Wang, J., G. Xu, et al. (2002). "Fibrillar inclusions and motor neuron degeneration in transgenic mice expressing superoxide dismutase 1 with a disrupted copper-binding site." Neurobiol Dis 10(2): 128-38. Mutations in Cu/Zn superoxide dismutase 1 (SOD1) have been linked to dominantly inherited forms of amyotrophic lateral sclerosis (FALS). To test the hypothesis that the toxicity of mutant SOD1 originates in Cu(2+)-mediated formation of toxic radicals, we generated transgenic mice that express human SOD1 that encodes disease-linked mutations at two of the four histidine residues that are crucial for the coordinated binding of copper (H46R/H48Q). We demonstrate that mice expressing this mutant, which possesses little or no superoxide scavenging activity, develop motor neuron disease. Hence, mutations in SOD1 that disrupt the copper-binding site do not eliminate toxicity. We note that the pathology of the H46R/H48Q mice is dominated by fibrillar (Thioflavin-S-positive) inclusions and that similar inclusions were evident in mouse models that express the G37R, G85R, and G93A variants of human SOD1. Overall, our data are consistent with the hypothesis that the aberrant folding/aggregation of mutant SOD1 is a prominent feature in the pathogenesis of motor neuron disease. Hand, C. K. and G. A. Rouleau (2002). "Familial amyotrophic lateral sclerosis." Muscle Nerve 25(2): 135-59. The increasing complexity of the pathways implicated in the pathogenesis of familial amyotrophic lateral sclerosis (ALS) has stimulated intensive research in many directions. Genetic analysis of familial ALS has yielded six loci and one disease gene (SOD1), initially suggesting a role for free radicals in the disease process, although the mechanisms through which the mutant exerts toxicity and results in selective motor neuron death remain uncertain. Numerous studies have focused on structural elements of the affected cell, emphasizing the role of neurofilaments and peripherin and their functional disruption in disease. Other topics examined include cellular homeostasis of copper and calcium, particularly in the context of oxidative stress and the processes of protein aggregation, glutamate excitotoxicity, and apoptosis. It has become evident that there is considerable interplay between these mechanisms and, as the role of each is established, a common picture may emerge, enabling the development of more targeted therapies. This study discusses the main areas of investigation and reviews the findings. Fujita, Y., K. Okamoto, et al. (2002). "The Golgi apparatus is fragmented in spinal cord motor neurons of amyotrophic lateral sclerosis with basophilic inclusions." Acta Neuropathol (Berl) 103(3): 243-7. The mechanisms of neuronal death in amyotrophic lateral sclerosis (ALS) are not known. A pathological aggregation of cytoplasmic constituents in the form of variety of inclusions may play a role in the pathogenesis of neuronal death. Cytoplasmic basophilic inclusions (BIs) in motor neurons are commonly found in sporadic juvenile ALS. The functional significance of these inclusions is not known, i.e., whether they represent a protective reaction for the isolation of abnormal products from the cytoplasm, or a sign of irreversible neuronal damage. To gain insights on the significance of BIs we asked whether neurons with BIs had an intact or fragmented Golgi apparatus (GA), a sign of neuronal degeneration reported not only in sporadic and familial ALS with mutations of the Cu/Zn superoxide dismutase gene (SOD1), but also in transgenic mice expressing the G93A mutation of SOD1. In these mice fragmentation of the GA of spinal cord motor neurons was found months before the onset of paralysis. We report here that all neurons bearing the inclusions showed fragmentation and reduced number of GA. These results suggest that common pathogenetic mechanisms are involved in the production of BIs and in the fragmentation of the GA. Watanabe, M., M. Dykes-Hoberg, et al. (2001). "Histological evidence of protein aggregation in mutant SOD1 transgenic mice and in amyotrophic lateral sclerosis neural tissues." Neurobiol Dis 8(6): 933-41. The mechanisms leading to neurodegeneration in ALS (amyotrophic lateral sclerosis) are not well understood, but cytosolic protein aggregates appear to be common in sporadic and familial ALS as well as transgenic mouse models expressing mutant