Typical Amyotrophic Lateral Sclerosis Research Articles

Clinical findings in amyotrophic lateral sclerosis type 4 (S54.003)

Clinical findings in amyotrophic lateral sclerosis type 4 (S54.003)

Retinoic acid worsens ATG10-dependent autophagy impairment in TBK1-mutant hiPSC-derived motoneurons through SQSTM1/p62 accumulation

ABSTRACT Mutations in the TBK1 (TANK binding kinase 1) gene are causally linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TBK1 phosphorylates the cargo receptors OPTN and SQSTM1 regulating a critical step in macroautophagy/autophagy. Disruption of the autophagic flux leads to accumulation of cytosolic protein aggregates, which are a hallmark of ALS. hiPSC-derived TBK1-mutant motoneurons (MNs) showed reduced TBK1 levels and accumulation of cytosolic SQSTM1-positive aggresomes. By screening a library of nuclear-receptor-agonists for modifiers of the SQSTM1 aggregates, we identified 4-hydroxy(phenyl)retinamide (4HPR) as a potent modifier exerting detrimental effects on mutant-TBK1 motoneurons fitness exacerbating the autophagy overload. We have shown by TEM that TBK1-mutant motoneurons accumulate immature phagophores due a failure in the elongation phase, and 4HPR further worsens the burden of dysfunctional phagophores. 4HPR-increased toxicity was associated with the upregulation of SQSTM1 in a context of strongly reduced ATG10, while rescue of ATG10 levels abolished 4HPR toxicity. Finally, we showed that 4HPR leads to a downregulation of ATG10 and to an accumulation of SQSTM1+ aggresomes also in hiPSC-derived C9orf72-mutant motoneurons. Our data show that cultured human motoneurons harboring mutations in TBK1 gene display typical ALS features, like decreased viability and accumulation of cytosolic SQSTM1-positive aggresomes. The retinoid 4HPR appears a strong negative modifier of the fitness of TBK1 and C9orf72-mutant MNs, through a pathway converging on the mismatch of initiated autophagy and ATG10 levels. Thus, autophagy induction appears not to be a therapeutic strategy for ALS unless the specific underlying pathway alterations are properly addressed. Abbreviations 4HPR: 4-hydroxy(phenyl)retinamide; AKT: AKT1 serine/threonine kinase 1; ALS: amyotrophic lateral sclerosis; ATG: autophagy related; AVs: autophagic vesicle; C9orf72: chromosome 9 open reading frame 72; CASP3: caspase 3; CHAT: choline O-acetyltransferase; CYCS: cytochrome c, somatic; DIV: day in vitro; FTD: frontotemporal dementia; FUS: FUS RNA binding protein; GFP: green fluorescent protein; hiPSCs: human induced pluripotent stem cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MNs: motoneurons; mRFP: monomeric red fluorescent protein; MTOR: mechanistic target of rapamycin kinase; NFE2L2/NRF2: nuclear factor, erythroid 2 like 2; RARA: retinoic acid receptor alpha; SLC18A3/VACHT: solute carrier family 18 (vesicular acetylcholine transporter), member 3; SQSTM1/p62: sequestosome 1; TBK1: TANK binding kinase 1; TEM: transmission electron microscopy

Inhibition of the Rho‐kinase (ROCK) pathway improves morphology and stress granule formation in ALS4 patient iPSC‐derived motor neurons

