Investigation of action of shear stress, which is produced by Mechanical loading applied to the skeleton, on osteodast formation and bone-resorbing activity

研究由施加到骨骼的机械载荷产生的剪切应力对破骨细胞形成和骨吸收活性的作用

• 批准号: 17591922
• 负责人: HAKEDA Yoshiyuki
• 金额: $ 2.24万
• 依托单位: Meikai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17591922/
• 关键词: bone; fluid shear stress; osteoblasts; osteoclastogenesis; bone resorption; RANKL; prostaglandin; OPG; 破骨細胞文化

Background : Mechanical loading applied to the skeleton is crucial to the development and maintenance of bone integrity and architecture. A decrease in the mechanical loading due to prolonged immobilization or weightlessness in space reduces the bone formation rate, resulting in bone loss. On the other hand, an increase in mechanical loading causes a gain in bone density. Thus, bone tissue is sensitive to mechanical stimulation. Mechanical loading on bone generates extracellular matrix deformation and fluid flow, and the mechanical stimuli are translated to mechanical signals such as mechanical strain and fluid shear stress, respectively. Evidence obtained from in vitro studies indicates that osteocytes embedded in the lacunae/canaliculi system and osteoblasts and bone cells lining the bone surface are mechanosensors that detect load-derived mechanical stimuli. By these bone-forming cells, the mechanical stimuli are translated into cellular signaling factors. However, normal bone metab … More olism is achieved by bone remodeling on balance between bone-forming cells and bone-resorbing cells. To date, the effect of fluid shear stress on osteoblasts has been extensively investigated ; however, the action on osteoclasts responsible for bone resorption remains to be elucidated. Therefore, the aim of this study is to elucidate the effect of fluid shear stress on osteoclastogenesis and osteoclast function directly or indirectly via osteoblasts.Methods : We isolated osteoblastic cells from mouse calvaria, and loaded fluid shear stress on these cells with a single flow-through system. In the case of study on osteoclast formation, we employed in vitro culture system of M-CSF dependent bone marrow cells-derived osteoclast progenitors for osteoclast formation dependent on RANKL. Results and Discussion : Isolated mouse calvalia-derived osteoblasts were capable of forming nodules and calcifing in a long-term culture. When the osteoblasts were exposed to fluid shear stress, expression of Cox-2 and RANKL mRNAs was increased as early as 2h after the start of exposure. In addition, gene expression of OPG, a soluble decoy receptor of RANKL, was also increased by the fluid shear stress in the cells ; however, the increase was less than that of RANKL expression. Conditioned medium obtained from the culture of shear stress-loading osteoblasts increased osteoclast formation induced by low concentration of RANKL, whereas the conditioned medium from the stress-unloading osteoblasts did not stimulated the formation. Short-term shear stress loading was sufficient for induction of RANKL gene expression, and the induction maintained even after freeing the loading. The shear stress-induced RANKL expression was dependent on the activation of Erk, but independent of prostaglangin induced by the shear stress. Finally, fluid shear stress directly stimulated the osteoclast formation from osteoclast precursors that were treated with M-CSF and low doses of RANKL. Taken together, fluid shear stress stimulates osteoclastogenesis directly or indirectly via inducing RANKL expression in osteoblasts. Less

背景：应用于骨骼的机械载荷对于骨完整性和建筑的发展和维护至关重要。由于长时间的固定或空间失重而导致的机械负荷减少会降低骨骼形成率，从而导致骨质流失。另一方面，机械负载的增加会导致骨密度增长。那就是骨组织对机械刺激敏感。骨上的机械负荷会产生细胞外基质变形和流体流动，并分别将机械刺激转化为机械信号，例如机械应变和流体剪切应力。从体外研究获得的证据表明，嵌入在空白/关节系统中的骨细胞和骨表面衬里的骨细胞和骨细胞是检测负载衍生的机械刺激的机械力学。通过这些骨形成细胞，机械刺激被转化为细胞信号传导因子。但是，正常的骨代谢…通过在骨形成细胞和骨折细胞之间平衡骨骼来实现更多的遗传。迄今为止，已经广泛研究了液体剪应力对成骨细胞的影响。但是，尚待阐明负责骨骼分辨率的破骨细胞的作用。因此，这项研究的目的是阐明流体剪切应力对骨质塑料发生的影响，而破骨细胞的作用直接或间接通过破骨细胞。在研究破骨细胞形成的研究中，我们采用了M-CSF依赖性骨髓细胞衍生的破骨细胞祖细胞的体外培养系统，用于取决于RANKL的破骨细胞形成。结果与讨论：孤立的小鼠calvalia衍生的成骨细胞能够形成结节并在长期培养中钙化。当成骨细胞暴露于流体剪切应力时，在接触开始后2H时，COX-2和RANKL mRNA的表达早在2H时就增加。另外，细胞中的液体剪切应力也增加了RANKL的固体诱饵受体OPG的基因表达。但是，增加小于RANKL表达的增加。从剪切应力载荷成骨细胞培养的条件培养基增加了由低浓度的RANKL诱导的破骨细胞形成，而来自压力不载的成骨细胞的条件培养基并没有刺激形成。短期剪切应力载荷足以诱导RANKL基因表达，即使在释放了载荷后，诱导也能保持诱导。剪切应力诱导的RANKL表达取决于ERK的激活，但与剪切应力诱导的前列腺素无关。最后，流体剪切应力直接刺激了用M-CSF和低剂量RANKL处理的破骨细胞前体的破骨细胞形成。综上所述，流体剪切应力通过成骨细胞中的RANKL表达直接或间接刺激破骨细胞生成。较少的

项目成果

グルココルチコイドの骨形成系・骨吸収系細胞に対する作用

糖皮质激素对成骨细胞和骨吸收细胞的影响

• 发表时间: 2006
• 期刊: Cinical Calcium 16
• 作者: Nakamura;T.;Arai;Y.;Umehara;H.;Masuhara;M.;Kimura;T.;Taniguchi;H.;Sekimoto;T.;Ikawa;M.;Yoneda;Y.;Okabe;M.;Tanaka;S.;Shiota;K.;Nakano;T.;羽毛田慈之
• 通讯作者: 羽毛田慈之

Action of glucocorticoid on bone-forming and bone-resorbing cells.

糖皮质激素对骨形成和骨吸收细胞的作用。

• 发表时间: 2006
• 期刊: Clin Calcium 16(11)
• 作者: Nakamura;T.;Arai;Y.;Umehara;H.;Masuhara;M.;Kimura;T.;Taniguchi;H.;Sekimoto;T.;Ikawa;M.;Yoneda;Y.;Okabe;M.;Tanaka;S.;Shiota;K.;Nakano;T.;羽毛田慈之;Ozaki A;Hakeda Y.
• 通讯作者: Hakeda Y.