Metabolic Impact and Mechanism of Enhanced Mitochondrial Calcium Uptake in Mitochondrial Cardiomyopathies

线粒体钙摄取增强对线粒体心肌病的代谢影响和机制

• 批准号: 10391325
• 负责人: Dipayan Chaudhuri
• 金额: $ 38.13万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2023-07-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10391325
• 关键词: ATP Synthesis Pathway; Ablation; Affect; Animal Model; Animals; Biochemical; Biological Assay; Calcium; Calcium Signaling; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cell Death; Child; Complex; Coupling; Data; Disease; Failure; Feedback; Functional disorder; Genetic; Genetic Transcription; Goals; Heart; Heart failure; Homeostasis; Human; Impairment; Inborn Errors of Metabolism; Individual; Infant; Knock-out; Knockout Mice; Link; Measures; Mediating; Metabolic; Mitochondria; Mitochondrial DNA; Mitochondrial Matrix; Modification; Molecular; Mus; Mutagenesis; Mutation; Myocardial dysfunction; Nuclear; Organ; Outcome; Oxidative Phosphorylation; Pathologic Processes; Pathology; Pathway interactions; Phenotype; Post-Translational Protein Processing; Prevalence; Production; Prognosis; Proteins; Proteomics; Regulation; Regulatory Pathway; Research; Resistance; Respiration; Signal Transduction; Techniques; Testing; cell type; cyclophilin D; disease-causing mutation; electrical measurement; factor A; heart function; heart preservation; induced pluripotent stem cell; innovation; interest; knockout animal; loss of function; mitochondrial dysfunction; mitochondrial metabolism; mortality; mtTF1 transcription factor; mutant; novel; prevent; therapeutic target; transcription factor; uptake; virtual

PROJECT SUMMARY Diseases that arise from mutations in components of mitochondrial oxidative phosphorylation can be devastating, as mitochondria are crucial for energy synthesis. These diseases occur predominantly in infants and children, with a prevalence of 1 in 5000. Though virtually any organ can be affected, the heart is frequently involved, because cardiac function has such high energy requirements. These mitochondrial cardiomyopathies have a particularly grim prognosis, with mortality rates increased nearly three-fold compared to children without cardiac involvement. In linking cardiac function to mitochondrial metabolism, calcium signaling may be central to the pathological process. Calcium influx into the mitochondria can potently stimulate ATP synthesis, but excessive levels trigger mitochondrial failure and cell death. We hypothesize that, when oxidative phosphorylation becomes impaired, feedback regulation causes a compensatory increase in calcium influx, boosting ATP synthesis. However, after prolonged entry, mitochondrial calcium levels become excessive and trigger mitochondrial failure, exacerbating cardiac dysfunction. The rationale for this study is to determine whether such regulation exists in a well- characterized animal model of mitochondrial cardiomyopathies, which features genetic deletion of a mitochondrial transcription factor (Tfam) selectively in cardiomyocytes. The first aim is to determine whether the increased mitochondrial calcium levels found in preliminary studies are truly compensatory. For this aim, we will create animals with mitochondrial cardiomyopathies that have mitochondria that either cannot take up calcium, or are resistant to excessive calcium levels. The second objective is to determine the molecular mechanism causing enhanced mitochondrial calcium influx, and determine whether such enhancement can be replicated in cardiomyocytes derived from human induced pluripotent stem cells. In these analyses, we use an innovative set of techniques, including direct electrical measurement of mitochondrial calcium currents, that overcome technical challenges present in studying calcium transport. If successful, our research will define a significant new target for potential therapy in these devastating disorders.

项目概要 由线粒体氧化磷酸化成分突变引起的疾病可能是 毁灭性的，因为线粒体对于能量合成至关重要。这些疾病主要发生在 婴儿和儿童，患病率为五千分之一。虽然几乎任何器官都会受到影响，但心脏 经常涉及，因为心脏功能有如此高的能量需求。这些线粒体 心肌病的预后尤其严峻，死亡率增加近三倍 与没有心脏受累的儿童相比。将心脏功能与线粒体代谢联系起来， 钙信号传导可能是病理过程的核心。钙流入线粒体可以 有效刺激 ATP 合成，但过量会引发线粒体衰竭和细胞死亡。我们 假设，当氧化磷酸化受损时，反馈调节会导致 补偿性增加钙流入，促进 ATP 合成。然而，经过长时间的进入， 线粒体钙水平过高并引发线粒体衰竭，加剧心脏病 功能障碍。这项研究的基本原理是确定这种监管是否存在于良好的环境中。 线粒体心肌病的动物模型，其特征是基因缺失 线粒体转录因子（Tfam）选择性地存在于心肌细胞中。第一个目标是确定 初步研究中发现的线粒体钙水平增加是否真正是补偿性的。为了 为了实现这一目标，我们将创造患有线粒体心肌病的动物，这些动物的线粒体要么 不能吸收钙，或对过量的钙水平有抵抗力。第二个目标是确定 导致线粒体钙内流增强的分子机制，并确定这种现象是否存在 增强作用可以在源自人类诱导多能干细胞的心肌细胞中复制。在 在这些分析中，我们使用了一套创新技术，包括直接电气测量 线粒体钙电流，克服了研究钙转运中存在的技术挑战。如果 成功后，我们的研究将为这些毁灭性的疾病的潜在治疗确定一个重要的新目标 失调。