1
|
Estrada-Sánchez AM, Castro D, Portillo-Ortiz K, Jang K, Nedjat-Haiem M, Levine MS, Cepeda C. Complete but not partial inhibition of glutamate transporters exacerbates cortical excitability in the R6/2 mouse model of Huntington's disease. CNS Neurosci Ther 2018; 25:509-518. [PMID: 30311425 DOI: 10.1111/cns.13070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 01/05/2023] Open
Abstract
AIM Deficient glutamate reuptake occurs in the cerebral cortex of Huntington's disease (HD) patients and murine models. Here, we examine the effects of partial or complete blockade of glutamate transporters on excitatory postsynaptic currents (EPSCs) of cortical pyramidal neurons (CPNs). METHODS Whole-cell patch clamp recordings of CPNs in slices from symptomatic R6/2 mice and wild-type (WT) littermates were used to examine the effects of selective or concurrent inhibition of glutamate reuptake transporters. RESULTS Selective inhibition of the glial glutamate transporter 1 (GLT-1) or the glutamate aspartate transporter (GLAST) produced slight decreases in decay time of evoked EPSCs in CPNs from WT and R6/2 mice with no significant differences between genotypes. In contrast, concurrent inhibition of both transporters with DL-TBOA induced a significant increase in area and decay time and this effect was significantly greater in R6/2 CPNs. Furthermore, full blockade also reduced spontaneous EPSC frequency and exacerbated epileptiform activity in CPNs from symptomatic R6/2 mice. CONCLUSIONS R6/2 CPNs are more sensitive to glutamate accumulation during full inhibition of both glutamate transporters, and these neurons have homeostatic mechanisms to cope with inhibition of GLT-1 or GLAST by a mechanism that involves upregulation of either transporter when the other is deficient.
Collapse
Affiliation(s)
- Ana María Estrada-Sánchez
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Daniel Castro
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Kenia Portillo-Ortiz
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Katrina Jang
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Michael Nedjat-Haiem
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| |
Collapse
|
2
|
De Backer JF, Monlezun S, Detraux B, Gazan A, Vanopdenbosch L, Cheron J, Cannazza G, Valverde S, Cantacorps L, Nassar M, Venance L, Valverde O, Faure P, Zoli M, De Backer O, Gall D, Schiffmann SN, de Kerchove d'Exaerde A. Deletion of Maged1 in mice abolishes locomotor and reinforcing effects of cocaine. EMBO Rep 2018; 19:embr.201745089. [PMID: 30002119 DOI: 10.15252/embr.201745089] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 12/21/2022] Open
Abstract
Melanoma antigen genes (Mage) were first described as tumour markers. However, some of Mage are also expressed in healthy cells where their functions remain poorly understood. Here, we describe an unexpected role for one of these genes, Maged1, in the control of behaviours related to drug addiction. Mice lacking Maged1 are insensitive to the behavioural effects of cocaine as assessed by locomotor sensitization, conditioned place preference (CPP) and drug self-administration. Electrophysiological experiments in brain slices and conditional knockout mice demonstrate that Maged1 is critical for cortico-accumbal neurotransmission. Further, expression of Maged1 in the prefrontal cortex (PFC) and the amygdala, but not in dopaminergic or striatal and other GABAergic neurons, is necessary for cocaine-mediated behavioural sensitization, and its expression in the PFC is also required for cocaine-induced extracellular dopamine (DA) release in the nucleus accumbens (NAc). This work identifies Maged1 as a critical molecule involved in cellular processes and behaviours related to addiction.
