“Geometry of Cell Jamming: New biology, Surprising Physics, and Useful Ideas About Airway Epithelium”
As an injury heals, an embryo develops, or a carcinoma spreads, epithelial cells systematically change their shape. In each of these processes cell shape is studied extensively whereas variability of shape from cell-to-cell is regarded most often as biological noise. But where do cell shape and its variability come from? Here we report that cell shape and shape variability are mutually constrained through a relationship that is purely geometrical. That relationship is shown to govern processes as diverse as maturation of the pseudostratified bronchial epithelial layer cultured from non-asthmatic or asthmatic donors, and formation of the ventral furrow in the Drosophila embryo. Across these and other epithelial systems, shape variability collapses to a family of distributions that is common to all. These findings suggest a connection between jamming and geometry that spans living organisms and inert jammed systems, and thus transcends system details. Although molecular events are needed for any complete theory of cell shape and cell packing, observations point to the hypothesis that jamming behavior at larger scales of organization sets overriding geometrical constraints.
Dr. Jeffrey J. Fredberg has worked to bridge the physical sciences with the life sciences at the levels of organ, tissue, and cell. His group has addresses basic material properties expressed by every eukaryotic cell, such as deformability, contractility, malleability, and motility. More recently his group has also turned attention to collective cellular migration as occurs with bronchial epithelial cells in asthma, with cell invasion in breast cancer, and with embryonic development in Drosophila melanogaster.