Mitochondrial Ca-sensitive K channel-induced superoxide and cardiac protection

线粒体钙敏感钾通道诱导的超氧化物和心脏保护

• 批准号: 7759606
• 负责人: DAVID F STOWE
• 金额: $ 36.59万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7759606
• 关键词: Agonist; Anions; Apoptosis; Bioenergetics; Cardiac; Cardiac Myocytes; Cavia; Cells; Characteristics; Charge; Complement; Complex; Consumption; Coronary Arteriosclerosis; Coupled; Cytoprotection; Data; Drug Delivery Systems; Electron Transport; Electrons; Event; Exposure to; Feedback; Figs - dietary; Generations; Glutathione; Hand; Heart; Heart Atrium; Homeostasis; Hydrogen Peroxide; In Situ; Infarction; Inner mitochondrial membrane; Ischemia; Lead; Link; Lipid Bilayers; Mass Fragmentography; Mass Spectrum Analysis; Measures; Mechanics; Mediating; Membrane; Membrane Potentials; Memory; Metabolic; Mitochondria; Mitochondrial Matrix; Modeling; Molecular; Muscle Cells; NADH; Necrosis; Oxidation-Reduction; Pathway interactions; Patients; Peptides; Perfusion; Pharmaceutical Preparations; Phosphotransferases; Physiologic pulse; Play; Potassium Channel; Proteins; Proton Pump; Public Health; Reaction; Reactive Oxygen Species; Regulation; Reperfusion Injury; Reperfusion Therapy; Research; Respiration; Respiratory Chain; Role; Scheme; Source; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Stimulus; Superoxides; Swelling; Techniques; Testing; Tissues; Two-Dimensional Gel Electrophoresis; Vascular Smooth Muscle; Western Blotting; catalase; cell injury; cell type; conditioning; improved; improved functioning; indexing; inhibitor/antagonist; mimetics; novel strategies; practical application; preconditioning; protective effect; public health relevance; respiratory; skills; tool; voltage

DESCRIPTION (provided by applicant): Pharmacologic preconditioning (PPC) is an approach to limit ischemia reperfusion (IR) injury that does not require prior brief ischemia or the presence of the drug once ischemia occurs. KATP channel agonists, per se, induce PPC via memory pathways that lead to cardioprotection assessed by better tissue perfusion, improved metabolic and mechanical function, fewer dysrhythmias and reduced infarct size. Limits to our understanding of features and mechanisms of PPC have impeded optimal utilization of this potent phenomenon to protect against cardiac IR injury. Particularly lacking is an understanding of the role of the mitochondrion in PPC. Big (B) conductance Ca2+ -sensitive K+ channels (BKCa) are also present in cardiac cell inner mitochondrial membrane (IMM) and appear to mediate cardioprotection. We have evidence of protection also by small conductance (S) KCa channels in the IMM. We propose that drug -induced K+ entry into the mitochondrial (m) matrix alters bioenergetics in a way that increases electron leak to induce an increase in reactive oxygen species (ROS) required to trigger downstream protective effects. Preliminary results indicate that protective effects of mKCa channel opening are blocked by dismutation of the superoxide radical. A unifying hypothesis for the initiating mechanism of PPC may be a matrix K+ influx -induced ROS generation. We will a) examine in guinea pig isolated cardiac mitochondria the bioenergetic mechanisms initiated by matrix K+ influx that lead to ROS generation and b) determine the specific ROS responsible for triggering PPC in guinea pig isolated hearts. In addition we will c) identify these channels by Western blots, 2D gel electrophoresis and MALDI- TOF and LIT SNCE mass spectrometry and characterize these channels in artificial lipid bilayers. We will use the best techniques, measures (mitochondrial respiration, cytosolic and mCa2+, NADH, mFAD, mpH, IMM potential, and several ROS) and drugs available to search for the factors, the sequence of events, and the specific ROS that initiate PPC. PUBLIC HEALTH RELEVANCE: These studies will result in a better understanding of the regulation of mitochondrial bioenergetic function by Ca2+, K+, and ROS, and selection of the mitochondrion as a target for pharmacologic manipulation. This research should lead to the practical application of mitochondrial-targeted drugs to prophylactically treat patients with coronary artery disease using novel approaches.

描述（由申请人提供）：药理学预处理（PPC）是一种限制缺血再灌注（IR）损伤的方法，不需要事先短暂缺血或一旦发生缺血就需要药物的存在。 KATP 通道激动剂本身通过记忆途径诱导 PPC，从而通过更好的组织灌注、改善代谢和机械功能、减少心律失常和减少梗塞面积来评估心脏保护作用。我们对 PPC 特征和机制的理解有限，阻碍了对这种有效现象的最佳利用，以防止心脏 IR 损伤。尤其缺乏对线粒体在 PPC 中的作用的了解。大 (B) 电导 Ca2+ 敏感 K+ 通道 (BKCa) 也存在于心脏细胞线粒体内膜 (IMM) 中，似乎可以介导心脏保护作用。我们有证据表明 IMM 中的小电导 (S) KCa 通道也具有保护作用。我们提出，药物诱导的 K+ 进入线粒体 (m) 基质会改变生物能学，从而增加电子泄漏，从而诱导触发下游保护作用所需的活性氧 (ROS) 增加。初步结果表明，mKCa 通道开放的保护作用被超氧自由基歧化所阻断。 PPC 启动机制的统一假设可能是基质 K+ 流入诱导的 ROS 生成。我们将 a) 在豚鼠离体心脏线粒体中检查由基质 K+ 流入引发的导致 ROS 生成的生物能机制，b) 确定负责在豚鼠离体心脏中触发 PPC 的特定 ROS。此外，我们将 c) 通过蛋白质印迹、2D 凝胶电泳以及 MALDI-TOF 和 LIT SNCE 质谱法来识别这些通道，并表征人工脂质双层中的这些通道。我们将使用最好的技术、措施（线粒体呼吸、胞质和 mCa2+、NADH、mFAD、mpH、IMM 潜力和几种 ROS）和药物来寻找启动 PPC 的因素、事件顺序和特定 ROS 。公共健康相关性：这些研究将有助于更好地了解 Ca2+、K+ 和 ROS 对线粒体生物能功能的调节，并选择线粒体作为药理操作的靶点。这项研究应该会导致线粒体靶向药物的实际应用，以使用新方法预防性治疗冠状动脉疾病患者。