BMP-2 Induction of Dlx3 Expression Is Mediated by p38/Smad5 Signaling Pathway in Osteoblastic MC3T3-E1 Cells
BMP-2 Induction of Dlx3 Expression Is Mediated by p38/Smad5 Signaling Pathway in Osteoblastic MC3T3-E1 Cells
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DOI：
10.1002/jcp.24525
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发表时间：
2014-07-01
影响因子：
5.6
通讯作者：
Fan, Mingwen
中科院分区：
文献类型：
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作者：
Yang, Guobin;Yuan, Guohua;Fan, Mingwen
DLX3是成骨细胞分化和骨形成所必需的，其表达受骨形态发生蛋白-2(BMP-2)的调节。然而，BMP-2调控成骨细胞DLX3转录的密切机制仍不清楚。考虑到Smad5和p38在成骨细胞分化中的重要作用，我们假设Smad5和p38介导BMP-2诱导成骨细胞DLX3转录。我们发现Smad5和p38的激活增加了DLX3的表达，而Smad5的下调或p38的失活则抑制了BMP-2诱导的DLX3的表达。Smad5和p38均能激活DLX3启动子的活性，p38/Smad5反应元件位于DLX3启动子的-698~-368之间。经EMSA和CHIP鉴定，该区域有两个Smad5结合位点(SBEI和SBEII，TGTCT box)。DLX3启动子区域的缺失和突变研究表明，TGTCT盒对p38/Smad5诱导的DLX3启动子活性至关重要。最后，我们发现p38和Smad5之间存在相互作用，并且p38的激活是BMP-2诱导的Smad5磷酸化和核转位所必需的。总之，我们提出了一个新的观点，即BMP-2诱导的DLX3在成骨细胞中的表达受p38/Smad5信号通路的调控。J.细胞。物理。229：943-954,2014。(C)2013年威利期刊公司。
Dlx3 is essential for osteoblast differentiation and bone formation, and its expression is regulated by bone morphogenetic protein-2 (BMP-2). However, the intimate mechanism of BMP-2 regulation of Dlx3 transcription in osteoblasts is still unknown. Considering the important roles of Smad5 and p38 in osteoblast differentiation, we hypothesized that Smad5 and p38 mediated BMP-2-induced Dlx3 transcription in osteoblasts. We found activation of Smad5 and p38 increased the expression of Dlx3, whereas knocking down Smad5 or inactivation of p38 inhibited BMP-2-induced Dlx3 expression. Both Smad5 and p38 were able to activate Dlx3 promoter activity and p38/Smad5 response elements were located from -698 to -368 in Dlx3 promoter. Two Smad5 binding sites (SBEI and SBEII, TGTCT box) were identified in this region by EMSA and ChIP assay. Deletions and mutagenesis study of the Dlx3 promoter region indicated that the TGTCT boxes are crucial for p38/Smad5-induced Dlx3 promoter activity. At last, we found a cross-talk between p38 and Smad5, and that activation of p38 is necessary for BMP-2-induced Smad5 phosphorylation and nuclear translocation. Overall, we provide a novel insight that BMP-2-induced Dlx3 expression is regulated by p38/Smad5 signaling pathway in osteoblasts. J. Cell. Physiol. 229: 943-954, 2014. (c) 2013 Wiley Periodicals, Inc.