Epilepsy In Mice Research Articles

Identification of a G-Protein-Independent Activator of GIRK Channels

G-protein-gated inwardly rectifying K+ (GIRK) channels are essential effectors of inhibitory neurotransmission in the brain. GIRK channels have been implicated in diseases with abnormal neuronal excitability, including epilepsy and addiction. GIRK channels are tetramers composed of either the same subunit (e.g., homotetramers) or different subunits (e.g., heterotetramers). Compounds that specifically target subsets of GIRK channels invivo are lacking. Previous studies have shown that alcohol directly activates GIRK channels through a hydrophobic pocket located in the cytoplasmic domain of the channel. Here, we report the identification and functional characterization of a GIRK1-selective activator, termed GiGA1, that targets the alcohol pocket. GiGA1 activates GIRK1/GIRK2 both invitro and invivo and, in turn, mitigates the effects of a convulsant in an acute epilepsy mouse model. These results shed light on the structure-based development of subunit-specific GIRK modulators that could provide potential treatments for brain disorders.

Closed-Loop Transcranial Ultrasound Stimulation for Real-Time Non-invasive Neuromodulation in vivo.

The closed-loop brain stimulation technique plays a key role in neural network information processing and therapies of neurological diseases. Transcranial ultrasound stimulation (TUS) is an established neuromodulation method for the neural oscillation in animals or human. All available TUS systems provide brain stimulation in an open-loop pattern. In this study, we developed a closed-loop transcranial ultrasound stimulation (CLTUS) system for real-time non-invasive neuromodulation in vivo. We used the CLTUS system to modulate the neural activities of the hippocampus of a wild-type mouse based on the phase of the theta rhythm recorded at the ultrasound-targeted location. In addition, we modulated the hippocampus of a temporal lobe epilepsy (TLE) mouse. The ultrasound stimulation increased the absolute power and reduced the relative power of the theta rhythm, which were independent of the specific phase of the theta rhythm. Compared with those of a sham stimulation, the latency of epileptic seizures was significantly increased, while the epileptic seizure duration was significantly decreased under the CLTUS. The above results indicate that the CLTUS can be used to not only modulate the neural oscillation through the theta-phase-specific manipulation of the hippocampus but also effectively inhibit the seizure of a TLE mouse in time. CLTUS has large application potentials for the understanding of the causal relationship of neural circuits as well as for timely, effective, and non-invasive therapies of neurological diseases such as epilepsy and Parkinson’s disease.

High mobility group box 1 antibody represses autophagy and alleviates hippocampus damage in pilocarpine-induced mouse epilepsy model

As a neurological disorder, epilepsy has affected over 65 million people all over the world because of the unforeseeable seizures it might cause. However, in-depth understandings of the pathogenesis of epilepsy and effective treatments for the disease are still lacked. Recent discoveries suggest that autophagy, as an endogenous self-cleansing pathway in mammals, might be involved in the onset of epilepsy. Our study assumes that a non-histone DNA binding protein, high mobility group box-1 (HMGB1), formerly considered as a crucial inflammatory factor, may mediate the autophagy of neurons in epileptic mouse brain. To verify this hypothesis, pilocarpine induced epilepsy mouse model was constructed. The mice were treated with HMGB1 antibody for 4 weeks after the initial epileptic seizure. Behavioral test results suggested a recovery of learning ability and memory in epileptic mice when treated with HMGB1 antibody. Pathological changes in hippocampus were inspected under microscopes and hippocampus damages caused by seizures in mouse with epilepsy such as increased intracellular space were alleviated by HMGB1 antibody treatment. Moreover, the expressions of the proteins involved in autophagy pathways were detected by immunofluorescence staining and western blot. microtubule-associated protein 1A/1B-light chain 3 (LC3), Beclin 1, autophagy protein-5 (ATG5), and ATG7 levels were significantly decreased by HMGB1 antibody while the level of p62 was increased. TdT-mediated dUTP Nick-End Labeling (TUNEL) illustrated that cell apoptosis induced by seizures in hippocampus was mitigated by HMGB1 antibody. In conclusion, we propose that HMGB1 may induce increased autophagy in epilepsy mouse model.

Brain somatic mutations in MTOR reveal translational dysregulations underlying intractable focal epilepsy.

