For SFEBq culture, hESCs were dissociated to single cells in TrypLE Express (Invitrogen) containing 0.05 mg ml
−1 DNase I (Roche) and 10 μM Y-27632 (TOCRIS), and quickly reaggregated using low-cell-adhesion 96-well plates with V-bottomed conical wells (Sumilon PrimeSurface plate; Sumitomo Bakelite) in differentiation medium (9,000 cells per well, 100 μl) containing 20 μM Y-27632 under 5% CO
2. The differentiation medium was Glasgow-MEM (Invitrogen) supplemented with 20% (vol/vol) KSR, 0.1 mM nonessential amino acids, 1 mM pyruvate, 0.1 mM 2-mercaptoethanol, 100 U ml
−1 penicillin and 100 μg ml
−1 streptomycin. Defining the day on which the SFEBq culture was started as day 0, 3 μM IWR1e (Wnt inhibitor; Calbiochem) and 5 μM SB431542 (TGFβ inhibitor; TOCRIS) were added to culture from day 0 to day 18. The culture method after day 18 was as follows.
For neocortical induction (condition 1,
Fig. 1)12 (
link), at day 18, the floating aggregates were transferred from a 96-well plate to a 9-cm Petri dish (non-cell adhesive) and further cultured in suspension using DMEM/F-12, GlutaMAX(TM) (Gibco) medium supplemented with 1% N-2 supplement (Invitrogen), 1% Chemically Defined Lipid Concentrate (Invitrogen), 0.25 mg ml
−1 fungizone (Gibco), 100 U ml
−1 penicillin and 100 μg ml
−1 streptomycin under 40% O
2/5% CO
2 conditions.
For choroid plexus-like tissue generation (condition 2,
Fig. 1), from day 18, the floating aggregates were transferred to a Petri dish (non
-cell adhesive) and further cultured in suspension using DMEM/F-12 GlutaMAX(TM) (Gibco) supplemented with 1% N-2 supplement (Invitrogen), 1% Chemically Defined Lipid Concentrate (Invitrogen), fetal bovine serum (FBS; 10% vol/vol), 3 μM CHIR 99021 (GSK3 inhibitor; Stemgent) and 0.5 nM BMP4 (R&D) under 40% O
2/5% CO
2 conditions. Medium was changed once every 3 days.
For medial pallium induction (condition 3,
Fig. 2), the culture condition from day 0 to day 21 was the same as the choroid plexus induction condition. On day 21, the medium was changed to DMEM/F-12 GlutaMAX(TM) supplemented with 1% N-2 supplement, 1% Chemically Defined Lipid Concentrate, and FBS (10% vol/vol). Medium was changed once every 3 days.
For long-term culture of medial pallium tissues, the aggregates were cultured under the following conditions. On day 27, the base medium was changed to Neurobasal medium (Gibco) supplemented with 2% B-27 supplement without vitamine A (Gibco), 2 mM
L-glutamine, 100 U ml
−1 penicillin, 100 μg ml
−1 streptomycin, 0.25 mg ml
−1 fungizone (Gibco) and FBS (10% vol/vol). At day 35, the aggregates were cut into half-size with fine forceps under a dissecting microscope for the prevention of cell death in the central portions, and were cultured using a Lumox dish (SARSTEDT; high-O
2 penetration) after day 50. Medium change was performed once every 3 days.
Sakaguchi H., Kadoshima T., Soen M., Narii N., Ishida Y., Ohgushi M., Takahashi J., Eiraku M, & Sasai Y. (2015). Generation of functional hippocampal neurons from self-organizing human embryonic stem cell-derived dorsomedial telencephalic tissue. Nature Communications, 6, 8896.