Berlin 2018 – scientific programme

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BP: Fachverband Biologische Physik

BP 10: Postersession II

BP 10.25: Poster

Monday, March 12, 2018, 17:30–19:30, Poster C

Cell-Type Specific Mechano-Sensing Altered by Blebbistatin — •Galina Kudryasheva and Florian Rehfeldt — Göttingen University

Cells sense the mechanical properties of their surroundings with contractile acto-myosin stress fibers through focal adhesions and react to such physical stimuli by distinct pattern formation of their cytoskeleton and by altering their bio-chemical pathways. Especially striking is the mechano-guided differentiation of human mesenchymal stem cells (hMSCs). The structure and dynamics of acto-myosin stress fibers is used as an early morphological marker and theoretically modelled using classical mechanics with an active spring model. We use this approach to elucidate the mechanical cell-matrix interactions of hMSCs and several types of differentiated cells. Employing immuno-fluorescence microscopy we visualize stress fibers and analyze the global morphology of the cells cultured on elastic substrates (E_m from 1 kPa to 130 kPa). Applying the theoretical model to our experimentally obtained cell spread area we extract an effective Young's modulus of the cell (E_c). We demonstrate that E_c changes during hMSCs differentiation process and varies for different cell lines. Our experiments show that the mechanical susceptibility is cell type specific and dependent on acto-myosin contractility. Interestingly, addition of the non-muscle myosin II (NMMII) inhibitor blebbistatin at low concentrations (c = 12.5 and 25 uM) softens the cells (reduces the effective Young's modulus E_c) and facilitates cell spreading only on soft substrates through relaxing the cellular acto-myosin cortex.