A) Schematic representation of the protocol. B) Morphology of colonies during the induction. Phase contrast images were taken on days 0, 3, and 7. Scale bar, 200 µm. C) The fraction of p75-positive cells in 201B7 cells was treated with SB431542 (SB) (10 µM) and CHIR99021 (CHIR) (indicated concentration) for seven days, stained with an anti-p75 antibody, and analyzed by FACS. D) Fraction of the p75high population induced by SB (10 µM) and CHIR (1 µM) from hESCs (KhES1, KhES3, H9) and hiPSCs (414C2, 201B7). Average ± SD. N = 3, biological triplicate. E) Immunocytochemical analyses of colonies on day 7 (201B7). Cells were stained with antibodies against PAX6, TFAP2A, and p75. Scale bar, 100 µm.