Heat shock and lung fluid balance

描述（由申请人提供）：这个新的资助周期的目标是确定应激蛋白反应（SPR）的激活如何保护急性肺损伤中肺泡毛细血管屏障的完整性（所有）。因此，我们在大鼠和小鼠中开发了缺血-再灌注（I/R）介导的肺损伤模型作为临床相关的All模型。在初步实验中，SPR激活抑制血管内皮生长因子（VEGF）介导的肺内皮渗漏，并阻止了iNOS/NO介导的抑制肺泡水肿消除后，I/R损伤发作的肺上皮。我们将测试SPR激活抑制这两个细胞信号通路的中心假设（VEGF，JAK/Stat 1诱导的iNOS/NO）：（a）首先通过Hsp 90与其客户蛋白质的立即解离，所述客户蛋白质是这两种信号传导途径的关键部分，从而使它们无功能，然后（B）通过热休克蛋白质如Hsp 70的从头合成，其与Hsp 90客户蛋白结合并防止其聚集和蛋白酶体降解，直到Hsp 90可以与蛋白质重新复合。在目标1中，我们将提供新的见解的分子机制，解释SPR激活如何抑制VEGF依赖的细胞信号转导，导致肺内皮屏障的泄漏。在目标2中，我们将研究SPR激活如何通过抑制JAK/Stat 1诱导的iNOS依赖性NO释放对基础和cAMP调节的跨肺上皮的离子和液体转运的影响来恢复正常的肺泡液体转运。在目标3中，我们将在大鼠/小鼠I/R损伤模型中确定SPR介导的VEGF诱导的肺血管通透性增加的抑制和NO介导的肺泡上皮液体转运和蛋白通透性损害的体内相关性，从这些实验中获得的信息具有重要的治疗意义。事实上，应激反应可以使用在人类中安全的药理学试剂作为早期预防性治疗来激活，并保护患者免受肺移植中的I/R肺损伤、创伤引起的严重休克或术中缺血。本申请将提供新的信息来解释细胞对应激的反应如何可以保护肺免受由缺乏血流引起的损伤。研究结果可能有助于确定新的细胞靶点，以开发保护创伤和肺移植患者免受急性肺损伤的治疗方法。

DESCRIPTION (provided by applicant): The goal of this new grant cycle is to determine how the activation of the stress protein response (SPR) protects the integrity of the alveolar capillary barrier in acute lung injury (All). We therefore developed a model of ischemia-reperfusion (l/R)-mediated lung injury in rats and mice as a clinically relevant model of All. In preliminary experiments, SPR activation inhibited the vascular endothelial growth factor (VEGF) mediated lung endothelial leak and prevented the iNOS/NO-mediated inhibition of alveolar edema removal by the lung epithelium after onset of I/R injury. We will test the central hypothesis that SPR activation inhibits these two cell signaling pathways (VEGF, JAK/Stat1-induced iNOS/NO) by: (a) first by an immediate dissociation of Hsp90 from its clients proteins that are critical part of these two signaling pathways, thus rendering them nonfunctional, then (b) by a de novo synthesis of heat shock proteins, such as Hsp70, that binds to Hsp90 client proteins and prevents their aggregation and proteasomal degradation until the Hsp90 can re-complex with the proteins. In aim 1, we will provide new insights into the molecular mechanisms explaining how SPR activation inhibits VEGF-dependent cell signaling that causes the leakage in the lung endothelial barrier. In aim 2 , we will examine how SPR activation restores normal alveolar fluid transport by inhibiting the effect of JAK/Stat1-induced iNOS-dependent NO release in the airspaces on the basal and cAMP-regulated ion and fluid transport across the lung epithelium. In aim 3, we will determine the in vivo relevance of the SPR-mediated inhibition of the VEGF-induced increase in lung vascular permeability and NO-mediated impairment of alveolar epithelial fluid transport and protein permeability in a rat/mouse model of I/R injury.The information that will be obtained from these experiments has an important therapeutic significance. Indeed, the stress response could be activated using pharmacological agents that are safe in humans as an early prophylactic therapy and protect patients from I/R lung injury in lung transplants, severe shock from trauma or intraoperative ischemia. The present application will provide new information to explain how the cellular response to stress may protect the lungs against injury caused by the lack of blood flow. The results of studies may help to identify new cellular targets for the development of treatments that will protect trauma and lung transplant patients from acute lung injury.