Inhibition of Notch signaling improves the efficiency of MK production most effectively from day 5. (A) Representative FACS analysis of the percentage of HSPCs (CD34⁺CD45⁺), MKPs (CD34⁺CD41⁺), and MKs (CD41⁺CD42⁺) on day 14 in hematopoietic cells derived from BC1 iPSCs, with addition of 10 μM GSIs (RO4929097 or DAPT) or DMSO (control) from day 5. (B) Bar graph depicting fold changes in the cell numbers of HSPCs, MKPs, and MKs on day 14 in hematopoietic cells derived from BC1 iPSCs, with addition of 10 μM GSIs (RO4929097 or DAPT) or DMSO (control) from day 5. Data are shown as the means ± SEM, n = 3. *P < .05; **P < .01; ***P < .001. (C) The number of CFU-MK colonies from 10 000 hematopoietic cells on day 14 derived from BC1 iPSCs, with addition of 10 μM GSIs (RO4929097 or DAPT) or DMSO (control) from day 5. Data are shown as the means ± SEM, n = 3. *P < .05. (D) RT-qPCR analysis of NOTCH1-4 at days 0, 2, 5, 8, 11, and 14 during differentiation from BC1 iPSCs. Data from 1 representative experiment are shown. β-Actin was used as an internal control. Results from day 0 EBs were set to 1. Data are shown as the means ± SEM, n = 3.