Typical Amyotrophic Lateral Sclerosis Research Articles

Induction of COX-2-PGE2 synthesis by activation of the MAPK/ERK pathway contributes to neuronal death triggered by TDP-43-depleted microglia.

Neuroinflammation is a striking hallmark of amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders. Previous studies have shown the contribution of glial cells such as astrocytes in TDP-43-linked ALS. However, the role of microglia in TDP-43-mediated motor neuron degeneration remains poorly understood. In this study, we show that depletion of TDP-43 in microglia, but not in astrocytes, strikingly upregulates cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production through the activation of MAPK/ERK signaling and initiates neurotoxicity. Moreover, we find that administration of celecoxib, a specific COX-2 inhibitor, greatly diminishes the neurotoxicity triggered by TDP-43-depleted microglia. Taken together, our results reveal a previously unrecognized non-cell-autonomous mechanism in TDP-43-mediated neurodegeneration, identifying COX-2-PGE2 as the molecular events of microglia- but not astrocyte-initiated neurotoxicity and identifying celecoxib as a novel potential therapy for TDP-43-linked ALS and possibly other types of ALS.

Clinical varieties and epidemiological aspects of amyotrophic lateral sclerosis in the Caribbean island of Guadeloupe: A new focus of ALS associated with Parkinsonism

Our objective was to evaluate the epidemiological and clinical characteristics of amyotrophic lateral sclerosis (ALS) in the Caribbean island of Guadeloupe, using a retrospective study covering 15 years (1996–2011). Sixty-three cases of ALS were reported, with a frequency of 0.93/100,000/year. The incidence was 4.5-fold higher (3.73/100,00/year) on Marie-Galante, a small island in the Guadeloupe archipelago. ALS was associated with Parkinsonism in 23.8% of the cases. Other phenotypes were typical ALS (47.6%), bulbar forms (20.6%), limb-onset variants (6.3%) and ALS associated with frontotemporal dementia (1.6%). Onset of ALS-Parkinsonism was significantly later than in typical forms of ALS (68 vs. 54 years; p = 0.012) and affected males more frequently than did bulbar ALS (80% vs. 23.2%; p = 0.003). After one year of disease duration, the clinical profile of ALS-Parkinsonism included a symmetric akineto-rigid Parkinsonian syndrome unresponsive to levodopa, supranuclear oculomotor palsy (50%), dementia (66.7%) and signs of both lower (100%) and upper (86%) motor neuron involvement, including bulbar signs (100%). In conclusion, a new cluster of ALS-Parkinsonism and a geographical area with a high frequency of ALS were identified in Guadeloupe, suggesting that they result from environmental or genetic factors. Further studies are needed to explore these hypotheses.

CHCH10 mutations in an Italian cohort of familial and sporadic amyotrophic lateral sclerosis patients

Mutations in CHCHD10 have recently been described as a cause of frontotemporal dementia (FTD) comorbid with amyotrophic lateral sclerosis (ALS). The aim of this study was to assess the frequency and clinical characteristics of CHCHD10 mutations in Italian patients diagnosed with familial (n = 64) and apparently sporadic ALS (n = 224). Three apparently sporadic patients were found to carry c.100C>T (p.Pro34Ser) heterozygous variant in the exon 2 of CHCHD10. This mutation had been previously described in 2 unrelated French patients with FTD-ALS. However, our patients had a typical ALS, without evidence of FTD, cerebellar or extrapyramidal signs, or sensorineural deficits. We confirm that CHCHD10 mutations account for ∼1% of Italian ALS patients and are a cause of disease in subjects without dementia or other atypical clinical signs.

