Synaptic substrates of age-dependent memory deficits

年龄依赖性记忆缺陷的突触基质

• 批准号: 9031276
• 负责人: JOHN F DISTERHOFT
• 金额: $ 281.58万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-15 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9031276
• 关键词: 4-methoxy-7-nitroindolinyl-glutamate; Age; Age-associated memory impairment; Aging; Alzheimer' s Disease; Array tomography; Biological Assay; Biological Preservation; Blinking; Candidate Disease Gene; Cations; Cell Fractionation; Cognition; Cognitive; Cognitive aging; Data; Dendrites; Drug Targeting; Electron Microscopy; Electrons; Epigenetic Process; Epitopes; Fostering; Genes; Glutamates; Goals; HCN1 gene; Heterogeneity; Hippocampus (Brain); Homeostasis; Hybrids; Image; Immunofluorescence Immunologic; Impaired cognition; In Vitro; Individual; Interneurons; Investigation; Ion Channel; Kv4.2 channel; Laser Scanning Microscopy; Lasers; Learning; Link; Location; Maze Learning; Memory; Memory Loss; Memory impairment; Microscopy; Mining; Modeling; Molecular; Neurobiology; Neurons; Output; Pathology; Pattern; Persons; Physiology; Potassium Channel; Progress Reports; Property; Proteomics; Protocols documentation; Rattus; Research; Resolution; Risk Factors; Scanning; Scanning Electron Microscopy; Signal Transduction; Synapses; Synaptic plasticity; Techniques; Testing; Therapeutic; Therapeutic Intervention; Transfection; Vertebral column; Viral; Western Blotting; Work; age effect; age related; aged; aging hippocampus; base; behavior test; behavioral plasticity; combinatorial; conditioning; disease diagnosis; experience; genetic manipulation; hippocampal pyramidal neuron; imaging probe; in vivo; insight; morris water maze; neuron loss; neuronal cell body; normal aging; patch clamp; pathogen; prevent; programs; public health relevance; recombinant viral vector; research study; symptomatology; targeted treatment; therapy design; two-photon; voltage; young adult

 DESCRIPTION (provided by applicant): Though aging itself is the biggest risk factor for Alzheimer's disease (AD), many aged persons with memory problems do not ultimately suffer from AD. In such persons, pathology that would merit AD diagnosis is absent, despite the overlapping cognitive symptomatology. The principal goal of this research program is to model such "normal" age-related cognitive heterogeneity in rats and then use high-resolution techniques to reveal the synaptic and dendritic substrates of age-associated decline in forms of memory that require the hippocampus. As the primary output of the hippocampus, region CA1 has been a primary target of such investigation by us and others. Indeed, past studies have revealed that while major age-related synapse and neuron loss are absent in CA1, more subtle aging-linked changes collude to modify neuronal activity patterns and behavioral plasticity. Importantly, such alterations are present in only a subset of aged rats, with others the same chronological age showing young adult-like acquisition on Morris Water Maze (MWM) learning and trace eyeblink conditioning (TEBC). Such cognitive heterogeneity among aged rats, then, provides an important opportunity to reveal both the substrates of age-related memory decline as well as the substrates of memory preservation. The experiments proposed in this renewal application will continue to reveal the synaptic and dendritic substrates of age-related cognitive heterogeneity, but do so by building on our past findings with conceptual and technical complexity. Specifically, in Aim 1, we will behaviorally characterize young adult and aged F344xBN F1 hybrid rats with MWM learning and TEBC and then probe synaptic Ca2+ signaling with 2-photon laser scanning (2PLSM) Ca2+ imaging and 2-photon glutamate (2Pglutamate) uncaging onto spines in discrete microdomains of individual basal, oblique, and tuft dendrites. Following this high-resolution functional probing, Aims 2 and 3 will use immunogold field emission scanning electron microscopy for backscattered electrons (iFESEM) and immunofluorescence array tomography (iAT) to morphologically reconstruct the imaged dendrites and then proteomically reconstruct the dendrites' signaling networks. Aim 2 will focus on an interactome of ion channels involved in synaptic and dendritic voltage signaling and integration. Aim 3 will probe the imaged dendrites for ion channels involved in an interactome that governs synaptic and dendritic Ca2+ signaling. Using the information provided by these Aims, Aim 4 will rescue age-related memory impairments and signaling abnormalities with viral transfection to up or down-regulate expression of ion channels linked to cognitive impairment or preservation. Such "rescue" will be probed with behavioral testing, 2PLSM Ca2+ imaging, 2Pglutamate uncaging, and reconstructive proteomic microscopy with iFESEM and iAT. Together, the experiments in the proposed Aims will identify the key regulators of dendritic signaling and memory function in aged rats with molecular precision, reveal deep insight into both "successful" and "unsuccessful" cognitive aging, and provide critical information about viable drug targets that could slow or prevent aging-linked cognitive decline.

 描述（由适用提供）：尽管衰老本身是阿尔茨海默氏病（AD）的最大危险因素，但许多患有记忆问题的老年人最终不会遭受AD的困扰。在这样的人中，尽管认知症状重叠，但值得不值得AD诊断的病理。该研究计划的主要目的是建模大鼠中与年龄相关的认知异质性，然后使用高分辨率技术来揭示需要海马的记忆形式下降的突触和树突状底物。作为海马的主要产出，CA1地区一直是我们和其他人的主要投资目标。实际上，过去的研究表明，尽管CA1中没有与年龄相关的主要突触和神经元丧失，但更微妙的衰老变化会协作以改变神经元活动模式和行为可塑性。重要的是，这种改变仅在一部分年龄大鼠的子集中，而其他人则是按年代年龄的年龄，显示了莫里斯水迷宫（MWM）学习和跟踪Eykeblink条件（TEBC）的年轻成人习得。因此，年龄大鼠之间的这种认知异质性为揭示与年龄相关的记忆下降的基材以及记忆保存的底物提供了一个重要的机会。在此续签应用中提出的实验将继续揭示与年龄相关的认知异质性的突触和树突状底物，但要通过构建我们过去具有概念和技术复杂性的发现。 Specifically, in Aim 1, we will behaviorally characterize young adult and aged F344xBN F1 hybrid rats with MWM learning and TEBC and then probe synthetic Ca2+ signaling with 2-photon laser scanning (2PLSM) Ca2+ imaging and 2-photon glutamate (2Pglutamate) uncaging onto spines in discrete microdomains of individual basal, oblique, and tuft树突。在此高分辨率的功能探测之后，AIM 2和3将使用免疫原场发射扫描电子显微镜进行反向散射电子（IFESEM）和免疫荧光阵列层析成像（IAT）来形态学地重建成像的树突，然后将树枝状网络重新构建树枝状网络。 AIM 2将重点放在参与突触和树突电压信号传导和集成的离子通道的相互作用组上。 AIM 3将探测与控制合成和树突状CA2+信号传导相互作用组的离子通道成像的树突。使用这些目标提供的信息，AIM 4将挽救与年龄相关的记忆障碍和信号异常，并具有病毒转化，以向上或下调与认知障碍或保存有关的离子通道的表达。这种“救援”将通过行为测试，2PLSM Ca2+成像，2pglutamate Uncing和IFESEM和IAT进行重建蛋白质组学显微镜进行探测。总之，提出的目标中的实验将确定具有分子精度的老年大鼠树突状信号传导和记忆功能的关键调节因子，揭示了对“成功”和“失败”的认知衰老的深入了解，并提供有关可行药物靶标的关键信息，这些信息可能会减缓或阻止粘液性认知能力下降。