We next tested the efficacy of this protocol across 42 NPC lines from 30 individuals (including healthy controls as well as cases with schizophrenia and frontotemporal dementia; 16 male and 14 female) generated as part of three unique hiPSC cohorts (reprogrammed and differentiated through different protocols in independent laboratories) (Table S2). All 42 NPC lines ultimately yielded replicative cells with an astrocyte-like morphology (although not necessarily on the first attempt), with an average composition of 90% S100β+ and 82% GFAP+ cells by flow cytometry, relative to the appropriate secondary antibody control (Figures 1A and 1B; hiPSCs served as a negative control, lacking S100β- and GFAP-positive cells), and confirmed by immunocytochemistry (Figures 1A, 1C, S1J, and S1K). As with primary astrocytes (Figures 1G and S1O), there is substantial variability in mean fluorescent intensity between S100β- and GFAP-positive hiPSC-astrocyte populations (Figure 1A).
