1
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Toullec G, Rädecker N, Pogoreutz C, Banc-Prandi G, Escrig S, Genoud C, Olmos CM, Spangenberg J, Meibom A. Host starvation and in hospite degradation of algal symbionts shape the heat stress response of the Cassiopea-Symbiodiniaceae symbiosis. Microbiome 2024; 12:42. [PMID: 38424629 PMCID: PMC10902967 DOI: 10.1186/s40168-023-01738-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 12/11/2023] [Indexed: 03/02/2024]
Abstract
BACKGROUND Global warming is causing large-scale disruption of cnidarian-Symbiodiniaceae symbioses fundamental to major marine ecosystems, such as coral reefs. However, the mechanisms by which heat stress perturbs these symbiotic partnerships remain poorly understood. In this context, the upside-down jellyfish Cassiopea has emerged as a powerful experimental model system. RESULTS We combined a controlled heat stress experiment with isotope labeling and correlative SEM-NanoSIMS imaging to show that host starvation is a central component in the chain of events that ultimately leads to the collapse of the Cassiopea holobiont. Heat stress caused an increase in catabolic activity and a depletion of carbon reserves in the unfed host, concurrent with a reduction in the supply of photosynthates from its algal symbionts. This state of host starvation was accompanied by pronounced in hospite degradation of algal symbionts, which may be a distinct feature of the heat stress response of Cassiopea. Interestingly, this loss of symbionts by degradation was concealed by body shrinkage of the starving animals, resulting in what could be referred to as "invisible" bleaching. CONCLUSIONS Overall, our study highlights the importance of the nutritional status in the heat stress response of the Cassiopea holobiont. Compared with other symbiotic cnidarians, the large mesoglea of Cassiopea, with its structural sugar and protein content, may constitute an energy reservoir capable of delaying starvation. It seems plausible that this anatomical feature at least partly contributes to the relatively high stress tolerance of these animals in rapidly warming oceans. Video Abstract.
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Affiliation(s)
- Gaëlle Toullec
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland.
| | - Nils Rädecker
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Claudia Pogoreutz
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
- PSL Université Paris: EPHE-UPVD-CNRS, UAR 3278 CRIOBE, Université de Perpignan, 52 Avenue Paul Alduy, Perpignan Cedex, 66860, France
| | - Guilhem Banc-Prandi
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, University of Lausanne, Lausanne, 1015, Switzerland
| | - Cristina Martin Olmos
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Science, University of Lausanne, Lausanne, 1015, Switzerland
| | - Jorge Spangenberg
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, 1015, Switzerland
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland.
- Center for Advanced Surface Analysis, Institute of Earth Science, University of Lausanne, Lausanne, 1015, Switzerland.
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2
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Quinn A, El Chazli Y, Escrig S, Daraspe J, Neuschwander N, McNally A, Genoud C, Meibom A, Engel P. Host-derived organic acids enable gut colonization of the honey bee symbiont Snodgrassella alvi. Nat Microbiol 2024; 9:477-489. [PMID: 38225461 DOI: 10.1038/s41564-023-01572-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 11/30/2023] [Indexed: 01/17/2024]
Abstract
Diverse bacteria can colonize the animal gut using dietary nutrients or by engaging in microbial crossfeeding interactions. Less is known about the role of host-derived nutrients in enabling gut bacterial colonization. Here we examined metabolic interactions within the evolutionary ancient symbiosis between the honey bee (Apis mellifera) and the core gut microbiota member Snodgrassella alvi. This betaproteobacterium is incapable of metabolizing saccharides, yet colonizes the honey bee gut in the presence of a sugar-only diet. Using comparative metabolomics, 13C-tracers and nanoscale secondary ion mass spectrometry (NanoSIMS), we show in vivo that S. alvi grows on host-derived organic acids, including citrate, glycerate and 3-hydroxy-3-methylglutarate, which are actively secreted by the host into the gut lumen. S. alvi also modulates tryptophan metabolism in the gut by converting kynurenine to anthranilate. These results suggest that S. alvi is adapted to a specific metabolic niche in the honey bee gut that depends on host-derived nutritional resources.
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Affiliation(s)
- Andrew Quinn
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Yassine El Chazli
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jean Daraspe
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Neuschwander
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Aoife McNally
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Anders Meibom
- Laboratory for Biological Geochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
| | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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Olive M, Daraspe J, Genoud C, Kohn T. Uptake without inactivation of human adenovirus type 2 by Tetrahymena pyriformis ciliates. Environ Sci Process Impacts 2023. [PMID: 37376996 DOI: 10.1039/d3em00116d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Human adenoviruses are ubiquitous contaminants of surface water. Indigenous protists may interact with adenoviruses and contribute to their removal from the water column, though the associated kinetics and mechanisms differ between protist species. In this work, we investigated the interaction of human adenovirus type 2 (HAdV2) with the ciliate Tetrahymena pyriformis. In co-incubation experiments in a freshwater matrix, T. pyriformis was found to efficiently remove HAdV2 from the aqueous phase, with ≥4 log10 removal over 72 hours. Neither sorption onto the ciliate nor secreted compounds contributed to the observed loss of infectious HAdV2. Instead, internalization was shown to be the dominant removal mechanism, resulting in the presence of viral particles inside food vacuoles of T. pyriformis, as visualized by transmission electron microscopy. The fate of HAdV2 once ingested was scrutinized and no evidence of virus digestion was found over the course of 48 hours. This work shows that T. pyriformis can exert a dual role in microbial water quality: while they remove infectious adenovirus from the water column, they can also accumulate infectious viruses.
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Affiliation(s)
- Margot Olive
- Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Jean Daraspe
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne (UNIL), Lausanne, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne (UNIL), Lausanne, Switzerland
| | - Tamar Kohn
- Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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4
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Meibom A, Plane F, Cheng T, Grandjean G, Haldimann O, Escrig S, Jensen L, Daraspe J, Mucciolo A, De Bellis D, Rädecker N, Martin-Olmos C, Genoud C, Comment A. Correlated cryo-SEM and CryoNanoSIMS imaging of biological tissue. BMC Biol 2023; 21:126. [PMID: 37280616 DOI: 10.1186/s12915-023-01623-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 05/10/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND The development of nanoscale secondary ion mass spectrometry (NanoSIMS) has revolutionized the study of biological tissues by enabling, e.g., the visualization and quantification of metabolic processes at subcellular length scales. However, the associated sample preparation methods all result in some degree of tissue morphology distortion and loss of soluble compounds. To overcome these limitations an entirely cryogenic sample preparation and imaging workflow is required. RESULTS Here, we report the development of a CryoNanoSIMS instrument that can perform isotope imaging of both positive and negative secondary ions from flat block-face surfaces of vitrified biological tissues with a mass- and image resolution comparable to that of a conventional NanoSIMS. This capability is illustrated with nitrogen isotope as well as trace element mapping of freshwater hydrozoan Green Hydra tissue following uptake of 15N-enriched ammonium. CONCLUSION With a cryo-workflow that includes vitrification by high pressure freezing, cryo-planing of the sample surface, and cryo-SEM imaging, the CryoNanoSIMS enables correlative ultrastructure and isotopic or elemental imaging of biological tissues in their most pristine post-mortem state. This opens new horizons in the study of fundamental processes at the tissue- and (sub)cellular level. TEASER CryoNanoSIMS: subcellular mapping of chemical and isotopic compositions of biological tissues in their most pristine post-mortem state.
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Affiliation(s)
- Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland.
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland.
| | - Florent Plane
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Tian Cheng
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Gilles Grandjean
- Mechanical Workshop, School of Basic Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - Olivier Haldimann
- Mechanical Workshop, School of Basic Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - Stephane Escrig
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Louise Jensen
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Jean Daraspe
- Electron Microscopy Facility, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Antonio Mucciolo
- Electron Microscopy Facility, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Damien De Bellis
- Electron Microscopy Facility, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Nils Rädecker
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Cristina Martin-Olmos
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Arnaud Comment
- Institute of Physics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
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5
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Jiao W, Chatton JY, Genoud C. Mitochondria morphometry in 3D datasets obtained from mouse brains with serial block-face scanning electron microscopy. Methods Cell Biol 2023; 177:197-211. [PMID: 37451767 DOI: 10.1016/bs.mcb.2023.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
The dysfunction of mitochondria is linked with many diseases. In the nervous system, evidence of their implication in neurodegenerative disease is growing. Mitochondria health is assessed by their impact on cellular metabolism but alterations in their morphologies and locations in the cells can also be markers of dysfunctions. Light microscopy techniques allow us to look at mitochondria in vivo in cells or tissue. But in the case of the nervous system, in order to assess the precise location of mitochondria in different cell types and neuronal compartments (cell bodies, dendrites or axons), electron microscopy is required. While the percentage of volume occupied by mitochondria can be assessed on 2D images, alterations in length, branching, and interactions with other organelles require three-dimensional (3D) segmentation of mitochondria in volumes imaged at ultrastructural level. Nowadays three-dimensional volume electron microscopy (vEM) imaging techniques such as serial block face scanning electron microscopy (SBF-SEM) enable us to image 3D volumes of tissue at ultrastructural level and can be done routinely. Segmentation of all the neuropil is also successfully achieved at a large scale in the nervous system. Here, we show a workflow based on open access resources, which allows us to image, segment, and analyze mitochondria in 3D volumes of regions of interest in the mouse brain. Taking advantage of recent developments, e.g., pre-trained models for mitochondria, we speed up the reconstruction and analysis. We also critically assess the impact on the results of the different reconstruction methods chosen and the level of manual corrections invested.
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Affiliation(s)
- Wei Jiao
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Jean-Yves Chatton
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
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6
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Saponara E, Penno C, Orsini V, Wang ZY, Fischer A, Aebi A, Matadamas-Guzman ML, Brun V, Fischer B, Brousseau M, O'Donnell P, Turner J, Graff Meyer A, Bollepalli L, d'Ario G, Roma G, Carbone W, Annunziato S, Obrecht M, Beckmann N, Saravanan C, Osmont A, Tropberger P, Richards SM, Genoud C, Ley S, Ksiazek I, Nigsch F, Terracciano LM, Schadt HS, Bouwmeester T, Tchorz JS, Ruffner H. Loss of Hepatic Leucine-Rich Repeat-Containing G-Protein Coupled Receptors 4 and 5 Promotes Nonalcoholic Fatty Liver Disease. Am J Pathol 2023; 193:161-181. [PMID: 36410420 DOI: 10.1016/j.ajpath.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 10/06/2022] [Accepted: 10/19/2022] [Indexed: 11/19/2022]
Abstract
The roof plate-specific spondin-leucine-rich repeat-containing G-protein coupled receptor 4/5 (LGR4/5)-zinc and ring finger 3 (ZNRF3)/ring finger protein 43 (RNF43) module is a master regulator of hepatic Wnt/β-catenin signaling and metabolic zonation. However, its impact on nonalcoholic fatty liver disease (NAFLD) remains unclear. The current study investigated whether hepatic epithelial cell-specific loss of the Wnt/β-catenin modulator Lgr4/5 promoted NAFLD. The 3- and 6-month-old mice with hepatic epithelial cell-specific deletion of both receptors Lgr4/5 (Lgr4/5dLKO) were compared with control mice fed with normal diet (ND) or high-fat diet (HFD). Six-month-old HFD-fed Lgr4/5dLKO mice developed hepatic steatosis and fibrosis but the control mice did not. Serum cholesterol-high-density lipoprotein and total cholesterol levels in 3- and 6-month-old HFD-fed Lgr4/5dLKO mice were decreased compared with those in control mice. An ex vivo primary hepatocyte culture assay and a comprehensive bile acid (BA) characterization in liver, plasma, bile, and feces demonstrated that ND-fed Lgr4/5dLKO mice had impaired BA secretion, predisposing them to develop cholestatic characteristics. Lipidome and RNA-sequencing analyses demonstrated severe alterations in several lipid species and pathways controlling lipid metabolism in the livers of Lgr4/5dLKO mice. In conclusion, loss of hepatic Wnt/β-catenin activity by Lgr4/5 deletion led to loss of BA secretion, cholestatic features, altered lipid homeostasis, and deregulation of lipoprotein pathways. Both BA and intrinsic lipid alterations contributed to the onset of NAFLD.
