| 1. |
- Ahmadi, Mahboobah, et al.
(author)
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Human extraocular muscles in ALS
- 2010
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In: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 51:7, s. 3494-3501
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Journal article (peer-reviewed)abstract
- PURPOSE. To investigate the general morphology, fiber type content, and myosin heavy chain (MyHC) composition of extraocular muscles (EOMs) from postmortem donors with amyotrophic lateral sclerosis (ALS) and to evaluate whether EOMs are affected or truly spared in this disease. METHODS. EOM and limb muscle samples obtained at autopsy from ALS donors and EOM samples from four control donors were processed for immunohistochemistry with monoclonal antibodies against distinct MyHC isoforms and analyzed by SDS-PAGE. In addition, hematoxylin and eosin staining and nicotinamide tetrazolium reductase (NADH-TR) activity were studied. RESULTS. Wide heterogeneity was observed in the appearance of the different EOMs from each single donor and between donors, irrespective of ALS type or onset. Pathologic morphologic findings in ALS EOMs included presence of atrophic and hypertrophic fibers, either clustered in groups or scattered; increased amounts of connective tissue; and areas of fatty replacement. The population of fibers stained with anti-MyHCslow tonic was smaller than that of MyHCIpositive fibers and was mostly located in the orbital layer in most of the ALS EOM samples, whereas an identical staining pattern for both fiber populations was observed in the control specimens. MyHCembryonic was notably absent from the ALS EOMs. CONCLUSIONS. The EOMs showed signs of involvement with altered fiber type composition, contractile protein content, and cellular architecture. However, when compared to the limb muscles, the EOMs were remarkably preserved. EOMs are a useful model for the study of the pathophysiology of ALS.
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| 2. |
- Bergemalm, Daniel, et al.
(author)
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Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice
- 2010
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In: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 114:2, s. 408-418
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Journal article (peer-reviewed)abstract
- Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from four different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intra-subunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, four were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
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| 3. |
- Forsberg, Karin, et al.
(author)
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Glial nuclear aggregates of superoxide dismutase-1 are regularly present in patients with amyotrophic lateral sclerosis
- 2011
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In: Acta Neuropathologica. - : SpringerLink. - 0001-6322 .- 1432-0533. ; 121:5, s. 623-634
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Journal article (peer-reviewed)abstract
- The most common cause of amyotrophic lateral sclerosis (ALS) is mutations in superoxide dismutase-1 (SOD1). Since there is evidence for the involvement of non-neuronal cells in ALS we searched for signs of SOD1 abnormalities focusing on glia. Spinal cords from 9 ALS patients carrying SOD1 mutations, 51 patients with sporadic or familial ALS who lacked such mutations, and 46 controls were examined by immunohistochemistry. A set of anti-peptide antibodies with specificity for misfolded SOD1 species was used. Misfolded SOD1 in the form of granular aggregates was regularly detected in the nuclei of ventral horn astrocytes, microglia and oligodendrocytes in ALS patients carrying and as well as lacking SOD1 mutations. There was negligible staining in neurodegenerative and non-neurological controls. Misfolded SOD1 appeared occasionally also in nuclei of motoneurons of ALS patients. The results suggest that misfolded SOD1 present in glial and motoneuron nuclei may generally be involved in ALS pathogenesis.
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| 4. |
- Forsberg, Karin, et al.
(author)
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Novel antibodies reveal inclusions containing non-native SOD1 in sporadic ALS patients
- 2010
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In: PLOS ONE. - : Public library of science. - 1932-6203. ; 5:7, s. e11552-
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Journal article (peer-reviewed)abstract
- Mutations in CuZn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) and are found in 6% of ALS patients. Non-native and aggregation-prone forms of mutant SOD1s are thought to trigger the disease. Two sets of novel antibodies, raised in rabbits and chicken, against peptides spaced along the human SOD1 sequence, were by enzyme-linked immunosorbent assay and an immunocapture method shown to be specific for denatured SOD1. These were used to examine SOD1 in spinal cords of ALS patients lacking mutations in the enzyme. Small granular SOD1-immunoreactive inclusions were found in spinal motoneurons of all 37 sporadic and familial ALS patients studied, but only sparsely in 3 of 28 neurodegenerative and 2 of 19 non-neurological control patients. The granular inclusions were by confocal microscopy found to partly colocalize with markers for lysosomes but not with inclusions containing TAR DNA binding protein-43, ubiquitin or markers for endoplasmic reticulum, autophagosomes or mitochondria. Granular inclusions were also found in carriers of SOD1 mutations and in spinobulbar muscular atrophy (SBMA) patients and they were the major type of inclusion detected in ALS patients homozygous for the wild type-like D90A mutation. The findings suggest that SOD1 may be involved in ALS pathogenesis in patients lacking mutations in the enzyme.
