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Wang SH, Lee DS, Kim TH, Kim JE, Kang TC. Reciprocal regulation of oxidative stress and mitochondrial fission augments parvalbumin downregulation through CDK5-DRP1- and GPx1-NF-κB signaling pathways. Cell Death Dis 2024; 15:707. [PMID: 39349423 PMCID: PMC11443148 DOI: 10.1038/s41419-024-07050-5] [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: 02/25/2024] [Revised: 09/01/2024] [Accepted: 09/03/2024] [Indexed: 10/02/2024]
Abstract
Loss of parvalbumin (PV) expressing neurons (PV neurons) is relevant to the underlying mechanisms of the pathogenesis of neurological and psychiatric diseases associated with the dysregulation of neuronal excitatory networks and brain metabolism. Although PV modulates mitochondrial morphology, volume and dynamics, it is largely unknown whether mitochondrial dynamics affect PV expression and what the molecular events are responsible for PV neuronal degeneration. In the present study, L-buthionine sulfoximine (BSO, an inhibitor of glutathione synthesis) did not degenerate PV neurons under physiological condition. However, BSO-induced oxidative stress decreased PV expression and facilitated cyclin-dependent kinase 5 (CDK5) tyrosine (Y) 15 phosphorylation, dynamin-related protein 1 (DRP1)-mediated mitochondrial fission and glutathione peroxidase-1 (GPx1) downregulation in PV neurons. Co-treatment of roscovitine (a CDK5 inhibitor) or mitochondrial division inhibitor-1 (Mdivi-1, an inhibitor of mitochondrial fission) attenuated BSO-induced PV downregulation. WY14643 (an inducer of mitochondrial fission) reduced PV expression without affecting CDK5 Y15 phosphorylation. Following status epilepticus (SE), CDK5 Y15 phosphorylation and mitochondrial fission were augmented in PV neurons. These were accompanied by reduced GPx1-mediated inhibition of NF-κB p65 serine (S) 536 phosphorylation. N-acetylcysteine (NAC), roscovitine and Mdivi-1 ameliorated SE-induced PV neuronal degeneration by mitigating CDK5 Y15 hyperphosphorylation, aberrant mitochondrial fragmentation and reduced GPx1-mediated NF-κB inhibition. Furthermore, SN50 (a NF-κB inhibitor) alleviated SE-induced PV neuronal degeneration, independent of dysregulation of mitochondrial fission, CDK5 hyperactivation and GPx1 downregulation. These findings provide an evidence that oxidative stress may activate CDK5-DRP1- and GPx1-NF-κB-mediated signaling pathways, which would be possible therapeutic targets for preservation of PV neurons in various diseases.
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Affiliation(s)
- Su Hyeon Wang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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2
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Junghans K, Wyeth M, Buckmaster PS. Rat strain differences in seizure frequency and hilar neuron loss after systemic treatment with pilocarpine. Epilepsy Res 2024; 204:107384. [PMID: 38879905 PMCID: PMC11253724 DOI: 10.1016/j.eplepsyres.2024.107384] [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: 02/13/2024] [Revised: 05/13/2024] [Accepted: 05/29/2024] [Indexed: 06/18/2024]
Abstract
At least 3 months after systemic treatment with pilocarpine to induce status epilepticus, Long-Evans and Sprague-Dawley rats were video-EEG monitored for seizures continuously for 1 month. Rats were then perfused, hippocampi were processed for Nissl staining, and hilar neurons were quantified. Seizure frequency in Long-Evans rats was 1/10th of that in Sprague-Dawley rats, and more variable. Hilar neuron loss was also less severe in Long-Evans rats. However, there was no correlation between hilar neuron loss and seizure frequency in either strain. The low and variable seizure frequency suggests limited usefulness of pilocarpine-treated Long-Evans rats for some epilepsy experiments.
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Affiliation(s)
- Kristina Junghans
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
| | - Megan Wyeth
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA.
| | - Paul S Buckmaster
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA; Departments of Neurology & Neurological Sciences, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
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3
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Mardones MD, Rostam KD, Nickerson MC, Gupta K. Canonical Wnt activator Chir99021 prevents epileptogenesis in the intrahippocampal kainate mouse model of temporal lobe epilepsy. Exp Neurol 2024; 376:114767. [PMID: 38522659 PMCID: PMC11058011 DOI: 10.1016/j.expneurol.2024.114767] [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: 12/20/2023] [Revised: 02/29/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
The Wnt signaling pathway mediates the development of dentate granule cell neurons in the hippocampus. These neurons are central to the development of temporal lobe epilepsy and undergo structural and physiological remodeling during epileptogenesis, which results in the formation of epileptic circuits. The pathways responsible for granule cell remodeling during epileptogenesis have yet to be well defined, and represent therapeutic targets for the prevention of epilepsy. The current study explores Wnt signaling during epileptogenesis and for the first time describes the effect of Wnt activation using Wnt activator Chir99021 as a novel anti-epileptogenic therapeutic approach. Focal mesial temporal lobe epilepsy was induced by intrahippocampal kainate (IHK) injection in wild-type and POMC-eGFP transgenic mice. Wnt activator Chir99021 was administered daily, beginning 3 h after seizure induction, and continued up to 21-days. Immature granule cell morphology was quantified in the ipsilateral epileptogenic zone and the contralateral peri-ictal zone 14 days after IHK, targeting the end of the latent period. Bilateral hippocampal electrocorticographic recordings were performed for 28-days, 7-days beyond treatment cessation. Hippocampal behavioral tests were performed after completion of Chir99021 treatment. Consistent with previous studies, IHK resulted in the development of epilepsy after a 14 day latent period in this well-described mouse model. Activation of the canonical Wnt pathway with Chir99021 significantly reduced bilateral hippocampal seizure number and duration. Critically, this effect was retained after treatment cessation, suggesting a durable antiepileptogenic change in epileptic circuitry. Morphological analyses demonstrated that Wnt activation prevented pathological remodeling of the primary dendrite in both the epileptogenic zone and peri-ictal zone, changes in which may serve as a biomarker of epileptogenesis and anti-epileptogenic treatment response in pre-clinical studies. These findings were associated with improved object location memory with Chir99021 treatment after IHK. This study provides novel evidence that canonical Wnt activation prevents epileptogenesis in the IHK mouse model of mesial temporal lobe epilepsy, preventing pathological remodeling of dentate granule cells. Wnt signaling may therefore play a key role in mesial temporal lobe epileptogenesis, and Wnt modulation may represent a novel therapeutic strategy in the prevention of epilepsy.
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Affiliation(s)
- Muriel D Mardones
- Indiana University, Stark Neurosciences Research Institute, W 15th St, Indianapolis, IN 46202, United States of America; Indiana University, Department of Neurosurgery, W 16th St, Indianapolis, IN 46202, United States of America.
| | - Kevin D Rostam
- Indiana University, Stark Neurosciences Research Institute, W 15th St, Indianapolis, IN 46202, United States of America.
| | - Margaret C Nickerson
- Indiana University, Stark Neurosciences Research Institute, W 15th St, Indianapolis, IN 46202, United States of America.
| | - Kunal Gupta
- Medical College of Wisconsin, Department of Neurosurgery, 8701 Watertown Plank Rd, Milwaukee, WI 53226, United States of America; Medical College of Wisconsin, Neuroscience Research Center, 8701 Watertown Plank Rd, Milwaukee, WI 53226, United States of America; Indiana University, Stark Neurosciences Research Institute, W 15th St, Indianapolis, IN 46202, United States of America; Indiana University, Department of Neurosurgery, W 16th St, Indianapolis, IN 46202, United States of America.
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4
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Lee SH, Kang YJ, Smith BN. Activation of hypoactive parvalbumin-positive fast-spiking interneuron restores dentate inhibition to prevent epileptiform activity in the mouse intrahippocampal kainate model of temporal lobe epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.05.588316. [PMID: 38645248 PMCID: PMC11030452 DOI: 10.1101/2024.04.05.588316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Parvalbumin-positive (PV+) GABAergic interneurons in the dentate gyrus provide powerful perisomatic inhibition of dentate granule cells (DGCs) to prevent overexcitation and maintain the stability of dentate gyrus circuits. Most dentate PV+ interneurons survive status epilepticus, but surviving PV+ interneuron mediated inhibition is compromised in the dentate gyrus shortly after status epilepticus, contributing to epileptogenesis in temporal lobe epilepsy. It is uncertain whether the impaired activity of dentate PV+ interneurons recovers at later times or if it continues for months following status epilepticus. The development of compensatory modifications related to PV+ interneuron circuits in the months following status epilepticus is unknown, although reduced dentate GABAergic inhibition persists long after status epilepticus. We employed PV immunostaining and whole-cell patch-clamp recordings from dentate PV+ interneurons and DGCs in slices from male and female sham controls and intrahippocampal kainate (IHK) treated mice that developed spontaneous seizures months after status epilepticus to study epilepsy-associated changes in dentate PV+ interneuron circuits. We found that the number of dentate PV+ cells was reduced in IHK treated mice. Electrical recordings showed that: 1) Action potential firing rates of dentate PV+ interneurons were reduced in IHK treated mice up to four months after status epilepticus; 2) Spontaneous inhibitory postsynaptic currents (sIPSCs) in DGCs exhibited reduced frequency but increased amplitude in IHK treated mice; and 3) The amplitude of evoked IPSCs in DGCs by optogenetic activation of dentate PV+ cells was upregulated without changes in short-term plasticity. Video-EEG recordings revealed that IHK treated mice showed spontaneous epileptiform activity in the dentate gyrus and that chemogenetic activation of PV+ interneurons abolished the epileptiform activity. Our results suggest not only that the compensatory changes in PV+ interneuron circuits develop after IHK treatment, but also that increased PV+ interneuron mediated inhibition in the dentate gyrus may compensate for cell loss and reduced intrinsic excitability of dentate PV+ interneurons to stop seizures in temporal lobe epilepsy. Highlights Reduced number of dentate PV+ interneurons in TLE micePersistently reduced action potential firing rates of dentate PV+ interneurons in TLE miceEnhanced amplitude but decreased frequency of spontaneous IPSCs in the dentate gyrus in TLE miceIncreased amplitude of evoked IPSCs mediated by dentate PV+ interneurons in TLE miceChemogenetic activation of PV+ interneurons prevents epileptiform activity in TLE mice.
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Kruk PK, Nader K, Skupien-Jaroszek A, Wójtowicz T, Buszka A, Olech-Kochańczyk G, Wilczynski GM, Worch R, Kalita K, Włodarczyk J, Dzwonek J. Astrocytic CD44 Deficiency Reduces the Severity of Kainate-Induced Epilepsy. Cells 2023; 12:1483. [PMID: 37296604 PMCID: PMC10252631 DOI: 10.3390/cells12111483] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/05/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
BACKGROUND Epilepsy affects millions of people worldwide, yet we still lack a successful treatment for all epileptic patients. Most of the available drugs modulate neuronal activity. Astrocytes, the most abundant cells in the brain, may constitute alternative drug targets. A robust expansion of astrocytic cell bodies and processes occurs after seizures. Highly expressed in astrocytes, CD44 adhesion protein is upregulated during injury and is suggested to be one of the most important proteins associated with epilepsy. It connects the astrocytic cytoskeleton to hyaluronan in the extracellular matrix, influencing both structural and functional aspects of brain plasticity. METHODS Herein, we used transgenic mice with an astrocyte CD44 knockout to evaluate the impact of the hippocampal CD44 absence on the development of epileptogenesis and ultrastructural changes at the tripartite synapse. RESULTS We demonstrated that local, virally-induced CD44 deficiency in hippocampal astrocytes reduces reactive astrogliosis and decreases the progression of kainic acid-induced epileptogenesis. We also observed that CD44 deficiency resulted in structural changes evident in a higher dendritic spine number along with a lower percentage of astrocyte-synapse contacts, and decreased post-synaptic density size in the hippocampal molecular layer of the dentate gyrus. CONCLUSIONS Overall, our study indicates that CD44 signaling may be important for astrocytic coverage of synapses in the hippocampus and that alterations of astrocytes translate to functional changes in the pathology of epilepsy.
