A Transcriptional Program Modulating Epithelial Death and Innate Function - Project 1

急性呼吸抑制综合征（ARDS）可能是一种毁灭性的疾病， 研究主要集中在其高度炎症状态。然而，安装数据 表明免疫抑制参与了这种疾病， 目前还不清楚该项目研究了一种独特的分子模型， 乙酰转移酶称为氨基酸合成的一般控制蛋白5-样2（Gcn 512）， 通常被泛素E3连接酶亚基Fbxo 24在细胞中处理， 肺泡上皮细胞死亡和先天免疫相关基因的抑制， 组蛋白修饰我们的假设是Gcn 5l 2，通常由泛素控制- 介导的降解，是先天性免疫抑制的内毒素应答执行者 和上皮细胞死亡。作为这一假设的推论，我们 提出Gcn 5l 2化学抑制将减弱乙酰转移酶活性。所以在 在本申请中，我们将首先阐明内毒素是如何通过消除Gcn 5l 2的活性来增加Gcn 5l 2水平的。 Fbxo 24 E3泛素连接酶介导的实验性肺损伤中的蛋白水解（目的1）。我们将 具体地研究Fbxo 24如何靶向Gcn 5l 2用于其降解， 体外和体内遗传模型，然后评估内毒素如何消除分子 这些合作伙伴的互动。下一步，我们将优化药理学设计，并测试一个 一种新的小分子，其表现出独特的但互补的免疫调节作用， 在免疫抑制的2次打击模型中和在离体分离的 人肺系统（目标2）。这些研究将提供一种新的免疫病理生物学模型 调节异常，其将作为产生小分子调节剂的平台， 优化上皮细胞存活并恢复严重危重患者的宿主防御 病

Acute Respiratory Depress Syndrome (ARDS) can be a devastating disorder and prior studies have focused mainly on its hyper-inflammatory state. However, mounting data suggest that immune suppression partakes in this disorder, the molecular mechanisms of which remain unclear. This Project investigates a unique molecular model whereby a lysine acetyltransferase termed general control of amino acid synthesis protein 5-like 2 (Gcn5l2), normally targeted for its disposal in cells by a ubiquitin E3 ligase subunit, Fbxo24, executes alveolar epithelial cell death and suppression of genes involved in innate immunity through histone modification. Our hypothesis is that Gcn5l2, normally kept in check by ubiquitin- mediated degradation, is an endotoxin-responsive executioner of innate immune suppression and epithelial cellular death in experimental ARDS. As a corollary to this hypothesis, we propose that Gcn5l2 chemical inhibition will attenuate acetyltransferase activity. Hence, in this application we will first elucidate how endotoxin increases Gcn5l2 levels by abrogating its Fbxo24 E3 ubiquitin ligase mediated proteolysis in experimental lung injury (Aim 1). We will specifically investigate how Fbxo24 targets Gcn5l2 for its degradation using complementary in vitro and in vivo genetic models and then evaluate how endotoxin abrogates molecular interaction of these partners. Next, we will optimize the pharmacologic design and test a novel small molecule that exhibits distinct, and yet complementary immune modulatory and cytoprotective properties in 2-hit models of immune suppression and in an ex vivo isolated human lung system (Aim 2). These studies will provide a new pathobiologic model of immune dysregulation that will serve as a platform for generating small molecule modulators that optimize epithelial cell survival and restore host defense in subjects with severe critical illness.