Chromatin Modifications and Vulnerability to Glutamate Toxicity

染色质修饰和谷氨酸毒性脆弱性

基本信息

批准号：
7826976
负责人：
ALEXEI D KONDRATYEV
金额：
$ 23.03万
依托单位：
GEORGETOWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-15 至 2012-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7826976
关键词：
Acute Address Affect Alzheimer&apos s Disease Amyotrophic Lateral Sclerosis Animals Apoptosis Ataxia Ataxia Telangiectasia Brain Cell Death Cells Cessation of life Chronic Clinical Commit Complement DNA DNA Damage DNA Double Strand Break DNA Repair DNA lesion Detection Disease Double Strand Break Repair Foundations Future Generations Glutamate Receptor Glutamates Goals Histones Huntington Disease Impairment Injury Internucleosomal DNA Fragmentation Ischemia Lead Lesion Measures Mediating Mediator of activation protein Modeling Mus N-Methylaspartate Nature Nerve Degeneration Neurodegenerative Disorders Neuroglia Neurologic Neuronal Injury Neurons Oxidative Stress Parkinson Disease Pathology Pathway interactions Phosphorylation Public Health Rattus Reactive Oxygen Species Receptor Activation Resistance Role Seizures Staging Stroke System Testing Therapeutic Intervention Time Toxic effect Transgenic Mice Variant Wild Type Mouse Work anticancer research base cell type chromatin modification endonuclease excitotoxicity histone modification human H2AX protein in vivo nervous system disorder neuron loss neuronal survival neurotoxicity novel public health relevance reconstitution repaired response restoration tumor

项目摘要

DESCRIPTION (provided by applicant): Excessive activation of ionotropic glutamate receptors increases oxidative stress, which contributes to the neurodegeneration observed following neurological insults such as ischemia and seizures, as well as contributes to neuronal death in neurodegenerative diseases (Alzheimer's, Parkinson's, etc.). From a clinical perspective, it is a clear threat to brain function and to survival. It is believed that generation of reactive oxygen species and ensuing oxidative stress is a major contributor to glutamate toxicity. At the same time, oxidative stress is a major cause of DNA damage, which is also a common component of neuronal injury. DNA damage may contribute to neuronal loss and injury not only after acute brain insults but also under various chronic neurodegenerative conditions, such as Alzheimer's, Huntington's, and Parkinson's diseases, amyotrophic lateral sclerosis, ataxia telangiectasia and many other neurological disorders. The most lethal form of DNA damage, the double strand breaks (DSBs), and the ability of cells to repair them has not yet been directly demonstrated following excessive stimulation of glutamate receptors. While limited evidence suggests the importance of DSBs and their repair machinery in vulnerability to glutamate-induced injury, no systematic direct studies have been done in mature neurons. We have developed a sensitive model to start addressing the role of DSB DNA damage in neuronal vulnerability to glutamate-mediated insults using phosphorylation of histone variant H2A.X, which occurs rapidly following DNA DSBs. Our general working hypothesis is that the consequences of unrepaired DSBs in terminally differentiated neurons are critical contributors to neuronal demise in the aftermath of excessive excitation. Conversely, successful repair of these breaks may increase neuronal survival following glutamate-driven insults. Specific Aims will test the following specific hypotheses aiming at proving this concept: 1) Increased phosphorylation of histone H2AX following activation of ionotropic glutamate receptors will result in increased DSB repair; this hypothesis we will tested by measuring DSB repair activity in rat cortical neuronal cultures; 2) Impairment of H2AX phosphorylation will result in increased glutamate toxicity due to the disruption of the DSB repair pathway. To test this, we will examine vulnerability of neurons from H2AX-/- transgenic mice to vulnerability to glutamate toxicity and evaluate their DSB repair capabilities. We expect that H2AX-/- neurons will be more vulnerable to glutamate toxicity and demonstrate diminished DSB repair as compared to wild-type cells. Moreover, we will reconstitute functional histone H2AX in H2AX-/- neurons using lentiviral expression and evaluate the restoration of their resistance to glutamate toxicity. Testing these hypotheses may reveal a novel common mechanism contributing to neurotoxicity in a variety of neurodegenerative disorders, will lead to identification of attractive new targets for therapy of these disorders, and will lay a foundation for future interventional studies in vivo targeting DSB repair pathway in neurons. PUBLIC HEALTH RELEVANCE: Damage to DNA is a common component of neuronal injury. It may contribute to neuronal loss and injury not only after acute brain insult (e.g., prolonged seizures, stroke, TBI) but also under various chronic neurodegenerative conditions, such as Alzheimer's disease, Huntington's disease, Parkinson's disease, amyotrophic lateral sclerosis, ataxia telangiectasia, among other neurological disorders that currently have no effective cure. Excessive excitation also contributes to many of these pathologies and is believed to be the major cause of DNA damage. However, little is known about the mechanisms responsible for the excitation- driven formation of the most lethal type of DNA damage (double strand breaks) in neurons and the ability of nerve cells to withstand this damage. This proposal will examine these mechanisms and will lay the foundation for identification of new targets for therapy of a broad variety of neurological conditions relevant to excitotoxicity.

