Alzheimer disease (AD) is a neurodegenerative disorder characterized by the aberrant production and accumulation of amyloid-β (Aβ) peptides in the brain. Accumulated Aβ in soluble oligomer and insoluble plaque forms are considered to be a pathological culprit and biomarker of the disorder. Here, we report a fluorescent universal Aβ-indicator YI-13, 5-(4-fluorobenzoyl)-7,8-dihydropyrrolo[1,2-b]isoquinolin-9(6H)-one, which detects Aβ monomers, dimers, and plaques. We synthesized a library of 26 fluorescence chemicals with the indolizine core and screen them through a series of in vitro tests utilizing Aβ as a target and YI-13 was selected as the final imaging candidate. YI-13 was found to stain and visualize insoluble Aβ plaques in the brain tissue, of a transgenic mouse model with five familial AD mutations (5XFAD), by a histochemical approach and to label soluble Aβ oligomers within brain lysates of the mouse model under a fluorescence plate reader. Among oligomers aggregated from monomers and synthetic dimers from chemically conjugated monomers, YI-13 preferred the dimeric Aβ.
阿尔茨海默病(AD)是一种神经退行性疾病,其特征是大脑中淀粉样蛋白-β(Aβ)肽的异常产生和积累。在可溶性寡聚体和不溶性斑块形式中积累的Aβ被认为是该疾病的病理罪魁祸首和生物标志物。在这里,我们报告了一种荧光通用Aβ指示剂YI-13,5-(4-氟苯甲酰)-7,8-二氢吡咯并[1,2-b]异喹啉-9(6H)-酮,它可以检测Aβ单体、二聚体和斑块。我们合成了一个包含吲哚啉核心的26种荧光化学物质库,并通过一系列利用Aβ作为靶点的体外测试对它们进行筛选,YI-13被选为最终的成像候选物。YI-13被发现可以染色和可视化转基因小鼠模型(5XFAD)大脑组织中的不溶性Aβ斑块,通过组织化学方法,并且可以在小鼠模型的大脑裂解物中标记可溶性Aβ寡聚体,通过荧光板阅读器。在从单体聚集的寡聚体和从化学共轭单体合成的二聚体中,YI-13更倾向于二聚体Aβ。