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Limiting Neuronal Nogo Receptor 1 Signaling during Experimental Autoimmune Encephalomyelitis Preserves Axonal Transport and Abrogates Inflammatory Demyelination. J Neurosci 2019; 39:5562-5580. [PMID: 31061088 DOI: 10.1523/jneurosci.1760-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 04/05/2019] [Accepted: 04/29/2019] [Indexed: 11/21/2022] Open
Abstract
We previously identified that ngr1 allele deletion limits the severity of experimental autoimmune encephalomyelitis (EAE) by preserving axonal integrity. However, whether this favorable outcome observed in EAE is a consequence of an abrogated neuronal-specific pathophysiological mechanism, is yet to be defined. Here we show that, Cre-loxP-mediated neuron-specific deletion of ngr1 preserved axonal integrity, whereas its re-expression in ngr1-/- female mice potentiated EAE-axonopathy. As a corollary, myelin integrity was preserved under Cre deletion in ngr1flx/flx , retinal ganglion cell axons whereas, significant demyelination occurred in the ngr1-/- optic nerves following the re-introduction of NgR1. Moreover, Cre-loxP-mediated axon-specific deletion of ngr1 in ngr1flx/flx mice also demonstrated efficient anterograde transport of fluorescently-labeled ChTxβ in the optic nerves of EAE-induced mice. However, the anterograde transport of ChTxβ displayed accumulation in optic nerve degenerative axons of EAE-induced ngr1-/- mice, when NgR1 was reintroduced but was shown to be transported efficiently in the contralateral non- recombinant adeno-associated virus serotype 2-transduced optic nerves of these mutant mice. We further identified that the interaction between the axonal motor protein, Kinesin-1 and collapsin response mediator protein 2 (CRMP2) was unchanged upon Cre deletion of ngr1 Whereas, this Kinesin-1/CRMP2 association was reduced when NgR1 was re-expressed in the ngr1-/- optic nerves. Our data suggest that NgR1 governs axonal degeneration in the context of inflammatory-mediated demyelination through the phosphorylation of CRMP2 by stalling axonal vesicular transport. Moreover, axon-specific deletion of ngr1 preserves axonal transport mechanisms, blunting the induction of inflammatory demyelination and limiting the severity of EAE.SIGNIFICANCE STATEMENT Multiple sclerosis (MS) is commonly induced by aberrant immune-mediated destruction of the protective sheath of nerve fibers (known as myelin). However, it has been shown that MS lesions do not only consist of this disease pattern, exhibiting heterogeneity with continual destruction of axons. Here we investigate how neuronal NgR1 can drive inflammatory-mediated axonal degeneration and demyelination within the optic nerve by analyzing its downstream signaling events that govern axonal vesicular transport. We identify that abrogating the NgR1/pCRMP2 signaling cascade can maintain Kinesin-1-dependent anterograde axonal transport to limit inflammatory-mediated axonopathy and demyelination. The ability to differentiate between primary and secondary mechanisms of axonal degeneration may uncover therapeutic strategies to limit axonal damage and progressive MS.
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van Meel E, Bos E, van der Lienden MJC, Overkleeft HS, van Kasteren SI, Koster AJ, Aerts JMFG. Localization of active endogenous and exogenous β-glucocerebrosidase by correlative light-electron microscopy in human fibroblasts. Traffic 2019; 20:346-356. [PMID: 30895685 PMCID: PMC6519279 DOI: 10.1111/tra.12641] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 11/30/2022]
Abstract
β-Glucocerebrosidase (GBA) is the enzyme that degrades glucosylceramide in lysosomes. Defects in GBA that result in overall loss of enzymatic activity give rise to the lysosomal storage disorder Gaucher disease, which is characterized by the accumulation of glucosylceramide in tissue macrophages. Gaucher disease is currently treated by infusion of mannose receptor-targeted recombinant GBA. The recombinant GBA is thought to reach the lysosomes of macrophages, based on the impressive clinical response that is observed in Gaucher patients (type 1) receiving this enzyme replacement therapy. In this study, we used cyclophellitol-derived activity-based probes (ABPs) with a fluorescent reporter that irreversibly bind to the catalytic pocket of GBA, to visualize the active enzymes in a correlative microscopy approach. The uptake of pre-labeled recombinant enzyme was monitored by fluorescence and electron microscopy in human fibroblasts that stably expressed the mannose receptor. The endogenous active enzyme was simultaneously visualized by in situ labeling with the ABP containing an orthogonal fluorophore. This method revealed the efficient delivery of recombinant GBA to lysosomal target compartments that contained endogenous active enzyme.
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Affiliation(s)
- Eline van Meel
- Department of Medical Biochemistry, Leiden Institute of ChemistryLeiden UniversityLeidenthe Netherlands
| | - Erik Bos
- Department of Cell and Chemical BiologyLeiden University Medical CenterLeidenthe Netherlands
| | | | - Herman S. Overkleeft
- Department of Bio‐organic Synthesis, Leiden Institute of ChemistryLeiden UniversityLeidenthe Netherlands
| | - Sander I. van Kasteren
- Department of Bio‐organic Synthesis, Leiden Institute of ChemistryLeiden UniversityLeidenthe Netherlands
| | - Abraham J. Koster
- Department of Cell and Chemical BiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Johannes M. F. G. Aerts
- Department of Medical Biochemistry, Leiden Institute of ChemistryLeiden UniversityLeidenthe Netherlands
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Völkner M, Kurth T, Karl MO. The Mouse Retinal Organoid Trisection Recipe: Efficient Generation of 3D Retinal Tissue from Mouse Embryonic Stem Cells. Methods Mol Biol 2019; 1834:119-141. [PMID: 30324441 DOI: 10.1007/978-1-4939-8669-9_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
The introduction of stem cell-based technologies for the derivation of three-dimensional retinal tissues, the so-called retinal organoids, offers many new possibilities for vision research: Organoids facilitate studies on retinal development and in vitro retinal disease modeling, as well as being valuable for drug testing. Further, retinal organoids also provide an unlimited cell source for cell replacement therapies. Here, we describe our protocol for efficiently differentiating large, stratified retinal organoids from mouse embryonic stem cells: unbiased manual dissection of the developing retinal organoid at an early stage into three evenly sized neuroepithelial portions (trisection step) doubles the yield of high-quality organoids. We also describe some useful applications of the protocol, e.g., generation of rod- or cone-enriched retinal organoids, AAV transfection, and cell birth dating. In addition, we provide details of how to process retinal organoids for single organoid gene expression analysis, immunohistochemistry, and electron microscopy.
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Affiliation(s)
- Manuela Völkner
- German Center for Neurodegenerative Diseases Dresden (DZNE), Dresden, Germany
| | - Thomas Kurth
- Technische Universität Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Center for Regenerative Therapies Dresden (CRTD), Dresden, Germany
| | - Mike O Karl
- German Center for Neurodegenerative Diseases Dresden (DZNE), Dresden, Germany. .,Technische Universität Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Center for Regenerative Therapies Dresden (CRTD), Dresden, Germany.
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104
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Metal-Tagging Transmission Electron Microscopy and Immunogold Labeling on Tokuyasu Cryosections to Image Influenza A Virus Ribonucleoprotein Transport and Packaging. Methods Mol Biol 2019; 1836:281-301. [PMID: 30151579 DOI: 10.1007/978-1-4939-8678-1_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Transmission electron microscopy (TEM) has been instrumental for studying viral infections. In particular, methods for labeling macromolecules at the ultrastructural level, by integrating biochemistry, molecular biology, and morphology, have allowed to study the functions of viral macromolecular complexes within the cellular context. Here, we describe a strategy for imaging influenza virus ribonucleoproteins in infected cells with two complementary labeling methods, metal-tagging transmission electron microscopy or METTEM, a highly sensitive technique based on the use of a metal-binding protein as a clonable tag, and immunogold labeling on thawed cryosections, a very specific labeling method that allows to study the distribution of different proteins simultaneously. The combination of both labeling methods offers new possibilities for TEM analysis of viral components in cells.
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105
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Zhang M, Du Q, Yang F, Guo Y, Hou Y, Zhu P. Acupuncture at PC6 prevents cardiac hypertrophy in isoproterenol-treated mice. Acupunct Med 2019; 37:55-63. [PMID: 30843422 DOI: 10.1136/acupmed-2017-011418] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To investigate the effect of acupuncture at PC6 on cardiac hypertrophy in isoproterenol (ISO)-treated mice. METHODS 48 male C57BL/6 mice underwent subcutaneous injection of ISO for 14 days and were randomly divided into four groups (n=12 each) that remained untreated (ISO group), received verum manual acupuncture (MA) treatment at PC6 (ISO+MA(PC6) group), sham MA at location on the tail not corresponding to any traditional acupuncture point (ISO+MA(tail) group), or propranolol (ISO+PR group). An additional 12 mice were given an injection of phosphate-buffered saline (PBS) and formed a healthy control (Normal) group. After performing echocardiography and measuring the ratio of heart weight (HW)/tibia length (TL) at 14 days, all mice were euthanased. Morphological examination was performed following haematoxylin and eosin and Masson's staining of heart tissues. Ultrastructural changes were observed by electron microscopy. Cardiac protein expression of atrial natriuretic peptide (ANP) and tumour necrosis factor α (TNFα) were measured by immunohistochemical (IHC) staining and Western blotting. RESULTS Compared with the untreated model group, acupuncture at PC6 lowered the heart rate, reduced the ratio of HW/TL, improved the left ventricular (LV) anterior wall thickness (LVAWd), LV end-diastolic anterior wall thickness (LVAWs), LV end-systolic posterior wall thickness (LVPWd), LV end-diastolic posterior wall thickness (LVPWs), and fractional shortening (FS) as observed by echocardiography (ISO+MA(PC6) vs. ISO groups: P<0.05). Moreover, evidence from morphological studies demonstrated that acupuncture at PC6 inhibited myocardial hypertrophy and collagen deposition, and normalised the ultrastructural changes. In addition, ANP and TNFα expression were attenuated in the verum acupuncture group compared with the untreated model group (ISO+MA(PC6) vs. ISO groups: P<0.05). CONCLUSIONS The results demonstrated that acupuncture at PC6 attenuates sympathetic overactivity. Additionally, it may improve cardiac performance by reversing adverse cardiac remodelling. Acupuncture has potential as a treatment for sympathetic hypertension.
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Affiliation(s)
- Miao Zhang
- 1 Second Affiliated Hospital of Heilongjiang TCM University, Harbin, China
| | - Qigen Du
- 1 Second Affiliated Hospital of Heilongjiang TCM University, Harbin, China
| | - Fubiao Yang
- 2 Department of Medical Affairs, Heilongjiang TCM University, Harbin, China
| | - Ying Guo
- 1 Second Affiliated Hospital of Heilongjiang TCM University, Harbin, China
| | - Yunlong Hou
- 3 Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Pengyu Zhu
- 1 Second Affiliated Hospital of Heilongjiang TCM University, Harbin, China
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Inflammation-Induced Epithelial-to-Mesenchymal Transition and GM-CSF Treatment Stimulate Mesenteric Mesothelial Cells to Transdifferentiate into Macrophages. Inflammation 2019; 41:1825-1834. [PMID: 29911275 DOI: 10.1007/s10753-018-0825-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In our previous work, we showed that during inflammation-induced epithelial-to-mesenchymal transition (EMT), mesenteric mesothelial cells express ED1 (pan-macrophage marker), indicating that they are transformed into macrophage-like cells. In this paper, we provide additional evidences about this transition by following the phagocytic activity and the TNFα production of mesenteric mesothelial cells during inflammation. Upon injection of India ink particles or fluorescent-labeled bioparticles (pHrodo) into the peritoneal cavity of rats pretreated with Freund's adjuvant, we found that mesothelial cells efficiently engulfed these particles. A similar increase of internalization could be observed by mesothelial cells in GM-CSF pretreated primary mesenteric culture. Since macrophages are the major producers of tumor necrosis factor, TNFα, we investigated expression level of TNFα during inflammation-induced EMT and found that TNFα was indeed expressed in these cells, reaching the highest level at the 5th day of inflammation. Since TNFα is one of the target genes of early growth response (EGR1) transcription factor, playing important role in monocyte-macrophage differentiation, expression of EGR1 in mesothelial cells was also investigated by Western blot and immunocytochemistry. While mesothelial cells did not express EGR1, a marked increase was observed in mesothelial cells by the time of inflammation. Parallel to this, nuclear translocation of EGR1 was shown by immunocytochemistry at the day 5 of inflammation. Caveolin-1 level was high and ERK1/2 became phosphorylated as the inflammation proceeded showing a slight decrease when the regeneration started. Our present data support the idea that under special stimuli, mesenteric mesothelial cells are able to transdifferentiate into macrophages, and this transition is regulated by the caveolin-1/ERK1/2/EGR1 signaling pathway.
