The Role of Extracellular Histones and Neutrophil Extracellular traps in Necrotizing Enterocolitis

项目摘要 坏死性小肠结肠炎(NEC)是新生儿期最常见的外科急症。尽管 在过去的三十年里，NEC在医疗保健、死亡率和发病率方面的进步没有改变。 这在很大程度上是由于对这种多因素疾病的复杂发病机制缺乏了解，以及 缺乏特定的治疗方法。 我们有初步数据显示，在早产儿中，组蛋白-DNA复合体升高 NEC。我们实验室和其他实验室的研究发现，细胞外组蛋白是许多病理变化的主要介质 病症包括败血症、血栓形成和创伤。在人类和动物败血症模型中，高水平的 组蛋白-DNA与器官衰竭和死亡率相关。此外，用特定抗体抑制组蛋白 降低内毒素和/或大肠杆菌攻击动物的死亡率，防止缺血再灌注和内毒素 导致急性肾损伤和血小板减少症。所有这些数据表明，组蛋白是相关的生物标志物 以及涉及组织坏死和炎症的病理条件下的治疗靶点。 组蛋白被凋亡或坏死的细胞被动地释放到细胞外环境中， 或主动作为中性粒细胞胞外陷阱(Net)。网络形成是细胞死亡的一种新范式，其中 中性粒细胞对感染或其他刺激做出反应，释放其核内容物。尽管篮网协助诱捕 细菌和其他病原体，它们的长期存在可能会导致邻近组织的损伤。我们有数据 显示NEC早产儿肠道组织中存在Net。无论篮网和他们的球队 NEC中的成分，特别是组蛋白，对肠道损伤和疾病进展的作用尚不清楚。 因此，在这项建议中，我们的目标是通过(I)确定组蛋白和Net在NEC病理中的作用 组蛋白-DNA水平是否是早产儿NEC预后不良的生物标志物；(Ii)特征 组蛋白在NEC小鼠模型中的释放和网状结构的形成，以及(Iii)研究组蛋白的作用 在实验性NEC中使用药理学和遗传学方法的抑制剂和网络形成。 总之，这个项目可能会促进我们对NEC的理解，描述新的生物标记物，以及 为这种高度致命的疾病带来新的治疗策略。

Project Summary Necrotizing enterocolitis (NEC) is the most common surgical emergency in the neonatal period. Despite advances in medical care, mortality and morbidity caused by NEC has not changed in the past three decades. This is largely due to a poor understanding of the complex pathogenesis of this multifactorial diseases and by the lack of specific therapies. We have preliminary data showing the histones-DNA complexes are elevated in premature infants with NEC. Studies from our lab and others identified extracellular histones as major mediators in many pathological conditions including sepsis, thrombosis, and trauma. In humans and animal models of sepsis, high levels of histones-DNA correlate with organ failure and mortality. Moreover, histone inhibition with specific antibodies reduces mortality in LPS- and/or E.coli challenged animals, prevents ischemia-reperfusion and endotoxin induced acute kidney injury, and thrombocytopenia. All these data suggest that histones are relevant biomarkers and therapeutic targets in pathologic conditions that involve tissue necrosis and inflammation. Histones are released into the extracellular environment either passively by apoptotic or necrotic cells, or actively as neutrophil extracellular traps (NETs). NETs formation is a new paradigm of cell death where neutrophils release their nuclear contents in response to infection or other stimuli. Although NETs aid in trapping bacteria and other pathogens, their prolonged presence may lead to adjacent tissue damage. We have data showing the presence of NETs in intestinal tissue of premature infants with NEC. Whether NETs and their components, specifically histones, contribute to intestinal injury and disease progression in NEC is still unknown. Thus we aim in this proposal to investigate the role of histones and NETs in NEC pathology by (i) determining whether histones-DNA levels are biomarkers of poor prognosis in premature infants with NEC; (ii) characterizing histones' release and NETs formation in mouse models of NEC, and (iii) investigating the effects of histones inhibitors and NET formation using pharmacological and genetic approaches in experimental NEC. Over all this project will potentially advance our understanding of NEC, describe new biomarkers, and lead to novel therapeutic strategies for this highly lethal disease.