Collapse
Affiliation(s)
- Jean-François De Backer
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Stéphanie Monlezun
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Bérangère Detraux
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Adeline Gazan
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Laura Vanopdenbosch
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Julian Cheron
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Giuseppe Cannazza
- Dipartimento di Scienze della Vita, Centro di Neuroscienze e Neurotecnologie, Università degli Studi di Modena e Reggio Emilia, Modena, Italy
| | - Sébastien Valverde
- INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), UPMC Univ Paris 06 Sorbonne Universités, Paris, France
| | - Lídia Cantacorps
- Departament de Ciències Experimentals i de la Salut, Grup de Recerca en Neurobiologia del Comportament (GReNeC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Pompeu Fabra, Barcelone, Spain
| | - Mérie Nassar
- Center for Interdisciplinary Research in Biology, Collège de France, INSERM U1050, CNRS UMR7241, Labex Memolife, Paris, France
| | - Laurent Venance
- Center for Interdisciplinary Research in Biology, Collège de France, INSERM U1050, CNRS UMR7241, Labex Memolife, Paris, France
| | - Olga Valverde
- Departament de Ciències Experimentals i de la Salut, Grup de Recerca en Neurobiologia del Comportament (GReNeC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Pompeu Fabra, Barcelone, Spain
| | - Philippe Faure
- INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), UPMC Univ Paris 06 Sorbonne Universités, Paris, France
| | - Michele Zoli
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Centro di Neuroscienze e Neurotecnologie, Università degli Studi di Modena e Reggio Emilia, Modena, Italy
| | - Olivier De Backer
- URPHYM (Unité de Recherche en Physiologie Moléculaire), NARILIS (Namur Research Institute for Life Sciences), Université de Namur, Namur, Belgium
| | - David Gall
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Serge N Schiffmann
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alban de Kerchove d'Exaerde
- Laboratoire de Neurophysiologie, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium .,WELBIO, Brussels, Belgium
| |
Collapse
|
3
|
Jantrapirom S, Lo Piccolo L, Yoshida H, Yamaguchi M. Depletion of Ubiquilin induces an augmentation in soluble ubiquitinated Drosophila TDP-43 to drive neurotoxicity in the fly. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3038-3049. [PMID: 29936333 DOI: 10.1016/j.bbadis.2018.06.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/16/2018] [Accepted: 06/20/2018] [Indexed: 12/13/2022]
Abstract
The proteostasis machinery has critical functions in metabolically active cells such as neurons. Ubiquilins (UBQLNs) may decide the fate of proteins, with its ability to bind and deliver ubiquitinated misfolded or no longer functionally required proteins to the ubiquitin-proteasome system (UPS) and/or autophagy. Missense mutations in UBQLN2 have been linked to X-linked dominant amyotrophic lateral sclerosis with frontotemporal dementia (ALS-FTD). Although aggregation-prone TAR DNA-binding protein 43 (TDP-43) has been recognized as a major component of the ubiquitin pathology, the mechanisms by which UBQLN involves in TDP-43 proteinopathy have not yet been elucidated in detail. We previously characterized a new Drosophila Ubiquilin (dUbqn) knockdown model that produces learning/memory and locomotive deficits during the proteostasis impairment. In the present study, we demonstrated that the depletion of dUbqn markedly affected the expression and sub-cellular localization of Drosophila TDP-43 (TBPH), resulting in a cytoplasmic ubiquitin-positive (Ub+) TBPH pathology. Although we found that the knockdown of dUbqn widely altered and affected the turnover of a large number of proteins, we herein showed that an augmented soluble cytoplasmic Ub+-TBPH is as a crucial source of neurotoxicity following the depletion of dUbqn. We demonstrated that dUbqn knockdown-related neurotoxicity may be rescued by either restoring the proteostasis machinery or reducing the expression of TBPH. These novel results extend our knowledge on the UBQLN loss-of-function pathomechanism and may contribute to the identification of new therapeutics for ALS-FTD and aging-related diseases.
Collapse
Affiliation(s)
- Salinee Jantrapirom
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Luca Lo Piccolo
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; Department of Neurotherapeutics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| |
Collapse
|
4
|
Rebec GV. Corticostriatal network dysfunction in Huntington's disease: Deficits in neural processing, glutamate transport, and ascorbate release. CNS Neurosci Ther 2018; 24:281-291. [PMID: 29464896 PMCID: PMC6489880 DOI: 10.1111/cns.12828] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/10/2018] [Accepted: 01/27/2018] [Indexed: 12/25/2022] Open
Abstract
AIMS This review summarizes evidence for dysfunctional connectivity between cortical and striatal neurons in Huntington's disease (HD), a fatal neurodegenerative condition caused by a single gene mutation. The focus is on data derived from recording of electrophysiological signals in behaving transgenic mouse models. DISCUSSIONS Firing patterns of individual neurons and the frequency oscillations of local field potentials indicate a disruption in corticostriatal processing driven, in large part, by interactions between cells that contain the mutant gene rather than the mutant gene alone. Dysregulation of glutamate, an excitatory amino acid released by cortical afferents, plays a key role in the breakdown of corticostriatal communication, a process modulated by ascorbate, an antioxidant vitamin found in high concentration in striatum. Up-regulation of glutamate transport by drug administration or viral-vector delivery improves ascorbate homeostasis and neurobehavioral processing in HD mice. Further analysis of electrophysiological data, including the use of sophisticated computational strategies, is required to discern how behavioral demands modulate the flow of corticostriatal information and its disruption by HD. CONCLUSIONS Long before massive cell loss occurs, HD impairs the mechanisms by which cortical and striatal neurons communicate. A key problem identified in transgenic animal models is dysregulation of the dynamic changes in extracellular glutamate and ascorbate. Improved understanding of how these neurochemical systems impact corticostriatal communication is necessary before an effective therapeutic strategy can emerge.
