1
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Gargareta VI, Berghoff SA, Krauter D, Hümmert S, Marshall-Phelps KLH, Möbius W, Nave KA, Fledrich R, Werner HB, Eichel-Vogel MA. Myelinated peripheral axons are more vulnerable to mechanical trauma in a model of enlarged axonal diameters. Glia 2024; 72:1572-1589. [PMID: 38895764 DOI: 10.1002/glia.24568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 06/21/2024]
Abstract
The velocity of axonal impulse propagation is facilitated by myelination and axonal diameters. Both parameters are frequently impaired in peripheral nerve disorders, but it is not known if the diameters of myelinated axons affect the liability to injury or the efficiency of functional recovery. Mice lacking the adaxonal myelin protein chemokine-like factor-like MARVEL-transmembrane domain-containing family member-6 (CMTM6) specifically from Schwann cells (SCs) display appropriate myelination but increased diameters of peripheral axons. Here we subjected Cmtm6-cKo mice as a model of enlarged axonal diameters to a mild sciatic nerve compression injury that causes temporarily reduced axonal diameters but otherwise comparatively moderate pathology of the axon/myelin-unit. Notably, both of these pathological features were worsened in Cmtm6-cKo compared to genotype-control mice early post-injury. The increase of axonal diameters caused by CMTM6-deficiency thus does not override their injury-dependent decrease. Accordingly, we did not detect signs of improved regeneration or functional recovery after nerve compression in Cmtm6-cKo mice; depleting CMTM6 in SCs is thus not a promising strategy toward enhanced recovery after nerve injury. Conversely, the exacerbated axonal damage in Cmtm6-cKo nerves early post-injury coincided with both enhanced immune response including foamy macrophages and SCs and transiently reduced grip strength. Our observations support the concept that larger peripheral axons are particularly susceptible toward mechanical trauma.
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Affiliation(s)
- Vasiliki-Ilya Gargareta
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Doris Krauter
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | | | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Biology and Psychology, University of Göttingen, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
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2
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Armstrong RC, Sullivan GM, Perl DP, Rosarda JD, Radomski KL. White matter damage and degeneration in traumatic brain injury. Trends Neurosci 2024:S0166-2236(24)00128-0. [PMID: 39127568 DOI: 10.1016/j.tins.2024.07.003] [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: 04/18/2024] [Revised: 06/17/2024] [Accepted: 07/19/2024] [Indexed: 08/12/2024]
Abstract
Traumatic brain injury (TBI) is a complex condition that can resolve over time but all too often leads to persistent symptoms, and the risk of poor patient outcomes increases with aging. TBI damages neurons and long axons within white matter tracts that are critical for communication between brain regions; this causes slowed information processing and neuronal circuit dysfunction. This review focuses on white matter injury after TBI and the multifactorial processes that underlie white matter damage, potential for recovery, and progression of degeneration. A multiscale perspective across clinical and preclinical advances is presented to encourage interdisciplinary insights from whole-brain neuroimaging of white matter tracts down to cellular and molecular responses of axons, myelin, and glial cells within white matter tissue.
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Affiliation(s)
- Regina C Armstrong
- Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Military Traumatic Brain Injury Initiative (MTBI(2)), Bethesda, MD, USA.
| | - Genevieve M Sullivan
- Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Military Traumatic Brain Injury Initiative (MTBI(2)), Bethesda, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Daniel P Perl
- Pathology, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Department of Defense - Uniformed Services University Brain Tissue Repository, Bethesda, MD, USA
| | - Jessica D Rosarda
- Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kryslaine L Radomski
- Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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3
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Nocera S, Marchena MA, Fernández-Gómez B, Gómez-Martín P, Sánchez-Jiménez E, Macías-Castellano A, Laó Y, Cordano C, Gómez-Torres Ó, Luján R, de Castro F. Activation of Shh/Smo is sufficient to maintain oligodendrocyte precursor cells in an undifferentiated state and is not necessary for myelin formation and (re)myelination. Glia 2024; 72:1469-1483. [PMID: 38771121 DOI: 10.1002/glia.24540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/22/2024]
Abstract
Myelination is the terminal step in a complex and precisely timed program that orchestrates the proliferation, migration and differentiation of oligodendroglial cells. It is thought that Sonic Hedgehog (Shh) acting on Smoothened (Smo) participates in regulating this process, but that these effects are highly context dependent. Here, we investigate oligodendroglial development and remyelination from three specific transgenic lines: NG2-CreERT2 (control), Smofl/fl/NG2-CreERT2 (loss of function), and SmoM2/NG2-CreERT2 (gain of function), as well as pharmacological manipulation that enhance or inhibit the Smo pathway (Smoothened Agonist (SAG) or cyclopamine treatment, respectively). To explore the effects of Shh/Smo on differentiation and myelination in vivo, we developed a highly quantifiable model by transplanting oligodendrocyte precursor cells (OPCs) in the retina. We find that myelination is greatly enhanced upon cyclopamine treatment and hypothesize that Shh/Smo could promote OPC proliferation to subsequently inhibit differentiation. Consistent with this hypothesis, we find that the genetic activation of Smo significantly increased numbers of OPCs and decreased oligodendrocyte differentiation when we examined the corpus callosum during development and after cuprizone demyelination and remyelination. However, upon loss of function with the conditional ablation of Smo, myelination in the same scenarios are unchanged. Taken together, our present findings suggest that the Shh pathway is sufficient to maintain OPCs in an undifferentiated state, but is not necessary for myelination and remyelination.
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Affiliation(s)
- Sonia Nocera
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | - Miguel A Marchena
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
- Facultad HM de Ciencias de la Salud de la UCJC, Universidad Camilo José Cela, Madrid, Spain
- NeuroLab, Instituto de Investigación Sanitaria HM Hospitales, Madrid, Spain
| | | | - Paula Gómez-Martín
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | | | | | - Yolanda Laó
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | - Christian Cordano
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, California, USA
- Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health. University of Genoa, Italy
- Department of Neuroscience, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Óscar Gómez-Torres
- Facultad de Ciencias Ambientales, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Rafael Luján
- Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
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4
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Dean T, Ghaemmaghami J, Corso J, Gallo V. The cortical NG2-glia response to traumatic brain injury. Glia 2023; 71:1164-1175. [PMID: 36692058 PMCID: PMC10404390 DOI: 10.1002/glia.24342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/21/2022] [Accepted: 01/03/2023] [Indexed: 01/25/2023]
Abstract
Traumatic brain injury (TBI) is a significant worldwide cause of morbidity and mortality. A chronic neurologic disease bearing the moniker of "the silent epidemic," TBI currently has no targeted therapies to ameliorate cellular loss or enhance functional recovery. Compared with those of astrocytes, microglia, and peripheral immune cells, the functions and mechanisms of NG2-glia following TBI are far less understood, despite NG2-glia comprising the largest population of regenerative cells in the mature cortex. Here, we synthesize the results from multiple rodent models of TBI, with a focus on cortical NG2-glia proliferation and lineage potential, and propose future avenues for glia researchers to address this unique cell type in TBI. As the molecular mechanisms that regulate NG2-glia regenerative potential are uncovered, we posit that future therapeutic strategies may exploit cortical NG2-glia to augment local cellular recovery following TBI.
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Affiliation(s)
- Terry Dean
- Center for Neuroscience Research, Children's National Hospital, Washington, District of Columbia, USA
- Division of Critical Care Medicine, Children's National Hospital, Washington, District of Columbia, USA
| | - Javid Ghaemmaghami
- Center for Neuroscience Research, Children's National Hospital, Washington, District of Columbia, USA
| | - John Corso
- Center for Neuroscience Research, Children's National Hospital, Washington, District of Columbia, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Hospital, Washington, District of Columbia, USA
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5
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Prajapati A, Mehan S, Khan Z. The role of Smo-Shh/Gli signaling activation in the prevention of neurological and ageing disorders. Biogerontology 2023:10.1007/s10522-023-10034-1. [PMID: 37097427 DOI: 10.1007/s10522-023-10034-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/05/2023] [Indexed: 04/26/2023]
Abstract
Sonic hedgehog (Shh) signaling is an essential central nervous system (CNS) pathway involved during embryonic development and later life stages. Further, it regulates cell division, cellular differentiation, and neuronal integrity. During CNS development, Smo-Shh signaling is significant in the proliferation of neuronal cells such as oligodendrocytes and glial cells. The initiation of the downstream signalling cascade through the 7-transmembrane protein Smoothened (Smo) promotes neuroprotection and restoration during neurological disorders. The dysregulation of Smo-Shh is linked to the proteolytic cleavage of GLI (glioma-associated homolog) into GLI3 (repressor), which suppresses target gene expression, leading to the disruption of cell growth processes. Smo-Shh aberrant signalling is responsible for several neurological complications contributing to physiological alterations like increased oxidative stress, neuronal excitotoxicity, neuroinflammation, and apoptosis. Moreover, activating Shh receptors in the brain promotes axonal elongation and increases neurotransmitters released from presynaptic terminals, thereby exerting neurogenesis, anti-oxidation, anti-inflammatory, and autophagy responses. Smo-Shh activators have been shown in preclinical and clinical studies to help prevent various neurodegenerative and neuropsychiatric disorders. Redox signalling has been found to play a critical role in regulating the activity of the Smo-Shh pathway and influencing downstream signalling events. In the current study ROS, a signalling molecule, was also essential in modulating the SMO-SHH gli signaling pathway in neurodegeneration. As a result of this investigation, dysregulation of the pathway contributes to the pathogenesis of various neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD).Thus, Smo-Shh signalling activators could be a potential therapeutic intervention to treat neurocomplications of brain disorders.
