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

From suspicion to diagnosis: exploration strategy for suspected amyotrophic lateral sclerosis

The diagnosis of amyotrophic lateral sclerosis (ALS) is based on evidence of upper and lower motor neuron degeneration in the bulbar, cervical, thoracic, and lumbar regions in a patient with progressive motor weakness, in the absence of differential diagnosis. Despite these well-defined criteria, ALS can be difficult to diagnose, given the wide variety of clinical phenotypes. Indeed, the central or peripheral location of the disease varies with a spectrum ranging from predominantly central to exclusively peripheral, symptoms can be extensive or limited to the limbs, bulbar area or respiratory muscles, and the duration of the disease may range from a few months to several decades. In the absence of a specific test, the diagnostic strategy relies on clinical, electrophysiological, biological and radiological investigations to confirm the disease and exclude ALS mimics. The main challenge is to establish a diagnosis based on robust clinical and paraclinical evidence without delaying treatment initiation by increasing the number of additional tests. This approach requires a thorough knowledge of the phenotypes of ALS and its main differential diagnoses.

Amyotrophic lateral sclerosis represents corticomotoneuronal system failure

Several decades have passed since the anterograde corticomotoneuronal hypothesis for amyotrophic lateral sclerosis (ALS) was proposed. The intervening years have witnessed its emergent support based on anatomical, pathological, physiological, neuroimaging, and molecular biological studies. The evolution of an extensive corticomotoneuronal system appears restricted to the human species, with ALS representing a uniquely human disease. While some, very select non-human primates have limited corticomotoneuronal projections, these tend to be absent in all other animals. From a general perspective, the early clinical features of ALS may be considered to reflect failure of the corticomotoneuronal system. The characteristic loss of skilled motor dexterity involving the limbs, and speech impairment through progressive bulbar dysfunction specifically involve those motor units having the strongest corticomotoneuronal projections. A similar explanation likely underlies the unique "split phenotypes" that have now been well characterized in ALS. Large Betz cells and other pyramidal corticomotoneuronal projecting neurons, with their extensive dendritic arborization, are particularly vulnerable to the elements of the ALS exposome such as aging, environmental stress and lifestyle changes. Progressive failure of the proteosome impairs nucleocytoplasmic shuffling and induces toxic but soluble TDP-43 to aggregate in corticomotoneurons. Betz cell failure is further accentuated through dysfunction of its profuse dendritic arborizations. Clarification of system specific genomes and neural networks will likely promote the initiation of precision medicine approaches directed to support the key structure that underlies the neurological manifestations of ALS, the corticomotoneuronal system.

Serum heat shock protein concentrations are not associated with amyotrophic lateral sclerosis risk or survival in three European populations

Introduction: Serum heat shock protein (HSP) concentrations have been reported as potential biomarkers for amyotrophic lateral sclerosis (ALS). Here, we investigate the role of serum HSP70, HSP90, and DNAJC7 as biomarkers for ALS. Methods: Serum samples were collected from ALS patients and volunteer controls from three different clinical cohorts (in Germany, Ireland, and Italy). Serum HSP concentrations were determined using enzyme-linked immunosorbent assay. Descriptive statistics, generalized logistic regression, and Cox proportional hazards models were used to model associations between log serum HSP concentrations and ALS risk. Results: In total, 251 ALS patients and 184 healthy volunteers were included. Logistic regression models failed to find associations between ALS risk and log serum concentration of HSP70 (OR 0.43, 95% CI: 0.10-1.78, p = 0.242), HSP90 (OR 0.95, 95% CI: 0.39-2.37, p = 0.904), or DNAJC7 (OR 1.55, 95% CI: 0.90-2.68, p = 0.118). Survival of ALS patients was not associated with log serum concentration of HSP HSP70 (HR1.06, 95% CI: 0.36-3.14, p = 0.916), HSP90 (HR 1.17, 95% CI: 0.67-2.02, p = 0.584), or DNAJC7 (HR 0.83, 95% CI: 0.57-1.21, p = 0.337). Discussion: We did not replicate previous findings that serum HSP70 and HSP90 concentrations were associated with risk of ALS. DNAJC7 was not associated with ALS risk, and there were no obvious longitudinal patterns in log serum concentrations of HSP70, HSP90, or DNAJC7. In addition, serum HSP concentrations were not associated with ALS survival.

Investigating the impact of socioeconomic status on amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the gradual death of motor neurons in the brain and spinal cord, leading to fatal paralysis. Socioeconomic status (SES) is a measure of an individual's shared economic and social status, which has been shown to have an association with health outcomes. Understanding the impact of SES on health conditions is crucial, as it can influence and be influenced by health-related variables. The role of socioeconomic status in influencing the risk and progression of ALS has not been established, and understanding the various factors that impact ALS is important in developing strategies for treatment and prevention. To investigate this relationship, we recruited 413 participants with definite, probable, or possible ALS according to the El Escorial criteria, from three tertiary centers in London, Sheffield, and Birmingham. Logistic regression was used to examine the association between case-control status, socioeconomic criteria, and ALS risk. Linear regression was used to examine the association between age of onset and socioeconomic variables. Two sensitivity analyses were performed, one using an alternative occupational classifier, and the other using Mendelian Randomization analysis to examine association. There was no significant relationship between any variables and ALS risk. We found an inverse relationship between mean lifetime salary and age of ALS onset (Beta = -0.157, p = 0.011), but no effect of education or occupation on the age of onset. The finding was confirmed in both sensitivity analyses and in Mendelian Randomization. We find that a higher salary is associated with a younger age of ALS onset taking into account sex, occupation, years of education, and clinical presentation.

Association Between Early-Life and Premorbid Measurements of Body Composition and Risk of Motor Neuron Disease: A Prospective Cohort Study in the UK Biobank

OBJECTIVE

The objective of this study was to investigate the association between developmental and premorbid body composition measurements and the risk of motor neuron disease (MND).

METHODS

We performed a cohort study in the UK Biobank to assess the association of developmental body metrics and premorbid body composition measures (using 28 measurements and 7 patterns of body composition) with the risk of MND. Among participants with longitudinal measures, we compared the changes in body composition over time between individuals who later developed MND and those who remained free of MND.

RESULTS

Among the 412,691 individuals included in this study, 549 people received an MND diagnosis during the follow-up visit. Higher birth weight was associated with an increased risk of MND among individuals born over 4 kg (hazard ratio [HR] per kg increase = 2.21, 95% confidence interval [CI] = 1.38-3.55), and taller adult height was associated with an increased risk of MND (HR per 5 cm increase = 1.10, 95% CI = 1.03-1.17). We observed that measures of elevated fat mass were associated with a lower risk of MND more than 5 years before diagnosis. A higher "leg-dominant fat distribution" pattern was associated with an increased risk whereas higher "muscle strength" was associated with a reduced risk of MND 5 years before diagnosis. Longitudinal analyses indicated a faster decline in measures of fat mass and muscle strength, as well as a shift in fat distribution from arm to leg dominant, among individuals who later developed MND, compared with others.

INTERPRETATION

Body composition at early and middle age may be indicative of the risk of MND development. ANN NEUROL 2024.

Skeletal myotubes expressing ALS mutant SOD1 induce pathogenic changes, impair mitochondrial axonal transport, and trigger motoneuron death

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of motoneurons (MNs), and despite progress, there is no effective treatment. A large body of evidence shows that astrocytes expressing ALS-linked mutant proteins cause non-cell autonomous toxicity of MNs. Although MNs innervate muscle fibers and ALS is characterized by the early disruption of the neuromuscular junction (NMJ) and axon degeneration, there are controversies about whether muscle contributes to non-cell-autonomous toxicity to MNs. In this study, we generated primary skeletal myotubes from myoblasts derived from ALS mice expressing human mutant SOD1G93A (termed hereafter mutSOD1). Characterization revealed that mutSOD1 skeletal myotubes display intrinsic phenotypic and functional differences compared to control myotubes generated from non-transgenic (NTg) littermates. Next, we analyzed whether ALS myotubes exert non-cell-autonomous toxicity to MNs. We report that conditioned media from mutSOD1 myotubes (mutSOD1-MCM), but not from control myotubes (NTg-MCM), induced robust death of primary MNs in mixed spinal cord cultures and compartmentalized microfluidic chambers. Our study further revealed that applying mutSOD1-MCM to the MN axonal side in microfluidic devices rapidly reduces mitochondrial axonal transport while increasing Ca2 + transients and reactive oxygen species (i.e., H2O2). These results indicate that soluble factor(s) released by mutSOD1 myotubes cause MN axonopathy that leads to lethal pathogenic changes.

