title: Activity of 25-hydroxylase in human gingival fibroblasts and periodontal ligament cells.
abstract: BACKGROUND
  We previously demonstrated that 25-hydroxyvitamin D(3) concentrations in gingival crevicular fluid are 300 times higher than those in the plasma of patients with aggressive periodontitis. Here we explored whether 25-hydroxyvitamin D(3) can be synthesized by periodontal soft tissue cells. We also investigated which of the two main kinds of hydroxylases, CYP27A1 and CYP2R1, is the key 25-hydroxylase in periodontal soft tissue cells.
  
  
  RESULTS
  Primary cultures of human gingival fibroblasts and periodontal ligament cells from 5 individual donors were established. CYP27A1 mRNA, CYP2R1 mRNA and CYP27A1 protein were detected in human gingival fibroblasts and periodontal ligament cells, whereas CYP2R1 protein was not. After incubation with the 25-hydroxylase substrate vitamin D(3), human gingival fibroblasts and periodontal ligament cells generated detectable 25-hydroxyvitamin D(3) that resulted in the production of 1α,25-dihydroxyvitamin D(3). Specific knockdown of CYP27A1 in human gingival fibroblasts and periodontal ligament cells using siRNA resulted in a significant reduction in both 25-hydroxyvitamin D(3) and 1α,25-dihydroxyvitamin D(3) production. Knockdown of CYP2R1 did not significantly influence 25-hydroxyvitamin D(3) synthesis. Sodium butyrate did not influence significantly CYP27A1 mRNA expression; however, interleukin-1β and Porphyromonas gingivalis lipopolysaccharide strongly induced CYP27A1 mRNA expression in human gingival fibroblasts and periodontal ligament cells.
  
  
  CONCLUSIONS
  The activity of 25-hydroxylase was verified in human gingival fibroblasts and periodontal ligament cells, and CYP27A1 was identified as the key 25-hydroxylase in these cells.
authors.affiliation: Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Kaining
authors.initials: K
authors.lastname: Liu
authors.forename: Huanxin
authors.initials: H
authors.lastname: Meng
authors.forename: Jianxia
authors.initials: J
authors.lastname: Hou
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D002112:Calcifediol / Q000235:genetics / Q000378:metabolism; D002117:Calcitriol / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D053493:Cholestanetriol 26-Monooxygenase / Q000235:genetics / Q000378:metabolism; D000072467:Cytochrome P450 Family 2; D005347:Fibroblasts / Q000201:enzymology*; D005881:Gingiva / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D010513:Periodontal Ligament / Q000166:cytology / Q000201:enzymology*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D000072467:Cytochrome P450 Family 2; C506833:CYP2R1 protein, human; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol; D002112:Calcifediol