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Bahari F, Dzhala V, Balena T, Lillis KP, Staley KJ. Intraventricular haemorrhage in premature infants: the role of immature neuronal salt and water transport. Brain 2024; 147:3216-3233. [PMID: 38815055 PMCID: PMC11370806 DOI: 10.1093/brain/awae161] [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: 07/10/2023] [Revised: 04/25/2024] [Accepted: 04/28/2024] [Indexed: 06/01/2024] Open
Abstract
Intraventricular haemorrhage is a common complication of premature birth. Survivors are often left with cerebral palsy, intellectual disability and/or hydrocephalus. Animal models suggest that brain tissue shrinkage, with subsequent vascular stretch and tear, is an important step in the pathophysiology, but the cause of this shrinkage is unknown. Clinical risk factors for intraventricular haemorrhage are biomarkers of hypoxic-ischaemic stress, which causes mature neurons to swell. However, immature neuronal volume might shift in the opposite direction in these conditions. This is because immature neurons express the chloride, salt and water transporter NKCC1, which subserves regulatory volume increases in non-neural cells, whereas mature neurons express KCC2, which subserves regulatory volume decreases. When hypoxic-ischaemic conditions reduce active ion transport and increase the cytoplasmic membrane permeability, the effects of these transporters are diminished. Consequentially, mature neurons swell (cytotoxic oedema), whereas immature neurons might shrink. After hypoxic-ischaemic stress, in vivo and in vitro multi-photon imaging of perinatal transgenic mice demonstrated shrinkage of viable immature neurons, bulk tissue shrinkage and blood vessel displacement. Neuronal shrinkage was correlated with age-dependent membrane salt and water transporter expression using immunohistochemistry. Shrinkage of immature neurons was prevented by prior genetic or pharmacological inhibition of NKCC1 transport. These findings open new avenues of investigation for the detection of acute brain injury by neuroimaging, in addition to prevention of neuronal shrinkage and the ensuing intraventricular haemorrhage, in premature infants.
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Affiliation(s)
- Fatemeh Bahari
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Volodymyr Dzhala
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Trevor Balena
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Kyle P Lillis
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
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2
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Dzhala VI, Mail M, Staley KJ. Timing of interventions to control neuronal chloride elevation in a model of neonatal seizures after hippocampal injury. Epilepsia 2024. [PMID: 39212418 DOI: 10.1111/epi.18108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 08/16/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024]
Abstract
OBJECTIVE Following hypoxic-ischemic (HI) brain injury, neuronal cytoplasmic chloride concentration ([Cl-]i) increases, potentially contributing to depolarizing γ-aminobutyric acid (GABA) responses, onset of seizures, and the failure of antiepileptic drugs that target inhibitory chloride-permeable GABAA receptors. Post-HI seizures characteristically begin hours after injury, by which time substantial accumulation of [Cl-]i may have already occurred. In immature neurons, a major pathway for Cl- influx is the reversible Na+-K+-2Cl- cotransporter NKCC1. METHODS Spontaneous neuronal network, neuronal [Cl-]i, and GABA activity were determined in hippocampal preparations from neonatal Clomeleon and SuperClomeleon/DLX-cre mice to test whether blocking NKCC1 earlier after oxygen-glucose deprivation (OGD) injury would more effectively ameliorate the increase in [Cl-]i, ictallike epileptiform discharges (ILDs), and the failure of the GABAergic anticonvulsant phenobarbital. RESULTS In vitro, murine intact hippocampi were free of ILDs for 12 h after preparation. Transient OGD resulted in a gradual increase in [Cl-]i, depolarizing action of GABA, and facilitation of neuronal network activity. Spontaneous ILDs began 3-5 h after injury. Blocking NKCC1 with 2-10 μmol·L-1 bumetanide reduced [Cl-]i equally well when applied up to 10 h after injury. Whereas phenobarbital or bumetanide applied separately were less effective when applied later after injury, ILDs were successfully suppressed by the combination of phenobarbital and bumetanide regardless of the number of prior ILDs or delay in application. SIGNIFICANCE The present age-specific group studies demonstrate that after OGD, NKCC1 transport activity significantly contributes to progressive [Cl-]i accumulation, depolarizing action of GABA, and delayed onset of ILDs. In this neonatal model of neuronal injury and ILDs, earlier treatment with bumetanide alone more efficiently recovered control baseline [Cl-]i and depressed epileptiform discharges. However, there was no time dependency to the anti-ictal efficacy of the combination of phenobarbital and bumetanide. These in vitro results suggest that after perinatal injury, early pre-emptive treatment with phenobarbital plus bumetanide would be as efficacious as late treatment after seizures are manifest.
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Affiliation(s)
- Volodymyr I Dzhala
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Michelle Mail
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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3
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Suryavanshi P, Baule S, Glykys J. Trauma in Neonatal Acute Brain Slices Alters Calcium and Network Dynamics and Causes Calpain-Mediated Cell Death. eNeuro 2024; 11:ENEURO.0007-24.2024. [PMID: 38886064 PMCID: PMC11232372 DOI: 10.1523/eneuro.0007-24.2024] [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: 01/02/2024] [Revised: 05/07/2024] [Accepted: 06/06/2024] [Indexed: 06/20/2024] Open
Abstract
Preparing acute brain slices produces trauma that mimics severe penetrating brain injury. In neonatal acute brain slices, the spatiotemporal characteristics of trauma-induced calcium dynamics in neurons and its effect on network activity are relatively unknown. Using multiphoton laser scanning microscopy of the somatosensory neocortex in acute neonatal mouse brain slices (P8-12), we simultaneously imaged neuronal Ca2+ dynamics (GCaMP6s) and cytotoxicity (propidium iodide or PI) to determine the relationship between cytotoxic Ca2+ loaded neurons (GCaMP-filled) and cell viability at different depths and incubation times. PI+ cells and GCaMP-filled neurons were abundant at the surface of the slices, with an exponential decrease with depth. Regions with high PI+ cells correlated with elevated neuronal and neuropil Ca2+ The number of PI+ cells and GCaMP-filled neurons increased with prolonged incubation. GCaMP-filled neurons did not participate in stimulus-evoked or seizure-evoked network activity. Significantly, the superficial tissue, with a higher degree of trauma-induced injury, showed attenuated seizure-related neuronal Ca2+ responses. Calpain inhibition prevented the increase in PI+ cells and GCaMP-filled neurons in the deep tissue and during prolonged incubation times. Isoform-specific pharmacological inhibition implicated calpain-2 as a significant contributor to trauma-induced injury in acute slices. Our results show a calpain-mediated spatiotemporal relationship between cell death and aberrant neuronal Ca2+ load in acute neonatal brain slices. Also, we demonstrate that neurons in acute brain slices exhibit altered physiology depending on the degree of trauma-induced injury. Blocking calpains may be a therapeutic option to prevent acute neuronal death during traumatic brain injury in the young brain.
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Affiliation(s)
- Pratyush Suryavanshi
- Department of Pediatrics, The University of Iowa, Iowa City, Iowa 52241
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52241
| | - Samuel Baule
- Department of Pediatrics, The University of Iowa, Iowa City, Iowa 52241
- Departments of Biomedical Engineering, The University of Iowa, Iowa City, Iowa 52241
| | - Joseph Glykys
- Department of Pediatrics, The University of Iowa, Iowa City, Iowa 52241
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, Iowa 52241
- Neurology, The University of Iowa, Iowa City, Iowa 52241
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4
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Suryavanshi P, Langton R, Fairhead K, Glykys J. Brief and diverse excitotoxic insults cause an increase in neuronal nuclear membrane permeability in the neonatal brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.22.554167. [PMID: 37662276 PMCID: PMC10473591 DOI: 10.1101/2023.08.22.554167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Neuronal swelling after excitotoxic insults is implicated in neuronal injury and death in the developing brain, yet mitigating brain edema with osmotic and surgical interventions yields poor clinical outcomes. Importantly, neuronal swelling and its downstream consequences during early brain development remain poorly investigated. Using multiphoton Ca2+ imaging in vivo (P12-17) and in acute brain slices (P8-12), we explored Ca2+-dependent downstream effects after neuronal cytotoxic edema. We observed the translocation of cytosolic GCaMP6s into the nucleus of a subpopulation of neurons minutes after various excitotoxic insults. We used automated morphology-detection algorithms for neuronal segmentation and quantified the nuclear translocation of GCaMP6s as the ratio of nuclear and cytosolic intensity (N/C ratio). Elevated neuronal N/C ratios were correlated to higher Ca2+ loads and could occur independently of neuronal swelling. Electron microscopy revealed that the nuclear translocation was associated with increased nuclear pore size. Inhibiting calpains prevented elevated N/C ratios and neuronal swelling. Thus, our results indicate altered nuclear transport in a subpopulation of neurons shortly after injury in the developing brain, which can be used as an early biomarker of acute neuronal injury.
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Affiliation(s)
- P Suryavanshi
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - R Langton
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - K Fairhead
- Biomedical Sciences, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA
| | - J Glykys
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
- Department of Neurology, University of Iowa, Iowa City, IA
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5
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Weilinger NL, Yang K, Choi HB, Groten CJ, Wendt S, Murugan M, Wicki-Stordeur LE, Bernier LP, Velayudhan PS, Zheng J, LeDue JM, Rungta RL, Tyson JR, Snutch TP, Wu LJ, MacVicar BA. Pannexin-1 opening in neuronal edema causes cell death but also leads to protection via increased microglia contacts. Cell Rep 2023; 42:113128. [PMID: 37742194 PMCID: PMC10824275 DOI: 10.1016/j.celrep.2023.113128] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/26/2023] [Accepted: 08/28/2023] [Indexed: 09/26/2023] Open
Abstract
Neuronal swelling during cytotoxic edema is triggered by Na+ and Cl- entry and is Ca2+ independent. However, the causes of neuronal death during swelling are unknown. Here, we investigate the role of large-conductance Pannexin-1 (Panx1) channels in neuronal death during cytotoxic edema. Panx1 channel inhibitors reduce and delay neuronal death in swelling triggered by voltage-gated Na+ entry with veratridine. Neuronal swelling causes downstream production of reactive oxygen species (ROS) that opens Panx1 channels. We confirm that ROS activates Panx1 currents with whole-cell electrophysiology and find scavenging ROS is neuroprotective. Panx1 opening and subsequent ATP release attract microglial processes to contact swelling neurons. Depleting microglia using the CSF1 receptor antagonist PLX3397 or blocking P2Y12 receptors exacerbates neuronal death, suggesting that the Panx1-ATP-dependent microglia contacts are neuroprotective. We conclude that cytotoxic edema triggers oxidative stress in neurons that opens Panx1 to trigger death but also initiates neuroprotective feedback mediated by microglia contacts.
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Affiliation(s)
- Nicholas L Weilinger
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Kai Yang
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Hyun B Choi
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Christopher J Groten
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Stefan Wendt
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | | | - Leigh E Wicki-Stordeur
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Louis-Philippe Bernier
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Prashanth S Velayudhan
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jeffrey M LeDue
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ravi L Rungta
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Department of Stomatology and Department of Neuroscience, Université de Montréal, Montréal, QC, Canada
| | - John R Tyson
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Terrance P Snutch
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Brian A MacVicar
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Bollmann Y, Modol L, Tressard T, Vorobyev A, Dard R, Brustlein S, Sims R, Bendifallah I, Leprince E, de Sars V, Ronzitti E, Baude A, Adesnik H, Picardo MA, Platel JC, Emiliani V, Angulo-Garcia D, Cossart R. Prominent in vivo influence of single interneurons in the developing barrel cortex. Nat Neurosci 2023; 26:1555-1565. [PMID: 37653166 DOI: 10.1038/s41593-023-01405-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 07/13/2023] [Indexed: 09/02/2023]
Abstract
Spontaneous synchronous activity is a hallmark of developing brain circuits and promotes their formation. Ex vivo, synchronous activity was shown to be orchestrated by a sparse population of highly connected GABAergic 'hub' neurons. The recent development of all-optical methods to record and manipulate neuronal activity in vivo now offers the unprecedented opportunity to probe the existence and function of hub cells in vivo. Using calcium imaging, connectivity analysis and holographic optical stimulation, we show that single GABAergic, but not glutamatergic, neurons influence population dynamics in the barrel cortex of non-anaesthetized mouse pups. Single GABAergic cells mainly exert an inhibitory influence on both spontaneous and sensory-evoked population bursts. Their network influence scales with their functional connectivity, with highly connected hub neurons displaying the strongest impact. We propose that hub neurons function in tailoring intrinsic cortical dynamics to external sensory inputs.
