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Emery B, Wood TL. Regulators of Oligodendrocyte Differentiation. Cold Spring Harb Perspect Biol 2024; 16:a041358. [PMID: 38503504 PMCID: PMC11146316 DOI: 10.1101/cshperspect.a041358] [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] [Indexed: 03/21/2024]
Abstract
Myelination has evolved as a mechanism to ensure fast and efficient propagation of nerve impulses along axons. Within the central nervous system (CNS), myelination is carried out by highly specialized glial cells, oligodendrocytes. The formation of myelin is a prolonged aspect of CNS development that occurs well into adulthood in humans, continuing throughout life in response to injury or as a component of neuroplasticity. The timing of myelination is tightly tied to the generation of oligodendrocytes through the differentiation of their committed progenitors, oligodendrocyte precursor cells (OPCs), which reside throughout the developing and adult CNS. In this article, we summarize our current understanding of some of the signals and pathways that regulate the differentiation of OPCs, and thus the myelination of CNS axons.
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Affiliation(s)
- Ben Emery
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Teresa L Wood
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103, USA
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2
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Saitoh SS, Tanabe S, Muramatsu R. Circulating factors that influence the central nervous system remyelination. Curr Opin Pharmacol 2022; 62:130-136. [PMID: 34995894 DOI: 10.1016/j.coph.2021.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 12/31/2022]
Abstract
Injury in the central nervous system leads to neurological deficits, depending on the disruption of neural networks. Remyelination, which occurs partially and spontaneously, is a critical process in the regeneration of neural networks to recover from neurological deficits. Remyelination depends on the development of oligodendrocytes, including the proliferation of oligodendrocyte precursor cells (OPCs) and the differentiation of OPCs into mature oligodendrocytes to form myelin. OPC proliferation and differentiation are regulated by intracellular and extracellular mechanisms, and recent studies have demonstrated that circulating factors secreted from peripheral organs or infiltrated immune cells play a key role in controlling oligodendrocyte development following remyelination in adult mammals. In this review, we describe the beneficial and detrimental effects of systemic environments, such as circulating factors derived from peripheral organs and immune cells, on CNS remyelination.
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Affiliation(s)
- Steve S Saitoh
- Department of Molecular Pharmacology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan; Department of NCNP Brain Physiology and Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Shogo Tanabe
- Department of Molecular Pharmacology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
| | - Rieko Muramatsu
- Department of Molecular Pharmacology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan.
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3
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Liu S, Zhang W, Yang L, Zhou F, Liu P, Wang Y. Overexpression of bone morphogenetic protein 7 reduces oligodendrocytes loss and promotes functional recovery after spinal cord injury. J Cell Mol Med 2021; 25:8764-8774. [PMID: 34390115 PMCID: PMC8435414 DOI: 10.1111/jcmm.16832] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/03/2021] [Accepted: 07/22/2021] [Indexed: 12/04/2022] Open
Abstract
Spinal cord injury (SCI), as a severe disease with no effective therapeutic measures, has always been a hot topic for scientists. Bone morphogenetic protein 7 (BMP7), as a multifunctional cytokine, has been reported to exert protective effects on the nervous system. The present study aimed to investigate the neuroprotective effect and the potential mechanisms of BMP7 on rats that suffered SCI. Rat models of SCI were established by the modified Allen's method. Adeno‐associated virus (AAV) was injected at T9 immediately before SCI to overexpress BMP7. Results showed that the expression of BMP7 decreased in the injured spinal cords that were at the same time demyelinated. AAV‐BMP7 partly reversed oligodendrocyte (OL) loss, and it was beneficial to maintain the normal structure of myelin. The intervention group showed an increase in the number of axons and Basso‐Beattie‐Bresnahan scores. Moreover, double‐labelled immunofluorescence images indicated p‐Smad1/5/9 and p‐STAT3 in OLs induced by BMP7 might be involved in the protective effects of BMP7. These findings suggest that BMP7 may be a feasible therapy for SCI to reduce demyelination and promote functional recovery.
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Affiliation(s)
- Shuxin Liu
- Department of Pain Management and Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Zhang
- Department of Pain Management and Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Lin Yang
- Department of Pain Management and Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Fan Zhou
- Department of Pain Management and Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Peng Liu
- Department of Disease Prevention and Control, People's Liberation Army Joint Logistic Support Force 921th Hospital, Changsha, China
| | - Yaping Wang
- Department of Pain Management and Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, China
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4
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Chu T, Shields LB, Zeng W, Zhang YP, Wang Y, Barnes GN, Shields CB, Cai J. Dynamic glial response and crosstalk in demyelination-remyelination and neurodegeneration processes. Neural Regen Res 2021; 16:1359-1368. [PMID: 33318418 PMCID: PMC8284258 DOI: 10.4103/1673-5374.300975] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/09/2020] [Accepted: 08/28/2020] [Indexed: 12/15/2022] Open
Abstract
Multiple sclerosis is an autoimmune disease in which the immune system attacks the myelin sheath in the central nervous system. It is characterized by blood-brain barrier dysfunction throughout the course of multiple sclerosis, followed by the entry of immune cells and activation of local microglia and astrocytes. Glial cells (microglia, astrocytes, and oligodendrocyte lineage cells) are known as the important mediators of neuroinflammation, all of which play major roles in the pathogenesis of multiple sclerosis. Network communications between glial cells affect the activities of oligodendrocyte lineage cells and influence the demyelination-remyelination process. A finely balanced glial response may create a favorable lesion environment for efficient remyelination and neuroregeneration. This review focuses on glial response and neurodegeneration based on the findings from multiple sclerosis and major rodent demyelination models. In particular, glial interaction and molecular crosstalk are discussed to provide insights into the potential cell- and molecule-specific therapeutic targets to improve remyelination and neuroregeneration.
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Affiliation(s)
- Tianci Chu
- Pediatric Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Lisa B.E. Shields
- Norton Neuroscience Institute, Norton Healthcare, Louisville, KY, USA
| | - Wenxin Zeng
- Pediatric Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Yi Ping Zhang
- Norton Neuroscience Institute, Norton Healthcare, Louisville, KY, USA
| | - Yuanyi Wang
- Department of Spine Surgery, The First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Gregory N. Barnes
- Pediatric Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
- Department of Neurology, University of Louisville School of Medicine, Louisville, KY, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
| | - Christopher B. Shields
- Norton Neuroscience Institute, Norton Healthcare, Louisville, KY, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, USA
| | - Jun Cai
- Pediatric Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
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5
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Adams KL, Dahl KD, Gallo V, Macklin WB. Intrinsic and extrinsic regulators of oligodendrocyte progenitor proliferation and differentiation. Semin Cell Dev Biol 2020; 116:16-24. [PMID: 34110985 DOI: 10.1016/j.semcdb.2020.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/14/2022]
Abstract
Oligodendrocytes are highly specialized glial cells, responsible for producing myelin in the central nervous system (CNS). The multi-stage process of oligodendrocyte development is tightly regulated to ensure proper lineage progression of oligodendrocyte progenitor cells (OPCs) to mature myelin producing oligodendrocytes. This developmental process involves complex interactions between several intrinsic signaling pathways that are modulated by an array of extrinsic factors. Understanding these regulatory processes is of crucial importance, as it may help to identify specific molecular targets both to enhance plasticity in the normal CNS and to promote endogenous recovery following injury or disease. This review describes two major regulators that play important functional roles in distinct phases of oligodendrocyte development: OPC proliferation and differentiation. Specifically, we highlight the roles of the extracellular astrocyte/radial glia-derived protein Endothelin-1 in OPC proliferation and the intracellular Akt/mTOR pathway in OPC differentiation. Lastly, we reflect on how recent advances in neuroscience and scientific technology will enable greater understanding into how intrinsic and extrinsic regulators interact to generate oligodendrocyte diversity.