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Affiliation(s)
- Aradhana Prajapati
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India
| | - Sidharth Mehan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India.
| | - Zuber Khan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India
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6
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Hiskens MI. Targets of neuroprotection and review of pharmacological interventions in traumatic brain injury. J Pharmacol Exp Ther 2022; 382:149-166. [DOI: 10.1124/jpet.121.001023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/06/2022] [Indexed: 11/22/2022] Open
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7
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Radomski KL, Zi X, Lischka FW, Noble MD, Galdzicki Z, Armstrong RC. Acute axon damage and demyelination are mitigated by 4-aminopyridine (4-AP) therapy after experimental traumatic brain injury. Acta Neuropathol Commun 2022; 10:67. [PMID: 35501931 PMCID: PMC9059462 DOI: 10.1186/s40478-022-01366-z] [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: 02/04/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Damage to long axons in white matter tracts is a major pathology in closed head traumatic brain injury (TBI). Acute TBI treatments are needed that protect against axon damage and promote recovery of axon function to prevent long term symptoms and neurodegeneration. Our prior characterization of axon damage and demyelination after TBI led us to examine repurposing of 4-aminopyridine (4-AP), an FDA-approved inhibitor of voltage-gated potassium (Kv) channels. 4-AP is currently indicated to provide symptomatic relief for patients with chronic stage multiple sclerosis, which involves axon damage and demyelination. We tested clinically relevant dosage of 4-AP as an acute treatment for experimental TBI and found multiple benefits in corpus callosum axons. This randomized, controlled pre-clinical study focused on the first week after TBI, when axons are particularly vulnerable. 4-AP treatment initiated one day post-injury dramatically reduced axon damage detected by intra-axonal fluorescence accumulations in Thy1-YFP mice of both sexes. Detailed electron microscopy in C57BL/6 mice showed that 4-AP reduced pathological features of mitochondrial swelling, cytoskeletal disruption, and demyelination at 7 days post-injury. Furthermore, 4-AP improved the molecular organization of axon nodal regions by restoring disrupted paranode domains and reducing Kv1.2 channel dispersion. 4-AP treatment did not resolve deficits in action potential conduction across the corpus callosum, based on ex vivo electrophysiological recordings at 7 days post-TBI. Thus, this first study of 4-AP effects on axon damage in the acute period demonstrates a significant decrease in multiple pathological hallmarks of axon damage after experimental TBI.
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Affiliation(s)
- Kryslaine L. Radomski
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Xiaomei Zi
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Fritz W. Lischka
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Mark D. Noble
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Box 633, Rochester, NY 14642 USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Regina C. Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
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8
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An implantable human stem cell-derived tissue-engineered rostral migratory stream for directed neuronal replacement. Commun Biol 2021; 4:879. [PMID: 34267315 PMCID: PMC8282659 DOI: 10.1038/s42003-021-02392-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 06/15/2021] [Indexed: 11/16/2022] Open
Abstract
The rostral migratory stream (RMS) facilitates neuroblast migration from the subventricular zone to the olfactory bulb throughout adulthood. Brain lesions attract neuroblast migration out of the RMS, but resultant regeneration is insufficient. Increasing neuroblast migration into lesions has improved recovery in rodent studies. We previously developed techniques for fabricating an astrocyte-based Tissue-Engineered RMS (TE-RMS) intended to redirect endogenous neuroblasts into distal brain lesions for sustained neuronal replacement. Here, we demonstrate that astrocyte-like-cells can be derived from adult human gingiva mesenchymal stem cells and used for TE-RMS fabrication. We report that key proteins enriched in the RMS are enriched in TE-RMSs. Furthermore, the human TE-RMS facilitates directed migration of immature neurons in vitro. Finally, human TE-RMSs implanted in athymic rat brains redirect migration of neuroblasts out of the endogenous RMS. By emulating the brain’s most efficient means for directing neuroblast migration, the TE-RMS offers a promising new approach to neuroregenerative medicine. O’Donnell et al. describe their Tissue-Engineered Rostral Migratory Stream (TE-RMS) comprised of human astrocyte-like cells that can be derived from adult gingival stem cells within one week, which reorganizes into bundles of bidirectional, longitudinally-aligned astrocytes to emulate the endogenous RMS. Establishing immature neuronal migration in vitro and in vivo, their study demonstrates surgical feasibility and proof-of-concept evidence for this nascent technology.
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9
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New Tricks for an Old (Hedge)Hog: Sonic Hedgehog Regulation of Astrocyte Function. Cells 2021; 10:cells10061353. [PMID: 34070740 PMCID: PMC8228508 DOI: 10.3390/cells10061353] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 01/12/2023] Open
Abstract
The Sonic hedgehog (Shh) molecular signaling pathway is well established as a key regulator of neurodevelopment. It regulates diverse cellular behaviors, and its functions vary with respect to cell type, region, and developmental stage, reflecting the incredible pleiotropy of this molecular signaling pathway. Although it is best understood for its roles in development, Shh signaling persists into adulthood and is emerging as an important regulator of astrocyte function. Astrocytes play central roles in a broad array of nervous system functions, including synapse formation and function as well as coordination and orchestration of CNS inflammatory responses in pathological states. Neurons are the source of Shh in the adult, suggesting that Shh signaling mediates neuron-astrocyte communication, a novel role for this multifaceted pathway. Multiple roles for Shh signaling in astrocytes are increasingly being identified, including regulation of astrocyte identity, modulation of synaptic organization, and limitation of inflammation. This review discusses these novel roles for Shh signaling in regulating diverse astrocyte functions in the healthy brain and in pathology.
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10
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Bradshaw DV, Kim Y, Fu A, Marion CM, Radomski KL, McCabe JT, Armstrong RC. Repetitive Blast Exposure Produces White Matter Axon Damage without Subsequent Myelin Remodeling: In Vivo Analysis of Brain Injury Using Fluorescent Reporter Mice. Neurotrauma Rep 2021; 2:180-192. [PMID: 34013219 PMCID: PMC8127063 DOI: 10.1089/neur.2020.0058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The potential effects of blast exposure on the brain health of military personnel have raised concerns and led to increased surveillance of blast exposures. Neuroimaging studies have reported white matter abnormalities in brains of service members with a history of blast exposure. However, blast effects on white matter microstructure remain poorly understood. As a novel approach to screen for white matter effects, transgenic mice that express fluorescent reporters to sensitively detect axon damage and myelin remodeling were exposed to simulated repetitive blasts (once/day on 5 consecutive days). Axons were visualized using Thy1-YFP-16 reporter mice that express yellow fluorescent protein (YFP) in a broad spectrum of neurons. Swelling along damaged axons forms varicosities that fill with YFP. The frequency and size of axonal varicosities were significantly increased in the corpus callosum (CC) and cingulum at 3 days after the final blast exposure, versus in sham procedures. CC immunolabeling for reactive astrocyte and microglial markers was also significantly increased. NG2CreER;mTmG mice were given tamoxifen (TMX) on days 2 and 3 after the final blast to induce fluorescent labeling of newly synthesized myelin membranes, indicating plasticity and/or repair. Myelin synthesis was not altered in the CC over the intervening 4 or 8 weeks after repetitive blast exposure. These experiments show the advantages of transgenic reporter mice for analysis of white matter injury that detects subtle, diffuse axon damage and the dynamic nature of myelin sheaths. These results show that repetitive low-level blast exposures produce infrequent but significant axon damage along with neuroinflammation in white matter.
