Neuromodulatory role of endogenous interleukin-1β in acute seizures: possible contribution of cyclooxygenase-2

PLPP/CIN-mediated NF2 S10 dephosphorylation distinctly regulates kainate-induced seizure susceptibility and neuronal death through PAK1-NF-κB-COX-2-PTGES2 signaling pathway

BACKGROUND

Pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) selectively dephosphorylates serine (S) 10 site on neurofibromin 2 (NF2, also known as merlin (moesin-ezrin-radixin-like protein) or schwannomin). p21-activated kinase 1 (PAK1) is a serine/threonine protein kinase, which is involved in synaptic activity and plasticity in neurons. NF2 and PAK1 reciprocally regulate each other in a positive feedback manner. Thus, the aim of the present study is to investigate the effects of PLPP/CIN-mediated NF2 S10 dephosphorylation on PAK1-related signaling pathways under physiological and neuroinflammatory conditions, which are largely unknown.

METHODS

After kainate (KA) injection in wild-type, PLPP/CIN^-/- and PLPP/CIN^Tg mice, seizure susceptibility, PAK1 S204 autophosphorylation, nuclear factor-κB (NF-κB) p65 S276 phosphorylation, cyclooxygenase-2 (COX-2) upregulation, prostaglandin E synthase 2 (PTGES2) induction and neuronal damage were measured. The effects of 1,1'-dithiodi-2-naphthtol (IPA-3, a selective inhibitor of PAK1) pretreatment on these responses to KA were also validated.

RESULTS

PLPP/CIN overexpression increased PAK1 S204 autophosphorylation concomitant with the enhanced NF2 S10 dephosphorylation in hippocampal neurons under physiological condition. Following KA treatment, PLPP/CIN overexpression delayed the seizure on-set and accelerated PAK1 S204 phosphorylation, NF-κB p65 S276 phosphorylation, COX-2 upregulation and PTGES2 induction, which were ameliorated by PLPP/CIN deletion or IPA-3. Furthermore, IPA-3 pretreatment shortened the latency of seizure on-set without affecting seizure severity (intensity) and ameliorated CA3 neuronal death induced by KA.

CONCLUSIONS

These findings indicate that PLPP/CIN may regulate seizure susceptibility (the latency of seizure on-set) and CA3 neuronal death in response to KA through NF2-PAK1-NF-κB-COX-2-PTGES2 signaling pathway.

The Cannabinoid Receptor Agonist, WIN-55212-2, Suppresses the Activation of Proinflammatory Genes Induced by Interleukin 1 Beta in Human Astrocytes

Background: Alterations of astrocyte function play a crucial role in neuroinflammatory diseases due to either the loss of their neuroprotective role or the gain of their toxic inflammatory properties. Accumulating evidence highlights that cannabinoids and cannabinoid receptor agonists, such as WIN55,212-2 (WIN), reduce inflammation in cellular and animal models. Thus, the endocannabinoid system has become an attractive target to attenuate chronic inflammation in neurodegenerative diseases. However, the mechanism of action of WIN in astrocytes remains poorly understood. Objective: We studied the immunosuppressive property of WIN by examining gene expression patterns that were modulated by WIN in reactive astrocytes. Materials and Methods: Transcriptomic analysis by RNA-seq was carried out using primary human astrocyte cultures stimulated by the proinflammatory cytokine interleukin 1 beta (IL1β) in the presence or absence of WIN. Real-time quantitative polymerase chain reaction analysis was conducted on selected transcripts to characterize the dose-response effects of WIN, and to test the effect of selective antagonists of cannabinoid receptor 1 (CB1) and peroxisome proliferator-activated receptors (PPAR). Results: Transcriptomic analysis showed that the IL1β-induced inflammatory response is robustly inhibited by WIN pretreatment. WIN treatment alone also induced substantial gene expression changes. Pathway analysis revealed that the anti-inflammatory properties of WIN were linked to the regulation of kinase pathways and gene targets of neuroprotective transcription factors, including PPAR and SMAD (mothers against decapentaplegic homolog). The inhibitory effect of WIN was dose-dependent, but it was not affected by selective antagonists of CB1 or PPAR. Conclusions: This study suggests that targeting the endocannabinoid system may be a promising strategy to disrupt inflammatory pathways in reactive astrocytes. The anti-inflammatory activity of WIN is independent of CB1, suggesting that alternative receptors mediate the effects of WIN. These results provide mechanistic insights into the anti-inflammatory activity of WIN and highlight that astrocytes are a potential therapeutic target to ameliorate neuroinflammation in the brain.

