Presymptomatic Amyotrophic Lateral Sclerosis Research Articles

Possible changes in motor neuron discharge characteristics in presymptomatic amyotrophic lateral sclerosis.

Possible changes in motor neuron discharge characteristics in presymptomatic amyotrophic lateral sclerosis.

The Miami Framework for ALS and related neurodegenerative disorders: an integrated view of phenotype and biology.

Increasing appreciation of the phenotypic and biological overlap between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, alongside evolving biomarker evidence for a pre-symptomatic stage of disease and observations that this stage of disease might not always be clinically silent, is challenging traditional views of these disorders. These advances have highlighted the need to adapt ingrained notions of these clinical syndromes to include both the full phenotypic continuum - from clinically silent, to prodromal, to clinically manifest - and the expanded phenotypic spectrum that includes ALS, frontotemporal dementia and some movement disorders. The updated clinical paradigms should also align with our understanding of the biology of these disorders, reflected in measurable biomarkers. The Miami Framework, emerging from discussions at the Second International Pre-Symptomatic ALS Workshop in Miami (February 2023; a full list of attendees and their affiliations appears in the Supplementary Information) proposes a classification system built on: first, three parallel phenotypic axes - motor neuron, frontotemporal and extrapyramidal - rather than the unitary approach of combining all phenotypic elements into a single clinical entity; and second, biomarkers that reflect different aspects of the underlying pathology and biology of neurodegeneration. This framework decouples clinical syndromes from biomarker evidence of disease and builds on experiences from other neurodegenerative diseases to offer a unified approach to specifying the pleiotropic clinical manifestations of disease and describing the trajectory of emergent biomarkers.

Selective removal of misfolded SOD1 delays disease onset in a mouse model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. There is no cure currently. The discovery that mutations in the gene SOD1 are a cause of ALS marks a breakthrough in the search for effective treatments for ALS. SOD1 is an antioxidant that is highly expressed in motor neurons. Human SOD1 is prone to aberrant modifications. Familial ALS-linked SOD1 variants are particularly susceptible to aberrant modifications. Once modified, SOD1 undergoes conformational changes and becomes misfolded. This study aims to determine the effect of selective removal of misfolded SOD1 on the pathogenesis of ALS. Based on the chaperone-mediated protein degradation pathway, we designed a fusion peptide named CT4 and tested its efficiency in knocking down intracellularly misfolded SOD1 and its efficacy in modifying the pathogenesis of ALS. Expression of the plasmid carrying the CT4 sequence in human HEK cells resulted in robust removal of misfolded SOD1 induced by serum deprivation. Co-transfection of the CT4 and the G93A-hSOD1 plasmids at various ratios demonstrated a dose-dependent knockdown efficiency on G93A-hSOD1, which could be further increased when misfolding of SOD1 was enhanced by serum deprivation. Application of the full-length CT4 peptide to primary cultures of neurons expressing the G93A variant of human SOD1 revealed a time course of the degradation of misfolded SOD1; misfolded SOD1 started to decrease by 2 h after the application of CT4 and disappeared by 7 h. Intravenous administration of the CT4 peptide at 10mg/kg to the G93A-hSOD1 reduced human SOD1 in spinal cord tissue by 68% in 24 h and 54% in 48 h in presymptomatic ALS mice. Intraperitoneal administration of the CT4 peptide starting from 60days of age significantly delayed the onset of ALS and prolonged the lifespan of the G93A-hSOD1 mice. The CT4 peptide directs the degradation of misfolded SOD1 in high efficiency and specificity. Selective removal of misfolded SOD1 significantly delays the onset of ALS, demonstrating that misfolded SOD1 is the toxic form of SOD1 that causes motor neuron death. The study proves that selective removal of misfolded SOD1 is a promising treatment for ALS.

Primary care blood tests show lipid profile changes in pre-symptomatic amyotrophic lateral sclerosis.

