N-cadherin and β1-integrins cooperate during the development of the enteric nervous system

AbstractCell adhesion controls various embryonic morphogenetic processes, including the development of the enteric nervous system (ENS). Ablation of β1-integrin (β1−/−) expression in enteric neural crest cells (ENCC) in mice leads to major alterations in the ENS structure caused by reduced migration and increased aggregation properties of ENCC during gut colonization, which gives rise to a Hirschsprung's disease-like phenotype.In the present study, we examined the role of N-cadherin in ENS development and the interplay with β1 integrins during this process. The Ht–PA–Cre mouse model was used to target gene disruption of N-cadherin and β1 integrin in migratory NCC and to produce single- and double-conditional mutants for these two types of adhesion receptors.Double mutation of N-cadherin and β1 integrin led to embryonic lethality with severe defects in ENS development. N-cadherin-null (Ncad−/−) ENCC exhibited a delayed colonization in the developing gut at E12.5, although this was to a lesser extent than in β1−/− mutants. This delay of Ncad−/− ENCC migration was recovered at later stages of development. The double Ncad−/−; β1−/− mutant ENCC failed to colonize the distal part of the gut and there was more severe aganglionosis in the proximal hindgut than in the single mutants for N-cadherin or β1-integrin. This was due to an altered speed of locomotion and directionality in the gut wall. The abnormal aggregation defect of ENCC and the disorganized ganglia network in the β1−/− mutant was not observed in the double mutant. This indicates that N-cadherin enhances the effect of the β1−integrin mutation and demonstrates cooperation between these two adhesion receptors during ENS ontogenesis.In conclusion, our data reveal that N-cadherin is not essential for ENS development but it does modulate the modes of ENCC migration and acts in concert with β1−integrin to control the proper development of the ENS

Correlated Multimodal Imaging in Life Sciences:Expanding the Biomedical Horizon

International audienceThe frontiers of bioimaging are currently being pushed toward the integration and correlation of several modalities to tackle biomedical research questions holistically and across multiple scales. Correlated Multimodal Imaging (CMI) gathers information about exactly the same specimen with two or more complementary modalities that-in combination-create a composite and complementary view of the sample (including insights into structure, function, dynamics and molecular composition). CMI allows to describe biomedical processes within their overall spatio-temporal context and gain a mechanistic understanding of cells, tissues, diseases or organisms by untangling their molecular mechanisms within their native environment. The two best-established CMI implementations for small animals and model organisms are hardware-fused platforms in preclinical imaging (Hybrid Imaging) and Correlated Light and Electron Microscopy (CLEM) in biological imaging. Although the merits of Preclinical Hybrid Imaging (PHI) and CLEM are well-established, both approaches would benefit from standardization of protocols, ontologies and data handling, and the development of optimized and advanced implementations. Specifically, CMI pipelines that aim at bridging preclinical and biological imaging beyond CLEM and PHI are rare but bear great potential to substantially advance both bioimaging and biomedical research. CMI faces three mai

LINC complex-Lisl interplay controls MT1-MMP matrix digest-on-demand response for confined tumor cell migration

Cancer cells' ability to migrate through constricting pores in the tissue matrix is limited by nuclear stiffness. MT1-MMP contributes to metastasis by widening matrix pores, facilitating confined migration. Here, we show that modulation of matrix pore size or of lamin A expression known to modulate nuclear stiffness directly impinges on levels of MT1-MMP-mediated pericellular collagenolysis by cancer cells. A component of this adaptive response is the centrosome-centered distribution of MT1-MMP intracellular storage compartments ahead of the nucleus. We further show that this response, including invadopodia formation in association with confining matrix fibrils, requires an intact connection between the nucleus and the centrosome via the linker of nucleoskeleton and cytoskeleton (LINC) complex protein nesprin-2 and dynein adaptor Lis1. Our results uncover a digest-on-demand strategy for nuclear translocation through constricted spaces whereby confined migration triggers polarization of MT1-MMP storage compartments and matrix proteolysis in front of the nucleus depending on nucleus-microtubule linkage

