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Platelet-rich plasma loaded nerve guidance conduit as implantable biocompatible materials for recurrent laryngeal nerve regeneration. NPJ Regen Med 2022; 7:49. [PMID: 36104458 PMCID: PMC9474804 DOI: 10.1038/s41536-022-00239-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 08/05/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractVocal cord paralysis caused by recurrent laryngeal nerve (RLN) injury during thyroidectomy results in hoarseness, aspiration, and dyspnea. We evaluated the usefulness of nerve guidance conduits (NGCs) constructed from an asymmetric polycaprolactone (PCL)/Pluronic F127 porous membrane and filled with platelet-rich plasma (PRP) for functional RLN regeneration. We evaluated the proliferation and migration of Schwann cells (SCs) after PRP treatment in vitro. For the in vivo study, rabbits were divided into a non-loaded NGC group and a PRP-loaded NGC group. The left RLNs were resected and interposed with the NGCs. Functional and histological examinations of the vocal cords were performed. SC proliferation and migration increased in a PRP dose-dependent manner, with the PRP increasing the levels of neurotrophic factors, myelin-associated glycoprotein, and ERK. In vivo, the PRP group showed significantly better vocal cord mobility and less vocalis muscle atrophy than the non-loaded NGC group. Histologically, the ingrowth of nerve endings occurred more rapidly in the PRP group, and acetylcholinesterase, neurofilament, and S-100 expression in neural endings were significantly higher in the PRP group. Furthermore, transmission electron microscopy showed that myelinated axons were more tightly packed in the PRP group. This study shows that PRP-loaded NGCs provide a favorable environment for neural regeneration and suggests that this technique has therapeutic potential for promoting RLN recovery.
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Li T, Niu J, Yu G, Ezan P, Yi C, Wang X, Koulakoff A, Gao X, Chen X, Sáez JC, Giaume C, Xiao L. Connexin 43 deletion in astrocytes promotes CNS remyelination by modulating local inflammation. Glia 2019; 68:1201-1212. [PMID: 31868275 DOI: 10.1002/glia.23770] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 11/30/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
Abstract
As the most abundant gap junction protein in the central nervous system (CNS), astrocytic connexin 43 (Cx43) maintains astrocyte network homeostasis, affects oligodendroglial development and participates in CNS pathologies as well as injury progression. However, its role in remyelination is not yet fully understood. To address this issue, we used astrocyte-specific Cx43 conditional knockout (Cx43 cKO) mice generated through the use of a hGFAP-cre promoter, in combination with mice carrying a floxed Cx43 allele that were subjected to lysolecithin so as to induce demyelination. We found no significant difference in the demyelination of the corpus callosum between Cx43 cKO mice and their non-cre littermate controls, while the remyelination process in Cx43 cKO mice was accelerated. Moreover, an increased number of mature oligodendrocytes and an unaltered number of oligodendroglial lineage cells were found in Cx43 cKO mouse lesions. This indicates that oligodendrocyte precursor cell (OPC) differentiation was facilitated by astroglial Cx43 depletion as remyelination progressed. Underlying the latter, there was a down-regulated glial activation and modulated local inflammation as well as a reduction of myelin debris in Cx43 cKO mice. Importantly, 2 weeks of orally administrating boldine, a natural alkaloid that blocks Cx hemichannel activity in astrocytes without affecting gap junctional communication, obviously modulated local inflammation and promoted remyelination. Together, the data suggest that the astrocytic Cx43 hemichannel is negatively involved in the remyelination process by favoring local inflammation. Consequently, inhibiting Cx43 hemichannel functionality may be a potential therapeutic approach for demyelinating diseases in the CNS.
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Affiliation(s)
- Tao Li
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jianqin Niu
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Guangdan Yu
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Chenju Yi
- Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Xiaorui Wang
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Annette Koulakoff
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Xing Gao
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xianjun Chen
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Lan Xiao
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
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GDNF pretreatment overcomes Schwann cell phenotype mismatch to promote motor axon regeneration via sensory graft. Exp Neurol 2019; 318:258-266. [PMID: 31100319 DOI: 10.1016/j.expneurol.2019.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/10/2019] [Accepted: 05/12/2019] [Indexed: 12/11/2022]
Abstract
In the clinic, severe motor nerve injury is commonly repaired by autologous sensory nerve bridging, but the ability of Schwann cells (SCs) in sensory nerves to support motor neuron axon growth is poor due to phenotype mismatch. In vitro experiments have demonstrated that sensory-derived SCs overcome phenotypic mismatch-induced growth inhibition after pretreatment with exogenous glial cell-derived neurotrophic factor (GDNF) and induce motor neuron axonal growth. Thus, we introduced a novel staging surgery: In the first stage of surgery, the denervated sensory nerve was pretreated with sustained-release GDNF, which was encapsulated into a self-assembling peptide nanofiber scaffold (SAPNS) RADA-16I in the donor area in vivo. In the second stage of surgery, the pretreated sensory grafts were transplanted to repair motor nerve injury. Motor axon regeneration and remyelination and muscle functional recovery after the second surgery was compared to those in the control groups. The expression of genes previously shown to be differently expressed in motor and sensory SCs was also analyzed in pretreated sensory grafts by qRT-PCR to explore possible changes after exogenous GDNF application. Exogenous GDNF acted directly on the denervated sensory nerve graft in vivo, increasing the expression of endogenous GDNF and sensory SC-derived marker brain-derived neurotrophic factor (BDNF). After transplantation to repair motor nerve injury, exogenous GDNF pretreatment promoted the regeneration and remyelination of proximal motor axons and the recovery of muscle function. Further research into how phenotype, gene expression and changes in neurotrophic factors in SCs are affected by GDNF will help us design more effective methods to treat peripheral nerve injury.
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Holm M, Morken TS, Fichorova RN, VanderVeen DK, Allred EN, Dammann O, Leviton A. Systemic Inflammation-Associated Proteins and Retinopathy of Prematurity in Infants Born Before the 28th Week of Gestation. Invest Ophthalmol Vis Sci 2017; 58:6419-6428. [PMID: 29260199 PMCID: PMC5736326 DOI: 10.1167/iovs.17-21931] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose To assess the association between systemic levels of inflammation-associated proteins and severe retinopathy of prematurity (ROP) in extremely preterm infants. Methods We collected whole blood on filter paper on postnatal days 1, 7, 14, 21, and 28 from 1205 infants born before the 28th week of gestation, and measured the concentrations of 27 inflammation-associated, angiogenic, and neurotrophic proteins. We calculated odds ratios with 95% confidence intervals for the association between top quartile concentrations of each protein and prethreshold ROP. Results During the first three weeks after birth, high concentrations of VEGF-R1, myeloperoxidase (MPO), IL-8, intercellular adhesion molecule (ICAM)-1, matrix metalloproteinase 9, erythropoietin, TNF-α, and basic fibroblast growth factor were associated with an increased risk for prethreshold ROP. On day 28, high levels of serum amyloid A, MPO, IL-6, TNF-α, TNF-R1/-R2, IL-8, and ICAM-1 were associated with an increased risk. Top quartile concentrations of the proinflammatory cytokines TNF-α and IL-6 were associated with increased risks of ROP when levels of neuroprotective proteins and growth factors, including BDNF, insulin-like growth factor 1, IGFBP-1, VEGFR-1 and -2, ANG-1 and PlGF, were not in the top quartile. In contrast, high concentrations of NT-4 and BDNF appeared protective only in infants without elevated inflammatory mediators. Conclusions Systemic inflammation during the first postnatal month was associated with an increased risk of prethreshold ROP. Elevated concentrations of growth factors, angiogenic proteins, and neurotrophins appeared to modulate this risk, and were capable of reducing the risk even in the absence of systemic inflammation.
