Welcome to the sixth EPITARGET newsletter!
In the 6th issue of the EPITARGET newsletter, we would like to update you about the latest EPITARGET meeting, EPITARGET awardees, EPITARGET publications as well as the upcoming epiXchange conference in Brussels May 2018.
Recent EPITARGET events
5th General Assembly Meeting in Warsaw, 11-13 October 2017
The EPITARGET Consortium met in October 2017 in Warsaw. The meeting was hosted by the EPITARGET partner Nencki Institute of Experimental Biology. At the meeting, all partners updated each other on the work done since the last meeting and discussed the next steps and potential challenges.
The meeting was held back-to-back with the 3rd EPITARGET Young Researchers’ Symposium during which the young investigators of EPITARGET got the chance to present their work in presentations as well as posters. The best oral presentation as well as the best poster were awarded by a committee of experts within the consortium nominated by the coordinator, Merab Kokaia.
to the top
Wolfgang Löscher (TiHo) has been awarded by the Epilepsy Foundation the 2018 Lifetime Accelerator award. The Lifetime Accelerator Award was established in 2012 to honour physicians, scientists, industry leaders, and other individuals who have demonstrated a lifelong commitment to bringing new therapies to people living with epilepsy. Lifetime Accelerator Award recipients are chosen by an independent committee of global thought leaders and clinical investigators in epilepsy and seizure therapy discovery and development.
The Accelerator Award will be presented on February 22, 2018 in San Francisco.
Heinz Beck (L&B) has been awarded the Research Recognition Award, Basic Science, from the American Epilepsy Society (AES) for his promising translational and basic science research during the society’s meeting in Washington on December 2, 2017. Founded in 1946, the AES is a medical and scientific society whose members are dedicated to advancing research and education for preventing, treating and curing epilepsy. It is an inclusive global forum where professionals from academia, private practice, not-for-profit, government and industry can learn, share and grow to eradicate epilepsy and its consequences.
The AES Research Recognition Awards distinguish scientists and clinicians whose research holds promise for improving our understanding and treatment of epilepsy
to the top
epiXchange conference 2018 - A community building event for epilepsy research
The epiXchange conference, co-organized by seven former and ongoing EU-funded research projects on epilepsy (EpiTarget, EpimiRNA, EpiStop, Desire, EpiCare, EpiPGX and epiXchange), will take place on 23 May 2018.
The aim is to disseminate project results and discuss the future of epilepsy research in the EU and worldwide. The event is organised according to five epilepsy research related themes: Biomarkers, Genetics, Therapeutics, Co-morbidities and Biobanks and databases. In connection to the event, a white paper on the future needs in epilepsy research is being drafted by members of the epiXchange projects. The event will include existing talks from top researchers in the field as well as a poster session. More information about the event will be available on the event website soon.
In connection to the conference, the European Commission together with epiXchange partners organise a workshop on 24 May 2017 to discuss main achievements, challenges, priorities in epilepsy research and to establish recommendations for a long-term strategy with a global approach.
to the top
EPITARGET publications - short summaries
Schidlitzki A, Twele F, Klee R, Waltl I, Römermann K, Bröer S , Meller S, Gerhauser I, Rankovic V, Li D, Brandt C, Bankstahl M, Töllner K, Löscher W. A combination of NMDA and AMPA receptor antagonists retards granule cell dispersion and epileptogenesis in a model of acquired epilepsy. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28939854) Sci Rep. 2017 Sep 22;7(1):12191
Epilepsy may arise following acute brain insults, but no treatments exist that prevent epilepsy in patients at risk. Here we examined whether a combination of two glutamate receptor antagonists, NBQX and ifenprodil, acting at different receptor subtypes, exerts antiepileptogenic effects in the intrahippocampal kainate mouse model of epilepsy. These drugs were administered over 5 days following kainate. Spontaneous seizures were recorded by video/EEG at different intervals up to 3 months. Initial trials showed that drug treatment during the latent period led to higher mortality than treatment after onset of epilepsy, and further, that combined therapy with both drugs caused higher mortality at doses that appear safe when used singly. We therefore refined the combined-drug protocol, using lower doses. Two weeks after kainate, significantly less mice of the NBQX/ifenprodil group exhibited electroclinical seizures compared to vehicle controls, but this effect was lost at subsequent weeks. The disease modifying effect of the treatment was associated with a transient prevention of granule cell dispersion and less neuronal degeneration in the dentate hilus. These data substantiate the involvement of altered glutamatergic transmission in the early phase of epileptogenesis. Longer treatment with NBQX and ifenprodil may shed further light on the apparent temporal relationship between dentate gyrus reorganization and development of spontaneous seizures.
