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Vega-Torres JD, Ontiveros-Angel P, Terrones E, Stuffle EC, Solak S, Tyner E, Oropeza M, dela Peña I, Obenaus A, Ford BD, Figueroa JD. Short-term exposure to an obesogenic diet during adolescence elicits anxiety-related behavior and neuroinflammation: modulatory effects of exogenous neuregulin-1. Transl Psychiatry 2022; 12:83. [PMID: 35220393 PMCID: PMC8882169 DOI: 10.1038/s41398-022-01788-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/27/2021] [Accepted: 01/07/2022] [Indexed: 11/21/2022] Open
Abstract
Childhood obesity leads to hippocampal atrophy and altered cognition. However, the molecular mechanisms underlying these impairments are poorly understood. The neurotrophic factor neuregulin-1 (NRG1) and its cognate ErbB4 receptor play critical roles in hippocampal maturation and function. This study aimed to determine whether exogenous NRG1 administration reduces hippocampal abnormalities and neuroinflammation in rats exposed to an obesogenic Western-like diet (WD). Lewis rats were randomly divided into four groups (12 rats/group): (1) control diet+vehicle (CDV); (2) CD + NRG1 (CDN) (daily intraperitoneal injections: 5 μg/kg/day; between postnatal day, PND 21-PND 41); (3) WD + VEH (WDV); (4) WD + NRG1 (WDN). Neurobehavioral assessments were performed at PND 43-49. Brains were harvested for MRI and molecular analyses at PND 49. We found that NRG1 administration reduced hippocampal volume (7%) and attenuated hippocampal-dependent cued fear conditioning in CD rats (56%). NRG1 administration reduced PSD-95 protein expression (30%) and selectively reduced hippocampal cytokine levels (IL-33, GM-CSF, CCL-2, IFN-γ) while significantly impacting microglia morphology (increased span ratio and reduced circularity). WD rats exhibited reduced right hippocampal volume (7%), altered microglia morphology (reduced density and increased lacunarity), and increased levels of cytokines implicated in neuroinflammation (IL-1α, TNF-α, IL-6). Notably, NRG1 synergized with the WD to increase hippocampal ErbB4 phosphorylation and the tumor necrosis alpha converting enzyme (TACE/ADAM17) protein levels. Although the results did not provide sufficient evidence to conclude that exogenous NRG1 administration is beneficial to alleviate obesity-related outcomes in adolescent rats, we identified a potential novel interaction between obesogenic diet exposure and TACE/ADAM17-NRG1-ErbB4 signaling during hippocampal maturation. Our results indicate that supraoptimal ErbB4 activities may contribute to the abnormal hippocampal structure and cognitive vulnerabilities observed in obese individuals.
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Affiliation(s)
- Julio David Vega-Torres
- grid.43582.380000 0000 9852 649XCenter for Health Disparities and Molecular Medicine and Department of Basic Sciences, Physiology Division, Department of Basic Sciences, Loma Linda University Health School of Medicine, Loma Linda, CA USA
| | - Perla Ontiveros-Angel
- grid.43582.380000 0000 9852 649XCenter for Health Disparities and Molecular Medicine and Department of Basic Sciences, Physiology Division, Department of Basic Sciences, Loma Linda University Health School of Medicine, Loma Linda, CA USA
| | - Esmeralda Terrones
- grid.43582.380000 0000 9852 649XCenter for Health Disparities and Molecular Medicine and Department of Basic Sciences, Physiology Division, Department of Basic Sciences, Loma Linda University Health School of Medicine, Loma Linda, CA USA
| | - Erwin C. Stuffle
- grid.43582.380000 0000 9852 649XCenter for Health Disparities and Molecular Medicine and Department of Basic Sciences, Physiology Division, Department of Basic Sciences, Loma Linda University Health School of Medicine, Loma Linda, CA USA
| | - Sara Solak
- grid.43582.380000 0000 9852 649XDepartment of Pharmaceutical and Administrative Sciences, Loma Linda University Health School of Pharmacy, Loma Linda, CA USA
| | - Emma Tyner
- grid.43582.380000 0000 9852 649XDepartment of Pharmaceutical and Administrative Sciences, Loma Linda University Health School of Pharmacy, Loma Linda, CA USA
| | - Marie Oropeza
- grid.43582.380000 0000 9852 649XDepartment of Pharmaceutical and Administrative Sciences, Loma Linda University Health School of Pharmacy, Loma Linda, CA USA
| | - Ike dela Peña
- grid.43582.380000 0000 9852 649XDepartment of Pharmaceutical and Administrative Sciences, Loma Linda University Health School of Pharmacy, Loma Linda, CA USA
| | - Andre Obenaus
- grid.266093.80000 0001 0668 7243Department of Pediatrics, University of California-Irvine, Irvine, CA USA
| | - Byron D. Ford
- grid.266097.c0000 0001 2222 1582Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, CA USA
| | - Johnny D. Figueroa
- grid.43582.380000 0000 9852 649XCenter for Health Disparities and Molecular Medicine and Department of Basic Sciences, Physiology Division, Department of Basic Sciences, Loma Linda University Health School of Medicine, Loma Linda, CA USA
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Liu B, Zhang N, Yang J, Sun W, Zhang R, Zheng X, Wang Z, Siebert HC, Han J. Preparation, Characterization, Evaluation of Neuroprotective Effect, and Related Mechanisms of Phosphatidylserine Emulsion in 5- and 12-Week Old Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:1852-1864. [PMID: 35107277 DOI: 10.1021/acs.jafc.1c07403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phosphatidylserine (PS) improves learning and memory capacity. In this study, PS formulation was optimized by a response surface methodology. Moreover, we found that PS not only functions as a biologically active component in food preparations but also improves the emulsion's physical stability. Our results showed that the PS emulsions are characterized by a smaller particle size, higher ζ-potential (negative), higher viscosity, and lower surface tension and centrifugal stability constants than the emulsion without PS. Furthermore, we explored the neuroprotective effects of PS emulsion and its underlying mechanisms. Treatment with 2% (w/w) PS emulsion for three months enhanced spatial learning and memory in 5- and 12-week old mice in the Morris water maze test. Western-blotting analysis displayed that the 2% (w/w) PS emulsion treated group upregulated BDNF, TrkB, PSD95, mTOR, MBP, and ErbB4 expression in the hippocampus of 5- and 12-week old mice. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed elevated Nrg-1 and ErbB4 mRNA expression in the 2% (w/w) PS emulsion treated groups, and high Nrg-1 and ErbB4 expression levels were associated with better myelination. In conclusion, we reported PS emulsions with high stability and high bioavailability. Meanwhile, 2% (w/w) PS emulsion enhances learning, memory, and myelination in mice by activating the BDNF/TrkB and Nrg-1/ErbB4 signaling.
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Affiliation(s)
- Bingyi Liu
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Ning Zhang
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
- RI-B-NT - Research Institute of Bioinformatics and Nanotechnology, Schauenburgerstr.116, 24118 Kiel, Germany
| | - Junrong Yang
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Wei Sun
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Ruiyan Zhang
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
- RI-B-NT - Research Institute of Bioinformatics and Nanotechnology, Schauenburgerstr.116, 24118 Kiel, Germany
| | - Xuexing Zheng
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, China
| | - Zhengping Wang
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
- Liaocheng High-Tech Biotechnology Co., Ltd., Liaocheng 252059, China
| | - Hans-Christian Siebert
- RI-B-NT - Research Institute of Bioinformatics and Nanotechnology, Schauenburgerstr.116, 24118 Kiel, Germany
| | - Jun Han
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
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3
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Mòdol-Caballero G, García-Lareu B, Herrando-Grabulosa M, Verdés S, López-Vales R, Pagès G, Chillón M, Navarro X, Bosch A. Specific Expression of Glial-Derived Neurotrophic Factor in Muscles as Gene Therapy Strategy for Amyotrophic Lateral Sclerosis. Neurotherapeutics 2021; 18:1113-1126. [PMID: 33786805 PMCID: PMC8423878 DOI: 10.1007/s13311-021-01025-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2021] [Indexed: 12/11/2022] Open
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is a powerful neuroprotective growth factor. However, systemic or intrathecal administration of GDNF is associated with side effects. Here, we aimed to avoid this by restricting the transgene expression to the skeletal muscle by gene therapy. To specifically target most skeletal muscles in the mouse model of amyotrophic lateral sclerosis (ALS), SOD1G93A transgenic mice were intravenously injected with adeno-associated vectors coding for GDNF under the control of the desmin promoter. Treated and control SOD1G93A mice were evaluated by rotarod and nerve conduction tests from 8 to 20 weeks of age, and then histological and molecular analyses were performed. Muscle-specific GDNF expression delayed the progression of the disease in SOD1G93A female and male mice by preserving the neuromuscular function; increasing the number of innervated neuromuscular junctions, the survival of spinal motoneurons; and reducing glial reactivity in treated SOD1G93A mice. These beneficial actions are attributed to a paracrine protective mechanism from the muscle to the motoneurons by GDNF. Importantly, no adverse secondary effects were detected. These results highlight the potential of muscle GDNF-targeted expression for ALS therapy.
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Affiliation(s)
- Guillem Mòdol-Caballero
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Belén García-Lareu
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mireia Herrando-Grabulosa
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Sergi Verdés
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain
- Unitat Mixta UAB-VHIR, Vall D'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Rubén López-Vales
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Gemma Pagès
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Miguel Chillón
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain
- Unitat Mixta UAB-VHIR, Vall D'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Institut Català de Recerca I Estudis Avançats (ICREA), Barcelona, Spain
| | - Xavier Navarro
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
- Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
| | - Assumpció Bosch
- Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Unitat Mixta UAB-VHIR, Vall D'Hebron Institut de Recerca (VHIR), Barcelona, Spain.
