Amyotrophic lateral sclerosis: Current perspectives from basic research to the clinic

Knockdown of tgfb1a partially improves ALS phenotype in a transient zebrafish model

Amyotrophic lateral sclerosis (ALS) corresponds to a neurodegenerative disorder marked by the progressive degeneration of both upper and lower motor neurons located in the brain, brainstem, and spinal cord. ALS can be broadly categorized into two main types: sporadic ALS (sALS), which constitutes approximately 90% of all cases, and familial ALS (fALS), which represents the remaining 10% of cases. Transforming growth factor type-β (TGF-β) is a cytokine involved in various cellular processes and pathological contexts, including inflammation and fibrosis. Elevated levels of TGF-β have been observed in the plasma and cerebrospinal fluid (CSF) of both ALS patients and mouse models. In this perspective, we explore the impact of the TGF-β signaling pathway using a transient zebrafish model for ALS. Our findings reveal that the knockdown of tgfb1a lead to a partial prevention of motor axon abnormalities and locomotor deficits in a transient ALS zebrafish model at 48 h post-fertilization (hpf). In this context, we delve into the proposed distinct roles of TGF-β in the progression of ALS. Indeed, some evidence suggests a dual role for TGF-β in ALS progression. Initially, it seems to exert a neuroprotective effect in the early stages, but paradoxically, it may contribute to disease progression in later stages. Consequently, we suggest that the TGF-β signaling pathway emerges as an attractive therapeutic target for treating ALS. Nevertheless, further research is crucial to comprehensively understand the nuanced role of TGF-β in the pathological context.

Murine experimental models of amyotrophic lateral sclerosis: an update

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease whose aetiology is unknown. It is characterised by upper and lower motor neuron degeneration. Approximately 90% of cases of ALS are sporadic, whereas the other 10% are familial. Regardless of whether the case is familial o sporadic, patients will develop progressive weakness, muscle atrophy with spasticity, and muscle contractures. Life expectancy of these patients is generally 2 to 5 years after diagnosis.

DEVELOPMENT

In vivo models have helped to clarify the aetiology and pathogenesis of ALS, as well as the mechanisms of the disease. However, as these mechanisms are not yet fully understood, experimental models are essential to the continued study of the pathogenesis of ALS, as well as in the search for possible therapeutic targets. Although 90% of cases are sporadic, most of the models used to study ALS pathogenesis are based on genetic mutations associated with the familial form of the disease; the pathogenesis of sporadic ALS remains unknown. Therefore, it would be critical to establish models based on the sporadic form.

CONCLUSIONS

This article reviews the main genetic and sporadic experimental models used in the study of this disease, focusing on those that have been developed using rodents.

ICA-27243 improves neuromuscular function and preserves motoneurons in the transgenic SOD1G93A mice

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the death of upper and lower motor neurons (MNs). Excessive neuronal excitability has been implicated in MN degeneration; thus, modulation of hyperexcitability appears as a promising therapeutic strategy. Potassium channels are attractive targets since they can be activated at subthreshold voltages and can regulate neuronal excitability. In this study, we assayed the effects of N-(6-Chloro-pyridin-3-yl)-3,4-difluorobenzamide compound, known as ICA-27243, as a potential treatment for ALS. ICA-27243 is a highly selective Kv7.2/7.3 opener used mainly in epilepsy models. In the in vitro model of spinal cord organotypic cultures (SCOCs) exposed to acute excitotoxicity, ICA-27243 prevented MN degeneration at a dose-of 10 ​μM. Administration of ICA-27243 to transgenic SOD1G93A ALS mice improved the decline of neuromuscular function, maintained locomotion and coordination in the rotarod, decreased spinal MN death and attenuated glial reactivity. In conclusion, we report here for the first time that ICA-27243 is an effective treatment for ALS, emphasizing the potential of targeting Kv channels to reduce neuronal hyperexcitability.

In Silico Analyses of a Promising Drug Candidate for the Treatment of Amyotrophic Lateral Sclerosis Targeting Superoxide Dismutase I Protein

Amyotrophic lateral sclerosis (ALS) is the most prevalent motor neuron disorder in adults, which is associated with a highly disabling condition. To date, ALS remains incurable, and the only drugs approved by the FDA for its treatment confer a limited survival benefit. Recently, SOD1 binding ligand 1 (SBL-1) was shown to inhibit in vitro the oxidation of a critical residue for SOD1 aggregation, which is a central event in ALS-related neurodegeneration. In this work, we investigated the interactions between SOD1 wild-type and its most frequent variants, i.e., A4V (NP_000445.1:p.Ala5Val) and D90A (NP_000445.1:p.Asp91Val), with SBL-1 using molecular dynamics (MD) simulations. The pharmacokinetics and toxicological profile of SBL-1 were also characterized in silico. The MD results suggest that the complex SOD1-SBL-1 remains relatively stable and interacts within a close distance during the simulations. This analysis also suggests that the mechanism of action proposed by SBL-1 and its binding affinity to SOD1 may be preserved upon mutations A4V and D90A. The pharmacokinetics and toxicological assessments suggest that SBL-1 has drug-likeness characteristics with low toxicity. Our findings, therefore, suggested that SBL-1 may be a promising strategy to treat ALS based on an unprecedented mechanism, including for patients with these frequent mutations.

Different saccadic profile in bulbar versus spinal-onset amyotrophic lateral sclerosis

Two clinical phenotypes characterize the onset of amyotrophic lateral sclerosis (ALS): the spinal variant, with symptoms beginning in the limbs, and the bulbar variant, affecting firstly speech and swallowing. The two variants show some distinct features in the histopathology, localization and prognosis, but to which extent they really differ clinically and pathologically remains to be clarified. Recent neuropathological and neuroimaging studies have suggested a broader spreading of the neurodegenerative process in ALS, extending beyond the motor areas, toward other cortical and deep grey matter regions, many of which are involved in visual processing and saccadic control. Indeed, a wide range of eye movement deficits have been reported in ALS, but they have never been used to distinguish the two ALS variants. Since quantifying eye movements is a very sensitive and specific method for the study of brain networks, we compared different saccadic and visual search behaviours across spinal ALS patients (n = 12), bulbar ALS patients (n = 6) and healthy control subjects (n = 13), along with cognitive and MRI measures, with the aim to define more accurately the two patients subgroups and possibly clarify a different underlying neural impairment. We found separate profiles of visually-guided saccades between spinal (short saccades) and bulbar (slow saccades) ALS, which could result from the pathologic involvement of different pathways. We suggest an early involvement of the parieto-collicular-cerebellar network in spinal ALS and the fronto-brainstem circuit in bulbar ALS. Overall, our data confirm the diagnostic value of the eye movements analysis in ALS and add new insight on the involved neural networks.

Analysis of SOD1 and C9orf72 mutations in patients with amyotrophic lateral sclerosis in Antioquia, Colombia

INTRODUCTION

Amyotrophic lateral sclerosis is a neurodegenerative disease with a possible multifactorial origin characterized by the progressive degeneration of motor neurons. There is a relatively high prevalence of this disease in Antioquia; however, there is no published genetic study to date in Colombia. Despite its unknown etiopathogenesis, more genetic risk factors possibly involved in the development of this disease are constantly found.

OBJETIVES

To evaluate G93A and D90A mutations in SOD1 gene and a short tandem repeat in C9orf72 within a cohort of amyotrophic lateral sclerosis patients from Antioquia, Colombia. Materials y methods: Thirty-four patients previously diagnosed with amyotrophic lateral sclerosis were included in the study. Peripheral blood samples were used for DNA extraction and genotyping.

RESULTS

No mutations were found in SOD1 (G93A and D90A) in any of the patients, while C9orf72 exhibited an allele with a statistically significant high prevalence in the study sample (8 hexanucleotide repeats of CAGCAG).

CONCLUSIONS

These results suggest an association between this short tandem repeat (STR) in C9orf72 and the presence of amyotrophic lateral sclerosis in the studied population. However, this association should be established in a larger sample size and with controls from the same population. In addition, there also seems to be a genetic anticipation effect for the disease regarding this locus, since patients with this genotype present an earlier onset.

