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Wang F, Wang Y, Zhang QY, Hu KY, Song YJ, Yang L, Fei F, Xu CL, Cui SL, Ruan YP, Wang Y, Chen Z. Small-molecule caspase-1 inhibitor CZL80 terminates refractory status epilepticus via inhibition of glutamatergic transmission. Acta Pharmacol Sin 2024; 45:1381-1392. [PMID: 38514863 PMCID: PMC11192899 DOI: 10.1038/s41401-024-01257-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
Status epilepticus (SE), a serious and often life-threatening medical emergency, is characterized by abnormally prolonged seizures. It is not effectively managed by present first-line anti-seizure medications and could readily develop into drug resistance without timely treatment. In this study, we highlight the therapeutic potential of CZL80, a small molecule that inhibits caspase-1, in SE termination and its related mechanisms. We found that delayed treatment of diazepam (0.5 h) easily induces resistance in kainic acid (KA)-induced SE. CZL80 dose-dependently terminated diazepam-resistant SE, extending the therapeutic time window to 3 h following SE, and also protected against neuronal damage. Interestingly, the effect of CZL80 on SE termination was model-dependent, as evidenced by ineffectiveness in the pilocarpine-induced SE. Further, we found that CZL80 did not terminate KA-induced SE in Caspase-1-/- mice but partially terminated SE in IL1R1-/- mice, suggesting the SE termination effect of CZL80 was dependent on the caspase-1, but not entirely through the downstream IL-1β pathway. Furthermore, in vivo calcium fiber photometry revealed that CZL80 completely reversed the neuroinflammation-augmented glutamatergic transmission in SE. Together, our results demonstrate that caspase-1 inhibitor CZL80 terminates diazepam-resistant SE by blocking glutamatergic transmission. This may be of great therapeutic significance for the clinical treatment of refractory SE.
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Affiliation(s)
- Fei Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Yu Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Qing-Yang Zhang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Ke-Yu Hu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Ying-Jie Song
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Lin Yang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Fan Fei
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Ceng-Lin Xu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Sun-Liang Cui
- Key Laboratory of Medical Neurobiology of The Ministry of Health of China, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Ye-Ping Ruan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
- Key Laboratory of Medical Neurobiology of The Ministry of Health of China, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, 310058, China.
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
- Key Laboratory of Medical Neurobiology of The Ministry of Health of China, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, 310058, China.
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Magro G, Laterza V. Status epilepticus: Is there a Stage 1 plus? Epilepsia 2024; 65:1560-1567. [PMID: 38507275 DOI: 10.1111/epi.17953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/02/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024]
Abstract
In status epilepticus (SE), "time is brain." Currently, first-line therapy consists of benzodiazepines (BDZs) and SE is classified by the response to treatment; stage 2 or established SE is defined as "BDZ-resistant SE." Nonetheless, this classification does not always work, especially in the case of prolonged convulsive SE, where many molecular changes occur and γ-aminobutyric acid signaling becomes excitatory. Under these circumstances, BDZ therapy might not be optimal, and might be possibly detrimental, if given alone; as the duration of SE increases, so too does BDZ resistance. Murine models of SE showed how these cases might benefit more from synergistic combined therapy from the start. The definition of Stage 1 plus is suggested, as a stage requiring combined therapy from the start, which includes prolonged SE with seizure activity going on for >10 min, the time that marks the disruption of receptor homeostasis, with increased internalization. This specific stage might require a synergistic approach from the start, with a combination of first- and second-line treatment.
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Affiliation(s)
- Giuseppe Magro
- Department of Medical and Surgical Sciences, Institute of Neurology, Magna Græcia University, Catanzaro, Italy
| | - Vincenzo Laterza
- Department of Medical and Surgical Sciences, Institute of Neurology, Magna Græcia University, Catanzaro, Italy
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Forsyth R, Allen M, Bedson E, Downes A, Gough C, Hartshorn S, Lawton K, Lyttle MD, Messahel S, Mullen N, Raper J, Rosala-Harris A, Taggart L, Urron J, Walton E, Gamble C. Seizure control via pH manipulation: a phase II double-blind randomised controlled trial of inhaled carbogen as adjunctive treatment of paediatric convulsive status epilepticus (Carbogen for Status Epilepticus in Children Trial (CRESCENT)). Trials 2024; 25:349. [PMID: 38812049 PMCID: PMC11135009 DOI: 10.1186/s13063-024-08188-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/17/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND Paediatric convulsive status epilepticus is the most common neurological emergency presenting to emergency departments. Risks of resultant neurological morbidity and mortality increase with seizure duration. If the seizure fails to stop within defined time-windows, standard care follows an algorithm of stepwise escalation to more intensive treatments, ultimately resorting to induction of general anaesthesia and ventilation. Additionally, ventilatory support may also be required to treat respiratory depression, a common unwanted effect of treatment. There is strong pre-clinical evidence that pH (acid-base balance) is an important determinant of seizure commencement and cessation, with seizures tending to start under alkaline conditions and terminate under acidic conditions. These mechanisms may be particularly important in febrile status epilepticus: prolonged fever-related seizures which predominantly affect very young children. This trial will assess whether imposition of mild respiratory acidosis by manipulation of inhaled medical gas improves response rates to first-line medical treatment. METHODS A double-blind, placebo-controlled trial of pH manipulation as an adjunct to standard medical treatment of convulsive status epilepticus in children. The control arm receives standard medical management whilst inhaling 100% oxygen; the active arm receives standard medical management whilst inhaling a commercially available mixture of 95% oxygen, 5% carbon dioxide known as 'carbogen'. Due to the urgent need to treat the seizure, deferred consent is used. The primary outcome is success of first-line treatment in seizure cessation. Planned subgroup analyses will be undertaken for febrile and non-febrile seizures. Secondary outcomes include rates of induction of general anaesthesia, admission to intensive care, adverse events, and 30-day mortality. DISCUSSION If safe and effective 95% oxygen, 5% carbon dioxide may be an important adjunct in the management of convulsive status epilepticus with potential for pre-hospital use by paramedics, families, and school staff. TRIAL REGISTRATION EudraCT: 2021-005367-49. CTA: 17136/0300/001. ISRCTN 52731862. Registered on July 2022.
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Affiliation(s)
- Rob Forsyth
- Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK.
- Newcastle University, Newcastle Upon Tyne, UK.
| | - Maria Allen
- Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Emma Bedson
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, UK
| | | | - Chris Gough
- Nottingham University Hospitals NHS Trust, Nottingham, UK
| | | | | | - Mark D Lyttle
- Emergency Department, Bristol Royal Hospital for Children, Bristol, UK
- Research in Emergency Care Avon Collaborative Hub (REACH), University of the West of England, Bristol, UK
| | | | - Niall Mullen
- Sunderland and South Tyneside NHS Foundation Trust, Sunderland, UK
| | - Joseph Raper
- Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Anna Rosala-Harris
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, UK
| | - Leigh Taggart
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, UK
| | - Jason Urron
- Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Emily Walton
- University Hospitals Sussex NHS Foundation Trust, Worthing, UK
| | - Carrol Gamble
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, UK
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Wendling F, Koksal-Ersoz E, Al-Harrach M, Yochum M, Merlet I, Ruffini G, Bartolomei F, Benquet P. Multiscale neuro-inspired models for interpretation of EEG signals in patients with epilepsy. Clin Neurophysiol 2024; 161:198-210. [PMID: 38520800 DOI: 10.1016/j.clinph.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 03/06/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
OBJECTIVE The aim is to gain insight into the pathophysiological mechanisms underlying interictal epileptiform discharges observed in electroencephalographic (EEG) and stereo-EEG (SEEG, depth electrodes) recordings performed during pre-surgical evaluation of patients with drug-resistant epilepsy. METHODS We developed novel neuro-inspired computational models of the human cerebral cortex at three different levels of description: i) microscale (detailed neuron models), ii) mesoscale (neuronal mass models) and iii) macroscale (whole brain models). Although conceptually different, micro- and mesoscale models share some similar features, such as the typology of neurons (pyramidal cells and three types of interneurons), their spatial arrangement in cortical layers, and their synaptic connectivity (excitatory and inhibitory). The whole brain model consists of a large-scale network of interconnected neuronal masses, with connectivity based on the human connectome. RESULTS For these three levels of description, the fine-tuning of free parameters and the quantitative comparison with real data allowed us to reproduce interictal epileptiform discharges with a high degree of fidelity and to formulate hypotheses about the cell- and network-related mechanisms underlying the generation of fast ripples and SEEG-recorded epileptic spikes and spike-waves. CONCLUSIONS The proposed models provide valuable insights into the pathophysiological mechanisms underlying the generation of epileptic events. The knowledge gained from these models effectively complements the clinical analysis of SEEG data collected during the evaluation of patients with epilepsy. SIGNIFICANCE These models are likely to play a key role in the mechanistic interpretation of epileptiform activity.
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Affiliation(s)
| | | | | | | | | | | | - Fabrice Bartolomei
- APHM, Timone Hospital, Epileptology and Cerebral Rhythmology Department, Marseille, France; Univ Aix Marseille, INSERM, INS, Inst Neurosci Syst, Marseille, France
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5
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Daoud M, Durelle C, Fierain A, N EY, Wendling F, Ruffini G, Benquet P, Bartolomei F. Long-term Effect of Multichannel tDCS Protocol in Patients with Central Cortex Epilepsies Associated with Epilepsia Partialis Continua. Brain Topogr 2024:10.1007/s10548-024-01045-3. [PMID: 38446345 DOI: 10.1007/s10548-024-01045-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
Epilepsia partialis continua (EPC) is a rare type of focal motor status epilepticus that causes continuous muscle jerking in a specific part of the body. Experiencing this type of seizure, along with other seizure types, such as focal motor seizures and focal to bilateral tonic-clonic seizures, can result in a disabling situation. Non-invasive brain stimulation methods like transcranial direct current stimulation (tDCS) show promise in reducing seizure frequency (SF) when medications are ineffective. However, research on tDCS for EPC and related seizures is limited. We evaluated personalized multichannel tDCS in drug-resistant EPC of diverse etiologies for long-term clinical efficacy We report three EPC patients undergoing a long-term protocol of multichannel tDCS. The patients received several cycles (11, 9, and 3) of five consecutive days of stimulation at 2 mA for 2 × 20 min, targeting the epileptogenic zone (EZ), including the central motor cortex with cathodal electrodes. The primary measurement was SF changes. In three cases, EPC was due to Rasmussen's Encephalitis (case 1), focal cortical dysplasia (case 2), or remained unknown (case 3). tDCS cycles were administered over 6 to 22 months. The outcomes comprised a reduction of at least 75% in seizure frequency for two patients, and in one case, a complete cessation of severe motor seizures. However, tDCS had no substantial impact on the continuous myoclonus characterizing EPC. No serious side effects were reported. Long-term application of tDCS cycles is well tolerated and can lead to a considerable reduction in disabling seizures in patients with various forms of epilepsy with EPC.
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Affiliation(s)
- M Daoud
- Aix-Marseille Univ, INSERM U1106, Institut de Neurosciences des Systèmes, Marseille, France
| | - C Durelle
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - A Fierain
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - El Youssef N
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - F Wendling
- Univ Rennes, INSERM, LTSI-U1099, Rennes, F-35000, France
| | - G Ruffini
- Neuroelectrics Barcelona, Av. Tibidabo 47 bis, Barcelona, 08035, Spain
| | - P Benquet
- Univ Rennes, INSERM, LTSI-U1099, Rennes, F-35000, France
| | - F Bartolomei
- Aix-Marseille Univ, INSERM U1106, Institut de Neurosciences des Systèmes, Marseille, France.