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Affiliation(s)
- Yannick Bollmann
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Laura Modol
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Thomas Tressard
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Artem Vorobyev
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Robin Dard
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Sophie Brustlein
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Ruth Sims
- Wavefront-Engineering Microscopy Group, Photonics Department, Vision Institute, Sorbonne University, INSERM, CNRS, Paris, France
| | - Imane Bendifallah
- Wavefront-Engineering Microscopy Group, Photonics Department, Vision Institute, Sorbonne University, INSERM, CNRS, Paris, France
| | - Erwan Leprince
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Vincent de Sars
- Wavefront-Engineering Microscopy Group, Photonics Department, Vision Institute, Sorbonne University, INSERM, CNRS, Paris, France
| | - Emiliano Ronzitti
- Wavefront-Engineering Microscopy Group, Photonics Department, Vision Institute, Sorbonne University, INSERM, CNRS, Paris, France
| | - Agnès Baude
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Hillel Adesnik
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Michel Aimé Picardo
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Jean-Claude Platel
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France
| | - Valentina Emiliani
- Wavefront-Engineering Microscopy Group, Photonics Department, Vision Institute, Sorbonne University, INSERM, CNRS, Paris, France
| | - David Angulo-Garcia
- Departamento de Matemáticas y Estadística, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales, Colombia
| | - Rosa Cossart
- Aix Marseille Univ, Inserm, INMED, Turing Center for Living Systems, Marseille, France.
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7
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Byvaltcev E, Behbood M, Schleimer JH, Gensch T, Semyanov A, Schreiber S, Strauss U. KCC2 reverse mode helps to clear postsynaptically released potassium at glutamatergic synapses. Cell Rep 2023; 42:112934. [PMID: 37537840 PMCID: PMC10480490 DOI: 10.1016/j.celrep.2023.112934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/09/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023] Open
Abstract
Extracellular potassium [K+]o elevation during synaptic activity retrogradely modifies presynaptic release and astrocytic uptake of glutamate. Hence, local K+ clearance and replenishment mechanisms are crucial regulators of glutamatergic transmission and plasticity. Based on recordings of astrocytic inward rectifier potassium current IKir and K+-sensitive electrodes as sensors of [K+]o as well as on in silico modeling, we demonstrate that the neuronal K+-Cl- co-transporter KCC2 clears local perisynaptic [K+]o during synaptic excitation by operating in an activity-dependent reversed mode. In reverse mode, KCC2 replenishes K+ in dendritic spines and complements clearance of [K+]o, therewith attenuating presynaptic glutamate release and shortening LTP. We thus demonstrate a physiological role of KCC2 in neuron-glial interactions and regulation of synaptic signaling and plasticity through the uptake of postsynaptically released K+.
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Affiliation(s)
- Egor Byvaltcev
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Mahraz Behbood
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Jan-Hendrik Schleimer
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Thomas Gensch
- Institute of Biological Information Processing 1 (IBI-1, Molecular and Cellular Physiology), Forschungszentrum Jülich, Wilhem-Jonen Straße, 52428 Jülich, Germany
| | - Alexey Semyanov
- Department of Physiology, Jiaxing University College of Medicine, Zhejiang Pro, Jiaxing 314033, China
| | - Susanne Schreiber
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany.
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8
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Balena T, Lillis K, Rahmati N, Bahari F, Dzhala V, Berdichevsky E, Staley K. A Dynamic Balance between Neuronal Death and Clearance in an in Vitro Model of Acute Brain Injury. J Neurosci 2023; 43:6084-6107. [PMID: 37527922 PMCID: PMC10451151 DOI: 10.1523/jneurosci.0436-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/15/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
In in vitro models of acute brain injury, neuronal death may overwhelm the capacity for microglial phagocytosis, creating a queue of dying neurons awaiting clearance. Neurons undergoing programmed cell death are in this queue, and are the most visible and frequently quantified measure of neuronal death after injury. However, the size of this queue should be equally sensitive to changes in neuronal death and the rate of phagocytosis. Using rodent organotypic hippocampal slice cultures as a model of acute perinatal brain injury, serial imaging demonstrated that the capacity for microglial phagocytosis of dying neurons was overwhelmed for 2 weeks. Altering phagocytosis rates (e.g., by changing the number of microglia) dramatically changed the number of visibly dying neurons. Similar effects were generated when the visibility of dying neurons was altered by changing the membrane permeability for stains that label dying neurons. Canonically neuroprotective interventions, such as seizure blockade, and neurotoxic maneuvers, such as perinatal ethanol exposure, were mediated by effects on microglial activity and the membrane permeability of neurons undergoing programmed cell death. These canonically neuroprotective and neurotoxic interventions had either no or opposing effects on healthy surviving neurons identified by the ongoing expression of transgenic fluorescent proteins.SIGNIFICANCE STATEMENT In in vitro models of acute brain injury, microglial phagocytosis is overwhelmed by the number of dying cells. Under these conditions, the assumptions on which assays for neuroprotective and neurotoxic effects are based are no longer valid. Thus, longitudinal assays of healthy cells, such as serial assessment of the fluorescence emission of transgenically expressed proteins, provide more accurate estimates of cell death than do single-time point anatomic or biochemical assays of the number of dying neurons. More accurate estimates of death rates in vitro will increase the translatability of preclinical studies of neuroprotection and neurotoxicity.
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Affiliation(s)
- Trevor Balena
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kyle Lillis
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Negah Rahmati
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Fatemeh Bahari
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Volodymyr Dzhala
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Eugene Berdichevsky
- Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015
| | - Kevin Staley
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
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9
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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10
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Leprince E, Dard RF, Mortet S, Filippi C, Giorgi-Kurz M, Bourboulou R, Lenck-Santini PP, Picardo MA, Bocchio M, Baude A, Cossart R. Extrinsic control of the early postnatal CA1 hippocampal circuits. Neuron 2023; 111:888-902.e8. [PMID: 36608692 DOI: 10.1016/j.neuron.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/18/2022] [Accepted: 12/08/2022] [Indexed: 01/07/2023]
Abstract
The adult CA1 region of the hippocampus produces coordinated neuronal dynamics with minimal reliance on its extrinsic inputs. By contrast, neonatal CA1 is tightly linked to externally generated sensorimotor activity, but the circuit mechanisms underlying early synchronous activity in CA1 remain unclear. Here, using a combination of in vivo and ex vivo circuit mapping, calcium imaging, and electrophysiological recordings in mouse pups, we show that early dynamics in the ventro-intermediate CA1 are under the mixed influence of entorhinal (EC) and thalamic (VMT) inputs. Both VMT and EC can drive internally generated synchronous events ex vivo. However, movement-related population bursts detected in vivo are exclusively driven by the EC. These differential effects on synchrony reflect the different intrahippocampal targets of these inputs. Hence, cortical and subcortical pathways act differently on the neonatal CA1, implying distinct contributions to the development of the hippocampal microcircuit and related cognitive maps.
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Affiliation(s)
- Erwan Leprince
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Robin F Dard
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Salomé Mortet
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Caroline Filippi
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Marie Giorgi-Kurz
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Romain Bourboulou
- Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Michel A Picardo
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Marco Bocchio
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France; Department of Psychology, Durham University, Durham, UK
| | - Agnès Baude
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France
| | - Rosa Cossart
- Aix Marseille University, INSERM, INMED (UMR1249), Turing Centre for Living systems, Marseille, France.
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11
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Luhmann HJ. Malformations-related neocortical circuits in focal seizures. Neurobiol Dis 2023; 178:106018. [PMID: 36706927 DOI: 10.1016/j.nbd.2023.106018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Abstract
This review article gives an overview on the molecular, cellular and network mechanisms underlying focal seizures in neocortical networks with developmental malformations. Neocortical malformations comprise a large variety of structural abnormalities associated with epilepsy and other neurological and psychiatric disorders. Genetic or acquired disorders of neocortical cell proliferation, neuronal migration and/or programmed cell death may cause pathologies ranging from the expression of dysmorphic neurons and heterotopic cell clusters to abnormal layering and cortical misfolding. After providing a brief overview on the pathogenesis and structure of neocortical malformations in humans, animal models are discussed and how they contributed to our understanding on the mechanisms of neocortical hyperexcitability associated with developmental disorders. State-of-the-art molecular biological and electrophysiological techniques have been also used in humans and on resectioned neocortical tissue of epileptic patients and provide deep insights into the subcellular, cellular and network mechanisms contributing to focal seizures. Finally, a brief outlook is given how novel models and methods can shape translational research in the near future.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz, Germany.
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12
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Balena T, Lillis K, Rahmati N, Bahari F, Dzhala V, Berdichevsky E, Staley K. A dynamic balance between neuronal death and clearance after acute brain injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.528332. [PMID: 36824708 PMCID: PMC9948967 DOI: 10.1101/2023.02.14.528332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
After acute brain injury, neuronal apoptosis may overwhelm the capacity for microglial phagocytosis, creating a queue of dying neurons awaiting clearance. The size of this queue should be equally sensitive to changes in neuronal death and the rate of phagocytosis. Using rodent organotypic hippocampal slice cultures as a model of acute perinatal brain injury, serial imaging demonstrated that the capacity for microglial phagocytosis of dying neurons was overwhelmed for two weeks. Altering phagocytosis rates, e.g. by changing the number of microglia, dramatically changed the number of visibly dying neurons. Similar effects were generated when the visibility of dying neurons was altered by changing the membrane permeability for vital stains. Canonically neuroprotective interventions such as seizure blockade and neurotoxic maneuvers such as perinatal ethanol exposure were mediated by effects on microglial activity and the membrane permeability of apoptotic neurons, and had either no or opposing effects on healthy surviving neurons. Significance After acute brain injury, microglial phagocytosis is overwhelmed by the number of dying cells. Under these conditions, the assumptions on which assays for neuroprotective and neurotoxic effects are based are no longer valid. Thus longitudinal assays of healthy cells, such as assessment of the fluorescence emission of transgenically-expressed proteins, provide more accurate estimates of cell death than do single-time-point anatomical or biochemical assays. More accurate estimates of death rates will increase the translatability of preclinical studies of neuroprotection and neurotoxicity.
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13
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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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14
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Using SuperClomeleon to Measure Changes in Intracellular Chloride during Development and after Early Life Stress. eNeuro 2022; 9:ENEURO.0416-22.2022. [PMID: 36635254 PMCID: PMC9797207 DOI: 10.1523/eneuro.0416-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/25/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Intraneuronal chloride concentrations ([Cl-]i) decrease during development resulting in a shift from depolarizing to hyperpolarizing GABA responses via chloride-permeable GABAA receptors. This GABA shift plays a pivotal role in postnatal brain development, and can be strongly influenced by early life experience. Here, we assessed the applicability of the recently developed fluorescent SuperClomeleon (SClm) sensor to examine changes in [Cl-]i using two-photon microscopy in brain slices. We used SClm mice of both sexes to monitor the developmental decrease in neuronal chloride levels in organotypic hippocampal cultures. We could discern a clear reduction in [Cl-]i between day in vitro (DIV)3 and DIV9 (equivalent to the second postnatal week in vivo) and a further decrease in some cells until DIV22. In addition, we assessed alterations in [Cl-]i in the medial prefrontal cortex (mPFC) of postnatal day (P)9 male SClm mouse pups after early life stress (ELS). ELS was induced by limiting nesting material between P2 and P9. ELS induced a shift toward higher (i.e., immature) chloride levels in layer 2/3 cells in the mPFC. Although conversion from SClm fluorescence to absolute chloride concentrations proved difficult, our study underscores that the SClm sensor is a powerful tool to measure physiological changes in [Cl-]i in brain slices.
