Mehmood Abdul Hadi, Dong Baoli, Lu Yaru, Song Wenhui, Sun Yaru, Lin Weiying
Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Materials Science and Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China.
Anal Methods. 2021 May 21;13(19):2204-2208. doi: 10.1039/d0ay00443j. Epub 2021 Apr 27.
1,4-Dithiothreitol (DTT) is a robust reducing agent that contributes significantly to the folding process of proteins and maintaining endoplasmic reticulum (ER) homeostasis. Abnormally high levels of DTT can lead to severe endoplasmic reticulum stress (ERS), which induces cell death. In addition, DTT can also hinder cell growth and enhance reactive oxygen species (ROS) production in the ER. Herein, an effective turn-on ER-targeting fluorescent probe, ER-DTT, was designed to image DTT for the first time. The probe ER-DTT was based upon naphthalimide as a fluorophore, p-toluenesulfonamide as an exceptional unit for ER-targeting, and sulfoxide as a response site for imaging DTT based on an intramolecular charge transfer (ICT) mechanism. Optical-response experiments showed that the probe ER-DTT had good selectivity and sensitivity for DTT. Furthermore, confocal microscopy indicated that ER-DTT was suitable for selectively targeting ER in living cells and could be implemented to recognize cellular DTT.
1,4-二硫苏糖醇（DTT）是一种强效还原剂，对蛋白质折叠过程和维持内质网（ER）稳态有重要作用。异常高水平的DTT会导致严重的内质网应激（ERS），进而诱导细胞死亡。此外，DTT还会阻碍细胞生长并增强内质网中活性氧（ROS）的产生。在此，首次设计了一种有效的开启型内质网靶向荧光探针ER-DTT用于成像检测DTT。探针ER-DTT以萘二甲酰亚胺作为荧光团，对甲苯磺酰胺作为内质网靶向的特殊单元，亚砜作为基于分子内电荷转移（ICT）机制成像检测DTT的响应位点。光响应实验表明，探针ER-DTT对DTT具有良好的选择性和灵敏度。此外，共聚焦显微镜显示ER-DTT适用于在活细胞中选择性靶向内质网，并可用于识别细胞内的DTT。
