Transcriptome analysis of CA1 rat hippocampus 1 week after kainate seizure at P7
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE136913 | GEO | 2020/04/17
REPOSITORIES: GEO
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Project description:Basic helix loop helix enhancer 40 (Bhlhe40) is a transcription factor expressed in rodent hippocampus, however, its role in neuronal function is not well understood. Here, we used Bhlhe40 null mice on a congenic C57Bl6/J background (Bhlhe40 KO) to investigate the impact of Bhlhe40 on neuronal excitability and synaptic plasticity. A whole genome expression array predicted that Bhlhe40 KO mice have up-regulated insulin-related pathways and down-regulated neuronal signaling-related pathways in the hippocampus. We validated that insulin degrading enzyme mRNA (Ide) and IDE protein are significantly downregulated in Bhlhe40 KO hippocampi. No significant difference was observed in hippocampal insulin levels. In hippocampal slices, we found CA1 neurons have increased miniature excitatory post-synaptic current (mEPSC) amplitude and decreased inhibitory post-synaptic current (IPSC) amplitude, indicating hyper-excitability in CA1 neurons in Bhlhe40 KO mice. At CA1 synapses, we found a reduction in long term potentiation (LTP) and long term depression (LTD), indicating an impairment in hippocampal synaptic plasticity in Bhlhe40 KO hippocampal slices. Bhlhe40 KO mice displayed no difference in seizure response to the convulsant kainic acid (KA) relative to controls. We found that while Bhlhe40 KO mice have decreased exploratory behavior they do not display alterations in spatial learning and memory. Together this suggests that Bhlhe40 plays a role in modulating neuronal excitability and synaptic plasticity ex vivo, however, Bhlhe40 alone does not play a significant role in seizure susceptibility and learning and memory in vivo. In addition, based on the reduction in IDE protein levels in these mice, there may be dysregulation of other known IDE substrates, namely insulin growth factor (Igf)-1, Igf-2, and Amyloid beta (Aβ).
2018-05-03 | GSE85959 | GEO
Project description:In this study we used microarray analysis to reveal the gene expression profile of the hippocampal CA1 subregion, which was laser-capture microdissected one week after kainic acid (KA)-induced status epilepticus (SE) in postnatal day 21 (P21) rats. These rats are developmentally roughly comparable to juvenile children, and KA-induced SE leads to selective damage of hippocampal CA1 pyramidal neurons in this age group while saving neurons of the other sub-regions. We searched for alterations in the gene expression pattern during the early epileptogenetic phase, i.e. one week after SE, and compared the results with those of age-matched control rats. To detect specifically changes in the CA1 pyramidal neurons, we used the laser-capture microdissection technique that allows the precise isolation of the region of interest. The RNA of this region was isolated, amplified, and labeled, and then hybridized to Illumina RatRef-12 Expression BeadChip Arrays. The gene expression data generated from the microarray was first normalized by the guantile normalization method, and then filtered by using the empirical Bayes method, and the contrasts were created by using the Limma R/Bioconductor. Finally, the data was clustered by using the non-hierarchical K-means clustering for genes, and the pathway analysis was performed by âGene set testâ, which analyzes the statistical significance of a set of genes simultaneously ranked by p-value and generates the KEGG categories (Chipster manual). The Illumina microarray analysis with the Chipster software v1.1.0 (http://chipster.csc.fi; CSC, Espoo, Finland) generated a total of 1592 differently expressed genes in the CA1 subregion of KA-treated rats compared to control rats. Using the K-means method the genes were classified in 10 different clusters. The subsequent KEGG-test for the probe set over-representation analysis revealed the 15 significantly (p<0.05) changed KEGG-pathways in response to KA-treatment, e.g. oxidative phosphorylation (26 genes changed), and long-term potentiation (LTP; 18 genes changed). Some of the differentially expressed genes were also identified to be involved in Ca2+ homeostasis, gliosis, inflammation, and GABAergic transmission.
