Effects of CSE exposure (24 h) on BBB endothelial gene and protein expression of HMOX1. a Several genes belonging to HMOX-1 and heme recycling were up-regulated following CSE exposure of TS products. Nicotine did not produce any change in these genes; b real time RT-PCR showed up-regulation of HMOX-1 protein expression following exposure to full flavor, and ULN CSEs; c western blot analyses of cellular membrane fractions corroborate with mRNA changes showing statistically significant up-regulation in protein expression; representative western blots were shown with actin as a loading control; d immunofluorescence analysis of HMOX1 expression. Data were expressed as mean ± SEM (fold change over control). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs. control. n = 6 biological replicates/condition.