Intracellular copper redox modulation disrupts ROS–Ca²⁺ amplification in an ATP7B-deficient zebrafish model of Wilson’s disease

Excess labile copper catalyzes Fenton-type redox cycling, amplifying reactive oxygen species (ROS) and disrupting mitochondrial and calcium homeostasis. In Wilson’s disease (WD), ATP7B deficiency leads to hepatic copper accumulation and progressive redox-driven tissue injury. Here, we investigated whether intracellular copper modulation interrupts ROS–Ca²⁺ amplification cascades and restores cellular, functional and organ-level homeostasis. Copper challenge in human epithelial, fibroblast, and proliferative cell lines induced dose-dependent ROS accumulation, delayed intracellular Ca²⁺ transients, and suppression of metabolic activity. Pre-treatment with Telomir-Zn (0.1–5 µM) significantly reduced DCFH-DA ROS signals following Cu²⁺ or H₂O₂ exposure, attenuated Fluo-8–detected Ca²⁺ flux amplitude and preserved mitochondrial-associated metabolic viability. These effects were observed across cell types, consistent with modulation of labile redox-active copper pools. In ATP7B^C271X zebrafish, oral Telomir-Zn (1.5–5 ng) reduced hepatic copper levels, improved locomotor performance, normalized AST, ALT and bilirubin, attenuated hepatorenal degeneration, and significant survival in a dose-dependent manner. Histological analyses demonstrated reduced necrosis and inflammatory infiltration relative to untreated mutants. Collectively, these findings demonstrate that intracellular copper redox modulation disrupts ROS–Ca²⁺ feedback amplification and mitigates mitochondrial-associated injury in ATP7B deficiency. Targeting labile copper-driven redox cascades may represent a mechanistically distinct strategy for restoring tissue homeostasis in copper-overload disorders.