Multiple sources of evidence suggest that changes in metabolism may precede the onset of motor symptoms in amyotrophic lateral sclerosis. This study aimed to seek evidence for alterations in the levels of blood indices collected routinely in the primary care setting prior to the onset of motor symptoms in amyotrophic lateral sclerosis. Premorbid data, measured as part of routine health screening, for total cholesterol, high-density and low-density lipoprotein cholesterol, triglyceride, glycated haemoglobin A1c and creatinine were collected retrospectively from (i) a cohort of amyotrophic lateral sclerosis patients attending a specialist clinic (n = 143) and (ii) from primary care-linked data within UK Biobank. Data were fitted using linear mixed effects models with linear b-splines to identify inflection points, controlling for age and sex. In specialist amyotrophic lateral sclerosis clinic cases, models indicated decreasing levels of total and low-density lipoprotein cholesterol prior to an inflection point in the years before symptom onset (total cholesterol 3.25 years, low-density lipoprotein cholesterol 1.25 years), after which they stabilized or rose. A similar pattern was observed in amyotrophic lateral sclerosis cases within UK Biobank, occurring several years prior to diagnosis (total cholesterol 7 years, low-density lipoprotein cholesterol 7.25 years), differing significantly from matched controls. High-density lipoprotein cholesterol followed a similar pattern but was less robust to sensitivity analyses. Levels of triglyceride remained stable throughout. Glycated haemoglobin temporal profiles were not consistent between the clinic and biobank cohorts. Creatinine level trajectories prior to amyotrophic lateral sclerosis did not differ significantly from controls but decreased significantly in the symptomatic period after an inflection point of 0.25 years after symptom onset (clinic cohort) or 0.5 years before diagnosis (UK Biobank). These data provide further evidence for a pre-symptomatic period of dynamic metabolic change in amyotrophic lateral sclerosis, consistently associated with alterations in blood cholesterols. Such changes may ultimately contribute to biomarkers applicable to population screening and for pathways guiding the targeting of preventative therapy.

Metabolic alterations precede neurofilament changes inpresymptomatic ALS gene carriers.

The emergence of potentially effective new therapies for genetic forms of amyotrophic lateral sclerosis (ALS) necessitates the identification of biomarkers to facilitate early treatment, prior to the onset of motor symptoms. Here, we sought to investigate whether metabolic alterations are detectable in presymptomatic ALS gene mutation carriers, and whether such alterations precede neurofilament light chain (NfL) changes in serum. Between 02/2014 and 11/2021, we prospectively studied 60 presymptomatic ALS gene mutation carriers (40% male, age 48.7±14.9; 28 C9orf72, 22 SOD1, 10 other) compared to 73 individuals from the same families (47%male, age 47.4±12.9) without pathogenic mutations as controls. Bioimpedance analysis (BIA) and indirect calorimetry were performed, and Body Mass Index (BMI), Fat Mass (FM), Body Fat Percentage, Body Water (BW), Lean Body Mass (LBM), Extracellular Mass (ECM), Body Cell Mass (BCM), ECM/BCM ratio, Cells Percentage, Phase Angle, Resting Metabolic Rate (RMR), Metabolic Ratio (MR), and NfL were measured. Participants and evaluators were blinded regarding gene carrier status. Presymptomatic ALS gene carriers showed reduced LBM (p=0.02), BCM (p=0.004), Cells Percentage (p=0.04), BW (p=0.02), Phase Angle (p=0.04), and increased ECM/BCM ratio (p=0.04), consistently indicating a loss of metabolically active body cells. While in C9orf72 mutation carriers all tissue masses were reduced, only metabolically active tissue was affected in SOD1 mutation carriers. Unexpectedly, RMR (p=0.009) and MR (p=0.01) were lower in presymptomatic ALS gene carriers compared to non-carriers. NfL serum levels were similar in mutation carriers and non-carriers (p=0.60). The observed metabolic phenomena might reflect reduced physical activity and/or preemptive, insufficient compensatory mechanisms to prepare for the later hypermetabolic state. As pre-symptomatic biomarkers we propose ECM/BCM ratio and Phase Angle for SOD1, and a 4-compartment affection in BIA for C9orf72 mutation carriers. This work was an investigator-initiated trial. On the German side, there was no institutional or industrial funding. On the Swedish side, this work was supported by grants from the Swedish Brain Foundation (grants nr. 2013-0279, 2016-0303, 2018-0310, 2020-0353), the Swedish Research Council (grants nr. 2012-3167, 2017-03100), the Knut and Alice Wallenberg Foundation (grants nr. 2012.0091, 2014.0305, 2020.0232), the Ulla-Carin Lindquist Foundation, Umeå University (223-2808-12, 223-1881-13, 2.1.12-1605-14) and the Västerbotten County Council (grants nr 56103-7002829), King Gustaf V:s and Queen Victoria's Freemason's Foundation.

