title: Vitamin D3 supports osteoclastogenesis via functional vitamin D response element of human RANKL gene promoter.
abstract: Receptor activator of NF-kappaB ligand (RANKL) has been identified as requisite for osteoclastogenesis. To elucidate the molecular mechanism that conducts its catabolic action on bone, the effect of 1alpha,25 dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) on osteoclastogenesis and RANKL mRNA expression was examined by coculture, RT-PCR and nuclear run-on studies. By accelerating the transcription rate of the RANKL gene in SaOS2 osteoblastic cells, 1alpha,25(OH)(2)D(3) enhanced in vitro osteoclast formation from peripheral monocytes. Cloning and characterization of the 5'-flanking region of the human RANKL gene revealed that the basic promoter comprises inverted TATA- and CAAT-boxes flanked by RUNX2 binding sites. Both electrophoresis mobility shift assay (EMSA) and transfection studies demonstrated that 1alpha,25(OH)(2)D(3) activated human RANKL promoter through vitamin D responsive elements (VDRE) located at -1584/-1570 by binding VDR and RXRalpha heterodimers in a ligand-dependent manner. The results provide direct evidence that 1alpha,25(OH)(2)D(3) augments osteoclastogenesis by transactivating the human RANKL gene in osteoblastic cells through VDRE.
authors.affiliation: Division of Molecular Pathology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Sohei
authors.initials: S
authors.lastname: Kitazawa
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kajimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondo
authors.forename: Riko
authors.initials: R
authors.lastname: Kitazawa
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002762:Cholecalciferol / Q000494:pharmacology*; D003001:Cloning, Molecular; D018920:Coculture Techniques; D050659:Core Binding Factor Alpha 1 Subunit; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects*; D011401:Promoter Regions, Genetic; D053245:RANK Ligand; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D053246:Receptor Activator of Nuclear Factor-kappa B; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured; D030181:Vitamin D Response Element / Q000502:physiology*
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; C505686:TNFRSF11A protein, human; C505688:TNFSF11 protein, human; D014157:Transcription Factors; D002762:Cholecalciferol