Pulmonary endothelial cell barrier enhancement by FTY720 does not require the SIP1 receptor
Pulmonary endothelial cell barrier enhancement by FTY720 does not require the SIP1 receptor
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DOI：
10.1016/j.cellsig.2007.03.011
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发表时间：
2007-08-01
影响因子：
4.8
通讯作者：
Singleton, P. A.
中科院分区：
文献类型：
--
作者：
Dudek, S. M.;Camp, S. M.;Singleton, P. A.
需要新的治疗策略来逆转在炎性疾病状态如急性肺损伤期间发生的内皮细胞（EC）屏障完整性的丧失。我们先前在体内和体外证明了血小板衍生磷脂，鞘氨醇1-磷酸（S1 P）通过连接S1 P（1）受体有效的EC屏障增强。S1 P类似物FTY 720通过假定的S1 P受体连接类似地发挥屏障保护血管作用。我们研究了S1 P受体在鞘脂介导的人肺EC屏障增强中的作用。S1 P和FTY诱导的持续的，剂量依赖性的屏障增强，反映了跨内皮电阻（TER），这是由百日咳毒素表明Gi偶联受体激活废除增加。FTY介导的TER增加表现出相对于S1 P反应的显著延迟的发作和强度。S1 P（1）R表达的减少（通过siRNA）减弱了S1 P诱导的TER升高，而对FTY的TER反应不受影响。S1 P和FTY均能迅速（5 min内）诱导膜脂筏中S1 P（1）R的积累，但只有S1 P能促进苏氨酸残基上S1 P（1）R的磷酸化。抑制PI 3激酶活性减弱S1 P介导的TER增加，但未能改变FTY诱导的TER升高。最后，S1 P，而不是FTY，诱导显着的肌球蛋白轻链磷酸化和戏剧性的肌动蛋白细胞骨架重排，而减少表达的细胞骨架效应，Rac 1和cornein（通过siRNA），衰减S1 P，但不是FTY诱导的TER升高。这些结果从机制上表征了FTY 720对肺血管屏障的调节，提示了一种调节血管通透性的新的屏障增强途径。(c)2007年爱思唯尔公司All rights reserved.
Novel therapeutic strategies are needed to reverse the loss of endothelial cell (EC) barrier integrity that occurs during inflammatory disease states such as acute lung injury. We previously demonstrated potent EC barrier augmentation in vivo and in vitro by the platelet-derived phospholipid, sphingosine 1-phosphate (S1P) via ligation of the S1P(1) receptor. The S1P analogue, FTY720, similarly exerts barrier-protective vascular effects via presumed S1P, receptor ligation. We examined the role of the S1P, receptor in sphingolipid-mediated human lung EC barrier enhancement. Both S1P and FTY-induced sustained, dose-dependent barrier enhancement, reflected by increases in transendothelial electrical resistance (TER), which was abolished by pertussis toxin indicating Gi-coupled receptor activation. FTY-mediated increases in TER exhibited significantly delayed onset and intensity relative to the S1P response. Reduction of S1P(1)R expression (via siRNA) attenuated S1P-induced TER elevations whereas the TER response to FTY was unaffected. Both S1P and FTY rapidly (within 5 min) induced S1P(1)R accumulation in membrane lipid rafts, but only S1P stimulated S1P(1)R phosphorylation on threonine residues. Inhibition of PI3 kinase activity attenuated S1P-mediated TER increases but failed to alter FTY-induced TER elevation. Finally, S1P, but not FTY, induced significant myosin light chain phosphorylation and dramatic actin cytoskeletal rearrangement whereas reduced expression of the cytoskeletal effectors, Rac1 and cortactin (via siRNA), attenuated S1P-, but not FTY-induced TER elevations. These results mechanistically characterize pulmonary vascular barrier regulation by FTY720, suggesting a novel barrier-enhancing pathway for modulating vascular permeability. (c) 2007 Elsevier Inc. All rights reserved.