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Sint Jago SC, Bahabry R, Schreiber AM, Homola J, Ngyuen T, Meijia F, Allendorfer JB, Lubin FD. Aerobic exercise alters DNA hydroxymethylation levels in an experimental rodent model of temporal lobe epilepsy. Epilepsy Behav Rep 2023; 25:100642. [PMID: 38323091 PMCID: PMC10844942 DOI: 10.1016/j.ebr.2023.100642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/24/2023] [Accepted: 12/26/2023] [Indexed: 02/08/2024] Open
Abstract
The therapeutic potential of aerobic exercise in mitigating seizures and cognitive issues in temporal lobe epilepsy (TLE) is recognized, yet the underlying mechanisms are not well understood. Using a rodent TLE model induced by Kainic acid (KA), we investigated the impact of a single bout of exercise (i.e., acute) or 4 weeks of aerobic exercise (i.e., chronic). Blood was processed for epilepsy-associated serum markers, and DNA methylation (DNAme), and hippocampal area CA3 was assessed for gene expression levels for DNAme-associated enzymes. While acute aerobic exercise did not alter serum Brain-Derived Neurotrophic Factor (BDNF) or Interleukin-6 (IL-6), chronic exercise resulted in an exercise-specific decrease in serum BDNF and an increase in serum IL-6 levels in epileptic rats. Additionally, whole blood DNAme levels, specifically 5-hydroxymethylcytosine (5-hmC), decreased in epileptic animals following chronic exercise. Hippocampal CA3 5-hmC levels and ten-eleven translocation protein (TET1) expression mirrored these changes. Furthermore, immunohistochemistry analysis revealed that most 5-hmC changes in response to chronic exercise were neuron-specific within area CA3 of the hippocampus. Together, these findings suggest that DNAme mechanisms in the rodent model of TLE are responsive to chronic aerobic exercise, with emphasis on neuronal 5-hmC DNAme in the epileptic hippocampus.
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Affiliation(s)
| | - Rudhab Bahabry
- Department of Neurobiology, University of Alabama at Birmingham, United States
| | | | - Julia Homola
- Department of Neurobiology, University of Alabama at Birmingham, United States
| | - Tram Ngyuen
- Department of Neurobiology, University of Alabama at Birmingham, United States
| | - Fernando Meijia
- Department of Neurobiology, University of Alabama at Birmingham, United States
| | - Jane B. Allendorfer
- Department of Neurobiology, University of Alabama at Birmingham, United States
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Farah D. Lubin
- Department of Neurobiology, University of Alabama at Birmingham, United States
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Varlamova EG, Borisova EV, Evstratova YA, Newman AG, Kuldaeva VP, Gavrish MS, Kondakova EV, Tarabykin VS, Babaev AA, Turovsky EA. Socrates: A Novel N-Ethyl-N-nitrosourea-Induced Mouse Mutant with Audiogenic Epilepsy. Int J Mol Sci 2023; 24:17104. [PMID: 38069426 PMCID: PMC10707124 DOI: 10.3390/ijms242317104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Epilepsy is one of the common neurological diseases that affects not only adults but also infants and children. Because epilepsy has been studied for a long time, there are several pharmacologically effective anticonvulsants, which, however, are not suitable as therapy for all patients. The genesis of epilepsy has been extensively investigated in terms of its occurrence after injury and as a concomitant disease with various brain diseases, such as tumors, ischemic events, etc. However, in the last decades, there are multiple reports that both genetic and epigenetic factors play an important role in epileptogenesis. Therefore, there is a need for further identification of genes and loci that can be associated with higher susceptibility to epileptic seizures. Use of mouse knockout models of epileptogenesis is very informative, but it has its limitations. One of them is due to the fact that complete deletion of a gene is not, in many cases, similar to human epilepsy-associated syndromes. Another approach to generating mouse models of epilepsy is N-Ethyl-N-nitrosourea (ENU)-directed mutagenesis. Recently, using this approach, we generated a novel mouse strain, soc (socrates, formerly s8-3), with epileptiform activity. Using molecular biology methods, calcium neuroimaging, and immunocytochemistry, we were able to characterize the strain. Neurons isolated from soc mutant brains retain the ability to differentiate in vitro and form a network. However, soc mutant neurons are characterized by increased spontaneous excitation activity. They also demonstrate a high degree of Ca2+ activity compared to WT neurons. Additionally, they show increased expression of NMDA receptors, decreased expression of the Ca2+-conducting GluA2 subunit of AMPA receptors, suppressed expression of phosphoinositol 3-kinase, and BK channels of the cytoplasmic membrane involved in protection against epileptogenesis. During embryonic and postnatal development, the expression of several genes encoding ion channels is downregulated in vivo, as well. Our data indicate that soc mutation causes a disruption of the excitation-inhibition balance in the brain, and it can serve as a mouse model of epilepsy.
