十字花科富含的饮食，特别是西兰花，与降低各类癌症、心血管疾病和2型糖尿病的风险相关。硫辛烷（SF）是一种含硫的西兰花代谢物，已被鉴定为介导这些健康益处的主要生物活性化合物。硫辛烷是一种有效激活转录因子核因子样红细胞生成2（NRF2）的膳食物质，NRF2是细胞抗氧化能力的主要调节因子，负责诱导细胞保护性基因的表达，但其在葡萄糖稳态中的作用尚不清楚。在本研究中，我们设定了一个假设，即硫辛烷通过诱导人肝细胞癌HepG2中的NRF2来调控葡萄糖代谢，并改善葡萄糖过载及其导致的氧化应激。将HepG2细胞暴露于不同葡萄糖浓度：基础（5.5毫摩尔/升）和高葡萄糖（25毫摩尔/升），同时添加生理浓度的硫辛烷（10微摩尔/升）。结果显示，硫辛烷上调谷胱甘肽（GSH）合成基因的表达，并显著增加了还原型谷胱甘肽的水平。利用标记的葡萄糖和谷氨酰胺实验测量代谢通量的方法，发现硫辛烷通过减少谷氨酸向TCA循环的流入、增加来自培养基的半胱氨酸的摄取来重定向细胞内对甘氨酸和谷氨酸的利用，可能是为了支持谷胱甘肽的合成。此外，硫辛烷改变了生成NADPH（氧化还原酶反应所需的辅因子）的途径，即糖磷酸戊糖途径和1C-代谢，从而将葡萄糖从糖酵解中重定向至PPP，将蛋氨酸重定向至甲基化底物。最后，通过利用CRISPR-Cas9基因编辑技术生成的NRF2-KD HepG2细胞进行转录组和靶向代谢组学液相色谱-质谱分析揭示了上述代谢效应是通过NRF2介导的。这些结果表明，十字花科饮食的抗氧化性质与其代谢益处密切相关。版权所有 © 2023作者。由Elsevier B.V.出版。保留所有权利。

Cruciferous-rich diets, particularly broccoli, have been associated with reduced risk of developing cancers of various sites, cardiovascular disease and type-2 diabetes. Sulforaphane (SF), a sulfur-containing broccoli-derived metabolite, has been identified as the major bioactive compound mediating these health benefits. Sulforaphane is a potent dietary activator of the transcription factor Nuclear factor erythroid-like 2 (NRF2), the master regulator of antioxidant cell capacity responsible for inducing cytoprotective genes, but its role in glucose homeostasis remains unclear. In this study, we set to test the hypothesis that SF regulates glucose metabolism and ameliorates glucose overload and its resulting oxidative stress by inducing NRF2 in human hepatoma HepG2 cells. HepG2 cells were exposed to varying glucose concentrations: basal (5.5 mM) and high glucose (25 mM), in the presence of physiological concentrations of SF (10 μM). SF upregulated the expression of glutathione (GSH) biosynthetic genes and significantly increased levels of reduced GSH. Labelled glucose and glutamine experiments to measure metabolic fluxes identified that SF increased intracellular utilisation of glycine and glutamate by redirecting the latter away from the TCA cycle and increased the import of cysteine from the media, likely to support glutathione synthesis. Furthermore, SF altered pathways generating NADPH, the necessary cofactor for oxidoreductase reactions, namely pentose phosphate pathway and 1C-metabolism, leading to the redirection of glucose away from glycolysis and towards PPP and of methionine towards methylation substrates. Finally, transcriptomic and targeted metabolomics LC-MS analysis of NRF2-KD HepG2 cells generated using CRISPR-Cas9 genome editing revealed that the above metabolic effects are mediated through NRF2. These results suggest that the antioxidant properties of cruciferous diets are intricately connected to their metabolic benefits.Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.