METTL3-associated m 6 A modification of IGF2 promotes a diabetic vascular calcification phenotype in endothelial cells

Diabetic vascular calcification involves endothelial-to-mesenchymal transition (EndMT) and osteogenic differentiation; however, the underlying regulatory mechanisms remain poorly defined. This study aims to investigate the role of the RNA methyltransferase METTL3 in mediating m6A modifications that promote EndMT and osteogenic differentiation. Human aortic endothelial cells (HAECs) were exposed to high glucose (HG) and osteogenic media conditions to recapitulate diabetic vascular endothelial dysfunction and osteogenic differentiation. We investigated the mRNA and protein expression of EndMT and osteogenic markers. Loss-of- and gain-of-function studies, supplemented by rescue experiments, were used to characterize the underlying molecular mechanisms. HG-treatment increased the expression of METTL3, global m6A levels, and markers of EndMT. Under HG and osteogenic conditions, METTL3 deficiency significantly alleviated the EndMT and calcification phenotype in HAECs. Consistent with this, Western blot analysis confirmed that METTL3 promotes PI3K-Akt pathway activation, thereby driving the EndMT. We subsequently found that METTL3 and IGF2BP2 stabilize IGF2 mRNA, suggesting an m6A-dependent mechanism. This upregulation of IGF2 promotes EndMT and osteogenic differentiation by activating the PI3K-Akt pathway under diabetic osteogenic conditions. By further investigating the post-transcriptional regulation of IGF2 expression, we found that METTL3 stabilizes IGF2 mRNA through an IGF2BP2-dependent mechanism. METTL3-mediated m6A modification promotes the diabetic vascular calcification phenotype in HAECs by stabilizing IGF2 mRNA, activating the PI3K‑Akt pathway, and driving endothelial-to-osteogenic transition. Our data suggest that endothelial cells may actively participate in diabetic vascular calcification through transdifferentiation processes. These findings suggest that METTL3 may be a potential therapeutic target in diabetic vascular calcification, warranting further validation.