Miao Feifei, Luan Junjun, Feng Xiaochen, Zhang Yonghe, Feng Zixuan, Wang Zhiduo, Wang Yuqing, Yang Rong, Zhang Chen, Kopp Jeffrey B, Pi Jingbo, Zhou Hua
Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China.
Kidney Disease Section, NIDDK/NIH, Bethesda, MD, USA.
Eur J Pharmacol. 2025 Jul 15;999:177680. doi: 10.1016/j.ejphar.2025.177680. Epub 2025 Apr 24.
N6-methyladenosine (mA) plays a crucial role in kidney diseases. Methyltransferase-like 3 (METTL3) as a key mA writer can be regulated by trametinib. However, the epigenetic regulation of trametinib in focal segmental glomerulosclerosis (FSGS) remains unclear. We investigated whether trametinib protects podocytes by modulating METTL3-methylated target RNAs. Regulator of calcineurin 1 (RCAN1) was predicted as a target binding RNA of METTL3 by THEW database. Immunostaining of METTL3 and RCAN1 with podocyte marker Wilm's tumor-1 (WT-1) confirmed their localization within podocytes in renal biopsy from FSGS patients. Transfection METTL3 to human podocytes reduced WT-1, synaptopodin (SYNPO), and RCAN1 protein levels. Total mA, mA methylated RNA of RCAN1 increased and total RCAN1 mRNA decreased. Inhibition of METTL3 using siRNA or trametinib reversed these changes and attenuated the ADR-induced downregulation of WT-1 and SYNPO in vitro. In ADR-induced FSGS mice, trametinib ameliorated proteinuria, hypoalbuminemia, renal dysfunction, glomerulosclerosis and podocyte foot process effacement. Additionally, trametinib preserved podocyte function assessed by WT-1 and SYNPO as well as delayed renal fibrosis assessed by α-smooth muscle actin and fibronectin. Consistent with results in vitro, trametinib also decreased the ADR-induced upregulation of METTL3 and reversed the changed levels of total mA, mA methylated Rcan1 and total Rcan1 in FSGS mice. In conclusion, trametinib may serve as a renal protective agent for FSGS by regulating METTL3-dependent RCAN1 methylation levels.
N6-甲基腺苷（mA）在肾脏疾病中起关键作用。甲基转移酶样3（METTL3）作为关键的mA写入器可受曲美替尼调节。然而，曲美替尼在局灶节段性肾小球硬化（FSGS）中的表观遗传调控仍不清楚。我们研究了曲美替尼是否通过调节METTL3甲基化的靶RNA来保护足细胞。通过THEW数据库预测钙调神经磷酸酶调节因子1（RCAN1）是METTL3的靶结合RNA。用足细胞标志物肾母细胞瘤-1（WT-1）对METTL3和RCAN1进行免疫染色，证实它们在FSGS患者肾活检标本的足细胞内定位。将METTL3转染到人足细胞中可降低WT-1、突触素（SYNPO）和RCAN1蛋白水平。总mA、RCAN1的mA甲基化RNA增加，而总RCAN1 mRNA减少。使用小干扰RNA或曲美替尼抑制METTL3可逆转这些变化，并减轻体外阿霉素诱导的WT-1和SYNPO下调。在阿霉素诱导的FSGS小鼠中，曲美替尼改善了蛋白尿、低白蛋白血症、肾功能不全、肾小球硬化和足细胞足突消失。此外，曲美替尼保留了通过WT-1和SYNPO评估的足细胞功能，以及通过α-平滑肌肌动蛋白和纤连蛋白评估的延缓肾纤维化。与体外结果一致，曲美替尼还降低了阿霉素诱导的FSGS小鼠中METTL3的上调，并逆转了总mA、mA甲基化Rcan1和总Rcan1的变化水平。总之，曲美替尼可能通过调节METTL3依赖的RCAN1甲基化水平，作为FSGS的肾脏保护剂。
