Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Genome-wide analysis of kainic acid-induced gene expression in dentate gyrus from CTR and SRF knockout mice.

ABSTRACT: To identify genes regulated by SRF in response to increased neuronal activity whole-genome expression profiling (Illumina Mouse WG-6 microarrays) of kainic acid-induced genes were performed. We found that loss of SRF in DG leads to specific deficits in activity-induced gene expression. Identified genes functions are associated with synapse plasticity, epilepsy, outgrowth of neurites, behavior and MAPK signaling pathway. The microarray experiment was performed to identify SRF-dependent activity-induced genes, using brain-specific, inducible SRF gene knockout mice. Conditional mutants of Srf were obtained by crossing mice in which Srf gene was flanked by loxP sites (Srf f/f) with an CaMKCreERT2 line to ablate its expression exclusively in excitatory forebrain neurons. Knockouts (KO = Srf f/f;CaMKCreERT2) and control littermates (CTR = Srf f/f) were used in the experiments. To enable time-specific induction of SRF deletion, adult mice, were injected with tamoxifen. Global gene expression induced by kainic acid (KA, 35-50 mg/kg) was analyzed. At 6 hours after seizures induction (seizures severity 5; according to modified Racine scale) or saline injection, CTR and KO animals were sacrificed and dentate gyrus was microdissected and used for RNA isolation. In order to identify SRF-regulated genes, we used Illumina MouseWG-6 v2.0 Expression BeadChips.

ORGANISM(S): Mus musculus

SUBMITTER: Marcin Piechota

PROVIDER: E-GEOD-60772 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:Nicotine, acting through the neuronal nicotinic acetylcholine receptors (nAChR), can induce seizures in mice. We aimed to study brain transcriptional response to seizure and to identify genes whose expression is altered after nicotine-induced seizures. Whole brains of untreated mice were compared to brains one hour after seizure activity, using Affymetrix U74Av2 microaarays. Experimental groups included wild-type mice and both nicotine-induced seizures sensitive and resistant nAChR mutant mice. Each genotype group received different nicotine doses to generate seizures. This approach allowed the identification of significantly changed genes whose expression was dependent on seizure activity, nicotine administration or both, but not on the type of nAChR subunit mutation or the amount of nicotine injected. Significant expression changes were detected in 62 genes (p < 0.05, FDR correction). Among them, GO functional annotation analysis determined that the most significantly over-represented categories were of genes encoding MAP kinase phosphatases, regulators of transcription and nucleosome assembly proteins. In-silico bioinformatic analysis of the promoter regions of the 62 changed genes detected the significant enrichments of 16 transcription regulatory elements (TREs), creating a network of transcriptional regulatory responses to seizures. The TREs for ATF and SRF were most significantly enriched, supporting their association with seizure activity. Our data suggest that nicotine-induced seizure in mice is a useful model to study seizure activity and its global brain transcriptional response. The differentially expressed genes detected here can help understand the molecular mechanisms underlying seizures in animal models, and may also serve as candidate genes to study epilepsy in humans. Experiment Overall Design: Whole brain expression profiles were determined in two experimental groups of mice, sixteen mice that were not treated with nicotine and twelve mice one hour after experiencing nicotine-induced seizure. The untreated group included six wild-type mice, five alpha7+/T and five beta4-/- mice. The group of mice that underwent nicotine-induced seizures included three wild-types, five alpha7+/T and four beta4-/- mice. Different doses of nicotine were injected intraperitoneally (i.p.) to each genotype group of mice in order to achieve a similar seizure score in all three genotypes.

Project description:Mesial Temporal Lobe Epilepsy (MTLE) is a chronic disease characterized by recurrent unprovoked partial seizures. Current treatments lack long-term efficacy and typically act only to ameliorate the symptomology, rather than to modify the course of the disease. Chronic kainic acid (KA)-induced models of MTLE mimic prominent histopathological and electroencephalographic features of human MTLE, including hippocampal sclerosis, CA1 neuronal loss, astrogliosis, microgliosis, and electrographic hippocampal discharges. Here we examined the transcriptional profiles of the hippocampus of KA - vs sham-injected mice from epileptogenesis to the stabilization of spontaneous recurring seizures. KA (1 nmol) or saline (sham) was injected unilaterally into the dorsal hippocampus of 12 week old C57BL/6J mice, and the ipsilateral (IL) and contralateral (CL) hippocampi were isolated for whole-genome expression profiling (Illumina microarray) or immunohistochemistry 7, 28 and 60 d later. Differential gene expression analysis of the IL hippocampus indicated that 1349, 484, and 439 genes were significantly (fdr<0.05) altered in KA compared to sham at 7, 28 and 60 d, respectively. 108 genes were altered at all time-points assessed, while others were altered in a time-dependent manner, indicative of distinct hippocampal gene expression profiles across the course of disease. Ingenuity Pathway Analysis revealed that specific immune cell and inflammatory signaling pathways were upregulated at 7 and 28 d, in support of a role of neuroinflammation in the disease etiology. The top canonical pathways profile at 60 d was quite distinct from that at 7 and 28 d, although certain inflammatory pathways were still prevalent, indicative of pathways involved in the maintenance of the disease. Consistent with a role of neuroinflammation in MTLE, immunohistochemical analyses demonstrated time-dependent changes in both the intensity of immunoreactivity and number of Iba1- and GFAP-positive cells. To reveal gene networks not apparent with differential expression data alone, weighted gene co-expression analysis (WGCNA) was performed. A gene network that highly associated with 7 d IL-KA (but not 28 and 60 d) was identified, which may point to changes involved in the process of epileptogenesis. Another gene network revealed a group of genes highly associated with changes occurring at 28 and 60 d, but not 7 d, which may point to molecules involved in the generation of spontaneous recurring seizures. Collectively, results indicate that specific pathways, including many associated with neuroinflammation, are activated in a time-dependent manner in MTLE.

Dataset Information

Genome-wide analysis of kainic acid-induced gene expression in dentate gyrus from CTR and SRF knockout mice.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure