Target For Antiepileptic Drugs Research Articles

WHAT ADVANCEMENTS IN CLINICAL NEUROSCIENCES NEED TO OCCUR IN THE NEXT 10 YEARS?

Introduction: Temporal lobe epilepsy (TLE) is the commonest focal epilepsy. Acquired TLE is considered to occur as the result of a 3-phase process called epileptogenesis. Firstly, an ‘epileptogenic event’ occurs, for example traumatic brain injury. Next follows a latent period whereby hyperexcitable networks form and lower the seizure threshold. Finally, TLE emerges. The objective of this review is to investigate how gene dysregulation drives hyperexcitability during epileptogenesis. Methods: Searches were conducted using keywords and medical subject headings on bibliographic databases and complemented by Google searches and manual revision of reference lists of retrieved articles. Results: Multiple pathogenic processes occur during the latent phase of epileptogenesis, before acquired TLE is diagnosed. These are hippocampal sclerosis, synaptic reorganisation including mossy fibre sprouting, neuroinflammation, aberrant neurogenesis and astrogliosis. Furthermore, epigenetic signalling pathways including DNA methylation, histone modifications, transcriptional and post-transcriptional dysregulation drive these pathogenic brain changes. Discussion: The epigenetic pathways that drive pathogenic brain changes following epileptogenic events are potential therapeutic targets for novel antiepileptic drugs. Targeting molecular pathways could prevent many cases of acquired TLE by halting epileptogenesis in the latent phase, meaning new therapies for acquired TLE have the potential to be antiepileptogenic rather than simply anticonvulsant.

Computer-aided identification of human carbonic anhydrase isoenzyme VII inhibitors as potential antiepileptic agents

Human carbonic anhydrase (hCA) belongs to a superfamily of metalloenzymes that reversibly catalyse the hydration of carbon dioxide to give bicarbonate (HCO3 −) and proton (H+). As HCO3 − ions play an important role in neuronal signalling hence, hCA enzymes are an attractive target for antiepileptic drugs. Out of all the isoforms, hCA VII is predominantly expressed in the brain cortex and hippocampus region, which are the most affected area during seizure activity. Hence, we have identified some hCA VII inhibitors employing computational tools like atom-based 3D quantitative structure–activity relationship (QSAR), auto-QSAR, pharmacophore-based virtual screening, molecular docking, and molecular dynamics (MD) simulations. Atom-based 3D QSAR modelling outperformed auto-QSAR with an R 2 and Q 2 value of 0.9634 and 0.9646, respectively. A four-feature pharmacophore model (AADR_1) was developed and a focussed library of around 3,00,000 compounds was screened. Compounds with a phase screen score >2.40 were selected for docking studies. The activity of the selected hits was predicted employing the developed 3D QSAR model. Finally, three compounds were taken up for the MD simulation studies which also suggest that the identified hits might form a stable complex with hCA VII enzyme. A comparative docking study was also done with other hCA isoforms like I, II, IV, IX, and XII to examine the selectivity of the identified hits towards hCA VII. Based on these studies, three hits have been identified as potential hCA VII inhibitor which is drug-like molecules. Further, in vitro studies are required to develop leads from these identified hits. Communicated by Ramaswamy H. Sarma

Identification of the ZEB2 gene as a potential target for epilepsy therapy and the association between rs10496964 and ZEB2 expression

ObjectiveAn association between the rs10496964 polymorphism and the ZEB2 gene has not yet been reported, and the role of ZEB2 in epilepsy therapy is also unclear. The aims of this research were to evaluate the role of ZEB2 in the therapy of epilepsy and to explore the association between rs10496964 and ZEB2 expression.MethodsWe used the expression quantitative trait loci (eQTL) dataset resource from the Brain eQTL Almanac to evaluate the association between rs10496964 and ZEB2 expression in human brain tissue. Pathway and process enrichment analysis, protein–protein interaction analysis, and PhosphoSitePlus® analysis were then performed to further evaluate the role of ZEB2 in the therapy of epilepsy.ResultsThe rs10496964 polymorphism was found to regulate the expression of ZEB2 in human brain tissue. The ZEB2 protein interacts with the targets of approved antiepileptic drugs, and a post-translational acetylation modification of ZEB2 was associated with an epilepsy drug therapy.ConclusionOur findings suggest that ZEB2 may be involved in the therapy of epilepsy, and rs10496964 regulates ZEB2 expression in human brain tissue.

