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Osso LA, Hughes EG. Dynamics of mature myelin. Nat Neurosci 2024; 27:1449-1461. [PMID: 38773349 DOI: 10.1038/s41593-024-01642-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/05/2024] [Indexed: 05/23/2024]
Abstract
Myelin, which is produced by oligodendrocytes, insulates axons to facilitate rapid and efficient action potential propagation in the central nervous system. Traditionally viewed as a stable structure, myelin is now known to undergo dynamic modulation throughout life. This Review examines these dynamics, focusing on two key aspects: (1) the turnover of myelin, involving not only the renewal of constituents but the continuous wholesale replacement of myelin membranes; and (2) the structural remodeling of pre-existing, mature myelin, a newly discovered form of neural plasticity that can be stimulated by external factors, including neuronal activity, behavioral experience and injury. We explore the mechanisms regulating these dynamics and speculate that myelin remodeling could be driven by an asymmetry in myelin turnover or reactivation of pathways involved in myelin formation. Finally, we outline how myelin remodeling could have profound impacts on neural function, serving as an integral component of behavioral adaptation.
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Affiliation(s)
- Lindsay A Osso
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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2
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Shamsnia HS, Peyrovinasab A, Amirlou D, Sirouskabiri S, Rostamian F, Basiri N, Shalmani LM, Hashemi M, Hushmandi K, Abdolghaffari AH. BDNF-TrkB Signaling Pathway in Spinal Cord Injury: Insights and Implications. Mol Neurobiol 2024:10.1007/s12035-024-04381-4. [PMID: 39046702 DOI: 10.1007/s12035-024-04381-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 07/18/2024] [Indexed: 07/25/2024]
Abstract
Spinal cord injury (SCI) is a neurodegenerative disorder that has critical impact on patient's life expectance and life span, and this disorder also leads to negative socioeconomic features. SCI is defined as a firm collision to the spinal cord which leads to the fracture and the dislocation of vertebrae. The current available treatment is surgery. However, it cannot fully treat SCI, and many consequences remain after the surgery. Accordingly, finding new therapeutics is critical. BDNF-TrkB signaling is a vital signaling in neuronal differentiation, survival, overgrowth, synaptic plasticity, etc. Hence, many studies evaluate its impact on various neurodegenerative disorders. There are several studies evaluating this signaling in SCI, and they show promising outcomes. It was shown that various exercises, chemical interventions, etc. had significant positive impact on SCI by affecting BDNF-TrkB signaling pathway. This study aims to accumulate and evaluate these data and inspect whether this signaling is effective or not.
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Affiliation(s)
- Hedieh Sadat Shamsnia
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Amirreza Peyrovinasab
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Dorsa Amirlou
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Shirin Sirouskabiri
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Fatemeh Rostamian
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Nasim Basiri
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Leila Mohaghegh Shalmani
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran.
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
| | - Mehrdad Hashemi
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
- Farhikhtegan Medical Convergence Sciences Research Center, Farhikhtegan Hospital Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | | | - Amir Hossein Abdolghaffari
- Department of Toxicology & Pharmacology, Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, No. 99, Yakhchal, Gholhak, Shariati St, P. O. Box: 19419-33111, Tehran, Iran.
- GI Pharmacology Interest Group (GPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
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3
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Ma Z, Zhang W, Wang C, Su Y, Yi C, Niu J. A New Acquaintance of Oligodendrocyte Precursor Cells in the Central Nervous System. Neurosci Bull 2024:10.1007/s12264-024-01261-8. [PMID: 39042298 DOI: 10.1007/s12264-024-01261-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 03/21/2024] [Indexed: 07/24/2024] Open
Abstract
Oligodendrocyte precursor cells (OPCs) are a heterogeneous multipotent population in the central nervous system (CNS) that appear during embryogenesis and persist as resident cells in the adult brain parenchyma. OPCs could generate oligodendrocytes to participate in myelination. Recent advances have renewed our knowledge of OPC biology by discovering novel markers of oligodendroglial cells, the myelin-independent roles of OPCs, and the regulatory mechanism of OPC development. In this review, we will explore the updated knowledge on OPC identity, their multifaceted roles in the CNS in health and diseases, as well as the regulatory mechanisms that are involved in their developmental stages, which hopefully would contribute to a further understanding of OPCs and attract attention in the field of OPC biology.
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Affiliation(s)
- Zexuan Ma
- Department of Histology and Embryology, College of basic medicine, Third Military Medical University, Chongqing, 400038, China
| | - Wei Zhang
- Department of Histology and Embryology, College of basic medicine, Third Military Medical University, Chongqing, 400038, China
| | - Chenmeng Wang
- Department of Histology and Embryology, College of basic medicine, Third Military Medical University, Chongqing, 400038, China
- Research Centre, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
| | - Yixun Su
- Research Centre, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
| | - Chenju Yi
- Research Centre, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China.
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, China.
- Shenzhen Key Laboratory of Chinese Medicine Active substance screening and Translational Research, Shenzhen, 518107, China.
| | - Jianqin Niu
- Department of Histology and Embryology, College of basic medicine, Third Military Medical University, Chongqing, 400038, China.
- Chongqing Key Laboratory of Neurobiology, Chongqing, 400038, China.
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4
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Guardiola-Diaz HM, DiBenedictis BT, Prendaj E, Bansal R. Diverse Responses of Oligodendrocytes to Different FGF-Family Members: Uncoupling Structure-Function Relationship Within FGF Subfamilies. ASN Neuro 2024; 16:2371163. [PMID: 39024549 DOI: 10.1080/17590914.2024.2371163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 03/01/2024] [Indexed: 07/20/2024] Open
Abstract
The fifteen canonical paracrine fibroblast growth factors (FGFs) are organized in five subfamilies that interact with four FGF-receptors (FGFRs) and heparan sulfate proteoglycan (HSPG) co-receptors. Many of these FGFs are expressed in CNS regions where oligodendrocyte (OL) progenitors originate, migrate or differentiate. FGF2 (basic FGF) is considered a prototype FGF and the information about the effects of FGF signaling on OL-lineage cells has evolved largely from the study of FGF2. However, other FGFs from four subfamilies ((FGF1 (FGF1,-2), FGF4 (FGF4,-5,-6), FGF8 (FGF8,-17,-18) and FGF9 (FGF9,-16,-20)) that can interact with the isoforms of FGFRs expressed in OL-lineage cells may also play important roles. We previously reported OL-responses to FGF8 family members. Here, we investigate the effects of members of the FGF1,-4, and -9 subfamilies on proliferation and differentiation of OL progenitors (OPCs), and on cell cycle re-entry and down-regulation of myelin proteins by mature OLs. We found that while FGF2 induced all these responses strongly, FGF4,-6,-9 could do so only transiently and in the presence of exogenous HSPGs, and that FGF5,-16,-20 could not do so even in the presence of heparin or at higher concentrations. Furthermore, we noted that structurally similar FGFs within subfamilies did not always show similarities in their biological effects on OL-lineage cells. Taken together, these studies reveal that FGFs differ in the way they regulate the OL-lineage cells, emphasizes the selectivity and importance of HSPGs as FGF co-receptors in OL-lineage cells and suggests that structural similarity among FGF-subfamily members may not always predict their overlapping biological functions.
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Affiliation(s)
- Hebe M Guardiola-Diaz
- Department of Biology and Neuroscience Program, Trinity College, Hartford, Connecticut, USA
| | - Brett T DiBenedictis
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
| | - Erealda Prendaj
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
| | - Rashmi Bansal
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
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Loreto Palacio P, Pan X, Jones D, Otero JJ. Exploring a distinct FGFR2::DLG5 rearrangement in a low-grade neuroepithelial tumor: A case report and mini-review of protein fusions in brain tumors. J Neuropathol Exp Neurol 2024; 83:567-578. [PMID: 38833313 DOI: 10.1093/jnen/nlae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024] Open
Abstract
We report the novel clinical presentation of a primary brain neoplasm in a 30-year-old man with a mass-like area in the anteromedial temporal lobe. Histopathological analysis revealed a low-grade neuroepithelial tumor with cytologically abnormal neurons and atypical glial cells within the cerebral cortex. Molecular analysis showed a previously undescribed FGFR2::DLG5 rearrangement. We discuss the clinical significance and molecular implications of this fusion event, shedding light on its potential impact on tumor development and patient prognosis. Additionally, an extensive review places the finding in this case in the context of protein fusions in brain tumors in general and highlights their diverse manifestations, underlying molecular mechanisms, and therapeutic implications.
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Affiliation(s)
- Paola Loreto Palacio
- Abigail Wexner Center Research Institute, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Xiaokang Pan
- James Molecular Laboratory, James Cancer Hospital, Columbus, Ohio, USA
| | - Dan Jones
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, USA
| | - José Javier Otero
- Neuropathology Division, Pathology Department, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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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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7
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Qi YB, Xu Z, Shen S, Wang Z, Wang Z. MYRF: A unique transmembrane transcription factor- from proteolytic self-processing to its multifaceted roles in animal development. Bioessays 2024; 46:e2300209. [PMID: 38488284 DOI: 10.1002/bies.202300209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 03/28/2024]
Abstract
The Myelin Regulator Factor (MYRF) is a master regulator governing myelin formation and maintenance in the central nervous system. The conservation of MYRF across metazoans and its broad tissue expression suggest it has functions extending beyond the well-established role in myelination. Loss of MYRF results in developmental lethality in both invertebrates and vertebrates, and MYRF haploinsufficiency in humans causes MYRF-related Cardiac Urogenital Syndrome, underscoring its importance in animal development; however, these mechanisms are largely unexplored. MYRF, an unconventional transcription factor, begins embedded in the membrane and undergoes intramolecular chaperone mediated trimerization, which triggers self-cleavage, allowing its N-terminal segment with an Ig-fold DNA-binding domain to enter the nucleus for transcriptional regulation. Recent research suggests developmental regulation of cleavage, yet the mechanisms remain enigmatic. While some parts of MYRF's structure have been elucidated, others remain obscure, leaving questions about how these motifs are linked to its intricate processing and function.
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Affiliation(s)
- Yingchuan B Qi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhimin Xu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shiqian Shen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhao Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhizhi Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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Baldenius M, Kautzmann S, Nanda S, Klämbt C. Signaling Pathways Controlling Axonal Wrapping in Drosophila. Cells 2023; 12:2553. [PMID: 37947631 PMCID: PMC10647682 DOI: 10.3390/cells12212553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023] Open
Abstract
The rapid transmission of action potentials is an important ability that enables efficient communication within the nervous system. Glial cells influence conduction velocity along axons by regulating the radial axonal diameter, providing electrical insulation as well as affecting the distribution of voltage-gated ion channels. Differentiation of these wrapping glial cells requires a complex set of neuron-glia interactions involving three basic mechanistic features. The glia must recognize the axon, grow around it, and eventually arrest its growth to form single or multiple axon wraps. This likely depends on the integration of numerous evolutionary conserved signaling and adhesion systems. Here, we summarize the mechanisms and underlying signaling pathways that control glial wrapping in Drosophila and compare those to the mechanisms that control glial differentiation in mammals. This analysis shows that Drosophila is a beneficial model to study the development of even complex structures like myelin.