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4
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Wang M, Kleele T, Xiao Y, Plucinska G, Avramopoulos P, Engelhardt S, Schwab MH, Kneussel M, Czopka T, Sherman DL, Brophy PJ, Misgeld T, Brill MS. Completion of neuronal remodeling prompts myelination along developing motor axon branches. J Cell Biol 2021; 220:211755. [PMID: 33538762 PMCID: PMC7868780 DOI: 10.1083/jcb.201911114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 11/20/2020] [Accepted: 01/04/2021] [Indexed: 12/20/2022] Open
Abstract
Neuronal remodeling and myelination are two fundamental processes during neurodevelopment. How they influence each other remains largely unknown, even though their coordinated execution is critical for circuit function and often disrupted in neuropsychiatric disorders. It is unclear whether myelination stabilizes axon branches during remodeling or whether ongoing remodeling delays myelination. By modulating synaptic transmission, cytoskeletal dynamics, and axonal transport in mouse motor axons, we show that local axon remodeling delays myelination onset and node formation. Conversely, glial differentiation does not determine the outcome of axon remodeling. Delayed myelination is not due to a limited supply of structural components of the axon–glial unit but rather is triggered by increased transport of signaling factors that initiate myelination, such as neuregulin. Further, transport of promyelinating signals is regulated via local cytoskeletal maturation related to activity-dependent competition. Our study reveals an axon branch–specific fine-tuning mechanism that locally coordinates axon remodeling and myelination.
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Affiliation(s)
- Mengzhe Wang
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Tatjana Kleele
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Yan Xiao
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Gabriela Plucinska
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Petros Avramopoulos
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Markus H Schwab
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Matthias Kneussel
- University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), Institute for Molecular Neurogenetics, Hamburg, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Monika S Brill
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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5
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Gene therapy for overexpressing Neuregulin 1 type I in skeletal muscles promotes functional improvement in the SOD1 G93A ALS mice. Neurobiol Dis 2020; 137:104793. [PMID: 32032731 DOI: 10.1016/j.nbd.2020.104793] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/10/2020] [Accepted: 02/03/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motoneurons (MNs), with no effective treatment currently available. The molecular mechanisms that are involved in MN death are complex and not fully understood, with partial contributions of surrounding glial cells and skeletal muscle to the disease. Neuregulin 1 (NRG1) is a trophic factor highly expressed in MNs and neuromuscular junctions. Recent studies have suggested a crucial role of the isoform I (NRG1-I) in the collateral reinnervation process in skeletal muscle, and NRG1-III in the preservation of MNs in the spinal cord, opening a window for developing novel therapies for neuromuscular diseases like ALS. In this study, we overexpressed NRG1-I widely in the skeletal muscles of the SOD1G93A transgenic mouse. The results show that NRG1 gene therapy activated the survival pathways in muscle and spinal cord, increasing the number of surviving MNs and neuromuscular junctions and reducing the astroglial reactivity in the spinal cord of the treated SOD1G93A mice. Furthermore, NRG1-I overexpression preserved motor function and delayed the onset of clinical disease. In summary, our data indicates that NRG1 plays an important role on MN survival and muscle innervation in ALS, and that viral-mediated overexpression of NRG1 isoforms may be considered as a promising approach for ALS treatment.
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6
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Lee YI. Developmental neuromuscular synapse elimination: Activity-dependence and potential downstream effector mechanisms. Neurosci Lett 2019; 718:134724. [PMID: 31877335 DOI: 10.1016/j.neulet.2019.134724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 12/12/2022]
Abstract
Synaptic connections initially formed during nervous system development undergo a significant transformation during nervous system maturation. Such maturation is essential for the proper architecture and function of the nervous system. Developmental synaptic transformation includes "synapse elimination," a process in which multiple immature presynaptic inputs converge at and compete for control of a common postsynaptic target. This developmental synaptic remodeling is best understood at mammalian neuromuscular junctions. It is well established that neuromuscular activity provides the impetus for the pruning of redundant motor axon inputs. Despite the dominant influence neuromuscular activity exerts on developmental synapse elimination, however, the downstream mechanisms of neuromuscular activity that affect synapse elimination remain poorly understood. Conversely, although several cellular and molecular effector mechanisms are known to impact synapse elimination, it is unclear whether they are modulated by neuromuscular activity. This review discusses how the motor neurons, synaptic glia and muscle fibers each contributes to the developmental phenomenon, and speculates how neuromuscular activity may modulate these contributions.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
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Barrenschee M, Cossais F, Böttner M, Egberts JH, Becker T, Wedel T. Impaired Expression of Neuregulin 1 and Nicotinic Acetylcholine Receptor β4 Subunit in Diverticular Disease. Front Cell Neurosci 2019; 13:563. [PMID: 31920561 PMCID: PMC6930903 DOI: 10.3389/fncel.2019.00563] [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: 07/09/2019] [Accepted: 12/05/2019] [Indexed: 12/15/2022] Open
Abstract
Neuregulin 1 (NRG1) regulates the expression of the nicotinic acetylcholine receptor (nAChR) and is suggested to promote the survival and maintenance of the enteric nervous system (ENS), since deficiency of its corresponding receptor complex ErbB2/ErbB3 leads to postnatal colonic aganglionosis. As diverticular disease (DD) is associated with intestinal hypoganglionosis, the NRG1-ErbB2/ErbB3 system and the nAChR were studied in patients with DD and controls. Samples of tunica muscularis of the sigmoid colon from patients with DD (n = 8) and controls (n = 11) were assessed for mRNA expression of NRG1, ErbB2, and ErbB3 and the nAChR subunits α3, α5, α7, β2, and β4. Site-specific gene expression levels of the NRG1-ErbB2/3 system were determined in myenteric ganglia harvested by laser microdissection (LMD). Localization studies were performed by immunohistochemistry for the NRG1-ErbB2/3 system and nAChR subunit β4. Rat enteric nerve cell cultures were stimulated with NRG1 or glial-cell line derived neurotrophic factor (GDNF) for 6 days and mRNA expression of the aforementioned nAchR was measured. NRG1, ErbB3, and nAChR subunit β4 expression was significantly down-regulated in both the tunica muscularis and myenteric ganglia of patients with DD compared to controls, whereas mRNA expression of ErbB3 and nAChR subunits β2, α3, α5, and α7 remained unaltered. NRG1, ErbB3, and nAChR subunit β4 immunoreactive signals were reduced in neuronal somata and the neuropil of myenteric ganglia from patients with DD compared to control. nAChR subunit β4 exhibited also weaker immunoreactive signals in the tunica muscularis of patients with DD. NRG1 treatment but not GDNF treatment of enteric nerve cell cultures significantly enhanced mRNA expression of nAchR β4. The down-regulation of NRG1 and ErbB3 in myenteric ganglia of patients with DD supports the hypothesis that intestinal hypoganglionosis observed in DD may be attributed to a lack of neurotrophic factors. Regulation of nAChR subunit β4 by NRG1 and decreased nAChR β4 in patients with DD provide evidence that a lack of NRG1 may affect the composition of enteric neurotransmitter receptor subunits thus contributing to the intestinal motility disorders previously reported in DD.
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Affiliation(s)
- Martina Barrenschee
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts University of Kiel, Kiel, Germany
| | - François Cossais
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Martina Böttner
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Jan-Hendrik Egberts
- Department of General, Visceral-, Thoracic-, Transplantation-, and Pediatric Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Thomas Becker
- Department of General, Visceral-, Thoracic-, Transplantation-, and Pediatric Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Thilo Wedel
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts University of Kiel, Kiel, Germany
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8
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Kataria H, Alizadeh A, Karimi-Abdolrezaee S. Neuregulin-1/ErbB network: An emerging modulator of nervous system injury and repair. Prog Neurobiol 2019; 180:101643. [PMID: 31229498 DOI: 10.1016/j.pneurobio.2019.101643] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/20/2022]
Abstract
Neuregulin-1 (Nrg-1) is a member of the Neuregulin family of growth factors with essential roles in the developing and adult nervous system. Six different types of Nrg-1 (Nrg-1 type I-VI) and over 30 isoforms have been discovered; however, their specific roles are not fully determined. Nrg-1 signals through a complex network of protein-tyrosine kinase receptors, ErbB2, ErbB3, ErbB4 and multiple intracellular pathways. Genetic and pharmacological studies of Nrg-1 and ErbB receptors have identified a critical role for Nrg-1/ErbB network in neurodevelopment including neuronal migration, neural differentiation, myelination as well as formation of synapses and neuromuscular junctions. Nrg-1 signaling is best known for its characterized role in development and repair of the peripheral nervous system (PNS) due to its essential role in Schwann cell development, survival and myelination. However, our knowledge of the impact of Nrg-1/ErbB on the central nervous system (CNS) has emerged in recent years. Ongoing efforts have uncovered a multi-faceted role for Nrg-1 in regulating CNS injury and repair processes. In this review, we provide a timely overview of the most recent updates on Nrg-1 signaling and its role in nervous system injury and diseases. We will specifically highlight the emerging role of Nrg-1 in modulating the glial and immune responses and its capacity to foster neuroprotection and remyelination in CNS injury. Nrg-1/ErbB network is a key regulatory pathway in the developing nervous system; therefore, unraveling its role in neuropathology and repair can aid in development of new therapeutic approaches for nervous system injuries and associated disorders.
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Affiliation(s)
- Hardeep Kataria
- Department of Physiology and Pathophysiology, Regenerative Medicine Program, Spinal Cord Research Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Arsalan Alizadeh
- Department of Physiology and Pathophysiology, Regenerative Medicine Program, Spinal Cord Research Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, Regenerative Medicine Program, Spinal Cord Research Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
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9
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Lee YI, Thompson WJ, Harlow ML. Schwann cells participate in synapse elimination at the developing neuromuscular junction. Curr Opin Neurobiol 2017; 47:176-181. [PMID: 29121585 PMCID: PMC5732880 DOI: 10.1016/j.conb.2017.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022]
Abstract
During the initial stages of innervation of developing skeletal muscles, the terminal branches of axons from multiple motor neurons form neuromuscular junctions (NMJs) on a small region of each muscle fiber, the motor endplate. Subsequently, the number of axonal inputs at the endplate region is reduced so that, at maturity, each muscle fiber is innervated by the terminals of a single motor neuron. The Schwann cells associated with the axon terminals are involved in the removal of these synapses but do not select the axon that is ultimately retained on each fiber. Schwann cells perform this function by disconnecting terminal branches from the myofiber surface and by attacking them phagocytically. Here we discuss how this behavior is regulated and argue that such regulation is not unique to development of neuromuscular innervation but is also expressed in the response of the mature NMJ to various manipulations and pathologies.
