Schematic illustration of the experimental design of BBB models that were used in this study. “EC_only“: endothelial cells (ECs) are plated on the apical side of a 24-well-plate insert with a pore-size of 0.4 μm. “indirect“: Pericytes (PCs) are plated on the basolateral side of the insert, and in a second step (after 3 h), ECs are plated on the apical side, allowing contact of the two cell types through the membrane. “PC_EC direct“: PCs are plated on the apical side of inserts first, and after 3 h, ECs are plated on top of PCs. “EC_PC direct“: ECs are plated first, and after 3 h, PCs are seeded on top of them.