Aberrant ER-mitochondria communication in human mitochondrial disease

人类线粒体疾病中异常的内质网-线粒体通讯

• 批准号: 10247029
• 负责人: ERIC A. SCHON
• 金额: $ 52.23万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10247029
• 关键词: Affect; Bacteria; Biochemical; Biochemical Genetics; Biochemistry; Bioenergetics; Brain; Calcium; Cells; Cholesterol; Clinical; Communication; Complex; DNA; Defect; Diagnostic; Disease; Endoplasmic Reticulum; Energy Metabolism; Functional disorder; Genes; Genetic; Genome; Goals; Homeostasis; Human; Induced pluripotent stem cell derived neurons; Interphase Cell; Knowledge; MELAS Syndrome; Measures; Mediating; Membrane; Membrane Proteins; Microscopy; Mitochondria; Mitochondrial DNA; Mitochondrial Diseases; Mitochondrial Proteins; Mutate; Mutation; Myocardium; Neurodegenerative Disorders; Nuclear; Organelles; Output; Oxidative Phosphorylation; Palliative Care; Pathogenesis; Pathogenicity; Pathology; Patients; Pharmacology; Phenotype; Phospholipids; Play; Positioning Attribute; Production; Proteins; Respiratory Chain; Role; Running; Stress; Structure; Sulforaphane; System; Testing; Therapeutic; Thinking; Time; Toxin; base; calcium metabolism; clinical heterogeneity; improved; inhibitor/antagonist; insight; lipid metabolism; lipidomics; metabolomics; overexpression; protein distribution; response

Mitochondrial disease, defined as a group of disorders due to defects in the respiratory chain/oxidative-phosphorylation system (OxPhos), comprises an important group of pathologies that are challenging to study and treat, as they are among the most heterogeneous human conditions at every level: clinical, biochemical, and genetic. Mitochondria are under dual genetic control, dependent on both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). Pathogenic mutations in genes encoded by both genomes give rise to mitochondrial disease, many of which are neurodegenerative disorders that typically are both devastating and ultimately fatal. Mutations in mtDNA genes affect structural subunits of the OxPhos system, whereas mutations in nDNA genes are more numerous and diverse, as they encode not only a large number of OxPhos subunits but also factors needed for the proper synthesis, assembly, and functioning of the OxPhos machinery. We recently discovered that in cells from patients with mitochondrial disease there is a significant disruption in the intimate communication, both physical and biochemical, between mitochondria and endoplasmic reticulum (ER) at "mitochondria-associated ER membranes (MAM)". MAM is a central locus for maintaining cellular cholesterol, phospholipid, and calcium homeostasis, as well as regulating mitochondrial bioenergetics and dynamics (organellar fusion, fission, and positioning). Based on this finding, we hypothesize that reductions in oxidative energy metabolism can disrupt ER-mitochondrial communication, with serious consequences for cell survivability that go well beyond that of reduced ATP output. The objectives of this application - and our Specific Aims - are thus threefold: (1) to deduce the genetic and biochemical circumstances under which OxPhos deficits affect MAM (the "phenotypic landscape"), by analyzing cells from patients with known mutations in nDNA and mtDNA causing OxPhos deficiency, and by perturbing bioenergetics with specific OxPhos toxins; (2) to gain insight into the mechanism by which this occurs, using both biased (i.e. targeted) and unbiased approaches to identify OxPhos-related factors that affect ER-mitochondrial connectivity; and (3) to determine if we can use either genetic or pharmacological approaches to improve ER-mitochondrial communication in cells with genetically-compromised bioenergetics, thereby revealing "latent" OxPhos potential (i.e. improved OxPhos output and efficiency) and increasing bioenergetic output, even in cells with a high mutation load. Our discovery of an "OxPhos-MAM connection" has revealed a hitherto unknown pathogenetic role of altered inter-organellar communication in mitochondrial disease. In turn, this has opened up a new way of thinking about the pathogenesis and treatment of mitochondrial disease. A therapeutic strategy based on "fixing" ER-mitochondrial connectivity to re-normalize MAM function will likely be generalizable to a large number of mitochondrial disorders.

线粒体疾病被定义为由呼吸链/氧化磷酸化系统 (OxPhos) 缺陷引起的一组疾病，包括一组具有挑战性的重要病理学研究 并进行治疗，因为它们是各个层面上最异质的人类病症之一：临床、生化、 和遗传。线粒体受到双重遗传控制，依赖于核 DNA (nDNA) 和 线粒体DNA（mtDNA）。两个基因组编码的基因的致病突变会导致 线粒体疾病，其中许多是神经退行性疾病，通常具有破坏性和 最终是致命的。 mtDNA 基因突变影响 OxPhos 系统的结构亚基，而突变 nDNA 基因数量更多且多样化，因为它们不仅编码大量的 OxPhos 亚基 还包括 OxPhos 机械的正确合成、组装和功能所需的因素。 我们最近发现，在线粒体疾病患者的细胞中，存在显着的 线粒体和线粒体之间的物理和生化亲密交流受到破坏 内质网 (ER) 位于“线粒体相关 ER 膜 (MAM)”。 MAM 是一个中心位点 维持细胞胆固醇、磷脂和钙稳态，以及调节线粒体 生物能量学和动力学（细胞器融合、裂变和定位）。基于这一发现，我们假设 氧化能量代谢的减少会破坏内质网与线粒体的通讯，从而造成严重的后果 对细胞存活率的影响远远超出了 ATP 输出减少的影响。 因此，该应用程序的目标 - 以及我们的具体目标 - 有三个：（1）推断遗传和 OxPhos 缺陷影响 MAM（“表型景观”）的生化环境，通过 分析已知导致 OxPhos 缺乏的 nDNA 和 mtDNA 突变的患者的细胞，并通过 使用特定的 OxPhos 毒素扰乱生物能； (2)深入了解其发生的机制 发生时，使用有偏见（即有针对性）和无偏见的方法来识别影响 OxPhos 的相关因素 ER-线粒体连接； (3) 确定我们是否可以使用遗传或药理学方法 改善具有遗传受损生物能的细胞内质网-线粒体通讯的方法， 从而揭示“潜在”OxPhos 潜力（即提高 OxPhos 输出和效率）并增加 生物能量输出，即使在具有高突变负荷的细胞中也是如此。 我们对“OxPhos-MAM 连接”的发现揭示了迄今为止未知的致病作用 线粒体疾病中细胞器间通讯的改变。反过来，这又开辟了一条新的途径 思考线粒体疾病的发病机制和治疗。治疗策略基于 “修复”ER-线粒体连接以重新正常化 MAM 功能可能会推广到大范围 线粒体疾病的数量。