Minimizing cell number fluctuations in self-renewing tissues with a stem-cell niche

Area of Science:

• Cell biology
• Developmental biology
• Mathematical modeling

Background:

• Self-renewing tissues must maintain a stable number of proliferating cells.
• Cell number maintenance can occur at single-cell or population levels.
• Population-level maintenance can involve fluctuations in proliferating cell numbers, often assumed to be reduced by asymmetric divisions.

Purpose of the Study:

• To investigate a model of cell proliferation within a fixed-size stem cell niche.
• To determine conditions that minimize fluctuations in proliferating cell numbers.
• To identify experimental signatures of optimal cell proliferation strategies.

Main Methods:

• Modeling cell proliferation dynamics within a stem cell niche.
• Explicitly modeling cells both inside and outside the niche.
• Analyzing clone size distributions to detect model signatures.

Main Results:

• Fluctuations in proliferating cell numbers are minimized when the growth rate difference between the niche and the rest of the tissue is maximized.
• Symmetric cell divisions (producing either two proliferative or two non-proliferative daughter cells) are optimal for minimizing fluctuations.
• This optimal proliferation strategy leaves detectable signatures in clone size distributions.

Conclusions:

• Contrary to common assumptions, symmetric divisions and maximized growth rate differences optimize cell number stability in self-renewing tissues.
• The identified signatures in clone size distributions offer a potential method for experimental validation.
• This research provides insights into the mechanisms governing tissue homeostasis and stem cell dynamics.