PATHOGENIC MECHANISMS OF PRESENILIN MUTATION

描述（申请人摘要）：编码早老素的基因中的突变 1和2（PS-1和PS-2）是家族性早发性 阿尔茨海默病（AD）。操纵早老素表达的研究 将突变形式引入转基因小鼠和培养的细胞中， 证明了PS-1在早期大脑发育中的重要作用， 提出了突变的潜在致病机制，但有技术 限制其实用性。该研究计划将扩大 这些努力通过评估PS-1的正常和致病作用， 成熟和老化的大脑，使用新的小鼠模型和培养的神经元衍生 远离他们我们使用基因靶向技术来建立小鼠实验模型， 忠实地模仿家族性阿尔茨海默病（突变型）的遗传学 “敲入”）或低表达PS-1进入成年期（“低型”）。五条鼠标线 将研究：（1）PS-1和APP野生型;（2）PS-1 P264 L敲入;（3）APP swe 敲入;（4）PS-1/APP双敲入;（5）PS-1亚型。具体目标1将 确定PS-1在小鼠脑成熟和衰老中的功能作用，并测试 FAD连锁的PS-1突变或PS-1功能的部分丧失是否导致 阿尔茨海默型退行性神经病理学比较组织学分析 将评估FAD连锁的PS-1 P264 L突变或PS-1基因敲入的影响 神经元死亡率和大小，拓扑结构和区域的亚型 成熟和衰老小鼠大脑的结构，并将解决细胞 以及PS-1相关神经病理学的生化基础。具体目标2将 检验AD连锁突变型PS-1在正常表达时， 水平，危及脑神经元在体外和体内变性。神经元 对萎缩、细胞凋亡和坏死的脆弱性将被评估为 PS-1基因型对培养的原代神经元的作用 成熟状态和受伤的成年大脑。第3章测试 AD连锁突变体PS-1增加脑中 淀粉样蛋白A β 1 -42肽，通过增强淀粉样蛋白A β 1 -42肽的片段的募集， 淀粉样前体蛋白。A β 1 -42形成的限速步骤 将通过培养的原代细胞的分子和药理学分析来确定 神经元，和预测所作的“招聘假设”将被评估 关键是在培养的神经元和小鼠大脑中。这些研究将进一步 我们对PS-1在大脑中的正常和致病功能的理解， 因此为开发治疗策略提供了重要基础， 减缓阿尔茨海默病的恶化。

DESCRIPTION (Applicant's Abstract): Mutations in the genes encoding presenilins 1 and 2 (PS-1 and PS-2) are a leading cause of familial, early-onset Alzheimer's disease (AD). Studies manipulating presenilin expression and introducing mutant forms into transgenic mice and cultured cells have demonstrated an important role for PS-1 in early brain development and suggested potential pathogenic mechanisms for the mutations, but have technical limitations which constrain their utility. The proposed research will extend these efforts by evaluation of the normal and pathogenic roles of PS-1 in the maturing and aging brain, using novel mouse models and cultured neurons derived from them. We use gene targeting to create mouse experimental models that emulate faithfully the genetics of familial Alzheimer's disease (mutant "knock-in") or underexpress PS-1 into adulthood ("hypomorph"). Five mouse lines will be studied: (1) PS-1 and APP wild type; (2) PS-1P264L knock-in; (3) APPswe knock-in; (4) PS-1/APP double knock-in; (5) PS-1 hypomorph. Specific Aim 1 will define functional roles of PS-1 in mouse brain maturation and aging and test whether an FAD-linked PS-1 mutation or partial loss of PS-1 function cause Alzheimer-type degenerative neuropathology. Comparative histological analyses will evaluate effects of knock-in of the FAD-linked PS-1P264L mutation or PS-1 hypomorphism on neuronal death rates and the size, topology and regional architecture of the maturing and aging mouse brain, and will address cellular and biochemical bases for PS-1-related neuropathologies. Specific Aim 2 will test the hypothesis that an AD-linked mutant PS-1, when expressed at normal levels, endangers brain neurons in vitro and in vivo to degeneration. Neuronal vulnerability to atrophy, apoptosis and necrosis will be evaluated as a function of PS-1 genotype for cultured primary neurons of different maturational states and for the injured adult brain. Specific Aim 3 will test the hypothesis that an AD-linked mutant PS-1 increases production in brain of the amyloid Abeta1-42 peptide by enhancing recruitment of a fragment of the beta-amyloid precursor protein. The rate-limiting step in Abeta1-42 formation will be determined by molecular and pharmacologic analyses of cultured primary neurons, and predictions made by the "recruitment hypothesis" will be evaluated critically in cultured neurons and the mouse brain. These studies will advance our understanding of normal and pathogenic functions of PS-1 in the brain, and so provide an important foundation for developing therapeutic strategies aimed at slowing the progressive deterioration of Alzheimer's disease.