Mitochondrial metabolism and the Lon-PDH axis

线粒体代谢和 Lon-PDH 轴

基本信息

批准号：
10379257
负责人：
CAROLYN K SUZUKI
金额：
$ 32.17万
依托单位：
RBHS-NEW JERSEY MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10379257
关键词：
Acetyl Coenzyme A Acetylation Animal Model Architecture Astrocytes Atrophic Brain Carbohydrates Catabolism Cells Cellular Stress Cerebrum Citric Acid Cycle Complex Data Defect Dietary Intervention Disease Energy Metabolism Energy-Generating Resources Enzymes 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 Modification Molecular Molecular Machines Mutation Nerve Degeneration Neurodegenerative Disorders Neurologic Neurologic Dysfunctions Neurons Outcome Oxidative Phosphorylation Oxides PDH kinase Parents Pathogenicity Pathway interactions Patients Pharmacology Phosphorylation Positioning Attribute Post-Translational Protein Processing Production Proline Proteins Proteolysis Proteomics Pyruvate Pyruvate Dehydrogenase (Lipoamide)-Phosphatase Pyruvate Dehydrogenase Complex Pyruvate Dehydrogenase E1 Reaction Regulation Siblings Skin Stream 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 proteostasis pyruvate dehydrogenase response stem cell differentiation therapeutic protein uptake

项目摘要

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稳态的主要调节因子，对于维持线粒体功能至关重要。我们最近发现了一种新的方法来调节线粒体能量代谢和减轻细胞应激。两个患有严重神经系统疾病的兄弟姐妹中编码 Lon 的 LONP1 基因的致病性变异损伤、大脑和小脑萎缩，其中 761 位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) 显着降低是由于 Lon-P761L 未能降解 PDH 的磷酸化 E1a 亚基，从而积累并抑制 PDH。 PDH 是将糖酵解与三羧酸 (TCA) 循环联系起来的中心看门人。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原因。纯合 Lon-P761L 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 ATP。相比之下，星形胶质细胞具有更广泛的氧化作用，因此功能齐全的 PDH 活性至关重要。能力并为神经元提供乳酸、谷氨酰胺和酮体，这些物质用于形成乙酰基葡萄糖氧化所需的 CoA 和 TCA 循环中间体，我们勇敢地使用野生型 Lon。调节 PDH 复合体的结构和活动，并调节上游和下游在这个项目中，我们将使用患者和亲本来源的成纤维细胞，以及经过重新编程以产生诱导的成纤维细胞。多能干细胞 (iPSC) 将分化为神经元和星形胶质细胞。患者和亲本来源的成纤维细胞，目标 1 将检验 Lon 介导的降解的假设调节 PDH 复合体的结构和活性目标 2 将识别上游和下游。 Lon-PDH 轴的调节剂，与表达野生型 Lon 的细胞相比，表达 Lon-P761L 的细胞中的调节剂发生改变。在目标 3 中，我们将研究分化为神经元和神经元的 iPSC 中 Lon 对 PDH 的调节。我们的研究将为 Lon 依赖性建立新的分子机制。获得的知识也将有助于识别潜在的治疗蛋白靶点。（例如 PDK、PDP、Lon）、药物和饮食干预以增加 PDH 活性和/或治疗与 Lon 功能障碍相关的 PDH 缺乏症这些结果对患者具有更广泛的影响。了解如何在罕见和更多情况下校准 PDH 活性和线粒体代谢常见疾病，如心脏病、癌症和神经退行性疾病。