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15
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Langton RL, Sharma S, Tiarks GC, Bassuk AG, Glykys J. Lacosamide decreases neonatal seizures without increasing apoptosis. Epilepsia 2022; 63:3051-3065. [PMID: 36168798 PMCID: PMC9742288 DOI: 10.1111/epi.17423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/26/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Many seizing neonates fail to respond to first-line anticonvulsant medications. Phenobarbital, an allosteric modulator of γ-aminobutyric acid type A (GABAA ) receptors, has low efficacy in treating neonatal seizures and causes neuronal apoptosis. Nonetheless, it is one of the most used anticonvulsants in this age group. In neonatal mice, phenobarbital's poor effectiveness is due in part to high intraneuronal chloride concentration, which causes GABA to exert depolarizing actions. Therefore, another approach to treat neonatal seizures could be to use anticonvulsants that do not rely on GABAergic modulation. We evaluated whether lacosamide decreases seizures in neonatal mice and whether it increases apoptosis in vitro and in vivo. METHODS In vitro, we measured the effect of different lacosamide concentrations on seizure-like activity induced by the pro-convulsant drug 4-aminopyridine in neocortical brain slices (layer IV/V) from neonatal (postnatal day 8-11) and adult (1-1.6 months old) C57BL/6J mice. In vivo, we recorded the effect of different lacosamide concentrations on neonatal behavioral seizures induced by kainic acid. We studied neocortical apoptosis in vitro and in vivo, measuring terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling signal and cleaved-caspase 3. RESULTS Lacosamide reduced epileptiform activity in neocortical brain slices of neonates and adults in a concentration-dependent manner. In vivo, lacosamide reduced the duration and number of behavioral seizures. Lacosamide did not increase total or neuronal apoptosis in the neocortex in vitro or in vivo. SIGNIFICANCE Lacosamide reduces neocortical seizure-like activity in neonatal mice in vitro and in vivo without an acute increase in apoptosis. Our results support the use of lacosamide to treat neonatal seizures, with the advantage of not increasing apoptosis acutely.
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Affiliation(s)
- Rachel L Langton
- Department of Pediatrics, Division of Child Neurology, University of Iowa, Iowa City, Iowa, USA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Shaunik Sharma
- Department of Pediatrics, Division of Child Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Grant C Tiarks
- Department of Pediatrics, Division of Child Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Alexander G Bassuk
- Department of Pediatrics, Division of Child Neurology, University of Iowa, Iowa City, Iowa, USA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.,Department of Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Joseph Glykys
- Department of Pediatrics, Division of Child Neurology, University of Iowa, Iowa City, Iowa, USA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.,Department of Neurology, University of Iowa, Iowa City, Iowa, USA
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16
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Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [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] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the "dematuration" of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
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Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
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17
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Dzhala V, Fowler AJ, DiMarzio BA, Staley KJ, Suh J. Analysis of brain region-specific mRNA synthesis and stability by utilizing adult mouse brain slice culture. STAR Protoc 2022; 3:101349. [PMID: 35509975 PMCID: PMC9059153 DOI: 10.1016/j.xpro.2022.101349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Utilization of live animals for mechanistic study is challenging yet pivotal to elucidate pathogenesis of neurological diseases. Here, we present a protocol that employs cultured brain slices derived from adult mice to examine mRNA metabolism. We describe the preparation of acute brain slices and the treatments of RNA synthesis inhibitor and nucleotide analog to examine the effects of ataxin-1 loss-of-function on Bace1 mRNA stability and transcription in cortex. This protocol also includes electrophysiological recording of spontaneous neuronal activity in hippocampus. For complete details on the use and execution of this protocol, please refer to Suh et al. (2019). Protocol for acute brain slice cultures derived from adult mice for RNA metabolism study Assessment of gene knockout effects on target mRNA stability in selected brain regions Analysis of mRNA synthesis in cultured brain slices by utilizing Click-iT reaction Electrophysiological analysis of spontaneous neuronal activity in hippocampal slices
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Affiliation(s)
- Volodymyr Dzhala
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
- Corresponding author
| | - Alan J. Fowler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
- Genetics and Aging Research Unit, MassGeneral Institute of Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Britt A. DiMarzio
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
- Genetics and Aging Research Unit, MassGeneral Institute of Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Kevin J. Staley
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Jaehong Suh
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
- Genetics and Aging Research Unit, MassGeneral Institute of Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
- Corresponding author
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18
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Nawafleh S, Qaswal AB, Suleiman A, Alali O, Zayed FM, Al-Adwan MAO, Bani Ali M. GABA Receptors Can Depolarize the Neuronal Membrane Potential via Quantum Tunneling of Chloride Ions: A Quantum Mathematical Study. Cells 2022; 11:cells11071145. [PMID: 35406709 PMCID: PMC8998136 DOI: 10.3390/cells11071145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 01/27/2023] Open
Abstract
GABA (gamma-aminobutyric acid) receptors represent the major inhibitory receptors in the nervous system and their inhibitory effects are mediated by the influx of chloride ions that tends to hyperpolarize the resting membrane potential. However, GABA receptors can depolarize the resting membrane potential and thus can also show excitatory effects in neurons. The major mechanism behind this depolarization is mainly attributed to the accumulation of chloride ions in the intracellular compartment. This accumulation leads to increase in the intracellular chloride concentration and depolarize the Nernst potential of chloride ions. When the membrane potential is relatively hyperpolarized, this will result in a chloride efflux instead of influx trying to reach their depolarized equilibrium potential. Here, we propose different mechanism based on a major consequence of quantum mechanics, which is quantum tunneling. The quantum tunneling model of ions is applied on GABA receptors and their corresponding chloride ions to show how chloride ions can depolarize the resting membrane potential. The quantum model states that intracellular chloride ions have higher quantum tunneling probability than extracellular chloride ions. This is attributed to the discrepancy in the kinetic energy between them. At physiological parameters, the quantum tunneling is negligible to the degree that chloride ions cannot depolarize the membrane potential. Under certain conditions such as early neuronal development, gain-of-function mutations, stroke and trauma that can lower the energy barrier of the closed gate of GABA receptors, the quantum tunneling is enhanced so that the chloride ions can depolarize the resting membrane potential. The major unique feature of the quantum tunneling mechanism is that the net efflux of chloride ions is attained without the need for intracellular accumulation of chloride ions as long as the energy barrier of the gate is reduced but still higher than the kinetic energy of the chloride ion as a condition for quantum tunneling to take place.
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Affiliation(s)
- Sager Nawafleh
- Department of Anesthesia and Intensive Care Unit, The Hashemite University, Zarqa 13115, Jordan
- Correspondence: (S.N.); (A.B.Q.)
| | - Abdallah Barjas Qaswal
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
- Correspondence: (S.N.); (A.B.Q.)
| | - Aiman Suleiman
- Department of Anesthesia, Intensive Care and Pain Management, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA;
| | - Obada Alali
- Department of Anesthesia and Intensive Care, Alabdali Clemenceau Hospital, Amman 11190, Jordan;
| | - Fuad Mohammed Zayed
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
| | | | - Mo’ath Bani Ali
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
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19
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Lodovichi C, Ratto GM, Trevelyan AJ, Arosio D. Genetically encoded sensors for Chloride concentration. J Neurosci Methods 2022; 368:109455. [PMID: 34952088 DOI: 10.1016/j.jneumeth.2021.109455] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 12/12/2022]
Abstract
Insights into chloride regulation in neurons have come slowly, but they are likely to be critical for our understanding of how the brain works. The reason is that the intracellular Cl- level ([Cl-]i) is the key determinant of synaptic inhibitory function, and this in turn dictates all manner of neuronal network function. The true impact on the network will only be apparent, however, if Cl- is measured at many locations at once (multiple neurons, and also across the subcellular compartments of single neurons), which realistically, can only be achieved using imaging. The development of genetically-encoded anion biosensors (GABs) brings the additional benefit that Cl- imaging may be done in identified cell-classes and hopefully in subcellular compartments. Here, we describe the historical background and motivation behind the development of these sensors and how they have been used so far. There are, however, still major limitations for their use, the most important being the fact that all GABs are sensitive to both pH and Cl-. Disambiguating the two signals has proved a major challenge, but there are potential solutions; notable among these is ClopHensor, which has now been developed for in vivo measurements of both ion species. We also speculate on how these biosensors may yet be improved, and how this could advance our understanding of Cl- regulation and its impact on brain function.
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Affiliation(s)
- Claudia Lodovichi
- Neuroscience Institute-CNR, Depart. Biomedical Sciences, Unipd, Padova, Veneto Institute of Molecular Medicine, Padova Neuroscience Center, Padova, Italy.
| | - Gian Michele Ratto
- National Enterprise for nanoScience and nanoTechnology (NEST), Istituto Nanoscienze, Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniele Arosio
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Biofisica, 38123 Trento, Italy.
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20
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DePaula-Silva AB, Bell LA, Wallis GJ, Wilcox KS. Inflammation Unleashed in Viral-Induced Epileptogenesis. Epilepsy Curr 2021; 21:433-440. [PMID: 34924851 PMCID: PMC8652320 DOI: 10.1177/15357597211040939] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Viral infection of the central nervous system increasingly places people at risk of developing life-threatening and treatment-resistant acute and chronic seizures (epilepsy). The emergence of new human viruses due to ongoing social, political, and ecological changes places people at risk more than ever before. The development of new preventative or curative strategies is critical to address this burden. However, our understanding of the complex relationship between viruses and the brain has been hindered by the lack of animal models that survive the initial infection and are amenable for long-term mechanistic, behavioral, and pharmacological studies in the process of viral-induced epileptogenesis. In this review, we focus on the Theiler’s murine encephalomyelitis virus (TMEV) mouse model of viral infection–induced epilepsy. The TMEV model has a number of important advantages to address the quintessential processes underlying the development of epilepsy following a viral infection, as well as fuel new therapeutic development. In this review, we highlight the contributions of the TMEV model to our current understanding of the relationship between viral infection, inflammation, and seizures.
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Affiliation(s)
| | - Laura A. Bell
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
| | - Glenna J. Wallis
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Karen S. Wilcox
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
- Karen S. Wilcox, PhD, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA.
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21
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Kilb W. When Are Depolarizing GABAergic Responses Excitatory? Front Mol Neurosci 2021; 14:747835. [PMID: 34899178 PMCID: PMC8651619 DOI: 10.3389/fnmol.2021.747835] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
The membrane responses upon activation of GABA(A) receptors critically depend on the intracellular Cl− concentration ([Cl−]i), which is maintained by a set of transmembrane transporters for Cl−. During neuronal development, but also under several pathophysiological conditions, the prevailing expression of the Cl− loader NKCC1 and the low expression of the Cl− extruder KCC2 causes elevated [Cl−]i, which result in depolarizing GABAergic membrane responses. However, depolarizing GABAergic responses are not necessarily excitatory, as GABA(A) receptors also reduces the input resistance of neurons and thereby shunt excitatory inputs. To summarize our knowledge on the effect of depolarizing GABA responses on neuronal excitability, this review discusses theoretical considerations and experimental studies illustrating the relation between GABA conductances, GABA reversal potential and neuronal excitability. In addition, evidences for the complex spatiotemporal interaction between depolarizing GABAergic and glutamatergic inputs are described. Moreover, mechanisms that influence [Cl−]i beyond the expression of Cl− transporters are presented. And finally, several in vitro and in vivo studies that directly investigated whether GABA mediates excitation or inhibition during early developmental stages are summarized. In summary, these theoretical considerations and experimental evidences suggest that GABA can act as inhibitory neurotransmitter even under conditions that maintain substantial depolarizing membrane responses.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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22
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Dudok B, Szoboszlay M, Paul A, Klein PM, Liao Z, Hwaun E, Szabo GG, Geiller T, Vancura B, Wang BS, McKenzie S, Homidan J, Klaver LMF, English DF, Huang ZJ, Buzsáki G, Losonczy A, Soltesz I. Recruitment and inhibitory action of hippocampal axo-axonic cells during behavior. Neuron 2021; 109:3838-3850.e8. [PMID: 34648750 PMCID: PMC8639676 DOI: 10.1016/j.neuron.2021.09.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/10/2021] [Accepted: 09/14/2021] [Indexed: 12/16/2022]
Abstract
The axon initial segment of hippocampal pyramidal cells is a key subcellular compartment for action potential generation, under GABAergic control by the "chandelier" or axo-axonic cells (AACs). Although AACs are the only cellular source of GABA targeting the initial segment, their in vivo activity patterns and influence over pyramidal cell dynamics are not well understood. We achieved cell-type-specific genetic access to AACs in mice and show that AACs in the hippocampal area CA1 are synchronously activated by episodes of locomotion or whisking during rest. Bidirectional intervention experiments in head-restrained mice performing a random foraging task revealed that AACs inhibit CA1 pyramidal cells, indicating that the effect of GABA on the initial segments in the hippocampus is inhibitory in vivo. Finally, optogenetic inhibition of AACs at specific track locations induced remapping of pyramidal cell place fields. These results demonstrate brain-state-specific dynamics of a critical inhibitory controller of cortical circuits.
