Exosomal Gasdermin D Mediated Lung to Brain Crosswalk in Preterm Brain Injury

项目总结 以炎症性损伤和肺发育受损为特征的支气管肺发育不良(BPD)是 最常见的并发症是早产，也是神经发育不良的预测指标。 目前尚不清楚肺损伤在多大程度上导致这些患者的神经发育障碍(NDI) 早产儿。根据我们的初步数据，循环外切体起源于 患有严重BPD的早产儿在体外会导致神经干细胞(NSC)死亡，这项研究的主要目标是 建议确定这些循环外切体介导肺和脑的分子机制。 相声及其对脑损伤和NDI的贡献。了解这些机制对于 随着更多早产儿存活下来，公共卫生仍然没有有效的方法来治疗BPD或其 关联的NDI。上睑下垂是一种新描述的炎性细胞死亡形式，它完全由 Gasdermin D(GSDMD)，一种炎症体激活的膜“造孔”蛋白。外切体是纳米级的 大小的胞外小泡在器官间的通讯中起着关键作用。我们最近证明了 发生严重BPD的早产儿GSDMD和表面活性蛋白C(SPC)的表达增加， 肺泡II型上皮细胞(AEC)的标志，在其1周龄的循环外切体中。在临床前阶段 在BPD实验模型的研究中，从血清中分离出类似的含有GSDMD的外切体。 暴露在高氧环境下的新生大鼠。重要的是，通过将这些外切体转移到血液循环中 正常新生大鼠大脑发育受损。这些发现导致我们提出了一个新的模型，将 BPD、外体GSDMD与脑损伤。该模型的中心假设是含有GSDMD的 在BPD的进化阶段，外体从AEC释放到循环中，神经元摄取 这些外切体导致神经细胞下垂和NDI。这一假设将通过三个目标进行检验：Aim 1.研究血管内皮细胞来源的循环外切体中GSDMD表达谱之间的关系 早产儿BPD的严重程度。目的2.确定循环的机制功能 早产儿外显子在脑损伤和NDI中的作用目的3.阐明其分子机制 高氧通过刺激血管内皮细胞释放GSDMD+外切体，从而导致脑损伤和NDI。这些 研究将描绘一种新的外体GSDMD介导的肺到脑的串扰，它在 早产儿脑损伤与NDI的发病机制该项目的竣工将为 进一步探索针对胞外GSDMD的治疗干预措施以改善长期疗效 这些婴儿的呼吸和神经发育结果。这项建议与总体目标是一致的 NICHD和NHLBI的目标是通过尖端研究改善儿童健康，并将执行 由临床和基础呼吸系统研究、神经病理学和外周体学专家组成的团队 GSDMD生物学。

PROJECT SUMMARY Bronchopulmonary dysplasia (BPD), characterized by inflammatory injury and impaired lung development is the most common morbidity complicating preterm birth, and a predictor of poor neurodevelopmental outcomes. Currently it is unclear to what extent lung injury contributes to neurodevelopmental impairment (NDI) in these preterm infants. Based on our preliminary data which demonstrate that circulating exosomes derived from preterm infants who develop severe BPD induce neural stem cell (NSC) death in vitro, the major goal of this proposal is to determine the molecular mechanisms by which these circulating exosomes mediate lung to brain crosstalk and their contribution to brain injury and NDI. Understanding these mechanisms is fundamental to public health as more preterm infants are surviving, yet there remains no effective therapy for either BPD or its associated NDI. Pyroptosis is a newly described form of inflammatory cell death that is solely regulated by gasdermin D (GSDMD), an inflammasome-activated membrane “pore-forming” protein. Exosomes are nano- sized extracellular vesicles that play a key role in inter-organ communications. We recently demonstrated that preterm infants who develop severe BPD have increased expression of GSDMD and surfactant protein C (SPC), a marker of alveolar type II epithelial cells (AEC), in their circulating exosomes at 1 week of age. In preclinical studies with an experimental model of BPD, similar GSDMD-containing exosomes were isolated from the serum of newborn rats exposed to hyperoxia. Importantly, adoptive transfer of these exosomes into the circulation of normal newborn rats impaired brain development. These findings lead us to propose a novel model that links BPD, exosomal GSDMD and brain injury. The central hypothesis of this model is that GSDMD-containing exosomes are released from AEC into the circulation during the evolving stage of BPD, and neuronal uptake of these exosomes results in neural cell pyroptosis and NDI. This hypothesis will be tested through three aims: Aim 1. To characterize the relationship between GSDMD expression profiles in AEC-derived circulating exosomes and the severity of BPD in preterm infants. Aim 2. To determine the mechanistic functions of circulating exosomes from preterm infants in inducing brain injury and NDI. Aim 3. To elucidate the molecular mechanisms by which hyperoxia stimulates AEC to release GSDMD+ exosomes that induce brain injury and NDI. These studies will delineate a novel exosomal GSDMD-mediated lung to brain crosstalk that is critical in the pathogenesis of brain injury and NDI in premature infants. Completion of this project will provide a strong foundation to further explore therapeutic interventions that target exosomal GSDMD to improve long-term respiratory and neurodevelopment outcomes in these infants. This proposal is aligned with the overarching goal of the NICHD and NHLBI that is to improve children’s health through cutting edge research and it will be executed by a team approach with experts in clinical and basic respiratory research, neuropathology, and exosome and GSDMD biology.