Mitochondrial metabolism and the Lon-PDH axis

线粒体代谢和 Lon-PDH 轴

• 批准号: 10594025
• 负责人: CAROLYN K SUZUKI
• 金额: $ 32.17万
• 依托单位: RUTGERS BIOMEDICAL AND 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: 2020-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10594025
• 关键词: ATP Synthesis Pathway; Acetyl Coenzyme A; Acetylation; Animal Model; Architecture; Astrocytes; Atrophic; Brain; Calibration; Carbohydrates; Catabolism; Cells; Cellular Stress; Cerebrum; Citric Acid Cycle; Complex; Data; Defect; Dietary Intervention; Disease; Energy Metabolism; Energy-Generating Resources; Enzyme Inhibition; Erythrocytes; Failure; Fatty Acids; Fibroblasts; Functional disorder; Gatekeeping; Generations; Genes; Glucose; Glutamine; Glycolysis; Glycolysis Inhibition; Goals; Heart Diseases; Human; Impairment; Investigation; Ketone Bodies; Knowledge; Leucine; Link; Malignant Neoplasms; Measures; Mediating; Medium chain fatty acid; Metabolic; Metabolism; Missense Mutation; Mitochondria; Modeling; Modification; Molecular; Molecular Machines; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neurologic; Neurologic Dysfunctions; Neurons; Outcome; Oxidative Phosphorylation; PDH kinase; Parents; Pathogenicity; Pathway interactions; Patients; Phosphorylation; Positioning Attribute; Post-Translational Protein Processing; Production; Proline; Protein Dephosphorylation; Proteins; Proteolysis; Proteomics; Pyruvate; Pyruvate Dehydrogenase (Lipoamide)-Phosphatase; Pyruvate Dehydrogenase Complex; Pyruvate Dehydrogenase E1; Reaction; Regulation; Siblings; Skin; Sterol O-Acyltransferase; Testing; Transcript; Variant; Work; amino acid metabolism; brain cell; dihydrolipoamide dehydrogenase; dihydrolipoyllysine-residue acetyltransferase; endopeptidase La; experimental study; fatty acid oxidation; high throughput screening; induced pluripotent stem cell; intermolecular interaction; metabolomics; mitochondrial metabolism; mutant; novel; oxidation; pharmacologic; programs; proteostasis; pyruvate dehydrogenase; response; stem cell differentiation; therapeutic protein; uptake

The human Lon protease is a master regulator of mitochondrial proteostasis, which is essential for regulating mitochondrial energy metabolism and mitigating cell stress. We recently identified a novel pathogenic variant in the LONP1 gene encoding Lon, in two siblings with profound neurologic impairment, cerebral and cerebellar atrophy, in which proline at position 761 was replaced by leucine (Lon-P761L). Primary skin fibroblasts from these siblings, showed that the activity of pyruvate dehydrogenase (PDH) was substantially reduced. PDH deficiency was caused by the failure of Lon-P761L to degrade the phosphorylated E1a subunit of PDH, which accumulates and inhibits PDH activity. PDH is the central gatekeeper linking glycolysis to the tricarboxylic acid (TCA) cycle, and is also a key regulatory node for glucose and fatty acid catabolism. Our long term goal is to elucidate why homozygous Lon-P761L expression causes severe neurologic dysfunction and neurodegeneration. Glucose is the brain’s principal source of energy. Neurons generate ATP almost exclusively by glucose oxidization, thus fully functional PDH activity is crucial. Astrocytes by contrast, have broader metabolic capacity and supply neurons with lactate, glutamine and ketone bodies, which are used to form acetyl CoA and TCA cycle intermediates required for glucose oxidation. We hypothesize that wild type Lon regulates the architecture and activities of the PDH complex, and modulates upstream and downstream effectors, to calibrate mitochondrial metabolism and energetics. In this project, we will employ patient-and parent-derived fibroblasts, and also fibroblasts that have been reprogrammed to generate induced pluripotent stem cells (iPSCs). These iPSCs will be differentiated into neurons and astrocytes. Using the patient- and parent- derived fibroblasts, Aim 1 will test the hypothesis that Lon-mediated degradation regulates the architecture and activity of the PDH complex. Aim 2 will identify the up- and down-stream modulators of the Lon-PDH axis, which are altered in cells expressing wild type Lon versus Lon-P761L. In Aim 3, we will investigate the regulation of PDH by Lon in iPSCs differentiated into neurons and astrocytes. Our investigation will establish new molecular mechanisms for the Lon-dependent regulation of PDH. The knowledge gained will also help to identify potential therapeutic protein targets (e.g. PDK, PDP, Lon), pharmacologic and dietary interventions for increasing PDH activity and/or for treating PDH deficiency associated with Lon dysfunction. These outcomes have a broader impact for understanding how PDH activity and mitochondrial metabolism can be calibrated in both rare and more common disorders such as heart disease, cancer and neurodegeneration.

人类lon蛋白酶是线粒体蛋白质的主要调节剂，这对于 调节线粒体能量代谢和减轻细胞应激。我们最近确定了一本小说 LONP1基因的致病变异，编码LON，在具有深刻神经系统的两个兄弟姐妹中 损伤，大脑和小脑萎缩，其中761位的脯氨酸被亮氨酸取代 （LON-P761L）。这些兄弟姐妹的一级皮肤成纤维细胞，表明丙酮酸的活性 脱氢酶（PDH）大大降低。 PDH缺乏症是由LON-P761L失败引起的，无法降解PDH的磷酸化的E1A亚基，后者积累并抑制PDH 活动。 PDH是将糖酵解与三核酸（TCA）周期联系起来的中央守门人，IS 也是葡萄糖和脂肪酸分解代谢的关键调节节点。我们的长期目标是阐明为什么 纯合LON-P761L表达会引起严重的神经功能障碍和神经变性。 葡萄糖是大脑的主要能源。神经元几乎完全由葡萄糖产生ATP 氧化，因此功能齐全的PDH活性至关重要。相比之下，星形胶质细胞具有更广泛的代谢 用乳酸，谷氨酰胺和酮体的容量和供应神经元，用于形成乙酰基 COA和TCA循环中间体需要葡萄糖氧化。我们假设野生型LON 调节PDH复合体的架构和活动，并调节上游和下游 效应子，校准线粒体代谢和能量学。在这个项目中，我们将采用患者和父母衍生的成纤维细胞，以及已重编程以生成诱导的成纤维细胞 多能干细胞（IPSC）。这些IPSC将分为神经元和星形胶质细胞。使用 患者和父母衍生的成纤维细胞，AIM 1将检验LON介导降解的假设 调节PDH复合物的结构和活动。 AIM 2将确定上流和下游 LON-PDH轴的调节剂，在表达野生型LON与LON-P761L的细胞中发生了变化。 在AIM 3中，我们将调查LON在IPSC中对PDH的调节，这些调节分化为神经元，并 我们的投资将建立依赖LON的新分子机制 PDH的调节。获得的知识还将有助于确定潜在的治疗蛋白靶标 （例如PDK，PDP，LON），用于增加PDH活性和/或用于增加的药物和饮食干预措施 治疗与LON功能障碍相关的PDH缺乏。这些结果对 了解PDH活性和线粒体代谢如何在稀有和更多中校准 常见疾病，例如心脏病，癌症和神经变性。