Figure 7.

Pre-exposure to aerosolized e-cig nicotine increased RSV-induced airway epithelial barrier disruption. Confluent 16HBE cells were exposed to aerosolized e-cig nicotine and HEPA-filtered air three times for 24 h, followed by RSV infection (rrRSV derived from the RSV A2 strain) at a multiplicity of infection (MOI) of 0.25 for 24 h. A and B: at 24 h post-RSV infection, the expression of RFP (red fluorescent protein, a representative of viral replication) in infected 16HBE cells was visualized by an inverted fluorescence microscope and quantified by Image J. C: TEER (Ω × cm²) was measured by the volt-ohm meter and plotted as a percentage change from time 0. D: 16HBE cells were fixed with methanol and immunolabeled for tight junction proteins (ZO-1 and occludin) and adherens junction proteins (E-cadherin and β-catenin) and imaged by confocal microscopy. Data are presented as means ± SE, n = 8, one-way ANOVA followed by Dunnett’s multiple comparisons test. *P < 0.05, ****P < 0.0001. The images are representative of at least three independent experiments. Scale bar, in B = 100 μm and D = 30 μm. RSV, respiratory syncytial virus; TEER, transepithelial electrical resistance.