scholarly journals C9orf72-derived poly-GA DPRs undergo endocytic uptake in iNPC-derived astrocytes and spread to motor neurons

2021 ◽  
Author(s):  
Paolo M. Marchi ◽  
Lara Marrone ◽  
Laurent Brasseur ◽  
Luc Bousset ◽  
Christopher P. Webster ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Disease Spread ◽  
C9orf72 Gene ◽  
Cell Propagation ◽  
Β Sheet ◽  
Lateral Sclerosis ◽  
Dipeptide Repeat ◽  
Axonal Swellings

Dipeptide repeat proteins (DPRs) are aggregation-prone polypeptides encoded by the pathogenic G4C2 repeat expansion in the C9orf72 gene, the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). In this study, we focus on the role of poly-GA DPRs in disease spread. We demonstrate that recombinant poly-GA oligomers can directly convert into solid-like aggregates and form characteristic β-sheet fibrils in vitro. To dissect the process of cell-to-cell DPR transmission, we closely follow the fate of poly-GA DPRs in either their oligomeric or fibrillized form after administration in the cell culture medium. We observe that poly-GA DPRs are taken up via dynamin-dependent and -independent endocytosis, eventually converging at the lysosomal compartment and leading to axonal swellings in neurons. We then use a co-culture system to demonstrate astrocyte-to-motor neuron DPR propagation, showing that astrocytes may internalise and release aberrant peptides in disease pathogenesis. Overall, our results shed light on the mechanisms of poly-GA cellular uptake and cell-to-cell propagation, suggesting lysosomal impairment as a possible feature underlying the cellular pathogenicity of these DPR species.

Phase separation and toxicity of C9orf72 poly(PR) depends on alternate distribution of arginine

2021 ◽  
Vol 220 (11) ◽  
Author(s):  
Chen Chen ◽  
Yoshiaki Yamanaka ◽  
Koji Ueda ◽  
Peiying Li ◽  
Tamami Miyagi ◽  
...  
Keyword(s):  
Phase Separation ◽  
Charge Distribution ◽  
Protein Interactions ◽  
Protein Protein Interactions ◽  
C9orf72 Gene ◽  
And Diffusion ◽  
Lateral Sclerosis ◽  
Dipeptide Repeat ◽  
Liquid Liquid Phase Separation

Arg (R)-rich dipeptide repeat proteins (DPRs; poly(PR): Pro-Arg and poly(GR): Gly-Arg), encoded by a hexanucleotide expansion in the C9ORF72 gene, induce neurodegeneration in amyotrophic lateral sclerosis (ALS). Although R-rich DPRs undergo liquid–liquid phase separation (LLPS), which affects multiple biological processes, mechanisms underlying LLPS of DPRs remain elusive. Here, using in silico, in vitro, and in cellulo methods, we determined that the distribution of charged Arg residues regulates the complex coacervation with anionic peptides and nucleic acids. Proteomic analyses revealed that alternate Arg distribution in poly(PR) facilitates entrapment of proteins with acidic motifs via LLPS. Transcription, translation, and diffusion of nucleolar nucleophosmin (NPM1) were impaired by poly(PR) with an alternate charge distribution but not by poly(PR) variants with a consecutive charge distribution. We propose that the pathogenicity of R-rich DPRs is mediated by disturbance of proteins through entrapment in the phase-separated droplets via sequence-controlled multivalent protein–protein interactions.

scholarly journals Systematic elucidation of neuron-astrocyte interaction in models of amyotrophic lateral sclerosis using multi-modal integrated bioinformatics workflow

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Vartika Mishra ◽  
Diane B. Re ◽  
Virginia Le Verche ◽  
Mariano J. Alvarez ◽  
Alessandro Vasciaveo ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Death Receptor ◽  
Cell Interaction ◽  
Type Motor ◽  
Cellular Compartments ◽  
Death Receptor 6 ◽  
Lateral Sclerosis