Cu/Zn superoxide dismutase (SOD1). In this study, we systematically evaluated the presence of these aggregates in three different mouse models (G93A, G85R, and G37R SOD1) and compared these aggregates to those seen in cases of sporadic and familial ALS. Inclusions and loss of motor neurons were observed in spinal cords of all of these three mutant transgenic lines. Since a copper-mediated toxicity hypothesis has been proposed to explain the cytotoxic gain-of-function of mutant SOD1, we sought to determine the involvement of the copper chaperone for SOD1 (CCS) in the formation of protein aggregates. Although all aggregates contained CCS, SOD1 was not uniformly found in the inclusions. Similarly, CCS-positive skein-like inclusions were rarely seen in ALS neurons. These studies do not provide strong evidence for a causal role of CCS in aggregate formation, but they do suggest that protein aggregation is a common event in all animal models of the disease. Selected proteins, such as the glutamate transporter GLT-1, were not typically observed within the inclusions. Most inclusions were positively stained with antibodies recognizing ubiquitin, proteasome, Hsc70 in transgenic lines, and some Hsc70-positive inclusions were detected in sporadic ALS cases. Overall, these observations suggest that inclusions might be sequestered into ubiquitin-proteasome pathway and some chaperone proteins such as Hsc70 may be involved in formation and/or degradation of these inclusions. Shibata, N. (2001). "Transgenic mouse model for familial amyotrophic lateral sclerosis with superoxide dismutase-1 mutation." Neuropathology 21(1): 82-92. Familial amyotrophic lateral sclerosis (ALS) with mutations in the gene for superoxide dismutase-1 (SOD1) is clinicopathologically reproduced by transgenic mice expressing mutant forms of SOD1 detectable in familial ALS patients. Motor neuron degeneration associated with SOD1 mutation has been thought to result from a novel neurotoxicity of mutant SOD1, but not from a reduction in activity of this enzyme, based on autosomal dominant transmission of SOD1 mutant familial ALS and its transgenic mouse model, clinical severity of the ALS patients independent to enzyme activity, no ALS-like disease in SOD1 knockout or wild-type SOD1-overexpressing mice, and clinicopathological severity of mutant SOD1 transgenic mice dependent on transgene copy numbers. Proposed mechanisms of motor neuron degeneration such as oxidative injury, peroxynitrite toxicity, cytoskeletal disorganization, glutamate excitotoxicity, disrupted calcium homeostasis, SOD1 aggregation, carbonyl stress and apoptosis have been discussed. Intracytoplasmic vacuoles, indicative of increased oxidative damage to the mitochondria and endoplasmic reticulum, in the neuropil and motor neurons appear in high expressors of mutant SOD1 transgenic mice but not in low expressors of the mice or familial ALS patients, suggesting that overexpression of mutant SOD1 in mice may enhance oxidative stress generation from this enzyme. Thus, transgenic mice carrying small transgene copy numbers of mutant SOD1 would provide a beneficial animal model for SOD1 mutant familial ALS. Such a model would contribute to elucidating the pathomechanism of this disease and establishing new therapeutic agents. Kato, S., K. Nakashima, et al. (2001). "Formation of advanced glycation end-product-modified superoxide dismutase-1 (SOD1) is one of the mechanisms responsible for inclusions common to familial amyotrophic lateral sclerosis patients with SOD1 gene mutation, and transgenic mice expressing human SOD1 gene mutation." Neuropathology 21(1): 67-81. Neuronal Lewy body-like hyaline inclusions (LBHI) and astrocytic hyaline inclusions (Ast-HI) are morphological hallmarks of certain familial amyotrophic lateral sclerosis (FALS) patients with superoxide dismutase-1 (SOD1) gene mutations, and transgenic mice expressing the human SOD1 gene mutation. The ultrastructure of inclusions in both diseases is identical: the essential common constituents are granule-coated fibrils approximately 15-25nm in diameter and granular materials. Detailed immunohistochemical analyses have shown that the essential common protein of the inclusions in both diseases is an SOD1 protein. This finding, together with the immunoelectron microscopy finding that the abnormal granule-coated fibrils comprising the inclusions