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Antao NV, Sall J, Petzold C, Ekiert DC, Bhabha G, Liang FX. Sample preparation and data collection for serial block face scanning electron microscopy of mammalian cell monolayers. PLoS One 2024; 19:e0301284. [PMID: 39121154 PMCID: PMC11315281 DOI: 10.1371/journal.pone.0301284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 02/26/2024] [Indexed: 08/11/2024] Open
Abstract
Volume electron microscopy encompasses a set of electron microscopy techniques that can be used to examine the ultrastructure of biological tissues and cells in three dimensions. Two block face techniques, focused ion beam scanning electron microscopy (FIB-SEM) and serial block face scanning electron microscopy (SBF-SEM) have often been used to study biological tissue samples. More recently, these techniques have been adapted to in vitro tissue culture samples. Here we describe step-by-step protocols for two sample embedding methods for in vitro tissue culture cells intended to be studied using SBF-SEM. The first focuses on cell pellet embedding and the second on en face embedding. En face embedding can be combined with light microscopy, and this CLEM workflow can be used to identify specific biological events by light microscopy, which can then be imaged using SBF-SEM. We systematically outline the steps necessary to fix, stain, embed and image adherent tissue culture cell monolayers by SBF-SEM. In addition to sample preparation, we discuss optimization of parameters for data collection. We highlight the challenges and key steps of sample preparation, and the consideration of imaging variables.
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Affiliation(s)
- Noelle V. Antao
- Department of Cell Biology, New York University School of Medicine, New York, NY, United States of America
| | - Joseph Sall
- Office of Science and Research Microscopy Laboratory, New York University School of Medicine, New York, NY, United States of America
| | - Christopher Petzold
- Office of Science and Research Microscopy Laboratory, New York University School of Medicine, New York, NY, United States of America
| | - Damian C. Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, NY, United States of America
- Department of Microbiology, New York University School of Medicine, New York, NY, United States of America
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, NY, United States of America
| | - Feng-Xia Liang
- Department of Cell Biology, New York University School of Medicine, New York, NY, United States of America
- Office of Science and Research Microscopy Laboratory, New York University School of Medicine, New York, NY, United States of America
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2
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Kolluru C, Joseph N, Seckler J, Fereidouni F, Levenson R, Shoffstall A, Jenkins M, Wilson D. NerveTracker: a Python-based software toolkit for visualizing and tracking groups of nerve fibers in serial block-face microscopy with ultraviolet surface excitation images. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:076501. [PMID: 38912214 PMCID: PMC11188586 DOI: 10.1117/1.jbo.29.7.076501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 06/25/2024]
Abstract
Significance Information about the spatial organization of fibers within a nerve is crucial to our understanding of nerve anatomy and its response to neuromodulation therapies. A serial block-face microscopy method [three-dimensional microscopy with ultraviolet surface excitation (3D-MUSE)] has been developed to image nerves over extended depths ex vivo. To routinely visualize and track nerve fibers in these datasets, a dedicated and customizable software tool is required. Aim Our objective was to develop custom software that includes image processing and visualization methods to perform microscopic tractography along the length of a peripheral nerve sample. Approach We modified common computer vision algorithms (optic flow and structure tensor) to track groups of peripheral nerve fibers along the length of the nerve. Interactive streamline visualization and manual editing tools are provided. Optionally, deep learning segmentation of fascicles (fiber bundles) can be applied to constrain the tracts from inadvertently crossing into the epineurium. As an example, we performed tractography on vagus and tibial nerve datasets and assessed accuracy by comparing the resulting nerve tracts with segmentations of fascicles as they split and merge with each other in the nerve sample stack. Results We found that a normalized Dice overlap (Dice norm ) metric had a mean value above 0.75 across several millimeters along the nerve. We also found that the tractograms were robust to changes in certain image properties (e.g., downsampling in-plane and out-of-plane), which resulted in only a 2% to 9% change to the meanDice norm values. In a vagus nerve sample, tractography allowed us to readily identify that subsets of fibers from four distinct fascicles merge into a single fascicle as we move ∼ 5 mm along the nerve's length. Conclusions Overall, we demonstrated the feasibility of performing automated microscopic tractography on 3D-MUSE datasets of peripheral nerves. The software should be applicable to other imaging approaches. The code is available at https://github.com/ckolluru/NerveTracker.
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Affiliation(s)
- Chaitanya Kolluru
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
| | - Naomi Joseph
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
| | - James Seckler
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
| | - Farzad Fereidouni
- UC Davis Medical Center, Department of Pathology and Laboratory Medicine, Sacramento, California, United States
| | - Richard Levenson
- UC Davis Medical Center, Department of Pathology and Laboratory Medicine, Sacramento, California, United States
| | - Andrew Shoffstall
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States
| | - Michael Jenkins
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States
- Case Western Reserve University, Department of Pediatrics, Cleveland, Ohio, United States
| | - David Wilson
- Case Western Reserve University, Department of Biomedical Engineering, Cleveland, Ohio, United States
- Case Western Reserve University, Department of Radiology, Cleveland, Ohio, United States
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3
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Tisoncik-Go J, Stokes C, Whitmore LS, Newhouse DJ, Voss K, Gustin A, Sung CJ, Smith E, Stencel-Baerenwald J, Parker E, Snyder JM, Shaw DW, Rajagopal L, Kapur RP, Adams Waldorf KM, Gale M. Disruption of myelin structure and oligodendrocyte maturation in a macaque model of congenital Zika infection. Nat Commun 2024; 15:5173. [PMID: 38890352 PMCID: PMC11189406 DOI: 10.1038/s41467-024-49524-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 06/06/2024] [Indexed: 06/20/2024] Open
Abstract
Zika virus (ZikV) infection during pregnancy can cause congenital Zika syndrome (CZS) and neurodevelopmental delay in infants, of which the pathogenesis remains poorly understood. We utilize an established female pigtail macaque maternal-to-fetal ZikV infection/exposure model to study fetal brain pathophysiology of CZS manifesting from ZikV exposure in utero. We find prenatal ZikV exposure leads to profound disruption of fetal myelin, with extensive downregulation in gene expression for key components of oligodendrocyte maturation and myelin production. Immunohistochemical analyses reveal marked decreases in myelin basic protein intensity and myelinated fiber density in ZikV-exposed animals. At the ultrastructural level, the myelin sheath in ZikV-exposed animals shows multi-focal decompaction, occurring concomitant with dysregulation of oligodendrocyte gene expression and maturation. These findings define fetal neuropathological profiles of ZikV-linked brain injury underlying CZS resulting from ZikV exposure in utero. Because myelin is critical for cortical development, ZikV-related perturbations in oligodendrocyte function may have long-term consequences on childhood neurodevelopment, even in the absence of overt microcephaly.
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Affiliation(s)
- Jennifer Tisoncik-Go
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA.
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA.
| | - Caleb Stokes
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
| | - Leanne S Whitmore
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Daniel J Newhouse
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Kathleen Voss
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Andrew Gustin
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Cheng-Jung Sung
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Elise Smith
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Jennifer Stencel-Baerenwald
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA
| | - Edward Parker
- Department of Ophthalmology, NEI Core for Vision Research, University of Washington, Seattle, WA, USA
| | - Jessica M Snyder
- Department of Comparative Medicine, University of Washington, Seattle, WA, USA
| | - Dennis W Shaw
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Lakshmi Rajagopal
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Raj P Kapur
- Department of Pathology, University of Washington, Seattle, WA, USA
- Department of Pathology, Seattle Children's Hospital, Seattle, WA, USA
| | - Kristina M Adams Waldorf
- Department of Global Health, University of Washington, Seattle, WA, USA
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, USA
| | - Michael Gale
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, WA, USA.
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA.
- Department of Global Health, University of Washington, Seattle, WA, USA.