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Affiliation(s)
- Young Il Lee
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States.
| | - Wesley J Thompson
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States; University of Texas (adjunct), Department of Neuroscience, Austin, TX 78712, United States
| | - Mark L Harlow
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States
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10
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Tomàs J, Garcia N, Lanuza MA, Santafé MM, Tomàs M, Nadal L, Hurtado E, Simó A, Cilleros V. Presynaptic Membrane Receptors Modulate ACh Release, Axonal Competition and Synapse Elimination during Neuromuscular Junction Development. Front Mol Neurosci 2017; 10:132. [PMID: 28559796 PMCID: PMC5432534 DOI: 10.3389/fnmol.2017.00132] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/20/2017] [Indexed: 12/17/2022] Open
Abstract
During the histogenesis of the nervous system a lush production of neurons, which establish an excessive number of synapses, is followed by a drop in both neurons and synaptic contacts as maturation proceeds. Hebbian competition between axons with different activities leads to the loss of roughly half of the neurons initially produced so connectivity is refined and specificity gained. The skeletal muscle fibers in the newborn neuromuscular junction (NMJ) are polyinnervated but by the end of the competition, 2 weeks later, the NMJ are innervated by only one axon. This peripheral synapse has long been used as a convenient model for synapse development. In the last few years, we have studied transmitter release and the local involvement of the presynaptic muscarinic acetylcholine autoreceptors (mAChR), adenosine autoreceptors (AR) and trophic factor receptors (TFR, for neurotrophins and trophic cytokines) during the development of NMJ and in the adult. This review article brings together previously published data and proposes a molecular background for developmental axonal competition and loss. At the end of the first week postnatal, these receptors modulate transmitter release in the various nerve terminals on polyinnervated NMJ and contribute to axonal competition and synapse elimination.
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Affiliation(s)
- Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Manel M Santafé
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Laura Nadal
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Erica Hurtado
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Anna Simó
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Víctor Cilleros
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
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Wang J, Song F, Loeb JA. Neuregulin1 fine-tunes pre-, post-, and perisynaptic neuromuscular junction development. Dev Dyn 2017; 246:368-380. [PMID: 28245533 DOI: 10.1002/dvdy.24494] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Neuromuscular junction (NMJ) development is a multistep process mediated by coordinated interactions between the nerve terminal, target muscle, and perisynaptic Schwann cell that require constant back-and-forth communication. Retrograde and anterograde growth and differentiation factors have been postulated to participate in this communication. While neuregulin1 (NRG1) has been shown to be potent anterograde signal that activates acetylcholine receptor (AChR) transcription and clustering in vitro, its roles in NMJ development in vivo remain elusive. RESULTS Using the model of chicken embryo, we measured the effects of NRG1 signaling during NMJ development in ovo using quantitative, sequential measures of AChR cluster size and density, pre- and postsynaptic apposition, and the alignment of perisynaptic Schwann cells. Using in ovo electroporation at early stages and a targeted soluble neuregulin antagonist through all developmental stages, we found soluble NRG1 regulates AChR cluster density and size at the earliest stage prior to nerve-AChR cluster contact. Once the nerve contacts with muscle AChRs, NRG1 has pronounced effects on presynaptic specialization and on the alignment of perisynaptic Schwann cells at endplates. CONCLUSION These findings suggest that, while NRG1 may not be critical for overall development, it appears to be important in fine-tuning pre-, post-, and perisynaptic development of the NMJ. Developmental Dynamics 246:368-380, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jiajing Wang
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, Michigan
| | - Fei Song
- Department of Neurology and Rehabilitation, The University of Illinois at Chicago, Chicago, Illinois
| | - Jeffrey A Loeb
- Department of Neurology and Rehabilitation, The University of Illinois at Chicago, Chicago, Illinois
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Nadal L, Garcia N, Hurtado E, Simó A, Tomàs M, Lanuza MA, Santafé M, Tomàs J. Presynaptic muscarinic acetylcholine autoreceptors (M1, M2 and M4 subtypes), adenosine receptors (A1 and A2A) and tropomyosin-related kinase B receptor (TrkB) modulate the developmental synapse elimination process at the neuromuscular junction. Mol Brain 2016; 9:67. [PMID: 27339059 PMCID: PMC4917939 DOI: 10.1186/s13041-016-0248-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/15/2016] [Indexed: 01/23/2023] Open
Abstract
Background The development of the nervous system involves an initially exuberant production of neurons that make an excessive number of synaptic contacts. The initial overproduction of synapses promotes connectivity. Hebbian competition between axons with different activities (the least active are punished) leads to the loss of roughly half of the overproduced elements and this refines connectivity and increases specificity. The neuromuscular junction is innervated by a single axon at the end of the synapse elimination process and, because of its relative simplicity, has long been used as a model for studying the general principles of synapse development. The involvement of the presynaptic muscarinic ACh autoreceptors may allow for the direct competitive interaction between nerve endings through differential activity-dependent acetylcholine release in the synaptic cleft. Then, the most active ending may directly punish the less active ones. Our previous results indicate the existence in the weakest axons on the polyinnervated neonatal NMJ of an ACh release inhibition mechanism based on mAChR coupled to protein kinase C and voltage-dependent calcium channels. We suggest that this mechanism plays a role in the elimination of redundant neonatal synapses. Results Here we used confocal microscopy and quantitative morphological analysis to count the number of brightly fluorescent axons per endplate in P7, P9 and P15 transgenic B6.Cg-Tg (Thy1-YFP)16 Jrs/J mice. We investigate the involvement of individual mAChR M1-, M2- and M4-subtypes in the control of axonal elimination after the Levator auris longus muscle had been exposed to agonist and antagonist in vivo. We also analysed the role of adenosine receptor subtypes (A1 and A2A) and the tropomyosin-related kinase B receptor. The data show that postnatal axonal elimination is a regulated multireceptor mechanism that guaranteed the monoinnervation of the neuromuscular synapses. Conclusion The three receptor sets considered (mAChR, AR and TrkB receptors) intervene in modulating the conditions of the competition between nerve endings, possibly helping to determine the winner or the lossers but, thereafter, the final elimination would occur with some autonomy and independently of postsynaptic maturation.
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Affiliation(s)
- Laura Nadal
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain.
| | - Erica Hurtado
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Anna Simó
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Manel Santafé
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain
| | - Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHN): Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer St Llorenç num 21, 43201, Reus, Spain.
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Neuregulin1 displayed on motor axons regulates terminal Schwann cell-mediated synapse elimination at developing neuromuscular junctions. Proc Natl Acad Sci U S A 2016; 113:E479-87. [PMID: 26755586 DOI: 10.1073/pnas.1519156113] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Synaptic connections in the nervous system are rearranged during development and in adulthood as a feature of growth, plasticity, aging, and disease. Glia are implicated as active participants in these changes. Here we investigated a signal that controls the participation of peripheral glia, the terminal Schwann cells (SCs), at the neuromuscular junction (NMJ) in mice. Transgenic manipulation of the levels of membrane-tethered neuregulin1 (NRG1-III), a potent activator of SCs normally presented on motor axons, alters the rate of loss of motor inputs at NMJs during developmental synapse elimination. In addition, NMJs of adult transgenic mice that expressed excess axonal NRG1-III exhibited continued remodeling, in contrast to the more stable morphologies of controls. In fact, synaptic SCs of these adult mice with NRG1-III overexpression exhibited behaviors evident in wild type neonates during synapse elimination, including an affinity for the postsynaptic myofiber surface and phagocytosis of nerve terminals. Given that levels of NRG1-III expression normally peak during the period of synapse elimination, our findings identify axon-tethered NRG1 as a molecular determinant for SC-driven neuromuscular synaptic plasticity.
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Barrenschee M, Lange C, Cossais F, Egberts JH, Becker T, Wedel T, Böttner M. Expression and function of Neuregulin 1 and its signaling system ERBB2/3 in the enteric nervous system. Front Cell Neurosci 2015; 9:360. [PMID: 26441531 PMCID: PMC4585281 DOI: 10.3389/fncel.2015.00360] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/28/2015] [Indexed: 12/12/2022] Open
Abstract
Neuregulin 1 (NRG1) is suggested to promote the survival and maintenance of the enteric nervous system (ENS). As deficiency in its corresponding receptor signaling complex ERBB2/ERBB3 leads to postnatal colonic hypo/aganglionosis we assessed the distributional and expressional pattern of the NRG1-ERBB2/ERBB3 system in the human colon and explored the neurotrophic capacity of NRG1 on cultured enteric neurons. Site-specific mRNA expression of the NRG1-ERBB2/3 system was determined in microdissected samples harvested from enteric musculature and ganglia. Localization of NRG1, ERBB2 and ERBB3 was determined by dual-label-immunohistochemistry using pan-neuronal and pan-glial markers. Morphometric analysis was performed on NRG1-stimulated rat enteric nerve cultures to evaluate neurotrophic effects. mRNA expression of the NRG1-ERBB2/3 system was determined by qPCR. Co-localization of NRG1 with neuronal or synaptic markers was analyzed in enteric nerve cultures stimulated with glial cell line-derived neurotrophic factor (GDNF). The NRG1 system was expressed in both neurons and glial cells of enteric ganglia and in nerve fibers. NRG1 significantly enhanced growth parameters in enteric nerve cell cultures and ErB3 mRNA expression was down-regulated upon NRG1 stimulation. GDNF negatively regulates ErbB2 and ErbB3 mRNA expression. The NRG1-ERBB2/3 system is physiologically present in the human ENS and NRG1 acts as a neurotrophic factor for the ENS. The down-regulation of ErbB3/ErbB2 in GDNF stimulated nerve cell cultures points to an interaction of both neurotrophic factors. Thus, the data may provide a basis to assess disturbed signaling components of the NRG1 system in enteric neuropathies.
