1
|
Hyenne V, Ghoroghi S, Collot M, Bons J, Follain G, Harlepp S, Mary B, Bauer J, Mercier L, Busnelli I, Lefebvre O, Fekonja N, Garcia-Leon MJ, Machado P, Delalande F, López AA, Silva SG, Verweij FJ, van Niel G, Djouad F, Peinado H, Carapito C, Klymchenko AS, Goetz JG. Studying the Fate of Tumor Extracellular Vesicles at High Spatiotemporal Resolution Using the Zebrafish Embryo. Dev Cell 2019; 48:554-572.e7. [PMID: 30745140 DOI: 10.1016/j.devcel.2019.01.014] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 10/19/2018] [Accepted: 01/10/2019] [Indexed: 01/08/2023]
Abstract
Tumor extracellular vesicles (EVs) mediate the communication between tumor and stromal cells mostly to the benefit of tumor progression. Notably, tumor EVs travel in the bloodstream, reach distant organs, and locally modify the microenvironment. However, visualizing these events in vivo still faces major hurdles. Here, we describe an approach for tracking circulating tumor EVs in a living organism: we combine chemical and genetically encoded probes with the zebrafish embryo as an animal model. We provide a first description of tumor EVs' hemodynamic behavior and document their intravascular arrest. We show that circulating tumor EVs are rapidly taken up by endothelial cells and blood patrolling macrophages and subsequently stored in degradative compartments. Finally, we demonstrate that tumor EVs activate macrophages and promote metastatic outgrowth. Overall, our study proves the usefulness and prospects of zebrafish embryo to track tumor EVs and dissect their role in metastatic niches formation in vivo.
Collapse
|
2
|
Tsang TK, Bushong EA, Boassa D, Hu J, Romoli B, Phan S, Dulcis D, Su CY, Ellisman MH. High-quality ultrastructural preservation using cryofixation for 3D electron microscopy of genetically labeled tissues. eLife 2018; 7:35524. [PMID: 29749931 PMCID: PMC5988420 DOI: 10.7554/elife.35524] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [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: 01/30/2018] [Accepted: 05/09/2018] [Indexed: 02/06/2023] Open
Abstract
Electron microscopy (EM) offers unparalleled power to study cell substructures at the nanoscale. Cryofixation by high-pressure freezing offers optimal morphological preservation, as it captures cellular structures instantaneously in their near-native state. However, the applicability of cryofixation is limited by its incompatibility with diaminobenzidine labeling using genetic EM tags and the high-contrast en bloc staining required for serial block-face scanning electron microscopy (SBEM). In addition, it is challenging to perform correlated light and electron microscopy (CLEM) with cryofixed samples. Consequently, these powerful methods cannot be applied to address questions requiring optimal morphological preservation. Here, we developed an approach that overcomes these limitations; it enables genetically labeled, cryofixed samples to be characterized with SBEM and 3D CLEM. Our approach is broadly applicable, as demonstrated in cultured cells, Drosophila olfactory organ and mouse brain. This optimization exploits the potential of cryofixation, allowing for quality ultrastructural preservation for diverse EM applications.
Collapse
Affiliation(s)
- Tin Ki Tsang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Eric A Bushong
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, United States
| | - Daniela Boassa
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, United States
| | - Junru Hu
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, United States
| | - Benedetto Romoli
- Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, United States
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, United States
| | - Davide Dulcis
- Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, United States
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, United States.,Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, United States
| |
Collapse
|
3
|
Wacker IU, Veith L, Spomer W, Hofmann A, Thaler M, Hillmer S, Gengenbach U, Schröder RR. Multimodal Hierarchical Imaging of Serial Sections for Finding Specific Cellular Targets within Large Volumes. J Vis Exp 2018:57059. [PMID: 29630046 PMCID: PMC5933231 DOI: 10.3791/57059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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] [Indexed: 01/23/2023] Open
Abstract
Targeting specific cells at ultrastructural resolution within a mixed cell population or a tissue can be achieved by hierarchical imaging using a combination of light and electron microscopy. Samples embedded in resin are sectioned into arrays consisting of ribbons of hundreds of ultrathin sections and deposited on pieces of silicon wafer or conductively coated coverslips. Arrays are imaged at low resolution using a digital consumer like smartphone camera or light microscope (LM) for a rapid large area overview, or a wide field fluorescence microscope (fluorescence light microscopy (FLM)) after labeling with fluorophores. After post-staining with heavy metals, arrays are imaged in a scanning electron microscope (SEM). Selection of targets is possible from 3D reconstructions generated by FLM or from 3D reconstructions made from the SEM image stacks at intermediate resolution if no fluorescent markers are available. For ultrastructural analysis, selected targets are finally recorded in the SEM at high-resolution (a few nanometer image pixels). A ribbon-handling tool that can be retrofitted to any ultramicrotome is demonstrated. It helps with array production and substrate removal from the sectioning knife boat. A software platform that allows automated imaging of arrays in the SEM is discussed. Compared to other methods generating large volume EM data, such as serial block-face SEM (SBF-SEM) or focused ion beam SEM (FIB-SEM), this approach has two major advantages: (1) The resin-embedded sample is conserved, albeit in a sliced-up version. It can be stained in different ways and imaged with different resolutions. (2) As the sections can be post-stained, it is not necessary to use samples strongly block-stained with heavy metals to introduce contrast for SEM imaging or render the tissue blocks conductive. This makes the method applicable to a wide variety of materials and biological questions. Particularly prefixed materials e.g., from biopsy banks and pathology labs, can directly be embedded and reconstructed in 3D.
