Amyotrophic Lateral Sclerosis Pathology Research Articles

Differential regulation of L84F SOD1 in motor neurons and skeletal muscles: an insight into ALS pathology

Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disorder characterized by progressive deterioration of motor neurons leading to skeletal muscle denervation. Recent evidences have highlighted early involvement of neuromuscular junction (NMJ) in ALS pathogenesis. NMJ is a specialized tripartite chemical synapse which involves a well‐coordinated communication among the presynaptic motor neuron, postsynaptic skeletal muscle and terminal Schwann cells. Despite several evidences, series of events triggering NMJ disassembly in ALS are still obscure.The aim of our study is to investigate the cellular and molecular mechanisms of NMJ dysfunction in an in vitro Superoxide Dismutase 1 (SOD1) induced model of familial ALS. We have generated an ALS cell model based on a novel SOD1 mutation (L84F) identified previously in a family with a history of ALS. This mutation caused decrease in neurite outgrowth which led us to hypothesize that it may be involved in neuromuscular junction disassembly in ALS pathology.We have characterized cellular components of NMJ by differentiating hybrid spinal cord cell line (NSC‐34) into motor neurons and myoblast cell line (C2C12) into myotubes. Expression of mutant SOD1 led to decrease in mitochondrial footprints in axons and synaptic terminals and altered mitochondrial dynamics in motor neurons. However mitochondrial fission/fusion is not altered in muscles suggesting differential consequences of mutant protein. L84F SOD1 mutant readily formed detergent‐resistant aggregates in motor neurons but failed to accumulate in skeletal muscles. Skeletal muscles displayed increased levels of LC3‐II compared to motor neurons suggesting a robust proteasome machinery of muscles is responsible for clearance of mutant protein. Furthermore, motor neurons exhibited increased cell death compared to skeletal muscles when subjected to exogenous stress. Interestingly, we observed that condition media from skeletal muscles was able to rescue motor neurons from exogenous stress. We are currently identifying paracrine neuroprotective factors secreted by the muscles. It is noteworthy that mutant SOD1 led to altered expression of post synaptic acetylcholine receptor complex which might hamper neuromuscular transmission in ALS.To conclude, molecular cues from both neurons and muscles appear to play a role in compromising NMJ integrity in ALS.

Identifying Therapeutic Inhibitors of TDP43 Phase‐Separation

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease for which there has been little improvement in treatment over the past 25 years. ALS is linked to mutations in dozens of genes, but despite its genetic complexity, 97% of patients share a distinct molecular pathology: cytoplasmic inclusions of TAR DNA‐Binding protein 43 (TDP‐43). Further, TDP‐43 aggregates are toxic to healthy neurons, suggesting that TDP‐43 aggregates contribute to neurodegeneration in ALS. Due to the near‐ubiquity of TDP‐43 inclusions in ALS patients and their contribution to ALS pathology, prevention or dissolution of these TDP‐43 inclusions presents a promising therapeutic strategy. In cells, TDP43 can form both solid aggregates or liquid droplets, through liquid‐liquid phase separation (LLPS). Here, we screened a library of small molecules and RNAs to identify inhibitors of TDP‐43 LLPS using an in vitro assay which quantifies TDP‐43 liquid droplet formation. Hits from this screen were further characterized based on their ability to reverse and inhibit both TDP‐43 droplets and aggregates to obtain functional profiles for each promising inhibitor. Pairing functional data of inhibitors with structural information regarding their binding to TDP‐43 enables a close‐dissection of the interactions that drive TDP‐43 self‐assembly. Thus, small molecule screens which target protein self‐assembly present a powerful approach for both developing novel therapeutics and identifying the interactions that govern self‐assembly; these inform each other and may lead to the discovery of novel therapeutic agents which target protein self‐assembly to treat severe diseases, like ALS.