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Affiliation(s)
- Patrycja K. Kruk
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Karolina Nader
- Laboratory of Neurobiology, Nencki-EMBL Partnership for Neural Plasticity and Brain Disorders-Braincity, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Anna Skupien-Jaroszek
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Tomasz Wójtowicz
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Anna Buszka
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Gabriela Olech-Kochańczyk
- Laboratory of Molecular and Structural Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Grzegorz M. Wilczynski
- Laboratory of Molecular and Structural Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Remigiusz Worch
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Katarzyna Kalita
- Laboratory of Neurobiology, Nencki-EMBL Partnership for Neural Plasticity and Brain Disorders-Braincity, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Jakub Włodarczyk
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
| | - Joanna Dzwonek
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteura St, 02-093 Warsaw, Poland
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Chloride ion dysregulation in epileptogenic neuronal networks. Neurobiol Dis 2023; 177:106000. [PMID: 36638891 DOI: 10.1016/j.nbd.2023.106000] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/25/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
GABA is the major inhibitory neurotransmitter in the mature CNS. When GABAA receptors are activated the membrane potential is driven towards hyperpolarization due to chloride entry into the neuron. However, chloride ion dysregulation that alters the ionic gradient can result in depolarizing GABAergic post-synaptic potentials instead. In this review, we highlight that GABAergic inhibition prevents and restrains focal seizures but then reexamine this notion in the context of evidence that a static and/or a dynamic chloride ion dysregulation, that increases intracellular chloride ion concentrations, promotes epileptiform activity and seizures. To reconcile these findings, we hypothesize that epileptogenic pathologically interconnected neuron (PIN) microcircuits, representing a small minority of neurons, exhibit static chloride dysregulation and should exhibit depolarizing inhibitory post-synaptic potentials (IPSPs). We speculate that chloride ion dysregulation and PIN cluster activation may generate fast ripples and epileptiform spikes as well as initiate the hypersynchronous seizure onset pattern and microseizures. Also, we discuss the genetic, molecular, and cellular players important in chloride dysregulation which regulate epileptogenesis and initiate the low-voltage fast seizure onset pattern. We conclude that chloride dysregulation in neuronal networks appears to be critical for epileptogenesis and seizure genesis, but feed-back and feed-forward inhibitory GABAergic neurotransmission plays an important role in preventing and restraining seizures as well.
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7
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Yang N, Chen YB, Zhang YF. The rearrangement of actin cytoskeleton in mossy fiber synapses in a model of experimental febrile seizures. Front Neurol 2023; 14:1107538. [PMID: 37181554 PMCID: PMC10170767 DOI: 10.3389/fneur.2023.1107538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/10/2023] [Indexed: 05/16/2023] Open
Abstract
Background Experimental complex febrile seizures induce a persistent hippocampal hyperexcitability and an enhanced seizure susceptibility in adulthood. The rearrangement of filamentous actin (F-actin) enhances the excitability of hippocampus and contributes to epileptogenesis in epileptic models. However, the remodeling of F-actin after prolonged febrile seizures is to be determined. Methods Prolonged experimental febrile seizures were induced by hyperthermia on P10 and P14 rat pups. Changes of actin cytoskeleton in hippocampal subregions were examined at P60 and the neuronal cells and pre- /postsynaptic components were labeled. Results F-actin was increased significantly in the stratum lucidum of CA3 region in both HT + 10D and HT + 14D groups and further comparison between the two groups showed no significant difference. The abundance of ZNT3, the presynaptic marker of mossy fiber (MF)-CA3 synapses, increased significantly whereas the postsynaptic marker PSD95 did not change significantly. Overlapping area of F-actin and ZNT3 showed a significant increase in both HT+ groups. The results of cell counts showed no significant increase or decrease in the number of neurons in each area of hippocampus. Conclusion F-actin was significantly up-regulated in the stratum lucidum of CA3, corresponding to the increase of the presynaptic marker of MF-CA3 synapses after prolonged febrile seizures, which may enhance the excitatory output from the dentate gyrus to CA3 and contribute to the hippocampal hyperexcitability.
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Affiliation(s)
- Nuo Yang
- Department of Pediatric Neurology, The First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Yin-Bo Chen
- Department of Pediatric Neurology, The First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Yan-Feng Zhang
- Department of Pediatric Neurology, The First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
- *Correspondence: Yan-Feng Zhang,
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Bae S, Lim HK, Jeong Y, Kim SG, Park SM, Shon YM, Suh M. Deep brain stimulation of the anterior nuclei of the thalamus can alleviate seizure severity and induce hippocampal GABAergic neuronal changes in a pilocarpine-induced epileptic mouse brain. Cereb Cortex 2022; 32:5530-5543. [PMID: 35258078 DOI: 10.1093/cercor/bhac033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 01/25/2023] Open
Abstract
Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) has been widely used as an effective treatment for refractory temporal lobe epilepsy. Despite its promising clinical outcome, the exact mechanism of how ANT-DBS alleviates seizure severity has not been fully understood, especially at the cellular level. To assess effects of DBS, the present study examined electroencephalography (EEG) signals and locomotor behavior changes and conducted immunohistochemical analyses to examine changes in neuronal activity, number of neurons, and neurogenesis of inhibitory neurons in different hippocampal subregions. ANT-DBS alleviated seizure activity, abnormal locomotor behaviors, reduced theta-band, increased gamma-band EEG power in the interictal state, and increased the number of neurons in the dentate gyrus (DG). The number of parvalbumin- and somatostatin-expressing inhibitory neurons was recovered to the level in DG and CA1 of naïve mice. Notably, BrdU-positive inhibitory neurons were increased. In conclusion, ANT-DBS not only could reduce the number of seizures, but also could induce neuronal changes in the hippocampus, which is a key region involved in chronic epileptogenesis. Importantly, our results suggest that ANT-DBS may lead to hippocampal subregion-specific cellular recovery of GABAergic inhibitory neurons.
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Affiliation(s)
- Sungjun Bae
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea.,IMNEWRUN Inc., N Center Bldg. A 5F, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hyun-Kyoung Lim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, South Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon 16419, South Korea
| | - Yoonyi Jeong
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea
| | - Sung-Min Park
- Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea
| | - Young-Min Shon
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon 16419, South Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea.,IMNEWRUN Inc., N Center Bldg. A 5F, Sungkyunkwan University, Suwon 16419, South Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon 16419, South Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon 16419, South Korea
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Mardones MD, Gupta K. Transcriptome Profiling of the Hippocampal Seizure Network Implicates a Role for Wnt Signaling during Epileptogenesis in a Mouse Model of Temporal Lobe Epilepsy. Int J Mol Sci 2022; 23:12030. [PMID: 36233336 PMCID: PMC9569502 DOI: 10.3390/ijms231912030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/17/2022] Open
Abstract
Mesial temporal lobe epilepsy (mTLE) is a life-threatening condition characterized by recurrent hippocampal seizures. mTLE can develop after exposure to risk factors such as febrile seizure, trauma, and infection. Within the latent period between exposure and onset of epilepsy, pathological remodeling events occur that contribute to epileptogenesis. The molecular mechanisms responsible are currently unclear. We used the mouse intrahippocampal kainite model of mTLE to investigate transcriptional dysregulation in the ipsilateral and contralateral dentate gyrus (DG), representing the epileptogenic zone (EZ) and peri-ictal zone (PIZ). DG were analyzed after 3, 7, and 14 days by RNA sequencing. In both the EZ and PIZ, transcriptional dysregulation was dynamic over the epileptogenic period with early expression of genes representing cell signaling, migration, and proliferation. Canonical Wnt signaling was upregulated in the EZ and PIZ at 3 days. Expression of inflammatory genes differed between the EZ and PIZ, with early expression after 3 days in the PIZ and delayed expression after 7-14 days in the EZ. This suggests that critical gene changes occur early in the hippocampal seizure network and that Wnt signaling may play a role within the latent epileptogenic period. These findings may help to identify novel therapeutic targets that could prevent epileptogenesis.
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Affiliation(s)
- Muriel D Mardones
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kunal Gupta
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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10
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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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11
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Lehmann L, Lo A, Knox KM, Barker-Haliski M. Alzheimer's Disease and Epilepsy: A Perspective on the Opportunities for Overlapping Therapeutic Innovation. Neurochem Res 2021; 46:1895-1912. [PMID: 33929683 PMCID: PMC8254705 DOI: 10.1007/s11064-021-03332-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 01/01/2023]
Abstract
Early-onset Alzheimer's disease (AD) is associated with variants in amyloid precursor protein (APP) and presenilin (PSEN) 1 and 2. It is increasingly recognized that patients with AD experience undiagnosed focal seizures. These AD patients with reported seizures may have worsened disease trajectory. Seizures in epilepsy can also lead to cognitive deficits, neuroinflammation, and neurodegeneration. Epilepsy is roughly three times more common in individuals aged 65 and older. Due to the numerous available antiseizure drugs (ASDs), treatment of seizures has been proposed to reduce the burden of AD. More work is needed to establish the functional impact of seizures in AD to determine whether ASDs could be a rational therapeutic strategy. The efficacy of ASDs in aged animals is not routinely studied, despite the fact that the elderly represents the fastest growing demographic with epilepsy. This leaves a particular gap in understanding the discrete pathophysiological overlap between hyperexcitability and aging, and AD more specifically. Most of our preclinical knowledge of hyperexcitability in AD has come from mouse models that overexpress APP. While these studies have been invaluable, other drivers underlie AD, e.g. PSEN2. A diversity of animal models should be more frequently integrated into the study of hyperexcitability in AD, which could be particularly beneficial to identify novel therapies. Specifically, AD-associated risk genes, in particular PSENs, altogether represent underexplored contributors to hyperexcitability. This review assesses the available studies of ASDs administration in clinical AD populations and preclinical studies with AD-associated models and offers a perspective on the opportunities for further therapeutic innovation.
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Affiliation(s)
- Leanne Lehmann
- Undergraduate Neuroscience Program, University of Washington, Seattle, WA, 98195, USA
| | - Alexandria Lo
- Department of Public Health-Global Health, School of Public Health, University of Washington, Seattle, WA, 98195, USA
| | - Kevin M Knox
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA, 98195, USA
| | - Melissa Barker-Haliski
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA, 98195, USA.
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12
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Chiprés-Tinajero GA, Núñez-Ochoa MA, Medina-Ceja L. Increased immunoreactivity of glutamate receptors, neuronal nuclear protein and glial fibrillary acidic protein in the hippocampus of epileptic rats with fast ripple activity. Exp Brain Res 2021; 239:2015-2024. [PMID: 33909110 DOI: 10.1007/s00221-021-06108-6] [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: 10/07/2020] [Accepted: 04/08/2021] [Indexed: 11/28/2022]
Abstract
Epilepsy is a neurological disorder in which an imbalance between excitatory and inhibitory transmission is observed. Glutamate is the principal excitatory neurotransmitter that acts through ionic and metabotropic receptors; both types of receptors are involved in temporal lobe epilepsy (TLE). High frequency oscillations called fast ripples (FR, 250-600 Hz) have been observed, particularly in the hippocampus, and they are involved in epileptogenesis. The present study analyzed the immunoreactivity of the principal glutamate receptors associated with epilepsy in epileptic animals with FR activity. Male Swiss-Wistar rats (210-250 gr) were injected with pilocarpine (2.4 mg/2 µl) and were video monitored (24/7) until the appearance of spontaneous and recurrent seizures. Then, a deep microelectrode implantation surgery was performed in the DG, CA3 and CA1 regions, and FR activity was observed 1-, 2-, 3-, 7-, and 14-day postsurgery. The animals were sacrificed on day 15, and fluorescence immunohistochemistry was carried out in the hippocampus for the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), N-methyl-D-aspartate (NMDA) and mGlu-R5 glutamate receptors as well as Neuronal Nuclear Protein (NeuN) and Glial Fibrillary Acidic Protein (GFAP). An increase in the immunoreactivity for the three receptors was found. However, the AMPA receptor showed an increase in the three regions analyzed (i.e., DG, CA1 and CA3). The findings showed a decrease of NeuN in the DG and an increase of GFAP. These results suggest an important role of glutamate receptors in the hippocampus of epileptic rats with FR activity.
