Culture of Human Embryonic Stem Cells using Sodium Butyrate (NaB), a Histone Deacetylase Inhibitor

Human embryonic stem cells (hESCs) are mostly derived from the inner cell mass of the blastocyst and possess the ability to self-renew and differentiate into all the cells composing our body. These properties make hESCs a promising cell source for future cell replacement therapy. In order to use hESCs for clinical purposes, several issues have to be resolved such as avoidance of the xenogen contamination, prevention of tumor formation and efficient differentiation of the hESCs into a specific cell type of interest. Conventionally, hESCs has been cultured on mouse embryonic fibroblast (MEF) feeder cells in the medium containing knockout serum replacer (KSR) and basic fibroblast growth factor (bFGF). Several efforts have been made to develop more efficient media that could support undifferentiated growth of hESCs. Most of these developments have been taking advantage of the signaling pathways critically involved in self-renewal of hESCs. In this study, we tried to evaluate a method to culture hESCs by regulating epigenetic status using a histone deacetylase inhibitor, sodium butyrate (NaB). In our study, 0.2 mM of NaB could efficiently support undifferentiated growth of hESCs more than 20 passages. The hESCs cultured in the NaB-based medium were shown to express typical undifferentiated markers when analyzed by immunostaining and RT-PCR experiments. Finally, hESCs maintained for more than 20 passages displayed normal karyotype. Cumulatively, our results indicate that epigenetic regulators such as NaB could be used to culture hESCs by replacing otherwise essential growth factors such as bFGF. This study would provide useful information which might be translated into culturing hESCs for future clinical applications.