The CryoCapsule : Simplifying Correlative Light to Electron Microscopy

Correlating complementary multiple scale images of the same object is a straightforward means to decipher biological processes. Light microscopy and electron microscopy are the most commonly used imaging techniques, yet despite their complementarity, the experimental procedures available to correlate them are technically complex. We designed and manufactured a new device adapted to many biological specimens, the CryoCapsule, that simplifies the multiple sample preparation steps, which at present separate live cell fluorescence imaging from contextual high-resolution electron microscopy, thus opening new strategies for full correlative light to electron microscopy. We tested the biological application of this highly optimized tool on three different specimens: the in vitro Xenopus laevis mitotic spindle, melanoma cells over-expressing YFP-langerin sequestered in organized membranous subcellular organelles and a pigmented melanocytic cell in which the endosomal system was labeled with internalized fluorescent transferrin

EDAM-bioimaging : The ontology of bioimage informatics operations, topics, data, and formats

International audienceThe ontology of bioimage informatics operations, topics, data, and formats What? EDAM-bioimaging is an extension of the EDAM ontology, dedicated to bioimage analysis, bioimage informatics, and bioimaging. Why? EDAM-bioimaging enables interoperable descriptions of software, publications, data, and workflows, fostering reliable and transparent science. How? EDAM-bioimaging is developed in a community spirit, in a welcoming collaboration between numerous bioimaging experts and ontology developers. How can I contribute? We need your expertise! You can help by reviewing parts of EDAM-bioimaging, posting comments with suggestions, requirements, or needs for clarification, or participating in a Taggathon or another hackathon. Please see https://github.com/edamontology/edam-bioimaging#contributing. EDAM-bioimaging is developed in an interdisciplinary open collaboration supported by the hosting institutions, participating individuals, and NEUBIAS COST Action (CA15124) and ELIXIR-EXCELERATE (676559) funded by the Horizon 2020 Framework Programme of the European Union. https://github.com/edamontology/edam-bioimaging @edamontology /edamontology/edam-bioimagin

The first World Cell Race

Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers 5, 6. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin

3D Correlative Cryo-Structured Illumination Fluorescence and Soft X-ray Microscopy Elucidates Reovirus Intracellular Release Pathway

Imaging of biological matter across resolution scales entails the challenge of preserving the direct and unambiguous correlation of subject features from the macroscopic to the microscopic level. Here, we present a correlative imaging platform developed specifically for imaging cells in 3D under cryogenic conditions by using X-rays and visible light. Rapid cryo-preservation of biological specimens is the current gold standard in sample preparation for ultrastructural analysis in X-ray imaging. However, cryogenic fluorescence localization methods are, in their majority, diffraction-limited and fail to deliver matching resolution. We addressed this technological gap by developing an integrated, user-friendly platform for 3D correlative imaging of cells in vitreous ice by using super-resolution structured illumination microscopy in conjunction with soft X-ray tomography. The power of this approach is demonstrated by studying the process of reovirus release from intracellular vesicles during the early stages of infection and identifying intracellular virus-induced structures

Preparation of novel optical fibre-based Cocaine sensors using a molecular imprinted polymer approach

Novel chemical sensors using fibre optic-based techniques for the detection of Cocaine have been developed, utilising molecularly imprinted polymers (MIPs) containing fluorescein moieties as the signalling groups. The fluorescent MIPs were formed and covalently attached to the distal end of specially chosen optical fibres to create fibre optic probe-based sensors. These sensors exhibited are producible and quantifiable change in the intensity of the fluorescence signal received from the sensor in response to Cocaine in aqueous acetonitrile mixtures. High selectivity for Cocaine over Codeine and a range of known Cocaine interferants has been demonstrated for one of the sensors developed in this work