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Affiliation(s)
- Mari Holm
- Department of Clinical and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Pediatrics, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Tora S Morken
- Department of Neuromedicine and Movement Science (INB), Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Ophthalmology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Raina N Fichorova
- Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Deborah K VanderVeen
- Department of Ophthalmology, Children's Hospital Boston, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Harvard University, Boston, Massachusetts, United States
| | - Elizabeth N Allred
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Harvard University, Boston, Massachusetts, United States
| | - Olaf Dammann
- Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, Massachusetts, United States.,Perinatal Epidemiology Unit, Department of Gynecology and Obstetrics, Hannover Medical School, Hannover, Germany
| | - Alan Leviton
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Harvard University, Boston, Massachusetts, United States
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5
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Mandara MT, Reginato A, Balducci F, Bernardini M. A leukomyeloencephalopathy of unknown origin in an Azawakh dog. Res Vet Sci 2017; 113:101-104. [PMID: 28926781 DOI: 10.1016/j.rvsc.2017.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/04/2017] [Accepted: 09/03/2017] [Indexed: 11/29/2022]
Abstract
A diffuse bilaterally symmetrical leukomyeloencephalopathy was observed in a 6-year-old male Azawakh dog showing a slowly progressive ataxia of six months duration associated with sensory disorders. Severe bilaterally symmetrical demyelination and vacuolisation were confined to the dorsal columns along the entire spinal cord with a minor axonal degeneration. The main changes of myelin sheaths consisted in splitting and intramyelin vacuolization. Naked axons were scattered in a network of astrocytic processes and collagen fibres. Few reactive macrophages exhibiting a foamy pattern were observed adjacent to the small vessels. In the brain, cuneatus nuclei showed a number of atrophic neurons. A spongy change was observed in the raphe nuclei, spinal tract and nuclei of trigeminal nerve, and caudal cerebellar peduncles. Lesions there were neither in the spinal and trigeminal nerves, nor in the spinal ganglia. Although in the absence of a pedigree analysis support an inherited cause cannot be completely excluded.
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Affiliation(s)
- Maria Teresa Mandara
- Department of Veterinary Medicine, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy.
| | - Alice Reginato
- Department of Veterinary Medicine, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy
| | - Federica Balducci
- Veterinary Hospital "I Portoni Rossi", Via Roma 57/A, 40069 Zola Predosa, BO, Italy.
| | - Marco Bernardini
- Veterinary Hospital "I Portoni Rossi", Via Roma 57/A, 40069 Zola Predosa, BO, Italy; Department of Animal Medicine, Production and Health, University of Padova, Viale dell'Università 16, 35020 Legnaro, PD, Italy.
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6
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Goldstein EZ, Church JS, Hesp ZC, Popovich PG, McTigue DM. A silver lining of neuroinflammation: Beneficial effects on myelination. Exp Neurol 2016; 283:550-9. [PMID: 27151600 DOI: 10.1016/j.expneurol.2016.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/27/2016] [Accepted: 05/01/2016] [Indexed: 12/19/2022]
Abstract
Myelin accelerates action potential conduction velocity and provides essential energy support for axons. Unfortunately, myelin and myelinating cells are often vulnerable to injury or disease, resulting in myelin damage, which in turn can lead to axon dysfunction, overt pathology and neurological impairment. Inflammation is a common component of trauma and disease in both the CNS and PNS and therefore an active inflammatory response is often considered deleterious to myelin health. While inflammation can certainly damage myelin, inflammatory processes also can positively affect oligodendrocyte lineage progression, myelin debris clearance, oligodendrocyte metabolism and myelin repair. In the periphery, inflammatory cascades can also augment myelin repair, including processes initiated by infiltrating immune cells as well as by local Schwann cells. In this review, various aspects of inflammation beneficial to myelin repair are discussed and should be considered when designing or implementing anti-inflammatory therapies for CNS and PNS injury involving myelinating cells.
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Affiliation(s)
- Evan Z Goldstein
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Jamie S Church
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Zoe C Hesp
- Neuroscience Graduate Program, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Phillip G Popovich
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States
| | - Dana M McTigue
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, United States; Center for Brain and Spinal Cord Repair, Wexner Medical Center, The Ohio State University, United States.
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7
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Binzer S, Stenager E, Binzer M, Kyvik KO, Hillert J, Imrell K. Genetic analysis of the isolated Faroe Islands reveals SORCS3 as a potential multiple sclerosis risk gene. Mult Scler 2015; 22:733-40. [DOI: 10.1177/1352458515602338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/21/2015] [Indexed: 11/15/2022]
Abstract
Background: In search of the missing heritability in multiple sclerosis (MS), additional approaches adding to the genetic discoveries of large genome-wide association studies are warranted. Objective: The objective of this research paper is to search for rare genetic MS risk variants in the genetically homogenous population of the isolated Faroe Islands. Methods: Twenty-nine Faroese MS cases and 28 controls were genotyped with the HumanOmniExpressExome-chip. The individuals make up 1596 pair-combinations in which we searched for identical-by-descent shared segments using the PLINK-program. Results: A segment spanning 63 SNPs with excess case-case-pair sharing was identified (0.00173 < p > 0.00212). A haplotype consisting of 42 of the 63 identified SNPs which spanned the entire the Sortilin-related vacuolar protein sorting 10 domain containing receptor 3 ( SORCS3) gene had a carrier frequency of 0.34 in cases but was not present in any controls ( p = 0.0008). Conclusion: This study revealed an oversharing in case-case-pairs of a segment spanning 63 SNPs and the entire SORCS3. While not previously associated with MS, SORCS3 appears to be important in neuronal plasticity through its binding of neurotrophin factors and involvement in glutamate homeostasis. Although additional work is needed to scrutinise the genetic effect of the SORCS3-covering haplotype, this study suggests that SORCS3 may also be important in MS pathogenesis.
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Affiliation(s)
- S Binzer
- Institute of Regional Health Research, University of Southern Denmark, Denmark/Hospital of Southern Jutland, Denmark/Odense Patient data Explorative Network (OPEN), University of Southern Denmark, Denmark/ Torshavn National Hospital, Faroe Islands
| | - E Stenager
- Institute of Regional Health Research, University of Southern Denmark, Denmark/Hospital of Southern Jutland, Denmark/ MS Clinic of Southern Jutland (Sønderborg, Esbjerg, Vejle), Department of Neurology, Denmark
| | - M Binzer
- Institute of Regional Health Research, University of Southern Denmark, Denmark
| | - KO Kyvik
- Department of Clinical Research, University of Southern Denmark, Denmark/Odense Patient data Explorative Network (OPEN), University of Southern Denmark, Denmark
| | - J Hillert
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - K Imrell
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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8
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Monk KR, Feltri ML, Taveggia C. New insights on Schwann cell development. Glia 2015; 63:1376-93. [PMID: 25921593 PMCID: PMC4470834 DOI: 10.1002/glia.22852] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/13/2015] [Indexed: 12/11/2022]
Abstract
In the peripheral nervous system, Schwann cells are glial cells that are in intimate contact with axons throughout development. Schwann cells generate the insulating myelin sheath and provide vital trophic support to the neurons that they ensheathe. Schwann cell precursors arise from neural crest progenitor cells, and a highly ordered developmental sequence controls the progression of these cells to become mature myelinating or nonmyelinating Schwann cells. Here, we discuss both seminal discoveries and recent advances in our understanding of the molecular mechanisms that drive Schwann cell development and myelination with a focus on cell-cell and cell-matrix signaling events.
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Affiliation(s)
- Kelly R Monk
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri
| | - M Laura Feltri
- Department of Biochemistry and Neurology, Hunter James Kelly Research Institute, University at Buffalo, State University of New York, Buffalo, New York
| | - Carla Taveggia
- Division of Neuroscience and INSPE, San Raffaele Scientific Institute, Milan, Italy
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9
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Tanaka T, Yoshida S. Mechanisms of remyelination: recent insight from experimental models. Biomol Concepts 2015; 5:289-98. [PMID: 25372760 DOI: 10.1515/bmc-2014-0015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/15/2014] [Indexed: 11/15/2022] Open
Abstract
Oligodendrocytes and myelin play essential roles in the vertebrate central nervous system. Demyelination disrupts saltatory nerve conduction, leading to axonal degeneration and neurological disabilities. Remyelination is a regenerative process that replaces lost myelin. However, remyelination is disrupted in demyelinating diseases such as multiple sclerosis, at least partially, due to the failure of oligodendrocyte precursor cells to differentiate into myelinating oligodendrocytes. Understanding the molecular and cellular mechanisms that impact the differentiation of oligodendrocytes and myelination may help in the development of novel therapeutic strategies for demyelinating diseases. In this review, we focus on the molecular mechanisms controlling the differentiation of oligodendrocytes during remyelination, and we discuss the function of astrocytes and microglia in animal models of demyelinating diseases.