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Affiliation(s)
- Elena G. Varlamova
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia;
| | - Ekaterina V. Borisova
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Yuliya A. Evstratova
- Federal State Budgetary Educational Institution of Higher Education “MIREA—Russian Technological University”, 78, Vernadskogo Ave., 119454 Moscow, Russia;
| | - Andrew G. Newman
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
| | - Vera P. Kuldaeva
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Maria S. Gavrish
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Elena V. Kondakova
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Victor S. Tarabykin
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Alexey A. Babaev
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Egor A. Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia;
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
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Kang W, Ju C, Joo J, Lee J, Shon YM, Park SM. Closed-loop direct control of seizure focus in a rodent model of temporal lobe epilepsy via localized electric fields applied sequentially. Nat Commun 2022; 13:7805. [PMID: 36528681 PMCID: PMC9759546 DOI: 10.1038/s41467-022-35540-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Direct electrical stimulation of the seizure focus can achieve the early termination of epileptic oscillations. However, direct intervention of the hippocampus, the most prevalent seizure focus in temporal lobe epilepsy is thought to be not practicable due to its large size and elongated shape. Here, in a rat model, we report a sequential narrow-field stimulation method for terminating seizures, while focusing stimulus energy at the spatially extensive hippocampal structure. The effects and regional specificity of this method were demonstrated via electrophysiological and biological responses. Our proposed modality demonstrates spatiotemporal preciseness and selectiveness for modulating the pathological target region which may have potential for further investigation as a therapeutic approach.
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Affiliation(s)
- Wonok Kang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Chanyang Ju
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Jaesoon Joo
- Biomedical Engineering Research Center, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, South Korea
| | - Jiho Lee
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Young-Min Shon
- Biomedical Engineering Research Center, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, South Korea.
- Department of Neurology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, Republic of Korea.
| | - Sung-Min Park
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Electrical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Institute of Convergence Science, Yonsei University, Seoul, 03722, Republic of Korea.
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Early death in a mouse model of Alzheimer's disease exacerbated by microglial loss of TAM receptor signaling. Proc Natl Acad Sci U S A 2022; 119:e2204306119. [PMID: 36191221 PMCID: PMC9564325 DOI: 10.1073/pnas.2204306119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recurrent seizure is a common comorbidity in early-stage Alzheimer's disease (AD) and may contribute to AD pathogenesis and cognitive decline. Similarly, many mouse models of Alzheimer's disease that overproduce amyloid beta are prone to epileptiform seizures that may result in early sudden death. We studied one such model, designated APP/PS1, and found that mutation of the TAM receptor tyrosine kinase (RTK) Mer or its ligand Gas6 greatly exacerbated early death. Lethality was tied to violent seizures that appeared to initiate in the dentate gyrus (DG) of the hippocampus, where Mer plays an essential role in the microglial phagocytosis of both apoptotic and newborn cells normally generated during adult neurogenesis. We found that newborn DG neurons and excitatory synapses between the DG and the cornu ammonis field 3 (CA3) field of the hippocampus were increased in TAM-deficient mice, and that premature death and adult neurogenesis in these mice were coincident. In contrast, the incidence of lethal seizures and the deposition of dense-core amyloid plaques were strongly anticorrelated. Together, these results argue that TAM-mediated phagocytosis sculpts synaptic connectivity in the hippocampus, and that seizure-inducing amyloid beta polymers are present prior to the formation of dense-core plaques.
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Chakraborty S, Parayil R, Mishra S, Nongthomba U, Clement JP. Epilepsy Characteristics in Neurodevelopmental Disorders: Research from Patient Cohorts and Animal Models Focusing on Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms231810807. [PMID: 36142719 PMCID: PMC9501968 DOI: 10.3390/ijms231810807] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
Epilepsy, a heterogeneous group of brain-related diseases, has continued to significantly burden society and families. Epilepsy comorbid with neurodevelopmental disorders (NDDs) is believed to occur due to multifaceted pathophysiological mechanisms involving disruptions in the excitation and inhibition (E/I) balance impeding widespread functional neuronal circuitry. Although the field has received much attention from the scientific community recently, the research has not yet translated into actionable therapeutics to completely cure epilepsy, particularly those comorbid with NDDs. In this review, we sought to elucidate the basic causes underlying epilepsy as well as those contributing to the association of epilepsy with NDDs. Comprehensive emphasis is put on some key neurodevelopmental genes implicated in epilepsy, such as MeCP2, SYNGAP1, FMR1, SHANK1-3 and TSC1, along with a few others, and the main electrophysiological and behavioral deficits are highlighted. For these genes, the progress made in developing appropriate and valid rodent models to accelerate basic research is also detailed. Further, we discuss the recent development in the therapeutic management of epilepsy and provide a briefing on the challenges and caveats in identifying and testing species-specific epilepsy models.