Atomistic Insights into the Stabilization of TDP-43 Protofibrils by ATP

The aberrant accumulation of the transactive response deoxyribonucleic acid (DNA)-binding protein of 43 kDa (TDP-43) aggregates in the cytoplasm of motor neurons is the main pathological hallmark of amyotrophic lateral sclerosis (ALS). Previous experiments reported that adenosine triphosphate (ATP), the universal energy currency for all living cells, could induce aggregation and enhance the folding of TDP-43 fibrillar aggregates. However, the significance of ATP on TDP-43 fibrillation and the mechanism behind it remain elusive. In this work, we conducted multiple atomistic molecular dynamics (MD) simulations totaling 20 μs to search the critical nucleus size of TDP-43282-360 and investigate the impact of ATP molecules on preformed protofibrils. The results reveal that the trimer is the critical nucleus for TDP-43282-360 fibril formation and the tetramer is the minimal stable nucleus. When ATP molecules bind to the TDP-43282-360 trimer and tetramer, they can consolidate the TDP-43282-360 protofibrils by increasing the content of the β-sheet structure and promoting the formation of hydrogen bonds (H-bonds). Binding site analyses show that the N-terminus of TDP-43282-360 protofibrils is the main binding site of ATP, and R293 dominates the direct binding of ATP. Further analyses reveal that the π-π, cation-π, salt bridge, and H-bonding interactions together contribute to the binding of ATP to TDP-43282-360 protofibrils. This study decoded the detailed stabilization mechanism of protofibrillar TDP-43282-360 oligomers by ATP, and may provide new avenues for the development of drug design against ALS.

APE1: A critical focus in neurodegenerative conditions

The global growth of the aging population has resulted in an increased prevalence of neurodegenerative diseases, characterized by the progressive loss of central nervous system (CNS) structure and function. Given the high incidence and debilitating nature of neurodegenerative diseases, there is an urgent need to identify potential biomarkers and novel therapeutic targets thereof. Apurinic/apyrimidinic endonuclease 1 (APE1), has been implicated in several neurodegenerative diseases, as having a significant role. Abnormal APE1 expression has been observed in conditions including Alzheimer's disease, stroke, amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, and epilepsy. However, whether this dysregulation is protective or harmful remains unclear. This review aims to comprehensively review the current understanding of the involvement of APE1 in neurodegenerative diseases.

Copper homeostasis and cuproptosis in health and disease

Copper is a vital trace element in human physiology, essential for the synthesis of numerous crucial metabolic enzymes and facilitation of various biological processes. Regulation of copper levels within a narrow range is imperative for maintaining metabolic homeostasis. Numerous studies have demonstrated the significant roles of copper homeostasis and cuproptosis in health and disease pathogenesis. However, a comprehensive and up-to-date systematic review in this domain remains absent. This review aims to consolidate recent advancements in understanding the roles of cuproptosis and copper homeostasis in health and disease, focusing on the underlying mechanisms and potential therapeutic interventions. Dysregulation of copper homeostasis, manifesting as either copper excess or deficiency, is implicated in the etiology of various diseases. Cuproptosis, a recently identified form of cell death, is characterized by intracellular copper overload. This phenomenon mediates a diverse array of evolutionary processes in organisms, spanning from health to disease, and is implicated in genetic disorders, liver diseases, neurodegenerative disorders, and various cancers. This review provides a comprehensive summary of the pathogenic mechanisms underlying cuproptosis and copper homeostasis, along with associated targeted therapeutic agents. Furthermore, it explores future research directions with the potential to yield significant advancements in disease treatment, health management, and disease prevention.

Amyotrophic lateral sclerosis caused by the C9orf72 expansion in Norway - prevalence, ancestry, clinical characteristics and sociodemographic status

OBJECTIVE

The most common genetic cause of amyotrophic lateral sclerosis (ALS) is the C9orf72 expansion. A high incidence of this expansion has been detected in Sweden and Finland. This Norwegian population-based study aimed to identify the prevalence, geographic distribution, ancestry, and relatedness of ALS patients with a C9orf72 expansion (C9pos). Further, we compared C9pos and C9neg patients' clinical presentation, family history of ALS and other neurodegenerative disorders, and sociodemographic status.

METHODS

We recruited ALS patients from all 17 Departments of neurology in Norway. Blood samples and questionnaires regarding clinical characteristics, sociodemographic status and family history of ALS, and other neurodegenerative disorders were collected. The C9orf72 expansion was examined for all patients.

RESULTS

The study enrolled 500 ALS patients, 8.8% of whom were C9pos, with half being sporadic ALS cases. The proportion of C9pos cases differed between regions, ranging from 17.9% in the Northern region to 1.9% in the Western region. The majority of C9pos patients had non-Finnish European descent and were not closely related. C9pos patients exhibited a significantly shorter mean survival time, had a higher frequency of relatives with ALS or dementia, and were more often unmarried/single and childless than C9neg patients.

CONCLUSION

C9pos patients constitute a large portion of the Norwegian ALS population. Ancestry and relatedness do not adequately explain regional differences. Relying on clinical information to identify C9pos patients has proven to be challenging. Half of C9pos patients were reported as having sporadic ALS, underlining the importance of carefully assessing family history and the need for genetic testing.

Evaluation of a Synthetic Retinoid, Ellorarxine, in the NSC-34 Cell Model of Motor Neuron Disease

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease worldwide and is characterized by progressive muscle atrophy. There are currently two approved treatments, but they only relieve symptoms briefly and do not cure the disease. The main hindrance to research is the complex cause of ALS, with its pathogenesis not yet fully elucidated. Retinoids (vitamin A derivatives) appear to be essential in neuronal cells and have been implicated in ALS pathogenesis. This study explores 4-[2-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydroquinoxalin-2-yl)ethylnyl]benzoic acid (Ellorarxine, or DC645 or NVG0645), a leading synthetic retinoic acid, discussing its pharmacological mechanisms, neuroprotective properties, and relevance to ALS. The potential therapeutic effect of Ellorarxine was analyzed in vitro using the WT and SOD1G93A NSC-34 cell model of ALS at an administered concentration of 0.3-30 nM. Histological, functional, and biochemical analyses were performed. Elorarxine significantly increased MAP2 expression and neurite length, increased AMPA receptor GluA2 expression and raised intracellular Ca2+ baseline, increased level of excitability, and reduced Ca2+ spike during depolarization in neurites. Ellorarxine also displayed both antioxidant and anti-inflammatory effects. Overall, these results suggest Ellorarxine shows relevance and promise as a novel therapeutic strategy for treatment of ALS.

Occupational lead exposure and amyotrophic lateral sclerosis survival in the Danish National Patient Registry

OBJECTIVES

We investigated the relationship between occupational lead exposure and amyotrophic lateral sclerosis (ALS) survival in Denmark.

METHODS

We identified 2,161 ALS cases diagnosed from 1982 to 2013 with at least 5 years of employment history before ALS diagnosis, via the Danish National Patient Registry. Cases were followed until March 2017. We defined lead exposure as never employed in a lead job, ever employed in a lead job, and ever employed in a lead job by exposure probability (<50% vs. ≥50%), excluding jobs held in the 5 years before diagnosis in main analyses. Survival was evaluated using Cox proportional hazards models and stratified by sex and age of diagnosis.

RESULTS

Median age of diagnosis was 63.5 years, and individuals in lead-exposed jobs were diagnosed at a younger age. Adjusted hazard ratios (aHR) were slightly decreased for men ever lead-exposed (aHR:0.92, 95%CI: 0.80, 1.05) and more so among those diagnosed at age 60-69 (lead ≥ 50% aHR: 0.66, 95%CI: 0.45, 0.98), but reversed for men diagnosed at age 70 and later (aHR: 2.03, 95%CI: 1.13, 3.64). No apparent pattern was observed among women.