Pomegranate: An ideal fruit for human health

Neurodegenerative diseases, particularly mediated through increased nitroxidative stress and inflammatory cytokines, are considered to be a greatest medical challenge even for the poorly-developed world. The un-predictable onset of neurodegeneration can lead to devastating illnesses, such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic Lateral Sclerosis (ALS) and other types of dementia. Extensive research has shown that inflammatory cytokines and mitochondrial dysfunction can promote neurodegeneration, resulting in accumulation of Ab peptides in the case of Alzheimer's disease or progressive loss of dopaminergic neurons by a-synuclein mutation in the nigrostrial system in Parkinson's disease. In addition, cardiovascular disorders are among the leading causes of death and disability in the world. For instance, hypertension is a major risk factor for cardiovascular and cerebrovascular disease, end stage renal disease, type 2 diabetes, and metabolic syndrome. Similarly, cancers in many tissues including lung, breast, prostate and blood are leading causes of mortality all over the world. In addition to changes in gene expression and genetic mutations, environmental factors, drugs and dietary habits of individuals may play an important role in the onset of these neurological conditions. In the search for effective treatment and cure, the focus has recently shifted from allopathic western medicine to alternative and complementary medicine in many countries (including the United States of America). In fact, some dietary supplements including herbs, vegetables, nuts and fruits, have demonstrated promising outcomes in improving human health. Among them, pomegranate; is one of the exotic fruits that has been known for its valuable effects from the time immemorial.

Abstract A59: Deciphering the role(s) of the FET family of proteins in the Ewing sarcoma model: Is EWS-FLI-1 crashing the party?

Abstract Purpose: The EWS gene is implicated in the chromosomal translocation t(11;22)(q24;q12) that leads to the EWS/FLI-1 gene fusion, in 85% of Ewing sarcomas. EWS is a member of the FET family of proteins, which includes two other members named FUS and TAF15. FUS and TAF15 are also involved in oncogenic gene fusions. All three native proteins possess an RNA-binding domain as well as an N-terminal domain that acts as a powerful transactivation domain within the fusion protein. Mutations in the FUS gene have been associated with certain types of amyotrophic lateral sclerosis, a fatal neuro-degenerative disease. The literature indicates a role for these proteins in the modulation of gene expression. This project aims to improve understanding of the normal functions of the FET protein family, and of the impact that the EWS-FLI-1 oncogenic fusion protein may have on them, in the context of Ewing sarcoma. Methods: To elucidate their function, we have developed an efficient knock-down of the three protein-coding genes by RNA interference. We then chose to study classical processes of tumoral development and progression, as well as gene expression regulation mechanisms. Results: In Ewing and non-Ewing cell lines, we observe a decrease in live cell count after efficient simultaneous knock-down of the three proteins, as well as after knockdown of EWS or TAF15 alone. Preliminary data suggest that this phenotype might be connected to an increased cell death rather than to a cell cycle arrest. RNA-sequencing of RNA extracted in different knockdown conditions - in Ewing and non-Ewing cell lines - shows a large number of modulated transcripts both in terms of quantitative and qualitative (alternative splicing of known transcripts or novel transcripts) expression. We find a highly significant overlap between groups of transcripts that are differentially expressed after EWS, FUS or TAF15 knock-down within a given cell line, as well as between differentially expressed transcripts after same FET knockdown in two different cell backgrounds. Ingenuity-IPA analysis of transcripts at the intersection of the three FET knockdown conditions yields a significant over-representation of functions compatible with the observed phenotype such as “cell growth and proliferation”, “cell death and survival” and “cell cycle”. By crossing RNA-seq data from our Ewing cell line either after EWS or EWS-FLI-1 knockdown, we came across a small subset of 19 transcripts that were conversely regulated by EWS and EWS-FLI. This overlap allows us to hypothesize in a robust manner that EWS-FLI-1 may exert a dominant negative effect on EWS, at least in terms of regulation of gene expression. Among this subset, one target of interest is under further validation and functional assessment. Besides, we are currently validating the impact of EWS knockdown on alternative splicing of specific targets, both in Ewing and non-Ewing cells. More global aspects concerning the role of the different FET proteins in splicing and expression of alternative transcripts are currently being established. Conclusions: By deciphering the roles of the FET family of proteins in cell proliferation and regulation of gene expression, as well as how EWS-FLI-1 may disrupt them, we may identify new downstream transcripts relevant for Ewing's sarcoma biology as well as possible therapeutic targets. Citation Format: Sarah Cohen-Gogo, Franck Tirode, Olivier Delattre. Deciphering the role(s) of the FET family of proteins in the Ewing sarcoma model: Is EWS-FLI-1 crashing the party? [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A59.

Cellular and molecular mechanisms of motor neuron death in amyotrophic lateral sclerosis: a perspective.

Cellular and molecular mechanisms of motor neuron death in amyotrophic lateral sclerosis: a perspective.

The voltage‐gated calcium channel blocker lomerizine is neuroprotective in motor neurons expressing mutant SOD1, but not TDP‐43

Excitotoxicity and disruption of Ca(2+) homeostasis have been implicated in amyotrophic lateral sclerosis (ALS) and limiting Ca(2+) entry is protective in models of ALS caused by mutation of SOD1. Lomerizine, an antagonist of L- and T-type voltage-gated calcium channels and transient receptor potential channel 5 transient receptor potential channels, is well tolerated clinically, making it a potential therapeutic candidate. Lomerizine reduced glutamate excitotoxicity in cultured motor neurons by reducing the accumulation of cytoplasmic Ca(2+) and protected motor neurons against multiple measures of mutant SOD1 toxicity: Ca(2+) overload, impaired mitochondrial trafficking, mitochondrial fragmentation, formation of mutant SOD1 inclusions, and loss of viability. To assess the utility of lomerizine in other forms of ALS, calcium homeostasis was evaluated in culture models of disease because of mutations in the RNA-binding proteins transactive response DNA-binding protein 43 (TDP-43) and Fused in Sarcoma (FUS). Calcium did not play the same role in the toxicity of these mutant proteins as with mutant SOD1 and lomerizine failed to prevent cytoplasmic accumulation of mutant TDP-43, a hallmark of its pathology. These experiments point to differences in the pathogenic pathways between types of ALS and show the utility of primary culture models in comparing those mechanisms and effectiveness of therapeutic strategies.

Traumatic brain injury augments disease pathology in a mouse model of amyotrophic lateral sclerosis and wild type mice (651.11)

Traumatic Brain Injury (TBI) is a known risk factor for ALS. The goal of this study is to elucidate the mechanism linking TBI to motor neuron disease, by testing the hypothesis that TBI will accelerate disease progression in an animal model of ALS. We used a well‐characterized mouse model of familial ALS (G93A SOD1) to study the effect of TBI on ALS progression. Mice were subjected to a closed head traumatic brain injury and magnetic resonance imaging (MRI) was used 3 days after injury to characterize structural central nervous system pathology and the severity of brain injury. Histological techniques showed astrocyte infiltration (GFAP) and edema (Nissl) following mild TBI in brain and spinal cord of wildtype (WT) and transgenic mice (TG). Our results indicate that TBI leads to early reductions in grip strength and rotarod performance. Further, muscle denervation is potentiated as is shown via electromyography abnormalities. We have also characterized the effect of TBI on disease related weight loss and overall disease score in G93A mice. Our results are the first to show that TBI, in an animal model of ALS, results in significantly increased muscle denervation and brain and spinal cord pathology.Grant Funding Source: This work is supported by an individual NRSA fellowship grant, 1F31NS080508‐01

Intranuclear Aggregation of Mutant FUS/TLS as a Molecular Pathomechanism of Amyotrophic Lateral Sclerosis

