目的:治疗性低温(MTH)是围手术期防治心肌缺血再灌注损伤(MIRI)的重要方法。在蛋白质翻译后修饰线粒体蛋白以调节线粒体功能是改善心肌缺血再灌注损伤的机制之一。本研究探讨了浅低温治疗改善心肌缺血再灌注损伤与COX10的O-GlcNAcylation水平之间的关系。
方法:我们使用体内Langendorff模型和体外缺氧/复氧(H/R)细胞模型来研究MTH对心肌缺血再灌注损伤的影响。组织学变化,心肌酶,氧化应激,和线粒体结构/功能进行评估。机理研究涉及各种分子生物学方法,如ELISA,免疫沉淀(IP),WB,和免疫荧光。
结果:我们的研究结果表明,MTH上调了COX10的O-GlcNAC化水平,改善了线粒体功能,抑制ROS的表达,改善心肌缺血再灌注损伤。在体内,MTH能有效缓解缺血再灌注引起的心功能不全,心肌损伤,线粒体损伤,和氧化还原失衡。体外,OGT抑制剂ALX抑制OGT介导的O-GlcNA酰化信号通路,下调COX10的O-Glc酰化水平,促进ROS释放,并抵消了MTH的保护作用。相反,OGA抑制剂ThG显示出与ALX相反的作用,进一步证实MTH激活OGT介导的O-GlcNAcylation信号通路发挥心脏保护作用。
结论:总之,MTH激活OGT介导的O-糖基化修饰的COX10调节线粒体功能,改善心肌缺血再灌注损伤,为MTH的临床应用提供了重要的理论依据。
OBJECTIVE: Mild therapeutic hypothermia (MTH) is an important method for perioperative prevention and treatment of myocardial ischemia-reperfusion injury (MIRI). Modifying mitochondrial proteins after protein translation to regulate mitochondrial function is one of the mechanisms for improving myocardial ischemia-reperfusion injury. This study investigated the relationship between shallow hypothermia treatment improving myocardial ischemia-reperfusion injury and the O-GlcNAcylation level of COX10.
METHODS: We used in vivo Langendorff model and in vitro hypoxia/reoxygenation (H/R) cell model to investigate the effects of MTH on myocardial ischemia-reperfusion injury. Histological changes, myocardial enzymes, oxidative stress, and mitochondrial structure/function were assessed. Mechanistic studies involved various molecular biology methods such as ELISA, immunoprecipitation (IP), WB, and immunofluorescence.
RESULTS: Our research results indicate that MTH upregulates the O-GlcNACylation level of COX10, improves mitochondrial function, and inhibits the expression of ROS to improve myocardial ischemia-reperfusion injury. In vivo, MTH effectively alleviates ischemia-reperfusion induced cardiac dysfunction, myocardial injury, mitochondrial damage, and redox imbalance. In vitro, the
OGT inhibitor ALX inhibits the
OGT mediated O-GlcNA acylation signaling pathway, downregulates the O-Glc acylation level of COX10, promotes ROS release, and counteracts the protective effect of MTH. On the contrary, the OGA inhibitor ThG showed opposite effects to ALX, further confirming that MTH activated the
OGT mediated O-GlcNAcylation signaling pathway to exert cardioprotective effects.
CONCLUSIONS: In summary, MTH activates
OGT mediated O-glycosylation modified COX10 to regulate mitochondrial function and improve myocardial ischemia-reperfusion injury, which provides important theoretical basis for the clinical application of MTH.