Amyotrophic lateral sclerosis type 4 (ALS4) is an autosomal dominant motor neuron disorder caused by mutation in the senataxin gene (SETX), which is associated with upregulation of the TGFβ signaling pathway. ALS4 is characterized by early onset motor weakness, with distal muscle predominance and slow progression. The mechanism by which TGFβ pathway disruption may lead to degeneration of motor neurons is not clear. We used patient‐derived iPSC‐motor neurons to study the neuronal phenotype of ALS4. After 7 days of differentiation, ALS4 patient motor neuron‐like cells were found to have less morphological complexity, as defined by fewer branch points per soma and shorter axonal lengths, and this was reversed with Rho‐kinase inhibitor (RI) treatment. Morphological characterization was done using in vitro live cell imaging. In addition, stress granule formation, as quantified by immunofluorescence staining with G3BP antibody, was increased in ALS4 cells compared to controls. Analysis was done after 7 days of motor neuron differentiation. In summary, these results suggest that Rho‐kinase pathway inhibition can rescue abnormal morphological features in ALS4 patient‐derived motor neurons. In addition, we found that exogenous TGFβ treatment of motor neurons for 24 hours decreases the soma count in both patients and controls, recapitulating the toxicity of TGFβ stimulation. Understanding how the ROCK pathway modulates motor neuron biology and TGFβ upregulation may provide insight into the mechanism of the disease.Support or Funding InformationNational Institute of Neurological Disorders and Stroke (NINDS) intramural funding.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Man-in-the-barrel syndrome as an atypical form of Amyotrophic Lateral Sclerosis

The “Man-in-the-barrel syndrome” makes reference to a picture of bilateral brachial muscular weakness, which incapacitates the patients in functional activities with upper limbs elevation. Since its description, there are several cases described of patients with this syndrome, whose etiology differs from the first one described. We read the article by Sasaki et al. “Atypical form of amyotrophic lateral sclerosis: a new term to define a previously well-known form of ALS” (2000), concerning the atypical form of amyotrophic lateral sclerosis (ALS). The pattern of muscular atrophy in these patients differed from that of typical ALS in that severe muscle involvement was confined to the upper limbs, predominantly the proximal portion and shoulder girdle.

Increased IP-10 production by blood–nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy

ObjectiveDysfunction of the blood–nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the...

Altered oligomeric states in pathogenic ALS2 variants associated with juvenile motor neuron diseases cause loss of ALS2-mediated endosomal function

Familial amyotrophic lateral sclerosis type 2 (ALS2) is a juvenile autosomal recessive motor neuron disease caused by the mutations in the ALS2 gene. The ALS2 gene product, ALS2/alsin, forms a homophilic oligomer and acts as a guanine nucleotide-exchange factor (GEF) for the small GTPase Rab5. This oligomerization is crucial for both Rab5 activation and ALS2-mediated endosome fusion and maturation in cells. Recently, we have shown that pathogenic missense ALS2 mutants retaining the Rab5 GEF activity fail to properly localize to endosomes via Rac1-stimulated macropinocytosis. However, the molecular mechanisms underlying dysregulated distribution of ALS2 variants remain poorly understood. Therefore, we sought to clarify the relationship between intracellular localization and oligomeric states of pathogenic ALS2 variants. Upon Rac family small GTPase 1 (Rac1) activation, all mutants tested moved from the cytosol to membrane ruffles but not to macropinosomes and/or endosomes. Furthermore, most WT ALS2 complexes were tetramers. Importantly, the sizes of an ALS2 complex carrying missense mutations in the N terminus of the regulator of chromosome condensation 1-like domain (RLD) or in-frame deletion in the pleckstrin homology domain were shifted toward higher molecular weight, whereas the C-terminal vacuolar protein sorting 9 (VPS9) domain missense mutant existed as a smaller dimeric or trimeric smaller form. Furthermore, in silico mutagenesis analyses using the RLD protein structure in conjunction with a cycloheximide chase assay in vitro disclosed that these missense mutations led to a decrease in protein stability. Collectively, disorganized higher structures of ALS2 variants might explain their impaired endosomal localization and the stability, leading to loss of the ALS2 function.

Tau Tubulin Kinase 1 (TTBK1), a new player in the fight against neurodegenerative diseases

Tau-tubuline kinases (TTBK) are a family of serine/threonine and tyrosine kinases recently discovered and implicated in the phosphorylation of important substrates such as tau, tubuline or TDP-43. Its two homologs, TTBK1 and TTBK2, show different expression patterns and different involvements in physiological mechanisms of great importance such as mitosis, ciliogenesis and neurotransmission. Their phosphorylation activity has also linked them to the development of neurodegenerative diseases like Alzheimer's disease, amyotrophic lateral sclerosis or spinocerebellar ataxia type 11. There are currently only three inhibitors of these kinases described in the literature. This review intends to give an overview of the structure, expression, physiological and pathological mechanisms of both kinases as well as an extended analysis on the molecules that can inhibit them. The final analysis of all this information led us to propose TTBK1 as a new target for the treatment of neurodegenerative diseases and its selective inhibitors as potential effective drugs for the treatment of these severe unmet disorders.

