Synaptic Dysfunction Affecting DNA Integrity in Alzheimer's Disease

影响阿尔茨海默病 DNA 完整性的突触功能障碍

基本信息

批准号：
8665337
负责人：
Lennart Mucke
金额：
$ 45.23万
依托单位：
J. DAVID GLADSTONE INSTITUTES
依托单位国家：
美国
项目类别：
财政年份：
1992
资助国家：
美国
起止时间：
1992-09-01 至 2018-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8665337
关键词：
Abbreviations Acids Adrenal Glands Adverse effects Affect Alzheimer&apos s Disease Aminobutyric Acids Amyloid beta-Protein Amyloid beta-Protein Precursor Antiepileptic Agents Apolipoproteins Autopsy Award BRCA1 gene Behavior Brain Brain region C-terminal Chromatin Cognitive deficits Cyclic AMP-Responsive DNA-Binding Protein DL-TBOA DNA DNA Damage DNA Double Strand Break DNA Modification Process DNA Repair DNA Sequence DNA Sequence Analysis Dementia Disease Double Effect Drug Kinetics Elderly Electroencephalography Ensure Environment EphB2 Receptor Excitatory Amino Acids Exposure to Free Radicals Frontotemporal Dementia Functional disorder Funding GLAST Protein Gene Expression Genes Genetic Genome Glial Fibrillary Acidic Protein Glutamate Receptor Glutamate Transporter Glutamates Glycoproteins Grant Growth Histones Hour Human Hypothalamic structure Immunohistochemistry Impairment In Vitro Learning Levetiracetam Long-Term Potentiation MAP Kinase Gene Massive Parallel Sequencing Meiotic Recombination Memory Mitogen-Activated Protein Kinases Mus N-Methylaspartate Nature Nerve Degeneration Neuron-Specific Enolase Neuronal Dysfunction Neurons Nuclear Pathogenesis Patients Peer Review Pharmaceutical Preparations Pharmacodynamics Phosphate Buffer Physiological Pituitary Gland Polymerase Chain Reaction Process Productivity Progress Reports Protein phosphatase Proteins Publications Reactive Oxygen Species Regulation Request for Applications Research Resistance Saline Simulate Stress Synapses Synaptic Vesicles Testing Therapeutic Time Transgenic Mice Transgenic Organisms Variant ataxia telangiectasia mutated protein benzyloxyaspartate brain tissue cancer type chromatin immunoprecipitation cognitive function cost dentate gyrus dihydroethidium endonuclease entorhinal cortex familial Alzheimer disease gamma-Aminobutyric Acid human 53BP1 protein improved in vivo innovation malignant breast neoplasm mild cognitive impairment mouse model mutant nervous system disorder network dysfunction neuropeptide Y novel postsynaptic presenilin-1 presynaptic prevent public health relevance repaired response small hairpin RNA synaptic function tau Proteins

