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Jia R, Zhu G, Zhao R, Li T, Jiang W, Cui X. Hydrogen treatment reduces electroencephalographic activity and neuronal death in rats with refractory status epilepticus by inhibiting membrane NR2B phosphorylation and oxidative stress. J Int Med Res 2024; 52:3000605241235589. [PMID: 38546233 PMCID: PMC10981235 DOI: 10.1177/03000605241235589] [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: 09/25/2023] [Accepted: 02/09/2024] [Indexed: 04/01/2024] Open
Abstract
OBJECTIVE To investigate the effects of hydrogen therapy on epileptic seizures in rats with refractory status epilepticus and the underlying mechanisms. METHODS Status epilepticus was induced using pilocarpine. The effects of hydrogen treatment on epilepsy severity in model rats were then monitored using Racine scores and electroencephalography (EEG), followed by western blot of plasma membrane N-methyl-D-aspartate receptor subtype 2B (NR2B) and phosphorylated NR2B expression. We also generated a cellular epilepsy model using Mg2+-free medium and used polymerase chain reaction to investigate the neuroprotective effects of hydrogen. RESULTS There were no significant differences in Racine scores between the hydrogen and control groups. EEG amplitudes were lower in the hydrogen treatment group than in the control group. In epilepsy model rats, hippocampal cell membrane NR2B expression and phosphorylation increased gradually over time. Although hippocampal cell membrane NR2B expression was not significantly different between the two groups, NR2B phosphorylation levels were significantly lower in the hydrogen group. Hydrogen treatment also increased superoxide dismutase, mitochondrial (SOD2) expression. CONCLUSIONS Hydrogen treatment reduced EEG amplitudes and NR2B phosphorylation; it also decreased neuronal death by reducing oxidative stress. Hydrogen may thus be a potential treatment for refractory status epilepticus by inhibiting membrane NR2B phosphorylation and oxidative stress.
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Affiliation(s)
- Ruihua Jia
- Department of Neurology, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Gemin Zhu
- Department of Neurology, Xi’an Central Hospital, Xi’an, China
| | - Rui Zhao
- Department of Neurology, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Tian Li
- School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Wen Jiang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Xiaoli Cui
- Department of Neurology, Shaanxi Provincial People’s Hospital, Xi’an, China
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2
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Song C, Zhao J, Hao J, Mi D, Zhang J, Liu Y, Wu S, Gao F, Jiang W. Aminoprocalcitonin protects against hippocampal neuronal death via preserving oxidative phosphorylation in refractory status epilepticus. Cell Death Discov 2023; 9:144. [PMID: 37142587 PMCID: PMC10160063 DOI: 10.1038/s41420-023-01445-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/06/2023] Open
Abstract
Refractory status epilepticus (RSE) is a neurological emergency where sustaining seizure causes severe neuronal death. Currently, there is no available neuroprotectant effective in RSE. Aminoprocalcitonin (NPCT) is a conserved peptide cleaved from procalcitonin, but its distribution and function in the brain remain enigmatic. Survival of neurons relies on sufficient energy supply. Recently, we found that NPCT was extensively distributed in the brain and had potent modulations on neuronal oxidative phosphorylation (OXPHOS), suggesting that NPCT might be involved in neuronal death by regulating energy status. In the present study, combining biochemical and histological methods, high-throughput RNA-sequence, Seahorse XFe analyser, an array of mitochondria function assays, and behavior-electroencephalogram (EEG) monitoring, we investigated the roles and translational values of NPCT in neuronal death after RSE. We found that NPCT was extensively distributed throughout gray matters in rat brain while RSE triggered NPCT overexpression in hippocampal CA3 pyramidal neurons. High-throughput RNA-sequence demonstrated that the influences of NPCT on primary hippocampal neurons were enriched in OXPHOS. Further function assays verified that NPCT facilitated ATP production, enhanced the activities of mitochondrial respiratory chain complexes I, IV, V, and increased neuronal maximal respiration capacity. NPCT exerted multiple neurotrophic effects including facilitating synaptogenesis, neuritogenesis, spinogenesis, and suppression of caspase-3. A polyclonal NPCT immunoneutralization antibody was developed to antagonize NPCT. In the in vitro 0-Mg2+ seizure model, immunoneutralization of NPCT caused more neuronal death, while exogenous NPCT supplementation, though did not reverse death outcomes, preserved mitochondrial membrane potential. In rat RSE model, both peripheral and intracerebroventricular immunoneutralization of NPCT exacerbated hippocampal neuronal death and peripheral immunoneutralization increased mortality. Intracerebroventricular immunoneutralization of NPCT further led to more serious hippocampal ATP depletion, and significant EEG power exhaustion. We conclude that NPCT is a neuropeptide regulating neuronal OXPHOS. During RSE, NPCT was overexpressed to protect hippocampal neuronal survival via facilitating energy supply.
