@article{14041, abstract = {Tissue morphogenesis and patterning during development involve the segregation of cell types. Segregation is driven by differential tissue surface tensions generated by cell types through controlling cell-cell contact formation by regulating adhesion and actomyosin contractility-based cellular cortical tensions. We use vertebrate tissue cell types and zebrafish germ layer progenitors as in vitro models of 3-dimensional heterotypic segregation and developed a quantitative analysis of their dynamics based on 3D time-lapse microscopy. We show that general inhibition of actomyosin contractility by the Rho kinase inhibitor Y27632 delays segregation. Cell type-specific inhibition of non-muscle myosin2 activity by overexpression of myosin assembly inhibitor S100A4 reduces tissue surface tension, manifested in decreased compaction during aggregation and inverted geometry observed during segregation. The same is observed when we express a constitutively active Rho kinase isoform to ubiquitously keep actomyosin contractility high at cell-cell and cell-medium interfaces and thus overriding the interface-specific regulation of cortical tensions. Tissue surface tension regulation can become an effective tool in tissue engineering.}, author = {Méhes, Elod and Mones, Enys and Varga, Máté and Zsigmond, Áron and Biri-Kovács, Beáta and Nyitray, László and Barone, Vanessa and Krens, Gabriel and Heisenberg, Carl-Philipp J and Vicsek, Tamás}, issn = {2399-3642}, journal = {Communications Biology}, publisher = {Springer Nature}, title = {{3D cell segregation geometry and dynamics are governed by tissue surface tension regulation}}, doi = {10.1038/s42003-023-05181-7}, volume = {6}, year = {2023}, } @article{676, abstract = {The segregation of different cell types into distinct tissues is a fundamental process in metazoan development. Differences in cell adhesion and cortex tension are commonly thought to drive cell sorting by regulating tissue surface tension (TST). However, the role that differential TST plays in cell segregation within the developing embryo is as yet unclear. Here, we have analyzed the role of differential TST for germ layer progenitor cell segregation during zebrafish gastrulation. Contrary to previous observations that differential TST drives germ layer progenitor cell segregation in vitro, we show that germ layers display indistinguishable TST within the gastrulating embryo, arguing against differential TST driving germ layer progenitor cell segregation in vivo. We further show that the osmolarity of the interstitial fluid (IF) is an important factor that influences germ layer TST in vivo, and that lower osmolarity of the IF compared with standard cell culture medium can explain why germ layers display differential TST in culture but not in vivo. Finally, we show that directed migration of mesendoderm progenitors is required for germ layer progenitor cell segregation and germ layer formation.}, author = {Krens, Gabriel and Veldhuis, Jim and Barone, Vanessa and Capek, Daniel and Maître, Jean-Léon and Brodland, Wayne and Heisenberg, Carl-Philipp J}, issn = {09501991}, journal = {Development}, number = {10}, pages = {1798 -- 1806}, publisher = {Company of Biologists}, title = {{Interstitial fluid osmolarity modulates the action of differential tissue surface tension in progenitor cell segregation during gastrulation}}, doi = {10.1242/dev.144964}, volume = {144}, year = {2017}, } @article{735, abstract = {Cell-cell contact formation constitutes an essential step in evolution, leading to the differentiation of specialized cell types. However, remarkably little is known about whether and how the interplay between contact formation and fate specification affects development. Here, we identify a positive feedback loop between cell-cell contact duration, morphogen signaling, and mesendoderm cell-fate specification during zebrafish gastrulation. We show that long-lasting cell-cell contacts enhance the competence of prechordal plate (ppl) progenitor cells to respond to Nodal signaling, required for ppl cell-fate specification. We further show that Nodal signaling promotes ppl cell-cell contact duration, generating a positive feedback loop between ppl cell-cell contact duration and cell-fate specification. Finally, by combining mathematical modeling and experimentation, we show that this feedback determines whether anterior axial mesendoderm cells become ppl or, instead, turn into endoderm. Thus, the interdependent activities of cell-cell signaling and contact formation control fate diversification within the developing embryo.