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Rudd JC, Maity S, Grunkemeyer JA, Snyder JC, Lovas S, Hansen LA. Membrane structure and internalization dynamics of human Flower isoforms hFWE3 and hFWE4 indicate a conserved endocytic role for hFWE4. J Biol Chem 2023; 299:104945. [PMID: 37348560 PMCID: PMC10366549 DOI: 10.1016/j.jbc.2023.104945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023] Open
Abstract
Human Flower (hFWE) isoforms hFWE1-4 are putative transmembrane (TM) proteins that reportedly mediate fitness comparisons during cell competition through extracellular display of their C-terminal tails. Isoform topology, subcellular localization, and duration of plasma membrane presentation are essential to this function. However, disagreement persists regarding the structure of orthologous fly and mouse FWEs, and experimental evidence for hFWE isoform subcellular localization or membrane structure is lacking. Here, we used AlphaFold2 and subsequent molecular dynamics-based structural predictions to construct epitope-tagged hFWE3 and hFWE4, the most abundant human isoforms, for experimental determination of their structure and internalization dynamics. We demonstrate that hFWE3 resides in the membrane of the endoplasmic reticulum (ER), while hFWE4 partially colocalizes with Rab4-, Rab5-, and Rab11-positive vesicles as well as with the plasma membrane. An array of imaging techniques revealed that hFWE4 positions both N- and C-terminal tails and a loop between second and third TM segments within the cytosol, while small (4-12aa) loops between the first and second and the third and fourth TM segments are either exposed to the extracellular space or within the lumen of cytoplasmic vesicles. Similarly, we found hFWE3 positions both N- and C-terminal tails in the cytosol, while a short loop between TM domains extends into the ER lumen. Finally, we demonstrate that hFWE4 exists only transiently at the cell surface and is rapidly internalized in an AP-2- and dynamin-1-dependent manner. Collectively, these data are consistent with a conserved role for hFWE4 in endocytic processes.
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Affiliation(s)
- Justin C Rudd
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA
| | - Sibaprasad Maity
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA
| | - James A Grunkemeyer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA
| | - Joshua C Snyder
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Sándor Lovas
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA
| | - Laura A Hansen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA.
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2
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Chandra S, Mannino PJ, Thaller DJ, Ader NR, King MC, Melia TJ, Lusk CP. Atg39 selectively captures inner nuclear membrane into lumenal vesicles for delivery to the autophagosome. J Cell Biol 2021; 220:e202103030. [PMID: 34714326 PMCID: PMC8575018 DOI: 10.1083/jcb.202103030] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 08/26/2021] [Accepted: 09/29/2021] [Indexed: 12/26/2022] Open
Abstract
Mechanisms that turn over components of the nucleus and inner nuclear membrane (INM) remain to be fully defined. We explore how components of the INM are selected by a cytosolic autophagy apparatus through a transmembrane nuclear envelope-localized cargo adaptor, Atg39. A split-GFP reporter showed that Atg39 localizes to the outer nuclear membrane (ONM) and thus targets the INM across the nuclear envelope lumen. Consistent with this, sequence elements that confer both nuclear envelope localization and a membrane remodeling activity are mapped to the Atg39 lumenal domain; these lumenal motifs are required for the autophagy-mediated degradation of integral INM proteins. Interestingly, correlative light and electron microscopy shows that the overexpression of Atg39 leads to the expansion of the ONM and the enclosure of a network of INM-derived vesicles in the nuclear envelope lumen. Thus, we propose an outside-in model of nucleophagy where INM is delivered into vesicles in the nuclear envelope lumen, which can be targeted by the autophagosome.
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Affiliation(s)
| | | | | | | | | | - Thomas J. Melia
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - C. Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
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3
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Roney JC, Li S, Farfel-Becker T, Huang N, Sun T, Xie Y, Cheng XT, Lin MY, Platt FM, Sheng ZH. Lipid-mediated motor-adaptor sequestration impairs axonal lysosome delivery leading to autophagic stress and dystrophy in Niemann-Pick type C. Dev Cell 2021; 56:1452-1468.e8. [PMID: 33878344 PMCID: PMC8137671 DOI: 10.1016/j.devcel.2021.03.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [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: 09/10/2020] [Revised: 01/28/2021] [Accepted: 03/28/2021] [Indexed: 01/18/2023]
Abstract
Niemann-Pick disease type C (NPC) is a neurodegenerative lysosomal storage disorder characterized by lipid accumulation in endolysosomes. An early pathologic hallmark is axonal dystrophy occurring at presymptomatic stages in NPC mice. However, the mechanisms underlying this pathologic change remain obscure. Here, we demonstrate that endocytic-autophagic organelles accumulate in NPC dystrophic axons. Using super-resolution and live-neuron imaging, we reveal that elevated cholesterol on NPC lysosome membranes sequesters kinesin-1 and Arl8 independent of SKIP and Arl8-GTPase activity, resulting in impaired lysosome transport into axons, contributing to axonal autophagosome accumulation. Pharmacologic reduction of lysosomal membrane cholesterol with 2-hydroxypropyl-β-cyclodextrin (HPCD) or elevated Arl8b expression rescues lysosome transport, thereby reducing axonal autophagic stress and neuron death in NPC. These findings demonstrate a pathological mechanism by which altered membrane lipid composition impairs lysosome delivery into axons and provide biological insights into the translational application of HPCD in restoring axonal homeostasis at early stages of NPC disease.
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Affiliation(s)
- Joseph C Roney
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA; Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Sunan Li
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Tamar Farfel-Becker
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Ning Huang
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Tao Sun
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Yuxiang Xie
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Xiu-Tang Cheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Mei-Yao Lin
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Frances M Platt
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA.
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4
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Sakamoto K, Kitano T, Kuwahara H, Tedani M, Aburai K, Futaki S, Abe M, Sakai H, Ohtaka H, Yamashita Y. Effect of Vesicle Size on the Cytolysis of Cell-Penetrating Peptides (CPPs). Int J Mol Sci 2020; 21:E7405. [PMID: 33036492 PMCID: PMC7582850 DOI: 10.3390/ijms21197405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/20/2020] [Accepted: 10/05/2020] [Indexed: 12/29/2022] Open
Abstract
A specific series of peptides, called a cell-penetrating peptide (CPP), is known to be free to directly permeate through cell membranes into the cytosol (cytolysis); hence, this CPP would be a potent carrier for a drug delivery system (DDS). Previously, we proposed the mechanism of cytolysis as a temporal and local phase transfer of membrane lipid caused by positive membrane curvature generation. Moreover, we showed how to control the CPP cytolysis. Here, we investigate the phospholipid vesicle's size effect on CPP cytolysis because this is the most straightforward way to control membrane curvature. Contrary to our expectation, we found that the smaller the vesicle diameter (meaning a higher membrane curvature), the more cytolysis was suppressed. Such controversial findings led us to seek the reason for the unexpected results, and we ended up finding out that the mobility of membrane lipids as a liquid crystal is the key to cytolysis. As a result, we could explain the cause of cytolysis suppression by reducing the vesicle size (because of the restriction of lipid mobility); osmotic pressure reduction to enhance positive curvature generation works as long as the membrane is mobile enough to modulate the local structure. Taking all the revealed vital factors and their effects as a tool, we will further explore how to control CPP cytolysis for developing a DDS system combined with appropriate cargo selection to be tagged with CPPs.
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Affiliation(s)
- Kazutami Sakamoto
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Takeshi Kitano
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Haruka Kuwahara
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Megumi Tedani
- Chiba Institute of Science, Choshi, Chiba 288-0025, Japan; (M.T.); (H.O.); (Y.Y.)
| | - Kenichi Aburai
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan;
| | - Masahiko Abe
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Hideki Sakai
- Tokyo University of Science, Noda, Chiba 278-8510, Japan; (T.K.); (H.K.); (K.A.); (M.A.); (H.S.)
| | - Hiroyasu Ohtaka
- Chiba Institute of Science, Choshi, Chiba 288-0025, Japan; (M.T.); (H.O.); (Y.Y.)
| | - Yuji Yamashita
- Chiba Institute of Science, Choshi, Chiba 288-0025, Japan; (M.T.); (H.O.); (Y.Y.)
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5
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Carter SD, Hampton CM, Langlois R, Melero R, Farino ZJ, Calderon MJ, Li W, Wallace CT, Tran NH, Grassucci RA, Siegmund SE, Pemberton J, Morgenstern TJ, Eisenman L, Aguilar JI, Greenberg NL, Levy ES, Yi E, Mitchell WG, Rice WJ, Wigge C, Pilli J, George EW, Aslanoglou D, Courel M, Freyberg RJ, Javitch JA, Wills ZP, Area-Gomez E, Shiva S, Bartolini F, Volchuk A, Murray SA, Aridor M, Fish KN, Walter P, Balla T, Fass D, Wolf SG, Watkins SC, Carazo JM, Jensen GJ, Frank J, Freyberg Z. Ribosome-associated vesicles: A dynamic subcompartment of the endoplasmic reticulum in secretory cells. Sci Adv 2020; 6:eaay9572. [PMID: 32270040 PMCID: PMC7112762 DOI: 10.1126/sciadv.aay9572] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/13/2020] [Indexed: 05/21/2023]
Abstract
The endoplasmic reticulum (ER) is a highly dynamic network of membranes. Here, we combine live-cell microscopy with in situ cryo-electron tomography to directly visualize ER dynamics in several secretory cell types including pancreatic β-cells and neurons under near-native conditions. Using these imaging approaches, we identify a novel, mobile form of ER, ribosome-associated vesicles (RAVs), found primarily in the cell periphery, which is conserved across different cell types and species. We show that RAVs exist as distinct, highly dynamic structures separate from the intact ER reticular architecture that interact with mitochondria via direct intermembrane contacts. These findings describe a new ER subcompartment within cells.
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Affiliation(s)
- Stephen D. Carter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Cheri M. Hampton
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Robert Langlois
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Roberto Melero
- Biocomputing Unit, Centro Nacional de Biotecnología–CSIC, Darwin 3, Campus Universidad Autónoma, 28049 Madrid, Spain
| | - Zachary J. Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Michael J. Calderon
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Wen Li
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Callen T. Wallace
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Ngoc Han Tran
- HHMI, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Robert A. Grassucci
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Stephanie E. Siegmund
- Department of Cellular, Molecular and Biophysical Studies, Columbia University Medical Center, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Travis J. Morgenstern
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Leanna Eisenman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jenny I. Aguilar
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Nili L. Greenberg
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Elana S. Levy
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Edward Yi
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - William G. Mitchell
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | | | | | - Jyotsna Pilli
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Emily W. George
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Despoina Aslanoglou
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Maïté Courel
- CNRS-UMR7622, Institut de Biologie Paris-Seine, Université Pierre & Marie Curie, 75252 Paris, France
| | - Robin J. Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jonathan A. Javitch
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Zachary P. Wills
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Estela Area-Gomez
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Francesca Bartolini
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Allen Volchuk
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sandra A. Murray
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Meir Aridor
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Kenneth N. Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Peter Walter
- HHMI, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Deborah Fass
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Sharon G. Wolf
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Simon C. Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - José María Carazo
- Biocomputing Unit, Centro Nacional de Biotecnología–CSIC, Darwin 3, Campus Universidad Autónoma, 28049 Madrid, Spain
| | - Grant J. Jensen
- HHMI, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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6
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Nimpf S, Malkemper EP, Lauwers M, Ushakova L, Nordmann G, Wenninger-Weinzierl A, Burkard TR, Jacob S, Heuser T, Resch GP, Keays DA. Subcellular analysis of pigeon hair cells implicates vesicular trafficking in cuticulosome formation and maintenance. eLife 2017; 6:e29959. [PMID: 29140244 PMCID: PMC5699870 DOI: 10.7554/elife.29959] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 06/27/2017] [Accepted: 11/11/2017] [Indexed: 11/13/2022] Open
Abstract
Hair cells are specialized sensors located in the inner ear that enable the transduction of sound, motion, and gravity into neuronal impulses. In birds some hair cells contain an iron-rich organelle, the cuticulosome, that has been implicated in the magnetic sense. Here, we exploit histological, transcriptomic, and tomographic methods to investigate the development of cuticulosomes, as well as the molecular and subcellular architecture of cuticulosome positive hair cells. We show that this organelle forms rapidly after hatching in a process that involves vesicle fusion and nucleation of ferritin nanoparticles. We further report that transcripts involved in endocytosis, extracellular exosomes, and metal ion binding are differentially expressed in cuticulosome positive hair cells. These data suggest that the cuticulosome and the associated molecular machinery regulate the concentration of iron within the labyrinth of the inner ear, which might indirectly tune a magnetic sensor that relies on electromagnetic induction.
