Summary Purpose:  Synaptic vesicle protein 2A (SV2A) constitutes a distinct binding site for an antiepileptic drug levetiracetam (Keppra). In the present study we characterized SV2A (+/−) heterozygous mice in several seizure models and tested if the anticonvulsant efficacy of levetiracetam is reduced in these mice. Methods:  Seizure thresholds of male SV2A (+/−) mice and their wild‐type littermates were assessed in pilocarpine (i.p.), kainic acid (s.c.), pentylenetetrazol (i.v.), 6‐Hz and maximal electroshock models. Kindling development was compared in amygdala and corneal kindling models. Ex vivo binding of levetiracetam to SV2A was also performed. Results:  Long‐term electroencephalography (EEG) monitoring and behavioral observations of SV2A (+/−) mice did not reveal any spontaneous seizure activity. However, a reduced seizure threshold of SV2A (+/−) mice was observed in pilocarpine, kainic acid, pentylenetetrazol, and 6‐Hz models, but not in maximal electroshock seizure model. Accelerated epileptogenesis development was also demonstrated in amygdala and corneal kindling models. Anticonvulsant efficacy of levetiracetam, defined as its ability to increase seizure threshold for 6 Hz electrical stimulation, was significantly reduced (approx. 50%) in the SV2A (+/−) mice, consistently with reduced binding to SV2A in these mice. In contrast, valproate produced the same anticonvulsant effect in both SV2A (+/+) and SV2A (+/−) mice. Discussion: The present results evidence that SV2A is involved in mediation of the in vivo anticonvulsant activity of levetiracetam, in accordance with its previously proposed mechanism of action. Furthermore, the present data also indicate that even partial SV2A deficiency may lead to increased seizure vulnerability and accelerated epileptogenesis.

The use of impedance-based label-free technology applied to drug discovery is nowadays receiving more and more attention. Indeed, such a simple and noninvasive assay that interferes minimally with cell morphology and function allows one to perform kinetic measurements and to obtain information on proliferation, migration, cytotoxicity, and receptor-mediated signaling. The objective of the study was to further assess the usefulness of a real-time cell analyzer (RTCA) platform based on impedance in the context of quality control and data reproducibility. The data indicate that this technology is useful to determine the best coating and cellular density conditions for different adherent cellular models including hepatocytes, cardiomyocytes, fibroblasts, and hybrid neuroblastoma/neuronal cells. Based on 31 independent experiments, the reproducibility of cell index data generated from HepG2 cells exposed to DMSO and to Triton X-100 was satisfactory, with a coefficient of variation close to 10%. Cell index data were also well reproduced when cardiomyocytes and fibroblasts were exposed to 21 compounds three times (correlation >0.91, p < 0.0001). The data also show that a cell index decrease is not always associated with cytotoxicity effects and that there are some confounding factors that can affect the analysis. Finally, another drawback is that the correlation analysis between cellular impedance measurements and classical toxicity endpoints has been performed on a limited number of compounds. Overall, despite some limitations, the RTCA technology appears to be a powerful and reliable tool in drug discovery because of the reasonable throughput, rapid and efficient performance, technical optimization, and cell quality control.

Epilepsy affects around 50 million people worldwide, and in about 65 % of patients, the etiology of disease is unknown. MicroRNAs are small non-coding RNAs that have been suggested to play a role in the pathophysiology of epilepsy. Here, we compared microRNA expression patterns in the hippocampus using two chronic models of epilepsy characterised by recurrent spontaneous seizures (pilocarpine and self-sustained status epilepticus (SSSE)) and an acute 6-Hz seizure model. The vast majority of microRNAs deregulated in the acute model exhibited increased expression with 146 microRNAs up-regulated within 6 h after a single seizure. In contrast, in the chronic models, the number of up-regulated microRNAs was similar to the number of down-regulated microRNAs. Three microRNAs—miR-142-5p, miR-331-3p and miR-30a-5p—were commonly deregulated in all three models. However, there is a clear overlap of differentially expressed microRNAs within the chronic models with 36 and 15 microRNAs co-regulated at 24 h and at 28 days following status epilepticus, respectively. Pathway analysis revealed that the altered microRNAs are associated with inflammation, innate immunity and cell cycle regulation. Taken together, the identified microRNAs and the pathways they modulate might represent candidates for novel molecular approaches for the treatment of patients with epilepsy.Electronic supplementary materialThe online version of this article (doi:10.1007/s12031-014-0368-6) contains supplementary material, which is available to authorized users.

