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Analysis of the Expression and Subcellular Distribution of eEF1A1 and eEF1A2 mRNAs during Neurodevelopment. Cells 2022; 11:cells11121877. [PMID: 35741005 PMCID: PMC9220863 DOI: 10.3390/cells11121877] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 12/04/2022] Open
Abstract
Neurodevelopment is accompanied by a precise change in the expression of the translation elongation factor 1A variants from eEF1A1 to eEF1A2. These are paralogue genes that encode 92% identical proteins in mammals. The switch in the expression of eEF1A variants has been well studied in mouse motor neurons, which solely express eEF1A2 by four weeks of postnatal development. However, changes in the subcellular localization of eEF1A variants during neurodevelopment have not been studied in detail in other neuronal types because antibodies lack perfect specificity, and immunofluorescence has a low sensitivity. In hippocampal neurons, eEF1A is related to synaptic plasticity and memory consolidation, and decreased eEF1A expression is observed in the hippocampus of Alzheimer's patients. However, the specific variant involved in these functions is unknown. To distinguish eEF1A1 from eEF1A2 expression, we have designed single-molecule fluorescence in-situ hybridization probes to detect either eEF1A1 or eEF1A2 mRNAs in cultured primary hippocampal neurons and brain tissues. We have developed a computational framework, ARLIN (analysis of RNA localization in neurons), to analyze and compare the subcellular distribution of eEF1A1 and eEF1A2 mRNAs at specific developmental stages and in mature neurons. We found that eEF1A1 and eEF1A2 mRNAs differ in expression and subcellular localization over neurodevelopment, and eEF1A1 mRNAs localize in dendrites and synapses during dendritogenesis and synaptogenesis. Interestingly, mature hippocampal neurons coexpress both variant mRNAs, and eEF1A1 remains the predominant variant in dendrites.
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Chong PF, Torisu H, Yasumoto S, Okumura A, Mori H, Sato T, Kimura J, Ohga S, Tanaka-Taya K, Kira R. Clinical and electrophysiological features of acute flaccid myelitis: A national cohort study. Clin Neurophysiol 2021; 132:2456-2463. [PMID: 34454273 DOI: 10.1016/j.clinph.2021.07.013] [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: 07/02/2020] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To summarize the neurophysiological properties of acute flaccid myelitis (AFM) and evaluate limb-based motor outcomes. METHODS Nerve conduction studies (NCS) in 49 patients (21 females, 28 males; median age = 52 m) with AFM (median = 7 d after onset; range 1-122 d) were reviewed. Neurophysiological findings, together with treatment and prognosis, and neurophysiology-neuroimaging correlations were analyzed. RESULTS The findings indicated that 64% of paralytic limbs during the acute stage (≤14 d after onset) showed diminished or absent compound muscle action potentials (CMAPs), 79% showed normal motor nerve conduction velocities, 55% showed decreased persistence or absent F-waves, and 95% showed normal sensory nerve conduction velocities. The rate of CMAP abnormalities increased from 41% on days 1-2 to 83% on days 13-14. The reduction in CMAP amplitude was correlated with weaker muscle strength at both the peak neurological deficit and the last follow-up. The baseline limb-based muscle strength at nadir and anterior horn-localized magnetic resonance imaging lesions at recovery stage (>14 d) were strong predictors of outcome at the last follow-up. CONCLUSIONS AFM typically shows neurophysiological features of neuronopathy. SIGNIFICANCE NCS is probably useful in the diagnosis and evaluation of AFM.
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Affiliation(s)
- Pin Fee Chong
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan; Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Torisu
- Section of Pediatrics, Department of Medicine, Fukuoka Dental College, Fukuoka, Japan
| | - Sawa Yasumoto
- Medical Education Center, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Akihisa Okumura
- Department of Pediatrics, Aichi Medical University, Nagakute, Aichi, Japan
| | - Harushi Mori
- Department of Radiology, Jichi Medical University, Tochigi, Japan
| | - Tatsuharu Sato
- Department of Pediatrics, Nagasaki University Hospital, Nagasaki, Japan
| | - Jun Kimura
- Division of Clinical Electrophysiology, Department of Neurology, University of Iowa Health Care, Iowa City, IA, USA
| | - Shouichi Ohga
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Keiko Tanaka-Taya
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Ryutaro Kira
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan.
