Abstract

Carboxylesterase 2 (CES2) an endoplasmic reticulum (ER) located phaseⅠenzyme plays a vital role in the metabolism of various endogenous and exogenous substances and is regarded as an important target for the design of prodrugs. Unfortunately, superior highly selective probes for ER targeted monitoring of CES2 are not currently available. Herein, we report an ER targeting CES2 selective and sensitive ratiometric fluorescent probe ERNB based on the ER localizing group p-toluenesulfonamide. The ratiometric probe possesses some significant advantages such as high specificity, sensitivity, and high imaging resolution. The probe exhibited excellent subcellular localization when compared with commercial ER tracker, and was used to image CES2 expression in the ER of living cells and tumor tissues. Additionally, using ERNB we evaluated CES2 regulation in DL-dithiothreitol (DTT) and tunicamycin-induced ER stress. Furthermore, we determined the down regulation of CES2 activity and expression in the APAP-induced acute liver injury model. Based on these results we conclude that ERNB is a promising tool for highlighting the role of CES2 in the ER and in exploring the role of CES2 in the development of diseases associated with ER stress.