Biophysical Society Thematic Meeting| Aussois 2019

Biology and Physics Confront Cell-Cell Adhesion

Monday Speaker Abstracts

TENSILE STRENGTH VS. SHEAR STRESS – AN APPROACH TO MEASURE INTERNAL TENSIONS BETWEEN CELL-CELL JUNCTIONS Julia Eckert 1 ; Luca Giomi 1 ; Thomas Schmidt 1 ; 1 Physics of Life Processes, Leiden Institute of Physics, Leiden University, Leiden, The Netherlands Cell-cell junctions and cell-extracellular-matrix adhesions are important for communication and coordination within tissues. Thereby, cells sense and apply different mechanical types of stress, for example during migration of cell clusters, tissue expansion or tissue compression. During all these cues, internal tensions act at the interface, of cell-matrix and of cell-cell junctions. Where stress at the cellmatrix interface have been extensively studied, cellular stress and forces at the cell-cell junctions in tissue are less well characterized. We have developed a methodology to measure both the external stress of cells towards the matrix and the internal stress between cells. Our methodology allows us to distinguish and to compare tensile vs shear stress on cell-cell junctions. Based on micropillar arrays for cell traction force measurements, we produced PDMS micropillar array-blocks, of size resembling that of individual cells, separated by micrometer-spacings. Cells adhere to individual blocks and are allowed to connect over the spacings. A controlled stretch allows us to change either the distance or the parallel position of the blocks with respect to each other. Thereby we are able to apply pure tensile or pure shear stress on the cell-cell junctions up to the point where they break. Our new methodology opens the way to study the influence of mechanical stress on cell-cell adhesions and to measure directly the internal tension between involved junctions of different types of cells.

INTRINSIC CELL CONTRACTION IS ESSENTIAL FOR JUNCTION CONFIGURATION AND STABILIZATION Vania M Braga 1 ; 1 Imperial College London, Faculty of Medicine, London, United Kingdom

Cell-cell adhesion plays an essential role in the determination of cell shape and function during development and adult life, including tissue integrity, morphogenesis and homeostasis. Dynamic regulation of cadherin-dependent cell-cell adhesion modulates important cellular processes such as contractility, distribution of different polarity markers and specific localization of signalling platforms. Conversely, tumour de-differentiation in epithelial tissues is accompanied by disruption of cell-cell contacts and re-writing of signalling to drive uncontrolled proliferation and migration. Here I discuss the interplay between intrinsic cellular contraction and the shape and strength of cadherin contacts, and how this cross-talk impact on the disruption of junctions and epithelial architecture by oncogenic stimulation

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