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Affiliation(s)
- Simon Nimpf
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
| | | | - Mattias Lauwers
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
| | - Lyubov Ushakova
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
| | - Gregory Nordmann
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
| | | | - Thomas R Burkard
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
| | - Sonja Jacob
- Electron Microscopy FacilityVienna BioCenter Core Facilities GmbHViennaAustria
| | - Thomas Heuser
- Electron Microscopy FacilityVienna BioCenter Core Facilities GmbHViennaAustria
| | | | - David A Keays
- Research Institute of Molecular PathologyVienna BiocenterViennaAustria
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7
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Verdeny-Vilanova I, Wehnekamp F, Mohan N, Sandoval Álvarez Á, Borbely JS, Otterstrom JJ, Lamb DC, Lakadamyali M. 3D motion of vesicles along microtubules helps them to circumvent obstacles in cells. J Cell Sci 2017; 130:1904-1916. [PMID: 28420672 PMCID: PMC5482975 DOI: 10.1242/jcs.201178] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/11/2017] [Indexed: 01/15/2023] Open
Abstract
Vesicle transport is regulated at multiple levels, including regulation by scaffolding proteins and the cytoskeleton. This tight regulation is essential, since slowing or stoppage of transport can cause accumulation of obstacles and has been linked to diseases. Understanding the mechanisms by which transport is regulated as well as how motor proteins overcome obstacles can give important clues as to how these mechanisms break down in disease states. Here, we describe that the cytoskeleton architecture impacts transport in a vesicle-size-dependent manner, leading to pausing of vesicles larger than the separation of the microtubules. We further develop methods capable of following 3D transport processes in living cells. Using these methods, we show that vesicles move using two different modes along the microtubule. Off-axis motion, which leads to repositioning of the vesicle in 3D along the microtubule, correlates with the presence of steric obstacles and may help in circumventing them.
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Affiliation(s)
- Ione Verdeny-Vilanova
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Fabian Wehnekamp
- Ludwig-Maximilians-Universität München, Department of Chemistry, Physical Chemistry, Center for Integrated Protein Science Munich, and Nanosystems Initiative Munich, Butenandtstr. 5-13, München 81377, Germany
| | - Nitin Mohan
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Ángel Sandoval Álvarez
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Joseph Steven Borbely
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Jason John Otterstrom
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Don C Lamb
- Ludwig-Maximilians-Universität München, Department of Chemistry, Physical Chemistry, Center for Integrated Protein Science Munich, and Nanosystems Initiative Munich, Butenandtstr. 5-13, München 81377, Germany
| | - Melike Lakadamyali
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
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8
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Zhang LW, Zeng L, Barron AR, Monteiro-Riviere NA. Biological Interactions of Functionalized Single-Wall Carbon Nanotubes in Human Epidermal Keratinocytes. Int J Toxicol 2016; 26:103-13. [PMID: 17454250 DOI: 10.1080/10915810701225133] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [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: 10/23/2022]
Abstract
Carbon nanotube–based nanovectors, especially functionalized nanotubes, have shown potential for therapeutic drug delivery. 6-Aminohexanoic acid–derivatized single-wall carbon nanotubes (AHA-SWNTs) are soluble in aqueous stock solutions over a wide range of physiologically relevant conditions; however, their interactions with cells and their biological compatibility has not been explored. Human epidermal keratinocytes (HEKs) were dosed with AHA-SWNTs ranging in concentration from 0.00000005 to 0.05 mg/ml. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability decreased significantly ( p < .05) from 0.00005 to 0.05 mg/ml after 24 h. The proinflammatory mediators of inflammation cytokines interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)- α, IL-10, and IL-1 β were also assessed. Cytokine analysis did not show a significant increase in IL-6 and IL-8 in the medium containing 0.000005 mg/ml of AHA-SWNTs from 1 to 48 h. IL-6 increased in cells treated with 0.05 mg/ml of AHA-SWNTs from 1 to 48 h, whereas IL-8 showed a significant increase at 24 and 48 h. No significant difference ( p < .05) was noted with TNF- α, IL-10, and IL-1 β expression at any time point. Transmission electron microscopy of HEKs treated with 0.05 mg/ml AHA-SWNTs for 24 h depicted AHA-SWNTs localized within intracytoplasmic vacuoles in HEKs. Treatment with the surfactant 1% Pluronic F127 caused dispersion of the AHA-SWNT aggregates in the culture medium and less toxicity. These data showed that the lower concentration of 0.000005 mg/ml of AHA-SWNTs maintains cell viability and induces a mild cytotoxicity, but 0.05 mg/ml of AHA-SWNTs demonstrated an irritation response by the increase in IL-8.
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Affiliation(s)
- Leshuai W Zhang
- Center for Chemical Toxicology Research and Pharmacokinetics, North Carolina State University, Raleigh, North Carolina 27606, USA
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9
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Shemi A, Schatz D, Fredricks HF, Van Mooy BAS, Porat Z, Vardi A. Phosphorus starvation induces membrane remodeling and recycling in Emiliania huxleyi. New Phytol 2016; 211:886-898. [PMID: 27111716 DOI: 10.1111/nph.13940] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
Nutrient availability is an important factor controlling phytoplankton productivity. Phytoplankton contribute c. 50% of the global photosynthesis and possess efficient acclimation mechanisms to cope with nutrient stress. We investigate the cellular response of the bloom-forming coccolithophore Emiliania huxleyi to phosphorus (P) scarcity, which is often a limiting factor in marine ecosystems. We combined mass spectrometry, fluorescence microscopy, transmission electron microscopy (TEM) and gene expression analyses in order to assess diverse cellular features in cells exposed to P limitation and recovery. Early starvation-induced substitution of phospholipids in the cells' membranes with galacto- and betaine lipids. Lipid remodeling was rapid and reversible upon P resupply. The PI3K inhibitor wortmannin reduced phospholipid substitution, suggesting a possible involvement of PI3K- signaling in this process. In addition, P limitation enhanced the formation and acidification of membrane vesicles in the cytoplasm. Intracellular vesicles may facilitate the recycling of cytoplasmic content, which is engulfed in the vesicles and delivered to the main vacuole. Long-term starvation was characterized by a profound increase in cell size and morphological alterations in cellular ultrastructure. This study provides cellular and molecular basis for future ecophysiological assessment of natural E. huxleyi populations in oligotrophic regions.
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Affiliation(s)
- Adva Shemi
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Daniella Schatz
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Helen F Fredricks
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Benjamin A S Van Mooy
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Ziv Porat
- Biological Services Department, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, 7610001, Israel
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10
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Abstract
Alveolar soft part sarcoma (ASPS) is a rare neoplasm that most commonly presents in the lower extremities. Although ASPS has distinctive histologic features, it may cause diagnostic problems when it arises in unusual locations. To our knowledge, only 1 case of ASPS arising within the breast has previously been reported. Here, we report a second case of primary mammary ASPS. The patient was a 44-year-old woman who presented with a breast mass. Needle biopsy was performed, yielding a polygonal cell lesion with abundant, predominantly xanthomatous cytoplasm. The cells labeled strongly for the histiocytic marker CD68, suggesting a benign macrophage-rich lesion. However, the unusual nature of the lesion as well as the prominence of nucleoli prompted suggestion for an excision. The excision more clearly revealed the lesion's alveolar architecture and demonstrated cells with more eosinophilic cytoplasm, along with the xanthomatous cells. The diagnosis of ASPS was confirmed by electron microscopy, which revealed characteristic membranebound rhomboidal crystals, as well as by nuclear labeling for TFE3 protein by immunohistochemistry. With this report, we confirm the utility of a novel immunohistochmical technique for the identification of an ASPS presenting in an unusual locale.
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Affiliation(s)
- Julie Wu
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD 21231-2410, USA
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11
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Gotelli MM, Galati BG, Zarlavsky G, Medan D. Pollen and microsporangium development in Hovenia dulcis (Rhamnaceae): a different type of tapetal cell ultrastructure. Protoplasma 2016; 253:1125-33. [PMID: 26277353 DOI: 10.1007/s00709-015-0870-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/08/2015] [Indexed: 05/05/2023]
Abstract
Despite that there is some literature on pollen morphology of Rhamnaceae, studies addressing general aspects of the microsporogenesis, microgametogenesis, and anther development are rare. The aim of this paper is to describe the ultrastructure of pollen grain ontogeny with special attention to tapetum cytology in Hovenia dulcis. Anthers at different stages of development were processed for transmission and scanning electron microscopy, bright-field microscopy, and fluorescence microscopy. Different histochemical reactions were carried out. The ultrastructural changes observed during the development of the tapetal cells and pollen grains are described. Large vesicles containing carbohydrates occur in the tapetal cell cytoplasm during the early stages of pollen development. Its origin and composition are described and discussed. This is the first report on the ontogeny and ultrastructure of the pollen grain and related sporophytic structures of H. dulcis.
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Affiliation(s)
- Marina M Gotelli
- Cátedra de Botánica General, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 (1417), Buenos Aires, Argentina.
- CONICET, Buenos Aires, Argentina.
| | - Beatriz G Galati
- Cátedra de Botánica General, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 (1417), Buenos Aires, Argentina
| | - Gabriela Zarlavsky
- Cátedra de Botánica General, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 (1417), Buenos Aires, Argentina
| | - Diego Medan
- Cátedra de Botánica General, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 (1417), Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
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12
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Rhiel E. On the biogenesis and degradation of ejectisomes in Pyramimonas grossii (Prasinophyceae). Protoplasma 2016; 253:1101-1110. [PMID: 26255174 DOI: 10.1007/s00709-015-0868-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/01/2015] [Indexed: 06/04/2023]
Abstract
The biogenesis, assembly, and degradation of ejectisomes of Pyramimonas grossii were investigated by conventional transmission electron microscopy. Premature ejectisomes were mainly found beneath the cell envelope, often in close proximity to the nucleus, and as vesicles with diameters of 100 to 400 nm. Ejectisomes in the early stages of development contained only a few (2-4) turns of the ejectisome tapes. In the course of the ejectisome development, the number of turns and the widths of the coiled tapes increased. It is likely that vesicles, which were up to 650 nm in diameter, with granule- and plate-like structures inside, delivered additional preassembled ejectisome polypeptides to these premature stages. Both types of vesicles, those containing early stages of ejectisomes and those delivering additional ejectisome material, are believed to originate directly from the endoplasmic reticulum. Mature ejectisomes were mainly registered at the apical periphery of the cells. Up to 11 ejectisomes were found within a single cell. Ejectisomes that were most likely being in the process of degradation were registered within the cytoplasm and within vesicles, often together with material which resembled body scales. Mature ejectisomes which were still furled or which were arrested in the process of discharge were also found outside the cells in the medium.
