Figure 5. Acrolein promotes Foxp3+ expression via activation of the aryl-hydrocarbon receptor.

(A) NF-κB inhibition was measured with monocytic THP1-XBlue cells, which were treated with LPS and increasing concentrations of acrolein or cinnamaldehyde for 18 hours. Bars represent summary from two independent experiments normalized to cells stimulated with LPS alone. (B) AZ-AhR cells were treated with different concentrations of acrolein or cinnamaldehyde crotonaldehyde, propanal and methacrolein in increasing concentrations (0.018/0.18/1.8/9/18/45/90/180 μM), with (C) acrolein alone or in combination with the antagonists resveratrol or 3′-methoxy-4′-nitroflavone for 18 h, before luciferase-activity was measured in the supernatant. Bars represent data from three independent experiments normalized to medium alone for B and two independent experiments for C. Data presented as mean ± SD, Statistical analyses was made using 2way RM ANOVA following Sidak’s multiple comparisons test, respectively. Significances to controls are depicted. (D) PBMCs were stimulated for 72 h with cinnamaldehyde, acrolein and or resveratrol. Gating Strategy and summary of % of CD4+CD25+Foxp3+ cells as determined by FACS of 5 independent experiments (n = 15). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.001.