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Goffin L, Lemoine D, Clotman F. Potential contribution of spinal interneurons to the etiopathogenesis of amyotrophic lateral sclerosis. Front Neurosci 2024; 18:1434404. [PMID: 39091344 PMCID: PMC11293063 DOI: 10.3389/fnins.2024.1434404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 06/21/2024] [Indexed: 08/04/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) consists of a group of adult-onset fatal and incurable neurodegenerative disorders characterized by the progressive death of motor neurons (MNs) throughout the central nervous system (CNS). At first, ALS was considered to be an MN disease, caused by cell-autonomous mechanisms acting specifically in MNs. Accordingly, data from ALS patients and ALS animal models revealed alterations in excitability in multiple neuronal populations, including MNs, which were associated with a variety of cellular perturbations such as protein aggregation, ribonucleic acid (RNA) metabolism defects, calcium dyshomeostasis, modified electrophysiological properties, and autophagy malfunctions. However, experimental evidence rapidly demonstrated the involvement of other types of cells, including glial cells, in the etiopathogenesis of ALS through non-cell autonomous mechanisms. Surprisingly, the contribution of pre-motor interneurons (INs), which regulate MN activity and could therefore critically modulate their excitability at the onset or during the progression of the disease, has to date been severely underestimated. In this article, we review in detail how spinal pre-motor INs are affected in ALS and their possible involvement in the etiopathogenesis of the disease.
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Affiliation(s)
| | | | - Frédéric Clotman
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, Belgium
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2
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Hernández S, Salvany S, Casanovas A, Piedrafita L, Soto-Bernardini MC, Tarabal O, Blasco A, Gras S, Gatius A, Schwab MH, Calderó J, Esquerda JE. Persistent NRG1 Type III Overexpression in Spinal Motor Neurons Has No Therapeutic Effect on ALS-Related Pathology in SOD1 G93A Mice. Neurotherapeutics 2023; 20:1820-1834. [PMID: 37733208 PMCID: PMC10684470 DOI: 10.1007/s13311-023-01424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 09/22/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease affecting upper and lower motor neurons (MNs). Neuregulin-1 (NRG1) is a pleiotropic growth factor that has been shown to be potentially valuable for ALS when supplemented by means of viral-mediated gene therapy. However, these results are inconsistent with other reports. An alternative approach for investigating the therapeutic impact of NRG1 on ALS is the use of transgenic mouse lines with genetically defined NRG1 overexpression. Here, we took advantage of a mouse line with NRG1 type III overexpression in spinal cord α motor neurons (MN) to determine the impact of steadily enhanced NRG1 signalling on mutant superoxide dismutase 1 (SOD1)-induced disease. The phenotype of SOD1G93A-NRG1 double transgenic mice was analysed in detail, including neuropathology and extensive behavioural testing. At least 3 animals per condition and sex were histopathologically assessed, and a minimum of 10 mice per condition and sex were clinically evaluated. The accumulation of misfolded SOD1 (mfSOD1), MN degeneration, and a glia-mediated neuroinflammatory response are pathological hallmarks of ALS progression in SOD1G93A mice. None of these aspects was significantly improved when examined in double transgenic NRG1-SOD1G93A mice. In addition, behavioural testing revealed that NRG1 type III overexpression did not affect the survival of SOD1G93A mice but accelerated disease onset and worsened the motor phenotype.
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Affiliation(s)
- Sara Hernández
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Sara Salvany
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - M Clara Soto-Bernardini
- Department of Neurology, University Hospital Leipzig, Leipzig, Germany
- Center for Research in Biotechnology (CIB), Costa Rica Institute of Technology (TEC), Cartago, Costa Rica
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Alaó Gatius
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Markus H Schwab
- Paul Flechsig Institute of Neuropathology, University Hospital Leipzig, Leipzig, Germany
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain.
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Bak AN, Djukic S, Kadlecova M, Braunstein TH, Jensen DB, Meehan CF. Cytoplasmic TDP-43 accumulation drives changes in C-bouton number and size in a mouse model of sporadic Amyotrophic Lateral Sclerosis. Mol Cell Neurosci 2023; 125:103840. [PMID: 36921783 DOI: 10.1016/j.mcn.2023.103840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/11/2023] [Accepted: 03/04/2023] [Indexed: 03/14/2023] Open
Abstract
An altered neuronal excitability of spinal motoneurones has consistently been implicated in Amyotrophic Lateral Sclerosis (ALS) leading to several investigations of synaptic input to these motoneurones. One such input that has repeatedly been shown to be affected is a population of large cholinergic synapses terminating mainly on the soma of the motoneurones referred to as C-boutons. Most research on these synapses during disease progression has used transgenic Superoxide Dismutase 1 (SOD1) mouse models of the disease which have not only produced conflicting findings, but also fail to recapitulate the key pathological feature seen in ALS; cytoplasmic accumulations of TAR DNA-binding protein 43 (TDP-43). Additionally, they fail to distinguish between slow and fast motoneurones, the latter of which have more C-boutons, but are lost earlier in the disease. To circumvent these issues, we quantified the frequency and volume of C-boutons on traced soleus and gastrocnemius motoneurones, representing predominantly slow and fast motor pools respectively. Experiments were performed using the TDP-43ΔNLS mouse model that carries a transgenic construct of TDP-43 devoid of its nuclear localization signal, preventing its nuclear import. This results in the emergence of pathological TDP-43 inclusions in the cytoplasm, modelling the main pathology seen in this disorder, accompanied by a severe and lethal ALS phenotype. Our results confirmed changes in both the number and volume of C-boutons with a decrease in number on the more vulnerable, predominantly fast gastrocnemius motoneurones and an increase in number on the less vulnerable, predominantly slow soleus motoneurones. Importantly, these changes were only found in male mice. However, both sexes and motor pools showed a decrease in C-bouton volume. Our experiments confirm that cytoplasmic TDP-43 accumulation is sufficient to drive C-bouton changes.
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Affiliation(s)
| | - Svetlana Djukic
- Department of Neuroscience, University of Copenhagen, Denmark
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Gulino R. Synaptic Dysfunction and Plasticity in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:ijms24054613. [PMID: 36902042 PMCID: PMC10003601 DOI: 10.3390/ijms24054613] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Recent evidence has supported the hypothesis that amyotrophic lateral sclerosis (ALS) is a multi-step disease, as the onset of symptoms occurs after sequential exposure to a defined number of risk factors. Despite the lack of precise identification of these disease determinants, it is known that genetic mutations may contribute to one or more of the steps leading to ALS onset, the remaining being linked to environmental factors and lifestyle. It also appears evident that compensatory plastic changes taking place at all levels of the nervous system during ALS etiopathogenesis may likely counteract the functional effects of neurodegeneration and affect the timing of disease onset and progression. Functional and structural events of synaptic plasticity probably represent the main mechanisms underlying this adaptive capability, causing a significant, although partial and transient, resiliency of the nervous system affected by a neurodegenerative disease. On the other hand, the failure of synaptic functions and plasticity may be part of the pathological process. The aim of this review was to summarize what it is known today about the controversial involvement of synapses in ALS etiopathogenesis, and an analysis of the literature, although not exhaustive, confirmed that synaptic dysfunction is an early pathogenetic process in ALS. Moreover, it appears that adequate modulation of structural and functional synaptic plasticity may likely support function sparing and delay disease progression.
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Affiliation(s)
- Rosario Gulino
- Department of Biomedical and Biotechnological Sciences, Physiology Section, University of Catania, 95123 Catania, Italy
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5
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Cavarsan CF, Steele PR, Genry LT, Reedich EJ, McCane LM, LaPre KJ, Puritz AC, Manuel M, Katenka N, Quinlan KA. Inhibitory interneurons show early dysfunction in a SOD1 mouse model of amyotrophic lateral sclerosis. J Physiol 2023; 601:647-667. [PMID: 36515374 PMCID: PMC9898203 DOI: 10.1113/jp284192] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
Few studies in amyotrophic lateral sclerosis (ALS) measure effects of the disease on inhibitory interneurons synapsing onto motoneurons (MNs). However, inhibitory interneurons could contribute to dysfunction, particularly if altered before MN neuropathology, and establish a long-term imbalance of inhibition/excitation. We directly assessed excitability and morphology of glycinergic (GlyT2 expressing) ventral lumbar interneurons from SOD1G93AGlyT2eGFP (SOD1) and wild-type GlyT2eGFP (WT) mice on postnatal days 6-10. Patch clamp revealed dampened excitability in SOD1 interneurons, including depolarized persistent inward currents (PICs), increased voltage and current threshold for firing action potentials, along with a marginal decrease in afterhyperpolarization duration. Primary neurites of ventral SOD1 inhibitory interneurons were larger in volume and surface area than WT. GlyT2 interneurons were then divided into three subgroups based on location: (1) interneurons within 100 μm of the ventral white matter, where Renshaw cells (RCs) are located, (2) interneurons interspersed with MNs in lamina IX, and (3) interneurons in the intermediate ventral area including laminae VII and VIII. Ventral interneurons in the RC area were the most profoundly affected, exhibiting more depolarized PICs and larger primary neurites. Interneurons in lamina IX had depolarized PIC onset. In lamina VII-VIII, interneurons were least affected. In summary, inhibitory interneurons show very early region-specific perturbations poised to impact excitatory/inhibitory balance of MNs, modify motor output and provide early biomarkers of ALS. Therapeutics like riluzole that universally reduce CNS excitability could exacerbate the inhibitory dysfunction described here. KEY POINTS: Spinal inhibitory interneurons could contribute to amyotrophic lateral sclerosis (ALS) pathology, but their excitability has never been directly measured. We studied the excitability and morphology of glycinergic interneurons in early postnatal transgenic mice (SOD1G93A GlyT2eGFP). Interneurons were less excitable and had marginally smaller somas but larger primary neurites in SOD1 mice. GlyT2 interneurons were analysed according to their localization within the ventral spinal cord. Interestingly, the greatest differences were observed in the most ventrally located interneurons. We conclude that inhibitory interneurons show presymptomatic changes that may contribute to excitatory/inhibitory imbalance in ALS.
