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Ernst-affy-mouse-264940

ABSTRACT: Inherited mutations of calcium ion channels exhibit neurological defects, such as epilepsy, ataxia, and migraine, and these phenotypes are shared among humans and mouse models. Absence epilepsy and ataxic phenotypes are present in the calcium channelopathy mutants stargazer (stg-gamma2 subunit), tottering (tg-alpha1 subunit), and lethargic (lh-beta4 subunit). These mutations of high-voltage-activated (HVA) calcium channel subunits initiate increases in membrane excitability of low-voltage-activated (LVA) calcium channels in thalamic neurons, thus enhancing LVA currents. Elevated LVA currents, produced from T-type calcium channels, induce rhythmic thalamocortical burst firing and spike-wave seizures. The changes in gene expression originating from the different mutations result in similar T-type channel function; however, the network of gene modifications causing altered molecular plasticity and the emergence of pathological phenotypes remain unknown. We would like to understand how loss of 3 different subunits of a calcium ion channel differentially alter gene expression in the brain. Characterizing the gene expression profiles of the mutant stg, tg, and lh mice will provide evidence of the epileptic and ataxic mechanisms, which may identify potential therapeutic targets. We will compare the gene expression profiles among adult mutant stg, tg, and lh mice, which display the ataxic and epileptic phenotypes, along with their wildtype, litter-mate controls, in the cerebellum and brain (without cerebellum). We propose that the neuronal dysfunction associated with the ataxic and epileptic phenotypes develops from a common network of interacting gene alterations within the mutant stg, tg, and lh brain. The changes dictated by the initial mutations leading to the ataxic and epileptic phenotypes are hypothesized to be localized to the cerebellum and the remaining areas of the brain, including the thalamus and cortex, respectively. Adult mutant stg, tg, and lh mice, between 2 and 5 months of age, along with wildtype, litter-mate controls, will be sacrificed. Two brain regions responsible for two phenotypes will be examined. The cerebellum (ataxia) will be dissected from remainder of the forebrain (generalized epilepsy). Each tissue set will be collected in triplicate (3 separate mice per set) to account for biological variance, and total RNA isolated via standard Trizol procedure (Invitrogen) and purified with the RNeasy cleanup kit (Qiagen). RNA samples will be stored at -80 C until sent for analysis using the Affymetrix GeneChip Mouse Genome 430 2.0 whole genome array. Keywords: other

ORGANISM(S): Mus musculus

PROVIDER: GSE6275 | GEO | 2006/11/14

SECONDARY ACCESSION(S): PRJNA99665

REPOSITORIES: GEO

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Project description:Inherited mutations of calcium ion channels exhibit neurological defects, such as epilepsy, ataxia, and migraine, and these phenotypes are shared among humans and mouse models. Absence epilepsy and ataxic phenotypes are present in the calcium channelopathy mutants stargazer (stg-gamma2 subunit), tottering (tg-alpha1 subunit), and lethargic (lh-beta4 subunit). These mutations of high-voltage-activated (HVA) calcium channel subunits initiate increases in membrane excitability of low-voltage-activated (LVA) calcium channels in thalamic neurons, thus enhancing LVA currents. Elevated LVA currents, produced from T-type calcium channels, induce rhythmic thalamocortical burst firing and spike-wave seizures. The changes in gene expression originating from the different mutations result in similar T-type channel function; however, the network of gene modifications causing altered molecular plasticity and the emergence of pathological phenotypes remain unknown. We would like to understand how loss of 3 different subunits of a calcium ion channel differentially alter gene expression in the brain. Characterizing the gene expression profiles of the mutant stg, tg, and lh mice will provide evidence of the epileptic and ataxic mechanisms, which may identify potential therapeutic targets. We will compare the gene expression profiles among adult mutant stg, tg, and lh mice, which display the ataxic and epileptic phenotypes, along with their wildtype, litter-mate controls, in the cerebellum and brain (without cerebellum). We propose that the neuronal dysfunction associated with the ataxic and epileptic phenotypes develops from a common network of interacting gene alterations within the mutant stg, tg, and lh brain. The changes dictated by the initial mutations leading to the ataxic and epileptic phenotypes are hypothesized to be localized to the cerebellum and the remaining areas of the brain, including the thalamus and cortex, respectively. Adult mutant stg, tg, and lh mice, between 2 and 5 months of age, along with wildtype, litter-mate controls, will be sacrificed. Two brain regions responsible for two phenotypes will be examined. The cerebellum (ataxia) will be dissected from remainder of the forebrain (generalized epilepsy). Each tissue set will be collected in triplicate (3 separate mice per set) to account for biological variance, and total RNA isolated via standard Trizol procedure (Invitrogen) and purified with the RNeasy cleanup kit (Qiagen). RNA samples will be stored at -80 C until sent for analysis using the Affymetrix GeneChip Mouse Genome 430 2.0 whole genome array.