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France.
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Trofimova AM, Amakhin DV, Postnikova TY, Tiselko VS, Alekseev A, Podoliak E, Gordeliy VI, Chizhov AV, Zaitsev AV. Light-Driven Sodium Pump as a Potential Tool for the Control of Seizures in Epilepsy. Mol Neurobiol 2023:10.1007/s12035-023-03865-z. [PMID: 38114761 DOI: 10.1007/s12035-023-03865-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 12/06/2023] [Indexed: 12/21/2023]
Abstract
The marine flavobacterium Krokinobactereikastus light-driven sodium pump (KR2) generates an outward sodium ion current under 530 nm light stimulation, representing a promising optogenetic tool for seizure control. However, the specifics of KR2 application to suppress epileptic activity have not yet been addressed. In the present study, we investigated the possibility of KR2 photostimulation to suppress epileptiform activity in mouse brain slices using the 4-aminopyrindine (4-AP) model. We injected the adeno-associated viral vector (AAV-PHP.eB-hSyn-KR2-YFP) containing the KR2 sodium pump gene enhanced with appropriate trafficking tags. KR2 expression was observed in the lateral entorhinal cortex and CA1 hippocampus. Using whole-cell patch clamp in mouse brain slices, we show that KR2, when stimulated with LED light, induces a substantial hyperpolarization of entorhinal neurons. However, continuous photostimulation of KR2 does not interrupt ictal discharges in mouse entorhinal cortex slices induced by a solution containing 4-AP. KR2-induced hyperpolarization strongly activates neuronal HCN channels. Consequently, turning off photostimulation resulted in HCN channel-mediated rebound depolarization accompanied by a transient increase in spontaneous network activity. Using low-frequency pulsed photostimulation, we induced the generation of short HCN channel-mediated discharges that occurred in response to the light stimulus being turned off; these discharges reliably interrupt ictal activity. Thus, low-frequency pulsed photostimulation of KR2 can be considered as a potential tool for controlling epileptic seizures.
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Affiliation(s)
- Alina M Trofimova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Dmitry V Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Tatyana Y Postnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Vasilii S Tiselko
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Elizaveta Podoliak
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Bonn, Germany
| | - Valentin I Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Anton V Chizhov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
- MathNeuro Team, Inria Centre at Université Côte d'Azur, Sophia Antipolis, France
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia.
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Nguyen TD, Ishibashi M, Sinha AS, Watanabe M, Kato D, Horiuchi H, Wake H, Fukuda A. Astrocytic NKCC1 inhibits seizures by buffering Cl - and antagonizing neuronal NKCC1 at GABAergic synapses. Epilepsia 2023; 64:3389-3403. [PMID: 37779224 DOI: 10.1111/epi.17784] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/29/2023] [Accepted: 09/29/2023] [Indexed: 10/03/2023]
Abstract
OBJECTIVE A pathological excitatory action of the major inhibitory neurotransmitter γ-aminobutyric acid (GABA) has been observed in epilepsy. Blocking the Cl- importer NKCC1 with bumetanide is expected to reduce the neuronal intracellular Cl- concentration ([Cl- ]i ) and thereby attenuate the excitatory GABA response. Accordingly, several clinical trials of bumetanide for epilepsy were conducted. Although NKCC1 is expressed in both neurons and glial cells, an involvement of glial NKCC1 in seizures has not yet been reported. Astrocytes maintain high [Cl- ]i with NKCC1, and this gradient promotes Cl- efflux via the astrocytic GABAA receptor (GABAA R). This Cl- efflux buffers the synaptic cleft Cl- concentration to maintain the postsynaptic Cl- gradient during intense firing of GABAergic neurons, thereby sustaining its inhibitory action during seizure. In this study, we investigated the function of astrocytic NKCC1 in modulating the postsynaptic action of GABA in acute seizure models. METHODS We used the astrocyte-specific conditional NKCC1 knockout (AstroNKCC1KO) mice. The seizurelike events (SLEs) in CA1 pyramidal neurons were triggered by tetanic stimulation of stratum radiatum in acute hippocampus slices. The SLE underlying GABAA R-mediated depolarization was evaluated by applying the GABAA R antagonist bicuculline. The pilocarpine-induced seizure in vivo was monitored in adult mice by the Racine scale. The SLE duration and tetanus stimulation intensity threshold and seizure behavior in AstroNKCC1KO mice and wild-type (WT) mice were compared. RESULTS The AstroNKCC1KO mice were prone to seizures with lower threshold and longer duration of SLEs and larger GABAA R-mediated depolarization underlying the SLEs, accompanied by higher Racine-scored seizures. Bumetanide reduced these indicators of seizure in AstroNKCC1KO mice (which still express neuronal NKCC1), but not in the WT, both in vitro and in vivo. SIGNIFICANCE Astrocytic NKCC1 inhibits GABA-mediated excitatory action during seizures, whereas neuronal NKCC1 has the converse effect, suggesting opposing actions of bumetanide on these cells.
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Affiliation(s)
- Trong Dao Nguyen
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masaru Ishibashi
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Adya Saran Sinha
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Daisuke Kato
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroshi Horiuchi
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroaki Wake
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Kurki SN, Srinivasan R, Laine J, Virtanen MA, Ala-Kurikka T, Voipio J, Kaila K. Acute neuroinflammation leads to disruption of neuronal chloride regulation and consequent hyperexcitability in the dentate gyrus. Cell Rep 2023; 42:113379. [PMID: 37922309 DOI: 10.1016/j.celrep.2023.113379] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/15/2023] [Accepted: 10/19/2023] [Indexed: 11/05/2023] Open
Abstract
Neuroinflammation is a salient part of diverse neurological and psychiatric pathologies that associate with neuronal hyperexcitability, but the underlying molecular and cellular mechanisms remain to be identified. Here, we show that peripheral injection of lipopolysaccharide (LPS) renders the dentate gyrus (DG) hyperexcitable to perforant pathway stimulation in vivo and increases the internal spiking propensity of dentate granule cells (DGCs) in vitro 24 h post-injection (hpi). In parallel, LPS leads to a prominent downregulation of chloride extrusion via KCC2 and to the emergence of NKCC1-mediated chloride uptake in DGCs under experimental conditions optimized to detect specific changes in transporter efficacy. These data show that acute neuroinflammation leads to disruption of neuronal chloride regulation, which unequivocally results in a loss of GABAergic inhibition in the DGCs, collapsing the gating function of the DG. The present work provides a mechanistic explanation for neuroinflammation-driven hyperexcitability and consequent cognitive disturbance.
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Affiliation(s)
- Samu N Kurki
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland.
| | - Rakenduvadhana Srinivasan
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Jens Laine
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Mari A Virtanen
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Tommi Ala-Kurikka
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland.
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Garcia-Durillo M, Frenguelli BG. Antagonism of P2X7 receptors enhances lorazepam action in delaying seizure onset in an in vitro model of status epilepticus. Neuropharmacology 2023; 239:109647. [PMID: 37459909 DOI: 10.1016/j.neuropharm.2023.109647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/19/2023] [Accepted: 06/24/2023] [Indexed: 08/06/2023]
Abstract
Approximately 30% of patients with status epilepticus (SE) become refractory to two or more antiseizure medications (ASMs). There is thus a real need to identify novel targets against which to develop new ASMs for treating this clinical emergency. Among purinergic receptors, the ionotropic ATP-gated P2X7 receptor (P2X7R) has received attention as a potential ASM target. This study evaluated the effect of the selective P2X7R antagonist A740003 on acute seizures in the dentate gyrus (DG) of hippocampal brain slices, where P2X7Rs are highly expressed, with a view to establishing the potential of P2X7R antagonists as a therapy or adjunct with lorazepam (LZP) in refractory SE. Extracellular electrophysiological recordings were made from the DG of male mouse hippocampal slices. Spontaneous seizure-like events (SLEs) were induced by removing extracellular Mg2+ and sequentially adding the K+ channel blocker 4-aminopyridine and the adenosine A1 receptor antagonist 8-cyclopentyltheophylline, during which the early and late application of A740003 and/or lorazepam was evaluated. Our study revealed that, in the absence of changes in mRNA for P2X7Rs or inflammatory markers, P2X7R antagonism did not reduce the frequency of SLEs. However, A740003 in conjunction with LZP delayed the onset of seizures. Furthermore, our results support the need for employing LZP before seizures become refractory during SE as delayed application of LZP increased seizure frequency. These studies reveal possible sites of intervention that could have a positive impact in patients with high risk of suffering SE.
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Affiliation(s)
| | - Bruno G Frenguelli
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom.
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10
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Morris G, Avoli M, Bernard C, Connor K, de Curtis M, Dulla CG, Jefferys JGR, Psarropoulou C, Staley KJ, Cunningham MO. Can in vitro studies aid in the development and use of antiseizure therapies? A report of the ILAE/AES Joint Translational Task Force. Epilepsia 2023; 64:2571-2585. [PMID: 37642296 DOI: 10.1111/epi.17744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
In vitro preparations (defined here as cultured cells, brain slices, and isolated whole brains) offer a variety of approaches to modeling various aspects of seizures and epilepsy. Such models are particularly amenable to the application of anti-seizure compounds, and consequently are a valuable tool to screen the mechanisms of epileptiform activity, mode of action of known anti-seizure medications (ASMs), and the potential efficacy of putative new anti-seizure compounds. Despite these applications, all disease models are a simplification of reality and are therefore subject to limitations. In this review, we summarize the main types of in vitro models that can be used in epilepsy research, describing key methodologies as well as notable advantages and disadvantages of each. We argue that a well-designed battery of in vitro models can form an effective and potentially high-throughput screening platform to predict the clinical usefulness of ASMs, and that in vitro models are particularly useful for interrogating mechanisms of ASMs. To conclude, we offer several key recommendations that maximize the potential value of in vitro models in ASM screening. This includes the use of multiple in vitro tests that can complement each other, carefully combined with in vivo studies, the use of tissues from chronically epileptic (rather than naïve wild-type) animals, and the integration of human cell/tissue-derived preparations.
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Affiliation(s)
- Gareth Morris
- Division of Neuroscience, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montréal, Quebec, Canada
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Christophe Bernard
- Inserm, INS, Institut de Neurosciences des Systèmes, Aix Marseille Univ, Marseille, France
| | - Kate Connor
- Discipline of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - John G R Jefferys
- Department of Physiology, 2nd Medical School, Motol, Charles University, Prague, Czech Republic
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Caterina Psarropoulou
- Laboratory of Animal and Human Physiology, Department of Biological Applications and Technology, Faculty of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Kevin J Staley
- Neurology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mark O Cunningham
- Discipline of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
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11
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Graham RT, Parrish RR, Alberio L, Johnson EL, Owens L, Trevelyan AJ. Optogenetic stimulation reveals a latent tipping point in cortical networks during ictogenesis. Brain 2023; 146:2814-2827. [PMID: 36572952 PMCID: PMC10316782 DOI: 10.1093/brain/awac487] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 11/17/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022] Open
Abstract
Brain-state transitions are readily apparent from changes in brain rhythms,1 but are difficult to predict, suggestive that the underlying cause is latent to passive recording methods. Among the most important transitions, clinically, are the starts of seizures. We here show that an 'active probing' approach may have several important benefits for epileptic management, including by helping predict these transitions. We used mice expressing the optogenetic actuator, channelrhodopsin, in pyramidal cells, allowing this population to be stimulated in isolation. Intermittent stimulation at frequencies as low as 0.033 Hz (period = 30 s) delayed the onset of seizure-like events in an acute brain slice model of ictogenesis, but the effect was lost if stimulation was delivered at even lower frequencies (1/min). Notably, active probing additionally provides advance indication of when seizure-like activity is imminent, revealed by monitoring the postsynaptic response to stimulation. The postsynaptic response, recorded extracellularly, showed an all-or-nothing change in both amplitude and duration, a few hundred seconds before seizure-like activity began-a sufficient length of time to provide a helpful warning of an impending seizure. The change in the postsynaptic response then persisted for the remainder of the recording, indicative of a state change from a pre-epileptic to a pro-epileptic network. This occurred in parallel with a large increase in the stimulation-triggered Ca2+ entry into pyramidal dendrites, and a step increase in the number of evoked postsynaptic action potentials, both consistent with a reduction in the threshold for dendritic action potentials. In 0 Mg2+ bathing media, the reduced threshold was not associated with changes in glutamatergic synaptic function, nor of GABAergic release from either parvalbumin or somatostatin interneurons, but simulations indicate that the step change in the optogenetic response can instead arise from incremental increases in intracellular [Cl-]. The change in the response to stimulation was replicated by artificially raising intracellular [Cl-], using the optogenetic chloride pump, halorhodopsin. By contrast, increases in extracellular [K+] cannot account for the firing patterns in the response to stimulation, although this, and other cellular changes, may contribute to ictal initiation in other circumstances. We describe how these various cellular changes form a synergistic network of positive feedback mechanisms, which may explain the precipitous nature of seizure onset. This model of seizure initiation draws together several major lines of epilepsy research as well as providing an important proof-of-principle regarding the utility of open-loop brain stimulation for clinical management of the condition.
