Neural Stem Cell Survival and Function in Aging Mice an*

描述(由申请人提供)：脑室下区(SVZ) 哺乳动物大脑的侧脑室和海马体含有 多能神经干细胞(NSCs)群体。这些细胞不断地 异步分裂，产生一个替代干细胞和一个 增殖性祖细胞。在额外的划分和迁移之后， 增殖性祖细胞分化为多个神经谱系。它 一直假设神经干细胞参与神经发生。 并有助于维持大脑的健康 和/或其功能，包括存储器。神经干细胞可能会经历年龄- 可能导致功能障碍或导致病理的相关变化 包括帕金森氏症或阿尔茨海默氏症。这样做的目的是 建议是定义存在的变化、细胞周期参数和 神经干细胞和增殖祖细胞在衰老过程中的功能 以老鼠为模型的大脑。在可能的情况下，这些变化也将 在人体样本中进行评估。目的1：一种双核苷酸类似物标记 方法和DNA复制许可因子的免疫学检测 将利用MCM2来定义具有复制能力的长期标签 保留细胞(假定的干细胞)和增殖性祖细胞 不同日龄小鼠的SVZ。每个种群的细胞周期参数 单元格将从这些数据中定义。这组实验将定义 干细胞和增殖祖细胞浓度和细胞的变化 骑车时间作为年龄的函数，并作为额外的 学习。此外，我们还将测试DNA表达的实用性 以聚合酶亚单位增殖细胞核抗原为代表的研究 用于核苷酸类似物掺入以定义增殖性祖细胞 人口。最后，MCM2和增殖细胞核抗原表达的变化在SVZ和 人脑切片的海马区将被检测，免疫学， 作为年龄的函数。目标2：使用上述方法监控NSC和 增殖祖细胞参数，我们将确定是否改变 这些细胞在衰老过程中的属性是细胞自主的或依赖于 使用神经干细胞移植技术研究脑老化的环境。目标3： 将构建标记MCM2基因的转基因小鼠模型 通过掺入增强型绿色荧光蛋白(EGFP)或 他莫昔芬可诱导Cre-雌激素受体融合。这些型号将允许： 1)确定是否所有静止的神经干细胞都表达MCM2或， 或者，如果存在子群MCM2阴性细胞，并且2)命运 要分别跟踪的NSC种群的数量。能够监控 神经干细胞后代在体内的命运将使我们能够确定年龄- 这些细胞的分化潜能也会发生相关的变化。

DESCRIPTION (provided by applicant): The subventricular zone (SVZ) of the lateral ventricles and the hippocampus of the mammalian brain contain populations of multipotent neural stem cells (NSCs). These cells continually divide, asynchronously, resulting in a replacement stem cell and a proliferative progenitor. Following additional division and migration, proliferative progenitors differentiate towards multiple neural lineages. It has been hypothesized that NSCs participate in neurogenesis throughout the life of the organism and contribute to maintaining the health of the brain and/or its functions, including memory. It is possible that NSCs undergo age- related changes that may lead to dysfunction or contribute to pathologies including Parkinson's or Alzheimer's diseases. The objectives of this proposal are to define changes in the presence, cell cycle parameters and function of the NSC and proliferative progenitor populations during aging in the brain using the mouse as a model. Where possible, such changes will also be assessed in human samples. Aim 1: A double nucleotide analog labeling method, and immunological detection of the DNA replication licensing factor MCM2 will be utilized to define replication competent long-term label retaining cells (putative stem cells) and proliferative progenitors within the SVZ of mice of different ages. Cell cycle parameters for each population of cells will be defined from these data. This set of experiments will define changes in the stem cell and proliferative progenitor concentrations and cell cycling times as a function of age and serve as a baseline for additional studies. Additionally, we will test the utility of expression of the DNA polymerase subunit proliferating cell nuclear antigen (PCNA) as a surrogate for nucleotide analog incorporation in defining the proliferative progenitor population. Finally, changes in MCM2 and PCNA expression in the SVZ and hippocampal regions of human brain sections will be assayed, immunologically, as a function of age. Aim 2: Using methods described above to monitor NSC and proliferative progenitor parameters, we will determine if changes in the properties of these cells during aging are cell autonomous or dependent on the environment of the aging brain using NSC transplantation techniques. Aim 3: Transgenic mouse models will be constructed in which the MCM2 gene is marked by incorporation of either enhanced green fluorescent protein (EGFP) or a tamoxifin inducible Cre-estrogen receptor fusion. These models will allow: 1) determination of whether all quiescent neural stem cells express MCM2 or, alternatively, if a sub-population MCM2 negative cells exists and 2) the fate of NSC populations to be followed, respectively. The ability to monitor the fates of neural stem cell progeny in vivo will allow us to determine if age- related changes in the differentiation potentials of these cells occur.