1
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Ames S, Adams K, Geisen ME, Stirling DP. Ca 2+-induced myelin pathology precedes axonal spheroid formation and is mediated in part by store-operated Ca 2+ entry after spinal cord injury. Neural Regen Res 2023; 18:2720-2726. [PMID: 37449636 DOI: 10.4103/1673-5374.373656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
The formation of axonal spheroid is a common feature following spinal cord injury. To further understand the source of Ca2+ that mediates axonal spheroid formation, we used our previously characterized ex vivo mouse spinal cord model that allows precise perturbation of extracellular Ca2+. We performed two-photon excitation imaging of spinal cords isolated from Thy1YFP+ transgenic mice and applied the lipophilic dye, Nile red, to record dynamic changes in dorsal column axons and their myelin sheaths respectively. We selectively released Ca2+ from internal stores using the Ca2+ ionophore ionomycin in the presence or absence of external Ca2+. We reported that ionomycin dose-dependently induces pathological changes in myelin and pronounced axonal spheroid formation in the presence of normal 2 mM Ca2+ artificial cerebrospinal fluid. In contrast, removal of external Ca2+ significantly decreased ionomycin-induced myelin and axonal spheroid formation at 2 hours but not at 1 hour after treatment. Using mice that express a neuron-specific Ca2+ indicator in spinal cord axons, we confirmed that ionomycin induced significant increases in intra-axonal Ca2+, but not in the absence of external Ca2+. Periaxonal swelling and the resultant disruption in the axo-myelinic interface often precedes and is negatively correlated with axonal spheroid formation. Pretreatment with YM58483 (500 nM), a well-established blocker of store-operated Ca2+ entry, significantly decreased myelin injury and axonal spheroid formation. Collectively, these data reveal that ionomycin-induced depletion of internal Ca2+ stores and subsequent external Ca2+ entry through store-operated Ca2+ entry contributes to pathological changes in myelin and axonal spheroid formation, providing new targets to protect central myelinated fibers.
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Affiliation(s)
- Spencer Ames
- Kentucky Spinal Cord Injury Research Center; Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY, USA
| | - Kia Adams
- Kentucky Spinal Cord Injury Research Center; Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY, USA
| | - Mariah E Geisen
- Kentucky Spinal Cord Injury Research Center; Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY, USA
| | - David P Stirling
- Kentucky Spinal Cord Injury Research Center; Department of Neurological Surgery; Anatomical Sciences and Neurobiology; Microbiology and Immunology, University of Louisville, School of Medicine, Louisville, KY, USA
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2
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Vadisiute A, Meijer E, Szabó F, Hoerder-Suabedissen A, Kawashita E, Hayashi S, Molnár Z. The role of snare proteins in cortical development. Dev Neurobiol 2022; 82:457-475. [PMID: 35724379 PMCID: PMC9539872 DOI: 10.1002/dneu.22892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/18/2022] [Accepted: 05/25/2022] [Indexed: 12/01/2022]
Abstract
Neural communication in the adult nervous system is mediated primarily through chemical synapses, where action potentials elicit Ca2+ signals, which trigger vesicular fusion and neurotransmitter release in the presynaptic compartment. At early stages of development, the brain is shaped by communication via trophic factors and other extracellular signaling, and by contact-mediated cell-cell interactions including chemical synapses. The patterns of early neuronal impulses and spontaneous and regulated neurotransmitter release guide the precise topography of axonal projections and contribute to determining cell survival. The study of the role of specific proteins of the synaptic vesicle release machinery in the establishment, plasticity, and maintenance of neuronal connections during development has only recently become possible, with the advent of mouse models where various members of the N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex have been genetically manipulated. We provide an overview of these models, focusing on the role of regulated vesicular release and/or cellular excitability in synaptic assembly, development and maintenance of cortical circuits, cell survival, circuit level excitation-inhibition balance, myelination, refinement, and plasticity of key axonal projections from the cerebral cortex. These models are important for understanding various developmental and psychiatric conditions, and neurodegenerative diseases.
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Affiliation(s)
- Auguste Vadisiute
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Elise Meijer
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Florina Szabó
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Anna Hoerder-Suabedissen
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Eri Kawashita
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan
| | - Shuichi Hayashi
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
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3
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Tsutsui S, Morgan M, Tedford H, You H, Zamponi GW, Stys PK. Copper ions, prion protein and Aβ modulate Ca levels in central nervous system myelin in an NMDA receptor-dependent manner. Mol Brain 2022; 15:67. [PMID: 35883145 PMCID: PMC9327403 DOI: 10.1186/s13041-022-00955-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 07/12/2022] [Indexed: 11/10/2022] Open
Abstract
As in neurons, CNS myelin expresses N-Methyl-D-Aspartate Receptors (NMDARs) that subserve physiological roles, but have the potential to induce injury to this vital element. Using 2-photon imaging of myelinic Ca in live ex vivo mouse optic nerves, we show that Cu ions potently modulate Ca levels in an NMDAR-dependent manner. Chelating Cu in the perfusate induced a substantial increase in Ca levels, and also caused significant axo-myelinic injury. Myelinic NMDARs are shown to be regulated by cellular prion protein; only in prion protein KO optic nerves does application of NMDA + D-serine induce a large Ca increase, consistent with strong desensitization of these receptors in the presence of prion protein limiting Ca overload. Aβ1-42 peptide induced a large Ca increase that was also Cu-dependent, and was blocked by NMDAR antagonism. Our results indicate that like in neurons, myelinic NMDARs permeate potentially injurious amounts of Ca, and are also potently regulated by micromolar Cu and activated by Aβ1-42 peptides. These findings shed mechanistic light on the important primary white matter injury frequently observed in Alzheimer's brain.
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Affiliation(s)
- Shigeki Tsutsui
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Megan Morgan
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Hugo Tedford
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Haitao You
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Peter K Stys
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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4
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Ali M, Zhang X, LaCanna R, Tomar D, Elrod JW, Tian Y. MICU1-dependent mitochondrial calcium uptake regulates lung alveolar type 2 cell plasticity and lung regeneration. JCI Insight 2022; 7:154447. [PMID: 35050901 PMCID: PMC8876408 DOI: 10.1172/jci.insight.154447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/05/2022] [Indexed: 11/29/2022] Open
Abstract
Lung alveolar type 2 (AT2) cells are progenitors for alveolar type 1 (AT1) cells. Although many factors regulate AT2 cell plasticity, the role of mitochondrial calcium (mCa2+) uptake in controlling AT2 cells remains unclear. We previously identified that the miR-302 family supports lung epithelial progenitor cell proliferation and less differentiated phenotypes during development. Here, we report that a sustained elevation of miR-302 in adult AT2 cells decreases AT2-to-AT1 cell differentiation during the Streptococcus pneumoniae–induced lung injury repair. We identified that miR-302 targets and represses the expression of mitochondrial Ca2+ uptake 1 (MICU1), which regulates mCa2+ uptake through the mCa2+ uniporter channel by acting as a gatekeeper at low cytosolic Ca2+ levels. Our results reveal a marked increase in MICU1 protein expression and decreased mCa2+ uptake during AT2-to-AT1 cell differentiation in the adult lung. Deletion of Micu1 in AT2 cells reduces AT2-to-AT1 cell differentiation during steady-state tissue maintenance and alveolar epithelial regeneration after bacterial pneumonia. These studies indicate that mCa2+ uptake is extensively modulated during AT2-to-AT1 cell differentiation and that MICU1-dependent mCa2+ uniporter channel gating is a prominent mechanism modulating AT2-to-AT1 cell differentiation.
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Affiliation(s)
- Mir Ali
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
| | - Xiaoying Zhang
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
| | - Ryan LaCanna
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
| | - Dhanendra Tomar
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
| | - John W Elrod
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
| | - Ying Tian
- Department of Cardiovascular Sciences, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, United States of America
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5
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Heflin JK, Sun W. Novel Toolboxes for the Investigation of Activity-Dependent Myelination in the Central Nervous System. Front Cell Neurosci 2021; 15:769809. [PMID: 34795563 PMCID: PMC8592894 DOI: 10.3389/fncel.2021.769809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
Myelination is essential for signal processing within neural networks. Emerging data suggest that neuronal activity positively instructs myelin development and myelin adaptation during adulthood. However, the underlying mechanisms controlling activity-dependent myelination have not been fully elucidated. Myelination is a multi-step process that involves the proliferation and differentiation of oligodendrocyte precursor cells followed by the initial contact and ensheathment of axons by mature oligodendrocytes. Conventional end-point studies rarely capture the dynamic interaction between neurons and oligodendrocyte lineage cells spanning such a long temporal window. Given that such interactions and downstream signaling cascades are likely to occur within fine cellular processes of oligodendrocytes and their precursor cells, overcoming spatial resolution limitations represents another technical hurdle in the field. In this mini-review, we discuss how advanced genetic, cutting-edge imaging, and electrophysiological approaches enable us to investigate neuron-oligodendrocyte lineage cell interaction and myelination with both temporal and spatial precision.