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Affiliation(s)
- Clarissa F Cavarsan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Preston R Steele
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - Landon T Genry
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - Emily J Reedich
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Lynn M McCane
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - Kay J LaPre
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Alyssa C Puritz
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Marin Manuel
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Natallia Katenka
- Department of Computer Science and Statistics, University of Rhode Island, Kingston, RI, USA
| | - Katharina A Quinlan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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6
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Salvany S, Casanovas A, Piedrafita L, Gras S, Calderó J, Esquerda JE. Accumulation of misfolded SOD1 outlines distinct patterns of motor neuron pathology and death during disease progression in a SOD1 G93A mouse model of amyotrophic lateral sclerosis. Brain Pathol 2022; 32:e13078. [PMID: 35584812 PMCID: PMC9616096 DOI: 10.1111/bpa.13078] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/11/2022] [Indexed: 12/12/2022] Open
Abstract
Early misfolded superoxide dismutase 1 (mfSOD1) accumulation, motor neuron (MN) degeneration, and microgliosis are hallmark pathological features in SOD1G93A amyotrophic lateral sclerosis (ALS) mice. Because of the different vulnerabilities of distinct MN subtypes, degenerating and surviving MNs coexist in different proportions during disease progression. By examining the expression of misfolded conformers of SOD1 using specific antibodies, we defined distinct MN phenotypes that were evaluated during disease progression and the local neuroinflammatory reaction. The most severe phenotype corresponded to somata of fast‐twitch subtype MNs, which exhibited highly positive mfSOD1 immunostaining and an extreme degree of vacuolar degeneration. Vacuoles, which are of mitochondrial origin, contain mfSOD1 in conjunction with nonmitochondrial proteins, such as chromogranin, CD81, and flotillin. The fusion of ER‐derived vesicles enriched in mfSOD1 with outer mitochondrial membranes is thought to be the primary mechanism for vacuole formation. In addition, the ulterior coalescence of enlarged mitochondria may lead to the formation of giant vacuoles. Vacuolar degeneration is a transient degenerative process occurring early during the presymptomatic stages of the disease in ALS mice. Some vacuolated MNs are also positive for pMLKL, the effector protein of necroptosis. This indicates a newly described mechanism in which extracellular vesicles derived from damaged MNs, via cellular secretion or necroptotic disruption, may be the triggers for initiating neuroinflammation, glial‐mediated neurotoxicity, and disease spreading. Furthermore, as MN degeneration in mutant SOD1 mice is noncell autonomous, the effects of experimentally increasing or decreasing the microglial response on the expression of MN phenotypes were also evaluated, demonstrating bidirectional cross talk signaling between the degree of expression of mfSOD1 and local neuroinflammation. More detailed knowledge regarding these processes occurring long before the end stages of the disease is necessary to identify novel molecular targets for future preclinical testing.
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Affiliation(s)
- Sara Salvany
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Sílvia Gras
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Jordi Calderó
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Patologia Neuromuscular Experimental, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
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7
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Gras S, Blasco A, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Rueda R, Pereira SL, Navarro X, Esquerda JE, Calderó J. Beneficial effects of dietary supplementation with green tea catechins and cocoa flavanols on aging-related regressive changes in the mouse neuromuscular system. Aging (Albany NY) 2021; 13:18051-18093. [PMID: 34319911 PMCID: PMC8351677 DOI: 10.18632/aging.203336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/19/2021] [Indexed: 12/17/2022]
Abstract
Besides skeletal muscle wasting, sarcopenia entails morphological and molecular changes in distinct components of the neuromuscular system, including spinal cord motoneurons (MNs) and neuromuscular junctions (NMJs); moreover, noticeable microgliosis has also been observed around aged MNs. Here we examined the impact of two flavonoid-enriched diets containing either green tea extract (GTE) catechins or cocoa flavanols on age-associated regressive changes in the neuromuscular system of C57BL/6J mice. Compared to control mice, GTE- and cocoa-supplementation significantly improved the survival rate of mice, reduced the proportion of fibers with lipofuscin aggregates and central nuclei, and increased the density of satellite cells in skeletal muscles. Additionally, both supplements significantly augmented the number of innervated NMJs and their degree of maturity compared to controls. GTE, but not cocoa, prominently increased the density of VAChT and VGluT2 afferent synapses on MNs, which were lost in control aged spinal cords; conversely, cocoa, but not GTE, significantly augmented the proportion of VGluT1 afferent synapses on aged MNs. Moreover, GTE, but not cocoa, reduced aging-associated microgliosis and increased the proportion of neuroprotective microglial phenotypes. Our data indicate that certain plant flavonoids may be beneficial in the nutritional management of age-related deterioration of the neuromuscular system.
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Affiliation(s)
- Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alejandro Barranco
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - Tapas Das
- Abbott Nutrition, Research and Development, Columbus, OH 43215, USA
| | - Ricardo Rueda
- Abbott Nutrition, Research and Development, Granada, Spain
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Josep E. Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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Shadrach JL, Gomez-Frittelli J, Kaltschmidt JA. Proprioception revisited: where do we stand? CURRENT OPINION IN PHYSIOLOGY 2021; 21:23-28. [PMID: 34222735 DOI: 10.1016/j.cophys.2021.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Originally referred to as 'muscle sense', the notion that skeletal muscle held a peripheral sensory function was first described early in the 19th century. Foundational experiments by Sherrington in the early 20th century definitively demonstrated that proprioceptors contained within skeletal muscle, tendons, and joints are innervated by sensory neurons and play an important role in the control of movement. In this review, we will highlight several recent advances in the ongoing effort to further define the molecular diversity underlying the proprioceptive sensorimotor system. Together, the work summarized here represents our current understanding of sensorimotor circuit formation during development and the mechanisms that regulate the integration of proprioceptive feedback into the spinal circuits that control locomotion in both normal and diseased states.
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Affiliation(s)
- Jennifer L Shadrach
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
| | - Julieta Gomez-Frittelli
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA.,Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Julia A Kaltschmidt
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
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Mille T, Quilgars C, Cazalets J, Bertrand SS. Acetylcholine and spinal locomotor networks: The insider. Physiol Rep 2021; 9:e14736. [PMID: 33527727 PMCID: PMC7851432 DOI: 10.14814/phy2.14736] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 01/07/2023] Open
Abstract
This article aims to review studies that have investigated the role of neurons that use the transmitter acetylcholine (ACh) in controlling the operation of locomotor neural networks within the spinal cord. This cholinergic system has the particularity of being completely intraspinal. We describe the different effects exerted by spinal cholinergic neurons on locomotor circuitry by the pharmacological activation or blockade of this propriospinal system, as well as describing its different cellular and subcellular targets. Through the activation of one ionotropic receptor, the nicotinic receptor, and five metabotropic receptors, the M1 to M5 muscarinic receptors, the cholinergic system exerts a powerful control both on synaptic transmission and locomotor network neuron excitability. Although tremendous advances have been made in our understanding of the spinal cholinergic system's involvement in the physiology and pathophysiology of locomotor networks, gaps still remain, including the precise role of the different subtypes of cholinergic neurons as well as their pre- and postsynaptic partners. Improving our knowledge of the propriospinal cholinergic system is of major relevance to finding new cellular targets and therapeutics in countering the debilitating effects of neurodegenerative diseases and restoring motor functions after spinal cord injury.
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Affiliation(s)
- Théo Mille
- Université de BordeauxCNRS UMR 5287INCIABordeauxFrance
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10
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Konsolaki E, Koropouli E, Tsape E, Pothakos K, Zagoraiou L. Genetic Inactivation of Cholinergic C Bouton Output Improves Motor Performance but not Survival in a Mouse Model of Amyotrophic Lateral Sclerosis. Neuroscience 2020; 450:71-80. [DOI: 10.1016/j.neuroscience.2020.07.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/06/2020] [Accepted: 07/26/2020] [Indexed: 12/17/2022]
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11
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Blasco A, Gras S, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Pereira SL, Navarro X, Rueda R, Esquerda JE, Calderó J. Motoneuron deafferentation and gliosis occur in association with neuromuscular regressive changes during ageing in mice. J Cachexia Sarcopenia Muscle 2020; 11:1628-1660. [PMID: 32691534 PMCID: PMC7749545 DOI: 10.1002/jcsm.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying the age-associated loss of muscle mass and function (sarcopenia) are poorly understood, hampering the development of effective treatment strategies. Here, we performed a detailed characterization of age-related pathophysiological changes in the mouse neuromuscular system. METHODS Young, adult, middle-aged, and old (1, 4, 14, and 24-30 months old, respectively) C57BL/6J mice were used. Motor behavioural and electrophysiological tests and histological and immunocytochemical procedures were carried out to simultaneously analyse structural, molecular, and functional age-related changes in distinct cellular components of the neuromuscular system. RESULTS Ageing was not accompanied by a significant loss of spinal motoneurons (MNs), although a proportion (~15%) of them in old mice exhibited an abnormally dark appearance. Dark MNs were also observed in adult (~9%) and young (~4%) animals, suggesting that during ageing, some MNs undergo early deleterious changes, which may not lead to MN death. Old MNs were depleted of cholinergic and glutamatergic inputs (~40% and ~45%, respectively, P < 0.01), suggestive of age-associated alterations in MN excitability. Prominent microgliosis and astrogliosis [~93% (P < 0.001) and ~100% (P < 0.0001) increase vs. adults, respectively] were found in old spinal cords, with increased density of pro-inflammatory M1 microglia and A1 astroglia (25-fold and 4-fold increase, respectively, P < 0.0001). Ageing resulted in significant reductions in the nerve conduction velocity and the compound muscle action potential amplitude (~30%, P < 0.05, vs. adults) in old distal plantar muscles. Compared with adult muscles, old muscles exhibited significantly higher numbers of both denervated and polyinnervated neuromuscular junctions, changes in fibre type composition, higher proportion of fibres showing central nuclei and lipofuscin aggregates, depletion of satellite cells, and augmented expression of different molecules related to development, plasticity, and maintenance of neuromuscular junctions, including calcitonin gene-related peptide, growth associated protein 43, agrin, fibroblast growth factor binding protein 1, and transforming growth factor-β1. Overall, these alterations occurred at varying degrees in all the muscles analysed, with no correlation between the age-related changes observed and myofiber type composition or muscle topography. CONCLUSIONS Our data provide a global view of age-associated neuromuscular changes in a mouse model of ageing and help to advance understanding of contributing pathways leading to development of sarcopenia.
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Affiliation(s)
- Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | | | - Tapas Das
- Abbott Nutrition Research and Development, Columbus, OH, USA
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Ricardo Rueda
- Abbott Nutrition Research and Development, Granada, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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12
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Crabé R, Aimond F, Gosset P, Scamps F, Raoul C. How Degeneration of Cells Surrounding Motoneurons Contributes to Amyotrophic Lateral Sclerosis. Cells 2020; 9:cells9122550. [PMID: 33260927 PMCID: PMC7760029 DOI: 10.3390/cells9122550] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by the progressive degeneration of upper and lower motoneurons. Despite motoneuron death being recognized as the cardinal event of the disease, the loss of glial cells and interneurons in the brain and spinal cord accompanies and even precedes motoneuron elimination. In this review, we provide striking evidence that the degeneration of astrocytes and oligodendrocytes, in addition to inhibitory and modulatory interneurons, disrupt the functionally coherent environment of motoneurons. We discuss the extent to which the degeneration of glial cells and interneurons also contributes to the decline of the motor system. This pathogenic cellular network therefore represents a novel strategic field of therapeutic investigation.
