Spherical aggregates of β-amyloid (amylospheroid) show high neurotoxicity and activate tau protein kinase I/glycogen synthase kinase-3β
Spherical aggregates of β-amyloid (amylospheroid) show high neurotoxicity and activate tau protein kinase I/glycogen synthase kinase-3β
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DOI：
10.1073/pnas.1237107100
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发表时间：
2003-05-27
影响因子：
11.1
通讯作者：
Sato, K
中科院分区：
文献类型：
--
作者：
Hoshi, M;Sato, M;Sato, K
β-淀粉样蛋白（Abeta）通过自聚集获得毒性。为了鉴定和表征Abeta聚集体的毒性形式，我们通过使用大量均质的化学合成Abeta（1-40）肽来检查体外聚集条件。我们发现缓慢旋转Abeta（1-40）溶液可重复地产生含有稳定和高毒性部分的自聚集Abeta（1-40）。通过原子力显微镜和透射电子显微镜检查通过甘油梯度离心纯化的聚集体发现，毒性部分是一个完美的球体，我们称之为淀粉样球蛋白（ASPD）。其他Abeta（1-40）聚集体（包括原纤维）无毒。毒性和球体大小之间的相关性研究表明，10- 15-nm ASPD是高毒性的，而当Abeta（1-42）通过缓慢旋转形成ASPD时，10 nm ASPD似乎也存在。然而，Abeta（1-42）-ASPD形成更快，在较低浓度下杀死神经元，并且显示出比Abeta（1-40）-ASPD高约100倍的毒性。在免疫印迹中，毒性ASPD与SDS抗性寡聚体条带相关，而无毒ASPD中不存在这些条带。由于ASPD的形成不受破坏β-折叠相互作用的五肽干扰，Abeta可能通过至少部分不同于原纤维形成的途径形成ASPD。锂的抑制实验表明tau蛋白激酶I/糖原合成酶激酶-3 β参与ASPD诱导的神经变性的早期阶段。在这里，我们描述了ASPD的鉴定和表征，并讨论了其在阿尔茨海默病神经退行性变中的可能作用。
beta-Amyloid (Abeta) acquires toxicity by self-aggregation. To identify and characterize the toxic form(s) of Abeta aggregates, we examined in vitro aggregation conditions by using large quantities of homogenous, chemically synthesized Abeta(1-40) peptide. We found that slow rotation of Abeta(1-40) solution reproducibly gave self-aggregated Abeta(1-40) containing a stable and highly toxic moiety. Examination of the aggregates purified by glycerol-gradient centrifugation by atomic force microscopy and transmission electron microscopy revealed that the toxic moiety is a perfect sphere, which we call amylospheroid (ASPD). Other Abeta(1-40) aggregates, including fibrils, were nontoxic. Correlation studies between toxicity and sphere size indicate that 10- to 15-nm ASPD was highly toxic, whereas ASPD 10 nm also appeared to exist when Abeta(1-42) formed ASPD by slow rotation. However, Abeta(1-42)-ASPD formed more rapidly, killed neurons at lower concentrations, and showed approximate to100-fold-higher toxicity than Abeta(1-40)-ASPD. The toxic ASPD was associated with SDS-resistant oligomeric bands in immunoblotting, which were absent in nontoxic ASPD. Because the formation of ASPD was not disturbed by pentapeptides that break beta-sheet interactions, Abeta may form ASPD through a pathway that is at least partly distinct from that of fibril formation. Inhibition experiments with lithium suggest the involvement of tau protein kinase I/glycogen synthase kinase-3beta in the early stages of ASPD-induced neurodegeneration. Here we describe the identification and characterization of ASPD and discuss its possible role in the neurodegeneration in Alzheimer's disease.