Patching Up the Permeability: The Role of Stem Cells in Lessening Neurovascular Damage in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a debilitating disease with poor prognosis. The pathophysiology of ALS is commonly debated, with theories involving inflammation, glutamate excitotoxity, oxidative stress, mitochondria malfunction, neurofilament accumulation, inadequate nutrients or growth factors, and changes in glial support predominating. These underlying pathological mechanisms, however, act together to weaken the blood brain barrier and blood spinal cord barrier, collectively considered as the blood central nervous system barrier (BCNSB). Altering the impermeability of the BCNSB impairs the neurovascular unit, or interdependent relationship between the brain and advances the concept that ALS is has a significant neurovascular component contributing to its degenerative presentation. This unique categorization of ALS opens a variety of treatment options targeting the reestablishment of BCNSB integrity. This review will critically assess the evidence implicating the significant neurovascular components of ALS pathophysiology, while also offering an in-depth discussion regarding the use of stem cells to repair these pathological changes within the neurovascular unit.

The mechanism of action of a novel neuroprotective low molecular weight dextran sulphate: New platform therapy for neurodegenerative diseases like Amyotrophic Lateral Sclerosis

Background: Acute and chronic neurodegenerative diseases represent an immense socioeconomic burden that drives the need for new disease modifying drugs. Common pathogenic mechanisms in these diseases are evident, suggesting that a platform neuroprotective therapy may offer effective treatments. Here we present evidence for the mode of pharmacological action of a novel neuroprotective low molecular weight dextran sulphate drug called ILB^®. The working hypothesis was that ILB^® acts via the activation of heparin-binding growth factors (HBGF).

Methods: Pre-clinical and clinical (healthy people and patients with ALS) in vitro and in vivo studies evaluated the mode of action of ILB^®. In vitro binding studies, functional assays and gene expression analyses were followed by the assessment of the drug effects in an animal model of severe traumatic brain injury (sTBI) using gene expression studies followed by functional analysis. Clinical data, to assess the hypothesized mode of action, are also presented from early phase clinical trials.

Results: ILB^® lengthened APTT time, acted as a competitive inhibitor for HGF-Glypican-3 binding, effected pulse release of heparin-binding growth factors (HBGF) into the circulation and modulated growth factor signaling pathways. Gene expression analysis demonstrated substantial similarities in the functional dysregulation induced by sTBI and various human neurodegenerative conditions and supported a cascading effect of ILB^® on growth factor activation, followed by gene expression changes with profound beneficial effect on molecular and cellular functions affected by these diseases. The transcriptional signature of ILB^® relevant to cell survival, inflammation, glutamate signaling, metabolism and synaptogenesis, are consistent with the activation of neuroprotective growth factors as was the ability of ILB^® to elevate circulating levels of HGF in animal models and humans.

Conclusion: ILB^® releases, redistributes and modulates the bioactivity of HBGF that target disease compromised nervous tissues to initiate a cascade of transcriptional, metabolic and immunological effects that control glutamate toxicity, normalize tissue bioenergetics, and resolve inflammation to improve tissue function. This unique mechanism of action mobilizes and modulates naturally occurring tissue repair mechanisms to restore cellular homeostasis and function. The identified pharmacological impact of ILB^® supports the potential to treat various acute and chronic neurodegenerative disease, including sTBI and ALS.

EST79232 and EST79376, Two Novel Sigma-1 Receptor Ligands, Exert Neuroprotection on Models of Motoneuron Degeneration

Motor neuron diseases (MNDs) include sporadic and hereditary neurological disorders characterized by progressive degeneration of motor neurons (MNs). Sigma-1 receptor (Sig-1R) is a protein enriched in MNs, and mutations on its gene lead to various types of MND. Previous studies have suggested that Sig-1R is a target to prevent MN degeneration. In this study, two novel synthesized Sig-1R ligands, coded EST79232 and EST79376, from the same chemical series, with the same scaffold and similar physicochemical properties but opposite functionality on Sig-1R, were evaluated as neuroprotective compounds to prevent MN degeneration. We used an in vitro model of spinal cord organotypic cultures under chronic excitotoxicity and two in vivo models, the spinal nerve injury and the superoxide dismutase 1 (SOD1)G93A mice, to characterize the effects of these Sig-1R ligands on MN survival and modulation of glial reactivity. The antagonist EST79376 preserved MNs in vitro and after spinal nerve injury but was not able to improve MN death in SOD1G93A mice. In contrast, the agonist EST79232 significantly increased MN survival in the three models of MN degeneration evaluated and had a mild beneficial effect on motor function in SOD1G93A mice. In vivo, Sig-1R ligand EST79232 had a more potent effect on preventing MN degeneration than EST79376. These data further support the interest in Sig-1R as a therapeutic target for neurodegeneration.

Moral obligations in conducting stem cell-based therapy trials for autism spectrum disorder

Unregulated patient treatments and approved clinical trials have been conducted with haematopoietic stem cells and mesenchymal stem cells for children with autism spectrum disorder (ASD). While the former direct-to-consumer practice is usually considered rogue and should be legally constrained, regulated clinical trials could also be ethically questionable. Here, we outline principal objections against these trials as they are currently conducted. Notably, these often lack a clear rationale for how transplanted cells may confer a therapeutic benefit in ASD, and thus, have ill-defined therapeutic outcomes. We posit that ambiguous and unsubstantiated descriptions of outcome from such clinical trials may nonetheless appeal to the lay public as being based on authentic scientific findings. These may further fuel caregivers of patients with ASD to pursue unregulated direct-to-consumer treatments, thus exposing them to unnecessary risks. There is, therefore, a moral obligation on the part of those regulating and conducting clinical trials of stem cell-based therapeutic for ASD minors to incorporate clear therapeutic targets, scientific rigour and reporting accuracy in their work. Any further stem cell-based trials for ASD unsupported by significant preclinical advances and particularly sound scientific hypothesis and aims would be ethically indefensible.

SOD1 in ALS: Taking Stock in Pathogenic Mechanisms and the Role of Glial and Muscle Cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the loss of motor neurons in the brain and spinal cord. While the exact causes of ALS are still unclear, the discovery that familial cases of ALS are related to mutations in the Cu/Zn superoxide dismutase (SOD1), a key antioxidant enzyme protecting cells from the deleterious effects of superoxide radicals, suggested that alterations in SOD1 functionality and/or aberrant SOD1 aggregation strongly contribute to ALS pathogenesis. A new scenario was opened in which, thanks to the generation of SOD1 related models, different mechanisms crucial for ALS progression were identified. These include excitotoxicity, oxidative stress, mitochondrial dysfunctions, and non-cell autonomous toxicity, also implicating altered Ca²⁺ metabolism. While most of the literature considers motor neurons as primary target of SOD1-mediated effects, here we mainly discuss the effects of SOD1 mutations in non-neuronal cells, such as glial and skeletal muscle cells, in ALS. Attention is given to the altered redox balance and Ca²⁺ homeostasis, two processes that are strictly related with each other. We also provide original data obtained in primary myocytes derived from hSOD1(G93A) transgenic mice, showing perturbed expression of Ca²⁺ transporters that may be responsible for altered mitochondrial Ca²⁺ fluxes. ALS-related SOD1 mutants are also responsible for early alterations of fundamental biological processes in skeletal myocytes that may impinge on skeletal muscle functions and the cross-talk between muscle cells and motor neurons during disease progression.

Therapeutic Treatment of Superoxide Dismutase 1 (G93A) Amyotrophic Lateral Sclerosis Model Mice with Medical Ozone Decelerates Trigeminal Motor Neuron Degeneration, Attenuates Microglial Proliferation, and Preserves Monocyte Levels in Mesenteric Lymph Nodes

Amyotrophic lateral sclerosis (ALS) is an incurable and lethal neurodegenerative disease in which progressive motor neuron loss and associated inflammation represent major pathology hallmarks. Both the prevention of neuronal loss and neuro-destructive inflammation are still unmet challenges. Medical ozone, an ozonized oxygen mixture (O₃/O₂), has been shown to elicit profound immunomodulatory effects in peripheral organs, and beneficial effects in the aging brain. We investigated, in a preclinical drug testing approach, the therapeutic potential of a five-day O₃/O₂i.p. treatment regime at the beginning of the symptomatic disease phase in the superoxide dismutase (SOD1^G93A) ALS mouse model. Clinical assessment of SOD1^G93A mice revealed no benefit of medical ozone treatment over sham with respect to gross body weight, motor performance, disease duration, or survival. In the brainstem of end stage SOD1^G93A mice, however, neurodegeneration was found decelerated, and SOD1-related vacuolization was reduced in the motor trigeminal nucleus in the O₃/O₂ treatment group when compared to sham-treated mice. In addition, microglia proliferation was less pronounced in the brainstem, while the hypertrophy of astroglia remained largely unaffected. Finally, monocyte numbers were reduced in the blood, spleen, and mesenteric lymph nodes at postnatal day 60 in SOD1^G93A mice. A further decrease in monocyte numbers seen in mesenteric lymph nodes from sham-treated SOD1^G93A mice at an advanced disease stage, however, was prevented by medical ozone treatment. Collectively, our study revealed a select neuroprotective and possibly anti-inflammatory capacity for medical ozone when applied as a therapeutic agent in SOD1^G93A ALS mice.

