Stagewise keratinocyte differentiation from human embryonic stem cells by defined signal transduction modulators

we use human embryonic stem cells to demonstrate that epidermal ectoderm and subsequent keratinocyte cell fate can be determined step by step under the regulation of defined factors. We show the global gene expression profiles clustered according to the differentiation stages . We also found the human keratinocyte specific gene expression according to the differentiation stages. Total RNA obtained from Day 0 to Day 8, cells were cultured in differentiation medium with the following treatments: Day 0-6, 10 µM SB431542; Day 1-6, 5 µM CHIR99021; Day 1-8, 10 ng/ml BMP4 (R&D 314-BP-01M); Day 4-8, 5 µM DAPT (Tocris 2634). From Day 9 to Day 11, the medium was changed to low-calcium differentiation medium (containing 0.06 mM calcium) supplemented with BMP4/DAPT/EGF (10 ng/ml). Day 11 to Day 26, the cells in low calcium keratinocyte medium.