Ubiquitin-immunoreactive filamentous inclusions in anterior horn cells of Guamanian and non-Guamanian amyotrophic lateral sclerosis

Proteasome Subunits Involved in Neurodegenerative Diseases

The ubiquitin-proteasome system is the major pathway for the maintenance of protein homeostasis. Its inhibition causes accumulation of ubiquitinated proteins; this accumulation has been associated with several of the most common neurodegenerative diseases. Several genetic factors have been identified for most neurodegenerative diseases, however, most cases are considered idiopathic, thus making the study of the mechanisms of protein accumulation a relevant field of research. It is often mentioned that the biggest risk factor for neurodegenerative diseases is aging, and several groups have reported an age-related alteration of the expression of some of the 26S proteasome subunits and a reduction of its activity. Proteasome subunits interact with proteins that are known to accumulate in neurodegenerative diseases such as α-synuclein in Parkinson's, tau in Alzheimer's, and huntingtin in Huntington's diseases. These interactions have been explored for several years, but only until recently, we are beginning to understand them. In this review, we discuss the known interactions, the underlying patterns, and the phenotypes associated with the 26S proteasome subunits in the etiology and progression of neurodegenerative diseases where there is evidence of proteasome involvement. Special emphasis is made in reviewing proteasome subunits that interact with proteins known to have an age-related altered expression or to be involved in neurodegenerative diseases to explore key effectors that may trigger or augment their progression. Interestingly, while the causes of age-related reduction of some of the proteasome subunits are not known, there are specific relationships between the observed neurodegenerative disease and the affected proteasome subunits.

Novel autoantibodies against the proteasome subunit PSMA7 in amyotrophic lateral sclerosis

OBJECTIVE

To identify autoantibodies using sera from ALS patients and elucidate their roles in disease pathology.

METHODS

An immunological screening was performed with a phage expression library SEREX method using sera from 3 ALS patients to identify ALS-related autoantibodies. Levels of antibodies identified by SEREX were measured in 33 ALS patients and 30 normal controls (NCs) by AlphaLISA using recombinant non-full-length proteins. The results were then validated by ELISA using full-length proteins in 71 ALS patients, 30 NCs and 34 disease controls (DCs). The relationship between the titres and clinical profiles of ALS patients were examined.

RESULTS

Four autoantibodies identified by SEREX were proteasome subunit alpha type 7 (PSMA7), vimentin, hydroxymethylbilane synthase and TBC1 domain family member 2 (TBC1D2). AlphaLISA revealed that only the anti-PSMA7 and anti-TBC1D2 levels were significantly different between the ALS and NCs groups. ELISA showed that only the levels of antibody against PSMA7, involved in protein degradation by the ubiquitin-proteasome pathway (UPP), were higher in the ALS group than both the NC (P < .01) and DC (P = .034) groups. Anti-PSMA7 levels tended to be negatively correlated with the logarithm of disease duration (P = .052) and were significantly positively correlated with the logarithm of creatine kinase levels (P = .011). The anti-PSMA7 antibody levels were different between patients with and without dysphagia (P < .01).

CONCLUSIONS

Serum anti-PSMA7 antibody might be a disease-promoting factor in early-stage ALS and might be a biomarker of ALS. Anti-PSMA7 autoantibody might contribute to the pathogenesis of ALS, possibly via its role in the UPP.

Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration

Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.

Reactive Astrocytes Promote ALS-like Degeneration and Intracellular Protein Aggregation in Human Motor Neurons by Disrupting Autophagy through TGF-β1

Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing motor neuron disease. Astrocytic factors are known to contribute to motor neuron degeneration and death in ALS. However, the role of astrocyte in promoting motor neuron protein aggregation, a disease hallmark of ALS, remains largely unclear. Here, using culture models of human motor neurons and primary astrocytes of different genotypes (wild-type or SOD1 mutant) and reactive states (non-reactive or reactive), we show that reactive astrocytes, regardless of their genotypes, reduce motor neuron health and lead to moderate neuronal loss. After prolonged co-cultures of up to 2 months, motor neurons show increased axonal and cytoplasmic protein inclusions characteristic of ALS. Reactive astrocytes induce protein aggregation in part by releasing transforming growth factor β1 (TGF-β1), which disrupts motor neuron autophagy through the mTOR pathway. These results reveal the important contribution of reactive astrocytes in promoting aspects of ALS pathology independent of genetic influences.

