951
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Johansson A, Engler H, Blomquist G, Scott B, Wall A, Aquilonius SM, Långström B, Askmark H. Evidence for astrocytosis in ALS demonstrated by [11C](L)-deprenyl-D2 PET. J Neurol Sci 2007; 255:17-22. [PMID: 17346749 DOI: 10.1016/j.jns.2007.01.057] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 01/19/2007] [Accepted: 01/23/2007] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To use deuterium-substituted [11C](L)-deprenyl PET to depict astrocytosis in vivo in patients with amyotrophic lateral sclerosis (ALS). BACKGROUND In human brain, the enzyme MAO-B is primarily located in astrocytes. L-deprenyl binds to MAO-B and autoradiography with 3H-L-deprenyl has been used to map astrocytosis in vitro. Motor neuron loss in ALS is accompanied by astrocytosis and astrocytes may play an active role in the neurodegenerative process. Deuterium-substituted [11C](L)-deprenyl PET provides an opportunity to localize astrocytosis in vivo in the brain of patients with ALS. METHODS Deuterium-substituted [11C](L)-deprenyl PET was performed in seven patients with ALS and seven healthy control subjects. RESULTS Increased uptake rate of [11C](L)-deprenyl was demonstrated in ALS in pons and white matter. CONCLUSION This study provides evidence that astrocytosis may be detected in vivo in ALS by the use of deuterium-substituted [11C](L)-deprenyl PET though further studies are needed to determine whether deuterium-substituted [11C](L)-deprenyl binding tracks disease progression and reflects astrocytosis.
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Affiliation(s)
- Anders Johansson
- Department of Neurology, University Hospital, S-751 85 Uppsala, Sweden.
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952
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Conforti L, Adalbert R, Coleman MP. Neuronal death: where does the end begin? Trends Neurosci 2007; 30:159-66. [PMID: 17339056 DOI: 10.1016/j.tins.2007.02.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 01/22/2007] [Accepted: 02/19/2007] [Indexed: 11/21/2022]
Abstract
Neurodegenerative disorders involve death of cell bodies, axons, dendrites and synapses, but it is surprisingly difficult to determine the spatiotemporal sequence of events and the causal relationships among these events. Neuronal compartments often crucially depend upon one another for survival, and molecular defects in one compartment can trigger cellular degeneration in distant parts of the neuron. Here, we consider the novel approaches used to understand these biologically complex and technically challenging questions in amyotrophic lateral sclerosis, spinal muscular atrophy, glaucoma, Alzheimer's disease, Parkinson's disease and polyglutamine disorders. We conclude that there is partial understanding of what degenerates first and why, but that controversy remains the rule not the exception. Finally, we highlight strategies for resolving these fundamental issues.
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Affiliation(s)
- Laura Conforti
- The Babraham Institute, Babraham, Cambridge CB22 3AT, UK
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953
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Martin LJ, Liu Z, Chen K, Price AC, Pan Y, Swaby JA, Golden WC. Motor neuron degeneration in amyotrophic lateral sclerosis mutant superoxide dismutase-1 transgenic mice: mechanisms of mitochondriopathy and cell death. J Comp Neurol 2007; 500:20-46. [PMID: 17099894 DOI: 10.1002/cne.21160] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mechanisms of human mutant superoxide dismutase-1 (mSOD1) toxicity to motor neurons (MNs) are unresolved. We show that MNs in G93A-mSOD1 transgenic mice undergo slow degeneration lacking similarity to apoptosis structurally and biochemically. It is characterized by somal and mitochondrial swelling and formation of DNA single-strand breaks prior to double-strand breaks occurring in nuclear and mitochondrial DNA. p53 and p73 are activated in degenerating MNs, but without nuclear import. The MN death is independent of activation of caspases-1, -3, and -8 or apoptosis-inducing factor within MNs, with a blockade of apoptosis possibly mediated by Aven up-regulation. MN swelling is associated with compromised Na,K-ATPase activity and aggregation. mSOD1 mouse MNs accumulate mitochondria from the axon terminals and generate higher levels of superoxide, nitric oxide, and peroxynitrite than MNs in control mice. Nitrated and aggregated cytochrome c oxidase subunit-I and alpha-synuclein as well as nitrated SOD2 accumulate in mSOD1 mouse spinal cord. Mitochondria in mSOD1 mouse MNs accumulate NADPH diaphorase and inducible nitric oxide synthase (iNOS)-like immunoreactivity, and iNOS gene deletion extends significantly the life span of G93A-mSOD1 mice. Prior to MN loss, spinal interneurons degenerate. These results identify novel mechanisms for mitochondriopathy and MN degeneration in amyotrophic lateral sclerosis (ALS) mice involving blockade of apoptosis, accumulation of MN mitochondria with enhanced toxic potential from distal terminals, NOS localization in MN mitochondria and peroxynitrite damage, and early degeneration of alpha-synuclein(+) interneurons. The data support roles for oxidative stress, protein nitration and aggregation, and excitotoxicity as participants in the process of MN degeneration caused by mSOD1.
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Affiliation(s)
- Lee J Martin
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA.
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954
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Gonzalez de Aguilar JL, Echaniz-Laguna A, Fergani A, René F, Meininger V, Loeffler JP, Dupuis L. Amyotrophic lateral sclerosis: all roads lead to Rome. J Neurochem 2007; 101:1153-60. [PMID: 17250677 DOI: 10.1111/j.1471-4159.2006.04408.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is the most frequent adult-onset motor neuron disease characterized by degeneration of upper and lower motor neurons, generalized weakness and muscle atrophy. Most cases of ALS appear sporadically but some forms of the disease result from mutations in the gene encoding the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1). Several other mutated genes have also been found to predispose to ALS including, among others, one that encodes the regulator of axonal retrograde transport dynactin. As all roads lead to the proverbial Rome, we discuss here how distinct molecular pathways may converge to the same final result that is motor neuron death. We critically review the basic research on SOD1-linked ALS to propose a pioneering model of a 'systemic' form of the disease, causally involving multiple cell types, either neuronal or non-neuronal. Contrasting this, we also postulate that other neuron-specific defects, as those triggered by dynactin dysfunction, may account for a primary motor neuron disease that would represent 'pure' neuronal forms of ALS. Identifying different disease subtypes is an unavoidable step toward the understanding of the physiopathology of ALS and will hopefully help to design specific treatments for each subset of patients.
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Affiliation(s)
- Jose-Luis Gonzalez de Aguilar
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, Université Louis Pasteur, Faculté de Médecine, UMRS692, Strasbourg, France
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955
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Li J, Bai Y, Ianakova E, Grandis M, Uchwat F, Trostinskaia A, Krajewski KM, Garbern J, Kupsky WJ, Shy ME. Major myelin protein gene (P0) mutation causes a novel form of axonal degeneration. J Comp Neurol 2007; 498:252-65. [PMID: 16856127 DOI: 10.1002/cne.21051] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutations in the major peripheral nervous system (PNS) myelin protein, myelin protein zero (MPZ), cause Charcot-Marie-Tooth Disease type 1B (CMT1B), typically thought of as a demyelinating peripheral neuropathy. Certain MPZ mutations, however, cause adult onset neuropathy with minimal demyelination but pronounced axonal degeneration. Mechanism(s) for this phenotype are unknown. We performed an autopsy of a 73-year-old woman with a late-onset neuropathy caused by an H10P MPZ mutation whose nerve conduction studies suggested severe axonal loss but no demyelination. The autopsy demonstrated axonal loss and reorganization of the molecular architecture of the axolemma. Segmental demyelination was negligible. In addition, we identified focal nerve enlargements containing MPZ and ubiquitin either in the inner myelin intralaminar and/or periaxonal space that separates axons from myelinating Schwann cells. Taken together, these data confirmed that a mutation in MPZ can cause axonal neuropathy, in the absence of segmental demyelination, thus uncoupling the two pathological processes. More important, it also provided potential molecular mechanisms as to how the axonal degeneration occurred: either by disruption of glial-axon interaction by protein aggregates or by alterations in the molecular architecture of internodes and paranodes. This report represents the first study in which the molecular basis of axonal degeneration in the late-onset CMT1B has been explored in human tissue.
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Affiliation(s)
- Jun Li
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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956
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Ravula SK, Wang MS, McClain MA, Asress SA, Frazier B, Glass JD. Spatiotemporal localization of injury potentials in DRG neurons during vincristine-induced axonal degeneration. Neurosci Lett 2007; 415:34-9. [PMID: 17267126 PMCID: PMC2665290 DOI: 10.1016/j.neulet.2007.01.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 01/03/2007] [Indexed: 11/25/2022]
Abstract
The distal to proximal degeneration of axons, or "dying back" is a common pattern of neuropathology in many diseases of the PNS and CNS. A long-standing debate has centered on whether this pattern of neurodegeneration is due to an insult to the cell body or to the axon itself, although it is likely that mechanisms are different for specific disease entities. We have addressed this question in a model system of vincristine-induced axonal degeneration. Here, we created a novel experimental apparatus combining a microfluidic divider with a multielectrode array substrate to allow for independent monitoring of injury-induced electrical activity from dorsal root ganglion (DRG) cell bodies and axons while isolating them into their own culture microenvironments. At specified doses, exposure of the cell body to vincristine caused neither morphological neurodegeneration nor persistent hyperexcitability. In comparison, exposure of the distal axon to the same dose of vincristine first caused a decrease in the excitability of the axon and then axonal degeneration in a dying back pattern. Additionally, exposure of axons to vincristine caused an initial period of hyperexcitability in the cell bodies, suggesting that a signal is transmitted from the distal axon to the soma during the progression of vincristine-induced axonal degeneration. These data support the proposition that vincristine has a direct neurotoxic effect on the axon.
