Cuproptosis tracker: Visualizing organelle dynamics with a dual-targeted fluorescent probe

Cuproptosis often interacts with mitochondrial (Mito) dysfunction and lipid droplets (LDs) metabolism disturbances, thus resulting in programmed cell death, whereas their dynamic interaction lacks a rational analyzing tool. Herein, we show a Mito-LDs dual-targeted fluorescent reporter (MLR) for tracking the Mito-LDs interaction during cuproptosis by dynamic monitoring of intracellular sulfur dioxide (SO₂) dynamics. MLR integrates a coumarin-derived SO₂-responsive core linked via piperazine to a benzopyronium Mitol anchor, enabling one-step synthesis with exceptional sensitivity (0.34 μM) and rapid response (<10 s). Live-cell imaging demonstrated MLR's SO₂-triggered translocation from Mito to LDs during cuproptosis, directly visualizing inter-organelle communication. Dual fluorescence channel imaging associated SO₂ fluctuations with Mito-LDs targeting, revealing the interaction between LDs-Mito during Cu²⁺ and elesclomol (ES) induced apoptosis. In addition to imaging, MLR-based test strips and hydrogels can achieve rapid (<1 min) on-site SO₂ detection. As a dual-organelle tracer for cuproptosis, MLR overcomes single-target probe limitations, offering a transformative platform to analyze spatiotemporal organelle dynamics for advancing diagnostic tools development.