Supplementary MaterialsReporting Overview

Supplementary MaterialsReporting Overview. tension reveals a tensional plateau over several-fold areal strains. These extreme tissue strains are accommodated by highly heterogeneous cellular strains, in seeming contradiction with the measured tensional uniformity. This phenomenology is reminiscent of superelasticity, a behavior generally attributed to microscopic material instabilities in metal alloys. We show that this instability is triggered in epithelial cells by a stretch-induced dilution of the actin cortex and rescued by the intermediate filament network. Our study unveils a new type of mechanical behavior -active superelasticity- that enables epithelial sheets to sustain extreme stretching under constant tension. Epithelial tissues enable key physiological functions, including morphogenesis, transport, secretion and absorption1. To perform these functions, epithelia often adopt a three-dimensional architecture consisting of a curved cellular sheet that encloses a pressurized fluid-filled lumen2,3. The loss of this three-dimensional architecture is associated with developmental defects, inflammatory conditions, and cancer4,5. The acquisition of a three-dimensional AVL-292 benzenesulfonate shape by epithelial sheets requires a limited control of mobile deformation, mechanised tension, and luminal pressure. How these mechanised factors are tuned to sculpt three-dimensional epithelia can be unfamiliar collectively, however, because current ways to map epithelial technicians are limited to two-dimensional levels seeded on a set substrate6 mainly, 7 or standing up between cantilevers5 freely. Here we record immediate measurements of grip, tension, pressure and deformation in three-dimensional epithelial monolayers of managed decoration. These measurements establish that epithelial monolayers exhibit active superelasticity, an unanticipated mechanical behavior that enables extreme deformations at nearly constant tension. Micropatterning epithelial domes To shape epithelial monolayers in 3D, we used transmural pressure as morphogenetic driving force. We seeded MDCK cells on a soft PDMS substrate that PRP9 was homogeneously coated with fibronectin except for micropatterned nonadhesive areas of precise geometry (Fig. 1a). A few hours after seeding, cells covered the adherent regions of the gel and, with time, they invaded the non-adherent areas8,9. Since MDCK cells are known to actively pump osmolites in the apico-basal AVL-292 benzenesulfonate direction10,11, we reasoned that fluid pressure should build-up in the interstitial space between cells and the impermeable substrate, leading to tissue delamination from the substrate in the non-adherent regions. In agreement with this rationale, we observed the AVL-292 benzenesulfonate spontaneous formation of multicellular epithelial domes closely following micropatterned shapes such as circles, rectangles and stars (Fig. 1b-e, Extended Data fig. 1a-d). In contrast to spontaneous doming by delamination10,11, control of dome footprint gave us access to large variations in dome aspect ratio (Fig. 1c-e). Open in a separate window Figure 1 Generation of epithelial domes of controlled size and shape.a, Scheme of the process of dome formation. b, Top view of an array of 1515 epithelial domes (n=10). Scale bar, 1 mm. c-e, Confocal x-y, y-z and x-z sections of MDCK-LifeAct epithelial domes with a round basal form and differing AVL-292 benzenesulfonate spacing (n=10). Size pub, 100 m. Dimension of AVL-292 benzenesulfonate dome technicians To measure dome technicians, we centered on round patterns and applied 3D grip microscopy to look for the three the different parts of tractions at the top of PDMS substrate (Fig. 2a,b). Tractions in adherent areas showed huge fluctuations with out a very clear spatial design (Fig. 2b). In comparison, non-adherent areas exhibited organized regular and consistent adverse tractions that indented the substrate nearly. In a slim annular region in the margin from the dome footprint, the traction vector exhibited an optimistic normal component pulling the substrate upwards consistently. These observations, combined with the morphology from the domes, founded how the lumen is at an ongoing condition of hydrostatic pressure, and that.