Structural basis of AMPA receptor inhibition by trans-4-butylcyclohexane carboxylic acid.

AMPA receptors, which shape excitatory postsynaptic currents and are directly involved in overactivation of synaptic function during seizures, represent a well-accepted target for anti-epileptic drugs. Trans-4-butylcyclohexane carboxylic acid (4-BCCA) has emerged as a new promising anti-epileptic drug in several in vitro and in vivo seizure models, but the mechanism of its action remained unknown. The purpose of this study is to characterize structure and dynamics of 4-BCCA interaction with AMPA receptors. We studied the molecular mechanism of AMPA receptor inhibition by 4-BCCA using a combination of X-ray crystallography, mutagenesis, electrophysiological assays, and molecular dynamics simulations. We identified 4-BCCA binding sites in the transmembrane domain (TMD) of AMPA receptor, at the lateral portals formed by transmembrane segments M1-M4. At this binding site, 4-BCCA is very dynamic, assumes multiple poses, and can enter the ion channel pore. 4-BCCA represents a low-affinity inhibitor of AMPA receptors that acts at the TMD sites distinct from non-competitive inhibitors, such as the anti-epileptic drug perampanel and the ion channel blockers. Further studies might examine the possibsility of synergistic use of these inhibitors in treatment of epilepsy and a wide range of neurological disorders and gliomas. This article is part of a themed issue on Structure Guided Pharmacology of Membrane Proteins (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.14/issuetoc.

Two for the Price of One: Heterobivalent Ligand Design Targeting Two Binding Sites on Voltage-Gated Sodium Channels Slows Ligand Dissociation and Enhances Potency.

Voltage-gated sodium (NaV) channels are pore-forming transmembrane proteins that play essential roles in excitable cells, and they are key targets for antiepileptic, antiarrhythmic, and analgesic drugs. We implemented a heterobivalent design strategy to modulate the potency, selectivity, and binding kinetics of NaV channel ligands. We conjugated μ-conotoxin KIIIA, which occludes the pore of the NaV channels, to an analogue of huwentoxin-IV, a spider-venom peptide that allosterically modulates channel gating. Bioorthogonal hydrazide and copper-assisted azide–alkyne cycloaddition conjugation chemistries were employed to generate heterobivalent ligands using polyethylene glycol linkers spanning 40–120 Å. The ligand with an 80 Å linker had the most pronounced bivalent effects, with a significantly slower dissociation rate and 4–24-fold higher potency compared to those of the monovalent peptides for the human NaV1.4 channel. This study highlights the power of heterobivalent ligand design and expands the repertoire of pharmacological probes for exploring the function of NaV channels.

Voltage-dependent anion channels mediated apoptosis in refractory epilepsy.

The purpose of this study was to investigate the role of voltage-dependent anion channel (VDAC) in mitochondria-mediated apoptosis of neurons in refractory epilepsy. Western blot analyses were carried out to detect the changes in cytochrome C, caspase 9, Bax, and Bcl-2. TUNEL assays were also carried out to investigate cell apoptosis under the upregulation and downregulation of VDAC1 with or without Bax or Bcl-2. VDAC1 induced Bax, Bcl-2, and caspase 9, increasing the release of cytochrome C. VDAC1 played an essential role in the apoptotic cell death of refractory epilepsy. It is concluded that VDAC1 plays an important role in refractory epilepsy and could be a possible therapeutic target of anti-epileptic drugs. The current study provides a new understanding of the possible mechanisms of refractory epilepsy.