Beneficial Effects of Ibuprofen on Pentylenetetrazol-induced Convulsion

Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that is commonly used as an anti-inflammatory, anti-pyretic, and analgesic. Although some studies have focused on the anti-inflammatory and anti-pyretic properties of ibuprofen during febrile convulsions, only one has investigated its antiepileptic effects. In the present study, we aimed to investigate the effects of ibuprofen in rats exposed to pentylenetetrazol (PTZ)-induced seizures. In total, 48 rats were randomly divided in two groups: Group A for electroencephalography (EEG) recordings and Group B for behavioral assessment. All EEG recordings and behavioral assessment protocols were performed. In addition, groups were compared in terms of prostaglandin F2 alfa (PGF2α) levels in the brain. We demonstrated the beneficial effects of the administration of ibuprofen in PTZ-induced seizures in rats via the following findings: spike percentages and Racine convulsion scale values were significantly lower and first myoclonic jerk (FMJ) onset times were significantly higher in the ibuprofen-administered groups. Moreover, PGF2α levels in the brain were significantly higher in the saline and PTZ 70 mg/kg group than in the control and PTZ 70 mg/kg and 400 mg/kg ibuprofen groups. Our study is the first to demonstrate the beneficial effects of ibuprofen on seizures through behavioral, EEG, and PGF2α brain assessments. Ibuprofen can be used for epilepsy and febrile seizures safely and without inducing seizures. However, further experimental and clinical studies are needed to confirm our results.

Heroin vaccine: Using titer, affinity, and antinociception as metrics when examining sex and strain differences

Anti-drug vaccines have potential as new interventions against substance use disorder (SUD). However, given the challenges seen with inter-individual variability in SUD vaccine trials to date, new interventions should ensure a robust immune response and safety profile among a diverse population. This requires accounting for sex and heritable genetic differences in response to both abused substances as well as the vaccination itself. To test response variability to our heroin-tetanus toxoid (Her-TT) immunoconjugate vaccine, we vaccinated male and female mice from several mouse strains including Swiss Webster (SW), BALB/c, and Jackson diversity mice (J:DO). Previous studies with vaccinated male SW mice demonstrated a rare hypersensitivity resulting in mice rapidly expiring with exposure to a low dose of heroin. Our results indicate that this response is limited to only male SW mice, and not to any other strain or female SW mice. Our data suggest that this hypersensitivity is not the result of an overactive cytokine or IgE response. Vaccination was similarly effective among the sexes for each strain and against repeated heroin challenge. Inbred BALB/c and J:DO mice were found to have the best vaccine response against heroin in antinociception behavioral assay. These results highlight the importance of incorporating both male and female subjects, along with different strains to mimic diverse human populations, as new SUD vaccines are being tested.

Investigating the role of interleukin-1 beta and glutamate in inflammatory bowel disease and epilepsy using discovery browsing

BACKGROUND

Structured electronic health records are a rich resource for identifying novel correlations, such as co-morbidities and adverse drug reactions. For drug development and better understanding of biomedical phenomena, such correlations need to be supported by viable hypotheses about the mechanisms involved, which can then form the basis of experimental investigations.

METHODS

In this study, we demonstrate the use of discovery browsing, a literature-based discovery method, to generate plausible hypotheses elucidating correlations identified from structured clinical data. The method is supported by Semantic MEDLINE web application, which pinpoints interesting concepts and relevant MEDLINE citations, which are used to build a coherent hypothesis.

RESULTS

Discovery browsing revealed a plausible explanation for the correlation between epilepsy and inflammatory bowel disease that was found in an earlier population study. The generated hypothesis involves interleukin-1 beta (IL-1 beta) and glutamate, and suggests that IL-1 beta influence on glutamate levels is involved in the etiology of both epilepsy and inflammatory bowel disease.

CONCLUSIONS

The approach presented in this paper can supplement population-based correlation studies by enabling the scientist to identify literature that may justify the novel patterns identified in such studies and can underpin basic biomedical research that can lead to improved treatments and better healthcare outcomes.

