Motility driven glassy dynamics in confluent epithelial monolayers

Area of Science:

• Biophysics
• Cell Biology
• Condensed Matter Physics

Background:

• Cellular monolayers transition between solid-like jammed and fluid-like flowing states during biological processes.
• The epithelial-to-mesenchymal transition (EMT) involves cells becoming motile, impacting tissue dynamics.
• Understanding the interplay between cell motility and glassy dynamics is crucial for processes like embryonic development and cancer progression.

Purpose of the Study:

• To develop an analytical framework explaining how cell motility drives glassy dynamics in epithelial systems.
• To provide deeper insights into the mechanisms underlying the epithelial-to-mesenchymal transition (EMT).

Main Methods:

• Development of a novel analytical theory inspired by established glass theory.
• Utilizing simulations of the active Vertex model to test theoretical predictions.
• Investigating the role of effective persistence time-scale and rotational diffusivity.

Main Results:

• A crucial finding is that confluency affects the effective persistence time-scale of active force (Deffr).
• Deffr differs from bare rotational diffusivity (Dr) due to cell shape dynamics, which rectify force dynamics.
• The theory predicts that Deffr saturates at large Dr values and equals Dr at small Dr values.

Conclusions:

• The developed theory provides essential insights into active glassy dynamics in epithelial monolayers.
• The novel effect of Deffr is critical for interpreting existing and new simulation data.
• This work offers a framework for understanding how cell motility influences tissue-level behaviors during biological transitions.