Abstract Cell-to-cell communications are critical determinants of pathophysiological phenotypes, but methodologies for their systematic elucidation are lacking. Herein, we propose an approach for the Systematic Elucidation and Assessment of Regulatory Cell-to-cell Interaction Networks (SEARCHIN) to identify ligand-mediated interactions between distinct cellular compartments. To test this approach, we selected a model of amyotrophic lateral sclerosis (ALS), in which astrocytes expressing mutant superoxide dismutase-1 (mutSOD1) kill wild-type motor neurons (MNs) by an unknown mechanism. Our integrative analysis that combines proteomics and regulatory network analysis infers the interaction between astrocyte-released amyloid precursor protein (APP) and death receptor-6 (DR6) on MNs as the top predicted ligand-receptor pair. The inferred deleterious role of APP and DR6 is confirmed in vitro in models of ALS. Moreover, the DR6 knockdown in MNs of transgenic mutSOD1 mice attenuates the ALS-like phenotype. Our results support the usefulness of integrative, systems biology approach to gain insights into complex neurobiological disease processes as in ALS and posit that the proposed methodology is not restricted to this biological context and could be used in a variety of other non-cell-autonomous communication mechanisms.

Overexpression of mutated Cu,Zn-SOD in neuroblastoma cells results in cytoskeletal change

2005 ◽  
Vol 288 (2) ◽  
pp. C253-C259 ◽  
Author(s):  
Rina Takamiya ◽  
Motoko Takahashi ◽  
Yong Seek Park ◽  
Yoshie Tawara ◽  
Noriko Fujiwara ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Neuroblastoma Cells ◽  
Two Dimensional Gel Electrophoresis ◽  
Progressive Degeneration ◽  
Incubation Experiments ◽  
Lower Reactivity ◽  
Lateral Sclerosis ◽  
Human Wild Type

Amyotrophic lateral sclerosis (ALS) involves the progressive degeneration of motor neurons in the spinal cord and the motor cortex. It has been shown that 15–20% of patients with familial ALS (FALS) have defects in the Sod1 gene, which encodes Cu,Zn-superoxide dismutase (SOD). To elucidate the pathological role of mutated Cu,Zn-SOD, we examined the issue of whether mutated Cu,Zn-SOD affects the cell cycle. Mouse neuroblastoma Neuro-2a cells were transfected with human wild-type or mutated (G37R, G93A) Cu,Zn-SOD. Mutated, Cu,Zn-SOD-transfected cells exhibited marked retardation in cell growth and G2/M arrest. They also displayed lower reactivity to phalloidin, indicating that the cytoskeleton was disrupted. Immunoprecipitation, two-dimensional gel electrophoresis, and Western blot analysis indicated that mutated Cu,Zn-SOD associates with actin. Similar results were obtained by in vitro incubation experiments with purified actin and mutated Cu,Zn-SOD (G93A). These results suggest that mutated Cu,Zn-SOD in FALS causes cytoskeletal changes by associating with actin, which subsequently causes G2/M arrest and growth retardation.

scholarly journals C9orf72-generated poly-GR and poly-PR do not directly interfere with nucleocytoplasmic transport

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Joni Vanneste ◽  
Thomas Vercruysse ◽  
Steven Boeynaems ◽  
Adria Sicart ◽  
Philip Van Damme ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Hela Cells ◽  
Nuclear Import ◽  
Nucleocytoplasmic Transport ◽  
Repeat Expansions ◽  
Import And Export ◽  
Lateral Sclerosis ◽  
Dipeptide Repeat

Abstract Repeat expansions in the C9orf72 gene cause amyotrophic lateral sclerosis and frontotemporal dementia characterized by dipeptide-repeat protein (DPR) inclusions. The toxicity associated with two of these DPRs, poly-GR and poly-PR, has been associated with nucleocytoplasmic transport. To investigate the causal role of poly-GR or poly-PR on active nucleocytoplasmic transport, we measured nuclear import and export in poly-GR or poly-PR expressing Hela cells, neuronal-like SH-SY5Y cells and iPSC-derived motor neurons. Our data strongly indicate that poly-GR and poly-PR do not directly impede active nucleocytoplasmic transport.

scholarly journals Haploinsufficiency of the TDP43 ubiquitin E3 ligase RNF220 leads to ALS-like motor neuron defects in the mouse

