Molecular visualizing and quantifying immune-associated peroxynitrite fluxes in phagocytes and mouse inflammation model.

Reactions of peroxynitrite (ONOO) with biomolecules can lead to cytotoxic and cytoprotective events. Due to the difficulty of directly and unambiguously measuring its levels, most of the beneficial effects associated with ONOO in vivo remain controversial or poorly characterized. Recently, optical imaging has served as a powerful noninvasive approach to studying ONOO in living systems. However, ratiometric probes for ONOO are currently lacking. Herein, we report the design, synthesis, and biological evaluation of F, a novel fluorescence indicator that relies on ONOO-induced diene oxidation. The remarkable sensitivity, selectivity, and photostability of F enabled us to visualize basal ONOO in immune-stimulated phagocyte cells and quantify its generation in phagosomes by high-throughput flow cytometry analysis. With the aid of in vivo ONOO imaging in a mouse inflammation model assisted by F, we envision that F will find widespread applications in the study of the ONOO biology associated with physiological and pathological processes in vitro and in vivo.