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Ando H, Shimizu-Okabe C, Okura N, Yafuso T, Kosaka Y, Kobayashi S, Okabe A, Takayama C. Reduced gene expression of KCC2 accelerates axonal regeneration and reduces motor dysfunctions after tibial nerve severance and suturing. Neuroscience 2024:S0306-4522(24)00212-4. [PMID: 38788828 DOI: 10.1016/j.neuroscience.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/09/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024]
Abstract
Gamma-aminobutyric acid and glycine (GABA/Gly) are predominantly inhibitory neurotransmitters in the mature central nervous system; however, they mediate membrane potential depolarization during development. These differences in actions depend on intracellular Cl- concentrations ([Cl-]i), which are primarily regulated by potassium chloride cotransporter 2 (KCC2). After nerve injury, KCC2 expression markedly decreases and GABA/Gly mediate depolarization. Following nerve regeneration, KCC2 expression recovers and GABA/Gly become inhibitory, suggesting that KCC2 reduction and GABA/Gly excitation may be crucial for axonal regeneration. To directly clarify their involvement in regeneration, we analyzed recovery processes after tibial nerve severance and suturing between heterozygous KCC2 knockout mice (HT), whose KCC2 levels are halved, and their wild-type littermates (WT). Compared with WT mice, the sciatic functional index-indicating lower limb motor function-was significantly higher until 28 days after operation (D28) in HT mice. Furthermore, at D7, many neurofilament-positive fibers were elongated into the distal part of the ligated nerve in HT mice only, and myelinated axonal density was significantly higher at D21 and D28 in HT animals. Electron microscopy and galanin immunohistochemistry indicated a shorter nerve degeneration period in HT mice. Moreover, a less severe decrease in choline acetyltransferase was observed in HT mice. These results suggest that nerve degeneration and regeneration proceed more rapidly in HT mice, resulting in milder motor dysfunction. Via similar microglial activation, nerve surgery may reduce KCC2 levels more rapidly in HT mice, followed by earlier increased [Cl-]i and longer-lasting GABA/Gly excitation. Taken together, reduced KCC2 may accelerate nerve regeneration via GABA/Gly excitation.
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Affiliation(s)
- Hironobu Ando
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Chigusa Shimizu-Okabe
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Nobuhiko Okura
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Tsukasa Yafuso
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Yoshinori Kosaka
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Shiori Kobayashi
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan
| | - Akihito Okabe
- Department of Nutritional Science, Faculty of Health and Welfare, Seinan Jo Gakuin University, Fukuoka 803-0835, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa, 9030215, Japan.
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2
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Järvelä V, Hamze M, Komulainen-Ebrahim J, Rahikkala E, Piispala J, Kallio M, Kangas SM, Nickl T, Huttula M, Hinttala R, Uusimaa J, Medina I, Immonen EV. A novel pathogenic SLC12A5 missense variant in epilepsy of infancy with migrating focal seizures causes impaired KCC2 chloride extrusion. Front Mol Neurosci 2024; 17:1372662. [PMID: 38660387 PMCID: PMC11039960 DOI: 10.3389/fnmol.2024.1372662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/19/2024] [Indexed: 04/26/2024] Open
Abstract
The potassium-chloride co-transporter 2, KCC2, is a neuron-specific ion transporter that plays a multifunctional role in neuronal development. In mature neurons, KCC2 maintains a low enough intracellular chloride concentration essential for inhibitory neurotransmission. During recent years, pathogenic variants in the KCC2 encoding gene SLC12A5 affecting the functionality or expression of the transporter protein have been described in several patients with epilepsy of infancy with migrating focal seizures (EIMFS), a devastating early-onset developmental and epileptic encephalopathy. In this study, we identified a novel recessively inherited SLC12A5 c.692G>A, p. (R231H) variant in a patient diagnosed with severe and drug-resistant EIMFS and profound intellectual disability. The functionality of the variant was assessed in vitro by means of gramicidin-perforated patch-clamp experiments and ammonium flux assay, both of which indicated a significant reduction in chloride extrusion. Based on surface immunolabeling, the variant showed a reduction in membrane expression. These findings implicate pathogenicity of the SLC12A5 variant that leads to impaired inhibitory neurotransmission, increasing probability for hyperexcitability and epileptogenesis.
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Affiliation(s)
- Viivi Järvelä
- Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Mira Hamze
- INMED, INSERM, Aix-Marseille University, Marseille, France
| | - Jonna Komulainen-Ebrahim
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Elisa Rahikkala
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Department of Clinical Genetics, Oulu University Hospital, Oulu, Finland
| | - Johanna Piispala
- Department of Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Mika Kallio
- Department of Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Salla M. Kangas
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Tereza Nickl
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Laboratory of Transgenic Models of Diseases, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Marko Huttula
- Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
| | - Reetta Hinttala
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Johanna Uusimaa
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Igor Medina
- INMED, INSERM, Aix-Marseille University, Marseille, France
| | - Esa-Ville Immonen
- Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
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3
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Pushkin AN, Kay Y, Herring BE. Protein 4.1N Plays a Cell Type-Specific Role in Hippocampal Glutamatergic Synapse Regulation. J Neurosci 2023; 43:8336-8347. [PMID: 37845032 PMCID: PMC10711697 DOI: 10.1523/jneurosci.0185-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 09/14/2023] [Accepted: 10/02/2023] [Indexed: 10/18/2023] Open
Abstract
Many glutamatergic synapse proteins contain a 4.1N protein binding domain. However, a role for 4.1N in the regulation of glutamatergic neurotransmission has been controversial. Here, we observe significantly higher expression of protein 4.1N in granule neurons of the dentate gyrus (DG granule neurons) compared with other hippocampal regions. We discover that reducing 4.1N expression in rat DG granule neurons of either sex results in a significant reduction in glutamatergic synapse function that is caused by a decrease in the number of glutamatergic synapses. By contrast, we find reduction of 4.1N expression in hippocampal CA1 pyramidal neurons has no impact on basal glutamatergic neurotransmission. We also find 4.1N's C-terminal domain (CTD) to be nonessential to its role in the regulation of glutamatergic synapses of DG granule neurons. Instead, we show that 4.1N's four-point-one, ezrin, radixin, and moesin (FERM) domain is essential for supporting synaptic AMPA receptor (AMPAR) function in these neurons. Altogether, this work demonstrates a novel, cell type-specific role for protein 4.1N in governing glutamatergic synapse function.SIGNIFICANCE STATEMENT Glutamatergic synapses exhibit immense molecular diversity. In comparison to heavily studied Schaffer collateral, CA1 glutamatergic synapses, significantly less is known about perforant path-dentate gyrus (DG) synapses. Our data demonstrate that compromising 4.1N function in CA1 pyramidal neurons produces no alteration in basal glutamatergic synaptic transmission. However, in DG granule neurons, compromising 4.1N function leads to a significant decrease in the strength of glutamatergic neurotransmission at perforant pathway synapses. Together, our data identifies 4.1N as a cell type-specific regulator of synaptic transmission within the hippocampus and reveals a unique molecular program that governs perforant pathway synapse function.
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Affiliation(s)
- Anna N Pushkin
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089
| | - Yuni Kay
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089
| | - Bruce E Herring
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089
- Department of Biological Sciences, Neurobiology Section, Dornslife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, California 90089
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4
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Abstract
Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in the methyl-CpG binding protein-2 (MeCP2) gene that is characterized by epilepsy, intellectual disability, autistic features, speech deficits, and sleep and breathing abnormalities. Neurologically, patients with all three disorders display microcephaly, aberrant dendritic morphology, reduced spine density, and an imbalance of excitatory/inhibitory signaling. Loss-of-function mutations in the cyclin-dependent kinase-like 5 (CDKL5) and FOXG1 genes also cause similar behavioral and neurobiological defects and were referred to as congenital or variant Rett syndrome. The relatively recent realization that CDKL5 deficiency disorder (CDD), FOXG1 syndrome, and Rett syndrome are distinct neurodevelopmental disorders with some distinctive features have resulted in separate focus being placed on each disorder with the assumption that distinct molecular mechanisms underlie their pathogenesis. However, given that many of the core symptoms and neurological features are shared, it is likely that the disorders share some critical molecular underpinnings. This review discusses the possibility that deregulation of common molecules in neurons and astrocytes plays a central role in key behavioral and neurological abnormalities in all three disorders. These include KCC2, a chloride transporter, vGlut1, a vesicular glutamate transporter, GluD1, an orphan-glutamate receptor subunit, and PSD-95, a postsynaptic scaffolding protein. We propose that reduced expression or activity of KCC2, vGlut1, PSD-95, and AKT, along with increased expression of GluD1, is involved in the excitatory/inhibitory that represents a key aspect in all three disorders. In addition, astrocyte-derived brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), and inflammatory cytokines likely affect the expression and functioning of these molecules resulting in disease-associated abnormalities.
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Affiliation(s)
- Santosh R D’Mello
- Department of Biological Sciences, Louisiana State University Shreveport, Shreveport, LA 71104, USA
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5
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Pethe A, Hamze M, Giannaki M, Heimrich B, Medina I, Hartmann AM, Roussa E. K +/Cl - cotransporter 2 (KCC2) and Na +/ HCO3- cotransporter 1 (NBCe1) interaction modulates profile of KCC2 phosphorylation. Front Cell Neurosci 2023; 17:1253424. [PMID: 37881493 PMCID: PMC10595033 DOI: 10.3389/fncel.2023.1253424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/07/2023] [Indexed: 10/27/2023] Open
Abstract
K+/Cl- cotransporter 2 (KCC2) is a major Cl- extruder in mature neurons and is responsible for the establishment of low intracellular [Cl-], necessary for fast hyperpolarizing GABAA-receptor mediated synaptic inhibition. Electrogenic sodium bicarbonate cotransporter 1 (NBCe1) is a pH regulatory protein expressed in neurons and glial cells. An interactome study identified NBCe1 as a possible interaction partner of KCC2. In this study, we investigated the putative effect of KCC2/NBCe1 interaction in baseline and the stimulus-induced phosphorylation pattern and function of KCC2. Primary mouse hippocampal neuronal cultures from wildtype (WT) and Nbce1-deficient mice, as well as HEK-293 cells stably transfected with KCC2WT, were used. The results show that KCC2 and NBCe1 are interaction partners in the mouse brain. In HEKKCC2 cells, pharmacological inhibition of NBCs with S0859 prevented staurosporine- and 4-aminopyridine (4AP)-induced KCC2 activation. In mature cultures of hippocampal neurons, however, S0859 completely inhibited postsynaptic GABAAR and, thus, could not be used as a tool to investigate the role of NBCs in GABA-dependent neuronal networks. In Nbce1-deficient immature hippocampal neurons, baseline phosphorylation of KCC2 at S940 was downregulated, compared to WT, and exposure to staurosporine failed to reduce pKCC2 S940 and T1007. In Nbce1-deficient mature neurons, baseline levels of pKCC2 S940 and T1007 were upregulated compared to WT, whereas after 4AP treatment, pKCC2 S940 was downregulated, and pKCC2 T1007 was further upregulated. Functional experiments showed that the levels of GABAAR reversal potential, baseline intracellular [Cl-], Cl- extrusion, and baseline intracellular pH were similar between WT and Nbce1-deficient neurons. Altogether, our data provide a primary description of the properties of KCC2/NBCe1 protein-protein interaction and implicate modulation of stimulus-mediated phosphorylation of KCC2 by NBCe1/KCC2 interaction-a mechanism with putative pathophysiological relevance.