Carvacrol mitigates proconvulsive effects of lipopolysaccharide, possibly through the hippocampal cyclooxygenase-2 inhibition

Systemic injection of LPS changes neuronal excitability and increase susceptibility for convulsions. Carvacrol exerts neuroprotective and antiepileptic effects in animal models. Herein, we investigated the anticonvulsive effect of carvacrol on LPS induced seizure severity and possible involvement of the hippocampal COX-1 and -2 activities in this effect. Adult male wistar rats were used. LPS was injected (400 μg/kg; i.p.) four hours before the PTZ (80 mg/kg; i.p.) injection. Carvacrol was injected (100 mg/kg; i.p.) immediately after the LPS injection. Following the PTZ injection, behavioral seizures were observed for 30 min. Latency and duration for each stage were recorded for analysis. Rats divided into seven groups: (1) PTZ, (2) LPS + PTZ, (3) carvacrol + PTZ, (4) LPS + carvacrol + PTZ, (5) LPS, (6) carvacrol, (7) intact. At the end of the experimental procedure the hippocampus of all animals were extracted to measure COX- 1 and 2 levels using the ELISA. LPS injection four hours before the PTZ injection were significantly reduced latency to seizure stages 3-5 and increased duration of the stage 5 in compare with PTZ group (p < 0.05). Carvacrol significantly reduced these effects of LPS on seizure susceptibility (p < 0.05). However, injection of carvacrol alone before the PTZ injection did not significantly affect seizure indexes in compare with PTZ group. Additionally, LPS significantly increased hippocampal level COX-2 but not COX-1 (p < 0.01) and carvacrol significantly attenuates this effect of LPS (p < 0.001). Carvacrol prevents the proconvulsant effect of LPS possibly through the inhibition of the COX-2 increased activity.

Mice lacking L-12/15-lipoxygenase show increased mortality during kindling despite demonstrating resistance to epileptogenesis

Objective

Studies have addressed the potential involvement of L-12/15-lipoxygenases (LOs), a polyunsaturated fatty acid metabolizing enzyme, in experimental models of acute stroke and chronic neurodegeneration; however, none to our knowledge has explored its role in epilepsy development. Thus, this study characterizes the cell-specific expression of L-12/15 -LO in the brain and examines its contribution to epileptogenesis.

Methods

L-12/15-LO messenger RNA (mRNA) and protein expression and activity were characterized via polymerase chain reaction (PCR), immunocytochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. To assess its role in epileptogenesis, L-12/15 -LO-deficient mice and their wild-type littermates were treated with pentylenetetrazole (PTZ, ip) every other day for up to 43 days (kindling paradigm). The innate seizure threshold was assessed by the acute PTZ-induced seizure response of naive mice.

Results

L-12/15 -LO mRNA is expressed in hippocampal and cortical tissue from wild-type C57BL/6 mice. In addition, it is physically and functionally expressed by microglia, neurons, and brain microvessel endothelial cells, but not by astrocytes. Mice deficient in L-12/15 -LO were resistant to PTZ-induced kindling and demonstrated an elevated innate seizure threshold. Despite this, a significant increase in seizure-related mortality was observed during the kindling paradigm in L-12/15 -LO nulls relative to their wild-type littermates.

Significance

The present study is the first to detail the role of L-12/15-LO in the epileptogenic process. The results suggest that constitutive L-12/15-LO expression contributes to a lower innate set point for PTZ acute seizure generation, translating to higher rates of kindling acquisition. Nevertheless, increased seizure-related deaths in mice lacking activity of L-12/15-LO suggests that its products may influence endogenous mechanisms involved in termination of seizure activity.

Maintenance of the Innate Seizure Threshold by Cyclooxygenase-2 is Not Influenced by the Translational Silencer, T-cell Intracellular Antigen-1

