Active wetting of epithelial tissues

Area of Science:

• Biophysics
• Cell Biology
• Morphogenesis

Background:

• Tissue morphology changes are crucial in development, regeneration, and cancer.
• Previous analogies to fluid wetting lack a mechanistic understanding of active cellular forces.

Purpose of the Study:

• To investigate the transition between 2D epithelial monolayers and 3D spheroidal aggregates as an active wetting transition.
• To theoretically account for and measure active cellular forces driving tissue wetting.

Main Methods:

• Developed an active polar fluid model.
• Measured physical forces related to tissue size, contractility, adhesion, and substrate stiffness.
• Combined theoretical modeling with experimental force measurements.

Main Results:

• The 2D to 3D tissue transition is an active wetting transition, distinct from passive wetting.
• A critical tissue size for wetting transitions emerges from competing traction and contractile stresses.
• Active shape fluctuations are amplified during tissue dewetting.

Conclusions:

• Tissue spreading is a key example of active wetting.
• This active wetting framework explains morphological transitions in tissue morphogenesis and tumor progression.
• Introduced a novel physical scenario for understanding dynamic tissue morphology.