Oxidative damage to receptor: G-protein coupling in the aged hippocampus

对受体的氧化损伤：衰老海马中的 G 蛋白偶联

基本信息

批准号：
8122800
负责人：
Joseph Aloysius McQuail
金额：
$ 4.18万
依托单位：
WAKE FOREST UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-08-01 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8122800
关键词：
Acetylcholine Address Affect Age Aging Aging-Related Process Alzheimer&apos s Disease Behavioral Binding Clinical Cognition Cognitive Cognitive aging Complex Coupling Data Denervation Diagnosis Elderly Employee Strikes Exhibits G-Protein-Coupled Receptors GABA Receptor GTP Binding GTP-Binding Protein alpha Subunits, Gi-Go GTP-Binding Proteins Glutamates Goals Hippocampus (Brain)Human Immunoprecipitation Impaired cognition Impairment Individual Individual Differences Investigation Learning Ligands Lipid Peroxidation Location Mass Spectrum Analysis Measures Mediating Memory Memory impairment Metabotropic Glutamate Receptors Modeling Modification Molecular Muscarinic M1 Receptor Muscarinics Neurobiology Neurocognitive Neurons Neurotransmitters Nitrogen Oxidative Stress Oxygen Pharmacologic Substance Play Population Process Proteins Rattus Reactive Oxygen Species Receptor Signaling Relative (related person)Research Research Project Grants Rodent Model Role Route Second Messenger Systems Signal Transduction Site Staining method Stains Synapses Synaptic Receptors System Techniques Testing Therapeutic Therapeutic Intervention Training Work age related aged aging brain aging hippocampus behavioral impairment career cholinergic dentate gyrus experience gamma-Aminobutyric Acid hippocampal subregions improved insight interest nerve supply neuron loss neuropsychological next generation oxidative damage postsynaptic pre-doctoral presynaptic receptor receptor coupling receptor function relating to nervous system research study response second messenger

项目摘要

DESCRIPTION (provided by applicant): Aging is associated with declines in a number of cognitive domains, particularly memory. As people over the age of 65 will comprise more than 20% of the US population by the year 2040, there is a pressing need to elucidate the mechanisms by which aging impairs memory and to identify improved routes of therapeutic intervention. Importantly, neuropsychological assessments of humans demonstrate that not all aged individuals will be clinically diagnosed with memory impairment, demonstrating that chronological and cognitive aging are not synonymous processes. Unlike Alzheimer's disease, age-related changes in memory are not associated with wide-spread neuronal loss; rather there is a selective decrease in the numbers of synapses within the hippocampus and decreased responsivity of post-synaptic receptors. These behavioral and neuronal sequelae apparent in aged humans can be successfully modeled in aged rats tested for memory of spatial locations. This project will make use of a rodent model of aging integrating aspects of chronological and cognitive aging to investigate associated changes in presynaptic and postsynaptic substrates. Parallel analysis of glutamatergic, cholinergic and GABAergic hippocampal circuits and receptors will determine if changes are specific to a particular neurotransmitter system or more general changes in the aged brain. Changes to innervation of the hippocampus will be visualized by immunohistochemical staining techniques and quantified using unbiased stereological approaches. M1 muscarinic- and mGluR5 metabotropic glutmate receptor-mediated GTP-binding, a functional measure of receptor coupling, will be selectively measured using a scintillation proximity counting technique specific to their cognate G-protein 1-subunit, Gq/11. These changes will be contrasted by measures of GABAB receptor-mediated binding which do not deteriorate with age, but signal via a Gi/Go cascade. In the absence of overt loss of receptor and G-proteins, it has been hypothesized that molecular processes associated with oxidative stress in the aged hippocampus may interfere with normal signal transduction. To test this hypothesis, receptors and G-proteins will be analyzed by immunoprecipitation and mass spectrometry to determine if these specific proteins are oxidatively damaged. Collectively, this project will evaluate age-related changes in three neurotransmitter systems closely tied to normal memory function and determine the mechanisms by which these circuits and synapses are changed in aging. The data derived from these experiments will not only greatly enhance understanding of brain aging and cognition, but elucidate changes to specific neural substrates that are of interest for potential therapeutic modulation by the next generation of pharmaceutical treatments. Furthermore, the diversity of experimental approaches proposed to address these focused research efforts will provide for an excellent pre-doctoral training experience to the applicant in support of his stated career goals and objectives. PUBLIC HEALTH RELEVANCE: As people over the age of 65 will comprise more than 20% of the U.S. population by 2040, appreciating the mechanisms by which memory declines in the elderly is matter of pressing scientific and clinical concern. This research project will measure presynaptic and postsynaptic aspects of neural signaling to determine specific changes to metabotropic receptors and G-proteins in the aged hippocampus associated with memory deficits. The findings of this project will enhance our understanding of the aged brain and provide new insights for therapeutic treatment potential.

描述（由申请人提供）：衰老与许多认知领域的衰退有关，尤其是记忆力的衰退。到 2040 年，65 岁以上的人口将占美国人口的 20% 以上，因此迫切需要阐明衰老损害记忆的机制，并找出改进的治疗干预途径。重要的是，对人类的神经心理学评估表明，并非所有老年人都会被临床诊断为记忆障碍，这表明时间老化和认知老化不是同义词过程。与阿尔茨海默病不同，与年龄相关的记忆变化与广泛的神经元丧失无关。相反，海马内的突触数量选择性减少，突触后受体的反应性降低。这些在老年人中明显的行为和神经元后遗症可以在测试空间位置记忆的老年大鼠中成功建模。该项目将利用啮齿动物衰老模型，整合时间和认知衰老的各个方面，以研究突触前和突触后基质的相关变化。对谷氨酸能、胆碱能和 GABA 能海马回路和受体的并行分析将确定这些变化是特定于特定神经递质系统的变化还是老年大脑中更普遍的变化。海马神经支配的变化将通过免疫组织化学染色技术可视化，并使用无偏见的体视学方法进行量化。 M1 毒蕈碱和 mGluR5 代谢型谷氨酸受体介导的 GTP 结合（受体偶联的功能性测量）将使用特定于其同源 G 蛋白 1 亚基 Gq/11 的闪烁邻近计数技术进行选择性测量。这些变化将与 GABAB 受体介导的结合测量形成对比，GABAB 受体介导的结合不会随着年龄的增长而恶化，而是通过 Gi/Go 级联发出信号。在受体和 G 蛋白没有明显丧失的情况下，推测与衰老海马氧化应激相关的分子过程可能会干扰正常的信号转导。为了检验这一假设，将通过免疫沉淀和质谱分析受体和 G 蛋白，以确定这些特定蛋白质是否受到氧化损伤。总的来说，该项目将评估与正常记忆功能密切相关的三种神经递质系统中与年龄相关的变化，并确定这些回路和突触在衰老过程中发生变化的机制。从这些实验中获得的数据不仅将极大地增强对大脑衰老和认知的理解，而且还能阐明特定神经基质的变化，这些变化对下一代药物治疗的潜在治疗调节感兴趣。此外，为解决这些重点研究工作而提出的实验方法的多样性将为申请人提供出色的博士前培训经验，以支持其既定的职业目标和目的。公共健康相关性：到 2040 年，65 岁以上的人口将占美国人口的 20% 以上，了解老年人记忆力下降的机制是科学和临床上迫切需要关注的问题。该研究项目将测量神经信号传导的突触前和突触后方面，以确定与记忆缺陷相关的衰老海马体中代谢受体和 G 蛋白的具体变化。该项目的研究结果将增强我们对衰老大脑的了解，并为治疗潜力提供新的见解。