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He YY, Luo S, Jin L, Wang PY, Xu J, Jiao HL, Yan HJ, Wang Y, Zhai QX, Ji JJ, Zhang WJ, Zhou P, Li H, Liao WP, Lan S, Xu L. DLG3 variants caused X-linked epilepsy with/without neurodevelopmental disorders and the genotype-phenotype correlation. Front Mol Neurosci 2024; 16:1290919. [PMID: 38249294 PMCID: PMC10796462 DOI: 10.3389/fnmol.2023.1290919] [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: 10/11/2023] [Accepted: 11/28/2023] [Indexed: 01/23/2024] Open
Abstract
Background The DLG3 gene encodes disks large membrane-associated guanylate kinase scaffold protein 3, which plays essential roles in the clustering of N-methyl-D-aspartate receptors (NMDARs) at excitatory synapses. Previously, DLG3 has been identified as the causative gene of X-linked intellectual developmental disorder-90 (XLID-90; OMIM# 300850). This study aims to explore the phenotypic spectrum of DLG3 and the genotype-phenotype correlation. Methods Trios-based whole-exome sequencing was performed in patients with epilepsy of unknown causes. To analyze the genotype-phenotype correlations, previously reported DLG3 variants were systematically reviewed. Results DLG3 variants were identified in seven unrelated cases with epilepsy. These variants had no hemizygous frequencies in controls. All variants were predicted to be damaging by silico tools and alter the hydrogen bonds with surrounding residues and/or protein stability. Four cases mainly presented with generalized seizures, including generalized tonic-clonic and myoclonic seizures, and the other three cases exhibited secondary generalized tonic-clonic seizures and focal seizures. Multifocal discharges were recorded in all cases during electroencephalography monitoring, including the four cases with generalized discharges initially but multifocal discharges after drug treating. Protein-protein interaction network analysis revealed that DLG3 interacts with 52 genes with high confidence, in which the majority of disease-causing genes were associated with a wide spectrum of neurodevelopmental disorder (NDD) and epilepsy. Three patients with variants locating outside functional domains all achieved seizure-free, while the four patients with variants locating in functional domains presented poor control of seizures. Analysis of previously reported cases revealed that patients with non-null variants presented higher percentages of epilepsy than those with null variants, suggesting a genotype-phenotype correlation. Significance This study suggested that DLG3 variants were associated with epilepsy with/without NDD, expanding the phenotypic spectrum of DLG3. The observed genotype-phenotype correlation potentially contributes to the understanding of the underlying mechanisms driving phenotypic variation.
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Affiliation(s)
- Yun-Yan He
- Department of Neurology, Women and Children’s Hospital, Qingdao University, Qingdao, China
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Sheng Luo
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Liang Jin
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- Department of Neurology, The Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Peng-Yu Wang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Jie Xu
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hong-Liang Jiao
- Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hong-Jun Yan
- Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Yao Wang
- Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Qiong-Xiang Zhai
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Jing-Jing Ji
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Weng-Jun Zhang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Peng Zhou
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hua Li
- Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Wei-Ping Liao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Song Lan
- Department of Neurology, Maoming People’s Hospital, Maoming, China
| | - Lin Xu
- Department of Neurology, Women and Children’s Hospital, Qingdao University, Qingdao, China
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McMoneagle E, Zhou J, Zhang S, Huang W, Josiah SS, Ding K, Wang Y, Zhang J. Neuronal K +-Cl - cotransporter KCC2 as a promising drug target for epilepsy treatment. Acta Pharmacol Sin 2024; 45:1-22. [PMID: 37704745 PMCID: PMC10770335 DOI: 10.1038/s41401-023-01149-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/02/2023] [Indexed: 09/14/2023] Open
Abstract
Epilepsy is a prevalent neurological disorder characterized by unprovoked seizures. γ-Aminobutyric acid (GABA) serves as the primary fast inhibitory neurotransmitter in the brain, and GABA binding to the GABAA receptor (GABAAR) regulates Cl- and bicarbonate (HCO3-) influx or efflux through the channel pore, leading to GABAergic inhibition or excitation, respectively. The neuron-specific K+-Cl- cotransporter 2 (KCC2) is essential for maintaining a low intracellular Cl- concentration, ensuring GABAAR-mediated inhibition. Impaired KCC2 function results in GABAergic excitation associated with epileptic activity. Loss-of-function mutations and altered expression of KCC2 lead to elevated [Cl-]i and compromised synaptic inhibition, contributing to epilepsy pathogenesis in human patients. KCC2 antagonism studies demonstrate the necessity of limiting neuronal hyperexcitability within the brain, as reduced KCC2 functioning leads to seizure activity. Strategies focusing on direct (enhancing KCC2 activation) and indirect KCC2 modulation (altering KCC2 phosphorylation and transcription) have proven effective in attenuating seizure severity and exhibiting anti-convulsant properties. These findings highlight KCC2 as a promising therapeutic target for treating epilepsy. Recent advances in understanding KCC2 regulatory mechanisms, particularly via signaling pathways such as WNK, PKC, BDNF, and its receptor TrkB, have led to the discovery of novel small molecules that modulate KCC2. Inhibiting WNK kinase or utilizing newly discovered KCC2 agonists has demonstrated KCC2 activation and seizure attenuation in animal models. This review discusses the role of KCC2 in epilepsy and evaluates its potential as a drug target for epilepsy treatment by exploring various strategies to regulate KCC2 activity.