Dominant mutations in FUS/TLS cause a familial form of amyotrophic lateral sclerosis (fALS), where abnormal accumulation of mutant FUS proteins in cytoplasm has been observed as a major pathological change. Many of pathogenic mutations have been shown to deteriorate the nuclear localization signal in FUS and thereby facilitate cytoplasmic mislocalization of mutant proteins. Several other mutations, however, exhibit no effects on the nuclear localization of FUS in cultured cells, and their roles in the pathomechanism of fALS remain obscure. Here, we show that a pathogenic mutation, G156E, significantly increases the propensities for aggregation of FUS in vitro and in vivo. Spontaneous in vitro formation of amyloid-like fibrillar aggregates was observed in mutant but not wild-type FUS, and notably, those fibrils functioned as efficient seeds to trigger the aggregation of wild-type protein. In addition, the G156E mutation did not disturb the nuclear localization of FUS but facilitated the formation of intranuclear inclusions in rat hippocampal neurons with significant cytotoxicity. We thus propose that intranuclear aggregation of FUS triggered by a subset of pathogenic mutations is an alternative pathomechanism of FUS-related fALS diseases.

Expression of vesicle‐associated membrane‐protein‐associated protein B cleavage products in peripheral blood leukocytes and cerebrospinal fluid of patients with sporadic amyotrophic lateral sclerosis

Vesicle-associated membrane-protein-associated protein B (VAPB) is an endoplasmic reticulum (ER) resident protein participating in ER function, vesicle trafficking, calcium homeostasis and lipid transport. Its N-terminal domain, named MSP, is cleaved and secreted, serving as an extracellular ligand. VAPB mutations are linked to autosomal-dominant motor neuron diseases, including amyotrophic lateral sclerosis (ALS) type 8. An altered VAPB function is also suspected in sporadic ALS (SALS). The expression pattern of VAPB cleavage and secreted products in the peripheral blood leukocytes (PBL) and cerebrospinal fluid (CSF) of SALS patients and neurological controls was assessed. PBL from healthy controls were also analyzed. Assays were carried out through western blotting, using an anti-VAPB (N-terminal) antibody. Two VAPB fragments containing the MSP domain (17kDa and 14kDa molecular sizes) were identified in PBL of SALS and controls, with no significant differences amongst groups. In CSF, only the 14kDa VAPB MSP fragment was expressed and a corresponding VAPA fragment was not detected. The CSF VAPB fragment was absent in 58.7% of SALS patients, of whom 79.2% were bulbar onset (P=0.001, bulbar versus spinal). The absence of the CSF VAPB MSP fragment from most bulbar-onset SALS patients suggests a specific alteration of brain-derived VAPB cleavage and secretion in this group of patients, and hints at a role of VAPB in the pathophysiology of this motor neuron disease.

Heavy metals in locus ceruleus and motor neurons in motor neuron disease

BackgroundThe causes of sporadic amyotrophic lateral sclerosis (SALS) and other types of motor neuron disease (MND) remain largely unknown. Heavy metals have long been implicated in MND, and it has recently been shown that inorganic mercury selectively enters human locus ceruleus (LC) and motor neurons. We therefore used silver nitrate autometallography (AMG) to look for AMG-stainable heavy metals (inorganic mercury and bismuth) in LC and motor neurons of 24 patients with MND (18 with SALS and 6 with familial MND) and in the LC of 24 controls.ResultsHeavy metals in neurons were found in significantly more MND patients than in controls when comparing: (1) the presence of any versus no heavy metal-containing LC neurons (MND 88%, controls 42%), (2) the median percentage of heavy metal-containing LC neurons (MND 9.5%, control 0.0%), and (3) numbers of individuals with heavy metal-containing LC neurons in the upper half of the percentage range (MND 75%, controls 25%). In MND patients, 67% of remaining spinal motor neurons contained heavy metals; smaller percentages were found in hypoglossal, nucleus ambiguus and oculomotor neurons, but none in cortical motor neurons. The majority of MND patients had heavy metals in both LC and spinal motor neurons. No glia or other neurons, including neuromelanin-containing neurons of the substantia nigra, contained stainable heavy metals.ConclusionsUptake of heavy metals by LC and lower motor neurons appears to be fairly common in humans, though heavy metal staining in the LC, most likely due to inorganic mercury, was seen significantly more often in MND patients than in controls. The LC innervates many cell types that are affected in MND, and it is possible that MND is triggered by toxicant-induced interactions between LC and motor neurons.

