Development of a rat model of amyotrophic lateral sclerosis expressing a human SOD1 transgene

Mutations in copper–zinc superoxide dismutase gene (SOD1) have been linked to some familial cases of ALS. We report here that rats that express a human SOD1 transgene with two different ALS‐associated mutations (G93A and H46R) develop striking motor neuron degeneration and paralysis. By comparing the two transgenic rats with different SOD1 mutations, we demonstrate that the time course in these rats was similar to human SOD1‐mediated familial ALS. As in the human disease and transgenic ALS mice, pathological analysis shows selective loss of motor neurons in the spinal cords of these transgenic rats. In addition, typical neuronal Lewy body‐like hyaline inclusions as well as astrocytic hyaline inclusions identical to those in human familial ALS are observed in the spinal cords. The larger size of this rat model as compared with the ALS mice will facilitate studies involving manipulations of spinal fluid (implantation of intrathecal catheters for chronic therapeutic studies; CSF sampling) and spinal cord (e.g., direct administration of viral‐ and cell‐mediated therapies).     

Activated p38MAPK is a novel component of the intracellular inclusions found in human amyotrophic lateral sclerosis and mutant SOD1 transgenic mice

Cytoskeletal abnormalities with accumulation of ubiquilated inclusions in the anterior horn cells are a pathological hallmark of both familial and sporadic amyotrophic lateral sclerosis (ALS) and of mouse models for ALS. Phosphorylated neurofilaments besides ubiquitin and dorfin have been identified as one of the major components of the abnormal intracellular perikaryal aggregates. As we recently found that p38 mitogen-activated protein kinase (p38MAPK) colocalized with phosphorylated neurofilaments in spinal motor neurons of SOD1 mutant mice, a model of familial ALS, we investigated whether this kinase also contributed to the inclusions found in ALS patients and SOD1 mutant mice. Intense immunoreactivity for activated p38MAPK was observed in degenerating motor neurons and reactive astrocytes in ALS cases. The intracellular immunostaining for activated p38MAPK appeared in some neurons as filamentous skein-like and ball-like inclusions, with an immunohistochemical pattern identical to that of ubiquitin. Intracellular p38MAPK-positive aggregates containing ubiquitin and neurofilaments were also found in the spinal motor neurons of SOD1 mutant mice. Our observations indicate that activation of p38MAPK might contribute significantly to the pathology of motor neurons in ALS.     

Familial amyotrophic lateral sclerosis and Cu/Zn superoxide dismutase mutation

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder that involves mainly the motor neuron system. Five to 10 percent of the ALS cases are familial; most others are sporadic. Several mutations in the superoxide dismutase-1 (SOD1) gene have recently been shown to be associated with about 20% of familial ALS patients. The reduced enzyme activity of many mutant SOD1 points to the possibility that a loss-of-function effect of the mutant enzyme is responsible for the pathogenesis of the disease. However, this conflicts with the autosomal dominant inheritance of SOD1 mutation-associated ALS and the normal SOD1 activity in homozygous patients in a SOD1-linked ALS family. Current biochemical investigations have provided evidence that mutant SOD1 may catalyze the peroxynitrite-mediated nitration of protein tyrosine residues, release copper and zinc ions, facilitate apoptosis of neurons and have enhanced peroxidase activity. Immunocytochemical studies demonstrated the presence of intense SOD1 immunoreactivity in Lewy body-like inclusions, which are characteristic features of a certain form of familial ALS with posterior column involvement, in the lower motor neurons of patients in ALS families with different SOD1 mutations. More recently, strains of transgenic mice expressing mutant SOD1 have been established. These mice clinicopathologically develop a motor neuron disease mimicking human ALS with the exception of pronounced intraneuronal vacuolar degeneration. The overexpression of wild-type SOD1 in mice has failed to give rise to the disease. Only one transgene for mutant SOD1 is enough to cause motor neuron degeneration and the severity of clinical course correlates with the transgene copy number. These observations in SOD1-linked familial ALS and its transgenic mouse model suggest a novel neurotoxic function of mutant SOD1.     