The reunification of amyotrophic lateral sclerosis

Historically characterised as a neuromuscular disease involving progressive loss of both central and peripheral motor neurons, amyotrophic lateral sclerosis (ALS) now sits among the cerebral neurodegenerative syndromes, involving clinical, pathological...

The heterozygous R155C VCP mutation: Toxic in humans! Harmless in mice?

Heterozygous missense mutations in the human VCP gene cause inclusion body myopathy associated with Paget disease of bone and fronto-temporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). The exact molecular mechanisms by which VCP mutations cause disease manifestation in different tissues are incompletely understood. In the present study, we report the comprehensive analysis of a newly generated R155C VCP knock-in mouse model, which expresses the ortholog of the second most frequently occurring human pathogenic VCP mutation. Heterozygous R155C VCP knock-in mice showed decreased plasma lactate, serum albumin and total protein concentrations, platelet numbers, and liver to body weight ratios, and increased oxygen consumption and CD8+/Ly6C + T-cell fractions, but none of the typical human IBMPFD or ALS pathologies. Breeding of heterozygous mice did not yield in the generation of homozygous R155C VCP knock-in animals. Immunoblotting showed identical total VCP protein levels in human IBMPFD and murine R155C VCP knock-in tissues as compared to wild-type controls. However, while in human IBMPFD skeletal muscle tissue 70% of the total VCP mRNA was derived from the mutant allele, in R155C VCP knock-in mice only 5% and 7% mutant mRNA were detected in skeletal muscle and brain tissue, respectively. The lack of any obvious IBMPFD or ALS pathology could thus be a consequence of the very low expression of mutant VCP. We conclude that the increased and decreased fractions of the R155C mutant VCP mRNA in man and mice, respectively, are due to missense mutation-induced, divergent alterations in the biological half-life of the human and murine mutant mRNAs. Furthermore, our work suggests that therapy approaches lowering the expression of the mutant VCP mRNA below a critical threshold may ameliorate the intrinsic disease pathology.

Amyotrophic lateral sclerosis: the complex path to precision medicine

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the corticomotorneuronal network responsible for voluntary movement. There are well-established clinical, genetic and pathological overlaps between ALS and frontotemporal dementia (FTD), which together constitute the ‘TDP-43 proteinopathies’. An ever-expanding list of genes in which mutation leads to typical ALS have implicated abnormalities in RNA processing, protein homoeostasis and axonal transport. How these apparently distinct pathways converge to cause the characteristic clinical syndrome of ALS remains unclear. Although there are major gaps in our understanding of the essential nature of ALS pathophysiology, the identification of genetic causes in up to 15% of ALS patients, coupled with advances in biotechnology and biomarker research provide a foundation for approaches to treatment based on ‘precision medicine’, and even prevention of the disease in pre-symptomatic mutation carriers in the future. Currently, multidisciplinary care remains the bedrock of management and this is increasingly being put onto an evidence-based footing.

Senataxin mutations elicit motor neuron degeneration phenotypes and yield TDP-43 mislocalization in ALS4 mice and human patients.

Amyotrophic lateral sclerosis type 4 (ALS4) is a rare, early-onset, autosomal dominant form of ALS, characterized by slow disease progression and sparing of respiratory musculature. Dominant, gain-of-function mutations in the senataxin gene (SETX) cause ALS4, but the mechanistic basis for motor neuron toxicity is unknown. SETX is a RNA-binding protein with a highly conserved helicase domain, but does not possess a low-complexity domain, making it unique among ALS-linked disease proteins. We derived ALS4 mouse models by expressing two different senataxin gene mutations (R2136H and L389S) via transgenesis and knock-in gene targeting. Both approaches yielded SETX mutant mice that develop neuromuscular phenotypes and motor neuron degeneration. Neuropathological characterization of SETX mice revealed nuclear clearing of TDP-43, accompanied by TDP-43 cytosolic mislocalization, consistent with the hallmark pathology observed in human ALS patients. Postmortem material from ALS4 patients exhibited TDP-43 mislocalization in spinal cord motor neurons, and motor neurons from SETX ALS4 mice displayed enhanced stress granule formation. Immunostaining analysis for nucleocytoplasmic transport proteins Ran and RanGAP1 uncovered nuclear membrane abnormalities in the motor neurons of SETX ALS4 mice, and nuclear import was delayed in SETX ALS4 cortical neurons, indicative of impaired nucleocytoplasmic trafficking. SETX ALS4 mice thus recapitulated ALS disease phenotypes in association with TDP-43 mislocalization and provided insight into the basis for TDP-43 histopathology, linking SETX dysfunction to common pathways of ALS motor neuron degeneration.