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| 5. |
- Graffmo, Karin S., et al.
(author)
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Expression of wild-type human superoxide dismutase-1 in mice causes amyotrophic lateral sclerosis
- 2013
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 22:1, s. 51-60
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Journal article (peer-reviewed)abstract
- A common cause of amyotrophic lateral sclerosis (ALS) is mutations in the gene encoding superoxide dismutase-1. There is evolving circumstantial evidence that the wild-type protein can also be neurotoxic and that it may more generally be involved in the pathogenesis of ALS. To test this proposition more directly, we generated mice that express wild-type human superoxide dismutase-1 at a rate close to that of mutant superoxide dismutase-1 in the commonly studied G93A transgenic model. These mice developed an ALS-like syndrome and became terminally ill after around 370 days. The loss of spinal ventral neurons was similar to that in the G93A and other mutant superoxide dismutase-1 models, and large amounts of aggregated superoxide dismutase-1 were found in spinal cords, but also in the brain. The findings show that wild-type human superoxide dismutase-1 has the ability to cause ALS in mice, and they support the hypothesis of a more general involvement of the protein in the disease in humans.
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| 6. |
- Liu, Jing-Xia, et al.
(author)
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Different impact of ALS on laminin isoforms in human extraocular muscles versus limb muscles
- 2011
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In: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology. - 0146-0404 .- 1552-5783. ; 52:7, s. 4842-4852
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Journal article (peer-reviewed)abstract
- Purpose. To determ ine the impact of amyotrophic lateral sclerosis (ALS) on the extraocular muscles (EOMs) by examining the laminin isoform composition of the basement membranes (BMs) in EOMs and limb muscles from donors with ALS.Methods. Muscle samples collected at autopsy from ALS donors and from transgenic mice overexpressing human SOD1 mutations (D90A or G93A), and age-matched controls were analyzed with immunohistochemistry using antibodies against laminin chain α2 (Lnα2), Lnα4, Lnα5, Lnβ1, Lnβ2 and Lnγ1. Neuromuscular junctions (NMJs) were identified with α-bungarotoxin.Results. Lnα2, the hallmark chain of skeletal muscle, and Lnβ2 were absent or partially absent from the BMs in a variable number of muscle fibers in most of the ALS EOMs. Three ALS donors showed dramatic decrease in the levels of these chains around their muscle fibers and NMJs. Changes in Lnα2 were not age-related and were also present in EOMs of ALS mouse models. Lnα4 was preserved in the majority of NMJs in EOM but absent in the majority of NMJs in limb muscle of ALS. The BMs around muscle fibers, NMJs, nerves and blood vessels of the majority of EOMs of ALS donors had rather normal appearance and laminin composition, but heterogeneity was observed among EOM samples of individual ALS donors and between ALS donors.Conclusions. The present study showed distinct impact of ALS on EOMs as compared to limb muscles. The EOMs maintained a normal laminin composition in their NMJs which may be instrumental for the fact that they are not typically affected in ALS.
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| 7. |
- Liu, Jing-Xia, et al.
(author)
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Distinct changes in synaptic protein composition at neuromuscular junctions of extraocular muscles versus limb muscles of ALS donors
- 2013
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:2, s. e57473-
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Journal article (peer-reviewed)abstract
- The pathophysiology of amyotrophic lateral sclerosis (ALS) is very complex and still rather elusive but in recent years evidence of early involvement of the neuromuscular junctions (NMJs) has accumulated. We have recently reported that the human extraocular muscles (EOMs) are far less affected than limb muscles at the end-stage of ALS from the same donor. The present study aimed to compare the differences in synaptic protein composition at NMJ and in nerve fibers between EOM and limb muscles from ALS donors and controls. Neurofilament light subunit and synaptophysin decreased significantly at NMJs and in nerve fibers in limb muscles with ALS whereas they were maintained in ALS EOMs. S100B was significantly decreased at NMJs and in nerve fibers in both EOMs and limb muscles of ALS donors, but other markers confirmed the presence of terminal Schwann cells in these NMJs. p75 neurotrophin receptor was present in nerve fibers but absent at NMJs in ALS limb muscles. The EOMs were able to maintain the integrity of their NMJs to a very large extent until the end-stage of ALS, in contrast to the limb muscles. Changes in Ca2+ homeostasis, reflected by altered S100B distribution, might be involved in the breakdown of nerve-muscle contact at NMJs in ALS.
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| 8. |
- Zetterström, Per, et al.
