Mgharbel Abbas, Migdal Camille, Bouchonville Nicolas, Dupenloup Paul, Fuard David, Lopez-Soler Eline, Tomba Caterina, Courçon Marie, Gulino-Debrac Danielle, Delanoë-Ayari Héléne, Nicolas Alice
University Grenoble Alps, CNRS, LTM, 38000 Grenoble, France.
University Grenoble Alps, CEA, CNRS, Inserm, BIG-BCI, 38000 Grenoble, France.
Nanomaterials (Basel). 2022 Feb 15;12(4):648. doi: 10.3390/nano12040648.
Cell rigidity sensing-a basic cellular process allowing cells to adapt to mechanical cues-involves cell capabilities exerting force on the extracellular environment. In vivo, cells are exposed to multi-scaled heterogeneities in the mechanical properties of the surroundings. Here, we investigate whether cells are able to sense micron-scaled stiffness textures by measuring the forces they transmit to the extracellular matrix. To this end, we propose an efficient photochemistry of polyacrylamide hydrogels to design micron-scale stiffness patterns with kPa/µm gradients. Additionally, we propose an original protocol for the surface coating of adhesion proteins, which allows tuning the surface density from fully coupled to fully independent of the stiffness pattern. This evidences that cells pull on their surroundings by adjusting the level of stress to the micron-scaled stiffness. This conclusion was achieved through improvements in the traction force microscopy technique, e.g., adapting to substrates with a non-uniform stiffness and achieving a submicron resolution thanks to the implementation of a pyramidal optical flow algorithm. These developments provide tools for enhancing the current understanding of the contribution of stiffness alterations in many pathologies, including cancer.
细胞刚度感知——一种使细胞能够适应机械信号的基本细胞过程——涉及细胞对细胞外环境施加力的能力。在体内，细胞会暴露于周围环境机械特性的多尺度异质性中。在此，我们通过测量细胞传递到细胞外基质的力来研究细胞是否能够感知微米尺度的刚度纹理。为此，我们提出了一种高效的聚丙烯酰胺水凝胶光化学方法，以设计具有千帕/微米梯度的微米尺度刚度模式。此外，我们还提出了一种用于粘附蛋白表面涂层的原创方案，该方案能够将表面密度从完全耦合调整为完全独立于刚度模式。这证明细胞通过调整对应于微米尺度刚度的应力水平来拉动其周围环境。这一结论是通过牵引力显微镜技术的改进实现的，例如，适应具有不均匀刚度的底物，并由于实施了金字塔光流算法而实现了亚微米分辨率。这些进展为深入理解刚度改变在包括癌症在内的许多病理过程中的作用提供了工具。
