Stress-Induced Covalent Labelling and Tandem Fluorogenicity for Tri-State Warning of Fluohepatotoxicity-Associated Mitochondrial Damage

Abstract Precisely shedding light on mitochondrial damage upon stress action is essential for deciphering mitochondria-related diseases and advancing mitochondria-targeted therapeutics. Traditional commercial and synthetic indicators via electrostatic accumulation and in situ pre-labelling strategies are often unreliable for persistent damage monitoring and unworkable to evaluate mitochondrial health status. Moreover, they are nonspecific for individual stress events. Herein, we report a stress-activatable post-labelling strategy to track mitochondria damage by a specific stressor in a tandemly fluorogenic manner. As a proof of concept, a tri-state warning beacon dedicated to mitochondria damage by fluoride stress has been rationally designed based on a chameleon-like unimolecular scaffold with stress-dependent protein-anchoring capability, enabling cascade visualization of fluoride invasion and the relevant upregulated peroxynitrite inside mitochondria that serves as both a primary mediator of nitrosative stress and a biomarker of hepatotoxicity, visually dissecting that peroxynitrite-mediated excessive mitochondrial nitrosative stress plays a critical role in fluohepatotoxicity for the first time. Our proposal would be versatile in deriving precise molecular tools alerting different types of stress-induced mitochondrial damage, helpful for improving the investigation of mitochondria stress-related pathophysiology and molecular theranostics.