Investigate the effect of mitochondrial energy state on Ca2+ sparks and handling

研究线粒体能量状态对 Ca2 火花和处理的影响

• 批准号: 7639770
• 负责人: Lufang Zhou
• 金额: $ 7.59万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7639770
• 关键词: Acute; American; Cardiac; Cardiac Myocytes; Cavia; Cells; Communication; Computer Simulation; Coupling; Development; Electrophysiology (science); Energy Metabolism; Event; Feedback; Frequencies; Functional disorder; Glutathione; Hand; Heart Diseases; Heart failure; Image; Individual; Injury; Ion Channel; Ischemia; Lasers; Link; Membrane Potentials; Metabolic; Metabolism; Microscope; Mitochondria; Modeling; NADH; Oxidation-Reduction; Oxidative Phosphorylation; Oxidative Stress; Pattern; Principal Investigator; Probability; Process; Production; Property; Pyrimidine Nucleotides; Reactive Oxygen Species; Regulation; Reperfusion Therapy; Rest; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Sarcomeres; Signal Transduction; Simulate; Site; Source; System; Work; experimental analysis; follow-up; models and simulation; novel; spatiotemporal; two-photon; uptake

DESCRIPTION(provided by applicant): Heart disease is the single largest killer of the American. A growing body of evidence has shown that there is a close relationship between Ca2+ handling abnormalities and development of heart disease. Therefore it is fundamentally important to understand the regulation of Ca2+ signaling under pathological conditions. Local control of Ca2+-induced Ca2+ release (CICR) depends on the spatial organization of L-type Ca2+ channels and ryanodine receptors (RyR) in the dyad. Analogously, Ca2+ uptake by mitochondria is facilitated by their close proximity to the Ca2+ release sites, a process required for stimulating oxidative phosphorylation during changes in work. Mitochondrial feedback on CICR, however, is less well understood. Since mitochondria are a primary source of reactive oxygen species (ROS), they could potentially influence the cytosolic redox state, in turn altering RyR open probability. In this proposed study, a two photon laser microscope system will be used to directly examine how acute changes in energy state dynamically influence Ca2+ spark properties under various experimental conditions. Cytosolic Ca2+ (or ROS), A^m, and NADH will be recorded simultaneously in isolated guinea pig cardiomyocytes and analyzed offline using imaged. The spatiotemporal coupling between mitochondria! depolarization and Ca2+ sparks will be analyzed using a quantitative approach. Furthermore, a computational model of mitochondria and Ca2+ release unit will be developed to quantitatively investigate the interaction between mitochondrial energetics and local Ca2+ handling. Finally, an integrated model of the cardiomyocyte incorporating substrate metabolism, cellular electrophysiology, pH regulation and E-C coupling will be developed to investigate the mechanisms underlying alterations in energy production, ion channels, Ca2+ handling and pH, as well as the resulting reduction of cardiac contractile function during ischemia-reperfusion. By combining the experimental and computational results, these studies will allow for a complete understanding the origin of post-ischemic injury and development of heart failure, and significantly spur the development of novel heart disease therapies.

描述（由申请人提供）：心脏病是美国人最大的杀手。越来越多的证据表明，CA2+处理异常与心脏病的发展之间存在密切的关系。因此，了解病理条件下的CA2+信号传导的调节至关重要。 Ca2+诱导的Ca2+释放（CICR）的局部控制取决于Dyad中L型Ca2+通道和ryanodine受体（RYR）的空间组织。类似地，通过与Ca2+释放位点的近距离促进了线粒体的Ca2+摄取，这是在工作变化过程中刺激氧化磷酸化所需的过程。然而，线粒体反馈对CICR的反馈知之甚少。由于线粒体是活性氧（ROS）的主要来源，因此它们可能会影响胞质氧化还原态，从而改变RYR开放概率。在这项拟议的研究中，将使用两个光子激光显微镜系统直接研究能量状态的急性变化如何在各种实验条件下动态影响Ca2+火花特性。胞质Ca2+（或ROS），A^M和NADH将同时记录在孤立的豚鼠心肌细胞中，并使用成像进行离线分析。线粒体之间的时空耦合！去极化和Ca2+火花将使用定量方法分析。此外，将开发线粒体和Ca2+释放单元的计算模型，以定量研究线粒体能量之间的相互作用 和本地CA2+处理。最后，掺入底物的心肌细胞的集成模型 将开发代谢，细胞电生理学，pH调节和E-C耦合，以研究能源产生，离子通道，Ca2+处理和pH的改变的机制，以及导致的缺血性重新灌注期间的心脏收缩功能的降低。通过结合实验和计算结果，这些研究将允许完全了解缺血后损伤的起源和心力衰竭的发展，并显着刺激了新型心脏病疗法的发展。