Brain somatic mutations confer genomic diversity in the human brain and cause neurodevelopmental disorders. Recently, brain somatic activating mutations in MTOR have been identified as a major etiology of intractable epilepsy in patients with cortical malformations. However, the molecular genetic mechanism of how brain somatic mutations in MTOR cause intractable epilepsy has remained elusive. In this study, translational profiling of intractable epilepsy mouse models with brain somatic mutations and genome-edited cells revealed a novel translational dysregulation mechanism and mTOR activation-sensitive targets mediated by human MTOR mutations that lead to intractable epilepsy with cortical malformation. These mTOR targets were found to be regulated by novel mTOR-responsive 5'-UTR motifs, distinct from known mTOR inhibition-sensitive targets regulated by 5' terminal oligopyrimidine motifs. Novel mTOR target genes were validated in patient brain tissues, and the mTOR downstream effector eIF4E was identified as a new therapeutic target in intractable epilepsy via pharmacological or genetic inhibition. We show that metformin, an FDA-approved eIF4E inhibitor, suppresses intractable epilepsy. Altogether, the present study describes translational dysregulation resulting from brain somatic mutations in MTOR, as well as the pathogenesis and potential therapeutic targets of intractable epilepsy.

Cortical activation in generalized seizures.

Patients with generalized epilepsy exhibit different epileptiform events including asymptomatic interictal spikes (IS), absence seizures with spike-wave discharges (SWDs), and myoclonic seizures (MS). Our objective was to determine the spatiotemporal patterns of cortical activation in SWDs, IS, and MS in the Gabra1+/A322D juvenile myoclonic epilepsy mouse. We fabricated affordable, flexible high-density electroencephalography (HdEEG) arrays and recorded spontaneous SWD, IS, and MS with video/HdEEG. We determined differences among the events in amplitude spectral density (ASD) in the δ/θ/α/β/γ frequency bands at baseline (3.5-4.0seconds before the first spike time, t0 ) and the prespike period (0.1-0.5seconds before t0 ), and we elucidated the spatiotemporal activation during the t0 spike. All three events had an increase in ASD between baseline and prespike in at least one frequency band. During prespike, MS had the largest δ-band ASD, but SWD had the greatest α/β/γ band ASD. For all three events, the ASD was largest in the anterior regions. The t0 spike voltage was also greatest in the anterior regions for all three events and IS and MS had larger voltages than SWD. From 7.5 to 17.5msec after t0 , MS had greater voltage than IS and SWD, and maximal voltage was in the posterior parietal region. Changes in spectral density from baseline to prespike indicate that none of these generalized events are instantaneous or entirely unpredictable. Prominent engagement of anterior cortical regions during prespike and at t0 suggest that common anterior neural circuits participate in each event. Differences in prespike ASD signify that although the events may engage similar brain regions, they may arise from distinct proictal states with different neuronal activity or connectivity. Prolonged activation of the posterior parietal area in MS suggests that posterior circuits contribute to the myoclonic jerk. Together, these findings identify brain regions and processes that could be specifically targeted for further recording and modulation.

Anti-epileptic effect of 16-O-acetyldigitoxigenin via suppressing mTOR signaling pathway

Epilepsy is a common chronic disease of the central nervous system that can last for years or even decades, causing serious adverse effects on the body, mind, and psychology of patients. Traditional antiepileptic drugs can effectively control seizures, but because of large individual differences, serious adverse reactions, narrow therapeutic window and other shortcomings, more effective, new treatment drugs are looked for. Streptocaulon griffithii is a plant of Asclepiadaceae. 16-O-acetyldigitoxigenin (ACE) is a strong cardiac glycoside isolated from methanol extract of Streptocaulon griffithii. The aim of this study was to investigate the antiepileptic effect of ACE on Pilocarpine (Pilo) induced epilepsy in mice, and to explore the effect of mTOR signaling pathway on its antiepileptic effect. The results showed that ACE had antiepileptic and neuroprotective effects on Pilo induced epilepsy mice. ACE attenuates Pilo induced seizures by inhibiting the activation of p-mTOR/p-70S6K pathway, and inhibits Pilocarpine induced brain damage by inhibiting mTOR signaling pathway. These results suggest that ACE has a promising future in the treatment of epilepsy and other nervous system diseases.

Effects of antiepileptic drugs in a new TSC/mTOR-dependent epilepsy mouse model.