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10
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Scalabrino G, Veber D, De Giuseppe R, Roncaroli F. Low levels of cobalamin, epidermal growth factor, and normal prions in multiple sclerosis spinal cord. Neuroscience 2015; 298:293-301. [PMID: 25888933 DOI: 10.1016/j.neuroscience.2015.04.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 04/08/2015] [Accepted: 04/10/2015] [Indexed: 11/16/2022]
Abstract
We have previously demonstrated that multiple sclerosis (MS) patients have abnormal cerebrospinal fluid (CSF) levels of the key myelin-related molecules cobalamin (Cbl), epidermal growth factor (EGF), and normal cellular prions (PrP(C)s), thus confirming that some CSF abnormalities may be co-responsible for remyelination failure. We determined the levels of these three molecules in post-mortem spinal cord (SC) samples taken from MS patients and control patients. The control SC samples, almost all of which came from non-neurological patients, did not show any microscopic lesions of any type. All of the samples were supplied by the U.K. MS Tissue Bank. The Cbl, EGF, and PrP(C) levels were determined using enzyme-linked immunosorbent assays. The SC total homocysteine level was determined using a competitive immunoenzymatic assay. CSF samples, taken from a further group of MS patients, were used for the assay of holo-transcobalamin (holo-TC) levels. The Cbl, EGF, and PrP(C) levels were significantly decreased in MS SCs in comparison with controls and, paradoxically, the decreased Cbl levels were associated with decreased SC levels of homocysteine, a biochemical marker of Cbl deficiency. The trends of EGF and PrP(C) levels paralleled those previously found in CSF, whereas that of Cbl was the opposite. There was no significant difference in CSF holo-TC levels between the MS patients and the controls. Given that we have previously demonstrated that Cbl positively regulates central nervous system EGF levels, it is conceivable that the low EGF levels in the MS SC may be causally related to a local decrease in Cbl levels. Only PrP(C) levels were invariably decreased in both the SC and CSF regardless of the clinical course of the disease. These findings suggest that the simultaneous lack of Cbl, EGF, and PrP(C)s may greatly hamper the remyelination process in MS patients, because they are key molecules of the machinery for remyelination.
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Affiliation(s)
- G Scalabrino
- Department of Biomedical Sciences, Laboratory of Neuropathology, University of Milan, 20133 Milan, Italy.
| | - D Veber
- Department of Biomedical Sciences, Laboratory of Neuropathology, University of Milan, 20133 Milan, Italy
| | - R De Giuseppe
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20122 Milan, Italy
| | - F Roncaroli
- Division of Brain Sciences, Imperial College, London W12 0NN, UK
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11
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Faroni A, Castelnovo LF, Procacci P, Caffino L, Fumagalli F, Melfi S, Gambarotta G, Bettler B, Wrabetz L, Magnaghi V. Deletion of GABA-B receptor in Schwann cells regulates remak bundles and small nociceptive C-fibers. Glia 2014; 62:548-65. [PMID: 24474699 DOI: 10.1002/glia.22625] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 12/16/2023]
Abstract
The mechanisms regulating the differentiation into non-myelinating Schwann cells is not completely understood. Recent evidence indicates that GABA-B receptors may regulate myelination and nociception in the peripheral nervous system. GABA-B receptor total knock-out mice exhibit morphological and molecular changes in peripheral myelin. The number of small myelinated fibers is higher and associated with altered pain sensitivity. Herein, we analyzed whether these changes may be produced by a specific deletion of GABA-B receptors in Schwann cells. The conditional mice (P0-GABA-B1(fl/fl)) show a morphological phenotype characterized by a peculiar increase in the number of small unmyelinated fibers and Remak bundles, including nociceptive C-fibers. The P0-GABA-B1(fl/fl) mice are hyperalgesic and allodynic. In these mice, the morphological and behavioral changes are associated with a downregulation of neuregulin 1 expression in nerves. Our findings suggest that the altered pain sensitivity derives from a Schwann cell-specific loss of GABA-B receptor functions, pointing to a role for GABA-B receptors in the regulation of Schwann cell maturation towards the non-myelinating phenotype.
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Affiliation(s)
- Alessandro Faroni
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Via Balzaretti 9, 20133, Milan, Italy; Blond McIndoe Laboratories, The University of Manchester, Institute of Inflammation and Repair, M13 9PT, Manchester, United Kingdom
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12
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Beirowski B. Concepts for regulation of axon integrity by enwrapping glia. Front Cell Neurosci 2013; 7:256. [PMID: 24391540 PMCID: PMC3867696 DOI: 10.3389/fncel.2013.00256] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Long axons and their enwrapping glia (EG; Schwann cells (SCs) and oligodendrocytes (OLGs)) form a unique compound structure that serves as conduit for transport of electric and chemical information in the nervous system. The peculiar cytoarchitecture over an enormous length as well as its substantial energetic requirements make this conduit particularly susceptible to detrimental alterations. Degeneration of long axons independent of neuronal cell bodies is observed comparatively early in a range of neurodegenerative conditions as a consequence of abnormalities in SCs and OLGs . This leads to the most relevant disease symptoms and highlights the critical role that these glia have for axon integrity, but the underlying mechanisms remain elusive. The quest to understand why and how axons degenerate is now a crucial frontier in disease-oriented research. This challenge is most likely to lead to significant progress if the inextricable link between axons and their flanking glia in pathological situations is recognized. In this review I compile recent advances in our understanding of the molecular programs governing axon degeneration, and mechanisms of EG’s non-cell autonomous impact on axon-integrity. A particular focus is placed on emerging evidence suggesting that EG nurture long axons by virtue of their intimate association, release of trophic substances, and neurometabolic coupling. The correction of defects in these functions has the potential to stabilize axons in a variety of neuronal diseases in the peripheral nervous system and central nervous system (PNS and CNS).
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Affiliation(s)
- Bogdan Beirowski
- Department of Genetics, Washington University School of Medicine Saint Louis, MO, USA
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13
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Salehi Z, Hadiyan SP, Navidi R. Ciliary neurotrophic factor role in myelin oligodendrocyte glycoprotein expression in Cuprizone-induced multiple sclerosis mice. Cell Mol Neurobiol 2013; 33:531-5. [PMID: 23443463 DOI: 10.1007/s10571-013-9918-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 02/11/2013] [Indexed: 01/19/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system that leads to loss of myelin and oligodendrocytes and damage to axons. Myelin oligodendrocyte glycoprotein (MOG) is a minor component of the myelin sheath, but is an important autoantigen linked to the pathogenesis of MS. Ciliary neurotrophic factor (CNTF) has been shown to enhance the generation, maturation, and survival of oligodendrocytes in culture medium. The aim of this study was to demonstrate the role of CNTF on MOG expression in the cerebral cortex of Cuprizone-induced MS mice. The mice were treated by Cuprizone for five weeks in order to induce MS. The mice were then divided into 3 groups. The first group was injected subcutaneously (SC) by CNTF in the amount of 250 μg/kg BW per day. The second group (SHAM) was injected SC by normal saline and the third group was left without injection as the control group. After four weeks the mice were killed and the cerebral cortex was harvested and the expression of MOG was studied by Western blotting. The data from this study show that the MOG expression was significantly increased in the CNTF-injected group as compared to the other groups. It is concluded that CNTF increases the MOG expression and may be important in the pathophysiology of MS. It is also concluded that CNTF may play a role in the process of remyelination by inducing the MOG expression.