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Affiliation(s)
- Donald V Bradshaw
- Graduate Program in Neuroscience, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Yeonho Kim
- Center for Neuroscience and Regenerative Medicine, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amanda Fu
- Center for Neuroscience and Regenerative Medicine, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Christina M Marion
- Graduate Program in Neuroscience, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA
| | - Kryslaine L Radomski
- Center for Neuroscience and Regenerative Medicine, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph T McCabe
- Graduate Program in Neuroscience, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Center for Neuroscience and Regenerative Medicine, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Regina C Armstrong
- Graduate Program in Neuroscience, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Center for Neuroscience and Regenerative Medicine, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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11
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Fletcher JL, Dill LK, Wood RJ, Wang S, Robertson K, Murray SS, Zamani A, Semple BD. Acute treatment with TrkB agonist LM22A-4 confers neuroprotection and preserves myelin integrity in a mouse model of pediatric traumatic brain injury. Exp Neurol 2021; 339:113652. [PMID: 33609501 DOI: 10.1016/j.expneurol.2021.113652] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 02/03/2021] [Accepted: 02/15/2021] [Indexed: 02/08/2023]
Abstract
Young children have a high risk of sustaining a traumatic brain injury (TBI), which can have debilitating life-long consequences. Importantly, the young brain shows particular vulnerability to injury, likely attributed to ongoing maturation of the myelinating nervous system at the time of insult. Here, we examined the effect of acute treatment with the partial tropomyosin receptor kinase B (TrkB) agonist, LM22A-4, on pathological and neurobehavioral outcomes after pediatric TBI, with the hypothesis that targeting TrkB would minimize tissue damage and support functional recovery. We focused on myelinated tracts-the corpus callosum and external capsules-based on recent evidence that TrkB activation potentiates oligodendrocyte remyelination. Male mice at postnatal day 21 received an experimental TBI or sham surgery. Acutely post-injury, extensive cell death, a robust glial response and disruption of compact myelin were evident in the injured brain. TBI or sham mice then received intranasal saline vehicle or LM22A-4 for 14 days. Behavior testing was performed from 4 weeks post-injury, and brains were collected at 5 weeks for histology. TBI mice showed hyperactivity, reduced anxiety-like behavior, and social memory impairments. LM22A-4 ameliorated the abnormal anxiolytic phenotype but had no effect on social memory deficits. Use of spectral confocal reflectance microscopy detected persistent myelin fragmentation in the external capsule of TBI mice at 5 weeks post-injury, which was accompanied by regionally distinct deficits in oligodendrocyte progenitor cells and post-mitotic oligodendrocytes, as well as chronic reactive gliosis and atrophy of the corpus callosum and injured external capsule. LM22A-4 treatment ameliorated myelin deficits in the perilesional external capsule, as well as tissue volume loss and the extent of reactive gliosis. However, there was no effect of this TrkB agonist on oligodendroglial populations detected at 5 weeks post-injury. Collectively, our results demonstrate that targeting TrkB immediately after TBI during early life confers neuroprotection and preserves myelin integrity, and this was associated with some improved neurobehavioral outcomes as the pediatric injured brain matures.
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Affiliation(s)
- Jessica L Fletcher
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Larissa K Dill
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Rhiannon J Wood
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Sharon Wang
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Kate Robertson
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Simon S Murray
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Akram Zamani
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
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12
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Pringle AK, Solomon E, Coles BJ, Desousa BR, Shtaya A, Gajavelli S, Dabab N, Zaben MJ, Bulters DO, Bullock MR, Ahmed AI. Sonic Hedgehog Signaling Promotes Peri-Lesion Cell Proliferation and Functional Improvement after Cortical Contusion Injury. Neurotrauma Rep 2021; 2:27-38. [PMID: 33748811 PMCID: PMC7962778 DOI: 10.1089/neur.2020.0016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability globally. No drug treatments are available, so interest has turned to endogenous neural stem cells (NSCs) as alternative strategies for treatment. We hypothesized that regulation of cell proliferation through modulation of the sonic hedgehog pathway, a key NSC regulatory pathway, could lead to functional improvement. We assessed sonic hedgehog (Shh) protein levels in the cerebrospinal fluid (CSF) of patients with TBI. Using the cortical contusion injury (CCI) model in rodents, we used pharmacological modulators of Shh signaling to assess cell proliferation within the injured cortex using the marker 5-Ethynyl-2’-deoxyuridine (EdU); 50mg/mL. The phenotype of proliferating cells was determined and quantified. Motor function was assessed using the rotarod test. In patients with TBI there is a reduction of Shh protein in CSF compared with control patients. In rodents, following a severe CCI, quiescent cells become activated. Pharmacologically modulating the Shh signaling pathway leads to changes in the number of newly proliferating injury-induced cells. Upregulation of Shh signaling with Smoothened agonist (SAG) results in an increase of newly proliferating cells expressing glial fibrillary acidic protein (GFAP), whereas the Shh signaling inhibitor cyclopamine leads to a reduction. Some cells expressed doublecortin (DCX) but did not mature into neurons. The SAG-induced increase in proliferation is associated with improved recovery of motor function. Localized restoration of Shh in the injured rodent brain, via increased Shh signaling, has the potential to sustain endogenous cell proliferation and the mitigation of TBI-induced motor deficits albeit without the neuronal differentiation.
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Affiliation(s)
- Ashley K Pringle
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Elshadaie Solomon
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Benjamin J Coles
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Brandon R Desousa
- Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA
| | - Anan Shtaya
- Neurosciences Research Centre, St. George's, University of London, London, United Kingdom
| | - Shyam Gajavelli
- Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA
| | - Nedal Dabab
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Malik J Zaben
- Neuroscience and Mental Health Research Institute, University of Cardiff, Cardiff, Wales, United Kingdom
| | - Diederik O Bulters
- Wessex Neurological Centre, University Hospitals Southampton NHS Trust, Southampton, United Kingdom
| | - M Ross Bullock
- Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA
| | - Aminul I Ahmed
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,Brain Repair and Rehabilitation, Institute of Neurology, London, United Kingdom
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13
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Hill SA, Fu M, Garcia ADR. Sonic hedgehog signaling in astrocytes. Cell Mol Life Sci 2021; 78:1393-1403. [PMID: 33079226 PMCID: PMC7904711 DOI: 10.1007/s00018-020-03668-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/02/2020] [Accepted: 10/05/2020] [Indexed: 01/12/2023]
Abstract
Astrocytes are complex cells that perform a broad array of essential functions in the healthy and injured nervous system. The recognition that these cells are integral components of various processes, including synapse formation, modulation of synaptic activity, and response to injury, underscores the need to identify the molecular signaling programs orchestrating these diverse functional properties. Emerging studies have identified the Sonic hedgehog (Shh) signaling pathway as an essential regulator of the molecular identity and functional properties of astrocytes. Well established as a powerful regulator of diverse neurodevelopmental processes in the embryonic nervous system, its functional significance in astrocytes is only beginning to be revealed. Notably, Shh signaling is active only in discrete subpopulations of astrocytes distributed throughout the brain, a feature that has potential to yield novel insights into functional specialization of astrocytes. Here, we discuss Shh signaling and emerging data that point to essential roles for this pleiotropic signaling pathway in regulating various functional properties of astrocytes in the healthy and injured brain.
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Affiliation(s)
- Steven A Hill
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
| | - Marissa Fu
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
| | - A Denise R Garcia
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA.
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA.
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14
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Neuroprotective Effects of the Sonic Hedgehog Signaling Pathway in Ischemic Injury through Promotion of Synaptic and Neuronal Health. Neural Plast 2020; 2020:8815195. [PMID: 32802036 PMCID: PMC7416279 DOI: 10.1155/2020/8815195] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/05/2020] [Accepted: 06/29/2020] [Indexed: 12/03/2022] Open
Abstract
Cerebral ischemia is a common cerebrovascular condition which often induces neuronal apoptosis, leading to brain damage. The sonic hedgehog (Shh) signaling pathway has been reported to be involved in ischemic stroke, but the underlying mechanisms have not been fully elucidated. In the present study, we demonstrated that expressions of Shh, Ptch, and Gli-1 were significantly downregulated at 24 h following oxygen-glucose deprivation (OGD) injury in neurons in vitro, effects which were associated with increasing numbers of apoptotic cells and reactive oxygen species generation. In addition, expressions of synaptic proteins (neuroligin and neurexin) were significantly downregulated at 8 h following OGD, also associated with concomitant neuronal apoptosis. Treatment with purmorphamine, a Shh agonist, increased Gli-1 in the nucleus of neurons and protected against OGD injury, whereas the Shh inhibitor, cyclopamine, produced the opposite effects. Activation of Shh signals promoted CREB and Akt phosphorylation; upregulated the expressions of BDNF, neuroligin, and neurexin; and decreased NF-κB phosphorylation following OGD. Notably, this activation of Shh signals was accompanied by improved neurobehavioral responses along with attenuations in edema and apoptosis at 48 h postischemic insult in rats. Taken together, these results demonstrate that activation of the Shh signaling pathway played a neuroprotective role in response to ischemic exposure via promotion of synaptic and neuronal health.
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15
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Marin C, Langdon C, Alobid I, Mullol J. Olfactory Dysfunction in Traumatic Brain Injury: the Role of Neurogenesis. Curr Allergy Asthma Rep 2020; 20:55. [PMID: 32648230 DOI: 10.1007/s11882-020-00949-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Olfactory functioning disturbances are common following traumatic brain injury (TBI) having a significant impact on quality of life. A spontaneous recovery of the olfactory function over time may occur in TBI patients. Although there is no standard treatment for patients with posttraumatic olfactory loss, olfactory training (OT) has shown some promise beneficial effects. However, the mechanisms underlying spontaneous recovery and olfactory improvement induced by OT are not completely known. RECENT FINDINGS The spontaneous recovery of the olfactory function and the improvement of olfactory function after OT have recently been associated with an increase in subventricular (SVZ) neurogenesis and an increase in olfactory bulb (OB) glomerular dopaminergic (DAergic) interneurons. In addition, after OT, an increase in electrophysiological responses at the olfactory epithelium (OE) level has been reported, indicating that recovery of olfactory function not only affects olfactory processing at the central level, but also at peripheral level. However, the role of OE stem cells in the spontaneous recovery and in the improvement of olfactory function after OT in TBI is still unknown. In this review, we describe the physiology of the olfactory system, and the olfactory dysfunction after TBI. We highlight the possible role for the SVZ neurogenesis and DAergic OB interneurons in the recovery of the olfactory function. In addition, we point out the relevance of the OE neurogenesis process as a future target for the research in the pathophysiological mechanisms involved in the olfactory dysfunction in TBI. The potential of basal stem cells as a promising candidate for replacement therapies is also described.
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Affiliation(s)
- Concepció Marin
- INGENIO, IRCE, Department 2B, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036, Barcelona, Catalonia, Spain. .,Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Barcelona, Spain.
| | - Cristóbal Langdon
- INGENIO, IRCE, Department 2B, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036, Barcelona, Catalonia, Spain.,Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Barcelona, Spain.,Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Isam Alobid
- INGENIO, IRCE, Department 2B, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036, Barcelona, Catalonia, Spain.,Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Barcelona, Spain.,Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Joaquim Mullol
- INGENIO, IRCE, Department 2B, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036, Barcelona, Catalonia, Spain. .,Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Barcelona, Spain. .,Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Universitat de Barcelona, Barcelona, Catalonia, Spain.
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16
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Purvis EM, O'Donnell JC, Chen HI, Cullen DK. Tissue Engineering and Biomaterial Strategies to Elicit Endogenous Neuronal Replacement in the Brain. Front Neurol 2020; 11:344. [PMID: 32411087 PMCID: PMC7199479 DOI: 10.3389/fneur.2020.00344] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022] Open
Abstract
Neurogenesis in the postnatal mammalian brain is known to occur in the dentate gyrus of the hippocampus and the subventricular zone. These neurogenic niches serve as endogenous sources of neural precursor cells that could potentially replace neurons that have been lost or damaged throughout the brain. As an example, manipulation of the subventricular zone to augment neurogenesis has become a popular strategy for attempting to replace neurons that have been lost due to acute brain injury or neurodegenerative disease. In this review article, we describe current experimental strategies to enhance the regenerative potential of endogenous neural precursor cell sources by enhancing cell proliferation in neurogenic regions and/or redirecting migration, including pharmacological, biomaterial, and tissue engineering strategies. In particular, we discuss a novel replacement strategy based on exogenously biofabricated "living scaffolds" that could enhance and redirect endogenous neuroblast migration from the subventricular zone to specified regions throughout the brain. This approach utilizes the first implantable, biomimetic tissue-engineered rostral migratory stream, thereby leveraging the brain's natural mechanism for sustained neuronal replacement by replicating the structure and function of the native rostral migratory stream. Across all these strategies, we discuss several challenges that need to be overcome to successfully harness endogenous neural precursor cells to promote nervous system repair and functional restoration. With further development, the diverse and innovative tissue engineering and biomaterial strategies explored in this review have the potential to facilitate functional neuronal replacement to mitigate neurological and psychiatric symptoms caused by injury, developmental disorders, or neurodegenerative disease.
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Affiliation(s)
- Erin M. Purvis
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - John C. O'Donnell
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - H. Isaac Chen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - D. Kacy Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
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17
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Losurdo M, Davidsson J, Sköld MK. Diffuse Axonal Injury in the Rat Brain: Axonal Injury and Oligodendrocyte Activity Following Rotational Injury. Brain Sci 2020; 10:E229. [PMID: 32290212 PMCID: PMC7225974 DOI: 10.3390/brainsci10040229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023] Open
Abstract
Traumatic brain injury (TBI) commonly results in primary diffuse axonal injury (DAI) and associated secondary injuries that evolve through a cascade of pathological mechanisms. We aim at assessing how myelin and oligodendrocytes react to head angular-acceleration-induced TBI in a previously described model. This model induces axonal injuries visible by amyloid precursor protein (APP) expression, predominantly in the corpus callosum and its borders. Brain tissue from a total of 27 adult rats was collected at 24 h, 72 h and 7 d post-injury. Coronal sections were prepared for immunohistochemistry and RNAscope® to investigate DAI and myelin changes (APP, MBP, Rip), oligodendrocyte lineage cell loss (Olig2), oligodendrocyte progenitor cells (OPCs) (NG2, PDGFRa) and neuronal stress (HSP70, ATF3). Oligodendrocytes and OPCs numbers (expressed as percentage of positive cells out of total number of cells) were measured in areas with high APP expression. Results showed non-statistically significant trends with a decrease in oligodendrocyte lineage cells and an increase in OPCs. Levels of myelination were mostly unaltered, although Rip expression differed significantly between sham and injured animals in the frontal brain. Neuronal stress markers were induced at the dorsal cortex and habenular nuclei. We conclude that rotational injury induces DAI and neuronal stress in specific areas. We noticed indications of oligodendrocyte death and regeneration without statistically significant changes at the timepoints measured, despite indications of axonal injuries and neuronal stress. This might suggest that oligodendrocytes are robust enough to withstand this kind of trauma, knowledge important for the understanding of thresholds for cell injury and post-traumatic recovery potential.
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Affiliation(s)
- Michela Losurdo
- Department of Neuroscience, Karolinska Institute, 171 77 Stockholm, Sweden;
- Department of Molecular Medicine, Università degli Studi di Pavia, 27100 Pavia, Italy
| | - Johan Davidsson
- Department of Mechanics and Maritime Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden;
| | - Mattias K. Sköld
- Department of Neuroscience, Karolinska Institute, 171 77 Stockholm, Sweden;
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85 Uppsala, Sweden
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18
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Liu D, Bai X, Ma W, Xin D, Chu X, Yuan H, Qiu J, Ke H, Yin S, Chen W, Wang Z. Purmorphamine Attenuates Neuro-Inflammation and Synaptic Impairments After Hypoxic-Ischemic Injury in Neonatal Mice via Shh Signaling. Front Pharmacol 2020; 11:204. [PMID: 32194421 PMCID: PMC7064623 DOI: 10.3389/fphar.2020.00204] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 02/14/2020] [Indexed: 01/05/2023] Open
Abstract
Purmorphamine (PUR), an agonist of the Smoothened (Smo) receptor, has been shown to function as a neuroprotectant in acute experimental ischemic stroke. Its role in hypoxic-ischemic (HI) brain injury in neonatal mice remains unknown. Here we show that PUR attenuated acute brain injury, with a decrease in Bax/Bcl-2 ratio as well as inhibition of caspase-3 activation. These beneficial effects of PUR were associated with suppressing neuro-inflammation and oxidative stress. PUR exerted long-term protective effects upon tissue loss and improved neurobehavioral outcomes as determined at 14 and 28 days post-HI insult. Moreover, PUR increased synaptophysin (Syn) and postsynaptic density (PSD) protein 95 expression in HI-treated mice and attenuated synaptic loss. PUR upregulated the expression of Shh pathway mediators, while suppression of the Shh signaling pathway with cyclopamine (Cyc) reversed these beneficial effects of PUR on HI insult. Our study suggests a therapeutic potential for short-term PUR administration in HI-induced injury as a result of its capacity to exert multiple protective actions upon acute brain injury, long-term memory deficits, and impaired synapses. Moreover, we provide evidence indicating that one of the mechanisms underlying these beneficial effects of PUR involves activation of the Shh signaling pathway.