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Weil MT, Ruhwedel T, Meschkat M, Sadowski B, Möbius W. Transmission Electron Microscopy of Oligodendrocytes and Myelin. Methods Mol Biol 2019; 1936:343-375. [PMID: 30820909 DOI: 10.1007/978-1-4939-9072-6_20] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this chapter, we describe protocols to study different aspects of oligodendrocytes and myelin using electron microscopy. First, we describe in detail how to prepare central nervous system tissue routinely by perfusion fixation of the animal and conventional embedding in Epon resin. Then, we explain how, with some modifications, chemically fixed tissue can be used for immunoelectron microscopy on cryosections. Chemical fixation and Epon embedding can also be applied to purified myelin to assess the quality of the preparation. Furthermore, we describe how cryopreparation by high-pressure freezing can be used to study the fine structure of myelin in nerve, brain, and spinal cord tissue. The differences in the structural appearance of oligodendrocytes and myelin between cryopreserved and conventionally processed samples are compared using representative images. Since primary cultured oligodendrocytes are used to study structure and function in vitro, we provide protocols for chemical fixation and Epon embedding of these cultures. Finally, we explain how the cytoskeleton of cultured oligodendrocytes can be visualized by using transmission electron microscopy on platinum-carbon replicas. In this chapter, we provide a wide range of protocols that can be applied to shed light on the different biological aspects of myelin and oligodendrocytes.
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Affiliation(s)
- Marie-Theres Weil
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Electron Microscopy Core Unit, Göttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,AbbVie Deutschland GmbH and Co. KG, Ludwigshafen, Germany
| | - Torben Ruhwedel
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Electron Microscopy Core Unit, Göttingen, Germany
| | - Martin Meschkat
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Electron Microscopy Core Unit, Göttingen, Germany
| | - Boguslawa Sadowski
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Electron Microscopy Core Unit, Göttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Wiebke Möbius
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Electron Microscopy Core Unit, Göttingen, Germany. .,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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Nauth T, Huschka F, Schweizer M, Bosse JB, Diepold A, Failla AV, Steffen A, Stradal TEB, Wolters M, Aepfelbacher M. Visualization of translocons in Yersinia type III protein secretion machines during host cell infection. PLoS Pathog 2018; 14:e1007527. [PMID: 30586431 PMCID: PMC6324820 DOI: 10.1371/journal.ppat.1007527] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/08/2019] [Accepted: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
Type III secretion systems (T3SSs) are essential virulence factors of numerous bacterial pathogens. Upon host cell contact the T3SS machinery—also named injectisome—assembles a pore complex/translocon within host cell membranes that serves as an entry gate for the bacterial effectors. Whether and how translocons are physically connected to injectisome needles, whether their phenotype is related to the level of effector translocation and which target cell factors trigger their formation have remained unclear. We employed the superresolution fluorescence microscopy techniques Stimulated Emission Depletion (STED) and Structured Illumination Microscopy (SIM) as well as immunogold electron microscopy to visualize Y. enterocolitica translocons during infection of different target cell types. Thereby we were able to resolve translocon and needle complex proteins within the same injectisomes and demonstrate that these fully assembled injectisomes are generated in a prevacuole, a PI(4,5)P2 enriched host cell compartment inaccessible to large extracellular proteins like antibodies. Furthermore, the operable translocons were produced by the yersiniae to a much larger degree in macrophages (up to 25% of bacteria) than in HeLa cells (2% of bacteria). However, when the Rho GTPase Rac1 was activated in the HeLa cells, uptake of the yersiniae into the prevacuole, translocon formation and effector translocation were strongly enhanced reaching the same levels as in macrophages. Our findings indicate that operable T3SS translocons can be visualized as part of fully assembled injectisomes with superresolution fluorescence microscopy techniques. By using this technology, we provide novel information about the spatiotemporal organization of T3SS translocons and their regulation by host cell factors. Many human, animal and plant pathogenic bacteria employ a molecular machine termed injectisome to inject their toxins into host cells. Because injectisomes are crucial for these bacteria’s infectious potential they have been considered as targets for antiinfective drugs. Injectisomes are highly similar between the different bacterial pathogens and most of their overall structure is well established at the molecular level. However, only little information is available for a central part of the injectisome named the translocon. This pore-like assembly integrates into host cell membranes and thereby serves as an entry gate for the bacterial toxins. We used state of the art fluorescence microscopy to watch translocons of the diarrheagenic pathogen Yersinia enterocolitica during infection of human host cells. Thereby we could for the first time—with fluorescence microscopy—visualize translocons connected to other parts of the injectisome. Furthermore, because translocons mark functional injectisomes we could obtain evidence that injectisomes only become active for secretion of translocators when the bacteria are almost completely enclosed by host cells. These findings provide a novel view on the organization and regulation of bacterial translocons and may thus open up new strategies to block the function of infectious bacteria.
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Affiliation(s)
- Theresa Nauth
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Franziska Huschka
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Jens B. Bosse
- Heinrich-Pette-Institute (HPI), Leibniz-Institute for Experimental Virology, Hamburg, Germany
| | - Andreas Diepold
- Department of Ecophysiology, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Antonio Virgilio Failla
- UKE Microscopy Imaging Facility, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Theresia E. B. Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Manuel Wolters
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Martin Aepfelbacher
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- * E-mail:
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Xu X, Xu J, Wu J, Hu Y, Han Y, Gu Y, Zhao K, Zhang Q, Liu X, Liu J, Liu B, Cao X. Phosphorylation-Mediated IFN-γR2 Membrane Translocation Is Required to Activate Macrophage Innate Response. Cell 2018; 175:1336-1351.e17. [PMID: 30318148 DOI: 10.1016/j.cell.2018.09.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 08/04/2018] [Accepted: 09/07/2018] [Indexed: 01/20/2023]
Abstract
As a critical step during innate response, the cytoplasmic β subunit (IFN-γR2) of interferon-γ receptor (IFN-γR) is induced and translocates to plasma membrane to join α subunit to form functional IFN-γR to mediate IFN-γ signaling. However, the mechanism driving membrane translocation and its significance remain largely unknown. We found, unexpectedly, that mice deficient in E-selectin, an endothelial cell-specific adhesion molecule, displayed impaired innate activation of macrophages upon Listeria monocytogenes infection yet had increased circulating IFN-γ. Inflammatory macrophages from E-selectin-deficient mice had less surface IFN-γR2 and impaired IFN-γ signaling. BTK elicited by extrinsic E-selectin engagement phosphorylates cytoplasmic IFN-γR2, facilitating EFhd2 binding and promoting IFN-γR2 trafficking from Golgi to cell membrane. Our findings demonstrate that membrane translocation of cytoplasmic IFN-γR2 is required to activate macrophage innate response against intracellular bacterial infection, identifying the assembly of functional cytokine receptors on cell membrane as an important layer in innate activation and cytokine signaling.
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Affiliation(s)
- Xiaoqing Xu
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China; National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Jia Xu
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China
| | - Jiacheng Wu
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China
| | - Ye Hu
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China
| | - Yanmei Han
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Yan Gu
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Kai Zhao
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China
| | - Qian Zhang
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Xingguang Liu
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Juan Liu
- National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China
| | - Bing Liu
- Translational Medicine Center, Academy of Military Medical Sciences, 100024 Beijing, China
| | - Xuetao Cao
- Department of Immunology and Center for Immunotherapy, Institute of Basic Medical Sciences, Peking Union Medical College, Chinese Academy of Medical Sciences, 100005 Beijing, China; National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, 200433 Shanghai, China; College of Life Science, Nankai University, 300071 Tianjin, China.
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Ifie E, Russell MA, Dhayal S, Leete P, Sebastiani G, Nigi L, Dotta F, Marjomäki V, Eizirik DL, Morgan NG, Richardson SJ. Unexpected subcellular distribution of a specific isoform of the Coxsackie and adenovirus receptor, CAR-SIV, in human pancreatic beta cells. Diabetologia 2018; 61:2344-2355. [PMID: 30074059 PMCID: PMC6182664 DOI: 10.1007/s00125-018-4704-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 07/02/2018] [Indexed: 12/16/2022]
Abstract
AIMS/HYPOTHESIS The Coxsackie and adenovirus receptor (CAR) is a transmembrane cell-adhesion protein that serves as an entry receptor for enteroviruses and may be essential for their ability to infect cells. Since enteroviral infection of beta cells has been implicated as a factor that could contribute to the development of type 1 diabetes, it is often assumed that CAR is displayed on the surface of human beta cells. However, CAR exists as multiple isoforms and it is not known whether all isoforms subserve similar physiological functions. In the present study, we have determined the profile of CAR isoforms present in human beta cells and monitored the subcellular localisation of the principal isoform within the cells. METHODS Formalin-fixed, paraffin-embedded pancreatic sections from non-diabetic individuals and those with type 1 diabetes were studied. Immunohistochemistry, confocal immunofluorescence, electron microscopy and western blotting with isoform-specific antisera were employed to examine the expression and cellular localisation of the five known CAR isoforms. Isoform-specific qRT-PCR and RNA sequencing (RNAseq) were performed on RNA extracted from isolated human islets. RESULTS An isoform of CAR with a terminal SIV motif and a unique PDZ-binding domain was expressed at high levels in human beta cells at the protein level. A second isoform, CAR-TVV, was also present. Both forms were readily detected by qRT-PCR and RNAseq analysis in isolated human islets. Immunocytochemical studies indicated that CAR-SIV was the principal isoform in islets and was localised mainly within the cytoplasm of beta cells, rather than at the plasma membrane. Within the cells it displayed a punctate pattern of immunolabelling, consistent with its retention within a specific membrane-bound compartment. Co-immunofluorescence analysis revealed significant co-localisation of CAR-SIV with zinc transporter protein 8 (ZnT8), prohormone convertase 1/3 (PC1/3) and insulin, but not proinsulin. This suggests that CAR-SIV may be resident mainly in the membranes of insulin secretory granules. Immunogold labelling and electron microscopic analysis confirmed that CAR-SIV was localised to dense-core (insulin) secretory granules in human islets, whereas no immunolabelling of the protein was detected on the secretory granules of adjacent exocrine cells. Importantly, CAR-SIV was also found to co-localise with protein interacting with C-kinase 1 (PICK1), a protein recently demonstrated to play a role in insulin granule maturation and trafficking. CONCLUSIONS/INTERPRETATION The SIV isoform of CAR is abundant in human beta cells and is localised mainly to insulin secretory granules, implying that it may be involved in granule trafficking and maturation. We propose that this subcellular localisation of CAR-SIV contributes to the unique sensitivity of human beta cells to enteroviral infection.
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Affiliation(s)
- Eseoghene Ifie
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK
| | - Mark A Russell
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK
| | - Shalinee Dhayal
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK
| | - Pia Leete
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK
| | - Guido Sebastiani
- Department of Medicine, Surgery and Neurosciences, University of Siena and Fondazione Umberto Di Mario ONLUS-Toscana Life Sciences, Siena, Italy
| | - Laura Nigi
- Department of Medicine, Surgery and Neurosciences, University of Siena and Fondazione Umberto Di Mario ONLUS-Toscana Life Sciences, Siena, Italy
| | - Francesco Dotta
- Department of Medicine, Surgery and Neurosciences, University of Siena and Fondazione Umberto Di Mario ONLUS-Toscana Life Sciences, Siena, Italy
| | - Varpu Marjomäki
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Decio L Eizirik
- Université Libre de Bruxelles (ULB) Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Noel G Morgan
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK
| | - Sarah J Richardson
- Islet Biology Exeter (IBEx), Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, RILD Building (Level 4), Barrack Road, Exeter, EX2 5DW, UK.