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Affiliation(s)
- Abhishek Pethe
- Department of Molecular Embryology, Faculty of Medicine, Institute for Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Mira Hamze
- INMED, INSERM, Aix-Marseille University, Marseille, France
| | - Marina Giannaki
- Department of Molecular Embryology, Faculty of Medicine, Institute for Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Bernd Heimrich
- Department of Neuroanatomy, Faculty of Medicine, Institute for Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Igor Medina
- INMED, INSERM, Aix-Marseille University, Marseille, France
| | - Anna-Maria Hartmann
- Division of Neurogenetics, Faculty VI, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine, Institute for Anatomy and Cell Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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6
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Pol E, Côme E, Merlaud Z, Gouhier J, Russeau M, Scotto-Lomassese S, Moutkine I, Marques X, Lévi S. NKCC1 and KCC2 Chloride Transporters Have Different Membrane Dynamics on the Surface of Hippocampal Neurons. Cells 2023; 12:2363. [PMID: 37830575 PMCID: PMC10571912 DOI: 10.3390/cells12192363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/12/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
Na-K-2Cl cotransporter 1 (NKCC1) regulates chloride influx in neurons and thereby GABAA receptor activity in normal and pathological conditions. Here, we characterized in hippocampal neurons the membrane expression, distribution and dynamics of exogenous NKCC1a and NKCC1b isoforms and compared them to those of the chloride extruder K-Cl cotransporter 2 (KCC2). We found that NKCC1a and NKCC1b behave quite similarly. NKCC1a/1b but not KCC2 are present along the axon initial segment where they are confined. Moreover, NKCC1a/1b are detected in the somato-dendritic compartment at a lower level than KCC2, where they form fewer, smaller and less compact clusters at perisynaptic and extrasynaptic sites. Interestingly, ~60% of dendritic clusters of NKCC1a/1b are colocalized with KCC2. They are larger and brighter than those devoid of KCC2, suggesting a particular NKCC1a/1b-KCC2 relationship. In agreement with the reduced dendritic clustering of NKCC1a/1b compared with that of KCC2, NKCC1a/1b are more mobile on the dendrite than KCC2, suggesting weaker cytoskeletal interaction. NKCC1a/b are confined to endocytic zones, where they spend more time than KCC2. However, they spend less time in these compartments than at the synapses, suggesting that they can rapidly leave endocytic zones to increase the membrane pool, which can happen in pathological conditions. Thus, NKCC1a/b have different membrane dynamics and clustering from KCC2, which helps to explain their low level in the neuronal membrane, while allowing a rapid increase in the membrane pool under pathological conditions.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Sabine Lévi
- Institut du Fer à Moulin, Institut National de la Santé Et de la Recherche Médicale (INSERM) UMR-S 1270, Sorbonne Université, 75005 Paris, France; (E.P.); (E.C.); (Z.M.); (J.G.); (M.R.); (S.S.-L.); (I.M.); (X.M.)
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7
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Byvaltcev E, Behbood M, Schleimer JH, Gensch T, Semyanov A, Schreiber S, Strauss U. KCC2 reverse mode helps to clear postsynaptically released potassium at glutamatergic synapses. Cell Rep 2023; 42:112934. [PMID: 37537840 PMCID: PMC10480490 DOI: 10.1016/j.celrep.2023.112934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/09/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023] Open
Abstract
Extracellular potassium [K+]o elevation during synaptic activity retrogradely modifies presynaptic release and astrocytic uptake of glutamate. Hence, local K+ clearance and replenishment mechanisms are crucial regulators of glutamatergic transmission and plasticity. Based on recordings of astrocytic inward rectifier potassium current IKir and K+-sensitive electrodes as sensors of [K+]o as well as on in silico modeling, we demonstrate that the neuronal K+-Cl- co-transporter KCC2 clears local perisynaptic [K+]o during synaptic excitation by operating in an activity-dependent reversed mode. In reverse mode, KCC2 replenishes K+ in dendritic spines and complements clearance of [K+]o, therewith attenuating presynaptic glutamate release and shortening LTP. We thus demonstrate a physiological role of KCC2 in neuron-glial interactions and regulation of synaptic signaling and plasticity through the uptake of postsynaptically released K+.
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Affiliation(s)
- Egor Byvaltcev
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Mahraz Behbood
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Jan-Hendrik Schleimer
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Thomas Gensch
- Institute of Biological Information Processing 1 (IBI-1, Molecular and Cellular Physiology), Forschungszentrum Jülich, Wilhem-Jonen Straße, 52428 Jülich, Germany
| | - Alexey Semyanov
- Department of Physiology, Jiaxing University College of Medicine, Zhejiang Pro, Jiaxing 314033, China
| | - Susanne Schreiber
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany.
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8
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Peerboom C, de Kater S, Jonker N, Rieter MPJM, Wijne T, Wierenga CJ. Delaying the GABA Shift Indirectly Affects Membrane Properties in the Developing Hippocampus. J Neurosci 2023; 43:5483-5500. [PMID: 37438107 PMCID: PMC10376938 DOI: 10.1523/jneurosci.0251-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
During the first two postnatal weeks, intraneuronal chloride concentrations in rodents gradually decrease, causing a shift from depolarizing to hyperpolarizing GABA responses. The postnatal GABA shift is delayed in rodent models for neurodevelopmental disorders and in human patients, but the impact of a delayed GABA shift on the developing brain remains obscure. Here we examine the direct and indirect consequences of a delayed postnatal GABA shift on network development in organotypic hippocampal cultures made from 6- to 7-d-old mice by treating the cultures for 1 week with VU0463271, a specific inhibitor of the chloride exporter KCC2. We verified that VU treatment delayed the GABA shift and kept GABA signaling depolarizing until DIV9. We found that the structural and functional development of excitatory and inhibitory synapses at DIV9 was not affected after VU treatment. In line with previous studies, we observed that GABA signaling was already inhibitory in control and VU-treated postnatal slices. Surprisingly, 14 d after the VU treatment had ended (DIV21), we observed an increased frequency of spontaneous inhibitory postsynaptic currents in CA1 pyramidal cells, while excitatory currents were not changed. Synapse numbers and release probability were unaffected. We found that dendrite-targeting interneurons in the stratum radiatum had an elevated resting membrane potential, while pyramidal cells were less excitable compared with control slices. Our results show that depolarizing GABA signaling does not promote synapse formation after P7, and suggest that postnatal intracellular chloride levels indirectly affect membrane properties in a cell-specific manner.SIGNIFICANCE STATEMENT During brain development, the action of neurotransmitter GABA shifts from depolarizing to hyperpolarizing. This shift is a thought to play a critical role in synapse formation. A delayed shift is common in rodent models for neurodevelopmental disorders and in human patients, but its consequences for synaptic development remain obscure. Here, we delayed the GABA shift by 1 week in organotypic hippocampal cultures and carefully examined the consequences for circuit development. We find that delaying the shift has no direct effects on synaptic development, but instead leads to indirect, cell type-specific changes in membrane properties. Our data call for careful assessment of alterations in cellular excitability in neurodevelopmental disorders.
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Affiliation(s)
- Carlijn Peerboom
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Sam de Kater
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Nikki Jonker
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Marijn P J M Rieter
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Tessel Wijne
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, 6525 AJ, The Netherlands
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9
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Del Turco D, Paul MH, Schlaudraff J, Muellerleile J, Bozic F, Vuksic M, Jedlicka P, Deller T. Layer-specific changes of KCC2 and NKCC1 in the mouse dentate gyrus after entorhinal denervation. Front Mol Neurosci 2023; 16:1118746. [PMID: 37293543 PMCID: PMC10244516 DOI: 10.3389/fnmol.2023.1118746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 04/25/2023] [Indexed: 06/10/2023] Open
Abstract
The cation-chloride cotransporters KCC2 and NKCC1 regulate the intracellular Cl- concentration and cell volume of neurons and/or glia. The Cl- extruder KCC2 is expressed at higher levels than the Cl- transporter NKCC1 in mature compared to immature neurons, accounting for the developmental shift from high to low Cl- concentration and from depolarizing to hyperpolarizing currents through GABA-A receptors. Previous studies have shown that KCC2 expression is downregulated following central nervous system injury, returning neurons to a more excitable state, which can be pathological or adaptive. Here, we show that deafferentation of the dendritic segments of granule cells in the outer (oml) and middle (mml) molecular layer of the dentate gyrus via entorhinal denervation in vivo leads to cell-type- and layer-specific changes in the expression of KCC2 and NKCC1. Microarray analysis validated by reverse transcription-quantitative polymerase chain reaction revealed a significant decrease in Kcc2 mRNA in the granule cell layer 7 days post-lesion. In contrast, Nkcc1 mRNA was upregulated in the oml/mml at this time point. Immunostaining revealed a selective reduction in KCC2 protein expression in the denervated dendrites of granule cells and an increase in NKCC1 expression in reactive astrocytes in the oml/mml. The NKCC1 upregulation is likely related to the increased activity of astrocytes and/or microglia in the deafferented region, while the transient KCC2 downregulation in granule cells may be associated with denervation-induced spine loss, potentially also serving a homeostatic role via boosting GABAergic depolarization. Furthermore, the delayed KCC2 recovery might be involved in the subsequent compensatory spinogenesis.
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Affiliation(s)
- Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Mandy H. Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Jessica Schlaudraff
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Julia Muellerleile
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Fran Bozic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Mario Vuksic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
- Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
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10
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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11
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Duan GF, Tang XH, Jia M, Wu D, Shi YS. Kainate receptors GluK1 and GluK2 differentially regulate synapse morphology. Synapse 2023; 77:e22255. [PMID: 36121930 DOI: 10.1002/syn.22255] [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: 05/28/2022] [Revised: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 01/29/2023]
Abstract
The regulation of dendritic spine morphology is a critical aspect of neuronal network refinement during development and modulation of neurotransmission. Previous studies revealed that glutamatergic transmission plays a central role in synapse development. AMPA receptors and NMDA receptors regulate spine morphology in an activity dependent manner. However, whether and how Kainate receptors (KARs) regulate synapse development remains poorly understood. In this study, we found that GluK1 and GluK2 may play distinct roles in synapse development. In primary cultured hippocampal neurons, we found overexpression of the calcium-permeable GluK2(Q) receptor variant increased spine length and spine head area compared to overexpression of the calcium-impermeable GluK2(R) variant or EGFP transfected, control neurons, indicating that Q/R editing may play a role in GluK2 regulation of synapse development. Intriguingly, neurons transfected with GluK1(Q) showed decreased spine length and spine head area, while the density of dendritic spines was increased, suggesting that GluK1(Q) and GluK2(Q) have different effects on synaptic development. Swapping the critical domains between GluK2 and GluK1 demonstrated the N-terminal domain (NTD) is responsible for the different effects of GluK1 and GluK2. In conclusion, Kainate receptors GluK1 and GluK2 have distinct roles in regulating spine morphology and development, a process likely relying on the NTD.
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Affiliation(s)
- Gui-Fang Duan
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Xiao-Hui Tang
- Department of Anesthesiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Min Jia
- Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu, China
| | - Dan Wu
- Minister of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
| | - Yun Stone Shi
- Minister of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
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12
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Rigkou A, Magyar A, Speer JM, Roussa E. TGF-β2 Regulates Transcription of the K +/Cl - Cotransporter 2 (KCC2) in Immature Neurons and Its Phosphorylation at T1007 in Differentiated Neurons. Cells 2022; 11:cells11233861. [PMID: 36497119 PMCID: PMC9739967 DOI: 10.3390/cells11233861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/28/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022] Open
Abstract
KCC2 mediates extrusion of K+ and Cl- and assuresthe developmental "switch" in GABA function during neuronal maturation. However, the molecular mechanisms underlying KCC2 regulation are not fully elucidated. We investigated the impact of transforming growth factor beta 2 (TGF-β2) on KCC2 during neuronal maturation using quantitative RT-PCR, immunoblotting, immunofluorescence and chromatin immunoprecipitation in primary mouse hippocampal neurons and brain tissue from Tgf-β2-deficient mice. Inhibition of TGF-β/activin signaling downregulates Kcc2 transcript in immature neurons. In the forebrain of Tgf-β2-/- mice, expression of Kcc2, transcription factor Ap2β and KCC2 protein is downregulated. AP2β binds to Kcc2 promoter, a binding absent in Tgf-β2-/-. In hindbrain/brainstem tissue of Tgf-β2-/- mice, KCC2 phosphorylation at T1007 is increased and approximately half of pre-Bötzinger-complex neurons lack membrane KCC2 phenotypes rescued through exogenous TGF-β2. These results demonstrate that TGF-β2 regulates KCC2 transcription in immature neurons, possibly acting upstream of AP2β, and contributes to the developmental dephosphorylation of KCC2 at T1007. The present work suggests multiple and divergent roles for TGF-β2 on KCC2 during neuronal maturation and provides novel mechanistic insights for TGF-β2-mediated regulation of KCC2 gene expression, posttranslational modification and surface expression. We propose TGF-β2 as a major regulator of KCC2 with putative implications for pathophysiological conditions.
