BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:"\;Mechanical instabilities of epithelial tissues” - Dr Edou ard Hannezo (University of Cambridge) DTSTART:20141009T110000Z DTEND:20141009T120000Z UID:TALK55189@talks.cam.ac.uk CONTACT:Salvatore Tesoro DESCRIPTION: We propose a minimal theoretical model of epithelial shape in 3D\, based on cell adhesion and actomyosin contractility\, which describe s the various shapes of epithelial cells and the bending and buckling of e pithelial sheets\, as well as the relative stability of cellular tubes and spheres. We show that\, to understand these processes\, a full 3D descrip tion of the cells is needed\, but that simple scaling laws can still be de rived. The morphologies observed in vivo can be understood as stable point s of mechanical equations and the transitions between them are either cont inuous or discontinuous. We then focus on epithelial sheet bending\, a ubi quitous morphogenetic process. We calculate the curvature of an epithelium as a function of actin belt tension as well as of cell–cell and and cel l–substrate tension.\n\nSecondly\, we incorporate in our model the stres ses arising from cell division and death. When tissues grow in constrained environments\, buckling instabilities are gener- ically expected\, and we show that a simple biomechanical model can explain a wide variety of biol ogical shapes\, such as the intestinal wall or pathologies of biological t ubes such as arteries and trachea.\n\nWe then apply these theories to the concrete example of the development of the Drosophila trachea\, in collabo ration with Bo Dong and Shigeo Hayashi (RIKEN Institute\, Japan). Our fin dings demonstrate a mechanical role for the extracellular matrix and sugge st that the interaction of the apical membrane and an elastic aECM determi nes the final morphology of biological tubes independent of cell shape. LOCATION:TCM Seminar room\, 530 Mott building END:VEVENT END:VCALENDAR