Nuclear factor-kappaB p50 is required for tumor necrosis factor-alpha-induced colony-stimulating factor-1 gene expression in osteoblasts.
Colony-stimulating factor (CSF)-1 is a hematopoietic growth factor that is released by osteoblasts and is recognized to play a critical role in bone remodeling in vivo and in vitro. We have reported that osteoblasts express CSF-1 constitutively and that tumor necrosis factor (TNF)-alpha, a potent bone-resorbing agent, increases CSF-1 gene expression by a transcriptional mechanism. In the present study, we report that an NF-kappaB site in the CSF-1 promoter is required for TNF-alpha-induced CSF-1 expression in osteoblasts. As determined by electrophoretic mobility shift assays, antiserum against the NF-kappaB-binding protein, p50, retarded the mobility of the inducible complex, whereas antisera against p52, p65, c-Rel, Rel B, IkappaB alpha, IkappaB gamma, and Bcl-3 had no effect. To further confirm that p50 is necessary for TNF-alpha-induced CSF-1 expression in osteoblasts, CSF-1 messenger RNA expression from untreated and TNF-alpha-treated osteoblasts, prepared from wild-type and p50 knock-out mice, was examined by Northern analysis. CSF-1 messenger RNA was increased by TNF treatment in wild-type mice but not in NF-kappaB p50 knock-out mice. Our findings support the conclusion that the NF-kappaB subunit p50 is critical for TNF-induced CSF-1 expression in osteoblasts.
The Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8016, USA. gang-qing.yao@yale.edu
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D000818:Animals; D001665:Binding Sites; D015870:Gene Expression; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D010006:Osteoblasts / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D007106:Immune Sera; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor