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Vitamin D 3 supports osteoclastogenesis via functional vitamin D response element of human RANKL gene promoter
Author(s) -
Kitazawa Sohei,
Kajimoto Kazuyoshi,
Kondo Takeshi,
Kitazawa Riko
Publication year - 2003
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10567
Subject(s) - rankl , calcitriol receptor , microbiology and biotechnology , activator (genetics) , chemistry , osteoclast , transfection , runx2 , vitamin d and neurology , transcription factor , receptor , biology , gene , endocrinology , biochemistry
Receptor activator of NF‐κB ligand (RANKL) has been identified as requisite for osteoclastogenesis. To elucidate the molecular mechanism that conducts its catabolic action on bone, the effect of 1α,25 dihydroxyvitamin D 3 (1α,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, 1α,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 1α,25(OH) 2 D 3 activated human RANKL promoter through vitamin D responsive elements (VDRE) located at −1584/−1570 by binding VDR and RXRα heterodimers in a ligand‐dependent manner. The results provide direct evidence that 1α,25(OH) 2 D 3 augments osteoclastogenesis by transactivating the human RANKL gene in osteoblastic cells through VDRE. J. Cell. Biochem. 89: 771–777, 2003. © 2003 Wiley‐Liss, Inc.