| RRC ID |
39842
|
| 著者 |
Kurokouchi K, Kambe F, Kikumori T, Sakai T, Sarkar D, Ishiguro N, Iwata H, Seo H.
|
| タイトル |
Effects of glucocorticoids on tumor necrosis factor alpha-dependent activation of nuclear factor kappaB and expression of the intercellular adhesion molecule 1 gene in osteoblast-like ROS17/2.8 cells.
|
| ジャーナル |
J Bone Miner Res
|
| Abstract |
Recently, we showed that tumor necrosis factor alpha (TNF-alpha) stimulates expression of the intercellular adhesion molecule 1 (ICAM-1) and interleukin-6 (IL-6) genes through activation of p65-p50 heterodimer nuclear factor KB (NF-kappaB) in rat osteoblast-like ROS17/2.8 cells. In the present study, we investigated effects of a synthetic glucocorticoid, dexamethasone (Dex), on TNF-alpha-dependent activation of NF-kappaB and expression of the ICAM-1 gene. ROS17/2.8 cells were pretreated with Dex for 6 h and then exposed to TNF-alpha. Electrophoretic mobility shift assay (EMSA) revealed that TNF-alpha-dependent activation of NF-kappaB was almost completely suppressed by Dex treatment. Increase in ICAM-1 messenger RNA (mRNA) level by TNF-alpha also was markedly suppressed by Dex. Western blot and immunocytochemical analyses showed that Dex attenuated the TNF-alpha-induced nuclear translocation of p65. Treatment with protein synthesis inhibitor cycloheximide (CHX) reversed the Dex effect, indicating that Dex requires de novo protein synthesis for its action. Northern blot analysis revealed that Dex increased IkappaB-alpha mRNA level synergistically with TNF-alpha, whereas it decreased p65 mRNA level. The p105 and IkappaB-beta mRNA levels were not altered by Dex. Consistent with the mRNA level, Dex increased the amount of IkappaB-alpha protein in the cytoplasm in either the presence or the absence of TNF-alpha. Considering a role of IkappaB to sequester NF-kappaB in the cytoplasm, it was suggested that an increase in IkappaB-alpha protein and the concomitant decrease in p65 synthesis account for the Dex-induced suppression of NF-kappaB activation in osteoblastic cells.
|
| 巻・号 |
15(9)
|
| ページ |
1707-15
|
| 公開日 |
2000-9-1
|
| DOI |
10.1359/jbmr.2000.15.9.1707
|
| PMID |
10976991
|
| MeSH |
Animals
Cell Line
Cycloheximide / pharmacology
DNA / genetics
DNA / metabolism
DNA-Binding Proteins / biosynthesis
DNA-Binding Proteins / genetics
Dexamethasone / pharmacology*
Dimerization
Gene Expression Regulation / drug effects*
Humans
I-kappa B Proteins*
Immunohistochemistry
Intercellular Adhesion Molecule-1 / genetics*
Intercellular Adhesion Molecule-1 / metabolism
NF-KappaB Inhibitor alpha
NF-kappa B / genetics
NF-kappa B / metabolism*
NF-kappa B p50 Subunit
Nuclear Proteins / metabolism
Osteoblasts / drug effects*
Osteoblasts / metabolism
Protein Precursors / genetics
Protein Transport / drug effects
RNA, Messenger / genetics
RNA, Messenger / metabolism
Rats
Transcription Factor RelA
Tumor Necrosis Factor-alpha / pharmacology*
|
| IF |
5.854
|
| 引用数 |
14
|
|
WOS 分野
|
ENDOCRINOLOGY & METABOLISM
|
| リソース情報 |
| ヒト・動物細胞 |
ROS-17/2.8-5(RCB0462) |
