1
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Dall'Armellina F, Stagi M, Swan LE. In silico modeling human VPS13 proteins associated with donor and target membranes suggests lipid transfer mechanisms. Proteins 2023; 91:439-455. [PMID: 36404287 PMCID: PMC10953354 DOI: 10.1002/prot.26446] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/14/2022] [Accepted: 11/03/2022] [Indexed: 11/22/2022]
Abstract
The VPS13 protein family constitutes a novel class of bridge-like lipid transferases. Autosomal recessive inheritance of mutations in VPS13 genes is associated with the development of neurodegenerative diseases in humans. Bioinformatic approaches previously recognized the domain architecture of these proteins. In this study, we model the first ever full-length structures of the four human homologs VPS13A, VPS13B, VPS13C, and VPS13D in association with model membranes, to investigate their lipid transfer ability and potential structural association with membrane leaflets. We analyze the evolutionary conservation and physicochemical properties of these proteins, focusing on conserved C-terminal amphipathic helices that disturb organelle surfaces and that, adjoined, resemble a traditional Venetian gondola. The gondola domains share significant structural homology with lipid droplet surface-binding proteins. We introduce in silico protein-membrane models displaying the mode of association of VPS13A, VPS13B, VPS13C, and VPS13D to donor and target membranes, and present potential models of action for protein-mediated lipid transfer.
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Affiliation(s)
- Filippo Dall'Armellina
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Massimiliano Stagi
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Laura E. Swan
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
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2
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Kraut JA, Cheetham‐Wilkinson IJ, Swan LE, Stagi M, Kurtz I. Impact of Various Buffers and Weak Bases on Lysosomal and Intracellular
pH
: Implications for Infectivity of
SARS‐CoV
‐2. FASEB Bioadv 2023; 5:149-155. [PMID: 37020747 PMCID: PMC10068769 DOI: 10.1096/fba.2022-00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/21/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023] Open
Abstract
Acidification of the cellular lysosome is an important factor in infection of mammalian cells by SARS-CoV-2. Therefore, raising the pH of the lysosome would theoretically be beneficial in prevention or treatment of SARS-CoV-2 infection. Sodium bicarbonate, carbicarb, and THAM are buffers that can be used clinically to provide base to patients. To examine whether these bases could raise lysosomal pH and therefore be a primary or adjunctive treatment of SARS-CoV-2 infection, we measured lysosomal and intracellular pH of mammalian cells after exposure to each of these bases. Mammalian HEK293 cells expressing RpH-LAMP1-3xFLAG, a ratiometric sensor of lysosomal luminal pH, were first exposed to Hepes which was then switched to sodium bicarbonate, carbicarb, or THAM and lysosomal pH measured. In bicarbonate buffer the mean lysosomal pH was 4.3 ± 0.1 (n = 20); p = NS versus Hepes (n = 20). The mean lysosomal pH in bicarbonate/carbonate was 4.3 ± 0.1 (n = 21) versus Hepes (n = 21), p = NS. In THAM buffer the mean lysosomal pH was 4.7 ± 0.07 (n = 20) versus Hepes (4.6 ± 0.1, n = 20), p = NS. In addition, there was no statistical difference between pHi in bicarbonate, carbicarb or THAM solutions. Using the membrane permeable base NH4Cl (5 mM), lysosomal pH increased significantly to 5.9 ± 0.1 (n = 21) compared to Hepes (4.5 ± 0.07, n = 21); p < 0.0001. Similarly, exposure to 1 mM hydroxychloroquine significantly increased the lysosomal pH to (5.9 ± 0.06, n = 20) versus Hepes (4.3 ± 0.1, n = 20), p < 0.0001. Separately steady-state pHi was measured in HEK293 cells bathed in various buffers. In bicarbonate pHi was 7.29 ± 0.02 (n = 12) versus Hepes (7.45 ± 0.03, [n = 12]), p < 0.001. In cells bathed in carbicarb pHi was 7.27 ± 0.02 (n = 5) versus Hepes (7.43 ± 0.04, [n = 5]), p < 0.01. Cells bathed in THAM had a pHi of 7.25 ± 0.03 (n = 12) versus Hepes (7.44 ± 0.03 [n = 12]), p < 0.001. In addition, there was no statistical difference in pHi in bicarbonate, carbicarb or THAM solutions. The results of these studies indicate that none of the buffers designed to provide base to patients alters lysosomal pH at the concentrations used in this study and therefore would be predicted to be of no value in the treatment of SARS-CoV-2 infection. If the goal is to raise lysosomal pH to decrease the infectivity of SARS-CoV-2, utilizing lysosomal permeable buffers at the appropriate dose that is non-toxic appears to be a useful approach to explore.
