Ultraviolet-B radiation upregulates expression of dectin-2 on epidermal Langerhans cells by activating the gene promoter.
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.
Bonkobara
Makoto
M
Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9069, USA.
Yagihara
Hiroko
H
Yudate
Tatsuo
T
Chung
Jin-Sung
JS
Washizu
Tsukimi
T
Ariizumi
Kiyoshi
K
Cruz
Ponciano D
PD
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
D037181:Lectins, C-Type; C445340:dectin-2, mouse