Cardiomyocyte differentiation from P19 cells induced by NKX2-5.

Objective To identify the role of NKX2-5 gene in cardiomyocyte differentiation and its mechanism. Methods P19 cells were divided into transfected and non-transfected groups. In the transfected group,P19 cells were with stable expression of NKX2-5 gene. The P19 cells were cultured in suspension for 4 days,and the formed aggregates were transferred to Petri dish for adherent culture. On days 4,8,12, and 16 of the adherent culture,the expressions of α-sarcomeric actin(α-SA)and cardiac troponin T(cTnT)were detected with double-labeling immunofluorescence and Western blot. The ultrastructural changes were observed on day 16. Results In the transfected group,no expression of α-SA and cTnT was found on day 4,and the expression of these 2 proteins or co-expression existed on days 8,12,and 16. There were early cell junction and myofilament-like structure in the cytoplasm of some cells in the transfected group. In the non-transfected group,these 2 proteins were negative,and no differentiated cell was found. Conclusion Stable expression of NKX2-5 gene can induce cardiomyocyte differentiation from P19 cells,but the P19 cells with stable expression of NKX2-5 gene is not suitable to be an in vitro model of cardiac development.