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Affiliation(s)
- Surendra K Ravula
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
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957
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David G, Nguyen K, Barrett EF. Early vulnerability to ischemia/reperfusion injury in motor terminals innervating fast muscles of SOD1-G93A mice. Exp Neurol 2007; 204:411-20. [PMID: 17292357 PMCID: PMC2097955 DOI: 10.1016/j.expneurol.2006.12.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 11/27/2006] [Accepted: 12/04/2006] [Indexed: 10/23/2022]
Abstract
In mouse models of familial amyotrophic lateral sclerosis (fALS), motor neurons are especially vulnerable to oxidative stresses in vitro. To determine whether this increased vulnerability also extends to motor nerve terminals in vivo, we assayed the effect of tourniquet-induced ischemia/reperfusion (I/R) injury on motor terminals innervating fast and slow hindlimb muscles in male G93A-SOD1 mice and their wild-type littermates. These mice also expressed yellow fluorescent protein (YFP) in motor neurons. We report that in SOD1-G93A/YFP mice the motor terminals innervating two predominantly fast muscles, extensor digitorum longus (EDL) and plantaris, were more vulnerable to I/R injury than motor terminals innervating the predominantly slow soleus muscle. The mean duration of EDL ischemia required to produce a 50% reduction in endplate innervation in SOD1-G93A/YFP mice was 26 min, compared to 45 min in YFP-only mice. The post-I/R destruction of EDL terminals in SOD1-G93A mice was rapid (<2 h) and was not duplicated by cutting the sciatic nerve at the tourniquet site. The increased sensitivity to I/R injury was evident in EDL muscles of SOD1-G93A/YFP mice as young as 31 days, well before the onset of motor neuron death at approximately 90 days. This early vulnerability to I/R injury may correlate with the finding (confirmed here) that in fALS mice motor nerve terminals innervating fast hindlimb muscles degenerate before those innervating slow muscles, at ages that precede motor neuron death. Early vulnerability of fast motor terminals to I/R injury thus may signal, and possibly contribute to, early events involved in motor neuron death.
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Affiliation(s)
- Gavriel David
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, USA.
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958
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Neusch C, Bähr M, Schneider-Gold C. Glia cells in amyotrophic lateral sclerosis: New clues to understanding an old disease? Muscle Nerve 2007; 35:712-24. [PMID: 17373702 DOI: 10.1002/mus.20768] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In classic neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), the pathogenic concept of a cell-autonomous disease of motor neurons has been challenged increasingly in recent years. Macro- and microglial cells have come to the forefront for their role in multistep degenerative processes in ALS and respective disease models. The activation of astroglial and microglial cells occurs early in the pathogenesis of the disease and seems to greatly influence disease onset and promotion. The role of oligodendrocytes and Schwann cells remains elusive. In this review we highlight the impact of nonneuronal cells in ALS pathology. We discuss diverse glial membrane proteins that are necessary to control neuronal activity and neuronal cell survival, and summarize the contribution of these proteins to motor neuron death in ALS. We also describe recently discovered glial mechanisms that promote motor neuron degeneration using state-of-the-art genetic mouse technology. Finally, we provide an outlook on the extent to which these new pathomechanistic insights may offer novel therapeutic approaches.
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Affiliation(s)
- Clemens Neusch
- Department of Neurology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
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959
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Casanovas A, Hernández S, Tarabal O, Rosselló J, Esquerda JE. Strong P2X4 purinergic receptor-like immunoreactivity is selectively associated with degenerating neurons in transgenic rodent models of amyotrophic lateral sclerosis. J Comp Neurol 2007; 506:75-92. [DOI: 10.1002/cne.21527] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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960
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Julien JP, Kriz J. Chapter 6 Animal models of motor neuron death. HANDBOOK OF CLINICAL NEUROLOGY 2007; 82:121-138. [PMID: 18808891 DOI: 10.1016/s0072-9752(07)80009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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961
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Miller TM, Kim SH, Yamanaka K, Hester M, Umapathi P, Arnson H, Rizo L, Mendell JR, Gage FH, Cleveland DW, Kaspar BK. Gene transfer demonstrates that muscle is not a primary target for non-cell-autonomous toxicity in familial amyotrophic lateral sclerosis. Proc Natl Acad Sci U S A 2006; 103:19546-51. [PMID: 17164329 PMCID: PMC1748262 DOI: 10.1073/pnas.0609411103] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, progressive paralysis arising from the premature death of motor neurons. An inherited form is caused by a dominant mutation in the ubiquitously expressed superoxide dismutase (SOD1). SOD1 mutant expression within motor neurons is a determinant of onset and early disease, and mutant accumulation within microglia accelerates disease progression. Muscle also is a likely primary source for toxicity, because retraction of motor axons from synaptic connections to muscle is among the earliest presymptomatic events. To test involvement of muscle in ALS, viral delivery of transcription-mediated siRNA is shown to suppress mutant SOD1 accumulation within muscle alone but to be insufficient to maintain grip strength, whereas delivery to both motor neurons and muscle is sufficient. Use of a deletable mutant gene to diminish mutant SOD1 from muscle did not affect onset or survival. Finally, follistatin expression encoded by adeno-associated virus chronically inhibited myostatin and produced sustained increases in muscle mass, myofiber number, and fiber diameter, but these increases did not affect survival. Thus, SOD1-mutant-mediated damage within muscles is not a significant contributor to non-cell-autonomous pathogenesis in ALS, and enhancing muscle mass and strength provides no benefit in slowing disease onset or progression.
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Affiliation(s)
- Timothy M. Miller
- *Ludwig Institute for Cancer Research, La Jolla, CA 92093
- Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093
| | - Soo H. Kim
- Ohio State University, Columbus, OH 43210
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Koji Yamanaka
- *Ludwig Institute for Cancer Research, La Jolla, CA 92093
| | - Mark Hester
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Priya Umapathi
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Hannah Arnson
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Liza Rizo
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Jerry R. Mendell
- Ohio State University, Columbus, OH 43210
- Columbus Children's Research Institute, Columbus, OH 43205; and
| | - Fred H. Gage
- The Salk Institute for Biological Studies, La Jolla, CA 92186
| | - Don W. Cleveland
- *Ludwig Institute for Cancer Research, La Jolla, CA 92093
- Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093
- To whom correspondence may be addressed. E-mail:
| | - Brian K. Kaspar
- Ohio State University, Columbus, OH 43210
- Columbus Children's Research Institute, Columbus, OH 43205; and
- **To whom correspondence may be addressed at:
Columbus Children's Research Institute, Ohio State University, 700 Children's Drive, WA 3022, Columbus, OH 43205. E-mail:
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962
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Abstract
Amyotrophic lateral sclerosis is a late-onset progressive neurodegenerative disease affecting motor neurons. The etiology of most ALS cases remains unknown, but 2% of instances are due to mutations in Cu/Zn superoxide dismutase (SOD1). Since sporadic and familial ALS affects the same neurons with similar pathology, it is hoped that therapies effective in mutant SOD1 models will translate to sporadic ALS. Mutant SOD1 induces non-cell-autonomous motor neuron killing by an unknown gain of toxicity. Selective vulnerability of motor neurons likely arises from a combination of several mechanisms, including protein misfolding, mitochondrial dysfunction, oxidative damage, defective axonal transport, excitotoxicity, insufficient growth factor signaling, and inflammation. Damage within motor neurons is enhanced by damage incurred by nonneuronal neighboring cells, via an inflammatory response that accelerates disease progression. These findings validate therapeutic approaches aimed at nonneuronal cells.
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Affiliation(s)
- Séverine Boillée
- Ludwig Institute for Cancer Research and Departments of Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093, USA
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963
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Seburn KL, Nangle LA, Cox GA, Schimmel P, Burgess RW. An active dominant mutation of glycyl-tRNA synthetase causes neuropathy in a Charcot-Marie-Tooth 2D mouse model. Neuron 2006; 51:715-26. [PMID: 16982418 DOI: 10.1016/j.neuron.2006.08.027] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 08/11/2006] [Accepted: 08/23/2006] [Indexed: 11/22/2022]
Abstract
Of the many inherited Charcot-Marie-Tooth peripheral neuropathies, type 2D (CMT2D) is caused by dominant point mutations in the gene GARS, encoding glycyl tRNA synthetase (GlyRS). Here we report a dominant mutation in Gars that causes neuropathy in the mouse. Importantly, both sensory and motor axons are affected, and the dominant phenotype is not caused by a loss of the GlyRS aminoacylation function. Mutant mice have abnormal neuromuscular junction morphology and impaired transmission, reduced nerve conduction velocities, and a loss of large-diameter peripheral axons, without defects in myelination. The mutant GlyRS enzyme retains aminoacylation activity, and a loss-of-function allele, generated by a gene-trap insertion, shows no dominant phenotype in mice. These results indicate that the CMT2D phenotype is caused not by reduction of the canonical GlyRS activity and insufficiencies in protein synthesis, but instead by novel pathogenic roles for the mutant GlyRS that specifically affect peripheral neurons.
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Affiliation(s)
- Kevin L Seburn
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
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964
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Chevalier-Larsen E, Holzbaur ELF. Axonal transport and neurodegenerative disease. Biochim Biophys Acta Mol Basis Dis 2006; 1762:1094-108. [PMID: 16730956 DOI: 10.1016/j.bbadis.2006.04.002] [Citation(s) in RCA: 317] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/24/2006] [Accepted: 04/11/2006] [Indexed: 01/12/2023]
Abstract
Neurons have extensive processes and communication between those processes and the cell body is crucial to neuronal function and survival. Thus, neurons are uniquely dependent on microtubule based transport. Growing evidence supports the idea that deficits in axonal transport contribute to pathogenesis in multiple neurodegenerative diseases. We describe the motor, cytoskeletal, and adaptor proteins involved in axonal transport and their interactions. Data linking disruption of axonal transport to diseases such as ALS are discussed. Finally, we explore the pathways that may cause neuronal dysfunction and death.
