Cations and ROS in Modulating Mitochondrial Function in Normal and Ischemic Heart

阳离子和 ROS 调节正常和缺血心脏线粒体功能

• 批准号: 8241133
• 负责人: AMADOU K. CAMARA
• 金额: $ 52.15万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8241133
• 关键词: Abbreviations; Adenine Nucleotide Translocase; Apoptosis; Binding; Bioenergetics; Biological Assay; Biophysics; Buffers; Cardiac; Cardiac Myocytes; Cations; Cell Death; Cell Membrane Permeability; Cell physiology; Cessation of life; Chronic; Chronic Disease; Citric Acid Cycle; Complement; Complex; Computer Simulation; Data; Defect; Development; Disease; Electrodes; Electrons; Electrophysiology (science); Energy Metabolism; Engineering; Eukaryotic Cell; Experimental Designs; Fluorescence; Free Energy; Functional disorder; Generations; Glutathione; Glutathione Disulfide; Glutathione Reductase; Goals; Health; Heart; Homeostasis; Hydrogen; Hydrogen Peroxide; Individual; Ionophores; Ions; Ischemia; Kinetics; Lead; Manganese Superoxide Dismutase; Measurement; Measures; Mediating; Membrane Potentials; Metabolic; Mitochondria; Modeling; Myocardial Ischemia; NAD(P)+ transhydrogenase; NADH; Organ; Outer Mitochondrial Membrane; Oxidation-Reduction; Oxidative Phosphorylation; Pathogenesis; Pensions; Physiological; Physiology; Potassium Channel; Process; Production; Public Health; Pyruvate; Reactive Oxygen Species; Recovery; Regulation; Reperfusion Injury; Reperfusion Therapy; Research; Respiration; Respiratory System; Role; Ruthenium Red; Signal Transduction; Succinates; Superoxides; System; Techniques; Testing; Thioredoxin; Time; Whole Organism; base; cell injury; channel blockers; chemical kinetics; computerized data processing; design; glutaredoxin; glutathione peroxidase; human SOD2 protein; improved; inhibitor/antagonist; inorganic phosphate; mitochondrial dysfunction; mitochondrial membrane; mitochondrial permeability transition pore; new therapeutic target; novel; novel strategies; peroxiredoxin; prevent; public health relevance; research study; response; thioredoxin reductase; tool

DESCRIPTION (provided by applicant): Mitochondria are the powerhouse of eukaryotic cells such as cardiomyocytes. Besides their role in free energy transduction, they are responsible for maintaining intracellular ionic homeostasis (e.g., Ca2+, Na+, Mg2+, H+, K+) and handling toxic byproducts of energy metabolism (e.g., ROS). Consequently, functional defects in these processes can lead to mitochondrial dysfunction, cell death, and pathogene- sis of several diseases. A quantitative understanding of regulation of mitochondrial function through the kinetics of mitochondrial cation transport and buffering and ROS generation and scavenging will be cru- cial in developing a systems-based, engineering understanding of mitochondrial, cellular, whole-organ, and whole-organism function and associated disease processes. The overall goal of this collaborative proposal is therefore to quantify the biophysics and chemical kinetics associated with mitochondrial handling of pH, cations, and ROS in cardiomyocytes and to understand how they individually and col- lectively influence mitochondrial function. We hypothesize that cations selectively inhibit or activate specific cation channels and exchangers to regulate trans-matrix fluxes and intra-matrix concentrations of these cations. Furthermore, the intra-matrix free concentrations of cations (e.g., Ca2+) are governed by a dynamic buffering mechanism due to dynamic binding of the cations with phosphates (ATP, ADP, PI) and substrates (TCA cycle intermediates) during transient respiration, which in turn regulate mito- chondrial function, including the rate of ROS generation. Pathophysiological and chronic alterations in these mechanisms can lead to mitochondrial dysfunction and cellular injury. These hypotheses will be tested through an iterative process between experimental measurements and computational modeling of mitochondrial bioenergetics and electrophysiology (changes in trans-matrix cation concentrations and fluxes, NADH and FAD redox states, membrane potential, respiration, and ROS production with normal and abnormal perturbations in extra-matrix cation concentrations) in both isolated cardiac mito- chondria and isolated intact hearts, with the refinement of both the experimental design and computa- tional model as the research unfolds. The model will provide the basis for improving the experimental design and specific hypotheses; in turn, the experimental data will provide the basis to refine and ex- tend the model. By the use of this integrative approach we will also be able to understand regulation of ROS production during ischemia and reperfusion (I/R). Recovery of cardiac function after I/R is critically dependent on rapid recovery of mitochondrial function to restore ATP production, which prevents de- rangement of cytosolic and mitochondrial cation homeostasis and avoid cellular injury or death. The proposed combined approach represents a novel strategy in understanding the integrated function of cardiomyocytes under physiological and pathophysiological conditions. PUBLIC HEALTH RELEVANCE: Relevance of the research to public health: The process of combined computational modeling with experimental measurements of mitochondrial bioenergetics and electrophysiology provides an iterative process to formulate and quantitatively test complex hypotheses regarding regulation of mitochondrial function in health and disease. The proposed research examines the inter-relationships between the kinetics of mitochondrial bioenergetics, electrophysiology, cation and ROS handling, and the dynamic regulation of mitochondrial and cellular function in the heart in health and disease. These studies will provide a novel and rational mechanistic approach for the identification of new therapeutic targets and the development of new therapies (e.g., cation channel blockers or openers) to alleviate mitochondrial dysfunction and preserve cellular viability.

