< b > < i > Staphylococcus aureus < /i > < /b > Activates the Aryl Hydrocarbon Receptor in Human Keratinocytes

Staphylococcus aureus is an important pathogen causing various infections, including – as most frequently isolated bacterium – cutaneous infections. Keratinocytes as the first barrier cells of the skin respond toS. aureus by the release of defense molecules such as cytokines and antimicrobial peptides. Although several pattern recognition receptors expressed in keratinocytes such as Toll-like and NOD-like receptors have been reported to detect the presence ofS. aureus, the mechanisms underlying the interplay betweenS. aureus and keratinocytes are still emerging. Here, we report thatS. aureus induced gene expression of CYP1A1 and CYP1B1, responsive genes of the aryl hydrocarbon receptor (AhR). AhR activation byS. aureus was further confirmed by AhR gene reporter assays. AhR activation was mediated by factor(s) #x3c;2 kDa secreted byS. aureus. Whole transcriptome analyses and real-time PCR analyses identified IL-24, IL-6, and IL-1beta as cytokines induced in an AhR-dependent manner inS. aureus-treated keratinocytes. AhR inhibition in a 3D organotypic skin equivalent confirmed the crucial role of the AhR in mediating the induction of IL-24, IL-6, and IL-1beta upon stimulation with livingS. aureus. Taken together, we further highlight the important role of the AhR in cutaneous innate defense and identified the AhR as a novel receptor mediating the sensing of the important skin pathogenS. aureus in keratinocytes.J Innate Immun
Source: Journal of Innate Immunity - Category: Allergy & Immunology Source Type: research