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Affiliation(s)
- Jeffrey A. Kraut
- Medical and Research Services VHAGLA Healthcare System, UCLA Membrane Biology Laboratory and Division of Nephrology VHAGLA Healthcare System and David Geffen School of Medicine Los Angeles California USA
| | - Izaak J. Cheetham‐Wilkinson
- Department of Cellular and Molecular Physiology, Institute of Systems, Molecular and Integrative Biology University of Liverpool Liverpool
| | - Laura E. Swan
- Department of Cellular and Molecular Physiology, Institute of Systems, Molecular and Integrative Biology University of Liverpool Liverpool
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, Institute of Systems, Molecular and Integrative Biology University of Liverpool Liverpool
| | - Ira Kurtz
- Department of Medicine, Division of Nephrology David Geffen School of Medicine Los Angeles California USA
- UCLA Brain Research Institute Los Angeles California USA
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3
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An SJ, Stagi M, Gould TJ, Wu Y, Mlodzianoski M, Rivera-Molina F, Toomre D, Strittmatter SM, De Camilli P, Bewersdorf J, Zenisek D. Multimodal imaging of synaptic vesicles with a single probe. Cell Rep Methods 2022; 2:100199. [PMID: 35497490 PMCID: PMC9046237 DOI: 10.1016/j.crmeth.2022.100199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/11/2022] [Accepted: 03/28/2022] [Indexed: 05/17/2023]
Abstract
A complete understanding of synaptic-vesicle recycling requires the use of multiple microscopy methods to obtain complementary information. However, many currently available probes are limited to a specific microscopy modality, which necessitates the use of multiple probes and labeling paradigms. Given the complexity of vesicle populations and recycling pathways, having new single-vesicle probes that could be used for multiple microscopy techniques would complement existing sets of tools for studying vesicle function. Here, we present a probe based on the membrane-binding C2 domain of cytosolic phospholipase A2 (cPLA2) that fulfills this need. By conjugating the C2 domain with different detectable tags, we demonstrate that a single, modular probe can allow synaptic vesicles to be imaged at multiple levels of spatial and temporal resolution. Moreover, as a general endocytic marker, the C2 domain may also be used to study membrane recycling in many cell types.
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Affiliation(s)
- Seong J. An
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Massimiliano Stagi
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool 69 3BX, UK
| | - Travis J. Gould
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Physics and Astronomy, Bates College, Lewiston, ME 04240, USA
| | - Yumei Wu
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Michael Mlodzianoski
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Stephen M. Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pietro De Camilli
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - David Zenisek
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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4
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Papoutsopoulou S, Morris L, Bayliff A, Mair T, England H, Stagi M, Bergey F, Alam MT, Sheibani-Tezerji R, Rosenstiel P, Müller W, Martins Dos Santos VAP, Campbell BJ. Effects of Human RelA Transgene on Murine Macrophage Inflammatory Responses. Biomedicines 2022; 10:biomedicines10040757. [PMID: 35453507 PMCID: PMC9027775 DOI: 10.3390/biomedicines10040757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 02/04/2023] Open
Abstract
The NFκB transcription factors are major regulators of innate immune responses, and NFκB signal pathway dysregulation is linked to inflammatory disease. Here, we utilised bone marrow-derived macrophages from the p65-DsRedxp/IκBα-eGFP transgenic strain to study the functional implication of xenogeneic (human) RelA(p65) protein introduced into the mouse genome. Confocal imaging showed that human RelA is expressed in the cells and can translocate to the nucleus following activation of Toll-like receptor 4. RNA sequencing of lipid A-stimulated macrophages, revealed that human RelA impacts on murine gene transcription, affecting both non-NFκB and NFκB target genes, including immediate-early and late response genes, e.g., Fos and Cxcl10. Validation experiments on NFκB targets revealed markedly reduced mRNA levels, but similar kinetic profiles in transgenic cells compared to wild-type. Enrichment pathway analysis of differentially expressed genes revealed interferon and cytokine signaling were affected. These immune response pathways were also affected in macrophages treated with tumor necrosis factor. Data suggests that the presence of xenogeneic RelA protein likely has inhibitory activity, altering specific transcriptional profiles of key molecules involved in immune responses. It is therefore essential that this information be taken into consideration when designing and interpreting future experiments using this transgenic strain.
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Affiliation(s)
- Stamatia Papoutsopoulou
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.E.); (W.M.)
- Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, 413 34 Larissa, Greece
- Correspondence: (S.P.); (B.J.C.)
| | - Lorna Morris
- LifeGlimmer GmbH, Markelstr. 39A, 12163 Berlin, Germany; (L.M.); (F.B.); (V.A.P.M.D.S.)
| | - Andrew Bayliff
- The Henry Wellcome Laboratories of Molecular & Cellular Gastroenterology, Department of Infection Biology & Microbiomes, Institute of Infection Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3GE, UK; (A.B.); (T.M.)
| | - Thomas Mair
- The Henry Wellcome Laboratories of Molecular & Cellular Gastroenterology, Department of Infection Biology & Microbiomes, Institute of Infection Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3GE, UK; (A.B.); (T.M.)
| | - Hazel England
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.E.); (W.M.)
| | - Massimiliano Stagi
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK;
| | - François Bergey
- LifeGlimmer GmbH, Markelstr. 39A, 12163 Berlin, Germany; (L.M.); (F.B.); (V.A.P.M.D.S.)
| | - Mohammad Tauqeer Alam
- Warwick Medical School, Bioinformatics RTP, University of Warwick, Coventry CV4 7AL, UK;
- Department of Biology, College of Science, United Arab Emirates University, Abu Dhabi P.O. Box 15551, United Arab Emirates
| | - Raheleh Sheibani-Tezerji
- Institute of Clinical Molecular Biology, Christian Albrechts University of Kiel, 6708 WE Kiel, Germany; (R.S.-T.); (P.R.)
| | - Philip Rosenstiel
- Institute of Clinical Molecular Biology, Christian Albrechts University of Kiel, 6708 WE Kiel, Germany; (R.S.-T.); (P.R.)
| | - Werner Müller
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (H.E.); (W.M.)
| | - Vitor A. P. Martins Dos Santos
- LifeGlimmer GmbH, Markelstr. 39A, 12163 Berlin, Germany; (L.M.); (F.B.); (V.A.P.M.D.S.)
