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We evaluated a battery of functional tests for investigating the effects of edaravone, a free radical scavenger, in SOD1 transgenic (H46R) rat model of amyotrophic lateral sclerosis. Edaravone (1.5 or 3.0mg/kg/h) or saline was administered intravenously to rats by continuous infusion (1h per day) for 2days, followed by a 2-day holiday. Lifetime and duration of illness were evaluated, and motor function was assessed using the hind-foot reflex test, landing foot-splay test, rota rod test and inclined plate test at a predetermined time point at which half of the control animals had died. Statistical comparison of motor functions of edaravone-treated and control SOD1 transgenic rats at an objectively determined time point was confirmed to be feasible. Edaravone-treated male rats showed significantly better performance in the landing foot-splay test. The present model seems suitable for evaluating motor function of H46R SOD1 transgenic rats, and be useful for examining the therapeutic potential of edaravone to treat amyotrophic lateral sclerosis., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: ALS2/alsin is a guanine nucleotide exchange factor for the small GTPase Rab5 and involved in macropinocytosis-associated endosome fusion and trafficking, and neurite outgrowth. ALS2 deficiency accounts for a number of juvenile recessive motor neuron diseases (MNDs). Recently, it has been shown that ALS2 plays a role in neuroprotection against MND-associated pathological insults, such as toxicity induced by mutant Cu/Zn superoxide dismutase (SOD1). However, molecular mechanisms underlying the relationship between ALS2-associated cellular function and its neuroprotective role remain unclear., Methodology/principal Findings: To address this issue, we investigated the molecular and pathological basis for the phenotypic modification of mutant SOD1-expressing mice by ALS2 loss. Genetic ablation of Als2 in SOD1(H46R), but not SOD1(G93A), transgenic mice aggravated the mutant SOD1-associated disease symptoms such as body weight loss and motor dysfunction, leading to the earlier death. Light and electron microscopic examinations revealed the presence of degenerating and/or swollen spinal axons accumulating granular aggregates and autophagosome-like vesicles in early- and even pre-symptomatic SOD1(H46R) mice. Further, enhanced accumulation of insoluble high molecular weight SOD1, poly-ubiquitinated proteins, and macroautophagy-associated proteins such as polyubiquitin-binding protein p62/SQSTM1 and a lipidated form of light chain 3 (LC3-II), emerged in ALS2-deficient SOD1(H46R) mice. Intriguingly, ALS2 was colocalized with LC3 and p62, and partly with SOD1 on autophagosome/endosome hybrid compartments, and loss of ALS2 significantly lowered the lysosome-dependent clearance of LC3 and p62 in cultured cells., Conclusions/significance: Based on these observations, although molecular basis for the distinctive susceptibilities to ALS2 loss in different mutant SOD1-expressing ALS models is still elusive, disturbance of the endolysosomal system by ALS2 loss may exacerbate the SOD1(H46R)-mediated neurotoxicity by accelerating the accumulation of immature vesicles and misfolded proteins in the spinal cord. We propose that ALS2 is implicated in endolysosomal trafficking through the fusion between endosomes and autophagosomes, thereby regulating endolysosomal protein degradation in vivo.

We examined morphological alterations in the mitochondria in the spinal cord of H46R mutant Cu/Zn superoxide dismutase transgenic mice; these mice serve as a model for human familial amyotrophic lateral sclerosis. The disease in the mice is characterized by initial muscle weakness and atrophy in the legs, very long clinical courses, and widespread pathological changes of the spinal cord that extend beyond the motor system and includes many neuropil aggregates that lack vacuoles. At the preclinical stage, we found alterations in the mitochondrial cristae that included focal electron-dense changes, whorled membranous and electron-dense amorphous structures, and outward projections of outer and inner membranes predominantly in proximal axons. At the overt disease stage, these mitochondrial alterations were more frequent and were also found in somata, dendrites, presynaptic terminals, and astrocyte cytoplasm. By immunoelectron microscopy, no accumulations of Cu/Zn superoxide dismutase- or ubiquitin-positive immunogold particles were observed in either normal-appearing or abnormal mitochondria. These findings suggest that predominant mitochondrial alterations in the proximal axons begin in the preclinical stage and may be involved in the pathogenetic mechanisms of motor neuron degeneration in these transgenic mice via disruption of the axonal transport of substrates necessary for neuronal viability; this disruption may lead to motor neuron death.