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Affiliation(s)
- Changgeng Song
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jingjing Zhao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jianmin Hao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Dan Mi
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jiajia Zhang
- National Translational Science Centre for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Yingying Liu
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Shengxi Wu
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Fang Gao
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China.
| | - Wen Jiang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China.
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3
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Naylor DE. In the fast lane: Receptor trafficking during status epilepticus. Epilepsia Open 2023; 8 Suppl 1:S35-S65. [PMID: 36861477 PMCID: PMC10173858 DOI: 10.1002/epi4.12718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Status epilepticus (SE) remains a significant cause of morbidity and mortality and often is refractory to standard first-line treatments. A rapid loss of synaptic inhibition and development of pharmacoresistance to benzodiazepines (BZDs) occurs early during SE, while NMDA and AMPA receptor antagonists remain effective treatments after BZDs have failed. Multimodal and subunit-selective receptor trafficking within minutes to an hour of SE involves GABA-A, NMDA, and AMPA receptors and contributes to shifts in the number and subunit composition of surface receptors with differential impacts on the physiology, pharmacology, and strength of GABAergic and glutamatergic currents at synaptic and extrasynaptic sites. During the first hour of SE, synaptic GABA-A receptors containing γ2 subunits move to the cell interior while extrasynaptic GABA-A receptors with δ subunits are preserved. Conversely, NMDA receptors containing N2B subunits are increased at synaptic and extrasynaptic sites, and homomeric GluA1 ("GluA2-lacking") calcium permeant AMPA receptor surface expression also is increased. Molecular mechanisms, largely driven by NMDA receptor or calcium permeant AMPA receptor activation early during circuit hyperactivity, regulate subunit-specific interactions with proteins involved with synaptic scaffolding, adaptin-AP2/clathrin-dependent endocytosis, endoplasmic reticulum (ER) retention, and endosomal recycling. Reviewed here is how SE-induced shifts in receptor subunit composition and surface representation increase the excitatory to inhibitory imbalance that sustains seizures and fuels excitotoxicity contributing to chronic sequela such as "spontaneous recurrent seizures" (SRS). A role for early multimodal therapy is suggested both for treatment of SE and for prevention of long-term comorbidities.
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Affiliation(s)
- David E Naylor
- VA Greater Los Angeles Healthcare System, Department of Neurology, David Geffen School of Medicine at UCLA, and The Lundquist Institute at Harbor-UCLA Medical Center, Los Angeles, California, USA
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4
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Tipton AE, Russek SJ. Regulation of Inhibitory Signaling at the Receptor and Cellular Level; Advances in Our Understanding of GABAergic Neurotransmission and the Mechanisms by Which It Is Disrupted in Epilepsy. Front Synaptic Neurosci 2022; 14:914374. [PMID: 35874848 PMCID: PMC9302637 DOI: 10.3389/fnsyn.2022.914374] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Inhibitory signaling in the brain organizes the neural circuits that orchestrate how living creatures interact with the world around them and how they build representations of objects and ideas. Without tight control at multiple points of cellular engagement, the brain’s inhibitory systems would run down and the ability to extract meaningful information from excitatory events would be lost leaving behind a system vulnerable to seizures and to cognitive decline. In this review, we will cover many of the salient features that have emerged regarding the dynamic regulation of inhibitory signaling seen through the lens of cell biology with an emphasis on the major building blocks, the ligand-gated ion channel receptors that are the first transduction point when the neurotransmitter GABA is released into the synapse. Epilepsy association will be used to indicate importance of key proteins and their pathways to brain function and to introduce novel areas for therapeutic intervention.
