Clarification of Molecular Mechanism For-AmyloidβGeneration in Alzheimer's Disease

阐明阿尔茨海默病中β-淀粉样蛋白生成的分子机制

• 批准号: 13470035
• 负责人: NISHIMURA Masaki
• 金额: $ 8.19万
• 依托单位: Shiga University of Medical Science
• 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-13470035/
• 关键词: Alzheimer's disease; Amyloidβ; γ-secretase; Presenilin; Nicastrin

Amyloidβ-peptides (Aβ) have been proposed to play a central role in the pathogenesis of Alzheimer disease (AD). The aim of our project is to test the validity of Aβ hypothesis and develop the novel therapeutic strategy for AD. Aβ are generated through the sequential proteolysis of Aβ precursor protein (APP)by β-and γ-secretase. We focus on the biology of γ-secretase, because the pathogenicity of Aβ is dependent on the cleavage site of γ-secretase. (a) Analyses of regulatory mechanism for Aβ generation: Previously we revealed that γ-secretase is a macromolecular complex containing presenilin (PS), and that a novel protein nicastrin (Nct) is an essential constituent of this complex. During this project, we have reported that the PS:Nct complex is indispensable for Notch cleavage as well as APP cleavage (Nat Cell Biol 2001), that the additional constituent PEN-2 is critical for activation of γ-secretase complex (J Neurochem, in press), and that Alcadein is a novel substrate for γ-secretase and involved in Fe65-mediated transcriptional regulation (J Biol Chem, in press). To examine the mechanism for enhancement of pathogenic Aβ (Aβ42/43) generation by clinical PS mutations, we performed a random mutagenesis screen to search for mutant PS 1 which affect the γ-secretase activity. We successfully identified the unique mutants that exclusively generated Aβ42/43 species (in preparation for publication). These mutants are useful to analyze the molecular basis for Aβ42/43 generation and to develop the new strategy for inhibiting Aβ42/43 generation. (b) Test for the validity of Aβ hypothesis: We have been tried to develop transgenic monkeys exhibiting symptom and pathology characteristic to AD. The transgenic monkeys should be useful not only for testing the validity of Aβ hypothesis but also for evaluating the potency and adverse effect of newly developed AD therapies.

淀粉样β肽（Aβ）被认为在阿尔茨海默病（AD）的发病机制中起重要作用。本课题的目的是验证Aβ假说的有效性，为AD的治疗提供新的思路。Aβ是通过β-和γ-分泌酶对Aβ前体蛋白（APP）的连续蛋白水解而产生的。由于Aβ的致病性依赖于γ-分泌酶的切割位点，因此我们重点研究γ-分泌酶的生物学特性。(a)Aβ生成的调控机制分析：我们发现γ-分泌酶是一种含有早老素（PS）的大分子复合物，而一种新的蛋白质nicastrin（Nct）是该复合物的重要组成部分。在该项目期间，我们已经报道了PS：Nct复合物对于Notch切割以及APP切割是必不可少的（Nat Cell Biol 2001），另外的组分PEN-2对于γ-分泌酶复合物的活化是关键的（J Neurochem，出版中），并且Alcadein是γ-分泌酶的新型底物并且参与Fe 65介导的转录调节（J Biol Chem，出版中）。为了研究临床PS突变增强致病性Aβ（Aβ42/43）生成的机制，我们进行了随机诱变筛选以寻找影响γ-分泌酶活性的突变体PS 1。我们成功地鉴定了专门产生Aβ42/43种类的独特突变体（准备发表）。这些突变体有助于分析Aβ42/43产生的分子基础，并为开发抑制Aβ42/43产生的新策略奠定基础。(b)验证Aβ假说的有效性：我们已经尝试开发具有AD症状和病理特征的转基因猴。转基因猴不仅可用于验证Aβ假说的有效性，而且可用于评价新开发的AD治疗药物的效力和不良反应。

项目成果

西村 正樹: "βおよびγセクレターゼを標的としたAlzheimer病の分子治療"医学のあゆみ. 208巻・5号. 443-448 (2004)

Masaki Nishimura：“针对 β 和 γ 分泌酶的阿尔茨海默病的分子治疗”，《医学史》，第 208 卷，第 5 期，443-448（2004 年）。

Rozmahel R, et al.: "Normal brain development in PS1 hypomorphic mice with markedly reduced γ-secretase cleavage of β-APP"Neurobiology and Aging. 23. 187-194 (2002)

Rozmahel R 等人：“PS1 低等态小鼠的正常大脑发育，β-APP 的 γ-分泌酶裂解显着减少”《神经生物学和衰老》23. 187-194 (2002)。

西村 正樹: "Alzheimer病:Aβの生成抑制による治療戦略"最新医学. (印刷中). (2004)

Masaki Nishimura：“阿尔茨海默病：通过抑制 Aβ 产生的治疗策略”最新医学（2004 年）。

Shiraishi H, et al.: "PEN-2 enhances γ-secretase after presenilin heterodimer formation."J Neurochem. in press). (2004)

Shiraishi H 等人：“PEN-2 在早老素异二聚体形成后增强 γ-分泌酶。”J Neurochem，出版中）。

ishimura M: "Therapeutic strategy for Alzheimer disease: inhibition of amyloid βgeneration."Saishin Igaku. (in press).

石村 M：“阿尔茨海默病的治疗策略：抑制 β 淀粉样蛋白的生成。”Saishin Igaku（正在出版）。