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Affiliation(s)
- Katrina L Adams
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC 20010, USA
| | - Kristin D Dahl
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC 20010, USA
| | - Wendy B Macklin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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6
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Jiang Y, You M, Li S, Xu Y, Wang Y. Perinatal exposure to nonylphenol delayed myelination in offspring cerebellum. Biochem Pharmacol 2020; 178:114120. [PMID: 32589996 DOI: 10.1016/j.bcp.2020.114120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 06/11/2020] [Accepted: 06/19/2020] [Indexed: 01/06/2023]
Abstract
As a stable environmental contaminant, nonylphenol (NP) has been shown to induce some neurological deficits in the cerebellum, although the underlying mechanism is still unknown. In the present study, we aimed to investigate the effects of perinatal exposure to NP on myelination, an important process essential for the intact cerebellar function, in the offspring cerebellum. Exposure to NP delayed the myelination in the offspring cerebellum during perinatal period. The myelination recovered in the cerebellum of offspring exposed to NP over time, and returned to normal in adulthood. In addition, perinatal exposure to NP reduced mature oligodendrocytes (myelin-forming glial cells) and increased astrocytes in the offspring cerebellum. BMP signaling is believed to negatively regulate oligodendrogliogenesis and myelination. In the present study, BMP4, p-Smad1/5, and ID4, key members of BMP signaling, were increased in the cerebellum of offspring exposed to NP. Taken together, these lines of evidence suggest that the activation of BMP signaling may underlie the decreased oligodendrogliogenesis and increased astrogliogenesis, and the consequent delay of myelination in the cerebellum of offspring perinatally exposed to NP.
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Affiliation(s)
- Yuanjing Jiang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, PR China
| | - Mingdan You
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, PR China
| | - Siyao Li
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, PR China
| | - Yuanyuan Xu
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, PR China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, PR China.
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7
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Tognatta R, Karl MT, Fyffe-Maricich SL, Popratiloff A, Garrison ED, Schenck JK, Abu-Rub M, Miller RH. Astrocytes Are Required for Oligodendrocyte Survival and Maintenance of Myelin Compaction and Integrity. Front Cell Neurosci 2020; 14:74. [PMID: 32300294 PMCID: PMC7142332 DOI: 10.3389/fncel.2020.00074] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/12/2020] [Indexed: 12/16/2022] Open
Abstract
Astrocytes have been implicated in regulating oligodendrocyte development and myelination in vitro, although their functions in vivo remain less well defined. Using a novel approach to locally ablate GFAP+ astrocytes, we demonstrate that astrocytes are required for normal CNS myelin compaction during development, and for maintaining myelin integrity in the adult. Transient ablation of GFAP+ astrocytes in the mouse spinal cord during the first postnatal week reduced the numbers of mature oligodendrocytes and inhibited myelin formation, while prolonged ablation resulted in myelin that lacked compaction and structural integrity. Ablation of GFAP+ astrocytes in the adult spinal cord resulted in the rapid, local loss of myelin integrity and regional demyelination. The loss of myelin integrity induced by astrocyte ablation was greatly reduced by NMDA receptor antagonists, both in vitro and in vivo, suggesting that myelin stability was affected by elevation of local glutamate levels following astrocyte ablation. Furthermore, targeted delivery of glutamate into adult spinal cord white matter resulted in reduction of myelin basic protein expression and localized disruption of myelin compaction which was also reduced by NMDA receptor blockade. The pathology induced by localized astrocyte loss and elevated exogenous glutamate, supports the concept that astrocytes are critical for maintenance of myelin integrity in the adult CNS and may be primary targets in the initiation of demyelinating diseases of the CNS, such as Neuromyelitis Optica (NMO).
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Affiliation(s)
- Reshmi Tognatta
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States.,Gladstone Institute of Neurological Diseases, San Francisco, CA, United States
| | - Molly T Karl
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | | | - Anastas Popratiloff
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Eric D Garrison
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Jessica K Schenck
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Mohammad Abu-Rub
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Robert H Miller
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
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8
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Li MZ, Zhan Y, Yang L, Feng XF, Zou HY, Lei JF, Zhao T, Wang L, Zhao H. MRI Evaluation of Axonal Remodeling After Combination Treatment With Xiaoshuan Enteric-Coated Capsule and Enriched Environment in Rats After Ischemic Stroke. Front Physiol 2019; 10:1528. [PMID: 31920724 PMCID: PMC6930913 DOI: 10.3389/fphys.2019.01528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/04/2019] [Indexed: 12/24/2022] Open
Abstract
Xiaoshuan enteric-coated capsule (XSEC) is a compound Chinese medicine widely used for the treatment of ischemic stroke. Enriched environment (EE) is a rehabilitative intervention designed to facilitate physical, cognitive, and social activity after brain injury. This study aimed to assess whether the XSEC and EE combination could provide synergistic efficacy in axonal remodeling compared to that with a single treatment after ischemic stroke using magnetic resonance imaging (MRI) followed by histological analysis. Rats were subjected to permanent middle cerebral artery occlusion and treated with XSEC and EE alone or in combination for 30 days. T2-weighted imaging and diffusion tensor imaging (DTI) were performed to examine the infarct volume and axonal remodeling, respectively. The co-localization of Ki67 with NG2 or CNPase was examined by immunofluorescence staining to assess oligodendrogenesis. The expressions of growth associated protein-43 (GAP-43) and growth inhibitors NogoA/Nogo receptor (NgR)/RhoA/Rho-associated kinase2 (ROCK2) were measured using western blot and qRT-PCR. The Morris water maze (MWM) was performed to evaluate the cognitive function. MRI and histological measurements indicated XSEC and EE individually benefited axonal reorganization after stroke. Notably, XSEC + EE decreased infarct volume compared with XSEC or EE monotherapy and increased ipsilateral residual volume compared with vehicle group. DTI showed XSEC + EE robustly increased fractional anisotropy while decreased axial diffusivity and radial diffusivity in the injured cortex, striatum, and external capsule. Meanwhile, diffusion tensor tractography revealed XSEC + EE elevated fiber density in the cortex and external capsule and increased fiber length in the striatum and external capsule compared with the monotherapies. These MRI measurements, confirmed by histology, showed that XSEC + EE promoted axonal restoration. Additionally, XSEC + EE amplified oligodendrogenesis, decreased the expressions of NogoA/NgR/RhoA/ROCK2, and increased the expression of GAP-43 in the peri-infarct tissues. In parallel to these findings, rats treated with XSEC + EE exhibited higher cognitive recovery than those treated with XSEC or EE monotherapy, as evidenced by MWM test. Taken together, our data implicated that XSEC + EE exerted synergistic effects on alleviating atrophy and encouraging axonal reorganization partially by promoting oligodendrogenesis and overcoming intrinsic growth-inhibitory signaling, thereby facilitating higher cognitive recovery.
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Affiliation(s)
- Man-Zhong Li
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Yu Zhan
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Le Yang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Xue-Feng Feng
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Hai-Yan Zou
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Jian-Feng Lei
- Medical Imaging Laboratory of Core Facility Center, Capital Medical University, Beijing, China
| | - Ting Zhao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Lei Wang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
| | - Hui Zhao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.,Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing, China
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9
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Abstract
Leukodystrophies are genetically determined disorders affecting the white matter of the central nervous system. The combination of MRI pattern recognition and next-generation sequencing for the definition of novel disease entities has recently demonstrated that many leukodystrophies are due to the primary involvement and/or mutations in genes selectively expressed by cell types other than the oligodendrocytes, the myelin-forming cells in the brain. This has led to a new definition of leukodystrophies as genetic white matter disorders resulting from the involvement of any white matter structural component. As a result, the research has shifted its main focus from oligodendrocytes to other types of neuroglia. Astrocytes are the housekeeping cells of the nervous system, responsible for maintaining homeostasis and normal brain physiology and to orchestrate repair upon injury. Several lines of evidence show that astrocytic interactions with the other white matter cellular constituents play a primary pathophysiologic role in many leukodystrophies. These are thus now classified as astrocytopathies. This chapter addresses how the crosstalk between astrocytes, other glial cells, axons and non-neural cells are essential for the integrity and maintenance of the white matter in health. It also addresses the current knowledge of the cellular pathomechanisms of astrocytic leukodystrophies, and specifically Alexander disease, vanishing white matter, megalencephalic leukoencephalopathy with subcortical cysts and Aicardi-Goutière Syndrome.
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Affiliation(s)
- M S Jorge
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands.