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Affiliation(s)
- Allison E. Tipton
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Biomolecular Pharmacology Program, Boston University School of Medicine, Boston, MA, United States
- Boston University MD/PhD Training Program, Boston, MA, United States
| | - Shelley J. Russek
- Biomolecular Pharmacology Program, Boston University School of Medicine, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Boston University MD/PhD Training Program, Boston, MA, United States
- *Correspondence: Shelley J. Russek,
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5
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Abstract
Drug-resistant epilepsy is associated with poor health outcomes and increased economic burden. In the last three decades, various new antiseizure medications have been developed, but the proportion of people with drug-resistant epilepsy remains relatively unchanged. Developing strategies to address drug-resistant epilepsy is essential. Here, we define drug-resistant epilepsy and emphasize its relationship to the conceptualization of epilepsy as a symptom complex, delineate clinical risk factors, and characterize mechanisms based on current knowledge. We address the importance of ruling out pseudoresistance and consider the impact of nonadherence on determining whether an individual has drug-resistant epilepsy. We then review the principles of epilepsy drug therapy and briefly touch upon newly approved and experimental antiseizure medications.
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6
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Defining and overcoming the therapeutic obstacles in canine refractory status epilepticus. Vet J 2022; 283-284:105828. [DOI: 10.1016/j.tvjl.2022.105828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 11/20/2022]
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7
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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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8
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Hong GP, Kim MH, Kim HJ. Sex-related Differences in Glial Fibrillary Acidic Protein-positive GABA Regulate Neuropathology Following Pilocarpine-induced Status Epilepticus. Neuroscience 2021; 472:157-166. [PMID: 34400247 DOI: 10.1016/j.neuroscience.2021.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 12/31/2022]
Abstract
Status epilepticus (SE) is a life-threatening neurological disorder that causes neuronal death and glial activation. Studies have explained the clinical side effects and lack of effectiveness of neurological disorder treatments based on sex-related differences in brain structure and function. However, the sex-specific outcomes of seizure disorders and the underlying mechanisms remain unknown. We compared SE-induced behavioral and pathophysiological changes in male and female mice. The time taken to reach stage 6 seizure following pilocarpine injection was shorter in male mice than in female mice, and the prevalence of SE was higher in male mice than in female mice. Fluoro-Jade B staining revealed more extensive SE-induced hippocampal neuronal death in male mice than in female mice. Glial cells were more activated in male mice than in female mice. In contrast, astrocyte-derived γ-aminobutyric acid (GABA)-immunostaining was less expressed in male mice than in female mice. Moreover, the mRNA levels of inflammatory cytokines released from activated glial cells were higher in male mice than in female mice. Notably, the mRNA level of astrocytic γ-aminobutyric acid transporter (GAT-3) involved in extracellular GABA uptake was lower in female mice than in male mice, while the mRNA levels of glutamate/aspartate transporter (GLAST (EAAT1)) and glutamate transporter (GLT-1 (EAAT2)) involved in extracellular glutamate uptake were higher in female mice. Our findings suggest that male mice are more vulnerable to SE than female mice, resulting in more extensive neuronal cell death and glial activation in male mice, partly due to increased GAT-3 expression that subsequently leads to reduced glial fibrillary acidic protein (GFAP)-positive GABA content assessed with anti-GABA antibodies.
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Affiliation(s)
- Geum Pyo Hong
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Mi-Hye Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea.