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4
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St-Pierre MK, González Ibáñez F, Kroner A, Tremblay MÈ. Microglia/macrophages are ultrastructurally altered by their proximity to spinal cord injury in adult female mice. J Neuroinflammation 2023; 20:273. [PMID: 37990235 PMCID: PMC10664529 DOI: 10.1186/s12974-023-02953-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/08/2023] [Indexed: 11/23/2023] Open
Abstract
Traumatic spinal cord injury can cause immediate physical damage to the spinal cord and result in severe neurological deficits. The primary, mechanical tissue damage triggers a variety of secondary damage mechanisms at the injury site which significantly contribute to a larger lesion size and increased functional damage. Inflammatory mechanisms which directly involve both microglia (MG) and monocyte-derived macrophages (MDM) play important roles in the post-injury processes, including inflammation and debris clearing. In the current study, we investigated changes in the structure and function of MG/MDM in the injured spinal cord of adult female mice, 7 days after a thoracic contusion SCI. With the use of chip mapping scanning electron microscopy, which allows to image large samples at the nanoscale, we performed an ultrastructural comparison of MG/MDM located near the lesion vs adjacent regions to provide novel insights into the mechanisms at play post-injury. We found that MG/MDM located near the lesion had more mitochondria overall, including mitochondria with and without morphological alterations, and had a higher proportion of altered mitochondria. MG/MDM near the lesion also showed an increased number of phagosomes, including phagosomes containing myelin and partiallydigested materials. MG/MDM near the injury interacted differently with the spinal cord parenchyma, as shown by their reduced number of direct contacts with synaptic elements, axon terminals and dendritic spines. In this study, we characterized the ultrastructural changes of MG/MDM in response to spinal cord tissue damage in mice, uncovering changes in phagocytic activity, mitochondrial ultrastructure, and inter-cellular interactions within the spinal cord parenchyma.
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Affiliation(s)
- Marie-Kim St-Pierre
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec City, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
| | - Fernando González Ibáñez
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec City, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
| | - Antje Kroner
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA.
- Clement J. Zablocki Veterans Affairs Medical Center, 5000 W. National Ave, Milwaukee, WI, 53295, USA.
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec City, QC, Canada.
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada.
- Division of Medical Sciences, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada.
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada.
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.
- Centre for Advanced Materials and Related Technology (CAMTEC) and Institute on Aging and Lifelong Health (IALH), University of Victoria, Victoria, BC, Canada.
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5
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Tisoncik-Go J, Stokes C, Whitmore LS, Newhouse DJ, Voss K, Gustin A, Sung CJ, Smith E, Stencel-Baerenwald J, Parker E, Snyder JM, Shaw DW, Rajagopal L, Kapur RP, Waldorf KA, Gale M. Disruption of myelin structure and oligodendrocyte maturation in a pigtail macaque model of congenital Zika infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.11.561759. [PMID: 37873381 PMCID: PMC10592731 DOI: 10.1101/2023.10.11.561759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Zika virus (ZikV) infection during pregnancy can cause congenital Zika syndrome (CZS) and neurodevelopmental delay in non-microcephalic infants, of which the pathogenesis remains poorly understood. We utilized an established pigtail macaque maternal-to-fetal ZikV infection/exposure model to study fetal brain pathophysiology of CZS manifesting from ZikV exposure in utero. We found prenatal ZikV exposure led to profound disruption of fetal myelin, with extensive downregulation in gene expression for key components of oligodendrocyte maturation and myelin production. Immunohistochemical analyses revealed marked decreases in myelin basic protein intensity and myelinated fiber density in ZikV-exposed animals. At the ultrastructural level, the myelin sheath in ZikV-exposed animals showed multi-focal decompaction consistent with perturbation or remodeling of previously formed myelin, occurring concomitant with dysregulation of oligodendrocyte gene expression and maturation. These findings define fetal neuropathological profiles of ZikV-linked brain injury underlying CZS resulting from ZikV exposure in utero. Because myelin is critical for cortical development, ZikV-related perturbations in oligodendrocyte function may have long-term consequences on childhood neurodevelopment, even in the absence of overt microcephaly.
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Affiliation(s)
- Jennifer Tisoncik-Go
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Caleb Stokes
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Leanne S Whitmore
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Daniel J Newhouse
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Kathleen Voss
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Andrew Gustin
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Cheng-Jung Sung
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Elise Smith
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Jennifer Stencel-Baerenwald
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Edward Parker
- Department of Ophthalmology, NEI Core for Vision Research, University of Washington, Seattle, Washington, USA
| | - Jessica M Snyder
- Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Dennis W Shaw
- Department of Radiology, University of Washington, Seattle Washington, USA
| | - Lakshmi Rajagopal
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Raj P Kapur
- Department of Pathology, University of Washington, Seattle, Washington, USA
- Department of Pathology, Seattle Children's Hospital, Seattle, Washington, USA
| | - Kristina Adams Waldorf
- Department of Global Health, University of Washington, Seattle, Washington, USA
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, USA
- Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Michael Gale
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, USA
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6
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Marshall AG, Neikirk K, Stephens DC, Vang L, Vue Z, Beasley HK, Crabtree A, Scudese E, Lopez EG, Shao B, Krystofiak E, Rutledge S, Davis J, Murray SA, Damo SM, Katti P, Hinton A. Serial Block Face-Scanning Electron Microscopy as a Burgeoning Technology. Adv Biol (Weinh) 2023; 7:e2300139. [PMID: 37246236 PMCID: PMC10950369 DOI: 10.1002/adbi.202300139] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 05/09/2023] [Indexed: 05/30/2023]
Abstract
Serial block face scanning electron microscopy (SBF-SEM), also referred to as serial block-face electron microscopy, is an advanced ultrastructural imaging technique that enables three-dimensional visualization that provides largerx- and y-axis ranges than other volumetric EM techniques. While SEM is first introduced in the 1930s, SBF-SEM is developed as a novel method to resolve the 3D architecture of neuronal networks across large volumes with nanometer resolution by Denk and Horstmann in 2004. Here, the authors provide an accessible overview of the advantages and challenges associated with SBF-SEM. Beyond this, the applications of SBF-SEM in biochemical domains as well as potential future clinical applications are briefly reviewed. Finally, the alternative forms of artificial intelligence-based segmentation which may contribute to devising a feasible workflow involving SBF-SEM, are also considered.
