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

项目摘要 以炎性损伤和肺发育受损为特征的支气管肺发育不良（BPD）是 最常见的并发早产的发病率，并预测不良的神经发育结果。 目前尚不清楚肺损伤在多大程度上导致这些儿童的神经发育障碍（NDI）。 早产儿基于我们的初步数据，这些数据表明，循环外泌体来源于 发展严重BPD的早产儿在体外诱导神经干细胞（NSC）死亡， 一项提议是确定这些循环外泌体介导肺到脑的分子机制 串扰及其对脑损伤和NDI的贡献。了解这些机制对于 公共卫生，因为更多的早产儿存活，但仍然没有有效的治疗BPD或其 相关NDI焦亡是一种新描述的炎性细胞死亡形式，其仅由 gasdermin D（GSDMD），一种炎性小体激活的膜“孔形成”蛋白。外泌体是纳米- 大小的细胞外囊泡，在器官间通讯中起着关键作用。我们最近证明， 患有严重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）的标志物，在1周龄时在其循环外泌体中。在临床前 在BPD实验模型的研究中，从血清中分离类似的含有GSDMD的外泌体 新生鼠暴露在高氧环境中的死亡率重要的是，这些外泌体过继转移到血液循环中， 正常新生大鼠大脑发育受损。这些发现使我们提出了一个新的模型， BPD，外泌体GSDMD和脑损伤。该模型的中心假设是， 在BPD的发展阶段，外泌体从AEC释放到循环中，并且神经元摄取外泌体。 这些外来体导致神经细胞焦亡和NDI。这一假设将通过三个目标进行检验： 1.表征AEC源性循环外泌体中GSDMD表达谱之间的关系 和早产儿BPD的严重程度。目标二。确定循环的机械功能 来自早产儿的外来体诱导脑损伤和NDI。目标3。为了阐明 高氧刺激AEC释放GSDMD+外泌体诱导脑损伤和NDI。这些 研究将描绘一种新的外泌体GSDMD介导的肺到脑的串扰， 早产儿脑损伤和NDI的发病机制。该项目的完成将提供一个强大的 进一步探索靶向外泌体GSDMD的治疗干预以改善长期生存的基础。 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， 通过与临床和基础呼吸研究、神经病理学和外泌体专家的团队合作， 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.