title: Ultraviolet-B radiation upregulates expression of dectin-2 on epidermal Langerhans cells by activating the gene promoter.
abstract: Epidermal Langerhans cells (LC) belong to the antigen-presenting cell (APC) family of dendritic cells that can initiate antigen-specific immunogenic or tolerogenic responses. In mice, we have shown ultraviolet-B (UV-B) irradiation to induce long-lasting suppression (tolerance) of contact hypersensitivity responses by converting LC from immunogenic to tolerogenic APC. The C-type lectin receptor, dectin-2, expressed preferentially by LC and dendritic cells, has also been shown to be involved in inducing this form of UV-B-induced immunosuppression. These observations led us to question whether UV-B can modulate dectin-2 expression by LC. In ICR mice engineered to express the dectin-2 gene promoter linked to a luciferase reporter gene, we found broadband UV-B treatment in vivo to activate the promoter in LC. In wild-type C3H/HeN mice, we found such treatment in vivo to yield LC with increased dectin-2 expression at both mRNA and protein levels. Broadband UV-B treatment in vitro of bone marrow-derived dendritic cells from these mice also showed upregulated expression of dectin-2 mRNA. These findings lead us to conclude that broadband UV-B upregulates dectin-2 expression in LC by activating the dectin-2 gene promoter. Such amplification suggests that UV-B-induced immunosuppression may be due (at least in part) to augmented dectin-2 expression in LC.
authors.affiliation: Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9069, USA.
authors.forename: Makoto
authors.initials: M
authors.lastname: Bonkobara
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yagihara
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yudate
authors.forename: Jin-Sung
authors.initials: JS
authors.lastname: Chung
authors.forename: Tsukimi
authors.initials: T
authors.lastname: Washizu
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ariizumi
authors.forename: Ponciano D
authors.initials: PD
authors.lastname: Cruz
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000528:radiation effects; D003713:Dendritic Cells / Q000528:radiation effects; D005260:Female; D005786:Gene Expression Regulation / Q000528:radiation effects*; D007801:Langerhans Cells / Q000502:physiology* / Q000528:radiation effects; D037181:Lectins, C-Type / Q000235:genetics*; D051379:Mice; D008809:Mice, Inbred C3H; D008813:Mice, Inbred ICR; D011401:Promoter Regions, Genetic / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D037181:Lectins, C-Type; C445340:dectin-2, mouse