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Affiliation(s)
- Enrica Saponara
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Carlos Penno
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Vanessa Orsini
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Zhong-Yi Wang
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Audrey Fischer
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Alexandra Aebi
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Meztli L Matadamas-Guzman
- Instituto Nacional de Medicina Genómica-Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Virginie Brun
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Benoit Fischer
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Margaret Brousseau
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Peter O'Donnell
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Jonathan Turner
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Alexandra Graff Meyer
- Friedrich Miescher Institute for BioMedical Research, Facility for Advanced Imaging and Microscopy, Basel, Switzerland
| | - Laura Bollepalli
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Giovanni d'Ario
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Walter Carbone
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Stefano Annunziato
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Michael Obrecht
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Nicolau Beckmann
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Chandra Saravanan
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Arnaud Osmont
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Philipp Tropberger
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Shola M Richards
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Svenja Ley
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Iwona Ksiazek
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Florian Nigsch
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Luigi M Terracciano
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Humanitas Research Hospital, Anatomia Patologica, Rozzano, Milan, Italy
| | - Heiko S Schadt
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Tewis Bouwmeester
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Jan S Tchorz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Heinz Ruffner
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland.
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7
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Saponara E, Penno C, Orsini V, Wang ZY, Fischer A, Aebi A, Matadamas-Guzman ML, Brun V, Fischer B, Brousseau M, O'Donnell P, Turner J, Graff Meyer A, Bollepalli L, d'Ario G, Roma G, Carbone W, Annunziato S, Obrecht M, Beckmann N, Saravanan C, Osmont A, Tropberger P, Richards SM, Genoud C, Ley S, Ksiazek I, Nigsch F, Terracciano LM, Schadt HS, Bouwmeester T, Tchorz JS, Ruffner H. Loss of Hepatic Leucine-Rich Repeat-Containing G-Protein Coupled Receptors 4 and 5 Promotes Nonalcoholic Fatty Liver Disease. Am J Pathol 2023. [PMID: 36410420 DOI: 10.1016/j.ajpath.2022.10.00] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The roof plate-specific spondin-leucine-rich repeat-containing G-protein coupled receptor 4/5 (LGR4/5)-zinc and ring finger 3 (ZNRF3)/ring finger protein 43 (RNF43) module is a master regulator of hepatic Wnt/β-catenin signaling and metabolic zonation. However, its impact on nonalcoholic fatty liver disease (NAFLD) remains unclear. The current study investigated whether hepatic epithelial cell-specific loss of the Wnt/β-catenin modulator Lgr4/5 promoted NAFLD. The 3- and 6-month-old mice with hepatic epithelial cell-specific deletion of both receptors Lgr4/5 (Lgr4/5dLKO) were compared with control mice fed with normal diet (ND) or high-fat diet (HFD). Six-month-old HFD-fed Lgr4/5dLKO mice developed hepatic steatosis and fibrosis but the control mice did not. Serum cholesterol-high-density lipoprotein and total cholesterol levels in 3- and 6-month-old HFD-fed Lgr4/5dLKO mice were decreased compared with those in control mice. An ex vivo primary hepatocyte culture assay and a comprehensive bile acid (BA) characterization in liver, plasma, bile, and feces demonstrated that ND-fed Lgr4/5dLKO mice had impaired BA secretion, predisposing them to develop cholestatic characteristics. Lipidome and RNA-sequencing analyses demonstrated severe alterations in several lipid species and pathways controlling lipid metabolism in the livers of Lgr4/5dLKO mice. In conclusion, loss of hepatic Wnt/β-catenin activity by Lgr4/5 deletion led to loss of BA secretion, cholestatic features, altered lipid homeostasis, and deregulation of lipoprotein pathways. Both BA and intrinsic lipid alterations contributed to the onset of NAFLD.
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Affiliation(s)
- Enrica Saponara
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Carlos Penno
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Vanessa Orsini
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Zhong-Yi Wang
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Audrey Fischer
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Alexandra Aebi
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Meztli L Matadamas-Guzman
- Instituto Nacional de Medicina Genómica-Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Virginie Brun
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Benoit Fischer
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Margaret Brousseau
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Peter O'Donnell
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Jonathan Turner
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Alexandra Graff Meyer
- Friedrich Miescher Institute for BioMedical Research, Facility for Advanced Imaging and Microscopy, Basel, Switzerland
| | - Laura Bollepalli
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Giovanni d'Ario
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Walter Carbone
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Stefano Annunziato
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Michael Obrecht
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Nicolau Beckmann
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Chandra Saravanan
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, Massachusetts
| | - Arnaud Osmont
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Philipp Tropberger
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Shola M Richards
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Christel Genoud
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Svenja Ley
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Iwona Ksiazek
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Florian Nigsch
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Luigi M Terracciano
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Humanitas Research Hospital, Anatomia Patologica, Rozzano, Milan, Italy
| | - Heiko S Schadt
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Tewis Bouwmeester
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Jan S Tchorz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Heinz Ruffner
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland.
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8
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Ballmer D, Tardat M, Ortiz R, Graff-Meyer A, Ozonov E, Genoud C, Peters A, Fanourgakis G. HP1 proteins regulate nucleolar structure and function by secluding pericentromeric constitutive heterochromatin. Nucleic Acids Res 2022; 51:117-143. [PMID: 36533441 PMCID: PMC9841413 DOI: 10.1093/nar/gkac1159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/29/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Nucleoli are nuclear compartments regulating ribosome biogenesis and cell growth. In embryonic stem cells (ESCs), nucleoli containing transcriptionally active ribosomal genes are spatially separated from pericentromeric satellite repeat sequences packaged in largely repressed constitutive heterochromatin (PCH). To date, mechanisms underlying such nuclear partitioning and the physiological relevance thereof are unknown. Here we show that repressive chromatin at PCH ensures structural integrity and function of nucleoli during cell cycle progression. Loss of heterochromatin proteins HP1α and HP1β causes deformation of PCH, with reduced H3K9 trimethylation (H3K9me3) and HP1γ levels, absence of H4K20me3 and upregulated major satellites expression. Spatially, derepressed PCH aberrantly associates with nucleoli accumulating severe morphological defects during S/G2 cell cycle progression. Hp1α/β deficiency reduces cell proliferation, ribosomal RNA biosynthesis and mobility of Nucleophosmin, a major nucleolar component. Nucleolar integrity and function require HP1α/β proteins to be recruited to H3K9me3-marked PCH and their ability to dimerize. Correspondingly, ESCs deficient for both Suv39h1/2 H3K9 HMTs display similar nucleolar defects. In contrast, Suv4-20h1/2 mutant ESCs lacking H4K20me3 at PCH do not. Suv39h1/2 and Hp1α/β deficiency-induced nucleolar defects are reminiscent of those defining human ribosomopathy disorders. Our results reveal a novel role for SUV39H/HP1-marked repressive constitutive heterochromatin in regulating integrity, function and physiology of nucleoli.
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Affiliation(s)
- Daniel Ballmer
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland,Faculty of Sciences, University of Basel, 4056 Basel, Switzerland
| | - Mathieu Tardat
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Raphael Ortiz
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Alexandra Graff-Meyer
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Evgeniy A Ozonov
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | | | - Grigorios Fanourgakis
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
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9
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Peddie CJ, Genoud C, Kreshuk A, Meechan K, Micheva KD, Narayan K, Pape C, Parton RG, Schieber NL, Schwab Y, Titze B, Verkade P, Aubrey A, Collinson LM. Volume electron microscopy. Nat Rev Methods Primers 2022; 2:51. [PMID: 37409324 PMCID: PMC7614724 DOI: 10.1038/s43586-022-00131-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/10/2022] [Indexed: 07/07/2023]
Abstract
Life exists in three dimensions, but until the turn of the century most electron microscopy methods provided only 2D image data. Recently, electron microscopy techniques capable of delving deep into the structure of cells and tissues have emerged, collectively called volume electron microscopy (vEM). Developments in vEM have been dubbed a quiet revolution as the field evolved from established transmission and scanning electron microscopy techniques, so early publications largely focused on the bioscience applications rather than the underlying technological breakthroughs. However, with an explosion in the uptake of vEM across the biosciences and fast-paced advances in volume, resolution, throughput and ease of use, it is timely to introduce the field to new audiences. In this Primer, we introduce the different vEM imaging modalities, the specialized sample processing and image analysis pipelines that accompany each modality and the types of information revealed in the data. We showcase key applications in the biosciences where vEM has helped make breakthrough discoveries and consider limitations and future directions. We aim to show new users how vEM can support discovery science in their own research fields and inspire broader uptake of the technology, finally allowing its full adoption into mainstream biological imaging.
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Affiliation(s)
- Christopher J. Peddie
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, UK
| | - Christel Genoud
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Anna Kreshuk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Kimberly Meechan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Present address: Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Kristina D. Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Constantin Pape
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Robert G. Parton
- The Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicole L. Schieber
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Yannick Schwab
- Cell Biology and Biophysics Unit/ Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol, UK
| | - Aubrey Aubrey
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Lucy M. Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, UK
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10
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Wai CH, Jin J, Cyrklaff M, Genoud C, Funaya C, Sattler J, Maceski A, Meier S, Heiland S, Lanzer M, Frischknecht F, Kuhle J, Bendszus M, Hoffmann A. Neurofilament light chain plasma levels are associated with area of brain damage in experimental cerebral malaria. Sci Rep 2022; 12:10726. [PMID: 35750882 PMCID: PMC9232608 DOI: 10.1038/s41598-022-14291-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/03/2022] [Indexed: 11/23/2022] Open
Abstract
Neurofilament light chain (NfL), released during central nervous injury, has evolved as a powerful serum marker of disease severity in many neurological disorders, including infectious diseases. So far NfL has not been assessed in cerebral malaria in human or its rodent model experimental cerebral malaria (ECM), a disease that can lead to fatal brain edema or reversible brain edema. In this study we assessed if NfL serum levels can also grade disease severity in an ECM mouse model with reversible (n = 11) and irreversible edema (n = 10). Blood–brain-barrier disruption and brain volume were determined by magnetic resonance imaging. Neurofilament density volume as well as structural integrity were examined by electron microscopy in regions of most severe brain damage (olfactory bulb (OB), cortex and brainstem). NfL plasma levels in mice with irreversible edema (317.0 ± 45.01 pg/ml) or reversible edema (528.3 ± 125.4 pg/ml) were significantly increased compared to controls (103.4 ± 25.78 pg/ml) by three to five fold, but did not differ significantly in mice with reversible or irreversible edema. In both reversible and irreversible edema, the brain region most affected was the OB with highest level of blood–brain-barrier disruption and most pronounced decrease in neurofilament density volume, which correlated with NfL plasma levels (r = − 0.68, p = 0.045). In cortical and brainstem regions neurofilament density was only decreased in mice with irreversible edema and strongest in the brainstem. In reversible edema NfL plasma levels, MRI findings and neurofilament volume density normalized at 3 months’ follow-up. In conclusion, NfL plasma levels are elevated during ECM confirming brain damage. However, NfL plasma levels fail short on reliably indicating on the final outcomes in the acute disease stage that could be either fatal or reversible. Increased levels of plasma NfL during the acute disease stage are thus likely driven by the anatomical location of brain damage, the olfactory bulb, a region that serves as cerebral draining pathway into the nasal lymphatics.
