Project description:Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive paralysis due to primary and secondary degeneration of motor neurons. Despite the incredible effort of biomedical research, no curative therapy for this disease has yet been established. Given the direct interaction with neurons through neuromuscular junction (NMJ) stabilization, skeletal muscle appears to be a primary target of ALS, causing profound alteration in its function. Here we generated the first spatial transcriptomics dataset of SOD1G93A skeletal muscle as a mouse model for ALS. Using this strategy, we identified polyamine (PA) metabolism as one of the main altered pathways in affected muscle fibers. By identifying PA balance as a key factor in fiber vulnerability during disease progression, we show that perturbation of PA balance in muscle resembles disease features observed in ALS-affected muscle. Finally, we show that restoration of PA flux rescues the muscle phenotype of SOD1G93A mice, opening new perspectives in the treatment of ALS.
Project description:Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive paralysis due to primary and secondary degeneration of motor neurons. In spite of extensive biomedical research, no curative therapy has yet been established. One of the primary targets of ALS is skeletal muscle, which undergoes profound functional changes as the disease progresses. To better understand how altered innervation interferes with muscle homeostasis during disease progression, we generated the first spatial transcriptomics dataset of skeletal muscle in the SOD1G93A mouse model of ALS. Using this strategy, we identified polyamine (PA) metabolism as one of the main altered pathways in affected muscle fibers. By establishing a correlation between the vulnerability of muscle fibers and the dysregulation of this metabolic pathway, we show that disrupting polyamine homeostasis causes impairments similar to those seen in ALS muscle. Finally, we show that restoration of polyamine homeostasis rescues the muscle phenotype in SOD1G93A mice, opening new perspectives for the treatment of ALS.
Project description:Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive paralysis due to primary and secondary degeneration of motor neurons. In spite of extensive biomedical research, no curative therapy has yet been established. One of the primary targets of ALS is skeletal muscle, which undergoes profound functional changes as the disease progresses. To better understand how altered innervation interferes with muscle homeostasis during disease progression, we generated the first spatial transcriptomics dataset of skeletal muscle in the SOD1G93A mouse model of ALS. Using this strategy, we identified polyamine (PA) metabolism as one of the main altered pathways in affected muscle fibers. By establishing a correlation between the vulnerability of muscle fibers and the dysregulation of this metabolic pathway, we show that disrupting polyamine homeostasis causes impairments similar to those seen in ALS muscle. Finally, we show that restoration of PA homeostasis rescues the muscle phenotype in SOD1G93A mice, opening new perspectives for the treatment of ALS.
2025-01-01 | GSE271039 | GEO
Project description:Polyamine metabolism dysregulation contributes to muscle fiber vulnerability in ALS
Project description:Astroglia are the most abundant cell type in the central nervous system. They play essential roles in the homeostasis of the CNS. Astroglia are extremely diverse. In Amyotrophic Lateral Sclerosis (ALS) astroglia in spinal cord undergo dramatic transcriptomic dysregulation. However there is little to no data on the effects that cortical astroglia undergo during ALS pathogenesis. In this study we isolated pure cortical astroglia in end stage ALS mice. We performed microarray analysis and discovered dysregulated pathways and genetic markers. This may serve as a database for scientists to understand the effects that abnormal cortical astroglia have on cortical motor neurons and overall ALS pathology.
Project description:Aims: Loss of nuclear TDP-43 characterises sporadic and most familial forms of amyotrophic lateral sclerosis (ALS). TDP-43 (encoded by TARDBP) has multiple roles in RNA processing. We aimed to determine whether 1) RNA splicing dysregulation is present in lower motor neurons in ALS and in a motor neuron-like cell model, and 2) TARDBP mutations (mtTARDBP) are associated with aberrant RNA splicing using patient-derived fibroblasts. Methods: Affymetrix exon arrays were used to study mRNA expression and splicing in lower motor neurons obtained by laser capture microdissection of autopsy tissue from individuals with sporadic ALS and TDP-43 proteinopathy. Findings were confirmed by qRT-PCR and in NSC34 motor neuronal cells following shRNA-mediated TDP-43 depletion. Exon arrays and immunohistochemistry were used to study mRNA splicing and TDP-43 expression in fibroblasts from patients with mtTARDBP-associated, sporadic and mutant SOD1-associated ALS. Results: We found altered expression of spliceosome components in motor neurons and widespread aberrations of mRNA splicing that specifically affected genes involved in ribonucleotide binding. This was confirmed in TDP-43 depleted NSC34 cells. Fibroblasts with mtTARDBP showed loss of nuclear TDP-43 protein and demonstrated similar changes in splicing and gene expression, that were not present in fibroblasts from patients with sporadic or SOD1-related ALS. Conclusion: Loss of nuclear TDP-43 is associated with RNA processing abnormalities in ALS motor neurons, patient-derived cells with mtTARDBP, and following artificial TDP-43 depletion, suggesting that splicing dysregulation directly contributes to disease pathogenesis. Key functional pathways affected include those central to RNA metabolism. RNA was extracted from fibroblasts grown from neurologically healthy controls (n=6) and 3 groups of patients with ALS: 1) sporadic cases (n=6); 2) cases due to mutations of SOD1 (n=4); 3) cases due to mutations of TARDBP (n=3). The three ALS groups were compared to the controls.
