Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden.
J Exp Med. 2012 Jul 2;209(7):1363-77. doi: 10.1084/jem.20111343. Epub 2012 Jun 11.
Regulation of vascular endothelial (VE) growth factor (VEGF)-induced permeability is critical in physiological and pathological processes. We show that tyrosine phosphorylation of VEGF receptor 2 (VEGFR2) at Y951 facilitates binding of VEGFR2 to the Rous sarcoma (Src) homology 2-domain of T cell-specific adaptor (TSAd), which in turn regulates VEGF-induced activation of the c-Src tyrosine kinase and vascular permeability. c-Src was activated in vivo and in vitro in a VEGF/TSAd-dependent manner, and was regulated via increased phosphorylation at pY418 and reduced phosphorylation at pY527. Tsad silencing blocked VEGF-induced c-Src activation, but did not affect pathways involving phospholipase Cγ, extracellular regulated kinase, and endothelial nitric oxide. VEGF-induced rearrangement of VE-cadherin-positive junctions in endothelial cells isolated from mouse lungs, or in mouse cremaster vessels, was dependent on TSAd expression, and TSAd formed a complex with VE-cadherin, VEGFR2, and c-Src at endothelial junctions. Vessels in tsad(-/-) mice showed undisturbed flow and pressure, but impaired VEGF-induced permeability, as measured by extravasation of Evans blue, dextran, and microspheres in the skin and the trachea. Histamine-induced extravasation was not affected by TSAd deficiency. We conclude that TSAd is required for VEGF-induced, c-Src-mediated regulation of endothelial cell junctions and for vascular permeability.
血管内皮（VE）生长因子（VEGF）诱导的通透性调节在生理和病理过程中至关重要。我们表明，VEGF 受体 2（VEGFR2）的酪氨酸磷酸化在 Y951 处促进了 VEGFR2 与 T 细胞特异性衔接子（TSAd）的Src 同源 2 结构域的结合，进而调节了 VEGF 诱导的 c-Src 酪氨酸激酶的激活和血管通透性。c-Src 在体内和体外以 VEGF/TSAd 依赖的方式被激活，并通过 pY418 的磷酸化增加和 pY527 的磷酸化减少来调节。Tsad 沉默阻断了 VEGF 诱导的 c-Src 激活，但不影响涉及磷脂酶 Cγ、细胞外调节激酶和内皮型一氧化氮合酶的途径。VEGF 诱导的从鼠肺中分离的内皮细胞或鼠隐静脉血管中 VE-钙粘蛋白阳性连接的重排依赖于 TSAd 表达，并且 TSAd 在血管内皮连接处与 VE-钙粘蛋白、VEGFR2 和 c-Src 形成复合物。tsad(-/-) 小鼠的血管显示出不受干扰的血流和压力，但 VEGF 诱导的通透性受损，如皮肤和气管中 Evans 蓝、葡聚糖和微球的渗出所测量的。组胺诱导的渗出不受 TSAd 缺乏的影响。我们得出结论，TSAd 是 VEGF 诱导的、c-Src 介导的内皮细胞连接和血管通透性调节所必需的。
