Loss of Endothelial S1PR1 Drives Post-Influenza Pulmonary Fibrosis

项目摘要 流感和冠状病毒等呼吸道病毒感染是导致急性呼吸窘迫的常见原因。 综合征(ARDS)，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重症患者仍然很常见，以及 许多病例因肺纤维化的发展而变得复杂。病毒感染后的肺纤维化可导致 因呼吸功能障碍、运动不耐受和短促等致残症状而导致的慢性残疾 呼吸和咳嗽。内皮损伤和功能障碍与ARDS的严重程度、肺的持久性有关 损伤和失调的组织修复。目前还没有预防病毒后感染的治疗方法。 肺纤维化，事实上，支持性机械通气可能会进一步使病理性内皮细胞永久化 损伤和加重纤维化的结果。 神经鞘氨醇-1-磷酸(S1P)-S1P受体1(S1PR1)信号轴是内皮细胞(EC)信号转导的关键 内皮功能的调节剂，包括对血管通透性的调节作用。然而，它的作用是 S1PR1在ARDS所致的肺病毒感染的纤维增殖期的作用尚未得到很好的研究。 具体地说，EC和肺成纤维细胞之间的相互作用是肺疾病发生发展中的关键效应细胞。 由于它们产生细胞外基质以及收缩和扭曲组织的能力而导致的纤维化 架构，还没有被定义。逆转内皮功能障碍，恢复肺血管完整性 通过病毒感染后EC S1PR1的增强，可能通过预防 病毒后肺纤维化的发展。 我们的初步结果表明，在甲型流感期间，内皮细胞S1PR1的持续丢失是有害的 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感染导致肺损伤导致EC S1PR1丢失，导致EC成纤维细胞改变 会导致纤维化的串扰。此外，我们还建议在此背景下增强EC S1PR1的表达 IAV感染的研究将导致一种新的抗纤维化策略的发展。我们将使用内皮比增益- 在IAV感染模型中确定IAV感染如何驱动持续的功能缺失和功能丧失的小鼠 EC S1PR1的减少(目标1)，EC S1PR1如何影响转录信号和与成纤维细胞的串扰 在IAV感染后(目标2)，以及如何以治疗的方式使用EC S1PR1的增强来预防 IAV后肺纤维化(AIM 3)。更好地了解EC的分子机制和后遗症 IAV后的功能障碍及其对后续纤维增殖的影响将导致新的治疗方法来预防 肺部病毒感染的这种令人衰弱的并发症。

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.