Mutations in Cu/Zn superoxide dismutase (SOD1) have been linked to some familial cases of amyotrophic lateral sclerosis (ALS). In familial ALS kinders with mutations in the SOD1 gene, the age of onset of weakness varies greatly but the duration of illness appears to be characteristic to each mutation. For example, in patients with the L84V mutation, the average life expectancy is less than 1.5 year after the onset of symptoms, whereas patients harboring the H46R mutation have an average life expectancy of 18 years after the disease onset. In view of the evidence supporting the idea that familial ALS variants of SOD1 enzymes acquire toxic properties, the variations in the duration of illness in the different kinders might arise because each mutation imparts different degrees of toxicity to the mutant protein. We developed rats that express a human SOD1 transgene with two different ALS-associated mutations (G93A and H46R) develop striking motor neuron degeneration and paralysis. 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). Hepatocyte growth factor (HGF) is one of the most potent survival-promoting factors for motor neurons. To examine its both protective effect on motor neurons and therapeutic potential, we administered human recombinant HGF (hrHGF) by continuous intrathecal delivery to G93A transgenic (Tg) rats at onset of paralysis for 4 weeks. Intrathecal administration of hrHGF attenuates motor neuron degeneration and prolonged the duration of the disease by 63%. Our results indicated the therapeutic efficacy of continuous intrathecal administration of hrHGF in Tg rats. The results should prompt further clinical trials in ALS using continuous intrathecal administration of hrHGF.

Neuronal Lewy body-like hyaline inclusions (LBHI) and astrocytic hyaline inclusions (Ast-HI) containing mutant Cu/Zn superoxide dismutase 1 (SOD1) are morphological hallmarks of familial amyotrophic lateral sclerosis (FALS) associated with mutant SOD1. However, the mechanisms by which mutant SOD1 contributes to formation of LBHI/Ast-HI in FALS remain poorly defined. Here, we report induction of LBHI/Ast-HI-like hyaline inclusions (LHIs) in vitro by ER stress in neuroblastoma cells. These LHI closely resemble LBHI/Ast-HI in patients with SOD1-linked FALS. LHI and LBHI/Ast-HI share the following features: 1) eosinophilic staining with a pale core, 2) SOD1, ubiquitin and ER resident protein (KDEL) positivity and 3) the presence of approximately 15-25 nm granule-coated fibrils, which are morphological hallmark of mutant SOD1-linked FALS. Moreover, in spinal cord neurons of L84V SOD1 transgenic mice at presymptomatic stage, we observed aberrant aggregation of ER and numerous free ribosomes associated with abnormal inclusion-like structures, presumably early stage neuronal LBHI. We conclude that the LBHI/Ast-HI seen in human patients with mutant SOD1-linked FALS may arise from ER dysfunction.

Human familial amyotrophic lateral sclerosis with an H46R mutant Cu/Zn superoxide dismutase (SOD1) gene is characterized by initial muscle weakness and atrophy in the legs and a very long-term clinical course (approximately 15 years). Transgenic mice with this mutation generated in our laboratory occasionally showed aggregates in the anterior horns and axonal degeneration in all white matter sections of the spinal cord on plastic sections at the presymptomatic stages (12 and 16 weeks old), although conventional staining revealed no pathologic changes. At the symptomatic stages (20 and 24 weeks), loss of anterior horn neurons was observed. On plastic sections, aggregates were frequently seen not only in the anterior horns but also in the posterior horns and in all sections of white matter. Degenerated fibers were observed in the anterior and posterior roots as well as in white matter. Electron and immunoelectron microscopic observation revealed human SOD1- and ubiquitin-positive aggregates consisting of intermediate filaments in the anterior horn even from an early presymptomatic stage. Thus, H46R mutant SOD1 transgenic mice are characterized by widespread pathologic changes of the spinal cord that extend beyond the motor system, including many aggregates lacking vacuoles. The close pathologic similarity makes this animal model suitable for the investigation of human familial amyotrophic lateral sclerosis with the mutation.

