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Kumar V, Sami N, Kashav T, Islam A, Ahmad F, Hassan MI. Protein aggregation and neurodegenerative diseases: From theory to therapy. Eur J Med Chem 2016; 124:1105-1120. [DOI: 10.1016/j.ejmech.2016.07.054] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 12/23/2022]
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202
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Monitoring peripheral nerve degeneration in ALS by label-free stimulated Raman scattering imaging. Nat Commun 2016; 7:13283. [PMID: 27796305 PMCID: PMC5095598 DOI: 10.1038/ncomms13283] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 09/19/2016] [Indexed: 01/02/2023] Open
Abstract
The study of amyotrophic lateral sclerosis (ALS) and potential interventions would be facilitated if motor axon degeneration could be more readily visualized. Here we demonstrate that stimulated Raman scattering (SRS) microscopy could be used to sensitively monitor peripheral nerve degeneration in ALS mouse models and ALS autopsy materials. Three-dimensional imaging of pre-symptomatic SOD1 mouse models and data processing by a correlation-based algorithm revealed that significant degeneration of peripheral nerves could be detected coincidentally with the earliest detectable signs of muscle denervation and preceded physiologically measurable motor function decline. We also found that peripheral degeneration was an early event in FUS as well as C9ORF72 repeat expansion models of ALS, and that serial imaging allowed long-term observation of disease progression and drug effects in living animals. Our study demonstrates that SRS imaging is a sensitive and quantitative means of measuring disease progression, greatly facilitating future studies of disease mechanisms and candidate therapeutics.
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203
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Misawa H, Inomata D, Kikuchi M, Maruyama S, Moriwaki Y, Okuda T, Nukina N, Yamanaka T. Reappraisal of VAChT-Cre: Preference in slow motor neurons innervating type I or IIa muscle fibers. Genesis 2016; 54:568-572. [PMID: 27596971 DOI: 10.1002/dvg.22979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/26/2022]
Abstract
VAChT-Cre.Fast and VAChT-Cre.Slow mice selectively express Cre recombinase in approximately one half of postnatal somatic motor neurons. The mouse lines have been used in various studies with selective genetic modifications in adult motor neurons. In the present study, we crossed VAChT-Cre lines with a reporter line, CAG-Syp/tdTomato, in which synaptophysin-tdTomato fusion proteins are efficiently sorted to axon terminals, making it possible to label both cell bodies and axon terminals of motor neurons. In the mice, Syp/tdTomato fluorescence preferentially co-localized with osteopontin, a recently discovered motor neuron marker for slow-twitch fatigue-resistant (S) and fast-twitch fatigue-resistant (FR) types. The fluorescence did not preferentially co-localize with matrix metalloproteinase-9, a marker for fast-twitch fatigable (FF) motor neurons. In the neuromuscular junctions, Syp/tdTomato fluorescence was detected mainly in motor nerve terminals that innervate type I or IIa muscle fibers. These results suggest that the VAChT-Cre lines are Cre-drivers that have selectivity in S and FR motor neurons. In order to avoid confusion, we have changed the mouse line names from VAChT-Cre.Fast and VAChT-Cre.Slow to VAChT-Cre.Early and VAChT-Cre.Late, respectively. The mouse lines will be useful tools to study slow-type motor neurons, in relation to physiology and pathology.
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Affiliation(s)
- Hidemi Misawa
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Daijiro Inomata
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Miseri Kikuchi
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Sae Maruyama
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Yasuhiro Moriwaki
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Takashi Okuda
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan
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204
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Jeong C, Yoo J, Lee D, Kim YC. A branched TAT cell-penetrating peptide as a novel delivery carrier for the efficient gene transfection. Biomater Res 2016; 20:28. [PMID: 27606074 PMCID: PMC5013572 DOI: 10.1186/s40824-016-0076-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/18/2016] [Indexed: 01/08/2023] Open
Abstract
Background Cell penetrating peptides (CPPs) as one class of non-viral vectors, have been widely explored as a delivery tool due to their cell-penetrating capability with low cytotoxicity. However, CPPs have reported to have low gene transfection efficiency mainly due to the fact that DNA is larger than other biomolecules. On the other hand, the conventional linear CPPs are unstable for constructing the DNA complexes with it. Thus, here we designed a branched CPP using disulfide bridges based on the linear TAT peptide, to enhance the gene delivery efficiency in a better way. Results The branched TAT (BTAT) was synthesized by the DMSO oxidation method and showed high-molecular-weight about 294 kDa. The resulting BTAT was complexed with plasmid green fluorescence protein (pGFP) gene at various N/P ratios. The gene transfection efficiency was assessed on HeLa cells after treating with BTAT/pGFP complexes, showed high gene transfection efficiency as conformed by flowcytometry followed by confocal laser scanning microscopy (CLSM) visualization. Conclusion The novel BTAT/pGFP complex exhibited significantly higher stability and redox cleavability by reducing agent. In addition, BTAT showed higher transfection efficiency approximately 40-fold than those of the TAT and mTAT complexes. Our primary experiments demonstrated the potential of BTAT as a suitable candidate for gene delivery and it could be applied for various types of gene delivery platforms.
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Affiliation(s)
- Chanuk Jeong
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 Republic of Korea
| | - Jisang Yoo
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 Republic of Korea
| | - DaeYong Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 Republic of Korea
| | - Yeu-Chun Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 Republic of Korea
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205
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Sakakibara I, Wurmser M, Dos Santos M, Santolini M, Ducommun S, Davaze R, Guernec A, Sakamoto K, Maire P. Six1 homeoprotein drives myofiber type IIA specialization in soleus muscle. Skelet Muscle 2016; 6:30. [PMID: 27597886 PMCID: PMC5011358 DOI: 10.1186/s13395-016-0102-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/16/2016] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Adult skeletal muscles are composed of slow and fast myofiber subtypes which each express selective genes required for their specific contractile and metabolic activity. Six homeoproteins are transcription factors regulating muscle cell fate through activation of myogenic regulatory factors and driving fast-type gene expression during embryogenesis. RESULTS We show here that Six1 protein accumulates more robustly in the nuclei of adult fast-type muscles than in adult slow-type muscles, this specific enrichment takes place during perinatal growth. Deletion of Six1 in soleus impaired fast-type myofiber specialization during perinatal development, resulting in a slow phenotype and a complete lack of Myosin heavy chain 2A (MyHCIIA) expression. Global transcriptomic analysis of wild-type and Six1 mutant myofibers identified the gene networks controlled by Six1 in adult soleus muscle. This analysis showed that Six1 is required for the expression of numerous genes encoding fast-type sarcomeric proteins, glycolytic enzymes and controlling intracellular calcium homeostasis. Parvalbumin, a key player of calcium buffering, in particular, is a direct target of Six1 in the adult myofiber. CONCLUSIONS This analysis revealed that Six1 controls distinct aspects of adult muscle physiology in vivo, and acts as a main determinant of fast-fiber type acquisition and maintenance.
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Affiliation(s)
- Iori Sakakibara
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
- Division of Integrative Pathophysiology, Proteo-Science Center, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - Maud Wurmser
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Matthieu Dos Santos
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Marc Santolini
- Laboratoire de Physique Statistique, CNRS, Université P. et M. Curie, Université D. Diderot, École Normale Supérieure, Paris, 75005 France
| | - Serge Ducommun
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Romain Davaze
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Anthony Guernec
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Pascal Maire
- INSERM U1016, Institut Cochin, Paris, 75014 France
- CNRS UMR 8104, Paris, 75014 France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, 75014 France
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206
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Modeling ALS with motor neurons derived from human induced pluripotent stem cells. Nat Neurosci 2016; 19:542-53. [PMID: 27021939 DOI: 10.1038/nn.4273] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 02/22/2016] [Indexed: 02/08/2023]
Abstract
Directing the differentiation of induced pluripotent stem cells into motor neurons has allowed investigators to develop new models of amyotrophic lateral sclerosis (ALS). However, techniques vary between laboratories and the cells do not appear to mature into fully functional adult motor neurons. Here we discuss common developmental principles of both lower and upper motor neuron development that have led to specific derivation techniques. We then suggest how these motor neurons may be matured further either through direct expression or administration of specific factors or coculture approaches with other tissues. Ultimately, through a greater understanding of motor neuron biology, it will be possible to establish more reliable models of ALS. These in turn will have a greater chance of validating new drugs that may be effective for the disease.
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207
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Miller N, Shi H, Zelikovich AS, Ma YC. Motor neuron mitochondrial dysfunction in spinal muscular atrophy. Hum Mol Genet 2016; 25:3395-3406. [PMID: 27488123 DOI: 10.1093/hmg/ddw262] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, predominantly affects high metabolic tissues including motor neurons, skeletal muscles and the heart. Although the genetic cause of SMA has been identified, mechanisms underlying tissue-specific vulnerability are not well understood. To study these mechanisms, we carried out a deep sequencing analysis of the transcriptome of spinal motor neurons in an SMA mouse model, in which we unexpectedly found changes in many genes associated with mitochondrial bioenergetics. Importantly, functional measurement of mitochondrial activities showed decreased basal and maximal mitochondrial respiration in motor neurons from SMA mice. Using a reduction-oxidation sensitive GFP and fluorescence sensors specifically targeted to mitochondria, we found increased oxidative stress level and impaired mitochondrial membrane potential in motor neurons affected by SMA. In addition, mitochondrial mobility was impaired in SMA disease conditions, with decreased retrograde transport but no effect on anterograde transport. We also found significantly increased fragmentation of the mitochondrial network in primary motor neurons from SMA mice, with no change in mitochondria density. Electron microscopy study of SMA mouse spinal cord revealed mitochondria fragmentation, edema and concentric lamellar inclusions in motor neurons affected by the disease. Intriguingly, these functional and structural deficiencies in the SMA mouse model occur during the presymptomatic stage of disease, suggesting a role in initiating SMA. Altogether, our findings reveal a critical role for mitochondrial defects in SMA pathogenesis and suggest a novel target for improving tissue health in the disease.