ObjectiveAn epilepsy mouse model for Tuberous Sclerosis Complex (TSC) was developed and validated to investigate the mechanisms underlying epileptogenesis. Furthermore, the possible antiepileptogenic properties of commonly used antiepileptic drugs (AEDs) and new compounds were assessed.Methods Tsc1 deletion was induced in CAMK2A‐expressing neurons of adult mice. The antiepileptogenic properties of commonly used AEDs and inhibitors of the mTOR pathways were assessed by EEG recordings and by molecular read outs.ResultsMice developed epilepsy in a narrow time window (10 ± 2 days) upon Tsc1 gene deletion. Seizure frequency but not duration increased over time. Seizures were lethal within 18 days, were unpredictable, and did not correlate to seizure onset, length or frequency, reminiscent of sudden unexpected death in epilepsy (SUDEP). Tsc1 gene deletion resulted in a strong activation of the mTORC1 pathway, and both epileptogenesis and lethality could be entirely prevented by RHEB1 gene deletion or rapamycin treatment. However, other inhibitors of the mTOR pathway such as AZD8055 and PF4708671 were ineffective. Except for ketogenic diet, none of commonly used AEDs showed an effect on mTORC1 activity. Vigabatrin and ketogenic diet treatment were able to significantly delay seizure onset. In contrast, survival was shortened by lamotrigine.InterpretationThis novel Tsc1 mouse model is highly suitable to assess the efficacy of antiepileptic and ‐epileptogenic drugs to treat mTORC1‐dependent epilepsy. Additionally, it allows us to study the mechanisms underlying mTORC1‐mediated epileptogenesis and SUDEP. We found that early treatment with vigabatrin was not able to prevent epilepsy, but significantly delayed seizure onset.

Alteration of GABAergic signaling is associated with anxiety-like behavior in temporal lobe epilepsy mice

Temporal lobe epilepsy (TLE), which is one of the most common neurological diseases, is accompanied by a high incidence of psychiatric disorders. Among these psychiatric disorders, anxiety is one of the major psychiatric comorbidities in epilepsy patients. However, anxiety in epilepsy patients often remains unrecognized and untreated. It is believed that the inhibitory networks of γ-aminobutyric acid (GABA) neurotransmission play pivotal roles in the modulation of emotion and mood responses in both physiological and pathological conditions. The impairment of neurotransmission mediated by GABAergic signaling is related to the pathophysiology of anxiety. However, it remains unclear whether and how GABAergic signaling modulates anxiety responses in the context of an epileptic brain. In the present study, we sought to determine the role of inhibitory networks of GABAergic signaling in the anxiety-like behavior of epileptic mice. Our results show epileptic mice exhibited increased anxiety-like behavior, and this increased anxiety-like behavior was accompanied by a decrease in GABAergic interneurons and an increase in GABA type A receptor (GABAAR) β3 subunit (GABRB3) expression in the hippocampus. Furthermore, the activation of GABAARs produced an anxiolytic-like effect, while the inhibition of GABAARs elicited an anxiogenic-like effect in the epileptic mice, suggesting that the alteration of GABAergic signaling is associated with anxiety-like behavior in epileptic mice. Thus, targeting GABAergic signaling in the epileptic brain may provide an effective anxiolytic treatment in epilepsy patients.

Effect of glycine transporter 1 inhibitor on epileptic seizures and cognitive dysfunction in epilepsy mice

Objective To study the effect of glycine transporter 1 inhibitor M22 on epileptic seizures and cognitive dysfunction in epilepsy mice. Methods A total of 110 C57BL/6 mice were randomly divided into Normal control group (CON group, n=10), Model group (Mod group n=20), M22-1 group (n=20), M22-2 group (n=20), M22-3 group (n=20), M22-4 group (n=20) according to weight.The chronic epileptic model was established by intraperitoneal injection of PTZ(30 mg/kg). The mice in CON group was injected with normal saline(10 mg/kg). The mice in Mod group were intraperitoneally injected with normal saline (10 ml/kg) and were injected with PT2 30 min later.The mice in M22-1 group, M22-2 group, M22-3 group, M22-4 group were intraperitoneally injected with M22 of corresponding dose(10 mg/kg, 20 mg/kg, 40 mg/kg, 80 mg/kg)respectively, lasting for 2 weeks.Epilepsy seizures of mice in each group were recorded.The learning and memory function of epilepsy mice were evaluated by Morris water maze test .Then the mice were sacrificed and the apoptosis related proteins Bcl-2, Bax, Cyt-c in the cerebral cortex of mice were measured by Western blot. Results (1)The mortality kindling rate, epileptic seizure grade and rate of tonic clonus in M22-2 and M22-3 group were significantly lower than those in Mod, M22-1 and M22-4 group(all P 0.05). Conclusion M22 (40 mg/kg) has significant anti-epileptic effect and can effectively improve the cognitive dysfunction of epileptic mice, which may be related to the inhibition of neuronal apoptosis in mice. Key words: Epilepsy; Glycine transporter 1 inhibitor; M22; Cognitive function; Pentylenetetrazole

