In the case of TJ proteins, the scenario is more variegated: occludin and ZO-1 were equally decreased in AC GBM/BBB and NS GBM/BBB co-cultures, claudin-3 and claudin-5 were unchanged and increased, respectively, in AC GBM/BBB co-cultures, and both increased in NS GBM/BBB co-cultures (Fig. 1c, Supplementary Figure S2b). Here, CLDN5 is linked to glioblastoma.