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Reactive astrocytes induce ALS-like protein aggregation in human motor neurons

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Reactive astrocytes have increased secretion of TGF-β1

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TGF-β1 induces axonal and cytoplasmic protein aggregation in hMNs

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TGF-β1 activates PI3K/AKT/mTOR pathway and impairs autophagy in hMNs

Pathogenic Mechanisms in Sporadic Amyotrophic Lateral Sclerosis

In recognition of the 100th anniversary of Charcot’s death we have reviewed possible pathogenic mechanisms in amyotrophic lateral sclerosis (ALS). Advances in the last 5 years in molecular biology and genetics have identified mutations in the cytosolic dismutase (SODI) gene in some patients with familial ALS raising the possibility that oxidative stress may be involved in the pathogenesis. An excitotoxic pathogenesis has been implicated based on elevated plasma and CSF levels of amino acids and altered contents of amino acids in the nervous system of ALS patients and changes in the number of excitatory amino acid receptors. ALS sera containing antibodies to L-type calcium channels and the development of immune mediated lower and upper and lower motor neuron models have revitalized research efforts focusing on an immune basis for ALS. Other pathogenic mechanisms which have been the subject of recent research include elemental toxicity, apoptosis and programmed cell death and possibly a deficiency or abnormality in growth factors. Pathogenic processes for ALS must account for an increasing incidence of ALS, male preponderance, and the selective vulnerability of the corticomotoneuronal system.

Vapb/Amyotrophic lateral sclerosis 8 knock-in mice display slowly progressive motor behavior defects accompanying ER stress and autophagic response

Missense mutations (P56S) in Vapb are associated with autosomal dominant motor neuron diseases: amyotrophic lateral sclerosis and lower motor neuron disease. Although transgenic mice overexpressing the mutant vesicle-associated membrane protein-associated protein B (VAPB) protein with neuron-specific promoters have provided some insight into the toxic properties of the mutant proteins, their role in pathogenesis remains unclear. To identify pathological defects in animals expressing the P56S mutant VAPB protein at physiological levels in the appropriate tissues, we have generated Vapb knock-in mice replacing wild-type Vapb gene with P56S mutant Vapb gene and analyzed the resulting pathological phenotypes. Heterozygous P56S Vapb knock-in mice show mild age-dependent defects in motor behaviors as characteristic features of the disease. The homozygous P56S Vapb knock-in mice show more severe defects compared with heterozygous mice reflecting the dominant and dose-dependent effects of P56S mutation. Significantly, the knock-in mice demonstrate accumulation of P56S VAPB protein and ubiquitinated proteins in cytoplasmic inclusions, selectively in motor neurons. The mutant mice demonstrate induction of ER stress and autophagic response in motor neurons before obvious onset of behavioral defects, suggesting that these cellular biological defects might contribute to the initiation of the disease. The P56S Vapb knock-in mice could be a valuable tool to gain a better understanding of the mechanisms by which the disease arises.

Expression and cellular distribution of ubiquitin in response to injury in the developing spinal cord of Monodelphis domestica

Ubiquitin, an 8.5 kDa protein associated with the proteasome degradation pathway has been recently identified as differentially expressed in segment of cord caudal to site of injury in developing spinal cord. Here we describe ubiquitin expression and cellular distribution in spinal cord up to postnatal day P35 in control opossums (Monodelphis domestica) and in response to complete spinal transection (T10) at P7, when axonal growth through site of injury occurs, and P28 when this is no longer possible. Cords were collected 1 or 7 days after injury, with age-matched controls and segments rostral to lesion were studied. Following spinal injury ubiquitin levels (western blotting) appeared reduced compared to controls especially one day after injury at P28. In contrast, after injury mRNA expression (qRT-PCR) was slightly increased at P7 but decreased at P28. Changes in isoelectric point of separated ubiquitin indicated possible post-translational modifications. Cellular distribution demonstrated a developmental shift between earliest (P8) and latest (P35) ages examined, from a predominantly cytoplasmic immunoreactivity to a nuclear expression; staining level and shift to nuclear staining was more pronounced following injury, except 7 days after transection at P28. After injury at P7 immunostaining increased in neurons and additionally in oligodendrocytes at P28. Mass spectrometry showed two ubiquitin bands; the heavier was identified as a fusion product, likely to be an ubiquitin precursor. Apparent changes in ubiquitin expression and cellular distribution in development and response to spinal injury suggest an intricate regulatory system that modulates these responses which, when better understood, may lead to potential therapeutic targets.

