101
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Patton AP, Edwards MD, Smyllie NJ, Hamnett R, Chesham JE, Brancaccio M, Maywood ES, Hastings MH. The VIP-VPAC2 neuropeptidergic axis is a cellular pacemaking hub of the suprachiasmatic nucleus circadian circuit. Nat Commun 2020; 11:3394. [PMID: 32636383 PMCID: PMC7341843 DOI: 10.1038/s41467-020-17110-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 06/05/2020] [Indexed: 12/01/2022] Open
Abstract
The hypothalamic suprachiasmatic nuclei (SCN) are the principal mammalian circadian timekeeper, co-ordinating organism-wide daily and seasonal rhythms. To achieve this, cell-autonomous circadian timing by the ~20,000 SCN cells is welded into a tight circuit-wide ensemble oscillation. This creates essential, network-level emergent properties of precise, high-amplitude oscillation with tightly defined ensemble period and phase. Although synchronised, regional cell groups exhibit differentially phased activity, creating stereotypical spatiotemporal circadian waves of cellular activation across the circuit. The cellular circuit pacemaking components that generate these critical emergent properties are unknown. Using intersectional genetics and real-time imaging, we show that SCN cells expressing vasoactive intestinal polypeptide (VIP) or its cognate receptor, VPAC2, are neurochemically and electrophysiologically distinct, but together they control de novo rhythmicity, setting ensemble period and phase with circuit-level spatiotemporal complexity. The VIP/VPAC2 cellular axis is therefore a neurochemically and topologically specific pacemaker hub that determines the emergent properties of the SCN timekeeper. Circadian activity modulation in the suprachiasmatic nucleus (SCN) is a network-level emergent property that requires neuropeptide VIP signaling, yet the precise cellular mechanisms are unknown. Patton et al. show that cells expressing VIP or its receptor VPAC2 together determine these emergent properties of the SCN.
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Affiliation(s)
- Andrew P Patton
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Mathew D Edwards
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.,UCL Sainsbury Wellcome Centre for Neural Circuits and Behaviour, London, UK
| | - Nicola J Smyllie
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Ryan Hamnett
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.,Department of Neurosurgery, Stanford University, Stanford, USA
| | - Johanna E Chesham
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Marco Brancaccio
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.,Department of Brain Sciences, UK Dementia Research Institute, Imperial College London, London, UK
| | - Elizabeth S Maywood
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Michael H Hastings
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.
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102
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Calcium-induced calcium release and type 3 ryanodine receptors modulate the slow afterhyperpolarising current, sIAHP, and its potentiation in hippocampal pyramidal neurons. PLoS One 2020; 15:e0230465. [PMID: 32559219 PMCID: PMC7304577 DOI: 10.1371/journal.pone.0230465] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/03/2020] [Indexed: 12/21/2022] Open
Abstract
The slow afterhyperpolarising current, sIAHP, is a Ca2+-dependent current that plays an important role in the late phase of spike frequency adaptation. sIAHP is activated by voltage-gated Ca2+ channels, while the contribution of calcium from ryanodine-sensitive intracellular stores, released by calcium-induced calcium release (CICR), is controversial in hippocampal pyramidal neurons. Three types of ryanodine receptors (RyR1-3) are expressed in the hippocampus, with RyR3 showing a predominant expression in CA1 neurons. We investigated the specific role of CICR, and particularly of its RyR3-mediated component, in the regulation of the sIAHP amplitude and time course, and the activity-dependent potentiation of the sIAHP in rat and mouse CA1 pyramidal neurons. Here we report that enhancement of CICR by caffeine led to an increase in sIAHP amplitude, while inhibition of CICR by ryanodine caused a small, but significant reduction of sIAHP. Inhibition of ryanodine-sensitive Ca2+ stores by ryanodine or depletion by the SERCA pump inhibitor cyclopiazonic acid caused a substantial attenuation in the sIAHP activity-dependent potentiation in both rat and mouse CA1 pyramidal neurons. Neurons from mice lacking RyR3 receptors exhibited a sIAHP with features undistinguishable from wild-type neurons, which was similarly reduced by ryanodine. However, the lack of RyR3 receptors led to a faster and reduced activity-dependent potentiation of sIAHP. We conclude that ryanodine receptor-mediated CICR contributes both to the amplitude of the sIAHP at steady state and its activity-dependent potentiation in rat and mouse hippocampal pyramidal neurons. In particular, we show that RyR3 receptors play an essential and specific role in shaping the activity-dependent potentiation of the sIAHP. The modulation of activity-dependent potentiation of sIAHP by RyR3-mediated CICR contributes to plasticity of intrinsic neuronal excitability and is likely to play a critical role in higher cognitive functions, such as learning and memory.
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103
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Galloni AR, Laffere A, Rancz E. Apical length governs computational diversity of layer 5 pyramidal neurons. eLife 2020; 9:e55761. [PMID: 32463356 PMCID: PMC7334021 DOI: 10.7554/elife.55761] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022] Open
Abstract
Anatomical similarity across the neocortex has led to the common assumption that the circuitry is modular and performs stereotyped computations. Layer 5 pyramidal neurons (L5PNs) in particular are thought to be central to cortical computation because of their extensive arborisation and nonlinear dendritic operations. Here, we demonstrate that computations associated with dendritic Ca2+ plateaus in mouse L5PNs vary substantially between the primary and secondary visual cortices. L5PNs in the secondary visual cortex show reduced dendritic excitability and smaller propensity for burst firing. This reduced excitability is correlated with shorter apical dendrites. Using numerical modelling, we uncover a universal principle underlying the influence of apical length on dendritic backpropagation and excitability, based on a Na+ channel-dependent broadening of backpropagating action potentials. In summary, we provide new insights into the modulation of dendritic excitability by apical dendrite length and show that the operational repertoire of L5PNs is not universal throughout the brain.
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Affiliation(s)
- Alessandro R Galloni
- The Francis Crick InstituteLondonUnited Kingdom
- University College LondonLondonUnited Kingdom
| | - Aeron Laffere
- The Francis Crick InstituteLondonUnited Kingdom
- Birkbeck College, University of LondonLondonUnited Kingdom
| | - Ede Rancz
- The Francis Crick InstituteLondonUnited Kingdom
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104
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Switacz VK, Wypysek SK, Degen R, Crassous JJ, Spehr M, Richtering W. Influence of Size and Cross-Linking Density of Microgels on Cellular Uptake and Uptake Kinetics. Biomacromolecules 2020; 21:4532-4544. [DOI: 10.1021/acs.biomac.0c00478] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Victoria K. Switacz
- Department of Chemosensation, Institute of Biology II, RWTH Aachen University, 52056 Aachen, Germany
| | - Sarah K. Wypysek
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - Rudolf Degen
- Department of Chemosensation, Institute of Biology II, RWTH Aachen University, 52056 Aachen, Germany
| | - Jérôme J. Crassous
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute of Biology II, RWTH Aachen University, 52056 Aachen, Germany
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
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105
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Miguez-Cabello F, Sánchez-Fernández N, Yefimenko N, Gasull X, Gratacòs-Batlle E, Soto D. AMPAR/TARP stoichiometry differentially modulates channel properties. eLife 2020; 9:53946. [PMID: 32452760 PMCID: PMC7299370 DOI: 10.7554/elife.53946] [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: 11/25/2019] [Accepted: 05/24/2020] [Indexed: 11/15/2022] Open
Abstract
AMPARs control fast synaptic communication between neurons and their function relies on auxiliary subunits, which importantly modulate channel properties. Although it has been suggested that AMPARs can bind to TARPs with variable stoichiometry, little is known about the effect that this stoichiometry exerts on certain AMPAR properties. Here we have found that AMPARs show a clear stoichiometry-dependent modulation by the prototypical TARP γ2 although the receptor still needs to be fully saturated with γ2 to show some typical TARP-induced characteristics (i.e. an increase in channel conductance). We also uncovered important differences in the stoichiometric modulation between calcium-permeable and calcium-impermeable AMPARs. Moreover, in heteromeric AMPARs, γ2 positioning in the complex is important to exert certain TARP-dependent features. Finally, by comparing data from recombinant receptors with endogenous AMPAR currents from mouse cerebellar granule cells, we have determined a likely presence of two γ2 molecules at somatic receptors in this cell type.
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Affiliation(s)
- Federico Miguez-Cabello
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Nuria Sánchez-Fernández
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Natalia Yefimenko
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Esther Gratacòs-Batlle
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - David Soto
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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106
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Alpert MH, Frank DD, Kaspi E, Flourakis M, Zaharieva EE, Allada R, Para A, Gallio M. A Circuit Encoding Absolute Cold Temperature in Drosophila. Curr Biol 2020; 30:2275-2288.e5. [PMID: 32442464 DOI: 10.1016/j.cub.2020.04.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/31/2020] [Accepted: 04/16/2020] [Indexed: 11/28/2022]
Abstract
Animals react to environmental changes over timescales ranging from seconds to days and weeks. An important question is how sensory stimuli are parsed into neural signals operating over such diverse temporal scales. Here, we uncover a specialized circuit, from sensory neurons to higher brain centers, that processes information about long-lasting, absolute cold temperature in Drosophila. We identify second-order thermosensory projection neurons (TPN-IIs) exhibiting sustained firing that scales with absolute temperature. Strikingly, this activity only appears below the species-specific, preferred temperature for D. melanogaster (∼25°C). We trace the inputs and outputs of TPN-IIs and find that they are embedded in a cold "thermometer" circuit that provides powerful and persistent inhibition to brain centers involved in regulating sleep and activity. Our results demonstrate that the fly nervous system selectively encodes and relays absolute temperature information and illustrate a sensory mechanism that allows animals to adapt behavior specifically to cold conditions on the timescale of hours to days.
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Affiliation(s)
- Michael H Alpert
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Dominic D Frank
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Evan Kaspi
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Matthieu Flourakis
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | | | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Alessia Para
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Marco Gallio
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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107
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Sadanandan SM, Kreko-Pierce T, Khatri SN, Pugh JR. Cannabinoid type 2 receptors inhibit GABAA receptor-mediated currents in cerebellar Purkinje cells of juvenile mice. PLoS One 2020; 15:e0233020. [PMID: 32437355 PMCID: PMC7241750 DOI: 10.1371/journal.pone.0233020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 04/28/2020] [Indexed: 12/15/2022] Open
Abstract
Signaling through the endocannabinoid system is critical to proper functioning of the cerebellar circuit. However, most studies have focused on signaling through cannabinoid type 1 (CB1) receptors, while relatively little is known about signaling through type 2 (CB2) receptors. We show that functional CB2 receptors are expressed in Purkinje cells using a combination of immunohistochemistry and patch-clamp electrophysiology in juvenile mice. Pharmacological activation of CB2 receptors significantly reduces inhibitory synaptic responses and currents mediated by photolytic uncaging of RuBi-GABA in Purkinje cells. CB2 receptor activation does not change the paired-pulse ratio of inhibitory responses and its effects are blocked by inclusion of GDP-β-S in the internal solution, indicating a postsynaptic mechanism of action. However, CB2 receptors do not contribute to depolarization induced suppression of inhibition (DSI), indicating they are not activated by endocannabinoids synthesized and released from Purkinje cells using this protocol. This work demonstrates that CB2 receptors inhibit postsynaptic GABAA receptors by a postsynaptic mechanism in Purkinje cells. This represents a novel mechanism by which CB2 receptors may modulate neuronal and circuit function in the central nervous system.