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Affiliation(s)
- Chi Ho Wai
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.,Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Jessica Jin
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.,Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Marek Cyrklaff
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Christel Genoud
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Charlotta Funaya
- Electron Microscopy Core Facility, Heidelberg University, Heidelberg, Germany
| | - Julia Sattler
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Aleksandra Maceski
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel, University of Basel, Basel, Switzerland
| | - Stephanie Meier
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sabine Heiland
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Lanzer
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Friedrich Frischknecht
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany.,German Center for Infection Research (DZIF), Heidelberg, Germany
| | - Jens Kuhle
- Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel, University of Basel, Basel, Switzerland
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Angelika Hoffmann
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany. .,Department of Neuroradiology, University Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern, Inselspital, University of Bern, Freiburgstrasse, 3010, Bern, Switzerland.
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11
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Schenk AD, Cavadini S, Thomä NH, Genoud C. Live Analysis and Reconstruction of Single-Particle Cryo-Electron Microscopy Data with CryoFLARE. J Chem Inf Model 2020; 60:2561-2569. [PMID: 32233514 DOI: 10.1021/acs.jcim.9b01102] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Efficient, reproducible and accountable single-particle cryo-electron microscopy structure determination is tedious and often impeded by the lack of a standardized procedure for data analysis and processing. To address this issue, we have developed the FMI Live Analysis and Reconstruction Engine (CryoFLARE). CryoFLARE is a modular open-source platform offering easy integration of new processing algorithms developed by the cryo-EM community. It provides a user-friendly interface that allows fast setup of standardized workflows, serving the need of pharmaceutical industry and academia alike who need to optimize throughput of their microscope. To consistently document how data is processed, CryoFLARE contains an integrated reporting facility to create reports. Live analysis and processing parallel to data acquisition are used to monitor and optimize data quality. Problems at the level of the sample preparation (heterogeneity, ice thickness, sparse particles, areas selected for acquisition, etc.) or misalignments of the microscope optics can quickly be detected and rectified before data collection is continued. Interfacing with automated data collection software for retrieval of acquisition metadata reduces user input needed for analysis, and with it minimizes potential sources of errors and workflow inconsistencies. Local and remote export support in Relion-compatible job and data format allows seamless integration into the refinement process. The support for nonlinear workflows and fine-grained scheduling for mixed workflows with separate CPU and GPU based calculation steps ensures optimal use of processing hardware. CryoFLARE's flexibility allows it to be used for all types of image acquisitions, ranging from sample screening to high-resolution data collection, and it offers a new alternative for setting up image processing workflows. It can be used without modifications of the hardware/software delivered by the microscope supplier. As it runs on a server in parallel to the hardware used for acquisition, it can easily be set up for remote display connections and fast control of the acquisition status.
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Affiliation(s)
- Andreas D Schenk
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Simone Cavadini
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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12
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Corso G, Heusermann W, Trojer D, Görgens A, Steib E, Voshol J, Graff A, Genoud C, Lee Y, Hean J, Nordin JZ, Wiklander OPB, El Andaloussi S, Meisner-Kober N. Systematic characterization of extracellular vesicle sorting domains and quantification at the single molecule - single vesicle level by fluorescence correlation spectroscopy and single particle imaging. J Extracell Vesicles 2019; 8:1663043. [PMID: 31579435 PMCID: PMC6758720 DOI: 10.1080/20013078.2019.1663043] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 02/07/2023] Open
Abstract
Extracellular vesicles (EV) convey biological information by transmitting macromolecules between cells and tissues and are of great promise as pharmaceutical nanocarriers, and as therapeutic per se. Strategies for customizing the EV surface and cargo are being developed to enable their tracking, visualization, loading with pharmaceutical agents and decoration of the surface with tissue targeting ligands. While much progress has been made in the engineering of EVs, an exhaustive comparative analysis of the most commonly exploited EV-associated proteins, as well as a quantification at the molecular level are lacking. Here, we selected 12 EV-related proteins based on MS-proteomics data for comparative quantification of their EV engineering potential. All proteins were expressed with fluorescent protein (FP) tags in EV-producing cells; both parent cells as well as the recovered vesicles were characterized biochemically and biophysically. Using Fluorescence Correlation Spectroscopy (FCS) we quantified the number of FP-tagged molecules per vesicle. We observed different loading efficiencies and specificities for the different proteins into EVs. For the candidates showing the highest loading efficiency in terms of engineering, the molecular levels in the vesicles did not exceed ca 40-60 fluorescent proteins per vesicle upon transient overexpression in the cells. Some of the GFP-tagged EV reporters showed quenched fluorescence and were either non-vesicular, despite co-purification with EVs, or comprised a significant fraction of truncated GFP. The co-expression of each target protein with CD63 was further quantified by widefield and confocal imaging of single vesicles after double transfection of parent cells. In summary, we provide a quantitative comparison for the most commonly used sorting proteins for bioengineering of EVs and introduce a set of biophysical techniques for straightforward quantitative and qualitative characterization of fluorescent EVs to link single vesicle analysis with single molecule quantification.
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Affiliation(s)
- Giulia Corso
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Wolf Heusermann
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Imaging Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Dominic Trojer
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - André Görgens
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.,Institute for Transfusion Medicine, University Hospital Essen, Essen, Germany
| | - Emmanuelle Steib
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Department of Cell Biology, Sciences III, University of Geneva, Geneva Switzerland
| | - Johannes Voshol
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Alexandra Graff
- Facility for advanced imaging and microscopy, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Christel Genoud
- Facility for advanced imaging and microscopy, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Yi Lee
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Cancer and Stratified Oncology 5, Astar Genome Institute of Singapore, Singapore
| | - Justin Hean
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Joel Z Nordin
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Nicole Meisner-Kober
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Department of Biosciences, University of Salzburg, Salzburg, Austria
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13
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Shahmoradian SH, Lewis AJ, Genoud C, Hench J, Moors TE, Navarro PP, Castaño-Díez D, Schweighauser G, Graff-Meyer A, Goldie KN, Sütterlin R, Huisman E, Ingrassia A, Gier YD, Rozemuller AJM, Wang J, Paepe AD, Erny J, Staempfli A, Hoernschemeyer J, Großerüschkamp F, Niedieker D, El-Mashtoly SF, Quadri M, Van IJcken WFJ, Bonifati V, Gerwert K, Bohrmann B, Frank S, Britschgi M, Stahlberg H, Van de Berg WDJ, Lauer ME. Lewy pathology in Parkinson's disease consists of crowded organelles and lipid membranes. Nat Neurosci 2019; 22:1099-1109. [PMID: 31235907 DOI: 10.1038/s41593-019-0423-2] [Citation(s) in RCA: 492] [Impact Index Per Article: 98.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 05/09/2019] [Indexed: 12/17/2022]
Abstract
Parkinson's disease, the most common age-related movement disorder, is a progressive neurodegenerative disease with unclear etiology. Key neuropathological hallmarks are Lewy bodies and Lewy neurites: neuronal inclusions immunopositive for the protein α-synuclein. In-depth ultrastructural analysis of Lewy pathology is crucial to understanding pathogenesis of this disease. Using correlative light and electron microscopy and tomography on postmortem human brain tissue from Parkinson's disease brain donors, we identified α-synuclein immunopositive Lewy pathology and show a crowded environment of membranes therein, including vesicular structures and dysmorphic organelles. Filaments interspersed between the membranes and organelles were identifiable in many but not all α-synuclein inclusions. Crowding of organellar components was confirmed by stimulated emission depletion (STED)-based super-resolution microscopy, and high lipid content within α-synuclein immunopositive inclusions was corroborated by confocal imaging, Fourier-transform coherent anti-Stokes Raman scattering infrared imaging and lipidomics. Applying such correlative high-resolution imaging and biophysical approaches, we discovered an aggregated protein-lipid compartmentalization not previously described in the Parkinsons' disease brain.
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Affiliation(s)
- Sarah H Shahmoradian
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland.,Department of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Amanda J Lewis
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jürgen Hench
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Tim E Moors
- Amsterdam Neuroscience, VU University Medical Center, Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam, The Netherlands
| | - Paula P Navarro
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Daniel Castaño-Díez
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Gabriel Schweighauser
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | | | - Kenneth N Goldie
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Rosmarie Sütterlin
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Evelien Huisman
- Amsterdam Neuroscience, VU University Medical Center, Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam, The Netherlands
| | - Angela Ingrassia
- Amsterdam Neuroscience, VU University Medical Center, Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam, The Netherlands
| | - Yvonne de Gier
- Amsterdam Neuroscience, VU University Medical Center, Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam, The Netherlands
| | - Annemieke J M Rozemuller
- Amsterdam Neuroscience, VU University Medical Center, Department of Pathology, Amsterdam, The Netherlands
| | - Jing Wang
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Anne De Paepe
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Basel, Basel, Switzerland
| | - Johannes Erny
- Roche Pharma Research and Early Development, Preclinical CMC, Roche Innovation Center Basel, Basel, Switzerland
| | - Andreas Staempfli
- Roche Pharma Research and Early Development, Preclinical CMC, Roche Innovation Center Basel, Basel, Switzerland
| | - Joerg Hoernschemeyer
- Roche Pharma Research and Early Development, Preclinical CMC, Roche Innovation Center Basel, Basel, Switzerland
| | | | | | | | - Marialuisa Quadri
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Klaus Gerwert
- Department of Biophysics, Ruhr University, Bochum, Germany
| | - Bernd Bohrmann
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology, and Rare Diseases Discovery and Translational Area/Neuroscience Discovery, Roche Innovation Center Basel, Basel, Switzerland
| | - Stephan Frank
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Markus Britschgi
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology, and Rare Diseases Discovery and Translational Area/Neuroscience Discovery, Roche Innovation Center Basel, Basel, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland.
| | - Wilma D J Van de Berg
- Amsterdam Neuroscience, VU University Medical Center, Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam, The Netherlands.
| | - Matthias E Lauer
- Roche Pharma Research and Early Development, Lead Discovery, Roche Innovation Center Basel, Basel, Switzerland.