}, author = {Barone, Vanessa and Lang, Moritz and Krens, Gabriel and Pradhan, Saurabh and Shamipour, Shayan and Sako, Keisuke and Sikora, Mateusz K and Guet, Calin C and Heisenberg, Carl-Philipp J}, issn = {15345807}, journal = {Developmental Cell}, number = {2}, pages = {198 -- 211}, publisher = {Cell Press}, title = {{An effective feedback loop between cell-cell contact duration and morphogen signaling determines cell fate}}, doi = {10.1016/j.devcel.2017.09.014}, volume = {43}, year = {2017}, } @article{946, abstract = {Roots navigate through soil integrating environmental signals to orient their growth. The Arabidopsis root is a widely used model for developmental, physiological and cell biological studies. Live imaging greatly aids these efforts, but the horizontal sample position and continuous root tip displacement present significant difficulties. Here, we develop a confocal microscope setup for vertical sample mounting and integrated directional illumination. We present TipTracker – a custom software for automatic tracking of diverse moving objects usable on various microscope setups. Combined, this enables observation of root tips growing along the natural gravity vector over prolonged periods of time, as well as the ability to induce rapid gravity or light stimulation. We also track migrating cells in the developing zebrafish embryo, demonstrating the utility of this system in the acquisition of high-resolution data sets of dynamic samples. We provide detailed descriptions of the tools enabling the easy implementation on other microscopes.}, author = {Von Wangenheim, Daniel and Hauschild, Robert and Fendrych, Matyas and Barone, Vanessa and Benková, Eva and Friml, Jirí}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Live tracking of moving samples in confocal microscopy for vertically grown roots}}, doi = {10.7554/eLife.26792}, volume = {6}, year = {2017}, } @phdthesis{961, abstract = {Cell-cell contact formation constitutes the first step in the emergence of multicellularity in evolution, thereby allowing the differentiation of specialized cell types. In metazoan development, cell-cell contact formation is thought to influence cell fate specification, and cell fate specification has been implicated in cell-cell contact formation. However, remarkably little is yet known about whether and how the interaction and feedback between cell-cell contact formation and cell fate specification affect development. Here we identify a positive feedback loop between cell-cell contact duration, morphogen signaling and mesendoderm cell fate specification during zebrafish gastrulation. We show that long lasting cell-cell contacts enhance the competence of prechordal plate (ppl) progenitor cells to respond to Nodal signaling, required for proper ppl cell fate specification. We further show that Nodal signalling romotes ppl cell-cell contact duration, thereby generating an effective positive feedback loop between ppl cell-cell contact duration and cell fate specification. Finally, by using a combination of theoretical modeling and experimentation, we show that this feedback loop determines whether anterior axial mesendoderm cells become ppl progenitors or, instead, turn into endoderm progenitors. Our findings reveal that the gene regulatory networks leading to cell fate diversification within the developing embryo are controlled by the interdependent activities of cell-cell signaling and contact formation.}, author = {Barone, Vanessa}, issn = {2663-337X}, pages = {109}, publisher = {Institute of Science and Technology Austria}, title = {{Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation}}, doi = {10.15479/AT:ISTA:th_825}, year = {2017}, } @article{1100, abstract = {During metazoan development, the temporal pattern of morphogen signaling is critical for organizing cell fates in space and time. Yet, tools for temporally controlling morphogen signaling within the embryo are still scarce. Here, we developed a photoactivatable Nodal receptor to determine how the temporal pattern of Nodal signaling affects cell fate specification during zebrafish gastrulation. By using this receptor to manipulate the duration of Nodal signaling in vivo by light, we show that extended Nodal signaling within the organizer promotes prechordal plate specification and suppresses endoderm differentiation. Endoderm differentiation is suppressed by extended Nodal signaling inducing expression of the transcriptional repressor goosecoid (gsc) in prechordal plate progenitors, which in turn restrains Nodal signaling from upregulating the endoderm differentiation gene sox17 within these cells. Thus, optogenetic manipulation of Nodal signaling identifies a critical role of Nodal signaling duration for organizer cell fate specification during gastrulation.