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Affiliation(s)
- Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA.
| | - Miklos Szoboszlay
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Anirban Paul
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Zhenrui Liao
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Ernie Hwaun
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Gergely G Szabo
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Tristan Geiller
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Bert Vancura
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Bor-Shuen Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA
| | - Sam McKenzie
- Department of Neurosciences, University of New Mexico, Albuquerque, NM 87131, USA; NYU Neuroscience Institute, New York University, New York, NY 10016, USA
| | - Jesslyn Homidan
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | | | - Daniel F English
- NYU Neuroscience Institute, New York University, New York, NY 10016, USA; School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA; Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - György Buzsáki
- NYU Neuroscience Institute, New York University, New York, NY 10016, USA
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
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Lombardi A, Luhmann HJ, Kilb W. Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability. PLoS Comput Biol 2021; 17:e1009199. [PMID: 34767548 PMCID: PMC8612559 DOI: 10.1371/journal.pcbi.1009199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/24/2021] [Accepted: 10/24/2021] [Indexed: 11/21/2022] Open
Abstract
GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAergic synapses located at the soma an EGABAThr close to action potential threshold (EAPThr), while with increasing dendritic distance EGABAThr shifted to positive values. The impact of GABA on AMPA-mediated inputs revealed a complex temporal and spatial dependency. EGABAThr depends on the temporal relation between GABA and AMPA inputs, with a striking negative shift in EGABAThr for AMPA inputs appearing after the GABA input. The spatial dependency between GABA and AMPA inputs revealed a complex profile, with EGABAThr being shifted to values negative to EAPThr for AMPA synapses located proximally to the GABA input, while for distally located AMPA synapses the dendritic distance had only a minor effect on EGABAThr. For tonic GABAergic conductances EGABAThr was negative to EAPThr over a wide range of gGABAtonic values. In summary, these results demonstrate that for several physiologically relevant situations EGABAThr is negative to EAPThr, suggesting that depolarizing GABAergic responses can mediate excitatory effects even if EGABA did not reach EAPThr. The neurotransmitter GABA mediates an inhibitory action in the mature brain, while it was found that GABA provokes depolarizations in the immature brain or after neurological insults. It is, however, not clear to which extend these GABAergic depolarizations can contribute to an excitatory effect. In the present manuscript we approached this question with a computational model of a simplified neurons to determine what amount of a GABAergic depolarizing effect, which we quantified by the so called GABA reversal potential (EGABA), was required to turn GABAergic inhibition to excitation. The results of our simulations revealed that if GABA was applied alone a GABAergic excitation was induced when EGABA was around the action potential threshold. When GABA was applied together with additional excitatory inputs, which is the physiological situation in the brain, only for spatially and temporally correlated inputs EGABA was close to the action potential threshold. For situations in which the additional excitatory inputs appear after the GABA input or are distant to the GABA input, an excitatory effect of GABA could be observed already at EGABA substantially negative to the action potential threshold. This results indicate that even slightly depolarizing GABA responses, which may be induced during or after neurological insults, can potentially turn GABAergic inhibition into GABAergic excitation.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Heiko J. Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail:
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24
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Hellas JA, Andrew RD. Neuronal Swelling: A Non-osmotic Consequence of Spreading Depolarization. Neurocrit Care 2021; 35:112-134. [PMID: 34498208 PMCID: PMC8536653 DOI: 10.1007/s12028-021-01326-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/04/2021] [Indexed: 01/22/2023]
Abstract
An acute reduction in plasma osmolality causes rapid uptake of water by astrocytes but not by neurons, whereas both cell types swell as a consequence of lost blood flow (ischemia). Either hypoosmolality or ischemia can displace the brain downwards, potentially causing death. However, these disorders are fundamentally different at the cellular level. Astrocytes osmotically swell or shrink because they express functional water channels (aquaporins), whereas neurons lack functional aquaporins and thus maintain their volume. Yet both neurons and astrocytes immediately swell when blood flow to the brain is compromised (cytotoxic edema) as following stroke onset, sudden cardiac arrest, or traumatic brain injury. In each situation, neuronal swelling is the direct result of spreading depolarization (SD) generated when the ATP-dependent sodium/potassium ATPase (the Na+/K+ pump) is compromised. The simple, and incorrect, textbook explanation for neuronal swelling is that increased Na+ influx passively draws Cl- into the cell, with water following by osmosis via some unknown conduit. We first review the strong evidence that mammalian neurons resist volume change during acute osmotic stress. We then contrast this with their dramatic swelling during ischemia. Counter-intuitively, recent research argues that ischemic swelling of neurons is non-osmotic, involving ion/water cotransporters as well as at least one known amino acid water pump. While incompletely understood, these mechanisms argue against the dogma that neuronal swelling involves water uptake driven by an osmotic gradient with aquaporins as the conduit. Promoting clinical recovery from neuronal cytotoxic edema evoked by spreading depolarizations requires a far better understanding of molecular water pumps and ion/water cotransporters that act to rebalance water shifts during brain ischemia.
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Affiliation(s)
- Julia A Hellas
- Center for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada.
| | - R David Andrew
- Center for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
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25
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Dubanet O, Ferreira Gomes Da Silva A, Frick A, Hirase H, Beyeler A, Leinekugel X. Probing the polarity of spontaneous perisomatic GABAergic synaptic transmission in the mouse CA3 circuit in vivo. Cell Rep 2021; 36:109381. [PMID: 34260906 DOI: 10.1016/j.celrep.2021.109381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 11/18/2020] [Accepted: 06/18/2021] [Indexed: 11/27/2022] Open
Abstract
The hypothesis that reversed, excitatory GABA may be involved in various brain pathologies, including epileptogenesis, is appealing but controversial because of the technical difficulty of probing endogenous GABAergic synaptic function in vivo. We overcome this challenge by non-invasive extracellular recording of neuronal firing responses to optogenetically evoked and spontaneously occurring inhibitory perisomatic GABAergic field potentials, generated by individual parvalbumin interneurons on their target pyramidal cells. Our direct probing of GABAergic transmission suggests a rather anecdotal participation of excitatory GABA in two specific models of epileptogenesis in the mouse CA3 circuit in vivo, even though this does not preclude its expression in other brain areas or pathological conditions. Our approach allows the detection of distinct alterations of inhibition during spontaneous activity in vivo, with high sensitivity. It represents a promising tool for the investigation of excitatory GABA in different pathological conditions that may affect the hippocampal circuit.
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Affiliation(s)
- Olivier Dubanet
- University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Arnaldo Ferreira Gomes Da Silva
- University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France; INMED, INSERM, Aix Marseille Univ, France
| | - Andreas Frick
- University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Hajime Hirase
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Anna Beyeler
- University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Xavier Leinekugel
- University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France; INMED, INSERM, Aix Marseille Univ, France.
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26
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Rahmati N, Normoyle KP, Glykys J, Dzhala VI, Lillis KP, Kahle KT, Raiyyani R, Jacob T, Staley KJ. Unique Actions of GABA Arising from Cytoplasmic Chloride Microdomains. J Neurosci 2021; 41:4957-4975. [PMID: 33903223 PMCID: PMC8197632 DOI: 10.1523/jneurosci.3175-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/10/2021] [Accepted: 04/10/2021] [Indexed: 12/21/2022] Open
Abstract
Developmental, cellular, and subcellular variations in the direction of neuronal Cl- currents elicited by GABAA receptor activation have been frequently reported. We found a corresponding variance in the GABAA receptor reversal potential (EGABA) for synapses originating from individual interneurons onto a single pyramidal cell. These findings suggest a similar heterogeneity in the cytoplasmic intracellular concentration of chloride ([Cl-]i) in individual dendrites. We determined [Cl-]i in the murine hippocampus and cerebral cortex of both sexes by (1) two-photon imaging of the Cl--sensitive, ratiometric fluorescent protein SuperClomeleon; (2) Fluorescence Lifetime IMaging (FLIM) of the Cl--sensitive fluorophore MEQ (6-methoxy-N-ethylquinolinium); and (3) electrophysiological measurements of EGABA by pressure application of GABA and RuBi-GABA uncaging. Fluorometric and electrophysiological estimates of local [Cl-]i were highly correlated. [Cl-]i microdomains persisted after pharmacological inhibition of cation-chloride cotransporters, but were progressively modified after inhibiting the polymerization of the anionic biopolymer actin. These methods collectively demonstrated stable [Cl-]i microdomains in individual neurons in vitro and in vivo and the role of immobile anions in its stability. Our results highlight the existence of functionally significant neuronal Cl- microdomains that modify the impact of GABAergic inputs.SIGNIFICANCE STATEMENT Microdomains of varying chloride concentrations in the neuronal cytoplasm are a predictable consequence of the inhomogeneous distribution of anionic polymers such as actin, tubulin, and nucleic acids. Here, we demonstrate the existence and stability of these microdomains, as well as the consequence for GABAergic synaptic signaling: each interneuron produces a postsynaptic GABAA response with a unique reversal potential. In individual hippocampal pyramidal cells, the range of GABAA reversal potentials evoked by stimulating different interneurons was >20 mV. Some interneurons generated postsynaptic responses in pyramidal cells that reversed at potentials beyond what would be considered purely inhibitory. Cytoplasmic chloride microdomains enable each pyramidal cell to maintain a compendium of unique postsynaptic responses to the activity of individual interneurons.
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Affiliation(s)
- Negah Rahmati
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kieran P Normoyle
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Joseph Glykys
- Department of Pediatrics and Neurology, Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Volodymyr I Dzhala
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kyle P Lillis
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Rehan Raiyyani
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Theju Jacob
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kevin J Staley
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
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27
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Zhu Y, Zhou H, Chen D, Zhou D, Zhao N, Xiong L, Deng I, Zhou X, Zhu Z. New progress of isoflurane, sevoflurane and propofol in hypoxic-ischemic brain injury and related molecular mechanisms based on p75 neurotrophic factor receptor. IBRAIN 2021; 7:132-140. [PMID: 37786902 PMCID: PMC10528789 DOI: 10.1002/j.2769-2795.2021.tb00075.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/17/2021] [Accepted: 06/10/2021] [Indexed: 10/04/2023]
Abstract
Hypoxic ischemic brain injury (HIBI) is one of the most common clinical disorders, especially in neonates. The complex pathophysiology of HIBI is an important cause of disability and even death of patients, however, being without effective clinical treatments. Common anesthetics (such as isoflurane, propofol and sevoflurane) have an adverse impact on neuronal cells for HIBI via the regulation of p75 neurotrophic factor receptor (P75NTR). In order to protect the injured brains and study the effect of underlying treatments, it is particularly significant to understand and master the developmental mechanism of anesthetics for the occurrence of HIBI related molecular mechanisms. Therefore, this paper will mainly review the corresponding pathogenic and protective mechanisms about HIBI binding to the research progress of the role of P75NTR. In conclusion, the effects of neuroprotection and injured nerves are involved in the expression and activation of P75NTR, mainly increased P75NTR mRNA, protein levels and calpain-dependent for propofol, and inducing neuronal apoptosis for isoflurane and sevoflurane, and we look forward to that connection with P75NTR, common anaesthetic and HIBI may be a new direction of research and gain perfect outcomes in the future.
