1
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Benarroch E. What Are the Roles of Oligodendrocyte Precursor Cells in Normal and Pathologic Conditions? Neurology 2023; 101:958-965. [PMID: 37985182 PMCID: PMC10663025 DOI: 10.1212/wnl.0000000000208000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 11/22/2023] Open
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2
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Gakare SG, Bhatt JM, Narasimhan KKS, Dravid SM. Glutamate delta-1 receptor regulates oligodendrocyte progenitor cell differentiation and myelination in normal and demyelinating conditions. PLoS One 2023; 18:e0294583. [PMID: 37983226 PMCID: PMC10659214 DOI: 10.1371/journal.pone.0294583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/05/2023] [Indexed: 11/22/2023] Open
Abstract
In this study, we investigated the role of glutamate delta 1 receptor (GluD1) in oligodendrocyte progenitor cell (OPC)-mediated myelination during basal (development) and pathophysiological (cuprizone-induced demyelination) conditions. Initially, we sought to determine the expression pattern of GluD1 in OPCs and found a significant colocalization of GluD1 puncta with neuron-glial antigen 2 (NG2, OPC marker) in the motor cortex and dorsal striatum. Importantly, we found that the ablation of GluD1 led to an increase in the number of myelin-associated glycoprotein (MAG+) cells in the corpus callosum and motor cortex at P40 without affecting the number of NG2+ OPCs, suggesting that GluD1 loss selectively facilitates OPC differentiation rather than proliferation. Further, deletion of GluD1 enhanced myelination in the corpus callosum and motor cortex, as indicated by increased myelin basic protein (MBP) staining at P40, suggesting that GluD1 may play an essential role in the developmental regulation of myelination during the critical window period. In contrast, in cuprizone-induced demyelination, we observed reduced MBP staining in the corpus callosum of GluD1 KO mice. Furthermore, cuprizone-fed GluD1 KO mice showed more robust motor deficits. Collectively, our results demonstrate that GluD1 plays a critical role in OPC regulation and myelination in normal and demyelinating conditions.
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Affiliation(s)
- Sukanya G. Gakare
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States of America
| | - Jay M. Bhatt
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States of America
| | - Kishore Kumar S. Narasimhan
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States of America
| | - Shashank M. Dravid
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States of America
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3
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Vuong A, Joshi SH, Staudt LA, Matsumoto JH, Fowler EG. Improved Myelination following Camp Leg Power, a Selective Motor Control Intervention for Children with Spastic Bilateral Cerebral Palsy: A Diffusion Tensor MRI Study. AJNR Am J Neuroradiol 2023; 44:700-706. [PMID: 37142433 PMCID: PMC10249693 DOI: 10.3174/ajnr.a7860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 04/04/2023] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND PURPOSE Children with spastic cerebral palsy have motor deficits associated with periventricular leukomalacia indicating WM damage to the corticospinal tracts. We investigated whether practice of skilled lower extremity selective motor control movements would elicit neuroplasticity. MATERIALS AND METHODS Twelve children with spastic bilateral cerebral palsy and periventricular leukomalacia born preterm (mean age, 11.5 years; age range, 7.3-16.6 years) participated in a lower extremity selective motor control intervention, Camp Leg Power. Activities promoted isolated joint movement including isokinetic knee exercises, ankle-controlled gaming, gait training, and sensorimotor activities (3 hours/day, 15 sessions, 1 month). DWI scans were collected pre- and postintervention. Tract-Based Spatial Statistics was used to analyze changes in fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity. RESULTS Significantly reduced radial diffusivity (P < . 05) was found within corticospinal tract ROIs, including 28.4% of the left and 3.6% of the right posterior limb of the internal capsule and 14.1% of the left superior corona radiata. Reduced mean diffusivity was found within the same ROIs (13.3%, 11.6%, and 6.6%, respectively). Additionally, decreased radial diffusivity was observed in the left primary motor cortex. Additional WM tracts had decreased radial diffusivity and mean diffusivity, including the anterior limb of the internal capsule, external capsule, anterior corona radiata, and corpus callosum body and genu. CONCLUSIONS Myelination of the corticospinal tracts improved following Camp Leg Power. Neighboring WM changes suggest recruitment of additional tracts involved in regulating neuroplasticity of the motor regions. Intensive practice of skilled lower extremity selective motor control movements promotes neuroplasticity in children with spastic bilateral cerebral palsy.
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Affiliation(s)
- A Vuong
- From the Departments of Bioengineering (A.V., S.H.J.)
- Orthopaedic Surgery (A.V., L.A.S., E.G.F.)
- Center for Cerebral Palsy (A.V., L.A.S., E.G.F.), University of California Los Angeles/Orthopaedic Institute for Children, Los Angeles, California
| | - S H Joshi
- From the Departments of Bioengineering (A.V., S.H.J.)
- Neurology (S.H.J.), Ahmanson Lovelace Brain Mapping Center
| | - L A Staudt
- Orthopaedic Surgery (A.V., L.A.S., E.G.F.)
- Center for Cerebral Palsy (A.V., L.A.S., E.G.F.), University of California Los Angeles/Orthopaedic Institute for Children, Los Angeles, California
| | - J H Matsumoto
- Pediatrics (J.H.M.), University of California Los Angeles, Los Angeles, California
| | - E G Fowler
- Orthopaedic Surgery (A.V., L.A.S., E.G.F.)
- Center for Cerebral Palsy (A.V., L.A.S., E.G.F.), University of California Los Angeles/Orthopaedic Institute for Children, Los Angeles, California
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4
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Surgent O, Guerrero-Gonzalez J, Dean DC, Kirk GR, Adluru N, Kecskemeti SR, Alexander AL, Travers BG. How we get a grip: Microstructural neural correlates of manual grip strength in children. Neuroimage 2023; 273:120117. [PMID: 37062373 PMCID: PMC10161685 DOI: 10.1016/j.neuroimage.2023.120117] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/23/2023] [Accepted: 04/13/2023] [Indexed: 04/18/2023] Open
Abstract
Maximal grip strength is associated with a variety of health-related outcome measures and thus may be reflective of the efficiency of foundational brain-body communication. Non-human primate models of grip strength strongly implicate the cortical lateral grasping network, but little is known about the translatability of these models to human children. Further, it is unclear how supplementary networks that provide proprioceptive information and cerebellar-based motor command modification are associated with maximal grip strength. Therefore, this study employed high resolution, multi-shell diffusion and quantitative T1 imaging to examine how variations in lateral grasping, proprioception input, and cortico-cerebellar modification network white matter microstructure are associated with variations in grip strength across 70 children. Results indicated that stronger grip strength was associated with higher lateral grasping and proprioception input network fractional anisotropy and R1, indirect measures consistent with stronger microstructural coherence and increased myelination. No relationships were found in the cerebellar modification network. These results provide a neurobiological mechanism of grip behavior in children which suggests that increased myelination of cortical sensory and motor pathways is associated with stronger grip. This neurobiological mechanism may be a signature of pediatric neuro-motor behavior more broadly as evidenced by the previously demonstrated relationships between grip strength and behavioral outcome measures across a variety of clinical and non-clinical populations.
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Affiliation(s)
- Olivia Surgent
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States
| | - Jose Guerrero-Gonzalez
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Douglas C Dean
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, United States
| | - Gregory R Kirk
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Nagesh Adluru
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Andrew L Alexander
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States; Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States
| | - Brittany G Travers
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States; Occupational Therapy Program in the Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States.
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5
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Paquola C, Hong SJ. The Potential of Myelin-Sensitive Imaging: Redefining Spatiotemporal Patterns of Myeloarchitecture. Biol Psychiatry 2023; 93:442-454. [PMID: 36481065 DOI: 10.1016/j.biopsych.2022.08.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/12/2022] [Accepted: 08/30/2022] [Indexed: 02/07/2023]
Abstract
Recent advances in magnetic resonance imaging (MRI) have paved the way for approximation of myelin content in vivo. In this review, our main goal was to determine how to best capitalize on myelin-sensitive imaging. First, we briefly overview the theoretical and empirical basis for the myelin sensitivity of different MRI markers and, in doing so, highlight how multimodal imaging approaches are important for enhancing specificity to myelin. Then, we discuss recent studies that have probed the nonuniform distribution of myelin across cortical layers and along white matter tracts. These approaches, collectively known as myelin profiling, have provided detailed depictions of myeloarchitecture in both the postmortem and living human brain. Notably, MRI-based profiling studies have recently focused on investigating whether it can capture interindividual variability in myelin characteristics as well as trajectories across the lifespan. Finally, another line of recent evidence emphasizes the contribution of region-specific myelination to large-scale organization, demonstrating the impact of myelination on global brain networks. In conclusion, we suggest that combining well-validated MRI markers with profiling techniques holds strong potential to elucidate individual differences in myeloarchitecture, which has important implications for understanding brain function and disease.
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Affiliation(s)
- Casey Paquola
- Institute of Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany.
| | - Seok-Jun Hong
- Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University, Suwon, South Korea; Center for the Developing Brain, Child Mind Institute, New York, New York; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
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6
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Ao Q, Wen LL, Yu TH, Ma YZ, Mao XY, Ao TR, Javed R, Ten H, Matsuno A. Sequential expression of miR-221-3p and miR-338-3p in Schwann cells as a therapeutic strategy to promote nerve regeneration and functional recovery. Neural Regen Res 2023; 18:671-682. [DOI: 10.4103/1673-5374.350214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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7
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Mani A, Salinas I. The knowns and many unknowns of CNS immunity in teleost fish. FISH & SHELLFISH IMMUNOLOGY 2022; 131:431-440. [PMID: 36241002 DOI: 10.1016/j.fsi.2022.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Many disease agents infect the central nervous system (CNS) of teleost fish causing severe losses for the fish farming sector. Yet, neurotropic fish pathogens remain poorly documented and immune responses in the teleost CNS essentially unknown. Previously thought to be devoid of an immune system, the mammalian CNS is now recognized to be protected from infection by diverse immune cells that mostly reside in the meningeal lymphatic system. Here we review the current body of work pertaining immune responses in the teleost CNS to infection. We identify important knowledge gaps with regards to CNS immunity in fish and make recommendations for rigorous experimentation and reporting in manuscripts so that fish immunologists can advance this burgeoning field.