An immunohistochemical study of ubiquitin in the skin of sporadic amyotrophic lateral sclerosis

Ubiquitin (UB)-immunoreactive filamentous inclusions, absent in normal cases and in any other disorder, have been found in patients with amyotrophic lateral sclerosis (ALS) and it has been suggested that they may be characteristic of this disorder. However, there has been no study of UB in ALS skin. We made a quantitative immunohistochemical study of the expression of UB in the skin from 19 patients with sporadic ALS and 19 control subjects. The proportion of UB-positive (UB+) cells in the epidermis in ALS patients was significantly higher (p<0.001) than in controls. There was a significant positive relationship (r=0.92, p<0.001) between the proportion and duration of illness in ALS patients. The optical density of UB+ cells in the epidermis in ALS patients is markedly stronger (p<0.001) than in controls. There was a significant positive relation (r=0.58, p<0.01) between the immunoreactivity and duration of illness in ALS patients. These data suggest that changes of UB in ALS skin are related to the disease process and that metabolic alterations of UB may take place in the skin of patients with ALS.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive muscular paralysis reflecting degeneration of motor neurones in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Incidence (average 1.89 per 100,000/year) and prevalence (average 5.2 per 100,000) are relatively uniform in Western countries, although foci of higher frequency occur in the Western Pacific. The mean age of onset for sporadic ALS is about 60 years. Overall, there is a slight male prevalence (M:F ratio approximately 1.5:1). Approximately two thirds of patients with typical ALS have a spinal form of the disease (limb onset) and present with symptoms related to focal muscle weakness and wasting, where the symptoms may start either distally or proximally in the upper and lower limbs. Gradually, spasticity may develop in the weakened atrophic limbs, affecting manual dexterity and gait. Patients with bulbar onset ALS usually present with dysarthria and dysphagia for solid or liquids, and limbs symptoms can develop almost simultaneously with bulbar symptoms, and in the vast majority of cases will occur within 1-2 years. Paralysis is progressive and leads to death due to respiratory failure within 2-3 years for bulbar onset cases and 3-5 years for limb onset ALS cases. Most ALS cases are sporadic but 5-10% of cases are familial, and of these 20% have a mutation of the SOD1 gene and about 2-5% have mutations of the TARDBP (TDP-43) gene. Two percent of apparently sporadic patients have SOD1 mutations, and TARDBP mutations also occur in sporadic cases. The diagnosis is based on clinical history, examination, electromyography, and exclusion of 'ALS-mimics' (e.g. cervical spondylotic myelopathies, multifocal motor neuropathy, Kennedy's disease) by appropriate investigations. The pathological hallmarks comprise loss of motor neurones with intraneuronal ubiquitin-immunoreactive inclusions in upper motor neurones and TDP-43 immunoreactive inclusions in degenerating lower motor neurones. Signs of upper motor neurone and lower motor neurone damage not explained by any other disease process are suggestive of ALS. The management of ALS is supportive, palliative, and multidisciplinary. Non-invasive ventilation prolongs survival and improves quality of life. Riluzole is the only drug that has been shown to extend survival.

The contribution of mitochondrial dysfunction to a gene-environment model of Guamanian ALS and PD

Scientific investigations of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD) of Guam have implicated genetic and environmental risk factors in their etiology. Using brain tissue, we investigated mitochondrial dysfunction and report a higher frequency of somatic mutations in the light strand promoter (LSP) of the mitochondrial control region in Guam ALS and PD patients than in Guam controls, along with the presence of inherited mutations that may contribute to a novel gene-environment interaction risk model. Along with other risk factors, they demonstrate both the importance and significance of genetic and environmental contributions to Guam ALS and PD etiology.

Amyotrophic lateral sclerosis with dementia: an autopsy case showing many Bunina bodies, tau-positive neuronal and astrocytic plaque-like pathologies, and pallido-nigral degeneration

We report the case of a 54-year-old woman with mental retardation who developed frontotemporal dementia and amyotrophic lateral sclerosis (ALS) in the presenium. She presented with dementia at age 48, and motor neuron signs developed at age 53. She had no family history of dementia or ALS. Postmortem examination disclosed histopathological features of ALS, including pyramidal tract degeneration, mild loss of motor neurons, and many Bunina bodies immunoreactive for cystatin C, but not ubiquitin-positive inclusions. Unusual features of this case included severe neuronal loss in the substantia nigra and medial globus pallidus. The subthalamic nucleus, limbic system, and cerebral cortex were well preserved. In addition, neurofibrillary tangles (NFTs) were found in the frontal, temporal, insular, and cingulate cortices, nucleus basalis of Meynert, and locus coeruleus, and to a lesser degree, in the dentate nucleus, cerebellum, hippocampus, and amygdala. No ballooned neurons, tufted astrocytes, or astrocytic plaques were found. Tau immunostaining demonstrated many pretangles rather than NFTs and glial lesions resembling astrocytic plaques in the frontal and temporal cortices. This glial tau pathology predominantly developed in the middle to deep layers in the primary motor cortex, and was frequently associated with the walls of blood vessels. NFTs were immunolabeled with 3-repeat and 4-repeat specific antibodies against tau, respectively. Although the pathophysiological relationship between tau pathology and the selective involvement of motor neurons, substantia nigra, and globus pallidus was unclear, we considered that it might be more than coincidental.

