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.

摘要 冠心病是全世界发病和死亡的主要原因。冠状动脉及时恢复 灌注（称为再灌注）是保护心脏免受损害的唯一有效的治疗干预措施。 心肌梗塞（MI）。目前尚无有效的治疗方法来预防心脏缺血再灌注 （红外）损伤。线粒体功能的丧失在红外线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对于心脏细胞的生存至关重要。然而，有限 对线粒体介导的细胞死亡机制的了解掩盖了新的开发 线粒体靶向心脏保护化合物。心脏 IR 增加钙、活性氧 （ROS）和线粒体中诱导线粒体通透性转变（MPT）的无机磷酸盐水平 同时打开线粒体内膜中的非特异性病理性 MPT 孔。高的 线粒体 ROS (mtROS) 也可能分解线粒体超复合物 (SC)，主要是由于 心磷脂（CL）的氧化，一种独特的线粒体磷脂。 SC 是大型超分子复合物 包含单独的电子传输链（ETC）复合物。根据固态模型，组装 SC 为整个 ETC 提供高效电子通量；它增加 ATP 合成并显着 由于 ETC 复合物之间的扩散距离短，减少了电子泄漏和 mtROS 的产生。这 MPT诱导和SC降解之间的因果关系尚未建立。我们 假设 MPT 在线粒体 SC 的崩解中发挥因果作用，导致线粒体 SC 的减少 心脏 IR 中的能量代谢和细胞死亡。我们认为 MPT 诱导的线粒体肿胀致敏 CL 对 ROS 的攻击导致 SC 降解。具体目标如下： (1) 确定 MPT 的时机、SC 的崩解和 MI 后损伤的进展。我们将对协会进行调查 使用体内动物模型研究 MPT 孔开放和 SC 降解之间的关系，以及 IR 损伤的进展 由冠状动脉结扎引起的 MI，有/没有随后的再灌注。我们还将对 WT 和 tafazzin 进行主题 敲低 (TazKD) 小鼠心脏 IR 来区分 CL 氧化诱导的 SC 组装变化与 CL 缺乏。 (2)考察MPT诱导与SC崩解之间的因果关系 响应氧化应激。我们将用 CyP-D (Ppif) 和/或 tafazzin 处理心肌细胞/线粒体 缺乏氧化应激来阐明 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 清除可协同保护心肌梗死后损伤。这些研究将确定联合治疗是否 同时靶向 mtROS 和 MPT 对心脏 IR 发挥协同心脏保护作用。 MPT 在体内心脏IR期间，抑制剂将单独施用或与mtROS清除剂组合施用。在 此外，WT 和 TazKD 心脏将在 MPT 抑制剂和/或 mtROS 存在的情况下进行离体 IR 拾荒者。总的来说，阐明 MPT 和 SC 退化之间的串扰机制将为我们提供新的思路。 深入了解心脏 IR 期间线粒体介导的细胞死亡的分子基础。这件事的结果 该项目将允许开发新的治疗策略来预防心肌 IR 损伤，并改善临床 通过靶向线粒体对急性心肌梗塞患者产生的后果。