Force propagation between epithelial cells depends on active coupling and mechano-structural polarization

Area of Science:

• Cellular mechanics
• Biophysics
• Tissue engineering

Background:

• Cell-generated forces are crucial for tissue development, wound healing, and cancer.
• Mechanical signals transmit faster than biochemical signals in tissues.
• A quantitative model for force transmission and cellular response is lacking.

Purpose of the Study:

• To quantitatively describe force transmission from a sender cell to a receiver cell in a minimal epithelial model.
• To investigate the role of mechano-structural polarization in modulating force propagation.
• To understand how cellular organization impacts signal strength and tissue elasticity.

Main Methods:

• A minimal model system of two epithelial cells ('cell doublet') on an H-pattern micropattern.
• Optogenetic activation of RhoA in a sender cell to induce contractility.
• Traction force microscopy and monolayer stress microscopy to measure mechanical responses.

Main Results:

• Receiver cells exhibit an active response, forming a coherent unit with sender cells.
• Force propagation and receiver cell response are influenced by cell-matrix adhesion and mechano-structural polarization.
• Receiver cell response is enhanced when polarization is perpendicular to force propagation, similar to the Poisson effect.

Conclusions:

• Cellular organization and active mechanical responses are vital for maintaining signal strength in tissues.
• These mechanisms contribute to the emergence of elasticity, allowing signals to propagate over long distances.
• The findings are applicable to small tissue systems and have implications for understanding tissue-level mechanics.