Histological rescue of superoxide dismutase1 (SOD1)-mutated hepatocytes from mutant SOD1 stress is investigated from the viewpoint of upregulation of the redox system [peroxiredoxin (Prx) and glutathione peroxidase (GPx)]. Histopathological and immunohistochemical studies using antibodies against PrxI/PrxII/GPxI were carried out on specimens from four different strains of animal models of mutant SOD1-linked familial amyotrophic lateral sclerosis (ALS). In the livers of the ALS animal models in the presymptomatic stage without motor neuron loss, both swollen and eosinophilic hepatocytes with vacuolation pathology were observed. After developing motor deficits, this swelling and vacuolation ceased to be apparent. In the terminal stage when severe motor neuron loss was observed, these hepatocytes recovered and appeared normal. In redox system-related immunohistochemical preparations, almost all of the normal hepatocytes expressed the redox system-related enzymes PrxI/PrxII/GPxI. In the presymptomatic stage, some hepatocytes did not express redox system-related enzymes. After clinical onset, over 75% of hepatocytes showed overexpression of PrxI/PrxII/GPxI, i. e., upregulation of the redox system. At the end stage, near normal PrxI/PrxII/GPxI expression was observed again in the hepatocytes. Redox system upregulation in SOD1-mutated hepatocytes rescues hepatocytes from the mutant SOD1 stress that leads to motor neuron death.

Accumulation of misfolded Cu/Zn superoxide dismutase (SOD1) occurs in patients with a subgroup of familial amyotrophic lateral sclerosis (fALS). To identify the conversion of SOD1 from a normally soluble form to insoluble aggregates, we investigated the change of SOD1 solubility with aging in fALS-linked H46R SOD1 transgenic mice. Mutant SOD1 specifically altered to insoluble forms, which were sequentially separated into Triton X-100-insoluble/sodium dodecyl sulfate (SDS)-soluble and SDS-insoluble/formic acid-soluble species. In spinal cords, the levels of SDS-dissociable soluble SOD1 monomers and SDS-stable soluble dimers were significantly elevated before motor dysfunction onset. In COS-7 cells expressing H46R SOD1, treatment with proteasome inhibitors recapitulated the alteration of SOD1 solubility in transgenic mice. In contrast, overexpression of Hsp70 reduced accumulation of mutant-specific insoluble SOD1. SDS-soluble low molecular weight species of H46R SOD1 may appear as early misfolded intermediates when their concentration exceeds the capacity of the proteasome and molecular chaperones.

The recent development of a rat model of amyotrophic lateral sclerosis (ALS) in which the rats harbor a mutated human SOD1 (G93A) gene has greatly expanded the range of potential experiments, because the rats' large size permits biochemical analyses and therapeutic trials, such as the intrathecal injection of new drugs and stem cell transplantation. The precise nature of this disease model remains unclear. We described three disease phenotypes: the forelimb-, hindlimb-, and general-types. We also established a simple, non-invasive, and objective evaluation system using the body weight, inclined plane test, cage activity, automated motion analysis system (SCANET), and righting reflex. Moreover, we created a novel scale, the Motor score, which can be used with any phenotype and does not require special apparatuses. With these methods, we uniformly and quantitatively assessed the onset, progression, and disease duration, and clearly presented the variable clinical course of this model; disease progression after the onset was more aggressive in the forelimb-type than in the hindlimb-type. More importantly, the disease stages defined by our evaluation system correlated well with the loss of spinal motor neurons. In particular, the onset of muscle weakness coincided with the loss of approximately 50% of spinal motor neurons. This study should provide a valuable tool for future experiments to test potential ALS therapies.

