Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive Gs-G protein signaling in osteoblasts.
Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive Gs-G protein signaling in osteoblasts.
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DOI：
10.1016/j.yexcr.2015.02.009
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发表时间：
2015-05-01
影响因子：
3.7
通讯作者：
Nissenson RA
中科院分区：
文献类型：
--
作者：
Wattanachanya L;Wang L;Millard SM;Lu WD;O'Carroll D;Hsiao EC;Conklin BR;Nissenson RA
成骨细胞 (OB) 中的 G 蛋白偶联受体 (GPCR) 信号传导是骨形成的重要调节因子。我们之前描述了表达 Rs1 的小鼠模型，Rs1 是一种工程组成型活性 Gs 偶联 GPCR，受 2.3 kb Col I 启动子控制。这些小鼠的股骨小梁表现出与年龄相关的显着增加。在这里，我们通过检查 1 周和 9 周龄 Col1(2.3)/Rs1 小鼠的颅骨，进一步评估了 OB 中增强的 Gs 信号传导对膜内骨形成的影响，并在细胞水平而不是在整个骨骼中表征了具有激活的 Gs G 蛋白偶联受体信号传导的成骨细胞中特异发生的体内基因表达。 Rs1 颅骨骨量显着增加，同时皮质结构部分丧失。通过免疫组织化学，在整个小梁间隙的细胞中检测到 Osterix，而骨钙素主要在骨表面的细胞中表达，这表明由 2.3-kb Col I 启动子驱动的 OB 分泌的旁分泌介质的作用可能影响早期 OB 定型、分化和/或增殖。颅骨 OB 的基因表达分析表明，受 Rs1 信号传导影响的基因包括那些编码对细胞分化、细胞因子和生长因子、血管生成、凝血和能量代谢重要的蛋白质的基因。还确定了可能有助于观察到的骨骼表型的 Gs-GPCR 和其他 GPCR 组以及 OB 中 Gs 信号传导作用的候选旁分泌介质。我们的结果确定了成熟 OB 中骨骼对 Gs 信号传导的合成代谢反应的新的详细体内细胞变化。
G protein–coupled receptor (GPCR) signaling in osteoblasts (OBs) is an important regulator of bone formation. We previously described a mouse model expressing Rs1, an engineered constitutively active Gs-coupled GPCR, under the control of the 2.3-kb Col I promoter. These mice showed a dramatic age-dependent increase in trabecular bone of femurs. Here, we further evaluated the effects of enhanced Gs signaling in OBs on intramembranous bone formation by examining calvariae of 1- and 9-week-old Col1(2.3)/Rs1 mice and characterized the in vivo gene expression specifically occurring in osteoblasts with activated Gs G protein–coupled receptor signaling, at the cellular level rather than in a whole bone. Rs1 calvariae displayed a dramatic increase in bone volume with partial loss of cortical structure. By immunohistochemistry, Osterix was detected in cells throughout the inter-trabecular space while Osteocalcin was expressed predominantly in cells along bone surfaces, suggesting the role of paracrine mediators secreted from OBs driven by 2.3-kb Col I promoter could influence early OB commitment, differentiation, and/or proliferation. Gene expression analysis of calvarial OBs revealed that genes affected by Rs1 signaling include those encoding proteins important for cell differentiation, cytokines and growth factors, angiogenesis, coagulation, and energy metabolism. The set of Gs-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of Gs signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to Gs signaling in mature OBs.