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Affiliation(s)
- Amir Mani
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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8
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Sobel RA, Albertelli M, Hinojoza JR, Eaton MJ, Grimes KV, Rubenstein E. Azetidine-2-Carboxylic Acid-Induced Oligodendrogliopathy: Relevance to the Pathogenesis of Multiple Sclerosis. J Neuropathol Exp Neurol 2022; 81:414-433. [PMID: 35521963 PMCID: PMC9123080 DOI: 10.1093/jnen/nlac028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The naturally occurring imino acid azetidine-2-carboxylic acid (Aze) is consumed by humans and can be misincorporated in place of proline in myelin basic protein (MBP) in vitro. To determine Aze effects on the mammalian CNS in vivo, adult CD1 mice were given Aze orally or intraperitoneally. Clinical signs reminiscent of MBP-mutant mice occurred with 600 mg/kg Aze exposure. Aze induced oligodendrocyte (OL) nucleomegaly and nucleoplasm clearing, dilated endoplasmic reticulum, cytoplasmic vacuolation, abnormal mitochondria, and Aze dose-dependent apoptosis. Immunohistochemistry demonstrated myelin blistering and nuclear translocation of unfolded protein response (UPR)/proinflammatory molecules (ATF3, ATF4, ATF6, eIF2α, GADD153, NFκB, PERK, XBP1), MHC I expression, and MBP cytoplasmic aggregation in OL. There were scattered microglial nodules in CNS white matter (WM); other CNS cells appeared unaffected. Mice given Aze in utero and postnatally showed more marked effects than their dams. These OL, myelin, and microglial alterations are found in normal-appearing WM (NAWM) in multiple sclerosis (MS) patients. Thus, Aze induces a distinct oligodendrogliopathy in mice that recapitulates MS NAWM pathology without leukocyte infiltration. Because myelin proteins are relatively stable throughout life, we hypothesize that Aze misincorporation in myelin proteins during myelinogenesis in humans results in a progressive UPR that may be a primary process in MS pathogenesis.
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Affiliation(s)
- Raymond A Sobel
- From the Laboratory Service, Veterans Affairs Health Care System, Palo Alto, California, USA.,Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Megan Albertelli
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Julian R Hinojoza
- From the Laboratory Service, Veterans Affairs Health Care System, Palo Alto, California, USA.,Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Mary Jane Eaton
- From the Laboratory Service, Veterans Affairs Health Care System, Palo Alto, California, USA.,Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Kevin V Grimes
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Edward Rubenstein
- Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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9
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Lam SM, Li J, Sun H, Mao W, Liu Z, Zhao Q, Han C, Gong X, Jiang B, Chua GH, Zhao Z, Meng F, Shui G. Quantitative lipidomics and spatial MS-Imaging uncovered neurological and systemic lipid metabolic pathways underlying troglomorphic adaptations in cave-dwelling fish. Mol Biol Evol 2022; 39:6547622. [PMID: 35277964 PMCID: PMC9011034 DOI: 10.1093/molbev/msac050] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Sinocyclocheilus represents a rare, freshwater teleost genus endemic to China that comprises the river-dwelling surface fish and the cave-dwelling cavefish. Using a combinatorial approach of quantitative lipidomics and mass-spectrometry imaging (MSI), we demonstrated that neural compartmentalization of lipid distribution and lipid metabolism are associated with the evolution of troglomorphic traits in Sinocyclocheilus. Attenuated DHA biosynthesis via the Δ4 desaturase pathway led to reductions in docosahexaenoic acid (DHA)-phospholipids in cavefish cerebellum. Instead, cavefish accumulates arachidonic acid (ARA)-phospholipids that may disfavor retinotectal arbor growth. Importantly, MSI of sulfatides, coupled with immunostaining of myelin basic protein and transmission electron microscopy images of hindbrain axons revealed demyelination in cavefish raphe serotonergic neurons. Demyelination in cavefish parallels the loss of neuroplasticity governing social behavior such as aggressive dominance. Outside the brain, quantitative lipidomics and qRT-PCR revealed systemic reductions in membrane esterified DHAs in the liver, attributed to suppression of genes along the Sprecher pathway (elovl2, elovl5, acox1). Development of fatty livers was observed in cavefish, likely mediated by an impeded mobilization of storage lipids, as evident in the diminished expressions of pnpla2, lipea, lipeb, dagla and mgll; and suppressed β-oxidation of fatty acyls via both mitochondria and peroxisomes, reflected in the reduced expressions of cpt1ab, hadhaa, cpt2, decr1 and acox1. These neurological and systemic metabolic adaptations serve to reduce energy expenditure, forming the basis of recessive evolution that eliminates non-essential morphological and behavioral traits, giving cavefish a selective advantage to thrive in caves where proper resource allocation becomes a major determinant of survival.
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Affiliation(s)
- Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Jie Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huan Sun
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weining Mao
- Qujing Aquaculture Station, Qujing 655000, Yunan Province, China
| | - Zongmin Liu
- Qujing Aquaculture Station, Qujing 655000, Yunan Province, China
| | - Qingshuo Zhao
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chao Han
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing Mass Spectrum Center, Beijing, China
| | - Xia Gong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Binhua Jiang
- LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Gek Huey Chua
- LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Zhenwen Zhao
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing Mass Spectrum Center, Beijing, China
| | - Fanwei Meng
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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10
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11
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Cruz-Méndez JS, Herrera-Sánchez MP, Céspedes-Rubio ÁE, Rondón-Barragán IS. Molecular characterization of myelin basic protein a (mbpa) gene from red-bellied pacu (Piaractus brachypomus). JOURNAL OF GENETIC ENGINEERING AND BIOTECHNOLOGY 2022; 20:8. [PMID: 35024999 PMCID: PMC8758815 DOI: 10.1186/s43141-022-00296-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/04/2022] [Indexed: 12/18/2022]
Abstract
Background Myelin basic protein (MBP) is one of the most important structural components of the myelin sheaths in both central and peripheral nervous systems. MBP has several functions including organization of the myelin membranes, reorganization of the cytoskeleton during the myelination process, and interaction with the SH3 domain in signaling pathways. Likewise, MBP has been proposed as a marker of demyelination in traumatic brain injury and chemical exposure. Methods The aim of this study was to molecularly characterize the myelin basic protein a (mbpa) gene from the Colombian native fish, red-bellied pacu, Piaractus brachypomus. Bioinformatic tools were used to identify the phylogenetic relationships, physicochemical characteristics, exons, intrinsically disordered regions, and conserved domains of the protein. Gene expression was assessed by qPCR in three models corresponding to sublethal chlorpyrifos exposure, acute brain injury, and anesthesia experiments. Results mbpa complete open reading frame was identified with 414 nucleotides distributed in 7 exons that encode 137 amino acids. MBPa was recognized as belonging to the myelin basic protein family, closely related with orthologous proteins, and two intrinsically disordered regions were established within the sequence. Gene expression of mbpa was upregulated in the optic chiasm of the chlorpyrifos exposed fish in contrast to the control group. Conclusions The physicochemical computed features agree with the biological functions of MBP, and basal gene expression was according to the anatomical distribution in the tissues analyzed. This study is the first molecular characterization of mbpa from the native species Piaractus brachypomus.
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Affiliation(s)
- Juan Sebastian Cruz-Méndez
- Research Group in Immunobiology and Pathogenesis, Laboratory of Immunology and Molecular Biology, Faculty of Veterinary Medicine and Zootechnics, Universidad del Tolima, Santa Helena Highs, 730006299, Ibague, Tolima, Colombia
| | - María Paula Herrera-Sánchez
- Research Group in Immunobiology and Pathogenesis, Laboratory of Immunology and Molecular Biology, Faculty of Veterinary Medicine and Zootechnics, Universidad del Tolima, Santa Helena Highs, 730006299, Ibague, Tolima, Colombia
| | - Ángel Enrique Céspedes-Rubio
- Research Group in Neurodegenerative Diseases, Faculty of Veterinary Medicine and Zootechnics, Universidad del Tolima, Santa Helena Highs, 730006299, Ibague, Tolima, Colombia
| | - Iang Schroniltgen Rondón-Barragán
- Research Group in Immunobiology and Pathogenesis, Laboratory of Immunology and Molecular Biology, Faculty of Veterinary Medicine and Zootechnics, Universidad del Tolima, Santa Helena Highs, 730006299, Ibague, Tolima, Colombia. .,Research Group in Neurodegenerative Diseases, Faculty of Veterinary Medicine and Zootechnics, Universidad del Tolima, Santa Helena Highs, 730006299, Ibague, Tolima, Colombia. .,Laboratory of Immunology and Molecular Biology, Department of Animal Health, Faculty of Veterinary Medicine and Zootechnics, University of Tolima, Ibague, 730006299, Colombia.