Mutation-specific metabolic profiles in presymptomatic amyotrophic lateral sclerosis.

Growing evidence shows that ALS patients feature a disturbed energy metabolism. However, these features have rarely been investigated in the presymptomatic stage. A total of 60 presymptomatic ALS mutation carriers and 70 age- and gender-matched controls (non-mutation carriers from the same families) were recruited. All subjects underwent assessments of their metabolic profiles under fasting conditions at enrollment, including body mass index (BMI), blood pressure and serum levels of blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein. All mutations combined, no differences between presymptomatic ALS gene carriers and controls were found. From a cardiovascular point of view, presymptomatic chromosome 9 open reading frame 72 (C9ORF72) gene carriers showed lower cardiovascular risk profiles compared to healthy controls, including lower BMI (median 22.9, interquartile range [IQR] 20.6-26.1 kg/m2 vs. 24.9, IQR 22.7-30.5 kg/m2 ; p=0.007), lower systolic blood pressure (120, IQR 110-130 mmHg vs. 128, IQR 120-140 mmHg; p=0.02), lower fasting serum glucose (89.0, IQR 85.0-97.0 mg/dl vs. 96.0, IQR 89.3-102.0 mg/dl; p=0.005) and higher HDL (1.6, IQR 1.3-1.8 mmol/l vs. 1.2, IQR 1.0-1.4 mmol/l; p=0.04). However, presymptomatic superoxide dismutase 1 (SOD1) gene mutation carriers showed higher cardiovascular risk profiles compared to healthy controls, including higher BMI (28.0,IQR 26.1-31.5 kg/m2 vs. 24.9, IQR 22.7-30.5 kg/m2 ; p=0.02), higher fasting serum glucose (100.0, IQR 94.0-117.0 mg/dl vs. 96.0, IQR 89.3-102.0 mg/dl; p=0.04) and lower HDL (1.2, IQR 1.0-1.4 mmol/l vs. 1.4, IQR 1.2-1.7 mmol/l; p=0.01). These features were most prominent in patients carrying SOD1 gene mutations associated with slow disease progression. This study identified distinct metabolic profiles in presymptomatic ALS gene carriers, which might be associated with disease progression in the symptomatic phase.

Differential Effects of Invasive Anodal Trans-spinal Direct Current Stimulation on Monosynaptic Excitatory Postsynaptic Potentials, Ia Afferents Excitability, and Motoneuron Intrinsic Properties Between Superoxide Dismutase Type-1 Glycine to Alanine Substitution at Position 93 and Wildtype Mice

