hiPSCs were derived as described previously (http://www.nature.com/articles/npjschz201519); replicating but nearly confluent HFs were transfected with Cytotune Sendai virus (Life Technologies). Cells were allowed to recover for at least 3 days, dissociated with TrypleE (Life Technologies) and re-plated onto a 10-cm dish containing 1 million mouse embryonic fibroblasts (mEFs). Cells were switched to HUES media (DMEM/F12 (Invitrogen), 20% KO-Serum Replacement (Invitrogen), 1× Glutamax (Invitrogen), 1× NEAA (Invitrogen), 1× 2-mercaptoethanol (Sigma) and 20 ng/ml FGF2 (Invitrogen)) and fed every 2–3 days. hiPSC colonies were manually picked and clonally plated onto 24-well mEF plates in HUES media. At early passages, hiPSCs were split through manual passaging, but at higher passages, hiPSC could be enzymatically passaged with Collagenase (1mg/ml in DMEM) (Sigma). Karyotyping analysis was performed by Wicell Cytogenetics (Madison WI); only karyotypically normal lines were used for subsequent studies.