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12
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Hines JH. Evolutionary Origins of the Oligodendrocyte Cell Type and Adaptive Myelination. Front Neurosci 2021; 15:757360. [PMID: 34924932 PMCID: PMC8672417 DOI: 10.3389/fnins.2021.757360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/29/2021] [Indexed: 12/23/2022] Open
Abstract
Oligodendrocytes are multifunctional central nervous system (CNS) glia that are essential for neural function in gnathostomes. The evolutionary origins and specializations of the oligodendrocyte cell type are among the many remaining mysteries in glial biology and neuroscience. The role of oligodendrocytes as CNS myelinating glia is well established, but recent studies demonstrate that oligodendrocytes also participate in several myelin-independent aspects of CNS development, function, and maintenance. Furthermore, many recent studies have collectively advanced our understanding of myelin plasticity, and it is now clear that experience-dependent adaptations to myelination are an additional form of neural plasticity. These observations beg the questions of when and for which functions the ancestral oligodendrocyte cell type emerged, when primitive oligodendrocytes evolved new functionalities, and the genetic changes responsible for these evolutionary innovations. Here, I review recent findings and propose working models addressing the origins and evolution of the oligodendrocyte cell type and adaptive myelination. The core gene regulatory network (GRN) specifying the oligodendrocyte cell type is also reviewed as a means to probe the existence of oligodendrocytes in basal vertebrates and chordate invertebrates.
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Affiliation(s)
- Jacob H. Hines
- Biology Department, Winona State University, Winona, MN, United States
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13
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Neely SA, Lyons DA. Insights Into Central Nervous System Glial Cell Formation and Function From Zebrafish. Front Cell Dev Biol 2021; 9:754606. [PMID: 34912801 PMCID: PMC8666443 DOI: 10.3389/fcell.2021.754606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/23/2022] Open
Abstract
The term glia describes a heterogenous collection of distinct cell types that make up a large proportion of our nervous system. Although once considered the glue of the nervous system, the study of glial cells has evolved significantly in recent years, with a large body of literature now highlighting their complex and diverse roles in development and throughout life. This progress is due, in part, to advances in animal models in which the molecular and cellular mechanisms of glial cell development and function as well as neuron-glial cell interactions can be directly studied in vivo in real time, in intact neural circuits. In this review we highlight the instrumental role that zebrafish have played as a vertebrate model system for the study of glial cells, and discuss how the experimental advantages of the zebrafish lend themselves to investigate glial cell interactions and diversity. We focus in particular on recent studies that have provided insight into the formation and function of the major glial cell types in the central nervous system in zebrafish.
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Affiliation(s)
- Sarah A. Neely
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David A. Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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14
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Turan F, Yilmaz Ö, Schünemann L, Lindenberg TT, Kalanithy JC, Harder A, Ahmadi S, Duman T, MacDonald RB, Winter D, Liu C, Odermatt B. Effect of modulating glutamate signaling on myelinating oligodendrocytes and their development-A study in the zebrafish model. J Neurosci Res 2021; 99:2774-2792. [PMID: 34520578 DOI: 10.1002/jnr.24940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 07/12/2021] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Myelination is crucial for the development and maintenance of axonal integrity, especially fast axonal action potential conduction. There is increasing evidence that glutamate signaling and release through neuronal activity modulates the myelination process. In this study, we examine the effect of manipulating glutamate signaling on myelination of oligodendrocyte (OL) lineage cells and their development in zebrafish (zf). We use the "intensity-based glutamate-sensing fluorescent reporter" (iGluSnFR) in the zf model (both sexes) to address the hypothesis that glutamate is implicated in regulation of myelinating OLs. Our results show that glial iGluSnFR expression significantly reduces OL lineage cell number and the expression of myelin markers in larvae (zfl) and adult brains. The specific glutamate receptor agonist, L-AP4, rescues this iGluSnFR effect by significantly increasing the expression of the myelin-related genes, plp1b and mbpa, and enhances myelination in L-AP4-injected zfl compared to controls. Furthermore, we demonstrate that degrading glutamate using Glutamat-Pyruvate Transaminase (GPT) or the blockade of glutamate reuptake by L-trans-pyrrolidine-2,4-dicarboxylate (PDC) significantly decreases myelin-related genes and drastically declines myelination in brain ventricle-injected zfl. Moreover, we found that myelin-specific ClaudinK (CldnK) and 36K protein expression is significantly decreased in iGluSnFR-expressing zfl and adult brains compared to controls. Taken together, this study confirms that glutamate signaling is directly required for the preservation of myelinating OLs and for the myelination process itself. These findings further suggest that glutamate signaling may provide novel targets to therapeutically boost remyelination in several demyelinating diseases of the CNS.
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Affiliation(s)
- Funda Turan
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany.,Faculty of Science, Biology Department, Ankara University, Ankara, Turkey
| | - Öznur Yilmaz
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Lena Schünemann
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Tobias T Lindenberg
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany
| | - Jeshurun C Kalanithy
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Alexander Harder
- Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Shiva Ahmadi
- Medical Faculty, Institute for Biochemistry and Molecular Biology (IBMB), University of Bonn, Bonn, Germany
| | - Türker Duman
- Faculty of Science, Biology Department, Ankara University, Ankara, Turkey
| | - Ryan B MacDonald
- Institute of Ophthalmology, University College London, London, UK
| | - Dominic Winter
- Medical Faculty, Institute for Biochemistry and Molecular Biology (IBMB), University of Bonn, Bonn, Germany
| | - Changsheng Liu
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Benjamin Odermatt
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany.,Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
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15
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Ding Q, Jia Y. Effects of temperature and ion channel blocks on propagation of action potential in myelinated axons. CHAOS (WOODBURY, N.Y.) 2021; 31:053102. [PMID: 34240929 DOI: 10.1063/5.0044874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/14/2021] [Indexed: 06/13/2023]
Abstract
Potassium ion and sodium ion channels play important roles in the propagation of action potentials along a myelinated axon. The random opening and closing of ion channels can cause the fluctuation of action potentials. In this paper, an improved Hodgkin-Huxley chain network model is proposed to study the effects of ion channel blocks, temperature, and ion channel noise on the propagation of action potentials along the myelinated axon. It is found that the chain network has minimum coupling intensity threshold and maximum tolerance temperature threshold that allow the action potentials to pass along the whole axon, and the blockage of ion channels can change these two thresholds. A striking result is that the simulated value of the optimum membrane size (inversely proportional to noise intensity) coincides with the area range of feline thalamocortical relay cells in biological experiments.
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Affiliation(s)
- Qianming Ding
- Department of Physics, Central China Normal University, Wuhan 430079, China
| | - Ya Jia
- Department of Physics, Central China Normal University, Wuhan 430079, China
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16
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Nishiyama A, Shimizu T, Sherafat A, Richardson WD. Life-long oligodendrocyte development and plasticity. Semin Cell Dev Biol 2021; 116:25-37. [PMID: 33741250 PMCID: PMC8292179 DOI: 10.1016/j.semcdb.2021.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/25/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) originate in localized germinal zones in the embryonic neural tube, then migrate and proliferate to populate the entire central nervous system, both white and gray matter. They divide and generate myelinating oligodendrocytes (OLs) throughout postnatal and adult life. OPCs express NG2 and platelet-derived growth factor receptor alpha subunit (PDGFRα), two functionally important cell surface proteins, which are also widely used as markers for OPCs. The proliferation of OPCs, their terminal differentiation into OLs, survival of new OLs, and myelin synthesis are orchestrated by signals in the local microenvironment. We discuss advances in our mechanistic understanding of paracrine effects, including those mediated through PDGFRα and neuronal activity-dependent signals such as those mediated through AMPA receptors in OL survival and myelination. Finally, we review recent studies supporting the role of new OL production and “adaptive myelination” in specific behaviours and cognitive processes contributing to learning and long-term memory formation. Our article is not intended to be comprehensive but reflects the authors’ past and present interests.
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Affiliation(s)
- Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269-3156, USA.
| | - Takahiro Shimizu
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Amin Sherafat
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269-3156, USA
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
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17
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Möbius W, Hümmert S, Ruhwedel T, Kuzirian A, Gould R. New Species Can Broaden Myelin Research: Suitability of Little Skate, Leucoraja erinacea. Life (Basel) 2021; 11:136. [PMID: 33670172 PMCID: PMC7916940 DOI: 10.3390/life11020136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/02/2021] [Accepted: 02/06/2021] [Indexed: 02/06/2023] Open
Abstract
Although myelinated nervous systems are shared among 60,000 jawed vertebrates, studies aimed at understanding myelination have focused more and more on mice and zebrafish. To obtain a broader understanding of the myelination process, we examined the little skate, Leucoraja erinacea. The reasons behind initiating studies at this time include: the desire to study a species belonging to an out group of other jawed vertebrates; using a species with embryos accessible throughout development; the availability of genome sequences; and the likelihood that mammalian antibodies recognize homologs in the chosen species. We report that the morphological features of myelination in a skate hatchling, a stage that supports complex behavioral repertoires needed for survival, are highly similar in terms of: appearances of myelinating oligodendrocytes (CNS) and Schwann cells (PNS); the way their levels of myelination conform to axon caliber; and their identity in terms of nodal and paranodal specializations. These features provide a core for further studies to determine: axon-myelinating cell communication; the structures of the proteins and lipids upon which myelinated fibers are formed; the pathways used to transport these molecules to sites of myelin assembly and maintenance; and the gene regulatory networks that control their expressions.
