Improved efficiency of definitive endoderm induction from human induced pluripotent stem cells in feeder and serum-free culture system.

Improvement of methods to produce endoderm-derived cells from pluripotent stem cells is important to realize high-efficient induction of endodermal tissues such as pancreas and hepatocyte. Difficulties hampering such efforts include the low efficiency of definitive endoderm cell induction and establishing appropriate defined culture conditions to ensure a safe cell source for human transplantation. Based on previous studies, we revised the experimental condition of definitive endoderm induction in feeder- and serum-free culture. Our results suggested that CHIR99021 is more effective than Wnt3A ligand in feeder- and serum-free conditions. In addition, keeping cell density low during endoderm induction is important for the efficiency. On the other hand, we showed that overtreatment with CHIR99021 converted the cells into BRACHYURY-expressing posterior mesoderm cells rather than endoderm, indicating strict CHIR99021 treatment requirements for endoderm differentiation. Nevertheless, these results should enable better control in the production of definitive endoderm-derived cells.