Pathogenic Lrrk2 substitutions and Amyotrophic lateral sclerosis

Pathogenic Lrrk2 Y1699C substitution observed in a large German-Canadian kindred presents a neurodegenerative disorder that is reminiscent of amyotrophic lateral sclerosis and Parkinsonism-Dementia Complex. We screened 54 patients with ALS for seven known Lrrk2 pathogenic substitutions in the Roc, COR and kinase domains. No mutations were observed suggesting that this locus does not have a major influence on the ALS phenotype. However we can not rule out other genetic variation at the LRRK2 locus may play a role in parkinsonian disorders with amyotrophic lateral sclerosis and may be considered candidates for genetic screening.

Return of the cycad hypothesis - does the amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) of Guam have new implications for global health?

Recently published work provides evidence in support of the cycad hypothesis for Lytico--Bodig, the Guamanian amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC), based on a new understanding of Chamorro food practices, a cyanobacterial origin of beta-methylaminoalanine (BMAA) in cycad tissue, and a possible mechanism of biomagnification of this neurotoxic amino acid in the food chain. BMAA is one of two cycad chemicals with known neurotoxic properties (the other is cycasin, a proven developmental neurotoxin) among the many substances that exist in these highly poisonous plants, the seeds of which are used by Chamorros for food and medicine. The traditional diet includes the fruit bat, a species that feeds on cycad seed components and reportedly bioaccumulates BMAA. Plant and animal proteins provide a previously unrecognized reservoir for the slow release of this toxin. BMAA is reported in the brain tissue of Guam patients and early data suggest that some Northern American patients dying of Alzheimer's disease (AD) have detectable brain levels of BMAA. The possible role of cyanobacterial toxicity in sporadic neurodegenerative disease is therefore worthy of consideration. Recent neuropathology studies of ALS/PDC confirm understanding of this disorder as a 'tangle' disease, based on variable anatomical burden, and showing biochemical characteristics of 'AD-like' combined 3R and 4R tau species. This model mirrors the emerging view that other neurodegenerative disease spectra comprise clusters of related syndromes, owing to common molecular pathology, with variable anatomical distribution in the nervous system giving rise to different clinical phenotypes. Evidence for 'ubiquitin-only' inclusions in ALS/PDC is weak. Similarly, although there is evidence for alpha-synucleinopathy in ALS/PDC, the parkinsonian component of the disease is not caused by Lewy body disease. The spectrum of sporadic AD includes involvement of the substantia nigra and a high prevalence of 'incidental'alpha-synucleinopathy in sporadic AD is reported. Therefore the pathogenesis of Lytico-Bodig appears still to have most pertinence to the ongoing investigation of the pathogenesis of AD and other tauopathies.

Tau protein concentrations in cerebrospinal fluid of patients with amyotrophic lateral sclerosis

OBJECTIVE

To elucidate whether cerebrospinal fluid (CSF) concentrations of the microtubule-associated tau protein are related to the risk for sporadic amyotrophic lateral sclerosis (SALS).

PATIENTS/METHODS

We measured tau concentrations in the CSF of 18 patients with SALS and 75 age- and sex-matched controls, using a specific ELISA method.

RESULTS

The mean CSF concentrations of tau protein did not differ significantly between SALS patient and control groups, were not influenced by the clinical form (spinal vs bulbar) of ALS, and were not correlated with age, age at onset, and duration of the disease.

CONCLUSIONS

CSF tau concentrations are not a biochemical marker of ALS.

Fibrillar inclusions and motor neuron degeneration in transgenic mice expressing superoxide dismutase 1 with a disrupted copper-binding site

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.

Spinal cord neurofibrillary pathology in Alzheimer disease and Guam Parkinsonism-dementia complex

We examined spinal cords of neurodegenerative disease patients and controls living on the Island of Guam and in the continental United States. These patients had pathologically confirmed parkinsonism dementia-complex (PDC) with or without amyotrophic lateral sclerosis (ALS), or Alzheimer disease (AD), respectively. Nearly all of the spinal cords examined from both groups of patients contained neurofibrillary tangles (NFT). The immunohistochemical profile of these NFTs indicates that they are composed of hyperphosphorylated tau protein like their counterparts in the brains of these patients. Western blot analysis confirmed this by revealing that sarcosyl insoluble tau in spinal cord extracts from patients with NFTs exhibited the presence of all 6 tau isoforms similar to that from AD and ALS/PDC cortical gray matter.