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965
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Hensley K, Mhatre M, Mou S, Pye QN, Stewart C, West M, Williamson KS. On the relation of oxidative stress to neuroinflammation: lessons learned from the G93A-SOD1 mouse model of amyotrophic lateral sclerosis. Antioxid Redox Signal 2006; 8:2075-87. [PMID: 17034351 DOI: 10.1089/ars.2006.8.2075] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The central nervous system (CNS) presents both challenges and opportunities to researchers of redox biochemistry. The CNS is sensitive to oxidative damage during aging or disease; excellent transgenic models of specific neurodegenerative diseases have been created that reproduce oxidative stress components of the corresponding human disorder. Mouse models of familial amyotrophic lateral sclerosis (ALS) based on overexpressed mutant human Cu, Zn-superoxide dismutase (SOD1) are cases in point. These animals experience predictably staged, age-dependent motor neuron degeneration with profound cellular and biochemical damage to nerve fibers and spinal cord tissue. Severe protein and lipid oxidation occurs in these animals, apparently as an indirect consequence of protein aggregation or cytopathic protein-protein interactions, as opposed to aberrant redox catalysis by the mutant enzyme. Recent studies of G93A-SOD1 mice and rats suggest that oxidative damage is part of an unmitigated neuroinflammatory reaction, possibly arising in combination from mitochondrial dysfunction plus pathophysiologic activation of both astrocytes and microglia. Lesions to redox signal-transduction pathways in mutant SOD1+ glial cells may stimulate broad-spectrum upregulation of proinflammatory genes, including arachidonic acid-metabolizing enzymes [e.g., cyclooxygenase-II (COX-II) and 5-lipoxygenase (5LOX)]; nitric oxide synthase (NOS) isoforms; cytokines (particularly tumor necrosis factor alpha, TNF-alpha); chemokines; and immunoglobulin Fc receptors (FcgammaRs). The integration of these processes creates a paracrine milieu inconsistent with healthy neural function. This review summarizes what has been learned to date from studies of mutant SOD1 transgenic animals and demonstrates that the G93A-SOD1 mouse in particular is a robust laboratory for the study of neuroinflammation and redox biochemistry.
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Affiliation(s)
- Kenneth Hensley
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland, USA.
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966
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Jokic N, Gonzalez de Aguilar JL, Dimou L, Lin S, Fergani A, Ruegg MA, Schwab ME, Dupuis L, Loeffler JP. The neurite outgrowth inhibitor Nogo-A promotes denervation in an amyotrophic lateral sclerosis model. EMBO Rep 2006; 7:1162-7. [PMID: 17039253 PMCID: PMC1679784 DOI: 10.1038/sj.embor.7400826] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 09/01/2006] [Accepted: 09/01/2006] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron loss and muscle wasting. In muscles of ALS patients, Nogo-A-a protein known to inhibit axon regeneration-is ectopically expressed at levels that correlate with the severity of the clinical symptoms. We now show that the genetic ablation of Nogo-A extends survival and reduces muscle denervation in a mouse model of ALS. In turn, overexpression of Nogo-A in wild-type muscle fibres leads to shrinkage of the postsynapse and retraction of the presynaptic motor ending. This suggests that the expression of Nogo-A occurring early in ALS skeletal muscle could cause repulsion and destabilization of the motor nerve terminals, and subsequent dying back of the axons and motor neurons.
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Affiliation(s)
- Natasa Jokic
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, 11 rue Humann, F-67085 Strasbourg, France
- Université Louis Pasteur, Faculté de Médecine, UMRS692, 11 rue Humann, F-67085 Strasbourg, France
| | - Jose-Luis Gonzalez de Aguilar
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, 11 rue Humann, F-67085 Strasbourg, France
- Université Louis Pasteur, Faculté de Médecine, UMRS692, 11 rue Humann, F-67085 Strasbourg, France
| | - Leda Dimou
- Brain Research Institute, University of Zurich and Department of Biology, ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Shuo Lin
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Anissa Fergani
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, 11 rue Humann, F-67085 Strasbourg, France
- Université Louis Pasteur, Faculté de Médecine, UMRS692, 11 rue Humann, F-67085 Strasbourg, France
| | - Markus A Ruegg
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Martin E Schwab
- Brain Research Institute, University of Zurich and Department of Biology, ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Luc Dupuis
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, 11 rue Humann, F-67085 Strasbourg, France
- Université Louis Pasteur, Faculté de Médecine, UMRS692, 11 rue Humann, F-67085 Strasbourg, France
| | - Jean-Philippe Loeffler
- Inserm, U692, Laboratoire de Signalisations Moléculaires et Neurodégénérescence, 11 rue Humann, F-67085 Strasbourg, France
- Université Louis Pasteur, Faculté de Médecine, UMRS692, 11 rue Humann, F-67085 Strasbourg, France
- Tel: +33 390 24 30 81; Fax: +33 390 24 30 65; E-mail:
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967
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Canh MY, Serpe CJ, Sanders V, Jones KJ. CD4(+) T cell-mediated facial motoneuron survival after injury: Distribution pattern of cell death and rescue throughout the extent of the facial motor nucleus. J Neuroimmunol 2006; 181:93-9. [PMID: 17045343 DOI: 10.1016/j.jneuroim.2006.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 08/02/2006] [Accepted: 08/14/2006] [Indexed: 11/24/2022]
Abstract
We have previously demonstrated that CD4(+) T cells transiently rescue facial motoneurons (FMN) from axotomy-induced death in immunodeficient mice. Three subpopulations of motoneurons have been observed within the facial motor nucleus following axotomy: one that always survives axotomy (50%), one that is amenable to rescue from axotomy-induced death through the addition of neurotrophic factors or CD4(+) T cells (30-40%), and one that always dies after axotomy (10-15%). The objective of this study was to anatomically map the extent of axotomy-induced cell death and immune cell rescue in the facial nucleus to study the differential survival capabilities of each subpopulation. Wild-type (WT) mice, recombinase activating gene 2 knockout (RAG-2 KO) mice, and RAG-2 KO mice reconstituted with CD4(+) T cells were subjected to right facial nerve axotomy. At 4 weeks post-axotomy, topographical mapping of axotomy-induced cell death throughout the rostro-caudal extent of the facial nucleus was accomplished in accordance with previously published maps of the subnuclear arrangement of the facial neurons. The results indicate that all 3 subpopulations of FMN can be found in each of the subnuclear groups throughout the entire rostro-caudal extent of the facial nucleus. These data are discussed in context of recent work in amyotrophic lateral sclerosis, a fatal motoneuron disease.
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Affiliation(s)
- Minh-Y Canh
- Department of Cell Biology, Neurobiology and Anatomy Loyola University Chicago, Maywood, IL 60153, USA
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968
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Li W, Brakefield D, Pan Y, Hunter D, Myckatyn TM, Parsadanian A. Muscle-derived but not centrally derived transgene GDNF is neuroprotective in G93A-SOD1 mouse model of ALS. Exp Neurol 2006; 203:457-71. [PMID: 17034790 DOI: 10.1016/j.expneurol.2006.08.028] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 07/27/2006] [Accepted: 08/29/2006] [Indexed: 12/13/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for motoneurons (MNs), and is considered a potential agent for the treatment of amyotrophic lateral sclerosis (ALS) and other MN diseases. The effectiveness of GDNF may depend significantly upon its route of delivery to MNs. In this study we tested the neuroprotective effects of target-derived and centrally derived GDNF in the G93A-SOD1 mouse model of ALS using a transgenic approach. We found that overexpression of GDNF in the skeletal muscle (Myo-GDNF mice) significantly delayed the onset of disease and increased the life span of G93A-SOD1 mice by 17 days. The duration of disease also increased by 8.5 days, indicating that GDNF slowed down the progression of disease. Locomotor performance in Myo-GDNF/G93A-SOD1 mice was also significantly improved. The behavioral improvement correlated well with anatomical and histological data. We demonstrated that muscle-derived GDNF resulted in increased survival of spinal MNs, and twice as many MNs survived in end-stage double transgenic mice compared to end-stage G93A-SOD1 mice. Muscle-derived GDNF also had profound effects on muscle innervation and axonal degeneration. Significantly higher numbers of completely or partially innervated NMJs and large caliber myelinated axons were found in double transgenic mice. In contrast, we demonstrated that overexpression of GDNF in astrocytes in the CNS (GFAP-GDNF mice) failed to demonstrate any neuroprotective effects in G93A-SOD1 mice both on behavioral and histological levels. These data indicate that retrograde transport and signaling of GDNF is more physiological and effective for ALS treatment than anterogradely transported GDNF.
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Affiliation(s)
- Wen Li
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, Box 8518, St. Louis, MO 63110, USA
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969
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Adalbert R, Nógrádi A, Szabó A, Coleman MP. The slow Wallerian degeneration genein vivoprotects motor axons but not their cell bodies after avulsion and neonatal axotomy. Eur J Neurosci 2006; 24:2163-8. [PMID: 17074042 DOI: 10.1111/j.1460-9568.2006.05103.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The slow Wallerian degeneration gene (Wld(S)) delays Wallerian degeneration and axon pathology for several weeks in mice and rats. Interestingly, neuronal cell death is also delayed in some in vivo models, most strikingly in the progressive motoneuronopathy mouse. Here, we tested the hypothesis that Wld(S) has a direct protective effect on motoneurone cell bodies in vivo. Cell death was induced in rat L4 motoneurones by intravertebral avulsion of the corresponding ventral roots. This simultaneously removed most of the motor axon, minimizing the possibility that the protective effect toward axons could rescue cell bodies secondarily. There was no significant difference between the survival of motoneurones in control and Wld(S) rats, suggesting that the Wld(S) gene has no direct protective effect on cell bodies. We also tested for any delay in apoptotic motoneurone death following neonatal nerve injury in Wld(S) rats and found that, unlike Wld(S) mice, Wld(S) rats show no delay in cell death. However, the corresponding distal axons were preserved, confirming that motoneurone cell bodies and motor axons die by different mechanisms. Thus, Wld(S) does not directly prevent death of motoneurone cell bodies. It follows that the protection of neuronal cell bodies observed in several disease and injury models where axons or significant axonal stumps remain is most probably secondary to axonal protection.
