Figure 5.

Chronic exposure to nicotine-free e-cigarette induces the expression of pro-inflammatory cytokines in the human colonic epithelium

(A) Schematic displays the overall experimental design for assessing how e-cig affects the gut epithelial response to infectious pathogenic microbes, e.g., E. coli strain AIEC-LF-82.

(B–F) Bar graphs display the relative fold change (compared to media control) in the levels of mRNA for pro-inflammatory cytokines. Data are shown as mean ± SEM (n = 3 independent experiments). Statistical significance was estimated using one-way ANOVA with Tukey's test; ∗p<0.05, ∗∗p <0.01.

(G and H) Bar graphs display the concentration of IL-8 (G) and MCP-1 (H) released in the basolateral compartment of polarized EDMs after exposure to e-cig vapor-infused media. Data are shown as mean ± SEM (n = 3 independent experiments). Statistical significance was estimated using one-way ANOVA with Tukey's test; ∗p<0.05 and ∗∗p <0.01.

(I) Bar graphs display the bacterial load internalized in EDMs pretreated as indicated with or without single or repeated exposure to e-cig vapor-infused media and then exposed to pathogenic AIEC-LF82 for 3 h. Data are expressed as the number of internalized bacteria to the infected control EDMs (untreated; i.e., not exposed to e-cig) and is represented as the mean ± SEM of three separate experiments. Statistical significance was estimated using one-way ANOVA with Tukey's test;∗∗∗∗ p< 0.0001.

(J) Bar graphs display cellular accumulation of ROS, as determined by measuring the levels of oxidized DNA in the supernatant in the basolateral compartment of polarized EDMs after exposure to the indicated treatments. Data are represented as the mean ± SEM of three separate experiments. Statistical significance was estimated using one-way ANOVA with Tukey's test; ∗p<0.05.