are positive for SOD1, indicates that these granule-coated fibrils containing SOD1 are important evidence for mutant SOD1-linked disease in human and mouse. For immunoelectron microscopy, the granule-coated fibrils are modified by advanced glycation endproducts (AGE) such as N(epsilon)-carboxymethyl lysine, pyrraline and pentosidine (Maillard reaction). Based on the fact that AGE themselves are insoluble molecules with direct cytotoxic effects, the granule-coated fibrils and granular materials are not digested by the lysosomal and ubiquitin systems. The neurons and astrocytes of the normal individuals and non-transgenic mice show no significant immunoreactivity for AGE. Considered with the mutant-SOD1 aggregation toxicity, a portion of the SOD1 comprising both types of the inclusion is modified by the AGE, and the formation of the AGE-modified SOD1 (probably AGE-modified mutant SOD1) is one of the mechanisms responsible for the aggregation (i.e. granule-coated fibril formation). Kato, S., H. Sumi-Akamaru, et al. (2001). "Copper chaperone for superoxide dismutase co-aggregates with superoxide dismutase 1 (SOD1) in neuronal Lewy body-like hyaline inclusions: an immunohistochemical study on familial amyotrophic lateral sclerosis with SOD1 gene mutation." Acta Neuropathol (Berl) 102(3): 233-8. The copper chaperone for superoxide dismutase (CCS) interacts with Cu/Zn-binding superoxide dismutase 1 (SOD1) specifically and delivers copper to SOD1. To determine the role of the CCS-SOD1 interaction in the pathogenesis of SOD1-mutated familial amyotrophic lateral sclerosis (FALS) patients, we produced an affinity-purified rabbit antibody against CCS and investigated the immunohistochemical localization of both CCS and SOD1 in neuronal Lewy body-like hyaline inclusions (LBHIs) in the spinal cords of two FALS patients with a two-base pair deletion at codon 126 in the SOD1 gene and three FALS patients with an Ala to Val substitution at codon 4. The LBHIs in anterior horn cells from the five FALS patients showed identical immunoreactivities for CCS: the reaction product deposits with the antibody against CCS were generally restricted to the periphery of the core and halo-type LBHIs. The localizations of the immunoreactivities for CCS and SOD1 were similar in the inclusions: both CCS and SOD1 colocalized in neuronal LBHIs in the five mutant SOD1-linked FALS patients. Our results suggest that the specific interaction and aggregation of CCS-SOD1 (probably CCS-mutant SOD1) in SOD1-mutated FALS patients may amplify the formation of inclusions and emphasize a more marked mutant SOD1-mediated toxicity. Cluskey, S. and D. B. Ramsden (2001). "Mechanisms of neurodegeneration in amyotrophic lateral sclerosis." Mol Pathol 54(6): 386-92. Amyotrophic lateral sclerosis (ALS) is the most common variant of motor neurone disease affecting adults that usually strikes during mid to late life. Its aetiology is still poorly understood, although a major breakthrough came with the discovery that mutations in the Cu/Zn superoxide dismutase (SOD1) gene affect approximately 20% of patients with familial ALS. Experiments using both transgenic mice and ALS tissues have been useful in delineating other genetic defects in ALS. However, because only a subset of cases can be attributed to one particular molecular defect (such as mutation of SOD1 or the gene encoding neurofilament H), the aetiology of ALS is likely to be multifactorial. This review discusses the major mechanisms of neurodegeneration in ALS, such as oxidative stress, glutaminergic excitotoxicity, damage to vital organelles, and aberrant protein aggregation. Wang, H. S., A. Taniguchi, et al. (2000). "Immunohistochemistry of advanced glycation end products in neurofilamentous axonal spheroids induced by beta-beta'-iminodipropionitrile in lower motor neurons of rat." J Neurol Sci 177(2): 139-45. Chronic parenteral administration of beta-beta'-iminodipropionitrile (IDPN) in adult female rats induces large neurofilament-rich axonal spheroids (AXS) in spinal motor neurons closely resembling those AXS in early phases of amyotrophic lateral sclerosis. Immunohistochemistry of advanced glycosylation end-products (AGEs) in axonal spheroids was performed in the present study. Anti-AGE and anti-neurofilament antibodies strongly co-labeled IDPN-induced axonal spheroids, whereas motor neuron soma showed little