Therapeutic Approaches to Amyotrophic Lateral Sclerosis from the Lab to the Clinic

Amyotrophic Lateral Sclerosis (ALS) is a terminal neuro-degenerative disorder that is clinically recognized as a gradual degeneration of the upper and lower motor neurons, with an average duration of 3 to 5 years from initiation of symptoms to death. The mechanisms underlying the pathogenesis and progression of the disease are multifactorial. Therefore, to find effective treatments, it is necessary to understand this heterogeneity underlying the progression of ALS. Recent developments in gene therapy have opened a new avenue to treat this condition, especially for the characterized genetic types. Gene therapy methods have been studied in a variety of pre-clinical settings and clinical trials, and they may be a promising path for developing an effective and safe ALS cure. A growing body of evidence demonstrates abnormalities in energy metabolism at the cellular and whole-body level in animal models and in people living with ALS. The use and incorporation of high-throughput "omics" methods has radically transformed our thought about ALS, strengthening our understanding of the disease's dynamic molecular architecture, differentiating distinct patient subtypes, and creating a reasonable basis for the identification of biomarkers and novel individualised treatments. Future clinical and laboratory trials would also focus on the diverse relationships between metabolism and ALS to address the issue of whether targeting deficient metabolism in ALS is an effective way to change disease progression. In this review, we focus on the detailed pathogenesis of ALS and highlight principal genes, i.e., SOD1, TDP-43, C9orf72, and FUS, targeted therapeutic approaches of ALS. An attempt is made to provide up-to-date information on clinical outcomes, including various biomarkers which are thought to be important players in early ALS detection.

TDP-43 Cytoplasmic Translocation in the Skin Fibroblasts of ALS Patients

Diagnosis of ALS is based on clinical symptoms when motoneuron degeneration is significant. Therefore, new approaches for early diagnosis are needed. We aimed to assess if alterations in appearance and cellular localization of cutaneous TDP-43 may represent a biomarker for ALS. Skin biopsies from 64 subjects were analyzed: 44 ALS patients, 10 healthy controls (HC) and 10 neurological controls (NC) (Parkinson’s disease and multiple sclerosis). TDP-43 immunoreactivity in epidermis and dermis was analyzed, as well as the percentage of cells with TDP-43 cytoplasmic localization. We detected a higher amount of TDP-43 in epidermis (p < 0.001) and in both layers of dermis (p < 0.001), as well as a higher percentage of TDP-43 cytoplasmic positive cells (p < 0.001) in the ALS group compared to HC and NC groups. Dermal cells containing TDP-43 were fibroblasts as identified by co-labeling against vimentin. ROC analyses (AUC 0.867, p < 0.001; CI 95% 0.800–0.935) showed that detection of 24.1% cells with cytoplasmic TDP-43 positivity in the dermis had 85% sensitivity and 80% specificity for detecting ALS. We have identified significantly increased TDP-43 levels in epidermis and in the cytoplasm of dermal cells of ALS patients. Our findings provide support for the use of TDP-43 in skin biopsies as a potential biomarker.

Delivering Bad News in Amyotrophic Lateral Sclerosis: Proposal of Specific Technique ALS ALLOW

Purpose of Review

Physician communication skills are a critical part of care for amyotrophic lateral sclerosis (ALS) patients and caregivers. They shape the development of autonomy and quality of life, and they mitigate emotional trauma. Communication skills are especially critical at 2 different time points in the course of the disease: early when delivering and establishing the diagnosis, and later when clarifying goals of care.

Recent Findings

Several techniques for physician communication of difficult information are available, including SPIKES (Setting up the interview, assessing the patient's Perception, obtaining the patient's Invitation, giving Knowledge and information to the patient, addressing the patient's Emotions with Empathetic responses, and Strategy and Summary), ABCDE (Advance preparation, Build a therapeutic environment/relationship, Communicate well, Deal with patient and family reactions, Encourage and validate emotions), and BREAKS (Background, Rapport, Exploring, Announce, Kindling, Summarize). These emphasize the physician's accountability and responsibility for communicating effectively. Formal training in these techniques is limited, and their applicability specifically to ALS is inexact.

Summary

We propose an ALS-specific technique which we call ALS ALLOW to guide physicians in conducting difficult communications with ALS patients and caregivers to develop their understanding, establish autonomy, set goals, and mitigate emotional trauma. The techniques are useful in discussions both early and late stages in the disease.

Comparative assessment of blood Metal/metalloid levels, clinical heterogeneity, and disease severity in amyotrophic lateral sclerosis patients

Amyotrophic lateral sclerosis is an unremitting neurodegenerative (ND) disease characterized by progressive and fatal loss of motor neuron function. While underlying mechanisms for ALS susceptibility are complex, current understanding suggests that interactions between age, genetic, and environmental factors may be the key. Environmental exposure to metal/metalloids has been implicated in various ND diseases including ALS, Alzheimer's Disease (AD), and Parkinson's Disease (PD). However, most of currently available population-based ALS studies in relation to metal exposure are based on individuals from European ancestry, while East Asian populations, especially cohorts from China, are less well-characterized. This study aims to examine the association between metal/metalloid levels and ALS onset by evaluating blood cadmium (Cd), lead (Pb), Cu, Zn, calcium (Ca), magnesium (Mg), and iron (Fe) levels in controls and sporadic ALS patients from North Western China. We report that Cu and Fe levels are found at higher levels in ALS patients compared to the controls. Spinal and bulbar onset patients show significant difference in Ca levels. Moreover, Cd, Pb, Cu, and Ca levels are positively correlated with high disease severity. Results from this study may provide new insights for understanding not only the role of metal/metalloids in ALS susceptibility, but also progression and forms of onset.

Gene Therapy Overexpressing Neuregulin 1 Type I in Combination With Neuregulin 1 Type III Promotes Functional Improvement in the SOD1G93A ALS Mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting the neuromuscular system for which currently there is no effective therapy. Motoneuron (MN) degeneration involves several complex mechanisms, including surrounding glial cells and skeletal muscle contributions. Neuregulin 1 (NRG1) is a trophic factor present particularly in MNs and neuromuscular junctions. Our previous studies revealed that gene therapy overexpressing the isoform I (NRG1-I) in skeletal muscles as well as overexpressing the isoform III (NRG1-III) directly in the central nervous system are both effective in preserving MNs in the spinal cord of ALS mice, opening novel therapeutic approaches. In this study, we combined administration of both viral vectors overexpressing NRG1-I in skeletal muscles and NRG1-III in spinal cord of the SOD1^G93A mice in order to obtain a synergistic effect. The results showed that the combinatorial gene therapy increased preservation of MNs and of innervated neuromuscular junctions and reduced glial reactivity in the spinal cord of the treated SOD1^G93A mice. Moreover, NRG1 isoforms overexpression improved motor function of hindlimb muscles and delayed the onset of clinical disease. However, this combinatory gene therapy did not produce a synergic effect compared with single therapies, suggesting an overlap between NRG1-I and NRG1-III activated pathways and their beneficial effects.

Cortical hyperexcitability: Diagnostic and pathogenic biomarker of ALS

Cortical hyperexcitability is an early and intrinsic feature of both sporadic and familial forms of amyotrophic lateral sclerosis (ALS).. Importantly, cortical hyperexcitability appears to be associated with motor neuron degeneration, possibly via an anterograde glutamate-mediated excitotoxic process, thereby forming a pathogenic basis for ALS. The presence of cortical hyperexcitability in ALS patients may be readily determined by transcranial magnetic stimulation (TMS), a neurophysiological tool that provides a non-invasive and painless method for assessing cortical function. Utilising the threshold tracking TMS technique, cortical hyperexcitability has been established as a robust diagnostic biomarker that distinguished ALS from mimicking disorders at early stages of the disease process. The present review discusses the pathophysiological and diagnostic utility of cortical hyperexcitability in ALS.