AJAP1 affects behavioral changes and GABABR1 level in epileptic mice

Adherens junction-associated protein-1 (AJAP1), also called SHREW1, was first discovered as a novel component of adherens junctions in 2004. In later studies, AJAP1 was found to suppress invasion and predict recurrence of some tumors. Apart from its function as a putative tumor suppressor, AJAP1 is still poorly understood. Schwenk et al. recently found that AJAP1 was tightly associated with the γ-Aminobutyric acid type B receptor subunit 1(GABABR1). It is well known that GABABR plays a vital role in epilepsy as an inhibitory transmitter receptor. Structurally adjacent, possibly functionally interacting, therefore, we hypothesize that AJAP1 participates in the onset and progression of epilepsy. We designed this experiment to investigate the expression and location of AJAP1 in temporal lobe epilepsy (TLE) patients and kainic acid(KA)-induced epilepsy animal models by immunofluorescence and Western blot analyses. We overexpressed and inhibited AJAP1 through lentiviruses in KA-induced models and observed the corresponding effects on epileptic animals. Double-label immunofluorescence showed that AJAP1 was expressed mainly in neurons. Western blot analysis revealed that AJAP1 expression was downregulated in the neocortex of TLE patients and the hippocampus and neocortex of epileptic animal models. The overexpression of AJAP1 can reduce the frequency of spontaneous seizures, whereas the inhibition of AJAP1 expression can increase the incidence rate. Our study demonstrated that AJAP1 may be involved in the pathogenic process of epilepsy and may represent a novel antiepileptic target.

Electrostatic Interactions of Negatively Charged DHAA Derivatives with the Voltage-Gated Potassium Channel Kv7.2/7.3

Many patients with epilepsy do not respond to existing pharmaceutical treatment, so there is a large need of new types of antiepileptic drugs. The voltage dependent M-type potassium current activates and deactivates slowly and is important to set the resting potential and to reduce repetitive firing of neurons. This current is generated by an ion channel composed of Kv7.2 and 7.3 subunits. Some inherited forms of epilepsy are caused by mutations in the genes coding for these subunits, and the Kv7.2/7.3 channel is a validated target for antiepileptic drugs. Today, there is no Kv7.2/7.3 channel-opening drug on the market. Our goal is to develop a Kv7.2/7.3-channel opening compound. Recently, our group designed a set of molecules, based on the structure of dehydroabietic acid (DHAA), that open the Shaker Kv channel from Drosophila melanogaster. We showed that he charge of the carboxyl group of the DHAA derivatives as well as potitively charged amino-acid residues of the channel's voltage sensor are required for the compounds to open the channel. In previous experiments we showed that DHAA-derivatives at concentrations as low as 0.3 μM open of the human hKv7.2/7.3 channel but it is not known if the mechanism is the same as for the Shaker Kv channel. Here we explored if the same mechanism is valid for the hKv7.2/7.3 channel expressed in Xenopus oocytes. To explore the role of the charge of the carboxyl group we tested the effect of the compounds at different pH. To explore the role of the charges of the voltage sensor S4 we systematically mutated the extracellular end of S4. Overall, the mechanism of DHAA derivatives on the hKv7.2/7.3 channel is the same as for the Shaker Kv channel, but there are quantitative differences.

Selective hyperactivation of JNK2 in an animal model of temporal lobe epilepsy

c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family and are derived from three genes, Jnk1-3. These kinases are involved in cellular responses to homeostatic insults, such as inflammation and apoptosis. Furthermore, increased JNK expression and activation are associated with debilitating neurodegenerative diseases, including Alzheimer’s and Parkinson’s. We previously reported elevated levels of phosphorylated JNK (pJNK), indicative of JNK hyperactivation, in the CA1 hippocampus of chronically epileptic rats. We also showed that pharmacological inhibition of JNK activity reduced seizure frequency in a dose-dependent fashion (Tai TY et al., Neuroscience, 2017). Building on these observations, the objectives of this current study were to investigate the timeline of JNK activation during epileptogenesis, and to identify the JNK isoform(s) that undergo hyperactivation in the chronic epilepsy stage. Western blotting analysis of CA1 hippocampal homogenates showed JNK hyperactivation only during the chronic phase of epilepsy (6–9 weeks post-status epilepticus), and not in earlier stages of epileptogenesis (1 h, 1 day, and 1 week post-status epilepticus). After enrichment for pJNK by immunoprecipitation, we identified JNK2 as the only significantly hyperactivated JNK isoform, with expression of the 54 kDa pJNK2 variant elevated to a greater extent than the 46 kDa pJNK2 variant. Expression of the total amounts of both JNK2 variants (phosphorylated plus non-phosphorylated) was reduced in epilepsy, however, suggesting that activation of upstream phosphorylation pathways was responsible for JNK2 hyperactivation. Since our prior work demonstrated that pharmacological inhibition of JNK activation had an antiepileptic effect, JNK2 hyperactivation is therefore likely a pathological event that promotes seizure occurrences. This investigation provides evidence that JNK2 is selectively hyperactivated in epilepsy and thus may be a novel and selective antiepileptic target.

