Emergence, Pattern, and Frequency of Spontaneous Waves in Spreading Epithelial Monolayers

Area of Science:

• Cell biology
• Biophysics
• Mathematical modeling

Background:

• Collective cell motion is crucial for tissue development and repair.
• Epithelial expansions often display spontaneous wave-like phenomena.
• The underlying mechanisms driving these emergent waves remain poorly understood.

Purpose of the Study:

• To elucidate the fundamental mechanisms governing emergent wave phenomena in epithelial expansions.
• To investigate the relationship between wave characteristics (frequency, pattern) and cellular properties.
• To develop a quantitative model for predicting collective cell motion dynamics.

Main Methods:

• Development of a discrete vertex model incorporating a mechanochemical feedback loop.
• Numerical simulations to analyze the spatiotemporal evolution of spreading epithelia.
• Analytical derivations to understand wave dynamics and scaling laws.

Main Results:

• Identified a power-law dependence of wave frequency on local cell density heterogeneities (scaling exponent of -1/2).
• Demonstrated the model's capability to capture distinct wave patterns (X-, W-, and V-modes).
• Unveiled that the distribution of active self-propulsion forces governs the phase transitions between wave modes.

Conclusions:

• The proposed mechanochemical model provides a quantitative framework for studying collective cell motion.
• Emergent wave phenomena in epithelia are governed by cell density heterogeneities and self-propulsion forces.
• This work opens avenues for rigorous investigations into cell group dynamics and pattern formation.