REGULATION OF ALZHEIMER AMYLOID GENERATION BY NEURONS

β -淀粉样蛋白（Abeta）在易损脑区沉积是阿尔茨海默病（AD）的一个不变特征。β是由淀粉样蛋白前体蛋白（betaAPP）的调控裂解形成的。betaAPP的代谢主要通过转染人betaAPP的克隆细胞系的研究来阐明。然而，由于神经元是阿尔茨海默病中最丰富的Abeta来源，也是受影响最大的细胞类型，因此研究神经元中betaAPP代谢和Abeta生成对于阐明阿尔茨海默病患者大脑中发生的生物学过程将具有重要意义。我们的目的是研究β和β - app在啮齿动物原代神经元培养中的内源性加工和细胞内运输。此外，我们正在研究在细胞系中观察到的betaAPP加工途径的相对利用是否在神经元培养中以类似的方式受到调节。已知的betaAPP代谢调节因子，如蛋白磷酸化和第一信使神经递质信号转导系统，以及性腺激素治疗正在这些皮质培养中进行评估。利用放射性测序和代谢标记-质谱分析，我们最近发现变异AbetaGlu11肽是神经元分泌的主要Abeta物种。此外，我们发现用17 -雌二醇或蛋白磷酸酶抑制剂治疗神经元在减少淀粉样蛋白生成的β肽分泌方面特别有效。阐明控制神经元中β - app和β代谢的分子和细胞过程将为寻求合理的阿尔茨海默病治疗策略提供重要信息。

Deposition of beta-amyloid (Abeta) in vulnerable brain regions is an invariable feature of Alzheimer's disease (AD). Abeta is formed by the regulated cleavage of the amyloid precursor protein (betaAPP). The metabolism of betaAPP has been elucidated mainly by studies in clonal cell lines transfected with human betaAPP. However, since neurons are the most abundant source of Abeta and are the most affected cell-type in AD, the study of betaAPP metabolism and Abeta generation in neurons will be important to elucidate the biological processes occuring in the brain of those afflicted by AD. Our objective is to study the endogenous processing and intracellular trafficking of Abeta and betaAPP in rodent primary neuronal cultures. Furthermore, we are investigating whether the relative utilization of processing pathways for betaAPP are regulated in a similar manner in neuronal cultures as has been observed in cell lines. Known regulators of betaAPP metabolism, such as protein phosphorylation and first messenger neurotransmitter signal transduction systems, and gonadal hormone treatment are being assessed in these cortical cultures. Using radiosequencing and metabolic labeling- mass spectrometry, we have recently discovered that variant AbetaGlu11 peptides are principal Abeta species secreted by neurons. Moreover, we have found that treatment of neurons with 17beta-estradiol or protein phosphatase inhibitors are especially effective at reducing secretion of amyloidogenic Abeta peptides. The elucidation of the molecular and cellular processes governing the metabolism of betaAPP and Abeta in neurons will provide important information in the pursuit of rational therapeutic strategies for AD.