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Affiliation(s)
- Robert T Graham
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - R Ryley Parrish
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Laura Alberio
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Emily L Johnson
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Laura Owens
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew J Trevelyan
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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12
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Stöber TM, Batulin D, Triesch J, Narayanan R, Jedlicka P. Degeneracy in epilepsy: multiple routes to hyperexcitable brain circuits and their repair. Commun Biol 2023; 6:479. [PMID: 37137938 PMCID: PMC10156698 DOI: 10.1038/s42003-023-04823-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 04/06/2023] [Indexed: 05/05/2023] Open
Abstract
Due to its complex and multifaceted nature, developing effective treatments for epilepsy is still a major challenge. To deal with this complexity we introduce the concept of degeneracy to the field of epilepsy research: the ability of disparate elements to cause an analogous function or malfunction. Here, we review examples of epilepsy-related degeneracy at multiple levels of brain organisation, ranging from the cellular to the network and systems level. Based on these insights, we outline new multiscale and population modelling approaches to disentangle the complex web of interactions underlying epilepsy and to design personalised multitarget therapies.
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Affiliation(s)
- Tristan Manfred Stöber
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, 44801, Bochum, Germany
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, 60590, Frankfurt, Germany
| | - Danylo Batulin
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- CePTER - Center for Personalized Translational Epilepsy Research, Goethe University, 60590, Frankfurt, Germany
- Faculty of Computer Science and Mathematics, Goethe University, 60486, Frankfurt, Germany
| | - Jochen Triesch
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Peter Jedlicka
- ICAR3R - Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus Liebig University Giessen, 35390, Giessen, Germany.
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, 60590, Frankfurt am Main, Germany.
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13
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Călin A, Waseem T, Raimondo JV, Newey SE, Akerman CJ. A genetically targeted ion sensor reveals distinct seizure-related chloride and pH dynamics in GABAergic interneuron populations. iScience 2023; 26:106363. [PMID: 37034992 PMCID: PMC10074576 DOI: 10.1016/j.isci.2023.106363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 02/03/2023] [Accepted: 03/05/2023] [Indexed: 03/12/2023] Open
Abstract
Intracellular chloride and pH play fundamental roles in determining a neuron's synaptic inhibition and excitability. Yet it has been difficult to measure changes in these ions during periods of heightened network activity, such as occur in epilepsy. Here we develop a version of the fluorescent reporter, ClopHensorN, to enable simultaneous quantification of chloride and pH in genetically defined neurons during epileptiform activity. We compare pyramidal neurons to the major GABAergic interneuron subtypes in the mouse hippocampus, which express parvalbumin (PV), somatostatin (SST), or vasoactive intestinal polypeptide (VIP). Interneuron populations exhibit higher baseline chloride, with PV interneurons exhibiting the highest levels. During an epileptiform discharge, however, all subtypes converge upon a common elevated chloride level. Concurrent with these dynamics, epileptiform activity leads to different degrees of intracellular acidification, which reflect baseline pH. Thus, a new optical tool for dissociating chloride and pH reveals neuron-specific ion dynamics during heightened network activity.
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Affiliation(s)
- Alexandru Călin
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Tatiana Waseem
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Joseph V. Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Sarah E. Newey
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Colin J. Akerman
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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14
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Jarvis R, Josephine Ng SF, Nathanson AJ, Cardarelli RA, Abiraman K, Wade F, Evans-Strong A, Fernandez-Campa MP, Deeb TZ, Smalley JL, Jamier T, Gurrell IK, McWilliams L, Kawatkar A, Conway LC, Wang Q, Burli RW, Brandon NJ, Chessell IP, Goldman AJ, Maguire JL, Moss SJ. Direct activation of KCC2 arrests benzodiazepine refractory status epilepticus and limits the subsequent neuronal injury in mice. Cell Rep Med 2023; 4:100957. [PMID: 36889319 PMCID: PMC10040380 DOI: 10.1016/j.xcrm.2023.100957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/17/2022] [Accepted: 02/06/2023] [Indexed: 03/09/2023]
Abstract
Hyperpolarizing GABAAR currents, the unitary events that underlie synaptic inhibition, are dependent upon efficient Cl- extrusion, a process that is facilitated by the neuronal specific K+/Cl- co-transporter KCC2. Its activity is also a determinant of the anticonvulsant efficacy of the canonical GABAAR-positive allosteric: benzodiazepines (BDZs). Compromised KCC2 activity is implicated in the pathophysiology of status epilepticus (SE), a medical emergency that rapidly becomes refractory to BDZ (BDZ-RSE). Here, we have identified small molecules that directly bind to and activate KCC2, which leads to reduced neuronal Cl- accumulation and excitability. KCC2 activation does not induce any overt effects on behavior but prevents the development of and terminates ongoing BDZ-RSE. In addition, KCC2 activation reduces neuronal cell death following BDZ-RSE. Collectively, these findings demonstrate that KCC2 activation is a promising strategy to terminate BDZ-resistant seizures and limit the associated neuronal injury.
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Affiliation(s)
- Rebecca Jarvis
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Shu Fun Josephine Ng
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Anna J Nathanson
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Ross A Cardarelli
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Krithika Abiraman
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Fergus Wade
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Aidan Evans-Strong
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Marina P Fernandez-Campa
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Tarek Z Deeb
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Joshua L Smalley
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Tanguy Jamier
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Ian K Gurrell
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Lisa McWilliams
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | - Aarti Kawatkar
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Boston, MA, USA
| | - Leslie C Conway
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Qi Wang
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Boston, MA, USA
| | - Roland W Burli
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Nicholas J Brandon
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Boston, MA, USA
| | - Iain P Chessell
- Discovery, Neuroscience, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Aaron J Goldman
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA; Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1 6BT, UK.
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15
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Dossi E, Huberfeld G. GABAergic circuits drive focal seizures. Neurobiol Dis 2023; 180:106102. [PMID: 36977455 DOI: 10.1016/j.nbd.2023.106102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/10/2023] [Accepted: 03/23/2023] [Indexed: 03/28/2023] Open
Abstract
Epilepsy is based on abnormal neuronal activities that have historically been suggested to arise from an excess of excitation and a defect of inhibition, or in other words from an excessive glutamatergic drive not balanced by GABAergic activity. More recent data however indicate that GABAergic signaling is not defective at focal seizure onset and may even be actively involved in seizure generation by providing excitatory inputs. Recordings of interneurons revealed that they are active at seizure initiation and that their selective and time-controlled activation using optogenetics triggers seizures in a more general context of increased excitability. Moreover, GABAergic signaling appears to be mandatory at seizure onset in many models. The main pro-ictogenic effect of GABAergic signaling is the depolarizing action of GABAA conductance which may occur when an excessive GABAergic activity causes Cl- accumulation in neurons. This process may combine with background dysregulation of Cl-, well described in epileptic tissues. Cl- equilibrium is maintained by (Na+)/K+/Cl- co-transporters, which can be defective and therefore favor the depolarizing effects of GABA. In addition, these co-transporters further contribute to this effect as they mediate K+ outflow together with Cl- extrusion, a process that is responsible for K+ accumulation in the extracellular space and subsequent increase of local excitability. The role of GABAergic signaling in focal seizure generation is obvious but its complex dynamics and balance between GABAA flux polarity and local excitability still remain to be established, especially in epileptic tissues where receptors and ion regulators are disrupted and in which GABAergic signaling rather plays a 2 faces Janus role.
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16
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Wickham J, Ledri M, Andersson M, Kokaia M. Cell-specific switch for epileptiform activity: critical role of interneurons in the mouse subicular network. Cereb Cortex 2023; 33:6171-6183. [PMID: 36611229 PMCID: PMC10183737 DOI: 10.1093/cercor/bhac493] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 01/09/2023] Open
Abstract
During epileptic seizures, neuronal network activity is hyper synchronized whereby GABAergic parvalbumin-interneurons may have a key role. Previous studies have mostly utilized 4-aminopyridine to induce epileptiform discharges in brain slices from healthy animals. However, it is not clear if the seizure-triggering ability of parvalbumin-interneurons also holds true without the use of external convulsive agents. Here, we investigate whether synchronized activation of parvalbumin-interneurons or principal cells can elicit epileptiform discharges in subiculum slices of epileptic mice. We found that selective synchronized activation of parvalbumin-interneurons or principal cells with optogenetics do not result in light-induced epileptiform discharges (LIEDs) neither in epileptic nor in normal brain slices. Adding 4-aminopyridine to slices, activation of parvalbumin-interneurons still failed to trigger LIEDs. In contrast, such activation of principal neurons readily generated LIEDs with features resembling afterdischarges. When GABAA receptor blocker was added to the perfusion medium, the LIEDs were abolished. These results demonstrate that in subiculum, selective synchronized activation of principal excitatory neurons can trigger epileptiform discharges by recruiting a large pool of downstream interneurons. This study also suggests region-specific role of principal neurons and interneurons in ictogenesis, opening towards differential targeting of specific brain areas for future treatment strategies tailored for individual patients with epilepsy.
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Affiliation(s)
- J Wickham
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Ledri
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Andersson
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Kokaia
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
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17
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Neurotoxicity evoked by organophosphates and available countermeasures. Arch Toxicol 2023; 97:39-72. [PMID: 36335468 DOI: 10.1007/s00204-022-03397-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022]
Abstract
Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.
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18
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Trevelyan AJ, Graham RT, Parrish RR, Codadu NK. Synergistic Positive Feedback Mechanisms Underlying Seizure Initiation. Epilepsy Curr 2023; 23:38-43. [PMID: 36923333 PMCID: PMC10009126 DOI: 10.1177/15357597221127163] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Investigations into seizure initiation, in recent years, have focused almost entirely upon alterations of interneuronal function, chloride homeostasis, and extracellular potassium levels. In contrast, little attention has been directed toward a possible role of dendritic plateau potentials in the actual ictogenic transition, despite a substantial literature dating back 40 years regarding its importance generally in epilepsy. Here, we argue that an increase in dendritic excitability, coordinated across the population of pyramidal cells, is a key stage in ictogenesis.
