Platelet-activating factor increases VIE-cadherin tyrosine phosphorylation in mouse endothelial cells and its association with the PtdIns3′-kinase
Platelet-activating factor increases VIE-cadherin tyrosine phosphorylation in mouse endothelial cells and its association with the PtdIns3′-kinase
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DOI：
10.1096/fj.04-2202com
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发表时间：
2005-04-01
期刊：
影响因子：
4.8
通讯作者：
Vilgrain, I
中科院分区：
文献类型：
--
作者：
Hudry-Clergeon, H;Stengel, D;Vilgrain, I
血小板活化因子（PAF）是一种强有力的炎症介质，参与内皮细胞的通透性。本研究旨在表征PAF受体（PAF-R）的表达及其对小鼠内皮细胞粘附连接修饰的特异性贡献。我们证明了PAF-R在小鼠内皮细胞中表达，并且在刺激p42/p44 MAPK和磷脂酰肌醇3-激酶（PtdIns 3 '-kinase）/Akt活性方面具有功能活性。用PAF处理细胞可诱导一系列蛋白质（包括VE-钙粘蛋白）酪氨酸磷酸化的快速时间和剂量依赖性（10（-7）至10（-10）M）增加，这些蛋白质的分子量范围为90至220 kDa，后一效应可被酪氨酸激酶抑制剂除莠霉素A和双酪氨酸磷酸化抑制剂所阻止。我们证明PAF促进了VE-钙粘蛋白与PtdIns 3 '-激酶的多聚体聚集体的形成，这也被除草霉素和双酪氨酸磷酸化抑制。最后，我们通过内皮细胞VE-cadherin的免疫染色显示PAF使粘附连接解离。目前的数据提供了第一个证据，即用PAF处理内皮细胞促进酪氨酸激酶的活化和VE-钙粘蛋白酪氨酸磷酸化和PtdIns 3 '-激酶缔合，最终导致粘附连接的解离。PtdIns 3 '-激酶，作为一个对接蛋白，和VE-钙粘蛋白之间的物理关联，因此可能提供一个有效的机制放大和永久的PAF诱导的细胞活化。
Platelet-activating factor (PAF), a potent inflammatory mediator, is involved in endothelial permeability. This study was designed to characterize PAF receptor (PAF-R) expression and its specific contribution to the modifications of adherens junctions in mouse endothelial cells. We demonstrated that PAF-R was expressed in mouse endothelial cells and was functionally active in stimulating p42/p44 MAPK and phosphatidylinositol 3-kinase (PtdIns3'-kinase)/Akt activities. Treatment of cells with PAF induced a rapid time- and dose-dependent (10(-7) to 10(-10) M) increase in tyrosine phosphorylation of a subset of proteins ranging from 90 to 220 kDa, including the VE-cadherin, the latter effect being prevented by the tyrosine kinase inhibitors herbimycin A and bis-tyrphostin. We demonstrated that PAF promoted formation of multimeric aggregates of VE-cadherin with PtdIns3'-kinase, which was also inhibited by herbimycin and bis-tyrphostin. Finally, we show by immunostaining of endothelial cells VE-cadherin that PAF dissociated adherens junctions. The present data provide the first evidence that treatment of endothelial cells with PAF promoted activation of tyrosine kinases and the VE-cadherin tyrosine phosphorylation and PtdIns3'-kinase association, which ultimately lead to the dissociation of adherens junctions. Physical association between PtdIns3'-kinase, serving as a docking protein, and VE-cadherin may thus provide an efficient mechanism for amplification and perpetuation of PAF-induced cellular activation.