Motor Neuron Diseases

The motor neuron diseases (MNDs) are a family of diseases commonly categorized by their propensity to affect upper or lower motor neurons and by their mode of inheritance. The chapter provides some content on infectious MNDs caused by viral infections affecting the motor neurons in the anterior horn of the spinal cord. However, the chapter devotes most of its attention to the inherited and sporadically occurring MNDs. The majority of research into adult MND focuses on amyotrophic lateral sclerosis (ALS) due to its high prevalence, rapid progression, and phenotypical similarities between its inherited form and its sporadic form. As our knowledge of genetic mechanisms underlying ALS pathology has grown, common themes have emerged. These include abnormalities in RNA biology, axonal transport, protein folding, and inflammatory responses. These themes currently drive much of the direction in ALS experimental therapy development. It is clear that MND is complex and involves several different molecular pathways. Given this complexity, ALS might not be a single disease entity, and if this is the case, treatment approaches may need to be targeted to specific pathologies rather than all ALS patients on a broad scale. Chapter content is enhanced by tables outlining the types of MNDs, criteria for supporting a diagnosis, first-line workup, the genes associated with ALS, ALS efficacy outcome measures, symptom management of ALS, and spinal muscular atrophy classification. Mechanisms of ALS are illustrated, and clinical photographs demonstrate symptoms. This review contains 5 figures, 14 tables and 253 references Keywords: motor neuron disease, amyotrophic lateral sclerosis, electromyography, Guillain-Barré syndrome

Motor Neuron Diseases

The motor neuron diseases (MNDs) are a family of diseases commonly categorized by their propensity to affect upper or lower motor neurons and by their mode of inheritance. The chapter provides some content on infectious MNDs caused by viral infections affecting the motor neurons in the anterior horn of the spinal cord. However, the chapter devotes most of its attention to the inherited and sporadically occurring MNDs. The majority of research into adult MND focuses on amyotrophic lateral sclerosis (ALS) due to its high prevalence, rapid progression, and phenotypical similarities between its inherited form and its sporadic form. As our knowledge of genetic mechanisms underlying ALS pathology has grown, common themes have emerged. These include abnormalities in RNA biology, axonal transport, protein folding, and inflammatory responses. These themes currently drive much of the direction in ALS experimental therapy development. It is clear that MND is complex and involves several different molecular pathways. Given this complexity, ALS might not be a single disease entity, and if this is the case, treatment approaches may need to be targeted to specific pathologies rather than all ALS patients on a broad scale. Chapter content is enhanced by tables outlining the types of MNDs, criteria for supporting a diagnosis, first-line workup, the genes associated with ALS, ALS efficacy outcome measures, symptom management of ALS, and spinal muscular atrophy classification. Mechanisms of ALS are illustrated, and clinical photographs demonstrate symptoms. This review contains 5 figures, 14 tables and 253 references Keywords: motor neuron disease, amyotrophic lateral sclerosis, electromyography, Guillain-Barré syndrome

Motor Neuron Diseases

The motor neuron diseases (MNDs) are a family of diseases commonly categorized by their propensity to affect upper or lower motor neurons and by their mode of inheritance. The chapter provides some content on infectious MNDs caused by viral infections affecting the motor neurons in the anterior horn of the spinal cord. However, the chapter devotes most of its attention to the inherited and sporadically occurring MNDs. The majority of research into adult MND focuses on amyotrophic lateral sclerosis (ALS) due to its high prevalence, rapid progression, and phenotypical similarities between its inherited form and its sporadic form. As our knowledge of genetic mechanisms underlying ALS pathology has grown, common themes have emerged. These include abnormalities in RNA biology, axonal transport, protein folding, and inflammatory responses. These themes currently drive much of the direction in ALS experimental therapy development. It is clear that MND is complex and involves several different molecular pathways. Given this complexity, ALS might not be a single disease entity, and if this is the case, treatment approaches may need to be targeted to specific pathologies rather than all ALS patients on a broad scale. Chapter content is enhanced by tables outlining the types of MNDs, criteria for supporting a diagnosis, first-line workup, the genes associated with ALS, ALS efficacy outcome measures, symptom management of ALS, and spinal muscular atrophy classification. Mechanisms of ALS are illustrated, and clinical photographs demonstrate symptoms. This review contains 5 figures, 14 tables and 253 references Keywords: motor neuron disease, amyotrophic lateral sclerosis, electromyography, Guillain-Barré syndrome

