Project description:The present study aimed to use RNA sequencing to reveal the gene transcriptomic profile of PTZ-induced seizure rats and the difference of the PTZ model rat before and after treatment with Q808.
Project description:Prolonged seizures can disrupt stem cell behavior in the adult hippocampus, an important brain structure for spatial memory. Here, using a mouse model of pilocarpine-induced status epilepticus (SE), we characterized spatiotemporal expression of Lin28a mRNA and proteins after SE. Unlike Lin28a transcripts, induction of LIN28A protein after SE was detected mainly in the subgranular zone, where immunoreactivity was found in progenitors, neuroblasts, and immature and mature granule neurons. To investigate roles of LIN28A in epilepsy, we generated Nestin-Cre::Lin28aloxP/loxP (cKO) and Nestin-Cre::Lin28a+/+ (WT) mice to block LIN28A upregulation in all neuronal lineages after acute seizure. Adult-generated neuron- and hippocampus-associated cognitive impairments were absent in epileptic LIN28A cKO mice as evaluated by pattern separation and contextual fear conditioning tests, respectively, while sham-manipulated WT and cKO animals showed comparable memory function. Moreover, numbers of hilar PROX1-expressing ectopic granule cells (EGCs), together with PROX1/NEUN+ mature EGCs, were significantly reduced in epileptic cKO mice. Transcriptomic analysis and immunohistochemical validation at 3 d post-pilocarpine provided potential LIN28A downstream targets such as serotonin receptor 4. Collectively, our findings indicate that LIN28A is a novel target for regulation of newborn neuron-associated memory dysfunction in epilepsy by modulating seizure-induced aberrant neurogenesis.
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. Keywords: time-course
Project description:We mapped out temporal changes in mice hippocampus transcriptome as mRNA-seq and microRNA-seq after pilocarpine-induced SE to understand better molecular and cellular pathways that lead to neurodegenerative and neuroprotective processes after SE.
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.
Project description:The initial seizure-induced events in neuronal nuclei can lead to long-term changes in gene expression and cellular responses that likely contribute toward epileptogenesis. Using a transgenic mouse model to specifically isolate excitatory neuronal nuclei, we profiled the seizure-induced nuclear transcriptome by RNA-seq, as well as proteome via tandem mass tag mass spectrometry (available at ProteomeXchange via PRIDE; Accession ID: PXD030637). In the transcriptome, we observed robust induction of genes involved in multiple processes, including MAPK signalling, and downregulation of zinc finger genes harbouring Krüppel-associated box (KRAB) domains, which were strongly enriched for binding sites of the Thap11/Ronin transcriptional repressor. Additionally, we characterised gene expression in introns, which provided further insights into seizure-driven transcriptional regulation and dynamics, including repression of transcription mediated by zinc finger transcription factors. Our results provide a detailed snapshot of nuclear events induced by seizure activity and demonstrate a robust method for cell-type-specific nuclear profiling that can be applied to other cell types and models.
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.
Project description:Neuropsychiatric consequences of poorly controlled seizures that begin in childhood can be devastating. School failure or behavioral difficulty in a child with epilepsy is common and can become the focus of concern for families. Current antiepileptic drugs compound problems with their CNS side effects; effective therapy is currently limited as little is known about the cellular and molecular changes caused by seizures in the developing brain. This study will investigate transcriptional regulation induced by early-life seizures and explore alternative nonpharmacological therapeutic strategies in reversing damages of early-life seizures. We will study the therapeutic efficacy of environmental enrichment in reducing seizure-induced neuronal injury and in modifying gene expression alterations. We will explore molecular mechanisms underlying the beneficial effects of enriched environment and examine how different genes act in concert to influence the outcome of seizure-induced damage. To test the effect of environmental enrichment in modifying KA seizure-induced alterations in gene expression. We hypothesize that environmental enrichment enhances plastic, homeostatic response of immature brain to excessive, dysregulating seizure activity and protect against maladaptive response of developing animals to seizures. After inducing seizures by systemic injection of KA (8 mg/kg) or PBS injections (control) at P20, we will randomly assign P21 male Long Evans rats to 4 groups: enrichment housing (control-enriched; SE-enriched) or to standard vivarium cages (control; SE). Sixteen animals (8 control-enriched; 8 SE-enriched) will be housed as a group in a plastic rectangular cage measuring 115cm x 80 cm containing a running wheel, tunnels, rubber balls, a maze, a mirror, and a clock with a cyclist pendulum. Control and KA will be housed individually in a standard cage. Four litters will be used for each run of experiment and the experiment will be repeated once to obtain 16 animals per group. At P30, 240 h after KA or PBS, animals will be deeply anesthetized with isoflurane, decapitated for total RNA preparation (half brain for each, n = 12 per group). Total RNA will be isolated from each hippocampus individually, and equal amounts of RNA from 4 hippocampi will be pooled for each Genechip. Three independent hybridizations will be performed per condition (total of 12 Genechip Rat Expression Set 230). Keywords: dose response
Project description:Stroke is a prevalent disorder representing the third leading cause of death and major cause of disability. Post-stroke epilepsy (PSE) has been recognized as a common clinical issue after stroke, accounting for 30-40% of the causes of epilepsy among older adults. In this study, we determined GABAA receptor-mediated seizure susceptibility after PT cerebral stroke in aged mice. Young adult mice around 10 weeks of age are widely used in stroke experiments. However, as most strokes are diagnosed in the elderly and PSE has been recognized as a common clinical incidence after stroke, we utilized photothrombosis (PT) model of cerebral ischemia and examined seizure susceptibility. To investigate in vitro drug-induced seizure susceptibility (E/I imbalance) of GABAA receptor antagonist, gabazine (GZ), voltage-sensitive dye (VSD) imaging techniques were used in hippocampal brain slices. One month after PT stroke, in vivo aged PT stroke mice exhibited severe convulsive seizures (late-onset). in vitro GZ-induced E/I imbalance in hippocampus of aging mice increased compared to young adults. In addition, Anti-seizure medication (levetiracetam) normalized in vitro GZ-induced E/I imbalance in hippocampus of aging mice. These findings exhibited that GABAA receptor-mediated seizures susceptibility (E/I imbalance) in hippocampus after cortical PT stroke in aging mice, but not in young adults.