Establishment of Down Syndrome Cell Lines

The cell line Ts21-ES-GATA1-WT, in which a human chromosome 21 was transferred into the human ESC line, KhES-1-derived subline, and Ts21-ES-GATA1s, in which the GATA1 mutation was introduced into the KhES-1-derived subline and then a human chromosome 21 was transferred into the GATA1s-ES, were previously established [33 (link)]. TAM-iPS-GATA1s, which was generated from the blasts of TAM patients with DS, and TAM-iPS-GATA1-WT, in which the GATA1 mutation of TAM-iPS-GATA1s was repaired, were established as described previously [36 (link)]. All PSCs were cultured on 0.25 μg/cm² Laminin511-E8 fragment iMatrix-511 silk (Nippi, Tokyo, Japan)-coated culture plates with StemFit AK02 medium (Ajinomoto, Tokyo, Japan). For passage, the cells were dissociated into single cells with 0.5×TrypLE Select (Thermo Fisher Scientific, Waltham, MA, USA) and plated at 265 cells/cm². 10 μM Rock inhibitor Y-27632 (Nacalai Tesque, Kyoto, Japan) was used at the time of the plating, and the medium was exchanged with fresh AK02 medium without Y-27632 the next day.