权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

TBCK Encephaloneuronopathy: establishing the role of mitochondrial dysfunction in promoting neurodegeneration

TBCK 脑神经病：确定线粒体功能障碍在促进神经退行性变中的作用

基本信息

批准号：
9977429
负责人：
XILMA R ORTIZ-GONZALEZ
金额：
$ 19.19万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
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：
2020-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9977429
关键词：
Address Affect Age Atrophic Automobile Driving Autophagocytosis Biogenesis Biological Biological Assay Biology Brain Branched-Chain Amino Acids CRISPR/Cas technology Child Childhood Clinical Co-Immunoprecipitations Complex DNA copy number Data Disease Disease model Down-Regulation Encephalopathies Environment Epilepsy FRAP1 gene Face Fibroblasts Fishes Frameshift Mutation Functional disorder Future Genes Genetic Diseases Genotype Glycoprotein Degradation Pathway Goals Homidium Bromide Human Impairment In Situ Independent Scientist Award Intellectual functioning disability Label Lead Learning Leucine Measures Mitochondria Mitochondrial DNA Modeling Motor Neurons Mutation NADH Names Nerve Degeneration Nervous System Physiology Neurodegenerative Disorders Neurologic Neurologic Symptoms Neurons Neurosciences Pathway interactions Patients Phenotype Phosphotransferases Physicians Physiological Play Positioning Attribute Protein Kinase Proteins Proteomics Puerto Rican Quality Control Reporting Research Respiration Respiratory Chain Role Scientist Seizures Severities Signal Transduction Spinal Muscular Atrophy Symptoms Syndrome Techniques Testing Therapeutic Training Treatment Efficacy Work Zebrafish autism spectrum disorder autistic clinical Diagnosis experimental study fluorescence lifetime imaging gene replacement in vivo induced pluripotent stem cell insight loss of function mitochondrial dysfunction nervous system disorder neurodegenerative phenotype neurogenetics neuromuscular new therapeutic target novel novel therapeutics null mutation overexpression programs protein expression protein protein interaction tool vector

项目摘要

PROJECT SUMMARY Autosomal recessive mutations in the TBCK gene cause intellectual disability of variable severity. I have further characterized the neurologic phenotype of Puerto Rican children with a homozygous null mutation (p.R126X) in TBCK, which we designated the Boricua mutation. The biological mechanism underlying the genotype-phenotype correlations remain unclear. On one extreme, patients with the severe Boricua mutation develop progressive brain, cerebellar and motor neuron atrophy, coarse facial features and epilepsy. We named this severe syndrome TBCK-encephaloneuronopathy (TBCKE). On the other hand, other patients with biallelic TBCK mutations have clinical diagnosis of autism and/or intellectual disability, without evidence of neurodegeneration. The function of TBCK protein is unknown, but previous studies have shown absence of TBCK leads to downregulation of mTORC1 signaling. The mTORC1 pathway regulates autophagy, including the targeted degradation of mitochondria (mitophagy). I recently reported increased autophagic flux and impaired glycoprotein degradation in TBCKE patients’ fibroblasts, which was rescued by activating mTORC1 signaling with L-leucine. Our fibroblasts studies suggests that TBCKE patients have mitochondrial dysfunction and mitochondrial DNA (mtDNA) depletion. Furthermore, the degree of mtDNA depletion predicts the neurologic severity of TBCK disease. Therefore, I hypothesize that loss of function of TBCK in human neurons leads to mtDNA depletion and mitochondrial dysfunction due to excessive autophagic clearance of mitochondria. To test this hypothesis in more disease relevant models, I propose to generate TBCK-null induced pluripotent stem cell (iPSC) derived neurons (iNeu) and tbck-/- zebrafish. The goal of this proposal is to address whether loss of function of TBCK affects mitochondrial function in human neurons, and to determine whether mtDNA depletion modulates the severity of neurodegeneration in TBCK disease. Using novel disease models and unique tools to assay mitochondrial function, I propose to address the following questions: (Aim 1) Do human neurons lacking TBCK protein have excessive mitophagy? (Aim2) What is the function of TBCK? Can we define its protein-protein interactions in neurons? (Aim 3) Can TBCK- null zebrafish model the variable severity of TBCK disease? Can mtDNA depletion modulate the severity of the phenotype in vivo? The experiments outlined in this proposal will determine the role of mitochondria in TBCKE and whether mtDNA depletion is sufficient to drive the neurodegenerative phenotype or merely an epiphenomenon. This work will also provide training in novel techniques for assaying neuronal mitochondrial function in disease models in situ. I will also learn to develop and characterize zebrafish models of neurodevelopmental disease. Support from this K02 award will be instrumental in growing my independent research program as a physician scientist in a superb institutional environment towards my long-term goal of studying the role of mitochondrial dysfunction in pediatric neurodegenerative disorders.

