Modulation of Acetylation in the Treatment of Lethal Hemorrhagic Shock

描述(申请人提供)：出血是平民和战斗创伤死亡的主要原因，有效的复苏策略有可能挽救许多人的生命。然而，常规复苏可加重失血性休克引起的细胞损伤。在亚细胞水平上，失血性休克和复苏可以改变基因表达，并损害后续下游生存通路的调节。核组蛋白是已知的基因转录调节因子，我们先前已经证明，用组蛋白脱乙酰酶抑制剂(HDACi)治疗通过多个赖氨酸残基的特异性超乙酰化(“表观遗传调节”)来增强基因转录，减轻器官损伤，并提高致命出血后的早期存活率。新出现的证据还表明，非组蛋白的乙酰化可能在细胞过程中发挥同样重要的调控作用，而不依赖于转录。因此，使用HDACi(有或没有常规液体复苏)似乎是治疗致命出血的一种非常有前途的策略。然而，在将这些令人兴奋的发现转化为临床实践之前，必须清楚地确定最有效的HDACi治疗方法(例如，试剂、剂量和时机)以及确切的作用机制。长期目标：制定策略，最大限度地减少细胞损伤，提高致命出血后的存活率。具体目的1：确定组蛋白脱乙酰酶抑制剂(HDACi)在致死性非复苏性出血后使用时，是否能引起最明显的乙酰化？次目标1：确定实现最大蛋白质乙酰化的HDACi的最佳剂量。次目标2：通过重复使用HDACi，确定蛋白质的超乙酰化是否能持续更长时间。次目标3：确定来自不同HDACi基团的结合剂是否能增强蛋白质乙酰化。具体目的2：确定在复苏液中添加HDACi是否有利？次要目标1：确定在常规液体中添加HDACi是否会减弱细胞损伤的标志物并提高存活率？次目标2：确定HDACi治疗能否与高渗液复苏相结合以达到协同效应？具体目的3：确定HDACi发挥保护作用的主要机制。次目标1：确定组蛋白乙酰化改变其转录的基因(“表观遗传机制”)，并研究其对下游蛋白的影响。次目标2：确定HDACi的保护作用是否是由于非组蛋白蛋白的直接乙酰化。与公共卫生相关：治疗大量失血的传统方法已被证明无效，甚至可能使结果恶化。我们的研究表明，通过加强细胞中自然存在的基本保护机制，可以显著提高存活率。我们项目的目的是改进这一新的方法，并开发有效的策略来治疗致命的失血。

DESCRIPTION (provided by applicant): Hemorrhage is the leading cause of death in civilian and combat trauma, and effective resuscitation strategies have the potential of saving many lives. However, conventional resuscitation can exacerbate cellular injury caused by hemorrhagic shock. At a sub-cellular level, hemorrhagic shock and resuscitation can alter gene expression, and impair the regulation of subsequent downstream survival pathways. Nuclear histone proteins are known regulators of gene transcription, and we have previously shown that treatment with histone deacetylase inhibitors (HDACI) enhances gene transcription through specific hyperacetylation at multiple lysine residues ("epigenetic regulation"), attenuates organ damage, and improves early survival after lethal hemorrhage. Emerging evidence also suggests that acetylation of non-histone proteins may play an equally important regulatory role in cellular processes, independent of transcription. Thus, administration of HDACI (with or without conventional fluid resuscitation) appears to be a very promising strategy for the treatment of lethal hemorrhage. However, before these exciting findings can be translated into clinical practice, the most effective HDACI treatment (e.g. agent, dose, and timing), and the precise mechanisms of action must be clearly identified. LONG TERM GOALS: Develop strategies to minimize cellular injury and improve survival after lethal hemorrhage. SPECIFIC AIM 1: Identify the histone deacetylase inhibitor (HDACI) treatment that induces the most pronounced acetylation, when given after lethal non-resuscitated hemorrhage? Sub aim 1: Identify the optimal doses of HDACI for achieving maximum protein acetylation. Sub aim 2: Determine whether protein hyperacetylation can be sustained for longer duration through repeated administration of HDACI. Sub aim 3: Determine whether combining agents from different HDACI groups can enhance protein acetylation. SPECIFIC AIM 2: Establish whether addition of HDACI to resuscitation fluids is advantageous? Sub aim 1: Ascertain whether addition of HDACI to conventional fluids attenuates markers of cellular injury and improves survival? Sub aim 2: Determine whether HDACI treatment can be combined with hypertonic fluid resuscitation to achieve synergistic effects? SPECIFIC AIM 3: Determine the dominant mechanisms that are responsible for exerting the protective effects of HDACI. Sub aim 1: Identify the genes whose transcription is altered by the acetylation of histone proteins ("epigenetic mechanisms"), and study its impact on downstream proteins. Sub aim 2: Identify whether the protective effects of HDACI are due to direct acetylation of non-histone proteins. PUBLIC HEALTH RELEVANCE: Conventional methods of treating massive blood loss have proven to be ineffective, and may even worsen the outcome. Our research has shown that survival can be dramatically improved by enhancing the essential protective mechanisms that are naturally present in the cells. The aim of our project is to refine this novel approach, and develop effective strategies for the treatment of lethal blood loss.