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9
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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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10
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Charalambous M, Volk HA, Van Ham L, Bhatti SFM. First-line management of canine status epilepticus at home and in hospital-opportunities and limitations of the various administration routes of benzodiazepines. BMC Vet Res 2021; 17:103. [PMID: 33663513 PMCID: PMC7934266 DOI: 10.1186/s12917-021-02805-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/16/2021] [Indexed: 12/22/2022] Open
Affiliation(s)
- Marios Charalambous
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
| | - Holger A Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Luc Van Ham
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium
| | - Sofie F M Bhatti
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium
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11
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Kim P, Scott MR, Meador-Woodruff JH. Dysregulation of the unfolded protein response (UPR) in the dorsolateral prefrontal cortex in elderly patients with schizophrenia. Mol Psychiatry 2021; 26:1321-1331. [PMID: 31578497 PMCID: PMC7113111 DOI: 10.1038/s41380-019-0537-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 09/10/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022]
Abstract
Abnormalities in protein localization, function, and posttranslational modifications are targets of schizophrenia (SCZ) research. As a major contributor to the synthesis, folding, trafficking, and modification of proteins, the endoplasmic reticulum (ER) is well-positioned to sense cellular stress. The unfolded protein response (UPR) is an evolutionarily conserved adaptive reaction to environmental and pathological perturbation in ER function. The UPR is a highly orchestrated and complex cellular response, which is mediated through the ER chaperone protein, BiP, three known ER transmembrane stress sensors, protein kinase RNA-like ER kinase (PERK), activating transcription factor-6 (ATF6), inositol requiring enzyme 1α (IRE1α), and their downstream effectors. In this study, we measured protein expression and phosphorylation states of UPR sensor pathway proteins in the dorsolateral prefrontal cortex (DLPFC) of 22 matched pairs of elderly SCZ and comparison subjects. We observed increased protein expression of BiP, decreased PERK, and decreased phosphorylation of IRE1α. We also observed decreased p-JNK2 and increased sXBP1, downstream targets of the IRE1α arm of the UPR. The disconnect between decreased p-IRE1α and increased sXBP1 protein expression led us to measure sXbp1 mRNA. We observed increased expression of the ratio of sXbp1/uXbp1 transcripts, suggesting that splicing of Xbp1 mRNA by IRE1α is increased and drives upregulation of sXBP1 protein expression. These findings suggest an abnormal pattern of UPR activity in SCZ, with specific dysregulation of the IRE1α arm. Dysfunction of this system may lead to abnormal responses to cellular stressors and contribute to protein processing abnormalities previously observed in SCZ.
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Affiliation(s)
- Pitna Kim
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Madeline R. Scott
- grid.265892.20000000106344187Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - James H. Meador-Woodruff
- grid.265892.20000000106344187Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
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12
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Juvale IIA, Che Has AT. Possible interplay between the theories of pharmacoresistant epilepsy. Eur J Neurosci 2020; 53:1998-2026. [PMID: 33306252 DOI: 10.1111/ejn.15079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/22/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
Epilepsy is one of the oldest known neurological disorders and is characterized by recurrent seizure activity. It has a high incidence rate, affecting a broad demographic in both developed and developing countries. Comorbid conditions are frequent in patients with epilepsy and have detrimental effects on their quality of life. Current management options for epilepsy include the use of anti-epileptic drugs, surgery, or a ketogenic diet. However, more than 30% of patients diagnosed with epilepsy exhibit drug resistance to anti-epileptic drugs. Further, surgery and ketogenic diets do little to alleviate the symptoms of patients with pharmacoresistant epilepsy. Thus, there is an urgent need to understand the underlying mechanisms of pharmacoresistant epilepsy to design newer and more effective anti-epileptic drugs. Several theories of pharmacoresistant epilepsy have been suggested over the years, the most common being the gene variant hypothesis, network hypothesis, multidrug transporter hypothesis, and target hypothesis. In our review, we discuss the main theories of pharmacoresistant epilepsy and highlight a possible interconnection between their mechanisms that could lead to the development of novel therapies for pharmacoresistant epilepsy.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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13
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Straub J, Gawda A, Ravichandran P, McGrew B, Nylund E, Kang J, Burke C, Vitko I, Scott M, Williamson J, Joshi S, Kapur J, Perez-Reyes E. Characterization of kindled VGAT-Cre mice as a new animal model of temporal lobe epilepsy. Epilepsia 2020; 61:2277-2288. [PMID: 32954490 DOI: 10.1111/epi.16651] [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: 06/06/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Development of novel therapies for temporal lobe epilepsy is hindered by a lack of models suitable for drug screening. While testing the hypothesis that "inhibiting inhibitory neurons" was sufficient to induce seizures, it was discovered that a mild electrical kindling protocol of VGAT-Cre mice led to spontaneous motor and electrographic seizures. This study characterizes these seizures and investigates the mechanism. METHODS Mice were implanted with electroencephalographic (EEG) headsets that included a stimulating electrode in the hippocampus before being electrically kindled. Seizures were evaluated by review of EEG recordings and behavior. γ-Aminobutyric acidergic (GABAergic) neurotransmission was evaluated by quantitative polymerase chain reaction, immunocytochemistry, Western blot, and electrophysiology. RESULTS Electrical kindling of VGAT-Cre mice induces spontaneous recurring seizures after a short latency (6 days). Seizures occur 1-2 times per day in both male and female mice, with only minimal neuronal death. These mice express Cre recombinase under the control of the vesicular GABA transporter (VGAT), a gene that is specifically expressed in GABAergic inhibitory neurons. The insertion of Cre disrupts the expression of VGAT mRNA and protein, and impairs GABAergic synaptic transmission in the hippocampus. SIGNIFICANCE Kindled VGAT-Cre mice can be used to study the mechanisms involved in epileptogenesis and may be useful for screening novel therapeutics.
