Signaling pathways involved in adenosine triphosphate-induced endothelial cell barrier enhancement
Signaling pathways involved in adenosine triphosphate-induced endothelial cell barrier enhancement
复制标题
DOI：
10.1161/01.res.0000175561.55761.69
复制
发表时间：
2005-07-22
影响因子：
20.1
通讯作者：
Verin, AD
中科院分区：
文献类型：
--
作者：
Kolosova, IA;Mirzapoiazova, T;Verin, AD
炎症激动剂引起的内皮屏障功能障碍是血管渗漏和水肿的常见根本原因。保持屏障完整性的新策略可能会产生深远的临床影响。内皮细胞通过剪切应力和损伤释放的三磷酸腺苷 (ATP) 已被证明在某些情况下可以保护内皮屏障。我们已经证明 ATP 及其非水解类似物增强了培养的内皮细胞单层的屏障特性并引起细胞-细胞连接的重塑。 ATP 引起的胞质 Ca2+ 和 Erk 激活的增加与屏障增强无关。使用生化抑制剂或 siRNA 的实验表明，G 蛋白（特别是 G(alpha q) 和 G(alpha i2)）、蛋白激酶 A (PKA) 和 PKA 底物血管舒张剂刺激的磷蛋白参与 ATP 诱导的屏障增强。 ATP 处理降低了肌球蛋白轻链的磷酸化，并特异性激活了肌球蛋白相关磷酸酶。用 siRNA 消除 G(alpha q) 可阻止 ATP 诱导的肌球蛋白磷酸酶激活。我们得出的结论是，ATP 诱导的屏障增强机制独立于细胞内 Ca2+，但涉及通过新型 G 蛋白偶联机制和 PKA 激活肌球蛋白磷酸酶。
Endothelial barrier dysfunction caused by inflammatory agonists is a frequent underlying cause of vascular leak and edema. Novel strategies to preserve barrier integrity could have profound clinical impact. Adenosine triphosphate (ATP) released from endothelial cells by shear stress and injury has been shown to protect the endothelial barrier in some settings. We have demonstrated that ATP and its nonhydrolyzed analogues enhanced barrier properties of cultured endothelial cell monolayers and caused remodeling of cell-cell junctions. Increases in cytosolic Ca2+ and Erk activation caused by ATP were irrelevant to barrier enhancement. Experiments using biochemical inhibitors or siRNA indicated that G proteins (specifically G(alpha q) and G(alpha i2)), protein kinase A (PKA), and the PKA substrate vasodilator-stimulated phosphoprotein were involved in ATP-induced barrier enhancement. ATP treatment decreased phosphorylation of myosin light chain and specifically activated myosin-associated phosphatase. Depletion of G(alpha q) with siRNA prevented ATP-induced activation of myosin phosphatase. We conclude that the mechanisms of ATP-induced barrier enhancement are independent of intracellular Ca2+, but involve activation of myosin phosphatase via a novel G-protein-coupled mechanism and PKA.