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Affiliation(s)
- Roxane Crabé
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Franck Aimond
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Philippe Gosset
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Frédérique Scamps
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Cédric Raoul
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
- Laboratory of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence:
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13
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Jørgensen HS, Jensen DB, Dimintiyanova KP, Bonnevie VS, Hedegaard A, Lehnhoff J, Moldovan M, Grondahl L, Meehan CF. Increased Axon Initial Segment Length Results in Increased Na + Currents in Spinal Motoneurones at Symptom Onset in the G127X SOD1 Mouse Model of Amyotrophic Lateral Sclerosis. Neuroscience 2020; 468:247-264. [PMID: 33246068 DOI: 10.1016/j.neuroscience.2020.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 10/22/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease preferentially affecting motoneurones. Transgenic mouse models have been used to investigate the role of abnormal motoneurone excitability in this disease. Whilst an increased excitability has repeatedly been demonstrated in vitro in neonatal and embryonic preparations from SOD1 mouse models, the results from the only studies to record in vivo from spinal motoneurones in adult SOD1 models have produced conflicting findings. Deficits in repetitive firing have been reported in G93A SOD1(high copy number) mice but not in presymptomatic G127X SOD1 mice despite shorter motoneurone axon initial segments (AISs) in these mice. These discrepancies may be due to the earlier disease onset and prolonged disease progression in G93A SOD1 mice with recordings potentially performed at a later sub-clinical stage of the disease in this mouse. To test this, and to explore how the evolution of excitability changes with symptom onset we performed in vivo intracellular recording and AIS labelling in G127X SOD1 mice immediately after symptom onset. No reductions in repetitive firing were observed showing that this is not a common feature across all ALS models. Immunohistochemistry for the Na+ channel Nav1.6 showed that motoneurone AISs increase in length in G127X SOD1 mice at symptom onset. Consistent with this, the rate of rise of AIS components of antidromic action potentials were significantly faster confirming that this increase in length represents an increase in AIS Na+ channels occurring at symptom onset in this model.
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Affiliation(s)
- H S Jørgensen
- Department of Neuroscience, University of Copenhagen, Denmark
| | - D B Jensen
- Department of Neuroscience, University of Copenhagen, Denmark
| | | | - V S Bonnevie
- Department of Neuroscience, University of Copenhagen, Denmark
| | - A Hedegaard
- Department of Neuroscience, University of Copenhagen, Denmark
| | - J Lehnhoff
- Department of Neuroscience, University of Copenhagen, Denmark
| | - M Moldovan
- Department of Neuroscience, University of Copenhagen, Denmark
| | - L Grondahl
- Department of Neuroscience, University of Copenhagen, Denmark
| | - C F Meehan
- Department of Neuroscience, University of Copenhagen, Denmark.
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14
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Jensen DB, Kadlecova M, Allodi I, Meehan CF. Spinal motoneurones are intrinsically more responsive in the adult G93A SOD1 mouse model of amyotrophic lateral sclerosis. J Physiol 2020; 598:4385-4403. [PMID: 32716521 DOI: 10.1113/jp280097] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/17/2020] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Although in vitro recordings using neonatal preparations from mouse models of amyotrophic lateral sclerosis (ALS) suggest increased motoneurone excitability, in vivo recordings in adult ALS mouse models have been conflicting. In adult G93A SOD1 models, spinal motoneurones have previously been shown to have deficits in repetitive firing, in contrast to the G127X SOD1 mouse model. Our in vivo intracellular recordings in barbiturate-anaesthetized adult male G93A SOD1 mice reveal that the incidence of failure to fire with current injection was equally low in control and ALS mice (∼2%). We show that failure to fire repetitively can be a consequence of experimental protocol and should not be used alone to classify otherwise normal motoneurones as hypo-excitable. Motoneurones in the G93A SOD1 mice showed an increased response to inputs, with lower rheobase, higher input-output gains and increased activation of persistent inward currents. ABSTRACT In vitro studies from transgenic amyotrophic lateral sclerosis models have suggested an increased excitability of spinal motoneurones. However, in vivo intracellular recordings from adult amyotrophic lateral sclerosis mice models have produced conflicting findings. Previous investigations using barbiturate anaesthetized G93A SOD1 mice have suggested that some motoneurones are hypo-excitable, defined by deficits in repetitive firing. Our own previous recordings in G127X SOD1 mice using different anaesthesia, however, showed no repetitive firing deficits and increased persistent inward currents at symptom onset. These discrepancies may be a result of differences between models, symptomatic stage, anaesthesia or technical differences. To investigate this, we repeated our original experiments, but in adult male G93A SOD1 mice, at both presymptomatic and symptomatic stages, under barbiturate anaesthesia. In vivo intracellular recordings from antidromically identified spinal motoneurones revealed that the incidence of failure to fire with current injection was equally low in control and G93A SOD1 mice (∼2%). Motoneurones in G93A SOD1 mice fired significantly more spontaneous action potentials. Rheobase was significantly lower and the input resistance and input-output gain were significantly higher in both presymptomatic and symptomatic G93A SOD1 mice. This was despite a significant increase in the duration of the post-spike after-hyperpolarization in both presymptomatic and symptomatic G93A SOD1 mice. Finally, evidence of increased activation of persistent inward currents was seen in both presymptomatic and symptomatic G93A SOD1 mice. Our results do not confirm previous reports of hypo-excitability of spinal motoneurones in the G93A SOD1 mouse and demonstrate that the motoneurones show an increased response to inputs.
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Affiliation(s)
- Dennis B Jensen
- Department of Neuroscience, University of Copenhagen, Panum Institute, Blegdamsvej 3, Copenhagen N, Denmark
| | - Marion Kadlecova
- Department of Neuroscience, University of Copenhagen, Panum Institute, Blegdamsvej 3, Copenhagen N, Denmark
| | - Ilary Allodi
- Department of Neuroscience, University of Copenhagen, Panum Institute, Blegdamsvej 3, Copenhagen N, Denmark
| | - Claire F Meehan
- Department of Neuroscience, University of Copenhagen, Panum Institute, Blegdamsvej 3, Copenhagen N, Denmark
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15
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Differential Loss of Spinal Interneurons in a Mouse Model of ALS. Neuroscience 2020; 450:81-95. [PMID: 32858144 DOI: 10.1016/j.neuroscience.2020.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 08/04/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) leads to a loss of specific motor neuron populations in the spinal cord and cortex. Emerging evidence suggests that interneurons may also be affected, but a detailed characterization of interneuron loss and its potential impacts on motor neuron loss and disease progression is lacking. To examine this issue, the fate of V1 inhibitory neurons during ALS was assessed in the ventral spinal cord using the SODG93A mouse model. The V1 population makes up ∼30% of all ventral inhibitory neurons, ∼50% of direct inhibitory synaptic contacts onto motor neuron cell bodies, and is thought to play a key role in modulating motor output, in part through recurrent and reciprocal inhibitory circuits. We find that approximately half of V1 inhibitory neurons are lost in SODG93A mice at late disease stages, but that this loss is delayed relative to the loss of motor neurons and V2a excitatory neurons. We further identify V1 subpopulations based on transcription factor expression that are differentially susceptible to degeneration in SODG93A mice. At an early disease stage, we show that V1 synaptic contacts with motor neuron cell bodies increase, suggesting an upregulation of inhibition before V1 neurons are lost in substantial numbers. These data support a model in which progressive changes in V1 synaptic contacts early in disease, and in select V1 subpopulations at later stages, represent a compensatory upregulation and then deleterious breakdown of specific interneuron circuits within the spinal cord.
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16
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Gunes ZI, Kan VWY, Ye X, Liebscher S. Exciting Complexity: The Role of Motor Circuit Elements in ALS Pathophysiology. Front Neurosci 2020; 14:573. [PMID: 32625051 PMCID: PMC7311855 DOI: 10.3389/fnins.2020.00573] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the degeneration of both upper and lower motor neurons. Despite decades of research, we still to date lack a cure or disease modifying treatment, emphasizing the need for a much-improved insight into disease mechanisms and cell type vulnerability. Altered neuronal excitability is a common phenomenon reported in ALS patients, as well as in animal models of the disease, but the cellular and circuit processes involved, as well as the causal relevance of those observations to molecular alterations and final cell death, remain poorly understood. Here, we review evidence from clinical studies, cell type-specific electrophysiology, genetic manipulations and molecular characterizations in animal models and culture experiments, which argue for a causal involvement of complex alterations of structure, function and connectivity of different neuronal subtypes within the cortical and spinal cord motor circuitries. We also summarize the current knowledge regarding the detrimental role of astrocytes and reassess the frequently proposed hypothesis of glutamate-mediated excitotoxicity with respect to changes in neuronal excitability. Together, these findings suggest multifaceted cell type-, brain area- and disease stage- specific disturbances of the excitation/inhibition balance as a cardinal aspect of ALS pathophysiology.
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Affiliation(s)
- Zeynep I Gunes
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Munich, Germany.,Graduate School of Systemic Neurosciences, Ludwig Maximilians University Munich, Munich, Germany.,Biomedical Center, Ludwig Maximilians University Munich, Munich, Germany
| | - Vanessa W Y Kan
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Munich, Germany.,Graduate School of Systemic Neurosciences, Ludwig Maximilians University Munich, Munich, Germany.,Biomedical Center, Ludwig Maximilians University Munich, Munich, Germany
| | - XiaoQian Ye
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Munich, Germany.,Biomedical Center, Ludwig Maximilians University Munich, Munich, Germany
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Munich, Germany.,Biomedical Center, Ludwig Maximilians University Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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17
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Andrés-Benito P, Povedano M, Torres P, Portero-Otín M, Ferrer I. Altered Dynein Axonemal Assembly Factor 1 Expression in C-Boutons in Bulbar and Spinal Cord Motor-Neurons in Sporadic Amyotrophic Lateral Sclerosis. J Neuropathol Exp Neurol 2020; 78:416-425. [PMID: 30939186 DOI: 10.1093/jnen/nlz019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Dyneins are major components of microtubules. Dynein assembly is modulated by a heterogeneous group of dynein axonemal assembly factors (DNAAFs). The present study analyzes dynein axonemal assembly factor 1 (DNAAF1) and leucine-rich repeat-containing protein 50 (LRRC50), the corresponding encoded protein, in lower motor neurons in spinal cord of sALS postmortem samples and hSOD1-G93A transgenic mice compared with controls. DNAAF1 mRNA is significantly reduced in the anterior horn in sALS, and LRRC50 immunoreactivity is significantly reduced in C-boutons of the remaining motor neurons of the anterior horn, dorsal nucleus of the vagus nerve, and hypoglossal nuclei at terminal stages of ALS. LRRC50 immunoreactivity has a perinuclear distribution in motor neurons in sALS thus suggesting a disorder of transport. The number of LRRC50-/S1R-immunoreactive structures is also significantly decreased in hSOD1-G93A transgenic mice at the age of 90 days (preclinical stages), and the number of motor neurons with LRRC50-immunoreactive structures is significantly reduced in animals aged 150 days (clinical stages). These observations suggest cholinergic denervation of motor neurons as a pathogenic factor in motor neuron disease. LRRC50 protein levels were not detected in human CSF.