Association between Amyotrophic Lateral Sclerosis and Diabetes Mellitus Type I and II, a New York State Planning and Research Cooperation System Database Analysis (1998–2014) (P6.461)

Association between Amyotrophic Lateral Sclerosis and Diabetes Mellitus Type I and II, a New York State Planning and Research Cooperation System Database Analysis (1998–2014) (P6.461)

Temperature effects on accommodative processes in simulated amyotrophic lateral sclerosis in the physiological range

The present study investigates the temperature dependence of electrotonic potentials in mathematically-simulated myelinated axons with one of three increasingly-severe type of amyotrophic lateral sclerosis (ALS) pathology, termed as ALS1, ALS2 and ALS3, respectively, in the physiological range (30-37∘C). These potentials were elicited by long-lasting (100 ms) subthreshold polarizing current stimuli (±40% of the threshold). Numerical solutions were computed using our temperature-dependent multi-layered model. The results showed the following trends: (i) in ALS1, polarizing electrotonic potentials were normal; (ii) in ALS2 and ALS3, action potentials were elicited in the early parts of the depolarizing electrotonic potentials, and (iii) in ALS3, spontaneous discharges were elicited after the termination of applied hyperpolarizing stimuli (i.e., post-anodal excitation). The ionic currents underlying electrotonic potentials in the ALS1 case were attributable to the activation of potassium fast (Kf+) and slow (Ks+) channels in the nodal and internodal axolemma beneath the myelin sheath. By contrast, in ALS2 and ALS3, the depolarizing stimuli activated the classical "transient" Na+ channels in the nodal and internodal axolemma beneath the myelin sheath eliciting action potential generation. These results obtained were closer to those observed in hypothermia (⩽25∘C) than in hyperthermia (⩾40∘C).

Swallowing impairments in Amyotrophic Lateral Sclerosis and Myotonic Dystrophy type 1: Looking for the portrait of dysphagic patient in neuromuscular diseases.

Dysphagia is a critical symptom of Neuromuscular Diseases and is often associated with considerable morbidity and mortality. This study is designed to investigate the prevalence of dysphagia and to identify different clinical profiles of swallowing disorders in Myotonic Dystrophy type 1 (DM1) and Amyotrophic Lateral Sclerosis (ALS), the most common Neuromuscular Diseases in the adult age. Consecutive DM1 and ALS patients from 2013 to 2015 referred to a Centre for Neuromuscular Disease were enrolled. A comprehensive assessment of swallowing function with a Clinical Swallowing Examination and Fluid and Food Trials was performed. 157 patients were included: 86 ALS, 71 DM1. The dysphagic patients affected by ALS and DM1 (79% and 86% of the respective samples) showed two different profiles. ALS patients with dysphagia were older and underweight. They experienced a global dysfunction of the oral and pharyngeal phases with more difficulty in swallowing thin liquids. Conversely, DM1 patients with dysphagia were younger and tended to obesity. Most of them showed impairment of oral phase and had more frequently difficulty in swallowing solid bolus. The recognition of specific clinical profiles supports and guides the detection of swallowing disorders in patients with neuromuscular diseases.

Speech deterioration in amyotrophic lateral sclerosis (ALS) after manifestation of bulbar symptoms.