描述（由申请人提供）：离子型谷氨酸受体的过度激活会增加氧化应激，从而导致缺血和癫痫等神经损伤后观察到的神经变性，并导致神经退行性疾病（阿尔茨海默氏症、帕金森氏症等）中的神经元死亡。。从临床角度来看，它对大脑功能和生存构成明显威胁。据信，活性氧的产生和随之而来的氧化应激是谷氨酸毒性的主要原因。同时，氧化应激是DNA损伤的主要原因，这也是神经元损伤的常见组成部分。 DNA损伤不仅可能导致急性脑损伤后的神经元损失和损伤，而且可能导致各种慢性神经退行性疾病，如阿尔茨海默病、亨廷顿病和帕金森病、肌萎缩侧索硬化症、共济失调性毛细血管扩张症和许多其他神经系统疾病。最致命的 DNA 损伤形式是双链断裂 (DSB)，在过度刺激谷氨酸受体后，细胞修复双链断裂的能力尚未得到直接证实。虽然有限的证据表明 DSB 及其修复机制在谷氨酸诱导损伤中的重要性，但尚未对成熟神经元进行系统的直接研究。我们开发了一个敏感模型，开始利用组蛋白变体 H2A.X 的磷酸化来解决 DSB DNA 损伤在神经元对谷氨酸介导的损伤的脆弱性中的作用，组蛋白变体 H2A.X 的磷酸化在 DNA DSB 后迅速发生。我们的一般工作假设是，终末分化神经元中未修复的 DSB 的后果是过度兴奋后神经元死亡的关键因素。相反，成功修复这些断裂可能会增加谷氨酸驱动的损伤后神经元的存活率。具体目标将测试以下具体假设，旨在证明这一概念：1）离子型谷氨酸受体激活后组蛋白 H2AX 磷酸化增加将导致 DSB 修复增加；我们将通过测量大鼠皮质神经元培养物中的 DSB 修复活性来检验这一假设； 2) H2AX 磷酸化受损将由于 DSB 修复途径的破坏而导致谷氨酸毒性增加。为了测试这一点，我们将检查 H2AX-/- 转基因小鼠的神经元对谷氨酸毒性的脆弱性，并评估其 DSB 修复能力。我们预计，与野生型细胞相比，H2AX-/- 神经元更容易受到谷氨酸毒性的影响，并且 DSB 修复能力减弱。此外，我们将利用慢病毒表达在 H2AX-/- 神经元中重建功能性组蛋白 H2AX，并评估其对谷氨酸毒性的抵抗力的恢复。测试这些假设可能会揭示一种在各种神经退行性疾病中导致神经毒性的新的共同机制，将导致识别出治疗这些疾病的有吸引力的新靶标，并将为未来针对神经元 DSB 修复途径的体内介入研究奠定基础。公共卫生相关性：DNA 损伤是神经元损伤的常见组成部分。它不仅可能在急性脑损伤（例如长期癫痫发作、中风、TBI）后导致神经元损失和损伤，而且可能在各种慢性神经退行性疾病（例如阿尔茨海默病、亨廷顿病、帕金森病、肌萎缩侧索硬化症、共济失调性毛细血管扩张症）下导致神经元损失和损伤。目前尚无有效治疗方法的其他神经系统疾病。过度兴奋也会导致许多此类病症，并被认为是 DNA 损伤的主要原因。然而，人们对神经元中由兴奋驱动形成最致命类型 DNA 损伤（双链断裂）的机制以及神经细胞承受这种损伤的能力知之甚少。该提案将研究这些机制，并为确定治疗与兴奋性毒性相关的多种神经系统疾病的新靶点奠定基础。

项目成果

期刊论文数量（2）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Susceptibility to bystander DNA damage is influenced by replication and transcriptional activity.

旁观者 DNA 损伤的易感性受到复制和转录活性的影响。

DOI：
发表时间：
2012-11-01
期刊：
影响因子：
14.9
作者：
Dickey, Jennifer S;Baird, Brandon J;Redon, Christophe E;Avdoshina, Valeriya;Palchik, Guillermo;Wu, Junfang;Kondratyev, Alexei;Bonner, William M;Martin, Olga A
通讯作者：
Martin, Olga A

Epigenetic regulation of caspase-3 gene expression in rat brain development.

大鼠脑发育过程中 caspase-3 基因表达的表观遗传调控。