Fibronectin fibrillogenesis facilitates mechano-dependent cell spreading, force generation, and nuclear size in human embryonic fibroblasts.
Fibronectin fibrillogenesis facilitates mechano-dependent cell spreading, force generation, and nuclear size in human embryonic fibroblasts.
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DOI：
10.1039/c5ib00217f
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发表时间：
2015-11
期刊：
影响因子：
--
通讯作者：
Lemmon CA
中科院分区：
文献类型：
--
作者：
Scott LE;Mair DB;Narang JD;Feleke K;Lemmon CA
细胞对来自它们所附着的基质的机械信号作出反应。这些机械信号驱动细胞迁移、增殖、分化和存活。先前的研究已经强调了基底硬度直接改变细胞功能的三种特定机制：增加硬度驱动1）更大的收缩力; 2）增加细胞伸展和大小;和3）改变核变形。虽然研究表明，基质力学是一个重要的线索，细胞外基质（ECM）的作用在很大程度上被忽视。ECM是机械传感系统的关键组成部分，原因有两个：1）许多ECM原纤维通过施加细胞产生的力组装，以及2）ECM蛋白具有独特的机械性质，这无疑会改变细胞所感知的局部刚度。我们特别关注ECM蛋白纤连蛋白（FN）的作用，它在从头组织产生中起着关键作用。在这项研究中，我们首先测量基板刚度对人胚胎成纤维细胞的影响，通过将细胞接种到不同刚度的微制造柱阵列（MPA）上。细胞通过产生更大的力、扩散到更大的尺寸和改变核几何形状来响应增加的基底刚度。这些细胞还组装FN原纤维在所有刚度，最佳组装发生在约6千帕。然后，我们抑制FN组装，这导致收缩力产生，细胞扩散和核几何形状在所有刚度显着减少。这些发现表明，FN纤维在促进细胞对底物硬度的反应中起着关键作用。
Cells respond to mechanical cues from the substrate to which they are attached. These mechanical cues drive cell migration, proliferation, differentiation, and survival. Previous studies have highlighted three specific mechanisms through which substrate stiffness directly alters cell function: increasing stiffness drives 1) larger contractile forces; 2) increased cell spreading and size; and 3) altered nuclear deformation. While studies have shown that substrate mechanics are an important cue, the role of the extracellular matrix (ECM) has largely been ignored. The ECM is a crucial component of the mechanosensing system for two reasons: 1) many ECM fibrils are assembled by application of cell-generated forces, and 2) ECM proteins have unique mechanical properties that will undoubtedly alter the local stiffness sensed by a cell. We specifically focused on the role of the ECM protein fibronectin (FN), which plays a critical role in de novo tissue production. In this study, we first measured the effects of substrate stiffness on human embryonic fibroblasts by plating cells onto microfabricated pillar arrays (MPAs) of varying stiffness. Cells responded to increasing substrate stiffness by generating larger forces, spreading to larger sizes, and altering nuclear geometry. These cells also assembled FN fibrils across all stiffnesses, with optimal assembly occurring at approximately 6 kPa. We then inhibited FN assembly, which resulted in dramatic reductions in contractile force generation, cell spreading, and nuclear geometry across all stiffnesses. These findings suggest that FN fibrils play a critical role in facilitating cellular responses to substrate stiffness.