Upregulation of lncRNA RMRP promotes the activation of cardiac fibroblasts by regulating miR-613

Long non-coding RNAs (lncRNAs) have been reported to serve a key role in a variety of cardiovascular diseases, including in cardiac fibrosis. The present study aimed to investigate the biological role and underlying mechanisms of the induction of cardiac fibroblasts by the lncRNA, RNA component of mitochondrial RNA processing endoribonuclease (RMRP). The results demonstrated that RMRP expression was upregulated in the presence of cardiac fibrosis in an abdominal aortic banding-treated rat model. Treatment with angiotensin II increased RMRP expression in cardiac fibroblasts, while the knockdown of RMRP by small-interfering RNA inhibited cardiac fibroblast proliferation, differentiation and collagen accumulation. To further investigate the underlying mechanisms of this interaction, microRNA (miR)-613 was predicted to be a target miR of RMRP and sequence alignment, luciferase activity and MS2 RNA immunoprecipitation were performed to detect the interaction between RMRP and miR-613. The results suggested that RMRP negatively regulated miR-613 in cardiac fibroblasts. Furthermore, miR-613 was indicated to mediate the promoting effect of RMRP on cardiac fibroblast activation. The current study suggested that RMRP promoted cardiac fibroblast activation by acting as a competing endogenous RNA for miR-613. Therefore, RMRP may be a novel target for the prevention or treatment of cardiac fibrosis.