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Affiliation(s)
- Martina Barrenschee
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Christina Lange
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts-University of Kiel Kiel, Germany
| | - François Cossais
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Jan-Hendrik Egberts
- Department of General, Thoracic, Transplantation and Pediatric Surgery, University Hospital Schleswig-Holstein, Campus Kiel Kiel, Germany
| | - Thomas Becker
- Department of General, Thoracic, Transplantation and Pediatric Surgery, University Hospital Schleswig-Holstein, Campus Kiel Kiel, Germany
| | - Thilo Wedel
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Martina Böttner
- Neurogastroenterology, Institute of Anatomy, Christian-Albrechts-University of Kiel Kiel, Germany
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15
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Kim HG, Cho SM, Lee CK, Jeong SW. Neuregulin 1 as an endogenous regulator of nicotinic acetylcholine receptors in adult major pelvic ganglion neurons. Biochem Biophys Res Commun 2015; 463:632-7. [DOI: 10.1016/j.bbrc.2015.05.113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 05/29/2015] [Indexed: 10/23/2022]
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16
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Wang J, Hmadcha A, Zakarian V, Song F, Loeb JA. Rapid transient isoform-specific neuregulin1 transcription in motor neurons is regulated by neurotrophic factors and axon-target interactions. Mol Cell Neurosci 2015; 68:73-81. [PMID: 25913151 DOI: 10.1016/j.mcn.2015.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 03/16/2015] [Accepted: 04/21/2015] [Indexed: 12/31/2022] Open
Abstract
The neuregulins (NRGs) are a family of alternatively spliced factors that play important roles in nervous system development and disease. In motor neurons, NRG1 expression is regulated by activity and neurotrophic factors, however, little is known about what controls isoform-specific transcription. Here we show that NRG1 expression in the chick embryo increases in motor neurons that have extended their axons and that limb bud ablation before motor axon outgrowth prevents this induction, suggesting a trophic role from the developing limb. Consistently, NRG1 induction after limb bud ablation can be rescued by adding back the neurotrophic factors BDNF and GDNF. Mechanistically, BDNF induces a rapid and transient increase in type I and type III NRG1 mRNAs that peak at 4h in rat embryonic ventral spinal cord cultures. Blocking MAPK or PI3K signaling or blocking transcription with Actinomycin D blocks BDNF induced NRG1 gene induction. BDNF had no effect on mRNA degradation, suggesting that transcriptional activation rather than message stability is important. Furthermore, BDNF activates a reporter construct that includes 700bp upstream of the type I NRG1 start site. Protein synthesis is also required for type I NRG1 mRNA transcription as cycloheximide produced a super-induction of type I, but not type III NRG1 mRNA, possibly through a mechanism involving sustained activation of MAPK and PI3K. These results reveal the existence of highly responsive, transient transcriptional regulatory mechanisms that differentially modulate NRG1 isoform expression as a function of extracellular and intracellular signaling cascades and mediated by neurotrophic factors and axon-target interactions.
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Affiliation(s)
- Jiajing Wang
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Abdelkrim Hmadcha
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; Department of Stem Cells, CABIMER-Fundación Progreso y Salud, Sevilla 41092, Spain
| | - Vaagn Zakarian
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Fei Song
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; Department of Neurology and Rehabilitation, The University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Jeffrey A Loeb
- The Center for Molecular Medicine & Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; Department of Neurology and Rehabilitation, The University of Illinois at Chicago, Chicago, IL 60612, USA.
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Song F, Chiang P, Ravits J, Loeb JA. Activation of microglial neuregulin1 signaling in the corticospinal tracts of ALS patients with upper motor neuron signs. Amyotroph Lateral Scler Frontotemporal Degener 2013; 15:77-83. [DOI: 10.3109/21678421.2013.853802] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Alder J, Kallman S, Palmieri A, Khadim F, Ayer JJ, Kumar S, Tsung K, Grinberg I, Thakker-Varia S. Neuropeptide orphanin FQ inhibits dendritic morphogenesis through activation of RhoA. Dev Neurobiol 2013; 73:769-84. [PMID: 23821558 DOI: 10.1002/dneu.22101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 12/18/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) plays a facilitatory role in neuronal development and promotion of differentiation. Mechanisms that oppose BDNF's stimulatory effects create balance and regulate dendritic growth. However, these mechanisms have not been studied. We have focused our studies on the BDNF-induced neuropeptide OrphaninFQ/ Nociceptin (OFQ); while BDNF is known to enhance synaptic activity, OFQ has opposite effects on activity, learning, and memory. We have now examined whether OFQ provides a balance to the stimulatory effects of BDNF on neuronal differentiation in the hippocampus. Golgi staining in OFQ knockout (KO) mice revealed an increase in primary dendrite length as well as spine density, suggesting that endogenous OFQ inhibits dendritic morphology. We have also used cultured hippocampal neurons to demonstrate that exogenous OFQ has an inhibitory effect on dendritic growth and that the neuropeptide alters the response to BDNF when pre-administered. To determine if BDNF and OFQ act in a feedback loop, we inhibited the actions of the BDNF and OFQ receptors, TrkB and NOP using ANA-12 and NOP KO mice respectively but our data suggest that the two factors do not act in a negative feedback loop. We found that the inhibition of dendritic morphology induced by OFQ is via enhanced RhoA activity. Finally, we have evidence that RhoA activation is required for the inhibitory effects of OFQ on dendritic morphology. Our results reveal basic mechanisms by which neurons not only regulate the formation of proper dendritic growth during development but also control plasticity in the mature nervous system.
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Affiliation(s)
- Janet Alder
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey
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Simpson J, Keefe J, Nishi R. Differential effects of RET and TRKB on axonal branching and survival of parasympathetic neurons. Dev Neurobiol 2012; 73:45-59. [PMID: 22648743 DOI: 10.1002/dneu.22036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 04/11/2012] [Accepted: 05/25/2012] [Indexed: 12/25/2022]
Abstract
Interactions between neurons and their targets of innervation influence many aspects of neural development. To examine how synaptic activity interacts with neurotrophic signaling, we determined the effects of blocking neuromuscular transmission on survival and axonal outgrowth of ciliary neurons from the embryonic chicken ciliary ganglion. Ciliary neurons undergo a period of cell loss due to programmed cell death between embryonic Days (E) 8 and 14 and they innervate the striated muscle of the iris. The nicotinic antagonist d-tubocurarine (dTC) induces an increase in branching measured by counting neurofilament-positive voxels (NF-VU) in the iris between E14-17 while reducing ciliary neuron survival. Blocking ganglionic transmission with dihyro-β-erythroidin and α-methyllycacontine does not mimic dTC. At E8, many trophic factors stimulate neurite outgrowth and branching of neurons placed in cell culture; however, at E13, only GDNF stimulates branching selectively in cultured ciliary neurons. The GDNF-induced branching at E13 could be inhibited by BDNF. Blocking ret signaling in vivo with a dominant negative (dn)ret decreases survival of ciliary and choroid neurons at E14 and prevents dTC induced increases in NF-VU in the iris at E17. Blocking TRKB signaling with dn TRKB increases NF-VU in the iris at E17 and decreases neuronal survival at E17, but not at E14. Thus, RET promotes survival during programmed cell death in the ciliary ganglion and contributes to promoting branching when synaptic transmission is blocked while TRKB inhibits branching and promotes maintenance of neuronal survival. These studies highlight the multifunctional nature of trophic molecule function during neuronal development.
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Affiliation(s)
- Julie Simpson
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
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Greising SM, Gransee HM, Mantilla CB, Sieck GC. Systems biology of skeletal muscle: fiber type as an organizing principle. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 4:457-73. [PMID: 22811254 DOI: 10.1002/wsbm.1184] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Skeletal muscle force generation and contraction are fundamental to countless aspects of human life. The complexity of skeletal muscle physiology is simplified by fiber type classification where differences are observed from neuromuscular transmission to release of intracellular Ca(2+) from the sarcoplasmic reticulum and the resulting recruitment and cycling of cross-bridges. This review uses fiber type classification as an organizing and simplifying principle to explore the complex interactions between the major proteins involved in muscle force generation and contraction.
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Affiliation(s)
- Sarah M Greising
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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Abstract
The neuregulin (NRG) family of trophic factors is present in the central and peripheral nervous systems and participates in the survival, proliferation, and differentiation of many different cell types, including motoneurons. NRG1 was first characterized by its role in the formation of the neuromuscular junction, and recently it was shown to play a crucial role in modulating glutamatergic and cholinergic transmission in the central nervous system of adult rats. However, little is known about NRG1's role in adult motor systems. Motoneurons receive dense glutamatergic and cholinergic input. We hypothesized that NRG1 is present at synapses on phrenic motoneurons. Confocal microscopy and 3D reconstruction techniques were used to determine the distribution of NRG1 and its colocalization with these different neurotransmitter systems. We found that NRG1 puncta are present around retrogradely labeled motoneurons and are distributed predominantly at motoneuron somata and primary dendrites. NRG1 is present exclusively at synaptic sites (identified using the presynaptic marker synaptophysin), making up ∼30% of all synapses at phrenic motoneurons. Overall, NRG1 immunoreactivity is found predominantly at cholinergic synapses (75% ± 14% colocalize with the vesicular acetylcholine transporter; VAChT). Nearly all (99% ± 1%) VAChT-immunoreactive synapses expressed NRG1. NRG1 also is present at a subset of glutamatergic synapses expressing the vesicular glutamate transporter (VGLUT) type 2 (∼6%) but not those expressing VGLUT type 1. Overall, 26% ± 6% of NRG1 synapses are VGLUT2 immunoreactive. These findings provide the first evidence suggesting that NRG1 may modulate synaptic activity in adult motor systems.
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Affiliation(s)
- Amine N Issa
- Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Buonanno A. The neuregulin signaling pathway and schizophrenia: from genes to synapses and neural circuits. Brain Res Bull 2010; 83:122-31. [PMID: 20688137 PMCID: PMC2958213 DOI: 10.1016/j.brainresbull.2010.07.012] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 07/14/2010] [Accepted: 07/20/2010] [Indexed: 02/07/2023]
Abstract
Numerous genetic linkage and association studies implicate members of the Neuregulin-ErbB receptor (NRG-ErbB) signaling pathway as schizophrenia "at risk" genes. An emphasis of this review is to propose plausible neurobiological mechanisms, regulated by the Neuregulin-ErbB signaling network, that may be altered in schizophrenia and contribute to its etiology. To this end, the distinct neurotransmitter pathways, neuronal subtypes and neural network systems altered in schizophrenia are initially discussed. Next, the review focuses on the possible significance of genetic studies associating NRG1 and ErbB4 with schizophrenia, in light of the functional role of this signaling pathway in regulating glutamatergic, GABAergic and dopaminergic neurotransmission, as well as modulating synaptic plasticity and gamma oscillations. The importance of restricted ErbB4 receptor expression in GABAergic interneurons is emphasized, particularly their expression at glutamatergic synapses of parvalbumin-positive fast-spiking interneurons where modulation of inhibitory drive could account for the dramatic effects of NRG-ErbB signaling on gamma oscillations and pyramidal neuron output. A case is made for reasons that the NRG-ErbB signaling pathway constitutes a "biologically plausible" system for understanding the pathogenic mechanisms that may underlie the complex array of positive, negative and cognitive deficits associated with schizophrenia during development.