Protein interaction analysis of senataxin and the ALS4 L389S mutant yields insights into senataxin post-translational modification and uncovers mutant-specific binding with a brain cytoplasmic RNA-encoded peptide.

Senataxin is a large 303 kDa protein linked to neuron survival, as recessive mutations cause Ataxia with Oculomotor Apraxia type 2 (AOA2), and dominant mutations cause amyotrophic lateral sclerosis type 4 (ALS4). Senataxin contains an amino-terminal protein-interaction domain and a carboxy-terminal DNA/RNA helicase domain. In this study, we focused upon the common ALS4 mutation, L389S, by performing yeast two-hybrid screens of a human brain expression library with control senataxin or L389S senataxin as bait. Interacting clones identified from the two screens were collated, and redundant hits and false positives subtracted to yield a set of 13 protein interactors. Among these hits, we discovered a highly specific and reproducible interaction of L389S senataxin with a peptide encoded by the antisense sequence of a brain-specific non-coding RNA, known as BCYRN1. We further found that L389S senataxin interacts with other proteins containing regions of conserved homology with the BCYRN1 reverse complement-encoded peptide, suggesting that such aberrant protein interactions may contribute to L389S ALS4 disease pathogenesis. As the yeast two-hybrid screen also demonstrated senataxin self-association, we confirmed senataxin dimerization via its amino-terminal binding domain and determined that the L389S mutation does not abrogate senataxin self-association. Finally, based upon detection of interactions between senataxin and ubiquitin–SUMO pathway modification enzymes, we examined senataxin for the presence of ubiquitin and SUMO monomers, and observed this post-translational modification. Our senataxin protein interaction study reveals a number of features of senataxin biology that shed light on senataxin normal function and likely on senataxin molecular pathology in ALS4.

The epidemiology of ALS: a conspiracy of genes, environment and time

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease of motor neurons, resulting in worsening weakness of voluntary muscles until death from respiratory failure occurs after about 3 years. Although great advances have been made in our understanding of the genetic causes of ALS, the contribution of environmental factors has been more difficult to assess. Large-scale studies of the clinical patterns of ALS, individual histories preceding the onset of ALS, and the rates of ALS in different populations and groups have led to improved patient care, but have not yet revealed a replicable, definitive environmental risk factor. In this Review, we outline what is currently known of the environmental and genetic epidemiology of ALS, describe the current state of the art with respect to the different types of ALS, and explore whether ALS should be considered a single disease or a syndrome. We examine the relationship between genetic and environmental risk factors, and propose a disease model in which ALS is considered to be the result of environmental risks and time acting on a pre-existing genetic load, followed by an automatic, self-perpetuating decline to death.

Classification of sporadic lower motor neuron disease in Jeju Island

Objectives: The sporadic forms of lower motor neuron disease (LMND) constitute a heterogeneous group of diseases with largely unknown pathogenesis. Clinical, genetic, electrophysiological, and immunological findings can help to distinguish patients with LMND who never develop amyotrophic lateral sclerosis (ALS) from patients with typical ALS.