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Affiliation(s)
- Andrea G Marshall
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Kit Neikirk
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Dominique C Stephens
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Larry Vang
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Zer Vue
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Heather K Beasley
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Amber Crabtree
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Estevão Scudese
- Laboratory of Biosciences of Human Motricity (LABIMH) of the Federal University of State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Sport Sciences and Exercise Laboratory (LaCEE), Catholic University of Petrópolis (UCP), Catholic, 25685-100, Brazil
| | - Edgar Garza Lopez
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Bryanna Shao
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Evan Krystofiak
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Sharifa Rutledge
- Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL, 35899, USA
| | - Jaimaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience, Pharmacology, Meharry Medical College, Nashville, TN, 37232, USA
| | - Sandra A Murray
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Nashville, TN, 37208, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Prasanna Katti
- National Heart, Lung and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
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7
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel-Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave KA, Werner HB. Focused ion beam-scanning electron microscopy links pathological myelin outfoldings to axonal changes in mice lacking Plp1 or Mag. Glia 2023; 71:509-523. [PMID: 36354016 DOI: 10.1002/glia.24290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Healthy myelin sheaths consist of multiple compacted membrane layers closely encasing the underlying axon. The ultrastructure of CNS myelin requires specialized structural myelin proteins, including the transmembrane-tetraspan proteolipid protein (PLP) and the Ig-CAM myelin-associated glycoprotein (MAG). To better understand their functional relevance, we asked to what extent the axon/myelin-units display similar morphological changes if PLP or MAG are lacking. We thus used focused ion beam-scanning electron microscopy (FIB-SEM) to re-investigate axon/myelin-units side-by-side in Plp- and Mag-null mutant mice. By three-dimensional reconstruction and morphometric analyses, pathological myelin outfoldings extend up to 10 μm longitudinally along myelinated axons in both models. More than half of all assessed outfoldings emerge from internodal myelin. Unexpectedly, three-dimensional reconstructions demonstrated that both models displayed complex axonal pathology underneath the myelin outfoldings, including axonal sprouting. Axonal anastomosing was additionally observed in Plp-null mutant mice. Importantly, normal-appearing axon/myelin-units displayed significantly increased axonal diameters in both models according to quantitative assessment of electron micrographs. These results imply that healthy CNS myelin sheaths facilitate normal axonal diameters and shape, a function that is impaired when structural myelin proteins PLP or MAG are lacking.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Leonie C Schadt
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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8
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Lins BR, Anyaegbu CC, McGonigle T, Hellewell SC, Patel P, Reagan H, Rooke-Wiesner C, Warnock A, Archer M, Hemmi JM, Bartlett C, Fitzgerald M. Secondary Degeneration Impairs Myelin Ultrastructural Development in Adulthood following Adolescent Neurotrauma in the Rat Optic Nerve. Int J Mol Sci 2023; 24:ijms24043343. [PMID: 36834755 PMCID: PMC9966883 DOI: 10.3390/ijms24043343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
Adolescence is a critical period of postnatal development characterized by social, emotional, and cognitive changes. These changes are increasingly understood to depend on white matter development. White matter is highly vulnerable to the effects of injury, including secondary degeneration in regions adjacent to the primary injury site which alters the myelin ultrastructure. However, the impact of such alterations on adolescent white matter maturation is yet to be investigated. To address this, female piebald-virol-glaxo rats underwent partial transection of the optic nerve during early adolescence (postnatal day (PND) 56) with tissue collection two weeks (PND 70) or three months later (PND 140). Axons and myelin in the transmission electron micrographs of tissue adjacent to the injury were classified and measured based on the appearance of the myelin laminae. Injury in adolescence impaired the myelin structure in adulthood, resulting in a lower percentage of axons with compact myelin and a higher percentage of axons with severe myelin decompaction. Myelin thickness did not increase as expected into adulthood after injury and the relationship between the axon diameter and myelin thickness in adulthood was altered. Notably, dysmyelination was not observed 2 weeks postinjury. In conclusion, injury in adolescence altered the developmental trajectory, resulting in impaired myelin maturation when assessed at the ultrastructural level in adulthood.
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Affiliation(s)
- Brittney R. Lins
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Chidozie C. Anyaegbu
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
- Correspondence:
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Sarah C. Hellewell
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Parth Patel
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Harry Reagan
- School of Biological Sciences, The University of Western Australia, Perth, WA 6009, Australia
| | - Cara Rooke-Wiesner
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Andrew Warnock
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Michael Archer
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Jan M. Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, WA 6009, Australia
- Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia
| | - Carole Bartlett
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
| | - Melinda Fitzgerald
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6845, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA 6009, Australia
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9
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Lambiri DW, Levin LA. Modeling Reactive Oxygen Species-Induced Axonal Loss in Leber Hereditary Optic Neuropathy. Biomolecules 2022; 12:1411. [PMID: 36291620 PMCID: PMC9599876 DOI: 10.3390/biom12101411] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Leber hereditary optic neuropathy (LHON) is a rare syndrome that results in vision loss. A necessary but not sufficient condition for its onset is the existence of known mitochondrial DNA mutations that affect complex I biomolecular structure. Cybrids with LHON mutations generate higher rates of reactive oxygen species (ROS). This study models how ROS, particularly H2O2, could signal and execute the axonal degeneration process that underlies LHON. We modeled and explored several hypotheses regarding the influence of H2O2 on the dynamics of propagation of axonal degeneration in LHON. Zonal oxidative stress, corresponding to H2O2 gradients, correlated with the morphology of injury exhibited in the LHON pathology. If the axonal membrane is highly permeable to H2O2 and oxidative stress induces larger production of H2O2, small injuries could trigger cascading failures of neighboring axons. The cellular interdependence created by H2O2 diffusion, and the gradients created by tissue variations in H2O2 production and scavenging, result in injury patterns and surviving axonal loss distributions similar to LHON tissue samples. Specifically, axonal degeneration starts in the temporal optic nerve, where larger groups of small diameter fibers are located and propagates from that region. These findings correlate well with clinical observations of central loss of visual field, visual acuity, and color vision in LHON, and may serve as an in silico platform for modeling the mechanism of action for new therapeutics.
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Affiliation(s)
- Darius W. Lambiri
- Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Leonard A. Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, QC H4A 3S5, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
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10
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The Mechanical Microenvironment Regulates Axon Diameters Visualized by Cryo-Electron Tomography. Cells 2022; 11:cells11162533. [PMID: 36010609 PMCID: PMC9406316 DOI: 10.3390/cells11162533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/07/2022] [Accepted: 08/10/2022] [Indexed: 12/21/2022] Open
Abstract
Axonal varicosities or swellings are enlarged structures along axon shafts and profoundly affect action potential propagation and synaptic transmission. These structures, which are defined by morphology, are highly heterogeneous and often investigated concerning their roles in neuropathology, but why they are present in the normal brain remains unknown. Combining confocal microscopy and cryo-electron tomography (Cryo-ET) with in vivo and in vitro systems, we report that non-uniform mechanical interactions with the microenvironment can lead to 10-fold diameter differences within an axon of the central nervous system (CNS). In the brains of adult Thy1-YFP transgenic mice, individual axons in the cortex displayed significantly higher diameter variation than those in the corpus callosum. When being cultured on lacey carbon film-coated electron microscopy (EM) grids, CNS axons formed varicosities exclusively in holes and without microtubule (MT) breakage, and they contained mitochondria, multivesicular bodies (MVBs), and/or vesicles, similar to the axonal varicosities induced by mild fluid puffing. Moreover, enlarged axon branch points often contain MT free ends leading to the minor branch. When the axons were fasciculated by mimicking in vivo axonal bundles, their varicosity levels reduced. Taken together, our results have revealed the extrinsic regulation of the three-dimensional ultrastructures of central axons by the mechanical microenvironment under physiological conditions.
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11
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Quality criteria for in vitro human pluripotent stem cell-derived models of tissue-based cells. Reprod Toxicol 2022; 112:36-50. [PMID: 35697279 DOI: 10.1016/j.reprotox.2022.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/27/2022] [Accepted: 06/07/2022] [Indexed: 12/21/2022]
Abstract
The advent of the technology to isolate or generate human pluripotent stem cells provided the potential to develop a wide range of human models that could enhance understanding of mechanisms underlying human development and disease. These systems are now beginning to mature and provide the basis for the development of in vitro assays suitable to understand the biological processes involved in the multi-organ systems of the human body, and will improve strategies for diagnosis, prevention, therapies and precision medicine. Induced pluripotent stem cell lines are prone to phenotypic and genotypic changes and donor/clone dependent variability, which means that it is important to identify the most appropriate characterization markers and quality control measures when sourcing new cell lines and assessing differentiated cell and tissue culture preparations for experimental work. This paper considers those core quality control measures for human pluripotent stem cell lines and evaluates the state of play in the development of key functional markers for their differentiated cell derivatives to promote assurance of reproducibility of scientific data derived from pluripotent stem cell-based systems.
