Vitamin E hydroquinone is an endogenous regulator of ferroptosis via redox control of 15-lipoxygenase
作者:Andrew Hinman、Charles R. Holst、Joey C. Latham、Joel J. Bruegger、Gözde Ulas、Kevin P. McCusker、Akiko Amagata、Dana Davis、Kevin G. Hoff、Amanda H. Kahn-Kirby、Virna Kim、Yuko Kosaka、Edgar Lee、Stephanie A. Malone、Janet J. Mei、Steve James Richards、Veronica Rivera、Guy Miller、Jeffrey K. Trimmer、William D. Shrader
DOI:10.1371/journal.pone.0201369
日期:——
Ferroptosis is a form of programmed cell death associated with inflammation, neurodegeneration, and ischemia. Vitamin E (alpha-tocopherol) has been reported to prevent ferroptosis, but the mechanism by which this occurs is controversial. To elucidate the biochemical mechanism of vitamin E activity, we systematically investigated the effects of its major vitamers and metabolites on lipid oxidation and ferroptosis in a striatal cell model. We found that a specific endogenous metabolite of vitamin E, alpha-tocopherol hydroquinone, was a dramatically more potent inhibitor of ferroptosis than its parent compound, and inhibits 15-lipoxygenase via reduction of the enzyme’s non-heme iron from its active Fe3+ state to an inactive Fe2+ state. Furthermore, a non-metabolizable isosteric analog of vitamin E which retains antioxidant activity neither inhibited 15-lipoxygenase nor prevented ferroptosis. These results call into question the prevailing model that vitamin E acts predominantly as a non-specific lipophilic antioxidant. We propose that, similar to the other lipophilic vitamins A, D and K, vitamin E is instead a pro-vitamin, with its quinone/hydroquinone metabolites responsible for its anti-ferroptotic cytoprotective activity.
铁细胞凋亡是一种与炎症、神经变性和缺血有关的程序性细胞死亡。据报道,维生素 E(α-生育酚)可防止铁猝死,但其发生机制尚存争议。为了阐明维生素 E 活性的生化机制,我们在纹状体细胞模型中系统研究了维生素 E 的主要维生素和代谢物对脂质氧化和铁氧化的影响。我们发现,维生素 E 的一种特定内源性代谢物--α-生育酚对苯二酚,是一种比其母体化合物更有效的铁氧化抑制剂,它通过将酶的非血红素铁从活性的 Fe3+ 状态还原为非活性的 Fe2+ 状态来抑制 15-脂氧合酶。此外,维生素 E 的一种不可代谢的异构类似物保留了抗氧化活性,既不能抑制 15-脂氧合酶,也不能阻止铁跃迁。这些结果对维生素 E 主要作为非特异性亲脂抗氧化剂的流行模式提出了质疑。我们认为,与其他亲脂性维生素 A、D 和 K 相似,维生素 E 也是一种维生素原,其醌/氢醌代谢物具有抗铁细胞生成的细胞保护活性。