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Affiliation(s)
- Sukanya Chakraborty
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Rrejusha Parayil
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Shefali Mishra
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - Upendra Nongthomba
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Correspondence: ; Tel.: +91-08-2208-2613
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Taniguchi S, Stolz JR, Swanson GT. The Antiseizure Drug Perampanel Is a Subunit-Selective Negative Allosteric Modulator of Kainate Receptors. J Neurosci 2022; 42:5499-5509. [PMID: 35654603 PMCID: PMC9295835 DOI: 10.1523/jneurosci.2397-21.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/27/2022] [Accepted: 05/24/2022] [Indexed: 01/16/2023] Open
Abstract
Perampanel (PMP) is a third-generation antiseizure drug reported to be a potent and selective noncompetitive negative allosteric modulator of one subfamily of ionotropic glutamate receptor (iGluR), the α-amino-3-hydroxy-S-methylisoxazole-4-propionic acid receptors (AMPARs). However, the recent structural resolution of AMPARs in complex with PMP revealed that its binding pocket is formed from residues that are largely conserved in two members of another family of iGluRs, the GluK4 and GluK5 kainate receptor (KAR) subunits. We show here that PMP inhibits both recombinant and neuronal KARs, contrary to the previous reports, and that the negative allosteric modulator (NAM) activity requires GluK5 subunits to be channel constituents. PMP inhibited heteromeric GluK1/GluK5 and GluK2/GluK5 KARs at IC50 values comparable to that for AMPA receptors but was much less potent on homomeric GluK1 or GluK2 KARs. The auxiliary subunits Neto1 or Neto2 also made GluK2-containing KARs more sensitive to inhibition. Finally, PMP inhibited mouse neuronal KARs containing GluK5 subunits and Neto proteins in nociceptive dorsal root ganglia neurons and hippocampal mossy fiber-CA3 pyramidal neuron synapses. These data suggest that clinical actions of PMP could arise from differential inhibition of AMPAR or KAR signaling and that more selective drugs might maintain antiseizure efficacy while reducing adverse effects.SIGNIFICANCE STATEMENT PMP is a regulatory approved antiseizure drug used for refractory partial-onset and generalized tonic-clonic seizures that acts as a selective negative allosteric modulator of AMPARs. Here, we demonstrate that PMP inhibits KARs, a second family of ionotropic glutamate receptors, in addition to AMPARs. NAM activity on KARs required GluK5 subunits or Neto auxiliary subunits as channel constituents. KAR inhibition, therefore, could contribute to PMP antiseizure action or the adverse effects that are significant with this drug. Drug discovery aimed at more selective allosteric modulators that discriminate between AMPARs and KARs could yield next-generation drugs with improved therapeutic profiles for treatment of epilepsy.
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Affiliation(s)
- Sakiko Taniguchi
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Jacob R Stolz
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Geoffrey T Swanson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Zhou F, Ebea P, Mutai E, Wang H, Sukreet S, Navazesh S, Dogan H, Li W, Cui J, Ji P, Ramirez DMO, Zempleni J. Small Extracellular Vesicles in Milk Cross the Blood-Brain Barrier in Murine Cerebral Cortex Endothelial Cells and Promote Dendritic Complexity in the Hippocampus and Brain Function in C57BL/6J Mice. Front Nutr 2022; 9:838543. [PMID: 35600828 PMCID: PMC9121399 DOI: 10.3389/fnut.2022.838543] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/29/2022] [Indexed: 12/12/2022] Open
Abstract
Human milk contains large amounts of small extracellular vesicles (sEVs) and their microRNA cargos, whereas infant formulas contain only trace amounts of sEVs and microRNAs. We assessed the transport of sEVs across the blood-brain barrier (BBB) and sEV accumulation in distinct regions of the brain in brain endothelial cells and suckling mice. We further assessed sEV-dependent gene expression profiles and effects on the dendritic complexity of hippocampal granule cells and phenotypes of EV depletion in neonate, juvenile and adult mice. The transfer of sEVs across the BBB was assessed by using fluorophore-labeled bovine sEVs in brain endothelial bEnd.3 monolayers and dual chamber systems, and in wild-type newborn pups fostered to sEV and cargo tracking (ECT) dams that express sEVs labeled with a CD63-eGFP fusion protein for subsequent analysis by serial two-photon tomography and staining with anti-eGFP antibodies. Effects of EVs on gene expression and dendritic architecture of granule cells was analyzed in hippocampi from juvenile mice fed sEV and RNA-depleted (ERD) and sEV and RNA-sufficient (ERS) diets by using RNA-sequencing analysis and Golgi-Cox staining followed by integrated neuronal tracing and morphological analysis of neuronal dendrites, respectively. Spatial learning and severity of kainic acid-induced seizures were assessed in mice fed ERD and ERS diets. bEnd.3 cells internalized sEVs by using a saturable transport mechanism and secreted miR-34a across the basal membrane. sEVs penetrated the entire brain in fostering experiments; major regions of accumulation included the hippocampus, cortex and cerebellum. Two hundred ninety-five genes were differentially expressed in hippocampi from mice fed ERD and ERS diets; high-confidence gene networks included pathways implicated in axon guidance and calcium signaling. Juvenile pups fed the ERD diet had reduced dendritic complexity of dentate granule cells in the hippocampus, scored nine-fold lower in the Barnes maze test of spatial learning and memory, and the severity of seizures was 5-fold higher following kainic acid administration in adult mice fed the ERD diet compared to mice fed the ERS diet. We conclude that sEVs cross the BBB and contribute toward optimal neuronal development, spatial learning and memory, and resistance to kainic acid-induced seizures in mice.
