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

Figure 9 Reactive oxygen species mediated Bacteroides fragilis enterotoxin-induced heme oxygenase-1 expression in dendritic cells. A: DC2.4 cells were stimulated with BFT (100 ng/mL) in the absence or presence of the antioxidant N-acetyl-L-cysteine (NAC, 0.5 mmol/L) for 6 h. Production of reactive oxygen species (ROS) was measured by a commercially available ROS detection kit. Data are expressed as mean fold induction ± SE (%) relative to untreated controls (n = 5). ^aP < 0.05. B: DC2.4 cells were stimulated with BFT (100 ng/mL) in the absence or presence of NAC (0.5 mmol/L) for 30 min (phospho-ERK and phospho-p38), 3 h (phospho-Nrf2), or 24 h (heme oxygenase-1, HO-1). The effects of NAC on each protein level were determined using immunoblot. Results are representative of three independent experiments. NAC: N-acetyl-L-cysteine; HO-1: Heme oxygenase-1; BFT: Bacteroides fragilis toxin.