The opposite effect of tapinarof between IMQ and IL‐23 induced psoriasis mouse models

Abstract Tapinarof is an aryl hydrocarbon receptor (AHR) ligand which is used to treat plaque psoriasis in adults. However, the underlying mechanism is not yet fully understood. In this study, we applied two of the most studied psoriasis mouse models: topical application of imiquimod (IMQ) and subcutaneous injection of IL‐23. Although both models successfully induced psoriasis‐like lesions in mice, tapinarof had a completely opposite effect on the two models. Tapinarof decreased the expression of multiple essential cytokines involved in the pathological IL‐23/IL‐17/IL‐22 axis and ameliorated IMQ‐induced psoriatic dermatitis, inhibiting keratinocyte proliferation and abnormal differentiation. However, in the IL‐23‐injection‐model, tapinarof instead aggravated the disease. Here, tapinarof increased epidermal thickness and differentiated epidermal dysplasia in mice. Our data suggest that tapinarof may have different effects on varied types of psoriasis.