The symptoms and their progression in amyotrophic lateral sclerosis (ALS) are typically studied after the diagnosis has been confirmed. However, many people with ALS already have severe dysarthria and loss of adequate speech at the time of diagnosis. Speech-and-language therapy interventions should be targeted timely based on communicative need in ALS. To investigate how long natural speech will remain functional and to identify the changes in the speech of persons with ALS. Altogether 30 consecutive participants were studied and divided into two groups based on the initial type of ALS, bulbar or spinal. Their speech disorder was evaluated on severity, articulation rate and intelligibility during the 2-year follow-up. The ability to speak deteriorated to poor and necessitated augmentative and alternative communication (AAC) methods with 60% of the participants. Their speech remained adequate on average for 18 months from the first bulbar symptom. Severity, articulation rate and intelligibility declined with nearly all participants during the study. To begin with speech deteriorated more in the bulbar group than in the spinal group and the difference remained during the whole follow-up with some exceptions. The onset of bulbar symptoms indicated the time to loss of speech better than when assessed from ALS diagnosis or the first speech therapy evaluation. In clinical work, it is important to take the initial type of ALS into consideration when determining the urgency of AAC measures as people with bulbar-onset ALS are more susceptible to delayed evaluation and AAC intervention.

FUS Mutant Human Motoneurons Display Altered Transcriptome and microRNA Pathways with Implications for ALS Pathogenesis.

SummaryThe FUS gene has been linked to amyotrophic lateral sclerosis (ALS). FUS is a ubiquitous RNA-binding protein, and the mechanisms leading to selective motoneuron loss downstream of ALS-linked mutations are largely unknown. We report the transcriptome analysis of human purified motoneurons, obtained from FUS wild-type or mutant isogenic induced pluripotent stem cells (iPSCs). Gene ontology analysis of differentially expressed genes identified significant enrichment of pathways previously associated to sporadic ALS and other neurological diseases. Several microRNAs (miRNAs) were also deregulated in FUS mutant motoneurons, including miR-375, involved in motoneuron survival. We report that relevant targets of miR-375, including the neural RNA-binding protein ELAVL4 and apoptotic factors, are aberrantly increased in FUS mutant motoneurons. Characterization of transcriptome changes in the cell type primarily affected by the disease contributes to the definition of the pathogenic mechanisms of FUS-linked ALS.

S70 Estimating motor unit number from CMAP scans – MScanFIT MUNE

Objectives There is no method that can measure the exact number of motor units, therefore motor unit number estimation (MUNE) methods have been developed. Most MUNE methods are based on estimating the size of an average surface-recorded motor unit potential and dividing that value into maximal compound action potential (CMAP). This makes the estimates strongly influenced by any bias in unit selection. Other limitations of the existing MUNE methods are the presence of subjectivity in the estimation process, the failure to sample enough units or the long time to perform the test or analyse. To overcome these limitations, a new MUNE method was recently developed, so-called ‘MScanFit MUNE‘, (MScan). Methods MScan meets the above-mentioned criticisms by fitting a model to a detailed stimulus-response curve (∼500 stimuli) or ‘CMAP scan’, taking into account the threshold variability of all the units, and avoiding subjectivity. Results The method has been found to be accurate (mean absolute error 7%) for simulated data.The reproducibility and the diagnostic utility of MScan were found to be good in healthy controls and in patients with amyotrophic lateral sclerosis (ALS) and different types of polyneuropathy. Discussion MScan revealed in neurofibromatosis-type-2 patients denervation and reinnervation in peripheral nerves suggesting that it may be used to quantify and monitor disease progression. Conclusions MScan is a novel method with good reproducibility, and may be performed in less than five minutes. Significance Preliminary results suggest MScan as a promising MUNE method with potential to be used in diagnoses and monitoring disease progression, particularly in ALS.