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Affiliation(s)
- Justyna Straub
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Agnieszka Gawda
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Pranav Ravichandran
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Bailey McGrew
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Elsa Nylund
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Julianna Kang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Cassidy Burke
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Iuliia Vitko
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Michael Scott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - John Williamson
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA.,UVA Brain Institute, University of Virginia, Charlottesville, Virginia, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA.,UVA Brain Institute, University of Virginia, Charlottesville, Virginia, USA
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14
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Adotevi N, Lewczuk E, Sun H, Joshi S, Dabrowska N, Shan S, Williamson J, Kapur J. α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid Receptor Plasticity Sustains Severe, Fatal Status Epilepticus. Ann Neurol 2019; 87:84-96. [PMID: 31675128 DOI: 10.1002/ana.25635] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Generalized convulsive status epilepticus is associated with high mortality. We tested whether α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor plasticity plays a role in sustaining seizures, seizure generalization, and mortality observed during focal onset status epilepticus. We also determined whether modified AMPA receptors generated during status epilepticus could be targeted with a drug. METHODS Electrically induced status epilepticus was characterized by electroencephalogram and behavior in GluA1 knockout mice and in transgenic mice with selective knockdown of the GluA1 subunit in hippocampal principal neurons. Excitatory and inhibitory synaptic transmission in CA1 neurons was studied using patch clamp electrophysiology. The dose response of N,N,H,-trimethyl-5-([tricyclo(3.3.1.13,7)dec-1-ylmethyl]amino)-1-pentanaminiumbromide hydrobromide (IEM-1460), a calcium-permeable AMPA receptor antagonist, was determined. RESULTS Global removal of the GluA1 subunit did not affect seizure susceptibility; however, it reduced susceptibility to status epilepticus. GluA1 subunit knockout also reduced mortality, severity, and duration of status epilepticus. Absence of the GluA1 subunit prevented enhancement of glutamatergic synaptic transmission associated with status epilepticus; however, γ-aminobutyric acidergic synaptic inhibition was compromised. Selective removal of the GluA1 subunit from hippocampal principal neurons also reduced mortality, severity, and duration of status epilepticus. IEM-1460 rapidly terminated status epilepticus in a dose-dependent manner. INTERPRETATION AMPA receptor plasticity mediated by the GluA1 subunit plays a critical role in sustaining and amplifying seizure activity and contributes to mortality. Calcium-permeable AMPA receptors modified during status epilepticus can be inhibited to terminate status epilepticus. ANN NEUROL 2020;87:84-96.