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Affiliation(s)
- Sriity Melley Sadanandan
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Tabita Kreko-Pierce
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Shailesh N. Khatri
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Jason R. Pugh
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
- Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
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108
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Pan-Vazquez A, Wefelmeyer W, Gonzalez Sabater V, Neves G, Burrone J. Activity-Dependent Plasticity of Axo-axonic Synapses at the Axon Initial Segment. Neuron 2020; 106:265-276.e6. [PMID: 32109363 PMCID: PMC7181187 DOI: 10.1016/j.neuron.2020.01.037] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 12/06/2019] [Accepted: 01/27/2020] [Indexed: 12/20/2022]
Abstract
The activity-dependent rules that govern the wiring of GABAergic interneurons are not well understood. Chandelier cells (ChCs) are a type of GABAergic interneuron that control pyramidal cell output through axo-axonic synapses that target the axon initial segment. In vivo imaging of ChCs during development uncovered a narrow window (P12-P18) over which axons arborized and formed connections. We found that increases in the activity of either pyramidal cells or individual ChCs during this temporal window result in a reversible decrease in axo-axonic connections. Voltage imaging of GABAergic transmission at the axon initial segment (AIS) showed that axo-axonic synapses were depolarizing during this period. Identical manipulations of network activity in older mice (P40-P46), when ChC synapses are inhibitory, resulted instead in an increase in axo-axonic synapses. We propose that the direction of ChC synaptic plasticity follows homeostatic rules that depend on the polarity of axo-axonic synapses.
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Affiliation(s)
- Alejandro Pan-Vazquez
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Winnie Wefelmeyer
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Victoria Gonzalez Sabater
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Guilherme Neves
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0FA, UK
| | - Juan Burrone
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK.
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109
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Structural basis of astrocytic Ca 2+ signals at tripartite synapses. Nat Commun 2020; 11:1906. [PMID: 32312988 PMCID: PMC7170846 DOI: 10.1038/s41467-020-15648-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. However, the anatomical basis of such specific signaling remains unclear, owing to difficulties in resolving the spongiform domain of astrocytes where most tripartite synapses are located. Using 3D-STED microscopy in living organotypic brain slices, we imaged the spongiform domain of astrocytes and observed a reticular meshwork of nodes and shafts that often formed loop-like structures. These anatomical features were also observed in acute hippocampal slices and in barrel cortex in vivo. The majority of dendritic spines were contacted by nodes and their sizes were correlated. FRAP experiments and Ca2+ imaging showed that nodes were biochemical compartments and Ca2+ microdomains. Mapping astrocytic Ca2+ signals onto STED images of nodes and dendritic spines showed they were associated with individual synapses. Here, we report on the nanoscale organization of astrocytes, identifying nodes as a functional astrocytic component of tripartite synapses that may enable synapse-specific communication between neurons and astrocytes. Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. Here, the authors report the organization of astrocytes at nanoscale level and identify nodes as a functional astrocytic component of tripartite synapses.
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110
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A VTA to Basal Amygdala Dopamine Projection Contributes to Signal Salient Somatosensory Events during Fear Learning. J Neurosci 2020; 40:3969-3980. [PMID: 32277045 DOI: 10.1523/jneurosci.1796-19.2020] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 01/02/2023] Open
Abstract
The amygdala is a brain area critical for the formation of fear memories. However, the nature of the teaching signal(s) that drive plasticity in the amygdala are still under debate. Here, we use optogenetic methods to investigate the contribution of ventral tegmental area (VTA) dopamine neurons to auditory-cued fear learning in male mice. Using anterograde and retrograde labeling, we found that a sparse and relatively evenly distributed population of VTA neurons projects to the basal amygdala (BA). In vivo optrode recordings in behaving mice showed that many VTA neurons, among them putative dopamine neurons, are excited by footshocks, and acquire a response to auditory stimuli during fear learning. Combined cfos imaging and retrograde labeling in dopamine transporter (DAT) Cre mice revealed that a large majority of BA projectors (>95%) are dopamine neurons, and that BA projectors become activated by the tone-footshock pairing of fear learning protocols. Finally, silencing VTA dopamine neurons, or their axon terminals in the BA during the footshock, reduced the strength of fear memory as tested 1 d later, whereas silencing the VTA-central amygdala (CeA) projection had no effect. Thus, VTA dopamine neurons projecting to the BA contribute to fear memory formation, by coding for the saliency of the footshock event and by signaling such events to the basal amygdala.SIGNIFICANCE STATEMENT Powerful mechanisms of fear learning have evolved in animals and humans to enable survival. During fear conditioning, a sensory cue, such as a tone (the conditioned stimulus), comes to predict an innately aversive stimulus, such as a mild footshock (the unconditioned stimulus). A brain representation of the unconditioned stimulus must act as a teaching signal to instruct plasticity of the conditioned stimulus representation in fear-related brain areas. Here we show that dopamine neurons in the VTA that project to the basal amygdala contribute to such a teaching signal for plasticity, thereby facilitating the formation of fear memories. Knowledge about the role of dopamine in aversively motivated plasticity might allow further insights into maladaptive plasticities that underlie anxiety and post-traumatic stress disorders in humans.
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111
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DeCosta-Fortune TM, Ramshur JT, Li CX, de Jongh Curry A, Pellicer-Morata V, Wang L, Waters RS. Repetitive microstimulation in rat primary somatosensory cortex (SI) strengthens the connection between homotopic sites in the opposite SI and leads to expression of previously ineffective input from the ipsilateral forelimb. Brain Res 2020; 1732:146694. [PMID: 32017899 PMCID: PMC7237062 DOI: 10.1016/j.brainres.2020.146694] [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: 01/24/2018] [Revised: 01/06/2020] [Accepted: 01/29/2020] [Indexed: 10/25/2022]
Abstract
The primary somatosensory cortex (SI) receives input from the contralateral forelimb and projects to homotopic sites in the opposite SI. Since homotopic sites in SI are linked by a callosal pathway, we proposed that repetitive intracortical microstimulation (ICMSr) of neurons in layer V of SI forelimb cortex would increase spike firing in the opposite SI cortex thereby strengthening the callosal pathway sufficiently to allow normally ineffective stimuli from the ipsilateral forelimb to excite cells in the ipsilateral SI. The forelimb representation in SI in one hemisphere was mapped using mechanical and electrical stimulation of the contralateral forelimb, a homotopic site was similarly identified in the opposite SI, the presence of ipsilateral peripheral input was tested in both homotopic sites, and ICMS was used to establish an interhemispheric connection between the two homotopic recording sites. The major findings are: (1) each homotopic forelimb site in SI initially received short latency input only from the contralateral forelimb; (2) homotopic sites in layer V in each SI were interconnected by a callosal pathway; (3) ICMSr delivered to layer V of the homotopic SI in one hemisphere generally increased evoked response spike firing in layer V in the opposite homotopic site; (4) increased spike firing was often followed by the expression of a longer latency normally ineffective input from the ipsilateral forelimb; (5) these longer latency ipsilateral responses are consistent with a delay time sufficient to account for travel across the callosal pathway; (6) increased spike firing and the resulting ipsilateral peripheral input were also corroborated using in-vivo intracellular recording; and (7) inactivation of the stimulating site in SI by lidocaine injection or local surface cooling abolished the ipsilateral response, suggesting that the ipsilateral response was very likely relayed across the callosal pathway. These results suggest that repetitive microstimulation can do more than expand receptive fields in the territory adjacent to the stimulating electrode but in addition can also alter receptive fields in homotopic sites in the opposite SI to bring about the expression of previously ineffective input from the ipsilateral forelimb.
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Affiliation(s)
- Tina M DeCosta-Fortune
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - John T Ramshur
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - Cheng X Li
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - Violeta Pellicer-Morata
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Lie Wang
- Department of Neurology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Robert S Waters
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA.
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112
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Falck J, Bruns C, Hoffmann-Conaway S, Straub I, Plautz EJ, Orlando M, Munawar H, Rivalan M, Winter Y, Izsvák Z, Schmitz D, Hamra FK, Hallermann S, Garner CC, Ackermann F. Loss of Piccolo Function in Rats Induces Cerebellar Network Dysfunction and Pontocerebellar Hypoplasia Type 3-like Phenotypes. J Neurosci 2020; 40:2943-2959. [PMID: 32122952 PMCID: PMC7117892 DOI: 10.1523/jneurosci.2316-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 12/16/2022] Open
Abstract
Piccolo, a presynaptic active zone protein, is best known for its role in the regulated assembly and function of vertebrate synapses. Genetic studies suggest a further link to several psychiatric disorders as well as Pontocerebellar Hypoplasia type 3 (PCH3). We have characterized recently generated Piccolo KO (Pclogt/gt ) rats. Analysis of rats of both sexes revealed a dramatic reduction in brain size compared with WT (Pclowt/wt ) animals, attributed to a decrease in the size of the cerebral cortical, cerebellar, and pontine regions. Analysis of the cerebellum and brainstem revealed a reduced granule cell layer and a reduction in size of pontine nuclei. Moreover, the maturation of mossy fiber afferents from pontine neurons and the expression of the α6 GABAA receptor subunit at the mossy fiber-granule cell synapse are perturbed, as well as the innervation of Purkinje cells by cerebellar climbing fibers. Ultrastructural and functional studies revealed a reduced size of mossy fiber boutons, with fewer synaptic vesicles and altered synaptic transmission. These data imply that Piccolo is required for the normal development, maturation, and function of neuronal networks formed between the brainstem and cerebellum. Consistently, behavioral studies demonstrated that adult Pclogt/gt rats display impaired motor coordination, despite adequate performance in tasks that reflect muscle strength and locomotion. Together, these data suggest that loss of Piccolo function in patients with PCH3 could be involved in many of the observed anatomical and behavioral symptoms, and that the further analysis of these animals could provide fundamental mechanistic insights into this devastating disorder.SIGNIFICANCE STATEMENT Pontocerebellar Hypoplasia Type 3 is a devastating developmental disorder associated with severe developmental delay, progressive microcephaly with brachycephaly, optic atrophy, seizures, and hypertonia with hyperreflexia. Recent genetic studies have identified non-sense mutations in the coding region of the PCLO gene, suggesting a functional link between this disorder and the presynaptic active zone. Our analysis of Piccolo KO rats supports this hypothesis, formally demonstrating that anatomical and behavioral phenotypes seen in patients with Pontocerebellar Hypoplasia Type 3 are also exhibited by these Piccolo deficient animals.