- Laboratory of Systems & Synthetic Biology, Wageningen University & Research, P.O. Box 8033, 6700 EJ Wageningen, The Netherlands
| | - Barry J. Campbell
- The Henry Wellcome Laboratories of Molecular & Cellular Gastroenterology, Department of Infection Biology & Microbiomes, Institute of Infection Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 3GE, UK; (A.B.); (T.M.)
- Correspondence: (S.P.); (B.J.C.)
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5
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Ponsford AH, Ryan TA, Raimondi A, Cocucci E, Wycislo SA, Fröhlich F, Swan LE, Stagi M. Live imaging of intra-lysosome pH in cell lines and primary neuronal culture using a novel genetically encoded biosensor. Autophagy 2021; 17:1500-1518. [PMID: 32515674 PMCID: PMC8205096 DOI: 10.1080/15548627.2020.1771858] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 12/11/2022] Open
Abstract
Disorders of lysosomal physiology have increasingly been found to underlie the pathology of a rapidly growing cast of neurodevelopmental disorders and sporadic diseases of aging. One cardinal aspect of lysosomal (dys)function is lysosomal acidification in which defects trigger lysosomal stress signaling and defects in proteolytic capacity. We have developed a genetically encoded ratiometric probe to measure lysosomal pH coupled with a purification tag to efficiently purify lysosomes for both proteomic and in vitro evaluation of their function. Using our probe, we showed that lysosomal pH is remarkably stable over a period of days in a variety of cell types. Additionally, this probe can be used to determine that lysosomal stress signaling via TFEB is uncoupled from gross changes in lysosomal pH. Finally, we demonstrated that while overexpression of ARL8B GTPase causes striking alkalinization of peripheral lysosomes in HEK293 T cells, peripheral lysosomes per se are no less acidic than juxtanuclear lysosomes in our cell lines.Abbreviations: ARL8B: ADP ribosylation factor like GTPase 8B; ATP: adenosine triphosphate; ATP5F1B/ATPB: ATP synthase F1 subunit beta; ATP6V1A: ATPase H+ transporting V1 subunit A; Baf: bafilomycin A1; BLOC-1: biogenesis of lysosome-related organelles complex 1; BSA: bovine serum albumin; Cos7: African green monkey kidney fibroblast-like cell line; CQ: chloroquine; CTSB: cathepsin B; CYCS: cytochrome c, somatic; DAPI: 4',6-diamidino -2- phenylindole; DIC: differential interference contrast; DIV: days in vitro; DMEM: Dulbecco's modified Eagle's medium; E8: embryonic day 8; EEA1: early endosome antigen 1; EGTA: ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid; ER: endoplasmic reticulum; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GABARAPL2: GABA type A receptor associated protein like 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GOLGA2/GM130: golgin A2; GTP: guanosine triphosphate; HEK293T: human embryonic kidney 293 cells, that expresses a mutant version of the SV40 large T antigen; HeLa: Henrietta Lacks-derived cell; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; HRP: horseradish peroxidase; IGF2R/ciM6PR: insulin like growth factor 2 receptor; LAMP1/2: lysosomal associated membrane protein 1/2; LMAN2/VIP36: lectin, mannose binding 2; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; PCR: polymerase chain reaction; PDL: poly-d-lysine; PGK1p: promotor from human phosphoglycerate kinase 1; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PPT1/CLN1: palmitoyl-protein thioesterase 1; RPS6KB1/p70: ribosomal protein S6 kinase B1; STAT3: signal transducer and activator of transcription 3; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGN: trans-Golgi network; TGOLN2/TGN46: trans-Golgi network protein 2; TIRF: total internal reflection fluorescence; TMEM106B: transmembrane protein 106B; TOR: target of rapamycin; TRPM2: transient receptor potential cation channel subfamily M member 2; V-ATPase: vacuolar-type proton-translocating ATPase; VPS35: VPS35 retromer complex component.
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Affiliation(s)
- Amy H. Ponsford
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Thomas A. Ryan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andrea Raimondi
- Experimental Imaging Center, San Raffaele Scientific Institute, Milan, Italy
| | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and the Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Susanne A. Wycislo
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
- Centre of Cellular Nanoanalytics (CellNanOs), University of Osnabrück, Osnabrück, Osnabrück, Germany
| | - Laura E. Swan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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6
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Affiliation(s)
- Alessandro Luciani
- Mechanisms of Inherited Kidney Diseases Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.
| | - Massimiliano Stagi
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool, UK
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7
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Luscher A, Fröhlich F, Barisch C, Littlewood C, Metcalfe J, Leuba F, Palma A, Pirruccello M, Cesareni G, Stagi M, Walther TC, Soldati T, De Camilli P, Swan LE. Lowe syndrome-linked endocytic adaptors direct membrane cycling kinetics with OCRL in Dictyostelium discoideum. Mol Biol Cell 2019; 30:2268-2282. [PMID: 31216233 PMCID: PMC6743453 DOI: 10.1091/mbc.e18-08-0510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mutations of the inositol 5-phosphatase OCRL cause Lowe syndrome (LS), characterized by congenital cataract, low IQ, and defective kidney proximal tubule resorption. A key subset of LS mutants abolishes OCRL’s interactions with endocytic adaptors containing F&H peptide motifs. Converging unbiased methods examining human peptides and the unicellular phagocytic organism Dictyostelium discoideum reveal that, like OCRL, the Dictyostelium OCRL orthologue Dd5P4 binds two proteins closely related to the F&H proteins APPL1 and Ses1/2 (also referred to as IPIP27A/B). In addition, a novel conserved F&H interactor was identified, GxcU (in Dictyostelium) and the Cdc42-GEF FGD1-related F-actin binding protein (Frabin) (in human cells). Examining these proteins in D. discoideum, we find that, like OCRL, Dd5P4 acts at well-conserved and physically distinct endocytic stations. Dd5P4 functions in coordination with F&H proteins to control membrane deformation at multiple stages of endocytosis and suppresses GxcU-mediated activity during fluid-phase micropinocytosis. We also reveal that OCRL/Dd5P4 acts at the contractile vacuole, an exocytic osmoregulatory organelle. We propose F&H peptide-containing proteins may be key modifiers of LS phenotypes.