In presymptomatic amyotrophic lateral sclerosis (ALS), spinal motoneurons (MNs) have reduced firing patterns and synaptic excitation levels. Preliminary data indicated that in the SOD1 G93A mouse model of ALS, monosynaptic excitatory postsynaptic potentials (EPSPs) evoked in spinal MN by Ia proprioceptive afferent stimulation could be facilitated by trans-spinal direct current stimulation (tsDCS). However, which element of the Ia afferent-MN circuit is affected by tsDCS, and whether tsDCS-induced EPSP facilitation is a general phenomenon or specific to the superoxide dismutase type-1 (SOD1) Glycine to Alanine substitution at position 93 (G93A) mutation, remain to be determined. In this study, we have applied 15-minute tsDCS to the lumbar segments of presymptomatic SOD1 and wildtype (WT) mice and explored its impact on MN passive membrane properties, EPSP amplitude, and Ia afferent activity. While anodal tsDCS induced short-lasting EPSP facilitation in both SOD1 and WT mice, Ia afferent activity and passive membrane properties were altered only in SOD1 mice. Interestingly, EPSP amplitudes of SOD1 mice remained facilitated for at least 1 h after current application, but no long-lasting effect was observed in WT mice. Moreover, anodal tsDCS failed to induce any long-lasting changes in MN passive membrane properties in both SOD1 and WT mice. Conversely, cathodal tsDCS decreased Ia afferent induced EPSP amplitudes only during current application in SOD1 MNs, and no significant effects on Ia afferents excitability were observed. Our findings indicate the high susceptibility of SOD1 MNs to tsDCS and highlight the potential of this neuromodulation technique for the treatment of ALS.

Design of a Randomized, Placebo-Controlled, Phase 3 Trial of Tofersen Initiated in Clinically Presymptomatic SOD1 Variant Carriers: the ATLAS Study

Despite extensive research, amyotrophic lateral sclerosis (ALS) remains a progressive and invariably fatal neurodegenerative disease. Limited knowledge of the underlying causes of ALS has made it difficult to target upstream biological mechanisms of disease, and therapeutic interventions are usually administered relatively late in the course of disease. Genetic forms of ALS offer a unique opportunity for therapeutic development, as genetic associations may reveal potential insights into disease etiology. Genetic ALS may also be amenable to investigating earlier intervention given the possibility of identifying clinically presymptomatic, at-risk individuals with causative genetic variants. There is increasing evidence for a presymptomatic phase of ALS, with biomarker data from the Pre-Symptomatic Familial ALS (Pre-fALS) study showing that an elevation in blood neurofilament light chain (NfL) precedes phenoconversion to clinically manifest disease. Tofersen is an investigational antisense oligonucleotide designed to reduce synthesis of superoxide dismutase 1 (SOD1) protein through degradation of SOD1 mRNA. Informed by Pre-fALS and the tofersen clinical development program, the ATLAS study (NCT04856982) is designed to evaluate the impact of initiating tofersen in presymptomatic carriers of SOD1 variants associated with high or complete penetrance and rapid disease progression who also have biomarker evidence of disease activity (elevated plasma NfL). The ATLAS study will investigate whether tofersen can delay the emergence of clinically manifest ALS. To our knowledge, ATLAS is the first interventional trial in presymptomatic ALS and has the potential to yield important insights into the design and conduct of presymptomatic trials, identification, and monitoring of at-risk individuals, and future treatment paradigms in ALS.

Methylome analysis of ALS patients and presymptomatic mutation carriers in blood cells

Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron disease with a monogenic cause in approximately 10% of cases. However, familial clustering of disease without inheritance in a Mendelian manner and the broad range of phenotypes suggest the presence of epigenetic mechanisms. Hence, we performed an epigenome-wide association study on sporadic, symptomatic and presymptomatic familial ALS cases with mutations in C9ORF72 and FUS and healthy controls studying DNA methylation in blood cells. We found differentially methylated DNA positions (DMPs) and regions embedding DMPs associated with either disease status, C9ORF72 or FUS mutation status. One DMP reached methylome-wide significance and is attributed to a region encoding a long non-coding RNA (LOC389247). Furthermore, we could demonstrate co-localization of DMPs with an ALS-associated GWAS region near the SCN7A/SCN9A and XIRP2 genes. Finally, a classifier model that predicts disease status (ALS, healthy) classified all but one presymptomatic mutation carrier as healthy, suggesting that the presence of ALS symptoms rather than the presence of ALS-associated genetic mutations is associated with blood cell DNA methylation.