Familial amyotrophic lateral sclerosis with a novel Leu126Ser mutation in the copper/zinc superoxide dismutase gene showing mild clinical features and lewy body-like hyaline inclusions

BACKGROUND: Mutations in the SOD1 gene are responsible for approximately 25% of all familial amyotrophic lateral sclerosis (ALS) cases. However, the correlation between the clinical and pathological features and the various SOD1 gene mutations has not been well characterized. OBJECTIVES: To screen the SOD1 gene in search of potential mutations and to obtain clinical and pathological data for 2 Japanese families with ALS. DESIGN: Clinical histories and neurological findings, gross and microscopic pathological features, and DNA analysis of the SOD1 gene. RESULTS: The 2 families with ALS showed a novel missense mutation in the SOD1 gene, which was heterozygous for point mutation TTG to TCG, causing substitution of leucine for serine at codon 126 (Leu126Ser) in exon 5. Clinically, patients showed slower disease progression and lack of upper motor neuron signs. Neuropathologically, the autopsied patient showed the form of familial ALS with posterior column involvement, and the pontocerebellar tract and the dentate nuclei of the cerebellum were also involved. Furthermore, abundant Lewy body-like hyaline inclusions were observed in the affected motor and nonmotor neurons. CONCLUSIONS: Familial ALS with a novel Leu126Ser mutation in the SOD1 gene showed mild clinical features and lack of upper motor neuron signs. We believe that Leu126Ser might be associated with the clinical features and that the mutation site in the SOD1 gene and disease duration might be associated with the formation of Lewy body-like hyaline inclusions.     

Amyotrophic lateral sclerosis is a non-amyloid disease in which extensive misfolding of SOD1 is unique to the familial form

Amyotrophic lateral sclerosis (ALS) is a conformational disease in which misfolding and aggregation of proteins such as SOD1 (familial ALS) and TDP-43 (sporadic ALS) are central features. The conformations adopted by such proteins within motor neurons in affected patients are not well known. We have developed a novel conformation-specific antibody (USOD) targeted against SOD1 residues 42–48 that specifically recognizes SOD1 in which the beta barrel is unfolded. Use of this antibody, in conjunction with the previously described SEDI antibody that recognizes the SOD1 dimer interface, allows a detailed investigation of the in vivo conformation of SOD1 at the residue-specific level. USOD and SEDI immunohistochemistry of spinal cord sections from ALS cases resulting from SOD1 mutations (A4V and ΔG27/P28) shows that inclusions within remaining motor neurons contain SOD1 with both an unfolded beta barrel and a disrupted dimer interface. Misfolded SOD1 can also be immunoprecipitated from spinal cord extracts of these cases using USOD. However, in ten cases of sporadic ALS, misfolded SOD1 is not detected by either immunohistochemistry or immunoprecipitation. Using the amyloid-specific dyes, Congo Red and Thioflavin S, we find that SOD1-positive inclusions in familial ALS, as well as TDP-43- and ubiquitin-positive inclusions in sporadic ALS, contain non-amyloid protein deposits. We conclude that SOD1 misfolding is not a feature of sporadic ALS, and that both SOD1-ALS and sporadic ALS, rather than being amyloid diseases, are conformational diseases that involve amorphous aggregation of misfolded protein. This knowledge will provide new insights into subcellular events that cause misfolding, aggregation and toxicity.     

Involvement of the brain stem reticular formation in familial amyotrophic lateral sclerosis.

The reticular formation of the brain stem of three cases of familial amyotrophic lateral sclerosis (ALS) with posterior column and spinocerebellar tract involvement showed a paucity of large neurons, chromatolytic neurons and Lewy body-like intracytoplasmic inclusions. Some of the remaining neurons were stained focally by antibodies to phosphorylated neurofilaments and ubiquitin; the staining patterns were similar to those seen in anterior horn cells. Within the reticular formation, the medial part of the medulla oblongata was most pronouncedly affected. The reticular formation should be among the systems other than motor neurons that may be involved in this type of familial ALS.     

