Elucidation of aggregation mechanism of Alzheimer's β-peptides and development of their aggregation inhibitors

阿尔茨海默病β肽聚集机制的阐明及其聚集抑制剂的开发

基本信息

批准号：
13460048
负责人：
IRIE Kazuhiro
金额：
$ 9.66万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13460048/
关键词：
Alzheimer's disease Aβ42 amyloid β-sheet turn familial Alzheimer's disease βアミロイド凝集 β-sheet β-turn 家族性アルツハイマー病 Aβ1-42

项目摘要

Alzheimer's disease is neuropathologically characterized by the progressive deposition of amyloid in the braid parenchyma and cortical blood vessels. This deposition mainly consists of 40-and 42-mer β-amyloid peptides (Aβ40, Aβ42) which show neurotoxicity and aggregative ability. Cerebral amyloid angiopathy (CAA) in familial Alzheimer's disease is related to missense mutations inside the coding region of these Aβpeptides. In order to clarify the aggregation mechanism of Aβpeptides, all of the variants of Aβ40 and Aβ42 found in CAA were synthesized in a highly pure form and examined for neurotoxicity in PC12 cells and aggregative ability.All of the Aβ40 mutants at positions 22 and 23 showed stronger neurotoxicity than wild-type Aβ40. Similar tendency was observed for Aβ42 mutants at positions 22 and 23 whose neurotoxicity was 50〜200 times stronger than that of the corresponding Aβ40 mutants, indicating that these Aβ42 mutants are mainly involved in the pathogenesis of CAA. Especially, E … More 22Q-Aβ42 (Dutch) and E22K-Aβ42 (Italian) aggregated extensively, supporting the clinical evidence that Dutch and Italian patients are diagnosed as hereditary cerebral hemorrhage with amyloidosis. In contrast, A21 G (Flemish) mutation needs alternative explanation with the exception of physicochemical properties of Aβmutants. The FI-IR spectra suggested that aggregation increases theβ-sheet contents of the Aβpeptides. However, turn was also a critical secondary structure for aggregation since residues at positions 22 and 23 that preferably form two-residue β-turn significantly enhanced the aggregative ability.To identify amino acid residues that are important for the β-sheet formation, a series of proline-substituted mutants of Aβ42 was synthesized and their aggregative ability and neurotoxicity were investigated. Only E22P-Aβ42 extensively aggregated with stronger neurotoxicity than wild-type Aβ42, suggesting that the residues at positions 15〜21 and 24〜32 are involved in the intermolecular β-sheet formation, and that turn formation at positions 22 and 23 plays a crucial role in the aggregation and neurotoxicity of Aβpeptides. These findings become a basis for designing new aggregation inhibitors of Aβpeptides. Less

阿尔茨海默病的神经病理学特征是淀粉样蛋白在辫状实质和皮质血管中进行性沉积，这种沉积主要由 40 聚体和 42 聚体 β-淀粉样肽（Aβ40、Aβ42）组成，具有神经毒性和聚集能力。家族性阿尔茨海默病 (CAA) 与这些 Aβ 肽编码区域内的错义突变有关。为了阐明Aβ肽的聚集机制，CAA中发现的Aβ40和Aβ42的所有变体都以高纯度的形式合成，并检查了PC12细胞中的神经毒性和聚集能力。所有位于22和23位的Aβ40突变体都表现出比Aβ40更强的神经毒性。野生型 Aβ40 的 22 和 23 位 Aβ42 突变体也观察到类似的趋势，其神经毒性为比相应的 Aβ40 突变体强 50-200 倍，表明这些 Aβ42 突变体主要参与 CAA 的发病机制，特别是 E … More 22Q-Aβ42（荷兰语）和 E22K-Aβ42（意大利语）普遍聚集，支持了 CAA 的发病机制。临床证据表明，荷兰和意大利患者被诊断为遗传性脑出血伴淀粉样变性，相反，需要A21 G（Flemish）突变。除了 Aβ 突变体的理化性质外，FI-IR 光谱表明聚集增加了 Aβ 肽的 β-折叠含量。然而，转角也是聚集的关键二级结构，因为 22 和 23 位的残基优选形成两个。 -残基β-转角显着增强了聚集能力。为了鉴定对β-折叠形成重要的氨基酸残基，一系列脯氨酸取代的突变体合成了Aβ42并研究了它们的聚集能力和神经毒性，只有E22P-Aβ42聚集比野生型Aβ42具有更强的神经毒性，表明15〜21和24〜32位的残基广泛参与分子间β-折叠的形成。并且第 22 和 23 位的转角形成在 Aβ 肽的聚集和神经毒性中起着至关重要的作用。为设计新型 Aβ 肽聚集抑制剂奠定了基础。