Specific Expression of Glial-Derived Neurotrophic Factor in Muscles as Gene Therapy Strategy for Amyotrophic Lateral Sclerosis

Glial cell line-derived neurotrophic factor (GDNF) is a powerful neuroprotective growth factor. However, systemic or intrathecal administration of GDNF is associated with side effects. Here, we aimed to avoid this by restricting the transgene expression to the skeletal muscle by gene therapy. To specifically target most skeletal muscles in the mouse model of amyotrophic lateral sclerosis (ALS), SOD1G93A transgenic mice were intravenously injected with adeno-associated vectors coding for GDNF under the control of the desmin promoter. Treated and control SOD1G93A mice were evaluated by rotarod and nerve conduction tests from 8 to 20 weeks of age, and then histological and molecular analyses were performed. Muscle-specific GDNF expression delayed the progression of the disease in SOD1G93A female and male mice by preserving the neuromuscular function; increasing the number of innervated neuromuscular junctions, the survival of spinal motoneurons; and reducing glial reactivity in treated SOD1G93A mice. These beneficial actions are attributed to a paracrine protective mechanism from the muscle to the motoneurons by GDNF. Importantly, no adverse secondary effects were detected. These results highlight the potential of muscle GDNF-targeted expression for ALS therapy.

ALS-Like Disorder in Three HIV-Positive Patients: Case Series

There appears to be a relationship between retroviruses such as HIV and the development of an ALS-like syndrome. Few cases have been reported; however, there exists evidence of a higher frequency of motor neuron disease in HIV-infected patients, as well as potential slowing and reversibility of disease course with combination antiretroviral therapy. We conducted a retrospective chart review of patients presenting to the George Washington University ALS Clinic from September 2006 to June 2018 to identify patients with HIV receiving HAART who were subsequently diagnosed with ALS or an ALS-like disorder. Our goals were to describe our patients' disease course and compare them to general characteristics of ALS. We report three cases of HIV-positive individuals, all male, who were subsequently diagnosed with ALS. Each presented with symptoms of limb onset ALS with involvement of upper and lower motor neurons and whose disease originated at the cervical level. All three had been diagnosed with HIV prior to presentation and were presumably compliant with antiretroviral therapy throughout. Our patients demonstrated effective control of their HIV infection. Each experienced relatively slow progression of motor impairment compared to general ALS characteristics. Our study offers a distinct profile of HIV-positive patients compliant with HAART subsequently diagnosed with an ALS-like disorder. Further study should aim to uncover pathophysiological similarities between motor neuron disease both in the presence and absence of retroviral infection and to develop effective medical therapy for each.

Comprehensive in silico analysis and molecular dynamics of the superoxide dismutase 1 (SOD1) variants related to amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) is the most frequent motor neuron disorder, with a significant social and economic burden. ALS remains incurable, and the only drugs approved for its treatments confers a survival benefit of a few months for the patients. Missense mutations in superoxide dismutase 1 (SOD1), a major cytoplasmic antioxidant enzyme, has been associated with ALS development, accounting for 23% of its familial cases and 7% of all sporadic cases. This work aims to characterize in silico the structural and functional effects of SOD1 protein variants. Missense mutations in SOD1 were compiled from the literature and databases. Twelve algorithms were used to predict the functional and stability effects of these mutations. ConSurf was used to estimate the evolutionary conservation of SOD1 amino-acids. GROMACS was used to perform molecular dynamics (MD) simulations of SOD1 wild-type and variants A4V, D90A, H46R, and I113T, which account for approximately half of all ALS-SOD1 cases in the United States, Europe, Japan, and United Kingdom, respectively. 233 missense mutations in SOD1 protein were compiled from the databases and literature consulted. The predictive analyses pointed to an elevated rate of deleterious and destabilizing predictions for the analyzed variants, indicating their harmful effects. The ConSurf analysis suggested that mutations in SOD1 mainly affect conserved and possibly functionally essential amino acids. The MD analyses pointed to flexibility and essential dynamics alterations at the electrostatic and metal-binding loops of variants A4V, D90A, H46R, and I113T that could lead to aberrant interactions triggering toxic protein aggregation. These alterations may have harmful implications for SOD1 and explain their association with ALS. Understanding the effects of SOD1 mutations on protein structure and function facilitates the design of further experiments and provides relevant information on the molecular mechanism of pathology, which may contribute to improvements in existing treatments for ALS.

An overview on amyotrophic lateral sclerosis and cadmium

The present review represents an update about the knowledge of the possible role of Cadmium (Cd) in amyotrophic lateral sclerosis (ALS) initiation and its progression. ALS is a neurodegenerative disease that occurs in adulthood; its etiology is unknown and leads to death within a few years from its appearance. Among the various possible causes that can favor the development of the disease, heavy metals cannot be excluded. Cadmium is a heavy metal that does not play a biological role, but its neurotoxicity is well known. Numerous in vitro studies on cell and animal models confirm the toxicity of the metal on the nervous system, but these data are not accompanied by an epidemiological evidence, and, thus, an unclear correlation between Cd and the onset of the disease can be pointed out. On the other hand, a possible multifactorial and synergic mechanism in which Cd may have a role can explain the ALS onset. More efforts in new clinical, biochemical, and epidemiological studies are necessary to better elucidate the involvement of Cd in this lethal disease.

Bile Acids: A Communication Channel in the Gut-Brain Axis

Bile acids are signalling hormones involved in the regulation of several metabolic pathways. The ability of bile acids to bind and signal through their receptors is modulated by the gut microbiome, since the microbiome contributes to the regulation and synthesis of bile acids as well to their physiochemical properties. From the gut, bacteria have been shown to send signals to the central nervous system via their metabolites, thus affecting the behaviour and brain function of the host organism. In the last years it has become increasingly evident that bile acids affect brain function, during normal physiological and pathological conditions. Although bile acids may be synthesized locally in the brain, the majority of brain bile acids are taken up from the systemic circulation. Since the composition of the brain bile acid pool may be regulated by the action of intestinal bacteria, it is possible that bile acids function as a communication bridge between the gut microbiome and the brain. However, little is known about the molecular mechanisms and the physiological roles of bile acids in the central nervous system. The possibility that bile acids may be a direct link between the intestinal microbiome and the brain is also an understudied subject. Here we review the influence of gut bacteria on the bile acid pool composition and properties, as well as striking evidence showing the role of bile acids as neuroactive molecules.

Sigma-1 and dopamine D2/D3 receptor occupancy of pridopidine in healthy volunteers and patients with Huntington disease: a [18F] fluspidine and [18F] fallypride PET study

PURPOSE

Pridopidine is an investigational drug for Huntington disease (HD). Pridopidine was originally thought to act as a dopamine stabilizer. However, pridopidine shows highest affinity to the sigma-1 receptor (S1R) and enhances neuroprotection via the S1R in preclinical studies. Using [¹⁸F] fluspidine and [¹⁸F] fallypride PET, the purpose of this study was to assess in vivo target engagement/receptor occupancy of pridopidine to the S1R and dopamine D2/D3 receptor (D2/D3R) at clinical relevant doses in healthy volunteers (HVs) and as proof-of-concept in a small number of patients with HD.

METHODS

Using [¹⁸F] fluspidine PET (300 MBq, 0-90 min), 11 male HVs (pridopidine 0.5 to 90 mg; six dose groups) and three male patients with HD (pridopidine 90 mg) were investigated twice, without and 2 h after single dose of pridopidine. Using [¹⁸F] fallypride PET (200 MBq, 0-210 min), four male HVs were studied without and 2 h following pridopidine administration (90 mg). Receptor occupancy was analyzed by the Lassen plot.

RESULTS

S1R occupancy as function of pridopidine dose (or plasma concentration) in HVs could be described by a three-parameter Hill equation with a Hill coefficient larger than one. A high degree of S1R occupancy (87% to 91%) was found throughout the brain at pridopidine doses ranging from 22.5 to 90 mg. S1R occupancy was 43% at 1 mg pridopidine. In contrast, at 90 mg pridopidine, the D2/D3R occupancy was only minimal (~ 3%).

CONCLUSIONS

Our PET findings indicate that at clinically relevant single dose of 90 mg, pridopidine acts as a selective S1R ligand showing near to complete S1R occupancy with negligible occupancy of the D2/D3R. The dose S1R occupancy relationship suggests cooperative binding of pridopidine to the S1R. Our findings provide significant clarification about pridopidine's mechanism of action and support further use of the 45-mg twice-daily dose to achieve full and selective targeting of the S1R in future clinical trials of neurodegenerative disorders. Clinical Trials.gov Identifier: NCT03019289 January 12, 2017; EUDRA-CT-Nr. 2016-001757-41.