Bone Marrow Stromal Cell Antigen 2: Is a Potential Neuroinflammation Biomarker of SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis in Pre-symptomatic Stage.

Neuroinflammation has long been thought to be associated with amyotrophic lateral sclerosis (ALS) development and progression. However, the exact molecular mechanisms of neuroinflammation underlying ALS remain largely unknown. In the present study, we attempted to elucidate the genetic basis of neuroinflammation in ALS by comparing the transcriptomic profile of the anterior horns of the lumbar spinal cord (AHLSC) between SOD1G93A mice and their wild-type (WT) littermates. Our results revealed that immune-related genes were selectively up-regulated in the AHLSC of pre-symptomatic ALS mice (40 days of age) compared to age-matched WT control mice. Notably, the differential expression level of these immune-related genes became more significant at the symptomatic stage of disease (90 days of age) in the ALS mice. Subsequently, eight genes involved in innate immune response in the AHLSC of ALS mice were further validated by qRT-PCR analysis. Of these genes, bone marrow stromal cell antigen 2 (BST2) was found for the first time to be significantly higher in the AHLSC of pre-symptomatic ALS mice when compared with WT mice. The increasing trend of BST2 expression became more obvious in the symptomatic stage. Immunofluorescent staining further confirmed that BST2 is mainly expressed on microglia in the AHLSC of ALS mice. These findings support the view that immune-related neuroinflammation is involved in the early pathogenesis of ALS, and BST2 may serve as a potential target for ameliorating microglia-mediated neuroinflammation pathologies in ALS.

Swim Training Ameliorates Hyperlocomotion of ALS Mice and Increases Glutathione Peroxidase Activity in the Spinal Cord.

(1) Background: Amyotrophic lateral sclerosis (ALS) is an incurable, neurodegenerative disease. In some cases, ALS causes behavioral disturbances and cognitive dysfunction. Swimming has revealed a neuroprotective influence on the motor neurons in ALS. (2) Methods: In the present study, a SOD1-G93A mice model of ALS were used, with wild-type B6SJL mice as controls. ALS mice were analyzed before ALS onset (10th week of life), at ALS 1 onset (first symptoms of the disease, ALS 1 onset, and ALS 1 onset SWIM), and at terminal ALS (last stage of the disease, ALS TER, and ALS TER SWIM), and compared with wild-type mice. Swim training was applied 5 times per week for 30 min. All mice underwent behavioral tests. The spinal cord was analyzed for the enzyme activities and oxidative stress markers. (3) Results: Pre-symptomatic ALS mice showed increased locomotor activity versus control mice; the swim training reduced these symptoms. The metabolic changes in the spinal cord were present at the pre-symptomatic stage of the disease with a shift towards glycolytic processes at the terminal stage of ALS. Swim training caused an adaptation, resulting in higher glutathione peroxidase (GPx) and protection against oxidative stress. (4) Conclusion: Therapeutic aquatic activity might slow down the progression of ALS.

Preventing amyotrophic lateral sclerosis: insights from pre-symptomatic neurodegenerative diseases.