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Affiliation(s)
- Andrés Buonanno
- National Institutes of Health, Eunice Shriver Kennedy NICHD, Section on Molecular Neurobiology, Program of Developmental Neurobiology, 35 Lincoln Drive, Bethesda, MD 20892-3714, USA.
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Age-associated alterations of the neuromuscular junction. Exp Gerontol 2010; 46:193-8. [PMID: 20854887 DOI: 10.1016/j.exger.2010.08.029] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 08/19/2010] [Accepted: 08/27/2010] [Indexed: 01/09/2023]
Abstract
Age-related loss of muscle mass and function greatly affects quality of life in the elderly population. Several hypotheses have been proposed but accumulating evidence point to alterations in neuromuscular system during aging as a key event that leads to functional denervation, muscle wasting, and weakness. Over the past few decades, age-associated degeneration of the neuromuscular junction (NMJ) and its components have been well documented. With advancing age, pre-terminal portions of motor axons exhibit regions of abnormal thinning, distension, and sprouting whereas postsynaptic endplates decrease in size and reduce in number, length, and density of postsynaptic folds. Although the exact underlying mechanisms are still lacking, recent studies provided direct evidence that age-associated increase in oxidative stress plays a crucial role in NMJ degeneration and progression of sarcopenia. Homozygous deletion of an important antioxidant enzyme, Cu,Zn superoxide dismutase (CuZnSOD, SOD1) leads to acceleration of age-dependent muscle atrophy, with a significant NMJ degeneration similar to that seen in old wild-type sarcopenic animals. In this short review, we briefly summarize the current understanding of some of the cellular and molecular changes in the NMJ during aging and suggest a role for oxidative stress and mitochondrial dysfunction in age-related changes in the maintenance of neuromuscular innervation.
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Neddens J, Buonanno A. Selective populations of hippocampal interneurons express ErbB4 and their number and distribution is altered in ErbB4 knockout mice. Hippocampus 2010; 20:724-44. [PMID: 19655320 DOI: 10.1002/hipo.20675] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuregulins (NRGs) are ligands of ErbB receptor tyrosine kinases. The NRG1-ErbB4 pathway has been shown to modulate hippocampal synaptic plasticity and network oscillations in the adult rodent brain. To identify cells that mediate these effects, here we determine the expression pattern of ErbB4 in four functionally distinct classes of interneurons that represent the majority of all inhibitory neurons in the adult hippocampus. On the basis of data from nine mice and 25,000 cells, we show that ErbB4 is expressed in cells that are positive for cholecystokinin (CCK, 54%), parvalbumin (PV, 42%), or neuronal nitric oxide synthase (nNOS, 39%) in a layer-specific and region-specific manner, whereas cells expressing somatostatin (SOM) are rarely immunoreactive for ErbB4 (1%). We next compared the numerical density (cells/mm(3)) and the distribution of interneurons between ErbB4-/- mice and wildtype controls. Based on data from 25 mice and 56,000 cells, we detected reductions of PV-positive and nNOS-positive cells in knockouts (-24% and -27%, respectively) but only a minor reduction of CCK-positive cells; no changes in SOM-positive cells were observed. The overall reduction of interneurons was verified by quantification of GAD67-immunoreactive cells (-24% in ErbB4-/- mice). The reduction of interneurons along the dorsoventral axis was more severe in intermediate and ventral portions than in the dorsal hippocampus, and regional reductions occurred in the CA1-3 regions and subiculum, whereas we found no significant changes in the dentate gyrus (DG). The expression by different populations of interneurons suggests that ErbB4 can modulate several microcircuits within the hippocampus and mediate the previously reported effects of NRG1 on network oscillations and synaptic plasticity. The selective reduction of GABAergic cells in ErbB4-/- mice is consistent with the role of NRG-ErbB4 signaling in the generation and migration of interneurons during development, and with neuronal and behavioral functional deficits in adult ErbB4 knockouts.
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Affiliation(s)
- Jörg Neddens
- National Institutes of Health, Eunice Shriver Kennedy NICHD, Section on Molecular Neurobiology, Bethesda, Maryland 20892-3714, USA.
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25
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Abstract
A critical step in synaptic development is the differentiation of presynaptic and postsynaptic compartments. This complex process is regulated by a variety of secreted factors that serve as synaptic organizers. Specifically, fibroblast growth factors, Wnts, neurotrophic factors and various other intercellular signaling molecules are proposed to regulate presynaptic and/or postsynaptic differentiation. Many of these factors appear to function at both the neuromuscular junction and in the central nervous system, although the specific function of the molecules differs between the two. Here we review secreted molecules that organize the synaptic compartments and discuss how these molecules shape synaptic development, focusing on mammalian in vivo systems. Their critical role in shaping a functional neural circuit is underscored by their possible link to a wide range of neurological and psychiatric disorders both in animal models and by mutations identified in human patients.
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Affiliation(s)
- Erin M Johnson-Venkatesh
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
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26
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Garcia N, Santafe MM, Tomàs M, Lanuza MA, Besalduch N, Tomàs J. Involvement of brain-derived neurotrophic factor (BDNF) in the functional elimination of synaptic contacts at polyinnervated neuromuscular synapses during development. J Neurosci Res 2010; 88:1406-19. [PMID: 20029969 DOI: 10.1002/jnr.22320] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We use immunohistochemistry to describe the localization of brain-derived neurotrophic factor (BDNF) and its receptors trkB and p75(NTR) in the neuromuscular synapses of postnatal rats (P6-P7) during the synapse elimination period. The receptor protein p75(NTR) is present in the nerve terminal, muscle cell and glial Schwann cell whereas BDNF and trkB proteins can be detected mainly in the pre- and postsynaptic elements. Exogenously applied BDNF (10 nM for 3 hr or 50 nM for 1 hr) increases ACh release from singly and dually innervated synapses. This effect may be specific for BDNF because the neurotrophin NT-4 (2-8 nM) does not modulate release at P6-P7. Blocking the receptors trkB and p75(NTR) (with K-252a and anti-p75-192-IgG, respectively) completely abolishes the potentiating effect of exogenous BDNF. In addition, exogenous BDNF transiently recruits functionally depressed silent terminals, and this effect seems to be mediated by trkB. Calcium ions, the L-type voltage-dependent calcium channels and protein kinase C are involved in BDNF-mediated nerve ending recruitment. Blocking experiments suggest that endogenous BDNF could operate through p75(NTR) receptors coupled to potentiate ACh release in all nerve terminals because the anti-p75-192-IgG reduces release. However, blocking the trkB receptor (K-252a) or neutralizing endogenous BDNF with the trkB-IgG fusion protein reveals a trkB-mediated release inhibition on almost mature strong endings in dual junctions. Taken together these results suggest that a BDNF-induced p75(NTR)-mediated ACh release potentiating mechanism and a BDNF-induced trkB-mediated release inhibitory mechanism may contribute to developmental synapse disconnection.
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Affiliation(s)
- N Garcia
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer Sant Llorenç, Spain
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27
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Outcomes of Direct Muscle Neurotization in Pediatric Patients with Facial Paralysis. Plast Reconstr Surg 2009; 124:1486-1498. [DOI: 10.1097/prs.0b013e3181b98924] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Esper RM, Loeb JA. Neurotrophins induce neuregulin release through protein kinase Cdelta activation. J Biol Chem 2009; 284:26251-60. [PMID: 19648576 PMCID: PMC2785313 DOI: 10.1074/jbc.m109.002915] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 07/28/2009] [Indexed: 12/20/2022] Open
Abstract
Proper, graded communication between different cell types is essential for normal development and function. In the nervous system, heart, and for some cancer cells, part of this communication requires signaling by soluble and membrane-bound factors produced by the NRG1 gene. We have previously shown that glial-derived neurotrophic factors activate a rapid, localized release of soluble neuregulin from neuronal axons that can, in turn promote proper axoglial development (Esper, R. M., and Loeb, J. A. (2004) J. Neurosci. 24, 6218-6227). Here we elucidate the mechanism of this localized, regulated release by implicating the delta isoform of protein kinase C (PKC). Blocking the PKC delta isoform with either rottlerin, a selective antagonist, or small interference RNA blocks the regulated release of neuregulin from both transfected cells and primary neuronal cultures. PKC activation also leads to the rapid phosphorylation of the pro-NRG1 cytoplasmic tail on serine residues adjacent to the membrane-spanning segment, that, when mutated markedly reduce the rate of NRG1 activity release. These findings implicate this specific PKC isoform as an important factor for the cleavage and neurotrophin-regulated release of soluble NRG1 forms that have important effects in nervous system development and disease.
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Affiliation(s)
- Raymond M. Esper
- the Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48201
| | - Jeffrey A. Loeb
- From the Department of Neurology and
- the Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48201
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29
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Mantilla CB, Sieck GC. Neuromuscular adaptations to respiratory muscle inactivity. Respir Physiol Neurobiol 2009; 169:133-40. [PMID: 19744580 DOI: 10.1016/j.resp.2009.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 08/30/2009] [Accepted: 09/01/2009] [Indexed: 01/13/2023]
Abstract
Cervical spinal cord injury results in significant functional impairment. It is important to understand the neuroplasticity in response to inactivity of respiratory muscles in order to prevent any associated effects that limit functional recovery. Recent studies have examined the mechanisms involved in inactivity-induced neuroplasticity of diaphragm motor units. Both spinal hemisection at C2 (C2HS) and tetrodotoxin (TTX)-induced phrenic nerve blockade result in diaphragm paralysis and inactivity of axon terminals. However, phrenic motoneurons are inactive with C2HS but remain active after TTX. Diaphragm muscle fibers ipsilateral to C2HS display minimal changes post-injury. Neuromuscular transmission is enhanced following C2HS but impaired following TTX. Synaptic vesicle pool size at diaphragm neuromuscular junctions increases after C2HS, but decreases after TTX. Thus, inactivity-induced neuromuscular plasticity reflects specific adaptations that depend on inactivity at the motoneuron rather than at axon terminals or muscle fibers. These results indicate that neuromuscular transmission and functional properties of diaphragm fibers can be maintained after spinal cord injury, providing a substrate for functional recovery and/or specific therapeutic approaches such as phrenic pacing.
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Affiliation(s)
- Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, United States.