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Affiliation(s)
- Jack Kent Heflin
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Wenjing Sun
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
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6
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Panthee N, Ono M, Yamamoto T, Ikemura M, Tanaka T, Itoda Y, Suzuki H. Evaluation of spinal cord protective threshold of serum memantine, an NMDA receptor antagonist, in a rabbit model of paraplegia. Indian J Thorac Cardiovasc Surg 2020; 36:598-607. [PMID: 33100621 DOI: 10.1007/s12055-020-01026-8] [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: 05/14/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 11/27/2022] Open
Abstract
Purpose To evaluate the threshold of serum memantine for prevention of spinal cord injury (SCI) in a rabbit paraplegic model. Methods Forty-two New Zealand white rabbits were divided into 7 groups. Preoperatively, oral memantine was given starting from 60 mg OD for 7 days in the initial group, then reducing the dose and/or duration to 60 mg OD for 5 days, 30 mg OD for 5 days, 30 mg OD for 3 days, 15 mg OD for 3 days, 30 mg single dose, and 60 mg single dose, in subsequent 6 groups. A paraplegic model was created by clamping both infrarenal aorta and inferior vena cava (IVC) for 45 min. Motor evoked potentials (MEPs), modified Tarlov score (0-5), serum memantine concentration, and histopathology of the spinal cord were evaluated. Results Half of all rabbits (21/42) showed spinal protection. Receiver operating characteristic (ROC) curve analysis showed serum level of 4.5 ng/ml as a cutoff value for spinal protection (sensitivity 86%, specificity 62%, area under the curve (AUC) 0.785, P = .002). Sixteen rabbits had serum level ≥ 4.5 ng/ml (group A), with 26 rabbits having < 4.5 ng/ml (group B). Further comparison was done between groups A and B. The mean modified Tarlov score at 6, 24, 48, and 72 h was 4.5 ± 0.9 and 2.4 ± 1.6, in groups A and B, respectively (P < .001). The modified Tarlov score showed positive correlation with serum memantine level (Spearman's rho = 0.618, P = .01). Results of MEP and histopathology were significantly better for group A. Conclusions We showed that memantine is protective against SCI at serum levels ≥ 4.5 ng/ml in a rabbit model; thus, it can be a potential adjunct for spinal protection during thoracic/thoracoabdominal aortic surgeries.
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Affiliation(s)
- Nirmal Panthee
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Minoru Ono
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Takehito Yamamoto
- Department of Pharmacy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Masako Ikemura
- Department of Neuropathology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Tsuruhito Tanaka
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Yoshifumi Itoda
- Department of Cardiac Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
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7
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Belov Kirdajova D, Kriska J, Tureckova J, Anderova M. Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells. Front Cell Neurosci 2020; 14:51. [PMID: 32265656 PMCID: PMC7098326 DOI: 10.3389/fncel.2020.00051] [Citation(s) in RCA: 171] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca2+) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca2+ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca2+-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.
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Affiliation(s)
- Denisa Belov Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
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8
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Abstract
Cells of the oligodendrocyte lineage express a wide range of Ca2+ channels and receptors that regulate oligodendrocyte progenitor cell (OPC) and oligodendrocyte formation and function. Here we define those key channels and receptors that regulate Ca2+ signaling and OPC development and myelination. We then discuss how the regulation of intracellular Ca2+ in turn affects OPC and oligodendrocyte biology in the healthy nervous system and under pathological conditions. Activation of Ca2+ channels and receptors in OPCs and oligodendrocytes by neurotransmitters converges on regulating intracellular Ca2+, making Ca2+ signaling a central candidate mediator of activity-driven myelination. Indeed, recent evidence indicates that localized changes in Ca2+ in oligodendrocytes can regulate the formation and remodeling of myelin sheaths and perhaps additional functions of oligodendrocytes and OPCs. Thus, decoding how OPCs and myelinating oligodendrocytes integrate and process Ca2+ signals will be important to fully understand central nervous system formation, health, and function.
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Affiliation(s)
- Pablo M Paez
- Department of Pharmacology and Toxicology and Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, New York 14203, USA;
| | - David A Lyons
- Centre for Discovery Brain Sciences, Centre for Multiple Sclerosis Research, and Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom;
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9
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Simultaneous Determination of Glutamate and Calcium Ion in Rat Brain during Spreading Depression and Ischemia Processes. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2019. [DOI: 10.1016/s1872-2040(19)61146-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Hackett TA. Adenosine A 1 Receptor mRNA Expression by Neurons and Glia in the Auditory Forebrain. Anat Rec (Hoboken) 2018; 301:1882-1905. [PMID: 30315630 PMCID: PMC6282551 DOI: 10.1002/ar.23907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/05/2017] [Accepted: 01/10/2018] [Indexed: 12/30/2022]
Abstract
In the brain, purines such as ATP and adenosine can function as neurotransmitters and co‐transmitters, or serve as signals in neuron–glial interactions. In thalamocortical (TC) projections to sensory cortex, adenosine functions as a negative regulator of glutamate release via activation of the presynaptic adenosine A1 receptor (A1R). In the auditory forebrain, restriction of A1R‐adenosine signaling in medial geniculate (MG) neurons is sufficient to extend LTP, LTD, and tonotopic map plasticity in adult mice for months beyond the critical period. Interfering with adenosine signaling in primary auditory cortex (A1) does not contribute to these forms of plasticity, suggesting regional differences in the roles of A1R‐mediated adenosine signaling in the forebrain. To advance understanding of the circuitry, in situ hybridization was used to localize neuronal and glial cell types in the auditory forebrain that express A1R transcripts (Adora1), based on co‐expression with cell‐specific markers for neuronal and glial subtypes. In A1, Adora1 transcripts were concentrated in L3/4 and L6 of glutamatergic neurons. Subpopulations of GABAergic neurons, astrocytes, oligodendrocytes, and microglia expressed lower levels of Adora1. In MG, Adora1 was expressed by glutamatergic neurons in all divisions, and subpopulations of all glial classes. The collective findings imply that A1R‐mediated signaling broadly extends to all subdivisions of auditory cortex and MG. Selective expression by neuronal and glial subpopulations suggests that experimental manipulations of A1R‐adenosine signaling could impact several cell types, depending on their location. Strategies to target Adora1 in specific cell types can be developed from the data generated here. Anat Rec, 301:1882–1905, 2018. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
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Affiliation(s)
- Troy A Hackett
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
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11
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Doyle S, Hansen DB, Vella J, Bond P, Harper G, Zammit C, Valentino M, Fern R. Vesicular glutamate release from central axons contributes to myelin damage. Nat Commun 2018. [PMID: 29531223 PMCID: PMC5847599 DOI: 10.1038/s41467-018-03427-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The axon myelin sheath is prone to injury associated with N-methyl-d-aspartate (NMDA)-type glutamate receptor activation but the source of glutamate in this context is unknown. Myelin damage results in permanent action potential loss and severe functional deficit in the white matter of the CNS, for example in ischemic stroke. Here, we show that in rats and mice, ischemic conditions trigger activation of myelinic NMDA receptors incorporating GluN2C/D subunits following release of axonal vesicular glutamate into the peri-axonal space under the myelin sheath. Glial sources of glutamate such as reverse transport did not contribute significantly to this phenomenon. We demonstrate selective myelin uptake and retention of a GluN2C/D NMDA receptor negative allosteric modulator that shields myelin from ischemic injury. The findings potentially support a rational approach toward a low-impact prophylactic therapy to protect patients at risk of stroke and other forms of excitotoxic injury. Neuronal activity can lead to vesicular release of glutamate. Here the authors demonstrate that vesicular release of glutamate occurs in axons during ischemic conditions, and that an allosteric modulator of GluN2C/D is protective in models of ischemic injury.
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Affiliation(s)
- Sean Doyle
- University of Plymouth, Plymouth, PL6 8BY, UK
| | | | | | - Peter Bond
- University of Plymouth, Plymouth, PL6 8BY, UK
| | | | | | | | - Robert Fern
- University of Plymouth, Plymouth, PL6 8BY, UK.