Tau epitopes in spinal cord neurofibrillary lesions in Chamorros of Guam

We examined spinal cord sections from Guamanian Chamorros with or without amyotrophic lateral sclerosis or parkinsonism-dementia complex using immunohistochemistry and antibodies to epitopes that span the length of tau to characterize the tau epitope profile of neurofibrillary tangles in these spinal cords. Most (16/20) spinal cords, including some from Chamorros without documented clinical disease, contained tangles with a tau epitope profile similar to the tangles found in the forebrain and brain stem of these patients.

Transgenic mouse models of Alzheimer's disease and amyotrophic lateral sclerosis

Over the past several years, there has been enormous progress in generating transgenic mice that model aspects of human neurodegenerative diseases. These studies build upon the efforts of molecular geneticists who have identified a number of genes that, when mutated, cause familial forms of these diseases. In this review, we focus on the mutations that cause familial forms of Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), and transgenic mouse models that develop clinical and pathological abnormalities resembling those occurring in the human diseases.

Motor neuron disease with neurofibrillary tangles in a non-Guamanian patient

Neurofibrillary tangles are described in Guamanian and post-encephalitic forms of motor neuron disease (MND) but not in sporadic MND. We report the neuropathological findings in a 79-year-old man who died after a 1-year history of MND without extrapyramidal features or dementia. There was no family history of neurological disease and he had not visited Guam. The spinal cord showed loss of anterior horn cells, and skeletal muscle typical changes of denervation. The brain appeared macroscopically normal but histology revealed many neurofibrillary tangles, particularly in medial temporal lobe structures, insula, nucleus basalis, hippocampus, oculomotor nucleus, raphe nuclei and locus ceruleus. Neurofibrillary tangles were not seen in the primary motor cortex, which appeared histologically unremarkable. Occasional tangles were present in the substantia nigra and pontine nuclei. None were seen in the cerebellum, medulla or spinal cord. The tangles were argyrophilic, and, in sections stained with thioflavin-S, both the intracellular and the extracellular tangles fluoresced strongly under ultraviolet light. The intracellular neurofibrillary tangles reacted strongly with an antibody to tau protein, and only occasional tangles showed weak ubiquitin immunoreactivity. Scattered neuropil threads were present in the cortex in the areas of neurofibrillary tangle formation. No plaques were present in any part of the brain and no A4/beta protein immunoreactivity was detected. Ultrastructural examination revealed Alzheimer-type neurofibrillary tangles composed of paired helical filaments. The present findings further extend the spectrum of diverse neurological disorders associated with neurofibrillary tangles.

Reversibility of neurofilamentous inclusion formation following repeated sublethal intracisternal inoculums of AlCl3 in New Zealand white rabbits

In this report, we describe the clinical, topographical and immunohistochemical characteristics of neurofilament (NF) inclusion formation induced by the intracisternal inoculation of young adult New Zealand white rabbits at 28-day intervals with 100 micrograms AlCl3 over the course of 267 days. The ability to recover following cessation of aluminum exposure has also been assessed. The extent of neurofilamentous inclusion formation was proportionate to the cumulative amount of AlCl3 inoculated and initially consisted of fusiform axonal distention in the ventral spinal cord at day 51 following the initial inoculum. Spinal motor neuron perikaryal inclusions and discrete axonal spheroids were observed at day 107 and supraspinal neurofilamentous pathology by day 156. Perikaryal inclusions were immunoreactive to antibodies recognizing both poorly phosphorylated (SMI 32) and more highly phosphorylated high molecular weight NF (NFH). In contrast, axonal spheroids were intensely immunoreactive at all stages with antibodies recognizing highly phosphorylated NFH and an age-dependent NFH phosphorylation state (SMI 34) with only faint SMI 32 immunoreactivity. Immunoreactivity to an antibody recognizing ubiquitin-protein conjugates did not appear until day 156, whereas inclusions were not immunoreactive to antibodies recognizing either phosphatase-dependent or -independent microtubule-associated protein tau at any stage. Upon withdrawal from further AlCl3 exposure after intervals of 51, 107 or 156 days following the initial inoculum, clinical recovery ensued in all rabbits. In all but the most severely affected rabbits, perikaryal neurofilamentous inclusions resolved. However, axonal spheroids continued to be prominent. These studies demonstrate that the repetitive intracisternal inoculation of AlCl3 in New Zealand white rabbits induces a reversible process of neurofilamentous inclusion formation that preferentially affects motor neurons, and in which recovery will occur in those inclusions containing an admixture of both poorly and highly phosphorylated NFH.

Concurrence of Alzheimer's disease, Parkinson's disease, diffuse Lewy body disease, and amyotrophic lateral sclerosis

A 71-year-old man developed signs of progressive dementia, followed by extrapyramidal and motor neuron disease symptoms, which led to death in 6 years. Neuropathological examination revealed neuritic plaques, neurofibrillary tangles, and Lewy bodies in the substantia nigra and neocortex. Atrophy and gliosis with intraneuronal ubiquitin inclusions were present in the anterior horns of the spinal cord. Overlapping of Alzheimer's disease, Parkinson's disease, diffuse Lewy body disease and amyotrophic lateral sclerosis is rare and can increase our understanding of the process of neurodegeneration.

