线粒体ROS与NLRP3炎性小体对话：消退素D1治疗急性肺损伤的靶标

Currently， acute lung injury is one of the most severe diseases with no satisfactory therapeutic strategies in clinic . Emerging evidence demonstrated that resolvin D1 can inhibit lung inflammation and attenuate acute lung injury in mice. However, the lung protective mechanism of resolvin D1 is still elusive. Recent studies suggested that both NLRP3 inflammasome and oxidative stress contribute to the lung injury. Mitochondrial oxidative stress and NLRP3 inflammasome could activate each other in other disease model. Our preliminary data also showed that NLRP3 was elevated in the lung tissue of LPS-induced ALI animals, which can be blocked by resolvin D1. Therefore, we hypothesized that a pathogenic cross talk between mitochondrial ROS and NLRP3 inflammasome may exist in the lung of ALI and serve as the therapeutic target of resolvin D1 in lung protection. In the present proposal, employing the in vitro cells and animals subjected to the ALI-related challenges, we will explore the existence and contribution of a crosstalk between mitochondrial ROS and NLRP3 inflammasome in ALI, as well as the effect of resolvin D1 therapy on this crosstalk, which will significantly gain our understanding on the pathogenesis of ALI and resolvin D1 therapy.

急性肺损伤（ALI）是威胁危重症患者生命及生存质量的临床重症之一，目前尚缺乏满意的治疗手段。研究发现消退素D1可以减轻ALI小鼠的炎症反应及肺损伤。但消退素D1肺保护作用的具体机制尚不明确。近期研究表明，NLRP3炎性小体活化及氧化应激参与了疾病的发生和发展；线粒体氧化应激可以激活NLRP3炎性小体，而炎症可以诱导线粒体功能障碍；我们的预实验结果也显示，NLRP3在LPS诱导的ALI肺组织显著增加，消退素D1可以显著抑制NLRP3的上调。因此，我们推测：在ALI中可能存在线粒体氧化应激与NLRP3炎性小体之间的病理性对话，消退素D1可能通过打断这一病理性对话而起到了肺保护作用。本研究将在细胞及动物水平探讨ALI过程中线粒体氧化应激与NLRP3炎性小体之间的病理性对话及消退素D1对它的影响，为深入理解ALI的病理机制及消退素D1的治疗靶点提供新视点。

一、急性肺损伤（ALI）是威胁危重症患者生命及生存质量的临床重症之一，目前尚缺乏满意的治疗手段。研究发现消退素D1（RvD1）可减轻ALI小鼠的炎症反应及肺损伤，但其具体机制尚不明确。已知NLRP3炎性小体活化及氧化应激参与疾病的发生发展。因此，本研究探讨RvD1对ALI小鼠肺部炎症反应和NLRP3炎性小体的影响。实验采用RvD1预处理小鼠，给予LPS 诱导ALI，观察NLRP3 炎性小体活化及肺损伤情况。结果：LPS刺激后，小鼠肺组织出现病理损伤，IL-18、IL-1β含量均较正常对照组显著升高（P<0.05），肺组织NLRP3、ASC、caspase-1表达较对照组显著升高（P<0.05）。给予RvD1预处理后，肺组织病理损伤减轻，IL-18、IL-1β含量显著降低（P<0.05）；NLRP3、ASC及caspase-1表达较LPS组显著降低（P<0.05）。本研究明确RvD1具有肺保护作用，其通过抑制NLRP3炎性小体通路激活减轻肺损伤程度。.二、缺氧诱导因子（HIF）在缺氧状态下可调控多种基因表达，以增加机体对缺氧的耐受力。脯氨酰羟化酶（PHD）可抑制HIF-1α的稳定表达。抑制PHD已成为相关疾病治疗的新策略之一。FG-4592是一种口服PHD抑制剂，主要用于肾性贫血治疗，其是否可用于ALI治疗目前无文献报道。本试验分别给以FG-4592和2-DG（糖酵解抑制剂）预处理小鼠，LPS诱导ALI模型建立，观察肺组织病理改变、丙酮酸脱氢酶、髓过氧化物酶酶、SDH、COX IV等表达变化。结果：与对照组相比，ALI小鼠肺组织炎症改变明显，BALF中TNF-α、IL-6和IL-1β表达水平升高（P<0.05），ROS和MPO水平显著增高，PDH活性和ATP含量显著降低（P<0.05）。FG-4592治疗后，肺部病理损伤明显改善，BALF中TNF-α、IL-6和IL-1β表达水平显著降低，ROS和MPO水平显著降低，PDH和ATP含量显著升高。而2-DG给药显著抑制FG-4592肺保护作用。本部分实验明确FG-4592具有肺保护作用。其通过稳定HIF-1α，增加糖酵解和三羧酸循环，优化线粒体功能，减少ROS积累实现肺保护作用。