Project description:Neither the molecular basis of the pathologic tendency of neuronal circuits to generate spontaneous seizures (epileptogenicity) nor anti-epileptogenic mechanisms that maintain a seizure-free state are well understood. Here, we performed transcriptomic analysis in the intrahippocampal kainate model of temporal lobe epilepsy in rats using both Agilent and Codelink microarray platforms to characterize the epileptic processes. The experimental design allowed subtraction of the confounding effects of the lesion, identification of expression changes associated with epileptogenicity, and genes upregulated by seizures with potential homeostatic anti-epileptogenic effects. Using differential expression analysis, we identified several hundred expression changes in chronic epilepsy, including candidate genes associated with epileptogenicity such as Bdnf and Kcnj13. To analyze these data from a systems perspective, we applied weighted gene co-expression network analysis (WGCNA) to identify groups of co-expressed genes (modules) and their central (hub) genes. One such module contained genes upregulated in the epileptogenic region, including multiple epileptogenicity candidate genes, and was found to be involved the protection of glial cells against oxidative stress, implicating glial oxidative stress in epileptogenicity. Another distinct module corresponded to the effects of chronic seizures and represented changes in neuronal synaptic vesicle trafficking. We found that the network structure and connectivity of one hub gene, Sv2a, showed significant changes between normal and epileptogenic tissue, becoming more highly connected in epileptic brain. Since Sv2a is a target of the antiepileptic levetiracetam, this module may be important in controlling seizure activity. Bioinformatic analysis of this module also revealed a potential mechanism for the observed transcriptional changes via generation of longer alternatively polyadenlyated transcripts through the upregulation of the RNA binding protein HuD. In summary, combining conventional statistical methods and network analysis allowed us to interpret the differentially regulated genes from a systems perspective, yielding new insight into several biological pathways underlying homeostatic anti-epileptogenic effects and epileptogenicity. Four condition experiment with five samples per condition. The samples include right dentate gyrus from animals with seizures, left dentate gyrus from animals with seizures, right dentate gyrus from animals without seizures, and left dentate gyrus from animals without seizures. A dye swap was included.

Project description:Neither the molecular basis of the pathologic tendency of neuronal circuits to generate spontaneous seizures (epileptogenicity) nor anti-epileptogenic mechanisms that maintain a seizure-free state are well understood. Here, we performed transcriptomic analysis in the intrahippocampal kainate model of temporal lobe epilepsy in rats using both Agilent and Codelink microarray platforms to characterize the epileptic processes. The experimental design allowed subtraction of the confounding effects of the lesion, identification of expression changes associated with epileptogenicity, and genes upregulated by seizures with potential homeostatic anti-epileptogenic effects. Using differential expression analysis, we identified several hundred expression changes in chronic epilepsy, including candidate genes associated with epileptogenicity such as Bdnf and Kcnj13. To analyze these data from a systems perspective, we applied weighted gene co-expression network analysis (WGCNA) to identify groups of co-expressed genes (modules) and their central (hub) genes. One such module contained genes upregulated in the epileptogenic region, including multiple epileptogenicity candidate genes, and was found to be involved the protection of glial cells against oxidative stress, implicating glial oxidative stress in epileptogenicity. Another distinct module corresponded to the effects of chronic seizures and represented changes in neuronal synaptic vesicle trafficking. We found that the network structure and connectivity of one hub gene, Sv2a, showed significant changes between normal and epileptogenic tissue, becoming more highly connected in epileptic brain. Since Sv2a is a target of the antiepileptic levetiracetam, this module may be important in controlling seizure activity. Bioinformatic analysis of this module also revealed a potential mechanism for the observed transcriptional changes via generation of longer alternatively polyadenlyated transcripts through the upregulation of the RNA binding protein HuD. In summary, combining conventional statistical methods and network analysis allowed us to interpret the differentially regulated genes from a systems perspective, yielding new insight into several biological pathways underlying homeostatic anti-epileptogenic effects and epileptogenicity. Four condition experiment with five samples per condition. The samples include right dentate gyrus from animals with seizures, left dentate gyrus from animals with seizures, right dentate gyrus from animals without seizures, and left dentate gyrus from animals without seizures.

Project description:Drug-induced alterations in transcriptional regulation play a central role in establishing the persistent neuroplasticities that occur during drug addiction. Additionally, changes in gene expression associated with drug administration provide valuable insight into the molecular basis of drug abuse. The molecular mechanisms that underlie susceptibility to psychostimulant addiction remain unknown. Identifying the common gene transcriptional responses to psychostimulants can provide a mechanistic insight to elucidate the molecular nature of drug dependence. Male Wistar rats (4 weeks old) were acclimatized for a week to their housing conditions prior to experiments. Thereafter, they were divided into two groups: (cohort 1) 4 groups of rats (n=12 rats per group) given saline only (i.p., "drug-naive" rats); and (cohort 2): 3 groups of rats given either methamphetamine, amphetamine or methylphenidate (5 mg/kg,i.p., M-CM-"M-bM-^BM-,M-EM-^Sdrug-pretreated") for 7 days (2x daily) prior to behavioral assays. Conditioned place preference (CPP) tests were conducted a day after the final drug administration. Rats which showed CPP were evaluated for self-administration of the psychostimulants. [Cohort 1] A day after the final self-administration test, brains of 2-3 rats from each subgroups (i.e. those which showed the most robust self-administration), as well as 5 rats from the control group were removed for microarray analysis. The striatum (rostral part of the caudate putamen and the nucleus accumbens [NAc]) and the prefrontal cortex were dissected and immediately frozen at -70M-CM-^BM-BM-0C. Total RNA was isolated and gene expression profiling was conducted on independent pools of total RNA from 2-5 animals per group. [Cohort 2] A day after the final self-administration test, brains of 3 rats from each subgroups (i.e. those which showed the most robust self-administration), as well as 3 rats from the control group were removed for microarray analysis. The striatum (rostral part of the caudate putamen and the nucleus accumbens [NAc]) and the prefrontal cortex were dissected and immediately frozen at -70M-BM-0C. Total RNA was isolated and gene expression profiling was conducted on independent pools of total RNA from three animals per group.

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Identification of flap structure specific endonuclease 1 as a factor involved in LTM formation of aversive learning

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