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Affiliation(s)
- Dexiang Liu
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China
| | - Xuemei Bai
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Weiwei Ma
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China.,Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Danqing Xin
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Xili Chu
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Hongtao Yuan
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Jie Qiu
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China.,Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - HongFei Ke
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Sen Yin
- Qilu Hospital, Shandong University, Jinan, China
| | | | - Zhen Wang
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
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19
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Activation of the Hedgehog Pathway Promotes Recovery of Neurological Function After Traumatic Brain Injury by Protecting the Neurovascular Unit. Transl Stroke Res 2020; 11:720-733. [DOI: 10.1007/s12975-019-00771-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 01/01/2023]
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20
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The Elegance of Sonic Hedgehog: Emerging Novel Functions for a Classic Morphogen. J Neurosci 2019; 38:9338-9345. [PMID: 30381425 DOI: 10.1523/jneurosci.1662-18.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/27/2018] [Accepted: 09/28/2018] [Indexed: 12/12/2022] Open
Abstract
Sonic Hedgehog (SHH) signaling has been most widely known for its role in specifying region and cell-type identity during embryonic morphogenesis. This mini-review accompanies a 2018 SFN mini-symposium that addresses an emerging body of research focused on understanding the diverse roles for Shh signaling in a wide range of contexts in neurodevelopment and, more recently, in the mature CNS. Such research shows that Shh affects the function of brain circuits, including the production and maintenance of diverse cell types and the establishment of wiring specificity. Here, we review these novel and unexpected functions and the unanswered questions regarding the role of SHH and its signaling pathway members in these cases.
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21
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Shahapal A, Cho EB, Yong HJ, Jeong I, Kwak H, Lee JK, Kim W, Kim B, Park HC, Lee WS, Kim H, Hwang JI, Seong JY. FAM19A5 Expression During Embryogenesis and in the Adult Traumatic Brain of FAM19A5-LacZ Knock-in Mice. Front Neurosci 2019; 13:917. [PMID: 31543758 PMCID: PMC6730007 DOI: 10.3389/fnins.2019.00917] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/16/2019] [Indexed: 12/24/2022] Open
Abstract
FAM19A5 is a secretory protein that is predominantly expressed in the brain. Although the FAM19A5 gene has been found to be associated with neurological and/or psychiatric diseases, only limited information is available on its function in the brain. Using FAM19A5-LacZ knock-in mice, we determined the expression pattern of FAM19A5 in developing and adult brains and identified cell types that express FAM19A5 in naïve and traumatic brain injury (TBI)–induced brains. According to X-gal staining results, FAM19A5 is expressed in the ventricular zone and ganglionic eminence at a very early stage of brain development, suggesting its functions are related to the generation of neural stem cells and oligodendrocyte precursor cells (OPCs). In the later stages of developing embryos and in adult mice, FAM19A5 expression expanded broadly to particular regions of the brain, including layers 2/3 and 5 of the cortex, cornu amonis (CA) region of the hippocampus, and the corpus callosum. X-gal staining combined with immunostaining for a variety of cell-type markers revealed that FAM19A5 is expressed in many different cell types, including neurons, OPCs, astrocytes, and microglia; however, only some populations of these cell types produce FAM19A5. In a subpopulation of neuronal cells, TBI led to increased X-gal staining that extended to the nucleus, marked by slightly condensed content and increased heterochromatin formation along the nuclear border. Similarly, nuclear extension of X-gal staining occurred in a subpopulation of OPCs in the corpus callosum of the TBI-induced brain. Together, these results suggest that FAM19A5 plays a role in nervous system development from an early stage and increases its expression in response to pathological conditions in subsets of neurons and OPCs of the adult brain.
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Affiliation(s)
- Anu Shahapal
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Eun Bee Cho
- Neuracle Science Co., Ltd., Seoul, South Korea
| | - Hyo Jeong Yong
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Inyoung Jeong
- Graduate School of Biomedical Sciences, Korea University Ansan Hospital, Ansan, South Korea
| | - Hoyun Kwak
- Neuracle Science Co., Ltd., Seoul, South Korea
| | | | - Wonkyum Kim
- Neuracle Science Co., Ltd., Seoul, South Korea
| | | | - Hae-Chul Park
- Graduate School of Biomedical Sciences, Korea University Ansan Hospital, Ansan, South Korea
| | - Won Suk Lee
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Hyun Kim
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Jong-Ik Hwang
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Jae Young Seong
- Graduate School of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
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22
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Allahyari RV, Clark KL, Shepard KA, Garcia ADR. Sonic hedgehog signaling is negatively regulated in reactive astrocytes after forebrain stab injury. Sci Rep 2019; 9:565. [PMID: 30679745 PMCID: PMC6345977 DOI: 10.1038/s41598-018-37555-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 12/07/2018] [Indexed: 12/19/2022] Open
Abstract
Following injury to the central nervous system, astrocytes perform critical and complex functions that both promote and antagonize neural repair. Understanding the molecular signaling pathways that coordinate their diverse functional properties is key to developing effective therapeutic strategies. In the healthy, adult CNS, Sonic hedgehog (Shh) signaling is active in mature, differentiated astrocytes. Shh has been shown to undergo injury-induced upregulation and promote neural repair. Here, we investigated whether Shh signaling mediates astrocyte response to injury. Surprisingly, we found that following an acute, focal injury, reactive astrocytes exhibit a pronounced reduction in Shh activity in a spatiotemporally-defined manner. Shh signaling is lost in reactive astrocytes at the lesion site, but persists in mild to moderately reactive astrocytes in distal tissues. Nevertheless, local pharmacological activation of the Shh pathway in astrocytes mitigates inflammation, consistent with a neuroprotective role for Shh signaling after injury. Interestingly, we find that Shh signaling is restored to baseline levels two weeks after injury, a time during which acute inflammation has largely subsided and lesions have matured. Taken together, these data suggest that endogenous Shh signaling in astrocytes is dynamically regulated in a context dependent manner. In addition, exogenous activation of the Shh pathway promotes neuroprotection mediated by reactive astrocytes.
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Affiliation(s)
- R Vivian Allahyari
- Departments of Biology and Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19104, USA
| | - K Lyles Clark
- Departments of Biology and Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19104, USA
- Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Katherine A Shepard
- Departments of Biology and Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19104, USA
| | - A Denise R Garcia
- Departments of Biology and Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19104, USA.
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23
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Del Giovane A, Ragnini-Wilson A. Targeting Smoothened as a New Frontier in the Functional Recovery of Central Nervous System Demyelinating Pathologies. Int J Mol Sci 2018; 19:E3677. [PMID: 30463396 PMCID: PMC6274747 DOI: 10.3390/ijms19113677] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/09/2018] [Accepted: 11/14/2018] [Indexed: 12/20/2022] Open
Abstract
Myelin sheaths on vertebrate axons provide protection, vital support and increase the speed of neuronal signals. Myelin degeneration can be caused by viral, autoimmune or genetic diseases. Remyelination is a natural process that restores the myelin sheath and, consequently, neuronal function after a demyelination event, preventing neurodegeneration and thereby neuron functional loss. Pharmacological approaches to remyelination represent a promising new frontier in the therapy of human demyelination pathologies and might provide novel tools to improve adaptive myelination in aged individuals. Recent phenotypical screens have identified agonists of the atypical G protein-coupled receptor Smoothened and inhibitors of the glioma-associated oncogene 1 as being amongst the most potent stimulators of oligodendrocyte precursor cell (OPC) differentiation in vitro and remyelination in the central nervous system (CNS) of mice. Here, we discuss the current state-of-the-art of studies on the role of Sonic Hedgehog reactivation during remyelination, referring readers to other reviews for the role of Hedgehog signaling in cancer and stem cell maintenance.
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Affiliation(s)
- Alice Del Giovane
- Department of Biology University of Rome Tor Vergata, Viale Della Ricerca Scientifica, 00133 Rome, Italy.
| | - Antonella Ragnini-Wilson
- Department of Biology University of Rome Tor Vergata, Viale Della Ricerca Scientifica, 00133 Rome, Italy.