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Affiliation(s)
- Alexandre Luscher
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Florian Fröhlich
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Caroline Barisch
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Clare Littlewood
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Joe Metcalfe
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Florence Leuba
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Anita Palma
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Michelle Pirruccello
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Gianni Cesareni
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510.,Department of Neuroscience and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510
| | - Laura E Swan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510.,Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
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8
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Fernandez-Mosquera L, Yambire KF, Couto R, Pereyra L, Pabis K, Ponsford AH, Diogo CV, Stagi M, Milosevic I, Raimundo N. Mitochondrial respiratory chain deficiency inhibits lysosomal hydrolysis. Autophagy 2019; 15:1572-1591. [PMID: 30917721 PMCID: PMC6693470 DOI: 10.1080/15548627.2019.1586256] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mitochondria are key organelles for cellular metabolism, and regulate several processes including cell death and macroautophagy/autophagy. Here, we show that mitochondrial respiratory chain (RC) deficiency deactivates AMP-activated protein kinase (AMPK, a key regulator of energy homeostasis) signaling in tissue and in cultured cells. The deactivation of AMPK in RC-deficiency is due to increased expression of the AMPK-inhibiting protein FLCN (folliculin). AMPK is found to be necessary for basal lysosomal function, and AMPK deactivation in RC-deficiency inhibits lysosomal function by decreasing the activity of the lysosomal Ca2+ channel MCOLN1 (mucolipin 1). MCOLN1 is regulated by phosphoinositide kinase PIKFYVE and its product PtdIns(3,5)P2, which is also decreased in RC-deficiency. Notably, reactivation of AMPK, in a PIKFYVE-dependent manner, or of MCOLN1 in RC-deficient cells, restores lysosomal hydrolytic capacity. Building on these data and the literature, we propose that downregulation of the AMPK-PIKFYVE-PtdIns(3,5)P2-MCOLN1 pathway causes lysosomal Ca2+ accumulation and impaired lysosomal catabolism. Besides unveiling a novel role of AMPK in lysosomal function, this study points to the mechanism that links mitochondrial malfunction to impaired lysosomal catabolism, underscoring the importance of AMPK and the complexity of organelle cross-talk in the regulation of cellular homeostasis. Abbreviation: ΔΨm: mitochondrial transmembrane potential; AMP: adenosine monophosphate; AMPK: AMP-activated protein kinase; ATG5: autophagy related 5; ATP: adenosine triphosphate; ATP6V0A1: ATPase, H+ transporting, lysosomal, V0 subbunit A1; ATP6V1A: ATPase, H+ transporting, lysosomal, V0 subbunit A; BSA: bovine serum albumin; CCCP: carbonyl cyanide-m-chlorophenylhydrazone; CREB1: cAMP response element binding protein 1; CTSD: cathepsin D; CTSF: cathepsin F; DMEM: Dulbecco’s modified Eagle’s medium; DMSO: dimethyl sulfoxide; EBSS: Earl’s balanced salt solution; ER: endoplasmic reticulum; FBS: fetal bovine serum; FCCP: carbonyl cyanide-p-trifluoromethoxyphenolhydrazone; GFP: green fluorescent protein; GPN: glycyl-L-phenylalanine 2-naphthylamide; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MCOLN1/TRPML1: mucolipin 1; MEF: mouse embryonic fibroblast; MITF: melanocyte inducing transcription factor; ML1N*2-GFP: probe used to detect PtdIns(3,5)P2 based on the transmembrane domain of MCOLN1; MTORC1: mechanistic target of rapamycin kinase complex 1; NDUFS4: NADH:ubiquinone oxidoreductase subunit S4; OCR: oxygen consumption rate; PBS: phosphate-buffered saline; pcDNA: plasmid cytomegalovirus promoter DNA; PCR: polymerase chain reaction; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns(3,5)P2: phosphatidylinositol-3,5-bisphosphate; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; P/S: penicillin-streptomycin; PVDF: polyvinylidene fluoride; qPCR: quantitative real time polymerase chain reaction; RFP: red fluorescent protein; RNA: ribonucleic acid; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; shRNA: short hairpin RNA; siRNA: small interfering RNA; TFEB: transcription factor EB; TFE3: transcription factor binding to IGHM enhancer 3; TMRM: tetramethylrhodamine, methyl ester, perchlorate; ULK1: unc-51 like autophagy activating kinase 1; ULK2: unc-51 like autophagy activating kinase 2; UQCRC1: ubiquinol-cytochrome c reductase core protein 1; v-ATPase: vacuolar-type H+-translocating ATPase; WT: wild-type
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Affiliation(s)
- Lorena Fernandez-Mosquera
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,b Doctoral Program in Molecular Medicine, Georg August University Goettingen , Goettingen , Germany
| | - King Faisal Yambire
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,c International Max-Planck Research School in Neuroscience , Goettingen , Germany.,d European Neuroscience Institute Goettingen, University Medical Center Goettingen and Max-Planck Society , Goettingen , Germany
| | - Renata Couto
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,e Doctoral Program in Molecular Biology of Cells, Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Goettingen , Goettingen , Germany
| | - Leonardo Pereyra
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany.,e Doctoral Program in Molecular Biology of Cells, Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Goettingen , Goettingen , Germany
| | - Kamil Pabis
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
| | - Amy H Ponsford
- f Institute of Translational Medicine, University of Liverpool , Liverpool , UK
| | - Cátia V Diogo
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
| | - Massimiliano Stagi
- f Institute of Translational Medicine, University of Liverpool , Liverpool , UK
| | - Ira Milosevic