Inhibition of USP15 Prevent Glutamate-Induced Oxidative Damage by Activating Nrf2/HO-1 Signaling Pathway in HT22 Cells.

Oxidative stress has been identified as the significant mediator in epilepsy, which is a chronic disorder in central nervous system. About 30% of epilepsy patients are refractory to antiepileptic drug treatment. However, the underlying mechanism of oxidative damage in epilepsy needs further investigation. In our study, we first find that ubiquitin-specific peptidase 15 (USP15) expression was upregulated in a pentylenetetrazole (PTZ) kindled rat model of epilepsy. Silencing USP15 protected against glutamate-mediated neuronal cell death, and inhibited the high expression levels of cleaved caspase-3. Knockout of USP15 significantly reduced intracellular reactive oxygen species (ROS) levels and enhanced superoxide dismutase (SOD) activity in HT22 cells under the exposure to glutamate treatment. Furthermore, USP15 inhibition induced nuclear factor erythroid-derived 2-related factor2 (Nrf2) nuclear translocation and promoted protein expression level of heme oxygenase (HO-1). Taken together, our findings first reveal a role of USP15 in the pathogenesis of epilepsy, and silencing USP15 in vitro protects against glutamate-mediated cytotoxicity in HT22 cells. Pharmacological inhibition of USP15 may alleviate epileptic seizures via fighting against oxidative damage, providing a novel antiepileptic target.

Intestinal inflammation increases convulsant activity and reduces antiepileptic drug efficacy in a mouse model of epilepsy

We studied the effects of intestinal inflammation on pentylenetetrazole (PTZ)-induced seizures in mice and the effects thereon of some antiepileptic and anti-inflammatory treatments to establish if a link may exist. The agents tested were: alpha-lactoalbumin (ALAC), a whey protein rich in tryptophan, effective in some animal models of epilepsy and on colon/intestine inflammation, valproic acid (VPA), an effective antiepileptic drug in this seizure model, mesalazine (MSZ) an effective aminosalicylate anti-inflammatory treatment against ulcerative colitis and sodium butyrate (NaB), a short chain fatty acid (SCFA) normally produced in the intestine by gut microbiota, important in maintaining gut health and reducing gut inflammation and oxidative stress. Intestinal inflammation was induced by dextran sulfate sodium (DSS) administration for 6 days. Drug treatment was started on day 3 and lasted 11 days, when seizure susceptibility to PTZ was measured along with intestinal inflammatory markers (i.e. NF-κB, Iκ-Bα, COX-2, iNOS), histological damage, disease activity index (DAI) and SCFA concentration in stools. DSS-induced colitis increased seizure susceptibility and while all treatments were able to reduce intestinal inflammation, only ALAC and NaB exhibited significant antiepileptic properties in mice with induced colitis, while they were ineffective as antiepileptics at the same doses in control mice without colitis. Interestingly, in DSS-treated mice, VPA lost part of its antiepileptic efficacy in comparison to preventing seizures in non-DSS-treated mice while MSZ remained ineffective in both groups. Our study demonstrates that reducing intestinal inflammation through ALAC or NaB administration has specific anticonvulsant effects in PTZ-treated mice. Furthermore, it appears that intestinal inflammation may reduce the antiepileptic effects of VPA, although we confirm that it decreases seizure threshold in this group. Therefore, we suggest that intestinal inflammation may represent a valid antiepileptic target which should also be considered as a participating factor to seizure incidence in susceptible patients and also could be relevant in reducing standard antiepileptic drug efficacy.

Insights into the mechanisms of epilepsy from structural biology of LGI1-ADAM22.