Effect of Sirolimus attenuating kainic acid-induced epilepsy in mice

Objective To explore the therapeutic mechanism of in response to kainic acid-induced epilepsy in mice. Methods Sixty mice were randomly divided into control group, model group and low-dose Sirolimus group, medium-dose and high-dose Sirolimus groups.Prevention and therapeutic administration were used in the Sirolimus low, medium and high dose groups.One week before model establishment, intraperitoneal injection of Sirolimus 1 mg/kg, 3 mg/kg and 9 mg/kg were given once a day, but the model group and the control group were injected intra-peritoneally the same dose of 9 g/L saline.One week after the preventive administration, all mice except the control group, were intraperitoneally injected 30 mg/kg kainate solution, and the control group was injected an equal dose of 9 g/L saline.Mice were treated 1 week after the establishment of the models.The number of mice with epileptic symptoms and the number of epileptic seizures, the seizure time and the average number of episodes were recorded, the Morris water maze test was performed on the mice, and the arrival time, swimming distance and number of crossing times of the mice were collected.The expression levels of mTOR pathway-related protein gene and the number of apoptotic cells in hippocampus were detected in hippocampus of mice. Results Epilepsy symptoms appeared earlier in the model group after modeling, and the epileptoid-like symptoms were significantly delayed in each group (P=0.001 9). The epilepsy grading model group was significantly higher than that of other groups.The mouse seizure time on the 6th day after modeling was significantly higher than that on the 3rd day after modeling.The time required for the model epileptic mouse to reach the platform and the swimming length was significantly more than that of the control group (P=0.000 1), while the number of the mice traversing the platform was significantly lower (P=0.000 2), and the admi-nistration group was significantly relieved.The gene expression levels of mTOR pathway key proteins mTOR and S6 in the hippocampus of mice in the model group were significantly up-regulated (P=0.000 1). Simultaneously, different doses of Sirolimus could significantly down-regulate PI3K, AKT, mTOR, and S6 gene expression levels (P=0.000 1). Compared with the control group, the gray ratios of p-PI3K, p-AKT, p-mTOR and p-S6 and normal PI3K, AKT, mTOR and S6 protein in the model group were significantly higher (P=0.000 1), and Sirolimus was also observed.It was significantly down-regulated after administration (P=0.000 1). Conclusions Sirolimus can significantly inhibit the over-activation of mTOR signaling pathway in the hippocampal region of kainic acid-induced epilepsy mice, thereby alleviating the symptoms of epilepsy in mice and increasing learning and memory. Key words: Sirolimus; mTOR signaling pathway; Kainic acid; Epilepsy

Triheptanoin alters [U-13C6]-glucose incorporation into glycolytic intermediates and increases TCA cycling by normalizing the activities of pyruvate dehydrogenase and oxoglutarate dehydrogenase in a chronic epilepsy mouse model

Triheptanoin is anticonvulsant in several seizure models. Here, we investigated changes in glucose metabolism by triheptanoin interictally in the chronic stage of the pilocarpine mouse epilepsy model. After injection of [U-13C6]-glucose (i.p.), enrichments of 13C in intermediates of glycolysis and the tricarboxylic acid (TCA) cycle were quantified in hippocampal extracts and maximal activities of enzymes in each pathway were measured. The enrichment of 13C glucose in plasma was similar across all groups. Despite this, we observed reductions in incorporation of 13C in several glycolytic intermediates compared to control mice suggesting glucose utilization may be impaired and/or glycogenolysis increased in the untreated interictal hippocampus. Triheptanoin prevented the interictal reductions of 13C incorporation in most glycolytic intermediates, suggesting it increased glucose utilization or – as an additional astrocytic fuel – it decreased glycogen breakdown. In the TCA cycle metabolites, the incorporation of 13C was reduced in the interictal state. Triheptanoin restored the correlation between 13C enrichments of pyruvate relative to most of the TCA cycle intermediates in “epileptic” mice. Triheptanoin also prevented the reductions of hippocampal pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase activities. Decreased glycogen breakdown and increased glucose utilization and metabolism via the TCA cycle in epileptogenic brain areas may contribute to triheptanoin's anticonvulsant effects.

