Fig. 2

Inhibition of autophagic flux and apoptotic changes in primary SAEC exposed to WFSE. a Small airway epithelial cells subject to 10% wildfire smoke extract (WFSE) for 6 h undergo apoptotic changes as evidenced by the cleavage of the caspase-3 substrate Poly (ADP-ribose) polymerase (PARP). This may be due to the decrease in the inhibitor of the extrinsic apoptotic pathway Bcl2, and a blockade in normal autophagic flux as determined by the increase in the essential autophagy protein Microtubule-Associated Protein 1A/1B-Light Chain-3-II (LC3-II; lower band), simultaneous with increased Sequestosome, which is degraded with the cargo it shuttles to the autophagosome. While 10% cigarette smoke extract (CSE) also initiated an apoptotic response concomitant with a reduction in Bcl2, this was not accompanied by a block in autophagic flux, as Sequestosome abundance remained relatively low in relation to the elevation in LC3-II. The expression of the pro-inflammatory transcription factor NF-κβ subunit (p65) did not significantly increase in this model. 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 ***, P ≤ 0.001 for n = 3 experiments