Abstract 15738: Electrical Stimulation Enhances Efficiency of Cardiac Differentiation of Human Induced Pluripotent Stem Cells by Regulating P38 Map Kinase
Background: Induced pluripotent stem cells (iPSC) can efficiently differentiate into functional cardiomyocytes through embryoid body (EB) differentiation in the presence of specific differentiation signals (e.g. TGF-β, Wnts). Recent studies have indicated that electrical stimulation (EleS) can enhance proliferation and differentiation efficacy in various stem cells. This study investigated the effects of EleS on human iPSC differentiation into cardiomyocytes and explored the underlying mechanisms.
Methods and Results: The classical hanging-drop method was used to induce EB formation from human iPSCs. EBs were then treated with or without EleS (1-1.5 V/1.8 cm with 5ms biphasic square wave pulses at 5 Hz) for 1 to 30 days. The percentage of contracting EBs as well as contraction rate was examined. EBs started to beat at 2 days after EleS while spontaneous beating cells without EleS appeared at 7 days. In addition, the percentage of contracting cardiac progenitor cells (CPCs) and contraction rate were significantly higher in EleS group than unpaced group. Beating CPCs were also confirmed using the genetically encoded calcium indicator, GCaMP5 driven by troponin T gene promoter, which consists of a Ca2+-sensitive calmodulin domain fused to GFP. Furthermore, expression of cardiac differentiation markers such as α-sarcomeric actinin, cTnT, αMHC, GATA4 and NKX2.5 were markedly increased by EleS as compared to non-EleS, as determined by immunocytochemical analysis and real time PCR. p38 MAP kinase signaling was identified as one of the key regulators by which EleS accelerates cardiac differentiation.
Conclusion: EleS enhances efficiency of cardiac differentiation in iPSCs by increasing p38 MAP kinase signaling, which is a novel promising approach for clinical application of iPSCs.
Author Disclosures: R. Ma: None. L. Guo: None. L. Wang: None. H. Kondo: None. R. Millard: None. H. Kim: None. Y. Wang: None.
- © 2014 by American Heart Association, Inc.