Nonoxidative protein glycation is implicated in familial amyotrophic lateral sclerosis with superoxide dismutase-1 mutation

To assess a role for oxidative stress in the pathogenesis of amyotrophic lateral sclerosis (ALS), we analyzed the immunohistochemical localization of 8-hydroxy-2′-deoxyguanosine (OHdG) as a nucleic acid oxidation product, acrolein-protein adduct and 4-hydroxy-2-nonenal (HNE)-protein adduct as lipid peroxidation products, N ^ɛ-carboxymethyl-lysine (CML) as a lipid peroxidation or protein glycoxidation product, pentosidine as a protein glycoxidation product, and imidazolone and pyrraline as nonoxidative protein glycation products in the spinal cord of three familial ALS patients with superoxide dismutase-1 (SOD1) A4V mutation, six sporadic ALS patients, and six age-matched control individuals. The spinal cord sections of the control cases did not show any distinct immunoreactivities for these examined products. In the familial ALS cases, intense immunoreactivities for pyrraline and CML were confined to the characteristic Lewy body-like hyaline inclusions, and imidazolone immunoreactivity was located in the cytoplasm of the residual motor neurons. No significant immunoreactivities for other examined products were detected in the familial ALS spinal cords. In the sporadic ALS cases, intense immunoreactivities for pentosidine, CML and HNE-protein adduct were seen in the cytoplasm of the degenerated motor neurons, and OHdG immunoreactivity was located in the cell nuclei of the residual neurons and glial cells. The present results indicate that oxidative reactions are involved in the disease processes of sporadic ALS, while there is no evidence for increased oxidative damage except for CML deposition in the familial ALS spinal cords. Furthermore, it is likely that the accumulation of pyrraline and imidazolone supports a nonoxidative mechanism in SOD1-related motor neuron degeneration. Received: 18 August 1999 / Revised, accepted: 17 November 1999     

Pathological TDP-43 distinguishes sporadic amyotrophic lateral sclerosis from amyotrophic lateral sclerosis with SOD1 mutations

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a common, fatal motor neuron disorder with no effective treatment. Approximately 10% of cases are familial ALS (FALS), and the most common genetic abnormality is superoxide dismutase-1 (SOD1) mutations. Most ALS research in the past decade has focused on the neurotoxicity of mutant SOD1, and this knowledge has directed therapeutic strategies. We recently identified TDP-43 as the major pathological protein in sporadic ALS. In this study, we investigated TDP-43 in a larger series of ALS cases (n = 111), including familial cases with and without SOD1 mutations. METHODS: Ubiquitin and TDP-43 immunohistochemistry was performed on postmortem tissue from sporadic ALS (n = 59), ALS with SOD1 mutations (n = 15), SOD-1-negative FALS (n = 11), and ALS with dementia (n = 26). Biochemical analysis was performed on representative cases from each group. RESULTS: All cases of sporadic ALS, ALS with dementia, and SOD1-negative FALS had neuronal and glial inclusions that were immunoreactive for both ubiquitin and TDP-43. Cases with SOD1 mutations had ubiquitin-positive neuronal inclusions; however, no cases were immunoreactive for TDP-43. Biochemical analysis of postmortem tissue from sporadic ALS and SOD1-negative FALS demonstrated pathological forms of TDP-43 that were absent in cases with SOD1 mutations. INTERPRETATION: These findings implicate pathological TDP-43 in the pathogenesis of sporadic ALS. In contrast, the absence of pathological TDP-43 in cases with SOD1 mutations implies that motor neuron degeneration in these cases may result from a different mechanism, and that cases with SOD1 mutations may not be the familial counterpart of sporadic ALS.     

