Cell-size distribution in epithelial tissue formation and homeostasis

Area of Science:

• Cell biology
• Biophysics
• Developmental biology

Background:

• Coordinated cell proliferation is crucial for biological functions during development, regeneration, and homeostasis.
• Maintaining uniform cell size is a physiological requirement in many tissues.
• Understanding the mechanisms governing cell size distribution is a central problem in biology.

Purpose of the Study:

• To investigate the temporal evolution of cell size distribution in living tissues.
• To apply kinetic fragmentation theory to model tissue development and homeostasis.
• To explain how cell division times and spatial redistribution contribute to cell size homogeneity.

Main Methods:

• Application of kinetic fragmentation theory to model cell size dynamics.
• Theoretical predictions and numerical simulations of confluent non-homeostatic tissue cultures.
• Experimental validation using biological tissue data.

Main Results:

• The theory predicts a self-similar probability density function (PDF) for cell size.
• Experimental data and simulations confirm cell size distribution is self-similar.
• Cell division times were found to scale with cell size via a power-law relationship.
• Homeostatic conditions exhibit a stationary cell size distribution with lognormal tails.
• The shape of the cell size PDF is influenced by the redistribution of space from apoptotic cells.

Conclusions:

• Kinetic fragmentation theory accurately describes cell size distribution dynamics in tissues.
• Cell division timing and space redistribution are key mechanisms for maintaining cell size homogeneity.
• Apoptotic cell rates may also be size-dependent, further influencing tissue structure.