Title: On the origin of universal cell shape variability in confluent epithelial monolayers

Speaker: Dr. Saroj Kumar Nandi, TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad

Abstract: Why do cells change their shapes during development and disease? Cell shape can influence crucial biological functions and control organ shape. However, the cell-to-cell shape varies in a tissue. Recent works show that shape variability in different epithelial monolayers follows a nearly universal distribution. What is the origin of this universality, and how is it related to the physical variables? In my talk, I will discuss a mean-field analytical theory for cell shape characterized via aspect ratio (AR). We find that a single parameter, α, containing all the system-specific details, describes the probability distribution function (PDF) of AR: this leads to a universal relation between the standard deviation and the average of AR. The PDF for the scaled AR is not strictly but nearly universal. The functional form is a direct consequence of a mathematical property. The theory is verified in simulations of two distinct models of epithelial monolayers and agrees well with existing experiments. Our results imply that cell shape variability is inevitable, where a single parameter describes both statics and dynamics and provides a framework to analyze and compare diverse epithelial systems. I will also discuss some implications of our results.