2021 ◽  
Author(s):  
Pengcheng Ma ◽  
Yuwei Li ◽  
Huishan Wang ◽  
Bingyu Mao
Keyword(s):  
Motor Neurons ◽  
Regulatory Protein ◽  
E3 Ligase ◽  
Subcellular Location ◽  
Spinal Motor Neurons ◽  
Ubiquitin E3 Ligase ◽  
Lateral Sclerosis

Abstract TDP43 pathology is seen in a large majority of amyotrophic lateral sclerosis (ALS) cases, suggesting a central pathogenic role of this regulatory protein. Clarifying the molecular mechanism controlling TDP43 stability and subcellular location might provide important insights into ALS therapy. The ubiquitin E3 ligase RNF220 is involved in different neural developmental processes through various molecular targets in the mouse. Here, we report that the RNF220+/- mice showed progressively decreasing mobility to different extents, some of which developed typical ALS pathological characteristics in spinal motor neurons, including TDP43 cytoplasmic accumulation, atrocytosis, muscle denervation, and atrophy. Mechanistically, RNF220 interacts with TDP43 in vitro and in vivo and promotes its polyubiquitination and proteasomal degradation. In conclusion, we propose that RNF220 might be a modifier of TDP43 function in vivo and contribute to TDP43 pathology in neurodegenerative disease like ALS.

scholarly journals Cortical and Striatal Electroencephalograms and Apomorphine Effects in the FUS Mouse Model of Amyotrophic Lateral Sclerosis

2021 ◽  
pp. 1-15
Author(s):  
Vasily Vorobyov ◽  
Alexander Deev ◽  
Frank Sengpiel ◽  
Vladimir Nebogatikov ◽  
Aleksey A. Ustyugov
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Cortical Neurons ◽  
Primary Motor Cortex ◽  
Beta Activity ◽  
Systemic Injection ◽  
Eeg Spectra ◽  
Electroencephalogram Eeg ◽  
Lateral Sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is characterized by degeneration of motor neurons resulting in muscle atrophy. In contrast to the lower motor neurons, the role of upper (cortical) neurons in ALS is yet unclear. Maturation of locomotor networks is supported by dopaminergic (DA) projections from substantia nigra to the spinal cord and striatum. Objective: To examine the contribution of DA mediation in the striatum-cortex networks in ALS progression. Methods: We studied electroencephalogram (EEG) from striatal putamen (Pt) and primary motor cortex (M1) in ΔFUS(1–359)-transgenic (Tg) mice, a model of ALS. EEG from M1 and Pt were recorded in freely moving young (2-month-old) and older (5-month-old) Tg and non-transgenic (nTg) mice. EEG spectra were analyzed for 30 min before and for 60 min after systemic injection of a DA mimetic, apomorphine (APO), and saline. Results: In young Tg versus nTg mice, baseline EEG spectra in M1 were comparable, whereas in Pt, beta activity in Tg mice was enhanced. In older Tg versus nTg mice, beta dominated in EEG from both M1 and Pt, whereas theta and delta 2 activities were reduced. In younger Tg versus nTg mice, APO increased theta and decreased beta 2 predominantly in M1. In older mice, APO effects in these frequency bands were inversed and accompanied by enhanced delta 2 and attenuated alpha in Tg versus nTg mice. Conclusion: We suggest that revealed EEG modifications in ΔFUS(1–359)-transgenic mice are associated with early alterations in the striatum-cortex interrelations and DA transmission followed by adaptive intracerebral transformations.

