A Small-Molecule Drug for the Self-Checking of Mitophagy

Mitophagy that disrupt mitochondrial membrane potential (MMP), represents a critical focus in pharmacology. However, the discovery and evaluation of MMP-disrupting drugs are often hampered using commercially available marker molecules that target similar or identical zones. These markers can significantly interfere with, obscure, or amplify the functional effects of MMP-targeting drugs, frequently leading to clinical failures. In response to this challenge, we propose a "one-two punch" drug design strategy that integrates both target-zone drug functionality and non-target zone biological reporting within a single small-molecule drug. We have developed a novel mitophagy self-check drug (MitoSC) that exhibits dual-color and dual-localization properties. The functional component of this system is a variable MitoSC that disrupts MMP homeostasis, thereby inducing mitophagy. Upon activation, this component transforms into a blue-fluorescent monomer (MitoSC-fun) specifically within the mitochondrial target zone. The biological reporting component is represented by a red-fluorescent monomer (MitoSC-rep) that localizes to lysosomes, the non-target zone. As mitophagy progresses, the fluorescent signals from MitoSC-rep (lysosomes) and MitoSC-fun (mitochondria) converge, enabling real-time monitoring of the mitophagy process. Our findings underscore the potential of a single-molecule drug to exert target-zone specific actions while simultaneously providing non-target zone self-checking, offering a new perspective for drug design.