Loss of Endothelial S1PR1 Drives Post-Influenza Pulmonary Fibrosis

项目摘要 呼吸道病毒感染如流感和冠状病毒是急性呼吸窘迫的常见原因 急性呼吸窘迫综合征（ARDS）是一种致残性疾病，死亡率高达46%。虽然支持性干预措施减少了 ARDS的总死亡率，需要长时间机械通气的严重病例仍然很常见， 许多病例由于肺纤维化的发展而变得复杂。病毒感染后肺纤维化可导致 由于呼吸功能障碍、运动不耐受和短粗等致残症状导致的慢性残疾 呼吸和咳嗽。内皮细胞损伤和功能障碍与ARDS的严重程度、肺功能的持续存在有关， 损伤和失调的组织修复。目前还没有治疗方法来预防病毒感染后的发展。 肺纤维化，事实上，支持性机械通气可能进一步使病理性内皮细胞 损伤和恶化纤维化结果。 内皮细胞（EC）上的鞘氨醇-1-磷酸（S1 P）-S1 P受体1（S1 PR 1）信号传导轴是一个关键， 内皮功能的调节剂，包括在血管通透性中的调节作用。但是，作用 S1 PR 1在肺病毒感染诱导的ARDS的纤维增生期尚未得到很好的探索。 具体而言，EC和肺成纤维细胞之间的串扰，肺成纤维细胞是肺成纤维细胞发展中的关键效应细胞。 由于它们产生细胞外基质以及它们收缩和扭曲组织的能力， 架构尚未定义。逆转内皮功能障碍和恢复肺血管完整性 通过增强病毒感染后的EC S1 PR 1， 病毒感染后肺纤维化的发展。 我们的初步结果表明，在甲型流感期间，内皮S1 PR 1的持续缺失是有害的。 病毒（IAV）感染，导致血管通透性增加和肺纤维化增加。我们 假设IAV感染诱导的肺损伤诱导EC S1 PR 1丢失，导致改变的EC成纤维细胞 导致纤维化的串扰。此外，我们提出，在这种情况下，增加EC S1 PR 1表达， IAV感染将导致一种新的抗纤维化策略的发展。我们将使用内皮细胞特异性增益- 在IAV感染模型中的功能丧失和功能丧失小鼠，以确定IAV感染如何驱动持续的 EC S1 PR 1的减少（目的1），EC S1 PR 1如何影响转录组特征和与成纤维细胞的串扰 IAV感染后（目的2），以及如何以治疗方式使用EC S1 PR 1增强，以预防 IAV后肺纤维化（目的3）。更好地了解EC的分子机制和后遗症 IAV后的功能障碍和对随后的纤维增生的影响将导致新的治疗方法，以防止 肺部病毒感染的并发症

Project Summary Respiratory viral infections such as influenza and coronaviruses are frequent causes of acute respiratory distress syndrome (ARDS), a disabling condition with a mortality up to 46%. While supportive interventions have reduced the overall mortality of ARDS, severe cases requiring prolonged mechanical ventilation remain common, and many cases are complicated by the development of fibrosis in the lung. Post-viral pulmonary fibrosis can lead to chronic disability due to respiratory dysfunction, exercise intolerance and disabling symptoms such as shortness of breath and cough. Endothelial injury and dysfunction contribute to the severity of ARDS, persistence of lung injury, and dysregulated tissue repair. Currently there are no therapies to prevent the development of post-viral pulmonary fibrosis, and in fact supportive mechanical ventilation may further perpetuate pathological endothelial injury and worsen fibrotic outcomes. The sphingosine-1-phosphate (S1P)-S1P receptor 1 (S1PR1) signaling axis on endothelial cells (EC) is a key modulator of endothelial function, including a regulatory role in vascular permeability. However, the role of S1PR1 during the fibroproliferative phase of pulmonary viral infection induced ARDS has not been well explored. Specifically, cross talk between EC and lung fibroblasts, key effector cells in the development of pulmonary fibrosis because of their production of extracellular matrix and their ability to contract and distort tissue architecture, has not been defined. Reversing endothelial dysfunction and restoring pulmonary vascular integrity via augmentation of EC S1PR1 after viral infection could have great therapeutic value by preventing the development of post-viral pulmonary fibrosis. Our preliminary results demonstrate that persistent loss of endothelial S1PR1 is deleterious during influenza A virus (IAV) infection, resulting in increased vascular permeability and increased pulmonary fibrosis. We hypothesize that IAV infection induced lung injury induces loss of EC S1PR1, leading to altered EC-fibroblast cross talk which drives fibrosis. Furthermore, we propose that augmenting EC S1PR1 expression in the context of IAV infection will lead to the development of a novel anti-fibrotic strategy. We will use endothelial specific gain- of-function and loss-of-function mice in an IAV infection model to determine how IAV infection drives sustained reduction of EC S1PR1 (Aim 1), how EC S1PR1 affects transcriptomic signatures and cross talk with fibroblasts after IAV infection (Aim 2), and how augmentation of EC S1PR1 can be used in a therapeutic manner to prevent post-IAV pulmonary fibrosis (Aim 3). A better understanding of the molecular mechanisms and sequelae of EC dysfunction after IAV and the effects on subsequent fibroproliferation will lead to novel therapeutics to prevent this debilitating complication of pulmonary viral infections.