title: 1α,25-Dihydroxyvitamin D3 inhibits osteoblastic differentiation of mouse periodontal fibroblasts.
abstract: OBJECTIVE
  Periodontal ligament (PDL) is a non-mineralized tissue connecting cementum and alveolar bone. Recent studies have suggested that periodontal fibroblasts can differentiate into mineralized tissue-forming cells such as osteoblasts and cementoblasts. We elucidated the immunolocalization of vitamin D receptor (VDR) and the effects of vitamin D(3) (VD(3)) on mouse periodontal fibroblasts to clarify the role of VDR and VD(3) in the differentiation of periodontal fibroblasts.
  
  
  METHODS
  Immunohistochemical analysis using anti-VDR antibody was performed in paraffin sections of mouse mandibles at E13, E14, E17, P10, and P35. The roles of VD(3) in osteoblastic differentiation and mineralization were estimated by alkaline phosphatase (ALP) and alizarin red (AR) staining. In addition, the mRNA expression of osteoblast markers and mineralization inhibitors was examined by real-time PCR.
  
  
  RESULTS
  At the bud, cap and early bell stages, immunoreactivity for VDR was scarcely seen in the cells of dental follicles. Labelling was detected in the nuclei of cemetoblasts, periodontal fibroblasts and osteoblasts during root formation. VD(3) inhibited ALP activity and AR-positive mineralized nodule formation of periodontal fibroblasts in osteogenic culture medium. Real-time PCR revealed that VD(3) down-regulated the levels of osteoblast markers. In contrast, VD(3) significantly up-regulated the level of periodontal ligament associated protein (PLAP)-1, a negative regulator of osteoblastic differentiation.
  
  
  CONCLUSIONS
  These results suggest that VD(3) negatively regulates the osteoblastic differentiation of mouse periodontal fibroblasts and prevents the periodontal ligament from mineralization via increase of PLAP-1.
authors: Graduate School of Oral Medicine, Matsumoto Dental University, Nagano, Japan.
authors: Yen-Chen
authors: YC
authors: Chen
authors: Tadashi
authors: T
authors: Ninomiya
authors: Akihiro
authors: A
authors: Hosoya
authors: Toru
authors: T
authors: Hiraga
authors: Hiroo
authors: H
authors: Miyazawa
authors: Hiroaki
authors: H
authors: Nakamura
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002117:Calcitriol / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects*; D007150:Immunohistochemistry; D008297:Male; D008334:Mandible / Q000166:cytology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects*; D010513:Periodontal Ligament / Q000166:cytology*; D060888:Real-Time Polymerase Chain Reaction; D018167:Receptors, Calcitriol / Q000378:metabolism; D013194:Staining and Labeling
chemical_list: C439889:ASPN protein, human; D015415:Biomarkers; D016326:Extracellular Matrix Proteins; D018167:Receptors, Calcitriol; D000469:Alkaline Phosphatase; D002117:Calcitriol