Universal Persistent Brownian Motions in Confluent Tissues.

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Biological tissues are active materials with nonequilibrium dynamics.
• Cellular force generation mechanisms, including traction forces and junctional tension fluctuations, drive tissue dynamics.
• Understanding these forces is crucial for deciphering tissue behavior.

Purpose of the Study:

• To compare the effects of traction forces and junctional tension fluctuations on confluent tissue dynamics.
• To investigate the universal features and nonuniversal correlations in active tissue dynamics.
• To establish a minimal framework for describing tissue dynamics and inferring dominant active forces.

Main Methods:

• Utilized a two-dimensional active foam model.
• Compared distinct modes of cellular activity: traction forces and junctional tension fluctuations.
• Analyzed cell shapes, rearrangement statistics, spatiotemporal correlations, and cellular motion.

Main Results:

• Different active forces produced distinct cell shapes, rearrangement statistics, and fluid-state correlations.
• Long-time cellular motion universally converged to persistent Brownian dynamics.
• Correlations between cell geometry, rearrangement rate, and fluidity were nonuniversal and force-dependent.

Conclusions:

• Persistent Brownian motion offers a minimal yet universal framework for describing active tissue dynamics.
• Distinct active forces leave identifiable signatures in tissue structure and dynamics.
• The study enables inference of dominant active forces in fluid-state tissues based on observed signatures.