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Affiliation(s)
- Fang Zhou
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Pearl Ebea
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Ezra Mutai
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Haichuan Wang
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Sonal Sukreet
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Shya Navazesh
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Haluk Dogan
- School of Computing, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Wenhao Li
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Juan Cui
- School of Computing, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Peng Ji
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Denise M. O. Ramirez
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Janos Zempleni
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
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Gulino M, Santos SD, Pêgo AP. Biocompatibility of Platinum Nanoparticles in Brain ex vivo Models in Physiological and Pathological Conditions. Front Neurosci 2022; 15:787518. [PMID: 34975386 PMCID: PMC8714788 DOI: 10.3389/fnins.2021.787518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/26/2021] [Indexed: 12/22/2022] Open
Abstract
Platinum nanoparticles (PtNPs) have unique physico-chemical properties that led to their use in many branches of medicine. Recently, PtNPs gathered growing interest as delivery vectors for drugs, biosensors and as surface coating on chronically implanted biomedical devices for improving electrochemical properties. However, there are contradictory statements about their biocompatibility and impact on target organs such as the brain tissue, where these NPs are finding many applications. Furthermore, many of the reported studies are conducted in homeostasis conditions and, consequently, neglect the impact of the pathologic conditions on the tissue response. To expand our knowledge on the effects of PtNPs on neuronal and glial cells, we investigated the acute effects of monodisperse sodium citrate-coated PtNPs on rat organotypic hippocampal cultures in physiological or neuronal excitotoxic conditions induced by kainic acid (KA). The cellular responses of the PtNPs were evaluated through cytotoxic assays and confocal microscopy analysis. To mimic a pathologic scenario, 7-day organotypic hippocampal cultures were exposed to KA for 24 h. Subsequently, PtNPs were added to each slice. We show that incubation of the slices with PtNPs for 24 h, does not severely impact cell viability in normal conditions, with no significant differences when comparing the dentate gyrus (DG), as well as CA3 and CA1 pyramidal cell layers. Such effects are not exacerbated in KA-treated slices, where the presence of PtNPs does not cause additional neuronal propidium iodide (PI) uptake in CA3 and CA1 pyramidal cell layers. However, PtNPs cause microglial cell activation and morphological alterations in CA3 and DG regions indicating the establishment of an inflammatory reaction. Morphological analysis revealed that microglia acquire activated ameboid morphology with loss of ramifications, as a result of their response to PtNPs contact. Surprisingly, this effect is not increased in pathological conditions. Taken together, these results show that PtNPs cause microglia alterations in short-term studies. Additionally, there is no worsening of the tissue response in a neuropathological induced scenario. This work highlights the need of further research to allow for the safe use of PtNPs. Also, it supports the demand of the development of novel and more biocompatible NPs to be applied in the brain.
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Affiliation(s)
- Maurizio Gulino
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Sofia Duque Santos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Characterization of metabolic activity induced by kainic acid in adult rat whole brain at the early stage: A 18FDG-PET study. Brain Res 2021; 1769:147621. [PMID: 34403661 DOI: 10.1016/j.brainres.2021.147621] [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: 04/21/2021] [Revised: 07/08/2021] [Accepted: 08/10/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Brain metabolic processes are not fully characterized in the kainic acid (KA)-induced Status Epilepticus (KASE). Thus, we evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as an experimental strategy to evaluate in vivo, in a non-invasive way, the glucose consumption in several brain regions, in a semi-quantitative study to compare and to correlate with data from electroencephalography and histology studies. METHODS Sixteen male Wistar rats underwent FDG-PET scans at basal state and after KA injection. FDG-PET images were normalized to an MRI-based atlas and segmented to locate regions. Standardized uptake values (SUV) were obtained at several time points. EEGs and cell viability by histological analysis, were also evaluated. RESULTS FDG-PET data showed changes in regions such as: amygdala, hippocampus, accumbens, entorhinal cortex, motor cortex and hypothalamus. Remarkably, hippocampal hypermetabolism was found (mean SUV = 2.66 ± 0.057) 2 h after KA administration, while hypometabolism at 24 h (mean SUV = 1.83 ± 0.056) vs basal values (mean SUV = 2.19 ± 0.057). EEG showed increased spectral power values 2 h post-KA administration. Hippocampal viable-cell counting 24 h after KA was decreased, while Fluoro-Jade B-positive cells were increased, as compared to control rats, coinciding with the hypometabolism detected in the same region by semi-quantitative FDG-PET at 24 h after KASE. CONCLUSIONS PET is suitable to measure metabolic brain changes in the rat model of status epilepticus induced by KA (KASE) at the first 24 h, compared to that of EEG; PET data may also be sensitive to cell viability.