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12
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Wang Z, Cui S, Qiu S, Pu S. A highly selective fluorescence “turn-on” sensor for Ca2+ based on diarylethene with a triazozoyl hydrazine unit. RSC Adv 2018; 8:29295-29300. [PMID: 35548020 PMCID: PMC9084557 DOI: 10.1039/c8ra06039h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/10/2018] [Indexed: 12/26/2022] Open
Abstract
A new photochromic diarylethene derivative with a triazozoyl hydrazine unit has been designed and synthesized.
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Affiliation(s)
- Zhen Wang
- Jiangxi Key Laboratory of Organic Chemistry
- Jiangxi Science and Technology Normal University
- Nanchang 330013
- PR China
| | - Shiqiang Cui
- Jiangxi Key Laboratory of Organic Chemistry
- Jiangxi Science and Technology Normal University
- Nanchang 330013
- PR China
| | - Shouyu Qiu
- Jiangxi Key Laboratory of Organic Chemistry
- Jiangxi Science and Technology Normal University
- Nanchang 330013
- PR China
| | - Shouzhi Pu
- Jiangxi Key Laboratory of Organic Chemistry
- Jiangxi Science and Technology Normal University
- Nanchang 330013
- PR China
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13
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Axo-myelinic neurotransmission: a novel mode of cell signalling in the central nervous system. Nat Rev Neurosci 2017; 19:49-58. [PMID: 29118449 DOI: 10.1038/nrn.2017.128] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is widely recognized that myelination of axons greatly enhances the speed of signal transmission. An exciting new finding is the dynamic communication between axons and their myelin-forming oligodendrocytes, including activity-dependent signalling from axon to myelin. The oligodendrocyte-myelin complex may in turn respond by providing metabolic support or alter subtle myelin properties to modulate action potential propagation. In this Opinion, we discuss what is known regarding the molecular physiology of this novel, synapse-like communication and speculate on potential roles in disease states including multiple sclerosis, schizophrenia and Alzheimer disease. An emerging appreciation of the contribution of white-matter perturbations to neurological dysfunction identifies the axo-myelinic synapse as a potential novel therapeutic target.
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14
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Cao Y, Wang X, Shi X, Clee SM, McGeer PL, Wolf MO, Orvig C. Biological Imaging with Medium-Sensitive Bichromatic Flexible Fluorescent Dyes. Angew Chem Int Ed Engl 2017; 56:15603-15606. [DOI: 10.1002/anie.201708529] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/10/2017] [Indexed: 01/14/2023]
Affiliation(s)
- Yang Cao
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Xiaozhu Wang
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Xiaolei Shi
- The Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver British Columbia Canada
| | - Susanne M. Clee
- Canada Research Chair in the Genetics of Obesity and Diabetes, Department of Cellular and Physiological Sciences; University of British Columbia; Vancouver British Columbia Canada
| | - Patrick L. McGeer
- The Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver British Columbia Canada
| | - Michael O. Wolf
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Chris Orvig
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
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15
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Cao Y, Wang X, Shi X, Clee SM, McGeer PL, Wolf MO, Orvig C. Biological Imaging with Medium-Sensitive Bichromatic Flexible Fluorescent Dyes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708529] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yang Cao
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Xiaozhu Wang
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Xiaolei Shi
- The Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver British Columbia Canada
| | - Susanne M. Clee
- Canada Research Chair in the Genetics of Obesity and Diabetes, Department of Cellular and Physiological Sciences; University of British Columbia; Vancouver British Columbia Canada
| | - Patrick L. McGeer
- The Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver British Columbia Canada
| | - Michael O. Wolf
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
| | - Chris Orvig
- Department of Chemistry; University of British Columbia; Vancouver British Columbia Canada
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16
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Pan S, Tang H, Song Z, Li J, Guo Y. A Novel Dual Channel Fluorescent Probe for Ca2+
and Zn2+
Based on a Coumarin Schiff Base. CHINESE J CHEM 2017. [DOI: 10.1002/cjoc.201600923] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shengnan Pan
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education; College of Chemistry and Materials Science, Northwest University; Xi'an Shaanxi 710127 China
| | - Haoyang Tang
- School of Automation; Xi'an University of Posts and Telecommunications; Xi'an Shaanxi 710121 China
| | - Zhanke Song
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education; College of Chemistry and Materials Science, Northwest University; Xi'an Shaanxi 710127 China
| | - Jin Li
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education; College of Chemistry and Materials Science, Northwest University; Xi'an Shaanxi 710127 China
| | - Yuan Guo
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education; College of Chemistry and Materials Science, Northwest University; Xi'an Shaanxi 710127 China
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17
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Zhang H, Yin C, Liu T, Zhang Y, Huo F. "Turn-on" fluorescent probe detection of Ca 2+ ions and applications to bioimaging. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 180:211-216. [PMID: 28301823 DOI: 10.1016/j.saa.2017.03.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/24/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
Ca2+ is intracellular divalent cation with the largest concentration variations and involved in many biological phenomena and often acted as a second messenger in signaling pathway. Therefore, the development of probes for specific Ca2+ detection is of great importance. Herein, a novel turn-on fluorescent probe for the detection of Ca2+ in MeCN-aqueous medium was designed and synthesized. The probe displayed responses to Ca2+ with a fluorescence enhancement at 525nm, accompanying with a distinct fluorescence change from nearly colorless to bright yellow-green. Besides, the probe exhibited a rapid signal response time (within 25s), a good linearity range and a lower detection limit (2.70×10-7M). In addition, the ability of the probe to detect Ca2+ in living cells (HeLa cells) via an enhancement of the fluorescence has also been demonstrated.
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Affiliation(s)
- Huifang Zhang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Caixia Yin
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
| | - Tao Liu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Yongbin Zhang
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China
| | - Fangjun Huo
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China.
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18
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Micu I, Brideau C, Lu L, Stys PK. Effects of laser polarization on responses of the fluorescent Ca 2+ indicator X-Rhod-1 in neurons and myelin. NEUROPHOTONICS 2017; 4:025002. [PMID: 28612034 PMCID: PMC5459219 DOI: 10.1117/1.nph.4.2.025002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/15/2017] [Indexed: 05/05/2023]
Abstract
Laser-scanning optical microscopes generally do not control the polarization of the exciting laser field. We show that laser polarization and imaging mode (confocal versus two photon) exert a profound influence on the ability to detect [Formula: see text] changes in both cultured neurons and living myelin. With two-photon excitation, increasing ellipticity resulted in a [Formula: see text] reduction in resting X-Rhod-1 fluorescence in homogeneous bulk solution, cell cytoplasm, and myelin. In contrast, varying the angle of a linearly polarized laser field only had appreciable effects on dyes that partitioned into myelin in an ordered manner. During injury-induced [Formula: see text] increases, larger ellipticities resulted in a significantly greater injury-induced signal increase in neurons, and particularly in myelin. Indeed, the traditional method of measuring [Formula: see text] changes using one-photon confocal mode with linearly polarized continuous wave laser illumination produced no appreciable X-Rhod-1 signal increase in ischemic myelin, compared to a robust [Formula: see text] fluorescence increase with two-photon excitation and optimized ellipticity with the identical injury paradigm. This underscores the differences in one- versus two-photon excitation and, in particular, the under-appreciated effects of laser polarization on the behavior of certain [Formula: see text] reporters, which may lead to substantial underestimates of the real [Formula: see text] fluctuations in various cellular compartments.
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Affiliation(s)
- Ileana Micu
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Craig Brideau
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Li Lu
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Peter K. Stys
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- Address all correspondence to: Peter K. Stys, E-mail:
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19
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Plemel JR, Caprariello AV, Keough MB, Henry TJ, Tsutsui S, Chu TH, Schenk GJ, Klaver R, Yong VW, Stys PK. Unique spectral signatures of the nucleic acid dye acridine orange can distinguish cell death by apoptosis and necroptosis. J Cell Biol 2017; 216:1163-1181. [PMID: 28264914 PMCID: PMC5379938 DOI: 10.1083/jcb.201602028] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 10/24/2016] [Accepted: 01/12/2017] [Indexed: 11/22/2022] Open
Abstract
Cellular injury and death are ubiquitous features of disease, yet tools to detect them are limited and insensitive to subtle pathological changes. Acridine orange (AO), a nucleic acid dye with unique spectral properties, enables real-time measurement of RNA and DNA as proxies for cell viability during exposure to various noxious stimuli. This tool illuminates spectral signatures unique to various modes of cell death, such as cells undergoing apoptosis versus necrosis/necroptosis. This new approach also shows that cellular RNA decreases during necrotic, necroptotic, and apoptotic cell death caused by demyelinating, ischemic, and traumatic injuries, implying its involvement in a wide spectrum of tissue pathologies. Furthermore, cells with pathologically low levels of cytoplasmic RNA are detected earlier and in higher numbers than with standard markers including TdT-mediated dUTP biotin nick-end labeling and cleaved caspase 3 immunofluorescence. Our technique highlights AO-labeled cytoplasmic RNA as an important early marker of cellular injury and a sensitive indicator of various modes of cell death in a range of experimental models.
