Copper–zinc alloy induces fdx1 and dlat dependent cuproptosis in Cryptocaryon irritans via mitochondrial metabolic collapse

Abstract

Cryptocaryon irritans is a devastating marine parasite, necessitating the development of effective control strategies. While copper–zinc alloy (CZA) exhibits potent antiparasitic activity, its underlying mechanism of action remains unclear. Here, we demonstrate that CZA eliminates C. irritans primarily by inducing ferredoxin reductase 1 (fdx1)-dependent cuproptosis. Pharmacological inhibition assays revealed that blocking cuproptosis significantly rescued parasite viability (survival rate: 90%), whereas suppressing oxidative stress provided only partial protection (75%). Crucially, inhibiting other regulated cell death pathways, including apoptosis, ferroptosis, and necroptosis, failed to improve survival. CZA exposure triggered severe mitochondrial dysfunction, characterized by loss of membrane potential, a fivefold depletion of ATP, and structural damage, alongside intracellular copper ion accumulation and tricarboxylic acid (TCA) cycle disruption. Transcriptomic and functional analyses identified fdx1 and dihydrolipoamide S-acetyltransferase (dlat) as key mediators; RNA interference-mediated knockdown of these genes increased parasite survival by 70%. Notably, only cuproptosis inhibition restored mitochondrial integrity and metabolic homeostasis, indicating that while oxidative stress is an inevitable downstream component of the lethal cascade, it acts as a secondary consequence rather than the primary initiator of cell death. These findings establish that CZA exerts its antiparasitic effects through copper-induced mitochondrial metabolic collapse and fdx1-dependent cuproptosis, providing a mechanistic foundation for copper-based therapies against C. irritans.

Keywords

Copper-zinc alloy / Parasitosis / Mitochondrial dysfunction / Cuproptosis / Oxidative stress

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