Epilepsy is one of the most common brain disorders, which can be caused by abnormal synaptic transmissions. Many epilepsy-related mutations have been identified in synaptic ion channels, which are main targets for current antiepileptic drugs. One of the novel potential targets for therapy of epilepsy is a class of non-ion channel-type epilepsy-related proteins. The leucine-rich repeat glioma-inactivated protein 1 (LGI1) is a neuronal secreted protein, and has been extensively studied as a product of a causative gene for autosomal dominant lateral temporal lobe epilepsy (ADLTE; also known as autosomal dominant partial epilepsy with auditory features [ADPEAF]). At least 43 mutations of LGI1 have been found in ADLTE families. Additionally, autoantibodies against LGI1 in limbic encephalitis are associated with amnesia, seizures, and cognitive dysfunction. Although the relationship of LGI1 with synaptic transmission and synaptic disorders has been studied genetically, biochemically, and clinically, the structural mechanism of LGI1 remained largely unknown until recently. In this review, we introduce insights into pathogenic mechanisms of LGI1 from recent structural studies on LGI1 and its receptor, ADAM22. We also discuss the mechanism for pathogenesis of autoantibodies against LGI1, and the potential of chemical correctors as novel drugs for epilepsy, with structural aspects of LGI1-ADAM22.

The Positive Allosteric Modulator of Alpha-2/3-Containing γ-Aminobutyric Acid Type A Receptors, KRM-II-81, Is Active in Pharmacoresistant Models of Epilepsy and in Human Epileptic Tissue

Abstract INTRODUCTION Epilepsy patients continue to suffer from the lack of efficacious medications. Recent attention has been directed toward the potential advantages of developing positive allosteric modulators of alpha-2/3-containing γ-aminobutyric acid type A (GABAA) receptors as antiepileptic drugs. A proof of principle has been reported with one such molecule in patients with photosensitive epilepsy. KRM-II-81 (5- (8-ethynyl-6- (pyridin-2-yl)-4H-benzo[f]imidazole[1,5-alpha][1,4]diazepin-3-yl)oxazole) is an orally-bioavailable compound recently designed for selectivity at alpha-2/3-containing GABAA receptors over the alpha-1-subtype involved in motor-impairing effects. KRM-II-81 has recently been reported to dampen seizure activity in rodents induced by acute and chronic seizure provocation. KRM-II-81 was often more efficacious than diazepam as an anticonvulsant while producing less motor impairment than diazepam. The reduced motor impact of KRM-II-81 is hypothesized to enable higher central target exposure and hence increased efficacy. METHODS The effects of KRM-II-81 were investigated in a mouse mesial temporal lobe model and a rat lamotrigine-resistant kindling model. We also explored the antiepileptic electrophysiological effects of KRM-II-81 in cortical slices from epileptic pediatric patients to help guide the development of novel compounds that might be valuable against antiepileptic drug-resistant epilepsies. RESULTS Mice with kainate-induced mesial temporal lobe seizures exhibited spontaneous recurrent hippocampal paroxysmal discharges (16.8 +/–2.5). KRM-II-81 significantly reduced the discharge frequency to 5.5 +/–1.4 after oral dosing at 15 mg/kg. KRM-II-81 also decreased convulsions in rats undergoing amygdala kindling in the presence of lamotrigine. In slices of epileptic cortex, KRM-II-81 produced a concentration-dependent dampening of network activity engendered by the GABAA receptor antagonist picrotoxin or the K+-channel modulator 4-aminopyridine. CONCLUSION This study provides increased levels of confidence regarding the unique anticonvulsant profile of KRM-II-81 and its potential as an improved antiepileptic drug. The data also help to solidify the veracity of alpha-2/3-containing GABAA receptors as a novel molecular target for antiepileptic drugs.

CRAFTing a New Approach to Antiepileptic Drug Discovery.

