Efficient reversal of Alzheimer's disease fibril formation and elimination of neurotoxicity by a small molecule
Efficient reversal of Alzheimer's disease fibril formation and elimination of neurotoxicity by a small molecule
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DOI：
10.1073/pnas.0405941101
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发表时间：
2004-10-05
影响因子：
11.1
通讯作者：
Ingram, VM
中科院分区：
文献类型：
--
作者：
Blanchard, BJ;Chen, A;Ingram, VM
在阿尔茨海默病(AD)中，从一个大的前体蛋白过度产生的Abeta1-42肽具有正常的氨基酸序列，但当释放时，在中性pH下错误折叠，形成“原纤维”和富含β-折叠的纤维。我们发现，这些原纤维或纤维对某些携带钙离子alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic酸(AMPA)受体的神经细胞是有毒的。破坏Abeta1-42纤维和原纤维的结构可能会导致发现对治疗AD非常有用的分子。通过高通量筛选具有已知“生物活性”的3,000个小分子的文库，可以有效地减少聚集在一起的Abeta1-42的β-折叠含量。我们使用硫代黄素T(THT)作为β-折叠分析来表征先导化合物。在所发现的六种化合物中，最有效的是4，5-二苯基邻苯二甲酰亚胺(DAPH)，在以下条件下：低微摩尔浓度的DAPH废除或极大地减少先前完全形成的Abeta1-42原纤维，而产生不含原纤维的无定形材料，但明显包含一些原纤维和较小的形式。Abeta1-42肽与DAPH共孵育产生无定形物质或空场。DAPH和Abeta1-42共孵育后，用THT荧光法测得的β-折叠含量大大降低，并与THT形成了一种新的荧光络合物。当Abeta1-42肽与DAPH以极低的微摩尔浓度共同孵育时，上述神经毒性(钙内流)被消除。显然，DAPH是AD治疗的一个有前途的候选药物。
The Abeta1-42 peptide that is overproduced in Alzheimer's disease (AD) from a large precursor protein has a normal amino acid sequence but, when liberated, misfolds at neutral pH to form "protofibrils" and fibrils that are rich in beta-sheets. We find that these protofibrils or fibrils are toxic to certain neuronal cells that carry Ca-permeant alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Disrupting the structure of the Abeta1-42 fibrils and protofibrils might lead to the discovery of molecules that would be very useful in the treatment of AD. A high-throughput screen of a library of >3,000 small molecules with known "biological activity" was set up to find compounds that efficiently decrease the beta-sheet content of aggregating Abeta1-42. Lead compounds we're characterized by using thioflavin T (ThT) as a beta-sheet assay. The most effective of six compounds found was 4,5-dianilinophthalimide (DAPH) under-the following conditions: DAPH at low micromolar concentrations abolishes or greatly reduces previously existing fully formed Abeta1-42 fibrils, producing instead amorphous materials without fibrils but apparently containing some protofibrils and smaller forms. Coincubation of the Abeta1-42 peptide with DAPH produces either amorphous materials or empty fields. Coincubation of DAPH and Abeta1-42 greatly reduces the beta-sheet content, as measured with ThT fluorescence, and produces a novel fluorescent complex with ThT. When the Abeta1-42 peptide was coincubated with DAPH at very low micromolar concentrations, the neuronal toxicity mentioned above (Ca2+ influx) was eliminated. Clearly, DAPH is a promising candidate for AD therapy.