Zhao Yao, Li Zhaozheng, Ma Huimin, Pan Zhenwei, Cai Benzhi, Zhang Chengwei, Jiao Jundong
Department of Nephrology, The Second Affiliated Hospital of Harbin Medical University, China (Y.Z., Z.L., H.M., C.Z., J.J.).
Department of Pharmacy at The Second Affiliated Hospital, and Department of Pharmacology (The Key Laboratory of Cardiovascular Medicine Research, Ministry of Education) at College of Pharmacy (Z.P., B.C.), Harbin Medical University, China.
Arterioscler Thromb Vasc Biol. 2025 Jul;45(7):1124-1144. doi: 10.1161/ATVBAHA.124.321014. Epub 2025 May 22.
Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis in patients with end-stage renal disease, yet its long-term patency is threatened by neointimal hyperplasia (NIH). N-methyladenosine (mA), a prevalent RNA modification catalyzed by METTL3 (methyltransferase-like 3), plays a regulatory role in cardiovascular remodeling. Our previous studies found that N-methyladenosine methyltransferase METTL3 mediated cardiomyocyte proliferation and heart repair after myocardial ischemia. However, its impact on AVF-related NIH remains unclear.
We examined mA levels and METTL3 expression in human and murine AVF tissues. Using smooth muscle cell-specific METTL3 conditional knockout and METTL3-overexpressing (adeno-associated virus-METTL3) mouse models, we evaluated NIH formation. In vitro, we analyzed vascular smooth muscle cell proliferation, migration, phenotypic switching, and ferroptosis. mA epitranscriptomic microarray and RNA stability assays were used to explore downstream targets and mechanisms.
METTL3 was significantly upregulated in AVF tissues and vascular smooth muscle cells undergoing dedifferentiation. METTL3 deletion attenuated, while overexpression exacerbated, NIH in vivo. METTL3 enhanced vascular smooth muscle cell proliferation, migration, and phenotypic switching, while suppressing ferroptosis. Mechanistically, METTL3 increased mA modification of SLC7A11 (solute carrier family 7 member 11) mRNA, stabilized its transcript, and promoted translation via recruitment of the mA reader YTHDF1 (YTH [YT521-B homology domain] N6-methyladenosine RNA-binding protein 1). Silencing SLC7A11 or YTHDF1 abrogated METTL3-induced phenotypic changes and ferroptosis resistance.
The METTL3-YTHDF1-SLC7A11 axis facilitates AVF NIH by regulating vascular smooth muscle cell dedifferentiation and ferroptosis. These findings uncover a novel epitranscriptional mechanism and suggest a potential therapeutic target for AVF stenosis.
动静脉内瘘（AVF）是终末期肾病患者血液透析的首选血管通路，但其长期通畅性受到新生内膜增生（NIH）的威胁。N-甲基腺苷（mA）是一种由METTL3（甲基转移酶样3）催化的普遍存在的RNA修饰，在心血管重塑中起调节作用。我们之前的研究发现，N-甲基腺苷甲基转移酶METTL3介导心肌缺血后心肌细胞增殖和心脏修复。然而，其对AVF相关NIH的影响仍不清楚。
我们检测了人和小鼠AVF组织中的mA水平和METTL3表达。使用平滑肌细胞特异性METTL3条件性敲除和METTL3过表达（腺相关病毒-METTL3）小鼠模型，我们评估了NIH的形成。在体外，我们分析了血管平滑肌细胞的增殖、迁移、表型转换和铁死亡。使用mA表观转录组微阵列和RNA稳定性测定来探索下游靶点和机制。
METTL3在AVF组织和经历去分化的血管平滑肌细胞中显著上调。METTL3缺失减弱了体内NIH，而过表达则加剧了NIH。METTL3增强了血管平滑肌细胞的增殖、迁移和表型转换，同时抑制了铁死亡。机制上，METTL3增加了溶质载体家族7成员11（SLC7A11）mRNA的mA修饰，稳定了其转录本，并通过招募mA阅读器YTHDF1（YTH[YT521-B同源结构域]N6-甲基腺苷RNA结合蛋白1）促进翻译。沉默SLC7A11或YTHDF1消除了METTL3诱导的表型变化和铁死亡抗性。
METTL3-YTHDF1-SLC7A11轴通过调节血管平滑肌细胞去分化和铁死亡促进AVF NIH。这些发现揭示了一种新的表观转录机制，并提示了AVF狭窄的潜在治疗靶点。
