@misc{MerksSwinarskiMeyeretal.2018, author = {Merks, Anne Margarete and Swinarski, Marie and Meyer, Alexander Matthias and M{\"u}ller, Nicola Victoria and {\"O}zcan, Ismail and Donat, Stefan and Burger, Alexa and Gilbert, Stephen and Mosimann, Christian and Abdelilah-Seyfried, Salim and Pan{\´a}kov{\´a}, Daniela}, title = {Planar cell polarity signalling coordinates heart tube remodelling through tissue-scale polarisation of actomyosin activity}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {849}, issn = {1866-8372}, doi = {10.25932/publishup-42702}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427026}, pages = {17}, year = {2018}, abstract = {Development of a multiple-chambered heart from the linear heart tube is inherently linked to cardiac looping. Although many molecular factors regulating the process of cardiac chamber ballooning have been identified, the cellular mechanisms underlying the chamber formation remain unclear. Here, we demonstrate that cardiac chambers remodel by cell neighbour exchange of cardiomyocytes guided by the planar cell polarity (PCP) pathway triggered by two non-canonical Wnt ligands, Wnt5b and Wnt11. We find that PCP signalling coordinates the localisation of actomyosin activity, and thus the efficiency of cell neighbour exchange. On a tissue-scale, PCP signalling planar-polarises tissue tension by restricting the actomyosin contractility to the apical membranes of outflow tract cells. The tissue-scale polarisation of actomyosin contractility is required for cardiac looping that occurs concurrently with chamber ballooning. Taken together, our data reveal that instructive PCP signals couple cardiac chamber expansion with cardiac looping through the organ-scale polarisation of actomyosin-based tissue tension.}, language = {en} } @article{KruegerGengeBrauneWalteretal.2018, author = {Kr{\"u}ger-Genge, A. and Braune, S. and Walter, M. and Krengel, M. and Kratz, K. and K{\"u}pper, J. H. and Lendlein, Andreas and Jung, Friedrich}, title = {Influence of different surface treatments of poly(n-butyl acrylate) networks on fibroblasts adhesion, morphology and viability}, series = {Clinical hemorheology and microcirculation : blood flow and vessels}, volume = {69}, journal = {Clinical hemorheology and microcirculation : blood flow and vessels}, number = {1-2}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1386-0291}, doi = {10.3233/CH-189130}, pages = {305 -- 316}, year = {2018}, abstract = {BACKGROUND: Physical and chemical characteristics of implant materials determine the fate of long-term cardiovascular devices. However, there is still a lack of fundamental understanding of the molecular mechanisms occurring in the material-tissue interphase. In a previous study, soft covalently crosslinked poly(n-butyl acrylate) networks (cPnBA) were introduced as sterilizable, non-toxic and immuno-compatible biomaterials with mechanical properties adjustable to blood vessels. Here we study the influence of different surface treatments in particular oxygen plasma modification and fibrinogen deposition as well as a combinatorial approach on the adhesion and viability of fibroblasts. RESULTS: Compared to non-treated cPnBAs the advancing water-contact angles were found to be reduced after all surface modifications (p<0.05, each), while lowest values were observed after the combined surface treatment (OPT+FIB). The latter differed significantly from the single OPT and FIB. The number of adherent fibroblasts and their adherence behavior differed on both pristine cPnBA networks. The fibroblast density on cPnBA04 was 743 +/- 434 cells. mm(-2), was about 6.5 times higher than on cPnBA73 with 115 +/- 73 cells. mm(-2). On cPnBA04 about 20\% of the cells were visible as very small, round and buckled cells while all other cells were in a migrating status. On cPnBA73, nearly 50\% of fibroblasts were visible as very small, round and buckled cells. The surface functionalization either using oxygen plasma treatment or fibrinogen coating led to a significant increase of adherent fibroblasts, particularly the combination of both techniques, for both cPnBA networks. It is noteworthy to mention that the fibrinogen coating overruled the characteristics of the pristine surfaces; here, the fibroblast densities after seeding were identical for both cPnBAnetworks. Thus, the binding rather depended on the fibrinogen coating than on the substrate characteristics anymore. While the integrity of the fibroblasts membrane was comparable for both polymers, the MTS tests showed a decreased metabolic activity of the fibroblasts on cPnBA. CONCLUSION: The applied surface treatments of cPnBA successfully improved the adhesion of viable fibroblasts. Under resting conditions as well as after shearing the highest fibroblast densities were found on surfaces with combined post-treatment.}, language = {en} } @misc{AlonsoStangeBeta2018, author = {Alonso, Sergio and Stange, Maike and Beta, Carsten}, title = {Modeling random crawling, membrane deformation and intracellular polarity of motile amoeboid cells}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {1014}, issn = {1866-8372}, doi = {10.25932/publishup-45974}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459745}, pages = {24}, year = {2018}, abstract = {Amoeboid movement is one of the most widespread forms of cell motility that plays a key role in numerous biological contexts. While many aspects of this process are well investigated, the large cell-to-cell variability in the motile characteristics of an otherwise uniform population remains an open question that was largely ignored by previous models. In this article, we present a mathematical model of amoeboid motility that combines noisy bistable kinetics with a dynamic phase field for the cell shape. To capture cell-to-cell variability, we introduce a single parameter for tuning the balance between polarity formation and intracellular noise. We compare numerical simulations of our model to experiments with the social amoeba Dictyostelium discoideum. Despite the simple structure of our model, we found close agreement with the experimental results for the center-of-mass motion as well as for the evolution of the cell shape and the overall intracellular patterns. We thus conjecture that the building blocks of our model capture essential features of amoeboid motility and may serve as a starting point for more detailed descriptions of cell motion in chemical gradients and confined environments.}, language = {en} }