Activity of neuronal cyclooxygenase-2 (COX-2), a primary source of PG synthesis in the normal brain, is enhanced by excitatory neurotransmission and this is thought to be involved in seizure suppression. Results herein showing that the incidence of pentylenetetrazole (PTZ)-induced convulsions is suppressed in transgenic mice overexpressing COX-2 in neurons support this notion. T-cell intracellular antigen-1 (TIA-1) is an mRNA binding protein that is known to bind to COX-2 mRNA and repress its translation in non-neuronal cell types. An examination of the expression profile of TIA-1 protein in the normal brain indicated that it is expressed broadly by neurons, including those that express COX-2. However, whether TIA-1 regulates COX-2 protein levels in neurons is not known. The purpose of this study was to test the possibility that deletion of TIA-1 increases basal COX-2 expression in neurons and consequently raises the seizure threshold. Results demonstrate that neither the basal nor seizure-induced expression profiles of COX-2 were altered in mice lacking a functional TIA-1 gene suggesting that TIA-1 does not contribute to regulation of COX-2 protein expression in neurons. The acute PTZ-induced seizure threshold was also unchanged in mice lacking TIA-1 protein, indicating that this RNA binding protein does not influence the innate seizure threshold. Nevertheless, the results raise the possibility that the level of neuronal COX-2 expression may be a determinant of the innate seizure threshold and suggest that a better understanding of the regulation of COX-2 expression in the brain could provide new insight into the molecular mechanisms that suppress seizure induction.

Changes in the content of fatty acids in CA1 and CA3 areas of the hippocampus of Krushinsky-Molodkina rats after single and fivefold audiogenic seizures

Audiogenic seizures (AS) are generalized seizures evoked by high frequency sounds. Since the hippocampus is involved in the generation and maintenance of seizures, the effect of AS on the composition and content of fatty acids in the CA1 and CA3 hippocampal areas of AS-susceptible Krushinsky-Molodkina (KM) rats on days 1, 3, and 14 after single and fivefold seizures were examined. The total content of all fatty acids in field СА1 was found to be lower compared with the control at all times of observation after both a single seizure or fivefold seizures. The total content of fatty acids in field СА3 decreased at all times of examination after a single seizure, whereas it remained unchanged on days 3 and 14 following five AS. The content of omega-3 fatty acids in both fields at all times of observation after a single seizure and fivefold AS did not significantly differ from that in intact animals. The absence of significant changes in the content of stearic and α-linolenic acids and a considerable decrease in the levels of palmitic, oleic, and eicosapentaenoic acids were common to both fields at all times after both a single seizure or fivefold AS. The changes in the content of fatty acids in the СА3 and СА1 fields of the brain of AS-susceptible rats indicate that fatty acids are involved in both the development of seizure activity and neuroprotective anticonvulsive processes.

Cyclooxygenase-2 inhibitors differentially attenuate pentylenetetrazol-induced seizures and increase of pro- and anti-inflammatory cytokine levels in the cerebral cortex and hippocampus of mice

Seizures increase prostaglandin and cytokine levels in the brain. However, it remains to be determined whether cyclooxygenase-2 (COX-2) derived metabolites play a role in seizure-induced cytokine increase in the brain and whether anticonvulsant activity is shared by all COX-2 inhibitors. In this study we investigated whether three different COX-2 inhibitors alter pentylenetetrazol (PTZ)-induced seizures and increase of interleukin-1β (IL-1β), interleukin-6 (IL-6), interferon-γ (INF-γ), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) levels in the hippocampus and cerebral cortex of mice. Adult male albino Swiss mice received nimesulide, celecoxib or etoricoxib (0.2, 2 or 20mg/kg in 0.1% carboxymethylcellulose (CMC) in 5% Tween 80, p.o.). Sixty minutes thereafter the animals were injected with PTZ (50mg/kg, i.p.) and the latency to myoclonic jerks and to generalized tonic-clonic seizures were recorded. Twenty minutes after PTZ injection animals were killed and cytokine levels were measured. PTZ increased cytokine levels in the cerebral cortex and hippocampus. While celecoxib and nimesulide attenuated PTZ -induced increase of proinflammatory cytokines in the cerebral cortex, etoricoxib did not. Nimesulide was the only COX-2 inhibitors that attenuated PTZ-induced seizures. This effect coincided with an increase of IL-10 levels in the cerebral cortex and hippocampus, constituting circumstantial evidence that IL-10 increase may be involved in the anticonvulsant effect of nimesulide.