CONCLUSIONS

Occupational lead exposure contributed to shorter survival among men diagnosed at older ages. The inverse associations observed for men diagnosed earlier could relate to possible healthy worker hire effect or health advantages of working in lead-exposed jobs. Our results are consistent with an adverse impact of lead exposure on ALS survival at older ages, with the age at which lead's effects on survival worsen later on among those in lead-exposed jobs.

Expression Changes of miRNAs in Humans and Animal Models of Amyotrophic Lateral Sclerosis and Their Potential Application for Clinical Diagnosis

Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disease. Current detection methods can only confirm the diagnosis at the onset of the disease, missing the critical window for early treatment. Recent studies using animal models have found that detecting changes in miRNA sites can predict the onset and severity of the disease in its early stages, facilitating early diagnosis and treatment. miRNAs show expression changes in motor neurons that connect the brain, spinal cord, and brain stem, as well as in the skeletal muscle in mouse models of ALS. Clinically, expression changes in some miRNAs in patients align with those in mouse models, such as the upregulation of miR-29b in the brain and the upregulation of miR-206 in the skeletal muscle. This study provides an overview of some miRNA study findings in humans as well as in animal models, including SOD1, FUS, TDP-43, and C9orf72 transgenic mice and wobbler mice, highlighting the potential of miRNAs as diagnostic markers for ALS. miR-21 and miR-206 are aberrantly expressed in both mouse model and patient samples, positioning them as key potential diagnostic markers in ALS. Additionally, miR-29a, miR-29b, miR-181a, and miR-142-3p have shown aberrant expression in both types of samples and show promise as clinical targets for ALS. Finally, miR-1197 and miR-486b-5p have been recently identified as aberrantly expressed miRNAs in mouse models for ALS, although further studies are needed to determine their viability as diagnostic targets.

ALS-associated C21ORF2 variant disrupts DNA damage repair, mitochondrial metabolism, neuronal excitability and NEK1 levels in human motor neurons

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease leading to motor neuron loss. Currently mutations in > 40 genes have been linked to ALS, but the contribution of many genes and genetic mutations to the ALS pathogenic process remains poorly understood. Therefore, we first performed comparative interactome analyses of five recently discovered ALS-associated proteins (C21ORF2, KIF5A, NEK1, TBK1, and TUBA4A) which highlighted many novel binding partners, and both unique and shared interactors. The analysis further identified C21ORF2 as a strongly connected protein. The role of C21ORF2 in neurons and in the nervous system, and of ALS-associated C21ORF2 variants is largely unknown. Therefore, we combined human iPSC-derived motor neurons with other models and different molecular cell biological approaches to characterize the potential pathogenic effects of C21ORF2 mutations in ALS. First, our data show C21ORF2 expression in ALS-relevant mouse and human neurons, such as spinal and cortical motor neurons. Further, the prominent ALS-associated variant C21ORF2-V58L caused increased apoptosis in mouse neurons and movement defects in zebrafish embryos. iPSC-derived motor neurons from C21ORF2-V58L-ALS patients, but not isogenic controls, show increased apoptosis, and changes in DNA damage response, mitochondria and neuronal excitability. In addition, C21ORF2-V58L induced post-transcriptional downregulation of NEK1, an ALS-associated protein implicated in apoptosis and DDR. In all, our study defines the pathogenic molecular and cellular effects of ALS-associated C21ORF2 mutations and implicates impaired post-transcriptional regulation of NEK1 downstream of mutant C21ORF72 in ALS.

The presence and clinical significance of autoantibodies in amyotrophic lateral sclerosis: a narrative review

Amyotrophic lateral sclerosis (ALS) is a debilitating and rapidly fatal neurodegenerative disease, which is characterized by the selective loss of the upper and lower motor neurons. The pathogenesis of ALS remains to be elucidated and has been connected to genetic, environmental and immune conditions. Evidence from clinical and experimental studies has suggested that the immune system played an important role in ALS pathophysiology. Autoantibodies are essential components of the immune system. Several autoantibodies directed at antigens associated with ALS pathogenesis have been identified in the serum and/or cerebrospinal fluid of ALS patients. The aim of this review is to summarize the presence and clinical significance of autoantibodies in ALS.

Analysis and occurrence of biallelic pathogenic repeat expansions in RFC1 in a German cohort of patients with a main clinical phenotype of motor neuron disease

Biallelic pathogenic repeat expansions in RFC1 were recently identified as molecular origin of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) as well as of one of the most common causes of adult-onset ataxia. In the meantime, the phenotypic spectrum has expanded massively and now includes mimics of multiple system atrophy or parkinsonism. After identifying a patient with a clinical diagnosis of amyotrophic lateral sclerosis (ALS) as a carrier of biallelic pathogenic repeat expansions in RFC1, we studied a cohort of 106 additional patients with a clinical main phenotype of motor neuron disease (MND) to analyze whether such repeat expansions are more common in MND patients. Indeed, two additional MND patients (one also with ALS and one with primary lateral sclerosis/PLS) have been identified as carrier of biallelic pathogenic repeat expansions in RFC1 in the absence of another genetic alteration explaining the phenotype, suggesting motor neuron disease as another extreme phenotype of RFC1 spectrum disorder. Therefore, MND might belong to the expanding phenotypic spectrum of pathogenic RFC1 repeat expansions, particularly in those MND patients with additional features such as sensory and/or autonomic neuropathy, vestibular deficits, or cerebellar signs. By systematically analyzing the RFC1 repeat array using Oxford nanopore technology long-read sequencing, our study highlights the high intra- and interallelic heterogeneity of this locus and allows the identification of the novel repeat motif 'ACAAG'.

Exploring the impact of circular RNA on ALS progression: A systematic review

Amyotrophic lateral sclerosis is a neurodegenerative disease that damages motor neurons and causes gradual muscular weakening and paralysis. Although studies have linked a number of genetic and environmental factors to ALS, the specific causes and mechanisms of the disease are still unclear. The pivotal role of circular RNA in the pathogenesis of ALS is a newly emerging area of research. The term "circular RNA" describes a particular class of RNA molecule that, in contrast to most RNA molecules, has a closed-loop structure. According to recent research, circular RNA might be essential for the development and progression of ALS. It has been discovered that these circular RNAs support important cellular functions related to ALS, including protein turnover, mitochondrial function, RNA processing, and cellular transport. Gaining knowledge about the precise roles and processes of circular RNA in the development of ALS could assist in understanding the pathophysiology of the disease and possibly pave the way for the development of targeted therapies. However, the understanding of circular RNA in ALS is still limited, and more research is needed to fully elucidate its role. In order to gain a comprehensive understanding of the role of circRNAs in ALS, it is imperative to delve into the various mechanisms through which circRNAs may contribute to the development and progression of the disease. Examining the current status of circRNA research in ALS and offering insights into their potential as therapeutic targets and diagnostic markers are the primary objectives of this review.

The prion-like effect and prion-like protein targeting strategy in amyotrophic lateral sclerosis

Pathological proteins in amyotrophic lateral sclerosis (ALS), such as superoxide dismutase 1, TAR DNA-binding protein 43, and fused in sarcoma, exhibit a prion-like pattern. All these proteins have a low-complexity domain and seeding activity in cells. In this review, we summarize the studies on the prion-like effect of these proteins and list six prion-like protein targeting strategies that we believe have potential for ALS therapy, including antisense oligonucleotides, antibody-based technology, peptide, protein chaperone, autophagy enhancement, and heteromultivalent compounds. Considering the pathological complexity and heterogeneity of ALS, we believe that the final solution to ALS therapy is most likely to be an individualized cocktail therapy, including clearance of toxicity, blockage of pathological progress, and protection of neurons.

Exploring the Impact of Amyotrophic Lateral Sclerosis on Otolaryngological Functions

IMPORTANCE

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive degeneration of upper and lower motor neurons at the spinal or bulbar level.

OBJECTIVE

We aim to describe the most frequent otolaryngology (ORL) complaints and voice disturbances in patients with bulbar onset ALS.

DESIGN

Retrospective cohort study.

SETTING

Single-center study with combined ORL and ALS clinic evaluation.

PARTICIPANTS

Patients with a confirmed diagnosis of ALS following an ORL visit and who underwent comprehensive voice assessments between January 2021 and January 2023.

EXPOSURE

Objective voice assessments.

