September 27, 2012

Organs are not just a messy mash-up of cells. Their formation is carefully and elegantly orchestrated, with influences from both outside and inside of the cells. Today’s image is from a paper using micropatterned cell culture trickery to show how cell confinement affects epithelial morphogenesis.

During the development of many organs, epithelial morphogenesis transforms cells into sheets of epithelial cells with a functional lumen. These epithelial cells are polarized—one side of the cell faces the inside, or lumen, while the other side faces away from the organ. The process during which a cell becomes polarized relies on several cues, some of which are from the outside physical environment of the cell. Tissue rigidity, water tension, and cell confinement all participate in regulating cell shape and development. A recent paper describes how cell confinement affects lumen formation, a key part of epithelial organ morphogenesis. Rodríguez-Fraticelli and colleagues used surfaces with adhesive micropatterns to simulate cell confinement, and found that cell confinement limits actin contractility around the periphery of the cell, which in turn affects lumen formation. In addition, centrosome positioning is regulated by cell confinement. As seen in the images above, cells in low confinement (right) positioned their centrosomes toward the periphery of the micropatterned area (gray circles), while cells in high confinement (left, middle) positioned their centrosomes (green, arrowheads) toward the side where lumen formation would take place. Bottom row of images shows the side-view (z-stack) of the cells in the top row.

Alejo E. Rodríguez-Fraticelli, Muriel Auzan, Miguel A. Alonso, Michel Bornens, & Fernando Martín-Belmonte (2012). Cell confinement controls centrosome positioning and lumen initiation during epithelial morphogenesis originally published in the Journal of Cell Biology, 198 (6), 1011-1023 DOI: 10.1083/jcb.201203075