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Kandasamy LC, Tsukamoto M, Banov V, Tsetsegee S, Nagasawa Y, Kato M, Matsumoto N, Takeda J, Itohara S, Ogawa S, Young LJ, Zhang Q. Limb-clasping, cognitive deficit and increased vulnerability to kainic acid-induced seizures in neuronal glycosylphosphatidylinositol deficiency mouse models. Hum Mol Genet 2021; 30:758-770. [PMID: 33607654 PMCID: PMC8161520 DOI: 10.1093/hmg/ddab052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 11/26/2022] Open
Abstract
Posttranslational modification of a protein with glycosylphosphatidylinositol (GPI) is a conserved mechanism exists in all eukaryotes. Thus far, >150 human GPI-anchored proteins have been discovered and ~30 enzymes have been reported to be involved in the biosynthesis and maturation of mammalian GPI. Phosphatidylinositol glycan biosynthesis class A protein (PIGA) catalyzes the very first step of GPI anchor biosynthesis. Patients carrying a mutation of the PIGA gene usually suffer from inherited glycosylphosphatidylinositol deficiency (IGD) with intractable epilepsy and intellectual developmental disorder. We generated three mouse models with PIGA deficits specifically in telencephalon excitatory neurons (Ex-M-cko), inhibitory neurons (In-M-cko) or thalamic neurons (Th-H-cko), respectively. Both Ex-M-cko and In-M-cko mice showed impaired long-term fear memory and were more susceptible to kainic acid-induced seizures. In addition, In-M-cko demonstrated a severe limb-clasping phenotype. Hippocampal synapse changes were observed in Ex-M-cko mice. Our Piga conditional knockout mouse models provide powerful tools to understand the cell-type specific mechanisms underlying inherited GPI deficiency and to test different therapeutic modalities.
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Affiliation(s)
- Lenin C Kandasamy
- Laboratory of Social Neural Networks, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Mina Tsukamoto
- Laboratory of Social Neural Networks, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Vitaliy Banov
- Laboratory for Behavioral Genetics, CBS, RIKEN, Wako 351-0198, Japan.,Institute of Neuroinformatics, University of Zürich, ETH Zürich, Zürich 8057, Switzerland
| | - Sambuu Tsetsegee
- Laboratory of Social Neural Networks, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Yutaro Nagasawa
- Laboratory of Social Neural Networks, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo 142-8555, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Junji Takeda
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | | | - Sonoko Ogawa
- Laboratory of Behavioral Neuroendocrinology, Faculty of Human Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Larry J Young
- Faculty of Human Sciences, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan.,Center for Translational Social Neuroscience, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta GA 30329, USA
| | - Qi Zhang
- Laboratory of Social Neural Networks, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan.,Laboratory for Behavioral Genetics, CBS, RIKEN, Wako 351-0198, Japan.,Faculty of Human Sciences, Center for Social Neural Networks, University of Tsukuba, Tsukuba 305-8577, Japan
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11
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Jang S, Yang E, Kim D, Kim H, Kim E. Clmp Regulates AMPA and Kainate Receptor Responses in the Neonatal Hippocampal CA3 and Kainate Seizure Susceptibility in Mice. Front Synaptic Neurosci 2021; 12:567075. [PMID: 33408624 PMCID: PMC7779639 DOI: 10.3389/fnsyn.2020.567075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/02/2020] [Indexed: 12/05/2022] Open
Abstract
Synaptic adhesion molecules regulate synapse development through trans-synaptic adhesion and assembly of diverse synaptic proteins. Many synaptic adhesion molecules positively regulate synapse development; some, however, exert negative regulation, although such cases are relatively rare. In addition, synaptic adhesion molecules regulate the amplitude of post-synaptic receptor responses, but whether adhesion molecules can regulate the kinetic properties of post-synaptic receptors remains unclear. Here we report that Clmp, a homophilic adhesion molecule of the Ig domain superfamily that is abundantly expressed in the brain, reaches peak expression at a neonatal stage (week 1) and associates with subunits of AMPA receptors (AMPARs) and kainate receptors (KARs). Clmp deletion in mice increased the frequency and amplitude of AMPAR-mediated miniature excitatory post-synaptic currents (mEPSCs) and the frequency, amplitude, and decay time constant of KAR-mediated mEPSCs in hippocampal CA3 neurons. Clmp deletion had minimal impacts on evoked excitatory synaptic currents at mossy fiber-CA3 synapses but increased extrasynaptic KAR, but not AMPAR, currents, suggesting that Clmp distinctly inhibits AMPAR and KAR responses. Behaviorally, Clmp deletion enhanced novel object recognition and susceptibility to kainate-induced seizures, without affecting contextual or auditory cued fear conditioning or pattern completion-based contextual fear conditioning. These results suggest that Clmp negatively regulates hippocampal excitatory synapse development and AMPAR and KAR responses in the neonatal hippocampal CA3 as well as object recognition and kainate seizure susceptibility in mice.