Leg Amyotrophic Diplegia

To identify the frequency of leg amyotrophic diplegia (LAD) at a US academic center, describe the pattern of weakness, and provide comparative data from 8 additional major US academic institutions. LAD is a leg onset variant of progressive muscular atrophy (PMA). LAD weakness is confined to the legs for at least 2 years, and there are no upper motor neuron signs. We present a retrospective chart review of 24 patients with the LAD presentation from the University of Kansas Medical Center ( n = 8 cases) and from 8 US academic institutions (n = 16 cases). Of the 318 subjects identified in the University of Kansas Medical Center Neuromuscular Research Database, 82% (260 subjects) had amyotrophic lateral sclerosis (ALS), 1.9% (6) had familial ALS, 6.6% (21) had primary lateral sclerosis, and 9.2% (29) had lower motor neuron (LMN) disease. Of these 29 cases, 16 had PMA, 5 had brachial amyotrophic diplegia, while 8 had LAD. The mean LAD age of onset was 58 years with a male/female ratio of 3/1. Onset was asymmetric in 7/8. We identified a pelviperoneal pattern of weakness (sparing of knee extension and/or ankle plantar flexion) in 4 cases and distal predominant weakness in 3 cases. All patients had electrodiagnostic findings consistent with motor neuron disease confined to the lower extremities. We present LAD disease duration and survival data from 8 major academic neuromuscular centers. At last follow-up, weakness progressed to involve the arms in 6/24 LAD cases and of these 6 cases, 2 patients died from progression to typical ALS. From onset of symptoms, mean survival in LAD is 87 months, with 92% of cases being alive. The natural history of LAD differs from typical forms of ALS and PMA. LAD is a slowly progressive disorder that accounts for a fourth of LMN disease cases. An asymmetric pelviperoneal pattern of weakness should heighten the suspicion for LAD.

Optineurin suppression causes neuronal cell death via NF‐κB pathway

Mutations in more than 10 genes are reported to cause familial amyotrophic lateral sclerosis (ALS). Among these genes, optineurin (OPTN) is virtually the only gene that is considered to cause classical ALS by a loss-of-function mutation. Wild-type optineurin (OPTN(WT) ) suppresses nuclear factor-kappa B (NF-κB) activity, but the ALS-causing mutant OPTN is unable to suppress NF-κB activity. Therefore, we knocked down OPTN in neuronal cells and examined the resulting NF-κB activity and phenotype. First, we confirmed the loss of the endogenous OPTN expression after siRNA treatment and found that NF-κB activity was increased in OPTN-knockdown cells. Next, we found that OPTN knockdown caused neuronal cell death. Then, overexpression of OPTN(WT) or OPTN(E) (50K) with intact NF-κB-suppressive activity, but not overexpression of ALS-related OPTN mutants, suppressed the neuronal death induced by OPTN knockdown. This neuronal cell death was inhibited by withaferin A, which selectively inhibits NF-κB activation. Lastly, involvement of the mitochondrial proapoptotic pathway was suggested for neuronal death induced by OPTN knockdown. Taken together, these results indicate that inappropriate NF-κB activation is the pathogenic mechanism underlying OPTN mutation-related ALS. Among the genes for typical amyotrophic lateral sclerosis (ALS) phenotypes, optineurin (OPTN) is virtually the only gene in which a loss-of-function mutation is considered as the principal disease mechanism. We found that OPTN knockdown induced neuronal cell death via NF-κB activation. Furthermore, proapoptotic molecules such as p53 and Bax representing downstream targets of NF-κB are suggested to be involved in neuronal death.

The ALS8 protein VAPB interacts with the ER–Golgi recycling protein YIF1A and regulates membrane delivery into dendrites

The vesicle-associated membrane protein (VAMP) associated protein B (VAPB) is an integral membrane protein localized to the endoplasmic reticulum (ER). The P56S mutation in VAPB has been linked to motor neuron degeneration in amyotrophic lateral sclerosis type 8 (ALS8) and forms ER-like inclusions in various model systems. However, the role of wild-type and mutant VAPB in neurons is poorly understood. Here, we identified Yip1-interacting factor homologue A (YIF1A) as a new VAPB binding partner and important component in the early secretory pathway. YIF1A interacts with VAPB via its transmembrane regions, recycles between the ER and Golgi and is mainly localized to the ER-Golgi intermediate compartments (ERGICs) in rat hippocampal neurons. VAPB strongly affects the distribution of YIF1A and is required for intracellular membrane trafficking into dendrites and normal dendritic morphology. When VAPB-P56S is present, YIF1A is recruited to the VAPB-P56S clusters and loses its ERGIC localization. These data suggest that both VAPB and YIF1A are important for ER-to-Golgi transport and that missorting of YIF1A may contribute to VAPB-associated motor neuron disease.