(author)
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Composition of soluble misfolded superoxide Dismutase-1 in murine models of Amyotrophic Lateral Sclerosis
- 2013
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In: Neuromolecular medicine. - : Springer Science and Business Media LLC. - 1535-1084 .- 1559-1174. ; 15:1, s. 147-158
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Journal article (peer-reviewed)abstract
- A common cause of amyotrophic lateral sclerosis is mutations in superoxide dismutase-1, which provoke the disease by an unknown mechanism. We have previously found that soluble hydrophobic misfolded mutant human superoxide dismutase-1 species are enriched in the vulnerable spinal cords of transgenic model mice. The levels were broadly inversely correlated with life spans, suggesting involvement in the pathogenesis. Here, we used methods based on antihuman superoxide dismutase-1 peptide antibodies specific for misfolded species to explore the composition and amounts of soluble misfolded human superoxide dismutase-1 in tissue extracts. Mice expressing 5 different human superoxide dismutase-1 variants with widely variable structural characteristics were examined. The levels were generally higher in spinal cords than in other tissues. The major portion of misfolded superoxide dismutase-1 was shown to be monomers lacking the C57-C146 disulfide bond with large hydrodynamic volume, indicating a severely disordered structure. The remainder of the misfolded protein appeared to be non-covalently associated in 130- and 250-kDa complexes. The malleable monomers should be prone to aggregate and associate with other cellular components, and should be easily translocated between compartments. They may be the primary cause of toxicity in superoxide dismutase-1-induced amyotrophic lateral sclerosis.
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| 9. |
- Zetterström, Per, 1980-, et al.
(author)
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Misfolded superoxide dismutase-1 in CSF from amyotrophic lateral sclerosis patients
- 2011
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In: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 117:1, s. 91-99
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Journal article (peer-reviewed)abstract
- Several of the superoxide dismutase-1 (SOD1) mutations linked to amyotrophic lateral sclerosis (ALS) lead to synthesis of structurally defective molecules, suggesting that any cytotoxic conformational species common for all mutations should be misfolded. SOD1 can be secreted and evidence from ALS model systems suggests that extracellular SOD1 may be involved in cytotoxicity. Three ELISAs specifically reacting with different sequence segments in misfolded SOD1 species were used for analysis of CSF from 38 neurological controls and from 96 ALS patients, 57 of whom were sporadic cases and 39 familial, including 22 patients carrying SOD1 mutations. Misfolded SOD1 was found in all samples. There were, however, no significant differences between patients with and without mutations, and between all the ALS patients and the controls. The estimated concentration of misfolded SOD1 in the interstitium of the CNS is a 1000 times lower than that required for appreciable cytotoxicity in model systems. The results argue against a direct cytotoxic role of extracellular misfolded SOD1 in ALS. Misfolded SOD1 in CSF cannot be used as a biomarker of ALS in patients with and without mutations in the enzyme.
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| 10. |
- Zetterström, Per, 1980-, et al.
(author)
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Proteins that bind to misfolded mutant superoxide dismutase-1 in spinal cords from transgenic ALS model mice
- 2011
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In: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 286:23, s. 20130-20136
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Journal article (peer-reviewed)abstract
- Mutant superoxide dismutase-1 (SOD1) has an unidentified toxic property that provokes ALS. Several ALS-linked SOD1 mutations cause long C-terminal truncations, which suggests that common cytotoxic SOD1 conformational species should be misfolded and that the C-terminal end cannot be involved. The cytotoxicity may arise from interaction of cellular proteins with misfolded SOD1 species. Here we specifically immunocaptured misfolded SOD1 by the C-terminal end, from extracts of spinal cords from transgenic ALS model mice. Associated proteins were identified with proteomic techniques. Two transgenic models expressing SOD1s with contrasting molecular properties were examined: the stable G93A mutant, which is abundant in the spinal cord with only a tiny subfraction misfolded, and the scarce disordered truncation mutant G127insTGGG. For comparison, proteins in spinal cord extracts with affinity for immobilized apo G93A mutant SOD1 were determined. Two-dimensional gel patterns with a limited number of bound proteins were found, which were similar for the two SOD1 mutants. Apart from neurofilament light, the proteins identified were all chaperones and by far most abundant was Hsc70. The immobilized apo G93A SOD1, which would populate a variety of conformations, was found to bind to a considerable number of additional proteins. A substantial proportion of the misfolded SOD1 in the spinal cord extracts appeared to be chaperone-associated. Still, only about 1% of the Hsc70 appeared to be associated with misfolded SOD1. The results argue against the notion that chaperone depletion is involved in ALS pathogenesis in the transgenic models and in humans carrying SOD1 mutations.
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