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升高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。