College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Normal University, Jinan 250014, P. R. China.
Anal Chem. 2021 Nov 16;93(45):15088-15095. doi: 10.1021/acs.analchem.1c03334. Epub 2021 Nov 3.
Alzheimer's disease (AD) involves multiple pathological factors that mutually cooperate and closely contact to form interaction networks for jointly promoting the AD progression. Therefore, the comonitoring of different factors is particularly valuable for elucidating their level dynamics and complex interactions. However, such significant investigations remain a major challenge due to the lack of unimolecular fluorescent probes capable of simultaneous and discriminative visualization of multiple targets. To address this concern, as proof of principle, we rationally designed a unimolecular fluorescent probe to discriminate and simultaneously profile amyloid-β (Aβ) plaques and peroxynitrite (ONOO), which are both the pronounced AD pathological factors. Herein, a novel ONOO reaction trigger was installed onto an Aβ plaque binding fluorophore to generate a dual functional fluorescent probe, displaying completely separate spectral responses to Aβ plaques and ONOO with high selectivity and sensitivity. With this probe, for the first time, we comonitored the distribution and variation of Aβ plaques and ONOO through two independent fluorescence channels, demonstrating their close apposition and tight correlation during AD course in live cell and mouse models through two-photon imaging mode. Notably, Aβ aggregates induce the neuronal ONOO generation, which conversely facilitates Aβ aggregation. The two critical events, ONOO stress and Aβ aggregation, mutually amplify each other through positive feedback mechanisms and jointly promote the AD onset and progression. Furthermore, by coimaging of the level dynamics of Aβ plaques and ONOO, we found that the cerebral ONOO is a potential biomarker, which emerges earlier than Aβ plaques in transgenic mouse models. Overall, the dual-channel responsive performance renders this probe as a powerful imaging tool to decipher Aβ plaque-ONOO interactions, which will facilitate AD-associated molecular pathogenesis elucidation and multitarget drug discovery.
阿尔茨海默病（AD）涉及多种病理因素，它们相互合作并紧密联系，形成相互作用网络，共同促进 AD 的进展。因此，共同监测不同的因素对于阐明它们的水平动态和复杂相互作用特别有价值。然而，由于缺乏能够同时和区分地可视化多个靶标的单分子荧光探针，因此进行这样的重要研究仍然是一个主要挑战。为了解决这个问题，作为原理证明，我们合理设计了一种单分子荧光探针，以区分和同时描绘淀粉样β（Aβ）斑块和过氧亚硝酸盐（ONOO），这两者都是明显的 AD 病理因素。在此，将一种新的 ONOO 反应触发安装到 Aβ斑块结合荧光团上，生成具有高选择性和灵敏度的双功能荧光探针，该探针对 Aβ斑块和 ONOO 具有完全分离的光谱响应。使用该探针，我们首次通过两个独立的荧光通道共同监测 Aβ斑块和 ONOO 的分布和变化，通过双光子成像模式在活细胞和小鼠模型中证明了它们在 AD 过程中的紧密接近和紧密相关性。值得注意的是，Aβ聚集体诱导神经元 ONOO 的产生，而反过来又促进 Aβ的聚集。这两个关键事件，ONOO 应激和 Aβ聚集，通过正反馈机制相互放大，共同促进 AD 的发生和进展。此外，通过 Aβ斑块和 ONOO 的水平动态的共成像，我们发现大脑中的 ONOO 是一种潜在的生物标志物，它在转基因小鼠模型中比 Aβ斑块更早出现。总体而言，双通道响应性能使该探针成为破译 Aβ斑块-ONOO 相互作用的有力成像工具，这将有助于阐明 AD 相关的分子发病机制和多靶标药物发现。
