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Monni L, Kraus L, Dipper-Wawra M, Soares-da-Silva P, Maier N, Schmitz D, Holtkamp M, Fidzinski P. In vitro and in vivo anti-epileptic efficacy of eslicarbazepine acetate in a mouse model of KCNQ2-related self-limited epilepsy. Br J Pharmacol 2021; 179:84-102. [PMID: 34605012 DOI: 10.1111/bph.15689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 08/26/2021] [Accepted: 09/08/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The KCNQ2 gene encodes for the Kv 7.2 subunit of non-inactivating potassium channels. KCNQ2-related diseases range from autosomal dominant neonatal self-limited epilepsy, often caused by KCNQ2 haploinsufficiency, to severe encephalopathies caused by KCNQ2 missense variants. In vivo and in vitro effects of the sodium channel blocker eslicarbazepine acetate (ESL) and eslicarbazepine metabolite (S-Lic) in a mouse model of self-limited neonatal epilepsy as a first attempt to assess the utility of ESL in the KCNQ2 disease spectrum was investigated. EXPERIMENTAL APPROACH Effects of S-Lic on in vitro physiological and pathological hippocampal neuronal activity in slices from mice carrying a heterozygous deletion of Kcnq2 (Kcnq2+/- ) and Kcnq2+/+ mice were investigated. ESL in vivo efficacy was investigated in the 6-Hz psychomotor seizure model in both Kcnq2+/- and Kcnq2+/+ mice. KEY RESULTS S-Lic increased the amplitude and decreased the incidence of physiological sharp wave-ripples in a concentration-dependent manner and slightly decreased gamma oscillations frequency. 4-Aminopyridine-evoked seizure-like events were blocked at high S-Lic concentrations and substantially reduced in incidence at lower concentrations. These results were not different in Kcnq2+/+ and Kcnq2+/- mice, although the EC50 estimation implicated higher efficacy in Kcnq2+/- animals. In vivo, Kcnq2+/- mice had a lower seizure threshold than Kcnq2+/+ mice. In both genotypes, ESL dose-dependently displayed protection against seizures. CONCLUSIONS AND IMPLICATIONS S-Lic slightly modulates hippocampal oscillations and blocks epileptic activity in vitro and in vivo. Our results suggest that the increased excitability in Kcnq2+/- mice is effectively targeted by S-Lic high concentrations, presumably by blocking diverse sodium channel subtypes.
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Affiliation(s)
- Laura Monni
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Clinical Research Centre, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Larissa Kraus
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Life Sciences Institute, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthias Dipper-Wawra
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Patricio Soares-da-Silva
- Division of Research and Development, BIAL - Portela & CA S. A, da Siderurgia Nacional, São Mamede do Coronado, Portugal.,Department of Biomedicine, Unit of Pharmacology and Therapeutics, Faculty of Medicine, University Porto, Porto, Portugal.,MedInUP, Centre for Drug Discovery and Innovative Medicines, University Porto, Porto, Portugal
| | - Nikolaus Maier
- Neuroscience Research Centre, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Centre, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Martin Holtkamp
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Pawel Fidzinski
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Clinical Research Centre, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
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Schlabitz S, Monni L, Ragot A, Dipper-Wawra M, Onken J, Holtkamp M, Fidzinski P. Spatiotemporal Correlation of Epileptiform Activity and Gene Expression in vitro. Front Mol Neurosci 2021; 14:643763. [PMID: 33859552 PMCID: PMC8042243 DOI: 10.3389/fnmol.2021.643763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/03/2021] [Indexed: 11/14/2022] Open
Abstract
Epileptiform activity alters gene expression in the central nervous system, a phenomenon that has been studied extensively in animal models. Here, we asked whether also in vitro models of seizures are in principle suitable to investigate changes in gene expression due to epileptiform activity and tested this hypothesis mainly in rodent and additionally in some human brain slices. We focused on three genes relevant for seizures and epilepsy: FOS proto-oncogene (c-Fos), inducible cAMP early repressor (Icer) and mammalian target of rapamycin (mTor). Seizure-like events (SLEs) were induced by 4-aminopyridine (4-AP) in rat entorhinal-hippocampal slices and by 4-AP/8 mM potassium in human temporal lobe slices obtained from surgical treatment of epilepsy. SLEs were monitored simultaneously by extracellular field potentials and intrinsic optical signals (IOS) for 1–4 h, mRNA expression was quantified by real time PCR. In rat slices, both duration of SLE exposure and SLE onset region were associated with increased expression of c-Fos and Icer while no such association was shown for mTor expression. Similar to rat slices, c-FOS induction in human tissue was increased in slices with epileptiform activity. Our results indicate that irrespective of limitations imposed by ex vivo conditions, in vitro models represent a suitable tool to investigate gene expression. Our finding is of relevance for the investigation of human tissue that can only be performed ex vivo. Specifically, it presents an important prerequisite for future studies on transcriptome-wide and cell-specific changes in human tissue with the goal to reveal novel candidates involved in the pathophysiology of epilepsy and possibly other CNS pathologies.