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14
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Genoud C, Titze B, Graff-Meyer A, Friedrich RW. Fast Homogeneous En Bloc Staining of Large Tissue Samples for Volume Electron Microscopy. Front Neuroanat 2018; 12:76. [PMID: 30323746 PMCID: PMC6172304 DOI: 10.3389/fnana.2018.00076] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/29/2018] [Indexed: 11/15/2022] Open
Abstract
Fixation and staining of large tissue samples are critical for the acquisition of volumetric electron microscopic image datasets and the subsequent reconstruction of neuronal circuits. Efficient protocols exist for the staining of small samples, but uniform contrast is often difficult to achieve when the sample diameter exceeds a few hundred micrometers. Recently, a protocol (BROPA, brain-wide reduced-osmium staining with pyrogallol-mediated amplification) was developed that achieves homogeneous staining of the entire mouse brain but requires very long sample preparation times. By exploring modifications of this protocol we developed a substantially faster procedure, fBROPA, that allows for reliable high-quality staining of tissue blocks on the millimeter scale. Modifications of the original BROPA protocol include drastically reduced incubation times and a lead aspartate incubation to increase sample conductivity. Using this procedure, whole brains from adult zebrafish were stained within 4 days. Homogenous high-contrast staining was achieved throughout the brain. High-quality image stacks with voxel sizes of 10 × 10 × 25 nm3 were obtained by serial block-face imaging using an electron dose of ~15 e−/nm2. No obvious reduction in staining quality was observed in comparison to smaller samples stained by other state-of-the-art procedures. Furthermore, high-quality images with minimal charging artifacts were obtained from non-neural tissues with low membrane density. fBROPA is therefore likely to be a versatile and efficient sample preparation protocol for a wide range of applications in volume electron microscopy.
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Affiliation(s)
- Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Benjamin Titze
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, Basel, Switzerland
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15
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Moretti F, Bergman P, Dodgson S, Marcellin D, Claerr I, Goodwin JM, DeJesus R, Kang Z, Antczak C, Begue D, Bonenfant D, Graff A, Genoud C, Reece‐Hoyes JS, Russ C, Yang Z, Hoffman GR, Mueller M, Murphy LO, Xavier RJ, Nyfeler B. TMEM41B is a novel regulator of autophagy and lipid mobilization. EMBO Rep 2018; 19:embr.201845889. [PMID: 30126924 PMCID: PMC6123663 DOI: 10.15252/embr.201845889] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 01/22/2023] Open
Abstract
Autophagy maintains cellular homeostasis by targeting damaged organelles, pathogens, or misfolded protein aggregates for lysosomal degradation. The autophagic process is initiated by the formation of autophagosomes, which can selectively enclose cargo via autophagy cargo receptors. A machinery of well-characterized autophagy-related proteins orchestrates the biogenesis of autophagosomes; however, the origin of the required membranes is incompletely understood. Here, we have applied sensitized pooled CRISPR screens and identify the uncharacterized transmembrane protein TMEM41B as a novel regulator of autophagy. In the absence of TMEM41B, autophagosome biogenesis is stalled, LC3 accumulates at WIPI2- and DFCP1-positive isolation membranes, and lysosomal flux of autophagy cargo receptors and intracellular bacteria is impaired. In addition to defective autophagy, TMEM41B knockout cells display significantly enlarged lipid droplets and reduced mobilization and β-oxidation of fatty acids. Immunostaining and interaction proteomics data suggest that TMEM41B localizes to the endoplasmic reticulum (ER). Taken together, we propose that TMEM41B is a novel ER-localized regulator of autophagosome biogenesis and lipid mobilization.
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Affiliation(s)
| | - Phil Bergman
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA
| | - Stacie Dodgson
- Harvard Medical SchoolMassachusetts General HospitalBostonMAUSA
| | | | | | - Jonathan M Goodwin
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA,Present address:
Casma TherapeuticsCambridgeMAUSA
| | - Rowena DeJesus
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA
| | - Zhao Kang
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA
| | | | - Damien Begue
- Novartis Institutes for BioMedical ResearchBaselSwitzerland
| | | | - Alexandra Graff
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | | | - Carsten Russ
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA
| | - Zinger Yang
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA
| | | | | | - Leon O Murphy
- Novartis Institutes for BioMedical ResearchCambridgeMAUSA,Present address:
Casma TherapeuticsCambridgeMAUSA
| | - Ramnik J Xavier
- Harvard Medical SchoolMassachusetts General HospitalBostonMAUSA
| | - Beat Nyfeler
- Novartis Institutes for BioMedical Research, Basel, Switzerland
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16
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Titze B, Genoud C, Friedrich RW. SBEMimage: Versatile Acquisition Control Software for Serial Block-Face Electron Microscopy. Front Neural Circuits 2018; 12:54. [PMID: 30108489 PMCID: PMC6079252 DOI: 10.3389/fncir.2018.00054] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/25/2018] [Indexed: 11/29/2022] Open
Abstract
We present SBEMimage, an open-source Python-based application to operate serial block-face electron microscopy (SBEM) systems. SBEMimage is designed for complex, challenging acquisition tasks, such as large-scale volume imaging of neuronal tissue or other biological ultrastructure. Advanced monitoring, process control, and error handling capabilities improve reliability, speed, and quality of acquisitions. Debris detection, autofocus, real-time image inspection, and various other quality control features minimize the risk of data loss during long-term acquisitions. Adaptive tile selection allows for efficient imaging of large tissue volumes of arbitrary shape. The software’s graphical user interface is optimized for remote operation. In its user-friendly viewport, tile grids covering the region of interest to be acquired are overlaid on previously acquired overview images of the sample surface. Images from other sources, e.g., light microscopes, can be imported and superimposed. SBEMimage complements existing DigitalMicrograph (Gatan Microscopy Suite) installations on 3View systems but permits higher acquisition rates by interacting directly with the microscope’s control software. Its modular architecture and the use of Python/PyQt make SBEMimage highly customizable and extensible, which allows for fast prototyping and will permit adaptation to a wide range of SBEM systems and applications.
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Affiliation(s)
- Benjamin Titze
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, Basel, Switzerland
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17
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Xue G, Kohler R, Tang F, Hynx D, Wang Y, Orso F, Prêtre V, Ritschard R, Hirschmann P, Cron P, Roloff T, Dummer R, Mandalà M, Bichet S, Genoud C, Meyer AG, Muraro MG, Spagnoli GC, Taverna D, Rüegg C, Merghoub T, Massi D, Tang H, Levesque MP, Dirnhofer S, Zippelius A, Hemmings BA, Wicki A. mTORC1/autophagy-regulated MerTK in mutant BRAFV600 melanoma with acquired resistance to BRAF inhibition. Oncotarget 2017; 8:69204-69218. [PMID: 29050198 PMCID: PMC5642473 DOI: 10.18632/oncotarget.18213] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/17/2017] [Indexed: 12/19/2022] Open
Abstract
BRAF inhibitors (BRAFi) and the combination therapy of BRAF and MEK inhibitors (MEKi) were recently approved for therapy of metastatic melanomas harbouring the oncogenic BRAFV600 mutation. Although these therapies have shown pronounced therapeutic efficacy, the limited durability of the response indicates an acquired drug resistance that still remains mechanistically poorly understood at the molecular level. We conducted transcriptome gene profiling in BRAFi-treated melanoma cells and identified that Mer tyrosine kinase (MerTK) is specifically upregulated. MerTK overexpression was demonstrated not only in melanomas resistant to BRAFi monotherapy (5 out of 10 samples from melanoma patients) but also in melanoma resistant to BRAFi+MEKi (1 out of 3), although MEKi alone does not affect MerTK. Mechanistically, BRAFi-induced activation of Zeb2 stimulates MerTK in BRAFV600 melanoma through mTORC1-triggered activation of autophagy. Co-targeting MerTK and BRAFV600 significantly reduced tumour burden in xenografted mice, which was pheno-copied by co-inhibition of autophagy and mutant BRAFV600.
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Affiliation(s)
- Gongda Xue
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Reto Kohler
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Fengyuan Tang
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Debby Hynx
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Yuhua Wang
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Francesca Orso
- Molecular Biotechnology Center and Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Vincent Prêtre
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Reto Ritschard
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | | | - Peter Cron
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Tim Roloff
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Reinhard Dummer
- Department of Dermatology, University Hospital of Zurich, Zurich, Switzerland
| | - Mario Mandalà
- Unit of Clinical and Translational Research, Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Sandrine Bichet
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Christel Genoud
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Alexandra G Meyer
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Manuele G Muraro
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Giulio C Spagnoli
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Daniela Taverna
- Molecular Biotechnology Center and Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Curzio Rüegg
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Taha Merghoub
- Ludwig Center for Cancer Immunotherapy, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Daniela Massi
- Division of Pathological Anatomy, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy
| | - Huifang Tang
- Department of Pharmacology, Zhejiang University, School of Basic Medical Sciences, Hangzhou, China
| | - Mitchell P Levesque
- Department of Dermatology, University Hospital of Zurich, Zurich, Switzerland
| | | | - Alfred Zippelius
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Brian A Hemmings
- Department of Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andreas Wicki
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
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18
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Heusermann W, Hean J, Trojer D, Steib E, von Bueren S, Graff-Meyer A, Genoud C, Martin K, Pizzato N, Voshol J, Morrissey DV, Andaloussi SEL, Wood MJ, Meisner-Kober NC. Exosomes surf on filopodia to enter cells at endocytic hot spots, traffic within endosomes, and are targeted to the ER. J Cell Biol 2017; 213:173-84. [PMID: 27114500 PMCID: PMC5084269 DOI: 10.1083/jcb.201506084] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/09/2016] [Indexed: 12/19/2022] Open
Abstract
Exosomes are nanovesicles released by virtually all cells, which act as intercellular messengers by transfer of protein, lipid, and RNA cargo. Their quantitative efficiency, routes of cell uptake, and subcellular fate within recipient cells remain elusive. We quantitatively characterize exosome cell uptake, which saturates with dose and time and reaches near 100% transduction efficiency at picomolar concentrations. Highly reminiscent of pathogenic bacteria and viruses, exosomes are recruited as single vesicles to the cell body by surfing on filopodia as well as filopodia grabbing and pulling motions to reach endocytic hot spots at the filopodial base. After internalization, exosomes shuttle within endocytic vesicles to scan the endoplasmic reticulum before being sorted into the lysosome as their final intracellular destination. Our data quantify and explain the efficiency of exosome internalization by recipient cells, establish a new parallel between exosome and virus host cell interaction, and suggest unanticipated routes of subcellular cargo delivery.