Korotkov A, Mills JD, Gorter JA, van Vliet EA, Aronica E. Systematic review and meta-analysis of differentially expressed miRNAs in experimental and human temporal lobe epilepsy. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28912503) Sci Rep. 2017 Sep 14;7(1):11592
Temporal lobe epilepsy (TLE) is a common chronic neurological disease in humans. A number of studies have demonstrated differential expression of miRNAs in the hippocampus of humans with TLE and in animal models of experimental epilepsy. However, the dissimilarities in experimental design have led to largely discordant results across these studies. Thus, a comprehensive comparison is required in order to better characterize miRNA profiles obtained in various post-status epilepticus (SE) models. We therefore created a database and performed a meta-analysis of differentially expressed miRNAs across 3 post-SE models of epileptogenesis (electrical stimulation, pilocarpine and kainic acid) and human TLE with hippocampal sclerosis (TLE-HS). The database includes data from 11 animal post-SE studies and 3 human TLE-HS studies. A total of 378 differentially expressed miRNAs were collected (274 up-regulated and 198 down-regulated) and analyzed with respect to the post-SE model, time point and animal species. We applied the novel robust rank aggregation method to identify consistently differentially expressed miRNAs across the profiles. It highlighted common and unique miRNAs at different stages of epileptogenesis. The pathway analysis revealed involvement of these miRNAs in key pathogenic pathways underlying epileptogenesis, including inflammation, gliosis and deregulation of the extracellular matrix.
Simonato M , Iyengar S, Brooks-Kayal A, Collins S, Depaulis A, Howells DW, Jensen F, Liao J, Macleod MR, Patel M, Potschka H, Walker M, Whittemore V, Sena ES. Identification and characterization of outcome measures reported in animal models of epilepsy: Protocol for a systematic review of the literature-A TASK2 report of the AES/ILAE Translational Task Force of the ILAE. (https://www.ncbi.nlm.nih.gov/pubmed/?term=29105071) Epilepsia. 2017 Nov;58 Suppl 4:68-77
Current antiseizure therapy is ineffective in approximately one third of people with epilepsy and is often associated with substantial side effects. In addition, most current therapeutic paradigms offer treatment, but not cure, and no therapies are able to modify the underlying disease, that is, can prevent or halt the process of epileptogenesis or alleviate the cognitive and psychiatric comorbidities. Preclinical research in the field of epilepsy has been extensive, but unfortunately, not all the animal models being used have been validated for their predictive value. The overall goal of TASK2 of the AES/ILAE Translational Task Force is to organize and coordinate systematic reviews on selected topics regarding animal research in epilepsy. Herein we describe our strategy. In the first part of the paper we provide an overview of the usefulness of systematic reviews and meta-analysis for preclinical research and explain the essentials for their conduct. Then we describe in detail the protocol for a first systematic review, which will focus on the identification and characterization of outcome measures reported in animal models of epilepsy. The specific goals of this study are to define systematically the phenotypic characteristics of the most commonly used animal models, and to effectively compare these with the manifestations of human epilepsy. This will provide epilepsy researchers with detailed information on the strengths and weaknesses of epilepsy models, facilitating their refinement and future research. Ultimately, this could lead to a refined use of relevant models for understanding the mechanism(s) of the epilepsies and developing novel therapies.
Galanopoulou AS, French JA, O'Brien T, Simonato M. Harmonization in preclinical epilepsy research: A joint AES/ILAE translational initiative. (https://www.ncbi.nlm.nih.gov/pubmed/?term=29105072) Epilepsia. 2017 Nov;58 Suppl 4:7-9.
Among the priority next steps outlined during the first translational epilepsy research workshop in London, United Kingdom (2012), jointly organized by the American Epilepsy Society (AES) and the International League Against Epilepsy (ILAE), are the harmonization of research practices used in preclinical studies and the development of infrastructure that facilitates multicenter preclinical studies. The AES/ILAE Translational Task Force of the ILAE has been pursuing initiatives that advance these goals. In this supplement, we present the first reports of the working groups of the Task Force that aim to improve practices of performing rodent video-electroencephalography (vEEG) studies in experimental controls, generate systematic reviews of preclinical research data, and develop preclinical common data elements (CDEs) for epilepsy research in animals.
van Vliet EA, Aronica E, Vezzani A, Ravizza T. Neuroinflammatory pathways as treatment targets and biomarker candidates in epilepsy: emerging evidence from preclinical and clinical studies. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28977690) Neuropathol Appl Neurobiol. 2017 Oct 4.