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Changes in the Synaptic Proteome in Tauopathy and Rescue of Tau-Induced Synapse Loss by C1q Antibodies. Neuron 2018; 100:1322-1336.e7. [PMID: 30392797 DOI: 10.1016/j.neuron.2018.10.014] [Citation(s) in RCA: 287] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/15/2018] [Accepted: 10/05/2018] [Indexed: 12/19/2022]
Abstract
Synapse loss and Tau pathology are hallmarks of Alzheimer's disease (AD) and other tauopathies, but how Tau pathology causes synapse loss is unclear. We used unbiased proteomic analysis of postsynaptic densities (PSDs) in Tau-P301S transgenic mice to identify Tau-dependent alterations in synapses prior to overt neurodegeneration. Multiple proteins and pathways were altered in Tau-P301S PSDs, including depletion of a set of GTPase-regulatory proteins that leads to actin cytoskeletal defects and loss of dendritic spines. Furthermore, we found striking accumulation of complement C1q in the PSDs of Tau-P301S mice and AD patients. At synapses, C1q decorated perisynaptic membranes, accumulated in correlation with phospho-Tau, and was associated with augmented microglial engulfment of synapses and decline of synapse density. A C1q-blocking antibody inhibited microglial synapse removal in cultured neurons and in Tau-P301S mice, rescuing synapse density. Thus, inhibiting complement-mediated synapse removal by microglia could be a potential therapeutic target for Tau-associated neurodegeneration.
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112
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Lahaye X, Gentili M, Silvin A, Conrad C, Picard L, Jouve M, Zueva E, Maurin M, Nadalin F, Knott GJ, Zhao B, Du F, Rio M, Amiel J, Fox AH, Li P, Etienne L, Bond CS, Colleaux L, Manel N. NONO Detects the Nuclear HIV Capsid to Promote cGAS-Mediated Innate Immune Activation. Cell 2018; 175:488-501.e22. [PMID: 30270045 DOI: 10.1016/j.cell.2018.08.062] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 07/05/2018] [Accepted: 08/28/2018] [Indexed: 12/26/2022]
Abstract
Detection of viruses by innate immune sensors induces protective antiviral immunity. The viral DNA sensor cyclic GMP-AMP synthase (cGAS) is necessary for detection of HIV by human dendritic cells and macrophages. However, synthesis of HIV DNA during infection is not sufficient for immune activation. The capsid protein, which associates with viral DNA, has a pivotal role in enabling cGAS-mediated immune activation. We now find that NONO is an essential sensor of the HIV capsid in the nucleus. NONO protein directly binds capsid with higher affinity for weakly pathogenic HIV-2 than highly pathogenic HIV-1. Upon infection, NONO is essential for cGAS activation by HIV and cGAS association with HIV DNA in the nucleus. NONO recognizes a conserved region in HIV capsid with limited tolerance for escape mutations. Detection of nuclear viral capsid by NONO to promote DNA sensing by cGAS reveals an innate strategy to achieve distinction of viruses from self in the nucleus.
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Affiliation(s)
- Xavier Lahaye
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Matteo Gentili
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Aymeric Silvin
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Cécile Conrad
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Léa Picard
- CIRI-International Center for Infectiology Research, Inserm U1111, CNRS UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Univ Lyon, 69007 Lyon, France; LBBE-Laboratoire de Biométrie et Biologie Evolutive CNRS UMR 5558, Universite Lyon 1, Univ Lyon, 69622 Villeurbanne, France
| | - Mabel Jouve
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Elina Zueva
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Mathieu Maurin
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Francesca Nadalin
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Gavin J Knott
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Baoyu Zhao
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Fenglei Du
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Marlène Rio
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, 75015 Paris, France; Service de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Jeanne Amiel
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, 75015 Paris, France; Service de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Archa H Fox
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia; School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia; The Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Lucie Etienne
- CIRI-International Center for Infectiology Research, Inserm U1111, CNRS UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Univ Lyon, 69007 Lyon, France
| | - Charles S Bond
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Laurence Colleaux
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, 75015 Paris, France; Service de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Nicolas Manel
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France.
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113
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Fokkema J, Fermie J, Liv N, van den Heuvel DJ, Konings TOM, Blab GA, Meijerink A, Klumperman J, Gerritsen HC. Fluorescently Labelled Silica Coated Gold Nanoparticles as Fiducial Markers for Correlative Light and Electron Microscopy. Sci Rep 2018; 8:13625. [PMID: 30206379 PMCID: PMC6133918 DOI: 10.1038/s41598-018-31836-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/22/2018] [Indexed: 11/09/2022] Open
Abstract
In this work, gold nanoparticles coated with a fluorescently labelled (rhodamine B) silica shell are presented as fiducial markers for correlative light and electron microscopy (CLEM). The synthesis of the particles is optimized to obtain homogeneous, spherical core-shell particles of arbitrary size. Next, particles labelled with different fluorophore densities are characterized to determine under which conditions bright and (photo)stable particles can be obtained. 2 and 3D CLEM examples are presented where optimized particles are used for correlation. In the 2D example, fiducials are added to a cryosection of cells whereas in the 3D example cells are imaged after endocytosis of the fiducials. Both examples demonstrate that the particles are clearly visible in both modalities and can be used for correlation. Additionally, the recognizable core-shell structure of the fiducials proves to be very powerful in electron microscopy: it makes it possible to irrefutably identify the particles and makes it easy to accurately determine the center of the fiducials.
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Affiliation(s)
- Jantina Fokkema
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Job Fermie
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Nalan Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dave J van den Heuvel
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Tom O M Konings
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Gerhard A Blab
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Andries Meijerink
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Hans C Gerritsen
- Soft Condensed Matter and Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
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114
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Möbius W, Posthuma G. Sugar and ice: Immunoelectron microscopy using cryosections according to the Tokuyasu method. Tissue Cell 2018; 57:90-102. [PMID: 30201442 DOI: 10.1016/j.tice.2018.08.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/26/2018] [Accepted: 08/22/2018] [Indexed: 11/29/2022]
Abstract
Since the pioneering work of Kiyoteru Tokuyasu in the 70ths the use of thawed cryosections prepared according to the "Tokuyasu-method" for immunoelectron microscopy did not lose popularity. We owe this method a whole subcellular world described by discrete gold particles pointing at cargo, receptors and organelle markers on delicate images of the inner life of a cell. Here we explain the procedure of sample preparation, sectioning and immunolabeling in view of recent developments and the reasoning behind protocols including some historical perspective. Cryosections are prepared from chemically fixed and sucrose infiltrated samples and labeled with affinity probes and electron dense markers. These sections are ideal substrates for immunolabeling, since antigens are not exposed to organic solvent dehydration or masked by resin. Instead, the structures remain fully hydrated throughout the labeling procedure. Furthermore, target molecules inside dense intercellular structural elements, cells and organelles are accessible to antibodies from the section surface. For the validation of antibody specificity several approaches are recommended including knock-out tissue and reagent controls. Correlative light and electron microscopy strategies involving correlative probes are possible as well as correlation of live imaging with the underlying ultrastructure. By applying stereology, gold labeling can be quantified and evaluated for specificity.
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Affiliation(s)
- Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany.
| | - George Posthuma
- Department of Cell Biology, Cell Microscopy Core, University Medical Center Utrecht, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
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115
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Muskelin Coordinates PrP C Lysosome versus Exosome Targeting and Impacts Prion Disease Progression. Neuron 2018; 99:1155-1169.e9. [PMID: 30174115 DOI: 10.1016/j.neuron.2018.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/04/2018] [Accepted: 08/06/2018] [Indexed: 01/01/2023]
Abstract
Cellular prion protein (PrPC) modulates cell adhesion and signaling in the brain. Conversion to its infectious isoform causes neurodegeneration, including Creutzfeldt-Jakob disease in humans. PrPC undergoes rapid plasma membrane turnover and extracellular release via exosomes. However, the intracellular transport of PrPC and its potential impact on prion disease progression is barely understood. Here we identify critical components of PrPC trafficking that also link intracellular and extracellular PrPC turnover. PrPC associates with muskelin, dynein, and KIF5C at transport vesicles. Notably, muskelin coordinates bidirectional PrPC transport and facilitates lysosomal degradation over exosomal PrPC release. Muskelin gene knockout consequently causes PrPC accumulation at the neuronal surface and on secreted exosomes. Moreover, prion disease onset is accelerated following injection of pathogenic prions into muskelin knockout mice. Our data identify an essential checkpoint in PrPC turnover. They propose a novel connection between neuronal intracellular lysosome targeting and extracellular exosome trafficking, relevant to the pathogenesis of neurodegenerative conditions.
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116
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Direct imaging of uncoated biological samples enables correlation of super-resolution and electron microscopy data. Sci Rep 2018; 8:11610. [PMID: 30072703 PMCID: PMC6072772 DOI: 10.1038/s41598-018-29970-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/23/2018] [Indexed: 11/08/2022] Open
Abstract
A simple method for imaging biological tissue samples by electron microscopy and its correlation with super-resolution light microscopy is presented. This room temperature protocol, based on protecting thin biological specimens with methylcellulose and imaging with low voltage scanning electron microscopy, circumvents complex classical electron microscopy sample preparation steps requiring dehydration, resin embedding and use of contrast agents. This technique facilitates visualization of subcellular structures e.g. synaptic clefts and synaptic vesicles in mouse brain tissue and the organization of mitochondrial cristae in the zebrafish retina. Application of immunogold protocols to these samples can determine the precise localization of synaptic proteins and, in combination with super-resolution light microscopy methods clearly pinpoints the subcellular distribution of several proteins in the tissue. The simplicity of the method, including section collection on a silicon wafer, reduces artefacts and correlates protein location with sample morphology.
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117
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Bertolin G, Bulteau AL, Alves-Guerra MC, Burel A, Lavault MT, Gavard O, Le Bras S, Gagné JP, Poirier GG, Le Borgne R, Prigent C, Tramier M. Aurora kinase A localises to mitochondria to control organelle dynamics and energy production. eLife 2018; 7:38111. [PMID: 30070631 PMCID: PMC6140714 DOI: 10.7554/elife.38111] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/01/2018] [Indexed: 12/18/2022] Open
Abstract
Many epithelial cancers show cell cycle dysfunction tightly correlated with the overexpression of the serine/threonine kinase Aurora A (AURKA). Its role in mitotic progression has been extensively characterised, and evidence for new AURKA functions emerges. Here, we reveal that AURKA is located and imported in mitochondria in several human cancer cell lines. Mitochondrial AURKA impacts on two organelle functions: mitochondrial dynamics and energy production. When AURKA is expressed at endogenous levels during interphase, it induces mitochondrial fragmentation independently from RALA. Conversely, AURKA enhances mitochondrial fusion and ATP production when it is over-expressed. We demonstrate that AURKA directly regulates mitochondrial functions and that AURKA over-expression promotes metabolic reprogramming by increasing mitochondrial interconnectivity. Our work paves the way to anti-cancer therapeutics based on the simultaneous targeting of mitochondrial functions and AURKA inhibition. Structures called mitochondria power cells by turning oxygen and sugar into chemical energy. Each cell can have thousands of mitochondria, which work together to supply changing energy demands. They can fuse together or break apart, forming networks that change size and produce different amounts of energy. Getting the balance right is crucial; if energy levels are too low, the cell will not be able to grow and divide. If energy levels are too high, the cell can grow at a faster rate, which can contribute to the cell becoming cancerous. Although we know that mitochondria provide energy, it is not clear how they communicate to fine-tune the supply. Some clues come from cancer cells that seem dependent on their mitochondria for survival. In these cells, levels of a protein called AURKA are higher than normal. AURKA helps cells to divide, and it interacts with many different proteins. This complexity makes it difficult to work out exactly what AURKA does, but it is possible that it plays a role in energy supply. Bertolin et al. have now investigated whether mitochondria use AURKA to communicate inside human breast cancer cells. Tagging AURKA proteins with a fluorescent marker revealed that it accumulates inside mitochondria. Once it gets there, AURKA changes the shape of the mitochondria, which has dramatic effects on their capacity to produce energy. At normal levels, AURKA causes the mitochondria to fragment, breaking apart into smaller pieces. This maintains their energy output at a normal level. If AURKA levels are too high, the mitochondria fuse together and produce more energy. This means AURKA could help to fuel fast-growing cancer cells. Current drugs that aim to treat cancer by blocking the activity of AURKA show poor results. This is partly due to the fact that the protein has so many different roles in the cell. Finding that AURKA affects mitochondria is the first step in understanding one of its unknown roles. It also suggests the possibility of developing new drugs to change how mitochondria make energy in cancer cells that contain high levels of AURKA.