2010-10-25 | E-TABM-881 | biostudies-arrayexpress
Project description:Early childhood convulsions have been correlated with hippocampal neuron loss in patients with intractable temporal lobe epilepsy. Using a "two-hit" rat seizure model, we have shown that animals subjected to kainate (KA)- or hypoxia-induced seizures during early postnatal period showed no cell death, yet sustained more extensive neuronal death after second seizures in adulthood. An early life seizure, without causing overt cellular injury, predisposes the brain to the damaging effect of seizures in later life. Cellular and molecular changes that accompany early seizures and that lead to subsequent epileptogenesis and increased susceptibility to seizure-induced neuronal injury, however, remain poorly understood. We propose to investigate age-specific, time-dependent changes in gene expression that may underlie this priming effect of early-life seizures. We will determine the sequence of gene expression pattern in the hippocampus at various times following KA induced seizures at postnatal day (P) 15. Previous studies have shown that AMPA receptor subtype of glutamate receptors play a crucial role in the age-specific vulnerability and in the long-term epileptogenic effects of perinatal hypoxia seizures. We found that AMPA receptor antagonists block the increased susceptibility caused by early life seizures to later seizures and seizure-induced brain damage. We hypothesize that an alteration of AMPA receptor composition is one of many changes caused by early-life seizures that leads to an increase in Ca2+ permeability, which then results in cascade of downstream events and modifies array of gene expression that promote epileptogenesis and susceptibility to neuronal death in later life. We will examine three time points: 1hr, 72 hr, and 15 days following systemic KA-induced seizures at P15 as we have previously observed structural changes within the hippocampus at these time points. Within an hour of KA seizures, a marked swelling of dendrites, disassembly of dendritic microtubules and glycogen depletion are observed by electron microscopy. Within 5 days, basal dendrites of CA3 hippocampal pyramidal neurons show abnormal spine morphology and decreased branching pattern. 15 days after the seizures, aberrant growth of mossy fibers in the CA3 stratum oriens is observed in animals exposed to KA. Ten hippocampi will be pooled from five animals treated with KA (3mg/kg i.p.) and from five littermate controls injected with PBS. Animals will be decapitated and hippocampi will be rapidly dissected from the brain, flash frozen in liquid nitrogen, and stored at -80C until extraction of total RNA, which will be sent to the center. We will provide 4 tissue samples-2 controls and 2 KA, each a pool of five animals - for each time points. Mixing tissues from multiple rats will normalize single nucleotide polymorphisms and tissue heterogeneity.
2008-06-11 | E-GEOD-1831 | biostudies-arrayexpress
Project description:Injury of the CA1 subregion induced by a single injection of kainic acid (1×KA) is attenuated when juvenile animals (P20) have a history of two sustained neonatal seizures on P6 and P9. To identify gene candidates involved in the spatially protective effects produced by early life conditioning seizures, we profiled and compared the transcriptomes of CA1 subregions from control, 1×KA, and 3×KA treated animals. More genes were regulated following 3×KA (9.6%) than after 1×KA (7.1%). Following 1×KA, genes supporting oxidative stress, growth, development, inflammation, and neurotransmission were upregulated (e.g., Cacng1, Nadsyn1, Kcng1, Aven, S100a4, GFAP, Vim, Hrsp12, Grik1). After 3×KA, protective genes were differentially over-expressed (e.g., Cat, Gpx7, GAD1, Hspa12A, Foxn1, adenosine A1 receptor, Ca2+ adaptor and homeostatic proteins, Cacnb4, Atp2b2, anti-apoptotic Bcl-2 gene members, intracellular trafficking protein, Grasp, suppressor of cytokine signaling (Socs3)). Distinct anti-inflammatory interleukins not observed in adult tissues (e.g., IL6 transducer, IL23 and IL33 or their receptors (ILF2)) were also over-expressed. Several transcripts were validated by real-time polymerase chain reaction (QPCR) and immunohistochemistry. QPCR showed that casp 6 was increased after 1×KA but reduced after 3×KA; pro-inflammatory gene cox1 was either upregulated or unchanged after 1×KA but reduced by ~70% after 3×KA. Enhanced GFAP immunostaining following 1×KA was selectively attenuated in the CA1 subregion after 3×KA. The observed differential transcriptional responses may contribute to early life seizure-induced pre-conditioning and neuroprotection by reducing glutamate receptor-mediated Ca2+ permeability of the hippocampus and redirecting inflammatory and apoptotic pathways which could lead to new genetic therapies for epilepsy.