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12
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Mou Q, Yao K, Ye M, Zhao B, Hu Y, Lou X, Li H, Zhang H, Zhao Y. Modulation of Sirt1-mTORC1 Pathway in Microglia Attenuates Retinal Ganglion Cell Loss After Optic Nerve Injury. J Inflamm Res 2021; 14:6857-6869. [PMID: 34934336 PMCID: PMC8684404 DOI: 10.2147/jir.s338815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/01/2021] [Indexed: 12/31/2022] Open
Abstract
Purpose Optic nerve injury (ONI) causes neuroinflammation and neurodegeneration leading to visual deficits. The response of microglia has emerged as an impactful component of etiology in neurodegeneration. This study aimed to investigate the effect of SIRT1-mTORC1 signaling pathway in microglia regulation after ONI. Methods Cx3Cr1-CreERT2/RaptorF/F and Cx3Cr1-CreERT2/Sirt1F/F mice were used to delete Raptor and Sirt1 in microglia, respectively. Optic nerve crush (ONC) model was established to mimic ONI. PLX5622, a highly specific inhibitor of the colony-stimulating factor 1 receptor (CSF1R), is used to eliminate microglia in optic nerve. Ionized calcium binding adaptor molecule 1 (Iba1) immunostaining was used to detect microglial activation. Retinal ganglion cells (RGCs) were quantified by Nissl staining and retinal whole-mount immunostaining with RNA-binding protein with multiple splicing (RBPMS). Axonal damage was valued by transmission electron microscopy (TEM). Results Microglial activation emerged on day 3 post ONC and was earlier than RGCs loss which occurred at day 5 after injury. Depleting microglia with PLX5622 could attenuate the loss of RGCs and axon damage after ONC. Gain- and loss-of-function studies revealed that SIRT1 determined the activation of microglia in optic nerve. In addition, microglia-specific deletion of Raptor resulted in decreased microglial activation. Interestingly, activating mTORC1 with CCT007093 could reverse the function of SIRT1 in regulating the process of microglial activation mediated RGCs loss. Conclusion Our study reveals a potential novel mechanism of SIRT1-mTORC1 pathway in microglia regulation, and indicates a therapeutic potential for the protection of RGCs in ONI.
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Affiliation(s)
- Qianxue Mou
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Ke Yao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Meng Ye
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Bowen Zhao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Yuanyuan Hu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Xiaotong Lou
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Huixia Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Yin Zhao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
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13
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Latini F, Fahlström M, Beháňová A, Sintorn IM, Hodik M, Staxäng K, Ryttlefors M. The link between gliomas infiltration and white matter architecture investigated with electron microscopy and diffusion tensor imaging. Neuroimage Clin 2021; 31:102735. [PMID: 34247117 PMCID: PMC8274339 DOI: 10.1016/j.nicl.2021.102735] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/23/2021] [Accepted: 06/15/2021] [Indexed: 11/21/2022]
Abstract
Diffuse low-grade gliomas (DLGG) display different preferential locations in eloquent and secondary associative brain areas. The reason for this tendency is still unknown. We hypothesized that the intrinsic architecture and water diffusion properties of the white matter bundles in these regions may facilitate gliomas infiltration. Magnetic resonance imaging of sixty-seven diffuse low-grade gliomas patients were normalized to/and segmented in MNI space to create three probabilistic infiltration weighted gradient maps according to the molecular status of each tumor group (IDH mutated, IDH wild-type and IDH mutated/1p19q co-deleted). Diffusion tensor imaging (DTI)- based parameters were derived for five major white matter bundles, displaying regional differences in the grade of infiltration, averaged over 20 healthy individuals acquired from the Human connectome project (HCP) database. Transmission electron microscopy (TEM) was used to analyze fiber density, fiber diameter and g-ratio in 100 human white matter regions, sampled from cadaver specimens, reflecting areas with different gliomas infiltration in each white matter bundle. Histological results and DTI-based parameters were compared in anatomical regions of high- and low grade of infiltration (HIF and LIF) respectively. We detected differences in the white matter infiltration of five major white matter bundles in three groups. Astrocytomas IDHm infiltrated left fronto-temporal subcortical areas. Astrocytomas IDHwt were detected in the posterior-temporal and temporo-parietal regions bilaterally. Oligodendrogliomas IDHm/1p19q infiltrated anterior subcortical regions of the frontal lobes bilaterally. Regional differences within the same white matter bundles were detected by both TEM- and DTI analysis linked to different topographical variables. Our multimodal analysis showed that HIF regions, common to all the groups, displayed a smaller fiber diameter, lower FA and higher RD compared with LIF regions. Our results suggest that the both morphological features and diffusion parameters of the white matter may be different in regions linked to the preferential location of DLGG.
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Affiliation(s)
- Francesco Latini
- Department of Neuroscience, Neurosurgery, Uppsala University, Uppsala, Sweden.
| | - Markus Fahlström
- Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden
| | - Andrea Beháňová
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Ida-Maria Sintorn
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Monika Hodik
- Immunology, Genetics and Pathology - Biovis Platform, Uppsala University, Uppsala, Sweden
| | - Karin Staxäng
- Immunology, Genetics and Pathology - Biovis Platform, Uppsala University, Uppsala, Sweden
| | - Mats Ryttlefors
- Department of Neuroscience, Neurosurgery, Uppsala University, Uppsala, Sweden
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14
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Tanaka T, Ohno N, Osanai Y, Saitoh S, Thai TQ, Nishimura K, Shinjo T, Takemura S, Tatsumi K, Wanaka A. Large-scale electron microscopic volume imaging of interfascicular oligodendrocytes in the mouse corpus callosum. Glia 2021; 69:2488-2502. [PMID: 34165804 DOI: 10.1002/glia.24055] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/16/2022]
Abstract
Single oligodendrocytes produce myelin sheaths around multiple axons in the central nervous system. Interfascicular oligodendrocytes (IOs) facilitate nerve conduction, but their detailed morphologies remain largely unknown. In the present study, we three-dimensionally reconstructed IOs in the corpus callosum of adult mouse using serial block face scanning electron microscopy. The cell bodies of IOs were morphologically polarized and extended thick processes from the cytoplasm-rich part of the cell. Processes originating from the cell body of each IO can be classified into two types: one myelinates an axon without branching, while the other type branches and each branch myelinates a distinct axon. Myelin sheaths originating from a particular IO have biased thicknesses, wrapping axons of a limited range of diameters. Consistent with this finding, IOs transduced and visualized with a rabies viral vector expressing GFP showed statistically significant variation in their myelination patterns. We further reconstructed the sheath immediately adjacent to that derived from each of the analyzed IOs; the thicknesses of the pair of sheaths were significantly correlated despite emanating from different IOs. These results suggest that a single axon could regulate myelin sheath thicknesses, even if the sheaths are derived from distinct IOs. Collectively, our results indicate that the IOs have their own myelin profiles defined by myelin thickness and axonal diameter although axons may regulate thickness of myelin sheath.
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Affiliation(s)
- Tatsuhide Tanaka
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan
| | - Yasuyuki Osanai
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.,Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Sei Saitoh
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy II and Cell Biology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Truc Quynh Thai
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan
| | - Kazuya Nishimura
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Takeaki Shinjo
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Shoko Takemura
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Kouko Tatsumi
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Akio Wanaka
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
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15
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Hernandez-Reynoso AG, Corona-Quintanilla DL, López-García K, Horbovetz AA, Castelán F, Zimmern P, Martínez-Gómez M, Romero-Ortega MI. Targeted neuromodulation of pelvic floor nerves in aging and multiparous rabbits improves continence. Sci Rep 2021; 11:10615. [PMID: 34011938 PMCID: PMC8136474 DOI: 10.1038/s41598-021-90088-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/30/2021] [Indexed: 02/03/2023] Open
Abstract
Pelvic floor muscle stretch injury during pregnancy and birth is associated with the incidence of stress urinary incontinence (SUI), a condition that affects 30-60% of the female population and is characterized by involuntary urine leakage during physical activity, further exacerbated by aging. Aging and multiparous rabbits suffer pelvic nerve and muscle damage, resulting in alterations in pelvic floor muscular contraction and low urethral pressure, resembling SUI. However, the extent of nerve injury is not fully understood. Here, we used electron microscopy analysis of pelvic and perineal nerves in multiparous rabbits to describe the extent of stretch nerve injury based on axon count, axon size, myelin-to-axon ratio, and elliptical ratio. Compared to young nulliparous controls, mid-age multiparous animals showed an increase in the density of unmyelinated axons and in myelin thickness in both nerves, albeit more significant in the bulbospongiosus nerve. This revealed a partial but sustained damage to these nerves, and the presence of some regenerated axons. Additionally, we tested whether electrical stimulation of the bulbospongiosus nerve would induce muscle contraction and urethral closure. Using a miniature wireless stimulator implanted on this perineal nerve in young nulliparous and middle age multiparous female rabbits, we confirmed that these partially damaged nerves can be acutely depolarized, either at low (2-5 Hz) or medium (10-20 Hz) frequencies, to induce a proportional increase in urethral pressure. Evaluation of micturition volume in the mid-age multiparous animals after perineal nerve stimulation, effectively reversed a baseline deficit, increasing it 2-fold (p = 0.02). These results support the notion that selective neuromodulation of pelvic floor muscles might serve as a potential treatment for SUI.
