1
|
Mao C, Zhang Y, Jiang J, Qin R, Ye Q, Zhu X, Wu J. Magnetic Resonance Imaging Biomarkers of Punding in Parkinson's Disease. Brain Sci 2023; 13:1423. [PMID: 37891792 PMCID: PMC10605844 DOI: 10.3390/brainsci13101423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/15/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
Punding is a rare condition triggered by dopaminergic therapy in Parkinson's disease (PD), characterized by a complex, excessive, repetitive, and purposeless abnormal movement, and its pathogenesis remains unclear. We aimed to assess the brain structure alterations related to punding by using multipametric magnetic resonance imaging (MRI). Thirty-eight PD patients (19 with punding and 19 without punding) from the Parkinson's Progression Marker Initiative (PPMI) were included in this study. Cortical thickness was assessed with FreeSurfer, and the integrity of white matter fiber tracts and network topologies were analyzed by using FMRIB Software Library (FSL) and Pipeline for Analyzing braiN Diffusion imAges (PANDA). PD patients with punding showed a higher apathy score and more severe cortical atrophy in the left superior parietal, right inferior parietal, and right superior frontal gyrus, and worse integrity of the right cingulum cingulate tract compared to those without punding. On the other hand, no significant difference in structural network topologies was detected between the two groups. These data suggest that the specific area of destruction may be an MRI biomarker of punding risk, and these findings may have important implications for understanding the neural mechanisms of punding in PD.
Collapse
Affiliation(s)
- Chenglu Mao
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Yang Zhang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Jialiu Jiang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Ruomeng Qin
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Qing Ye
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Xiaolei Zhu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| | - Jiayong Wu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; (C.M.); (Y.Z.); (J.J.); (R.Q.); (Q.Y.); (X.Z.)
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China
| |
Collapse
|
2
|
Knowles R, Dehorter N, Ellender T. From Progenitors to Progeny: Shaping Striatal Circuit Development and Function. J Neurosci 2021; 41:9483-9502. [PMID: 34789560 PMCID: PMC8612473 DOI: 10.1523/jneurosci.0620-21.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 12/29/2022] Open
Abstract
Understanding how neurons of the striatum are formed and integrate into complex synaptic circuits is essential to provide insight into striatal function in health and disease. In this review, we summarize our current understanding of the development of striatal neurons and associated circuits with a focus on their embryonic origin. Specifically, we address the role of distinct types of embryonic progenitors, found in the proliferative zones of the ganglionic eminences in the ventral telencephalon, in the generation of diverse striatal interneurons and projection neurons. Indeed, recent evidence would suggest that embryonic progenitor origin dictates key characteristics of postnatal cells, including their neurochemical content, their location within striatum, and their long-range synaptic inputs. We also integrate recent observations regarding embryonic progenitors in cortical and other regions and discuss how this might inform future research on the ganglionic eminences. Last, we examine how embryonic progenitor dysfunction can alter striatal formation, as exemplified in Huntington's disease and autism spectrum disorder, and how increased understanding of embryonic progenitors can have significant implications for future research directions and the development of improved therapeutic options.SIGNIFICANCE STATEMENT This review highlights recently defined novel roles for embryonic progenitor cells in shaping the functional properties of both projection neurons and interneurons of the striatum. It outlines the developmental mechanisms that guide neuronal development from progenitors in the embryonic ganglionic eminences to progeny in the striatum. Where questions remain open, we integrate observations from cortex and other regions to present possible avenues for future research. Last, we provide a progenitor-centric perspective onto both Huntington's disease and autism spectrum disorder. We suggest that future investigations and manipulations of embryonic progenitor cells in both research and clinical settings will likely require careful consideration of their great intrinsic diversity and neurogenic potential.
Collapse
Affiliation(s)
- Rhys Knowles
- The John Curtin School of Medical Research, The Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Nathalie Dehorter
- The John Curtin School of Medical Research, The Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Tommas Ellender
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
- Department of Biomedical Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| |
Collapse
|
3
|
Maingret F, Groc L. Characterization of the Functional Cross-Talk between Surface GABA A and Dopamine D5 Receptors. Int J Mol Sci 2021; 22:4867. [PMID: 34064454 PMCID: PMC8125140 DOI: 10.3390/ijms22094867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 01/17/2023] Open
Abstract
The γ-aminobutyric acid type A receptor (GABAAR) plays a major role in fast inhibitory synaptic transmission and is highly regulated by the neuromodulator dopamine. In this aspect, most of the attention has been focused on the classical intracellular signaling cascades following dopamine G-protein-coupled receptor activation. Interestingly, the GABAAR and dopamine D5 receptor (D5R) have been shown to physically interact in the hippocampus, but whether a functional cross-talk occurs is still debated. In the present study, we use a combination of imaging and single nanoparticle tracking in live hippocampal neurons to provide evidence that GABAARs and D5Rs form dynamic surface clusters. Disrupting the GABAAR-D5R interaction with a competing peptide leads to an increase in the diffusion coefficient and the explored area of both receptors, and a drop in immobile synaptic GABAARs. By means of patch-clamp recordings, we show that this fast lateral redistribution of surface GABAARs correlates with a robust depression in the evoked GABAergic currents. Strikingly, it also shifts in time the expression of long-term potentiation at glutamatergic synapses. Together, our data both set the plasma membrane as the primary stage of a functional interplay between GABAAR and D5R, and uncover a non-canonical role in regulating synaptic transmission.
Collapse
Affiliation(s)
- François Maingret
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
| | - Laurent Groc
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
| |
Collapse
|
4
|
van Heusden F, Macey-Dare A, Gordon J, Krajeski R, Sharott A, Ellender T. Diversity in striatal synaptic circuits arises from distinct embryonic progenitor pools in the ventral telencephalon. Cell Rep 2021; 35:109041. [PMID: 33910016 PMCID: PMC8097690 DOI: 10.1016/j.celrep.2021.109041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 01/29/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Synaptic circuits in the brain are precisely organized, but the processes that govern this precision are poorly understood. Here, we explore how distinct embryonic neural progenitor pools in the lateral ganglionic eminence contribute to neuronal diversity and synaptic circuit connectivity in the mouse striatum. In utero labeling of Tα1-expressing apical intermediate progenitors (aIP), as well as other progenitors (OP), reveals that both progenitors generate direct and indirect pathway spiny projection neurons (SPNs) with similar electrophysiological and anatomical properties and are intermingled in medial striatum. Subsequent optogenetic circuit-mapping experiments demonstrate that progenitor origin significantly impacts long-range excitatory input strength, with medial prefrontal cortex preferentially driving aIP-derived SPNs and visual cortex preferentially driving OP-derived SPNs. In contrast, the strength of local inhibitory inputs among SPNs is controlled by birthdate rather than progenitor origin. Combined, these results demonstrate distinct roles for embryonic progenitor origin in shaping neuronal and circuit properties of the postnatal striatum. The Tα1 promoter distinguishes two embryonic progenitor pools in the LGE Both pools generate intermixed spiny projection neurons in dorsomedial striatum Excitatory cortical inputs are biased toward SPNs of different embryonic origin Neurogenic stage rather impacts local inhibitory connections among SPNs
Collapse
Affiliation(s)
- Fran van Heusden
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Anežka Macey-Dare
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Jack Gordon
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Rohan Krajeski
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | | | - Tommas Ellender
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.
| |
Collapse
|
5
|
Boccalaro IL, Schwerdel C, Cristiá-Lara L, Fritschy JM, Rubi L. Dopamine depletion induces neuron-specific alterations of GABAergic transmission in the mouse striatum. Eur J Neurosci 2020; 52:3353-3374. [PMID: 32599671 DOI: 10.1111/ejn.14886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 11/28/2022]
Abstract
Lack of dopamine (DA) in the striatum and the consequential dysregulation of thalamocortical circuits are major causes of motor impairments in Parkinson's disease. The striatum receives multiple cortical and subcortical afferents. Its role in movement control and motor skills learning is regulated by DA from the nigrostriatal pathway. In Parkinson's disease, DA loss affects striatal network activity and induces a functional imbalance of its output pathways, impairing thalamocortical function. Striatal projection neurons are GABAergic and form two functionally antagonistic pathways: the direct pathway, originating from DA receptor type 1-expressing medium spiny neurons (D1 R-MSN), and the indirect pathway, from D2 R-MSN. Here, we investigated whether DA depletion in mouse striatum also affects GABAergic function. We recorded GABAergic miniature IPSCs (mIPSC) and tonic inhibition from D1 R- and D2 R-MSN and used immunohistochemical labeling to study GABAA R function and subcellular distribution in DA-depleted and control mice. We observed slower decay kinetics and increased tonic inhibition in D1 R-MSN, while D2 R-MSN had increased mIPSC frequency after DA depletion. Perisomatic synapses containing the GABAA R subunits α1 or α2 were not affected, but there was a strong decrease in non-synaptic GABAA Rs containing these subunits, suggesting altered receptor trafficking. To broaden these findings, we also investigated GABAA Rs in GABAergic and cholinergic interneurons and found cell type-specific alterations in receptor distribution, likely reflecting changes in connectivity. Our results reveal that chronic DA depletion alters striatal GABAergic transmission, thereby affecting cellular and circuit activity. These alterations either result from pathological changes or represent a compensatory mechanism to counteract imbalance of output pathways.