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13
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Litwa K. Shared mechanisms of neural circuit disruption in tuberous sclerosis across lifespan: Bridging neurodevelopmental and neurodegenerative pathology. Front Genet 2022; 13:997461. [PMID: 36506334 PMCID: PMC9732432 DOI: 10.3389/fgene.2022.997461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/06/2022] [Indexed: 11/27/2022] Open
Abstract
Tuberous Sclerosis (TS) is a rare genetic disorder manifesting with multiple benign tumors impacting the function of vital organs. In TS patients, dominant negative mutations in TSC1 or TSC2 increase mTORC1 activity. Increased mTORC1 activity drives tumor formation, but also severely impacts central nervous system function, resulting in infantile seizures, intractable epilepsy, and TS-associated neuropsychiatric disorders, including autism, attention deficits, intellectual disability, and mood disorders. More recently, TS has also been linked with frontotemporal dementia. In addition to TS, accumulating evidence implicates increased mTORC1 activity in the pathology of other neurodevelopmental and neurodegenerative disorders. Thus, TS provides a unique disease model to address whether developmental neural circuit abnormalities promote age-related neurodegeneration, while also providing insight into the therapeutic potential of mTORC1 inhibitors for both developing and degenerating neural circuits. In the following review, we explore the ability of both mouse and human brain organoid models to capture TS pathology, elucidate disease mechanisms, and shed light on how neurodevelopmental alterations may later contribute to age-related neurodegeneration.
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14
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Silencing KCC2 in mouse dorsal hippocampus compromises spatial and contextual memory. Neuropsychopharmacology 2022; 48:1067-1077. [PMID: 36302847 PMCID: PMC10209115 DOI: 10.1038/s41386-022-01480-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022]
Abstract
Delayed upregulation of the neuronal chloride extruder KCC2 underlies the progressive shift in GABA signaling polarity during development. Conversely, KCC2 downregulation is observed in a variety of neurological and psychiatric disorders often associated with cognitive impairment. Reduced KCC2 expression and function in mature networks may disrupt GABA signaling and promote anomalous network activities underlying these disorders. However, the causal link between KCC2 downregulation, altered brain rhythmogenesis, and cognitive function remains elusive. Here, by combining behavioral exploration with in vivo electrophysiology we assessed the impact of chronic KCC2 downregulation in mouse dorsal hippocampus and showed it compromises both spatial and contextual memory. This was associated with altered hippocampal rhythmogenesis and neuronal hyperexcitability, with increased burst firing in CA1 neurons during non-REM sleep. Reducing neuronal excitability with terbinafine, a specific Task-3 leak potassium channel opener, occluded the impairment of contextual memory upon KCC2 knockdown. Our results establish a causal relationship between KCC2 expression and cognitive performance and suggest that non-epileptiform rhythmopathies and neuronal hyperexcitability are central to the deficits caused by KCC2 downregulation in the adult mouse brain.
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15
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Miles KD, Doll CA. Chloride imbalance in Fragile X syndrome. Front Neurosci 2022; 16:1008393. [PMID: 36312023 PMCID: PMC9596984 DOI: 10.3389/fnins.2022.1008393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/20/2022] [Indexed: 11/26/2022] Open
Abstract
Developmental changes in ionic balance are associated with crucial hallmarks in neural circuit formation, including changes in excitation and inhibition, neurogenesis, and synaptogenesis. Neuronal excitability is largely mediated by ionic concentrations inside and outside of the cell, and chloride (Cl-) ions are highly influential in early neurodevelopmental events. For example, γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). However, during early development GABA can depolarize target neurons, and GABAergic depolarization is implicated in crucial neurodevelopmental processes. This developmental shift of GABAergic neurotransmission from depolarizing to hyperpolarizing output is induced by changes in Cl- gradients, which are generated by the relative expression of Cl- transporters Nkcc1 and Kcc2. Interestingly, the GABA polarity shift is delayed in Fragile X syndrome (FXS) models; FXS is one of the most common heritable neurodevelopmental disorders. The RNA binding protein FMRP, encoded by the gene Fragile X Messenger Ribonucleoprotein-1 (Fmr1) and absent in FXS, appears to regulate chloride transporter expression. This could dramatically influence FXS phenotypes, as the syndrome is hypothesized to be rooted in defects in neural circuit development and imbalanced excitatory/inhibitory (E/I) neurotransmission. In this perspective, we summarize canonical Cl- transporter expression and investigate altered gene and protein expression of Nkcc1 and Kcc2 in FXS models. We then discuss interactions between Cl- transporters and neurotransmission complexes, and how these links could cause imbalances in inhibitory neurotransmission that may alter mature circuits. Finally, we highlight current therapeutic strategies and promising new directions in targeting Cl- transporter expression in FXS patients.
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Affiliation(s)
| | - Caleb Andrew Doll
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Children’s Hospital Colorado, Aurora, CO, United States
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16
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Jones EF, Butler MG, Trendafilova D, Mendez MS, Jernigan LA, Gahtan E, Steele J. In vivo tracking of KCC2b expression during early brain development. J Comp Neurol 2022; 531:48-57. [PMID: 36217249 DOI: 10.1002/cne.25411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/03/2022] [Accepted: 08/27/2022] [Indexed: 11/07/2022]
Abstract
The neuronal chloride (Cl-) exporter, KCC2, regulates neuron excitability and development and undergoes a stereotypical pattern of delayed upregulation as neurons mature. KCC2 upregulation favors neural inhibition by establishing a negative Cl- gradient, ensuring GABA-induced Cl- currents are inward and inhibitory. We developed a zebrafish fluorescent reporter line, KCC2b:mCitrine, to track KCC2 expression in vivo during early brain development. KCC2b:mCitrine was first detected at 16 h postfertilization and by day 6 labeled most central and peripheral neurons and processes. At 20 h, expression was greatest in the soma-dense basal neuroepithelium but largely absent in apical and mantle zones where differentiation and migration primarily occur, and time lapse imaging at this stage supports a postmigration upregulation of KCC2b. Central dopamine neurons showed low KCC2b expression as observed in other species. KCC2b:mCitrine fluorescence was stable over minutes in most neurons, but brightness transients observed in single cells fit our expectation for real-time tracking of KCC2b upregulation in new neurons. To further assess whether fluorescence brightness tracks KCC2b expression, zebrafish embryos were exposed to bisphenol-A (BPA), which is known to suppress KCC2 expression. Fluorescence decreased after 6 days of BPA exposure but not after 2 or 4 days, suggesting that it is an accurate but delayed indicator of KCC2b expression. KCC2b:mCitrine zebrafish present a new method for visualizing KCC2b's complex dynamics during brain development, and potentially screening compounds aimed at modulating KCC2 expression.
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Affiliation(s)
- Emma F Jones
- Department of Psychology, Cal Poly Humboldt, Arcata, California, USA.,Department of Biology, Cal Poly Humboldt, Arcata, California, USA
| | | | | | - Mayra S Mendez
- Department of Psychology, Cal Poly Humboldt, Arcata, California, USA
| | - Luke A Jernigan
- Department of Chemistry, Cal Poly Humboldt, Arcata, California, USA
| | - Ethan Gahtan
- Department of Psychology, Cal Poly Humboldt, Arcata, California, USA.,Department of Biology, Cal Poly Humboldt, Arcata, California, USA
| | - John Steele
- Department of Biology, Cal Poly Humboldt, Arcata, California, USA
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17
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Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2. J Mol Neurosci 2022; 72:1500-1515. [PMID: 35819636 DOI: 10.1007/s12031-022-02041-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 06/07/2022] [Indexed: 10/17/2022]
Abstract
Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABAA receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABAA receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K+-Cl--cotransporter (KCC2) to the alterations in the Cl- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.
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18
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Lee KG, Rajakumar N. Partial ablation of frontal cortical subplate leads to developmental abnormalities in KCC2 in the prefrontal cortex. Mol Cell Neurosci 2022; 120:103733. [DOI: 10.1016/j.mcn.2022.103733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 04/20/2022] [Accepted: 04/23/2022] [Indexed: 10/18/2022] Open
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19
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Ba X, Ran C, Guo W, Guo J, Zeng Q, Liu T, Sun W, Xiao L, Xiong D, Huang Y, Jiang C, Hao Y. Three-Day Continuous Oxytocin Infusion Attenuates Thermal and Mechanical Nociception by Rescuing Neuronal Chloride Homeostasis via Upregulation KCC2 Expression and Function. Front Pharmacol 2022; 13:845018. [PMID: 35401174 PMCID: PMC8988046 DOI: 10.3389/fphar.2022.845018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Oxytocin (OT) and its receptor are promising targets for the treatment and prevention of the neuropathic pain. In the present study, we compared the effects of a single and continuous intrathecal infusion of OT on nerve injury-induced neuropathic pain behaviours in mice and further explore the mechanisms underlying their analgesic properties. We found that three days of continuous intrathecal OT infusion alleviated subsequent pain behaviours for 14 days, whereas a single OT injection induced a transient analgesia for 30 min, suggesting that only continuous intrathecal OT attenuated the establishment and development of neuropathic pain behaviours. Supporting this behavioural finding, continuous intrathecal infusion, but not short-term incubation of OT, reversed the nerve injury-induced depolarizing shift in Cl- reversal potential via restoring the function and expression of spinal K+-Cl- cotransporter 2 (KCC2), which may be caused by OT-induced enhancement of GABA inhibitory transmission. This result suggests that only continuous use of OT may reverse the pathological changes caused by nerve injury, thereby mechanistically blocking the establishment and development of pain. These findings provide novel evidence relevant for advancing understanding of the effects of continuous OT administration on the pathophysiology of pain.
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Affiliation(s)
- Xiyuan Ba
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Chenqiu Ran
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen, China
| | - Wenjun Guo
- Department of Pain Medicine, Shenzhen, China
| | - Jing Guo
- Department of Endocrinology and Metabolism, Shenzhen University General Hospital and Shenzhen University Academy of Clinical Medical Sciences, Shenzhen University, Shenzhen, China
| | - Qian Zeng
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Tao Liu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wuping Sun
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Lizu Xiao
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Donglin Xiong
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Yelan Huang
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen, China
| | - Changyu Jiang
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People’s Hospital, Shenzhen, China
| | - Yue Hao
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen, China
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20
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Zavalin K, Hassan A, Fu C, Delpire E, Lagrange AH. Loss of KCC2 in GABAergic Neurons Causes Seizures and an Imbalance of Cortical Interneurons. Front Mol Neurosci 2022; 15:826427. [PMID: 35370549 PMCID: PMC8966887 DOI: 10.3389/fnmol.2022.826427] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/21/2022] [Indexed: 11/24/2022] Open
Abstract
K-Cl transporter KCC2 is an important regulator of neuronal development and neuronal function at maturity. Through its canonical transporter role, KCC2 maintains inhibitory responses mediated by γ-aminobutyric acid (GABA) type A receptors. During development, late onset of KCC2 transporter activity defines the period when depolarizing GABAergic signals promote a wealth of developmental processes. In addition to its transporter function, KCC2 directly interacts with a number of proteins to regulate dendritic spine formation, cell survival, synaptic plasticity, neuronal excitability, and other processes. Either overexpression or loss of KCC2 can lead to abnormal circuit formation, seizures, or even perinatal death. GABA has been reported to be especially important for driving migration and development of cortical interneurons (IN), and we hypothesized that properly timed onset of KCC2 expression is vital to this process. To test this hypothesis, we created a mouse with conditional knockout of KCC2 in Dlx5-lineage neurons (Dlx5 KCC2 cKO), which targets INs and other post-mitotic GABAergic neurons in the forebrain starting during embryonic development. While KCC2 was first expressed in the INs of layer 5 cortex, perinatal IN migrations and laminar localization appeared to be unaffected by the loss of KCC2. Nonetheless, the mice had early seizures, failure to thrive, and premature death in the second and third weeks of life. At this age, we found an underlying change in IN distribution, including an excess number of somatostatin neurons in layer 5 and a decrease in parvalbumin-expressing neurons in layer 2/3 and layer 6. Our research suggests that while KCC2 expression may not be entirely necessary for early IN migration, loss of KCC2 causes an imbalance in cortical interneuron subtypes, seizures, and early death. More work will be needed to define the specific cellular basis for these findings, including whether they are due to abnormal circuit formation versus the sequela of defective IN inhibition.