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Affiliation(s)
- Giulia Bertolin
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France
| | - Anne-Laure Bulteau
- ENS de Lyon, Lyon, France.,CNRS UMR 5242, Lyon, France.,INRA USC 1370, Lyon, France
| | - Marie-Clotilde Alves-Guerra
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR 8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Agnes Burel
- Microscopy Rennes Imaging Centre, SFR Biosit, UMS CNRS 3480- US INSERM 018, Université de Rennes, Rennes, France
| | - Marie-Thérèse Lavault
- Microscopy Rennes Imaging Centre, SFR Biosit, UMS CNRS 3480- US INSERM 018, Université de Rennes, Rennes, France
| | - Olivia Gavard
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France.,Equipes labélisées Ligue Contre Le Cancer, Rennes, France.,Centre de recherche du CHU de Québec, Faculté de Médecine, Université Laval, Québec, Canada
| | - Stephanie Le Bras
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France
| | - Jean-Philippe Gagné
- Centre de recherche du CHU de Québec, Faculté de Médecine, Université Laval, Québec, Canada
| | - Guy G Poirier
- Centre de recherche du CHU de Québec, Faculté de Médecine, Université Laval, Québec, Canada
| | - Roland Le Borgne
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France.,Equipes labélisées Ligue Contre Le Cancer, Rennes, France
| | - Claude Prigent
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France.,Equipes labélisées Ligue Contre Le Cancer, Rennes, France
| | - Marc Tramier
- CNRS, UMR 6290, Rennes, France.,Université de Rennes 1, UBL, Genetics and Development Institute of Rennes (IGDR), Rennes, France.,Microscopy Rennes Imaging Centre, SFR Biosit, UMS CNRS 3480- US INSERM 018, Université de Rennes, Rennes, France
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118
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Mauthe M, Orhon I, Rocchi C, Zhou X, Luhr M, Hijlkema KJ, Coppes RP, Engedal N, Mari M, Reggiori F. Chloroquine inhibits autophagic flux by decreasing autophagosome-lysosome fusion. Autophagy 2018; 14:1435-1455. [PMID: 29940786 PMCID: PMC6103682 DOI: 10.1080/15548627.2018.1474314] [Citation(s) in RCA: 1246] [Impact Index Per Article: 207.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 02/08/2023] Open
Abstract
Macroautophagy/autophagy is a conserved transport pathway where targeted structures are sequestered by phagophores, which mature into autophagosomes, and then delivered into lysosomes for degradation. Autophagy is involved in the pathophysiology of numerous diseases and its modulation is beneficial for the outcome of numerous specific diseases. Several lysosomal inhibitors such as bafilomycin A1 (BafA1), protease inhibitors and chloroquine (CQ), have been used interchangeably to block autophagy in in vitro experiments assuming that they all primarily block lysosomal degradation. Among them, only CQ and its derivate hydroxychloroquine (HCQ) are FDA-approved drugs and are thus currently the principal compounds used in clinical trials aimed to treat tumors through autophagy inhibition. However, the precise mechanism of how CQ blocks autophagy remains to be firmly demonstrated. In this study, we focus on how CQ inhibits autophagy and directly compare its effects to those of BafA1. We show that CQ mainly inhibits autophagy by impairing autophagosome fusion with lysosomes rather than by affecting the acidity and/or degradative activity of this organelle. Furthermore, CQ induces an autophagy-independent severe disorganization of the Golgi and endo-lysosomal systems, which might contribute to the fusion impairment. Strikingly, HCQ-treated mice also show a Golgi disorganization in kidney and intestinal tissues. Altogether, our data reveal that CQ and HCQ are not bona fide surrogates for other types of late stage lysosomal inhibitors for in vivo experiments. Moreover, the multiple cellular alterations caused by CQ and HCQ call for caution when interpreting results obtained by blocking autophagy with this drug.
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Affiliation(s)
- Mario Mauthe
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
| | - Idil Orhon
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Cecilia Rocchi
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Xingdong Zhou
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Morten Luhr
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Oslo, Norway
| | - Kerst-Jan Hijlkema
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert P. Coppes
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nikolai Engedal
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Oslo, Norway
| | - Muriel Mari
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
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119
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Santos MF, Rappa G, Karbanová J, Kurth T, Corbeil D, Lorico A. VAMP-associated protein-A and oxysterol-binding protein-related protein 3 promote the entry of late endosomes into the nucleoplasmic reticulum. J Biol Chem 2018; 293:13834-13848. [PMID: 30018135 DOI: 10.1074/jbc.ra118.003725] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/13/2018] [Indexed: 12/13/2022] Open
Abstract
The endocytic pathway plays an instrumental role in recycling internalized molecules back to the plasma membrane or in directing them to lysosomes for degradation. We recently reported a new role of endosomes-the delivery of components from extracellular vesicles (EVs) to the nucleoplasm of recipient cells. Using indirect immunofluorescence, FRET, immunoisolation techniques, and RNAi, we report here a tripartite protein complex (referred to as the VOR complex) that is essential for the nuclear transfer of EV-derived components by orchestrating the specific localization of late endosomes into nucleoplasmic reticulum. We found that the VOR complex contains the endoplasmic reticulum-localized vesicle-associated membrane protein (VAMP)-associated protein A (VAP-A), the cytoplasmic oxysterol-binding protein-related protein 3 (ORP3), and late endosome-associated small GTPase Rab7. The silencing of VAP-A or ORP3 abrogated the association of Rab7-positive late endosomes with nuclear envelope invaginations and, hence, the transport of endocytosed EV-derived components to the nucleoplasm of recipient cells. We conclude that the VOR complex can be targeted to inhibit EV-mediated intercellular communication, which can have therapeutic potential for managing cancer in which the release of EVs is dysregulated.
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Affiliation(s)
- Mark F Santos
- From the Roseman Cancer Center and Department of Pathology, Roseman University College of Medicine, Las Vegas, Nevada 89135
| | - Germana Rappa
- From the Roseman Cancer Center and Department of Pathology, Roseman University College of Medicine, Las Vegas, Nevada 89135
| | | | - Thomas Kurth
- the Biotechnology Center and.,DFG-Center for Regenerative Therapies, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany, and
| | - Denis Corbeil
- From the Roseman Cancer Center and Department of Pathology, Roseman University College of Medicine, Las Vegas, Nevada 89135, .,the Biotechnology Center and.,DFG-Center for Regenerative Therapies, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany, and
| | - Aurelio Lorico
- From the Roseman Cancer Center and Department of Pathology, Roseman University College of Medicine, Las Vegas, Nevada 89135, .,the Mediterranean Institute of Oncology Foundation, Via Penninazzo 11, 95029 Viagrande, Italy
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120
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Detection of mRNA and Associated Molecules by ISH-IEM on Frozen Sections. Methods Mol Biol 2018. [PMID: 29130197 DOI: 10.1007/978-1-4939-7213-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The use of tagged RNA probes to directly hybridize frozen sections of chemically fixed tissues, followed by the tag detection with specific antibodies and gold conjugates form the core of the in situ hybridization (ISH)-immunoelectron microscopy (IEM) method that we have developed and successfully used to detect endogenous gurken and bicoid mRNAs in Drosophila oocytes.
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121
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Abstract
Wnt/β-catenin signaling is crucial for adult homeostasis and stem cell maintenance, and its dysregulation is strongly associated to cancer. Upon Wnt binding, Wnt receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The assembly and regulation of these signalosomes remains largely elusive. Here, we use internally tagged Wnt ligands as a tool to isolate and analyze the composition and regulation of endogenous Wnt receptor complexes. We identify a positive regulator of Wnt signaling that facilitates signalosome formation by promoting intramembrane receptor interactions. Our results reveal that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps and involves regulated intramembrane interactions. Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt–FZD assemblies via intramembrane interactions. Subsequently, these Wnt–FZD–TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions.
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122
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Jonker CTH, Galmes R, Veenendaal T, Ten Brink C, van der Welle REN, Liv N, de Rooij J, Peden AA, van der Sluijs P, Margadant C, Klumperman J. Vps3 and Vps8 control integrin trafficking from early to recycling endosomes and regulate integrin-dependent functions. Nat Commun 2018; 9:792. [PMID: 29476049 PMCID: PMC5824891 DOI: 10.1038/s41467-018-03226-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/30/2018] [Indexed: 01/09/2023] Open
Abstract
Recycling endosomes maintain plasma membrane homeostasis and are important for cell polarity, migration, and cytokinesis. Yet, the molecular machineries that drive endocytic recycling remain largely unclear. The CORVET complex is a multi-subunit tether required for fusion between early endosomes. Here we show that the CORVET-specific subunits Vps3 and Vps8 also regulate vesicular transport from early to recycling endosomes. Vps3 and Vps8 localise to Rab4-positive recycling vesicles and co-localise with the CHEVI complex on Rab11-positive recycling endosomes. Depletion of Vps3 or Vps8 does not affect transferrin recycling, but delays the delivery of internalised integrins to recycling endosomes and their subsequent return to the plasma membrane. Consequently, Vps3/8 depletion results in defects in integrin-dependent cell adhesion and spreading, focal adhesion formation, and cell migration. These data reveal a role for Vps3 and Vps8 in a specialised recycling pathway important for integrin trafficking.