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24
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Experimental Traumatic Brain Injury Identifies Distinct Early and Late Phase Axonal Conduction Deficits of White Matter Pathophysiology, and Reveals Intervening Recovery. J Neurosci 2018; 38:8723-8736. [PMID: 30143572 PMCID: PMC6181309 DOI: 10.1523/jneurosci.0819-18.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/15/2018] [Accepted: 07/10/2018] [Indexed: 01/26/2023] Open
Abstract
Traumatic brain injury (TBI) patients often exhibit slowed information processing speed that can underlie diverse symptoms. Processing speed depends on neural circuit function at synapses, in the soma, and along axons. Long axons in white matter (WM) tracts are particularly vulnerable to TBI. We hypothesized that disrupted axon–myelin interactions that slow or block action potential conduction in WM tracts may contribute to slowed processing speed after TBI. Concussive TBI in male/female mice was used to produce traumatic axonal injury in the corpus callosum (CC), similar to WM pathology in human TBI cases. Compound action potential velocity was slowed along myelinated axons at 3 d after TBI with partial recovery by 2 weeks, suggesting early demyelination followed by remyelination. Ultrastructurally, dispersed demyelinated axons and disorganized myelin attachment to axons at paranodes were apparent within CC regions exhibiting traumatic axonal injury. Action potential conduction is exquisitely sensitive to paranode abnormalities. Molecular identification of paranodes and nodes of Ranvier detected asymmetrical paranode pairs and abnormal heminodes after TBI. Fluorescent labeling of oligodendrocyte progenitors in NG2CreER;mTmG mice showed increased synthesis of new membranes extended along axons to paranodes, indicating remyelination after TBI. At later times after TBI, an overall loss of conducting axons was observed at 6 weeks followed by CC atrophy at 8 weeks. These studies identify a progression of both myelinated axon conduction deficits and axon–myelin pathology in the CC, implicating WM injury in impaired information processing at early and late phases after TBI. Furthermore, the intervening recovery reveals a potential therapeutic window. SIGNIFICANCE STATEMENT Traumatic brain injury (TBI) is a major global health concern. Across the spectrum of TBI severities, impaired information processing can contribute to diverse functional deficits that underlie persistent symptoms. We used experimental TBI to exploit technical advantages in mice while modeling traumatic axonal injury in white matter tracts, which is a key pathological feature of human TBI. A combination of approaches revealed slowed and failed signal conduction along with damage to the structure and molecular composition of myelinated axons in the white matter after TBI. An early regenerative response was not sustained yet reveals a potential time window for intervention. These insights into white matter abnormalities underlying axon conduction deficits can inform strategies to improve treatment options for TBI patients.
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Sanchez MA, Sullivan GM, Armstrong RC. Genetic detection of Sonic hedgehog (Shh) expression and cellular response in the progression of acute through chronic demyelination and remyelination. Neurobiol Dis 2018; 115:145-156. [PMID: 29627579 DOI: 10.1016/j.nbd.2018.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/26/2018] [Accepted: 04/01/2018] [Indexed: 01/20/2023] Open
Abstract
Multiple sclerosis is a demyelinating disease in which neurological deficits result from damage to myelin, axons, and neuron cell bodies. Prolonged or repeated episodes of demyelination impair remyelination. We hypothesized that augmenting Sonic hedgehog (Shh) signaling in chronically demyelinated lesions could enhance oligodendrogenesis and remyelination. Shh regulates oligodendrocyte development during postnatal myelination, and maintains adult neural stem cells. We used genetic approaches to detect Shh expression and Shh responding cells in vivo. ShhCreERT2 or Gli1CreERT2 mice were crossed to reporter mice for genetic fate-labeling of cells actively transcribing Shh or Gli1, an effective readout of canonical Shh signaling. Tamoxifen induction enabled temporal control of recombination at distinct stages of acute and chronic cuprizone demyelination of the corpus callosum. Gli1 fate-labeled cells were rarely found in the corpus callosum with tamoxifen given during acute demyelination stages to examine activated microglia, reactive astrocytes, or remyelinating cells. Gli1 fate-labeled cells, mainly reactive astrocytes, were observed in the corpus callosum with tamoxifen given after chronic demyelination. However, Shh expressing cells were not detected in the corpus callosum during acute or chronic demyelination. Finally, SAG, an agonist of both canonical and type II non-canonical Hedgehog signaling pathways, was microinjected into the corpus callosum after chronic demyelination. Significantly, SAG delivery increased proliferation and enhanced remyelination. SAG did not increase Gli1 fate-labeled cells in the corpus callosum, which may indicate signaling through the non-canonical Hedgehog pathway. These studies demonstrate that Hedgehog pathway interventions may have therapeutic potential to modulate astrogliosis and to promote remyelination after chronic demyelination.
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Affiliation(s)
- Maria A Sanchez
- Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Genevieve M Sullivan
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Regina C Armstrong
- Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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Postnatal Sonic hedgehog (Shh) responsive cells give rise to oligodendrocyte lineage cells during myelination and in adulthood contribute to remyelination. Exp Neurol 2018; 299:122-136. [DOI: 10.1016/j.expneurol.2017.10.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/23/2017] [Accepted: 10/13/2017] [Indexed: 12/21/2022]
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Marin C, Laxe S, Langdon C, Berenguer J, Lehrer E, Mariño-Sánchez F, Alobid I, Bernabeu M, Mullol J. Olfactory function in an excitotoxic model for secondary neuronal degeneration: Role of dopaminergic interneurons. Neuroscience 2017; 364:28-44. [PMID: 28918258 DOI: 10.1016/j.neuroscience.2017.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 09/01/2017] [Accepted: 09/05/2017] [Indexed: 12/26/2022]
Abstract
Secondary neuronal degeneration (SND) occurring in Traumatic brain injury (TBI) consists in downstream destructive events affecting cells that were not or only marginally affected by the initial wound, further increasing the effects of the primary injury. Glutamate excitotoxicity is hypothesized to play an important role in SND. TBI is a common cause of olfactory dysfunction that may be spontaneous and partially recovered. The role of the glutamate excitotoxicity in the TBI-induced olfactory dysfunction is still unknown. We investigated the effects of excitotoxicity induced by bilateral N-Methyl-D-Aspartate (NMDA) OB administration in the olfactory function, OB volumes, and subventricular zone (SVZ) and OB neurogenesis in rats. NMDA OB administration induced a decrease in the number of correct choices in the olfactory discrimination tests one week after lesions (p<0.01), and a spontaneous recovery of the olfactory deficit two weeks after lesions (p<0.05). A lack of correlation between OB volumes and olfactory function was observed. An increase in SVZ neurogenesis (Ki67+ cells, PSANCAM+ cells (p<0.01) associated with an increase in OB glomerular dopaminergic immunostaining (p<0.05) were related to olfactory function recovery. The present results show that changes in OB volumes cannot explain the recovery of the olfactory function and suggest a relevant role for dopaminergic OB interneurons in the pathophysiology of recovery of loss of smell in TBI.
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Affiliation(s)
- Concepció Marin
- INGENIO, IRCE, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.
| | - Sara Laxe
- Brain Injury Unit, Guttmann-Institut-Hospital for Neurorehabilitation adscript UAB, Badalona, Barcelona, Catalonia, Spain
| | - Cristobal Langdon
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clinic, Barcelona, Catalonia, Spain; Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Spain
| | - Joan Berenguer
- Neuroradiology Department, Hospital Clinic, Barcelona, Catalonia, Spain
| | - Eduardo Lehrer
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clinic, Barcelona, Catalonia, Spain
| | - Franklin Mariño-Sánchez
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clinic, Barcelona, Catalonia, Spain; Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Spain
| | - Isam Alobid
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clinic, Barcelona, Catalonia, Spain; Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Spain
| | - Montserrat Bernabeu
- Brain Injury Unit, Guttmann-Institut-Hospital for Neurorehabilitation adscript UAB, Badalona, Barcelona, Catalonia, Spain
| | - Joaquim Mullol
- INGENIO, IRCE, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain; Rhinology Unit and Smell Clinic, ENT Department, Hospital Clinic, Barcelona, Catalonia, Spain; Centre for Biomedical Investigation in Respiratory Diseases (CIBERES), Spain
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Transplanted Adult Neural Stem Cells Express Sonic Hedgehog In Vivo and Suppress White Matter Neuroinflammation after Experimental Traumatic Brain Injury. Stem Cells Int 2017; 2017:9342534. [PMID: 29081811 PMCID: PMC5610817 DOI: 10.1155/2017/9342534] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/19/2017] [Accepted: 06/05/2017] [Indexed: 01/05/2023] Open
Abstract
Neural stem cells (NSCs) delivered intraventricularly may be therapeutic for diffuse white matter pathology after traumatic brain injury (TBI). To test this concept, NSCs isolated from adult mouse subventricular zone (SVZ) were transplanted into the lateral ventricle of adult mice at two weeks post-TBI followed by analysis at four weeks post-TBI. We examined sonic hedgehog (Shh) signaling as a candidate mechanism by which transplanted NSCs may regulate neuroregeneration and/or neuroinflammation responses of endogenous cells. Mouse fluorescent reporter lines were generated to enable in vivo genetic labeling of cells actively transcribing Shh or Gli1 after transplantation and/or TBI. Gli1 transcription is an effective readout for canonical Shh signaling. In ShhCreERT2;R26tdTomato mice, Shh was primarily expressed in neurons and was not upregulated in reactive astrocytes or microglia after TBI. Corroborating results in Gli1CreERT2;R26tdTomato mice demonstrated that Shh signaling was not upregulated in the corpus callosum, even after TBI or NSC transplantation. Transplanted NSCs expressed Shh in vivo but did not increase Gli1 labeling of host SVZ cells. Importantly, NSC transplantation significantly reduced reactive astrogliosis and microglial/macrophage activation in the corpus callosum after TBI. Therefore, intraventricular NSC transplantation after TBI significantly attenuated neuroinflammation, but did not activate host Shh signaling via Gli1 transcription.