Bioinformatics Analysis of Microarray Profiling Identifies That the miR-203-3p Target Ppp2ca Aggravates Seizure Activity in Mice.

This study aimed to identify key genes (microRNA and messenger RNA (mRNA)) and associated signaling-regulated pathways in a drug-induced epilepsy model in mice by microarray profiling. The related microarray dataset of seizures was obtained from the NCBI Gene Expression Omnibus database (GEO), and differentially expressed genes (DEGs) between two control samples or multi-treated samples and samples were analyzed using the statistical software R. To identify the expected function of DEGs, Gene Set Enrichment Analysis (GSEA) was utilized to conduct Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The interaction relationship between microRNAs (miRNAs) and mRNAs in normal and epilepsy mouse models was identified using Cytoscape software. TargetScan7.1 was applied to determine the binding sites of DEGs. The dual-luciferase assay was used to verify the target relationship between miRNA and mRNA. Four miRNAs were identified as differentially expressed genes in both 24-h and 28-day status epilepticus (SE)-treated samples. Ppp2ca expression in the mitogen-activated protein kinase (MAPK) signaling pathway was downregulated in the pilocarpine-induced SE mouse model. The expression of Ppp2ca was also downregulated in the kinase-induced SE model group compared with that in the untreated group and MAP kinase (MEK) inhibitor-treated group of mice. KEGG pathway analysis indicated that the MAPK signaling pathway was upregulated in the kinase-induced SE model group compared with that in both the untreated group and the MEK inhibitor-treated group of mice. miR-203 had a targeted relationship with Ppp2ca in both humans and mice. The miR-203-3p target Ppp2ca aggravates the seizures of the SE model in mice.

Compensatory Mechanisms Modulate the Neuronal Excitability in a Kainic Acid-Induced Epilepsy Mouse Model.

Epilepsy is one of the most common neurological disorders affecting millions of people. Due to the complicated and unclear mechanisms of epilepsy, still a significant proportion of epilepsy patients remain poorly controlled. Epilepsy is characterized by convulsive seizures that are caused by increased excitability. In this study, by using kainic acid (KA)-induced epilepsy mice, we investigated the neuronal activities and revealed the neuronal compensatory mechanisms after KA-induced toxic hyperexcitability. The results indicate that both phasic inhibition induced by enhanced inhibitory synaptic activity and tonic inhibition mediated by activated astrocytes participate in the compensatory mechanisms. Compensatory mechanisms were already found in various neuronal disorders and were considered important in protecting nervous system from toxic hyperexcitability. This study hopefully will provide valuable clues in understanding the complex neuronal mechanisms of epilepsy, and exploring potential clinical treatment of the disease.

Effects of Honokiol on cognitive function in mice with kainic acid-induced epilepsy

To investigate the effects of Honokiol on cognitive function in mice with epilepsy. Kainic acid (38 mg/kg) was intraperitoneally injected in 5 weeks old male ICR mice to induce epilepsy. Honokiol at dose of 3, 10, 30 mg/kg was given to epilepic mice by intraperitoneal injection for 10 days. Fluoro-Jade B staining was used to assess neuronal death; Morris water maze and Y maze tests were used to measure cognitive function such as learning and memory; Western blot was performed to detect the expression of acetylated superoxide dismutase (SOD), microtubule associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ) and P62 in hippocampus tissue; thiobarbituric acid and WST-1 methods were used to detect malondialdehyde (MDA) and SOD. Compared with control group, the levels of acetylated-SOD, MDA, LC3-Ⅱ, P62 and neuronal death increased, cognitive function and SOD decreased in model group (P<0.05 or P<0.01). Honokiol at the dose of 10 mg/kg and 30 mg/kg decreased SOD acetylation, MDA content, expression of LC3-Ⅱ and P62, as well as neuronal death, and the cognitive function was improved (P<0.05 or P<0.01), especially in 30 mg/kg Honokiol group. Honokiol alleviates oxidative stress and autophagy degradation disorder, decreases neuronal death, and therefore improves cognitive function in epilepsy mice.

