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

项目概要： 意义： 补氧（高氧；H2O）是最常用的治疗方法 住院患者和急性缺氧性呼吸衰竭（ARF）治疗的基石。众所周知， 然而，接触 H2O 不仅会促进现有的肺损伤，还会引发炎症和屏障 其他健康的肺部出现功能障碍。 H2O 引起的炎症反应对人体尤其有害 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 H2O 引起的急性肺损伤 (HALI) 的认识提高了人们对氧中毒的认识 努力尽量减少 ARF 患者的氧气暴露。尽管临床和实验研究已经确定 HALI 背后的几种潜在机制，目前尚无预防或抵消 HALI 的疗法，并且 ARF患者的住院时间二十年来一直没有变化。这些发现 强调迫切需要确定分子靶标，以促进针对 HALI 的合理药物设计。 在寻找此类新靶点的过程中，我们发现 TREK-1 钾通道是潜在的新关键 HALI 的监管者。我们的初步数据支持 H2O 下调上皮细胞和 内皮 TREK-1 通道，导致细胞膜去极化，随后打开电压- 门控 Ca2 通道，从而增加炎症介质分泌、细胞凋亡和 肺泡屏障功能障碍。此外，我们建议增强 TREK-1 活性可以抵消这种情况 有害的连锁反应。 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 受 H2O2 诱导的 TREK-1 下调的影响，使用上皮细胞和内皮细胞特异性 TREK-1 KO 小鼠 模型和从这些小鼠中分离出的原代细胞。在目标 2 中，我们将确定 TREK-1 的保护作用 使用新型 TREK-1 激活化合物、新型细胞类型特异性 TREK-1 增强抗 HALI 过表达小鼠模型，以及从这些小鼠中分离的原代上皮细胞和内皮细胞。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 基线和 HO 条件下的通道，并提出了一种新的信号机制，TREK-1 通过该机制 通道可以调节 HALI 期间的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 肺部中的 1 信号传导是 HALI 中以前未被识别的途径，而 TREK-1 激活是第一个目标 针对 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.