Dysregulation of metabolic pathways by carnitine palmitoyl-transferase 1 plays a key role in central nervous system disorders: experimental evidence based on animal models

The etiology of CNS diseases including multiple sclerosis, Parkinson’s disease and amyotrophic lateral sclerosis remains elusive despite decades of research resulting in treatments with only symptomatic effects. In this study, we provide evidence that a metabolic shift from glucose to lipid is a key mechanism in neurodegeneration. We show that, by downregulating the metabolism of lipids through the key molecule carnitine palmitoyl transferase 1 (CPT1), it is possible to reverse or slowdown disease progression in experimental models of autoimmune encephalomyelitis-, SOD1^G93A and rotenone models, mimicking these CNS diseases in humans. The effect was seen both when applying a CPT1 blocker or by using a Cpt1a P479L mutant mouse strain. Furthermore, we show that diet, epigenetics, and microbiota are key elements in this metabolic shift. Finally, we present a systemic model for understanding the complex etiology of neurodegeneration and how different regulatory systems are interconnected through a central metabolic pathway that becomes deregulated under specific conditions.

Sigma 1 receptor as a therapeutic target for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an adult disease causing a progressive loss of upper and lower motoneurons, muscle paralysis and early death. ALS has a poor prognosis of 3-5 years after diagnosis with no effective cure. The aetiopathogenic mechanisms involved include glutamate excitotoxicity, oxidative stress, protein misfolding, mitochondrial alterations, disrupted axonal transport and inflammation. Sigma non-opioid intracellular receptor 1 (sigma 1 receptor) is a protein expressed in motoneurons, mainly found in the endoplasmic reticulum (ER) on the mitochondria-associated ER membrane (MAM) or in close contact with cholinergic postsynaptic sites. MAMs are sites that allow the assembly of several complexes implicated in essential survival cell functions. The sigma 1 receptor modulates essential mechanisms for motoneuron survival including excitotoxicity, calcium homeostasis, ER stress and mitochondrial dysfunction. This review updates sigma 1 receptor mechanisms and its alterations in ALS, focusing on MAM modulation, which may constitute a novel target for therapeutic strategies. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc.

Therapeutic Role of Neuregulin 1 Type III in SOD1-Linked Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating motoneuron (Mn) disease without effective cure currently available. Death of MNs in ALS is preceded by failure of neuromuscular junctions and axonal retraction. Neuregulin 1 (NRG1) is a neurotrophic factor highly expressed in MNs and neuromuscular junctions that support axonal and neuromuscular development and maintenance. NRG1 and its ErbB receptors are involved in ALS. Reduced NRG1 expression has been found in ALS patients and in the ALS SOD1G93A mouse model; however, the expression of the isoforms of NRG1 and its receptors is still controversial. Due to the reduced levels of NRG1 type III (NRG1-III) in the spinal cord of ALS patients, we used gene therapy based on intrathecal administration of adeno-associated virus to overexpress NRG1-III in SOD1G93A mice. The mice were evaluated from 9 to 16 weeks of age by electrophysiology and rotarod tests. At 16 weeks, samples were harvested for histological and molecular analyses. Our results indicate that overexpression of NRG1-III is able to preserve neuromuscular function of the hindlimbs, improve locomotor performance, increase the number of surviving MNs, and reduce glial reactivity in the treated female SOD1G93A mice. Furthermore, the NRG1-III/ErbB4 axis appears to regulate MN excitability by modulating the chloride transporter KCC2 and reduces the expression of the MN vulnerability marker MMP-9. However, NRG1-III did not have a significant effect on male mice, indicating relevant sex differences. These findings indicate that increasing NRG1-III at the spinal cord is a promising approach for promoting MN protection and functional improvement in ALS.

Interaction Between Mitochondrial DNA Variants and Mitochondria/Endoplasmic Reticulum Contact Sites: A Perspective Review

Mitochondria contain their own genome, mitochondrial DNA (mtDNA), essential to support their fundamental intracellular role in ATP production and other key metabolic and homeostatic pathways. Mitochondria are highly dynamic organelles that communicate with all the other cellular compartments, through sites of high physical proximity. Among all, their crosstalk with the endoplasmic reticulum (ER) appears particularly important as its derangement is tightly implicated with several human disorders. Population-specific mtDNA variants clustered in defining the haplogroups have been shown to exacerbate or mitigate these pathological conditions. The exact mechanisms of the mtDNA background-modifying effect are not completely clear and a possible explanation is the outcome of mitochondrial efficiency on retrograde signaling to the nucleus. However, the possibility that different haplogroups shape the proximity and crosstalk between mitochondria and the ER has never been proposed neither investigated. In this study, we pose and discuss this question and provide preliminary data to answer it. Besides, we also address the possibility that single, disease-causing mtDNA point mutations may act also by reshaping organelle communication. Overall, this perspective review provides a theoretical platform for future studies on the interaction between mtDNA variants and organelle contact sites.

Why do anti-inflammatory signals of bone marrow-derived stromal cells improve neurodegenerative conditions where anti-inflammatory drugs fail?

Neurodegenerative disorders share the final degenerative pathway, the inflammation-induced apoptosis and/or necrosis, irrespective of their etiology, be it of acute and chronic traumatic, vascular and idiopathic origin. Although disease-modifying strategies are an unmet need in these disorders, lately, (pre)clinical studies suggested favorable effects after an intervention with bone marrow-derived stromal cells (bm-SC). Recent interventions with intrathecal transplantation of these cells in preclinical rodent models improved the functional outcome and reduced the inflammation, but not anti-inflammatory drugs. The benefit of bm-SCs was demonstrated in rats with an acute (traumatic spinal cord injury, tSCI) and in mice with a chronic [amyotrophic lateral sclerosis (ALS)-like FUS 1-358 or SOD1-G93-A mutation] neurodegenerative process. Bm-SCs, were found to modify underlying disease processes, to reduce final clinical SCI-related outcome, and to slow down ALS-like clinical progression. After double-blind interventions with bm-SC transplantations, Vehicle (placebo), and (non)steroidal anti-inflammatory drugs (Methylprednisolone, Riluzole, Celecoxib), clinical, histological and histochemical findings, serum/spinal cytokines, markers for spinal microglial activation inclusive, evidenced the cell-to-cell action of bm-SCs in both otherwise healthy and immune-deficient tSCI-rats, as well as wild-type and FUS/SOD1-transgenic ALS-like mice. The multi-pathway hypothesis of the cell-to-cell action of bmSCs, presumably using extracellular vesicles (EVs) as carriers of messages in the form of RNAs, DNA, proteins, and lipids rather than influencing a single inflammatory pathway, could be justified by the reported differences of cytokines and other chemokines in the serum and spinal tissue. The mode of action of bm-SCs is hypothesized to be associated with its dedicated adjustment of the pro-apoptotic glycogen synthase kinase-3β level towards an anti-apoptotic level whereas their multi-pathway hypothesis seems to be confirmed by the decreased levels of the pro-inflammatory interleukin (IL)-1β and tumor necrosis factor (TNF) as well as the level of the marker of activated microglia, ionized calcium binding adapter (Iba)-1 level.

Combined intramuscular and intraspinal transplant of bone marrow cells improves neuromuscular function in the SOD1G93A mice

Background

The simultaneous contribution of several etiopathogenic disturbances makes amyotrophic lateral sclerosis (ALS) a fatal and challenging disease. Here, we studied two different cell therapy protocols to protect both central and peripheral nervous system in a murine model of ALS.

Methods

Since ALS begins with a distal axonopathy, in a first assay, we performed injection of bone marrow cells into two hindlimb muscles of transgenic SOD1^G93A mice. In a second study, we combined intramuscular and intraspinal injection of bone marrow cells. Fluorescence-activated cell sorting was used to assess the survival of the transplanted cells into the injected tissues. The mice were assessed from 8 to 16 weeks of age by means of locomotion and electrophysiological tests. After follow-up, the spinal cord was processed for analysis of motoneuron survival and glial cell reactivity.

Results

We found that, after intramuscular injection, bone marrow cells were able to engraft within the muscle. However, bone marrow cell intramuscular injection failed to promote a general therapeutic effect. In the second approach, we found that bone marrow cells had limited survival in the spinal cord, but this strategy significantly improved motor outcomes. Moreover, we also found that the dual cell therapy tended to preserve spinal motoneurons at late stages of the disease and to reduce microgliosis, although this did not prolong mice survival.