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Affiliation(s)
- Sophie Schlabitz
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Laura Monni
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Alienor Ragot
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Matthias Dipper-Wawra
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Julia Onken
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurosurgery, Berlin, Germany
| | - Martin Holtkamp
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Pawel Fidzinski
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany.,Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, Neuroscience Research Center, Berlin, Germany
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Kraus L, Monni L, Schneider UC, Onken J, Spindler P, Holtkamp M, Fidzinski P. Preparation of Acute Human Hippocampal Slices for Electrophysiological Recordings. J Vis Exp 2020. [PMID: 32449727 DOI: 10.3791/61085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Epilepsy affects about 1% of the world population and leads to a severe decrease in quality of life due to ongoing seizures as well as high risk for sudden death. Despite an abundance of available treatment options, about 30% of patients are drug-resistant. Several novel therapeutics have been developed using animal models, though the rate of drug-resistant patients remains unaltered. One of probable reasons is the lack of translation between rodent models and humans, such as a weak representation of human pharmacoresistance in animal models. Resected human brain tissue as a preclinical evaluation tool has the advantage to bridge this translational gap. Described here is a method for high quality preparation of human hippocampal brain slices and subsequent stable induction of epileptiform activity. The protocol describes the induction of burst activity during application of 8 mM KCl and 4-aminopyridin. This activity is sensitive to established AED lacosamide or novel antiepileptic candidates, such as dimethylethanolamine (DMEA). In addition, the method describes induction of seizure-like events in CA1 of human hippocampal brain slices by reduction of extracellular Mg2+ and application of bicuculline, a GABAA receptor blocker. The experimental set-up can be used to screen potential antiepileptic substances for their effects on epileptiform activity. Furthermore, mechanisms of action postulated for specific compounds can be validated using this approach in human tissue (e.g., using patch-clamp recordings). To conclude, investigation of vital human brain tissue ex vivo (here, resected hippocampus from patients suffering from temporal lobe epilepsy) will improve the current knowledge of physiological and pathological mechanisms in the human brain.
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Affiliation(s)
- Larissa Kraus
- Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Laura Monni
- Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Ulf C Schneider
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Julia Onken
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Philipp Spindler
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Martin Holtkamp
- Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health
| | - Pawel Fidzinski
- Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health;
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Ghezzi F, Monni L, Nistri A. Functional up-regulation of the M-current by retigabine contrasts hyperexcitability and excitotoxicity on rat hypoglossal motoneurons. J Physiol 2018; 596:2611-2629. [PMID: 29736957 DOI: 10.1113/jp275906] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Excessive neuronal excitability characterizes several neuropathological conditions, including neurodegenerative diseases such as amyotrophic lateral sclerosis. Hypoglossal motoneurons (HMs), which control tongue muscles, are extremely vulnerable to this disease and undergo damage and death when exposed to an excessive glutamate extracellular concentration that causes excitotoxicity. Our laboratory devised an in vitro model of excitotoxicity obtained by pharmacological blockade of glutamate transporters. In this paradigm, HMs display hyperexcitability, collective bursting and eventually cell death. The results of the present study show that pharmacological up-regulation of a K+ current (M-current), via application of the anti-convulsant retigabine, prevented all hallmarks of HM excitotoxicity, comprising bursting, generation of reactive oxygen species, expression of toxic markers and cell death. ○Our data may have translational value to develop new treatments against neurological diseases by using positive pharmacological modulators of the M-current. ABSTRACT Neuronal hyperexcitability is a symptom characterizing several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). In the ALS bulbar form, hypoglossal motoneurons (HMs) are an early target for neurodegeneration because of their high vulnerability to metabolic insults. In recent years, our laboratory has developed an in vitro model of a brainstem slice comprising the hypoglossal nucleus in which HM neurodegeneration is achieved by blocking glutamate clearance with dl-threo-β-benzyloxyaspartate (TBOA), thus leading to delayed excitotoxicity. During this process, HMs display a set of hallmarks such as hyperexcitability (and network bursting), reactive oxygen species (ROS) generation and, finally, cell death. The present study aimed to investigate whether blocking early hyperexcitability and bursting with the anti-convulsant drug retigabine was sufficient to achieve neuroprotection against excitotoxicity. Retigabine is a selective positive allosteric modulator of the M-current (IM ), an endogenous mechanism that neurons (comprising HMs) express to dampen excitability. Retigabine (10 μm; co-applied with TBOA) contrasted ROS generation, release of endogenous toxic factors into the HM cytoplasm and excitotoxicity-induced HM death. Electrophysiological experiments showed that retigabine readily contrasted and arrested bursting evoked by TBOA administration. Because neuronal IM subunits (Kv7.2, Kv7.3 and Kv7.5) were expressed in the hypoglossal nucleus and in functionally connected medullary nuclei, we suggest that they were responsible for the strong reduction in network excitability, a potent phenomenon for achieving neuroprotection against TBOA-induced excitotoxicity. The results of the present study may have translational value for testing novel positive pharmacological modulators of the IM under pathological conditions (including neurodegenerative disorders) characterized by excessive neuronal excitability.