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10
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What is the Functional Difference Between Sagittal With Metopic and Isolated Sagittal Craniosynotosis? J Craniofac Surg 2019; 30:968-973. [DOI: 10.1097/scs.0000000000005288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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11
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Inhibiting Bone Morphogenetic Protein 4 Type I Receptor Signaling Promotes Remyelination by Potentiating Oligodendrocyte Differentiation. eNeuro 2019; 6:ENEURO.0399-18.2019. [PMID: 31028086 PMCID: PMC6529590 DOI: 10.1523/eneuro.0399-18.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 03/31/2019] [Accepted: 04/18/2019] [Indexed: 12/22/2022] Open
Abstract
Blocking inhibitory factors within CNS demyelinating lesions is regarded as a promising strategy to promote remyelination. Bone morphogenetic protein 4 (BMP4) is an inhibitory factor present in demyelinating lesions. Noggin, an endogenous antagonist to BMP, has previously been shown to increase the number of oligodendrocytes and promote remyelination in vivo. However, it remains unclear how BMP4 signaling inhibits remyelination. Here we investigated the downstream signaling pathway that mediates the inhibitory effect that BMP4 exerts upon remyelination through pharmacological and transgenic approaches. Using the cuprizone mouse model of central demyelination, we demonstrate that selectively blocking BMP4 signaling via the pharmacological inhibitor LDN-193189 significantly promotes oligodendroglial differentiation and the extent of remyelination in vivo. This was accompanied by the downregulation of transcriptional targets that suppress oligodendrocyte differentiation. Further, selective deletion of BMP receptor type IA (BMPRIA) within primary mouse oligodendrocyte progenitor cells (OPCs) significantly enhanced their differentiation and subsequent myelination in vitro. Together, the results of this study identify that BMP4 signals via BMPRIA within OPCs to inhibit oligodendroglial differentiation and their capacity to myelinate axons, and suggest that blocking the BMP4/BMPRIA pathway in OPCs is a promising strategy to promote CNS remyelination.
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Harnisch K, Teuber-Hanselmann S, Macha N, Mairinger F, Fritsche L, Soub D, Meinl E, Junker A. Myelination in Multiple Sclerosis Lesions Is Associated with Regulation of Bone Morphogenetic Protein 4 and Its Antagonist Noggin. Int J Mol Sci 2019; 20:ijms20010154. [PMID: 30609838 PMCID: PMC6337410 DOI: 10.3390/ijms20010154] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/22/2018] [Accepted: 12/27/2018] [Indexed: 11/25/2022] Open
Abstract
Remyelination is a central aspect of new multiple sclerosis (MS) therapies, in which one aims to alleviate disease symptoms by improving axonal protection. However, a central problem is mediators expressed in MS lesions that prevent effective remyelination. Bone morphogenetic protein4 (BMP4) inhibits the development of mature oligodendrocytes in cell culture and also blocks the expression of myelin proteins. Additionally, numerous studies have shown that Noggin (SYM1)—among other physiological antagonists of BMP4—plays a prominent role in myelin formation in the developing but also the adult central nervous system. Nonetheless, neither BMP4 nor Noggin have been systematically studied in human MS lesions. In this study, we demonstrated by transcript analysis and immunohistochemistry that BMP4 is expressed by astrocytes and microglia/macrophages in association with inflammatory infiltrates in MS lesions, and that astrocytes also express BMP4 in chronic inactive lesions that failed to remyelinate. Furthermore, the demonstration of an increased expression of Noggin in so-called shadow plaques (i.e., remyelinated lesions with thinner myelin sheaths) in comparison to chronically inactive demyelinated lesions implies that antagonizing BMP4 is associated with successful remyelination in MS plaques in humans. However, although BMP4 is strongly overexpressed in inflammatory lesion areas, its levels are also elevated in remyelinated lesion areas, which raises the possibility that BMP4 signaling itself may be required for remyelination. Therefore, remyelination might be influenced by a small number of key factors. Manipulating these molecules, i.e., BMP4 and Noggin, could be a promising therapeutic approach for effective remyelination.
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Affiliation(s)
- Kim Harnisch
- Institute of Neuropathology, University Hospital Essen, D-45147 Essen, Germany.
| | | | - Nicole Macha
- Institute of Neuropathology, University Hospital Essen, D-45147 Essen, Germany.
| | - Fabian Mairinger
- Institute of Pathology, University Hospital Essen, D-45147 Essen, Germany.
| | - Lena Fritsche
- Institute of Neuropathology, University Hospital Essen, D-45147 Essen, Germany.
| | - Daniel Soub
- Institute of Neuropathology, University Hospital Essen, D-45147 Essen, Germany.
| | - Edgar Meinl
- Institute of Clinical Neuroimmunology, University Hospital and Biomedical Center, Ludwig-Maximilians-Universität München, D-82152 Martinsried, Germany.
| | - Andreas Junker
- Institute of Neuropathology, University Hospital Essen, D-45147 Essen, Germany.
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13
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Expression of Bone Morphogenetic Proteins in Multiple Sclerosis Lesions. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 189:665-676. [PMID: 30553833 DOI: 10.1016/j.ajpath.2018.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 01/17/2023]
Abstract
Bone morphogenetic proteins (BMPs) are secreted proteins that belong to the transforming growth factor-β superfamily. In the adult brain, they modulate neurogenesis, favor astrogliogenesis, and inhibit oligodendrogenesis. Because BMPs may be involved in the failure of remyelination in multiple sclerosis (MS), we characterized the expression of BMP-2, BMP-4, BMP-5, and BMP-7; BMP type II receptor (BMPRII); and phosphorylated SMAD (pSMAD) 1/5/8 in lesions of MS and other demyelinating diseases. A total of 42 MS lesions, 12 acute ischemic lesions, 8 progressive multifocal leukoencephalopathy lesions, and 10 central nervous system areas from four nonneuropathological patients were included. Lesions were histologically classified according to the inflammatory activity. The expression of BMP-2, BMP-4, BMP-5, BMP-7, BMPRII, and pSMAD1/5/8 was quantified by immunostaining, and colocalization studies were performed. In MS lesions, astrocytes, microglia/macrophages, and neurons expressed BMP-2, BMP-4, BMP-5, and BMP-7; BMPRII; and pSMAD1/5/8. Oligodendrocytes expressed BMP-2 and BMP-7 and pSMAD1/5/8. The percentage of cells that expressed BMPs, BMPRII, and pSMAD1/5/8 correlated with the inflammatory activity of MS lesions, and changes in the percentage of positive cells were more relevant in MS than in other white matter-damaging diseases. These data indicate that BMPs are increased in active MS lesions, suggesting a possible role in MS pathogenesis.
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14
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Dettman RW, Birch D, Fernando A, Kessler JA, Dizon ML. Targeted Knockdown of Bone Morphogenetic Protein Signaling within Neural Progenitors Protects the Brain and Improves Motor Function following Postnatal Hypoxia-Ischemia. Dev Neurosci 2018; 40:23-38. [PMID: 29324456 PMCID: PMC5861030 DOI: 10.1159/000485379] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 11/15/2017] [Indexed: 11/19/2022] Open
Abstract
Hypoxic-ischemic injury (HI) to the neonatal human brain results in myelin loss that, in some children, can manifest as cerebral palsy. Previously, we had found that neuronal overexpression of the bone morphogenic protein (BMP) inhibitor noggin during development increased oligodendroglia and improved motor function in an experimental model of HI utilizing unilateral common carotid artery ligation followed by hypoxia. As BMPs are known to negatively regulate oligodendroglial fate specification of neural stem cells and alter differentiation of committed oligodendroglia, BMP signaling is likely an important mechanism leading to myelin loss. Here, we showed that BMP signaling is upregulated within oligodendroglia of the neonatal brain. We tested the hypothesis that inhibition of BMP signaling specifically within neural progenitor cells (NPCs) is sufficient to protect oligodendroglia. We conditionally deleted the BMP receptor 2 subtype (BMPR2) in NG2-expressing cells after HI. We found that BMPR2 deletion globally protects the brain as assessed by MRI and protects motor function as assessed by digital gait analysis, and that conditional deletion of BMPR2 maintains oligodendrocyte marker expression by immunofluorescence and Western blot and prevents loss of oligodendroglia. Finally, BMPR2 deletion after HI results in an increase in noncompacted myelin. Thus, our data indicate that inhibition of BMP signaling specifically in NPCs may be a tractable strategy to protect the newborn brain from HI.