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970
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Zhang J, Huang EJ. Dynamic expression of neurotrophic factor receptors in postnatal spinal motoneurons and in mouse model of ALS. ACTA ACUST UNITED AC 2006; 66:882-95. [PMID: 16680759 PMCID: PMC3600432 DOI: 10.1002/neu.20269] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neurotrophic factors support the survival of spinal motoneurons (MNs) and have been considered as strong candidates for treating motoneuron diseases. However, it is unclear if the right combination of neurotrophic factor receptors is present in postnatal spinal MNs. In this study, we show that the level of c-ret expression remains relatively stable in embryonic and postnatal spinal MNs. In contrast, the mRNA and protein of GFRalpha1 and -2 are progressively down-regulated in postnatal life. By 3 and 6 months of age, both receptors are barely detectable in spinal MNs. The down-regulation of GFRalpha1 appears accelerated in transgenic mice expressing mutant SOD1(G93A). Despite the progressive loss of GFRalpha1 and -2, phosphorylation of c-ret shows no detectable reduction on tyrosine residues or on serine 696. In addition to the GFRalpha subunits, expression of TrkB also shows a dynamic change. During embryogenesis, there is twice as much full-length TrkB as the truncated TrkB isoform. However, this ratio is reversed in postnatal spinal cord. Expression of the mutant SOD1(G93A) appears to have no effect on the TrkB receptor ratio. Taken together, our data indicate that the expression of neurotrophic factor receptors, GFRalpha1, -2, and TrkB, is not static, but undergoes dynamic changes in postnatal spinal MNs. These results provide insights into the use of neurotrophic factors as therapeutic agents for ALS.
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Affiliation(s)
- Jiasheng Zhang
- Department of Pathology, University of California San Francisco and Pathology, Service 113B, VA Medical Center, 94121, USA
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971
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Dupuis L, Gonzalez de Aguilar JL, Echaniz-Laguna A, Loeffler JP. Mitochondrial dysfunction in amyotrophic lateral sclerosis also affects skeletal muscle. Muscle Nerve 2006; 34:253-4. [PMID: 16642501 DOI: 10.1002/mus.20566] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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972
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Gould TW, Buss RR, Vinsant S, Prevette D, Sun W, Knudson CM, Milligan CE, Oppenheim RW. Complete dissociation of motor neuron death from motor dysfunction by Bax deletion in a mouse model of ALS. J Neurosci 2006; 26:8774-86. [PMID: 16928866 PMCID: PMC6674380 DOI: 10.1523/jneurosci.2315-06.2006] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 06/30/2006] [Accepted: 07/06/2006] [Indexed: 11/21/2022] Open
Abstract
The death of cranial and spinal motoneurons (MNs) is believed to be an essential component of the pathogenesis of amyotrophic lateral sclerosis (ALS). We tested this hypothesis by crossing Bax-deficient mice with mice expressing mutant superoxide dismutase 1 (SOD1), a transgenic model of familial ALS. Although Bax deletion failed to prevent neuromuscular denervation and mitochondrial vacuolization, MNs were completely rescued from mutant SOD1-mediated death. However, Bax deficiency extended lifespan and delayed the onset of motor dysfunction of SOD1 mutants, suggesting that Bax acts via a mechanism distinct from cell death activation. Consistent with this idea, Bax elimination delayed the onset of neuromuscular denervation, which began long before the activation of cell death proteins in SOD1 mutants. Additionally, we show that denervation preceded accumulation of mutant SOD1 within MNs and astrogliosis in the spinal cord, which are also both delayed in Bax-deficient SOD1 mutants. Interestingly, MNs exhibited mitochondrial abnormalities at the innervated neuromuscular junction at the onset of neuromuscular denervation. Additionally, both MN presynaptic terminals and terminal Schwann cells expressed high levels of mutant SOD1 before MNs withdrew their axons. Together, these data support the idea that clinical symptoms in the SOD1 G93A model of ALS result specifically from damage to the distal motor axon and not from activation of the death pathway, and cast doubt on the utility of anti-apoptotic therapies to combat ALS. Furthermore, they suggest a novel, cell death-independent role for Bax in facilitating mutant SOD1-mediated motor denervation.
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Affiliation(s)
- Thomas W. Gould
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
| | - Robert R. Buss
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
| | - Sharon Vinsant
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
| | - David Prevette
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
| | - Woong Sun
- Department of Anatomy, College of Medicine, Brain Korea 21, Korea University, Sungbuk-Gu, Seoul 136-705, Korea, and
| | - C. Michael Knudson
- Department of Pathology, The University of Iowa Roy J. and Lucille P. Carver College of Medicine, Iowa City, Iowa 52242
| | - Carol E. Milligan
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
| | - Ronald W. Oppenheim
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University, Winston-Salem, North Carolina 27157-1010
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973
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Abramow-Newerly W, Lipina T, Abramow-Newerly M, Kim D, Bechard AR, Xie G, Clapcote SJ, Roder JC. Methods to rapidly and accurately screen a large number of ENU mutagenized mice for abnormal motor phenotypes. ACTA ACUST UNITED AC 2006; 7:112-8. [PMID: 16753976 DOI: 10.1080/14660820500443000] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In a dominant genetic screen for late-onset motor impairments in mice, 16-20-week-old N-nitroso-N-ethylurea (ENU)-mutagenized females were subjected to a behavioural test battery consisting of a visual assessment followed by the vertical pole, rotarod and grip strength tests. SOD1-G93A transgenic mice were tested in parallel as a positive control to provide information on the validity and sensitivity of the screen. From among the 1500 G1 ENU mice screened, four affected mice with impaired motor function were classified as outliers. Approximately 32% of the G2 and G3 progeny of one outlier were affected. Vertical pole, rotarod and grip strength test scores were significantly correlated with each other and with body weight in the G1 progeny, but the correlation with body weight was not maintained in the G2 and G3 progeny. We found that two tests, tail suspension and vertical pole, were sufficient to distinguish ENU outliers and SOD1-G93A hemizygotes from control mice, and could detect abnormalities earlier and more frequently than the other tests employed.
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Affiliation(s)
- Wanda Abramow-Newerly
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.
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974
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Liu Z, Martin LJ. The adult neural stem and progenitor cell niche is altered in amyotrophic lateral sclerosis mouse brain. J Comp Neurol 2006; 497:468-88. [PMID: 16736475 DOI: 10.1002/cne.21012] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal adult human disease caused by motor neuron degeneration. Stem cell therapy might be a treatment for ALS. The adult mammalian forebrain has neural stem cells (NSCs) and neural progenitor cells (NPCs) in the anterior subventricular zone (SVZa), rostral migratory stream (RMS), olfactory bulb (OB) core, and dentate gyrus (DG). These cells could be used to rescue or replace degenerating upper and lower motor neurons through endogenous recruitment or autologous/allogenic transplantation. We evaluated the competency of forebrain NSCs and NPCs in transgenic (tg) mice harboring human mutant superoxide dismutase-1 (mSOD1), a model of ALS. Tg human wild-type SOD1 (wtSOD1) mice and non-tg mice were controls. Bromodeoxyuridine (BrdU) labeling of cells, a marker for cell proliferation and other events, was reduced in a niche-specific pattern in presymptomatic and symptomatic mice, with the SVZa having greater reductions than the RMS, OB, and DG. Different NSC and NPC complements were evaluated by localizing nestin, neural cell adhesion molecule, distalless-2 transcription factor, vimentin, and glial fibrillary acidic protein. In symptomatic mice, NSC markers were reduced, whereas NPC markers were unchanged or elevated. Neurogenesis was preserved in symptomatic mSOD1 mice. NSC/NPC competence assessment in vitro revealed that mSOD1 SVZa cells had the ability to proliferate and form neurospheres but had an impaired response to mitogen stimulation. We conclude that adult mSOD1 ALS mice have abnormalities in forebrain NSCs, but the essential features of NSC/NPCs remained in presymptomatic and symptomatic mice.
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Affiliation(s)
- Zhiping Liu
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA
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975
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Abstract
Recent developments in our understanding of the pathophysiological mechanisms underlying degeneration in both the central and peripheral nervous systems have highlighted the critical role that synapses play in the instigation and progression of neuronal loss. In fact, several lines of evidence suggest that previous attempts to delay the onset and progression of clinical symptoms in a broad range of neurodegenerative diseases may have been unsuccessful as a result of a failure to protect synaptic compartments. As a result, the synapse needs to be viewed as an important target for the development of novel protective treatments aimed at preventing or slowing disease progression. We summarize important findings from human studies and animal models demonstrating common synaptic vulnerability across several neurodegenerative diseases. We also discuss recent developments in our understanding of degenerative mechanisms that are known to be localized to synapses and suggest potential ways to harness this understanding to develop synaptoprotective strategies for neurodegenerative disease.
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Affiliation(s)
- Thomas M Wishart
- Centre for Integrative Physiology & Centre for Neuroscience Research, University of Edinburgh Medical School, UK
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976
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Holzbaur ELF, Howland DS, Weber N, Wallace K, She Y, Kwak S, Tchistiakova LA, Murphy E, Hinson J, Karim R, Tan XY, Kelley P, McGill KC, Williams G, Hobbs C, Doherty P, Zaleska MM, Pangalos MN, Walsh FS. Myostatin inhibition slows muscle atrophy in rodent models of amyotrophic lateral sclerosis. Neurobiol Dis 2006; 23:697-707. [PMID: 16837207 DOI: 10.1016/j.nbd.2006.05.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 05/23/2006] [Accepted: 05/29/2006] [Indexed: 11/19/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease leading to motor neuron cell death, but recent studies suggest that non-neuronal cells may contribute to the pathological mechanisms involved. Myostatin is a negative regulator of muscle growth whose function can be inhibited using neutralizing antibodies. In this study, we used transgenic mouse and rat models of ALS to test whether treatment with anti-myostatin antibody slows muscle atrophy, motor neuron loss, or disease onset and progression. Significant increases in muscle mass and strength were observed in myostatin-antibody-treated SOD1(G93A) mice and rats prior to disease onset and during early-stage disease. By late stage disease, only diaphragm muscle remained significantly different in treated animals in comparison to untreated controls. Myostatin inhibition did not delay disease onset nor extend survival in either the SOD1(G93A) mouse or rat. Together, these results indicate that inhibition of myostatin does not protect against the onset and progression of motor neuron degenerative disease. However, the preservation of skeletal muscle during early-stage disease and improved diaphragm morphology and function maintained through late stage disease suggest that anti-myostatin therapy may promote some improved muscle function in ALS.
