Mechanical environment worsening is an important predisposing factor that accelerates intervertebral disc degeneration (IDD), but its specific regulatory mechanisms remain unclear. In this study, we reveal the molecular mechanisms of WTAP/YTHDF2-mediated m6A modification in abnormal stress-induced intervertebral disc (IVD) matrix degradation. WTAP expression in human nucleus pulposus cells was elevated under tension. Similarly, high WTAP expression was detected in severe degenerated human and rat nucleus pulposus tissues. Functionally, WTAP was found to increase the TIMP3 transcript methylation level under tension, resulting in YTHDF2 recognition, binding, and induction of its degradation. Reduction in TIMP3 caused increases in active matrix metalloproteinases, ultimately inducing extracellular matrix degradation in nucleus pulposus cells. Macroscopically, this promotes IDD. Additionally, in vitro and in vivo inhibition of WTAP expression or TIMP3 overexpression significantly increased stress resistance in the nucleus pulposus, thereby alleviating IDD. Our results show that abnormal stress disrupts IVD matrix stability through WTAP/YTHDF2-dependent TIMP3 m6A modification.

中文翻译：

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异常应激通过WTAP/YTHDF2依赖的TIMP3 m6A修饰促进椎间盘退变

机械环境恶化是加速椎间盘退变（IDD）的重要诱发因素，但其具体调控机制尚不清楚。在这项研究中，我们揭示了 WTAP/YTHDF2 介导的 m6A 修饰在异常应激诱导的椎间盘 (IVD) 基质退化中的分子机制。人髓核细胞中的 WTAP 表达在张力下升高。同样，在严重退化的人和大鼠髓核组织中检测到高 WTAP 表达。在功能上，WTAP被发现在张力下增加TIMP3转录本甲基化水平，导致YTHDF2识别、结合并诱导其降解。 TIMP3 的减少引起活性基质金属蛋白酶的增加，最终诱导髓核细胞的细胞外基质降解。从宏观上看，这促进了IDD。此外，在体外和体内抑制WTAP表达或TIMP3过表达可显着增加髓核的应激抵抗力，从而减轻IDD。我们的结果表明，异常应力通过 WTAP/YTHDF2 依赖的 TIMP3 m6A 修饰破坏 IVD 基质稳定性。