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Affiliation(s)
- Gustavo A Chiprés-Tinajero
- Laboratory of Neurophysiology, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, 45110, México
| | - Miguel A Núñez-Ochoa
- Laboratory of Neurophysiology, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, 45110, México
| | - Laura Medina-Ceja
- Laboratory of Neurophysiology, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, 45110, México.
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13
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Slomianka L. Basic quantitative morphological methods applied to the central nervous system. J Comp Neurol 2021; 529:694-756. [PMID: 32639600 PMCID: PMC7818269 DOI: 10.1002/cne.24976] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/19/2022]
Abstract
Generating numbers has become an almost inevitable task associated with studies of the morphology of the nervous system. Numbers serve a desire for clarity and objectivity in the presentation of results and are a prerequisite for the statistical evaluation of experimental outcomes. Clarity, objectivity, and statistics make demands on the quality of the numbers that are not met by many methods. This review provides a refresher of problems associated with generating numbers that describe the nervous system in terms of the volumes, surfaces, lengths, and numbers of its components. An important aim is to provide comprehensible descriptions of the methods that address these problems. Collectively known as design-based stereology, these methods share two features critical to their application. First, they are firmly based in mathematics and its proofs. Second and critically underemphasized, an understanding of their mathematical background is not necessary for their informed and productive application. Understanding and applying estimators of volume, surface, length or number does not require more of an organizational mastermind than an immunohistochemical protocol. And when it comes to calculations, square roots are the gravest challenges to overcome. Sampling strategies that are combined with stereological probes are efficient and allow a rational assessment if the numbers that have been generated are "good enough." Much may be unfamiliar, but very little is difficult. These methods can no longer be scapegoats for discrepant results but faithfully produce numbers on the material that is assessed. They also faithfully reflect problems that associated with the histological material and the anatomically informed decisions needed to generate numbers that are not only valid in theory. It is within reach to generate practically useful numbers that must integrate with qualitative knowledge to understand the function of neural systems.
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Affiliation(s)
- Lutz Slomianka
- University of Zürich, Institute of AnatomyZürichSwitzerland
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14
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Beesley S, Sullenberger T, Ailani R, D'Orio C, Crockett MS, Kumar SS. d-Serine Intervention In The Medial Entorhinal Area Alters TLE-Related Pathology In CA1 Hippocampus Via The Temporoammonic Pathway. Neuroscience 2021; 453:168-186. [PMID: 33197499 PMCID: PMC7796904 DOI: 10.1016/j.neuroscience.2020.10.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/15/2023]
Abstract
Entrainment of the hippocampus by the medial entorhinal area (MEA) in Temporal Lobe Epilepsy (TLE), the most common type of drug-resistant epilepsy in adults, is believed to be mediated primarily through the perforant pathway (PP), which connects stellate cells in layer (L) II of the MEA with granule cells of the dentate gyrus (DG) to drive the hippocampal tri-synaptic circuit. Using immunohistochemistry, high-resolution confocal microscopy and the rat pilocarpine model of TLE, we show here that the lesser known temporoammonic pathway (TAP) plays a significant role in transferring MEA pathology to the CA1 region of the hippocampus independently of the PP. The pathology observed was region-specific and restricted primarily to the CA1c subfield of the hippocampus. As shown previously, daily intracranial infusion of d-serine (100 μm), an antagonist of GluN3-containing triheteromeric N-Methyl d-aspartate receptors (t-NMDARs), into the MEA prevented loss of LIII neurons and epileptogenesis. This intervention in the MEA led to the rescue of hippocampal CA1 neurons that would have otherwise perished in the epileptic animals, and down regulation of the expression of astrocytes and microglia thereby mitigating the effects of neuroinflammation. Interestingly, these changes were not observed to a similar extent in other regions of vulnerability like the hilus, DG or CA3, suggesting that the pathology manifest in CA1 is driven predominantly through the TAP. This work highlights TAP's role in the entrainment of the hippocampus and identifies specific areas for therapeutic intervention in dealing with TLE.
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Affiliation(s)
- Stephen Beesley
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States
| | - Thomas Sullenberger
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States
| | - Roshan Ailani
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States
| | - Cameron D'Orio
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States
| | - Mathew S Crockett
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States
| | - Sanjay S Kumar
- Department of Biomedical Sciences, College of Medicine & Program in Neuroscience, Florida State University, 1115 W. Call Street, Tallahassee, FL 32306-4300, United States.
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15
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LaSarge CL, Pun RYK, Gu Z, Riccetti MR, Namboodiri DV, Tiwari D, Gross C, Danzer SC. mTOR-driven neural circuit changes initiate an epileptogenic cascade. Prog Neurobiol 2020; 200:101974. [PMID: 33309800 DOI: 10.1016/j.pneurobio.2020.101974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/22/2020] [Accepted: 12/05/2020] [Indexed: 11/29/2022]
Abstract
Mutations in genes regulating mTOR pathway signaling are now recognized as a significant cause of epilepsy. Interestingly, these mTORopathies are often caused by somatic mutations, affecting variable numbers of neurons. To better understand how this variability affects disease phenotype, we developed a mouse model in which the mTOR pathway inhibitor Pten can be deleted from 0 to 40 % of hippocampal granule cells. In vivo, low numbers of knockout cells caused focal seizures, while higher numbers led to generalized seizures. Generalized seizures coincided with the loss of local circuit interneurons. In hippocampal slices, low knockout cell loads produced abrupt reductions in population spike threshold, while spontaneous excitatory postsynaptic currents and circuit level recurrent activity increased gradually with rising knockout cell load. Findings demonstrate that knockout cells load is a critical variable regulating disease phenotype, progressing from subclinical circuit abnormalities to electrobehavioral seizures with secondary involvement of downstream neuronal populations.
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Affiliation(s)
- Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Raymund Y K Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Zhiqing Gu
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Shanghai Children's Hospital, Shanghai, 200062, China
| | - Matthew R Riccetti
- Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Devi V Namboodiri
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christina Gross
- Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States; Department of Anesthesia, University of Cincinnati, Cincinnati, OH, 45267, United States.
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16
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Wyeth M, Nagendran M, Buckmaster PS. Ictal onset sites and γ-aminobutyric acidergic neuron loss in epileptic pilocarpine-treated rats. Epilepsia 2020; 61:856-867. [PMID: 32242932 DOI: 10.1111/epi.16490] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The present study tested whether ictal onset sites are regions of more severe interneuron loss in epileptic pilocarpine-treated rats, a model of human temporal lobe epilepsy. METHODS Local field potential recordings were evaluated to identify ictal onset sites. Electrode sites were visualized in Nissl-stained sections. Adjacent sections were processed with proximity ligation in situ hybridization for glutamic acid decarboxylase 2 (Gad2). Gad2 neuron profile numbers at ictal onset sites were compared to contralateral regions. Other sections were processed with immunocytochemistry for reelin or nitric oxide synthase (NOS), which labeled major subtypes of granule cell layer-associated interneurons. Stereology was used to estimate numbers of reelin and NOS granule cell layer-associated interneurons per hippocampus. RESULTS Ictal onset sites varied between and within rats but were mostly in the ventral hippocampus and were frequently bilateral. There was no conclusive evidence of more severe Gad2 neuron profile loss at sites of earliest seizure activity compared to contralateral regions. Numbers of granule cell layer-associated NOS neurons were reduced in the ventral hippocampus. SIGNIFICANCE In epileptic pilocarpine-treated rats, ictal onset sites were mostly in the ventral hippocampus, where there was loss of granule cell layer-associated NOS interneurons. These findings suggest the hypothesis that loss of granule cell layer-associated NOS interneurons in the ventral hippocampus is a mechanism of temporal lobe epilepsy.
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Affiliation(s)
- Megan Wyeth
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Monica Nagendran
- Department of Medicine-Pulmonary and Critical Care, Stanford University, Stanford, California
| | - Paul S Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California.,Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
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17
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Wilcox KS, West PJ, Metcalf CS. The current approach of the Epilepsy Therapy Screening Program contract site for identifying improved therapies for the treatment of pharmacoresistant seizures in epilepsy. Neuropharmacology 2020; 166:107811. [PMID: 31790717 PMCID: PMC7054975 DOI: 10.1016/j.neuropharm.2019.107811] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/05/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022]
Abstract
The Epilepsy Therapy Screening Program (ETSP), formerly known as the Anticonvulsant Screening Program (ASP), has played an important role in the preclinical evaluation of many of the antiseizure drugs (ASDs) that have been approved by the FDA and thus made available for the treatment of seizures. Recent changes to the animal models used at the contract site of the ETSP at the University of Utah have been implemented in an attempt to better model the unmet clinical needs of people with pharmacoresistant epilepsy and thus identify improved therapies. In this review, we describe the changes that have occurred over the last several years in the screening approach used at the contract site and, in particular, detail the pharmacology associated with several of the animal models and assays that are either new to the program or have been recently characterized in more depth. There is optimism that the refined approach used by the ETSP contract site, wherein etiologically relevant models that include those with spontaneous seizures are used, will identify novel, potentially disease modifying therapies for people with pharmacoresistant epilepsy and those at risk for developing epilepsy. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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Affiliation(s)
- Karen S Wilcox
- Anticonvulsant Drug Development (ADD) Program, Department of Pharmacology & Toxicology, University of Utah, USA.
| | - Peter J West
- Anticonvulsant Drug Development (ADD) Program, Department of Pharmacology & Toxicology, University of Utah, USA.
| | - Cameron S Metcalf
- Anticonvulsant Drug Development (ADD) Program, Department of Pharmacology & Toxicology, University of Utah, USA.
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18
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Maia GH, Soares JI, Almeida SG, Leite JM, Baptista HX, Lukoyanova AN, Brazete CS, Lukoyanov NV. Altered serotonin innervation in the rat epileptic brain. Brain Res Bull 2019; 152:95-106. [DOI: 10.1016/j.brainresbull.2019.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 06/28/2019] [Accepted: 07/08/2019] [Indexed: 01/19/2023]
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19
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Zhang L, Sun W, Xu L, Wang Y, Zhu G, Wu X, Wang Y, Hong Z. The anticonvulsant and neuroprotective effects of kir2.3 activation in PTZ-induced seizures and the kainic acid model of TLE. Epilepsy Res 2019; 156:106167. [PMID: 31336325 DOI: 10.1016/j.eplepsyres.2019.106167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 07/06/2019] [Accepted: 07/12/2019] [Indexed: 01/01/2023]
Abstract
PURPOSE To elucidate the role of activating the inwardly rectifying K+ channel 2.3 (Kir2.3) in acute seizure and chronic epilepsy, we investigated the effect of a Kir2.3 agonist (tenidap) on epileptic and electrophysiological activities in mice. Neuronal excitability and damage were also evaluated. METHODS A Pentylenetetrazole (PTZ)-induced acute seizure model and a kainic acid (KA)-induced temporal epilepsy model were used in adult mice. The mice were given tenidap 30 min before PTZ injection or were given tenidap for 7 days after entering the chronic stage of the KA model. Video monitoring and EEG recordings were performed for comparisons. Immunofluorescence of c-fos was detected in the PTZ model, and Nissl staining was performed in the KA model. RESULTS Tenidap intervention significantly reduced the duration and severity of PTZ-induced acute seizures, which conformed with the power-spectrum analyses of the EEG and the quantification of spikes on EEG. C-fos expression representing neuronal excitability was also reduced with tenidap pretreatment. However, the latency time to seizure onset was unaltered. Seven days of tenidap treatment in the chronic KA model significantly attenuated seizure and spike frequencies compared to the same animal before administration. Nissl staining showed reduced hilar neuron loss in the tenidap-intervention group but showed no difference in the width of the granule cell layer. CONCLUSION To our knowledge, few studies have reported the relevance of Kir2.3 to epilepsy. The present data suggested that activation of Kir2.3 exerts an anticonvulsant effect in acute seizures and the chronic stage of TLE, which makes this channel a potent therapeutic target.