Rapidly progressive amyotrophic lateral sclerosis initially masquerading as a demyelinating neuropathy

Rare cases of demyelinating neuropathy have been described in association with amyotrophic lateral sclerosis (ALS). We report two patients with typical ALS whose initial electroneuromyographic (ENMG) presentation could suggest the existence of a process of motor nerve fiber demyelination. However, subsequent ENMG examinations and the fatal course of the disease in a few months rather supported severe ongoing axonal degeneration at the origin of motor nerve conduction abnormalities. Repeated examinations could be required to distinguish between ENMG features of concomitant demyelinating neuropathy and rapidly progressive motor neuron loss in ALS.

Deciphering amyotrophic lateral sclerosis: What phenotype, neuropathology and genetics are telling us about pathogenesis

Amyotrophic lateral sclerosis (ALS) is characterized phenotypically by progressive weakness and neuropathologically by loss of motor neurons. Phenotypically, there is marked heterogeneity. Typical ALS has mixed upper motor neuron (UMN) and lower motor neuron (LMN) involvement. Primary lateral sclerosis has predominant UMN involvement. Progressive muscular atrophy has predominant LMN involvement. Bulbar and limb ALS have predominant regional involvement. Frontotemporal dementia has significant cognitive and behavioral involvement. These phenotypes can be so distinctive that they would seem to have differing biology. However, they cannot be distinguished, at least neuropathologically or genetically. In sporadic ALS (SALS), they are mostly characterized by ubiquitinated cytoplasmic inclusions of TDP-43. In familial ALS (FALS), where phenotypes are indistinguishable from SALS and similarly heterogeneous, each mutated gene has its own genetic and molecular signature. Overall, since the same phenotypes can have multiple causes including different gene mutations, there must be multiple molecular mechanisms causing ALS − and ALS is a syndrome. Since, however, multiple phenotypes can be caused by one single gene mutation, a single molecular mechanism can cause heterogeneity. What the mechanisms are remain unknown, but active propagation of the pathology neuroanatomically seems to be a principal component. Leading candidate mechanisms include RNA processing, cell-cell interactions between neurons and non-neuronal neighbors, focal seeding from a misfolded protein that has prion-like propagation, and fatal errors introduced during neurodevelopment of the motor system. If fundamental mechanisms could be identified and understood, ALS therapy could rationally target progression and stop the disease − a goal that seems increasingly achievable.

Serum anti-neuronal antibodies in amyotrophic lateral sclerosis

We aimed to investigate various anti-neuronal antibodies in sera of amyotrophic lateral sclerosis (ALS) patients to detect possible autoimmune encephalitis patients imitating ALS findings and to delineate the validity of routine screening of well-characterized anti-neuronal antibodies in ALS. The patients fulfilling the revised El Escorial diagnostic criteria for definite ALS were included. Their serum samples were investigated for antiganglioside (IgM/IgG) and onconeural (IgG) antibodies by immunoblotting, for ion channel antibodies (IgG) by a cell-based assay and for IgG binding patterns to the rat brain by indirect immunohistochemistry. Thirty-five patients with definite ALS and 30 healthy individuals were included. Ganglioside antibodies were detected in 2 out of 35 (5.7%) patients with ALS. The onconeural and ion channel antibodies were negative in our series. Varied serum IgG binding patterns were identified in eight (22.9%) patients. Although autoimmune encephalitis patients may occasionally present with atypical motor neuron disease findings, definite ALS patients do not appear to exhibit onconeural or ion channel antibodies, suggesting that routine analysis of these antibodies in typical ALS is not mandatory. By contrast, some ALS patients display anti-neuronal antibodies against undetermined target antigens, prompting investigation of these novel antibodies with more advanced methods.