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

被称为发泡剂的一类化学战争威胁物质包括军火库和芥末。 探员们。为第二次世界大战开发的武器化砷基发泡剂库存仍然存在。最近， 在伊拉克和叙利亚，发泡剂被用来对付平民人口，并引起了广泛的疾病和 伤亡人数很少。皮肤暴露于砷会导致水疱性皮肤损害、水泡和皮肤疼痛。 炎症，发展为多器官组织破坏和死亡。四大军火库，路易斯安那， 二苯基氯化砷、二苯基氰化砷和二乙基氯化砷已被确定为潜在威胁 美国国立卫生研究院的化学品抵消了解毒剂/制剂广受欢迎的计划。然而，这些机制 这些军火药是如何在皮肤中表现出如此强大的有害影响的，目前尚不清楚。我们有 最近开发了一种高度敏感的皮肤砷暴露小鼠模型，该模型重述了皮肤 暴露在这些化学物质中的人类的病理学。我们的初步研究表明急性炎症性疾病 而砷化合物造成的组织损伤效应是通过快速启动表观遗传来调节的 组蛋白赖氨酸超乙酰化修饰和染色质重塑。在这方面，溴域4 组蛋白乙酰化标记的阅读器(BRD4)被认为是组蛋白乙酰化标记的有效转录调节因子之一 除其他外，还有诱导性炎症基因。在U54的这个项目-I中，我们建议研究组蛋白 以乙酰化为基础的表观遗传学改变参与皮肤损伤和发展的分子发病机制 可以阻止砷引起的皮肤损伤的解毒剂。提出了三个具体目标：1. 特征组蛋白乙酰化和染色质重塑-与砷暴露相关。此数据将 提供了组蛋白乙酰化的时空调节与潜在的砷之间的关联- 致皮肤损伤。在建立了小鼠皮肤的这些变化之后，我们将确认分子 砷致小型猪急性皮肤损伤的发病机制2：揭示砷致皮肤损伤的分子机制 砷化合物介导组蛋白乙酰化会影响炎症和水泡反应。我们将调查 砷化合物诱导BRD4激活的机制。3：确定治疗干预的窗口 通过使用BRD4抑制剂来防止砷化合物介导的组织损伤。我们的目标是充分描述 行动动力学和评估治疗时间窗(暴露于砷后30、60或120分钟) 这些BRD4抑制剂能够逆转砷诱导的分子变化和潜在的皮肤 发炎/起泡。该项目将与项目II、III和科学核心相结合，就像动物组织将 从局部暴露的动物身上分享。成功逆转皮肤炎症/损害的疗法也将 经验证有减轻肺、肾损伤的作用。成功完成这项提案将导致 现有对军火药毒性的认识发生了范式转变，并开发了一系列新的机制-- 基础解毒剂。

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.