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Affiliation(s)
- Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania School of Medicine, D400 Richards Building, 3700 Hamilton Walk, Philadelphia, PA 19104-6085, USA.
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977
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Sumi H, Nagano S, Fujimura H, Kato S, Sakoda S. Inverse correlation between the formation of mitochondria-derived vacuoles and Lewy-body-like hyaline inclusions in G93A superoxide-dismutase-transgenic mice. Acta Neuropathol 2006; 112:52-63. [PMID: 16642310 DOI: 10.1007/s00401-006-0056-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 02/12/2006] [Accepted: 02/12/2006] [Indexed: 10/24/2022]
Abstract
In G93A mice, the most popular model of amyotrophic lateral sclerosis (ALS), neuronal Lewy-body-like hyaline inclusions (LBHIs) and mitochondria-derived vacuoles are observed in addition to motor neuron loss. Although LBHIs are thought to be toxic, the significance of the mitochondria-derived vacuoles has not been fully investigated. In this study, the relationship between the formation of these vacuoles and LBHIs was clarified statistically in the lumbar segment from two phyletic lines of G93A mice (G1L, G1H), using immunohistochemical methods. Furthermore, the distributions of vacuoles and LBHIs were examined in the pons including the facial nucleus, where pathological changes occur in ALS patients and G93A mice. Numerous vacuoles 2-3 microm in diameter were detected in the neuropil of the lumbar segment from G1L mice euthanatized approximately 3.5 months prior to the onset of the disease. Most of the vacuoles disappeared, but some became larger as the disease progressed. The number of vacuoles with a diameter exceeding 5 microm began to decrease after disease onset, while that of intra-neuritic LBHIs increased rapidly. There was a strong inverse correlation between the numbers of vacuoles and LBHIs in symptomatic mice (P<0.01; G1L, r=-0.91; G1H, r=-0.93). In the facial nucleus of G1L mice, where the number of motor neurons was significantly reduced, only a few LBHIs were detected along with prominent vacuole formation. In contrast, significantly more LBHIs with little vacuole formation were evident around the facial nucleus in G1L mice. Furthermore, the SOD1 immunoreactivity in vacuoles initially increased and then decreased after disease onset. Taken together, the present findings suggest that the mitochondria-derived vacuoles might prevent the formation of LBHIs by sequestering mutated SOD1 from the cytoplasm.
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Affiliation(s)
- Hisae Sumi
- Department of Neurology D-4, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita, 565-0871, Osaka, Japan.
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978
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Nakata M, Kuwabara S, Kanai K, Misawa S, Tamura N, Sawai S, Hattori T, Bostock H. Distal excitability changes in motor axons in amyotrophic lateral sclerosis. Clin Neurophysiol 2006; 117:1444-8. [PMID: 16765084 DOI: 10.1016/j.clinph.2006.04.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 03/24/2006] [Accepted: 04/07/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Previous axonal excitability studies in amyotrophic lateral sclerosis (ALS) have suggested that impaired potassium channel function could be responsible for the generation of fasciculations, but the ectopic activity arises predominantly from the motor nerve terminals. This study tested the hypothesis that dysfunction of potassium channels is more pronounced in the more distal parts of axons. METHODS Threshold electrotonus was used to compare accommodation at the motor point of abductor pollicis brevis, and at the wrist portion of the median nerve, between 22 patients with ALS and 19 normal subjects. As target responses for motor point stimulation, movement-related potentials were recorded using an accelerometer. RESULTS Compared to normal subjects, ALS patients showed greater threshold changes to depolarizing conditioning currents at both the motor point and wrist, suggesting less accommodation by potassium currents. Differences in the threshold electrotonus curves between the normal and ALS groups were much more prominent at the motor point than at the wrist. CONCLUSIONS In ALS, axonal potassium channels are impaired more prominently in distal portions of axons than at the nerve trunk, and this is consistent with evidence that fasciculations mostly arise from the nerve terminals. SIGNIFICANCE Excitability testing at the motor point provides additional information about the pathophysiology of ALS.
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Affiliation(s)
- Miho Nakata
- Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670, Japan.
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979
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Hervias I, Beal MF, Manfredi G. Mitochondrial dysfunction and amyotrophic lateral sclerosis. Muscle Nerve 2006; 33:598-608. [PMID: 16372325 DOI: 10.1002/mus.20489] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The causes of motor neuron death in amyotrophic lateral sclerosis (ALS) are still unknown. Several lines of evidence suggest that mitochondrial dysfunction may be involved in the pathogenesis of ALS. Biochemical and morphological mitochondrial abnormalities have been demonstrated in postmortem spinal cords of ALS patients. Furthermore, in transgenic mice expressing mutant Cu,Zn-superoxide dismutase (SOD1), the antioxidant enzyme associated with familial ALS (FALS), mitochondrial abnormalities precede the disease onset, suggesting that mitochondrial dysfunction is causally involved in the pathogenesis of SOD1-FALS. Despite this evidence, it is not yet fully understood how mutant SOD1 damages mitochondria. Recent work has demonstrated that a portion of mutant SOD1 is localized in mitochondria, both in transgenic mice and in FALS patients, where it forms proteinaceous aggregates. These findings have opened new avenues of investigation addressing the hypothesis that mutant SOD1 may directly damage mitochondria. Major future challenges will be to better understand the mechanisms and the consequences of mitochondrial dysfunction in ALS. If mitochondrial dysfunction is convincingly involved in ALS pathogenesis, either as a primary cause or as contributing factor, it is likely to become a novel target for therapeutic intervention.
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Affiliation(s)
- Isabel Hervias
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 525 East 68th Street, A-505, New York, New York 10021, USA
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980
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Ayala-Grosso C, Tam J, Roy S, Xanthoudakis S, Da Costa D, Nicholson DW, Robertson GS. Caspase-3 cleaved spectrin colocalizes with neurofilament-immunoreactive neurons in Alzheimer's disease. Neuroscience 2006; 141:863-874. [PMID: 16750894 DOI: 10.1016/j.neuroscience.2006.04.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2006] [Revised: 04/06/2006] [Accepted: 04/06/2006] [Indexed: 11/30/2022]
Abstract
Corticocortical disconnection in Alzheimer's disease occurs by the progressive impairment and eventual loss of a small subset of pyramidal neurons in layers III and V of association areas of the neocortex. These neurons exhibit large somatic size, extensive dendritic arborization and high levels of nonphosphorylated neurofilaments of medium and high molecular weight that can be identified using a monoclonal SMI-32 antibody. It is thought that the accumulation of amyloid Abeta and neurofibrillary tangles may provoke metabolic disturbances that result in the loss of these SMI-32 immunoreactive neurons. The recent detection of increased levels of caspase-3 cleaved fodrin in frontal, temporal and parietal association areas in Alzheimer's disease brains suggests that programmed cell death may contribute to the destruction of SMI-32 positive neurons. In the present study, we utilized an antibody that selectively recognizes the 120 kDa breakdown product of alphaIIspectrin (fodrin) generated by caspase-3 to determine whether this protease is activated in vulnerable pyramidal neurons located in layers III and V of Alzheimer's disease brains. Neurons immunoreactive for caspase-3 cleaved alphaIIspectrin were located predominantly in layers III and V of the inferior frontal and superior temporal cortices of patients with Alzheimer's disease but not age-matched controls. Pyramidal neurons immunoreactive for caspase-3 cleaved alphaIIspectrin invariably displayed SMI-32 immunoreactivity suggesting that caspase-3 activation is a pathological event that may be responsible for the loss of a subset of pyramidal neurons that comprise corticocortical projections.
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Affiliation(s)
- C Ayala-Grosso
- Unidad de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Nueva Granada, Apartado postal 40109, Caracas, Venezuela
| | - J Tam
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, C.P./P.O. Box 1005, Pointe Claire, Dorval, Quebec, Canada H9R 4P8
| | - S Roy
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, C.P./P.O. Box 1005, Pointe Claire, Dorval, Quebec, Canada H9R 4P8
| | - S Xanthoudakis
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, C.P./P.O. Box 1005, Pointe Claire, Dorval, Quebec, Canada H9R 4P8
| | - D Da Costa
- Unidad de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Nueva Granada, Apartado postal 40109, Caracas, Venezuela
| | - D W Nicholson
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, C.P./P.O. Box 1005, Pointe Claire, Dorval, Quebec, Canada H9R 4P8
| | - G S Robertson
- Departments of Psychiatry and Pharmacology, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, Nova Scotia, Canada B3H 1X5.
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981
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Abstract
Multiple techniques are available to study failure of neuromuscular transmission. Electrophysiological techniques used in patients are well suited to detect failure of neuromuscular transmission; however, these methods offer little insight into the mechanisms underlying failure of transmission. More detailed techniques that are better suited for studying the underlying mechanisms can be performed in animal models of neuromuscular disease. However, it is often difficult to compare studies using different techniques to measure neuromuscular transmission. In this review, I discuss different techniques that are available to study failure of neuromuscular transmission. The strengths and weaknesses of various techniques are compared using several diseases as examples. The review concludes with a discussion of mechanisms that may contribute to failure of neuromuscular transmission during repetitive stimulation.
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Affiliation(s)
- Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA.
