Cell response to substrate rigidity is regulated by active and passive cytoskeletal stress
- 22 May 2020
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 117 (23), 12817-12825
- https://doi.org/10.1073/pnas.1917555117
Abstract
Morphogenesis, tumor formation, and wound healing are regulated by tissue rigidity. Focal adhesion behavior is locally regulated by stiffness; however, how cells globally adapt, detect, and respond to rigidity remains unknown. Here, we studied the interplay between the rheological properties of the cytoskeleton and matrix rigidity. We seeded fibroblasts onto flexible microfabricated pillar arrays with varying stiffness and simultaneously measured the cytoskeleton organization, traction forces, and cell-rigidity responses at both the adhesion and cell scale. Cells adopted a rigidity-dependent phenotype whereby the actin cytoskeleton polarized on stiff substrates but not on soft. We further showed a crucial role of active and passive cross-linkers in rigidity-sensing responses. By reducing myosin II activity or knocking down α-actinin, we found that both promoted cell polarization on soft substrates, whereas α-actinin overexpression prevented polarization on stiff substrates. Atomic force microscopy indentation experiments showed that this polarization response correlated with cell stiffness, whereby cell stiffness decreased when active or passive cross-linking was reduced and softer cells polarized on softer matrices. Theoretical modeling of the actin network as an active gel suggests that adaptation to matrix rigidity is controlled by internal mechanical properties of the cytoskeleton and puts forward a universal scaling between nematic order of the actin cytoskeleton and the substrate-to-cell elastic modulus ratio. Altogether, our study demonstrates the implication of cell-scale mechanosensing through the internal stress within the actomyosin cytoskeleton and its coupling with local rigidity sensing at focal adhesions in the regulation of cell shape changes and polarity.Keywords
Funding Information
- Ligue Contre le Cancer (NA)
- Agence Nationale de la Recherche (ANR-17-CE13-0013)
- EC | FP7 | FP7 Ideas: European Research Council (CoG-617233)
- Agence Nationale de la Recherche (ANR-17-CE-13-0022)
- Mechanobiology Institute, Singapore (NA)
- Mechanobiology Institute, Singapore (NA)
- Agence Nationale de la Recherche (ANR-11-LABX-0071)
- Singapore Ministry of Education Academic Research (MOE2016-T3-1-002)
- Agence Nationale de la Recherche (ANR-18-IDEX-0001)
This publication has 57 references indexed in Scilit:
- Evidence of a large-scale mechanosensing mechanism for cellular adaptation to substrate stiffnessProceedings of the National Academy of Sciences of the United States of America, 2012
- Tension is required but not sufficient for focal adhesion maturation without a stress fiber templateThe Journal of cell biology, 2012
- An AFM-Based Stiffness Clamp for Dynamic Control of RigidityPLOS ONE, 2011
- α-Actinin-4 Is Essential for Maintaining the Spreading, Motility and Contractility of FibroblastsPLOS ONE, 2010
- Probing Cellular Traction Forces by Micropillar Arrays: Contribution of Substrate Warping to Pillar DeflectionNano Letters, 2010
- Neuronal IP33-Kinase is an F-actin–bundling Protein: Role in Dendritic Targeting and Regulation of Spine MorphologyMolecular Biology of the Cell, 2009
- Single-cell response to stiffness exhibits muscle-like behaviorProceedings of the National Academy of Sciences of the United States of America, 2009
- Talin depletion reveals independence of initial cell spreading from integrin activation and tractionNature, 2008
- GEF-H1 Couples Nocodazole-induced Microtubule Disassembly to Cell Contractility via RhoAMolecular Biology of the Cell, 2008
- Anisotropy of cell adhesive microenvironment governs cell internal organization and orientation of polarityProceedings of the National Academy of Sciences of the United States of America, 2006