First evidence of CuPANotic cell death in fish gut upon environmentally relevant co-exposure to Copper and PVC microplastics

• This study reveals CuPANoptosis, integrating cuproptosis and PANoptosis in fish. • PVC-MPs increased gut copper load by 1.6–1.9-fold, enhancing uptake and retention. • FDX1-driven lipoylation collapse induced mitochondrial dysfunction and cuproptosis. • Apoptosis, pyroptosis, and necroptosis converged into a unified death axis. • Microplastic-metal synergy amplifies toxicity, raising critical ecological concerns. Microplastic-metal interactions represent a critical but underexplored dimension of aquatic ecotoxicology. Here, we provide the first validation of a novel CuPANoptosis (Cuproptosis and PANoptosis) paradigm in fish, uncovering how polyvinyl chloride microplastics (PVC-MPs) intensifies copper (Cu²⁺)-induced toxicity in Channa punctatus . Fish were exposed to environmentally relevant concentrations of PVC-MPs (0.5 mg/L) and copper (0.85 mg/L), individually and in combination, for 60 days. PVC-MPs acted as potent vectors, enhancing copper bioavailability, tissue retention, and translocation across intestinal barriers, resulting in exacerbated oxidative stress and mitochondrial dysfunction. Mechanistically, FDX1-mediated Cu⁺ reduction accelerated abnormal protein lipoylation and aggregation, collapsing TCA cycle function and triggering cuproptosis. Strikingly, this cuproptotic activation integrated with apoptotic, pyroptotic, and necroptotic pathways, forming an interconnected programmed cell death circuitry ‘CuPANoptosis’. The co-exposure group exhibited maximal ROS accumulation, lipid peroxidation, GSH depletion, and severe disruption of intestinal architecture, including vacuolization, villi detachment, and widespread cellular damage, with all key alterations showing high statistical significance ( p < 0.05) . Transcriptional and protein-level analyses revealed upregulation of key mediators including fdx1, dlat, dlst, bax, nlrp3, ripk1 , and caspases , validating synchronized activation of multiple cell death pathways. These findings highlight that PVC-MPs act as dynamic carriers amplifying copper-induced toxicity and unveil a previously unrecognized mechanism of gut injury. Collectively, our study provides the first transformative framework for understanding MP-metal synergy in aquatic systems, emphasizing urgent ecological risks and the need for targeted mitigation strategies.