孤儿核受体ERRα在脓毒症急性肺损伤发生发展中的作用及机制

Acute lung injury, a frequent complication of sepsis, is associated with significant morbidity and mortality. However, there is currently no effective treatment for sepsis-induced acute lung injury. Exaggerated inflammatory response and vascular endothelial barrier dysfunction are important pathophysiological mechanisms of sepsis-induced acute lung injury. Previous studies suggested that orphan nuclear receptor estrogen related receptor α (ERRα) is a critical regulator of inflammatory response and may play an important role in modulation of vascular endothelial barrier function. Our preliminary experiment indicates that ERRα may play an important role in the development of sepsis-induced acute lung injury. However, there is no report as yet regarding the role and mechanism of ERRα in the development of sepsis-induced acute lung injury. The present project contains two parts. First, we will investigate the role and mechanism of ERRα in the development of acute lung injury in a murine model of sepsis induced by cecal ligation and puncture using ERRα knockout mice. Second, we will further explore the role and mechanism of ERRα in inflammation and endothelial barrier dysfunction using pulmonary microvascular endothelial cells isolated from ERRα knockout mice. The present project aims to identify the pathogenesis of sepsis-induced acute lung injury and explore new target for effectively preventing and treating sepsis-induced acute lung injury.

急性肺损伤是脓毒症的常见并发症，发病率和死亡率较高，但目前缺乏特异有效的治疗方法。失控性炎症反应和血管内皮屏障功能障碍是脓毒症急性肺损伤发生发展的重要病理生理机制。研究发现，孤儿核受体雌激素相关受体α（ERRα）是炎症反应的关键调节因子，并可能对血管内皮屏障功能具有重要调控作用。我们的前期研究结果初步提示ERRα对脓毒症急性肺损伤的发生发展具有重要影响。然而，目前尚无ERRα对脓毒症急性肺损伤的影响及其机制的研究报道。本项目研究分为两部分，第一部分将利用ERRα基因敲除小鼠研究ERRα对盲肠结扎穿孔诱导的脓毒症小鼠急性肺损伤的影响及其分子机制；第二部分将培养ERRα基因敲除小鼠肺微血管内皮细胞，运用分子生物学技术在细胞水平探讨ERRα对肺微血管内皮细胞炎症反应和屏障功能障碍的影响及其机制。本项目力图明确ERRα对脓毒症急性肺损伤的影响及其机制，为脓毒症急性肺损伤的防治提供新的治疗靶点。

在体内模型中，利用盲肠结扎穿刺诱导脓毒症大鼠的急性肺损伤模型。将动物随机分成正常组、假手术组、CLP模型组、以及ERRα抑制剂XCT-790组。给予XCT-790组能够明显加剧脓毒症诱导大鼠肺组织病理损伤、肺渗透性的增加、髓过氧化物酶的活性、血清中炎症因子以及肺泡灌洗液中炎症细胞的聚集。另外，XCT-790能够加剧CLP诱导的肺超氧化物歧化酶以及丙二醛水平的减少。在体内模型中，将大鼠肺微血管内皮细胞暴露于LPS中将会增加内皮细胞的通透性、减少紧密连接蛋白ZO-1、Occludin、JAMA-A和黏附蛋白VE-cadherin的表达，而基因敲低ERRα能够加剧LPS诱导的这些损伤。另外，抑制ERRα的表达能够加剧LPS够诱导炎症因子的产生，增加的磷酸化 IκBα和NF-κB p65的表达， 同时，敲除ERRα显著促进了LPS激活的线粒体活性氧的产生和LPS诱导的大鼠PMVECs Sirt3蛋白水平的下调。因此，本研究为ERRα在脓毒症大鼠ALI中发挥新的负调控作用提供了证据。且ERRα诱导效应的潜在机制很大程度上依赖于对炎症反应和氧化应激的调节。