Collapse
Affiliation(s)
- Ida Luisa Boccalaro
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Cornelia Schwerdel
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | | | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Lena Rubi
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| |
Collapse
|
6
|
Kim JH, Ki Y, Lee H, Hur MS, Baik B, Hur JH, Nam D, Lim C. The voltage-gated potassium channel Shaker promotes sleep via thermosensitive GABA transmission. Commun Biol 2020; 3:174. [PMID: 32296133 PMCID: PMC7160125 DOI: 10.1038/s42003-020-0902-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
Genes and neural circuits coordinately regulate animal sleep. However, it remains elusive how these endogenous factors shape sleep upon environmental changes. Here, we demonstrate that Shaker (Sh)-expressing GABAergic neurons projecting onto dorsal fan-shaped body (dFSB) regulate temperature-adaptive sleep behaviors in Drosophila. Loss of Sh function suppressed sleep at low temperature whereas light and high temperature cooperatively gated Sh effects on sleep. Sh depletion in GABAergic neurons partially phenocopied Sh mutants. Furthermore, the ionotropic GABA receptor, Resistant to dieldrin (Rdl), in dFSB neurons acted downstream of Sh and antagonized its sleep-promoting effects. In fact, Rdl inhibited the intracellular cAMP signaling of constitutively active dopaminergic synapses onto dFSB at low temperature. High temperature silenced GABAergic synapses onto dFSB, thereby potentiating the wake-promoting dopamine transmission. We propose that temperature-dependent switching between these two synaptic transmission modalities may adaptively tune the neural property of dFSB neurons to temperature shifts and reorganize sleep architecture for animal fitness. Ji-hyung Kim and Yoonhee Ki et al. show that low temperatures suppress sleep in Drosophila by increasing GABA transmission in Shaker-expressing GABAergic neurons projecting onto the dorsal fan-shaped body, while high temperatures potentiate dopamine-induced arousal by reducing GABA transmission. This study highlights a role for Shaker in sleep modulation via a temperature-dependent switch in GABA signaling.
Collapse
Affiliation(s)
- Ji-Hyung Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yoonhee Ki
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hoyeon Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Moon Seong Hur
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Bukyung Baik
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jin-Hoe Hur
- UNIST Optical Biomed Imaging Center, UNIST, Ulsan, 44919, Republic of Korea
| | - Dougu Nam
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Chunghun Lim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
| |
Collapse
|
7
|
Geisler S, Schöpf CL, Stanika R, Kalb M, Campiglio M, Repetto D, Traxler L, Missler M, Obermair GJ. Presynaptic α 2δ-2 Calcium Channel Subunits Regulate Postsynaptic GABA A Receptor Abundance and Axonal Wiring. J Neurosci 2019; 39:2581-2605. [PMID: 30683685 PMCID: PMC6445987 DOI: 10.1523/jneurosci.2234-18.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/03/2019] [Accepted: 01/08/2019] [Indexed: 01/26/2023] Open
Abstract
Presynaptic α2δ subunits of voltage-gated calcium channels regulate channel abundance and are involved in glutamatergic synapse formation. However, little is known about the specific functions of the individual α2δ isoforms and their role in GABAergic synapses. Using primary neuronal cultures of embryonic mice of both sexes, we here report that presynaptic overexpression of α2δ-2 in GABAergic synapses strongly increases clustering of postsynaptic GABAARs. Strikingly, presynaptic α2δ-2 exerts the same effect in glutamatergic synapses, leading to a mismatched localization of GABAARs. This mismatching is caused by an aberrant wiring of glutamatergic presynaptic boutons with GABAergic postsynaptic positions. The trans-synaptic effect of α2δ-2 is independent of the prototypical cell-adhesion molecules α-neurexins (α-Nrxns); however, α-Nrxns together with α2δ-2 can modulate postsynaptic GABAAR abundance. Finally, exclusion of the alternatively spliced exon 23 of α2δ-2 is essential for the trans-synaptic mechanism. The novel function of α2δ-2 identified here may explain how abnormal α2δ subunit expression can cause excitatory-inhibitory imbalance often associated with neuropsychiatric disorders.SIGNIFICANCE STATEMENT Voltage-gated calcium channels regulate important neuronal functions such as synaptic transmission. α2δ subunits modulate calcium channels and are emerging as regulators of brain connectivity. However, little is known about how individual α2δ subunits contribute to synapse specificity. Here, we show that presynaptic expression of a single α2δ variant can modulate synaptic connectivity and the localization of inhibitory postsynaptic receptors. Our findings provide basic insights into the development of specific synaptic connections between nerve cells and contribute to our understanding of normal nerve cell functions. Furthermore, the identified mechanism may explain how an altered expression of calcium channel subunits can result in aberrant neuronal wiring often associated with neuropsychiatric disorders such as autism or schizophrenia.
Collapse
Affiliation(s)
- Stefanie Geisler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Clemens L Schöpf
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Ruslan Stanika
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marcus Kalb
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marta Campiglio
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Larissa Traxler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| |
Collapse
|
8
|
Nicholson MW, Sweeney A, Pekle E, Alam S, Ali AB, Duchen M, Jovanovic JN. Diazepam-induced loss of inhibitory synapses mediated by PLCδ/ Ca 2+/calcineurin signalling downstream of GABAA receptors. Mol Psychiatry 2018; 23:1851-1867. [PMID: 29904150 PMCID: PMC6232101 DOI: 10.1038/s41380-018-0100-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 04/09/2018] [Accepted: 05/01/2018] [Indexed: 11/29/2022]
Abstract
Benzodiazepines facilitate the inhibitory actions of GABA by binding to γ-aminobutyric acid type A receptors (GABAARs), GABA-gated chloride/bicarbonate channels, which are the key mediators of transmission at inhibitory synapses in the brain. This activity underpins potent anxiolytic, anticonvulsant and hypnotic effects of benzodiazepines in patients. However, extended benzodiazepine treatments lead to development of tolerance, a process which, despite its important therapeutic implications, remains poorly characterised. Here we report that prolonged exposure to diazepam, the most widely used benzodiazepine in clinic, leads to a gradual disruption of neuronal inhibitory GABAergic synapses. The loss of synapses and the preceding, time- and dose-dependent decrease in surface levels of GABAARs, mediated by dynamin-dependent internalisation, were blocked by Ro 15-1788, a competitive benzodiazepine antagonist, and bicuculline, a competitive GABA antagonist, indicating that prolonged enhancement of GABAAR activity by diazepam is integral to the underlying molecular mechanism. Characterisation of this mechanism has revealed a metabotropic-type signalling downstream of GABAARs, involving mobilisation of Ca2+ from the intracellular stores and activation of the Ca2+/calmodulin-dependent phosphatase calcineurin, which, in turn, dephosphorylates GABAARs and promotes their endocytosis, leading to disassembly of inhibitory synapses. Furthermore, functional coupling between GABAARs and Ca2+ stores was sensitive to phospholipase C (PLC) inhibition by U73122, and regulated by PLCδ, a PLC isoform found in direct association with GABAARs. Thus, a PLCδ/Ca2+/calcineurin signalling cascade converts the initial enhancement of GABAARs by benzodiazepines to a long-term downregulation of GABAergic synapses, this potentially underpinning the development of pharmacological and behavioural tolerance to these widely prescribed drugs.
