Graduate School of Kunming Medical University, Kunming, China.
Orthopaedics Department, 920th Hospital of Joint Logistics Support Force, Kunming, China.
Cell Biol Int. 2024 Apr;48(4):450-460. doi: 10.1002/cbin.12115. Epub 2024 Jan 2.
Osteomyelitis is a bone destructive inflammatory disease caused by infection. Ferroptosis is closely related to multiple inflammatory diseases, but the role of ferroptosis in Staphylococcus aureus (SA)-induced osteomyelitis remains unknown. In the present study, we found that SA treatment promoted the accumulation of iron, Fe , lipid peroxide, and malondialdehyde, increased TFRC and reduced FTH1 and GPX4 to trigger ferroptosis in rat bone marrow mesenchymal stem cells (BMSCs). Interestingly, increased level of N6 methyl adenosine (m6A) modification along with decreased expression level of m6A eraser FTO were observed in SA-induced BMSCs, while upregulating FTO alleviated SA-triggered ferroptosis and protected cell viability in BMSCs. Mechanistically, MDM2 was identified as a target of FTO-mediated m6A demethylation, and FTO upregulation promoted MDM2 instability to downregulated TLR4 signal and elevate the expression of SLC7A11 and GPX4 in SA-induced BMSCs. Functional recovery experiments verified that overexpressing MDM2 or TLR4 reversed the inhibiting effect of FTO upregulation on ferroptosis in SA-treated BMSCs. Additionally, FTO upregulation restrained ferroptosis and pathological damage to bone tissue in SA-induced osteomyelitis model rats. Altogether, m6A eraser FTO alleviates SA-induced ferroptosis in osteomyelitis models partly through inhibiting the MDM2-TLR4 axis.
骨髓炎是一种由感染引起的骨破坏性炎症疾病。铁死亡与多种炎症性疾病密切相关,但铁死亡在金黄色葡萄球菌(SA)诱导的骨髓炎中的作用尚不清楚。在本研究中,我们发现 SA 处理促进了铁、Fe、脂质过氧化物和丙二醛的积累,增加了 TFRC 并降低了 FTH1 和 GPX4,从而引发大鼠骨髓间充质干细胞(BMSCs)中的铁死亡。有趣的是,在 SA 诱导的 BMSCs 中观察到 N6 甲基腺苷(m6A)修饰水平增加,m6A 去甲基化酶 FTO 的表达水平降低,而上调 FTO 可减轻 SA 引发的铁死亡并保护 BMSCs 中的细胞活力。机制上,MDM2 被鉴定为 FTO 介导的 m6A 去甲基化的靶标,FTO 的上调促进了 MDM2 的不稳定性,从而下调了 TLR4 信号,并提高了 SA 诱导的 BMSCs 中 SLC7A11 和 GPX4 的表达。功能恢复实验验证了过表达 MDM2 或 TLR4 逆转了 FTO 上调对 SA 处理的 BMSCs 中铁死亡的抑制作用。此外,FTO 的上调抑制了 SA 诱导的骨髓炎模型大鼠中铁死亡和骨组织的病理损伤。总之,m6A 去甲基化酶 FTO 通过抑制 MDM2-TLR4 轴部分缓解骨髓炎模型中的 SA 诱导的铁死亡。