Near-Infrared Fluorescence Probe for Evaluating Acetylcholinesterase Activity in PC12 Cells and In Situ Tracing AChE Distribution in Zebrafish

Abstract

Acetylcholinesterase (AChE) plays crucial roles in numerous physiological processes such as cell differentiation, cell apoptosis, and nerve tissue developments. Hence, it is highly necessary to design a fluorescent probe for monitoring AChE activity in complex living organisms. In this work, a near-infrared (NIR) off-on probe (<b>CyN</b>) was developed for AChE detection. <b>CyN</b> was exactly synthesized by introducing an <i>N</i>,<i>N</i>-dimethyl carbamyl moiety to hemicyanine (<b>CyOH</b>). AChE can "light up" strong NIR fluorescence through a cleavage special ester bond and transform <b>CyN</b> into <b>CyOH</b>. Moreover, <b>CyN</b> was qualified for imaging the dynamic change of AChE activity in PC12 cells with retinoic acid or hypoxia stimulation. In particular, the probe has been successfully applied for in situ tracing the intact distribution of AChE in living zebrafish. The observations indicate that major occurrence sites of endogenic AChE on zebrafish are the yolk sac and neuromasts. Overall, <b>CyN</b> shows great potential for use in AChE-related physiological studies.