Fig. 4

Differentiated primary human bAEC exposed to WFSE exhibit a reduction in TJ proteins. a Western analysis of tight junction proteins from primary human airway epithelial cells grown at an air-liquid interface showing a reduction in ZO-1 and Claudin-1 for the 5% wildfire smoke extract (WFSE) exposure after 6 h. While the abundance of Occludin-1 followed a similar trend for 5% WFSE exposure, its downregulation did not reach significance in this model. Apoptosis as evidenced by the cleavage of the caspase-3 substrate Poly (ADP-ribose) polymerase (PARP) was not detected. As significant apoptosis was not anticipated, a doxorubicin exposure (1 μM) was included to produce a caspase-mediated apoptotic outcome as a positive control to identify the products of caspase-3-mediated PARP cleavage in the western blot. b Histogram analyses of protein expression density scores. Protein expression was baselined to the abundance in the untreated sample, and normalized to the expression of β-actin. Intervals are 95% CI, and significance compared to the control sample can be identified when confidence intervals do not intersect 1 for the Y-axis. *, P ≤ 0.05; **, P ≤ 0.01 for n = 3 experiments using cells derived from different participants