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Affiliation(s)
- Ana G Hernandez-Reynoso
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, 75390, USA
- Department of Biomedical Engineering and Biomedical Sciences, University of Houston, Houston, TX, 77204, USA
| | - Dora L Corona-Quintanilla
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, Tlaxcala, Mexico
| | - Kenia López-García
- Departamento de Biología Celular y Fisiología, Unidad Foránea Tlaxcala, Instituto de Investigaciones Biomédicas, Universidad Autónoma de México, Tlaxcala, Tlaxcala, Mexico
| | - Ana A Horbovetz
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Francisco Castelán
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, Tlaxcala, Mexico
- Departamento de Biología Celular y Fisiología, Unidad Foránea Tlaxcala, Instituto de Investigaciones Biomédicas, Universidad Autónoma de México, Tlaxcala, Tlaxcala, Mexico
| | - Philippe Zimmern
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, 75390, USA
| | - Margarita Martínez-Gómez
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, Tlaxcala, Mexico
- Departamento de Biología Celular y Fisiología, Unidad Foránea Tlaxcala, Instituto de Investigaciones Biomédicas, Universidad Autónoma de México, Tlaxcala, Tlaxcala, Mexico
| | - Mario I Romero-Ortega
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, 75390, USA.
- Department of Biomedical Engineering and Biomedical Sciences, University of Houston, Houston, TX, 77204, USA.
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, 75390, USA.
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16
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Galichet C, Clayton RW, Lovell-Badge R. Novel Tools and Investigative Approaches for the Study of Oligodendrocyte Precursor Cells (NG2-Glia) in CNS Development and Disease. Front Cell Neurosci 2021; 15:673132. [PMID: 33994951 PMCID: PMC8116629 DOI: 10.3389/fncel.2021.673132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022] Open
Abstract
Oligodendrocyte progenitor cells (OPCs), also referred to as NG2-glia, are the most proliferative cell type in the adult central nervous system. While the primary role of OPCs is to serve as progenitors for oligodendrocytes, in recent years, it has become increasingly clear that OPCs fulfil a number of other functions. Indeed, independent of their role as stem cells, it is evident that OPCs can regulate the metabolic environment, directly interact with and modulate neuronal function, maintain the blood brain barrier (BBB) and regulate inflammation. In this review article, we discuss the state-of-the-art tools and investigative approaches being used to characterize the biology and function of OPCs. From functional genetic investigation to single cell sequencing and from lineage tracing to functional imaging, we discuss the important discoveries uncovered by these techniques, such as functional and spatial OPC heterogeneity, novel OPC marker genes, the interaction of OPCs with other cells types, and how OPCs integrate and respond to signals from neighboring cells. Finally, we review the use of in vitro assay to assess OPC functions. These methodologies promise to lead to ever greater understanding of this enigmatic cell type, which in turn will shed light on the pathogenesis and potential treatment strategies for a number of diseases, such as multiple sclerosis (MS) and gliomas.
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Affiliation(s)
- Christophe Galichet
- Laboratory of Stem Cell Biology and Developmental Genetics, The Francis Crick Institute, London, United Kingdom
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17
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Costantini I, Baria E, Sorelli M, Matuschke F, Giardini F, Menzel M, Mazzamuto G, Silvestri L, Cicchi R, Amunts K, Axer M, Pavone FS. Autofluorescence enhancement for label-free imaging of myelinated fibers in mammalian brains. Sci Rep 2021; 11:8038. [PMID: 33850168 PMCID: PMC8044204 DOI: 10.1038/s41598-021-86092-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 03/09/2021] [Indexed: 12/12/2022] Open
Abstract
Analyzing the structure of neuronal fibers with single axon resolution in large volumes is a challenge in connectomics. Different technologies try to address this goal; however, they are limited either by the ineffective labeling of the fibers or in the achievable resolution. The possibility of discriminating between different adjacent myelinated axons gives the opportunity of providing more information about the fiber composition and architecture within a specific area. Here, we propose MAGIC (Myelin Autofluorescence imaging by Glycerol Induced Contrast enhancement), a tissue preparation method to perform label-free fluorescence imaging of myelinated fibers that is user friendly and easy to handle. We exploit the high axial and radial resolution of two-photon fluorescence microscopy (TPFM) optical sectioning to decipher the mixture of various fiber orientations within the sample of interest. We demonstrate its broad applicability by performing mesoscopic reconstruction at a sub-micron resolution of mouse, rat, monkey, and human brain samples and by quantifying the different fiber organization in control and Reeler mouse's hippocampal sections. Our study provides a novel method for 3D label-free imaging of nerve fibers in fixed samples at high resolution, below micrometer level, that overcomes the limitation related to the myelinated axons exogenous labeling, improving the possibility of analyzing brain connectivity.
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Affiliation(s)
- Irene Costantini
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy.
- Department of Biology, University of Florence, Florence, Italy.
- National Institute of Optics, National Research Council, Rome, Italy.
| | - Enrico Baria
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- Department of Physics, University of Florence, Florence, Italy
| | - Michele Sorelli
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- Department of Physics, University of Florence, Florence, Italy
| | - Felix Matuschke
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Francesco Giardini
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
| | - Miriam Menzel
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Giacomo Mazzamuto
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Ludovico Silvestri
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- Department of Physics, University of Florence, Florence, Italy
| | - Riccardo Cicchi
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- C. and O. Vogt Institute for Brain Research, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Markus Axer
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - Francesco Saverio Pavone
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
- Department of Physics, University of Florence, Florence, Italy
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18
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Marzan DE, Brügger-Verdon V, West BL, Liddelow S, Samanta J, Salzer JL. Activated microglia drive demyelination via CSF1R signaling. Glia 2021; 69:1583-1604. [PMID: 33620118 DOI: 10.1002/glia.23980] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 02/06/2023]
Abstract
Microgliosis is a prominent pathological feature in many neurological diseases including multiple sclerosis (MS), a progressive auto-immune demyelinating disorder. The precise role of microglia, parenchymal central nervous system (CNS) macrophages, during demyelination, and the relative contributions of peripheral macrophages are incompletely understood. Classical markers used to identify microglia do not reliably discriminate between microglia and peripheral macrophages, confounding analyses. Here, we use a genetic fate mapping strategy to identify microglia as predominant responders and key effectors of demyelination in the cuprizone (CUP) model. Colony-stimulating factor 1 (CSF1), also known as macrophage colony-stimulating factor (M-CSF) - a secreted cytokine that regulates microglia development and survival-is upregulated in demyelinated white matter lesions. Depletion of microglia with the CSF1R inhibitor PLX3397 greatly abrogates the demyelination, loss of oligodendrocytes, and reactive astrocytosis that results from CUP treatment. Electron microscopy (EM) and serial block face imaging show myelin sheaths remain intact in CUP treated mice depleted of microglia. However, these CUP-damaged myelin sheaths are lost and robustly phagocytosed upon-repopulation of microglia. Direct injection of CSF1 into CNS white matter induces focal microgliosis and demyelination indicating active CSF1 signaling can promote demyelination. Finally, mice defective in adopting a toxic astrocyte phenotype that is driven by microglia nevertheless demyelinate normally upon CUP treatment implicating microglia rather than astrocytes as the primary drivers of CUP-mediated demyelination. Together, these studies indicate activated microglia are required for and can drive demyelination directly and implicate CSF1 signaling in these events.