项目概要 TBCK 基因的常染色体隐性突变会导致不同严重程度的智力障碍。我有进一步表征了具有纯合无效突变的波多黎各儿童的神经表型 (p.R126X) 位于 TBCK 中，我们将其命名为 Boricua 突变。其背后的生物学机制基因型与表型的相关性仍不清楚。一种极端情况是，患有严重 Boricua 突变的患者出现进行性大脑、小脑和运动神经元萎缩、面部特征粗糙和癫痫。我们将这种严重综合征命名为 TBCK-脑神经病 (TBCKE)。另一方面，其他患者双等位基因 TBCK 突变具有自闭症和/或智力障碍的临床诊断，但没有证据表明神经变性。 TBCK蛋白的功能尚不清楚，但之前的研究表明TBCK蛋白的功能不存在 TBCK 导致 mTORC1 信号传导下调。 mTORC1 通路调节自噬，包括线粒体的定向降解（线粒体自噬）。我最近报告自噬通量增加 TBCKE 患者成纤维细胞中糖蛋白降解受损，可通过激活 mTORC1 来挽救 L-亮氨酸信号传导。我们的成纤维细胞研究表明 TBCKE 患者存在线粒体功能障碍和线粒体 DNA (mtDNA) 耗竭。此外，mtDNA 耗竭的程度预示着 TBCK 疾病的神经系统严重程度。因此，我推测人类神经元中 TBCK 功能的丧失由于过度自噬清除，导致 mtDNA 耗竭和线粒体功能障碍线粒体。为了在更多疾病相关模型中测试这个假设，我建议生成 TBCK-null 诱导多能干细胞 (iPSC) 衍生的神经元 (iNeu) 和 tbck-/- 斑马鱼。该提案的目标是解决 TBCK 功能丧失是否影响人类神经元线粒体功能的问题，并确定 mtDNA 耗竭是否会调节 TBCK 疾病神经退行性变的严重程度。我建议使用新的疾病模型和独特的工具来测定线粒体功能以下问题：（目标 1）缺乏 TBCK 蛋白的人类神经元是否存在过度线粒体自噬？（目标2） TBCK的作用是什么？我们能否定义其在神经元中的蛋白质-蛋白质相互作用？（目标 3）可以 TBCK- null 斑马鱼模型 TBCK 疾病的不同严重程度？ mtDNA 耗竭可以调节疾病的严重程度吗？体内表型？本提案中概述的实验将确定线粒体在 TBCKE 中的作用以及 mtDNA 耗尽是否足以驱动神经退行性表型或仅仅是一种附带现象。这项工作还将提供检测神经元线粒体新技术的培训在疾病模型中的原位功能。我还将学习开发和表征斑马鱼模型神经发育疾病。 K02 奖项的支持将有助于我的独立发展作为一名医师科学家，在一流的机构环境中进行研究计划，以实现我的长期目标研究线粒体功能障碍在儿科神经退行性疾病中的作用。