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Affiliation(s)
- Yi Zhu
- School of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Hong‐Su Zhou
- School of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Dong‐Qin Chen
- School of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Di Zhou
- School of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Nan Zhao
- Department of AnesthesiaHospital of Stomatology, Zunyi Medical UniversityZunyiGuizhouChina
| | - Liu‐Lin Xiong
- Clinical and Health Sciences, University of South AustraliaAdelaide5000South AustraliaAustralia
| | - Issac Deng
- Clinical and Health Sciences, University of South AustraliaAdelaide5000South AustraliaAustralia
| | - Xin‐Fu Zhou
- Clinical and Health Sciences, University of South AustraliaAdelaide5000South AustraliaAustralia
| | - Zhao‐Qiong Zhu
- School of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
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28
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Dzhala VI, Staley KJ. KCC2 Chloride Transport Contributes to the Termination of Ictal Epileptiform Activity. eNeuro 2021; 8:ENEURO.0208-20.2020. [PMID: 33239270 PMCID: PMC7986536 DOI: 10.1523/eneuro.0208-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 01/10/2023] Open
Abstract
Recurrent seizures intensely activate GABAA receptors (GABAA-Rs), which induces transient neuronal chloride ([Cl-]i) elevations and depolarizing GABA responses that contribute to the failure of inhibition that engenders further seizures and anticonvulsant resistance. The K+-Cl- cotransporter KCC2 is responsible for Cl- extrusion and restoration of [Cl-]i equilibrium (ECl) after synaptic activity, but at the cost of increased extracellular potassium which may retard K+-Cl- extrusion, depolarize neurons, and potentiate seizures. Thus, KCC2 may either diminish or facilitate seizure activity, and both proconvulsant and anticonvulsant effects of KCC2 inhibition have been reported. It is now necessary to identify the loci of these divergent responses by assaying both the electrographic effects and the ionic effects of KCC2 manipulation. We therefore determined the net effects of KCC2 transport activity on cytoplasmic chloride elevation and Cl- extrusion rates during spontaneous recurrent ictal-like epileptiform discharges (ILDs) in organotypic hippocampal slices in vitro, as well as the correlation between ionic and electrographic effects. We found that the KCC2 antagonist VU0463271 reduced Cl- extrusion rates, increased ictal [Cl-]i elevation, increased ILD duration, and induced status epilepticus (SE). In contrast, the putative KCC2 upregulator CLP257 improved chloride homeostasis and reduced the duration and frequency of ILDs in a concentration-dependent manner. Our results demonstrate that measuring both the ionic and electrographic effects of KCC2 transport clarify the impact of KCC2 modulation in specific models of epileptiform activity. Anticonvulsant effects predominate when KCC2-mediated chloride transport rather than potassium buffering is the rate-limiting step in restoring ECl and the efficacy of GABAergic inhibition during recurrent ILDs.
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Affiliation(s)
- Volodymyr I Dzhala
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114
- Harvard Medical School, Boston, MA 02114
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114
- Harvard Medical School, Boston, MA 02114
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29
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Wu Z, Xie C, Kuang H, Wu J, Chen X, Liu H, Liu T. Oxytocin mediates neuroprotection against hypoxic-ischemic injury in hippocampal CA1 neuron of neonatal rats. Neuropharmacology 2021; 187:108488. [PMID: 33556384 DOI: 10.1016/j.neuropharm.2021.108488] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 01/26/2021] [Accepted: 01/31/2021] [Indexed: 12/13/2022]
Abstract
Neonatal hypoxic-ischemic encephalopathy (NHIE) is one of the most prevalent causes of death during the perinatal period. The lack of exposure to oxytocin is associated with NHIE-mediated severe brain injury. However, the underlying mechanism is not fully understood. This study combined immunohistochemistry with electrophysiological recordings of hippocampal CA1 neurons to investigate the role of oxytocin in an in vitro model of hypoxic-ischemic (HI) injury (oxygen and glucose deprivation, OGD) in postnatal day 7-10 rats. Immunohistochemical analysis showed that oxytocin largely reduced the relative intensity of TOPRO-3 staining following OGD in the hippocampal CA1 region. Whole-cell patch-clamp recording revealed that the OGD-induced onset time of anoxic depolarization (AD) was significantly delayed by oxytocin. This protective effect of oxytocin was blocked by pretreatment with [d(CH2)51, Tyr (Me)2, Thr4, Orn8, des-Gly-NH29] vasotocin (dVOT, an oxytocin receptor antagonist) or bicuculline (a GABAA receptor antagonist). Interestingly, oxytocin enhanced inhibitory postsynaptic currents in CA1 pyramidal neurons, which were abolished by tetrodotoxin or dVOT. In contrast, oxytocin had no effect on excitatory postsynaptic currents but induced an inward current in 86% of the pyramidal neurons tested. Taken together, these results demonstrate that oxytocin receptor signaling plays a critical role in attenuating neonatal neural death by facilitating GABAergic transmission, which may help to regulate the excitatory-inhibitory balance in local neuronal networks in NHIE patients.
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Affiliation(s)
- Zhihong Wu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China
| | - Changning Xie
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China
| | - Haixia Kuang
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China
| | - Jian Wu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China
| | - Xiao Chen
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China
| | - Huibao Liu
- Department of Pediatrics, Xinyu Maternal and Child Health Hospital, 292 S. Laodong, Xinyu, Jiangxi, 338025, PR China.
| | - Tao Liu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, 17 St. Yongwaizheng, Nanchang, Jiangxi, 330006, PR China.
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30
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Lombardi A, Jedlicka P, Luhmann HJ, Kilb W. Coincident glutamatergic depolarizations enhance GABAA receptor-dependent Cl- influx in mature and suppress Cl- efflux in immature neurons. PLoS Comput Biol 2021; 17:e1008573. [PMID: 33465082 PMCID: PMC7845986 DOI: 10.1371/journal.pcbi.1008573] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/29/2021] [Accepted: 11/30/2020] [Indexed: 11/19/2022] Open
Abstract
The impact of GABAergic transmission on neuronal excitability depends on the Cl--gradient across membranes. However, the Cl--fluxes through GABAA receptors alter the intracellular Cl- concentration ([Cl-]i) and in turn attenuate GABAergic responses, a process termed ionic plasticity. Recently it has been shown that coincident glutamatergic inputs significantly affect ionic plasticity. Yet how the [Cl-]i changes depend on the properties of glutamatergic inputs and their spatiotemporal relation to GABAergic stimuli is unknown. To investigate this issue, we used compartmental biophysical models of Cl- dynamics simulating either a simple ball-and-stick topology or a reconstructed CA3 neuron. These computational experiments demonstrated that glutamatergic co-stimulation enhances GABA receptor-mediated Cl- influx at low and attenuates or reverses the Cl- efflux at high initial [Cl-]i. The size of glutamatergic influence on GABAergic Cl--fluxes depends on the conductance, decay kinetics, and localization of glutamatergic inputs. Surprisingly, the glutamatergic shift in GABAergic Cl--fluxes is invariant to latencies between GABAergic and glutamatergic inputs over a substantial interval. In agreement with experimental data, simulations in a reconstructed CA3 pyramidal neuron with physiological patterns of correlated activity revealed that coincident glutamatergic synaptic inputs contribute significantly to the activity-dependent [Cl-]i changes. Whereas the influence of spatial correlation between distributed glutamatergic and GABAergic inputs was negligible, their temporal correlation played a significant role. In summary, our results demonstrate that glutamatergic co-stimulation had a substantial impact on ionic plasticity of GABAergic responses, enhancing the attenuation of GABAergic inhibition in the mature nervous systems, but suppressing GABAergic [Cl-]i changes in the immature brain. Therefore, glutamatergic shift in GABAergic Cl--fluxes should be considered as a relevant factor of short-term plasticity. Information processing in the brain requires that excitation and inhibition are balanced. The main inhibitory neurotransmitter in the brain is gamma-amino-butyric acid (GABA). GABA actions depend on the Cl--gradient, but activation of ionotropic GABA receptors causes Cl--fluxes and thus reduces GABAergic inhibition. Here, we investigated how a coincident membrane depolarization by excitatory glutamatergic synapses influences GABA-induced Cl--fluxes using a biophysical compartmental model of Cl- dynamics, simulating either simple or realistic neuron topologies. We demonstrate that glutamatergic co-stimulation directly affects GABA-induced Cl--fluxes, with the size of glutamatergic effects depending on the conductance, the decay kinetics, and localization of glutamatergic inputs. We also show that the glutamatergic shift in GABAergic Cl--fluxes is surprisingly stable over a substantial range of latencies between glutamatergic and GABAergic inputs. We conclude from these results that glutamatergic co-stimulation alters GABAergic Cl--fluxes and in turn affects the strength of GABAergic inhibition. These coincidence-dependent ionic changes should be considered as a relevant factor of short-term plasticity in the CNS.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Peter Jedlicka
- ICAR3R - Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus-Liebig-University, Giessen, Germany
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, Frankfurt/Main, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
| | - Heiko J. Luhmann
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
- * E-mail:
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31
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Bao J, Graupner M, Astorga G, Collin T, Jalil A, Indriati DW, Bradley J, Shigemoto R, Llano I. Synergism of type 1 metabotropic and ionotropic glutamate receptors in cerebellar molecular layer interneurons in vivo. eLife 2020; 9:56839. [PMID: 32401196 PMCID: PMC7220378 DOI: 10.7554/elife.56839] [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: 03/11/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022] Open
Abstract
Type 1 metabotropic glutamate receptors (mGluR1s) are key elements in neuronal signaling. While their function is well documented in slices, requirements for their activation in vivo are poorly understood. We examine this question in adult mice in vivo using 2-photon imaging of cerebellar molecular layer interneurons (MLIs) expressing GCaMP. In anesthetized mice, parallel fiber activation evokes beam-like Cai rises in postsynaptic MLIs which depend on co-activation of mGluR1s and ionotropic glutamate receptors (iGluRs). In awake mice, blocking mGluR1 decreases Cai rises associated with locomotion. In vitro studies and freeze-fracture electron microscopy show that the iGluR-mGluR1 interaction is synergistic and favored by close association of the two classes of receptors. Altogether our results suggest that mGluR1s, acting in synergy with iGluRs, potently contribute to processing cerebellar neuronal signaling under physiological conditions.
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Affiliation(s)
- Jin Bao
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France.,The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Michael Graupner
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Guadalupe Astorga
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Thibault Collin
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Abdelali Jalil
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Dwi Wahyu Indriati
- Division of Cerebral Structure, National Institute for Physiological Sciences, The Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Jonathan Bradley
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France.,Institut de Biologie de l'Ecole Normale Superieure (IBENS), Ecole Normale Superieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Ryuichi Shigemoto
- Division of Cerebral Structure, National Institute for Physiological Sciences, The Graduate University for Advanced Studies (Sokendai), Okazaki, Japan.,IST Austria, Klosterneuburg, Austria
| | - Isabel Llano
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, Paris, France
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32
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Levinson S, Tran CH, Barry J, Viker B, Levine MS, Vinters HV, Mathern GW, Cepeda C. Paroxysmal Discharges in Tissue Slices From Pediatric Epilepsy Surgery Patients: Critical Role of GABA B Receptors in the Generation of Ictal Activity. Front Cell Neurosci 2020; 14:54. [PMID: 32265658 PMCID: PMC7099654 DOI: 10.3389/fncel.2020.00054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/24/2020] [Indexed: 01/04/2023] Open
Abstract
In the present study, we characterized the effects of bath application of the proconvulsant drug 4-aminopyridine (4-AP) alone or in combination with GABAA and/or GABAB receptor antagonists, in cortical dysplasia (CD type I and CD type IIa/b), tuberous sclerosis complex (TSC), and non-CD cortical tissue samples from pediatric epilepsy surgery patients. Whole-cell patch clamp recordings in current and voltage clamp modes were obtained from cortical pyramidal neurons (CPNs), interneurons, and balloon/giant cells. In pyramidal neurons, bath application of 4-AP produced an increase in spontaneous synaptic activity as well as rhythmic membrane oscillations. In current clamp mode, these oscillations were generally depolarizing or biphasic and were accompanied by increased membrane conductance. In interneurons, membrane oscillations were consistently depolarizing and accompanied by bursts of action potentials. In a subset of balloon/giant cells from CD type IIb and TSC cases, respectively, 4-AP induced very low-amplitude, slow membrane oscillations that echoed the rhythmic oscillations from pyramidal neurons and interneurons. Bicuculline reduced the amplitude of membrane oscillations induced by 4-AP, indicating that they were mediated principally by GABAA receptors. 4-AP alone or in combination with bicuculline increased cortical excitability but did not induce seizure-like discharges. Ictal activity was observed in pyramidal neurons and interneurons from CD and TSC cases only when phaclofen, a GABAB receptor antagonist, was added to the 4-AP and bicuculline solution. These results emphasize the critical and permissive role of GABAB receptors in the transition to an ictal state in pediatric CD tissue and highlight the importance of these receptors as a potential therapeutic target in pediatric epilepsy.