MAIN OUTCOMES AND MEASURES

Glottal functional index (GFI), voice handicap index (VHI), reflux system index (RSI), and voice quality characteristics such as shimmer, jitter, maximum phonation time (MPT), and other essential parameters were assessed.

RESULTS

One hundred and thirty-three patients (age 62.17 ± 10.79, 54.48% female) were included. Three patients were referred from the ORL department to the ALS clinic. The most frequent symptoms were; dysphagia, dysarthria, facial weakness, pseudobulbar affect, and sialorrhea. The mean of forced vital capacity was 59.85%, EAT-10 15.91 ± 11.66, RSI 25.84 ± 9.03, GFI 14.12 ± 5.58, VHI-10 42.81 ± 34.94, MPT 15.22 s ± 8.06. Many patients reported voice impairments mainly related to spastic dysarthria and the combination of lower and upper motor neuron dysarthria, hypernasality, reduced verbal expression, and articulatory accuracy. Shimmer was increased to 8.46% ± 7.20, and jitter to 2.26% ± 1.39.

CONCLUSIONS AND RELEVANCE

Based on our cohort, this population with bulbar onset ALS has a higher frequency of voice disturbance characterized by hypernasality, spastic dysarthria, and reduced verbal expression.

LEVEL OF EVIDENCE

Level 3.

Physical exercise in amyotrophic lateral sclerosis: a potential co-adjuvant therapeutic option to counteract disease progression

Amyotrophic lateral sclerosis (ALS) is a fatal disorder characterized by the selective degeneration of upper and lower motor neurons, leading to progressive muscle weakness and atrophy. The mean survival time is two to five years. Although the hunt for drugs has greatly advanced over the past decade, no cure is available for ALS yet. The role of intense physical activity in the etiology of ALS has been debated for several decades without reaching a clear conclusion. The benefits of organized physical activity on fitness and mental health have been widely described. Indeed, by acting on specific mechanisms, physical activity can influence the physiology of several chronic conditions. It was shown to improve skeletal muscle metabolism and regeneration, neurogenesis, mitochondrial biogenesis, and antioxidant defense. Interestingly, all these pathways are involved in ALS pathology. This review will provide a broad overview of the effect of different exercise protocols on the onset and progression of ALS, both in humans and in animal models. Furthermore, we will discuss challenges and opportunities to exploit physiological responses of imposed exercise training for therapeutic purposes.

Lifestyle and medical conditions in relation to ALS risk and progression-an introduction to the Swedish ALSrisc Study

BACKGROUND

This study was an introduction to the Swedish ALSrisc Study and explored the association of lifestyle and medical conditions, with risk and progression of amyotrophic lateral sclerosis (ALS).

METHODS

We included 265 newly diagnosed ALS patients during 2016-2022 in Stockholm and 207 ALS-free siblings and partners of the patients as controls. Information on body mass index (BMI), smoking, and history of head injuries, diabetes mellitus, hypercholesterolemia, and hypertension was obtained through the Euro-MOTOR questionnaire at recruitment. Patients were followed from diagnosis until death, invasive ventilation, or November 30, 2022.

RESULTS

Higher BMI at recruitment was associated with lower risk for ALS (OR 0.89, 95%CI 0.83-0.95), especially among those diagnosed after 65 years. One unit increase in the average BMI during the 3 decades before diagnosis was associated with a lower risk for ALS (OR 0.94, 95%CI 0.89-0.99). Diabetes was associated with lower risk of ALS (OR 0.38, 95%CI 0.16-0.90), while hypercholesterolemia was associated with higher risk of ALS (OR 2.10, 95%CI 1.13-3.90). Higher BMI at diagnosis was associated with lower risk of death (HR 0.91, 95%CI 0.84-0.98), while the highest level of smoking exposure (in pack-years) (HR 1.90, 95%CI 1.20-3.00), hypercholesterolemia (HR 1.84, 95%CI 1.06-3.19), and hypertension (HR 1.76, 95%CI 1.03-3.01) were associated with higher risk of death, following ALS diagnosis.

CONCLUSIONS

Higher BMI and diabetes were associated with lower risk of ALS. Higher BMI was associated with lower risk of death, whereas smoking (especially in high pack-years), hypercholesterolemia, and hypertension were associated with higher risk of death after ALS diagnosis.

T cell subset composition differs between blood and cerebrospinal fluid in amyotrophic lateral sclerosis

Inflammation is a hallmark of amyotrophic lateral sclerosis (ALS) and is often assessed through biological samples. Due to the easier access, peripheral blood is more commonly phenotyped instead of cerebrospinal fluid (CSF) or affected tissues in ALS. Here, using flow cytometry, we compared the composition of T cell subsets in blood and CSF in ALS patients. We found consistent but weak correlations between blood and CSF for all T cell subsets examined. This finding implies that blood and CSF offer complementary information when characterizing T cell immunity in ALS and blood may not be used as a surrogate for CSF.

Dissecting the effect of ALS mutation S375G on the conformational properties and aggregation dynamics of TDP-43370-375 fragment

The aggregation of transactive response deoxyribonucleic acid (DNA) binding protein of 43 kDa (TDP-43) into ubiquitin-positive inclusions is closely associated with amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration, and chronic traumatic encephalopathy. The 370-375 fragment of TDP-43 (370GNNSYS375, TDP-43370-375), the amyloidogenic hexapeptides, can be prone to forming pathogenic amyloid fibrils with the characteristic of steric zippers. Previous experiments reported the ALS-associated mutation, serine 375 substituted by glycine (S375G) is linked to early onset disease and protein aggregation of TDP-43. Based on this, it is necessary to explore the underlying molecular mechanisms. By utilizing all-atom molecular dynamics (MD) simulations of 102 μs in total, we investigated the impact of S375G mutation on the conformational ensembles and oligomerization dynamics of TDP-43370-375 peptides. Our replica exchange MD simulations show that S375G mutation could promote the unstructured conformation formation and induce peptides to form a loose packed oligomer, thus inhibiting the aggregation of TDP-43370-375. Further analyses suggest that S375G mutation displays a reduction effect on the number of total hydrogen bonds and contacts among TDP-43370-375 peptides. Hydrogen bonding and polar interactions among TDP-43370-375 peptides, as well as Y374-Y374 π-π stacking interaction, are attenuated by S375G mutation. Additional microsecond MD simulations demonstrate that S375G mutation could prohibit the conformational conversion to β-structure-rich aggregates and possess an inhibitory effect on the oligomerization dynamics of TDP-43370-375. This study offers for the first time of molecular insights into the S375G mutation affecting the aggregation of TDP-43370-375 at the atomic level, and may open new avenues in the development of future site-specific mutation therapeutics.

Update on recent advances in amyotrophic lateral sclerosis

In the last few years, our understanding of disease molecular mechanisms underpinning ALS has advanced greatly, allowing the first steps in translating into clinical practice novel research findings, including gene therapy approaches. Similarly, the recent advent of assistive technologies has greatly improved the possibility of a more personalized approach to supportive and symptomatic care, in the context of an increasingly complex multidisciplinary line of actions, which remains the cornerstone of ALS management. Against this rapidly growing background, here we provide an comprehensive update on the most recent studies that have contributed towards our understanding of ALS pathogenesis, the latest results from clinical trials as well as the future directions for improving the clinical management of ALS patients.

Mitigating the Functional Deficit after Neurotoxic Motoneuronal Loss by an Inhibitor of Mitochondrial Fission

Amyotrophic lateral sclerosis (ALS) is an extremely complex neurodegenerative disease involving different cell types, but motoneuronal loss represents its main pathological feature. Moreover, compensatory plastic changes taking place in parallel to neurodegeneration are likely to affect the timing of ALS onset and progression and, interestingly, they might represent a promising target for disease-modifying treatments. Therefore, a simplified animal model mimicking motoneuronal loss without the other pathological aspects of ALS has been established by means of intramuscular injection of cholera toxin-B saporin (CTB-Sap), which is a targeted neurotoxin able to kill motoneurons by retrograde suicide transport. Previous studies employing the mouse CTB-Sap model have proven that spontaneous motor recovery is possible after a subtotal removal of a spinal motoneuronal pool. Although these kinds of plastic changes are not enough to counteract the functional effects of the progressive motoneuron degeneration, it would nevertheless represent a promising target for treatments aiming to postpone ALS onset and/or delay disease progression. Herein, the mouse CTB-Sap model has been used to test the efficacy of mitochondrial division inhibitor 1 (Mdivi-1) as a tool to counteract the CTB-Sap toxicity and/or to promote neuroplasticity. The homeostasis of mitochondrial fission/fusion dynamics is indeed important for cell integrity, and it could be affected during neurodegeneration. Lesioned mice were treated with Mdivi-1 and then examined by a series of behavioral test and histological analyses. The results have shown that the drug may be capable of reducing functional deficits after the lesion and promoting synaptic plasticity and neuroprotection, thus representing a putative translational approach for motoneuron disorders.

