Laboratoire Matière et Systèmes Complexes

Tom Wyatt is currently doing his post-doc at MSC Lab. He will present his previous work, done during his PhD at University College London, and dedicated to the deformations (under both stretching and compression) of epithelia.

The idea of this seminar is that Tom can also share his experience concerning the choice of a post-doc. The feedback of other post-docs in the lab is also welcome to have a fruitful discussion.

Abstract : I will talk briefly about two projects carried out during my PhD which both involved the stretching and compression of simple mammalian tissues called epithelia. We are interested in how epithelia react to being deformed because a large portion of the structures which mammalian embryos create whilst they develop (tubes, glands, eye balls, teeth) are formed, in their earliest stages, via the bending and stretching of simple epithelial layers. And also because deformation of epithelia features in many normal adult physiological processes such as breathing, growing and frowning.

I’ll first present our results on the effect of stretch on cell division in epithelia. We found that cells were able to align their divisions according to the direction of uniaxial stretch or perpendicular to uniaxial compression. We showed that this was achieved through cells measuring their own shape, rather than by detecting a stress signal in the tissue.

Secondly, I’ll present some work on the buckling of epithelia following large, rapid compressions. We found that epithelia can rapidly reabsorb buckles so as to return to a flat configuration and that this is achieved by establishing a resting pre-tension. This process has a well-defined limit at a strain of -0.35, so that stable buckles can form in tissues which are compressed by greater amounts. Finally we found that tissues can change this threshold by tuning tissue stiffness and pre-tension via regulation of the actomyosin cytoskeleton.

Jeudi 21 Février 2019 à 12h30 en salle 454A.