ADP: A Master Regulator for Bioenergetics and Ca2+/ROS Signaling in Heart

ADP：心脏生物能学和 Ca2/ROS 信号传导的主调节器

• 批准号: 8198299
• 负责人: Shey-Shing Sheu
• 金额: $ 23.25万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8198299
• 关键词: 3-Methylglutaconic aciduria type 2; Accounting; Adenine Nucleotide Translocase; Adenosine Diphosphate; Adenosine Triphosphate; Affect; Aging; Apoptosis; Binding; Bioenergetics; Buffers; Cardiac; Cardiac Myocytes; Cardiolipins; Cell Death; Cell Death Signaling Process; Cells; Cessation of life; Chronic; Citric Acid Cycle; Complex; Coupling; Crista ampullaris; Cyclosporine; Defect; Diabetes Mellitus; Disease; Effectiveness; Electron Transport; Enzymes; Exhibits; Failure; Family member; Feedback; Generations; Heart; Heart Diseases; Heart failure; Hyperglycemia; Injury; Lead; Life; Link; Maintenance; Mediating; Medical; Membrane; Metabolic; Metabolism; Mitochondria; Modeling; Molecular; Molecular Conformation; Myocardial Infarction; Neurodegenerative Disorders; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Peptidylprolyl Isomerase; Phospholipids; Predisposition; Process; Proteins; Reperfusion Injury; Research; Respiratory Chain; Role; SLC25A5 gene; Scheme; Signal Transduction; Site; Stress; Stroke; Superoxides; Testing; Therapeutic; Voltage-Dependent Anion Channel; cell type; cyclophilin D; diabetic cardiomyopathy; dithiol; electron donor; genetic regulatory protein; heart cell; hexokinase; high risk; human disease; inhibitor/antagonist; inorganic phosphate; insight; mitochondrial creatine kinase; mitochondrial dysfunction; mitochondrial permeability transition pore; oxidation; protein complex; pyridine nucleotide; ubisemiquinone; uptake

DESCRIPTION (provided by applicant): Heart failure is a serious medical problem: over 5 million people in the US affected. The cause for chronic heart failure is multifaceted and includes bioenergetic deficiency, Ca2+ overload, and oxidative stress. ADP is the key substrate for ATP formation. Moreover, ADP is a potent inhibitor for the opening of mitochondrial permeability transition pore (mPTP). Although the molecular identity of mPTP is still unsolved, 2 different concepts stand out. One indicates that adenine nucleotide translocase (ANT) is not required for mPTP, whereas the other depicts mPTP as a multi-protein complex, the ANT and the mitochondrial peptidyl-prolyl cis-trans isomerase known as cyclophilin-D (Cyp-D), are the key components. Interestingly, binding of ADP to ANT facilitates cardiolipin to stabilize respiratory chain supercomplexes so that the efficiency of ATP generation is enhanced. Oxidation of cardiolipin destabilizes these supercomplexes and has been linked to mitochondrial dysfunction associated with aging, diabetic cardiomyopathy, ischemia-reperfusion injury, and heart failure. Furthermore, ADP inhibits efflux of inorganic phosphate Pi, the key mitochondrial Ca2+ buffer that forms Ca2+-Pi complex. Finally, activation of the mitochondrial fission protein, DLP1 causes mitochondrial fission, ROS generation, and mPTP opening. Taken together, these results lead us to hypothesize that "binding of ADP to ANT serves two fundamental roles in mitochondrial function: enhancing ATP generation efficiency by stabilizing cardiolipin-ETC complexes and inhibiting mPTP by decreasing ROS generation and DLP1 activation. Physiologically, ADP- mediated mPTP inhibition minimizes excessive mitochondrial ROS generation and Ca2+ release from mitochondria in order to optimize the effectiveness of excitation-contraction-metabolism (ECM) coupling. Pathologically, defects of this ADP regulatory mechanism lead to energetic failure, oxidative stress, and Ca2+ dysregulation that enhance cardiac vulnerability to injury". We propose 2 Specific Aims: Specific Aim 1: To determine the mechanisms for ADP inhibition of mPTP. Hypothesis: ADP stabilizes cardiolipin integrity and inhibits DLP1 activity in the mitochondria and thus protects against Cyp-D-independent mPTP opening. Moreover, ADP decreases ROS generation via mPTP inhibition, and thus minimizes feedback activation of mPTP by ROS. Specific Aim 2: To assess the role of ADP in cardiac protection. Hypothesis: The mPTP in hearts of diseased models exhibits increased sensitivity to Ca2+-induced opening due to its predisposition to the first hit stresses including oxidative stress, high DLP1 activity, and/or diminished Ca2+ buffering capacity. Maintenance of optimal matrix ADP levels alleviates this increased mPTP vulnerability. Disturbances in the interaction between metabolic signaling and Ca2+/redox/cell death signaling are fundamental in disease pathogenesis including cardiac diseases. The exploratory and high-risk ideas in this application, if validated, will break new ground in a wide spectrum of disease mechanisms and treatments. PUBLIC HEALTH RELEVANCE: Failure to provide sufficient cellular energy in form of ATP can cause numerous human diseases including heart attacks and strokes, neurodegenerative diseases, diabetes, and aging. The proposed research will explore the dual role of ADP in serving as a substrate for making ATP and an inhibitor for oxidative stress. It is our objective, not only to elucidate the fundamental mechanisms how ADP regulates the life and death of heart cells, but also to develop possible therapeutic means for treating these debilitating disorders.