Collapse
Affiliation(s)
| | - Aaron Sweeney
- UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Eva Pekle
- UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Sabina Alam
- UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Afia B Ali
- UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Michael Duchen
- Neuroscience, Physiology and Pharmacology, University College London, WC1E 6BT, London, UK
| | | |
Collapse
|
9
|
Garret M, Du Z, Chazalon M, Cho YH, Baufreton J. Alteration of GABAergic neurotransmission in Huntington's disease. CNS Neurosci Ther 2018; 24:292-300. [PMID: 29464851 DOI: 10.1111/cns.12826] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 12/16/2022] Open
Abstract
Hereditary Huntington's disease (HD) is characterized by cell dysfunction and death in the brain, leading to progressive cognitive, psychiatric, and motor impairments. Despite molecular and cellular descriptions of the effects of the HD mutation, no effective pharmacological treatment is yet available. In addition to well-established alterations of glutamatergic and dopaminergic neurotransmitter systems, it is becoming clear that the GABAergic systems are also impaired in HD. GABA is the major inhibitory neurotransmitter in the brain, and GABAergic neurotransmission has been postulated to be modified in many neurological and psychiatric diseases. In addition, GABAergic neurotransmission is the target of many drugs that are in wide clinical use. Here, we summarize data demonstrating the occurrence of alterations of GABAergic markers in the brain of HD carriers as well as in rodent models of the disease. In particular, we pinpoint HD-related changes in the expression of GABAA receptors (GABAA Rs). On the basis that a novel GABA pharmacology of GABAA Rs established with more selective drugs is emerging, we argue that clinical treatments acting specifically on GABAergic neurotransmission may be an appropriate strategy for improving symptoms linked to the HD mutation.
Collapse
Affiliation(s)
- Maurice Garret
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Zhuowei Du
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Marine Chazalon
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
| | - Yoon H Cho
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Jérôme Baufreton
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
| |
Collapse
|
10
|
Du Z, Tertrais M, Courtand G, Leste-Lasserre T, Cardoit L, Masmejean F, Halgand C, Cho YH, Garret M. Differential Alteration in Expression of Striatal GABA AR Subunits in Mouse Models of Huntington's Disease. Front Mol Neurosci 2017; 10:198. [PMID: 28676743 PMCID: PMC5476702 DOI: 10.3389/fnmol.2017.00198] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/06/2017] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is a neurodegenerative disorder characterized by progressive motor symptoms that are preceded by cognitive deficits and is considered as a disorder that primarily affects forebrain striatal neurons. To gain a better understanding of the molecular and cellular mechanisms associated with disease progression, we analyzed the expression of proteins involved in GABAergic neurotransmission in the striatum of the R6/1 transgenic mouse model. Western blot, quantitative PCR and immunohistochemical analyses were conducted on male R6/1 mice and age-matched wild type littermates. Analyses were performed on 2 and 6 month-old animals, respectively, before and after the onset of motor symptoms. Expression of GAD 67, GAD 65, NL2, or gephyrin proteins, involved in GABA synthesis or synapse formation did not display major changes. In contrast, expression of α1, α3 and α5 GABAAR subunits was increased while the expression of δ was decreased, suggesting a change in tonic- and phasic inhibitory transmission. Western blot analysis of the striatum from 8 month-old Hdh Q111, a knock-in mouse model of HD with mild deficits, confirmed the α1 subunit increased expression. From immunohistochemical analyses, we also found that α1 subunit expression is increased in medium-sized spiny projection neurons (MSN) and decreased in parvalbumin (PV)-expressing interneurons at 2 and 6 months in R6/1 mice. Moreover, α2 subunit labeling on the PV and MSN cell membranes was increased at 2 months and decreased at 6 months. Alteration of gene expression in the striatum and modification of GABAA receptor subtypes in both interneurons and projection neurons suggested that HD mutation has a profound effect on synaptic plasticity at an early stage, before the onset of motor symptoms. These results also indicate that cognitive and other behavioral deficits may be associated with changes in GABAergic neurotransmission that consequently could be a relevant target for early therapeutic treatment.
Collapse
Affiliation(s)
- Zhuowei Du
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Margot Tertrais
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Gilles Courtand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Thierry Leste-Lasserre
- Institut National de la Santé et de la Recherche Médicale, Neurocentre Magendie, U862, Physiopathologie de la Plasticité NeuronaleBordeaux, France.,Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, University of BordeauxBordeaux, France
| | - Laura Cardoit
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Frédérique Masmejean
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Christophe Halgand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Yoon H Cho
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Maurice Garret
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| |
Collapse
|
11
|
Clark AR, Carter AB, Hager LE, Price EM. In Vivo Neural Tissue Engineering: Cylindrical Biocompatible Hydrogels That Create New Neural Tracts in the Adult Mammalian Brain. Stem Cells Dev 2016; 25:1109-18. [PMID: 27295980 DOI: 10.1089/scd.2016.0069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Individuals with neurodegenerative disorders or brain injury have few treatment options and it has been proposed that endogenous adult neural stem cells can be harnessed to repopulate dysfunctional nonneurogenic regions of the brain. We have accomplished this through the development of rationally designed hydrogel implants that recruit endogenous cells from the adult subventricular zone to create new relatively long tracts of neuroblasts. These implants are biocompatible and biodegradable cylindrical hydrogels consisting of fibrin and immobilized neurotrophic factors. When implanted into rat brain such that the cylinder intersected the migratory path of endogenous neural progenitors (the rostral migratory stream) and led into the nonneurogenic striatum, we observed a robust neurogenic response in the form of migrating neuroblasts with long (>100 μm) complex neurites. The location of these new neural cells in the striatum was directly coincident with the original track of the fibrin implant, which itself had completely degraded, and covered a significant area and distance (>2.5 mm). We also observed a significant number of neuroblasts in the striatal region between the implant track and the lateral ventricle. When these fibrin cylinders were implanted into hemiparkinson rats, correction of parkinsonian behavior was observed. There were no obvious behavioral, inflammatory or tumorigenic sequelae as a consequence of the implants. In conclusion, we have successfully engineered neural tissue in vivo, using neurogenic biomaterials cast into a unique cylindrical architecture. These results represent a novel approach to efficiently induce neurogenesis in a controlled and targeted manner, which may lead toward a new therapeutic modality for neurological disorders.
Collapse
Affiliation(s)
- Amanda R Clark
- Department of Biology, Marshall University , Huntington, West Virginia
| | - Arrin B Carter
- Department of Biology, Marshall University , Huntington, West Virginia
| | - Lydia E Hager
- Department of Biology, Marshall University , Huntington, West Virginia
| | - Elmer M Price
- Department of Biology, Marshall University , Huntington, West Virginia
| |
Collapse
|
12
|
Metformin Prevented Dopaminergic Neurotoxicity Induced by 3,4-Methylenedioxymethamphetamine Administration. Neurotox Res 2016; 30:101-9. [DOI: 10.1007/s12640-016-9633-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 05/19/2016] [Accepted: 05/21/2016] [Indexed: 01/31/2023]
|
13
|
Brown LE, Nicholson MW, Arama JE, Mercer A, Thomson AM, Jovanovic JN. γ-Aminobutyric Acid Type A (GABAA) Receptor Subunits Play a Direct Structural Role in Synaptic Contact Formation via Their N-terminal Extracellular Domains. J Biol Chem 2016; 291:13926-13942. [PMID: 27129275 PMCID: PMC4933154 DOI: 10.1074/jbc.m116.714790] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 11/17/2022] Open
Abstract
The establishment of cell-cell contacts between presynaptic GABAergic neurons and their postsynaptic targets initiates the process of GABAergic synapse formation. GABAA receptors (GABAARs), the main postsynaptic receptors for GABA, have been recently demonstrated to act as synaptogenic proteins that can single-handedly induce the formation and functional maturation of inhibitory synapses. To establish how the subunit composition of GABAARs influences their ability to induce synaptogenesis, a co-culture model system incorporating GABAergic medium spiny neurons and the HEK293 cells, stably expressing different combinations of receptor subunits, was developed. Analyses of HEK293 cell innervation by medium spiny neuron axons using immunocytochemistry, activity-dependent labeling, and electrophysiology have indicated that the γ2 subunit is required for the formation of active synapses and that its effects are influenced by the type of α/β subunits incorporated into the functional receptor. To further characterize this process, the large N-terminal extracellular domains (ECDs) of α1, α2, β2, and γ2 subunits were purified using the baculovirus/Sf9 cell system. When these proteins were applied to the co-cultures of MSNs and α1/β2/γ2-expressing HEK293 cells, the α1, β2, or γ2 ECD each caused a significant reduction in contact formation, in contrast to the α2 ECD, which had no effect. Together, our experiments indicate that the structural role of GABAARs in synaptic contact formation is determined by their subunit composition, with the N-terminal ECDs of each of the subunits directly participating in interactions between the presynaptic and postsynaptic elements, suggesting the these interactions are multivalent and specific.