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Affiliation(s)
- Robert W. Dettman
- Developmental Biology Program, Stanley Manne Children’s Research Institute, Chicago, IL, USA
| | - Derin Birch
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Augusta Fernando
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - John A. Kessler
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Maria L.V. Dizon
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Kashima R, Hata A. The role of TGF-β superfamily signaling in neurological disorders. Acta Biochim Biophys Sin (Shanghai) 2018; 50:106-120. [PMID: 29190314 PMCID: PMC5846707 DOI: 10.1093/abbs/gmx124] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/02/2017] [Indexed: 12/12/2022] Open
Abstract
The TGF-β superfamily signaling is involved in a variety of biological processes during embryogenesis and in adult tissue homeostasis. Faulty regulation of the signaling pathway that transduces the TGF-β superfamily signals accordingly leads to a number of ailments, such as cancer and cardiovascular, metabolic, urinary, intestinal, skeletal, and immune diseases. In recent years, a number of studies have elucidated the essential roles of TGF-βs and BMPs during neuronal development in the maintenance of appropriate innervation and neuronal activity. The new advancement implicates significant roles of the aberrant TGF-β superfamily signaling in the pathogenesis of neurological disorders. In this review, we compile a number of reports implicating the deregulation of TGF-β/BMP signaling pathways in the pathogenesis of cognitive and neurodegenerative disorders in animal models and patients. We apologize in advance that the review falls short of providing details of the role of TGF-β/BMP signaling or mechanisms underlying the pathogenesis of neurological disorders. The goal of this article is to reveal a gap in our knowledge regarding the association between TGF-β/BMP signaling pathways and neuronal tissue homeostasis and development and facilitate the research with a potential to develop new therapies for neurological ailments by modulating the pathways.
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Affiliation(s)
- Risa Kashima
- Cardiovascular Research Institute, University of California, San Francisco, CA 94143, USA
| | - Akiko Hata
- Cardiovascular Research Institute, University of California, San Francisco, CA 94143, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
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Meyers EA, Kessler JA. TGF-β Family Signaling in Neural and Neuronal Differentiation, Development, and Function. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a022244. [PMID: 28130363 DOI: 10.1101/cshperspect.a022244] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Signaling by the transforming growth factor β (TGF-β) family is necessary for proper neural development and function throughout life. Sequential waves of activation, inhibition, and reactivation of TGF-β family members regulate numerous elements of the nervous system from the earliest stages of embryogenesis through adulthood. This review discusses the expression, regulation, and function of TGF-β family members in the central nervous system at various developmental stages, beginning with induction and patterning of the nervous system to their importance in the adult as modulators of inflammatory response and involvement in degenerative diseases.
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Affiliation(s)
- Emily A Meyers
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - John A Kessler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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17
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TLR4 Deficiency Impairs Oligodendrocyte Formation in the Injured Spinal Cord. J Neurosci 2017; 36:6352-64. [PMID: 27277810 DOI: 10.1523/jneurosci.0353-16.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Acute oligodendrocyte (OL) death after traumatic spinal cord injury (SCI) is followed by robust neuron-glial antigen 2 (NG2)-positive OL progenitor proliferation and differentiation into new OLs. Inflammatory mediators are prevalent during both phases and can influence the fate of NG2 cells and OLs. Specifically, toll-like receptor (TLR) 4 signaling induces OL genesis in the naive spinal cord, and lack of TLR4 signaling impairs white matter sparing and functional recovery after SCI. Therefore, we hypothesized that TLR4 signaling may regulate oligodendrogenesis after SCI. C3H/HeJ (TLR4-deficient) and control (C3H/HeOuJ) mice received a moderate midthoracic spinal contusion. TLR4-deficient mice showed worse functional recovery and reduced OL numbers compared with controls at 24 h after injury through chronic time points. Acute OL loss was accompanied by reduced ferritin expression, which is regulated by TLR4 and needed for effective iron storage. TLR4-deficient injured spinal cords also displayed features consistent with reduced OL genesis, including reduced NG2 expression, fewer BrdU-positive OLs, altered BMP4 signaling and inhibitor of differentiation 4 (ID4) expression, and delayed myelin phagocytosis. Expression of several factors, including IGF-1, FGF2, IL-1β, and PDGF-A, was altered in TLR4-deficient injured spinal cords compared with wild types. Together, these data show that TLR4 signaling after SCI is important for OL lineage cell sparing and replacement, as well as in regulating cytokine and growth factor expression. These results highlight new roles for TLR4 in endogenous SCI repair and emphasize that altering the function of a single immune-related receptor can dramatically change the reparative responses of multiple cellular constituents in the injured CNS milieu. SIGNIFICANCE STATEMENT Myelinating cells of the CNS [oligodendrocytes (OLs)] are killed for several weeks after traumatic spinal cord injury (SCI), but they are replaced by resident progenitor cells. How the concurrent inflammatory signaling affects this endogenous reparative response is unclear. Here, we provide evidence that immune receptor toll-like receptor 4 (TLR4) supports OL lineage cell sparing, long-term OL and OL progenitor replacement, and chronic functional recovery. We show that TLR4 signaling is essential for acute iron storage, regulating cytokine and growth factor expression, and efficient myelin debris clearance, all of which influence OL replacement. Importantly, the current study reveals that a single immune receptor is essential for repair responses after SCI, and the potential mechanisms of this beneficial effect likely change over time after injury.
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Uemura MT, Ihara M, Maki T, Nakagomi T, Kaji S, Uemura K, Matsuyama T, Kalaria RN, Kinoshita A, Takahashi R. Pericyte-derived bone morphogenetic protein 4 underlies white matter damage after chronic hypoperfusion. Brain Pathol 2017; 28:521-535. [PMID: 28470822 PMCID: PMC6099372 DOI: 10.1111/bpa.12523] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 04/18/2017] [Indexed: 01/03/2023] Open
Abstract
Subcortical small vessel disease (SVD) is characterized by white matter damage resulting from arteriolosclerosis and chronic hypoperfusion. Transforming growth factor beta 1 (TGFB1) is dysregulated in the hereditary SVD, CARASIL (cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy). However, very little is known about the role of the largest group in the TGFB superfamily - the bone morphogenetic proteins (BMPs) - in SVD pathogenesis. The aim of this study was to characterize signaling abnormalities of BMPs in sporadic SVD. We examined immunostaining of TGFB1 and BMPs (BMP2/BMP4/BMP6/BMP7/BMP9) in a total of 19 post-mortem human brain samples as follows: 7 SVD patients (4 males, 76-90 years old); 6 Alzheimer's disease (AD) patients (2 males, 67-93 years old) and 6 age-matched disease controls (3 males, 68-78 years old). We subsequently investigated the effects of oxygen-glucose deprivation and BMP4 addition on cultured cells. Furthermore, adult mice were subjected to chronic cerebral hypoperfusion using bilateral common carotid artery stenosis, followed by continuous intracerebroventricular infusion of the BMP antagonist, noggin. In the SVD cases, BMP4 was highly expressed in white matter pericytes. Oxygen-glucose deprivation induced BMP4 expression in cultured pericytes in vitro. Recombinant BMP4 increased the number of cultured endothelial cells and pericytes and converted oligodendrocyte precursor cells into astrocytes. Chronic cerebral hypoperfusion in vivo also upregulated BMP4 with concomitant white matter astrogliogenesis and reduced oligodendrocyte lineage cells, both of which were suppressed by intracerebroventricular noggin infusion. Our findings suggest ischemic white matter damage evolves in parallel with BMP4 upregulation in pericytes. BMP4 promotes angiogenesis, but induces astrogliogenesis at the expense of oligodendrocyte precursor cell proliferation and maturation, thereby aggravating white matter damage. This may explain white matter vulnerability to chronic hypoperfusion. The regulation of BMP4 signaling is a potential therapeutic strategy for treating SVD.