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).

We investigated motoneuron degeneration after proximal nerve injury in presymptomatic transgenic (tg) rats expressing human mutant Cu/Zn superoxide dismutase (SOD1). The right facial nerves of presymptomatic tg rats expressing human H46R or G93A SOD1 and their non-tg littermates were avulsed, and facial nuclei were examined at 2 weeks postoperation. Nissl-stained cell counts revealed that facial motoneuron loss after avulsion was exacerbated in H46R- and G93A-tg rats compared with their non-tg littermates. The loss of motoneurons in G93A-tg rats after avulsion was significantly greater than that in H46R-tg rats. Intense cytoplasmic immunolabeling for SOD1 in injured motoneurons after avulsion was demonstrated in H46R- and G93A-tg rats but not in their littermates. Facial axotomy did not induce significant motoneuron loss nor enhance SOD1 immunoreactivity in these tg rats and non-tg littermates at 2 weeks postoperation, although both axotomy and avulsion elicited intense immunolabeling for activating transcription factor-3, phosphorylated c-Jun, and phosphorylated heat shock protein 27 in injured motoneurons of all these animals. The present data indicate the increased vulnerability of injured motoneurons after avulsion in the presymptomatic mutant SOD1-tg rats., ((c) 2005 Wiley-Liss, Inc.)

Approximately 20% of familial amyotrophic lateral sclerosis (FALS) arises from germ-line mutations in the superoxide dismutase-1 (SOD1) gene. However, the molecular mechanisms underlying the process have been elusive. Here, we show that a neuronal homologous to E6AP carboxyl terminus (HECT)-type ubiquitin-protein isopeptide ligase (NEDL1) physically binds translocon-associated protein-delta and also binds and ubiquitinates mutant (but not wild-type) SOD1 proportionately to the disease severity caused by that particular mutant. Immunohistochemically, NEDL1 is present in the central region of the Lewy body-like hyaline inclusions in the spinal cord ventral horn motor neurons of both FALS patients and mutant SOD1 transgenic mice. Two-hybrid screening for the physiological targets of NEDL1 has identified Dishevelled-1, one of the key transducers in the Wnt signaling pathway. Mutant SOD1 also interacted with Dishevelled-1 in the presence of NEDL1 and caused its dysfunction. Thus, our results suggest that an adverse interaction among misfolded SOD1, NEDL1, translocon-associated protein-delta, and Dishevelled-1 forms a ubiquitinated protein complex that is included in potentially cytotoxic protein aggregates and that mutually affects their functions, leading to motor neuron death in FALS.

Living cells produce reactive oxygen species (ROSs). To protect themselves from these ROSs, the cells have developed both an antioxidant system containing superoxide dismutase 1 (SOD1) and a redox system including peroxiredoxin2 (Prx2, thioredoxin peroxidase) and glutathione peroxidase1 (GPx1): SOD1 converts superoxide radicals into hydrogen peroxide (H2O2), and H2O2 is then converted into harmless water (H2O) and oxygen (O2) by Prx2 and GPx1 that directly regulate the redox system. To clarify the biological significance of the interaction of the redox system (Prx2/GPx1) with SOD1 in SOD1-mutated motor neurons in vivo, we produced an affinity-purified rabbit antibody against Prx2 and investigated the immunohistochemical localization of Prx2 and GPx1 in neuronal Lewy body-like hyaline inclusions (LBHIs) in the spinal cords of familial amyotrophic lateral sclerosis (FALS) patients with a two-base pair deletion at codon 126 and an Ala-->Val substitution at codon 4 in the SOD1 gene, as well as in transgenic rats expressing human SOD1 with H46R and G93A mutations. The LBHIs in motor neurons from the SOD1-mutated FALS patients and transgenic rats showed identical immunoreactivities for Prx2 and GPx1: the reaction product deposits with the antibodies against Prx2 and GPx1 were localized in the LBHIs. In addition, the localizations of the immunoreactivities for SOD1 and Prx2/GPx1 were similar in the inclusions: the co-aggregation of Prx2/GPx1 with SOD1 in neuronal LBHIs in mutant SOD1-related FALS patients and transgenic rats was evident. Based on the fact that Prx2/GPx1 directly regulates the redox system, such co-aggregation of Prx2/GPx1 with SOD1 in neuronal LBHIs may lead to the breakdown of the redox system itself, thereby amplifying the mutant SOD1-mediated toxicity in mutant SOD1-linked FALS patients and transgenic rats expressing human mutant SOD1.