Collapse
Affiliation(s)
- Laura E Brown
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Martin W Nicholson
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Jessica E Arama
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Audrey Mercer
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Alex M Thomson
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Jasmina N Jovanovic
- Research Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom.
| |
Collapse
|
14
|
Frau L, Costa G, Porceddu PF, Khairnar A, Castelli MP, Ennas MG, Madeddu C, Wardas J, Morelli M. Influence of caffeine on 3,4-methylenedioxymethamphetamine-induced dopaminergic neuron degeneration and neuroinflammation is age-dependent. J Neurochem 2015; 136:148-62. [DOI: 10.1111/jnc.13377] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/02/2015] [Accepted: 09/03/2015] [Indexed: 02/03/2023]
Affiliation(s)
- Lucia Frau
- Department of Biomedical Sciences; Section of Neuropsychopharmacology; University of Cagliari; Cagliari Italy
| | - Giulia Costa
- Department of Biomedical Sciences; Section of Neuropsychopharmacology; University of Cagliari; Cagliari Italy
| | - Pier Francesca Porceddu
- Department of Biomedical Sciences; Section of Neuropsychopharmacology; University of Cagliari; Cagliari Italy
| | - Amit Khairnar
- Applied Neuroscience Research Group; CEITEC - Central European Institute of Technology; Masaryk University; Brno Czech Republic
| | - Maria Paola Castelli
- Department of Biomedical Sciences; Section of Neuroscience and Clinical Pharmacology; University of Cagliari; Monserrato (CA) Italy
| | - Maria Grazia Ennas
- Department of Biomedical Sciences; Section of Neuroscience and Clinical Pharmacology; University of Cagliari; Monserrato (CA) Italy
| | - Camilla Madeddu
- Department of Biomedical Sciences; Section of Neuroscience and Clinical Pharmacology; University of Cagliari; Monserrato (CA) Italy
| | - Jadwiga Wardas
- Department of Neuropsychopharmacology; Institute of Pharmacology; Polish Academy of Sciences; Krakow Poland
| | - Micaela Morelli
- Department of Biomedical Sciences; Section of Neuropsychopharmacology; University of Cagliari; Cagliari Italy
- CNR; Institute of Neuroscience; Cagliari Italy
| |
Collapse
|
15
|
Arama J, Abitbol K, Goffin D, Fuchs C, Sihra TS, Thomson AM, Jovanovic JN. GABAA receptor activity shapes the formation of inhibitory synapses between developing medium spiny neurons. Front Cell Neurosci 2015; 9:290. [PMID: 26300728 PMCID: PMC4526800 DOI: 10.3389/fncel.2015.00290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/15/2015] [Indexed: 11/30/2022] Open
Abstract
Basal ganglia play an essential role in motor coordination and cognitive functions. The GABAergic medium spiny neurons (MSNs) account for ~95% of all the neurons in this brain region. Central to the normal functioning of MSNs is integration of synaptic activity arriving from the glutamatergic corticostriatal and thalamostriatal afferents, with synaptic inhibition mediated by local interneurons and MSN axon collaterals. In this study we have investigated how the specific types of GABAergic synapses between the MSNs develop over time, and how the activity of GABAA receptors (GABAARs) influences this development. Isolated embryonic (E17) MSNs form a homogenous population in vitro and display spontaneous synaptic activity and functional properties similar to their in vivo counterparts. In dual whole-cell recordings of synaptically connected pairs of MSNs, action potential (AP)-activated synaptic events were detected between 7 and 14 days in vitro (DIV), which coincided with the shift in GABAAR operation from depolarization to hyperpolarization, as detected indirectly by intracellular calcium imaging. In parallel, the predominant subtypes of inhibitory synapses, which innervate dendrites of MSNs and contain GABAAR α1 or α2 subunits, underwent distinct changes in the size of postsynaptic clusters, with α1 becoming smaller and α2 larger over time, while both the percentage and the size of mixed α1/α2-postsynaptic clusters were increased. When activity of GABAARs was under chronic blockade between 4–7 DIV, the structural properties of these synapses remained unchanged. In contrast, chronic inhibition of GABAARs between 7–14 DIV led to reduction in size of α1- and α1/α2-postsynaptic clusters and a concomitant increase in number and size of α2-postsynaptic clusters. Thus, the main subtypes of GABAergic synapses formed by MSNs are regulated by GABAAR activity, but in opposite directions, and thus appear to be driven by different molecular mechanisms.
Collapse
Affiliation(s)
- Jessica Arama
- UCL School of Pharmacy, University College London London, UK
| | - Karine Abitbol
- UCL School of Pharmacy, University College London London, UK
| | - Darren Goffin
- UCL School of Pharmacy, University College London London, UK
| | - Celine Fuchs
- UCL School of Pharmacy, University College London London, UK
| | - Talvinder S Sihra
- Neuroscience, Physiology and Pharmacology, UCL Division of Biosciences, University College London London, UK
| | - Alex M Thomson
- UCL School of Pharmacy, University College London London, UK
| | | |
Collapse
|
16
|
Penrod RD, Campagna J, Panneck T, Preese L, Lanier LM. The presence of cortical neurons in striatal-cortical co-cultures alters the effects of dopamine and BDNF on medium spiny neuron dendritic development. Front Cell Neurosci 2015; 9:269. [PMID: 26257605 PMCID: PMC4507052 DOI: 10.3389/fncel.2015.00269] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/29/2015] [Indexed: 12/21/2022] Open
Abstract
Medium spiny neurons (MSNs) are the major striatal neuron and receive synaptic input from both glutamatergic and dopaminergic afferents. These synapses are made on MSN dendritic spines, which undergo density and morphology changes in association with numerous disease and experience-dependent states. Despite wide interest in the structure and function of mature MSNs, relatively little is known about MSN development. Furthermore, most in vitro studies of MSN development have been done in simple striatal cultures that lack any type of non-autologous synaptic input, leaving open the question of how MSN development is affected by a complex environment that includes other types of neurons, glia, and accompanying secreted and cell-associated cues. Here we characterize the development of MSNs in striatal-cortical co-culture, including quantitative morphological analysis of dendritic arborization and spine development, describing progressive changes in density and morphology of developing spines. Overall, MSN growth is much more robust in the striatal-cortical co-culture compared to striatal mono-culture. Inclusion of dopamine (DA) in the co-culture further enhances MSN dendritic arborization and spine density, but the effects of DA on dendritic branching are only significant at later times in development. In contrast, exogenous Brain Derived Neurotrophic Factor (BDNF) has only a minimal effect on MSN development in the co-culture, but significantly enhances MSN dendritic arborization in striatal mono-culture. Importantly, inhibition of NMDA receptors in the co-culture significantly enhances the effect of exogenous BDNF, suggesting that the efficacy of BDNF depends on the cellular environment. Combined, these studies identify specific periods of MSN development that may be particularly sensitive to perturbation by external factors and demonstrate the importance of studying MSN development in a complex signaling environment.