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Affiliation(s)
- Andrew J. Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Robert T. Graham
- Queen Square Institute of Neurology, University College London, United Kingdom
| | - R. Ryley Parrish
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, USA
| | - Neela K. Codadu
- Queen Square Institute of Neurology, University College London, United Kingdom
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19
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Tolu-Bolaji OO, Sojinu SO, Okedere AP, Ajani OO. A review on the chemistry and pharmacological properties of benzodiazepine motifs in drug design. ARAB JOURNAL OF BASIC AND APPLIED SCIENCES 2022. [DOI: 10.1080/25765299.2022.2117677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Affiliation(s)
- Olayinka O. Tolu-Bolaji
- Department of Chemistry, College of Physical Sciences, Federal University of Agriculture, Abeokuta, Abeokuta, Ogun State, Nigeria
| | - Samuel O. Sojinu
- Department of Chemistry, College of Physical Sciences, Federal University of Agriculture, Abeokuta, Abeokuta, Ogun State, Nigeria
| | - Adebola P. Okedere
- Department of Chemistry, College of Physical Sciences, Federal University of Agriculture, Abeokuta, Abeokuta, Ogun State, Nigeria
| | - Olayinka O. Ajani
- Department of Chemistry, College of Science and Technology, Covenant University, Ota, Ogun State, Nigeria
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20
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Fisch U, Jünger AL, Hert L, Rüegg S, Sutter R. Therapeutically induced EEG burst-suppression pattern to treat refractory status epilepticus—what is the evidence? ZEITSCHRIFT FÜR EPILEPTOLOGIE 2022. [DOI: 10.1007/s10309-022-00539-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractCurrent guidelines advocate to treat refractory status epilepticus (RSE) with continuously administered anesthetics to induce an artificial coma if first- and second-line antiseizure drugs have failed to stop seizure activity. A common surrogate for monitoring the depth of the artificial coma is the appearance of a burst-suppression pattern (BS) in the EEG. This review summarizes the current knowledge on the origin and neurophysiology of the BS phenomenon as well as the evidence from the literature for the presumed benefit of BS as therapy in adult patients with RSE.
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21
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Proskurina EY, Zaitsev AV. Regulation of Potassium and Chloride Concentrations in Nervous Tissue as a Method of Anticonvulsant Therapy. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022050015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Under some pathological conditions, such as pharmacoresistant
epilepsy, status epilepticus or certain forms of genetic abnormalities,
spiking activity of GABAergic interneurons may enhance excitation
processes in neuronal circuits and provoke the generation of ictal
discharges. As a result, anticonvulsants acting on the GABAergic
system may be ineffective or even increase seizure activity. This
paradoxical effect of the inhibitory system is due to ionic imbalances
in nervous tissue. This review addresses the mechanisms of ictal
discharge initiation in neuronal networks due to the imbalance of
chloride and potassium ions, as well as possible ways to regulate
ionic concentrations. Both the enhancement (or attenuation) of the
activity of certain neuronal ion transporters and ion pumps and
their additional expression via gene therapy can be effective in
suppressing seizure activity caused by ionic imbalances. The Na+–K+-pump,
NKCC1 and KCC2 cotransporters are important for maintaining proper
K+ and Cl– concentrations
in nervous tissue, having been repeatedly considered as pharmacological
targets for antiepileptic exposures. Further progress in this direction
is hampered by the lack of sufficiently selective pharmacological
tools and methods for providing effective drug delivery to the epileptic
focus. The use of the gene therapy techniques, such as overexpressing
of the KCC2 transporter in the epileptic focus, seems to be a more promising
approach. Another possible direction could be the use of optogenetic
tools, namely specially designed light-activated ion pumps or ion
channels. In this case, photon energy can be used to create the
required gradients of chloride and potassium ions, although these
methods also have significant limitations which complicate their
rapid introduction into medicine.
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22
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Lopez-Sola E, Sanchez-Todo R, Lleal È, Köksal Ersöz E, Yochum M, Makhalova J, Mercadal B, Guasch M, Salvador R, Lozano-Soldevilla D, Modolo J, Bartolomei F, Wendling F, Benquet P, Ruffini G. A personalizable autonomous neural mass model of epileptic seizures. J Neural Eng 2022; 19. [PMID: 35995031 DOI: 10.1088/1741-2552/ac8ba8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/22/2022] [Indexed: 11/11/2022]
Abstract
Work in the last two decades has shown that neural mass models (NMM) can realistically reproduce and explain epileptic seizure transitions as recorded by electrophysiological methods (EEG, SEEG). In previous work, advances were achieved by increasing excitation and heuristically varying network inhibitory coupling parameters in the models. Based on these early studies, we provide a laminar NMM capable of realistically reproducing the electrical activity recorded by SEEG in the epileptogenic zone during interictal to ictal states. With the exception of the external noise input into the pyramidal cell population, the model dynamics are autonomous. By setting the system at a point close to bifurcation, seizure-like transitions are generated, including pre-ictal spikes, low voltage fast activity, and ictal rhythmic activity. A novel element in the model is a physiologically motivated algorithm for chloride dynamics: the gain of GABAergic post-synaptic potentials is modulated by the pathological accumulation of chloride in pyramidal cells due to high inhibitory input and/or dysfunctional chloride transport. In addition, in order to simulate SEEG signals for comparison with real seizure recordings, the NMM is embedded first in a layered model of the neocortex and then in a realistic physical model. We compare modeling results with data from four epilepsy patient cases. By including key pathophysiological mechanisms, the proposed framework captures succinctly the electrophysiological phenomenology observed in ictal states, paving the way for robust personalization methods based on NMMs.
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Affiliation(s)
- Edmundo Lopez-Sola
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Barcelona, 08035, SPAIN
| | - Roser Sanchez-Todo
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Catalunya, 08035, SPAIN
| | - Èlia Lleal
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Catalunya, 08035, SPAIN
| | - Elif Köksal Ersöz
- LTSI, Universite de Rennes 1, Campus de Beaulieu, Rennes, Bretagne, 35065, FRANCE
| | - Maxime Yochum
- LTSI, Universite de Rennes 1, Campus Beaulieu, Rennes, Bretagne, 35065, FRANCE
| | - Julia Makhalova
- Neurophysiologie clinique, Service d'Epileptologie et de Rythmologie Cerebrale, Assistance Publique Hopitaux de Marseille, Hôpital de la Timone, Marseille, Provence-Alpes-Côte d'Azu, 13354, FRANCE
| | - Borja Mercadal
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Catalunya, 08035, SPAIN
| | - Maria Guasch
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Barcelona, 08035, SPAIN
| | - Ricardo Salvador
- Neuroelectrics Barcelona SL, Av Tibidabo, 47bis, Barcelona, Barcelona, Catalunya, 08035, SPAIN
| | | | - Julien Modolo
- LTSI, Universite de Rennes 1, Campus de Beaulieu, Rennes, Bretagne, 35065, FRANCE
| | - Fabrice Bartolomei
- Neurophysiologie clinique, Service d'Epileptologie et de Rythmologie Cerebrale, Assistance Publique Hopitaux de Marseille, Hôpital de la Timone, Marseille, Provence-Alpes-Côte d'Azu, 13354, FRANCE
| | - Fabrice Wendling
- LTSI, Universite de Rennes 1, Campus Beaulieu, Rennes, Bretagne, 35065, FRANCE
| | - Pascal Benquet
- LTSI, Universite de Rennes 1, Campus Beaulieu, Rennes, Bretagne, 35065, FRANCE
| | - Giulio Ruffini
- Neuroelectrics Barcelona SL, Avda Tibidabo, 47 bis, Barcelona, Catalunya, 08035, SPAIN
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23
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Li X, Zhang H, Lai H, Wang J, Wang W, Yang X. High-Frequency Oscillations and Epileptogenic Network. Curr Neuropharmacol 2022; 20:1687-1703. [PMID: 34503414 PMCID: PMC9881061 DOI: 10.2174/1570159x19666210908165641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/26/2021] [Accepted: 08/31/2021] [Indexed: 11/22/2022] Open
Abstract
Epilepsy is a network disease caused by aberrant neocortical large-scale connectivity spanning regions on the scale of several centimeters. High-frequency oscillations, characterized by the 80-600 Hz signals in electroencephalography, have been proven to be a promising biomarker of epilepsy that can be used in assessing the severity and susceptibility of epilepsy as well as the location of the epileptogenic zone. However, the presence of a high-frequency oscillation network remains a topic of debate as high-frequency oscillations have been previously thought to be incapable of propagation, and the relationship between high-frequency oscillations and the epileptogenic network has rarely been discussed. Some recent studies reported that high-frequency oscillations may behave like networks that are closely relevant to the epileptogenic network. Pathological highfrequency oscillations are network-driven phenomena and elucidate epileptogenic network development; high-frequency oscillations show different characteristics coincident with the epileptogenic network dynamics, and cross-frequency coupling between high-frequency oscillations and other signals may mediate the generation and propagation of abnormal discharges across the network.
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Affiliation(s)
- Xiaonan Li
- Bioland Laboratory, Guangzhou, China; ,Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | | | | | - Jiaoyang Wang
- Bioland Laboratory, Guangzhou, China; ,Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Wei Wang
- Bioland Laboratory, Guangzhou, China; ,Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Xiaofeng Yang
- Bioland Laboratory, Guangzhou, China; ,Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China,Address correspondence to this author at the Bioland Laboratory, Guangzhou, China; Tel: 86+ 18515855127; E-mail:
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24
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Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2. J Mol Neurosci 2022; 72:1500-1515. [PMID: 35819636 DOI: 10.1007/s12031-022-02041-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 06/07/2022] [Indexed: 10/17/2022]
Abstract
Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABAA receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABAA receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K+-Cl--cotransporter (KCC2) to the alterations in the Cl- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.
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25
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Cerne R, Lippa A, Poe MM, Smith JL, Jin X, Ping X, Golani LK, Cook JM, Witkin JM. GABAkines - Advances in the discovery, development, and commercialization of positive allosteric modulators of GABA A receptors. Pharmacol Ther 2022; 234:108035. [PMID: 34793859 PMCID: PMC9787737 DOI: 10.1016/j.pharmthera.2021.108035] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 11/08/2021] [Indexed: 12/25/2022]
Abstract
Positive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABAA receptor potentiation for therapeutic gain in neurology and psychiatry.
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Affiliation(s)
- Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | | | - Jodi L. Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA
| | - Xiaoming Jin
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Xingjie Ping
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Lalit K. Golani
- Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - James M. Cook
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeffrey M. Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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26
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Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus. Nat Rev Neurol 2022; 18:428-441. [PMID: 35538233 DOI: 10.1038/s41582-022-00664-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2022] [Indexed: 11/08/2022]
Abstract
Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABAA receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.