Objective: The mechanism of spinal cord injury is believed to be related to the vulnerability of spinal motor neuron cells against ischemia. We tested whether MCI-186, which is useful for treating ischemic damage in the brain, can protect against ischemic spinal cord damage., Methods: After induction of ischemia, MCI-186 or vehicle was injected intravenously. Cell damage was analyzed by observing the function of the lower limbs and by counting the number of motor neurons. To investigate the mechanism by which MCI-186 prevents ischemic spinal cord damage, we observed the immunoreactivity of Cu/Zn superoxide dismutase, neuronal nitric oxide synthase, and endothelial nitric oxide synthase., Results: MCI-186 eased the functional deficits and increased the number of motor neurons after ischemia. The induction of neuronal nitric oxide synthase was significantly reduced by the treatment with MCI-186. Furthermore, the increase in the induction of endothelial nitric oxide synthase and Cu/Zn superoxide dismutase was more pronounced., Conclusion: These results indicate that MCI-186 may protect motor neurons from ischemic injury by reducing neuronal nitric oxide synthase and increasing endothelial nitric oxide synthase. MCI-186 may be a strong candidate for use as a therapeutic agent in the treatment of ischemic spinal cord injury.

Mutations in a Cu, Zn-superoxide dismutase (SOD1) cause motor neuron death in human familial amyotrophic lateral sclerosis (FALS) and its mouse model, suggesting that mutant SOD1 has a toxic effect on motor neurons. However, the question of how the toxic function is gained has not been answered. Here, we report that the mutant SOD1s linked to FALS, but not wild-type SOD1, aggregated in association with the endoplasmic reticulum (ER) and induced ER stress in the cDNA-transfected COS7 cells. These cells showed an aberrant intracellular localization of mitochondria and microtubules, which might lead to a functional disturbance of the cells. Motor neurons of the spinal cord in transgenic mice with a FALS-linked mutant SOD1 also showed a marked increase of GRP78/BiP, an ER-resident chaperone, just before the onset of motor symptoms. These data suggest that ER stress is involved in the pathogenesis of FALS with an SOD1 mutation.

Some cases of familial amyotrophic lateral sclerosis (ALS) are caused by mutations in the gene encoding cytosolic, copper-zinc superoxide dismutase (SOD1). 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. As in the human disease and transgenic ALS mice, pathological analysis demonstrates selective loss of motor neurons in the spinal cords of these transgenic rats. In spinal cord tissues, this is accompanied by activation of apoptotic genes known to be activated by mutant SOD1 protein in vitro and in vivo. These animals provide additional support for the proposition that motor neuron death in SOD1-related ALS reflects one or more acquired, neurotoxic properties of the mutant SOD1 protein. 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).

We identified a missense mutation of the Cu/Zn superoxide dismutase (SOD) gene (Leu126Ser) in a Japanese family with ALS that included a patient with the homozygous mutation. The content of the Cu/Zn SOD polypeptide in erythrocytes was markedly reduced in the case with the homozygous mutation compared to those with the heterozygous mutation. We speculated that this reduction of the mutant Cu/Zn SOD molecule might be related to the severe clinical phenotype of the case.

