title: Gene regulation by 1,25-dihydroxyvitamin D3 in CD4+CD25+ cells is enabled by IL-2.
abstract: Vitamin D may be responsible for reducing the development and severity of autoimmune and allergic diseases. Topically applied 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) enhances the immunoregulatory ability of CD4+CD25+ T cells residing in the skin-draining lymph nodes (SDLNs) of mice. The mechanisms responsible were investigated by examining the expression of 84 cytokine and cytokine-related genes in a 96-well gene array. CD4+CD25+ cells isolated from the SDLNs of BALB/c mice, 24 and 96  hours after topical treatment with 1,25(OH)(2)D(3), consistently expressed increased IL-2 mRNA levels and also secreted enhanced quantities of IL-2 after ex vivo stimulation with phorbol 12-myristate 13-acetate and ionomycin. CD4+CD25+ cells from the lymph nodes of naive mice constitutively express the vitamin D receptor, allowing direct modulation by 1,25(OH)(2)D(3). However, in vitro treatment with 1,25(OH)(2)D(3) did not modify the expression of 84 tested cytokine and cytokine-related mRNAs. It was only in the presence of IL-2 that 1,25(OH)(2)D(3) increased the expression of genes including IL-2 and TLR4. Further, 1,25(OH)(2)D(3) enhanced the ability of IL-2 to stimulate CD4+CD25+ cells to proliferate in vitro and also regulate contact hypersensitivity responses on adoptive transfer into naive mice. Therefore, 1,25(OH)(2)D(3) enabled by IL-2 can directly enhance the regulatory potential of CD4+CD25+ T cells to control immune disease.
authors.affiliation: Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia. shelleyg@ichr.uwa.edu.au
authors.forename: Shelley
authors.initials: S
authors.lastname: Gorman
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Judge
authors.forename: Prue H
authors.initials: PH
authors.lastname: Hart
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001327:Autoimmune Diseases / Q000188:drug therapy / Q000235:genetics / Q000276:immunology; D015704:CD4 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D002117:Calcitriol / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D016207:Cytokines / Q000235:genetics*; D017449:Dermatitis, Allergic Contact / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000235:genetics* / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000235:genetics
chemical_list: D015704:CD4 Antigens; D016207:Cytokines; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D002117:Calcitriol