Registration of Amyotrophic Lateral Sclerosis: Validity in the Danish National Patient Registry

Purpose

Health care databases are a valuable source for epidemiological research on amyotrophic lateral sclerosis (ALS) if diagnosis codes are valid. We evaluated the validity of the diagnostic codes for ALS in the Danish National Patient Registry (DNPR).

Patients and Methods

We obtained data from the DNPR for all adult (>17 years) patients registered with ALS in Denmark between 1987 and 2022 (median population of 4.2 million during the study period). We randomly selected adult patients living in the North Denmark Region and Central Denmark Region (median population 1.4 million), with a primary discharge diagnosis code of ALS, diagnosed at three departments of neurology. We retrieved and reviewed medical records and estimated the positive predictive value (PPV) of the ALS diagnosis.

Results

Over 36 years, we identified 5679 patients. From the validation cohort of 300 patients, we were able to retrieve 240 (80%) medical records, and 215 ALS diagnoses were confirmed. The overall positive predictive value was 89.6% (95% confidence interval (CI): 85.1-92.8). The highest PPV was achieved for diagnoses registered for patients aged ≥70 years (93.8; 95% CI: 86.2-97.3) compared to patients <60 years (83.4; 95% CI: 73.3-90.7).

Conclusion

We found a high PPV of primary diagnostic codes for ALS from Danish departments of neurology, demonstrating high validity. Thus, the DNPR is a well-suited data source for large-scale epidemiological research on ALS.

From Environment to Gene Expression: Epigenetic Methylations and One-Carbon Metabolism in Amyotrophic Lateral Sclerosis

The etiology of the neurodegenerative disease amyotrophic lateral sclerosis (ALS) is complex and considered multifactorial. The majority of ALS cases are sporadic, but familial cases also exist. Estimates of heritability range from 8% to 61%, indicating that additional factors beyond genetics likely contribute to ALS. Numerous environmental factors are considered, which may add up and synergize throughout an individual's lifetime building its unique exposome. One level of integration between genetic and environmental factors is epigenetics, which results in alterations in gene expression without modification of the genome sequence. Methylation reactions, targeting DNA or histones, represent a large proportion of epigenetic regulations and strongly depend on the availability of methyl donors provided by the ubiquitous one-carbon (1C) metabolism. Thus, understanding the interplay between exposome, 1C metabolism, and epigenetic modifications will likely contribute to elucidating the mechanisms underlying altered gene expression related to ALS and to developing targeted therapeutic interventions. Here, we review evidence for 1C metabolism alterations and epigenetic methylation dysregulations in ALS, with a focus on the impairments reported in neural tissues, and discuss these environmentally driven mechanisms as the consequences of cumulative exposome or late environmental hits, but also as the possible result of early developmental defects.

Complexity of needs in amyotrophic lateral sclerosis (ALS) patients using the ENP-E scale in the north-eastern region of Spain

OBJECTIVES

This study aimed to explore the clinical characteristics of amyotrophic lateral sclerosis (ALS) patients in Spain's north-eastern region, their inclusion in chronic care programmes, and their psychosocial and spiritual needs (PSNs).

METHODS

A longitudinal descriptive study in adult patients with ALS. We analyzed clinical variables and participation in chronicity and PSNs assessment using the tool Psychosocial and Spiritual Needs Evaluation scale in end-of-life patients (ENP-E scale).

RESULTS

81 patients (average age 65.6 ± 11.7) were studied. At the study's outset, 29.7% employed non-invasive ventilation (NIV), increasing to 51.9% by its conclusion. Initial percutaneous endoscopic gastrostomy (PEG) utilization was 14.8%, rising to 35.85%. Chronic care programme participation was as follows: home care (24.7% initially, 50.6% end), palliative care (16% initially, 40.7% end), case management (13.6% initially, 50.6% end), and advance care planning registration (6.2% initially, 35.8% end). At study start, 47.8% of patients (n = 46) showed moderate-to-severe complexity in PSNs assessment using the ENP-E scale, without showing differences in age, sex, and time of evolution; whereas, on the evolutionary analysis, it was 75% (n = 24). A higher evolutionary complexity was observed in males <60 and >70 years, with no PEG and evolution of ALS of <2 and ≥5 years, and not included in chronicity programmes. When assessing concerns, physical pain and family aspects stand out in all measurements. Forty-eight percent of patients at study start and 71% at end of study showed external signs of emotional distress.

SIGNIFICANCE OF RESULTS

Most ALS patients showed a high degree of complexity and were not integrated in chronicity programmes. A "care path" is proposed to integrate ALS patients in these programmes and systematically assess their needs.

Skeletal myotubes expressing ALS mutant SOD1 induce pathogenic changes, impair mitochondrial axonal transport, and trigger motoneuron death

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of motoneurons (MNs), and despite progress, there is no effective treatment. A large body of evidence shows that astrocytes expressing ALS-linked mutant proteins cause non-cell autonomous toxicity of MNs. Although MNs innervate muscle fibers and ALS is characterized by the early disruption of the neuromuscular junction (NMJ) and axon degeneration, there are controversies about whether muscle contributes to non-cell-autonomous toxicity to MNs. In this study, we generated primary skeletal myotubes from myoblasts derived from ALS mice expressing human mutant SOD1 G93A (termed hereafter mutSOD1). Characterization revealed that mutSOD1 skeletal myotubes display intrinsic phenotypic and functional differences compared to control myotubes generated from non-transgenic (NTg) littermates. Next, we analyzed whether ALS myotubes exert non-cell-autonomous toxicity to MNs. We report that conditioned media from mutSOD1 myotubes (mutSOD1-MCM), but not from control myotubes (NTg-MCM), induced robust death of primary MNs in mixed spinal cord cultures and compartmentalized microfluidic chambers. Our study further revealed that applying mutSOD1-MCM to the MN axonal side in microfluidic devices rapidly reduces mitochondrial axonal transport while increasing Ca2+ transients and reactive oxygen species (i.e., H 2 O 2 ). These results indicate that soluble factor(s) released by mutSOD1 myotubes cause MN axonopathy that leads to lethal pathogenic changes.

Protein aggregation and therapeutic strategies in SOD1- and TDP-43- linked ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with severe socio-economic impact. A hallmark of ALS pathology is the presence of aberrant cytoplasmic inclusions composed of misfolded and aggregated proteins, including both wild-type and mutant forms. This review highlights the critical role of misfolded protein species in ALS pathogenesis, particularly focusing on Cu/Zn superoxide dismutase (SOD1) and TAR DNA-binding protein 43 (TDP-43), and emphasizes the urgent need for innovative therapeutic strategies targeting these misfolded proteins directly. Despite significant advancements in understanding ALS mechanisms, the disease remains incurable, with current treatments offering limited clinical benefits. Through a comprehensive analysis, the review focuses on the direct modulation of the misfolded proteins and presents recent discoveries in small molecules and peptides that inhibit SOD1 and TDP-43 aggregation, underscoring their potential as effective treatments to modify disease progression and improve clinical outcomes.

From use of omics to systems biology: Identifying therapeutic targets for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a heterogeneous progressive neurodegenerative disorder with available treatments such as riluzole and edaravone extending survival by an average of 3-6 months. The lack of highly effective, widely available therapies reflects the complexity of ALS. Omics technologies, including genomics, transcriptomic and proteomics have contributed to the identification of biological pathways dysregulated and targeted by therapeutic strategies in preclinical and clinical trials. Integrating clinical, environmental and neuroimaging information with omics data and applying a systems biology approach can further improve our understanding of the disease with the potential to stratify patients and provide more personalised medicine. This chapter will review the omics technologies that contribute to a systems biology approach and how these components have assisted in identifying therapeutic targets. Current strategies, including the use of genetic screening and biosampling in clinical trials, as well as the future application of additional technological advances, will also be discussed.