Collapse
Affiliation(s)
- George V. Rebec
- Program in NeuroscienceDepartment of Psychological and Brain SciencesIndiana UniversityBloomingtonINUSA
| |
Collapse
|
5
|
Astrocytes and presynaptic plasticity in the striatum: Evidence and unanswered questions. Brain Res Bull 2018; 136:17-25. [DOI: 10.1016/j.brainresbull.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/30/2016] [Accepted: 01/02/2017] [Indexed: 02/03/2023]
|
6
|
Khakh BS, Beaumont V, Cachope R, Munoz-Sanjuan I, Goldman SA, Grantyn R. Unravelling and Exploiting Astrocyte Dysfunction in Huntington's Disease. Trends Neurosci 2017; 40:422-437. [PMID: 28578789 PMCID: PMC5706770 DOI: 10.1016/j.tins.2017.05.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/24/2017] [Accepted: 05/01/2017] [Indexed: 01/02/2023]
Abstract
Astrocytes are abundant within mature neural circuits and are involved in brain disorders. Here, we summarize our current understanding of astrocytes and Huntington's disease (HD), with a focus on correlative and causative dysfunctions of ion homeostasis, calcium signaling, and neurotransmitter clearance, as well as on the use of transplanted astrocytes to produce therapeutic benefit in mouse models of HD. Overall, the data suggest that astrocyte dysfunction is an important contributor to the onset and progression of some HD symptoms in mice. Additional exploration of astrocytes in HD mouse models and humans is needed and may provide new therapeutic opportunities to explore in conjunction with neuronal rescue and repair strategies.
Collapse
Affiliation(s)
- Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA; Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA.
| | - Vahri Beaumont
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, CA 90045, USA
| | - Roger Cachope
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, CA 90045, USA
| | | | - Steven A Goldman
- Center for Translational Neuromedicine, University of Rochester, Rochester, NY 14642, USA; Center for Neuroscience, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Rosemarie Grantyn
- Exzellenzcluster NeuroCure & Abt. Experimentelle Neurologie, Charité - Universitätsmedizin Berlin, Robert-Koch-Platz 4, D-10115 Berlin, Germany
| |
Collapse
|
7
|
Tiveron MC, Beurrier C, Céni C, Andriambao N, Combes A, Koehl M, Maurice N, Gatti E, Abrous DN, Kerkerian-Le Goff L, Pierre P, Cremer H. LAMP5 Fine-Tunes GABAergic Synaptic Transmission in Defined Circuits of the Mouse Brain. PLoS One 2016; 11:e0157052. [PMID: 27272053 PMCID: PMC4896627 DOI: 10.1371/journal.pone.0157052] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/24/2016] [Indexed: 11/19/2022] Open
Abstract
LAMP5 is member of the LAMP family of membrane proteins. In contrast to the canonical members of this protein family, LAMP1 and LAMP2, which show widespread expression in many tissues, LAMP 5 is brain specific in mice. In C. elegans, the LAMP5 ortholog UNC-46 has been suggested to act a trafficking chaperone, essential for the correct targeting of the nematode vesicular GABA-transporter UNC-47. We show here that in the mouse brain LAMP5 is expressed in subpopulations of GABAergic forebrain neurons in the striato-nigral system and the olfactory bulb. The protein was present at synaptic terminals, overlapping with the mammalian vesicular GABA-transporter VGAT. In LAMP5-deficient mice localization of the transporter was unaffected arguing against a conserved role in VGAT trafficking. Electrophysiological analyses in mutants showed alterations in short term synaptic plasticity suggesting that LAMP5 is involved in controlling the dynamics of evoked GABAergic transmission. At the behavioral level, LAMP5 mutant mice showed decreased anxiety and deficits in olfactory discrimination. Altogether, this work implicates LAMP5 function in GABAergic neurotransmission in defined neuronal subpopulations.
