Heat shock and lung fluid balance

描述(由申请人提供)：这一新的赠款周期的目标是确定应激蛋白反应(SPR)的激活如何在急性肺损伤(ALL)中保护肺泡毛细血管屏障的完整性。因此，我们建立了一种大鼠和小鼠缺血再灌注(L/R)介导的肺损伤模型，作为ALL的临床相关模型。在初步实验中，SPR的激活抑制了血管内皮生长因子(VEGF)介导的肺内皮细胞渗漏，并阻止了iNOS/NO介导的抑制I/R损伤后肺上皮细胞清除肺泡水肿的作用。我们将检验SPR激活抑制这两条细胞信号通路(血管内皮生长因子、JAK/STAT1诱导的iNOS/NO)的中心假设：(A)首先通过立即将Hsp90从其客户蛋白(这两条信号途径的关键部分)解离，从而使其失去功能，然后(B)通过热休克蛋白的从头合成，如Hsp70，它与Hsp90客户蛋白结合，防止它们的聚集和蛋白酶体降解，直到Hsp90可以与这些蛋白重新复合。在目标1中，我们将对SPR激活如何抑制导致肺内皮细胞屏障渗漏的血管内皮生长因子依赖的细胞信号转导的分子机制提供新的见解。在目标2中，我们将研究SPR激活如何通过抑制JAK/STAT1诱导的iNOS依赖的NO释放对基础离子和cAMP调节的跨肺上皮的离子和液体运输的影响来恢复正常的肺泡液运输。在目的3中，我们将确定SPR介导的抑制血管内皮生长因子诱导的肺血管通透性增加和NO介导的肺泡上皮液转运和蛋白通透性损害在大鼠/小鼠I/R损伤模型中的体内相关性。这些实验将获得重要的治疗意义。事实上，可以使用对人类安全的药物来激活应激反应，作为一种早期预防性治疗，并保护患者免受肺移植中的I/R肺损伤、创伤造成的严重休克或术中缺血。目前的应用将提供新的信息来解释细胞对应激的反应如何保护肺免受血液流动不足造成的损伤。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.