}, author = {Sako, Keisuke and Pradhan, Saurabh and Barone, Vanessa and Inglés Prieto, Álvaro and Mueller, Patrick and Ruprecht, Verena and Capek, Daniel and Galande, Sanjeev and Janovjak, Harald L and Heisenberg, Carl-Philipp J}, journal = {Cell Reports}, number = {3}, pages = {866 -- 877}, publisher = {Cell Press}, title = {{Optogenetic control of nodal signaling reveals a temporal pattern of nodal signaling regulating cell fate specification during gastrulation}}, doi = {10.1016/j.celrep.2016.06.036}, volume = {16}, year = {2016}, } @article{1537, abstract = {3D amoeboid cell migration is central to many developmental and disease-related processes such as cancer metastasis. Here, we identify a unique prototypic amoeboid cell migration mode in early zebrafish embryos, termed stable-bleb migration. Stable-bleb cells display an invariant polarized balloon-like shape with exceptional migration speed and persistence. Progenitor cells can be reversibly transformed into stable-bleb cells irrespective of their primary fate and motile characteristics by increasing myosin II activity through biochemical or mechanical stimuli. Using a combination of theory and experiments, we show that, in stable-bleb cells, cortical contractility fluctuations trigger a stochastic switch into amoeboid motility, and a positive feedback between cortical flows and gradients in contractility maintains stable-bleb cell polarization. We further show that rearward cortical flows drive stable-bleb cell migration in various adhesive and non-adhesive environments, unraveling a highly versatile amoeboid migration phenotype.}, author = {Ruprecht, Verena and Wieser, Stefan and Callan Jones, Andrew and Smutny, Michael and Morita, Hitoshi and Sako, Keisuke and Barone, Vanessa and Ritsch Marte, Monika and Sixt, Michael K and Voituriez, Raphaël and Heisenberg, Carl-Philipp J}, journal = {Cell}, number = {4}, pages = {673 -- 685}, publisher = {Cell Press}, title = {{Cortical contractility triggers a stochastic switch to fast amoeboid cell motility}}, doi = {10.1016/j.cell.2015.01.008}, volume = {160}, year = {2015}, } @article{1912, abstract = {Kupffer's vesicle (KV) is the zebrafish organ of laterality, patterning the embryo along its left-right (LR) axis. Regional differences in cell shape within the lumen-lining KV epithelium are essential for its LR patterning function. However, the processes by which KV cells acquire their characteristic shapes are largely unknown. Here, we show that the notochord induces regional differences in cell shape within KV by triggering extracellular matrix (ECM) accumulation adjacent to anterior-dorsal (AD) regions of KV. This localized ECM deposition restricts apical expansion of lumen-lining epithelial cells in AD regions of KV during lumen growth. Our study provides mechanistic insight into the processes by which KV translates global embryonic patterning into regional cell shape differences required for its LR symmetry-breaking function.}, author = {Compagnon, Julien and Barone, Vanessa and Rajshekar, Srivarsha and Kottmeier, Rita and Pranjic-Ferscha, Kornelija and Behrndt, Martin and Heisenberg, Carl-Philipp J}, journal = {Developmental Cell}, number = {6}, pages = {774 -- 783}, publisher = {Cell Press}, title = {{The notochord breaks bilateral symmetry by controlling cell shapes in the Zebrafish laterality organ}}, doi = {10.1016/j.devcel.2014.11.003}, volume = {31}, year = {2014}, } @article{2926, abstract = {To fight infectious diseases, host immune defenses are employed at multiple levels. Sanitary behavior, such as pathogen avoidance and removal, acts as a first line of defense to prevent infection [1] before activation of the physiological immune system. Insect societies