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Affiliation(s)
- Dave E Marzan
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA.,Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Valérie Brügger-Verdon
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
| | | | - Shane Liddelow
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
| | - Jayshree Samanta
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - James L Salzer
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
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19
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Bartmeyer PM, Biscola NP, Havton LA. A shape-adjusted ellipse approach corrects for varied axonal dispersion angles and myelination in primate nerve roots. Sci Rep 2021; 11:3150. [PMID: 33542368 PMCID: PMC7862494 DOI: 10.1038/s41598-021-82575-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/21/2021] [Indexed: 11/12/2022] Open
Abstract
Segmentation of axons in light and electron micrographs allows for quantitative high-resolution analysis of nervous tissues, but varied axonal dispersion angles result in over-estimates of fiber sizes. To overcome this technical challenge, we developed a novel shape-adjusted ellipse (SAE) determination of axonal size and myelination as an all-inclusive and non-biased tool to correct for oblique nerve fiber presentations. Our new resource was validated by light and electron microscopy against traditional methods of determining nerve fiber size and myelination in rhesus macaques as a model system. We performed detailed segmental mapping and characterized the morphological signatures of autonomic and motor fibers in primate lumbosacral ventral roots (VRs). An en bloc inter-subject variability for the preganglionic parasympathetic fibers within the L7-S2 VRs was determined. The SAE approach allows for morphological ground truth data collection and assignment of individual axons to functional phenotypes with direct implications for fiber mapping and neuromodulation studies.
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Affiliation(s)
- Petra M Bartmeyer
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,School of Electrical and Computer Engineering at University of Campinas, Campinas, SP, Brazil
| | - Natalia P Biscola
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Leif A Havton
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA. .,Departments of Neurology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. .,Departments of Neurology and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Neurology Service and RR&D National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Administration Medical Center, Bronx, NY, USA.
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20
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Wolfe T, Hoffman K, Hogan MK, Salazar B, Tang X, Chaboub L, Quini CC, Lu ZL, Horner PJ. Quantification of Myelinated Nerve Fraction and Degeneration in Spinal Cord Neuropil by SHIFT MRI. J Magn Reson Imaging 2020; 53:1162-1174. [PMID: 33098256 DOI: 10.1002/jmri.27397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Neurodegeneration is a complex cellular process linked to prompt changes in myelin integrity and gradual neuron loss. Current imaging techniques offer estimations of myelin volumes in lesions/remyelinated areas but are limited to detect subtle injury. PURPOSE To investigate whether measurements detected by a signal hierarchically isolated as a function of time-to-echo (SHIFT) MRI technique can determine changes in myelin integrity and fiber axolemma. STUDY TYPE Prospective animal model. ANIMAL MODEL Surgically demyelinated spinal cord (SC) injury model in rodents (n = 6). FIELD STRENGTH/SEQUENCE Gradient-echo spin-echo at 3T. ASSESSMENT Multicompartment T2 relaxations were computed by SHIFT MRI in 75-microns-resolution images of the SC injury penumbra region 2 weeks post-trauma. G-ratio and axolemma delamination were assessed by transmission electron microscopy (TEM) in intact and injured samples. SC myelinated nerve fraction was computed by SHIFT MRI prospectively and assessed histologically. STATISTICAL TESTS Relations between SHIFT-isolated T2 -components and TEM measurements were studied using linear regression and t-tests. Pearson's correlation and significance were computed to determine the SHIFT's sensitivity to detect myelinated fibers ratio in gray matter. Regularized least-squares-based ranking analysis was employed to determine SHIFT MRI's ability to discern intact and injured myelinated nerves. RESULTS Biexponential signals isolated by SHIFT MRI for intact vs. lesion penumbra exhibited changes in T2 , shifting from intermediate components (25 ± 2 msec) to long (43 ± 11 msec) in white matter, and similarly in gray matter regions-of-interest (31 ± 2 to 46 ± 16 msec). These changes correlated highly with TEM g-ratio and axon delamination measurements (P < 0.05). Changes in short T2 components were observed but not statistically significant (8.5 ± 0.5 to 7 ± 3 msec, P = 0.445, and 4.0 ± 0.9 to 7 ± 3 msec, P = 0.075, respectively). SHIFT MRI's ability to detect myelinated fibers within gray matter was confirmed (P < 0.001). DATA CONCLUSION Changes detected by SHIFT MRI are associated with abnormal intermembrane spaces formed upon mild injury, directly correlated with early neuro integrity loss. Level of Evidence 1 Technical Efficacy Stage 2.
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Affiliation(s)
- Tatiana Wolfe
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Kristopher Hoffman
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Matthew K Hogan
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Betsy Salazar
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Xiufeng Tang
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Lesley Chaboub
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
| | - Caio C Quini
- Department of Biological Physics, Universidade Estadual Paulista UNESP, Botucatu, Sao Paulo, Brazil
| | - Zhong-Lin Lu
- Division of Arts and Sciences, NYU Shanghai, Shanghai, China, NYU-ECNU Institute of Cognitive Neuroscience at NYU Shanghai, Shanghai, China, Center for Neural Science and Department of Psychology, New York University, New York, USA
| | - Philip J Horner
- Center for Neuroregneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
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21
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O'Hare Doig RL, Santhakumar S, Fehily B, Raja S, Solomon T, Bartlett CA, Fitzgerald M, Hodgetts SI. Acute Cellular and Functional Changes With a Combinatorial Treatment of Ion Channel Inhibitors Following Spinal Cord Injury. Front Mol Neurosci 2020; 13:85. [PMID: 32670018 PMCID: PMC7331598 DOI: 10.3389/fnmol.2020.00085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 04/24/2020] [Indexed: 01/12/2023] Open
Abstract
Reducing the extent of secondary degeneration following spinal cord injury (SCI) is necessary to preserve function, but treatment options have thus far been limited. A combination of the ion channel inhibitors Lomerizine (Lom), YM872 and oxATP, to inhibit voltage-gated Ca2+ channels, Ca2+ permeable AMPA receptors, and purinergic P2X7 receptors respectively, effectively limits secondary consequences of injury in in vitro and in vivo models of CNS injury. Here, we investigated the efficacy of these inhibitors in a clinically relevant model of SCI. Fischer (F344) rats were subjected to a moderate (150 kD) contusive SCI at thoracic level T10 and assessed at 2 weeks or 10 weeks post-injury. Lom was delivered orally twice daily and YM872 and oxATP were delivered via osmotic mini-pump implanted at the time of SCI until 2 weeks following injury. Open field locomotion analysis revealed that treatment with the three inhibitors in combination improved the rate of functional recovery of the hind limb (compared to controls) as early as 1-day post-injury, with beneficial effects persisting to 14 days post-injury, while all three inhibitors were present. At 2 weeks following combinatorial treatment, the functional improvement was associated with significantly decreased cyst size, increased immunoreactivity of β-III tubulin+ve axons, myelin basic protein, and reduced lipid peroxidation by-products, and increased CC1+ve oligodendrocytes and NG2+ve/PDGFα+ve oligodendrocyte progenitor cell densities, compared to vehicle-treated SCI animals. The combination of Lom, oxATP, and YM872 shows preclinical promise for control of secondary degeneration following SCI, and further investigation of long-term sustained treatment is warranted.