2013-02-14 | GSE44031 | GEO
Project description:Mesial temporal lobe epilepsy (MTLE) is the most common medically refractory epilepsy syndrome; kainic acid (KA) induced seizures have been studied as a MTLE model as limbic seizures produced by systemic injections of KA result in a distinctive pattern of neurodegeneration in the hippocampus that resembles human hippocampal sclerosis. In our "2-hit" seizure model, animals subjected to seizures during week 2 of life become more susceptible to seizures later in life and sustain extensive hippocampal neuronal injury after second KA seizures in adulthood. Using high-density oligonucleotide gene arrays, we began to elucidate the molecular basis of this priming effect of early-life seizures and of the age-specific neuroprotection against seizure-induced neuronal injury. We seek to identify target genes for epileptogenesis and cell death by selecting transcripts that are differentially regulated at various times in the P15 and P30 hippocampus. To screen for and identify candidate genes responsible for epileptogenesis and seizure-induced cell death. We hypothesize that active process of cell death signaling and long-term synaptic changes leading to chronic epilepsy is mediated by distinct transcriptional responses in mature brain that are different from those in immature brain. We will select for transcripts that are highly regulated at 1, 6, 24, 72 and 240 hours (h) after KA-induced seizures at P30 compared to P15. These differentially regulated genes will serve as potential target genes for therapeutic intervention. Highly regulated genes identified in our array analysis will then be confirmed by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Causative roles of select genes will be directly tested by gene silencing using RNA interference technology or by gene delivery using viral vectors.
2008-06-11 | E-GEOD-1834 | biostudies-arrayexpress
Project description:Temporal lobe epilepsy (TLE) can develop from alterations in hippocampal structure and circuit characteristics, and can be modeled in mice by administration of kainic acid (KA). Adult neurogenesis in the dentate gyrus (DG) contributes to hippocampal functions and has been reported to contribute to the development of TLE. Some of the phenotypical changes include neural stem and precursor cells (NPSC) apoptosis, shortly after their birth, before they produce hippocampal neurons. Here we explored these early phenotypical changes in the DG 3 days after systemic KA administration to mice. Our specific aim was to understand the molecular mechanisms underlying altered apoptosis levels in NSPC following KA-induced status epilepticus (KA-SE). Accordingly, we chose a multi-omics experimental setup and analyzed DG tissue samples using proteomics, transcriptomics and microRNA profiling techniques. We here present a description of how these date were obtained and provide them to others for further analysis and validation. This may help to further identify and characterize molecular mechanisms involved in the alterations induced shortly after KA-SE in the mouse DG. Total RNA obtained from dentate gyrus 72h after mice were subjected to repeated low dose kainic acid induced status epilepticus or saline i.p. injections
2016-03-12 | E-GEOD-79131 | biostudies-arrayexpress
Project description:Temporal lobe epilepsy (TLE) can develop from alterations in hippocampal structure and circuit characteristics, and can be modeled in mice by administration of kainic acid (KA). Adult neurogenesis in the dentate gyrus (DG) contributes to hippocampal functions and has been reported to contribute to the development of TLE. Some of the phenotypical changes include neural stem and precursor cells (NPSC) apoptosis, shortly after their birth, before they produce hippocampal neurons. Here we explored these early phenotypical changes in the DG 3 days after systemic KA administration to mice. Our specific aim was to understand the molecular mechanisms underlying altered apoptosis levels in NSPC following KA-induced status epilepticus (KA-SE). Accordingly, we chose a multi-omics experimental setup and analyzed DG tissue samples using proteomics, transcriptomics and microRNA profiling techniques. We here present a description of how these date were obtained and provide them to others for further analysis and validation. This may help to further identify and characterize molecular mechanisms involved in the alterations induced shortly after KA-SE in the mouse DG. Total RNA obtained from dentate gyrus 72h after mice were subjected to repeated low dose kainic acid induced status epilepticus or saline i.p. injections
2016-03-12 | E-GEOD-79129 | biostudies-arrayexpress
Project description:We used a systemic inflammatory challenge in animals with chronic mesial temporal lobe epilepsy to identify novel molecular pathways involved in seizure regulation. Mice were first rendered epileptic by a single intrahippocampal injection of kainic acid (KA). After a period of two-three weeks, mice developed spontaneous seizures and then received a single intraperitoneal injection of lipopolysaccharide (LPS) to mimic systemic inflammation, or saline as a control. Gene expression analysis by microarrays was then performed on hippocampal RNA samples extracted 4 and 24 hours after LPS or saline treatment (n=3 samples per treatment group).