Indomethacin treatment prior to pentylenetetrazole-induced seizures downregulates the expression of il1b and cox2 and decreases seizure-like behavior in zebrafish larvae

Background

It has been demonstrated that the zebrafish model of pentylenetetrazole (PTZ)-evoked seizures and the well-established rodent models of epilepsy are similar pertaining to behavior, electrographic features, and c-fos expression. Although this zebrafish model is suitable for studying seizures, to date, inflammatory response after seizures has not been investigated using this model. Because a relationship between epilepsy and inflammation has been established, in the present study we investigated the transcript levels of the proinflammatory cytokines interleukin-1 beta (il1b) and cyclooxygenase-2 (cox2a and cox2b) after PTZ-induced seizures in the brain of zebrafish 7 days post fertilization. Furthermore, we exposed the fish to the nonsteroidal anti-inflammatory drug indomethacin prior to PTZ, and we measured its effect on seizure latency, number of seizure behaviors, and mRNA expression of il1b, cox2b, and c-fos. We used quantitative real-time PCR to assess the mRNA expression of il1b, cox2a, cox2b, and c-fos, and visual inspection was used to monitor seizure latency and the number of seizure-like behaviors.

Results

We found a short-term upregulation of il1b, and we revealed that cox2b, but not cox2a, was induced after seizures. Indomethacin treatment prior to PTZ-induced seizures downregulated the mRNA expression of il1b, cox2b, and c-fos. Moreover, we observed that in larvae exposed to indomethacin, seizure latency increased and the number of seizure-like behaviors decreased.

Conclusions

This is the first study showing that il1b and cox-2 transcripts are upregulated following PTZ-induced seizures in zebrafish. In addition, we demonstrated the anticonvulsant effect of indomethacin based on (1) the inhibition of PTZ-induced c-fos transcription, (2) increase in seizure latency, and (3) decrease in the number of seizure-like behaviors. Furthermore, anti-inflammatory effect of indomethacin is clearly demonstrated by the downregulation of the mRNA expression of il1b and cox2b. Our results are supported by previous evidences suggesting that zebrafish is a suitable alternative for studying inflammation, seizures, and the effect of anti-inflammatory compounds on seizure suppression.

High-fat diet-induced obesity exacerbates kainic acid-induced hippocampal cell death

BACKGROUND

Obesity has deleterious effects on the brain, and metabolic dysfunction may exacerbate the outcomes of seizures and brain injuries. However, it is unclear whether obesity affects excitotoxicity-induced neuronal cell death. The purpose of this study was to investigate the effects of a high-fat diet (HFD) on neuroinflammation and oxidative stress in the hippocampus of kainic acid (KA)-treated mice.

RESULTS

Mice were fed with a HFD or normal diet for 8 weeks and then received a systemic injection of KA. HFD-fed mice showed hypercholesterolemia, insulin resistance, and hepatic steatosis. HFD-fed mice showed greater susceptibility to KA-induced seizures, an increased number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, neuroinflammation, and oxidative stress. Furthermore, we found that KA treatment increased HFD-induced calpain1, nuclear factor E2-related factor 2, and heme oxygenase-1 expression in the hippocampus.

CONCLUSIONS

These findings imply that complex mechanisms affected by obesity-induced systemic inflammation, neuroinflammation, ER stress, calcium overload, and oxidative stress may contribute to neuronal death after brain injury.

Homeostatic regulation of KCC2 activity by the zinc receptor mZnR/GPR39 during seizures

The aim of this study was to investigate the role of the synaptic metabotropic zinc receptor mZnR/GPR39 in physiological adaptation to epileptic seizures. We previously demonstrated that synaptic activation of mZnR/GPR39 enhances inhibitory drive in the hippocampus by upregulating neuronal K(+)/Cl(-) co-transporter 2 (KCC2) activity. Here, we first show that mZnR/GPR39 knockout (KO) adult mice have dramatically enhanced susceptibility to seizures triggered by a single intraperitoneal injection of kainic acid, when compared to wild type (WT) littermates. Kainate also substantially enhances seizure-associated gamma oscillatory activity in juvenile mZnR/GPR39 KO hippocampal slices, a phenomenon that can be reproduced in WT tissue by extracellular Zn(2+) chelation. Importantly, kainate-induced synaptic Zn(2+) release enhances surface expression and transport activity of KCC2 in WT, but not mZnR/GPR39 KO hippocampal neurons. Kainate-dependent upregulation of KCC2 requires mZnR/GPR39 activation of the Gαq/phospholipase C/extracellular regulated kinase (ERK1/2) signaling cascade. We suggest that mZnR/GPR39-dependent upregulation of KCC2 activity provides homeostatic adaptation to an excitotoxic stimulus by increasing inhibition. As such, mZnR/GPR39 may provide a novel pharmacological target for dampening epileptic seizure activity.