Transgenic mice that express a mutant Cu/Zn superoxide dismutase (SOD1) gene have been provided a valuable model for human amyotrophic lateral sclerosis (ALS). We studied a possible impairment of fast axonal transport in transgenic mice carrying a Gly93-->Ala (G93A) mutant SOD1 gene found in human familial ALS (FALS). Left sciatic nerve was ligated for 6 h in transgenic (Tg) and age-matched wild-type (WT) mice. Immunohistochemical analyses were performed for accumulations of kinesin and cytoplasmic dynein on both sides of the ligation site. Clinical function and histology in the spinal cords, sciatic nerves and gastrocnemius muscles were also assessed. The mice were examined at an early asymptomatic stage (aged 19 weeks) and a late stage (30 weeks) just before the development of the symptoms. WT mice showed an apparent increase in immunoreactivities for kinesin and cytoplasmic dynein at proximal and distal of the ligation, respectively. In contrast, the young Tg mice showed a selective decrease of kinesin accumulation in the proximal of the ligation. The mice were asymptomatic with a mild histological change only in muscles. The old Tg mice showed a marked reduction of the immunoreactivity for kinesin and cytoplasmic dynein on both sides of the ligation. They had a significant loss of spinal motor neurons, relatively small myelinated fiber densities of sciatic nerves, and severe muscular changes. These results provide direct evidence that the SOD1 mutation leads to impaired fast axonal transport, particularly in the anterograde direction at an early, asymptomatic stage preceding loss of spinal motor neurons and peripheral axons. This impairment may contribute to subsequent selective motor neuron death in the present model implicated for human FALS., (Copyright 1999 Elsevier Science B.V.)

1. Amyotrophic lateral sclerosis (ALS) is a degenerative disorder characterized by selective damage to the neural system that mediates voluntary movement. Although the pathophysiologic process of ALS remains unknown, about 5 to 10% of cases are familial. According to genetic linkage studies, the familial ALS (FALS) gene has been mapped on chromosome 21 in some families and recent work identified some different missense mutations in the Cu/Zn superoxide dismutase gene in FALS families. 2. We recently identified five mutations in six FALS families. The mutations identified in our FALS families are H46R, L84V, I104F, S134N, and V148I. The H46R mutation that locates in the active site of Cu/Zn SOD gene is associated with two Japanese families with very slow progression of ALS. On the other hand, the L84V mutation associated with a rapidly progressive loss of motor function with predominant lower motor neuron manifestations. 3. In the family with the V148I, the phenotype of the patient varied very much among the affected members. One case had weakness of the lower extremities at first and died without bulbar paresis. The second case first noticed wasting of the upper limbs with bulbar symptoms, but the third had weakness of upper extremities without developing dysarthria nor dysphagia until death. These mutations account for 50% of all FALS families screened, although Cu/Zn SOD gene mutations are responsible for less than about 13-21% in the Western population. 4. Our results indicate that the progression of disease with mutations of Cu/Zn SOD is well correlated with each mutation. The exact mechanism by which the abnormal Cu/Zn SOD molecules selectively affect the function of motor neurons is still unknown.

The distributions and inductions of Cu/Zn superoxide dismutase (SOD), neuronal and endothelial nitric oxide (NO) synthase (nNOS and eNOS), and nitrotyrosine (NT) were immunohistochemically examined in rabbit spinal cords after 5 and 15 min of transient ischemia. The neurons in the anterior horns (AH) were selectively lost 7 days after 15-min ischemia as compared with those of sham-operated controls. In the normal spinal cords, a number of neurons in the AHs were positive for the nNOS, and only slightly positive for the Cu/Zn SOD and the eNOS. Immunoreactivities for the proteins were induced at 8-24 h both after 5- and 15-min ischemia. In contrast, NT-like immunoreactivity was negative both in the normal and postischemic spinal cords. These results suggest that Cu/Zn SOD- and nNOS-, and eNOS-like immunoreactivities are induced, but that, even though an interaction of Cu/Zn SOD with NO could be present, NT was not detected in the motor neurons in the rabbit spinal cords after transient ischemia. Other factors could be required for NT formation found in degenerative motor neuron death in humans.

