Round versus flat: Bone cell morphology, elasticity, and mechanosensing
Round versus flat: Bone cell morphology, elasticity, and mechanosensing
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DOI：
10.1016/j.jbiomech.2008.01.031
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Smit, Theo H.
中科院分区：
文献类型：
--
作者：
Bacabac, Rommel G.;Mizuno, Dalsuke;Smit, Theo H.
越来越多的证据表明，细胞功能和力学性能与形态密切相关。然而，大多数体外研究研究扁平贴壁细胞，这可能不反映体内的生理几何形状。骨细胞是骨中的力学传感器，位于椭圆形容器内，而成骨细胞粘附在更平坦的骨表面。尚不清楚由附着的几何形状决定的形态差异对于细胞流变学和机械传感是否重要。我们开发了一种新的方法，用于研究不同形态下的骨细胞的流变学和机械敏感性，使用原子力显微镜和我们的光镊双粒子测定。我们发现，MLO-Y 4骨细胞在扁平和贴壁（> 1 kPa）时的弹性常数与圆形但部分贴壁（< 1 kPa）时的弹性常数有很大差异。圆形悬浮的MLO-Y 4骨细胞、MC 3 T3-E1成骨细胞和原代成骨细胞的弹性常数类似地< 1 kPa。通过监测一氧化氮（NO）的释放，骨中的一种重要的信号分子，圆形悬浮的MLO-Y 4骨细胞的机械敏感性进行了研究。初步观察到高NO释放从圆形悬浮的MLO-Y 4骨细胞在响应类似于5 pN的力在这里报道，与以前的研究相比，扁平的细胞通常释放较少的NO，而被更高的力刺激。我们的研究结果表明，一个圆形的细胞形态支持较不僵硬的细胞骨架配置相比，扁平的细胞形态。这意味着骨细胞利用其在体内的椭圆形形态来感知有益于骨健康的小应变。我们的试验提供了新的机会，在体外研究下，一个控制的悬浮形态与通常研究的粘附形态。(c)2008爱思唯尔有限公司保留所有权利。
There is increasing evidence that cell function and mechanical properties are closely related to morphology. However, most in vitro studies investigate flat adherent cells, which might not reflect physiological geometries in vivo. Osteocytes, the mechanosensors in bone, reside within ellipsoid containment, while osteoblasts adhere to flatter bone surfaces. It is unknown whether morphology difference, dictated by the geometry of attachment is important for cell theology and mechanosensing. We developed a novel methodology for investigating the theology and mechanosensitivity of bone cells under different morphologies using atomic force microscopy and our two-particle assay for optical tweezers. We found that the elastic constant of MLO-Y4 osteocytes when flat and adherent (> 1 kPa) largely differed when round but partially adherent (< 1 kPa). The elastic constant of round suspended MLO-Y4 osteocytes, MC3T3-E1 osteoblasts, and primary osteoblasts were similarly < 1 kPa. The mechanosensitivity of round suspended MLO-Y4 osteocytes was investigated by monitoring nitric oxide (NO) release, an essential signaling molecule in bone. A preliminary observation of high NO release from round suspended MLO-Y4 osteocytes in response to similar to 5 pN force is reported here, in contrast with previous studies where flat cells routinely release lesser NO while being stimulated with higher force. Our results suggest that a round cellular morphology supports a less stiff cytoskeleton configuration compared with flat cellular morphology. This implies that osteocytes take advantage of their ellipsoid morphology in vivo to sense small strains benefiting bone health. Our assay provides novel opportunities for in vitro studies under a controlled suspended morphology versus commonly studied adherent morphologies. (c) 2008 Elsevier Ltd. All rights reserved.