The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Sandrine Etiennemanneville - One of the best experts on this subject based on the ideXlab platform.
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intermediate filaments control collective migration by restricting traction forces and sustaining Cell Cell contacts
bioRxiv, 2018Co-Authors: Chiara De Pascalis, Carlos Perezgonzalez, Shailaja Seetharaman, Batiste Boeda, Benoit Vianay, Mithila Burute, Cecile Leduc, Nicolas Borghi, Xavier Trepat, Sandrine EtiennemannevilleAbstract:Mesenchymal Cell migration relies on the coordinated regulation of the actin and microtubule networks which participate in polarised Cell protrusion, adhesion and contraction. During collective migration, most of the traction forces are generated by the acto-myosin network linked to focal adhesions at the front of leader Cells, which transmit these pulling forces to the followers. Here, using an in vitro wound healing assay to induce polarisation and collective directed migration of primary astrocytes, we show that the intermediate filament (IF) network composed of vimentin, GFAP and nestin contributes to directed collective movement by controlling the distribution of forces in the Migrating Cell monolayer. Together with the cytoskeletal linker plectin, these IFs control the organisation and dynamics of the acto-myosin network, promoting the actin-driven treadmilling of adherens junctions, thereby facilitating the polarisation of leader Cells. Independently of their effect on adherens junctions, IFs influence the dynamics and localisation of focal adhesions and limit their mechanical coupling to the acto-myosin network. We thus conclude that IFs promote collective directed migration by restricting the generation of traction forces to the front of leader Cells, preventing aberrant tractions in the followers and by contributing to the maintenance of lateral Cell-Cell interactions.
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adherens junction treadmilling during collective migration
Nature Cell Biology, 2014Co-Authors: Florent Peglion, Flora Llense, Sandrine EtiennemannevilleAbstract:Collective Cell migration is essential for both physiological and pathological processes. Adherens junctions (AJs) maintain the integrity of the Migrating Cell group and promote Cell coordination while allowing Cellular rearrangements. Here, we show that AJs undergo a continuous treadmilling along the lateral sides of adjacent leading Cells. The treadmilling is driven by an actin-dependent rearward movement of AJs and is supported by the polarized recycling of N-cadherin. N-cadherin is mainly internalized at the Cell rear and then recycled to the leading edge where it accumulates before being incorporated into forming AJs at the front of lateral Cell-Cell contacts. The polarized dynamics of AJs is controlled by a front-to-rear gradient of p120-catenin phosphorylation, which regulates polarized trafficking of N-cadherin. Perturbation of the GSK3-dependent phosphorylation of p120-catenin impacts on the stability of AJs, and the polarity and speed of leading Cells during collective migration.
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in vitro assay of primary astrocyte migration as a tool to study rho gtpase function in Cell polarization
Methods in Enzymology, 2006Co-Authors: Sandrine EtiennemannevilleAbstract:Rho GTPases are key players in Cell migration. The contribution of Rho, Rac, and Cdc42 to the regulation of the actin and microtubule cytoskeletons is essential for membrane protrusion and Cell retraction (Etienne-Manneville and Hall, 2002). The polarization of these protrusive and retracting activities in a Migrating Cell is also under the control of Rho GTPases, in particular Cdc42 (Nobes and Hall, 1999). In vitro study of Cell migration has shown that Cdc42 activity is required for polarized Cell migration in several Cell types, including fibroblasts, neutrophils, macrophages, and astrocytes (Allen et al., 1998; Etienne-Manneville, 2004; Etienne-Manneville and Hall, 2001; Palazzo et al., 2001; Srinivasan et al., 2003). Using scratch-induced migration assay, we have previously used primary astrocytes as a tool to study the molecular mechanisms controlling Cell polarization at the onset of migration (Etienne-Manneville and Hall, 2001, 2003). On scratching of the monolayer, astrocytes polarize perpendicularly to the scratch to migrate and close the wound. Astrocyte polarization is characterized by the formation of a protrusion in the direction of migration, the elongation of the microtubules that fill the protrusion, and the reorientation of the centrosome, which serves as a microtubule-organizing center toward the direction of migration. This in vitro migration assay allows us to simultaneously investigate the mechanisms controlling Cell migration, Cell protrusion, and Cell polarization. Primary astrocytes, although more constraining, provide a more physiological model than immortalized Cell lines. Moreover, astrocyte culture can be obtained in a large number and, therefore, also allows biochemical analysis. Here I describe the procedure by which we can obtain and purify primary rat astrocytes and the different assays we have previously used to analyze the role of Rho GTPases and their downstream targets in Cell migration and polarization.