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Bourdi M, Rudloff U, Patnaik S, Marugan J, Terse PS. Safety assessment of metarrestin in dogs: A clinical candidate targeting a subnuclear structure unique to metastatic cancer cells. Regul Toxicol Pharmacol 2020; 116:104716. [PMID: 32619635 PMCID: PMC8378239 DOI: 10.1016/j.yrtph.2020.104716] [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] [Received: 02/14/2020] [Revised: 05/09/2020] [Accepted: 06/16/2020] [Indexed: 11/28/2022]
Abstract
Pancreatic cancer is a leading cause of cancer-related deaths in the U.S. Ninety percent of patients with stage IV pancreatic cancer die within one year of diagnosis due to complications of metastasis. A metastatic potential of cancer cells has been shown to be closely associated with formation of perinucleolar compartment (PNC). Metarrestin, a first-in-class PNC inhibitor, was evaluated for its toxicity, toxicokinetics, and safety pharmacology in beagle dogs following every other day oral (capsule) administration for 28 days to support its introduction into clinical trials. The study consisted of four dose groups: vehicle; 0.25, 0.75 and 1.50 mg/kg/dose. Metarrestin reached its maximum concentration in blood at 3 h (overall median Tmax) across all doses with a mean t1/2 over 168 h of 55.5 h. Dose dependent increase in systemic exposure (Cmax and AUClast) with no sex difference was observed on days 1 and 27. Metarrestin accumulated from Day 1 to Day 27 at all dose levels and in both sexes by an overall factor of about 2.34. No mortality occurred during the dosing period; however, treatment-related clinical signs of toxicity consisting of hypoactivity, shaking/shivering, thinness, irritability, salivation, abnormal gait, tremors, ataxia and intermittent seizure-like activity were seen in both sexes at mid and high dose groups. Treatment-related effects on body weight and food consumption were seen at the mid and high dose levels. Safety pharmacology study showed no treatment-related effects on blood pressure, heart rate, corrected QT, PR, RR, or QRS intervals, or respiratory function parameters (respiratory rate, tidal volume, minute volume). There were no histopathological changes observed, with the exception of transient thymic atrophy which was considered to be non-adverse. Based primarily on clinical signs of toxicity, the No Observed Adverse Effect Level (NOAEL) in dogs was considered to be 0.25 mg/kg metarrestin after every other day dosing for 28 days with a mean of male and female Cmax = 82.5 ng/mL and AUClast = 2521 h*ng/mL, on Day 27.
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Affiliation(s)
- Mohammed Bourdi
- National Center for Advancing Translational Sciences, NIH, Rockville, Maryland, USA
| | - Udo Rudloff
- Rare Tumor Initiative, Pediatric Oncology Branch, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences, NIH, Rockville, Maryland, USA
| | - Juan Marugan
- National Center for Advancing Translational Sciences, NIH, Rockville, Maryland, USA
| | - Pramod S Terse
- National Center for Advancing Translational Sciences, NIH, Rockville, Maryland, USA.
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4
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Castets P, Ham DJ, Rüegg MA. The TOR Pathway at the Neuromuscular Junction: More Than a Metabolic Player? Front Mol Neurosci 2020; 13:162. [PMID: 32982690 PMCID: PMC7485269 DOI: 10.3389/fnmol.2020.00162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
The neuromuscular junction (NMJ) is the chemical synapse connecting motor neurons and skeletal muscle fibers. NMJs allow all voluntary movements, and ensure vital functions like breathing. Changes in the structure and function of NMJs are hallmarks of numerous pathological conditions that affect muscle function including sarcopenia, the age-related loss of muscle mass and function. However, the molecular mechanisms leading to the morphological and functional perturbations in the pre- and post-synaptic compartments of the NMJ remain poorly understood. Here, we discuss the role of the metabolic pathway associated to the kinase TOR (Target of Rapamycin) in the development, maintenance and alterations of the NMJ. This is of particular interest as the TOR pathway has been implicated in aging, but its role at the NMJ is still ill-defined. We highlight the respective functions of the two TOR-associated complexes, TORC1 and TORC2, and discuss the role of localized protein synthesis and autophagy regulation in motor neuron terminals and sub-synaptic regions of muscle fibers and their possible effects on NMJ maintenance.
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Affiliation(s)
- Perrine Castets
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Mole AJ, Bell S, Thomson AK, Dissanayake KN, Ribchester RR, Murray LM. Synaptic withdrawal following nerve injury is influenced by postnatal maturity, muscle-specific properties, and the presence of underlying pathology in mice. J Anat 2020; 237:263-274. [PMID: 32311115 PMCID: PMC7369188 DOI: 10.1111/joa.13187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/30/2020] [Accepted: 03/02/2020] [Indexed: 01/13/2023] Open
Abstract
Axonal and synaptic degeneration occur following nerve injury and during disease. Traumatic nerve injury results in rapid fragmentation of the distal axon and loss of synaptic terminals, in a process known as Wallerian degeneration (WD). Identifying and understanding factors that influence the rate of WD is of significant biological and clinical importance, as it will facilitate understanding of the mechanisms of neurodegeneration and identification of novel therapeutic targets. Here, we investigate levels of synaptic loss following nerve injury under a range of conditions, including during postnatal development, in a range of anatomically distinct muscles and in a mouse model of motor neuron disease. By utilising an ex vivo model of nerve injury, we show that synaptic withdrawal is slower during early postnatal development. Significantly more neuromuscular junctions remained fully innervated in the cranial nerve/muscle preparations analysed at P15 than at P25. Furthermore, we demonstrate variability in the level of synaptic withdrawal in response to injury in different muscles, with retraction being slower in abdominal preparations than in cranial muscles across all time points analysed. Importantly, differences between the cranial and thoracoabdominal musculature seen here are not consistent with differences in muscle vulnerability that have been previously reported in mouse models of the childhood motor neuron disease, spinal muscular atrophy (SMA), caused by depletion of survival motor neuron protein (Smn). To further investigate the relationship between synaptic degeneration in SMA and WD, we induced WD in preparations from the Smn2B/− mouse model of SMA. In a disease‐resistant muscle (rostral band of levator auris longus), where there is minimal denervation, there was no change in the level of synaptic loss, which suggests that the process of synaptic withdrawal following injury is Smn‐independent. However, in a muscle with ongoing degeneration (transvs. abdominis), the level of synaptic loss significantly increased, with the percentage of denervated endplates increasing by 33% following injury, compared to disease alone. We therefore conclude that the presence of a die‐back can accelerate synaptic loss after injury in Smn2B/− mice.
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Affiliation(s)
- Alannah J Mole
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Sarah Bell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Alison K Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Kosala N Dissanayake
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Richard R Ribchester
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
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Arbour D, Vande Velde C, Robitaille R. New perspectives on amyotrophic lateral sclerosis: the role of glial cells at the neuromuscular junction. J Physiol 2016; 595:647-661. [PMID: 27633977 DOI: 10.1113/jp270213] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease leading to the death of motor neurons (MNs). It is also recognized as a non-cell autonomous disease where glial cells in the CNS are involved in its pathogenesis and progression. However, although denervation of neuromuscular junctions (NMJs) represents an early and major event in ALS, the importance of glial cells at this synapse receives little attention. An interesting possibility is that altered relationships between glial cells and MNs in the spinal cord in ALS may also take place at the NMJ. Perisynaptic Schwann cells (PSCs), which are glial cells at the NMJ, show great morphological and functional adaptability to ensure NMJ stability, maintenance and repair. More specifically, PSCs change their properties according to the state of innervation. Hence, abnormal changes or lack of changes can have detrimental effects on NMJs in ALS. This review will provide an overview of known and hypothesized interactions between MN nerve terminals and PSCs at NMJs during development, aging and ALS-induced denervation. These neuron-PSC interactions may be crucial to the understanding of how degenerative changes begin and progress at NMJs in ALS, and represent a novel therapeutic target.
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Affiliation(s)
- Danielle Arbour
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7
| | - Christine Vande Velde
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada, H2X 0A9
| | - Richard Robitaille
- Département de neurosciences, Université de Montréal, Montréal, Québec, Canada, H3C 3J7.,Groupe de recherche sur le système nerveux central, Université de Montréal, Montréal, Québec, Canada, H3C 3J7
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Douglas JN, Gardner LA, Salapa HE, Lalor SJ, Lee S, Segal BM, Sawchenko PE, Levin MC. Antibodies to the RNA-binding protein hnRNP A1 contribute to neurodegeneration in a model of central nervous system autoimmune inflammatory disease. J Neuroinflammation 2016; 13:178. [PMID: 27391474 PMCID: PMC4938923 DOI: 10.1186/s12974-016-0647-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/29/2016] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Neurodegeneration is believed to be the primary cause of permanent, long-term disability in patients with multiple sclerosis. The cause of neurodegeneration in multiple sclerosis appears to be multifactorial. One mechanism that has been implicated in the pathogenesis of neurodegeneration in multiple sclerosis is the targeting of neuronal and axonal antigens by autoantibodies. Multiple sclerosis patients develop antibodies to the RNA-binding protein, heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), which is enriched in neurons. We hypothesized that anti-hnRNP A1 antibodies would contribute to neurodegeneration in an animal model of multiple sclerosis. METHODS Following induction of experimental autoimmune encephalomyelitis (EAE) by direct immunization with myelin oligodendrocyte glycoprotein, mice were injected with anti-hnRNP A1 or control antibodies. Animals were examined clinically, and the central nervous system (CNS) tissues were tested for neurodegeneration with Fluoro-Jade C, a marker of degenerating neural elements. RESULTS Injection of anti-hnRNP A1 antibodies in mice with EAE worsened clinical disease, altered the clinical disease phenotype, and caused neurodegeneration preferentially in the ventral spinocerebellar tract and deep white matter of the cerebellum in the CNS. Neurodegeneration in mice injected with hnRNP A1-M9 antibodies compared to control groups was consistent with "dying back" axonal degeneration. CONCLUSIONS These data suggest that antibodies to the RNA-binding protein hnRNP A1 contribute to neurodegeneration in immune-mediated disease of the CNS.
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Affiliation(s)
- Joshua N. Douglas
- />Department of Neurology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 415, Memphis, TN 38163 USA
- />The Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN USA
| | - Lidia A. Gardner
- />Research Service, VA Medical Center, Memphis, TN USA
- />Department of Neurology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 415, Memphis, TN 38163 USA
- />The Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN USA
| | - Hannah E. Salapa
- />Department of Neurology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 415, Memphis, TN 38163 USA
- />The Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN USA
| | - Stephen J. Lalor
- />Department of Neurology, University of Michigan Medical School, Ann Arbor, MI USA
| | - Sangmin Lee
- />Research Service, VA Medical Center, Memphis, TN USA
- />Department of Neurology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 415, Memphis, TN 38163 USA
- />The Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN USA
| | - Benjamin M. Segal
- />Department of Neurology, University of Michigan Medical School, Ann Arbor, MI USA
- />Neurology Service, VA Ann Arbor Health Care System, Ann Arbor, MI USA
| | - Paul E. Sawchenko
- />Laboratory of Neuronal Structure & Function, The Salk Institute, La Jolla, CA USA
| | - Michael C. Levin
- />Research Service, VA Medical Center, Memphis, TN USA
- />Department of Neurology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 415, Memphis, TN 38163 USA
- />The Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN USA
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Expression of EFR3A in the mouse cochlea during degeneration of spiral ganglion following hair cell loss. PLoS One 2015; 10:e0117345. [PMID: 25622037 PMCID: PMC4306511 DOI: 10.1371/journal.pone.0117345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 12/22/2014] [Indexed: 12/26/2022] Open
Abstract
Retrograde degeneration of spiral ganglion cells in the cochlea following hair cell loss is similar to dying back in pathology. The EFR3A gene has recently been discovered to be involved in the pathogenesis of dying back. The relationship of EFR3A and spiral ganglion degeneration, however, was rarely investigated. In this study, we destroyed the hair cells of the mouse cochlea by co-administration of kanamycin and furosemide and then investigated the EFR3A expression during the induced spiral ganglion cell degeneration. Our results revealed that co-administration of kanamycin and furosemide quickly induced hair cell loss in the C57BL/6J mice and then resulted in progressive degeneration of the spiral ganglion beginning at day 5 following drug administration. The number of the spiral ganglion cells began to decrease at day 15. The expression of EFR3A increased remarkably in the spiral ganglion at day 5 and then decreased to near normal level within the next 10 days. Our study suggested that the change of EFR3A expression in the spiral ganglion was coincident with the time of the spiral ganglion degeneration, which implied that high expression of EFR3A may be important to prompt initiation of spiral ganglion degeneration following hair cell loss.
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Sleigh JN, Burgess RW, Gillingwater TH, Cader MZ. Morphological analysis of neuromuscular junction development and degeneration in rodent lumbrical muscles. J Neurosci Methods 2014; 227:159-65. [PMID: 24530702 DOI: 10.1016/j.jneumeth.2014.02.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND The neuromuscular junction (NMJ) is a specialised synapse formed between a lower motor neuron and a skeletal muscle fibre, and is an early pathological target in numerous nervous system disorders, including amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy (SMA). Being able to accurately visualise and quantitatively characterise the NMJ in rodent models of neurological conditions, particularly during the early stages of disease, is thus of clear importance. NEW METHOD We present a method for dissection of rodent deep lumbrical muscles located in the hind-paw, and describe how to perform immunofluorescent morphological analysis of their NMJs. RESULTS These techniques allow the temporal assessment of a number of developmental and pathological NMJ phenotypes in lumbrical muscles. COMPARISON WITH EXISTING METHODS Small muscles, such as the distal hind-limb lumbrical muscles, possess a major advantage over larger muscles, such as gastrocnemius, in that they can be whole-mounted and the entire innervation pattern visualised. This reduces preparation time and ambiguity when evaluating important neuromuscular phenotypes. CONCLUSIONS Together, these methods will allow the reader to perform a detailed and accurate analysis of the neuromuscular system in rodent models of disease in order to identify pertinent features of neuropathology.
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Affiliation(s)
- James N Sleigh
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | | | - Thomas H Gillingwater
- Centre for Integrative Physiology & Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
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Murray L, Gillingwater TH, Kothary R. Dissection of the transversus abdominis muscle for whole-mount neuromuscular junction analysis. J Vis Exp 2014:e51162. [PMID: 24457471 PMCID: PMC4089412 DOI: 10.3791/51162] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Analysis of neuromuscular junction morphology can give important insight into the physiological status of a given motor neuron. Analysis of thin flat muscles can offer significant advantage over traditionally used thicker muscles, such as those from the hind limb (e.g. gastrocnemius). Thin muscles allow for comprehensive overview of the entire innervation pattern for a given muscle, which in turn permits identification of selectively vulnerable pools of motor neurons. These muscles also allow analysis of parameters such as motor unit size, axonal branching, and terminal/nodal sprouting. A common obstacle in using such muscles is gaining the technical expertise to dissect them. In this video, we detail the protocol for dissecting the transversus abdominis (TVA) muscle from young mice and performing immunofluorescence to visualize axons and neuromuscular junctions (NMJs). We demonstrate that this technique gives a complete overview of the innervation pattern of the TVA muscle and can be used to investigate NMJ pathology in a mouse model of the childhood motor neuron disease, spinal muscular atrophy.
