MicroRNA-133a regulates DNA methylation in diabetic cardiomyocytes

► We propose that miR-133a acts as an epi-miRNA. ► miR-133a regulates both maintenance and de novo methylation. ► miR-133a ameliorates glucose mediated induction of Dnmt-1. ► Acute and chronic hyperglycemia trigger different Dnmt's. ► Dnmt's have unique cross talk in Ins2+/− diabetic hearts.