Chimeric Cell Therapies as a Novel Approach for Duchenne Muscular Dystrophy (DMD) and Muscle Regeneration

Chimerism-based strategies represent a pioneering concept which has led to groundbreaking advancements in regenerative medicine and transplantation. This new approach offers therapeutic potential for the treatment of various diseases, including inherited disorders. The ongoing studies on chimeric cells prompted the development of Dystrophin-Expressing Chimeric (DEC) cells which were introduced as a potential therapy for Duchenne Muscular Dystrophy (DMD). DMD is a genetic condition that leads to premature death in adolescent boys and remains incurable with current methods. DEC therapy, created via the fusion of human myoblasts derived from normal and DMD-affected donors, has proven to be safe and efficacious when tested in experimental models of DMD after systemic-intraosseous administration. These studies confirmed increased dystrophin expression, which correlated with functional and morphological improvements in DMD-affected muscles, including cardiac, respiratory, and skeletal muscles. Furthermore, the application of DEC therapy in a clinical study confirmed its long-term safety and efficacy in DMD patients. This review summarizes the development of chimeric cell technology tested in preclinical models and clinical studies, highlighting the potential of DEC therapy in muscle regeneration and repair, and introduces chimeric cell-based therapies as a promising, novel approach for muscle regeneration and the treatment of DMD and other neuromuscular disorders.

Physiological and pathological effects of phase separation in the central nervous system

Phase separation, also known as biomolecule condensate, participates in physiological processes such as transcriptional regulation, signal transduction, gene expression, and DNA damage repair by creating a membrane-free compartment. Phase separation is primarily caused by the interaction of multivalent non-covalent bonds between proteins and/or nucleic acids. The strength of molecular multivalent interaction can be modified by component concentration, the potential of hydrogen, posttranslational modification, and other factors. Notably, phase separation occurs frequently in the cytoplasm of mitochondria, the nucleus, and synapses. Phase separation in vivo is dynamic or stable in the normal physiological state, while abnormal phase separation will lead to the formation of biomolecule condensates, speeding up the disease progression. To provide candidate suggestions for the clinical treatment of nervous system diseases, this review, based on existing studies, carefully and systematically represents the physiological roles of phase separation in the central nervous system and its pathological mechanism in neurodegenerative diseases.

Medication use and risk of amyotrophic lateral sclerosis: using machine learning for an exposome-wide screen of a large clinical database

BACKGROUND

Accumulating evidence suggests that non-genetic factors have important etiologic roles in amyotrophic lateral sclerosis (ALS), yet identification of specific culprit factors has been challenging. Many medications target biological pathways implicated in ALS pathogenesis, and screening large pharmacologic datasets for signals could greatly accelerate the identification of risk-modulating pharmacologic factors for ALS.

METHOD

We conducted a high-dimensional screening of patients' history of medication use and ALS risk using an advanced machine learning approach based on gradient-boosted decision trees coupled with Bayesian model optimization and repeated data sampling. Clinical and medication dispensing data were obtained from a large Israeli health fund for 501 ALS cases and 4,998 matched controls using a lag period of 3 or 5 years prior to ALS diagnosis for ascertaining medication exposure.

RESULTS

Of over 1,000 different medication classes, we identified 8 classes that were consistently associated with increased ALS risk across independently trained models, where most are indicated for control of symptoms implicated in ALS. Some suggestive protective effects were also observed, notably for vitamin E.

DISCUSSION

Our results indicate that use of certain medications well before the typically recognized prodromal period was associated with ALS risk. This could result because these medications increase ALS risk or could indicate that ALS symptoms can manifest well before suggested prodromal periods. The results also provide further evidence that vitamin E may be a protective factor for ALS. Targeted studies should be performed to elucidate the possible pathophysiological mechanisms while providing insights for therapeutics design.

Edaravone counteracts redox and metabolic disruptions in an emerging zebrafish model of sporadic ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which the death of motor neurons leads to loss of muscle function. Additionally, cognitive and circadian disruptions are common in ALS patients, contributing to disease progression and burden. Most ALS cases are sporadic, and environmental exposures contribute to their aetiology. However, animal models of these sporadic ALS cases are scarce. The small vertebrate zebrafish is a leading organism to model neurodegenerative diseases; previous studies have proposed bisphenol A (BPA) or β-methylamino-l-alanine (BMAA) exposure to model sporadic ALS in zebrafish, damaging motor neurons and altering motor responses. Here we characterise the face and predictive validity of sporadic ALS models, showing their potential for the mechanistic study of ALS drugs. We phenotypically characterise the BPA and BMAA-induced models, going beyond motor activity and motor axon morphology, to include circadian, redox, proteostasis, and metabolomic phenotypes, and assessing their predictive validity for ALS modelling. BPA or BMAA exposure induced concentration-dependent activity impairments. Also, exposure to BPA but not BMAA induced motor axonopathy and circadian alterations in zebrafish larvae. Our further study of the BPA model revealed loss of habituation to repetitive startles, increased oxidative damage, endoplasmic reticulum (ER) stress, and metabolome abnormalities. The BPA-induced model shows predictive validity, since the approved ALS drug edaravone counteracted BPA-induced motor phenotypes, ER stress, and metabolic disruptions. Overall, BPA exposure is a promising model of ALS-related redox and ER imbalances, contributing to fulfil an unmet need for validated sporadic ALS models.

Time from amyotrophic lateral sclerosis symptom onset to key disease milestones: analysis of data from a multinational cross-sectional survey

OBJECTIVE

To determine the average time from Amyotrophic Lateral Sclerosis (ALS) symptom onset to 11 pre-defined milestones, overall and according to ALS progression rate and geographic location.

METHODS

Data were drawn from the Adelphi Real World ALS Disease-Specific ProgrammeTM, a point-in-time survey of neurologists caring for people living with ALS (pALS) conducted in France, Germany, Italy, Spain, the United Kingdom and the United States from 2020-2021. ALS progression rate was calculated using time since symptom onset and ALS Functional Rating Scale Revised score.

RESULTS

Survey results were available for N = 1003 pALS (progression rate for N = 867). Mean time from symptom onset was 3.8 months to first consultation, 8.0 months to diagnosis, 16.2 months to employment change (part-time/sick leave/retirement/unemployment), 17.5 months to use of a walking aid, 18.5 months to first occurrence of caregiver support, 22.8 months to use of a wheelchair, 24.6 months to use of a communication aid, 27.3 months to use of a respiratory aid, 28.6 months to use of gastrostomy feeding, 29.7 months to use of eye gaze technology and 30.3 months to entering a care facility. Multivariate analysis indicated significant effects of fast (versus slow) progression rate on time to reach all 11 milestones, as well as US (versus European) location, age, body mass index and bulbar onset (versus other) on time to reach milestones.

CONCLUSIONS

pALS rapidly reached clinical and disease-related milestones within 30 months from symptom onset. Milestones were reached significantly faster by pALS with fast versus slow progression. Geographic differences were observed.