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Affiliation(s)
- Nimrod Miller
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Han Shi
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Aaron S Zelikovich
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Yong-Chao Ma
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
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208
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Lenschow C, Cazalets JR, Bertrand SS. Distinct and developmentally regulated activity-dependent plasticity at descending glutamatergic synapses on flexor and extensor motoneurons. Sci Rep 2016; 6:28522. [PMID: 27329279 PMCID: PMC4916427 DOI: 10.1038/srep28522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/02/2016] [Indexed: 11/09/2022] Open
Abstract
Activity-dependent synaptic plasticity (ADSP) is paramount to synaptic processing and maturation. However, identifying the ADSP capabilities of the numerous synapses converging onto spinal motoneurons (MNs) remain elusive. Using spinal cord slices from mice at two developmental stages, 1–4 and 8–12 postnatal days (P1–P4; P8–P12), we found that high-frequency stimulation of presumed reticulospinal neuron axons in the ventrolateral funiculus (VLF) induced either an NMDA receptor-dependent-long-term depression (LTD), a short-term depression (STD) or no synaptic modulation in limb MNs. Our study shows that P1–P4 cervical MNs expressed the same plasticity profiles as P8–P12 lumbar MNs rather than P1–P4 lumbar MNs indicating that ADSP expression at VLF-MN synapses is linked to the rostrocaudal development of spinal motor circuitry. Interestingly, we observed that the ADSP expressed at VLF-MN was related to the functional flexor or extensor MN subtype. Moreover, heterosynaptic plasticity was triggered in MNs by VLF axon tetanisation at neighbouring synapses not directly involved in the plasticity induction. ADSP at VLF-MN synapses specify differential integrative synaptic processing by flexor and extensor MNs and could contribute to the maturation of spinal motor circuits and developmental acquisition of weight-bearing locomotion.
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209
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Morisaki Y, Niikura M, Watanabe M, Onishi K, Tanabe S, Moriwaki Y, Okuda T, Ohara S, Murayama S, Takao M, Uchida S, Yamanaka K, Misawa H. Selective Expression of Osteopontin in ALS-resistant Motor Neurons is a Critical Determinant of Late Phase Neurodegeneration Mediated by Matrix Metalloproteinase-9. Sci Rep 2016; 6:27354. [PMID: 27264390 PMCID: PMC4893611 DOI: 10.1038/srep27354] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 05/17/2016] [Indexed: 12/13/2022] Open
Abstract
Differential vulnerability among motor neuron (MN) subtypes is a fundamental feature of amyotrophic lateral sclerosis (ALS): fast-fatigable (FF) MNs are more vulnerable than fast fatigue-resistant (FR) or slow (S) MNs. The reason for this selective vulnerability remains enigmatic. We report here that the extracellular matrix (ECM) protein osteopontin (OPN) is selectively expressed by FR and S MNs and ALS-resistant motor pools, whereas matrix metalloproteinase-9 (MMP-9) is selectively expressed by FF MNs. OPN is secreted and accumulated as extracellular granules in ECM in three ALS mouse models and a human ALS patient. In SOD1(G93A) mice, OPN/MMP-9 double positivity marks remodeled FR and S MNs destined to compensate for lost FF MNs before ultimately dying. Genetic ablation of OPN in SOD1(G93A) mice delayed disease onset but then accelerated disease progression. OPN induced MMP-9 up-regulation via αvβ3 integrin in ChAT-expressing Neuro2a cells, and also induced CD44-mediated astrocyte migration and microglial phagocytosis in a non-cell-autonomous manner. Our results demonstrate that OPN expressed by FR/S MNs is involved in the second-wave neurodegeneration by up-regulating MMP-9 through αvβ3 integrin in the mouse model of ALS. The differences in OPN/MMP-9 expression profiles in MN subsets partially explain the selective MN vulnerability in ALS.
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Affiliation(s)
- Yuta Morisaki
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Mamiko Niikura
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Mizuho Watanabe
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Kosuke Onishi
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Shogo Tanabe
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Yasuhiro Moriwaki
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Takashi Okuda
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
| | - Shinji Ohara
- Department of Neurology, Matsumoto Medical Center, Chushin-Matsumoto Hospital, Matsumoto 399-0021, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
| | - Masaki Takao
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
| | - Sae Uchida
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
| | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Hidemi Misawa
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo 105-8512, Japan
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210
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Scekic-Zahirovic J, Sendscheid O, El Oussini H, Jambeau M, Sun Y, Mersmann S, Wagner M, Dieterlé S, Sinniger J, Dirrig-Grosch S, Drenner K, Birling MC, Qiu J, Zhou Y, Li H, Fu XD, Rouaux C, Shelkovnikova T, Witting A, Ludolph AC, Kiefer F, Storkebaum E, Lagier-Tourenne C, Dupuis L. Toxic gain of function from mutant FUS protein is crucial to trigger cell autonomous motor neuron loss. EMBO J 2016; 35:1077-97. [PMID: 26951610 PMCID: PMC4868956 DOI: 10.15252/embj.201592559] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022] Open
Abstract
FUS is an RNA-binding protein involved in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS-containing aggregates are often associated with concomitant loss of nuclear FUS Whether loss of nuclear FUS function, gain of a cytoplasmic function, or a combination of both lead to neurodegeneration remains elusive. To address this question, we generated knockin mice expressing mislocalized cytoplasmic FUS and complete FUS knockout mice. Both mouse models display similar perinatal lethality with respiratory insufficiency, reduced body weight and length, and largely similar alterations in gene expression and mRNA splicing patterns, indicating that mislocalized FUS results in loss of its normal function. However, FUS knockin mice, but not FUS knockout mice, display reduced motor neuron numbers at birth, associated with enhanced motor neuron apoptosis, which can be rescued by cell-specific CRE-mediated expression of wild-type FUS within motor neurons. Together, our findings indicate that cytoplasmic FUS mislocalization not only leads to nuclear loss of function, but also triggers motor neuron death through a toxic gain of function within motor neurons.
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Affiliation(s)
- Jelena Scekic-Zahirovic
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Oliver Sendscheid
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Hajer El Oussini
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Mélanie Jambeau
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Ying Sun
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Sina Mersmann
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Marina Wagner
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Stéphane Dieterlé
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Jérome Sinniger
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Sylvie Dirrig-Grosch
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Kevin Drenner
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | | | - Jinsong Qiu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Yu Zhou
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Hairi Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Caroline Rouaux
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | | | - Anke Witting
- Department of Neurology University of Ulm, Ulm, Germany
| | | | - Friedemann Kiefer
- Mammalian Cell Signaling Laboratory, Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Erik Storkebaum
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Clotilde Lagier-Tourenne
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Luc Dupuis
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
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211
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Solanki I, Parihar P, Parihar MS. Neurodegenerative diseases: From available treatments to prospective herbal therapy. Neurochem Int 2016; 95:100-8. [PMID: 26550708 DOI: 10.1016/j.neuint.2015.11.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/23/2015] [Accepted: 11/03/2015] [Indexed: 11/23/2022]
Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and many others represent a relevant health problem with age worldwide. Efforts have been made in recent years to discover the mechanism of neurodegenerative diseases and prospective therapy that can help to slow down the effects of the aging and prevent these diseases. Since pathogenesis of these diseases involves multiple factors therefore the important task for neuroscientists is to identify such multiple factors and prevent age-associated neurodegenerative diseases. For these neurodegenerative diseases yet we have only palliative therapies and none of them significantly capable to slow down or halt the underlying pathology. Polyphenolic compounds such as flavonoids present in vegetables and fruits are believed to have anti-aging properties and reduce the risk of neurodegenerative diseases. Despite their abundance, investigations into the benefits of these polyphenolic compounds in human health have only recently begun. Preclinical and clinical studies have demonstrated the potential beneficial effects of flavonoids in neurons. Although clinical trials on the effectiveness of dietary flavonoids to treat human diseases are limited but various animal models and cell culture studies have shown a great promise in developing these compounds as suitable therapeutic targets. In this review, we elaborate the neuroprotective properties of flavonoids especially their applications in prevention and intervention of different neurodegenerative diseases. Their multi-target properties may allow them to be potential dietary supplement in prevention and treatment of the age-associated neurodegenerative diseases.
