Peking University Research Center on Aging, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, 100191, Beijing, China.
Department of Orthodontics, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, 100081, Beijing, China.
Cell Death Differ. 2021 May;28(5):1593-1609. doi: 10.1038/s41418-020-00689-5. Epub 2020 Dec 7.
Despite the emerging evidence on ferroptosis implicated in diverse pathologies, molecular linkage between oxidative inducers and chromatin as epigenetic memory carrier for its propagation remains elusive. Here, we report the identification of two WD40 proteins DCAF8 and WDR76 as substrate adapter and molecular inhibitor respectively of the Cullin-4 RING ubiquitin ligase (CRL4) system for stability control of chromatin remodeler LSH. Degradation analysis and CRL4-DCAF8 complex reconstitution demonstrate that CRL4 is a bona fide E3 ligase for LSH. In contrast, WDR76 antagonizes DCAF8-targeted LSH proteolysis through competitive inhibition of the holo-CRL4-LSH complex assembly. Importantly, this opposing regulatory strategy is utilized in lipid hydroperoxide induced ferroptosis, where we identify key redox homeostasis genes significantly regulated by the DCAF8/WDR76/LSH axis through transcriptomic epistasis analysis. This regulation is mechanistically attributed to DNA hydroxymethylation fostered WDR76 interaction with LSH and increased ratio of DCAF8 to WDR76 for antagonistic LSH association accompanying decreased DNA oxidation along with ROS overproduction. Evaluation of epigenetic dynamics at ferroptosis gene promoters reveals linker histone H1- and LSH-associated transcriptional repression is coordinately removed upon lipid peroxidation stress. Together with the phenotypes driven by WDR76 and DCAF8 manipulations, these data identify DCAF8- and WDR76-adapted oxidative damage sensing through DNA hydroxymethylation for LSH degradation control as a crucial nexus in epigenetic regulation of ferroptosis.
尽管铁死亡在多种疾病中的作用证据不断涌现，但氧化诱导剂与染色质之间的分子联系作为其传播的表观遗传记忆载体仍然难以捉摸。在这里，我们报告了两种 WD40 蛋白 DCAF8 和 WDR76 的鉴定，它们分别作为 Cullin-4 RING 泛素连接酶（CRL4）系统的底物衔接子和分子抑制剂，用于染色质重塑因子 LSH 的稳定性控制。降解分析和 CRL4-DCAF8 复合物重建表明，CRL4 是 LSH 的真正 E3 连接酶。相比之下，WDR76 通过竞争性抑制全 CRL4-LSH 复合物组装来拮抗 DCAF8 靶向的 LSH 蛋白水解。重要的是，这种相反的调节策略被用于脂质氢过氧化物诱导的铁死亡中，我们通过转录组上位性分析确定了关键的氧化还原稳态基因受到 DCAF8/WDR76/LSH 轴的显著调节。这种调节机制归因于 DNA 羟甲基化促进了 WDR76 与 LSH 的相互作用，并增加了 DCAF8 与 WDR76 的比值，从而拮抗 LSH 结合，同时伴随着 DNA 氧化减少和 ROS 过度产生。对铁死亡基因启动子的表观遗传动态的评估表明，组蛋白 H1 和 LSH 相关的转录抑制在脂质过氧化应激时被协同去除。结合由 WDR76 和 DCAF8 操作驱动的表型，这些数据确定了 DCAF8 和 WDR76 适应的氧化损伤感应通过 DNA 羟甲基化进行，用于 LSH 降解控制，作为铁死亡表观遗传调节的关键枢纽。
