Supplementary Figure 5: Epidermal activation of AhR by air pollutants causes AD-like phenotypes through artemin expression and hyper-innervation into the epidermis.

Schema of AhR-mediated development and the exacerbation of AD. Note that AhR is activated by air pollutants, such as traffic-derived particulate matter. Activated AhR induces the expression of TSLP, IL-33 and ARTEMIN in keratinocytes. ARTEMIN induces hyper-innervation of the epidermis by sensory nerves, resulting in alloknesis. Subsequent scratching behaviors lead to barrier damage and increased antigen penetration, resulting in enhanced sensitization that promotes a predisposition to other allergic diseases.