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Affiliation(s)
| | | | | | - Christian Klämbt
- Institute for Neuro- and Behavioral Biology, Faculty of Biology, University of Münster, Röntgenstraße 16, D-48149 Münster, Germany; (M.B.)
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Zhang Q, Chen Z, Zhang K, Zhu J, Jin T. FGF/FGFR system in the central nervous system demyelinating disease: Recent progress and implications for multiple sclerosis. CNS Neurosci Ther 2023; 29:1497-1511. [PMID: 36924298 PMCID: PMC10173727 DOI: 10.1111/cns.14176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND With millions of victims worldwide, multiple sclerosis is the second most common cause of disability among young adults. Although formidable advancements have been made in understanding the disease, the neurodegeneration associated with multiple sclerosis is only partially counteracted by current treatments, and effective therapy for progressive multiple sclerosis remains an unmet need. Therefore, new approaches are required to delay demyelination and the resulting disability and to restore neural function by promoting remyelination and neuronal repair. AIMS The article reviews the latest literature in this field. MATERIALS AND METHODS The fibroblast growth factor (FGF) signaling pathway is a promising target in progressive multiple sclerosis. DISCUSSION FGF signal transduction contributes to establishing the oligodendrocyte lineage, neural stem cell proliferation and differentiation, and myelination of the central nervous system. Furthermore, FGF signaling is implicated in the control of neuroinflammation. In recent years, interventions targeting FGF, and its receptor (FGFR) have been shown to ameliorate autoimmune encephalomyelitis symptoms in multiple sclerosis animal models moderately. CONCLUSION Here, we summarize the recent findings and investigate the role of FGF/FGFR signaling in the onset and progression, discuss the potential therapeutic advances, and offer fresh insights into managing multiple sclerosis.
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Affiliation(s)
- Qingxiang Zhang
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Zhiguo Chen
- Cell Therapy Center, Beijing Institute of Geriatrics, National Clinical Research Center for Geriatric Diseases, Xuanwu Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, China
| | - Kaili Zhang
- Stomatology College of Inner Mongolia Medical University, Hohhot, China
| | - Jie Zhu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurobiology, Care Sciences & Society, Karolinska Institute, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Tao Jin
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
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Takahashi K, Hong L, Kurokawa K, Miyagawa K, Mochida-Saito A, Takeda H, Tsuji M. Brexpiprazole prevents colitis-induced depressive-like behavior through myelination in the prefrontal cortex. Prog Neuropsychopharmacol Biol Psychiatry 2023; 121:110666. [PMID: 36273507 DOI: 10.1016/j.pnpbp.2022.110666] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/10/2022] [Accepted: 10/15/2022] [Indexed: 11/18/2022]
Abstract
Patients with inflammatory bowel disease (IBD) have higher rates of psychiatric pathology including depression. The dextran sulfate sodium (DSS)-treated mice exhibit IBD- and depressive-like phenotypes. A disturbed intestinal environment causes a decrease in serotonin and abnormal myelination in the brain, along with depressive-like behavior in rodents. However, the involvement of these factors in DSS-induced depressive-like behavior in mice remains unclear. In this study, we examined whether myelin proteins in the prefrontal cortex (PFC) and hippocampi were altered in DSS-treated mice, along with the changes in the serotonergic system in the PFC by western blotting and HPLC. The effects of brexpiprazole (Brx), a serotonin modulator, on DSS-induced depressive-like behavior using the tail-suspension test were evaluated. Subsequently, we investigated Brx's effects on the levels of myelin, nodal proteins, and neurotrophic molecules in the PFC with western blotting, and examined the altered node of Ranvier formation by immunohistochemistry. DSS-treated mice showed a reduction in myelin and nodal proteins, dysfunction of the serotonergic system, and impaired formation of the nodes of Ranvier in the PFC. Brx administration prevented the DSS-induced depressive-like behavior and demyelination in the PFC. However, the Brx-mediated effects were inhibited by the selective 5-HT1A antagonist, WAY100635, or the selective TrkB antagonist, ANA-12. Brx decreased the phosphorylation of ERK, CREB, and TrkB along with the expression of BDNF in the PFC of DSS-treated mice. Moreover, the effects of Brx were blocked by WAY100635. These findings indicated that myelination regulated by the activation of the ERK1/2-CREB-BDNF-TrkB pathway in the PFC may be involved in mediating the antidepressant effects of Brx.
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Affiliation(s)
- Kohei Takahashi
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan
| | - Lihua Hong
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan
| | - Kazuhiro Kurokawa
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan
| | - Kazuya Miyagawa
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan
| | - Atsumi Mochida-Saito
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan
| | - Hiroshi Takeda
- Department of Pharmacology, School of Pharmacy at Fukuoka, International University of Health and Welfare, 137-1 Enokizu, Okawa, Fukuoka 831-8501, Japan
| | - Minoru Tsuji
- Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan.
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Xu W, Yu H, Chen D, Pan W, Yang W, Miao J, Jia W, Zheng B, Liu Y, Chen X, Gao Y, Tian D. Identifying the potential transcriptional regulatory network in Hirschsprung disease by integrated analysis of microarray datasets. WORLD JOURNAL OF PEDIATRIC SURGERY 2023; 6:e000547. [PMID: 37082700 PMCID: PMC10111925 DOI: 10.1136/wjps-2022-000547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/13/2023] [Indexed: 04/22/2023] Open
Abstract
Objective Hirschsprung disease (HSCR) is one of the common neurocristopathies in children, which is associated with at least 20 genes and involves a complex regulatory mechanism. Transcriptional regulatory network (TRN) has been commonly reported in regulating gene expression and enteric nervous system development but remains to be investigated in HSCR. This study aimed to identify the potential TRN implicated in the pathogenesis and diagnosis of HSCR. Methods Based on three microarray datasets from the Gene Expression Omnibus database, the multiMiR package was used to investigate the microRNA (miRNA)-target interactions, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Then, we collected transcription factors (TFs) from the TransmiR database to construct the TF-miRNA-mRNA regulatory network and used cytoHubba to identify the key modules. Finally, the receiver operating characteristic (ROC) curve was determined and the integrated diagnostic models were established based on machine learning by the support vector machine method. Results We identified 58 hub differentially expressed microRNAs (DEMis) and 16 differentially expressed mRNAs (DEMs). The robust target genes of DEMis and DEMs mainly enriched in several GO/KEGG terms, including neurogenesis, cell-substrate adhesion, PI3K-Akt, Ras/mitogen-activated protein kinase and Rho/ROCK signaling. Moreover, 2 TFs (TP53 and TWIST1), 4 miRNAs (has-miR-107, has-miR-10b-5p, has-miR-659-3p, and has-miR-371a-5p), and 4 mRNAs (PIM3, CHUK, F2RL1, and CA1) were identified to construct the TF-miRNA-mRNA regulatory network. ROC analysis revealed a strong diagnostic value of the key TRN regulons (all area under the curve values were more than 0.8). Conclusion This study suggests a potential role of the TF-miRNA-mRNA network that can help enrich the connotation of HSCR pathogenesis and diagnosis and provide new horizons for treatment.
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Affiliation(s)
- Wenyao Xu
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Chinese Ministry of Education, Xi'an Jiaotong University, Xi'an, China
| | - Hui Yu
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Chinese Ministry of Education, Xi'an Jiaotong University, Xi'an, China
| | - Dian Chen
- Department of Pulmonary and Critical Care Medicine, Peking University Third Hospital, Peking University, Beijing, China
| | - Weikang Pan
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Weili Yang
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Jing Miao
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wanying Jia
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Baijun Zheng
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Yong Liu
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Chinese Ministry of Education, Xi'an Jiaotong University, Xi'an, China
| | - Xinlin Chen
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Chinese Ministry of Education, Xi'an Jiaotong University, Xi'an, China
| | - Ya Gao
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Donghao Tian
- Department of Pediatric Surgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Chinese Ministry of Education, Xi'an Jiaotong University, Xi'an, China
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12
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Molina-Gonzalez I, Miron VE, Antel JP. Chronic oligodendrocyte injury in central nervous system pathologies. Commun Biol 2022; 5:1274. [PMID: 36402839 PMCID: PMC9675815 DOI: 10.1038/s42003-022-04248-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 11/10/2022] [Indexed: 11/21/2022] Open
Abstract
Myelin, the membrane surrounding neuronal axons, is critical for central nervous system (CNS) function. Injury to myelin-forming oligodendrocytes (OL) in chronic neurological diseases (e.g. multiple sclerosis) ranges from sublethal to lethal, leading to OL dysfunction and myelin pathology, and consequent deleterious impacts on axonal health that drive clinical impairments. This is regulated by intrinsic factors such as heterogeneity and age, and extrinsic cellular and molecular interactions. Here, we discuss the responses of OLs to injury, and perspectives for therapeutic targeting. We put forward that targeting mature OL health in neurological disease is a promising therapeutic strategy to support CNS function.
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Affiliation(s)
- Irene Molina-Gonzalez
- grid.4305.20000 0004 1936 7988United Kingdom Dementia Research Institute at The University of Edinburgh, Edinburgh, Scotland UK ,grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, Chancellor’s Building, The University of Edinburgh, Edinburgh, Scotland UK ,grid.4305.20000 0004 1936 7988Medical Research Council Centre for Reproductive Health, The Queen’s Medical Research Institute, The University of Edinburgh, Edinburgh, Scotland UK
| | - Veronique E. Miron
- grid.4305.20000 0004 1936 7988United Kingdom Dementia Research Institute at The University of Edinburgh, Edinburgh, Scotland UK ,grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, Chancellor’s Building, The University of Edinburgh, Edinburgh, Scotland UK ,grid.4305.20000 0004 1936 7988Medical Research Council Centre for Reproductive Health, The Queen’s Medical Research Institute, The University of Edinburgh, Edinburgh, Scotland UK ,grid.415502.7Barlo Multiple Sclerosis Centre and Keenan Research Centre for Biomedical Science, Toronto, Canada ,grid.17063.330000 0001 2157 2938Department of Immunology, University of Toronto, Toronto, Canada
| | - Jack P. Antel
- grid.14709.3b0000 0004 1936 8649Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, QC Canada
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Dermitzakis I, Manthou ME, Meditskou S, Miliaras D, Kesidou E, Boziki M, Petratos S, Grigoriadis N, Theotokis P. Developmental Cues and Molecular Drivers in Myelinogenesis: Revisiting Early Life to Re-Evaluate the Integrity of CNS Myelin. Curr Issues Mol Biol 2022; 44:3208-3237. [PMID: 35877446 PMCID: PMC9324160 DOI: 10.3390/cimb44070222] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/14/2022] [Accepted: 07/17/2022] [Indexed: 02/07/2023] Open
Abstract
The mammalian central nervous system (CNS) coordinates its communication through saltatory conduction, facilitated by myelin-forming oligodendrocytes (OLs). Despite the fact that neurogenesis from stem cell niches has caught the majority of attention in recent years, oligodendrogenesis and, more specifically, the molecular underpinnings behind OL-dependent myelinogenesis, remain largely unknown. In this comprehensive review, we determine the developmental cues and molecular drivers which regulate normal myelination both at the prenatal and postnatal periods. We have indexed the individual stages of myelinogenesis sequentially; from the initiation of oligodendrocyte precursor cells, including migration and proliferation, to first contact with the axon that enlists positive and negative regulators for myelination, until the ultimate maintenance of the axon ensheathment and myelin growth. Here, we highlight multiple developmental pathways that are key to successful myelin formation and define the molecular pathways that can potentially be targets for pharmacological interventions in a variety of neurological disorders that exhibit demyelination.