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Affiliation(s)
- Wolf Heusermann
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Justin Hean
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
| | - Dominic Trojer
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Emmanuelle Steib
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Stefan von Bueren
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Christel Genoud
- Friedrich-Miescher Institute for Biomedical Research, CH-4000 Basel, Switzerland
| | - Katrin Martin
- Department of Biomedicine, University of Basel, CH-4058 Basel, Switzerland
| | - Nicolas Pizzato
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Johannes Voshol
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Samir E L Andaloussi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK Department of Laboratory Medicine, Karolinska Institutet, SE-141 86 Huddinge, Sweden
| | - Matthew J Wood
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
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19
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Wanner AA, Genoud C, Friedrich RW. 3-dimensional electron microscopic imaging of the zebrafish olfactory bulb and dense reconstruction of neurons. Sci Data 2016; 3:160100. [PMID: 27824337 PMCID: PMC5100684 DOI: 10.1038/sdata.2016.100] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/22/2016] [Indexed: 01/27/2023] Open
Abstract
Large-scale reconstructions of neuronal populations are critical for structural analyses of neuronal cell types and circuits. Dense reconstructions of neurons from image data require ultrastructural resolution throughout large volumes, which can be achieved by automated volumetric electron microscopy (EM) techniques. We used serial block face scanning EM (SBEM) and conductive sample embedding to acquire an image stack from an olfactory bulb (OB) of a zebrafish larva at a voxel resolution of 9.25×9.25×25 nm3. Skeletons of 1,022 neurons, 98% of all neurons in the OB, were reconstructed by manual tracing and efficient error correction procedures. An ergonomic software package, PyKNOSSOS, was created in Python for data browsing, neuron tracing, synapse annotation, and visualization. The reconstructions allow for detailed analyses of morphology, projections and subcellular features of different neuron types. The high density of reconstructions enables geometrical and topological analyses of the OB circuitry. Image data can be accessed and viewed through the neurodata web services (http://www.neurodata.io). Raw data and reconstructions can be visualized in PyKNOSSOS.
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Affiliation(s)
- Adrian A. Wanner
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Rainer W. Friedrich
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
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20
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Titze B, Genoud C. Volume scanning electron microscopy for imaging biological ultrastructure. Biol Cell 2016; 108:307-323. [DOI: 10.1111/boc.201600024] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Benjamin Titze
- Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
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21
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Wanner AA, Genoud C, Masudi T, Siksou L, Friedrich RW. Dense EM-based reconstruction of the interglomerular projectome in the zebrafish olfactory bulb. Nat Neurosci 2016; 19:816-25. [PMID: 27089019 DOI: 10.1038/nn.4290] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
The dense reconstruction of neuronal circuits from volumetric electron microscopy (EM) data has the potential to uncover fundamental structure-function relationships in the brain. To address bottlenecks in the workflow of this emerging methodology, we developed a procedure for conductive sample embedding and a pipeline for neuron reconstruction. We reconstructed ∼98% of all neurons (>1,000) in the olfactory bulb of a zebrafish larva with high accuracy and annotated all synapses on subsets of neurons representing different types. The organization of the larval olfactory bulb showed marked differences from that of the adult but similarities to that of the insect antennal lobe. Interneurons comprised multiple types but granule cells were rare. Interglomerular projections of interneurons were complex and bidirectional. Projections were not random but biased toward glomerular groups receiving input from common types of sensory neurons. Hence, the interneuron network in the olfactory bulb exhibits a specific topological organization that is governed by glomerular identity.
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Affiliation(s)
- Adrian A Wanner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Tafheem Masudi
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Léa Siksou
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
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22
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Wanner AA, Kirschmann MA, Genoud C. Challenges of microtome-based serial block-face scanning electron microscopy in neuroscience. J Microsc 2015; 259:137-142. [PMID: 25907464 PMCID: PMC4745002 DOI: 10.1111/jmi.12244] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/11/2015] [Indexed: 01/14/2023]
Abstract
Serial block-face scanning electron microscopy (SBEM) is becoming increasingly popular for a wide range of applications in many disciplines from biology to material sciences. This review focuses on applications for circuit reconstruction in neuroscience, which is one of the major driving forces advancing SBEM. Neuronal circuit reconstruction poses exceptional challenges to volume EM in terms of resolution, field of view, acquisition time and sample preparation. Mapping the connections between neurons in the brain is crucial for understanding information flow and information processing in the brain. However, information on the connectivity between hundreds or even thousands of neurons densely packed in neuronal microcircuits is still largely missing. Volume EM techniques such as serial section TEM, automated tape-collecting ultramicrotome, focused ion-beam scanning electron microscopy and SBEM (microtome serial block-face scanning electron microscopy) are the techniques that provide sufficient resolution to resolve ultrastructural details such as synapses and provides sufficient field of view for dense reconstruction of neuronal circuits. While volume EM techniques are advancing, they are generating large data sets on the terabyte scale that require new image processing workflows and analysis tools. In this review, we present the recent advances in SBEM for circuit reconstruction in neuroscience and an overview of existing image processing and analysis pipelines.
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Affiliation(s)
- A A Wanner
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - M A Kirschmann
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - C Genoud
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
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23
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Genoud C, Houades V, Kraftsik R, Welker E, Giaume C. Proximity of excitatory synapses and astroglial gap junctions in layer IV of the mouse barrel cortex. Neuroscience 2015; 291:241-9. [PMID: 25681519 DOI: 10.1016/j.neuroscience.2015.01.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 12/27/2022]
Abstract
Neurons and astrocytes, the two major cell populations in the adult brain, are characterized by their own mode of intercellular communication--the synapses and the gap junctions (GJ), respectively. In addition, there is increasing evidence for dynamic and metabolic neuroglial interactions resulting in the modulation of synaptic transmission at the so-called "tripartite synapse". Based on this, we have investigated at the ultrastructural level how excitatory synapses (ES) and astroglial GJ are spatially distributed in layer IV of the barrel cortex of the adult mouse. We used specific antibodies for connexin (Cx) 30 and 43 to identify astroglial GJ, these two proteins are known to be present in the majority of astroglial GJ in the cerebral cortex. In electron-microscopic images, we measured the distance between two ES, between two GJ and between a GJ and its nearest ES. We found a ratio of two GJ per three ES in the hollow and septal areas. Taking into account the size of an astrocyte domain, the high density of GJ suggests the occurrence of reflexive type, i.e. GJ between processes of the same astrocyte. Interestingly, the distance between an ES and an astroglial GJ was found to be significantly lower than that between either two synapses or between two GJ. These observations indicate that the two modes of cell-to-cell communication are not randomly distributed in layer IV of the barrel cortex. Consequently, this feature may provide the morphological support for the recently reported functional interactions between neuronal circuits and astroglial networks.
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Affiliation(s)
- C Genoud
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - V Houades
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, France; Institut National de la Santé et de la Recherche Médicale U1050, 75231 Paris Cedex 05, France; University Pierre et Marie Curie, ED, N°158, 75005 Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, 75005 Paris, France
| | - R Kraftsik
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland
| | - E Welker
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland.
| | - C Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, France; Institut National de la Santé et de la Recherche Médicale U1050, 75231 Paris Cedex 05, France; University Pierre et Marie Curie, ED, N°158, 75005 Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, 75005 Paris, France.
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24
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Blumer C, Vivien C, Genoud C, Perez-Alvarez A, Wiegert JS, Vetter T, Oertner TG. Automated analysis of spine dynamics on live CA1 pyramidal cells. Med Image Anal 2015; 19:87-97. [DOI: 10.1016/j.media.2014.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/25/2014] [Accepted: 09/05/2014] [Indexed: 11/25/2022]
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25
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Abstract
Since electron microscopy (EM) first appeared in the 1930s, it has held centre stage as the primary tool for the exploration of biological structure. Yet, with the recent developments of light microscopy techniques that overcome the limitations imposed by the diffraction boundary, the question arises as to whether the importance of EM in on the wane. This Commentary describes some of the pioneering studies that have shaped our understanding of cell structure. These include the development of cryo-EM techniques that have given researchers the ability to capture images of native structures and at the molecular level. It also describes how a number of recent developments significantly increase the ability of EM to visualise biological systems across a range of length scales, and in 3D, ensuring that EM will remain at the forefront of biology research for the foreseeable future.
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Affiliation(s)
- Graham Knott
- BioEM Facility, Centre Interdisciplinaire de Microscopie Electronique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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26
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Busskamp V, Krol J, Nelidova D, Daum J, Szikra T, Tsuda B, Jüttner J, Farrow K, Scherf BG, Alvarez CPP, Genoud C, Sothilingam V, Tanimoto N, Stadler M, Seeliger M, Stoffel M, Filipowicz W, Roska B. miRNAs 182 and 183 are necessary to maintain adult cone photoreceptor outer segments and visual function. Neuron 2014; 83:586-600. [PMID: 25002228 DOI: 10.1016/j.neuron.2014.06.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2014] [Indexed: 12/31/2022]
Abstract
The outer segments of cones serve as light detectors for daylight color vision, and their dysfunction leads to human blindness conditions. We show that the cone-specific disruption of DGCR8 in adult mice led to the loss of miRNAs and the loss of outer segments, resulting in photoreceptors with significantly reduced light responses. However, the number of cones remained unchanged. The loss of the outer segments occurred gradually over 1 month, and during this time the genetic signature of cones decreased. Reexpression of the sensory-cell-specific miR-182 and miR-183 prevented outer segment loss. These miRNAs were also necessary and sufficient for the formation of inner segments, connecting cilia and short outer segments, as well as light responses in stem-cell-derived retinal cultures. Our results show that miR-182- and miR-183-regulated pathways are necessary for cone outer segment maintenance in vivo and functional outer segment formation in vitro.
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Affiliation(s)
- Volker Busskamp
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Jacek Krol
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Dasha Nelidova
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4058 Basel, Switzerland
| | - Janine Daum
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4058 Basel, Switzerland
| | - Tamas Szikra
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Ben Tsuda
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Josephine Jüttner
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Karl Farrow
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Brigitte Gross Scherf
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | | | - Christel Genoud
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Department of Ophthalmology, Eberhard-Karls University, 72076 Tübingen, Germany
| | - Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Department of Ophthalmology, Eberhard-Karls University, 72076 Tübingen, Germany
| | - Michael Stadler
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Mathias Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Department of Ophthalmology, Eberhard-Karls University, 72076 Tübingen, Germany
| | - Markus Stoffel
- Institute for Molecular Health Sciences, ETH, 8093 Zürich
| | - Witold Filipowicz
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4058 Basel, Switzerland.
| | - Botond Roska
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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27
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Kondo S, Bottos A, Allegood JC, Masson R, Maurer FG, Genoud C, Kaeser P, Huwiler A, Murakami M, Spiegel S, Hynes NE. Memo has a novel role in S1P signaling and is [corrected] crucial for vascular development. PLoS One 2014; 9:e94114. [PMID: 24714781 PMCID: PMC3979765 DOI: 10.1371/journal.pone.0094114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/13/2014] [Indexed: 11/24/2022] Open
Abstract
Memo is a conserved protein that was identified as an essential mediator of tumor cell motility induced by receptor tyrosine kinase activation. Here we show that Memo null mouse embryonic fibroblasts (MEFs) are impaired in PDGF-induced migration and this is due to a defect in sphingosine-1-phosphate (S1P) signaling. S1P is a bioactive phospholipid produced in response to multiple stimuli, which regulates many cellular processes. S1P is secreted to the extracellular milieu where it exerts its function by binding a family of G-protein coupled receptors (S1PRs), causing their activation in an autocrine or paracrine manner. The process, termed cell-autonomous S1PR signaling, plays a role in survival and migration. Indeed, PDGF uses cell-autonomous S1PR signaling to promote cell migration; we show here that this S1P pathway requires Memo. Using vascular endothelial cells (HUVECs) with Memo knock-down we show that their survival in conditions of serum-starvation is impaired. Furthermore, Memo loss in HUVECs causes a reduction of junctional VE-cadherin and an increase in sprout formation. Each of these phenotypes is rescued by S1P or S1P agonist addition, showing that Memo also plays an important role in cell-autonomous S1PR signaling in endothelial cells. We also produced conventional and endothelial cell-specific conditional Memo knock-out mouse strains and show that Memo is essential for embryonic development. Starting at E13.5 embryos of both strains display bleeding and other vascular problems, some of the phenotypes that have been described in mouse strains lacking S1PRs. The essential role of Memo in embryonic vascular development may be due in part to alterations in S1P signaling. Taken together our results show that Memo has a novel role in the S1P pathway and that Memo is needed to promote cell-autonomous S1PR activation.