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Affiliation(s)
- Jason R Plemel
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Andrew V Caprariello
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Michael B Keough
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Tyler J Henry
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Shigeki Tsutsui
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Tak H Chu
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Geert J Schenk
- Department of Anatomy and Neurosciences, VU University Medical Center, 1081 HV Amsterdam, Netherlands
| | - Roel Klaver
- Department of Anatomy and Neurosciences, VU University Medical Center, 1081 HV Amsterdam, Netherlands
| | - V Wee Yong
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Peter K Stys
- Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
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20
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Christensen PC, Welch NC, Brideau C, Stys PK. Functional ionotropic glutamate receptors on peripheral axons and myelin. Muscle Nerve 2016; 54:451-9. [DOI: 10.1002/mus.25078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/26/2016] [Accepted: 02/10/2016] [Indexed: 01/22/2023]
Affiliation(s)
- Pia Crone Christensen
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, 3330 Hospital Drive NW, University of Calgary; Calgary Alberta Canada T2N 4N1
| | - Nicole Cheryl Welch
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, 3330 Hospital Drive NW, University of Calgary; Calgary Alberta Canada T2N 4N1
| | - Craig Brideau
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, 3330 Hospital Drive NW, University of Calgary; Calgary Alberta Canada T2N 4N1
| | - Peter K. Stys
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, 3330 Hospital Drive NW, University of Calgary; Calgary Alberta Canada T2N 4N1
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21
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Baraban M, Mensch S, Lyons DA. Adaptive myelination from fish to man. Brain Res 2016; 1641:149-161. [PMID: 26498877 PMCID: PMC4907128 DOI: 10.1016/j.brainres.2015.10.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 01/06/2023]
Abstract
Myelinated axons with nodes of Ranvier are an evolutionary elaboration common to essentially all jawed vertebrates. Myelin made by Schwann cells in our peripheral nervous system and oligodendrocytes in our central nervous system has been long known to facilitate rapid energy efficient nerve impulse propagation. However, it is now also clear, particularly in the central nervous system, that myelin is not a simple static insulator but that it is dynamically regulated throughout development and life. New myelin sheaths can be made by newly differentiating oligodendrocytes, and mature myelin sheaths can be stimulated to grow again in the adult. Furthermore, numerous studies in models from fish to man indicate that neuronal activity can affect distinct stages of oligodendrocyte development and the process of myelination itself. This begs questions as to how these effects of activity are mediated at a cellular and molecular level and whether activity-driven adaptive myelination is a feature common to all myelinated axons, or indeed all oligodendrocytes, or is specific to cells or circuits with particular functions. Here we review the recent literature on this topic, elaborate on the key outstanding questions in the field, and look forward to future studies that incorporate investigations in systems from fish to man that will provide further insight into this fundamental aspect of nervous system plasticity. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Marion Baraban
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sigrid Mensch
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - David A Lyons
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
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22
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Hirabayashi K, Hanaoka K, Egawa T, Kobayashi C, Takahashi S, Komatsu T, Ueno T, Terai T, Ikegaya Y, Nagano T, Urano Y. Development of practical red fluorescent probe for cytoplasmic calcium ions with greatly improved cell-membrane permeability. Cell Calcium 2016; 60:256-65. [PMID: 27349490 DOI: 10.1016/j.ceca.2016.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/04/2016] [Accepted: 06/07/2016] [Indexed: 01/26/2023]
Abstract
Fluorescence imaging of calcium ions (Ca(2+)) has become an essential technique for investigation of signaling pathways involving Ca(2+) as a second messenger. But, Ca(2+) signaling is involved in many biological phenomena, and therefore simultaneous visualization of Ca(2+) and other biomolecules (multicolor imaging) would be particularly informative. For this purpose, we set out to develop a fluorescent probe for Ca(2+) that would operate in a different color region (red) from that of probes for other molecules, many of which show green fluorescence, as exemplified by green fluorescent protein (GFP). We previously developed a red fluorescent probe for monitoring cytoplasmic Ca(2+) concentration, based on our established red fluorophore, TokyoMagenta (TM), but there remained room for improvement, especially as regards efficiency of introduction into cells. We considered that this issue was probably mainly due to limited water solubility of the probe. So, we designed and synthesized a red-fluorescent probe with improved water solubility. We confirmed that this Ca(2+) red-fluorescent probe showed high cell-membrane permeability with bright fluorescence. It was successfully applied to fluorescence imaging of not only live cells, but also brain slices, and should be practically useful for multicolor imaging studies of biological mechanisms.
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Affiliation(s)
- Kazuhisa Hirabayashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenjiro Hanaoka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takahiro Egawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Chiaki Kobayashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shodai Takahashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toru Komatsu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Tasuku Ueno
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takuya Terai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tetsuo Nagano
- Drug Discovery Initiative, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yasuteru Urano
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; CREST, AMED, Saitama 332-0012, Japan.
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23
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Miyata S, Taniguchi M, Koyama Y, Shimizu S, Tanaka T, Yasuno F, Yamamoto A, Iida H, Kudo T, Katayama T, Tohyama M. Association between chronic stress-induced structural abnormalities in Ranvier nodes and reduced oligodendrocyte activity in major depression. Sci Rep 2016; 6:23084. [PMID: 26976207 PMCID: PMC4791682 DOI: 10.1038/srep23084] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 02/25/2016] [Indexed: 11/09/2022] Open
Abstract
Repeated stressful events are associated with the onset of major depressive disorder (MDD). We previously showed oligodendrocyte (OL)-specific activation of the serum/glucocorticoid-regulated kinase (SGK)1 cascade, increased expression of axon-myelin adhesion molecules, and elaboration of the oligodendrocytic arbor in the corpus callosum of chronically stressed mice. In the current study, we demonstrate that the nodes and paranodes of Ranvier in the corpus callosum were narrower in these mice. Chronic stress also led to diffuse redistribution of Caspr and Kv 1.1 and decreased the activity in white matter, suggesting a link between morphological changes in OLs and inhibition of axonal activity. OL primary cultures subjected to chronic stress resulted in SGK1 activation and translocation to the nucleus, where it inhibited the transcription of metabotropic glutamate receptors (mGluRs). Furthermore, the cAMP level and membrane potential of OLs were reduced by chronic stress exposure. We showed by diffusion tensor imaging that the corpus callosum of patients with MDD exhibited reduced fractional anisotropy, reflecting compromised white matter integrity possibly caused by axonal damage. Our findings suggest that chronic stress disrupts the organization of the nodes of Ranvier by suppressing mGluR activation in OLs, and that specific white matter abnormalities are closely associated with MDD onset.
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Affiliation(s)
- Shingo Miyata
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Manabu Taniguchi
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yoshihisa Koyama
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shoko Shimizu
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Takashi Tanaka
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Fumihiko Yasuno
- Department of Psychiatry, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Akihide Yamamoto
- Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka 565-8565, Japan
| | - Hidehiro Iida
- Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka 565-8565, Japan
| | - Takashi Kudo
- Department of Psychiatry, Osaka University Health Care Center, Toyonaka, Osaka 560-0043, Japan.,Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Osaka 565-0871, Japan
| | - Masaya Tohyama
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan.,Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Osaka 565-0871, Japan.,Osaka Prefectural Hospital Organization, Osaka 558-8558, Japan
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24
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Micu I, Plemel JR, Lachance C, Proft J, Jansen AJ, Cummins K, van Minnen J, Stys PK. The molecular physiology of the axo-myelinic synapse. Exp Neurol 2016; 276:41-50. [DOI: 10.1016/j.expneurol.2015.10.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 01/18/2023]
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25
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Abstract
Neuroglia, the "glue" that fills the space between neurons in the central nervous system, takes active part in nerve cell signaling. Neuroglial cells, astroglia, oligodendroglia, and microglia, are together about as numerous as neurons in the brain as a whole, and in the cerebral cortex grey matter, but the proportion varies widely among brain regions. Glial volume, however, is less than one-fifth of the tissue volume in grey matter. When stimulated by neurons or other cells, neuroglial cells release gliotransmitters by exocytosis, similar to neurotransmitter release from nerve endings, or by carrier-mediated transport or channel flux through the plasma membrane. Gliotransmitters include the common neurotransmitters glutamate and GABA, the nonstandard amino acid d-serine, the high-energy phosphate ATP, and l-lactate. The latter molecule is a "buffer" between glycolytic and oxidative metabolism as well as a signaling substance recently shown to act on specific lactate receptors in the brain. Complementing neurotransmission at a synapse, neuroglial transmission often implies diffusion of the transmitter over a longer distance and concurs with the concept of volume transmission. Transmission from glia modulates synaptic neurotransmission based on energetic and other local conditions in a volume of tissue surrounding the individual synapse. Neuroglial transmission appears to contribute significantly to brain functions such as memory, as well as to prevalent neuropathologies.
