REGULATION OF INTRANEURONAL AB IN VITRO

阿尔茨海默病（AD）的特征在于标志性病变，例如 富含淀粉样蛋白的老年斑和神经纤维缠结。淀粉样蛋白β （Abeta）肽，其来源于一种蛋白质的蛋白水解加工， 选择性剪接的Abeta前体蛋白（APP） 同种型是神经炎性细胞中淀粉样原纤维的结构单元， 这些斑块在AD患者的大脑中积累。的2种主要 淀粉样斑块中的A β形式终止于A β的氨基酸40或42/43， 这种肽，脑细胞分泌高得多的Abeta/1-40水平， Abeta/1-42.然而，Abeta/1-42的可溶性远低于其聚集体 比Abeta/1-40更容易。事实上，Abeta/1-42占主导地位， 淀粉样蛋白斑块在AD大脑中的分布因此， 导致产生Abeta的细胞内途径， 脑细胞中的Abeta/1-42，如神经元， 了解老年性痴呆发病机制的基础， AD中的斑块。在本项目的最后一个融资周期，我们 将内质网/中间室（ER/IC）鉴定为 一种新的人体内产生Abeta/1-42而非Abeta/1-40的位点 NT 2N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，不溶性的细胞内A β池， 随着NT 2N神经元在培养物中老化而积累。该聚合 细胞内Abeta/1-42可以选择性地损害 脆弱的神经元因此，本更新申请中提出的研究 将测试假设，即APP处理的扰动导致 A β，特别是A β/1-42的进行性细胞内积累， AD大脑可能导致神经元死亡。为了实现这一点，我们将使用 我们在上一个融资周期开发的试剂和工具， 剖析产生Abeta/1-40的不同细胞内途径， Abeta/1-42.我们将确定是否Abeta/1-42，可溶性 细胞内A β/1-40和A β/1-42以及不溶性、聚集的 Abeta/1-40和Abeta/1-42。与其他研究人员密切合作， 该计划项目将使我们能够确定如何生产的 不同的Abeta库，特别是细胞内Abeta/1-42， 监管.这些研究还应该提供线索， 在神经元死亡中细胞内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.