(2 μg/ml; Sigma Aldrich), Laminin (1 μg/ml; Life Technologies), dibutyryl cAMP (500 μg/ml; Sigma Aldrich), human recombinant Noggin (150 ng/ml; Preprotech), LDN-193189 (0.5 μM; Cayman Chemicals) and A83-1 (0.5 μM; Stemgent), CHIR99021 (3 μM; LC Laboratories), Forskolin (5 μM; LC Laboratories), and SB-431542 (10 μM; Cayman Chemicals). Medium was changed every third day. For further maturation, iNs were switched to DMEM:F12/Neurobasal-based neural maturation media (NM) containing N2, B27, GDNF, BDNF (both 20 ng/ml; R&D), dibutyryl cAMP (500 μg/ml; Sigma Aldrich), doxycycline (2 μg/ml; Sigma-Aldrich), and laminin (1 μg/ml; Life Technologies). For maturation on astrocyes, iNs were dislodged during week 4 using TrypLE and replated on a feeder layer of mouse astrocytes and cultured in NM media containing 1% knockout serum replacement (KOSR) (Life Technologies).