Motor Neuron Diseases

The motor neuron diseases (MNDs) are a family of diseases commonly categorized by their propensity to affect upper or lower motor neurons and by their mode of inheritance. The chapter provides some content on infectious MNDs caused by viral infections affecting the motor neurons in the anterior horn of the spinal cord. However, the chapter devotes most of its attention to the inherited and sporadically occurring MNDs. The majority of research into adult MND focuses on amyotrophic lateral sclerosis (ALS) due to its high prevalence, rapid progression, and phenotypical similarities between its inherited form and its sporadic form. As our knowledge of genetic mechanisms underlying ALS pathology has grown, common themes have emerged. These include abnormalities in RNA biology, axonal transport, protein folding, and inflammatory responses. These themes currently drive much of the direction in ALS experimental therapy development. It is clear that MND is complex and involves several different molecular pathways. Given this complexity, ALS might not be a single disease entity, and if this is the case, treatment approaches may need to be targeted to specific pathologies rather than all ALS patients on a broad scale. Chapter content is enhanced by tables outlining the types of MNDs, criteria for supporting a diagnosis, first-line workup, the genes associated with ALS, ALS efficacy outcome measures, symptom management of ALS, and spinal muscular atrophy classification. Mechanisms of ALS are illustrated, and clinical photographs demonstrate symptoms. This review contains 5 figures, 14 tables and 253 references Keywords: motor neuron disease, amyotrophic lateral sclerosis, electromyography, Guillain-Barré syndrome

FV 3 Cytoskeletal analysis in sensory nerve fibre endings show a decrease of neurofilaments in high aggressive spinal Amyotrophic lateral sclerosis

Introduction: Amyotrophic lateral sclerosis (ALS) is a multisystemic, neurodegenerative disease, which is characterized by distal axonopathy and motor neuron loss and thereby leads to muscular weakness and death during 3-5 years after symptom onset due to respiratory failure. Neurofilaments are well-established biomarkers in ALS as they show increased levels in CSF compared to healthy controls as an expression of axonal damage and predict disease aggressiveness (by using the D50 progression model) and survival in ALS [1]. Together with their posttranslational modifications, neurofilaments and microtubules are critical components in cytoskeletal pathology of motor neuron diseases. Also, there are several ALS-related genes known to directly affect cytoskeletal dynamics, like TUBA4A, KIF5A or DCTNI1, which can interfere axon stability and axonal transport. In this study, we investigate the cytoskeleton in sensory nerve fiber endings of ALS patients to get a closer look in axonal pathology in ALS. Material and Methods: We performed skin biopsies of the proximal and distal leg in ALS and healthy controls. Those were immunostained for microtubules (ßIII-tubulin), neurofilaments (phosphorylated/non-phosphorylated neurofilaments – pNfH/npNfH) and actin and the individual fibres were analyzed for mean grey value intensity and axonal caliber in confocal images of the dermis. Additionally, we added electron microscopy (EM) of the biopsies to evaluate accumulation of cytoskeleton components or disorders in organelle transport. By using the D50 progression modell, based on functional loss in ALSFRS-R score, we also included the individual disease course and evaluate disease aggressiveness and disease accumulation for each ALS patients. Results: Our preliminary results show that ALS patients have an increase of mean grey value intensities for neurofilaments, ßIII-tubulin and actin compared to healthy controls. In subgroup analysis of ALS, compared by disease onset and disease aggressiveness, we see a trend for decrease in high aggressive spinal and bulbar ALS vs. low aggressive spinal ALS. Also, EM shows organelle transport disorders like mitochondrial accumulation in sensory nerve fibre endings in some cases of ALS. Conclusion: Analysis of skin biopsies may provide a simple tool to study axonal pathology in ALS and may be useful to predict disease aggressiveness as neurofilaments in sensory nerve fibre endings show a decrease in high aggressive spinal ALS. Further, we want to take a closer look to posttranslational modifications of microtubules, investigate the length dependence (proximal vs. distal), add longitudinal analysis and also correlate the results with clinical data and biomarkers, eg. neurofilaments in serum and CSF.

