Gene expression profiling of muscles from transgenic humanSODG93A mice at symptomatic stage
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ABSTRACT: 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 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)
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:Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease that affects motoneurons. Mutations in superoxide dismutase 1 (SOD1) have been described as a causative genetic factor for ALS. Mice overexpressing ALS-linked mutant SOD1 develop ALS symptoms accompanied by histopathological alterations and protein aggregation. Protein disulfide isomerase family member ERp57 is one of the main up-regulated proteins in tissue of ALS patients and mutant SOD1 mice, whereas point mutations in ERp57 were described as possible risk factors. ERp57 catalyzes disulfide bond formation and isomerization in the endoplasmic reticulum (ER), constituting a central component of protein quality control mechanisms. However, the actual contribution of ERp57 to ALS pathogenesis remains to be defined. Here, we studied the consequences of overexpressing ERp57 in ALS onset and progression of mutant SOD1G93A mice. The double transgenic SOD1G93A/ERp57WT mice presented improved motor performance, in addition to delayed deterioration of electrophysiological activity of affected muscles compared to single transgenic SOD1G93A littermates at early symptomatic stage. The overexpression of ERp57 reduced mutant SOD1 aggregation, but only at disease end-stage. Instead, the neuroprotective effects of ERp57 were correlated with preserved muscle innervation. Importantly, proteomic analysis revealed that the overexpression of ERp57 increases the levels of synaptic proteins in the spinal cord. Taken together, our results suggest that ERp57 operates as a disease modifier at early stages by maintaining motoneuron connectivity.
Project description:Recent genetic studies of ALS patients have identified several forms of ALS that are associated with mutations in RNA binding proteins. In animals or cultured cells, such defects broadly affect RNA metabolism. This raises the question of whether all forms of ALS have general effects on RNA metabolism. We tested this hypothesis in a mouse model of ALS that is transgenic for a human disease-causing mutation in the enzyme superoxide dismutase 1 (SOD1). We analyzed RNA from laser-captured spinal cord motor neuron cell bodies of the mutant SOD1 strain, comparing the RNA profile with that from a corresponding wild-type SOD1 transgenic strain. We prepared the samples from animals that were presymptomatic, but which manifested abnormalities at the cellular level that are seen in ALS, including aggregation of the mutant protein in motor neuron cell bodies and defective morphology of neuromuscular junctions, the connections between neuron and muscle. We observed only minor changes in the level and splicing of RNA in the SOD1 mutant animals as compared with wild-type, suggesting that mutant SOD1 produces the toxic effects of ALS by a mechanism that does not involve global RNA disturbance. RNA-Seq of laser microdissection of motor neuron bodies from two biological replicates each of SOD1 YFP (wildtype 592) and SOD1 G85R YFP (737) transgenic mice.
Project description:Amyotrophic lateral sclerosis (ALS) is a lethal motor neuron disease that progressively debilitates neuronal cells that control voluntary muscle activity. In a mouse model of ALS that expresses mutated human superoxide dismutase 1 (SOD1-G93A) skeletal muscle is one of the tissues affected early by mutant SOD1 toxicity. Fast-twitch and slow-twitch muscles are differentially affected in ALS patients and in the SOD1-G93A model, fast-twitch muscles being more vulnerable. We used miRNA microarrays to investigate miRNA alterations in fast-twitch (EDL) and slow-twitch (soleus) skeletal muscles of symptomatic SOD1-G93A animals and their age-matched wild type littermates.
Project description:Amyotrophic lateral sclerosis (ALS) is a lethal motor neuron disease that progressively debilitates neuronal cells that control voluntary muscle activity. In a mouse model of ALS that expresses mutated human superoxide dismutase 1 (SOD1-G93A) skeletal muscle is one of the tissues affected early by mutant SOD1 toxicity. Fast-twitch and slow-twitch muscles are differentially affected in ALS patients and in the SOD1-G93A model, fast-twitch muscles being more vulnerable. We used miRNA microarrays to investigate miRNA alterations in fast-twitch (EDL) and slow-twitch (soleus) skeletal muscles of symptomatic SOD1-G93A animals and their age-matched wild type littermates. At age of 90 days RNA was extracted from extensor digitorum longus (EDL) and soleus (SOL) muscles of male SOD1-G93A animals and their age-matched wild type male littermates. RNA was hybridized on Affymetrix Multispecies miRNA-2_0 Array.
Project description:Microarray analysis has been applied to the study of ALS in order to investigate gene expression in whole spinal cord homogenates of SOD1 G93A mice and human ALS cases, although the massive presence of glial cells and inflammatory factors has made it difficult to define which gene expression changes were motor neuron specific. Recently, laser capture microdissection (LCM), combined with microarray analysis, has allowed the identification of motor neuron specific changes in gene expression in human ALS cases. The aim of the present study is to combine LCM and microarray analysis to study how motor neurons in the spinal cord of transgenic SOD1 G93A mice and transgenic SOD1 WT respond to stimuli determined by the presence of the human mutant protein throughout the evolution of the stages in motor neuron injury Experiment Overall Design: Motor neurons have been isolated from the spinal cord of G93A mice and non transgenic littermates at different time points and the transcription expression profile of the isolated motor neurons has been analysed
Project description:In familial forms of amyotrophic lateral sclerosis (ALS) caused by mutations in superoxide dismutase-1 (SOD1) gene, both cell-autonomous and non-cell-autonomous mechanisms lead to the selective degeneration of motoneurons. Gene-targeted deletion of mutated SOD1 in mature astrocytes has been shown to slow down disease progression. However, the potential therapeutic application of targeting astrocytes has not been evaluated yet. Here, an AAV vector encoding an artificial microRNA is used to deliver RNA interference against mutated SOD1 by targeting astrocytes in ALS mice. In mice expressing the mutated SOD1G93A protein, we found that the treatment leads to the progressive rescue of neuromuscular junction occupancy, to the recovery of the compound muscle action potential in the gastrocnemius muscle, and significantly improves neuromuscular function. In the spinal cord, gene therapy targeting astrocytes protects a small pool of fast-fatigable motoneurons until disease end stage. In the gastrocnemius muscle of the treated SOD1G93A mice, the fast-twitch type IIb muscle fibers are preserved from atrophy. Axon collateral sprouting is observed together with muscle fiber type grouping indicative of denervation/re-innervation events. The transcriptome profiling of spinal cord motoneurons shows changes in the expression levels of factors regulating the dynamics of microtubules. Gene therapy delivering RNA interference against mutated SOD1 in astrocytes provides therapeutic effects enhancing motoneuron plasticity and improving neuromuscular function in ALS mice.
Project description:Microarray analysis has been applied to the study of ALS in order to investigate gene expression in whole spinal cord homogenates of SOD1 G93A mice and human ALS cases, although the massive presence of glial cells and inflammatory factors has made it difficult to define which gene expression changes were motor neuron specific. Recently, laser capture microdissection (LCM), combined with microarray analysis, has allowed the identification of motor neuron specific changes in gene expression in human ALS cases. The aim of the present study is to combine LCM and microarray analysis to study how motor neurons in the spinal cord of transgenic SOD1 G93A mice and transgenic SOD1 WT respond to stimuli determined by the presence of the human mutant protein throughout the evolution of the stages in motor neuron injury Keywords: Murine motor neurons