MicroRNA-1 Regulates Cardiomyocyte Apoptosis by Targeting Bd-2

MicroRNA-1 (miR-1) is preferentially expressed in cardiac muscles, and the expression has been demonstrated to be involved in cardiac development and cardiovascular diseases. Here we report that miR-1 is closely related with ischemia/perperfusion injury in a rat model. The level of miR-1 is inversely correlated with Bcl-2 protein expression in cardiomyocytes of the I/R rat model. In vitro, the level of miR-1 was dramatically increased in response to H2O2. Overexpression of miR-1 facilitated H2O2-induced apoptosis in cardiomyocytes. Inhibition of miR-1 by antisense inhibitory oligonucleotides caused marked resistance to H2O2. Through bioinformatics, we identified the potential target sites for miR-1 on the 3' UTR of Bcl-2. miR-1 significantly reduced the expression of Bcl-2 in the levels of miRNA and protein. The post-transcriptional repression of Bcl-2 was further confirmed by luciferase reporter experiments. These data demonstrated that miR-1 plays an important role in the regulation of cardiomyocyte apoptosis, which is involved in post-transcriptional repression of Bcl-2. (Int Heart J 2009 50: 377-387)