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982
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Robay D, Patel H, Simpson MA, Brown NA, Crosby AH. Endogenous spartin, mutated in hereditary spastic paraplegia, has a complex subcellular localization suggesting diverse roles in neurons. Exp Cell Res 2006; 312:2764-77. [PMID: 16781711 DOI: 10.1016/j.yexcr.2006.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 05/03/2006] [Accepted: 05/05/2006] [Indexed: 11/28/2022]
Abstract
Mutation of spartin (SPG20) underlies a complicated form of hereditary spastic paraplegia, a disorder principally defined by the degeneration of upper motor neurons. Using a polyclonal antibody against spartin to gain insight into the function of the endogenous molecule, we show that the endogenous molecule is present in two main isoforms of 85 kDa and 100 kDa, and 75 kDa and 85 kDa in human and murine, respectively, with restricted subcellular localization. Immunohistochemical studies on human and mouse embryo sections and in vitro cell studies indicate that spartin is likely to possess both nuclear and cytoplasmic functions. The nuclear expression of spartin closely mirrors that of the snRNP (small nuclear ribonucleoprotein) marker alpha-Sm, a component of the spliceosome. Spartin is also enriched at the centrosome within mitotic structures. Notably we show that spartin protein undergoes dynamic positional changes in differentiating human SH-SY5Y cells. In undifferentiated non-neuronal cells, spartin displays a nuclear and diffuse cytosolic profile, whereas spartin transiently accumulates in the trans-Golgi network and subsequently decorates discrete puncta along neurites in terminally differentiated neuroblastic cells. Investigation of these spartin-positive vesicles reveals that a large proportion colocalizes with the synaptic vesicle marker synaptotagmin. Spartin is also enriched in synaptic-like structures and in synaptic vesicle-enriched fraction.
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Affiliation(s)
- Dimitri Robay
- Medical Genetics, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
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983
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De Winter F, Vo T, Stam FJ, Wisman LAB, Bär PR, Niclou SP, van Muiswinkel FL, Verhaagen J. The expression of the chemorepellent Semaphorin 3A is selectively induced in terminal Schwann cells of a subset of neuromuscular synapses that display limited anatomical plasticity and enhanced vulnerability in motor neuron disease. Mol Cell Neurosci 2006; 32:102-17. [PMID: 16677822 DOI: 10.1016/j.mcn.2006.03.002] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/09/2006] [Accepted: 03/13/2006] [Indexed: 01/28/2023] Open
Abstract
Neuromuscular synapses differ markedly in their plasticity. Motor nerve terminals innervating slow muscle fibers sprout vigorously following synaptic blockage, while those innervating fast-fatigable muscle fibers fail to exhibit any sprouting. Here, we show that the axon repellent Semaphorin 3A is differentially expressed in terminal Schwann cells (TSCs) on different populations of muscle fibers: postnatal, regenerative and paralysis induced remodeling of neuromuscular connections is accompanied by increased expression of Sema3A selectively in TSCs on fast-fatigable muscle fibers. To our knowledge, this is the first demonstration of a molecular difference between TSCs on neuromuscular junctions of different subtypes of muscle fibers. Interestingly, also in a mouse model for amyotrophic lateral sclerosis (ALS), Sema3A is expressed at NMJs of fast-fatigable muscle fibers. We propose that expression of Sema3A by TSCs not only suppresses nerve terminal plasticity at specific neuromuscular synapses, but may also contribute to their early and selective loss in the motor neuron disease ALS.
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Affiliation(s)
- Fred De Winter
- Graduate School for Neurosciences Amsterdam, Netherlands Institute for Brain Research, Meibergdreef 33, 1105 AZ Amsterdam, Netherlands
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984
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Conforti L, Fang G, Beirowski B, Wang MS, Sorci L, Asress S, Adalbert R, Silva A, Bridge K, Huang XP, Magni G, Glass JD, Coleman MP. NAD(+) and axon degeneration revisited: Nmnat1 cannot substitute for Wld(S) to delay Wallerian degeneration. Cell Death Differ 2006; 14:116-27. [PMID: 16645633 DOI: 10.1038/sj.cdd.4401944] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The slow Wallerian degeneration protein (Wld(S)), a fusion protein incorporating full-length nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1), delays axon degeneration caused by injury, toxins and genetic mutation. Nmnat1 overexpression is reported to protect axons in vitro, but its effect in vivo and its potency remain unclear. We generated Nmnat1-overexpressing transgenic mice whose Nmnat activities closely match that of Wld(S) mice. Nmnat1 overexpression in five lines of transgenic mice failed to delay Wallerian degeneration in transected sciatic nerves in contrast to Wld(S) mice where nearly all axons were protected. Transected neurites in Nmnat1 transgenic dorsal root ganglion explant cultures also degenerated rapidly. The delay in vincristine-induced neurite degeneration following lentiviral overexpression of Nmnat1 was significantly less potent than for Wld(S), and lentiviral overexpressed enzyme-dead Wld(S) still displayed residual neurite protection. Thus, Nmnat1 is significantly weaker than Wld(S) at protecting axons against traumatic or toxic injury in vitro, and has no detectable effect in vivo. The full protective effect of Wld(S) requires more N-terminal sequences of the protein.
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Affiliation(s)
- L Conforti
- The Babraham Institute, Cambridge CB2 4AT, UK
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985
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Julien JP, Kriz J. Transgenic mouse models of amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2006; 1762:1013-24. [PMID: 16675207 DOI: 10.1016/j.bbadis.2006.03.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 03/21/2006] [Accepted: 03/21/2006] [Indexed: 12/11/2022]
Abstract
The discovery of missense mutations in the gene coding for the Cu/Zn superoxide dismutase 1 (SOD1) in subsets of familial cases was rapidly followed by the generation of transgenic mice expressing various forms of SOD1 mutants. The mice overexpressing high levels of mutant SOD1 mRNAs do develop motor neuron disease but unraveling the mechanisms of pathogenesis has been very challenging. Studies with mouse lines suggest that the toxicity of mutant SOD1 is unrelated to copper-mediated catalysis but rather to propensity of a subfraction of mutant SOD1 proteins to form misfolded protein species and aggregates. However, the mechanism of toxicity of SOD1 mutants remains to be elucidated. Involvement of cytoskeletal components in ALS pathogenesis is supported by several mouse models of motor neuron disease with neurofilament abnormalities and with genetic defects in microtubule-based transport. Here, we describe how transgenic mouse models have been used for understanding pathogenic pathways of motor neuron disease and for pre-clinical drug testing.
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Affiliation(s)
- Jean-Pierre Julien
- Research Centre of CHUL, Department of Anatomy and Physiology of Laval University, 2705 Boulevard Laurier, Quebec, QC, Canada G1V 4G2.
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986
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de Burgos Lunar C, de Diego Villalón M, Moracho Sánchez J. Atrofia de la musculatura de la mano: a propósito de un caso. Semergen 2006. [DOI: 10.1016/s1138-3593(06)73253-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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987
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Teng YD, Choi H, Huang W, Onario RC, Frontera WR, Snyder EY, Sabharwal S. Therapeutic effects of clenbuterol in a murine model of amyotrophic lateral sclerosis. Neurosci Lett 2006; 397:155-8. [PMID: 16388902 DOI: 10.1016/j.neulet.2005.12.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 12/03/2005] [Accepted: 12/05/2005] [Indexed: 10/25/2022]
Abstract
We investigated the effects of clenbuterol, a beta2-adrenoceptor agonist with known anabolic and neuroprotective properties, on G93A-SOD1 mice, a transgenic murine model of familial amyotrophic lateral sclerosis (ALS). Relative to saline-treated vehicle controls (0.2 ml/kg/day; i.p.), early pathologic G93A-SOD1 mice treated with clenbuterol (1.5 mg/kg/day; i.p.) demonstrated a delayed onset of hindlimb signs as measured by rotarod performance, slowed disease progression, as well as trends toward mitigated losses of lumbar motoneurons and body weight. Responses in female G93A-SOD1 mice were favorable to those of males, suggesting synergistic effects between clenbuterol and sex-specific factors. Overall, our data suggest that clenbuterol offers therapeutic effects on ALS-related neuromuscular degeneration.
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Affiliation(s)
- Yang D Teng
- Department of Neurosurgery, Harvard Medical School/Children's Hospital Boston, MA, USA.
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988
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Raoul C, Buhler E, Sadeghi C, Jacquier A, Aebischer P, Pettmann B, Henderson CE, Haase G. Chronic activation in presymptomatic amyotrophic lateral sclerosis (ALS) mice of a feedback loop involving Fas, Daxx, and FasL. Proc Natl Acad Sci U S A 2006; 103:6007-12. [PMID: 16581901 PMCID: PMC1458688 DOI: 10.1073/pnas.0508774103] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The reasons for the cellular specificity and slow progression of motoneuron diseases such as ALS are still poorly understood. We previously described a motoneuron-specific cell death pathway downstream of the Fas death receptor, in which synthesis of nitric oxide (NO) is an obligate step. Motoneurons from ALS model mice expressing mutant SOD1 showed increased susceptibility to exogenous NO as compared with controls. Here, we report a signaling mechanism whereby NO leads to death of mutant, but not control, motoneurons. Unexpectedly, exogenous NO triggers expression of Fas ligand (FasL) in cultured motoneurons. In mutant SOD1(G93A) and SOD1(G85R), but not in control motoneurons, this up-regulation results in activation of Fas, leading through Daxx to phosphorylation of p38 and further NO synthesis. This Fas/NO feedback amplification loop is required for motoneuron death in vitro. In vivo, mutant SOD1(G93A) and SOD1(G85R) mice show increased numbers of positive motoneurons and Daxx nuclear bodies weeks before disease onset. Moreover, FasL up-regulation is reduced in the presence of transgenic dominant-negative Daxx. We propose that chronic low-level activation of the Fas/NO feedback loop may underlie the motoneuron loss that characterizes familial ALS and may help to explain its slowly progressive nature.
