Enhanced Pluripotent Cell Function through miR-203-mediated Control of DNA Methylation

Maintaining a full differentiation potential along self-renewal ability is a major property of stem cells during development and regeneration. miR-203 is a microRNA previously involved in skin differentiation and tumor suppression. We show here that transient expression of miR-203 enhances the potential of embryonic (ESC) and induced pluripotent stem cells (iPSC) in contributing to multiple lineages without decreasing their self-renewal properties. In fact, miR-203 significantly improves the efficiency of ES/iPS cells in the generation of quimeras and tetraploid complementation assays, in addition to improving the generation of complex teratomas and embryo-like structures in vivo. These effects are mediated by the direct miR-203-dependent repression of de novo DNA methyltransferases Dnmt3a and Dnmt3b, leading to genome-wide demethylation of pluripotent cells. Transient exposure to miR-203 improves functional differentiation and maturation of pluripotent cells into cardiomyocytes in a Dnmt3a/b-dependent manner, suggesting the possible therapeutic uses of this microRNA in regenerative medicine.