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Affiliation(s)
- C T H Jonker
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,Department of Ophthalmology, Weill Cornell Medicine, 1300 York Ave, New York, NY, 10065, USA
| | - R Galmes
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - T Veenendaal
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - C Ten Brink
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - R E N van der Welle
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - N Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - J de Rooij
- Section Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht Universty, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - A A Peden
- Department of Biomedical Science, The University of Sheffield, Sheffield, S10 2TN, UK
| | - P van der Sluijs
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584, CH Utrecht, The Netherlands
| | - C Margadant
- Department of Molecular Cell Biology, Sanquin Research, Plesmanlaan 125, 1066 CX, Amsterdam, The Netherlands
| | - J Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
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123
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McArthur K, Whitehead LW, Heddleston JM, Li L, Padman BS, Oorschot V, Geoghegan ND, Chappaz S, Davidson S, San Chin H, Lane RM, Dramicanin M, Saunders TL, Sugiana C, Lessene R, Osellame LD, Chew TL, Dewson G, Lazarou M, Ramm G, Lessene G, Ryan MT, Rogers KL, van Delft MF, Kile BT. BAK/BAX macropores facilitate mitochondrial herniation and mtDNA efflux during apoptosis. Science 2018; 359:359/6378/eaao6047. [DOI: 10.1126/science.aao6047] [Citation(s) in RCA: 376] [Impact Index Per Article: 62.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/20/2017] [Accepted: 01/24/2018] [Indexed: 12/17/2022]
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124
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Willemen HLDM, Kavelaars A, Prado J, Maas M, Versteeg S, Nellissen LJJ, Tromp J, Gonzalez Cano R, Zhou W, Jakobsson ME, Małecki J, Posthuma G, Habib AM, Heijnen CJ, Falnes PØ, Eijkelkamp N. Identification of FAM173B as a protein methyltransferase promoting chronic pain. PLoS Biol 2018; 16:e2003452. [PMID: 29444090 PMCID: PMC5828452 DOI: 10.1371/journal.pbio.2003452] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 02/27/2018] [Accepted: 01/24/2018] [Indexed: 12/31/2022] Open
Abstract
Chronic pain is a debilitating problem, and insights in the neurobiology of chronic pain are needed for the development of novel pain therapies. A genome-wide association study implicated the 5p15.2 region in chronic widespread pain. This region includes the coding region for FAM173B, a functionally uncharacterized protein. We demonstrate here that FAM173B is a mitochondrial lysine methyltransferase that promotes chronic pain. Knockdown and sensory neuron overexpression strategies showed that FAM173B is involved in persistent inflammatory and neuropathic pain via a pathway dependent on its methyltransferase activity. FAM173B methyltransferase activity in sensory neurons hyperpolarized mitochondria and promoted macrophage/microglia activation through a reactive oxygen species–dependent pathway. In summary, we uncover a role for methyltransferase activity of FAM173B in the neurobiology of pain. These results also highlight FAM173B methyltransferase activity as a potential therapeutic target to treat debilitating chronic pain conditions. Pain is an evolutionarily conserved physiological phenomenon necessary for survival. Yet, pain can become pathological when it occurs independently of noxious stimuli. The molecular mechanisms of pathological pain are still poorly understood, limiting the development of highly needed novel analgesics. Recently, genetic variations in the genomic region encoding FAM173B—a functionally uncharacterized protein—have been linked to chronic pain in humans. In this study, we identify the role and function of FAM173B in the development of pathological pain. We used genetic, biochemical, and behavioral approaches in mice to show that FAM173B is a mitochondrial lysine methyltransferase—a protein that transfers methyl group to donor proteins. By genetically silencing or overexpressing FAM173B in sensory neurons, we showed that FAM173B methyltransferase activity promotes the development of chronic pain. In addition, we discovered that FAM173B methyltransferase activity in the mitochondria of sensory neurons promotes chronic pain via a pathway that depends on the production of reactive oxygen species and on the engagement of spinal cord microglia—engulfing cells of the central nervous system. These data point to an essential role of FAM173B in the regulation of pathological pain.
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Affiliation(s)
- Hanneke L. D. M. Willemen
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Annemieke Kavelaars
- Laboratory of Neuroimmunology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Judith Prado
- Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Mirjam Maas
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Sabine Versteeg
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Lara J. J. Nellissen
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Jeshua Tromp
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Rafael Gonzalez Cano
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
- Department of Pharmacology and Institute of Neuroscience, University of Granada, Granada, Spain
| | - Wenjun Zhou
- Laboratory of Neuroimmunology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Magnus E. Jakobsson
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Jędrzej Małecki
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - George Posthuma
- Department of Cell Biology and Institute of Biomembranes, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Abdella M. Habib
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
- College of Medicine, Member of Qatar Health, Qatar University, Doha, Qatar
| | - Cobi J. Heijnen
- Laboratory of Neuroimmunology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Pål Ø. Falnes
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Niels Eijkelkamp
- Laboratory of Neuroimmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
- Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
- * E-mail:
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125
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Gosavi P, Houghton FJ, McMillan PJ, Hanssen E, Gleeson PA. The Golgi ribbon in mammalian cells negatively regulates autophagy by modulating mTOR activity. J Cell Sci 2018; 131:jcs.211987. [PMID: 29361552 DOI: 10.1242/jcs.211987] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/20/2017] [Indexed: 12/25/2022] Open
Abstract
In vertebrates, individual Golgi stacks are joined into a compact ribbon structure; however, the relevance of a ribbon structure has been elusive. Here, we exploit the finding that the membrane tether of the trans-Golgi network, GCC88 (encoded by GCC1), regulates the balance between Golgi mini-stacks and the Golgi ribbon. Loss of Golgi ribbons in stable cells overexpressing GCC88 resulted in compromised mechanistic target of rapamycin (mTOR) signaling and a dramatic increase in LC3-II-positive autophagosomes, whereas RNAi-mediated depletion of GCC88 restored the Golgi ribbon and reduced autophagy. mTOR was absent from dispersed Golgi mini-stacks whereas recruitment of mTOR to lysosomes was unaffected. We show that the Golgi ribbon is a site for localization and activation of mTOR, a process dependent on the ribbon structure. We demonstrate a strict temporal sequence of fragmentation of Golgi ribbon, loss of Golgi mTOR and subsequent increased autophagy. Golgi ribbon fragmentation has been reported in various neurodegenerative diseases and we demonstrate the potential relevance of our findings in neuronal cells using a model of neurodegeneration. Overall, this study highlights a role for the Golgi ribbon in pathways central to cellular homeostasis.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Prajakta Gosavi
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Fiona J Houghton
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul J McMillan
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia.,Biological Optical Microscopy Platform, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Eric Hanssen
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia.,Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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126
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Wang X, Li F, Xie L, Crane J, Zhen G, Mishina Y, Deng R, Gao B, Chen H, Liu S, Yang P, Gao M, Tu M, Wang Y, Wan M, Fan C, Cao X. Inhibition of overactive TGF-β attenuates progression of heterotopic ossification in mice. Nat Commun 2018; 9:551. [PMID: 29416028 PMCID: PMC5803194 DOI: 10.1038/s41467-018-02988-5] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 01/11/2018] [Indexed: 12/24/2022] Open
Abstract
Acquired heterotopic ossification (HO) is a painful and debilitating disease characterized by extraskeletal bone formation after injury. The exact pathogenesis of HO remains unknown. Here we show that TGF-β initiates and promotes HO in mice. We find that calcified cartilage and newly formed bone resorb osteoclasts after onset of HO, which leads to high levels of active TGF-β that recruit mesenchymal stromal/progenitor cells (MSPCs) in the HO microenvironment. Transgenic expression of active TGF-β in tendon induces spontaneous HO, whereas systemic injection of a TGF-β neutralizing antibody attenuates ectopic bone formation in traumatic and BMP-induced mouse HO models, and in a fibrodysplasia ossificans progressive mouse model. Moreover, inducible knockout of the TGF-β type II receptor in MSPCs inhibits HO progression in HO mouse models. Our study points toward elevated levels of active TGF-β as inducers and promoters of ectopic bone formation, and suggest that TGF-β might be a therapeutic target in HO.
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MESH Headings
- Achilles Tendon/drug effects
- Achilles Tendon/injuries
- Adult
- Animals
- Antibodies, Neutralizing/pharmacology
- Becaplermin/metabolism
- Bone Remodeling
- Brain Injuries, Traumatic
- Cartilage
- Case-Control Studies
- Disease Models, Animal
- Elbow Joint/surgery
- Female
- Fracture Fixation, Internal
- Fractures, Bone
- Humans
- Male
- Mesenchymal Stem Cells/metabolism
- Mice
- Mice, Knockout
- Mice, Transgenic
- Middle Aged
- Muscle, Skeletal/pathology
- Myositis Ossificans/metabolism
- Ossification, Heterotopic/metabolism
- Osteoclasts
- Osteogenesis/drug effects
- Receptor, Transforming Growth Factor-beta Type II/genetics
- Spinal Cord Injuries
- Tendon Injuries
- Tendons
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/metabolism
- Transforming Growth Factor beta1/metabolism
- Young Adult
- Elbow Injuries
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Affiliation(s)
- Xiao Wang
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Fengfeng Li
- Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, 200030, Shanghai, China
| | - Liang Xie
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Janet Crane
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Gehua Zhen
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yuji Mishina
- School of Dentistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ruoxian Deng
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Bo Gao
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Hao Chen
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Shen Liu
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, 200030, Shanghai, China
| | - Ping Yang
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Manman Gao
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Manli Tu
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yiguo Wang
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Mei Wan
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Cunyi Fan
- Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, 200030, Shanghai, China
| | - Xu Cao
- Department of Orthopedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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127
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Gonzalez AC, Schweizer M, Jagdmann S, Bernreuther C, Reinheckel T, Saftig P, Damme M. Unconventional Trafficking of Mammalian Phospholipase D3 to Lysosomes. Cell Rep 2018; 22:1040-1053. [PMID: 29386126 DOI: 10.1016/j.celrep.2017.12.100] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/10/2017] [Accepted: 12/26/2017] [Indexed: 01/08/2023] Open
Abstract
Variants in the phospholipase D3 (PLD3) gene have genetically been linked to late-onset Alzheimer's disease. We present a detailed biochemical analysis of PLD3 and reveal its endogenous localization in endosomes and lysosomes. PLD3 reaches lysosomes as a type II transmembrane protein via a (for mammalian cells) uncommon intracellular biosynthetic route that depends on the ESCRT (endosomal sorting complex required for transport) machinery. PLD3 is sorted into intraluminal vesicles of multivesicular endosomes, and ESCRT-dependent sorting correlates with ubiquitination. In multivesicular endosomes, PLD3 is subjected to proteolytic cleavage, yielding a stable glycosylated luminal polypeptide and a rapidly degraded N-terminal membrane-bound fragment. This pathway closely resembles the delivery route of carboxypeptidase S to the yeast vacuole. Our experiments reveal a biosynthetic route of PLD3 involving proteolytic processing and ESCRT-dependent sorting for its delivery to lysosomes in mammalian cells.
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Affiliation(s)
| | - Michaela Schweizer
- Center of Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - Sebastian Jagdmann
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany
| | - Christian Bernreuther
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Reinheckel
- Institute of Molecular Medicine and Cell Research, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany
| | - Markus Damme
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany.
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128
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Caldieri G, Barbieri E, Nappo G, Raimondi A, Bonora M, Conte A, Verhoef LGGC, Confalonieri S, Malabarba MG, Bianchi F, Cuomo A, Bonaldi T, Martini E, Mazza D, Pinton P, Tacchetti C, Polo S, Di Fiore PP, Sigismund S. Reticulon 3-dependent ER-PM contact sites control EGFR nonclathrin endocytosis. Science 2018; 356:617-624. [PMID: 28495747 DOI: 10.1126/science.aah6152] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 02/21/2017] [Accepted: 03/24/2017] [Indexed: 11/02/2022]
Abstract
The integration of endocytic routes is critical to regulate receptor signaling. A nonclathrin endocytic (NCE) pathway of the epidermal growth factor receptor (EGFR) is activated at high ligand concentrations and targets receptors to degradation, attenuating signaling. Here we performed an unbiased molecular characterization of EGFR-NCE. We identified NCE-specific regulators, including the endoplasmic reticulum (ER)-resident protein reticulon 3 (RTN3) and a specific cargo, CD147. RTN3 was critical for EGFR/CD147-NCE, promoting the creation of plasma membrane (PM)-ER contact sites that were required for the formation and/or maturation of NCE invaginations. Ca2+ release at these sites, triggered by inositol 1,4,5-trisphosphate (IP3)-dependent activation of ER Ca2+ channels, was needed for the completion of EGFR internalization. Thus, we identified a mechanism of EGFR endocytosis that relies on ER-PM contact sites and local Ca2+ signaling.
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Affiliation(s)
- Giusi Caldieri
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Elisa Barbieri
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Gilda Nappo
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Andrea Raimondi
- Centro Imaging Sperimentale, Istituto Scientifico San Raffaele, Via Olgettina 52, 20132 Milan, Italy
| | - Massimo Bonora
- Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies Center, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Alexia Conte
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Lisette G G C Verhoef
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Stefano Confalonieri
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Maria Grazia Malabarba
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy.,Dipartimento di Oncologia ed Emato-Oncologia (DiPO)-Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy
| | - Fabrizio Bianchi
- Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy
| | - Alessandro Cuomo
- Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy
| | - Tiziana Bonaldi
- Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy
| | - Emanuele Martini
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy
| | - Davide Mazza
- Centro Imaging Sperimentale, Istituto Scientifico San Raffaele, Via Olgettina 52, 20132 Milan, Italy
| | - Paolo Pinton
- Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies Center, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Carlo Tacchetti
- Centro Imaging Sperimentale, Istituto Scientifico San Raffaele, Via Olgettina 52, 20132 Milan, Italy.,Dipartimento di Medicina Sperimentale, Università degli Studi di Genova, Genoa, Italy
| | - Simona Polo
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy.,Dipartimento di Oncologia ed Emato-Oncologia (DiPO)-Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy
| | - Pier Paolo Di Fiore
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy. .,Dipartimento di Oncologia ed Emato-Oncologia (DiPO)-Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy.,Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy
| | - Sara Sigismund
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy.