- d European Neuroscience Institute Goettingen, University Medical Center Goettingen and Max-Planck Society , Goettingen , Germany
| | - Nuno Raimundo
- a Institute of Cellular Biochemistry, University Medical Center Goettingen , Goettingen , Germany
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9
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Gunther EC, Smith LM, Kostylev MA, Cox TO, Kaufman AC, Lee S, Folta-Stogniew E, Maynard GD, Um JW, Stagi M, Heiss JK, Stoner A, Noble GP, Takahashi H, Haas LT, Schneekloth JS, Merkel J, Teran C, Naderi ZK, Supattapone S, Strittmatter SM. Rescue of Transgenic Alzheimer's Pathophysiology by Polymeric Cellular Prion Protein Antagonists. Cell Rep 2019; 26:145-158.e8. [PMID: 30605671 PMCID: PMC6358723 DOI: 10.1016/j.celrep.2018.12.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/17/2018] [Accepted: 12/05/2018] [Indexed: 10/27/2022] Open
Abstract
Cellular prion protein (PrPC) binds the scrapie conformation of PrP (PrPSc) and oligomeric β-amyloid peptide (Aβo) to mediate transmissible spongiform encephalopathy (TSE) and Alzheimer's disease (AD), respectively. We conducted cellular and biochemical screens for compounds blocking PrPC interaction with Aβo. A polymeric degradant of an antibiotic targets Aβo binding sites on PrPC with low nanomolar affinity and prevents Aβo-induced pathophysiology. We then identified a range of negatively charged polymers with specific PrPC affinity in the low to sub-nanomolar range, from both biological (melanin) and synthetic (poly [4-styrenesulfonic acid-co-maleic acid], PSCMA) origin. Association of PSCMA with PrPC prevents Aβo/PrPC-hydrogel formation, blocks Aβo binding to neurons, and abrogates PrPSc production by ScN2a cells. We show that oral PSCMA yields effective brain concentrations and rescues APPswe/PS1ΔE9 transgenic mice from AD-related synapse loss and memory deficits. Thus, an orally active PrPC-directed polymeric agent provides a potential therapeutic approach to address neurodegeneration in AD and TSE.
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Affiliation(s)
- Erik C Gunther
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Levi M Smith
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Mikhail A Kostylev
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Timothy O Cox
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Adam C Kaufman
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Suho Lee
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Ewa Folta-Stogniew
- W.M. Keck Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, CT 06511, USA
| | | | - Ji Won Um
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Massimiliano Stagi
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Jacqueline K Heiss
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Austin Stoner
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Geoff P Noble
- Departments of Biochemistry, Cell Biology, and Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Hideyuki Takahashi
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Laura T Haas
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - John S Schneekloth
- Yale Center for Molecular Discovery, Yale University, 600 West Campus Drive, West Haven, CT 06516, USA
| | - Janie Merkel
- Yale Center for Molecular Discovery, Yale University, 600 West Campus Drive, West Haven, CT 06516, USA
| | - Christopher Teran
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Zahra K Naderi
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Surachai Supattapone
- Departments of Biochemistry, Cell Biology, and Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Stephen M Strittmatter
- Cellular Neuroscience, Neurodegeneration, Repair, Departments of Neurology and of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA.
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10
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Gunther EC, Smith LM, Kostylev MA, Cox TO, Kaufman AC, Lee S, Folta-Stogniew E, Maynard GD, Um JW, Stagi M, Heiss JK, Stoner A, Noble GP, Takahashi H, Haas LT, Schneekloth JS, Merkel J, Teran C, Naderi ZK, Supattapone S, Strittmatter SM. Rescue of Transgenic Alzheimer's Pathophysiology by Polymeric Cellular Prion Protein Antagonists. Cell Rep 2019; 26:1368. [PMID: 30699361 PMCID: PMC6424100 DOI: 10.1016/j.celrep.2019.01.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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11
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Stagi M, Klein ZA, Gould TJ, Bewersdorf J, Strittmatter SM. Lysosome size, motility and stress response regulated by fronto-temporal dementia modifier TMEM106B. Mol Cell Neurosci 2014; 61:226-40. [PMID: 25066864 PMCID: PMC4145808 DOI: 10.1016/j.mcn.2014.07.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 12/14/2022] Open
Abstract
Fronto-temporal lobar degeneration with TDP-43 (FTLD-TDP) is a fatal neurodegeneration. TMEM106B variants are linked to FTLD-TDP risk, and TMEM106B is lysosomal. Here, we focus on neuronal TMEM106B, and demonstrate co-localization and traffic with lysosomal LAMP-1. pH-sensitive reporters demonstrate that the TMEM106B C-terminus is lumenal. The TMEM106B N-terminus interacts with endosomal adaptors and other TMEM106 proteins. TMEM106B knockdown reduces neuronal lysosomal number and diameter by STED microscopy, and overexpression enlarges LAMP-positive structures. Reduction of TMEM106B increases axonally transported lysosomes, while TMEM106B elevation inhibits transport and yields large lysosomes in the soma. TMEM106B overexpression alters lysosomal stress signaling, causing a translocation of the mTOR-sensitive transcription factor, TFEB, to neuronal nuclei. TMEM106B loss-of-function delays TFEB translocation after Torin-1-induced stress. Enlarged TMEM106B-overexpressing lysosomes maintain organelle integrity longer after lysosomal photodamage than do control lysosomes, while small TMEM106B-knockdown lysosomes are more sensitive to illumination. Thus, neuronal TMEM106B plays a central role in regulating lysosomal size, motility and responsiveness to stress, highlighting the possible role of lysosomal biology in FTLD-TDP.