Accumulating evidence indicates an important pathophysiological role of brain inflammation in epilepsy. In this review, we will provide an update of specific inflammatory pathways that have been proposed to be crucial in the underlying molecular mechanisms of epilepsy, including the interleukin-1 receptor/toll-like receptor signaling, cyclooxygenase-2, tumor necrosis factor-alpha, complement signaling and chemokines. Furthermore, by drawing on evidence from preclinical and clinical studies we will discuss the potential of these signaling pathways targets for novel therapeutic interventions that control drug-resistant seizures or have disease-modifying effects. Finally, we will assess the use of these inflammatory pathways as potential biomarkers for the development of epilepsy or to measure the effectiveness of therapeutic interventions.
van Vliet EA, Puhakka N, Mills JD, Srivastava PK, Johnson MR, Roncon P, Das Gupta S, Karttunen J, Simonato M, Lukasiuk K, Gorter JA, Aronica E, Pitkänen A. Standardization procedure for plasma biomarker analysis in rat models of epileptogenesis: Focus on circulating microRNAs. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28960286) Epilepsia. 2017 Dec;58(12):2013-2024
The World Health Organization estimates that globally 2.4 million people are diagnosed with epilepsy each year. In nearly 30% of these cases, epilepsy cannot be properly controlled by antiepileptic drugs. More importantly, treatments to prevent or modify epileptogenesis do not exist. Therefore, novel therapies are urgently needed. In this respect, it is important to identify which patients will develop epilepsy and which individually tailored treatment is needed. However, currently, we have no tools to identify the patients at risk, and diagnosis of epileptogenesis remains as a major unmet medical need, which relates to lack of diagnostic biomarkers for epileptogenesis. As the epileptogenic process in humans is typically slow, the use of animal models is justified to speed up biomarker discovery. We aim to summarize recommendations for molecular biomarker research and propose a standardized procedure for biomarker discovery in rat models of epileptogenesis. The potential of many phylogenetically conserved circulating noncoding small RNAs, including microRNAs (miRNAs), as biomarkers has been explored in various brain diseases, including epilepsy. Recent studies show the feasibility of detecting miRNAs in blood in both experimental models and human epilepsy. However, the analysis of circulating miRNAs in rodent models is challenging, which relates both to the lack of standardized sampling protocols and to analysis of miRNAs. We will discuss the issues critical for preclinical plasma biomarker discovery, such as documentation, blood and brain tissue sampling and collection, plasma separation and storage, RNA extraction, quality control, and RNA detection. We propose a protocol for standardization of procedures for discovery of circulating miRNA biomarkers in rat models of epileptogenesis. Ultimately, we hope that the preclinical standardization will facilitate clinical biomarker discovery for epileptogenesis in man.
Lehto LJ, Albors AA, Sierra A, Tolppanen L, Eberly LE, Mangia S, Nurmi A, Michaeli S, Gröhn O. Lysophosphatidyl Choline Induced Demyelination in Rat Probed by Relaxation along a Fictitious Field in High Rank Rotating Frame. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28824359) Front Neurosci. 2017 Aug 3;11:433
In this work a new MRI modality entitled Relaxation Along a Fictitious Field in the rotating frame of rank 4 (RAFF4) was evaluated in its ability to detect lower myelin content in lysophosphatidyl choline (LPC)-induced demyelinating lesions. The lesions were induced in two areas of the rat brain with either uniform or complex fiber orientations, i.e., in the corpus callosum (cc) and dorsal tegmental tract (dtg), respectively. RAFF4 showed excellent ability to detect demyelinated lesions and good correlation with myelin content in both brain areas. In comparison, diffusion tensor imaging metrices, fractional anisotropy, mean diffusivity and axonal and radial diffusivity, and magnetization transfer (MT) metrices, longitudinal relaxation during off-resonance irradiation and MT ratio, either failed to detect demyelination in dtg or showed lower correlation with myelin density quantified from gold chloride stained histological sections. Good specifity of RAFF4 to myelin was confirmed by its low correlation with cell density assesed from Nissl stained sections as well as its lack of sensitivity to pH changes in the physiological range as tested in heat denaturated bovine serum albumin phantoms. The excellent ability of RAFF4 to detect myelin content and its insensitivity to fiber orientation distribution, gliosis and pH, together with low specific absorption rate, demonstrates the promise of rotating frame of rank n (RAFFn) as a valuable MRI technique for non-invasive imaging of demyelinating lesions.
Broekaart DWM, van Scheppingen J, Geijtenbeek KW, Zuidberg MRJ, Anink JJ, Baayen JC, Mühlebner A, Aronica E, Gorter JA, van Vliet EA. Increased expression of (immuno)proteasome subunits during epileptogenesis is attenuated by inhibition of the mammalian target of rapamycin pathway. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28643873) Epilepsia. 2017 Aug;58(8):1462-1472
OBJECTIVE: Inhibition of the mammalian target of rapamycin (mTOR) pathway reduces epileptogenesis in various epilepsy models, possibly by inhibition of inflammatory processes, which may include the proteasome system. To study the role of mTOR inhibition in the regulation of the proteasome system, we investigated (immuno)proteasome expression during epileptogenesis, as well as the effects of the mTOR inhibitor rapamycin.
