Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 55: Cell Migration and Contraction

BP 55.7: Talk

Thursday, March 23, 2017, 17:00–17:15, HÜL 386

Cell-Type Specific Mechano-Sensing altered by Blebbistatin — •Galina Kudryasheva and Florian Rehfeldt — III. Physikalisches Institut Friedrich-Hund-Platz 1 37077 Göttingen Germany

Cells sense the stiffness of their surrounding with contractile acto-myosin stress fibers through focal adhesions and react to such physical stimuli by altering their bio-chemical pathways. Especially striking is the mechano-guided differentiation of human mesenchymal stem cells (hMSCs) [Engler et al. Cell (2006)]. While the entire differentiation process can take several days up to weeks, the structure and dynamics of stress fibers can be used as an early morphological marker and theoretically modelled using classical mechanics with an active spring model [Zemel et al. Nat. Phys. (2010)]. We use this approach and the theoretical model to analyze the mechanical cell-matrix interactions of hMSCs and several types of differentiated cells. Using immunofluorescence we visualized stress fibers and analyzed the cytoskeletal morphology [Eltzner et al. PLoS One (2015)] of cells cultured on elastic substrates (E from 1kPa to 130 kPa). Analyzing cell area and cytoskeletal order parameter S we could assign an effective cellular stiffness that shows distinct differences during the differentiation process and for different cell types. 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 (NMM II) inhibitor blebbistatin alters cellular mechano-sensitivity by facilitating cell spreading on soft substrates through relaxing the cellular acto-myosin cortex, but not on stiff substrates.