EXPRESSION PROLIFING OF ENDOSOMAL PATHWAYS IN AD

阿尔茨海默病(AD)和唐氏综合征(DS)的溶酶体系统和神经营养支持缺陷伴随着内吞相关基因的表达改变。App在DS细胞中的三次复制可引起类似的由B、C-末端APP片段(LiCTF)介导的内吞途径功能障碍，而不依赖于A&。这种内体表型与逆行神经营养支持失败和 基底前脑胆碱能神经元变性。我们建议在由APP/APP代谢物和内体信号效应器组成的相互关联的通路中识别特定的基因及其蛋白，该通路影响AD病理相关过程，包括易损隔海马神经元的内体-溶酶体运输、自噬、神经营养信号和细胞周期折返缺陷。 我们将在相关动物模型和人脑中靶向将异常的内体表型与脆弱的BFCNs和CA1神经元的神经变性联系起来的基因和蛋白质，包括App依赖和App非依赖途径。在目标1中，我们将确定与APP/BCTF和神经营养因子信号通路相关的离散表达变化，在三体小鼠和野生型小鼠海马伞-穹隆切断后的BFCNs中，外源性NGF救援前后。在目标2中，我们将确定一个异常信号通路中的关键角色，该信号通路导致隔海马环路内脆弱神经元与较不脆弱神经元从内体表型异常到神经变性。在目标3中，我们假设APP在FAD和DS中的过度表达是通过BCTF介导的，并涉及Rab5驱动的神经退行性变途径。利用一个新的Rab5小鼠模型，我们将确定Rab5上调是否是导致内体功能障碍和神经变性的必要和充分的因素，或者是否也需要APP/ISCTF信号转导。通过对小鼠APP、BCTF和Rab5水平的遗传操作，结合LCM获得的脆弱细胞中的qPCR和细胞死亡标记的免疫细胞化学，可以预测与相互关联的APP/BCTF和Rab5激活的信号级联相关的基因变化，从而在这些启动神经变性的关键途径中识别新的潜在治疗靶点。

Lysosomal system and neurotrophic support defects In Alzheimer's disease (AD), and Down's syndrome (DS) are accompanied by altered expression of endocytosis-related genes. Triplication of App in DS cells causes similar endocytic pathway dysfunction mediated by the B C-terminal APP fragment (liCTF), independent of A&. This endosomal phenotype is associated with retrograde neurotrophic support failure and degeneration of basal forebrain cholinergic neurons (BFCNs). We propose to identify specific genes and their proteins In an interrelated pathway that consists of APP/APP metabolites and endosomal signaling effectors that impinge upon AD pathology-related processes including endosomal-lysosomal trafficking, autophagy, neurotrophic signaling, and cell cycle reentry defects in vulnerable septohippocampal neurons. We will target genes and proteins that link the abnormal endosomal phenotype to neurodegeneration In vulnerable BFCNs and CAI neurons in relevant animal models and human brains, including both App-dependent and App-independent pathways. In Aim 1 we will identify discrete expression changes related to APP/BCTF and neurotrophin signaling pathways in BFCNs In trisomic mice and following fimbria-fornix (FF) transections in wild type mice before and after exogenous NGF rescue. In Aim 2 we will define key players in an aberrant signaling pathway leading from abnormal endosomal phenotype to neurodegeneration in vulnerable versus less vulnerable neurons within the septohippocampal circuit. In Aim 3, we hypothesize that APP overexpression in FAD and DS is mediated through BCTF and involves a rab5-driven pathway to neurodegeneration. Using a novel rab5 mouse model, we will determine whether rab5 up regulation is necessary and sufficient to cause endosomal dysfunction and neurodegeneration, or whether APP/ISCTF signaling is also required. Genetic manipulations of APP, BCTF, and rab5 levels In mice, coupled with qPCR in vulnerable cells acquired by LCM and immunocytochemistry for cell death markers are predicted to identify gene changes associated with interrelated APP/BCTF- and rab5-inifiated signaling cascades, thus identifying new potential therapeutic targets within these key pathways that initiate neurodegeneration.