Bacteroides fragilis enterotoxin upregulates heme oxygenase-1 in dendritic cells via reactive oxygen species-, mitogen-activated protein kinase-, and Nrf2-dependent pathway

Figure 4 Relationship between the suppression of NF-κB or AP-1 activity and heme oxygenase-1 expression in bone marrow-derived dendritic cells stimulated with Bacteroides fragilis enterotoxin. A: Bone marrow (BM)-derived dendritic cells (DCs) were treated with Bacteroides fragilis toxin (BFT) (100 ng/mL) for 24 h, respectively. The expression of heme oxygenase-1 (HO-1) and actin was analyzed by immunoblot. Results are representative of more than three independent experiments. B: BM-derived DCs were preincubated with the NF-κB inhibitor Bay 11-7082 (50 μmol/L) or the AP-1 inhibitor SR11302 (10 μmol/L) for 30 min, followed by stimulation with BFT (100 ng/mL) for an additional 24 h. Expression levels of HO-1 protein were measured by ELISA (mean ± SE, n = 5). NS: Statistically non-significant; HO-1: Heme oxygenase-1; BFT: Bacteroides fragilis toxin.