The Secretory Chaperone 7B2 as an Endogenous Regulator of Amyloid Pathology

描述（由申请人提供）：阿尔茨海默病（AD）影响520万65岁以上的美国人，预计随着美国人口的普遍老龄化，这一数字将沿着增加。虽然过去十年在定义被认为与认知功能丧失有关的淀粉样蛋白种类的毒性作用方面取得了显着进展，但关于淀粉样蛋白斑块的发病机制仍有许多有待了解。 最近的数据支持这样的观点，即分子伴侣，控制折叠稳态的蛋白质，以多种方式促进适当的神经元功能。我们的实验室最近表明，7 B2，一个小的分泌的神经元蛋白，是与脑淀粉样斑块组织从AD人类和小鼠AD模型。这些数据得到了五项独立生物信息学研究的支持，表明该蛋白质代表了神经退行性疾病的潜在CSF生物标志物。虽然存在于分泌途径，而不是胞质溶胶中，7 B2表现出许多类似于小的热休克蛋白伴侣的生化特性。 与热休克伴侣蛋白家族的成员α晶体蛋白一样，7 B2可以在体外试验中有效地阻断β淀粉样蛋白1-42的纤维化，并且还阻断添加到Neuro 2A细胞培养物中的β淀粉样蛋白的细胞毒性。 目前的R21提案是为了测试大脑7 B2水平可以控制淀粉样斑块沉积的程度并影响已知阿尔茨海默氏症小鼠模型的认知的假设。我们建议将现有的过表达或低表达7 B2的小鼠品系与APP/PS1阿尔茨海默病模型小鼠杂交。 将在6和12月龄时在Morris水迷宫中评估认知能力。 将在每种基因型的6只动物的皮质和海马切片中定量斑块病理学;将同时测量7 B2免疫反应性。将使用化学和离心分离随后ELISA在单独动物的脑中检查淀粉样蛋白寡聚化状态，并且还与基因型相关。总的来说，这些实验构成了对我们假设的直接检验，即7 B2水平与淀粉样斑块和寡聚体形成呈负相关。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) affects 5.2 million Americans over 65, a number expected to increase along with the general aging of the US population. While remarkable progress has been made in the last decade in defining the toxic effects of the amyloid species thought to be involved in loss of cognitive function, much remains to be learned regarding amyloid plaque pathogenesis. Recent data support the idea that chaperones, proteins which control folding homeostasis, contribute to proper neuronal function in a variety of ways. Our laboratory has recently shown that 7B2, a small secreted neuronal protein, is associated with brain amyloid plaques in tissues from both AD humans and from mouse AD models. These data are supported by five independent bioinformatics studies indicating that this protein represents a potential CSF biomarker for neurodegenerative disease. Although present in the secretory pathway and not the cytosol, 7B2 exhibits many biochemical characteristics similar to those of small heat shock protein chaperones. Like alpha crystallin, a member of the heat shock chaperone family, 7B2 can potently block the fibrillation of beta amyloid 1-42 in in vitro tests, and also blocks the cytotoxicity of beta amyloid added to Neuro 2A cell cultures. The current R21 proposal is to test the hypothesis that brain 7B2 levels can control the extent of amyloid plaque deposition and affect cognition in a known mouse model of Alzheimer's. We propose to cross existing mouse strains that either over- or underexpress 7B2 with the APP/PS1 Alzheimer's disease model mouse. Cognitive abilities will be assessed at 6 and 12 months of age in a Morris water maze. Plaque pathology will be quantitated in cortical and hippocampal slices in 6 animals of each genotype; 7B2 immunoreactivity will be measured in concert. Amyloid oligomerization state will be examined in brains of separate animals using chemical and centrifugal separation followed by ELISA and also correlated with genotype. Collectively, these experiments constitute a direct test of our hypothesis that 7B2 levels are negatively correlated with amyloid plaque and oligomer formation.