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Affiliation(s)
- Iasonas Dermitzakis
- Department of Histology-Embryology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (I.D.); (M.E.M.); (S.M.); (D.M.)
| | - Maria Eleni Manthou
- Department of Histology-Embryology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (I.D.); (M.E.M.); (S.M.); (D.M.)
| | - Soultana Meditskou
- Department of Histology-Embryology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (I.D.); (M.E.M.); (S.M.); (D.M.)
| | - Dimosthenis Miliaras
- Department of Histology-Embryology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (I.D.); (M.E.M.); (S.M.); (D.M.)
| | - Evangelia Kesidou
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, AHEPA University Hospital, 54621 Thessaloniki, Greece; (E.K.); (M.B.); (N.G.)
| | - Marina Boziki
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, AHEPA University Hospital, 54621 Thessaloniki, Greece; (E.K.); (M.B.); (N.G.)
| | - Steven Petratos
- Department of Neuroscience, Central Clinical School, Monash University, Prahran, VIC 3004, Australia;
| | - Nikolaos Grigoriadis
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, AHEPA University Hospital, 54621 Thessaloniki, Greece; (E.K.); (M.B.); (N.G.)
| | - Paschalis Theotokis
- Department of Histology-Embryology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (I.D.); (M.E.M.); (S.M.); (D.M.)
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, AHEPA University Hospital, 54621 Thessaloniki, Greece; (E.K.); (M.B.); (N.G.)
- Correspondence:
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Tong LY, Deng YB, Du WH, Zhou WZ, Liao XY, Jiang X. Clemastine Promotes Differentiation of Oligodendrocyte Progenitor Cells Through the Activation of ERK1/2 via Muscarinic Receptors After Spinal Cord Injury. Front Pharmacol 2022; 13:914153. [PMID: 35865954 PMCID: PMC9294397 DOI: 10.3389/fphar.2022.914153] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The recovery of spinal cord injury (SCI) is closely associated with the obstruction of oligodendrocyte progenitor cell (OPC) differentiation, which ultimately induces the inability to generate newly formed myelin. To address the concern, drug-based methods may be the most practical and feasible way, possibly applying to clinical therapies for patients with SCI. In our previous study, we found that clemastine treatment preserves myelin integrity, decreases the loss of axons, and improves functional recovery in the SCI model. Clemastine acts as an antagonist of the muscarinic acetylcholine receptor (muscarinic receptor, MR) identified from a string of anti-muscarinic drugs that can enhance oligodendrocyte differentiation and myelin wrapping. However, the effects of clemastine on OPC differentiation through MRs in SCI and the underlying mechanism remain unclear. To explore the possibility, a rat model of SCI was established. To investigate if clemastine could promote the differentiation of OPCs in SCI via MR, the expressions of OPC and mature OL were detected at 7 days post injury (dpi) or at 14 dpi. The significant effect of clemastine on encouraging OPC differentiation was revealed at 14 dpi rather than 7 dpi. Under pre-treatment with the MR agonist cevimeline, the positive role of clemastine on OPC differentiation was partially disrupted. Further studies indicated that clemastine increased the phosphorylation level of extracellular signal–regulated kinase 1/2 (p-ERK1/2) and the expressions of transcription factors, Myrf and Olig2. To determine the relationship among clemastine, ERK1/2 signaling, specified transcription factors, and OPC differentiation, the ERK1/2 signaling was disturbed by U0126. The inhibition of ERK1/2 in SCI rats treated with clemastine decreased the expressions of p-ERK 1/2, Myrf, Olig2, and mature OLs, suggesting that ERK1/2 is required for clemastine on promoting OPC differentiation and that specified transcription factors may be affected by the activity of ERK1/2. Moreover, the impact of clemastine on modulating the level of p-ERK 1/2 was restricted following cevimeline pre-injecting, which provides further evidence that the role of clemastine was mediated by MRs. Altogether, our data demonstrated that clemastine, mediated by MRs, promotes OPC differentiation under the enhancement of Myrf and Olig2 by activating ERK1/2 signaling and suggests a novel therapeutic prospect for SCI recovery.
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Affiliation(s)
- Lu-Yao Tong
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, College of Basic Medicine, Chongqing Medical University, Chongqing, China
| | - Yong-Bing Deng
- Department of Chongqing Emergency Medical Center, Chongqing University Center Hospital, School of Medicine, Chongqing University, Chongqing, China
| | - Wei-Hong Du
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, College of Basic Medicine, Chongqing Medical University, Chongqing, China
| | - Wen-Zhu Zhou
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, College of Basic Medicine, Chongqing Medical University, Chongqing, China
| | - Xin-Yu Liao
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, College of Basic Medicine, Chongqing Medical University, Chongqing, China
| | - Xue Jiang
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, College of Basic Medicine, Chongqing Medical University, Chongqing, China
- *Correspondence: Xue Jiang, ,
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Ornitz DM, Itoh N. New developments in the biology of fibroblast growth factors. WIREs Mech Dis 2022; 14:e1549. [PMID: 35142107 PMCID: PMC10115509 DOI: 10.1002/wsbm.1549] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/28/2023]
Abstract
The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nobuyuki Itoh
- Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto, Japan
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Zhao Y, Liang Y, Xu Z, Liu J, Liu X, Ma J, Sun C, Yang Y. Exosomal miR-673-5p from fibroblasts promotes Schwann cell-mediated peripheral neuron myelination by targeting the TSC2/mTORC1/SREBP2 axis. J Biol Chem 2022; 298:101718. [PMID: 35151688 PMCID: PMC8908274 DOI: 10.1016/j.jbc.2022.101718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/30/2022] Open
Abstract
Peripheral myelination is a complicated process, wherein Schwann cells (SCs) promote the formation of the myelin sheath around the axons of peripheral neurons. Fibroblasts are the second resident cells in the peripheral nerves; however, the precise function of fibroblasts in SC-mediated myelination has rarely been examined. Here, we show that exosomes derived from fibroblasts boost myelination-related gene expression in SCs. We used exosome sequencing, together with bioinformatic analysis, to demonstrate that exosomal microRNA miR-673-5p is capable of stimulating myelin gene expression in SCs. Subsequent functional studies revealed that miR-673-5p targets the regulator of mechanistic target of the rapamycin (mTOR) complex 1 (mTORC1) tuberous sclerosis complex 2 in SCs, leading to the activation of downstream signaling pathways including mTORC1 and sterol-regulatory element binding protein 2. In vivo experiments further confirmed that miR-673-5p activates the tuberous sclerosis complex 2/mTORC1/sterol-regulatory element binding protein 2 axis, thus promoting the synthesis of cholesterol and related lipids and subsequently accelerating myelin sheath maturation in peripheral nerves. Overall, our findings revealed exosome-mediated cross talk between fibroblasts and SCs that plays a pivotal role in peripheral myelination. We propose that exosomes derived from fibroblasts and miR-673-5p might be useful for promoting peripheral myelination in translational medicine.
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Affiliation(s)
- Yahong Zhao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China.
| | - Yunyun Liang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Zhixin Xu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Jina Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Xiaoyu Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Jinyu Ma
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Cheng Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China.
| | - Yumin Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education; Co-innovation Center of Neurogeneration; NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China.
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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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Lee SH, Rezzonico MG, Friedman BA, Huntley MH, Meilandt WJ, Pandey S, Chen YJJ, Easton A, Modrusan Z, Hansen DV, Sheng M, Bohlen CJ. TREM2-independent oligodendrocyte, astrocyte, and T cell responses to tau and amyloid pathology in mouse models of Alzheimer disease. Cell Rep 2021; 37:110158. [DOI: 10.1016/j.celrep.2021.110158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 09/11/2021] [Accepted: 12/01/2021] [Indexed: 01/04/2023] Open
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The oligodendrocyte-enriched orphan G protein-coupled receptor Gpr62 is dispensable for central nervous system myelination. Neural Dev 2021; 16:6. [PMID: 34844642 PMCID: PMC8630896 DOI: 10.1186/s13064-021-00156-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Myelination is a highly regulated process in the vertebrate central nervous system (CNS) whereby oligodendrocytes wrap axons with multiple layers of insulating myelin in order to allow rapid electrical conduction. Establishing the proper pattern of myelin in neural circuits requires communicative axo-glial interactions, however, the molecular interactions that occur between oligodendrocytes and axons during developmental myelination and myelin maintenance remain to be fully elucidated. Our previous work identified G protein-coupled receptor 62 (Gpr62), an uncharacterized orphan g-protein coupled receptor, as being selectively expressed by mature oligodendrocytes within the CNS, suggesting a potential role in myelination or axoglial interactions. However, no studies to date have assessed the functional requirement for Gpr62 in oligodendrocyte development or CNS myelination. METHODS To address this, we generated a knockout mouse strain lacking the Gpr62 gene. We assessed CNS myelination during both postnatal development and adulthood using immunohistochemistry, electron microscopy and western blot. In addition, we utilized AAV-mediated expression of a tagged Gpr62 in oligodendrocytes to determine the subcellular localization of the protein in vivo. RESULTS We find that virally expressed Gpr62 protein is selectively expressed on the adaxonal myelin layer, suggestive of a potential role for Gpr62 in axo-myelinic signaling. Nevertheless, Gpr62 knockout mice display normal oligodendrocyte numbers and apparently normal myelination within the CNS during both postnatal development and adulthood. CONCLUSIONS We conclude that in spite of being well-placed to mediate neuronal-oligodendrocyte communications, Gpr62 is overall dispensable for CNS myelination.
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Disturbance of prefrontal cortical myelination in olfactory bulbectomized mice is associated with depressive-like behavior. Neurochem Int 2021; 148:105112. [PMID: 34171413 DOI: 10.1016/j.neuint.2021.105112] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/10/2021] [Accepted: 06/20/2021] [Indexed: 12/28/2022]
Abstract
Recent studies have reported that demyelination is associated with the development of depression. Olfactory bulbectomized (OBX) rodents are a useful experimental animal model for depressive disorder. However, little is known about the change in myelination in the brain of OBX mice. To address this question, we observed depressive-like behavior of OBX mice in the tail-suspension test, and determined the quantity of myelin proteins in the prefrontal cortex (PFC), striatum and hippocampus on day 14 or 21 after surgery. The number of nodes of Ranvier paired with the paranodal marker contactin-associated protein (Caspr), as well as the numbers of immature and mature oligodendrocytes in the PFC, were also measured on day 21 after surgery. We examined whether these behavioral and neurochemical changes observed in OBX mice were reversed by chronic administration of imipramine. OBX mice showed depressive-like behavior in the tail-suspension test together with a decrease in the levels of myelin proteins such as myelin basic protein, myelin-associated glycoprotein and cyclicnucleotide phosphodiesterase in the PFC on day 21 after surgery. The number of nodes of Ranvier and mature oligodendrocytes were also decreased in the PFC of OBX mice, while the number of immature oligodendrocytes was increased on day 21 after surgery. However, the number of immature oligodendrocytes in the PFC of OBX mice was decreased on day 35 after surgery. Administration of imipramine (20 mg/kg) for 2 weeks from day 21 after surgery improved OBX-induced depressive-like behavior and abnormal myelination in the PFC. The present findings suggest that the disturbance of myelin function in the PFC may contribute to the pathophysiology of depression, and further support the notion that it plays an important role in the psychological state.
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Ishii A, Furusho M, Bansal R. Mek/ERK1/2-MAPK and PI3K/Akt/mTOR signaling plays both independent and cooperative roles in Schwann cell differentiation, myelination and dysmyelination. Glia 2021; 69:2429-2446. [PMID: 34157170 DOI: 10.1002/glia.24049] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/29/2021] [Accepted: 06/04/2021] [Indexed: 01/15/2023]
Abstract
Multiple signals are involved in the regulation of developmental myelination by Schwann cells and in the maintenance of a normal myelin homeostasis throughout adult life, preserving the integrity of the axons in the PNS. Recent studies suggest that Mek/ERK1/2-MAPK and PI3K/Akt/mTOR intracellular signaling pathways play important, often overlapping roles in the regulation of myelination in the PNS. In addition, hyperactivation of these signaling pathways in Schwann cells leads to a late onset of various pathological changes in the sciatic nerves. However, it remains poorly understood whether these pathways function independently or sequentially or converge using a common mechanism to facilitate Schwann cell differentiation and myelin growth during development and in causing pathological changes in the adult animals. To address these questions, we analyzed multiple genetically modified mice using simultaneous loss- and constitutive gain-of-function approaches. We found that during development, the Mek/ERK1/2-MAPK pathway plays a primary role in Schwann cell differentiation, distinct from mTOR. However, during active myelination, ERK1/2 is dependent on mTOR signaling to drive the growth of the myelin sheath and regulate its thickness. Finally, our data suggest that peripheral nerve pathology during adulthood caused by hyperactivation of Mek/ERK1/2-MAPK or PI3K is likely to be independent or dependent on mTOR-signaling in different contexts. Thus, this study highlights the complexities in the roles played by two major intracellular signaling pathways in Schwann cells that affect their differentiation, myelination, and later PNS pathology and predicts that potential therapeutic modulation of these pathways in PNS neuropathies could be a complex process.
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Affiliation(s)
- Akihiro Ishii
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Miki Furusho
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Rashmi Bansal
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA
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22
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El-Derany MO, Noureldein MH. Bone marrow mesenchymal stem cells and their derived exosomes resolve doxorubicin-induced chemobrain: critical role of their miRNA cargo. Stem Cell Res Ther 2021; 12:322. [PMID: 34090498 PMCID: PMC8180158 DOI: 10.1186/s13287-021-02384-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/13/2021] [Indexed: 02/06/2023] Open
Abstract
Background Doxorubicin (DOX), a widely used chemotherapeutic agent, can cause neurodegeneration in the brain, which leads to a condition known as chemobrain. In fact, chemobrain is a deteriorating condition which adversely affects the lives of cancer survivors. This study aimed to examine the potential therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) and their derived exosomes (BMSCs-Exo) in DOX-induced chemobrain in rat models. Methods Chemobrain was induced by exposing rats to DOX (2 mg/kg, i.p) once weekly for 4 consecutive weeks. After 48 h of the last DOX dose, a subset of rats was supplied with either an intravenous injection of BMSCs (1 × 106) or a single dose of 150 μg of BMSCs-Exo. Behavioral tests were conducted 7 days post injection. Rats were sacrificed after 14 days from BMSCs or BMSCs-Exo injection. Results BMSCs and BMSCs-Exo successfully restored DOX-induced cognitive and behavioral distortion. These actions were mediated via decreasing hippocampal neurodegeneration and neural demyelination through upregulating neural myelination factors (myelin%, Olig2, Opalin expression), neurotropic growth factors (BDNF, FGF-2), synaptic factors (synaptophysin), and fractalkine receptor expression (Cx3cr1). Halting neurodegeneration in DOX-induced chemobrain was achieved through epigenetic induction of key factors in Wnt/β-catenin and hedgehog signaling pathways mediated primarily by the most abundant secreted exosomal miRNAs (miR-21-5p, miR-125b-5p, miR-199a-3p, miR-24-3p, let-7a-5p). Moreover, BMSCs and BMSCs-Exo significantly abrogate the inflammatory state (IL-6, TNF-α), apoptotic state (BAX/Bcl2), astrocyte, and microglia activation (GFAP, IBA-1) in DOX-induced chemobrain with a significant increase in the antioxidant mediators (GSH, GPx, SOD activity). Conclusions BMSCs and their derived exosomes offer neuroprotection against DOX-induced chemobrain via genetic and epigenetic abrogation of hippocampal neurodegeneration through modulating Wnt/β-catenin and hedgehog signaling pathways and through reducing inflammatory, apoptotic, and oxidative stress state. Graphical abstract Proposed mechanisms of the protective effects of bone marrow stem cells (BMSCs) and their exosomes (BMSCs-Exo) in doxorubicin (DOX)-induced chemobrain. Blue arrows: induce. Red arrows: inhibit.
![]() Supplementary Information The online version contains supplementary material available at 10.1186/s13287-021-02384-9.
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Affiliation(s)
- Marwa O El-Derany
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, 11566, Egypt.
| | - Mohamed H Noureldein
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, 11566, Egypt.,Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,American University of Beirut Diabetes Program, Beirut, Lebanon
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Effects of FGFR Tyrosine Kinase Inhibition in OLN-93 Oligodendrocytes. Cells 2021; 10:cells10061318. [PMID: 34070622 PMCID: PMC8228431 DOI: 10.3390/cells10061318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 12/15/2022] Open
Abstract
Fibroblast growth factor (FGF) signaling is involved in the pathogenesis of multiple sclerosis (MS). Data from neuropathology studies suggest that FGF signaling contributes to the failure of remyelination in MS. In MOG35–55-induced EAE, oligodendrocyte-specific deletion of FGFR1 and FGFR2 resulted in a less severe disease course, reduced inflammation, myelin and axon degeneration and changed FGF/FGFR and BDNF/TrkB signaling. Since signaling cascades in oligodendrocytes could not be investigated in the EAE studies, we here aimed to characterize FGFR-dependent oligodendrocyte-specific signaling in vitro. FGFR inhibition was achieved by application of the multi-kinase-inhibitor dovitinib and the FGFR1/2/3-inhibitor AZD4547. Both substances are potent inhibitors of FGF signaling; they are effective in experimental tumor models and patients with malignancies. Effects of FGFR inhibition in oligodendrocytes were studied by immunofluorescence microscopy, protein and gene analyses. Application of the tyrosine kinase inhibitors reduced FGFR1, phosphorylated ERK and Akt expression, and it enhanced BDNF and TrkB expression. Furthermore, the myelin proteins CNPase and PLP were upregulated by FGFR inhibition. In summary, inhibition of FGFR signaling in oligodendrocytes can be achieved by application of tyrosine kinase inhibitors. Decreased phosphorylation of ERK and Akt is associated with an upregulation of BDNF/TrkB signaling, which may be responsible for the increased production of myelin proteins. Furthermore, these data suggest that application of FGFR inhibitors may have the potential to promote remyelination in the CNS.
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Saiki T, Nakamura N, Miyabe M, Ito M, Minato T, Sango K, Matsubara T, Naruse K. The Effects of Insulin on Immortalized Rat Schwann Cells, IFRS1. Int J Mol Sci 2021; 22:ijms22115505. [PMID: 34071138 PMCID: PMC8197103 DOI: 10.3390/ijms22115505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 01/02/2023] Open
Abstract
Schwann cells play an important role in peripheral nerve function, and their dysfunction has been implicated in the pathogenesis of diabetic neuropathy and other demyelinating diseases. The physiological functions of insulin in Schwann cells remain unclear and therefore define the aim of this study. By using immortalized adult Fischer rat Schwann cells (IFRS1), we investigated the mechanism of the stimulating effects of insulin on the cell proliferation and expression of myelin proteins (myelin protein zero (MPZ) and myelin basic protein (MBP). The application of insulin to IFRS1 cells increased the proliferative activity and induced phosphorylation of Akt and ERK, but not P38-MAPK. The proliferative potential of insulin-stimulated IFRS1 was significantly suppressed by the addition of LY294002, a PI3 kinase inhibitor. The insulin-stimulated increase in MPZ expression was significantly suppressed by the addition of PD98059, a MEK inhibitor. Furthermore, insulin-increased MBP expression was significantly suppressed by the addition of LY294002. These findings suggest that both PI3-K/Akt and ERK/MEK pathways are involved in insulin-induced cell growth and upregulation of MPZ and MBP in IFRS1 Schwann cells.
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Affiliation(s)
- Tomokazu Saiki
- Department of Pharmacy, Aichi Gakuin University Dental Hospital, Nagoya 464-8651, Japan;
| | - Nobuhisa Nakamura
- Department of Internal Medicine, School of Dentistry, Aichi Gakuin University, Nagoya 464-8651, Japan; (M.M.); (M.I.); (T.M.); (K.N.)
- Correspondence: ; Tel.: +81-52-759-2111; Fax: +81-52-759-2168
| | - Megumi Miyabe
- Department of Internal Medicine, School of Dentistry, Aichi Gakuin University, Nagoya 464-8651, Japan; (M.M.); (M.I.); (T.M.); (K.N.)
| | - Mizuho Ito
- Department of Internal Medicine, School of Dentistry, Aichi Gakuin University, Nagoya 464-8651, Japan; (M.M.); (M.I.); (T.M.); (K.N.)
| | - Tomomi Minato
- Department of Clinical Laboratory, Aichi Gakuin University Dental Hospital, Nagoya 464-8651, Japan;
| | - Kazunori Sango
- Diabetic Neuropathy Project, Department of Diseases and Infection, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan;
| | - Tatsuaki Matsubara
- Department of Internal Medicine, School of Dentistry, Aichi Gakuin University, Nagoya 464-8651, Japan; (M.M.); (M.I.); (T.M.); (K.N.)
| | - Keiko Naruse
- Department of Internal Medicine, School of Dentistry, Aichi Gakuin University, Nagoya 464-8651, Japan; (M.M.); (M.I.); (T.M.); (K.N.)
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25
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Epstein RJ, Tian LJ, Gu YF. 2b or Not 2b: How Opposing FGF Receptor Splice Variants Are Blocking Progress in Precision Oncology. JOURNAL OF ONCOLOGY 2021; 2021:9955456. [PMID: 34007277 PMCID: PMC8110382 DOI: 10.1155/2021/9955456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/21/2021] [Indexed: 01/16/2023]
Abstract
More than ten thousand peer-reviewed studies have assessed the role of fibroblast growth factors (FGFs) and their receptors (FGFRs) in cancer, but few patients have yet benefited from drugs targeting this molecular family. Strategizing how best to use FGFR-targeted drugs is complicated by multiple variables, including RNA splicing events that alter the affinity of ligands for FGFRs and hence change the outcomes of stromal-epithelial interactions. The effects of splicing are most relevant to FGFR2; expression of the FGFR2b splice isoform can restore apoptotic sensitivity to cancer cells, whereas switching to FGFR2c may drive tumor progression by triggering epithelial-mesenchymal transition. The differentiating and regulatory actions of wild-type FGFR2b contrast with the proliferative actions of FGFR1 and FGFR3, and may be converted to mitogenicity either by splice switching or by silencing of tumor suppressor genes such as CDH1 or PTEN. Exclusive use of small-molecule pan-FGFR inhibitors may thus cause nonselective blockade of FGFR2 isoforms with opposing actions, undermining the rationale of FGFR2 drug targeting. This splice-dependent ability of FGFR2 to switch between tumor-suppressing and -driving functions highlights an unmet oncologic need for isoform-specific drug targeting, e.g., by antibody inhibition of ligand-FGFR2c binding, as well as for more nuanced molecular pathology prediction of FGFR2 actions in different stromal-tumor contexts.
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Affiliation(s)
- Richard J. Epstein
- New Hope Cancer Center, Beijing United Hospital, 9-11 Jiangtai West Rd, Chaoyang, Beijing 100015, China
- Garvan Institute of Medical Research and UNSW Clinical School, 84 Victoria St, Darlinghurst 2010 Sydney, Australia
| | - Li Jun Tian
- New Hope Cancer Center, Beijing United Hospital, 9-11 Jiangtai West Rd, Chaoyang, Beijing 100015, China
| | - Yan Fei Gu
- New Hope Cancer Center, Beijing United Hospital, 9-11 Jiangtai West Rd, Chaoyang, Beijing 100015, China
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26
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Rajendran R, Böttiger G, Stadelmann C, Karnati S, Berghoff M. FGF/FGFR Pathways in Multiple Sclerosis and in Its Disease Models. Cells 2021; 10:884. [PMID: 33924474 PMCID: PMC8068804 DOI: 10.3390/cells10040884] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/01/2021] [Accepted: 04/10/2021] [Indexed: 12/19/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS) affecting more than two million people worldwide. In MS, oligodendrocytes and myelin sheaths are destroyed by autoimmune-mediated inflammation, while remyelination is impaired. Recent investigations of post-mortem tissue suggest that Fibroblast growth factor (FGF) signaling may regulate inflammation and myelination in MS. FGF2 expression seems to correlate positively with macrophages/microglia and negatively with myelination; FGF1 was suggested to promote remyelination. In myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis (EAE), systemic deletion of FGF2 suggested that FGF2 may promote remyelination. Specific deletion of FGF receptors (FGFRs) in oligodendrocytes in this EAE model resulted in a decrease of lymphocyte and macrophage/microglia infiltration as well as myelin and axon degeneration. These effects were mediated by ERK/Akt phosphorylation, a brain-derived neurotrophic factor, and downregulation of inhibitors of remyelination. In the first part of this review, the most important pharmacotherapeutic principles for MS will be illustrated, and then we will review recent advances made on FGF signaling in MS. Thus, we will suggest application of FGFR inhibitors, which are currently used in Phase II and III cancer trials, as a therapeutic option to reduce inflammation and induce remyelination in EAE and eventually MS.
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MESH Headings
- Animals
- Brain-Derived Neurotrophic Factor/genetics
- Brain-Derived Neurotrophic Factor/immunology
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Fibroblast Growth Factor 2/deficiency
- Fibroblast Growth Factor 2/genetics
- Gene Expression Regulation
- Humans
- Immunologic Factors/therapeutic use
- Mice, Knockout
- Microglia/drug effects
- Microglia/immunology
- Microglia/pathology
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/genetics
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
- Myelin Sheath/drug effects
- Myelin Sheath/immunology
- Myelin Sheath/pathology
- Myelin-Oligodendrocyte Glycoprotein/administration & dosage
- Oligodendroglia/drug effects
- Oligodendroglia/immunology
- Oligodendroglia/pathology
- Peptide Fragments/administration & dosage
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/immunology
- Receptor, Fibroblast Growth Factor, Type 2/antagonists & inhibitors
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/immunology
- Remyelination/drug effects
- Remyelination/genetics
- Remyelination/immunology
- Signal Transduction
- Mice
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Affiliation(s)
- Ranjithkumar Rajendran
- Experimental Neurology, Department of Neurology, University of Giessen, Klinikstrasse 33, 35385 Giessen, Germany; (R.R.); (G.B.)
| | - Gregor Böttiger
- Experimental Neurology, Department of Neurology, University of Giessen, Klinikstrasse 33, 35385 Giessen, Germany; (R.R.); (G.B.)
| | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany;
| | - Srikanth Karnati
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstrasse 6, 97080 Würzburg, Germany;
| | - Martin Berghoff
- Experimental Neurology, Department of Neurology, University of Giessen, Klinikstrasse 33, 35385 Giessen, Germany; (R.R.); (G.B.)
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27
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Fletcher JL, Makowiecki K, Cullen CL, Young KM. Oligodendrogenesis and myelination regulate cortical development, plasticity and circuit function. Semin Cell Dev Biol 2021; 118:14-23. [PMID: 33863642 DOI: 10.1016/j.semcdb.2021.03.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/17/2022]
Abstract
During cortical development and throughout adulthood, oligodendrocytes add myelin internodes to glutamatergic projection neurons and GABAergic inhibitory neurons. In addition to directing node of Ranvier formation, to enable saltatory conduction and influence action potential transit time, oligodendrocytes support axon health by communicating with axons via the periaxonal space and providing metabolic support that is particularly critical for healthy ageing. In this review we outline the timing of oligodendrogenesis in the developing mouse and human cortex and describe the important role that oligodendrocytes play in sustaining and modulating neuronal function. We also provide insight into the known and speculative impact that myelination has on cortical axons and their associated circuits during the developmental critical periods and throughout life, particularly highlighting their life-long role in learning and remembering.
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Affiliation(s)
- Jessica L Fletcher
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Kalina Makowiecki
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Carlie L Cullen
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.
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28
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Wu K, Yue J, Shen K, He J, Zhu G, Liu S, Yang H, Zhang CQ. Expression and cellular distribution of FGF13 in cortical tubers of the tuberous sclerosis complex. Neurosci Lett 2021; 749:135714. [PMID: 33582188 DOI: 10.1016/j.neulet.2021.135714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/14/2021] [Accepted: 02/03/2021] [Indexed: 02/05/2023]
Abstract
Cortical tubers in patients with tuberous sclerosis complex (TSC) are highly associated with intractable epilepsy. Recent evidence suggests a close relationship between FGF13 and seizures. To understand the role of FGF13 in the pathogenesis of cortical tubers, we investigated the expression pattern of FGF13 in cortical tubers of TSC compared with normal control cortices (CTX). We found that both the mRNA and protein levels of FGF13 were significantly higher in the cortical tubers from patients with TSC than in the control cortices. The immunohistochemical results showed strong FGF13 immunoreactivity in abnormal cells, including dysplastic neurons (DNs) and giant cells (GCs). Moreover, double-label immunofluorescence analyses confirmed that FGF13 was mainly localized in neurons and nearly absent in glia-like cells. The protein levels of FGF13 in the TSC samples were positively correlated with the frequency of seizures before surgery. Taken together, these results suggest that the overexpression and distribution pattern of FGF13 may be related to intractable epilepsy caused by TSC.
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Affiliation(s)
- Kefu Wu
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jiong Yue
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Kaifeng Shen
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jiaojiang He
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Gang Zhu
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Shiyong Liu
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Yang
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China.
| | - Chun-Qing Zhang
- Epilepsy Research Center of PLA, Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China.
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29
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Kamali S, Rajendran R, Stadelmann C, Karnati S, Rajendran V, Giraldo-Velasquez M, Berghoff M. Oligodendrocyte-specific deletion of FGFR2 ameliorates MOG 35-55 -induced EAE through ERK and Akt signalling. Brain Pathol 2021; 31:297-311. [PMID: 33103299 PMCID: PMC8018040 DOI: 10.1111/bpa.12916] [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: 07/30/2020] [Revised: 10/09/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies including multiple sclerosis (MS). In our recent study, oligodendrocyte‐specific deletion of FGFR1 resulted in a milder disease course, less inflammation, reduced myelin and axon damage in EAE. The objective of this study was to elucidate the role of oligodendroglial FGFR2 in MOG35‐55‐induced EAE. Oligodendrocyte‐specific knockout of FGFR2 (Fgfr2ind−/−) was achieved by application of tamoxifen; EAE was induced using the MOG35‐55 peptide. EAE symptoms were monitored over 62 days. Spinal cord tissue was analysed by histology, immunohistochemistry and western blot. Fgfr2ind−/− mice revealed a milder disease course, less myelin damage and enhanced axonal density. The number of oligodendrocytes was not affected in demyelinated areas. However, protein expression of FGFR2, FGF2 and FGF9 was downregulated in Fgfr2ind−/− mice. FGF/FGFR dependent signalling proteins were differentially regulated; pAkt was upregulated and pERK was downregulated in Fgfr2ind−/− mice. The number of CD3(+) T cells, Mac3(+) cells and B220(+) B cells was less in demyelinated lesions of Fgfr2ind−/− mice. Furthermore, expression of IL‐1β, TNF‐α and CD200 was less in Fgfr2ind−/− mice than controls. Fgfr2ind−/− mice showed an upregulation of PLP and downregulation of the remyelination inhibitors SEMA3A and TGF‐β expression. These data suggest that cell‐specific deletion of FGFR2 in oligodendrocytes has anti‐inflammatory and neuroprotective effects accompanied by changes in FGF/FGFR dependent signalling, inflammatory cytokines and expression of remyelination inhibitors. Thus, FGFRs in oligodendrocytes may represent potential targets for the treatment of inflammatory and demyelinating diseases including MS.