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Affiliation(s)
- Nadia Adotevi
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Ewa Lewczuk
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Huayu Sun
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Natalia Dabrowska
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Sarah Shan
- College of Arts and Sciences, University of Virginia, Charlottesville, VA
| | - John Williamson
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA.,UVA Brain Institute, University of Virginia, Charlottesville, VA
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15
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Gaínza-Lein M, Fernández IS, Ulate-Campos A, Loddenkemper T, Ostendorf AP. Timing in the treatment of status epilepticus: From basics to the clinic. Seizure 2019; 68:22-30. [DOI: 10.1016/j.seizure.2018.05.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/18/2018] [Accepted: 05/29/2018] [Indexed: 02/07/2023] Open
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Ríos C, Farfán-Briseño AC, Manjarrez-Marmolejo J, Franco-Pérez J, Méndez-Armenta M, Nava-Ruiz C, Caballero-Chacón S, Ruiz-Diaz A, Baron-Flores V, Díaz-Ruiz A. Efficacy of dapsone administered alone or in combination with diazepam to inhibit status epilepticus in rats. Brain Res 2019; 1708:181-187. [DOI: 10.1016/j.brainres.2018.12.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/13/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
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17
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Kapur J. Role of NMDA receptors in the pathophysiology and treatment of status epilepticus. Epilepsia Open 2018; 3:165-168. [PMID: 30564775 PMCID: PMC6293062 DOI: 10.1002/epi4.12270] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 12/23/2022] Open
Abstract
This review considers the role of N-methyl-d-aspartate receptors in the pathophysiology and treatment of status epilepticus (SE). NMDA receptors play a critical role in sustaining SE by mediating the plasticity of γ-aminobutyric acid (GABA)-A and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, neuronal loss, and epileptogenesis. In parallel, there is growing interest in using the NMDA receptor antagonist ketamine in the treatment of refractory SE. Ketamine has proved to be safe for use in refractory and super-refractory SE in patients. The pilot studies also suggest that ketamine may be efficacious for termination of refractory SE.
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Affiliation(s)
- Jaideep Kapur
- Department of Neurology Department of Neuroscience, Brain Institute University of Virginia Charlottesville Virginia U.S.A
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18
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Lorenz-Guertin JM, Bambino MJ, Jacob TC. γ2 GABA AR Trafficking and the Consequences of Human Genetic Variation. Front Cell Neurosci 2018; 12:265. [PMID: 30190672 PMCID: PMC6116786 DOI: 10.3389/fncel.2018.00265] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/02/2018] [Indexed: 11/13/2022] Open
Abstract
GABA type A receptors (GABAARs) mediate the majority of fast inhibitory neurotransmission in the central nervous system (CNS). Most prevalent as heteropentamers composed of two α, two β, and a γ2 subunit, these ligand-gated ionotropic chloride channels are capable of extensive genetic diversity (α1-6, β1-3, γ1-3, δ, 𝜀, 𝜃, π, ρ1-3). Part of this selective GABAAR assembly arises from the critical role for γ2 in maintaining synaptic receptor localization and function. Accordingly, mutations in this subunit account for over half of the known epilepsy-associated genetic anomalies identified in GABAARs. Fundamental structure-function studies and cellular pathology investigations have revealed dynamic GABAAR trafficking and synaptic scaffolding as critical regulators of GABAergic inhibition. Here, we introduce in vitro and in vivo findings regarding the specific role of the γ2 subunit in receptor trafficking. We then examine γ2 subunit human genetic variation and assess disease related phenotypes and the potential role of altered GABAAR trafficking. Finally, we discuss new-age imaging techniques and their potential to provide novel insight into critical regulatory mechanisms of GABAAR function.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew J Bambino
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Joshi S, Rajasekaran K, Hawk KM, Chester SJ, Goodkin HP. Status epilepticus: Role for etiology in determining response to benzodiazepines. Ann Neurol 2018; 83:830-841. [PMID: 29572918 DOI: 10.1002/ana.25213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Clinical factors contributing to benzodiazepine failure in treating status epilepticus (SE) include suboptimal dosing and seizure duration. As many benzodiazepine-refractory episodes of SE arise from acute etiologies, we sought to determine whether etiology impacts SE treatment. METHODS The potency of diazepam to terminate SE induced by lithium-pilocarpine (LiPilo-SE) or kainic acid (KA-SE) in 3-week-old rats was studied by video-electroencephalography. Synaptic γ-aminobutyric acid type A receptor (GABAR)-mediated