Modulation of calcium activated potassium channels induces cardiogenesis of pluripotent stem cells and enrichment of pacemaker- like cells

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 Ca2+-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 towards the cardiac lineage. Methods and Results: We have applied the SKCa-activator EBIO 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 EBIO-induced effects.

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Kleger A, Seufferlein T, Malan D, Tischendorf M, Storch A, Wolheim A, Latz S, Protze S, Porzner M, Proepper C, Brunner C, Katz SF, Varma Pusapati G, Bullinger L, Franz WM, Koehntop R, Giehl K, Spyrantis A, Wittekindt O, Lin Q, Zenke M, Fleischmann BK, Wartenberg M, Wobus AM, Boeckers TM, Liebau S