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Affiliation(s)
- Zivar Salehi
- Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran.
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Vetrivel U, Ravichandran SB, Kuppan K, Mohanlal J, Das UN, Narayanasamy A. Agonistic effect of polyunsaturated fatty acids (PUFAs) and its metabolites on brain-derived neurotrophic factor (BDNF) through molecular docking simulation. Lipids Health Dis 2012; 11:109. [PMID: 22943296 PMCID: PMC3477081 DOI: 10.1186/1476-511x-11-109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 08/27/2012] [Indexed: 01/19/2023] Open
Abstract
Background Brain-derived neurotrophic factor (BDNF) is a potent neurotrophic factor that is implicated in the regulation of food intake and body weight. Polyunsaturated fatty acids (PUFAs) localised in cell membranes have been shown to alter the levels of BDNF in the brain, suggesting that PUFAs and BDNF could have physical interaction with each other. To decipher the molecular mechanism through which PUFAs modulates BDNF’s activity, molecular docking was performed for BDNF with PUFAs and its metabolites, with 4-Methyl Catechol as a control. Results Inferring from molecular docking studies, lipoxin A4 (LXA4), and a known anti-inflammatory bioactive metabolite derived from PUFAs, with a binding energy of −3.98 Kcal/mol and dissociation constant of 1.2mM showed highest binding affinity for BDNF in comparison to other PUFAs and metabolites considered in the study. Further, the residues Lys 18, Thr 20, Ala 21, Val 22, Phe 46, Glu 48, Lys 50, Lys 58, Thr 75, Gln 77, Arg 97 and Ile 98 form hot point motif, which on interaction enhances BDNF’s function. Conclusion These results suggest that PUFAs and their metabolites especially, LXA4, modulate insulin resistance by establishing a physical interaction with BDNF. Similar interaction(s) was noted between BDNF and resolvins and protectins but were of lesser intensity compared to LXA4.
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Affiliation(s)
- Umashankar Vetrivel
- Department of Bioinformatics, Vision Research Foundation, Chennai 600006, India
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Yan Y, Sun HH, Hunter DA, Mackinnon SE, Johnson PJ. Efficacy of Short-Term FK506 Administration on Accelerating Nerve Regeneration. Neurorehabil Neural Repair 2012; 26:570-80. [DOI: 10.1177/1545968311431965] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Background. The slow rate of nerve regeneration following injury can cause extended muscle denervation, leading to irreversible muscle atrophy, fibrosis, and destruction of motor endplates. The immunosuppressant FK506 (tacrolimus) has been shown to accelerate the rate of nerve regeneration and functional recovery. However, the toxic and immunosuppressive properties of FK506 make it undesirable for long-term use. Objective. To take advantage of the regeneration-enhancing effects of FK506 but avoid the potential adverse effects of long-term administration, the current study evaluates and quantifies the efficacy of short-term FK506 treatment in rat models. Methods. Clinically relevant transection and graft models were evaluated, and walking track analysis (WTA) was used to evaluate functional recovery. FK506 was administered for 5 and 10 days post transection injury and 10 and 20 days post graft injury. Both groups involving a short course were compared with the continuous administration group. Results. In the transection model, FK506 was administered for 5 and 10 days postoperatively. WTA demonstrated that 10 days of FK506 administration was sufficient to reduce functional recovery time by 29% compared with negative controls. In the graft model, FK506 was administered for 10 and 20 days postoperatively. Short treatment courses of 10 and 20 days reduced recovery time by 15% and 21%, respectively, compared with negative controls. Analysis of blood–nerve barrier (BNB) integrity demonstrated that FK506 facilitated early reconstitution of the BNB. Conclusions. The results of this study indicate that short-term FK506 delivery following nerve injury imparts a significant therapeutic effect.
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Affiliation(s)
- Ying Yan
- Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Hank H. Sun
- Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Daniel A. Hunter
- Washington University in St Louis School of Medicine, St Louis, MO, USA
| | | | - Philip J. Johnson
- Washington University in St Louis School of Medicine, St Louis, MO, USA
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Arai K, Pham LDD, Lo EH. Experimental Platforms for Assessing White Matter Pathophysiology in Stroke. Transl Stroke Res 2012. [DOI: 10.1007/978-1-4419-9530-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Arai K, Lok J, Guo S, Hayakawa K, Xing C, Lo EH. Cellular mechanisms of neurovascular damage and repair after stroke. J Child Neurol 2011; 26:1193-8. [PMID: 21628695 PMCID: PMC3530192 DOI: 10.1177/0883073811408610] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The biological processes underlying stroke are complex, and patients have a narrow repertoire of therapeutic opportunities. After the National Institutes of Health (NIH) convened the Stroke Progress Review Group in 2001, stroke research shifted from having a purely neurocentric focus to adopting a more integrated view wherein dynamic interactions between all cell types contribute to function and dysfunction in the brain. This so-called "neurovascular unit" provides a conceptual framework that emphasizes cell-cell interactions between neuronal, glial, and vascular elements. Under normal conditions, signaling within the neurovascular unit helps maintain homeostasis. After stroke, cell-cell signaling is disturbed, leading to pathophysiology. More recently, emerging data now suggest that these cell-cell signaling mechanisms may also mediate parallel processes of neurovascular remodeling during stroke recovery. Because plasticity is a signature feature of the young and developing brain, these concepts may have special relevance to how the pediatric brain responds after stroke.
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Affiliation(s)
- Ken Arai
- The Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts, USA.
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Zhang J, Kramer EG, Asp L, Dutta DJ, Navrazhina K, Pham T, Mariani JN, Argaw AT, Melendez-Vasquez CV, John GR. Promoting myelin repair and return of function in multiple sclerosis. FEBS Lett 2011; 585:3813-20. [PMID: 21864535 DOI: 10.1016/j.febslet.2011.08.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 01/06/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. Conduction block in demyelinated axons underlies early neurological symptoms, but axonal transection and neuronal loss are believed to be responsible for more permanent chronic deficits. Several therapies are approved for treatment of relapsing-remitting MS, all of which are immunoregulatory and clinically proven to reduce the rate of lesion formation and exacerbation. However, existing approaches are only partially effective in preventing the onset of disability in MS patients, and novel treatments to protect myelin-producing oligodendrocytes and enhance myelin repair may improve long-term outcomes. Studies in vivo in genetically modified mice have assisted in the characterization of mechanisms underlying the generation of neuropathology in MS patients, and have identified potential avenues for oligodendrocyte protection and myelin repair. However, no treatments are yet approved that target these areas directly, and in addition, the relationship between demyelination and axonal transection in the lesions of the disease remains unclear. Here, we review translational research targeting oligodendrocyte protection and myelin repair in models of autoimmune demyelination, and their potential relevance as therapies in MS.
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Affiliation(s)
- Jingya Zhang
- Corinne Goldsmith Dickinson Center for MS, Mount Sinai School of Medicine, New York, NY 10029, USA
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Gudi V, Škuljec J, Yildiz Ö, Frichert K, Skripuletz T, Moharregh-Khiabani D, Voß E, Wissel K, Wolter S, Stangel M. Spatial and temporal profiles of growth factor expression during CNS demyelination reveal the dynamics of repair priming. PLoS One 2011; 6:e22623. [PMID: 21818353 PMCID: PMC3144923 DOI: 10.1371/journal.pone.0022623] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/26/2011] [Indexed: 11/18/2022] Open
Abstract
Demyelination is the cause of disability in various neurological disorders. It is therefore crucial to understand the molecular regulation of oligodendrocytes, the myelin forming cells in the CNS. Growth factors are known to be essential for the development and maintenance of oligodendrocytes and are involved in the regulation of glial responses in various pathological conditions. We employed the well established murine cuprizone model of toxic demyelination to analyze the expression of 13 growth factors in the CNS during de- and remyelination. The temporal mRNA expression profile during demyelination and the subsequent remyelination were analyzed separately in the corpus callosum and cerebral cortex using laser microdissection and real-time PCR techniques. During demyelination a similar pattern of growth factor mRNA expression was observed in both areas with a strong up-regulation of NRG1 and GDNF and a slight increase of CNTF in the first week of cuprizone treatment. HGF, FGF-2, LIF, IGF-I, and TGF-ß1 were up-regulated mainly during peak demyelination. In contrast, during remyelination there were regional differences in growth factor mRNA expression levels. GDNF, CNTF, HGF, FGF-2, and BDNF were elevated in the corpus callosum but not in the cortex, suggesting tissue differences in the molecular regulation of remyelination in the white and grey matter. To clarify the cellular source we isolated microglia from the cuprizone lesions. GDNF, IGF-1, and FGF mRNA were detected in the microglial fraction with a temporal pattern corresponding to that from whole tissue PCR. In addition, immunohistochemical analysis revealed IGF-1 protein expression also in the reactive astrocytes. CNTF was located in astrocytes. This study identified seven different temporal expression patterns for growth factors in white and grey matter and demonstrated the importance of early tissue priming and exact orchestration of different steps during callosal and cortical de- and remyelination.