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Affiliation(s)
- Shunya Kondo
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Alessia Bottos
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jeremy C. Allegood
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Regis Masson
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Patrick Kaeser
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Andrea Huwiler
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Masato Murakami
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Nancy E. Hynes
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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28
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Jayachandran R, Liu X, BoseDasgupta S, Müller P, Zhang CL, Moshous D, Studer V, Schneider J, Genoud C, Fossoud C, Gambino F, Khelfaoui M, Müller C, Bartholdi D, Rossez H, Stiess M, Houbaert X, Jaussi R, Frey D, Kammerer RA, Deupi X, de Villartay JP, Lüthi A, Humeau Y, Pieters J. Coronin 1 regulates cognition and behavior through modulation of cAMP/protein kinase A signaling. PLoS Biol 2014; 12:e1001820. [PMID: 24667537 PMCID: PMC3965382 DOI: 10.1371/journal.pbio.1001820] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 02/12/2014] [Indexed: 01/14/2023] Open
Abstract
The evolutionarily conserved protein coronin 1 is needed for activating the cyclic AMP signaling pathway in the brain and is important for cognition and behavior. Cognitive and behavioral disorders are thought to be a result of neuronal dysfunction, but the underlying molecular defects remain largely unknown. An important signaling pathway involved in the regulation of neuronal function is the cyclic AMP/Protein kinase A pathway. We here show an essential role for coronin 1, which is encoded in a genomic region associated with neurobehavioral dysfunction, in the modulation of cyclic AMP/PKA signaling. We found that coronin 1 is specifically expressed in excitatory but not inhibitory neurons and that coronin 1 deficiency results in loss of excitatory synapses and severe neurobehavioral disabilities, including reduced anxiety, social deficits, increased aggression, and learning defects. Electrophysiological analysis of excitatory synaptic transmission in amygdala revealed that coronin 1 was essential for cyclic–AMP–protein kinase A–dependent presynaptic plasticity. We further show that upon cell surface stimulation, coronin 1 interacted with the G protein subtype Gαs to stimulate the cAMP/PKA pathway. The absence of coronin 1 or expression of coronin 1 mutants unable to interact with Gαs resulted in a marked reduction in cAMP signaling. Strikingly, synaptic plasticity and behavioral defects of coronin 1–deficient mice were restored by in vivo infusion of a membrane-permeable cAMP analogue. Together these results identify coronin 1 as being important for cognition and behavior through its activity in promoting cAMP/PKA-dependent synaptic plasticity and may open novel avenues for the dissection of signal transduction pathways involved in neurobehavioral processes. Memory and behavior depend on the proper transduction of signals in the brain, but the underlying molecular mechanisms remain largely unknown. Coronin 1 is a member of a highly conserved family of proteins, and although its gene lies in a chromosome region associated with neurobehavioral dysfunction in mice and men, it has never been directly ascribed a specific function in the brain. Here we show that coronin 1 plays an important role in cognition and behavior by regulating the cyclic AMP (cAMP) signaling pathway. We find that when cell surface receptors are activated, coronin 1 stimulates cAMP production and activation of protein kinase A. Coronin 1 deficiency resulted in severe functional defects at excitatory synapses. Furthermore, in both mice and humans, deletion or mutation of coronin 1 causes severe neurobehavioral defects, including social deficits, increased aggression, and learning disabilities. Strikingly, treatment with a membrane-permeable analogue of cAMP restored synaptic plasticity and behavioral defects in mice lacking coronin 1. Together this work not only shows a critical role for coronin 1 in neurobehavior but also defines a role for the coronin family in regulating the transmission of signals within cells.
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Affiliation(s)
| | - Xiaolong Liu
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Chun-Lei Zhang
- Interdisciplinary Institute for Neuroscience, Bordeaux, France
| | | | - Vera Studer
- Biozentrum, University of Basel, Basel, Switzerland
| | - Jacques Schneider
- Department of Radiology, University Children Hospital, UKBB, Basel, Switzerland
| | - Christel Genoud
- Center for Cellular Imaging and NanoAnalytics, University of Basel, Basel, Switzerland
- Friedrich Miescher Institute, Basel, Switzerland
| | | | | | - Malik Khelfaoui
- Interdisciplinary Institute for Neuroscience, Bordeaux, France
| | | | | | | | | | - Xander Houbaert
- Interdisciplinary Institute for Neuroscience, Bordeaux, France
| | - Rolf Jaussi
- Biomolecular Research Laboratory, Paul Scherrer Institute, Villigen, Switzerland
| | - Daniel Frey
- Biomolecular Research Laboratory, Paul Scherrer Institute, Villigen, Switzerland
| | - Richard A. Kammerer
- Biomolecular Research Laboratory, Paul Scherrer Institute, Villigen, Switzerland
| | - Xavier Deupi
- Biomolecular Research Laboratory, Paul Scherrer Institute, Villigen, Switzerland
- Condensed Matter Theory, Paul Scherrer Institute, Villigen, Switzerland
| | | | | | - Yann Humeau
- Interdisciplinary Institute for Neuroscience, Bordeaux, France
- * E-mail: (Y.H.); (J.P.)
| | - Jean Pieters
- Biozentrum, University of Basel, Basel, Switzerland
- * E-mail: (Y.H.); (J.P.)
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29
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Abstract
Circadian oscillations in peripheral tissues, such as the retinal compartment of the eye, are critical to anticipating changing metabolic demands. Circadian shedding of retinal photoreceptor cell discs with subsequent phagocytosis by the neighboring retinal pigmented epithelium (RPE) is essential for removal of toxic metabolites and lifelong survival of these postmitotic neurons. Defects in photoreceptor phagocytosis can lead to severe retinal pathology, but the biochemical mechanisms remain poorly defined. By first documenting a 2.8-fold burst of photoreceptor phagocytosis events in the mouse eye in the morning compared with the afternoon by serial block face imaging, we established time points to assess transcriptional readouts by RNA sequencing (RNA-Seq). We identified 365 oscillating protein-coding transcripts that implicated the phosphoinositide lipid signaling network mediating the discrete steps of photoreceptor phagocytosis. Moreover, examination of overlapping cistromic sites by core clock transcription factors and promoter elements of these effector genes provided a functional basis for the circadian cycling of these transcripts. RNA-Seq also revealed oscillating expression of 16 long intergenic noncoding RNAs and key histone modifying enzymes critical for circadian gene expression. Our phenotypic and genotypic characterization reveals a complex global landscape of overlapping and temporally controlled networks driving the essential circadian process in the eye.
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Affiliation(s)
- Debarshi Mustafi
- 1Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4965, USA.
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30
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Proenca CC, Stoehr N, Bernhard M, Seger S, Genoud C, Roscic A, Paganetti P, Liu S, Murphy LO, Kuhn R, Bouwmeester T, Galimberti I. Atg4b-dependent autophagic flux alleviates Huntington's disease progression. PLoS One 2013; 8:e68357. [PMID: 23861892 PMCID: PMC3704647 DOI: 10.1371/journal.pone.0068357] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 05/29/2013] [Indexed: 01/24/2023] Open
Abstract
The accumulation of aggregated mutant huntingtin (mHtt) inclusion bodies is involved in Huntigton’s disease (HD) progression. Medium sized-spiny neurons (MSNs) in the corpus striatum are highly vulnerable to mHtt aggregate accumulation and degeneration, but the mechanisms and pathways involved remain elusive. Here we have developed a new model to study MSNs degeneration in the context of HD. We produced organotypic cortico-striatal slice cultures (CStS) from HD transgenic mice mimicking specific features of HD progression. We then show that induction of autophagy using catalytic inhibitors of mTOR prevents MSNs degeneration in HD CStS. Furthermore, disrupting autophagic flux by overexpressing Atg4b in neurons and slice cultures, accelerated mHtt aggregation and neuronal death, suggesting that Atg4b-dependent autophagic flux influences HD progression. Under these circumstances induction of autophagy using catalytic inhibitors of mTOR was inefficient and did not affect mHtt aggregate accumulation and toxicity, indicating that mTOR inhibition alleviates HD progression by inducing Atg4b-dependent autophagic flux. These results establish modulators of Atg4b-dependent autophagic flux as new potential targets in the treatment of HD.
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Affiliation(s)
- Catia C. Proenca
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Natacha Stoehr
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Mario Bernhard
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | | | | | | | - Shanming Liu
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Leon O. Murphy
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Tewis Bouwmeester
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Ivan Galimberti
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
- * E-mail:
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31
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Xiao L, Michalski N, Kronander E, Gjoni E, Genoud C, Knott G, Schneggenburger R. BMP signaling specifies the development of a large and fast CNS synapse. Nat Neurosci 2013; 16:856-64. [PMID: 23708139 DOI: 10.1038/nn.3414] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 05/02/2013] [Indexed: 11/09/2022]
Abstract
Large excitatory synapses with multiple active zones ensure reliable and fast information transfer at specific points in neuronal circuits. However, the mechanisms that determine synapse size in CNS circuits are largely unknown. Here we use the calyx of Held synapse, a major relay in the auditory system, to identify and study signaling pathways that specify large nerve terminal size and fast synaptic transmission. Using genome-wide screening, we identified bone morphogenetic proteins (BMPs) as candidate signaling molecules in the area of calyx synapses. Conditional deletion of BMP receptors in the auditory system of mice led to aberrations of synapse morphology and function specifically at the calyx of Held, with impaired nerve terminal growth, loss of monoinnervation and less mature transmitter release properties. Thus, BMP signaling specifies large and fast-transmitting synapses in the auditory system in a process that shares homologies with, but also extends beyond, retrograde BMP signaling at Drosophila neuromuscular synapses.
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Affiliation(s)
- Le Xiao
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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32
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Friedrich RW, Genoud C, Wanner AA. Analyzing the structure and function of neuronal circuits in zebrafish. Front Neural Circuits 2013; 7:71. [PMID: 23630467 PMCID: PMC3632777 DOI: 10.3389/fncir.2013.00071] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/03/2013] [Indexed: 11/13/2022] Open
Abstract
The clever choice of animal models has been instrumental for many breakthrough discoveries in life sciences. One of the outstanding challenges in neuroscience is the in-depth analysis of neuronal circuits to understand how interactions between large numbers of neurons give rise to the computational power of the brain. A promising model organism to address this challenge is the zebrafish, not only because it is cheap, transparent and accessible to sophisticated genetic manipulations but also because it offers unique advantages for quantitative analyses of circuit structure and function. One of the most important advantages of zebrafish is its small brain size, both at larval and adult stages. Small brains enable exhaustive measurements of neuronal activity patterns by optical imaging and facilitate large-scale reconstructions of wiring diagrams by electron microscopic approaches. Such information is important, and probably essential, to obtain mechanistic insights into neuronal computations underlying higher brain functions and dysfunctions. This review provides a brief overview over current methods and motivations for dense reconstructions of neuronal activity and connectivity patterns. It then discusses selective advantages of zebrafish and provides examples how these advantages are exploited to study neuronal computations in the olfactory bulb.