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Affiliation(s)
- Simon Levinson
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Conny H Tran
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joshua Barry
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brett Viker
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S Levine
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Harry V Vinters
- Section of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Gary W Mathern
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Cepeda
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Dossi E, Blauwblomme T, Moulard J, Chever O, Vasile F, Guinard E, Le Bert M, Couillin I, Pallud J, Capelle L, Huberfeld G, Rouach N. Pannexin-1 channels contribute to seizure generation in human epileptic brain tissue and in a mouse model of epilepsy. Sci Transl Med 2019; 10:10/443/eaar3796. [PMID: 29848662 DOI: 10.1126/scitranslmed.aar3796] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 11/02/2017] [Accepted: 05/10/2018] [Indexed: 01/08/2023]
Abstract
Epilepsies are characterized by recurrent seizures, which disrupt normal brain function. Alterations in neuronal excitability and excitation-inhibition balance have been shown to promote seizure generation, yet molecular determinants of such alterations remain to be identified. Pannexin channels are nonselective, large-pore channels mediating extracellular exchange of neuroactive molecules. Recent data suggest that these channels are activated under pathological conditions and regulate neuronal excitability. However, whether pannexin channels sustain or counteract chronic epilepsy in human patients remains unknown. We studied the impact of pannexin-1 channel activation in postoperative human tissue samples from patients with epilepsy displaying epileptic activity ex vivo. These samples were obtained from surgical resection of epileptogenic zones in patients suffering from lesional or drug-resistant epilepsy. We found that pannexin-1 channel activation promoted seizure generation and maintenance through adenosine triphosphate signaling via purinergic 2 receptors. Pharmacological inhibition of pannexin-1 channels with probenecid or mefloquine-two medications currently used for treating gout and malaria, respectively-blocked ictal discharges in human cortical brain tissue slices. Genetic deletion of pannexin-1 channels in mice had anticonvulsant effects when the mice were exposed to kainic acid, a model of temporal lobe epilepsy. Our data suggest a proepileptic role of pannexin-1 channels in chronic epilepsy in human patients and that pannexin-1 channel inhibition might represent an alternative therapeutic strategy for treating lesional and drug-resistant epilepsies.
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Affiliation(s)
- Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Thomas Blauwblomme
- Assistance Publique-Hopitaux de Paris (AP-HP), Department of Pediatric Neurosurgery, Necker Hospital, INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, 75015 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France
| | - Julien Moulard
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Flora Vasile
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Eleonore Guinard
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France
| | - Marc Le Bert
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, 45067 Orléans, France
| | - Isabelle Couillin
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, 45067 Orléans, France
| | - Johan Pallud
- Department of Neurosurgery, Sainte-Anne Hospital and IMA-BRAIN, INSERM U894, Paris Descartes University, PRES Sorbonne Paris Cité, 75014 Paris, France
| | - Laurent Capelle
- Department of Neurosurgery, University Pierre and Marie Curie, La Pitié-Salpêtrière Hospital, AP-HP, Sorbonne Universités, 75013 Paris, France
| | - Gilles Huberfeld
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.,INSERM U1129, Paris Descartes University, PRES Sorbonne Paris Cité, CEA, 75015 Paris, France.,Department of Neurophysiology, La Pitié-Salpetrière Hospital, Sorbonne Universités, University Pierre and Marie Curie, AP-HP, 75013 Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France.
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34
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Inhibition and oscillations in the human brain tissue in vitro. Neurobiol Dis 2019; 125:198-210. [DOI: 10.1016/j.nbd.2019.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/22/2018] [Accepted: 02/07/2019] [Indexed: 01/22/2023] Open
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35
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Hsu Y, Chang Y, Liu Y, Wang K, Chen H, Lee D, Yang S, Tsai C, Lien C, Chern Y. Enhanced Na
+
‐K
+
‐2Cl
‐
cotransporter 1 underlies motor dysfunction in huntington's disease. Mov Disord 2019; 34:845-857. [DOI: 10.1002/mds.27651] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/29/2019] [Accepted: 02/04/2019] [Indexed: 01/17/2023] Open
Affiliation(s)
- Yi‐Ting Hsu
- PhD Program for Translational MedicineChina Medical University and Academia Sinica Taipei Taiwan
- Department of NeurologyChina Medical University Hospital Taichung Taiwan
| | - Ya‐Gin Chang
- Institute of NeuroscienceNational Yang‐Ming University Taipei Taiwan
- Taiwan International Graduate Program in Interdisciplinary NeuroscienceNational Yang‐Ming University and Academia Sinica Taipei Taiwan
| | - Yu‐Chao Liu
- Institute of NeuroscienceNational Yang‐Ming University Taipei Taiwan
| | - Kai‐Yi Wang
- Institute of NeuroscienceNational Yang‐Ming University Taipei Taiwan
| | - Hui‐Mei Chen
- Institute of Biomedical SciencesAcademia Sinica Taipei Taiwan
| | - Ding‐Jin Lee
- PhD Program for Translational MedicineChina Medical University and Academia Sinica Taipei Taiwan
| | - Sung‐Sen Yang
- Division of Nephrology, Department of Medicine, Tri‐Service General HospitalNational Defense Medical Center Taipei Taiwan
| | - Chon‐Haw Tsai
- PhD Program for Translational MedicineChina Medical University and Academia Sinica Taipei Taiwan
- Department of NeurologyChina Medical University Hospital Taichung Taiwan
| | - Cheng‐Chang Lien
- Institute of NeuroscienceNational Yang‐Ming University Taipei Taiwan
- Brain Research CenterNational Yang‐Ming University Taipei Taiwan
| | - Yijuang Chern
- PhD Program for Translational MedicineChina Medical University and Academia Sinica Taipei Taiwan
- Institute of NeuroscienceNational Yang‐Ming University Taipei Taiwan
- Institute of Biomedical SciencesAcademia Sinica Taipei Taiwan
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36
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Shao LR, Habela CW, Stafstrom CE. Pediatric Epilepsy Mechanisms: Expanding the Paradigm of Excitation/Inhibition Imbalance. CHILDREN-BASEL 2019; 6:children6020023. [PMID: 30764523 PMCID: PMC6406372 DOI: 10.3390/children6020023] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 02/07/2023]
Abstract
Mechanisms underlying seizures and epilepsy have traditionally been considered to involve abnormalities of ion channels or synaptic function. Those considerations gave rise to the excitation/inhibition (E/I) imbalance theory, whereby increased excitation, decreased inhibition, or both favor a hyperexcitable state and an increased propensity for seizure generation and epileptogenesis. Several recent findings warrant reconsideration and expansion of the E/I hypothesis: novel genetic mutations have been identified that do not overtly affect E/I balance; neurotransmitters may exert paradoxical effects, especially during development; anti-seizure medications do not necessarily work by decreasing excitation or increasing inhibition; and metabolic factors participate in the regulation of neuronal and network excitability. These novel conceptual and experimental advances mandate expansion of the E/I paradigm, with the expectation that new and exciting therapies will emerge from this broadened understanding of how seizures and epilepsy arise and progress.
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Affiliation(s)
- Li-Rong Shao
- Division of Pediatric Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
| | - Christa W Habela
- Division of Pediatric Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
| | - Carl E Stafstrom
- Division of Pediatric Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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37
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Glykys J, Duquette E, Rahmati N, Duquette K, Staley KJ. Mannitol decreases neocortical epileptiform activity during early brain development via cotransport of chloride and water. Neurobiol Dis 2019; 125:163-175. [PMID: 30711483 DOI: 10.1016/j.nbd.2019.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 12/31/2022] Open
Abstract
Seizures and brain injury lead to water and Cl- accumulation in neurons. The increase in intraneuronal Cl- concentration ([Cl-]i) depolarizes the GABAA reversal potential (EGABA) and worsens seizure activity. Neocortical neuronal membranes have a low water permeability due to the lack of aquaporins necessary to move free water. Instead, neurons use cotransport of ions including Cl- to move water. Thus, increasing the extracellular osmolarity during seizures should result in an outward movement of water and salt, reducing [Cl-]i and improving GABAA receptor-mediated inhibition. We tested the effects of hyperosmotic therapy with a clinically relevant dose of mannitol (20 mM) on epileptiform activity, spontaneous multiunit activity, spontaneous inhibitory post-synaptic currents (sIPSCs), [Cl-]i, and neuronal volume in layer IV/V of the developing neocortex of C57BL/6 and Clomeleon mice. Using electrophysiological techniques and multiphoton imaging in acute brain slices (post-natal day 7-12) and organotypic neocortical slice cultures (post-natal day 14), we observed that mannitol: 1) decreased epileptiform activity, 2) decreased neuronal volume and [Cl-]i through CCCs, 3) decreased spontaneous multi-unit activity frequency but not amplitude, and 4) restored the anticonvulsant efficacy of the GABAA receptor modulator diazepam. Increasing extracellular osmolarity by 20 mOsm with hypertonic saline did not decrease epileptiform activity. We conclude that an increase in extracellular osmolarity by mannitol mediates the efflux of [Cl-]i and water through CCCs, which results in a decrease in epileptiform activity and enhances benzodiazepine actions in the developing neocortex in vitro. Novel treatments aimed to decrease neuronal volume may concomitantly decrease [Cl-]i and improve seizure control.
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Affiliation(s)
- J Glykys
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States.
| | - E Duquette
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States
| | - N Rahmati
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States
| | - K Duquette
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Northeastern University, Boston 02115, United States
| | - K J Staley
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States
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38
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Lombardi A, Jedlicka P, Luhmann HJ, Kilb W. Giant Depolarizing Potentials Trigger Transient Changes in the Intracellular Cl - Concentration in CA3 Pyramidal Neurons of the Immature Mouse Hippocampus. Front Cell Neurosci 2018; 12:420. [PMID: 30515078 PMCID: PMC6255825 DOI: 10.3389/fncel.2018.00420] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/26/2018] [Indexed: 11/30/2022] Open
Abstract
Giant depolarizing potentials (GDPs) represent a typical spontaneous activity pattern in the immature hippocampus. GDPs are mediated by GABAergic and glutamatergic synaptic inputs and their initiation requires an excitatory GABAergic action, which is typical for immature neurons due to their elevated intracellular Cl- concentration ([Cl-]i). Because GABAA receptors are ligand-gated Cl- channels, activation of these receptors can potentially influence [Cl-]i. However, whether the GABAergic activity during GDPs influences [Cl-]i is unclear. To address this question we performed whole-cell and gramicidin-perforated patch-clamp recordings from visually identified CA3 pyramidal neurons in immature hippocampal slices of mice at postnatal days 4–7. These experiments revealed that the [Cl-]i of CA3 neurons displays a considerable heterogeneity, ranging from 13 to 70 mM (average 38.1 ± 3.2 mM, n = 36). In accordance with this diverse [Cl-]i, GDPs induced either Cl--effluxes or Cl--influxes. In high [Cl-]i neurons with a negative Cl--driving force (DFCl) the [Cl-]i decreased after a GDP by 12.4 ± 3.4 mM (n = 10), while in low [Cl-]i neurons with a positive DFCl [Cl-]i increased by 4.4 ± 0.9 mM (n = 6). Inhibition of GDP activity by application of the AMPA receptor antagonist CNQX led to a [Cl-]i decrease to 24.7 ± 2.9 mM (n = 8). We conclude from these results, that Cl--fluxes via GABAA receptors during GDPs induced substantial [Cl-]i changes and that this activity-dependent ionic plasticity in neuronal [Cl-]i contributes to the functional consequences of GABAergic responses, emphasizing the concept that [Cl-]i is a state- and compartment-dependent parameter of individual cells.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Peter Jedlicka
- Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus Liebig University Giessen, Giessen, Germany.,Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany
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39
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Shibuta S, Morita T, Kosaka J. Intravenous anesthetic-induced calcium dysregulation and neurotoxic shift with age during development in primary cultured neurons. Neurotoxicology 2018; 69:320-329. [PMID: 30107222 DOI: 10.1016/j.neuro.2018.08.002] [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: 01/28/2018] [Revised: 07/29/2018] [Accepted: 08/08/2018] [Indexed: 10/28/2022]
Abstract
Anesthetic-induced neurotoxicity in the developing brain is a concern. This neurotoxicity is closely related to anesthetic exposure time, dose, and developmental stages. Using calcium imaging and morphological examinations in vitro, we sought to determine whether intravenous anesthetic-induced direct neurotoxicity varies according to different stages of the days in vitro (DIV) of neurons in primary culture. Cortical neurons from E17 Wistar rats were prepared. On DIV 3, 7, and 13, cells were exposed to the intravenous anesthetics thiopental sodium (TPS), midazolam (MDZ), or propofol (PPF), to investigate direct neurotoxicity using morphological experiments. Furthermore, using calcium imaging, the anesthetic-induced intracellular calcium concentration ([Ca2+]i) elevation was monitored in cells on DIV 4, 8, and 13. All anesthetics elicited significant [Ca2+]i increases on DIV 4. While TPS (100 μM) and MDZ (10 μM) did not alter neuronal death, PPF (10 μM and 100 μM) decreased the survival ratio (SR) significantly. On DIV 8, TPS and MDZ did not elicit [Ca2+]i elevation or SR decrease, while PPF still induced [Ca2+]i elevation (both at 10 μM and 100 μM) and significant SR decrease at 100 μM (0.76 ± 0.03; P < 0.05), but not at 10 μM (0.91 ± 0.03). Such anesthetic-induced [Ca2+]i elevation and SR decrease were not observed on DIV 13-14 for any of the anesthetic drugs. Our study indicates that more caution may be exercised when using PPF compared to TPS or MDZ during development.