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Affiliation(s)
- Salar Kamali
- Department of Neurology, University of Giessen, Giessen, Germany
| | | | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Srikanth Karnati
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | | | | | - Martin Berghoff
- Department of Neurology, University of Giessen, Giessen, Germany
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30
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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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31
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R-Ras GTPases Signaling Role in Myelin Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21165911. [PMID: 32824627 PMCID: PMC7460555 DOI: 10.3390/ijms21165911] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/18/2022] Open
Abstract
Myelination is required for fast and efficient synaptic transmission in vertebrates. In the central nervous system, oligodendrocytes are responsible for creating myelin sheaths that isolate and protect axons, even throughout adulthood. However, when myelin is lost, the failure of remyelination mechanisms can cause neurodegenerative myelin-associated pathologies. From oligodendrocyte progenitor cells to mature myelinating oligodendrocytes, myelination is a highly complex process that involves many elements of cellular signaling, yet many of the mechanisms that coordinate it, remain unknown. In this review, we will focus on the three major pathways involved in myelination (PI3K/Akt/mTOR, ERK1/2-MAPK, and Wnt/β-catenin) and recent advances describing the crosstalk elements which help to regulate them. In addition, we will review the tight relation between Ras GTPases and myelination processes and discuss its potential as novel elements of crosstalk between the pathways. A better understanding of the crosstalk elements orchestrating myelination mechanisms is essential to identify new potential targets to mitigate neurodegeneration.
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32
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Gao ZZ, Li YC, Shao CY, Xiao J, Shen Y, Zhou L. EPAC Negatively Regulates Myelination via Controlling Proliferation of Oligodendrocyte Precursor Cells. Neurosci Bull 2020; 36:639-648. [PMID: 32303914 DOI: 10.1007/s12264-020-00495-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 01/05/2020] [Indexed: 12/17/2022] Open
Abstract
Increasing evidence suggests that a cyclic adenosine monophosphate (cAMP)-dependent intracellular signal drives the process of myelination. Yet, the signal transduction underlying the action of cAMP on central nervous system myelination remains undefined. In the present work, we sought to determine the role of EPAC (exchange protein activated by cAMP), a downstream effector of cAMP, in the development of the myelin sheath using EPAC1 and EPAC2 double-knockout (EPACdKO) mice. The results showed an age-dependent regulatory effect of EPAC1 and EPAC2 on myelin development, as their deficiency caused more myelin sheaths in postnatal early but not late adult mice. Knockout of EPAC promoted the proliferation of oligodendrocyte precursor cells and had diverse effects on myelin-related transcription factors, which in turn increased the expression of myelin-related proteins. These results indicate that EPAC proteins are negative regulators of myelination and may be promising targets for the treatment of myelin-related diseases.
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Affiliation(s)
- Zhen-Zhen Gao
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China
| | - Ying-Cong Li
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Chong-Yu Shao
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jian Xiao
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China
| | - Ying Shen
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Liang Zhou
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China. .,Key Laboratory of Brain Science, Guizhou Institution of Higher Education, Zunyi Medical University, Zunyi, 563000, China.
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33
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Kang W, Nguyen KCQ, Hébert JM. Transient Redirection of SVZ Stem Cells to Oligodendrogenesis by FGFR3 Activation Promotes Remyelination. Stem Cell Reports 2020; 12:1223-1231. [PMID: 31189094 PMCID: PMC6565886 DOI: 10.1016/j.stemcr.2019.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 01/02/2023] Open
Abstract
Stimulating oligodendrocyte (OL) production from endogenous progenitor cells is an important strategy for myelin repair and functional restoration after disease or injury-induced demyelination. Subventricular zone (SVZ) stem cells are multipotential, generating neurons and oligodendroglia. The factors that regulate the fate of these stem cells are poorly defined. In this study, we show that genetically increasing fibroblast growth factor receptor-3 (FGFR3) activity in adult SVZ stem cells transiently and dramatically redirects their differentiation from the neuronal to the oligodendroglial lineage after pathological demyelination. The increased SVZ-derived oligodendrogenesis leads to improved OL regeneration and myelin repair, not only in the corpus callosum (a normal destination for SVZ-derived oligodendroglial cells), but also in the lower cortical layers. This study identifies FGF signaling as a potent target for improving endogenous SVZ-derived OL regeneration and remyelination. Adult neuronal progenitors with increased FGFR activity switch to gliogenesis in vivo FGFR-induced increase in OPCs (30-fold) and oligodendrocytes (10-fold) is reversible FGFR-induced increase in oligodendrocytes results in remyelination after chronic insult
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Affiliation(s)
- Wenfei Kang
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ken C Q Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jean M Hébert
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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34
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Mechanistic Target of Rapamycin Regulates the Oligodendrocyte Cytoskeleton during Myelination. J Neurosci 2020; 40:2993-3007. [PMID: 32139584 DOI: 10.1523/jneurosci.1434-18.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 02/23/2020] [Accepted: 02/26/2020] [Indexed: 12/22/2022] Open
Abstract
During differentiation, oligodendrocyte precursor cells (OPCs) extend a network of processes that make contact with axons and initiate myelination. Recent studies revealed that actin polymerization is required for initiation of myelination whereas actin depolymerization promotes myelin wrapping. Here, we used primary OPCs in culture isolated from neonatal rat cortices of both sexes and young male and female mice with oligodendrocyte-specific deletion of mechanistic target of rapamycin (mTOR) to demonstrate that mTOR regulates expression of specific cytoskeletal targets and actin reorganization in oligodendrocytes during developmental myelination. Loss or inhibition of mTOR reduced expression of profilin2 and ARPC3, actin polymerizing factors, and elevated levels of active cofilin, which mediates actin depolymerization. The deficits in actin polymerization were revealed in reduced phalloidin and deficits in oligodendrocyte cellular branching complexity at the peak of morphologic differentiation and a delay in initiation of myelination. We further show a critical role for mTOR in expression and localization of myelin basic protein (Mbp) mRNA and MBP protein to the cellular processes where it is necessary at the myelin membrane for axon wrapping. Mbp mRNA transport deficits were confirmed by single molecule RNA FISH. Moreover, expression of the kinesin family member 1B, an Mbp mRNA transport protein, was reduced in CC1+ cells in the mTOR cKO and in mTOR inhibited oligodendrocytes undergoing differentiation in vitro These data support the conclusion that mTOR regulates both initiation of myelination and axon wrapping by targeting cytoskeletal reorganization and MBP localization to oligodendrocyte processes.SIGNIFICANCE STATEMENT Myelination is essential for normal CNS development and adult axon preservation and function. The mechanistic target of rapamycin (mTOR) signaling pathway has been implicated in promoting CNS myelination; however, there is a gap in our understanding of the mechanisms by which mTOR promotes developmental myelination through regulating specific downstream targets. Here, we present evidence that mTOR promotes the initiation of myelination through regulating specific cytoskeletal targets and cellular process expansion by oligodendrocyte precursor cells as well as expression and cellular localization of myelin basic protein.
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35
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Zhou L, Shao CY, Xie YJ, Wang N, Xu SM, Luo BY, Wu ZY, Ke YH, Qiu M, Shen Y. Gab1 mediates PDGF signaling and is essential to oligodendrocyte differentiation and CNS myelination. eLife 2020; 9:52056. [PMID: 31944179 PMCID: PMC6984811 DOI: 10.7554/elife.52056] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/14/2020] [Indexed: 02/06/2023] Open
Abstract
Oligodendrocytes (OLs) myelinate axons and provide electrical insulation and trophic support for neurons in the central nervous system (CNS). Platelet-derived growth factor (PDGF) is critical for steady-state number and differentiation of oligodendrocyte precursor cells (OPCs), but its downstream targets are unclear. Here, we show for the first time that Gab1, an adaptor protein of receptor tyrosine kinase, is specifically expressed in OL lineage cells and is an essential effector of PDGF signaling in OPCs in mice. Gab1 is downregulated by PDGF stimulation and upregulated during OPC differentiation. Conditional deletions of Gab1 in OLs cause CNS hypomyelination by affecting OPC differentiation. Moreover, Gab1 binds to downstream GSK3β and regulated its activity, and thereby affects the nuclear accumulation of β-catenin and the expression of a number of transcription factors critical to myelination. Our work uncovers a novel downstream target of PDGF signaling, which is essential to OPC differentiation and CNS myelination.
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Affiliation(s)
- Liang Zhou
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Brain Science, Guizhou Institution of Higher Education, Zunyi Medical University, Zunyi, China
| | - Chong-Yu Shao
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ya-Jun Xie
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Na Wang
- School of Medicine, Zhejiang University City College, Hangzhou, China
| | - Si-Min Xu
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ben-Yan Luo
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Yue Hai Ke
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Mengsheng Qiu
- Institute of Life Sciences, Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ying Shen
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
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Thümmler K, Rom E, Zeis T, Lindner M, Brunner S, Cole JJ, Arseni D, Mücklisch S, Edgar JM, Schaeren-Wiemers N, Yayon A, Linington C. Polarizing receptor activation dissociates fibroblast growth factor 2 mediated inhibition of myelination from its neuroprotective potential. Acta Neuropathol Commun 2019; 7:212. [PMID: 31856924 PMCID: PMC6923900 DOI: 10.1186/s40478-019-0864-6] [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: 10/28/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023] Open
Abstract
Fibroblast growth factor (FGF) signaling contributes to failure of remyelination in multiple sclerosis, but targeting this therapeutically is complicated by its functional pleiotropy. We now identify FGF2 as a factor up-regulated by astrocytes in active inflammatory lesions that disrupts myelination via FGF receptor 2 (FGFR2) mediated activation of Wingless (Wnt) signaling; pharmacological inhibition of Wnt being sufficient to abrogate inhibition of myelination by FGF2 in tissue culture. Using a novel FGFR1-selective agonist (F2 V2) generated by deleting the N-terminal 26 amino acids of FGF2 we demonstrate polarizing signal transduction to favor FGFR1 abrogates FGF mediated inhibition of myelination but retains its ability to induce expression of pro-myelinating and immunomodulatory factors that include Cd93, Lif, Il11, Hbegf, Cxcl1 and Timp1. Our data provide new insights into the mechanistic basis of remyelination failure in MS and identify selective activation of FGFR1 as a novel strategy to induce a neuroprotective signaling environment in multiple sclerosis and other neurological diseases.
