Mechanisms of platelet exosome-mediated acute chest syndrome in sickle cell disease

项目总结 急性胸腔综合征是一种急性肺损伤，是镰刀细胞死亡的主要原因之一。 疾病(SCD)。目前对急性冠脉综合征的治疗主要是支持性的，迫切需要抢救 可以阻止急性冠脉综合征进展的治疗方法。急性冠脉综合征通常是急性全身性血管闭塞危机的后遗症。 并在此之前出现了血小板减少症。然而，血小板在急性冠脉综合征发病机制中的作用在很大程度上仍然存在。 未知。我们推测急性冠脉综合征涉及NLRP3-炎症小体介导的携带IL-1β的血小板的释放 SCD中的外切体，促进血小板-中性粒细胞聚集，导致肺血流停止。我们也 提示靶向抑制血小板TLR4/NLRP3-caspase-1信号转导是治疗急性冠脉综合征的一种潜在方法。 为了验证这一假设，我们将使用一种综合生理学方法，该方法利用我们最近验证的模型 脂多糖诱导转基因SCD小鼠血管闭塞危象的体内多光子激发 (MPE)活体SCD小鼠肺血管成像，SCD人体血液流入的活细胞成像 体外微流控通道、血小板caspase-1缺失的SCD小鼠及其纳米粒子示踪分析 外显体。在目标1中，我们将确定携带IL-1β的血小板外切体在SCD中的释放是否促进 肺小动脉内的血小板-中性粒细胞聚集，导致肺内血流丧失。在目标2中，我们 将确定TLR4/NLRP3-炎症小体介导的血小板内caspase-1的激活是否与 用于从SCD患者的血小板中释放携带IL-1β的外切体。我们已经研制出以血小板为靶点的 纳米药物(PTN)，专门针对体内的血小板聚集和血栓形成部位进行靶向招募 药物递送。在目标3中，我们将确定PTNS是否携带TLR4或caspase-1抑制剂，或IL-1受体 白介素1受体拮抗剂(IL-1RA)可以选择性地募集到血小板聚集部位，阻断血小板外切体的释放和释放。 信号转导，并阻止SCD小鼠肺血管中的血小板-中性粒细胞聚集。这项研究将确定一个 新的，血小板衍生的外切体介导的促进急性冠脉综合征的机制。调查结果还将确定 将TLR4或caspase-1抑制剂或IL-1RA包裹在PTNS中可以成为一种潜在的救援疗法 伴有血管闭塞危象和血小板减少的高危SCD患者的急性冠脉综合征。

PROJECT SUMMARY Acute chest syndrome (ACS), a type of acute lung injury, is one of the leading causes of mortality in Sickle Cell Disease (SCD). Current treatments for ACS are primarily supportive, and there is a critical need for rescue therapies that can halt the progression of ACS. ACS is often a sequela of acute systemic vaso-occlusive crisis and preceded by thrombocytopenia. However, the role of platelets in the pathogenesis of ACS remains largely unknown. We hypothesize that ACS involves NLRP3-inflammasome mediated release of IL-1β-carrying platelet exosomes in SCD, which promote platelet-neutrophil aggregation leading to arrest of blood flow in lung. We also propose that targeted inhibition of TLR4/NLRP3-caspase-1 signaling in platelets is a potential therapy for ACS. To test this hypothesis, we will use an integrative physiologic approach that utilizes our recently validated model of lipopolysaccharide (LPS) induced vaso-occlusive crisis in transgenic SCD mice, in vivo multi-photon excitation (MPE) imaging of the lung vasculature in live SCD mice, live cell imaging of SCD human blood flowing in microfluidic channels in vitro, SCD mice lacking caspase-1 in platelets and nanoparticle tracking analyses of exosomes. In Aim 1, we will determine whether release of IL-1β-carrying platelet exosomes in SCD promote platelet-neutrophil aggregates in pulmonary arterioles that result in loss of blood flow in the lung. In Aim 2, we will determine whether TLR4/NLRP3-inflammasome mediated activation of caspase-1 in platelets is responsible for release of IL-1β-carrying exosomes from platelets in SCD. We have developed platelet-targeted nanomedicine (PTN) that specifically recruits to sites of platelet aggregation and thrombosis in vivo for targeted drug delivery. In Aim 3, we will determine whether PTNs carrying TLR4 or caspase-1 inhibitors, or IL-1 receptor antagonist (IL-1RA) can selectively recruit to sites of platelet aggregation to block platelet exosome release and signaling, and stop platelet-neutrophil aggregation in the lung vasculature of SCD mice. This study will identify a novel, platelet-derived exosome-mediated mechanism contributing to ACS. The findings will also establish that delivery of TLR4 or caspase-1 inhibitor, or IL-1RA encapsulated in PTNs can be a potential rescue therapy for ACS in high risk SCD patients presenting with vaso-occlusive crisis and thrombocytopenia.