Cyclic stretch-induced stress fiber dynamics - Dependence on strain rate, Rho-kinase and MLCK
Cyclic stretch-induced stress fiber dynamics - Dependence on strain rate, Rho-kinase and MLCK
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DOI：
10.1016/j.bbrc.2010.09.046
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发表时间：
2010-10-22
影响因子：
3.1
通讯作者：
Kaunas, Roland
中科院分区：
文献类型：
--
作者：
Lee, Chin-Fu;Haase, Candice;Kaunas, Roland
应力纤维重组是非肌肉细胞对周期性拉伸的一种重要适应性反应，但这种重组发生的机制尚不清楚。通过使用活细胞显微镜分析应力纤维动力学，我们发现，应力纤维的重新取向垂直于在1 Hz的循环单轴拉伸的方向不涉及拆卸的应力纤维远端位于粘着斑网站。相反，这些远端通常用于组装新的应力纤维，其取向逐渐远离拉伸方向。然而，当拉伸频率降低到0.01 Hz时，不会引起应力纤维的分解和重新取向。用Rho激酶抑制剂Y27632处理将应力纤维减少为位于细胞周边的细纤维，其捆绑在一起以形成平行于以1 Hz拉伸的方向取向的粗纤维。相反，这些细纤维在受到0.01 Hz拉伸的细胞中保持弥散。在1 Hz的周期性拉伸也诱导肌动蛋白纤维的形成平行于拉伸的方向，在用肌球蛋白轻链激酶（MLCK）抑制剂ML-7处理的细胞，但这些纤维位于中心，而不是周边。这些结果揭示了应力纤维在肌动蛋白细胞骨架不同区域的周期性拉伸反应中重新定向的机制。(C)2010年爱思唯尔公司All rights reserved.
Stress fiber realignment is an important adaptive response to cyclic stretch for nonmuscle cells, but the mechanism by which such reorganization occurs is not known. By analyzing stress fiber dynamics using live cell microscopy, we revealed that stress fiber reorientation perpendicular to the direction of cyclic uniaxial stretching at 1 Hz did not involve disassembly of the stress fiber distal ends located at focal adhesion sites. Instead, these distal ends were often used to assemble new stress fibers oriented progressively further away from the direction of stretch. Stress fiber disassembly and reorientation were not induced when the frequency of stretch was decreased to 0.01 Hz, however. Treatment with the Rho-kinase inhibitor Y27632 reduced stress fibers to thin fibers located in the cell periphery which bundled together to form thick fibers oriented parallel to the direction of stretching at 1 Hz. In contrast, these thin fibers remained diffuse in cells subjected to stretch at 0.01 Hz. Cyclic stretch at 1 Hz also induced actin fiber formation parallel to the direction of stretch in cells treated with the myosin light chain kinase (MLCK) inhibitor ML-7, but these fibers were located centrally rather than peripherally. These results shed new light on the mechanism by which stress fibers reorient in response to cyclic stretch in different regions of the actin cytoskeleton. (C) 2010 Elsevier Inc. All rights reserved.