Analysis of signaling pathways involved in polarization of osteoclasts.

(1)我们以前建立了一个培养系统，用于检查破骨细胞的形成。本研究还利用体外培养的破骨细胞样细胞建立了一种新的骨吸收测定系统。因此，现在有可能在一系列实验中检查各种化合物对破骨细胞的募集和相同破骨细胞的小窝形成的影响。(2)使用OP/OP小鼠源性成骨细胞，我们发现M-CSF不仅是不可缺少的破骨细胞前体细胞的增殖，但也为他们分化成破骨细胞。(3)当破骨细胞被放置在牙本质切片或塑料皿上时，它们形成了环状结构的足状体（肌动蛋白环）。环形结构显示对应于骨吸收破骨细胞的清晰区域。肌动蛋白环的形成和破坏与破骨细胞的成孔活性密切相关。(4)研究表明，由p60 α<c-src>、PI-3激酶、粘着斑激酶和小GTP结合蛋白rho介导的信号通路基本上参与破骨细胞的肌动蛋白环形成。有人提出，降钙素受体耦合到与蛋白激酶A和蛋白激酶C相关的途径。我们研究了破骨细胞样细胞中降钙素作用的信号通路。我们发现，降钙素诱导的细胞骨架的显着变化主要是由蛋白激酶A途径介导的。

(1) We have previously established a culture system for examining osteoclast formation. In the present study, a new resorption assay system was also established using osteoclast-like cells formed in vitro. Therefore, it is now possible to examine the effect of various compounds on the recruitment of osteoclasts and pit formation by the same osteoclasts in a series of experiments.(2) Using op/op mouse-derived osteoblastic cells, we found that M-CSF is indispensable not only for proliferation of osteoclast precursors but also for their differentiation into osteoclasts.(3) When osteoclasts were placed on dentine slices or plastic dishes, they formed the ringed structure of podosomes (actin rings). The ringed structure is shown to correspond to clear zones of bone resorbing osteoclasts. The Formation and disruption of the actin ring were correlated well with pit forming activity of osteoclasts.(4) It was shown that signaling pathways meditated by p60^<c-src>, PI-3 kinase, focal adhesion kinase and small GTP binding protein, rho, are essentially involved in actin ring formation by osteoclasts. It has been proposed that calcitonin receptors are coupled to the pathways associated with both protein kinase A and protein kinase C.We examined the signaling pathway of calcitonin action in osteoclast-like cells. We found that calcitonin-induced dramatic alteration in the cytoskeleton is mainly mediated by the protein kinase A pathway.