Abstract：
The nucleus pulposus is in a hypoxic environment in the human body, and when intervertebral disc degeneration (IVDD) occurs, the hypoxic environment is disrupted. Nucleus pulposus cell (NPC) ferroptosis is one of the causes of IVDD. N6-methyladenosine (m6A) and its reader protein YTHDF1 regulate cellular activities by affecting RNA metabolism. However, the regulation of ferroptosis in NPCs by m6A-modified RNAs under hypoxic conditions has not been as well studied. In this study, through in vitro and in vivo experiments, we explored the underlying mechanism of HIF-1α and YTHDF1 in regulating ferroptosis in NPCs. The results indicated that the overexpression of HIF-1α or YTHDF1 suppressed NPC ferroptosis; conversely, the knockdown of HIF-1α or YTHDF1 increased ferroptosis levels in NPCs. Luciferase reporter assays and chromatin immunoprecipitation demonstrated that HIF-1α regulated YTHDF1 transcription by directly binding to its promoter region. Polysome profiling results showed that YTHDF1 promoted the translation of SLC7A11 and consequently the expression of the anti-ferroptosis protein GPX4 by binding to m6A-modified SLC7A11 mRNA. In conclusion, HIF-1α-induced YTHDF1 expression reduces NPC ferroptosis and delays IVDD by promoting SLC7A11 translation in a m6A-dependent manner.
摘要：
髓核在人体内处于缺氧环境,当椎间盘退变（IVDD）发生时，缺氧环境被破坏。髓核细胞（NPC）铁性凋亡是IVDD的原因之一。N6-甲基腺苷（m6A）及其阅读器蛋白YTHDF1通过影响RNA代谢来调节细胞活性。然而,在缺氧条件下，m6A修饰的RNA对NPCs中铁凋亡的调节尚未得到很好的研究。在这项研究中,通过体外和体内实验，我们探讨了HIF-1α和YTHDF1调节NPCs铁凋亡的潜在机制。结果表明，HIF-1α或YTHDF1的过表达抑制了NPC的铁性凋亡；相反，HIF-1α或YTHDF1的敲除增加了NPCs中的铁凋亡水平。荧光素酶报告基因测定和染色质免疫沉淀表明HIF-1α通过直接结合其启动子区来调节YTHDF1的转录。多聚体谱分析结果表明，YTHDF1通过与m6A修饰的SLC7A11mRNA结合，促进了SLC7A11的翻译，从而促进了抗铁凋亡蛋白GPX4的表达。总之,HIF-1α诱导的YTHDF1表达通过以m6A依赖性方式促进SLC7A11翻译减少NPC的铁凋亡并延迟IVDD。
