Reversible superdeformability of hiPSC epithelial cortinoids

Area of Science:

• Cell biology
• Biophysics
• Developmental biology

Background:

• Epithelial tissues must deform significantly during development.
• Induced pluripotent stem cell (iPSC)-derived epithelial shells are model systems for studying tissue mechanics.
• Understanding the mechanisms of epithelial deformability is crucial for developmental biology.

Purpose of the Study:

• To investigate the mechanical properties and deformability mechanisms of iPSC-derived epithelial shells.
• To identify the role of the cytoskeleton in accommodating large deformations.
• To model the relationship between cytoskeletal behavior and shell mechanics.

Main Methods:

• Utilizing inflation-deflation assays to apply mechanical stress to iPSC shells.
• Employing high-resolution imaging to visualize cytoskeletal dynamics.
• Developing a theoretical and computational model to simulate shell behavior.

Main Results:

• iPSC shells are weakly pressurized and exhibit extreme deformability.
• Reversible soft modes of deformation, driven by cytoskeletal instabilities (actin tilt and bend), buffer mechanical loads.
• These instabilities decouple stretching from lateral extension, acting as elastic safety valves.
• The model successfully explains pressure-strain softening and the role of tilt and bend instabilities.

Conclusions:

• iPSC shells utilize reversible cytoskeletal instabilities as mechanical buffers.
• This mechanism allows for robust tolerance of large deformations in developing epithelia.
• The findings provide insights into the biophysical principles governing tissue morphogenesis.