Piezo1 Mediated Adjustments in Lung Fluid Balance

项目摘要/摘要 在黏附连接(AJs)水平上的肺内皮屏障完整性是肺液稳态所必需的。 导致肺血管内皮细胞屏障完整性丧失的关键机制 肺水肿是肺毛细血管对高压反应的“应激衰竭”。虽然大家都知道AJ， 由VE-钙粘蛋白和相关的连环蛋白组成，限制内皮通透性，对此知之甚少 机械力，特别是血管壁张力，如何控制内皮通透性和肺水肿。 我们的支持数据描述了静水压力在激活微血管中的潜在重要作用。 机械传感器Piezo1在内皮细胞(ECs)和增加内皮屏障通透性方面具有重要作用。我们 观察到Piezo1的激活诱导了细胞内的钙信号转导，进而导致磷酸化 VE-钙粘附素和微血管通透性增加。这些发现第一次将 内皮细胞暴露在Piezo1的激活和AJ的拆解下的张力，导致 基本问题“Piezo1感受到的内皮细胞质膜张力如何激活VE- 钙粘蛋白磷酸化，从而扰乱AJs？“在目标1中，我们将确定微血管的作用 压力激活肺内皮细胞机械感觉通道Piezo1及Piezo1的S调节作用 内皮通透性和肺液平衡。我们将确定Src依赖的磷酸化 Piezo1激活内皮细胞内钙信号是否需要Piezo1，以及这是否因此介导了 内皮通透性。在目标2中，我们将确定Piezo1信号在介导拆卸中的作用 通过VE-钙粘附素的磷酸化和增加血管内皮细胞的通透性，促进AJs的生长。在这里，我们将 确定Piezo1激活下游的信号通路，诱导VE-钙粘蛋白和 Ve-钙粘附素内吞，从而分解AJ。在目标3中，我们将确定Piezo1在 介导肺血管高通透性(“应激衰竭”)和左心衰相关的水肿 (LHF)。这些研究将探讨Piezo1在肺性心脏病发病机制中的病理生理学相关性。 LHF引起的肺微血管压升高引起的水肿。上述研究将是必不可少的。 为了解Piezo1在增加肺微血管通透性中的作用，目的是确定新的 高压性肺水肿的治疗靶点。

PROJECT SUMMARY / ABSTRACT Lung endothelial barrier integrity at the level of adherens junctions (AJs) is required for lung fluid homeostasis. A crucial mechanism contributing to the loss of endothelial barrier integrity in conditions such as pulmonary edema is “stress failure” of pulmonary capillaries in response to high pressure. While it is known that AJs, comprised of VE-cadherin and associated catenin proteins, restrict endothelial permeability, little is known about how mechanical forces, specifically vessel wall tension, control endothelial permeability and pulmonary edema. Our Supporting Data describe the potentially important role of hydrostatic pressure in microvessels in activating the mechanosensor Piezo1 in endothelial cells (ECs) and in increasing endothelial barrier permeability. We observed that activation of Piezo1 induced intracellular Ca2+ signaling, which in turn, caused phosphorylation of VE-cadherin and increased microvascular permeability. These findings have for the first time linked increased tension to which ECs are exposed to the activation of Piezo1 and disassembly of AJs, leading to the fundamental question “how does tension sensed at the plasma membrane of ECs by Piezo1 activate VE- cadherin phosphorylation and thereby disrupt AJs?” In Aim 1, we will determine the role of microvessel pressure in activating the mechanosensor channel Piezo1 in lung ECs and Piezo1’s role in regulating endothelial permeability and lung fluid balance. We will determine whether Src dependent phosphorylation of Piezo1 is required for Piezo1 activated Ca2+ signaling in ECs and whether this thereby mediates increased endothelial permeability. In Aim 2, we will determine the role of Piezo1 signaling in mediating disassembly of AJs through phosphorylation of VE-cadherin, and in increasing endothelial permeability. Here, we will identify the signaling pathway downstream of Piezo1 activation that induces phosphorylation of VE-cadherin and VE-cadherin endocytosis and thus disassemble the AJs. In Aim 3, we will determine the role of Piezo1 in mediating lung vascular hyper-permeability (“stress failure”) and edema associated with left heart failure (LHF). These studies will address the pathophysiological relevance of Piezo1 in the mechanism of pulmonary edema resulting from LHF-induced increases in lung microvessel pressure. The above studies will be essential for understanding the role of Piezo1 in increasing lung microvessel permeability, with the goal of identifying new therapeutic targets for high pressure-induced pulmonary edema.