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From cells to tissues: physical modelling of the collective behaviour of embryonic cells

Abstract : To understand how cellular mechanical properties act on the level of a tissue, where they are implied in morphogenesis, it has been proposed that cells act as soap bubbles or molecules in a liquid. We test these analogies between tissues and physical systems with a computational model, in collaboration with experimentalists.

In the retina of Drosophila, the packing of cells has been compared to soap bubble packing. We find that the resemblance is not due to the physical resemblance of cells and bubbles, but to a similar organisation on the collective level: cells in a tissue tile the space, like bubbles in a foam, thereby influencing each other's shapes.

The spontaneous sorting of cells of different types has been compared to the demixing of liquids. While in liquids this behaviour is due to the attraction between molecules, we find that in aggregates of zebrafish germlayer cells differential contraction of the cytoskeleton plays a role as well.

Compression of an aggregate of cells has been analysed as if the aggregate behaved as a liquid drop, where only the surface tension determines its properties. However, individual cells in the aggregate deform and rearrange, and solid-like stresses inside the aggregate co-determine its shape and forces.

The widely used physical analogies prove thus to be incomplete, but interesting. We propose a distinctive description, in which an aggregate or tissue is a collection of closely packed living cells that change shape and rearrange. This approach allows to study how cell adhesion, cortical tension and the cellular fluctuations govern the behaviour on the collective level, and on morphogenesis.
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https://tel.archives-ouvertes.fr/tel-00346418
Contributor : Jos Käfer <>
Submitted on : Thursday, December 11, 2008 - 3:42:31 PM
Last modification on : Thursday, October 10, 2019 - 11:42:04 AM
Long-term archiving on: : Thursday, October 11, 2012 - 1:25:21 PM

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Jos Käfer. From cells to tissues: physical modelling of the collective behaviour of embryonic cells. Biological Physics [physics.bio-ph]. Université Joseph-Fourier - Grenoble I, 2008. English. ⟨tel-00346418⟩

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