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Affiliation(s)
- Seil Jang
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, South Korea
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, South Korea
| | - Doyoun Kim
- Center for Drug Discovery Platform Research, Korea Research Institute of Chemical Technology (KRICT), Daejeon, South Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, South Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, South Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
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12
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Browne TJ, Hughes DI, Dayas CV, Callister RJ, Graham BA. Projection Neuron Axon Collaterals in the Dorsal Horn: Placing a New Player in Spinal Cord Pain Processing. Front Physiol 2020; 11:560802. [PMID: 33408637 PMCID: PMC7779806 DOI: 10.3389/fphys.2020.560802] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 11/26/2020] [Indexed: 11/13/2022] Open
Abstract
The pain experience depends on the relay of nociceptive signals from the spinal cord dorsal horn to higher brain centers. This function is ultimately achieved by the output of a small population of highly specialized neurons called projection neurons (PNs). Like output neurons in other central nervous system (CNS) regions, PNs are invested with a substantial axon collateral system that ramifies extensively within local circuits. These axon collaterals are widely distributed within and between spinal cord segments. Anatomical data on PN axon collaterals have existed since the time of Cajal, however, their function in spinal pain signaling remains unclear and is absent from current models of spinal pain processing. Despite these omissions, some insight on the potential role of PN axon collaterals can be drawn from axon collateral systems of principal or output neurons in other CNS regions, such as the hippocampus, amygdala, olfactory cortex, and ventral horn of the spinal cord. The connectivity and actions of axon collaterals in these systems have been well-defined and used to confirm crucial roles in memory, fear, olfaction, and movement control, respectively. We review this information here and propose a framework for characterizing PN axon collateral function in the dorsal horn. We highlight that experimental approaches traditionally used to delineate axon collateral function in other CNS regions are not easily applied to PNs because of their scarcity relative to spinal interneurons (INs), and the lack of cellular organization in the dorsal horn. Finally, we emphasize how the rapid development of techniques such as viral expression of optogenetic or chemogenetic probes can overcome these challenges and allow characterization of PN axon collateral function. Obtaining detailed information of this type is a necessary first step for incorporation of PN collateral system function into models of spinal sensory processing.
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Affiliation(s)
- Tyler J Browne
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute (HMRI), New Lambton Heights, NSW, Australia
| | - David I Hughes
- Institute of Neuroscience Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute (HMRI), New Lambton Heights, NSW, Australia
| | - Robert J Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute (HMRI), New Lambton Heights, NSW, Australia
| | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute (HMRI), New Lambton Heights, NSW, Australia
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13
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Tsai CM, Chang SF, Chang H. Transcranial photobiomodulation attenuates pentylenetetrazole-induced status epilepticus in peripubertal rats. JOURNAL OF BIOPHOTONICS 2020; 13:e202000095. [PMID: 32362066 DOI: 10.1002/jbio.202000095] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/25/2020] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
Convulsive status epilepticus is the most common neurological emergency in children. Transcranial photobiomodulation (tPBM) reverses elevated rodent neurotransmitters after status epilepticus (SE) yet whether tPBM can attenuate seizure behaviors remains unknown. Here, we applied near-infrared laser at wavelength 808 nm transcranially to peripubertal Sprague-Dawley rats prior to pentylenetetrazole (PTZ) injection. Hematoxylin-eosin, immunofluorescence (IF) staining with anti-parvalbumin (PV) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay after IF staining was performed. Behaviorally, tPBM attenuated the mean seizure score and reduced the incidence of SE and mortality. Histochemically, tPBM reduced dark neurons in the cortex, hippocampus, thalamus and hypothalamus, lessened the apoptotic ratio of parvalbumin-positive interneurons (PV-INs) and alleviated the aberrant extent of PV-positive unstained somata of PCs in the hippocampus. Conclusively, tPBM attenuated PTZ-induced seizures, SE and mortality in peripubertal rats and reduced PTZ-induced neuronal injury, apoptosis of PV-INs and preserved PV positive perisomatic inhibitory network in the hippocampus.
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Affiliation(s)
- Chung-Min Tsai
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shwu-Fen Chang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hsi Chang
- Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan
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14
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Tanioka M, Park WK, Shim I, Kim K, Choi S, Kim UJ, Lee KH, Hong SK, Lee BH. Neuroprotection from Excitotoxic Injury by Local Administration of Lipid Emulsion into the Brain of Rats. Int J Mol Sci 2020; 21:ijms21082706. [PMID: 32295117 PMCID: PMC7215821 DOI: 10.3390/ijms21082706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/10/2020] [Accepted: 04/12/2020] [Indexed: 01/10/2023] Open
Abstract
Lipid emulsion was recently shown to attenuate cell death caused by excitotoxic conditions in the heart. There are key similarities between neurons and cardiomyocytes, such as excitability and conductibility, which yield vulnerability to excitotoxic conditions. However, systematic investigations on the protective effects of lipid emulsion in the central nervous system are still lacking. This study aimed to determine the neuroprotective effects of lipid emulsion in an in vivo rat model of kainic acid-induced excitotoxicity through intrahippocampal microinjections. Kainic acid and/or lipid emulsion-injected rats were subjected to the passive avoidance test and elevated plus maze for behavioral assessment. Rats were sacrificed at 24 h and 72 h after kainic acid injections for molecular study, including immunoblotting and qPCR. Brains were also cryosectioned for morphological analysis through cresyl violet staining and Fluorojade-C staining. Anxiety and memory functions were significantly preserved in 1% lipid emulsion-treated rats. Lipid emulsion was dose-dependent on the protein expression of β-catenin and the phosphorylation of GSK3-β and Akt. Wnt1 mRNA expression was elevated in lipid emulsion-treated rats compared to the vehicle. Neurodegeneration was significantly reduced mainly in the CA1 region with increased cell survival. Our results suggest that lipid emulsion has neuroprotective effects against excitotoxic conditions in the brain and may provide new insight into its potential therapeutic utility.