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Affiliation(s)
- Kirill Zavalin
- Department of Neurology, School of Medicine, Vanderbilt University, Nashville, TN, United States
| | - Anjana Hassan
- Department of Neurology, School of Medicine, Vanderbilt University, Nashville, TN, United States
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Eric Delpire
- Department of Anesthesiology, School of Medicine, Vanderbilt University, Nashville, TN, United States
| | - Andre H. Lagrange
- Department of Neurology, School of Medicine, Vanderbilt University, Nashville, TN, United States,Department of Neurology, Tennessee Valley Healthcare – Veterans Affairs (TVH VA), Medical Center, Nashville, TN, United States,*Correspondence: Andre H. Lagrange,
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21
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Serranilla M, Woodin MA. Striatal Chloride Dysregulation and Impaired GABAergic Signaling Due to Cation-Chloride Cotransporter Dysfunction in Huntington’s Disease. Front Cell Neurosci 2022; 15:817013. [PMID: 35095429 PMCID: PMC8795088 DOI: 10.3389/fncel.2021.817013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Intracellular chloride (Cl–) levels in mature neurons must be tightly regulated for the maintenance of fast synaptic inhibition. In the mature central nervous system (CNS), synaptic inhibition is primarily mediated by gamma-amino butyric acid (GABA), which binds to Cl– permeable GABAA receptors (GABAARs). The intracellular Cl– concentration is primarily maintained by the antagonistic actions of two cation-chloride cotransporters (CCCs): Cl–-importing Na+-K+-Cl– co-transporter-1 (NKCC1) and Cl– -exporting K+-Cl– co-transporter-2 (KCC2). In mature neurons in the healthy brain, KCC2 expression is higher than NKCC1, leading to lower levels of intracellular Cl–, and Cl– influx upon GABAAR activation. However, in neurons of the immature brain or in neurological disorders such as epilepsy and traumatic brain injury, impaired KCC2 function and/or enhanced NKCC1 expression lead to intracellular Cl– accumulation and GABA-mediated excitation. In Huntington’s disease (HD), KCC2- and NKCC1-mediated Cl–-regulation are also altered, which leads to GABA-mediated excitation and contributes to the development of cognitive and motor impairments. This review summarizes the role of Cl– (dys)regulation in the healthy and HD brain, with a focus on the basal ganglia (BG) circuitry and CCCs as potential therapeutic targets in the treatment of HD.
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22
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Al Awabdh S, Donneger F, Goutierre M, Séveno M, Vigy O, Weinzettl P, Russeau M, Moutkine I, Lévi S, Marin P, Poncer JC. Gephyrin Interacts with the K-Cl Cotransporter KCC2 to Regulate Its Surface Expression and Function in Cortical Neurons. J Neurosci 2022; 42:166-182. [PMID: 34810232 PMCID: PMC8802937 DOI: 10.1523/jneurosci.2926-20.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 08/31/2021] [Accepted: 10/17/2021] [Indexed: 11/21/2022] Open
Abstract
The K+-Cl- cotransporter KCC2, encoded by the Slc12a5 gene, is a neuron-specific chloride extruder that tunes the strength and polarity of GABAA receptor-mediated transmission. In addition to its canonical ion transport function, KCC2 also regulates spinogenesis and excitatory synaptic function through interaction with a variety of molecular partners. KCC2 is enriched in the vicinity of both glutamatergic and GABAergic synapses, the activity of which in turn regulates its membrane stability and function. KCC2 interaction with the submembrane actin cytoskeleton via 4.1N is known to control its anchoring near glutamatergic synapses on dendritic spines. However, the molecular determinants of KCC2 clustering near GABAergic synapses remain unknown. Here, we used proteomics to identify novel KCC2 interacting proteins in the adult rat neocortex. We identified both known and novel candidate KCC2 partners, including some involved in neuronal development and synaptic transmission. These include gephyrin, the main scaffolding molecule at GABAergic synapses. Gephyrin interaction with endogenous KCC2 was confirmed by immunoprecipitation from rat neocortical extracts. We showed that gephyrin stabilizes plasmalemmal KCC2 and promotes its clustering in hippocampal neurons, mostly but not exclusively near GABAergic synapses, thereby controlling KCC2-mediated chloride extrusion. This study identifies gephyrin as a novel KCC2 anchoring molecule that regulates its membrane expression and function in cortical neurons.SIGNIFICANCE STATEMENT Fast synaptic inhibition in the brain is mediated by chloride-permeable GABAA receptors (GABAARs) and therefore relies on transmembrane chloride gradients. In neurons, these gradients are primarily maintained by the K/Cl cotransporter KCC2. Therefore, understanding the mechanisms controlling KCC2 expression and function is crucial to understand its physiological regulation and rescue its function in the pathology. KCC2 function depends on its membrane expression and clustering, but the underlying mechanisms remain unknown. We describe the interaction between KCC2 and gephyrin, the main scaffolding protein at inhibitory synapses. We show that gephyrin controls plasmalemmal KCC2 clustering and that loss of gephyrin compromises KCC2 function. Our data suggest functional units comprising GABAARs, gephyrin, and KCC2 act to regulate synaptic GABA signaling.
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Affiliation(s)
- Sana Al Awabdh
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Florian Donneger
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Marie Goutierre
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Martial Séveno
- BCM, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Oana Vigy
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Pauline Weinzettl
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
- Institute of Biotechnology, University of Applied Sciences, Krems, Austria
| | - Marion Russeau
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Imane Moutkine
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Sabine Lévi
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Philippe Marin
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Jean Christophe Poncer
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
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23
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Cherubini E, Di Cristo G, Avoli M. Dysregulation of GABAergic Signaling in Neurodevelomental Disorders: Targeting Cation-Chloride Co-transporters to Re-establish a Proper E/I Balance. Front Cell Neurosci 2022; 15:813441. [PMID: 35069119 PMCID: PMC8766311 DOI: 10.3389/fncel.2021.813441] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/30/2021] [Indexed: 01/01/2023] Open
Abstract
The construction of the brain relies on a series of well-defined genetically and experience- or activity -dependent mechanisms which allow to adapt to the external environment. Disruption of these processes leads to neurological and psychiatric disorders, which in many cases are manifest already early in postnatal life. GABA, the main inhibitory neurotransmitter in the adult brain is one of the major players in the early assembly and formation of neuronal circuits. In the prenatal and immediate postnatal period GABA, acting on GABAA receptors, depolarizes and excites targeted cells via an outwardly directed flux of chloride. In this way it activates NMDA receptors and voltage-dependent calcium channels contributing, through intracellular calcium rise, to shape neuronal activity and to establish, through the formation of new synapses and elimination of others, adult neuronal circuits. The direction of GABAA-mediated neurotransmission (depolarizing or hyperpolarizing) depends on the intracellular levels of chloride [Cl−]i, which in turn are maintained by the activity of the cation-chloride importer and exporter KCC2 and NKCC1, respectively. Thus, the premature hyperpolarizing action of GABA or its persistent depolarizing effect beyond the postnatal period, leads to behavioral deficits associated with morphological alterations and an excitatory (E)/inhibitory (I) imbalance in selective brain areas. The aim of this review is to summarize recent data concerning the functional role of GABAergic transmission in building up and refining neuronal circuits early in development and its dysfunction in neurodevelopmental disorders such as Autism Spectrum Disorders (ASDs), schizophrenia and epilepsy. In particular, we focus on novel information concerning the mechanisms by which alterations in cation-chloride co-transporters (CCC) generate behavioral and cognitive impairment in these diseases. We discuss also the possibility to re-establish a proper GABAA-mediated neurotransmission and excitatory (E)/inhibitory (I) balance within selective brain areas acting on CCC.
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Affiliation(s)
- Enrico Cherubini
- European Brain Research Institute (EBRI)-Rita Levi-Montalcini, Roma, Italy
- *Correspondence: Enrico Cherubini
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal and CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology and Neurosurgery and of Physiology, McGill University, Montreal, QC, Canada
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24
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Asraf H, Bogdanovic M, Gottesman N, Sekler I, Aizenman E, Hershfinkel M. SNAP23 regulates KCC2 membrane insertion and activity following mZnR/GPR39 activation in hippocampal neurons. iScience 2022; 25:103751. [PMID: 35118363 PMCID: PMC8800107 DOI: 10.1016/j.isci.2022.103751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/25/2021] [Accepted: 01/06/2022] [Indexed: 11/23/2022] Open
Abstract
Modulation of the neuronal K+/Cl− cotransporter 2 (KCC2) activity, which mediates Cl− export, is critical to neuronal function. Here, we demonstrate that KCC2 interacts with the SNARE protein synaptosome-associated protein 23, SNAP23, an essential component of membrane insertion machinery. Using KCC2 truncated mutants, we show that KCC2 C-terminal domain is essential for membrane targeting and SNAP23-dependent upregulation of KCC2 activity triggered by activation of the Zn2+-sensitive receptor mZnR/GPR39 in HEK293 cells. Expression of SNAP23 phosphorylation-insensitive mutants or inhibition of its upstream activator IκB kinase (IKK) prevents mZnR/GPR39 upregulation of KCC2 activity in mouse hippocampal neurons. We further find that SNAP23 interacts with Syntaxin 1A and KCC2, and that all three proteins exhibit increased membrane insertion following mZnR/GPR39 activation in neurons. Our results elucidate a G-protein-coupled receptor-dependent pathway for regulation of KCC activity, mediated via interaction with SNARE proteins. Neuronal K+/Cl− cotransporter 2 (KCC2) is regulated via interaction with SNAP23 Zn2+ enhances interaction and membrane insertion of SNAP23, Syntaxin 1A, and KCC2 Zn2+-dependent mZnR/GPR39 regulation of KCC2 requires SNAP23 phosphorylation Epithelial KCC3 regulation by ZnR/GPR39 also requires SNAP23
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25
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Lim WM, Chin EWM, Tang BL, Chen T, Goh ELK. WNK3 Maintains the GABAergic Inhibitory Tone, Synaptic Excitation and Neuronal Excitability via Regulation of KCC2 Cotransporter in Mature Neurons. Front Mol Neurosci 2021; 14:762142. [PMID: 34858138 PMCID: PMC8631424 DOI: 10.3389/fnmol.2021.762142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The activation of chloride (Cl−)permeable gamma (γ)-aminobutyric acid type A(GABAA) receptors induces synaptic inhibition in mature and excitation in immature neurons. This developmental “switch” in GABA function controlled by its polarity depends on the postnatal decrease in intraneuronal Cl− concentration mediated by KCC2, a member of cation-chloride cotransporters (CCCs). The serine-threonine kinase WNK3 (With No Lysine [K]), is a potent regulator of all CCCs and is expressed in neurons. Here, we characterized the functions of WNK3 and its role in GABAergic signaling in cultured embryonic day 18 (E18) hippocampal neurons. We observed a decrease in WNK3 expression as neurons mature. Knocking down of WNK3 significantly hyperpolarized EGABA in mature neurons (DIV13–15) but had no effect on immature neurons (DIV6–8). This hyperpolarized EGABA in WNK3-deficient neurons was not due to the total expression of NKCC1 and KCC2, that remained unchanged. However, there was a reduction in phosphorylated KCC2 at the membrane, suggesting an increase in KCC2 chloride export activity. Furthermore, hyperpolarized EGABA observed in WNK3-deficient neurons can be reversed by the KCC2 inhibitor, VU024055, thus indicating that WNK3 acts through KCC2 to influence EGABA. Notably, WNK3 knockdown resulted in morphological changes in mature but not immature neurons. Electrophysiological characterization of WNK3-deficient mature neurons revealed reduced capacitances but increased intrinsic excitability and synaptic excitation. Hence, our study demonstrates that WNK3 maintains the “adult” GABAergic inhibitory tone in neurons and plays a role in the morphological development of neurons and excitability.
