Ngn2-iN cells were generated as described13. To generate AMD- and AD-iN cells, ES or iPS cells were treated with Accutase (Innovative Cell Technologies) and plated as dissociated cells in six-well plates (H1 cells: ~5 × 104 cells/well; iPS cells: 7.5 × 104 cells/well) on day −2. Cells were plated on plates coated with matrigel (BD Biosciences) mTeSR1 containing 2 μM thiazovivin (Bio Vision). On day −1, lentivirus prepared as described above (1.5 μl/well of six-well plate) was added in fresh mTeSR1 medium. On day 0, the culture medium was replaced with N2/DMEM/F12/NEAA (Invitrogen) containing doxycycline (2 g/l, Clontech) to induce TetO gene expression, and the culture was retained in the medium for ~2 weeks. On day 1, a 3-d drug-resistance selection period was started. On day 6, mouse glial cells were plated on matrigel-coated coverslips (~5 × 104 cells/well of 24-well plate). On day 7, iN cells were dissociated using Accutase and plated on coverslips (~3 × 105 cells/well of 24-well plate) in Neurobasal medium supplemented with B27/Glutamax (Invitrogen) containing BDNF (20ng/ml, Peprotech). Around day 10, Ara-C (2 g/l, Sigma)