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Affiliation(s)
- Motomasa Tanioka
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Wyun Kon Park
- Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea;
| | - Insop Shim
- Department of Physiology, School of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Kyeongmin Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Songyeon Choi
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Un Jeng Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
| | - Kyung Hee Lee
- Department of Dental Hygiene, Division of Health Science, Dongseo University, Busan 47011, Korea;
| | - Seong-Karp Hong
- Division of Biomedical Engineering, Mokwon University, Daejeon 35349, Korea;
| | - Bae Hwan Lee
- Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Korea; (M.T.); (K.K.); (S.C.); (U.J.K.)
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
- Correspondence: ; Tel.: + 82-2-2228-1711
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15
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Parato J, Shen H, Smith SS. α4βδ GABA A Receptors Trigger Synaptic Pruning and Reduce Dendritic Length of Female Mouse CA3 Hippocampal Pyramidal Cells at Puberty. Neuroscience 2019; 398:23-36. [PMID: 30496825 PMCID: PMC6411036 DOI: 10.1016/j.neuroscience.2018.11.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 01/24/2023]
Abstract
Synaptic pruning during adolescence is critical for optimal cognition. The CA3 hippocampus contains unique spine types and plays a pivotal role in pattern separation and seizure generation, where sex differences exist, but adolescent pruning has only been studied in the male. Thus, for the present study we assessed pruning of specific spine types in the CA3 hippocampus during adolescence and investigated a possible mechanism in the female mouse. To this end, we used Golgi-impregnated brains from pubertal (∼PND 35, assessed by vaginal opening) and post-pubertal (PND 56) mice. Spine density was assessed from z-stack (0.1-μm steps) images taken using a Nikon DS-U3 camera through a Nikon Eclipse Ci-L microscope and analyzed with NIS Elements. Spine density decreased significantly (P < 0.05) during adolescence, with 50-60% decreases in mushroom and stubby spine-types (P < 0.05, ∼PND35 vs. PND56) in non-proestrous mice. This was associated with decreases in kalirin-7, a spine protein which stabilizes the cytoskeleton and is required for spine maintenance. Because our previous findings suggest that pubertal increases in α4βδ GABAA receptors (GABARs) trigger pruning in CA1, we investigated their role in CA3. α4 expression in CA3 hippocampus increased 4-fold at puberty (P < 0.05), assessed by immunostaining and verified electrophysiologically by an increased response to gaboxadol (100 nM), which is selective for α4βδ. Knock-out of α4 prevented the pubertal decrease in kalirin-7 and synaptic pruning and also increased the dendritic length, demonstrating a functional link. These data suggest that pubertal α4βδ GABARs alter dendritic morphology and trigger pruning in female CA3 hippocampus.
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Affiliation(s)
- Julie Parato
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA; Program in Neural and Behavioral Science, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA
| | - Hui Shen
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA; School of Biomedical Engineering, Tianjin Medical University, No. 22 Qixiangtai Road, Heping District, Tianjin 300070, China
| | - Sheryl S Smith
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA; The Robert F. Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
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16
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Tanaka KZ, He H, Tomar A, Niisato K, Huang AJY, McHugh TJ. The hippocampal engram maps experience but not place. Science 2018; 361:392-397. [PMID: 30049878 DOI: 10.1126/science.aat5397] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/20/2018] [Indexed: 12/20/2022]
Abstract
Episodic memories are encoded by a sparse population of hippocampal neurons. In mice, optogenetic manipulation of this memory engram established that these neurons are indispensable and inducing for memory recall. However, little is known about their in vivo activity or precise role in memory. We found that during memory encoding, only a fraction of CA1 place cells function as engram neurons, distinguished by firing repetitive bursts paced at the theta frequency. During memory recall, these neurons remained highly context specific, yet demonstrated preferential remapping of their place fields. These data demonstrate a dissociation of precise spatial coding and contextual indexing by distinct hippocampal ensembles and suggest that the hippocampal engram serves as an index of memory content.
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Affiliation(s)
- Kazumasa Z Tanaka
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan.
