Reciprocal cell-ECM dynamics generate supracellular fluidity underlying spontaneous follicle patterning

Area of Science:

• Developmental Biology
• Cell Mechanics
• Tissue Engineering

Background:

• Vertebrate embryogenesis involves complex tissue formation through coordinated cell behavior.
• Avian skin follicle assembly relies on dermal mechanical forces, but the initiation mechanism is unclear.

Purpose of the Study:

• To investigate how cell mechanics initiate follicle patterning in avian skin.
• To understand the interplay between dermal cells and the extracellular matrix (ECM) in pattern formation.

Main Methods:

• Reconstitution of follicle patterning initiation ex vivo using dissociated avian dermal cells and collagen.
• Experimental observation of cell-ECM interactions and mechanical rearrangements.
• Theoretical modeling of cell-ECM dynamics as an active contractile fluid.

Main Results:

• Contractile dermal cells actively rearrange the ECM, leading to increased cell alignment.
• A mechanically unlinked cell collective transforms into an ordered continuum with long-range order.
• The ordered cell-ECM layer exhibits behavior of an active contractile fluid, spontaneously forming regular patterns.

Conclusions:

• Mesenchymal dynamics and cell-ECM interactions are crucial for generating cell-level ordering.
• A fluid instability mechanism drives tissue-level patterning during follicle formation.
• This process may be relevant to other morphological symmetry-breaking events in development.