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（应用程序提供）：本研究将探讨以下假说：cAMP反应元件结合蛋白（CREB） - 一种转录因子 - 中枢神经系统中具有潜水功能的转录因子，以及代谢调节构成对线粒体缺陷的贡献，并通过ataxia-telangiectia syten（a apenten）疾病（ROS）形成的线粒体缺陷和病理反应性氧气（ATENAXIA-TELANGICIA）（A-TENAXIA-TENECEN）（A-TENAXIA-TEREN），一种Neyurangiectasia（A-T），一种TNE-T），一种TNE-T），一种TNE-T），一种TNE-T），一种TNE-T），一种TNE-T）基因。 ATM在DNA双链断裂的信号传导和修复中编码具有工具作用的蛋白激酶，DNA双链断裂是一种高度致癌的DNA损伤。 ATM还被认为在线粒体稳态和抑制有毒ROS中起着重要作用。但是，ATM功能的这一方面知之甚少。在已发表的工作中，我们表明，ATM磷酸化在保守的SER簇上磷酸化，这会响应DNA损伤和其他形式的细胞应激，从而减弱CREB反式激活潜力。对该提案的重要性非常重要，最近的一项独立研究表明，核心核心NCOR1代表了大量具有线粒体功能的CREB靶基因。在这里，我们将探讨ATM，CREB和NCOR1在严重衰减线粒体功能和ROS产生的常见途径中功能，以响应DNA损伤和氧化应激。具体而言，我们建议ATM介导的CREB磷酸化募集NCOR1以使线粒体靶基因沉默。该假设与A-T的相关性是，有缺陷的CREB磷酸化可能导致线粒体缺陷和有助于神经元损伤的氧化应激。我们将使用生化和遗传方法的结合来测试这些思想，包括使用表达突变体Creb等位基因（CREBS111A）难治性的基因靶向小鼠对ATM磷酸化的使用。 CREBS111a小鼠暴露于CREB介导的基因表达的代谢异常和改变，这些小鼠的成纤维细胞和神经元将用于探索NCOR1依赖性CREB衰减的机制。总而言之，拟议的工作将定义ATM介导的CREB磷酸化对转录调控和线粒体稳态的影响。这项工作的结果可能会提供重要的新见解，以了解ATM丢失如何导致A-T中的病理氧化应激。该提案的具体目的是：i）评估Crebs11a小鼠中的ROS，线粒体动力学和小脑基因表达； ii）定义CREB和NCOR1之间的信号和磷酸化依赖性功能关系。