Chi Jen-Tsan, Lin Chao Chieh, Lin Yi-Tzu, Chen Ssu-Yu, Setayeshpour Yasaman, Chen Yubin, Dunn Denise, Soderblom Erik, Zhang Guo-Fang, Filonenko Valeriy, Jeong Suh Young, Floyd Scott, Hayflick Susan, Gout Ivan
Duke University.
Duke University School of Medicine.
Res Sq. 2024 Jun 18:rs.3.rs-4522617. doi: 10.21203/rs.3.rs-4522617/v1.
The Cystine-xCT transporter-Glutathione (GSH)-GPX4 axis is the canonical pathway to protect against ferroptosis. While not required for ferroptosis-inducing compounds (FINs) targeting GPX4, FINs targeting the xCT transporter require mitochondria and its lipid peroxidation to trigger ferroptosis. However, the mechanism underlying the difference between these FINs is still unknown. Given that cysteine is also required for coenzyme A (CoA) biosynthesis, here we show that CoA supplementation specifically prevents ferroptosis induced by xCT inhibitors but not GPX4 inhibitors. We find that, auranofin, a thioredoxin reductase inhibitor, abolishes the protective effect of CoA. We also find that CoA availability determines the enzymatic activity of thioredoxin reductase, but not thioredoxin. Importantly, the mitochondrial thioredoxin system, but not the cytosolic thioredoxin system, determines CoA-mediated ferroptosis inhibition. Our data show that the CoA regulates the enzymatic activity of mitochondrial thioredoxin reductase (TXNRD2) by covalently modifying the thiol group of cysteine (CoAlation) on Cys-483. Replacing Cys-483 with alanine on TXNRD2 abolishes its enzymatic activity and ability to protect cells from ferroptosis. Targeting xCT to limit cysteine import and, therefore, CoA biosynthesis reduced CoAlation on TXNRD2, an effect that was rescued by CoA supplementation. Furthermore, the fibroblasts from patients with disrupted CoA metabolism demonstrate increased mitochondrial lipid peroxidation. In organotypic brain slice cultures, inhibition of CoA biosynthesis leads to an oxidized thioredoxin system, mitochondrial lipid peroxidation, and loss in cell viability, which were all rescued by ferrostatin-1. These findings identify CoA-mediated post-translation modification to regulate the thioredoxin system as an alternative ferroptosis protection pathway with potential clinical relevance for patients with disrupted CoA metabolism.
胱氨酸-xCT转运体-谷胱甘肽（GSH）-GPX4轴是抵御铁死亡的经典途径。虽然针对GPX4的铁死亡诱导化合物（FINs）引发铁死亡不需要该途径，但针对xCT转运体的FINs需要线粒体及其脂质过氧化来触发铁死亡。然而，这些FINs之间差异的潜在机制仍不清楚。鉴于半胱氨酸也是辅酶A（CoA）生物合成所必需的，我们在此表明补充CoA可特异性预防由xCT抑制剂而非GPX4抑制剂诱导的铁死亡。我们发现，金诺芬，一种硫氧还蛋白还原酶抑制剂，可消除CoA的保护作用。我们还发现CoA的可用性决定硫氧还蛋白还原酶的酶活性，而非硫氧还蛋白的酶活性。重要的是，线粒体硫氧还蛋白系统而非胞质硫氧还蛋白系统决定CoA介导的铁死亡抑制。我们的数据表明，CoA通过共价修饰Cys-483上半胱氨酸的硫醇基团（CoAlation）来调节线粒体硫氧还蛋白还原酶（TXNRD2）的酶活性。用丙氨酸替换TXNRD2上的Cys-483可消除其酶活性以及保护细胞免受铁死亡的能力。靶向xCT以限制半胱氨酸的摄入，从而减少CoA生物合成，降低了TXNRD2上的CoAlation，补充CoA可挽救这一效应。此外，CoA代谢紊乱患者的成纤维细胞表现出线粒体脂质过氧化增加。在器官型脑片培养中，抑制CoA生物合成会导致硫氧还蛋白系统氧化、线粒体脂质过氧化以及细胞活力丧失，而铁抑素-1均可挽救这些情况。这些发现表明CoA介导的翻译后修饰调节硫氧还蛋白系统是一种替代性的铁死亡保护途径，对CoA代谢紊乱的患者具有潜在临床意义。