Collapse
Affiliation(s)
- Irene U Wacker
- Cryo Electron Microscopy, Centre for Advanced Materials, Universität Heidelberg; Heidelberg Karlsruhe Research Partnership (HEiKA);
| | - Lisa Veith
- Cryo Electron Microscopy, BioQuant, Universitätsklinikum Heidelberg
| | - Waldemar Spomer
- Heidelberg Karlsruhe Research Partnership (HEiKA); Institute for Automation and Applied Computer Science, Karlsruhe Institute of Technology (KIT)
| | - Andreas Hofmann
- Heidelberg Karlsruhe Research Partnership (HEiKA); Institute for Automation and Applied Computer Science, Karlsruhe Institute of Technology (KIT)
| | | | - Stefan Hillmer
- Electron Microscopy Core Facility, Universität Heidelberg
| | - Ulrich Gengenbach
- Heidelberg Karlsruhe Research Partnership (HEiKA); Institute for Automation and Applied Computer Science, Karlsruhe Institute of Technology (KIT)
| | - Rasmus R Schröder
- Cryo Electron Microscopy, Centre for Advanced Materials, Universität Heidelberg; Heidelberg Karlsruhe Research Partnership (HEiKA); Cryo Electron Microscopy, BioQuant, Universitätsklinikum Heidelberg
| |
Collapse
|
4
|
Ilouz R, Lev-Ram V, Bushong EA, Stiles TL, Friedmann-Morvinski D, Douglas C, Goldberg JL, Ellisman MH, Taylor SS. Isoform-specific subcellular localization and function of protein kinase A identified by mosaic imaging of mouse brain. eLife 2017; 6:17681. [PMID: 28079521 PMCID: PMC5300705 DOI: 10.7554/elife.17681] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [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: 05/10/2016] [Accepted: 01/03/2017] [Indexed: 01/26/2023] Open
Abstract
Protein kinase A (PKA) plays critical roles in neuronal function that are mediated by different regulatory (R) subunits. Deficiency in either the RIβ or the RIIβ subunit results in distinct neuronal phenotypes. Although RIβ contributes to synaptic plasticity, it is the least studied isoform. Using isoform-specific antibodies, we generated high-resolution large-scale immunohistochemical mosaic images of mouse brain that provided global views of several brain regions, including the hippocampus and cerebellum. The isoforms concentrate in discrete brain regions, and we were able to zoom-in to show distinct patterns of subcellular localization. RIβ is enriched in dendrites and co-localizes with MAP2, whereas RIIβ is concentrated in axons. Using correlated light and electron microscopy, we confirmed the mitochondrial and nuclear localization of RIβ in cultured neurons. To show the functional significance of nuclear localization, we demonstrated that downregulation of RIβ, but not of RIIβ, decreased CREB phosphorylation. Our study reveals how PKA isoform specificity is defined by precise localization. DOI:http://dx.doi.org/10.7554/eLife.17681.001
Collapse
Affiliation(s)
- Ronit Ilouz
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Varda Lev-Ram
- Department of Pharmacology, University of California, San Diego, La Jolla, United States
| | - Eric A Bushong
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California, San Diego, San Diego, United States
| | - Travis L Stiles
- Department of Ophthalmology, Shiley Eye Center, University of California, San Diego, La Jolla, United States
| | - Dinorah Friedmann-Morvinski
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, United States.,Department of Biochemistry and Molecular Biology, George S Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Christopher Douglas
- Department of Ophthalmology, Shiley Eye Center, University of California, San Diego, La Jolla, United States
| | - Jeffrey L Goldberg
- Department of Ophthalmology, Shiley Eye Center, University of California, San Diego, La Jolla, United States
| | - Mark H Ellisman
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California, San Diego, San Diego, United States.,Department of Neurosciences, University of California, San Diego School of Medicine, La Jolla, United States
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, United States
| |
Collapse
|
5
|
Boassa D, Nguyen P, Hu J, Ellisman MH, Sosinsky GE. Pannexin2 oligomers localize in the membranes of endosomal vesicles in mammalian cells while Pannexin1 channels traffic to the plasma membrane. Front Cell Neurosci 2015; 8:468. [PMID: 25698922 PMCID: PMC4313697 DOI: 10.3389/fncel.2014.00468] [Citation(s) in RCA: 26] [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: 09/17/2014] [Accepted: 12/27/2014] [Indexed: 12/13/2022] Open
Abstract
