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![Gene therapy mechanism of action. Schematic representation of possible gene therapy approaches in ALS treatment. All of these approaches
can be effective by intra-thecal, intracerebroventricular or peripheral injection of AAV or lentivirus targeting motor neurons or glial cells. a Antisense
olinucleotide (ASO) are short synthetic oligonucleotides (15-25 nucleotides) which bind to targeted mRNA. ASO reduces the expression of a specific
protein by two main mechanisms. ASO induces the mRNA degradation by endogenous RNase H or blocks the mRNA translation. This is a potential
therapeutic avenue in ALS by reducing the protein level of TDP-43, SOD1 of FUS protein level or by targeting of C9orf72 RNA foci. b SiRNAs are
double-stranded RNAs which operated through RNA interference pathway. After strand unwinding, one siRNA strand binds argonaute proteins as part
of the RNA-induced silencing complex (RISC) and is recruited to a target mRNA which is then cleaved. c Antibodies are another potential therapeutics
avenue in ALS [111]. Antibodies can target misfolded proteins and reduce the amount of toxic aggregates. It is suggested that they can reduces the
disease propagation between cells. They can also be exploited to block the pathological interaction between proteins by binding to the specific
interaction sites. d Gene delivery is another potential therapeutic avenue for loss-of-function mutations. Virus can provide a functional replacement
of a missing gene by mRNA or cDNA delivery. This approach was particularly tested in spinal muscular atrophy and revealed great outcomes but is not
yet extensively tested in ALS [231]](publication/305282616/figure/fig4/AS:386051815297024@1469053333109/Gene-therapy-mechanism-of-action-Schematic-representation-of-possible-gene-therapy.png)
Gene therapy mechanism of action. Schematic representation of possible gene therapy approaches in ALS treatment. All of these approaches can be effective by intra-thecal, intracerebroventricular or peripheral injection of AAV or lentivirus targeting motor neurons or glial cells. a Antisense olinucleotide (ASO) are short synthetic oligonucleotides (15-25 nucleotides) which bind to targeted mRNA. ASO reduces the expression of a specific protein by two main mechanisms. ASO induces the mRNA degradation by endogenous RNase H or blocks the mRNA translation. This is a potential therapeutic avenue in ALS by reducing the protein level of TDP-43, SOD1 of FUS protein level or by targeting of C9orf72 RNA foci. b SiRNAs are double-stranded RNAs which operated through RNA interference pathway. After strand unwinding, one siRNA strand binds argonaute proteins as part of the RNA-induced silencing complex (RISC) and is recruited to a target mRNA which is then cleaved. c Antibodies are another potential therapeutics avenue in ALS [111]. Antibodies can target misfolded proteins and reduce the amount of toxic aggregates. It is suggested that they can reduces the disease propagation between cells. They can also be exploited to block the pathological interaction between proteins by binding to the specific interaction sites. d Gene delivery is another potential therapeutic avenue for loss-of-function mutations. Virus can provide a functional replacement of a missing gene by mRNA or cDNA delivery. This approach was particularly tested in spinal muscular atrophy and revealed great outcomes but is not yet extensively tested in ALS [231]
Source publication
Amyotrophic Lateral Sclerosis (ALS) is the most frequent motor neuron disease in adults. Classical ALS is characterized by the death of upper and lower motor neurons leading to progressive paralysis. Approximately 10 % of ALS patients have familial form of the disease. Numerous different gene mutations have been found in familial cases of ALS, such...
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Mutations to the gene encoding superoxide dismutase-1 (SOD1) were the first genetic elements discovered that cause motor neuron disease (MND). These mutations result in compromised SOD1 dimer stability, with one of the severest and most common mutations Ala4Val (A4V) displaying a propensity to monomerise and aggregate leading to neuronal death. We...
Aggregation of Cu-Zn superoxide dismutase (SOD1) is implicated in the motor neuron disease, ALS. Although more than 140 disease mutations of SOD1 are available, their stability or aggregation behaviors in membrane environment are not correlated with disease pathophysiology. Here, we use multiple mutational variants of SOD1 to show that the absence...