Lack of association between the P413L variant of chromogranin B and ALS risk or age at onset: a meta-analysis

Background: Amyotrophic lateral sclerosis (ALS), the most common motor neuron disease, is thought to result from interaction of genetic and environmental risk factors. Whether the potentially functional exonic P413L variant in the chromogranin B gene influences ALS risk and age at onset is controversial. Method: We meta-analysed or other studies assessing the association between the P413L variant and ALS risk or age at ALS onset indexed in Web of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases. Results: Five case-control studies were analysed, involving 2639 patients with sporadic ALS, 201 with familial ALS and 3381 controls. No association was detected between risk of either ALS type and the CT + TT genotype or T-allele of the P413L variant. Age at ALS onset was similar between carriers and non-carriers of the T-allele. Conclusion: The available evidence suggests that the P413L variant of chromogranin B is not associated with ALS risk or age at ALS onset. These results should be validated in large, well-designed studies.

Whole exome sequencing and DNA methylation analysis in a clinical amyotrophic lateral sclerosis cohort.

BackgroundGene discovery has provided remarkable biological insights into amyotrophic lateral sclerosis (ALS). One challenge for clinical application of genetic testing is critical evaluation of the significance of reported variants.MethodsWe use whole exome sequencing (WES) to develop a clinically relevant approach to identify a subset of ALS patients harboring likely pathogenic mutations. In parallel, we assess if DNA methylation can be used to screen for pathogenicity of novel variants since a methylation signature has been shown to associate with the pathogenic C9orf72 expansion, but has not been explored for other ALS mutations. Australian patients identified with ALS‐relevant variants were cross‐checked with population databases and case reports to critically assess whether they were “likely causal,” “uncertain significance,” or “unlikely causal.”ResultsPublished ALS variants were identified in >10% of patients; however, in only 3% of patients (4/120) could these be confidently considered pathogenic (in SOD1 and TARDBP). We found no evidence for a differential DNA methylation signature in these mutation carriers.ConclusionsThe use of WES in a typical ALS clinic demonstrates a critical approach to variant assessment with the capability to combine cohorts to enhance the largely unknown genetic basis of ALS.

Diagnostic and Prognostic Biomarkers in Amyotrophic Lateral Sclerosis

A clearer definition of the role of neurofilament light chain (NFL) as a biomarker in amyotrophic lateral sclerosis (ALS) is needed. To assess the ability of NFL to serve as a diagnostic biomarker in ALS and the prognostic value of cerebrospinal fluid NFL in patients with ALS. In this single-center, retrospective, longitudinal study, disease progression was assessed by the ALS Functional Rating Score-Revised and the ALS Milano-Torino Staging system at baseline and 6, 12, 24, and 36 months. Cerebrospinal fluid samples were obtained from 176 patients admitted to the Department of Neurosciences of the University of Padua, Padova, Italy, from January 1, 2010, through February 29, 2016. Patients with ALS underwent ambulatory follow-up at the same department. Levels of NFL. The study included 94 patients with ALS (64 men [36.4%] and 30 women [17.0%]; median age, 62.5 years), 20 patients with frontotemporal dementia (FTD) (8 men [4.5%] and 12 women [6.8%]; median age, 65 years), 18 patients with motor neuropathies (14 men [8.0%] and 4 women [2.3%]; median age, 63 years), and 44 controls (24 men [13.6%] and 20 women [11.4%]; median age, 54 years). Log-transformed NFL (log[NFL]) concentrations were higher in the ALS and FTD groups compared with the motor neuropathies and control groups (hazard ratio [HR], 2.45; 95% CI, 1.66-3.61; P < .001). Patients with typical ALS (HR, 1.0 [reference]), progressive bulbar palsy (HR, 1.48; 95% CI, 0.58-3.75; P = .41), and upper motor neuron dominant ALS (HR, 0.12; 95% CI, 0.02-0.61; P = .01) had higher levels of NFL than did those with flail arm or leg syndrome (HR, 0.28; 95% CI, 0.08-0.10; P = .049) and progressive muscular atrophy (HR, 0.17; 95% CI, 0.22-1.36; P = .10). There was an inverse correlation between log[NFL] concentration and overall survival (HR, 2.45; 95% CI, 1.66-3.61; P < .001). There was no evidence of different log[NFL] concentrations and survival in genetic ALS. This study confirms the role of NFL as a biomarker in ALS. Elevation in NFL levels in patients with upper motor neuron involvement and FTD might reflect the corticospinal tract degeneration. Low NFL levels in patients with lower motor neuron signs might be a prognostic indicator of milder phenotypes of disease.