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Affiliation(s)
- Ryan L O'Hare Doig
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia.,Experimental and Regenerative Neurosciences, School of Human Sciences, The University of Western Australia, Crawley, WA, Australia.,Neil Sachse Centre for Spinal Cord Research, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.,Adelaide Spinal Research Group, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Sreya Santhakumar
- Experimental and Regenerative Neurosciences, School of Human Sciences, The University of Western Australia, Crawley, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Brooke Fehily
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Sushmitha Raja
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Tanya Solomon
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Curtin Health Innovation Research Institute, Curtin University, Nedlands, WA, Australia
| | - Stuart I Hodgetts
- Experimental and Regenerative Neurosciences, School of Human Sciences, The University of Western Australia, Crawley, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
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22
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Wang T, Li W, Martin S, Papadopulos A, Joensuu M, Liu C, Jiang A, Shamsollahi G, Amor R, Lanoue V, Padmanabhan P, Meunier FA. Radial contractility of actomyosin rings facilitates axonal trafficking and structural stability. J Cell Biol 2020; 219:e201902001. [PMID: 32182623 PMCID: PMC7199852 DOI: 10.1083/jcb.201902001] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 09/17/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023] Open
Abstract
Most mammalian neurons have a narrow axon, which constrains the passage of large cargoes such as autophagosomes that can be larger than the axon diameter. Radial axonal expansion must therefore occur to ensure efficient axonal trafficking. In this study, we reveal that the speed of various large cargoes undergoing axonal transport is significantly slower than that of small ones and that the transit of diverse-sized cargoes causes an acute, albeit transient, axonal radial expansion, which is immediately restored by constitutive axonal contractility. Using live super-resolution microscopy, we demonstrate that actomyosin-II controls axonal radial contractility and local expansion, and that NM-II filaments associate with periodic F-actin rings via their head domains. Pharmacological inhibition of NM-II activity significantly increases axon diameter by detaching the NM-II from F-actin and impacts the trafficking speed, directionality, and overall efficiency of long-range retrograde trafficking. Consequently, prolonged NM-II inactivation leads to disruption of periodic actin rings and formation of focal axonal swellings, a hallmark of axonal degeneration.
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Affiliation(s)
- Tong Wang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Wei Li
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
- The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Sally Martin
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
- The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Andreas Papadopulos
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Chunxia Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Anmin Jiang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Golnoosh Shamsollahi
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Rumelo Amor
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Vanessa Lanoue
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Frédéric A. Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
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23
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Chiha W, Bartlett CA, Petratos S, Fitzgerald M, Harvey AR. Intravitreal application of AAV-BDNF or mutant AAV-CRMP2 protects retinal ganglion cells and stabilizes axons and myelin after partial optic nerve injury. Exp Neurol 2020; 326:113167. [PMID: 31904385 DOI: 10.1016/j.expneurol.2019.113167] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/20/2019] [Accepted: 12/31/2019] [Indexed: 12/29/2022]
Abstract
Secondary degeneration following an initial injury to the central nervous system (CNS) results in increased tissue loss and is associated with increasing functional impairment. Unilateral partial dorsal transection of the adult rat optic nerve (ON) has proved to be a useful experimental model in which to study factors that contribute to secondary degenerative events. Using this injury model, we here quantified the protective effects of intravitreally administered bi-cistronic adeno-associated viral (AAV2) vectors encoding either brain derived neurotrophic factor (BDNF) or a mutant, phospho-resistant, version of collapsin response mediator protein 2 (CRMP2T555A) on retinal ganglion cells (RGCs), their axons, and associated myelin. To test for potential synergistic interactions, some animals received combined injections of both vectors. Three months post-injury, all treatments maintained RGC numbers in central retina, but only AAV2-BDNF significantly protected ventrally located RGCs exclusively vulnerable to secondary degeneration. Behaviourally, treatments that involved AAV2-BDNF significantly restored the number of smooth-pursuit phases of optokinetic nystagmus. While all therapeutic regimens preserved axonal density and proportions of typical complexes, including heminodes and single nodes, BDNF treatments were generally more effective in maintaining the length of the node of Ranvier in myelin surrounding ventral ON axons after injury. Both AAV2-BDNF and AAV2-CRMP2T555A prevented injury-induced changes in G-ratio and overall myelin thickness, but only AAV2-BDNF administration protected against large-scale myelin decompaction in ventral ON. In summary, in a model of secondary CNS degeneration, both BDNF and CRMP2T555A vectors were neuroprotective, however different efficacies were observed for these overexpressed proteins in the retina and ON, suggesting disparate cellular and molecular targets driving responses for neural repair. The potential use of these vectors to treat other CNS injuries and pathologies is discussed.
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Affiliation(s)
- Wissam Chiha
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Carole A Bartlett
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia
| | - Steven Petratos
- Department of Neuroscience, Monash University, VIC 3004, Australia
| | - Melinda Fitzgerald
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Alan R Harvey
- School of Human Sciences, The University of Western Australia, WA 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia.
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24
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Tribble JR, Vasalauskaite A, Redmond T, Young RD, Hassan S, Fautsch MP, Sengpiel F, Williams PA, Morgan JE. Midget retinal ganglion cell dendritic and mitochondrial degeneration is an early feature of human glaucoma. Brain Commun 2019; 1:fcz035. [PMID: 31894207 PMCID: PMC6928391 DOI: 10.1093/braincomms/fcz035] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is characterized by the progressive dysfunction and loss of retinal ganglion cells. However, the earliest degenerative events that occur in human glaucoma are relatively unknown. Work in animal models has demonstrated that retinal ganglion cell dendrites remodel and atrophy prior to the loss of the cell soma. Whether this occurs in human glaucoma has yet to be elucidated. Serial block face scanning electron microscopy is well established as a method to determine neuronal connectivity at high resolution but so far has only been performed in normal retina from animal models. To assess the structure-function relationship of early human glaucomatous neurodegeneration, regions of inner retina assessed to have none-to-moderate loss of retinal ganglion cell number were processed using serial block face scanning electron microscopy (n = 4 normal retinas, n = 4 glaucoma retinas). This allowed detailed 3D reconstruction of retinal ganglion cells and their intracellular components at a nanometre scale. In our datasets, retinal ganglion cell dendrites degenerate early in human glaucoma, with remodelling and redistribution of the mitochondria. We assessed the relationship between visual sensitivity and retinal ganglion cell density and discovered that this only partially conformed to predicted models of structure-function relationships, which may be affected by these early neurodegenerative changes. In this study, human glaucomatous retinal ganglion cells demonstrate compartmentalized degenerative changes as observed in animal models. Importantly, in these models, many of these changes have been demonstrated to be reversible, increasing the likelihood of translation to viable therapies for human glaucoma.
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Affiliation(s)
- James R Tribble
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | | | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Robert D Young
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Shoaib Hassan
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
| | | | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales, UK
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
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25
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Sele M, Wernitznig S, Lipovšek S, Radulović S, Haybaeck J, Birkl-Toeglhofer AM, Wodlej C, Kleinegger F, Sygulla S, Leoni M, Ropele S, Leitinger G. Optimization of ultrastructural preservation of human brain for transmission electron microscopy after long post-mortem intervals. Acta Neuropathol Commun 2019; 7:144. [PMID: 31481118 PMCID: PMC6724377 DOI: 10.1186/s40478-019-0794-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/24/2019] [Indexed: 12/16/2022] Open
Abstract
Electron microscopy (EM) provides the necessary resolution to visualize the finer structures of nervous tissue morphology, which is important to understand healthy and pathological conditions in the brain. However, for the interpretation of the micrographs the tissue preservation is crucial. The quality of the tissue structure is mostly influenced by the post mortem interval (PMI), the time of death until the preservation of the tissue. Therefore, the aim of this study was to optimize the preparation-procedure for the human frontal lobe to preserve the ultrastructure as well as possible despite the long PMIs. Combining chemical pre- and post-fixation with cryo-fixation and cryo-substitution ("hybrid freezing"), it was possible to improve the preservation of the neuronal profiles of human brain samples compared to the "standard" epoxy resin embedding method. In conclusion short PMIs are generally desirable but up to a PMI of 16 h the ultrastructure can be preserved on an acceptable level with a high contrast using the "hybrid freezing" protocol described here.
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26
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Faiq MA, Wollstein G, Schuman JS, Chan KC. Cholinergic nervous system and glaucoma: From basic science to clinical applications. Prog Retin Eye Res 2019; 72:100767. [PMID: 31242454 PMCID: PMC6739176 DOI: 10.1016/j.preteyeres.2019.06.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 02/08/2023]
Abstract
The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.
