Built Like a Beetle

The newly-discovered scutoid cell shape is proposed to optimize cell-packing in a way that saves energy.

Luis Escudero

As animals develop, their embryonic cells change shape over time. Epithelial cells—those on the inner and outer surfaces of organs and blood vessels—are the gymnasts of the cellular world, contorting their shapes as they bend to form organ tissue. Until now, cells involved in this curving process were thought to pack tightly together in one of only two ways, as either bottle- or column-shaped forms. A new study has added a third form, named “scutoid” by researchers because of its resemblance to the scutum and scutellum of insects such as beetles.

In a collaboration among sixteen scientists based in Spain, the United States, and the United Kingdom, computational modeling using Voronoi diagramming—after the Russian mathematician who conceptualized the technique—was used to calculate possible geometries of cells packed together to form tubes. The model predicted a new, complex scutoid shape with concave elements on its surface. The group then looked for the presence of these scutoid cells in real tissue. They first found them in the tubular salivary glands of fruit fly larvae. They also looked for scutoids in curved, but not tube-shaped, epithelial cells of fruit fly embryos. Here scutoids were present, but not as frequent as in the tubular salivary glands. Additionally, the researchers found scutoids in maturing egg chambers of fruit flies, with the percentage of scutoid cells decreasing as the rugby-ball-shaped chambers grew and elongated.

The researchers mathematically modeled why the scutoid shape might be formed. Since the amount of shared membrane between cells is important for energy-intensive adhesion, and cells try to minimize energy consumption, they proposed that scutoid geometry is an optimized, energy-saving cell packing solution.

Understanding cell shape is important to understanding cell-to-cell communication, explains co-author Javier Buceta of Lehigh University in Bethlehem, Pennsylvania, because cell neighbors exchange information. Knowing the typical shape of cells could help to diagnose dysfunction and to inform tissue engineering. The researchers are continuing their work, curious to discover whether scutoid cells exist across a diversity of other life forms. (Nature Communications)