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Affiliation(s)
- Viktoria Gudi
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Jelena Škuljec
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Özlem Yildiz
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | | | | | | | - Elke Voß
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Kirsten Wissel
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Sabine Wolter
- Department of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Martin Stangel
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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Zhang J, Kramer EG, Mahase S, Dutta DJ, Bonnamain V, Argaw AT, John GR. Targeting oligodendrocyte protection and remyelination in multiple sclerosis. ACTA ACUST UNITED AC 2011; 78:244-57. [PMID: 21425268 DOI: 10.1002/msj.20244] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Multiple sclerosis is an inflammatory demyelinating disease of the brain and spinal cord with a presumed autoimmune etiology. Conduction block in demyelinated axons underlies early neurological symptoms, whereas axonal transection is believed responsible for more permanent later deficits. Approved treatments for the disease are immunoregulatory and reduce the rate of lesion formation and clinical exacerbation, but are only partially effective in preventing the onset of disability in multiple sclerosis patients. Approaches that directly protect myelin-producing oligodendrocytes and enhance remyelination may improve long-term outcomes and reduce the rate of axonal transection. Studies in genetically modified animals have improved our understanding of mechanisms underlying central nervous system pathology in multiple sclerosis models, and have identified pathways that regulate oligodendrocyte viability and myelin repair. However, although clinical trials are ongoing, many have been unsuccessful, and no treatments are yet approved that target these areas in multiple sclerosis. In this review, we examine avenues for oligodendrocyte protection and endogenous myelin repair in animal models of demyelination and remyelination, and their relevance as therapeutics in human patients.
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Affiliation(s)
- Jingya Zhang
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis, Mount Sinai School of Medicine, New York, NY, USA
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21
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Wan L, Xia R, Ding W. Short-term low-frequency electrical stimulation enhanced remyelination of injured peripheral nerves by inducing the promyelination effect of brain-derived neurotrophic factor on Schwann cell polarization. J Neurosci Res 2011; 88:2578-87. [PMID: 20648648 DOI: 10.1002/jnr.22426] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Electrical stimulation (ES) has been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. However, the effect of ES on peripheral remyelination after nerve damage has been investigated less well, and the mechanism underlying its action remains unclear. In the present study, the crush-injured sciatic nerves in rats were subjected to 1 hr of continuous ES (20 Hz, 100 microsec, 3 V). Electron microscopy and nerve morphometry were performed to investigate the extent of regenerated nerve myelination. The expression profiles of P0, Par-3, and brain-derived neurotrophic factor (BDNF) in the injuried sciatic nerves and in the dorsal root ganglion neuron/Schwann cell cocultures were examined by Western blotting. Par-3 localization in the sciatic nerves was determined by immunohistochemistry to demonstrate Schwann cell polarization during myelination. We reported that 20-Hz ES increased the number of myelinated fibers and the thickness myelin sheath at 4 and 8 weeks postinjury. P0 level in the ES-treated groups, both in vitro and in vivo, was enhanced compared with the controls. The earlier peak of Par-3 in the ES-treated groups indicated an earlier initiation of Schwann cell myelination. Additionally, ES significantly elevated BDNF expression in nerve tissues and in cocultures. ES on the site of nerve injury potentiates axonal regrowth and myelin maturation during peripheral nerve regeneration. Furthermore, the therapeutic actions of ES on myelination are mediated via enhanced BDNF signals, which drive the promyelination effect on Schwann cells at the onset of myelination.
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Affiliation(s)
- Lidan Wan
- Department of Anatomy, Shanghai Jiao Tong University School of Medicine, Shanghai,
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22
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Alteration of growth factors and neuronal death in diabetic retinopathy: what we have learned so far. Mol Vis 2011; 17:300-8. [PMID: 21293735 PMCID: PMC3032276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 01/25/2011] [Indexed: 10/29/2022] Open
Abstract
PURPOSE Diabetic retinopathy (DR) is a leading cause of blindness in American adults. Over the years, DR has been perceived as a vascular disease characterized by vascular permeability, macular edema, and neovascularization that can lead to blindness. Relatively new research on neurodegeneration is expanding our views of the pathogenesis of DR. Evidence has begun to point to the fact that even before vascular complications begin to manifest, neuronal cell death and dysfunction have already begun. Based on the literature and our own studies, we address whether neuronal death is associated with loss of neurotrophic support due to less production of a given growth factor or due to impairment of its signaling events regardless of the level of the growth factor itself. METHODS In this article we aimed to review the literature that looks at the neuronal side of DR and whether retinal neurons are adversely affected due to the lack of neurotrophic levels or activity. In particular, we examine the research looking at insulin, insulin-like growth factor, vascular endothelial growth factor, pigment epithelium-derived growth factor, brain-derived neurotrophic factor, and nerve growth factor. RESULTS Research shows that insulin has neurotrophic properties and that the loss of its pro-survival pathways may have a role in diabetic retinopathy. There is also evidence to suggest that exogenously administered insulin may have a role in the treatment of DR. Insulin-like growth factor has been shown to have a role in retinal neurogenesis and there is early evidence that it may also have neuroprotective effects. While there is evidence of neuroprotective effects of vascular endothelial growth factor, paradoxically, there is also an increased amount of apoptotic activity in retinal neurons despite an increased level of VEGF in the diabetic eye. Further research is necessary to elucidate the exact mechanisms involved. Pigment epithelium derived growth factor has retinal neuroprotective effects and shows evidence that it may be an avenue for future therapeutic use in DR. Brain-derived growth factor has been shown to have neuroprotective effects in the retina and there is also some evidence in diabetic rats that it may have some therapeutic potential in treating DR. Nerve growth factor has also been shown to have neuroprotective effects and research has begun to elucidate some of the pathways and mechanisms through which these effects occur. CONCLUSIONS Research has shown that there is some degree of neuronal death involved in DR. It is also evident that there are many growth factors involved in this process. Some of these growth factors have shown some potential as future therapeutic targets in DR. These findings should encourage further investigation into the mechanism of these growth factors, their potential for therapy, and the possibility of a new horizon in the clinical care of DR.
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Abstract
The myelin sheath wraps large axons in both the CNS and the PNS, and is a key determinant of efficient axonal function and health. Myelin is targeted in a series of diseases, notably multiple sclerosis (MS). In MS, demyelination is associated with progressive axonal damage, which determines the level of patient disability. The few treatments that are available for combating myelin damage in MS and related disorders, which largely comprise anti-inflammatory drugs, only show limited efficacy in subsets of patients. More-effective treatment of myelin disorders will probably be accomplished by early intervention with combinatorial therapies that target inflammation and other processes-for example, signaling pathways that promote remyelination. Indeed, evidence suggests that such pathways might be impaired in pathology and, hence, contribute to the failure of remyelination in such diseases. In this article, we review the molecular basis of signaling pathways that regulate myelination in the CNS and PNS, with a focus on signals that affect differentiation of myelinating glia. We also discuss factors such as extracellular molecules that act as modulators of these pathways. Finally, we consider the few preclinical and clinical trials of agents that augment this signaling.