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Affiliation(s)
- Erhard Rhiel
- Planktologie, ICBM, Carl-von-Ossietzky-Universität Oldenburg, P.O.B. 2503, D-26129, Oldenburg, Germany.
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13
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den Hollander L, Han H, de Winter M, Svensson L, Masich S, Daneholt B, Norlén L. Skin Lamellar Bodies are not Discrete Vesicles but Part of a Tubuloreticular Network. Acta Derm Venereol 2016; 96:303-8. [PMID: 26439096 DOI: 10.2340/00015555-2249] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Improved knowledge of the topology of lamellar bodies is a prerequisite for a molecular-level understanding of skin barrier formation, which in turn may provide clues as to the underlying causes of barrier-deficient skin disease. The aim of this study was to examine the key question of continuity vs. discreteness of the lamellar body system using 3 highly specialized and complementary 3-dimensional (3D) electron microscopy methodologies; tomography of vitreous sections (TOVIS), freeze-substitution serial section electron tomography (FS-SET), and focused ion beam scanning electron microscopy (FIB-SEM) tomography. We present here direct evidence that lamellar bodies are not discrete vesicles, but are part of a tubuloreticular membrane network filling out the cytoplasm and being continuous with the plasma membrane of stratum granulosum cells. This implies that skin barrier formation could be regarded as a membrane folding/unfolding process, but not as a lamellar body fusion process.
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Affiliation(s)
- Lianne den Hollander
- Department of Cell and Molelcular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
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14
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Liu J, Liu W, Yang J. ATP-containing vesicles in stria vascular marginal cell cytoplasms in neonatal rat cochlea are lysosomes. Sci Rep 2016; 6:20903. [PMID: 26864824 PMCID: PMC4750035 DOI: 10.1038/srep20903] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 01/13/2016] [Indexed: 01/03/2023] Open
Abstract
We confirmed that ATP is released from cochlear marginal cells in the stria vascular but the cell organelle in which ATP stores was not identified until now. Thus, we studied the ATP-containing cell organelles and suggest that these are lysosomes. Primary cultures of marginal cells of Sprague-Dawley rats aged 1-3 days was established. Vesicles within marginal cells stained with markers were identified under confocal laser scanning microscope and transmission electron microscope (TEM). Then ATP release from marginal cells was measured after glycyl-L-phenylalanine-ß- naphthylamide (GPN) treatment using a bioluminescent assay. Quinacrine-stained granules within marginal cells were labeled with LysoTracker, a lysosome tracer, and lysosomal-associated membrane protein 1(LAMP1), but not labeled with the mitochondrial tracer MitoTracker. Furthermore, LysoTracker-labelled puncta showed accumulation of Mant-ATP, an ATP analog. Treatment with 200 μM GPN quenched fluorescently labeled puncta after incubation with LysoTracker or quinacrine, but not MitoTracker. Quinacrine-labeled organelles observed by TEM were lysosomes, and an average 27.7 percent increase in ATP luminescence was observed in marginal cells extracellular fluid after GPN treatment. ATP-containing vesicles in cochlear marginal cells of the stria vascular from neonatal rats are likely lysosomes. ATP release from marginal cells may be via Ca(2+)-dependent lysosomal exocytosis.
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Affiliation(s)
- Jun Liu
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, China
- Department of Otorhinolaryngology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenjing Liu
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, China
| | - Jun Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, China
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15
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Harding CR, Egarter S, Gow M, Jiménez-Ruiz E, Ferguson DJP, Meissner M. Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii. PLoS Pathog 2016; 12:e1005403. [PMID: 26845335 PMCID: PMC4742064 DOI: 10.1371/journal.ppat.1005403] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/24/2015] [Indexed: 11/18/2022] Open
Abstract
The inner membrane complex (IMC) of apicomplexan parasites is a specialised structure localised beneath the parasite’s plasma membrane, and is important for parasite stability and intracellular replication. Furthermore, it serves as an anchor for the myosin A motor complex, termed the glideosome. While the role of this protein complex in parasite motility and host cell invasion has been well described, additional roles during the asexual life cycle are unknown. Here, we demonstrate that core elements of the glideosome, the gliding associated proteins GAP40 and GAP50 as well as members of the GAPM family, have critical roles in the biogenesis of the IMC during intracellular replication. Deletion or disruption of these genes resulted in the rapid collapse of developing parasites after initiation of the cell cycle and led to redistribution of other glideosome components. Toxoplasma gondii is an important parasite of humans and animals that must actively invade host cells in order to replicate. Beneath the surface of the parasite lies the inner membrane complex (IMC) which is important in maintaining the stability of the parasite, as well as acting as a base for a protein complex known as the glideosome. This assembly of proteins has an important role in allowing the parasite to invade host cells. Here, we examined the function of proteins known to be part of the glideosome, GAP40, GAP50 and five proteins of the GAPM family. We found that in the absence of GAP40 or GAP50, the parasite is able to start replication but is unable to complete it, suggesting that these proteins have a structural role in maintaining the stability of the developing IMC during replication. We also saw that disruption of some members of the GAPM protein family led to a loss of parasite structure. Our study demonstrates that some components of the glideosome have multiple roles in T. gondii biology and gives us new insights into how cells are constructed during parasite replication.
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Affiliation(s)
- Clare R. Harding
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (CRH); (MM)
| | - Saskia Egarter
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew Gow
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Elena Jiménez-Ruiz
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David J. P. Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, Oxford, United Kingdom
| | - Markus Meissner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (CRH); (MM)
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16
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Rossignol ED, Yang JE, Bullitt E. The Role of Electron Microscopy in Studying the Continuum of Changes in Membranous Structures during Poliovirus Infection. Viruses 2015; 7:5305-18. [PMID: 26473912 PMCID: PMC4632382 DOI: 10.3390/v7102874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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: 07/02/2015] [Revised: 09/01/2015] [Accepted: 09/23/2015] [Indexed: 12/26/2022] Open
Abstract
Replication of the poliovirus genome is localized to cytoplasmic replication factories that are fashioned out of a mixture of viral proteins, scavenged cellular components, and new components that are synthesized within the cell due to viral manipulation/up-regulation of protein and phospholipid synthesis. These membranous replication factories are quite complex, and include markers from multiple cytoplasmic cellular organelles. This review focuses on the role of electron microscopy in advancing our understanding of poliovirus RNA replication factories. Structural data from the literature provide the basis for interpreting a wide range of biochemical studies that have been published on virus-induced lipid biosynthesis. In combination, structural and biochemical experiments elucidate the dramatic membrane remodeling that is a hallmark of poliovirus infection. Temporal and spatial membrane modifications throughout the infection cycle are discussed. Early electron microscopy studies of morphological changes following viral infection are re-considered in light of more recent data on viral manipulation of lipid and protein biosynthesis. These data suggest the existence of distinct subcellular vesicle populations, each of which serves specialized roles in poliovirus replication processes.
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Affiliation(s)
- Evan D Rossignol
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
| | - Jie E Yang
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
| | - Esther Bullitt
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
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17
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Kamdee C, Kirasak K, Ketsa S, van Doorn WG. Vesicles between plasma membrane and cell wall prior to visible senescence of Iris and Dendrobium flowers. J Plant Physiol 2015; 188:37-43. [PMID: 26454639 DOI: 10.1016/j.jplph.2015.02.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/02/2015] [Accepted: 02/25/2015] [Indexed: 05/28/2023]
Abstract
Cut Iris flowers (Iris x hollandica, cv. Blue Magic) show visible senescence about two days after full opening. Epidermal cells of the outer tepals collapse due to programmed cell death (PCD). Transmission electron microscopy (TEM) showed irregular swelling of the cell walls, starting prior to cell collapse. Compared to cells in flowers that had just opened, wall thickness increased up to tenfold prior to cell death. Fibrils were visible in the swollen walls. After cell death very little of the cell wall remained. Prior to and during visible wall swelling, vesicles (paramural bodies) were observed between the plasma membrane and the cell walls. The vesicles were also found in groups and were accompanied by amorphous substance. They usually showed a single membrane, and had a variety of diameters and electron densities. Cut Dendrobium hybrid cv. Lucky Duan flowers exhibited visible senescence about 14 days after full flower opening. Paramural bodies were also found in Dendrobium tepal epidermis and mesophyll cells, related to wall swelling and degradation. Although alternative explanations are well possible, it is hypothesized that paramural bodies carry enzymes involved in cell wall breakdown. The literature has not yet reported such bodies in association with senescence/PCD.
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Affiliation(s)
- Channatika Kamdee
- Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand
| | - Kanjana Kirasak
- Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand
| | - Saichol Ketsa
- Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand; Academy of Science, The Royal Society, Dusit, Bangkok 10300, Thailand.
| | - Wouter G van Doorn
- Mann Laboratory, Department of Plant Sciences, University of California, Davis, CA 95616, USA
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18
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Gaget V, Welker M, Rippka R, de Marsac NT. A polyphasic approach leading to the revision of the genus Planktothrix (Cyanobacteria) and its type species, P. agardhii, and proposal for integrating the emended valid botanical taxa, as well as three new species, Planktothrix paucivesiculata sp. nov.ICNP, Planktothrix tepida sp. nov.ICNP, and Planktothrix serta sp. nov.ICNP, as genus and species names with nomenclatural standing under the ICNP. Syst Appl Microbiol 2015; 38:141-58. [PMID: 25757799 DOI: 10.1016/j.syapm.2015.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/10/2015] [Accepted: 02/13/2015] [Indexed: 10/23/2022]
Abstract
Twenty strains of Planktothrix and five of 'Oscillatoria' were characterized by a polyphasic approach, for clarification of their taxonomic relationships. Emphasis was given to the strains (17) of the Pasteur Culture Collection of Cyanobacteria (PCC). Phenotypic characters analyzed comprised morphology, phycobiliprotein composition, temperature and salinity tolerance. The gvpA gas vesicle gene was detected by PCR in all strains, and transmission electron microscopy confirmed gas vesicle formation in the strains of 'Oscillatoria'. MALDI-TOF mass spectrometry revealed 13 chemotypes, nine of which produce microcystins. A multi-locus sequence typing (MLST) analysis was conducted using individual and concatenated nucleotide sequences of the 16S rDNA, internal transcribed spacer (ITS), gyrB, rpoC1 and rpoB. The results highlighted an unexpected diversity within the genus Planktothrix, showing that the five strains of 'Oscillatoria' need to be included in this taxon. Consequently, the genus consists of seven phylogenetic clusters, three of which represent new species, named Planktothrix paucivesiculata sp. nov.ICNP (type strain: PCC 8926T), Planktothrix tepida sp. nov.ICNP (type strain: PCC 9214T) and Planktothrix serta sp. nov.ICNP (type strain: PCC 8927T). These, together with the emended genus Planktothrix and its type species P. agardhii, valid taxa under the ICN, are described/re-described for gaining nomenclatural standing under the ICNP.