Accumulation of Nonfibrillar TDP-43 in the Rough Endoplasmic Reticulum Is the Early-Stage Pathology in Amyotrophic Lateral Sclerosis.

Transactivation response DNA-binding protein 43 (TDP-43)-immunoreactive neuronal cytoplasmic inclusions (NCIs) are the histopathological hallmarks of amyotrophic lateral sclerosis (ALS). They are classified as skein-like inclusions, round inclusions, dot-like inclusions, linear wisps, and diffuse punctate cytoplasmic staining (DPCS). We hypothesized that TDP-43-immunoreactive DPCS may form the early-stage pathology of ALS. Hence, we investigated phosphorylated TDP-43 pathology in the upper and lower motor neurons of patients with ALS and control participants. We designated patients whose disease duration was ≤1 year as short-duration ALS (n = 7) and those whose duration equaled 3-5 years as standard-duration ALS (n = 6). DPCS and skein-like inclusions were the most common NCIs in short-duration and standard-duration ALS, respectively. The density of DPCS was significantly higher in short-duration ALS than that in standard-duration ALS and was inversely correlated with disease duration. DPCS was not ubiquitinated and disappeared after proteinase K treatment, suggesting that it was not aggregated. Immunoelectron microscopy revealed that DPCS corresponded to nonfibrillar TDP-43 localized to the ribosomes of the rough endoplasmic reticulum (ER). These findings suggest that nonfibrillar TDP-43 accumulation in the rough ER is the earliest TDP-43 pathology in ALS, which may be helpful in developing future TDP-43 breakdown strategies for ALS.

Preclinical evaluation of a microtubule PET ligand [11C]MPC-6827 in tau and amyotrophic lateral sclerosis animal models.

Microtubules are abundant in brain and their malfunctioning occurs in the early-to-advanced stages of neurodegenerative disorders. At present, there is no in vivo test available for a definitive diagnosis of most of the neurodegenerative disorders. Herein, we present the microPET imaging of microtubules using our recently reported Positron Emission Tomography (PET) tracer, [11C]MPC-6827, in transgenic mice models of tau pathology (rTg4510) and amyotrophic lateral sclerosis pathology (SOD1*G93A) and compared to corresponding age-matched controls. Automated synthesis of [11C]MPC-6827 was achieved in a GE-FX2MeI/FX2M radiochemistry module. In vivo PET imaging studies of [11C]MPC-6827 (3.7 ± 0.8MBq) were performed in rTg4510 and SOD1*G93A mice groups and their corresponding littermates (n = 5 per group). Dynamic PET images were acquired using a microPET Inveon system (Siemens, Germany) at 55min for rTg4510 and 30min for SOD1*G93A and corresponding controls. PET images were reconstructed using the 3D-OSEM algorithm and analyzed using VivoQuant version 4 (Invicro, MA). Tracer uptake in ROIs that included whole brain was measured as %ID/g over time to generate standardized uptake values (SUV) and time-activity curves (TACs). [11C]MPC-6827 exhibit a trend of lower tracer binding in mouse models of Alzheimer's disease (tau pathology, line rTg4510) and Amyotrophic Lateral Sclerosis (line SOD1*G93A) compared to wild-type littermates. Our finding indicates a trend of loss of microtubule binding of [11C]MPC-6827 in the whole brain of AD and ALS transgenic mice models compared to control mice. The pilot studies described herein show that [11C]MPC-6827 could be used as a PET ligand for preclinical and human brain imaging of Alzheimer's disease, ALS, and other neurodegenerative diseases. Preclinical Evaluation of a Microtubule PET Ligand [11C]MPC-6827 in Tau and Amyotrophic Lateral Sclerosis Animal Models. J. S. Dileep Kumar, Andrei Molotkov, Jongho Kim, Patrick Carberry, Sidney Idumonyi, John Castrillon, Karen Duff, Neil A. Shneider, Akiva Mintz.

USP10 Inhibits Aberrant Cytoplasmic Aggregation of TDP-43 by Promoting Stress Granule Clearance.

TAR DNA-binding protein 43 (TDP-43) is a causative factor of amyotrophic lateral sclerosis (ALS). Cytoplasmic TDP-43 aggregates in neurons are a hallmark pathology of ALS. Under various stress conditions, TDP-43 localizes sequentially to two cytoplasmic protein aggregates, namely, stress granules (SGs) first and then aggresomes. Accumulating evidence suggests that delayed clearance of TDP-43-positive SGs is associated with pathological TDP-43 aggregates in ALS. We found that ubiquitin-specific protease 10 (USP10) promotes the clearance of TDP-43-positive SGs in cells treated with proteasome inhibitor, thereby promoting the formation of TDP-43-positive aggresomes, and the depletion of USP10 increases the amount of insoluble TDP-35, a cleaved product of TDP-43, in the cytoplasm. TDP-35 interacted with USP10 in an RNA-binding-dependent manner; however, impaired RNA binding of TDP-35 reduced the localization in SGs and aggresomes and induced USP10-negative TDP-35 aggregates. Immunohistochemistry showed that most of the cytoplasmic TDP-43/TDP-35 aggregates in the neurons of ALS patients were USP10 negative. Our findings suggest that USP10 inhibits aberrant aggregation of TDP-43/TDP-35 in the cytoplasm of neuronal cells by promoting the clearance of TDP-43/TDP-35-positive SGs and facilitating the formation of TDP-43/TDP-35-positive aggresomes.

Muscle cells of sporadic amyotrophic lateral sclerosis patients secrete neurotoxic vesicles.

BackgroundThe cause of the motor neuron (MN) death that drives terminal pathology in amyotrophic lateral sclerosis (ALS) remains unknown, and it is thought that the cellular environment of the MN may play a key role in MN survival. Several lines of evidence implicate vesicles in ALS, including that extracellular vesicles may carry toxic elements from astrocytes towards MNs, and that pathological proteins have been identified in circulating extracellular vesicles of sporadic ALS patients. Because MN degeneration at the neuromuscular junction is a feature of ALS, and muscle is a vesicle‐secretory tissue, we hypothesized that muscle vesicles may be involved in ALS pathology.MethodsSporadic ALS patients were confirmed to be ALS according to El Escorial criteria and were genotyped to test for classic gene mutations associated with ALS, and physical function was assessed using the ALSFRS‐R score. Muscle biopsies of either mildly affected deltoids of ALS patients (n = 27) or deltoids of aged‐matched healthy subjects (n = 30) were used for extraction of muscle stem cells, to perform immunohistology, or for electron microscopy. Muscle stem cells were characterized by immunostaining, RT‐qPCR, and transcriptomic analysis. Secreted muscle vesicles were characterized by proteomic analysis, Western blot, NanoSight, and electron microscopy. The effects of muscle vesicles isolated from the culture medium of ALS and healthy myotubes were tested on healthy human‐derived iPSC MNs and on healthy human myotubes, with untreated cells used as controls.ResultsAn accumulation of multivesicular bodies was observed in muscle biopsies of sporadic ALS patients by immunostaining and electron microscopy. Study of muscle biopsies and biopsy‐derived denervation‐naïve differentiated muscle stem cells (myotubes) revealed a consistent disease signature in ALS myotubes, including intracellular accumulation of exosome‐like vesicles and disruption of RNA‐processing. Compared with vesicles from healthy control myotubes, when administered to healthy MNs the vesicles of ALS myotubes induced shortened, less branched neurites, cell death, and disrupted localization of RNA and RNA‐processing proteins. The RNA‐processing protein FUS and a majority of its binding partners were present in ALS muscle vesicles, and toxicity was dependent on the expression level of FUS in recipient cells. Toxicity to recipient MNs was abolished by anti‐CD63 immuno‐blocking of vesicle uptake.ConclusionsALS muscle vesicles are shown to be toxic to MNs, which establishes the skeletal muscle as a potential source of vesicle‐mediated toxicity in ALS.