描述（由申请人提供）：线粒体是真核细胞（例如心肌细胞）的动力源。除了在自由能量转导中的作用外，它们还负责维持细胞内离子稳态（例如 Ca2+、Na+、Mg2+、H+、K+）和处理能量代谢的有毒副产物（例如 ROS）。因此，这些过程中的功能缺陷可能导致线粒体功能障碍、细胞死亡和多种疾病的发病机制。通过线粒体阳离子运输和缓冲以及ROS生成和清除的动力学来定量了解线粒体功能的调节对于开发对线粒体、细胞、整个器官和整个有机体功能的基于系统的工程理解至关重要以及相关的疾病过程。因此，该合作提案的总体目标是量化与心肌细胞中 pH、阳离子和 ROS 线粒体处理相关的生物物理学和化学动力学，并了解它们如何单独和共同影响线粒体功能。我们假设阳离子选择性地抑制或激活特定的阳离子通道和交换器，以调节这些阳离子的跨基质通量和基质内浓度。此外，由于瞬时呼吸期间阳离子与磷酸盐（ATP、ADP、PI）和底物（TCA 循环中间体）的动态结合，基质内游离的阳离子浓度（例如 Ca2+）受到动态缓冲机制的控制，这反过来调节线粒体功能，包括ROS产生的速率。这些机制的病理生理学和慢性改变可能导致线粒体功能障碍和细胞损伤。这些假设将通过线粒体生物能量学和电生理学的实验测量和计算模型之间的迭代过程进行测试（跨基质阳离子浓度和通量、NADH 和 FAD 氧化还原状态、膜电位、呼吸和 ROS 产生与正常和异常扰动的变化）基质外阳离子浓度）在分离的心脏线粒体和分离的完整心脏中，随着实验设计和计算模型的改进研究展开。该模型将为改进实验设计和具体假设提供依据；反过来，实验数据将为完善和扩展模型提供基础。通过使用这种综合方法，我们还将能够了解缺血和再灌注 (I/R) 期间 ROS 产生的调节。 I/R后心脏功能的恢复关键取决于线粒体功能的快速恢复，以恢复ATP的产生，从而防止细胞质和线粒体阳离子稳态的紊乱，并避免细胞损伤或死亡。所提出的组合方法代表了理解心肌细胞在生理和病理生理条件下的综合功能的新策略。 公共健康相关性：研究与公共健康的相关性：将计算模型与线粒体生物能量学和电生理学实验测量相结合的过程提供了一个迭代过程，用于制定和定量测试有关健康和疾病中线粒体功能调节的复杂假设。拟议的研究探讨了线粒体生物能量学、电生理学、阳离子和活性氧处理的动力学，以及健康和疾病状态下心脏线粒体和细胞功能的动态调节之间的相互关系。这些研究将为识别新治疗靶点和开发新疗法（例如阳离子通道阻滞剂或开放剂）提供新颖且合理的机制方法，以减轻线粒体功能障碍并保持细胞活力。