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Affiliation(s)
- Lu Zhang
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Wanbing Sun
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Lan Xu
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Yue Wang
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Guoxing Zhu
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Xunyi Wu
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China.
| | - Yun Wang
- Institutes of Brain Science, Department of Neurology at Zhongshan Hospital, Fudan University, Shanghai 200032, China.
| | - Zhen Hong
- Department of Neurology at Huashan Hospital, Fudan University, Shanghai 200032, China
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20
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de Curtis M, Librizzi L, Uva L, Gnatkovsky V. GABAA receptor-mediated networks during focal seizure onset and progression in vitro. Neurobiol Dis 2019; 125:190-197. [DOI: 10.1016/j.nbd.2019.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/08/2019] [Accepted: 02/07/2019] [Indexed: 02/02/2023] Open
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21
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Cameron S, Lopez A, Glabman R, Abrams E, Johnson S, Field C, Gulland FMD, Buckmaster PS. Proportional loss of parvalbumin-immunoreactive synaptic boutons and granule cells from the hippocampus of sea lions with temporal lobe epilepsy. J Comp Neurol 2019; 527:2341-2355. [PMID: 30861128 DOI: 10.1002/cne.24680] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/18/2019] [Accepted: 03/02/2019] [Indexed: 01/10/2023]
Abstract
One in 26 people develop epilepsy and in these temporal lobe epilepsy (TLE) is common. Many patients display a pattern of neuron loss called hippocampal sclerosis. Seizures usually start in the hippocampus but underlying mechanisms remain unclear. One possibility is insufficient inhibition of dentate granule cells. Normally parvalbumin-immunoreactive (PV) interneurons strongly inhibit granule cells. Humans with TLE display loss of PV interneurons in the dentate gyrus but questions persist. To address this, we evaluated PV interneuron and bouton numbers in California sea lions (Zalophus californianus) that naturally develop TLE after exposure to domoic acid, a neurotoxin that enters the marine food chain during harmful algal blooms. Sclerotic hippocampi were identified by the loss of Nissl-stained hilar neurons. Stereological methods were used to estimate the number of granule cells and PV interneurons per dentate gyrus. Sclerotic hippocampi contained fewer granule cells, fewer PV interneurons, and fewer PV synaptic boutons, and the ratio of granule cells to PV interneurons was higher than in controls. To test whether fewer boutons was attributable to loss versus reduced immunoreactivity, expression of synaptotagmin-2 (syt2) was evaluated. Syt2 is also expressed in boutons of PV interneurons. Sclerotic hippocampi displayed proportional losses of syt2-immunoreactive boutons, PV boutons, and granule cells. There was no significant difference in the average numbers of PV- or syt2-positive boutons per granule cell between control and sclerotic hippocampi. These findings do not address functionality of surviving synapses but suggest reduced granule cell inhibition in TLE is not attributable to anatomical loss of PV boutons.
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Affiliation(s)
- Starr Cameron
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Ariana Lopez
- Department of Comparative Medicine, Stanford University, Stanford, California.,College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Raisa Glabman
- Department of Comparative Medicine, Stanford University, Stanford, California.,School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Emily Abrams
- Department of Comparative Medicine, Stanford University, Stanford, California
| | | | - Cara Field
- The Marine Mammal Center, Sausalito, California
| | | | - Paul S Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California.,Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
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22
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Sears SMS, Hewett JA, Hewett SJ. Decreased epileptogenesis in mice lacking the System x c - transporter occurs in association with a reduction in AMPA receptor subunit GluA1. Epilepsia Open 2019; 4:133-143. [PMID: 30868123 PMCID: PMC6398109 DOI: 10.1002/epi4.12307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/19/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Although the cystine/glutamate antiporter System xc - (Sxc -) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sxc - contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. METHODS Male Sxc - null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sxc - light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K+/Cl- co-transporter KCC2 were quantified via western blot analysis. RESULTS Repeated administration of PTZ produced chemical kindling in only 50% of Sxc - null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sxc - null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sxc - null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. SIGNIFICANCE This study provides the first evidence that Sxc - signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sxc - null mice.
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Affiliation(s)
- Sheila M. S. Sears
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
| | - James A. Hewett
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
| | - Sandra J. Hewett
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
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23
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Leibowitz JA, Natarajan G, Zhou J, Carney PR, Ormerod BK. Sustained somatostatin gene expression reverses kindling-induced increases in the number of dividing Type-1 neural stem cells in the hippocampi of behaviorally responsive rats. Epilepsy Res 2019; 150:78-94. [PMID: 30735971 DOI: 10.1016/j.eplepsyres.2019.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/18/2018] [Accepted: 01/10/2019] [Indexed: 12/13/2022]
Abstract
Neurogenesis persists throughout life in the hippocampi of all mammals, including humans. In the healthy hippocampus, relatively quiescent Type-1 neural stem cells (NSCs) can give rise to more proliferative Type-2a neural progenitor cells (NPCs), which generate neuronal-committed Type-2b NPCs that mature into Type-3 neuroblasts. Many Type-3 neuroblasts survive and mature into functionally integrated granule neurons over several weeks. In kindling models of epilepsy, neurogenesis is drastically upregulated and many new neurons form aberrant connections that could support epileptogenesis and/or seizures. We have shown that sustained vector-mediated hippocampal somatostatin (SST) expression can both block epileptogenesis and reverse seizure susceptibility in fully kindled rats. Here we test whether adeno-associated virus (AAV) vector-mediated sustained SST expression modulates hippocampal neurogenesis and microglial activation in fully kindled rats. We found significantly more dividing Type-1 NSCs and a corresponding increased number of surviving new neurons in the hippocampi of kindled versus sham-kindled rats. Increased numbers of activated microglia were found in the granule cell layer and hilus of kindled rats at both time points. After intrahippocampal injection with either eGFP or SST-eGFP vector, we found similar numbers of dividing Type-1 NSCs and -2 NPCs and surviving BrdU+ neurons and glia in the hippocampi of kindled rats. Upon observed variability in responses to SST-eGFP (2/4 rats exhibited Grade 0 seizures in the test session), we conducted an additional experiment. We found significantly fewer dividing Type-1 NSCs in the hippocampi of SST-eGFP vector-treated responder rats (5/13 rats) relative to SST-eGFP vector-treated non-responders and eGFP vector-treated controls that exhibited high-grade seizures on the test session. The number of activated microglia was upregulated in the GCL and hilus of kindled rats, regardless of vector treatment. These data support the hypothesis that sustained SST expression exerts antiepileptic effects potentially through normalization of neurogenesis and suggests that abnormally high proliferating Type-1 NSC numbers may be a cellular mechanism of epilepsy.
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Affiliation(s)
| | - Gowri Natarajan
- Department of Neurology and Pediatrics, USA; Neuroscience Program, USA
| | - Junli Zhou
- Department of Neurology and Pediatrics, USA; Neuroscience Program, USA
| | - Paul R Carney
- Department of Neurology and Pediatrics, USA; Neuroscience Program, USA; Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Brandi K Ormerod
- J. Crayton Pruitt Family Department of Biomedical Engineering, USA; Department of Neuroscience, USA; McKnight Brain Institute, USA.
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24
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Singh N, Saha L, Kumari P, Singh J, Bhatia A, Banerjee D, Chakrabarti A. Effect of dimethyl fumarate on neuroinflammation and apoptosis in pentylenetetrazol kindling model in rats. Brain Res Bull 2019; 144:233-245. [DOI: 10.1016/j.brainresbull.2018.11.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/05/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022]
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25
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Frankowski JC, Kim YJ, Hunt RF. Selective vulnerability of hippocampal interneurons to graded traumatic brain injury. Neurobiol Dis 2018; 129:208-216. [PMID: 30031783 DOI: 10.1016/j.nbd.2018.07.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/26/2018] [Accepted: 07/18/2018] [Indexed: 12/21/2022] Open
Abstract
Traumatic brain injury is a major risk factor for many long-term mental health problems. Although underlying mechanisms likely involve compromised inhibition, little is known about how individual subpopulations of interneurons are affected by neurotrauma. Here we report long-term loss of hippocampal interneurons following controlled cortical impact (CCI) injury in young-adult mice, a model of focal cortical contusion injury in humans. Brain injured mice displayed subfield and cell-type specific decreases in interneurons 30 days after impact depths of 0.5 mm and 1.0 mm, and increasing the depth of impact led to greater cell loss. In general, we found a preferential reduction of interneuron cohorts located in principal cell and polymorph layers, while cell types positioned in the molecular layer appeared well preserved. Our results suggest a dramatic shift of interneuron diversity following contusion injury that may contribute to the pathophysiology of traumatic brain injury.
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Affiliation(s)
- Jan C Frankowski
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Young J Kim
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA.
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26
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Kelley MR, Cardarelli RA, Smalley JL, Ollerhead TA, Andrew PM, Brandon NJ, Deeb TZ, Moss SJ. Locally Reducing KCC2 Activity in the Hippocampus is Sufficient to Induce Temporal Lobe Epilepsy. EBioMedicine 2018; 32:62-71. [PMID: 29884458 PMCID: PMC6020795 DOI: 10.1016/j.ebiom.2018.05.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 12/03/2022] Open
Abstract
Mesial temporal lobe epilepsy (mTLE) is the most common form of epilepsy, believed to arise in part from compromised GABAergic inhibition. The neuronal specific K+/Cl- co-transporter 2 (KCC2) is a critical determinant of the efficacy of GABAergic inhibition and deficits in its activity are observed in mTLE patients and animal models of epilepsy. To test if reductions of KCC2 activity directly contribute to the pathophysiology of mTLE, we locally ablated KCC2 expression in a subset of principal neurons within the adult hippocampus. Deletion of KCC2 resulted in compromised GABAergic inhibition and the development of spontaneous, recurrent generalized seizures. Moreover, local ablation of KCC2 activity resulted in hippocampal sclerosis, a key pathological change seen in mTLE. Collectively, our results demonstrate that local deficits in KCC2 activity within the hippocampus are sufficient to precipitate mTLE.
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Affiliation(s)
- Matt R Kelley
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Ross A Cardarelli
- AstraZeneca-Tufts University Laboratory for Basic and Translational Neuroscience Research, Boston, MA, USA
| | - Joshua L Smalley
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Thomas A Ollerhead
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Peter M Andrew
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Nicholas J Brandon
- AstraZeneca-Tufts University Laboratory for Basic and Translational Neuroscience Research, Boston, MA, USA; Neuroscience, IMED Biotech Unit, AstraZeneca, Boston, MA, USA
| | - Tarek Z Deeb
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA; AstraZeneca-Tufts University Laboratory for Basic and Translational Neuroscience Research, Boston, MA, USA
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA; AstraZeneca-Tufts University Laboratory for Basic and Translational Neuroscience Research, Boston, MA, USA; Neuroscience, IMED Biotech Unit, AstraZeneca, Boston, MA, USA; Department of Neuroscience, Physiology and Pharmacology, University College, London, WC1E, 6BT, UK.
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27
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Choi YS, Horning P, Aten S, Karelina K, Alzate-Correa D, Arthur JSC, Hoyt KR, Obrietan K. Mitogen- and Stress-Activated Protein Kinase 1 Regulates Status Epilepticus-Evoked Cell Death in the Hippocampus. ASN Neuro 2018; 9:1759091417726607. [PMID: 28870089 PMCID: PMC5588809 DOI: 10.1177/1759091417726607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) signaling has been implicated in a wide range of neuronal processes, including development, plasticity, and viability. One of the principal downstream targets of both the extracellular signal-regulated kinase/MAPK pathway and the p38 MAPK pathway is Mitogen- and Stress-activated protein Kinase 1 (MSK1). Here, we sought to understand the role that MSK1 plays in neuroprotection against excitotoxic stimulation in the hippocampus. To this end, we utilized immunohistochemical labeling, a MSK1 null mouse line, cell viability assays, and array-based profiling approaches. Initially, we show that MSK1 is broadly expressed within the major neuronal cell layers of the hippocampus and that status epilepticus drives acute induction of MSK1 activation. In response to the status epilepticus paradigm, MSK1 KO mice exhibited a striking increase in vulnerability to pilocarpine-evoked cell death within the CA1 and CA3 cell layers. Further, cultured MSK1 null neurons exhibited a heighted level of N-methyl-D-aspartate-evoked excitotoxicity relative to wild-type neurons, as assessed using the lactate dehydrogenase assay. Given these findings, we examined the hippocampal transcriptional profile of MSK1 null mice. Affymetrix array profiling revealed that MSK1 deletion led to the significant (>1.25-fold) downregulation of 130 genes and an upregulation of 145 genes. Notably, functional analysis indicated that a subset of these genes contribute to neuroprotective signaling networks. Together, these data provide important new insights into the mechanism by which the MAPK/MSK1 signaling cassette confers neuroprotection against excitotoxic insults. Approaches designed to upregulate or mimic the functional effects of MSK1 may prove beneficial against an array of degenerative processes resulting from excitotoxic insults.