currents were recorded from dentate granule cells using voltage-clamp electrophysiology. Surface expression of γ2 subunit-containing GABARs and Kv4.2 potassium channels in hippocampal slices was determined using a biotinylation assay. Expression of phosphorylated forms of β2/3 and γ2 subunits was determined using phosphospecific antibodies and Western blotting. RESULTS Diazepam failed to terminate late SE in LiPilo-SE animals but was successful in terminating KA-SE of 1- and 3-hour duration. One hour after SE onset, GABAR-mediated synaptic inhibition and γ2 subunit-containing GABAR surface expression were reduced in LiPilo-SE animals. These were unchanged in KA-SE animals at 1 and 3 hours. Phosphorylation of γ2 subunit residue S327 was unchanged in both models, although GABAR β3 subunit S408/409 residues were dephosphorylated in the LiPilo-SE animals. Kv4.2 potassium channel surface expression was increased in LiPilo-SE animals but reduced in KA-SE animals. INTERPRETATION SE-model-dependent differences support a novel hypothesis that the development of benzodiazepine pharmacoresistance may be etiologically predetermined. Further studies are required to investigate the mechanisms that underlie such etiological differences during SE and whether etiology-dependent protocols for the treatment of SE need to be developed. Ann Neurol 2018;83:830-841.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, VA
| | | | - Kyle M Hawk
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Stephen J Chester
- Department of Neurology, University of Virginia, Charlottesville, VA
| | - Howard P Goodkin
- Department of Pediatrics, University of Virginia, Charlottesville, VA
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20
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Lorenz-Guertin JM, Jacob TC. GABA type a receptor trafficking and the architecture of synaptic inhibition. Dev Neurobiol 2018; 78:238-270. [PMID: 28901728 PMCID: PMC6589839 DOI: 10.1002/dneu.22536] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022]
Abstract
Ubiquitous expression of GABA type A receptors (GABAA R) in the central nervous system establishes their central role in coordinating most aspects of neural function and development. Dysregulation of GABAergic neurotransmission manifests in a number of human health disorders and conditions that in certain cases can be alleviated by drugs targeting these receptors. Precise changes in the quantity or activity of GABAA Rs localized at the cell surface and at GABAergic postsynaptic sites directly impact the strength of inhibition. The molecular mechanisms constituting receptor trafficking to and from these compartments therefore dictate the efficacy of GABAA R function. Here we review the current understanding of how GABAA Rs traffic through biogenesis, plasma membrane transport, and degradation. Emphasis is placed on discussing novel GABAergic synaptic proteins, receptor and scaffolding post-translational modifications, activity-dependent changes in GABAA R confinement, and neuropeptide and neurosteroid mediated changes. We further highlight modern techniques currently advancing the knowledge of GABAA R trafficking and clinically relevant neurodevelopmental diseases connected to GABAergic dysfunction. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 238-270, 2018.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15261
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15261
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21
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Pilocarpine-Induced Status Epilepticus Is Associated with Changes in the Actin-Modulating Protein Synaptopodin and Alterations in Long-Term Potentiation in the Mouse Hippocampus. Neural Plast 2017; 2017:2652560. [PMID: 28154762 PMCID: PMC5244022 DOI: 10.1155/2017/2652560] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 12/28/2022] Open
Abstract
Epilepsy is a complex neurological disorder which can severely affect neuronal function. Some patients may experience status epilepticus, a life-threatening state of ongoing seizure activity associated with postictal cognitive dysfunction. However, the molecular mechanisms by which status epilepticus influences brain function beyond seizure activity remain not well understood. Here, we addressed the question of whether pilocarpine-induced status epilepticus affects synaptopodin (SP), an actin-binding protein, which regulates the ability of neurons to express synaptic plasticity. This makes SP an interesting marker for epilepsy-associated alterations in synaptic function. Indeed, single dose intraperitoneal pilocarpine injection (250 mg/kg) in three-month-old male C57BL/6J mice leads to a rapid reduction in hippocampal SP-cluster sizes and numbers (in CA1 stratum radiatum of the dorsal hippocampus; 90 min after injection). In line with this observation (and previous work using SP-deficient mice), a defect in the ability to induce long-term potentiation (LTP) of Schaffer collateral-CA1 synapses is observed. Based on these findings we propose that status epilepticus could exert its aftereffects on cognition at least in part by perturbing SP-dependent mechanisms of synaptic plasticity.