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Affiliation(s)
- Isha Solanki
- School of Studies in Zoology & Biotechnology, Vikram University, Ujjain, MP, India
| | - Priyanka Parihar
- School of Studies in Zoology & Biotechnology, Vikram University, Ujjain, MP, India
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Tung YT, Lu YL, Peng KC, Yen YP, Chang M, Li J, Jung H, Thams S, Huang YP, Hung JH, Chen JA. Mir-17∼92 Governs Motor Neuron Subtype Survival by Mediating Nuclear PTEN. Cell Rep 2016; 11:1305-18. [PMID: 26004179 DOI: 10.1016/j.celrep.2015.04.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/17/2015] [Accepted: 04/22/2015] [Indexed: 01/07/2023] Open
Abstract
Motor neurons (MNs) are unique because they project their axons outside of the CNS to innervate the peripheral muscles. Limb-innervating lateral motor column MNs (LMC-MNs) travel substantially to innervate distal limb mesenchyme. How LMC-MNs fine-tune the balance between survival and apoptosis while wiring the sensorimotor circuit en route remains unclear. Here, we show that the mir-17∼92 cluster is enriched in embryonic stem cell (ESC)-derived LMC-MNs and that conditional mir-17∼92 deletion in MNs results in the death of LMC-MNs in vitro and in vivo. mir-17∼92 overexpression rescues MNs from apoptosis, which occurs spontaneously during embryonic development. PTEN is a primary target of mir-17∼92 responsible for LMC-MN degeneration. Additionally, mir-17∼92 directly targets components of E3 ubiquitin ligases, affecting PTEN subcellular localization through monoubiquitination. This miRNA-mediated regulation modulates both target expression and target subcellular localization, providing LMC-MNs with an intricate defensive mechanism that controls their survival.
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213
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Wertz MH, Winden K, Neveu P, Ng SY, Ercan E, Sahin M. Cell-type-specific miR-431 dysregulation in a motor neuron model of spinal muscular atrophy. Hum Mol Genet 2016; 25:2168-2181. [PMID: 27005422 DOI: 10.1093/hmg/ddw084] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/11/2016] [Indexed: 12/17/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal-recessive pediatric neurodegenerative disease characterized by selective loss of spinal motor neurons. It is caused by mutation in the survival of motor neuron 1, SMN1, gene and leads to loss of function of the full-length SMN protein. microRNAs (miRNAs) are small RNAs that are involved in post-transcriptional regulation of gene expression. Prior studies have implicated miRNAs in the pathogenesis of motor neuron disease. We hypothesized that motor neuron-specific miRNA expression changes are involved in their selective vulnerability in SMA. Therefore, we sought to determine the effect of SMN loss on miRNAs and their target mRNAs in spinal motor neurons. We used microarray and RNAseq to profile both miRNA and mRNA expression in primary spinal motor neuron cultures after acute SMN knockdown. By integrating the miRNA:mRNA profiles, a number of dysregulated miRNAs were identified with enrichment in differentially expressed putative mRNA targets. miR-431 expression was highly increased, and a number of its putative mRNA targets were significantly downregulated in motor neurons after SMN loss. Further, we found that miR-431 regulates motor neuron neurite length by targeting several molecules previously identified to play a role in motor neuron axon outgrowth, including chondrolectin. Together, our findings indicate that cell-type-specific dysregulation of miR-431 plays a role in the SMA motor neuron phenotype.
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Affiliation(s)
- Mary H Wertz
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kellen Winden
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Pierre Neveu
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Shi-Yan Ng
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA Neurotherapeutics Laboratory, Institute of Molecular and Cell Biology, A*STAR, Singapore 138673, Singapore
| | - Ebru Ercan
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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214
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Tadros MA, Fuglevand AJ, Brichta AM, Callister RJ. Intrinsic excitability differs between murine hypoglossal and spinal motoneurons. J Neurophysiol 2016; 115:2672-80. [PMID: 26936988 DOI: 10.1152/jn.01114.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/29/2016] [Indexed: 12/12/2022] Open
Abstract
Motoneurons differ in the behaviors they control and their vulnerability to disease and aging. For example, brain stem motoneurons such as hypoglossal motoneurons (HMs) are involved in licking, suckling, swallowing, respiration, and vocalization. In contrast, spinal motoneurons (SMs) innervating the limbs are involved in postural and locomotor tasks requiring higher loads and lower movement velocities. Surprisingly, the properties of these two motoneuron pools have not been directly compared, even though studies on HMs predominate in the literature compared with SMs, especially for adult animals. Here we used whole cell patch-clamp recording to compare the electrophysiological properties of HMs and SMs in age-matched neonatal mice (P7-P10). Passive membrane properties were remarkably similar in HMs and SMs, and afterhyperpolarization properties did not differ markedly between the two populations. HMs had narrower action potentials (APs) and a faster upstroke on their APs compared with SMs. Furthermore, HMs discharged APs at higher frequencies in response to both step and ramp current injection than SMs. Therefore, while HMs and SMs have similar passive properties, they differ in their response to similar levels of depolarizing current. This suggests that each population possesses differing suites of ion channels that allow them to discharge at rates matched to the different mechanical properties of the muscle fibers that drive their distinct motor functions.
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Affiliation(s)
- M A Tadros
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - A J Fuglevand
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona
| | - A M Brichta
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - R J Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
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215
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Sharma A, Lyashchenko AK, Lu L, Nasrabady SE, Elmaleh M, Mendelsohn M, Nemes A, Tapia JC, Mentis GZ, Shneider NA. ALS-associated mutant FUS induces selective motor neuron degeneration through toxic gain of function. Nat Commun 2016; 7:10465. [PMID: 26842965 PMCID: PMC4742863 DOI: 10.1038/ncomms10465] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/14/2015] [Indexed: 12/13/2022] Open
Abstract
Mutations in FUS cause amyotrophic lateral sclerosis (ALS), including some of the most aggressive, juvenile-onset forms of the disease. FUS loss-of-function and toxic gain-of-function mechanisms have been proposed to explain how mutant FUS leads to motor neuron degeneration, but neither has been firmly established in the pathogenesis of ALS. Here we characterize a series of transgenic FUS mouse lines that manifest progressive, mutant-dependent motor neuron degeneration preceded by early, structural and functional abnormalities at the neuromuscular junction. A novel, conditional FUS knockout mutant reveals that postnatal elimination of FUS has no effect on motor neuron survival or function. Moreover, endogenous FUS does not contribute to the onset of the ALS phenotype induced by mutant FUS. These findings demonstrate that FUS-dependent motor degeneration is not due to loss of FUS function, but to the gain of toxic properties conferred by ALS mutations. The mechanism by which FUS mutations cause familial ALS remains unclear. Here, the authors use mouse transgenic models to show that a toxic gain-of-function underlies motor neuron degeneration, and that the toxicity of mutant FUS does not depend on a loss or excess of FUS activity.
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Affiliation(s)
- Aarti Sharma
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 630 W 168th Street, P&S Building, Room 5-423, New York, New York 10032, USA
| | - Alexander K Lyashchenko
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 630 W 168th Street, P&S Building, Room 5-423, New York, New York 10032, USA
| | - Lei Lu
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 630 W 168th Street, P&S Building, Room 5-423, New York, New York 10032, USA
| | - Sara Ebrahimi Nasrabady
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10032, USA
| | - Margot Elmaleh
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 630 W 168th Street, P&S Building, Room 5-423, New York, New York 10032, USA
| | - Monica Mendelsohn
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10032, USA
| | - Adriana Nemes
- Department of Neuroscience, Howard Hughes Medical Institute, Columbia University, New York, New York 10032, USA
| | - Juan Carlos Tapia
- Department of Neuroscience, Columbia University, New York, New York 10032, USA
| | - George Z Mentis
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10032, USA
| | - Neil A Shneider
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 630 W 168th Street, P&S Building, Room 5-423, New York, New York 10032, USA
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216
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Tomassy GS, Dershowitz LB, Arlotta P. Diversity Matters: A Revised Guide to Myelination. Trends Cell Biol 2016; 26:135-147. [PMID: 26442841 PMCID: PMC4727993 DOI: 10.1016/j.tcb.2015.09.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
Abstract
The evolutionary success of the vertebrate nervous system is largely due to a unique structural feature--the myelin sheath, a fatty envelope that surrounds the axons of neurons. By increasing the speed by which electrical signals travel along axons, myelin facilitates neuronal communication between distant regions of the nervous system. We review the cellular and molecular mechanisms that regulate the development of myelin as well as its homeostasis in adulthood. We discuss how finely tuned neuron-oligodendrocyte interactions are central to myelin formation during development and in the adult, and how these interactions can have profound implications for the plasticity of the adult brain. We also speculate how the functional diversity of both neurons and oligodendrocytes may impact on the myelination process in both health and disease.
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Affiliation(s)
- Giulio Srubek Tomassy
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Lori Bowe Dershowitz
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paola Arlotta
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
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217
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Wiese S. Factors influencing the spinal motoneurons in development. Neural Regen Res 2016; 10:1773-6. [PMID: 26807112 PMCID: PMC4705789 DOI: 10.4103/1673-5374.169639] [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] [Indexed: 11/04/2022] Open
Abstract
The development of the spinal cord needs a concerted interaction of transcription factors activating diverse genes and signals from outside acting on the specification of the different cells. Signals have to act on the segments of the embryo as well as on the cranial-caudal axis and the dorso-ventral axis. Additionally the axons of the motoneurons have to cross the central nervous system barrier to connect to the periphery. Intensive anatomical studies have been followed by molecular characterization of the different subsets of transcription factors that are expressed by cells of the developing spinal cord. Here, intensive studies for the most important appearing cells, the motoneurons, have resulted in a good knowledge on the expression patterns of these proteins. Nonetheless motoneurons are by far not the only important cells and the concert activity of all cells besides them is necessary for the correct function and integrity of motoneurons within the spinal cord. This article will briefly summarize the different aspects on spinal cord development and focuses on the differentiation as well as the functionalization of motoneurons.
