We used the human iPSC lines 201B6 and 836B3 (Takahashi et al., 2007). The methods for culturing and passaging human iPSCs were reported previously (Masumoto et al., 2014). hCMEC/D3 (Millipore) was cultured with EGM2 (Lonza) and 5% fetal bovine serum (FBS) (Life Technologies). HUVEC (Lonza) was cultured with EGM2 (Lonza).