Jia Yi-Chen, Hao Xiangyu, Zhu Bao Ting
Shenzhen Key Laboratory of Steroid Drug Discovery and Development, School of Medicine, The Chinese University of Hong Kong, Shenzhen, China.
Shenzhen Key Laboratory of Steroid Drug Discovery and Development, School of Medicine, The Chinese University of Hong Kong, Shenzhen, China; Shenzhen Bay Laboratory, Shenzhen, China.
J Pharmacol Exp Ther. 2025 Jun 2;392(7):103620. doi: 10.1016/j.jpet.2025.103620.
Oxidative ferroptotic cell death can be selectively induced in cultured cells by chemicals like erastin (an inhibitor of system Xc) and RSL3 (an inhibitor of glutathione peroxidase 4). It was recently revealed that protein disulfide isomerase (PDI) is an upstream mediator of chemically-induced ferroptosis and thus also a drug target for ferroptosis protection. Here, we report that N-methyldopamine (MD), a metabolite of dopamine, can protect against erastin- and RSL3-induced ferroptosis in cultured cells, including rat hepatocytes and rat cardiomyocytes. Ibopamine, a prodrug that can release MD in vivo, also exhibits a similar cytoprotective effect in cultured cells in vitro. Mechanistically, MD can bind to PDI in live cells, and can also inhibit PDI's catalytic activities in vitro, likely through covalent interactions. Inhibition of PDI by MD markedly abrogates chemically-induced, PDI-mediated nitric oxide synthase (NOS) dimerization (ie, catalytic activation) and nitric oxide (NO) accumulation, which is followed by reduced buildup of cellular reactive oxygen species (ROS) and lipid-ROS. These changes resulting from the inhibition of PDI-mediated NOS activation and reduction in cellular NO and ROS/lipid-ROS levels jointly contribute, in a predominant manner, to the prevention of chemically-induced ferroptosis by MD. In addition, animal studies showed that MD and ibopamine each can prevent acetaminophen-induced liver injury in mice. In conclusion, the results of this study demonstrate that MD can prevent chemically-induced ferroptosis both in vitro and in vivo through inhibition of PDI-mediated NOS dimerization and NO accumulation. SIGNIFICANCE STATEMENT: It was recently shown that PDI is a pivotal upstream mediator of chemically-induced oxidative ferroptosis and thus a drug target for ferroptosis protection. This study reports that N-methyldopamine, a metabolite of dopamine, is an inhibitor of PDI, and can prevent chemically-induced ferroptosis both in vitro and in vivo. Ibopamine, a prodrug designed to release N-methyldopamine following oral administration, is also highly effective as a cytoprotective agent. This work reveals the PDI-mediated mechanism of cytoprotection by N-methyldopamine and its prodrug ibopamine.
氧化型铁死亡细胞死亡可通过如艾拉司丁（一种Xc系统抑制剂）和RSL3（一种谷胱甘肽过氧化物酶4抑制剂）等化学物质在培养细胞中被选择性诱导。最近有研究表明，蛋白质二硫键异构酶（PDI）是化学诱导铁死亡的上游介质，因此也是铁死亡保护的药物靶点。在此，我们报告多巴胺的代谢产物N - 甲基多巴胺（MD）可保护培养细胞（包括大鼠肝细胞和大鼠心肌细胞）免受艾拉司丁和RSL3诱导的铁死亡。异波帕明是一种可在体内释放MD的前药，在体外培养细胞中也表现出类似的细胞保护作用。从机制上讲，MD可在活细胞中与PDI结合，并且在体外也能抑制PDI的催化活性，可能是通过共价相互作用。MD对PDI的抑制显著消除了化学诱导的、PDI介导的一氧化氮合酶（NOS）二聚化（即催化激活）和一氧化氮（NO）积累，随后细胞活性氧（ROS）和脂质ROS的积累减少。由抑制PDI介导的NOS激活以及细胞内NO和ROS/脂质ROS水平降低所导致的这些变化，共同以主要方式促成了MD对化学诱导铁死亡的预防。此外，动物研究表明MD和异波帕明均可预防对乙酰氨基酚诱导的小鼠肝损伤。总之，本研究结果表明MD可通过抑制PDI介导的NOS二聚化和NO积累在体外和体内预防化学诱导的铁死亡。意义声明：最近的研究表明，PDI是化学诱导的氧化型铁死亡的关键上游介质，因此是铁死亡保护的药物靶点。本研究报告多巴胺的代谢产物N - 甲基多巴胺是PDI的抑制剂，可在体外和体内预防化学诱导的铁死亡。异波帕明是一种口服给药后可释放N - 甲基多巴胺的前药，作为细胞保护剂也非常有效。这项工作揭示了N - 甲基多巴胺及其前药异波帕明通过PDI介导的细胞保护机制。