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Affiliation(s)
- Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Joel S Schuman
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, United States.
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27
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Lee HH, Yaros K, Veraart J, Pathan JL, Liang FX, Kim SG, Novikov DS, Fieremans E. Along-axon diameter variation and axonal orientation dispersion revealed with 3D electron microscopy: implications for quantifying brain white matter microstructure with histology and diffusion MRI. Brain Struct Funct 2019; 224:1469-1488. [PMID: 30790073 PMCID: PMC6510616 DOI: 10.1007/s00429-019-01844-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 02/01/2019] [Indexed: 10/27/2022]
Abstract
Tissue microstructure modeling of diffusion MRI signal is an active research area striving to bridge the gap between macroscopic MRI resolution and cellular-level tissue architecture. Such modeling in neuronal tissue relies on a number of assumptions about the microstructural features of axonal fiber bundles, such as the axonal shape (e.g., perfect cylinders) and the fiber orientation dispersion. However, these assumptions have not yet been validated by sufficiently high-resolution 3-dimensional histology. Here, we reconstructed sequential scanning electron microscopy images in mouse brain corpus callosum, and introduced a random-walker (RaW)-based algorithm to rapidly segment individual intra-axonal spaces and myelin sheaths of myelinated axons. Confirmed by a segmentation based on human annotations initiated with conventional machine-learning-based carving, our semi-automatic algorithm is reliable and less time-consuming. Based on the segmentation, we calculated MRI-relevant estimates of size-related parameters (inner axonal diameter, its distribution, along-axon variation, and myelin g-ratio), and orientation-related parameters (fiber orientation distribution and its rotational invariants; dispersion angle). The reported dispersion angle is consistent with previous 2-dimensional histology studies and diffusion MRI measurements, while the reported diameter exceeds those in other mouse brain studies. Furthermore, we calculated how these quantities would evolve in actual diffusion MRI experiments as a function of diffusion time, thereby providing a coarse-graining window on the microstructure, and showed that the orientation-related metrics have negligible diffusion time-dependence over clinical and pre-clinical diffusion time ranges. However, the MRI-measured inner axonal diameters, dominated by the widest cross sections, effectively decrease with diffusion time by ~ 17% due to the coarse-graining over axonal caliber variations. Furthermore, our 3d measurement showed that there is significant variation of the diameter along the axon. Hence, fiber orientation dispersion estimated from MRI should be relatively stable, while the "apparent" inner axonal diameters are sensitive to experimental settings, and cannot be modeled by perfectly cylindrical axons.
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Affiliation(s)
- Hong-Hsi Lee
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA.
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA.
| | - Katarina Yaros
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
| | - Jelle Veraart
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
| | - Jasmine L Pathan
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
| | - Feng-Xia Liang
- Department of Cell Biology and Microscopy Core, New York University School of Medicine, 540 First Avenue, New York, NY, 10016, USA
| | - Sungheon G Kim
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
| | - Dmitry S Novikov
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
| | - Els Fieremans
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, 660 First Avenue, New York, NY, 10016, USA
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28
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Li HY, Huang M, Luo QY, Hong X, Ramakrishna S, So KF. Lycium barbarum (Wolfberry) Increases Retinal Ganglion Cell Survival and Affects both Microglia/Macrophage Polarization and Autophagy after Rat Partial Optic Nerve Transection. Cell Transplant 2019; 28:607-618. [PMID: 30838886 PMCID: PMC7103598 DOI: 10.1177/0963689719835181] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rat partial optic nerve transection (PONT) model has been used for studying secondary
degeneration of retinal ganglion cells (RGCs) in recent years. In this study, we carried
out PONT of the temporal side of rat optic nerves, whereas PONT was carried out of the
superior side in the previous publication. We found that this surgery is better and easier
than the previous method and can produce a repeatable and reliable model. We detected
significant changes in the polarization of microglia/macrophages and the level of
autophagy in optic nerves after PONT. We also used this model to detect the effects of the
polysaccharides extracted from Lycium barbarum (LBP) on the survival of
RGCs and the changes in the polarization of microglia/macrophages and the level of
autophagy after PONT. We find that LBP can delay secondary degeneration of RGCs after
temporal injury of optic nerves, promote the M2 polarization of microglia/macrophages, and
down-regulate the level of autophagy after PONT. In conclusion, we find that the
polarization of microglia/macrophages and the autophagy level change after PONT; LBP
treatment delays secondary degeneration of RGCs; and the polarization of
microglia/macrophages and the level of autophagy are also altered after LBP treatment.
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Affiliation(s)
- Hong-Ying Li
- 1 Department of Anatomy, Medical School, Jinan University, Guangzhou, China.,2 Collaborative Joint Laboratory, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration, Jinan University, Guangzhou, China.,3 Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Mi Huang
- 2 Collaborative Joint Laboratory, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration, Jinan University, Guangzhou, China.,3 Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Qiu-Yan Luo
- 1 Department of Anatomy, Medical School, Jinan University, Guangzhou, China
| | - Xi Hong
- 1 Department of Anatomy, Medical School, Jinan University, Guangzhou, China.,2 Collaborative Joint Laboratory, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration, Jinan University, Guangzhou, China.,3 Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Seeram Ramakrishna
- 2 Collaborative Joint Laboratory, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration, Jinan University, Guangzhou, China
| | - Kwok-Fai So
- 2 Collaborative Joint Laboratory, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration, Jinan University, Guangzhou, China.,3 Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China.,4 Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, China.,5 State Key Laboratory of Brain and Cognitive Sciences and Department of Ophthalmology, The University of Hong Kong, Hong Kong, China
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Bai X, Chen B, Yang F, Liu X, Silva-Nunes D, Robinson I. Three-dimensional imaging and analysis of the internal structure of SAPO-34 zeolite crystals. RSC Adv 2018; 8:33631-33636. [PMID: 35548840 PMCID: PMC9086581 DOI: 10.1039/c8ra05918g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/22/2018] [Indexed: 01/03/2023] Open
Abstract
SAPO-34 is widely used as a catalyst for important industrial reactions, such as the methanol-to-olefin (MTO) reaction and selective catalytic reduction (SCR) of nitrogen oxides (NOx). The internal structure of SAPO-34 has a great influence on the catalytic performance. Two-dimensional (2D) images of the SAPO-34 particle surfaces from scanning electron microscopy (SEM) show clearly well-faceted cube morphologies, which suggest they should be quite uniform perfect crystals. However, Bragg coherent X-ray diffraction imaging (BCDI) of the SAPO-34 particles shows a rich internal structure existing within these crystals. In this work, we investigated the internal structure of a SAPO-34 zeolite by serial block-face scanning electron microscopy (SBFSEM). The internal structure observed in the backscattered electron (BSE) micrographs from SBFSEM and the energy dispersive spectroscopy (EDS) measurements is found to be consistent with the BCDI results. From the three-dimensional (3D) structural images of SAPO-34 crystals obtained by SBFSEM, the domains within the individual SAPO-34 were visualized and quantified. This work studies the inter-structure of a SAPO-34 particle by Bragg coherent X-ray diffraction imaging and serial-block-face scanning electron microscopy.![]()
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Affiliation(s)
- Xue Bai
- School of Materials Science and Engineering
- Tongji University
- Shanghai 201804
- China
| | - Bo Chen
- School of Materials Science and Engineering
- Tongji University
- Shanghai 201804
- China
- London Centre for Nanotechnology
| | - Fei Yang
- School of Materials Science and Engineering
- Tongji University
- Shanghai 201804
- China
| | - Xianping Liu
- School of Materials Science and Engineering
- Tongji University
- Shanghai 201804
- China
| | - Daniel Silva-Nunes
- Division of Condensed Matter Physics and Materials Science
- Brookhaven National Laboratory
- NY 11973
- USA
| | - Ian Robinson
- School of Materials Science and Engineering
- Tongji University
- Shanghai 201804
- China
- London Centre for Nanotechnology
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