AGE immunoreactivity. In an attempt to modify and intensify glycosylation, another group of IDPN rats was made hyperglycemic with streptozotocin after IDPN intoxication. These hyperglycemic rats showed AXS with striking AGE immunoreactivity. An additional group of rats made hyperglycemic before IDPN intoxication showed markedly diminished AXS formation, with a few small AGE-positive AXS in anterior horns. Findings suggest that AGEs are involved in neurofilament crosslinking as well as disassembly of neurofilament induced by IDPN with or without hyperglycemia. Hyperglycemia did not intensify neurofilament aggregation. Additional immunohistochemistry revealed not only aberrant phosphorylation, but also intense local production of Cu/Zn superoxide dismutase and nitrotyrosine in axonal spheroids, probably secondary to superoxide generation as a consequence of AGE production at neurofilament protein, impeding its assembly as hypothesized in motoneuron diseases. Stieber, A., J. O. Gonatas, et al. (2000). "Aggregation of ubiquitin and a mutant ALS-linked SOD1 protein correlate with disease progression and fragmentation of the Golgi apparatus." J Neurol Sci 173(1): 53-62. Transgenic mice that express the G93A mutation of human Cu,Zn superoxide dismutase (SOD1(G93A)), found in familial amyotrophic lateral sclerosis (FALS), showed clinical symptoms and histopathological changes of sporadic ALS, including fragmentation of the neuronal Golgi apparatus (GA). The finding of fragmented neuronal GA in asymptomatic mice, months before the onset of paralysis, suggests that the GA is an early target of the pathological processes causing neuronal degeneration. Transgenic mice expressing human SOD1(G93A) have aggregates of mutant protein and ubiquitin in neuronal and glial cytoplasm; they appeared first in the neuropil and later in the perikarya of motor neurons, where they were adjacent to fragmented GA. The aggregates of SOD1(G93A) appeared in neuronal perikarya of asymptomatic mice containing fragmented GA. The numbers of neurons with deposits of SOD1(G93A) and fragmented GA progressively increased with age. Immuno-electron microscopy using colloidal gold showed labeling of ubiquitin and SOD1 over 13 nm thick cytoplasmic filaments. Spinal cord extracts showed a 20-fold increase of SOD1(G93A) in transgenic mice compared to the wild-type protein in controls. The results suggest a causal relationship between the aggregation of mutant SOD1 and ubiquitin, fragmentation of the Golgi apparatus of motor neurons and neurodegeneration. Shibata, N., A. Hirano, et al. (2000). "Superoxide dismutase-1 mutation-related neurotoxicity in familial amyotrophic lateral sclerosis." Amyotroph Lateral Scler Other Motor Neuron Disord 1(3): 143-61. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by motor neuron system involvement, and is epidemiologically subclassified into sporadic, familial and endemic forms. About 20% of ALS families are associated with mutations in the gene for superoxide dismutase-1 (SOD1) encoded on chromosome 21q22.1. Several studies have pointed to a variety of functions of mutant SOD1, which has enhanced catalytic activity of the peroxynitrite-mediated tyrosine nitration, readily releases the reactive Cu ions, induces apoptotic cell death, has enhanced peroxidase activity, damages the mitochondria to release Ca2+, and forms SOD1-containing aggregates in the cytoplasm. Many of these studies have obtained evidence for increased oxidative damage in ALS. On the other hand, some reports disagree with oxidative damage involvement in SOD1 mutant ALS. In considering the findings of increased oxidative damage in mutant SOD1-expressing transgenic mice, it should be remembered that overexpression of mutant SOD1 may enhance oxidative stress generation from this enzyme. In this review, we present the clinicopathological features of SOD1 mutant familial ALS and its transgenic mouse model, and also discuss SOD1 mutation-related neurotoxicity, including SOD1 protein aggregation and post-translational protein modification. Okado-Matsumoto, A., T. Myint, et al. (2000). "Gain in functions of mutant Cu,Zn-superoxide dismutases as a causative factor in familial amyotrophic lateral sclerosis: less reactive oxidant formation but high spontaneous aggregation and precipitation." Free Radic Res 33(1): 65-73. Eight mutant Cu,Zn-superoxide dismutases (SODs) related to familial amyotrophic lateral sclerosis (FALS) were produced in a baculovirus/insect cell expression system and their molecular properties in terms of hydroxyl radical formation and aggregation were compared with the wild-type enzyme. Treatment of the enzymes with Chelex 100 resin decreased Cu contents as well as SOD activities in all mutant Cu,Zn-SODs, indicating that the affinities of the enzymes for copper ion were decreased. Contrary to previous reports, all the mutant Cu,Zn-SODs exhibited less reactive oxidant producing ability in the presence of hydrogen peroxide than the wild-type enzyme. Both SOD activities and their reactive oxidant forming correlated well with the copper ion content of the molecules. In addition, the proteins spontaneously aggregated and were precipitated by simple centrifugation at 12,000g for 20 min in keeping their enzyme activities. Since hyaline inclusions found in FALS patients with SOD1 mutations contained components which were reactive to anti-Cu,Zn-SOD antibody, a primary reaction caused by mutant SOD1 may be attributed to their propensity to form aggregates. Aggregated but still active mutant SOD1 would be expected to mediate the formation of reactive oxygen species and nitrosylation in a more condensed state. Kato, S., S. Horiuchi, et al. (2000). "Advanced glycation endproduct-modified superoxide dismutase-1 (SOD1)-positive inclusions are common to familial amyotrophic lateral sclerosis patients with SOD1 gene mutations and transgenic mice expressing human SOD1 with a G85R mutation." Acta Neuropathol (Berl) 100(5): 490-505. To clarify the biological significance of the neuronal Lewy body-like hyaline inclusions and astrocytic hyaline inclusions characteristically found in patients with familial amyotrophic lateral sclerosis with superoxide dismutase-1 (SOD1) gene mutations and in transgenic mice expressing human SOD1 with G85R mutation, the detailed protein composition in both types of inclusions was immunohistochemically analyzed using 45 different antibodies. Both types of inclusions had very strong immunoreactivity for SOD1. The SOD1-positive inclusions in both cell types were also immunoreactive for the insoluble advanced glycation endproducts (AGEs) such as Nepsilon-(carboxymethyl)lysine (CML), pyrraline and pentosidine: both inclusions in both conditions were ultrastructurally composed of the granule-coated fibrils that had immunoreactivities to CML and pyrraline. Both types of inclusions were negative for stress-response proteins (SRPs), 4-hydroxy-2-nonenal (HNE), acrolein, nitric oxide synthases (NOSs) and nitrotyrosine as representative markers of oxidative stress. The neurons and astrocytes of the normal individuals and non-transgenic mice showed no significant immunoreactivity for SOD1, AGEs, SRPs, HNE, acrolein, NOSs or nitrotyrosine. Our results suggest that a portion of the SOD1 composing both type of inclusions, probably toxic mutant SOD1, is modified by the AGEs, and that the formation of the AGE-modified SOD1 is one of the mechanisms responsible for the aggregation involving no significant oxidative mechanisms. Kato, S., M. Takikawa, et al. (2000). "New consensus research on neuropathological aspects of familial amyotrophic lateral sclerosis with superoxide dismutase 1 (SOD1) gene mutations: inclusions containing SOD1 in neurons and astrocytes." Amyotroph Lateral Scler Other Motor Neuron Disord 1(3): 163-84. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that primarily involves the motor neuron system. Approximately 5-10% of ALS is familial. Superoxide dismutase 1 (SOD1) gene mutations are shown to be associated with about 20% of familial ALS (FALS) patients. The neuronal Lewy-body-like hyaline inclusion (LBHI) and astrocytic hyaline inclusion (Ast-HI) are morphological hallmarks of certain SOD1-linked FALS patients with SOD1 gene mutant and transgenic mice expressing human SOD1 with G85R mutation. From the detailed immunohistochemical analyses, the essential common protein of both inclusions is SOD1. Ultrastructurally, both inclusions consist of granule-coated fibrils 15-25 nm in diameter. Based on the immuno-electron microscopical finding that these abnormal granule-coated fibrils are positive for SOD1, the formation (or aggregation) of the abnormal fibrils containing SOD1 would be essential evidence in diseases caused by various SOD1 mutations. The