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Affiliation(s)
- Pol Andrés-Benito
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Spain.,Institute Carlos III, Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Hospitalet de Llobregat, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
| | - Mònica Povedano
- Functional Unit of Amyotrophic Lateral Sclerosis (UFELA), Service of Neurology, Bellvitge University Hospital, Hospitalet de Llobregat, Spain
| | - Pascual Torres
- Departament Medicina Experimental, Facultat de Medicina, Universitat de Lleida, IRBLLEIDA, Lleida, Spain
| | - Manuel Portero-Otín
- Departament Medicina Experimental, Facultat de Medicina, Universitat de Lleida, IRBLLEIDA, Lleida, Spain
| | - Isidro Ferrer
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Spain.,Institute Carlos III, Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Hospitalet de Llobregat, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain.,Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, L'Hospitalet de Llobregat, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
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18
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Gatius A, Tarabal O, Cayuela P, Casanovas A, Piedrafita L, Salvany S, Hernández S, Soler RM, Esquerda JE, Calderó J. The Y172 Monoclonal Antibody Against p-c-Jun (Ser63) Is a Marker of the Postsynaptic Compartment of C-Type Cholinergic Afferent Synapses on Motoneurons. Front Cell Neurosci 2020; 13:582. [PMID: 32038174 PMCID: PMC6992659 DOI: 10.3389/fncel.2019.00582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/20/2019] [Indexed: 12/02/2022] Open
Abstract
C-bouton-type cholinergic afferents exert an important function in controlling motoneuron (MN) excitability. During the immunocytochemical analysis of the role of c-Jun in MNs with a monoclonal (clone Y172) antibody against phospho (p)-c-Jun (serine [Ser]63), unexpected labeling was identified in the cell body cytoplasm. As predicted for c-Jun in adult spinal cord, very few, if any MNs exhibited nuclear immunoreactivity with the Y172 antibody; conversely, virtually all MNs displayed strong Y172 immunostaining in cytoplasmic structures scattered throughout the soma and proximal dendrites. The majority of these cytoplasmic Y172-positive profiles was closely associated with VAChT-positive C-boutons, but not with other types of nerve afferents contacting MNs. Ultrastructural analysis revealed that cytoplasmic Y172 immunostaining was selectively located at the subsurface cistern (SSC) of C-boutons and also in the inner areas of the endoplasmic reticulum (ER). We also described changes in cytoplasmic Y172 immunoreactivity in injured and degenerating MNs. Moreover, we noticed that MNs from NRG1 type III-overexpressing transgenic mice, which show abnormally expanded SSCs, exhibited an increase in the density and size of peripherally located Y172-positive profiles. A similar immunocytochemical pattern to that of the Y172 antibody in MNs was found with a polyclonal antibody against p-c-Jun (Ser63) but not with another polyclonal antibody that recognizes c-Jun phosphorylated at a different site. No differential band patterns were found by western blotting with any of the antibodies against c-Jun or p-c-Jun used in our study. In cultured MNs, Y172-positive oval profiles were distributed in the cell body and proximal dendrites. The in vitro lentiviral-based knockdown of c-Jun resulted in a dramatic decrease in nuclear Y172 immunostaining in MNs without any reduction in the density of cytoplasmic Y172-positive profiles, suggesting that the synaptic antigen recognized by the antibody corresponds to a C-bouton-specific protein other than p-c-Jun. Our results lay the foundation for further studies aimed at identifying this protein and determining its role in this particular type of synapse.
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Affiliation(s)
- Alaó Gatius
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Paula Cayuela
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sara Salvany
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sara Hernández
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Rosa M Soler
- Unitat de Senyalització Neuronal, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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19
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Cholinergic modulation of motor neurons through the C-boutons are necessary for the locomotor compensation for severe motor neuron loss during amyotrophic lateral sclerosis disease progression. Behav Brain Res 2019; 369:111914. [DOI: 10.1016/j.bbr.2019.111914] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/02/2019] [Accepted: 04/13/2019] [Indexed: 12/11/2022]
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20
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Ragagnin AMG, Shadfar S, Vidal M, Jamali MS, Atkin JD. Motor Neuron Susceptibility in ALS/FTD. Front Neurosci 2019; 13:532. [PMID: 31316328 PMCID: PMC6610326 DOI: 10.3389/fnins.2019.00532] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/08/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the death of both upper and lower motor neurons (MNs) in the brain, brainstem and spinal cord. The neurodegenerative mechanisms leading to MN loss in ALS are not fully understood. Importantly, the reasons why MNs are specifically targeted in this disorder are unclear, when the proteins associated genetically or pathologically with ALS are expressed ubiquitously. Furthermore, MNs themselves are not affected equally; specific MNs subpopulations are more susceptible than others in both animal models and human patients. Corticospinal MNs and lower somatic MNs, which innervate voluntary muscles, degenerate more readily than specific subgroups of lower MNs, which remain resistant to degeneration, reflecting the clinical manifestations of ALS. In this review, we discuss the possible factors intrinsic to MNs that render them uniquely susceptible to neurodegeneration in ALS. We also speculate why some MN subpopulations are more vulnerable than others, focusing on both their molecular and physiological properties. Finally, we review the anatomical network and neuronal microenvironment as determinants of MN subtype vulnerability and hence the progression of ALS.
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Affiliation(s)
- Audrey M G Ragagnin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sina Shadfar
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Marta Vidal
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Md Shafi Jamali
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julie D Atkin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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21
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Gulino R, Vicario N, Giunta MAS, Spoto G, Calabrese G, Vecchio M, Gulisano M, Leanza G, Parenti R. Neuromuscular Plasticity in a Mouse Neurotoxic Model of Spinal Motoneuronal Loss. Int J Mol Sci 2019; 20:ijms20061500. [PMID: 30917493 PMCID: PMC6471664 DOI: 10.3390/ijms20061500] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/19/2019] [Accepted: 03/24/2019] [Indexed: 12/11/2022] Open
Abstract
Despite the relevant research efforts, the causes of amyotrophic lateral sclerosis (ALS) are still unknown and no effective cure is available. Many authors suggest that ALS is a multi-system disease caused by a network failure instead of a cell-autonomous pathology restricted to motoneurons. Although motoneuronal loss is the critical hallmark of ALS given their specific vulnerability, other cell populations, including muscle and glial cells, are involved in disease onset and progression, but unraveling their specific role and crosstalk requires further investigation. In particular, little is known about the plastic changes of the degenerating motor system. These spontaneous compensatory processes are unable to halt the disease progression, but their elucidation and possible use as a therapeutic target represents an important aim of ALS research. Genetic animal models of disease represent useful tools to validate proven hypotheses or to test potential therapies, and the conception of novel hypotheses about ALS causes or the study of pathogenic mechanisms may be advantaged by the use of relatively simple in vivo models recapitulating specific aspects of the disease, thus avoiding the inclusion of too many confounding factors in an experimental setting. Here, we used a neurotoxic model of spinal motoneuron depletion induced by injection of cholera toxin-B saporin in the gastrocnemius muscle to investigate the possible occurrence of compensatory changes in both the muscle and spinal cord. The results showed that, following the lesion, the skeletal muscle became atrophic and displayed electromyographic activity similar to that observed in ALS patients. Moreover, the changes in muscle fiber morphology were different from that observed in ALS models, thus suggesting that some muscular effects of disease may be primary effects instead of being simply caused by denervation. Notably, we found plastic changes in the surviving motoneurons that can produce a functional restoration probably similar to the compensatory changes occurring in disease. These changes could be at least partially driven by glutamatergic signaling, and astrocytes contacting the surviving motoneurons may support this process.
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Affiliation(s)
- Rosario Gulino
- Laboratory of Neurophysiology, Department of Biomedical and Biotechnological Science, Section of Physiology, University of Catania, Catania 95123, Italy.
| | - Nunzio Vicario
- Laboratory of Cellular and Molecular Physiology, Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania 95123, Italy.
| | - Maria A S Giunta
- Laboratory of Cellular and Molecular Physiology, Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania 95123, Italy.
| | - Graziana Spoto
- Laboratory of Cellular and Molecular Physiology, Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania 95123, Italy.
| | - Giovanna Calabrese
- Laboratory of Cellular and Molecular Physiology, Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania 95123, Italy.
| | - Michele Vecchio
- Rehabilitation Unit, "AOU Policlinico Vittorio Emanuele" and Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania 95123, Italy.
| | - Massimo Gulisano
- Laboratory of Synthetic and Systems Biology, Department of Drug Sciences, University of Catania, Catania 95125, Italy.
| | - Giampiero Leanza
- Laboratory of Neurogenesis and Repair, Department of Drug Sciences, University of Catania, Catania 95125, Italy.
| | - Rosalba Parenti
- Laboratory of Cellular and Molecular Physiology, Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania 95123, Italy.
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22
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Salvany S, Casanovas A, Tarabal O, Piedrafita L, Hernández S, Santafé M, Soto-Bernardini MC, Calderó J, Schwab MH, Esquerda JE. Localization and dynamic changes of neuregulin-1 at C-type synaptic boutons in association with motor neuron injury and repair. FASEB J 2019; 33:7833-7851. [PMID: 30912977 DOI: 10.1096/fj.201802329r] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
C-type synaptic boutons (C-boutons) provide cholinergic afferent input to spinal cord motor neurons (MNs), which display an endoplasmic reticulum (ER)-related subsurface cistern (SSC) adjacent to their postsynaptic membrane. A constellation of postsynaptic proteins is clustered at C-boutons, including M2 muscarinic receptors, potassium channels, and σ-1 receptors. In addition, we previously found that neuregulin (NRG)1 is associated with C-boutons at postsynaptic SSCs, whereas its ErbB receptors are located in the presynaptic compartment. C-bouton-mediated regulation of MN excitability has been implicated in MN disease, but NRG1-mediated functions and the impact of various pathologic conditions on C-bouton integrity have not been studied in detail. Here, we investigated changes in C-boutons after electrical stimulation, pharmacological treatment, and peripheral nerve axotomy. SSC-linked NRG1 clusters were severely disrupted in acutely stressed MNs and after tunicamycin-induced ER stress. In axotomized MNs, C-bouton loss occurred in concomitance with microglial recruitment and was prevented by the ER stress inhibitor salubrinal. Activated microglia displayed a positive chemotaxis to C-boutons. Analysis of transgenic mice overexpressing NRG1 type I and type III isoforms in MNs indicated that NRG1 type III acts as an organizer of SSC-like structures, whereas NRG1 type I promotes synaptogenesis of presynaptic cholinergic terminals. Moreover, MN-derived NRG1 signals may regulate the activity of perineuronal microglial cells. Together, these data provide new insights into the molecular and cellular pathology of C-boutons in MN injury and suggest that distinct NRG1 isoform-mediated signaling functions regulate the complex matching between pre- and postsynaptic C-bouton elements.-Salvany, S., Casanovas, A., Tarabal, O., Piedrafita, L., Hernández, S., Santafé, M., Soto-Bernardini, M. C., Calderó, J., Schwab, M. H., Esquerda, J. E. Localization and dynamic changes of neuregulin-1 at C-type synaptic boutons in association with motor neuron injury and repair.