The Pro-inflammatory Cytokine Interleukin-1β is a Key Regulatory Factor for the Postictal Suppression in Mice

AIMS

The postictal suppression (PS) is a common and important period following an epileptic seizure but has not been well studied. This study was designed to determine whether interleukin-1β (IL-1β) is involved in the PS.

METHODS

The effects of IL-1β on the PS were tested in three independent seizure models induced by hippocampal kindling, maximal electroshock seizure (MES), and 4-aminopyridine, respectively.

RESULTS

IL-1R1 knockout or IL-1RA enhanced the seizure refractory phenomenon without influencing the baseline seizure threshold in intermittent MES model. IL-1β attenuated the seizure refractory phenomenon without affecting the severity of the preceding seizures in hippocampal kindling model, while IL-1RA enhanced it. Besides, IL-1β reduced the postictal EEG suppression period, while IL-1RA prolonged it. And IL-1β showed no further effect on the postictal EEG suppression and seizure refractory phenomenon in IL-1R1 knockout mice. In addition, 30 min after intrahippocampal injection of 4-aminopyridine, IL-1β increased the incidence of SE, while IL-1RA prolonged the intervals between recurrent seizures.

CONCLUSIONS

This study provides the first direct evidence that IL-1β is key regulatory factor for the PS, and its receptor IL-1R1 may be a potential target for adjuvant treatment of postictal problems.

Tonicity-responsive enhancer binding protein haplodeficiency attenuates seizure severity and NF-κB-mediated neuroinflammation in kainic acid-induced seizures

Kainic acid (KA)-induced seizures followed by neuronal death are associated with neuroinflammation and blood-brain barrier (BBB) leakage. Tonicity-responsive enhancer binding protein (TonEBP) is known as a transcriptional factor activating osmoprotective genes, and in brain, it is expressed in neuronal nuclei. Thus dysregulation of TonEBP may be involved in the pathology of KA-induced seizures. Here we used TonEBP heterozygote (+/-) mice to study the roles of TonEBP. Electroencephalographic study showed that TonEBP (+/-) mice reduced seizure frequency and severity compared with wild type during KA-induced status epilepticus. Immunohistochemistry and western blotting analysis showed that KA-induced neuroinflammation and BBB leakage were dramatically reduced in TonEBP (+/-) mice. Similarly, TonEBP-specific siRNA reduced glutamate-induced death in HT22 hippocampal neuronal cells. TonEBP haplodeficiency prevented KA-induced nuclear translocation of NF-κB p65 and attenuated inflammation. Our findings identify TonEBP as a critical regulator of neuroinflammation and BBB leakage in KA-induced seizures, which suggests TonEBP as a good therapeutic target.

Seizure susceptibility in immature brain due to lack of COX-2-induced PGF2α

The immature brain is prone to seizure; however, the mechanism underlying this vulnerability has not been clarified. Febrile seizure is common in young children, and the use of non-steroidal anti-inflammatory drugs for febrile seizure is not recommended. In previous studies, we established that prostaglandin (PG) F2α, a product of cyclooxygenase (COX), acts as an endogenous anticonvulsant in the adult mouse. Therefore, we assumed that COX-2 activity was involved with seizure susceptibility in early life. In the present study, immature mice (postnatal day 9) were far more prone to kainic acid (KA)-induced seizures than mature mice (after postnatal day 35). Seizure activity began later in immature mice, but was more severe and was unaffected by a potent COX inhibitor, indomethacin; in contrast, indomethacin aggravated seizure activity in mature mice. Immature mouse brains exhibited little basal COX-2 expression and little KA-induced COX-2 induction, while KA-induced COX-2 expression and PGF2α release were prominent in mature brains. During brain development, COX expression was increased and glycosylated in an age-dependent manner, which was necessary for COX enzyme activity. Intracisternal PGF2α administration also reduced KA-induced seizure activity and mortality. Taken together, low COX activity and the resulting deficiency of PGF2α may be an essential cause of increased seizure susceptibility in the immature brain.

