Comparison of normal aging with Alzheimer's Disease: cellular, synaptic, and vascular indices affecting brain plasticity and neurogenesis

成体海马神经发生(Ahn)和血管生成一起发生在 海马齿状回(DG)，支持啮齿类动物的认知功能和对应激的行为反应。 新生神经元和现有颗粒神经元之间的连接是这些功能的基础。我们发现 正常情况下，衰老(NA)受试者在80岁时有稳定数量的祖细胞(NPC)和 未成熟神经元，但血管生成和神经可塑性随着年龄的增长而减少，并与 这表明，即使在老年人中发生AHN，新生儿的血管支持和连接 神经元可能会减少。此外，我们不知道在老年人中是否有更多的NPC分化为神经胶质细胞，就像 这种情况发生在年老的啮齿动物身上。Ahn在阿尔茨海默病(AD)中较低，如果NPC优先分化 分化成胶质细胞或不分化，有效地分裂、分化和成熟，仍是未知的。我们研究了基因的表达 Kruppel样因子9(KLF9)，一种神经发生依赖性突触可塑性所必需的转录因子，以及 我们发现Klf9的表达随着年龄的增长而下降。我们进一步测试了观察到的年龄相关 血管生成减少可能是由于血管内皮生长因子受体2表达减少所致 (VEGFR2)，它同时调节血管生成和AHN。我们的试点数据显示，内部和外部- 随着年龄的增长，血管细胞表达VEGFR2的细胞减少。血管和树突/棘可塑性改变可能 有助于NA和AD，分离关键的分子调节因子可能导致设计新的AD治疗方法。 在这里，我们建议评估假说产生的分子靶标，在一个平行的项目(1R01AG076949)中， 我们已经提议在相同的140个受试者和大脑区域进行蛋白质组学、单核和空间 多组学(RNA和ATAC)测序，使用数据驱动的方法，可以揭示意想不到的 脑老化和阿尔茨海默病的分子基础。这里提出的方法允许组合可视化 在单细胞水平上选择分子靶点，以及细胞、毛细血管、树突的详细解剖图谱 以及脊椎结构和连接性。我们严谨的方法确保了详细的临床评估，脑组织 质量，统一的组织处理，毒理学和神经病理学的使用，以及严格的纳入/排除标准。 我们将研究来自NIMH、哥伦比亚大学陶布研究所脑库(见字母)的海马体，以及 哥伦比亚大学/NYSPI大脑收藏。我们将评估NA受试者(N=100，年龄14-90岁，57岁)的衰老效应 男性和43名女性)，并将评估60岁及以上的NA受试者与AD的不同之处 年龄和性别匹配的AD受试者(N=40，Braak分期1至4)。目标是量化：(1)神经元和 鼻咽癌的神经胶质分化。(2)树突、棘突和突触及其分子调节因子：2a。高尔基- 染色的树突和棘突；神经丝免疫反应阳性树突；脊椎和突触蛋白 Spinophin、SYN1和PSD95；KLF9基因的表达。(3)血管生成与VEGFR2。(4)相互关系 AIMS 1-3和AD Braak分期、压力暴露、教育水平和性别的细胞和形态数据。

Adult hippocampal neurogenesis (AHN) and angiogenesis occur together in the neurogenic niche of the hippocampus dentate gyrus (DG) and support cognitive functions and behavioral responses to stress in rodents. Connectivity between newborn and existing granule neurons is fundamental for these functions. We found that normally aging (NA) subjects into their eighth decade of life have a stable number of progenitor cells (NPCs) and immature neurons, but angiogenesis and neuroplasticity are decreased with aging and directly correlated with each other, suggesting that, even if AHN occurs in older adults, the vascular support and connectivity of newborn neurons might be reduced. Moreover, we do not know if more NPCs differentiate into glia in older individuals, as it happens in aging rodents. AHN is lower in Alzheimer’s Disease (AD), and if NPCs preferentially differentiate into glia or do not, divide, differentiate and mature efficiently, remains unknown. We investigated expression of Kruppel Like Factor 9 (Klf9), a transcription factor necessary for neurogenesis-dependent synaptic plasticity, and we found an age-associated decline in Klf9 expression. We further tested if the observed age-associated angiogenesis decline could be due to reduced expression of vascular endothelial growth factor receptor 2 (VEGFR2), which regulates both angiogenesis and AHN. Our pilot data show that number of intra- and extra- vascular cells expressing VEGFR2 are fewer with aging. Altered vascular and dendrite/spine plasticity could contribute to NA and AD, and isolating key molecular regulators could lead to designing new treatments for AD. Here we propose to assess hypothesis-generated molecular targets, and in a parallel project (1R01AG076949), we have proposed to perform, in the same 140 subjects and brain region, proteomics, single nucleus and spatial multiomics (RNA and ATAC) sequencing, using data driven approaches which could reveal unanticipated molecular underpinnings of brain aging and AD. The approach proposed here allows combined visualization of selected molecular targets at the single cell level, and detailed anatomical mapping of cell, capillary, dendrite and spine structure and connectivity. Our rigorous methods assure detailed clinical assessment, brain tissue quality, uniform tissue processing, use of toxicology and neuropathology, and strict inclusion/exclusion criteria. We will study hippocampi from NIMH, Columbia University Taub Institute Brain Bank (see letter), and the Columbia/NYSPI brain collection. We will assess aging effects in NA subjects (N=100, age 14-90 years, 57 males and 43 females), and will assess how NA differs from AD comparing NA subjects aged 60 and older with age- and sex-matched AD subjects (N=40, Braak stages 1 through 4). Aims are to quantify: (1) Neuronal and glial differentiation of NPCs. (2) Dendrites, spines and synapses, and their molecular regulators: 2a. Golgi- stained dendrites and spines; 2b. Neurofilament-immunoreactive dendrites; 2c. Spine and synaptic proteins spinophilin, SYN1 and PSD95; 2d. Klf9 mRNA. (3) Angiogenesis and VEGFR2. (4) Relationships between cellular and morphological data from Aims 1-3, and AD Braak stages, stress exposure, education level and sex.