HtrA2/Omi‐immunoreactive intraneuronal inclusions in the anterior horn of patients with sporadic and Cu/Zn superoxide dismutase (SOD1) mutant amyotrophic lateral sclerosis

Y. Kawamoto, H. Ito, Y. Kobayashi, Y. Suzuki, I. Akiguchi, H. Fujimura, S. Sakoda, H. Kusaka, A. Hirano and R. Takahashi (2010) Neuropathology and Applied Neurobiology 36, 331–344
HtrA2/Omi‐immunoreactive intraneuronal inclusions in the anterior horn of patients with sporadic and Cu/Zn superoxide dismutase (SOD1) mutant amyotrophic lateral sclerosis Aims: HtrA2/Omi is a mitochondrial serine protease that promotes the apoptotic processes, but the relationship between HtrA2/Omi and amyotrophic lateral sclerosis (ALS) is still unknown. The purpose of the present study was to determine whether abnormal expression of HtrA2/Omi occurs in patients with ALS. Methods: We prepared autopsied spinal cord tissues from 7 control subjects, 11 patients with sporadic ALS (SALS) and 4 patients with Cu/Zn superoxide dismutase (SOD1)‐related familial ALS (FALS). We then performed immunohistochemical studies on HtrA2/Omi using formalin‐fixed, paraffin‐embedded sections from all of the cases. Results: In the control subjects, the anterior horn cells were mildly to moderately immunostained with HtrA2/Omi. In the patients with SALS, strong HtrA2/Omi immunoreactivity was found in some skein‐like inclusions and round hyaline inclusions as well as many spheroids, but Bunina bodies were immunonegative for HtrA2/Omi. In the patients with SOD1‐related FALS, Lewy body‐like hyaline inclusions were observed in three cases and conglomerate inclusions were observed in the remaining case, and both types of inclusions were intensely immunopositive for HtrA2/Omi. Conclusions: These results suggest that abnormal accumulations of HtrA2/Omi may occur in several types of motor neuronal inclusions in the anterior horn from SALS and SOD1‐linked FALS cases, and that HtrA2/Omi may be associated with the pathogenesis of both types of ALS.     

The neuronal Golgi apparatus is fragmented in transgenic mice expressing a mutant human SOD1, but not in mice expressing the human NF-H gene

Fragmentation of the Golgi apparatus (GA) of motor neurons was first described in sporadic amyotrophic lateral sclerosis (ALS) and later confirmed in transgenic mice expressing the G93A mutation of the gene encoding the enzyme Cu,Zn superoxide dismutase (SOD1(G93A)) found in some cases of familial ALS. In these transgenic mice, however, the fragmentation of the neuronal GA was associated with cytoplasmic and mitochondrial vacuoles not seen in ALS. The present new series of transgenic mice expressing 14-17 trans gene copies of SOD1(G93A), compared to 25 copies in the mice we studied previously, showed consistent fragmentation of the GA of spinal cord motor neurons, axonal swellings, Lewy-like body inclusions in neurons and glia, but none of the cytoplasmic or mitochondrial vacuoles originally reported. Thus, this animal model recapitulates the clinical and most neuropathological findings of sporadic ALS. Neurofilaments (NF) accumulate in axons and, less often, in neuronal perikarya in most cases of sporadic ALS and they have been implicated in its pathogenesis. In order to investigate whether fragmentation of the neuronal GA also occurs in association with accumulation of perikaryal NFs, we studied the organelle in transgenic mice expressing the heavy subunit of human neurofilaments (NF-H) which developed a motor neuronopathy resembling ALS. The neuronal GA of mice expressing NF-H, however, was intact despite massive accumulation of NFs in both perikarya and axons of motor neurons. In contrast, in transgenic mice expressing SOD1(G93A), the GA was fragmented despite the absence of accumulation of perikaryal NFs. These findings suggest that, in transgenic mice with neuronopathies caused by the expression of mutant SOD1(G93A) or the human NF-H, the GA and the perikaryal NFs are independently involved in the pathogenesis. The evidence suggests that the GA plays a central role in the pathogenesis of the vast majority of sporadic ALS and in FALS with SOD1 mutations.     

