基于蛋白质组学技术研究irisin对脓毒症大鼠肝脏线粒体的保护作用机制

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Yet, no agent has convincingly proven to be consistently efficacious in clinical trials. Liver is one of the major organs easily being damaged and involved by sepsis, while accumulating studies have shown that mitochondria are important targets of injury during sepsis. Herein, it has great significance to seek new drugs and therapeutic targets and protect the liver mitochondrial function for the treatment of sepsis. Irisin has also been demonstrated to reduce oxidative stresses and protect mitochondrial function in cardiomyocytes. However, the relationship between irisin and sepsis remains unknown. . Our previous research has showed that serum irisin level in sepsis patients and septic rats were both decreased, sepsis-induced liver mitochondrial damage in septic rats could be ameliorated obviously after exogenous irisin- supplyment .In this proposal, we plan to use a cecal ligature and puncture (CLP) model of rats to investigate the changes of liver mitochondrial protein expression after irisin treatment, using TMT-based proteomic techniques. Furthermore, we will analyze the proteomic data to seek the key proteins and signaling pathway in the protective effect of irisin on mitochondria, reveal the molecular mechanism that involved in the protective effect on sepsis-induced liver mitochondrial damage and find the potential therapeutic targets which participated in sepsis-induced liver mitochondrial damage. The present study can provide a new insights and theoretical basis for the clinical treatment of sepsis-induced liver damage.

脓毒症是临床上常见的危重症疾病，迄今尚无有效的治疗方法。肝脏是脓毒症病理进程中最容易被攻击的重要器官，而线粒体是脓毒症损伤的重要的靶标，因此寻求新的治疗药物和治疗靶点，保护肝脏线粒体功能对于治疗脓毒症具有重大意义。研究发现irisin具有降低机体氧化应激和保护心肌细胞线粒体功能的作用，而目前并未有其在脓毒症中的研究。我们前期工作发现irisin在脓毒症临床患者和脓毒症大鼠血清中表达降低，而外源性给予irisin则可以明显减轻大鼠脓毒症诱导的肝脏线粒体损伤。因此，本项目拟以CLP脓毒症大鼠为研究对象，采用TMT定量蛋白质组学技术研究irisin治疗前后肝脏线粒体蛋白的表达差异，寻找参与irisin对线粒体保护作用的关键蛋白和信号通路，揭示irisin对肝脏线粒体保护作用的分子机制以及参与脓毒症肝脏线粒体损伤的潜在治疗靶点，本研究将为临床治疗脓毒症诱导的肝脏损伤提供有效的方案和理论依据。

脓毒症是导致住院死亡的重要病因，迄今尚无有效的治疗方法。肝脏是脓毒症病理进程中最先被攻击的重要器官，而线粒体功能紊乱与脓毒症诱导的多器官功能障碍密切相关，临床研究表明针对线粒体的治疗方案可以提高脓毒症患者的预后。铁死亡是一种依赖铁离子的程序性细胞死亡，被报道可能是脓毒症新的病理机制，且与线粒体功能密切相关。铁死亡与脓毒症诱导的肝脏损伤之间的关系以及irisin 在其中可能发挥的作用尚不清楚。本研究中首先检测了临床脓毒症患者血清irisin水平，随后建立CLP脓毒症小鼠模型，探索外源性irisin处理对肝脏铁死亡以及线粒体功能的影响。研究结果发现，发现脓毒症患者血清中 irisin 的含量显著低于健康志愿者，且与APACHE II评分呈负相关。外源性irisin处理CLP脓毒症小鼠可抑制铁死亡，减轻炎症反应，降低氧化应激水平，改善异常的线粒体形态等。同时使用LPS处理肝脏细胞模拟脓毒症，验证irisin对铁死亡的抑制作用。当与铁死亡负相关的重要蛋白GPX4被抑制后，irisin对LPS处理肝脏细胞以及CLP脓毒症小鼠的保护作用也被削弱。.上述结果揭示血清irisin与脓毒症患者病情的严重度呈负相关，脓毒症实验中irisin可抑制铁死亡，改善线粒体功能。因此，irisin在脓毒症的治疗中具有一定的潜能。.