Michel, T
中科院分区：
文献类型：
--
作者：
Igarashi, J;Bernier, SG;Michel, T
鞘氨醇1-磷酸(S1P)是一种由G蛋白偶联的EDG受体家族介导的血小板衍生的鞘磷脂，可在内皮细胞中引起多种生物反应。在异源表达系统(Igarashi，J，和Michel，T.(2000)J.Biol Chem)中，S1P刺激EDG受体激活内皮型一氧化氮合酶(ENOS)。275,32363-32370)，然而，调控血管内皮细胞内S1P/EDG调节eNOS的信号通路仍不太清楚。我们现在报道，SIP处理牛主动脉内皮细胞(BAEC)可显著提高eNOS酶活性；对eNOS S1P激活的EC50类似于10NAR。S1P对BAEC内eNOS的激活程度与激动剂缓激肽相当。S1P处理激活Akt，这是一种与eNOS磷酸化有关的蛋白激酶。S1P处理BAEC导致eNOS在Ser(1179)处的磷酸化，Ser(1179)是Akt磷酸化的残基，而该Akt磷酸化位点失活的eNOS突变体表现出减弱S1P诱导的eNOS激活。百日咳毒素、肌醇磷脂3-激酶抑制剂Wortmannin和细胞内钙离子螯合剂BAPTA(1，2-双(氨基苯氧基)乙烷-N，N，N‘，N’-四乙酸)均能抑制S1P诱导的Akt和eNOS的激活。与S1P相反，G蛋白偶联的缓激肽B2受体的激活既不能激活蛋白激酶Akt，也不能促进Ser1179 eNOS的磷酸化，尽管它能很好地激活eNOS酶的活性。了解S1P和缓激肽对蛋白激酶通路的不同调控可能有助于发现血管内皮细胞中eNOS调控的新点。
Sphingosine 1-phosphate (S1P) is a platelet-derived sphingolipid that elicits numerous biological responses in endothelial cells mediated by a family of G protein-coupled EDG receptors, Stimulation of EDG receptors by S1P has been shown to activate the endothelial isoform of nitric-oxide synthase (eNOS) in heterologous expression systems (Igarashi, J,, and Michel, T. (2000) J. Biol Chem. 275, 32363-32370), However, the signaling pathways that modulate eNOS regulation by S1P/EDG in vascular endothelial cells remain less well understood. We now report that SIP treatment of bovine aortic endothelial cells (BAEC) acutely increases eNOS enzyme activity; the EC50 for S1P activation of eNOS is similar to 10 nar. The magnitude of eNOS activation by S1P in BAEC is equivalent to that elicited by the agonist bradykinin. S1P treatment activates Akt, a protein kinase implicated in phosphorylation of eNOS. S1P treatment of BAEC leads to eNOS phosphorylation at Ser(1179), a residue phosphorylated by Akt; an eNOS mutant in which this Akt phosphorylation site is inactivated shows attenuated S1P-induced eNOS activation. S1P-induced activation both of Akt and of eNOS is inhibited by pertussis toxin, by the phosphoinositide 3-kinase inhibitor wortmannin, and by the intracellular calcium chelator BAPTA (1,2-bis(aminophenoxy)ethane-N,N,N',N'-tetraacetic acid). By contrast to S1P, activation of G protein-coupled bradykinin B2 receptors neither activates kinase Akt nor promotes Ser1179 eNOS phosphorylation despite robustly activating eNOS enzyme activity. Understanding the differential regulation of protein kinase pathways by S1P and bradykinin may lead to the identification of new points for eNOS regulation in vascular endothelial cells.