Involvement of spinal motor neurons in parkin‐positive autosomal recessive juvenile parkinsonism

We intensively examined the spinal cord of an autosomal recessive juvenile parkinsonism (ARJP) female patient with a homozygous exon 3 deletion in the parkin gene, anticipating a possible involvement of anterior horn neurons. Although the clinical features of the patient were consistent with parkinsonism as a result of parkin mutation, her tendon reflex was abolished in the lower limbs. This feature was in contrast with hyperreflexia, usually found in previous reports of ARJP. Histologically, on the level of the cervical, thoracic, and sacral spinal cord, anterior horn neurons were well preserved and normal. However, the lumbar spinal cord exhibited many swellings of proximal axons (spheroids) and degenerative changes in the somata of the large anterior horn neurons such as central chromatolysis, cystatin C‐negative small eosinophilic inclusions, and eosinophilic Lewy body‐like inclusions. Ultrastructurally, accumulations of neurofilaments and abnormal structures, such as inclusion bodies similar to skein‐like inclusions and disorganized rough endoplasmic reticulum, were observed in the somata and neuronal processes. Lewy body‐like inclusions in this study were positively immunostained for both α‐synuclein and ubiquitin that closely resemble Lewy bodies, but are different from Lewy body‐like inclusions negatively immunostained for α‐synuclein in amyotrophic lateral sclerosis. These findings suggest that eosinophilic inclusions that closely resemble Lewy bodies may be formed in the spinal motor neurons of ARJP patients with parkin mutations and the motor neurons of these patients may be vulnerable to neurodegeneration.     

Colocalization of Bunina bodies and TDP‐43 inclusions in a case of sporadic amyotrophic lateral sclerosis with Lewy body‐like hyaline inclusions

Sporadic amyotrophic lateral sclerosis (sALS) is characterized pathologically by loss of upper and lower motor neurons with occurrence of transactivation response DNA‐binding protein 43 kDa (TDP‐43)‐immunoreactive skein‐like and round hyaline inclusions. Lewy body‐like hyaline inclusions (LBHIs) are also found in a small proportion of sALS cases as well as in individuals with familial ALS with mutations in the Cu/Zu superoxide dismutase (SOD1) gene. LBHIs in sALS are immunopositive for TDP‐43, but not for SOD1. The occurrence of Bunina bodies (BBs) is another key pathological feature of sALS. BBs are immunonegative for TDP‐43 but immunopositive for cystatin C, transferrin, peripherin and sortilin‐related receptor CNS expressed 2 (SorCS2). Despite differences between BBs and TDP‐43 inclusions in terms of protein constituents and ultrastructure, the two inclusions are known to be linked. We recently encountered a case of sALS of 10 months duration in which many round hyaline inclusions, LBHIs and BBs were found in the anterior horn cells of the spinal cord. Our immunohistochemical and ultrastructural examinations revealed the presence of BBs within the skein‐like and round hyaline inclusions, and in the LBHIs. Colocalization of BB‐related proteins (cystatin C, transferrin and SorCS2) and TDP‐43 was also confirmed in the halo of LBHIs as well as in the marginal portion of the skein‐like and round hyaline inclusions. These findings suggest that there is some relationship between BBs and TDP‐43‐immunoreactive inclusions in terms of their formation processes.     

TDP-43 immunoreactivity in neuronal inclusions in familial amyotrophic lateral sclerosis with or without SOD1 gene mutation

Recently, 43-kDa TAR DNA-binding protein (TDP-43) was identified as a component of ubiquitinated inclusions (UIs) in sporadic amyotrophic lateral sclerosis (SALS). To clarify whether TDP-43 immunoreactivity is present in neuronal inclusions in familial ALS (FALS), we examined immunohistochemically the brains and spinal cords from four cases of FALS, two with Cu/Zn superoxide dismutase (SOD1) gene mutation and two without, together with three cases of SALS and three control subjects, using two antibodies, one polyclonal and one monoclonal, against TDP-43. Neuropathologically, the SOD1-related FALS cases were characterized by Lewy body-like hyaline inclusions (LBHIs) in the lower motor neurons. On the other hand, the SOD1-unrelated FALS cases showed degeneration restricted to the upper and lower motor neuron systems, with Bunina bodies (BBs) and UIs in the lower motor neurons, being indistinguishable from SALS. No cytoplasmic TDP-43 immunoreactivity was observed in the control subjects or SOD1-related FALS cases; LBHIs were ubiquitinated, but negative for TDP-43. UIs observed in the SALS and SOD1-unrelated FALS cases were clearly positive for TDP-43. BBs were negative for this protein. Interestingly, in these SALS and FALS cases, glial cells were also found to have cytoplasmic TDP-43-positive inclusions. These findings indicate that the histological and molecular pathology of SALS can occur as a phenotype of FALS without SOD1 mutation.     