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Affiliation(s)
- C. Raoul
- *Ecole Polytechnique Fédérale de Lausanne (EPFL), Integrative Biosciences Institute, SV IBI LEN, AAB 1 32, CH-1015 Lausanne, Switzerland
| | - E. Buhler
- Institut de Neurobiologie de la Méditerranée (INMED), Institut National de la Santé et de la Recherche Médicale (INSERM), Equipe Avenir, F-13273 Marseille Cedex 09, France
- Université de la Méditerranée, F-13288 Marseille, France; and
| | - C. Sadeghi
- *Ecole Polytechnique Fédérale de Lausanne (EPFL), Integrative Biosciences Institute, SV IBI LEN, AAB 1 32, CH-1015 Lausanne, Switzerland
| | - A. Jacquier
- Institut de Neurobiologie de la Méditerranée (INMED), Institut National de la Santé et de la Recherche Médicale (INSERM), Equipe Avenir, F-13273 Marseille Cedex 09, France
- Université de la Méditerranée, F-13288 Marseille, France; and
| | - P. Aebischer
- *Ecole Polytechnique Fédérale de Lausanne (EPFL), Integrative Biosciences Institute, SV IBI LEN, AAB 1 32, CH-1015 Lausanne, Switzerland
| | - B. Pettmann
- Université de la Méditerranée, F-13288 Marseille, France; and
- Institut de Biologie du Développement de Marseille (IBDM), Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche 623, F-13288 Marseille Cedex 09, France
| | - C. E. Henderson
- Université de la Méditerranée, F-13288 Marseille, France; and
- Institut de Biologie du Développement de Marseille (IBDM), Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche 623, F-13288 Marseille Cedex 09, France
| | - G. Haase
- Institut de Neurobiologie de la Méditerranée (INMED), Institut National de la Santé et de la Recherche Médicale (INSERM), Equipe Avenir, F-13273 Marseille Cedex 09, France
- Université de la Méditerranée, F-13288 Marseille, France; and
- To whom correspondence should be addressed at:
Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Neurobiologie de la Méditerranée (INMED), Equipe Avenir, F-13273 Marseille Cedex 09, France. E-mail:
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989
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Pun S, Santos AF, Saxena S, Xu L, Caroni P. Selective vulnerability and pruning of phasic motoneuron axons in motoneuron disease alleviated by CNTF. Nat Neurosci 2006; 9:408-19. [PMID: 16474388 DOI: 10.1038/nn1653] [Citation(s) in RCA: 501] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 01/25/2006] [Indexed: 11/09/2022]
Abstract
Neurodegenerative diseases can have long preclinical phases and insidious progression patterns, but the mechanisms of disease progression are poorly understood. Because quantitative accounts of neuronal circuitry affected by disease have been lacking, it has remained unclear whether disease progression reflects processes of stochastic loss or temporally defined selective vulnerabilities of distinct synapses or axons. Here we derive a quantitative topographic map of muscle innervation in the hindlimb. We show that in two mouse models of motoneuron disease (G93A SOD1 and G85R SOD1), axons of fast-fatiguable motoneurons are affected synchronously, long before symptoms appear. Fast-fatigue-resistant motoneuron axons are affected at symptom-onset, whereas axons of slow motoneurons are resistant. Axonal vulnerability leads to synaptic vesicle stalling and accumulation of BC12a1-a, an anti-apoptotic protein. It is alleviated by ciliary neurotrophic factor and triggers proteasome-dependent pruning of peripheral axon branches. Thus, motoneuron disease involves predictable, selective vulnerability patterns by physiological subtypes of axons, episodes of abrupt pruning in the target region and compensation by resistant axons.
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Affiliation(s)
- San Pun
- Friedrich Miescher Institut, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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990
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Dupuis L, Gonzalez de Aguilar JL, Echaniz-Laguna A, Loeffler JP. Mitochondrial dysfunction in amyotrophic lateral sclerosis also affects skeletal muscle. Muscle Nerve 2006. [DOI: 10.1002/mus.20556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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991
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Koistinen H, Prinjha R, Soden P, Harper A, Banner SJ, Pradat PF, Loeffler JP, Dingwall C. Elevated levels of amyloid precursor protein in muscle of patients with amyotrophic lateral sclerosis and a mouse model of the disease. Muscle Nerve 2006; 34:444-50. [PMID: 16856153 DOI: 10.1002/mus.20612] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease defined by motor neuron loss. Transgenic mouse models show features that closely mimic those seen in the clinical situation, reflected in the molecular changes observed in mouse models and in tissues from patients. We report a dramatic increase in the expression of amyloid precursor protein (APP) in the hindlimb muscles, but not the spinal cord of the G93A transgenic mouse model, significantly before the appearance of clinical abnormalities. APP levels were unchanged in nontransgenic mice and in mice overexpressing human wild-type Cu/Zn-dependent superoxide dismutase 1 (SOD1). Preliminary results indicate a similar change in APP expression in human deltoid muscle samples from ALS patients compared with age-matched controls. The inhibitory role of APP in innervation at the neuromuscular junction and increased expression in inclusion-body myositis suggest that presymptomatic upregulation of APP may be consistent with a potential role for APP in ALS pathology.
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Affiliation(s)
- Hannu Koistinen
- Neurodegeneration Research Department, GlaxoSmithKline Research & Development Ltd., New Frontiers Science Park, Third Avenue, Harlow, Essex, UK
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992
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Vlug AS, Teuling E, Haasdijk ED, French P, Hoogenraad CC, Jaarsma D. ATF3 expression precedes death of spinal motoneurons in amyotrophic lateral sclerosis-SOD1 transgenic mice and correlates with c-Jun phosphorylation, CHOP expression, somato-dendritic ubiquitination and Golgi fragmentation. Eur J Neurosci 2005; 22:1881-94. [PMID: 16262628 DOI: 10.1111/j.1460-9568.2005.04389.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To obtain insight into the morphological and molecular correlates of motoneuron degeneration in amyotrophic lateral sclerosis (ALS) mice that express G93A mutant superoxide dismutase (SOD)1 (G93A mice), we have mapped and characterized 'sick' motoneurons labelled by the 'stress transcription factors' ATF3 and phospho-c-Jun. Immunocytochemistry and in situ hybridization showed that a subset of motoneurons express ATF3 from a relatively early phase of disease before the onset of active caspase 3 expression and motoneuron loss. The highest number of ATF3-expressing motoneurons occurred at symptom onset. The onset of ATF3 expression correlated with the appearance of ubiquitinated neurites. Confocal double-labelling immunofluorescence showed that all ATF3-positive motoneurons were immunoreactive for phosphorylated c-Jun. Furthermore, the majority of ATF3 and phospho-c-Jun-positive motoneurons were also immunoreactive for CHOP (GADD153) and showed Golgi fragmentation. A subset of ATF3 and phosphorylated c-Jun-immunoreactive motoneurons showed an abnormal appearance characterized by a number of distinctive features, including an eccentric flattened nucleus, perikaryal accumulation of ubiquitin immunoreactivity, juxta-nuclear accumulation of the Golgi apparatus and the endoplasmic reticulum, and intense Hsp70 immunoreactivity. These abnormal cells were not immunoreactive for active caspase 3. We conclude that motoneurons in ALS-SOD1 mice prior to their death and disappearance experience a prolonged sick phase, characterized by the gradual accumulation of ubiquitinated material first in the neurites and subsequently the cell body.
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Affiliation(s)
- Angela S Vlug
- Department of Neuroscience, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, Netherlands
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993
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Hadano S, Benn SC, Kakuta S, Otomo A, Sudo K, Kunita R, Suzuki-Utsunomiya K, Mizumura H, Shefner JM, Cox GA, Iwakura Y, Brown RH, Ikeda JE. Mice deficient in the Rab5 guanine nucleotide exchange factor ALS2/alsin exhibit age-dependent neurological deficits and altered endosome trafficking. Hum Mol Genet 2005; 15:233-50. [PMID: 16321985 DOI: 10.1093/hmg/ddi440] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
ALS2/alsin is a member of guanine nucleotide exchange factors for the small GTPase Rab5 (Rab5GEFs), which act as modulators in endocytic pathway. Loss-of-function mutations in human ALS2 account for a number of juvenile recessive motor neuron diseases (MNDs). However, the normal physiological role of ALS2 in vivo and the molecular mechanisms underlying motor dysfunction are still unknown. To address these issues, we have generated mice homozygous for disruption of the Als2 gene. The Als2-null mice observed through 21 months of age demonstrated no obvious developmental, reproductive or motor abnormalities. However, immunohistochemical and electrophysiological analyses identified an age-dependent, slowly progressive loss of cerebellar Purkinje cells and disturbance of spinal motor neurons associated with astrocytosis and microglial cell activation, indicating a subclinical dysfunction of motor system in Als2-null mice. Further, quantitative epidermal growth factor (EGF)-uptake analysis identified significantly smaller-sized EGF-positive endosomes in Als2-null fibroblasts, suggesting an alteration of endosome/vesicle trafficking in the cells. Collectively, while loss of ALS2 does not produce a severe disease phenotype in mice, these Als2-null animals should provide a useful model with which to understand the interplay between endosomal dynamics and the long-term viability of large neurons such as Purkinje cells and spinal motor neurons.
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Affiliation(s)
- Shinji Hadano
- Department of Molecular Neuroscience, The Institute of Medical Sciences, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
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994
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Whitmore AV, Libby RT, John SWM. Glaucoma: thinking in new ways-a rôle for autonomous axonal self-destruction and other compartmentalised processes? Prog Retin Eye Res 2005; 24:639-62. [PMID: 15953750 DOI: 10.1016/j.preteyeres.2005.04.004] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Glaucoma is a common neurodegenerative disease that affects retinal ganglion cells (RGCs). Substantial effort is being expended to determine how RGCs die in glaucoma. As in other neurodegenerative diseases, the majority of effort focuses on characterising apoptotic self-destruct pathways. However, apoptosis is not the only self-destruct mechanism that may be activated in neurons. It is now known that neurons have distinct classes of self-destruct programme that are spatially compartmentalised. In addition to the well-described intracellular suicide machinery in the neuronal soma, responsible for apoptosis, there is another, molecularly distinct, self-destruct programme localised in the axon. Evidence also supports the existence of compartmentalised degeneration programmes in synapses and dendrites. RGCs are no exception to this. Recent data, from in vitro studies and from an inherited mouse model of glaucoma, suggest that molecularly distinct degenerative pathways underlie the destruction of RGC somata and RGC axons. In various neurodegenerative diseases, axons, dendrites and synapses often degenerate well before the cells die, and there is increasing evidence that this is important for the production of clinical symptoms and signs. We hypothesise that such compartmentalised and autonomous programmes are of critical importance in the pathophysiology of glaucoma, and we suggest that studies of these processes are essential for a complete understanding of this complex disease.
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Affiliation(s)
- Alan V Whitmore
- Divisions of Pathology & Cell Biology, Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.
