Antioxidant Artemisia princeps Extract Enhances the Expression of Filaggrin and Loricrin via the AHR/OVOL1 Pathway.

The Japanese mugwort, ( in Japanese), has anti-inflammatory and antioxidant effects. Skin care products containing extract (APE) are known to improve dry skin symptoms in atopic dermatitis. Atopic dry skin is associated with a marked reduction of skin barrier proteins, such as filaggrin (FLG) and loricrin (LOR). Recently, aryl hydrocarbon receptor (AHR), and its downstream transcription factor OVO-like 1 (OVOL1), have been shown to regulate the gene expression of FLG and LOR. The focus of this paper is to evaluate the effects of APE on the AHR/OVOL1/FLG or LOR pathway since they have remained unknown to this point. We first demonstrated that non-cytotoxic concentrations of APE significantly upregulated antioxidant enzymes, NAD(P)H dehydrogenase quinone 1 and heme oxygenase 1, in human keratinocytes. Even at these low concentrations, APE induced nuclear translocation of AHR and significantly upregulated (a specific target gene for AHR activation), , and expression. AHR knockdown downregulated expression. The APE-induced upregulation of and was canceled in keratinocytes with AHR or OVOL1 knockdown. In conclusion, antioxidant APE is a potent phytoextract that upregulates and expression in an AHR/OVOL1-dependent manner and this may underpin the barrier-repairing effects of APE in treating atopic dry skin.