Collapse
Affiliation(s)
- Rachel D Penrod
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA ; Graduate Program in Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Justin Campagna
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Travis Panneck
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Laura Preese
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Lorene M Lanier
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| |
Collapse
|
17
|
Pro-brain-derived neurotrophic factor inhibits GABAergic neurotransmission by activating endocytosis and repression of GABAA receptors. J Neurosci 2015; 34:13516-34. [PMID: 25274828 DOI: 10.1523/jneurosci.2069-14.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
GABA is the canonical inhibitory neurotransmitter in the CNS. This inhibitory action is largely mediated by GABA type A receptors (GABAARs). Among the many factors controlling GABAergic transmission, brain-derived neurotrophic factor (BDNF) appears to play a major role in regulating synaptic inhibition. Recent findings have demonstrated that BDNF can be released as a precursor (proBDNF). Although the role of mature BDNF on GABAergic synaptogenesis and maintenance has been well studied, an important question still unanswered is whether secreted proBDNF might affect GABAergic neurotransmission. Here, we have used 14 d in vitro primary culture of hippocampal neurons and ex vivo preparations from rats to study the function of proBDNF in regulation of GABAAR trafficking and activity. We demonstrate that proBDNF impairs GABAergic transmission by the activation of two distinct pathways: (1) a RhoA-Rock-PTEN pathway that decreases the phosphorylation levels of GABAAR, thus affecting receptor function and triggering endocytosis and degradation of internalized receptors, and (2) a JAK-STAT-ICER pathway leading to the repression of GABAARs synthesis. These effects lead to the diminution of GABAergic synapses and are correlated with a decrease in GABAergic synaptic currents. These results revealed new functions for proBDNF-p75 neurotrophin receptor signaling pathway in the control of the efficacy of GABAergic synaptic activity by regulating the trafficking and synthesis of GABAARs at inhibitory synapses.
Collapse
|
18
|
Croizier S, Chometton S, Fellmann D, Risold PY. Characterization of a mammalian prosencephalic functional plan. Front Neuroanat 2015; 8:161. [PMID: 25610375 PMCID: PMC4285092 DOI: 10.3389/fnana.2014.00161] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/09/2014] [Indexed: 11/13/2022] Open
Abstract
Hypothalamic organizational concepts have greatly evolved as the primary hypothalamic pathways have been systematically investigated. In the present review, we describe how the hypothalamus arises from a molecularly heterogeneous region of the embryonic neural tube but is first differentiated as a primary neuronal cell cord (earliest mantle layer). This structure defines two axes that align onto two fundamental components: a longitudinal tractus postopticus(tpoc)/retinian component and a transverse supraoptic tract(sot)/olfactory component. We then discuss how these two axonal tracts guide the formation of all major tracts that connect the telencephalon with the hypothalamus/ventral midbrain, highlighting the existence of an early basic plan in the functional organization of the prosencephalic connectome.
Collapse
Affiliation(s)
- Sophie Croizier
- EA 3922, SFR FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté Besançon, France
| | - Sandrine Chometton
- EA 3922, SFR FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté Besançon, France
| | - Dominique Fellmann
- EA 3922, SFR FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté Besançon, France
| | - Pierre-Yves Risold
- EA 3922, SFR FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté Besançon, France
| |
Collapse
|
19
|
Nakamura Y, Darnieder LM, Deeb TZ, Moss SJ. Regulation of GABAARs by phosphorylation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 72:97-146. [PMID: 25600368 PMCID: PMC5337123 DOI: 10.1016/bs.apha.2014.11.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
γ-Aminobutyric acid type A receptors (GABAARs) are the principal mediators of fast synaptic inhibition in the brain as well as the low persistent extrasynaptic inhibition, both of which are fundamental to proper brain function. Thus unsurprisingly, deficits in GABAARs are implicated in a number of neurological disorders and diseases. The complexity of GABAAR regulation is determined not only by the heterogeneity of these receptors but also by its posttranslational modifications, the foremost, and best characterized of which is phosphorylation. This review will explore the details of this dynamic process, our understanding of which has barely scratched the surface. GABAARs are regulated by a number of kinases and phosphatases, and its phosphorylation plays an important role in governing its trafficking, expression, and interaction partners. Here, we summarize the progress in understanding the role phosphorylation plays in the regulation of GABAARs. This includes how phosphorylation can affect the allosteric modulation of GABAARs, as well as signaling pathways that affect GABAAR phosphorylation. Finally, we discuss the dysregulation of GABAAR phosphorylation and its implication in disease processes.
Collapse
|
20
|
MDMA administration during adolescence exacerbates MPTP-induced cognitive impairment and neuroinflammation in the hippocampus and prefrontal cortex. Psychopharmacology (Berl) 2014; 231:4007-18. [PMID: 24687411 DOI: 10.1007/s00213-014-3536-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 03/07/2014] [Indexed: 12/13/2022]
Abstract
RATIONALE We have recently shown that chronic exposure to 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") of adolescent mice exacerbates dopamine neurotoxicity and neuroinflammatory effects elicited by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the substantia nigra and striatum at adulthood. OBJECTIVES The present study investigated whether the amplification of MPTP effects by previous treatment with MDMA extends to the limbic and cortical regions and consequently affects cognitive performance. METHODS Mice received MDMA (10 mg/kg, twice a day/twice a week) for 9 weeks, followed by MPTP (20 mg/kg × 4 administrations), starting 2 weeks after MDMA discontinuation. Complement type 3 receptor (CD11b) and glial fibrillary acidic protein (GFAP) were evaluated by immunohistochemistry in both the hippocampus and the medial prefrontal cortex (mPFC) to measure microglia and astroglia activation. These neurochemical evaluations were paired with an assessment of cognitive performance by means of the novel object recognition (NOR) and spontaneous alternation tasks. RESULTS MPTP administration to MDMA-pretreated mice elicited a stronger activation of CD11b and GFAP in both the hippocampus and the mPFC compared with either substance administered alone. Furthermore, NOR performance was lower in MDMA-pretreated mice administered MPTP compared with mice that received either substance alone. CONCLUSIONS These results demonstrate that MDMA-MPTP negative interactions extend to the limbic and cortical regions and may result in cognitive impairment, providing further evidence that exposure to MDMA may amplify the effects of later neurotoxic insults.
Collapse
|
21
|
Lalchandani RR, Vicini S. Inhibitory collaterals in genetically identified medium spiny neurons in mouse primary corticostriatal cultures. Physiol Rep 2013; 1:e00164. [PMID: 24400165 PMCID: PMC3871478 DOI: 10.1002/phy2.164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/28/2013] [Accepted: 10/29/2013] [Indexed: 11/20/2022] Open
Abstract
Inhibitory collaterals between striatal medium spiny neuron (MSN) subtypes have been shown to critically influence striatal output. However, the low rate of inhibitory collateral detection between striatal MSNs in conventional ex vivo slice recordings has made the study of these connections challenging. Furthermore, most studies on MSN collaterals have been conducted either blind or in models, in which only one MSN subtype can be distinguished. Here, we describe a dissociated culture system using striatal and cortical neurons harvested from genetically modified mice at postnatal day 0. These mice express tdTomato and enhanced green fluorescent protein (EGFP) downstream of the dopamine D1 and D2 receptor promoters, respectively, allowing for simultaneous distinction between the two major subtypes of MSNs. In vitro, these neurons develop spines, hyperpolarized resting membrane potentials and exhibit up-and-down states, while also maintaining expression of both fluorophores through time. Using paired whole-cell patch-clamp recordings from identified MSNs at 14 days in vitro, we are able to detect a much higher rate of inhibitory functional synapses than what has been previously reported in slice recordings. These collateral synapses release γ-Aminobutyric acid (GABA) and shape the firing patters of other MSNs. Although reduced in vitro models have a number of inherent limitations, the cultures described here provide a unique opportunity to study frequently observed functional collaterals between identifiable MSNs. Additionally, cultured neurons allow for control of the extracellular environment, with the potential to investigate pharmacological regulation of inhibitory MSNs collaterals.