Emerging Roles for Phase Separation of RNA-Binding Proteins in Cellular Pathology of ALS.

Liquid-liquid phase separation (LLPS) is emerging as a major principle for the mesoscale organization of proteins, RNAs, and membrane-bound organelles into biomolecular condensates. These condensates allow for rapid cellular responses to changes in metabolic activities and signaling. Nowhere is this regulation more important than in neurons and glia, where cellular physiology occurs simultaneously on a range of time- and length-scales. In a number of neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis (ALS), misregulation of biomolecular condensates leads to the formation of insoluble aggregates—a pathological hallmark of both sporadic and familial ALS. Here, we summarize how the emerging knowledge about the LLPS of ALS-related proteins corroborates with their aggregation. Understanding the mechanisms that lead to protein aggregation in ALS and how cells respond to these aggregates promises to open new directions for drug development.

Tetrabutylammonium based ionic liquids (ILs) inhibit the amyloid aggregation of superoxide dismutase 1 (SOD1)

Aggregation of a protein is associated with several biological and industrial processes: some wanted and some unwanted. An understanding of the mechanism of modulation of aggregation is, thus, required for designing strategies for the prevention/enhancement of amyloids. Misfolding and aggregation of human Cu-Zn superoxide dismutase (SOD1) into amyloid aggregates is a hallmark of a fatal neurodegenerative disease, amyotrophic lateral sclerosis (ALS). Therefore, targeting SOD1 protein could be a good choice for understanding the mechanism of SOD1 pathology in ALS. Here, we study the inhibitory effect of ammonium and choline based ionic liquids (ILs) (tetrabutylammonium methanesulfonate (TBAMS), tetrabutylammonium chloride (TBACl) and choline chloride (CholCl) on amyloid aggregation of SOD1 and explore how ILs modulate the formation of amyloid aggregates.We demonstrate that aqueous solutions of TBAMS and TBACl effectively inhibit SOD1 fibrillation, and their inhibitory effect increased with increasing the concentration. Conversely, CholCl has been found to act as an amyloid inhibitor at lower concentrations by acting at the elongation step and as an amyloid promoter at higher concentrations. Our experimental results showed that TBAMS and TBACl induce the formation of compact structures with reduced hydrophobicity. Theoretical analysis revealed that ILs stabilize Zn binding loop and electrostatic loop which play an important role in the structure and function of SOD1. These findings provide important insights about using IL as an anti-amyloidal agent for other amyloidogenic proteins and help to design effective modulators for protein aggregation.

Modeling seeding and neuroanatomic spread of pathology in amyotrophic lateral sclerosis

