Project 1: Novel Pharmacological Inhibitors of Chemical Vesicants-mediated Cutaneous Injury

这类化学战争威胁剂被称为vesicants，其中包括砷和芥子气 剂.为第二次世界大战开发的武器化砷基起疱剂的库存仍然存在。最近， 在伊拉克和叙利亚，对平民使用了水疱剂，造成了广泛的发病率， 伤亡人数很少皮肤暴露于砷剂会导致水疱性皮肤损伤、水泡和疼痛性皮肤损伤。 炎症，其发展为多器官组织破坏和死亡。四种主要砷剂，路易石， 二苯氯砷、二苯氰砷和二乙基氯砷已被确定为潜在威胁 NIH CounterACT计划高度寻求解毒剂/试剂的化学品。然而，机制 这些砷剂在皮肤中表现出如此强烈的有害作用的原因仍不清楚。我们有 最近开发了一种高度敏感的小鼠皮肤砷暴露模型， 人类暴露于这些化学物质的病理学我们的初步研究表明，急性炎症 砷剂引起的组织损伤效应是通过表观遗传的快速发作介导的， 修饰和染色质重塑通过组蛋白赖氨酸乙酰化。在这方面，溴结构域4 （BRD 4），组蛋白乙酰化标记的阅读器，被认为是一种有效的转录调节因子， 可诱导的炎症基因。在U 54的项目I中，我们计划研究组蛋白 乙酰化为基础的表观遗传学改变参与皮肤病变和发展的分子发病机制 解毒剂可以阻止砷引起的皮肤损伤。提出了三个具体目标： 表征组蛋白乙酰化和染色质重塑-与砷暴露相关。这些数据将 提供组蛋白乙酰化的时空调节与潜在砷之间的相关性- 引起皮肤损伤。在小鼠皮肤中建立这些变化后，我们将确认分子水平。 小型猪急性砷中毒皮肤损伤的发病机制; 2：阐明砷中毒皮肤损伤的分子机制， 砷介导的组蛋白乙酰化影响炎症和起泡反应。我们将探索 砷剂诱导BRD 4活化的机制。3：确定治疗干预的窗口 砷介导的组织损伤，通过管理BRD 4抑制剂。我们的目标是充分描述 作用动力学，并评估治疗时间窗（暴露于砷剂后30、60或120分钟）， 这些BRD 4抑制剂能够逆转砷诱导的分子变化和底层皮肤 炎症/起泡。该项目将与项目II，III和科学核心相结合，因为动物组织将 与局部暴露的动物共享。成功逆转皮肤炎症/损伤的疗法也将 证实肺和肾损伤的减少。成功完成此提案将导致 砷毒性的现有知识的范式转变和一系列新机制的发展， 基于解毒剂。

The class of chemical war-threat agents known as vesicants include among others arsenicals and mustard agents. Stockpiles of weaponized arsenic-based vesicants developed for World War II still exist. Recently, vesicants have been used against civilian populations in Iraq and Syria and caused extensive morbidities and a few casualties. Cutaneous exposure to arsenicals causes vesicular skin lesions, blisters, and painful cutaneous inflammation, which progresses to multi-organ tissue disruption and death. Four major arsenicals, lewisite, diphenylchlorarsine, diphenylcyanoarsine and diethylchloroarsine, have been identified as potential threat chemicals by NIH CounterACT program for which antidotes/agents are highly sought. However, the mechanisms by which these arsenicals manifest such robust deleterious effects in the skin remain undefined. We have recently developed a highly sensitive murine model of cutaneous arsenical exposure, which recapitulates skin pathology of humans exposed to these chemicals. Our preliminary studies indicate that the acute inflammatory and tissue damaging effects caused by arsenicals are mediated through the rapid onset of epigenetic modifications and chromatin remodeling via histone lysine hyperacetylation. In this regard, bromodomain 4 (BRD4), a reader of histone acetylation marks is considered to be one of the potent transcriptional regulator of inducible inflammatory genes besides others. In this Project-I of U54, we propose to investigate histone acetylation-based epigenetic alterations involved in the molecular pathogenesis of skin lesions and development of antidotes that can block arsenical-induced cutaneous injury. Three specific aims are proposed: 1: To characterize histone acetylation and chromatin remodeling-associated with arsenical exposure. This data will provide a correlation between the spatiotemporal regulation of histone acetylation and underlying arsenicals- induced cutaneous injury. After establishing these changes in murine skin we will confirm the molecular pathogenesis of acute skin injury by arsenicals in minipig; 2: To unravel the molecular mechanism by which arsenicals-mediated histone acetylations affect inflammatory and blistering responses. We will probe the mechanisms by which arsenicals induce BRD4 activation. 3: To define the window of therapeutic intervention of arsenicals-mediated tissue damage by administering BRD4 inhibitors. Our goal is to fully characterize the kinetics of action and assess the therapeutic window of time (30, 60 or 120 min after exposure to arsenicals) in which these BRD4 inhibitors are able to reverse arsenical-induced molecular changes and underlying skin inflammation/blistering. This project will integrate with projects II, III, and scientific cores as animal tissues will be shared from topically exposed animals. Therapies successful in reversing skin inflammation/damage will also be verified for the diminution of lung and kidney injury. Successful completion of this proposal will lead to a paradigm shift in the existing knowledge of arsenicals' toxicity and development of novel series of mechanism- based antidotes.