Résumé
The objective of this work is to propose both a mechanical model and a numerical method devoted to the cytoskeleton (CSK) form-finding, resulting from its structuration during cell adhesion and spreading. Indeed, it is now well admitted that cell mechanics depends closely on its CSK architecture. Thus, several structural models including tensegrity models have been developed, but the observed topological and geometrical complexities of the CSK network lead to difficulties for choosing a realistic structure. The presented method allows determining such complex geometries and the associated forces supported by the different CSK-filaments of adherent cells. Presently, an adherent cell is modeled by using a granular medium with rigid grains (associated to some CSK cross-linkers) connected by at-distance mechanical interaction forces (associated to the CSK filaments). Spreading process is simulated by considering microtubules growing from the centrosome towards transmembrane integrin receptors. During this process, the shape of the cell changes, resulting in a structure with traction and compression forces, that ensure its mechanical equilibrium in interaction with the extracellular matrix (Fig. 1). This leads to a realistic compressive microtubule-like network (Fig. 2) and an associated tensile actin-like network (Fig. 3). The obtained results highlights basal higher tensions while the less one appear on the apical face, consistently with in vivo distribution of strong stress fibers and of thin actin cortex. This approach may provide significant information for developing a mechanical model of the CSK structure with its spatial distribution of initial stresses, which could be applied to future studies of adherent cell mechanics.