Asunto(s)
Diferenciación Celular , Células Madre Pluripotentes Inducidas/fisiología , Miocitos Cardíacos/fisiología , Canales de Potasio Calcio-Activados/fisiología , Animales , Antígenos de Diferenciación/genética , Antígenos de Diferenciación/metabolismo , Bencimidazoles/farmacología , Miosinas Cardíacas/genética , Miosinas Cardíacas/metabolismo , Proliferación Celular , Forma de la Célula , Células Cultivadas , Canales Catiónicos Regulados por Nucleótidos Cíclicos/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/metabolismo , Cuerpos Embrioides , Humanos , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización , Células Madre Pluripotentes Inducidas/metabolismo , Ratones , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Contracción Miocárdica , Miocitos Cardíacos/metabolismo , Cadenas Pesadas de Miosina/genética , Cadenas Pesadas de Miosina/metabolismo , Canales de Potasio , Canales de Potasio Calcio-Activados/agonistas , Canales de Potasio Calcio-Activados/metabolismo , Transcripción GenéticaRESUMEN
BACKGROUND: Ion channels are key determinants for the function of excitable cells, but little is known about their role and involvement during cardiac development. Earlier work identified Ca(2+)-activated potassium channels of small and intermediate conductance (SKCas) as important regulators of neural stem cell fate. Here we have investigated their impact on the differentiation of pluripotent cells toward the cardiac lineage. METHODS AND RESULTS: We have applied the SKCa activator 1-ethyl-2-benzimidazolinone on embryonic stem cells and identified this particular ion channel family as a new critical target involved in the generation of cardiac pacemaker-like cells: SKCa activation led to rapid remodeling of the actin cytoskeleton, inhibition of proliferation, induction of differentiation, and diminished teratoma formation. Time-restricted SKCa activation induced cardiac mesoderm and commitment to the cardiac lineage as shown by gene regulation, protein, and functional electrophysiological studies. In addition, the differentiation into cardiomyocytes was modulated in a qualitative fashion, resulting in a strong enrichment of pacemaker-like cells. This was accompanied by induction of the sino-atrial gene program and in parallel by a loss of the chamber-specific myocardium. In addition, SKCa activity induced activation of the Ras-Mek-Erk signaling cascade, a signaling pathway involved in the 1-ethyl-2-benzimidazolinone-induced effects. CONCLUSIONS: SKCa activation drives the fate of pluripotent cells toward mesoderm commitment and cardiomyocyte specification, preferentially into nodal-like cardiomyocytes. This provides a novel strategy for the enrichment of cardiomyocytes and in particular, the generation of a specific subtype of cardiomyocytes, pacemaker-like cells, without genetic modification.