Collapse
Affiliation(s)
- Rupa R Lalchandani
- Graduate Program in Physiology and Biophysics, Georgetown University Washington, District of Columbia, 20007 ; Department of Pharmacology and Physiology, Georgetown University Washington, District of Columbia, 20007
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University Washington, District of Columbia, 20007
| |
Collapse
|
22
|
Dopamine D2 receptors regulate collateral inhibition between striatal medium spiny neurons. J Neurosci 2013; 33:14075-86. [PMID: 23986243 DOI: 10.1523/jneurosci.0692-13.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The principle neurons of the striatum are GABAergic medium spiny neurons (MSNs), whose collateral synapses onto neighboring neurons play critical roles in striatal function. MSNs can be divided by dopamine receptor expression into D1-class and D2-class MSNs, and alterations in D2 MSNs are associated with various pathological states. Despite overwhelming evidence for D2 receptors (D2Rs) in maintaining proper striatal function, it remains unclear how MSN collaterals are specifically altered by D2R activation. Here, we report that chronic D2R stimulation regulates MSN collaterals in vitro by presynaptic and postsynaptic mechanisms. We used corticostriatal cultures from mice in which MSN subtypes were distinguished by fluorophore expression. Quinpirole, an agonist for D2/3 receptors, was used to chronically activate D2Rs. Quinpirole increased the rate and strength of collateral formation onto D2R-containing MSNs as measured by dual whole-cell patch-clamp recordings. Additionally, these neurons were more sensitive to low concentrations of GABA and exhibited an increase in gephyrin puncta density, suggesting increased postsynaptic GABAA receptors. Last, quinpirole treatment increased presynaptic GABA release sites, as shown by increased frequency of sIPSCs and mIPSCs, correlating with increased VGAT (vesicular GABA transporter) puncta. Combined with the observation that there were no detectable differences in sensitivity to specific GABAA receptor modulators, we provide evidence that D2R activation powerfully transforms MSN collaterals via coordinated presynaptic and postsynaptic alterations. As the D2 class of MSNs is highly implicated in Parkinson's disease and other neurological disorders, our findings may contribute to understanding and treating the changes that occur in these pathological states.
Collapse
|
23
|
Fuchs C, Abitbol K, Burden JJ, Mercer A, Brown L, Iball J, Anne Stephenson F, Thomson AM, Jovanovic JN. GABA(A) receptors can initiate the formation of functional inhibitory GABAergic synapses. Eur J Neurosci 2013; 38:3146-58. [PMID: 23909897 PMCID: PMC4028986 DOI: 10.1111/ejn.12331] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 01/16/2023]
Abstract
The mechanisms that underlie the selection of an inhibitory GABAergic axon's postsynaptic targets and the formation of the first contacts are currently unknown. To determine whether expression of GABAA receptors (GABAA Rs) themselves--the essential functional postsynaptic components of GABAergic synapses--can be sufficient to initiate formation of synaptic contacts, a novel co-culture system was devised. In this system, the presynaptic GABAergic axons originated from embryonic rat basal ganglia medium spiny neurones, whereas their most prevalent postsynaptic targets, i.e., α1/β2/γ2-GABAA Rs, were expressed constitutively in a stably transfected human embryonic kidney 293 (HEK293) cell line. The first synapse-like contacts in these co-cultures were detected by colocalization of presynaptic and postsynaptic markers within 2 h. The number of contacts reached a plateau at 24 h. These contacts were stable, as assessed by live cell imaging; they were active, as determined by uptake of a fluorescently labelled synaptotagmin vesicle-luminal domain-specific antibody; and they supported spontaneous and action potential-driven postsynaptic GABAergic currents. Ultrastructural analysis confirmed the presence of characteristics typical of active synapses. Synapse formation was not observed with control or N-methyl-d-aspartate receptor-expressing HEK293 cells. A prominent increase in synapse formation and strength was observed when neuroligin-2 was co-expressed with GABAA Rs, suggesting a cooperative relationship between these proteins. Thus, in addition to fulfilling an essential functional role, postsynaptic GABAA Rs can promote the adhesion of inhibitory axons and the development of functional synapses.
Collapse
Affiliation(s)
- Celine Fuchs
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Karine Abitbol
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jemima J Burden
- MRC Laboratory of Molecular Cell Biology, University College LondonLondon, UK
| | - Audrey Mercer
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Laura Brown
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jonathan Iball
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - F Anne Stephenson
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Alex M Thomson
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jasmina N Jovanovic
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| |
Collapse
|
24
|
Costa G, Frau L, Wardas J, Pinna A, Plumitallo A, Morelli M. MPTP-induced dopamine neuron degeneration and glia activation is potentiated in MDMA-pretreated mice. Mov Disord 2013; 28:1957-65. [PMID: 24108425 DOI: 10.1002/mds.25646] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/08/2013] [Accepted: 07/23/2013] [Indexed: 12/13/2022] Open
Abstract
Clinical observations report a greater propensity to develop Parkinson's disease (PD) in amphetamine users. 3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is an amphetamine-related drug that is largely consumed by adolescents and young adults, which may have neuroinflammatory and neurotoxic effects. Here, the objective was to evaluate in mice whether consumption of MDMA during adolescence might influence the neuroinflammatory and neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a toxin known to induce PD in humans. The activation of astroglia and microglia by glial fibrillary acidic protein (GFAP) and complement receptor type 3 (CD11b) immunohistochemistry and the degeneration of dopaminergic neurons by tyrosine hydroxylase (TH) immunohistochemistry were evaluated. MPTP (20 mg/kg × 4) was administered to mice treated from ages 8 weeks to 17 weeks with MDMA (10 mg/kg twice daily, two times a week). In mice that were chronically treated with MDMA, administration of MPTP induced a higher microglial and astroglial response in both the striatum and the substantia nigra pars compacta (SNc) compared with vehicle-treated or vehicle + MPTP-treated mice. Inflammatory changes were associated with a decrease in TH immunoreactivity in the SNc of MDMA-treated mice and with a further decrease in the striatum and the SNc of MDMA + MPTP-treated mice compared with vehicle-treated, MDMA-treated, and MPTP-treated mice. The results demonstrate that chronic administration of MDMA during late adolescence in mice exacerbates the neurodegeneration and neuroinflammation caused by MPTP, suggesting that MDMA may constitute a risk factor for dopaminergic neuron degeneration.
Collapse
Affiliation(s)
- Giulia Costa
- Department of Biomedical Sciences, Section of Neuropsychopharmacology, University of Cagliari, Cagliari, Italy
| | | | | | | | | | | |
Collapse
|
25
|
Katow H, Abe K, Katow T, Zamani A, Abe H. Development of the GABA-ergic signaling system and its role in larval swimming in sea urchin. ACTA ACUST UNITED AC 2013; 216:1704-16. [PMID: 23307803 DOI: 10.1242/jeb.074856] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study aimed to elucidate the development and γ-amino butyric acid (GABA)-ergic regulation of larval swimming in the sea urchin Hemicentrotus pulcherrimus by cloning glutamate decarboxylase (Hp-gad), GABAA receptor (Hp-gabrA) and GABAA receptor-associated protein (Hp-gabarap), and by performing immunohistochemistry. The regulation of larval swimming was increasingly dependent on the GABAergic system, which was active from the 2 days post-fertilization (d.p.f.) pluteus stage onwards. GABA-immunoreactive cells were detected as a subpopulation of secondary mesenchyme cells during gastrulation and eventually constituted the ciliary band and a subpopulation of blastocoelar cells during the pluteus stage. Hp-gad transcription was detected by RT-PCR during the period when Hp-Gad-positive cells were seen as a subpopulation of blastocoelar cells and on the apical side of the ciliary band from the 2 d.p.f. pluteus stage. Consistent with these observations, inhibition of GAD with 3-mercaptopropioninc acid inhibited GABA immunoreactivity and larval swimming dose dependently. Hp-gabrA amplimers were detected weakly in unfertilized eggs and 4 d.p.f. plutei but strongly from fertilized eggs to 2 d.p.f. plutei, and Hp-GabrA, together with GABA, was localized at the ciliary band in association with dopamine receptor D1 from the two-arm pluteus stage. Hp-gabarap transcription and protein expression were detected from the swimming blastula stage. Inhibition of the GABAA receptor by bicuculline inhibited larval swimming dose dependently. Inhibition of larval swimming by either 3-mercaptopropionic acid or bicuculline was more severe in older larvae (17 and 34 d.p.f. plutei) than in younger ones (1 d.p.f. prism larvae).