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Affiliation(s)
- Yun-Sik Choi
- 1 Department of Pharmaceutical Science and Technology, Catholic University of Daegu, Gyeongbuk, Republic of Korea
| | - Paul Horning
- 2 Department of Neuroscience, 2647 Ohio State University , Columbus, OH, USA
| | - Sydney Aten
- 2 Department of Neuroscience, 2647 Ohio State University , Columbus, OH, USA
| | - Kate Karelina
- 2 Department of Neuroscience, 2647 Ohio State University , Columbus, OH, USA
| | | | - J Simon C Arthur
- 4 College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Kari R Hoyt
- 3 Division of Pharmacology, 2647 Ohio State University , Columbus, OH, USA
| | - Karl Obrietan
- 2 Department of Neuroscience, 2647 Ohio State University , Columbus, OH, USA
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28
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Chiang S, Vannucci M, Goldenholz DM, Moss R, Stern JM. Epilepsy as a dynamic disease: A Bayesian model for differentiating seizure risk from natural variability. Epilepsia Open 2018; 3:236-246. [PMID: 29881802 PMCID: PMC5983137 DOI: 10.1002/epi4.12112] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2018] [Indexed: 01/07/2023] Open
Abstract
Objective A fundamental challenge in treating epilepsy is that changes in observed seizure frequencies do not necessarily reflect changes in underlying seizure risk. Rather, changes in seizure frequency may occur due to probabilistic variation around an underlying seizure risk state caused by normal fluctuations from natural history, leading to seizure unpredictability and potentially suboptimal medication adjustments in epilepsy management. However, no rigorous statistical approach exists to systematically distinguish expected changes in seizure frequency due to natural variability from changes in underlying seizure risk. Methods Using data from SeizureTracker.com, a patient‐reported seizure diary tool containing over 1.2 million recorded seizures across 8 years, a novel epilepsy seizure risk assessment tool (EpiSAT) employing a Bayesian mixed‐effects hidden Markov model for zero‐inflated count data was developed to estimate changes in underlying seizure risk using patient‐reported seizure diary and clinical measurement data. Accuracy for correctly assessing underlying seizure risk was evaluated through a simulation comparison. Implications for the natural history of tuberous sclerosis complex (TSC) were assessed using data from SeizureTracker.com. Results EpiSAT led to significant improvement in seizure risk assessment compared to traditional approaches relying solely on observed seizure frequencies. Applied to TSC, four underlying seizure risk states were identified. The expected duration of each state was <12 months, providing a data‐driven estimate of the amount of time a person with TSC would be expected to remain at the same seizure risk level according to the natural course of epilepsy. Significance We propose a novel Bayesian statistical approach for evaluating seizure risk on an individual patient level using patient‐reported seizure diaries, which allows for the incorporation of external clinical variables to assess impact on seizure risk. This tool may improve the ability to distinguish true changes in seizure risk from natural variations in seizure frequency in clinical practice. Incorporation of systematic statistical approaches into antiepileptic drug (AED) management may help improve understanding of seizure unpredictability as well as timing of treatment interventions for people with epilepsy.
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Affiliation(s)
- Sharon Chiang
- School of Medicine Baylor College of Medicine Houston Texas U.S.A.,Department of Statistics Rice University Houston Texas U.S.A
| | - Marina Vannucci
- Department of Statistics Rice University Houston Texas U.S.A
| | - Daniel M Goldenholz
- Division of Epilepsy Beth Israel Deaconess Medical Center Boston Massachusetts U.S.A.,Clinical Epilepsy Section National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda Maryland U.S.A
| | - Robert Moss
- SeizureTracker.com Alexandria Virginia U.S.A
| | - John M Stern
- Department of Neurology University of California Los Angeles Los Angeles California U.S.A
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29
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Khan AA, Shekh-Ahmad T, Khalil A, Walker MC, Ali AB. Cannabidiol exerts antiepileptic effects by restoring hippocampal interneuron functions in a temporal lobe epilepsy model. Br J Pharmacol 2018; 175:2097-2115. [PMID: 29574880 PMCID: PMC5979781 DOI: 10.1111/bph.14202] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/13/2017] [Accepted: 02/27/2018] [Indexed: 12/29/2022] Open
Abstract
Background and Purpose A non‐psychoactive phytocannabinoid, cannabidiol (CBD), shows promising results as an effective potential antiepileptic drug in some forms of refractory epilepsy. To elucidate the mechanisms by which CBD exerts its anti‐seizure effects, we investigated its effects at synaptic connections and on the intrinsic membrane properties of hippocampal CA1 pyramidal cells and two major inhibitory interneurons: fast spiking, parvalbumin (PV)‐expressing and adapting, cholecystokinin (CCK)‐expressing interneurons. We also investigated whether in vivo treatment with CBD altered the fate of CCK and PV interneurons using immunohistochemistry. Experimental Approach Electrophysiological intracellular whole‐cell recordings combined with neuroanatomy were performed in acute brain slices of rat temporal lobe epilepsy in in vivo (induced by kainic acid) and in vitro (induced by Mg2+‐free solution) epileptic seizure models. For immunohistochemistry experiments, CBD was administered in vivo (100 mg·kg−1) at zero time and 90 min post status epilepticus, induced with kainic acid. Key Results Bath application of CBD (10 μM) dampened excitability at unitary synapses between pyramidal cells but enhanced inhibitory synaptic potentials elicited by fast spiking and adapting interneurons at postsynaptic pyramidal cells. Furthermore, CBD restored impaired membrane excitability of PV, CCK and pyramidal cells in a cell type‐specific manner. These neuroprotective effects of CBD were corroborated by immunohistochemistry experiments that revealed a significant reduction in atrophy and death of PV‐ and CCK‐expressing interneurons after CBD treatment. Conclusions and Implications Our data suggest that CBD restores excitability and morphological impairments in epileptic models to pre‐epilepsy control levels through multiple mechanisms to reinstate normal network function.
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Affiliation(s)
| | | | | | | | - Afia B Ali
- UCL School of Pharmacy, London, WC1N 1AX, UK
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30
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Becker AJ. Review: Animal models of acquired epilepsy: insights into mechanisms of human epileptogenesis. Neuropathol Appl Neurobiol 2018; 44:112-129. [DOI: 10.1111/nan.12451] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/27/2017] [Indexed: 02/06/2023]
Affiliation(s)
- A. J. Becker
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn Medical Center; Bonn Germany
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31
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Smith ZZ, Benison AM, Bercum FM, Dudek FE, Barth DS. Progression of convulsive and nonconvulsive seizures during epileptogenesis after pilocarpine-induced status epilepticus. J Neurophysiol 2018; 119:1818-1835. [PMID: 29442558 DOI: 10.1152/jn.00721.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although convulsive seizures occurring during pilocarpine-induced epileptogenesis have received considerable attention, nonconvulsive seizures have not been closely examined, even though they may reflect the earliest signs of epileptogenesis and potentially guide research on antiepileptogenic interventions. The definition of nonconvulsive seizures based on brain electrical activity alone has been controversial. Here we define and quantify electrographic properties of convulsive and nonconvulsive seizures in the context of the acquired epileptogenesis that occurs after pilocarpine-induced status epilepticus (SE). Lithium-pilocarpine was used to induce the prolonged repetitive seizures characteristic of SE; when SE was terminated with paraldehyde, seizures returned during the 2-day period after pilocarpine treatment. A distinct latent period ranging from several days to >2 wk was then measured with continuous, long-term video-EEG. Nonconvulsive seizures dominated the onset of epileptogenesis and consistently preceded the first convulsive seizures but were still present later. Convulsive and nonconvulsive seizures had similar durations. Postictal depression (background suppression of the EEG) lasted for >100 s after both convulsive and nonconvulsive seizures. Principal component analysis was used to quantify the spectral evolution of electrical activity that characterized both types of spontaneous recurrent seizures. These studies demonstrate that spontaneous nonconvulsive seizures have electrographic properties similar to convulsive seizures and confirm that nonconvulsive seizures link the latent period and the onset of convulsive seizures during post-SE epileptogenesis in an animal model. Nonconvulsive seizures may also reflect the earliest signs of epileptogenesis in human acquired epilepsy, when intervention could be most effective. NEW & NOTEWORTHY Nonconvulsive seizures usually represent the first bona fide seizure following a latent period, dominate the early stages of epileptogenesis, and change in severity in a manner consistent with the progressive nature of epileptogenesis. This analysis demonstrates that nonconvulsive and convulsive seizures have different behavioral outcomes but similar electrographic signatures. Alternatively, epileptiform spike-wave discharges fail to recapitulate several key seizure features and represent a category of electrical activity separate from nonconvulsive seizures in this model.
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Affiliation(s)
- Zachariah Z Smith
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - Alexander M Benison
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - Florencia M Bercum
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah School of Medicine , Salt Lake City, Utah
| | - Daniel S Barth
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
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32
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Fukumura S, Sasaki M, Kataoka-Sasaki Y, Oka S, Nakazaki M, Nagahama H, Morita T, Sakai T, Tsutsumi H, Kocsis JD, Honmou O. Intravenous infusion of mesenchymal stem cells reduces epileptogenesis in a rat model of status epilepticus. Epilepsy Res 2018; 141:56-63. [PMID: 29475054 DOI: 10.1016/j.eplepsyres.2018.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/22/2018] [Accepted: 02/13/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Status epilepticus (SE) causes neuronal cell death, aberrant mossy fiber sprouting (MFS), and cognitive deteriorations. The present study tested the hypothesis that systemically infused mesenchymal stem cells (MSCs) reduce epileptogenesis by inhibiting neuronal cell death and suppressing aberrant MFS, leading to cognitive function preservation in a rat model of epilepsy. METHODS SE was induced using the lithium-pilocarpine injection model. The seizure frequency was scored using a video-monitoring system and the Morris water maze test was carried out to evaluate cognitive function. Comparisons were made between MSCs- and vehicle-infused rats. Immunohistochemical staining was performed to detect Green fluorescent protein (GFP)+ MSCs and to quantify the number of GAD67+ and NeuN+ neurons in the hippocampus. Manganese-enhanced magnetic resonance imaging (MEMRI) and Timm staining were also performed to assess the MFS. RESULTS MSC infusion inhibited epileptogenesis and preserved cognitive function after SE. The infused GFP+ MSCs were accumulated in the hippocampus and were associated with the preservation of GAD67+ and NeuN+ hippocampal neurons. Furthermore, the MSC infusion suppressed the aberrant MFS in the hippocampus as evidenced by MEMRI and Timm staining. CONCLUSIONS This study demonstrated that the intravenous infusion of MSCs mitigated epileptogenesis, thus advancing MSCs as an effective approach for epilepsy in clinical practice.