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995
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Abstract
A wide range of insults can trigger axon degeneration, and axons respond with diverse morphology, topology and speed. However, recent genetic, immunochemical, morphological and pharmacological investigations point to convergent degeneration mechanisms. The principal convergence points - poor axonal transport, mitochondrial dysfunction and an increase in intra-axonal calcium - have been identified by rescuing axons with the slow Wallerian degeneration gene (Wld(S)) and studies with blockers of sodium or calcium influx. By understanding how the pathways fit together, we can combine our knowledge of mechanisms, and potentially also treatment strategies, from different axonal disorders.
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996
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Lin H, Zhai J, Schlaepfer WW. RNA-binding protein is involved in aggregation of light neurofilament protein and is implicated in the pathogenesis of motor neuron degeneration. Hum Mol Genet 2005; 14:3643-59. [PMID: 16236762 DOI: 10.1093/hmg/ddi392] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abnormal protein aggregation is emerging as a common theme in the pathogenesis of neurodegenerative disease. Our previous studies have shown that overexpression of untranslated light neurofilament (NF-L) RNA causes motor neuron degeneration in transgenic mice, leads to accumulation of ubiquitinated aggregates in degenerating cultured motor neurons and triggers aggregation of NF-L protein and co-aggregation of mutant SOD1 protein in neuronal cells. Here, we report that p190RhoGEF, an RNA-binding protein that binds to a destabilizing element in NF-L mRNA, is involved in aggregation of NF-L protein and is implicated in the pathogenesis of motor neuron degeneration. We show that p190RhoGEF co-aggregates with unassembled NF-L protein and that co-aggregation is associated with down-regulation of parent NF-L mRNA in neuronal cells. Co-expression of NF-M increases NF assembly and reduces RNA-triggered aggregation as well as loss of solubility of NF-L protein. siRNA-induced down-regulation of p190RhoGEF not only reduces aggregation and promotes assembly of NF-L and NF-M, but also causes reversal of aggregation and recovery of NF assembly in transfected cells. Examination of transgenic models of motor neuron disease shows that prominent aggregates of p190RhoGEF and NF-L and down-regulation of NF-L expression occur in degenerating motor neurons of mice expressing untranslated NF-L RNA or a G93A mutant SOD1 transgene. Moreover, aggregates of p190RhoGEF and NF-L appear as early pathological changes in presymptomatic G93A mutant SOD1 transgenic mice. Together, the findings indicate that p190RhoGEF is involved in aggregation of NF-L protein and support a working hypothesis that aggregation of p190RhoGEF and NF-L is an upstream event triggering neurotoxicity in motor neuron disease.
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Affiliation(s)
- Hong Lin
- Division of Neuropathology, University of Pennsylvania Medical School, Philadelphia, PA 19104, USA
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997
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Lladó J, Haenggeli C, Pardo A, Wong V, Benson L, Coccia C, Rothstein JD, Shefner JM, Maragakis NJ. Degeneration of respiratory motor neurons in the SOD1 G93A transgenic rat model of ALS. Neurobiol Dis 2005; 21:110-8. [PMID: 16084734 DOI: 10.1016/j.nbd.2005.06.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 06/02/2005] [Accepted: 06/15/2005] [Indexed: 11/24/2022] Open
Abstract
The transgenic mutant superoxide dismutase (SOD1) mice and rats have been important tools in attempting to understand motor neuron pathology and degeneration but the mechanism behind death in this model has not been studied. We studied the electrophysiologic and pathologic properties of the cervical motor neurons and phrenic nerves in mutant SOD1 rats and demonstrated motor neuron loss, progressive reduction of phrenic nerve compound muscle action potential amplitudes, phrenic nerve fiber loss, and diaphragm atrophy suggesting respiratory insufficiency as a significant contributing factor leading to SOD1 rat death. Unlike previous observations suggesting that a dying-back process may be occurring in the mouse model of the disease, we did not observe differences between proximal and distal axon loss in phrenic nerves of SOD1 rats. This may reflect a unique feature of respiratory motor neuron biology or may be related to the relatively rapid course of decline in the rat model when compared with the mouse SOD1 model. Significant motor neuron loss was also noted in the lumbosacral spinal cord with relative sparing of motor neurons in the cranial nuclei. Taken together, these data suggest that respiratory motor neuron loss results in significant electrophysiologic changes and diaphragmatic atrophy. These changes may play a significant role resulting in death of these animals.
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Affiliation(s)
- Jerònia Lladó
- Department of Neurology, Johns Hopkins University. 600 N. Wolfe Street, Meyer 6-119, Baltimore, MD 21287, USA
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998
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WOOLEY CHRISTINEM, SHER ROGERB, KALE AJIT, FRANKEL WAYNEN, COX GREGORYA, SEBURN KEVINL. Gait analysis detects early changes in transgenic SOD1(G93A) mice. Muscle Nerve 2005; 32:43-50. [PMID: 15880561 PMCID: PMC1350398 DOI: 10.1002/mus.20228] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The effective treatment or cure of motoneuron disease will require understanding the disease processes that precede irreversible cell loss. To study these early stages, and to evaluate potential treatments in relevant animal models, requires a sensitive functional assay. To this end, we sought to determine whether the gait pattern of SOD1 transgenic mice changed prior to overt symptoms. Using a simplified video-based approach we compared the treadmill gait of C57BL/6J and B6.SOD1 transgenic mice at 8 and 10 weeks of age. B6.SOD1 mice had significantly longer stride and stance times than controls by 8 weeks. Consistent with disease progression, hindpaw measures of B6.SOD1 mice showed larger changes than front paws. Differences between control and B6.SOD1 mice increased at 10 weeks, but only because repeat testing caused habituation in control mice to a greater extent than in B6.SOD1 mice. Together the results demonstrate that simplified gait analysis is sensitive to early processes of motor system disease in mice.
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Affiliation(s)
| | - ROGER B. SHER
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
| | - AJIT KALE
- Mouse Specifics Inc., Boston, Massachusetts, USA
| | - WAYNE N. FRANKEL
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
| | - GREGORY A. COX
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
| | - KEVIN L. SEBURN
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
- Correspondence to: K. Seburn; e-mail:
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999
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Amende I, Kale A, McCue S, Glazier S, Morgan JP, Hampton TG. Gait dynamics in mouse models of Parkinson's disease and Huntington's disease. J Neuroeng Rehabil 2005; 2:20. [PMID: 16042805 PMCID: PMC1201165 DOI: 10.1186/1743-0003-2-20] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2005] [Accepted: 07/25/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gait is impaired in patients with Parkinson's disease (PD) and Huntington's disease (HD), but gait dynamics in mouse models of PD and HD have not been described. Here we quantified temporal and spatial indices of gait dynamics in a mouse model of PD and a mouse model of HD. METHODS Gait indices were obtained in C57BL/6J mice treated with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day for 3 days) for PD, the mitochondrial toxin 3-nitropropionic acid (3NP, 75 mg/kg cumulative dose) for HD, or saline. We applied ventral plane videography to generate digital paw prints from which indices of gait and gait variability were determined. Mice walked on a transparent treadmill belt at a speed of 34 cm/s after treatments. RESULTS Stride length was significantly shorter in MPTP-treated mice (6.6 +/- 0.1 cm vs. 7.1 +/- 0.1 cm, P < 0.05) and stride frequency was significantly increased (5.4 +/- 0.1 Hz vs. 5.0 +/- 0.1 Hz, P < 0.05) after 3 administrations of MPTP, compared to saline-treated mice. The inability of some mice treated with 3NP to exhibit coordinated gait was due to hind limb failure while forelimb gait dynamics remained intact. Stride-to-stride variability was significantly increased in MPTP-treated and 3NP-treated mice compared to saline-treated mice. To determine if gait disturbances due to MPTP and 3NP, drugs affecting the basal ganglia, were comparable to gait disturbances associated with motor neuron diseases, we also studied gait dynamics in a mouse model of amyotrophic lateral sclerosis (ALS). Gait variability was not increased in the SOD1 G93A transgenic model of ALS compared to wild-type control mice. CONCLUSION The distinct characteristics of gait and gait variability in the MPTP model of Parkinson's disease and the 3NP model of Huntington's disease may reflect impairment of specific neural pathways involved.
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Affiliation(s)
- Ivo Amende
- Division of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215 USA
| | - Ajit Kale
- The CuraVita Corporation, Boston, MA 02109 USA
| | - Scott McCue
- The CuraVita Corporation, Boston, MA 02109 USA
| | | | - James P Morgan
- Division of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215 USA
| | - Thomas G Hampton
- Division of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215 USA
- The CuraVita Corporation, Boston, MA 02109 USA
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1000
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Wang J, Zhai Q, Chen Y, Lin E, Gu W, McBurney MW, He Z. A local mechanism mediates NAD-dependent protection of axon degeneration. ACTA ACUST UNITED AC 2005; 170:349-55. [PMID: 16043516 PMCID: PMC2171458 DOI: 10.1083/jcb.200504028] [Citation(s) in RCA: 288] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Axon degeneration occurs frequently in neurodegenerative diseases and peripheral neuropathies. Important insight into the mechanisms of axon degeneration arose from findings that the degeneration of transected axons is delayed in Wallerian degeneration slow (Wlds) mice with the overexpression of a fusion protein with the nicotinamide adenine dinucleotide (NAD) synthetic enzyme, nicotinamide mononucleotide adenylyltransferase (Nmnat1). Although both Wlds and Nmnat1 themselves are functional in preventing axon degeneration in neuronal cultures, the underlying mechanism for Nmnat1- and NAD-mediated axon protection remains largely unclear. We demonstrate that NAD levels decrease in degenerating axons and that preventing this axonal NAD decline efficiently protects axons from degeneration. In support of a local protective mechanism, we show that the degeneration of axonal segments that have been separated from their soma could be prevented by the exogenous application of NAD or its precursor nicotinamide. Furthermore, we provide evidence that such Nmnat1/NAD-mediated protection is primarily mediated by their effects on local bioenergetics. Together, our results suggest a novel molecular pathway for axon degeneration.
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Affiliation(s)
- Jing Wang
- Division of Neuroscience, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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