Séminaire externe - Claire Leclech (Ecole Polytechnique)

Adherent cells in vivo reside on extracellular matrices (ECMs) that possess a topographical organization at different scales. Various types of engineered microstructured substrates have been developed to study the impact of basal topographical cues on cell behavior in vitro. Amongst them, microgrooves mimicking the anisotropic organization of the ECM have been shown to align and elongate different cell types. However, how cells detect and respond to microgrooves remains unclear. I am investigating these questions using vascular endothelial cells (ECs), which in vivo form a monolayer lining the inner surfaces of blood vessels.

Using microgroove substrates, I have demonstrated the major influence of substrate topography on ECs at different scales, from single cells to collective behavior in monolayers. At the single cell scale, ECs cultured on parallel arrays of microgrooves (width = 5 µm, depth = 1 to 5 µm) are elongated, and they align and migrate in the groove direction. Interestingly, these changes in cell shape on microgrooves are also associated with significant vertical (Z) deformations of the cells and their nuclei which can be completely confined within a groove. At the monolayer scale, I have described on microgrooves the emergence of a specific pattern of collective movement in the form of periodic antiparallel cell streams.

In this seminar, I will present in more details these various experimental observations on EC interactions with microgroove substrates and will discuss some ideas on the use of physical concepts and models to help understand these interactions.