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Affiliation(s)
- Massimiliano Stagi
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Zoe A Klein
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Travis J Gould
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Stephen M Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.
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12
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Um JW, Kaufman AC, Kostylev M, Heiss JK, Stagi M, Takahashi H, Kerrisk ME, Vortmeyer A, Wisniewski T, Koleske AJ, Gunther EC, Nygaard HB, Strittmatter SM. Metabotropic glutamate receptor 5 is a coreceptor for Alzheimer aβ oligomer bound to cellular prion protein. Neuron 2013; 79:887-902. [PMID: 24012003 DOI: 10.1016/j.neuron.2013.06.036] [Citation(s) in RCA: 428] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2013] [Indexed: 02/07/2023]
Abstract
Soluble amyloid-β oligomers (Aβo) trigger Alzheimer's disease (AD) pathophysiology and bind with high affinity to cellular prion protein (PrP(C)). At the postsynaptic density (PSD), extracellular Aβo bound to lipid-anchored PrP(C) activates intracellular Fyn kinase to disrupt synapses. Here, we screened transmembrane PSD proteins heterologously for the ability to couple Aβo-PrP(C) with Fyn. Only coexpression of the metabotropic glutamate receptor, mGluR5, allowed PrP(C)-bound Aβo to activate Fyn. PrP(C) and mGluR5 interact physically, and cytoplasmic Fyn forms a complex with mGluR5. Aβo-PrP(C) generates mGluR5-mediated increases of intracellular calcium in Xenopus oocytes and in neurons, and the latter is also driven by human AD brain extracts. In addition, signaling by Aβo-PrP(C)-mGluR5 complexes mediates eEF2 phosphorylation and dendritic spine loss. For mice expressing familial AD transgenes, mGluR5 antagonism reverses deficits in learning, memory, and synapse density. Thus, Aβo-PrP(C) complexes at the neuronal surface activate mGluR5 to disrupt neuronal function.
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Affiliation(s)
- Ji Won Um
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT 06536, USA
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13
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Um J, Kaufman A, Kostylev M, Heiss J, Stagi M, Takahashi H, Kerrisk M, Vortmeyer A, Wisniewski T, Koleske A, Gunther E, Nygaard H, Strittmatter S. Metabotropic Glutamate Receptor 5 Is a Coreceptor for Alzheimer Aβ Oligomer Bound to Cellular Prion Protein. Neuron 2013. [DOI: 10.1016/j.neuron.2013.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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14
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Um JW, Nygaard HB, Heiss JK, Kostylev MA, Stagi M, Vortmeyer A, Wisniewski T, Gunther EC, Strittmatter SM. Alzheimer amyloid-β oligomer bound to postsynaptic prion protein activates Fyn to impair neurons. Nat Neurosci 2012; 15:1227-35. [PMID: 22820466 PMCID: PMC3431439 DOI: 10.1038/nn.3178] [Citation(s) in RCA: 487] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/02/2012] [Indexed: 12/21/2022]
Abstract
Amyloid-beta (Aβ) oligomers are thought to trigger Alzheimer’s disease (AD) pathophysiology. Cellular Prion Protein (PrPC) selectively binds oligomeric Aβ and can mediate AD-related phenotypes. Here, we examined the specificity, distribution and signaling from Aβ/PrP complexes, seeking to explain how they might alter the function of NMDA receptors in neurons. PrPC is enriched in post-synaptic densities, and Aβ/PrPC interaction leads to Fyn kinase activation. Soluble Aβ assemblies derived from human AD brain interact with PrPC to activate Fyn. Aβ engagement of PrPC/Fyn signaling yields phosphorylation of the NR2B subunit of NMDA-receptors, which is coupled to an initial increase and then loss of surface NMDA-receptors. Aβ-induced LDH release and dendritic spine loss require both PrPC and Fyn, and human familial AD transgene-induced convulsive seizures do not occur in mice lacking PrPC. These results delineate an Aβ oligomer signal transduction pathway requiring PrPC and Fyn to alter synaptic function with relevance to AD.