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27
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Singh T, Batabyal T, Kapur J. Neuronal circuits sustaining neocortical-injury-induced status epilepticus. Neurobiol Dis 2022; 165:105633. [PMID: 35065250 PMCID: PMC8860889 DOI: 10.1016/j.nbd.2022.105633] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 01/04/2022] [Accepted: 01/16/2022] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVES Acute injuries or insults to the cortex, such as trauma, subarachnoid hemorrhage, lobar hemorrhage, can cause seizures or status epilepticus(SE). Neocortical SE is associated with coma, worse prognosis, delayed recovery, and the development of epilepsy. The anatomical structures progressively recruited during neocortical-onset status epilepticus (SE) is unknown. Therefore, we constructed large-scale maps of brain regions active during neocortical SE. METHODS We used a neocortical injury-induced SE mouse model. We implanted cobalt (Co) in the right supplementary motor cortex (M2). We 16 h later administered a homocysteine injection (845 mg/kg, intraperitoneal) to C57Bl/6 J mice to induce SE and monitored it by video and EEG. We harvested animals for 1 h (early-stage) and 2 h (late-stage) following homocysteine injections. To construct activation maps, we immunolabeled whole-brain sections for cFos and NeuN, imaged them using a confocal microscope and quantified cFos immunoreactivity (IR). RESULTS SE in the early phase consisted of discrete, focal intermittent seizures, which became continuous and bilateral in the late stage. In this early stage, cFos IR was primarily observed in the right hemisphere, ipsilateral to the Co lesion, specifically in the motor cortex, retrosplenial cortex, somatosensory cortex, anterior cingulate cortex, lateral and medial septal nuclei, and amygdala. We observed bilateral cFos IR in brain regions during the late stage, indicating the bilateral spread of focal seizures. We found increased cFOS IR in the bilateral somatosensory cortex and the motor cortex and subcortical regions, including the amygdala, thalamus, and hypothalamus. There was noticeably different, intense cFos IR in the bilateral hippocampus compared to the early stage. In addition, there was higher activity in the cortex ipsilateral to the seizure focus during the late stage compared with the early one. CONCLUSION We present a large-scale, high-resolution map of seizure spread during neocortical injury-induced SE. Cortico-cortical and cortico subcortical re-entrant circuits sustain neocortical SE. Neuronal loss following neocortical SE, distant from the neocortical focus, may result from seizures.
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Affiliation(s)
- Tanveer Singh
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - Tamal Batabyal
- UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA; UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA; Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA.
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28
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Lodovichi C, Ratto GM, Trevelyan AJ, Arosio D. Genetically encoded sensors for Chloride concentration. J Neurosci Methods 2022; 368:109455. [PMID: 34952088 DOI: 10.1016/j.jneumeth.2021.109455] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 12/12/2022]
Abstract
Insights into chloride regulation in neurons have come slowly, but they are likely to be critical for our understanding of how the brain works. The reason is that the intracellular Cl- level ([Cl-]i) is the key determinant of synaptic inhibitory function, and this in turn dictates all manner of neuronal network function. The true impact on the network will only be apparent, however, if Cl- is measured at many locations at once (multiple neurons, and also across the subcellular compartments of single neurons), which realistically, can only be achieved using imaging. The development of genetically-encoded anion biosensors (GABs) brings the additional benefit that Cl- imaging may be done in identified cell-classes and hopefully in subcellular compartments. Here, we describe the historical background and motivation behind the development of these sensors and how they have been used so far. There are, however, still major limitations for their use, the most important being the fact that all GABs are sensitive to both pH and Cl-. Disambiguating the two signals has proved a major challenge, but there are potential solutions; notable among these is ClopHensor, which has now been developed for in vivo measurements of both ion species. We also speculate on how these biosensors may yet be improved, and how this could advance our understanding of Cl- regulation and its impact on brain function.
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Affiliation(s)
- Claudia Lodovichi
- Neuroscience Institute-CNR, Depart. Biomedical Sciences, Unipd, Padova, Veneto Institute of Molecular Medicine, Padova Neuroscience Center, Padova, Italy.
| | - Gian Michele Ratto
- National Enterprise for nanoScience and nanoTechnology (NEST), Istituto Nanoscienze, Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniele Arosio
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Biofisica, 38123 Trento, Italy.
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29
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Chizhov AV, Amakhin DV, Smirnova EY, Zaitsev AV. Ictal wavefront propagation in slices and simulations with conductance-based refractory density model. PLoS Comput Biol 2022; 18:e1009782. [PMID: 35041661 PMCID: PMC8797236 DOI: 10.1371/journal.pcbi.1009782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/28/2022] [Accepted: 12/21/2021] [Indexed: 12/04/2022] Open
Abstract
The mechanisms determining ictal discharge (ID) propagation are still not clear. In the present study, we aimed to examine these mechanisms in animal and mathematical models of epileptiform activity. Using double-patch and extracellular potassium ion concentration recordings in rat hippocampal-cortical slices, we observed that IDs moved at a speed of about 1 mm/s or less. The mechanisms of such slow propagation have been studied with a mathematical, conductance-based refractory density (CBRD) model that describes the GABA- and glutamatergic neuronal populations’ interactions and ion dynamics in brain tissue. The modeling study reveals two main factors triggerring IDs: (i) increased interneuronal activity leading to chloride ion accumulation and a consequent depolarizing GABAergic effect and (ii) the elevation of extracellular potassium ion concentration. The local synaptic transmission followed by local potassium ion extrusion and GABA receptor-mediated chloride ion accumulation underlies the ID wavefront’s propagation. In contrast, potassium ion diffusion in the extracellular space is slower and does not affect ID’s speed. The short discharges, constituting the ID, propagate much faster than the ID front. The accumulation of sodium ions inside neurons due to their hyperactivity and glutamatergic currents boosts the Na+/K+ pump, which terminates the ID. Knowledge of the mechanism of ID generation and propagation contributes to the development of new treatments against epilepsy. During an epileptic seizure, neuronal excitation spreads across the brain tissue and is accompanied by significant changes in ionic concentrations. Ictal discharge front spreads at low speeds, less than 1 mm/s. Mechanisms underlying this phenomenon are not yet well understood. We study these mechanisms using electrophysiological recordings in brain slices and computer simulations. Our detailed biophysical model describing neuronal populations’ interaction, spatial propagation, and ionic dynamics reproduces the generation and propagation of spontaneously repeating ictal discharges. The simulations are consistent with our recordings of the electrical activity and the extracellular potassium ion concentration. We distinguished between the two alternative mechanisms of the ictal wavefront propagation: (i) the diffusion of potassium ions released from excited neurons, which depolarizes distant neurons and thus supports excitation, and (ii) the axonal spread of excitation followed by the local extracellular potassium ion accumulation that supports the excitation. Our simulations provide evidence in favor of the latter mechanism. Our experiment-based modeling contributes to a mathematical description of brain tissue functioning and potentially contributes to developing new treatments against epilepsy.
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Affiliation(s)
- Anton V. Chizhov
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- * E-mail:
| | - Dmitry V. Amakhin
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Elena Yu. Smirnova
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Saint Petersburg, Russia
| | - Aleksey V. Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
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30
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Kilb W. When Are Depolarizing GABAergic Responses Excitatory? Front Mol Neurosci 2021; 14:747835. [PMID: 34899178 PMCID: PMC8651619 DOI: 10.3389/fnmol.2021.747835] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
The membrane responses upon activation of GABA(A) receptors critically depend on the intracellular Cl− concentration ([Cl−]i), which is maintained by a set of transmembrane transporters for Cl−. During neuronal development, but also under several pathophysiological conditions, the prevailing expression of the Cl− loader NKCC1 and the low expression of the Cl− extruder KCC2 causes elevated [Cl−]i, which result in depolarizing GABAergic membrane responses. However, depolarizing GABAergic responses are not necessarily excitatory, as GABA(A) receptors also reduces the input resistance of neurons and thereby shunt excitatory inputs. To summarize our knowledge on the effect of depolarizing GABA responses on neuronal excitability, this review discusses theoretical considerations and experimental studies illustrating the relation between GABA conductances, GABA reversal potential and neuronal excitability. In addition, evidences for the complex spatiotemporal interaction between depolarizing GABAergic and glutamatergic inputs are described. Moreover, mechanisms that influence [Cl−]i beyond the expression of Cl− transporters are presented. And finally, several in vitro and in vivo studies that directly investigated whether GABA mediates excitation or inhibition during early developmental stages are summarized. In summary, these theoretical considerations and experimental evidences suggest that GABA can act as inhibitory neurotransmitter even under conditions that maintain substantial depolarizing membrane responses.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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31
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Mackenzie-Gray Scott CA, Parrish RR, Walsh DA, Racca C, Cowell RM, Treveylan AJ. PV-specific loss of the transcriptional coactivator PGC-1α slows down the evolution of epileptic activity in an acute ictogenic model. J Neurophysiol 2021; 127:86-98. [PMID: 34788174 PMCID: PMC8721902 DOI: 10.1152/jn.00295.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The transcriptional coactivator, PGC-1α (peroxisome proliferator-activated receptor γ coactivator 1α), plays a key role in coordinating energy requirement within cells. Its importance is reflected in the growing number of psychiatric and neurological conditions that have been associated with reduced PGC-1α levels. In cortical networks, PGC-1α is required for the induction of parvalbumin (PV) expression in interneurons, and PGC-1α deficiency affects synchronous GABAergic release. It is unknown, however, how this affects cortical excitability. We show here that knocking down PGC-1α specifically in the PV-expressing cells (PGC-1αPV−/−) blocks the activity-dependent regulation of the synaptic proteins, SYT2 and CPLX1. More surprisingly, this cell class-specific knockout of PGC-1α appears to have a novel antiepileptic effect, as assayed in brain slices bathed in 0 Mg2+ media. The rate of occurrence of preictal discharges developed approximately equivalently in wild-type and PGC-1αPV−/− brain slices, but the intensity of these discharges was lower in PGC-1αPV−/− slices, as evident from the reduced power in the γ range and reduced firing rates in both PV interneurons and pyramidal cells during these discharges. Reflecting this reduced intensity in the preictal discharges, the PGC-1αPV−/− brain slices experienced many more discharges before transitioning into a seizure-like event. Consequently, there was a large increase in the latency to the first seizure-like event in brain slices lacking PGC-1α in PV interneurons. We conclude that knocking down PGC-1α limits the range of PV interneuron firing and this slows the pathophysiological escalation during ictogenesis. NEW & NOTEWORTHY Parvalbumin expressing interneurons are considered to play an important role in regulating cortical activity. We were surprised, therefore, to find that knocking down the transcriptional coactivator, PGC-1α, specifically in this class of interneurons appears to slow ictogenesis. This anti-ictogenic effect is associated with reduced activity in preictal discharges, but with a far longer period of these discharges before the first seizure-like events finally start. Thus, PGC-1α knockdown may promote schizophrenia while reducing epileptic tendencies.
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Affiliation(s)
| | - Robert Ryley Parrish
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Darren A Walsh
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Claudia Racca
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Rita M Cowell
- Department of Neuroscience, Drug Discovery Division at Southern Research, Birmingham, AL, United States.,Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Andrew J Treveylan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
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32
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Gorman KM, Peters CH, Lynch B, Jones L, Bassett DS, King MD, Ruben PC, Rosch RE. Persistent sodium currents in SCN1A developmental and degenerative epileptic dyskinetic encephalopathy. Brain Commun 2021; 3:fcab235. [PMID: 34755109 PMCID: PMC8568850 DOI: 10.1093/braincomms/fcab235] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/15/2021] [Accepted: 06/21/2021] [Indexed: 11/14/2022] Open
Abstract
Pathogenic variants in the voltage-gated sodium channel gene (SCN1A) are amongst the most common genetic causes of childhood epilepsies. There is considerable heterogeneity in both the types of causative variants and associated phenotypes; a recent expansion of the phenotypic spectrum of SCN1A associated epilepsies now includes an early onset severe developmental and epileptic encephalopathy with regression and a hyperkinetic movement disorder. Herein, we report a female with a developmental and degenerative epileptic-dyskinetic encephalopathy, distinct and more severe than classic Dravet syndrome. Clinical diagnostics indicated a paternally inherited c.5053G>T; p. A1685S variant of uncertain significance in SCN1A. Whole-exome sequencing detected a second de novo mosaic (18%) c.2345G>A; p. T782I likely pathogenic variant in SCN1A (maternal allele). Biophysical characterization of both mutant channels in a heterologous expression system identified gain-of-function effects in both, with a milder shift in fast inactivation of the p. A1685S channels; and a more severe persistent sodium current in the p. T782I. Using computational models, we show that large persistent sodium currents induce hyper-excitability in individual cortical neurons, thus relating the severe phenotype to the empirically quantified sodium channel dysfunction. These findings further broaden the phenotypic spectrum of SCN1A associated epilepsies and highlight the importance of testing for mosaicism in epileptic encephalopathies. Detailed biophysical evaluation and computational modelling further highlight the role of gain-of-function variants in the pathophysiology of the most severe phenotypes associated with SCN1A.