Topographic involvement of the striatal efferents in basal ganglia of patients with adult-onset motor neuron disease with basophilic inclusions

This report concerns the topographic immunohistochemical analysis of the putamen, globus pallidus (GP) and substantia nigra (SN) of two patients with adult-onset motor neuron disease with basophilic inclusions (MND/BIs), seven patients with sporadic classic amyotrophic lateral sclerosis (sporadic ALS) and five neurologically normal individuals. The striatal efferent terminals of the GP and SN were visualized immunohistochemically using antibodies to met-enkephalin (MEnk) and substance P (SP). In specimens from patients with sporadic ALS and normal subjects there was intense immunostaining for MEnk and SP throughout the external and internal segments of the GP, respectively. By contrast, a marked reduction of MEnk- and SP-positive striatal efferents was seen in the ventrocaudal portions of both GP segments from the MND/BIs patients. Moreover, while MEnk-positive striosomes was readily detected in the putamen of normals and sporadic ALS patients, there was significant reduction in MEnk immunoreactivity, and no evidence of striosomal organization in the putamen of MND/BIs patients. In addition, whereas the SN of patients with sporadic ALS expressed SP, the ventrolateral SN portion of the MND/BIs patient tested had reduced immunoreactivity. The present findings on patients with MND/BIs may represent a reflection of the topographic striatum degeneration in this disease and appear to provide additional evidence for the heterogeneity of MND.

Amyotrophic lateral sclerosis of Guam: the nature of the neuropathological findings

To elucidate the fundamental differences and similarities of the neuropathological features and etiopathogenesis of the amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) of Guam, we conducted a topographic, quantitative and histological investigation of tau-containing neurons, neurofibrillary tangles (NFTs), Bunina bodies and ubiquitinated inclusion bodies in 27 non-ALS non-PDC Guamanian subjects, as well as 10 Guam ALS patients, 28 PDC patients, and 5 patients with combined ALS and PDC (ALS-PDC). The topographic distribution of NFTs was basically the same in each disease and also in the non-ALS non-PDC group. There were relatively few, if any, NFTs in non-ALS non-PDC subjects and ALS patients, but there were many, especially in the frontal and temporal cortex, in Guam PDC and ALS-PDC patients. The histological and ultrastructural features of Bunina bodies in Guam ALS and ALS-PDC patients were similar to those reported in classic ALS. The ratio of occurrence of the inclusion in Guam ALS and ALS-PDC patients was similar to that reported so far in classic ALS. Ubiquitinated skein-like inclusion bodies were observed in the spinal anterior horn cells in Guam ALS and ALS-PDC patients. These findings indicate that classic ALS does exist on Guam, that NFTs in Guam ALS patients are merely a background feature widely dispersed in the population, that the mechanism of neuronal degeneration of Guam ALS is basically different from that of PDC, and that Guam ALS occurs initially are classic ALS.

Aluminum neurotoxicity: an experimental approach to the induction of neurofilamentous inclusions

Acute or chronic aluminum neurotoxicity experiments in the rabbit suggest that aluminum can induce phosphorylation of neurofilamentous proteins. This may result in abnormal resistance to degradation or transport of neurofilament protein and so to the accumulation of neurofilaments in abnormal cells. The possible importance of this process in ALS is considered in relation to the neurofilamentous abnormalities characteristic of intraneuronal inclusions in ALS and in other neurodegenerative disorders.

New pathological findings in amyotrophic lateral sclerosis

There have been recent developments in the pathology of sporadic ALS. A new filamentous neuronal inclusion body in ALS detected by immunohistochemical localisation of the protein ubiquitin has been characterised at the light microscopic and ultrastructural level and appears specific for the disease. The molecular composition of underlying filaments remains unresolved but the quest for this is a major aim in ALS research. Despite being a progressive degenerative process which primarily affects motor systems, ALS is now recognised to involve several non-motor systems and in long survivors affects many subcortical structures. There is also accumulating evidence that the neurodegenerative process underlying ALS may present as a non-motor clinical syndrome, particularly as a frontal lobe dementia with characteristic inclusions present in the non-motor cortex. Considering ALS as a multisystem disease rather than simply a disease of motor neurones has major implications for research into pathogenesis.