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30
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Fisahn A, Neddens J, Yan L, Buonanno A. Neuregulin-1 modulates hippocampal gamma oscillations: implications for schizophrenia. ACTA ACUST UNITED AC 2008; 19:612-8. [PMID: 18632742 DOI: 10.1093/cercor/bhn107] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alterations in gamma-frequency oscillations are implicated in psychiatric disorders, and polymorphisms in NRG-1 and ERBB4, genes encoding Neuregulin-1 (NRG-1) and one of its receptors, designated ErbB4, are associated with schizophrenia. Here we show that NRG-1 selectively increases the power of kainate-induced, but not carbachol-induced, gamma oscillations in acute hippocampal slices. NRG-1beta is more effective than NRG-1alpha, a splice variant with lower affinity for ErbB receptors, and neither isoform affects the network activity without prior induction of gamma oscillations. NRG-1beta dramatically increases gamma oscillation power in hippocampal slices from both rats (2062 +/- 496%) and mice (710 +/- 299%). These effects of NRG-1beta are blocked by PD158780, a pan-specific antagonist of ErbB receptors, and are mediated specifically via ErbB4 receptors, because mice harboring a targeted mutation of ErbB4 do not respond to NRG-1. Moreover, we demonstrate that 50% of gamma-amino butyric acidergic parvalbumin (PV)-positive interneurons, which heavily contribute to the generation of gamma oscillations, express ErbB4 receptors. Importantly, both the number of PV-immunoreactive interneurons (-31%) and the power of kainate-induced gamma oscillations (-60%) are reduced in ErbB4 knockout mice. This study provides the first plausible link between NRG-1/ErbB4 signaling and rhythmic network activity that may be altered in persons with schizophrenia.
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Affiliation(s)
- André Fisahn
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
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31
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Neuregulin blocks synaptic strengthening after epileptiform activity in the rat hippocampus. Brain Res 2008; 1208:67-73. [PMID: 18387600 DOI: 10.1016/j.brainres.2008.02.045] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 02/09/2008] [Accepted: 02/15/2008] [Indexed: 11/23/2022]
Abstract
Synaptic strengthening produced by epileptiform activity may contribute to seizure progression and cognitive impairment in epilepsy. Agents that limit this form of plasticity may have therapeutic benefit. Neuregulin is an endogenous growth factor that is released at synapses in an activity dependent manner and can suppress long term potentiation (LTP). Alterations in neuregulin signaling have been associated with schizophrenia. A role for neuregulin in epilepsy has not been explored. We used field potential recordings to examine the role of neuregulin in regulating synaptic strengthening following epileptiform activity in hippocampal slices. Neuregulin had no effect on basal synaptic transmission, isolated NMDA field potentials or GABAergic inhibition on CA1 pyramidal neurons. However, it reversed LTP at CA1 synapses. Brief exposure to 10 mM potassium chloride produced epileptiform bursting and potentiation of CA1 synapses and suppressed the subsequent induction of LTP. Neuregulin reversed high K(+)-induced synaptic strengthening, enabling LTP induction after neuregulin washout. In this manner neuregulin preserved the dynamic range of synaptic responses and plasticity after epileptiform activity. These results indicate that LTP and high K(+)-induced synaptic strengthening share a common neuregulin-sensitive mechanism. By opposing synaptic strengthening caused by epileptiform activity, we suggest that neuregulin may reduce the generation and spread of seizures as well as memory deficits associated with epilepsy.
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32
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Calderó J, Tarabal O, Casanovas A, Ciutat D, Casas C, Lladó J, Esquerda JE. Excitotoxic motoneuron disease in chick embryo evolves with autophagic neurodegeneration and deregulation of neuromuscular innervation. J Neurosci Res 2008; 85:2726-40. [PMID: 17243177 DOI: 10.1002/jnr.21174] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the chick embryo, in ovo application of NMDA from embryonic day (E) 5 to E9 results in selective damage to spinal cord motoneurons (MNs) that undergo a long-lasting degenerative process without immediate cell death. This contrasts with a single application of NMDA on E8, or later, which induces massive necrosis of the whole spinal cord. Chronic MN degeneration after NMDA implies transient incompetence to develop programmed cell death, altered protein processing within secretory pathways, and late activation of autophagy. Chronic NMDA treatment also results in an enlargement of thapsigargin-sensitive Ca(2+) stores. In particular MN pools, such as sartorius-innervating MNs, the neuropeptide CGRP is accumulated in somas, peripheral axons and neuromuscular junctions after chronic NMDA treatment, but not in embryos paralyzed by chronic administration of curare. Intramuscular axonal branching is also altered severely after NMDA: it usually increases, but in some cases a marked reduction can also be observed. Moreover, innervated muscle postsynaptic sites increase by NMDA, but to a lesser extent than by curare. Because some of these results show interesting homologies with MN pathology in human sporadic ALS, the model presented here provides a valuable tool for advancing in the understanding of some cellular and molecular processes particularly involved in this disease.
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Affiliation(s)
- Jordi Calderó
- Unitat de Neurobiologia Cellular, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida, Catalonia, Spain
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33
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Ermilov LG, Sieck GC, Zhan WZ, Mantilla CB. Neurotrophins improve synaptic transmission in the adult rodent diaphragm. NEUROPHYSIOLOGY+ 2007. [DOI: 10.1007/s11062-007-0039-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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34
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Hess DM, Scott MO, Potluri S, Pitts EV, Cisterni C, Balice-Gordon RJ. Localization of TrkC to Schwann cells and effects of neurotrophin-3 signaling at neuromuscular synapses. J Comp Neurol 2007; 501:465-82. [PMID: 17278135 DOI: 10.1002/cne.21163] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neurotrophins and their receptors, the Trks, are differentially expressed among the cell types that make up neuromuscular and other synapses, but the function and directionality of neurotrophin signaling at synapses are poorly understood. Here we demonstrate, via immunostaining, Western blotting, and RT-PCR analyses, that TrkC, the receptor for neurotrophin-3 (NT3), is expressed by mouse perisynaptic and myelinating Schwann cells from birth through adulthood and is unaltered after denervation. Analyses of transgenic mice in which the NT3 coding sequence is replaced by lacZ showed that NT3 is expressed in motor neurons and Schwann cells during perinatal development, but not in adult mice. In muscle, NT3 is expressed by intrafusal muscle fibers within spindles, as has been previously reported. Surprisingly, NT3 is also expressed in extrafusal muscle fibers during perinatal life and in adults. Genetic approaches were used to explore the roles of NT3 and TrkC signaling at neuromuscular synapses. Overexpression of NT3 in muscle fibers during development resulted in an increased number of perisynaptic Schwann cells at neuromuscular synapses, without altering synaptic size, suggesting that muscle-derived NT3 might act as a mitogen or trophic factor for Schwann cells. Conditional deletion of NT3 from motor neurons did not alter the number of Schwann cells or other aspects of neuromuscular synaptic structure, suggesting that motor-neuron-derived NT3 is not required for normal development of perisynaptic Schwann cells or synapses. Together, these results demonstrate that NT3 expression is developmentally regulated in skeletal muscle and may modulate the number of Schwann cells at neuromuscular synapses.
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Affiliation(s)
- Darren M Hess
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA
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35
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Todd KJ, Auld DS, Robitaille R. Neurotrophins modulate neuron-glia interactions at a vertebrate synapse. Eur J Neurosci 2007; 25:1287-96. [PMID: 17355253 DOI: 10.1111/j.1460-9568.2007.05385.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neurotrophins are important modulators of synaptic function at both developing and mature synapses in the CNS and PNS. At the neuromuscular junction (NMJ), neurotrophins, as well as perisynaptic Schwann cells (PSCs) are critical for the long-term maintenance and stability of the synapse. Considering this correlation and the acute interactions that occur at the synapse between PSCs and the nerve terminal, we wondered if neurotrophins could also be involved in neuron-glia signalling. To test if neurotrophins were able to signal to PSCs we used brief applications of neurotrophin-3 (NT-3), brain-derived neurotophic factor (BDNF) or nerve growth factor (NGF; 100 ng/mL). Soleus muscles of mice were incubated with the Ca(2+) indicator Fluo-4AM and Ca(2+) responses in PSCs were elicited through nerve stimulation (50 Hz, 30 s). Our results indicate that acute application of both NT-3 and BDNF, but not NGF, increased PSC Ca(2+) responses. Investigation of the mechanisms involved in these increases revealed distinct pathways for BDNF and NT-3. BDNF increased PSC responsiveness through potentiation of ATP responses while NT-3 modulated muscarinic acetylcholine receptor signalling. Using local applications of the neurotrophins, we found that both neurotrophins were able to elicit Ca(2+) responses in PSCs where BDNF used a phospholipase C-inositol 1,4,5-triphosphate (PLC-IP(3)) mechanism, while NT-3 required extracellular Ca(2+). Our results demonstrate a neurotrophin-dependent modulation of neuron-glia signalling through differential mechanisms employed by NT-3 and BDNF. Hence, neurotrophins precisely and differentially regulate PSC functions through modulation of either purinergic or cholinergic signalling pathways.
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Affiliation(s)
- Keith J Todd
- Département de physiologie and Centre de Recherche en Sciences Neurologiques, Faculté de médecine, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montréal, Québec, Canada, H3C 3J7
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36
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Bouwman J, Spijker S, Schut D, Wächtler B, Ylstra B, Smit AB, Verhage M. Reduced expression of neuropeptide genes in a genome-wide screen of a secretion-deficient mouse. J Neurochem 2006; 99:84-96. [PMID: 16987237 DOI: 10.1111/j.1471-4159.2006.04041.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Activity-dependent changes in synapses rely on functional changes in resident proteins and on gene expression. We addressed the relationship between synapse activity and the expression of synaptic genes by comparing RNA levels in the neocortex of normal mice versus secretion-deficient and therefore synaptically silent munc18-1 (mammalian homologue of Caenorhabditis elegans uncoordinated locomotion-18) null mutants, using microarray expression analysis, real-time quantitative PCR and northern blotting. We hypothesized that genes under the control of synaptic activity would be differentially expressed between mutants and controls. We found that few synaptic genes were differentially expressed. However, most neuropeptide genes with detectable expression on the microarray were differentially expressed, being expressed 3-20-fold higher in control cortex. Several other secreted proteins were also differentially expressed, but genes encoding their receptors and many other synaptic components were not. Differential expression was confirmed by real-time quantitative PCR analysis. In situ hybridization indicated that the difference in neuropeptide expression was uniform and not due to the loss of specific cells in the mutant. In primary sensory neurons, which do not depend on synaptic activity for their input, the differential expression of neuropeptides was not observed. These data argue against a general relationship between the activity of synapses and the expression of their resident proteins, but suggest a link between secretion and the expression of genes encoding the secreted products.
