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Cell Death and Disease文章:Runx2参与调控成骨分化的机制

成骨细胞分化是骨形成的关键事件,Runt-related transcription factor-2 (Runx2) 是成骨分化必需的一个因素。然而,Runx2调控成骨分化的机制还不清楚。本研究使用C2C12/Runx2(Dox)研究了Runx2表达响应doxycycline (Dox)的机制,发现Runx2诱导的C2C12细胞成骨分化导致HB-EGF(真皮细胞生长因子)表达水平的降低,HB-EGF强制表达或者用HB-EGF处理能够减少alkaline phosphatase (ALP)表达。Runx2 特异结合到 Hbegf 启动子区,意味着Hbegf 转录直接被Runx2抑制。Runx2 可以上调 miR-1192, 增加 Runx2诱导的成骨分化。而且,miR-1192通过翻译抑制直接与Hbegf靶基因结合,表明miR-1192通过下调HB-EGF,增加Runx2诱导的成骨分化,总之,研究结果表明,Runx2通过转录和转录后的机制下调HB-EGF使HB-EGF-EGFR信号失活,从而诱导C2C12细胞的成骨分化。本研究采用的Affymetrix GeneChip mouse genome 430 2.0 array芯片的检测服务博奥生物集团有限公司完成。本研究于2013年发表在Cell Death and Disease杂志上(影响因子:6.044)。


原文摘要:
Heparin-binding EGF-like growth factor and miR-1192 exert opposite effect on Runx2-induced osteogenic differentiation
Osteoblast differentiation is a pivotal event in bone formation. Runt-related transcription factor-2 (Runx2) is an essential factor required for osteoblastdifferentiation and bone formation. However, the underlying mechanism of Runx2-regulated osteogenic differentiation is still unclear. Here, we explored the corresponding mechanism using the C2C12/Runx2(Dox) subline, which expresses Runx2 in response to doxycycline (Dox). We found thatRunx2-induced osteogenic differentiation of C2C12 cells results in a sustained decrease in the expression of heparin-binding EGF-like growth factor(HB-EGF), a member of the epidermal growth factor (EGF) family. Forced expression of HB-EGF or treatment with HB-EGF is capable of reducing the expression of alkaline phosphatase (ALP), a defined marker of early osteoblast differentiation. HB-EGF-mediated inhibition of ALP depends upon activation of the EGFR and the downstream extracellular signal-regulated kinase, c-Jun N-terminal kinase mitogen-activated protein kinase pathways as well as phosphatidylinositol 3-kinase/Akt pathway. Runx2 specifically binds to the Hbegf promoter, suggesting that Hbegf transcription is directly inhibited by Runx2. Runx2 can upregulate miR-1192, which enhances Runx2-induced  osteogenic  differentiation. Moreover, miR-1192 directly targets Hbegf through translational inhibition, suggesting enhancement of Runx2-induced osteogenic differentiation by miR-1192 through the downregulation of HB-EGF. Taken together, our results suggest that Runx2 induces osteogenic differentiation of C2C12 cells by inactivating HB-EGF-EGFR signaling through the downregulation of HB-EGF via both transcriptional and post-transcriptional mechanisms.
原文出处:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3824672/