Abstract 18709: MicroRNA Target Regulation is Cell Type Specific and is Influenced by Stress Conditions

MicroRNAs (miRs) modulate gene expression by repressing translation or inducing degradation of targeted mRNAs. Although miRs are currently explored as novel therapeutic targets, the cell type and context-specific effects of miRs in the heart are not well explored. Therefore, we determined target regulation using miR-92a as an example. Inhibition of miR-92a was shown to augment neovascularization and recovery after acute myocardial infarction (MI). We performed microarrays using RNA isolated from the apex of control mice (n=4), healthy mice treated with the miR-92a-inhibitior LNA-92a (2.5 mg/kg) (n=4), and mice at 4 days after MI treated with either PBS (n=4) or LNA-92a (n=3). miR-92a was inhibited by more than 95 % in all LNA-92a-treated mice. In LNA-92a treated control mice, 73 genes including only one predicted miR-92a target were significantly regulated. In mice after MI, 310 genes (fold change<+/-1.4;p<0.05) were regulated by LNA-92a including 36 predicted miR-92a targets such as cardioprotective Hmox...