granule-coated fibrils are also modified by advanced glycation end products (AGEs). The AGEs themselves are insoluble molecules with direct toxic effects on cells. AGE formation of SOD1 composing the granule-coated fibrils (probable AGE-modified mutant SOD1) may amplify their aggregation and produce a more marked toxicity. Johnston, J. A., M. J. Dalton, et al. (2000). "Formation of high molecular weight complexes of mutant Cu, Zn-superoxide dismutase in a mouse model for familial amyotrophic lateral sclerosis." Proc Natl Acad Sci U S A 97(23): 12571-6. Deposition of aggregated protein into neurofilament-rich cytoplasmic inclusion bodies is a common cytopathological feature of neurodegenerative disease. How-or indeed whether-protein aggregation and inclusion body formation cause neurotoxicity are presently unknown. Here, we show that the capacity of superoxide dismutase (SOD) to aggregate into biochemically distinct, high molecular weight, insoluble protein complexes (IPCs) is a gain of function associated with mutations linked to autosomal dominant familial amyotrophic lateral sclerosis. SOD IPCs are detectable in spinal cord extracts from transgenic mice expressing mutant SOD several months before inclusion bodies and motor neuron pathology are apparent. Sequestration of mutant SOD into cytoplasmic inclusion bodies resembling aggresomes requires retrograde transport on microtubules. These data indicate that aggregation and inclusion body formation are mechanistically and temporally distinct processes. Cleveland, D. W. and J. Liu (2000). "Oxidation versus aggregation - how do SOD1 mutants cause ALS?" Nat Med 6(12): 1320-1. Anneser, J. (2000). "Molecular basis of treatment in motor neurone disease." Neurol Sci 21(5 Suppl): S913-8. The pathways leading to motorneuron degeneration in amyotrophic lateral sclerosis (ALS) are complex. Excitotoxicity, oxidative damage and, maybe, abnormal aggregation of neurofilaments are key events on which therapeutical strategies can be designed. This paper reviews current knowledge on these strategies. Even though we should be aware that appropriate management of disease symptoms remains the most effective therapeutical intervention, understanding the pathophysiology of ALS is essential for developing new therapies. Al-Chalabi, A. and P. N. Leigh (2000). "Recent advances in amyotrophic lateral sclerosis." Curr Opin Neurol 13(4): 397-405. The mechanisms by which mutations of the SOD1 gene cause selective motor neuron death remain uncertain, although interest continues to focus on the role of peroxynitrite, altered peroxidase activity of mutant SOD1, changes in intracellular copper homeostasis, protein aggregation, and changes in the function of glutamate transporters leading to excitotoxicity. Neurofilaments and peripherin appear to play some part in motor neuron degeneration, and amyotrophic lateral sclerosis is occasionally associated with mutations of the neurofilament heavy chain gene. Linkage to several chromosomal loci has been established for other forms of familial amyotrophic lateral sclerosis, but no new genes have been identified. In the clinical field, interest has been shown in the population incidence and prevalence of amyotrophic lateral sclerosis and the clinical variants that cause diagnostic confusion. Transcranial magnetic stimulation has been used to detect upper motor neuron damage and to explore cortical excitability in amyotrophic lateral sclerosis, and magnetic resonance imaging including proton magnetic resonance spectroscopy and diffusion weighted imaging also provide useful information on the upper motor neuron lesion. Aspects of care including assisted ventilation, nutrition, and patient autonomy are addressed, and underlying these themes is the requirement to measure quality of life with a new disease-specific instrument. Progress has been made in developing practice parameters. Riluzole remains the only drug to slow disease progression, although interventions such as non-invasive ventilation and gastrostomy also extend survival. Cookson, M. R. and P. J. Shaw (1999). "Oxidative stress and motor neurone disease." Brain Pathol 9(1): 165-86. The effects of oxidative stress within post mitotic cells such as neurones may be cumulative, and injury by free radical species is a major potential cause of the age-related deterioration in neuronal function seen in