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Affiliation(s)
- Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
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Ghezzi F, Monni L, Corsini S, Rauti R, Nistri A. Propofol Protects Rat Hypoglossal Motoneurons in an In Vitro Model of Excitotoxicity by Boosting GABAergic Inhibition and Reducing Oxidative Stress. Neuroscience 2017; 367:15-33. [PMID: 29069620 DOI: 10.1016/j.neuroscience.2017.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/10/2017] [Accepted: 10/16/2017] [Indexed: 12/14/2022]
Abstract
In brainstem motor networks, hypoglossal motoneurons (HMs) play the physiological role of driving tongue contraction, an activity critical for inspiration, phonation, chewing and swallowing. HMs are an early target of neurodegenerative diseases like amyotrophic lateral sclerosis that, in its bulbar form, is manifested with initial dysphagia and dysarthria. One important pathogenetic component of this disease is the high level of extracellular glutamate due to uptake block that generates excitotoxicity. To understand the earliest phases of this condition we devised a model, the rat brainstem slice, in which block of glutamate uptake is associated with intense bursting of HMs, dysmetabolism and death. Since blocking bursting becomes a goal to prevent cell damage, the present report enquired whether boosting GABAergic inhibition could fulfill this aim and confer beneficial outcome. Propofol (0.5 µM) and midazolam (0.01 µM), two allosteric modulators of GABAA receptors, were used at concentrations yielding analogous potentiation of GABA-mediated currents. Propofol also partly depressed NMDA receptor currents. Both drugs significantly shortened bursting episodes without changing single burst properties, their synchronicity, or their occurrence. Two hours later, propofol prevented the rise in reactive oxygen species (ROS) and, at 4 hours, it inhibited intracellular release of apoptosis-inducing factor (AIF) and prevented concomitant cell loss. Midazolam did not contrast ROS and AIF release. The present work provides experimental evidence for the neuroprotective action of a general anesthetic like propofol, which, in this case, may be achieved through a combination of boosted GABAergic inhibition and reduced ROS production.
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Affiliation(s)
- Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Silvia Corsini
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Rossana Rauti
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
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Monni L, Ghezzi F, Corsini S, Nistri A. Neurotoxicity of propofol on rat hypoglossal motoneurons in vitro. Neurosci Lett 2017; 655:95-100. [PMID: 28676256 DOI: 10.1016/j.neulet.2017.06.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/15/2017] [Accepted: 06/22/2017] [Indexed: 01/26/2023]
Abstract
Although propofol is a widely used intravenous general anaesthetic, many studies report its toxic potential, particularly on the developing central nervous system. We investigated its action on hypoglossal motoneurons (HMs) that control two critical functions in neonates, namely tongue muscle activity and airway patency. Thus, clinically relevant concentrations of propofol (1 and 5μM) were applied (4h) to neonatal rat brainstem slices to evaluate the expression of apoptosis-inducing factor (AIF) as biomarker of toxicity. This anaesthetic strongly increased AIF in the cytoplasm and the nucleus, without early loss of HMs. Electrophysiological recordings from HMs showed that propofol (5μM) enhanced GABA- and glycine-evoked current amplitude and lengthened GABAergic current decay time. Propofol also depressed NMDA receptor-mediated responses without affecting AMPA receptors. Since GABA and glycine depolarize neonatal HMs, we propose that the damaging action by propofol on these motoneurons might arise from the facilitated action of these transmitters with subsequent cytoplasmic Ca2+ overload. This phenomenon, in turn, may trigger cell death mechanisms manifested as increased expression of AIF and its translocation into the nucleus. Since propofol is also employed for induction and maintenance of paediatric surgery, caution is needed because its potential neurotoxicity might negatively impact neurodevelopment.
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Affiliation(s)
- Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Silvia Corsini
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
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