Cobalt oxide nanoparticles induce neurodevelopmental toxicity through ferritinophagy-mediated ferroptosis: Evidence from zebrafish and cell models.

Cobalt oxide nanoparticles (Co3O4 NPs) are widely used in lithium batteries and semiconductors, and are often detected in water, soil, and occupational environments. While cobalt ions are linked to neurodegenerative diseases, the neurodevelopmental toxicity of Co3O4 NPs remains poorly understood. Ferroptosis, a process regulated by iron homeostasis, can be triggered by ferrous overload through ferritinophagy. This study explores how Co3O4 NPs induce ferritinophagy and their role in neurodevelopmental toxicity. Zebrafish larvae exposed to Co3O4 NPs at concentrations of 0, 5, and 50 mg/L for up to 120 h post-fertilization (hpf) exhibited dose-dependent developmental toxicity, including delayed hatching, increased malformations, and impaired motor behavior. Transgenic zebrafish models demonstrated neuronal shortening, reduced fluorescence, and altered neurotransmitter profiles, as supported by liquid chromatography-tandem mass spectrometry. Co3O4 NPs induced oxidative stress, leading to iron overload, lipid peroxidation (elevated MDA, depleted glutathione), and ferritinophagy activation, as evidenced by changes in genes and proteins related to iron metabolism (trf, fpn, slc7a11) and ferroptosis (GPX4, ACSL4, FTH1, NCOA4). Ferritinophagy was further confirmed using autophagy inhibitors, demonstrating its role in neurotoxicity. Additionally, Vitamin E (d-α-tocopherol), a lipid-soluble antioxidant that suppresses lipid peroxidation, reduced neurodevelopmental abnormalities, supporting that Co3O4 NP-induced toxicity occurs through ferritinophagy-mediated ferroptosis, leading to neurotransmitter dysregulation. These findings were corroborated in human neuroblastoma cells (SH-SY5Y/SK-N-SH). In conclusion, Co3O4 NPs disrupt iron homeostasis, activate ferritinophagy, and induce ferroptosis, resulting in neurotransmitter dysregulation and neurodevelopmental toxicity. These results provide new insights for assessing the neurodevelopmental toxicity and environmental risk of Co3O4 NPs and similar nanomaterials.