Collapse
Affiliation(s)
- Hideki Katow
- Research Center for Marine Biology, Tohoku University, Asamushi, Aomori, Aomori 039-3501, Japan.
| | | | | | | | | |
Collapse
|
26
|
Fasano C, Bourque MJ, Lapointe G, Leo D, Thibault D, Haber M, Kortleven C, Desgroseillers L, Murai KK, Trudeau LÉ. Dopamine facilitates dendritic spine formation by cultured striatal medium spiny neurons through both D1 and D2 dopamine receptors. Neuropharmacology 2012; 67:432-43. [PMID: 23231809 DOI: 10.1016/j.neuropharm.2012.11.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 11/23/2012] [Accepted: 11/26/2012] [Indexed: 01/01/2023]
Abstract
Variations of dopamine (DA) levels induced by drugs of abuse or in the context of Parkinson's disease modulate the number of dendritic spines in medium spiny neurons (MSNs) of the striatum, showing that DA plays a major role in the structural plasticity of MSNs. However, little is presently known regarding early spine development in MSNs occurring before the arrival of cortical inputs and in particular about the role of DA and D1 (D1R) and D2 (D2R) DA receptors. A cell culture model reconstituting early cellular interactions between MSNs, intrinsic cholinergic interneurons and DA neurons was used to study the role of DA in spine formation. After 5 or 10 days in vitro, the presence of DA neurons increased the number of immature spine-like protrusions. In MSN monocultures, chronic activation of D1R or D2R also increased the number of spines and spinophilin expression in MSNs, suggesting a direct role for these receptors. In DA-MSN cocultures, chronic blockade of D1R or D2R reduced the number of dendritic spines. Interestingly, the combined activation or blockade of both D1R and D2R failed to elicit more extensive spine formation, suggesting that both receptors act through a mechanism that is not additive. Finally, we found increased ionotropic glutamate receptor responsiveness and miniature excitatory postsynaptic current (EPSC) frequency in DA-MSN co-cultures, in parallel with a higher number of spines containing PSD-95, suggesting that the newly formed spines present functional post-synaptic machinery preparing the MSNs to receive additional glutamatergic contacts. These results represent a first step in the understanding of how dopamine neurons promote the structural plasticity of MSNs during the development of basal ganglia circuits.
Collapse
Affiliation(s)
- Caroline Fasano
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Ferrari DC, Mdzomba BJ, Dehorter N, Lopez C, Michel FJ, Libersat F, Hammond C. Midbrain dopaminergic neurons generate calcium and sodium currents and release dopamine in the striatum of pups. Front Cell Neurosci 2012; 6:7. [PMID: 22408606 PMCID: PMC3297358 DOI: 10.3389/fncel.2012.00007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/11/2012] [Indexed: 12/17/2022] Open
Abstract
Midbrain dopaminergic neurons (mDA neurons) are essential for the control of diverse motor and cognitive behaviors. However, our understanding of the activity of immature mDA neurons is rudimentary. Rodent mDA neurons migrate and differentiate early in embryonic life and dopaminergic axons enter the striatum and contact striatal neurons a few days before birth, but when these are functional is not known. Here, we recorded Ca2+ transients and Na+ spikes from embryonic (E16–E18) and early postnatal (P0–P7) mDA neurons with dynamic two-photon imaging and patch clamp techniques in slices from tyrosine hydroxylase-GFP mice, and measured evoked dopamine release in the striatum with amperometry. We show that half of identified E16–P0 mDA neurons spontaneously generate non-synaptic, intrinsically driven Ca2+ spikes and Ca2+ plateaus mediated by N- and L-type voltage-gated Ca2+ channels. Starting from E18–P0, half of the mDA neurons also reliably generate overshooting Na+ spikes with an abrupt maturation at birth (P0 = E19). At that stage (E18–P0), dopaminergic terminals release dopamine in a calcium-dependent manner in the striatum in response to local stimulation. This suggests that mouse striatal dopaminergic synapses are functional at birth.
Collapse
Affiliation(s)
- Diana C Ferrari
- Institut National de la Recherche Médicale et de la Santé Inserm, INMED UMR 901 Marseille, France
| | | | | | | | | | | | | |
Collapse
|
28
|
Rett syndrome mutation MeCP2 T158A disrupts DNA binding, protein stability and ERP responses. Nat Neurosci 2011; 15:274-83. [PMID: 22119903 PMCID: PMC3267879 DOI: 10.1038/nn.2997] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 10/28/2011] [Indexed: 11/08/2022]
Abstract
Mutations in the MECP2 gene cause the autism spectrum disorder Rett Syndrome (RTT). One of the most common mutations associated with RTT occurs at MeCP2 Threonine 158 converting it to Methionine (T158M) or Alanine (T158A). To understand the role of T158 mutation in the pathogenesis of RTT, we generated knockin mice recapitulating MeCP2 T158A mutation. Here we show a causal role for T158A mutation in the development of RTT-like phenotypes including developmental regression, motor dysfunction, and learning and memory deficits. These phenotypes resemble those in Mecp2-null mice and manifest through a reduction in MeCP2 binding to methylated DNA and a decrease in MeCP2 protein stability. Importantly, the age-dependent development of event-related neuronal responses are disrupted by MeCP2 mutation, suggesting that impaired neuronal circuitry underlies the pathogenesis of RTT and that assessment of event-related potentials may serve as a biomarker for RTT and treatment evaluation.
Collapse
|
29
|
Dehorter N, Michel FJ, Marissal T, Rotrou Y, Matrot B, Lopez C, Humphries MD, Hammond C. Onset of Pup Locomotion Coincides with Loss of NR2C/D-Mediated Cortico-Striatal EPSCs and Dampening of Striatal Network Immature Activity. Front Cell Neurosci 2011; 5:24. [PMID: 22125512 PMCID: PMC3221398 DOI: 10.3389/fncel.2011.00024] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/21/2011] [Indexed: 11/13/2022] Open
Abstract
Adult motor coordination requires strong coincident cortical excitatory input to hyperpolarized medium spiny neurons (MSNs), the dominant neuronal population of the striatum. However, cortical and subcortical neurons generate during development large ongoing patterns required for activity-dependent construction of networks. This raises the question of whether immature MSNs have adult features from early stages or whether they generate immature patterns that are timely silenced to enable locomotion. Using a wide range of techniques including dynamic two-photon imaging, whole cell or single-channel patch clamp recording in slices from Nkx2.1-GFP mice, we now report a silencing of MSNs that timely coincides with locomotion. At embryonic stage (as early as E16) and during early postnatal days, genetically identified MSNs have a depolarized resting membrane potential, a high input resistance and lack both inward rectifying (IKIR) and early slowly inactivating (ID) potassium currents. They generate intrinsic voltage-gated clustered calcium activity without synaptic components. From postnatal days 5–7, the striatal network transiently generates synapse-driven giant depolarizing potentials when activation of cortical inputs evokes long lasting EPSCs in MSNs. Both are mediated by NR2C/D-receptors. These immature features are abruptly replaced by adult ones before P10: MSNs express IKIR and ID and generate short lasting, time-locked cortico-striatal AMPA/NMDA EPSCs with no NR2C/D component. This shift parallels the onset of quadruped motion by the pup. Therefore, MSNs generate immature patterns that are timely shut off to enable the coordination of motor programs.
