proved critical to the ultimate successful differentiation of hiPSC-astrocytes. By both fluorescence-activated cell sorting and qPCR, GFAP seems to be a more variable marker of astrocyte fate (Figures 1A and 1B) and we recommend instead using S100β when evaluating hiPSC-astrocyte populations; moreover, more than any single gene, using panels of markers and/or global transcriptomic analysis more fully reveals the extent of astrocyte patterning of each line. We also suggest that hiPSC-astrocyte response to inflammatory stimuli might represent a simple and easy platform by which to confirm the functionality of hiPSC-astrocytes; astrocytes undergo stimulation-dependent cytokine secretion, while NPCs do not secrete cytokines.
