Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young’s moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.

微环境生物物理因素在控制细胞形态、增殖、粘附和分化等细胞行为，甚至决定细胞命运方面起着基础性作用。细胞能够主动感知周围的机械微环境并改变其细胞形态以适应它。尽管细胞形态变化被认为是细胞与其机械微环境相互作用的第一步也是最重要的一步，但它们的调控网络并不完全清楚。在当前的研究中，我们生成了具有刚性（15:1，PDMS 弹性体与固化剂）和柔软 (45:1) 刚度的硅基弹性体聚二甲基硅氧烷 (PDMS) 基板，其杨氏模量为 ~450 kPa 和 46 kPa，分别为 并通过表征从分泌的细胞外蛋白层粘连蛋白 β1、粘着斑复合蛋白 FAK 到微丝束的轴偏移，阐明了软骨细胞细胞骨架重组的新途径，以响应底物刚度的变化。我们首先通过表征细胞扩散区域和细胞突触来显示软骨细胞中细胞骨架的变化。然后，我们发现了软骨细胞中分泌的细胞外连接蛋白、层粘连蛋白 β1 和粘着斑复合蛋白 FAK 对不同基质刚度的反应的变化。这两种蛋白质被证明通过 Co-IP 和共定位直接相互作用。接下来，我们通过显示微丝束的变化来显示 FAK 对细胞骨架组织的影响，并发现了潜在的中间调节剂。综合起来，