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Affiliation(s)
- Lyndsay Murray
- Regenerative Medicine Program, Ottawa Hospital Research Institute
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11
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Axonal degeneration in the peripheral nervous system: Implications for the pathogenesis of amyotrophic lateral sclerosis. Exp Neurol 2013; 246:6-13. [DOI: 10.1016/j.expneurol.2013.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 04/22/2013] [Accepted: 05/02/2013] [Indexed: 12/13/2022]
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12
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Murray LM, Beauvais A, Bhanot K, Kothary R. Defects in neuromuscular junction remodelling in the Smn2B/− mouse model of spinal muscular atrophy. Neurobiol Dis 2013; 49:57-67. [DOI: 10.1016/j.nbd.2012.08.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 08/17/2012] [Accepted: 08/22/2012] [Indexed: 10/28/2022] Open
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Kanamori A, Catrinescu MM, Belisle JM, Costantino S, Levin LA. Retrograde and Wallerian axonal degeneration occur synchronously after retinal ganglion cell axotomy. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:62-73. [PMID: 22642911 DOI: 10.1016/j.ajpath.2012.03.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 03/05/2012] [Accepted: 03/15/2012] [Indexed: 01/23/2023]
Abstract
Axonal injury and degeneration are pivotal pathological events in diseases of the nervous system. In the past decade, it has been recognized that the process of axonal degeneration is distinct from somal degeneration and that axoprotective strategies may be distinct from those that protect the soma. Preserving the cell body via neuroprotection cannot improve function if the axon is damaged, because the soma is still disconnected from its target. Therefore, understanding the mechanisms of axonal degeneration is critical for developing new therapeutic interventions for axonal disease treatment. We combined in vivo imaging with a multilaser confocal scanning laser ophthalmoscope and in vivo axotomy with a diode-pumped solid-state laser to assess the time course of Wallerian and retrograde degeneration of unmyelinated retinal ganglion cell axons in living rats for 4 weeks after intraretinal axotomy. Laser injury resulted in reproducible axon loss both distal and proximal to the site of injury. Longitudinal polarization-sensitive imaging of axons demonstrated that Wallerian and retrograde degeneration occurred synchronously. Neurofilament immunostaining of retinal whole-mounts confirmed axonal loss and demonstrated sparing of adjacent axons to the axotomy site. In vivo fluorescent imaging of axonal transport and photobleaching of labeled axons demonstrated that the laser axotomy model did not affect adjacent axon function. These results are consistent with a shared mechanism for Wallerian and retrograde degeneration.
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Affiliation(s)
- Akiyasu Kanamori
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Quebec, Canada
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Tamboli RA, Hajri T, Jiang A, Marks-Shulman PA, Williams DB, Clements RH, Melvin W, Bowen BP, Shyr Y, Abumrad NN, Flynn CR. Reduction in inflammatory gene expression in skeletal muscle from Roux-en-Y gastric bypass patients randomized to omentectomy. PLoS One 2011; 6:e28577. [PMID: 22194858 PMCID: PMC3241684 DOI: 10.1371/journal.pone.0028577] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Accepted: 11/10/2011] [Indexed: 12/19/2022] Open
Abstract
Objectives To examine the effects of Roux-en-Y gastric bypass (RYGB) surgery with and without laparoscopic removal of omental fat (omentectomy) on the temporal gene expression profiles of skeletal muscle. Design Previously reported were the whole-body metabolic effects of a randomized, single-blinded study in patients receiving RYGB surgery stratified to receive or not receive omentectomy. In this follow up study we report on changes in skeletal muscle gene expression in a subset of 21 patients, for whom biopsies were collected preoperatively and at either 6 months or 12 months postoperatively. Methodology/Principal Findings RNA isolated from skeletal muscle biopsies of 21 subjects (8 without omentectomy and 13 with omentectomy) taken before RYGB or at 6 and 12 months postoperatively were subjected to gene expression profiling via Exon 1.0 S/T Array and Taqman Low Density Array. Robust Multichip Analysis and gene enrichment data analysis revealed 84 genes with at least a 4-fold expression difference after surgery. At 6 and 12 months the RYGB with omentectomy group displayed a greater reduction in the expression of genes associated with skeletal muscle inflammation (ANKRD1, CDR1, CH25H, CXCL2, CX3CR1, IL8, LBP, NFIL3, SELE, SOCS3, TNFAIP3, and ZFP36) relative to the RYGB non-omentectomy group. Expressions of IL6 and CCL2 were decreased at all postoperative time points. There was differential expression of genes driving protein turnover (IGFN1, FBXW10) in both groups over time and increased expression of PAAF1 in the non-omentectomy group at 12 months. Evidence for the activation of skeletal muscle satellite cells was inferred from the up-regulation of HOXC10. The elevated post-operative expression of 22 small nucleolar RNAs and the decreased expression of the transcription factors JUNB, FOS, FOSB, ATF3 MYC, EGR1 as well as the orphan nuclear receptors NR4A1, NR4A2, NR4A3 suggest dramatic reorganizations at both the cellular and genetic levels. Conclusions/Significance These data indicate that RYGB reduces skeletal muscle inflammation, and removal of omental fat further amplifies this response. Trial Registration ClinicalTrials.gov NCT00212160
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Affiliation(s)
- Robyn A. Tamboli
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Tahar Hajri
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Aixiang Jiang
- Department of Cancer Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Pamela A. Marks-Shulman
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - D. Brandon Williams
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Ronald H. Clements
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Willie Melvin
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Benjamin P. Bowen
- Department of GTL Bioenergy and Structural Biology, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Yu Shyr
- Department of Cancer Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Naji N. Abumrad
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Charles Robb Flynn
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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15
