Extracellular matrix rigidity governs smooth muscle cell motility in a biphasic fashion
Extracellular matrix rigidity governs smooth muscle cell motility in a biphasic fashion
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DOI：
10.1002/jcp.20274
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发表时间：
2005-07-01
影响因子：
5.6
通讯作者：
Putnam, AJ
中科院分区：
文献类型：
--
作者：
Peyton, SR;Putnam, AJ
越来越多的证据表明，细胞外基质（ECM）固有的机械信号在调节细胞行为方面可能与其化学特性同样重要。我们假设 ECM 的机械性能直接调节血管平滑肌细胞 (SMC) 的运动性，并使用具有可调节机械性能的聚丙烯酰胺基材测试了这一假设。对跨越一系列硬度（丙烯酰胺/双丙烯酰胺比例在 5/0.1% 和 15/1.2% 之间的杨氏模量值分别为 1.0 至 308 kPa）的均匀顺应水凝胶的迁移速度的量化揭示了对基底顺应性的双相依赖性，表明存在能够支持最大迁移的最佳基底刚度。这种最佳刚度的值根据共价附着在基材上的 ECM 蛋白的浓度而变化。具体而言，在纤连蛋白理论密度为0.8μg/cm(2)的基质上，在51.9kPa凝胶上实现了0.74+/-0.09μm/min的最大速度；在理论密度为 8.0 μ g/cm(2) 纤连蛋白的基质上，在较软的 21.6 kPa 凝胶上出现 0.72 +/- 0.06 μ m/min 的最大速度。用 Rho/Rho 激酶 (ROCK) 途径抑制剂 Y27632 预处理细胞，将观察到的最大值降低到与非最佳刚度的值相当的值。与此同时，通过蛋白质印迹法定量 TritonX 不溶性纽蛋白，结合定性荧光显微镜，揭示粘着斑和肌动蛋白应力纤维的形成也取决于 ECM 硬度。综合起来，这些数据表明，基础 ECM 的机械特性通过破坏假定的细胞-ECM 力平衡来调节 SMC 中 Rho 介导的收缩性，从而调节细胞骨架组装并最终调节细胞迁移。
Increasing evidence suggests that mechanical cues inherent to the extracellular matrix (ECM) may be equally as critical as its chemical identity in regulating cell behavior. We hypothesized that the mechanical properties of the ECM directly regulate the motility of vascular smooth Muscle cells (SMCs) and tested this hypothesis using polyacrylamide substrates with tunable mechanical properties. Quantification of the migration speed on uniformly compliant hydrogels spanning a range of stiffnesses (Young's moduli values from 1.0 to 308 kPa for acrylamide/bisacrylamide ratios between 5/0.1% and 15/1.2%, respectively) revealed a biphasic dependence on substrate compliance, suggesting the existence of an optimal substrate stiffness capable of supporting maximal migration. The value of this optimal stiffness shifted depending on the concentration of ECM protein covalently attached to the substrate. Specifically, on substrates presenting a theoretical density of 0.8 mu g/cm(2) fibronectin, the maximum speed of 0.74 +/- 0.09 mu m/min was achieved on a 51.9 kPa gel; on substrates presenting a theoretical density of 8.0 mu g/cm(2) fibronectin, the maximum speed of 0.72 +/- 0.06 mu m/min occurred on a softer 21.6 kPa gel. Pre-treatment of cells with Y27632, an inhibitor of the Rho/Rho-kinase (ROCK) pathway, reduced these observed maxima to values comparable to those on non-optimal stiffnesses. In parallel, quantification of TritonX-insoluble vinculin via Western blotting, coupled with qualitative fluorescent microscopy, revealed that the formation of focal adhesions and actin stress fibers also depends on ECM stiffness. Combined, these data suggest that the mechanical properties of the underlying ECM regulate Rho-mediated contractility in SMCs by disrupting a presumptive cell-ECM force balance, which in turn regulates cytoskeletal assembly and ultimately, cell migration.