Induction of Neural Progenitor Cells from iPSCs

The study was approved by the Ethics Committees of the Osaka City University (approval #2472) and was conducted according to the declaration of Helsinki. In this study, we used human iPSCs derived from fetal lung fibroblast (MRC-5) cells and the iPSCs were maintained by standard culture methods as described previously (Saito et al. 2011 (link)). Neural induction was performed as described previously (Chambers et al. 2009 (link)). Briefly, neural induction will be initiated by 10 μM SB431542 (TGF-β inhibitor, Wako) and 200 ng/ml of Noggin (R&D Systems, Minneapolis, MN). After 8 days of neural induction, cells are dissociated with accutase (Chemicon, Temecula, CA) and plated onto poly-ornithine and laminin (Sigma, St. Louis, MO) with neurobasal medium supplemented with 2% B27 (Invitrogen), 20 ng/ml bFGF (Wako), 20 ng/ml epidermal growth factor (EGF, Invitrogen). Rosette neural stem cells (R-NSC) will form within a few days. R-NSCs were enriched by Neural Rosette Selection Reagent® (Stem Cell Technologies, Toronto, Canada). NPCs were obtained after a few passages and subjected to proliferation assays. Schematic diagram of induction of NPCs and representative growth rate of NPCs are shown in Additional file 1: Figure S1.