Novel rat Alzheimer's disease models based on AAV-mediated gene transfer to selectively increase hippocampal Aβ levels
Novel rat Alzheimer's disease models based on AAV-mediated gene transfer to selectively increase hippocampal Aβ levels
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DOI：
10.1186/1750-1326-2-11
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发表时间：
2007-01-01
影响因子：
15.1
通讯作者：
Golde, Todd E.
中科院分区：
文献类型：
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作者：
Lawlor, Patricia A.;Bland, Ross J.;Golde, Todd E.
背景：阿尔茨海默病（AD）的特点是认知功能下降和细胞外斑块中淀粉样β肽（Aβ）的积累。淀粉样前体蛋白 (APP) 和早老素的突变改变了 APP 代谢，导致 Aβ42 的积累，Aβ42 是淀粉样蛋白沉积物形成所必需的肽，并被认为启动了导致 AD 的级联反应。然而，Aβ40（细胞分泌的更常见的 Aβ 肽，也是大脑 Aβ 沉积物的主要成分）的作用尚不清楚。在这项研究中，病毒介导的基因转移被用来选择性增加成年 Wistar 大鼠海马中的人 Aβ 42 和 Aβ40 水平，从而检查每种蛋白对 AD 中认知缺陷和病理学的影响。结果：生成了编码 BRI-Aβ cDNA 的腺相关病毒 (AAV) 载体，导致海马高水平表达和分泌特定编码的 Aβ 肽。作为比较，还检查了 AAV 介导的 APPsw 过度表达的影响。输注 AAV 三个月后，对动物进行学习和记忆缺陷的发展测试（开放场地、莫里斯水迷宫、被动回避、新物体识别）。发现了一系列损伤，其中在同时注射 AAV-BRI-A beta 40 和 AAV-BRI-A beta 42 的动物中观察到最明显的缺陷。通过 ELISA 和免疫组织化学分析脑组织，以量化洗涤剂可溶性和不溶性 Aβ 肽的水平。 BRI-A β 42 和 BRI-A β 40+42 过度表达的组合导致去污剂不溶性 A β 水平升高。在表达 APPsw 或 BRI-A beta 40 的大鼠中，未观察到去污剂不溶性 Aβ 的显着增加。除了 AAV-BRI-A beta 42 大鼠显示局灶性、无定形、硫磺素阴性 Aβ 42 沉积物外，在任何大鼠中均未发现任何病理特征。结论：结果表明，AAV 介导的基因转移是模拟 AD 体内病理学方面的有价值的工具，并证明，虽然单独表达 Aβ 42 足以启动 Aβ A beta 40 和 A beta 42 沉积都可能导致认知缺陷。
Background: Alzheimer's disease (AD) is characterized by a decline in cognitive function and accumulation of amyloid-beta peptide (A beta) in extracellular plaques. Mutations in amyloid precursor protein (APP) and presenilins alter APP metabolism resulting in accumulation of A beta 42, a peptide essential for the formation of amyloid deposits and proposed to initiate the cascade leading to AD. However, the role of A beta 40, the more prevalent A beta peptide secreted by cells and a major component of cerebral A beta deposits, is less clear. In this study, virally-mediated gene transfer was used to selectively increase hippocampal levels of human A beta 42 and A beta 40 in adult Wistar rats, allowing examination of the contribution of each to the cognitive deficits and pathology seen in AD.Results: Adeno-associated viral (AAV) vectors encoding BRI-A beta cDNAs were generated resulting in high-level hippocampal expression and secretion of the specific encoded A beta peptide. As a comparison the effect of AAV-mediated overexpression of APPsw was also examined. Animals were tested for development of learning and memory deficits (open field, Morris water maze, passive avoidance, novel object recognition) three months after infusion of AAV. A range of impairments was found, with the most pronounced deficits observed in animals co-injected with both AAV-BRI-A beta 40 and AAV-BRI-A beta 42. Brain tissue was analyzed by ELISA and immunohistochemistry to quantify levels of detergent soluble and insoluble A beta peptides. BRI-A beta 42 and the combination of BRI-A beta 40+42 overexpression resulted in elevated levels of detergent-insoluble A beta. No significant increase in detergent-insoluble A beta was seen in the rats expressing APPsw or BRI-A beta 40. No pathological features were noted in any rats, except the AAV-BRI-A beta 42 rats which showed focal, amorphous, Thioflavin-negative A beta 42 deposits.Conclusion: The results show that AAV-mediated gene transfer is a valuable tool to model aspects of AD pathology in vivo, and demonstrate that whilst expression of A beta 42 alone is sufficient to initiate A beta deposition, both A beta 40 and A beta 42 may contribute to cognitive deficits.