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

基本信息

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
项目类别：
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

项目摘要

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.

项目摘要由线粒体氧化磷酸化成分突变引起的疾病可以是毁灭性的，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5000分之一。尽管几乎任何器官都可能受到影响，但心脏是通常涉及，因为心脏功能具有如此高的能量需求。这些线粒体心肌病具有特别严峻的预后，死亡率增加了近三倍与没有心脏参与的儿童相比。在将心脏功能与线粒体代谢联系起来时，钙信号传导可能是病理过程的核心。钙流入线粒体可以有力刺激ATP合成，但水平过高会触发线粒体衰竭和细胞死亡。我们假设，当氧化磷酸化受到损害时，反馈调节会导致A 钙涌入的补偿性增加，增强ATP合成。但是，长时间进入后，线粒体钙水平变得过高并触发线粒体衰竭，加剧心脏功能障碍。这项研究的理由是确定这种调节是否存在线粒体心肌病的特征动物模型，该模型具有遗传缺失线粒体转录因子（TFAM）选择性地在心肌细胞中。第一个目的是确定初步研究中发现的线粒体钙水平是否确实是补偿性的。为了这个目标，我们将创建具有线粒体心肌病的动物，其线粒体是不能占据钙，也不能抵抗过度的钙水平。第二个目标是确定导致线粒体钙涌入的分子机制，并确定是否存在可以在人类诱导的多能干细胞衍生的心肌细胞中复制增强。在这些分析，我们使用了一套创新的技术，包括直接电气测量线粒体钙电流，它克服了研究钙转运中存在的技术挑战。如果成功，我们的研究将在这些破坏性的情况下定义一个重要的潜在治疗的新目标疾病。