Benoit Ladoux - One of the best experts on this subject based on the ideXlab platform.
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emerging modes of collective Cell migration induced by geometrical constraints
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Sri Ram Krishna Vedula, Man Chun Leong, Tan Lei Lai, Pascal Hersen, Alexandre Kabla, Chwee Teck Lim, Benoit LadouxAbstract:The role of geometrical confinement on collective Cell migration has been recognized but has not been elucidated yet. Here, we show that the geometrical properties of the environment regulate the formation of collective Cell migration patterns through Cell–Cell interactions. Using microfabrication techniques to allow epithelial Cell sheets to migrate into strips whose width was varied from one up to several Cell diameters, we identified the modes of collective migration in response to geometrical constraints. We observed that a decrease in the width of the strips is accompanied by an overall increase in the speed of the Migrating Cell sheet. Moreover, large-scale vortices over tens of Cell lengths appeared in the wide strips whereas a contraction-elongation type of motion is observed in the narrow strips. Velocity fields and traction force signatures within the Cellular population revealed migration modes with alternative pulling and/or pushing mechanisms that depend on extrinsic constraints. Force transmission through interCellular contacts plays a key role in this process because the disruption of Cell–Cell junctions abolishes directed collective migration and passive Cell–Cell adhesions tend to move the Cells uniformly together independent of the geometry. Altogether, these findings not only demonstrate the existence of patterns of collective Cell migration depending on external constraints but also provide a mechanical explanation for how large-scale interactions through Cell–Cell junctions can feed back to regulate the organization of Migrating tissues.
Rhoda J Hawkins - One of the best experts on this subject based on the ideXlab platform.
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calculation of the force field required for nucleus deformation during Cell migration through constrictions
PLOS Computational Biology, 2021Co-Authors: Ian D Estabrook, Hawa Racine Thiam, Matthieu Piel, Rhoda J HawkinsAbstract:During Cell migration in confinement, the nucleus has to deform for a Cell to pass through small constrictions. Such nuclear deformations require significant forces. A direct experimental measure of the deformation force field is extremely challenging. However, experimental images of nuclear shape are relatively easy to obtain. Therefore, here we present a method to calculate predictions of the deformation force field based purely on analysis of experimental images of nuclei before and after deformation. Such an inverse calculation is technically non-trivial and relies on a mechanical model for the nucleus. Here we compare two simple continuum elastic models of a Cell nucleus undergoing deformation. In the first, we treat the nucleus as a homogeneous elastic solid and, in the second, as an elastic shell. For each of these models we calculate the force field required to produce the deformation given by experimental images of nuclei in dendritic Cells Migrating in microchannels with constrictions of controlled dimensions. These microfabricated channels provide a simplified confined environment mimicking that experienced by Cells in tissues. Our calculations predict the forces felt by a deforming nucleus as a Migrating Cell encounters a constriction. Since a direct experimental measure of the deformation force field is very challenging and has not yet been achieved, our numerical approaches can make important predictions motivating further experiments, even though all the parameters are not yet available. We demonstrate the power of our method by showing how it predicts lateral forces corresponding to actin polymerisation around the nucleus, providing evidence for actin generated forces squeezing the sides of the nucleus as it enters a constriction. In addition, the algorithm we have developed could be adapted to analyse experimental images of deformation in other situations.