Citations
... The importance of identifying biomarkers to validate new treatments is evident. In this study, we study the SOD1 G93A mouse, a well-known murine model in ALS preclinical research (Picher-Martel et al., 2016). By using a computational approach, we quantify and evaluate differences between mutant and healthy mouse muscles, with the ultimate goal of identifying potential ALS image biomarkers. ...
Amyotrophic lateral sclerosis (ALS) is, to date, a fatal neurodegenerative disease that currently presents significant challenges in both diagnosis and treatment. The rapid progression and critical prognosis of the disease make accurate and prompt diagnosis crucial for enhancing ALS patient outcomes and quality of life. In this regard, the identification of ALS biomarkers is imperative for evaluating potential treatments, being SOD1 G93A murine models widely employed for their validation in preclinical studies. Here, we introduce and apply an upgraded version of NDICIA TM (Neuromuscular DIseases Computerized Image Analysis), an image analysis tool to test and quantify the presence of neuromuscular disease image biomarkers. We applied this method to examine morphological and network features in histological images of skeletal muscle biopsies acquired from SOD1 G93A and wild type (WT) mice at different stages of the disease progression: first we quantified the level of difference among mutant and WT groups of images, second we filtered out those features being the primary factors in every separation and finally we analysed how those differences and features change as the disease progresses through its different stages. This analysis revealed the way the pathology of mutant muscles evolves, differentiating from WT in muscle fibres arrangement (graph-theory properties) at presymptomatic stages, and presenting incremental atrophic-like morphological properties at later stages. In consequence, our assay pointed out muscle organization features as an important defining factor in ALS, which could be an excellent outcome measure to early detect a beneficial effect of therapeutic interventions in preclinical trials.
... Amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disorder, affects both upper and lower motor neurons, leading to muscle weakness and inability to move and breathe. The progressive motor neuron degeneration consequently results in patient death within 2 to 5 years after disease onset (https://medlineplus.gov/genetics/condition/amyotrophiclateral-sclerosis/#causes) [1][2][3]. In the past three decades, over 60 genes have been linked to ALS (https://www.als.org/ ...
... research/als-research-topics/genetics). Based on the molecular functions of ALS-linked genes, diverse pathogenic mechanisms have been associated with ALS-including protein aggregation, oxidative stress, gliosis, glutamate excitotoxicity, mitochondrial dysfunction, axonal transportation defect, ER stress, RNA metabolism, and proteasomal and autophagy impairment [2,[4][5][6][7][8][9][10]-highlighting the heterogeneity of ALS [11][12][13][14]. Moreover, in addition to the variety of ALS-linked genes, environmental factors also impact ALS phenotypes [14][15][16]. ...
... If our hypothesis is correct, we assume that Vcp overexpression is likely to ameliorate the phenotype of SOD1 mutant mice. In this report, we crossed SOD1 G93A mice, one of the most studied ALS mouse models [2,13,43], with two lines of WT Vcp transgenic mice, i.e. Vcp-H and Vcp-L [41]. ...
Many genes with distinct molecular functions have been linked to genetically heterogeneous amyotrophic lateral sclerosis (ALS), including SuperOxide Dismutase 1 (SOD1) and Valosin-Containing Protein (VCP). SOD1 converts superoxide to oxygen and hydrogen peroxide. VCP acts as a chaperon to regulate protein degradation and synthesis and various other cellular responses. Although the functions of these two genes differ, in the current report we show that overexpression of wild-type VCP in mice enhances lifespan and maintains the size of neuromuscular junctions (NMJs) of both male and female SOD1G93A mice, a well-known ALS mouse model. Although VCP exerts multiple functions, its regulation of ER formation and consequent protein synthesis has been shown to play the most important role in controlling dendritic spine formation and social and memory behaviors. Given that SOD1 mutation results in protein accumulation and aggregation, it may direct VCP to the protein degradation pathway, thereby impairing protein synthesis. Since we previously showed that the protein synthesis defects caused by Vcp deficiency can be improved by leucine supplementation, to confirm the role of the VCP-protein synthesis pathway in SOD1-linked ALS, we applied leucine supplementation to SOD1G93A mice and, similar to Vcp overexpression, we found that it extends SOD1G93A mouse lifespan. In addition, the phenotypes of reduced muscle strength and fewer NMJs of SOD1G93A mice are also improved by leucine supplementation. These results support the existence of crosstalk between SOD1 and VCP and suggest a critical role for protein synthesis in ASL. Our study also implies a potential therapeutic treatment for ALS.