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Affiliation(s)
- Joanne Falck
- German Center for Neurodegenerative Diseases, Charité Medical University, 10117 Berlin, Germany
| | - Christine Bruns
- German Center for Neurodegenerative Diseases, Charité Medical University, 10117 Berlin, Germany
| | - Sheila Hoffmann-Conaway
- German Center for Neurodegenerative Diseases, Charité Medical University, 10117 Berlin, Germany
| | - Isabelle Straub
- Carl-Ludwig Institute for Physiology, 04103 Leipzig, Germany
| | - Erik J Plautz
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, Texas 75390
| | - Marta Orlando
- Charité Medical University Berlin and Berlin Institute of Health, NeuroCure Cluster of Excellence, 10117 Berlin, Germany
| | - Humaira Munawar
- Department of Biology, Humboldt University, 10099 Berlin, Germany
| | - Marion Rivalan
- Charité Medical University Berlin and Berlin Institute of Health, NeuroCure Cluster of Excellence, 10117 Berlin, Germany
- Department of Biology, Humboldt University, 10099 Berlin, Germany
| | - York Winter
- Charité Medical University Berlin and Berlin Institute of Health, NeuroCure Cluster of Excellence, 10117 Berlin, Germany
- Department of Biology, Humboldt University, 10099 Berlin, Germany
| | - Zsuzsanna Izsvák
- Max Delbrück Center for Molecular Medicine in the Helmholtz Society, 13125 Berlin, Germany, and
| | - Dietmar Schmitz
- Charité Medical University Berlin and Berlin Institute of Health, NeuroCure Cluster of Excellence, 10117 Berlin, Germany
| | - F Kent Hamra
- Department of Obstetrics and Gynecology, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern, Dallas, Texas 75390
| | | | - Craig Curtis Garner
- German Center for Neurodegenerative Diseases, Charité Medical University, 10117 Berlin, Germany
| | - Frauke Ackermann
- German Center for Neurodegenerative Diseases, Charité Medical University, 10117 Berlin, Germany,
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Riva M, Genescu I, Habermacher C, Orduz D, Ledonne F, Rijli FM, López-Bendito G, Coppola E, Garel S, Angulo MC, Pierani A. Activity-dependent death of transient Cajal-Retzius neurons is required for functional cortical wiring. eLife 2019; 8:50503. [PMID: 31891351 PMCID: PMC6938399 DOI: 10.7554/elife.50503] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/06/2019] [Indexed: 12/19/2022] Open
Abstract
Programmed cell death and early activity contribute to the emergence of functional cortical circuits. While most neuronal populations are scaled-down by death, some subpopulations are entirely eliminated, raising the question of the importance of such demise for cortical wiring. Here, we addressed this issue by focusing on Cajal-Retzius neurons (CRs), key players in cortical development that are eliminated in postnatal mice in part via Bax-dependent apoptosis. Using Bax-conditional mutants and CR hyperpolarization, we show that the survival of electrically active subsets of CRs triggers an increase in both dendrite complexity and spine density of upper layer pyramidal neurons, leading to an excitation/inhibition imbalance. The survival of these CRs is induced by hyperpolarization, highlighting an interplay between early activity and neuronal elimination. Taken together, our study reveals a novel activity-dependent programmed cell death process required for the removal of transient immature neurons and the proper wiring of functional cortical circuits.
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Affiliation(s)
- Martina Riva
- Institut Imagine, Université de Paris, Paris, France.,Institut Jacques Monod, CNRS UMR 7592, Université de Paris, Paris, France.,Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Université de Paris, Paris, France
| | - Ioana Genescu
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Chloé Habermacher
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Université de Paris, Paris, France.,INSERM U1128, Paris, France
| | | | - Fanny Ledonne
- Institut Jacques Monod, CNRS UMR 7592, Université de Paris, Paris, France
| | - Filippo M Rijli
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Eva Coppola
- Institut Imagine, Université de Paris, Paris, France.,Institut Jacques Monod, CNRS UMR 7592, Université de Paris, Paris, France.,Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Université de Paris, Paris, France
| | - Sonia Garel
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Maria Cecilia Angulo
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Université de Paris, Paris, France.,INSERM U1128, Paris, France
| | - Alessandra Pierani
- Institut Imagine, Université de Paris, Paris, France.,Institut Jacques Monod, CNRS UMR 7592, Université de Paris, Paris, France.,Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Université de Paris, Paris, France
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114
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Vandrey B, Garden DLF, Ambrozova V, McClure C, Nolan MF, Ainge JA. Fan Cells in Layer 2 of the Lateral Entorhinal Cortex Are Critical for Episodic-like Memory. Curr Biol 2019; 30:169-175.e5. [PMID: 31839450 PMCID: PMC6947484 DOI: 10.1016/j.cub.2019.11.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/11/2019] [Accepted: 11/07/2019] [Indexed: 11/28/2022]
Abstract
Episodic memory requires different types of information to be bound together to generate representations of experiences. The lateral entorhinal cortex (LEC) and hippocampus are required for episodic-like memory in rodents [1, 2]. The LEC is critical for integrating spatial and contextual information about objects [2, 3, 4, 5, 6]. Further, LEC neurons encode objects in the environment and the locations where objects were previously experienced and generate representations of time during the encoding and retrieval of episodes [7, 8, 9, 10, 11, 12]. However, it remains unclear how specific populations of cells within the LEC contribute to the integration of episodic memory components. Layer 2 (L2) of LEC manifests early pathology in Alzheimer’s disease (AD) and related animal models [13, 14, 15, 16]. Projections to the hippocampus from L2 of LEC arise from fan cells in a superficial sub-layer (L2a) that are immunoreactive for reelin and project to the dentate gyrus [17, 18]. Here, we establish an approach for selectively targeting fan cells using Sim1:Cre mice. Whereas complete lesions of the LEC were previously found to abolish associative recognition memory [2, 3], we report that, after selective suppression of synaptic output from fan cells, mice can discriminate novel object-context configurations but are impaired in recognition of novel object-place-context associations. Our results suggest that memory functions are segregated between distinct LEC networks. Sim1:Cre mice provide access to DG-projecting fan cells in lateral entorhinal cortex Fan cells are not required for novel object or object-context recognition Fan cells are required to discriminate novel object-place-context configurations Episodic-like memory impairment is correlated with extent of fan-cell inactivation
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Affiliation(s)
- Brianna Vandrey
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XE, Scotland; School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews KY16 9JP, Scotland
| | - Derek L F Garden
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XE, Scotland
| | - Veronika Ambrozova
- School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews KY16 9JP, Scotland
| | - Christina McClure
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XE, Scotland
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XE, Scotland.
| | - James A Ainge
- School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews KY16 9JP, Scotland.
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115
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Contini D, Holstein GR, Art JJ. Synaptic cleft microenvironment influences potassium permeation and synaptic transmission in hair cells surrounded by calyx afferents in the turtle. J Physiol 2019; 598:853-889. [PMID: 31623011 DOI: 10.1113/jp278680] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/13/2019] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS In central regions of vestibular semicircular canal epithelia, the [K+ ] in the synaptic cleft ([K+ ]c ) contributes to setting the hair cell and afferent membrane potentials; the potassium efflux from type I hair cells results from the interdependent gating of three conductances. Elevation of [K+ ]c occurs through a calcium-activated potassium conductance, GBK , and a low-voltage-activating delayed rectifier, GK(LV) , that activates upon elevation of [K+ ]c . Calcium influx that enables quantal transmission also activates IBK , an effect that can be blocked internally by BAPTA, and externally by a CaV 1.3 antagonist or iberiotoxin. Elevation of [K+ ]c or chelation of [Ca2+ ]c linearizes the GK(LV) steady-state I-V curve, suggesting that the outward rectification observed for GK(LV) may result largely from a potassium-sensitive relief of Ca2+ inactivation of the channel pore selectivity filter. Potassium sensitivity of hair cell and afferent conductances allows three modes of transmission: quantal, ion accumulation and resistive coupling to be multiplexed across the synapse. ABSTRACT In the vertebrate nervous system, ions accumulate in diffusion-limited synaptic clefts during ongoing activity. Such accumulation can be demonstrated at large appositions such as the hair cell-calyx afferent synapses present in central regions of the turtle vestibular semicircular canal epithelia. Type I hair cells influence discharge rates in their calyx afferents by modulating the potassium concentration in the synaptic cleft, [K+ ]c , which regulates potassium-sensitive conductances in both hair cell and afferent. Dual recordings from synaptic pairs have demonstrated that, despite a decreased driving force due to potassium accumulation, hair cell depolarization elicits sustained outward currents in the hair cell, and a maintained inward current in the afferent. We used kinetic and pharmacological dissection of the hair cell conductances to understand the interdependence of channel gating and permeation in the context of such restricted extracellular spaces. Hair cell depolarization leads to calcium influx and activation of a large calcium-activated potassium conductance, GBK , that can be blocked by agents that disrupt calcium influx or buffer the elevation of [Ca2+ ]i , as well as by the specific KCa 1.1 blocker iberiotoxin. Efflux of K+ through GBK can rapidly elevate [K+ ]c , which speeds the activation and slows the inactivation and deactivation of a second potassium conductance, GK(LV) . Elevation of [K+ ]c or chelation of [Ca2+ ]c linearizes the GK(LV) steady-state I-V curve, consistent with a K+ -dependent relief of Ca2+ inactivation of GK(LV) . As a result, this potassium-sensitive hair cell conductance pairs with the potassium-sensitive hyperpolarization-activated cyclic nucleotide-gated channel (HCN) conductance in the afferent and creates resistive coupling at the synaptic cleft.
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Affiliation(s)
- Donatella Contini
- Department of Anatomy & Cell Biology, University of Illinois College of Medicine, 808 S. Wood St, Chicago, IL, 60612, USA
| | - Gay R Holstein
- Neurology, Icahn School of Medicine at Mount Sinai, 1468 Madison Ave, New York, NY, 10029, USA
| | - Jonathan J Art
- Department of Anatomy & Cell Biology, University of Illinois College of Medicine, 808 S. Wood St, Chicago, IL, 60612, USA
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Mechanisms of GABA B receptor enhancement of extrasynaptic GABA A receptor currents in cerebellar granule cells. Sci Rep 2019; 9:16683. [PMID: 31723152 PMCID: PMC6853962 DOI: 10.1038/s41598-019-53087-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/26/2019] [Indexed: 12/31/2022] Open
Abstract
Many neurons, including cerebellar granule cells, exhibit a tonic GABA current mediated by extrasynaptic GABAA receptors. This current is a critical regulator of firing and the target of many clinically relevant compounds. Using a combination of patch clamp electrophysiology and photolytic uncaging of RuBi-GABA we show that GABAB receptors are tonically active and enhance extrasynaptic GABAA receptor currents in cerebellar granule cells. This enhancement is not associated with meaningful changes in GABAA receptor potency, mean channel open-time, open probability, or single-channel current. However, there was a significant (~40%) decrease in the number of channels participating in the GABA uncaging current and an increase in receptor desensitization. Furthermore, we find that adenylate cyclase, PKA, CaMKII, and release of Ca2+ from intracellular stores are necessary for modulation of GABAA receptors. Overall, this work reveals crosstalk between postsynaptic GABAA and GABAB receptors and identifies the signaling pathways and mechanisms involved.