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Affiliation(s)
- Shinobu Fukumura
- Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan; Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Masanori Sasaki
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan; Department of Neurology, Yale University School of Medicine, New Haven, CT, 06510, USA; Center for Neuroscience and Regeneration Research, VA Connecticut Healthcare System, West Haven, CT, 06516, USA.
| | - Yuko Kataoka-Sasaki
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Shinichi Oka
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Masahito Nakazaki
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Hiroshi Nagahama
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Tomonori Morita
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Takuro Sakai
- Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan; Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Hiroyuki Tsutsumi
- Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan
| | - Jeffery D Kocsis
- Department of Neurology, Yale University School of Medicine, New Haven, CT, 06510, USA; Center for Neuroscience and Regeneration Research, VA Connecticut Healthcare System, West Haven, CT, 06516, USA
| | - Osamu Honmou
- Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan; Department of Neurology, Yale University School of Medicine, New Haven, CT, 06510, USA; Center for Neuroscience and Regeneration Research, VA Connecticut Healthcare System, West Haven, CT, 06516, USA
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33
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Sanon NT, Gagné J, Wolf DC, Aboulamer S, Bosoi CM, Simard A, Messiet E, Desgent S, Carmant L. Favorable adverse effect profile of brivaracetam vs levetiracetam in a preclinical model. Epilepsy Behav 2018; 79:117-125. [PMID: 29287214 DOI: 10.1016/j.yebeh.2017.11.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/15/2017] [Accepted: 11/19/2017] [Indexed: 10/18/2022]
Abstract
Levetiracetam (LEV), and its newer selective analog brivaracetam (BRV), are two seizure medications that share an innovative mechanism of action targeting the Synaptic Vesicle Protein 2A (SV2A), altering neurotransmitter release and decreasing seizure frequency. Behavioral changes are the most significant adverse effects reported by patients taking LEV. We hypothesize that BRV, the more potent SV2A analog, could exert less behavioral side effects, as it requires lower doses than LEV. Using Kainic Acid (KA)-treated and control rats, we measured adverse behavioral effect profiles of LEV, BRV, or Saline, on social and nonsocial behaviors. Our data indicate that both tested drugs had no effect on locomotion, anxiety levels, fear learning, depression-like behavior, and memory retention in rats. However, when considering social interactions, we first confirmed the epilepsy-induced strong increase in aggressive behaviors and specific hippocampal neuronal loss. We furthermore observed, in Sham rats, that LEV-treated animals were 2 times faster to attack at first encounter, had 5 times more aggressive behaviors, and had significantly less social behaviors than control rats. In all circumstances, BRV rats behaved like Saline rats, suggesting that BRV treatment in rats leads to significantly less aggressive behaviors than LEV treatment at the doses used, while there are limited differential effects between these two drugs on other types of behaviors. Since increased aggressiveness has been reported in patients well controlled on LEV, this study indicates based on our findings, that BRV could represent an effective alternative to LEV to limit aggressiveness problems due to this antiepileptic drug (AED) therapy.
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Affiliation(s)
- Nathalie T Sanon
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada.
| | - Jonathan Gagné
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada; Département de Sciences Biomédicales, Université de Montréal, Québec, Canada
| | - Daniele C Wolf
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada
| | - Soumia Aboulamer
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada
| | - Ciprian M Bosoi
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada
| | - Alexe Simard
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada
| | - Estelle Messiet
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada
| | - Sébastien Desgent
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada
| | - Lionel Carmant
- Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada.
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34
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Sieu LA, Eugène E, Bonnot A, Cohen I. Disrupted Co-activation of Interneurons and Hippocampal Network after Focal Kainate Lesion. Front Neural Circuits 2017; 11:87. [PMID: 29180954 PMCID: PMC5693904 DOI: 10.3389/fncir.2017.00087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 10/26/2017] [Indexed: 12/02/2022] Open
Abstract
GABAergic interneurons are known to control activity balance in physiological conditions and to coordinate hippocampal networks during cognitive tasks. In temporal lobe epilepsy interneuron loss and consecutive network imbalance could favor pathological hypersynchronous epileptic discharges. We tested this hypothesis in mice by in vivo unilateral epileptogenic hippocampal kainate lesion followed by in vitro recording of extracellular potentials and patch-clamp from GFP-expressing interneurons in CA3, in an optimized recording chamber. Slices from lesioned mice displayed, in addition to control synchronous events, larger epileptiform discharges. Despite some ipsi/contralateral and layer variation, interneuron density tended to decrease, average soma size to increase. Their membrane resistance decreased, capacitance increased and contralateral interneuron required higher current intensity to fire action potentials. Examination of synchronous discharges of control and larger amplitudes, revealed that interneurons were biased to fire predominantly with the largest population discharges. Altogether, these observations suggest that the overall effect of reactive cell loss, hypertrophy and reduced contralateral excitability corresponds to interneuron activity tuning to fire with larger population discharges. Such cellular and network mechanisms may contribute to a runaway path toward epilepsy.
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Affiliation(s)
- Lim-Anna Sieu
- Institut de Biologie Paris Seine, UPMC/INSERM UMRS1130/CNRS UMR8246, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.,Neuroscience Paris Seine (UMR-S 1130), Institut de Biologie Paris-Seine, INSERM, Paris, France
| | - Emmanuel Eugène
- Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.,Institut du Fer à Moulin, UPMC/INSERM UMRS839, Paris, France
| | - Agnès Bonnot
- Institut de Biologie Paris Seine, UPMC/INSERM UMRS1130/CNRS UMR8246, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.,Neuroscience Paris Seine (UMR-S 1130), Institut de Biologie Paris-Seine, INSERM, Paris, France
| | - Ivan Cohen
- Institut de Biologie Paris Seine, UPMC/INSERM UMRS1130/CNRS UMR8246, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.,Neuroscience Paris Seine (UMR-S 1130), Institut de Biologie Paris-Seine, INSERM, Paris, France
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35
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Ehara A, Maekawa M, Hori Y, Nakadate K, Ueda S. Age-related behavioral, morphological and physiological changes in the hippocampus of zitter rats. Anat Sci Int 2017; 93:332-339. [DOI: 10.1007/s12565-017-0416-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
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36
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Gu F, Parada I, Shen F, Li J, Bacci A, Graber K, Taghavi RM, Scalise K, Schwartzkroin P, Wenzel J, Prince DA. Structural alterations in fast-spiking GABAergic interneurons in a model of posttraumatic neocortical epileptogenesis. Neurobiol Dis 2017; 108:100-114. [PMID: 28823934 DOI: 10.1016/j.nbd.2017.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 01/22/2023] Open
Abstract
Electrophysiological experiments in the partial cortical isolation ("undercut" or "UC") model of injury-induced neocortical epileptogenesis have shown alterations in GABAergic synaptic transmission attributable to abnormalities in presynaptic terminals. To determine whether the decreased inhibition was associated with structural abnormalities in GABAergic interneurons, we used immunocytochemical techniques, confocal microscopy and EM in UC and control sensorimotor rat cortex to analyze structural alterations in fast-spiking parvalbumin-containing interneurons and pyramidal (Pyr) cells of layer V. Principle findings were: 1) there were no decreases in counts of parvalbumin (PV)- or GABA-immunoreactive interneurons in UC cortex, however there were significant reductions in expression of VGAT and GAD-65 and -67 in halos of GABAergic terminals around Pyr somata in layer V. 2) Consistent with previous results, somatic size and density of Pyr cells was decreased in infragranular layers of UC cortex. 3) Dendrites of biocytin-filled FS interneurons were significantly decreased in volume. 4) There were decreases in the size and VGAT content of GABAergic boutons in axons of biocytin-filled FS cells in the UC, together with a decrease in colocalization with postsynaptic gephyrin, suggesting a reduction in GABAergic synapses. Quantitative EM of layer V Pyr somata confirmed the reduction in inhibitory synapses. 5) There were marked and lasting reductions in brain derived neurotrophic factor (BDNF)-IR and -mRNA in Pyr cells and decreased TrkB-IR on PV cells in UC cortex. 6) Results lead to the hypothesis that reduction in trophic support by BDNF derived from Pyr cells may contribute to the regressive changes in axonal terminals and dendrites of FS cells in the UC cortex and decreased GABAergic inhibition. SIGNIFICANCE Injury to cortical structures is a major cause of epilepsy, accounting for about 20% of cases in the general population, with an incidence as high as ~50% among brain-injured personnel in wartime. Loss of GABAergic inhibitory interneurons is a significant pathophysiological factor associated with epileptogenesis following brain trauma and other etiologies. Results of these experiments show that the largest population of cortical interneurons, the parvalbumin-containing fast-spiking (FS) interneurons, are preserved in the partial neocortical isolation model of partial epilepsy. However, axonal terminals of these cells are structurally abnormal, have decreased content of GABA synthetic enzymes and vesicular GABA transporter and make fewer synapses onto pyramidal neurons. These structural abnormalities underlie defects in GABAergic neurotransmission that are a key pathophysiological factor in epileptogenesis found in electrophysiological experiments. BDNF, and its TrkB receptor, key factors for maintenance of interneurons and pyramidal neurons, are decreased in the injured cortex. Results suggest that supplying BDNF to the injured epileptogenic brain may reverse the structural and functional abnormalities in the parvalbumin FS interneurons and provide an antiepileptogenic therapy.
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Affiliation(s)
- Feng Gu
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Isabel Parada
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Fran Shen
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Judith Li
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Alberto Bacci
- ICM - Hôpital Pitié Salpêtrière, 7, bd de l'hôpital, 75013 Paris, France
| | - Kevin Graber
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Reza Moein Taghavi
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Karina Scalise
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States
| | - Philip Schwartzkroin
- Department of Neurological Surgery, University of California, Davis, United States
| | - Jurgen Wenzel
- Department of Neurological Surgery, University of California, Davis, United States
| | - David A Prince
- Epilepsy Research Laboratories, Stanford Univ. Sch. of Medicine, United States.
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Buckmaster PS, Abrams E, Wen X. Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy. J Comp Neurol 2017; 525:2592-2610. [PMID: 28425097 PMCID: PMC5963263 DOI: 10.1002/cne.24226] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 01/19/2023]
Abstract
Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31-61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24-36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy.
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Affiliation(s)
- Paul S. Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
| | - Emily Abrams
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Xiling Wen
- Department of Comparative Medicine, Stanford University, Stanford, California
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Faria LC, Gu F, Parada I, Barres B, Luo ZD, Prince DA. Epileptiform activity and behavioral arrests in mice overexpressing the calcium channel subunit α2δ-1. Neurobiol Dis 2017; 102:70-80. [PMID: 28193459 DOI: 10.1016/j.nbd.2017.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/17/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022] Open
Abstract
The alpha2delta-1 subunit (α2δ-1) of voltage-gated calcium channels is a receptor for astrocyte-secreted thrombospondins that promote developmental synaptogenesis. Alpha2delta-1 receptors are upregulated in models of injury-induced peripheral pain and epileptogenic neocortical trauma associated with an enhancement of excitatory synaptic connectivity. These results lead to the hypothesis that overexpression of α2δ-1 alone in neocortex of uninjured transgenic (TG) mice might result in increased excitatory connectivity and consequent cortical hyperexcitability and epileptiform activity. Whole cell recordings from layer V pyramidal neurons in somatosensory cortical slices of TG mice showed increased frequency and amplitude of miniature and spontaneous EPSCs and prolonged bursts of polysynaptic EPSCs. Epileptiform field potentials were evoked in layers II/III and V of brain slices from TG mice, but not controls. Dual immunoreactivity for Vglut-2 and PSD95 showed increased density of close appositions in TG mice compared to controls, suggesting an increased number of excitatory synapses. Video-EEG monitoring showed that 13/13 implanted TG mice aged >P21, but not controls, had frequent abnormal spontaneous epileptiform events, consisting of variable duration, high amplitude bi-hemispheric irregular bursts of delta activity, spikes and sharp waves lasting many seconds, with a variable peak frequency of ~1-3Hz, associated with behavioral arrest. The epileptiform EEG abnormalities and behavioral arrests were reversibly eliminated by treatment with i.p. ethosuximide. Behavioral seizures, consisting of ~15-30s duration episodes of rigid arched tail and head and body extension, followed by loss of balance and falling, frequently occurred in adult TG mice during recovery from isoflurane-induced anesthesia, but were rare in WT mice. Results show that over-expression of α2δ-1 subunits increases cortical excitatory connectivity and leads to neocortical hyperexcitability and epileptiform activity associated with behavioral arrests in adult TG mice. Similar increases in expression of α2δ-1 in models of cortical injury may play an important role in epileptogenesis. SIGNIFICANCE Binding of astrocytic-secreted thrombospondins to their α2δ-1 receptor facilitates excitatory synapse formation and excitatory transmission during cortical development and after injury. Upregulation of α2δ-1 is present in models of injury-induced pain and epileptogenic cortical trauma, along with many other molecular alterations. Here we show that overexpression of α2δ-1 alone in TG mice can enhance excitatory connectivity in neocortex and lead to neural circuit hyperexcitability and episodes of electrographic epileptiform activity, associated with behavioral arrests in transgenic mice. α2δ-1 is the high-affinity receptor for gabapentinoids and a potential target for prophylactic treatment of posttraumatic epilepsy and other disorders in which excessive aberrant excitatory connectivity is a pathophysiological feature.
