METTL3 and diabetes mellitus: The PTEN/Akt axis has been reported to be closely related with the development of diabetes mellitus [25, 26] and was the downstream target of miR-25-3p in high-glucose treated renal tubular epithelial cells [31], which enlightened us that high-glucose might regulate PTEN/Akt axis through METTL3 and miR-25-3p in RPE cells.