When an embryo develops, tissues turn into complex three-dimensional shapes that lead to organs. Epithelial cells are the building blocks of this process, which, for example, forms the outer skin layer. They also line the blood vessels and organs of all animals.
These cells are packed tightly together. To account for the curvature that occurs during embryonic development, it has been assumed that epithelial cells assume either columnar or bottle-like shapes.
However, a group of scientists dug deeper into this phenomenon, discovering a new geometric shape.
They found that epithelial cells assume a previously undescribed shape during tissue diffraction, allowing cells to minimize energy consumption and maximize packaging stability. The results of the team are published in Nature Communications in an article entitled "Scutoids are a geometric solution for the three-dimensional packing of epithelia".
The study is the result of collaboration between the United States and the European Union between the teams of Luis M. Escudero (University of Seville, Spain) and Javier Buceta (Lehigh University, USA). Pedro Gomez-Galvez and Pablo Vicente-Munuera are the first authors of this work, including scientists from the Andalusian Center for Developmental Biology and the Severo Ochoa Center for Molecular Biology.
Buceta and his colleagues first made the discovery through computer modeling using Voronoi diagrams, a tool used in a number of areas to understand geometric organization.
"During the modeling process, the results we saw were strange," says Buceta. "Our model predicted that with increasing curvature of the tissue, columns and bottle shapes are not the only forms that cells can develop, to our surprise, the extra form did not have a name in mathematics! Normally, there is no way to name a new shape.
The group has called the new shape "Skutoid" because of its similarity to the scutellum ̵
To verify the predictions of the model, the group investigated the three-dimensional packaging of various tissues in different animals. The experimental data confirmed that epithelial cells assume shapes and three-dimensional packing motifs similar to those predicted by the computer model.
Using biophysical approaches, the team argues that the scutoids stabilize the three-dimensional packing and render it energetically efficient. As Buceta puts it: "We have unlocked the solution of nature for efficient epithelial flexion."
Their findings could pave the way for understanding the three-dimensional organization of epithelial organs and leading to advances in tissue engineering.
"In addition to this fundamental aspect of morphogenesis," they write, "the ability to construct tissues and organs in the future is based on the ability to understand and then control the 3D organization of cells."
Adds Buceta: "If you are looking for artificial organs, for example, this discovery could help you build a framework that stimulates this type of cell packing and mimics the natural way to efficiently develop tissue."  Story Source:
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