Assuntos
Diferenciação Celular , Células-Tronco Pluripotentes Induzidas/fisiologia , Miócitos Cardíacos/fisiologia , Canais de Potássio Cálcio-Ativados/fisiologia , Animais , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/metabolismo , Benzimidazóis/farmacologia , Miosinas Cardíacas/genética , Miosinas Cardíacas/metabolismo , Proliferação de Células , Forma Celular , Células Cultivadas , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Corpos Embrioides , Humanos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Canais de Potássio , Canais de Potássio Cálcio-Ativados/agonistas , Canais de Potássio Cálcio-Ativados/metabolismo , Transcrição GênicaRESUMO
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.