Hyperpolarization Induces Differentiation in Human Cardiomyocyte Progenitor Cells
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In the past years, cardiovascular progenitor cells have been isolated from the human heart and characterized. These cells can differentiate into cardiomyocytes, smooth muscle cells and endothelial cells and are therefore of great value for investigation of the mechanisms that drive progenitor cell function and plasticity, drug testing and, potentially, therapeutical purposes. In this respect, most studies have focused on enhancing differentiation with chemicals or growth factors, or co-culture with other cell types. Although they have revealed important mechanisms, protocols need to be established that exclude the need for such factors when one considers using progenitor cells to repair the human heart. In this study we tested whether we could induce cardiomyogenic differentiation of human cardiomyocyte progenitor cells (CMPCs) by altering their membrane potential. We induced hyperpolarization in CMPCs by either co-culturing them with a Kir2.1-overexpressing cell line or by overnight culture in medium containing low potassium concentrations. Hyperpolarization led to increased intracellular calcium concentrations, activation of calcineurin signaling, increased cardiac-specific gene and protein expression levels and, ultimately, to the formation of spontaneously beating cardiomyocytes. Thus, hyperpolarization is sufficient to induce differentiation of CMPCs, thereby revealing a novel mechanism for cardiomyogenic differentiation of heart-derived progenitor cells.
KeywordsProgenitor cell Cardiomyocyte Differentiation Membrane potential Electrophysiology Biophysical signaling Calcineurin
cardiomyocyte progenitor cell
- ES cell
embryonic stem cell
inward rectifier current
potassium inward rectifier
- KWGF cell
HEK 293 cell stably expressing murine wild-type Kir2.1-GFP fusion protein
nuclear factor of activated T-cells
regulator of calcineurin 1
resting membrane potential
transforming growth factor beta
We are very grateful to Corina Metz, Tom Korfage, Pieter Glerum and Lukas Nalos for technical assistance and Dr. Marta Roccio for valuable comments. We want to thank Dr. Leon de Windt for helpful discussions and for providing us with the adenovirus. This work was supported by a VIDI grant (016.056.319) from the Netherlands Organization for Scientific Research (NWO), the Van Ruyven foundation, the BSIK program “Dutch Program for Tissue Engineering” and the Netherlands Heart Foundation (2003B073 and 2005T102).
Conflict of Interest
The authors declare no potential conflicts of interest.
Spontaneous beating clusters of CMPC-derived cardiomyocytes 5 weeks after induction of differentiation by hyperpolarization. (MPG 9004 kb)
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