Investigating the role of cardiolipin metabolism in mitochondrial DNA replication and mitochondrial division

研究心磷脂代谢在线粒体 DNA 复制和线粒体分裂中的作用

• 批准号: MR/S002065/1
• 负责人: Robert Pitceathly
• 金额: $ 138.07万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FS002065%2F1
• 关键词: Investigating; role; cardiolipin; metabolism; mitochondrial

Mitochondria provide the major source of energy in human cells and control numerous metabolic pathways. Thirteen subunits of the energy producing machinery are encoded by DNA present in the mitochondria (mitochondrial DNA, mtDNA); while the vast majority of the mitochondrial proteome (>1,500 predicted proteins) are encoded by the nuclear genome and are actively imported into the organelles from the cytosol. Mitochondrial diseases, inherited conditions caused by mutations in nuclear- and mtDNA-encoded mitochondrial genes which impair mitochondrial function, are among the most common genetic neurological disorders, affecting 1 in 4,300 individuals. They often cause devastating illness associated with severe disability and shortened lifespan in children and adults. Unfortunately, there are currently no effective treatments that halt or reverse progression of the disease.One emerging, but poorly-characterised, category of mitochondrial diseases relates to impaired phospholipid metabolism. Cardiolipin (CL) is a phospholipid (PL) found only in mitochondrial membranes with numerous essential mitochondrial functions. CL biosynthesis is a complex process, involving the endoplasmic reticulum (ER), a network of membranous tubules within the cytoplasm of the cell, continuous with the nuclear membrane, and the mitochondria. However, it is ultimately synthesised from phosphatidic acid (PA) within the inner mitochondrial membrane (IMM). Crucial for the transfer of PA from the ER to the IMM is the TRIAP1-PRELID1 complex. Further evidence for the intrinsic connection between the ER and mitochondria has recently emerged with evidence that mtDNA replication occurs at ER-mitochondria contact sites, thus coupling mtDNA synthesis and mitochondrial division. However, the mechanism that links mtDNA synthesis to mitochondrial division, and the impact of perturbed ER-mitochondria contact sites on mtDNA replication, remains poorly-understood.I have identified a patient, in the NHS England Highly Specialised Services for Mitochondrial Disorders that I help run at the National Hospital for Neurology and Neurosurgery, with the first pathogenic mutations (resulting in frameshift of the protein) in the human TRIAP1 gene, the protein product of which is crucial to CL biosynthesis. I have undertaken detailed investigations that reveal impaired CL metabolism and aberrant mtDNA replication in both patient-derived fibroblasts and muscle tissue. This new discovery supports the importance of phospholipid homeostasis in mtDNA maintenance and presents a significant opportunity to advance understanding of fundamental aspects of mitochondrial biology.The overarching research aim of my fellowship is to gain a deeper understanding of how CL metabolism influences mtDNA synthesis and mitochondrial division. The key objectives are to: 1) characterise how perturbed CL metabolism influences mtDNA replication and mitochondrial division; 2) define the TRIAP1 interactome and identifying novel proteins required for CL biosynthesis and PL trafficking; and 3) investigate muscle-specific CL biosynthesis and PL trafficking pathways. These objectives will be achieved by studying CL metabolism and PL trafficking pathways in the following cell models: mutant and knockout (KO) TRIAP1 fibroblasts; mutant TRIAP1 human induced pluripotent stem cell (hiPSC)-derived myoblasts, using a combined cell biology and proteomics approach. The research will be undertaken at the UCL Institute of Neurology, a world-leading neuroscience centre, in collaboration with: the MRC-Mitochondrial Biology Unit, University of Cambridge (Professor Massimo Zeviani), an internationally-recognised centre of excellence for the study of mitochondrial biology and medicine; and the Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne (Professor Thomas Langer), a leading European institution for mitochondrial biology and aging.

