MicroRNA-10-5p regulates differentiation of bone marrow mesenchymal stem cells into cardiomyocytes by targeting TBX5.

OBJECTIVE: The purpose of the study was to investigate the regulatory effect of microRNA-10-5p on TBX5 during myocardial differentiation of bone marrow mesenchymal stem cells (BMSCs) in rats.

MATERIALS AND METHODS: Rat BMSCs were first isolated, cultured and identified by flow cytometry. Expression levels of BNP (Brain Natriuretic Peptide), α-actinin, and Islet-1 in BMSCs co-cultured with rat cardiomyocytes were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Dual-luciferase reporter gene assay was conducted to verify the binding condition between microRNA-10-5p and TBX5. Subsequently, we detected TBX5 expression after overexpression or knockdown of microRNA-10-5p in BMSCs. Rescue experiments were conducted by overexpression of both microRNA-10-5p and TBX5 in BMSCs, and then, the expression levels of BNP, α-actinin, and Islet-1 were detected by qRT-PCR and Western blot.

RESULTS: Flow cytometry results showed positive-CD73 (99.3%), positive-CD90 (95.4%), and negative-CD34 (4.2%), which were consistent with immunophenotypic characteristics of BMSCs. TBX5 overexpression or microRNA-10-5p knockdown increased mRNA levels of BNP, α-actinin, and Islet-1 in BMSCs co-cultured with rat cardiomyocytes. Dual-luciferase reporter gene assay confirmed that microRNA-10-5p could bind to TBX5. Both mRNA and protein expressions of TBX5 were negatively regulated by microRNA-10-5p. The inhibited expression levels of BNP, α-actinin, and Islet-1 by microRNA-10-5p overexpression in BMSCs were partially reversed by TBX5 overexpression.

CONCLUSIONS: MicroRNA-10-5p regulates BMSCs differentiation into cardiomyocytes by binding to TBX5.