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 three pre-clinical 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. CRAFT is applicable to disease settings other than epilepsy.

Frigerio et al. report that pro-resolving mechanisms of neuroinflammation are dysregulated during epileptogenesis, thereby promoting a persistent neuroinflammatory response that contributes to seizure generation and cognitive deficits. Boosting endogenous resolution responses by administering a specific lipid mediator improves disease outcomes in a murine epilepsy model, suggesting a novel treatment avenue.

In classical MTS1A, the expression of SV2 isoforms is altered with a marked decrease of SV2A and SV2B paralleling synaptic loss and a selective increase of SV2C in sprouting mossy fibres. These findings suggest a different physiology of sprouting synapses and the possibility to target them with SV2C-specific strategies.

Many antiepileptic drugs (AEDs) exert their therapeutic activity by modifying the inactivation properties of voltage-gated sodium (Na(v) ) channels. Lacosamide is unique among AEDs in that it selectively enhances the slow inactivation component. Although numerous studies have investigated the effects of AEDs on Na(v) channel inactivation, a direct comparison of results cannot be made because of varying experimental conditions. In this study, the effects of different AEDs on Na(v) channel steady-state slow inactivation were investigated under identical experimental conditions using whole-cell patch-clamp in N1E-115 mouse neuroblastoma cells. All drugs were tested at 100 μM, and results were compared with those from time-matched control groups. Lacosamide significantly shifted the voltage dependence of Na(v) current (I(Na) ) slow inactivation toward more hyperpolarized potentials (by -33 ± 7 mV), whereas the maximal fraction of slow inactivated channels and the curve slope did not differ significantly. Neither SPM6953 (lacosamide inactive enantiomer), nor carbamazepine, nor zonisamide affected the voltage dependence of I(Na) slow inactivation, the maximal fraction of slow inactivated channels, or the curve slope. Phenytoin significantly increased the maximal fraction of slow inactivated channels (by 28% ± 9%) in a voltage-independent manner but did not affect the curve slope. Lamotrigine slightly increased the fraction of inactivated currents (by 15% ± 4%) and widened the range of the slow inactivation voltage dependence. Lamotrigine and rufinamide induced weak, but significant, shifts of I(Na) slow inactivation toward more depolarized potentials. The effects of lacosamide on Na(v) channel slow inactivation corroborate previous observations that lacosamide has a unique mode of action among AEDs that act on Na(v) channels.

BackgroundSV2A, SV2B and SV2C are synaptic vesicle proteins that are structurally related to members of the major facilitator superfamily (MFS). The function and transported substrate of the SV2 proteins is not clearly defined although they are linked to neurotransmitters release in a presynaptic calcium concentration-dependent manner. SV2A and SV2B exhibit broad expression in the central nervous system while SV2C appears to be more restricted in defined areas such as striatum. SV2A knockout mice start to display generalized seizures at a late developmental stage, around post-natal day 7 (P7), and die around P15. More recently, SV2A was demonstrated to be the molecular target of levetiracetam, an approved anti-epileptic drug (AED). The purpose of this work was to precisely analyze and quantify the SV2A, SV2B and SV2C expression during brain development to understand the contribution of these proteins in brain development and their impact on epileptic seizures.ResultsFirst, we systematically analyzed by immunohistofluorescence, the SV2A, SV2B and SV2C expression during mouse brain development, from embryonic day 12 (E12) to P30. This semi-quantitative approach suggests a modulation of SV2A and SV2B expression in hippocampus around P7. This is the reason why we used various quantitative approaches (laser microdissection of whole hippocampus followed by qRT-PCR and western blot analysis) indicating that SV2A and SV2B expression increased between P5 and P7 and remained stable between P7 and P10. Moreover, the increase of SV2A expression in the hippocampus at P7 was mainly observed in the CA1 region while SV2B expression in this region remains stable.ConclusionsThe observed alterations of SV2A expression in hippocampus are consistent with the appearance of seizures in SV2A−/− animals at early postnatal age and the hypothesis that SV2A absence favors epileptic seizures around P7.

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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.

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