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The spatio-temporal dynamics of cell membranes deformations and cell migration

Angélique Stéphanou 1
1 DynaCell
TIMC - Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525
Abstract : The thesis concerns the study of cell deformations through 2 complementary approaches, experimental and theoretical motivated by the demonstration from previous works of the existence of a certain auto-organization of the deformation patterns for round-shaped cells. We have chosen to study L929 fibroblasts.which exhibit a more complex organization of the actin cytoskeleton. Experimental characterization has been performed from videomicroscopic image sequences. The morphodynamical data of the cells have been extracted from the images with 2 methods: (i) a segmentation of the cell boundaries and (ii) an optical flow method. The results show that the cells exhibit mainly symmetrical morphologies dynamically characterized by a synchronized and periodical pulsating movement. Theoretically, we have been interested in a cytomechanical model of deformations based on the poly/depolymerization dynamic of actin in relation to the mechanical interactions between the membrane and the cytoskeleton.The simulations have demonstrated the ability of the model to generate qualitatively pulsating states such as those observed. Two extensions of the model were proposed in order to take into account: (i) cell-cell interactions characterized by the inhibition of the cell protrusive activity and (ii) cell migration by chemotaxis by acting in both cases on the mechanical properties of the membrane and the cortex. Realistic behaviours of the cell could be simulated. Finally, a new formulation of the initial model has been proposed to model more the long membrane extensions of the fibroblasts. The work realized allows us in particular, to propose the possibility to use the morphodynamical parameters as criteria to identify the cell phenotypes.
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Theses
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https://tel.archives-ouvertes.fr/tel-00004593
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Submitted on : Monday, February 9, 2004 - 10:28:02 AM
Last modification on : Thursday, November 19, 2020 - 7:30:07 PM
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Angélique Stéphanou. The spatio-temporal dynamics of cell membranes deformations and cell migration. Modeling and Simulation. Université Joseph-Fourier - Grenoble I, 2002. English. ⟨tel-00004593⟩

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