Comparative study of spinal cord ubiquitin expression in post-poliomyelitis and sporadic amyotrophic lateral sclerosis

This study addresses the suggested possible pathogenetic relationship between the late-onset muscular atrophy in patients with the prior diagnosis of poliomyelitis and amyotrophic lateral sclerosis (ALS). For this purpose we applied immunohistochemical techniques to determine the presence of pathological structures that were stained for ubiquitin (a protein involved in degenerative processes) in the spinal cords of patients with a history of poliomyelitis and compared the results with those of ALS, a condition in which cytoplasmic ubiquitin-positive inclusions are invariably found in the anterior horn cells. Our results indicate that post-poliomyelitis patients have no ubiquitin-reactive inclusion bodies in these cells; however, some immunopositive globular and cord-shaped structures are seen in less-affected areas. Similar structures were also found in the spinal cords from patients with ALS and from normal individuals. Our findings would suggest that the pathogenesis of late muscular atrophy in post-poliomyelitis patients is dissimilar to that of ALS.

Ubiquitin-positive inclusion in anterior horn cells in subgroups of motor neuron diseases: a comparative study of adult-onset amyotrophic lateral sclerosis, juvenile amyotrophic lateral sclerosis and Werdnig-Hoffmann disease

This report concerns the expression of ubiquitin in anterior horn cells of various subgroups of adult and infantile motor neuron disease (MNDs); immunohistochemical techniques were employed. Ubiquitin-positive skein-like inclusions (SLIs) were found in all cases of adult-onset amyotrophic lateral sclerosis (ALS), including 16 cases with sporadic ALS, two cases of familial ALS with posterior column degeneration and Lewy body-like hyaline inclusions (LBHIs), two sporadic ALS cases with LBHIs, and three cases of sporadic ALS with dementia. SLIs were not found in anterior horn cells of 5 cases with Werdnig-Hoffmann disease (WHD). However, granular ubiquitin-positive deposits were seen in ballooned neurons of WHD patients. No ubiquitinated materials were found in the perikarya of two sporadic juvenile ALS patients with basophilic inclusions (BIs), but granular ubiquitin-immunoreactive deposits were occasionally observed in the BIs. These results suggest that ubiquitin-positive SLIs are characteristic features of various forms of adult-onset ALS and that aggregated ubiquitinated granules are characteristic of ballooned neurons of WHD. Ubiquitinated structures and their distribution patterns may reflect degenerative processes of anterior horn cells, and may be useful for classifying subgroups of motor neuron diseases.

Ubiquitin in neurodegenerative diseases

Immunochemical staining to detect ubiquitin has become an essential technique in evaluating neurodegenerative processes. Age related staining is seen in myelin, in nerve processes in lysosome-related dense bodies, and in corpora amylacea. There is a constant association between filamentous inclusions and the presence of ubiquitin. Intermediate filaments associated with ubiquitin, alpha B crystallin and enzymes of the ubiquitin pathway are the basis of Lewy bodies and Rosenthal fibres, as well as related bodies outside the nervous system. Neurofibrillary tangles in diverse diseases are associated with ubiquitin as are several other tau containing inclusions in both neurones and glia. Inclusions in motor neurones and non-motor cortex characterizing amyotrophic lateral sclerosis (ALS) and certain related forms of frontal lobe dementia can only be readily detected by anti-ubiquitin. Anti-ubiquitin also identifies both filamentous and lysosomal structures in neuronal processes as well as in some swollen neurones. Involvement of ubiquitin-containing elements of the lysosomal system appears important in pathogenesis of prion encephalopathies. Despite great advances in understanding cell biology of the ubiquitin pathway there are as yet few insights into the precise role played by ubiquitin in neuronal disease.

Ultrastructural study of skein-like inclusions in anterior horn neurons of patients with motor neuron disease

We investigated the ultrastructure of skein-like inclusions (SI) in 11 patients with motor neuron disease. SI mainly consisted of bundles of filaments. Each filament was approximately 15-25 nm in diameter and had a tubular profile on transverse sections. SI occasionally appeared to contain electron-dense material similar to Bunina bodies (BB), and in clusters of SI, electron-dense material closely resembling BB with vesicles were scattered among the bundles of filaments or were directly attached to the filaments, suggesting a close relationship between SI and BB. We also infer that SI might be the precursor of Lewy body-like hyaline inclusions (LBHI), on the basis of the frequent presence of in-between structures, the coexistence of SI and LBHI, the detection of tubular profiles (component of SI) in LBHI, the far greater frequency with which SI were observed compared with LBHI, and the occasional connection between ubiquitin-positive SI and LBHI observed in preceding immunocytochemical studies.