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Affiliation(s)
- Leonardo C Faria
- Department of Neurology and Neurological Sciences, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Feng Gu
- Department of Neurology and Neurological Sciences, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Isabel Parada
- Department of Neurology and Neurological Sciences, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Ben Barres
- Department of Neurobiology, Stanford University, Howard Hughes Medical Institute, Stanford School of Medicine, Stanford, CA 94305-5125, USA
| | - Z David Luo
- Department of Anesthesiology and Perioperative Care, Department of Pharmacology, University of California, Irvine Medical Center, Orange, CA 92868, USA
| | - David A Prince
- Department of Neurology and Neurological Sciences, Stanford University, School of Medicine, Stanford, CA 94305, USA.
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Clossen BL, Reddy DS. Novel therapeutic approaches for disease-modification of epileptogenesis for curing epilepsy. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1519-1538. [PMID: 28179120 PMCID: PMC5474195 DOI: 10.1016/j.bbadis.2017.02.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 11/16/2022]
Abstract
This article describes the recent advances in epileptogenesis and novel therapeutic approaches for the prevention of epilepsy, with a special emphasis on the pharmacological basis of disease-modification of epileptogenesis for curing epilepsy. Here we assess animal studies and human clinical trials of epilepsy spanning 1982-2016. Epilepsy arises from a number of neuronal factors that trigger epileptogenesis, which is the process by which a brain shifts from a normal physiologic state to an epileptic condition. The events precipitating these changes can be of diverse origin, including traumatic brain injury, cerebrovascular damage, infections, chemical neurotoxicity, and emergency seizure conditions such as status epilepticus. Expectedly, the molecular and system mechanisms responsible for epileptogenesis are not well defined or understood. To date, there is no approved therapy for the prevention of epilepsy. Epigenetic dysregulation, neuroinflammation, and neurodegeneration appear to trigger epileptogenesis. Targeted drugs are being identified that can truly prevent the development of epilepsy in at-risk people. The promising agents include rapamycin, COX-2 inhibitors, TRK inhibitors, epigenetic modulators, JAK-STAT inhibitors, and neurosteroids. Recent evidence suggests that neurosteroids may play a role in modulating epileptogenesis. A number of promising drugs are under investigation for the prevention or modification of epileptogenesis to halt the development of epilepsy. Some drugs in development appear rational for preventing epilepsy because they target the initial trigger or related signaling pathways as the brain becomes progressively more prone to seizures. Additional research into the target validity and clinical investigation is essential to make new frontiers in curing epilepsy.
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Affiliation(s)
- Bryan L Clossen
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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Kinjo ER, Rodríguez PXR, Dos Santos BA, Higa GSV, Ferraz MSA, Schmeltzer C, Rüdiger S, Kihara AH. New Insights on Temporal Lobe Epilepsy Based on Plasticity-Related Network Changes and High-Order Statistics. Mol Neurobiol 2017; 55:3990-3998. [PMID: 28555345 DOI: 10.1007/s12035-017-0623-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 05/16/2017] [Indexed: 12/21/2022]
Abstract
Epilepsy is a disorder of the brain characterized by the predisposition to generate recurrent unprovoked seizures, which involves reshaping of neuronal circuitries based on intense neuronal activity. In this review, we first detailed the regulation of plasticity-associated genes, such as ARC, GAP-43, PSD-95, synapsin, and synaptophysin. Indeed, reshaping of neuronal connectivity after the primary, acute epileptogenesis event increases the excitability of the temporal lobe. Herein, we also discussed the heterogeneity of neuronal populations regarding the number of synaptic connections, which in the theoretical field is commonly referred as degree. Employing integrate-and-fire neuronal model, we determined that in addition to increased synaptic strength, degree correlations might play essential and unsuspected roles in the control of network activity. Indeed, assortativity, which can be described as a condition where high-degree correlations are observed, increases the excitability of neural networks. In this review, we summarized recent topics in the field, and data were discussed according to newly developed or unusual tools, as provided by mathematical graph analysis and high-order statistics. With this, we were able to present new foundations for the pathological activity observed in temporal lobe epilepsy.
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Affiliation(s)
- Erika Reime Kinjo
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Pedro Xavier Royero Rodríguez
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Bianca Araújo Dos Santos
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Mariana Sacrini Ayres Ferraz
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Christian Schmeltzer
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
- Institute of Physics, Humboldt University at Berlin, Berlin, Germany
| | - Sten Rüdiger
- Institute of Physics, Humboldt University at Berlin, Berlin, Germany
| | - Alexandre Hiroaki Kihara
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
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Soares JI, Valente MC, Andrade PA, Maia GH, Lukoyanov NV. Reorganization of the septohippocampal cholinergic fiber system in experimental epilepsy. J Comp Neurol 2017; 525:2690-2705. [PMID: 28472854 DOI: 10.1002/cne.24235] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 04/11/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022]
Abstract
The septohippocampal cholinergic neurotransmission has long been implicated in seizures, but little is known about the structural features of this projection system in epileptic brain. We evaluated the effects of experimental epilepsy on the areal density of cholinergic terminals (fiber varicosities) in the dentate gyrus. For this purpose, we used two distinct post-status epilepticus rat models, in which epilepsy was induced with injections of either kainic acid or pilocarpine. To visualize the cholinergic fibers, we used brain sections immunostained for the vesicular acetylcholine transporter. It was found that the density of cholinergic fiber varicosities was higher in epileptic rats versus control rats in the inner and outer zones of the dentate molecular layer, but it was reduced in the dentate hilus. We further evaluated the effects of kainate treatment on the total number, density, and soma volume of septal cholinergic cells, which were visualized in brain sections stained for either vesicular acetylcholine transporter or choline acetyltransferase (ChAT). Both the number of septal cells with cholinergic phenotype and their density were increased in epileptic rats when compared to control rats. The septal cells stained for vesicular acetylcholine transporter, but not for ChAT, have enlarged perikarya in epileptic rats. These results revealed previously unknown details of structural reorganization of the septohippocampal cholinergic system in experimental epilepsy, involving fiber sprouting into the dentate molecular layer and a parallel fiber retraction from the dentate hilus. We hypothesize that epilepsy-related neuroplasticity of septohippocampal cholinergic neurons is capable of increasing neuronal excitability of the dentate gyrus.
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Affiliation(s)
- Joana I Soares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Maria C Valente
- Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Pedro A Andrade
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal.,Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Gisela H Maia
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Nikolai V Lukoyanov
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
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42
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Mante PK, Adongo DW, Woode E. Anticonvulsant effects of antiaris toxicaria aqueous extract: investigation using animal models of temporal lobe epilepsy. BMC Res Notes 2017; 10:167. [PMID: 28446201 PMCID: PMC5406926 DOI: 10.1186/s13104-017-2488-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 04/20/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Antiaris toxicaria has previously shown anticonvulsant activity in acute animal models of epilepsy. The aqueous extract (AAE) was further investigated for activity in kindling with pentylenetetrazole and administration of pilocarpine and kainic acid which mimic temporal lobe epilepsy in various animal species. RESULTS ICR mice and Sprague-Dawley rats were pre-treated with AAE (200-800 mg kg-1) and convulsive episodes induced using pentylenetetrazole, pilocarpine and kainic acid. The potential of AAE to prevent or delay onset and alter duration of seizures were measured. In addition, damage to hippocampal cells was assessed in kainic acid-induced status epilepticus test. 800 mg kg-1 of the extract suppressed the kindled seizure significantly (P < 0.05) as did diazepam. AAE also produced significant effect (P < 0.01) on latency to first myoclonic jerks and on total duration of seizures. The latency to onset of wet dog shakes was increased significantly (P < 0.05) by AAE on kainic acid administration. Carbamazepine and Nifedipine (30 mg kg-1) also delayed the onset. Histopathological examination of brain sections showed no protective effect on hippocampal cells by AAE and nifedipine. Carbamazepine offered better preservation of hippocampal cells in the CA1, CA2 and CA3 regions. CONCLUSION Antiaris toxicaria may be effective in controlling temporal lobe seizures in rodents.
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Affiliation(s)
- Priscilla Kolibea Mante
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | | | - Eric Woode
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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43
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Shubina L, Aliev R, Kitchigina V. Endocannabinoid-dependent protection against kainic acid-induced long-term alteration of brain oscillations in guinea pigs. Brain Res 2017; 1661:1-14. [DOI: 10.1016/j.brainres.2017.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 01/12/2023]
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Christenson Wick Z, Leintz CH, Xamonthiene C, Huang BH, Krook-Magnuson E. Axonal sprouting in commissurally projecting parvalbumin-expressing interneurons. J Neurosci Res 2017; 95:2336-2344. [PMID: 28151564 DOI: 10.1002/jnr.24011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 12/01/2016] [Accepted: 12/08/2016] [Indexed: 01/20/2023]
Abstract
Previous research has shown that in vivo on-demand optogenetic stimulation of inhibitory interneurons expressing parvalbumin (PV) is sufficient to suppress seizures in a mouse model of temporal lobe epilepsy (TLE). Surprisingly, this intervention was capable of suppressing seizures when PV-expressing interneurons were stimulated ipsilateral or contralateral to the presumed seizure focus, raising the possibility of commissural inhibition in TLE. There are mixed reports regarding commissural PV interneuron projections in the healthy hippocampus, and it was previously unknown whether these connections would be maintained or modified following the network reorganization associated with TLE. Using retrograde labeling and viral vector technology in both sexes and the intrahippocampal kainate mouse model of TLE, we therefore examined these issues. Our results reveal that healthy controls possess a population of commissurally projecting hippocampal PV interneurons. Two weeks post kainate injection, we observed a slight, but not statistically significant decrease in retrogradely labeled PV interneurons in the hippocampus contralateral to kainate and tracer injection. By 6 months post kainate, however, there was a significant increase in retrogradely labeled PV interneurons, suggesting commissural inhibitory axonal sprouting. Using viral green fluorescent protein expression selectively in PV neurons, we demonstrated sprouting of commissural PV projections in the dentate gyrus of the kainate-injected hippocampus 6 months post kainate. These findings indicate that PV interneurons supply direct inhibition to the contralateral hippocampus and undergo sprouting in a mouse model of TLE. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Caara H Leintz
- Neuroscience Department, University of Minnesota, Minneapolis
| | | | - Bin H Huang
- Neuroscience Department, University of Minnesota, Minneapolis
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Natarajan G, Leibowitz JA, Zhou J, Zhao Y, McElroy JA, King MA, Ormerod BK, Carney PR. Adeno-associated viral vector-mediated preprosomatostatin expression suppresses induced seizures in kindled rats. Epilepsy Res 2017; 130:81-92. [PMID: 28167431 DOI: 10.1016/j.eplepsyres.2017.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/04/2016] [Accepted: 01/04/2017] [Indexed: 01/29/2023]
Abstract
Somatostatin is expressed widely in the hippocampus and notably in hilar GABAergic neurons that are vulnerable to seizure neuropathology in chronic temporal lobe epilepsy. We previously demonstrated that sustained bilateral preprosomatostatin (preproSST) expression in the hippocampus prevents the development of generalized seizures in the amygdala kindling model of temporal lobe epilepsy. Here we tested whether sustained preproSST expression is anticonvulsant in rats already kindled to high-grade seizures. Rats were kindled until they exhibited 3 consecutive Racine Grade 5 seizures before adeno-associated virus serotype 5 (AAV5) vector driving either eGFP (AAV5-CBa-eGFP) or preproSST and eGFP (AAV5-CBa-preproSST-eGFP) expression was injected bilaterally into the hippocampal dentate gyrus and CA1 region. Retested 3 weeks later, rats that received control vector (AAV5-CBa-eGFP) continued to exhibit high-grade seizures whereas 6/13 rats that received preproSST vector (AAV5-CBa-preproSST-eGFP) were seizure-free. Of these rats, 5/6 remained seizure-free after repeated stimulation sessions and when the stimulation current was increased. These results suggest that vector-mediated expression of preproSST may be a viable therapeutic strategy for temporal lobe epilepsy.