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37
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Combinatory Multifactor Treatment Effects on Primary Nanofiber Oligodendrocyte Cultures. Cells 2019; 8:cells8111422. [PMID: 31726669 PMCID: PMC6912369 DOI: 10.3390/cells8111422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/29/2019] [Accepted: 11/05/2019] [Indexed: 11/16/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system. Neurological deficits are attributed to inflammatory demyelination, which compromises axonal function and survival. These are mitigated in experimental models by rapid and often complete remyelination of affected axons, but in MS this endogenous repair mechanism frequently fails, leaving axons increasingly vulnerable to the detrimental effects of inflammatory and metabolic stress. Understanding the molecular basis of remyelination and remyelination failure is essential to develop improved therapies for this devastating disease. However, recent studies suggest that this is not due to a single dominant mechanism, but rather represents the biological outcome of multiple changes in the lesion microenvironment that combine to disrupt oligodendrocyte differentiation. This identifies a pressing need to develop technical platforms to investigate combinatory and/or synergistic effects of factors differentially expressed in MS lesions on oligodendrocyte proliferation and differentiation. Here we describe protocols using primary oligodendrocyte cultures from Bl6 mice on 384-well nanofiber plates to model changes affecting oligodendrogenesis and differentiation in the complex signaling environment associated with multiple sclerosis lesions. Using platelet-derived growth factor (PDGF–AA), fibroblast growth factor 2 (FGF2), bone morphogenetic protein 2 (BMP2) and bone morphogenetic protein 4 (BMP4) as representative targets, we demonstrate that we can assess their combinatory effects across a wide range of concentrations in a single experiment. This in vitro model is ideal for assessing the combinatory effects of changes in availability of multiple factors, thus more closely modelling the situation in vivo and furthering high-throughput screening possibilities.
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38
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Furusho M, Ishii A, Hebert JM, Bansal R. Developmental stage-specific role of Frs adapters as mediators of FGF receptor signaling in the oligodendrocyte lineage cells. Glia 2019; 68:617-630. [PMID: 31670856 DOI: 10.1002/glia.23743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/16/2019] [Accepted: 10/12/2019] [Indexed: 11/12/2022]
Abstract
FGF signaling is important for numerous cellular processes and produces diverse cellular responses. Our recent studies using mice conditionally lacking FGF-Receptor-1 (Fgfr1) or Fgfr2 during different stages of myelinogenesis revealed that Fgfr signaling is first required embryonically for the specification of oligodendrocyte progenitors (OPCs) and then later postnatally for the growth of the myelin sheath during active myelination but not for OPC proliferation, differentiation, or ensheathment of axons. What intracellular signal transduction pathways are recruited immediately downstream of Fgfrs and mediate these distinct developmentally regulated stage-specific responses remain unclear. The adapter protein Fibroblast-Growth-Factor-Receptor-Substrate-2 (Frs2) is considered a key immediate downstream target of Fgfrs. Therefore, here, we investigated the in vivo role of Frs adapters in the oligodendrocyte lineage cells, using a novel genetic approach where mice were engineered to disrupt binding of Frs2 to Fgfr1 or Fgfr2, thus specifically uncoupling Frs2 and Fgfr signaling. In addition, we used conditional mutants with complete ablation of Frs2 and Frs3. We found that Frs2 is required for specification of OPCs in the embryonic telencephalon downstream of Fgfr1. In contrast, Frs2 is largely dispensable for transducing Fgfr2-mediated signals for the growth of the myelin sheath during postnatal myelination, implying the potential involvement of other adapters downstream of Fgfr2 for this function. Together, our data demonstrate a developmental stage-specific function of Frs2 in the oligodendrocyte lineage cells. This contextual requirement of adapter proteins, downstream of Fgfrs, could partly explain the distinct responses elicited by the activation of Fgfrs during different stages of myelinogenesis.
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Affiliation(s)
- Miki Furusho
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut
| | - Akihiro Ishii
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut
| | - Jean M Hebert
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Rashmi Bansal
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut
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39
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McCallum-Loudeac J, Anderson G, Wilson MJ. Age and Sex-Related Changes to Gene Expression in the Mouse Spinal Cord. J Mol Neurosci 2019; 69:419-432. [PMID: 31267314 DOI: 10.1007/s12031-019-01371-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023]
Abstract
The spinal cord is essential for neuronal communication between the brain and rest of the body. To gain further insight into the molecular changes underpinning maturation of the mouse spinal cord, we analysed gene expression differences between 4 weeks of age (prior to puberty onset) and adulthood (8 weeks). We found 800 genes were significantly differentially expressed between juvenile and adult spinal cords. Gene ontology analysis revealed an overrepresentation of genes with roles in myelination and signal transduction among others. The expression of a further 19 genes was sexually dimorphic; these included both autosomal and sex-linked genes. Given the presence of steroid hormone receptors in the spinal cord, we also looked at the impact of two major steroid hormones, oestradiol and dihydrotestosterone (DHT) on spinal cord gene expression for selected genes. In gonadectomised male animals, implants with oestradiol and DHT produced significant changes to spinal cord gene expression. This study provides an overview of the global gene expression changes that occur as the spinal cord matures, over a key period of maturation. This confirms that both age and sex are important considerations in studies involving the spinal cord.
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Affiliation(s)
- Jeremy McCallum-Loudeac
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand
| | - Greg Anderson
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand
| | - Megan J Wilson
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand.
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40
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Thotakura S, Basova L, Makarenkova HP. FGF Gradient Controls Boundary Position Between Proliferating and Differentiating Cells and Regulates Lacrimal Gland Growth Dynamics. Front Genet 2019; 10:362. [PMID: 31191595 PMCID: PMC6546953 DOI: 10.3389/fgene.2019.00362] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/04/2019] [Indexed: 12/17/2022] Open
Abstract
Fibroblast growth factor (FGF) signaling plays an important role in controlling cell proliferation, survival, and cell movements during branching morphogenesis of many organs. In mammals branching morphogenesis is primarily regulated by members of the FGF7-subfamily (FGF7 and FGF10), which are expressed in the mesenchyme, and signal to the epithelial cells through the “b” isoform of fibroblast growth factor receptor-2 (FGFR2). Our previous work demonstrated that FGF7 and FGF10 form different gradients in the extracellular matrix (ECM) and induce distinct cellular responses and gene expression profiles in the lacrimal and submandibular glands. The last finding was the most surprising since both FGF7 and FGF10 bind signal most strongly through the same fibroblast growth factor receptor-2b isoform (FGFR2b). Here we revisit this question to gain an explanation of how the different FGFs regulate gene expression. For this purpose, we employed our ex vivo epithelial explant migration assay in which isolated epithelial explants are grown near the FGF loaded beads. We demonstrate that the graded distribution of FGF induces activation of ERK1/2 MAP kinases that define the position of the boundary between proliferating “bud” and differentiating “stalk” cells of growing lacrimal gland epithelium. Moreover, we showed that gene expression profiles of the epithelial explants exposed to distinct FGFs strictly depend on the ratio between “bud” and “stalk” area. Our data also suggests that differentiation of “stalk” and “bud” regions within the epithelial explants is necessary for directional and persistent epithelial migration. Gaining a better understanding of FGF functions is important for development of new approaches to enhance tissue regeneration.
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Affiliation(s)
- Suharika Thotakura
- Department of Molecular Medicine, The Scripps Research Institute, San Diego, CA, United States
| | - Liana Basova
- Department of Molecular Medicine, The Scripps Research Institute, San Diego, CA, United States
| | - Helen P Makarenkova
- Department of Molecular Medicine, The Scripps Research Institute, San Diego, CA, United States
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41
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Ishii A, Furusho M, Macklin W, Bansal R. Independent and cooperative roles of the Mek/ERK1/2-MAPK and PI3K/Akt/mTOR pathways during developmental myelination and in adulthood. Glia 2019; 67:1277-1295. [PMID: 30761608 DOI: 10.1002/glia.23602] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 12/20/2022]
Abstract
Multiple extracellular and intracellular signals regulate the functions of oligodendrocytes as they progress through the complex process of developmental myelination and then maintain a functionally intact myelin sheath throughout adult life, preserving the integrity of the axons. Recent studies suggest that Mek/ERK1/2-MAPK and PI3K/Akt/mTOR intracellular signaling pathways play important, often overlapping roles in the regulation of myelination. However, it remains poorly understood whether they function independently, sequentially, or converge using a common mechanism to facilitate oligodendrocyte differentiation, myelin growth, and maintenance. To address these questions, we analyzed multiple genetically modified mice and asked whether the deficits due to the conditional loss-of-function of ERK1/2 or mTOR could be abrogated by simultaneous constitutive activation of PI3K/Akt or Mek, respectively. From these studies, we concluded that while PI3K/Akt, not Mek/ERK1/2, plays a key role in promoting oligodendrocyte differentiation and timely initiation of myelination through mTORC1 signaling, Mek/ERK1/2-MAPK functions largely independently of mTORC1 to preserve the integrity of the myelinated axons during adulthood. However, to promote the efficient growth of the myelin sheath, these two pathways cooperate with each other converging at the level of mTORC1, both in the context of normal developmental myelination or following forced reactivation of the myelination program during adulthood. Thus, Mek/ERK1/2-MAPK and the PI3K/Akt/mTOR signaling pathways work both independently and cooperatively to maintain a finely tuned, temporally regulated balance as oligodendrocytes progress through different phases of developmental myelination into adulthood. Therapeutic strategies aimed at targeting remyelination in demyelinating diseases are expected to benefit from these findings.
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Affiliation(s)
- Akihiro Ishii
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
| | - Miki Furusho
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
| | - Wendy Macklin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Rashmi Bansal
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut, USA
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42
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Ji XM, Wang SS, Cai XD, Wang XH, Liu QY, Wang P, Cheng ZC, Qian TM. Novel miRNA, miR-sc14, promotes Schwann cell proliferation and migration. Neural Regen Res 2019; 14:1651-1656. [PMID: 31089066 PMCID: PMC6557103 DOI: 10.4103/1673-5374.255996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs refer to a class of endogenous, short non-coding RNAs that mediate numerous biological functions. MicroRNAs regulate various physiological and pathological activities of peripheral nerves, including peripheral nerve repair and regeneration. Previously, using a rat sciatic nerve injury model, we identified many functionally annotated novel microRNAs, including miR-sc14. Here, we used real-time reverse transcription-polymerase chain reaction to examine miR-sc14 expression in rat sciatic nerve stumps. Our results show that miR-sc14 is noticeably altered following sciatic nerve injury, being up-regulated at 1 day and diminished at 7 days. EdU and transwell chamber assay results showed that miR-sc14 mimic promoted proliferation and migration of Schwann cells, while miR-sc14 inhibitor suppressed their proliferation and migration. Additionally, bioinformatic analysis examined potential target genes of miR-sc14, and found that fibroblast growth factor receptor 2 might be a potential target gene. Specifically, our results show changes of miR-sc14 expression in the sciatic nerve of rats at different time points after nerve injury. Appropriately, up-regulation of miR-sc14 promoted proliferation and migration of Schwann cells. Consequently, miR-sc14 may be an intervention target to promote repair of peripheral nerve injury. The study was approved by the Jiangsu Provincial Laboratory Animal Management Committee, China on March 4, 2015 (approval No. 20150304-004).