We report clinical characteristics of familial amyotrophic lateral sclerosis (FALS) with 4 different missense point mutations in exons 2, 4, and 5 of the Cu/Zn superoxide dismutase (SOD) gene, that result in amino acid substitutions of histidine46 by arginine (H46R), leucine84 by valine (L84V), isoleucine104 by phenylalanine (I104F), and valine148 by isoleucine (V148I), in 5 Japanese families. Although features of progressive neurogenic muscular atrophy were common in patients of these families, patients of each family showed characteristic clinical features. FALS patients with the H46R mutation showed a benign clinical course and stereotype progression of muscular weakness and atrophy beginning from the legs. In FALS with the L84V mutation, while the clinical course of the disease was similar, the age at onset was younger in men than women. The patients with I104F showed wide ranges of age at onset and duration with ophthalmoparesis and sensory involvement in one patient. Those with the V148I mutation showed younger age at onset and variable first symptoms within the family. Although lower motor sign was evident in all cases, hyperreflexia varied from 0 to 100% among patients with the different mutations, and the Babinski sign was not observed in any case. Bulbar palsy was frequent with I104F, but not with H46R. SOD activity of the red blood cells was severely reduced with I104F and V148I, but was slightly reduced with H46R. These results suggest that familial ALS with different mutations of the Cu/Zn SOD gene each showed clinical characteristics, and that genetic mutations and clinical features are well correlated in familial ALS.

We have identified a novel two-base mutation in exon 1 of the Cu/Zn superoxide dismutase (SOD1) gene (TGC to TTT), which resulted in Cys6 to Phe substitution in a Japanese family with amyotrophic lateral sclerosis (ALS). This is the first case of familial ALS-associated two-base change of the SOD1 gene. Similar to several mutations in exon 1 of the SOD1 gene such as Ala4 to Val, Ala4 to Thr and Val14 to Met, affected members of the present family showed a rapid progression of motor dysfunction. Although Ala4, Cys6 and Val7 reside in the middle of the first beta-strand of the SOD1, a family with a mutation of Val7 to Glu associates with slow progression of the disease. These findings suggest that clinical courses are variable with each mutation, even in the same exon.

We report a novel missense point mutation in exon 4 of the Cu/Zn superoxide dismutase (SOD) gene of affected members of a Japanese kindred segregating familial amyotrophic lateral sclerosis (FALS) through at least three successive generations. The mutation, which is predicted to cause the replacement of isoleucine at codon 104 by phenylalanine (I104F), is associated with a significant reduction in Cu/Zn SOD enzyme activity but results in a highly variable clinical phenotype. Age at onset varied from 6 to 55; the initial symptoms occurred in either the lower or upper extremities in different family members. The duration of the disease varied from 3 to 38 years. Two subjects, aged 59 and 34, remained asymptomatic until their death from other causes, although their offspring carrying the same mutation have already developed clinical evidence of the disease. These results suggest that FALS from this novel I104F mutation shows considerable clinical variation.

Although about 5 to 10% of amyotrophic lateral sclerosis (ALS) cases are familial, the pathophysiology of ALS remains unknown. A new point mutation in exon 4 of the Cu/Zn superoxide dismutase (SOD) gene, resulting in an amino acid substitution of leucine84 by valine (L84V), in a Japanese patient with familial ALS (FALS) was identified. This L84V substitution was not observed in 57 normal Japanese control subjects. The enzymatic activities of Cu/Zn SOD of skin fibroblasts were significantly reduced to 75% of the control level in the affected patient. The progression of the disease with this mutation is very rapid, but the age at onset varies with sex or generation within a family.

