scholarly journals Random forest modelling of neuropathological features identifies microglial activation as an accurate pathological classifier of C9orf72-related amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Olivia M Rifai ◽  
James Longden ◽  
Judi O'Shaughnessy ◽  
Michael DE Sewell ◽  
Karina McDade ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Random Forest ◽  
Protein Misfolding ◽  
Microglial Activation ◽  
Rna Binding ◽  
Disease Status ◽  
Forest Modelling ◽  
Immunohistochemical Markers ◽  
Hexanucleotide Repeat ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are regarded as two ends of a pathogenetic spectrum, termed ALS-frontotemporal spectrum disorder (ALS-FTSD). However, it is currently difficult to predict where on the spectrum an individual will lie, especially for patients with C9orf72 hexanucleotide repeat expansions (HRE), a mutation associated with both ALS and FTD. It has been shown that both inflammation and protein misfolding influence aspects of ALS and ALS-FTSD disease pathogenesis, such as the manifestation or severity of motor or cognitive symptoms. Previous studies have highlighted markers which may influence C9orf72-associated disease presentation in a targeted fashion, though there has yet to be a systematic and quantitative assessment of common immunohistochemical markers to investigate the significance of these pathways in an unbiased manner. Here we report the first extensive digital pathological assessment with random forest modelling of pathological markers often used in neuropathology practice. This study profiles glial activation and protein misfolding in a cohort of deeply clinically profiled post-mortem tissue from patients with a C9orf72 HRE, who either met the criteria for a diagnosis of ALS or ALS-FTSD. We show that microglial immunohistochemical staining features, both morphological and spatial, are the best independent classifiers of disease status and that clinicopathological associations exist between microglial activation status and cognitive dysfunction in ALS-FTSD patients with C9orf72 HRE. Furthermore, we show that spatially resolved changes in FUS staining are also an accurate predictor of disease status, implying that liquid-liquid phase shift of this aggregation-prone RNA-binding protein may be important in ALS caused by a C9orf72 HRE. Our findings provide further support to the hypothesis of dysfunctional immune regulation and proteostasis in the pathogenesis of C9orf72 ALS and provide a framework for digital analysis of commonly used neuropathological stains as a tool to enrich our understanding of clinicopathological associations between cohorts.

Riluzole Exhibits No Therapeutic Efficacy on a Transgenic Rat model of Amyotrophic Lateral Sclerosis

2020 ◽  
Vol 17 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Si Chen ◽  
Qiao Liao ◽  
Ke Lu ◽  
Jinxia Zhou ◽  
Cao Huang ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Rat Model ◽  
Microglial Activation ◽  
Transgenic Rat ◽  
Intragastric Administration ◽  
Behavioral Deficits ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Transgenic Rat Model

Background: Amyotrophic lateral sclerosis (ALS) is a neurological disorder clinically characterized by motor system dysfunction, with intraneuronal accumulation of the TAR DNAbinding protein 43 (TDP-43) being a pathological hallmark. Riluzole is a primarily prescribed medicine for ALS patients, while its therapeutical efficacy appears limited. TDP-43 transgenic mice are existing animal models for mechanistic/translational research into ALS. Methods: We developed a transgenic rat model of ALS expressing a mutant human TDP-43 transgene (TDP-43M337V) and evaluated the therapeutic effect of Riluzole on this model. Relative to control, rats with TDP-43M337V expression promoted by the neurofilament heavy subunit (NEF) gene or specifically in motor neurons promoted by the choline acetyltransferase (ChAT) gene showed progressive worsening of mobility and grip strength, along with loss of motor neurons, microglial activation, and intraneuronal accumulation of TDP-43 and ubiquitin aggregations in the spinal cord. Results: Compared to vehicle control, intragastric administration of Riluzole (30 mg/kg/d) did not mitigate the behavioral deficits nor alter the neuropathologies in the transgenics. Conclusion: These findings indicate that transgenic rats recapitulate the basic neurological and neuropathological characteristics of human ALS, while Riluzole treatment can not halt the development of the behavioral and histopathological phenotypes in this new transgenic rodent model of ALS.

scholarly journals Proline/arginine dipeptide repeat polymers derail protein folding in amyotrophic lateral sclerosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Babu ◽  
Filippo Favretto ◽  
Alain Ibáñez de Opakua ◽  
Marija Rankovic ◽  
Stefan Becker ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Protein Folding ◽  
Neurodegenerative Diseases ◽  
Catalyst Activity ◽  
Coding Region ◽  
Prolyl Isomerase ◽  
X Ray Crystallography ◽  
Hexanucleotide Repeat ◽  
Lateral Sclerosis ◽  
Dipeptide Repeat