Srivastava PK, van Eyll J, Godard P, Mazzuferi M, Delahaye-Duriez A, Steenwinckel JV, et al. A systems-level framework for drug discovery identifies Csf1R as an anti-epileptic drug target. Nat Commun. 2018;9(1):3561. doi:10.1038/s41467-018-06008-4.The identification of drug targets is highly challenging, particularly for diseases of the brain. To address this problem, we developed and experimentally validated a general computational framework for drug target discovery that combines gene regulatory information with causal reasoning (“Causal Reasoning Analytical Framework for Target discovery”-CRAFT). Using a systems genetics approach and starting from gene expression data from the target tissue, CRAFT provides a predictive framework for identifying cell membrane receptors with a direction-specified influence over disease-related gene expression profiles. As proof of concept, we applied CRAFT to epilepsy and predicted the tyrosine kinase receptor Csf1R as a potential therapeutic target. The predicted effect of Csf1R blockade in attenuating epilepsy seizures was validated in 3 preclinical models of epilepsy. These results highlight CRAFT as a systems-level framework for target discovery and suggest Csf1R blockade as a novel therapeutic strategy in epilepsy. The CRAFT is applicable to disease settings other than epilepsy.

Ketone Bodies Inhibit the Opening of Acid-Sensing Ion Channels (ASICs) in Rat Hippocampal Excitatory Neurons in vitro.

Objectives: Despite the long-term efficacy of antiepileptic drug treatments, frequent attacks of drug-resistant epilepsy necessitate the development of new antiepileptic drug therapy targets. The ketogenic diet is a high-fat, low-carbohydrate diet that has been shown to be effective in treating drug-resistant epilepsy, although the mechanism is yet unclear. In the ketogenic diet, excess fat is metabolized into ketone bodies (including acetoacetic acid, β-hydroxybutyric acid, and acetone). The present study explored the effect of ketone bodies on acid-sensing ion channels and provided a theoretical basis for the study of new targets of antiepileptic drugs based on “ketone body-acid sensing ion channels.”Methods: In this study, rat primary cultured hippocampal neurons were used. The effects of acetoacetic acid, β-hydroxybutyric acid, and acetone on the open state of acid-sensing ion channels of hippocampal neurons were investigated by the patch-clamp technique.Results: At pH 6.0, the addition of acetoacetic acid, β-hydroxybutyric acid, and acetone in the extracellular solution markedly weakened the currents of acid-sensing ion channels. The three ketone bodies significantly inhibited the opening of the acid-sensing ion channels on the surface of the hippocampal neurons, and 92, 47, and 77%, respectively.Conclusions: Ketone bodies significantly inhibit the opening of acid-sensing ion channels. However, a new target for antiepileptic drugs on acid-sensing ion channels is yet to be investigated.

Structure based virtual screening of novel noncompetitive antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor

The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype ionotropic glutamate receptors are attractive antiepileptic targets responsible for mediating the majority of excitatory neurotransmission and plasticity. The noncompetitive antagonists obtain more and more attention as drug candidates for treatment of the neurological diseases involving excessive activity of AMPARs, due to they regulate AMPA receptors (AMPARs) activity independently of endogenous glutamate levels unlike the competitive antagonists. Development of novel AMPAR noncompetitive antagonists, which are safer and more efficacious than competitive antagonists, is highly under demand. Here, we present the discovery of novel antagonists against AMPAR through Structure-Based Virtual Screening (SBVS). Three compounds were successfully distinguished by several different filtering strategies, namely STOCK6S-10902, STOCK1N-49134 and STOCK5S-68665. The interaction mode of these compounds was further explored through molecular dynamics simulation, binding free energy calculation and the binding free energy decomposition. It is demonstrated that some residues within the binding pocket, which have been proved their importance in antagonist binding and gating, form strong hydrogen bond interactions with these three molecules. In particular, H-bond interactions with high occupancies between Ser516, Ser788 and STOCK6S-10902 and Ser516, Asn791 and STOCK1N-49134 were observed. The three hit compounds with new scaffolds and the detailed binding modes could potentially serve as a starting point for further optimization and development.