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117
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Karube F, Takahashi S, Kobayashi K, Fujiyama F. Motor cortex can directly drive the globus pallidus neurons in a projection neuron type-dependent manner in the rat. eLife 2019; 8:e49511. [PMID: 31711567 PMCID: PMC6863630 DOI: 10.7554/elife.49511] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/29/2019] [Indexed: 12/14/2022] Open
Abstract
The basal ganglia are critical for the control of motor behaviors and for reinforcement learning. Here, we demonstrate in rats that primary and secondary motor areas (M1 and M2) make functional synaptic connections in the globus pallidus (GP), not usually thought of as an input site of the basal ganglia. Morphological observation revealed that the density of axonal boutons from motor cortices in the GP was 47% and 78% of that in the subthalamic nucleus (STN) from M1 and M2, respectively. Cortical excitation of GP neurons was comparable to that of STN neurons in slice preparations. FoxP2-expressing arkypallidal neurons were preferentially innervated by the motor cortex. The connection probability of cortico-pallidal innervation was higher for M2 than M1. These results suggest that cortico-pallidal innervation is an additional excitatory input to the basal ganglia, and that it can affect behaviors via the cortex-basal ganglia-thalamus motor loop.
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Affiliation(s)
- Fuyuki Karube
- Laboratory of Neural Circuitry, Graduate School of Brain ScienceDoshisha UniversityKyotanabeJapan
| | - Susumu Takahashi
- Laboratory of Neural Circuitry, Graduate School of Brain ScienceDoshisha UniversityKyotanabeJapan
- Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Brain ScienceDoshisha UniversityKyotanabeJapan
| | - Kenta Kobayashi
- Section of Viral Vector DevelopmentNational Institute for Physiological SciencesOkazakiJapan
| | - Fumino Fujiyama
- Laboratory of Neural Circuitry, Graduate School of Brain ScienceDoshisha UniversityKyotanabeJapan
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118
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Nakamura Y. EGTA Can Inhibit Vesicular Release in the Nanodomain of Single Ca 2+ Channels. Front Synaptic Neurosci 2019; 11:26. [PMID: 31632263 PMCID: PMC6779814 DOI: 10.3389/fnsyn.2019.00026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/02/2019] [Indexed: 01/21/2023] Open
Abstract
The exogenous Ca2+ chelator EGTA (ethylene glycol tetraacetic acid) has been widely used to probe the coupling distance between Ca2+ channels and vesicular Ca2+ sensors for neurotransmitter release. Because of its slow forward rate for binding, EGTA is thought to not capture calcium ions in very proximity to a channel, whereas it does capture calcium ions at the remote distance. However, in this study, our reaction diffusion simulations (RDSs) of Ca2+ combined with a release calculation using vesicular sensor models indicate that a high concentration of EGTA decreases Ca2+ and vesicular release in the nanodomain of single channels. We found that a key determinant of the effect of EGTA on neurotransmitter release is the saturation of the vesicular sensor. When the sensor is saturated, the reduction in the Ca2+ concentration by EGTA is masked. By contrast, when the sensor is in a linear range, even a small reduction in Ca2+ by EGTA can decrease vesicular release. In proximity to a channel, the vesicular sensor is often saturated for a long voltage step, but not for a brief Ca2+ influx typically evoked by an action potential. Therefore, when EGTA is used as a diagnostic tool to probe the coupling distance, care must be taken regarding the presynaptic Ca2+ entry duration as well as the property of the vesicular Ca2+ sensor.
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Affiliation(s)
- Yukihiro Nakamura
- Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan
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119
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Adaptive disinhibitory gating by VIP interneurons permits associative learning. Nat Neurosci 2019; 22:1834-1843. [DOI: 10.1038/s41593-019-0508-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 09/05/2019] [Indexed: 01/19/2023]
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120
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Ueta Y, Sohn J, Agahari FA, Im S, Hirai Y, Miyata M, Kawaguchi Y. Ipsi- and contralateral corticocortical projection-dependent subcircuits in layer 2 of the rat frontal cortex. J Neurophysiol 2019; 122:1461-1472. [DOI: 10.1152/jn.00333.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the neocortex, both layer 2/3 and layer 5 contain corticocortical pyramidal cells projecting to other cortices. We previously found that among L5 pyramidal cells of the secondary motor cortex (M2), not only intratelencephalic projection cells but also pyramidal tract cells innervate ipsilateral cortices and that the two subtypes are different in corticocortical projection diversity and axonal laminar distributions. Layer 2/3 houses intratelencephalically projecting pyramidal cells that also innervate multiple ipsilateral and contralateral cortices. However, it remained unclear whether layer 2/3 pyramidal cells can be divided into projection subtypes each with distinct innervation to specific targets. In the present study we show that layer 2 pyramidal cells are organized into subcircuits on the basis of corticocortical projection targets. Layer 2 corticocortical cells of the same projection subtype were monosynaptically connected. Between the contralaterally and ipsilaterally projecting corticocortical cells, the monosynaptic connection was more common from the former to the latter. We also found that ipsilaterally and contralaterally projecting corticocortical cell subtypes differed in their morphological and physiological characteristics. Our results suggest that layer 2 transfers separate outputs from M2 to individual cortices and that its subcircuits are hierarchically organized to form the discrete corticocortical outputs. NEW & NOTEWORTHY Pyramidal cell subtypes and their dependent subcircuits are well characterized in cortical layer 5, but much less is understood for layer 2/3. We demonstrate that in layer 2 of the rat secondary motor cortex, ipsilaterally and contralaterally projecting corticocortical cells are largely segregated. These layer 2 cell subtypes differ in dendrite morphological and intrinsic electrophysiological properties, and form subtype-dependent connections. Our results suggest that layer 2 pyramidal cells form distinct subcircuits to provide discrete corticocortical outputs.
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Affiliation(s)
- Yoshifumi Ueta
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Physiology, Division of Neurophysiology, School of Medicine, Tokyo Women’s Medical University, Tokyo, Japan
| | - Jaerin Sohn
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | | | - Sanghun Im
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Physiological Sciences, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Yasuharu Hirai
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, Japan
| | - Mariko Miyata
- Department of Physiology, Division of Neurophysiology, School of Medicine, Tokyo Women’s Medical University, Tokyo, Japan
| | - Yasuo Kawaguchi
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Physiological Sciences, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
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121
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Distinct Nanoscale Calcium Channel and Synaptic Vesicle Topographies Contribute to the Diversity of Synaptic Function. Neuron 2019; 104:693-710.e9. [PMID: 31558350 DOI: 10.1016/j.neuron.2019.08.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 05/31/2019] [Accepted: 08/08/2019] [Indexed: 12/22/2022]
Abstract
The nanoscale topographical arrangement of voltage-gated calcium channels (VGCC) and synaptic vesicles (SVs) determines synaptic strength and plasticity, but whether distinct spatial distributions underpin diversity of synaptic function is unknown. We performed single bouton Ca2+ imaging, Ca2+ chelator competition, immunogold electron microscopic (EM) localization of VGCCs and the active zone (AZ) protein Munc13-1, at two cerebellar synapses. Unexpectedly, we found that weak synapses exhibited 3-fold more VGCCs than strong synapses, while the coupling distance was 5-fold longer. Reaction-diffusion modeling could explain both functional and structural data with two strikingly different nanotopographical motifs: strong synapses are composed of SVs that are tightly coupled (∼10 nm) to VGCC clusters, whereas at weak synapses VGCCs were excluded from the vicinity (∼50 nm) of docked vesicles. The distinct VGCC-SV topographical motifs also confer differential sensitivity to neuromodulation. Thus, VGCC-SV arrangements are not canonical, and their diversity could underlie functional heterogeneity across CNS synapses.
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122
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Coombs ID, Soto D, McGee TP, Gold MG, Farrant M, Cull-Candy SG. Homomeric GluA2(R) AMPA receptors can conduct when desensitized. Nat Commun 2019; 10:4312. [PMID: 31541113 PMCID: PMC6754398 DOI: 10.1038/s41467-019-12280-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 08/28/2019] [Indexed: 11/21/2022] Open
Abstract
Desensitization is a canonical property of ligand-gated ion channels, causing progressive current decline in the continued presence of agonist. AMPA-type glutamate receptors (AMPARs), which mediate fast excitatory signaling throughout the brain, exhibit profound desensitization. Recent cryo-EM studies of AMPAR assemblies show their ion channels to be closed in the desensitized state. Here we present evidence that homomeric Q/R-edited AMPARs still allow ions to flow when the receptors are desensitized. GluA2(R) expressed alone, or with auxiliary subunits (γ-2, γ-8 or GSG1L), generates large fractional steady-state currents and anomalous current-variance relationships. Our results from fluctuation analysis, single-channel recording, and kinetic modeling, suggest that the steady-state current is mediated predominantly by conducting desensitized receptors. When combined with crystallography this unique functional readout of a hitherto silent state enabled us to examine cross-linked cysteine mutants to probe the conformation of the desensitized ligand binding domain of functioning AMPAR complexes. AMPA-type glutamate receptors, which mediate fast excitatory signaling throughout the brain, exhibit profound desensitization, causing a progressive current decline in the continued presence of agonist. Here authors show that homomeric Q/R edited AMPARs still allow ions to flow when the receptors are desensitized.
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Affiliation(s)
- Ian D Coombs
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - David Soto
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.,Department of Biomedicine, Neurophysiology Laboratory, Medical School, Institute of Neurosciences, University of Barcelona, Casanova 143, 08036, Barcelona, Spain
| | - Thomas P McGee
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Matthew G Gold
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Mark Farrant
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Stuart G Cull-Candy
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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Developmental cell death regulates lineage-related interneuron-oligodendroglia functional clusters and oligodendrocyte homeostasis. Nat Commun 2019; 10:4249. [PMID: 31534164 PMCID: PMC6751198 DOI: 10.1038/s41467-019-11904-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/04/2019] [Indexed: 12/22/2022] Open
Abstract
The first wave of oligodendrocyte precursor cells (firstOPCs) and most GABAergic interneurons share common embryonic origins. Cortical firstOPCs are thought to be replaced by other OPC populations shortly after birth, maintaining a consistent OPC density and making postnatal interactions between firstOPCs and ontogenetically-related interneurons unlikely. Challenging these ideas, we show that a cortical firstOPC subpopulation survives and forms functional cell clusters with lineage-related interneurons. Favored by a common embryonic origin, these clusters display unexpected preferential synaptic connectivity and are anatomically maintained after firstOPCs differentiate into myelinating oligodendrocytes. While the concomitant rescue of interneurons and firstOPCs committed to die causes an exacerbated neuronal inhibition, it abolishes interneuron-firstOPC high synaptic connectivity. Further, the number of other oligodendroglia populations increases through a non-cell-autonomous mechanism, impacting myelination. These findings demonstrate unprecedented roles of interneuron and firstOPC apoptosis in regulating lineage-related cell interactions and the homeostatic oligodendroglia density. During cortical development the first wave of oligodendrocyte precursor cells (OPCs) completely disappear by programmed cell death, so that it is presumed that this OPC population does not play a role at postnatal stages. In this study, authors use lineage tracing in different transgenic mice to show that a subpopulation of OPCs from the first wave survives at postnatal stages and display a preferential synaptic connectivity with their ontogenetically-related interneurons compared to other OPCs or interneurons
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Ueta Y, Yamamoto R, Kato N. Layer-specific modulation of pyramidal cell excitability by electroconvulsive shock. Neurosci Lett 2019; 709:134383. [PMID: 31325579 DOI: 10.1016/j.neulet.2019.134383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/17/2019] [Accepted: 07/16/2019] [Indexed: 10/26/2022]
Abstract
Dysregulation of cortical excitability crucially involves in behavioral and cognitive deficits of neurodegenerative and neuropsychiatric diseases. Electroconvulsive shock (ECS) changes neuronal excitability and has been used in the therapy of major depressive disorder and mood disorders. However, the action and the targets of the ECS in the cortical circuits are still poorly understood. Here we show that the ECS differently changes intrinsic properties of pyramidal cells (PCs) among superficial and deep layers. In layer 2/3 PCs, the ECS induced membrane hyperpolarization and the reduction of input resistances. In layer 5 PCs, the ECS also induced membrane hyperpolarization but had little effects on input resistances. In layer 6 PCs, the ECS had no effects on both of resting membrane potentials and input resistances. In addition, the ECS reduced the firing frequency of PCs in layer 2/3 but not in both layers 5 and 6. We further examined the ECS-induced changes in the influx of Ca2+ currents, and observed an enhanced Ca2+ currents in PCs of both layers 2/3 and 5 but not of layer 6. Thus, this study suggests the layer-specific suppression of PC excitability which will underlie the mechanism of the ECS action on the cortical activity.
