Substrates of selective neuronal vulnerability in aging: neocortical pyramidal neurons and their surrounding neuropil environment in visual versus frontal cortex of young and aged rhesus monkeys

衰老过程中选择性神经元脆弱性的基础：年轻和老年恒河猴视觉与额叶皮层中的新皮质锥体神经元及其周围神经元环境

• 批准号: 10194943
• 负责人: JENNIFER I LUEBKE
• 金额: $ 32.18万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10194943
• 关键词: Action Potentials; Age-associated memory impairment; Aging; Anatomy; Area; Astrocytes; Behavioral; Brain; Cell physiology; Cells; Cognitive; Data; Databases; Dendritic Spines; Dependence; Dyes; Electrophysiology (science); Environment; Funding; Future; Goals; Immunofluorescence Immunologic; Immunohistochemistry; Impaired cognition; In Situ; In Vitro; Individual; Inflammation; Inflammatory; Laser Scanning Confocal Microscopy; Macaca mulatta; Maps; Mediating; Membrane; Microglia; Monkeys; Morphology; Myelin; Neuroglia; Neurons; Neuropil; Oligodendroglia; Outcome; Oxidative Stress; Paraffin; Pathway interactions; Pattern; Performance; Physical shape; Physiological; Population; Predisposition; Prefrontal Cortex; Primates; Process; Property; Proteins; Resolution; Sensory; Series; Short-Term Memory; Slice; Specific qualifier value; Structure; Synapses; Testing; Therapeutic; Tissue Sample; United States National Institutes of Health; Vertebral column; Visual; Work; age effect; age group; age related; aged; aging population; animal tissue; area striata; biocytin; brain dysfunction; cell type; cognitive function; cognitive performance; cytokine; density; design; frontal lobe; hippocampal pyramidal neuron; interest; middle age; molecular phenotype; neocortical; neuron loss; normal aging; novel; patch clamp; postsynaptic; white matter

Normal aging in primates often leads to impaired cognitive function, particularly in working memory, which begins to decline in middle-age. Our group and others have established that age-related cognitive impairment is not due to overt death of neurons but rather is associated with a constellation of sublethal changes to neurons particularly in layer (L3), such as spine, synapse and myelin loss and consequent alterations to synaptic and intrinsic electrophysiological properties. Importantly these structural and functional changes have been abundantly observed with aging in neurons and white matter pathways in the prefrontal cortex (PFC), a brain area that is a key player in working memory. By contrast, the properties of primary visual cortex (V1) pyramidal neurons are largely spared during normal aging. We currently lack a mechanistic understanding of why pyramidal neurons in these two brain areas are differentially vulnerable in normal aging or how age- related changes at the single-cell and pathway level in PFC impact network function and thus working memory performance. The overall hypothesis of this project is that selective vulnerability of neurons and associated networks in LPFC compared to V1 during aging is due to key differences in both the intrinsic properties and the neuropil context of neurons in the two areas, and a greater susceptibility of neurons in LPFC to increases in oxidative stress and inflammation. We propose a novel experimental approach -multiplexed immunohistochemistry combined with high resolution structural analyses of physiologically characterized individual neurons- to compare the properties of individual LPFC and V1 pyramidal neurons in the context of their surrounding neuropil in young and aged rhesus monkeys. These monkeys will also have been assessed for cognitive status, pathway integrity, and CSF pro-inflammatory cytokine levels as part of other existing NIH- funded projects. This project has two aims: 1) To assess the morphological properties of physiologically characterized L3 pyramidal neurons in LPFC and V1 of young and aged monkeys. We will assess dendritic topology and the number and density of dendritic spine subtypes and correlate these data with existing data on 30 different physiological properties of these same cells. 2) To characterize the normative properties and effects of aging on the same L3 pyramidal neurons studied in Aim 1 in the context of the neuropil. We will perform in situ immunofluorescence multiplexing of ~20 protein targets on the same tissue sample to determine the molecular phenotype of biocytin-filled layer 3 pyramidal neurons. A major outcome of this project will be the ability to quantitatively specify those parameters that differ between L3 pyramidal neurons in two highly distinct brain areas and which combination of parameters best predict cognitive impairment in aging. This study will form the basis of future series of larger studies to investigate relationships and co-dependence of age-related cellular changes in a variety of cell types, laminae and cortical areas during normal aging that can be correlated with cognitive performance in rhesus monkeys.

灵长类动物的正常衰老通常会导致认知功能受损，尤其是工作记忆受损， 中年时开始衰退。我们的小组和其他人已经确定，与年龄相关的认知障碍 并不是由于神经元的明显死亡，而是与一系列亚致死性变化有关 神经元，特别是层 (L3) 中的神经元，例如脊柱、突触和髓鞘质损失以及随之而来的改变 突触和内在的电生理特性。重要的是，这些结构和功能的变化 大量观察到前额皮质（PFC）神经元和白质通路的老化 大脑区域是工作记忆的关键区域。相比之下，初级视觉皮层 (V1) 的特性 在正常衰老过程中，锥体神经元基本上没有受到影响。我们目前缺乏对机制的理解 为什么这两个大脑区域的锥体神经元在正常衰老过程中存在不同的脆弱性，或者年龄如何- PFC 中单细胞和通路水平的相关变化影响网络功能，从而影响工作记忆 表现。该项目的总体假设是神经元和相关的选择性脆弱性 LPFC 中的网络与老化过程中的 V1 相比，是由于内在特性和 两个区域中神经元的神经元环境，以及 LPFC 中的神经元对增加的敏感性更大 氧化应激和炎症。我们提出了一种新颖的实验方法——多重实验 免疫组织化学结合生理特征的高分辨率结构分析 单个神经元 - 比较单个 LPFC 和 V1 锥体神经元在以下情况下的特性 年轻和年老恒河猴周围的神经纤维。这些猴子也将接受评估 作为其他现有 NIH- 的一部分，用于认知状态、通路完整性和 CSF 促炎细胞因子水平 资助的项目。该项目有两个目标：1）评估生理学的形态特性 表征了年轻和年老猴子的 LPFC 和 V1 中的 L3 锥体神经元。我们将评估树突状 拓扑结构以及树突棘亚型的数量和密度，并将这些数据与现有数据相关联 这些相同细胞有 30 种不同的生理特性。 2) 描述规范属性和 衰老对目标 1 中研究的相同 L3 锥体神经元在神经纤维网背景下的影响。我们将 对同一组织样本上约 20 个蛋白质靶标进行原位免疫荧光多重检测 确定充满生物胞素的第 3 层锥体神经元的分子表型。该项目的一个主要成果 将能够定量指定两个 L3 锥体神经元之间不同的参数 高度不同的大脑区域以及哪些参数组合最能预测衰老过程中的认知障碍。 这项研究将构成未来一系列更大规模研究的基础，以调查关系和相互依赖 正常衰老过程中各种细胞类型、细胞层和皮质区域与年龄相关的细胞变化 可以与恒河猴的认知表现相关。