scholarly journals Amyotrophic lateral sclerosis associated mislocalisation of TDP-43 to the cytoplasm causes cortical hyperexcitability and reduced excitatory neurotransmission in the motor cortex

2020 ◽  
Author(s):  
MS Dyer ◽  
KE Lewis ◽  
AK Walker ◽  
TC Dickson ◽  
A Woodhouse ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Mouse Models ◽  
Rna Binding ◽  
Binding Protein ◽  
Synaptic Function ◽  
Nuclear Localization Sequence ◽  
Mechanisms Of Toxicity ◽  
Cortical Hyperexcitability ◽  
Lateral Sclerosis

AbstractAmyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disease pathologically characterised by mislocalisation of the RNA binding protein TAR-DNA binding protein 43 (TDP-43) from the nucleus to the cytoplasm. Changes to neuronal excitability and synapse dysfunction in the motor cortex are early pathological changes occurring in people with ALS and mouse models of disease. To investigate the effect of mislocalized TDP-43 on the function of motor cortex neurons we utilised mouse models that express either human wild-type (TDP-43WT) or nuclear localization sequence-deficient TDP-43 (TDP-43ΔNLS) on an inducible promoter that is restricted to the forebrain. Pathophysiology was investigated through immunohistochemistry and whole-cell patch-clamp electrophysiology. Thirty days expression TDP-43ΔNLS in adult mice (60 days of age) does not cause any changes in the number of NeuN positive nor CTIP2 positive neurons in the motor cortex. However at this time-point the expression of TDP-43ΔNLS drives intrinsic hyperexcitability in layer V excitatory neurons of the motor cortex. This hyperexcitability occurs concomitantly with a decrease in excitatory synaptic input to these cells. This pathophysiology is not present when TDP-43WT expression is driven, demonstrating that the localisation of TDP-43 to the cytoplasm is crucial for the altered excitability phenotype. This study has important implications for the mechanisms of toxicity of one of the most notorious proteins linked to ALS, TDP-43. We provide the first evidence that TDP-43 mislocalization causes aberrant synaptic function and a hyperexcitability phenotype in the motor cortex, linking some of the earliest dysfunctions to arise in people with ALS to mislocalisation of TDP-43.

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 Nuclear depletion of RNA binding protein ELAVL3 (HuC) in sporadic and familial amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Sandra Diaz-Garcia ◽  
Vivian I. Ko ◽  
Sonia Vazquez-Sanchez ◽  
Ruth Chia ◽  
Olubankole Aladesuyi Arogundade ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Loss Of Function ◽  
Cryptic Exon ◽  
Protein Levels ◽  
Sporadic Als ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive fatal neurodegenerative disease caused by loss of motor neurons and characterized neuropathologically in almost all cases by nuclear depletion and cytoplasmic aggregation of TDP-43, a nuclear RNA binding protein (RBP). We identified ELAVL3 as one of the most downregulated genes in our transcriptome profiles of laser captured microdissection of motor neurons from sporadic ALS nervous systems and the top dysregulated RBPs. Neuropathological characterizations showed ELAVL3 nuclear depletion in a great percentage of remnant motor neurons, sometimes accompanied by cytoplasmic accumulations. These abnormalities were common in sporadic cases with and without intermediate expansions in ATXN2 and familial cases carrying mutations in C9orf72 and SOD1. Depletion of ELAVL3 occurred at both the RNA and protein levels and a short protein isoform was identified but it is not related to a TDP-43-dependent cryptic exon in intron 3. Strikingly, ELAVL3 abnormalities were more frequent than TDP-43 abnormalities and occurred in motor neurons still with normal nuclear TDP-43 present, but all neurons with abnormal TDP-43 also had abnormal ELAVL3. In a neuron-like cell culture model using SH-SY5Y cells, ELAVL3 mislocalization occurred weeks before TDP-43 abnormalities were seen. We interrogated genetic databases but did not identify association of ELAVL3 genetic structure associated with ALS. Taken together, these findings suggest that ELAVL3 is an important RBP in ALS pathogenesis acquired early and the neuropathological data suggest it is involved by loss of function rather than cytoplasmic toxicity.

scholarly journals Characteristic Features of FUS Inclusions in Spinal Motor Neurons of Sporadic Amyotrophic Lateral Sclerosis

2020 ◽  
Vol 79 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Kensuke Ikenaka ◽  
Shinsuke Ishigaki ◽  
Yohei Iguchi ◽  
Kaori Kawai ◽  
Yusuke Fujioka ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Rna Binding ◽  
Binding Protein ◽  
Specific Antigen ◽  
Antigen Retrieval ◽  
Technical Limitation ◽  
Cytoplasmic Inclusions ◽  
Sporadic Als ◽  
Lateral Sclerosis

Abstract Alterations of RNA metabolism caused by mutations in RNA-binding protein genes, such as transactivating DNA-binding protein-43 (TDP-43) and fused in sarcoma (FUS), have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Unlike the accumulation of TDP43, which is accepted as a pathological hall mark of sporadic ALS (sALS), FUS pathology in sALS is still under debate. Although immunoreactive inclusions of FUS have been detected in sALS patients previously, the technical limitation of signal detection, including the necessity of specific antigen retrieval, restricts our understanding of FUS-associated ALS pathology. In this study, we applied a novel detection method using a conventional antigen retrieval technique with Sudan Black B treatment to identify FUS-positive inclusions in sALS patients. We classified pathological motor neurons into 5 different categories according to the different aggregation characteristics of FUS and TDP-43. Although the granular type was more dominant for inclusions with TDP-43, the skein-like type was more often observed in FUS-positive inclusions, suggesting that these 2 proteins undergo independent aggregation processes. Moreover, neurons harboring FUS-positive inclusions demonstrated substantially reduced expression levels of dynactin-1, a retrograde motor protein, indicating that perturbation of nucleocytoplasmic transport is associated with the formation of cytoplasmic inclusions of FUS in sALS.

