Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 16: Posters: Cell adhesion, mechanics and migration
BP 16.31: Poster
Monday, March 16, 2015, 17:30–19:30, Poster A
Model analysis of P-Selectin-mediated leukocyte rolling — •Mats Moskopp1, Andreas Deussen1, Triantafyllos Chavakis2, and Peter Dieterich1 — 1Institut für Physiologie, TU Dresden, Germany — 2Klinische Pathobiochemie, TU Dresden, Germany
Invasion of leukocytes from the blood stream into tissue proceeds as coordinated sequence called leukocyte adhesion cascade and is indispensable for an efficient immune response. Numerous proteins realize interactions between leukocytes and vessel covering endothelial cells allowing rolling, adhesion, crawling and transmigration towards the tissue. In this study we observe P-Selectin-mediated rolling of THP1 myelomyonocytic cells in flow chambers where coating densities of P-Selectin are varied. Cell contours are extracted automatically by image-segmentation. The resulting positions of THP1 cells show a mean drift superimposed by intermittent fluctuations. Assuming that these fluctuations result from the properties of the bonds allows to assess their biomechanical properties. Therefore, we construct a simplified biomechanical model incorporating coupling to fluid shear stress, viscoelastic behavior of bonds, force-dependent rupture kinetics, and variations of receptor and ligand densities. Simulations of artificial position data are performed to extract the corresponding biomechanical parameters with Bayesian data analysis. This approach unveils the possibilities and limitations of parameter extraction from position curves and is further applied to experimental data. In summary, the combination of experiments and modeling allows the estimation of biomechanical properties at the nano-scale from observations of the whole cell.