Significant progress has been made in understanding the pre-symptomatic phase of amyotrophic lateral sclerosis. While much is still unknown, advances in other neurodegenerative diseases offer valuable insights. Indeed, it is increasingly clear that the well-recognized clinical syndromes of Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, spinal muscular atrophy and frontotemporal dementia are also each preceded by a pre-symptomatic or prodromal period of varying duration, during which the underlying disease process unfolds, with associated compensatory changes and loss of inherent system redundancy. Key insights from these diseases highlight opportunities for discovery in amyotrophic lateral sclerosis. The development of biomarkers reflecting amyloid and tau has led to a shift in defining Alzheimer’s disease based on inferred underlying histopathology. Parkinson’s disease is unique among neurodegenerative diseases in the number and diversity of non-genetic biomarkers of pre-symptomatic disease, most notably REM sleep behaviour disorder. Huntington’s disease benefits from an ability to predict the likely timing of clinically manifest disease based on age and CAG-repeat length alongside reliable neuroimaging markers of atrophy. Spinal muscular atrophy clinical trials have highlighted the transformational value of early therapeutic intervention, and studies in frontotemporal dementia illustrate the differential role of biomarkers based on genotype. Similar advances in amyotrophic lateral sclerosis would transform our understanding of key events in pathogenesis, thereby dramatically accelerating progress towards disease prevention. Deciphering the biology of pre-symptomatic amyotrophic lateral sclerosis relies on a clear conceptual framework for defining the earliest stages of disease. Clinically manifest amyotrophic lateral sclerosis may emerge abruptly, especially among those who harbour genetic mutations associated with rapidly progressive amyotrophic lateral sclerosis. However, the disease may also evolve more gradually, revealing a prodromal period of mild motor impairment preceding phenoconversion to clinically manifest disease. Similarly, cognitive and behavioural impairment, when present, may emerge gradually, evolving through a prodromal period of mild cognitive impairment or mild behavioural impairment before progression to amyotrophic lateral sclerosis. Biomarkers are critically important to studying pre-symptomatic amyotrophic lateral sclerosis and essential to efforts to intervene therapeutically before clinically manifest disease emerges. The use of non-genetic biomarkers, however, presents challenges related to counselling, informed consent, communication of results and limited protections afforded by existing legislation. Experiences from pre-symptomatic genetic testing and counselling, and the legal protections against discrimination based on genetic data, may serve as a guide. Building on what we have learned—more broadly from other pre-symptomatic neurodegenerative diseases and specifically from amyotrophic lateral sclerosis gene mutation carriers—we present a road map to early intervention, and perhaps even disease prevention, for all forms of amyotrophic lateral sclerosis.

ActRIIB:ALK4-Fc alleviates muscle dysfunction and comorbidities in murine models of neuromuscular disorders.

Patients with neuromuscular disorders suffer from a lack of treatment options for skeletal muscle weakness and disease comorbidities. Here, we introduce as a potential therapeutic agent a heterodimeric ligand-trapping fusion protein, ActRIIB:ALK4-Fc, which comprises extracellular domains of activin-like kinase 4 (ALK4) and activin receptor type IIB (ActRIIB), a naturally occurring pair of type I and II receptors belonging to the TGF-β superfamily. By surface plasmon resonance (SPR), ActRIIB:ALK4-Fc exhibited a ligand binding profile distinctly different from that of its homodimeric variant ActRIIB-Fc, sequestering ActRIIB ligands known to inhibit muscle growth but not trapping the vascular regulatory ligand bone morphogenetic protein 9 (BMP9). ActRIIB:ALK4-Fc and ActRIIB-Fc administered to mice exerted differential effects - concordant with SPR results - on vessel outgrowth in a retinal explant assay. ActRIIB:ALK4-Fc induced a systemic increase in muscle mass and function in wild-type mice and in murine models of Duchenne muscular dystrophy (DMD), amyotrophic lateral sclerosis (ALS), and disuse atrophy. Importantly, ActRIIB:ALK4-Fc improved neuromuscular junction abnormalities in murine models of DMD and presymptomatic ALS and alleviated acute muscle fibrosis in a DMD model. Furthermore, in combination therapy ActRIIB:ALK4-Fc increased the efficacy of antisense oligonucleotide M12-PMO on dystrophin expression and skeletal muscle endurance in an aged DMD model. ActRIIB:ALK4-Fc shows promise as a therapeutic agent, alone or in combination with dystrophin rescue therapy, to alleviate muscle weakness and comorbidities of neuromuscular disorders.