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MESH Headings
- Cluster Analysis
- Cyanobacteria/classification
- Cyanobacteria/cytology
- Cyanobacteria/genetics
- Cyanobacteria/physiology
- Cytoplasmic Vesicles/ultrastructure
- DNA Gyrase/genetics
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/chemistry
- DNA, Ribosomal Spacer/genetics
- DNA-Directed RNA Polymerases/genetics
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Multilocus Sequence Typing
- Phycobiliproteins/analysis
- Phylogeny
- RNA, Ribosomal, 16S/genetics
- Salinity
- Sequence Analysis, DNA
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Temperature
- Terminology as Topic
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Affiliation(s)
- Virginie Gaget
- Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France; Centre d'Analyse Environnementales, Bât. Dufy, 1 place de Turenne, 94417 Saint-Maurice Cedex, France.
| | - Martin Welker
- AnagnosTec GmbH, Am Mühlenberg 11, 14476 Potsdam-Golm, Germany
| | - Rosmarie Rippka
- Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France
| | - Nicole Tandeau de Marsac
- Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France
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19
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Bianchi V, Macchiarelli G, Borini A, Lappi M, Cecconi S, Miglietta S, Familiari G, Nottola SA. Fine morphological assessment of quality of human mature oocytes after slow freezing or vitrification with a closed device: a comparative analysis. Reprod Biol Endocrinol 2014; 12:110. [PMID: 25421073 PMCID: PMC4255960 DOI: 10.1186/1477-7827-12-110] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/14/2014] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Human mature oocytes are very susceptible to cryodamage. Several reports demonstrated that vitrification might preserve oocyte better than slow freezing. However, this is still controversial. Thus, larger clinical, biological and experimental trials to confirm this concept are necessary. The aim of the study was to evaluate and compare fine morphological features in human mature oocytes cryopreserved with either slow freezing or vitrification. METHODS We used 47 supernumerary human mature (metaphase II) oocytes donated by consenting patients, aged 27-32 years, enrolled in an IVF program. Thirtyfive oocytes were cryopreserved using slow freezing with 1.5 M propanediol +0.2 M sucrose concentration (20 oocytes) or a closed vitrification system (CryoTip Irvine Scientific CA) (15 oocytes). Twelve fresh oocytes were used as controls. All samples were prepared for light and transmission electron microscopy evaluation. RESULTS Control, slow frozen/thawed and vitrified/warmed oocytes (CO, SFO and VO, respectively) were rounded, 90-100 μm in diameter, with normal ooplasm showing uniform distribution of organelles. Mitochondria-smooth endoplasmic reticulum (M-SER) aggregates and small mitochondria-vesicle (MV) complexes were the most numerous structures found in all CO, SFO and VO cultured for 3-4 hours. M-SER aggregates decreased, and large MV complexes increased in those SFO and VO maintained in culture for a prolonged period of time (8-9 hours). A slight to moderate vacuolization was present in the cytoplasm of SFO. Only a slight vacuolization was present in VO, whereas vacuoles were almost completely absent in CO. Amount and density of cortical granules (CG) appeared abnormally reduced in SFO and VO, irrespective of the protocol applied. CONCLUSIONS Even though, both slow freezing and vitrification ensured a good overall preservation of the oocyte, we found that: 1) prolonged culture activates an intracellular membrane "recycling" that causes the abnormal transformation of the membranes of the small MV complexes and of SER into larger rounded vesicles; 2) vacuolization appears as a recurrent form of cell damage during slow freezing and, at a lesser extent, during vitrification using a closed device; 3) premature CG exocytosis was present in both SFO and VO and may cause zona pellucida hardening.
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Affiliation(s)
- Veronica Bianchi
- Casa di Cura Città di Udine, Udine, Italy, affiliated to Tecnobios Procreazione, Centre for Reproductive Health, Bologna, Italy
| | - Guido Macchiarelli
- Department of Life, Health and Environmental Sciences, University of L´Aquila, L’Aquila, Italy
| | - Andrea Borini
- Casa di Cura Città di Udine, Udine, Italy, affiliated to Tecnobios Procreazione, Centre for Reproductive Health, Bologna, Italy
| | - Michela Lappi
- Casa di Cura Città di Udine, Udine, Italy, affiliated to Tecnobios Procreazione, Centre for Reproductive Health, Bologna, Italy
| | - Sandra Cecconi
- Department of Life, Health and Environmental Sciences, University of L´Aquila, L’Aquila, Italy
| | - Selenia Miglietta
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, La Sapienza University, Rome, Italy
| | - Giuseppe Familiari
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, La Sapienza University, Rome, Italy
| | - Stefania A Nottola
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, La Sapienza University, Rome, Italy
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Al-Dossary AA, Strehler EE, Martin-DeLeon PA. Expression and secretion of plasma membrane Ca2+-ATPase 4a (PMCA4a) during murine estrus: association with oviductal exosomes and uptake in sperm. PLoS One 2013; 8:e80181. [PMID: 24244642 PMCID: PMC3828235 DOI: 10.1371/journal.pone.0080181] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/09/2013] [Indexed: 12/02/2022] Open
Abstract
PMCA4, a membrane protein, is the major Ca2+ efflux pump in murine sperm where its deletion leads to a severe loss of hyperactivated motility and to male infertility. We have previously shown that the PMCA4b splice variant interacts with CASK (Ca2+/CaM-dependent serine kinase) in regulating sperm Ca2+. More recently we detected that PMCA4a isoform, in addition to its presence in testis, is secreted in the epididymal luminal fluid and transferred to sperm. Here we show that Pmca4 mRNA is expressed in both the 4a and 4b variants in the vagina, uterus, and oviduct. Immunofluorescence reveals that PMCA4a is similarly expressed and is elevated during estrus, appearing in the glandular and luminal epithelia. Western analysis detected PMCA4a in all tissues and in the luminal fluids (LF) of the vagina (VLF), uterus (ULF), and the oviduct (OLF) collected during estrus. It was ~9- and 4-fold higher in OLF than in VLF and ULF, and only marginally present in LF collected at metestrus/diestrus. Fractionation of the LF collected at estrus, via ultracentrifugation, revealed that 100% of the PMCA4a resides in the vesicular fraction of the ULF and OLF. Transmission electron microscopy (TEM) revealed that OLF vesicles have an exosomal orientation (with the cytoplasmic-side inward), a size range of 25-100 nm, with the characteristic CD9 biomarker. Thus, we dubbed these vesicles “oviductosomes”, to which PMCA4a was immunolocalized. Incubation of caudal sperm in the combined LF or exosomes resulted in up to a ~3-fold increase of sperm PMCA4a, as detected by flow cytometry, indicating in vitro uptake. Our results are consistent with the increased requirement of Ca2+ efflux in the oviduct. They show for the first time the presence of oviductal exosomes and highlight their role, along with uterosomes and vaginal exosomes, in post-testicular sperm acquisition of PMCA4a which is essential for hyperactivated motility and fertility.
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Affiliation(s)
- Amal A. Al-Dossary
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Emanuel E. Strehler
- Department of Biochemistry, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Patricia A. Martin-DeLeon
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- * E-mail:
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21
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Dragowska WH, Weppler SA, Wang JC, Wong LY, Kapanen AI, Rawji JS, Warburton C, Qadir MA, Donohue E, Roberge M, Gorski SM, Gelmon KA, Bally MB. Induction of autophagy is an early response to gefitinib and a potential therapeutic target in breast cancer. PLoS One 2013; 8:e76503. [PMID: 24146879 PMCID: PMC3795739 DOI: 10.1371/journal.pone.0076503] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/27/2013] [Indexed: 12/14/2022] Open
Abstract
Gefitinib (Iressa(®), ZD1839) is a small molecule inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. We report on an early cellular response to gefitinib that involves induction of functional autophagic flux in phenotypically diverse breast cancer cells that were sensitive (BT474 and SKBR3) or insensitive (MCF7-GFPLC3 and JIMT-1) to gefitinib. Our data show that elevation of autophagy in gefitinib-treated breast cancer cells correlated with downregulation of AKT and ERK1/2 signaling early in the course of treatment. Inhibition of autophagosome formation by BECLIN-1 or ATG7 siRNA in combination with gefitinib reduced the abundance of autophagic organelles and sensitized SKBR3 but not MCF7-GFPLC3 cells to cell death. However, inhibition of the late stage of gefitinib-induced autophagy with hydroxychloroquine (HCQ) or bafilomycin A1 significantly increased (p<0.05) cell death in gefitinib-sensitive SKBR3 and BT474 cells, as well as in gefitinib-insensitive JIMT-1 and MCF7-GFPLC3 cells, relative to the effects observed with the respective single agents. Treatment with the combination of gefitinib and HCQ was more effective (p<0.05) in delaying tumor growth than either monotherapy (p>0.05), when compared to vehicle-treated controls. Our results also show that elevated autophagosome content following short-term treatment with gefitinib is a reversible response that ceases upon removal of the drug. In aggregate, these data demonstrate that elevated autophagic flux is an early response to gefitinib and that targeting EGFR and autophagy should be considered when developing new therapeutic strategies for EGFR expressing breast cancers.
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Affiliation(s)
- Wieslawa H. Dragowska
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Sherry A. Weppler
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jun Chih Wang
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Ling Yan Wong
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Anita I. Kapanen
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Jenna S. Rawji
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Corinna Warburton
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Mohammed A. Qadir
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Elizabeth Donohue
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michel Roberge
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Center for Drug Research and Development, Vancouver, British Columbia, Canada
| | - Sharon M. Gorski
- Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Karen A. Gelmon
- Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marcel B. Bally
- Department of Experimental Therapeutics, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Center for Drug Research and Development, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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22
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Song X, Lichti CF, Townsend RR, Mueckler M. Single point mutations result in the miss-sorting of Glut4 to a novel membrane compartment associated with stress granule proteins. PLoS One 2013; 8:e68516. [PMID: 23874650 PMCID: PMC3713040 DOI: 10.1371/journal.pone.0068516] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 05/29/2013] [Indexed: 01/16/2023] Open
Abstract
Insulin increases cellular glucose uptake and metabolism in the postprandial state by acutely stimulating the translocation of the Glut4 glucose transporter from intracellular membrane compartments to the cell surface in muscle and fat cells. The intracellular targeting of Glut4 is dictated by specific structural motifs within cytoplasmic domains of the transporter. We demonstrate that two leucine residues at the extreme C-terminus of Glut4 are critical components of a motif (IRM, insulin responsive motif) involved in the sorting of the transporter to insulin responsive vesicles in 3T3L1 adipocytes. Light microscopy, immunogold electron microscopy, subcellular fractionation, and sedimentation analysis indicate that mutations in the IRM cause the aberrant targeting of Glut4 to large dispersed membrane vesicles that are not insulin responsive. Proteomic characterization of rapidly and slowly sedimenting membrane vesicles (RSVs and SSVs) that were highly enriched by immunoadsorption for either wild-type Glut4 or an IRM mutant revealed that the major vesicle fraction containing the mutant transporter (IRM-RSVs) possessed a relatively small and highly distinct protein population that was enriched for proteins associated with stress granules. We suggest that the IRM is critical for an early step in the sorting of Glut4 to insulin-responsive subcellular membrane compartments and that IRM mutants are miss-targeted to relatively large, amorphous membrane vesicles that may be involved in a degradation pathway for miss-targeted or miss-folded proteins or represent a transitional membrane compartment that Glut4 traverses en route to insulin responsive storage compartments.