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Comley LH, Fuller HR, Wishart TM, Mutsaers CA, Thomson D, Wright AK, Ribchester RR, Morris GE, Parson SH, Horsburgh K, Gillingwater TH. ApoE isoform-specific regulation of regeneration in the peripheral nervous system. Hum Mol Genet 2011; 20:2406-21. [PMID: 21478199 DOI: 10.1093/hmg/ddr147] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Apolipoprotein E (apoE) is a 34 kDa glycoprotein with three distinct isoforms in the human population (apoE2, apoE3 and apoE4) known to play a major role in differentially influencing risk to, as well as outcome from, disease and injury in the central nervous system. In general, the apoE4 allele is associated with poorer outcomes after disease or injury, whereas apoE3 is associated with better responses. The extent to which different apoE isoforms influence degenerative and regenerative events in the peripheral nervous system (PNS) is still to be established, and the mechanisms through which apoE exerts its isoform-specific effects remain unclear. Here, we have investigated isoform-specific effects of human apoE on the mouse PNS. Experiments in mice ubiquitously expressing human apoE3 or human apoE4 on a null mouse apoE background revealed that apoE4 expression significantly disrupted peripheral nerve regeneration and subsequent neuromuscular junction re-innervation following nerve injury compared with apoE3, with no observable effects on normal development, maturation or Wallerian degeneration. Proteomic isobaric tag for relative and absolute quantitation (iTRAQ) screens comparing healthy and regenerating peripheral nerves from mice expressing apoE3 or apoE4 revealed significant differences in networks of proteins regulating cellular outgrowth and regeneration (myosin/actin proteins), as well as differences in expression levels of proteins involved in regulating the blood-nerve barrier (including orosomucoid 1). Taken together, these findings have identified isoform-specific roles for apoE in determining the protein composition of peripheral nerve as well as regulating nerve regeneration pathways in vivo.
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Affiliation(s)
- Laura H Comley
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
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16
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Comley LH, Wishart TM, Baxter B, Murray LM, Nimmo A, Thomson D, Parson SH, Gillingwater TH. Induction of cell stress in neurons from transgenic mice expressing yellow fluorescent protein: implications for neurodegeneration research. PLoS One 2011; 6:e17639. [PMID: 21408118 PMCID: PMC3050905 DOI: 10.1371/journal.pone.0017639] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 02/04/2011] [Indexed: 11/30/2022] Open
Abstract
Background Mice expressing fluorescent proteins in neurons are one of the most powerful tools in modern neuroscience research and are increasingly being used for in vivo studies of neurodegeneration. However, these mice are often used under the assumption that the fluorescent proteins present are biologically inert. Methodology/Principal Findings Here, we show that thy1-driven expression of yellow fluorescent protein (YFP) in neurons triggers multiple cell stress responses at both the mRNA and protein levels in vivo. The presence of YFP in neurons also subtly altered neuronal morphology and modified the time-course of dying-back neurodegeneration in experimental axonopathy, but not in Wallerian degeneration triggered by nerve injury. Conclusions/Significance We conclude that fluorescent protein expressed in thy1-YFP mice is not biologically inert, modifies molecular and cellular characteristics of neurons in vivo, and has diverse and unpredictable effects on neurodegeneration pathways.
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Affiliation(s)
- Laura H. Comley
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Becki Baxter
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Ailish Nimmo
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Derek Thomson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- * E-mail:
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17
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Murray LM, Comley LH, Gillingwater TH, Parson SH. The response of neuromuscular junctions to injury is developmentally regulated. FASEB J 2011; 25:1306-13. [DOI: 10.1096/fj.10-171934] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Laura H. Comley
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
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18
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Wright AK, Wishart TM, Ingham CA, Gillingwater TH. Synaptic protection in the brain of WldS mice occurs independently of age but is sensitive to gene-dose. PLoS One 2010; 5:e15108. [PMID: 21124744 PMCID: PMC2993971 DOI: 10.1371/journal.pone.0015108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/21/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Disruption of synaptic connectivity is a significant early event in many neurodegenerative conditions affecting the aging CNS, including Alzheimer's disease and Parkinson's disease. Therapeutic approaches that protect synapses from degeneration in the aging brain offer the potential to slow or halt the progression of such conditions. A range of animal models expressing the slow Wallerian Degeneration (Wld(S)) gene show robust neuroprotection of synapses and axons from a wide variety of traumatic and genetic neurodegenerative stimuli in both the central and peripheral nervous systems, raising that possibility that Wld(S) may be useful as a neuroprotective agent in diseases with synaptic pathology. However, previous studies of neuromuscular junctions revealed significant negative effects of increasing age and positive effects of gene-dose on Wld(S)-mediated synaptic protection in the peripheral nervous system, raising doubts as to whether Wld(S) is capable of directly conferring synapse protection in the aging brain. METHODOLOGY/PRINCIPAL FINDINGS We examined the influence of age and gene-dose on synaptic protection in the brain of mice expressing the Wld(S) gene using an established cortical lesion model to induce synaptic degeneration in the striatum. Synaptic protection was found to be sensitive to Wld(S) gene-dose, with heterozygous Wld(S) mice showing approximately half the level of protection observed in homozygous Wld(S) mice. Increasing age had no influence on levels of synaptic protection. In contrast to previous findings in the periphery, synapses in the brain of old Wld(S) mice were just as strongly protected as those in young mice. CONCLUSIONS/SIGNIFICANCE Our study demonstrates that Wld(S)-mediated synaptic protection in the CNS occurs independently of age, but is sensitive to gene dose. This suggests that the Wld(S) gene, and in particular its downstream endogenous effector pathways, may be potentially useful therapeutic agents for conferring synaptic protection in the aging brain.