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Affiliation(s)
- Yoshifumi Ueta
- Department of Physiology, Division of Neurophysiology, Tokyo Women's Medical University, Tokyo 162-8666, Japan.
| | - Ryo Yamamoto
- Department of Physiology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan
| | - Nobuo Kato
- Department of Physiology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan.
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125
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Sayin S, De Backer JF, Siju KP, Wosniack ME, Lewis LP, Frisch LM, Gansen B, Schlegel P, Edmondson-Stait A, Sharifi N, Fisher CB, Calle-Schuler SA, Lauritzen JS, Bock DD, Costa M, Jefferis GSXE, Gjorgjieva J, Grunwald Kadow IC. A Neural Circuit Arbitrates between Persistence and Withdrawal in Hungry Drosophila. Neuron 2019; 104:544-558.e6. [PMID: 31471123 PMCID: PMC6839618 DOI: 10.1016/j.neuron.2019.07.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/09/2019] [Accepted: 07/22/2019] [Indexed: 01/24/2023]
Abstract
In pursuit of food, hungry animals mobilize significant energy resources and overcome exhaustion and fear. How need and motivation control the decision to continue or change behavior is not understood. Using a single fly treadmill, we show that hungry flies persistently track a food odor and increase their effort over repeated trials in the absence of reward suggesting that need dominates negative experience. We further show that odor tracking is regulated by two mushroom body output neurons (MBONs) connecting the MB to the lateral horn. These MBONs, together with dopaminergic neurons and Dop1R2 signaling, control behavioral persistence. Conversely, an octopaminergic neuron, VPM4, which directly innervates one of the MBONs, acts as a brake on odor tracking by connecting feeding and olfaction. Together, our data suggest a function for the MB in internal state-dependent expression of behavior that can be suppressed by external inputs conveying a competing behavioral drive. Hunger motivates persistent food odor tracking even without reward Two synaptically connected MBONs, -γ1pedc>αβ and -α2sc, regulate odor tracking Octopamine neurons connect feeding and counteract MBON and odor tracking Dopaminergic neurons and Dop1R2 signaling promote persistent tracking
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Affiliation(s)
- Sercan Sayin
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | | | - K P Siju
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Marina E Wosniack
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; Max Planck Institute for Brain Research, Computation in Neural Circuits Group, 60438 Frankfurt, Germany
| | - Laurence P Lewis
- Max Planck Institute of Neurobiology, Chemosensory Coding Group, 82152 Martinsried, Germany
| | - Lisa-Marie Frisch
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Benedikt Gansen
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Amelia Edmondson-Stait
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | | | | | | | | | - Davi D Bock
- HHMI Janelia Research Campus, Ashburn, VA 20147, USA
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Gregory S X E Jefferis
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK; Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Julijana Gjorgjieva
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; Max Planck Institute for Brain Research, Computation in Neural Circuits Group, 60438 Frankfurt, Germany
| | - Ilona C Grunwald Kadow
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; ZIEL - Institute for food and health, 85354 Freising, Germany; Max Planck Institute of Neurobiology, Chemosensory Coding Group, 82152 Martinsried, Germany.
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126
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Callahan RA, Roberts R, Sengupta M, Kimura Y, Higashijima SI, Bagnall MW. Spinal V2b neurons reveal a role for ipsilateral inhibition in speed control. eLife 2019; 8:e47837. [PMID: 31355747 PMCID: PMC6701946 DOI: 10.7554/elife.47837] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 07/26/2019] [Indexed: 12/22/2022] Open
Abstract
The spinal cord contains a diverse array of interneurons that govern motor output. Traditionally, models of spinal circuits have emphasized the role of inhibition in enforcing reciprocal alternation between left and right sides or flexors and extensors. However, recent work has shown that inhibition also increases coincident with excitation during contraction. Here, using larval zebrafish, we investigate the V2b (Gata3+) class of neurons, which contribute to flexor-extensor alternation but are otherwise poorly understood. Using newly generated transgenic lines we define two stable subclasses with distinct neurotransmitter and morphological properties. These V2b subclasses synapse directly onto motor neurons with differential targeting to speed-specific circuits. In vivo, optogenetic manipulation of V2b activity modulates locomotor frequency: suppressing V2b neurons elicits faster locomotion, whereas activating V2b neurons slows locomotion. We conclude that V2b neurons serve as a brake on axial motor circuits. Together, these results indicate a role for ipsilateral inhibition in speed control.
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Affiliation(s)
- Rebecca A Callahan
- Department of NeuroscienceWashington University School of MedicineSt LouisUnited States
| | - Richard Roberts
- Department of NeuroscienceWashington University School of MedicineSt LouisUnited States
| | - Mohini Sengupta
- Department of NeuroscienceWashington University School of MedicineSt LouisUnited States
| | | | | | - Martha W Bagnall
- Department of NeuroscienceWashington University School of MedicineSt LouisUnited States
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127
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Hashiguchi S, Doi H, Kunii M, Nakamura Y, Shimuta M, Suzuki E, Koyano S, Okubo M, Kishida H, Shiina M, Ogata K, Hirashima F, Inoue Y, Kubota S, Hayashi N, Nakamura H, Takahashi K, Katsumoto A, Tada M, Tanaka K, Sasaoka T, Miyatake S, Miyake N, Saitsu H, Sato N, Ozaki K, Ohta K, Yokota T, Mizusawa H, Mitsui J, Ishiura H, Yoshimura J, Morishita S, Tsuji S, Takeuchi H, Ishikawa K, Matsumoto N, Ishikawa T, Tanaka F. Ataxic phenotype with altered Ca V3.1 channel property in a mouse model for spinocerebellar ataxia 42. Neurobiol Dis 2019; 130:104516. [PMID: 31229688 DOI: 10.1016/j.nbd.2019.104516] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/06/2019] [Accepted: 06/19/2019] [Indexed: 11/16/2022] Open
Abstract
Spinocerebellar ataxia 42 (SCA42) is a neurodegenerative disorder recently shown to be caused by c.5144G > A (p.Arg1715His) mutation in CACNA1G, which encodes the T-type voltage-gated calcium channel CaV3.1. Here, we describe a large Japanese family with SCA42. Postmortem pathological examination revealed severe cerebellar degeneration with prominent Purkinje cell loss without ubiquitin accumulation in an SCA42 patient. To determine whether this mutation causes ataxic symptoms and neurodegeneration, we generated knock-in mice harboring c.5168G > A (p.Arg1723His) mutation in Cacna1g, corresponding to the mutation identified in the SCA42 family. Both heterozygous and homozygous mutants developed an ataxic phenotype from the age of 11-20 weeks and showed Purkinje cell loss at 50 weeks old. Degenerative change of Purkinje cells and atrophic thinning of the molecular layer were conspicuous in homozygous knock-in mice. Electrophysiological analysis of Purkinje cells using acute cerebellar slices from young mice showed that the point mutation altered the voltage dependence of CaV3.1 channel activation and reduced the rebound action potentials after hyperpolarization, although it did not significantly affect the basic properties of synaptic transmission onto Purkinje cells. Finally, we revealed that the resonance of membrane potential of neurons in the inferior olivary nucleus was decreased in knock-in mice, which indicates that p.Arg1723His CaV3.1 mutation affects climbing fiber signaling to Purkinje cells. Altogether, our study shows not only that a point mutation in CACNA1G causes an ataxic phenotype and Purkinje cell degeneration in a mouse model, but also that the electrophysiological abnormalities at an early stage of SCA42 precede Purkinje cell loss.