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Osier N, Dixon CE. Mini Review of Controlled Cortical Impact: A Well-Suited Device for Concussion Research. Brain Sci 2017; 7:E88. [PMID: 28726717 PMCID: PMC5532601 DOI: 10.3390/brainsci7070088] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/12/2017] [Accepted: 07/18/2017] [Indexed: 01/25/2023] Open
Abstract
Mild traumatic brain injury (mTBI) is increasingly recognized as a significant public health problem which warrants additional research. Part of the effort to understand mTBI and concussion includes modeling in animals. Controlled cortical impact (CCI) is a commonly employed and well-characterized model of experimental TBI that has been utilized for three decades. Today, several commercially available pneumatic- and electromagnetic-CCI devices exist as do a variety of standard and custom injury induction tips. One of CCI's strengths is that it can be scaled to a number of common laboratory animals. Similarly, the CCI model can be used to produce graded TBI ranging from mild to severe. At the mild end of the injury spectrum, CCI has been applied in many ways, including to study open and closed head mTBI, repeated injuries, and the long-term deficits associated with mTBI and concussion. The purpose of this mini-review is to introduce the CCI model, discuss ways the model can be applied to study mTBI and concussion, and compare CCI to alternative pre-clinical TBI models.
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Affiliation(s)
- Nicole Osier
- School of Nursing, Holistic Adult Health Division, University of Texas at Austin, Austin, TX 78701, USA.
- Dell Medical School, Department of Neurology, University of Texas at Austin, Austin, TX 78701, USA.
| | - C Edward Dixon
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA 15224, USA.
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA 15260, USA.
- VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA.
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Yu F, Shukla DK, Armstrong RC, Marion CM, Radomski KL, Selwyn RG, Dardzinski BJ. Repetitive Model of Mild Traumatic Brain Injury Produces Cortical Abnormalities Detectable by Magnetic Resonance Diffusion Imaging, Histopathology, and Behavior. J Neurotrauma 2016; 34:1364-1381. [PMID: 27784203 PMCID: PMC5385606 DOI: 10.1089/neu.2016.4569] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Noninvasive detection of mild traumatic brain injury (mTBI) is important for evaluating acute through chronic effects of head injuries, particularly after repetitive impacts. To better detect abnormalities from mTBI, we performed longitudinal studies (baseline, 3, 6, and 42 days) using magnetic resonance diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) in adult mice after repetitive mTBI (r-mTBI; daily × 5) or sham procedure. This r-mTBI produced righting reflex delay and was first characterized in the corpus callosum to demonstrate low levels of axon damage, astrogliosis, and microglial activation, without microhemorrhages. High-resolution DTI-DKI was then combined with post-imaging pathological validation along with behavioral assessments targeted for the impact regions. In the corpus callosum, only DTI fractional anisotropy at 42 days showed significant change post-injury. Conversely, cortical regions under the impact site (M1–M2, anterior cingulate) had reduced axial diffusivity (AD) at all time points with a corresponding increase in axial kurtosis (Ka) at 6 days. Post-imaging neuropathology showed microglial activation in both the corpus callosum and cortex at 42 days after r-mTBI. Increased cortical microglial activation correlated with decreased cortical AD after r-mTBI (r = −0.853; n = 5). Using Thy1-YFP-16 mice to fluorescently label neuronal cell bodies and processes revealed low levels of axon damage in the cortex after r-mTBI. Finally, r-mTBI produced social deficits consistent with the function of this anterior cingulate region of cortex. Overall, vulnerability of cortical regions is demonstrated after mild repetitive injury, with underlying differences of DTI and DKI, microglial activation, and behavioral deficits.
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Affiliation(s)
- Fengshan Yu
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,2 Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Dinesh K Shukla
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,5 Department of Psychiatry, University of Maryland School of Medicine , Baltimore, Maryland
| | - Regina C Armstrong
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,2 Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,3 Program in Neuroscience, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Christina M Marion
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,3 Program in Neuroscience, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Kryslaine L Radomski
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,2 Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Reed G Selwyn
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,6 Department of Radiology, University of New Mexico , Albuquerque, New Mexico
| | - Bernard J Dardzinski
- 1 Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland.,4 Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences , Bethesda, Maryland
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31
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Chang EH, Adorjan I, Mundim MV, Sun B, Dizon MLV, Szele FG. Traumatic Brain Injury Activation of the Adult Subventricular Zone Neurogenic Niche. Front Neurosci 2016; 10:332. [PMID: 27531972 PMCID: PMC4969304 DOI: 10.3389/fnins.2016.00332] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/30/2016] [Indexed: 01/07/2023] Open
Abstract
Traumatic brain injury (TBI) is common in both civilian and military life, placing a large burden on survivors and society. However, with the recognition of neural stem cells in adult mammals, including humans, came the possibility to harness these cells for repair of damaged brain, whereas previously this was thought to be impossible. In this review, we focus on the rodent adult subventricular zone (SVZ), an important neurogenic niche within the mature brain in which neural stem cells continue to reside. We review how the SVZ is perturbed following various animal TBI models with regards to cell proliferation, emigration, survival, and differentiation, and we review specific molecules involved in these processes. Together, this information suggests next steps in attempting to translate knowledge from TBI animal models into human therapies for TBI.
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Affiliation(s)
- Eun Hyuk Chang
- Samsung Biomedical Research Institute, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd. Seoul, South Korea
| | - Istvan Adorjan
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK; Department of Anatomy, Histology and Embryology, Semmelweis UniversityBudapest, Hungary
| | - Mayara V Mundim
- Department of Biochemistry, Universidade Federal de São Paulo São Paulo, Brazil
| | - Bin Sun
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
| | - Maria L V Dizon
- Department of Pediatrics, Prentice Women's Hospital, Northwestern University Feinberg School of Medicine Chicago, IL, USA
| | - Francis G Szele
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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Honsa P, Valny M, Kriska J, Matuskova H, Harantova L, Kirdajova D, Valihrach L, Androvic P, Kubista M, Anderova M. Generation of reactive astrocytes from NG2 cells is regulated by sonic hedgehog. Glia 2016; 64:1518-31. [DOI: 10.1002/glia.23019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/10/2016] [Accepted: 05/26/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Pavel Honsa
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Martin Valny
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Jan Kriska
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Hana Matuskova
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Lenka Harantova
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Denisa Kirdajova
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Lukas Valihrach
- Laboratory of Gene Expression; Institute of Biotechnology, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Peter Androvic
- Laboratory of Gene Expression; Institute of Biotechnology, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Mikael Kubista
- Laboratory of Gene Expression; Institute of Biotechnology, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
| | - Miroslava Anderova
- Department of Cellular Neurophysiology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague 142 20 Czech Republic
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Hernandez A, Donovan V, Grinberg YY, Obenaus A, Carson MJ. Differential detection of impact site versus rotational site injury by magnetic resonance imaging and microglial morphology in an unrestrained mild closed head injury model. J Neurochem 2016; 136 Suppl 1:18-28. [PMID: 26806371 PMCID: PMC5047732 DOI: 10.1111/jnc.13402] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 01/31/2023]
Abstract
Seventy‐five percent of all traumatic brain injuries are mild and do not cause readily visible abnormalities on routine medical imaging making it difficult to predict which individuals will develop unwanted clinical sequelae. Microglia are brain‐resident macrophages and early responders to brain insults. Their activation is associated with changes in morphology or expression of phenotypic markers including P2Y12 and major histocompatibility complex class II. Using a murine model of unrestrained mild closed head injury (mCHI), we used microglia as reporters of acute brain injury at sites of impact versus sites experiencing rotational stress 24 h post‐mCHI. Consistent with mild injury, a modest 20% reduction in P2Y12 expression was detected by quantitative real‐time PCR (qPCR) analysis but only in the impacted region of the cortex. Furthermore, neither an influx of blood‐derived immune cells nor changes in microglial expression of CD45, TREM1, TREM2, major histocompatibility complex class II or CD40 were detected. Using magnetic resonance imaging (MRI), small reductions in T2 weighted values were observed but only near the area of impact and without overt tissue damage (blood deposition, edema). Microglial morphology was quantified without cryosectioning artifacts using ScaleA2 clarified brains from CX3CR1‐green fluorescence protein (GFP) mice. The cortex rostral to the mCHI impact site receives greater rotational stress but neither MRI nor molecular markers of microglial activation showed significant changes from shams in this region. However, microglia in this rostral region did display signs of morphologic activation equivalent to that observed in severe CHI. Thus, mCHI‐triggered rotational stress is sufficient to cause injuries undetectable by routine MRI that could result in altered microglial surveillance of brain homeostasis.