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Affiliation(s)
- Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
- Cluster of Excellence Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC), University of Göttingen, 37073 Göttingen, Germany
| | - Sophie Hümmert
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
| | - Torben Ruhwedel
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
| | - Alan Kuzirian
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02540, USA;
| | - Robert Gould
- Whitman Science Center, Marin Biological Laboratory, Woods Hole, MA 02540, USA
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18
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Danesin C, Darche-Gabinaud R, Escalas N, Bouguetoch V, Cochard P, Al Oustah A, Ohayon D, Glise B, Soula C. Sulf2a controls Shh-dependent neural fate specification in the developing spinal cord. Sci Rep 2021; 11:118. [PMID: 33420239 PMCID: PMC7794431 DOI: 10.1038/s41598-020-80455-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/16/2020] [Indexed: 12/31/2022] Open
Abstract
Sulf2a belongs to the Sulf family of extracellular sulfatases which selectively remove 6-O-sulfate groups from heparan sulfates, a critical regulation level for their role in modulating the activity of signalling molecules. Data presented here define Sulf2a as a novel player in the control of Sonic Hedgehog (Shh)-mediated cell type specification during spinal cord development. We show that Sulf2a depletion in zebrafish results in overproduction of V3 interneurons at the expense of motor neurons and also impedes generation of oligodendrocyte precursor cells (OPCs), three cell types that depend on Shh for their generation. We provide evidence that Sulf2a, expressed in a spatially restricted progenitor domain, acts by maintaining the correct patterning and specification of ventral progenitors. More specifically, Sulf2a prevents Olig2 progenitors to activate high-threshold Shh response and, thereby, to adopt a V3 interneuron fate, thus ensuring proper production of motor neurons and OPCs. We propose a model in which Sulf2a reduces Shh signalling levels in responding cells by decreasing their sensitivity to the morphogen factor. More generally, our work, revealing that, in contrast to its paralog Sulf1, Sulf2a regulates neural fate specification in Shh target cells, provides direct evidence of non-redundant functions of Sulfs in the developing spinal cord.
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Affiliation(s)
- Cathy Danesin
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France.
| | - Romain Darche-Gabinaud
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Nathalie Escalas
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Vanessa Bouguetoch
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Philippe Cochard
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Amir Al Oustah
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - David Ohayon
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Bruno Glise
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
| | - Cathy Soula
- Centre de Biologie Intégrative (CBI), Centre de Biologie du Développement (CBD), Université de Toulouse, CNRS (UMR 5547), Toulouse, France
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19
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Neuronal activity-dependent myelin repair promotes motor function recovery after contusion spinal cord injury. Brain Res Bull 2020; 166:73-81. [PMID: 33197536 DOI: 10.1016/j.brainresbull.2020.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 10/09/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022]
Abstract
An increasing number of studies connect neuronal activity with developmental myelination but how neuronal activity regulates remyelination has not been clarified. In this study, we induced the demyelination of the dorsal corticospinal tract (dCST) by a mild contusion spinal cord injury (SCI) on the T10 segment, and manipulated the neuronal activity of the primary motor cortex (M1) using chemogenetic viruses to induce activity and to suppress it. We found that oligodendrocyte precursor cell (OPC) proliferation and oligodendrocyte maturity following remyelination was strengthened after 4-week of neuronal activity stimulation. Furthermore, hindlimb motor function was also found to be improved. Vice versa, suppression of neuronal activity attenuated these effects. These results indicate that bidirectional regulation of neuronal activity can effectively modulate the development of oligodendrocyte lineage cells and the remyelination process. Neuronal activity supports the proliferation of OPCs, improves oligodendrocyte maturation and amplifies the axonal remyelination process, even though leads to better motor function recovery. Manipulation of neuronal activity in a non-invasive manner is therefore a promising avenue for exploration towards the treatment of central nervous system (CNS) demyelination diseases.
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20
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Wilson ER, Della-Flora Nunes G, Weaver MR, Frick LR, Feltri ML. Schwann cell interactions during the development of the peripheral nervous system. Dev Neurobiol 2020; 81:464-489. [PMID: 32281247 DOI: 10.1002/dneu.22744] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/14/2020] [Accepted: 04/06/2020] [Indexed: 12/21/2022]
Abstract
Schwann cells play a critical role in the development of the peripheral nervous system (PNS), establishing important relationships both with the extracellular milieu and other cell types, particularly neurons. In this review, we discuss various Schwann cell interactions integral to the proper establishment, spatial arrangement, and function of the PNS. We include signals that cascade onto Schwann cells from axons and from the extracellular matrix, bidirectional signals that help to establish the axo-glial relationship and how Schwann cells in turn support the axon. Further, we speculate on how Schwann cell interactions with other components of the developing PNS ultimately promote the complete construction of the peripheral nerve.
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Affiliation(s)
- Emma R Wilson
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Gustavo Della-Flora Nunes
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Michael R Weaver
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Luciana R Frick
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - M Laura Feltri
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
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21
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Drenthen GS, Fonseca Wald ELA, Backes WH, Aldenkamp AP, Vermeulen RJ, Debeij-van Hall MHJA, Klinkenberg S, Jansen JFA. Constructing an Axonal-Specific Myelin Developmental Graph and its Application to Childhood Absence Epilepsy. J Neuroimaging 2020; 30:308-314. [PMID: 32255537 PMCID: PMC7317939 DOI: 10.1111/jon.12707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The process of myelination starts in utero around 20 weeks of gestation and continues through adulthood. We first set out to characterize the maturation of the tract-specific myelin content in healthy subjects from childhood (7-12 years) into adulthood (18-32 years). Second, we apply the resulting development graph to children with childhood absence epilepsy (CAE), a pediatric epilepsy that was previously characterized by changes in myelin content. METHODS In a prospective cross-sectional study, 15 healthy children (7-12 years), 14 healthy adult participants (18-32 years) and 17 children with a clinical diagnosis of CAE (6-12 years) were included. For each participant, diffusion weighted images were acquired to reconstruct bundles of white matter tracts and multi-echo multi-slice GRASE images were acquired for myelin-water estimation. Subsequently, a tract-specific myelin development graph was constructed using the percentual difference in myelin-water content from childhood (12 year) to adulthood (25 year). RESULTS The graph revealed myelination patterns, where tracts in the central regions myelinate prior to peripheral tracts and intra-hemispheric tracts as well as tracts in the left hemisphere myelinate prior to inter-hemispheric tracts and tracts in the right hemisphere, respectively. No significant differences were found in myelin-water content between children with CAE and healthy children for neither the early developing tracts, nor the tracts that develop in a later stage. However, the difference between the myelin-water of late and early developing tracts is significantly smaller in the children with CAE. CONCLUSION These results indicate that CAE is associated with widespread neurodevelopmental myelin differences.
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Affiliation(s)
- Gerhard S Drenthen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, De Rondom 70, Eindhoven, The Netherlands
| | - Eric L A Fonseca Wald
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Sterkselseweg 65, Heeze, The Netherlands
| | - Walter H Backes
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands
| | - Albert P Aldenkamp
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, De Rondom 70, Eindhoven, The Netherlands.,Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Sterkselseweg 65, Heeze, The Netherlands
| | - R Jeroen Vermeulen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands
| | | | - Sylvia Klinkenberg
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands
| | - Jacobus F A Jansen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, De Rondom 70, Eindhoven, The Netherlands
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22
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Swire M, Kotelevtsev Y, Webb DJ, Lyons DA, ffrench-Constant C. Endothelin signalling mediates experience-dependent myelination in the CNS. eLife 2019; 8:e49493. [PMID: 31657718 PMCID: PMC6831104 DOI: 10.7554/elife.49493] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/26/2019] [Indexed: 12/22/2022] Open
Abstract
Experience and changes in neuronal activity can alter CNS myelination, but the signalling pathways responsible remain poorly understood. Here we define a pathway in which endothelin, signalling through the G protein-coupled receptor endothelin receptor B and PKC epsilon, regulates the number of myelin sheaths formed by individual oligodendrocytes in mouse and zebrafish. We show that this phenotype is also observed in the prefrontal cortex of mice following social isolation, and is associated with reduced expression of vascular endothelin. Additionally, we show that increasing endothelin signalling rescues this myelination defect caused by social isolation. Together, these results indicate that the vasculature responds to changes in neuronal activity associated with experience by regulating endothelin levels, which in turn affect the myelinating capacity of oligodendrocytes. This pathway may be employed to couple the metabolic support function of myelin to activity-dependent demand and also represents a novel mechanism for adaptive myelination.
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Affiliation(s)
- Matthew Swire
- MRC Centre for Regenerative Medicine, MS Society Edinburgh CentreUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Yuri Kotelevtsev
- Centre for Neurobiology and Brain RestorationSkoltech Institute for Science and TechnologyMoscowRussian Federation
| | - David J Webb
- British Heart Foundation Centre of Research Excellence, Centre of Cardiovascular Science, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUnited Kingdom
| | - David A Lyons
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Charles ffrench-Constant
- MRC Centre for Regenerative Medicine, MS Society Edinburgh CentreUniversity of EdinburghEdinburghUnited Kingdom
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23
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Song X, Wang H, Chen Y, Lai YC. Emergence of an optimal temperature in action-potential propagation through myelinated axons. Phys Rev E 2019; 100:032416. [PMID: 31639929 DOI: 10.1103/physreve.100.032416] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 06/10/2023]
Abstract
In biological organisms, an optimal temperature exists at which the system functioning is maximized or is most effective. To obtain a general and quantitative understanding of the emergence of the optimal temperature is a challenging task. We aim to gain insights into this significant problem in biological physics by addressing the problem of propagation of action potential in myelinated axons. In particular, we construct a Hodgkin-Huxley type of cortical, compartmental model to describe the nodes of Ranvier with coupling between a pair of neighboring compartments characterized by internodal conductance and investigate the effect of temperature on the propagation of the action potential. We conduct direct numerical simulations and develop a physical analysis by taking advantage of the spatially continuous approximation. We find that increasing the temperature requires a larger value of the critical internodal conductance for successful propagation. The striking finding is the spontaneous emergence of an optimal temperature in the sense that, for the propagation of a single action potential at a fixed value of the internodal conductance, the minimum average passage time for one node of Ranvier occurs at this temperature value. A remarkable phenomenon is that the value of the optimal temperature is similar to those of living biological systems observed in experiments.
