Direct Comparison of Distinct Cardiomyogenic Induction Methodologies in Human Cardiac-Derived c-Kit Positive Progenitor Cells

Cardiac stem/progenitor cells can be differentiated into cardiomyocytes in vitro using several differentiation methodologies. However, the methodology of cardiomyogenic induction in human c-kit positive progenitor cells (hCPCs(c-kit+)) was not fully demonstrated. Thus, the purpose of our study was to directly evaluate each cardiomyocyte induction system using hCPCs(c-kit+). In this study, cardiomyocyte induction methodologies were divided into the following three groups; treatment with dexamethasone, 5-azacytidine, and co-treatment with 5-azacytidine and Transforming Growth Factor Beta 1 (TGF-beta 1), using different serum concentrations [2% or 10% fetal bovine serum (FBS)]. GATA4 and Nkx2-5, cardiac-specific transcription factors, were expressed in our hCPCs(ckit+). However, the GATA4 and Nkx2-5 expressions were significantly decreased in 10% FBS/cardiomyogenic induction system (p < 0.01), whereas the GATA4 and Nkx2-5 expressions were preserved in 2% FBS/cardiomyogenic induction system (p > 0.05). GATA4 and Nkx2-5 is crucial roles in cardiac development, thus we considered the low serum conditions more affected in our cardiomyogenic induction system. In addition, c-kit expression decreased significantly during cardiomyogenic differentiation. Importantly, we demonstrated that co-treated with 5-azacytidine and TGF-beta 1 led to an earlier expression pattern of alpha-sarcomeric actin (alpha-SA), implying that this cardiomyocyte induction system facilitates early cardiomyocyte differentiation of hCPCs(c-kit+). Thus, the present study provides a pivotal cardiomyogenic differentiation methodology using hCPCs(c-kit+) for basic or clinical research.