The neurodegenerative disorder amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of upper and lower motor neurons, with pathological involvement of cerebral motor and extra-motor areas in a clinicopathological spectrum with frontotemporal dementia (FTD). A key unresolved issue is how the non-random distribution of pathology in ALS reflects differential network vulnerability, including molecular factors such as regional gene expression, or preferential spread of pathology via anatomical connections. A system of histopathological staging of ALS based on the regional burden of TDP-43 pathology observed in postmortem brains has been supported to some extent by analysis of distribution of in vivo structural MRI changes. In this paper, computational modeling using a Network Diffusion Model (NDM) was used to investigate whether a process of focal pathological ‘seeding’ followed by structural network-based spread recapitulated postmortem histopathological staging and, secondly, whether this had any correlation to the pattern of expression of a panel of genes implicated in ALS across the healthy brain. Regionally parcellated T1-weighted MRI data from ALS patients (baseline n=79) was studied in relation to a healthy control structural connectome and a database of associated regional cerebral gene expression. The NDM provided strong support for a structural network-based basis for regional pathological spread in ALS, but no simple relationship to the spatial distribution of ALS-related genes in the healthy brain. Interestingly, OPTN gene was identified as a significant but a weaker non-NDM contributor within the network-gene interaction model (LASSO). Intriguingly, the critical seed regions for spread within the model were not within the primary motor cortex but basal ganglia, thalamus and insula, where NDM recapitulated aspects of the postmortem histopathological staging system. Within the ALS-FTD clinicopathological spectrum, non-primary motor structures may be among the earliest sites of cerebral pathology.

Expanding the TDP-43 Proteinopathy Pathway From Neurons to Muscle: Physiological and Pathophysiological Functions.

TAR DNA-binding protein 43, mostly referred to as TDP-43 (encoded by the TARDBP gene) is strongly linked to the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). From the identification of TDP-43 positive aggregates in the brains and spinal cords of ALS/FTD patients, to a genetic link between TARBDP mutations and the development of TDP-43 pathology in ALS, there is strong evidence indicating that TDP-43 plays a pivotal role in the process of neuronal degeneration. What this role is, however, remains to be determined with evidence ranging from gain of toxic properties through the formation of cytotoxic aggregates, to an inability to perform its normal functions due to nuclear depletion. To add to an already complex subject, recent studies highlight a role for TDP-43 in muscle physiology and disease. We here review the biophysical, biochemical, cellular and tissue-specific properties of TDP-43 in the context of neurodegeneration and have a look at the nascent stream of evidence that positions TDP-43 in a myogenic context. By integrating the neurogenic and myogenic pathological roles of TDP-43 we provide a more comprehensive and encompassing view of the role and mechanisms associated with TDP-43 across the various cell types of the motor system, all the way from brain to limbs.

Stem Cells From Human Exfoliated Deciduous Teeth-Conditioned Medium (SHED-CM) is a Promising Treatment for Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, characterized by the loss of upper and lower motor neurons, for which an effective treatment has yet to be developed. Previous reports have shown that excessive oxidative stress, related to mitochondrial dysfunction and the accumulation of misfolding protein, contributes to ALS pathology. In terms of treatment, it remains necessary to identify effective medicines for multiple therapeutic targets and have additive effects against several disorders. In this study, we investigated stem cells from human exfoliated deciduous teeth (SHED), which release many factors, such as neurotrophic factors and cytokines, and are applied to treat neurological diseases. Specifically, we examined whether SHED-conditioned medium (CM), i.e., the serum-free culture supernatant of SHED, reduced mutant SOD1-induced intracellular aggregates and neurotoxicity. We found that SHED-CM significantly suppressed the mutant SOD1-induced intracellular aggregates and neurotoxicity. The neuroprotective effects of SHED-CM are partly related to heat shock protein and the activation of insulin-like growth factor-1 receptor. SHED-CM also had a protective effect on induced pluripotent stem cell-derived motor neurons. Moreover, SHED-CM was effective against not only familial ALS but also sporadic ALS. Overall, these results suggest that SHED-CM could be a promising treatment for slowing the progression of ALS.

Genome-wide identification of the genetic basis of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a complex disease that leads to motor neuron death. Despite heritability estimates of 52%, genome-wide association studies (GWASs) have discovered relatively few loci. We developed a machine learning approach called RefMap, which integrates functional genomics with GWAS summary statistics for gene discovery. With transcriptomic and epigenetic profiling of motor neurons derived from induced pluripotent stem cells (iPSCs), RefMap identified 690 ALS-associated genes that represent a 5-fold increase in recovered heritability. Extensive conservation, transcriptome, network, and rare variant analyses demonstrated the functional significance of candidate genes in healthy and diseased motor neurons and brain tissues. Genetic convergence between common and rare variation highlighted KANK1 as a new ALS gene. Reproducing KANK1 patient mutations in human neurons led to neurotoxicity and demonstrated that TDP-43 mislocalization, a hallmark pathology of ALS, is downstream of axonal dysfunction. RefMap can be readily applied to other complex diseases.