Dysregulated long non-coding RNAs in the temporal lobe epilepsy mouse model

PurposeTo perform comprehensive profiling of long non-coding RNAs (LncRNAs) in temporal lobe epilepsy. MethodsWe performed extensive profiling of LncRNAs and mRNAs in the mouse pilocarpine model in specific brain regions, the hippocampus and cortex, and compared the results to those of the control mouse. Differentially expressed LncRNAs and mRNAs were identified with a microarray analysis (Arraystar Mouse LncRNA Expression Microarray V3.0). Then, gene ontology (GO) and pathway analysis were performed to investigate the potential roles of the differentially expressed mRNAs in the pilocarpine model. Protein-protein interactions transcribed by dysregulated mRNAs with/without co-dysregulated LncRNAs were analyzed using STRING v10 (http://string-db.org/). ResultsA total of 22 and 83 LncRNAs were up- and down-regulated (≥2.0-fold, all P < .05), respectively, in the hippocampus of the epilepsy model, while 46 and 659 LncRNAs were up- and down-regulated, respectively, in the cortex of the epilepsy model. GO and pathway analysis revealed that the dysregulated mRNAs were closely associated with a process already known to be involved in epileptogenesis: acute inflammation, calcium ion regulation, extracellular matrix remodeling, and neuronal differentiation. Among the LncRNAs, we identified 10 LncRNAs commonly dysregulated with corresponding mRNAs in the cortex. The STRING analysis showed that the dysregulated mRNAs were interconnected around two centers: the mTOR pathway-related genes and REST pathway-related genes. ConclusionLncRNAs were dysregulated in the pilocarpine mouse model according to the brain regions of the hippocampus and cortex. The dysregulated LncRNAs with co-dysregulated mRNAs might be possible therapeutic targets for the epigenetic regulation of chronic epilepsy.

MicroRNA-421 suppresses the apoptosis and autophagy of hippocampal neurons in epilepsy mice model by inhibition of the TLR/MYD88 pathway.

Epilepsy is a group of neurological disorders characterized by epileptic seizures. In this study, we aim to explore the role of microRNA-421 (miR-421) in hippocampal neurons of epilepsy mice via the TLR/MYD88 pathway. Forty mice were randomly served as the normal and model (established as epilepsy model) groups. Hippocampal neurons were assigned into seven groups with different transfections. The RT-qPCR and western blotting were conducted to examine the expression of miR-421 TLR2, TLR4, MYD88, Bax, Bcl-2, p53, Beclin-1, and LC3II/LC3I. Cell proliferation and apoptosis were detected by MTT and flow cytometry.MYD88 is a target gene of miR-421. Model mice showed elevated expression of TLR2, TLR4, MYD88, Bax, p53, Beclin-1, and LC3II/LC3I but reduced expression of miR-421 and Bcl-2. In vitro experiments reveals that overexpression of miR-421 inhibited the TLR/MYD88 pathway. Besides, overexpressed miR-421 declined cell apoptosis but increased cell proliferation. It reveals that miR-421 targeting MYD88 could inhibit the apoptosis and autophagy of hippocampal neurons in epilepsy mice by down-regulating the TLR/MYD88 pathway.

Geniposide attenuates epilepsy symptoms in a mouse model through the PI3K/Akt/GSK-3β signaling pathway.

Previous reports on the pharmacological actions of geniposide have indicated that it has anti-asthmatic, anti-inflammatory and analgesic effects in the liver and gallbladder, and therapeutic effects in neurological, cardiovascular and cerebrovascular diseases. The results of the current study demonstrate that geniposide attenuates epilepsy in a mouse model through the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) signaling pathway. A mouse model of epilepsy was induced by maximal electric shock (50 mA, 50 Hz, 1 sec). Epilepsy mice were intragastrically administered with 0, 5, 10 or 20 mg/kg geniposide. Geniposide significantly reduced the incidence and significantly increased the latency of clonic seizures in epileptic mice compared with non-treated epileptic mice (both P<0.01). Geniposide treatment significantly inhibited cyclooxygenase-2 mRNA expression in epilepsy mice (P<0.01). Furthermore, geniposide significantly suppressed the protein expression of activator protein 1, increased the activation of Akt and increased the protein expression of GSK-3β and PI3K in epilepsy mice (all P<0.01). These results suggest that geniposide attenuates epilepsy in mice through the PI3K/Akt/GSK-3β signaling pathway.