... This demonstrates the challenges of developing relevant ALS/FTD mouse models. The gold standard model in ALS research is a transgenic mouse expressing multiple copies of a patient SOD1 G93A mutation, which develops ALS-like pathology, neuroinflammation, and precociously dies at 5-6 months of age [56][57][58] . However, this model has manyfold overexpressed SOD1 and is not representative of > 95% ALS cases, which are not SOD1 G93A carriers and exhibit TDP-43 rather than SOD1 aggregation. ...
Optineurin is a multifunctional polyubiquitin-binding protein implicated in inflammatory signalling. Optineurin mutations are associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), neurodegenerative diseases characterised by neuronal loss, neuroinflammation, and peripheral immune disbalance. However, the pathogenic role of optineurin mutations is unclear. We previously observed no phenotype in the unmanipulated young optineurin insufficiency mice (Optn470T), designed to mimic ALS/FTD-linked truncations deficient in polyubiquitin binding. The purpose of this study was to investigate whether ageing would trigger neurodegeneration. We performed a neurological, neuropathological, and immunological characterization of ageing wild-type (WT) and Optn470T mice. No motor or cognitive differences were detected between the genotypes. Neuropathological analyses demonstrated signs of ageing including lipofuscin accumulation and microglial activation in WT mice. However, this was not worsened in Optn470T mice, and they did not exhibit TAR DNA-binding protein 43 (TDP-43) aggregation or neuronal loss. Spleen immunophenotyping uncovered T cell immunosenescence at two years but without notable differences between the WT and Optn470T mice. Conventional dendritic cells (cDC) and macrophages exhibited increased expression of activation markers in two-year-old Optn470T males but not females, although the numbers of innate immune cells were similar between genotypes. Altogether, a combination of optineurin insufficiency and ageing did not induce ALS/FTD-like immune imbalance and neuropathology in mice.
... This demonstrates the challenges of developing relevant ALS/FTD mouse models. The gold standard model in ALS research is a transgenic mouse expressing multiple copies of a patient SOD1 G93A mutation, which develops ALS-like pathology, neuroinflammation, and precociously dies at 5-6 months of age (47,48). However, this model has manyfold overexpressed SOD1 and is not representative of > 95% ALS cases, which are not SOD1 G93A carriers and exhibit TDP-43 rather than SOD1 aggregation. ...
Optineurin is a multifunctional polyubiquitin-binding protein implicated in inflammatory signalling. Optineurin mutations are associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), neurodegenerative diseases characterised by neuronal loss, neuroinflammation, and peripheral immune disbalance. However, the pathogenic role of optineurin mutations is unclear. We previously observed no phenotype in the unmanipulated young optineurin insufficiency mice (Optn470T), designed to mimic ALS/FTD-linked truncations deficient in polyubiquitin binding. The purpose of this study was to investigate whether ageing would trigger neurodegeneration. We performed a neuroimmune characterization of ageing wild-type (WT) and Optn470T mice. No motor or cognitive differences were detected between the genotypes. Neuropathological analyses demonstrated signs of ageing including lipofuscin accumulation and microglial activation. However, this was not worsened in Optn470T mice, and they did not exhibit TAR DNA-binding protein 43 (TDP-43) aggregation or neuronal loss. Spleen immunophenotyping uncovered T cell immunosenescence at two years but without notable differences between the WT and Optn470T mice. Conventional dendritic cells (cDC) and macrophages exhibited increased expression of activation markers in two-year-old Optn470T males but not females, although the numbers of innate immune cells were similar between genotypes. Altogether, a combination of optineurin insufficiency and ageing did not induce ALS/FTD-like neuropathology in mice.