Project description:Aims: Loss of nuclear TDP-43 characterises sporadic and most familial forms of amyotrophic lateral sclerosis (ALS). TDP-43 (encoded by TARDBP) has multiple roles in RNA processing. We aimed to determine whether 1) RNA splicing dysregulation is present in lower motor neurons in ALS and in a motor neuron-like cell model, and 2) TARDBP mutations (mtTARDBP) are associated with aberrant RNA splicing using patient-derived fibroblasts. Methods: Affymetrix exon arrays were used to study mRNA expression and splicing in lower motor neurons obtained by laser capture microdissection of autopsy tissue from individuals with sporadic ALS and TDP-43 proteinopathy. Findings were confirmed by qRT-PCR and in NSC34 motor neuronal cells following shRNA-mediated TDP-43 depletion. Exon arrays and immunohistochemistry were used to study mRNA splicing and TDP-43 expression in fibroblasts from patients with mtTARDBP-associated, sporadic and mutant SOD1-associated ALS. Results: We found altered expression of spliceosome components in motor neurons and widespread aberrations of mRNA splicing that specifically affected genes involved in ribonucleotide binding. This was confirmed in TDP-43 depleted NSC34 cells. Fibroblasts with mtTARDBP showed loss of nuclear TDP-43 protein and demonstrated similar changes in splicing and gene expression, that were not present in fibroblasts from patients with sporadic or SOD1-related ALS. Conclusion: Loss of nuclear TDP-43 is associated with RNA processing abnormalities in ALS motor neurons, patient-derived cells with mtTARDBP, and following artificial TDP-43 depletion, suggesting that splicing dysregulation directly contributes to disease pathogenesis. Key functional pathways affected include those central to RNA metabolism. RNA was extracted from lower motor neurons obtained by laser capture microdissection from autopsy material from neurologically healthy controls (n=6) and cases of sporadic ALS (n=3) and ALS due to C9ORF72 mutations (n=3).
Project description:Aims: Loss of nuclear TDP-43 characterises sporadic and most familial forms of amyotrophic lateral sclerosis (ALS). TDP-43 (encoded by TARDBP) has multiple roles in RNA processing. We aimed to determine whether 1) RNA splicing dysregulation is present in lower motor neurons in ALS and in a motor neuron-like cell model, and 2) TARDBP mutations (mtTARDBP) are associated with aberrant RNA splicing using patient-derived fibroblasts. Methods: Affymetrix exon arrays were used to study mRNA expression and splicing in lower motor neurons obtained by laser capture microdissection of autopsy tissue from individuals with sporadic ALS and TDP-43 proteinopathy. Findings were confirmed by qRT-PCR and in NSC34 motor neuronal cells following shRNA-mediated TDP-43 depletion. Exon arrays and immunohistochemistry were used to study mRNA splicing and TDP-43 expression in fibroblasts from patients with mtTARDBP-associated, sporadic and mutant SOD1-associated ALS. Results: We found altered expression of spliceosome components in motor neurons and widespread aberrations of mRNA splicing that specifically affected genes involved in ribonucleotide binding. This was confirmed in TDP-43 depleted NSC34 cells. Fibroblasts with mtTARDBP showed loss of nuclear TDP-43 protein and demonstrated similar changes in splicing and gene expression, that were not present in fibroblasts from patients with sporadic or SOD1-related ALS. Conclusion: Loss of nuclear TDP-43 is associated with RNA processing abnormalities in ALS motor neurons, patient-derived cells with mtTARDBP, and following artificial TDP-43 depletion, suggesting that splicing dysregulation directly contributes to disease pathogenesis. Key functional pathways affected include those central to RNA metabolism. RNA was extracted from NSC34 motor neuronal cells depleted of TDP-43 by shRNA (n=4), treated with control shGFP (n=4), and treated with control shLuciferase (n=3).