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Affiliation(s)
- Shunta Hashiguchi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Misako Kunii
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Yukihiro Nakamura
- Department of Pharmacology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Misa Shimuta
- Department of Pharmacology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Etsuko Suzuki
- Department of Pharmacology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Shigeru Koyano
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Masaki Okubo
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Hitaru Kishida
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Masaaki Shiina
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Fumiko Hirashima
- Department of Rehabilitation Medicine, Flower and Forest Tokyo Hospital, 2-3-6 Nishigahara, Kita-ku, Tokyo 114-0024, Japan
| | - Yukichi Inoue
- Department of Neurology, Toyama Prefectural Rehabilitation Hospital and Support Center for Children with Disabilities, 36 Shimoiino, Toyama 931-8517, Japan
| | - Shun Kubota
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Noriko Hayashi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Haruko Nakamura
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Keita Takahashi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Atsuko Katsumoto
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Mikiko Tada
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Kenichi Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Toshikuni Sasaoka
- Department of Comparative and Experimental Medicine, Center for Bioresource-based Researches, Brain Research Institute, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata 951-8585, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Nozomu Sato
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Kokoro Ozaki
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Kiyobumi Ohta
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Takanori Yokota
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Hidehiro Mizusawa
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Jun Mitsui
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Jun Yoshimura
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Shinichi Morishita
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Hideyuki Takeuchi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Kinya Ishikawa
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Taro Ishikawa
- Department of Pharmacology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
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128
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Deletion of Class II ADP-Ribosylation Factors in Mice Causes Tremor by the Nav1.6 Loss in Cerebellar Purkinje Cell Axon Initial Segments. J Neurosci 2019; 39:6339-6353. [PMID: 31201232 DOI: 10.1523/jneurosci.2002-18.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 05/14/2019] [Accepted: 05/31/2019] [Indexed: 12/29/2022] Open
Abstract
ADP-ribosylation factors (ARFs) are a family of small monomeric GTPases comprising six members categorized into three classes: class I (ARF1, 2, and 3), class II (ARF4 and 5), and class III (ARF6). In contrast to class I and III ARFs, which are the key regulators in vesicular membrane trafficking, the cellular function of class II ARFs remains unclear. In the present study, we generated class II ARF-deficient mice and found that ARF4+/-/ARF5-/- mice exhibited essential tremor (ET)-like behaviors. In vivo electrophysiological recordings revealed that ARF4+/-/ARF5-/- mice of both sexes exhibited abnormal brain activity when moving, raising the possibility of abnormal cerebellar excitability. Slice patch-clamp experiments demonstrated the reduced excitability of the cerebellar Purkinje cells (PCs) in ARF4+/-/ARF5-/- mice. Immunohistochemical and electrophysiological analyses revealed a severe and selective decrease of pore-forming voltage-dependent Na+ channel subunit Nav1.6, important for maintaining repetitive action potential firing, in the axon initial segment (AIS) of PCs. Importantly, this decrease in Nav1.6 protein localized in the AIS and the consequent tremors in ARF4+/-/ARF5-/- mice could be alleviated by the PC-specific expression of ARF5 using adeno-associated virus vectors. Together, our data demonstrate that the decreased expression of the class II ARF proteins in ARF4+/-/ARF5-/- mice, leading to a haploinsufficiency of ARF4 in the absence of ARF5, impairs the localization of Nav1.6 to the AIS and hence reduces the membrane excitability in PCs, resulting in the ET-like movement disorder. We suggest that class II ARFs function in localizing specific proteins, such as Nav1.6, to the AIS.SIGNIFICANCE STATEMENT We found that decreasing the expression of class II ARF proteins, through the generation of ARF4+/-/ARF5-/- mice, impairs Nav1.6 distribution to the axon initial segment (AIS) of cerebellar Purkinje cells (PCs), thereby resulting in the impairment of action potential firing of PCs. The ARF4+/-/ARF5-/- mutant mice exhibited movement-associated essential tremor (ET)-like behavior with pharmacological profiles similar to those in ET patients. The exogenous expression of ARF5 reduced the tremor phenotype and restored the localization of Nav1.6 immunoreactivity to the AIS in ARF4+/-/ARF5-/- mice. Thus, our results suggest that class II ARFs are involved in the localization of Nav1.6 to the AISs in cerebellar PCs and that the reduction of class II ARF activity leads to ET-like movement disorder.
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129
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Frechter S, Bates AS, Tootoonian S, Dolan MJ, Manton J, Jamasb AR, Kohl J, Bock D, Jefferis G. Functional and anatomical specificity in a higher olfactory centre. eLife 2019; 8:44590. [PMID: 31112127 PMCID: PMC6550879 DOI: 10.7554/elife.44590] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/12/2019] [Indexed: 12/16/2022] Open
Abstract
Most sensory systems are organized into parallel neuronal pathways that process distinct aspects of incoming stimuli. In the insect olfactory system, second order projection neurons target both the mushroom body, required for learning, and the lateral horn (LH), proposed to mediate innate olfactory behavior. Mushroom body neurons form a sparse olfactory population code, which is not stereotyped across animals. In contrast, odor coding in the LH remains poorly understood. We combine genetic driver lines, anatomical and functional criteria to show that the Drosophila LH has ~1400 neurons and >165 cell types. Genetically labeled LHNs have stereotyped odor responses across animals and on average respond to three times more odors than single projection neurons. LHNs are better odor categorizers than projection neurons, likely due to stereotyped pooling of related inputs. Our results reveal some of the principles by which a higher processing area can extract innate behavioral significance from sensory stimuli.
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Affiliation(s)
- Shahar Frechter
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Sina Tootoonian
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Neurophysiology of Behaviour Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Michael-John Dolan
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Janelia Research Campus, Howard Hughes Medical Institute, Chevy Chase, United States
| | - James Manton
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Johannes Kohl
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Davi Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Chevy Chase, United States
| | - Gregory Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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130
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Yang Y, Kreko-Pierce T, Howell R, Pugh JR. Long-term depression of presynaptic cannabinoid receptor function at parallel fibre synapses. J Physiol 2019; 597:3167-3181. [PMID: 31020998 DOI: 10.1113/jp277727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 04/18/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Inhibition of synaptic responses by activation of presynaptic cannabinoid type-1 (Cb1) receptors is reduced at parallel fibre synapses in the cerebellum following 4 Hz stimulation. Activation of adenylyl cyclase is necessary and sufficient for down-regulation of Cb1 receptors induced by 4 Hz stimulation. 4 Hz stimulation reduces Cb1 receptor function by (i) increasing the rate of endocannabinoid clearance from the synapse and (ii) decreasing expression of Cb1 receptors. ABSTRACT Cannabinoid type-1 receptors (Cb1R) are expressed in the presynaptic membrane of many synapses, including parallel fibre-Purkinje cell synapses in the cerebellum, where they are involved in short- and long-term plasticity of synaptic responses. We show that Cb1R expression itself is a plastic property of the synapse regulated by physiological activity patterns. We made patch clamp recordings from Purkinje cells in cerebellar slices and assessed Cb1R activity by measuring depolarization-induced suppression of excitation (DSE). We find that DSE is normally stable at parallel fibre synapses but, following 4 Hz stimulation, DSE is persistently reduced and recovers more rapidly. Using a combination of electrophysiology, pharmacology and biochemistry, we show that changes in DSE are a result of the reduced expression of Cb1Rs and increased degradation of endocannabinoids by monoacylglycerol lipase. Long-term changes in presynaptic Cb1R expression may alter other forms of Cb1R-dependent plasticity at parallel fibre synapses, priming or inhibiting the circuit for associative learning.
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Affiliation(s)
- Ying Yang
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Xiangya School of Medicine, Department of Pain, The Third Xiangya Hospital and Institute of Pain Medicine, Central South University, Changsha, Hunan Province, China
| | - Tabita Kreko-Pierce
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA
| | - Rebecca Howell
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Present address: Oklahoma Medical Research Foundation & University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Jason R Pugh
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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131
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Favorov OV, Pellicer-Morata V, DeJongh Curry AL, Ramshur JT, Brna A, Challener TD, Waters RS. A newly identified nociresponsive region in the transitional zone (TZ) in rat sensorimotor cortex. Brain Res 2019; 1717:228-234. [PMID: 31028729 DOI: 10.1016/j.brainres.2019.04.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/28/2019] [Accepted: 04/23/2019] [Indexed: 12/27/2022]
Abstract
The primary somatosensory cortex (S1) comprises a number of functionally distinct regions, reflecting the diversity of somatosensory receptor submodalities innervating the body. In particular, two spatially and functionally distinct nociceptive regions have been described in primate S1 (Vierck et al., 2013; Whitsel et al., 2019). One region is located mostly in Brodmann cytoarchitectonic area 1, where a subset of neurons exhibit functional characteristics associated with myelinated Aδ nociceptors and perception of 1st/sharp, discriminative pain. The second region is located at the transition between S1 and primary motor cortex (M1) in area 3a, where neurons exhibit functional characteristics associated with unmyelinated C nociceptors and perception of 2nd/slow, burning pain. To test the hypothesis that in rats the transitional zone (TZ) - which is a dysgranular region at the transition between M1 and S1 - is the functional equivalent of the nociresponsive region of area 3a in primates, extracellular spike discharge activity was recorded from TZ neurons in rats under general isoflurane anesthesia. Thermonoxious stimuli were applied by lowering the contralateral forepaw or hindpaw into a 48-51 °C heated water bath for 5-10 s. Neurons in TZ were found to be minimally affected by non-noxious somatosensory stimuli, but highly responsive to thermonoxious skin stimuli in a slow temporal summation manner closely resembling that of nociresponsive neurons in primate area 3a. Selective inactivation of TZ by topical lidocaine application suppressed or delayed the nociceptive withdrawal reflex, suggesting that TZ exerts a tonic facilitatory influence over spinal cord neurons producing this reflex. In conclusion, TZ appears to be a rat homolog of the nociresponsive part of monkey area 3a. A possibility is considered that this region might be primarily engaged in autonomic aspects of nociception.
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Affiliation(s)
- Oleg V Favorov
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Violeta Pellicer-Morata
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Amy L DeJongh Curry
- Department of Biomedical Engineering, University of Memphis, Memphis, TN 38152, USA
| | - John T Ramshur
- Department of Biomedical Engineering, University of Memphis, Memphis, TN 38152, USA
| | - Andrew Brna
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Timothy D Challener
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Robert S Waters
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Biomedical Engineering, University of Memphis, Memphis, TN 38152, USA.
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132
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Wester JC, Mahadevan V, Rhodes CT, Calvigioni D, Venkatesh S, Maric D, Hunt S, Yuan X, Zhang Y, Petros TJ, McBain CJ. Neocortical Projection Neurons Instruct Inhibitory Interneuron Circuit Development in a Lineage-Dependent Manner. Neuron 2019; 102:960-975.e6. [PMID: 31027966 DOI: 10.1016/j.neuron.2019.03.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 02/13/2019] [Accepted: 03/25/2019] [Indexed: 12/30/2022]
Abstract
Neocortical circuits consist of stereotypical motifs that must self-assemble during development. Recent evidence suggests that the subtype identity of both excitatory projection neurons (PNs) and inhibitory interneurons (INs) is important for this process. We knocked out the transcription factor Satb2 in PNs to induce those of the intratelencephalic (IT) type to adopt a pyramidal tract (PT)-type identity. Loss of IT-type PNs selectively disrupted the lamination and circuit integration of INs derived from the caudal ganglionic eminence (CGE). Strikingly, reprogrammed PNs demonstrated reduced synaptic targeting of CGE-derived INs relative to controls. In control mice, IT-type PNs targeted neighboring CGE INs, while PT-type PNs did not in deep layers, confirming this lineage-dependent motif. Finally, single-cell RNA sequencing revealed that major CGE IN subtypes were conserved after loss of IT PNs, but with differential transcription of synaptic proteins and signaling molecules. Thus, IT-type PNs influence CGE-derived INs in a non-cell-autonomous manner during cortical development.
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Affiliation(s)
- Jason C Wester
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Vivek Mahadevan
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Christopher T Rhodes
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Daniela Calvigioni
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA; Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Sanan Venkatesh
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Dragan Maric
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Steven Hunt
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Xiaoqing Yuan
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Yajun Zhang
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Timothy J Petros
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Chris J McBain
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
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133
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Khatri SN, Wu WC, Yang Y, Pugh JR. Direction of action of presynaptic GABA A receptors is highly dependent on the level of receptor activation. J Neurophysiol 2019; 121:1896-1905. [PMID: 30892973 DOI: 10.1152/jn.00779.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Many synapses, including parallel fiber synapses in the cerebellum, express presynaptic GABAA receptors. However, reports of the functional consequences of presynaptic GABAA receptor activation are variable across synapses, from inhibition to enhancement of transmitter release. We find that presynaptic GABAA receptor function is bidirectional at parallel fiber synapses depending on GABA concentration and modulation of GABAA receptors in mice. Activation of GABAA receptors by low GABA concentrations enhances glutamate release, whereas activation of receptors by higher GABA concentrations inhibits release. Furthermore, blocking GABAB receptors reduces GABAA receptor currents and shifts presynaptic responses toward greater enhancement of release across a wide range of GABA concentrations. Conversely, enhancing GABAA receptor currents with ethanol or neurosteroids shifts responses toward greater inhibition of release. The ability of presynaptic GABAA receptors to enhance or inhibit transmitter release at the same synapse depending on activity level provides a new mechanism for fine control of synaptic transmission by GABA and may explain conflicting reports of presynaptic GABAA receptor function across synapses. NEW & NOTEWORTHY GABAA receptors are widely expressed at presynaptic terminals in the central nervous system. However, previous reports have produced conflicting results on the function of these receptors at different synapses. We show that presynaptic GABAA receptor function is strongly dependent on the level of receptor activation. Low levels of receptor activation enhance transmitter release, whereas higher levels of activation inhibit release at the same synapses. This provides a novel mechanism by which presynaptic GABAA receptors fine-tune synaptic transmission.
