Clinical and Proteomic Characterization of Nucleosomes in Pediatric Acute Respiratory Distress Syndrome

项目总结/摘要 急性呼吸窘迫综合征（ARDS）是以急性发作的弥漫性、双侧肺动脉高压为特征的一种呼吸系统疾病。 水肿和严重低氧血症不能完全由心力衰竭解释。该综合症影响了45，000名儿童， 在美国，每年有10%的儿童在儿科重症监护室接受机械通气。 单位（PICU），相关死亡率高达30%。感染是小儿ARDS的主要原因， 高达80%的病例发生在感染性肺炎或非肺脓毒症的情况下。 尽管有几项试验，但没有针对ARDS的特定药物治疗，支持性治疗仍然存在 是治疗的主要手段。在儿童中，缺乏治疗进一步加剧了治疗的不确定性。 管理，因为指南通常是从成人ARDS推断的，适用性不确定。然而，在这方面， 小儿ARDS具有独特的流行病学和结果特征，需要对此进行专门的研究。 人口最近的证据表明，核小体，DNA/组蛋白复合物释放到 细胞损伤后核染色质降解导致的循环，作为全身性脓毒症的致病因素 和创伤相关的成人呼吸窘迫综合征通常位于细胞核内，核小体释放到细胞核中， 循环对多种细胞类型有毒，提供了一种新的机制，将不同的刺激性损伤与 随后的肺损伤。然而，核小体是否是小儿ARDS的致病因素尚不清楚。的 该建议的广泛目标是：1）确定核小体水平之间的关联， 儿童ARDS队列的结果; 2）通过以下方法确定致病核小体的组成： 鉴定特定的组蛋白和相关的翻译后修饰; 3）证明致病性 在体外细胞培养物和体内啮齿动物模型中的后修饰的和未修饰的组蛋白;和4） 发展必要的技能，成为一个成功的转化科学家在儿科肺损伤的重点 流行病学和蛋白质组学培训。拟议的研究利用现有的基础设施， 费城儿童医院和宾夕法尼亚大学在儿科ARDS中进行队列研究 并进行新的蛋白质组学分析。一个多元化和经验丰富的导师团队，在基本， 翻译和临床研究，已经组装，通过严格的培训计划提供指导 涉及研究行为，先进的流行病学分析和蛋白质组学教学， 导师制拟议的研究将建立血浆核小体在儿科ARDS中的相关性， 提供了一种分离和分析核小体相关蛋白的新技术，并提高了我们的 了解循环组蛋白的致病性。我们将利用这些见解来研究新的疗法 我将在临床研究和蛋白质组学方面获得必要的培训，以成熟成为一名 独立的翻译科学家，致力于改善重症儿童的预后。

PROJECT SUMMARY/ABSTRACT Acute respiratory distress syndrome (ARDS) is characterized by acute onset of diffuse, bilateral pulmonary edema and severe hypoxemia not fully explained by cardiac failure. The syndrome affects 45,000 children in the United States annually, representing 10% of mechanically ventilated children in pediatric intensive care units (PICUs), with an associated mortality rate of up to 30%. Infection is the leading cause of pediatric ARDS, with up to 80% of cases occurring in the setting of either infectious pneumonia or non-pulmonary sepsis. There are no specific pharmacological therapies for ARDS despite several trials, and supportive care remains the mainstay of treatment. In children, a lack of therapies is further compounded by uncertainty in management, as guidelines are typically extrapolated from adult ARDS, with uncertain applicability. However, pediatric ARDS possesses a distinct epidemiologic and outcome profile, necessitating studies specific to this population. Recent evidence has implicated nucleosomes, the DNA/histone complexes released into circulation as a result of nuclear chromatin degradation after cellular damage, as pathogenic in systemic sepsis and trauma-associated ARDS in adults. Normally located within the nucleus, nucleosomes released into the circulation are toxic to multiple cell types, offering a novel mechanism linking diverse inciting insults with subsequent lung injury. However, whether nucleosomes are pathogenic in pediatric ARDS is unknown. The broad objectives of this proposal are to 1) determine the association between nucleosome levels and outcomes in a cohort of pediatric ARDS; 2) determine the composition of the pathogenic nucleosomes by identifying specific histones and associated post-translational modifications; 3) demonstrate the pathogenicity of post-translationally modified and unmodified histones in in vitro cell culture and in vivo rodent models; and 4) develop the skills necessary to become a successful translational scientist in pediatric lung injury by focused training in epidemiology and proteomics. The proposed studies leverage existing infrastructure at the Children’s Hospital of Philadelphia and University of Pennsylvania to conduct a cohort study in pediatric ARDS and to perform novel proteomic analyses. A diverse and experienced mentorship team, with expertise in basic, translational, and clinical research, has been assembled to provide guidance through a rigorous training plan involving research conduct, didactics in advanced epidemiological analyses and proteomics, and intensive mentorship. The proposed studies will establish the relevance of plasma nucleosomes in pediatric ARDS, provide a novel technique for isolating and analyzing nucleosome-associated proteins, and improve our understanding of the pathogenicity of circulating histones. We will use these insights to study novel therapies for ARDS, and I will gain the necessary training in clinical research and proteomics to mature into an independent translational scientist working to improve outcomes for critically ill children.