... Most ALS cases are classified as sporadic (sALS ± 90%), while the remaining ±10% are familial (fALS) [3]. Clinical presentations and evolution of the disease are highly heterogeneous between patients [4], even between those carrying the same genetic profile [5]. Although ALS is invariably lethal, approximately 20% of the patients survive >5 years and 10% may survive >10 years after the onset of the first symptoms [6]. ...
... We next investigated whether changes in metabolic and immune profiles observed in human sporadic disease were also replicated in the model of inherited disease, the SOD1 G93A mouse [5,26]. By using a mouse model with a predictable disease onset at approximately 100 days of age, we investigated whether certain changes in immune and/or metabolic profile, such as deregulation of leptin occur early in disease, i.e., prior to the onset of clinical symptoms. ...
Amyotrophic lateral sclerosis (ALS) is a clinically highly heterogeneous disease with a survival rate ranging from months to decades. Evidence suggests that a systemic deregulation of immune response may play a role and affect disease progression. Here, we measured 62 different immune/metabolic mediators in plasma of sporadic ALS (sALS) patients. We show that, at the protein level, the majority of immune mediators including a metabolic sensor, leptin, were significantly decreased in the plasma of sALS patients and in two animal models of the disease. Next, we found that a subset of patients with rapidly progressing ALS develop a distinct plasma assess immune–metabolic molecular signature characterized by a differential increase in soluble tumor necrosis factor receptor II (sTNF-RII) and chemokine (C-C motif) ligand 16 (CCL16) and further decrease in the levels of leptin, mostly dysregulated in male patients. Consistent with in vivo findings, exposure of human adipocytes to sALS plasma and/or sTNF-RII alone, induced a significant deregulation in leptin production/homeostasis and was associated with a robust increase in AMP-activated protein kinase (AMPK) phosphorylation. Conversely, treatment with an AMPK inhibitor restored leptin production in human adipocytes. Together, this study provides evidence of a distinct plasma immune profile in sALS which affects adipocyte function and leptin signaling. Furthermore, our results suggest that targeting the sTNF-RII/AMPK/leptin pathway in adipocytes may help restore assess immune–metabolic homeostasis in ALS.
... In addition, we asked if and how a ubiquitous heterozygous Tbk1 knockout alters the phenotype of SOD1 G93A transgenic mice. In this ALS model, the overexpression of (human) SOD1 G93A leads to MN degeneration and neuroinflammation and represents a challenge of the proteostatic system (Philips and Rothstein, 2015;Picher-Martel et al., 2016). Thus, we crossed Tbk1 +/− mice with SOD1 G93A transgenic mice. ...
Genetics and pathomechanisms of amyotrophic lateral
sclerosis associated with mutations in the genes
TBK1, KIF5A and CACNA1A
... Despite the importance of cellular models in physiopathological understanding of ALS and other degenerative diseases, in vitro studies are not able to reflect living organism complexity. To understand the interplay of MNs and other cells, animal models with specific mutations are the gold standard in ALS studies (Picher-Martel et al. 2016). ...
Amyotrophic lateral sclerosis (ALS) is a fatal illness characterized by progressive motor neuron degeneration. Conventional therapies for ALS are based on treatment of symptoms, and the disease remains incurable. Molecular mechanisms are unclear, but studies have been pointing to involvement of glia, neuroinflammation, oxidative stress, and glutamate excitotoxicity as a key factor. Nowadays, we have few treatments for this disease that only delays death, but also does not stop the neurodegenerative process. These treatments are based on glutamate blockage (riluzole), tyrosine kinase inhibition (masitinib), and antioxidant activity (edaravone). In the past few years, plant-derived compounds have been studied for neurodegenerative disorder therapies based on neuroprotection and glial cell response. In this review, we describe mechanisms of action of natural compounds associated with neuroprotective effects, and the possibilities for new therapeutic strategies in ALS.