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calculation of the force field required for nucleus deformation during Cell migration through constrictions
bioRxiv, 2020Co-Authors: Ian D Estabrook, Hawa Racine Thiam, Matthieu Piel, Rhoda J HawkinsAbstract:Abstract During Cell migration in confinement, the nucleus has to deform for a Cell to pass through small constrictions. Such nuclear deformations require significant forces. A direct experimental measure of the deformation force field is extremely challenging. However, experimental images of nuclear shape are relatively easy to obtain. Therefore, here we present a method to calculate predictions of the deformation force field based purely on analysis of experimental images of nuclei before and after deformation. Such an inverse calculation is technically non-trivial and relies on a mechanical model for the nucleus. Here we compare two simple continuum elastic models of a Cell nucleus undergoing deformation. In the first, we treat the nucleus as a homogeneous elastic solid and, in the second, as an elastic shell. For each of these models we calculate the force field required to produce the deformation given by experimental images of nuclei in dendritic Cells Migrating in microchannels with constrictions of controlled dimensions [1]. These microfabricated channels provide a simplified confined environment mimicking that experienced by Cells in tissues. We extract the nuclear shape from the boundary of the fluorescently stained region in each consecutive image over time. From this we calculate the deformation field between images and use our elastic models to calculate the traction force field. Our calculations therefore predict the forces felt by a deforming nucleus as a Migrating Cell encounters a constriction. Since a direct experimental measure of the deformation force field is very challenging and has not yet been achieved, our numerical approaches can make important predictions motivating further experiments, even though all the parameters are not yet available. In addition, the algorithm we have developed could be adapted to analyse experimental images of deformation in other situations. Author summary Many Cell types are able to migrate and squeeze through constrictions that are narrower than the Cell’s resting radius. For example, both immune Cells and metastatic cancer Cells change their shape to migrate through small holes in the complex tissue media they move in. During migration the Cell nucleus is more difficult to deform than the Cell cytoplasm and therefore significant forces are required for a Cell to pass through spaces that are smaller than the resting size of the nucleus. Experimental measurements of these forces are extremely challenging but experimental images of nuclear deformation are regularly obtained in many labs. Therefore we present a computational method to analyse experimental images of nuclear deformation to deduce the forces required to produce such deformations. A mechanical model of the nucleus is necessary for this analysis and here we present two different models. The first treats the nucleus as a homogeneous elastic solid and the second treats the nucleus as an elastic shell. Our computational tool enables us to obtain detailed information about forces causing deformation from microscopy images.
Jose N Onuchic - One of the best experts on this subject based on the ideXlab platform.
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a biophysical model uncovers the size distribution of Migrating Cell clusters across cancer types
Cancer Research, 2019Co-Authors: Federico Bocci, Mohit Kumar Jolly, Jose N OnuchicAbstract:Migration from the primary tumor is a crucial step in the metastatic cascade. Cells with various degrees of adhesion and motility migrate and are launched into the bloodstream as single circulating tumor Cells (CTC) or multiCellular CTC clusters. The frequency and size distributions of these clusters have been recently measured, but the underlying mechanisms enabling these different modes of migration remain poorly understood. We present a biophysical model that couples the phenotypic plasticity enabled by the epithelial-mesenchymal transition (EMT) and Cell migration to explain the modes of individual and collective cancer Cell migration. This reduced physical model captures how Cells undergo a transition from individual migration to collective Cell migration and robustly recapitulates CTC cluster fractions and size distributions observed experimentally across several cancer types, thus suggesting the existence of common features in the mechanisms underlying cancer Cell migration. Furthermore, we identify mechanisms that can maximize the fraction of CTC clusters in circulation. First, mechanisms that prevent a complete EMT and instead increase the population of hybrid epithelial/mesenchymal (E/M) Cells are required to recapitulate CTC size distributions with large clusters of 5 to 10 Cells. Second, multiple intermediate E/M states give rise to larger and heterogeneous clusters formed by Cells with different epithelial-mesenchymal traits. Overall, this biophysical model provides a platform to continue to bridge the gap between the molecular and biophysical regulation of cancer Cell migration and highlights that a complete EMT might not be required for metastasis. SIGNIFICANCE: A biophysical model of cancer Cell invasion integrates phenotypic heterogeneity and Cell migration to interpret experimental observations of circulating tumor Cell clusters and provides new predictions.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/21/5527/F1.large.jpg.