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Affiliation(s)
- Kathleen M Gorman
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Colin H Peters
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Physiology and Biophysics, University of Colorado, Denver, CO, USA
| | - Bryan Lynch
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Laura Jones
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Dani S Bassett
- Departments of Bioengineering, Electrical & Systems Engineering, Physics & Astronomy, Neurology, and Psychiatry, University of Pennsylvania, Philadelphia, PA, USA.,Santa Fe Institute, Santa Fe, NM, USA
| | - Mary D King
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Richard E Rosch
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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Amakhin DV, Soboleva EB, Chizhov AV, Zaitsev AV. Insertion of Calcium-Permeable AMPA Receptors during Epileptiform Activity In Vitro Modulates Excitability of Principal Neurons in the Rat Entorhinal Cortex. Int J Mol Sci 2021; 22:12174. [PMID: 34830051 PMCID: PMC8621524 DOI: 10.3390/ijms222212174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/05/2021] [Accepted: 11/07/2021] [Indexed: 12/19/2022] Open
Abstract
Epileptic activity leads to rapid insertion of calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (CP-AMPARs) into the synapses of cortical and hippocampal glutamatergic neurons, which generally do not express them. The physiological significance of this process is not yet fully understood; however, it is usually assumed to be a pathological process that augments epileptic activity. Using whole-cell patch-clamp recordings in rat entorhinal cortex slices, we demonstrate that the timing of epileptiform discharges, induced by 4-aminopyridine and gabazine, is determined by the shunting effect of Ca2+-dependent slow conductance, mediated predominantly by K+-channels. The blockade of CP-AMPARs by IEM-1460 eliminates this extra conductance and consequently increases the rate of discharge generation. The blockade of NMDARs reduced the additional conductance to a lesser extent than the blockade of CP-AMPARs, indicating that CP-AMPARs are a more significant source of intracellular Ca2+. The study's main findings were implemented in a mathematical model, which reproduces the shunting effect of activity-dependent conductance on the generation of discharges. The obtained results suggest that the expression of CP-AMPARs in principal neurons reduces the discharge generation rate and may be considered as a protective mechanism.
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Affiliation(s)
- Dmitry V. Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Toreza Prospekt 44, 194223 Saint Petersburg, Russia; (D.V.A.); (E.B.S.); (A.V.C.)
| | - Elena B. Soboleva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Toreza Prospekt 44, 194223 Saint Petersburg, Russia; (D.V.A.); (E.B.S.); (A.V.C.)
| | - Anton V. Chizhov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Toreza Prospekt 44, 194223 Saint Petersburg, Russia; (D.V.A.); (E.B.S.); (A.V.C.)
- Ioffe Institute, Russian Academy of Sciences, Polytekhnicheskaya 26, 194021 Saint Petersburg, Russia
| | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Toreza Prospekt 44, 194223 Saint Petersburg, Russia; (D.V.A.); (E.B.S.); (A.V.C.)
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Sullivan BJ, Kipnis PA, Carter BM, Shao LR, Kadam SD. Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model. Sci Signal 2021; 14:eabg2648. [PMID: 34752143 DOI: 10.1126/scisignal.abg2648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Brennan J Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Brandon M Carter
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Li-Rong Shao
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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35
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Ergina JL, Amakhin DV, Postnikova TY, Soboleva EB, Zaitsev AV. Short-Term Epileptiform Activity Potentiates Excitatory Synapses but Does Not Affect Intrinsic Membrane Properties of Pyramidal Neurons in the Rat Hippocampus In Vitro. Biomedicines 2021; 9:biomedicines9101374. [PMID: 34680489 PMCID: PMC8533424 DOI: 10.3390/biomedicines9101374] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 12/19/2022] Open
Abstract
Even brief epileptic seizures can lead to activity-dependent structural remodeling of neural circuitry. Animal models show that the functional plasticity of synapses and changes in the intrinsic excitability of neurons can be crucial for epileptogenesis. However, the exact mechanisms underlying epileptogenesis remain unclear. We induced epileptiform activity in rat hippocampal slices for 15 min using a 4-aminopyridine (4-AP) in vitro model and observed hippocampal hyperexcitability for at least 1 h. We tested several possible mechanisms of this hyperexcitability, including changes in intrinsic membrane properties of neurons and presynaptic and postsynaptic alterations. Neither input resistance nor other essential biophysical properties of hippocampal CA1 pyramidal neurons were affected by epileptiform activity. The glutamate release probability also remained unchanged, as the frequency of miniature EPSCs and the paired amplitude ratio of evoked responses did not change after epileptiform activity. However, we found an increase in the AMPA/NMDA ratio, suggesting alterations in the properties of postsynaptic glutamatergic receptors. Thus, the increase in excitability of hippocampal neural networks is realized through postsynaptic mechanisms. In contrast, the intrinsic membrane properties of neurons and the probability of glutamate release from presynaptic terminals are not affected in a 4-AP model.
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Multimodal electrophysiological analyses reveal that reduced synaptic excitatory neurotransmission underlies seizures in a model of NMDAR antibody-mediated encephalitis. Commun Biol 2021; 4:1106. [PMID: 34545200 PMCID: PMC8452639 DOI: 10.1038/s42003-021-02635-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Seizures are a prominent feature in N-Methyl-D-Aspartate receptor antibody (NMDAR antibody) encephalitis, a distinct neuro-immunological disorder in which specific human autoantibodies bind and crosslink the surface of NMDAR proteins thereby causing internalization and a state of NMDAR hypofunction. To further understand ictogenesis in this disorder, and to test a potential treatment compound, we developed an NMDAR antibody mediated rat seizure model that displays spontaneous epileptiform activity in vivo and in vitro. Using a combination of electrophysiological and dynamic causal modelling techniques we show that, contrary to expectation, reduction of synaptic excitatory, but not inhibitory, neurotransmission underlies the ictal events through alterations in the dynamical behaviour of microcircuits in brain tissue. Moreover, in vitro application of a neurosteroid, pregnenolone sulphate, that upregulates NMDARs, reduced established ictal activity. This proof-of-concept study highlights the complexity of circuit disturbances that may lead to seizures and the potential use of receptor-specific treatments in antibody-mediated seizures and epilepsy.
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37
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Sheehan T, Amengual-Gual M, Vasquez A, Abend NS, Anderson A, Appavu B, Arya R, Barcia Aguilar C, Brenton JN, Carpenter JL, Chapman KE, Clark J, Farias-Moeller R, Gaillard WD, Gaínza-Lein M, Glauser TA, Goldstein JL, Goodkin HP, Guerriero RM, Huh L, Jackson M, Kapur K, Kahoud R, Lai YC, McDonough TL, Mikati MA, Morgan LA, Novotny EJ, Ostendorf AP, Payne ET, Peariso K, Piantino J, Reece L, Riviello JJ, Sands TT, Sannagowdara K, Shellhaas R, Smith G, Tasker RC, Tchapyjnikov D, Topjian AA, Wainwright MS, Wilfong A, Williams K, Zhang B, Loddenkemper T. Benzodiazepine administration patterns before escalation to second-line medications in pediatric refractory convulsive status epilepticus. Epilepsia 2021; 62:2766-2777. [PMID: 34418087 PMCID: PMC9292193 DOI: 10.1111/epi.17043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/21/2021] [Accepted: 08/05/2021] [Indexed: 11/30/2022]
Abstract
Objective This study was undertaken to evaluate benzodiazepine (BZD) administration patterns before transitioning to non‐BZD antiseizure medication (ASM) in pediatric patients with refractory convulsive status epilepticus (rSE). Methods This retrospective multicenter study in the United States and Canada used prospectively collected observational data from children admitted with rSE between 2011 and 2020. Outcome variables were the number of BZDs given before the first non‐BZD ASM, and the number of BZDs administered after 30 and 45 min from seizure onset and before escalating to non‐BZD ASM. Results We included 293 patients with a median (interquartile range) age of 3.8 (1.3–9.3) years. Thirty‐six percent received more than two BZDs before escalating, and the later the treatment initiation was after seizure onset, the less likely patients were to receive multiple BZD doses before transitioning (incidence rate ratio [IRR] = .998, 95% confidence interval [CI] = .997–.999 per minute, p = .01). Patients received BZDs beyond 30 and 45 min in 57.3% and 44.0% of cases, respectively. Patients with out‐of‐hospital seizure onset were more likely to receive more doses of BZDs beyond 30 min (IRR = 2.43, 95% CI = 1.73–3.46, p < .0001) and beyond 45 min (IRR = 3.75, 95% CI = 2.40–6.03, p < .0001) compared to patients with in‐hospital seizure onset. Intermittent SE was a risk factor for more BZDs administered beyond 45 min compared to continuous SE (IRR = 1.44, 95% CI = 1.01–2.06, p = .04). Forty‐seven percent of patients (n = 94) with out‐of‐hospital onset did not receive treatment before hospital arrival. Among patients with out‐of‐hospital onset who received at least two BZDs before hospital arrival (n = 54), 48.1% received additional BZDs at hospital arrival. Significance Failure to escalate from BZDs to non‐BZD ASMs occurs mainly in out‐of‐hospital rSE onset. Delays in the implementation of medical guidelines may be reduced by initiating treatment before hospital arrival and facilitating a transition to non‐BZD ASMs after two BZD doses during handoffs between prehospital and in‐hospital settings.