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Affiliation(s)
- Ji Won Um
- Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
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15
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Fogel AI, Stagi M, Perez de Arce K, Biederer T. Lateral assembly of the immunoglobulin protein SynCAM 1 controls its adhesive function and instructs synapse formation. EMBO J 2011; 30:4728-38. [PMID: 21926970 DOI: 10.1038/emboj.2011.336] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 08/18/2011] [Indexed: 11/09/2022] Open
Abstract
Synapses are specialized adhesion sites between neurons that are connected by protein complexes spanning the synaptic cleft. These trans-synaptic interactions can organize synapse formation, but their macromolecular properties and effects on synaptic morphology remain incompletely understood. Here, we demonstrate that the synaptic cell adhesion molecule SynCAM 1 self-assembles laterally via its extracellular, membrane-proximal immunoglobulin (Ig) domains 2 and 3. This cis oligomerization generates SynCAM oligomers with increased adhesive capacity and instructs the interactions of this molecule across the nascent and mature synaptic cleft. In immature neurons, cis assembly promotes the adhesive clustering of SynCAM 1 at new axo-dendritic contacts. Interfering with the lateral self-assembly of SynCAM 1 in differentiating neurons strongly impairs its synaptogenic activity. At later stages, the lateral oligomerization of SynCAM 1 restricts synaptic size, indicating that this adhesion molecule contributes to the structural organization of synapses. These results support that lateral interactions assemble SynCAM complexes within the synaptic cleft to promote synapse induction and modulate their structure. These findings provide novel insights into synapse development and the adhesive mechanisms of Ig superfamily members.
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Affiliation(s)
- Adam I Fogel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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Abstract
Multiple signaling pathways initiate and specify the formation of synapses in the central nervous system. General principles that organize nascent synapses have emerged from the studies in multiple model organisms. These include the synapse-organizing roles of dedicated synaptic adhesion molecules, synaptic signaling following receptor-ligand interactions, and the regulation of synapse formation by secreted molecules. Intracellularly, a range of effectors subsequently regulates signaling steps and cytoskeletal changes. Together, a blueprint of synapse formation is emerging into which these distinct signaling steps will need to be integrated temporally and spatially.
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Affiliation(s)
- Thomas Biederer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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17
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Fogel A, Stagi M, Krupp A, Stein V, Biederer T. [SY7.3]: SynCAM complexes encode synaptic adhesion to organize nascent synapses. Int J Dev Neurosci 2008. [DOI: 10.1016/j.ijdevneu.2008.09.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
| | | | - A.J. Krupp
- Max Planck Institute of NeurobiologyGermany
| | - V. Stein
- Max Planck Institute of NeurobiologyGermany
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18
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Takahashi K, Prinz M, Stagi M, Chechneva O, Neumann H. TREM2-transduced myeloid precursors mediate nervous tissue debris clearance and facilitate recovery in an animal model of multiple sclerosis. PLoS Med 2007; 4:e124. [PMID: 17425404 PMCID: PMC1851623 DOI: 10.1371/journal.pmed.0040124] [Citation(s) in RCA: 301] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 02/07/2007] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND In multiple sclerosis, inflammation can successfully be prevented, while promoting repair is still a major challenge. Microglial cells, the resident phagocytes of the central nervous system (CNS), are hematopoietic-derived myeloid cells and express the triggering receptor expressed on myeloid cells 2 (TREM2), an innate immune receptor. Myeloid cells are an accessible source for ex vivo gene therapy. We investigated whether myeloid precursor cells genetically modified to express TREM2 affect the disease course of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. METHODS AND FINDINGS EAE was induced in mice by immunization with a myelin autoantigen. Intravenous application of TREM2-transduced bone marrow-derived myeloid precursor cells at the EAE peak led to an amelioration of clinical symptoms, reduction in axonal damage, and prevention of further demyelination. TREM2-transduced myeloid cells applied intravenously migrated into the inflammatory spinal cord lesions of EAE-diseased mice, showed increased lysosomal and phagocytic activity, cleared degenerated myelin, and created an anti-inflammatory cytokine milieu within the CNS. CONCLUSIONS Intravenously applied bone marrow-derived and TREM2-tranduced myeloid precursor cells limit tissue destruction and facilitate repair within the murine CNS by clearance of cellular debris during EAE. TREM2 is a new attractive target for promotion of repair and resolution of inflammation in multiple sclerosis and other neuroinflammatory diseases.
