Project description:The transgenic mice expressing the human mutated form (G93A) of the SOD1 gene represent a valuable model of Amyotrophic Lateral Sclerosis (ALS). SOD1 is one of the main causative genes of familial ALS which accounts for 10% of cases. These transgenic animals develop a motorneuronal pathology that recapitulates well the neuropathological features occuring in ALS patients, and the progression of the disease can be monitored by a series of motor tests. Gastrocnemius is the first and most affected muscle in the disease, while triceps is relatively spared. Gene expression data of degenerating motor neurons at different disease stages are already available, while gene expression data on the muscle tissue are missing. Our aim is to define the role of muscle in motor neuron degeneration in ALS. Keywords: Single stage analysis (presymptomatic stage, 7 week-old mice) We considered two sets of muscle at presymptomatic stage (7 weeks): gastrocnemius and triceps from 4 transgenic SOD1G93A and 4 non-transgenic mice (NTg).
Project description:The transgenic mice expressing the human mutated form (G93A) of the SOD1 gene represent a valuable model of Amyotrophic Lateral Sclerosis (ALS). SOD1 is one of the main causative genes of familial ALS which accounts for 10% of cases. These transgenic animals develop a motorneuronal pathology that recapitulates well the neuropatological features occuring in ALS patients, and the progression of the disease can be monitored by a series of motor tests. Gastrocnemius is first and most affected muscle in the disease, while triceps is relatively spared. Gene expression data of degenerating motor neurons at different disease stages are already available, while gene expression data on the muscle tissue are missing. Our aim is to define the role of muscle in motor neuron degeneration in ALS. Keywords: Single stage analysis (early symptomatic stage, 14 weeks-old mice) We considered two sets of muscle at symptomatic stage (14 weeks): gastrocnemius and triceps from 4 transgenic SOD1G93A and 4 non-transgenic mice (NTg). Gastrocnemius from 4 nerve-crushed mice were also considered as controls for the denervation process
Project description:The transgenic mice expressing the human mutated form (G93A) of the SOD1 gene represent a valuable model of Amyotrophic Lateral Sclerosis (ALS). SOD1 is one of the main causative genes of familial ALS which accounts for 10% of cases. These transgenic animals develop a motorneuronal pathology that recapitulates well the neuropatological features occuring in ALS patients, and the progression of the disease can be monitored by a series of motor tests. Gastrocnemius is first and most affected muscle in the disease, while triceps is relatively spared. Gene expression data of degenerating motor neurons at different disease stages are already available, while gene expression data on the muscle tissue are missing. Our aim is to define the role of muscle in motor neuron degeneration in ALS. Keywords: Single stage analysis (early symptomatic stage, 14 weeks-old mice)
Project description:The transgenic mice expressing the human mutated form (G93A) of the SOD1 gene represent a valuable model of Amyotrophic Lateral Sclerosis (ALS). SOD1 is one of the main causative genes of familial ALS which accounts for 10% of cases. These transgenic animals develop a motorneuronal pathology that recapitulates well the neuropathological features occuring in ALS patients, and the progression of the disease can be monitored by a series of motor tests. Gastrocnemius is the first and most affected muscle in the disease, while triceps is relatively spared. Gene expression data of degenerating motor neurons at different disease stages are already available, while gene expression data on the muscle tissue are missing. Our aim is to define the role of muscle in motor neuron degeneration in ALS. Keywords: Single stage analysis (presymptomatic stage, 7 week-old mice)
Project description:BACKGROUND: Histone deacetylase 4 (HDAC4) has been proposed as a target for the treatment of Amyotrophic Lateral Sclerosis (ALS) because it mediates nerve-skeletal muscle interaction and since its expression in skeletal muscle correlates with the severity of the disease. However, our recent studies on the skeletal muscle response upon long-term denervation highlighted the importance of HDAC4 in maintaining muscle integrity. METHODS: To fully identify the yet uncharacterized HDAC4 functions in ALS, we genetically deleted HDAC4 in skeletal muscles of a mouse model of ALS. Body weight, skeletal muscle, innervation and spinal cord were analyzed over time by morphological and molecular analyses. A transcriptome analysis was also performed to delineate the signaling modulated by HDAC4 in skeletal muscle of a mouse model of ALS. FINDINGS: HDAC4 deletion in skeletal muscle caused earlier ALS onset, characterized by body weight loss, muscle denervation and atrophy, and compromised muscle performance in ALS mice, although the main catabolic pathways were not activated. A transcriptome analysis identified the gene networks modulated by HDAC4 in ALS, revealing UCP1 as a top regulator that may be implicated in worsening ALS features. INTERPRETATION: HDAC4 plays an important role in preserving innervations and skeletal muscle in ALS, likely by modulating the UCP1 gene network. Our study highlights a possible risk in considering HDAC inhibitors for the treatment of ALS.
Project description:Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neuromuscular disorder characterized by the selective degeneration of upper and lower motor neurons, progressive muscle wasting and paralysis. To define the full set of alterations in gene expression in skeletal muscle during the course of the disease, we performed high-density oligonucleotide microarray analysis of gene expression in hind limb skeletal muscles of sod1(G86R) mice, one of the existing transgenic models of ALS. To monitor denervation-dependent gene expression, we determined the effects of short-term acute denervation on the muscle transcriptome after sciatic nerve axotomy.