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Affiliation(s)
- Shailesh N Khatri
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Wan-Chen Wu
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Ying Yang
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,Xiangya School of Medicine, Central South University , Changsha, Hunan , China
| | - Jason R Pugh
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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Begemann A, Acuña MA, Zweier M, Vincent M, Steindl K, Bachmann-Gagescu R, Hackenberg A, Abela L, Plecko B, Kroell-Seger J, Baumer A, Yamakawa K, Inoue Y, Asadollahi R, Sticht H, Zeilhofer HU, Rauch A. Further corroboration of distinct functional features in SCN2A variants causing intellectual disability or epileptic phenotypes. Mol Med 2019; 25:6. [PMID: 30813884 PMCID: PMC6391808 DOI: 10.1186/s10020-019-0073-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/05/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Deleterious variants in the voltage-gated sodium channel type 2 (Nav1.2) lead to a broad spectrum of phenotypes ranging from benign familial neonatal-infantile epilepsy (BFNIE), severe developmental and epileptic encephalopathy (DEE) and intellectual disability (ID) to autism spectrum disorders (ASD). Yet, the underlying mechanisms are still incompletely understood. METHODS To further elucidate the genotype-phenotype correlation of SCN2A variants we investigated the functional effects of six variants representing the phenotypic spectrum by whole-cell patch-clamp studies in transfected HEK293T cells and in-silico structural modeling. RESULTS The two variants p.L1342P and p.E1803G detected in patients with early onset epileptic encephalopathy (EE) showed profound and complex changes in channel gating, whereas the BFNIE variant p.L1563V exhibited only a small gain of channel function. The three variants identified in ID patients without seizures, p.R937C, p.L611Vfs*35 and p.W1716*, did not produce measurable currents. Homology modeling of the missense variants predicted structural impairments consistent with the electrophysiological findings. CONCLUSIONS Our findings support the hypothesis that complete loss-of-function variants lead to ID without seizures, small gain-of-function variants cause BFNIE and EE variants exhibit variable but profound Nav1.2 gating changes. Moreover, structural modeling was able to predict the severity of the variant impact, supporting a potential role of structural modeling as a prognostic tool. Our study on the functional consequences of SCN2A variants causing the distinct phenotypes of EE, BFNIE and ID contributes to the elucidation of mechanisms underlying the broad phenotypic variability reported for SCN2A variants.
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Affiliation(s)
- Anaïs Begemann
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Mario A Acuña
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland
| | - Markus Zweier
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Marie Vincent
- Service de génétique médicale, CHU Nantes, 44093, Nantes, France
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | | | - Annette Hackenberg
- Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland
| | - Lucia Abela
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland
| | - Barbara Plecko
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland.,Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, 8036, Graz, Austria
| | - Judith Kroell-Seger
- Children's department, Swiss Epilepsy Centre, Clinic Lengg, 8008, Zurich, Switzerland
| | - Alessandra Baumer
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako-shi, Saitama, 351-0198, Japan
| | - Yushi Inoue
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Heinrich Sticht
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Hanns Ulrich Zeilhofer
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland.,Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zürich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland. .,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland. .,Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology, University of Zurich, 8057, Zurich, Switzerland.
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135
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Singh M, Denny H, Smith C, Granados J, Renden R. Presynaptic loss of dynamin-related protein 1 impairs synaptic vesicle release and recycling at the mouse calyx of Held. J Physiol 2018; 596:6263-6287. [PMID: 30285293 DOI: 10.1113/jp276424] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/24/2018] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS This study characterizes the mechanisms underlying defects in synaptic transmission when dynamin-related protein 1 (DRP1) is genetically eliminated. Viral-mediated knockout of DRP1 from the presynaptic terminal at the mouse calyx of Held increased initial release probability, reduced the size of the synaptic vesicle recycling pool and impaired synaptic vesicle recycling. Transmission defects could be partially restored by increasing the intracellular calcium buffering capacity with EGTA-AM, implying close coupling of Ca2+ channels to synaptic vesicles was compromised. Acute restoration of ATP to physiological levels in the presynaptic terminal did not reverse the synaptic defects. Loss of DRP1 impairs mitochondrial morphology in the presynaptic terminal, which in turn seems to arrest synaptic maturation. ABSTRACT Impaired mitochondrial biogenesis and function is implicated in many neurodegenerative diseases, and likely affects synaptic neurotransmission prior to cellular loss. Dynamin-related protein 1 (DRP1) is essential for mitochondrial fission and is disrupted in neurodegenerative disease. In this study, we used the mouse calyx of Held synapse as a model to investigate the impact of presynaptic DRP1 loss on synaptic vesicle (SV) recycling and sustained neurotransmission. In vivo viral expression of Cre recombinase in ventral cochlear neurons of floxed-DRP1 mice generated a presynaptic-specific DRP1 knockout (DRP1-preKO), where the innervated postsynaptic cell was unperturbed. Confocal reconstruction of the calyx terminal suggested SV clusters and mitochondrial content were disrupted, and presynaptic terminal volume was decreased. Using postsynaptic voltage-clamp recordings, we found that DRP1-preKO synapses had larger evoked responses at low frequency stimulation. DRP1-preKO synapses also had profoundly altered short-term plasticity, due to defects in SV recycling. Readily releasable pool size, estimated with high-frequency trains, was dramatically reduced in DRP1-preKO synapses, suggesting an important role for DRP1 in maintenance of release-competent SVs at the presynaptic terminal. Presynaptic Ca2+ accumulation in the terminal was also enhanced in DRP1-preKO synapses. Synaptic transmission defects could be partially rescued with EGTA-AM, indicating close coupling of Ca2+ channels to SV distance normally found in mature terminals may be compromised by DRP1-preKO. Using paired recordings of the presynaptic and postsynaptic compartments, recycling defects could not be reversed by acute dialysis of ATP into the calyx terminals. Taken together, our results implicate a requirement for mitochondrial fission to coordinate postnatal synapse maturation.
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Affiliation(s)
- Mahendra Singh
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Henry Denny
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Christina Smith
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Jorge Granados
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Robert Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
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136
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Liang SL. The glutamine-glutamate cycle regulates synaptic glutamate release in the ventrolateral ventromedial nucleus of the hypothalamus of perinatal female rats. J Neuroendocrinol 2018; 30:e12642. [PMID: 30168642 DOI: 10.1111/jne.12642] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/23/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022]
Abstract
The astrocytic glutamine (Gln)-glutamate (Glu) cycle (GGC) supplies Gln for the regulation of glutamatergic synaptic transmission (GST) in the adult hippocampus. Increased synaptic Glu release in the perinatal ventrolateral ventromedial nucleus of the hypothalamus (vlVMH) modulates sexual differentiation, however, whether GGC regulates GST in the perinatal vlVMH has not been determined. Sex differences in oestradiol (E2 ) levels exist in the neonatal hypothalamus, and E2 increases levels of glutamine synthetase and glutaminase, two key enzymes involved in the GGC. Thus, it is hypothesised that sexually dimorphic phenotypes may exist in glutamatergic synapses associated with the GGC in the vlVMH in perinatal rats. Whole-cell voltage-clamp recordings in vlVMH neurones in brain slices from male and female pups revealed that pharmacological disruption of the GGC by α-(methylamino) isobutyric acid (5 mmol L-1 ), which blocks neuronal Gln uptake; or by l-methionine sulphoximine (1.5 mmol L-1 ), which inhibits astrocytic Gln synthesis, decreased miniature excitatory postsynaptic current (mEPSC) amplitudes in female but not male pups. By contrast, GGC interruptions decreased evoked (e)EPSC amplitudes in both sexes following increased synaptic activity produced by a period of stimulation. In male pups, the decreased eEPSCs were attributable to reduced Glu release, as assessed by paired-pulse stimulations, whereas, in female pups, they were attributable to decreased Glu content in the synaptic vesicles, as measured by strontium-evoked mEPSCs. The l-methionine sulphoximine-mediated decrease in eEPSCs was rapidly rescued by exogenous Gln in female but not male pups. The reductions in mEPSCs and eEPSCs in female pups were accompanied by enhanced blocking effects of the low-affinity Glu AMPA receptor antagonist, γ-d-glutamylglycine, consistent with diminished Glu release. In conclusion, female, but not male pups, rely on constitutive astrocytic Gln for sustained synaptic Glu release in the vlVMH. This glutamatergic synaptic phenotype may be associated with brain and behaviour feminisation and/or defeminisation in rats.
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Affiliation(s)
- Shu-Ling Liang
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Linkou, Tao-Yuan, Taiwan
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Tao-Yuan, Taiwan
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137
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Kalmbach BE, Buchin A, Long B, Close J, Nandi A, Miller JA, Bakken TE, Hodge RD, Chong P, de Frates R, Dai K, Maltzer Z, Nicovich PR, Keene CD, Silbergeld DL, Gwinn RP, Cobbs C, Ko AL, Ojemann JG, Koch C, Anastassiou CA, Lein ES, Ting JT. h-Channels Contribute to Divergent Intrinsic Membrane Properties of Supragranular Pyramidal Neurons in Human versus Mouse Cerebral Cortex. Neuron 2018; 100:1194-1208.e5. [PMID: 30392798 DOI: 10.1016/j.neuron.2018.10.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/05/2018] [Accepted: 10/05/2018] [Indexed: 12/18/2022]
Abstract
Gene expression studies suggest that differential ion channel expression contributes to differences in rodent versus human neuronal physiology. We tested whether h-channels more prominently contribute to the physiological properties of human compared to mouse supragranular pyramidal neurons. Single-cell/nucleus RNA sequencing revealed ubiquitous HCN1-subunit expression in excitatory neurons in human, but not mouse, supragranular layers. Using patch-clamp recordings, we found stronger h-channel-related membrane properties in supragranular pyramidal neurons in human temporal cortex, compared to mouse supragranular pyramidal neurons in temporal association area. The magnitude of these differences depended upon cortical depth and was largest in pyramidal neurons in deep L3. Additionally, pharmacologically blocking h-channels produced a larger change in membrane properties in human compared to mouse neurons. Finally, using biophysical modeling, we provide evidence that h-channels promote the transfer of theta frequencies from dendrite-to-soma in human L3 pyramidal neurons. Thus, h-channels contribute to between-species differences in a fundamental neuronal property.
