Discovery of Butyrylcholinesterase-Activated Near-Infrared Fluorogenic Probe for Live-Cell and In Vivo Imaging

Abstract

Butyrylcholinesterase (BChE) is widely distributed in various tissues and highly implicated in several important human diseases, especially Alzheimer's disease (AD). However, the role of BChE in AD is still controversial, which may be partially attributed to the lack of a direct tool for real-time and noninvasive monitoring of BChE in in vivo. Here, we report three rationally designed near-infrared fluorogenic probes that possess excellent discrimination for butyrylcholinesterase (BChE) over the related enzyme acetylcholinesterase (AChE). The refined probe, BChE-NIRFP, not only functions as an exquisite substrate for BChE in in vitro assays but also represents a superb "signal-on" imaging tool to real-time track BChE levels in human cells, zebrafish, and a mouse model of AD. A further application of BChE-NIRFP to identify the cellular mechanism reveals that Aβ fibrils and insulin resistance may be important contributors to the abnormally elevated BChE levels observed during AD progression. Based on the results from the present study, this new probe is a valuable tool for basic and clinical research designed to obtain a complete understanding of the physiological roles of BChE in diverse human diseases, particularly AD.

A molecular approach to rationally constructing specific fluorogenic substrates for the detection of acetylcholinesterase activity in live cells, mice brains and tissues

“…Another inevitable drawback is that the current substrate (i.e., the acetyl group) for the detection for AChE activity always suffers from the interference of butyrylcholinesterase (BChE) and carboxylesterase (CE) due to their similar catalytic mechanism to that of AChE. [40][41][42] Recently, two groups proposed uorescent probes using the dimethyl-carbamate unit for the detection of AChE activity. 43,44 However, this carbamate moiety may react with CE.…”

Highly selective and sensitive colorimetric chemosensor based on tricarboyanine for detection of Ag+ in industrial wastewater

“…It was synthesized according to the reported literature [50]. Specifically, Fresh distilled dimethylformamide (DMF) (10 mL, 135 mmol) was added into a 100 mL two-neck round flask under argon atmosphere.…”

“…b1 was filtered and washed with water, followed by drying in vacuum as yellow solid (actual yield = 3.10 g; theoretical yield = 4.55 g; yield% = 68%). It was synthesized according to the reported literature [50]. Typically, 2,3,3-trimethylindolenine (3.18 g, 20 mmol) was dissolved in toluene (5 mL), iodoethane (3.12 g, 20 mmol) was then added dropwise at R.T..…”

Development of potent reversible selective inhibitors of butyrylcholinesterase as fluorescent probes

“…A tacrine-based fluorescent inhibitor with high affinity towards both AChE and BChE has been described, and this was shown to stain Ab plaques when used as a probe for histochemical staining of brain tissue 12 . Besides probes developed from inhibitors, two recently described BChE probes were developed as substrates for BChE 13,14 . BChE converts the nonfluorescent substrate to highly fluorescent products.…”

“…BChE converts the nonfluorescent substrate to highly fluorescent products. Furthermore, both probes are poor substrates for AChE or other types of esterases, thus providing high selectivity towards BChE 13,14 . However, no BChE-selective probes derived from inhibitors were reported to date.…”