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Affiliation(s)
- Wee Meng Lim
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore
| | - Eunice W M Chin
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Bor Luen Tang
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tingting Chen
- School of Pharmacy, Nantong University, Nantong, China
| | - Eyleen L K Goh
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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26
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Verma V, Kumar MJV, Sharma K, Rajaram S, Muddashetty R, Manjithaya R, Behnisch T, Clement JP. Pharmacological intervention in young adolescents rescues synaptic physiology and behavioural deficits in Syngap1 +/- mice. Exp Brain Res 2021; 240:289-309. [PMID: 34739555 DOI: 10.1007/s00221-021-06254-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 10/21/2021] [Indexed: 01/04/2023]
Abstract
Haploinsufficiency in SYNGAP1 is implicated in intellectual disability (ID) and autism spectrum disorder (ASD) and affects the maturation of dendritic spines. The abnormal spine development has been suggested to cause a disbalance of excitatory and inhibitory (E/I) neurotransmission at distinct developmental periods. In addition, E/I imbalances in Syngap1+/- mice might be due to abnormalities in K+-Cl- co-transporter function (NKCC1, KCC2), in a maner similar to the murine models of Fragile-X and Rett syndromes. To study whether an altered intracellular chloride ion concentration represents an underlying mechanism of modified function of GABAergic synapses in Dentate Gyrus Granule Cells of Syngap1+/- recordings were performed at different developmental stages of the mice. We observed depolarised neurons at P14-15 as illustrated by decreased Cl- reversal potential in Syngap1+/- mice. The KCC2 expression was decreased compared to Wild-type (WT) mice at P14-15. The GSK-3β inhibitor, 6-bromoindirubin-3'-oxime (6BIO) that crosses the blood-brain barrier, was tested to restore the function of GABAergic synapses. We discovered that the intraperitoneal administration of 6BIO during the critical period or young adolescents [P30 to P80 (4-week to 10-week)] normalised an altered E/I balance, the deficits of synaptic plasticity, and behavioural performance like social novelty, anxiety, and memory of the Syngap1+/- mice. In summary, altered GABAergic function in Syngap1+/- mice is due to reduced KCC2 expression leading to an increase in the intracellular chloride concentration that can be counteracted by the 6BIO, which restored cognitive, emotional, and social symptoms by pharmacological intervention, particularly in adulthood.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - M J Vijay Kumar
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Kavita Sharma
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Sridhar Rajaram
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Ravi Muddashetty
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, 560065, India
| | - Ravi Manjithaya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.,Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Thomas Behnisch
- Institutes of Brain Sciences, Fudan University, Shanghai, 200032, China
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.
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27
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Yang Q, Liu J, Wang Z. 4.1N-Mediated Interactions and Functions in Nerve System and Cancer. Front Mol Biosci 2021; 8:711302. [PMID: 34589518 PMCID: PMC8473747 DOI: 10.3389/fmolb.2021.711302] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/16/2021] [Indexed: 01/05/2023] Open
Abstract
Scaffolding protein 4.1N is a neuron-enriched 4.1 homologue. 4.1N contains three conserved domains, including the N-terminal 4.1-ezrin-radixin-moesin (FERM) domain, internal spectrin–actin–binding (SAB) domain, and C-terminal domain (CTD). Interspersed between the three domains are nonconserved domains, including U1, U2, and U3. The role of 4.1N was first reported in the nerve system. Then, extensive studies reported the role of 4.1N in cancers and other diseases. 4.1N performs numerous vital functions in signaling transduction by interacting, locating, supporting, and coordinating different partners and is involved in the molecular pathogenesis of various diseases. In this review, recent studies on the interactions between 4.1N and its contactors (including the α7AChr, IP3R1, GluR1/4, GluK1/2/3, mGluR8, KCC2, D2/3Rs, CASK, NuMA, PIKE, IP6K2, CAM 1/3, βII spectrin, flotillin-1, pp1, and 14-3-3) and the 4.1N-related biological functions in the nerve system and cancers are specifically and comprehensively discussed. This review provides critical detailed mechanistic insights into the role of 4.1N in disease relationships.
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Affiliation(s)
- Qin Yang
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,School of Medical Laboratory, Shao Yang University, Shaoyang, China
| | - Jing Liu
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zi Wang
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
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28
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Ning S, Hua L, Ji Z, Fan D, Meng X, Li Z, Wang Q, Guo Z. Protein 4.1 family and ion channel proteins interact to regulate the process of heart failure in rats. Acta Histochem 2021; 123:151748. [PMID: 34271280 DOI: 10.1016/j.acthis.2021.151748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023]
Abstract
Heart failure (HF) is a major cause of death in cardiovascular diseases worldwide, and its molecular mechanisms and effective prevention strategies remain to be further studied. The myocardial cytoskeleton plays a pivotal role in many heart diseases. However, little is known about the function of the membrane cytoskeleton 4.1 protein family and related regulatory mechanisms in the pathogenesis of HF. In this study, we detected the localization and expression of the protein 4.1 family and ion channel proteins in a rat HF model induced by doxorubicin (DOX), and studied the interactions between them. Our results showed that compared with the control group, the HF group displayed an increased expression level of protein 4.1R and decreased levels of protein 4.1 G and 4.1 N. The Nav1.5 protein levels were significantly increased, while the SERCA2a and Cav1.2 protein levels were significantly decreased in the HF group. Furthermore, there is co-localization and interaction between protein 4.1R and Nav1.5, protein 4.1 G and SERCA2a, protein 4.1 N and Cav1.2, respectively. Taken together, the results indicated that the protein 4.1 family might be involved in the occurrence and development of HF through its interaction with ion channel proteins, suggesting that 4.1 proteins may serve as a novel therapeutic target for HF.
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Affiliation(s)
- Shuwei Ning
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China
| | - Lei Hua
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China
| | - Zhenyu Ji
- Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, China
| | - Dandan Fan
- Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, China
| | - Xiangguang Meng
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China
| | - Zhiying Li
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China
| | - Qian Wang
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China
| | - Zhikun Guo
- Zhengzhou Key Laboratory, Zhengzhou No. 7 People's Hospital, Zhengzhou, 450016, China; Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang, 453003, China.
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29
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Castillon C, Gonzalez L, Domenichini F, Guyon S, Da Silva K, Durand C, Lestaevel P, Vaillend C, Laroche S, Barnier JV, Poirier R. The intellectual disability PAK3 R67C mutation impacts cognitive functions and adult hippocampal neurogenesis. Hum Mol Genet 2021; 29:1950-1968. [PMID: 31943058 DOI: 10.1093/hmg/ddz296] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/29/2019] [Accepted: 12/02/2019] [Indexed: 12/11/2022] Open
Abstract
The link between mutations associated with intellectual disability (ID) and the mechanisms underlying cognitive dysfunctions remains largely unknown. Here, we focused on PAK3, a serine/threonine kinase whose gene mutations cause X-linked ID. We generated a new mutant mouse model bearing the missense R67C mutation of the Pak3 gene (Pak3-R67C), known to cause moderate to severe ID in humans without other clinical signs and investigated hippocampal-dependent memory and adult hippocampal neurogenesis. Adult male Pak3-R67C mice exhibited selective impairments in long-term spatial memory and pattern separation function, suggestive of altered hippocampal neurogenesis. A delayed non-matching to place paradigm testing memory flexibility and proactive interference, reported here as being adult neurogenesis-dependent, revealed a hypersensitivity to high interference in Pak3-R67C mice. Analyzing adult hippocampal neurogenesis in Pak3-R67C mice reveals no alteration in the first steps of adult neurogenesis, but an accelerated death of a population of adult-born neurons during the critical period of 18-28 days after their birth. We then investigated the recruitment of hippocampal adult-born neurons after spatial memory recall. Post-recall activation of mature dentate granule cells in Pak3-R67C mice was unaffected, but a complete failure of activation of young DCX + newborn neurons was found, suggesting they were not recruited during the memory task. Decreased expression of the KCC2b chloride cotransporter and altered dendritic development indicate that young adult-born neurons are not fully functional in Pak3-R67C mice. We suggest that these defects in the dynamics and learning-associated recruitment of newborn hippocampal neurons may contribute to the selective cognitive deficits observed in this mouse model of ID.
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Affiliation(s)
- Charlotte Castillon
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Laurine Gonzalez
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Florence Domenichini
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Sandrine Guyon
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Kevin Da Silva
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Christelle Durand
- Institute for Radiological Protection and Nuclear Safety (IRSN), Research department on the Biological and Health Effects of Ionizing Radiation (SESANE), Laboratory of experimental Radiotoxicology and Radiobiology (LRTOX), 92260 Fontenay-aux-Roses, France
| | - Philippe Lestaevel
- Institute for Radiological Protection and Nuclear Safety (IRSN), Research department on the Biological and Health Effects of Ionizing Radiation (SESANE), Laboratory of experimental Radiotoxicology and Radiobiology (LRTOX), 92260 Fontenay-aux-Roses, France
| | - Cyrille Vaillend
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Serge Laroche
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Jean-Vianney Barnier
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
| | - Roseline Poirier
- Paris-Saclay Neuroscience Institute (Neuro-PSI), UMR 9197, CNRS, University of Paris-Sud, University of Paris-Saclay, F-91405 Orsay, France
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30
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Kipnis PA, Kadam SD. Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures. Aging Dis 2021; 12:1056-1069. [PMID: 34221549 PMCID: PMC8219493 DOI: 10.14336/ad.2021.0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is associated with a multitude of acquired or genetic neurological disorders characterized by a predisposition to spontaneous recurrent seizures. An estimated 15 million patients worldwide have ongoing seizures despite optimal management and are classified as having refractory epilepsy. Early-life seizures like those caused by perinatal hypoxic ischemic encephalopathy (HIE) remain a clinical challenge because although transient, they are difficult to treat and associated with poor neurological outcomes. Pediatric epilepsy syndromes are consistently associated with intellectual disability and neurocognitive comorbidities. HIE and arterial ischemic stroke are the most common causes of seizures in term neonates and account for 7.5-20% of neonatal seizures. Standard first-line treatments such as phenobarbital (PB) and phenytoin fail to curb seizures in ~50% of neonates. In the long-term, HIE can result in hippocampal sclerosis and temporal lobe epilepsy (TLE), which is the most common adult epilepsy, ~30% of which is associated with refractory seizures. For patients with refractory TLE seizures, a viable option is the surgical resection of the epileptic foci. Novel insights gained from investigating the developmental role of Cl- cotransporter function have helped to elucidate some of the mechanisms underlying the emergence of refractory seizures in both HIE and TLE. KCC2 as the chief Cl- extruder in neurons is critical for enabling strong hyperpolarizing synaptic inhibition in the brain and has been implicated in the pathophysiology underlying both conditions. More recently, KCC2 function has become a novel therapeutic target to combat refractory seizures.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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31
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The role of GABAergic signalling in neurodevelopmental disorders. Nat Rev Neurosci 2021; 22:290-307. [PMID: 33772226 PMCID: PMC9001156 DOI: 10.1038/s41583-021-00443-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2021] [Indexed: 02/08/2023]
Abstract
GABAergic inhibition shapes the connectivity, activity and plasticity of the brain. A series of exciting new discoveries provides compelling evidence that disruptions in a number of key facets of GABAergic inhibition have critical roles in the aetiology of neurodevelopmental disorders (NDDs). These facets include the generation, migration and survival of GABAergic neurons, the formation of GABAergic synapses and circuit connectivity, and the dynamic regulation of the efficacy of GABAergic signalling through neuronal chloride transporters. In this Review, we discuss recent work that elucidates the functions and dysfunctions of GABAergic signalling in health and disease, that uncovers the contribution of GABAergic neural circuit dysfunction to NDD aetiology and that leverages such mechanistic insights to advance precision medicine for the treatment of NDDs.
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32
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Kainate receptors in the developing neuronal networks. Neuropharmacology 2021; 195:108585. [PMID: 33910033 DOI: 10.1016/j.neuropharm.2021.108585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022]
Abstract
Kainate receptors (KARs) are highly expressed in the immature brain and have unique developmentally regulated functions that may be important in linking neuronal activity to morphogenesis during activity-dependent fine-tuning of the synaptic connectivity. Altered expression of KARs in the developing neural network leads to changes in glutamatergic connectivity and network excitability, which may lead to long-lasting changes in behaviorally relevant circuitries in the brain. Here, we summarize the current knowledge on physiological and morphogenic functions described for different types of KARs at immature neural circuitries, focusing on their roles in modulating synaptic transmission and plasticity as well as circuit maturation in the rodent hippocampus and amygdala. Finally, we discuss the emerging evidence suggesting that malfunction of KARs in the immature brain may contribute to the pathophysiology underlying developmentally originating neurological disorders.
