Relevance of mitochondrial calcium uniporter for mitochondrial myopathy

线粒体钙单向转运蛋白与线粒体肌病的相关性

• 批准号: 10595337
• 负责人: Erin Seifert
• 金额: $ 41.18万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10595337
• 关键词: Acute; Address; Aerobic Exercise; Affect; Area; Bioenergetics; Biology; Calcium; Cardiac; Cell Death; Cell Survival; Cell model; Cells; Complement; Complex; Crista ampullaris; Cytoplasm; DNA; Data; Disease Progression; Endoplasmic Reticulum; Environment; Evaluation; Human; Imaging Techniques; Incidence; Left; Link; Measurement; Metabolism; Methods; Mitochondria; Mitochondrial Diseases; Mitochondrial Myopathies; Mitochondrial Swelling; Modeling; Mus; Muscle Cells; Muscle Fibers; Muscle Mitochondria; Muscular Atrophy; Muscular Dystrophies; Mutation; Myoblasts; Myopathy; Nuclear; Organ; Oxidation-Reduction; Oxidative Phosphorylation; Pathology; Pattern; Pharmaceutical Preparations; Phase; Phosphate Carriers; Process; Production; Proteins; Publishing; Regulation; Reporting; Role; Side; Signal Pathway; Signal Transduction; Skeletal Muscle; Stress; Testing; Toxin; Translations; biological adaptation to stress; calcium uniporter; endoplasmic reticulum stress; exercise capacity; exercise intolerance; frataxin; imaging approach; imaging genetics; improved; in vivo; insight; literature survey; mitochondrial dysfunction; mitochondrial permeability transition pore; mouse model; muscle form; novel; pharmacologic; postmitotic; protein expression; proteostasis; response; sensor; skeletal; small molecule; uptake

Abstract: This project explores the intersection of two fundamental areas: cellular (mal)adaptation to primary mitochondrial dysfunction and the biology of the mitochondrial Ca2+ uniporter (MCUC). In humans, primary mitochondrial disease arises from mutations in nuclear- or mitochondrial-encoded DNA, or from pharmacological agents or toxins. Skeletal muscle is among the most severely affected organs. Mouse models of mitochondrial myopathy (MM) show that energy deficit, per se, is not the major factor for pathology, but, rather, that mitochondrial dysfunction initiate a progression of adaptive and maladaptive changes in, e.g., metabolism and proteostasis, and also activates endoplasmic reticulum (ER) stress and the Integrated Stress Response (ISR); the result is muscle atrophy, weakness, and diminished exercise capacity. Major cytoplasmic signaling pathways beyond the ISR have been investigated but found to not fully explain MM. Whether processes within mitochondria can impact MM progression has only been narrowly considered. Published data and our preliminary data document an increased abundance of the MCUC and increased mitochondrial Ca2+ uptake in MM and myopathies of other origins. The possibility that mitochondrial Ca2+ uptake contributes to pathology has only been considered in the context of MCUC's ability to cause a sustained opening of the mitochondrial permeability transition pore (mPTP), which can trigger cell death. Yet, our preliminary data suggest the hypothesis that the MCUC serves a beneficial role in MM, by expanding the oxidative phosphorylation capacity of dysfunctional muscle mitochondrial, and blunting the ISR. This hypothesis will be tested in two Specific Aims, by depletion MCUC in two models of MM (mice with depletion of PiC in skeletal muscle; mice with whole-body loss of Frataxin), for in vivo and ex vivo studies. We will also use advanced imaging techniques and genetic sensors to evaluate metabolism, bioenergetics and redox, and calcium, in a compartmentalized manner, including at the ER-mitochondria interface, in cells acutely depleted of MCUC. We will also use sophisticated methods to evaluate protein translation, since this is a key feature of the ISR that can influence muscle mass. Aim 1 will test the hypothesis that mitochondrial Ca2+ uptake improves energetics during the early phase of mitochondrial dysfunction. Aim 2 will determine how MCUC contributes to mitochondrial dysfunction-induced ER stress and the ISR and consequences on cell viability and muscle mass. Aim 3 will test the hypothesis that regulation of MCUC by MICU3 renders mitochondria vulnerable to sustained mPTP opening such that the MCUC becomes a liability for skeletal muscle at later phases of mitochondrial dysfunction. These studies are expected to reveal a novel role for MCUC in the (mal)adaptive response of skeletal muscle to mitochondrial dysfunction and in regulating muscle mass in myopathy, and, broadly, to provide new insight into the regulation of major stress signaling pathways that are activated in different myopathies, and many other stress conditions. .

摘要：该项目探讨了两个基本领域的交集：蜂窝（MAL）适应 线粒体功能障碍和线粒体Ca2+ Uniporter（MCUC）的生物学。在人类中 原发性线粒体疾病是由核或线粒体编码的DNA的突变引起的，或者是由 药理学剂或毒素。骨骼肌是受影响最严重的器官之一。老鼠 线粒体肌病（MM）的模型表明，能量不足本身并不是主要因素 病理学，而是，线粒体功能障碍引发了适应性和适应不良的进展 例如，新陈代谢和蛋白质症的变化，还激活内质网（ER）应激和 综合应力反应（ISR）；结果是肌肉萎缩，无力和运动能力降低。 已经研究了ISR以外的主要细胞质信号通路，但发现并未完全解释MM。 线粒体内的过程是否会影响MM进展。 发布的数据和我们的初步数据文档增加了MCUC和 MM和其他起源的肌病中的线粒体Ca2+摄取增加。可能性 线粒体Ca2+摄取仅在MCUC的能力中考虑到有助于病理学 引起线粒体通透性过渡孔（MPTP）的持续开放，这可以触发细胞 死亡。然而，我们的初步数据表明，MCUC在MM，通过 扩展功能失调的肌肉线粒体的氧化磷酸化能力，并使 ISR。该假设将通过两种MM模型（小鼠 随着骨骼肌中的PIC耗尽； frataxin全身损失的小鼠），体内和外体内的小鼠 研究。我们还将使用先进的成像技术和遗传传感器来评估新陈代谢， 生物能和氧化还原和钙以分隔的方式，包括在ER-线粒体上 界面，在急性耗尽MCUC的细胞中。我们还将使用复杂的方法评估蛋白质 翻译，因为这是ISR的关键特征，可以影响肌肉质量。 AIM 1将检验假设 线粒体CA2+摄取在线粒体功能障碍的早期阶段改善了能量。 AIM 2将决定MCUC如何促进线粒体功能障碍诱导的ER应力和ISR 以及对细胞活力和肌肉质量的后果。 AIM 3将检验MCUC调节的假设 通过MICU3使线粒体容易受到持续的MPTP开放的影响，因此MCUC成为一个 线粒体功能障碍的后期骨骼肌的责任。这些研究有望揭示 MCUC在骨骼肌肉对线粒体功能障碍和（MAL）自适应反应中的新作用 在调节肌病中的肌肉质量方面，并广泛地提供了对主要调节的新见解 应力信号通路在不同的肌病和许多其他压力状况下被激活。 。