Figure 6.

Aryl hydrocarbon receptor (AhR)-dependent interleukin-33 (IL-33) induction in mouse bone marrow-derived macrophages. A, The mouse IL-33 gene includes 2 exon 1 variants, 1a and 1b (Talabot-Ayer et al., 2012). The position of each exon is described. Two mRNA variants containing exons 1a or 1b are registered in the GenBank as variant 2 (IL-33a) or variant 1 (IL-33b), respectively, and are translated into the same protein because exons 2 (includes the start codon) to 8 are common between the 2 variants. B, Dioxin response element (DRE) core sequences were identified in the mouse IL-33 promoter region. C, Mouse bone marrow-derived macrophages prepared from wild-type or AhR-null mice were treated with 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) (10 nM) and 6-Formylindolo(3, 2-b)carbazole (FICZ) (100 nM) for 6 h. Total RNA was extracted from the cells, and real-time PCR was subsequently performed to measure IL-33b mRNA expression. The values represent the mean ± SE (n = 4–5). Data were analyzed using a one-way analysis of variance (ANOVA), followed by Dunnett's test or a t test. *p < .05, **p < .01 versus the untreated group. #p < .05, ##p < .01 versus the wild-type group. D, Mouse alveolar macrophages were treated with TCDD (10 nM), FICZ (100 nM), or KYN (50 μM) for 6 h and then IL-33b expression was evaluated by real-time PCR. The values represent the mean ± SE (n = 5). Data were analyzed using a one-way ANOVA, followed by Dunnett's test. *p < .05, **p < .01 versus the untreated group.