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33
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Eckert P, Marchetta P, Manthey MK, Walter MH, Jovanovic S, Savitska D, Singer W, Jacob MH, Rüttiger L, Schimmang T, Milenkovic I, Pilz PKD, Knipper M. Deletion of BDNF in Pax2 Lineage-Derived Interneuron Precursors in the Hindbrain Hampers the Proportion of Excitation/Inhibition, Learning, and Behavior. Front Mol Neurosci 2021; 14:642679. [PMID: 33841098 PMCID: PMC8033028 DOI: 10.3389/fnmol.2021.642679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/26/2021] [Indexed: 12/16/2022] Open
Abstract
Numerous studies indicate that deficits in the proper integration or migration of specific GABAergic precursor cells from the subpallium to the cortex can lead to severe cognitive dysfunctions and neurodevelopmental pathogenesis linked to intellectual disabilities. A different set of GABAergic precursors cells that express Pax2 migrate to hindbrain regions, targeting, for example auditory or somatosensory brainstem regions. We demonstrate that the absence of BDNF in Pax2-lineage descendants of BdnfPax2KOs causes severe cognitive disabilities. In BdnfPax2KOs, a normal number of parvalbumin-positive interneurons (PV-INs) was found in the auditory cortex (AC) and hippocampal regions, which went hand in hand with reduced PV-labeling in neuropil domains and elevated activity-regulated cytoskeleton-associated protein (Arc/Arg3.1; here: Arc) levels in pyramidal neurons in these same regions. This immaturity in the inhibitory/excitatory balance of the AC and hippocampus was accompanied by elevated LTP, reduced (sound-induced) LTP/LTD adjustment, impaired learning, elevated anxiety, and deficits in social behavior, overall representing an autistic-like phenotype. Reduced tonic inhibitory strength and elevated spontaneous firing rates in dorsal cochlear nucleus (DCN) brainstem neurons in otherwise nearly normal hearing BdnfPax2KOs suggests that diminished fine-grained auditory-specific brainstem activity has hampered activity-driven integration of inhibitory networks of the AC in functional (hippocampal) circuits. This leads to an inability to scale hippocampal post-synapses during LTP/LTD plasticity. BDNF in Pax2-lineage descendants in lower brain regions should thus be considered as a novel candidate for contributing to the development of brain disorders, including autism.
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Affiliation(s)
- Philipp Eckert
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Philine Marchetta
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Marie K Manthey
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany.,Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, United States
| | - Michael H Walter
- Department for Animal Physiology, Institute of Neurobiology, University of Tübingen, Tübingen, Germany
| | - Sasa Jovanovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Daria Savitska
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Michele H Jacob
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, United States
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Thomas Schimmang
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Ivan Milenkovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Peter K D Pilz
- Department for Animal Physiology, Institute of Neurobiology, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
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34
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Virtanen MA, Uvarov P, Mavrovic M, Poncer JC, Kaila K. The Multifaceted Roles of KCC2 in Cortical Development. Trends Neurosci 2021; 44:378-392. [PMID: 33640193 DOI: 10.1016/j.tins.2021.01.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/29/2020] [Accepted: 01/19/2021] [Indexed: 02/06/2023]
Abstract
KCC2, best known as the neuron-specific chloride-extruder that sets the strength and polarity of GABAergic currents during neuronal maturation, is a multifunctional molecule that can regulate cytoskeletal dynamics via its C-terminal domain (CTD). We describe the molecular and cellular mechanisms involved in the multiple functions of KCC2 and its splice variants, ranging from developmental apoptosis and the control of early network events to the formation and plasticity of cortical dendritic spines. The versatility of KCC2 actions at the cellular and subcellular levels is also evident in mature neurons during plasticity, disease, and aging. Thus, KCC2 has emerged as one of the most important molecules that shape the overall neuronal phenotype.
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Affiliation(s)
- Mari A Virtanen
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Pavel Uvarov
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Martina Mavrovic
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland; Department of Molecular Medicine, University of Oslo, 0372 Oslo, Norway
| | - Jean Christophe Poncer
- INSERM, UMRS 1270, 75005 Paris, France; Sorbonne Université, 75005 Paris, France; Institut du Fer à Moulin, 75005 Paris, France
| | - Kai Kaila
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland.
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35
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Zhang S, Zhou J, Zhang Y, Liu T, Friedel P, Zhuo W, Somasekharan S, Roy K, Zhang L, Liu Y, Meng X, Deng H, Zeng W, Li G, Forbush B, Yang M. The structural basis of function and regulation of neuronal cotransporters NKCC1 and KCC2. Commun Biol 2021; 4:226. [PMID: 33597714 PMCID: PMC7889885 DOI: 10.1038/s42003-021-01750-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/22/2021] [Indexed: 11/08/2022] Open
Abstract
NKCC and KCC transporters mediate coupled transport of Na++K++Cl- and K++Cl- across the plasma membrane, thus regulating cell Cl- concentration and cell volume and playing critical roles in transepithelial salt and water transport and in neuronal excitability. The function of these transporters has been intensively studied, but a mechanistic understanding has awaited structural studies of the transporters. Here, we present the cryo-electron microscopy (cryo-EM) structures of the two neuronal cation-chloride cotransporters human NKCC1 (SLC12A2) and mouse KCC2 (SLC12A5), along with computational analysis and functional characterization. These structures highlight essential residues in ion transport and allow us to propose mechanisms by which phosphorylation regulates transport activity.
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Affiliation(s)
- Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jun Zhou
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuebin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Tianya Liu
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Perrine Friedel
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Wei Zhuo
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Suma Somasekharan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Kasturi Roy
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yang Liu
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xianbin Meng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wenwen Zeng
- Center for Life Sciences, Institute for Immunology and School of Medicine, Tsinghua University, Beijing, China
| | - Guohui Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Biff Forbush
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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36
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Peerboom C, Wierenga CJ. The postnatal GABA shift: A developmental perspective. Neurosci Biobehav Rev 2021; 124:179-192. [PMID: 33549742 DOI: 10.1016/j.neubiorev.2021.01.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/13/2021] [Accepted: 01/28/2021] [Indexed: 12/13/2022]
Abstract
GABA is the major inhibitory neurotransmitter that counterbalances excitation in the mature brain. The inhibitory action of GABA relies on the inflow of chloride ions (Cl-), which hyperpolarizes the neuron. In early development, GABA signaling induces outward Cl- currents and is depolarizing. The postnatal shift from depolarizing to hyperpolarizing GABA is a pivotal event in brain development and its timing affects brain function throughout life. Altered timing of the postnatal GABA shift is associated with several neurodevelopmental disorders. Here, we argue that the postnatal shift from depolarizing to hyperpolarizing GABA represents the final shift in a sequence of GABA shifts, regulating proliferation, migration, differentiation, and finally plasticity of developing neurons. Each developmental GABA shift ensures that the instructive role of GABA matches the circumstances of the developing network. Sensory input may be a crucial factor in determining proper timing of the postnatal GABA shift. A developmental perspective is necessary to interpret the full consequences of a mismatch between connectivity, activity and GABA signaling during brain development.
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Affiliation(s)
- Carlijn Peerboom
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands.
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37
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Chakraborty M, Asraf H, Sekler I, Hershfinkel M. ZnR/GPR39 controls cell migration by orchestrating recruitment of KCC3 into protrusions, re-organization of actin and activation of MMP. Cell Calcium 2021; 94:102330. [PMID: 33465674 DOI: 10.1016/j.ceca.2020.102330] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 11/30/2020] [Indexed: 12/23/2022]
Abstract
Actin re-organization and degradation of extracellular matrix by metalloproteases (MMPs) facilitate formation of cellular protrusions that are required for cell proliferation and migration. We find that Zn2+ activation of the Gq-coupled receptor ZnR/GPR39 controls these processes by regulating K+/Cl- co-transporter KCC3, which modulates cell volume. Silencing of KCC3 expression or activity reverses ZnR/GPR39 enhancement of cell proliferation, migration and invasion through Matrigel. Activation of ZnR/GPR39 recruits KCC3 into F-actin rich membrane protrusions, suggesting that it can locally control volume changes. Immunofluorescence analysis indicates that Zn2+ activation of ZnR/GPR39 and KCC3 are required to enhance formation of F-actin stress fibers and cellular protrusions. In addition, ZnR/GPR39 upregulation of KCC3-dependent transport increases the activity of matrix metalloproteases MMP2 and MMP9. Our study establishes a mechanism in which ZnR/GPR39 orchestrates localization and activation of KCC3, formation of F-actin rich cell protrusions and activation of MMPs, and thereby controls cell proliferation and migration.
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Affiliation(s)
- Moumita Chakraborty
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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38
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Barbour AJ, Nass SR, Hahn YK, Hauser KF, Knapp PE. Restoration of KCC2 Membrane Localization in Striatal Dopamine D2 Receptor-Expressing Medium Spiny Neurons Rescues Locomotor Deficits in HIV Tat-Transgenic Mice. ASN Neuro 2021; 13:17590914211022089. [PMID: 34445881 PMCID: PMC8404672 DOI: 10.1177/17590914211022089] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 04/23/2021] [Accepted: 05/06/2021] [Indexed: 11/17/2022] Open
Abstract
People infected with HIV (PWH) are highly susceptible to striatal and hippocampal damage. Motor and memory impairments are common among these patients, likely as behavioral manifestations of damage to these brain regions. GABAergic dysfunction from HIV infection and viral proteins such as transactivator of transcription (Tat) have been well documented. We recently demonstrated that the neuron specific Cl- extruder, K+ Cl- cotransporter 2 (KCC2), is diminished after exposure to HIV proteins, including Tat, resulting in disrupted GABAAR-mediated hyperpolarization and inhibition. Here, we utilized doxycycline (DOX)-inducible, GFAP-driven HIV-1 Tat transgenic mice to further explore this phenomenon. After two weeks of Tat expression, we found no changes in hippocampal KCC2 levels, but a significant decrease in the striatum that was associated with hyperlocomotion in the open field assay. We were able to restore KCC2 activity and baseline locomotion with the KCC2 enhancer, CLP290. Additionally, we found that CLP290, whose mechanism of action has yet to be described, acts to restore phosphorylation of serine 940 resulting in increased KCC2 membrane localization. We also examined neuronal subpopulation contributions to the noted effects and found significant differences. Dopamine D2 receptor-expressing medium spiny neurons (MSNs) were selectively vulnerable to Tat-induced KCC2 loss, with no changes observed in dopamine D1 receptor-expressing MSNs. These results suggest that disinhibition/diminished hyperpolarization of dopamine D2 receptor-expressing MSNs can manifest as increased locomotion in this context. They further suggest that KCC2 activity might be a therapeutic target to alleviate motor disturbances related to HIV.
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Affiliation(s)
- Aaron J. Barbour
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
| | - Sara R. Nass
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
| | - Yun K. Hahn
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
| | - Kurt F. Hauser
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
| | - Pamela E. Knapp
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
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39
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Belaïdouni Y, Diabira D, Zhang J, Graziano JC, Bader F, Montheil A, Menuet C, Wayman GA, Gaiarsa JL. The Chloride Homeostasis of CA3 Hippocampal Neurons Is Not Altered in Fully Symptomatic Mepc2-null Mice. Front Cell Neurosci 2021; 15:724976. [PMID: 34602980 PMCID: PMC8484709 DOI: 10.3389/fncel.2021.724976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/27/2021] [Indexed: 02/05/2023] Open
Abstract
Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused mainly by mutations in the MECP2 gene. Mouse models of RTT show reduced expression of the cation-chloride cotransporter KCC2 and altered chloride homeostasis at presymptomatic stages. However, whether these alterations persist to late symptomatic stages has not been studied. Here we assess KCC2 and NKCC1 expressions and chloride homeostasis in the hippocampus of early [postnatal (P) day 30-35] and late (P50-60) symptomatic male Mecp2-null (Mecp2 -/y) mice. We found (i) no difference in the relative amount, but an over-phosphorylation, of KCC2 and NKCC1 between wild-type (WT) and Mecp2 -/y hippocampi and (ii) no difference in the inhibitory strength, nor reversal potential, of GABA A -receptor-mediated responses in Mecp2 -/y CA3 pyramidal neurons compared to WT at any stages studied. Altogether, these data indicate the presence of a functional chloride extrusion mechanism in Mecp2 -/y CA3 pyramidal neurons at symptomatic stages.