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Affiliation(s)
- Maiko T Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masafumi Ihara
- Department of Neurology, National Cerebral and Cardiovascular Center Hospital, Osaka, Japan
| | - Takakuni Maki
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takayuki Nakagomi
- Institute for Advanced Medical Sciences, Hyogo College of Medicine, Hyogo, Japan
| | - Seiji Kaji
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kengo Uemura
- Department of Neurology, Ishiki Hospital, Kagoshima, Japan
| | - Tomohiro Matsuyama
- Institute for Advanced Medical Sciences, Hyogo College of Medicine, Hyogo, Japan
| | - Raj N Kalaria
- Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Ayae Kinoshita
- School of Human Health Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Wang X, Xu J, Wang Y, Yang L, Li Z. Protective effects of BMP‐7 against tumor necrosis factor α‐induced oligodendrocyte apoptosis. Int J Dev Neurosci 2016; 53:10-17. [DOI: 10.1016/j.ijdevneu.2016.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 12/25/2022] Open
Affiliation(s)
- Xin Wang
- Department of AnesthesiologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
- Anesthesia Research InstituteCentral South UniversityChangshaHunanChina
| | - Jun‐Mei Xu
- Department of AnesthesiologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
- Anesthesia Research InstituteCentral South UniversityChangshaHunanChina
| | - Ya‐Ping Wang
- Department of AnesthesiologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
- Anesthesia Research InstituteCentral South UniversityChangshaHunanChina
| | - Lin Yang
- Department of AnesthesiologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
- Anesthesia Research InstituteCentral South UniversityChangshaHunanChina
| | - Zhi‐Jian Li
- Department of AnesthesiologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
- Anesthesia Research InstituteCentral South UniversityChangshaHunanChina
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20
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Cole AE, Murray SS, Xiao J. Bone Morphogenetic Protein 4 Signalling in Neural Stem and Progenitor Cells during Development and after Injury. Stem Cells Int 2016; 2016:9260592. [PMID: 27293450 PMCID: PMC4884839 DOI: 10.1155/2016/9260592] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/19/2016] [Accepted: 04/26/2016] [Indexed: 01/17/2023] Open
Abstract
Substantial progress has been made in identifying the extracellular signalling pathways that regulate neural stem and precursor cell biology in the central nervous system (CNS). The bone morphogenetic proteins (BMPs), in particular BMP4, are key players regulating neuronal and glial cell development from neural precursor cells in the embryonic, postnatal, and injured CNS. Here we review recent studies on BMP4 signalling in the generation of neurons, astrocytes, and oligodendroglial cells in the CNS. We also discuss putative mechanisms that BMP4 may utilise to influence glial cell development following CNS injury and highlight some questions for further research.
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Affiliation(s)
- Alistair E. Cole
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Simon S. Murray
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
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21
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Abstract
Oligodendrocyte precursor cells (OPCs) originate in the ventricular zones (VZs) of the brain and spinal cord and migrate throughout the developing central nervous system (CNS) before differentiating into myelinating oligodendrocytes (OLs). It is not known whether OPCs or OLs from different parts of the VZ are functionally distinct. OPCs persist in the postnatal CNS, where they continue to divide and generate myelinating OLs at a decreasing rate throughout adult life in rodents. Adult OPCs respond to injury or disease by accelerating their cell cycle and increasing production of OLs to replace lost myelin. They also form synapses with unmyelinated axons and respond to electrical activity in those axons by generating more OLs and myelin locally. This experience-dependent "adaptive" myelination is important in some forms of plasticity and learning, for example, motor learning. We review the control of OL lineage development, including OL population dynamics and adaptive myelination in the adult CNS.
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Affiliation(s)
- Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, WBSB 1001, Baltimore, Maryland 21205
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
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22
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Intracellular Protein Shuttling: A Mechanism Relevant for Myelin Repair in Multiple Sclerosis? Int J Mol Sci 2015; 16:15057-85. [PMID: 26151843 PMCID: PMC4519887 DOI: 10.3390/ijms160715057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 12/15/2022] Open
Abstract
A prominent feature of demyelinating diseases such as multiple sclerosis (MS) is the degeneration and loss of previously established functional myelin sheaths, which results in impaired signal propagation and axonal damage. However, at least in early disease stages, partial replacement of lost oligodendrocytes and thus remyelination occur as a result of resident oligodendroglial precursor cell (OPC) activation. These cells represent a widespread cell population within the adult central nervous system (CNS) that can differentiate into functional myelinating glial cells to restore axonal functions. Nevertheless, the spontaneous remyelination capacity in the adult CNS is inefficient because OPCs often fail to generate new oligodendrocytes due to the lack of stimulatory cues and the presence of inhibitory factors. Recent studies have provided evidence that regulated intracellular protein shuttling is functionally involved in oligodendroglial differentiation and remyelination activities. In this review we shed light on the role of the subcellular localization of differentiation-associated factors within oligodendroglial cells and show that regulation of intracellular localization of regulatory factors represents a crucial process to modulate oligodendroglial maturation and myelin repair in the CNS.
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23
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Shi H, Hu X, Leak RK, Shi Y, An C, Suenaga J, Chen J, Gao Y. Demyelination as a rational therapeutic target for ischemic or traumatic brain injury. Exp Neurol 2015; 272:17-25. [PMID: 25819104 DOI: 10.1016/j.expneurol.2015.03.017] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/15/2015] [Accepted: 03/18/2015] [Indexed: 12/11/2022]
Abstract
Previous research on stroke and traumatic brain injury (TBI) heavily emphasized pathological alterations in neuronal cells within gray matter. However, recent studies have highlighted the equal importance of white matter integrity in long-term recovery from these conditions. Demyelination is a major component of white matter injury and is characterized by loss of the myelin sheath and oligodendrocyte cell death. Demyelination contributes significantly to long-term sensorimotor and cognitive deficits because the adult brain only has limited capacity for oligodendrocyte regeneration and axonal remyelination. In the current review, we will provide an overview of the major causes of demyelination and oligodendrocyte cell death following acute brain injuries, and discuss the crosstalk between myelin, axons, microglia, and astrocytes during the process of demyelination. Recent discoveries of molecules that regulate the processes of remyelination may provide novel therapeutic targets to restore white matter integrity and improve long-term neurological recovery in stroke or TBI patients.
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Affiliation(s)
- Hong Shi
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Department of Anesthesiology of Shanghai Pulmonary Hospital, Tongji University, Shanghai 200433, China
| | - Xiaoming Hu
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Yejie Shi
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA
| | - Chengrui An
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Jun Suenaga
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jun Chen
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA.
| | - Yanqin Gao
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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24
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Gallo V, Deneen B. Glial development: the crossroads of regeneration and repair in the CNS. Neuron 2014; 83:283-308. [PMID: 25033178 DOI: 10.1016/j.neuron.2014.06.010] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 02/07/2023]
Abstract
Given the complexities of the mammalian CNS, its regeneration is viewed as the holy grail of regenerative medicine. Extraordinary efforts have been made to understand developmental neurogenesis, with the hopes of clinically applying this knowledge. CNS regeneration also involves glia, which comprises at least 50% of the cellular constituency of the brain and is involved in all forms of injury and disease response, recovery, and regeneration. Recent developmental studies have given us unprecedented insight into the processes that regulate the generation of CNS glia. Because restorative processes often parallel those found in development, we will peer through the lens of developmental gliogenesis to gain a clearer understanding of the processes that underlie glial regeneration under pathological conditions. Specifically, this review will focus on key signaling pathways that regulate astrocyte and oligodendrocyte development and describe how these mechanisms are reutilized in these populations during regeneration and repair after CNS injury.
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Affiliation(s)
- Vittorio Gallo
- Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, USA.
| | - Benjamin Deneen
- Department of Neuroscience and Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA.
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25
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El Waly B, Macchi M, Cayre M, Durbec P. Oligodendrogenesis in the normal and pathological central nervous system. Front Neurosci 2014; 8:145. [PMID: 24971048 PMCID: PMC4054666 DOI: 10.3389/fnins.2014.00145] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/23/2014] [Indexed: 12/26/2022] Open
Abstract
Oligodendrocytes (OLGs) are generated late in development and myelination is thus a tardive event in the brain developmental process. It is however maintained whole life long at lower rate, and myelin sheath is crucial for proper signal transmission and neuronal survival. Unfortunately, OLGs present a high susceptibility to oxidative stress, thus demyelination often takes place secondary to diverse brain lesions or pathologies. OLGs can also be the target of immune attacks, leading to primary demyelination lesions. Following oligodendrocytic death, spontaneous remyelination may occur to a certain extent. In this review, we will mainly focus on the adult brain and on the two main sources of progenitor cells that contribute to oligodendrogenesis: parenchymal oligodendrocyte precursor cells (OPCs) and subventricular zone (SVZ)-derived progenitors. We will shortly come back on the main steps of oligodendrogenesis in the postnatal and adult brain, and summarize the key factors involved in the determination of oligodendrocytic fate. We will then shed light on the main causes of demyelination in the adult brain and present the animal models that have been developed to get insight on the demyelination/remyelination process. Finally, we will synthetize the results of studies searching for factors able to modulate spontaneous myelin repair.