Collapse
|
30
|
Morales P, Bustamante D, Espina-Marchant P, Neira-Peña T, Gutiérrez-Hernández MA, Allende-Castro C, Rojas-Mancilla E. Pathophysiology of perinatal asphyxia: can we predict and improve individual outcomes? EPMA J 2011. [PMID: 23199150 PMCID: PMC3405380 DOI: 10.1007/s13167-011-0100-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Perinatal asphyxia occurs still with great incidence whenever delivery is prolonged, despite improvements in perinatal care. After asphyxia, infants can suffer from short- to long-term neurological sequelae, their severity depend upon the extent of the insult, the metabolic imbalance during the re-oxygenation period and the developmental state of the affected regions. Significant progresses in understanding of perinatal asphyxia pathophysiology have achieved. However, predictive diagnostics and personalised therapeutic interventions are still under initial development. Now the emphasis is on early non-invasive diagnosis approach, as well as, in identifying new therapeutic targets to improve individual outcomes. In this review we discuss (i) specific biomarkers for early prediction of perinatal asphyxia outcome; (ii) short and long term sequelae; (iii) neurocircuitries involved; (iv) molecular pathways; (v) neuroinflammation systems; (vi) endogenous brain rescue systems, including activation of sentinel proteins and neurogenesis; and (vii) therapeutic targets for preventing or mitigating the effects produced by asphyxia.
Collapse
Affiliation(s)
- Paola Morales
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Diego Bustamante
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Pablo Espina-Marchant
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Tanya Neira-Peña
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Manuel A. Gutiérrez-Hernández
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Camilo Allende-Castro
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Edgardo Rojas-Mancilla
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| |
Collapse
|
31
|
Shrivastava AN, Triller A, Sieghart W. GABA(A) Receptors: Post-Synaptic Co-Localization and Cross-Talk with Other Receptors. Front Cell Neurosci 2011; 5:7. [PMID: 21734865 PMCID: PMC3123775 DOI: 10.3389/fncel.2011.00007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 06/06/2011] [Indexed: 11/14/2022] Open
Abstract
γ-Aminobutyric acid type A receptors (GABAARs) are the major inhibitory neurotransmitter receptors in the central nervous system, and importantly contribute to the functional regulation of the nervous system. Several studies in the last few decades have convincingly shown that GABA can be co-localized with other neurotransmitters in the same synapse, and can be co-released with these neurotransmitters either from the same vesicles or from different vesicle pools. The co-released transmitters may act on post-synaptically co-localized receptors resulting in a simultaneous activation of both receptors. Most of the studies investigating such co-activation observed a reduced efficacy of GABA for activating GABAARs and thus, a reduced inhibition of the post-synaptic neuron. Similarly, in several cases activation of GABAARs has been reported to suppress the response of the associated receptors. Such a receptor cross-talk is either mediated via a direct coupling between the two receptors or via the activation of intracellular signaling pathways and is used for fine tuning of inhibition in the nervous system. Recently, it was demonstrated that a direct interaction of different receptors might already occur in intracellular compartments and might also be used to specifically target the receptors to the cell membrane. In this article, we provide an overview on such cross-talks between GABAARs and several other neurotransmitter receptors and briefly discuss their possible physiological and clinical importance.
Collapse
Affiliation(s)
- Amulya Nidhi Shrivastava
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University of Vienna Vienna, Austria
| | | | | |
Collapse
|
32
|
Lin HC, Tseng YC, Mao SC, Chen PS, Gean PW. GABAA receptor endocytosis in the basolateral amygdala is critical to the reinstatement of fear memory measured by fear-potentiated startle. J Neurosci 2011; 31:8851-61. [PMID: 21677169 PMCID: PMC6622947 DOI: 10.1523/jneurosci.0979-11.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/01/2011] [Accepted: 05/01/2011] [Indexed: 11/21/2022] Open
Abstract
Reinstatement represents a phenomenon that may be used to model the effects of retraumatization observed in patients with posttraumatic stress disorder (PTSD). In this study, we found intraperitoneal injection of the β-adrenergic receptor antagonist propranolol (10 mg/kg) 1 h before reinstatement training attenuated reinstatement of fear memory in rats. Conversely, reinstatement was facilitated by intra-amygdalar administration of β-adrenergic receptor agonist isoproterenol (Iso; 2 μg per side) 30 min before reinstatement training. The frequency and amplitude of the miniature IPSC (mIPSC) and the surface expression of the β3 and γ2 subunits of the GABA(A) receptor (GABA(A)R) were significantly lower in reinstated than in extinction rats, whereas the AMPA/NMDA ratio and the surface expression of GluR1 and GluR2 in the amygdala did not differ between groups. In amygdala slices, Iso-induced decrease in the surface β3 subunit of GABA(A) receptor was blocked by a Tat-conjugated dynamin function-blocking peptide (Tat-P4) pretreatment (10 μm for 30 min). By contrast, Tat-scramble peptide had no effect. Intravenous injection (3 μmol/kg) or intra-amygdalar infusion (30 pmol per side) of Tat-P4 interfered with reinstatement. Reinstatement increased the association between protein phosphatase 2A (PP2A) and the β3 subunit of the GABA(A)R, which was abolished by PP1/PP2A inhibitors okadaic acid and calyculin A. These results suggest the involvement of β-adrenergic receptor activation and GABA(A) receptor endocytosis in the amygdala for the reinstatement in fear memory.
Collapse
Affiliation(s)
- Hui-Ching Lin
- Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan 701
| | - Yu-Chou Tseng
- Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan 701
| | - Sheng-Chun Mao
- Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan 701
| | - Po-See Chen
- Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan 701
| | - Po-Wu Gean
- Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan 701
| |
Collapse
|
33
|
Porcher C, Hatchett C, Longbottom RE, McAinch K, Sihra TS, Moss SJ, Thomson AM, Jovanovic JN. Positive feedback regulation between gamma-aminobutyric acid type A (GABA(A)) receptor signaling and brain-derived neurotrophic factor (BDNF) release in developing neurons. J Biol Chem 2011; 286:21667-77. [PMID: 21474450 DOI: 10.1074/jbc.m110.201582] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
During the early development of the nervous system, γ-aminobutyric acid (GABA) type A receptor (GABA(A)R)-mediated signaling parallels the neurotrophin/tropomyosin-related kinase (Trk)-dependent signaling in controlling a number of processes from cell proliferation and migration, via dendritic and axonal outgrowth, to synapse formation and plasticity. Here we present the first evidence that these two signaling systems regulate each other through a complex positive feedback mechanism. We first demonstrate that GABA(A)R activation leads to an increase in the cell surface expression of these receptors in cultured embryonic cerebrocortical neurons, specifically at the stage when this activity causes depolarization of the plasma membrane and Ca(2+) influx through L-type voltage-gated Ca(2+) channels. We further demonstrate that GABA(A)R activity triggers release of the brain-derived neurotrophic factor (BDNF), which, in turn by activating TrkB receptors, mediates the observed increase in cell surface expression of GABA(A)Rs. This BDNF/TrkB-dependent increase in surface levels of GABA(A)Rs requires the activity of phosphoinositide 3-kinase (PI3K) and protein kinase C (PKC) and does not involve the extracellular signal-regulated kinase (ERK) 1/2 activity. The increase in GABA(A)R surface levels occurs due to an inhibition of the receptor endocytosis by BDNF, whereas the receptor reinsertion into the plasma membrane remains unaltered. Thus, GABA(A)R activity is a potent regulator of the BDNF release during neuronal development, and at the same time, it is strongly enhanced by the activity of the BDNF/TrkB/PI3K/PKC signaling pathway.
Collapse
Affiliation(s)
- Christophe Porcher
- Institut de Neurobiologie de la Méditerranée, INSERM Unité 901 and Université de La Méditerranée, 13273 Marseille Cedex 09, France
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Smith KR, Kittler JT. The cell biology of synaptic inhibition in health and disease. Curr Opin Neurobiol 2010; 20:550-6. [PMID: 20650630 DOI: 10.1016/j.conb.2010.06.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/08/2010] [Accepted: 06/10/2010] [Indexed: 11/24/2022]
Abstract
Fast synaptic inhibition is largely mediated by GABA(A) receptors (GABA(A)Rs), ligand-gated chloride channels that play an essential role in the control of cell and network activity in the brain. Recent work has demonstrated that the delivery, number and stability of GABA(A)Rs at inhibitory synapses play a key role in the dynamic regulation of inhibitory synaptic efficacy and plasticity. The regulatory pathways essential for the fine-tuning of synaptic inhibition have also emerged as key sites of vulnerability during pathological changes in cell excitability in disease states.
Collapse
Affiliation(s)
- Katharine R Smith
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | | |
Collapse
|