Impact of shear stress and simulated microgravity on osteocytes using a new rotation cell culture device
Impact of shear stress and simulated microgravity on osteocytes using a new rotation cell culture device
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使用新型旋转细胞培养装置研究剪切应力和模拟微重力对骨细胞的影响
DOI：
10.1016/j.actaastro.2015.07.020
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发表时间：
2015-11
影响因子：
3.5
通讯作者：
Fan Yu-Bo
中科院分区：
文献类型：
--
作者：
Yang Xiao;Sun Lian-Wen;Wu Xin-Tong;Liang Meng;Fan Yu-Bo
骨细胞感知机械负荷和失重，并通过指导成骨细胞和破骨细胞的功能来协调骨重建。以往的研究主要集中在机械载荷或微重力对骨细胞自身变化的影响。然而，作为力学传感器，研究失重对骨细胞力学敏感性的影响及其机制更有意义，因为力学敏感性的改变可能进一步影响骨细胞的力学信号转导过程，最终改变骨重建过程。为了研究骨细胞在失重状态下对剪切力的反应，本研究设计了一种新型的模拟微重力和加载流体流动的装置，同时对骨细胞进行体外模拟。在15 dyn/cm 2剪切力和15 rpm转速下，对骨细胞样细胞系MLO-Y 4进行加载。有两个负载持续时间为不同的测定：30分钟的负载检测一氧化氮和前列腺素E2，和6小时的负载检测三个骨形成生物标志物（碱性磷酸酶，骨钙素和前胶原I型N前肽）。为了初步探讨骨细胞对不同重力机械负荷反应的机制，我们还观察了6 h后骨细胞骨架的变化，并对Wnt/β-catenin信号通路中的元件进行了测定。结果表明：（1）在15-30 min的剪切应力作用下，模拟微重力条件下，NO和PGE 2的机械反应性均高于正常重力条件下;（2）模拟微重力条件下，ALP活性的机械反应性降低，OC和PINP含量的机械反应性升高。此外，ALP活性和OC含量与Wnt信号通路的活性相关，Wnt信号通路在骨形成的调控中起关键作用;（3）对骨细胞力学生物反应改变机制的探讨表明，模拟微重力条件下，剪切应力对F-actin纤维的增强作用不如正常重力条件下强，而在细胞周围的短树突状突起仅在模拟微重力组内观察到;（4）此外，模拟微重力显著抑制Wnt/β-结果表明，模拟微重力可改变骨细胞的力学敏感性，这可能是对成骨细胞骨形成的不利影响，而对破骨细胞生成有利。本研究的结果可能为寻找一种有效的方法来防止骨细胞在微重力下改变骨重建的协调性提供重要线索，并且这种预防可能最终使体育锻炼能够抵抗微重力下的骨丢失。
Osteocytes sense the mechanical loading and weightlessness, and orchestrate bone remodeling by directing both osteoblast and osteoclast functions. Previous studies mostly focused on the impact of mechanical loading or microgravity on the osteocyte changes in themselves. However as the mechanosensors, it is more meaningful to make clear whether and how the mechanosensitivity of osteocytes affected by weightlessness, since the alteration of mechanosensitivity may further affect the mechanotransduction process in osteocytes, and finally altered the bone remodeling process. Whereas until now, this aspect had long been overlooked and was still not clear yet.To investigate how osteocytes respond to shear stress under weightlessness, a novel custom-made device was designed to simulate microgravity and load fluid flow on cells in vitro at the same time. The osteocyte-like cell line MLO-Y4 was loaded by this novel device at 15 dyn/cm2shear stress with 15 rpm rotating speed. There were two loading durations for different determinations: 30 min of loading for the detection of nitric oxide and Prostaglandin E2, and 6 h of loading for the detection of three bone formation biomarkers (alkaline phosphatase, osteocalcin and procollagen type I N propeptide). In order to preliminarily explore the mechanism of this altered response to mechanical loading with different gravity in osteocytes, an observation of cytoskeleton and the determination of the elements in the Wnt/β-catenin signaling pathway were also performed after 6 h of loading. The results showed that (1) the mechanical response of both NO and PGE2 were increased higher during 15–30 min of shear stress under simulated microgravity than that under normal gravity; (2) the mechanical response of ALP activity was decreased, while that of OC and PINP content were increased by simulated microgravity. Moreover, the ALP activity and the OC content were related to the activity of Wnt signaling pathway, which plays a key role in regulating the bone formation; (3) the exploration for the mechanism of altered mechanical bio-response in osteocytes showed that F-actin filaments enhanced by shear stress under simulated microgravity were not so robust as that showed under normal gravity, and some short dendritic processes at cell periphery were only observed within the simulated microgravity groups; (4) further, the simulated microgravity significantly inhibited the mechanosensitivity of the Wnt/β-catenin signaling pathway on protein level in the osteocytes.These results suggested that the mechanosensitivity of osteocytes was altered by simulated microgravity, and this may be an adverse effect on the osteoblastic bone formation whereas be good for osteoclastogenesis. The findings in this study may provide an important clue for searching an efficient approach to prevent osteocytes from changing the orchestration for bone remodeling under microgravity, and further this prevention may finally make the physical exercises capable against bone loss under microgravity.
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影响因子：
4
作者：
Santos, A.;Bakker, A. D.;Klein-Nulend, J.
通讯作者：
Klein-Nulend, J.
DOI：
10.1084/jem.20031454
发表时间：
2004-03-15
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
van Bezooijen RL;Roelen BA;Visser A;van der Wee-Pals L;de Wilt E;Karperien M;Hamersma H;Papapoulos SE;ten Dijke P;Löwik CW
通讯作者：
Löwik CW
DOI：
10.1016/j.bbrc.2008.03.007
发表时间：
2008-05-16
影响因子：
3.1
作者：
Tan, S. D.;Bakker, A. D.;Klein-Nulend, J.
通讯作者：
Klein-Nulend, J.
DOI：
10.1038/bonekey.2012.192
发表时间：
2012-10
期刊：
BoneKEy osteovision
影响因子：
--
作者：
Sarah H. McBride;Matthew J. Silva
通讯作者：
Sarah H. McBride;Matthew J. Silva
影响因子：
--
作者：
J. Patton;D. Menter;D. Benson;G. Nicolson;L. McIntire
通讯作者：
J. Patton;D. Menter;D. Benson;G. Nicolson;L. McIntire