Human gingival fibroblast feeder cells promote maturation of induced pluripotent stem cells into cardiomyocytes

The use of human induced pluripotent stem (iPS) cells has been investigated in multiple regenerative medicine studies. However, although methods for efficient differentiation of iPS cells into heart tissues have been devised, it remains difficult to obtain cardiac tissue with high contractility. Herein, we established a method for differentiating iPS cells into highly contractile cardiomyocytes (CMs), and demonstrate that the use of human gingival fibroblasts (HGFs) as a feeder cells promotes maturation of iPS-derived CMs (iPS-CMs) in vitro. After CM differentiation of iPS cells, iPS-CMs showed increased mRNA expression of the CM specific maker cardiac troponin T (cTnT) in the absence and presence (on-feeder condition) of cocultured HGFs, and decreased expression of pluripotent markers was observed under both conditions. Protein expression of cTnT was also observed in immunocytochemical analyses, although on-feeder CMs showed comparatively robust sarcomere structure and significantly stronger contractility than feederless cardiomyocytes, suggesting that HGF feeder cells facilitate CM differentiation of iPS cells.