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Affiliation(s)
- J Bouwman
- Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam (VUA) and VU Medical Centre (VUmc), Amsterdam, the Netherlands
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37
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Pitts EV, Potluri S, Hess DM, Balice-Gordon RJ. Neurotrophin and Trk-mediated signaling in the neuromuscular system. Int Anesthesiol Clin 2006; 44:21-76. [PMID: 16849956 DOI: 10.1097/00004311-200604420-00004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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38
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Esper RM, Pankonin MS, Loeb JA. Neuregulins: Versatile growth and differentiation factors in nervous system development and human disease. ACTA ACUST UNITED AC 2006; 51:161-75. [PMID: 16412517 DOI: 10.1016/j.brainresrev.2005.11.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 11/02/2005] [Accepted: 11/04/2005] [Indexed: 12/29/2022]
Abstract
The neuregulins are a family of growth and differentiation factors with a wide range of functions in the nervous system. The power and diversity of the neuregulin signaling system comes in part from a large number of alternatively-spliced forms of the NRG1 gene that can produce both soluble and membrane-bound forms. The soluble forms of neuregulin are unique from other factors in that they have a structurally distinct heparin-binding domain that targets and potentiates its actions. In addition, a finely tuned, bidirectional mechanism regulates when and where neuregulin is released from neurons in response to neurotrophic factors produced by both neuronal targets and supporting glial cells. Together, this produces a balanced intercellular signaling system that can be localized to distinct regions for both normal development and maintenance of the mature nervous system. Recent evidence suggests that neuregulin signaling plays important roles in many neurological disorders including multiple sclerosis, traumatic brain and spinal cord injury, peripheral neuropathy, and schizophrenia. Here, we review the basic biology of neuregulins and relate this to research suggesting their involvement with and potential therapeutic uses for neurological disorders.
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Affiliation(s)
- Raymond M Esper
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA
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39
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Patton B, Burgess RW. Synaptogenesis. Dev Neurobiol 2006. [DOI: 10.1007/0-387-28117-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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40
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Lin W, Dominguez B, Yang J, Aryal P, Brandon EP, Gage FH, Lee KF. Neurotransmitter acetylcholine negatively regulates neuromuscular synapse formation by a Cdk5-dependent mechanism. Neuron 2005; 46:569-79. [PMID: 15944126 DOI: 10.1016/j.neuron.2005.04.002] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 12/23/2004] [Accepted: 04/03/2005] [Indexed: 10/25/2022]
Abstract
Synapse formation requires interactions between pre- and postsynaptic cells to establish the connection of a presynaptic nerve terminal with the neurotransmitter receptor-rich postsynaptic apparatus. At developing vertebrate neuromuscular junctions, acetylcholine receptor (AChR) clusters of nascent postsynaptic apparatus are not apposed by presynaptic nerve terminals. Two opposing activities subsequently promote the formation of synapses: positive signals stabilize the innervated AChR clusters, whereas negative signals disperse those that are not innervated. Although the nerve-derived protein agrin has been suggested to be a positive signal, the negative signals remain elusive. Here, we show that cyclin-dependent kinase 5 (Cdk5) is activated by ACh agonists and is required for the ACh agonist-induced dispersion of the AChR clusters that have not been stabilized by agrin. Genetic elimination of Cdk5 or blocking ACh production prevents the dispersion of AChR clusters in agrin mutants. Therefore, we propose that ACh negatively regulates neuromuscular synapse formation through a Cdk5-dependent mechanism.
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Affiliation(s)
- Weichun Lin
- The Salk Institute, La Jolla, California 92037, USA
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41
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Ruiz R, Lin J, Forgie A, Foletti D, Shelton D, Rosenthal A, Tabares L. Treatment with trkC agonist antibodies delays disease progression in neuromuscular degeneration (nmd) mice. Hum Mol Genet 2005; 14:1825-37. [PMID: 15888478 DOI: 10.1093/hmg/ddi189] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a fatal autosomal recessive disorder seen in infants. It is characterized by lower motor neuron degeneration, progressive muscle paralysis and respiratory failure, for which no effective treatment exists. The phenotype of neuromuscular degeneration (nmd) mice closely resembles the human SMARD1. The identification of the mutated mouse gene in nmd mice, Ighmbp2, led to the discovery of mutations of the homologous gene in humans with SMARD1. We have studied the nmd mouse model with in vivo electrophysiological techniques and evaluated the efficacy of Mab2256, a monoclonal antibody with agonist effect on the tyrosine kinase receptor C, trkC, on disease progression in nmd mice. Treatment with Mab2256 resulted in a significant but transient improvement of muscle strength in nmd mice, as well as normalization of the neuromuscular depression during high-frequency nerve stimulation. These results suggest the potential of using monoclonal agonist antibodies for neurotrophin receptors in lower motor neuron diseases such as SMARD1.
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Affiliation(s)
- Rocio Ruiz
- Department of Physiology and Biophysics, School of Medicine, University of Seville, Seville, Spain
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42
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Li Q, Esper RM, Loeb JA. Synergistic effects of neuregulin and agrin on muscle acetylcholine receptor expression. Mol Cell Neurosci 2004; 26:558-69. [PMID: 15276157 DOI: 10.1016/j.mcn.2004.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 04/19/2004] [Accepted: 04/27/2004] [Indexed: 11/24/2022] Open
Abstract
The proper function of neuromuscular junctions requires an extremely high density of acetylcholine receptors (AChRs) that may be achieved from neuron-derived factors including agrin and neuregulin. Here, we show that neuregulin-1 and agrin co-localize at neuromuscular junctions in vivo and form complexes when co-transfected into COS-7 cells. When these COS-7 cells are cultured with myotubes, synergistic effects are observed for AChR clustering, membrane insertion of new AChRs, and induction of AChR mRNA. Even a muscle form of agrin that lacks intrinsic clustering activities by itself, significantly enhances neuregulin-induced clustering and insertion of AChRs. While the heparin-binding (A) domain of agrin is required for agrin localization in the extracellular matrix adjacent to AChR clusters, the heparan sulfate-containing domain of agrin is needed for the synergistic effects and co-localization with neuregulin-1. These results suggest that matrix interactions between exogenously supplied agrin and neuregulin-1 on the muscle surface provide a localized source of signaling factors needed to produce high densities of AChRs at neuromuscular junctions.
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MESH Headings
- Agrin/genetics
- Agrin/metabolism
- Agrin/pharmacology
- Animals
- Avian Proteins
- Binding Sites/genetics
- COS Cells
- Cell Membrane/drug effects
- Cell Membrane/genetics
- Cell Membrane/metabolism
- Chick Embryo
- Coculture Techniques
- Extracellular Matrix/drug effects
- Extracellular Matrix/genetics
- Extracellular Matrix/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/genetics
- Heparin/metabolism
- Heparitin Sulfate/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/embryology
- Muscle, Skeletal/innervation
- Muscle, Skeletal/metabolism
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/pharmacology
- Neuregulin-1
- Neuromuscular Junction/embryology
- Neuromuscular Junction/genetics
- Neuromuscular Junction/metabolism
- Protein Binding/drug effects
- Protein Binding/genetics
- Protein Structure, Tertiary/genetics
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Receptor Aggregation/drug effects
- Receptor Aggregation/genetics
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Transfection
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Affiliation(s)
- Qunfang Li
- Department of Neurology and The Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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43
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Lefebvre JL, Ono F, Puglielli C, Seidner G, Franzini-Armstrong C, Brehm P, Granato M. Increased neuromuscular activity causes axonal defects and muscular degeneration. Development 2004; 131:2605-18. [PMID: 15128655 DOI: 10.1242/dev.01123] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Before establishing terminal synapses with their final muscle targets,migrating motor axons form en passant synaptic contacts with myotomal muscle. Whereas signaling through terminal synapses has been shown to play important roles in pre- and postsynaptic development, little is known about the function of these early en passant synaptic contacts. Here, we show that increased neuromuscular activity through en passant synaptic contacts affects pre- and postsynaptic development. We demonstrate that in zebrafish twistermutants, prolonged neuromuscular transmission causes motor axonal extension and muscular degeneration in a dose-dependent manner. Cloning of twister reveals a novel, dominant gain-of-function mutation in the muscle-specific nicotinic acetylcholine receptor α-subunit, CHRNA1. Moreover, electrophysiological analysis demonstrates that the mutant subunit increases synaptic decay times, thereby prolonging postsynaptic activity. We show that as the first en passant synaptic contacts form, excessive postsynaptic activity in homozygous embryos severely impedes pre- and postsynaptic development, leading to degenerative defects characteristic of the human slow-channel congenital myasthenic syndrome. By contrast, in heterozygous embryos, transient and mild increase in postsynaptic activity does not overtly affect postsynaptic morphology but causes transient axonal defects, suggesting bi-directional communication between motor axons and myotomal muscle. Together, our results provide compelling evidence that during pathfinding, myotomal muscle cells communicate extensively with extending motor axons through en passant synaptic contacts.
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Affiliation(s)
- Julie L Lefebvre
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA
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44
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Hashimoto R, Straub RE, Weickert CS, Hyde TM, Kleinman JE, Weinberger DR. Expression analysis of neuregulin-1 in the dorsolateral prefrontal cortex in schizophrenia. Mol Psychiatry 2004; 9:299-307. [PMID: 14569272 DOI: 10.1038/sj.mp.4001434] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genetic linkage and association have implicated neuregulin-1 (NRG-1) as a schizophrenia susceptibility gene. We measured mRNA expression levels of the three major isoforms of NRG-1 (ie type I, type II, and type III) in the postmortem dorsolateral prefrontal cortex (DLPFC) from matched patients and controls using real-time quantitative RT-PCR. Expression levels of three internal controls-GAPDH, cyclophilin, and beta-actin-were unchanged in schizophrenia, and there were no changes in the absolute levels of the NRG-1 isoforms. However, type I expression normalized by GAPDH levels was significantly increased in schizophrenia DLPFC (by 23%) and positively correlated with antipsychotic medication dosage. Type II/type I and type II/type III ratios were significantly decreased (18 and 23% respectively). There was no effect on the NRG-1 mRNA levels of genotype at two SNPs previously associated with schizophrenia, suggesting that these alleles are not functionally responsible for abnormal NRG-1 expression patterns in patients. Subtle abnormalities in the expression patterns of NRG-1 mRNA isoforms in DLPFC may be associated with schizophrenia.