Is there hope that transpinal direct current stimulation corrects motoneuron excitability and provides neuroprotection in amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of largely unknown pathophysiology, characterized by the progressive loss of motoneurons (MNs). We review data showing that in presymptomatic ALS mice, MNs display reduced intrinsic excitability and impaired level of excitatory inputs. The loss of repetitive firing specifically affects the large MNs innervating fast contracting muscle fibers, which are the most vulnerable MNs in ALS. Interventions that aimed at restoring either the intrinsic excitability or the synaptic excitation result in a decrease of disease markers in MNs and delayed neuromuscular junction denervation. We then focus on trans‐spinal direct current stimulation (tsDCS), a noninvasive tool, since it modulates the activity of spinal neurons and networks. Effects of tsDCS depend on the polarity of applied current. Recent work shows that anodal tsDCS induces long‐lasting enhancement of MN excitability and synaptic excitation of spinal MNs. Moreover, we show preliminary results indicating that anodal tsDCS enhances the excitatory synaptic inputs to MNs in ALS mice. In conclusion, we suggest that chronic application of anodal tsDCS might be useful as a complementary method in the management of ALS patients.

FV 29 Executive eye movement impairment in presymptomatic amyotrophic lateral sclerosis mutation carriers

FV 29 Executive eye movement impairment in presymptomatic amyotrophic lateral sclerosis mutation carriers

Prediagnostic plasma metabolomics and the risk of amyotrophic lateral sclerosis.

To identify prediagnostic plasma metabolomic biomarkers associated with amyotrophic lateral sclerosis (ALS). We conducted a global metabolomic study using a nested case-control study design within 5 prospective cohorts and identified 275 individuals who developed ALS during follow-up. We profiled plasma metabolites using liquid chromatography-mass spectrometry and identified 404 known metabolites. We used conditional logistic regression to evaluate the associations between metabolites and ALS risk. Further, we used machine learning analyses to determine whether the prediagnostic metabolomic profile could discriminate ALS cases from controls. A total of 31 out of 404 identified metabolites were associated with ALS risk (p < 0.05). We observed inverse associations (n = 27) with plasma levels of diacylglycerides and triacylglycerides, urate, purine nucleosides, and some organic acids and derivatives, while we found positive associations for a cholesteryl ester, 2 phosphatidylcholines, and a sphingomyelin. The number of significant associations increased to 67 (63 inverse) in analyses restricted to cases with blood samples collected within 5 years of onset. None of these associations remained significant after multiple comparison adjustment. Further, we were not able to reliably distinguish individuals who became cases from controls based on their metabolomic profile using partial least squares discriminant analysis, elastic net regression, random forest, support vector machine, or weighted correlation network analyses. Although the metabolomic profile in blood samples collected years before ALS diagnosis did not reliably separate presymptomatic ALS cases from controls, our results suggest that ALS is preceded by a broad, but poorly defined, metabolic dysregulation years before the disease onset.

Neurofilament light: A candidate biomarker of presymptomatic amyotrophic lateral sclerosis and phenoconversion.

To evaluate neurofilament light (NfL) as a biomarker of the presymptomatic phase of amyotrophic lateral sclerosis (ALS). The study population includes 84 individuals at risk for developing ALS, 34 controls, 17 ALS patients, and 10 phenoconverters (at-risk individuals observed both before and after the emergence of clinically manifest disease). At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of individuals who are carriers of any ALS-associated gene mutation (in SOD1, C9orf72, TARDBP, FUS, VCP, etc), but who, at the time of enrollment, demonstrated no clinical symptoms or signs (including electromyographic evidence) of manifest disease. NfL in serum and cerebrospinal fluid (CSF) were quantified using an electrochemiluminescence immunoassay. Serum and CSF NfL are substantially higher in ALS patients compared to controls and at-risk individuals and remain relatively stable over time. Among phenoconverters, however, NfL levels were elevated (ie, above the range observed in controls) as far back as ∼12 months preceding the emergence of the earliest clinical symptoms or signs of disease. Serum (and CSF) NfL are informative biomarkers of presymptomatic ALS, providing a new tool to quantify presymptomatic disease progression and to potentially predict the timing of clinical phenoconversion. As such, quantification of NfL may aid the design and implementation of early therapeutic intervention for affected individuals and/or disease prevention trials for individuals at short-term risk of developing ALS. Ann Neurol 2018 Ann Neurol 2018;83:130-139.

