Helix-loop-helix-type transcription factor (HES-1) is expressed in osteoblastic cells, suppressed by 1,25(OH)2 vitamin D3, and modulates 1,25(OH)2 vitamin D3 enhancement of osteopontin gene expression.
The active form of vitamin D, 1,25(OH)2 vitamin D3 (D3), is a potent modulator of osteoblastic function. In this study, we examined, the expression of a negative-type basic helix-loop-helix transcription factor, HES-1, in osteoblastic cells and the regulation of its expression by D3. We found that HES-1 is expressed as a 1.7 kb mRNA in rat osteoblastic osteosarcoma ROS17/2.8 cells. Treatment with D3 suppressed HES-1 mRNA levels by about 50%. This suppression was observed within 24 h and lasted for at least 48 h. The suppressive effect was dose-dependent starting at 10(-9) mol/L and saturated at 10(-8) mol/L. The vitamin D3 suppression of HES-1 mRNA level was blocked by actinomycin D as well as cycloheximide, suggesting the involvement of transcriptional control, which requires new protein synthesis. Proteins in the crude nuclear extracts prepared from ROS17/2.8 cells bound to the N-box sequence (CACNAG). To examine the function of HES-1 in osteoblasts, HES-1 was overexpressed in ROS17/2.8 cells. Overexpression of HES-1 suppressed the vitamin D-dependent upregulation of osteopontin gene expression in these cells. Vitamin D suppression of HES-1 gene expression was also observed in normal rat calvaria-derived osteoblast-enriched cells. These results indicate that HES-1 is expressed in osteoblastic cells and is involved in vitamin D3 regulation of osteoblastic gene expression.
Matsue
M
M
Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Chiyoda-Ku, Japan.
Kageyama
R
R
Denhardt
D T
DT
Noda
M
M
D000818:Animals; D015152:Blotting, Northern; D001859:Bone Neoplasms / Q000235:genetics / Q000473:pathology; D002117:Calcitriol / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D003513:Cycloheximide / Q000633:toxicity; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000235:genetics*; D003609:Dactinomycin / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects* / Q000235:genetics; D018257:Helix-Loop-Helix Motifs / Q000235:genetics*; D019384:Nucleic Acid Synthesis Inhibitors / Q000633:toxicity; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D053495:Osteopontin; D012516:Osteosarcoma / Q000235:genetics / Q000473:pathology; D011500:Protein Synthesis Inhibitors / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012795:Sialoglycoproteins / Q000096:biosynthesis / Q000235:genetics*; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
D004268:DNA-Binding Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D051820:TCF Transcription Factors; C553060:Tcf7l1 protein, rat; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D053495:Osteopontin; D003609:Dactinomycin; D003513:Cycloheximide; D002117:Calcitriol