β-Catenin stabilization promotes proliferation and increase in cardiomyocyte number in chick embryonic epicardial explant culture.

Cardiomyocyte (CM) differentiation from proepicardial organ- (PEO) and embryonic epicardium (eEpi)-derived cells or EPDCs in a developing heart emerges as a wide interest in purview of cardiac repair and regenerative medicine. eEpi originates from the precursor PEO and EPDCs, which contribute to several cardiac cell types including smooth muscle cells, fibroblasts, endothelial cells, and CMs during cardiogenesis. Here in this report, we have analyzed several cardiac lineage-specific marker gene expressions between PEO and eEpi cells. We have found that PEO-derived cells show increased level of CM lineage-specific marker gene expression compared to eEpi cells. Moreover, Wnt signaling activation results in increased level of CM-specific marker gene expression in both PEO and eEpi cells in culture. Interestingly, Wnt signaling activation also increases the number of proliferating and sarcomeric myosin (Mf20)-positive cells in eEpi explant culture. Together, this data suggests that eEpi cells as a source for CM differentiation and Wnt signaling mediator, β-catenin, might play an important role in CM differentiation from eEpi cells in culture.