A novel alpha-ketoamide reactivity-based two-photon fluorogenic probe for visualizing peroxynitrite in Parkinson's disease models

Peroxynitrite (ONOO-) contributes to oxidative stress and neurodegeneration in Parkinson's disease (PD). Developing a peroxynitrite probe would enable in situ visualization of the overwhelming ONOO- flux and understanding of the ONOO- stress-induced neuropathology of PD. Herein, a novel alpha-ketoamide-based fluorogenic probe (DFlu) was designed for ONOO- monitoring in multiple PD models. The results demonstrated that DFlu exhibits a fluorescence turn-on response to ONOO- with high specificity and sensitivity. The efficacy of DFlu for intracellular ONOO- imaging was demonstrated systematically. The results showed that DFlu can successfully visualize endogenous and exogenous ONOO- in cells derived from chemical and biochemical routes. More importantly, the two-photon excitation ability of DFlu has been well demonstrated by monitoring exogenous/endogenous ONOO- production and scavenging in live zebrafish PD models. This work provides a reliable and promising alpha-ketoamide-based optical tool for identifying variations of ONOO- in PD models.