Defined extracellular matrix compositions support stiffness-insensitive cell spreading and adhesion signaling
James R W Conway1, Aleksi Isomursu1, Gautier Follain1
1Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku FI-20520, Finland.
Summary
Cells can spread on soft substrates, challenging the idea that stiffness is always required. Specific extracellular matrix (ECM) mixtures and adjusted cell machinery enable "stiff-like" spreading on soft materials.
Area of Science:
- Cell biology
- Biophysics
- Mechanobiology
Background:
- Integrin-mediated adhesion to the extracellular matrix (ECM) is crucial for cellular mechanosensing and signaling.
- The mechanical properties and composition of the ECM influence cell behavior.
- Current in vitro models often link increased stiffness to enhanced cell spreading and mechanosensitive signaling, despite most human tissues being soft.
Purpose of the Study:
- To investigate the interplay between ECM composition and matrix rigidity on cell spreading and signaling.
- To develop and utilize a high-resolution system for screening cell phenotypes on defined substrate stiffnesses and ECM mixtures.
- To understand the mechanisms underlying cell spreading on soft substrates.
Main Methods:
- Development of a matrix spot array system for high-resolution screening of cell phenotypes.
- Application of the system to both cancer and normal cells on defined substrate stiffnesses and ECM compositions.
- Utilizing the motor-clutch model for simulations of cell adhesion on soft substrates with varying ECM-integrin-cytoskeleton connections.
Main Results:
- Identification of specific ECM mixtures that promote stiffness-insensitive cell spreading on soft substrates.
- Demonstration that increased integrin-cytoskeleton (clutch) engagement on certain ECM mixtures supports cell spreading on soft matrices.
- Observation that partial inhibition of actomyosin contractility can augment cell spreading on soft substrates.
Conclusions:
- Cell spreading on soft substrates is achievable and influenced by a balance between cellular contractile and adhesive forces.
- Specific ECM compositions can enable "stiff-like" cell spreading on soft materials, independent of substrate stiffness.
- This finding offers a new perspective for in vitro mechanobiology, highlighting mechanisms for effective cell function and signaling on soft biological materials.
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