Development of bishydrazide-based fluorescent probes for the imaging of cellular peroxynitrite (ONOO - ) during ferroptosis.

Peroxynitrite (ONOO - ) is a critical ROS in living systems, and could induce lipid peroxidation which is the driver of ferroptotic cell death. Therefore, precise and rapid detection of cellular ONOO - is critical for the deep study of the biological functions of ONOO - during ferroptosis. Herein, we developed fluorescent probes (Rh-1, Rh-2 and Rh-3) for the rapid detection of intracellular ONOO - during ferroptosis. These probes used bishydrazide groups as the reactive sites for ONOO - . The response of these probes to ONOO - resulted in the production of the emissive xanthene fluorophore, providing a marked enhancement in the fluorescence intensity at 561 nm. The probe Rh-3 exhibited prominent selectivity and sensitivity towards ONOO - . Bioimaging experiments suggested that Rh-3 could be applied to image exogenous and endogenous ONOO - in living cells. By fluorescence imaging, it was demonstrated that erastin-induced ferroptosis caused increased levels of the endogenous ONOO - , and ferrostatin-1 (Fer-1) and vitamin E (VE) could markedly inhibit the excessive production of ONOO - during ferroptosis in living cells.