METHODS: The expression of constitutive (β1, β5) and immunoproteasome (β1i, β5i) subunits was investigated during epileptogenesis using immunohistochemistry in the electrical post-status epilepticus (SE) rat model for temporal lobe epilepsy (TLE). The effect of rapamycin was studied on (immuno)proteasome subunit expression in post-SE rats that were treated for 6 weeks. (Immuno)proteasome expression was validated in the brain tissue of patients who had SE or drug-resistant TLE and the effect of rapamycin was studied in primary human astrocyte cultures.
RESULTS: In post-SE rats, increased (immuno)proteasome expression was detected throughout epileptogenesis in neurons and astrocytes within the hippocampus and piriform cortex and was most evident in rats that developed a progressive form of epilepsy. Rapamycin-treated post-SE rats had reduced (immuno)proteasome protein expression and a lower number of spontaneous seizures compared to vehicle-treated rats. (Immuno)proteasome expression was also increased in neurons and astrocytes within the human hippocampus after SE and in patients with drug-resistant TLE. In vitro studies using cultured human astrocytes showed that interleukin (IL)-1β-induced (immuno)proteasome gene expression could be attenuated by rapamycin.
SIGNIFICANCE: Because dysregulation of the (immuno)proteasome system is observed before the occurrence of spontaneous seizures in rats, is associated with progression of epilepsy, and can be modulated via the mTOR pathway, it may represent an interesting novel target for drug treatment in epilepsy.
Löscher W, Ferland RJ, Ferraro TN. The relevance of inter- and intrastrain differences in mice and rats and their implications for models of seizures and epilepsy. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28651171) Epilepsy Behav. 2017 Aug;73:214-235
It is becoming increasingly clear that the genetic background of mice and rats, even in inbred strains, can have a profound influence on measures of seizure susceptibility and epilepsy. These differences can be capitalized upon through genetic mapping studies to reveal genes important for seizures and epilepsy. However, strain background and particularly mixed genetic backgrounds of transgenic animals need careful consideration in both the selection of strains and in the interpretation of results and conclusions. For instance, mice with targeted deletions of genes involved in epilepsy can have profoundly disparate phenotypes depending on the background strain. In this review, we discuss findings related to how this genetic heterogeneity has and can be utilized in the epilepsy field to reveal novel insights into seizures and epilepsy. Moreover, we discuss how caution is needed in regards to rodent strain or even animal vendor choice, and how this can significantly influence seizure and epilepsy parameters in unexpected ways. This is particularly critical in decisions regarding the strain of choice used in generating mice with targeted deletions of genes. Finally, we discuss the role of environment (at vendor and/or laboratory) and epigenetic factors for inter- and intrastrain differences and how such differences can affect the expression of seizures and the animals' performance in behavioral tests that often accompany acute and chronic seizure testing.
Löscher W. Animal Models of Seizures and Epilepsy: Past, Present, and Future Role for the Discovery of Antiseizure Drugs. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28290134). Neurochem Res. 2017 Jul;42(7):1873-1888
The identification of potential therapeutic agents for the treatment of epilepsy requires the use of seizure models. Except for some early treatments, including bromides and phenobarbital, the antiseizure activity of all clinically used drugs was, for the most part, defined by acute seizure models in rodents using the maximal electroshock and subcutaneous pentylenetetrazole seizure tests and the electrically kindled rat. Unfortunately, the clinical evidence to date would suggest that none of these models, albeit useful, are likely to identify those therapeutics that will effectively manage patients with drug resistant seizures. Over the last 30 years, a number of animal models have been developed that display varying degrees of pharmacoresistance, such as the phenytoin- or lamotrigine-resistant kindled rat, the 6-Hz mouse model of partial seizures, the intrahippocampal kainate model in mice, or rats in which spontaneous recurrent seizures develops after inducing status epilepticus by chemical or electrical stimulation. As such, these models can be used to study mechanisms of drug resistance and may provide a unique opportunity for identifying a truly novel antiseizure drug (ASD), but thus far clinical evidence for this hope is lacking. Although animal models of drug resistant seizures are now included in ASD discovery approaches such as the ETSP (epilepsy therapy screening program), it is important to note that no single model has been validated for use to identify potential compounds for as yet drug resistant seizures, but rather a battery of such models should be employed, thus enhancing the sensitivity to discover novel, highly effective ASDs. The present review describes the previous and current approaches used in the search for new ASDs and offers some insight into future directions incorporating new and emerging animal models of therapy resistance.
Pauletti A, Terrone G, Shekh-Ahmad T, Salamone A, Ravizza T, Rizzi M, Pastore A, Pascente R, Liang LP, Villa BR, Balosso S, Abramov AY, van Vliet EA, Del Giudice E, Aronica E, Antoine DJ, Patel M, Walker MC, Vezzani A. Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28575153) Brain. 2017 Jul 1;140(7):1885-1899
Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of disulfide high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented disulfide HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.