项目摘要

DESCRIPTION (provided by applicant): This grant focuses on Alzheimer's disease (AD), the most frequent neurodegenerative condition, and on the question of how elevation of amyloid-beta (A-beta) levels in the brain contributes to its pathogenesis. Recently, we discovered that exploration of a novel environment causes putative DNA double strand breaks (DSBs) in neurons of wildtype (WT) mice. The DSBs were most abundant in memory centers and were repaired within 24 hours. Transgenic mice with neuronal expression of familial AD-mutant forms of the human amyloid precursor protein (hAPPFAD mice), which simulate several aspects of AD, had increased neuronal DSBs at baseline and more severe and prolonged DSBs after exploration. Treatment with the anti-epileptic drug levetiracetam suppressed aberrant network activity, normalized levels of DSBs and improved synaptic functions as well as learning and memory in hAPPFAD mice. In primary neuronal cultures from WT mice, exposure to human A-beta oligomers increased DSBs, and this effect was prevented by blocking NR2B-containing NMDA-type glutamate receptors. Thus, A-beta may exacerbate and prolong activity-related increases in neuronal DSBs, possibly as a result of synaptic and network dysfunction. By changing the expression of genes involved in cognitive functions and the regulation of neuronal activities, this process could promote a vicious cycle and contribute to the pathogenesis of AD. To test these hypotheses, we will (1) further characterize the nature and causes of neuronal DSBs in WT and hAPP-J20 mice, (2) determine the mechanisms by which levetiracetam counteracts A-beta-induced increases in neuronal DSBs, (3) determine whether neuronal DSBs and the associated histone variant YH2A.X specifically affect learning/memory and related gene expression, and (4) validate key findings in other mouse models and in humans with AD. The most novel aspects of this proposal include the hypotheses that physiological brain activity causes transient neuronal DSBs that DNA integrity in neurons is regulated by the activity of NR2B-containing glutamate receptors, and that pathologically elevated levels of A-beta alter these processes by changing the activities of synapses and neuronal networks. Innovative approaches include the use of chromatin immunoprecipitation and massively parallel DNA sequencing to identify the genes affected and the use of a novel APP knockin mouse that overproduces A¿ but not APP. Investigational anti-A-beta treatments have been associated with serious side effects that were probably unrelated to the reduction of A-beta levels per se. It is therefore desirable to identify alternative or complementary therapeutic strategies to make the brain more resistant to A-beta-induced neuronal dysfunction. Protecting the neuronal genome against A-beta's adverse effects could be particularly critical in this regard.

描述（由申请人提供）：这项资助的重点是阿尔茨海默病（AD），这是最常见的神经退行性疾病，以及大脑中淀粉样蛋白（A-β）水平的升高如何促进其发病机制的问题。我们发现，探索新环境会导致野生型 (WT) 小鼠神经元中假定的 DNA 双链断裂 (DSB)，DSB 在记忆中心最为丰富，并在 24 小时内修复。神经表达人类淀粉样前体蛋白家族性 AD 突变形式的转基因小鼠（hAPPFAD 小鼠）模拟了 AD 的多个方面，在基线时神经元 DSB 增加，在探索抗癫痫药物治疗后，DSB 更严重且延长。在来自 WT 小鼠的原代神经元培养物中，药物左乙拉西坦抑制了 hAPPFAD 小鼠的异常网络活动、使 DSB 水平正常化并改善了突触功能以及学习和记忆。人类 A-β 寡聚物增加了 DSB，而这种效应可以通过阻断含有 NR2B 的 NMDA 型谷氨酸受体来阻止。因此，A-β 可能会加剧和延长神经元 DSB 的活动相关增加，这可能是突触和网络的结果。通过改变参与认知功能和神经元活动调节的基因表达，这一过程可能会促进恶性循环并促进 AD 的发病机制。 (1) 进一步表征 WT 和 hAPP-J20 小鼠中神经元 DSB 的性质和原因，(2) 确定左乙拉西坦抵消 A-β 诱导的神经元 DSB 增加的机制，(3) 确定神经元 DSB 是否与相关的神经元 DSB 相关。组蛋白变体 YH2A.X 特别影响学习/记忆和相关基因表达，并且 (4) 验证其他小鼠模型和患有 AD 的人类的关键发现。该提案最新颖的方面包括假设。生理性大脑活动会导致短暂的神经元 DSB，神经元中的 DNA 完整性受含有 NR2B 的谷氨酸受体的活性调节，病理性升高的 A-β 水平通过改变突触和神经元网络的活动来改变这些过程。使用染色质免疫沉淀和大规模并行 DNA 测序来识别受影响的基因，并使用可过量产生 A¿ 的新型 APP 敲入小鼠但研究性抗 A-β 治疗与严重的副作用相关，这些副作用可能与 A-β 水平本身的降低无关，因此需要确定替代或补充治疗策略以使大脑更具抵抗力。保护神经元基因组免受 A-β 的不利影响在这方面尤其重要。