Conclusion

Overall, our findings suggest that targeting more than one affected area of the motor system at once with bone marrow cell therapy results in a valuable therapeutic intervention for ALS.

Gene therapy for overexpressing Neuregulin 1 type I in skeletal muscles promotes functional improvement in the SOD1G93A ALS mice

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motoneurons (MNs), with no effective treatment currently available. The molecular mechanisms that are involved in MN death are complex and not fully understood, with partial contributions of surrounding glial cells and skeletal muscle to the disease. Neuregulin 1 (NRG1) is a trophic factor highly expressed in MNs and neuromuscular junctions. Recent studies have suggested a crucial role of the isoform I (NRG1-I) in the collateral reinnervation process in skeletal muscle, and NRG1-III in the preservation of MNs in the spinal cord, opening a window for developing novel therapies for neuromuscular diseases like ALS. In this study, we overexpressed NRG1-I widely in the skeletal muscles of the SOD1^G93A transgenic mouse. The results show that NRG1 gene therapy activated the survival pathways in muscle and spinal cord, increasing the number of surviving MNs and neuromuscular junctions and reducing the astroglial reactivity in the spinal cord of the treated SOD1^G93A mice. Furthermore, NRG1-I overexpression preserved motor function and delayed the onset of clinical disease. In summary, our data indicates that NRG1 plays an important role on MN survival and muscle innervation in ALS, and that viral-mediated overexpression of NRG1 isoforms may be considered as a promising approach for ALS treatment.

New insights into Wnt signaling alterations in amyotrophic lateral sclerosis: a potential therapeutic target?

Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder characterized by upper and lower motor neuron degeneration, which leads to progressive paralysis of skeletal muscles and, ultimately, respiratory failure between 2–5 years after symptom onset. Unfortunately, currently accepted treatments for amyotrophic lateral sclerosis are extremely scarce and only provide modest benefit. As a consequence, a great effort is being done by the scientific community in order to achieve a better understanding of the different molecular and cellular processes that influence the progression and/or outcome of this neuropathological condition and, therefore, unravel new potential targets for therapeutic intervention. Interestingly, a growing number of experimental evidences have recently shown that, besides its well-known physiological roles in the developing and adult central nervous system, the Wnt family of proteins is involved in different neuropathological conditions, including amyotrophic lateral sclerosis. These proteins are able to modulate, at least, three different signaling pathways, usually known as canonical (β-catenin dependent) and non-canonical (β-catenin independent) signaling pathways. In the present review, we aim to provide a general overview of the current knowledge that supports the relationship between the Wnt family of proteins and its associated signaling pathways and amyotrophic lateral sclerosis pathology, as well as their possible mechanisms of action. Altogether, the currently available knowledge suggests that Wnt signaling modulation might be a promising therapeutic approach to ameliorate the histopathological and functional deficits associated to amyotrophic lateral sclerosis, and thus improve the progression and outcome of this neuropathology.

Spinal Cord Metabolic Signatures in Models of Fast- and Slow-Progressing SOD1G93A Amyotrophic Lateral Sclerosis

The rate of disease progression in amyotrophic lateral sclerosis (ALS) is highly variable, even between patients with the same genetic mutations. Metabolic alterations may affect disease course variability in ALS patients, but challenges in identifying the preclinical and early phases of the disease limit our understanding of molecular mechanisms underlying differences in the rate of disease progression. We examined effects of SOD1^G93A on thoracic and lumbar spinal cord metabolites in two mouse ALS models with different rates of disease progression: the transgenic SOD1^G93A-C57BL/6JOlaHsd (C57-G93A, slow progression) and transgenic SOD1^G93A-129SvHsd (129S-G93A, fast progression) strains. Samples from three timepoints (presymptomatic, disease onset, and late stage disease) were analyzed using Gas Chromatography-Mass Spectrometry metabolomics. Tissue metabolome differences in the lumbar spinal cord were driven primarily by mouse genetic background, although larger responses were observed in metabolic trajectories after the onset of symptoms. The significantly affected lumbar spinal cord metabolites were involved in energy and lipid metabolism. In the thoracic spinal cord, metabolic differences related to genetic background, background-SOD1 genotype interactions, and longitudinal SOD1^G93A effects. The largest responses in thoracic spinal cord metabolic trajectories related to SOD1^G93A effects before onset of visible symptoms. More metabolites were significantly affected in the thoracic segment, which were involved in energy homeostasis, neurotransmitter synthesis and utilization, and the oxidative stress response. We find evidence that initial metabolic alterations in SOD1^G93A mice confer disadvantages for maintaining neuronal viability under ALS-related stressors, with slow-progressing C57-G93A mice potentially having more favorable spinal cord bioenergetic profiles than 129S-G93A. These genetic background-associated metabolic differences together with the different early metabolic responses underscore the need to better characterize the impact of germline genetic variation on cellular responses to ALS gene mutations both before and after the onset of symptoms in order to understand their impact on disease development.

Regulatory T cells for amyotrophic lateral sclerosis/motor neuron disease: A clinical and preclinical systematic review

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by neuronal degeneration and inflammation in the nerves. The role of the immune system has been concentrated by researchers in the etiopathogenesis of the disease. Given the inhibitory roles of regulatory T cells (Tregs), it is expected that increasing or activating their populations in patients with ALS can have significant therapeutic effects. Here we searched databases, including CENTRAL, MEDLINE, CINAHL Plus, clinicaltrials.gov, and ICTRP for randomized clinical trials (RCTs) and non-RCTs until March 2019. For preclinical studies, we searched PubMed, Scopus, and Google Scholar up to June 2019. We also included preclinical studies, due to the lack of clinical information available, which used Tregs (or directly targeting them) for treating mice models of ALS. We identified 29 records (CENTRAL 7, MEDLINE 4, CINAHL Plus 8, and clinicaltrials.gov 10) and removed 10 duplicated publications. After screening, we identified one RCT which had been published as an abstract, three non-RCTs, and four ongoing studies. We also identified 551 records (PubMed 446, Google Scholar 68, and Scopus 37) for preclinical studies and performed a meta-analysis. Finally, we found three papers that matched our inclusion criteria for preclinical studies. Results indicated the effectiveness of the application of Tregs in the treatment of ALS. Our meta-analysis on preclinical studies revealed that Tregs significantly prolonged survival in mice models of ALS. Overall, our analysis testified that exertion of Tregs in the treatment of ALS is a promising approach, that notwithstanding, requires further evaluations.

Articulation contact pressures scaled to the physiologic range of the tongue in amyotrophic lateral sclerosis: A pilot study

OBJECTIVE

The aim of this study was to compare the percentage of the maximum isometric lingual strength range at which lingual-alveolar consonants are produced (%P_max) by people with amyotrophic lateral sclerosis (PALS) compared to people without the disease measured at study entry, and then 3 and 6 months later.

DESIGN

Prospective cohort comparison study over time.

METHODS

Ten people with ALS and nine without produced the consonants /t, d, s, z, l, n/ in real words within sentences as the articulatory contact pressure (ACP) between the tongue tip and palate was sensed by a miniature transducer. Maximum isometric tongue pressing values also were obtained to allow calculation of %P_max. Data were analyzed to compare PALS with bulbar symptoms, PALS with spinal-only symptoms, and people without ALS.

RESULTS

%P_max did not differ between any of the three participant groups at any of the three measurement times. Maximum isometric pressure did decrease significantly in both ALS groups when comparing baseline to 3- and 6-months later. Maximum pressures remained stable for the non-ALS group at the three measurement times.

CONCLUSION

The results suggest that speech motor activity of the tongue in people with ALS may be scaled relative to their overall tongue strength, such that the %P_max does not change as the tongue gets progressively weaker.

The Biosynthesis, Signaling, and Neurological Functions of Bile Acids

Bile acids (BA) are amphipathic steroid acids synthesized from cholesterol in the liver. They act as detergents to expedite the digestion and absorption of dietary lipids and lipophilic vitamins. BA are also considered to be signaling molecules, being ligands of nuclear and cell-surface receptors, including farnesoid X receptor and Takeda G-protein receptor 5. Moreover, BA also activate ion channels, including the bile acid-sensitive ion channel and epithelial Na⁺ channel. BA regulate glucose and lipid metabolism by activating these receptors in peripheral tissues, such as the liver and brown and white adipose tissue. Recently, 20 different BA have been identified in the central nervous system. Furthermore, BA affect the function of neurotransmitter receptors, such as the muscarinic acetylcholine receptor and γ-aminobutyric acid receptor. BA are also known to be protective against neurodegeneration. Here, we review recent findings regarding the biosynthesis, signaling, and neurological functions of BA.