Dynamical properties of LFPs from mice with unilateral injection of TeNT

Local field potential (LFP) recordings were performed from the visual cortex (V1) of a focal epilepsy mouse model. Epilepsy was induced by a unilateral injection of the synaptic blocker tetanus neurotoxin (TeNT). LFP signals were simultaneously recorded from V1 of both hemispheres of each animal under acute and chronic conditions (i.e. during and after the period of TeNT action). All data were analysed by using nonlinear time series methods. Suitable values of the lag time and embedding dimension for phase space reconstruction were estimated by employing well-known methods. The results showed that lag times are sensitive to the presence of TeNT. Interestingly, TeNT promoted an increase in the level of linear and nonlinear correlation of LFP signals. The values of the embedding dimension failed to show any dependence on the presence of the neurotoxin. However, a local nonlinear prediction method showed that the presence of TeNT increases the predictability, quantified by the normalized prediction error, of the neural recordings. From a neurophysiological point of view, the above results suggest that TeNT injected in one hemisphere strongly impacts the local electrical activity of the neural populations in the opposite hemisphere. We hypothesize that this could arise from a qualitative and quantitative alteration of the transmission properties of the callosal fibers.

The effect of CXCR2 inhibition on seizure activity in the pilocarpine epilepsy mouse model.

C-X-C motif chemokine receptor 2 (CXCR2) is one of the most well characterized chemokine receptors and is a potential target for treating brain pathologies involving inflammatory processes, including epilepsy. However, the role of CXCR2 in epilepsy has not been investigated, and whether CXCR2 modulates seizure activity in temporal lobe epilepsy (TLE) remains unknown. In this study, we aimed to determine the potential role of CXCR2 in intractable TLE patients and in pilocarpine-induced epileptic mice. Here, through Western blotting and semi-quantitative immunohistochemistry, we detected that CXCR2 protein expression was up-regulated (by nearly 50%) in the temporal neocortex of TLE patients and in the hippocampus and adjacent temporal cortex of pilocarpine mice model. Double-label immunofluorescence and immunohistochemical analysis indicated that CXCR2 was expressed in neurons. To investigate the effect of the CXCR2 selective antagonist SB225002 on seizure activity, SB225002 was i.p. administered during the latency window of spontaneous recurrent seizures (SRSs). This treatment increased (by nearly 40%) the latency of SRSs and reduced (by nearly 50%) the frequency of SRSs during the chronic period of epilepsy. This study suggests that CXCR2 plays a critical role in modifying epileptic seizure activity and that CXCR2 blockade could be a potential molecular therapeutic target for epilepsy.

Cacna1g is a genetic modifier of epilepsy in a mouse model of Dravet syndrome.

Dravet syndrome, an early onset epileptic encephalopathy, is most often caused by de novo mutation of the neuronal voltage-gated sodium channel gene SCN1A. Mouse models with deletion of Scn1a recapitulate Dravet syndrome phenotypes, including spontaneous generalized tonic-clonic seizures, susceptibility to seizures induced byelevated body temperature, and elevated risk of sudden unexpected death in epilepsy. Importantly, the epilepsy phenotype of Dravet mouse models is highly strain-dependent, suggesting a strong influence of genetic modifiers. We previously identified Cacna1g, encoding the Cav3.1 subunit of the T-type calcium channel family, as an epilepsy modifier in the Scn2aQ54 transgenic epilepsy mouse model. In this study, we asked whether transgenic alteration of Cacna1g expression modifies severity of the Scn1a+/- Dravet phenotype. Scn1a+/- mice with decreased Cacna1g expression showed partial amelioration of disease phenotypes with improved survival and reduced spontaneous seizure frequency. However, reduced Cacna1g expression did not alter susceptibility to hyperthermia-induced seizures. Transgenic elevation of Cacna1g expression had no effect on the Scn1a+/- epilepsy phenotype. These results provide support for Cacna1g as a genetic modifier in a mouse model of Dravet syndrome and suggest that Cav3.1 may be a potential molecular target for therapeutic intervention in patients.