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Affiliation(s)
- Xinlin Song
- Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China
- School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
| | - Hengtong Wang
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China
| | - Yong Chen
- Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China
- School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
| | - Ying-Cheng Lai
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA
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24
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Galloway DA, Gowing E, Setayeshgar S, Kothary R. Inhibitory milieu at the multiple sclerosis lesion site and the challenges for remyelination. Glia 2019; 68:859-877. [PMID: 31441132 DOI: 10.1002/glia.23711] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/26/2019] [Accepted: 07/26/2019] [Indexed: 12/14/2022]
Abstract
Regeneration of myelin, following injury, can occur within the central nervous system to reinstate proper axonal conductance and provide trophic support. Failure to do so renders the axons vulnerable, leading to eventual degeneration, and neuronal loss. Thus, it is essential to understand the mechanisms by which remyelination or failure to remyelinate occur, particularly in the context of demyelinating and neurodegenerative disorders. In multiple sclerosis, oligodendrocyte progenitor cells (OPCs) migrate to lesion sites to repair myelin. However, during disease progression, the ability of OPCs to participate in remyelination diminishes coincident with worsening of the symptoms. Remyelination is affected by a broad range of cues from intrinsic programming of OPCs and extrinsic local factors to the immune system and other systemic elements including diet and exercise. Here we review the literature on these diverse inhibitory factors and the challenges they pose to remyelination. Results spanning several disciplines from fundamental preclinical studies to knowledge gained in the clinic will be discussed.
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Affiliation(s)
- Dylan A Galloway
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Elizabeth Gowing
- Neurosciences Department, Faculty of Medicine, Centre de recherche du CHUM, Université de Montreal, Montreal, Quebec, Canada
| | - Solmaz Setayeshgar
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Medicine, Department of Biochemistry, Microbiology and Immunology, and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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25
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Abstract
In this issue of Neuron, Spitzer et al. (2019) demonstrate age- and region-dependent diversity in the expression of voltage-gated ion channels and neurotransmitter receptors in oligodendrocyte progenitors. These define their interactions with neurons and thus suggest an increasing functional heterogeneity with age and between brain regions.
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Affiliation(s)
- Jacqueline Trotter
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Germany.
| | - Thomas Mittmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
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26
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Drenthen GS, Fonseca Wald ELA, Backes WH, Debeij-Van Hall MHJA, Hendriksen JGM, Aldenkamp AP, Vermeulen RJ, Klinkenberg S, Jansen JFA. Lower myelin-water content of the frontal lobe in childhood absence epilepsy. Epilepsia 2019; 60:1689-1696. [PMID: 31283841 DOI: 10.1111/epi.16280] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The frontal lobe in childhood absence epilepsy (CAE) might be affected due to the suggested involvement of the frontal lobe during absence seizures and reports on attentional deficits. Previously, subtle white matter abnormalities have been reported in CAE. However, the impact of one of the most characteristic components of the white matter, the myelin content, remains underdetermined. Therefore, this study investigated whether the myelin content in frontal areas is adversely affected in CAE compared to controls. METHODS Seventeen children with childhood absence epilepsy (mean age ± standard deviation [SD], 9.2 ± 2.1 years) and 15 age- and sex-matched controls (mean age ± SD, 9.8 ± 1.8 years) underwent neuropsychological assessment and a magnetic resonance imaging (MRI) examination. T2 relaxometry scans were used to distinguish myelin-water from tissue water and to determine the myelin-water fraction (MWF) in the frontal, temporal, parietal, occipital, and insular lobes. A linear regression model including age and sex as covariates was used to investigate group differences. Furthermore, the relationship of MWF with cognitive performance and epilepsy characteristics was determined. RESULTS The frontal lobe revealed a significantly lower myelin-water content in children with CAE compared to controls over the developmental age range of 6-12 years (5.7 ± 1.0% vs 6.6 ± 1.1%, P = 0.02). This association was not found for any of the other four lobes (P > 0.10). No significant relation was found between myelin-water content and cognitive performance or epilepsy characteristics. SIGNIFICANCE The lower frontal myelin-water content of children with CAE in comparison with healthy controls probably reflects an altered neurodevelopmental aspect in CAE, of which the underlying mechanisms still need to be unraveled.
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Affiliation(s)
- Gerhard S Drenthen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Eric L A Fonseca Wald
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - Walter H Backes
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Jos G M Hendriksen
- Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - Albert P Aldenkamp
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - R Jeroen Vermeulen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Sylvia Klinkenberg
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jacobus F A Jansen
- School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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Habermacher C, Angulo MC, Benamer N. Glutamate versus GABA in neuron-oligodendroglia communication. Glia 2019; 67:2092-2106. [PMID: 30957306 DOI: 10.1002/glia.23618] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 12/20/2022]
Abstract
In the central nervous system (CNS), myelin sheaths around axons are formed by glial cells named oligodendrocytes (OLs). In turn, OLs are generated by oligodendrocyte precursor cells (OPCs) during postnatal development and in adults, according to a process that depends on the proliferation and differentiation of these progenitors. The maturation of OL lineage cells as well as myelination by OLs are complex and highly regulated processes in the CNS. OPCs and OLs express an array of receptors for neurotransmitters, in particular for the two main CNS neurotransmitters glutamate and GABA, and are therefore endowed with the capacity to respond to neuronal activity. Initial studies in cell cultures demonstrated that both glutamate and GABA signaling mechanisms play important roles in OL lineage cell development and function. However, much remains to be learned about the communication of glutamatergic and GABAergic neurons with oligodendroglia in vivo. This review focuses on recent major advances in our understanding of the neuron-oligodendroglia communication mediated by glutamate and GABA in the CNS, and highlights the present controversies in the field. We discuss the expression, activation modes and potential roles of synaptic and extrasynaptic receptors along OL lineage progression. We review the properties of OPC synaptic connectivity with presynaptic glutamatergic and GABAergic neurons in the brain and consider the implication of glutamate and GABA signaling in activity-driven adaptive myelination.
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Affiliation(s)
- Chloé Habermacher
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - María C Angulo
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - Najate Benamer
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
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28
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Ortiz FC, Habermacher C, Graciarena M, Houry PY, Nishiyama A, Oumesmar BN, Angulo MC. Neuronal activity in vivo enhances functional myelin repair. JCI Insight 2019; 5:123434. [PMID: 30896448 PMCID: PMC6538342 DOI: 10.1172/jci.insight.123434] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 03/19/2019] [Indexed: 11/17/2022] Open
Abstract
In demyelinating diseases such as Multiple Sclerosis (MS), demyelination of neuronal fibers impairs impulse conduction and causes axon degeneration. While neuronal activity stimulates oligodendrocyte production and myelination in normal conditions, it remains unclear whether the activity of demyelinated axons restores their loss-of-function in a harmful environment. To investigate this question, we established a model to induce a moderate optogenetic stimulation of demyelinated axons in the corpus callosum at the level of the motor cortex in which cortical circuit activation and locomotor effects were reduced in adult freely moving mice. We demonstrate that a moderate activation of demyelinated axons enhances the differentiation of oligodendrocyte precursor cells onto mature oligodendrocytes, but only under a repeated stimulation paradigm. This activity-dependent increase in the oligodendrocyte pool promotes an extensive remyelination and functional restoration of conduction, as revealed by ultrastructural analyses and compound action potential recordings. Our findings reveal the need of preserving an appropriate neuronal activity in the damaged tissue to promote oligodendrocyte differentiation and remyelination, likely by enhancing axon-oligodendroglia interactions. Our results provide new perspectives for translational research using neuromodulation in demyelinating diseases.
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Affiliation(s)
- Fernando C. Ortiz
- INSERM U1128, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Chloé Habermacher
- INSERM U1128, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, Paris, France
| | - Mariana Graciarena
- Institut du Cerveau et de la Moelle épinière, Sorbonne Université, INSERM U1127, CNRS UMR 7225, Paris, France
| | - Pierre-Yves Houry
- INSERM U1128, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Brahim Nait Oumesmar
- Institut du Cerveau et de la Moelle épinière, Sorbonne Université, INSERM U1127, CNRS UMR 7225, Paris, France
| | - María Cecilia Angulo
- INSERM U1128, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, Paris, France
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29
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Filbin M, Monje M. Developmental origins and emerging therapeutic opportunities for childhood cancer. Nat Med 2019; 25:367-376. [PMID: 30842674 DOI: 10.1038/s41591-019-0383-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 02/01/2019] [Indexed: 02/07/2023]
Abstract
Cancer is the leading disease-related cause of death in children in developed countries. Arising in the context of actively growing tissues, childhood cancers are fundamentally diseases of dysregulated development. Childhood cancers exhibit a lower overall mutational burden than adult cancers, and recent sequencing studies have revealed that the genomic events central to childhood oncogenesis include mutations resulting in broad epigenetic changes or translocations that result in fusion oncoproteins. Here, we will review the developmental origins of childhood cancers, epigenetic dysregulation in tissue stem/precursor cells in numerous examples of childhood cancer oncogenesis and emerging therapeutic opportunities aimed at both cell-intrinsic and microenvironmental targets together with new insights into the mechanisms underlying long-term sequelae of childhood cancer therapy.
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Affiliation(s)
- Mariella Filbin
- Department of Pediatric Oncology, Dana-Farber/Boston Children's Cancer and Blood Disorder Center and Harvard Medical School, Boston, MA, USA
| | - Michelle Monje
- Department of Neurology, Stanford University, Stanford, CA, USA.