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Affiliation(s)
- Theodore Sheehan
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marta Amengual-Gual
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Pediatric Neurology Unit, Department of Pediatrics, Son Espases University Hospital, University of the Balearic Islands, Palma, Spain
| | - Alejandra Vasquez
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Nicholas S Abend
- Division of Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anne Anderson
- Section of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Brian Appavu
- Department of Pediatrics, University of Arizona College of Medicine and Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Ravindra Arya
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Cristina Barcia Aguilar
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Department of Child Neurology, La Paz University Hospital, Autonomous University of Madrid, Madrid, Spain
| | - J Nicholas Brenton
- Department of Neurology and Pediatrics, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jessica L Carpenter
- Center for Neuroscience, Children's National Medical Center, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Kevin E Chapman
- Departments of Pediatrics and Neurology, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Justice Clark
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Raquel Farias-Moeller
- Department of Neurology, Division of Pediatric Neurology, Children's Hospital of Wisconsin, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - William D Gaillard
- Center for Neuroscience, Children's National Medical Center, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Marina Gaínza-Lein
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Faculty of Medicine, Austral University of Chile, Valdivia, Chile
| | - Tracy A Glauser
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Joshua L Goldstein
- Ruth D. & Ken M. Davee Pediatric Neurocritical Care Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Howard P Goodkin
- Department of Neurology and Pediatrics, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Réjean M Guerriero
- Division of Pediatric and Developmental Neurology, Departments of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Linda Huh
- Division of Neurology, Department of Paediatrics, BC Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Michele Jackson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kush Kapur
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert Kahoud
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Mayo Clinic, Rochester, Minnesota, USA.,Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Yi-Chen Lai
- Section of Pediatric Critical Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Tiffani L McDonough
- Division of Child Neurology, Department of Neurology, Columbia University Medical Center, Columbia University, New York, New York, USA
| | - Mohamad A Mikati
- Division of Pediatric Neurology, Duke University Medical Center, Duke University, Durham, North Carolina, USA
| | - Lindsey A Morgan
- Departments of Neurology and Pediatrics, Division of Pediatric Neurology, University of Washington, Seattle Children's Hospital, Seattle, Washington, USA
| | - Edward J Novotny
- Departments of Neurology and Pediatrics, Division of Pediatric Neurology, University of Washington, Seattle Children's Hospital, Seattle, Washington, USA
| | - Adam P Ostendorf
- Department of Pediatrics, Nationwide Children's Hospital, Ohio State University, Columbus, Ohio, USA
| | - Eric T Payne
- Division of Neurology, Department of Pediatrics, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Katrina Peariso
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Juan Piantino
- Division of Neurology, Doernbecher Children's Hospital, Oregon Health & Science University, Portland, Oregon, USA
| | - Latania Reece
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - James J Riviello
- Section of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Tristan T Sands
- Division of Child Neurology, Department of Neurology, Columbia University Medical Center, Columbia University, New York, New York, USA
| | - Kumar Sannagowdara
- Department of Neurology, Division of Pediatric Neurology, Children's Hospital of Wisconsin, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Renee Shellhaas
- Department of Pediatrics, Division of Pediatric Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Garnett Smith
- Department of Pediatrics, Division of Pediatric Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert C Tasker
- Division of Critical Care, Departments of Neurology, Anesthesiology, and Perioperative and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Dmitry Tchapyjnikov
- Division of Pediatric Neurology, Duke University Medical Center, Duke University, Durham, North Carolina, USA.,Department of Pediatrics, Montana Children's Hospital, Kalispell Regional Medical Center, Kalispell, Montana, USA
| | - Alexis A Topjian
- Critical Care and Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Mark S Wainwright
- Departments of Neurology and Pediatrics, Division of Pediatric Neurology, University of Washington, Seattle Children's Hospital, Seattle, Washington, USA
| | - Angus Wilfong
- Department of Pediatrics, University of Arizona College of Medicine and Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Korwyn Williams
- Department of Pediatrics, University of Arizona College of Medicine and Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Bo Zhang
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tobias Loddenkemper
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Cannabidiol modifies the seizure expression and effects of antiseizure drugs in a rat model of recurrent severe seizures. Seizure 2021; 90:67-73. [DOI: 10.1016/j.seizure.2021.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/02/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
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39
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Zaitsev АV, Amakhin DV, Dyomina AV, Zakharova MV, Ergina JL, Postnikova TY, Diespirov GP, Magazanik LG. Synaptic Dysfunction in Epilepsy. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s002209302103008x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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40
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Kipnis PA, Kadam SD. Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures. Aging Dis 2021; 12:1056-1069. [PMID: 34221549 PMCID: PMC8219493 DOI: 10.14336/ad.2021.0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is associated with a multitude of acquired or genetic neurological disorders characterized by a predisposition to spontaneous recurrent seizures. An estimated 15 million patients worldwide have ongoing seizures despite optimal management and are classified as having refractory epilepsy. Early-life seizures like those caused by perinatal hypoxic ischemic encephalopathy (HIE) remain a clinical challenge because although transient, they are difficult to treat and associated with poor neurological outcomes. Pediatric epilepsy syndromes are consistently associated with intellectual disability and neurocognitive comorbidities. HIE and arterial ischemic stroke are the most common causes of seizures in term neonates and account for 7.5-20% of neonatal seizures. Standard first-line treatments such as phenobarbital (PB) and phenytoin fail to curb seizures in ~50% of neonates. In the long-term, HIE can result in hippocampal sclerosis and temporal lobe epilepsy (TLE), which is the most common adult epilepsy, ~30% of which is associated with refractory seizures. For patients with refractory TLE seizures, a viable option is the surgical resection of the epileptic foci. Novel insights gained from investigating the developmental role of Cl- cotransporter function have helped to elucidate some of the mechanisms underlying the emergence of refractory seizures in both HIE and TLE. KCC2 as the chief Cl- extruder in neurons is critical for enabling strong hyperpolarizing synaptic inhibition in the brain and has been implicated in the pathophysiology underlying both conditions. More recently, KCC2 function has become a novel therapeutic target to combat refractory seizures.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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41
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Rahmati N, Normoyle KP, Glykys J, Dzhala VI, Lillis KP, Kahle KT, Raiyyani R, Jacob T, Staley KJ. Unique Actions of GABA Arising from Cytoplasmic Chloride Microdomains. J Neurosci 2021; 41:4957-4975. [PMID: 33903223 PMCID: PMC8197632 DOI: 10.1523/jneurosci.3175-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/10/2021] [Accepted: 04/10/2021] [Indexed: 12/21/2022] Open
Abstract
Developmental, cellular, and subcellular variations in the direction of neuronal Cl- currents elicited by GABAA receptor activation have been frequently reported. We found a corresponding variance in the GABAA receptor reversal potential (EGABA) for synapses originating from individual interneurons onto a single pyramidal cell. These findings suggest a similar heterogeneity in the cytoplasmic intracellular concentration of chloride ([Cl-]i) in individual dendrites. We determined [Cl-]i in the murine hippocampus and cerebral cortex of both sexes by (1) two-photon imaging of the Cl--sensitive, ratiometric fluorescent protein SuperClomeleon; (2) Fluorescence Lifetime IMaging (FLIM) of the Cl--sensitive fluorophore MEQ (6-methoxy-N-ethylquinolinium); and (3) electrophysiological measurements of EGABA by pressure application of GABA and RuBi-GABA uncaging. Fluorometric and electrophysiological estimates of local [Cl-]i were highly correlated. [Cl-]i microdomains persisted after pharmacological inhibition of cation-chloride cotransporters, but were progressively modified after inhibiting the polymerization of the anionic biopolymer actin. These methods collectively demonstrated stable [Cl-]i microdomains in individual neurons in vitro and in vivo and the role of immobile anions in its stability. Our results highlight the existence of functionally significant neuronal Cl- microdomains that modify the impact of GABAergic inputs.SIGNIFICANCE STATEMENT Microdomains of varying chloride concentrations in the neuronal cytoplasm are a predictable consequence of the inhomogeneous distribution of anionic polymers such as actin, tubulin, and nucleic acids. Here, we demonstrate the existence and stability of these microdomains, as well as the consequence for GABAergic synaptic signaling: each interneuron produces a postsynaptic GABAA response with a unique reversal potential. In individual hippocampal pyramidal cells, the range of GABAA reversal potentials evoked by stimulating different interneurons was >20 mV. Some interneurons generated postsynaptic responses in pyramidal cells that reversed at potentials beyond what would be considered purely inhibitory. Cytoplasmic chloride microdomains enable each pyramidal cell to maintain a compendium of unique postsynaptic responses to the activity of individual interneurons.
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Affiliation(s)
- Negah Rahmati
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kieran P Normoyle
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Joseph Glykys
- Department of Pediatrics and Neurology, Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Volodymyr I Dzhala
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kyle P Lillis
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Rehan Raiyyani
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Theju Jacob
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kevin J Staley
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
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Khateb M, Bosak N, Herskovitz M. The Effect of Anti-seizure Medications on the Propagation of Epileptic Activity: A Review. Front Neurol 2021; 12:674182. [PMID: 34122318 PMCID: PMC8191738 DOI: 10.3389/fneur.2021.674182] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/09/2021] [Indexed: 11/13/2022] Open
Abstract
The propagation of epileptiform events is a highly interesting phenomenon from the pathophysiological point of view, as it involves several mechanisms of recruitment of neural networks. Extensive in vivo and in vitro research has been performed, suggesting that multiple networks as well as cellular candidate mechanisms govern this process, including the co-existence of wave propagation, coupled oscillator dynamics, and more. The clinical importance of seizure propagation stems mainly from the fact that the epileptic manifestations cannot be attributed solely to the activity in the seizure focus itself, but rather to the propagation of epileptic activity to other brain structures. Propagation, especially when causing secondary generalizations, poses a risk to patients due to recurrent falls, traumatic injuries, and poor neurological outcome. Anti-seizure medications (ASMs) affect propagation in diverse ways and with different potencies. Importantly, for drug-resistant patients, targeting seizure propagation may improve the quality of life even without a major reduction in simple focal events. Motivated by the extensive impact of this phenomenon, we sought to review the literature regarding the propagation of epileptic activity and specifically the effect of commonly used ASMs on it. Based on this body of knowledge, we propose a novel classification of ASMs into three main categories: major, minor, and intermediate efficacy in reducing the propagation of epileptiform activity.
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Affiliation(s)
- Mohamed Khateb
- Department of Neurology, Rambam Health Care Campus, Haifa, Israel
| | - Noam Bosak
- Department of Neurology, Rambam Health Care Campus, Haifa, Israel
| | - Moshe Herskovitz
- Department of Neurology, Rambam Health Care Campus, Haifa, Israel.,The Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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43
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Harrach MA, Benquet P, Wendling F. Long term evolution of fast ripples during epileptogenesis. J Neural Eng 2021; 18. [PMID: 33849005 DOI: 10.1088/1741-2552/abf774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/13/2021] [Indexed: 11/12/2022]
Abstract
Objective.Fast ripples (FRs) have received considerable attention in the last decade since they represent an electrophysiological biomarker of the epileptogenic zone (EZ). However, the real dynamics underlying the occurrence, amplitude, and time-frequency content of FRs generation during epileptogenesis are still not well understood. This work aims at characterizing and explaining the evolution of these features.Approach.Intracortical electroencephalographic signals recorded in a kainate mouse model of temporal lobe epilepsy were processed in order to compute specific FR features. Then realistic physiologically based computational modeling was employed to explore the different elements that can explain the mechanisms of epileptogenesis and simulate the recorded FR in the early and late latent period.Main results.Results indicated that continuous changes of FR features are mainly portrayed by the epileptic (pathological) tissue size and synaptic properties. Furthermore, the microelectrodes characteristics were found to dramatically affect the observability and spectral/temporal content of FRs. Consequently, FRs evolution seems to mirror the continuous pathophysiological mechanism changes that occur during epileptogenesis as long as the microelectrode properties are taken into account.Significance.Our study suggests that FRs can account for the pathophysiological changes which might explain the EZ generation and evolution and can contribute in the treatment plan of pharmaco-resistant epilepsies.
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Affiliation(s)
- Mariam Al Harrach
- Laboratoire Traitement du Signal et de l'Image (LTSI-U1099), Université de Rennes 1, INSERM, 35000 Rennes, France
| | - Pascal Benquet
- Laboratoire Traitement du Signal et de l'Image (LTSI-U1099), Université de Rennes 1, INSERM, 35000 Rennes, France
| | - Fabrice Wendling
- Laboratoire Traitement du Signal et de l'Image (LTSI-U1099), Université de Rennes 1, INSERM, 35000 Rennes, France
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Llauradó A, Quintana M, Ballvé A, Campos D, Fonseca E, Abraira L, Toledo M, Santamarina E. Factors associated with resistance to benzodiazepines in status epilepticus. J Neurol Sci 2021; 423:117368. [PMID: 33652289 DOI: 10.1016/j.jns.2021.117368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/18/2021] [Accepted: 02/20/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To investigate factors related to benzodiazepine (BZD) resistance in status epilepticus (SE) with a focus on their relationship with the etiology of the episode. METHODS All SE cases in patients aged >16 years treated with BZDs were prospectively collected in our center from February 2011 to April 2019. The registry included demographics, SE type and etiology, the timing and duration of BZD administration, and the outcome. In total, 371 episodes were analyzed. RESULTS Median age at SE onset was 61.3 years; the most frequent etiology was acute symptomatic (55.8%). SE with prominent motor symptoms occurred in 63.3%. Median time to BZD administration was 2 h. We studied the correlation between two-time variables: time from SE onset to BZD administration and time from BZD administration to resolution of SE (response); we observed that timely administration correlated with a faster response in patients with prominent motor symptoms (p = 0.017), SE due to a chronic structural cerebral lesion (p = 0.004), and patients with a history of seizures (p = 0.013). In these subgroups (prominent motor symptoms or chronic structural lesion) BZD administration within the first 4.5 h was highly associated with shorter post-BZD SE duration (p < 0.001). SIGNIFICANCE The relationship between prompt BZD administration and subsequent duration of SE was found to depend to some extent on the etiology of the episode: patients with chronic structural lesions and those with previous epilepsy responded faster to BZDs. Semiology may have also its impact, as the presence of prominent motor symptoms showed also a faster response.
