Determining mechanical features of modulated epithelial monolayers using subnuclear particle tracking

Area of Science:

• Cellular mechanics
• Biophysics
• Molecular biology

Background:

• Cellular forces are crucial for tissue homeostasis and collective behaviors, mediated by motor proteins.
• Understanding how cells perceive and transmit mechanical forces is vital for tissue engineering and disease research.

Purpose of the Study:

• To introduce and validate a novel technique, SINK (sensors from intranuclear kinetics), for detecting cellular force propagation.
• To investigate the mechanical response of epithelial cell monolayers to substrate stiffness and monolayer defects.

Main Methods:

• Utilized chromatin dynamics as an indicator of intracellular force propagation (SINK technique).
• Experimentally disrupted epithelial monolayers and altered substrate stiffness to observe cellular responses.
• Analyzed strain fields and force propagation patterns within heterogeneous cell monolayers.

Main Results:

• Chromatin dynamics exhibited a substrate stiffness-dependent response in epithelial monolayers.
• Cell monolayers demonstrated behavior consistent with a colloidal assembly, not a continuum.
• A characteristic length of approximately 50 µm was determined for mechanical defect recovery in cell monolayers.

Conclusions:

• The SINK technique provides a powerful tool for studying cellular force dynamics.
• Findings offer insights into diseases involving cellular heterogeneities, such as cancer and atherosclerosis.
• The colloidal nature of cell monolayers has implications for understanding tissue mechanics and development.