Collapse
Affiliation(s)
- Marie-Catherine Tiveron
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Corinne Beurrier
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Claire Céni
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Naly Andriambao
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Alexis Combes
- Centre d’Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm U1104, CNRS UMR7280, 13288, Marseille, France
| | - Muriel Koehl
- Neurogenesis and Physiopathology Group, INSERM U862, NeuroCentre Magendie, 33076, Bordeaux, France
| | - Nicolas Maurice
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Evelina Gatti
- Centre d’Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm U1104, CNRS UMR7280, 13288, Marseille, France
| | - Dhoher Nora Abrous
- Neurogenesis and Physiopathology Group, INSERM U862, NeuroCentre Magendie, 33076, Bordeaux, France
| | - Lydia Kerkerian-Le Goff
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| | - Philippe Pierre
- Centre d’Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm U1104, CNRS UMR7280, 13288, Marseille, France
| | - Harold Cremer
- Aix-Marseille University, Centre National pour la Recherche Scientifique, IBDM, Developmental Biology Institute of Marseille, UMR 7288, 13009, Marseille, France
| |
Collapse
|
8
|
Early exposure to dynamic environments alters patterns of motor exploration throughout the lifespan. Behav Brain Res 2016; 302:81-7. [PMID: 26778790 DOI: 10.1016/j.bbr.2016.01.007] [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: 07/20/2015] [Revised: 12/01/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022]
Abstract
We assessed early rearing conditions on aging-related changes in mouse behavior. Two isolated-housing groups, running wheel (IHRW) and empty cage (IHEC), were compared against two enriched environments, static (EEST) and dynamic (EEDY), both of which included toys and other mice. For EEDY, the location of toys and sources of food and water changed daily, but remained constant for EEST. All mice, randomly assigned to one of the four groups at ∼4 weeks of age, remained in their respective environments for 25 weeks followed by single housing in empty cages. Beginning at ∼40 weeks of age, all mice were tested at monthly intervals in a plus-shaped maze in which we measured the number of arm entries and the probability of entering a perpendicular arm. Despite making significantly more arm entries than any other group, IHEC mice also were less likely to turn into the left or right arm, a sign of motor inflexibility. Both EEDY and EEST mice showed enhanced turning relative to IHRW and IHEC groups, but only EEDY mice maintained their turning performance for up to ∼100 weeks of age. EEDY and EEST mice also were unique in showing an increase in expression of the major glutamate transporter (GLT1) in striatum, but a decrease in motor cortex, suggesting a need for further assessment of environmental manipulations on long-term changes in forebrain glutamate transmission. Our behavioral results indicate that early exposure to continually changing environments, rather than socialization or exercise alone, results in life-long changes in patterns of motor exploration.
Collapse
|
9
|
Cortical efferents lacking mutant huntingtin improve striatal neuronal activity and behavior in a conditional mouse model of Huntington's disease. J Neurosci 2015; 35:4440-51. [PMID: 25762686 DOI: 10.1523/jneurosci.2812-14.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Abnormal electrophysiological activity in the striatum, which receives dense innervation from the cerebral cortex, is believed to set the stage for the behavioral phenotype observed in Huntington's disease (HD), a neurodegenerative condition caused by mutation of the huntingtin (mhtt) protein. However, cortical involvement is far from clear. To determine whether abnormal striatal processing can be explained by mhtt alone (cell-autonomous model) or by mhtt in the corticostriatal projection cell-cell interaction model, we used BACHD/Emx1-Cre (BE) mice, a conditional HD model in which full-length mhtt is genetically reduced in cortical output neurons, including those that project to the striatum. Animals were assessed beginning at 20 weeks of age for at least the next 40 weeks, a range over which presymptomatic BACHD mice become symptomatic. Both open-field and nest-building behavior deteriorated progressively in BACHD mice relative to both BE and wild-type (WT) mice. Neuronal activity patterns in the dorsal striatum, which receives input from the primary motor cortex (M1), followed a similar age progression because BACHD activity changed more rapidly than either BE or WT mice. However, in the M1, BE neuronal activity differed significantly from both WT and BACHD. Although abnormal cortical activity in BE mice likely reflects input from mhtt-expressing afferents, including cortical interneurons, improvements in BE striatal activity and behavior suggest a critical role for mhtt in cortical output neurons in shaping the onset and progression of striatal dysfunction.
Collapse
|
10
|
Ugbode CI, Hirst WD, Rattray M. Neuronal influences are necessary to produce mitochondrial co-localization with glutamate transporters in astrocytes. J Neurochem 2014; 130:668-77. [PMID: 24814819 PMCID: PMC4283053 DOI: 10.1111/jnc.12759] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 05/01/2014] [Accepted: 05/05/2014] [Indexed: 12/28/2022]
Abstract
Recent evidence suggests that the predominant astrocyte glutamate transporter, GLT-1/ Excitatory Amino Acid Transporter 2 (EAAT2) is associated with mitochondria. We used primary cultures of mouse astrocytes to assess co-localization of GLT-1 with mitochondria, and tested whether the interaction was dependent on neurons, actin polymerization or the kinesin adaptor, TRAK2. Mouse primary astrocytes were transfected with constructs expressing V5-tagged GLT-1, pDsRed1-Mito with and without dominant negative TRAK2. Astrocytes were visualized using confocal microscopy and co-localization was quantified using Volocity software. Image analysis of confocal z-stacks revealed no co-localization between mitochondria and GLT-1 in pure astrocyte cultures. Co-culture of astrocytes with primary mouse cortical neurons revealed more mitochondria in processes and a positive correlation between mitochondria and GLT-1. This co-localization was not further enhanced after neuronal depolarization induced by 1 h treatment with 15 mM K+. In pure astrocytes, a rho kinase inhibitor, Y27632 caused the distribution of mitochondria to astrocyte processes without enhancing GLT-1/mitochondrial co-localization, however, in co-cultures, Y27632 abolished mitochondrial:GLT-1 co-localization. Disrupting potential mitochondrial: kinesin interactions using dominant negative TRAK2 did not alter GLT-1 distribution or GLT-1: mitochondrial co-localization. We conclude that the association between GLT-1 and mitochondria is modest, is driven by synaptic activity and dependent on polymerized actin filaments.Mitochondria have limited co-localization with the glutamate transporter GLT-1 in primary astrocytes in culture. Few mitochondria are in the fine processes where GLT-1 is abundant. It is necessary to culture astrocytes with neurones to drive a significant level of co-localization, but co-localization is not further altered by depolarization, manipulating sodium ion gradients or Na/K ATPase activity.
