Crosstalk between mitochondrial permeability transition and ETC supercomplexes in myocardial infarction

心肌梗死中线粒体通透性转变与 ETC 超复合物之间的串扰

• 批准号: 9207161
• 负责人: Sabzali Javadov
• 金额: $ 36.28万
• 依托单位: UNIVERSITY OF PUERTO RICO MED SCIENCES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-22 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9207161
• 关键词: ATP Synthesis Pathway; Accounting; Acute myocardial infarction; Animal Model; Calcium; Cardiac; Cardiac Myocytes; Cardiolipins; Cell Death; Cell Survival; Cessation of life; Clinical; Complex; Coronary artery; Coronary heart disease; Development; Diffusion; Dissociation; Electron Transport; Electrons; Energy Metabolism; Extravasation; Heart; In Vitro; Individual; Injury; Inner mitochondrial membrane; Ischemia; Knowledge; Ligation; Mediating; Mitochondria; Mitochondrial Swelling; Modeling; Molecular; Morbidity - disease rate; Mus; Myocardial Infarction; Myocardial Ischemia; Myocardial dysfunction; Organelles; Outcome; Oxidative Phosphorylation; Oxidative Stress; Oxides; Pathogenesis; Pathologic; Patients; Permeability; Phospholipids; Play; Production; Rattus; Reactive Oxygen Species; Reperfusion Injury; Reperfusion Therapy; Role; Therapeutic Intervention; Time; Treatment Efficacy; United States; coronary perfusion; effective therapy; improved; in vivo; inhibitor/antagonist; inorganic phosphate; insight; knock-down; mitochondrial permeability transition pore; mortality; novel therapeutic intervention; oxidation; prevent; response; restoration; sanglifehrin A; solid state; targeted treatment; tert-Butylhydroperoxide

ABSRACT Coronary heart disease is the leading cause of morbidity and mortality worldwide. Timely restoration of coronary perfusion known as reperfusion is the only effective therapeutic intervention for protecting the heart from myocardial infarction (MI). Currently, there is no effective therapy for preventing cardiac ischemia-reperfusion (IR) injury. The loss of mitochondrial function plays a crucial role in IR-induced cell death suggesting that protection and restoration of mitochondrial function is pivotal to cell survival in the heart. However, limited knowledge of the mechanisms underlying mitochondria-mediated cell death obscures the development of new mitochondria-targeted cardioprotective compounds. Cardiac IR increases calcium, reactive oxygen species (ROS), and inorganic phosphate levels in mitochondria that induce mitochondrial permeability transition (MPT) concurrently with opening of the non-specific pathological MPT pores in the inner mitochondrial membrane. High mitochondrial ROS (mtROS) also may disintegrate mitochondrial supercomplexes (SCs), predominantly due to oxidation of cardiolipin (CL), a unique mitochondrial phospholipid. SCs are large supramolecular complexes containing individual electron transport chain (ETC) complexes. According to the solid-state model, the assembly of SCs provides high-efficiency electron flux throughout the ETC; it increases ATP synthesis and significantly reduces electron leakage and mtROS production due to short diffusion distances between ETC complexes. The cause-and-effect relationship between MPT induction and SC degradation has not yet been established. We hypothesize that the MPT plays a causal role in the disintegration of mitochondrial SCs, leading to diminished energy metabolism and cell death in cardiac IR. We propose that MPT-induced mitochondrial swelling sensitizes CL to the ROS attack leading to degradation of SCs. The Specific Aims are as follows: (1) Determine the timing of MPT, disintegration of SCs and progression of post-MI injury. We will investigate the association between MPT pore opening and SC degradation, with progression of IR injury, using the animal model of in vivo MI induced by coronary artery ligation with/without subsequent reperfusion. We will also subject WT and tafazzin knockdown (TazKD) mice to cardiac IR to distinguish changes in SC assembling induced by CL oxidation versus CL deficiency. (2) Examine the cause-and-effect relationship between the MPT induction and SC disintegration in response to oxidative stress. We will subject cardiomyocytes/mitochondria with CyP-D (Ppif) and/or tafazzin deficiency to oxidative stress to clarify a cause-and-effect relationship between MPT and SC disintegration. In addition, cardiac mitochondria will be treated with oxidized CL in the presence of MPT inducers/blockers to reveal a causal role of MPT versus CL oxidation in SC degradation. (3) Define if inhibition of MPT, and mtROS scavenging protect synergistically against post-MI injury. These studies will establish whether combined therapy simultaneously targeting mtROS and MPT exerts synergistic cardioprotective effects on cardiac IR. The MPT inhibitor will be administered alone or in combination with mtROS scavengers during in vivo cardiac IR. In addition, WT and TazKD hearts will be subjected to ex vivo IR in the presence of the MPT inhibitor and/or mtROS scavengers. Overall, elucidating the crosstalk mechanisms between MPT and SC degradation will provide new insights into the molecular basis of mitochondria-mediated cell death during cardiac IR. The outcome of this project will allow development of new therapeutic strategies to prevent myocardial IR injury, and improve clinical consequences in patients with acute myocardial infarction through targeting mitochondria.