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Affiliation(s)
- Bilal El Waly
- CNRS, Institut de Biologie du Développement de Marseille UMR 7288, Aix Marseille Université Marseille, France
| | - Magali Macchi
- CNRS, Institut de Biologie du Développement de Marseille UMR 7288, Aix Marseille Université Marseille, France
| | - Myriam Cayre
- CNRS, Institut de Biologie du Développement de Marseille UMR 7288, Aix Marseille Université Marseille, France
| | - Pascale Durbec
- CNRS, Institut de Biologie du Développement de Marseille UMR 7288, Aix Marseille Université Marseille, France
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26
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Back SA, Miller SP. Brain injury in premature neonates: A primary cerebral dysmaturation disorder? Ann Neurol 2014; 75:469-86. [PMID: 24615937 PMCID: PMC5989572 DOI: 10.1002/ana.24132] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 12/11/2022]
Abstract
With advances in neonatal care, preterm neonates are surviving with an evolving constellation of motor and cognitive disabilities that appear to be related to widespread cellular maturational disturbances that target cerebral gray and white matter. Whereas preterm infants were previously at high risk for destructive brain lesions that resulted in cystic white matter injury and secondary cortical and subcortical gray matter degeneration, contemporary cohorts of preterm survivors commonly display less severe injury that does not appear to involve pronounced glial or neuronal loss. Nevertheless, these milder forms of injury are also associated with reduced cerebral growth. Recent human and experimental studies support that impaired cerebral growth is related to disparate responses in gray and white matter. Myelination disturbances in cerebral white matter are related to aberrant regeneration and repair responses to acute death of premyelinating late oligodendrocyte progenitors (preOLs). In response to preOL death, early oligodendrocyte progenitors rapidly proliferate and differentiate, but the regenerated preOLs fail to normally mature to myelinating cells required for white matter growth. Although immature neurons appear to be more resistant to cell death from hypoxia-ischemia than glia, they display widespread disturbances in maturation of their dendritic arbors, which further contribute to impaired cerebral growth. These complex and disparate responses of neurons and preOLs thus result in large numbers of cells that fail to fully mature during a critical window in development of neural circuitry. These recently recognized forms of cerebral gray and white matter dysmaturation raise new diagnostic challenges and suggest new therapeutic directions centered on reversal of the processes that promote dysmaturation.
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Affiliation(s)
- Stephen A Back
- Departments of Pediatrics, Oregon Health and Science University, Portland; Departments of Neurology, Oregon Health and Science University, Portland
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27
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Back SA, Rosenberg PA. Pathophysiology of glia in perinatal white matter injury. Glia 2014; 62:1790-815. [PMID: 24687630 DOI: 10.1002/glia.22658] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/13/2014] [Accepted: 02/27/2014] [Indexed: 12/12/2022]
Abstract
Injury to the preterm brain has a particular predilection for cerebral white matter. White matter injury (WMI) is the most common cause of brain injury in preterm infants and a major cause of chronic neurological morbidity including cerebral palsy. Factors that predispose to WMI include cerebral oxygenation disturbances and maternal-fetal infection. During the acute phase of WMI, pronounced oxidative damage occurs that targets late oligodendrocyte progenitors (pre-OLs). The developmental predilection for WMI to occur during prematurity appears to be related to both the timing of appearance and regional distribution of susceptible pre-OLs that are vulnerable to a variety of chemical mediators including reactive oxygen species, glutamate, cytokines, and adenosine. During the chronic phase of WMI, the white matter displays abberant regeneration and repair responses. Early OL progenitors respond to WMI with a rapid robust proliferative response that results in a several fold regeneration of pre-OLs that fail to terminally differentiate along their normal developmental time course. Pre-OL maturation arrest appears to be related in part to inhibitory factors that derive from reactive astrocytes in chronic lesions. Recent high field magnetic resonance imaging (MRI) data support that three distinct forms of chronic WMI exist, each of which displays unique MRI and histopathological features. These findings suggest the possibility that therapies directed at myelin regeneration and repair could be initiated early after WMI and monitored over time. These new mechanisms of acute and chronic WMI provide access to a variety of new strategies to prevent or promote repair of WMI in premature infants.
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Affiliation(s)
- Stephen A Back
- Department of Pediatrics, Oregon Health and Science University, Portland, Oregon; Department of Neurology, Oregon Health and Science University, Portland, Oregon
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Clemente D, Ortega MC, Melero-Jerez C, de Castro F. The effect of glia-glia interactions on oligodendrocyte precursor cell biology during development and in demyelinating diseases. Front Cell Neurosci 2013; 7:268. [PMID: 24391545 PMCID: PMC3868919 DOI: 10.3389/fncel.2013.00268] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 12/03/2013] [Indexed: 01/12/2023] Open
Abstract
Oligodendrocyte precursor cells (OPCs) originate in specific areas of the developing central nervous system (CNS). Once generated, they migrate towards their destinations where they differentiate into mature oligodendrocytes. In the adult, 5-8% of all cells in the CNS are OPCs, cells that retain the capacity to proliferate, migrate, and differentiate into oligodendrocytes. Indeed, these endogenous OPCs react to damage in demyelinating diseases, like multiple sclerosis (MS), representing a key element in spontaneous remyelination. In the present work, we review the specific interactions between OPCs and other glial cells (astrocytes, microglia) during CNS development and in the pathological scenario of MS. We focus on: (i) the role of astrocytes in maintaining the homeostasis and spatial distribution of different secreted cues that determine OPC proliferation, migration, and differentiation during CNS development; (ii) the role of microglia and astrocytes in the redistribution of iron, which is crucial for myelin synthesis during CNS development and for myelin repair in MS; (iii) how microglia secrete different molecules, e.g., growth factors, that favor the recruitment of OPCs in acute phases of MS lesions; and (iv) how astrocytes modify the extracellular matrix in MS lesions, affecting the ability of OPCs to attempt spontaneous remyelination. Together, these issues demonstrate how both astroglia and microglia influence OPCs in physiological and pathological situations, reinforcing the concept that both development and neural repair are complex and global phenomena. Understanding the molecular and cellular mechanisms that control OPC survival, proliferation, migration, and differentiation during development, as well as in the mature CNS, may open new opportunities in the search for reparative therapies in demyelinating diseases like MS.
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Affiliation(s)
- Diego Clemente
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - María Cristina Ortega
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - Carolina Melero-Jerez
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
| | - Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos Toledo, Spain
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Wnt signaling in remyelination in multiple sclerosis: friend or foe? Mol Neurobiol 2013; 49:1117-25. [PMID: 24243343 DOI: 10.1007/s12035-013-8584-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/01/2013] [Indexed: 12/22/2022]
Abstract
Myelination is critical to normal functioning of the vertebrate nervous system. In demyelinating diseases such as multiple sclerosis, oligodendrocytes, the myelinating cells in the central nervous system, are targeted, resulting in myelin loss, axonal damage, and severe functional impairment. While spontaneous remyelination has been proven a failure in multiple sclerosis, understanding the molecular mechanism underlying oligodendrocyte biology, myelination, and remyelination becomes crucial. To date, a series of signaling pathways in regulating oligodendrocyte development and remyelination have been suggested and, among them, the Wnt/β-catenin/Tcf pathway has been considered a negative factor in the myelinating process. However, this notion has been challenged by recent studies, which showed a pro-myelinating effect of this pathway. This review summarizes the current contradictory concepts concerning the role of the Wnt pathway in the oligodendrocyte development and remyelination process, attempts to address the potential mechanism underlying this controversy, and recommends caution in targeting the Wnt pathway as a potential demyelinating therapy.