Project description:<h4><strong>INTRODUCTION: </strong>Approximately 1% of the world's population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD's success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation.</h4><h4><strong>OBJECTIVES: </strong>The goal of this study was to explore changes in the lipidome in hippocampal and cortical tissue from Kv1.1-KO model of epilepsy.</h4><h4><strong>METHODS: </strong>FT-ICR/MS analysis was utilized to examine nonpolar metabolome of cortical and hippocampal tissue isolated from a Kv1.1 channel knockout mouse model of epilepsy (n = 5) and wild-type mice (n = 5).</h4><h4><strong>RESULTS: </strong>Distinct metabolic profiles were observed, significant (p < 0.05) features in hippocampus often being upregulated (FC ≥ 2) and the cortex being downregulated (FC ≤ 0.5). Pathway enrichment analysis shows lipid biosynthesis was affected. Partition ratio analysis revealed that the ratio of most metabolites tended to be increased in Kv1.1-/-. Metabolites in hippocampal tissue were commonly upregulated, suggesting seizure initiation in the hippocampus. Aberrant mitochondrial function is implicated by the upregulation of cardiolipin, a common component in the mitochondrial membrane.</h4><h4><strong>CONCLUSION: </strong>Generally, our study finds that the lipidome is changed in the hippocampus and cortex in response to Kv1.1-KO indicating changes in membrane structural integrity and synaptic transmission.</h4>

Project description:Despite the well-established role of the frontal and posterior peri-sylvian cortices in many facets of human-cognitive specializations, including language, little is known about the developmental patterning of these regions in human brain. We performed a genome-wide analysis of human cerebral patterning during mid-gestation, a critical epoch in cortical regionalization. A total of 345 genes were identified as differentially expressed (DE) between superior temporal gyrus (STG) and the remaining cerebral cortex (CTX). GO categories representing transcription factors were enriched in STG, while cell-adhesion and extracellular matrix molecules, were enriched in the other cortical regions. Q-PCR or in situ hybridization were performed to validate differential expression in a subset of 32 genes, most of which were confirmed. LIM domain binding 1 (LDB1), which we show to be enriched in the STG, is a recently identified interactor of LIM domain only 4 (LMO4), a gene known to be involved in the asymmetric pattering of the peri-sylvian region in the developing human brain. Protocadherin 17 (PCDH17), a neuronal cell adhesion molecule, was highly enriched in focal regions of the human prefrontal cortex. Contactin Associated Protein-Like 2 (CNTNAP2), in which mutations are known to cause autism, epilepsy and language delay, showed a remarkable pattern of anterior enriched expression in cortical regions important for human higher cognition. Importantly, a similar pattern was not observed in the mouse or rat. These data highlight the importance of expression analysis of human brain and the utility of cross-species comparisons of gene expression. Genes identified here provide a foundation for understanding molecular aspects of human-cognitive specializations and disorders that disrupt them. Experiment Overall Design: Fresh frozen human mid-gestation brains were obtained from the NICHD Brain and Tissue Bank for Developmental Disorders (University of Maryland, Baltimore, MD). After separation of the two hemispheres, tissue from STG was extracted. RNA from STG and remaining CTX was hybridized on both Agilent G4110A arrays (n=8) and Affymetrix HGU133A arrays (n=17).

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Ernst-affy-mouse-264940

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