METTL3 and type 2 diabetes mellitus: Previous studies have shown that METTL3 was elevated in peripheral venous blood and livers of T2D patients [26], [34], while the reason for METTL3 increase was considered as a result of FTO-induced decrease in m6A. High-glucose stimulation elevated FTO expression, which led m6A to decrease, as a response, METTL3 might increase to maintain the normal m6A level [34].