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30
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Bone morphogenetic proteins prevent bone marrow stromal cell-mediated oligodendroglial differentiation of transplanted adult neural progenitor cells in the injured spinal cord. Stem Cell Res 2013; 11:758-71. [DOI: 10.1016/j.scr.2013.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 05/02/2013] [Accepted: 05/08/2013] [Indexed: 01/01/2023] Open
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31
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Gámez B, Rodriguez-Carballo E, Ventura F. BMP signaling in telencephalic neural cell specification and maturation. Front Cell Neurosci 2013; 7:87. [PMID: 23761735 PMCID: PMC3671186 DOI: 10.3389/fncel.2013.00087] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) make up a family of morphogens that are critical for patterning, development, and function of the central and peripheral nervous system. Their effects on neural cells are pleiotropic and highly dynamic depending on the stage of development and the local niche. Neural cells display a broad expression profile of BMP ligands, receptors, and transducer molecules. Moreover, interactions of BMP signaling with other incoming morphogens and signaling pathways are crucial for most of these processes. The key role of BMP signaling suggests that it includes many regulatory mechanisms that restrict BMP activity both temporally and spatially. BMPs affect neural cell fate specification in a dynamic fashion. Initially they inhibit proliferation of neural precursors and promote the first steps in neuronal differentiation. Later on, BMP signaling effects switch from neuronal induction to promotion of astroglial identity and inhibition of neuronal or oligodendroglial lineage commitment. Furthermore, in postmitotic cells, BMPs regulate cell survival and death, to modulate neuronal subtype specification, promote dendritic and axonal growth and induce synapse formation and stabilization. In this review, we examine the canonical and non-canonical mechanisms of BMP signal transduction. Moreover, we focus on the specific role of BMPs in the nervous system including their ability to regulate neural stem cell proliferation, self-renewal, lineage specification, and neuronal function.
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Affiliation(s)
- Beatriz Gámez
- Departament de Ciències Fisiològiques II, Institut d'Investigació Biomèdica de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat Spain
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32
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Abstract
Astrocytes are the most abundant cell type in the adult central nervous system (CNS), and their functional diversity in response to injury is now being appreciated. Astrocytes have long been considered the main player in the inhibition of CNS repair via the formation of the gliotic scar, but now it is accepted that astrocyte can play an important role in CNS repair and remyelination. Interest in the relationship between astrocytes and myelination focused initially on attempts to understand how the development of plaques of astroglial scar tissue in multiple sclerosis was related to the failure of these lesions to remyelinate. It is now considered that this is an end stage pathological response to injury, and that normally astrocytes play important roles in supporting the development and maintenance of CNS myelin. This review will focus on how this new understanding may be exploited to develop new strategies to enhance remyelination in multiple sclerosis and other diseases.
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Affiliation(s)
- Susan C Barnett
- Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, UK.
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33
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Chen LP, Li ZF, Ping M, Li R, Liu J, Xie XH, Song XJ, Guo L. Regulation of Olig2 during astroglial differentiation in the subventricular zone of a cuprizone-induced demyelination mouse model. Neuroscience 2012; 221:96-107. [PMID: 22771621 DOI: 10.1016/j.neuroscience.2012.06.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 05/18/2012] [Accepted: 06/23/2012] [Indexed: 10/28/2022]
Abstract
The mammalian subventricular zone (SVZ) is the largest germinative zone of the adult brain. Progenitor cells generated from the SVZ play important roles during the remyelination process. To determine the functional role of Olig2 in regulating astroglial differentiation in the mouse SVZ, we used the cuprizone mouse model to investigate demyelination. We found that cuprizone administration significantly enhanced the expression of Olig2 and increased astroglial differentiation in the SVZ, as compared with control. Moreover, cytoplasmic translocation of Olig2 occurred after demyelination. In vitro studies further revealed that supplementation of culture media with growth factors enhanced the oligodendroglial differentiation of oligodendrocyte progenitor cells (OPCs), whereas serum alone promoted astroglial differentiation and cytoplasmic translocation of Olig2. Additionally, the expression levels of bone morphogenetic proteins 2 and 4 (BMP2 and BMP4) and inhibitor of DNA binding 2 and 4 (Id2 and Id4) were greatly elevated during astroglial differentiation. BMP inhibition by noggin suppressed the astroglial differentiation of OPCs. Our results indicate that Olig2 may serve as a key regulator during the directional differentiation of progenitor cells after demyelination. The BMP signaling pathway may contribute to the cytoplasmic translocation and altered expression of Olig2 during the remyelination process. These findings provide a better understanding of the mechanisms involved in remyelination.
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Affiliation(s)
- L P Chen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, People's Republic of China
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34
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Webb TR, Matarin M, Gardner JC, Kelberman D, Hassan H, Ang W, Michaelides M, Ruddle JB, Pennell CE, Yazar S, Khor CC, Aung T, Yogarajah M, Robson AG, Holder GE, Cheetham ME, Traboulsi EI, Moore AT, Sowden JC, Sisodiya SM, Mackey DA, Tuft SJ, Hardcastle AJ. X-linked megalocornea caused by mutations in CHRDL1 identifies an essential role for ventroptin in anterior segment development. Am J Hum Genet 2012; 90:247-59. [PMID: 22284829 DOI: 10.1016/j.ajhg.2011.12.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/07/2011] [Accepted: 12/26/2011] [Indexed: 01/30/2023] Open
Abstract
X-linked megalocornea (MGC1) is an ocular anterior segment disorder characterized by an increased cornea diameter and deep anterior chamber evident at birth and later onset of mosaic corneal degeneration (shagreen), arcus juvenilis, and presenile cataracts. We identified copy-number variation, frameshift, missense, splice-site and nonsense mutations in the Chordin-like 1 gene (CHRDL1) on Xq23 as the cause of the condition in seven MGC1 families. CHRDL1 encodes ventroptin, a bone morphogenic protein antagonist with a proposed role in specification of topographic retinotectal projections. Electrophysiological evaluation revealed mild generalized cone system dysfunction and, in one patient, an interhemispheric asymmetry in visual evoked potentials. We show that CHRDL1 is expressed in the developing human cornea and anterior segment in addition to the retina. We explored the impact of loss of ventroptin function on brain function and morphology in vivo. CHRDL1 is differentially expressed in the human fetal brain, and there is high expression in cerebellum and neocortex. We show that MGC1 patients have a superior cognitive ability despite a striking focal loss of myelination of white matter. Our findings reveal an unexpected requirement for ventroptin during anterior segment development and the consequences of a lack of function in the retina and brain.
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Affiliation(s)
- Tom R Webb
- Institute of Ophthalmology, University College London, UK
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35
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Moore CS, Abdullah SL, Brown A, Arulpragasam A, Crocker SJ. How factors secreted from astrocytes impact myelin repair. J Neurosci Res 2011; 89:13-21. [PMID: 20857501 DOI: 10.1002/jnr.22482] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/10/2010] [Accepted: 06/24/2010] [Indexed: 12/12/2022]
Abstract
Over a century ago, hypertrophy of astrocytes was noted as a pathology of multiple sclerosis (MS) and was hypothesized to play an important role in this disease, yet the contribution of astrocytes has been largely underemphasized in the pathophysiology of CNS demyelination. Astrocytes perform many homeostatic functions within the developing and adult CNS, including enhancing formation and maintenance of the blood-brain barrier, moderating neuronal connections through the tripartite synapse, and perhaps even offering intercellular communication independently of neurons. Although there is a significant body of literature characterizing different types of MS lesions, the inflammatory demyelination in an active MS lesion is accompanied by the presence of macrophages, lymphocytes, and large reactive astrocytes. The astrocyte has long been viewed as a cell that promotes inflammation and demyelination, while also forming the glial scar, thus hindering remyelination and axon growth. Renewed interest in the astrocyte has been brought about by recent studies demonstrating that astrocytes can also function as cellular mediators of CNS myelination by promoting oligodendrocyte progenitor migration, proliferation, and differentiation. Thus, refining our knowledge of astrocytic functions in the regulation of CNS myelination may help us to better understand why remyelination fails in MS.
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Affiliation(s)
- Craig S Moore
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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Voumvourakis KI, Antonelou RC, Kitsos DK, Stamboulis E, Tsiodras S. TGF-β/BMPs: crucial crossroad in neural autoimmune disorders. Neurochem Int 2011; 59:542-50. [PMID: 21718734 DOI: 10.1016/j.neuint.2011.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 05/15/2011] [Accepted: 06/05/2011] [Indexed: 01/12/2023]
Abstract
Transforming growth factor beta (TGF-β) has a crucial role in the differentiation of ectodermal cells to neural or epidermal precursors. TGF-β and bone morphogenetic protein molecules (BMPs) are involved in many developmental processes, including cell proliferation and differentiation, apoptosis, mitotic arrest and intercellular interactions during morphogenesis. Additionally, the failure of central thymic tolerance mechanisms, leading to T cells with a skewed autoreactive response, is being described as a contributor in inflammatory processes in autoimmune diseases such as multiple sclerosis. Since TGF-β and BMP proteins are crucial for the development of the neural system and the thymus, as well as for the differentiation of T cells, it is essential to further investigate their role in the pathophysiology of this disorder by using references from embryonic experimental research. Available literature in the TGF/BMP signalling cascade, mostly during embryonic development of the nervous system is being reviewed. An attempt is made to further elucidate a potential role of TGF/BMP signalling in the pathophysiology of MS. During demyelination, BMP signaling, through various molecular mechanisms, directs the development of the adult neural stem cell in the astrocyte rather than the oligodendrocyte direction, therefore inhibiting the repair process. Further understanding of the above relationships could lead to the development of potentially efficient therapies for MS in the future.
