Intestinal exposure to PCB 153 induces inflammation via the ATM/NEMO pathway

Background: Polychlorinated biphenyls (PCBs) are persistent organic pollutants that adversely affect human health. PCBs bio-accumulate in organisms important for human consumption. PCBs accumulation in the body leads to activation of the transcription factor NF-kappa B, a major driver of inflammation. Despite dietary exposure being one of the main routes of exposure to PCBs, the gut has been widely ignored when studying the effects of PCBs. Objectives: We investigated the effects of PCB 153 on the intestine and addressed whether PCB 153 affected intestinal permeability or inflammation and the mechanism by which this occurred. Methods: Mice were orally exposed to PCB 153 and gut permeability was assessed. Intestinal epithelial cells (IECs) were collected and evaluated for evidence of genotoxicity and inflammation. A human IEC line (SW480) was used to examine the direct effects of PCB 153 on epithelial function. NF-kappa B activation was measured using a reporter assay, DNA damage was assessed, and cytokine expression was ascertained with real-time PCR. Results: Mice orally exposed to PCB 153 had an increase in intestinal permeability and inflammatory cytokine expression in their IECs; inhibition of NF-kappa B ameliorated both these effects. This inflammation was associated with genotoxic damage and NF-kappa B activation. Exposure of SW480 cells to PCB 153 led to similar effects as seen in vivo. We found that activation of the ATM/NEMO pathway by genotoxic stress was upstream of NF-kappa B activation. Conclusions: These results demonstrate that oral exposure to PCB 153 is genotoxic to IECs and induces downstream inflammation and barrier dysfunction in the intestinal epithelium.