Mechanisms of mitochondrial damage in ataxia-telangiectasia

共济失调毛细血管扩张症线粒体损伤的机制

基本信息

批准号：
9105821
负责人：
Randal Scot Tibbetts
金额：
$ 22.53万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-15 至 2017-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9105821
关键词：
ATM gene ATM wt Allele Alleles Ataxia Telangiectasia Ataxia Telangiectasia Patients Attenuated Behavioral Biochemical Genetics Cell Nucleus Cells Cellular Stress Cerebellum ChIP-on-chip ChIP-seq Chromatin Chronic Cyclic AMP-Responsive DNA-Binding Protein DNA Damage DNA Double Strand Break Data Deacetylase Defect Development Double Strand Break Repair Exhibits Fibroblasts Gene Expression Gene Expression Profile Gene Targeting Generations Genes Genetic Transcription Genotoxic Stress Goals HDAC4 gene Health Hereditary Disease Homeostasis Ionizing radiation Knock-in Knock-in Mouse Lead Light Link Malignant Neoplasms Mammalian Cell Measures Mediating Metabolic Mitochondria Modeling Motor Mus Mutation Nerve Degeneration Nervous System Physiology Nervous system structure Neuraxis Neurodegenerative Disorders Neurologic Neuronal Injury Neurons Nuclear Oncogene Deregulation Oxidative Stress Pathologic Pathology Pathway interactions Performance Phenotype Phosphorylation Physiology Play Predisposition Protein Kinase Publishing Radiation Tolerance Reactive Oxygen Species Recruitment Activity Refractory Regulation Role Signal Transduction Stress Structure Synaptic plasticity Syndrome System Testing Transactivation Transcription Repressor/Corepressor Transcriptional Regulation Work ataxia telangiectasia mutated protein attenuation defined contribution disease-causing mutation genetic approach glucose metabolism insight mutant novel object recognition promoter protein function repaired research study response transcription factor

项目摘要

DESCRIPTION (provided by applicant): This study will explore the hypothesis that hyperactivation of the cAMP response element-binding protein (CREB)-a transcription factor with diverse functions in the central nervous system and metabolic regulation-contributes to mitochondrial defects and pathologic reactive oxygen species (ROS) formation in ataxia-telangiectasia (A-T), a neurodegenerative disease caused by mutations in the ATM gene. ATM encodes a protein kinase with instrumental roles in the signaling and repair of DNA double-strand breaks, a highly carcinogenic form of DNA damage. ATM is also thought to play an important role in mitochondrial homeostasis and suppression of toxic ROS; however this aspect of ATM function is poorly understood. In published work we showed that ATM phosphorylates CREB on a conserved cluster of Ser residues that attenuates CREB transactivation potential in response to DNA damage and other forms of cellular stress. Of importance to this proposal, an independent study recently showed that the nuclear corepressor NCoR1 represses a large number of CREB target genes with mitochondrial function. Here we will explore the idea that ATM, CREB, and NCoR1 function in a common pathway to critically attenuate mitochondrial function and ROS generation in response to DNA damage and oxidative stress. Specifically, we propose that ATM-mediated phosphorylation of CREB recruits NCoR1 to silence mitochondrial target genes. The relevance of this hypothesis for A-T is that defective CREB phosphorylation may engender mitochondrial defects and oxidative stress that contribute to neuronal injury. We will test these ideas using a combination of biochemical and genetic approaches, including the use of gene-targeted mice expressing a mutant CREB allele (CREBS111A) refractory to phosphorylation by ATM. CREBS111A mice exhibit metabolic abnormalities and alterations in CREB- mediated gene expression, and fibroblasts and neurons from these mice will be used to explore the mechanisms of NCoR1-dependent CREB attenuation. In summary, the proposed work will define the impact of ATM-mediated CREB phosphorylation on transcriptional regulation and mitochondrial homeostasis. Results from this work may provide important new insights into how loss of ATM leads pathologic oxidative stress in A-T. The Specific Aims of the proposal are to: i) Assess ROS, mitochondrial dynamics, and cerebellar gene expression in CREBS111A mice; and ii) Define signal and phosphorylation-dependent functional relationships between CREB and NCoR1.

描述（由申请人提供）：本研究将探讨以下假设：cAMP 反应元件结合蛋白（CREB）是一种在中枢神经系统和代谢调节中具有多种功能的转录因子，其过度激活会导致线粒体缺陷和病理性活性氧共济失调毛细血管扩张症（A-T）是一种由 ATM 基因突变引起的神经退行性疾病，ATM 编码一种蛋白激酶，在 DNA 双链的信号传导和修复中发挥重要作用。断裂，一种高度致癌的 DNA 损伤形式，ATM 也被认为在线粒体稳态和抑制有毒 ROS 中发挥着重要作用；然而，我们对 ATM 功能的这一方面知之甚少。 Ser 残基簇可减弱 CREB 反式激活潜力，以响应 DNA 损伤和其他形式的细胞应激，这一建议非常重要，最近的一项独立研究表明，核辅阻遏物 NCoR1 会抑制大量细胞。在这里，我们将探讨 ATM、CREB 和 NCoR1 在共同途径中发挥作用，以响应 DNA 损伤和氧化应激而严重减弱线粒体功能和 ROS 生成。 CREB 介导的磷酸化会招募 NCoR1 来沉默线粒体靶基因。该假设与 A-T 的相关性在于，CREB 磷酸化缺陷可能会导致线粒体缺陷和氧化应激。我们将结合生化和遗传学方法来测试这些想法，包括使用表达突变 CREB 等位基因 (CREBS111A) 的小鼠，该小鼠表现出代谢异常和 CREB- 磷酸化。介导的基因表达，这些小鼠的成纤维细胞和神经元将用于探索 NCoR1 依赖性 CREB 减弱的机制。总之，拟议的工作将定义。 ATM 介导的 CREB 磷酸化对转录调节和线粒体稳态的影响可能为 ATM 缺失如何导致 A-T 中的病理性氧化应激提供重要的新见解。 CREBS111A 小鼠的线粒体动力学和小脑基因表达；以及 ii) 定义 CREB 和 NCoR1 之间的信号和磷酸化依赖性功能关系。