Gene expression analysis of the hall mark proteins related to brain capillary endothelial cells (BCECs). RNA was obtained from BCECs grown in mono- (blue), co- (red) and triple- (green) culture conditions at day 1 and analysed for the expression of BCECs hallmark genes (claudin-5, occludin, PECAM-1, ABCG2, ABCB1 and Transferrin receptor 1 (TfR1)). The relative gene expression among the three culture conditions was statistically analysed using 1-way ANOVA with Tukey’s multiple comparisons post hoc test. Data are presented as sample means ± SEM (n = 8). p < 0.05, **p < 0.01, ***p < 0.001.