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Affiliation(s)
- Stefan Wiese
- Faculty for Biology and Biotechnology, Group for Molecular Cell Biology, Universitaetsstr. 150, Ruhr University Bochum, D-44801 Bochum, Germany
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218
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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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219
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Emerging Roles of Filopodia and Dendritic Spines in Motoneuron Plasticity during Development and Disease. Neural Plast 2015; 2016:3423267. [PMID: 26843990 PMCID: PMC4710938 DOI: 10.1155/2016/3423267] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/10/2015] [Accepted: 09/21/2015] [Indexed: 01/16/2023] Open
Abstract
Motoneurons develop extensive dendritic trees for receiving excitatory and inhibitory synaptic inputs to perform a variety of complex motor tasks. At birth, the somatodendritic domains of mouse hypoglossal and lumbar motoneurons have dense filopodia and spines. Consistent with Vaughn's synaptotropic hypothesis, we propose a developmental unified-hybrid model implicating filopodia in motoneuron spinogenesis/synaptogenesis and dendritic growth and branching critical for circuit formation and synaptic plasticity at embryonic/prenatal/neonatal period. Filopodia density decreases and spine density initially increases until postnatal day 15 (P15) and then decreases by P30. Spine distribution shifts towards the distal dendrites, and spines become shorter (stubby), coinciding with decreases in frequency and increases in amplitude of excitatory postsynaptic currents with maturation. In transgenic mice, either overexpressing the mutated human Cu/Zn-superoxide dismutase (hSOD1G93A) gene or deficient in GABAergic/glycinergic synaptic transmission (gephyrin, GAD-67, or VGAT gene knockout), hypoglossal motoneurons develop excitatory glutamatergic synaptic hyperactivity. Functional synaptic hyperactivity is associated with increased dendritic growth, branching, and increased spine and filopodia density, involving actin-based cytoskeletal and structural remodelling. Energy-dependent ionic pumps that maintain intracellular sodium/calcium homeostasis are chronically challenged by activity and selectively overwhelmed by hyperactivity which eventually causes sustained membrane depolarization leading to excitotoxicity, activating microglia to phagocytose degenerating neurons under neuropathological conditions.
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220
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Generating Diverse Spinal Motor Neuron Subtypes from Human Pluripotent Stem Cells. Stem Cells Int 2015; 2016:1036974. [PMID: 26823667 PMCID: PMC4707335 DOI: 10.1155/2016/1036974] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 09/14/2015] [Indexed: 12/18/2022] Open
Abstract
Resolving the mechanisms underlying human neuronal diversification remains a major challenge in developmental and applied neurobiology. Motor neurons (MNs) represent a diverse pool of neuronal subtypes exhibiting differential vulnerability in different human neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The ability to predictably manipulate MN subtype lineage restriction from human pluripotent stem cells (PSCs) will form the essential basis to establishing accurate, clinically relevant in vitro disease models. I first overview motor neuron developmental biology to provide some context for reviewing recent studies interrogating pathways that influence the generation of MN diversity. I conclude that motor neurogenesis from PSCs provides a powerful reductionist model system to gain insight into the developmental logic of MN subtype diversification and serves more broadly as a leading exemplar of potential strategies to resolve the molecular basis of neuronal subclass differentiation within the nervous system. These studies will in turn permit greater mechanistic understanding of differential MN subtype vulnerability using in vitro human disease models.
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221
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Transcriptional regulation of mouse hypoglossal motor neuron somatotopic map formation. Brain Struct Funct 2015; 221:4187-4202. [DOI: 10.1007/s00429-015-1160-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/24/2015] [Indexed: 11/25/2022]
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222
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Stark DA, Coffey NJ, Pancoast HR, Arnold LL, Walker JPD, Vallée J, Robitaille R, Garcia ML, Cornelison DDW. Ephrin-A3 promotes and maintains slow muscle fiber identity during postnatal development and reinnervation. J Cell Biol 2015; 211:1077-91. [PMID: 26644518 PMCID: PMC4674275 DOI: 10.1083/jcb.201502036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 10/22/2015] [Indexed: 11/28/2022] Open
Abstract
Each adult mammalian skeletal muscle has a unique complement of fast and slow myofibers, reflecting patterns established during development and reinforced via their innervation by fast and slow motor neurons. Existing data support a model of postnatal "matching" whereby predetermined myofiber type identity promotes pruning of inappropriate motor axons, but no molecular mechanism has yet been identified. We present evidence that fiber type-specific repulsive interactions inhibit innervation of slow myofibers by fast motor axons during both postnatal maturation of the neuromuscular junction and myofiber reinnervation after injury. The repulsive guidance ligand ephrin-A3 is expressed only on slow myofibers, whereas its candidate receptor, EphA8, localizes exclusively to fast motor endplates. Adult mice lacking ephrin-A3 have dramatically fewer slow myofibers in fast and mixed muscles, and misexpression of ephrin-A3 on fast myofibers followed by denervation/reinnervation promotes their respecification to a slow phenotype. We therefore conclude that Eph/ephrin interactions guide the fiber type specificity of neuromuscular interactions during development and adult life.
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Affiliation(s)
- Danny A Stark
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - Nathan J Coffey
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211
| | - Hannah R Pancoast
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211
| | - Laura L Arnold
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - J Peyton D Walker
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - Joanne Vallée
- Département de Neurosciences, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Richard Robitaille
- Département de Neurosciences, Université de Montréal, Montréal, Québec H3C 3J7, Canada Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Michael L Garcia
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - D D W Cornelison
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
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223
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Wiese S, Faissner A. The role of extracellular matrix in spinal cord development. Exp Neurol 2015; 274:90-9. [DOI: 10.1016/j.expneurol.2015.05.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/13/2015] [Accepted: 05/25/2015] [Indexed: 01/06/2023]
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224
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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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225
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Powis RA, Gillingwater TH. Selective loss of alpha motor neurons with sparing of gamma motor neurons and spinal cord cholinergic neurons in a mouse model of spinal muscular atrophy. J Anat 2015; 228:443-51. [PMID: 26576026 DOI: 10.1111/joa.12419] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2015] [Indexed: 02/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease characterised primarily by loss of lower motor neurons from the ventral grey horn of the spinal cord and proximal muscle atrophy. Recent experiments utilising mouse models of SMA have demonstrated that not all motor neurons are equally susceptible to the disease, revealing that other populations of neurons can also be affected. Here, we have extended investigations of selective vulnerability of neuronal populations in the spinal cord of SMA mice to include comparative assessments of alpha motor neuron (α-MN) and gamma motor neuron (γ-MN) pools, as well as other populations of cholinergic neurons. Immunohistochemical analyses of late-symptomatic SMA mouse spinal cord revealed that numbers of α-MNs were significantly reduced at all levels of the spinal cord compared with controls, whereas numbers of γ-MNs remained stable. Likewise, the average size of α-MN cell somata was decreased in SMA mice with no change occurring in γ-MNs. Evaluation of other pools of spinal cord cholinergic neurons revealed that pre-ganglionic sympathetic neurons, central canal cluster interneurons, partition interneurons and preganglionic autonomic dorsal commissural nucleus neuron numbers all remained unaffected in SMA mice. Taken together, these findings indicate that α-MNs are uniquely vulnerable among cholinergic neuron populations in the SMA mouse spinal cord, with γ-MNs and other cholinergic neuronal populations being largely spared.
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Affiliation(s)
- Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.,Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.,Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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226
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Faunes M, Oñate-Ponce A, Fernández-Collemann S, Henny P. Excitatory and inhibitory innervation of the mouse orofacial motor nuclei: A stereological study. J Comp Neurol 2015. [DOI: 10.1002/cne.23862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Macarena Faunes
- Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina; Pontificia Universidad Católica de Chile; Santiago Chile
- Centro Interdisciplinario de Neurociencias; Pontificia Universidad Católica de Chile; Santiago Chile
- Sensory and Motor Systems Group, Department of Anatomy with Radiology, Faculty of Medical and Health Sciences; University of Auckland; Private Bag 92019, Grafton 1023 Auckland New Zealand
| | - Alejandro Oñate-Ponce
- Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina; Pontificia Universidad Católica de Chile; Santiago Chile
- Centro Interdisciplinario de Neurociencias; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Sara Fernández-Collemann
- Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina; Pontificia Universidad Católica de Chile; Santiago Chile
- Centro Interdisciplinario de Neurociencias; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Pablo Henny
- Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina; Pontificia Universidad Católica de Chile; Santiago Chile
- Centro Interdisciplinario de Neurociencias; Pontificia Universidad Católica de Chile; Santiago Chile
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227
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Modeling amyotrophic lateral sclerosis in pure human iPSc-derived motor neurons isolated by a novel FACS double selection technique. Neurobiol Dis 2015; 82:269-280. [DOI: 10.1016/j.nbd.2015.06.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/30/2015] [Accepted: 06/17/2015] [Indexed: 01/01/2023] Open
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228
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Basaldella E, Takeoka A, Sigrist M, Arber S. Multisensory Signaling Shapes Vestibulo-Motor Circuit Specificity. Cell 2015; 163:301-12. [DOI: 10.1016/j.cell.2015.09.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/22/2015] [Accepted: 09/01/2015] [Indexed: 12/31/2022]
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229
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Bagher Z, Ebrahimi-Barough S, Azami M, Safa M, Joghataei MT. Cellular activity of Wharton's Jelly-derived mesenchymal stem cells on electrospun fibrous and solvent-cast film scaffolds. J Biomed Mater Res A 2015; 104:218-26. [DOI: 10.1002/jbm.a.35555] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/14/2015] [Accepted: 08/07/2015] [Indexed: 01/17/2023]
Affiliation(s)
- Zohreh Bagher
- ENT-Head and Neck Research Center and Department; Rasoul Akram Hospital, Iran University of Medical Sciences & Health Services; Tehran Iran
- Department of Tissue Engineering and Regenerative Medicine; School of Advanced Technologies in Medicine, Iran University of Medical Sciences; Tehran Iran
| | - Somayeh Ebrahimi-Barough
- Department of Tissue Engineering and Applied Cell Sciences; School of Advanced Technologies in Medicine, Tehran University of Medical Sciences; Tehran Iran
| | - Mahmoud Azami
- Department of Tissue Engineering and Applied Cell Sciences; School of Advanced Technologies in Medicine, Tehran University of Medical Sciences; Tehran Iran
| | - Majid Safa
- Cellular and Molecular Research Center; Iran University of Medical Sciences; Tehran Iran
- Department of Tissue Engineering and Regenerative Medicine; School of Advanced Technologies in Medicine, Iran University of Medical Sciences; Tehran Iran
| | - Mohammad Taghi Joghataei
- Cellular and Molecular Research Center; Iran University of Medical Sciences; Tehran Iran
- Department of Tissue Engineering and Regenerative Medicine; School of Advanced Technologies in Medicine, Iran University of Medical Sciences; Tehran Iran
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230
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Murray LM, Beauvais A, Gibeault S, Courtney NL, Kothary R. Transcriptional profiling of differentially vulnerable motor neurons at pre-symptomatic stage in the Smn (2b/-) mouse model of spinal muscular atrophy. Acta Neuropathol Commun 2015; 3:55. [PMID: 26374403 PMCID: PMC4570693 DOI: 10.1186/s40478-015-0231-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION The term motor neuron disease encompasses a spectrum of disorders in which motor neurons are the lost. Importantly, while some motor neurons are lost early in disease and others remain intact at disease end-stage. This creates a valuable experimental paradigm to investigate the factors that regulate motor neuron vulnerability. Spinal muscular atrophy is a childhood motor neuron disease caused by mutations or deletions in the SMN1 gene. Here, we have performed transcriptional analysis on differentially vulnerable motor neurons from an intermediate mouse model of Spinal muscular atrophy at a presymptomatic time point. RESULTS We have characterised two differentially vulnerable populations, differing in the level neuromuscular junction loss. Transcriptional analysis on motor neuron cell bodies revealed that reduced Smn levels correlate with a reduction of transcripts associated with the ribosome, rRNA binding, ubiquitination and oxidative phosphorylation. Furthermore, P53 pathway activation precedes neuromuscular junction loss, suggesting that denervation may be a consequence, rather than a cause of motor neuron death in Spinal muscular atrophy. Finally, increased vulnerability correlates with a decrease in the positive regulation of DNA repair. CONCLUSIONS This study identifies pathways related to the function of Smn and associated with differential motor unit vulnerability, thus presenting a number of exciting targets for future therapeutic development.
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231
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Durand J, Filipchuk A, Pambo-Pambo A, Amendola J, Borisovna Kulagina I, Guéritaud JP. Developing electrical properties of postnatal mouse lumbar motoneurons. Front Cell Neurosci 2015; 9:349. [PMID: 26388736 PMCID: PMC4557103 DOI: 10.3389/fncel.2015.00349] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/20/2015] [Indexed: 11/13/2022] Open
Abstract
We studied the rapid changes in electrical properties of lumbar motoneurons between postnatal days 3 and 9 just before mice weight-bear and walk. The input conductance and rheobase significantly increased up to P8. A negative correlation exists between the input resistance (Rin) and rheobase. Both parameters are significantly correlated with the total dendritic surface area of motoneurons, the largest motoneurons having the lowest Rin and the highest rheobase. We classified the motoneurons into three groups according to their discharge firing patterns during current pulse injection (transient, delayed onset, sustained). The delayed onset firing type has the highest rheobase and the fastest action potential (AP) whereas the transient firing group has the lowest rheobase and the less mature AP. We found 32 and 10% of motoneurons with a transient firing at P3-P5 and P8, respectively. About 20% of motoneurons with delayed onset firing were detected at P8. At P9, all motoneurons exhibit a sustained firing. We defined five groups of motoneurons according to their discharge firing patterns in response to ascending and descending current ramps. In addition to the four classical types, we defined a fifth type called transient for the quasi-absence of discharge during the descending phase of the ramp. This transient type represents about 40% between P3-P5 and tends to disappear with age. Types 1 and 2 (linear and clockwise hysteresis) are the most preponderant at P6-P7. Types 3 and 4 (prolonged sustained and counter clockwise hysteresis) emerge at P8-P9. The emergence of types 3 and 4 probably depends on the maturation of L type calcium channels in the dendrites of motoneurons. No correlation was found between groups defined by step or triangular ramp of currents with the exception of transient firing patterns. Our data support the idea that a switch in the electrical properties of lumbar motoneurons might exist in the second postnatal week of life in mice.
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Affiliation(s)
- Jacques Durand
- Institut de Neurosciences de la Timone, Aix Marseille Université - CNRS, UMR 7289 Marseille, France
| | - Anton Filipchuk
- Institut de Neurosciences de la Timone, Aix Marseille Université - CNRS, UMR 7289 Marseille, France
| | - Arnaud Pambo-Pambo
- Institut de Neurosciences de la Timone, Aix Marseille Université - CNRS, UMR 7289 Marseille, France
| | - Julien Amendola
- Institut de Neurosciences de la Timone, Aix Marseille Université - CNRS, UMR 7289 Marseille, France
| | | | - Jean-Patrick Guéritaud
- Institut de Neurosciences de la Timone, Aix Marseille Université - CNRS, UMR 7289 Marseille, France
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232
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Smith KS, Rush RA, Rogers ML. Characterization and changes in neurotrophin receptor p75-Expressing motor neurons in SOD1(G93A) G1H mice [corrected]. J Comp Neurol 2015; 523:1664-82. [PMID: 25711805 DOI: 10.1002/cne.23763] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 12/14/2022]
Abstract
Mice with high numbers of the Cu/Zn superoxide dismutase-1 G93A transgene (SOD1(G93A) G1H) have become the most commonly used animal model to study amyotrophic lateral sclerosis. This study investigated changes in size, numbers, and cell stress/death markers of motor neuron numbers in G1H mice that re-express the common p75 neurotrophin receptor (p75NTR). SOD1(G93A) G1H mice and age-matched C57BL/6J controls at 60, 80, 100, 120 days and end stage/140 days were analyzed for p75NTR, choline acetyltransferase (ChAT), activating transcription factor 3 (ATF3), and cleaved caspase-3. In addition, motor neuron counts and soma sizes were recorded. Motor neurons re-expressing p75NTR in SOD1(G93A) G1H mice were first observed at 80 days, and this continued to 140 days, peaking at 100-120 days at ∼5%. The soma area of motor neurons re-expressing p75NTR was always 600-800 µm(2) , suggesting that these are alpha motor neurons, which was confirmed after examination of somas post injection of a retrogradely transported antibody to p75NTR in 110-day-old SOD1(G93A) G1H mice. In motor neurons not re-expressing p75NTR, the frequency of small soma 200-400 µm2 motor neurons increased, whereas the larger 600-900 µm2 motor neurons decreased with progression, indicating that large motor neurons were dying off and shrinking in the process. There was minimal coexpression of p75NTR with ATF3, a marker for cell stress, but 85% coexpressed the apoptotic marker cleaved caspase-3. These findings indicate that in SOD1(G93A) G1H mice, p75NTR re-expression is detectable from 80 days in a small population of large motor neurons that represent 5% of the total motor neurons. Furthermore, p75NTR re-expression occurs in larger alpha motor neurons that express cleaved caspsase-3 and are destined to die.
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Affiliation(s)
- Kevin S Smith
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia, 5001
| | - Robert A Rush
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia, 5001
| | - Mary-Louise Rogers
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia, 5001
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233
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Mutation screen reveals novel variants and expands the phenotypes associated with DYNC1H1. J Neurol 2015; 262:2124-34. [PMID: 26100331 DOI: 10.1007/s00415-015-7727-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 12/21/2022]
Abstract
Dynein, cytoplasmic 1, heavy chain 1 (DYNC1H1) encodes a necessary subunit of the cytoplasmic dynein complex, which traffics cargo along microtubules. Dominant DYNC1H1 mutations are implicated in neural diseases, including spinal muscular atrophy with lower extremity dominance (SMA-LED), intellectual disability with neuronal migration defects, malformations of cortical development, and Charcot-Marie-Tooth disease, type 2O. We hypothesized that additional variants could be found in these and novel motoneuron and related diseases. Therefore, we analyzed our database of 1024 whole exome sequencing samples of motoneuron and related diseases for novel single nucleotide variations. We filtered these results for significant variants, which were further screened using segregation analysis in available family members. Analysis revealed six novel, rare, and highly conserved variants. Three of these are likely pathogenic and encompass a broad phenotypic spectrum with distinct disease clusters. Our findings suggest that DYNC1H1 variants can cause not only lower, but also upper motor neuron disease. It thus adds DYNC1H1 to the growing list of spastic paraplegia related genes in microtubule-dependent motor protein pathways.