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Affiliation(s)
- XiaoMei Song
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Cheryl F. Lichti
- Department of Pharmacology & Toxicology, University of Texas, Galveston, Texas, United States of America
| | - R. Reid Townsend
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Mike Mueckler
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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23
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New SE, Goettsch C, Aikawa M, Marchini JF, Shibasaki M, Yabusaki K, Libby P, Shanahan CM, Croce K, Aikawa E. Macrophage-derived matrix vesicles: an alternative novel mechanism for microcalcification in atherosclerotic plaques. Circ Res 2013; 113:72-7. [PMID: 23616621 PMCID: PMC3703850 DOI: 10.1161/circresaha.113.301036] [Citation(s) in RCA: 310] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RATIONALE We previously showed that early calcification of atherosclerotic plaques associates with macrophage accumulation. Chronic renal disease and mineral imbalance accelerate calcification and the subsequent release of matrix vesicles (MVs), precursors of microcalcification. OBJECTIVE We tested the hypothesis that macrophage-derived MVs contribute directly to microcalcification. METHODS AND RESULTS Macrophages associated with regions of calcified vesicular structures in human carotid plaques (n=136 patients). In vitro, macrophages released MVs with high calcification and aggregation potential. MVs expressed exosomal markers (CD9 and TSG101) and contained S100A9 and annexin V. Silencing S100A9 in vitro and genetic deficiency in S100A9-/- mice reduced MV calcification, whereas stimulation with S100A9 increased calcification potential. Externalization of phosphatidylserine after Ca/P stimulation and interaction of S100A9 and annexin V indicated that a phosphatidylserine-annexin V-S100A9 membrane complex facilitates hydroxyapatite nucleation within the macrophage-derived MV membrane. CONCLUSIONS Our results support the novel concept that macrophages release calcifying MVs enriched in S100A9 and annexin V, which contribute to accelerated microcalcification in chronic renal disease.
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Affiliation(s)
- Sophie E. New
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Claudia Goettsch
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Masanori Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Cardiovascular Division and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Julio F. Marchini
- Cardiovascular Division and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Manabu Shibasaki
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Katsumi Yabusaki
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Peter Libby
- Cardiovascular Division and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | | | - Kevin Croce
- Cardiovascular Division and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Elena Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Cardiovascular Division and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
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24
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Wu S, Ju GQ, Du T, Zhu YJ, Liu GH. Microvesicles derived from human umbilical cord Wharton's jelly mesenchymal stem cells attenuate bladder tumor cell growth in vitro and in vivo. PLoS One 2013; 8:e61366. [PMID: 23593475 PMCID: PMC3625149 DOI: 10.1371/journal.pone.0061366] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/07/2013] [Indexed: 12/29/2022] Open
Abstract
Several studies suggest that mesenchymal stem cells (MSCs) possess antitumor properties; however, the exact mechanisms remain unclear. Recently, microvesicles (MVs) are considered as a novel avenue intercellular communication, which may be a mediator in MSCs-related antitumor effect. In the present study, we evaluated whether MVs derived from human umbilical cord Wharton's jelly mesenchymal stem cells (hWJMSCs) may inhibit bladder tumor T24 cells growth using cell culture and the BALB/c nu/nu mice xenograft model. CCK-8 assay and Ki-67 immunostaining were performed to estimate cell proliferation in vitro and in vivo. Flow cytometry and TUNEL assay were used to assess cell cycle and apoptosis. To study the conceivable mechanism by which hWJMSC-MVs attenuate bladder tumor T24 cells, we estimated the expression of Akt/p-Akt, p-p53, p21 and cleaved Caspase 3 by Western blot technique after exposing T24 cells to hWJMSC-MVs for 24, 48 and 72h. Our data indicated that hWJMSC-MVs can inhibit T24 cells proliferative viability via cell cycle arrest and induce apoptosis in T24 cells in vitro and in vivo. This study showed that hWJMSC-MVs down-regulated phosphorylation of Akt protein kinase and up-regulated cleaved Caspase 3 during the process of anti-proliferation and pro-apoptosis in T24 cells. These results demonstrate that hWJMSC-MVs play a vital role in hWJMSC-induced antitumor effect and may be a novel tool for cancer therapy as a new mechanism of cell-to-cell communication.
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Affiliation(s)
- Shuai Wu
- Department of Urology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Urology, Qingdao Municipal Hospital, Qingdao, Shandong, China
| | - Guan-Qun Ju
- Department of Urology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Tao Du
- Department of Urology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying-Jian Zhu
- Department of Urology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (YJZ); (GHL)
| | - Guo-Hua Liu
- Department of Urology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (YJZ); (GHL)
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25
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Abstract
In this issue of Microcirculation, Wagner, Modla, Hossler and Czmmek [25] describe the use of electron tomography to visualize the three-dimensional arrangement of small endothelial vesicles and caveolae of muscle capillaries. Their images show the well-known clusters of fused vesicles communicating with caveolae at the luminal and abluminal surfaces. The advantages of electron tomography are shown by well resolved images of single cytoplasmic vesicles separate from fused vesicle clusters and also by occasional chains of fused vesicles forming trans-endothelial channels. Twenty five to thirty years ago the existence of both trans-endothelial channels and single unattached vesicles was disputed. Also, since some single vesicles and all of the trans-endothelial channels are labeled with a lanthanide tracer present in the perfusate at the time of fixation, this evidence once again raises the question of whether vesicles have a role in vascular permeability to macromolecules. This brief review describes the origin of the vesicle controversy, some of the more recent evidence for and against the participation of vesicles in macromolecular transport and considers some criticisms of ultra-structural evidence for vesicular transport that still require answers.
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26
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Boonrungsiman S, Gentleman E, Carzaniga R, Evans ND, McComb DW, Porter AE, Stevens MM. The role of intracellular calcium phosphate in osteoblast-mediated bone apatite formation. Proc Natl Acad Sci U S A 2012; 109:14170-5. [PMID: 22879397 PMCID: PMC3435222 DOI: 10.1073/pnas.1208916109] [Citation(s) in RCA: 334] [Impact Index Per Article: 27.8] [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] [Indexed: 11/18/2022] Open
Abstract
Mineralization is a ubiquitous process in the animal kingdom and is fundamental to human development and health. Dysfunctional or aberrant mineralization leads to a variety of medical problems, and so an understanding of these processes is essential to their mitigation. Osteoblasts create the nano-composite structure of bone by secreting a collagenous extracellular matrix (ECM) on which apatite crystals subsequently form. However, despite their requisite function in building bone and decades of observations describing intracellular calcium phosphate, the precise role osteoblasts play in mediating bone apatite formation remains largely unknown. To better understand the relationship between intracellular and extracellular mineralization, we combined a sample-preparation method that simultaneously preserved mineral, ions, and ECM with nano-analytical electron microscopy techniques to examine osteoblasts in an in vitro model of bone formation. We identified calcium phosphate both within osteoblast mitochondrial granules and intracellular vesicles that transported material to the ECM. Moreover, we observed calcium-containing vesicles conjoining mitochondria, which also contained calcium, suggesting a storage and transport mechanism. Our observations further highlight the important relationship between intracellular calcium phosphate in osteoblasts and their role in mineralizing the ECM. These observations may have important implications in deciphering both how normal bone forms and in understanding pathological mineralization.
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Affiliation(s)
| | - Eileen Gentleman
- Departments of Materials and
- Institute of Biomedical Engineering, and
- Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, United Kingdom; and
| | - Raffaella Carzaniga
- Electron Microscopy Centre, Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Nicholas D. Evans
- Departments of Materials and
- Institute of Biomedical Engineering, and
| | - David W. McComb
- Departments of Materials and
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210
| | | | - Molly M. Stevens
- Departments of Materials and
- Bioengineering
- Institute of Biomedical Engineering, and
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27
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Abstract
The primary function of the urothelium is to provide the tightest and most impermeable barrier in the body, i.e. the blood-urine barrier. Urothelial plaques are formed and inserted into the apical plasma membrane during advanced stages of urothelial cell differentiation. Currently, it is supposed that differentiation with the final formation of urothelial plaques is hindered in cultured urothelial cells. With the aid of the high-resolution imaging technique of freeze-fracture replica immunolabelling, we here provide evidence that urothelial cells in vitro form uroplakin-positive urothelial plaques, localized in fusiform-shaped vesicles and apical plasma membranes. With the establishment of such an in vitro model of urothelial cells with fully developed urothelial plaques and functional properties equivalent to normal bladder urothelium, new perspectives have emerged which challenge prevailing concepts of apical plasma membrane biogenesis and blood-urine barrier development. This may hopefully provide a timely impulse for many ongoing studies and open up new questions for future research.
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Affiliation(s)
- Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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28
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Kononenko NL, Kiss T, Elekes K. The neuroanatomical and ultrastructural organization of statocyst hair cells in the pond snail, Lymnaea stagnalis. Acta Biol Hung 2012; 63 Suppl 1:99-113. [PMID: 22453745 DOI: 10.1556/abiol.63.2012.suppl.1.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 11/19/2022]
Abstract
The ultrastructure, neuroanatomy and central projection patterns, including the intercellular connections of the statocyst hair cells of the pond snail, Lymnaea stagnalis, were studied, applying different intra- and extracellular cellular staining techniques combined with correlative light- and electron microscopy. Based on the ultrastructure different hair cells could be distinguished according to their vesicle and granule content, meanwhile the general organization of the sensory neurons was rather uniform, showing clearly separated perinuclear and "vesicular" cytoplasmic regions. Following intra- and extracellular labeling with fluorescence dyes or HRP a typical, local arborization of the hair cells was demonstrated in the cerebral ganglion neuropil, indicating a limited input-output system connected to the process of gravireception. Correlative light- and electron microscopy of HRP-labeled hair cells revealed both axo-somatic and axo-axonic output contacts of hair cell varicosities, and input on sensory axons located far from the terminal arborizations. Our findings suggest (i) a versatile ultrastructural background of hair cells corresponding possibly to processing different gravireceptive information, and (ii) the synaptic (or non-synaptic) influence of gravireception at different anatomical (terminal, axonal and cell body) levels when processed centrally. The results may also serve as a functional morphological background for previously obtained physiological and behavioral observations.
