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

急性呼吸抑制综合征(ARDS)可能是一种破坏性的疾病，在此之前 研究主要集中在其高度炎症状态。但是，装载数据 提示免疫抑制参与了这种疾病，其分子机制 目前还不清楚是什么。该项目研究一种独特的分子模型，通过该模型，赖氨酸 乙酰基转移酶被称为氨基酸合成蛋白5-样2(Gcn5l2)的一般控制， 通常通过泛素E3连接酶亚单位Fbxo24在细胞中处理，执行 肺泡上皮细胞死亡与先天免疫相关基因的抑制 组蛋白修饰。我们的假设是，通常由泛素控制的Gcn5l2- 介导的降解，是内毒素反应的先天免疫抑制的执行者 和实验性ARDS的上皮细胞死亡。作为这一假设的推论，我们 提出Gcn5l2化学抑制会减弱乙酰转移酶的活性。因此，在 在这个应用中，我们将首先阐明内毒素是如何通过消除Gcn5l2而增加其水平的。 Fbxo24 E3泛素连接酶介导的实验性肺损伤蛋白分解(目标1)。我们会 专门研究Fbxo24是如何利用互补的 体外和体内遗传模型，然后评估内毒素是如何消除分子的 这些合作伙伴的互动。接下来，我们将优化药物设计，并测试一种 新的小分子，表现出独特而又互补的免疫调节和 二次免疫抑制模型和体外分离的细胞保护特性 人体肺脏系统(目标2)。这些研究将提供一种新的免疫病理生物学模型。 失调，将作为产生小分子调节剂的平台 优化严重危重患者的上皮细胞存活和恢复宿主防御 生病了。

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.