An autopsy case of sporadic amyotrophic lateral sclerosis associated with the I113T SOD1 mutation

A 64‐year‐old man noticed weakness in his arms and dyspnea upon exertion. Four months later he was admitted to our hospital, where muscle atrophy and hyperactive deep tendon reflexes in the arms were observed upon examination. A needle electromyograph study revealed acute and chronic denervation in the extremities, and he was diagnosed as having amyotrophic lateral sclerosis (ALS). Seven months after onset of the disease, he died of respiratory failure. Neuropathologically, neuronal cell loss was observed in the motor cortex, hypoglossal nuclei, cervical and lumbar anterior horns and Clarke's nuclei. Some of the remaining neurons contained neurofilamentous conglomerate inclusions (CIs). A small number of Lewy body‐like hyaline inclusions (LBHIs) were also observed. No the Bunina bodies, skein‐like inclusions or basophilic inclusions were detectable. Tract degeneration was moderate in the dorsal and ventral spinocerebellar tracts, mild in the pyramidal tract, but not discerned in the posterior column. Immunohistochemical examinations revealed that the CIs were strongly positive for phosphorylated neurofilament and moderately positive for ubiquitin and Cu/Zn superoxide dismutase 1 (SOD1). Moreover, a number of phosphorylated tau protein‐positive globose neurofibrillary tangles (NFTs) and threads were observed in the periaqueductal gray matter, oculomotor nuclei and trochlear nuclei. Although the family history was negative for neuromuscular diseases, the neuropathological findings indicated features of familial ALS with a SOD1 mutation. In fact, DNA analysis of frozen‐brain tissue revealed the presence of the I113T SOD1 mutation. This case represents the first one of this mutation in a patient who showed CIs as well as LBHIs in the motor neurons at the same time, in addition to the NFTs in the mesencephalic tegmentum.     

An autopsied case of sporadic adult‐onset amyotrophic lateral sclerosis with FUS‐positive basophilic inclusions

Basophilic inclusions (BIs), which are characterized by their staining properties of being weakly argyrophilic, reactive with Nissl staining, and immunohistochemically negative for tau and transactive response (TAR) DNA‐binding protein 43 (TDP‐43), have been identified in patients with juvenile‐onset amyotrophic lateral sclerosis (ALS) and adult‐onset atypical ALS with ophthalmoplegia, autonomic dysfunction, cerebellar ataxia, or a frontal lobe syndrome. Mutations in the fused in sarcoma gene (FUS) have been reported in cases of familial and sporadic ALS, and FUS immunoreactivity has been demonstrated in basophilic inclusion body disease (BIBD), neuronal intermediate filament inclusion disease (NIFID), and atypical frontotemporal lobar degeneration with ubiquitin‐positive and tau‐negative inclusions (aFTLD‐U). In the present study, we immunohistochemically and ultrastructurally studied an autopsy case of sporadic adult‐onset ALS with numerous BIs. The patient presented with the classical clinical course of ALS since 75 years of age and died at age 79. Postmortem examination revealed that both Betz cells in the motor cortex and motor neurons in the spinal cord were affected. The substantia nigra was spared. Notably, BIs were frequently observed in the motor neurons of the anterior horns, the inferior olivary nuclei, and the basal nuclei of Meynert. BIs were immunopositive for p62, LC3, and FUS, but immunonegative for tau, TDP‐43, and neurofilament. Ultrastructurally, BIs consisted of filamentous or granular structures associated with degenerated organelles with no limiting membrane. There were no Bunina bodies, skein‐like inclusions, or Lewy‐like inclusions. All exons and exon/intron boundaries of the FUS gene were sequenced but no mutations were identified.     