弃 冠心病是全球发病率和死亡率的主要原因。及时修复冠状动脉 被称为再灌注的灌注是保护心脏免受心脏的唯一有效的治疗干预措施 心肌梗塞（MI）。目前，没有有效的疗法来预防心脏缺血再灌注 （IR）受伤。线粒体功能的丧失在IR诱导的细胞死亡中起着至关重要的作用，这表明 线粒体功能的保护和恢复与心脏中细胞存活至关重要。但是，有限 了解线粒体介导的细胞死亡的机制的知识掩盖了新的发展 线粒体靶向心脏保护化合物。心脏IR增加钙，活性氧 线粒体中（ROS）和无机磷酸盐水平诱导线粒体通透性转变（MPT） 同时与内部线粒体膜中非特异性病理MPT孔的打开。高的 线粒体ROS（MTROS）也可能崩解线粒体超复合物（SC），主要是由于 心磷脂（CL）的氧化，一种独特的线粒体磷脂。 SC是大分子大分子复合物 包含单个电子传输链（ETC）复合物。根据固态模型，组装 SC的范围内提供了高效率的电子通量；它增加了ATP的合成，并显着 由于ETC复合物之间的短扩散距离，减少了电子泄漏和MTROS的产生。这 MPT诱导与SC降解之间的因果关系尚未建立。我们 假设MPT在线粒体SC的瓦解中起因果作用，导致减少 心脏IR的能量代谢和细胞死亡。我们建议MPT引起的线粒体肿胀敏感 CL到ROS攻击导致SC降解。具体目的如下：（1）确定 MPT的时机，SC的崩解和MI后损伤的进展。我们将调查协会 使用体内动物模型，在MPT孔口开口和SC降解以及IR损伤的进展之间 由冠状动脉连接诱导的MI，没有/没有随后再灌注。我们还将受到WT和Tafazzin 敲低（TAZKD）小鼠到心脏IR，以区分CL氧化引起的SC组装变化与 CL缺乏。 （2）检查MPT诱导与SC崩解之间的因果关系 响应氧化应激。我们将对心肌细胞/线粒体进行CYP-D（PPIF）和/或Tafazzin的对象。 缺乏氧化应激，以阐明MPT和SC崩解之间的因果关系。在 此外，在MPT诱导剂/阻滞剂存在下，将用氧化CL处理心脏线粒体以揭示 MPT与CL氧化在SC降解中的因果作用。 （3）定义是否抑制MPT和MTROS 清除协同防止MI后伤害。这些研究将确定是否合并治疗 同时针对MTRO和MPT对心脏IR发挥协同的心脏保护作用。 MPT 在体内心脏IR期间，抑制剂将单独或与MTROS清除剂结合使用。在 此外，在MPT抑制剂和/或MTRO的存在下，WT和TAZKD心脏将受到离体IR 清道夫。总体而言，阐明MPT和SC降解之间的串扰机制将提供新的 对心脏IR期间线粒体介导的细胞死亡的分子基础的见解。结果的结果 项目将允许制定新的治疗策略来预防心肌损伤，并改善临床 通过靶向线粒体的急性心肌梗塞患者的后果。