Project description:Skeletal muscle denervation is a characteristic feature of neuromuscular diseases such as amyotrophic lateral sclerosis (ALS) and sarcopenia, leading to atrophy, loss of muscle strength, and poor patient outcomes. Myofibers are typically classified into slow oxidative and fast glycolytic types based on their contractile and metabolic properties. Neuromuscular diseases predominantly affect fast myofibers, while slow myofibers are relatively spared. However, the mechanisms underlying the heightened susceptibility of fast myofibers to disease and atrophy remain unclear. To investigate this, we analyzed the transcriptional profiles of innervated and denervated myonuclei. Our findings revealed that the fast muscle gene program and the transcription factor Maf are repressed during denervation. Notably, overexpression of Maf in the skeletal muscles of mice prevented loss of muscle mass and myofiber atrophy caused by denervation. Single-nucleus RNA sequencing and ATAC sequencing demonstrated that Maf overexpression reprogrammed denervated myonuclei by repressing atrophic gene programs and reactivating fast muscle gene expression. Similar repression of fast muscle genes and Maf was observed in muscles from mice and humans with ALS. Consistent with these findings, Maf overexpression in human skeletal muscle cells induced the expression of fast muscle genes while suppressing atrophic gene expression. Our findings highlight a key role for Maf in maintaining muscle mass and demonstrate that its repression contributes to the progression of neuromuscular diseases in both mice and humans. Modulating Maf activity could offer a promising therapeutic strategy to preserve skeletal muscle function during disease, aging, or injury.
Project description:Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive motor neuron loss and muscle atrophy. Hyperphosphorylated aggregation of the RNA-binding protein, TDP-43, in the motor cortex and spinal cord are defining molecular features of ALS, suggesting TDP-43 dysfunction underlies disease pathogenesis. This phenomenon, however, has been difficult to recapitulate endogenously in animal models, impeding characterization of TDP-43 pathobiology in neurodegeneration. In this study, we report age-dependent accumulation of TDP-43 pathology in the spinal cord and progressive muscle-related deficits in transgenic mice expressing the ALS-associated PFN1C71G mutant protein. We show that transgenic neuronal expression of PFN1C71G induces early hyperphosphorylation of endogenous TDP-43 in the spinal cord that augments over time, preceding accumulation of insoluble non-phosphorylated TDP-43 and the manifestation of muscle denervation and motor dysfunction. Sustained knockdown of Atxn2 in the central nervous system (CNS) in pre-symptomatic PFN1C71G mice by AAV-driven expression of an artificial microRNA (AAV-amiR-Atxn2) reduces aberrant TDP-43 in the spinal cord, while delaying neurodegeneration and improving muscle and motor function. RNA-sequencing analysis of spinal cord samples from PFN1C71G mice and ALS donors show shared patterns of transcriptional perturbation, including a pro-inflammatory gene signature that is attenuated by AAV-amiR-Atxn2. Notably, impaired regulation of the PFN1C71G skeletal muscle transcriptome exceeds that of the spinal cord and also improved by Atxn2 reduction in the CNS. Lastly, we find significant gene co-expression network homology between PFN1C71G mice and human ALS, with shared dysregulation of modules related to neuroinflammation and neuronal function and uncover novel hub genes that provide biological insight into ALS and potential drug targets that can be further investigated in this mouse model.
Project description:Background Amyotrophic lateral sclerosis (ALS) is an age-dependent and incurable neurodegenerative disease. It is pathologically characterized by selective degeneration of motor neurons resulting in a catastrophic loss of motor function. Previous studies showed that excess copper (Cu) might have a role in ALS etiology. However, the underlying mechanism remains incompletely elucidated. Therefore, we aimed to investigate the neurotoxicity and underlying mechanism of Cu exposure in female ALS mice with SOD1G93A gene mutation. Methods After three months of treatment with low-dose Cu exposure (0.13 PPM copper chloride drinking water), the motor ability was assessed by various behavioral methods, including climbing-pole test, rotarod test, hanging endurance test, grip strength test and gait analysis. Muscle atrophy and fibrosis were evaluated by histopathology. The proliferation of astrocytes and microglia was assessed by immunohistochemical analysis. The number of motor neurons in the spinal cord was determined by Nissl staining and ChAT immunohistochemical staining. Western blotting and proteomics revealed the effect of Cu exposure on mitochondrial protein expression in mice. Results Behavioral tests showed that Cu exposure worsened motor function in SOD1G93A mice. Compared with SOD1G93A transgenic mice, there was no significant difference in the pole-climbing test after Cu exposure (P =0.6156). There were significant changes in rotarod test, hanging endurance test and grip strength test (P =0.0121; P = 0.0085; P =0.0105). At the same time, Cu exposure aggravated muscle fibrosis and the loss of spinal motor neurons (P <0.05) and was associated with neuroinflammation (P <0.05). The proteomic analysis further showed that differentially expressed proteins among wild-type mice (WT), ALS mice, and Cu-treated ALS mice were mainly involved in muscle contraction, ATP metabolic processes, immune responses, peroxisomes, mitochondrial electrons respiratory transport chain, GMP biological processes, and were co-related with disturbances in energy metabolism, which was reflected in mitochondrial dysfunction in ALS mice. In addition, Western Blot showed that Cu exposure decreased the expression of mitochondria-related proteins (P <0.05), which was consistent with the results of proteomic analysis. Conclusions In conclusion, our findings showed that Cu exposure aggravates motor dysfunction and pathological changes in ALS mice via mitochondrial dysfunction.