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Affiliation(s)
- Konstantine I Voumvourakis
- 2nd Department of Neurology, Attikon University Hospital, University of Athens Medical School, Athens, Greece
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37
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Abstract
OLs (oligodendrocytes) are the myelinating cells of the CNS (central nervous system), wrapping axons in conductive sheathes to ensure effective transmission of neural signals. The regulation of OL development, from precursor to mature myelinating cell, is controlled by a variety of inhibitory and inductive signalling factors. The dorsal spinal cord contains signals that inhibit OL development, possibly to prevent premature and ectopic precursor differentiation. The Wnt and BMP (bone morphogenic protein) signalling pathways have been identified as dorsal spinal cord signals with overlapping temporal activity, and both have similar inhibitory effects on OL differentiation. Both these pathways feature prominently in many developmental processes and demyelinating events after injury, and they are known to interact in complex inductive, inhibitive and synergistic manners in many developing systems. The interaction between BMP and Wnt signalling in OL development, however, has not been extensively explored. In the present study, we examine the relationship between the canonical Wnt and BMP pathways. We use pharmacological and genetic paradigms to show that both Wnt3a and BMP4 will inhibit OL differentiation in vitro. We also show that when the canonical BMP signalling pathway is blocked, neither Wnt3a nor BMP4 have inhibitory effects on OL differentiation. In contrast, abrogating the Wnt signalling pathway does not alter the actions of BMP4 treatment. Our results indicate that the BMP signalling pathway is necessary for the canonical Wnt signalling pathway to exert its effects on OL development, but not vice versa, suggesting that Wnt signals upstream of BMP.
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38
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Abstract
Extensive literature documented that astrocytes release neurotransmitters, cytokines and other signaling molecules to modulate migration, maturation and myelin synthesis of oligodendrocytes through mechanisms primarily converging on cytosolic [Ca2+] transients. Considering the long-term effects, it is expected that astrocyte-conditioned medium is a major regulator of gene expression in oligodendrocytes even in the absence of cytosol-to-cytosol communication via astrocyte-oligodendrocyte gap junction channels. Indeed, by comparing the transcriptomes of immortalized precursor oligodendrocyte (Oli-neu) cells when cultured alone and co-cultured with non-touching astrocytes we found profound changes in the gene expression level, control and networking. Remarkably, the astrocyte proximity was more effective in remodeling the myelination (MYE) gene fabric and its control by cytokine receptor (CYR)-modulated intercellular Ca2+-signaling (ICS) transcriptomic network than the dibutyryl-cAMP (db-cAMP) treatment-induced transformation into myelin-associated glycoprotein-positive oligodendrocyte-like cells. Moreover, astrocyte proximity up-regulated 37 MYE genes and switched on another 14 MYE, 23 ICS and 4 CYR genes, enhancing the roles of the leukemia inhibitory factor receptor and connexins Cx29 and Cx47. The novel prominent gene analysis identified the enhancer of zeste homolog 2 as the most relevant MYE gene in the astrocyte proximity, notch gene homolog 1 in control and B-cell leukemia/lymphoma 2 in differentiated Oli-neu cells.
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39
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Chordin-induced lineage plasticity of adult SVZ neuroblasts after demyelination. Nat Neurosci 2010; 13:541-550. [PMID: 20418875 DOI: 10.1038/nn.2536] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 03/25/2010] [Indexed: 12/14/2022]
Abstract
The mechanisms that regulate the developmental potential of adult neural progenitor populations under physiological and pathological conditions remain poorly defined. Glutamic acid decarboxylase 65 (GAD65)- and Doublecortin (Dcx)-expressing cells constitute major progenitor populations in the adult mouse subventricular zone (SVZ). Under normal physiological conditions, SVZ-derived GAD65-positive and Dcx-positive cells expressed the transcription factor Pax6 and migrated along the rostral migratory stream to the olfactory bulb to generate interneurons. After lysolecithin-induced demyelination of corpus callosum, however, these cells altered their molecular and cellular properties and migratory path. Demyelination upregulated chordin in the SVZ, which redirected GAD65-positive and Dcx-positive progenitors from neuronal to glial fates, generating new oligodendrocytes in the corpus callosum. Our findings suggest that the lineage plasticity of SVZ progenitor cells could be a potential therapeutic strategy for diseased or injured brain.
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40
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Regulation of oligodendrocyte progenitor cell maturation by PPARδ: effects on bone morphogenetic proteins. ASN Neuro 2010; 2:e00025. [PMID: 20001953 PMCID: PMC2807733 DOI: 10.1042/an20090033] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 12/22/2022] Open
Abstract
In EAE (experimental autoimmune encephalomyelitis), agonists of PPARs (peroxisome proliferator-activated receptors) provide clinical benefit and reduce damage. In contrast with PPARγ, agonists of PPARδ are more effective when given at later stages of EAE and increase myelin gene expression, suggesting effects on OL (oligodendrocyte) maturation. In the present study we examined effects of the PPARδ agonist GW0742 on OPCs (OL progenitor cells), and tested whether the effects involve modulation of BMPs (bone morphogenetic proteins). We show that effects of GW0742 are mediated through PPARδ since no amelioration of EAE clinical scores was observed in PPARδ-null mice. In OPCs derived from E13 mice (where E is embryonic day), GW0742, but not the PPARγ agonist pioglitazone, increased the number of myelin-producing OLs. This was due to activation of PPARδ since process formation was reduced in PPARδ-null compared with wild-type OPCs. In both OPCs and enriched astrocyte cultures, GW0742 increased noggin protein expression; however, noggin mRNA was only increased in astrocytes. In contrast, GW0742 reduced BMP2 and BMP4 mRNA levels in OPCs, with lesser effects in astrocytes. These findings demonstrate that PPARδ plays a role in OPC maturation, mediated, in part, by regulation of BMP and BMP antagonists.
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Kawai K, Itoh T, Itoh A, Horiuchi M, Wakayama K, Bannerman P, Garbern JY, Pleasure D, Lindsten T. Maintenance of the relative proportion of oligodendrocytes to axons even in the absence of BAX and BAK. Eur J Neurosci 2009; 30:2030-41. [PMID: 20128842 DOI: 10.1111/j.1460-9568.2009.06988.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Highly purified oligodendroglial lineage cells from mice lacking functional bax and bak genes were resistant to apoptosis after in-vitro differentiation, indicating an essential role of the intrinsic apoptotic pathway in apoptosis of oligodendrocytes in the absence of neurons (axons) and other glial cells. These mice therefore provide a valuable tool with which to evaluate the significance of the intrinsic apoptotic pathway in regulating the population sizes of oligodendrocytes and oligodendroglial progenitor cells. Quantitative analysis of the optic nerves and the dorsal columns of the spinal cord revealed that the absolute numbers of mature oligodendrocytes immunolabeled for aspartoacylase and adult glial progenitor cells expressing NG2 chondroitin sulfate proteoglycan were increased in both white matter tracts of adult bax/bak-deficient mice and, to a lesser extent, bax-deficient mice, except that there was no increase in NG2-positive progenitor cells in the dorsal columns of these strains of mutant mice. These increases in mature oligodendrocytes and progenitor cells in bax/bak-deficient mice were unexpectedly proportional to increases in numbers of axons in these white matter tracts, thus retaining the oligodendroglial lineage to axon ratios of at most 1.3-fold of the physiological numbers. This is in contrast to the prominent expansion in numbers of neural precursor cells in the subventricular zones of these adult mutant mice. Our study indicates that homeostatic control of cell number is different for progenitors of the oligodendroglial and neuronal lineages. Furthermore, regulatory mechanism(s) operating in addition to apoptotic elimination through the intrinsic pathway, appear to prevent the overproduction of highly mitotic oligodendroglial progenitor cells.
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Affiliation(s)
- Kumi Kawai
- Department of Neurology, University of California, School of Medicine, Sacramento, CA, USA
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