High Oxygen Condition Facilitates the Differentiation of Mouse and Human Pluripotent Stem Cells into Pancreatic Progenitors and Insulin-producing Cells*

Background: Oxygen plays a key role in organ development, including pancreatic -cells. Results: High oxygen conditions increase Ngn3-positive and insulin-positive cells from both mouse and human pluripotent stem cells. Conclusion: Culturing under high oxygen conditions has a facilitative effect on pancreatic differentiation. Significance: This new technique provides an efficient method to utilize patient-specific iPS cells for the treatment of diabetes. Pluripotent stem cells have potential applications in regenerative medicine for diabetes. Differentiation of stem cells into insulin-producing cells has been achieved using various protocols. However, both the efficiency of the method and potency of differentiated cells are insufficient. Oxygen tension, the partial pressure of oxygen, has been shown to regulate the embryonic development of several organs, including pancreatic -cells. In this study, we tried to establish an effective method for the differentiation of induced pluripotent stem cells (iPSCs) into insulin-producing cells by culturing under high oxygen (O-2) conditions. Treatment with a high O-2 condition in the early stage of differentiation increased insulin-positive cells at the terminus of differentiation. We found that a high O-2 condition repressed Notch-dependent gene Hes1 expression and increased Ngn3 expression at the stage of pancreatic progenitors. This effect was caused by inhibition of hypoxia-inducible factor-1 protein level. Moreover, a high O-2 condition activated Wnt signaling. Optimal stage-specific treatment with a high O-2 condition resulted in a significant increase in insulin production in both mouse embryonic stem cells and human iPSCs and yielded populations containing up to 10% C-peptide-positive cells in human iPSCs. These results suggest that culturing in a high O-2 condition at a specific stage is useful for the efficient generation of insulin-producing cells.