REGULATION OF INTRANEURONAL AB IN VITRO

阿尔茨海默病(AD)的特征是标志性病变，如 富含淀粉样蛋白的老年斑和神经原纤维缠结。淀粉样β蛋白 (Abeta)多肽，来自一种蛋白水解物 或更多选择性剪接的Abeta前体蛋白(APP) 异构体是神经炎中淀粉样纤维的积木。 阿尔茨海默病患者大脑中积聚的斑块。两大 淀粉样斑块中Abeta的形式终止于氨基酸40或42/43。 这种多肽和脑细胞分泌的Abeta/1-40水平比 Abeta/1-42。然而，Abeta/1-42的可溶性比它聚集的要少得多 比Abeta/1-40容易得多。事实上，Abeta/1-42在 阿尔茨海默病患者大脑中的淀粉样斑块。因此，对 导致Abeta产生的细胞内途径特别是 神经元等脑细胞中的Aβ/1-42会增加我们的 对老年性痴呆发病机制的认识 AD的斑块。在本项目的上一个资金周期中，我们 确认内质网/中间室(ER/IC)为 人类产生Abeta/1-42而不是Abeta/1-40的新位点 NT2N神经元。值得注意的是，一些ER/IC产生的Abeta/1-42形成 一个稳定的、不溶于细胞内的Abeta池， 随着培养的NT2N神经元的老化而积累。这一合计 细胞内Abeta/1-42可能选择性地损害人卵巢癌细胞的存活 脆弱的神经元。因此，在这次续签申请中提出的研究 将测试这样的假设：应用程序处理的扰动会导致 Abeta在细胞内的进行性蓄积，尤其是Abeta/1-42 AD大脑可能导致神经元死亡。为了实现这一点，我们将使用 我们在上一个资金周期中开发的试剂和工具 解剖产生Abeta/1-40和Abeta/1-40的不同细胞内途径 Abeta/1-42。我们将确定Abeta/1-42是否可溶 细胞内Abeta/1-40和Abeta/1-42以及不溶的，聚集的 Abeta/1-40和Abeta/1-42。与其他调查人员密切合作 该计划项目将使我们能够确定如何生产 不同的Abeta池，特别是细胞内的Abeta/1-42是 受监管的。这些研究也应该提供线索，说明 神经元死亡中的细胞内Abeta。

Alzheimer's disease (AD) is characterized by hallmark lesions such as amyloid rich senile plaques and neurofibrillary tangles. Amyloid beta (Abeta) peptides, which are derived from the proteolytic processing of one or more of the alternatively spliced Abeta precursor protein (APP) isoforms are the building blocks of the amyloid fibrils in the neuritic plaques that accumulate in the brains of patients with AD. The 2 major forms of Abeta in amyloid plaques terminate at amino acid 40 or 42/43 of this peptide, and brain cells secrete much high levels of Abeta/1-40 than Abeta/1-42. However, Abeta/1-42 is much less soluble than it aggregates far more readily than Abeta/1-40. Indeed, Abeta/1-42 predominates in the amyloid plaques that riddle the AD brain. Thus, the elucidation of intracellular pathways that lead to the production of Abeta particularly Abeta/1-42 in brain cells such as the neuron would increase our understanding of those mechanisms that underlie the pathogenesis of senile plaques in AD. During the last funding cycle of this Project, we identified the endoplasmic reticulum/intermediate compartment (ER/IC) as a novel site for the production of Abeta/1-42 but not Abeta/1-40 in human NT2N neurons. Significantly, some of the ER/IC produced Abeta/1-42 formed a stable, insoluble pool of intracellular Abeta that progressively accumulated as the NT2N neurons aged in culture. This aggregated intracellular Abeta/1-42 could compromise the survival of selectively vulnerable neurons. Thus, the studies proposed in this renewal application will test the hypothesis that perturbation of APP processing leading to progressive intracellular accumulation of Abeta particularly Abeta/1-42 in AD brains may lead to neuron death. To accomplish this, we will use reagents and tools that we have developed during the last funding cycle to dissect the different intracellular pathways that produce Abeta/1-40 and Abeta/1-42. We will determine whether or not Abeta/1-42, soluble intracellular Abeta/1-40 and Abeta/1-42 as well as insoluble, aggregated Abeta/1-40 and Abeta/1-42. Close collaboration with other investigators in the Program Project will allow us to determine how the production of the different pools of Abeta particularly intracellular Abeta/1-42 are regulated. These studies should also provide clues to the importance of intracellular Abeta in neuron death.