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Affiliation(s)
- Xi-Meng Ji
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong; Nonnasality Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Shan-Shan Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong; Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Xiao-Dong Cai
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Xing-Hui Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Qian-Yan Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Pan Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Zhang-Chun Cheng
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Tian-Mei Qian
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
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43
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Fletcher JL, Murray SS, Xiao J. Brain-Derived Neurotrophic Factor in Central Nervous System Myelination: A New Mechanism to Promote Myelin Plasticity and Repair. Int J Mol Sci 2018; 19:ijms19124131. [PMID: 30572673 PMCID: PMC6321406 DOI: 10.3390/ijms19124131] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 12/27/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays vitally important roles in neural development and plasticity in both health and disease. Recent studies using mutant mice to selectively manipulate BDNF signalling in desired cell types, in combination with animal models of demyelinating disease, have demonstrated that BDNF not only potentiates normal central nervous system myelination in development but enhances recovery after myelin injury. However, the precise mechanisms by which BDNF enhances myelination in development and repair are unclear. Here, we review some of the recent progress made in understanding the influence BDNF exerts upon the myelinating process during development and after injury, and discuss the cellular and molecular mechanisms underlying its effects. In doing so, we raise new questions for future research.
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Affiliation(s)
- Jessica L Fletcher
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
| | - Simon S Murray
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
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44
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Pepper RE, Pitman KA, Cullen CL, Young KM. How Do Cells of the Oligodendrocyte Lineage Affect Neuronal Circuits to Influence Motor Function, Memory and Mood? Front Cell Neurosci 2018; 12:399. [PMID: 30524235 PMCID: PMC6262292 DOI: 10.3389/fncel.2018.00399] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/17/2018] [Indexed: 12/11/2022] Open
Abstract
Oligodendrocyte progenitor cells (OPCs) are immature cells in the central nervous system (CNS) that can rapidly respond to changes within their environment by modulating their proliferation, motility and differentiation. OPCs differentiate into myelinating oligodendrocytes throughout life, and both cell types have been implicated in maintaining and modulating neuronal function to affect motor performance, cognition and emotional state. However, questions remain about the mechanisms employed by OPCs and oligodendrocytes to regulate circuit function, including whether OPCs can only influence circuits through their generation of new oligodendrocytes, or can play other regulatory roles within the CNS. In this review, we detail the molecular and cellular mechanisms that allow OPCs, newborn oligodendrocytes and pre-existing oligodendrocytes to regulate circuit function and ultimately influence behavioral outcomes.
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Affiliation(s)
- Renee E Pepper
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Kimberley A Pitman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Carlie L Cullen
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
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45
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Blades F, Aprico A, Akkermann R, Ellis S, Binder MD, Kilpatrick TJ. The TAM receptor TYRO3 is a critical regulator of myelin thickness in the central nervous system. Glia 2018; 66:2209-2220. [PMID: 30208252 DOI: 10.1002/glia.23481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 02/03/2023]
Abstract
Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system (CNS). Major deficits arise in MS patients due to an inability to repair damaged myelin sheaths following CNS insult, resulting in prolonged axonal exposure and neurodegeneration. The TAM receptors (Tyro3, Axl, and Mertk) have been implicated in MS susceptibility, demyelination and remyelination. Previously, we have shown that Tyro3 regulates developmental myelination and myelin thickness within the optic nerve and rostral region of the corpus callosum (CC) of adult mice. In this study we have verified and extended our previous findings via a comprehensive analysis of axonal ensheathment and myelin thickness in the CC of unchallenged mice, following demyelination and during myelin repair. We show that the loss of the Tyro3 receptor correlates with significantly thinner myelin sheaths in both unchallenged mice and during remyelination, particularly in larger caliber axons. The hypomyelinated phenotype observed in the absence of Tyro3 occurs independently of any influence upon oligodendrocyte precursor cell (OPC) maturation, or density of oligodendrocytes (OLs) or microglia. Rather, the primary effect of Tyro3 is upon the radial expansion of myelin. The loss of Tyro3 leads to a reduction in the number of myelin lamellae on axons, and is therefore most likely a key component of the regulatory mechanism by which oligodendrocytes match myelin production to axonal diameter.
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Affiliation(s)
- Farrah Blades
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Andrea Aprico
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Rainer Akkermann
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sarah Ellis
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Michele D Binder
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trevor J Kilpatrick
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
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46
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Nicholson M, Wood RJ, Fletcher JL, van den Buuse M, Murray SS, Xiao J. BDNF haploinsufficiency exerts a transient and regionally different influence upon oligodendroglial lineage cells during postnatal development. Mol Cell Neurosci 2018; 90:12-21. [PMID: 29782918 DOI: 10.1016/j.mcn.2018.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 05/09/2018] [Accepted: 05/15/2018] [Indexed: 01/19/2023] Open
Abstract
Brain-Derived Neurotrophic Factor (BDNF) plays important roles in promoting myelination in the developing central nervous system (CNS), however the influence it exerts on oligodendrocyte development in vivo remains unclear. As BDNF knockout mice die in the perinatal period, we undertook a systematic developmental analysis of oligodendroglial lineage cells within multiple CNS regions of BDNF heterozygous (HET) mice. Our data identify that BDNF heterozygosity results in transient reductions in oligodendroglial lineage cell density and progression that are largely restricted to the optic nerve, whereas the corpus callosum, cerebral cortex, basal forebrain and spinal cord white matter tracts are unaffected. In the first two postnatal weeks, BDNF HET mice exhibit reductions in the density of oligodendroglial lineage cells, oligodendrocyte precursor cells (OPCs) and postmitotic oligodendrocytes selectively in the optic nerve, but not in the brain or spinal cord white matter tracts. However, this normalizes later in development. The overall proportion of OPCs and mature oligodendrocytes remains unchanged from P9 to P30 in all CNS regions. This study identifies that BDNF exerts transient effects on oligodendroglial lineage cells selectively in the optic nerve during postnatal development. Taken together, this provides compelling evidence that BDNF haploinsufficiency exerts modest effects upon oligodendroglial cell density and lineage progression in vivo, suggesting its major role is restricted to promoting oligodendrocyte myelination.
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Affiliation(s)
- Madeline Nicholson
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Rhiannon J Wood
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jessica L Fletcher
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Bundoora, Victoria 3086, Australia; Department of Pharmacology, University of Melbourne, Victoria 3010, Australia; The College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Simon S Murray
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria 3010, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria 3010, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3010, Australia.
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47
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R-Ras1 and R-Ras2 Are Essential for Oligodendrocyte Differentiation and Survival for Correct Myelination in the Central Nervous System. J Neurosci 2018; 38:5096-5110. [PMID: 29720552 DOI: 10.1523/jneurosci.3364-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/14/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Rapid and effective neural transmission of information requires correct axonal myelination. Modifications in myelination alter axonal capacity to transmit electric impulses and enable pathological conditions. In the CNS, oligodendrocytes (OLs) myelinate axons, a complex process involving various cellular interactions. However, we know little about the mechanisms that orchestrate correct myelination. Here, we demonstrate that OLs express R-Ras1 and R-Ras2. Using female and male mutant mice to delete these proteins, we found that activation of the PI3K/Akt and Erk1/2-MAPK pathways was weaker in mice lacking one or both of these GTPases, suggesting that both proteins coordinate the activity of these two pathways. Loss of R-Ras1 and/or R-Ras2 diminishes the number of OLs in major myelinated CNS tracts and increases the proportion of immature OLs. In R-Ras1-/- and R-Ras2-/--null mice, OLs show aberrant morphologies and fail to differentiate correctly into myelin-forming phenotypes. The smaller OL population and abnormal OL maturation induce severe hypomyelination, with shorter nodes of Ranvier in R-Ras1-/- and/or R-Ras2-/- mice. These defects explain the slower conduction velocity of myelinated axons that we observed in the absence of R-Ras1 and R-Ras2. Together, these results suggest that R-Ras1 and R-Ras2 are upstream elements that regulate the survival and differentiation of progenitors into OLs through the PI3K/Akt and Erk1/2-MAPK pathways for proper myelination.SIGNIFICANCE STATEMENT In this study, we show that R-Ras1 and R-Ras2 play essential roles in regulating myelination in vivo and control fundamental aspects of oligodendrocyte (OL) survival and differentiation through synergistic activation of PI3K/Akt and Erk1/2-MAPK signaling. Mice lacking R-Ras1 and/or R-Ras2 show a diminished OL population with a higher proportion of immature OLs, explaining the observed hypomyelination in main CNS tracts. In vivo electrophysiology recordings demonstrate a slower conduction velocity of nerve impulses in the absence of R-Ras1 and R-Ras2. Therefore, R-Ras1 and R-Ras2 are essential for proper axonal myelination and accurate neural transmission.
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Terasaki M. Axonal endoplasmic reticulum is very narrow. J Cell Sci 2018; 131:jcs.210450. [PMID: 29361544 DOI: 10.1242/jcs.210450] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/02/2018] [Indexed: 12/20/2022] Open
Abstract
The endoplasmic reticulum (ER) is an interconnected network of tubules and sheets. In most tissues of the body, ER tubules have a diameter of ∼60 nm. Using new methods for serial-section electron microscopy, a distinct class of very narrow, 20- to 30-nm-diameter tubules were found in neurons of both the central and peripheral nervous system. The narrow tubules appear to be the most abundant form of ER in axons, and are also found interspersed in the cell bodies and dendrites. At the site of branch points, there is a small sheet that has a similarly narrow lumen. The narrowness of the ER is likely to be important for the as yet poorly characterized functions of the axonal ER.
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Affiliation(s)
- Mark Terasaki
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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49
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Figlia G, Gerber D, Suter U. Myelination and mTOR. Glia 2017; 66:693-707. [PMID: 29210103 PMCID: PMC5836902 DOI: 10.1002/glia.23273] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/08/2017] [Accepted: 11/17/2017] [Indexed: 02/06/2023]
Abstract
Myelinating cells surround axons to accelerate the propagation of action potentials, to support axonal health, and to refine neural circuits. Myelination is metabolically demanding and, consistent with this notion, mTORC1—a signaling hub coordinating cell metabolism—has been implicated as a key signal for myelination. Here, we will discuss metabolic aspects of myelination, illustrate the main metabolic processes regulated by mTORC1, and review advances on the role of mTORC1 in myelination of the central nervous system and the peripheral nervous system. Recent progress has revealed a complex role of mTORC1 in myelinating cells that includes, besides positive regulation of myelin growth, additional critical functions in the stages preceding active myelination. Based on the available evidence, we will also highlight potential nonoverlapping roles between mTORC1 and its known main upstream pathways PI3K‐Akt, Mek‐Erk1/2, and AMPK in myelinating cells. Finally, we will discuss signals that are already known or hypothesized to be responsible for the regulation of mTORC1 activity in myelinating cells. Myelination is metabolically demanding. The metabolic regulator mTORC1 controls differentiation of myelinating cells and promotes myelin
growth. mTORC1‐independent targets of the PI3K‐Akt and Mek‐Erk1/2 pathways may also be significant in myelination.
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Affiliation(s)
- Gianluca Figlia
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
| | - Daniel Gerber
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
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