MiR126-5p Downregulation Facilitates Axon Degeneration and NMJ Disruption via a Non-Cell-Autonomous Mechanism in ALS.

Axon degeneration and disruption of neuromuscular junctions (NMJs) are key events in amyotrophic lateral sclerosis (ALS) pathology. Although the disease's etiology is not fully understood, it is thought to involve a non–cell-autonomous mechanism and alterations in RNA metabolism. Here, we identified reduced levels of miR126-5p in presymptomatic ALS male mice models, and an increase in its targets: axon destabilizing Type 3 Semaphorins and their coreceptor Neuropilins. Using compartmentalized in vitro cocultures, we demonstrated that myocytes expressing diverse ALS-causing mutations promote axon degeneration and NMJ dysfunction, which were inhibited by applying Neuropilin1 blocking antibody. Finally, overexpressing miR126-5p is sufficient to transiently rescue axon degeneration and NMJ disruption both in vitro and in vivo. Thus, we demonstrate a novel mechanism underlying ALS pathology, in which alterations in miR126-5p facilitate a non–cell-autonomous mechanism of motor neuron degeneration in ALS.SIGNIFICANCE STATEMENT Despite some progress, currently no effective treatment is available for amyotrophic lateral sclerosis (ALS). We suggest a novel regulatory role for miR126-5p in ALS and demonstrate, for the first time, a mechanism by which alterations in miR126-5p contribute to axon degeneration and NMJ disruption observed in ALS. We show that miR126-5p is altered in ALS models and that it can modulate Sema3 and NRP protein expression. Furthermore, NRP1 elevations in motor neurons and muscle secretion of Sema3A contribute to axon degeneration and NMJ disruption in ALS. Finally, overexpressing miR126-5p is sufficient to transiently rescue NMJ disruption and axon degeneration both in vitro and in vivo.

Metabolic Reprogramming in Amyotrophic Lateral Sclerosis

Mitochondrial dysfunction in the spinal cord is a hallmark of amyotrophic lateral sclerosis (ALS), but the neurometabolic alterations during early stages of the disease remain unknown. Here, we investigated the bioenergetic and proteomic changes in ALS mouse motor neurons and patients’ skin fibroblasts. We first observed that SODG93A mice presymptomatic motor neurons display alterations in the coupling efficiency of oxidative phosphorylation, along with fragmentation of the mitochondrial network. The proteome of presymptomatic ALS mice motor neurons also revealed a peculiar metabolic signature with upregulation of most energy-transducing enzymes, including the fatty acid oxidation (FAO) and the ketogenic components HADHA and ACAT2, respectively. Accordingly, FAO inhibition altered cell viability specifically in ALS mice motor neurons, while uncoupling protein 2 (UCP2) inhibition recovered cellular ATP levels and mitochondrial network morphology. These findings suggest a novel hypothesis of ALS bioenergetics linking FAO and UCP2. Lastly, we provide a unique set of data comparing the molecular alterations found in human ALS patients’ skin fibroblasts and SODG93A mouse motor neurons, revealing conserved changes in protein translation, folding and assembly, tRNA aminoacylation and cell adhesion processes.

Hypothalamic atrophy is related to body mass index and age at onset in amyotrophic lateral sclerosis

ObjectiveOur objective was to study the hypothalamic volume in a cohort of patients with amyotrophic lateral sclerosis (ALS) including symptomatic and presymptomatic ALS mutation carriers.MethodsHigh-resolution three-dimensional T1-weighted MRI datasets from...