Motor cortical patterns of upper motor neuron pathology in amyotrophic lateral sclerosis: A 3 T MRI study with iron-sensitive sequences

BackgroundPatterns of initiation and propagation of disease in Amyotrophic Lateral Sclerosis (ALS) are still partly unknown. Single or multiple foci of neurodegeneration followed by disease diffusion to contiguous or connected regions have been proposed as mechanisms underlying symptom occurrence. Here, we investigated cortical patterns of upper motor neuron (UMN) pathology in ALS using iron-sensitive MR imaging. MethodsSignal intensity and magnetic susceptibility of the primary motor cortex (M1), which are associated with clinical UMN burden and neuroinflammation, were assessed in 78 ALS patients using respectively T2*-weighted images and Quantitative Susceptibility Maps. The signal intensity of the whole M1 and each of its functional regions was rated as normal or reduced, and the magnetic susceptibility of each M1 region was measured. ResultsThe highest frequencies of T2* hypointensity were found in M1 regions associated with the body sites of symptom onset. Homologous M1 regions were both hypointense in 80–93 % of patients with cortical abnormalities, and magnetic susceptibility values measured in homologous M1 regions were strongly correlated with each other (ρ = 0.88; p < 0.0001). In some cases, the T2* hypointensity was detectable in two non-contiguous M1 regions but spared the cortex in between. ConclusionsM1 regions associated with the body site of onset are frequently affected at imaging. The simultaneous involvement of both homologous M1 regions is frequent, followed by that of adjacent regions; the affection of non-contiguous regions, instead, seems rare. This type of cortical involvement suggests the interhemispheric connections as one of the preferential paths for the UMN pathology diffusion in ALS.

Glucose metabolism in amyotrophic lateral sclerosis: it is bitter-sweet.

Glucose metabolism in amyotrophic lateral sclerosis: it is bitter-sweet.

Motor behavioral abnormalities and histopathological findings in middle aged male Wistar rats inoculated with cerebrospinal fluid from patients with Amyotrophic Lateral Sclerosis

• Middle-aged male rats infused with CSF mimic pathogenic mechanisms observed in ALS. • Infusion of human CSF from patients of ALS causes motor impairment in middle-aged animals. • CSF from patients of ALS is a tool to investigate the characteristics of the disease. Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease associated with loss of upper and lower motor neurons in the primary motor cortex and spinal cord, respectively. Motor deficits are the main clinical features observed in patients with the disease. However, it has been suggested that the presence of neurotoxic factors in the cerebrospinal fluid (CSF) from ALS patients causes loss of motor neurons. The present study investigated the motor and histopathological changes induced by intracerebroventricular (ICV) infusion of CSF from ALS patients in middle aged male Wistar rats. Middle aged male rats were divided into three groups: (1) control group, animals injected with artificial CSF solution; (2) N-ALS group, animals injected with CSF from volunteers without neurological disease; and (3) ALS group, animals inoculated with CFS from a patient with definite ALS. After surgical and infusion procedures, animals were evaluated in different motor tests (grip strength; catalepsy and open field tests). Moreover, animals’ spinal cords were histologically investigated. We observed that ALS-CSF infusion reduced grip strength and led to motor changes and reduction in the number of motor neurons and glial cells in thoracic and lumbar regions of spinal cord. However, CSF N-ALS caused reduction of nerve and glial cells in the thoracic but not in the lumbar region. Our data suggest that ALS-CSF is associated with neurodegenerative mechanisms observed in ALS pathology.