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Affiliation(s)
- Vidar Gundersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Jon Storm-Mathisen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Linda Hildegard Bergersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
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26
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Abstract
PURPOSE OF REVIEW The axon plays a central role in both the injury and repair phases after stroke. This review highlights emerging principles in the study of axonal injury in stroke and the role of the axon in neural repair after stroke. RECENT FINDINGS Ischemic stroke produces a rapid and significant loss of axons in the acute phase. This early loss of axons results from a primary ischemic injury that triggers a wave of calcium signaling, activating proteolytic mechanisms and downstream signaling cascades. A second progressive phase of axonal injury occurs during the subacute period and damages axons that survive the initial ischemic insult but go on to experience a delayed axonal degeneration driven in part by changes in axoglial contact and axonal energy metabolism. Recovery from stroke is dependent on axonal sprouting and reconnection that occurs during a third degenerative/regenerative phase. Despite this central role played by the axon, comparatively little is understood about the molecular pathways that contribute to early and subacute axonal degeneration after stroke. Recent advances in axonal neurobiology and signaling suggest new targets that hold promise as potential molecular therapeutics including axonal calcium signaling, axoglial energy metabolism and cell adhesion as well as retrograde axonal mitogen-activated protein kinase pathways. These novel pathways must be modeled appropriately as the type and severity of axonal injury vary by stroke subtype. SUMMARY Stroke-induced injury to axons occurs in three distinct phases each with a unique molecular underpinning. A wealth of new data about the molecular organization and molecular signaling within axons is available but not yet robustly applied to the study of axonal injury after stroke. Identifying the spatiotemporal patterning of molecular pathways within the axon that contribute to injury and repair may offer new therapeutic strategies for the treatment of stroke.
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27
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Ju WK, Kim KY, Noh YH, Hoshijima M, Lukas TJ, Ellisman MH, Weinreb RN, Perkins GA. Increased mitochondrial fission and volume density by blocking glutamate excitotoxicity protect glaucomatous optic nerve head astrocytes. Glia 2015; 63:736-53. [PMID: 25557093 PMCID: PMC4373968 DOI: 10.1002/glia.22781] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 12/03/2014] [Indexed: 12/31/2022]
Abstract
Abnormal structure and function of astrocytes have been observed within the lamina cribrosa region of the optic nerve head (ONH) in glaucomatous neurodegeneration. Glutamate excitotoxicity-mediated mitochondrial alteration has been implicated in experimental glaucoma. However, the relationships among glutamate excitotoxicity, mitochondrial alteration and ONH astrocytes in the pathogenesis of glaucoma remain unknown. We found that functional N-methyl-d-aspartate (NMDA) receptors (NRs) are present in human ONH astrocytes and that glaucomatous human ONH astrocytes have increased expression levels of NRs and the glutamate aspartate transporter. Glaucomatous human ONH astrocytes exhibit mitochondrial fission that is linked to increased expression of dynamin-related protein 1 and its phosphorylation at Serine 616. In BAC ALDH1L1 eGFP or Thy1-CFP transgenic mice, NMDA treatment induced axon loss as well as hypertrophic morphology and mitochondrial fission in astrocytes of the glial lamina. In human ONH astrocytes, NMDA treatment in vitro triggered mitochondrial fission by decreasing mitochondrial length and number, thereby reducing mitochondrial volume density. However, blocking excitotoxicity by memantine (MEM) prevented these alterations by increasing mitochondrial length, number and volume density. In glaucomatous DBA/2J (D2) mice, blocking excitotoxicity by MEM inhibited the morphological alteration as well as increased mitochondrial number and volume density in astrocytes of the glial lamina. However, blocking excitotoxicity decreased autophagosome/autolysosome volume density in both astrocytes and axons in the glial lamina of glaucomatous D2 mice. These findings provide evidence that blocking excitotoxicity prevents ONH astrocyte dysfunction in glaucomatous neurodegeneration by increasing mitochondrial fission, increasing mitochondrial volume density and length, and decreasing autophagosome/autolysosome formation. GLIA 2015;63:736-753.
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Affiliation(s)
- Won-Kyu Ju
- Department of Ophthalmology, Laboratory for Optic Nerve Biology, Hamilton Glaucoma Center, University of California San DiegoLa Jolla, California
| | - Keun-Young Kim
- Center for Research on Biological Systems, National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San DiegoLa Jolla, California
| | - You Hyun Noh
- Department of Ophthalmology, Laboratory for Optic Nerve Biology, Hamilton Glaucoma Center, University of California San DiegoLa Jolla, California
| | - Masahiko Hoshijima
- Center for Research on Biological Systems, National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San DiegoLa Jolla, California
- Department of Medicine, University of California San DiegoLa Jolla, California
| | - Thomas J Lukas
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern UniversityChicago, Illinois
| | - Mark H Ellisman
- Center for Research on Biological Systems, National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San DiegoLa Jolla, California
| | - Robert N Weinreb
- Department of Ophthalmology, Laboratory for Optic Nerve Biology, Hamilton Glaucoma Center, University of California San DiegoLa Jolla, California
| | - Guy A Perkins
- Center for Research on Biological Systems, National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San DiegoLa Jolla, California
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Panthee N, Ono M, Morota T, Tanaka T, Itoda Y, Ikemura M, Yamamoto T, Suzuki H, Saito A, Motomura N. Paraplegia prevention by oral pretreatment with memantine in a rabbit model. J Thorac Cardiovasc Surg 2014; 148:1732-8. [PMID: 24908351 DOI: 10.1016/j.jtcvs.2014.04.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 04/22/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To evaluate the role of memantine (N-methyl-d-aspartate receptor antagonist) pretreatment for the prevention of spinal cord ischemia after infrarenal aortic clamping in a rabbit model. METHODS Thirty New Zealand White rabbits were divided into 5 different groups of 6 rabbits. Groups 60-7 and 60-5 received oral memantine 60 mg once a day for 7 and 5 days, respectively, and groups 30-5 and 30-3 received oral memantine 30 mg once a day for 5 and 3 days, respectively, all before surgery. Group C (control) received normal feeds without memantine. A paraplegic model was created by clamping both the aorta and the inferior vena cava infrarenally and just proximal to their bifurcations for 45 minutes. The modified Tarlov score, motor evoked potential (MEP), serum memantine concentration, and histopathology of the spinal cord were evaluated. RESULTS The mean modified Tarlov scores were 4.2±1.3, 4.3±1.0, 4.2±1.3, 4.3±1.2, and 0.8±1.6 in groups 60-7, 60-5, 30-5, 30-3, and C, respectively at 6, 24, 48, and 72 hours (P<.009 for individual groups vs control). Percentage amplitude loss of MEP by the end of surgery was 29.5%±46.3%, 11.9%±28.0%, 30.0%±46.8%, 16.7%±40.8%, and 81.8%±40.3% for the 5 groups, respectively (P=.049). After declamping, MEP reappeared in 83%, 100%, 83%, 83%, and 33% of cases in the 5 groups, respectively (P=.073). The serum memantine level was similar in the 4 memantine groups. Spinal cords were normal in most of the rabbits in groups 60-7, 60-5, 30-5, and 30-3, but severely ischemic in most of the rabbits in group C (P=.041). CONCLUSIONS Oral memantine pretreatment is protective against spinal cord ischemia, and can be an additional strategy for the prevention of paraplegia during thoracoabdominal aortic surgeries.