Pannexin2 (Panx2) is the largest of three members of the pannexin proteins. Pannexins are topologically related to connexins and innexins, but serve different functional roles than forming gap junctions. We previously showed that pannexins form oligomeric channels but unlike connexins and innexins, they form only single membrane channels. High levels of Panx2 mRNA and protein in the Central Nervous System (CNS) have been documented. Whereas Pannexin1 (Panx1) is fairly ubiquitous and Pannexin3 (Panx3) is found in skin and connective tissue, both are fully glycosylated, traffic to the plasma membrane and have functions correlated with extracellular ATP release. Here, we describe trafficking and subcellular localizations of exogenous Panx2 and Panx1 protein expression in MDCK, HeLa, and HEK 293T cells as well as endogenous Panx1 and Panx2 patterns in the CNS. Panx2 was found in intracellular localizations, was partially N-glycosylated, and localizations were non-overlapping with Panx1. Confocal images of hippocampal sections immunolabeled for the astrocytic protein GFAP, Panx1 and Panx2 demonstrated that the two isoforms, Panx1 and Panx2, localized at different subcellular compartments in both astrocytes and neurons. Using recombinant fusions of Panx2 with appended genetic tags developed for correlated light and electron microscopy and then expressed in different cell lines, we determined that Panx2 is localized in the membrane of intracellular vesicles and not in the endoplasmic reticulum as initially indicated by calnexin colocalization experiments. Dual immunofluorescence imaging with protein markers for specific vesicle compartments showed that Panx2 vesicles are early endosomal in origin. In electron tomographic volumes, cross-sections of these vesicles displayed fine structural details and close proximity to actin filaments. Thus, pannexins expressed at different subcellular compartments likely exert distinct functional roles, particularly in the nervous system.
Collapse
Affiliation(s)
- Daniela Boassa
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Phuong Nguyen
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Junru Hu
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA ; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gina E Sosinsky
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA ; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
6
|
Pinault D, Smith Y, Deschênes M. Dendrodendritic and axoaxonic synapses in the thalamic reticular nucleus of the adult rat. J Neurosci 1997; 17:3215-33. [PMID: 9096155 PMCID: PMC6573646] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/1996] [Revised: 01/21/1997] [Accepted: 01/28/1997] [Indexed: 02/04/2023] Open
Abstract
Currently, it is believed that cell-cell communications occur in the thalamic reticular nucleus (RT) during thalamocortical operations, but the anatomical substrate underlying these intrinsic interactions has not been characterized fully in the rat yet. To further our knowledge on this issue, we stained juxtacellularly rat RT neurons with biocytin or Neurobiotin and examined their intrinsic axon collaterals and "axon-like processes" at both light and electron microscopic levels. Of 111 tracer-filled RT cells for which the axon could be followed from its origin up to the thalamus, 12 displayed short-range, poorly ramifying varicose local axon collaterals, which remained undistinguishable from parent distal dendrites, raising the question as to whether their varicosities were presynaptic terminals. Correlated light and electron microscopic observations of the proximal part of these intrinsic varicose axonal segments revealed that their varicosities and intervaricose segments were, in fact, postsynaptic structures contacted by a large number of boutons that, for the most, formed asymmetric synapses and were nonimmunoreactive for GABA. Similarly, the so-called "axon-like processes" stemming from the soma or dendrites also were identified as postsynaptic structures. Two unexpected observations were made in the course of this analysis. First, the hillock and initial segment of some RT axons were found to receive asymmetric synaptic inputs from GABA-negative terminals. Second, examination of serial ultrathin sections of dendritic bundles cut in their longitudinal plane revealed the existence of several short symmetric dendrodendritic synapses and numerous puncta adhaerentia between component dendrites. In conclusion, dendrodendritic junctions might be a prominent anatomical substrate underlying interneuronal communications in the RT of the adult rat. Furthermore, excitatory axoaxonic synapses on the axon hillock, initial segment, and local axon collaterals might represent a powerful synaptic drive for synchronizing the firing of RT neurons. Future studies are essential to verify whether excitatory axoaxonic synapses with the axon hillock are a general feature in the RT.
Collapse
Affiliation(s)
- D Pinault
- Centre de Recherche en Neurobiologie, Hôpital de l'Enfant-Jésus, Département de Physiologie, Faculté de Médecine, Université Laval, Québec, Canada, G1J 1Z4
| | | | | |
Collapse
|