Löscher W. The Search for New Screening Models of Pharmacoresistant Epilepsy: Is Induction of Acute Seizures in Epileptic Rodents a Suitable Approach?. (https://www.ncbi.nlm.nih.gov/pubmed/?term=27502939) Neurochem Res. 2017 Jul;42(7):1926-1938
Epilepsy, a prevalent neurological disease characterized by spontaneous recurrent seizures (SRS), is often refractory to treatment with anti-seizure drugs (ASDs), so that more effective ASDs are urgently needed. For this purpose, it would be important to develop, validate, and implement new animal models of pharmacoresistant epilepsy into drug discovery. Several chronic animal models with difficult-to-treat SRS do exist; however, most of these models are not suited for drug screening, because drug testing on SRS necessitates laborious video-EEG seizure monitoring. More recently, it was proposed that, instead of monitoring SRS, chemical or electrical induction of acute seizures in epileptic rodents may be used as a surrogate for testing the efficacy of novel ASDs against refractory SRS. Indeed, several ASDs were shown to lose their efficacy on acute seizures, when such seizures were induced by pentylenetetrazole (PTZ) in epileptic rather than nonepileptic rats, whereas this was not observed when using the maximal electroshock seizure test. Subsequent studies confirmed the loss of anti-seizure efficacy of valproate against PTZ-induced seizures in epileptic mice, but several other ASDs were more potent against PTZ in epileptic than nonepileptic mice. This was also observed when using the 6-Hz model of partial seizures in epileptic mice, in which the potency of levetiracetam, in particular, was markedly increased compared to nonepileptic animals. Overall, these observations suggest that performing acute seizure tests in epileptic rodents provides valuable information on the pharmacological profile of ASDs, in particular those with mechanisms inherent to disease-induced brain alterations. However, it appears that further work is needed to define optimal approaches for acute seizure induction and generation of epileptic/drug refractory animals that would permit reliable screening of new ASDs with improved potential to provide seizure control in patients with pharmacoresistant epilepsy.
Bekenstein U, Mishra N, Milikovsky DZ, Hanin G, Zelig D, Sheintuch L, Berson A, Greenberg DS, Friedman A, Soreq H. Dynamic changes in murine forebrain miR-211 expression associate with cholinergic imbalances and epileptiform activity. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28584127) Proc Natl Acad Sci U S A. 2017 Jun 20;114(25):E4996-E5005
Epilepsy is a common neurological disease, manifested in unprovoked recurrent seizures. Epileptogenesis may develop due to genetic or pharmacological origins or following injury, but it remains unclear how the unaffected brain escapes this susceptibility to seizures. Here, we report that dynamic changes in forebrain microRNA (miR)-211 in the mouse brain shift the threshold for spontaneous and pharmacologically induced seizures alongside changes in the cholinergic pathway genes, implicating this miR in the avoidance of seizures. We identified miR-211 as a putative attenuator of cholinergic-mediated seizures by intersecting forebrain miR profiles that were Argonaute precipitated, synaptic vesicle target enriched, or differentially expressed under pilocarpine-induced seizures, and validated TGFBR2 and the nicotinic antiinflammatory acetylcholine receptor nAChRa7 as murine and human miR-211 targets, respectively. To explore the link between miR-211 and epilepsy, we engineered dTg-211 mice with doxycycline-suppressible forebrain overexpression of miR-211. These mice reacted to doxycycline exposure by spontaneous electrocorticography-documented nonconvulsive seizures, accompanied by forebrain accumulation of the convulsive seizures mediating miR-134. RNA sequencing demonstrated in doxycycline-treated dTg-211 cortices overrepresentation of synaptic activity, Ca2+ transmembrane transport, TGFBR2 signaling, and cholinergic synapse pathways. Additionally, a cholinergic dysregulated mouse model overexpressing a miR refractory acetylcholinesterase-R splice variant showed a parallel propensity for convulsions, miR-211 decreases, and miR-134 elevation. Our findings demonstrate that in mice, dynamic miR-211 decreases induce hypersynchronization and nonconvulsive and convulsive seizures, accompanied by expression changes in cholinergic and TGFBR2 pathways as well as in miR-134. Realizing the importance of miR-211 dynamics opens new venues for translational diagnosis of and interference with epilepsy.
Jozwiak S, Becker A, Cepeda C, Engel J, Gnatkovsky V, Huberfeld G, Kaya M, Kobow K, Simonato M, Loeb JA. WONOEP appraisal: Development of epilepsy biomarkers-What we can learn from our patients?. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28387933) Epilepsia. 2017 Jun;58(6):951-961
OBJECTIVE: Current medications for patients with epilepsy work in only two of three patients. For those medications that do work, they only suppress seizures. They treat the symptoms, but do not modify the underlying disease, forcing patients to take these drugs with significant side effects, often for the rest of their lives. A major limitation in our ability to advance new therapeutics that permanently prevent, reduce the frequency of, or cure epilepsy comes from a lack of understanding of the disease coupled with a lack of reliable biomarkers that can predict who has or who will get epilepsy.
