title: Converging pathways lead to overproduction of IL-17 in the absence of vitamin D signaling.
abstract: Multiple pathways converge to result in the overexpression of T(h)17 cells in the absence of either vitamin D or the vitamin D receptor (VDR). CD4(+) T cells from VDR knockout (KO) mice have a more activated phenotype than their wild-type (WT) counterparts and readily develop into T(h)17 cells under a variety of in vitro conditions. Vitamin D-deficient CD4(+) T cells also overproduced IL-17 in vitro and 1,25 dihydroxyvitamin D(3) inhibited the development of T(h)17 cells in CD4(+) T-cell cultures. Conversely, the induction of inducible (i) Tregs was lower in VDR KO CD4(+) T cells than WT and the VDR KO iTregs were refractory to IL-6 inhibition. Host-specific effects of the VDR were evident on in vivo development of naive T cells. Development of naive WT CD4(+) T cells in the VDR KO host resulted in the overexpression of IL-17 and more severe experimental inflammatory bowel disease (IBD). The increased expression of T(h)17 cells in the VDR KO mice was associated with a reduction in tolerogenic CD103(+) dendritic cells. The data collectively demonstrate that T(h)17 and iTreg cells are direct and indirect targets of vitamin D. The increased propensity for development of T(h)17 cells in the VDR KO host results in more severe IBD.
authors.affiliation: Center for Molecular Immunology and Infectious Disease, Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Danny
authors.initials: D
authors.lastname: Bruce
authors.forename: Sanhong
authors.initials: S
authors.lastname: Yu
authors.forename: Jot Hui
authors.initials: JH
authors.lastname: Ooi
authors.forename: Margherita T
authors.initials: MT
authors.lastname: Cantorna
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology; D007108:Immune Tolerance / Q000235:genetics / Q000276:immunology; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020381:Interleukin-17 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D015850:Interleukin-6 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018167:Receptors, Calcitriol / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D058504:Th17 Cells / Q000276:immunology / Q000378:metabolism; D014807:Vitamin D / Q000031:analogs & derivatives / Q000276:immunology / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D015850:Interleukin-6; D018167:Receptors, Calcitriol; C118756:dihydroxy-vitamin D3; D014807:Vitamin D