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Abstract
Stroke is one of the leading causes of death and disability in developed countries. Since protecting neurons alone is not sufficient for stroke therapy, research has shifted to the rescue of multiple cell types in the brain. In particular, attention has focused on the study of how cerebral blood vessels and brain cells communicate with each other. Recent findings suggest that cerebral endothelial cells may secrete trophic factors that nourish neighboring cells. Although data are strongest in terms of supporting endothelial-neuronal interactions, it is likely that similar interactions occur in white matter as well. In this mini-review, we summarize recent advances in the dissection of cell-cell interactions in white matter. We examine two key concepts. First, trophic interactions between vessels and oligodendrocytes (OLGs) and oligodendrocyte precursor cells (OPCs) play critical roles in white matter homeostasis. Second, cell-cell trophic coupling is disturbed under diseased conditions that incur oxidative stress. White matter pathophysiology is very important in stroke. A deeper understanding of the mechanisms of oligovascular signaling in normal and pathologic conditions may lead us to new therapeutic targets for stroke and other neurodegenerative diseases.
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Affiliation(s)
- Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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25
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Kramer F, Stöver T, Warnecke A, Diensthuber M, Lenarz T, Wissel K. BDNF mRNA expression is significantly upregulated in vestibular schwannomas and correlates with proliferative activity. J Neurooncol 2009; 98:31-9. [PMID: 19937367 DOI: 10.1007/s11060-009-0063-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 11/09/2009] [Indexed: 01/20/2023]
Abstract
The expression of neurotrophic factors, such as artemin, glial cell line-derived neurotrophic factor (GDNF), neurturin, transforming growth factors (TGF)-beta1/beta2 and brain-derived neurotrophic factor (BDNF), is enhanced in vestibular schwannomas compared to peripheral nerves. Furthermore, this upregulation may correlate with mitotic activity. Vestibular schwannoma arising from Schwann cells of the vestibular nerve are mostly benign and slow-growing. Most of the pathogenic mechanisms regulating the vestibular schwannoma growth process are unknown. An impaired growth regulation and imbalance between mitosis and apoptosis can be assumed. However, molecular mechanisms interfering with regulation of the vestibular schwannoma growth also modulated by mitogenic factors have to be identified. Neurotrophic factors are involved in regulation of developmental processes in neuronal tissues and regeneration after peripheral nerve trauma and also reveal mitogenic effects on glial cell populations. Gene expression profiles of artemin, BDNF, GDNF, TGF-beta1/beta2 and Ret were determined in the vestibular schwannoma in comparison to the peripheral nerve tissues by using semiquantitative RT-PCR. The expression data were correlated to the proliferation-associated Ki-67 labelling index. A significant higher BDNF expression was observed in the vestibular schwannoma, whereas gene expression of artemin and GDNF was upregulated in peripheral nerves. The correlation between LI and BDNF, TGF-beta1 and Ret was found to be significant in the vestibular schwannoma. Our results demonstrate a coherence between BDNF expression and proliferative activity in the vestibular schwannoma. Based on these results, we propose a pivotal role for BDNF in modulating the vestibular schwannoma growth.
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Affiliation(s)
- Frauke Kramer
- Department of Gynecology and Obstetrics, Hannover Medical School, Hannover, Germany
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Abstract
There is a growing awareness that natural vitamins (with the only exception of pantothenic acid) positively or negatively modulate the synthesis of some cytokines and growth factors in the CNS, and various mammalian cells and organs. As natural vitamins are micronutrients in the human diet, studying their effects can be considered a part of nutritional genomics or nutrigenomics. A given vitamin selectively modifies the synthesis of only a few cytokines and/or growth factors, although the same cytokine and/or growth factor may be regulated by more than one vitamin. These effects seem to be independent of the effects of vitamins as coenzymes and/or reducing agents, and seem to occur mainly at genomic and/or epigenetic level, and/or by modulating NF-kappaB activity. Although most of the studies reviewed here have been based on cultured cell lines, but their findings have been confirmed by some key in vivo studies. The CNS seems to be particularly involved and is severely affected by most avitaminoses, especially in the case of vitamin B(12). However, the vitamin-induced changes in cytokine and growth factor synthesis may initiate a cascade of events that can affect the function, differentiation, and morphology of the cells and/or structures not only in the CNS, but also elsewhere because most natural vitamins, cytokines, and growth factors cross the blood-brain barrier. As cytokines are essential to CNS-immune and CNS-hormone system communications, natural vitamins also interact with these circuits. Further studies of such vitamin-mediated effects could lead to vitamins being used for the treatment of diseases which, although not true avitaminoses, involve an imbalance in cytokine and/or growth factor synthesis.
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Affiliation(s)
- Giuseppe Scalabrino
- Laboratory of Neuropathology, 'Città Studi' Department, Faculty of Medicine and Surgery, University of Milan, Milan, Italy.
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27
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Scalabrino G. The multi-faceted basis of vitamin B12 (cobalamin) neurotrophism in adult central nervous system: Lessons learned from its deficiency. Prog Neurobiol 2009; 88:203-20. [DOI: 10.1016/j.pneurobio.2009.04.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 03/03/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
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Sivilia S, Giuliani A, Fernández M, Turba ME, Forni M, Massella A, De Sordi N, Giardino L, Calzà L. Intravitreal NGF administration counteracts retina degeneration after permanent carotid artery occlusion in rat. BMC Neurosci 2009; 10:52. [PMID: 19473529 PMCID: PMC2699342 DOI: 10.1186/1471-2202-10-52] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 05/27/2009] [Indexed: 01/19/2023] Open
Abstract
Background The neurotrophin nerve growth factor (NGF) is produced by different cell types in the anterior and posterior eye, exerting a neuroprotective role in the adult life. The visual system is highly sensitive to NGF and the retina and optic nerve provides suitable subjects for the study of central nervous system degeneration. The model of bilateral carotid occlusion (two-vessel occlusion, 2VO) is a well-established model for chronic brain hypoperfusion leading to brain capillary pathology, to retina and optic nerve degeneration. In order to study if a single intravitreal injection of NGF protects the retina and the optic nerve from degeneration during systemic circulatory diseases, we investigated morphological and molecular changes occurring in the retina and optic nerve of adult rats at different time-points (8, 30 and 75 days) after bilateral carotid occlusion. Results We demonstrated that a single intravitreal injection of NGF (5 μg/3 μl performed 24 hours after 2VO ligation) has a long-lasting protective effect on retina and optic nerve degeneration. NGF counteracts retinal ganglion cells degeneration by early affecting Bax/Bcl-2 balance- and c-jun- expression (at 8 days after 2VO). A single intravitreal NGF injection regulates the demyelination/remyelination balance after ischemic injury in the optic nerve toward remyelination (at 75 days after 2VO), as indicated by the MBP expression regulation, thus preventing optic nerve atrophy and ganglion cells degeneration. At 8 days, NGF does not modify 2VO-induced alteration in VEFG and related receptors mRNA expression. Conclusion The protective effect of exogenous NGF during this systemic circulatory disease seems to occur also by strengthening the effect of endogenous NGF, the synthesis of which is increased by vascular defect and also by the mechanical lesion associated with NGF or even vehicle intraocular delivery.
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Mirowska-Guzel D. The role of neurotrophic factors in the pathology and treatment of multiple sclerosis. Immunopharmacol Immunotoxicol 2009; 31:32-8. [PMID: 18792835 DOI: 10.1080/08923970802379819] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Multiple sclerosis (MS) is a chronic demyelinating disease of primary autoimmune origin with essential component of subsequent axonal degeneration. It has been found that inflammatory cells crucial for MS pathogenesis are able to release neurotrophic factors (NFs). Thus the concept of neuroprotective effect of inflammation has arisen. Over recent years, increasing number of studies has revealed that NFs play an important role in MS and its animal model - experimental autoimmune encephalomyelitis (EAE). In the current review the evidence for the role of NFs in MS pathogenesis the same as their remarkable potential in MS therapy is presented.
