Modulation of Acetylation in the Treatment of Lethal Injuries

 描述（由申请人提供）：出血和脑损伤是平民和军事创伤死亡的主要原因。目前的治疗大多是支持性的，并且不解决由休克和损伤引起的特定细胞功能障碍。乙酰化正迅速成为一种关键的表观遗传机制，调节许多基因的表达（通过调节核组蛋白），以及多种非核蛋白的功能。在NIH资助R 01 GM 84127的资助下，我们已经证明，使用非选择性组蛋白脱乙酰酶（HDAC）抑制剂（pan-HDACI）治疗可以快速激活关键机制，从而改善致死性出血，脓毒症和联合损伤动物模型的生存率。这些结果使我们能够开始一项联邦资助的泛HDACI，丙戊酸（ClinicalTrials.gov标识符NCT 01951560）的I期临床试验。尽管令人兴奋，但由于需要非常大的剂量，使用非选择性HDACI的治疗并不是最佳的，这产生了显著的潜在毒性。HDAC的18种已知亚型具有非常独特的作用、组织分布和生理功能，并且较新的抑制剂具有更高的亚型选择性，因此具有更高的疾病特异性。我们最近已经表明，在脓毒症模型中，用同种型特异性HDACI（iso-HDACI）治疗比泛HDACI更有效，并且初步数据表明，这对于其他致死性损伤也可能是正确的。然而，这一领域需要额外的研究，因为药物的适当选择至关重要，并且抑制错误的HDAC可能是有害的。拟议的研究是我们以前工作的逻辑延伸，并将体内实验与细胞和分子测定相结合，以确定致命损伤的新治疗方法，并提供对潜在机制的重要见解。长期目标：开发新的策略，以最大限度地减少细胞损伤，提高致命损伤后的存活率。具体目标1：在啮齿动物模型中测试在无并发症致死性失血（无多发性创伤）后给予异HDACI的有效性。具体目标2：确定在复苏方案中加入异HDACI是否会改善临床现实模型的结局，其中出血性休克并发多器官损伤和多种微生物污染。具体目标3：在两个不同物种中，确定负责异HDACI在不同损伤后的多器官保护作用的主要机制。方法：我们的计划是进行一系列的动物实验，以解决3个具体目标。首先，将使用简单失血的啮齿动物模型来比较iso-HDACI与pan-HDACI，并了解各种iso-HDACI与其他细胞保护策略之间的相互作用。然后将在出血、多发性创伤和[多种微生物污染（结肠损伤）]的临床现实猪模型中进一步验证在该模型中有效的策略。来自这些实验的组织将用于阐明基因、蛋白质、代谢和重要细胞功能水平的潜在机制。

 DESCRIPTION (provided by applicant): Hemorrhage and brain injuries are the leading causes of death in civilian and military trauma. Current therapies are mostly supportive, and do not address the specific cellular dysfunction caused by shock and injuries. Acetylation is rapidly emerging as a key epigenetic mechanism that regulates the expression of numerous genes (by modulating nuclear histones), as well as the functions of multiple non-nuclear proteins. Funded by the NIH grant R01GM84127, we have demonstrated that treatment with non-selective histone deacetylase (HDAC) inhibitors (pan-HDACI) can rapidly activate key mechanisms that lead to improved survival in animal models of lethal hemorrhage, sepsis, and combined insults. These results have allowed us to start a federally funded phase-I clinical trial of a pan-HDACI, valproic acid (ClinicalTrials.gov identifier NCT01951560). Although exciting, treatment with non-selective HDACI is not optimal due to need for very large doses, which creates a significant potential for toxicities. The 18 known isoforms of HDAC have very distinctive roles, tissue distribution, and physiological functions, and newer inhibitors are more isoform selective, and thus more disease specific. We have recently shown that treatment with isoform specific HDACI (iso-HDACI) is more effective than pan-HDACI in septic models, and preliminary data suggest that this may also be true for other lethal insults. However, this area needs additional investigation because appropriate selection of the drug(s) is critically important, and inhibition f the wrong HDAC can be detrimental. The proposed research is a logical extension of our previous work, and combines in-vivo experiments with cellular and molecular assays to identify novel treatments for lethal insults, and to provide important insights into the underlying mechanisms. Long-term goal: Develop novel strategies to minimize cellular damage and improve survival after lethal insults. Specific aim 1: Test the effectiveness of iso-HDACIs when given after uncomplicated lethal blood loss (without poly-trauma) in a rodent model. Specific aim 2: Determine whether addition of iso-HDACI to resuscitation regimens would improve outcomes in clinically realistic models, where hemorrhagic shock is complicated by multiple organ injuries and polymicrobial contamination. Specific aim 3: Determine the dominant mechanisms that are responsible for the multi-organ protective effects of the iso-HDACI following diverse insults, in two different species. Approach: Our plan is to perform a series of animal experiments to address the 3 specific aims. First, a rodent model of uncomplicated blood loss will be used to compare the iso-HDACI to pan-HDACI, and to understand the interplay between various iso-HDACIs and other cytoprotective strategies. The strategies that work well in this model will then be further validated in a clinically realistic swine model of hemorrhage, poly-trauma, and [polymicrobial contamination (colon injury)]. Tissues from these experiments will be used to elucidate the underlying mechanisms at the level of genes, proteins, metabolism, and important cellular functions.