scholarly journals Cortical interneuron-mediated inhibition delays the onset of amyotrophic lateral sclerosis

Brain ◽  
2020 ◽  
Vol 143 (3) ◽  
pp. 800-810 ◽  
Author(s):  
C Sahara Khademullah ◽  
Afif J Aqrabawi ◽  
Kara M Place ◽  
Zahra Dargaei ◽  
Xinyi Liang ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Intracortical Inhibition ◽  
Motor Deficits ◽  
Cortical Interneuron ◽  
Neuronal Populations ◽  
Cortical Hyperexcitability ◽  
Symptom Progression ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis is a fatal disease resulting from motor neuron degeneration in the cortex and spinal cord. Cortical hyperexcitability is a hallmark feature of amyotrophic lateral sclerosis and is accompanied by decreased intracortical inhibition. Using electrophysiological patch-clamp recordings, we revealed parvalbumin interneurons to be hypoactive in the late pre-symptomatic SOD1*G93A mouse model of amyotrophic lateral sclerosis. We discovered that using adeno-associated virus-mediated delivery of chemogenetic technology targeted to increase the activity of the interneurons within layer 5 of the primary motor cortex, we were able to rescue intracortical inhibition and reduce pyramidal neuron hyperexcitability. Increasing the activity of interneurons in the layer 5 of the primary motor cortex was effective in delaying the onset of amyotrophic lateral sclerosis-associated motor deficits, slowing symptom progression, preserving neuronal populations, and increasing the lifespan of SOD1*G93A mice. Taken together, this study provides novel insights into the pathogenesis and treatment of amyotrophic lateral sclerosis.

scholarly journals A matter of balance

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Aaron D Gitler ◽  
John D Fryer
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Frontotemporal Dementia ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Lateral Sclerosis

New analyses shift the view that some forms of amyotrophic lateral sclerosis and frontotemporal dementia are due to defects in a single RNA-binding protein.

scholarly journals Revealing the Proteome of Motor Cortex Derived Extracellular Vesicles Isolated from Amyotrophic Lateral Sclerosis Human Postmortem Tissues

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1709
Author(s):  
Natasha Vassileff ◽  
Laura J. Vella ◽  
Harinda Rajapaksha ◽  
Mitch Shambrook ◽  
Amirmohammad Nasiri Kenari ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Extracellular Vesicles ◽  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mass Spectrometry Analysis ◽  
Spectrometry Analysis ◽  
Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by the deposition of misfolded proteins in the motor cortex and motor neurons. Although a multitude of ALS-associated mutated proteins have been identified, several have been linked to small extracellular vesicles such as exosomes involved in cell−cell communication. This study aims to determine the proteome of extracellular vesicles isolated from the motor cortex of ALS subjects and to identify novel ALS-associated deregulated proteins. Motor cortex extracellular vesicles (MCEVs) were isolated from human postmortem ALS (n = 10) and neurological control (NC, n = 5) motor cortex brain tissues and the MCEVs protein content subsequently underwent mass spectrometry analysis, allowing for a panel of ALS-associated proteins to be identified. This panel consists of 16 statistically significant differentially packaged proteins identified in the ALS MCEVs. This includes several upregulated RNA-binding proteins which were determined through pathway analysis to be associated with stress granule dynamics. The identification of these RNA-binding proteins in the ALS MCEVs suggests there may be a relationship between ALS-associated stress granules and ALS MCEV packaging, highlighting a potential role for small extracellular vesicles such as exosomes in the pathogenesis of ALS and as potential peripheral biomarkers for ALS.

scholarly journals Nuclear depletion of RNA-binding protein ELAVL3 (HuC) in sporadic and familial amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Sandra Diaz-Garcia ◽  
Vivian I. Ko ◽  
Sonia Vazquez-Sanchez ◽  
Ruth Chia ◽  
Olubankole Aladesuyi Arogundade ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Loss Of Function ◽  
Cryptic Exon ◽  
Protein Levels ◽  
Sporadic Als ◽  
Lateral Sclerosis

AbstractAmyotrophic lateral sclerosis is a progressive fatal neurodegenerative disease caused by loss of motor neurons and characterized neuropathologically in almost all cases by nuclear depletion and cytoplasmic aggregation of TDP-43, a nuclear RNA-binding protein (RBP). We identified ELAVL3 as one of the most downregulated genes in our transcriptome profiles of laser captured microdissection of motor neurons from sporadic ALS nervous systems and the most dysregulated of all RBPs. Neuropathological characterizations showed ELAVL3 nuclear depletion in a great percentage of remnant motor neurons, sometimes accompanied by cytoplasmic accumulations. These abnormalities were common in sporadic cases with and without intermediate expansions in ATXN2 and familial cases carrying mutations in C9orf72 and SOD1. Depletion of ELAVL3 occurred at both the RNA and protein levels and a short protein isoform was identified, but it is not related to a TDP-43-dependent cryptic exon in intron 3. Strikingly, ELAVL3 abnormalities were more frequent than TDP-43 abnormalities and occurred in motor neurons still with normal nuclear TDP-43 present, but all neurons with abnormal TDP-43 also had abnormal ELAVL3. In a neuron-like cell culture model using SH-SY5Y cells, ELAVL3 mislocalization occurred weeks before TDP-43 abnormalities were seen. We interrogated genetic databases, but did not identify association of ELAVL3 genetic structure with ALS. Taken together, these findings suggest that ELAVL3 is an important RBP in ALS pathogenesis acquired early and the neuropathological data suggest that it is involved by loss of function rather than cytoplasmic toxicity.

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