Lecture 2: Physical Driving Forces of Epithelial Organisation
In the second lecture, I will focus on epithelial organisation. Epithelial cells adhere tightly, forming a polygonal lattice. The resulting cell packing exhibits striking universal regularities, regardless of the organism and organ. Several theories have been formulated to explain epithelial organisation, but none explains Lewis’ almost 100-year-old observation of a linear relationship between the average number of cell neighbours and the average apical cell area. I will discuss the physical driving forces that lead to the emergence of Lewis’ law, and that more generally explain apical epithelial organisation. Our work provides a link between epithelial organisation, cell division, and growth, and establishes computational frameworks such as LBIBCell as appropriate tools to simulate epithelial dynamics. In a second part, I will discuss growth control in epithelia. How tissue terminate growth is still an unsolved problem, and I will discuss candidate mechanisms.