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Chabas JF, Alluin O, Rao G, Garcia S, Lavaut MN, Risso JJ, Legre R, Magalon G, Khrestchatisky M, Marqueste T, Decherchi P, Feron F. Vitamin D2 potentiates axon regeneration. J Neurotrauma 2009; 25:1247-56. [PMID: 18986226 DOI: 10.1089/neu.2008.0593] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To date, the use of autograft tissue remains the "gold standard" technique for repairing transected peripheral nerves. However, the recovery is suboptimal, and neuroactive molecules are required. In the current study, we focused our attention on vitamin D, an FDA-approved molecule whose neuroprotective and neurotrophic actions are increasingly recognized. We assessed the therapeutic potential of ergocalciferol--the plant-derived form of vitamin D, named vitamin D2--in a rat model of peripheral nerve injury and repair. The left peroneal nerve was cut out on a length of 10 mm and immediately autografted in an inverted position. After surgery, animals were treated with ergocalciferol (100 IU/kg/day) and compared to untreated animals. Functional recovery of hindlimb was measured weekly, during 10 weeks post-surgery, using a walking track apparatus and a numerical camcorder. At the end of this period, motor and sensitive responses of the regenerated axons were calculated and histological analysis was performed. We observed that vitamin D2 significantly (i) increased axogenesis and axon diameter; (ii) improved the responses of sensory neurons to metabolites such as KCl and lactic acid; and (iii) induced a fast-to-slow fiber type transition of the Tibialis anterior muscle. In addition, functional recovery was not impaired by vitamin D supplementation. Altogether, these data indicate that vitamin D potentiates axon regeneration. Pharmacological studies with various concentrations of the two forms of vitamin D (ergocalciferol vs. cholecalciferol) are now required before recommending this molecule as a potential supplemental therapeutic approach following nerve injury.
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Affiliation(s)
- Jean-François Chabas
- Neurobiologie des Interactions Cellulaires et Neurophysiopathologie, CNRS UMR 6184, Université de la Méditerranée, Service de Chirurgie de la Main, Hopitaux de Marseille, Marseille, France
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31
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Chabas JF, Alluin O, Rao G, Garcia S, Lavaut MN, Legré R, Magalon G, Marqueste T, Feron F, Decherchi P. FK506 Induces Changes in Muscle Properties and Promotes Metabosensitive Nerve Fiber Regeneration. J Neurotrauma 2009; 26:97-108. [DOI: 10.1089/neu.2008.0695] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Jean-François Chabas
- Neurobiologie des Interactions Cellulaires et Neurophysiopathologie (UMR CNRS 6184), Université de la Méditerranée (Aix-Marseille II), Faculté de Médecine Nord, Institut Fédératif de Recherche Jean Roche, Marseille, France
- Services de Chirurgie de la Main, Chirurgie Plastique et Réparatrice des Membres, Assistance Publique–Hôpitaux de Marseille, Hôpital de la Conception, Marseille, France
| | - Olivier Alluin
- Institut des Sciences du Mouvement: Etienne-Jules Marey (UMR CNRS 6233), Université de la Méditerranée (Aix-Marseille II), Parc Scientifique et Technologique de Luminy–Faculté des Sciences du Sport de Marseille, France
| | - Guillaume Rao
- Institut des Sciences du Mouvement: Etienne-Jules Marey (UMR CNRS 6233), Université de la Méditerranée (Aix-Marseille II), Parc Scientifique et Technologique de Luminy–Faculté des Sciences du Sport de Marseille, France
| | - Stéphane Garcia
- Service Hospitalier d'Anatomie et Cytologie Pathologiques Humaines, Université de la Méditerranée (Aix-Marseille II), Assistance Publique–Hôpitaux de Marseille, Institut de Cancérologie et d'Immunologie de Marseille, Faculté de Médecine Nord, Marseille, France
| | - Marie-Noëlle Lavaut
- Service Hospitalier d'Anatomie et Cytologie Pathologiques Humaines, Université de la Méditerranée (Aix-Marseille II), Assistance Publique–Hôpitaux de Marseille, Institut de Cancérologie et d'Immunologie de Marseille, Faculté de Médecine Nord, Marseille, France
| | - Régis Legré
- Services de Chirurgie de la Main, Chirurgie Plastique et Réparatrice des Membres, Assistance Publique–Hôpitaux de Marseille, Hôpital de la Conception, Marseille, France
| | - Guy Magalon
- Services de Chirurgie de la Main, Chirurgie Plastique et Réparatrice des Membres, Assistance Publique–Hôpitaux de Marseille, Hôpital de la Conception, Marseille, France
| | - Tanguy Marqueste
- Institut des Sciences du Mouvement: Etienne-Jules Marey (UMR CNRS 6233), Université de la Méditerranée (Aix-Marseille II), Parc Scientifique et Technologique de Luminy–Faculté des Sciences du Sport de Marseille, France
| | - François Feron
- Neurobiologie des Interactions Cellulaires et Neurophysiopathologie (UMR CNRS 6184), Université de la Méditerranée (Aix-Marseille II), Faculté de Médecine Nord, Institut Fédératif de Recherche Jean Roche, Marseille, France
| | - Patrick Decherchi
- Institut des Sciences du Mouvement: Etienne-Jules Marey (UMR CNRS 6233), Université de la Méditerranée (Aix-Marseille II), Parc Scientifique et Technologique de Luminy–Faculté des Sciences du Sport de Marseille, France
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Katz JS, Burdick JA. Hydrogel mediated delivery of trophic factors for neural repair. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2008; 1:128-139. [DOI: 10.1002/wnan.10] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Joshua S. Katz
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104, USA
| | - Jason A. Burdick
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104, USA
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Oligodendrocyte differentiation and implantation: new insights for remyelinating cell therapy. Curr Opin Neurol 2008; 21:607-14. [PMID: 18769257 DOI: 10.1097/wco.0b013e32830f1e50] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW Recent research on oligodendrocyte development has yielded new insights on the involvement of morphogens and differentiation factors in oligodendrogenesis. This knowledge has improved strategies to control neural stem cell-derived oligodendrocyte differentiation and functional maturation in vitro. In this review, we highlight the current knowledge on oligodendrocyte differentiation and discuss the novel possibilities of neural stem cell-derived oligodendrocytes for graft-based remyelination therapy, for example, for multiple sclerosis. RECENT FINDINGS Detailed insight into the cellular and molecular processes of embryonic and adult oligodendrogenesis has extended considerably in the past 2 years. Application of extrinsic factors and manipulation of intrinsic factors in neural stem cells have yielded convincing oligodendrocyte differentiation strategies. In addition, the recent groundbreaking developments regarding induced pluripotent stem cells generated from easily accessible somatic cells seem to offer an almost inexhaustible source for transplantable, autologous neural stem cells. Moreover, new approaches to optimize the implantation site for oligodendrocyte survival and functionality have improved the feasibility of stem cell-based oligodendrocyte replacement therapy. SUMMARY Loss of myelin in demyelinating diseases is only partly restored by endogenous oligodendrocyte precursor cells. Application of optimally functional, neural stem cell-derived oligodendrocyte precursors at the lesion site has become a realistic therapeutic approach to promote the remyelination process.
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Abstract
Oligodendrocytes and Schwann cells are highly specialized glial cells that wrap axons with a multilayered myelin membrane for rapid impulse conduction. Investigators have recently identified axonal signals that recruit myelin-forming Schwann cells from an alternate fate of simple axonal engulfment. This is the evolutionary oldest form of axon-glia interaction, and its function is unknown. Recent observations suggest that oligodendrocytes and Schwann cells not only myelinate axons but also maintain their long-term functional integrity. Mutations in the mouse reveal that axonal support by oligodendrocytes is independent of myelin assembly. The underlying mechanisms are still poorly understood; we do know that to maintain axonal integrity, mammalian myelin-forming cells require the expression of some glia-specific proteins, including CNP, PLP, and MAG, as well as intact peroxisomes, none of which is necessary for myelin assembly. Loss of glial support causes progressive axon degeneration and possibly local inflammation, both of which are likely to contribute to a variety of neuronal diseases in the central and peripheral nervous systems.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany.
