Pérez-Campo Flor M, Santurtún Ana, García-Ibarbia Carmen, Pascual María A, Valero Carmen, Garcés Carlos, Sañudo Carolina, Zarrabeitia María T, Riancho José A
Faculty of Medicine Department of Molecular Biology, University of Cantabria, Santander, Spain.
Unit of Legal Medicine, Faculty of Medicine, University of Cantabria, Santander, Spain.
Calcif Tissue Int. 2016 Sep;99(3):302-9. doi: 10.1007/s00223-016-0144-4. Epub 2016 May 6.
Sclerostin, encoded by the SOST gene, works as an inhibitor of the Wnt pathway and therefore is an important regulator of bone homeostasis. Due to its potent action as an inhibitor of bone formation, blocking sclerostin activity is the purpose of recently developed anti-osteoporotic treatments. Two bone-specific transcription factors, RUNX2 and OSX, have been shown to interact and co-ordinately regulate the expression of bone-specific genes. Although it has been recently shown that sclerostin is targeted by OSX in mice, there is currently no information of whether this is also the case in human cells. We have identified SP-protein family and AML1 consensus binding sequences at the human SOST promoter and have shown that OSX, together with RUNX2, binds to a specific region close to the transcription start site. Furthermore, we show that OSX and RUNX2 activate SOST expression in a co-ordinated manner in vitro and that SOST expression levels show a significant positive correlation with OSX/RUNX2 expression levels in human bone. We also confirmed previous results showing an association of several SOST/RUNX2 polymorphisms with bone mineral density.
由SOST基因编码的硬化蛋白作为Wnt信号通路的抑制剂,因此是骨稳态的重要调节因子。由于其作为骨形成抑制剂的强大作用,阻断硬化蛋白活性是最近开发的抗骨质疏松治疗的目的。两种骨特异性转录因子RUNX2和OSX已被证明相互作用并协同调节骨特异性基因的表达。尽管最近已表明在小鼠中OSX靶向硬化蛋白,但目前尚无关于人类细胞中是否也是如此的信息。我们在人类SOST启动子上鉴定出SP蛋白家族和AML1共有结合序列,并表明OSX与RUNX2一起结合到靠近转录起始位点的特定区域。此外,我们表明OSX和RUNX2在体外以协同方式激活SOST表达,并且在人类骨骼中SOST表达水平与OSX/RUNX2表达水平呈显著正相关。我们还证实了先前的结果,即几种SOST/RUNX2多态性与骨密度相关。