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Affiliation(s)
- Nirmal Panthee
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Minoru Ono
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
| | - Tetsuro Morota
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Tsuruhito Tanaka
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Yoshifumi Itoda
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Masako Ikemura
- Department of Neuropathology, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Takehito Yamamoto
- Department of Pharmacy, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Aya Saito
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
| | - Noboru Motomura
- Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan
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Yamazaki Y, Fujiwara H, Kaneko K, Hozumi Y, Xu M, Ikenaka K, Fujii S, Tanaka KF. Short- and long-term functional plasticity of white matter induced by oligodendrocyte depolarization in the hippocampus. Glia 2014; 62:1299-312. [PMID: 24756966 DOI: 10.1002/glia.22681] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/07/2014] [Accepted: 04/10/2014] [Indexed: 11/06/2022]
Abstract
Plastic changes in white matter have received considerable attention in relation to normal cognitive function and learning. Oligodendrocytes and myelin, which constitute the white matter in the central nervous system, can respond to neuronal activity with prolonged depolarization of membrane potential and/or an increase in the intracellular Ca(2+) concentration. Depolarization of oligodendrocytes increases the conduction velocity of an action potential along axons myelinated by the depolarized oligodendrocytes, indicating that white matter shows functional plasticity, as well as structural plasticity. However, the properties and mechanism of oligodendrocyte depolarization-induced functional plastic changes in white matter are largely unknown. Here, we investigated the functional plasticity of white matter in the hippocampus using mice with oligodendrocytes expressing channelrhodopsin-2. Using extracellular recordings of compound action potentials at the alveus of the hippocampus, we demonstrated that light-evoked depolarization of oligodendrocytes induced early- and late-onset facilitation of axonal conduction that was dependent on the magnitude of oligodendrocyte depolarization; the former lasted for approximately 10 min, whereas the latter continued for up to 3 h. Using whole-cell recordings from CA1 pyramidal cells and recordings of antidromic action potentials, we found that the early-onset short-lasting component included the synchronization of action potentials. Moreover, pharmacological analysis demonstrated that the activation of Ba(2+) -sensitive K(+) channels was involved in early- and late-onset facilitation, whereas 4-aminopyridine-sensitive K(+) channels were only involved in the early-onset component. These results demonstrate that oligodendrocyte depolarization induces short- and long-term functional plastic changes in the white matter of the hippocampus and plays active roles in brain functions.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan
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Dzamba D, Honsa P, Anderova M. NMDA Receptors in Glial Cells: Pending Questions. Curr Neuropharmacol 2013; 11:250-62. [PMID: 24179462 PMCID: PMC3648778 DOI: 10.2174/1570159x11311030002] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/08/2013] [Accepted: 02/02/2013] [Indexed: 01/28/2023] Open
Abstract
Glutamate receptors of the N-methyl-D-aspartate (NMDA) type are involved in many cognitive processes, including behavior, learning and synaptic plasticity. For a long time NMDA receptors were thought to be the privileged domain of neurons; however, discoveries of the last 25 years have demonstrated their active role in glial cells as well. Despite the large number of studies in the field, there are many unresolved questions connected with NMDA receptors in glia that are still a matter of debate. The main objective of this review is to shed light on these controversies by summarizing results from all relevant works concerning astrocytes, oligodendrocytes and polydendrocytes (also known as NG2 glial cells) in experimental animals, further extended by studies performed on human glia. The results are divided according to the study approach to enable a better comparison of how findings obtained at the mRNA level correspond with protein expression or functionality. Furthermore, special attention is focused on the NMDA receptor subunits present in the particular glial cell types, which give them special characteristics different from those of neurons – for example, the absence of Mg2+ block and decreased Ca2+ permeability. Since glial cells are implicated in important physiological and pathophysiological roles in the central nervous system (CNS), the last part of this review provides an overview of glial NMDA receptors with respect to ischemic brain injury.
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Affiliation(s)
- David Dzamba
- Department of Cellular Neurophysiology, Institute of Experimental Medicine AS CR, Prague, Czech Republic and Second Medical Faculty, Charles University, Prague, Czech Republic
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31
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Kato TA, Watabe M, Kanba S. Neuron-glia interaction as a possible glue to translate the mind-brain gap: a novel multi-dimensional approach toward psychology and psychiatry. Front Psychiatry 2013; 4:139. [PMID: 24155727 PMCID: PMC3804762 DOI: 10.3389/fpsyt.2013.00139] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/07/2013] [Indexed: 12/28/2022] Open
Abstract
Neurons and synapses have long been the dominant focus of neuroscience, thus the pathophysiology of psychiatric disorders has come to be understood within the neuronal doctrine. However, the majority of cells in the brain are not neurons but glial cells including astrocytes, oligodendrocytes, and microglia. Traditionally, neuroscientists regarded glial functions as simply providing physical support and maintenance for neurons. Thus, in this limited role glia had been long ignored. Recently, glial functions have been gradually investigated, and increasing evidence has suggested that glial cells perform important roles in various brain functions. Digging up the glial functions and further understanding of these crucial cells, and the interaction between neurons and glia may shed new light on clarifying many unknown aspects including the mind-brain gap, and conscious-unconscious relationships. We briefly review the current situation of glial research in the field, and propose a novel translational research with a multi-dimensional model, combining various experimental approaches such as animal studies, in vitro & in vivo neuron-glia studies, a variety of human brain imaging investigations, and psychometric assessments.
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Affiliation(s)
- Takahiro A Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University , Fukuoka , Japan ; Innovation Center for Medical Redox Navigation, Kyushu University , Fukuoka , Japan
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Tsutsui S, Stys PK. Metabolic injury to axons and myelin. Exp Neurol 2013; 246:26-34. [DOI: 10.1016/j.expneurol.2012.04.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 03/20/2012] [Accepted: 04/23/2012] [Indexed: 12/31/2022]
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Makinodan M, Okuda-Yamamoto A, Ikawa D, Toritsuka M, Takeda T, Kimoto S, Tatsumi K, Okuda H, Nakamura Y, Wanaka A, Kishimoto T. Oligodendrocyte plasticity with an intact cell body in vitro. PLoS One 2013; 8:e66124. [PMID: 23762472 PMCID: PMC3676349 DOI: 10.1371/journal.pone.0066124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 05/01/2013] [Indexed: 11/21/2022] Open
Abstract
Demyelination is generally regarded as a consequence of oligodendrocytic cell death. Oligodendrocyte processes that form myelin sheaths may, however, degenerate and regenerate independently of the cell body, in which case cell death does not necessarily occur. We provide here the first evidence of retraction and regeneration of oligodendrocyte processes with no cell death in vitro, using time-lapse imaging. When processes were severed mechanically in vitro, the cells did not undergo cell death and the processes regenerated in 36 h. In a separate experiment, moderate N-methyl-D-aspartate (NMDA) stimuli caused process retraction without apparent cell death, and the processes regained their elaborate morphology after NMDA was removed from the culture medium. These results strongly suggest that demyelination and remyelination can take place without concomitant cell death, at least in vitro. Process regeneration may therefore become a target for future therapy of demyelinating disorders.
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Harauz G, Boggs JM. Myelin management by the 18.5-kDa and 21.5-kDa classic myelin basic protein isoforms. J Neurochem 2013; 125:334-61. [PMID: 23398367 DOI: 10.1111/jnc.12195] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/15/2022]
Abstract
The classic myelin basic protein (MBP) splice isoforms range in nominal molecular mass from 14 to 21.5 kDa, and arise from the gene in the oligodendrocyte lineage (Golli) in maturing oligodendrocytes. The 18.5-kDa isoform that predominates in adult myelin adheres the cytosolic surfaces of oligodendrocyte membranes together, and forms a two-dimensional molecular sieve restricting protein diffusion into compact myelin. However, this protein has additional roles including cytoskeletal assembly and membrane extension, binding to SH3-domains, participation in Fyn-mediated signaling pathways, sequestration of phosphoinositides, and maintenance of calcium homeostasis. Of the diverse post-translational modifications of this isoform, phosphorylation is the most dynamic, and modulates 18.5-kDa MBP's protein-membrane and protein-protein interactions, indicative of a rich repertoire of functions. In developing and mature myelin, phosphorylation can result in microdomain or even nuclear targeting of the protein, supporting the conclusion that 18.5-kDa MBP has significant roles beyond membrane adhesion. The full-length, early-developmental 21.5-kDa splice isoform is predominantly karyophilic due to a non-traditional P-Y nuclear localization signal, with effects such as promotion of oligodendrocyte proliferation. We discuss in vitro and recent in vivo evidence for multifunctionality of these classic basic proteins of myelin, and argue for a systematic evaluation of the temporal and spatial distributions of these protein isoforms, and their modified variants, during oligodendrocyte differentiation.
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Affiliation(s)
- George Harauz
- Department of Molecular and Cellular Biology, Biophysics Interdepartmental Group and Collaborative Program in Neuroscience, University of Guelph, Guelph, Ontario, Canada.