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Affiliation(s)
- Sara Salvany
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Sara Hernández
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Manuel Santafé
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Catalonia, Spain
| | - María Clara Soto-Bernardini
- Instituto Tecnológico de Costa Rica (TEC), Centro de Investigación en Biotecnología (CIB), Escuela de Biología, Cartago, Costa Rica
| | - Jordi Calderó
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Markus H Schwab
- Institute of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany.,Center for Systems Neuroscience (ZSN), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Josep E Esquerda
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida-Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
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23
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Voltage-Gated Calcium Influx Modifies Cholinergic Inhibition of Inner Hair Cells in the Immature Rat Cochlea. J Neurosci 2018; 38:5677-5687. [PMID: 29789373 DOI: 10.1523/jneurosci.0230-18.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/14/2018] [Accepted: 05/16/2018] [Indexed: 11/21/2022] Open
Abstract
Until postnatal day (P) 12, inner hair cells of the rat cochlea are invested with both afferent and efferent synaptic connections. With the onset of hearing at P12, the efferent synapses disappear, and afferent (ribbon) synapses operate with greater efficiency. This change coincides with increased expression of voltage-gated potassium channels, the loss of calcium-dependent electrogenesis, and the onset of graded receptor potentials driven by sound. The transient efferent synapses include near-membrane postsynaptic cisterns thought to regulate calcium influx through the hair cell's α9-containing and α10-containing nicotinic acetylcholine receptors. This influx activates small-conductance Ca2+-activated K+ (SK) channels. Serial-section electron microscopy of inner hair cells from two 9-d-old (male) rat pups revealed many postsynaptic efferent cisterns and presynaptic afferent ribbons whose average minimal separation in five cells ranged from 1.1 to 1.7 μm. Efferent synaptic function was studied in rat pups (age, 7-9 d) of either sex. The duration of these SK channel-mediated IPSCs was increased by enhanced calcium influx through L-type voltage-gated channels, combined with ryanodine-sensitive release from internal stores-presumably the near-membrane postsynaptic cistern. These data support the possibility that inner hair cell calcium electrogenesis modulates the efficacy of efferent inhibition during the maturation of inner hair cell synapses.SIGNIFICANCE STATEMENT Strict calcium buffering is essential for cellular function. This problem is especially acute for compact hair cells where increasing cytoplasmic calcium promotes the opposing functions of closely adjoining afferent and efferent synapses. The near-membrane postsynaptic cistern at efferent synapses segregates synaptic calcium signals by acting as a dynamic calcium store. The hair cell serves as an informative model for synapses with postsynaptic cisterns (C synapses) found in central neurons.
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Bertuzzi M, Ampatzis K. Spinal cholinergic interneurons differentially control motoneuron excitability and alter the locomotor network operational range. Sci Rep 2018; 8:1988. [PMID: 29386582 PMCID: PMC5792632 DOI: 10.1038/s41598-018-20493-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/19/2018] [Indexed: 11/09/2022] Open
Abstract
While cholinergic neuromodulation is important for locomotor circuit operation, the specific neuronal mechanisms that acetylcholine employs to regulate and fine-tune the speed of locomotion are largely unknown. Here, we show that cholinergic interneurons are present in the zebrafish spinal cord and differentially control the excitability of distinct classes of motoneurons (slow, intermediate and fast) in a muscarinic dependent manner. Moreover, we reveal that m2-type muscarinic acetylcholine receptors (mAChRs) are present in fast and intermediate motoneurons, but not in the slow motoneurons, and that their activation decreases neuronal firing. We also reveal a strong correlation between the muscarinic receptor configuration on motoneurons and the ability of the animals to locomote at different speeds, which might serve as a plasticity mechanism to alter the operational range of the locomotor networks. These unexpected findings provide new insights into the functional flexibility of motoneurons and how they execute locomotion at different speeds.
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Affiliation(s)
- Maria Bertuzzi
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden
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25
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Experimental Design and Data Analysis Issues Contribute to Inconsistent Results of C-Bouton Changes in Amyotrophic Lateral Sclerosis. eNeuro 2017; 4:eN-FTR-0281-16. [PMID: 28101533 PMCID: PMC5241941 DOI: 10.1523/eneuro.0281-16.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/23/2016] [Accepted: 12/26/2016] [Indexed: 12/12/2022] Open
Abstract
The possible presence of pathological changes in cholinergic synaptic inputs [cholinergic boutons (C-boutons)] is a contentious topic within the ALS field. Conflicting data reported on this issue makes it difficult to assess the roles of these synaptic inputs in ALS. Our objective was to determine whether the reported changes are truly statistically and biologically significant and why replication is problematic. This is an urgent question, as C-boutons are an important regulator of spinal motoneuron excitability, and pathological changes in motoneuron excitability are present throughout disease progression. Using male mice of the SOD1-G93A high-expresser transgenic (G93A) mouse model of ALS, we examined C-boutons on spinal motoneurons. We performed histological analysis at high statistical power, which showed no difference in C-bouton size in G93A versus wild-type motoneurons throughout disease progression. In an attempt to examine the underlying reasons for our failure to replicate reported changes, we performed further histological analyses using several variations on experimental design and data analysis that were reported in the ALS literature. This analysis showed that factors related to experimental design, such as grouping unit, sampling strategy, and blinding status, potentially contribute to the discrepancy in published data on C-bouton size changes. Next, we systematically analyzed the impact of study design variability and potential bias on reported results from experimental and preclinical studies of ALS. Strikingly, we found that practices such as blinding and power analysis are not systematically reported in the ALS field. Protocols to standardize experimental design and minimize bias are thus critical to advancing the ALS field.
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26
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Casanovas A, Salvany S, Lahoz V, Tarabal O, Piedrafita L, Sabater R, Hernández S, Calderó J, Esquerda JE. Neuregulin 1-ErbB module in C-bouton synapses on somatic motor neurons: molecular compartmentation and response to peripheral nerve injury. Sci Rep 2017; 7:40155. [PMID: 28065942 PMCID: PMC5220293 DOI: 10.1038/srep40155] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/02/2016] [Indexed: 12/30/2022] Open
Abstract
The electric activity of lower motor neurons (MNs) appears to play a role in determining cell-vulnerability in MN diseases. MN excitability is modulated by cholinergic inputs through C-type synaptic boutons, which display an endoplasmic reticulum-related subsurface cistern (SSC) adjacent to the postsynaptic membrane. Besides cholinergic molecules, a constellation of proteins involved in different signal-transduction pathways are clustered at C-type synaptic sites (M2 muscarinic receptors, Kv2.1 potassium channels, Ca2+ activated K+ [SK] channels, and sigma-1 receptors [S1R]), but their collective functional significance so far remains unknown. We have previously suggested that neuregulin-1 (NRG1)/ErbBs-based retrograde signalling occurs at this synapse. To better understand signalling through C-boutons, we performed an analysis of the distribution of C-bouton-associated signalling proteins. We show that within SSC, S1R, Kv2.1 and NRG1 are clustered in highly specific, non-overlapping, microdomains, whereas ErbB2 and ErbB4 are present in the adjacent presynaptic compartment. This organization may define highly ordered and spatially restricted sites for different signal-transduction pathways. SSC associated proteins are disrupted in axotomised MNs together with the activation of microglia, which display a positive chemotactism to C-bouton sites. This indicates that C-bouton associated molecules are also involved in neuroinflammatory signalling in diseased MNs, emerging as new potential therapeutic targets.
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Affiliation(s)
- Anna Casanovas
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Sara Salvany
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Víctor Lahoz
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Olga Tarabal
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Raimundo Sabater
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Sara Hernández
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Jordi Calderó
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
| | - Josep E. Esquerda
- Departament de Medicina Experimental, Patologia Neuromuscular Experimental, Facultat de Medicina, Universitat de Lleida/IRBLLEIDA, Av. Rovira Roure 80, 25198 Lleida, Catalonia, Spain
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27
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Abstract
The sigma-1 (σ1) receptor has been associated with regulation of intracellular Ca2+ homeostasis, several cellular signaling pathways, and inter-organelle communication, in part through its chaperone activity. In vivo, agonists of the σ1 receptor enhance brain plasticity, with particularly well-described impact on learning and memory. Under pathological conditions, σ1 receptor agonists can induce cytoprotective responses. These protective responses comprise various complementary pathways that appear to be differentially engaged according to pathological mechanism. Recent studies have highlighted the efficacy of drugs that act through the σ1 receptor to mitigate symptoms associated with neurodegenerative disorders with distinct mechanisms of pathogenesis. Here, we will review genetic and pharmacological evidence of σ1 receptor engagement in learning and memory disorders, cognitive impairment, and neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Huntington's disease.
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Affiliation(s)
- Tangui Maurice
- INSERM U1198, University of Montpellier, Montpellier, 34095, France.
| | - Nino Goguadze
- INSERM U1198, University of Montpellier, Montpellier, 34095, France
- Institute of Chemical Biology, Ilia State University, Tbilisi, 0162, Georgia
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28
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Mavlyutov TA, Baker EM, Losenegger TM, Kim JR, Torres B, Epstein ML, Ruoho AE. The Sigma-1 Receptor-A Therapeutic Target for the Treatment of ALS? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:255-265. [PMID: 28315276 DOI: 10.1007/978-3-319-50174-1_17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The membrane bound 223 amino acid Sigma-1 Receptor (S1R) serves as a molecular chaperone and functional regulator of many signaling proteins. Spinal cord motor neuron activation occurs, in part, via large ventral horn cholinergic synapses called C-boutons/C-terminals. Chronic excitation of motor neurons and alterations in C-terminals has been associated with Amyotrophic Lateral Sclerosis (ALS ). The S1R has an important role in regulating motor neuron function. High levels of the S1R are localized in postsynaptic endoplasmic reticulum (ER) subsurface cisternae within 10-20 nm of the plasma membrane that contain muscarinic type 2 acetylcholine receptors (M2AChR), calcium activated potassium channels (Kv2.1) and slow potassium (SK) channels. An increase in action potentials in the S1R KO mouse motor neurons indicates a critical role for the S1R as a "brake" on motor neuron function possibly via calcium dependent hyperpolarization mechanisms involving the aforementioned potassium channels. The longevity of SOD-1/S1R KO ALS mice is significantly reduced compared to SOD-1/WT ALS controls. The S1R colocalizes in C-terminals with Indole(ethyl)amine-N-methyl transferase (INMT ), the enzyme that produces the S1R agonist , N,N'- dimethyltryptamine (DMT). INMT methylation can additionally neutralize endogenous toxic sulfur and selenium derivatives thus providing functional synergism with DMT to reduce oxidative stress in motor neurons . Small molecule activation of the S1R and INMT thus provides a possible therapeutic strategy to treat ALS .
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Affiliation(s)
- Timur A Mavlyutov
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Erin M Baker
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Tasher M Losenegger
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Jaimie R Kim
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Brian Torres
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Miles L Epstein
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Arnold E Ruoho
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
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29
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Mancuso R, Navarro X. Sigma-1 Receptor in Motoneuron Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:235-254. [PMID: 28315275 DOI: 10.1007/978-3-319-50174-1_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS ) is a neurodegenerative disease affecting spinal cord and brain motoneurons , leading to paralysis and early death. Multiple etiopathogenic mechanisms appear to contribute in the development of ALS , including glutamate excitotoxicity, oxidative stress , protein misfolding, mitochondrial defects, impaired axonal transport, inflammation and glial cell alterations. The Sigma-1 receptor is highly expressed in motoneurons of the spinal cord, particularly enriched in the endoplasmic reticulum (ER) at postsynaptic cisternae of cholinergic C-terminals. Several evidences point to participation of Sigma-1R alterations in motoneuron degeneration. Thus, mutations of the transmembrane domain of the Sigma-1R have been described in familial ALS cases. Interestingly, Sigma-1R KO mice display muscle weakness and motoneuron loss. On the other hand, Sigma-1R agonists promote neuroprotection and neurite elongation through activation of protein kinase C on motoneurons in vitro and in vivo after ventral root avulsion. Remarkably, treatment of SOD1 mice, the most usual animal model of ALS , with Sigma-1R agonists resulted in significantly enhanced motoneuron function and preservation, and increased animal survival. Sigma-1R activation also reduced microglial reactivity and increased the glial expression of neurotrophic factors. Two main interconnected mechanisms seem to underlie the effects of Sigma-1R manipulation on motoneurons: modulation of neuronal excitability and regulation of calcium homeostasis. In addition, Sigma-1R also contributes to regulating protein degradation, and reducing oxidative stress. Therefore, the multi-functional nature of the Sigma-1R represents an attractive target for treating aspects of ALS and other motoneuron diseases .
