Solid-fluid transition and cell sorting in epithelia with junctional tension fluctuations.

Area of Science:

• Biophysics
• Developmental Biology
• Cell Biology

Background:

• Tissues exhibit solid-like and fluid-like behaviors crucial for development and disease.
• Transitions are typically linked to cell shape changes and motility.
• An alternative mechanism involving stochastic dynamics driven by molecular motors is explored.

Purpose of the Study:

• To investigate the role of junctional molecular motor turnover in driving tissue solid-fluid transitions.
• To analyze cell-sorting dynamics in two-component tissues based on differential adhesion and junctional fluctuations.
• To identify new mechanisms governing tissue fluidity and cell sorting.

Main Methods:

• Studied single-component tissues to correlate cell-shape index with effective diffusion coefficient.
• Generalized the model to two-component tissues to analyze sorting kinetics.
• Investigated sorting driven by differential adhesion and differential junctional fluctuations.

Main Results:

• The mean cell-shape index uniquely identifies the solid-fluid transition point.
• Differential junctional fluctuations drive cell sorting, with observed discrepancies from established scaling relations.
• Differential fluctuations efficiently sort two solid-like tissues separated by a fluid boundary.

Conclusions:

• Junctional molecular motor dynamics provide an alternative mechanism for tissue solid-fluid transitions.
• Cell-shape index and junctional fluctuations are key determinants of tissue mechanical states and sorting.
• This framework offers new perspectives on morphogenesis and disease-related tissue dynamics.