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129
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Cano-Garrido O, Garcia-Fruitós E, Villaverde A, Sánchez-Chardi A. Improving Biomaterials Imaging for Nanotechnology: Rapid Methods for Protein Localization at Ultrastructural Level. Biotechnol J 2018; 13:e1700388. [PMID: 29271611 DOI: 10.1002/biot.201700388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/07/2017] [Indexed: 11/06/2022]
Abstract
The preparation of biological samples for electron microscopy is material- and time-consuming because it is often based on long protocols that also may produce artifacts. Protein labeling for transmission electron microscopy (TEM) is such an example, taking several days. However, for protein-based nanotechnology, high resolution imaging techniques are unique and crucial tools for studying the spatial distribution of these molecules, either alone or as components of biomaterials. In this paper, we tested two new short methods of immunolocalization for TEM, and compared them with a standard protocol in qualitative and quantitative approaches by using four protein-based nanoparticles. We reported a significant increase of labeling per area of nanoparticle in both new methodologies (H = 19.811; p < 0.001) with all the model antigens tested: GFP (H = 22.115; p < 0.001), MMP-2 (H = 19.579; p < 0.001), MMP-9 (H = 7.567; p < 0.023), and IFN-γ (H = 62.110; p < 0.001). We also found that the most suitable protocol for labeling depends on the nanoparticle's tendency to aggregate. Moreover, the shorter methods reduce artifacts, time (by 30%), residues, and reagents hindering, losing, or altering antigens, and obtaining a significant increase of protein localization (of about 200%). Overall, this study makes a step forward in the development of optimized protocols for the nanoscale localization of peptides and proteins within new biomaterials.
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Affiliation(s)
- Olivia Cano-Garrido
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Elena Garcia-Fruitós
- Departament de Producció de Remugants, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Caldes de Montbui 08140, Spain
| | - Antonio Villaverde
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Alejandro Sánchez-Chardi
- Servei de Microscòpia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain
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130
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Preußer C, Hung LH, Schneider T, Schreiner S, Hardt M, Moebus A, Santoso S, Bindereif A. Selective release of circRNAs in platelet-derived extracellular vesicles. J Extracell Vesicles 2018; 7:1424473. [PMID: 29359036 PMCID: PMC5769804 DOI: 10.1080/20013078.2018.1424473] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 12/05/2017] [Indexed: 12/17/2022] Open
Abstract
Circular RNAs (circRNAs) are a novel class of noncoding RNAs present in all eukaryotic cells investigated so far and generated by a special mode of alternative splicing of pre-mRNAs. Thereby, single exons, or multiple adjacent and spliced exons, are released in a circular form. CircRNAs are cell-type specifically expressed, are unusually stable, and can be found in various body fluids such as blood and saliva. Here we analysed circRNAs and the corresponding linear splice isoforms from human platelets, where circRNAs are particularly abundant, compared with other hematopoietic cell types. In addition, we isolated extracellular vesicles from purified and in vitro activated human platelets, using density-gradient centrifugation, followed by RNA-seq analysis for circRNA detection. We could demonstrate that circRNAs are packaged and released within both types of vesicles (microvesicles and exosomes) derived from platelets. Interestingly, we observed a selective release of circRNAs into the vesicles, suggesting a specific sorting mechanism. In sum, circRNAs represent yet another class of extracellular RNAs that circulate in the body and may be involved in signalling pathways. Since platelets are essential for central physiological processes such as haemostasis, wound healing, inflammation and cancer metastasis, these findings should greatly extend the potential of circRNAs as prognostic and diagnostic biomarkers.
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Affiliation(s)
- Christian Preußer
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Lee-Hsueh Hung
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Tim Schneider
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Silke Schreiner
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Martin Hardt
- Biomedical Research Centre Seltersberg, Imaging Unit, Justus Liebig University of Giessen, Giessen, Germany
| | - Anna Moebus
- Biomedical Research Centre Seltersberg, Imaging Unit, Justus Liebig University of Giessen, Giessen, Germany
| | - Sentot Santoso
- Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University of Giessen, Giessen, Germany
| | - Albrecht Bindereif
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
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131
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Saarinen NVV, Laiho JE, Richardson SJ, Zeissler M, Stone VM, Marjomäki V, Kantoluoto T, Horwitz MS, Sioofy-Khojine A, Honkimaa A, Hankaniemi MM, Flodström-Tullberg M, Hyöty H, Hytönen VP, Laitinen OH. A novel rat CVB1-VP1 monoclonal antibody 3A6 detects a broad range of enteroviruses. Sci Rep 2018; 8:33. [PMID: 29311608 PMCID: PMC5758616 DOI: 10.1038/s41598-017-18495-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/12/2017] [Indexed: 11/09/2022] Open
Abstract
Enteroviruses (EVs) are common RNA viruses that cause diseases ranging from rash to paralytic poliomyelitis. For example, EV-A and EV-C viruses cause hand-foot and mouth disease and EV-B viruses cause encephalitis and myocarditis, which can result in severe morbidity and mortality. While new vaccines and treatments for EVs are under development, methods for studying and diagnosing EV infections are still limited and therefore new diagnostic tools are required. Our aim was to produce and characterize new antibodies that work in multiple applications and detect EVs in tissues and in vitro. Rats were immunized with Coxsackievirus B1 capsid protein VP1 and hybridomas were produced. Hybridoma clones were selected based on their reactivity in different immunoassays. The most promising clone, 3A6, was characterized and it performed well in multiple techniques including ELISA, immunoelectron microscopy, immunocyto- and histochemistry and in Western blotting, detecting EVs in infected cells and tissues. It recognized several EV-Bs and also the EV-C representative Poliovirus 3, making it a broad-spectrum EV specific antibody. The 3A6 rat monoclonal antibody can help to overcome some of the challenges faced with commonly used EV antibodies: it enables simultaneous use of mouse-derived antibodies in double staining and it is useful in murine models.
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Affiliation(s)
- Niila V V Saarinen
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Jutta E Laiho
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | | | | | - Virginia M Stone
- Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
| | - Varpu Marjomäki
- Department of Biological and Environmental Science/Nanoscience center, University of Jyväskylä, Jyväskylä, Finland
| | - Tino Kantoluoto
- Department of Biological and Environmental Science/Nanoscience center, University of Jyväskylä, Jyväskylä, Finland
| | - Marc S Horwitz
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | | | - Anni Honkimaa
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Minna M Hankaniemi
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | | | - Heikki Hyöty
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.,Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland
| | - Vesa P Hytönen
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.,Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland
| | - Olli H Laitinen
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.
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132
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Engberts KB, Seinen C, Geerts WJC, Heijnen HFG. Electron Tomography and Correlative Approaches in Platelet Studies. Methods Mol Biol 2018; 1812:55-79. [PMID: 30171572 DOI: 10.1007/978-1-4939-8585-2_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Blood platelets play a central role in the arrest of bleeding and the development of thrombosis. Unraveling the complex processes of platelet biogenesis from megakaryocytes, platelet adhesion, aggregation, and secretory responses are important topics in the field of hemostasis and thrombosis. Analysis of the ultrastructural changes that occur during these processes is essential for understanding the rapid membrane dynamics and has contributed substantially to our present knowledge of platelet formation and functioning. Recent developments in real-time imaging, correlative light and electron microscopy imaging (CLEM), and 3D (cryo) electron microscopy and tomography offer exciting opportunities to improve studies of the platelet adhesive responses and secretion at the ultrastructural level in a close to native environment. In this chapter we discuss and illustrate cryo preparation techniques (high-pressure freezing, vitrification), correlative LM and EM workflows, and 3D cryo-electron tomography that we apply in our current research projects.
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Affiliation(s)
- Kasia B Engberts
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Cor Seinen
- Laboratory of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willie J C Geerts
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Harry F G Heijnen
- Laboratory of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands. .,Department of Cell Biology, Cell Microscopy Core, University Medical Center Utrecht, Utrecht, The Netherlands.
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133
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Kuo CL, van Meel E, Kytidou K, Kallemeijn WW, Witte M, Overkleeft HS, Artola ME, Aerts JM. Activity-Based Probes for Glycosidases: Profiling and Other Applications. Methods Enzymol 2017; 598:217-235. [PMID: 29306436 DOI: 10.1016/bs.mie.2017.06.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glycosidases mediate the fragmentation of glycoconjugates in the body, including the vital recycling of endogenous molecules. Several inherited diseases in man concern deficiencies in lysosomal glycosidases degrading glycosphingolipids. Prominent is Gaucher disease caused by an impaired lysosomal β-glucosidase (glucocerebrosidase, GBA) and resulting in pathological lysosomal storage of glucosylceramide (glucocerebroside) in tissue macrophages. GBA is a retaining glucosidase with a characteristic glycosyl-enzyme intermediate formed during catalysis. Using the natural suicide inhibitor cyclophellitol as a lead, we developed mechanism-based irreversible inhibitors of GBA equipped with a fluorescent reporter. These reagents covalently link to the catalytic nucleophile residue of GBA and permit specific and sensitive visualization of active enzyme molecules. The amphiphilic activity-based probes (ABPs) allow in situ detection of active GBA in cells and organisms. Furthermore, they may be used to biochemically confirm the diagnosis of Gaucher disease and they might assist in screening for small compounds interacting with the catalytic pocket. While the focus of this chapter is ABPs for β-glucosidases and Gaucher disease, the described concept has meanwhile been extended to other retaining glycosidases and related disease conditions as well.
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Affiliation(s)
- Chi-Lin Kuo
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Eline van Meel
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Kassiani Kytidou
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | | | - Martin Witte
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | | | - Marta Elena Artola
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
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134
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Mateos JM, Barmettler G, Doehner J, Ojeda Naharros I, Guhl B, Neuhauss SCF, Kaech A, Bachmann-Gagescu R, Ziegler U. Correlative Super-resolution and Electron Microscopy to Resolve Protein Localization in Zebrafish Retina. J Vis Exp 2017. [PMID: 29155784 PMCID: PMC5755354 DOI: 10.3791/56113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We present a method to investigate the subcellular protein localization in the larval zebrafish retina by combining super-resolution light microscopy and scanning electron microscopy. The sub-diffraction limit resolution capabilities of super-resolution light microscopes allow improving the accuracy of the correlated data. Briefly, 110 nanometer thick cryo-sections are transferred to a silicon wafer and, after immunofluorescence staining, are imaged by super-resolution light microscopy. Subsequently, the sections are preserved in methylcellulose and platinum shadowed prior to imaging in a scanning electron microscope (SEM). The images from these two microscopy modalities are easily merged using tissue landmarks with open source software. Here we describe the adapted method for the larval zebrafish retina. However, this method is also applicable to other types of tissues and organisms. We demonstrate that the complementary information obtained by this correlation is able to resolve the expression of mitochondrial proteins in relation with the membranes and cristae of mitochondria as well as to other compartments of the cell.