Morphometry of spinal motor neurons in amyotrophic lateral sclerosis with special reference to chromatolysis and intracytoplasmic inclusion bodies

Lewy body-like hyaline inclusions (LBI), Bunina bodies (BB) and central chromatolysis are characteristic neuropathological features of spinal motor neurons in amyotrophic lateral sclerosis (ALS). Using histometric methods, we studied the spinal motor neurons of 4 patients with sporadic ALS and 3 neurological control patients to determine the possible relationship between these neuropathological features and cytoplasmic, nuclear and nucleolar size. In an ALS patient with a very rapid clinical course, many neurons with LBI were observed. Enlargement of nucleolar size and the nucleolar/nuclear ratio of neurons with LBI or BB were the only histometric difference compared to those of normal-appearing neurons. In ALS patients with an average clinical course, the number of neurons with LBI was lower, the number of neurons with BB was higher, and the nuclear and nucleolar sizes were smaller than those of normal-appearing neurons, particularly in chromatolytic neurons without LBI or BB. These data raise the possibility that motor neurons with LBI may represent an early stage in the neurodegenerative process, when the rate of protein synthesis is elevated as evidenced by their larger nucleolar size. Thus, the causative agent(s) of ALS may initially stimulate protein synthesis while in turn leading to down regulation of certain luxury function genes, culminating in neuronal dysfunction and death.

Basophilic inclusions in sporadic juvenile amyotrophic lateral sclerosis: an immunocytochemical and ultrastructural study

This report concerns immunocytochemical and ultrastructural studies on the basophilic inclusions in two cases of sporadic juvenile amyotrophic lateral sclerosis (ALS). The inclusion had a globular, irregular-shaped, or sometimes fragmented appearance. Ultra-structurally, the inclusions consisted mainly of thick filamentous structures associated with granules. Focal neurofilamentous accumulations were occasionally observed among the granulofilamentous structures. The basophilic inclusions occasionally showed granular reaction product deposits with an antibody to ubiquitin. The inclusions did not react with antibodies to phosphorylated neurofilament and to tau protein.

Motor cortex involvement in presenile dementia: report of a case

Alzheimer's disease (AD) is characterized neuropathologically by high densities of neurofibrillary tangles (NFT) and neuritic plaques (NP) in the cerebral cortex, in particular in neocortical association areas and in the hippocampal formation. We report here the case of an AD patient who developed signs of motor dysfunction early in the clinical evolution. A quantitative neuropathologic analysis revealed much higher densities of NFT and NP in the primary motor cortex than is usually observed in AD. This case, together with other reports, points to the existence of neurologically defined subgroups of AD with unusual clinical deficits that are correlated with the regional and laminar distribution of NP and NFT, and further supports the hypothesis that the symptomatology presented by AD patients results from the loss of specific neuronal populations leading to a syndrome of global cortical disconnection.

Skein-like inclusions in the anterior horn cells in motor neuron disease

Skein-like inclusions (SLIs) in the anterior horn cells of patients with motor neuron diseases, including familial amyotrophic lateral sclerosis with posterior column degeneration, sporadic lower motor neuron disease and classical amyotrophic lateral sclerosis, were investigated morphologically with hematoxylin and eosin preparations, immunostaining for ubiquitin and immunoelectron microscopy. The SLIs were thready linear or tubular structures which immunostained with antiubiquitin antibodies. They were detected on hematoxylin and eosin preparations as eosinophilic thread-like structures often surrounded by pale areas. SLIs were occasionally present as networks of threads or tubules. Sometimes, they were aggregated and formed larger pale inclusions. Ultrastructurally, the SLIs were bundles of filaments which appeared thicker than neurofilaments. The SLIs tended to have central hollow spaces which were devoid of filaments. When the SLIs were clustered, fuzzy thick filaments were randomly and loosely arranged among the individual SLIs. The SLIs were histologically and ultrastructurally distinct from other inclusions such as Bunina bodies and hyaline inclusions. This unique morphology of SLIs may provide a novel perspective on the degenerative processes of the anterior horn cells in MND.

Light and electron microscopic and immunohistochemical observations of the Onuf's nucleus of amyotrophic lateral sclerosis

We examined the Onufrowicz nucleus (Onuf's nucleus) of ten sporadic amyotrophic lateral sclerosis (ALS) patients with light and electron microscopic and immunohistochemical methods. Neurons in the Onuf's nucleus of ALS patients were better preserved than those in anterior horn cells. However, some showed morphological changes in the nucleus, namely, central chromatolytic changes, Bunina bodies, ubiquitin-positive filaments and spheroids. The Onuf's neurons of ALS patients showed more argentophilia than those of non-ALS patients. Electron microscopic observations revealed that neurofilaments were relatively more numerous in the Onuf's neurons of ALS patients. Bunina bodies and degenerated neurites were also seen in the Onuf's nucleus. In conclusion, the Onuf's nucleus in sporadic ALS patients showed some morphological changes similar to those noted in anterior horn cells.