Targeting the Thromboinflammatory Response to Mitigate Bowel Injury in Necrotizing Enterocolitis

坏死性小肠结肠炎（NEC）是一种影响早产儿的毁灭性疾病，可导致广泛的 肠坏死和穿孔最严重的形式与高发病率和死亡率有关， 幸存者有严重神经功能缺损的风险。可悲的是，在改善 结果，这部分是由于其多因素发病机制，包括肠屏障的不成熟， 缺血性组织损伤和继发于免疫系统不成熟的过度炎症。此外还有 有证据表明血小板（内源性和输注的）有助于NEC病理学。 这项研究的目的是检验血小板-血管性血友病因子（VWF）轴 并且其在血栓炎症中的作用有助于NEC的发生/进展。为支持这一 前提是初步结果表明：（i）VWF的缺乏可以保护新生小鼠免于发育 NEC;（ii）ADAMTS 13（一种切割VWF从而限制血栓大小的蛋白酶）的基因缺失， 疾病严重程度;和（iii）将血库储存的人血小板给予遗传修饰的新生儿 支持人而非小鼠血小板介导的血栓形成的小鼠导致组织损伤增加，增强 细菌入侵，局部免疫活性细胞群的改变，甚至在NEC时死亡， 诱导条件。然而，有助于这些观察的特定分子机制和 在此过程中是否涉及其它血小板粘附和信号传导途径在很大程度上是未知的。 基于我们对血小板-VWF轴支持止血和血栓形成的广泛了解，我们现在将 确定其在NEC发展和进步中的作用。这将涉及使用转基因 动物，新的活体模型，通过FACs和单细胞评估肠道免疫细胞群 基因组分析，独特的生物制剂和小分子，将进一步了解途径和潜力 治疗假设将在三个目标中进行检验：在目标1中，我们将进一步阐明VWF在NEC中的作用， 重点关注血小板结合区（A1结构域），以及关键的血小板粘附和信号通路 通过使用转基因动物模型。基于这些结果，目标2将评估新的药理学 在经历NEC诱导的新生小鼠中靶向血小板-VWF轴的药剂。在目标3中，我们将测试 假设血库储存的人血小板可导致输血引起的肠损伤， 来源于脐带血的那些低血栓形成的性质可能是保护性的。 拟议的研究将通过定义血小板是如何- VWF轴及其在血栓-炎症中的作用有助于NEC中的组织损伤。这也将导致 开发新的或FDA批准的药物，可以重新利用，以减少 与这种毁灭性疾病相关的发病率和死亡率。

Necrotizing enterocolitis (NEC) is a devastating disease affecting premature infants that can result in extensive bowel necrosis and perforation. The most severe forms are associated with high morbidity and mortality with survivors at risk for significant neurological deficits. Sadly, little progress has been made towards improving outcomes, which is due in part to its multifactorial pathogenesis that includes immaturity of the intestinal barrier, ischemic tissue injury, and hyperinflammation secondary to immaturity of the immune system. In addition, there is evidence suggesting that platelets (both endogenous and transfused) contribute to NEC pathology. The goal of the proposed research is to test the hypothesis that the platelet-Von Willebrand Factor (VWF) axis and its role in thromboinflammation contributes to the development / progression of NEC. In support of this premise are preliminary results demonstrating that: (i) absence of VWF protects neonatal mice from developing NEC; (ii) genetic deletion of ADAMTS13, a protease that cleaves VWF thereby limiting thrombus size, augments disease severity; and (iii) administration of blood bank stored human platelets to genetically modified neonatal mice that support human but not mouse platelet mediated thrombosis results in increased tissue injury, enhanced bacterial invasion, alteration in local immunocompetent cell populations, and even death when subjected to NEC- inducing conditions. However, the specific molecular mechanisms that contribute to these observations and whether other platelet adhesion and signaling pathways are involved in this process are largely unknown. Based on our vast knowledge of the platelet-VWF axis in supporting hemostasis and thrombosis, we will now determine its role in the development and progression of NEC. This will involve the use of genetically modified animals, novel intravital models, assessment of intestinal immune cell populations by FACs and single cell genomic analyses, unique biologics and small molecules that will further inform on pathways and potential therapies. Hypotheses will be tested in three aims: In Aim 1, we will further delineate the role of VWF in NEC, with focus on the platelet binding region (A1 domain), as well as key platelet adhesion and signaling pathways by using genetically modified animal models. Based on these results, Aim 2 will evaluate novel pharmacologic agents that target the platelet-VWF axis in neonatal mice undergoing NEC induction. In Aim 3, we will test the hypothesis that blood bank stored human platelets can contribute to transfusion-induced bowel injury and that the hypothrombogenic nature of those derived from cord blood may be protective. The proposed studies will make a significant conceptual advancement in knowledge by defining how the platelet- VWF axis and its role in thrombo-inflammation contributes to tissue injury in NEC. It will also lead to the development of novel or identification of FDA approved pharmaceuticals that can be repurposed to reduce the morbidity and mortality associated with this devastating disease.