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

• 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
• 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' 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

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（尤其是内存）中的下降有关。到2040年，65岁以上的人将占美国人口的20％以上，因此有必要阐明衰老损害记忆并确定改进的治疗干预途径的机制。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在临床上被诊断出记忆力障碍，这表明年代和认知衰老不是同义过程。与阿尔茨海默氏病不同，与年龄相关的记忆变化与广泛的神经元丧失无关。相反，海马内突触的数量有选择性减少，突触后受体的反应性降低。这些行为和神经元后后遗症在老年人中明显，可以成功地在测试的老年大鼠中建模，这些大鼠的记忆是为空间位置记忆的。该项目将利用啮齿动物的衰老模型整合了时间顺序和认知衰老方面，以研究突触前和突触后底物的相关变化。谷氨酸能，胆碱能和GABA能海马电路和受体的平行分析将确定变化是特定于特定的神经递质系统还是更大的大脑的一般变化。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，并使用公正的立体方法进行量化。 M1毒蕈碱和MGLUR5代谢型麸质受体介导的GTP结合（一种受体耦合的功能度量）将使用闪烁接近性计数技术进行选择性测量，该技术特异于其Cognate G蛋白1-subunit，GQ/11。这些变化将与GABAB受体介导的结合的度量对比，而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级联信号信号。在没有明显的受体和G蛋白损失的情况下，已经假设在老年海马中与氧化应激相关的分子过程可能会干扰正常的信号转导。为了检验该假设，将通过免疫沉淀和质谱法分析受体和G蛋白，以确定这些特定蛋白是否氧化损伤。总的来说，该项目将评估与正常内存功能紧密相关的三个神经递质系统中与年龄相关的变化，并确定这些电路和突触在衰老中改变的机制。从这些实验中得出的数据不仅会极大地增强对大脑衰老和认知的理解，而且还可以通过下一代药物治疗来阐明对特定神经底物的变化。此外，为解决这些重点研究工作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标。 公共卫生相关性：由于65岁以上的人将到2040年将占美国人口的20％以上，这是对老年人记忆下降的机制，这是对科学和临床关注的紧迫问题。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老年海马中代谢型受体和G蛋白的特定变化。该项目的发现将增强我们对老年大脑的理解，并为治疗潜力提供新的见解。