Li Ping, Liu Chenglin, Hu Man, Long Mian, Zhang Ding, Huo Bo
Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, People's Republic of China.
Ann Biomed Eng. 2014 Jun;42(6):1250-60. doi: 10.1007/s10439-014-0984-x. Epub 2014 Apr 8.
Intracellular calcium oscillation and its downstream signaling in osteoclasts is believed to play critical roles in regulating bone resorption. Our previous study demonstrated that fluid shear stress (FSS) induced more calcium responsive peaks in the late differentiated osteoclasts than the early ones. In this paper, the signaling pathways of FSS-induced calcium response for the osteoclasts in different differentiation stages were studied. RAW264.7 macrophage cells were induced to differentiate into osteoclasts with the conditioned medium from MC3T3-E1 osteoblasts. Furthermore pharmacological agents were added to block the specific signaling pathways. Finally the cells were exposed to FSS at different levels (1 or 10 dyne/cm(2)) after being induced for 4 or 8 days. The results showed that the mechanosensitive, cation-selective channels, phospholipase C (PLC) and endoplasmic reticulum constituted the major signaling pathway for mechanical stimulation-induced calcium response in osteoclasts. Extracellular calcium or ATP involved with calcium oscillation in a FSS magnitude-dependent manner. This pathway study may help to give insight into the molecular mechanism of mechanical stimulation-regulated bone remodeling.
破骨细胞内的钙振荡及其下游信号传导被认为在调节骨吸收中起关键作用。我们之前的研究表明，流体剪切力（FSS）在晚期分化的破骨细胞中比早期分化的破骨细胞诱导出更多的钙反应峰。本文研究了不同分化阶段破骨细胞中FSS诱导钙反应的信号通路。用MC3T3-E1成骨细胞的条件培养基诱导RAW264.7巨噬细胞分化为破骨细胞。此外，添加药物试剂阻断特定的信号通路。最后，在诱导4天或8天后，将细胞暴露于不同水平（1或10达因/平方厘米）的FSS。结果表明，机械敏感的阳离子选择性通道、磷脂酶C（PLC）和内质网构成了破骨细胞中机械刺激诱导钙反应的主要信号通路。细胞外钙或ATP以FSS强度依赖的方式参与钙振荡。该信号通路研究可能有助于深入了解机械刺激调节骨重塑的分子机制。