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33
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Zhang N, Kolesnikov AV, Jastrzebska B, Mustafi D, Sawada O, Maeda T, Genoud C, Engel A, Kefalov VJ, Palczewski K. Autosomal recessive retinitis pigmentosa E150K opsin mice exhibit photoreceptor disorganization. J Clin Invest 2012; 123:121-37. [PMID: 23221340 DOI: 10.1172/jci66176] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 10/04/2012] [Indexed: 12/13/2022] Open
Abstract
The pathophysiology of the E150K mutation in the rod opsin gene associated with autosomal recessive retinitis pigmentosa (arRP) has yet to be determined. We generated knock-in mice carrying a single nucleotide change in exon 2 of the rod opsin gene resulting in the E150K mutation. This novel mouse model displayed severe retinal degeneration affecting rhodopsin's stabilization of rod outer segments (ROS). Homozygous E150K (KK) mice exhibited early-onset retinal degeneration, with disorganized ROS structures, autofluorescent deposits in the subretinal space, and aberrant photoreceptor phagocytosis. Heterozygous (EK) mice displayed a delayed-onset milder retinal degeneration. Further, mutant receptors were mislocalized to the inner segments and perinuclear region. Though KK mouse rods displayed markedly decreased phototransduction, biochemical studies of the mutant rhodopsin revealed only minimally affected chromophore binding and G protein activation. Ablation of the chromophore by crossing KK mice with mice lacking the critical visual cycle protein LRAT slowed retinal degeneration, whereas blocking phototransduction by crossing KK mice with GNAT1-deficient mice slightly accelerated this process. This study highlights the importance of proper higher-order organization of rhodopsin in the native tissue and provides information about the signaling properties of this mutant rhodopsin. Additionally, these results suggest that patients heterozygous for the E150K mutation should be periodically reevaluated for delayed-onset retinal degeneration.
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Affiliation(s)
- Ning Zhang
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44160, USA
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34
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Abstract
Cellular senescence is the consequence of repetitive exposures to oxidative stress, perturbed energy homeostasis, accumulation of damaged proteins and lesions in their nucleic acids. Whereas mitotic cells are equipped with efficient cell replacement strategies; postmitotic neurons have--with a few exceptions--no mechanism to substitute dysfunctional cells within a complex neuronal network. Here we propose a potential strategy by which aging neurons contend against abnormal accumulation of damaged/misfolded proteins. The suggested mechanism involves the formation of 'budding-like' extrusions and their subsequent clearance by glia. This hypothesis emerged from our previous investigations of the aged hippocampus revealing layer-specific accumulations of Reelin, a glycoprotein with fundamental roles during brain development and adult synaptic plasticity. We showed that Reelin deposits constitute a conserved neuropathological feature of aging, which is significantly accelerated in adult wild-type mice prenatally exposed to a viral-like infection. Here, we employed two- and three-dimensional immunoelectron microscopy to elucidate their morphological properties, localization and origin in immune challenged vs. control mice. In controls, Reelin-positive deposits were dispersed in the neuropil, some being engulfed by glia. In immune challenged mice, however, significantly more Reelin-immunoreactive deposits were associated with neuritic swellings containing mitochondria, vacuoles and cellular debris, pointing to their intracellular origin and suggesting that 'budding-like' neuronal extrusions of misfolded proteins and glial clearance may represent a protective strategy to counteract aging-associated impairments in proteosomal/lysosomal degradation. Neurons exposed to chronic neuroinflammation with increased levels of misfolded/damaged proteins, however, may fail to combat intraneuronal protein accumulations, a process probably underlying neuronal dysfunction and degeneration during aging.
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Affiliation(s)
- Jana Doehner
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
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35
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Pinheiro I, Margueron R, Shukeir N, Eisold M, Fritzsch C, Richter FM, Mittler G, Genoud C, Goyama S, Kurokawa M, Son J, Reinberg D, Lachner M, Jenuwein T. Prdm3 and Prdm16 are H3K9me1 methyltransferases required for mammalian heterochromatin integrity. Cell 2012; 150:948-60. [PMID: 22939622 DOI: 10.1016/j.cell.2012.06.048] [Citation(s) in RCA: 226] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 04/19/2012] [Accepted: 06/26/2012] [Indexed: 01/08/2023]
Abstract
Heterochromatin serves important functions, protecting genome integrity and stabilizing gene expression programs. Although the Suv39h methyltransferases (KMTs) are known to ensure pericentric H3K9me3 methylation, the mechanisms that initiate and maintain mammalian heterochromatin organization remain elusive. We developed a biochemical assay and used in vivo analyses in mouse embryonic fibroblasts to identify Prdm3 and Prdm16 as redundant H3K9me1-specific KMTs that direct cytoplasmic H3K9me1 methylation. The H3K9me1 is converted in the nucleus to H3K9me3 by the Suv39h enzymes to reinforce heterochromatin. Simultaneous depletion of Prdm3 and Prdm16 abrogates H3K9me1 methylation, prevents Suv39h-dependent H3K9me3 trimethylation, and derepresses major satellite transcription. Most strikingly, DNA-FISH and electron microscopy reveal that combined impairment of Prdm3 and Prdm16 results in disintegration of heterochromatic foci and disruption of the nuclear lamina. Our data identify Prdm3 and Prdm16 as H3K9me1 methyltransferases and expose a functional framework in which anchoring to the nuclear periphery helps maintain the integrity of mammalian heterochromatin.
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Affiliation(s)
- Inês Pinheiro
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany
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36
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Miyasaka N, Wanner AA, Li J, Mack-Bucher J, Genoud C, Yoshihara Y, Friedrich RW. Functional development of the olfactory system in zebrafish. Mech Dev 2012; 130:336-46. [PMID: 23010553 DOI: 10.1016/j.mod.2012.09.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 11/29/2022]
Abstract
The olfactory system has become a popular model to study the function of neuronal circuits and the molecular and cellular mechanisms underlying the development of neurons and their connections. An excellent model to combine studies of function and development is the zebrafish because it not only permits sophisticated molecular and genetic analyses of development, but also functional measurements of neuronal activity patterns in the intact brain. This article reviews insights into the functional development of the olfactory system that have been obtained in zebrafish. The focus is on the specification of olfactory sensory neurons (OSNs), the mechanisms controlling odorant receptor expression and OSN identity, the pathfinding of OSN axons towards target glomeruli in the olfactory bulb (OB), the development of glomeruli and functional topographic maps in the OB, and the development of inhibitory interneurons in the OB.
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Affiliation(s)
- Nobuhiko Miyasaka
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan
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37
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Hoppa MB, Jones E, Karanauskaite J, Ramracheya R, Braun M, Collins SC, Zhang Q, Clark A, Eliasson L, Genoud C, MacDonald PE, Monteith AG, Barg S, Galvanovskis J, Rorsman P. Multivesicular exocytosis in rat pancreatic beta cells. Diabetologia 2012; 55:1001-12. [PMID: 22189485 PMCID: PMC3296018 DOI: 10.1007/s00125-011-2400-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 11/17/2011] [Indexed: 11/04/2022]
Abstract
AIMS/HYPOTHESIS To establish the occurrence, modulation and functional significance of compound exocytosis in insulin-secreting beta cells. METHODS Exocytosis was monitored in rat beta cells by electrophysiological, biochemical and optical methods. The functional assays were complemented by three-dimensional reconstruction of confocal imaging, transmission and block face scanning electron microscopy to obtain ultrastructural evidence of compound exocytosis. RESULTS Compound exocytosis contributed marginally (<5% of events) to exocytosis elicited by glucose/membrane depolarisation alone. However, in beta cells stimulated by a combination of glucose and the muscarinic agonist carbachol, 15-20% of the release events were due to multivesicular exocytosis, but the frequency of exocytosis was not affected. The optical measurements suggest that carbachol should stimulate insulin secretion by ∼40%, similar to the observed enhancement of glucose-induced insulin secretion. The effects of carbachol were mimicked by elevating [Ca(2+)](i) from 0.2 to 2 μmol/l Ca(2+). Two-photon sulforhodamine imaging revealed exocytotic events about fivefold larger than single vesicles and that these structures, once formed, could persist for tens of seconds. Cells exposed to carbachol for 30 s contained long (1-2 μm) serpentine-like membrane structures adjacent to the plasma membrane. Three-dimensional electron microscopy confirmed the existence of fused multigranular aggregates within the beta cell, the frequency of which increased about fourfold in response to stimulation with carbachol. CONCLUSIONS/INTERPRETATION Although contributing marginally to glucose-induced insulin secretion, compound exocytosis becomes quantitatively significant under conditions associated with global elevation of cytoplasmic calcium. These findings suggest that compound exocytosis is a major contributor to the augmentation of glucose-induced insulin secretion by muscarinic receptor activation.
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Affiliation(s)
- M. B. Hoppa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - E. Jones
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - J. Karanauskaite
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - R. Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - M. Braun
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - S. C. Collins
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - Q. Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - A. Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - L. Eliasson
- Lund University Diabetes Centre, Clinical Research Centre, Malmo, Sweden
| | - C. Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - P. E. MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, Canada
| | | | - S. Barg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - J. Galvanovskis
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
| | - P. Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ UK
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Motskin M, Müller KH, Genoud C, Monteith AG, Skepper JN. The sequestration of hydroxyapatite nanoparticles by human monocyte-macrophages in a compartment that allows free diffusion with the extracellular environment. Biomaterials 2011; 32:9470-82. [PMID: 21889202 DOI: 10.1016/j.biomaterials.2011.08.060] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 08/18/2011] [Indexed: 11/30/2022]
Abstract
Calcium phosphate and hydroxyapatite nanoparticles are extensively researched for medical applications, including bone implant materials, DNA and SiRNA delivery vectors and slow release vaccines. Elucidating the mechanisms by which cells internalize nanoparticles is fundamental for their long-term exploitation. In this study, we demonstrate that hydrophilic hydroxyapatite nanoparticles are sequestered within a specialized compartment called SCC (surface-connected compartment). This membrane-bound compartment is an elaborate labyrinth-like structure directly connected to the extracellular space. This continuity is demonstrated by in vivo 2-photon microscopy of ionic calcium using both cell-permeable and cell-impermeable dyes and by 3-D reconstructions from serial block-face SEM of fixed cells. Previously, this compartment was thought to be initiated specifically by exposure of macrophages to hydrophobic nanoparticles. However, we show that the SCC can be triggered by a much wider range of nanoparticles. Furthermore, we demonstrate its formation in A549 human lung epithelial cells, which are considerably less phagocytic than macrophages. EDX shows that extensive amounts of hydroxyapatite nanoparticles can be sequestered in this manner. We propose that SCC formation may be a means to remove large amounts of foreign material from the extracellular space, followed by slow degradation, may be to avoid excessive damage to surrounding cells or tissues.