METHODS: The main goal of this report is to present a number of approaches for identifying reliable biomarkers from observing patients with brain disorders that have a high probability of producing epilepsy.
RESULTS: A given biomarker, or more likely a profile of biomarkers, will have both a quantity and a time course during epileptogenesis that can be used to predict who will get the disease, to confirm epilepsy as a diagnosis, to identify coexisting pathologies, and to monitor the course of treatments.
SIGNIFICANCE: Additional studies in patients and animal models could identify common and clinically valuable biomarkers to successfully translate animal studies into new and effective clinical trials.
Bar-Klein G, Lublinsky S, Kamintsky L, Noyman I, Veksler R, Dalipaj H, Senatorov VV, Swissa E, Rosenbach D, Elazary N, Milikovsky DZ, Milk N, Kassirer M, Rosman Y, Serlin Y, Eisenkraft A, Chassidim Y, Parmet Y, Kaufer D, Friedman A. Imaging blood–brain barrier dysfunction as a biomarker for epileptogenesis. (https://www.ncbi.nlm.nih.gov/pubmed/28444141) Brain. 2017 Jun 1;140(6):1692-1705
A biomarker that will enable the identification of patients at high-risk for developing post-injury epilepsy is critically required. Microvascular pathology and related blood-brain barrier dysfunction and neuroinflammation were shown to be associated with epileptogenesis after injury. Here we used prospective, longitudinal magnetic resonance imaging to quantitatively follow blood-brain barrier pathology in rats following status epilepticus, late electrocorticography to identify epileptic animals and post-mortem immunohistochemistry to confirm blood-brain barrier dysfunction and neuroinflammation. Finally, to test the pharmacodynamic relevance of the proposed biomarker, two anti-epileptogenic interventions were used; isoflurane anaesthesia and losartan. Our results show that early blood-brain barrier pathology in the piriform network is a sensitive and specific predictor (area under the curve of 0.96, P < 0.0001) for epilepsy, while diffused pathology is associated with a lower risk. Early treatments with either isoflurane anaesthesia or losartan prevented early microvascular damage and late epilepsy. We suggest quantitative assessment of blood-brain barrier pathology as a clinically relevant predictive, diagnostic and pharmaco!dynamics biomarker for acquired epilepsy.
Twele F, Schidlitzki A, Töllner K, Löscher W. The intrahippocampal kainate mouse model of mesial temporal lobe epilepsy: Lack of electrographic seizure-like events in sham controls. (http://onlinelibrary.wiley.com/doi/10.1002/epi4.12044/full) Epilepsia Open, 2: 180–187, 2017 June
Objective: There is an ongoing debate about definition of seizures in experimental models of acquired epilepsy and how important adequate sham controls are in this respect. For instance, several mouse and rat strains exhibit high-voltage rhythmic spike or spike-wave discharges in the cortical electroencephalogram (EEG), which has to be considered when using such strains for induction of epilepsy by status epilepticus, traumatic brain injury, or other means. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of kainate are increasingly being used as a model of mesial temporal lobe epilepsy. We performed a prospective study in which EEG alterations occurring in this model were compared with the EEGs in appropriate sham controls, using hippocampal electrodes and video-EEG monitoring.
Methods: Experiments with intrahippocampal kainate (or saline) injections started when mice were about 8 weeks of age. Continuous video-EEG recording via hippocampal electrodes was performed 6 weeks after surgery in kainate-injected mice and sham controls, that is, at an age of about 14 weeks. Three days of continuous video-EEG monitoring were compared between kainate-injected mice and experimental controls.
Results: As reported previously, kainate-injected mice exhibited two types of highly frequent electrographic seizures: high-voltage sharp waves, which were often monomorphic, and polymorphic hippocampal paroxysmal discharges. In addition, generalized convulsive clinical seizures were infrequently observed. None of these electrographic or electroclinical seizures were observed in sham controls. The only infrequently observed EEG abnormalities in sham controls were isolated spikes or spike clusters, which were also recorded in epileptic mice.
Significance: This study rigorously demonstrates, by explicit comparison with the EEGs of sham controls, that the nonconvulsive paroxysmal events observed in this model are consequences of the induced epilepsy and not features of the EEG expected to be seen in some experimental control mice or unintentionally induced by surgical procedures.
