Prof. Mukhtar Ullah

Stochastic Dynamics of Stem Cell Populations

"I am interested in cell populations in the stem cell niche."

With their ability to renew and divide into different specialized cell types, stem cells play a key role in the maintenance and repair of adult organisms.

The question we focus on is: How does the proportion of populations of differentiated cells relative to stem cells relates to the functioning of tissue?
Due to intrinsic cell-cell variation and environmental effects, cellular population dynamics have an unavoidable uncertainty (noise). To relate tissue fate to the noisy cell population dynamics, a modelling framework is needed in which biological questions of interest can be cast in terms of probabilities.
Most works in the literature on stem cells either ignore noise completely (by using deterministic approaches) or rely on detailed stochastic simulations of each cell. Our aim is to incorporate noise and yet keep modelling tractable to allow room for intuition.
Methods from large deviation theory will be employed in the Langevin framework so that questions about specific tissue fates can be cast in terms of probabilities of specific trajectories. Traditional approximations based on mean and variance cannot be used because of inherent bistabilities of stem cell populations.