Src Regulation of Lung Endothelial Barrier Function

在项目4中，我们将测试以下假设：（i）Nox 2依赖的氧化剂信号传导激活Src激酶依赖的 ICAM-1磷酸化，从而在肺循环中募集PMN， (ii)ICAM-1的Src磷酸化反过来延长了Caveolin-1的Src活化和磷酸化， 发动蛋白-2，从而触发小窝介导的白蛋白转胞吞作用和内皮通透性过高。 这些研究将解决以下具体目标：（1）PI 3-kinase，PKC zeta，Nox 2和Src的作用 信号传导，以及细丝蛋白A的Akt磷酸化在ICAM-1磷酸化、聚集和 肺微血管内皮细胞ICAM-1结合亲和力和肺内PMN摄取迅速增加; 磷酸化ICAM-1在招募SHP 2和延长Src活化中的作用，从而延长小窝蛋白-1和 发动蛋白-2激活，从而刺激小窝介导的转胞吞作用和白蛋白的高渗透性。 项目4将描述介导ICAM-1在细胞凋亡后修饰的信号机制， 肺微血管内皮细胞，使用成像，细胞生物学，生物化学和生理 接近。因此，我们将确定内皮细胞ICAM-1如何转变为高亲和力状态，并促进内皮细胞的增殖。 中性粒细胞粘附和隔离，并通过转胞吞作用诱导小窝介导的高通透性 白蛋白。希望这些研究将导致对早期PMN介导的肺损伤的新认识。 炎症反应及其与肺血管高通透性的偶联。关键信号的识别 ICAM-1介导的内皮粘附性和小窝介导的白蛋白转运激活的枢纽 该途径可能提供针对炎性肺损伤的新的治疗靶点。

In Project 4, we will test the hypotheses that (i) Nox2-dependent oxidant signaling activates Src kinasedependent ICAM-1-phosphorylation and thereby the recruitment of PMNs in the pulmonary circulation, and that (ii) Src phosphorylation of ICAM-1 in turn protracts Src activation and phosphorylation of caveolin-1 and dynamin-2, thereby triggering caveolae-mediated transcytosis of albumin and endothelial hyper-permeability. These studies will address the following Specific Aims: (1) role of PI3-kinase, PKC zeta, Nox2, and Src signaling, and of Akt phosphorylation of filamin A in the mechanism of ICAM-1 phosphorylation, clustering, and rapid increase in ICAM-1 binding affinity in lung microvascular endothelial cells and PMN uptake in lungs; (2) role of phospho-ICAM-1 in recruitment of SHP2 and protracting Src activation and thereby caveolin-1 and dynamin-2 activation, and thus stimulating caveolae-mediated transcytosis and hyper-permeability of albumin. Project 4 will delineate the signaling mechanisms mediating the post-translafional modification of ICAM-1 in pulmonary microvessel endothelial cells using imaging, cell biology, biochemical, and physiological approaches. We will thereby establish how endothelial cell ICAM-1 shifts to a high-affinity state and promotes PMN adhesion and sequestration and also induces caveolae-mediated hyper-permeability via the transcytosis of albumin. These studies it is hoped will lead to a new understanding of the early PMN-mediated lung inflammatory response and its coupling to lung vascular hyper-permeability. Identification of the key signaling hubs of ICAM-1-mediated endothelial adhesivity and activation of the caveolae-mediated albumin transport pathway is likely to provide novel therapeutic targets directed against infiammatory lung injury.