title: Inhibition of Runx2 signaling by TNF-α in ST2 murine bone marrow stromal cells undergoing osteogenic differentiation.
abstract: Tumor necrosis factor-alpha (TNF-α) inhibits osteogenic differentiation of murine bone marrow stromal cells, and transcription factor Runx2 serves as an essential regulation target in the process. The underlying mechanism may involve the regulation of Runx2 expression and the Runx2 activity in downstream gene transcription, which has not been fully elucidated. In this study, ST2 murine bone marrow-derived stromal cells were treated with bone morphogenetic protein-2 (BMP-2) and/or TNF-α in osteogenic medium, and the expression of Runx2 was estimated. Cells were transfected with Runx2, p65, inhibitor of κBα (IκBα), 9.0 kb bone sialoprotein (BSP) promoter-luciferase or osteoblast-specific cis-acting element 2 (OSE2)-luciferase reporter vectors, and then real time-PCR and dual luciferase analysis were used to investigate the effect of TNF-α on Runx2-activated osteogenic gene transcription and the molecular mechanism. We found that TNF-α inhibited BMP-2-induced osteogenic marker expression and both the spontaneous and BMP-2-induced Runx2 expression. TNF-α stimulation or overexpression of nuclear factor-kappa B (NF-κB) p65 subunit repressed the Runx2-activated BSP and osteocalcin (OC) transcriptions. The Runx2-induced 9.0 kb BSP promoter activity was attenuated by TNF-α or p65, while the OSE2 activity was not affected. Besides, blockage of NF-κB by IκBα overexpression eliminated these inhibitory effects of TNF-α on Runx2 signaling. These results suggest that in murine bone marrow stromal cells undergoing osteogenic differentiation, TNF-α and it activated NF-κB pathway inhibit the expression of Runx2 gene, and suppress the Runx2-mediated osteogenic gene transcription via the 9.0 kb BSP promoter.
authors.affiliation: School of Stomatology, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province, 250012, China.|Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong University, Jinan, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ye
authors.affiliation: School of Stomatology, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province, 250012, China.|Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong University, Jinan, China.
authors.forename: Haiyun
authors.initials: H
authors.lastname: Huang
authors.affiliation: School of Stomatology, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province, 250012, China.|Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong University, Jinan, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhao
authors.affiliation: School of Stomatology, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province, 250012, China. tendenzj@sdu.edu.cn.|Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong University, Jinan, China. tendenzj@sdu.edu.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Stomatology, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province, 250012, China. yangps@sdu.edu.cn.|Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong University, Jinan, China. yangps@sdu.edu.cn.
authors.forename: Pishan
authors.initials: P
authors.lastname: Yang
mesh_terms: D000818:Animals; D020029:Base Pairing / Q000235:genetics; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D058574:Integrin-Binding Sialoprotein / Q000235:genetics; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D055396:Bone Morphogenetic Protein 2; D050659:Core Binding Factor Alpha 1 Subunit; D058574:Integrin-Binding Sialoprotein; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha
keywords: Bone marrow stromal cells; NF-κB; Osteogenic differentiation; Runx2; Tumor necrosis factor-α