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Affiliation(s)
- Natalia L Kononenko
- Department of Experimental Zoology, Balaton Limnological Center for Ecological Research Institute, Hungarian Academy of Sciences P.O. Box 35 H-8237 Tihany, Hungary
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29
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Liu WM, Dennis JL, Gravett AM, Chanthirakumar C, Kaminska E, Coulton G, Fowler DW, Bodman-Smith M, Dalgleish AG. Supernatants derived from chemotherapy-treated cancer cell lines can modify angiogenesis. Br J Cancer 2012; 106:896-903. [PMID: 22294186 PMCID: PMC3305950 DOI: 10.1038/bjc.2012.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/21/2011] [Accepted: 01/05/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND There is evidence that tumours produce substances such as cytokines and microvesicular bodies bearing bioactive molecules, which support the carcinogenic process. Furthermore, chemotherapy has also been shown to modify these exudates and in doing so, neutralise their tumourigenic influence. METHODS In the current study, we have investigated the effect of chemotherapy agents on modifying the cytokine profile and microvesicular cargo of supernatants derived from cancer cell lines. In addition, we have explored the effect of these tumour-derived supernatants on angiogenesis, and how chemotherapy can alter the supernatants rendering them less pro-angiogenic. RESULTS Herein, we show that supernatants contain a rich cocktail of cytokines, a number of which are potent modulators of angiogenesis. They also contain microvesicular bodies containing RNA transcripts that code for proteins involved in transcription, immune modulation and angiogenesis. These supernatants altered intracellular signalling molecules in endothelial cells and significantly enhanced their tubulogenic character; however, this was severely compromised when supernatants from tumours treated with chemotherapy was used instead. CONCLUSION This study suggests tumour exudates and bioactive material from tumours can influence cellular functions, and that treatment with some chemotherapy can serve to negate these pro-tumourigenic processes.
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Affiliation(s)
- W M Liu
- Department of Oncology, Division of Clinical Sciences, St George's, University of London, London SW17 0RE, UK.
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30
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Wu YY, Ye XJ. [Roles of microvesicles in tumor progress and its clinical application]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2012; 41:105-110. [PMID: 22419473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microvesicles transport special proteins, micro RNA and DNA segments, which provides new access to intercellular communication. Tumor-derived membrane microvesicles (TMV) are involved in the tumor progress by transporting tumor-derived proteins, delivering microRNA to surrounding normal cells to alter their phenotype and promoting reverse transcription to interfere gene stability and to create tumor microenvironment. TMV also play crucial roles in tumor angiogenesis and matrix degradation, which facilitates malignant cell metastasis. TMVs are also involved in escaping immunological surveillance by intensifying the function of suppressor T cell and inducing apoptosis of cytotoxic T cells. On the other hand, microvesicles carry tumor antigens and can be used for development of tumor vaccines; some new vaccines such as AEX and DEX are under early clinical trials. Circulating microRNA and DNA segments in body fluid can be a new potential biomarker for cancer diagnosis and prognosis. Purification of microvesicles needs to be further improved, which is important for identification of microvesicles and their subtypes.
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Affiliation(s)
- Ying-ying Wu
- Center of Bone Marrow Ttransplantation, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
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31
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Šuštar V, Bedina-Zavec A, Štukelj R, Frank M, Bobojević G, Janša R, Ogorevc E, Kruljc P, Mam K, Šimunič B, Manček-Keber M, Jerala R, Rozman B, Veranič P, Hägerstrand H, Kralj-Iglič V. Nanoparticles isolated from blood: a reflection of vesiculability of blood cells during the isolation process. Int J Nanomedicine 2011; 6:2737-48. [PMID: 22128248 PMCID: PMC3225219 DOI: 10.2147/ijn.s24537] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Shedding of nanoparticles from the cell membrane is a common process in all cells. These nanoparticles are present in body fluids and can be harvested by isolation. To collect circulating nanoparticles from blood, a standard procedure consisting of repeated centrifugation and washing is applied to the blood samples. Nanoparticles can also be shed from blood cells during the isolation process, so it is unclear whether nanoparticles found in the isolated material are present in blood at sampling or if are they created from the blood cells during the isolation process. We addressed this question by determination of the morphology and identity of nanoparticles harvested from blood. METHODS The isolates were visualized by scanning electron microscopy, analyzed by flow cytometry, and nanoparticle shapes were determined theoretically. RESULTS The average size of nanoparticles was about 300 nm, and numerous residual blood cells were found in the isolates. The shapes of nanoparticles corresponded to the theoretical shapes obtained by minimization of the membrane free energy, indicating that these nanoparticles can be identified as vesicles. The concentration and size of nanoparticles in blood isolates was sensitive to the temperature during isolation. We demonstrated that at lower temperatures, the nanoparticle concentration was higher, while the nanoparticles were on average smaller. CONCLUSION These results indicate that a large pool of nanoparticles is produced after blood sampling. The shapes of deformed blood cells found in the isolates indicate how fragmentation of blood cells may take place. The results show that the contents of isolates reflect the properties of blood cells and their interaction with the surrounding solution (rather than representing only nanoparticles present in blood at sampling) which differ in different diseases and may therefore present a relevant clinical parameter.
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Affiliation(s)
- Vid Šuštar
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Apolonija Bedina-Zavec
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Laboratory of Biosynthesis and Biotransformation, National Institute of Chemistry, Ljubljana, Slovenia
| | - Roman Štukelj
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Mojca Frank
- Department of Rheumatology, Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Goran Bobojević
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Rado Janša
- Department of Gastroenterology, Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Eva Ogorevc
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Kruljc
- Clinics for Reproduction and Horses, Faculty of Veterinary Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Boštjan Šimunič
- Laboratory of Biotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Mateja Manček-Keber
- University of Primorska, Science and Research Centre of Koper, Koper, Slovenia
| | - Roman Jerala
- University of Primorska, Science and Research Centre of Koper, Koper, Slovenia
| | - Blaž Rozman
- Department of Rheumatology, Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Peter Veranič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Henry Hägerstrand
- Department of Biosciences, Biocity, Åbo Akademi University, Åbo/Turku, Finland
| | - Veronika Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Graziano F, Elia C, Laudanna C, Poli G, Alfano M. Urokinase plasminogen activator inhibits HIV virion release from macrophage-differentiated chronically infected cells via activation of RhoA and PKCε. PLoS One 2011; 6:e23674. [PMID: 21858203 PMCID: PMC3157461 DOI: 10.1371/journal.pone.0023674] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 07/25/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND HIV replication in mononuclear phagocytes is a multi-step process regulated by viral and cellular proteins with the peculiar feature of virion budding and accumulation in intra-cytoplasmic vesicles. Interaction of urokinase-type plasminogen activator (uPA) with its cell surface receptor (uPAR) has been shown to favor virion accumulation in such sub-cellular compartment in primary monocyte-derived macrophages and chronically infected promonocytic U1 cells differentiated into macrophage-like cells by stimulation with phorbol myristate acetate (PMA). By adopting this latter model system, we have here investigated which intracellular signaling pathways were triggered by uPA/uPAR interaction leading the redirection of virion accumulation in intra-cytoplasmic vesicles. RESULTS uPA induced activation of RhoA, PKCδ and PKCε in PMA-differentiated U1 cells. In the same conditions, RhoA, PKCδ and PKCε modulated uPA-induced cell adhesion and polarization, whereas only RhoA and PKCε were also responsible for the redirection of virions in intracellular vesicles. Distribution of G and F actin revealed that uPA reorganized the cytoskeleton in both adherent and polarized cells. The role of G and F actin isoforms was unveiled by the use of cytochalasin D, a cell-permeable fungal toxin that prevents F actin polymerization. Receptor-independent cytoskeleton remodeling by Cytochalasin D resulted in cell adhesion, polarization and intracellular accumulation of HIV virions similar to the effects gained with uPA. CONCLUSIONS These findings illustrate the potential contribution of the uPA/uPAR system in the generation and/or maintenance of intra-cytoplasmic vesicles that actively accumulate virions, thus sustaining the presence of HIV reservoirs of macrophage origin. In addition, our observations also provide evidences that pathways controlling cytoskeleton remodeling and activation of PKCε bear relevance for the design of new antiviral strategies aimed at interfering with the partitioning of virion budding between intra-cytoplasmic vesicles and plasma membrane in infected human macrophages.
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Affiliation(s)
- Francesca Graziano
- AIDS Immunophatogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Chiara Elia
- AIDS Immunophatogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Carlo Laudanna
- Department of Pathology & Diagnostic, Faculty of Medicine and Surgery, Verona, Italy
| | - Guido Poli
- AIDS Immunophatogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
| | - Massimo Alfano
- AIDS Immunophatogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
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Cmoch A, Strzelecka-Kiliszek A, Palczewska M, Groves P, Pikula S. Matrix vesicles isolated from mineralization-competent Saos-2 cells are selectively enriched with annexins and S100 proteins. Biochem Biophys Res Commun 2011; 412:683-7. [PMID: 21867690 DOI: 10.1016/j.bbrc.2011.08.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 08/07/2011] [Indexed: 02/06/2023]
Abstract
Matrix vesicles (MVs) are cell-derived membranous entities crucial for mineral formation in the extracellular matrix. One of the dominant groups of constitutive proteins present in MVs, recognised as regulators of mineralization in norm and pathology, are annexins. In this report, besides the annexins already described (AnxA2 and AnxA6), we identified AnxA1 and AnxA7, but not AnxA4, to become selectively enriched in MVs of Saos-2 cells upon stimulation for mineralization. Among them, AnxA6 was found to be almost EGTA-non extractable from matrix vesicles. Moreover, our report provides the first evidence of annexin-binding S100 proteins to be present in MVs of mineralizing cells. We observed that S100A10 and S100A6, but not S100A11, were selectively translocated to the MVs of Saos-2 cells upon mineralization. This observation provides the rationale for more detailed studies on the role of annexin-S100 interactions in MV-mediated mineralization.
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Affiliation(s)
- Anna Cmoch
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
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Boeuf P, Hasang W, Hanssen E, Glazier JD, Rogerson SJ. Relevant assay to study the adhesion of Plasmodium falciparum-infected erythrocytes to the placental epithelium. PLoS One 2011; 6:e21126. [PMID: 21731654 PMCID: PMC3123321 DOI: 10.1371/journal.pone.0021126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/19/2011] [Indexed: 11/26/2022] Open
Abstract
In placental malaria, Plasmodium falciparum-infected erythrocytes adhere to the apical plasma membrane of the placental epithelium, triggering an impairment of placental function detrimental to the fetus. The design of anti-adhesion intervention strategies requires a detailed understanding of the mechanisms involved. However, most adhesion assays lack in vivo relevance and are hardly quantitative. Here, we describe a flow cytometry-based adhesion assay that is fully relevant by using apical epithelial plasma membrane vesicles as the adhesion matrix, and being applicable to infected erythrocytes directly isolated from patients. Adhesion is measured both as the percentage of pathogens bound to epithelial membrane vesicles as well as the mean number of vesicles bound per infected erythrocytes. We show that adhesins alternative to those currently identified could be involved. This demonstrates the power of this assay to advance our understanding of epithelial adhesion of infected erythrocytes and in the design of intervention strategies.
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Affiliation(s)
- Philippe Boeuf
- Department of Medicine (RMH/WH), The University of Melbourne, Royal Melbourne Hospital, Melbourne, Australia.