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234
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Tamura Y, Kitaoka Y, Matsunaga Y, Hoshino D, Hatta H. Daily heat stress treatment rescues denervation-activated mitochondrial clearance and atrophy in skeletal muscle. J Physiol 2015; 593:2707-20. [PMID: 25900738 DOI: 10.1113/jp270093] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/13/2015] [Indexed: 01/11/2023] Open
Abstract
KEY POINTS Traumatic nerve injury or nerve disease leads to denervation and severe muscle atrophy. Recent evidence shows that mitochondrial loss could be a key mediator of skeletal muscle atrophy. Here, we show that daily heat stress treatment rescues denervation-induced loss of mitochondria and concomitant muscle atrophy. We also found that denervation-activated autophagy-dependent mitochondrial clearance (mitophagy) was suppressed by daily heat stress treatment. The molecular basis of this observation is explained by our results showing that heat stress treatment attenuates the increase of key proteins that regulate the tagging step for mitochondrial clearance and the intermediate step of autophagosome formation in denervated muscle. These findings contribute to the better understanding of mitochondrial quality control in denervated muscle from a translational perspective and provide a mechanism behind the attenuation of muscle wasting by heat stress. ABSTRACT Traumatic nerve injury or motor neuron disease leads to denervation and severe muscle atrophy. Recent evidence indicates that loss of mitochondria and the related reduction in oxidative capacity could be key mediators of skeletal muscle atrophy. As our previous study showed that heat stress increased the numbers of mitochondria in skeletal muscle, we evaluated whether heat stress treatment could have a beneficial impact on denervation-induced loss of mitochondria and subsequent muscle atrophy. Here, we report that daily heat stress treatment (mice placed in a chamber with a hot environment; 40°C, 30 min day(-1) , for 7 days) rescues the following parameters: (i) muscle atrophy (decreased gastrocnemius muscle mass); (ii) loss of mitochondrial content (decreased levels of ubiquinol-cytochrome c reductase core protein II, cytochrome c oxidase subunits I and IV and voltage-dependent anion channel protein); and (iii) reduction in oxidative capacity (reduced maximal activities of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase) in denervated muscle (produced by unilateral sciatic nerve transection). In order to gain a better understanding of the above mitochondrial adaptations, we also examined the effects of heat stress on autophagy-dependent mitochondrial clearance (mitophagy). Daily heat stress normalized denervation-activated induction of mitophagy (increased mitochondrial microtubule-associated protein 1A/1B-light chain3-II (LC3-II) with and without blocker of autophagosome clearance). The molecular basis of this observation was explained by the results that heat stress attenuated the denervation-induced increase in key proteins that regulate the following steps: (i) the tagging step of mitochondrial clearance (increased mitochondrial Parkin, ubiquitin-conjugated, P62/sequestosome 1 (P62/SQSTM1)); and (ii) the elongation step of autophagosome formation (increased Atg5-Atg12 conjugate and Atg16L). Overall, our results contribute to the better understanding of mitochondrial quality control and the mechanisms behind the attenuation of muscle wasting by heat stress in denervated skeletal muscle.
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Affiliation(s)
- Yuki Tamura
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Yu Kitaoka
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Yutaka Matsunaga
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Daisuke Hoshino
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
| | - Hideo Hatta
- Department of Sports Sciences, The University of Tokyo, Tokyo, Japan
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235
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Yan Y, Wladyka C, Fujii J, Sockanathan S. Prdx4 is a compartment-specific H2O2 sensor that regulates neurogenesis by controlling surface expression of GDE2. Nat Commun 2015; 6:7006. [PMID: 25943695 PMCID: PMC4432624 DOI: 10.1038/ncomms8006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/23/2015] [Indexed: 02/07/2023] Open
Abstract
Neural progenitors and terminally differentiated neurons show distinct redox profiles, suggesting that coupled-redox cascades regulate the initiation and progression of neuronal differentiation. Discrete cellular compartments have different redox environments and how they contribute to differentiation is unclear. Here we show that Prdx4, an endoplasmic reticulum (ER) enzyme that metabolizes H2O2, acts as a tunable regulator of neurogenesis via its compartmentalized thiol-oxidative function. Prdx4 ablation causes premature motor neuron differentiation and progenitor depletion, leading to imbalances in subtype-specific motor neurons. GDE2, a six-transmembrane protein that induces differentiation by downregulating Notch signalling through surface cleavage of GPI-anchored proteins, is targeted by Prdx4 oxidative activity. Prdx4 dimers generated by H2O2 metabolism oxidize two cysteine residues within the GDE2 enzymatic domain, which blocks GDE2 trafficking to the plasma membrane and prevents GDE2 neurogeneic function. Thus, Prdx4 oxidative activity acts as a sensor to directly couple neuronal differentiation with redox environments in the ER. Neuron differentiation is marked by changes in intracellular redox status. Here Yan et al. show that ER-resident peroxiredoxin 4 senses increased H2O2 and prevents the surface expression of differentiation-promoting GDE2 by modifying cysteine residues within GDE2.
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Affiliation(s)
- Ye Yan
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, PCTB1004, 725 N Wolfe Street, Baltimore, Maryland 21205, USA
| | - Cynthia Wladyka
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, PCTB1004, 725 N Wolfe Street, Baltimore, Maryland 21205, USA
| | - Junichi Fujii
- Department of Biochemistry and Molecular Biology, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Shanthini Sockanathan
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, PCTB1004, 725 N Wolfe Street, Baltimore, Maryland 21205, USA
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Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable.
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237
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Foxp1-mediated programming of limb-innervating motor neurons from mouse and human embryonic stem cells. Nat Commun 2015; 6:6778. [PMID: 25868900 PMCID: PMC4397664 DOI: 10.1038/ncomms7778] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 02/26/2015] [Indexed: 01/11/2023] Open
Abstract
Spinal motor neurons (MNs) control diverse motor tasks including respiration, posture and locomotion that are disrupted by neurodegenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Methods directing MN differentiation from stem cells have been developed to enable disease modelling in vitro. However, most protocols produce only a limited subset of endogenous MN subtypes. Here we demonstrate that limb-innervating lateral motor column (LMC) MNs can be efficiently generated from mouse and human embryonic stem cells through manipulation of the transcription factor Foxp1. Foxp1-programmed MNs exhibit features of medial and lateral LMC MNs including expression of specific motor pool markers and axon guidance receptors. Importantly, they preferentially project axons towards limb muscle explants in vitro and distal limb muscles in vivo upon transplantation-hallmarks of bona fide LMC MNs. These results present an effective approach for generating specific MN populations from stem cells for studying MN development and disease.
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238
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Homeostatic dysregulation in membrane properties of masticatory motoneurons compared with oculomotor neurons in a mouse model for amyotrophic lateral sclerosis. J Neurosci 2015; 35:707-20. [PMID: 25589764 DOI: 10.1523/jneurosci.1682-14.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative motoneuron disease with presently no cure. Motoneuron (MN) hyperexcitability is commonly observed in ALS and is suggested to be a precursor for excitotoxic cell death. However, it is unknown whether hyperexcitability also occurs in MNs that are resistant to degeneration. Second, it is unclear whether all the MNs within homogeneous motor pools would present similar susceptibility to excitability changes since high-threshold MNs innervating fast fatigable muscle fibers selectively degenerate compared with low-threshold MNs innervating fatigue resistant slow muscle fibers. Therefore, we concurrently examined the excitability of ALS-vulnerable trigeminal motoneurons (TMNs) controlling jaw musculature and ALS-resistant oculomotor neurons (OMNs) controlling eye musculature in a well studied SOD1(G93A) ALS mouse model using in vitro patch-clamp electrophysiology at presymptomatic ages P8-P12. Our results show that hyperexcitability is not a global change among all the MNs, although mutant SOD1 is ubiquitously expressed. Instead, complex changes occur in ALS-vulnerable TMNs based on motor unit type and discharge characteristics. Firing threshold decreases among high-threshold TMNs and increases in a subpopulation of low-threshold TMNs. The latter group was identified based on their linear frequency-current responses to triangular ramp current injections. Such complex changes in MN recruitment were absent in ALS-resistant OMNs. We simulated the observed complex changes in TMN excitability using a computer-based jaw closer motor pool model. Model results suggest that hypoexcitability may indeed represent emerging disease symptomology that causes resistance in muscle force initiation. Identifying the cellular and molecular properties of these hypoexcitable cells may guide effective therapeutic strategies in ALS.
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239
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Structural and kinetic analysis of protein-aggregate strains in vivo using binary epitope mapping. Proc Natl Acad Sci U S A 2015; 112:4489-94. [PMID: 25802384 DOI: 10.1073/pnas.1419228112] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Despite considerable progress in uncovering the molecular details of protein aggregation in vitro, the cause and mechanism of protein-aggregation disease remain poorly understood. One reason is that the amount of pathological aggregates in neural tissue is exceedingly low, precluding examination by conventional approaches. We present here a method for determination of the structure and quantity of aggregates in small tissue samples, circumventing the above problem. The method is based on binary epitope mapping using anti-peptide antibodies. We assessed the usefulness and versatility of the method in mice modeling the neurodegenerative disease amyotrophic lateral sclerosis, which accumulate intracellular aggregates of superoxide dismutase-1. Two strains of aggregates were identified with different structural architectures, molecular properties, and growth kinetics. Both were different from superoxide dismutase-1 aggregates generated in vitro under a variety of conditions. The strains, which seem kinetically under fragmentation control, are associated with different disease progressions, complying with and adding detail to the growing evidence that seeding, infectivity, and strain dependence are unifying principles of neurodegenerative disease.
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240
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Roselli F, Caroni P. From Intrinsic Firing Properties to Selective Neuronal Vulnerability in Neurodegenerative Diseases. Neuron 2015; 85:901-10. [DOI: 10.1016/j.neuron.2014.12.063] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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241
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Bloch-Gallego E. Mechanisms controlling neuromuscular junction stability. Cell Mol Life Sci 2015; 72:1029-43. [PMID: 25359233 PMCID: PMC11113273 DOI: 10.1007/s00018-014-1768-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/06/2014] [Accepted: 10/17/2014] [Indexed: 01/01/2023]
Abstract
The neuromuscular junction (NMJ) is the synaptic connection between motor neurons and muscle fibers. It is involved in crucial processes such as body movements and breathing. Its proper development requires the guidance of motor axons toward their specific targets, the development of multi-innervated myofibers, and a selective synapse stabilization. It first consists of the removal of excessive motor axons on myofibers, going from multi-innervation to a single innervation of each myofiber. Whereas guidance cues of motor axons toward their specific muscular targets are well characterized, only few molecular and cellular cues have been reported as clues for selecting and stabilizing specific neuromuscular junctions. We will first provide a brief summary on NMJ development. We will then review molecular cues that are involved in NMJ stabilization, in both pre- and post-synaptic compartments, considering motor neurons and Schwann cells on the one hand, and muscle on the other hand. We will provide links with pathologies and highlight advances that can be brought both by basic research on NMJ development and clinical data resulting from the analyses of neurodegeneration of synaptic connections to obtain a better understanding of this process. The goal of this review is to highlight the findings toward understanding the roles of poly- or single-innervations and the underlying mechanisms of NMJ stabilization.
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Affiliation(s)
- Evelyne Bloch-Gallego
- Institut Cochin, INSERM U. 1016, CNRS UMR 8104, University Paris Descartes 24, rue du Fbg St-Jacques, 75014, Paris, France,
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242
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Zahavi EE, Ionescu A, Gluska S, Gradus T, Ben-Yaakov K, Perlson E. A compartmentalized microfluidic neuromuscular co-culture system reveals spatial aspects of GDNF functions. J Cell Sci 2015; 128:1241-52. [PMID: 25632161 PMCID: PMC4359927 DOI: 10.1242/jcs.167544] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bidirectional molecular communication between the motoneuron and the muscle is vital for neuromuscular junction (NMJ) formation and maintenance. The molecular mechanisms underlying such communication are of keen interest and could provide new targets for intervention in motoneuron disease. Here, we developed a microfluidic platform with motoneuron cell bodies on one side and muscle cells on the other, connected by motor axons extending through microgrooves to form functional NMJs. Using this system, we were able to differentiate between the proximal and distal effects of oxidative stress and glial-derived neurotrophic factor (GDNF), demonstrating a dying-back degeneration and retrograde transmission of pro-survival signaling, respectively. Furthermore, we show that GDNF acts differently on motoneuron axons versus soma, promoting axonal growth and innervation only when applied locally to axons. Finally, we track for the first time the retrograde transport of secreted GDNF from muscle to neuron. Thus, our data suggests spatially distinct effects of GDNF – facilitating growth and muscle innervation at axon terminals and survival pathways in the soma.
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Affiliation(s)
- Eitan Erez Zahavi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ariel Ionescu
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shani Gluska
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tal Gradus
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Keren Ben-Yaakov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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243
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Dirren E, Aebischer J, Rochat C, Towne C, Schneider BL, Aebischer P. SOD1 silencing in motoneurons or glia rescues neuromuscular function in ALS mice. Ann Clin Transl Neurol 2015; 2:167-84. [PMID: 25750921 PMCID: PMC4338957 DOI: 10.1002/acn3.162] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 11/24/2014] [Indexed: 01/09/2023] Open
Abstract
Objective Amyotrophic lateral sclerosis is an incurable disorder mainly characterized by motoneuron degeneration. Mutations in the superoxide dismutase 1 (SOD1) gene account for 20% of familial forms of the disease. Mutant SOD1 exerts multiple pathogenic effects through the gain of toxic properties in both neurons and glial cells. Here, we compare AAV-based gene therapy suppressing expression of mutant SOD1 in either motoneurons or astrocytes. Methods AAV vectors encoding microRNA against human SOD1 were administered to G93ASOD1 mice either by intracerebroventricular injections in pups or by lumbar intrathecal injections in adults. Vector systems were designed to suppress SOD1 expression predominantly in either spinal motoneurons or astrocytes. Electrophysiological and behavioral tests were performed on treated animals to evaluate disease progression. Results Following vector injection in G93ASOD1 pups, efficient silencing of SOD1 expression was achieved in motoneurons and/or astrocytes. Most complete protection of motor units was obtained when targeting human SOD1 predominantly in motoneurons. Suppressing SOD1 mainly in astrocytes led to preserved muscle innervation despite only partial protection of spinal motoneurons. In both cases, injection in pups led to full recovery of neuromuscular function and significantly prolonged survival. Vector injections in adult mice also achieved significant protection of neuromuscular function, which was highest when motoneurons were targeted. Interpretation These results suggest that AAV-mediated SOD1 silencing is an effective approach to prevent motoneuron degeneration caused by SOD1 mutation. AAV vectors suppressing SOD1 in motoneurons delay disease onset and show effective neuroprotection. On the other hand, AAV-based SOD1 silencing in astrocytes rescues neuromuscular function following initial denervation.
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Affiliation(s)
- Elisabeth Dirren
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
| | - Julianne Aebischer
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
| | - Cylia Rochat
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
| | - Christopher Towne
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
| | - Patrick Aebischer
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne, Switzerland
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Filézac de L'Etang A, Maharjan N, Cordeiro Braña M, Ruegsegger C, Rehmann R, Goswami A, Roos A, Troost D, Schneider BL, Weis J, Saxena S. Marinesco-Sjögren syndrome protein SIL1 regulates motor neuron subtype-selective ER stress in ALS. Nat Neurosci 2015; 18:227-38. [PMID: 25559081 DOI: 10.1038/nn.3903] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/18/2014] [Indexed: 12/13/2022]
Abstract
Mechanisms underlying motor neuron subtype-selective endoplasmic reticulum (ER) stress and associated axonal pathology in amyotrophic lateral sclerosis (ALS) remain unclear. Here we show that the molecular environment of the ER between motor neuron subtypes is distinct, with characteristic signatures. We identify cochaperone SIL1, mutated in Marinesco-Sjögren syndrome (MSS), as being robustly expressed in disease-resistant slow motor neurons but not in ER stress-prone fast-fatigable motor neurons. In a mouse model of MSS, we demonstrate impaired ER homeostasis in motor neurons in response to loss of SIL1 function. Loss of a single functional Sil1 allele in an ALS mouse model (SOD1-G93A) enhanced ER stress and exacerbated ALS pathology. In SOD1-G93A mice, SIL1 levels were progressively and selectively reduced in vulnerable fast-fatigable motor neurons. Mechanistically, reduction in SIL1 levels was associated with lowered excitability of fast-fatigable motor neurons, further influencing expression of specific ER chaperones. Adeno-associated virus-mediated delivery of SIL1 to familial ALS motor neurons restored ER homeostasis, delayed muscle denervation and prolonged survival.
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Affiliation(s)
- Audrey Filézac de L'Etang
- 1] Institute of Cell Biology, University of Bern, Bern, Switzerland. [2] Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Niran Maharjan
- 1] Institute of Cell Biology, University of Bern, Bern, Switzerland. [2] Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Céline Ruegsegger
- 1] Institute of Cell Biology, University of Bern, Bern, Switzerland. [2] Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ruth Rehmann
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Anand Goswami
- Institute of Neuropathology, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital, Aachen, Germany
| | - Andreas Roos
- Institute of Neuropathology, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital, Aachen, Germany
| | - Dirk Troost
- Division of Neuropathology, Department of Pathology, Academic Medical Centre, Amsterdam, the Netherlands
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Joachim Weis
- Institute of Neuropathology, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital, Aachen, Germany
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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245
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Abstract
Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS.