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30
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Manipulating Neuronal Activity in the Developing Zebrafish Spinal Cord to Investigate Adaptive Myelination. Methods Mol Biol 2019; 1936:211-225. [PMID: 30820901 DOI: 10.1007/978-1-4939-9072-6_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the central nervous system, oligodendrocyte-lineage cells and myelination can adapt to physiological brain activity. Since myelin can in turn regulate neuronal function, such "adaptive" myelination has been proposed as a form of nervous system plasticity, implicated in learning and cognition. The molecular and cellular mechanisms underlying adaptive myelination and its functional consequences remain to be fully defined, partly because it remains challenging to manipulate activity and monitor myelination over time in vivo at single-cell resolution, in a model that would also allow examination of the functional output of individual neurons and circuits. Here, we describe a workflow to manipulate neuronal activity and to assess oligodendrocyte-lineage cell dynamics and myelination in larval zebrafish, a vertebrate animal model that is ideal for live imaging and amenable to genetic discovery, and that has well-characterized neuronal circuits with myelinated axons.
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31
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Abstract
Neural plasticity in the adult central nervous system involves the adaptation of myelination, including the formation of novel myelin sheaths by adult-born oligodendrocytes. Yet, mature oligodendrocytes slowly but constantly turn over their pre-existing myelin sheaths, thereby establishing an equilibrium of replenishment and degradation that may also be subject to adaptation with consequences for nerve conduction velocity. In this short review we highlight selected approaches to the normal turnover of adult myelin in vivo, from injecting radioactive precursors of myelin constituents in the 1960s to current strategies involving isotope labeling and tamoxifen-induced gene targeting.
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Affiliation(s)
- Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria A Eichel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sophie B Siems
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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32
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Treichel AJ, Hines JH. Development of an Embryonic Zebrafish Oligodendrocyte-Neuron Mixed Coculture System. Zebrafish 2018; 15:586-596. [PMID: 30300571 DOI: 10.1089/zeb.2018.1625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During vertebrate neural development, oligodendrocytes insulate nerve axons with myelin sheaths. Zebrafish (Danio rerio) has emerged as a useful model organism for studying oligodendrocyte development. However, the absence of an in vitro culture system necessitates in vivo manipulations and analyses, which, in some instances, limits the questions that can be addressed. To fill this gap we developed a mixed coculture system for embryonic zebrafish neurons and oligodendrocyte-lineage cells. Cultures harvested from embryos ≥30 hours postfertilization (hpf) yielded oligodendrocyte progenitor cells (OPCs) positive for olig2 and sox10 transgenic reporters. Cultured OPCs exhibited dynamic, exploratory membrane processes, and cell morphologies resembled those established in vivo. Cells harvested from advanced stage embryos possessed more arborized processes than those from early stage embryos. Advanced stage (>60 hpf) embryo culture produced differentiated, mbp+ oligodendrocytes. Genetically tractable neuron subtypes extended neurites when harvested from embryos ≥19 hpf. Coculture produced juxtaposed oligodendrocytes and neurons, demonstrating the practical usefulness of this technique for future studies examining axon-oligodendrocyte interactions under defined conditions. We expect that zebrafish oligodendrocyte culture will complement existing in vivo strengths and may facilitate future studies elucidating the mechanisms of oligodendrocyte specification, proliferation, differentiation, motility, and axon-oligodendrocyte interactions that shape adult myelination patterns.
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Affiliation(s)
| | - Jacob H Hines
- Department of Biology, Winona State University , Winona, Minnesota
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33
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Blades F, Aprico A, Akkermann R, Ellis S, Binder MD, Kilpatrick TJ. The TAM receptor TYRO3 is a critical regulator of myelin thickness in the central nervous system. Glia 2018; 66:2209-2220. [PMID: 30208252 DOI: 10.1002/glia.23481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 02/03/2023]
Abstract
Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system (CNS). Major deficits arise in MS patients due to an inability to repair damaged myelin sheaths following CNS insult, resulting in prolonged axonal exposure and neurodegeneration. The TAM receptors (Tyro3, Axl, and Mertk) have been implicated in MS susceptibility, demyelination and remyelination. Previously, we have shown that Tyro3 regulates developmental myelination and myelin thickness within the optic nerve and rostral region of the corpus callosum (CC) of adult mice. In this study we have verified and extended our previous findings via a comprehensive analysis of axonal ensheathment and myelin thickness in the CC of unchallenged mice, following demyelination and during myelin repair. We show that the loss of the Tyro3 receptor correlates with significantly thinner myelin sheaths in both unchallenged mice and during remyelination, particularly in larger caliber axons. The hypomyelinated phenotype observed in the absence of Tyro3 occurs independently of any influence upon oligodendrocyte precursor cell (OPC) maturation, or density of oligodendrocytes (OLs) or microglia. Rather, the primary effect of Tyro3 is upon the radial expansion of myelin. The loss of Tyro3 leads to a reduction in the number of myelin lamellae on axons, and is therefore most likely a key component of the regulatory mechanism by which oligodendrocytes match myelin production to axonal diameter.
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Affiliation(s)
- Farrah Blades
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Andrea Aprico
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Rainer Akkermann
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sarah Ellis
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Michele D Binder
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trevor J Kilpatrick
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
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34
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Zhao L, Yuan Y, Li P, Pan J, Qin J, Liu Y, Zhang Y, Tian F, Yu B, Zhou S. miR-221-3p Inhibits Schwann Cell Myelination. Neuroscience 2018; 379:239-245. [PMID: 29577996 DOI: 10.1016/j.neuroscience.2018.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 12/14/2022]
Abstract
Following peripheral nerve injury, Schwann Cells (SCs) undergo dedifferentiation, proliferation, migration, and remyelination. Recent works demonstrated the importance of the short non-coding RNA (miRNAs) in SC dedifferentiation and remyelination after nerve injury. Previously, we found some miRNAs like miR-9, miR-221, miR-222 and miR-182 could regulate the proliferation and migration of SCs. Therefore, it is imperative to ask whether these miRNAs could regulate the myelination of SCs. Here we demonstrated that miR-221-3p could inhibit the myelination of SCs when co-cultured with dorsal root ganglion cells in vitro. In addition, NGF1-A binding protein 1 (Nab1) which was essential for SCs myelination could be downregulated by miR-221-3p. Suppressing the expression of Nab1 could reverse the promotion of miR-221-3p antagomir on SC myelination. The effects of miR-221-3p on SC myelination might be used to improve peripheral nerve regeneration, thus offering a new approach to peripheral nerve repair.
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Affiliation(s)
- Lili Zhao
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China; State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, Jiangsu 210000, China
| | - Ying Yuan
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
| | - Ping Li
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Jiacheng Pan
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Jing Qin
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Yisheng Liu
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Yu Zhang
- F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital, Harvard Medical School, 300 Longwood Anevue, Boston, MA 02115, USA
| | - Feng Tian
- F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital, Harvard Medical School, 300 Longwood Anevue, Boston, MA 02115, USA
| | - Bin Yu
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Songlin Zhou
- Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
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35
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Mitew S, Gobius I, Fenlon LR, McDougall SJ, Hawkes D, Xing YL, Bujalka H, Gundlach AL, Richards LJ, Kilpatrick TJ, Merson TD, Emery B. Pharmacogenetic stimulation of neuronal activity increases myelination in an axon-specific manner. Nat Commun 2018; 9:306. [PMID: 29358753 PMCID: PMC5778130 DOI: 10.1038/s41467-017-02719-2] [Citation(s) in RCA: 207] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 12/19/2017] [Indexed: 11/09/2022] Open
Abstract
Mounting evidence suggests that neuronal activity influences myelination, potentially allowing for experience-driven modulation of neural circuitry. The degree to which neuronal activity is capable of regulating myelination at the individual axon level is unclear. Here we demonstrate that stimulation of somatosensory axons in the mouse brain increases proliferation and differentiation of oligodendrocyte progenitor cells (OPCs) within the underlying white matter. Stimulated axons display an increased probability of being myelinated compared to neighboring non-stimulated axons, in addition to being ensheathed with thicker myelin. Conversely, attenuating neuronal firing reduces axonal myelination in a selective activity-dependent manner. Our findings reveal that the process of selecting axons for myelination is strongly influenced by the relative activity of individual axons within a population. These observed cellular changes are consistent with the emerging concept that adaptive myelination is a key mechanism for the fine-tuning of neuronal circuitry in the mammalian CNS.
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Affiliation(s)
- Stanislaw Mitew
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.,Department of Anatomy & Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ilan Gobius
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Laura R Fenlon
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Stuart J McDougall
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
| | - David Hawkes
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Yao Lulu Xing
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Helena Bujalka
- Department of Anatomy & Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia.,Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Linda J Richards
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia.,Schools of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Trevor J Kilpatrick
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.,Melbourne Neuroscience Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Tobias D Merson
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia. .,Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia. .,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Ben Emery
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia. .,Department of Anatomy & Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia. .,Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health and Science University, Portland, OR, 97239, USA.
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37
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Bao BB, Qu DQ, Zhu HY, Gao T, Zheng XY. Brain remodeling after chronic median nerve compression in a rat model. Neural Regen Res 2018; 13:704-708. [PMID: 29722324 PMCID: PMC5950682 DOI: 10.4103/1673-5374.230298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Carpal tunnel syndrome is the most common compressive neuropathy, presenting with sensorimotor dysfunction. In carpal tunnel syndrome patients, irregular afferent signals on functional magnetic resonance imaging are associated with changes in neural plasticity during peripheral nerve injury. However, it is difficult to obtain multi-point neuroimaging data of the brain in the clinic. In the present study, a rat model of median nerve compression was established by median nerve ligation, i.e., carpal tunnel syndrome model. Sensory cortex remodeling was determined by functional magnetic resonance imaging between normal rats and carpal tunnel syndrome models at 2 weeks and 2 months after operation. Stimulation of bilateral paws by electricity for 30 seconds, alternating with 30 seconds of rest period (repeatedly 3 times), resulted in activation of the contralateral sensorimotor cortex in normal rats. When carpal tunnel syndrome rats received this stimulation, the contralateral cerebral hemisphere was markedly activated at 2 weeks after operation, including the primary motor cortex, cerebellum, and thalamus. Moreover, this activation was not visible at 2 months after operation. These findings suggest that significant remodeling of the cerebral cortex appears at 2 weeks and 2 months after median nerve compression.