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35
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Wang X, Wiens M, Schröder HC, Schloßmacher U, Pisignano D, Jochum KP, Müller WEG. Evagination of cells controls bio-silica formation and maturation during spicule formation in sponges. PLoS One 2011; 6:e20523. [PMID: 21655099 PMCID: PMC3107217 DOI: 10.1371/journal.pone.0020523] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/02/2011] [Indexed: 12/04/2022] Open
Abstract
The enzymatic-silicatein mediated formation of the skeletal elements, the spicules of siliceous sponges starts intracellularly and is completed extracellularly. With Suberites domuncula we show that the axial growth of the spicules proceeds in three phases: (I) formation of an axial canal; (II) evagination of a cell process into the axial canal, and (III) assembly of the axial filament composed of silicatein. During these phases the core part of the spicule is synthesized. Silicatein and its substrate silicate are stored in silicasomes, found both inside and outside of the cellular extension within the axial canal, as well as all around the spicule. The membranes of the silicasomes are interspersed by pores of ≈2 nm that are likely associated with aquaporin channels which are implicated in the hardening of the initial bio-silica products formed by silicatein. We can summarize the sequence of events that govern spicule formation as follows: differential genetic readout (of silicatein) → fractal association of the silicateins → evagination of cells by hydro-mechanical forces into the axial canal → and finally processive bio-silica polycondensation around the axial canal. We termed this process, occurring sequentially or in parallel, bio-inorganic self-organization.
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Affiliation(s)
- Xiaohong Wang
- National Research Center for Geoanalysis, Beijing, China
- European Research Council Advanced Grant Research Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Matthias Wiens
- European Research Council Advanced Grant Research Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Heinz C. Schröder
- European Research Council Advanced Grant Research Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Ute Schloßmacher
- European Research Council Advanced Grant Research Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dario Pisignano
- Dipartimento di Ingegneria dell'Innovazione, Università del Salento and National Nanotechnology Laboratory of CNR-Istituto Nanoscienze, Lecce, Italy
| | | | - Werner E. G. Müller
- European Research Council Advanced Grant Research Group, Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- * E-mail:
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Hsu CY, Chan YP. Identification and localization of proteins associated with biomineralization in the iron deposition vesicles of honeybees (Apis mellifera). PLoS One 2011; 6:e19088. [PMID: 21541330 PMCID: PMC3082545 DOI: 10.1371/journal.pone.0019088] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 03/28/2011] [Indexed: 11/18/2022] Open
Abstract
Honeybees (Apis mellifera) form superparamagnetic magnetite to act as a magnetoreceptor for magnetoreception. Biomineralization of superparamagnetic magnetite occurs in the iron deposition vesicles of trophocytes. Even though magnetite has been demonstrated, the mechanism of magnetite biomineralization is unknown. In this study, proteins in the iron granules and iron deposition vesicles of trophocytes were purified and identified by mass spectrometry. Antibodies against such proteins were produced. The major proteins include actin, myosin, ferritin 2, and ATP synthase. Immunolabeling and co-immunoprecipitation studies suggest that iron is stored in ferritin 2 for the purpose of forming 7.5-nm diameter iron particles and that actin-myosin-ferritin 2 may serve as a transporter system. This system, along with calcium and ATP, conveys the iron particles (ferritin) to the center of iron deposition vesicles for iron granules formation. These proteins and reactants are included in iron deposition vesicles during the formation of iron deposition vesicles from the fusion of smooth endoplasmic reticulum. A hypothetical model for magnetite biomineralization in iron deposition vesicles is proposed for honeybees.
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Affiliation(s)
- Chin-Yuan Hsu
- Department of Biomedical Sciences, Chang Gung University, Tao-Yuan, Taiwan. hsu @mail.cgu.edu.tw
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Geppert M, Hohnholt MC, Thiel K, Nürnberger S, Grunwald I, Rezwan K, Dringen R. Uptake of dimercaptosuccinate-coated magnetic iron oxide nanoparticles by cultured brain astrocytes. Nanotechnology 2011; 22:145101. [PMID: 21346306 DOI: 10.1088/0957-4484/22/14/145101] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Magnetic iron oxide nanoparticles (Fe-NP) are currently considered for various diagnostic and therapeutic applications in the brain. However, little is known on the accumulation and biocompatibility of such particles in brain cells. We have synthesized and characterized dimercaptosuccinic acid (DMSA) coated Fe-NP and have investigated their uptake by cultured brain astrocytes. DMSA-coated Fe-NP that were dispersed in physiological medium had an average hydrodynamic diameter of about 60 nm. Incubation of cultured astrocytes with these Fe-NP caused a time- and concentration-dependent accumulation of cellular iron, but did not lead within 6 h to any cell toxicity. After 4 h of incubation with 100-4000 µM iron supplied as Fe-NP, the cellular iron content reached levels between 200 and 2000 nmol mg⁻¹ protein. The cellular iron content after exposure of astrocytes to Fe-NP at 4 °C was drastically lowered compared to cells that had been incubated at 37 °C. Electron microscopy revealed the presence of Fe-NP-containing vesicles in cells that were incubated with Fe-NP at 37 °C, but not in cells exposed to the nanoparticles at 4 °C. These data demonstrate that cultured astrocytes efficiently take up DMSA-coated Fe-NP in a process that appears to be saturable and strongly depends on the incubation temperature.
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Affiliation(s)
- Mark Geppert
- Center for Biomolecular Interactions Bremen, University of Bremen, PO Box 330440, D-28334 Bremen, Germany
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38
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Monteiro O, Wiegand UK, Ludwig M. Vesicle degradation in dendrites of magnocellular neurones of the rat supraoptic nucleus. Neurosci Lett 2011; 489:30-3. [PMID: 21129440 DOI: 10.1016/j.neulet.2010.11.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 11/02/2010] [Accepted: 11/20/2010] [Indexed: 11/17/2022]
Abstract
The magnocellular neurones of the supraoptic nucleus (SON) and paraventricular nucleus release neuropeptide from their axon terminals and also from their dendrites. In the axon terminals, swellings known as Herring bodies are responsible for the degradation of aged, unreleased large dense-cored vesicles (LDCVs) by lysosomes. Dendrites of magnocellular neurones also contain a large number of LDCVs but specialised areas of vesicle degradation have yet to be discovered. Using immunofluorescence labelling for lysosomes in vasopressin-enhanced green fluorescent protein (vasopressin-eGFP) transgenic rats, we found that lysosomes are preferentially located in the centre of the dendrites where there was a high density of vasopressin-eGFP expression. These data suggest that there are local "hot spots", but not specific compartments for vesicle degradation in magnocellular dendrites.
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Affiliation(s)
- Olivia Monteiro
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
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39
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Abstract
High-resolution imaging of the membranous intermediates and cytoskeletal arrays involved in the assembly of a new cell wall during plant cytokinesis requires state-of-the-art electron microscopy techniques. The combination of cryofixation/freeze-substitution methods with electron tomography (ET) has revealed amazing structural details of this unique cellular process. This chapter deals with the main steps associated with these imaging techniques: selection of samples suitable for studying plant cytokinesis, sample preparation by high-pressure freezing/freeze substitution, and ET of plastic sections. In addition, immunogold approaches for the identification of proteins and polysaccharides during cell wall assembly are discussed.
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Affiliation(s)
- Marisa S Otegui
- Department of Botany, University of Wisconsin, Madison, WI, USA.
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40
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Mahmoudi A, Reihani SNS. Phase contrast optical tweezers. Opt Express 2010; 18:17983-17996. [PMID: 20721185 DOI: 10.1364/oe.18.017983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In this paper, for the first time, we report on systematic theoretical and experimental investigation of Phase Contrast Optical Tweezers (PCOT) which could be an indispensable tool for micromanipulation of the transparent micro and nano objects such as biological tissues and vesicles. The quadrant photodiode detection scheme and the power-spectrum calibration method is shown to be valid for this case. We have shown that the phase objective with new designed phase plates can provide nearly aberration-free condition at a desired depth. This could be a valuable advantage for simultaneous in-depth micro-manipulations and visualization of the sample.
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Affiliation(s)
- Ali Mahmoudi
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Gava Zang, P.O.Box: 45195-1159, Zanjan 45137-66731, Iran
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41
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Takagi H, Hiroi T, Hirose S, Yang L, Takaiwa F. Rice seed ER-derived protein body as an efficient delivery vehicle for oral tolerogenic peptides. Peptides 2010; 31:1421-5. [PMID: 20457197 DOI: 10.1016/j.peptides.2010.04.032] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 04/30/2010] [Accepted: 04/30/2010] [Indexed: 02/08/2023]
Abstract
Mucosal delivery of peptide/protein therapeutics via the oral route is a desirable strategy in human immunotherapy. A key step for enhancing the bioavailability of orally administered therapeutics is to protect them from enzymatic digestion in the gastrointestinal tract. Here, we generated transgenic rice seeds accumulating allergen-derived T cell epitopes, a model tolerogen for the control of pollen allergy, in either ER-derived protein body-I (PB-I) or protein storage vacuole protein body-II (PB-II). Compared with PB-II-localized or chemically synthesized forms, PB-I-localized T cell epitopes showed higher resistance to enzymatic digestion in simulated gastric fluid. Moreover, the dose of T cell epitope required for suppression of allergen-specific IgE in mice was about 20-fold lower when fed in PB-I localized form than when unprotected. These findings demonstrate the potential of bioencapsulation in PB-I for broad applications as a viable strategy to achieve efficient mucosal delivery of oral peptide/protein therapeutics.
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Affiliation(s)
- Hidenori Takagi
- Transgenic Crop Research and Development Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
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42
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Pusiol T, Franceschetti I, Scialpi M, Piscioli I, Tardio ML. Electron microscopy: the gold standard in the differential diagnosis of chromophobe renal cell carcinoma and oncocytoma. Anal Quant Cytol Histol 2010; 32:58-60. [PMID: 20701089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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43
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Kaoui B, Farutin A, Misbah C. Vesicles under simple shear flow: elucidating the role of relevant control parameters. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:061905. [PMID: 20365188 DOI: 10.1103/physreve.80.061905] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/13/2009] [Indexed: 05/29/2023]
Abstract
The dynamics of vesicles under shear flow are carefully analyzed in the regime of a small vesicle excess area relative to a sphere. This regime corresponds to the quasispherical limit, for which several groups have analytically extracted simple nonlinear differential equations. Under shear flow, vesicles are known to exhibit three types of motion: (i) tank-treading (TT): the vesicle assumes a steady inclination angle with respect to the flow direction, while its membrane undergoes a tank-treading motion, (ii) tumbling (TB), and (iii) vacillating-breathing (VB): the vesicle main axis oscillates about the flow direction, whereas the overall shape undergoes a breathinglike motion. The region of existence for each regime depends on material and control parameters. The whole set of parameters can be cast into three dimensionless control parameters: (i) the viscosity ratio between the internal and external fluid, lambda , (ii) the excess area relative to a sphere (this parameter measures the degree of the vesicle deflation), Delta , and (iii) the capillary number (the ratio between the vesicle relaxation time toward its equilibrium shape after cessation of the flow and the flow time scale, which is the inverse shear rate), Ca. Recent studies [Danker, Phys. Rev. E 76, 041905 (2007)] have focused on the shape of the phase diagram (representing the TT, TB, and VB regimes in the Ca-lambda plane). In this paper, the physical quantities are analyzed in detail and attention is brought to features that are essential for future experimental studies. It is shown that the boundaries delimiting different dynamical regimes (TT, TB, and VB) in parameter space depend on the three dimensionless control parameters, in contrast with a recent study [V. V. Lebedev, Phys. Rev. Lett. 99, 218101 (2007)] where it is claimed that only two parameters are relevant. Consideration of the amplitude of oscillation (of the vesicle orientation angle and its shape deformation) in the VB mode reveals an even more significant dependence on the three parameters. It is also shown that the inclination angle in the TT regime significantly depends on the shear rate (Ca), which runs contrary to common belief. Finally, we show that the TB and VB periods are quite insensitive to Ca, in marked contrast with a recent study [H. Noguchi and G. Gompper, Phys. Rev. Lett. 98, 128103 (2007)].