scholarly journals RNA Is a Double-Edged Sword in ALS Pathogenesis

2021 ◽  
Vol 15 ◽  
Author(s):  
Benjamin L. Zaepfel ◽  
Jeffrey D. Rothstein
Keyword(s):  
Motor Neurons ◽  
Cortical Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Metabolism ◽  
Small Subset ◽  
Toxic Rna ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease that affects upper and lower motor neurons. Familial ALS accounts for a small subset of cases (<10–15%) and is caused by dominant mutations in one of more than 10 known genes. Multiple genes have been causally or pathologically linked to both ALS and frontotemporal dementia (FTD). Many of these genes encode RNA-binding proteins, so the role of dysregulated RNA metabolism in neurodegeneration is being actively investigated. In addition to defects in RNA metabolism, recent studies provide emerging evidence into how RNA itself can contribute to the degeneration of both motor and cortical neurons. In this review, we discuss the roles of altered RNA metabolism and RNA-mediated toxicity in the context of TARDBP, FUS, and C9ORF72 mutations. Specifically, we focus on recent studies that describe toxic RNA as the potential initiator of disease, disease-associated defects in specific RNA metabolism pathways, as well as how RNA-based approaches can be used as potential therapies. Altogether, we highlight the importance of RNA-based investigations into the molecular progression of ALS, as well as the need for RNA-dependent structural studies of disease-linked RNA-binding proteins to identify clear therapeutic targets.

scholarly journals Gamma motor neurons survive and exacerbate alpha motor neuron degeneration in ALS

2016 ◽  
Vol 113 (51) ◽  
pp. E8316-E8325 ◽  
Author(s):  
Melanie Lalancette-Hebert ◽  
Aarti Sharma ◽  
Alexander K. Lyashchenko ◽  
Neil A. Shneider
Keyword(s):  
Motor Neuron ◽  
Mouse Models ◽  
Motor Neurons ◽  
Muscle Spindles ◽  
Excitatory Input ◽  
Synaptic Excitation ◽  
Fused In Sarcoma ◽  
Alpha Motor Neuron ◽  
Lateral Sclerosis

The molecular and cellular basis of selective motor neuron (MN) vulnerability in amyotrophic lateral sclerosis (ALS) is not known. In genetically distinct mouse models of familial ALS expressing mutant superoxide dismutase-1 (SOD1), TAR DNA-binding protein 43 (TDP-43), and fused in sarcoma (FUS), we demonstrate selective degeneration of alpha MNs (α-MNs) and complete sparing of gamma MNs (γ-MNs), which selectively innervate muscle spindles. Resistant γ-MNs are distinct from vulnerable α-MNs in that they lack synaptic contacts from primary afferent (IA) fibers. Elimination of these synapses protects α-MNs in the SOD1 mutant, implicating this excitatory input in MN degeneration. Moreover, reduced IAactivation by targeted reduction of γ-MNs in SOD1G93Amutants delays symptom onset and prolongs lifespan, demonstrating a pathogenic role of surviving γ-MNs in ALS. This study establishes the resistance of γ-MNs as a general feature of ALS mouse models and demonstrates that synaptic excitation of MNs within a complex circuit is an important determinant of relative vulnerability in ALS.

Exploring Aromatic Medicinal Compounds for the Treatment of Amyotrophic Lateral Sclerosis

2021 ◽  
Vol 16 (10) ◽  
pp. 1934578X2110308
Author(s):  
Fahad Hassan Shah ◽  
Song Ja Kim
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Major Gene ◽  
Dna Binding Protein ◽  
Chemical Affinity ◽  
Drug Candidates ◽  
Medicinal Compounds ◽  
Candidate Drug ◽  
Lateral Sclerosis

Purpose: Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative condition, in which motor neurons start to degenerate due to the accumulation of protein aggregates in the neuron cytoplasm. The formation of aggregates causes neurotoxicity, facilitated by the N-terminal domain (NTD) of the transactive response DNA-binding protein-43 (TDP-43). Therapies used to treat ALS manage secondary symptoms, but do not stop the activity of the rogue NTD domain of TDP-43. Therefore, new drug candidates should be designed to deal efficiently with this disease by inhibiting the domains involved in the development of ALS. This study determined the chemical affinity of aromatic medicinal compounds with NTD. Screening of 1323 medicinal compounds was conducted with PYRX 0.9 software against NTD. Compounds obtained from this analysis were further used to predict absorption, distribution, metabolism, excretion, and toxic (ADMET) properties and their effect on major gene targets of ALS. Results: From 1300 + compounds, acetovanillone showed binding affinity for NTD and had good ADMET and drug likeness attributes. This compound reduced the expression of CXCL2, NOP56, and SOD1 genes implicated in ALS pathogenesis. Conclusion: These results concluded that acetovanillone is a candidate drug for in vitro and clinical studies into the exploitation of drugs within ALS therapeutics.

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