Genome-wide mega-analysis identifies 16 loci and highlights diverse biological mechanisms in the common epilepsies

The epilepsies affect around 65 million people worldwide and have a substantial missing heritability component. We report a genome-wide mega-analysis involving 15,212 individuals with epilepsy and 29,677 controls, which reveals 16 genome-wide significant loci, of which 11 are novel. Using various prioritization criteria, we pinpoint the 21 most likely epilepsy genes at these loci, with the majority in genetic generalized epilepsies. These genes have diverse biological functions, including coding for ion-channel subunits, transcription factors and a vitamin-B6 metabolism enzyme. Converging evidence shows that the common variants associated with epilepsy play a role in epigenetic regulation of gene expression in the brain. The results show an enrichment for monogenic epilepsy genes as well as known targets of antiepileptic drugs. Using SNP-based heritability analyses we disentangle both the unique and overlapping genetic basis to seven different epilepsy subtypes. Together, these findings provide leads for epilepsy therapies based on underlying pathophysiology.

Traditional remedy points to epilepsy target

For people with epilepsy, managing seizures is critical to protect themselves and others. Yet up to one-third of people with epilepsy—15 million to 20 million worldwide—don’t respond to medications. Now, by examining a traditional Congolese remedy for epilepsy, researchers have found support for a novel protein target for seizure-controlling medication (ACS Chem. Neurosci. 2018, DOI:10.1021/acschemneuro.8b00281). If verified through clinical testing, it could lead to a more diversified tool kit for doctors and patients alike. “This research shows the potential of ethnomedicinal and traditional knowledge, which is often disregarded or even resisted by mainstream science,” says study coauthor Joelle N. Chabwine of the Salama Neuroscience Center, in the Democratic Republic of the Congo. The new work suggests that glycogen synthase kinase-3 (GSK-3), which regulates energy storage in the body, is a viable epilepsy drug target. Kinase inhibitors are unusual targets for antiepileptic drugs; this study represents...

GPR40 modulates epileptic seizure and NMDA receptor function.

Epilepsy is a common neurological disease, and approximately 30% of patients do not respond adequately to antiepileptic drug treatment. Recent studies suggest that G protein-coupled receptor 40 (GPR40) is expressed in the central nervous system and is involved in the regulation of neurological function. However, the impact of GPR40 on epileptic seizures remains unclear. In this study, we first reported that GPR40 expression was increased in epileptic brains. In the kainic acid-induced epilepsy model, GPR40 activation after status epilepticus alleviated epileptic activity, whereas GPR40 inhibition showed the opposite effect. In the pentylenetetrazole-induced kindling model, susceptibility to epilepsy was reduced with GPR40 activation and increased with GPR40 inhibition. Whole-cell patch-clamp recordings demonstrated that GPR40 affected N-methyl-d-aspartate (NMDA) receptor-mediated synaptic transmission. Moreover, GPR40 regulated NR2A and NR2B expression on the surface of neurons. In addition, endocytosis of NMDA receptors and binding of GPR40 with NR2A and NR2B can be regulated by GPR40. Together, our findings indicate that GPR40 modulates epileptic seizures, providing a novel antiepileptic target.

Epilepsy-on-a-Chip System for Antiepileptic Drug Discovery.

Hippocampal slice cultures spontaneously develop chronic epilepsy several days after slicing and are used as an in vitro model of post-traumatic epilepsy. Here, we describe a hybrid microfluidic-microelectrode array (μflow-MEA) technology that incorporates a microfluidic perfusion network and electrodes into a miniaturized device for hippocampal slice culture based antiepileptic drug discovery. Field potential simulation was conducted to help optimize the electrode design to detect a seizure-like population activity. Epilepsy-on-a-chip model was validated by chronic electrical recording, neuronal survival quantification, and anticonvulsant test. To demonstrate the application ofμflow-MEA in drug discovery, we utilized a two-stage screening platform to identify potential targets for antiepileptic drugs. In Stage I, lactate and lactate dehydrogenase biomarker assays were performed to identify potential drug candidates. In Stage II, candidate compounds were retested withμflow-MEA-based chronic electrical assay to provide electrophysiological confirmation of biomarker results. We screened 12 receptor tyrosine kinases inhibitors, and EGFR/ErbB-2 and cFMS inhibitors were identified as novel antiepileptic compounds. This epilepsy-on-a-chip system provides the means for rapid dissection of complex signaling pathways in epileptogenesis, paving the way for high-throughput antiepileptic drug discovery.