Modulation of A-beta production in Alzheimer's disease

阿尔茨海默病（AD）患者表现出广泛的大脑异常。阿尔茨海默病的标志之一是主要由β组成的老年斑的丰富沉积。在一些个体中，家族性早发性AD （FAD）可归因于淀粉样蛋白前体蛋白（APP）基因的特定突变。最近有研究表明，早老素1和2基因（PS1和PS2）的突变会影响β水平。这有力地证明AD可能与APP代谢紊乱有关。相应地，人们对了解调节β产生的基因和因子的分子作用产生了极大的兴趣。朝着这一目标已经取得了很大进展。然而，关于调节β产生的亚细胞机制，特别是神经元（受阿尔茨海默病影响最大的细胞），仍有许多有待阐明。APP的翻译后加工非常复杂，涉及以细胞类型特异性方式发挥作用的途径。该项目的主要目标之一是解剖和分析PS1突变神经元中处理APP和Abeta的亚细胞途径。为了实现这一目标，APP处理将在PS1 M146V突变“敲入”内源性小鼠PS1基因的转基因小鼠的原代神经元中进行检测。这些细胞将被载体（塞姆利基森林病毒和单纯疱疹病毒-1/扩增子）感染，这些载体在APP和PS1中表达野生型和fad相关突变，以及APP转运/分选突变。同样，我们将检测PS1缺陷小鼠的神经元，以进一步评估PS1在APP加工中的作用。有趣的是，雌激素，一种具有许多神经生物学活性的物质，已被证明可以减少β的产生。为了深入了解雌激素抑制Abeta生成的机制，本项目的另一个目标是确定受雌激素作用影响的APP/Abeta加工途径。这些研究将在培养的原代大鼠神经元和人神经元NT2N细胞系中进行。这些研究可能会为特定的亚细胞细胞器和转运途径提供新的见解，这些途径调节神经元APP和β加工。这一信息可能对设计预防或控制阿尔茨海默病病理事件的新策略很重要。

Alzheimer's disease (AD) patients display a wide range of brain abnormalities. One of the hallmarks of AD is the florid deposition of senile plaques composed chiefly of Abeta. In some individuals familial early-onset AD (FAD) is attributable to specific mutations in the Amyloid Precursor Protein (APP) gene. Recently, it has been shown that Abeta levels are affected by mutations in the Presenilin 1 and 2 genes (PS1 and PS2). This argues strongly that AD may involve disturbances in APP metabolism. Correspondingly, there is tremendous interest in understanding the molecular actions of genes and agents that regulated Abeta production. Toward this goal much progress has been made. However, much remains to be elucidated regarding the subcellular mechanisms by which Abeta production is modulated, particularly in neurons (the cells most affected by AD). Post-translational processing of APP is highly complex, involving pathways that function in cell-type specific ways. One of the primary goals of this project is to dissection and analyze the subcellular pathways that process APP and Abeta in neurons harboring mutations in PS1. To accomplish this, APP processing will be examining in primary neurons derived from transgenic mice with PS1 M146V mutation "knocked into" the endogenous murine PS1 gene. These cells will be infected with vectors (Semliki Forest virus and Herpes Simplex Virus-1/amplicons) engineered to express wild-type and FAD-related mutations in APP and PS1, as well as APP trafficking/sorting mutations. Similarly, neurons from PS1-deficient mice will be examined to further assess the role of PS1 in APP processing. Interestingly estrogen, a substance with a number of neurobiological activities, has been shown to reduce Abeta production. To gain insight into the mechanisms by which estrogen opposes the generation of Abeta, another goal of this project is to identify the APP/Abeta processing pathways that are affected by the action of estrogen. These studies will be carried out in cultured primary rat neurons and the human neuronal NT2N cell line. These studies will likely provide new insights into the specific subcellular organelles and trafficking pathways that modulate neuronal APP and Abeta processing. This information may prove important in designing new strategies to prevent or control the pathological events underling Alzheimer's disease.