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Affiliation(s)
- Bing-Bo Bao
- Department of Orthopedic Surgery, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai, China
| | - Dan-Qian Qu
- Yueyang Hospital of Intergrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hong-Yi Zhu
- Department of Orthopedic Surgery, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai, China
| | - Tao Gao
- Department of Orthopedic Surgery, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai, China
| | - Xian-You Zheng
- Department of Orthopedic Surgery, Shanghai Jiao Tong University, Affiliated Sixth People's Hospital, Shanghai, China
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38
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Lopez PH, Báez BB. Gangliosides in Axon Stability and Regeneration. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 156:383-412. [DOI: 10.1016/bs.pmbts.2018.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Myelin is a key evolutionary acquisition that underlay the development of the large, complex nervous systems of all hinged-jaw vertebrates. By promoting rapid, efficient nerve conduction, myelination also made possible the development of the large body size of these vertebrates. In addition to increasing the speed of nerve conduction, myelination has emerged as a source of plasticity in neural circuits that is crucial for proper timing and function. Here, we briefly describe the organization of myelin and of myelinated axons, as well as the functions of myelin in nerve conduction and neural circuits, and consider its potential evolutionary origins.
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Affiliation(s)
- J L Salzer
- New York University School of Medicine, Neuroscience Institute, Departments of Physiology and Neuroscience, NYU School of Medicine, New York, NY 10016, USA.
| | - B Zalc
- Sorbonne Universités, UPMC Paris06, Inserm U1127, CNRS UMR 7225, Institut du cerveau et de la moelle épinière (ICM), GH Pitie-Salpêtrière, 75651 Paris cedex 13, France.
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40
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Matsubara T. Conduction Delay Learning Model for Unsupervised and Supervised Classification of Spatio-Temporal Spike Patterns. Front Comput Neurosci 2017; 11:104. [PMID: 29209191 PMCID: PMC5702355 DOI: 10.3389/fncom.2017.00104] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 11/02/2017] [Indexed: 12/15/2022] Open
Abstract
Precise spike timing is considered to play a fundamental role in communications and signal processing in biological neural networks. Understanding the mechanism of spike timing adjustment would deepen our understanding of biological systems and enable advanced engineering applications such as efficient computational architectures. However, the biological mechanisms that adjust and maintain spike timing remain unclear. Existing algorithms adopt a supervised approach, which adjusts the axonal conduction delay and synaptic efficacy until the spike timings approximate the desired timings. This study proposes a spike timing-dependent learning model that adjusts the axonal conduction delay and synaptic efficacy in both unsupervised and supervised manners. The proposed learning algorithm approximates the Expectation-Maximization algorithm, and classifies the input data encoded into spatio-temporal spike patterns. Even in the supervised classification, the algorithm requires no external spikes indicating the desired spike timings unlike existing algorithms. Furthermore, because the algorithm is consistent with biological models and hypotheses found in existing biological studies, it could capture the mechanism underlying biological delay learning.
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Affiliation(s)
- Takashi Matsubara
- Computational Intelligence, Fundamentals of Computational Science, Department of Computational Science, Graduate School of System Informatics, Kobe University, Hyogo, Japan
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41
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On Myelinated Axon Plasticity and Neuronal Circuit Formation and Function. J Neurosci 2017; 37:10023-10034. [PMID: 29046438 DOI: 10.1523/jneurosci.3185-16.2017] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 08/31/2017] [Indexed: 12/28/2022] Open
Abstract
Studies of activity-driven nervous system plasticity have primarily focused on the gray matter. However, MRI-based imaging studies have shown that white matter, primarily composed of myelinated axons, can also be dynamically regulated by activity of the healthy brain. Myelination in the CNS is an ongoing process that starts around birth and continues throughout life. Myelin in the CNS is generated by oligodendrocytes and recent evidence has shown that many aspects of oligodendrocyte development and myelination can be modulated by extrinsic signals including neuronal activity. Because modulation of myelin can, in turn, affect several aspects of conduction, the concept has emerged that activity-regulated myelination represents an important form of nervous system plasticity. Here we review our increasing understanding of how neuronal activity regulates oligodendrocytes and myelinated axons in vivo, with a focus on the timing of relevant processes. We highlight the observations that neuronal activity can rapidly tune axonal diameter, promote re-entry of oligodendrocyte progenitor cells into the cell cycle, or drive their direct differentiation into oligodendrocytes. We suggest that activity-regulated myelin formation and remodeling that significantly change axonal conduction properties are most likely to occur over timescales of days to weeks. Finally, we propose that precise fine-tuning of conduction along already-myelinated axons may also be mediated by alterations to the axon itself. We conclude that future studies need to analyze activity-driven adaptations to both axons and their myelin sheaths to fully understand how myelinated axon plasticity contributes to neuronal circuit formation and function.
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Gibson EM, Geraghty AC, Monje M. Bad wrap: Myelin and myelin plasticity in health and disease. Dev Neurobiol 2017; 78:123-135. [PMID: 28986960 DOI: 10.1002/dneu.22541] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/31/2017] [Accepted: 10/03/2017] [Indexed: 12/21/2022]
Abstract
Human central nervous system myelin development extends well into the fourth decade of life, and this protracted period underscores the potential for experience to modulate myelination. The concept of myelin plasticity implies adaptability in myelin structure and function in response to experiences during development and beyond. Mounting evidence supports this concept of neuronal activity-regulated changes in myelin-forming cells, including oligodendrocyte precursor cell proliferation, oligodendrogenesis and modulation of myelin microstructure. In healthy individuals, myelin plasticity in associative white matter structures of the brain is implicated in learning and motor function in both rodents and humans. Activity-dependent changes in myelin-forming cells may influence the function of neural networks that depend on the convergence of numerous neural signals on both a temporal and spatial scale. However, dysregulation of myelin plasticity can disadvantageously alter myelin microstructure and result in aberrant circuit function or contribute to pathological cell proliferation. Emerging roles for myelin plasticity in normal neurological function and in disease are discussed. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 123-135, 2018.
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Affiliation(s)
- Erin M Gibson
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Anna C Geraghty
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Michelle Monje
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
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43
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Cole KLH, Early JJ, Lyons DA. Drug discovery for remyelination and treatment of MS. Glia 2017; 65:1565-1589. [PMID: 28618073 DOI: 10.1002/glia.23166] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 12/19/2022]
Abstract
Glia constitute the majority of the cells in our nervous system, yet there are currently no drugs that target glia for the treatment of disease. Given ongoing discoveries of the many roles of glia in numerous diseases of the nervous system, this is likely to change in years to come. Here we focus on the possibility that targeting the oligodendrocyte lineage to promote regeneration of myelin (remyelination) represents a therapeutic strategy for the treatment of the demyelinating disease multiple sclerosis, MS. We discuss how hypothesis driven studies have identified multiple targets and pathways that can be manipulated to promote remyelination in vivo, and how this work has led to the first ever remyelination clinical trials. We also highlight how recent chemical discovery screens have identified a host of small molecule compounds that promote oligodendrocyte differentiation in vitro. Some of these compounds have also been shown to promote myelin regeneration in vivo, with one already being trialled in humans. Promoting oligodendrocyte differentiation and remyelination represents just one potential strategy for the treatment of MS. The pathology of MS is complex, and its complete amelioration may require targeting multiple biological processes in parallel. Therefore, we present an overview of new technologies and models for phenotypic analyses and screening that can be exploited to study complex cell-cell interactions in in vitro and in vivo systems. Such technological platforms will provide insight into fundamental mechanisms and increase capacities for drug-discovery of relevance to glia and currently intractable disorders of the CNS.
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Affiliation(s)
- Katy L H Cole
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - Jason J Early
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - David A Lyons
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
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44
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Klingseisen A, Lyons DA. Axonal Regulation of Central Nervous System Myelination: Structure and Function. Neuroscientist 2017; 24:7-21. [PMID: 28397586 DOI: 10.1177/1073858417703030] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Approximately half of the human brain consists of myelinated axons. Central nervous system (CNS) myelin is made by oligodendrocytes and is essential for nervous system formation, health, and function. Once thought simply as a static insulator that facilitated rapid impulse conduction, myelin is now known to be made and remodeled in to adult life. Oligodendrocytes have a remarkable capacity to differentiate by default, but many aspects of their development can be influenced by axons. However, how axons and oligodendrocytes interact and cooperate to regulate myelination in the CNS remains unclear. Here, we review recent advances in our understanding of how such interactions generate the complexity of myelination known to exist in vivo. We highlight intriguing results that indicate that the cross-sectional size of an axon alone may regulate myelination to a surprising degree. We also review new studies, which have highlighted diversity in the myelination of axons of different neuronal subtypes and circuits, and structure-function relationships, which suggest that myelinated axons can be exquisitely fine-tuned to mediate precise conduction needs. We also discuss recent advances in our understanding of how neuronal activity regulates CNS myelination, and aim to provide an integrated overview of how axon-oligodendrocyte interactions sculpt neuronal circuit structure and function.
