Background

The aryl hydrocarbon receptor (AHR) and autophagy are both important to maintain skin homeostasis. However, they are also involved in skin disorders. So far, their roles in psoriasis pathogenesis are unknown.

Objective

We studied the immunohistochemical and gene expression of AHR, CYP1A1, and microtubule-associated protein light chain 3 (LC3) in lesional skin of psoriasis patients to determine correlations among them.

Methods

We included 24 psoriasis patients and ten healthy volunteers. Skin biopsies were collected. AHR, CYP1A1, and LC3 protein expression was examined by immunohistochemistry, immunofluorescence, and western blotting. AHR, CYP1A1, LC3, ATG5, BECN1 and Nrf2 mRNA levels were measured by quantitative polymerase chain reaction.

Results

AHR and CYP1A1 protein expression were higher in psoriasis lesional skin than in normal skin. LC3 protein expression was lower in psoriasis lesions than in normal controls. AHR and CYP1A1 protein expression in psoriasis lesions showed significant positive correlations with mean epidermal thickness and inflammatory cell density. Significant negative correlations were noted between LC3 protein expression in psoriasis lesions and the mean epidermal thickness or inflammatory cell density. A significant negative correlation was found between AHR and LC3 expression in psoriatic skin. AHR, CYP1A1 and Nrf2 mRNA expression were upregulated while LC3, ATG5, and BECN1 mRNA were down-regulated, in psoriatic lesional skin compared with normal controls.

Conclusion

AHR and autophagy could play a role in psoriasis pathogenesis by modifying epidermal hyperproliferation and inflammation. AHR and autophagy regulation are potential therapeutic targets in chronic inflammatory skin diseases.