2016-05-03 | GSE81024 | GEO
Project description:Early childhood convulsions have been correlated with hippocampal neuron loss in patients with intractable temporal lobe epilepsy. Using a "two-hit" rat seizure model, we have shown that animals subjected to kainate (KA)- or hypoxia-induced seizures during early postnatal period showed no cell death, yet sustained more extensive neuronal death after second seizures in adulthood. An early life seizure, without causing overt cellular injury, predisposes the brain to the damaging effect of seizures in later life. Cellular and molecular changes that accompany early seizures and that lead to subsequent epileptogenesis and increased susceptibility to seizure-induced neuronal injury, however, remain poorly understood. We propose to investigate age-specific, time-dependent changes in gene expression that may underlie this priming effect of early-life seizures. We will determine the sequence of gene expression pattern in the hippocampus at various times following KA induced seizures at postnatal day (P) 15. Previous studies have shown that AMPA receptor subtype of glutamate receptors play a crucial role in the age-specific vulnerability and in the long-term epileptogenic effects of perinatal hypoxia seizures. We found that AMPA receptor antagonists block the increased susceptibility caused by early life seizures to later seizures and seizure-induced brain damage. We hypothesize that an alteration of AMPA receptor composition is one of many changes caused by early-life seizures that leads to an increase in Ca2+ permeability, which then results in cascade of downstream events and modifies array of gene expression that promote epileptogenesis and susceptibility to neuronal death in later life. We will examine three time points: 1hr, 72 hr, and 15 days following systemic KA-induced seizures at P15 as we have previously observed structural changes within the hippocampus at these time points. Within an hour of KA seizures, a marked swelling of dendrites, disassembly of dendritic microtubules and glycogen depletion are observed by electron microscopy. Within 5 days, basal dendrites of CA3 hippocampal pyramidal neurons show abnormal spine morphology and decreased branching pattern. 15 days after the seizures, aberrant growth of mossy fibers in the CA3 stratum oriens is observed in animals exposed to KA. Ten hippocampi will be pooled from five animals treated with KA (3mg/kg i.p.) and from five littermate controls injected with PBS. Animals will be decapitated and hippocampi will be rapidly dissected from the brain, flash frozen in liquid nitrogen, and stored at -80C until extraction of total RNA, which will be sent to the center. We will provide 4 tissue samples-2 controls and 2 KA, each a pool of five animals - for each time points. Mixing tissues from multiple rats will normalize single nucleotide polymorphisms and tissue heterogeneity. Keywords: time-course
2004-10-14 | GSE1831 | GEO
Project description:Background: Mutations in the X-linked gene cyclin-dependent kinase-like 5 (CDKL5) cause a severe neurological disorder characterised by early-onset epileptic seizures, autism and intellectual disability (ID). Impaired hippocampal function has been implicated in other models of monogenic forms of autism spectrum disorders and ID and is often linked to epilepsy and behavioural abnormalities. Many individuals with CDKL5 deficiency disorder (CDD) have null mutations and complete loss of CDKL5 protein, therefore in the current study we used a Cdkl5-/y rat model to elucidate the impact of CDKL5 loss on cellular excitability and synaptic function of CA1 pyramidal cells (PCs). We hypothesised abnormal pre and/or post synaptic function underlie the enhanced LTP we observe in the hippocampus of Cdkl5-/y rats. Methods: To allow cross-species comparisons of phenotypes associated with the loss of CDKL5, we generated a loss of function mutation in exon 5 of the rat Cdkl5 gene and assessed the impact of the loss of CDLK5 using a combination of extracellular and whole-cell electrophysiological recordings, biochemistry, and histology. Results: Our results indicate that CA1 hippocampal LTP is enhanced in slices prepared from juvenile, but not adult, Cdkl5-/y rats. Enhanced LTP does not result from changes in NMDA receptor function or subunit expression as these remain unaltered throughout development. Furthermore, Ca2+ permeable AMPA receptor mediated currents are unchanged in Cdkl5-/y rats. We observe reduced mEPSC frequency accompanied by increased spine density in basal dendrites of CA1 PCs, however we find no evidence supporting an increase in silent synapses when assessed using a minimal stimulation protocol in slices. Additionally, we found no change in paired-pulse ratio, consistent with normal release probability at Schaffer collateral to CA1 PC synapses. Conclusions: Our data indicate a role for CDKL5 in hippocampal synaptic function and raise the possibility that altered intracellular signalling rather than synaptic deficits contribute to the altered plasticity. Limitations: This study has focussed on the electrophysiological and anatomical properties of hippocampal CA1 PCs across early postnatal development. Studies involving other brains regions, older animals and behavioural phenotypes associated with the loss of CDKL5 are needed to understand the pathophysiology of CDD.
2023-08-14 | PXD043246 | Pride