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Affiliation(s)
- R Hashimoto
- Clinical Brain Disorders Branch, National Institute of Mental Health, Bethesda, MD 20892, USA
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45
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Longart M, Liu Y, Karavanova I, Buonanno A. Neuregulin-2 is developmentally regulated and targeted to dendrites of central neurons. J Comp Neurol 2004; 472:156-72. [PMID: 15048684 DOI: 10.1002/cne.20016] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neuregulin-1 (NRG-1) regulates numerous aspects of neural development and synaptic plasticity; the functions of NRG-2 and NRG-3 are presently unknown. As a first step toward understanding how NRGs contribute to distinct aspects of neural development and function, we characterized their regional and subcellular expression patterns in developing brain. The expression of NRG-1-3 mRNAs was compared postnatally (P0, P7, adult) by using in situ hybridization. NRG-1 expression is highest at birth, whereas NRG-2 mRNA levels increase with development; expression of both genes is restricted to distinct brain regions. In contrast, NRG-3 transcripts are abundant in most brain regions throughout development. NRG-2 antibodies were generated to analyze protein processing, expression, and subcellular distribution. As with NRG-1, the transmembrane NRG-2 proprotein is proteolytically processed in transfected HEK 293 cells and in neural tissues, and its ectodomain is exposed and accumulates on the neuron surface. Despite the structural similarities between NRG-1 and NRG-2, we unexpectedly found that NRG-2 colocalizes with MAP2 in proximal primary dendrites of hippocampal neurons in culture and in vivo, although it is not detectable in axons or in axon terminals. These findings were confirmed with NRG-2 ectodomain antisera and epitope-tagged recombinant protein. In cerebellum, NRG-2 colocalizes with calbindin in proximal dendrites and soma of Purkinje cells. In contrast, NRG-1 is highly expressed in axons of dissociated hippocampal neurons, as well as in somas and dendrites. The distinct temporal, regional, and subcellular expression of NRG-2 suggests its unique and nonredundant role in neural function.
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Affiliation(s)
- Marines Longart
- Section on Molecular Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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46
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Jiang JXS, Choi RCY, Siow NL, Lee HHC, Wan DCC, Tsim KWK. Muscle induces neuronal expression of acetylcholinesterase in neuron-muscle co-culture: transcriptional regulation mediated by cAMP-dependent signaling. J Biol Chem 2003; 278:45435-44. [PMID: 12963741 DOI: 10.1074/jbc.m306320200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presynaptic motor neuron synthesizes and secretes acetylcholinesterase (AChE) at vertebrate neuromuscular junctions. In order to determine the retrograde role of muscle in regulating the expression of AChE in motor neuron, a chimeric co-culture of NG108-15 cell, a cholinergic cell line that resembles motor neuron, with chick myotube was established to mimic the neuromuscular contact in vitro. A DNA construct of human AChE promoter tagged with luciferase (pAChE-Luc) was stably transfected into NG108-15 cells. The co-culture with myotubes robustly stimulated the promoter activity as well as the endogenous expression of AChE in pAChE-Luc stably transfected NG108-15 cells. Muscle extract derived from chick embryos when applied onto pAChE-Luc-expressing NG108-15 cells induced expressions of AChE promoter and endogenous AChE. The cAMP-responsive element mutation on human AChE promoter blocked the muscle-induced AChE transcriptional activity in cultured NG108-15 cells either in co-culturing with myotube or in applying muscle extract. The accumulation of intracellular cAMP and the phosphorylation of cAMP-responsive element-binding protein in cultured NG108-15 cells were stimulated by applied muscle extract. Part of the muscle-induced signaling was mimicked by application of calcitonin gene-related peptide in cultured NG108-15 cells. These results suggest the muscle-induced neuronal AChE expression in the co-culture is mediated by a cAMP-dependent signaling.
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Affiliation(s)
- Joy X S Jiang
- Department of Biology and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong, China
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47
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Wardle RA, Poo MM. Brain-derived neurotrophic factor modulation of GABAergic synapses by postsynaptic regulation of chloride transport. J Neurosci 2003; 23:8722-32. [PMID: 14507972 PMCID: PMC6740427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2003] [Revised: 07/31/2003] [Accepted: 08/12/2003] [Indexed: 04/27/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) potentiates excitatory synapses in a variety of systems by promoting presynaptic transmitter release. The existing evidence indicates that BDNF attenuates inhibitory transmission, but reports differ considerably in their characterization of the effect and proposed mechanisms. We examined the effects of exogenously applied BDNF on EPSCs and IPSCs recorded from functionally identified neurons in dissociated rat hippocampal cultures. When recording from glutamatergic neurons, we found that BDNF exerted differential effects at excitatory versus inhibitory synapses: increasing amplitude of EPSCs but slightly decreasing that of IPSCs. Furthermore, when recording from GABAergic neurons, we found that BDNF increased the IPSC amplitude. That these differential BDNF effects reflect distinct presynaptic and postsynaptic mechanisms was suggested by the BDNF-induced changes in miniature EPSCs and IPSCs. An increased mini-frequency was found at all synapses, indicating elevated presynaptic transmitter secretion; a change in the amplitude of mini-IPSCs was found at GABAergic cells, suggesting postsynaptic modulation of GABA responses. Selective postsynaptic mechanisms were further examined by comparing the effect of BDNF on GABA-induced currents recorded from glutamatergic versus GABAergic cells. For GABAergic but not glutamatergic postsynaptic cells, BDNF induced a shift in the reversal potential (EIPSC) toward more positive levels, hence reducing the inhibitory action of IPSCs. This BDNF-induced effect correlates with the existing level of furosemide-sensitive K+-Cl- transport activity in the postsynaptic cell. Thus, BDNF may decrease the efficacy of inhibitory transmission by acute postsynaptic downregulation of Cl- transport, in addition to its well known presynaptic effect.
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Affiliation(s)
- Rinda A Wardle
- Division of Neurobiology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, USA
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48
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Kim JY, Sun Q, Oglesbee M, Yoon SO. The role of ErbB2 signaling in the onset of terminal differentiation of oligodendrocytes in vivo. J Neurosci 2003; 23:5561-71. [PMID: 12843257 PMCID: PMC6741253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
The knock-out analyses of neuregulin and its receptors have indicated that they play essential roles in Schwann cell development. However, the role they play in oligodendrocyte development in vivo has remained unclear, because such knock-out animals die before CNS myelination begins. We examined the role of neuregulin signaling in the CNS by generating transgenic mice that express a dominant-negative mutant of the ErbB2 receptor among oligodendrocytes, using an MBP promoter. The transgenic mice exhibited widespread hypomyelination, resulting from a reduction in oligodendrocyte differentiation. The number of progenitors was conversely increased in the transgenic mice. We report that a reduction in oligodendrocyte differentiation is attributed in part to apoptosis of oligodendrocyte progenitors as they exit the cell cycle. A significant reduction in the number of p27+ oligodendrocyte precursors in the transgenic mice supports this conclusion. Taken together, these data suggest that for oligodendrocyte progenitors, ErbB2 signaling plays a role in governing a properly timed exit from the cell cycle during development into myelinating oligodendrocytes.
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Affiliation(s)
- Ju Young Kim
- Neurobiotechnology Center and Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio 43210, USA
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49
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Lu D, Mahmood A, Chopp M. Biologic Transplantation and Neurotrophin-Induced Neuroplasticity After Traumatic Brain Injury. J Head Trauma Rehabil 2003; 18:357-76. [PMID: 16222130 DOI: 10.1097/00001199-200307000-00006] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE In this review, we analyze progress in the treatment of traumatic brain injury with neurotrophins, growth factors and cell and tissue neurotransplantation. The primary objective of these therapies is to reduce neurologic deficits associated with the trauma by inducing neuroplasticity. These therapies are restorative and not necessarily neuroprotective. MAIN OUTCOME MEASURES An extensive literature on administration of neurotrophics factors and cell and tissue cerebral transplantation is reviewed. The effects of these therapeutic approaches on brain biochemical, molecular, cellular, and tissue responses are summarized. CONCLUSION The cumulative data indicate that cell therapy shows substantial promise in the treatment of neural injury.
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Affiliation(s)
- Dunyue Lu
- Department of Neurosurgery, Henry Ford Health System, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202, USA
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50
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Banks GB, Choy PT, Lavidis NA, Noakes PG. Neuromuscular synapses mediate motor axon branching and motoneuron survival during the embryonic period of programmed cell death. Dev Biol 2003; 257:71-84. [PMID: 12710958 DOI: 10.1016/s0012-1606(03)00056-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The embryonic period of motoneuron programmed cell death (PCD) is marked by transient motor axon branching, but the role of neuromuscular synapses in regulating motoneuron number and axonal branching is not known. Here, we test whether neuromuscular synapses are required for the quantitative association between reduced skeletal muscle contraction, increased motor neurite branching, and increased motoneuron survival. We achieved this by comparing agrin and rapsyn mutant mice that lack acetylcholine receptor (AChR) clusters. There were significant reductions in nerve-evoked skeletal muscle contraction, increases in intramuscular axonal branching, and increases in spinal motoneuron survival in agrin and rapsyn mutant mice compared with their wild-type littermates at embryonic day 18.5 (E18.5). The maximum nerve-evoked skeletal muscle contraction was reduced a further 17% in agrin mutants than in rapsyn mutants. This correlated to an increase in motor axon branch extension and number that was 38% more in agrin mutants than in rapsyn mutants. This suggests that specializations of the neuromuscular synapse that ensure efficient synaptic transmission and muscle contraction are also vital mediators of motor axon branching. However, these increases in motor axon branching did not correlate with increases in motoneuron survival when comparing agrin and rapsyn mutants. Thus, agrin-induced synaptic specializations are required for skeletal muscle to effectively control motoneuron numbers during embryonic development.
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Affiliation(s)
- Glen B Banks
- School of Biomedical Sciences, Department of Physiology and Pharmacology and SRC for Bio-informatics and Applied Genomics, University of Queensland, 4072, St. Lucia, Queensland, Australia
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