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Affiliation(s)
- Brian E Kalmbach
- Allen Institute for Brain Science, Seattle, WA 98109, USA; Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
| | - Anatoly Buchin
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Brian Long
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Jennie Close
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Anirban Nandi
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | | | - Peter Chong
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Kael Dai
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Zoe Maltzer
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - C Dirk Keene
- Department of Pathology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Daniel L Silbergeld
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Ryder P Gwinn
- Epilepsy Surgery and Functional Neurosurgery, Swedish Neuroscience Institute, Seattle, WA 98122, USA
| | - Charles Cobbs
- The Ben and Catherine Ivy Center for Advanced Brain Tumor Treatment, Swedish Neuroscience Institute, Seattle, WA 98122, USA
| | - Andrew L Ko
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA 98195, USA; Regional Epilepsy Center at Harborview Medical Center, Seattle, WA 98104, USA
| | - Jeffrey G Ojemann
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA 98195, USA; Regional Epilepsy Center at Harborview Medical Center, Seattle, WA 98104, USA
| | - Christof Koch
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Costas A Anastassiou
- Allen Institute for Brain Science, Seattle, WA 98109, USA; Department of Neurology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ed S Lein
- Allen Institute for Brain Science, Seattle, WA 98109, USA; Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA 98195, USA
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138
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Canals I, Ginisty A, Quist E, Timmerman R, Fritze J, Miskinyte G, Monni E, Hansen MG, Hidalgo I, Bryder D, Bengzon J, Ahlenius H. Rapid and efficient induction of functional astrocytes from human pluripotent stem cells. Nat Methods 2018; 15:693-696. [PMID: 30127505 DOI: 10.1038/s41592-018-0103-2] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 07/09/2018] [Indexed: 11/09/2022]
Abstract
The derivation of astrocytes from human pluripotent stem cells is currently slow and inefficient. We demonstrate that overexpression of the transcription factors SOX9 and NFIB in human pluripotent stem cells rapidly and efficiently yields homogeneous populations of induced astrocytes. In our study these cells exhibited molecular and functional properties resembling those of adult human astrocytes and were deemed suitable for disease modeling. Our method provides new possibilities for the study of human astrocytes in health and disease.
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Affiliation(s)
- Isaac Canals
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden.,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden
| | - Aurélie Ginisty
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden.,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden
| | - Ella Quist
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden.,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden
| | - Raissa Timmerman
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden.,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden
| | - Jonas Fritze
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden.,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden
| | - Giedre Miskinyte
- Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden.,Laboratory of Stem Cells and Restorative Neurology, Lund University and Skåne University Hospital, Lund, Sweden
| | - Emanuela Monni
- Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund, Sweden.,Laboratory of Stem Cells and Restorative Neurology, Lund University and Skåne University Hospital, Lund, Sweden
| | | | - Isabel Hidalgo
- Lund Stem Cell Center, Lund, Sweden.,Institution for Laboratory Medicine, Division of Molecular Hematology, Faculty of Medicine, Lund University, Lund, Sweden
| | - David Bryder
- Lund Stem Cell Center, Lund, Sweden.,Institution for Laboratory Medicine, Division of Molecular Hematology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Johan Bengzon
- Lund Stem Cell Center, Lund, Sweden.,Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund, Sweden
| | - Henrik Ahlenius
- Stem Cells, Aging and Neurodegeneration Group, Faculty of Medicine, Lund University, Lund, Sweden. .,Division of Neurology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden. .,Lund Stem Cell Center, Lund, Sweden.
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139
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Ritzau-Jost A, Jablonski L, Viotti J, Lipstein N, Eilers J, Hallermann S. Apparent calcium dependence of vesicle recruitment. J Physiol 2018; 596:4693-4707. [PMID: 29928766 DOI: 10.1113/jp275911] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/11/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Synaptic transmission relies on the recruitment of neurotransmitter-filled vesicles to presynaptic release sites. Increased intracellular calcium buffering slows the recovery from synaptic depression, suggesting that vesicle recruitment is a calcium-dependent process. However, the molecular mechanisms of vesicle recruitment have only been investigated at some synapses. We investigate the role of calcium in vesicle recruitment at the cerebellar mossy fibre to granule cell synapse. We find that increased intracellular calcium buffering slows the recovery from depression following physiological stimulation. However, the recovery is largely resistant to perturbation of the molecular pathways previously shown to mediate calcium-dependent vesicle recruitment. Furthermore, we find two pools of vesicles with different recruitment speeds and show that models incorporating two pools of vesicles with different calcium-independent recruitment rates can explain our data. In this framework, increased calcium buffering prevents the release of intrinsically fast-recruited vesicles but does not change the vesicle recruitment rates themselves. ABSTRACT During sustained synaptic transmission, recruitment of new transmitter-filled vesicles to the release site counteracts vesicle depletion and thus synaptic depression. An elevated intracellular Ca2+ concentration has been proposed to accelerate the rate of vesicle recruitment at many synapses. This conclusion is often based on the finding that increased intracellular Ca2+ buffering slows the recovery from synaptic depression. However, the molecular mechanisms of the activity-dependent acceleration of vesicle recruitment have only been analysed at some synapses. Using physiological stimulation patterns in postsynaptic recordings and step depolarizations in presynaptic bouton recordings, we investigate vesicle recruitment at cerebellar mossy fibre boutons. We show that increased intracellular Ca2+ buffering slows recovery from depression dramatically. However, pharmacological and genetic interference with calmodulin or the calmodulin-Munc13 pathway, which has been proposed to mediate Ca2+ -dependence of vesicle recruitment, barely affects vesicle recovery from depression. Furthermore, we show that cerebellar mossy fibre boutons have two pools of vesicles: rapidly fusing vesicles that recover slowly and slowly fusing vesicles that recover rapidly. Finally, models adopting such two pools of vesicles with Ca2+ -independent recruitment rates can explain the slowed recovery from depression upon increased Ca2+ buffering. Our data do not rule out the involvement of the calmodulin-Munc13 pathway during stronger stimuli or other molecular pathways mediating Ca2+ -dependent vesicle recruitment at cerebellar mossy fibre boutons. However, we show that well-established two-pool models predict an apparent Ca2+ -dependence of vesicle recruitment. Thus, previous conclusions of Ca2+ -dependent vesicle recruitment based solely on increased intracellular Ca2+ buffering should be considered with caution.
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Affiliation(s)
- Andreas Ritzau-Jost
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Lukasz Jablonski
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Julio Viotti
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany.,Department of Anatomy and Embryology, Center of Anatomy, University Medical Center Göttingen, Göttingen, Germany
| | - Noa Lipstein
- Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jens Eilers
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Stefan Hallermann
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
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Mossy Cells Control Adult Neural Stem Cell Quiescence and Maintenance through a Dynamic Balance between Direct and Indirect Pathways. Neuron 2018; 99:493-510.e4. [PMID: 30057205 DOI: 10.1016/j.neuron.2018.07.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 05/16/2018] [Accepted: 07/05/2018] [Indexed: 11/23/2022]
Abstract
Mossy cells (MCs) represent a major population of excitatory neurons in the adult dentate gyrus, a brain region where new neurons are generated from radial neural stem cells (rNSCs) throughout life. Little is known about the role of MCs in regulating rNSCs. Here we demonstrate that MC commissural projections structurally and functionally interact with rNSCs through both the direct glutamatergic MC-rNSC pathway and the indirect GABAergic MC-local interneuron-rNSC pathway. Specifically, moderate MC activation increases rNSC quiescence through the dominant indirect pathway, while high MC activation increases rNSC activation through the dominant direct pathway. In contrast, MC inhibition or ablation leads to a transient increase of rNSC activation, but rNSC depletion only occurs after chronic ablation of MCs. Together, our study identifies MCs as a critical stem cell niche component that dynamically controls adult NSC quiescence and maintenance under various MC activity states through a balance of direct glutamatergic and indirect GABAergic signaling onto rNSCs.
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Robin LM, Oliveira da Cruz JF, Langlais VC, Martin-Fernandez M, Metna-Laurent M, Busquets-Garcia A, Bellocchio L, Soria-Gomez E, Papouin T, Varilh M, Sherwood MW, Belluomo I, Balcells G, Matias I, Bosier B, Drago F, Van Eeckhaut A, Smolders I, Georges F, Araque A, Panatier A, Oliet SHR, Marsicano G. Astroglial CB 1 Receptors Determine Synaptic D-Serine Availability to Enable Recognition Memory. Neuron 2018; 98:935-944.e5. [PMID: 29779943 DOI: 10.1016/j.neuron.2018.04.034] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 03/20/2018] [Accepted: 04/24/2018] [Indexed: 12/22/2022]
Abstract
Bidirectional communication between neurons and astrocytes shapes synaptic plasticity and behavior. D-serine is a necessary co-agonist of synaptic N-methyl-D-aspartate receptors (NMDARs), but the physiological factors regulating its impact on memory processes are scantly known. We show that astroglial CB1 receptors are key determinants of object recognition memory by determining the availability of D-serine at hippocampal synapses. Mutant mice lacking CB1 receptors from astroglial cells (GFAP-CB1-KO) displayed impaired object recognition memory and decreased in vivo and in vitro long-term potentiation (LTP) at CA3-CA1 hippocampal synapses. Activation of CB1 receptors increased intracellular astroglial Ca2+ levels and extracellular levels of D-serine in hippocampal slices. Accordingly, GFAP-CB1-KO displayed lower occupancy of the co-agonist binding site of synaptic hippocampal NMDARs. Finally, elevation of D-serine levels fully rescued LTP and memory impairments of GFAP-CB1-KO mice. These data reveal a novel mechanism of in vivo astroglial control of memory and synaptic plasticity via the D-serine-dependent control of NMDARs.
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Affiliation(s)
- Laurie M Robin
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - José F Oliveira da Cruz
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France; Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95123 Catania, Italy
| | - Valentin C Langlais
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | | | - Mathilde Metna-Laurent
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France; Aelis Farma, 33077 Bordeaux, France
| | - Arnau Busquets-Garcia
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Luigi Bellocchio
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Edgar Soria-Gomez
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France; Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thomas Papouin
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Marjorie Varilh
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Mark W Sherwood
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Ilaria Belluomo
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Georgina Balcells
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Isabelle Matias
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Barbara Bosier
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95123 Catania, Italy
| | - Ann Van Eeckhaut
- Vrije Universiteit Brussel, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research group Experimental Pharmacology, Center for Neurosciences (C4N), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Ilse Smolders
- Vrije Universiteit Brussel, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research group Experimental Pharmacology, Center for Neurosciences (C4N), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Francois Georges
- University of Bordeaux, 33077 Bordeaux, France; Centre National de la Recherche Scientifique, Neurodegenerative Diseases Institute, UMR 5293, 33076 Bordeaux, France
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Aude Panatier
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Stéphane H R Oliet
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France
| | - Giovanni Marsicano
- INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France; University of Bordeaux, 33077 Bordeaux, France.
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