SOD1 in amyotrophic lateral sclerosis development - in silico analysis and molecular dynamics of A4F and A4V variants

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is characterized by the selective loss of motor neurons. Approximately 5% to 10% of patients with ALS have a family history of the disease, and approximately 20% of familial amyotrophic lateral sclerosis (fALS) cases are associated with mutations in Cu/Zn superoxide dismutase (SOD1). In this study, we evaluated the structural and functional effects of human A4F and A4V SOD1 protein mutations. We performed an in silico analysis using prediction algorithms of nonsynonymous single-nucleotide polymorphisms (nsSNPs) associated with the fALS development. Our structural conservation results show that the mutations analyzed (A4V and A4F) were in a highly conserved region. Molecular dynamics simulations using the Linux GROMACS package revealed how these mutations affect protein structure, protein stability, and aggregation. These results suggest that there might be an effect on the SOD1 function. Understanding the molecular basis of disease provides new insights useful for rational drug design and advancing our understanding of the ALS development.

ROCK inhibition improves axonal regeneration in a preclinical model of amyotrophic lateral sclerosis

Alteration of the RhoA/ROCK (Rho kinase) pathway has been shown to be neuroprotective in SOD1^G93A mice, the most commonly used animal model of ALS. Since previous studies indicate that, apart from neuroprotection, ROCK inhibitor Y-27632 can also accelerate regeneration of motor axons, we here assessed the regenerative capability of axons in SOD1^G93A mice with and without treatment with Y-27632. Regeneration of axons was examined after sciatic nerve crush in pre- and symptomatic SOD1^G93A mice. Proregenerative effects of Y-27632 were studied during the disease course in the SOD1^G93A mouse model. In symptomatic SOD1^G93A mice, axonal regeneration was markedly reduced compared to presymptomatic SOD1^G93A mice and wild types. Treatment with Y-27632 improved functional and morphological measures of motor axons after sciatic crush in all tested conditions. Y-27632 treatment did not increase the lifespan of symptomatic SOD1^G93A mice, but did improve axonal (re)innervation of neuromuscular junctions. Our study provides proof of concept that axonal regeneration of motor neurons harboring SOD1^G93A is impaired, but amenable for pharmacological interventions aiming to accelerate axonal regeneration. Given the lack of treatments for ALS, approaches to improve axonal regeneration, including by inhibiting ROCK, should be further explored.

Artificial MicroRNAs Targeting C9orf72 Can Reduce Accumulation of Intra-nuclear Transcripts in ALS and FTD Patients

The most common pathogenic mutation in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is an intronic GGGGCC (G4C2) repeat in the chromosome 9 open reading frame 72 (C9orf72) gene. Cellular toxicity due to RNA foci and dipeptide repeat (DPR) proteins produced by the sense and antisense repeat-containing transcripts is thought to underlie the pathogenesis of both diseases. RNA sequencing (RNA-seq) data of C9orf72-ALS patients and controls were analyzed to better understand the sequence conservation of C9orf72 in patients. MicroRNAs were developed in conserved regions to silence C9orf72 (miC), and the feasibility of different silencing approaches was demonstrated in reporter overexpression systems. In addition, we demonstrated the feasibility of a bidirectional targeting approach by expressing two concatenated miC hairpins. The efficacy of miC was confirmed by the reduction of endogenously expressed C9orf72 mRNA, in both nucleus and cytoplasm, and an ∼50% reduction of nuclear RNA foci in (G4C2)44-expressing cells. Ultimately, two miC candidates were incorporated in adeno-associated virus vector serotype 5 (AAV5), and silencing of C9orf72 was demonstrated in HEK293T cells and induced pluripotent stem cell (iPSC)-derived neurons. These data support the feasibility of microRNA (miRNA)-based and AAV-delivered gene therapy that could alleviate the gain of toxicity seen in ALS and FTD patients.

Tetanus toxin C-fragment protects against excitotoxic spinal motoneuron degeneration in vivo

The tetanus toxin C-fragment is a non-toxic peptide that can be transported from peripheral axons into spinal motoneurons. In in vitro experiments it has been shown that this peptide activates signaling pathways associated with Trk receptors, leading to cellular survival. Because motoneuron degeneration is the main pathological hallmark in motoneuron diseases, and excitotoxicity is an important mechanism of neuronal death in this type of disorders, in this work we tested whether the tetanus toxin C-fragment is able to protect MN in the spinal cord in vivo. For this purpose, we administered the peptide to rats subjected to excitotoxic motoneuron degeneration induced by the chronic infusion of AMPA in the rat lumbar spinal cord, a well-established model developed in our laboratory. Because the intraspinal infusion of the fragment was only weakly effective, whereas the i.m. administration was remarkably neuroprotective, and because the i.m. injection of an inhibitor of Trk receptors diminished the protection, we conclude that such effects require a retrograde signaling from the neuromuscular junction to the spinal motoneurons. The protection after a simple peripheral route of administration of the fragment suggests a potential therapeutic use of this peptide to target spinal MNs exposed to excitotoxic conditions in vivo.

Associative Increases in Amyotrophic Lateral Sclerosis Survival Duration With Non-invasive Ventilation Initiation and Usage Protocols

Objective: It is hypothesized earlier non-invasive (NIV) ventilation benefits Amyotrophic Lateral Sclerosis (ALS) patients. NIV typically consists of the removable bi-level positive airway pressure (Bi-PAP) for adjunctive respiratory support and/or the cough assist intervention for secretion clearance. Historical international standards and current USA insurance standards often delay NIV until percent predicted forced vital capacity (FVC %predict) is <50. We identify the optimal point for Bi-PAP initiation and the synergistic benefit of daily Bi-PAP and cough assist on associative increases in survival duration.

Methods: Study population consisted of a retrospective ALS cohort (Emory University, Atlanta, GA, USA). Primary analysis included 474 patients (403 Bi-PAP users, 71 non-users). Survival duration (time elapsed from baseline onset until death) is compared on the basis of Bi-PAP initiation threshold (FVC %predict); daily Bi-PAP usage protocol (hours/day); daily cough assist usage (users or non-users); ALS onset type; ALSFRS-R score; and time elapsed from baseline onset until Bi-PAP initiation, using Kruskal-Wallis one-way analysis of variance and Kaplan Meier.

Results: Bi-PAP users' median survival (21.03 months, IQR = 23.97, N = 403) is significantly longer (p < 0.001) than non-users (13.84 months, IQR = 11.97, N = 71). Survival consistently increases (p < 0.01) with FVC %predict Bi-PAP initiation threshold: <50% (20.3 months); ≥50% (23.60 months); ≥80% (25.36 months). Bi-PAP usage >8 hours/day (23.20 months) or any daily Bi-PAP usage with cough assist (25.73 months) significantly (p < 0.001) extends survival compared to Bi-PAP alone (15.0 months). Cough assist without Bi-PAP has insignificant impact (14.17 months) over no intervention (13.68 months). Except for bulbar onset Bi-PAP users, higher ALSFRS-R total scores at Bi-PAP initiation significantly correlate with higher initiation FVC %predict and longer survival duration. Time elapsed since ALS onset is not a good predictor of when NIV should be initiated.

Conclusions: The “optimized” NIV protocol (Bi-PAP initiation while FVC %predict ≥80, Bi-PAP usage >8 h/day, daily cough assist usage) has a 30. 8 month survival median, which is double that of a “standard” NIV protocol (initiation FVC %predict <50, usage >4 h/day, no cough assist). Earlier access to Bi-PAP and cough assist, prior to precipitous respiratory decline, is needed to maximize NIV synergy and associative survival benefit.