| | - Hongshen He
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
| | - Anupratap Tomar
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan
| | - Kazue Niisato
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan
| | - Arthur J Y Huang
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan
| | - Thomas J McHugh
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wakoshi, Saitama, Japan. .,Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
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17
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Falcón-Moya R, Sihra TS, Rodríguez-Moreno A. Kainate Receptors: Role in Epilepsy. Front Mol Neurosci 2018; 11:217. [PMID: 29988380 PMCID: PMC6023982 DOI: 10.3389/fnmol.2018.00217] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/04/2018] [Indexed: 01/01/2023] Open
Abstract
Kainate (KA) is a potent neurotoxin that has been widely used experimentally to induce acute brain seizures and, after repetitive treatments, as a chronic model of temporal lobe epilepsy (TLE), with similar features to those observed in human patients with TLE. However, whether KA activates KA receptors (KARs) as an agonist to mediate the induction of acute seizures and/or the chronic phase of epilepsy, or whether epileptogenic effects of the neurotoxin are indirect and/or mediated by other types of receptors, has yet to be satisfactorily elucidated. Positing a direct involvement of KARs in acute seizures induction, as well as a direct pathophysiological role of KARs in the chronic phase of TLE, recent studies have examined the specific subunit compositions of KARs that might underly epileptogenesis. In the present mini-review, we discuss the use of KA as a convulsant in the experimental models of acute seizures of TLE, and consider the involvement of KARs, their subunit composition and the mode of action in KAR-mediated epilepsy. In acute models, evidence points to epileptogenesis being precipitated by an overall depression of interneuron GABAergic transmission mediated by GluK1 containing KARs. On glutamatergic principal cell in the hippocampus, GluK2-containing KARs regulate post-synaptic excitability and susceptibility to KA-mediated epileptogenesis. In chronic models, a role GluK2-containing KARs in the hippocampal CA3 region provokes limbic seizures. Also observed in the hippocampus, is a ‘reactive plasticity’, where MF sprouting is seen with target granule cells at aberrant synapses recruiting de novo GluR2/GluR5 heteromeric KARs. Finally, in human epilepsy and animal models, astrocytic expression of GluK1, 2, 4, and 5 is reported.
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Affiliation(s)
- Rafael Falcón-Moya
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, University Pablo de Olavide, Sevilla, Spain
| | - Talvinder S Sihra
- Department of Physiology, Pharmacology and Neuroscience, University College London, London, United Kingdom
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, University Pablo de Olavide, Sevilla, Spain
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18
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Exciting Times: New Advances Towards Understanding the Regulation and Roles of Kainate Receptors. Neurochem Res 2017; 44:572-584. [PMID: 29270706 PMCID: PMC6420428 DOI: 10.1007/s11064-017-2450-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/27/2017] [Accepted: 12/07/2017] [Indexed: 12/11/2022]
Abstract
Kainate receptors (KARs) are glutamate-gated ion channels that play fundamental roles in regulating neuronal excitability and network function in the brain. After being cloned in the 1990s, important progress has been made in understanding the mechanisms controlling the molecular and cellular properties of KARs, and the nature and extent of their regulation of wider neuronal activity. However, there have been significant recent advances towards understanding KAR trafficking through the secretory pathway, their precise synaptic positioning, and their roles in synaptic plasticity and disease. Here we provide an overview highlighting these new findings about the mechanisms controlling KARs and how KARs, in turn, regulate other proteins and pathways to influence synaptic function.
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19
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Boehringer R, Polygalov D, Huang AJ, Middleton SJ, Robert V, Wintzer ME, Piskorowski RA, Chevaleyre V, McHugh TJ. Chronic Loss of CA2 Transmission Leads to Hippocampal Hyperexcitability. Neuron 2017; 94:642-655.e9. [DOI: 10.1016/j.neuron.2017.04.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 02/16/2017] [Accepted: 04/06/2017] [Indexed: 12/22/2022]
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20
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Dutton SBB, Dutt K, Papale LA, Helmers S, Goldin AL, Escayg A. Early-life febrile seizures worsen adult phenotypes in Scn1a mutants. Exp Neurol 2017; 293:159-171. [PMID: 28373025 DOI: 10.1016/j.expneurol.2017.03.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 02/17/2017] [Accepted: 03/22/2017] [Indexed: 01/27/2023]
Abstract
Mutations in the voltage-gated sodium channel (VGSC) gene SCN1A, encoding the Nav1.1 channel, are responsible for a number of epilepsy disorders including genetic epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome (DS). Patients with SCN1A mutations often experience prolonged early-life febrile seizures (FSs), raising the possibility that these events may influence epileptogenesis and lead to more severe adult phenotypes. To test this hypothesis, we subjected 21-23-day-old mice expressing the human SCN1A GEFS+ mutation R1648H to prolonged hyperthermia, and then examined seizure and behavioral phenotypes during adulthood. We found that early-life FSs resulted in lower latencies to induced seizures, increased severity of spontaneous seizures, hyperactivity, and impairments in social behavior and recognition memory during adulthood. Biophysical analysis of brain slice preparations revealed an increase in epileptiform activity in CA3 pyramidal neurons along with increased action potential firing, providing a mechanistic basis for the observed worsening of adult phenotypes. These findings demonstrate the long-term negative impact of early-life FSs on disease outcomes. This has important implications for the clinical management of this patient population and highlights the need for therapeutic interventions that could ameliorate disease progression.
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Affiliation(s)
- Stacey B B Dutton
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA; Department of Biology, Agnes Scott College, Atlanta, GA 30030, USA
| | - Karoni Dutt
- Departments of Microbiology & Molecular Genetics and Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Ligia A Papale
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA
| | - Sandra Helmers
- Department of Neurology, Emory University, Atlanta, GA 30022, USA
| | - Alan L Goldin
- Departments of Microbiology & Molecular Genetics and Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA 30022, USA.
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