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Affiliation(s)
- José M Mateos
- Center for Microscopy and Image Analysis, University of Zurich;
| | - Gery Barmettler
- Center for Microscopy and Image Analysis, University of Zurich
| | - Jana Doehner
- Center for Microscopy and Image Analysis, University of Zurich
| | | | - Bruno Guhl
- Center for Microscopy and Image Analysis, University of Zurich
| | | | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich
| | - Ruxandra Bachmann-Gagescu
- Institute for Molecular Life Sciences, University of Zurich; Institute for Medical Genetics, University of Zurich
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zurich
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135
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Schneider VAF, Coorens M, Tjeerdsma-van Bokhoven JLM, Posthuma G, van Dijk A, Veldhuizen EJA, Haagsman HP. Imaging the Antistaphylococcal Activity of CATH-2: Mechanism of Attack and Regulation of Inflammatory Response. mSphere 2017; 2:e00370-17. [PMID: 29104934 PMCID: PMC5663982 DOI: 10.1128/msphere.00370-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022] Open
Abstract
Chicken cathelicidin-2 (CATH-2) is a broad-spectrum antimicrobial host defense peptide (HDP) that may serve as a paradigm for the development of new antimicrobial agents. While previous studies have elucidated the mechanism by which CATH-2 kills Escherichia coli, its mode of action against Gram-positive bacteria remains to be determined. In this study, we explored the underlying antibacterial mechanism of CATH-2 against a methicillin-resistant strain of Staphylococcus aureus and the effect of CATH-2-mediated S. aureus killing on immune activation. Visualization of the antimicrobial activity of CATH-2 against S. aureus with live-imaging confocal microscopy demonstrated that CATH-2 directly binds the bacteria, which is followed by membrane permeabilization and cell shrinkage. Transmission electron microscopy (TEM) studies further showed that CATH-2 initiated pronounced morphological changes of the membrane (mesosome formation) and ribosomal structures (clustering) in a dose-dependent manner. Immunolabeling of these sections demonstrated that CATH-2 binds and passes the bacterial membrane at subminimal bactericidal concentrations (sub-MBCs). Furthermore, competition assays and isothermal titration calorimetry (ITC) analysis provided evidence that CATH-2 directly interacts with lipoteichoic acid and cardiolipin. Finally, stimulation of macrophages with S. aureus and CATH-2 showed that CATH-2 not only kills S. aureus but also has the potential to limit S. aureus-induced inflammation at or above the MBC. Taken together, it is concluded that at sub-MBCs, CATH-2 perturbs the bacterial membrane and subsequently enters the cell and binds intracellular S. aureus components, while at or above the MBC, CATH-2 causes disruption of membrane integrity and inhibits S. aureus-induced macrophage activation. IMPORTANCE Due to the high use of antibiotics in both human and veterinary settings, many bacteria have become resistant to those antibiotics that we so heavily rely on. Methicillin-resistant S. aureus (MRSA) is one of these difficult-to-treat resistant pathogens for which novel antimicrobial therapies will be required in the near future. One novel approach could be the utilization of naturally occurring antimicrobial peptides, such as chicken CATH-2, which have been show to act against a wide variety of bacteria. However, before these peptides can be used clinically, more knowledge of their functions and mechanisms of action is required. In this study, we used live imaging and electron microscopy to visualize in detail how CATH-2 kills S. aureus, and we investigated how CATH-2 affects immune activation by S. aureus. Together, these results give a better understanding of how CATH-2 kills S. aureus and what the potential immunological consequences of this killing can be.
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Affiliation(s)
- Viktoria A. F. Schneider
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Maarten Coorens
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Johanna L. M. Tjeerdsma-van Bokhoven
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - George Posthuma
- Department of Cell Biology, Cell Microscopy Core, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Albert van Dijk
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Edwin J. A. Veldhuizen
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Henk P. Haagsman
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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136
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Tsuji T, Fujimoto T. Freeze-fracture-etching Electron Microscopy for Facile Analysis of Yeast Ultrastructure. Bio Protoc 2017; 7:e2556. [PMID: 34541202 DOI: 10.21769/bioprotoc.2556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/01/2017] [Accepted: 09/03/2017] [Indexed: 11/02/2022] Open
Abstract
We describe a streamlined method that enables the quick observation of yeast ultrastructure by electron microscopy (EM). Yeast cells are high-pressure frozen, freeze-fractured to cut across the cytoplasm, and freeze-etched to sublimate ice in the cytosol and the organelle lumen. The cellular structures delineated by these procedures are coated by a thin layer of platinum and carbon deposited by vacuum evaporation, and this platinum-carbon layer, or replica, is observed by transmission EM. The method differs from the deep-etching of pre-extracted samples in that intact live cells are processed without any chemical treatment. Lipid droplets made of unetchable lipid esters are observed most prominently, but other organelles-the nucleus, endoplasmic reticulum, Golgi, vacuoles, mitochondria-and their mutual relationships can be analyzed readily. It is of note that the entire procedure, from quick-freezing to EM observation, can be performed within a day.
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Affiliation(s)
- Takuma Tsuji
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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137
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Zhou X, Cong Y, Veenendaal T, Klumperman J, Shi D, Mari M, Reggiori F. Ultrastructural Characterization of Membrane Rearrangements Induced by Porcine Epidemic Diarrhea Virus Infection. Viruses 2017; 9:v9090251. [PMID: 28872588 PMCID: PMC5618017 DOI: 10.3390/v9090251] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 08/28/2017] [Accepted: 08/31/2017] [Indexed: 02/06/2023] Open
Abstract
The porcine epidemic diarrhea virus (PEDV) is a coronavirus (CoV) belonging to the α-CoV genus and it causes high mortality in infected sucking piglets, resulting in substantial losses in the farming industry. CoV trigger a drastic reorganization of host cell membranes to promote their replication and egression, but a detailed description of the intracellular remodeling induced by PEDV is still missing. In this study, we examined qualitatively and quantitatively, using electron microscopy, the intracellular membrane reorganization induced by PEDV over the course of an infection. With our ultrastructural approach, we reveal that, as most of CoV, PEDV initially forms double-membrane vesicles (DMVs) and convoluted membranes (CMs), which probably serve as replication/transcription platforms. Interestingly, we also found that viral particles start to form almost simultaneously in both the endoplasmic reticulum and the large virion-containing vacuoles (LVCVs), which are compartments originating from the Golgi, confirming that α-CoV assemble indistinguishably in two different organelles of the secretory pathway. Moreover, PEDV virons appear to have an immature and a mature form, similar to another α-CoV the transmissible gastroenteritis coronavirus (TGEV). Altogether, our study underlies the similarities and differences between the lifecycle of α-CoV and that of viruses belonging to other CoV subfamilies.
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Affiliation(s)
- Xingdong Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China.
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Yingying Cong
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Tineke Veenendaal
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
| | - Judith Klumperman
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
| | - Dongfang Shi
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China.
| | - Muriel Mari
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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138
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Parkinson Sac Domain Mutation in Synaptojanin 1 Impairs Clathrin Uncoating at Synapses and Triggers Dystrophic Changes in Dopaminergic Axons. Neuron 2017; 93:882-896.e5. [PMID: 28231468 DOI: 10.1016/j.neuron.2017.01.019] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/22/2016] [Accepted: 01/20/2017] [Indexed: 01/10/2023]
Abstract
Synaptojanin 1 (SJ1) is a major presynaptic phosphatase that couples synaptic vesicle endocytosis to the dephosphorylation of PI(4,5)P2, a reaction needed for the shedding of endocytic factors from their membranes. While the role of SJ1's 5-phosphatase module in this process is well recognized, the contribution of its Sac phosphatase domain, whose preferred substrate is PI4P, remains unclear. Recently a homozygous mutation in its Sac domain was identified in early-onset parkinsonism patients. We show that mice carrying this mutation developed neurological manifestations similar to those of human patients. Synapses of these mice displayed endocytic defects and a striking accumulation of clathrin-coated intermediates, strongly implicating Sac domain's activity in endocytic protein dynamics. Mutant brains had elevated auxilin (PARK19) and parkin (PARK2) levels. Moreover, dystrophic axonal terminal changes were selectively observed in dopaminergic axons in the dorsal striatum. These results strengthen evidence for a link between synaptic endocytic dysfunction and Parkinson's disease.
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139
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Fagernes CE, Stensløkken KO, Røhr ÅK, Berenbrink M, Ellefsen S, Nilsson GE. Extreme anoxia tolerance in crucian carp and goldfish through neofunctionalization of duplicated genes creating a new ethanol-producing pyruvate decarboxylase pathway. Sci Rep 2017; 7:7884. [PMID: 28801642 PMCID: PMC5554223 DOI: 10.1038/s41598-017-07385-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 06/23/2017] [Indexed: 11/09/2022] Open
Abstract
Without oxygen, most vertebrates die within minutes as they cannot meet cellular energy demands with anaerobic metabolism. However, fish of the genus Carassius (crucian carp and goldfish) have evolved a specialized metabolic system that allows them to survive prolonged periods without oxygen by producing ethanol as their metabolic end-product. Here we show that this has been made possible by the evolution of a pyruvate decarboxylase, analogous to that in brewer's yeast and the first described in vertebrates, in addition to a specialized alcohol dehydrogenase. Whole-genome duplication events have provided additional gene copies of the pyruvate dehydrogenase multienzyme complex that have evolved into a pyruvate decarboxylase, while other copies retained the essential function of the parent enzymes. We reveal the key molecular substitution in duplicated pyruvate dehydrogenase genes that underpins one of the most extreme hypoxic survival strategies among vertebrates and that is highly deleterious in humans.
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Affiliation(s)
| | - Kåre-Olav Stensløkken
- Institute of Basic Medical Sciences, University of Oslo, N-0372, Oslo, Norway.,Center for Heart Failure Research, University of Oslo, N-0317, Oslo, Norway
| | - Åsmund K Røhr
- Department of Biosciences, University of Oslo, N-0316, Oslo, Norway
| | - Michael Berenbrink
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Stian Ellefsen
- The Lillehammer Research Center for Medicine and Exercise Physiology, Inland Norway University of Applied Sciences, N-2604, Lillehammer, Norway
| | - Göran E Nilsson
- Department of Biosciences, University of Oslo, N-0316, Oslo, Norway.
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140
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Bacterial membrane vesicles transport their DNA cargo into host cells. Sci Rep 2017; 7:7072. [PMID: 28765539 PMCID: PMC5539193 DOI: 10.1038/s41598-017-07288-4] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 06/27/2017] [Indexed: 12/25/2022] Open
Abstract
Bacterial outer membrane vesicles (OMVs) are extracellular sacs containing biologically active products, such as proteins, cell wall components and toxins. OMVs are reported to contain DNA, however, little is known about the nature of this DNA, nor whether it can be transported into host cells. Our work demonstrates that chromosomal DNA is packaged into OMVs shed by bacteria during exponential phase. Most of this DNA was present on the external surfaces of OMVs, with smaller amounts located internally. The DNA within the internal compartments of Pseudomonas aeruginosa OMVs were consistently enriched in specific regions of the bacterial chromosome, encoding proteins involved in virulence, stress response, antibiotic resistance and metabolism. Furthermore, we demonstrated that OMVs carry DNA into eukaryotic cells, and this DNA was detectable by PCR in the nuclear fraction of cells. These findings suggest a role for OMV-associated DNA in bacterial-host cell interactions and have implications for OMV-based vaccines.
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141
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Three-Dimensional Imaging of Biological Tissue by Cryo X-Ray Ptychography. Sci Rep 2017; 7:6291. [PMID: 28740127 PMCID: PMC5524705 DOI: 10.1038/s41598-017-05587-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/31/2017] [Indexed: 12/16/2022] Open
Abstract
High-throughput three-dimensional cryogenic imaging of thick biological specimens is valuable for identifying biologically- or pathologically-relevant features of interest, especially for subsequent correlative studies. Unfortunately, high-resolution imaging techniques at cryogenic conditions often require sample reduction through sequential physical milling or sectioning for sufficient penetration to generate each image of the 3-D stack. This study represents the first demonstration of using ptychographic hard X-ray tomography at cryogenic temperatures for imaging thick biological tissue in a chemically-fixed, frozen-hydrated state without heavy metal staining and organic solvents. Applied to mammalian brain, this label-free cryogenic imaging method allows visualization of myelinated axons and sub-cellular features such as age-related pigmented cellular inclusions at a spatial resolution of ~100 nanometers and thicknesses approaching 100 microns. Because our approach does not require dehydration, staining or reduction of the sample, we introduce the possibility for subsequent analysis of the same tissue using orthogonal approaches that are expected to yield direct complementary insight to the biological features of interest.