AbstractAmyotrophic lateral sclerosis and frontotemporal dementia are two neurodegenerative diseases with overlapping clinical features and the pathological hallmark of cytoplasmic deposits of misfolded proteins. The most frequent cause of familial forms of these diseases is a hexanucleotide repeat expansion in the non-coding region of the C9ORF72 gene that is translated into dipeptide repeat polymers. Here we show that proline/arginine repeat polymers derail protein folding by sequestering molecular chaperones. We demonstrate that proline/arginine repeat polymers inhibit the folding catalyst activity of PPIA, an abundant molecular chaperone and prolyl isomerase in the brain that is altered in amyotrophic lateral sclerosis. NMR spectroscopy reveals that proline/arginine repeat polymers bind to the active site of PPIA. X-ray crystallography determines the atomic structure of a proline/arginine repeat polymer in complex with the prolyl isomerase and defines the molecular basis for the specificity of disease-associated proline/arginine polymer interactions. The combined data establish a toxic mechanism that is specific for proline/arginine dipeptide repeat polymers and leads to derailed protein homeostasis in C9orf72-associated neurodegenerative diseases.

scholarly journals RBM45 Modulates the Antioxidant Response in Amyotrophic Lateral Sclerosis through Interactions with KEAP1

2015 ◽  
Vol 35 (14) ◽  
pp. 2385-2399 ◽  
Author(s):  
Nadine Bakkar ◽  
Arianna Kousari ◽  
Tina Kovalik ◽  
Yang Li ◽  
Robert Bowser
Keyword(s):  
Oxidative Stress ◽  
Spinal Cord ◽  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Antioxidant Response ◽  
Cytoplasmic Inclusions ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the selective loss of motor neurons. Various factors contribute to the disease, including RNA binding protein dysregulation and oxidative stress, but their exact role in pathogenic mechanisms remains unclear. We have recently linked another RNA binding protein, RBM45, to ALS via increased levels of protein in the cerebrospinal fluid of ALS patients and its localization to cytoplasmic inclusions in ALS motor neurons. Here we show RBM45 nuclear exit in ALS spinal cord motor neurons compared to controls, a phenotype recapitulatedin vitroin motor neurons treated with oxidative stressors. We find that RBM45 binds and stabilizes KEAP1, the inhibitor of the antioxidant response transcription factor NRF2. ALS lumbar spinal cord lysates similarly show increased cytoplasmic binding of KEAP1 and RBM45. Binding of RBM45 to KEAP1 impedes the protective antioxidant response, thus contributing to oxidative stress-induced cellular toxicity. Our findings thus describe a novel link between a mislocalized RNA binding protein implicated in ALS (RBM45) and dysregulation of the neuroprotective antioxidant response seen in the disease.

scholarly journals TDP-43 mutations link Amyotrophic Lateral Sclerosis with R-loop homeostasis and R loop-mediated DNA damage

PLoS Genetics ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. e1009260
Author(s):  
Marta Giannini ◽  
Aleix Bayona-Feliu ◽  
Daisy Sproviero ◽  
Sonia I. Barroso ◽  
Cristina Cereda ◽  
...  
Keyword(s):  
Dna Damage ◽  
Amyotrophic Lateral Sclerosis ◽  
Rna Binding ◽  
Neurodegenerative Disorder ◽  
Genome Instability ◽  
Neuronal Model ◽  
Dna Breaks ◽  
Dna And Rna ◽  
Double Strand Dna Breaks ◽  
Lateral Sclerosis

TDP-43 is a DNA and RNA binding protein involved in RNA processing and with structural resemblance to heterogeneous ribonucleoproteins (hnRNPs), whose depletion sensitizes neurons to double strand DNA breaks (DSBs). Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder, in which 97% of patients are familial and sporadic cases associated with TDP-43 proteinopathies and conditions clearing TDP-43 from the nucleus, but we know little about the molecular basis of the disease. After showing with the non-neuronal model of HeLa cells that TDP-43 depletion increases R loops and associated genome instability, we prove that mislocalization of mutated TDP-43 (A382T) in transfected neuronal SH-SY5Y and lymphoblastoid cell lines (LCLs) from an ALS patient cause R-loop accumulation, R loop-dependent increased DSBs and Fanconi Anemia repair centers. These results uncover a new role of TDP-43 in the control of co-transcriptional R loops and the maintenance of genome integrity by preventing harmful R-loop accumulation. Our findings thus link TDP-43 pathology to increased R loops and R loop-mediated DNA damage opening the possibility that R-loop modulation in TDP-43-defective cells might help develop ALS therapies.

scholarly journals Concomitant gain and loss of function pathomechanisms in C9ORF72 amyotrophic lateral sclerosis

2021 ◽  
Vol 4 (4) ◽  
pp. e202000764
Author(s):  
Arun Pal ◽  
Benedikt Kretner ◽  
Masin Abo-Rady ◽  
Hannes Glaβ ◽  
Banaja P Dash ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Loss Of Function ◽  
Dna Double Strand Breaks ◽  
Hexanucleotide Repeat ◽  
Rna Foci ◽  
Repeat Expansions ◽  
Organelle Motility ◽  
Trafficking Defects ◽  
Induced Pluripotent ◽  
Lateral Sclerosis