Milikovsky DZ, Weissberg I, Kamintsky L, Lippmann K, Schefenbauer O, Frigerio F, Rizzi M, Sheintuch L, Zelig D, Ofer J, Vezzani A, Friedman A. Electrocorticographic Dynamics as a Novel Biomarker in Five Models of Epileptogenesis. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28330876) J Neurosci. 2017 Apr 26;37(17):4450-4461
Postinjury epilepsy (PIE) is a devastating sequela of various brain insults. While recent studies offer novel insights into the mechanisms underlying epileptogenesis and discover potential preventive treatments, the lack of PIE biomarkers hinders the clinical implementation of such treatments. Here we explored the biomarker potential of different electrographic features in five models of PIE. Electrocorticographic or intrahippocampal recordings of epileptogenesis (from the insult to the first spontaneous seizure) from two laboratories were analyzed in three mouse and two rat PIE models. Time, frequency, and fractal and nonlinear properties of the signals were examined, in addition to the daily rate of epileptiform spikes, the relative power of five frequency bands (theta, alpha, beta, low gamma, and high gamma) and the dynamics of these features over time. During the latent pre-seizure period, epileptiform spikes were more frequent in epileptic compared with nonepileptic rodents; however, this feature showed limited predictive power due to high inter- and intra-animal variability. While nondynamic rhythmic representation failed to predict epilepsy, the dynamics of the theta band were found to predict PIE with a sensitivity and specificity of >90%. Moreover, theta dynamics were found to be inversely correlated with the latency period (and thus predict the onset of seizures) and with the power change of the high-gamma rhythm. In addition, changes in theta band power during epileptogenesis were associated with altered locomotor activity and distorted circadian rhythm. These results suggest that changes in theta band during the epileptogenic period may serve as a diagnostic biomarker for epileptogenesis, able to predict the future onset of spontaneous seizures.SIGNIFICANCE STATEMENT Postinjury epilepsy is an unpreventable and devastating disorder that develops following brain injuries, such as traumatic brain injury and stroke, and is often associated with neuropsychiatric comorbidities. As PIE affects as many as 20% of brain-injured patients, reliable biomarkers are imperative before any preclinical therapeutics can find clinical translation. We demonstrate the capacity to predict the epileptic outcome in five different models of PIE, highlighting theta rhythm dynamics as a promising biomarker for epilepsy. Our findings prompt the exploration of theta dynamics (using repeated electroencephalographic recordings) as an epilepsy biomarker in brain injury patients.
Prada Jardim A, Liu J, Baber J, Michalak Z, Reeves C, Ellis M, Novy J, de Tisi J, McEvoy A, Miserocchi A, Targas Yacubian EM, Sisodiya S, Thompson P, Thom M. Characterising subtypes of hippocampal sclerosis and reorganization: correlation with pre and postoperative memory deficit. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28380661) Brain Pathol. 2017 Apr 5
Neuropathological subtypes of hippocampal sclerosis (HS) in temporal lobe epilepsy (The 2013 International League Against Epilepsy classification) are based on the qualitative assessment of patterns of neuronal loss with NeuN. In practice, some cases appear indeterminate between type 1 (CA1 and CA4 loss) and type 2 HS (CA1 loss) and we predicted that MAP2 would enable a more stringent classification. HS subtypes, as well as the accompanying alteration of axonal networks, regenerative capacity and neurodegeneration have been previously correlated with outcome and memory deficits and may provide prognostic clinical information. We selected 92 cases: 52 type 1 HS, 15 type 2 HS, 18 indeterminate-HS and 7 no-HS. Quantitative analysis was carried out on NeuN and MAP2 stained sections and a labeling index (LI) calculated for six hippocampal subfields. We also evaluated hippocampal regenerative activity (MCM2, nestin, olig2, calbindin), degeneration (AT8/phosphorylated tau) and mossy-fiber pathway re-organization (ZnT3). Pathology measures were correlated with clinical epilepsy history, memory and naming test scores and postoperative outcomes, at 1 year following surgery. MAP2 LI in indeterminate-HS was statistically similar to type 2 HS but this clustering was not shown with NeuN. Moderate verbal and visual memory deficits were noted in all HS types, including 54% and 69% of type 2 HS. Memory deficits correlated with several pathology factors including lower NeuN or MAP2 LI in CA4, CA1, dentate gyrus (DG) and subiculum and poor preservation of the mossy fiber pathway. Decline in memory at 1 year associated with AT8 labeling in the subiculum and DG but not HS type. We conclude that MAP2 is a helpful addition in the classification of HS in some cases. Classification of HS subtype, however, did not significantly correlate with outcome or pre- or postoperative memory dysfunction, which was associated with multiple pathology factors including hippocampal axonal pathways, regenerative capacity and degenerative changes.