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142
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Grumati P, Morozzi G, Hölper S, Mari M, Harwardt MLI, Yan R, Müller S, Reggiori F, Heilemann M, Dikic I. Full length RTN3 regulates turnover of tubular endoplasmic reticulum via selective autophagy. eLife 2017; 6. [PMID: 28617241 PMCID: PMC5517149 DOI: 10.7554/elife.25555] [Citation(s) in RCA: 294] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/14/2017] [Indexed: 12/21/2022] Open
Abstract
The turnover of endoplasmic reticulum (ER) ensures the correct biological activity of its distinct domains. In mammalian cells, the ER is degraded via a selective autophagy pathway (ER-phagy), mediated by two specific receptors: FAM134B, responsible for the turnover of ER sheets and SEC62 that regulates ER recovery following stress. Here, we identified reticulon 3 (RTN3) as a specific receptor for the degradation of ER tubules. Oligomerization of the long isoform of RTN3 is sufficient to trigger fragmentation of ER tubules. The long N-terminal region of RTN3 contains several newly identified LC3-interacting regions (LIR). Binding to LC3s/GABARAPs is essential for the fragmentation of ER tubules and their delivery to lysosomes. RTN3-mediated ER-phagy requires conventional autophagy components, but is independent of FAM134B. None of the other reticulon family members have the ability to induce fragmentation of ER tubules during starvation. Therefore, we assign a unique function to RTN3 during autophagy. DOI:http://dx.doi.org/10.7554/eLife.25555.001
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Affiliation(s)
- Paolo Grumati
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt, Germany
| | - Giulio Morozzi
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt, Germany
| | - Soraya Hölper
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt, Germany
| | - Muriel Mari
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Marie-Lena Ie Harwardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, United States
| | - Stefan Müller
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Ivan Dikic
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
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143
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BAP1 regulates IP3R3-mediated Ca 2+ flux to mitochondria suppressing cell transformation. Nature 2017; 546:549-553. [PMID: 28614305 PMCID: PMC5581194 DOI: 10.1038/nature22798] [Citation(s) in RCA: 282] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 04/28/2017] [Indexed: 12/18/2022]
Abstract
BRCA1-associated protein 1 (BAP1) is a potent tumor suppressor gene that modulates environmental carcinogenesis1-3. All carriers of inherited heterozygous germline BAP1 inactivating mutations (BAP1+/-) developed one and often several BAP1-/- malignancies in their lifetime4, mostly malignant mesothelioma (MM), uveal melanoma (UVM)2,5, etc6-10. Moreover, BAP1 acquired biallelic mutations are frequent in human cancers8,11-14. BAP1 tumor suppressor activity has been attributed to its nuclear localization where BAP1 helps maintaining genome integrity15-17. The possible activity of BAP1 in the cytoplasm was unknown. Cells with reduced levels of BAP1 exhibit chromosomal abnormalities and decreased DNA repair by homologous recombination18, indicating that BAP1 dosage is critical. Cells with extensive DNA damage should die and not grow into malignancies. We discovered that BAP1 localizes at the endoplasmic reticulum (ER). Here BAP1 binds, deubiquitylates and stabilizes type-3 inositol-1,4,5-trisphosphate-receptor (IP3R3), modulating calcium (Ca2+) release from the ER into the cytosol and mitochondria, promoting apoptosis. Reduced levels of BAP1 in BAP1+/- carriers caused reduction of both IP3R3 levels and Ca2+ flux, preventing BAP1+/- cells that had accumulated DNA damage from executing apoptosis. A higher fraction of cells exposed to either ionizing or ultraviolet radiation, or to asbestos, survived genotoxic stress resulting in a higher rate of cellular transformation. We propose that the high incidence of cancers in BAP1+/- carriers results from the combined reduced nuclear and cytoplasmic BAP1 activities. Our data provide a mechanistic rationale for the powerful ability of BAP1 to regulate gene-environment interaction.
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144
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Marion J, Le Bars R, Satiat-Jeunemaitre B, Boulogne C. Optimizing CLEM protocols for plants cells: GMA embedding and cryosections as alternatives for preservation of GFP fluorescence in Arabidopsis roots. J Struct Biol 2017; 198:196-202. [DOI: 10.1016/j.jsb.2017.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 03/23/2017] [Indexed: 12/21/2022]
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145
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Pyk2 modulates hippocampal excitatory synapses and contributes to cognitive deficits in a Huntington's disease model. Nat Commun 2017; 8:15592. [PMID: 28555636 PMCID: PMC5459995 DOI: 10.1038/ncomms15592] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 04/11/2017] [Indexed: 12/11/2022] Open
Abstract
The structure and function of spines and excitatory synapses are under the dynamic control of multiple signalling networks. Although tyrosine phosphorylation is involved, its regulation and importance are not well understood. Here we study the role of Pyk2, a non-receptor calcium-dependent protein-tyrosine kinase highly expressed in the hippocampus. Hippocampal-related learning and CA1 long-term potentiation are severely impaired in Pyk2-deficient mice and are associated with alterations in NMDA receptors, PSD-95 and dendritic spines. In cultured hippocampal neurons, Pyk2 has autophosphorylation-dependent and -independent roles in determining PSD-95 enrichment and spines density. Pyk2 levels are decreased in the hippocampus of individuals with Huntington and in the R6/1 mouse model of the disease. Normalizing Pyk2 levels in the hippocampus of R6/1 mice rescues memory deficits, spines pathology and PSD-95 localization. Our results reveal a role for Pyk2 in spine structure and synaptic function, and suggest that its deficit contributes to Huntington's disease cognitive impairments.
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146
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Nascimbeni AC, Giordano F, Dupont N, Grasso D, Vaccaro MI, Codogno P, Morel E. ER-plasma membrane contact sites contribute to autophagosome biogenesis by regulation of local PI3P synthesis. EMBO J 2017; 36:2018-2033. [PMID: 28550152 DOI: 10.15252/embj.201797006] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/21/2022] Open
Abstract
The double-membrane-bound autophagosome is formed by the closure of a structure called the phagophore, origin of which is still unclear. The endoplasmic reticulum (ER) is clearly implicated in autophagosome biogenesis due to the presence of the omegasome subdomain positive for DFCP1, a phosphatidyl-inositol-3-phosphate (PI3P) binding protein. Contribution of other membrane sources, like the plasma membrane (PM), is still difficult to integrate in a global picture. Here we show that ER-plasma membrane contact sites are mobilized for autophagosome biogenesis, by direct implication of the tethering extended synaptotagmins (E-Syts) proteins. Imaging data revealed that early autophagic markers are recruited to E-Syt-containing domains during autophagy and that inhibition of E-Syts expression leads to a reduction in autophagosome biogenesis. Furthermore, we demonstrate that E-Syts are essential for autophagy-associated PI3P synthesis at the cortical ER membrane via the recruitment of VMP1, the stabilizing ER partner of the PI3KC3 complex. These results highlight the contribution of ER-plasma membrane tethers to autophagosome biogenesis regulation and support the importance of membrane contact sites in autophagy.
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Affiliation(s)
- Anna Chiara Nascimbeni
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Francesca Giordano
- Institut Jacques Monod, CNRS UMR 7592, Paris, France.,Université Paris Diderot-Sorbonne Paris Cité, Paris, France
| | - Nicolas Dupont
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Daniel Grasso
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine, National Council for Scientific and Technological Research, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Maria I Vaccaro
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine, National Council for Scientific and Technological Research, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France .,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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147
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Schneppenheim J, Loock AC, Hüttl S, Schweizer M, Lüllmann-Rauch R, Oberg HH, Arnold P, Lehmann CHK, Dudziak D, Kabelitz D, Lucius R, Lennon-Duménil AM, Saftig P, Schröder B. The Influence of MHC Class II on B Cell Defects Induced by Invariant Chain/CD74 N-Terminal Fragments. THE JOURNAL OF IMMUNOLOGY 2017; 199:172-185. [DOI: 10.4049/jimmunol.1601533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 05/01/2017] [Indexed: 01/24/2023]
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148
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A novel immuno-gold labeling protocol for nanobody-based detection of HER2 in breast cancer cells using immuno-electron microscopy. J Struct Biol 2017; 199:1-11. [PMID: 28552722 DOI: 10.1016/j.jsb.2017.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 11/21/2022]
Abstract
Immuno-electron microscopy is commonly performed with the use of antibodies. In the last decade the antibody fragment indicated as nanobody (VHH or single domain antibody) has found its way to different applications previously done with conventional antibodies. Nanobodies can be selected to bind with high affinity and specificity to different antigens. They are small (molecular weight ca. 15kDa) and are usually easy to produce in microorganisms. Here we have evaluated the feasibility of a nanobody binding to HER2 for application in immuno-electron microscopy. To obtain highest labeling efficiency combined with optimal specificity, different labeling conditions were analysed, which included nanobody concentration, fixation and blocking conditions. The obtained optimal protocol was applied for post-embedment labeling of Tokuyasu cryosections and for pre-embedment labeling of HER2 for fluorescence microscopy and both transmission and scanning electron microscopy. We show that formaldehyde fixation after incubation with the anti-HER2 nanobody, improves labeling intensity. Among all tested blocking agents the best results were obtained with a mixture of cold water fish gelatine and acetylated bovine serum albumin, which prevented a-specific interactions causing background labeling while preserving specific interactions at the same time. In conclusion, we have developed a nanobody-based protocol for immuno-gold labeling of HER2 for Tokuyasu cryosections in TEM as well as for pre-embedment gold labeling of cells for both TEM and SEM.
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149
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VAN ELSLAND D, BOS E, PAWLAK J, OVERKLEEFT H, KOSTER A, VAN KASTEREN S. Correlative light and electron microscopy reveals discrepancy between gold and fluorescence labelling. J Microsc 2017; 267:309-317. [DOI: 10.1111/jmi.12567] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 02/17/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Affiliation(s)
- D.M. VAN ELSLAND
- Division of Bio-organic Synthesis, Leiden Institute of Chemistry, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
- Institute for Chemical Immunology, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
| | - E. BOS
- Department of Molecular Cell Biology, Section Electron Microscopy; Leiden University Medical Center; Leiden The Netherlands
| | - J.B. PAWLAK
- Division of Bio-organic Synthesis, Leiden Institute of Chemistry, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
- Institute for Chemical Immunology, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
| | - H.S. OVERKLEEFT
- Division of Bio-organic Synthesis, Leiden Institute of Chemistry, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
- Institute for Chemical Immunology, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
| | - A.J. KOSTER
- Department of Molecular Cell Biology, Section Electron Microscopy; Leiden University Medical Center; Leiden The Netherlands
| | - S.I. VAN KASTEREN
- Division of Bio-organic Synthesis, Leiden Institute of Chemistry, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
- Institute for Chemical Immunology, Gorlaeus Laboratories; Leiden University; Leiden The Netherlands
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150
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Mural lymphatic endothelial cells regulate meningeal angiogenesis in the zebrafish. Nat Neurosci 2017; 20:774-783. [PMID: 28459441 DOI: 10.1038/nn.4558] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 03/31/2017] [Indexed: 12/15/2022]
Abstract
Mural cells of the vertebrate brain maintain vascular integrity and function, play roles in stroke and are involved in maintenance of neural stem cells. However, the origins, diversity and roles of mural cells remain to be fully understood. Using transgenic zebrafish, we identified a population of isolated mural lymphatic endothelial cells surrounding meningeal blood vessels. These meningeal mural lymphatic endothelial cells (muLECs) express lymphatic endothelial cell markers and form by sprouting from blood vessels. In larvae, muLECs develop from a lymphatic endothelial loop in the midbrain into a dispersed, nonlumenized mural lineage. muLEC development requires normal signaling through the Vegfc-Vegfd-Ccbe1-Vegfr3 pathway. Mature muLECs produce vascular growth factors and accumulate low-density lipoproteins from the bloodstream. We find that muLECs are essential for normal meningeal vascularization. Together, these data identify an unexpected lymphatic lineage and developmental mechanism necessary for establishing normal meningeal blood vasculature.
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