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Ogawa M, Uchida K, Yamato O, Inaba M, Uddin MM, Nakayama H. Neuronal Loss and Decreased GLT-1 Expression Observed in the Spinal Cord of Pembroke Welsh Corgi Dogs With Canine Degenerative Myelopathy. Vet Pathol 2013; 51:591-602. [DOI: 10.1177/0300985813495899] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease that is frequently found in Pembroke Welsh Corgi (PWC) dogs. Canine DM is potentially a spontaneous animal model for human amyotrophic lateral sclerosis (ALS) because of similar lesions and the involvement of superoxide dismutase 1 (SOD1) mutation. However, the ventral horn lesion in DM has not been characterized in detail. Glutamate excitotoxicity due to deficiency of the glutamine-glutamate cycle has been implicated in neuron death in ALS. Thus, we examined 5 PWC dogs with an SOD1 mutation that were affected by DM, 5 non-DM PWC dogs, and 5 Beagle dogs without neurologic signs to assess the neuronal changes and the expression levels of 2 glial excitatory amino acid transporters (glutamate transporter 1 [GLT-1] and glutamate/aspartate transporter [GLAST]). The number of neurons in the spinal ventral horns of the DM dogs was significantly decreased, whereas no change was found in the cell size. Chromatolysis, lipofuscin-laden neurons, and marked synapse loss were also observed. GLT-1 expression was strikingly decreased in DM dogs, whereas GLAST expression showed no significant change. The results indicate that excitotoxicity related to the reduced expression of GLT-1, but not GLAST, may be involved in neuron loss in DM, as in human ALS, whereas intraneuronal events may differ between the 2 diseases.
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Affiliation(s)
- M. Ogawa
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - K. Uchida
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - O. Yamato
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - M. Inaba
- Laboratory of Molecular Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan
| | - M. M. Uddin
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - H. Nakayama
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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Crisp MJ, Beckett J, Coates JR, Miller TM. Canine degenerative myelopathy: biochemical characterization of superoxide dismutase 1 in the first naturally occurring non-human amyotrophic lateral sclerosis model. Exp Neurol 2013; 248:1-9. [PMID: 23707216 DOI: 10.1016/j.expneurol.2013.05.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/08/2013] [Accepted: 05/14/2013] [Indexed: 11/19/2022]
Abstract
Mutations in canine superoxide dismutase 1 (SOD1) have recently been shown to cause canine degenerative myelopathy, a disabling neurodegenerative disorder affecting specific breeds of dogs characterized by progressive motor neuron loss and paralysis until death, or more common, euthanasia. This discovery makes canine degenerative myelopathy the first and only naturally occurring non-human model of amyotrophic lateral sclerosis (ALS), closely paralleling the clinical, pathological, and genetic presentation of its human counterpart, SOD1-mediated familial ALS. To further understand the biochemical role that canine SOD1 plays in this disease and how it may be similar to human SOD1, we characterized the only two SOD1 mutations described in affected dogs to date, E40K and T18S. We show that a detergent-insoluble species of mutant SOD1 is present in spinal cords of affected dogs that increases with disease progression. Our in vitro results indicate that both canine SOD1 mutants form enzymatically active dimers, arguing against a loss of function in affected homozygous animals. Further studies show that these mutants, like most human SOD1 mutants, have an increased propensity to form aggregates in cell culture, with 10-20% of cells possessing visible aggregates. Creation of the E40K mutation in human SOD1 recapitulates the normal enzymatic activity but not the aggregation propensity seen with the canine mutant. Our findings lend strong biochemical support to the toxic role of SOD1 in canine degenerative myelopathy and establish close parallels for the role mutant SOD1 plays in both canine and human disorders.
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Affiliation(s)
- Matthew J Crisp
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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CHANG HS, KAMISHINA H, MIZUKAMI K, MOMOI Y, KATAYAMA M, RAHMAN MM, UDDIN MM, YABUKI A, KOHYAMA M, YAMATO O. Genotyping Assays for the Canine Degenerative Myelopathy-Associated c.118G>A (p.E40K) Mutation of the SOD1 Gene Using Conventional and Real-Time PCR Methods: A High Prevalence in the Pembroke Welsh Corgi Breed in Japan. J Vet Med Sci 2013; 75:795-8. [DOI: 10.1292/jvms.12-0451] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Hye-Sook CHANG
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Hiroaki KAMISHINA
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan
| | - Keijiro MIZUKAMI
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Yasuyuki MOMOI
- Laboratory of Diagnostic Imaging, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Masaaki KATAYAMA
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Faculty of Agriculture, Iwate, 3–18–8 Ueda, Morioka, Iwate 020–8550, Japan
| | - Mohammad Mahbubur RAHMAN
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Mohammad Mejbah UDDIN
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Akira YABUKI
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Moeko KOHYAMA
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
| | - Osamu YAMATO
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Kohrimoto, Kagoshima 890–0065, Japan
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