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Affiliation(s)
- Ann K. Wright
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Cali A. Ingham
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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19
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Murray L, Gillingwater T, Parson S. Using mouse cranial muscles to investigate neuromuscular pathology in vivo. Neuromuscul Disord 2010; 20:740-3. [DOI: 10.1016/j.nmd.2010.06.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 05/26/2010] [Accepted: 06/21/2010] [Indexed: 02/09/2023]
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20
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Wishart TM, Huang JPW, Murray LM, Lamont DJ, Mutsaers CA, Ross J, Geldsetzer P, Ansorge O, Talbot K, Parson SH, Gillingwater TH. SMN deficiency disrupts brain development in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2010; 19:4216-28. [PMID: 20705736 DOI: 10.1093/hmg/ddq340] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Reduced expression of the survival motor neuron (SMN) gene causes the childhood motor neuron disease spinal muscular atrophy (SMA). Low levels of ubiquitously expressed SMN protein result in the degeneration of lower motor neurons, but it remains unclear whether other regions of the nervous system are also affected. Here we show that reduced levels of SMN lead to impaired perinatal brain development in a mouse model of severe SMA. Regionally selective changes in brain morphology were apparent in areas normally associated with higher SMN levels in the healthy postnatal brain, including the hippocampus, and were associated with decreased cell density, reduced cell proliferation and impaired hippocampal neurogenesis. A comparative proteomics analysis of the hippocampus from SMA and wild-type littermate mice revealed widespread modifications in expression levels of proteins regulating cellular proliferation, migration and development when SMN levels were reduced. This study reveals novel roles for SMN protein in brain development and maintenance and provides the first insights into cellular and molecular pathways disrupted in the brain in a severe form of SMA.
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Affiliation(s)
- Thomas M Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Medical School, Edinburgh, UK
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21
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Mapping of fluorescent protein-expressing neurons and axon pathways in adult and developing Thy1-eYFP-H transgenic mice. Brain Res 2010; 1345:59-72. [DOI: 10.1016/j.brainres.2010.05.061] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/19/2010] [Accepted: 05/19/2010] [Indexed: 11/21/2022]
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22
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Murray LM, Talbot K, Gillingwater TH. Review: Neuromuscular synaptic vulnerability in motor neurone disease: amyotrophic lateral sclerosis and spinal muscular atrophy. Neuropathol Appl Neurobiol 2010; 36:133-56. [DOI: 10.1111/j.1365-2990.2010.01061.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Bäumer D, Lee S, Nicholson G, Davies JL, Parkinson NJ, Murray LM, Gillingwater TH, Ansorge O, Davies KE, Talbot K. Alternative splicing events are a late feature of pathology in a mouse model of spinal muscular atrophy. PLoS Genet 2009; 5:e1000773. [PMID: 20019802 PMCID: PMC2787017 DOI: 10.1371/journal.pgen.1000773] [Citation(s) in RCA: 185] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 11/16/2009] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy is a severe motor neuron disease caused by inactivating mutations in the SMN1 gene leading to reduced levels of full-length functional SMN protein. SMN is a critical mediator of spliceosomal protein assembly, and complete loss or drastic reduction in protein leads to loss of cell viability. However, the reason for selective motor neuron degeneration when SMN is reduced to levels which are tolerated by all other cell types is not currently understood. Widespread splicing abnormalities have recently been reported at end-stage in a mouse model of SMA, leading to the proposition that disruption of efficient splicing is the primary mechanism of motor neuron death. However, it remains unclear whether splicing abnormalities are present during early stages of the disease, which would be a requirement for a direct role in disease pathogenesis. We performed exon-array analysis of RNA from SMN deficient mouse spinal cord at 3 time points, pre-symptomatic (P1), early symptomatic (P7), and late-symptomatic (P13). Compared to littermate control mice, SMA mice showed a time-dependent increase in the number of exons showing differential expression, with minimal differences between genotypes at P1 and P7, but substantial variation in late-symptomatic (P13) mice. Gene ontology analysis revealed differences in pathways associated with neuronal development as well as cellular injury. Validation of selected targets by RT-PCR confirmed the array findings and was in keeping with a shift between physiologically occurring mRNA isoforms. We conclude that the majority of splicing changes occur late in SMA and may represent a secondary effect of cell injury, though we cannot rule out significant early changes in a small number of transcripts crucial to motor neuron survival.