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Affiliation(s)
- Satoshi Shibuta
- Department of Anesthesiology and Intensive Care Medicine, International University of Health and Welfare, Narita, Chiba, Japan; Department of Anesthesiology and Intensive Care Medicine, Osaka University, Suita, Osaka, Japan.
| | - Tomotaka Morita
- Department of Anesthesiology and Intensive Care Medicine, Osaka University, Suita, Osaka, Japan.
| | - Jun Kosaka
- Department of Anatomy, International University of Health and Welfare, Narita, Chiba, Japan.
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40
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Blauwblomme T, Dzhala V, Staley K. Transient ischemia facilitates neuronal chloride accumulation and severity of seizures. Ann Clin Transl Neurol 2018; 5:1048-1061. [PMID: 30250862 PMCID: PMC6144438 DOI: 10.1002/acn3.617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 06/11/2018] [Indexed: 12/29/2022] Open
Abstract
Objective Preceding oxygen glucose deprivation (OGD) and ongoing seizures have both been reported to increase neuronal chloride concentration ([Cl−]i), which may contribute to anticonvulsant failure by reversing the direction of chloride currents at inhibitory GABAA synapses. Methods The effects of OGD on [Cl−]i, seizure activity, and anticonvulsant efficacy were studied in a chronically epileptic in vitro preparation. Results Seizures initially increased during OGD, followed by suppression. On reperfusion, seizure frequency and [Cl−]i progressively increased, and phenobarbital efficacy was reduced. Bumetanide (10 μmol/L) and furosemide (1 mmol/L) prevented or reduced the OGD induced [Cl−]i increase. Phenobarbital efficacy was enhanced by bumetanide (10 μmol/L). Furosemide (1 mmol/L) suppressed recurrent seizures. Interpretation [Cl−]i increases after OGD and is associated with worsened seizure activity, reduced efficacy of GABAergic anticonvulsants, and amelioration by antagonists of secondary chloride transport.
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Affiliation(s)
- Thomas Blauwblomme
- Department of Neurology Massachusetts General Hospital and Harvard Medical School Boston Massachusetts 02114.,Universite Paris Descartes Sorbonne Paris Cite Paris France
| | - Volodymyr Dzhala
- Department of Neurology Massachusetts General Hospital and Harvard Medical School Boston Massachusetts 02114
| | - Kevin Staley
- Department of Neurology Massachusetts General Hospital and Harvard Medical School Boston Massachusetts 02114
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41
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Reality of Inhibitory GABA in Neonatal Brain: Time to Rewrite the Textbooks? J Neurosci 2018; 36:10242-10244. [PMID: 27707962 DOI: 10.1523/jneurosci.2270-16.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/26/2016] [Indexed: 12/30/2022] Open
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42
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Developmental excitatory-to-inhibitory GABA polarity switch is delayed in Ts65Dn mice, a genetic model of Down syndrome. Neurobiol Dis 2018; 115:1-8. [PMID: 29550538 DOI: 10.1016/j.nbd.2018.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 11/23/2022] Open
Abstract
Down syndrome (DS) is the most frequent genetic cause of developmental abnormalities leading to intellectual disability. One notable phenomenon affecting the formation of nascent neural circuits during late developmental periods is developmental switch of GABA action from depolarizing to hyperpolarizing mode. We examined properties of this switch in DS using primary cultures and acute hippocampal slices from Ts65Dn mice, a genetic model of DS. Cultures of DIV3-DIV13 Ts65Dn and control normosomic (2 N) neurons were loaded with FURA-2 AM, and GABA action was assessed using local applications. In 2 N cultures, the number of GABA-activated cells dropped from ~100% to 20% between postnatal days 3-13 (P3-P13) reflecting the switch in GABA action polarity. In Ts65Dn cultures, the timing of this switch was delayed by 2-3 days. Next, microelectrode recordings of multi-unit activity (MUA) were performed in CA3 slices during bath application of the GABAA agonist isoguvacine. MUA frequency was increased in P8-P12 and reduced in P14-P22 slices reflecting the switch of GABA action from excitatory to inhibitory mode. The timing of this switch was delayed in Ts65Dn by approximately 2 days. Finally, frequency of giant depolarizing potentials (GDPs), a form of primordial neural activity, was significantly increased in slices from Ts65Dn pups at P12 and P14. These experimental evidences show that GABA action polarity switch is delayed in Ts65Dn model of DS, and that these changes lead to a delay in maturation of nascent neural circuits. These alterations may affect properties of neural circuits in adult animals and, therefore, represent a prospective target for pharmacotherapy of cognitive impairment in DS.
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43
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França KLDA, de Almeida ACG, Saddow SE, Santos LEC, Scorza CA, Scorza FA, Rodrigues AM. GABA a excitation and synaptogenesis after Status Epilepticus - A computational study. Sci Rep 2018; 8:4193. [PMID: 29520076 PMCID: PMC5843660 DOI: 10.1038/s41598-018-22581-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/23/2018] [Indexed: 11/09/2022] Open
Abstract
The role of GABAergic neurotransmission on epileptogenesis has been the subject of speculation according to different approaches. However, it is a very complex task to specifically consider the action of the GABAa neurotransmitter, which, in its dependence on the intracellular level of Cl-, can change its effect from inhibitory to excitatory. We have developed a computational model that represents the dentate gyrus and is composed of three different populations of neurons (granule cells, interneurons and mossy cells) that are mutually interconnected. The interconnections of the neurons were based on compensation theory with Hebbian and anti-Hebbian rules. The model also incorporates non-synaptic mechanisms to control the ionic homeostasis and was able to reproduce ictal discharges. The goal of the work was to investigate the hypothesis that the observed aberrant sprouting is promoted by GABAa excitatory action. Conjointly with the abnormal sprouting of the mossy fibres, the simulations show a reduction of the mossy cells connections in the network and an increased inhibition of the interneurons as a response of the neuronal network to control the activity. This finding contributes to increasing the changes in the connectivity of the neuronal circuitry and to increasing the epileptiform activity occurrences.
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Affiliation(s)
- Keite Lira de Almeida França
- Laboratório de Neurociência Experimental e Computacional (LANEC), Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei (UFSJ), São João del-Rei, Brazil
| | - Antônio-Carlos Guimarães de Almeida
- Laboratório de Neurociência Experimental e Computacional (LANEC), Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei (UFSJ), São João del-Rei, Brazil
| | - Stephen E Saddow
- Electrical Engineering Department, University of South of Florida, Tampa, FL, USA
| | - Luiz Eduardo Canton Santos
- Laboratório de Neurociência Experimental e Computacional (LANEC), Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei (UFSJ), São João del-Rei, Brazil
| | | | | | - Antônio Márcio Rodrigues
- Laboratório de Neurociência Experimental e Computacional (LANEC), Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei (UFSJ), São João del-Rei, Brazil.
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Klein PM, Lu AC, Harper ME, McKown HM, Morgan JD, Beenhakker MP. Tenuous Inhibitory GABAergic Signaling in the Reticular Thalamus. J Neurosci 2018; 38:1232-1248. [PMID: 29273603 PMCID: PMC5792478 DOI: 10.1523/jneurosci.1345-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/20/2017] [Accepted: 11/03/2017] [Indexed: 11/21/2022] Open
Abstract
Maintenance of a low intracellular Cl- concentration ([Cl-]i) is critical for enabling inhibitory neuronal responses to GABAA receptor-mediated signaling. Cl- transporters, including KCC2, and extracellular impermeant anions ([A]o) of the extracellular matrix are both proposed to be important regulators of [Cl-]i Neurons of the reticular thalamic (RT) nucleus express reduced levels of KCC2, indicating that GABAergic signaling may produce excitation in RT neurons. However, by performing perforated patch recordings and calcium imaging experiments in rats (male and female), we find that [Cl-]i remains relatively low in RT neurons. Although we identify a small contribution of [A]o to a low [Cl-]i in RT neurons, our results also demonstrate that reduced levels of KCC2 remain sufficient to maintain low levels of Cl- Reduced KCC2 levels, however, restrict the capacity of RT neurons to rapidly extrude Cl- following periods of elevated GABAergic signaling. In a computational model of a local RT network featuring slow Cl- extrusion kinetics, similar to those we found experimentally, model RT neurons are predisposed to an activity-dependent switch from GABA-mediated inhibition to excitation. By decreasing the activity threshold required to produce excitatory GABAergic signaling, weaker stimuli are able to propagate activity within the model RT nucleus. Our results indicate the importance of even diminished levels of KCC2 in maintaining inhibitory signaling within the RT nucleus and suggest how this important activity choke point may be easily overcome in disorders such as epilepsy.SIGNIFICANCE STATEMENT Precise regulation of intracellular Cl- levels ([Cl-]i) preserves appropriate, often inhibitory, GABAergic signaling within the brain. However, there is disagreement over the relative contribution of various mechanisms that maintain low [Cl-]i We found that the Cl- transporter KCC2 is an important Cl- extruder in the reticular thalamic (RT) nucleus, despite this nucleus having remarkably low KCC2 immunoreactivity relative to other regions of the adult brain. We also identified a smaller contribution of fixed, impermeant anions ([A]o) to lowering [Cl-]i in RT neurons. Inhibitory signaling among RT neurons is important for preventing excessive activation of RT neurons, which can be responsible for generating seizures. Our work suggests that KCC2 critically restricts the spread of activity within the RT nucleus.
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Affiliation(s)
- Peter M Klein
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Adam C Lu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Megan E Harper
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Hannah M McKown
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Jessica D Morgan
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
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45
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Boffi JC, Knabbe J, Kaiser M, Kuner T. KCC2-dependent Steady-state Intracellular Chloride Concentration and pH in Cortical Layer 2/3 Neurons of Anesthetized and Awake Mice. Front Cell Neurosci 2018; 12:7. [PMID: 29422838 PMCID: PMC5788967 DOI: 10.3389/fncel.2018.00007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/05/2018] [Indexed: 12/31/2022] Open
Abstract
Neuronal intracellular Cl− concentration ([Cl−]i) influences a wide range of processes such as neuronal inhibition, membrane potential dynamics, intracellular pH (pHi) or cell volume. Up to date, neuronal [Cl−]i has predominantly been studied in model systems of reduced complexity. Here, we implemented the genetically encoded ratiometric Cl− indicator Superclomeleon (SCLM) to estimate the steady-state [Cl−]i in cortical neurons from anesthetized and awake mice using 2-photon microscopy. Additionally, we implemented superecliptic pHluorin (SE-pHluorin) as a ratiometric sensor to estimate the intracellular steady-state pH (pHi) of mouse cortical neurons in vivo. We estimated an average resting [Cl−]i of 6 ± 2 mM with no evidence of subcellular gradients in the proximal somato-dendritic domain and an average somatic pHi of 7.1 ± 0.2. Neither [Cl−]i nor pHi were affected by isoflurane anesthesia. We deleted the cation-Cl− co-transporter KCC2 in single identified neurons of adult mice and found an increase of [Cl−]i to approximately 26 ± 8 mM, demonstrating that under in vivo conditions KCC2 produces low [Cl−]i in adult mouse neurons. In summary, neurons of the brain of awake adult mice exhibit a low and evenly distributed [Cl−]i in the proximal somato-dendritic compartment that is independent of anesthesia and requires KCC2 expression for its maintenance.
