Aryl Hydrocarbon Receptor Directly Regulates Artemin Gene Expression

ABSTRACT

Transgenic mice expressing a constitutively active form of the aryl hydrocarbon receptor in keratinocytes (AhR-CA mice) develop severe dermatitis that substantially recapitulates the pathology of human atopic dermatitis. The neurotrophic factor artemin (Artn) is highly expressed in the epidermis of AhR-CA mice and causes hypersensitivity to itch (alloknesis) by elongating nerves into the epidermis. However, whether the Artn gene is regulated directly by AhR or indirectly through complex regulation associated with AhR remains unclear. To this end, we previously conducted chromatin immunoprecipitation-sequencing analyses of the Artn locus and found a xenobiotic response element (XRE) motif located far upstream (52 kb) of the gene. Therefore, in this study, we addressed whether the XRE actually regulates the Artn gene expression by deleting the region containing the motif. We generated two lines of Artn^ΔXRE mice. In the mouse epidermis, inducible expression of the Artn gene by the AhR agonist 3-methylcholanthrene was substantially suppressed compared to that in wild-type mice. Importantly, in AhR-CA::Artn^ΔXRE mice, Artn expression was significantly suppressed, and alloknesis was improved. These results demonstrate that the Artn gene is indeed regulated by the distal XRE-containing enhancer, and alloknesis in AhR-CA mice is provoked by the AhR-mediated direct induction of the Artn gene.

KEYWORDS:

• AhR
• alloknesis
• artemin
• atopic dermatitis
• skin

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Articles of Significant Interest in This Issue

ACKNOWLEDGMENTS

We thank Junji Takeda (Osaka University) for providing the K5Cre mouse and Masanobu Morita, Eriko Naganuma, Hiromi Suda, and Nanae Osanai (Tohoku University) for technical support.

This study was supported by funding from MEXT/JSPS KAKENHI (26111002 and 19H05649, M.Y.), AMED-CREST, AMED (M.Y.), and the JSPS Research Fellowship for Young Scientists (19J10035, T.E.).