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22
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Walker MC. Pathophysiology of status epilepticus. Neurosci Lett 2016; 667:84-91. [PMID: 28011391 DOI: 10.1016/j.neulet.2016.12.044] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/16/2016] [Accepted: 12/17/2016] [Indexed: 12/22/2022]
Abstract
Status epilepticus (SE) is the maximal expression of epilepsy with a high morbidity and mortality. It occurs due to the failure of mechanisms that terminate seizures. Both human and animal data indicate that the longer a seizure lasts, the less likely it is to stop. Recent evidence suggests that there is a critical transition from an ictal to a post-ictal state, associated with a transition from a spatio-temporally desynchronized state to a highly synchronized state, respectively. As SE continues, it becomes progressively resistant to drugs, in particular benzodiazepines due partly to NMDA receptor-dependent internalization of GABA(A) receptors. Moreover, excessive calcium entry into neurons through excessive NMDA receptor activation results in activation of nitric oxide synthase, calpains, and NADPH oxidase. The latter enzyme plays a critical part in the generation of seizure-dependent reactive oxygen species. Calcium also accumulates in mitochondria resulting in mitochondrial failure (decreased ATP production), and opening of the mitochondrial permeability transition pore. Together these changes result in status epilepticus-dependent neuronal death via several pathways. Multiple downstream mechanisms including inflammation, break down of the blood-brain barrier, and changes in gene expression can contribute to later pathological processes including chronic epilepsy and cognitive decline.
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Affiliation(s)
- Matthew C Walker
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London WC1N 3BG, United Kingdom.
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Abstract
Although the majority of seizures are brief and cause no long-term consequences, a subset is sufficiently prolonged that long-term consequences can result. These very prolonged seizures are termed "status epilepticus" (SE) and are considered a neurological emergency. The clinical presentation of SE can be diverse. SE can occur at any age but most commonly occurs in the very young and the very old. There are numerous studies on SE in animals in which the pathophysiology, medication responses, and pathology can be rigorously studied in a controlled fashion. Human data are consistent with the animal data. In particular, febrile status epilepticus (FSE), a form of SE common in young children, is associated with injury to the hippocampus and subsequent temporal lobe epilepsy (TLE) in both animals and humans.
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Affiliation(s)
- Syndi Seinfeld
- Virginia Commonwealth University, Richmond, Virginia 23298-0211
| | | | - Shlomo Shinnar
- Comprehensive Epilepsy Management Center, Montefiore Medical Center, Albert Einstein College of Medicine, New York, New York 10467
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Liu Y, Xu X, Xie J, Ma H, Wang T, Zhang G, Li Q. Design, Synthesis, and Biological Evaluation of Novel CNS 7056 Derivatives as Sedatives in Rats and Rabbits. Chem Biol Drug Des 2016; 88:38-42. [PMID: 26820491 DOI: 10.1111/cbdd.12731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 01/05/2016] [Accepted: 01/21/2016] [Indexed: 10/22/2022]
Abstract
A new water-soluble benzodiazepine derivative, CNS 7056 (named as remimazolam), has been undergoing many reactions in recent years to provide an intravenous agent with a predictable fast-onset, short duration of action, and rapid recovery profile. Based on the structure of CNS 7056 with proven activity, seven new CNS 7056 derivatives were designed, and their sedative activities upon mouse, rats, and rabbits were examined. Sedative activities of EL-001˜007 were screened. The results indicated that the shorter the side chain at C3 position is, the higher the sedative activity is. EL-001 was chosen as the optimal compound for studies of ED50 , LD50 , latency to LRR and the duration of LRR, and its anesthetic activity was compared with that of CNS 7056 in rats and rabbits. Studies showed that EL-001 is a potent sedative in rodent and lagomorpha, with a short duration of action. Compared with CNS 7056, EL-001 has a shorter period of induction despite a slightly longer sedative duration and recovery time.
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Affiliation(s)
- Yan Liu
- Division of Medicinal Chemistry, School of Pharmacy, Chongqing Medical University, Chongqing, 400010, China
| | - Xiangqing Xu
- R&D Department, Jiangsu Nhwa Pharmaceutical Corporation Ltd., Jiangsu, 221009, China
| | - Jianyong Xie
- Division of Medicinal Chemistry, School of Pharmacy, Chongqing Medical University, Chongqing, 400010, China
| | - Huan Ma
- Division of Medicinal Chemistry, School of Pharmacy, Chongqing Medical University, Chongqing, 400010, China
| | - Tao Wang
- R&D Department, Jiangsu Nhwa Pharmaceutical Corporation Ltd., Jiangsu, 221009, China
| | - Guisen Zhang
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Qingeng Li
- Division of Medicinal Chemistry, School of Pharmacy, Chongqing Medical University, Chongqing, 400010, China
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