Trek-1 Potassium Channels Protect from Hyperoxia-induced Acute Lung Injury

项目概要： 意义：氧补充（高氧; HO）是最常用的治疗方法， 急性缺氧性呼吸衰竭（ARF）是急性缺氧性呼吸衰竭（ARF）治疗的基础。众所周知， 然而，HO暴露不仅可以促进现有肺损伤，而且还可以引发炎症和屏障 健康的肺功能紊乱。由HO引起的炎症反应特别损害 肺泡上皮和内皮细胞引起细胞凋亡和肺泡屏障破坏。临床上 对HO诱导的急性肺损伤（HALI）的认识增加了对氧毒性的认识， 努力最大限度地减少ARF患者的氧气暴露。尽管临床和实验研究已经发现 HALI的几种潜在机制，目前还没有预防或对抗HALI的疗法， 急性呼吸衰竭病人的住院时间二十年来一直没有改变。这些发现 强调迫切需要确定分子靶点，以促进针对HALI的合理药物设计。 在寻找这些新靶点的过程中，我们发现TREK-1钾通道是潜在的新关键。 HALI的调节剂。我们的初步数据支持HO下调上皮细胞， 内皮TREK-1通道，导致细胞膜去极化，随后开放电压- 门控Ca 2+通道，并因此增加炎症介质分泌，细胞凋亡和 肺泡屏障功能障碍此外，我们认为TREK-1活性的增强可以抵消这一点， 伤害性瀑布。 我们将在三个具体目标中检验这一假设：在目标1中，我们将主要识别细胞类型（-s） 使用上皮和内皮细胞特异性TREK-1 KO小鼠，受HO诱导的TREK-1下调的影响 模型和从这些小鼠分离的原代细胞。在目标2中，我们将确定TREK-1的保护作用。 使用新的TREK-1活化化合物、新的细胞类型特异性TREK-1 过表达小鼠模型和从这些小鼠分离的原代上皮和内皮细胞。在目标3 我们将剖析上皮和内皮TREK-1的结构组成和生物物理特性， 信道在基线和HO条件下，并提出了一种新的信令机制，TREK-1 HALI时，通道可调节炎症和屏障功能障碍。 这项研究将通过建立异常的上皮和内皮TREK来影响急性肺损伤领域。 1信号传导作为HALI中先前未被识别的通路，TREK-1活化作为HALI中的第一个靶向通路。 HALI的治疗方法。

PROJECT SUMMARY: Significance: Oxygen supplementation (hyperoxia; HO) is the most frequently applied therapy for hospitalized patients and the cornerstone of treatment for acute hypoxic respiratory failure (ARF). It is well known, however, that HO exposure can not only promote existing lung injury but also initiate inflammation and barrier dysfunction in otherwise healthy lungs. The inflammatory response evoked by HO is particularly damaging to alveolar epithelial and endothelial cells causing cellular apoptosis and alveolar barrier disruption. Clinically, the recognition of HO-induced acute lung injury (HALI) led to an increased awareness of oxygen toxicity and efforts to minimize oxygen exposure for ARF patients. Although clinical and experimental studies have identified several potential mechanisms underlying HALI, currently no therapies exist to prevent or counteract HALI, and the length of hospitalization of ARF patients has remained unchanged for two decades. These findings underscore the urgent need for identifying molecular targets to facilitate rational drug design against HALI. In the search for such new targets, we discovered TREK-1 potassium channels as potential new key regulators of HALI. Our preliminary data support the novel hypothesis that HO downregulates epithelial and endothelial TREK-1 channels, which results in cell membrane depolarization, subsequent opening of voltage- gated Ca2+ channels, and as a consequence increased inflammatory mediator secretion, cell apoptosis and alveolar barrier dysfunction. Furthermore, we propose that enhancement of TREK-1 activity can counteract this injurious cascade. We will test this hypothesis in three Specific Aims: In Aim1 we will identify the cell type(-s) predominantly affected by HO-induced TREK-1 downregulation, using epithelial and endothelial cell-specific TREK-1 KO mouse models and primary cells isolated from these mice. In Aim 2 we will determine the protective effects of TREK-1 enhancement against HALI using novel TREK-1 activating compounds, new cell type-specific TREK-1 overexpressing mouse models, and primary epithelial and endothelial cells isolated from these mice. In Aim 3 we will dissect the structural composition and biophysical properties of epithelial and endothelial TREK-1 channels at baseline and under HO conditions, and propose a novel signaling mechanism by which TREK-1 channels could regulate inflammation and barrier dysfunction during HALI. This study will impact the field of acute lung injury by establishing aberrant epithelial and endothelial TREK- 1 signaling in the lung as a previously unrecognized pathway in HALI, and TREK-1 activation as the first targeted therapeutic approach against HALI.