Inhibition of p53-p21 pathway promotes the differentiation of rat bone marrow mesenchymal stem cells into cardiomyocytes

P53 is shown recently to play an important role in the proliferation and differentiation of bone marrow mesenchymal stem cells (BMMSCs). In this study, by inhibiting p53-p21 pathway with p53 inhibitor (p-fifty three inhibitor-alpha, PFT-alpha), we investigated the resulting effects on the differentiation of rat BMMSCs into cardiomyocyte-like cells. BMMSCs were isolated from bone marrow of SD rats by density gradient centrifugation. The fourth passage cells were divided into four groups: control group, PFT-alpha group, 5-AZA group, and PFT-alpha + 5-AZA group. The purified BMMSCs were identified by surface antigens and the proliferation and apoptosis of BMMSCs were examined by MTT and flow cytometry analysis. The expression of cTnI and CX-43 in BMMSCs after induction was detected by immunofluorescence and that of cTnI, p53, and p21 was detected by western blot. Our results demonstrated that PFT-alpha at 20 mu mol/l significantly reduced the apoptosis and promoted the proliferation of BMMSCs, and induced BMMSCs to differentiate into cardiomyocyte-like cells. In conclusion, these data open up new possibility of modulating p53-p21 pathway for directed differentiation of BMMSCs into cardiomyocytes, which will be valuable for cardiovascular regenerative medicine.