Pretreatment of the gerbil brain with a 2-min period of sublethal ischemia protects against neuronal damage following a subsequent 3-min period of ischemia, which normally destroys pyramidal neurons in the CA1 region of the hippocampus. To clarify the role of superoxide dismutase (SOD) in this ischemic tolerance, we immunohistochemically investigated the alterations in copper-zinc SOD (CuZnSOD) and manganese SOD (Mn-SOD) in the gerbil hippocampus following 3-min ischemia with or without the first mild ischemia. Normal hippocampus showed an intense CuZnSOD immunostaining in pyramidal neurons but relatively less MnSOD immunostaining. MnSOD, but not CuZnSOD, immunoreactivity increased after the first ischemia. Both CuZnSOD and MnSOD immunoreactivities decreased throughout the hippocampus 4 h after 3 min of ischemia both with and without the first ischemia. The immunostaining recovered in resistant regions (CA3 and dentate gyrus) after 1 day in both groups and in the pretreated CA1 after 2 days. Without pretreatment, however, the immunostaining never recovered in the vulnerable CA1 region. The results suggest that ischemic tolerance is induced in part by enhanced synthesis of MnSOD in the tolerance-acquired hippocampus. Both CuZnSOD and MnSOD immunoreactivities decreased after the second ischemia even in the pretreated hippocampus in the early reperfusion periods, but ischemic tolerance facilitated the recovery from the postischemic reductions in SOD immunoreactivity.

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurological disorder that results in relentless damage to the motor neuron system. Although about 5-10% of cases are familial, the pathophysiologic process of ALS remains unknown. We identified a novel point mutation A to G in exon 2 of the Cu/Zn SOD gene, resulting in an amino acid substitution of histidine46 by arginine (H46R), in two Japanese familial ALS (FALS) families. The segregations of the mutation were evident. The enzymatic activities of Cu/Zn SOD of peripheral red blood cell lysate were reduced to about 80% in the affected members, compared with other non-affected family members. The patients in these families are clinically characterized by relative late onset, initial involvement in lower extremities, relative rare impairment of bulbar muscles and much slow progression of muscular weakness and atrophy, compared with other Japanese FALS cases who have no mutation in the Cu/Zn SOD gene. These findings suggest that the H46R mutation in Cu/Zn SOD gene is highly related to this unique subtype of FALS.

We investigated immunohistochemically the localization and changes of manganese superoxide dismutase (Mn-SOD) in substantia nigra after 1 h of middle cerebral artery (MCA) occlusion in the rat with reperfusion periods of 1, 3, 7, and 14 days. In normal rats, Mn-SOD immunoreactivity was observed intensely in many large neurons in substantia nigra pars reticulata (SNr) and weakly in neurons in the pars compacta (SNc). The immunoreactivity of the neurons in both SNr and SNc was reduced after 1 day and almost lost 3 days after MCA occlusion, although these neurons showed completely normal morphology. The immunoreactivity recovered only in the large neurons in SNr from the 7th day and well preserved after 2 weeks, when SNr showed obvious atrophy. The results indicate that oxidative stress may be involved in the pathogenesis of the secondary postischemic neurodegeneration in SN.

We investigated immunohistochemically the localization and changes of copper/zinc superoxide dismutase (CuZn-SOD) and manganese superoxide dismutase (Mn-SOD) in the rat brain following 1 h of middle cerebral artery (MCA) occlusion. In normal brain, immunoreactivity to both SODs was observed in medium-sized neurons in the striatum and in many neurons in the neocortex. Mn-SOD was predominantly stained in cortical interneurons. The immunostaining of both SODs rapidly decreased or disappeared in neurons in the lateral segment of the striatum (ischemic center) 4 h after MCA occlusion, when the neurons were degenerating. Most neurons in the neocortex (ischemic penumbra) decreased their CuZn-SOD immunoreactivity but not Mn-SOD immunoreactivity 4 h after ischemia, when only a few neurons showed histopathological changes. CuZn-SOD immunoreactivity in almost all cortical neurons disappeared 1 day after ischemia, but Mn-SOD immunoreactivity was still preserved in interneurons, when cortical neurons showed typical pathological changes. Some cortical neurons in the boundary zone between normal and infarcted areas showed intense immunostaining to both SODs and glial SOD immunoreactivity appeared after 3 and 7 days. These results suggest that early loss of the scavenging system of free radicals may lead to neuronal damage after ischemic insult, and that induced SODs in the boundary zone between the normal and infarcted areas may act as a defense mechanism against damage.