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Egawa T, Hirabayashi K, Koide Y, Kobayashi C, Takahashi N, Mineno T, Terai T, Ueno T, Komatsu T, Ikegaya Y, Matsuki N, Nagano T, Hanaoka K. Red Fluorescent Probe for Monitoring the Dynamics of Cytoplasmic Calcium Ions. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201210279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Egawa T, Hirabayashi K, Koide Y, Kobayashi C, Takahashi N, Mineno T, Terai T, Ueno T, Komatsu T, Ikegaya Y, Matsuki N, Nagano T, Hanaoka K. Red Fluorescent Probe for Monitoring the Dynamics of Cytoplasmic Calcium Ions. Angew Chem Int Ed Engl 2013; 52:3874-7. [DOI: 10.1002/anie.201210279] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 01/26/2013] [Indexed: 01/20/2023]
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37
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Egawa T, Hanaoka K, Koide Y, Ujita S, Takahashi N, Ikegaya Y, Matsuki N, Terai T, Ueno T, Komatsu T, Nagano T. Development of a Far-Red to Near-Infrared Fluorescence Probe for Calcium Ion and its Application to Multicolor Neuronal Imaging. J Am Chem Soc 2011; 133:14157-9. [DOI: 10.1021/ja205809h] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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38
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Stys PK. The axo-myelinic synapse. Trends Neurosci 2011; 34:393-400. [PMID: 21741098 DOI: 10.1016/j.tins.2011.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/01/2011] [Accepted: 06/04/2011] [Indexed: 01/19/2023]
Abstract
Axons have evolved to acquire myelination, enabling denser packing and speedier transmission. Although myelin is considered a passive insulator, recent reports suggest a more dynamic role. Axons, in turn, are endowed with neurotransmitter release and uptake systems along their trunks. Based on these observations, I argue that there may exist a new type of chemical synapse between axon and myelin, one that supports activity-dependent communication between the two. This raises intriguing possibilities of dynamic fine-tuning of the myelin sheath even in adulthood, efficient recruitment of resources for myelin maintenance and bi-directional signaling, whereby the axon informs its myelinating cell of its metabolic needs proportionally to the electrical traffic it is transmitting. This would also have implications for de- and dysmyelinating diseases should this axo-myelinic synapse become dysfunctional.
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Affiliation(s)
- Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
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39
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Huff TB, Shi Y, Sun W, Wu W, Shi R, Cheng JX. Real-time CARS imaging reveals a calpain-dependent pathway for paranodal myelin retraction during high-frequency stimulation. PLoS One 2011; 6:e17176. [PMID: 21390223 PMCID: PMC3048389 DOI: 10.1371/journal.pone.0017176] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 01/24/2011] [Indexed: 11/21/2022] Open
Abstract
High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS) imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down.
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Affiliation(s)
- Terry B. Huff
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Yunzhou Shi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Wenjing Sun
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Wei Wu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Riyi Shi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Ji-Xin Cheng
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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40
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Belfield KD, Bondar MV, Frazer A, Morales AR, Kachkovsky OD, Mikhailov IA, Masunov AE, Przhonska OV. Fluorene-based metal-ion sensing probe with high sensitivity to Zn2+ and efficient two-photon absorption. J Phys Chem B 2010; 114:9313-21. [PMID: 20590077 DOI: 10.1021/jp104450m] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysical, photochemical, two-photon absorption (2PA) and metal ion sensing properties of a new fluorene derivative (E)-1-(7-(4-(benzo[d]thiazol-2-yl)styryl)-9,9-bis(2-(2-ethoxyethoxy)ethyl)-9H-fluoren-2-yl)-3-(2-(9,10,16,17,18,19,21,22,23,24-decahydro-6H dibenzo[h,s][1,4,7,11,14,17]trioxatriazacycloicosin-20(7H)-yl)ethyl)thiourea (1) were investigated in organic and aqueous media. High sensitivity and selectivity of 1 to Zn(2+) in tetrahydrofuran and a water/acetonitrile mixture were shown by both absorption and fluorescence titration. The observed complexation processes corresponded to 1:1 stoichiometry with the range of binding constants approximately (2-3) x 10(5) M(-1). The degenerate 2PA spectra of 1 and 1/Zn(2+) complex were obtained in the 640-900 nm spectral range with the maximum values of two-photon action cross section for ligand/metal complex approximately (90-130) GM, using a standard two-photon induced fluorescence methodology under femtosecond excitation. The nature of the 2PA bands was analyzed by quantum chemical methods and a specific dependence on metal ion binding processes was shown. Ratiometric fluorescence detection (420/650 nm) provided a good dynamic range (10(-4) to 10(-6) M) for detecting Zn(2+), which along with the good photostability and 2PA properties of probe 1 makes it a good candidate in two-photon fluorescence microscopy imaging and sensing of Zn ions.
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Affiliation(s)
- Kevin D Belfield
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, USA
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Abstract
NMDA receptors are typically excited by a combination of glutamate and glycine. Here we describe excitatory responses in CNS myelin that are gated by a glycine agonist alone and mediated by NR1/NR3 "NMDA" receptor subunits. Response properties include activation by d-serine, inhibition by the glycine-site antagonist CNQX, and insensitivity to the glutamate-site antagonist d-APV. d-Serine responses were abrogated in NR3A-deficient mice. Our results suggest the presence of functional NR1/NR3 receptors in CNS myelin.
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Wan Y, Yan L, Zhao Z, Ma X, Guo Q, Jia M, Lu P, Ramos-Ortiz G, Maldonado JL, Rodríguez M, Xia A. Gigantic Two-Photon Absorption Cross Sections and Strong Two-Photon Excited Fluorescence in Pyrene Core Dendrimers with Fluorene/Carbazole as Dendrons and Acetylene as Linkages. J Phys Chem B 2010; 114:11737-45. [DOI: 10.1021/jp104868j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yan Wan
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Linyin Yan
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Zujin Zhao
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Xiaonan Ma
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Qianjin Guo
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Mingli Jia
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Ping Lu
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Gabriel Ramos-Ortiz
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - José Luis Maldonado
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Mario Rodríguez
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
| | - Andong Xia
- The State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China, and Centro de Investigaciones en Óptica A.P. 1-948, CP 37000 León, Guanajuato, México
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Chao D, Xia Y. Ionic storm in hypoxic/ischemic stress: can opioid receptors subside it? Prog Neurobiol 2009; 90:439-70. [PMID: 20036308 DOI: 10.1016/j.pneurobio.2009.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 12/17/2022]
Abstract
Neurons in the mammalian central nervous system are extremely vulnerable to oxygen deprivation and blood supply insufficiency. Indeed, hypoxic/ischemic stress triggers multiple pathophysiological changes in the brain, forming the basis of hypoxic/ischemic encephalopathy. One of the initial and crucial events induced by hypoxia/ischemia is the disruption of ionic homeostasis characterized by enhanced K(+) efflux and Na(+)-, Ca(2+)- and Cl(-)-influx, which causes neuronal injury or even death. Recent data from our laboratory and those of others have shown that activation of opioid receptors, particularly delta-opioid receptors (DOR), is neuroprotective against hypoxic/ischemic insult. This protective mechanism may be one of the key factors that determine neuronal survival under hypoxic/ischemic condition. An important aspect of the DOR-mediated neuroprotection is its action against hypoxic/ischemic disruption of ionic homeostasis. Specially, DOR signal inhibits Na(+) influx through the membrane and reduces the increase in intracellular Ca(2+), thus decreasing the excessive leakage of intracellular K(+). Such protection is dependent on a PKC-dependent and PKA-independent signaling pathway. Furthermore, our novel exploration shows that DOR attenuates hypoxic/ischemic disruption of ionic homeostasis through the inhibitory regulation of Na(+) channels. In this review, we will first update current information regarding the process and features of hypoxic/ischemic disruption of ionic homeostasis and then discuss the opioid-mediated regulation of ionic homeostasis, especially in hypoxic/ischemic condition, and the underlying mechanisms.
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Affiliation(s)
- Dongman Chao
- Yale University School of Medicine, Department of Pediatrics, New Haven, CT 06520, USA
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Bélanger E, Bégin S, Laffray S, De Koninck Y, Vallée R, Côté D. Quantitative myelin imaging with coherent anti-Stokes Raman scattering microscopy: alleviating the excitation polarization dependence with circularly polarized laser beams. OPTICS EXPRESS 2009; 17:18419-32. [PMID: 20372572 DOI: 10.1364/oe.17.018419] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The use of coherent anti-Stokes Raman scattering microscopy tuned to the lipid vibration for quantitative myelin imaging suffers from the excitation polarization dependence of this third-order nonlinear optical effect. The contrast obtained depends on the orientation of the myelin membrane, which in turn affects the morphometric parameters that can be extracted with image analysis. We show how circularly polarized laser beams can be used to avoid this complication, leading to images free of excitation polarization dependence. The technique promises to be optimal for in vivo imaging and the resulting images can be used for coherent anti-Stokes Raman scattering optical histology on native state tissue.
