An Environmental Contaminant, Benzo(a)pyrene, Induces Oxidative Stress-mediated Interleukin-8 Production in Human Keratinocytes Via the Aryl Hydrocarbon Receptor Signaling Pathway

Background: Benzo(a)pyrene (BaP) is an environmental contaminant found in cigarette smoke. It is well known that cigarette smoking exacerbates interleukin-8 (IL-8)-related inflammatory skin diseases such as psoriasis, palmoplantar pustulosis and acne. Although BaP has been shown to exert its biological effects via the aryl hydrocarbon receptor (AhR) signaling pathway, the mechanism of its inflammatory effects on skin remains unanswered.

Objective: To elucidate whether or not BaP cause AhR activation and subsequent oxidative stress leading to IL-8 production in normal human epidermal keratinocytes (NHEKs).

Methods: NHEKs exposed to BaP were analyzed. Immunofluorescence, real-time PCR, Western blotting, ELISA, reactive oxygen species (ROS) detection using H2DCFDA and RNA interference using si (small interfering) RNA were employed.

Results: This data highlights AhR-ROS-dependent regulation of IL-8 in NHEKs by BaP, providing a plausible explanation, at least in part, for why cigarette smoking exacerbates IL-8-related skin diseases such as psoriasis, palmoplantar pustulosis and acne.