Collapse
Affiliation(s)
- Christopher I Ugbode
- Reading School of Pharmacy, University of Reading, Reading, UK; Bradford School of Pharmacy, University of Bradford, Bradford, UK
| | | | | |
Collapse
|
11
|
Gubellini P, Melon C, Dale E, Doller D, Kerkerian-Le Goff L. Distinct effects of mGlu4 receptor positive allosteric modulators at corticostriatal vs. striatopallidal synapses may differentially contribute to their antiparkinsonian action. Neuropharmacology 2014; 85:166-77. [PMID: 24866785 DOI: 10.1016/j.neuropharm.2014.05.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/21/2014] [Accepted: 05/15/2014] [Indexed: 12/20/2022]
Abstract
Metabotropic glutamate 4 (mGlu4) receptor is a promising target for the treatment of motor deficits in Parkinson's disease (PD). This is due in part to its localization at key basal ganglia (BG) synapses that become hyperactive in this pathology, particularly striatopallidal synapses. In this context, mGlu4 receptor activation using either orthosteric agonists or positive allosteric modulators (PAMs) improves motor symptoms in rodent PD models in certain conditions. However, literature data show that mGlu4 receptor PAMs have no effect at striatopallidal GABAergic synapses (unless combined with an orthosteric agonist) and on the firing activity of pallidal neurons, and fail to provide significant motor improvement in relevant PD models. This questions the mechanistic hypothesis that mGlu4 receptor PAMs should act at striatopallidal synapses to alleviate PD motor symptoms. To shed light on this issue, we performed brain slice electrophysiology experiments. We show that Lu AF21934, an mGlu4 PAM small-molecule probe-compound, was ineffective at striatopallidal synapses at all concentrations tested, while it significantly inhibited corticostriatal synaptic transmission. Similarly, Lu AF21934 did not affect electrophysiology readouts at striatopallidal synapses in the presence of haloperidol or in 6-hydroxydopamine-lesioned rats. Interestingly, co-application of Lu AF21934 with a glutamate transporter inhibitor revealed a significant inhibitory action at striatopallidal synapses. Possibly, this effect could rely on increased level/permanence of glutamate in the synaptic cleft. Such differential efficacy of mGlu4 receptor PAMs at corticostriatal vs. striatopallidal synapses raises several issues regarding the synaptic target(s) of these drugs in the BG, and challenges the mechanisms by which they alleviate motor deficits in experimental PD models.
Collapse
Affiliation(s)
- Paolo Gubellini
- Aix-Marseille Université, CNRS, IBDM UMR7288, 13009 Marseille, France.
| | - Christophe Melon
- Aix-Marseille Université, CNRS, IBDM UMR7288, 13009 Marseille, France
| | - Elena Dale
- Lundbeck Research USA, 215 College Road, Paramus, NJ 07652, USA
| | - Dario Doller
- Lundbeck Research USA, 215 College Road, Paramus, NJ 07652, USA
| | | |
Collapse
|
12
|
Dvorzhak A, Gertler C, Harnack D, Grantyn R. High frequency stimulation of the subthalamic nucleus leads to presynaptic GABA(B)-dependent depression of subthalamo-nigral afferents. PLoS One 2013; 8:e82191. [PMID: 24376521 PMCID: PMC3871646 DOI: 10.1371/journal.pone.0082191] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/31/2013] [Indexed: 12/24/2022] Open
Abstract
Patients with akinesia benefit from chronic high frequency stimulation (HFS) of the subthalamic nucleus (STN). Among the mechanisms contributing to the therapeutic success of HFS-STN might be a suppression of activity in the output region of the basal ganglia. Indeed, recordings in the substantia nigra pars reticulata (SNr) of fully adult mice revealed that HFS-STN consistently produced a reduction of compound glutamatergic excitatory postsynaptic currents at a time when the tetrodotoxin-sensitive components of the local field potentials had already recovered after the high frequency activation. These observations suggest that HFS-STN not only alters action potential conduction on the way towards the SNr but also modifies synaptic transmission within the SNr. A classical conditioning-test paradigm was then designed to better separate the causes from the indicators of synaptic depression. A bipolar platinum-iridium macroelectrode delivered conditioning HFS trains to a larger group of fibers in the STN, while a separate high-ohmic glass micropipette in the rostral SNr provided test stimuli at minimal intensity to single fibers. The conditioning-test interval was set to 100 ms, i.e. the time required to recover the excitability of subthalamo-nigral axons after HFS-STN. The continuity of STN axons passing from the conditioning to the test sites was examined by an action potential occlusion test. About two thirds of the subthalamo-nigral afferents were occlusion-negative, i.e. they were not among the fibers directly activated by the conditioning STN stimulation. Nonetheless, occlusion-negative afferents exhibited signs of presynaptic depression that could be eliminated by blocking GABA(B) receptors with CGP55845 (1 µM). Further analysis of single fiber-activated responses supported the proposal that the heterosynaptic depression of synaptic glutamate release during and after HFS-STN is mainly caused by the tonic release of GABA from co-activated striato-nigral afferents to the SNr. This mechanism would be consistent with a gain-of-function hypothesis of DBS.