Desloratadine alleviates ALS-like pathology in hSOD1G93A mice via targeting 5HTR2A on activated spinal astrocytes

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with progressive loss of motor neurons in the spinal cord, cerebral cortex and brain stem. ALS is characterized by gradual muscle atrophy and dyskinesia. The limited knowledge on the pathology of ALS has impeded the development of therapeutics for the disease. Previous studies have shown that autophagy and astrocyte-mediated neuroinflammation are involved in the pathogenesis of ALS, while 5HTR2A participates in the early stage of astrocyte activation, and 5HTR2A antagonism may suppress astrocyte activation. In this study, we evaluated the therapeutic effects of desloratadine (DLT), a selective 5HTR2A antagonist, in human SOD1G93A (hSOD1G93A) ALS model mice, and elucidated the underlying mechanisms. HSOD1G93A mice were administered DLT (20 mg·kg-1·d-1, i.g.) from the age of 8 weeks for 10 weeks or until death. ALS onset time and lifespan were determined using rotarod and righting reflex tests, respectively. We found that astrocyte activation accompanying with serotonin receptor 2 A (5HTR2A) upregulation in the spinal cord was tightly associated with ALS-like pathology, which was effectively attenuated by DLT administration. We showed that DLT administration significantly delayed ALS symptom onset time, prolonged lifespan and ameliorated movement disorders, gastrocnemius injury and spinal motor neuronal loss in hSOD1G93A mice. Spinal cord-specific knockdown of 5HTR2A by intrathecal injection of adeno-associated virus9 (AAV9)-si-5Htr2a also ameliorated ALS pathology in hSOD1G93A mice, and occluded the therapeutic effects of DLT administration. Furthermore, we demonstrated that DLT administration promoted autophagy to reduce mutant hSOD1 levels through 5HTR2A/cAMP/AMPK pathway, suppressed oxidative stress through 5HTR2A/cAMP/AMPK/Nrf2-HO-1/NQO-1 pathway, and inhibited astrocyte neuroinflammation through 5HTR2A/cAMP/AMPK/NF-κB/NLRP3 pathway in the spinal cord of hSOD1G93A mice. In summary, 5HTR2A antagonism shows promise as a therapeutic strategy for ALS, highlighting the potential of DLT in the treatment of the disease. DLT as a 5HTR2A antagonist effectively promoted autophagy to reduce mutant hSOD1 level through 5HTR2A/cAMP/AMPK pathway, suppressed oxidative stress through 5HTR2A/cAMP/AMPK/Nrf2-HO-1/NQO-1 pathway, and inhibited astrocytic neuroinflammation through 5HTR2A/cAMP/AMPK/NF-κB/NLRP3 pathway in the spinal cord of hSOD1G93A mice.

Genetics screening in an Italian cohort of patients with Amyotrophic Lateral Sclerosis: the importance of early testing and its implication

INTRODUCTION

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease with an elusive etiology. While environmental factors have been considered, familial ALS cases have raised the possibility of genetic involvement. This genetic connection is increasingly evident, even in patients with sporadic ALS. We allowed access to the genetic test to all patients attending our clinic to identify the prevalence and the role of genetic variants in the development of the disease and to identify patients with potentially treatable forms of the disease.

MATERIALS AND METHODS

194 patients with probable or definite ALS, were enrolled. A comprehensive genetic testing was performed, including sequencing all exons of the SOD1 gene and testing for hexanucleotide intronic repeat expansions (G4C2) in the C9orf72 gene using fluorescent repeat-primed PCR (RP-PCR). Whole Exome NGS Sequencing (WES) was performed, followed by an in silico multigene panel targeting neuromuscular diseases, spastic paraplegia, and motor distal neuropathies. We conducted statistical analyses to compare different patient groups.

RESULTS

Clinically significant pathogenetic variants were detected in 14.43% of cases. The highest prevalence of pathogenetic variants was observed in fALS patients, but a substantial proportion of sALS patients also displayed at least one variant, either pathogenetic or of uncertain significance (VUS). The most observed pathogenetic variant was the expansion of the C9orf72 gene, which was associated with a shorter survival. SOD1 variants were found in 1.6% of fALS and 2.5% of sALS patients.

DISCUSSION

The study reveals a significant number of ALS patients carrying pathogenic or likely pathogenic variants, with a higher prevalence in familial ALS cases. The expansion of the C9orf72 gene emerges as the most common genetic cause of ALS, affecting familial and sporadic cases. Additionally, SOD1 variants are detected at an unexpectedly higher rate, even in patients without a familial history of ALS, underscoring the crucial role of genetic testing in treatment decisions and potential participation in clinical trials. We also investigated variants in genes such as TARDBP, FUS, NEK1, TBK1, and DNAJC7, shedding light on their potential involvement in ALS. These findings underscore the complexity of interpreting variants of uncertain significance (VUS) and their ethical implications in patient communication and genetic counseling for patients' relatives.

CONCLUSION

This study emphasizes the diverse genetic basis of ALS and advocates for integrating comprehensive genetic testing into diagnostic protocols. The evolving landscape of genetic therapies requires identifying all eligible patients transcending traditional familial boundaries. The presence of VUS highlights the multifaceted nature of ALS genetics, prompting further exploration of complex interactions among genetic variants, environmental factors, and disease development.

The pathogenic mechanism of TAR DNA-binding protein 43 (TDP-43) in amyotrophic lateral sclerosis

The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex, basal ganglia, brainstem, and spinal cord, and commonly involves the muscles of the upper and/or lower extremities, and the muscles of the bulbar and/or respiratory regions. However, as the disease progresses, it affects the adjacent body regions, leading to generalized muscle weakness, occasionally along with memory, cognitive, behavioral, and language impairments; respiratory dysfunction occurs at the final stage of the disease. The disease has a complicated pathophysiology and currently, only riluzole, edaravone, and phenylbutyrate/taurursodiol are licensed to treat amyotrophic lateral sclerosis in many industrialized countries. The TAR DNA-binding protein 43 inclusions are observed in 97% of those diagnosed with amyotrophic lateral sclerosis. This review provides a preliminary overview of the potential effects of TAR DNA-binding protein 43 in the pathogenesis of amyotrophic lateral sclerosis, including the abnormalities in nucleoplasmic transport, RNA function, post-translational modification, liquid-liquid phase separation, stress granules, mitochondrial dysfunction, oxidative stress, axonal transport, protein quality control system, and non-cellular autonomous functions (e.g., glial cell functions and prion-like propagation).

Incidence of amyotrophic lateral sclerosis-associated genetic variants: a clinic-based study

OBJECTIVE

This study is to determine the incidence of genetic forms of amyotrophic lateral sclerosis (ALS) in clinic-based population.

METHODS

Next-generation sequencing (NGS) of whole exome sequencing (WES) was conducted among a total of 374 patients with definite or probable ALS to identify ALS-associated genes based on ALSoD database ( https://alsod.ac.uk ) [2023-07-01].

RESULTS

Variants of ALS-associated genes were detected in 54.01% (202/374) ALS patients, among which 8.29% (31/374) were pathogenic/likely pathogenic (P/LP). The detection rates of P/LP variants were significantly higher in familial ALS than sporadic ALS (42.31% vs 5.75%, p < 0.001), while VUS mutations were more commonly detected in sporadic ALS (23.07% vs 47.13%, p = 0.018). There is no significant difference in detection rate between patients with and without early onset (8.93% vs 7.77%), rapid progression (9.30% vs 8.91%), cognitive decline (15.00% vs 7.93%), and cerebellar ataxia (20.00% vs 8.15%) (p > 0.05).

CONCLUSION

Over half of our ALS patients carried variants of ALS-related genes, most of which were variants of uncertain significance (VUS). Family history of ALS could work as strong evidence for carrying P/LP variants regarding ALS. There was no additionally suggestive effect of indicators including early onset, progression rate, cognitive decline, or cerebellar ataxia on the recommendation of genetic testing in clinical practice.

Traumatic injury causes selective degeneration and TDP-43 mislocalization in human iPSC-derived C9orf72-associated ALS/FTD motor neurons

A hexanucleotide repeat expansion (HRE) in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, patients with the HRE exhibit a wide disparity in clinical presentation and age of symptom onset suggesting an interplay between genetic background and environmental stressors. Neurotrauma as a result of traumatic brain or spinal cord injury has been shown to increase the risk of ALS/FTD in epidemiological studies. Here, we combine patient-specific induced pluripotent stem cells (iPSCs) with a custom-built device to deliver biofidelic stretch trauma to C9orf72 patient and isogenic control motor neurons (MNs) in vitro. We find that mutant but not control MNs exhibit selective degeneration after a single incident of severe trauma, which can be partially rescued by pretreatment with a C9orf72 antisense oligonucleotide. A single incident of mild trauma does not cause degeneration but leads to cytoplasmic accumulation of TDP-43 in C9orf72 MNs. This mislocalization, which only occurs briefly in isogenic controls, is eventually restored in C9orf72 MNs after 6 days. Lastly, repeated mild trauma ablates the ability of patient MNs to recover. These findings highlight alterations in TDP-43 dynamics in C9orf72 ALS/FTD patient MNs following traumatic injury and demonstrate that neurotrauma compounds neuropathology in C9orf72 ALS/FTD. More broadly, our work establishes an in vitro platform that can be used to interrogate the mechanistic interactions between ALS/FTD and neurotrauma.