... For 5-10 % of genetically-driven cases, mutations in -synuclein, leucine repeat kinase 2 (LRRK2), parkin, DJ1 (PARK7), or PTEN-induced putative kinase 1 (PINK1) enable the development of animal models (Blesa and Przedborski, 2014;Poewe et al., 2017). Other neurodegenerative diseases have been modeled using transgenic rodents as well, such as overexpression of TDP-43 or mutations of superoxide dismutase 1 (SOD1) or C9orf72 to elicit amyotrophic lateral sclerosis (ALS) phenotypes of motor neuron degeneration and cognitive defects (Philips and Rothstein, 2015;Picher-Martel et al., 2016). Despite these advancements, neurodegenerative disease drugs developed using animal models often fail in clinical trials due to insufficient recapitulation of disease phenotypes and poor translatability from animals to human patients (Beal, 2010;Jucker, 2010;Anderson et al., 2017;Dawson et al., 2018;Ransohoff, 2018). ...
... Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, involves loss of motor neurons that causes progressive muscle atrophy and paralysis, which in turn leads to death within 2 to 5 years of disease onset (Picher-Martel et al., 2016). Identification of several key mutations associated with the familial form of the disease and related animal models have advanced the current understanding of ALS pathophysiology. ...
Disease models enable researchers to investigate, test, and identify therapeutic targets that would alter patients' disease condition and improve quality of life. Advancements in genetic alteration and analytical techniques have enabled rapid development of disease models using preclinical animals and cell cultures. However, success rates of drug development remain low due to limited recapitulation of clinical pathophysiology by these models. To resolve this challenge, the pharmaceutical industry has explored microphysiological system (MPS) disease models, which are complex in vitro systems that include but are not limited to organ-on-a-chip, organoids, spheroids, and 3D bioengineered tissues (e.g., 3D printing, hydrogels). Capable of integrating key in vivo properties, such as disease-relevant human cells, multi-cellularity/dimensionality of organs, and/or well-controlled physical and molecular cues, MPS disease models are being developed for a variety of indications. With on-going qualifications or validations for wide adoption within the pharmaceutical industry, MPS disease models hold exciting potential to enable in-depth investigation of in vivo pathophysiology and enhance drug discovery and development processes. To introduce the present status of MPS disease models, this paper describes notable examples in six disease areas: cancer, liver/kidney diseases, respiratory diseases/COVID-19, neurodegenerative diseases, gastrointestinal diseases, and select rare diseases. Additionally, we describe current technical limitations and provide recommendations for future development that would expand application opportunities within the pharmaceutical industry.
... Case note review did not reveal significant cognitive impairment. Another individual had the SOD1 p.(Gly38Arg) variant; this variant is associated with a mouse model of ALS which recapitulates some of the motor features [35]. However, there is a paucity of knowledge regarding its phenotypic correlates. ...
Background
We investigated the phenotypes and genotypes of a cohort of ‘long-surviving’ individuals with motor neuron disease (MND) to identify potential targets for prognostication.
Methods
Patients were recruited via the Clinical Audit Research and Evaluation for MND (CARE-MND) platform, which hosts the Scottish MND Register. Long survival was defined as > 8 years from diagnosis. 11 phenotypic variables were analysed. Whole genome sequencing (WGS) was performed and variants within 49 MND-associated genes examined. Each individual was screened for C9orf72 repeat expansions. Data from ancestry-matched Scottish populations (the Lothian Birth Cohorts) were used as controls.