Acute changes in microglial morphology reveal brain responses to unrestrained mild traumatic brain injury
In areas subjected to rotational stress distant from impact site In the absence of detectable changes in standard molecular indicators of brain damage, inflammation or microglial activation. That might result in decreased surveillance of brain function and increased susceptibility to subsequent brain insults.
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Affiliation(s)
- Alfredo Hernandez
- Center for Glial-Neuronal Interactions, University of California Riverside, School of Medicine, Riverside, California, USA.,MarcU Program, University of California Riverside, Riverside, California, USA.,Division of Biomedical Sciences, University of California Riverside, School of Medicine, Riverside, California, USA
| | - Virgina Donovan
- Center for Glial-Neuronal Interactions, University of California Riverside, School of Medicine, Riverside, California, USA.,Division of Biomedical Sciences, University of California Riverside, School of Medicine, Riverside, California, USA.,Cell Molecular and Developmental Biology Program, University of California Riverside, Riverside, California, USA.,Loma Linda University School of Medicine, Loma Linda California, Loma Linda, CA, USA
| | - Yelena Y Grinberg
- Center for Glial-Neuronal Interactions, University of California Riverside, School of Medicine, Riverside, California, USA.,Division of Biomedical Sciences, University of California Riverside, School of Medicine, Riverside, California, USA
| | - Andre Obenaus
- Center for Glial-Neuronal Interactions, University of California Riverside, School of Medicine, Riverside, California, USA.,Cell Molecular and Developmental Biology Program, University of California Riverside, Riverside, California, USA.,Loma Linda University School of Medicine, Loma Linda California, Loma Linda, CA, USA
| | - Monica J Carson
- Center for Glial-Neuronal Interactions, University of California Riverside, School of Medicine, Riverside, California, USA.,Division of Biomedical Sciences, University of California Riverside, School of Medicine, Riverside, California, USA.,Cell Molecular and Developmental Biology Program, University of California Riverside, Riverside, California, USA
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Acute Traumatic Brain Injury Does Not Exacerbate Amyotrophic Lateral Sclerosis in the SOD1 (G93A) Rat Model. eNeuro 2015; 2:eN-NWR-0059-14. [PMID: 26464984 PMCID: PMC4586929 DOI: 10.1523/eneuro.0059-14.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 05/17/2015] [Accepted: 05/21/2015] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease in which upper and lower motor neurons degenerate, leading to muscle atrophy, paralysis, and death within 3 to 5 years of onset. While a small percentage of ALS cases are genetically linked, the majority are sporadic with unknown origin. Currently, etiological links are associated with disease onset without mechanistic understanding. Of all the putative risk factors, however, head trauma has emerged as a consistent candidate for initiating the molecular cascades of ALS. Here, we test the hypothesis that traumatic brain injury (TBI) in the SOD1G93A transgenic rat model of ALS leads to early disease onset and shortened lifespan. We demonstrate, however, that a one-time acute focal injury caused by controlled cortical impact does not affect disease onset or survival. Establishing the negligible involvement of a single acute focal brain injury in an ALS rat model increases the current understanding of the disease. Critically, untangling a single focal TBI from multiple mild injuries provides a rationale for scientists and physicians to increase focus on repeat injuries to hopefully pinpoint a contributing cause of ALS.
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Armstrong RC, Mierzwa AJ, Sullivan GM, Sanchez MA. Myelin and oligodendrocyte lineage cells in white matter pathology and plasticity after traumatic brain injury. Neuropharmacology 2015; 110:654-659. [PMID: 25963414 DOI: 10.1016/j.neuropharm.2015.04.029] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/13/2015] [Accepted: 04/27/2015] [Indexed: 12/14/2022]
Abstract
Impact to the head or rapid head acceleration-deceleration can cause traumatic brain injury (TBI) with a characteristic pathology of traumatic axonal injury (TAI) and secondary damage in white matter tracts. Myelin and oligodendrocyte lineage cells have significant roles in the progression of white matter pathology after TBI and in the potential for plasticity and subsequent recovery. The myelination pattern of specific brain regions, such as frontal cortex, may also increase susceptibility to neurodegeneration and psychiatric symptoms after TBI. White matter pathology after TBI depends on the extent and distribution of axon damage, microhemorrhages and/or neuroinflammation. TAI occurs in a pattern of damaged axons dispersed among intact axons in white matter tracts. TAI accompanied by bleeding and/or inflammation produces focal regions of overt tissue destruction, resulting in loss of both axons and myelin. White matter regions with TAI may also exhibit demyelination of intact axons. Demyelinated axons that remain viable have the potential for remyelination and recovery of function. Indeed, animal models of TBI have demonstrated demyelination that is associated with evidence of remyelination, including oligodendrocyte progenitor cell proliferation, generation of new oligodendrocytes, and formation of thinner myelin. Changes in neuronal activity that accompany TBI may also involve myelin remodeling, which modifies conduction efficiency along intact myelinated fibers. Thus, effective remyelination and myelin remodeling may be neurobiological substrates of plasticity in neuronal circuits that require long-distance communication. This perspective integrates findings from multiple contexts to propose a model of myelin and oligodendrocyte lineage cell relevance in white matter injury after TBI. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Affiliation(s)
- Regina C Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Amanda J Mierzwa
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Genevieve M Sullivan
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Maria A Sanchez
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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Components of myelin damage and repair in the progression of white matter pathology after mild traumatic brain injury. J Neuropathol Exp Neurol 2015; 74:218-32. [PMID: 25668562 PMCID: PMC4327393 DOI: 10.1097/nen.0000000000000165] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
White matter tracts are highly vulnerable to damage from impact-acceleration forces of traumatic brain injury (TBI). Mild TBI is characterized by a low density of traumatic axonal injury, whereas associated myelin pathology is relatively unexplored. We examined the progression of white matter pathology in mice after mild TBI with traumatic axonal injury localized in the corpus callosum. Adult mice received a closed-skull impact and were analyzed from 3 days to 6 weeks post-TBI/sham surgery. At all times post-TBI, electron microscopy revealed degenerating axons distributed among intact fibers in the corpus callosum. Intact axons exhibited significant demyelination at 3 days followed by evidence of remyelination at 1 week. Accordingly, bromodeoxyuridine pulse-chase labeling demonstrated the generation of new oligodendrocytes, identified by myelin proteolipid protein messenger RNA expression, at 3 days post-TBI. Overall oligodendrocyte populations, identified by immunohistochemical staining for CC1 and/or glutathione S-transferase pi, were similar between TBI and sham mice by 2 weeks. Excessively long myelin figures, similar to redundant myelin sheaths, were a significant feature at all post-TBI time points. At 6 weeks post-TBI, microglial activation and astrogliosis were localized to areas of axon and myelin pathology. These studies show that demyelination, remyelination, and excessive myelin are components of white matter degeneration and recovery in mild TBI with traumatic axonal injury.
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Ruat M, Faure H, Daynac M. Smoothened, Stem Cell Maintenance and Brain Diseases. TOPICS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1007/7355_2014_83] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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