Toxic Switch and Key Effectors of Cu in Zebrafish Gills: Coupling Single-Cell RNA Sequencing and Redox Imaging

) serve as the potential biomarkers of Cu pollution. The novel in situ fluorescence probes enabled simultaneous visualization of Cu(I)/Cu(II) spatial distribution, validating cluster-specific Cu redox states dynamics. The most prominent toxic effects observed were the respiratory inhibition and epithelial hyperplasia. Intriguingly, Cu overload reprogrammed intercellular communication networks with severe pathological injury. Overall, these findings illustrate an essential role of redox state switch in ecological risk of Cu in aquatic organisms.