Results
58 long survivors were identified. Median survival from diagnosis was 15.5 years. Long survivors were significantly younger at onset and diagnosis than incident patients and had a significantly longer diagnostic delay. 42% had the MND subtype of primary lateral sclerosis (PLS). WGS was performed in 46 individuals: 14 (30.4%) had a potentially pathogenic variant. 4 carried the known SOD1 p.(Ile114Thr) variant. Significant variants in FIG4 , hnRNPA2B1, SETX, SQSTM1, TAF15, and VAPB were detected. 2 individuals had a variant in the SPAST gene suggesting phenotypic overlap with hereditary spastic paraplegia (HSP). No long survivors had pathogenic C9orf72 repeat expansions.
Conclusions
Long survivors are characterised by younger age at onset, increased prevalence of PLS and longer diagnostic delay. Genetic analysis in this cohort has improved our understanding of the phenotypes associated with the SOD1 variant p.(Ile114Thr). Our findings confirm that pathogenic expansion of C9orf72 is likely a poor prognostic marker. Genetic screening using targeted MND and/or HSP panels should be considered in those with long survival, or early-onset slowly progressive disease, to improve diagnostic accuracy and aid prognostication.
... Several ALS/FTD mouse models of TDP-43 report that expression of ALS-linked mutations, cause brain atrophy, muscle denervation, motor neuron loss, and denervation of NMJs along with progressive motor impairments (McGoldrick et al., 2013;Picher-Martel et al., 2016;White et al., 2018;Ebstein et al., 2019;Huang et al., 2020;Alhindi et al., 2021). Mice overexpressing TDP-43Q331K or wild-type human TDP-43 (TDP-43WT), in the brain and spinal cord under control of the murine prion promoter (Prp), showed dose and age-dependent motor defects caused by mutant TDP-43, which corresponded with progressive motor axon degeneration, motor neuron death and denervation of NMJs (Arnold et al., 2013). ...
... Several mouse models of ALS/FTD-FUS display similar aspects of the human disease, including changes to neuronal morphology and synapses, as well as cognitive and motor defects (McGoldrick et al., 2013;Picher-Martel et al., 2016;Alhindi et al., 2021). Global transgenic mice expressing low levels human wild-type FUS (FUSWT) or FUSR521G under Cre-inducible control of the CAG promoter, developed deficits in motor function, NMJ denervation and inflammation without the loss of motor neurons, degeneration of motor axons or FUS aggregation (Sephton et al., 2014). ...
Synaptic loss is a pathological feature of all neurodegenerative diseases
including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia
(FTD). ALS is a disease of the cortical and spinal motor neurons resulting
in fatal paralysis due to denervation of muscles. FTD is a form of dementia
that primarily affects brain regions controlling cognition, language and
behavior. Once classified as two distinct diseases, ALS and FTD are now
considered as part of a common disease spectrum based on overlapping
clinical, pathological and genetic evidence. At the cellular level, aggregation
of common proteins and overlapping gene susceptibilities are shared in both
ALS and FTD. Despite the convergence of these two fields of research, the
underlying disease mechanisms remain elusive. However, recent discovers
from ALS and FTD patient studies and models of ALS/FTD strongly suggests
that synaptic dysfunction is an early event in the disease process and a
unifying hallmark of these diseases. This review provides a summary of the
reported anatomical and cellular changes that occur in cortical and spinal
motor neurons in ALS and FTD tissues and models of disease. We also
highlight studies that identify changes in the proteome and transcriptome of
ALS and FTD models and provide a conceptual overview of the processes that
contribute to synaptic dysfunction in these diseases. Due to space limitations
and the vast number of publications in the ALS and FTD fields, many articles
have not been discussed in this review. As such, this review focuses on the
three most common shared mutations in ALS and FTD, the hexanucleuotide
repeat expansion within intron 1 of chromosome 9 open reading frame
72 (C9ORF72), transactive response DNA binding protein 43 (TARDBP or
TDP-43) and fused in sarcoma (FUS), with the intention of highlighting
common pathways that promote synaptic dysfunction in the ALS-FTD disease
spectrum.