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Affiliation(s)
- E Bélanger
- Centre de Recherche Université Laval Robert-Giffard, Université Laval, Québec, QC G1J 2G3, Canada
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Fu Y, Huff TB, Wang HW, Wang H, Cheng JX. Ex vivo and in vivo imaging of myelin fibers in mouse brain by coherent anti-Stokes Raman scattering microscopy. OPTICS EXPRESS 2008; 16:19396-409. [PMID: 19030027 PMCID: PMC2690080 DOI: 10.1364/oe.16.019396] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Coherent anti-Stokes Raman scattering (CARS) microscopy was applied to image myelinated fibers in different regions of a mouse brain. The CARS signal from the CH2 symmetric stretching vibration allows label-free imaging of myelin sheath with 3D sub-micron resolution. Compared with two-photon excited fluorescence imaging with lipophilic dye labeling, CARS microscopy provides sharper contrast and avoids photobleaching. The CARS signal exhibits excitation polarization dependence which can be eliminated by reconstruction of two complementary images with perpendicular excitation polarizations. The capability of imaging myelinated fibers without exogenous labeling was used to map the whole brain white matter in brain slices and to analyze the microstructural anatomy of brain axons. Quantitative information about fiber volume%, myelin density, and fiber orientations was derived. Combining CARS with two-photon excited fluorescence allowed multimodal imaging of myelinated axons and other cells. Furthermore, in vivo CARS imaging on an upright microscope clearly identified fiber bundles in brain subcortex white matter. These advances open up new opportunities for the study of brain connectivity and neurological disorders.
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Affiliation(s)
- Yan Fu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - T. Brandon Huff
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Han-Wei Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Haifeng Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
- Corresponding author:
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Paredes RM, Etzler JC, Watts LT, Zheng W, Lechleiter JD. Chemical calcium indicators. Methods 2008; 46:143-51. [PMID: 18929663 DOI: 10.1016/j.ymeth.2008.09.025] [Citation(s) in RCA: 389] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 09/12/2008] [Indexed: 11/24/2022] Open
Abstract
Our understanding of the underlying mechanisms of Ca2+ signaling as well as our appreciation for its ubiquitous role in cellular processes has been rapidly advanced, in large part, due to the development of fluorescent Ca2+ indicators. In this chapter, we discuss some of the most common chemical Ca2+ indicators that are widely used for the investigation of intracellular Ca2+ signaling. Advantages, limitations and relevant procedures will be presented for each dye including their spectral qualities, dissociation constants, chemical forms, loading methods and equipment for optimal imaging. Chemical indicators now available allow for intracellular Ca2+ detection over a very large range (<50 nM to >50 microM). High affinity indicators can be used to quantify Ca2+ levels in the cytosol while lower affinity indicators can be optimized for measuring Ca2+ in subcellular compartments with higher concentrations. Indicators can be classified into either single wavelength or ratiometric dyes. Both classes require specific lasers, filters, and/or detection methods that are dependent upon their spectral properties and both classes have advantages and limitations. Single wavelength indicators are generally very bright and optimal for Ca2+ detection when more than one fluorophore is being imaged. Ratiometric indicators can be calibrated very precisely and they minimize the most common problems associated with chemical Ca2+ indicators including uneven dye loading, leakage, photobleaching, and changes in cell volume. Recent technical advances that permit in vivo Ca2+ measurements will also be discussed.
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Affiliation(s)
- R Madelaine Paredes
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Musse AA, Polverini E, Raijmakers R, Harauz G. Kinetics of human peptidylarginine deiminase 2 (hPAD2) — Reduction of Ca2+ dependence by phospholipids and assessment of proposed inhibition by paclitaxel side chains. Biochem Cell Biol 2008; 86:437-47. [DOI: 10.1139/o08-124] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Multiple sclerosis is a complex human neurodegenerative disease, characterized by the active destruction of the insulating myelin sheath around the axons in the central nervous system. The physical deterioration of myelin is mediated by hyperdeimination of myelin basic and other proteins, catalysed by the Ca2+-dependent enzyme peptidylarginine deiminase 2 (PAD2). Thus, inhibition of PAD2 may be of value in treatment of this disease. Here, we have first characterized the in vitro kinetic properties of the human peptidylarginine deiminase isoform 2 (hPAD2). Phosphatidylserine and phosphatidylcholine reduced its Ca2+ dependence by almost twofold. Second, we have explored the putative inhibitory action of the methyl ester side chain of paclitaxel (TSME), which shares structural features with a synthetic PAD substrate, viz., the benzoyl-l-arginine ethyl ester (BAEE). Using the known crystallographic structure of the homologous enzyme hPAD4 and in silico molecular docking, we have shown that TSME interacted strongly with the catalytic site, albeit with a 100-fold lower affinity than BAEE. Despite paclitaxel having previously been shown to inhibit hPAD2 in vitro, the side chain of paclitaxel alone did not inhibit this enzyme’s activity.
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Affiliation(s)
- Abdiwahab A. Musse
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - Eugenia Polverini
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - Reinout Raijmakers
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - George Harauz
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
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NMDA receptor blockade with memantine attenuates white matter injury in a rat model of periventricular leukomalacia. J Neurosci 2008; 28:6670-8. [PMID: 18579741 DOI: 10.1523/jneurosci.1702-08.2008] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hypoxia-ischemia (H/I) in the premature infant leads to white matter injury termed periventricular leukomalacia (PVL), the leading cause of subsequent neurological deficits. Glutamatergic excitotoxicity in white matter oligodendrocytes (OLs) mediated by cell surface glutamate receptors (GluRs) of the AMPA subtype has been demonstrated as one factor in this injury. Recently, it has been shown that rodent OLs also express functional NMDA GluRs (NMDARs), and overactivation of these receptors can mediate excitotoxic OL injury. Here we show that preterm human developing OLs express NMDARs during the PVL period of susceptibility, presenting a potential therapeutic target. The expression pattern mirrors that seen in the immature rat. Furthermore, the uncompetitive NMDAR antagonist memantine attenuates NMDA-evoked currents in developing OLs in situ in cerebral white matter of immature rats. Using an H/I rat model of white matter injury, we show in vivo that post-H/I treatment with memantine attenuates acute loss of the developing OL cell surface marker O1 and the mature OL marker MBP (myelin basic protein), and also prevents the long-term reduction in cerebral mantle thickness seen at postnatal day 21 in this model. These protective doses of memantine do not affect normal myelination or cortical growth. Together, these data suggest that NMDAR blockade with memantine may provide an effective pharmacological prevention of PVL in the premature infant.
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Hertz L. Bioenergetics of cerebral ischemia: a cellular perspective. Neuropharmacology 2008; 55:289-309. [PMID: 18639906 DOI: 10.1016/j.neuropharm.2008.05.023] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 05/14/2008] [Accepted: 05/14/2008] [Indexed: 12/27/2022]
Abstract
In cerebral ischemia survival of neurons, astrocytes, oligodendrocytes and endothelial cells is threatened during energy deprivation and/or following re-supply of oxygen and glucose. After a brief summary of characteristics of different cells types, emphasizing the dependence of all on oxidative metabolism, the bioenergetics of focal and global ischemia is discussed, distinguishing between events during energy deprivation and subsequent recovery attempt after re-circulation. Gray and white matter ischemia are described separately, and distinctions are made between mature and immature brains. Next comes a description of bioenergetics in individual cell types in culture during oxygen/glucose deprivation or exposure to metabolic inhibitors and following re-establishment of normal aerated conditions. Due to their expression of NMDA and non-NMDA receptors neurons and oligodendrocytes are exquisitely sensitive to excitotoxicity by glutamate, which reaches high extracellular concentrations in ischemic brain for several reasons, including failing astrocytic uptake. Excitotoxicity kills brain cells by energetic exhaustion (due to Na(+) extrusion after channel-mediated entry) combined with mitochondrial Ca(2+)-mediated injury and formation of reactive oxygen species. Many (but not all) astrocytes survive energy deprivation for extended periods, but after return to aerated conditions they are vulnerable to mitochondrial damage by cytoplasmic/mitochondrial Ca(2+) overload and to NAD(+) deficiency. Ca(2+) overload is established by reversal of Na(+)/Ca(2+) exchangers following Na(+) accumulation during Na(+)-K(+)-Cl(-) cotransporter stimulation or pH regulation, compensating for excessive acid production. NAD(+) deficiency inhibits glycolysis and eventually oxidative metabolism, secondary to poly(ADP-ribose)polymerase (PARP) activity following DNA damage. Hyperglycemia can be beneficial for neurons but increases astrocytic death due to enhanced acidosis.
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Affiliation(s)
- Leif Hertz
- College of Basic Medical Sciences, China Medical University, Shenyang, PR China.
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