Levetiracetam (LEV) is a new antiepileptic drug with a promising preclinical profile involving both anticonvulsant and antiepileptogenic effects in kindling models. The latter stimulated the present study to compare its neuroprotective properties with the potent and selective, non-competitive NMDA antagonist, MK-801, in the rat middle cerebral artery occlusion model. Twenty-four hours after a transient occlusion of 90 minutes the animals were sacrificed and infarct volume and lesion distribution were determined from stained coronal sections. LEV was administered by intraperitoneal (i.p.) bolus injections of 5.5, 11, 22 and 44 mg x kg(-1), 30 minutes before occlusion followed by a continuous 24 hour i.p. infusion of 1.25, 2.6, 5.1 and 10.2 mg x kg(-1) per hour, respectively. LEV administration did not alter body temperature but reduced the infarct volume by 33% (P< 0.05) at the highest dose tested. An i.p. bolus injection of 0.04, 0.12 and 0.4 mg x kg(-1) of MK-801 followed by continuous i.p. infusion of 0.036, 0.108 and 0.36 mg x kg(-1) per hour, reduced the infarct volume by 49, 51 and 74% (P< 0.05), respectively. However, only the highest dose of MK-801 induced a significant reduction in the infarct volume (P< 0.05) and this was associated with hypothermia. These results suggest that LEV possesses neuroprotective properties which may be relevant for its antiepileptogenic action.

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Understanding the mechanisms of epileptogenesis is essential to develop novel drugs that could prevent or modify the disease. Neuroinflammation has been proposed as a promising target for therapeutic interventions to inhibit the epileptogenic process that evolves from traumatic brain injury. However, it remains unclear whether cytokine-related pathways, particularly TNFα signaling, have a critical role in the development of epilepsy. In this study, we investigated the role of innate inflammation in an in vitro model of post-traumatic epileptogenesis. We combined organotypic hippocampal slice cultures, representing an in vitro model of post-traumatic epilepsy, with multi-electrode array recordings to directly monitor the development of epileptiform activity and to examine the concomitant changes in cytokine release, cell death, and glial cell activation. We report that synchronized ictal- and interictal-like activities spontaneously evolve in this culture. Dynamic changes in the release of the pro-inflammatory cytokines IL-1β, TNFα, and IL-6 were observed throughout the culture period (3 to 21 days in vitro) with persistent activation of microglia and astrocytes. We found that neutralizing TNFα with a polyclonal antibody significantly reduced ictal discharges, and this effect lasted for 1 week after antibody washout. Neither phenytoin nor an anti-IL-6 polyclonal antibody was efficacious in inhibiting the development of epileptiform activity. Our data show a sustained effect of the anti-TNFα antibody on the ictal progression in organotypic hippocampal slice cultures supporting the critical role of inflammatory mediators in epilepsy and establishing a proof-of-principle evidence for the utility of this preparation to test the therapeutic effects of anti-inflammatory treatments.Electronic supplementary materialThe online version of this article (10.1007/s13311-018-0607-6) contains supplementary material, which is available to authorized users.

AimsBrivaracetam (BRV) is an antiepileptic drug in Phase III clinical development. BRV binds to synaptic vesicle 2A (SV2A) protein and is also suggested to inhibit voltage-gated sodium channels (VGSCs). To evaluate whether the effect of BRV on VGSCs represents a relevant mechanism participating in its antiepileptic properties, we explored the pharmacology of BRV on VGSCs in different cell systems and tested its efficacy at reducing the sustained repetitive firing (SRF).MethodsBrivaracetam investigations on the voltage-gated sodium current (INa) were performed in N1E-155 neuroblastoma cells, cultured rat cortical neurons, and adult mouse CA1 neurons. SRF was measured in cultured cortical neurons and in CA1 neurons. All BRV (100–300 μM) experiments were performed in comparison with 100 μM carbamazepine (CBZ).ResultsBrivaracetam and CBZ reduced INa in N1E-115 cells (30% and 40%, respectively) and primary cortical neurons (21% and 47%, respectively) by modulating the fast-inactivated state of VGSCs. BRV, in contrast to CBZ, did not affect INa in CA1 neurons and SRF in cortical and CA1 neurons. CBZ consistently inhibited neuronal SRF by 75–93%.ConclusionsThe lack of effect of BRV on SRF in neurons suggests that the reported inhibition of BRV on VGSC currents does not contribute to its antiepileptic properties.

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