Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 6: Poster I
BP 6.49: Poster
Montag, 1. April 2019, 17:30–19:30, Poster B2
A muscle cell seen as active matter: Heterogeneities and dynamic instabilities in sarcomere contraction of cardiomyocytes — •Daniel Härtter1, Wolfram-Hubertus Zimmermann2, and Christoph F. Schmidt1,3 — 1Drittes Physikalisches Institut - Biophysik, Georg-August-Universität Göttingen — 2Institut für Pharmakologie, Universitätsmedizin, Georg-August-Universität Göttingen — 3Department of Physics, Duke University, USA
Cardiac muscle contraction involves highly coordinated dynamics, from the level of the myosin motors on the length-scale of nanometers to that of the whole organ. Many features of muscle contraction, however, emerge on the mesoscopic length scale of (half-)sarcomeres, the basic contractile unit of muscles consisting of mechanically coupled molecular motors. Basic theories of collective molecular motor dynamics predict emergent phenomena such as dynamic instabilities and spontaneous oscillatory motion due to non-monotonic force-velocity relations. On the next level of the hierarchy, when half-sarcomeres are coupled in series and in parallel, even richer emergent dynamics are expected. So far, inter-sarcomere dynamics have not been studied systematically. We have imaged sarcomere dynamics in individual stem-cell-derived cardiomyocytes with endogenous fluorescent labeling of z-bands introduced by CRISPR/Cas9, and have observed that mechanical competition leads to sarcomere de-coherence and complex dynamic heterogeneity. We have modelled the phenomena with a dynamic myofibril model of multiple heterogeneous elements with non-monotonic force-velocity relations from a complex systems / active matter perspective.