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Lon蛋白酶是线粒体蛋白质稳态的主要调节剂，其对于维持线粒体的蛋白质稳态是必需的。 调节线粒体能量代谢，缓解细胞应激。我们最近发现了一本小说 编码Lon的LONP 1基因的致病性变异，在两个患有严重神经系统疾病的兄弟姐妹中 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）。来自这些兄弟姐妹的原代皮肤成纤维细胞，显示丙酮酸的活性 脱氢酶（PDH）的活性显著降低。PDH缺陷是由于Lon-P761 L不能降解磷酸化的PDH的E1 a亚基，从而积累和抑制PDH 活动PDH是连接糖酵解与三羧酸（TCA）循环的中心看门人， 也是葡萄糖和脂肪酸催化剂的关键调节节点。我们的长期目标是阐明为什么 纯合Lon-P761 L表达导致严重的神经功能障碍和神经变性。 葡萄糖是大脑的主要能量来源。神经元几乎完全通过葡萄糖产生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 容量和供应神经元乳酸，谷氨酰胺和酮体，用于形成乙酰 葡萄糖氧化所需的CoA和TCA循环中间体。我们假设野生型Lon 调节PDH复合物的结构和活性，并调节上游和下游 效应器，以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来源的成纤维细胞，以及已经重新编程以产生诱导的成纤维细胞。 多能干细胞（iPSC）。这些iPSC将分化为神经元和星形胶质细胞。使用 患者和亲本来源的成纤维细胞，目的1将检验Lon介导的降解 调节PDH复合物的结构和活性。目标2将确定上游和下游 Lon-PDH轴的调节剂，其在表达野生型Lon的细胞中相对于Lon-P761 L发生改变。 在目标3中，我们将研究Lon在分化为神经元的iPSC中对PDH的调节， 星形胶质细胞我们的研究将建立新的分子机制， PDH的调节。所获得的知识也将有助于确定潜在的治疗蛋白质靶点 (e.g. PDK、PDP、Lon）、用于增加PDH活性和/或用于 治疗与Lon功能障碍相关的PDH缺乏症。这些成果对以下方面产生了更广泛的影响： 了解PDH活性和线粒体代谢如何在罕见和更多的情况下进行校准， 常见的疾病，如心脏病、癌症和神经退化。