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Affiliation(s)
- Arnau Llauradó
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Manuel Quintana
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Alejandro Ballvé
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Daniel Campos
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Elena Fonseca
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Laura Abraira
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Manuel Toledo
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain
| | - Estevo Santamarina
- Epilepsy Unit, Neurology Department, Vall de Hebron University Hospital, Barcelona, Spain.
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Dudek FE. Loss of GABAergic Interneurons in Seizure-Induced Epileptogenesis-Two Decades Later and in a More Complex World. Epilepsy Curr 2020; 20:70S-72S. [PMID: 33059465 PMCID: PMC7726724 DOI: 10.1177/1535759720960464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- F Edward Dudek
- Department of Neurosurgery 14434University of Utah School of Medicine, USA
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Breton VL, Dufour S, Chinvarun Y, Del Campo JM, Bardakjian BL, Carlen PL. Transitions between neocortical seizure and non-seizure-like states and their association with presynaptic glutamate release. Neurobiol Dis 2020; 146:105124. [PMID: 33010482 DOI: 10.1016/j.nbd.2020.105124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/16/2020] [Accepted: 09/28/2020] [Indexed: 11/28/2022] Open
Abstract
The transition between seizure and non-seizure states in neocortical epileptic networks is governed by distinct underlying dynamical processes. Based on the gamma distribution of seizure and inter-seizure durations, over time, seizures are highly likely to self-terminate; whereas, inter-seizure durations have a low chance of transitioning back into a seizure state. Yet, the chance of a state transition could be formed by multiple overlapping, unknown synaptic mechanisms. To identify the relationship between the underlying synaptic mechanisms and the chance of seizure-state transitions, we analyzed the skewed histograms of seizure durations in human intracranial EEG and seizure-like events (SLEs) in local field potential activity from mouse neocortical slices, using an objective method for seizure state classification. While seizures and SLE durations were demonstrated to have a unimodal distribution (gamma distribution shape parameter >1), suggesting a high likelihood of terminating, inter-SLE intervals were shown to have an asymptotic exponential distribution (gamma distribution shape parameter <1), suggesting lower probability of cessation. Then, to test cellular mechanisms for these distributions, we studied the modulation of synaptic neurotransmission during, and between, the in vitro SLEs. Using simultaneous local field potential and whole-cell voltage clamp recordings, we found a suppression of presynaptic glutamate release at SLE termination, as demonstrated by electrically- and optogenetically-evoked excitatory postsynaptic currents (EPSCs), and focal hypertonic sucrose application. Adenosine A1 receptor blockade interfered with the suppression of this release, changing the inter-SLE shape parameter from asymptotic exponential to unimodal, altering the chance of state transition occurrence with time. These findings reveal a critical role for presynaptic glutamate release in determining the chance of neocortical seizure state transitions.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Suzie Dufour
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; National Optics Institute, Biophotonics, Quebec, Canada G1P 4S4
| | - Yotin Chinvarun
- Comprehensive Epilepsy Program and Neurology Unit, Phramongkutklao Hospital, Bangkok, Thailand
| | - Jose Martin Del Campo
- Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Berj L Bardakjian
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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Huo J, Ren S, Gao P, Wan D, Rong S, Li X, Liu S, Xu S, Sun K, Guo B, Wang P, Yu B, Wu J, Wang F, Sun T. ALG13 participates in epileptogenesis via regulation of GABA A receptors in mouse models. Cell Death Discov 2020; 6:87. [PMID: 33014431 PMCID: PMC7499177 DOI: 10.1038/s41420-020-00319-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/09/2020] [Accepted: 09/01/2020] [Indexed: 12/23/2022] Open
Abstract
ALG13 (asparagine-linked glycosylation 13) plays crucial roles in the process of N-linked glycosylation. Mutations of the ALG13 gene underlie congenital disorders of glycosylation type I (CDG-I), a rare human genetic disorder with defective glycosylation. Epilepsy is commonly observed in congenital disorders of glycosylation type I (CDG-I). In our study, we found that about 20% of adult ALG13KO knockout mice display spontaneous seizures, which were identified in a simultaneous video and intracranial EEG recording. However, the mechanisms of ALG13 by which deficiency leads to epilepsy are unknown. Whole-cell patch-clamp recordings demonstrated that ALG13KO mice show a marked decrease in gamma-aminobutyric acid A receptor (GABAAR)-mediated inhibitory synaptic transmission. Furthermore, treatment with low-dose diazepam (a positive allosteric modulator of GABAA receptors), which enhances GABAAR function, also markedly ameliorates severity of epileptic seizures in ALG13KO mice. Moreover, ALG13 may influenced the expression of GABAARα2 membrane and total protein by changing transcription level of GABAARα2. Furthermore, protein interactions between ALG13 and GABAARα2 were observed in the cortex of wild-type mice. Overall, these results reveal that ALG13 may be involved in the occurrence of epilepsy through the regulation of GABAAR function, and may provide new insight into epilepsy prevention and treatment.
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Affiliation(s)
- Junming Huo
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Shuanglai Ren
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Peng Gao
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, 804 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Ding Wan
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, 804 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Shikuo Rong
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Xinxiao Li
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Shenhai Liu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Siying Xu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Kuisheng Sun
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Baorui Guo
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Peng Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Baoli Yu
- Renji Hospital Shanghai Jiaotong University School of Medicine, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Ji Wu
- Renji Hospital Shanghai Jiaotong University School of Medicine, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200240 China
- Ningxia Key Laboratory of Reproduction and Genetics, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, 804 Shengli Street, Yinchuan, 750001 Ningxia China
| | - Tao Sun
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001 Ningxia China
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Akita T, Fukuda A. Intracellular Cl - dysregulation causing and caused by pathogenic neuronal activity. Pflugers Arch 2020; 472:977-987. [PMID: 32300887 DOI: 10.1007/s00424-020-02375-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/23/2020] [Accepted: 03/27/2020] [Indexed: 02/06/2023]
Abstract
The intracellular Cl- concentration ([Cl-]i) is tightly regulated in brain neurons for stabilizing brain performance. The [Cl-]i in mature neurons is determined by the balance between the rate of Cl- extrusion mainly mediated by the neuron-specific type 2 K+-Cl- cotransporter (KCC2) and the rate of Cl- entry through various Cl- channels including GABAA receptors during neuronal activity. Disturbance of the balance causes instability of brain circuit performance and may lead to epileptic seizures. In the first part of this review, we discuss how genetic alterations in KCC2 in humans cause infantile migrating focal seizures, based on our previous report and others. Depolarization of the membrane potential increases the driving force for Cl- entry into neurons. Thus, the duration of action potential spike generation and the frequency of excitatory synaptic inputs are the crucial factors for determining the total amount of Cl- entry and the equilibrium [Cl-]i in neurons. Moreover, there is also a significant interdependence between the neuronal activity and the KCC2 expression. In the second part, we discuss plausible mechanisms by which excessive neuronal activity due to excitotoxic brain insults or other epilepsy-associated gene mutations may cause the Cl- imbalance in neurons and lead to epileptic discharges over the brain, using the schematic "unifying foci" model based on literature.
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Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan.
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
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The adenosine A1 receptor agonist WAG 994 suppresses acute kainic acid-induced status epilepticus in vivo. Neuropharmacology 2020; 176:108213. [PMID: 32615188 DOI: 10.1016/j.neuropharm.2020.108213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/22/2022]
Abstract
Status epilepticus (SE) is a neurological emergency characterized by continuous seizure activity lasting longer than 5 min, often with no recovery between seizures (Trinka et al., 2015). SE is refractory to benzodiazepine and second-line treatments in about 30% cases. Novel treatment approaches are urgently needed as refractory SE is associated with mortality rates of up to 70%. Robust adenosinergic anticonvulsant effects have been known for decades, but translation into seizure treatments was hampered by cardiovascular side effects. However, the selective adenosine A1 receptor agonist SDZ WAG 994 (WAG) displays diminished cardiovascular side effects compared to classic A1R agonists and was safely administered systemically in human clinical trials. Here, we investigate the anticonvulsant efficacy of WAG in vitro and in vivo. WAG robustly inhibited high-K+-induced continuous epileptiform activity in rat hippocampal slices (IC50 = 52.5 nM). Importantly, WAG acutely suppressed SE in vivo induced by kainic acid (20 mg/kg i.p.) in mice. After SE was established, mice received three i.p. injections of WAG or diazepam (DIA, 5 mg/kg). Interestingly, DIA did not attenuate SE while the majority of WAG-treated mice (1 mg/kg) were seizure-free after three injections. Anticonvulsant effects were retained when a lower dose of WAG (0.3 mg/kg) was used. Importantly, all WAG-treated mice survived kainic acid induced SE. In summary, we report for the first time that an A1R agonist with an acceptable human side-effect profile can acutely suppress established SE in vivo. Our results suggest that WAG stops or vastly attenuates SE while DIA fails to mitigate SE in this model.
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50
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Currin CB, Trevelyan AJ, Akerman CJ, Raimondo JV. Chloride dynamics alter the input-output properties of neurons. PLoS Comput Biol 2020; 16:e1007932. [PMID: 32453795 PMCID: PMC7307785 DOI: 10.1371/journal.pcbi.1007932] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 06/22/2020] [Accepted: 05/06/2020] [Indexed: 12/30/2022] Open
Abstract
Fast synaptic inhibition is a critical determinant of neuronal output, with subcellular targeting of synaptic inhibition able to exert different transformations of the neuronal input-output function. At the receptor level, synaptic inhibition is primarily mediated by chloride-permeable Type A GABA receptors. Consequently, dynamics in the neuronal chloride concentration can alter the functional properties of inhibitory synapses. How differences in the spatial targeting of inhibitory synapses interact with intracellular chloride dynamics to modulate the input-output function of neurons is not well understood. To address this, we developed computational models of multi-compartment neurons that incorporate experimentally parametrised mechanisms to account for neuronal chloride influx, diffusion, and extrusion. We found that synaptic input (either excitatory, inhibitory, or both) can lead to subcellular variations in chloride concentration, despite a uniform distribution of chloride extrusion mechanisms. Accounting for chloride changes resulted in substantial alterations in the neuronal input-output function. This was particularly the case for peripherally targeted dendritic inhibition where dynamic chloride compromised the ability of inhibition to offset neuronal input-output curves. Our simulations revealed that progressive changes in chloride concentration mean that the neuronal input-output function is not static but varies significantly as a function of the duration of synaptic drive. Finally, we found that the observed effects of dynamic chloride on neuronal output were mediated by changes in the dendritic reversal potential for GABA. Our findings provide a framework for understanding the computational effects of chloride dynamics on dendritically targeted synaptic inhibition.
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Affiliation(s)
- Christopher B. Currin
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Andrew J. Trevelyan
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Colin J. Akerman
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Joseph V. Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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