have evolved a wide range of collective hygiene measures and intensive health care toward pathogen-exposed group members [2]. One of the most common behaviors is allogrooming, in which nestmates remove infectious particles from the body surfaces of exposed individuals [3]. Here we show that, in invasive garden ants, grooming of fungus-exposed brood is effective beyond the sheer mechanical removal of fungal conidiospores; it also includes chemical disinfection through the application of poison produced by the ants themselves. Formic acid is the main active component of the poison. It inhibits fungal growth of conidiospores remaining on the brood surface after grooming and also those collected in the mouth of the grooming ant. This dual function is achieved by uptake of the poison droplet into the mouth through acidopore self-grooming and subsequent application onto the infectious brood via brood grooming. This extraordinary behavior extends the current understanding of grooming and the establishment of social immunity in insect societies.}, author = {Tragust, Simon and Mitteregger, Barbara and Barone, Vanessa and Konrad, Matthias and Ugelvig, Line V and Cremer, Sylvia}, journal = {Current Biology}, number = {1}, pages = {76 -- 82}, publisher = {Cell Press}, title = {{Ants disinfect fungus-exposed brood by oral uptake and spread of their poison}}, doi = {10.1016/j.cub.2012.11.034}, volume = {23}, year = {2013}, } @article{3246, abstract = {Visualizing and analyzing shape changes at various scales, ranging from single molecules to whole organisms, are essential for understanding complex morphogenetic processes, such as early embryonic development. Embryo morphogenesis relies on the interplay between different tissues, the properties of which are again determined by the interaction between their constituent cells. Cell interactions, on the other hand, are controlled by various molecules, such as signaling and adhesion molecules, which in order to exert their functions need to be spatiotemporally organized within and between the interacting cells. In this review, we will focus on the role of cell adhesion functioning at different scales to organize cell, tissue and embryo morphogenesis. We will specifically ask how the subcellular distribution of adhesion molecules controls the formation of cell-cell contacts, how cell-cell contacts determine tissue shape, and how tissue interactions regulate embryo morphogenesis.}, author = {Barone, Vanessa and Heisenberg, Carl-Philipp J}, journal = {Current Opinion in Cell Biology}, number = {1}, pages = {148 -- 153}, publisher = {Elsevier}, title = {{Cell adhesion in embryo morphogenesis}}, doi = {10.1016/j.ceb.2011.11.006}, volume = {24}, year = {2012}, } @misc{9757, abstract = {To fight infectious diseases, host immune defences are employed at multiple levels. Sanitary behaviour, such as pathogen avoidance and removal, acts as a first line of defence to prevent infection [1] before activation of the physiological immune system. Insect societies have evolved a wide range of collective hygiene measures and intensive health care towards pathogen-exposed group members [2]. One of the most common behaviours is allogrooming, in which nestmates remove infectious particles from the body surfaces of exposed individuals [3]. Here we show that, in invasive garden ants, grooming of fungus-exposed brood is effective beyond the sheer mechanical removal of fungal conidiospores as it also includes chemical disinfection through the application of poison produced by the ants themselves. Formic acid is the main active component of the poison. It inhibits fungal growth of conidiospores remaining on the brood surface after grooming and also those collected in the mouth of the grooming ant. This dual function is achieved by uptake of the poison droplet into the mouth through acidopore self-grooming and subsequent application onto the infectious brood via brood grooming. This extraordinary behaviour extends current understanding of grooming and the establishment of social immunity in insect societies.}, author = {Tragust, Simon and Mitteregger, Barbara and Barone, Vanessa and Konrad, Matthias and Ugelvig, Line V and Cremer, Sylvia}, publisher = {Dryad}, title = {{Data from: Ants disinfect fungus-exposed brood by oral uptake and spread of their poison}}, doi = {10.5061/dryad.61649}, year = {2012}, }