Histological Evidence of Protein Aggregation in Mutant SOD1 Transgenic Mice and in Amyotrophic Lateral Sclerosis Neural Tissues

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.     

Advanced glycation endproducts are deposited in neuronal hyaline inclusions: a study on familial amyotrophic lateral sclerosis with superoxide dismutase-1 mutation

To determine the role of advanced glycation endproducts (AGE) in the pathogenesis of familial amyotrophic lateral sclerosis (ALS) with superoxide dismutase-1 (SOD1) mutation, we investigated the immunohistochemical localization of N(epsilon)-carboxymethyl-lysine (CML), one of the major AGE structures, in spinal cords from three familial ALS patients with a heterozygous Ala to Val substitution at codon 4 in the gene for SOD1. Neuronal hyaline inclusions (NHIs), the abnormal structures seen in some of the remaining lower motor neurons of familial ALS patients with SOD1 mutation, were intensely stained by a monoclonal antibody specific for CML in contrast to the only weakly stained cytoplasm. Immunoelectron microscopy depicted the CML determinants restricted to the granule-associated thick linear structures that mainly compose the NHIs. The NHIs were also recognized by antibodies to SOD1, phosphorylated neurofilament protein and ubiquitin. No focal collection of either CML or SOD1 was found in neurons of the control individuals. Our results indicate that CML is a component of the NHIs of familial ALS patients with SOD1 mutation, and suggest that the CML formation may be mediated by protein glycoxidation or lipid peroxidation in the presence of oxidative stress from mutant SOD1, in association with motor neuron degeneration.     

Inflammatory mechanisms in amyotrophic lateral sclerosis

Neuroinflammation is a pathological hallmark in human amyotrophic lateral sclerosis (ALS) patients and in the transgenic models of the disease. The importance of glial cell activation and pro-inflammatory cytokines in ALS has been confirmed by numerous studies. For instance, tumor necrosis factor-α (TNF-α), a major pro-inflammatory cytokine, activates microglia and cause neurotoxicity in motor neurons. More recently, the relationship of nuclear factor-κB (NF-κB) and motor neuron degeneration has garnered attention since optineurin (OPTN) mutations were reported in familial ALS. OPTN negatively regulates TNF-α-induced NF-κB activation, but OPTN mutations can lead to dysinhibition of NF-κB-induced neurotoxicity. Notably, OPTN-positive inclusions are observed not only in familial ALS with OPTN mutation but also in sporadic ALS and in familial ALS with SOD1 and fused in sarcoma mutations, suggesting that OPTN- and NF-κB-related pathways are relevant to the general pathomechanisms of ALS. In this review, we discuss inflammatory aspects of ALS comprising the roles of cytokines, glial cells, and T cells.     

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

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– 25 nm 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 im‐munoelectron microscopy, the granule‐coated fibrils are modified by advanced glycation endproducts (AGE) such as N^?‐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).     

Familial amyotrophic lateral sclerosis (FALS) with a novel SOD1 gene mutation: a clinicopathological study]

We describe a patient with familial amyotrophic lateral sclerosis (FALS) in whom we identified a substitution of G for CGTTTA at codon 144 in the Cu/Zn superoxide dismutase 1 (SOD1) gene, causing amino acid changes from leucine to phenylalanine, valine and a stop codon (L144FVX). This mutation is novel, and so we report the clinical and neuropathological features of this case compared with those of other FALS cases with SOD1 mutations. A 39-year-old woman developed muscle weakness and atrophy in the hands, which rapidly progressed and expanded to other muscles, resulting in respiratory insufficiency and death at only 10 months after the onset Her grandmother, father and uncle had also been diagnosed as having ALS. The most noticeable neuropathological findings in the present case were marked loss of large motor neurons in the anterior horns associated with the frequent appearance of cord-like swollen, partially SOD 1- and ubiquitin-immunopositive axons. These findings together with the absence of Bunina bodies are compatible with the neuropathology of FALS with SOD1 gene mutation, although Lewy body-like inclusions characteristic for this condition were not observed.