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Affiliation(s)
- Badr Kaoui
- Laboratoire de Spectrométrie Physique, CNRS-Université Joseph Fourier/UMR 5588, Boîte Postale 87, F-38402 Saint-Martin d'Hères Cedex, France
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Fuhrmann E, Bultema JB, Kahmann U, Rupprecht E, Boekema EJ, Schneider D. The vesicle-inducing protein 1 from Synechocystis sp. PCC 6803 organizes into diverse higher-ordered ring structures. Mol Biol Cell 2009; 20:4620-8. [PMID: 19776353 PMCID: PMC2770949 DOI: 10.1091/mbc.e09-04-0319] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 09/10/2009] [Accepted: 09/15/2009] [Indexed: 11/11/2022] Open
Abstract
The vesicle-inducing protein in plastids 1 (Vipp1) was found to be involved in thylakoid membrane formation in chloroplasts and cyanobacteria. In contrast to chloroplasts, it has been suggested that in cyanobacteria the protein is only tightly associated with the cytoplasmic membrane. In the present study we analyze and describe the subcellular localization and the oligomeric organization of Vipp1 from the cyanobacterium Synechocystis PCC 6803. Vipp1 forms stable dimers and higher-ordered oligomers in the cytoplasm as well as at both the cytoplasmic and thylakoid membrane. Vipp1 oligomers are organized in ring structures with a variable diameter of 25-33 nm and corresponding calculated molecular masses of approximately 1.6-2.2 MDa. Six different types of rings were found with an unusual 12-17-fold symmetrical conformation. The simultaneous existence of multiple types of rings is very unusual and suggests a special function of Vipp1. Involvement of diverse ring structures in vesicle formation is suggested.
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Affiliation(s)
- Eva Fuhrmann
- *Institut für Biochemie und Molekularbiologie, ZBMZ
- Fakultät für Biologie, Albert-Ludwigs-Universität, 79104 Freiburg, Germany
| | - Jelle B. Bultema
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; and
| | - Uwe Kahmann
- Fakultät für Biologie, Universität Bielefeld, D-33501 Bielefeld, Germany
| | | | - Egbert J. Boekema
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; and
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Abstract
Chromophobe renal cell carcinoma (CRCC) is a distinct variant of renal epithelial neoplasm. Ultrastructurally, the presence of numerous cytoplasmic microvesicles is highly characteristic of CRCC, as are mitochondria with tubulovesicular cristae. All 18 cases is this study present these two elements with a different distribution, depending on the morphological variant (typìcal or eosinophilic). In both variants, the mitochondria show tubulovesicular cristae and budding from the outer mitochondrial membrane that is very similar to the cytoplasmic microvesicles. An association was also found between intracristal mitochondrial swelling and bud formation. These buds, when detached from the mitochondrial membrane, may convert into the cytoplasmic microvesicles.
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Affiliation(s)
- Santiago Montes Moreno
- Departamento de Anatomía Patológica, Hospital Universitario 12 de Octubre, Madrid, Spain
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Hägerstrand H, Mrówczyńska L, Salzer U, Prohaska R, Michelsen KA, Kralj-Iglic V, Iglic A. Curvature-dependent lateral distribution of raft markers in the human erythrocyte membrane. Mol Membr Biol 2009; 23:277-88. [PMID: 16785211 DOI: 10.1080/09687860600682536] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [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: 10/24/2022]
Abstract
The distribution of raft markers in curved membrane exvaginations and invaginations, induced in human erythrocytes by amphiphile-treatment or increased cytosolic calcium level, was studied by fluorescence microscopy. Cholera toxin subunit B and antibodies were used to detect raft components. Ganglioside GM1 was enriched in membrane exvaginations (spiculae) induced by cytosolic calcium and amphiphiles. Stomatin and the cytosolic proteins synexin and sorcin were enriched in spiculae when induced by cytosolic calcium, but not in spiculae induced by amphiphiles. No enrichment of flotillin-1 was detected in spiculae. Analyses of the relative protein content of released exovesicles were in line with the microscopic observations. In invaginations induced by amphiphiles, the enrichment of ganglioside GM1, but not of the integral membrane proteins flotillin-1 and stomatin, was observed. Based on the experimental results and theoretical considerations we suggest that membrane skeleton-detached, laterally mobile rafts may sort into curved or flat membrane regions dependent on their intrinsic molecular shape and/or direct interactions between the raft elements.
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Abstract
A hydrogenosome is a hydrogen-producing organelle, evolutionary related to mitochondria and is found in Parabasalia protozoa, certain chytrid fungi and certain ciliates. It displays similarities to and differences from mitochondria. Hydrogenosomes are spherical or slightly elongated organelles, although very elongated hydrogenosomes are also found. They measure from 200 nm to 1 microm, but under stress conditions can reach up to 2 microm. Hydrogenosomes are surrounded by two closely apposed membranes and present a granular matrix. Cardiolipin has been detected in their membranes, and frataxin, which is a conserved mitochondrial protein involved in iron metabolism, was also recently found. Hydrogenosomes have one or multiple peripheral vesicles, which incorporate calcium. The peripheral vesicle can be isolated from the hydrogenosomal matrix and can be considered as a distinct hydrogenosomal compartment. Dysfunctional hydrogenosomes can be removed by an autophagic process and further digested by lysosomes. Hydrogenosomes divide in three different ways, like mitochondria, by segmentation, partition and the heart form. They may divide at any phase of the cell cycle. Nucleoid or electron dense deposits found in hydrogenosomes can be considered artifacts or dysfunctional hydrogenosomes. The hydrogenosome does not contain a genome, although DNA has already been detected in one anaerobic ciliate. Hydrogenosomes can be considered as good drug targets since their metabolism is distinct from mitochondria.
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Affiliation(s)
- Marlene Benchimol
- Universidade Santa Ursula, Laboratório de Ultraestrutura Celular, Rio de Janeiro, Brazil.
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Benninger RK, Vanherberghen B, Young S, Taner SB, Culley FJ, Schnyder T, Neil MA, Wüstner D, French PM, Davis DM, Önfelt B. Live cell linear dichroism imaging reveals extensive membrane ruffling within the docking structure of natural killer cell immune synapses. Biophys J 2009; 96:L13-5. [PMID: 19167281 PMCID: PMC2716478 DOI: 10.1016/j.bpj.2008.10.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022] Open
Abstract
We have applied fluorescence imaging of two-photon linear dichroism to measure the subresolution organization of the cell membrane during formation of the activating (cytolytic) natural killer (NK) cell immune synapse (IS). This approach revealed that the NK cell plasma membrane is convoluted into ruffles at the periphery, but not in the center of a mature cytolytic NK cell IS. Time-lapse imaging showed that the membrane ruffles formed at the initial point of contact between NK cells and target cells and then spread radialy across the intercellular contact as the size of the IS increased, becoming absent from the center of the mature synapse. Understanding the role of such extensive membrane ruffling in the assembly of cytolytic synapses is an intriguing new goal.
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Affiliation(s)
| | - Bruno Vanherberghen
- Cell Physics, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Stephen Young
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Sabrina B. Taner
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Fiona J. Culley
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Tim Schnyder
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Mark A.A. Neil
- Department of Physics, Imperial College London, London, United Kingdom
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Paul M.W. French
- Department of Physics, Imperial College London, London, United Kingdom
| | - Daniel M. Davis
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Björn Önfelt
- Cell Physics, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Li Y, Nakayama H, Notani T, Ahmad M, Tabata MJ, Takano Y. Phosphatase actions at the site of appositional mineralization in bisphosphonate-affected bones of the rat. J Med Dent Sci 2008; 55:255-265. [PMID: 19697513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Tissue-nonspecific alkaline phosphatase (TNSALP) and Ca-ATPase are known to play roles in bone mineralization, but how these enzymes contribute to appositional mineralization has been illusive. Here we examined the active sites of these enzymes in appositional mineralization using the bones of young rats being administered with 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 5 days. The doses of HEBP totally abolished mineralization of newly formed bone matrix except in matrix vesicles (MVs), and hence allowed precise localization of MVs and phosphatase reactions within non-mineralized extracellular matrix. Intense TNSALP and ATPase reactions were confirmed along the limited portions of osteoblast membranes where intimate cell-cell contacts were maintained. Diffuse reactions of these enzymes were throughout the osteoid implicating efflux of TNSALP and ATPase molecules into extracellular matrix from the osteoblast membranes. Phosphatase reactions associated with MVs varied both in intensity and location among the individual vesicles; newly formed MVs were almost free of reactions but appeared to gain those activities later in the osteoid. These data suggest that TNSALP and ATPase are released from the osteoblast membrane and later integrated into MVs within the osteoid. The osteoblasts may thus regulate appositional mineralization of bone from a distance at least in part by providing phosphatases via MVs.
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Affiliation(s)
- Yi Li
- Section of Biostructural Science, Department of Hard Tissue Engineering, Division of Bio-Matrix, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
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da Silva-Lopez RE, Morgado-Díaz JA, dos Santos PT, Giovanni-De-Simone S. Purification and subcellular localization of a secreted 75 kDa Trypanosoma cruzi serine oligopeptidase. Acta Trop 2008; 107:159-67. [PMID: 18599007 DOI: 10.1016/j.actatropica.2008.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 05/20/2008] [Accepted: 05/22/2008] [Indexed: 11/17/2022]
Abstract
An extracellular serine peptidase was purified 460-fold from Trypanosoma cruzi epimastigotes culture supernatant with (NH(4))(2)SO(4) precipitation followed by affinity chromatography aprotinin-agarose and continuous elution electrophoresis, yielding a total recovery of 65%. The molecular mass of the active enzyme estimated by reducing and non-reducing SDS-PAGE was about 75kDa. The optimal pH and temperature of this glycosylated peptidase were 8.0 and 37 degrees C using alpha-N-rho-tosyl-L-arginine-methyl ester (L-TAME) as substrate. The enzyme did not hydrolyze polypeptide substrates but was active against short peptide substrates containing arginine at the P1 site, in both ester and amide bonds. The peptidase was inhibited by TPCK and TCLK but not by other protease inhibitors suggesting that the enzyme belongs to the serine peptidase class. Interestingly, the enzyme seems to demonstrate some metal dependence since its activity was reduced by 1,10-phenanthroline, calcium and zinc ions. Rabbit anti-T. cruzi extracellular serine peptidase antiserum was used to show that the enzyme was restricted to intracellular structures, including the flagellar pocket, plasma membrane and cytoplasmic vesicles resembling reservosomes. These results suggest that the serine oligopeptidase is secreted into the extracellular environment through the flagellar pocket and the intracellular location could suggest its participation in certain proteolysis events in reservosomes. These findings show that this peptidase is a novel T. cruzi serine oligopeptidase, which differs not only from other peptidases described in the same parasite but also in other species of Trypanosoma.
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