Continuum description of confluent tissues with spatial heterogeneous activity

Area of Science:

• Biophysics
• Computational Biology
• Materials Science

Background:

• Confluent tissues exhibit complex deformations driven by cellular activities.
• Understanding these deformations is crucial for developmental biology and tissue engineering.
• Existing models often lack a detailed description of heterogeneous cellular activities.

Purpose of the Study:

• To develop a continuum description for stationary and transient deformations in confluent tissues.
• To model heterogeneous cellular activities, specifically apical contractions.
• To validate the continuum model against vertex model simulations.

Main Methods:

• Defined a coarse-grained texture matrix field to represent cell shape and size.
• Derived a coarse-grained stress tensor for the vertex model.
• Modeled cellular activity as reductions in vertex model reference areas or perimeters.
• Compared continuum predictions with vertex model simulations.

Main Results:

• The continuum description accurately predicts spatiotemporal deformations in simulations.
• Medial activity results in isotropic pressure, while perimeter activity adds a deviatoric stress component.
• Fluctuations are more pronounced with medial activity due to reduced negative active shape feedback.

Conclusions:

• The developed continuum model effectively characterizes confluent tissue deformations under heterogeneous activities.
• The model distinguishes the mechanical consequences of medial versus perimeter cellular activity.
• Findings highlight the role of active shape feedback in regulating cellular variations within tissues.