TGF-β1 enhanced myocardial differentiation through inhibition of the Wnt/β-catenin pathway with rat BMSCs

Objective(s): To investigate and test the hypotheses that TGF-I²1 enhanced myocardial differentiation through Wnt/I²-catenin pathway with rat bone marrow mesenchymal stem cells (BMSCs).Materials and Methods: Lentiviral vectors carrying the TGF-I²1 gene were transduced into rat BMSCs firstly. Then several kinds of experimental methods were used to elucidate the related mechanisms by which TGF-I²1 adjusts myocardial differentiation in rat BMSCs. Results: Immunocytochemistry revealed that cTnI and Cx43 expressed positively in the cells that were transduced with TGF-I²1. The results of Western blot (WB) test showed that the levels of intranuclear I²-catenin and total I²-catenin were all significantly decreased. However, the cytoplasmic I²-catenin level was largely unchanged. Moreover, the levels of GSK-3I² were largely unchanged in BMSCs, whereas phosphorylated GSK-3I² was significantly decreased in BMSCs. When given the activator of Wnt/I²-catenin pathway (lithium chloride, LiCl) to BMSCs transducted with TGF-I²1, I²-catenin was increased, while phosphorylated I²-catenin was decreased. In addition, cyclinD1, MMP-7, and c-Myc protein in BMSCs transducted with Lenti-TGF-I²1-GFP were significantly lower. Conclusion: These results indicate that TGF-I²1 promotes BMSCs cardiomyogenic differentiation by promoting the phosphorylation of I²-catenin and inhibiting cyclinD1, MMP-7, and c-Myc expression in Wnt/I²-catenin signaling pathway.