Collapse
Affiliation(s)
- Anton Dvorzhak
- Cluster of Excellence NeuroCure, Department of Experimental Neurology, University Medicine Charité, Berlin, Germany
| | - Christoph Gertler
- Department of Experimental Neurology, University Medicine Charité, Berlin, Germany
| | - Daniel Harnack
- Department of Experimental Neurology, University Medicine Charité, Berlin, Germany
| | - Rosemarie Grantyn
- Cluster of Excellence NeuroCure, Department of Experimental Neurology, University Medicine Charité, Berlin, Germany
- * E-mail:
| |
Collapse
|
13
|
Estrada-Sánchez AM, Rebec GV. Role of cerebral cortex in the neuropathology of Huntington's disease. Front Neural Circuits 2013; 7:19. [PMID: 23423362 PMCID: PMC3575072 DOI: 10.3389/fncir.2013.00019] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 01/28/2013] [Indexed: 11/13/2022] Open
Abstract
An expansion of glutamine repeats in the N-terminal domain of the huntingtin protein leads to Huntington's disease (HD), a neurodegenerative condition characterized by the presence of involuntary movements, dementia, and psychiatric disturbances. Evaluation of postmortem HD tissue indicates that the most prominent cell loss occurs in cerebral cortex and striatum, forebrain regions in which cortical pyramidal neurons (CPNs) and striatal medium spiny neurons (MSNs) are the most affected. Subsequent evidence obtained from HD patients and especially from transgenic mouse models of HD indicates that long before neuronal death, patterns of communication between CPNs and MSNs become dysfunctional. In fact, electrophysiological signaling in transgenic HD mice is altered even before the appearance of the HD behavioral phenotype, suggesting that dysfunctional cortical input to the striatum sets the stage for the emergence of HD neurological signs. Striatal MSNs, moreover, project back to cortex via multi-synaptic connections, allowing for even further disruptions in cortical processing. An effective therapeutic strategy for HD, therefore, may lie in understanding the synaptic mechanisms by which it dysregulates the corticostriatal system. Here, we review literature evaluating the molecular, morphological, and physiological alterations in the cerebral cortex, a key component of brain circuitry controlling motor behavior, as they occur in both patients and transgenic HD models.
Collapse
Affiliation(s)
- Ana M Estrada-Sánchez
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
| | | |
Collapse
|
14
|
Maheux J, St-Hilaire M, Voyer D, Tirotta E, Borrelli E, Rouillard C, Rompré PP, Lévesque D. Dopamine D(2) Antagonist-Induced Striatal Nur77 Expression Requires Activation of mGlu5 Receptors by Cortical Afferents. Front Pharmacol 2012; 3:153. [PMID: 22912617 PMCID: PMC3418524 DOI: 10.3389/fphar.2012.00153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/25/2012] [Indexed: 01/03/2023] Open
Abstract
Dopamine D2 receptor antagonists modulate gene transcription in the striatum. However, the molecular mechanism underlying this effect remains elusive. Here we used the expression of Nur77, a transcription factor of the orphan nuclear receptor family, as readout to explore the role of dopamine, glutamate, and adenosine receptors in the effect of a dopamine D2 antagonist in the striatum. First, we investigated D2 antagonist-induced Nur77 mRNA in D2L receptor knockout mice. Surprisingly, deletion of the D2L receptor isoform did not reduce eticlopride-induced upregulation of Nur77 mRNA levels in the striatum. Next, we tested if an ibotenic acid-induced cortical lesion could block the effect of eticlopride on Nur77 expression. Cortical lesions strongly reduced eticlopride-induced striatal upregulation of Nur77 mRNA. Then, we investigated if glutamatergic neurotransmission could modulate eticlopride-induced Nur77 expression. A combination of a metabotropic glutamate type 5 (mGlu5) and adenosine A2A receptor antagonists abolished eticlopride-induced upregulation of Nur77 mRNA levels in the striatum. Direct modulation of Nur77 expression by striatal glutamate and adenosine receptors was confirmed using corticostriatal organotypic cultures. Taken together, these results indicate that blockade of postsynaptic D2 receptors is not sufficient to trigger striatal transcriptional activity and that interaction with corticostriatal presynaptic D2 receptors and subsequent activation of postsynaptic glutamate and adenosine receptors in the striatum is required. Thus, these results uncover an unappreciated role of presynaptic D2 heteroreceptors and support a prominent role of glutamate in the effect of D2 antagonists.