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Affiliation(s)
- Juan C Boffi
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Johannes Knabbe
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Michaela Kaiser
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
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46
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Raimondo JV, Heinemann U, de Curtis M, Goodkin HP, Dulla CG, Janigro D, Ikeda A, Lin CCK, Jiruska P, Galanopoulou AS, Bernard C. Methodological standards for in vitro models of epilepsy and epileptic seizures. A TASK1-WG4 report of the AES/ILAE Translational Task Force of the ILAE. Epilepsia 2017; 58 Suppl 4:40-52. [PMID: 29105075 DOI: 10.1111/epi.13901] [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] [Accepted: 02/13/2017] [Indexed: 01/02/2023]
Abstract
In vitro preparations are a powerful tool to explore the mechanisms and processes underlying epileptogenesis and ictogenesis. In this review, we critically review the numerous in vitro methodologies utilized in epilepsy research. We provide support for the inclusion of detailed descriptions of techniques, including often ignored parameters with unpredictable yet significant effects on study reproducibility and outcomes. In addition, we explore how recent developments in brain slice preparation relate to their use as models of epileptic activity.
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Affiliation(s)
- Joseph V Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Uwe Heinemann
- Neuroscience Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Marco de Curtis
- Epilepsy and Experimental Neurophysiology Unit, The Foundation of the Carlo Besta Neurological Institute, Milan, Italy
| | - Howard P Goodkin
- Departments of Neurology and Pediatrics, University of Virginia, Charlottesville, Virginia, U.S.A
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, U.S.A
| | - Damir Janigro
- Flocel Inc., Cleveland, Ohio, U.S.A.,Case Western Reserve University, Cleveland, Ohio, U.S.A
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders, and Physiology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan
| | - Chou-Ching K Lin
- Department of Neurology, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Premysl Jiruska
- Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Aristea S Galanopoulou
- Laboratory of Developmental Epilepsy, Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, New York, U.S.A
| | - Christophe Bernard
- Inserm, Institut de Neurosciences des Systemes UMRS 1106, Aix Marseille University, Marseille, France
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47
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Winland CD, Welsh N, Sepulveda-Rodriguez A, Vicini S, Maguire-Zeiss KA. Inflammation alters AMPA-stimulated calcium responses in dorsal striatal D2 but not D1 spiny projection neurons. Eur J Neurosci 2017; 46:2519-2533. [PMID: 28921719 PMCID: PMC5673553 DOI: 10.1111/ejn.13711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 12/22/2022]
Abstract
Neuroinflammation precedes neuronal loss in striatal neurodegenerative diseases and can be exacerbated by the release of proinflammatory molecules by microglia. These molecules can affect trafficking of AMPARs. The preferential trafficking of calcium-permeable versus impermeable AMPARs can result in disruptions of [Ca2+ ]i and alter cellular functions. In striatal neurodegenerative diseases, changes in [Ca2+ ]i and L-type voltage-gated calcium channels (VGCCs) have been reported. Therefore, this study sought to determine whether a proinflammatory environment alters AMPA-stimulated [Ca2+ ]i through calcium-permeable AMPARs and/or L-type VGCCs in dopamine-2- and dopamine-1-expressing striatal spiny projection neurons (D2 and D1 SPNs) in the dorsal striatum. Mice expressing the calcium indicator protein, GCaMP in D2 or D1 SPNs, were utilized for calcium imaging. Microglial activation was assessed by morphology analyses. To induce inflammation, acute mouse striatal slices were incubated with lipopolysaccharide (LPS). Here we report that LPS treatment potentiated AMPA responses only in D2 SPNs. When a nonspecific VGCC blocker was included, we observed a decrease of AMPA-stimulated calcium fluorescence in D2 but not D1 SPNs. The remaining agonist-induced [Ca2+ ]i was mediated by calcium-permeable AMPARs because the responses were completely blocked by a selective calcium-permeable AMPAR antagonist. We used isradipine, the highly selective L-type VGCC antagonist to determine the role of L-type VGCCs in SPNs treated with LPS. Isradipine decreased AMPA-stimulated responses selectively in D2 SPNs after LPS treatment. Our findings suggest that dorsal striatal D2 SPNs are specifically targeted in proinflammatory conditions and that L-type VGCCs and calcium-permeable AMPARs are important mediators of this effect.
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MESH Headings
- Animals
- CX3C Chemokine Receptor 1/genetics
- CX3C Chemokine Receptor 1/metabolism
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/metabolism
- Cations, Divalent/metabolism
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Corpus Striatum/pathology
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Dopaminergic Neurons/pathology
- Female
- Inflammation/metabolism
- Inflammation/pathology
- Lipopolysaccharides
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Microglia/drug effects
- Microglia/metabolism
- Microglia/pathology
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Tissue Culture Techniques
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/metabolism
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Affiliation(s)
- Carissa D. Winland
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Nora Welsh
- Department of Biology, Georgetown University, Washington, D.C. 20007 USA
| | - Alberto Sepulveda-Rodriguez
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Stefano Vicini
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C. 20007 USA
| | - Kathleen A. Maguire-Zeiss
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Neuroscience, Georgetown University Medical Center, Washington, D.C. 20007 USA
- Department of Biology, Georgetown University, Washington, D.C. 20007 USA
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48
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Concerted Interneuron Activity in the Cerebellar Molecular Layer During Rhythmic Oromotor Behaviors. J Neurosci 2017; 37:11455-11468. [PMID: 29066561 DOI: 10.1523/jneurosci.1091-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 10/10/2017] [Accepted: 10/17/2017] [Indexed: 01/02/2023] Open
Abstract
Molecular layer interneurons (MLIs, stellate and basket cells) of the cerebellar cortex are linked together by chemical and electrical synapses and exert a potent feedforward inhibition on Purkinje cells. The functional role of MLIs during specific motor tasks is uncertain. Here, we used two-photon imaging to study the patterns of activity of neighboring individual MLIs in the Crus II region of awake female mice during two types of oromotor activity, licking and bruxing, using specific expression of the genetically encoded calcium indicator protein GCaMP6s. We found that both stellate and basket cells engaged in synchronized waves of calcium activity during licking and bruxing, with high degrees of correlation among the signals collected in individual MLIs. In contrast, no calcium activity was observed during whisking. MLI activity tended to lag behind the onset of sustained licking episodes, indicating a regulatory action of MLIs during licking. Furthermore, during licking, stellate cell activity was anisotropic: the coordination was constant along the direction of parallel fibers (PFs), but fell off with distance along the orthogonal direction. These results suggest a PF drive for Ca2+ signals during licking. In contrast, during bruxing, MLI activity was neither clearly organized spatially nor temporally correlated with oromotor activity. In conclusion, MLI activity exhibits a high degree of correlation both in licking and in bruxing, but spatiotemporal patterns of activity display significant differences for the two types of behavior.SIGNIFICANCE STATEMENT It is known that, during movement, the activity of molecular layer interneurons (MLIs) of the cerebellar cortex is enhanced. However, MLI-MLI interactions are complex because they depend both from excitatory electrical synapses and from potentially inhibitory chemical synapses. Accordingly, the pattern of MLI activity during movement has been unclear. Here, during two oromotor tasks, licking and bruxism, individual neighboring MLIs displayed highly coordinated activity, showing that the positive influences binding MLIs together are predominant. We further find that spatiotemporal patterns differ between licking and bruxing, suggesting that the precise pattern of MLI activity depends on the nature of the motor task.
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49
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Friedman SD, Poliakov AV, Budech C, Shaw DWW, Breiger D, Jinguji T, Krabak B, Coppel D, Lewis TM, Browd S, Ojemann JG. GABA alterations in pediatric sport concussion. Neurology 2017; 89:2151-2156. [PMID: 29030453 DOI: 10.1212/wnl.0000000000004666] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/06/2017] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To evaluate whether frontal-lobe magnetic resonance spectroscopy measures of γ-aminobutyric acid (GABA) would be altered in a sample of adolescents scanned after sport concussion because mild traumatic brain injury is often associated with working memory problems. METHODS Eleven adolescents (age 14-17 years) who had sustained a first-time sport concussion were studied with MRI/magnetic resonance spectroscopy within 23 to 44 days after injury (mean 30.4 ± 6.1 days). Age- and sex-matched healthy controls, being seen for sports-related injuries not involving the head and with no history of concussion, were also examined. GABA/creatine + phosphocreatine (Cre) was measured in left-sided frontal lobe and central posterior cingulate regions. The frontal voxel was positioned to overlap with patient-specific activation on a 1-back working memory task. RESULTS Increased GABA/Cre was shown in the frontal lobe for the concussed group. A decreased relationship was observed in the parietal region. High correlations between GABA/Cre and task activation were observed for the control group in the frontal lobe, a relationship not shown in the concussed participants. CONCLUSIONS GABA/Cre appears increased in a region colocalized with working memory task activation after sport concussion. Further work extending these results in larger samples and at time points across the injury episode will aid in refining the clinical significance of these observations.
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Affiliation(s)
- Seth D Friedman
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Andrew V Poliakov
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Christopher Budech
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Dennis W W Shaw
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - David Breiger
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Thomas Jinguji
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Brian Krabak
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - David Coppel
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Tressa Mattioli Lewis
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Samuel Browd
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle
| | - Jeffrey G Ojemann
- From the Seattle Children's Hospital and Research Institute (S.D.F., A.V.P., C.B., D.W.W.S., D.B., T.J., B.K., D.C, T.M.L., S.B., J.G.O.) and University of Washington (D.W.W.S., D.B., T.J., B.K., D.C., S.B., J.G.O.), Seattle.
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50
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Klett NJ, Allen CN. Intracellular Chloride Regulation in AVP+ and VIP+ Neurons of the Suprachiasmatic Nucleus. Sci Rep 2017; 7:10226. [PMID: 28860458 PMCID: PMC5579040 DOI: 10.1038/s41598-017-09778-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/28/2017] [Indexed: 12/15/2022] Open
Abstract
Several reports have described excitatory GABA transmission in the suprachiasmatic nucleus (SCN), the master pacemaker of circadian physiology. However, there is disagreement regarding the prevalence, timing, and neuronal location of excitatory GABA transmission in the SCN. Whether GABA is inhibitory or excitatory depends, in part, on the intracellular concentration of chloride ([Cl-]i). Here, using ratiometric Cl- imaging, we have investigated intracellular chloride regulation in AVP and VIP-expressing SCN neurons and found evidence suggesting that [Cl-]i is higher during the day than during the night in both AVP+ and VIP+ neurons. We then investigated the contribution of the cation chloride cotransporters to setting [Cl-]i in these SCN neurons and found that the chloride uptake transporter NKCC1 contributes to [Cl-]i regulation in SCN neurons, but that the KCCs are the primary regulators of [Cl-]i in SCN neurons. Interestingly, we observed that [Cl-]i is differentially regulated between AVP+ and VIP+ neurons-a low concentration of the loop diuretic bumetanide had differential effects on AVP+ and VIP+ neurons, while blocking the KCCs with VU0240551 had a larger effect on VIP+ neurons compared to AVP+ neurons.
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Affiliation(s)
- Nathan J Klett
- Neuroscience Graduate Program, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
- Oregon Institute for Occupational Health Sciences, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Charles N Allen
- Oregon Institute for Occupational Health Sciences, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.
- Department of Behavioral Neuroscience, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.
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