描述（由申请人提供）：心力衰竭是一个严重的医疗问题：美国有超过 500 万人受到影响。慢性心力衰竭的原因是多方面的，包括生物能缺乏、Ca2+超载和氧化应激。 ADP 是 ATP 形成的关键底物。此外，ADP 是线粒体通透性转换孔 (mPTP) 打开的有效抑制剂。尽管 mPTP 的分子身份仍未解决，但有两个不同的概念脱颖而出。一种表明 mPTP 不需要腺嘌呤核苷酸转位酶 (ANT)，而另一种则将 mPTP 描述为一种多蛋白复合物、ANT 和线粒体肽基脯氨酰顺反异构酶，称为亲环蛋白-D (Cyp-D)，是关键部件。有趣的是，ADP与ANT的结合有助于心磷脂稳定呼吸链超复合物，从而提高ATP生成的效率。心磷脂的氧化会破坏这些超级复合物的稳定性，并与衰老、糖尿病心肌病、缺血再灌注损伤和心力衰竭相关的线粒体功能障碍有关。此外，ADP 抑制无机磷酸盐 Pi 的流出，Pi 是形成 Ca2+-Pi 复合物的关键线粒体 Ca2+ 缓冲剂。最后，线粒体裂变蛋白 DLP1 的激活导致线粒体裂变、ROS 生成和 mPTP 打开。综上所述，这些结果使我们推测“ADP 与 ANT 的结合在线粒体功能中发挥着两个基本作用：通过稳定心磷脂-ETC 复合物来提高 ATP 生成效率，并通过减少 ROS 生成和 DLP1 激活来抑制 mPTP。生理学上，ADP 介导的mPTP 抑制可最大限度地减少线粒体 ROS 的过量生成和线粒体 Ca2+ 的释放，从而优化兴奋-收缩-代谢 (ECM) 耦合的有效性。从病理上讲，这种 ADP 调节机制的缺陷会导致能量衰竭、氧化应激和 Ca2+ 失调，从而增加心脏对损伤的脆弱性。”我们提出 2 个具体目标： 具体目标 1：确定 ADP 抑制 mPTP 的机制。假设：ADP 稳定心磷脂完整性并抑制线粒体中的 DLP1 活性，从而防止不依赖 Cyp-D 的 mPTP 打开。此外，ADP 通过抑制 mPTP 减少 ROS 的产生，从而最大限度地减少 ROS 对 mPTP 的反馈激活。具体目标 2：评估 ADP 在心脏保护中的作用。假设：患病模型心脏中的 mPTP 对 Ca2+ 诱导的开放表现出更高的敏感性，因为它易于受到第一次打击应激，包括氧化应激、高 DLP1 活性和/或 Ca2+ 缓冲能力减弱。维持最佳矩阵 ADP 水平可以缓解这种增加的 mPTP 脆弱性。代谢信号与 Ca2+/氧化还原/细胞死亡信号之间相互作用的干扰是包括心脏病在内的疾病发病机制的基础。该应用中的探索性和高风险想法如果得到验证，将在广泛的疾病机制和治疗方面开辟新天地。 公共健康相关性：未能以 ATP 形式提供足够的细胞能量可能会导致多种人类疾病，包括心脏病和中风、神经退行性疾病、糖尿病和衰老。拟议的研究将探索 ADP 作为制造 ATP 的底物和氧化应激抑制剂的双重作用。我们的目标不仅是阐明 ADP 如何调节心脏细胞的生命和死亡的基本机制，而且还开发可能的治疗方法来治疗这些使人衰弱的疾病。