title: Characterization of the autocrine/paracrine function of vitamin D in human gingival fibroblasts and periodontal ligament cells.
abstract: BACKGROUND
  We previously demonstrated that 25-hydroxyvitamin D(3), the precursor of 1α,25-dihydroxyvitamin D(3), is abundant around periodontal soft tissues. Here we investigate whether 25-hydroxyvitamin D(3) is converted to 1α,25-dihydroxyvitamin D(3) in periodontal soft tissue cells and explore the possibility of an autocrine/paracrine function of 1α,25-dihydroxyvitamin D(3) in periodontal soft tissue cells.
  
  
  RESULTS
  We established primary cultures of human gingival fibroblasts and human periodontal ligament cells from 5 individual donors. We demonstrated that 1α-hydroxylase was expressed in human gingival fibroblasts and periodontal ligament cells, as was cubilin. After incubation with the 1α-hydroxylase substrate 25-hydroxyvitamin D(3), human gingival fibroblasts and periodontal ligament cells generated detectable 1α,25-dihydroxyvitamin D(3) that resulted in an up-regulation of CYP24A1 and RANKL mRNA. A specific knockdown of 1α-hydroxylase in human gingival fibroblasts and periodontal ligament cells using siRNA resulted in a significant reduction in both 1α,25-dihydroxyvitamin D(3) production and mRNA expression of CYP24A1 and RANKL. The classical renal regulators of 1α-hydroxylase (parathyroid hormone, calcium and 1α,25-dihydroxyvitamin D(3)) and Porphyromonas gingivalis lipopolysaccharide did not influence 1α-hydroxylase expression significantly, however, interleukin-1β and sodium butyrate strongly induced 1α-hydroxylase expression in human gingival fibroblasts and periodontal ligament cells.
  
  
  CONCLUSIONS
  In this study, the expression, activity and functionality of 1α-hydroxylase were detected in human gingival fibroblasts and periodontal ligament cells, raising the possibility that vitamin D acts in an autocrine/paracrine manner in these cells.
authors: Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China.
authors: Kaining
authors: K
authors: Liu
authors: Huanxin
authors: H
authors: Meng
authors: Jianxia
authors: J
authors: Hou
mesh_terms: D002478:Cells, Cultured; D005881:Gingiva / Q000166:cytology / Q000502:physiology*; D006801:Humans; D010513:Periodontal Ligament / Q000166:cytology / Q000502:physiology*; D014807:Vitamin D / Q000502:physiology*
chemical_list: D014807:Vitamin D