Role of alpha‐ and beta‐adrenergic receptors in cardiomyocyte differentiation from murine‐induced pluripotent stem cells

Objectives Induced pluripotent stem cell ( iPSC )‐derived cardiomyocytes are a promising source of cells for regenerative heart disease therapies, but progress towards their use has been limited by their low differentiation efficiency and high cellular heterogeneity. Previous studies have demonstrated expression of adrenergic receptors ( AR s) in stem cells after differentiation; however, roles of AR s in fate specification of stem cells, particularly in cardiomyocyte differentiation and development, have not been characterized. Materials and methods Murine‐induced pluripotent stem cells (mi PSC s) were cultured in hanging drops to form embryoid bodies, cells of which were then differentiated into cardiomyocytes. To determine whether AR s regulated mi PSC differentiation into cardiac lineages, effects of the AR agonist, epinephrine ( EPI ), on mi PSC differentiation and underlying signalling mechanisms, were evaluated. Results Treatment with EPI , robustly enhanced mi PSC cardiac differentiation, as indicated by increased expression levels of cardiac‐specific markers, GATA 4 , Nkx2.5 and Tnnt2 . Although β‐ AR signalling is the foremost signalling pathway in cardiomyocytes, EPI ‐enhanced cardiac differentiation depended more on α‐ AR signalling than β‐ AR signalling. In addition, selective activation of α 1 ‐ AR signalling with specific agonists induced vigorous cardiomyocyte differentiation, whereas selective activation of α 2 ‐ or β‐ AR signalling induced no or less differentiation, respectively. EPI ‐ and α 1 ‐ AR ‐dependent cardiomyocyte differentiation from mi PSC s occurred through specific promotion of CPC proliferation via the MEK ‐ ERK 1/2 pathway and regulation of mi PS cell‐cycle progression. Conclusions These results demonstrate that activation of AR s, particularly of α 1 ‐ AR s, promoted mi PSC differentiation into cardiac lineages via MEK ‐ ERK 1/2 signalling .