Studies on the inhibitory mechanism of biological molecules and antioxidants for Alzheimer's β-amyloid fibril formation.

本研究在体外构建了β-淀粉样纤维（β-amyloid fibril，fAβ）形成系统，作为阿尔茨海默病（Alzheimer 'sdisease，AD）患者脑内fA β形成的模型。利用这一系统，我们研究了fAβ在体外的形成机制，以及各种生物分子和化合物对fAβ形成的影响。我们还提出了一个成核依赖的聚合模型来解释体外fAβ形成的机制。该模型包括两个阶段，即，成核和延伸阶段。在这项研究中，我们分析了fAβ形成抑制剂。另外，为了了解fAβ在脑内的复杂形成过程，我们研究了在体外Aβ变体混合物中fAβ的形成，以及可能控制fA β形成总速率的细胞核的形成。利用该系统，我们比较了载脂蛋白E和抗氧化剂介导的细胞凋亡机制， ...更多信息 艾德对fAβ形成的抑制作用，发现每种抑制机制不同。其次，我们分析了两种Aβ变异体的相互作用，Aβ42和Aβ1-40（Aβ40）在体外fAβ形成动力学中的作用。Aβ42在Aβ42和Aβ40的混合物中成核，然后通过Aβ40在核的末端和原纤维上的连续缔合进行原纤维延伸。这些结果表明，在不同的共存Aβ物质中，Aβ42在体内fAβ沉积中起着核心作用。第三，我们发现在培养的上皮细胞中，由顶端错误分选的淀粉样前体蛋白产生催化fAβ形成的种子Aβ。种子Aβ的产生依赖于胆固醇的存在，并从可溶性Aβ的构象改变。结论在本研究中，我们开发了一种新的分析方法的fAβ的形成。我们还显示了脑中fAβ形成的几个候选核。我们相信，分析生物或合成的抑制剂与这些核候选物之间的相互作用将为AD的预防和治疗提供重要的治疗靶点。少

IntroductionWe constructed β-amyloid fibril (fAβ) formation system in vitro as a model of that in the brain of patient with Alzheimer's disease (AD). By the use of this system, we have studied the mechanism of fAβ formation in vitro, and estimated the effects of various biological molecules and chemical compounds on fAβ formation. We also proposed a nucleation-dependent polymerization model to explain the mechanisms of fAβformation in vitro. This model consists of two phases, i.e., nucleation and extension phases. In this study, we analyzed the fAβ formation inhibitors. Additionally, in order to understand the complex fAβ formation in the brain, we studied fAβ formation in the mixture of Aβ variants in vitro, and the formation of nucleus, which probably controls total rate of fAβ formation.ResultsFirst, we established a precise analytical system of fAβ formation from Aβ1-42 (Aβ42) in vitro. By the use of the system, we compared the mechanism of apolipoprotein E- and antioxidants-mediat … More ed inhibition of fAβ formation, and found each inhibitory mechanism was different. Secondly, we analyzed the interaction of two kinds of Aβ variant, I.e., Aβ42 and Aβ1-40(Aβ40), in the kinetics of fAβ formation in vitro. Aβ42 nucleate in the mixture of Aβ42 and Aβ40, then the fibril extension proceed by the consecutive association of Aβ40 onto the end of nuclei and existing fibrils. These results suggested the central role of Aβ42 for fAβ deposition in vivo, among the different co-existing Aβ species. Thirdly, we found that a seeding Aβ, which catalyzes the fAβ formation, is generated from the apically missorted amyloid precursor protein in cultured epithelial cell. The seeding Aβ was generated depending on the presence of cholesterol, and conformationally altered from soluble Aβ.ConclusionsIn the present study, we developed a novel analytical methods of fAβ formation. We also showed several candidates of the nuclei for fAβ formation in the brain. We believe that the analysis of the interaction between biological or synthetic inhibitors and these nucleus candidates will provide us with the important therapeutic target for prevention and treatments of AD. Less