Targeting the Thromboinflammatory Response to Mitigate Bowel Injury in Necrotizing Enterocolitis

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.