Fibronectin in aging extracellular matrix fibrils is progressively unfolded by cells and elicits an enhanced rigidity response
Fibronectin in aging extracellular matrix fibrils is progressively unfolded by cells and elicits an enhanced rigidity response
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DOI：
10.1039/b718714a
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发表时间：
2008-01-01
影响因子：
3.4
通讯作者：
Vogel, Viola
中科院分区：
文献类型：
--
作者：
Antia, Meher;Baneyx, Gretchen;Vogel, Viola
虽然基质或工程支架的机械性能可以控制细胞行为的许多方面，但细胞很快就会开始组装自己的基质，并最终对自己制造的细胞外基质(ECM)微环境做出反应。利用荧光共振能量转移(FRET)，我们检测到细胞在三天的过程中形成厚厚的三维(3D)基质时，细胞外基质成分纤维连接蛋白(FN)的构象发生了重大变化。这些数据提供了第一个证据，证明基质成熟发生，老化与纤维连接蛋白纤维的伸展增加有关，这导致单个蛋白质模块的二级结构至少部分展开。将FN在这些3D基质中的构象与细胞在刚性和柔性聚丙烯酰胺表面上构建的构象进行比较，结果表明，成熟基质中的细胞经历了一个逐渐增加刚性的微环境。此外，进一步的基质硬化是由活性FN纤维平行于延长的成纤维细胞的收缩轴排列引起的，这种细胞驱动的效应以前曾对其他纤维基质进行过描述。因此，成纤维细胞不仅导致基质展开，而且通过上调自身的刚性反应，对改变的FN基质属性做出相互反应。因此，我们的数据首次表明，与新组装的基质相比，成熟和老化的基质具有明显不同的物理和生化特性。这可能会让细胞专门识别基质的年龄。
While the mechanical properties of a substrate or engineered scaffold can govern numerous aspects of cell behavior, cells quickly start to assemble their own matrix and will ultimately respond to their self-made extracellular matrix (ECM) microenvironments. Using fluorescence resonance energy transfer (FRET), we detected major changes in the conformation of a constituent ECM protein, fibronectin (Fn), as cells fabricated a thick three-dimensional (3D) matrix over the course of three days. These data provide the first evidence that matrix maturation occurs and that aging is associated with increased stretching of fibronectin fibrils, which leads to at least partial unfolding of the secondary structure of individual protein modules. A comparison of the conformations of Fn in these 3D matrices with those constructed by cells on rigid and flexible polyacrylamide surfaces suggests that cells in maturing matrices experience a microenviroment of gradually increasing rigidity. In addition, further matrix stiffening is caused by active Fn fiber alignment parallel to the contractile axis of the elongated fibroblasts, a cell-driven effect previously described for other fibrillar matrices. The fibroblasts, therefore, not only cause matrix unfolding, but reciprocally respond to the altered Fn matrix properties by up-regulating their own rigidity response. Consequently, our data demonstrate for the first time that a matured and aged matrix has distinctly different physical and biochemical properties compared to a newly assembled matrix. This might allow cells to specifically recognise the age of a matrix.