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Affiliation(s)
- Renzo Mancuso
- Center for Biological Sciences, University of Southampton, Southampton General Hospital, SO16 6YD, Southampton, UK
| | - Xavier Navarro
- Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain.
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30
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Ruegsegger C, Maharjan N, Goswami A, Filézac de L'Etang A, Weis J, Troost D, Heller M, Gut H, Saxena S. Aberrant association of misfolded SOD1 with Na(+)/K(+)ATPase-α3 impairs its activity and contributes to motor neuron vulnerability in ALS. Acta Neuropathol 2016; 131:427-51. [PMID: 26619836 DOI: 10.1007/s00401-015-1510-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 11/03/2015] [Accepted: 11/14/2015] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult onset progressive motor neuron disease with no cure. Transgenic mice overexpressing familial ALS associated human mutant SOD1 are a commonly used model for examining disease mechanisms. Presently, it is well accepted that alterations in motor neuron excitability and spinal circuits are pathological hallmarks of ALS, but the underlying molecular mechanisms remain unresolved. Here, we sought to understand whether the expression of mutant SOD1 protein could contribute to altering processes governing motor neuron excitability. We used the conformation specific antibody B8H10 which recognizes a misfolded state of SOD1 (misfSOD1) to longitudinally identify its interactome during early disease stage in SOD1G93A mice. This strategy identified a direct isozyme-specific association of misfSOD1 with Na(+)/K(+)ATPase-α3 leading to the premature impairment of its ATPase activity. Pharmacological inhibition of Na(+)/K(+)ATPase-α3 altered glutamate receptor 2 expression, modified cholinergic inputs and accelerated disease pathology. After mapping the site of direct association of misfSOD1 with Na(+)/K(+)ATPase-α3 onto a 10 amino acid stretch that is unique to Na(+)/K(+)ATPase-α3 but not found in the closely related Na(+)/K(+)ATPase-α1 isozyme, we generated a misfSOD1 binding deficient, but fully functional Na(+)/K(+)ATPase-α3 pump. Adeno associated virus (AAV)-mediated expression of this chimeric Na(+)/K(+)ATPase-α3 restored Na(+)/K(+)ATPase-α3 activity in the spinal cord, delayed pathological alterations and prolonged survival of SOD1G93A mice. Additionally, altered Na(+)/K(+)ATPase-α3 expression was observed in the spinal cord of individuals with sporadic and familial ALS. A fraction of sporadic ALS cases also presented B8H10 positive misfSOD1 immunoreactivity, suggesting that similar mechanism might contribute to the pathology.
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Affiliation(s)
- Céline Ruegsegger
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Niran Maharjan
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Anand Goswami
- Institute of Neuropathology, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital, Aachen, Germany
| | - Audrey Filézac de L'Etang
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
- Department of Neuroscience, Genentech, Inc., South San Francisco, California, USA
| | - Joachim Weis
- Institute of Neuropathology, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital, Aachen, Germany
| | - Dirk Troost
- Division of Neuropathology, Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Manfred Heller
- Department of Clinical Research, Inselspital, University of Bern, Bern, Switzerland
| | - Heinz Gut
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, Bern, Switzerland.
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31
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Lasiene J, Komine O, Fujimori-Tonou N, Powers B, Endo F, Watanabe S, Shijie J, Ravits J, Horner P, Misawa H, Yamanaka K. Neuregulin 1 confers neuroprotection in SOD1-linked amyotrophic lateral sclerosis mice via restoration of C-boutons of spinal motor neurons. Acta Neuropathol Commun 2016; 4:15. [PMID: 26891847 PMCID: PMC4758105 DOI: 10.1186/s40478-016-0286-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 02/10/2016] [Indexed: 12/25/2022] Open
Abstract
Introduction Increasing evidence implicates the role of the cell types surrounding motor neurons, such as interneurons and glial cells, in non-cell autonomous neurodegeneration of amyotrophic lateral sclerosis (ALS). C-boutons, the large cholinergic synapses that innervate spinal α-motor neurons to control their excitability, are progressively lost from motor neurons in both human ALS and mutant Cu/Zn superoxide dismutase 1 (SOD1)-ALS mice. Neuregulin-1 (NRG1), a trophic factor implicated in neural development, transmission, and synaptic plasticity, has been reported to localize in the synapse of C-boutons. However, the roles of NRG1 in maintenance of motor neuron health and activity, as well as the functional consequences of its alteration in motor neuron disease, are not fully understood. Results NRG1 was localized to the post-synaptic face of C-boutons and its expression was significantly lost in SOD1-ALS mice and human ALS patients. Losses of NRG1 expression and C-boutons occured almost contemporaneously in SOD1-ALS mice. In addition, expressions of ErbB3 and ErbB4, receptors for NRG1, were reduced in the motor neurons of SOD1-ALS mice. Furthermore, viral-mediated delivery of type III-NRG1 to the spinal cord restored the number of C-boutons and extended the survival time of SOD1-ALS mice. Conclusions These results suggest that maintenance of NRG1-ErbB4/3 axis by supplementation of NRG1 confers neuroprotection in motor neuron disease, partly through the maintenance of C-boutons of spinal motor neurons. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0286-7) contains supplementary material, which is available to authorized users.
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King AE, Woodhouse A, Kirkcaldie MT, Vickers JC. Excitotoxicity in ALS: Overstimulation, or overreaction? Exp Neurol 2016; 275 Pt 1:162-71. [DOI: 10.1016/j.expneurol.2015.09.019] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/30/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022]
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Leroy F, Zytnicki D. Is hyperexcitability really guilty in amyotrophic lateral sclerosis? Neural Regen Res 2015; 10:1413-5. [PMID: 26604899 PMCID: PMC4625504 DOI: 10.4103/1673-5374.165308] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Felix Leroy
- Centre de Neurophysique, Physiologie et Pathologie, UMR 8119, Université Paris Descartes, UMR 8119, 45 rue des Saints-Pères, 752070 Paris Cedex 06, France
| | - Daniel Zytnicki
- Centre de Neurophysique, Physiologie et Pathologie, UMR 8119, Université Paris Descartes, UMR 8119, 45 rue des Saints-Pères, 752070 Paris Cedex 06, France
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Abstract
UNLABELLED Hearing loss among the elderly correlates with diminished social, mental, and physical health. Age-related cochlear cell death does occur, but growing anatomical evidence suggests that synaptic rearrangements on sensory hair cells also contribute to auditory functional decline. Here we present voltage-clamp recordings from inner hair cells of the C57BL/6J mouse model of age-related hearing loss, which reveal that cholinergic synaptic inputs re-emerge during aging. These efferents are functionally inhibitory, using the same ionic mechanisms as do efferent contacts present transiently before the developmental onset of hearing. The strength of efferent inhibition of inner hair cells increases with hearing threshold elevation. These data indicate that the aged cochlea regains features of the developing cochlea and that efferent inhibition of the primary receptors of the auditory system re-emerges with hearing impairment. SIGNIFICANCE STATEMENT Synaptic changes in the auditory periphery are increasingly recognized as important factors in hearing loss. To date, anatomical work has described the loss of afferent contacts from cochlear hair cells. However, relatively little is known about the efferent innervation of the cochlea during hearing loss. We performed intracellular recordings from mouse inner hair cells across the lifespan and show that efferent innervation of inner hair cells arises in parallel with the loss of afferent contacts and elevated hearing threshold during aging. These efferent neurons inhibit inner hair cells, raising the possibility that they play a role in the progression of age-related hearing loss.
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Milan L, Courtand G, Cardoit L, Masmejean F, Barrière G, Cazalets JR, Garret M, Bertrand SS. Age-Related Changes in Pre- and Postsynaptic Partners of the Cholinergic C-Boutons in Wild-Type and SOD1G93A Lumbar Motoneurons. PLoS One 2015; 10:e0135525. [PMID: 26305672 PMCID: PMC4549056 DOI: 10.1371/journal.pone.0135525] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/22/2015] [Indexed: 11/19/2022] Open
Abstract
Large cholinergic synaptic terminals known as C-boutons densely innervate the soma and proximal dendrites of motoneurons that are prone to neurodegeneration in amyotrophic lateral sclerosis (ALS). Studies using the Cu/Zn-superoxide dismutase (SOD1) mouse model of ALS have generated conflicting data regarding C-bouton alterations exhibited during ALS pathogenesis. In the present work, a longitudinal study combining immunohistochemistry, biochemical approaches and extra- and intra-cellular electrophysiological recordings revealed that the whole spinal cholinergic system is modified in the SOD1 mouse model of ALS compared to wild type (WT) mice as early as the second postnatal week. In WT motoneurons, both C-bouton terminals and associated M2 postsynaptic receptors presented a complex age-related dynamic that appeared completely disrupted in SOD1 motoneurons. Indeed, parallel to C-bouton morphological alterations, analysis of confocal images revealed a clustering process of M2 receptors during WT motoneuron development and maturation that was absent in SOD1 motoneurons. Our data demonstrated for the first time that the lamina X cholinergic interneurons, the neuronal source of C-boutons, are over-abundant in high lumbar segments in SOD1 mice and are subject to neurodegeneration in the SOD1 animal model. Finally, we showed that early C-bouton system alterations have no physiological impact on the cholinergic neuromodulation of newborn motoneurons. Altogether, these data suggest a complete reconfiguration of the spinal cholinergic system in SOD1 spinal networks that could be part of the compensatory mechanisms established during spinal development.
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Affiliation(s)
- Léa Milan
- INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
| | - Gilles Courtand
- INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
| | - Laura Cardoit
- INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
| | | | | | | | - Maurice Garret
- INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
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Devlin AC, Burr K, Borooah S, Foster JD, Cleary EM, Geti I, Vallier L, Shaw CE, Chandran S, Miles GB. Human iPSC-derived motoneurons harbouring TARDBP or C9ORF72 ALS mutations are dysfunctional despite maintaining viability. Nat Commun 2015; 6:5999. [PMID: 25580746 PMCID: PMC4338554 DOI: 10.1038/ncomms6999] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/28/2014] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease for which a greater understanding of early disease mechanisms is needed to reveal novel therapeutic targets. We report the use of human induced pluripotent stem cell (iPSC)-derived motoneurons (MNs) to study the pathophysiology of ALS. We demonstrate that MNs derived from iPSCs obtained from healthy individuals or patients harbouring TARDBP or C9ORF72 ALS-causing mutations are able to develop appropriate physiological properties. However, patient iPSC-derived MNs, independent of genotype, display an initial hyperexcitability followed by progressive loss of action potential output and synaptic activity. This loss of functional output reflects a progressive decrease in voltage-activated Na(+) and K(+) currents, which occurs in the absence of overt changes in cell viability. These data implicate early dysfunction or loss of ion channels as a convergent point that may contribute to the initiation of downstream degenerative pathways that ultimately lead to MN loss in ALS.