Collapse
Affiliation(s)
- Jérôme Maheux
- Faculté de Pharmacie, Université de Montréal Montréal, QC, Canada
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Napier IA, Mohammadi SA, Christie MJ. Glutamate transporter dysfunction associated with nerve injury-induced pain in mice. J Neurophysiol 2012; 107:649-57. [DOI: 10.1152/jn.00763.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Dysfunction at glutamatergic synapses has been proposed as a mechanism in the development of neuropathic pain. Here we sought to determine whether peripheral nerve injury-induced neuropathic pain results in functional changes to primary afferent synapses. Signs of neuropathic pain as well as an induction of glial fibrillary acidic protein in immunostained spinal cord sections 4 days after partial ligation of the sciatic nerve indicated the induction of neuropathic pain. We found that following nerve injury, no discernable change to kinetics of dl-α-amino-3-hydroxy-5-methylisoxazole-propionic acid (AMPA) or N-methyl-d-aspartate receptor (NMDAR)-mediated evoked excitatory postsynaptic currents (eEPSCs) could be observed in dorsal horn (lamina I/II) neurons compared with those of naïve mice. However, we did find that nerve injury was accompanied by slowed decay of the early phase of eEPSCs in the presence of glutamate transporter inhibition by the competitive nontransportable inhibitor dl-threo-β-benzyloxyaspartic acid (TBOA). Concomitantly, expression patterns for the two major glutamate transporters in the spinal cord, excitatory amino acid transporters (EAAT) 1 and EAAT2, were found to be reduced at this time (4 days postinjury). We then sought to directly determine whether nerve injury results in glutamate spillover to NMDARs at dorsal horn synapses. By employing the use-dependent NMDAR blocker (±)MK-801 to block subsynaptic receptors, we found that although TBOA-induced spillover to extrasynaptic receptors trended to increased activation of these receptors after nerve injury, this was not significant compared with naïve mice. Together, these results suggest the development of neuropathic pain involves subtle changes to glutamate transporter expression and function that could contribute to neuropathic pain during excessive synaptic activity.
Collapse
Affiliation(s)
- Ian A. Napier
- Discipline of Pharmacology, University of Sydney, New South Wales, Australia
| | - Sarasa A. Mohammadi
- Discipline of Pharmacology, University of Sydney, New South Wales, Australia
| | | |
Collapse
|
16
|
Goubard V, Fino E, Venance L. Contribution of astrocytic glutamate and GABA uptake to corticostriatal information processing. J Physiol 2011; 589:2301-19. [PMID: 21486792 DOI: 10.1113/jphysiol.2010.203125] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The astrocytes, active elements of the tripartite synapse, remove most of the neurotransmitter that spills over the synaptic cleft. Neurotransmitter uptake operated by astrocytes contributes to the strength and timing of synaptic inputs. The striatum, the main input nucleus of basal ganglia, extracts pertinent cortical signals from the background noise and relays cortical information toward basal ganglia output structures. We investigated the role of striatal astrocytic uptake in the shaping of corticostriatal transmission.We performed dual patch-clamp recordings of striatal output neuron (the medium-sized spiny neurons, MSNs)–astrocyte pairs while stimulating the somatosensory cortex. Cortical activity evoked robust synaptically activated transporter-mediated currents (STCs) in 78% of the recorded astrocytes. STCs originated equally from the activities of glutamate transporters and GABA transporters (GATs). Astrocytic STCs reflected here a presynaptic release of neurotransmitters. STCs displayed a large magnitude associated with fast kinetics, denoting an efficient neurotransmitter clearance at the corticostriatal pathway. Inhibition of glutamate transporters type-1 (GLT-1) and GATs decreased the corticostriatal synaptic transmission, through, respectively, desensitization of AMPA receptors and activation of GABAA receptor. STCs displayed a bidirectional short-term plasticity (facilitation for paired-pulse intervals less than 100 ms and depression up to 1 s).We report a genuine facilitation of STCs for high-frequency cortical activity, which could strengthen the detection properties of cortical activity operated by MSNs. MSN EPSCs showed a triphasic short-term plasticity, which was modified by the blockade of GLT-1 or GATs. We show here that neurotransmitter uptake by astrocytes plays a key role in the corticostriatal information processing.