Puhakka N, Bot AM, Vuokila N, Debski KJ, Lukasiuk K, Pitkänen A. Chronically dysregulated NOTCH1 interactome in the dentate gyrus after traumatic brain injury. (https://www.ncbi.nlm.nih.gov/pubmed/?term=28273100) PLoS One. 2017 Mar 8;12(3):e0172521
Traumatic brain injury (TBI) can result in several dentate gyrus-regulated disabilities. Almost nothing is known about the chronic molecular changes after TBI, and their potential as treatment targets. We hypothesized that chronic transcriptional alterations after TBI are under microRNA (miRNA) control. Expression of miRNAs and their targets in the dentate gyrus was analyzed using microarrays at 3 months after experimental TBI. Of 305 miRNAs present on the miRNA-array, 12 were downregulated (p<0.05). In parallel, 75 of their target genes were upregulated (p<0.05). A bioinformatics analysis of miRNA targets highlighted the dysregulation of the transcription factor NOTCH1 and 39 of its target genes (NOTCH1 interactome). Validation assays confirmed downregulation of miR-139-5p, upregulation of Notch1 and its activated protein, and positive enrichment of NOTCH1 target gene expression. These findings demonstrate that miRNA-based transcriptional regulation can be present at chronic time points after TBI, and highlight the NOTCH1 interactome as one of the mechanisms behind the dentate gyrus pathology-related morbidities.
to the top
EPITARGET presentations - a selection
J.A. Gorter (AMC). Rapamycin effects on BBB leakage, inflammation, epileptogenesis and seizures. Immunity and Inflammation Meeting 2016, Milan, Italy, October 14, 2016.
E. Aronica (AMC). Epigenetic control of neuroinflammation: miRNAs and epileptogenesis. Immunity and Inflammation Meeting 2016, Milan, Italy, October 14, 2016.
E. Aronica (AMC). New challenges in FCD: molecular mechanisms of epileptogenesis. 12th European Congress on Epileptology, Prague, Czech Republic, September 14, 2016.
E.A. van Vliet (AMC). mTOR inhibition to restore blood-brain barrier leakage in epilepsy. 12th European Congress on Epileptology, Prague, Czech Republic, September 15, 2016.
A. Vezzani (IRFMN). microRNA and inflammation: new therapeutic opportunities in epilepsy associated pathologies. 31st European Epilepsy Congress (ECE), 11-15 September 2016, Prague, Czech Republic.
A. Vezzani (IRFMN). Disulfide HMGB1 is generated by oxidative stress in the rat hippocampus during epileptogenesis and represents a novel mechanism of disease onset an progression. 31st European Epilepsy Congress (ECE), 11-15 September 2016, Prague, Czech Republic.
R. Ravizza (IRFMN). In vivo biomarkers of neuroinflammation: can they track disease progression?. 31st European Epilepsy Congress (ECE), 11-15 September 2016, Prague, Czech Republic.
T. Ravizza (IRFMN). Targeting IL-1beta and HMGB1 with drug combinations. 70th American Epilepsy Society annual meeting, 2-6 December 2016, Houston, Texas, USA.
M. Simonato (UNIFER). miRNAs in comorbid epilepsy and depression. Conference "Novel treatment and re-habilitation strategies for neurological disorders and their comorbidities", June 11, 2016, Tbilisi, Georgia.
Presentations at the 2nd EPITARGET Young Researchers’ Symposium in Marseille- the list of presentations including the abstracts can be found in the abstract booklet.
to the top
EPITARGET presentations - a selection
Simonato M. Neurotrophic factors and status epilepticus. 6th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures, Salzburg, Austria, April 6, 2017.
Bankstahl J. Multimodal evaluation of neuroinflammation-associated changes during epileptogenesis using small animal PET and MRI. Society for Nuclear Medicine and Molecular Imaging Meeting 2017, Denver, USA, June 6, 2017
Jahreis I. Characterization of a modified lithium-pilocarpine model with effective termination of status epilepticus using in vivo imaging and behavioral test. Vetpharm 2017, Leipzig, Germany, September 29, 2017.
Aronica E. MicroRNA-induced silencing in epilepsy – potential treatment target and biomarker. American Epilepsy Society Annual Meeting, Washington, USA, December 2, 2017.
Presentations at the 3rd EPITARGET Young Researchers’ Symposium in Warsaw - the list of presentations including the abstracts can be found in the abstract booklet.
to the top
EPITARGET posters - a selection
Nizinska K, Szydlowska K, Lukasiuk K. 13th International Congress Polish Neuroscience Society, Warsaw, Poland, August 28-31, 2017.
- Behavioral characteristic as a biomarker of development and phenotype of epilepsy in the temporal lobe epilepsy induced by electrical stimulation of the amygdala in rats.
- Circulating microRNA as a biomarker of epileptogenesis and epilepsy in the rat model of temporal lobe epilepsy.
- The impact of environment enrichment on anxiety and learning in the rat model of epilepsy induced by electrical stimulation of the amygdala.
Bankstahl JP. Multi-tracer characterization of an animal model of epileptogenesis by serial molecular in vivo imaging. Brain&BrainPET 2017, Berlin, Germany, April 01-04, 2017.
Kubajewska I. Nano-enabled Brain Delivery Of Therapeutic Proteins For The Treatment Of Neurodegenerative Diseases. AAPS Annual Meeting and Exposition, San Diego, USA, November 15, 2017.
Poster presentations at the 3rd EPITARGET Young Researchers’ Symposium in Warsaw - the list of posters including the abstracts can be found in the abstract booklet.
to the top