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Affiliation(s)
- Anna-Claire Devlin
- School of Psychology and Neuroscience, University of St. Andrews, Westburn Lane, St. Andrews KY16 9JP, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
| | - Karen Burr
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
- Centre for Neuroregeneration and Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Shyamanga Borooah
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
- Centre for Neuroregeneration and Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Joshua D. Foster
- School of Psychology and Neuroscience, University of St. Andrews, Westburn Lane, St. Andrews KY16 9JP, UK
| | - Elaine M. Cleary
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
- Centre for Neuroregeneration and Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Imbisaat Geti
- Wellcome Trust-Medical Research Council Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery, University of Cambridge, Cambridge CB2 0XY, UK
| | - Ludovic Vallier
- Wellcome Trust-Medical Research Council Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery, University of Cambridge, Cambridge CB2 0XY, UK
| | - Christopher E. Shaw
- MRC Centre for Neurodegeneration Research, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Siddharthan Chandran
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
- Centre for Neuroregeneration and Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Gareth B. Miles
- School of Psychology and Neuroscience, University of St. Andrews, Westburn Lane, St. Andrews KY16 9JP, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh EH16 4SB, UK
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Mavlyutov TA, Guo LW, Epstein ML, Ruoho AE. Role of the Sigma-1 receptor in Amyotrophic Lateral Sclerosis (ALS). J Pharmacol Sci 2015; 127:10-6. [PMID: 25704013 PMCID: PMC4489701 DOI: 10.1016/j.jphs.2014.12.013] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 12/18/2014] [Accepted: 12/21/2014] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease affecting spinal cord motoneurons (MN) with an associative connection to Frontotemporal Lobar Dementia (FTLD). The endoplasmic reticulum (ER) bound Sigma-1 Receptor (S1R) chaperone protein localizes to specialized ER cisternae within 10 nm of the plasma membrane in spinal cord ventral horn cholinergic post synaptic C-terminals. Removal of the S1R gene in the Superoxide Dismutase-1 (SOD-1) mouse model of ALS exacerbated the neurodegenerative condition and resulted in a significantly reduced longevity when compared to the SOD-1/S1R wild type (WT) mouse. The proposed amelioration of the ALS phenotype by the S1R is likely due to a "brake" on excitation of the MN as evidenced by a reduction in action potential generation in the MN of the WT when compared to the S1R KO mouse MN. Although the precise signal transduction pathway(s) regulated by the S1R in the MN has/have not been elucidated at present, it is likely that direct or indirect functional interactions occur between the S1R in the ER cisternae with voltage gated potassium channels and/or with muscarinic M2 receptor signaling in the post synaptic plasma membrane. Possible mechanisms for regulation of MN excitability by S1R are discussed.
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Affiliation(s)
- Timur A Mavlyutov
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, USA; Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Lian-Wang Guo
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Miles L Epstein
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Arnold E Ruoho
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, USA.
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de Carvalho M, Eisen A, Krieger C, Swash M. Motoneuron firing in amyotrophic lateral sclerosis (ALS). Front Hum Neurosci 2014; 8:719. [PMID: 25294995 PMCID: PMC4170108 DOI: 10.3389/fnhum.2014.00719] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/27/2014] [Indexed: 01/09/2023] Open
Abstract
Amyotrophic lateral sclerosis is an inexorably progressive neurodegenerative disorder involving the classical motor system and the frontal effector brain, causing muscular weakness and atrophy, with variable upper motor neuron signs and often an associated fronto-temporal dementia. The physiological disturbance consequent on the motor system degeneration is beginning to be well understood. In this review we describe aspects of the motor cortical, neuronal, and lower motor neuron dysfunction. We show how studies of the changes in the pattern of motor unit firing help delineate the underlying pathophysiological disturbance as the disease progresses. Such studies are beginning to illuminate the underlying disordered pathophysiological processes in the disease, and are important in designing new approaches to therapy and especially for clinical trials.
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Affiliation(s)
- Mamede de Carvalho
- Institute of Physiology and Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon Lisbon, Portugal ; Department of Neurosciences, Hospital Santa Maria, Faculty of Medicine, University of Lisbon Lisbon, Portugal
| | - Andrew Eisen
- Emeritus Professor of Neurology, University of British Columbia Vancouver, BC, Canada
| | - Charles Krieger
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby BC, Canada ; Department of Medicine (Neurology), University of British Columbia, Vancouver BC, Canada
| | - Michael Swash
- Institute of Physiology and Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon Lisbon, Portugal ; Department of Neurosciences, Hospital Santa Maria, Faculty of Medicine, University of Lisbon Lisbon, Portugal ; Institute of Neuroscience, Barts and The London School of Medicine, Queen Mary University of London London, UK
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Deardorff AS, Romer SH, Sonner PM, Fyffe REW. Swimming against the tide: investigations of the C-bouton synapse. Front Neural Circuits 2014; 8:106. [PMID: 25278842 PMCID: PMC4167003 DOI: 10.3389/fncir.2014.00106] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/17/2014] [Indexed: 11/19/2022] Open
Abstract
C-boutons are important cholinergic modulatory loci for state-dependent alterations in motoneuron firing rate. m2 receptors are concentrated postsynaptic to C-boutons, and m2 receptor activation increases motoneuron excitability by reducing the action potential afterhyperpolarization. Here, using an intensive review of the current literature as well as data from our laboratory, we illustrate that C-bouton postsynaptic sites comprise a unique structural/functional domain containing appropriate cellular machinery (a “signaling ensemble”) for cholinergic regulation of outward K+ currents. Moreover, synaptic reorganization at these critical sites has been observed in a variety of pathologic states. Yet despite recent advances, there are still great challenges for understanding the role of C-bouton regulation and dysregulation in human health and disease. The development of new therapeutic interventions for devastating neurological conditions will rely on a complete understanding of the molecular mechanisms that underlie these complex synapses. Therefore, to close this review, we propose a comprehensive hypothetical mechanism for the cholinergic modification of α-MN excitability at C-bouton synapses, based on findings in several well-characterized neuronal systems.
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Affiliation(s)
- Adam S Deardorff
- Boonshoft School of Medicine, Department of Neuroscience, Cell Biology and Physiology, Wright State University Dayton, OH, USA
| | - Shannon H Romer
- Boonshoft School of Medicine, Department of Neuroscience, Cell Biology and Physiology, Wright State University Dayton, OH, USA
| | - Patrick M Sonner
- Boonshoft School of Medicine, Department of Neuroscience, Cell Biology and Physiology, Wright State University Dayton, OH, USA
| | - Robert E W Fyffe
- Boonshoft School of Medicine, Department of Neuroscience, Cell Biology and Physiology, Wright State University Dayton, OH, USA
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Mechanisms involved in spinal cord central synapse loss in a mouse model of spinal muscular atrophy. J Neuropathol Exp Neurol 2014; 73:519-35. [PMID: 24806302 DOI: 10.1097/nen.0000000000000074] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Motoneuron (MN) cell death is the histopathologic hallmark of spinal muscular atrophy (SMA), although MN loss seems to be a late event. Conversely, disruption of afferent synapses on MNs has been shown to occur early in SMA. Using a mouse model of severe SMA (SMNΔ7), we examined the mechanisms involved in impairment of central synapses. We found that MNs underwent progressive degeneration in the course of SMA, with MN loss still occurring at late stages. Loss of afferent inputs to SMA MNs was detected at embryonic stages, long before MN death. Reactive microgliosis and astrogliosis were present in the spinal cord of diseased animals after the onset of MN loss. Ultrastructural observations indicate that dendrites and microglia phagocytose adjacent degenerating presynaptic terminals. Neuronal nitric oxide synthase was upregulated in SMNΔ7 MNs, and there was an increase in phosphorylated myosin light chain expression in synaptic afferents on MNs; these observations implicate nitric oxide in MN deafferentation and suggest that the RhoA/ROCK pathway is activated. Together, our observations suggest that the earliest change occurring in SMNΔ7 mice is the loss of excitatory glutamatergic synaptic inputs to MNs; reduced excitability may enhance their vulnerability to degeneration and death.
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Gallart-Palau X, Tarabal O, Casanovas A, Sábado J, Correa FJ, Hereu M, Piedrafita L, Calderó J, Esquerda JE. Neuregulin-1 is concentrated in the postsynaptic subsurface cistern of C-bouton inputs to α-motoneurons and altered during motoneuron diseases. FASEB J 2014; 28:3618-32. [PMID: 24803543 DOI: 10.1096/fj.13-248583] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
C boutons are large, cholinergic, synaptic terminals that arise from local interneurons and specifically contact spinal α-motoneurons (MNs). C boutons characteristically display a postsynaptic specialization consisting of an endoplasmic reticulum-related subsurface cistern (SSC) of unknown function. In the present work, by using confocal microscopy and ultrastructural immunolabeling, we demonstrate that neuregulin-1 (NRG1) accumulates in the SSC of mouse spinal MNs. We also show that the NRG1 receptors erbB2 and erbB4 are presynaptically localized within C boutons, suggesting that NRG1-based retrograde signaling may occur in this type of synapse. In most of the cranial nuclei, MNs display the same pattern of NRG1 distribution as that observed in spinal cord MNs. Conversely, MNs in oculomotor nuclei, which are spared in amyotrophic lateral sclerosis (ALS), lack both C boutons and SSC-associated NRG1. NRG1 in spinal MNs is developmentally regulated and depends on the maintenance of nerve-muscle interactions, as we show after nerve transection experiments. Changes in NRG1 in C boutons were also investigated in mouse models of MN diseases: i.e., spinal muscular atrophy (SMNΔ7) and ALS (SOD1(G93A)). In both models, a transient increase in NRG1 in C boutons occurs during disease progression. These data increase our understanding of the role of C boutons in MN physiology and pathology.
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Affiliation(s)
- Xavier Gallart-Palau
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Javier Sábado
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Francisco J Correa
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Marta Hereu
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cellular, Departament de Medicina Experimental, Facultat de Medicina, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Universitat de Lleida, Lleida, Catalonia, Spain
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THEME 9IN VIVOEXPERIMENTAL MODELS. Amyotroph Lateral Scler Frontotemporal Degener 2013. [DOI: 10.3109/21678421.2013.838424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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C1q induction and global complement pathway activation do not contribute to ALS toxicity in mutant SOD1 mice. Proc Natl Acad Sci U S A 2013; 110:E4385-92. [PMID: 24170856 DOI: 10.1073/pnas.1318309110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Accumulating evidence from mice expressing ALS-causing mutations in superoxide dismutase (SOD1) has implicated pathological immune responses in motor neuron degeneration. This includes microglial activation, lymphocyte infiltration, and the induction of C1q, the initiating component of the classic complement system that is the protein-based arm of the innate immune response, in motor neurons of multiple ALS mouse models expressing dismutase active or inactive SOD1 mutants. Robust induction early in disease course is now identified for multiple complement components (including C1q, C4, and C3) in spinal cords of SOD1 mutant-expressing mice, consistent with initial intraneuronal C1q induction, followed by global activation of the complement pathway. We now test if this activation is a mechanistic contributor to disease. Deletion of the C1q gene in mice expressing an ALS-causing mutant in SOD1 to eliminate C1q induction, and complement cascade activation that follows from it, is demonstrated to produce changes in microglial morphology accompanied by enhanced loss, not retention, of synaptic densities during disease. C1q-dependent synaptic loss is shown to be especially prominent for cholinergic C-bouton nerve terminal input onto motor neurons in affected C1q-deleted SOD1 mutant mice. Nevertheless, overall onset and progression of disease are unaffected in C1q- and C3-deleted ALS mice, thus establishing that C1q induction and classic or alternative complement pathway activation do not contribute significantly to SOD1 mutant-mediated ALS pathogenesis in mice.
