Imaging of Formaldehyde in Live Cells and Daphnia magna via Aza-Cope Reaction Utilizing Fluorescence Probe With Large Stokes Shifts.

Mingwang Yang,Jianjun Du,Saran Long,Jia Wang,Xiaojun Peng,Jiangli Fan

doi:10.3389/fchem.2018.00488

Abstract

Formaldehyde (FA), a highly reactive carbonyl species, plays significant role in physiological and pathological functions. However, elevated FA will lead to cognitive impairments, memory loss and various neurodegenerative diseases due to its potent DNA and protein cross-linking mechanisms. In this work, a fluorescence probe, BD-CHO, based on benz-2-oxa-1, 3- diazole (BD) skeleton, was designed and synthesized for detection of FA via Aza-Cope reaction with high selectivity and large Stokes shifts (about 118 nm). BD-CHO was successfully applied to monitor the changes FA level in living cells, and kidney tissues of mice. Importantly it was the first time that BD-CHO was used for visualizing exogenous FA changes in Daphnia magna through fluorescence microscopy, demonstrating its potential application for studies of biological processes associated with FA.

Highlights

Formaldehyde (FA) is a common environmental toxin and endogenously produced through metabolism of amino acids or xenobiotics catalyzed by demethylases and oxidases, such as lysine-specific demethylase 1 (LDS1) (Shi et al, 2004) and semicarbazide-sensitive amine oxidase (SSAO) (O’Sullivan, 2004)
To design selective and sensitive fluorescence probe for the FA detection, we focus on homoallylamine trigger which can specially react with FA and produce an electron-withdrawing aldehyde group via an Aza-Cope rearrangement reaction
Dimethylamine group was introduced as an electron-donating group (EDG) and homoallylic amine as FA-recognized group

Summary

Introduction

Formaldehyde (FA) is a common environmental toxin and endogenously produced through metabolism of amino acids or xenobiotics catalyzed by demethylases and oxidases, such as lysine-specific demethylase 1 (LDS1) (Shi et al, 2004) and semicarbazide-sensitive amine oxidase (SSAO) (O’Sullivan, 2004). We report an Aza-Cope reaction-based fluorescence probe (BD-CHO) for FA (Figure 1). For imaging exogenous FA, the culture media of HepG2 cells was replaced with 2 mL of serum-free DMEM containing 10 μM fluorescent probe (from 2 mM stock in DMSO) and the cells were incubated for 30 min.

Results

Conclusion