Irisin通过调控中性粒细胞线粒体Mg2+动力学抑制线粒体ROS诱导形成胞外陷阱从而拮抗脓毒症肺损伤的作用及机制研究

Irisin是可调节线粒体功能的新内源性肌肉因子。中性粒细胞（PMN）产生NETs是脓毒症肺损伤进展的核心机制，其线粒体功能障碍是NETs形成的关键机制。我们已发现Irisin保护心脏肥大，但不知其对脓毒症肺损伤的作用。预实验显示Irisin敲除加重脓毒症小鼠死亡和肺损伤、增加PMN浸润和NETs，Irisin过表达缓解这些病变。我们构建Irisin RESCUE的Irisin敲除小鼠，以盲肠结扎穿孔诱导脓毒症，LPS诱导原代小鼠骨髓来源PMN或HL-60类PMN发生NETs，探究Irisin拮抗脓毒症肺损伤的具体机制；利用荧光素酶报告系统、EMSA及ChIP等实验阐明Irisin通过其受体及受体后信号调节NF-κB，进而调控PMN线粒体镁离子（Mg2+）转运蛋白Mrs2的转录和表达，减低线粒体内Mg2+浓度缓解Mg2+过载和氧化应激，抑制NETs的形成，从而拮抗脓毒症肺损伤的创新机制。

Irisin is a new endogenous myokine that can regulate mitochondrial function. NETs derived from neutrophil (PMN) play a central role in the progression of septic lung injury, and PMNs’ mitochondrial dysfunction is the key mechanism for NETs formation. We've cognized that irisin protected cardiac hypertrophy, but knew nothing about its effect on septic lung injury. Our preparatory experiments showed that irisin deficiency aggravated mortality and lung injury in septic mice, accompanied with a significant increase in PMN infiltration and NETs formation in lung tissues, which were attenuated by irisin overexpression. Here, we try to reveal the specific mechanisms underlying the protection of irisin against septic lung injury. We will generate exogenous irisin-RESCUED mice with endogenous irisin knockout, and induce sepsis in them by using cecal ligation and puncture; and we will culture PMN derived from WT mouse bone marrow or HL-60, and induce NETs in them by exposing to LPS. We further perform luciferase reporter, EMSA and ChIP assays to elucidate whether irisin protects septic lung injury through a unique mechanism, in which irisin inhibit NETs formation induced by oxidative stress following Mg2+ overload stirred by LPS in mitochondria. We try to further identify that whether NF-κB, an inflammatory-related transcription factor, is inhibited by irisin through its special receptors and post-receptor signaling in PMN, and then the transcription and expression of Mrs2, an Mg2+ transporter in mitochondria, are suppressed by irisin-reduced transcription activity of NF-κB.