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Affiliation(s)
- Gowri Natarajan
- Wilder Center of Excellence for Epilepsy Research, University of Florida, Gainesville, FL 32611, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA; Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA; Department of Neurology, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Jeffrey A Leibowitz
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Junli Zhou
- Wilder Center of Excellence for Epilepsy Research, University of Florida, Gainesville, FL 32611, USA; Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA; Department of Neurology, University of Florida, Gainesville, FL 32611, USA
| | - Yang Zhao
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32611, USA
| | - Jessica A McElroy
- Wilder Center of Excellence for Epilepsy Research, University of Florida, Gainesville, FL 32611, USA; Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA
| | - Michael A King
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA; Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32611, USA; NF/SG VA Medical Center, University of Florida, Gainesville, FL 32611, USA
| | - Brandi K Ormerod
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Paul R Carney
- Wilder Center of Excellence for Epilepsy Research, University of Florida, Gainesville, FL 32611, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA; Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA; Department of Neurology, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA.
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Vorobyov V, Bobkova N. Intracerebral interplay and neurotransmitter systems involvement in animal models of neurodegenerative disorders: EEG approach expectations. Neural Regen Res 2017; 12:66-67. [PMID: 28250746 PMCID: PMC5319240 DOI: 10.4103/1673-5374.198981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Vasily Vorobyov
- Institute of Cell Biophysics, Russian Academy of Sciences, Moscow Region, Russia
| | - Natalia Bobkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Moscow Region, Russia
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47
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Sailor KA, Schinder AF, Lledo PM. Adult neurogenesis beyond the niche: its potential for driving brain plasticity. Curr Opin Neurobiol 2016; 42:111-117. [PMID: 28040643 DOI: 10.1016/j.conb.2016.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 12/14/2022]
Abstract
Adult neurogenesis emerges as a tremendous form of plasticity with the continuous addition and loss of neurons in the adult brain. It is unclear how preexisting adult circuits generated during development are capable of modifying existing connections to accommodate the thousands of new synapses formed and exchanged each day. Here we first make parallels with sensory deprivation studies and its ability to induce preexisting non-neurogenic adult circuits to undergo massive reorganization. We then review recent studies that show high structural and synaptic plasticity in circuits directly connected to adult-born neurons. Finally, we propose future directions in the field to decipher how host circuits can accommodate new neuron integration and to determine the impact of adult neurogenesis on global brain plasticity.
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Affiliation(s)
- Kurt A Sailor
- Laboratory for Perception and Memory, Pasteur Institute, F-75015 Paris, France; Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (UMR3571), F-75015 Paris, France
| | - Alejandro F Schinder
- Laboratory of Neuronal Plasticity, Leloir Institute (IIBBA - CONICET), Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - Pierre-Marie Lledo
- Laboratory for Perception and Memory, Pasteur Institute, F-75015 Paris, France; Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (UMR3571), F-75015 Paris, France.
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48
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Delahaye-Duriez A, Srivastava P, Shkura K, Langley SR, Laaniste L, Moreno-Moral A, Danis B, Mazzuferi M, Foerch P, Gazina EV, Richards K, Petrou S, Kaminski RM, Petretto E, Johnson MR. Rare and common epilepsies converge on a shared gene regulatory network providing opportunities for novel antiepileptic drug discovery. Genome Biol 2016; 17:245. [PMID: 27955713 PMCID: PMC5154105 DOI: 10.1186/s13059-016-1097-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/02/2016] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The relationship between monogenic and polygenic forms of epilepsy is poorly understood and the extent to which the genetic and acquired epilepsies share common pathways is unclear. Here, we use an integrated systems-level analysis of brain gene expression data to identify molecular networks disrupted in epilepsy. RESULTS We identified a co-expression network of 320 genes (M30), which is significantly enriched for non-synonymous de novo mutations ascertained from patients with monogenic epilepsy and for common variants associated with polygenic epilepsy. The genes in the M30 network are expressed widely in the human brain under tight developmental control and encode physically interacting proteins involved in synaptic processes. The most highly connected proteins within the M30 network were preferentially disrupted by deleterious de novo mutations for monogenic epilepsy, in line with the centrality-lethality hypothesis. Analysis of M30 expression revealed consistent downregulation in the epileptic brain in heterogeneous forms of epilepsy including human temporal lobe epilepsy, a mouse model of acquired temporal lobe epilepsy, and a mouse model of monogenic Dravet (SCN1A) disease. These results suggest functional disruption of M30 via gene mutation or altered expression as a convergent mechanism regulating susceptibility to epilepsy broadly. Using the large collection of drug-induced gene expression data from Connectivity Map, several drugs were predicted to preferentially restore the downregulation of M30 in epilepsy toward health, most notably valproic acid, whose effect on M30 expression was replicated in neurons. CONCLUSIONS Taken together, our results suggest targeting the expression of M30 as a potential new therapeutic strategy in epilepsy.
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Affiliation(s)
- Andree Delahaye-Duriez
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK.
- MRC Clinical Sciences Centre, Imperial College London, London, UK.
- Université Paris 13, Sorbonne Paris Cité, UFR de Santé, Médecine et Biologie Humaine, Paris, France.
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
| | - Prashant Srivastava
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK
| | - Kirill Shkura
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK
| | - Sarah R Langley
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK
- Duke-NUS Medical School, 8 College Road, 169857, Singapore, Republic of Singapore
| | - Liisi Laaniste
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK
| | - Aida Moreno-Moral
- MRC Clinical Sciences Centre, Imperial College London, London, UK
- Duke-NUS Medical School, 8 College Road, 169857, Singapore, Republic of Singapore
| | - Bénédicte Danis
- Neuroscience TA, UCB Pharma, S.A, Allée de la Recherche, 60, 1070, Brussels, Belgium
| | - Manuela Mazzuferi
- Neuroscience TA, UCB Pharma, S.A, Allée de la Recherche, 60, 1070, Brussels, Belgium
| | - Patrik Foerch
- Neuroscience TA, UCB Pharma, S.A, Allée de la Recherche, 60, 1070, Brussels, Belgium
| | - Elena V Gazina
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Kay Richards
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia
- The Centre for Neural Engineering, The Department of Electrical Engineering, The University of Melbourne, Parkville, Victoria, 3052, Australia
- The Australian Research Council Centre of Excellence for Integrative Brain Function, Parkville, Victoria, 3052, Australia
| | - Rafal M Kaminski
- Neuroscience TA, UCB Pharma, S.A, Allée de la Recherche, 60, 1070, Brussels, Belgium
| | - Enrico Petretto
- MRC Clinical Sciences Centre, Imperial College London, London, UK.
- Duke-NUS Medical School, 8 College Road, 169857, Singapore, Republic of Singapore.
| | - Michael R Johnson
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, UK.
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49
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Sadeghi L, Rizvanov AA, Salafutdinov II, Dabirmanesh B, Sayyah M, Fathollahi Y, Khajeh K. Hippocampal asymmetry: differences in the left and right hippocampus proteome in the rat model of temporal lobe epilepsy. J Proteomics 2016; 154:22-29. [PMID: 27932302 DOI: 10.1016/j.jprot.2016.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/24/2016] [Accepted: 11/30/2016] [Indexed: 01/08/2023]
Abstract
The hippocampus is a complex brain structure and undergoes severe sclerosis and gliosis in temporal lobe epilepsy (TLE) as the most common type of epilepsy. The key features of the TLE may be reported in chronic animal models of epilepsy, such as pilocarpine model. Therefore, the current study was conducted in a rat pilocarpine model of acquired epilepsy. Two-dimensional gel electrophoresis based proteomic technique was used to compare the proteome map of the left and right hippocampus in both control and epileptic rats. Generally, 95 differentially expressed spots out of 1300 spots were identified in the hippocampus proteome using MALDI-TOF-TOF/MS. Within identified proteins, some showed asymmetric expression related to the mechanisms underlying TLE imposed by pilocarpine. Assessment of lateralization at the molecular level demonstrated that expression of proteins involved in dopamine synthesis was significantly more in the right hippocampus than the left one. In the epileptic model, reduction in dopamine pathway proteins was accompanied by an increase in the expression of proteins involved in polyamine synthesis, referring to a new regulating mechanism. Our results revealed changes in the laterality of protein expression due to pilocarpine-induced status epilepticus that could present some new proteins as potential candidates for antiepileptic drug design. BIOLOGICAL SIGNIFICANCE In the current study, two-dimensional gel electrophoresis (2-DE) based proteomic technique was used to profile changes in the left and right hippocampus proteome after pilocarpine induced status epilepticus. Spots of proteome maps for two hemispheres were excised and identified with MALDI-TOF-TOF/MS. Analysis of proteome map of the left and right hippocampus revealed a lateralization at the molecular level, in which the expression of proteins involved in dopamine synthesis and release were significantly more in right hippocampi than the left ones in the normal rats. Also, the expression of proteins involved in polyamine synthesis significantly increased in epileptic hippocampus (considerably higher in right hippocampi), whilst the proteins which included in dopamine pathways were decreased. Our results revealed changes in the laterality of protein expression due to pilocarpine-induced status epilepticus that could present some new proteins as potential candidates for antiepileptic drug design.
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Affiliation(s)
- Leila Sadeghi
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran
| | | | | | - Bahareh Dabirmanesh
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Sayyah
- Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Medical Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Khosro Khajeh
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran.
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50
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Chakraborty TR, Cohen J, Yohanan D, Alicea E, Weeks BS, Chakraborty S. Estrogen is neuroprotective against hypoglycemic injury in murine N38 hypothalamic cells. Mol Med Rep 2016; 14:5677-5684. [PMID: 27878271 DOI: 10.3892/mmr.2016.5952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/25/2016] [Indexed: 11/05/2022] Open
Abstract
Estrogen (E2) has been demonstrated to possess protective effects from hypoglycemic toxicity, particularly in the pancreas. In the central nervous system, several brain regions, such as the hypothalamus, are highly vulnerable to hypoglycemic injuries that may lead to seizures, coma, and mortality. The present study performed a novel in vitro assay of hypoglycemic injury to hypothalamic cells, and is the first study, to the best of our knowledge, to demonstrate that E2 protects hypothalamic cells from hypoglycemic toxicity. The toxic effects of hypoglycemia on hypothalamic cells in vitro was determined by performing cell counts, together with MTT and lactate dehydrogenase assays, using the N38 murine hypothalamic cell line. Following 24 and 48 h in hypoglycemic conditions, a 60 and 75% reduction in cell number and mitochondrial function was observed, which reached 80 and ~100% by 72 and 96 h, respectively. E2 treatment prevented the hypoglycemia‑induced loss in cell number and mitochondrial toxicity at 24 and 48 h. However at 72 and 96 h of hypoglycemic conditions, the neuroprotective effects of E2 on cell number or mitochondrial function was not significant or not present at all. In order to determine whether E2 exerted its effects through the AKT signaling pathway, the expression of proline‑rich AKT substrate of 40 kDa (PRAS40) was analyzed. No alterations in PRAS40 expression were observed when N38 cells were exposed to hypoglycemic shock. From the biochemical and molecular data obtained, the authors speculated that E2 exhibits neuroprotective effects against hypoglycemic shock in hypothalamic cells, which dissipates with time. Despite demonstrating no significant effect on total AKT/PRS40 activity, it is possible that E2 may mediate these neuroprotective effects by upregulating the phosphorylated‑AKT/pPRAS40 signaling pathway. The present study presented, to the best of our knowledge, the first in vitro model for hypoglycemic toxicity to hypothalamic cells, and provided evidence to suggest that E2 may protect hypothalamic cells from the damaging effects of hypoglycemia.
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Affiliation(s)
| | - Joshua Cohen
- Department of Biology, Adelphi University, Garden City, NY 11530, USA
| | - Darien Yohanan
- Department of Biology, Adelphi University, Garden City, NY 11530, USA
| | - Eilliut Alicea
- Department of Biology, Adelphi University, Garden City, NY 11530, USA
| | - Benjamin S Weeks
- Department of Biology, Adelphi University, Garden City, NY 11530, USA
| | - Sanjoy Chakraborty
- Department of Biological Sciences, New York City College of Technology, City University of New York, New York, NY 11201, USA
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