Neuronal Activity-Dependent Gene Dysregulation inC9orf72i3Neuronal Models of ALS/FTD Pathogenesis
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ABSTRACT:
PROVIDER: PRJNA1152951 | ENA |
REPOSITORIES: ENA
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Project description:The GGGGCC nucleotide repeat expansion (NRE) mutation in the C9orf72 (C9) gene is the most common cause of ALS and FTD. Neuronal activity plays an essential role in shaping biological processes within both healthy and neurodegenerative disease scenarios. Here, we show that at baseline conditions, C9-NRE iPSC-cortical neurons display aberrations in several pathways, including synaptic signaling and transcriptional machinery, potentially priming diseased neurons for an altered response to neuronal stimulation. Indeed, exposure to two pathophysiologically relevant stimulation modes, prolonged membrane depolarization, or a blockade of K+ channels, followed by RNA sequencing, induces a temporally divergent activity-dependent transcriptome of C9-NRE cortical neurons compared to healthy controls. These findings reveal the impact of neuronal activity on the ALS/FTD-associated transcriptome and may reveal pathways necessary for conferring neuronal resilience or degeneration.
2024-12-31 | GSE275765 | GEO
Project description:We report a conserved transcriptomic signature of reduced fatty acid and lipid metabolism gene expression in human post-mortem ALS spinal cord and a Drosophila model of the most common genetic cause of FTD/ALS, a repeat expansion in C9orf72. To investigate lipid alterations, we performed lipidomics on C9FTD/ALS iPSC-neurons and post-mortem FTLD brain tissue. This revealed a common and specific reduction in phospholipid species containing polyunsaturated fatty acids (PUFAs). To determine whether this PUFA deficit contributes to neurodegeneration, we fed C9FTD/ALS flies PUFAs, which yielded a modest increase in survival. However, increasing PUFA levels specifically in neurons of the C9orf72 flies, by overexpressing fatty acid desaturase enzymes, led to a substantial extension of lifespan. Neuronal overexpression of fatty acid desaturases also suppressed stressor induced neuronal death in C9FTD/ALS patient iPSC-neurons. These data implicate neuronal fatty acid saturation in the pathogenesis of FTD/ALS and suggest that interventions to increase PUFA levels specifically within neurons will be beneficial.
2024-11-15 | GSE255099 | GEO
Project description:Recently, we identified missense mutations in CCNF that are causative of familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). CCNF encodes for cyclin F, a substrate recognition component of an E3-ubiquitin ligase. Mutations in CCNF directly implicates disruption in the ubiquitin-proteasome system in the pathogenesis of ALS/FTD. In this study we used an unbiased proteomic screening workflow using the proximity-based ligation method, BioID, to identify putative interaction partners of cyclin F. In doing so, we found over 100 putative interaction partners of cyclin F. Notably, we demonstrated that cyclin F closely associates with a number of essential paraspeckle proteins, which are stress-responsive proteins that have recently been implicated in ALS pathogenesis. We further demonstrate that SCFcyclin F mediates the direct ubiquitylation and subsequent proteasomal degradation of RBM14, a core component of the paraspeckle complex. This degradation is defective when cyclin F carries an ALS/FTD-causing mutation, leading to RBM14 accumulation in primary neurons upon proteasome inhibition. Additionally, analysis of ALS patient post-mortem tissue revealed that RBM14 levels were significantly reduced in post-mortem ALS patient motor cortex and significantly reduced in the neurons of spinal cord tissue. Together, our data indicate that defects in RBM14 homeostasis, which can be due to defects in cyclin F-mediated degradation, may be a common factor underlying ALS/FTD disease pathogenesis.
2021-03-18 | PXD014163 | Pride
Project description:Dysregulation of RNA processing contributes to neurodegenerative diseases, especially amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Expansion of an intronic (GGGGCC)n repeat within the C9ORF72 gene is the most common cause of both FTD and ALS (C9-FTD/ALS), characterized with aberrant repeat RNA foci in the nucleus and noncanonical translation-produced dipeptide repeat (DPR) protein inclusions in the cytoplasm. Here we elucidate that the (GGGGCC)n repeat RNA co-localizes with nuclear speckles and alters their phase separation properties and granule dynamics. Moreover, the essential nuclear speckle scaffold protein SRRM2 is sequestered into the poly-GR cytoplasmic inclusions in C9-FTD/ALS mouse model and patient postmortem tissues, exacerbating the nuclear speckle dysfunction. Impaired nuclear speckle integrity induces global exon-skipping and intron retention in human iPSC-derived neurons. Similar alternative splicing changes can be found in patient postmortem tissues. This work identified novel molecular mechanism of global RNA splicing defects by impaired nuclear speckle function in C9-FTD/ALS and revealed novel potential biomarkers or therapeutic targets.
2024-08-23 | GSE248404 | GEO
Project description:A hexanucleotide repeat expansion (HRE) in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Human imaging and experimental studies hint at early changes in the brain in C9-ALS/FTD, which remain poorly understood. To define these changes, we used cerebral organoid models derived from C9-ALS/FTD patients and controls to create a single cell RNA sequencing dataset at day 90. Together, these dataset will help to shed light on initial pathologies crucial for understanding disease onset and the design of therapeutic strategies.
2024-09-06 | GSE264012 | GEO
Project description:Neuronal polyunsaturated fatty acids are protective in FTD/ALS
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Project description:Missense mutations in UBQLN2, a protein quality control factor, are associated with neurodegenerative diseases amyotrophic lateral sclerosis (ALS) overlapping with frontotemporal dementia (FTD). The mechanisms by which these mutations lead to neurodegeneration are not fully understood. Here we describe a critical role for UBQLN2 in regulating cellular lipid metabolism, which is crucial for cell survival under nutrient stress. The stress dependent regulation of lipid metabolism by UBQLN2 is mediated by ILVBL, a UBQLN2 substrate and a key enzyme in lipid turnover. The function of UBQLN2 in promoting ILVBL degradation and maintaining intracellular lipids was compromised by ALS/FTD-linked mutations in UBQLN2. As a result of the lipid dysregulation, synaptic vesicles were deficient and neuronal death was exacerbated in mutant UBQLN2 transgenic mice or human iPSCs derived motor neurons and cortical organoids. Replenishing lipids or restoring UBQLN2 function could reverse the deficits in the UBQLN2 mutant neurons under nutrient stress. Our study reveals UBQLN2 essential role in lipid metabolism and suggests metabolic imbalance underlying ALS/FTD and related neurodegenerative conditions.
2023-12-27 | MSV000093732 | MassIVE
Project description:Using ChIP-seq to profile the genomic binding of DAXX in control and C9HRE ALS/FTD patient B lymphocytes.
2023-02-10 | GSE223401 | GEO
Project description:While deleterious mutations are responsible for the vast majority of TBK1-linked ALS/FTD cases, the ALS/FTD causing missense mutation p.E696K leads to a selective loss of TBK1/optineurin binding. Knock-in of this specific missense mutation causes progressive autophagolysosomal dysfunction and an ALS/FTD-like phenotype in mice, while, as opposed to TBK1 deletion, RIPK/TNF-α-dependent necroptosis or overt inflammation are absent. Our results highlight the role of autophagolysosomal dysfunction as a therapeutic target in TBK1-ALS/FTD.
2024-03-19 | PXD050731 | Pride
Project description:ATAC-seq was utilized to profile the chromatin status in ALS/FTD patient cells carrying the hexanuleotide repeat expansion in C9orf72.
2023-02-10 | GSE223255 | GEO