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Affiliation(s)
- Dirk Bäumer
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Sheena Lee
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Joanna L. Davies
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. Parkinson
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lyndsay M. Murray
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, United Kingdom
| | - Thomas H. Gillingwater
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, United Kingdom
| | - Olaf Ansorge
- Department of Neuropathology, John Radcliffe Hospital, Oxford, United Kingdom
| | - Kay E. Davies
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Kevin Talbot
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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24
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Murray LM, Lee S, Bäumer D, Parson SH, Talbot K, Gillingwater TH. Pre-symptomatic development of lower motor neuron connectivity in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2009; 19:420-33. [PMID: 19884170 DOI: 10.1093/hmg/ddp506] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The childhood motor neuron disease spinal muscular atrophy (SMA) results from reduced expression of the survival motor neuron (SMN) gene. Previous studies using in vitro model systems and lower organisms have suggested that low levels of Smn protein disrupt prenatal developmental processes in lower motor neurons, influencing neuronal outgrowth, axon branching and neuromuscular connectivity. The extent to which these developmental pathways contribute to selective vulnerability and pathology in the mammalian neuromuscular system in vivo remains unclear. Here, we have investigated the pre-symptomatic development of neuromuscular connectivity in differentially vulnerable motor neuron populations in Smn(-/-);SMN2 mice, a model of severe SMA. We show that reduced Smn levels have no detectable effect on morphological correlates of pre-symptomatic development in either vulnerable or stable motor units, indicating that abnormal pre-symptomatic developmental processes are unlikely to be a prerequisite for subsequent pathological changes to occur in vivo. Microarray analyses of spinal cord from two different severe SMA mouse models demonstrated that only minimal changes in gene expression were present in pre-symptomatic mice. In stark contrast, microarray analysis of late-symptomatic spinal cord revealed widespread changes in gene expression, implicating extracellular matrix integrity, growth factor signalling and myelination pathways in SMA pathogenesis. Taken together, these data suggest that reduced Smn levels induce SMA pathology by instigating rapidly progressive neurodegenerative pathways in lower motor neurons around the time of disease onset rather than by modulating pre-symptomatic neurodevelopmental pathways.
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Affiliation(s)
- Lyndsay M Murray
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, UK
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25
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Kielar C, Wishart TM, Palmer A, Dihanich S, Wong AM, Macauley SL, Chan CH, Sands MS, Pearce DA, Cooper JD, Gillingwater TH. Molecular correlates of axonal and synaptic pathology in mouse models of Batten disease. Hum Mol Genet 2009; 18:4066-80. [PMID: 19640925 PMCID: PMC2758138 DOI: 10.1093/hmg/ddp355] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Neuronal ceroid lipofuscinoses (NCLs; Batten disease) are collectively the most frequent autosomal-recessive neurodegenerative disease of childhood, but the underlying cellular and molecular mechanisms remain unclear. Several lines of evidence have highlighted the important role that non-somatic compartments of neurons (axons and synapses) play in the instigation and progression of NCL pathogenesis. Here, we report a progressive breakdown of axons and synapses in the brains of two different mouse models of NCL: Ppt1−/− model of infantile NCL and Cln6nclf model of variant late-infantile NCL. Synaptic pathology was evident in the thalamus and cortex of these mice, but occurred much earlier within the thalamus. Quantitative comparisons of expression levels for a subset of proteins previously implicated in regulation of axonal and synaptic vulnerability revealed changes in proteins involved with synaptic function/stability and cell-cycle regulation in both strains of NCL mice. Protein expression changes were present at pre/early-symptomatic stages, occurring in advance of morphologically detectable synaptic or axonal pathology and again displayed regional selectivity, occurring first within the thalamus and only later in the cortex. Although significant differences in individual protein expression profiles existed between the two NCL models studied, 2 of the 15 proteins examined (VDAC1 and Pttg1) displayed robust and significant changes at pre/early-symptomatic time-points in both models. Our study demonstrates that synapses and axons are important early pathological targets in the NCLs and has identified two proteins, VDAC1 and Pttg1, with the potential for use as in vivo biomarkers of pre/early-symptomatic axonal and synaptic vulnerability in the NCLs.
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Affiliation(s)
- Catherine Kielar
- Department of Neuroscience, Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, London SE5 9NU, UK
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Li LH, Qin HZ, Wang JL, Wang J, Wang XL, Gao GD. Axonal degeneration of nigra-striatum dopaminergic neurons induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in mice. J Int Med Res 2009; 37:455-63. [PMID: 19383240 DOI: 10.1177/147323000903700221] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
As one of the main pathological changes of Parkinson's disease (PD), axonal degeneration was thought to be a passive process that is secondary to the apoptosis of dopaminergic neurons and, therefore, it has been overlooked for some time. Recent research, however, has indicated that axonal injury is the first location of damage in dopaminergic neurons in PD, and that the degree of injury in axonal degeneration is higher than in neural death. This study explored the relationship between apoptosis of dopaminergic neurons and their axonal degeneration by observing dopaminergic neuronal injury and axonal degeneration in the substantia nigra-striatum in different animal PD model and control groups. The results show that axonal degeneration plays a crucial role in the pathogenesis of PD and suggest that the process of axonal degeneration occurs independently of apoptosis and may even induce neuronal apoptosis. Thus, preventing axonal degeneration may be a potential new therapeutic strategy for PD.
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Affiliation(s)
- L-H Li
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an City, China
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