METTL3/YTHDC1 axis-mediated m6A modification of Foxo1 mRNA promote endothelial autophagic apoptosis in diabetic atherosclerosis

Abstract Background and aims Endothelial dysfunction is critical in diabetic angiopathy. While our previous study established role of FOXO1 in mediating advanced glycation end products (AGEs)-induced autophagic apoptosis in human aortic endothelial cells (HAECs), the potential mechanism of N6-methyladenosine (m 6 A) modification in this process remains unknown. Methods RNA-m 6 A methylation and methyltransferase-like 3 (METTL3) / YTH domain containing 1 (YTHDC1) expression in carotid plaques of diabetic patients and aortic plaques of diabetic apoe −/− mice induced by STZ were detected by quantitative kit, immunohistochemical staining and immunofluorescence co-localization respectively. METTL3 and YTHDC1 were knocked down to observe changes in the m 6 A methylation status and expression of FOXO1. FOXO1 was overexpressed in METTL3-deficient HAECs to assess autophagic flux and apoptosis. Finally, the effect of METTL3 on atherosclerotic plaque formation was validated using endothelial cell-specific METTL3 knockout diabetic mice. Results RNA m 6 A modification levels and the expression of the METTL3/YTHDC1 were upregulated in human diabetic carotid plaques, mouse aortic plaques, and AGEs-treated HAECs, accompanied by increased m 6 A methylation of Foxo1 mRNA. METTL3 mediates the AGEs-induced increase in m 6 A modification of Foxo1 mRNA, which is subsequently recognized by the YTHDC1 at a specific site in the 3’-UTR-3. This mechanism synergistically enhances FOXO1 expression and blocks autophagic flux leading to apoptosis in endothelial cells. In vivo, endothelial-specific METTL3 knockout attenuated aortic plaque formation in diabetic atherosclerotic mice and reduced FOXO1 expression along with autophagic apoptosis related proteins. Conclusions The METTL3/YTHDC1 axis-mediated m 6 A modification of Foxo1 mRNA promotes endothelial autophagic apoptosis in diabetic atherosclerosis, revealing a promising therapeutic target.