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Affiliation(s)
- Yasmine Belaïdouni
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
| | - Diabe Diabira
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter, United Kingdom
| | - Jean-Charles Graziano
- Aix-Marseille University 105, Institut Paoli Calmettes, U1068, Institut National de la Santé et de la Recherche Médicale U7258, Centre National de Recherche Scientifique, Centre de Recherche en Cancérologie de Marseille, Marseille, France
| | - Francesca Bader
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
| | - Aurelie Montheil
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
| | - Clément Menuet
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
| | - Gary A. Wayman
- Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, United States
| | - Jean-Luc Gaiarsa
- Aix-Marseille University UMR 1249, Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale Unité 1249, Parc Scientifique de Luminy, Marseille, France
- *Correspondence: Jean-Luc Gaiarsa,
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40
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Kontou G, Josephine Ng SF, Cardarelli RA, Howden JH, Choi C, Ren Q, Rodriguez Santos MA, Bope CE, Dengler JS, Kelley MR, Davies PA, Kittler JT, Brandon NJ, Moss SJ, Smalley JL. KCC2 is required for the survival of mature neurons but not for their development. J Biol Chem 2021; 296:100364. [PMID: 33539918 PMCID: PMC7949141 DOI: 10.1016/j.jbc.2021.100364] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
Abstract
The K+/Cl- cotransporter KCC2 (SLC12A5) allows mature neurons in the CNS to maintain low intracellular Cl- levels that are critical in mediating fast hyperpolarizing synaptic inhibition via type A γ-aminobutyric acid receptors (GABAARs). In accordance with this, compromised KCC2 activity results in seizures, but whether such deficits directly contribute to the subsequent changes in neuronal structure and viability that lead to epileptogenesis remains to be assessed. Canonical hyperpolarizing GABAAR currents develop postnatally, which reflect a progressive increase in KCC2 expression levels and activity. To investigate the role that KCC2 plays in regulating neuronal viability and architecture, we have conditionally ablated KCC2 expression in developing and mature neurons. Decreasing KCC2 expression in mature neurons resulted in the rapid activation of the extrinsic apoptotic pathway. Intriguingly, direct pharmacological inhibition of KCC2 in mature neurons was sufficient to rapidly induce apoptosis, an effect that was not abrogated via blockade of neuronal depolarization using tetrodotoxin (TTX). In contrast, ablating KCC2 expression in immature neurons had no discernable effects on their subsequent development, arborization, or dendritic structure. However, removing KCC2 in immature neurons was sufficient to ablate the subsequent postnatal development of hyperpolarizing GABAAR currents. Collectively, our results demonstrate that KCC2 plays a critical role in neuronal survival by limiting apoptosis, and mature neurons are highly sensitive to the loss of KCC2 function. In contrast, KCC2 appears to play a minimal role in mediating neuronal development or architecture.
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Affiliation(s)
- Georgina Kontou
- AstraZeneca-Tufts Laboratory of Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Shu Fun Josephine Ng
- AstraZeneca-Tufts Laboratory of Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ross A Cardarelli
- AstraZeneca-Tufts Laboratory of Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Jack H Howden
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK
| | - Catherine Choi
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Qiu Ren
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | - Christopher E Bope
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Jake S Dengler
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Matt R Kelley
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Josef T Kittler
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK
| | - Nicholas J Brandon
- AstraZeneca-Tufts Laboratory of Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Neuroscience, IMED Biotech Unit, AstraZeneca, Boston, Massachusetts, USA
| | - Stephen J Moss
- AstraZeneca-Tufts Laboratory of Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA; Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK.
| | - Joshua L Smalley
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
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41
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Wan L, Chen L, Yu J, Wang G, Wu Z, Qian B, Liu X, Wang Y. Coordinated downregulation of KCC2 and GABA A receptor contributes to inhibitory dysfunction during seizure induction. Biochem Biophys Res Commun 2020; 532:489-495. [PMID: 32892950 DOI: 10.1016/j.bbrc.2020.08.082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 01/25/2023]
Abstract
The GABAA receptor (GABAAR) is the main inhibitory receptor in the adult mammalian brain. GABAAR function is dependent on its expression, distribution, and the chloride (Cl-) transmembrane gradient, which is determined by the potassium-chloride cotransporter 2 (KCC2) in the adult brain. KCC2 and GABAAR are downregulated in an activity-dependent manner during seizure induction. Functionally, KCC2 and GABAAR are closely related membrane proteins which modulate GABAergic inhibition. However, it remains unclear how their downregulation during seizure induction is coordinated. This study aimed to assess this interaction. Our results revealed that KCC2 and GABAAR were simultaneously downregulated in both in vivo and in vitro seizure models induced by the convulsant cyclothazide (CTZ), which was at least partly due to structural coupling in hippocampal neuronal membranes. Immunohistochemistry revealed colocalization of gephyrin with KCC2 and co-immunoprecipitation exhibited a direct coupling between GABAAR α1-subunit and KCC2 protein in hippocampal cell membranes. KCC2 specific short hairpin RNA (KCC2-shRNA) was employed to specifically reduce the expression of KCC2 in cultured hippocampal neurons. This resulted in a significant reduction in KCC2-independent GABAergic miniature inhibitory post-synaptic current (mIPSC) amplitude in shKCC2-transfected neurons. Further, pre-treatment with furosemide, a KCC2 inhibitor, during CTZ stimulation followed by washout significantly prevented convulsant stimulation-induced membrane KCC2 downregulation and significantly attenuated GABAAR downregulation concomitant with recovery of suppressed KCC2-independent GABAergic mIPSC amplitude. Our results suggest that the coordinated downregulation of KCC2 and GABAAR during seizure induction exerts a strong functional impact on GABAAR, highlighting an important regulatory mechanism in epilepsy.
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Affiliation(s)
- Li Wan
- Rehabilitation Center, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, 518035, China.
| | - Lulan Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Zheng Wu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Binbin Qian
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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42
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Smalley JL, Kontou G, Choi C, Ren Q, Albrecht D, Abiraman K, Santos MAR, Bope CE, Deeb TZ, Davies PA, Brandon NJ, Moss SJ. Isolation and Characterization of Multi-Protein Complexes Enriched in the K-Cl Co-transporter 2 From Brain Plasma Membranes. Front Mol Neurosci 2020; 13:563091. [PMID: 33192291 PMCID: PMC7643010 DOI: 10.3389/fnmol.2020.563091] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Kcc2 plays a critical role in determining the efficacy of synaptic inhibition, however, the cellular mechanisms neurons use to regulate its membrane trafficking, stability and activity are ill-defined. To address these issues, we used affinity purification to isolate stable multi-protein complexes of K-Cl Co-transporter 2 (Kcc2) from the plasma membrane of murine forebrain. We resolved these using blue-native polyacrylamide gel electrophoresis (BN-PAGE) coupled to LC-MS/MS and label-free quantification. Data are available via ProteomeXchange with identifier PXD021368. Purified Kcc2 migrated as distinct molecular species of 300, 600, and 800 kDa following BN-PAGE. In excess of 90% coverage of the soluble N- and C-termini of Kcc2 was obtained. In total we identified 246 proteins significantly associated with Kcc2. The 300 kDa species largely contained Kcc2, which is consistent with a dimeric quaternary structure for this transporter. The 600 and 800 kDa species represented stable multi-protein complexes of Kcc2. We identified a set of novel structural, ion transporting, immune related and signaling protein interactors, that are present at both excitatory and inhibitory synapses, consistent with the proposed localization of Kcc2. These included spectrins, C1qa/b/c and the IP3 receptor. We also identified interactors more directly associated with phosphorylation; Akap5, Akap13, and Lmtk3. Finally, we used LC-MS/MS on the same purified endogenous plasma membrane Kcc2 to detect phosphorylation sites. We detected 11 sites with high confidence, including known and novel sites. Collectively our experiments demonstrate that Kcc2 is associated with components of the neuronal cytoskeleton and signaling molecules that may act to regulate transporter membrane trafficking, stability, and activity.
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Affiliation(s)
- Joshua L Smalley
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Georgina Kontou
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,AstraZeneca Tufts Lab for Basic and Translational Neuroscience, Boston, MA, United States
| | - Catherine Choi
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Qiu Ren
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - David Albrecht
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,AstraZeneca Tufts Lab for Basic and Translational Neuroscience, Boston, MA, United States
| | - Krithika Abiraman
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,AstraZeneca Tufts Lab for Basic and Translational Neuroscience, Boston, MA, United States
| | | | - Christopher E Bope
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Tarek Z Deeb
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,AstraZeneca Tufts Lab for Basic and Translational Neuroscience, Boston, MA, United States
| | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Nicholas J Brandon
- AstraZeneca Tufts Lab for Basic and Translational Neuroscience, Boston, MA, United States.,Neuroscience, IMED Biotech Unit, AstraZeneca, Boston, MA, United States
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
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43
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Murillo-de-Ozores AR, Chávez-Canales M, de Los Heros P, Gamba G, Castañeda-Bueno M. Physiological Processes Modulated by the Chloride-Sensitive WNK-SPAK/OSR1 Kinase Signaling Pathway and the Cation-Coupled Chloride Cotransporters. Front Physiol 2020; 11:585907. [PMID: 33192599 PMCID: PMC7606576 DOI: 10.3389/fphys.2020.585907] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
The role of Cl– as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl– in signaling is the modulation of the With-No-Lysine (K) (WNK) – STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) – Cation-Coupled Cl–Cotransporters (CCCs) cascade. Binding of a Cl– anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl– release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl– influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl– sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.
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Affiliation(s)
- Adrián Rafael Murillo-de-Ozores
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paola de Los Heros
- Unidad de Investigación UNAM-INC, Research Division, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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44
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Novel carbon film induces precocious calcium oscillation to promote neuronal cell maturation. Sci Rep 2020; 10:17661. [PMID: 33077786 PMCID: PMC7573613 DOI: 10.1038/s41598-020-74535-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/01/2020] [Indexed: 11/09/2022] Open
Abstract
Different types of carbon materials are biocompatible with neural cells and can promote maturation. The mechanism of this effect is not clear. Here we have tested the capacity of a carbon material composed of amorphous sp3 carbon backbone, embedded with a percolating network of sp2 carbon domains to sustain neuronal cultures. We found that cortical neurons survive and develop faster on this novel carbon material. After 3 days in culture, there is a precocious increase in the frequency of neuronal activity and in the expression of maturation marker KCC2 on carbon films as compared to a commonly used glass surface. Accelerated development is accompanied by a dramatic increase in neuronal dendrite arborization. The mechanism for the precocious maturation involves the activation of intracellular calcium oscillations by the carbon material already after 1 day in culture. Carbon-induced oscillations are independent of network activity and reflect intrinsic spontaneous activation of developing neurons. Thus, these results reveal a novel mechanism for carbon material-induced neuronal survival and maturation.
