School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China.
Academy of Integrative Medicine, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian 116044, China.
Toxicology. 2019 Apr 1;417:64-73. doi: 10.1016/j.tox.2019.02.011. Epub 2019 Feb 21.
The activation of NADPH oxidase contributes to dopaminergic neurodegeneration induced by paraquat and maneb, two concurrently used pesticides in agriculture. However, the mechanisms remain unclear. Ferroptosis, a recently recognized form of regulated cell death, has been implicated in the pathogenesis of multiple neurodegenerative diseases. This study is designed to investigate whether ferroptosis is involved in NADPH oxidase-regulated dopaminergic neurotoxicity. In vitro study showed that paraquat and maneb exposure induced ferroptosis in SHSY5Y dopaminergic cells, which was associated with activation of NADPH oxidase. Inhibition of NADPH oxidase by apocynin or diphenyleneiodonium (DPI), two widely used NADPH oxidase inhibitors mitigated paraquat and maneb-induced ferroptotic cell death. Consistently, stimulating activation of NADPH oxidase by phorbol myristate acetate (PMA) or supplementation of HO exacerbated ferroptosis in paraquat and maneb-treated SHSY5Y cells. Mechanistic inquiry revealed that NADPH oxidase activation elicited lipid peroxidation, a main driving force for ferroptosis, since both apocynin and DPI greatly reduced MDA contents and simultaneously recovered levels of glutathione and glutathione peroxidase 4 (GPX4) in paraquat and maneb-treated SHSY5Y cells. The contribution of NADPH oxidase on ferroptosis of dopaminergic neurons was further verified in vivo by showing reduced iron content, lipid peroxidation, neuroinflammation and dopaminergic neurodegeneration, which are all involved in ferroptosis, in combined apocynin and paraquat and maneb-treated mice compared with paraquat and maneb alone group. Altogether, our findings showed that NADPH oxidase contributed to paraquat and maneb-induced dopaminergic neurodegeneration through ferroptosis, providing a novel mechanism for pesticide-induced dopaminergic neurotoxicity.
烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的激活导致百草枯和代森锰锌这两种农业上同时使用的农药诱导的多巴胺能神经退行性变。然而，其机制尚不清楚。铁死亡是一种最近被认识到的细胞死亡形式，已被牵涉到多种神经退行性疾病的发病机制中。本研究旨在探讨铁死亡是否参与 NADPH 氧化酶调节的多巴胺能神经毒性。体外研究表明，百草枯和代森锰锌暴露诱导 SHSY5Y 多巴胺能细胞发生铁死亡，这与 NADPH 氧化酶的激活有关。NADPH 氧化酶抑制剂鱼藤酮或二苯基碘（DPI）抑制 NADPH 氧化酶，减轻了百草枯和代森锰锌诱导的铁死亡细胞死亡。同样，佛波醇肉豆蔻酸酯（PMA）刺激 NADPH 氧化酶的激活或补充 H2O2 加剧了百草枯和代森锰锌处理的 SHSY5Y 细胞中的铁死亡。机制研究表明，NADPH 氧化酶的激活引发了脂质过氧化，这是铁死亡的主要驱动力，因为鱼藤酮和 DPI 都大大降低了 MDA 的含量，同时恢复了百草枯和代森锰锌处理的 SHSY5Y 细胞中的谷胱甘肽和谷胱甘肽过氧化物酶 4（GPX4）水平。体内研究通过显示减少铁含量、脂质过氧化、神经炎症和多巴胺能神经退行性变，进一步证实了 NADPH 氧化酶对多巴胺能神经元铁死亡的贡献，这些变化都涉及铁死亡，在联合使用鱼藤酮和百草枯和代森锰锌的小鼠中比单独使用百草枯和代森锰锌的组中更为明显。总之，我们的研究结果表明，NADPH 氧化酶通过铁死亡导致百草枯和代森锰锌诱导的多巴胺能神经退行性变，为农药诱导的多巴胺能神经毒性提供了一种新的机制。