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Spinal inhibitory circuits and their role in motor neuron degeneration. Neuropharmacology 2013; 82:101-7. [PMID: 24157492 DOI: 10.1016/j.neuropharm.2013.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 10/01/2013] [Accepted: 10/04/2013] [Indexed: 12/12/2022]
Abstract
In the spinal cord neuronal activity is controlled by the balance between excitatory and inhibitory neurotransmission, mediated mainly by the neurotransmitters glutamate and GABA/glycine, respectively. Alterations of this equilibrium have been associated with spinal motor neuron hyperexcitability and degeneration, which can be induced by excitotoxicity or by decreasing inhibitory neurotransmission. Here we review the ventral horn neuronal network and the possible involvement of inhibitory circuits in the mechanisms of degeneration of motor neurons characteristic of amyotrophic lateral sclerosis (ALS). Whereas glutamate mediated excitotoxicity seems to be an important factor, recent experimental and histopathological evidence argue in favor of a decreased activity of the inhibitory circuits controlling motor neuron excitability, mainly the recurrent inhibition exerted by Renshaw cells. A decreased Renshaw cell activity may be caused by cell loss or by a reduction of its inhibitory action secondary to a decreased excitation from cholinergic interneurons. Ultimately, inhibitory failure by either mechanism might lead to motor neuron degeneration, and this suggests inhibitory circuits and Renshaw cells as pharmacologic targets for ALS treatment.
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Saxena S, Roselli F, Singh K, Leptien K, Julien JP, Gros-Louis F, Caroni P. Neuroprotection through Excitability and mTOR Required in ALS Motoneurons to Delay Disease and Extend Survival. Neuron 2013; 80:80-96. [DOI: 10.1016/j.neuron.2013.07.027] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2013] [Indexed: 12/13/2022]
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Vinsant S, Mansfield C, Jimenez-Moreno R, Del Gaizo Moore V, Yoshikawa M, Hampton TG, Prevette D, Caress J, Oppenheim RW, Milligan C. Characterization of early pathogenesis in the SOD1(G93A) mouse model of ALS: part II, results and discussion. Brain Behav 2013; 3:431-57. [PMID: 24381813 PMCID: PMC3869683 DOI: 10.1002/brb3.142] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 12/12/2022] Open
Abstract
Pathological events are well characterized in amyotrophic lateral sclerosis (ALS) mouse models, but review of the literature fails to identify a specific initiating event that precipitates disease pathology. There is now growing consensus in the field that axon and synapses are first cellular sites of degeneration, but controversy exists over whether axon and synapse loss is initiated autonomously at those sites or by pathology in the cell body, in nonneuronal cells or even in nonmotoneurons (MNs). Previous studies have identified pathological events in the mutant superoxide dismutase 1 (SOD1) models involving spinal cord, peripheral axons, neuromuscular junctions (NMJs), or muscle; however, few studies have systematically examined pathogenesis at multiple sites in the same study. We have performed ultrastructural examination of both central and peripheral components of the neuromuscular system in the SOD1(G93A) mouse model of ALS. Twenty percent of MNs undergo degeneration by P60, but NMJ innervation in fast fatigable muscles is reduced by 40% by P30. Gait alterations and muscle weakness were also found at P30. There was no change in axonal transport prior to initial NMJ denervation. Mitochondrial morphological changes are observed at P7 and become more prominent with disease progression. At P30 there was a significant decrease in excitatory axo-dendritic and axo-somatic synapses with an increase in C-type axo-somatic synapses. Our study examined early pathology in both peripheral and central neuromuscular system. The muscle denervation is associated with functional motor deficits and begins during the first postnatal month in SOD1(G93A) mice. Physiological dysfunction and pathology in the mitochondria of synapses and MN soma and dendrites occur, and disease onset in these animals begins more than 2 months earlier than originally thought. This information may be valuable for designing preclinical trials that are more likely to impact disease onset and progression.
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Affiliation(s)
- Sharon Vinsant
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Mansfield
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ramon Jimenez-Moreno
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - Masaaki Yoshikawa
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - David Prevette
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - James Caress
- Department of Neurology and the ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ronald W Oppenheim
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Milligan
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
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47
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Mavlyutov TA, Epstein ML, Verbny YI, Huerta MS, Zaitoun I, Ziskind-Conhaim L, Ruoho AE. Lack of sigma-1 receptor exacerbates ALS progression in mice. Neuroscience 2013; 240:129-34. [PMID: 23458708 PMCID: PMC3665351 DOI: 10.1016/j.neuroscience.2013.02.035] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 02/02/2013] [Accepted: 02/15/2013] [Indexed: 11/16/2022]
Abstract
The function of the sigma-1 receptor (S1R) has been implicated in modulating the activity of various ion channels. In the CNS S1R is enriched in cholinergic postsynaptic densities in spinal cord motoneurons (MNs). Mutations in S1R have been found in familial cases of amyotrophic lateral sclerosis (ALS). In this study we show that a knockout of S1R in the SOD1*G93A mouse model of ALS significantly reduces longevity (end stage). Electrophysiological experiments demonstrate that MN of mice lacking S1R exhibit increased excitability. Taken together the data suggest the S1R acts as a brake on excitability, an effect that might enhance longevity in an ALS mouse model.
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Affiliation(s)
- T A Mavlyutov
- Department of Neuroscience, University of Wisconsin, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
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48
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Witts EC, Zagoraiou L, Miles GB. Anatomy and function of cholinergic C bouton inputs to motor neurons. J Anat 2013; 224:52-60. [PMID: 23701140 DOI: 10.1111/joa.12063] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2013] [Indexed: 12/11/2022] Open
Abstract
Motor control circuitry of the central nervous system must be flexible so that motor behaviours can be adapted to suit the varying demands of different states, developmental stages, and environments. Flexibility in motor control is largely provided by neuromodulatory systems which can adjust the output of motor circuits by modulating the properties and connectivity of neurons within them. The spinal circuitry which controls locomotion is subject to a range of neuromodulatory influences, including some which are intrinsic to the spinal cord. One such intrinsic neuromodulatory system, for which a wealth of anatomical information has recently been combined with new physiological data, is the C bouton system. C boutons are large, cholinergic inputs to motor neurons which were first described over 40 years ago but whose source and function have until recently remained a mystery. In this review we discuss how the convergence of anatomical, molecular genetic and physiological data has recently led to significant advances in our understanding of this unique neuromodulatory system. We also highlight evidence that C boutons are involved in spinal cord injury and disease, revealing their potential as targets for novel therapeutic strategies.
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Affiliation(s)
- Emily C Witts
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK
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49
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Prause J, Goswami A, Katona I, Roos A, Schnizler M, Bushuven E, Dreier A, Buchkremer S, Johann S, Beyer C, Deschauer M, Troost D, Weis J. Altered localization, abnormal modification and loss of function of Sigma receptor-1 in amyotrophic lateral sclerosis. Hum Mol Genet 2013; 22:1581-600. [PMID: 23314020 DOI: 10.1093/hmg/ddt008] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Intracellular accumulations of mutant, misfolded proteins are major pathological hallmarks of amyotrophic lateral sclerosis (ALS) and related disorders. Recently, mutations in Sigma receptor 1 (SigR1) have been found to cause a form of ALS and frontotemporal lobar degeneration (FTLD). Our goal was to pinpoint alterations and modifications of SigR1 in ALS and to determine how these changes contribute to the pathogenesis of ALS. In the present study, we found that levels of the SigR1 protein were reduced in lumbar ALS patient spinal cord. SigR1 was abnormally accumulated in enlarged C-terminals and endoplasmic reticulum (ER) structures of alpha motor neurons. These accumulations co-localized with the 20s proteasome subunit. SigR1 accumulations were also observed in SOD1 transgenic mice, cultured ALS-8 patient's fibroblasts with the P56S-VAPB mutation and in neuronal cell culture models. Along with the accumulation of SigR1 and several other proteins involved in protein quality control, severe disturbances in the unfolded protein response and impairment of protein degradation pathways were detected in the above-mentioned cell culture systems. Furthermore, shRNA knockdown of SigR1 lead to deranged calcium signaling and caused abnormalities in ER and Golgi structures in cultured NSC-34 cells. Finally, pharmacological activation of SigR1 induced the clearance of mutant protein aggregates in these cells. Our results support the notion that SigR1 is abnormally modified and contributes to the pathogenesis of ALS.
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Affiliation(s)
- J Prause
- Institute of Neuropathology, RWTH Aachen University and JARA Brain Translational Medicine, Pauwelsstr. 30, 52074 Aachen, Germany
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50
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Wootz H, Fitzsimons-Kantamneni E, Larhammar M, Rotterman TM, Enjin A, Patra K, André E, Van Zundert B, Kullander K, Alvarez FJ. Alterations in the motor neuron-renshaw cell circuit in the Sod1(G93A) mouse model. J Comp Neurol 2013; 521:1449-69. [PMID: 23172249 DOI: 10.1002/cne.23266] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 09/14/2012] [Accepted: 11/06/2012] [Indexed: 12/12/2022]
Abstract
Motor neurons become hyperexcitable during progression of amyotrophic lateral sclerosis (ALS). This abnormal firing behavior has been explained by changes in their membrane properties, but more recently it has been suggested that changes in premotor circuits may also contribute to this abnormal activity. The specific circuits that may be altered during development of ALS have not been investigated. Here we examined the Renshaw cell recurrent circuit that exerts inhibitory feedback control on motor neuron firing. Using two markers for Renshaw cells (calbindin and cholinergic nicotinic receptor subunit alpha2 [Chrna2]), two general markers for motor neurons (NeuN and vesicular acethylcholine transporter [VAChT]), and two markers for fast motor neurons (Chondrolectin and calcitonin-related polypeptide alpha [Calca]), we analyzed the survival and connectivity of these cells during disease progression in the Sod1(G93A) mouse model. Most calbindin-immunoreactive (IR) Renshaw cells survive to end stage but downregulate postsynaptic Chrna2 in presymptomatic animals. In motor neurons, some markers are downregulated early (NeuN, VAChT, Chondrolectin) and others at end stage (Calca). Early downregulation of presynaptic VAChT and Chrna2 was correlated with disconnection from Renshaw cells as well as major structural abnormalities of motor axon synapses inside the spinal cord. Renshaw cell synapses on motor neurons underwent more complex changes, including transitional sprouting preferentially over remaining NeuN-IR motor neurons. We conclude that the loss of presynaptic motor axon input on Renshaw cells occurs at early stages of ALS and disconnects the recurrent inhibitory circuit, presumably resulting in diminished control of motor neuron firing. J. Comp. Neurol. 521:1449-1469, 2013. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Hanna Wootz
- Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden
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