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45
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Kesaf S, Khirug S, Dinh E, Saez Garcia M, Soni S, Orav E, Delpire E, Taira T, Lauri SE, Rivera C. The Kainate Receptor Subunit GluK2 Interacts With KCC2 to Promote Maturation of Dendritic Spines. Front Cell Neurosci 2020; 14:252. [PMID: 33005130 PMCID: PMC7479265 DOI: 10.3389/fncel.2020.00252] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/22/2020] [Indexed: 12/25/2022] Open
Abstract
Kainate receptors (KAR) play a crucial role in the plasticity and functional maturation of glutamatergic synapses. However, how they regulate structural plasticity of dendritic spines is not known. The GluK2 subunit was recently shown to coexist in a functional complex with the neuronal K-Cl cotransporter KCC2. Apart from having a crucial role in the maturation of GABAergic transmission, KCC2 has a morphogenic role in the maturation of dendritic spines. Here, we show that in vivo local inactivation of GluK2 expression in CA3 hippocampal neurons induces altered morphology of dendritic spines and reduction in mEPSC frequency. GluK2 deficiency also resulted in a strong change in the subcellular distribution of KCC2 as well as a smaller somatodendritic gradient in the reversal potential of GABAA. Strikingly, the aberrant morphology of dendritic spines in GluK2-deficient CA3 pyramidal neurons was restored by overexpression of KCC2. GluK2 silencing in hippocampal neurons significantly reduced the expression of 4.1N and functional form of the actin filament severing protein cofilin. Consistently, assessment of actin dynamics using fluorescence recovery after photobleaching (FRAP) of β-actin showed a significant increase in the stability of F-actin filaments in dendritic spines. In conclusion, our results demonstrate that GluK2-KCC2 interaction plays an important role in the structural maturation of dendritic spines. This also provides novel insights into the connection between KAR dysfunction, structural plasticity, and developmental disorders.
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Affiliation(s)
- Sebnem Kesaf
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Stanislav Khirug
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Emilie Dinh
- Developmental Biology Institute of Marseille, Marseille, France
| | - Marta Saez Garcia
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Shetal Soni
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Ester Orav
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Tomi Taira
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sari E Lauri
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Claudio Rivera
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Institut de Neurobiologie de la Méditerranée (INMED) UMR901, Marseille, France
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46
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Wirth MJ, Ackels T, Kriebel A, Kriebel K, Mey J, Kuenzel T, Wagner H. Expression patterns of chloride transporters in the auditory brainstem of developing chicken. Hear Res 2020; 393:108013. [PMID: 32554128 DOI: 10.1016/j.heares.2020.108013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 04/29/2020] [Accepted: 05/29/2020] [Indexed: 01/23/2023]
Abstract
GABAergic transmission changes from depolarization to hyperpolarization in most vertebrate brain regions during development. By contrast, in the auditory brainstem of chicken a depolarizing effect of GABA persists after hatching. Since auditory brainstem neurons that receive GABAergic input have a Cl- reversal potential above resting membrane potential, a specifically tuned activity of Cl- transporters is likely. We here present a developmental study of the expression patterns of several members of the SLC12 family (NKCC1, NKCC2, KCC1, KCC2, KCC4, CCC6, CCC9) and of AE3 at developmental ages E7, E10, E12, E15, E17, and P1 with quantitative RT-PCR. NKCC2 and CCC9 were not detected in auditory brainstem (positive control: kidney). KCC1, CCC6 and AE3 were expressed, but not regulated, while NKCC1, KCC2 and KCC4 were regulated. The expression of the latter transporters increased, with KCC2 exhibiting the strongest expression at all time points. Biochemical analysis of the protein expression of NKCC1, KCC2 and KCC4 corroborated the findings on the mRNA level. All three transporters showed a localization at the outer rim of the cells, with NKCC1 and KCC2 expressed in neurons, and KCC4 predominantly in glia. The comparison of the published chloride reversal potential and expression of transporter proteins suggest strong differences in the efficiency of the three transporters. Further, the strong KCC2 expression could reflect a role in the structural development of auditory brainstem synapses that might lead to changes in the physiological properties.
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Affiliation(s)
- Marcus J Wirth
- Department for Chemosensation, RWTH Aachen University, Aachen, Germany.
| | - Tobias Ackels
- Neurophysiology of Behaviour Lab, The Francis Crick Institute, London, United Kingdom; Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Andreas Kriebel
- Department for Zoology and Animal Physiology, RWTH Aachen University, Aachen, Germany
| | - Katharina Kriebel
- Department for Zoology and Animal Physiology, RWTH Aachen University, Aachen, Germany
| | - Jörg Mey
- Department for Chemosensation, RWTH Aachen University, Aachen, Germany; Hospital Nacional de Parapléjicos, Toledo, Spain
| | - Thomas Kuenzel
- Department for Chemosensation, RWTH Aachen University, Aachen, Germany
| | - Hermann Wagner
- Department for Zoology and Animal Physiology, RWTH Aachen University, Aachen, Germany
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47
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Duy PQ, He M, He Z, Kahle KT. Preclinical insights into therapeutic targeting of KCC2 for disorders of neuronal hyperexcitability. Expert Opin Ther Targets 2020; 24:629-637. [PMID: 32336175 DOI: 10.1080/14728222.2020.1762174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Epilepsy is a common neurological disorder of neuronal hyperexcitability that begets recurrent and unprovoked seizures. The lack of a truly satisfactory pharmacotherapy for epilepsy highlights the clinical urgency for the discovery of new drug targets. To that end, targeting the electroneutral K+/Cl- cotransporter KCC2 has emerged as a novel therapeutic strategy for the treatment of epilepsy. AREAS COVERED We summarize the roles of KCC2 in the maintenance of synaptic inhibition and the evidence linking KCC2 dysfunction to epileptogenesis. We also discuss preclinical proof-of-principle studies that demonstrate that augmentation of KCC2 function can reduce seizure activity. Moreover, potential strategies to modulate KCC2 activity for therapeutic benefit are highlighted. EXPERT OPINION Although KCC2 is a promising drug target, questions remain before clinical translation. It is unclear whether increasing KCC2 activity can reverse epileptogenesis, the ultimate curative goal for epilepsy therapy that extends beyond seizure reduction. Furthermore, the potential adverse effects associated with increased KCC2 function have not been studied. Continued investigations into the neurobiology of KCC2 will help to translate promising preclinical insights into viable therapeutic avenues that leverage fundamental properties of KCC2 to treat medically intractable epilepsy and other disorders of failed synaptic inhibition with attendant neuronal hyperexcitability.
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Affiliation(s)
- Phan Q Duy
- Department of Neurosurgery, Yale University School of Medicine , New Haven, CT, USA.,Medical Scientist Training Program, Yale University School of Medicine , New Haven, CT, USA
| | - Miao He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School , Boston, MA, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School , Boston, MA, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Yale University School of Medicine , New Haven, CT, USA.,Department of Genetics, Yale University School of Medicine , New Haven, CT, USA.,Departments of Pediatrics and Cellular & Molecular Physiology, Yale University School of Medicine , New Haven, CT, USA.,Yale-Rockefeller NIH Centers for Mendelian Genomics, Yale University , New Haven, CT, USA.,Yale Stem Cell Center, Yale School of Medicine , New Haven, CT, USA
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48
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Mi TW, Sun XW, Wang ZM, Wang YY, He XC, Liu C, Zhang SF, Du HZ, Liu CM, Teng ZQ. Loss of MicroRNA-137 Impairs the Homeostasis of Potassium in Neurons via KCC2. Exp Neurobiol 2020; 29:138-149. [PMID: 32408404 PMCID: PMC7237267 DOI: 10.5607/en19072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
Neuropsychiatric disorders are the leading cause of mental and intellectual disabilities worldwide. Current therapies against neuropsychiatric disorders are very limited, and very little is known about the onset and development of these diseases, and their most effective treatments. MIR137 has been previously identified as a risk gene for the etiology of schizophrenia, bipolar disorder, and autism spectrum disorder. Here we generated a forebrain-specific MIR137 knockout mouse model, and provided evidence that loss of miR-137 resulted in impaired homeostasis of potassium in mouse hippocampal neurons. KCC2, a potassium-chloride co-transporter, was a direct downstream target of miR-137. The KCC2 specific antagonist VU0240551 could balance the current of potassium in miR-137 knockout neurons, and knockdown of KCC2 could ameliorate anxiety-like behavior in MIR137 cKO mice. These data suggest that KCC2 antagonists or knockdown might be beneficial to neuropsychiatric disorders due to the deficiency of miR-137.
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Affiliation(s)
- Ting-Wei Mi
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiao-Wen Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi-Meng Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying-Ying Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuan-Cheng He
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Cong Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuang-Feng Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,School of Life Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Hong-Zhen Du
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Chang-Mei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhao-Qian Teng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
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49
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Salmon CK, Pribiag H, Gizowski C, Farmer WT, Cameron S, Jones EV, Mahadevan V, Bourque CW, Stellwagen D, Woodin MA, Murai KK. Depolarizing GABA Transmission Restrains Activity-Dependent Glutamatergic Synapse Formation in the Developing Hippocampal Circuit. Front Cell Neurosci 2020; 14:36. [PMID: 32161521 PMCID: PMC7053538 DOI: 10.3389/fncel.2020.00036] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 02/05/2020] [Indexed: 12/27/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the mature brain but has the paradoxical property of depolarizing neurons during early development. Depolarization provided by GABAA transmission during this early phase regulates neural stem cell proliferation, neural migration, neurite outgrowth, synapse formation, and circuit refinement, making GABA a key factor in neural circuit development. Importantly, depending on the context, depolarizing GABAA transmission can either drive neural activity or inhibit it through shunting inhibition. The varying roles of depolarizing GABAA transmission during development, and its ability to both drive and inhibit neural activity, makes it a difficult developmental cue to study. This is particularly true in the later stages of development when the majority of synapses form and GABAA transmission switches from depolarizing to hyperpolarizing. Here, we addressed the importance of depolarizing but inhibitory (or shunting) GABAA transmission in glutamatergic synapse formation in hippocampal CA1 pyramidal neurons. We first showed that the developmental depolarizing-to-hyperpolarizing switch in GABAA transmission is recapitulated in organotypic hippocampal slice cultures. Based on the expression profile of K+−Cl− co-transporter 2 (KCC2) and changes in the GABA reversal potential, we pinpointed the timing of the switch from depolarizing to hyperpolarizing GABAA transmission in CA1 neurons. We found that blocking depolarizing but shunting GABAA transmission increased excitatory synapse number and strength, indicating that depolarizing GABAA transmission can restrain glutamatergic synapse formation. The increase in glutamatergic synapses was activity-dependent but independent of BDNF signaling. Importantly, the elevated number of synapses was stable for more than a week after GABAA inhibitors were washed out. Together these findings point to the ability of immature GABAergic transmission to restrain glutamatergic synapse formation and suggest an unexpected role for depolarizing GABAA transmission in shaping excitatory connectivity during neural circuit development.
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Affiliation(s)
- Christopher K Salmon
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Horia Pribiag
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Claire Gizowski
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - W Todd Farmer
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Scott Cameron
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Emma V Jones
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Vivek Mahadevan
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - David Stellwagen
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Melanie A Woodin
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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50
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Mavrovic M, Uvarov P, Delpire E, Vutskits L, Kaila K, Puskarjov M. Loss of non-canonical KCC2 functions promotes developmental apoptosis of cortical projection neurons. EMBO Rep 2020; 21:e48880. [PMID: 32064760 DOI: 10.15252/embr.201948880] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/16/2020] [Accepted: 01/24/2020] [Indexed: 01/01/2023] Open
Abstract
KCC2, encoded in humans by the SLC12A5 gene, is a multifunctional neuron-specific protein initially identified as the chloride (Cl- ) extruder critical for hyperpolarizing GABAA receptor currents. Independently of its canonical function as a K-Cl cotransporter, KCC2 regulates the actin cytoskeleton via molecular interactions mediated through its large intracellular C-terminal domain (CTD). Contrary to the common assumption that embryonic neocortical projection neurons express KCC2 at non-significant levels, here we show that loss of KCC2 enhances apoptosis of late-born upper-layer cortical projection neurons in the embryonic brain. In utero electroporation of plasmids encoding truncated, transport-dead KCC2 constructs retaining the CTD was as efficient as of that encoding full-length KCC2 in preventing elimination of migrating projection neurons upon conditional deletion of KCC2. This was in contrast to the effect of a full-length KCC2 construct bearing a CTD missense mutation (KCC2R952H ), which disrupts cytoskeletal interactions and has been found in patients with neurological and psychiatric disorders, notably seizures and epilepsy. Together, our findings indicate ion transport-independent, CTD-mediated regulation of developmental apoptosis by KCC2 in migrating cortical projection neurons.
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Affiliation(s)
- Martina Mavrovic
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Pavel Uvarov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University, Nashville, TN, USA
| | - Laszlo Vutskits
- Department of Basic Neurosciences, University of Geneva Medical School, Geneva 4, Switzerland.,Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva, Geneva 4, Switzerland
| | - Kai Kaila
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Martin Puskarjov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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