Premorbid brain structure influences risk of amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a disease of the motor network associated with brain structure and functional connectivity alterations that are implicated in disease progression. Whether such changes have a causal role in ALS, fitting with a postulated influence of premorbid cerebral architecture on the phenotypes associated with neurodegenerative disorders is not known.

METHODS

This study considered causal effects and shared genetic risk of 2240 structural and functional MRI brain scan imaging-derived phenotypes (IDPs) on ALS using two sample Mendelian randomisation, with putative associations further examined with extensive sensitivity analysis. Shared genetic predisposition between IDPs and ALS was explored using genetic correlation analysis.

RESULTS

Increased white matter volume in the cerebral hemispheres was causally associated with ALS. Weaker causal associations were observed for brain stem grey matter volume, parieto-occipital white matter surface and volume of the left thalamic ventral anterior nucleus. Genetic correlation was observed between ALS and intracellular volume fraction and isotropic free water volume fraction within the posterior limb of the internal capsule.

CONCLUSIONS

This study provides evidence that premorbid brain structure, in particular white matter volume, contributes to the risk of ALS.

The glymphatic system and Amyotrophic lateral sclerosis

The glymphatic system and the meningeal lymphatic vessels provide a pathway for transport of solutes and clearance of toxic material from the brain. Of specific relevance to ALS, this is applicable for TDP-43 and glutamate, both major elements in disease pathogenesis. Flow is propelled by arterial pulsation, respiration, posture, as well as the positioning and proportion of aquaporin-4 channels (AQP4). Non-REM slow wave sleep is the is key to glymphatic drainage which discontinues during wakefulness. In Parkinson's disease and Alzheimer's disease, sleep impairment is known to predate the development of characteristic clinical features by several years and is associated with progressive accumulation of toxic proteinaceous products. While sleep issues are well described in ALS, consideration of preclinical sleep impairment or the potential of a failing glymphatic system in ALS has rarely been considered. Here we review how the glymphatic system may impact ALS. Preclinical sleep impairment as an unrecognized major risk factor for ALS is considered, while potential therapeutic options to improve glymphatic flow are explored.

The prognostic value of systematic genetic screening in amyotrophic lateral sclerosis patients

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with complex genetic architecture. Emerging evidence has indicated comorbidity between ALS and autoimmune conditions, suggesting a potential shared genetic basis. The objective of this study is to assess the prognostic value of systematic screening for rare deleterious mutations in genes associated with ALS and aberrant inflammatory responses.

METHODS

A discovery cohort of 494 patients and a validation cohort of 69 patients were analyzed in this study, with population-matched healthy subjects (n = 4961) served as controls. Whole exome sequencing (WES) was performed to identify rare deleterious variants in 50 ALS genes and 1177 genes associated with abnormal inflammatory responses. Genotype-phenotype correlation was assessed, and an integrative prognostic model incorporating genetic and clinical factors was constructed.

RESULTS

In the discovery cohort, 8.1% of patients carried confirmed ALS variants, and an additional 15.2% of patients carried novel ALS variants. Gene burden analysis revealed 303 immune-implicated genes with enriched rare variants, and 13.4% of patients harbored rare deleterious variants in these genes. Patients with ALS variants exhibited a more rapid disease progression (HR 2.87 [95% CI 2.03-4.07], p < 0.0001), while no significant effect was observed for immune-implicated variants. The nomogram model incorporating genetic and clinical information demonstrated improved accuracy in predicting disease outcomes (C-index, 0.749).

CONCLUSION

Our findings enhance the comprehension of the genetic basis of ALS within the Chinese population. It also appears that rare deleterious mutations occurring in immune-implicated genes exert minimal influence on the clinical trajectories of ALS patients.

Neurotoxicity of Pyrethroids in neurodegenerative diseases: From animals' models to humans' studies

Neurodegenerative diseases are associated with diverse symptoms, both motor and mental. Genetic and environmental factors can trigger neurodegenerative diseases. Chemicals as pesticides are constantly used in agriculture and also domestically. In this regard, pyrethroids (PY), are a class of insecticides in which its main mechanism of action is through disruption of voltage-dependent sodium channels function in insects. However, in mammals, they can also induce oxidative stress and enzyme dysfunction. This review investigates the association between PY and neurodegenerative diseases as Alzheimer's, Huntington's, Parkinson's, Amyotrophic Lateral Sclerosis, and Autism in animal models and humans. Published works using specific and non-specific models for these diseases were selected. We showed a tendency toward the development and/or aggravating of these neurodegenerative diseases following exposure to PYs. In animal models, the biochemical mechanisms of the diseases and their interaction with the insecticides are more deeply investigated. Nonetheless, only a few studies considered the specific model for each type of disease to analyze the impacts of the exposure. The choice of a specific model during the research is an important step and our review highlights the knowledge gaps of PYs effects using these models reinforcing the importance of them during the design of the experiments.

Development of novel treatments for amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that causes paralysis whose etiology and pathogenesis have not been fully elucidated. Presently it is incurable and rapidly progressive with a survival of 2-5 years from onset, and no treatments could cure it. Therefore, it is urgent to identify which therapeutic target(s) are more promising to develop treatments that could effectively treat ALS. So far, more than 90 novel treatments for ALS patients have been registered on ClinicalTrials.gov, of which 23 are in clinical trials, 12 have been terminated and the rest suspended. This review will systematically summarize the possible targets of these novel treatments under development or failing based on published literature and information released by sponsors, so as to provide basis and support for subsequent drug research and development.

Generation of human iPSC-derived phrenic-like motor neurons to model respiratory motor neuron degeneration in ALS

The fatal motor neuron (MN) disease Amyotrophic Lateral Sclerosis (ALS) is characterized by progressive MN degeneration. Phrenic MNs (phMNs) controlling the activity of the diaphragm are prone to degeneration in ALS, leading to death by respiratory failure. Understanding of the mechanisms of phMN degeneration in ALS is limited, mainly because human experimental models to study phMNs are lacking. Here we describe a method enabling the derivation of phrenic-like MNs from human iPSCs (hiPSC-phMNs) within 30 days. This protocol uses an optimized combination of small molecules followed by cell-sorting based on a cell-surface protein enriched in hiPSC-phMNs, and is highly reproducible using several hiPSC lines. We show further that hiPSC-phMNs harbouring ALS-associated amplification of the C9orf72 gene progressively lose their electrophysiological activity and undergo increased death compared to isogenic controls. These studies establish a previously unavailable protocol to generate human phMNs offering a disease-relevant system to study mechanisms of respiratory MN dysfunction.

TUBA4A downregulation as observed in ALS post-mortem motor cortex causes ALS-related abnormalities in zebrafish

Disease-associated variants of TUBA4A (alpha-tubulin 4A) have recently been identified in familial ALS. Interestingly, a downregulation of TUBA4A protein expression was observed in familial as well as sporadic ALS brain tissue. To investigate whether a decreased TUBA4A expression could be a driving factor in ALS pathogenesis, we assessed whether TUBA4A knockdown in zebrafish could recapitulate an ALS-like phenotype. For this, we injected an antisense oligonucleotide morpholino in zebrafish embryos targeting the zebrafish TUBA4A orthologue. An antibody against synaptic vesicle 2 was used to visualize motor axons in the spinal cord, allowing the analysis of embryonic ventral root projections. Motor behavior was assessed using the touch-evoked escape response. In post-mortem ALS motor cortex, we observed reduced TUBA4A levels. The knockdown of the zebrafish TUBA4A orthologue induced a motor axonopathy and a significantly disturbed motor behavior. Both phenotypes were dose-dependent and could be rescued by the addition of human wild-type TUBA4A mRNA. Thus, TUBA4A downregulation as observed in ALS post-mortem motor cortex could be modeled in zebrafish and induced a motor axonopathy and motor behavior defects reflecting a motor neuron disease phenotype, as previously described in embryonic zebrafish models of ALS. The rescue with human wild-type TUBA4A mRNA suggests functional conservation and strengthens the causal relation between TUBA4A protein levels and phenotype severity. Furthermore, the loss of TUBA4A induces significant changes in post-translational modifications of tubulin, such as acetylation, detyrosination and polyglutamylation. Our data unveil an important role for TUBA4A in ALS pathogenesis, and extend the relevance of TUBA4A to the majority of ALS patients, in addition to cases bearing TUBA4A mutations.