Modulation of Immunity and the Inflammatory Response: A New Target for Treating Drug-resistant Epilepsy

Until recently, epilepsy medical therapy is usually limited to anti-epileptic drugs (AEDs). However, approximately 1/3 of epilepsy patients, described as drug-resistant epilepsy (DRE) patients, still suffer from continuous frequent seizures despite receiving adequate AEDs treatment of sufficient duration. More recently, with the remarkable progress of immunology, immunity and inflammation are considered to be key elements of the pathobiology of epilepsy. Activation of inflammatory processes in brain tissue has been observed in both experimental seizure animal models and epilepsy patients. Anti-inflammatory and immunotherapies also showed significant anticonvulsant properties both in clinical and in experimental settings. The above emerging evidence indicates that modulation of immunity and inflammatory processes could serve as novel specific targets to achieve potential anticonvulsant effects for the patients with epilepsy, especially DRE. Herein we review the recent evidence supporting the role of inflammation in the development and perpetuation of seizures, and also discuss the recent achievements in modulation of inflammation and immunotherapy applied to the treatment of epilepsy. Apart from medical therapy, we also discuss the influences of surgery, ketogenic diet, and electroconvulsive therapy on immunity and inflammation in DRE patients. Taken together, a promising perspective is suggested for future immunomodulatory therapies in the treatment of patients with DRE.

The immature dentate gyrus represents a shared phenotype of mouse models of epilepsy and psychiatric disease

OBJECTIVES

There is accumulating evidence to suggest psychiatric disorders, such as bipolar disorder and schizophrenia, share common etiologies, pathophysiologies, genetics, and drug responses with many of the epilepsies. Here, we explored overlaps in cellular/molecular, electrophysiological, and behavioral phenotypes between putative mouse models of bipolar disorder/schizophrenia and epilepsy. We tested the hypothesis that an immature dentate gyrus (iDG), whose association with psychosis in patients has recently been reported, represents a common phenotype of both diseases.

METHODS

Behaviors of calcium/calmodulin-dependent protein kinase II alpha (α-CaMKII) heterozygous knock-out (KO) mice, which are a representative bipolar disorder/schizophrenia model displaying iDG, and pilocarpine-treated mice, which are a representative epilepsy model, were tested followed by quantitative polymerase chain reaction (qPCR)/immunohistochemistry for mRNA/protein expression associated with an iDG phenotype. In vitro electrophysiology of dentate gyrus granule cells (DG GCs) was examined in pilocarpine-treated epileptic mice.

RESULTS

The two disease models demonstrated similar behavioral deficits, such as hyperactivity, poor working memory performance, and social withdrawal. Significant reductions in mRNA expression and immunoreactivity of the mature neuronal marker calbindin and concomitant increases in mRNA expression and immunoreactivity of the immature neuronal marker calretinin represent iDG signatures that are present in both mice models. Electrophysiologically, we have confirmed that DG GCs from pilocarpine-treated mice represent an immature state. A significant decrease in hippocampal α-CaMKII protein levels was also found in both models.

CONCLUSIONS

Our data have shown iDG signatures from mouse models of both bipolar disorder/schizophrenia and epilepsy. The evidence suggests that the iDG may, in part, be responsible for the abnormal behavioral phenotype, and that the underlying pathophysiologies in epilepsy and bipolar disorder/schizophrenia are strikingly similar.

Interleukin-1β in Central Nervous System Injury and Repair

Acute inflammation is a self-limiting, complex biological response mounted to combat pathogen invasion, to protect against tissue damage, and to promote tissue repair should it occur. However, unabated inflammation can be deleterious and contribute to injury and pathology. Interleukin-1β (IL-1β), a prototypical "pro-inflammatory" cytokine, is essential to cellular defense and tissue repair in nearly all tissues. With respect to brain, however, studies suggest that IL-1β has pleiotrophic effects. It acts as a neuromodulator in the healthy central nervous system (CNS), has been implicated in the pathogenic processes associated with a number of CNS maladies, but may also provide protection to the injured CNS. Here, we will review the physiological and pathophysiological functions of IL-1β in the central nervous system with regard to synaptic plasticity. With respect to disease, emphasis will be placed on stroke, epilepsy, Parkinson's disease and Alzheimer's disease where the ultimate injurious or reparative effects of IL-1β appear to depend on time, concentration and environmental milieu.