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a biophysical model uncovers the size distribution of Migrating Cell clusters across cancer types
bioRxiv, 2019Co-Authors: Federico Bocci, Mohit Kumar Jolly, Jose N OnuchicAbstract:Abstract The gain of Cellular motility via the epithelial-mesenchymal transition (EMT) is considered crucial in the metastatic cascade. Cells undergoing EMT to varying extents are launched into the bloodstream as single circulating tumor Cells (CTCs) or multi-Cellular clusters. The frequency and size distributions of these multi-Cellular clusters has been recently measured, but the underlying mechanisms enabling these different modes of migration remain poorly understood. We present a biophysical model that couples the epithelial-mesenchymal phenotypic transition and Cell migration to explain these different modes of cancer Cell migration. With this reduced physical model, we identify a transition from individual migration to clustered Cell migration that is regulated by the rate of EMT and the degree of cooperativity between Cells during migration. This single Cell to clustered migration transition can robustly recapitulate cluster size distributions observed experimentally across several cancer types, thus suggesting the existence of common features in the mechanisms of Cell migration during metastasis. Furthermore, we identify three main mechanisms that can facilitate the formation and dissemination of large clusters: first, mechanisms that prevent a complete EMT and instead increase the population of hybrid Epithelial/Mesenchymal (E/M) Cells; second, multiple intermediate E/M states that give rise to heterogeneous clusters formed by Cells with different epithelial-mesenchymal traits; and third, non-Cell-autonomous induction of EMT via Cell-to-Cell signaling that gives rise to spatial correlations among Cells in a tissue. Overall, this biophysical model represents a first step toward bridging the gap between the molecular and biophysical understanding of EMT and various modes of cancer Cell migration, and highlights that a complete EMT might not be required for metastasis. Statement of significance The Epithelial-Mesenchymal Transition (EMT) confers motility and invasive traits to cancer Cells. These Cells can then enter the circulatory system both as single Cells or as multi-Cellular clusters to initiate metastases. We develop a biophysical model to investigate how EMT at the single Cell level can give rise to a solitary or clustered Cell migration. This model quantitatively reproduces cluster size distributions reported in human circulation and mouse models, therefore suggesting similar mechanisms in cancer Cell migration across different cancer types. Moreover, we show that a partial EMT to a hybrid epithelial/mesenchymal Cell state is sufficient to explain both single Cell and clustered migration, therefore questioning the necessity of a complete EMT for cancer metastasis.
M A Teillet - One of the best experts on this subject based on the ideXlab platform.
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early and late Migrating cranial neural crest Cell populations have equivalent developmental potential in vivo
Development, 1997Co-Authors: Clare V H Baker, Marianne Bronnerfraser, N Le M Douarin, M A TeilletAbstract:We present the first in vivo study of the long-term fate and potential of early-Migrating and late-Migrating mesencephalic neural crest Cell populations, by performing isochronic and heterochronic quail-to-chick grafts. Both early- and late-Migrating populations form melanocytes, neurons, glia, cartilage and bone in isochronic, isotopic chimeras, showing that neither population is lineage-restricted. The early-Migrating population distributes both dorsally and ventrally during normal development, while the late-Migrating population is confined dorsally and forms much less cartilage and bone. When the late-Migrating population is substituted heterochronically for the early-Migrating population, it contributes extensively to ventral derivatives such as jaw cartilage and bone. Conversely, when the early-Migrating population is substituted heterochronically for the late-Migrating population, it no longer contributes to the jaw skeleton and only forms dorsal derivatives. When the late-Migrating population is grafted into a late-stage host whose neural crest had previously been ablated, it migrates ventrally into the jaws. Thus, the dorsal fate restriction of the late-Migrating mesencephalic neural crest Cell population in normal development is due to the presence of earlier-Migrating neural crest Cells, rather than to any change in the environment or to any intrinsic difference in migratory ability or potential between early- and late-Migrating Cell populations. These results highlight the plasticity of the neural crest and show that its fate is determined primarily by the environment.