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Lang EM, Schlegel N, Reiners K, Hofmann GO, Sendtner M, Asan E. Single-Dose Application of CNTF and BDNF Improves Remyelination of Regenerating Nerve Fibers after C7 Ventral Root Avulsion and Replantation. J Neurotrauma 2008; 25:384-400. [DOI: 10.1089/neu.2007.0396] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Eva M. Lang
- Department of Plastic and Hand Surgery, Albert Ludwigs University, Freiburg, Germany
| | - Nicholas Schlegel
- Institute of Anatomy and Cell Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Karlheinz Reiners
- Department of Neurology, University of Wuerzburg, Wuerzburg, Germany
| | - Gunther O. Hofmann
- Clinic of Trauma Surgery, Friedrich Schiller University, Jena, and BG-TraumaCenter, Halle, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University of Wuerzburg, Wuerzburg, Germany
| | - Esther Asan
- Institute of Anatomy and Cell Biology, University of Wuerzburg, Wuerzburg, Germany
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Sarchielli P, Di Filippo M, Ercolani MV, Chiasserini D, Mattioni A, Bonucci M, Tenaglia S, Eusebi P, Calabresi P. Fibroblast growth factor-2 levels are elevated in the cerebrospinal fluid of multiple sclerosis patients. Neurosci Lett 2008; 435:223-8. [DOI: 10.1016/j.neulet.2008.02.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 02/17/2008] [Accepted: 02/20/2008] [Indexed: 11/30/2022]
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Althaus HH, Klöppner S, Klopfleisch S, Schmitz M. Oligodendroglial Cells and Neurotrophins: A Polyphonic Cantata in Major and Minor. J Mol Neurosci 2008; 35:65-79. [DOI: 10.1007/s12031-008-9053-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 01/25/2008] [Indexed: 01/12/2023]
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Abstract
PURPOSE OF REVIEW Schizophrenia is a complex genetic disorder, caused by multiple genetic and environmental factors. Recently, studies have focused on testing specific genetic markers in a known candidate gene for association with endophenotypes. These are measurable characteristics of a disorder that are assumed to be closer to the action of the gene, resulting in higher genetic signal-to-noise ratios. Structural brain parameters have been shown to be useful endophenotypes for studies in psychiatric illnesses. RECENT FINDINGS After reviewing the available studies on the influence of genotype on brain volume in schizophrenia, it is evident that the BDNF and COMT genes are clearly favourites for genetic imaging studies. Results from these studies seem to be quite consistent, with the same associated alleles and direction of brain volume changes. The most frequently investigated polymorphisms suggest that sample sizes of approximately 50-100 patients are sufficient to report consistent findings. Considering the ongoing discussion about the sample size necessary to detect significant associations, however, larger sample sizes are needed. SUMMARY There is sufficient evidence to defend the use of structural neuroimaging as an endophenotype to investigate a complex phenotype such as schizophrenia despite the notion that, so far, no single causal pathway emerges from these studies. Replication studies and larger numbers of patients are essential in this respect.
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Abstract
OBJECTIVES After axotomy, Schwann cells (SCs), required for successful nerve regeneration, undergo a number of cellular changes including dedifferentiation, proliferation, expression of molecules that support axon growth, and apoptosis. This study investigated the role of p75, sortilin, and proneurotrophins in SC survival after facial nerve (FN) axotomy. STUDY DESIGN Preliminary animal study. METHODS With use of FN SCs, expression of p75 and its coreceptor sortilin were quantified by immunofluorescence on days 12, 22, and 52 after axotomy in vivo and by Western blot in vitro. Contralateral FNs served as a control. SC apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). To verify a causative role for p75 in FN SC death, cultured FN SCs were treated with pro-nerve growth factor (NGF), and apoptosis was determined by TUNEL. RESULTS Expression of p75 and sortilin increased in FN SCs distal (P < .05) to the axotomy compared with the contralateral controls for all time points. SC apoptosis also significantly increased in the distal segment compared with the contralateral and proximal portions (P < .05). ProNGF, a p75 ligand, increased apoptosis and p75 expression in primary FN SC cultures. CONCLUSION FN axotomy increases p75 and sortilin expression in SCs, which correlates with increased apoptosis. These findings suggest roles for p75 and sortilin in SC loss after FN injury. Sortilin is a novel target in promoting FN healing after injury.
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Mirowska-Guzel D, Mach A, Gromadzka G, Czlonkowski A, Czlonkowska A. BDNF A196G and C270T gene polymorphisms and susceptibility to multiple sclerosis in the polish population. Gender differences. J Neuroimmunol 2008; 193:170-2. [DOI: 10.1016/j.jneuroim.2007.10.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 10/17/2007] [Accepted: 10/17/2007] [Indexed: 11/16/2022]
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Abstract
Neurotrophins provide trophic and tropic support for different neuronal subpopulations in the developing and adult nervous systems. Expression of the neurotrophins and their receptors can be altered in several different disease or injury states that impact upon the functions in the central and peripheral nervous systems. The intracellular signals used by the neurotrophins are triggered by ligand binding to the cell surface Trk and p75NTR receptors. In general, signals emanating from Trk receptors support survival, growth and synaptic strengthening, while those emanating from p75NTR induce apoptosis, attenuate growth and weaken synaptic signaling. Mature neurotrophins are the preferred ligand for Trk proteins while p75NTR binds preferentially to the proneurotrophins and serves as a signaling component of the receptor complex for growth inhibitory molecules of central nervous system myelin [ie, myelin-associated glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgP) and Nogo]. The functional antagonism between Trk and p75NTR signaling may significantly impact the pathogenesis of human neurodevelopmental and neurodegenerative diseases and further complicate therapeutic uses of exogenous neurotrophins. The potential for each is discussed in this review.
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Affiliation(s)
- Jeffery L Twiss
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803, USA.
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Abstract
Peripheral neuropathy is a common disorder seen in general neurology and neuromuscular specialty clinics. Treatment options directed at the underlying cause can only be offered in a handful of conditions, such as those with possible autoimmune etiology. The remainder fall into the idiopathic or genetic category with no known treatment. This review surveys the evidence supporting the rationale for the therapeutic use of neurotrophins and other neurotrophic factors in these disorders in relationship to the underlying pathobiological process. Previous clinical trials are assessed, and increasingly better understood and appreciated therapeutic potential of neurotrophins is emphasized.
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Affiliation(s)
- Zarife Sahenk
- Neuromuscular Pathology, The Ohio State University, Columbus Children's Research Institute, Neuromuscular Program, Columbus, Ohio 43205, USA.
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Abstract
Neurotrophic factors (NTFs) have the unique potential to support neuronal survival and to augment neuronal function in the injured and diseased nervous system. Numerous studies conducted over the last 20 years have provided evidence for the potent therapeutic potential of NTFs in animal models of neurodegenerative diseases. However, major obstacles for the therapeutic use of NTFs are the inability to deliver proteins across the blood-brain-barrier, and dose-limiting adverse effects resulting from the broad exposure of nontargeted structures to NTFs. Two recent developments have allowed NTFs' promise to be truly tested for the first time: first, recent improvements in viral vectors that allow the targeted delivery of NTFs while providing a long-lasting supply and sufficient therapeutic doses of NTFs; and second, improved animal models developed in recent years. In this review, we will discuss some of the potential therapeutic applications of NTFs in neurodegenerative diseases and the potential contribution of disturbed neurotrophic factor signaling to neurodegenerative diseases.
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Affiliation(s)
- Armin Blesch
- Department of Neurosciences-0626, Center for Neural Repair, University of California, San Diego, La Jolla, California 92093-0626, USA.
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