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Martial Balland - Cell dipole behavior revealed by ECM geometry

Speaker : Martial Balland, Laboratoire interdisciplinaire de Physique Université Joseph Fourier (Grenoble 1)

When : Wednesday 2nd april at 11 am

Where : Salle CO23 (grande salle de réunions du CBP rez-de-chaussée LR6)

Title : Cell dipole behavior revealed by ECM geometry

Within living tissue, cells adopt and maintain reproducible shapes while they are submitted to external perturbations. This process is fundamental for tissue homeostasis and strongly relies on the bi-directional coupling between forces that are both sensed and exerted at the cell extracellular matrix (ECM) interface. The knowledge of how cell maintain a constant shape while they are submitted to external ECM stimuli should provide useful information to the field of tissue engineering. In this study, we control cells internal cytoskeletal organization by using highly resolved soft substrate micropatterns [1] that make it possible to define the ECM geometry at the sub-cellular level while keeping the overall cell envelope unchanged. In the following, we have investigated how one can act on the cytoskeleton architecture by designing the ECM geometry at the sub-cellular scale, while, at the same time, monitoring how cell generated forces redistribute and adapt to modification in the cytoskeletal architecture. This approach allowed us to untangle the effect of cell shape and area from that of cytoskeletal organization on the magnitude and localization of traction forces. Our results strongly suggest that cells are able to sense its adhesive environment and integrate this information at the whole cell level to organize its internal architecture. We also demonstrate here that a significant degree of polarization [2] can be induced by the ECM properties. We believe these findings to have important consequences for the understanding of tissue formation and the mechanisms of cells orientation in a tissue.

Force Orientation Map (A/)reveal actin organization (B/) of MEF cells plated on a arrow shaped fibronectin coated micropattern from the analysis of force fields obtained by Patterned Traction Cytometry (scale bar 7μm)

[1] Tseng Q, Wang I, Duchemin-Pelletier E, Azioune A, Carpi N, Gao J, Filhol O, Piel M, Théry M, Balland M, A new micropatterning method of soft substrates reveals that different tumorigenic signals can promote or reduce cell contraction levels, Lab Chip. 2011 Jul 7 ;11(13):2231-40

[2] Prager-Khoutorsky M, Lichtenstein A, Krishnan R, Rajendran K, Mayo A, Kam Z, Geiger B, Bershadsky AD., Fibroblast polarization is a matrix-rigidity-dependent process controlled by focal adhesion mechanosensing, Nat. Cell Biol. 2011 Nov. 13 ;13(12):1457-65