REGULATION OF BONE FORMATION BY OSTEOCLASTS

骨吸收和骨形成似乎是紧密耦合的。探讨破骨细胞对骨质疏松症的影响 成骨细胞的募集和分化，我们检测了破骨细胞条件培养液(CM)对 成骨细胞。破骨细胞CM刺激人骨髓间充质干细胞形成矿化结节。 我们使用Affymetrix微阵列确定了候选的破骨细胞来源的偶联因子。我们观察到 成熟多核破骨细胞SPHK1、WntlOb和Bmp6的诱导 与破骨前细胞相比。破骨细胞CM对HMS细胞结节形成的刺激作用减弱 通过Wnt拮抗剂Dkk1、BMP-6中和抗体Dkk1和S1P拮抗剂。硬化素的表达 在破骨细胞前体细胞中表达升高，在分化过程中迅速下调。破骨细胞来源的cm 18月龄小鼠体外产生的HMS细胞不能支持HMS细胞矿化。转化生长因子-β 治疗可上调SPHK1和WntlOb的表达。我们的中心假设是破骨细胞产生的 SPHK1、WntlOb和Bmp6结合skerostin表达降低促进成骨细胞 前体的招募、增殖、分化和存活，每个因素在 维持破骨细胞介导骨吸收和成骨细胞介导骨形成之间的偶联。 在目标1中，我们将使用功能细胞分析和基因表达来确定 破骨细胞衍生偶联因子促进成骨细胞基因表达、募集、增殖 分化，并在体外存活。在目标2中，我们将使用分子方法来确定机制。 在体外破骨细胞分化过程中，硬化素、SPHK1、WntlOb和Bmp6被调控。在……里面 目的3我们将使用体内模型来研究转化生长因子-β对偶联因子产生的调节作用。 破骨细胞介导的骨吸收与骨形成的偶联。在目标4中，我们将检测基因 AGE在破骨细胞支持成骨细胞中的表达和细胞分析 成熟化和矿化。总之，这些研究将提供重要的新信息，说明如何 破骨细胞控制成骨细胞介导的骨形成。

Bone resorption and bone formation appear to be tightly coupled. To explore osteoclast influences on osteoblast recruitment and differentiation, we examined osteoclast conditioned media (CM) for influences on osteoblasts. Osteoclast CM stimulated human mesenchymal stem (hMS) cell mineralized nodule formation. We identified candidate osteoclast-derived coupling factors using Affymetrix microarray. We observed induction of sphingosine kinase 1 (SPHK1), WntlOb, and BMP6 in mature multinucleated osteoclasts as compared to pre-osteoclasts. Stimulation of hMS cell nodule formation by the osteoclast CM was attenuated by the Wnt antagonist, Dkk1, a BMP-6 neutralizing antibody, and by a S1P antagonist. Sclerostin expression was elevated in osteoclast precursors and rapidly down-regulated during differentiation. CM from osteoclasts generated in vitro from 18-month old mice was unable to support hMS cell mineralization. TGF-beta treatment elevated SPHK1 and WntlOb expression. Our central hypothesis is that osteoclast production of SPHK1, WntlOb, and BMP6, combined with decreased Sclerostin expression, promotes osteoblast precursor recruitment, proliferation, differentiation, and survival and that each factor plays an integral role in maintaining coupling between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. In Aim 1, we will use functional cell assays and gene expression to ascertain the mechanisms by which osteoclast-derived coupling factors promote osteoblast gene expression, recruitment, proliferation, differentiation, and survival in vitro. In Aim 2 we will use molecular approaches to determine the mechanisms by which Sclerostin, SPHK1, WntlOb, and BMP6 are modulated during osteoclast differentiation in vitro. In Aim 3 we will use an in vivo model to examine the role of TGF-beta regulation of coupling factor production on osteoclast-mediated coupling of bone resorption to bone formation. In Aim 4 we will examine gene expression and cellular assays to resolve the contribution of age in osteoclast support of osteoblast maturation and mineralization. Together, these studies will provide important novel information on how osteoclasts control osteoblast-mediated bone formation.