Functionalized α-Cyanostilbene Derivatives for Detection of Hypoxia or Proteostasis Imbalance in Live Cells

• Published in: Chemistry : a European journal p. e202402630
• Main Authors: Zhao, Jiamin, Zaheer, Maryam, You, Jiawei, Owyong, Tze Cin, Giel, Marie-Claire, Praveen, Praveen, Li, Wenyi, Hou, Jianquan, Hogan, Conor F, Zhao, Engui, Ding, Siyang, Hong, Yuning
• Format: Journal Article
• Language: English
• Published: Germany 04.09.2024
• Subjects: aggregation-induced emission; cell imaging; proteostasis; Fluorescent probe; unfolded proteins
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.202402630

α-Cyanostilbene represents one of the easily functionalized aggregation-induced emission (AIE) scaffolds. It has been widely adopted for the construction of fluorescent materials for broad applications. Here, we further expanded the utilization of α-cyanostilbene derivatives for the detection of hypoxia or proteostasis imbalance in live cells. Four different amine containing donors were introduced to construct α-cyanostilbene derivatives (R-ASC) with donor-acceptor scaffolds. Equipped with the cysteine (Cys) reactive group, maleimide (MI), R-ASC-MI shows fluorescence turn-on property upon binding with unfolded proteins in vitro and in live cells under proteostatic stress. By virtue of R-ASC-MI, the level of unfolded protein loads in cells can be quantified by flow cytometry, or visualized under microscope. Furthermore, we also characterized the performance of R-ASC-NO2, synthetic precursors of R-ASC-MI, in cellular hypoxia. R-ASC-NO2 revealed upregulated activities of nitroreductase, as well as increased hydrophobicity in live cells, under either chemical (NaN3) induced or atmospheric (1% O2) hypoxia. Together, the advantages of easy modification and high signal-to-noise ratio of new α-cyanostilbene derivatives reported in this work highlight the great potential of α-cyanostilbene in constructing functional biosensors and many other domains.