BCL-XL AND THE HEART; THE METABOLIC BASIS TO CARDIOPROTECTION AND DISEASE

BCL-XL 与心脏；

• 批准号: 7953852
• 负责人: PETER JS SMITH
• 金额: $ 3.36万
• 依托单位: MARINE BIOLOGICAL LABORATORY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7953852
• 关键词: Address; Adenoviruses; Apoptotic; Attenuated; Bioenergetics; Biological Assay; Cardiac; Cardiac Myocytes; Cell Death; Cell Survival; Cells; Computer Retrieval of Information on Scientific Projects Database; Confocal Microscopy; Consumption; Disease; Dyes; Energy Metabolism; Esters; Free Radicals; Funding; Grant; Growth; Heart; Heart Diseases; Heart failure; Homeostasis; Inner mitochondrial membrane; Institution; Intervention; Ischemia; Kinetics; Luciferases; Measures; Membrane Potentials; Metabolic; Metabolism; Mitochondria; Mitochondrial Membrane Protein; Mitochondrial Proteins; Muscle Cells; Organ; Oxidative Phosphorylation; Oxygen; Production; Protein Overexpression; Proteins; Reaction; Regulation; Reperfusion Therapy; Research; Research Personnel; Resources; Signal Transduction; Societies; Source; Technology; United States National Institutes of Health; Up-Regulation; base; genetic regulatory protein; luciferin; member; mitochondrial membrane; mortality; prevent; receptor; therapeutic target; uptake

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Heart disease and consequent heart failure contibutes to high mortality in Western society. A greater understanding of the regulatory proteins associated with this disease is required. In heart, the anti-apoptotic factor, Bcl-xL attenuates cell death during ischemia-reperfusion. This is observed at the single cell and whole organ level. Though the pro-survival mechanism of Bcl-xl in unclear, Bcl-xl is thought to inhibit pro-apoptotic factors such as Bax and Bak while also regulating ATP-ADP exchange across the inner mitochondrial membranes. For example, anti-apoptotic Bcl-2 proteins (of which Bcl-xL is a member) inhibits the glycolytic consumption of ATP thereby maintaining the ATP pool during ischemia and preventing metabolic breakdown. Overexpression of these proteins in cardiac myocytes also maintains mitochondrial membrane potential and prevents the release of mitochondrial proteins during ischemic interventions. Prior studies on Bcl-xL in the heart have focused on mitochondrial transport kinetics, free radical production and cell death/growth assays. There is a lack of information concerning the metabolic changes associated with Bcl-xL, unexpected since Bcl-xL interacts directly with mitochondrial membrane proteins associated with the regulation of oxidative phosphorylation. In addition, there is limited information on Ca2+ homeostasis during cardioprotective and/or ischemic interventions. Bcl-xL-dependent modulation of IP3-receptors and mitochondrial Na+-Ca2+ exchange by Bcl-xL has been proposed and may contribute to the proposed cardioprotective qualities of Bcl-xL. The BRC aims to characterize the effect of Bcl-xl overepxression on both cellular energy metabolism and contractile function in cardiac myocytes. Metabolism will be assessed using self-referencing oxygen microsensors that will assess the oxygen uptake of control and Bcl-xL+ myocytes. In addition, myocytes will be co-infected with adenovirus containing constructs for cytosolic and mitochondrial luciferase in order to assess intracellular ATP concentration via the luciferin/luciferase reaction. Ca2+ homeostasis will be measured using AM ester Ca2+ dyes and confocal microscopy. It is the aim of the BRC to address whether there is a metabolic basis to the cardioprotective action of Bcl-2 proteins. In addition, it is our objective to assess Ca2+ transport and Ca2+-dependent signal transduction during Bcl-xL upregulation and to address whether this contributes to the observed changes in cardiac bioenergetics and cell survival. It is anticipated that integrated technologies available at the BRC will generate invaluable information regarding cardiac bioenergetics and identify potential therapeutic targets for the implementation of cardioprotection.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 心脏病和随之而来的心力衰竭导致西方社会的高死亡率。需要更好地了解与这种疾病相关的调节蛋白。在心脏中，抗凋亡因子 Bcl-xL 可减轻缺血再灌注期间的细胞死亡。这是在单细胞和整个器官水平上观察到的。 尽管 Bcl-xl 的促存活机制尚不清楚，但 Bcl-xl 被认为可以抑制 Bax 和 Bak 等促凋亡因子，同时还调节线粒体内膜上的 ATP-ADP 交换。例如，抗凋亡 Bcl-2 蛋白（Bcl-xL 是其中的成员）可抑制 ATP 的糖酵解消耗，从而在缺血期间维持 ATP 池并防止代谢分解。这些蛋白质在心肌细胞中的过度表达还可以维持线粒体膜电位并防止缺血干预期间线粒体蛋白质的释放。 先前对心脏中 Bcl-xL 的研究主要集中在线粒体转运动力学、自由基产生和细胞死亡/生长测定。缺乏关于与 Bcl-xL 相关的代谢变化的信息，这是出乎意料的，因为 Bcl-xL 直接与与氧化磷酸化调节相关的线粒体膜蛋白相互作用。此外，有关心脏保护和/或缺血干预期间 Ca2+ 稳态的信息有限。已提出 Bcl-xL 对 IP3 受体和线粒体 Na+-Ca2+ 交换的 Bcl-xL 依赖性调节，并可能有助于 Bcl-xL 的心脏保护作用。 BRC 旨在表征 Bcl-xl 过度表达对心肌细胞细胞能量代谢和收缩功能的影响。 将使用自参考氧微传感器评估代谢，该传感器将评估对照和 Bcl-xL+ 肌细胞的摄氧量。此外，肌细胞将与含有胞浆和线粒体荧光素酶构建体的腺病毒共同感染，以便通过荧光素/荧光素酶反应评估细胞内 ATP 浓度。 Ca2+ 稳态将使用 AM 酯 Ca2+ 染料和共聚焦显微镜进行测量。 BRC 的目的是解决 Bcl-2 蛋白的心脏保护作用是否存在代谢基础。此外，我们的目标是评估 Bcl-xL 上调期间的 Ca2+ 转运和 Ca2+ 依赖性信号转导，并确定这是否有助于观察到的心脏生物能学和细胞存活的变化。预计 BRC 提供的综合技术将产生有关心脏生物能学的宝贵信息，并确定实施心脏保护的潜在治疗靶点。