Project description:Amyotrophic Lateral Sclerosis (ALS) is an adult-onset and fast progression neurodegenerative disease that leads to the loss of motor neurons. Mechanisms of selective motor neuron loss in ALS are unknown. The early events occurring in the spinal cord that may contribute to motor neuron death are not described, neither astrocytes participation in the pre-symptomatic phases of the disease. In order to identify ALS early events, we performed a microarray analysis employing a whole mouse genome platform to evaluate the gene expression pattern of lumbar spinal cords of transgenic SOD1G93A mice and their littermate controls at pre-symptomatic ages of 40 and 80 days. Differentially expressed genes were identified by means of the Bioconductor packages Agi4x44Preprocess and limma. FunNet web based tool was used for analysis of over-represented pathways. Furthermore, immunolabeled astrocytes from 40 and 80 days old mice were submitted to laser microdissection and RNA was extracted for evaluation of a selected gene by qPCR. Statistical analysis has pointed to 492 differentially expressed genes (155 up and 337 down regulated) in 40 days and 1105 (433 up and 672 down) in 80 days old ALS mice. The KEGG pathways tight junction, antigen processing and presentation, oxidative phosphorylation, endocytosis, chemokine signaling pathway, ubiquitin mediated proteolysis and glutamatergic synapse were found over-represented at both 40 and 80 days pre-symptomatic ages. Ube2i gene expression was evaluated in astrocytes from both transgenic ages, being up regulated in 40 and 80 days astrocytes enriched samples. Our data points to important early molecular events occurring in pre-symptomatic phases of ALS in mouse model. Early SUMOylation process linked to astrocytes might account to non autonomous cell toxicity in ALS. Further studies on the signaling pathways presented here may provide new insights to better understand the events triggering motor neuron death in this devastating disorder. Whole lumbar spinal cord from SOD1G93A and Non transgenic controls from 40 and 80 days were used in the experiments. 4 biological replicates were used. A reference sample, comprised by RNA from different neonatal organs (heart, liver, kidney) were used in the hybridations

Project description:Amyotrophic Lateral Sclerosis (ALS) is an adult-onset and fast progression neurodegenerative disease that leads to the loss of motor neurons. Mechanisms of selective motor neuron loss in ALS are unknown. The early events occurring in the spinal cord that may contribute to motor neuron death are not described, neither astrocytes participation in the pre-symptomatic phases of the disease. In order to identify ALS early events, we performed a microarray analysis employing a whole mouse genome platform to evaluate the gene expression pattern of lumbar spinal cords of transgenic SOD1G93A mice and their littermate controls at pre-symptomatic ages of 40 and 80 days. Differentially expressed genes were identified by means of the Bioconductor packages Agi4x44Preprocess and limma. FunNet web based tool was used for analysis of over-represented pathways. Furthermore, immunolabeled astrocytes from 40 and 80 days old mice were submitted to laser microdissection and RNA was extracted for evaluation of a selected gene by qPCR. Statistical analysis has pointed to 492 differentially expressed genes (155 up and 337 down regulated) in 40 days and 1105 (433 up and 672 down) in 80 days old ALS mice. The KEGG pathways tight junction, antigen processing and presentation, oxidative phosphorylation, endocytosis, chemokine signaling pathway, ubiquitin mediated proteolysis and glutamatergic synapse were found over-represented at both 40 and 80 days pre-symptomatic ages. Ube2i gene expression was evaluated in astrocytes from both transgenic ages, being up regulated in 40 and 80 days astrocytes enriched samples. Our data points to important early molecular events occurring in pre-symptomatic phases of ALS in mouse model. Early SUMOylation process linked to astrocytes might account to non autonomous cell toxicity in ALS. Further studies on the signaling pathways presented here may provide new insights to better understand the events triggering motor neuron death in this devastating disorder.

Project description:We have investigated the process of disease-induced functional perturbation and the related transcriptional changes occurring in thoraco-lumbar spinal cord extracted from Sprague-Dawley rats heterozygous for the G93A SOD1 gene mutation (Emerging Model 2148 Het Male, Taconic USA; Wyeth and Amyotrophic Lateral Sclerosis Association 2002) using spinal cord from wild type females littermates as reference tissues. Rats were obtained from a breeding project at Taconic Breeding Services (USA). We have applied large-scale gene expression analysis to define the pattern or transcriptional changes occurring in spinal cord from the G93A SOD1 rat model from a pre-symptomatic stage, at disease onset and at end-stage disease, using Bead Array analysis (Illumina, San Diego, USA). We have pooled spinal cord from N:5 transgenic rats for each of the time points considered, using the same pools of spinal cord from sex and age-matched WT rats as reference. In this specific project, the aim was to obtain a gene ontology (GO) pathway analysis of the transcriptional changes induced by the G93A SOD1 mutation in rat spinal cord. Hence, we have opted for a sample pooling strategy, well aware that in so doing, we would not obtaineed information about individuals genes variation across the samples in study but an overall view of the activation of multi-genes molecular signals. Total RNA was isolated from the spinal cords of mutant (G93A SOD1 gene mutation) female rats sacrificed at a pre-symptomatic stage (10-week old), at disease onset and at end stage disease and from age and sex-matched wild type (WT) littermates. RNA samples obtained from spinal cord extracted from rats of the same genetic types and sacrificed at the same time points (e.g. 5 RNA samples from mutant spinal cord from end-stage rats; 5 RNA samples from mutant spinal cord from rats at disease onset; 5 RNA samples from mutant pre-symptomatic rats and 5 RNA samples from spinal cord obtained from age-matched WT rats sacrificed at each of the 3 time points) were pooled and used for gene expression analysis and Ontology analysis of the expression profiles.

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