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MESH Headings
- Animals
- Apoptosis
- Cell Differentiation/drug effects
- Cell Lineage
- Cell Movement
- Cells, Cultured/physiology
- Cells, Cultured/transplantation
- Cytokines/biosynthesis
- Cytokines/genetics
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/surgery
- Encephalomyelitis, Autoimmune, Experimental/therapy
- Female
- Flow Cytometry
- Gene Expression Regulation
- Genes, Reporter
- Genes, Synthetic
- Genetic Therapy
- Genetic Vectors/genetics
- Genetic Vectors/therapeutic use
- Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology
- Hematopoietic Stem Cell Transplantation
- Humans
- Interleukin-10/biosynthesis
- Interleukin-10/genetics
- Lentivirus/genetics
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C57BL
- Microglia/physiology
- Monocytes/physiology
- Multiple Sclerosis
- Myeloid Cells/drug effects
- Myeloid Cells/physiology
- Myeloid Cells/transplantation
- Neurons/pathology
- Nitric Oxide Synthase Type II/biosynthesis
- Nitric Oxide Synthase Type II/genetics
- Phagocytosis
- Promoter Regions, Genetic
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Transduction, Genetic
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Affiliation(s)
- Kazuya Takahashi
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, University of Bonn Life & Brain Center and Hertie-Foundation, Bonn, Germany
- Neuroimmunology Unit, European Neuroscience Institute Göttingen, Göttingen, Germany
| | - Marco Prinz
- Department of Neuropathology, University Hospital Göttingen, Göttingen, Germany
| | - Massimiliano Stagi
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, University of Bonn Life & Brain Center and Hertie-Foundation, Bonn, Germany
- Neuroimmunology Unit, European Neuroscience Institute Göttingen, Göttingen, Germany
- Institute of Multiple Sclerosis Research, University of Göttingen and Hertie-Foundation, Germany
| | - Olga Chechneva
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, University of Bonn Life & Brain Center and Hertie-Foundation, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, University of Bonn Life & Brain Center and Hertie-Foundation, Bonn, Germany
- Neuroimmunology Unit, European Neuroscience Institute Göttingen, Göttingen, Germany
- Institute of Multiple Sclerosis Research, University of Göttingen and Hertie-Foundation, Germany
- * To whom correspondence should be addressed. E-mail:
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Stagi M, Gorlovoy P, Larionov S, Takahashi K, Neumann H. Unloading kinesin transported cargoes from the tubulin track via the inflammatory c‐Jun N‐terminal kinase pathway. FASEB J 2006; 20:2573-5. [PMID: 17068110 DOI: 10.1096/fj.06-6679fje] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Axonal transport of mitochondria and synaptic vesicle precursors via kinesin motor proteins is essential to keep integrity of axons and synapses. Disturbance of axonal transport is an early sign of neuroinflammatory and neurodegenerative diseases. Treatment of cultured neurons by the inflammatory cytokine tumor necrosis factor-alpha (TNF) stimulated phosphorylation of c-Jun N-terminal kinase (JNK) in neurites. TNF treatment induced dissociation of the heavy chain kinesin family-5B (KIF5B) protein from tubulin in axons but not cell bodies as determined by lifetime-based Förster resonance energy transfer (FRET) analysis. Dissociation of KIF5B from tubulin after TNF treatment was dependent on JNK activity. Furthermore, TNF inhibited axonal transport of mitochondria and synaptophysin by reducing the mobile fraction via JNK. Thus, TNF produced by activated glial cells in inflammatory or degenerative neurological diseases acts on neurites by acting on the kinesin-tubulin complex and inhibits axonal mitochondria and synaptophysin transport via JNK.
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Affiliation(s)
- Massimiliano Stagi
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, University Bonn Life and Brain Center, University Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
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Abstract
The mechanism of axonal injury in inflammatory brain diseases is still unclear. Increased microglial production of nitric oxide (NO) is a common early sign in neuroinflammatory diseases. We found by fluorescence correlation spectroscopy that synaptophysin tagged with enhanced green fluorescence protein (synaptophysin-EGFP) moves anterogradely in axons of cultured neurons. Activated microglia focally inhibited the axonal movement of synaptophysin-EGFP in a NO synthase-dependent manner. Direct application of a NO donor to neurons resulted in inhibition of axonal transport of synaptophysin-EGFP and synaptotagmin I tagged with EGFP, mediated via phosphorylation of c-jun NH2-terminal kinase (JNK). Thus, overt production of reactive NO by activated microglia blocks the axonal transport of synaptic vesicle precursors via phosphorylation of JNK and could cause axonal and synaptic dysfunction.
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Affiliation(s)
- Massimiliano Stagi
- Neuroimmunology Group, European Neuroscience Institute Göttingen, 37073 Göttingen, Germany
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Liu Y, Walter S, Stagi M, Cherny D, Letiembre M, Schulz-Schaeffer W, Heine H, Penke B, Neumann H, Fassbender K. LPS receptor (CD14): a receptor for phagocytosis of Alzheimer's amyloid peptide. ACTA ACUST UNITED AC 2005; 128:1778-89. [PMID: 15857927 DOI: 10.1093/brain/awh531] [Citation(s) in RCA: 257] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The amyloid beta peptide 42 (Abeta(42)) plays a key role in neurotoxicity in Alzheimer's disease. Mononuclear phagocytes, i.e. microglia, have the potential to clear Abeta by phagocytosis. Recently, the lipopolysaccharide (LPS) receptor CD14 was shown to mediate phagocytosis of bacterial components and furthermore to contribute to neuroinflammation in Alzheimer's disease. Here, we investigated whether this key innate immunity receptor can interact with Abeta(42) and mediate phagocytosis of this peptide. Using flow cytometry, confocal microscopy and two-photon fluorescence lifetime imaging (FLIM) combined with fluorescence resonance energy transfer (FRET), we demonstrated a direct molecular interaction in the range of a few nanometers between Abeta(42) and CD14 in human CD14-transfected Chinese hamster ovary cells. Investigations using cells that were genetically deficient for this receptor showed that in <30 minutes exogenous Abeta(42) added to cultured primary microglial cells was phagocytosed into the cytoplasmic compartment in a CD14-dependent manner. This phagocytosis occurred at Abeta(42) concentration ranges that were considerably lower than the threshold to activate a cellular inflammatory reaction. In contrast, there was no association of CD14 to microglial internalization of microbeads. In complementary clinical experiments, we detected a pronounced CD14 immunoreactivity on parenchymal microglia spatially correlated to characteristic Alzheimer's disease lesion sites in brain sections of Alzheimer's disease patients but not in brain sections of control subjects. By showing a close interaction between CD14 and Abeta(42), demonstrating a direct role of CD14 in Abeta(42) phagocytosis, and detecting CD14-specific staining in brains of Alzheimer's disease patients, our results indicate a role of the LPS receptor in the pathophysiology of Alzheimer's disease, which could be of therapeutic relevance.
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Affiliation(s)
- Yang Liu
- Department of Neurology, University of Göttingen, Germany.
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