Long noncoding RNA Braveheart promotes cardiogenic differentiation of mesenchymal stem cells in vitro.

Background: Mesenchymal stem cells (MSCs) have limited potential of cardiogenic differentiation. In this study, we investigated the influence of long noncoding RNA Braveheart (lncRNA-Bvht) on cardiogenic differentiation of MSCs in vitro.
Methods: MSCs were obtained from C57BL/6 mice and cultured in vitro. Cells were divided into three groups: blank control, null vector control, and lncRNA-Bvht. All three groups experienced exposure to hypoxia (1% O ₂ ) and serum deprivation for 24 h, and 24 h of reoxygenation (20% O ₂ ). Cardiogenic differentiation was induced using 5-AZA for another 24 h. Normoxia (20% O ₂ ) was applied as a negative control during the whole process. Cardiogenic differentiation was assessed, and expressions of cardiac-specific transcription factors and epithelial-mesenchymal transition (EMT)-associated biomarkers were detected. Anti-mesoderm posterior1 (Mesp1) siRNA was transfected in order to block its expression, and relevant downstream molecules were examined.
Results: Compared with the blank control and null vector control groups, the lncRNA-Bvht group presented a higher percentage of differentiated cells of the cardiogenic phenotype in vitro both under the normal condition and after hypoxia/re-oxygenation. There was an increased level of cTnT and α-SA, and cardiac-specific transcription factors including Nkx2.5, Gata4, Gata6, and Isl-1 were significantly upregulated (P < 0.01). Expressions of EMT-associated genes including Snail, Twist and N-cadherin were much higher (P < 0.01). Mesp1 exhibited a distinct augmentation following lncRNA-Bvht transfection. Expressions of relevant cardiac-specific transcription factors and EMT-associated genes all presented a converse alteration in the condition of Mesp1 inhibition prior to lncRNA-Bvht transfection.
Conclusion: lncRNA-Bvht could efficiently promote MSCs transdifferentation into cells with the cardiogenic phenotype in vitro. It might function via enhancing the expressions of cardiac-specific transcription factors and EMT-associated genes. Mesp1 could be a pivotal intermediary in the procedure.