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Affiliation(s)
- Michael Motskin
- Multi-Imaging Centre, Dept. of Physiology, Development and Neuroscience, Anatomy Building, Cambridge University, Cambridge CB2 3DY, UK
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39
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Mustafi D, Kevany BM, Genoud C, Okano K, Cideciyan AV, Sumaroka A, Roman AJ, Jacobson SG, Engel A, Adams MD, Palczewski K. Defective photoreceptor phagocytosis in a mouse model of enhanced S-cone syndrome causes progressive retinal degeneration. FASEB J 2011; 25:3157-76. [PMID: 21659555 PMCID: PMC3157681 DOI: 10.1096/fj.11-186767] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 05/26/2011] [Indexed: 11/11/2022]
Abstract
Enhanced S-cone syndrome (ESCS), featuring an excess number of S cones, manifests as a progressive retinal degeneration that leads to blindness. Here, through optical imaging, we identified an abnormal interface between photoreceptors and the retinal pigment epithelium (RPE) in 9 patients with ESCS. The neural retina leucine zipper transcription factor-knockout (Nrl(-/-)) mouse model demonstrates many phenotypic features of human ESCS, including unstable S-cone-positive photoreceptors. Using massively parallel RNA sequencing, we identified 6203 differentially expressed transcripts between wild-type (Wt) and Nrl(-/-) mouse retinas, with 6 highly significant differentially expressed genes of the Pax, Notch, and Wnt canonical pathways. Changes were also obvious in expression of 30 genes involved in the visual cycle and 3 key genes in photoreceptor phagocytosis. Novel high-resolution (100 nm) imaging and reconstruction of Nrl(-/-) retinas revealed an abnormal packing of photoreceptors that contributed to buildup of photoreceptor deposits. Furthermore, lack of phagosomes in the RPE layer of Nrl(-/-) retina revealed impairment in phagocytosis. Cultured RPE cells from Wt and Nrl(-/-) mice illustrated that the phagocytotic defect was attributable to the aberrant interface between ESCS photoreceptors and the RPE. Overcoming the retinal phagocytosis defect could arrest the progressive degenerative component of this disease.
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Affiliation(s)
- Debarshi Mustafi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965, USA.
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40
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Armer HEJ, Mariggi G, Png KMY, Genoud C, Monteith AG, Bushby AJ, Gerhardt H, Collinson LM. Imaging transient blood vessel fusion events in zebrafish by correlative volume electron microscopy. PLoS One 2009; 4:e7716. [PMID: 19893745 PMCID: PMC2769265 DOI: 10.1371/journal.pone.0007716] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 09/29/2009] [Indexed: 11/26/2022] Open
Abstract
The study of biological processes has become increasingly reliant on obtaining high-resolution spatial and temporal data through imaging techniques. As researchers demand molecular resolution of cellular events in the context of whole organisms, correlation of non-invasive live-organism imaging with electron microscopy in complex three-dimensional samples becomes critical. The developing blood vessels of vertebrates form a highly complex network which cannot be imaged at high resolution using traditional methods. Here we show that the point of fusion between growing blood vessels of transgenic zebrafish, identified in live confocal microscopy, can subsequently be traced through the structure of the organism using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) and Serial Block Face/Scanning Electron Microscopy (SBF/SEM). The resulting data give unprecedented microanatomical detail of the zebrafish and, for the first time, allow visualization of the ultrastructure of a time-limited biological event within the context of a whole organism.
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Affiliation(s)
- Hannah E. J. Armer
- Electron Microscopy Unit , London Research Institute, Cancer Research UK, London, United Kingdom
| | - Giovanni Mariggi
- Vascular Biology Laboratory, London Research Institute, Cancer Research UK, London, United Kingdom
| | - Ken M. Y. Png
- The Nanovision Centre, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Christel Genoud
- Electron Microscopy Facility, Friedrich Miescher Institute, Basel, Switzerland
| | | | - Andrew J. Bushby
- The Nanovision Centre, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Holger Gerhardt
- Vascular Biology Laboratory, London Research Institute, Cancer Research UK, London, United Kingdom
| | - Lucy M. Collinson
- Electron Microscopy Unit , London Research Institute, Cancer Research UK, London, United Kingdom
- * E-mail:
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Rouquette J, Genoud C, Vazquez-Nin GH, Kraus B, Cremer T, Fakan S. Revealing the high-resolution three-dimensional network of chromatin and interchromatin space: A novel electron-microscopic approach to reconstructing nuclear architecture. Chromosome Res 2009; 17:801-10. [DOI: 10.1007/s10577-009-9070-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 07/30/2009] [Indexed: 11/25/2022]
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Sacco CB, Tardif E, Genoud C, Probst A, Tolnay M, Janzer RC, Verney C, Kraftsik R, Clarke S. GABA receptor subunits in human auditory cortex in normal and stroke cases. Acta Neurobiol Exp (Wars) 2009; 69:469-93. [PMID: 20048764 DOI: 10.55782/ane-2009-1758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
GABA receptors are ubiquitous in the cerebral cortex and play a major role in shaping responses of cortical neurons. GABA(A) and GABA(B) receptor subunit expression was visualized by immunohistochemistry in human auditory areas from both hemispheres in 9 normal subjects (aged 43-85 years; time between death and fixation 6-24 hours) and in 4 stroke patients (aged 59-87 years; time between death and fixation 7-24 hours) and analyzed qualitatively for GABA(A) and semiquantitatively for GABA(B) receptor subunits. In normal brains, the primary auditory area (TC) and the surrounding areas TB and TA displayed distinct GABA(A) receptor subunit labeling with differences among cortical layers and areas. In postacute and chronic stroke we found a layer-selective downregulation of the alpha-2 subunit in the anatomically intact cerebral cortex of the intact and of the lesioned hemisphere, whereas the alpha-1, alpha-3 and beta-2/3 subunits maintained normal levels of expression. The GABA(B) receptors had a distinct laminar pattern in auditory areas and minor differences among areas. Unlike in other pathologies, there is no modulation of the GABA(B) receptor expression in subacute or chronic stroke.
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Affiliation(s)
- Carolyn B Sacco
- Neuropsychology and Neurorehabilitation Service, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
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Genoud C, Weller J. [Protocol for the evaluation and treatment of chronic wounds in the home care setting]. Praxis (Bern 1994) 2008; 97:317-321. [PMID: 18548939 DOI: 10.1024/1661-8157.97.6.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In 2001, it became evident that the domiciliary care nurses needed a tool to assist them in treating patients with chronic wounds. A protocol was therefore developed which could be used not only by the nurses but also by doctors and other health care professionals working in home care. As a parallel measure, a network of nurses specialised in wound care and available for advice and consultation was established.
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Affiliation(s)
- C Genoud
- Infirmières-stomathérapeutes et Infirmières Ressources en Plaies Chroniques, Centre Hospitalier Universitaire Vaudois et Organisme Médico-Social Vaudois, Lausanne.
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Genoud C, Quairiaux C, Steiner P, Hirling H, Welker E, Knott GW. Plasticity of astrocytic coverage and glutamate transporter expression in adult mouse cortex. PLoS Biol 2007; 4:e343. [PMID: 17048987 PMCID: PMC1609127 DOI: 10.1371/journal.pbio.0040343] [Citation(s) in RCA: 208] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 08/17/2006] [Indexed: 11/19/2022] Open
Abstract
Astrocytes play a major role in the removal of glutamate from the extracellular compartment. This clearance limits the glutamate receptor activation and affects the synaptic response. This function of the astrocyte is dependent on its positioning around the synapse, as well as on the level of expression of its high-affinity glutamate transporters, GLT1 and GLAST. Using Western blot analysis and serial section electron microscopy, we studied how a change in sensory activity affected these parameters in the adult cortex. Using mice, we found that 24 h of whisker stimulation elicited a 2-fold increase in the expression of GLT1 and GLAST in the corresponding cortical column of the barrel cortex. This returns to basal levels 4 d after the stimulation was stopped, whereas the expression of the neuronal glutamate transporter EAAC1 remained unaltered throughout. Ultrastructural analysis from the same region showed that sensory stimulation also causes a significant increase in the astrocytic envelopment of excitatory synapses on dendritic spines. We conclude that a period of modified neuronal activity and synaptic release of glutamate leads to an increased astrocytic coverage of the bouton-spine interface and an increase in glutamate transporter expression in astrocytic processes.
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Affiliation(s)
- Christel Genoud
- Départment de Biologie Cellulaire et de Morphologie, Lausanne, Switzerland
| | - Charles Quairiaux
- Départment de Biologie Cellulaire et de Morphologie, Lausanne, Switzerland
| | - Pascal Steiner
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Faculté des Sciences de la Vie, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Harald Hirling
- Faculté des Sciences de la Vie, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Egbert Welker
- Départment de Biologie Cellulaire et de Morphologie, Lausanne, Switzerland
| | - Graham W Knott
- Départment de Biologie Cellulaire et de Morphologie, Lausanne, Switzerland
- * To whom correspondence should be addressed. E-mail:
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Genoud C, Knott GW, Sakata K, Lu B, Welker E. Altered synapse formation in the adult somatosensory cortex of brain-derived neurotrophic factor heterozygote mice. J Neurosci 2004; 24:2394-400. [PMID: 15014114 PMCID: PMC6729494 DOI: 10.1523/jneurosci.4040-03.2004] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Increased sensory stimulation in the adult whisker-to-barrel pathway induces the expression of BDNF as well as synapse formation in cortical layer IV. Here, we investigated whether BDNF plays a role in the alterations of connectivity between neurons by analyzing the ultrastructure of the BDNF heterozygote mouse, characterized by a reduced level of BDNF expression. Using serial section electron microscopy, we measured synapse density, spine morphology, and synaptic vesicle distribution to show that mice with a reduced level of BDNF have a barrel neuropil that is indistinguishable from wild-type controls. After 24 hr of whisker stimulation, however, there is no indication of synapse formation in the heterozygous mouse. Whereas the balance between excitatory and inhibitory synapses is modified in the controls, it remains constant in the heterozygotes. The distribution of synaptic vesicles in excitatory synapses is the same in heterozygous and wild-type mice and is not influenced by the stimulation paradigm. Spine volume, however, is unchanged by stimulation in the wild-type animals, but does increase significantly in the heterozygous animal. These results provide evidence that, in vivo, BDNF plays an important role in the structural rearrangement of adult cortical circuitry as a consequence of an increased sensory input.
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Affiliation(s)
- Christel Genoud
- Institut de Biologie Cellulaire et de Morphologie, 1005 Lausanne, Switzerland
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Abstract
During development, alterations in sensory experience modify the structure of cortical neurons, particularly at the level of the dendritic spine. Are similar adaptations involved in plasticity of the adult cortex? Here we show that a 24 hr period of single whisker stimulation in freely moving adult mice increases, by 36%, the total synaptic density in the corresponding cortical barrel. This is due to an increase in both excitatory and inhibitory synapses found on spines. Four days after stimulation, the inhibitory inputs to the spines remain despite total synaptic density returning to pre-stimulation levels. Functional analysis of layer IV cells demonstrated altered response properties, immediately after stimulation, as well as four days later. These results indicate activity-dependent alterations in synaptic circuitry in adulthood, modifying the flow of sensory information into the cerebral cortex.
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Affiliation(s)
- Graham W Knott
- Institut de Biologie Cellulaire et Morphologie, Université de Lausanne, Rue du Bugnon 9, CH 1005, Lausanne, Switzerland
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