线粒体提供人体细胞的主要能量来源并控制许多代谢途径。能量产生机制的 13 个亚基由线粒体中的 DNA（线粒体 DNA，mtDNA）编码；而绝大多数线粒体蛋白质组（> 1,500 种预测蛋白质）由核基因组编码，并主动从细胞质导入细胞器。线粒体疾病是由核和 mtDNA 编码的线粒体基因突变引起的遗传性疾病，会损害线粒体功能，是最常见的遗传性神经系统疾病之一，每 4,300 人中就有 1 人受到影响。它们通常会导致严重的疾病，导致儿童和成人严重残疾并缩短寿命。不幸的是，目前还没有有效的治疗方法可以阻止或逆转疾病的进展。一类新兴但特征不明的线粒体疾病与磷脂代谢受损有关。心磷脂 (CL) 是一种仅存在于线粒体膜中的磷脂 (PL)，具有多种重要的线粒体功能。 CL 生物合成是一个复杂的过程，涉及内质网 (ER)、细胞质内与核膜相连的膜小管网络和线粒体。然而，它最终是由线粒体内膜 (IMM) 内的磷脂酸 (PA) 合成的。 PA 从 ER 转移到 IMM 的关键是 TRIAP1-PRELID1 复合物。最近出现了有关 ER 和线粒体之间内在联系的进一步证据，有证据表明 mtDNA 复制发生在 ER-线粒体接触位点，从而将 mtDNA 合成和线粒体分裂耦合起来。然而，将 mtDNA 合成与线粒体分裂联系起来的机制，以及受干扰的 ER-线粒体接触位点对 mtDNA 复制的影响，仍然知之甚少。我在国家神经内科和神经外科医院帮助管理的 NHS 线粒体疾病高度专业服务中发现了一名患者，该患者患有第一个致病性突变（导致 人类 TRIAP1 基因中的蛋白质移码），其蛋白质产物对于 CL 生物合成至关重要。我进行了详细的研究，发现患者来源的成纤维细胞和肌肉组织中存在 CL 代谢受损和 mtDNA 复制异常的情况。这一新发现支持了磷脂稳态在 mtDNA 维持中的重要性，并为增进对线粒体生物学基本方面的理解提供了重要机会。我的奖学金的总体研究目标是更深入地了解 CL 代谢如何影响 mtDNA 合成和线粒体分裂。主要目标是：1) 描述受干扰的 CL 代谢如何影响 mtDNA 复制和线粒体分裂； 2) 定义 TRIAP1 相互作用组并鉴定 CL 生物合成和 PL 运输所需的新蛋白质； 3) 研究肌肉特异性 CL 生物合成和 PL 运输途径。这些目标将通过研究以下细胞模型中的 CL 代谢和 PL 运输途径来实现：突变和敲除 (KO) TRIAP1 成纤维细胞；使用细胞生物学和蛋白质组学相结合的方法，突变 TRIAP1 人类诱导多能干细胞 (hiPSC) 衍生的成肌细胞。该研究将在世界领先的神经科学中心伦敦大学学院神经病学研究所进行，并与以下机构合作：剑桥大学 MRC 线粒体生物学中心（Massimo Zeviani 教授），国际公认的线粒体生物学和医学研究卓越中心；以及科隆大学衰老相关疾病细胞应激反应卓越集群（托马斯·兰格教授），欧洲领先的线粒体生物学和衰老研究机构。

项目成果

Utility of Whole Blood Thiamine Pyrophosphate Evaluation in TPK1-Related Diseases

• DOI: 10.3390/jcm8070991
• 发表时间: 2019-07-01
• 期刊: JOURNAL OF CLINICAL MEDICINE
• 影响因子: 3.9
• 作者: Bugiardini, Enrico;Pope, Simon;Pitceathly, Robert D. S.
• 通讯作者: Pitceathly, Robert D. S.

Comment on "A severe linezolid-induced rhabdomyolysis and lactic acidosis in Leigh syndrome".

评论“Leigh 综合征中利奈唑胺诱发的严重横纹肌溶解症和乳酸性酸中毒”。

• DOI: 10.1002/jimd.12329
• 发表时间: 2021
• 期刊: Journal of inherited metabolic disease
• 影响因子: 4.2
• 作者: Bindoff LA

Advances in methods to analyse cardiolipin and their clinical applications.

• DOI: 10.1016/j.trac.2022.116808
• 发表时间: 2022-12
• 期刊: Trends in analytical chemistry : TRAC
• 作者: Bautista JS;Falabella M;Flannery PJ;Hanna MG;Heales SJR;Pope SAS;Pitceathly RDS
• 通讯作者: Pitceathly RDS

Self-reported postural symptoms predict vestibular dysfunction and falls in patients with multi-sensory impairment.

自我报告的姿势症状可预测多感觉障碍患者的前庭功能障碍和跌倒。

• DOI: 10.1007/s00415-021-10921-y
• 发表时间: 2022
• 期刊: Journal of neurology
• 影响因子: 6
• 作者: Bennett E