Critical role of interfaces and agitation on the nucleation of Aβ amyloid fibrils at low concentrations of Aβ monomers
Critical role of interfaces and agitation on the nucleation of Aβ amyloid fibrils at low concentrations of Aβ monomers
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DOI：
10.1016/j.bbapap.2010.01.012
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发表时间：
2010-04-01
影响因子：
3.2
通讯作者：
Naiki, Hironobu
中科院分区：
文献类型：
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作者：
Morinaga, Akiyoshi;Hasegawa, Kazuhiro;Naiki, Hironobu
淀粉样蛋白沉积是包括阿尔茨海默病（AD）在内的各种神经退行性疾病的病理学标志，其中淀粉样蛋白β-肽（A β）通过成核依赖性聚合机制聚合成淀粉样蛋白原纤维。生物膜或其他界面以及脑中细胞外液的对流可影响体内A β淀粉样蛋白原纤维的形成。在这里，我们研究了聚合动力学的2.5，5，10和20 μ M的A β在存在或不存在的空气-水界面（AWI）使用荧光光谱和荧光显微镜与淀粉样蛋白特异性染料，硫磺素T。当溶液与AWI一起孵育并处于静止状态时，在所有检测的A β浓度下均观察到淀粉样蛋白原纤维形成。相比之下，当没有AWI孵育时，仅在较高的A β浓度（10和20 μ M）下观察到淀粉样蛋白原纤维形成。重要的是，当5 μ M A β溶液与AWI一起孵育时，首先在AWI处观察到ThT反应性膜，而在本体中没有任何其他ThT反应性聚集体。当5 μ M的A β溶液与AWI一起旋转时，淀粉样蛋白原纤维的形成大大加速，其中在AWI下首先观察到ThT反应性膜，然后在整个混合物中观察到ThT反应性聚集体。当5 μ M A β溶液含有聚丙烯光盘旋转无AWI，淀粉样蛋白原纤维的形成也大大加快，其中细ThT反应性聚集体首先被发现附着在边缘的光盘。这些结果表明，淀粉样纤维形成的接口和搅拌的关键作用。此外，消除AWI可能是必要的，以正确评估各种生物分子在体外淀粉样蛋白形成研究中的作用。(C)2010 Elsevier B. V.保留所有权利。
Amyloid deposits are pathological hallmarks of various neurodegenerative diseases including Alzheimer's disease (AD), where amyloid beta-peptide (A beta) polymerizes into amyloid fibrils by a nucleation-dependent polymerization mechanism. The biological membranes or other interfaces as well as the convection of the extracellular fluids in the brain may influence A beta amyloid fibril formation in vivo. Here, we examined the polymerization kinetics of 2.5, 5, 10 and 20 mu M A beta in the presence or absence of air-water interface (AWI) using fluorescence spectroscopy and fluorescence microscopy with the amyloid specific dye, thioflavin T. When the solutions were incubated with AWI and in quiescence, amyloid fibril formation was observed at all A beta concentrations examined. In contrast, when incubated without AWI, amyloid fibril formation was observed only at higher A beta concentrations (10 and 20 mu M). Importantly, when the 5 mu M A beta solution was incubated with AWI, a ThT-reactive film was first observed at AWI without any other ThT-reactive aggregates in the bulk. When 5 mu M A beta solutions, were voltexed or rotated with AWI, amyloid fibril formation was considerably accelerated, where a ThT-reactive film was first observed at AWI before ThT-reactive aggregates were observed throughout the mixture. When 5 mu M A beta solutions containing a polypropylene disc were rotated without AWI, amyloid fibril formation was also considerably accelerated, where fine ThT-reactive aggregates were first found attached at the edge of the disc. These results indicate the critical roles of interfaces and agitation for amyloid fibril formation. Furthermore, elimination of AWI may be essential for proper evaluation of the roles of various biological molecules in the amyloid formation studies in vitro. (C) 2010 Elsevier B.V. All rights reserved.