Intronic hexanucleotide repeat expansions (HREs) in C9ORF72 are the most frequent genetic cause of amyotrophic lateral sclerosis, a devastating, incurable motoneuron (MN) disease. The mechanism by which HREs trigger pathogenesis remains elusive. The discovery of repeat-associated non-ATG (RAN) translation of dipeptide repeat proteins (DPRs) from HREs along with reduced exonic C9ORF72 expression suggests gain of toxic functions (GOFs) through DPRs versus loss of C9ORF72 functions (LOFs). Through multiparametric high-content (HC) live profiling in spinal MNs from induced pluripotent stem cells and comparison to mutant FUS and TDP43, we show that HRE C9ORF72 caused a distinct, later spatiotemporal appearance of mainly proximal axonal organelle motility deficits concomitant to augmented DNA double-strand breaks (DSBs), RNA foci, DPRs, and apoptosis. We show that both GOFs and LOFs were necessary to yield the overall C9ORF72 pathology. Increased RNA foci and DPRs concurred with onset of axon trafficking defects, DSBs, and cell death, although DSB induction itself did not phenocopy C9ORF72 mutants. Interestingly, the majority of LOF-specific DEGs were shared with HRE-mediated GOF DEGs. Finally, C9ORF72 LOF was sufficient—albeit to a smaller extent—to induce premature distal axonal trafficking deficits and increased DSBs.

scholarly journals Motor neuron translatome reveals deregulation of SYNGR4 and PLEKHB1 in mutant TDP-43 amyotrophic lateral sclerosis models

2020 ◽  
Vol 29 (16) ◽  
pp. 2647-2661 ◽  
Author(s):  
Rita F Marques ◽  
Jan B Engler ◽  
Katrin Küchler ◽  
Ross A Jones ◽  
Thomas Lingner ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Symptom Onset ◽  
Rna Binding ◽  
Affinity Purification ◽  
Disease Onset ◽  
Motor Symptom ◽  
Pathological Feature ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is an incurable neurological disease with progressive loss of motor neuron (MN) function in the brain and spinal cord. Mutations in TARDBP, encoding the RNA-binding protein TDP-43, are one cause of ALS, and TDP-43 mislocalization in MNs is a key pathological feature of >95% of ALS cases. While numerous studies support altered RNA regulation by TDP-43 as a major cause of disease, specific changes within MNs that trigger disease onset remain unclear. Here, we combined translating ribosome affinity purification (TRAP) with RNA sequencing to identify molecular changes in spinal MNs of TDP-43–driven ALS at motor symptom onset. By comparing the MN translatome of hTDP-43A315T mice to littermate controls and to mice expressing wild type hTDP-43, we identified hundreds of mRNAs that were selectively up- or downregulated in MNs. We validated the deregulated candidates Tex26, Syngr4, and Plekhb1 mRNAs in an independent TRAP experiment. Moreover, by quantitative immunostaining of spinal cord MNs, we found corresponding protein level changes for SYNGR4 and PLEKHB1. We also observed these changes in spinal MNs of an independent ALS mouse model caused by a different patient mutant allele of TDP-43, suggesting that they are general features of TDP-43-driven ALS. Thus, we identified SYNGR4 and PLEKHB1 to be deregulated in MNs at motor symptom onset in TDP-43-driven ALS models. This spatial and temporal pattern suggests that these proteins could be functionally important for driving the transition to the symptomatic phase of the disease.

scholarly journals The Impact of ALS-Associated Genes hnRNPA1, MATR3, VCP and UBQLN2 on the Severity of TDP-43 Aggregation

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1791
Author(s):  
Ana Bajc Česnik ◽  
Helena Motaln ◽  
Boris Rogelj
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Rna Binding ◽  
Neurodegenerative Disorder ◽  
Low Complexity ◽  
Wild Type ◽  
Disease Heterogeneity ◽  
Cytoplasmic Inclusions ◽  
The Impact ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disorder, characterized by cytoplasmic inclusions of RNA-binding protein TDP-43. Despite decades of research and identification of more than 50 genes associated with amyotrophic lateral sclerosis (ALS), the cause of TDP-43 translocation from the nucleus and its aggregation in the cytoplasm still remains unknown. Our study addressed the impact of selected ALS-associated genes on TDP-43 aggregation behavior in wild-type and aggregation prone TDP-43 in vitro cell models. These were developed by deleting TDP-43 nuclear localization signal and stepwise shortening its low-complexity region. The SH-SY5Y cells were co-transfected with the constructs of aggregation-prone TDP-43 and wild-type or mutant ALS-associated genes hnRNPA1, MATR3, VCP or UBQLN2. The investigated genes displayed a unique impact on TDP-43 aggregation, generating distinct types of cytoplasmic inclusions, similar to those already described as resembling prion strains, which could represent the basis for neurodegenerative disease heterogeneity.

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