- 作者: Shuang Yang; Li Zhao; Juhua Yang; Dinggeng Chai; Ming Zhang; Jie Zhang; Xiaohui Ji; Tianhui Zhu
- 作者服務機構: 1 Medical College of Nankai University, 94 Weijin Road, Tianjin 300071, China; ; 2 Skeletal and Inflammatory Diseases, Procter and Gamble Pharmaceuticals, Mason, USA
- 中文摘要: --
- 英文摘要: Osteoblasts, derived from pluripotent mesenchymal precursor cells, acquire their differentiated phenotypes under the control of a series of regulatory factors, the best known of which is BMP-2. Our recent preliminary studies suggest that expression of δEF1, a member of the zinc finger-homeodomain transcription factor family, is significantly down-regulated as human mesenchymal stem cells (MSCs) are subjected to osteoblastic differentiation in the presence of BMP-2. Here we demonstrate that overexpression of δEF1 in murine pre-myoblast C2C12 cells resulted in a decrease in the mRNA levels of early osteoblast marker genes induced by BMP-2 including osterix and collagen type I. This inhibitory effect was further confirmed by decreased alkaline phosphatase (ALP) activities. Neither of the zinc finger clusters of δEF1 is necessary for its repressive effect on BMP-2-induced osteoblastic differentiation of C2C12 cells. Immunoprecipitation results indicated that δEF1 did not physically associate with Smads proteins, suggesting that the inhibitory effect of δEF1 may be Smad-independent. δEF1 overexpression in C2C12 cells resulted in down-regulation of activating protein-1 (AP-1) activities promoted by BMP-2. Moreover, δEF1 exhibited transrepression on murine osteocalcin gene which effect is partially mediated through diminishing of AP-1 signaling. These results suggest that δEF1 acts as a potent inhibitor of BMP-2-induced osteogenesis in vitro, in part, by differentially regulating the AP-1 signaling pathway.
- 中文關鍵字: --
- 英文關鍵字: AP-1, BMP-2, δEF1, N- and C-terminal zinc-finger clusters, osteoblast differentiation