The biomedical challenge of neurodegenerative disorders: an opportunity for cannabinoid-based therapies to improve on the poor current therapeutic outcomes

At the beginning of the 21st century, the therapeutic management of neurodegenerative disorders remains a major biomedical challenge, particularly given the worldwide ageing of the population over the past 50 years that is expected to continue in the forthcoming years. This review will focus on the promise of cannabinoid-based therapies to address this challenge. This promise is based on the broad neuroprotective profile of cannabinoids, which may cooperate to combat excitotoxicity, oxidative stress, glia-driven inflammation and protein aggregation. Such effects may be produced by the activity of cannabinoids through their canonical targets (e.g. cannabinoid receptors and endocannabinoid enzymes) and also via non-canonical elements and activities in distinct cell types critical for cell survival or neuronal replacement (e.g. neurons, glia and neural precursor cells). Ultimately, the therapeutic events driven by endocannabinoid signalling reflect the activity of an endogenous system that regulates the preservation, rescue, repair and replacement of neurons and glia. LINKED ARTICLES: This article is part of a themed section on 8^th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

Spatial Assessment of the Association between Long-Term Exposure to Environmental Factors and the Occurrence of Amyotrophic Lateral Sclerosis in Catalonia, Spain: A Population-Based Nested Case-Control Study

BACKGROUND

It is believed that an interaction between genetic and non-genetic factors may be involved in the development of amyotrophic lateral sclerosis (ALS). With the exception of exposure to agricultural chemicals like pesticides, evidence of an association between environmental risk factors and ALS is inconsistent. Our objective here was to investigate the association between long-term exposure to environmental factors and the occurrence of ALS in Catalonia, Spain, and to provide evidence that spatial clusters of ALS related to these environmental factors exist.

METHODS

We carried out a nested case-control study constructed from a retrospective population-based cohort, covering the entire region. Environmental variables were the explanatory variables of interest. We controlled for both observed and unobserved confounders.

RESULTS

We have found some spatial clusters of ALS. The results from the multivariate model suggest that these clusters could be related to some of the environmental variables, in particular agricultural chemicals. In addition, in high-risk clusters, besides corresponding to agricultural areas, key road infrastructures with a high density of traffic are also located.

CONCLUSION

Our results indicate that some environmental factors, in particular those associated with exposure to pesticides and air pollutants as a result of urban traffic, could be associated with the occurrence of ALS.

Patient-Derived iPSCs and iNs-Shedding New Light on the Cellular Etiology of Neurodegenerative Diseases

Induced pluripotent stem cells (iPSCs) and induced neuronal (iN) cells are very much touted in terms of their potential promises in therapeutics. However, from a more fundamental perspective, iPSCs and iNs are invaluable tools for the postnatal generation of specific diseased cell types from patients, which may offer insights into disease etiology that are otherwise unobtainable with available animal or human proxies. There are two good recent examples of such important insights with diseased neurons derived via either the iPSC or iN approaches. In one, induced motor neurons (iMNs) derived from iPSCs of Amyotrophic lateral sclerosis/Frontotemporal dementia (ALS/FTD) patients with a C9orf72 repeat expansion revealed a haploinsufficiency of protein function resulting from the intronic expansion and deficiencies in motor neuron vesicular trafficking and lysosomal biogenesis that were not previously obvious in knockout mouse models. In another, striatal medium spinal neurons (MSNs) derived directly from fibroblasts of Huntington’s disease (HD) patients recapitulated age-associated disease signatures of mutant Huntingtin (mHTT) aggregation and neurodegeneration that were not prominent in neurons differentiated indirectly via iPSCs from HD patients. These results attest to the tremendous potential for pathologically accurate and mechanistically revealing disease modelling with advances in the derivation of iPSCs and iNs.

Trace elements in ALS patients and their relationships with clinical severity

An exploratory study of trace elements in ALS and their relationships with clinical severity was detected. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that causes irreversible damage in humans, with the consequent loss of function of motoneurons (MNs), with a prognosis up to 5 years after diagnosis. Except to genetic rare cases it is not known the etiology of the disorder. Aim of our research is to investigate the possible role of heavy metals in the severity of the disease. In this study, by the use of plasma mass (ICP-MS), we have analyzed the content of essential and heavy metals such: Pb, Cd, Al, Hg, Mn, Fe, Cu, Zn, Se, Mg, and Ca, in blood, urine and hair of ALS patients and controls; moreover we divided the patients in two groups for disease severity and analyzed the difference among the groups, in order to study a possible involvement of metals in the severity of the damage. Our results suggest a protective role of Selenium, involved in protective antioxidant mechanisms, and a risk factor in the case of presence of Lead in blood. The levels of the other metals are not easy to interpret, because these may be due to life style and for essential metals a consequence of the disease condition, not a cause.

Painless motor radiculopathy of the cervical spine: clinical and radiological characteristics and long-term outcomes after operative decompression

OBJECTIVE Various neurological diseases are known to cause progressive painless paresis of the upper limbs. In this study the authors describe the previously unspecified syndrome of compression-induced painless cervical radiculopathy with predominant motor deficit and muscular atrophy, and highlight the clinical and radiological characteristics and outcomes after surgery for this rare syndrome, along with its neurological differential diagnoses. METHODS Medical records of 788 patients undergoing surgical decompression due to degenerative cervical spine diseases between 2005 and 2014 were assessed. Among those patients, 31 (3.9%, male to female ratio 4.8 to 1, mean age 60 years) presented with painless compressive cervical motor radiculopathy due to neuroforaminal stenosis without signs of myelopathy; long-term evaluation was available in 23 patients with 49 symptomatic foraminal stenoses. Clinical, imaging, and operative findings as well as the long-term course of paresis and quality of life were analyzed. RESULTS Presenting symptoms (mean duration 13.3 months) included a defining progressive flaccid radicular paresis (median grade 3/5) without any history of radiating pain (100%) and a concomitant muscular atrophy (78%); 83% of the patients were smokers and 17% patients had diabetes. Imaging revealed a predominantly anterior nerve root compression at the neuroforaminal entrance in 98% of stenoses. Thirty stenoses (11 patients) were initially decompressed via an anterior surgical approach and 19 stenoses (12 patients) via a posterior surgical approach. Overall reoperation rate due to new or recurrent stenoses was 22%, with time to reoperation shorter in smokers (p = 0.033). Independently of the surgical procedure chosen, long-term follow-up (mean 3.9 years) revealed a stable or improved paresis in 87% of the patients (median grade 4/5) and an excellent general performance and quality of life. CONCLUSIONS Painless cervical motor radiculopathy predominantly occurs due to focal compression of the anterior nerve root at the neuroforaminal entrance. Surgical decompression is effective in stabilizing or improving motor function with a resulting favorable long-term outcome.

RNS60 exerts therapeutic effects in the SOD1 ALS mouse model through protective glia and peripheral nerve rescue

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects the motor neuromuscular system leading to complete paralysis and premature death. The multifactorial nature of ALS that involves both cell-autonomous and non-cell-autonomous processes contributes to the lack of effective therapies, usually targeted to a single pathogenic mechanism. RNS60, an experimental drug containing oxygenated nanobubbles generated by modified Taylor-Couette-Poiseuille flow with elevated oxygen pressure, has shown anti-inflammatory and neuroprotective properties in different experimental paradigms. Since RNS60 interferes with multiple cellular mechanisms known to be involved in ALS pathology, we evaluated its effect in in vitro and in vivo models of ALS.

METHODS

Co-cultures of primary microglia/spinal neurons exposed to LPS and astrocytes/spinal neurons from SOD1^G93A mice were used to examine the effect of RNS60 or normal saline (NS) on the selective motor neuron degeneration. Transgenic SOD1^G93A mice were treated with RNS60 or NS (300 μl/mouse intraperitoneally every other day) starting at the disease onset and examined for disease progression as well as pathological and biochemical alterations.

RESULTS

RNS60 protected motor neurons in in vitro paradigms and slowed the disease progression of C57BL/6-SOD1^G93A mice through a significant protection of spinal motor neurons and neuromuscular junctions. This was mediated by the (i) activation of an antioxidant response and generation of an anti-inflammatory environment in the spinal cord; (ii) activation of the PI3K-Akt pro-survival pathway in the spinal cord and sciatic nerves; (iii) reduced demyelination of the sciatic nerves; and (iv) elevation of peripheral CD4+/Foxp3+ T regulatory cell numbers. RNS60 did not show the same effects in 129Sv-SOD1^G93A mice, which are unable to activate a protective immune response.

CONCLUSION

RNS60 demonstrated significant therapeutic efficacy in C57BL/6-SOD1^G93A mice by virtue of its effects on multiple disease mechanisms in motor neurons, glial cells, and peripheral immune cells. These findings, together with the excellent clinical safety profile, make RNS60 a promising candidate for ALS therapy and support further studies to unravel its molecular mechanism of action. In addition, the differences in efficacy of RNS60 in SOD1^G93A mice of different strains may be relevant for identifying potential markers to predict efficacy in clinical trials.