Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
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DOI：
10.1016/j.jbiomech.2005.08.026
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发表时间：
2006-01-01
影响因子：
2.4
通讯作者：
Sato, Masaaki
中科院分区：
文献类型：
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作者：
Deguchi, Shinji;Ohashi, Toshiro;Sato, Masaaki
应力纤维（SFs），肌动蛋白纤维的收缩束，在贴壁细胞的力学转导中起着至关重要的作用，然而，SFs的机械性能知之甚少。在这里，我们测量了拉伸性能的单SF在体外操纵与杠杆。SFs从培养的血管平滑肌细胞中分离，低离子强度提取和去污剂提取的组合，并拉伸直至断裂。断裂力和杨氏模量（假设SF是各向同性的）平均为377 nN和1.45 MPa，分别比先前报道的肌动蛋白丝大约600倍和低3个数量级。在力-应变曲线中观察到应变诱导硬化。我们还发现，提取的SFs缩短到约80%的原始长度后，他们从基板上脱落的ATP-独立的方式，表明SFs有预先存在的应变在细胞质中。将单个SF从零应力长度拉伸回原始长度所需的力约为10 nN，这与贴壁细胞在单个贴壁位点施加的维持细胞完整性的牵引力水平相当。这些结果表明，SFs可以承受细胞内的应力，可能会影响整体细胞的机械性能，并将影响细胞内的应力分布和力传递机制在贴壁细胞的解释。(c)2005爱思唯尔有限公司保留所有权利。
Stress fibers (SFs), a contractile bundle of actin filaments, play a critical role in mechanotransduction in adherent cells; yet, the mechanical properties of SFs are poorly understood. Here, we measured tensile properties of single SFs by in vitro manipulation with cantilevers. SFs were isolated from cultured vascular smooth muscle cells with a combination of low ionic-strength extraction and detergent extraction and were stretched until breaking. The breaking force and the Young's modulus (assuming that SFs were isotropic) were, on average, 377 nN and 1.45 MPa, which were approximately 600-fold greater and three orders of magnitude lower, respectively, than those of actin filaments reported previously. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length in an ATP-independent manner after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN, which was comparable with the traction force level applied by adherent cells at single adhesion sites to maintain cell integrity. These results suggest that SFs can bear intracellular stresses that may affect overall cell mechanical properties and will impact interpretation of intracellular stress distribution and force-transmission mechanism in adherent cells. (c) 2005 Elsevier Ltd. All rights reserved.