Collapse
Affiliation(s)
- Valérie Goubard
- Dynamic and Pathophysiology of Neuronal Networks, INSERM U667, College de France, 75005 Paris, France
| | | | | |
Collapse
|
17
|
Gubert P, Ávila DS, Bridi JC, Saurin S, Lugokenski TH, Villarinho JG, Fachinetto R, Pereira ME, Ferreira J, da Rocha JBT, Soares FAA. Low concentrations of methamidophos do not alter AChE activity but modulate neurotransmitters uptake in hippocampus and striatum in vitro. Life Sci 2011; 88:89-95. [DOI: 10.1016/j.lfs.2010.10.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 09/25/2010] [Accepted: 10/26/2010] [Indexed: 11/24/2022]
|
18
|
Napolitano F, Pasqualetti M, Usiello A, Santini E, Pacini G, Sciamanna G, Errico F, Tassone A, Di Dato V, Martella G, Cuomo D, Fisone G, Bernardi G, Mandolesi G, Mercuri NB, Standaert DG, Pisani A. Dopamine D2 receptor dysfunction is rescued by adenosine A2A receptor antagonism in a model of DYT1 dystonia. Neurobiol Dis 2010; 38:434-45. [PMID: 20227500 DOI: 10.1016/j.nbd.2010.03.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/04/2010] [Accepted: 03/04/2010] [Indexed: 11/27/2022] Open
Abstract
DYT1 dystonia is an inherited disease linked to mutation in the TOR1A gene encoding for the protein torsinA. Although the mechanism by which this genetic alteration leads to dystonia is unclear, multiple lines of clinical evidence suggest a link between dystonia and a reduced dopamine D2 receptor (D2R) availability. Based on this evidence, herein we carried out a comprehensive analysis of electrophysiological, behavioral and signaling correlates of D2R transmission in transgenic mice with the DYT1 dystonia mutation. Electrophysiological recordings from nigral dopaminergic neurons showed a normal responsiveness to D2-autoreceptor function. Conversely, postsynaptic D2R function in hMT mice was impaired, as suggested by the inability of a D2R agonist to re-establish normal corticostriatal synaptic plasticity and supported by the reduced sensitivity to haloperidol-induced catalepsy. Although an in situ hybridization analysis showed normal D1R and D2R mRNA expression levels in the striata of hMT mice, we found a significant decrease of D2R protein, coupled to a reduced ability of D2Rs to activate their cognate Go/i proteins. Of relevance, we found that pharmacological blockade of adenosine A2A receptors (A2ARs) fully restored the impairment of synaptic plasticity observed in hMT mice. Together, our findings demonstrate an important link between torsinA mutation and D2R dysfunction and suggest that A2AR antagonism is able to counteract the deficit in D2R-mediated transmission observed in mutant mice, opening new perspectives for the treatment of this movement disorder.
Collapse
|
19
|
Borisova T, Krisanova N, Sivko R, Borysov A. Cholesterol depletion attenuates tonic release but increases the ambient level of glutamate in rat brain synaptosomes. Neurochem Int 2010; 56:466-78. [DOI: 10.1016/j.neuint.2009.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 12/07/2009] [Accepted: 12/11/2009] [Indexed: 10/20/2022]
|
20
|
Ciliary neurotrophic factor protects striatal neurons against excitotoxicity by enhancing glial glutamate uptake. PLoS One 2010; 5:e8550. [PMID: 20062544 PMCID: PMC2798716 DOI: 10.1371/journal.pone.0008550] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 12/09/2009] [Indexed: 11/19/2022] Open
Abstract
Ciliary neurotrophic factor (CNTF) is a potent neuroprotective cytokine in different animal models of glutamate-induced excitotoxicity, although its action mechanisms are still poorly characterized. We tested the hypothesis that an increased function of glial glutamate transporters (GTs) could underlie CNTF-mediated neuroprotection. We show that neuronal loss induced by in vivo striatal injection of the excitotoxin quinolinic acid (QA) was significantly reduced (by ∼75%) in CNTF-treated animals. In striatal slices, acute QA application dramatically inhibited corticostriatal field potentials (FPs), whose recovery was significantly higher in CNTF rats compared to controls (∼40% vs. ∼7%), confirming an enhanced resistance to excitotoxicity. The GT inhibitor dl-threo-β-benzyloxyaspartate greatly reduced FP recovery in CNTF rats, supporting the role of GT in CNTF-mediated neuroprotection. Whole-cell patch-clamp recordings from striatal medium spiny neurons showed no alteration of basic properties of striatal glutamatergic transmission in CNTF animals, but the increased effect of a low-affinity competitive glutamate receptor antagonist (γ-d-glutamylglycine) also suggested an enhanced GT function. These data strongly support our hypothesis that CNTF is neuroprotective via an increased function of glial GTs, and further confirms the therapeutic potential of CNTF for the clinical treatment of progressive neurodegenerative diseases involving glutamate overflow.
Collapse
|