Mechanical stress inference for two dimensional cell arrays.

Area of Science:

• Developmental Biology
• Cell Biology
• Biophysics

Background:

• Morphogenesis relies on epithelial tissue mechanical rearrangements driven by cytoskeletal forces and cell adhesion.
• Cellular mechanical states and adhesion act as signals coordinating developmental processes.
• Direct in vivo measurement of sub-cellular mechanical stress is challenging, limiting understanding of mechanics in development.

Purpose of the Study:

• To present a computational approach for inferring mechanical forces within and between cells during epithelial tissue development.
• To model intracellular stress using bulk pressure and interfacial tension.
• To apply the developed method to analyze mechanical properties in specific developmental processes.

Main Methods:

• Utilized live imaging of morphogenetic processes and computational analysis of high-resolution epithelial tissue images.
• Modeled intracellular stress as cell- and interface-specific bulk pressure and interfacial tension.
• Applied the Mechanical Inverse method to epithelial cell layers during Drosophila ventral furrow formation and avian cochlea hair-cell determination, assuming mechanical equilibrium.

Main Results:

• Inferred relative magnitudes of forces acting within and between cells.
• Revealed mechanical anisotropy during Drosophila ventral furrow formation.
• Identified mechanical heterogeneity correlated with cell differentiation in avian hair-cell determination.

Conclusions:

• The Mechanical Inverse method provides a novel way to quantitatively assess cell and tissue mechanics in vivo.
• The findings highlight the importance of mechanical forces and heterogeneity in developmental processes.
• This approach enables detailed experimental testing of models of cell and tissue mechanics.