Filamentous network mechanics and active contractility determine cell and tissue shape.
Ilka B Bischofs1, Franziska Klein, Dirk Lehnert
1University of Heidelberg, Bioquant 0013, D-69120 Heidelberg, Germany.
Biophysical Journal
|July 5, 2008
Summary
Cell and tissue shape, crucial for function, is governed by a modified Laplace law. This law, derived from filamentous network mechanics and contractility, explains how tension distribution dictates geometry across scales.
Area of Science:
- Biophysics
- Cell Biology
- Tissue Engineering
Background:
- Cell and tissue shape are intrinsically linked to their biological function, often mediated by tension distribution.
- Understanding the geometric principles governing cell and tissue morphology is essential for predicting and controlling biological processes.
Purpose of the Study:
- To identify universal shape determinants across cellular and tissue scales.
- To elucidate the physical mechanisms underlying the observed shape regulations.
- To develop a quantitative model explaining shape-function relationships.
Main Methods:
- Utilized micropatterned substrates with small adhesive islands for cell culture.
- Employed fibroblast-populated collagen gels pinned to a flat substrate.
- Performed quantitative image analysis and developed theoretical models incorporating filamentous network mechanics and contractility.
- Conducted actomyosin inhibition experiments to probe regulatory mechanisms.
Main Results:
- Observed that cell and tissue shapes conform to inward-curved circular arcs.
- Found that arc radii scale with the spanning distance between pinning points.
- Developed a modified Laplace law that accurately predicts experimental observations, surpassing the limitations of the standard Laplace law.
- Identified two distinct control modes for cell shape: motor contractility and actin cytoskeleton structural dynamics.
Conclusions:
- Filamentous network mechanics and contractility generate a modified Laplace law governing cell and tissue shape.
- This unified model explains shape determinants at both cellular and tissue levels.
- Cell shape regulation involves a interplay between actomyosin contractility and actin cytoskeleton remodeling.
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