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Affiliation(s)
- Francesco Roselli
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Pico Caroni
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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246
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Mühling T, Duda J, Weishaupt JH, Ludolph AC, Liss B. Elevated mRNA-levels of distinct mitochondrial and plasma membrane Ca(2+) transporters in individual hypoglossal motor neurons of endstage SOD1 transgenic mice. Front Cell Neurosci 2014; 8:353. [PMID: 25452714 PMCID: PMC4231948 DOI: 10.3389/fncel.2014.00353] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/08/2014] [Indexed: 12/13/2022] Open
Abstract
Disturbances in Ca2+ homeostasis and mitochondrial dysfunction have emerged as major pathogenic features in familial and sporadic forms of Amyotrophic Lateral Sclerosis (ALS), a fatal degenerative motor neuron disease. However, the distinct molecular ALS-pathology remains unclear. Recently, an activity-dependent Ca2+ homeostasis deficit, selectively in highly vulnerable cholinergic motor neurons in the hypoglossal nucleus (hMNs) from a common ALS mouse model, the endstage superoxide dismutase SOD1G93A transgenic mouse, was described. This functional deficit was defined by a reduced hMN mitochondrial Ca2+ uptake capacity and elevated Ca2+ extrusion across the plasma membrane. To address the underlying molecular mechanisms, here we quantified mRNA-levels of respective potential mitochondrial and plasma membrane Ca2+ transporters in individual, choline-acetyltransferase (ChAT) positive hMNs from wildtype (WT) and endstage SOD1G93A mice, by combining UV laser microdissection with RT-qPCR techniques, and specific data normalization. As ChAT cDNA levels as well as cDNA and genomic DNA levels of the mitochondrially encoded NADH dehydrogenase ND1 were not different between hMNs from WT and endstage SOD1G93A mice, these genes were used to normalize hMN-specific mRNA-levels of plasma membrane and mitochondrial Ca2+ transporters, respectively. We detected about 2-fold higher levels of the mitochondrial Ca2+ transporters MCU/MICU1, Letm1, and UCP2 in remaining hMNs from endstage SOD1G93A mice. These higher expression-levels of mitochondrial Ca2+ transporters in individual hMNs were not associated with a respective increase in number of mitochondrial genomes, as evident from hMN specific ND1 DNA quantification. Normalized mRNA-levels for the plasma membrane Na+/Ca2+ exchanger NCX1 were also about 2-fold higher in hMNs from SOD1G93A mice. Thus, pharmacological stimulation of Ca2+ transporters in highly vulnerable hMNs might offer a neuroprotective strategy for ALS.
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Affiliation(s)
- Tobias Mühling
- Department of Applied Physiology, Institute of Applied Physiology, Ulm University Ulm, Germany
| | - Johanna Duda
- Department of Applied Physiology, Institute of Applied Physiology, Ulm University Ulm, Germany
| | | | | | - Birgit Liss
- Department of Applied Physiology, Institute of Applied Physiology, Ulm University Ulm, Germany
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247
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Maury Y, Côme J, Piskorowski RA, Salah-Mohellibi N, Chevaleyre V, Peschanski M, Martinat C, Nedelec S. Combinatorial analysis of developmental cues efficiently converts human pluripotent stem cells into multiple neuronal subtypes. Nat Biotechnol 2014; 33:89-96. [PMID: 25383599 DOI: 10.1038/nbt.3049] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 09/19/2014] [Indexed: 12/19/2022]
Abstract
Specification of cell identity during development depends on exposure of cells to sequences of extrinsic cues delivered at precise times and concentrations. Identification of combinations of patterning molecules that control cell fate is essential for the effective use of human pluripotent stem cells (hPSCs) for basic and translational studies. Here we describe a scalable, automated approach to systematically test the combinatorial actions of small molecules for the targeted differentiation of hPSCs. Applied to the generation of neuronal subtypes, this analysis revealed an unappreciated role for canonical Wnt signaling in specifying motor neuron diversity from hPSCs and allowed us to define rapid (14 days), efficient procedures to generate spinal and cranial motor neurons as well as spinal interneurons and sensory neurons. Our systematic approach to improving hPSC-targeted differentiation should facilitate disease modeling studies and drug screening assays.
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Affiliation(s)
- Yves Maury
- CECS, I-STEM (Institute for Stem Cell Therapy and Exploration of Monogenic Diseases), AFM, Evry, France
| | - Julien Côme
- CECS, I-STEM (Institute for Stem Cell Therapy and Exploration of Monogenic Diseases), AFM, Evry, France
| | | | | | - Vivien Chevaleyre
- CNRS UMR 8118, Université Paris Descartes Sorbonne Paris Cité, Paris, France
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248
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Zhang Y, Lin S, Karakatsani A, Rüegg MA, Kröger S. Differential regulation of AChR clustering in the polar and equatorial region of murine muscle spindles. Eur J Neurosci 2014; 41:69-78. [PMID: 25377642 DOI: 10.1111/ejn.12768] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 09/29/2014] [Accepted: 10/02/2014] [Indexed: 12/16/2022]
Abstract
Intrafusal fibers of muscle spindles are innervated in the central region by afferent sensory axons and at both polar regions by efferent γ-motoneurons. We previously demonstrated that both neuron-muscle contact sites contain cholinergic synapse-like specialisation, including aggregates of the nicotinic acetylcholine receptor (AChR). In this study we tested the hypothesis that agrin and its receptor complex (consisting of LRP4 and the tyrosine kinase MuSK) are involved in the aggregation of AChRs in muscle spindles, similar to their role at the neuromuscular junction. We show that agrin, MuSK and LRP4 are concentrated at the contact site between the intrafusal fibers and the sensory- and γ-motoneuron, respectively, and that they are expressed in the cell bodies of proprioceptive neurons in dorsal root ganglia. Moreover, agrin and LRP4, but not MuSK, are expressed in γ-motoneuron cell bodies in the ventral horn of the spinal cord. In agrin- and in MuSK-deficient mice, AChR aggregates are absent from the polar regions. In contrast, the subcellular concentration of AChRs in the central region where the sensory neuron contacts the intrafusal muscle fiber is apparently unaffected. Skeletal muscle-specific expression of miniagrin in agrin(-/-) mice in vivo is sufficient to restore the formation of γ-motoneuron endplates. These results show that agrin and MuSK are major determinants during the formation of γ-motoneuron endplates but appear dispensable for the aggregation of AChRs at the central region. Our results therefore suggest different molecular mechanisms for AChR clustering within two domains of intrafusal fibers.
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Affiliation(s)
- Yina Zhang
- Department of Physiological Genomics, Ludwig-Maximilians-University, Pettenkoferstrasse 12, D-80336, Munich, Germany; Helmholtz Center Munich, Neuherberg, Germany
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249
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Neurotrophic requirements of human motor neurons defined using amplified and purified stem cell-derived cultures. PLoS One 2014; 9:e110324. [PMID: 25337699 PMCID: PMC4206291 DOI: 10.1371/journal.pone.0110324] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 09/18/2014] [Indexed: 12/29/2022] Open
Abstract
Human motor neurons derived from embryonic and induced pluripotent stem cells (hESCs and hiPSCs) are a potentially important tool for studying motor neuron survival and pathological cell death. However, their basic survival requirements remain poorly characterized. Here, we sought to optimize a robust survival assay and characterize their response to different neurotrophic factors. First, to increase motor neuron yield, we screened a small-molecule collection and found that the Rho-associated kinase (ROCK) inhibitor Y-27632 enhances motor neuron progenitor proliferation up to 4-fold in hESC and hiPSC cultures. Next, we FACS-purified motor neurons expressing the Hb9::GFP reporter from Y-27632-amplified embryoid bodies and cultured them in the presence of mitotic inhibitors to eliminate dividing progenitors. Survival of these purified motor neurons in the absence of any other cell type was strongly dependent on neurotrophic support. GDNF, BDNF and CNTF all showed potent survival effects (EC(50) 1-2 pM). The number of surviving motor neurons was further enhanced in the presence of forskolin and IBMX, agents that increase endogenous cAMP levels. As a demonstration of the ability of the assay to detect novel neurotrophic agents, Y-27632 itself was found to support human motor neuron survival. Thus, purified human stem cell-derived motor neurons show survival requirements similar to those of primary rodent motor neurons and can be used for rigorous cell-based screening.
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250
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Stifani N. Motor neurons and the generation of spinal motor neuron diversity. Front Cell Neurosci 2014; 8:293. [PMID: 25346659 PMCID: PMC4191298 DOI: 10.3389/fncel.2014.00293] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 09/02/2014] [Indexed: 11/13/2022] Open
Abstract
Motor neurons (MNs) are neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets. This function infers the existence of MN subtypes matching the identity of the targets they innervate. To illustrate the mechanism involved in the generation of cellular diversity and the acquisition of specific identity, this review will focus on spinal MNs (SpMNs) that have been the core of significant work and discoveries during the last decades. SpMNs are responsible for the contraction of effector muscles in the periphery. Humans possess more than 500 different skeletal muscles capable to work in a precise time and space coordination to generate complex movements such as walking or grasping. To ensure such refined coordination, SpMNs must retain the identity of the muscle they innervate. Within the last two decades, scientists around the world have produced considerable efforts to elucidate several critical steps of SpMNs differentiation. During development, SpMNs emerge from dividing progenitor cells located in the medial portion of the ventral neural tube. MN identities are established by patterning cues working in cooperation with intrinsic sets of transcription factors. As the embryo develop, MNs further differentiate in a stepwise manner to form compact anatomical groups termed pools connecting to a unique muscle target. MN pools are not homogeneous and comprise subtypes according to the muscle fibers they innervate. This article aims to provide a global view of MN classification as well as an up-to-date review of the molecular mechanisms involved in the generation of SpMN diversity. Remaining conundrums will be discussed since a complete understanding of those mechanisms constitutes the foundation required for the elaboration of prospective MN regeneration therapies.
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Affiliation(s)
- Nicolas Stifani
- Medical Neuroscience, Dalhousie University Halifax, NS, Canada
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