Suppression of MicroRNA-203 improves survival of rat bone marrow mesenchymal stem cells through enhancing PI3K-induced cellular activation.

As a group of heterogeneous multipotent cells, mesenchymal stem cells (MSCs) have potential in treatment of a variety of clinical diseases. However, the low survival of the transplanted MSCs reduced their therapeutic effects. In this study, we revealed that rno-miR-203 suppressed activity and colony formation and enhanced apoptosis of the rat bone marrow-derived MSCs (BM-MSCs). Using bioinformatics analysis, we found a potential miR-203 binding site within rat phosphatidylinositol 3-kinase (PI3K) 3'UTR, and fluorescent reporter experiments validated the direct and negative regulation of PI3K expression by miR-203 through this site. Ectopic expression of PI3K rescued BM-MSCs from depressed activity induced by miR-203, and suppression of PI3K attenuated the increased BM-MSCs activity by miR-203 inhibitor treatment. Moreover, miR-203 blocking partly protected BM-MSCs from impairment caused by low nutrition. We conclude that inhibition of endogenous miR-203 elevated PI3K expression, which may strengthen PI3K/Akt pathway and promote BM-MSCs activity and survival.