Role of End Binding 3 in Mechanism of vascular permeability

肺血管通透性增加导致富含蛋白质的组织水肿，这是成人的一个重要特征 呼吸窘迫综合征。微管(MT)细胞骨架在高血压发病机制中的作用 血管内皮细胞的通透性还不是很清楚。众所周知，MT正在进行重组，以回应亲- 炎症介质，并因此可能有助于增加内皮通透性的机制。这个 拟议的研究将解决末端结合蛋白-3(EB3)的核心作用，它是一种MT+末端结合因子，在 调节肺血管通透性增加。我们将检验以下假设：(I)EB3是一个主要组成部分 血管内皮细胞-钙粘附素黏附复合体与MT细胞骨架的相互作用 (Ii)EB3介导的MT动力学调控是维持肺微血管基础通透性的关键 对于炎性介质引起的通透性增加。这些研究将解决以下问题 特异性靶点：(1)VE-钙粘附素介导的信号转导在EB3磷酸化和转录调控机制中的作用 抑制MT的生长，从而“由外而内”的信号在建立基础 肺内皮细胞的通透性；以及(2)EB3在调节钙信号转导中的关键作用，从而在 介导内皮细胞通透性增加和肺水肿的发生。我们的期望是 通过了解VE-钙粘附素黏附如何传递EB3磷酸化信号以及EB3如何由此引发 屏障通透性增加将为肺液调节失调的机制提供新的见解 动态平衡。我们将利用最先进的技术，包括活细胞成像，突变的表达 构建、基因转移和小鼠肺部炎症模型以实现特定的目的。

Increases in lung vascular permeability result in protein-rich tissue edema, an important feature of adult respiratory distress syndrome. The role of the microtubule (MT) cytoskeleton in the mechanism of increased endothelial permeability is not well understood. MTs are known to undergo re-organization in response to pro- inflammatory mediators, and may thus contribute to the mechanism of increased endothelial permeability. The proposed studies will address the central role of End Binding protein-3 (EB3), a MT plus-end binding factor, in regulating increased lung vascular permeability. We will test the hypotheses that (i) EB3 is a major component of cross-talk between Vascular Endothelial (VE)-cadherin adhesion complexes and the MT cytoskeleton and (ii) EB3-mediated control of MT dynamics is critical for maintenance of basal permeability of lung microvessels and for permeability increase caused by inflammatory mediators. These studies will address the following Specific Aims: (1) role of VE-cadherin-mediated signaling in the mechanism of EB3 phosphorylation and inhibition of MT growth and, thereby the role of "outside-in" signaling in establishing basal permeability of lung endothelia; and (2) critical role of EB3 in regulating Ca2+ signaling, thus in mediating increased endothelial permeability and development of lung edema. It is our expectation that by understanding how VE-cadherin adhesion signals EB3 phosphorylation and how EB3 thereby elicits the barrier permeability increase will provide novel insights into the mechanisms of dysregulation of lung fluid homeostasis. We will exploit state of the art technologies including live cell imaging, expression of mutant constructs, gene transfer, and murine models of lung inflammation to accomplish the specific aims.