Modelling cell turnover in a complex tissue during development.

Area of Science:

• Developmental Biology
• Cell Biology
• Quantitative Biology

Background:

• Organ growth relies on cell proliferation within specific compartments, involving complex transitions and regulated by cell cycle dynamics.
• Current methods for studying organ development in vivo are often descriptive, lacking quantitative precision for cell turnover parameters.
• Understanding cell cycle dynamics is crucial for assessing how genetic or environmental factors perturb organ development.

Purpose of the Study:

• To develop a novel quantitative framework for determining cell turnover in developing organs in vivo.
• To establish a mathematical model for calculating cell cycle length and assessing heterogeneity within cellular compartments.
• To enable quantification of cell exit from compartments without direct markers.

Main Methods:

• Combined cumulative cell-labeling with quantification of distinct cell-cycle phases.
• Developed a mathematical model, including a two-population model, to calculate cell cycle length and estimate proliferation rates.
• Applied the framework to the cap mesenchyme progenitor cell compartment in the developing mouse kidney.

Main Results:

• The framework successfully calculated cell cycle length and quantified cell exit from the cap mesenchyme compartment.
• The model accounts for potential heterogeneity in cell cycle length within a compartment.
• This approach provides a quantitative assessment of cell turnover dynamics in vivo.

Conclusions:

• The presented framework offers a robust, quantitative method for studying cell turnover in developing organs.
• This approach is applicable to various developmental systems, facilitating deeper insights into organogenesis.
• It moves beyond simple mitotic rate comparisons to provide a comprehensive understanding of compartment behavior.