Mitochondrial metabolism and the Lon-PDH axis

线粒体代谢和 Lon-PDH 轴

• 批准号: 10728404
• 负责人: CAROLYN K SUZUKI
• 金额: $ 7.73万
• 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/10728404
• 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蛋白水解酶是线粒体蛋白平衡的主要调节者，线粒体蛋白稳定是 调节线粒体能量代谢，缓解细胞应激。我们最近确定了一部小说 两个神经系统疾病严重的同胞中编码LON的LONP1基因的致病变异 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)。这些兄弟姐妹的原代皮肤成纤维细胞显示，丙酮酸的活性 脱氢酶(PDH)显著降低。PDH缺乏的原因是Lon-P761L不能降解PDH的磷酸化E1a亚单位，该亚单位积聚并抑制PDH 活动。PDH是连接糖酵解和三羧酸(TCA)循环的中央守门人，它是 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 Lon-P761L纯合子表达会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。神经元几乎完全由葡萄糖产生三磷酸腺苷 氧化，因此全功能的PDH活性是至关重要的。相比之下，星形胶质细胞具有更广泛的新陈代谢 乳酸、谷氨酰胺和酮体的容量和供应神经元，这些小体用于形成乙酰基 葡萄糖氧化所需的辅酶A和三氯乙酸循环中间体。我们假设野生型Lon 调节PDH复合体的结构和活动，并调节上游和下游 效应器，以校准线粒体新陈代谢和能量学。在这个项目中，我们将使用患者和父母来源的成纤维细胞，以及已经被重新编程以产生诱导的成纤维细胞 多能干细胞(IPSCs)。这些IPSCs将分化为神经元和星形胶质细胞。vbl.使用 患者和父母来源的成纤维细胞，Aim 1将测试Lon介导的降解的假设 调节PDH复合体的结构和活性。目标2将确定上行和下行 Lon-PDH轴的调节器，在表达野生型Lon和Lon-P761L的细胞中发生变化。 在目标3中，我们将研究Lon对IPSCs分化为神经元和 星形胶质细胞。我们的研究将建立新的Lon依赖的分子机制 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。 (例如，PDK、PDP、LON)，增加PDH活性的药理和饮食干预和/或 治疗PDH缺乏症合并Lon功能障碍。这些结果对以下方面有更广泛的影响 了解PDH活性和线粒体代谢如何在罕见和更多的患者中得到校准 常见疾病，如心脏病、癌症和神经退行性变。