several neurodegenerative diseases. There is strong evidence that oxidative stress plays an important role in the pathogenesis of motor neurone disease (MND). Point mutations in the antioxidant enzyme Cu,Zn superoxide dismutase (SOD1) are found in some pedigrees with the familial form of MND. How mutations in this ubiquitous enzyme cause the relatively selective cell death of specific groups of motor neurones is not clear, although a number of hypotheses have been forwarded. These include (1) the formation of hydroxyl radicals, (2) the catalysis of reactions of the nitrogen centred oxidant species peroxynitrite, (3) toxicity of copper or zinc and (4) protein aggregation. Some experimental support for these different hypotheses has been produced by manipulating cells in culture to express the mutant SOD1 proteins and by generating transgenic mice which over-express mutant SOD1. Observations in these model systems are, in some cases at least, supported by observations made on pathological material from patients with similar SOD1 mutations. Furthermore, there are reports of evidence of free radical mediated damage to neurones in the sporadic form of MND. Several lines of evidence suggest that alterations in the glutamatergic neurotransmitter system may also play a key role in the injury to motor neurones in sporadic MND. There are several important subcellular targets, which may be preferentially impaired within motor neurones, including neurofilament proteins and mitochondria. Future research will need to identify the aspects of the molecular and physiological phenotype of human motor neurones that makes them susceptible to degeneration in MND, and to identify those genetic and environmental factors which combine to cause this disease in individuals and in familial pedigrees. Chou, S. M., C. Y. Han, et al. (1999). "A receptor for advanced glycosylation endproducts (AGEs) is colocalized with neurofilament-bound AGEs and SOD1 in motoneurons of ALS: immunohistochemical study." J Neurol Sci 169(1-2): 87-92. Neurofilament (NF)-bound AGEs colocalize immunochemically with SOD1 in the motoneurons of patients with ALS. Among three types of AGE receptors reported in the human brain, AGE-R1 (oligosaccharyltransferase family) and AGE-R2 (substrate of protein kinase C) have been found in neurons, while AGE-R3 is restricted to glia. The present study investigates which of these receptors may be responsible for binding AGEs in the NF conglomerates of motoneurons. Immunostaining of paraffin sections from eight ALS patients (five sporadic and three familial) and three control cases was performed with antibodies directed against R1 and R2, in parallel with those against AGEs and SOD1. The sites of AGE-R1 immunoreactivity (IR) in motoneurons were in conformity to those of NF-associated AGE and SOD1 IRs. By contrast, the IR of R2 was negative in NF conglomerates. Negative R2 IR for NF conglomerates was outlined by surrounding coarse R2 immunopositive granules in the perikaryon. No IR for R1 or R2 was found in hyaline or Bunina inclusions. There was no extraneuronal expression of IR for AGE-R1 or AGEs in microglia or astroglia around the NF accumulation. The colocalization of AGE, AGE-R1, and SOD1 at NF conglomerates in motoneurons supports the notion that AGE-mediated oxidative stress and protein aggregation may be implicated in NF conglomeration and ALS pathogenesis. Bruijn, L. I., M. K. Houseweart, et al. (1998). "Aggregation and motor neuron toxicity of an ALS-linked SOD1 mutant independent from wild-type SOD1." Science 281(5384): 1851-4. Analysis of transgenic mice expressing familial amyotrophic lateral sclerosis (ALS)-linked mutations in the enzyme superoxide dismutase (SOD1) have shown that motor neuron death arises from a mutant-mediated toxic property or properties. In testing the disease mechanism, both elimination and elevation of wild-type SOD1 were found to have no effect on mutant-mediated disease, which demonstrates that the use of SOD mimetics is unlikely to be an effective therapy and raises the question of whether toxicity arises from superoxide-mediated oxidative stress. Aggregates containing SOD1 were common to disease caused by different mutants, implying that coaggregation of an unidentified essential component or components or aberrant catalysis by misfolded mutants underlies a portion of mutant-mediated toxicity.