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Affiliation(s)
- Anna Klingseisen
- 1 Centre for Neuroregeneration, University of Edinburgh, Edinburgh, UK
| | - David A Lyons
- 1 Centre for Neuroregeneration, University of Edinburgh, Edinburgh, UK
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Maeda Y, Kim H, Kettner N, Kim J, Cina S, Malatesta C, Gerber J, McManus C, Ong-Sutherland R, Mezzacappa P, Libby A, Mawla I, Morse LR, Kaptchuk TJ, Audette J, Napadow V. Rewiring the primary somatosensory cortex in carpal tunnel syndrome with acupuncture. Brain 2017; 140:914-927. [PMID: 28334999 PMCID: PMC5837382 DOI: 10.1093/brain/awx015] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 12/08/2016] [Accepted: 12/17/2016] [Indexed: 12/31/2022] Open
Abstract
Carpal tunnel syndrome is the most common entrapment neuropathy, affecting the median nerve at the wrist. Acupuncture is a minimally-invasive and conservative therapeutic option, and while rooted in a complex practice ritual, acupuncture overlaps significantly with many conventional peripherally-focused neuromodulatory therapies. However, the neurophysiological mechanisms by which acupuncture impacts accepted subjective/psychological and objective/physiological outcomes are not well understood. Eligible patients (n = 80, 65 female, age: 49.3 ± 8.6 years) were enrolled and randomized into three intervention arms: (i) verum electro-acupuncture 'local' to the more affected hand; (ii) verum electro-acupuncture at 'distal' body sites, near the ankle contralesional to the more affected hand; and (iii) local sham electro-acupuncture using non-penetrating placebo needles. Acupuncture therapy was provided for 16 sessions over 8 weeks. Boston Carpal Tunnel Syndrome Questionnaire assessed pain and paraesthesia symptoms at baseline, following therapy and at 3-month follow-up. Nerve conduction studies assessing median nerve sensory latency and brain imaging data were acquired at baseline and following therapy. Functional magnetic resonance imaging assessed somatotopy in the primary somatosensory cortex using vibrotactile stimulation over three digits (2, 3 and 5). While all three acupuncture interventions reduced symptom severity, verum (local and distal) acupuncture was superior to sham in producing improvements in neurophysiological outcomes, both local to the wrist (i.e. median sensory nerve conduction latency) and in the brain (i.e. digit 2/3 cortical separation distance). Moreover, greater improvement in second/third interdigit cortical separation distance following verum acupuncture predicted sustained improvements in symptom severity at 3-month follow-up. We further explored potential differential mechanisms of local versus distal acupuncture using diffusion tensor imaging of white matter microstructure adjacent to the primary somatosensory cortex. Compared to healthy adults (n = 34, 28 female, 49.7 ± 9.9 years old), patients with carpal tunnel syndrome demonstrated increased fractional anisotropy in several regions and, for these regions we found that improvement in median nerve latency was associated with reduction of fractional anisotropy near (i) contralesional hand area following verum, but not sham, acupuncture; (ii) ipsilesional hand area following local, but not distal or sham, acupuncture; and (iii) ipsilesional leg area following distal, but not local or sham, acupuncture. As these primary somatosensory cortex subregions are distinctly targeted by local versus distal acupuncture electrostimulation, acupuncture at local versus distal sites may improve median nerve function at the wrist by somatotopically distinct neuroplasticity in the primary somatosensory cortex following therapy. Our study further suggests that improvements in primary somatosensory cortex somatotopy can predict long-term clinical outcomes for carpal tunnel syndrome.
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Affiliation(s)
- Yumi Maeda
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Department of Radiology, Logan University, Chesterfield, MO, 63017, USA
| | - Hyungjun Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Clinical Research Division, Korean Institute of Oriental Medicine, Daejeon, 34054, South Korea
| | - Norman Kettner
- Department of Radiology, Logan University, Chesterfield, MO, 63017, USA
| | - Jieun Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Clinical Research Division, Korean Institute of Oriental Medicine, Daejeon, 34054, South Korea
| | - Stephen Cina
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - Cristina Malatesta
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Medford, MA, 02155, USA
| | - Jessica Gerber
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - Claire McManus
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Medford, MA, 02155, USA
| | - Rebecca Ong-Sutherland
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Medford, MA, 02155, USA
| | - Pia Mezzacappa
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - Alexandra Libby
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - Ishtiaq Mawla
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
| | - Leslie R. Morse
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, 02114, USA
| | - Ted J. Kaptchuk
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Joseph Audette
- Department of Pain Medicine, Harvard Vanguard Medical Associates, Atrium Health, Boston, MA, 02215, USA
| | - Vitaly Napadow
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Department of Radiology, Logan University, Chesterfield, MO, 63017, USA
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46
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Mogha A, D'Rozario M, Monk KR. G Protein-Coupled Receptors in Myelinating Glia. Trends Pharmacol Sci 2016; 37:977-987. [PMID: 27670389 DOI: 10.1016/j.tips.2016.09.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 09/02/2016] [Accepted: 09/06/2016] [Indexed: 12/21/2022]
Abstract
The G protein-coupled receptor (GPCR) superfamily represents the largest class of functionally selective drug targets for disease modulation and therapy. GPCRs have been studied in great detail in central nervous system (CNS) neurons, but these important molecules have been relatively understudied in glia. In recent years, however, exciting new roles for GPCRs in glial cell biology have emerged. We focus here on the key roles of GPCRs in a specialized subset of glia, myelinating glia. We highlight recent work firmly establishing GPCRs as regulators of myelinating glial cell development and myelin repair. These advances expand our understanding of myelinating glial cell biology and underscore the utility of targeting GPCRs to promote myelin repair in human disease.
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Affiliation(s)
- Amit Mogha
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mitchell D'Rozario
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kelly R Monk
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA; Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Wilmes KA, Schleimer JH, Schreiber S. Spike-timing dependent inhibitory plasticity to learn a selective gating of backpropagating action potentials. Eur J Neurosci 2016; 45:1032-1043. [DOI: 10.1111/ejn.13326] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/07/2016] [Accepted: 06/27/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Katharina Anna Wilmes
- Institute for Theoretical Biology; Department of Biology; Humboldt-Universität zu Berlin; Philippstr. 13 10115 Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
| | - Jan-Hendrik Schleimer
- Institute for Theoretical Biology; Department of Biology; Humboldt-Universität zu Berlin; Philippstr. 13 10115 Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology; Department of Biology; Humboldt-Universität zu Berlin; Philippstr. 13 10115 Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
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48
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Glu-tubulin is a marker for Schwann cells and can distinguish between schwannomas and neurofibromas. Histochem Cell Biol 2016; 146:467-77. [PMID: 27278446 DOI: 10.1007/s00418-016-1455-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
Schwann cells generate myelin sheaths around the axons of the peripheral nervous system, thus facilitating efficient nerve impulse propagation. Two main tumor types can arise from peripheral nerves, schwannomas and neurofibromas, which are sometimes difficult to distinguish and may require the use of diagnostic biomarkers. Here, we characterize a new marker for Schwann cells and its potential use as a diagnostic marker for schwannomas. Immunohistochemistry for Glu-tubulin, a posttranslational modification of α-tubulin, was performed in mouse and human tissues. This technique labels Schwann cells but not oligodendrocytes. All peripheral nerves were immunoreactive for this antibody, including large nerve trunks, thin myelinated nerves, as well as the myenteric and submucous plexus of the digestive tract. In the mouse brain, many neurons were immunoreactive for Glu-tubulin but oligodendrocytes were negative. During embryo development, immunoreactive nerves were already found at E10. In Schwann cells, the staining is restricted to the myelin sheaths and is not present in the perinuclear cytoplasm or the Ranvier nodes. Primary cultures of fibroblasts and Schwann cells were established from mouse sciatic nerves, and Western blot analysis showed that Glu-tubulin immunoreactivity was found in the Schwann cells but not in the fibroblasts. Clinical specimens of schwannomas (n = 20) and neurofibromas (n = 20) were stained with anti-Glu-tubulin antibodies. Schwannomas presented a strong staining in all tumor cells, whereas neurofibromas had a light speckled staining pattern, easily distinguishable from the one found in schwannomas. In conclusion, Glu-tubulin can be used as a marker of Schwann cells and can help in diagnosing peripheral nerve tumors.
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49
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Thakurela S, Garding A, Jung RB, Müller C, Goebbels S, White R, Werner HB, Tiwari VK. The transcriptome of mouse central nervous system myelin. Sci Rep 2016; 6:25828. [PMID: 27173133 PMCID: PMC4865983 DOI: 10.1038/srep25828] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/21/2016] [Indexed: 01/03/2023] Open
Abstract
Rapid nerve conduction in the CNS is facilitated by insulation of axons with myelin, a specialized oligodendroglial compartment distant from the cell body. Myelin is turned over and adapted throughout life; however, the molecular and cellular basis of myelin dynamics remains elusive. Here we performed a comprehensive transcriptome analysis (RNA-seq) of myelin biochemically purified from mouse brains at various ages and find a surprisingly large pool of transcripts enriched in myelin. Further computational analysis showed that the myelin transcriptome is closely related to the myelin proteome but clearly distinct from the transcriptomes of oligodendrocytes and brain tissues, suggesting a highly selective incorporation of mRNAs into the myelin compartment. The mRNA-pool in myelin displays maturation-dependent dynamic changes of composition, abundance, and functional associations; however ageing-dependent changes after 6 months were minor. We suggest that this transcript pool enables myelin turnover and the local adaptation of individual pre-existing myelin sheaths.
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Affiliation(s)
| | - Angela Garding
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Ramona B. Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Christina Müller
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University, 55128 Mainz, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Robin White
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University, 55128 Mainz, Germany
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
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