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Affiliation(s)
- Erin McMoneagle
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Jin Zhou
- 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
| | - Shiyao Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China
| | - Weixue Huang
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sunday Solomon Josiah
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Ke Ding
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 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.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK.
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China.
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
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Radulovic T, Rajaram E, Ebbers L, Pagella S, Winklhofer M, Kopp-Scheinpflug C, Nothwang HG, Milenkovic I, Hartmann AM. Serine 937 phosphorylation enhances KCC2 activity and strengthens synaptic inhibition. Sci Rep 2023; 13:21660. [PMID: 38066086 PMCID: PMC10709408 DOI: 10.1038/s41598-023-48884-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
The potassium chloride cotransporter KCC2 is crucial for Cl- extrusion from mature neurons and thus key to hyperpolarizing inhibition. Auditory brainstem circuits contain well-understood inhibitory projections and provide a potent model to study the regulation of synaptic inhibition. Two peculiarities of the auditory brainstem are (i) posttranslational activation of KCC2 during development and (ii) extremely negative reversal potentials in specific circuits. To investigate the role of the potent phospho-site serine 937 therein, we generated a KCC2 Thr934Ala/Ser937Asp double mutation, in which Ser937 is replaced by aspartate mimicking the phosphorylated state, and the neighbouring Thr934 arrested in the dephosphorylated state. This double mutant showed a twofold increased transport activity in HEK293 cells, raising the hypothesis that auditory brainstem neurons show lower [Cl-]i. and increased glycinergic inhibition. This was tested in a mouse model carrying the same KCC2 Thr934Ala/Ser937Asp mutation by the use of the CRISPR/Cas9 technology. Homozygous KCC2 Thr934Ala/Ser937Asp mice showed an earlier developmental onset of hyperpolarisation in the auditory brainstem. Mature neurons displayed stronger glycinergic inhibition due to hyperpolarized ECl-. These data demonstrate that phospho-regulation of KCC2 Ser937 is a potent way to interfere with the excitation-inhibition balance in neural circuits.
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Affiliation(s)
- Tamara Radulovic
- Division of Physiology School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Research Center Neurosensory Science, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Ezhilarasan Rajaram
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Lena Ebbers
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Sara Pagella
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Michael Winklhofer
- Research Center Neurosensory Science, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Institute for Biology and Environmental Sciences IBU, Carl Von Ossietzky University of Oldenburg, 26111, Oldenburg, Germany
| | - Conny Kopp-Scheinpflug
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Hans Gerd Nothwang
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Research Center Neurosensory Science, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Center of Excellence Hearing4all, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Ivan Milenkovic
- Division of Physiology School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Research Center Neurosensory Science, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Anna-Maria Hartmann
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
- Research Center Neurosensory Science, Carl Von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
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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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Yakovlev AV, Kurmashova E, Gataulina E, Gerasimova E, Khalilov I, Sitdikova GF. Maternal hyperhomocysteinemia increases seizures susceptibility of neonatal rats. Life Sci 2023; 329:121953. [PMID: 37467884 DOI: 10.1016/j.lfs.2023.121953] [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: 05/26/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023]
Abstract
AIMS Neonatal seizures are severe pathologies which may result in long-term neurological consequences. High plasma concentrations of homocysteine - hyperhomocysteinemia (hHCy) - are associated with epilepsy. In the present study, we evaluated susceptibility to seizure of neonatal rats with prenatal hHCy. MAIN METHODS Prenatal hHCy was induced by feeding females with a high-methionine diet. Experiments were performed on pups during the first three postnatal weeks. Flurothyl-induced epileptic behavior was assessed according to Racine's scale. Epileptiform activity in the hippocampus was recorded using electrophysiological methods. The balance of excitation/inhibition, functional GABAergic inhibition and GABA reversal potential in hippocampal neurons were analyzed. KEY FINDINGS Rats with hHCy developed more severe stages of behavioral patterns during flurothyl-induced epilepsy with shorter latency. Electrophysiological recordings demonstrated higher background neuronal activity in rats with hHCy. Seizure-like events triggered by flurothyl (in vivo) or 4-aminopyridine (in vitro) showed shorter latency, higher power and amplitude. An increased glutamate/GABA synaptic ratio was shown in the pyramidal neurons of rats with hHCy and more slices demonstrated excitation by isoguvacine, a selective GABA(A) receptor agonist, during the first and second postnatal weeks. The GABA driving force and the reversal potential of GABA(A) currents were more positive during the second postnatal week for hHCy rats. SIGNIFICANCE The higher susceptibility to seizures in rats with prenatal hHCy due to a shift in the balance of excitation/inhibition toward excitation may underlie the clinical evidence about the association of hHCy with an increased risk of epilepsy.
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Affiliation(s)
- A V Yakovlev
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia.
| | - E Kurmashova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gataulina
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gerasimova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - I Khalilov
- Institut de Neurobiologie de la Méditerranée, INMED UMR901 Parc scientifique de Luminy, 163 avenue de Luminy BP13 - 13273, Marseille cedex 09, France; Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - G F Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
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van van Hugte EJH, Schubert D, Nadif Kasri N. Excitatory/inhibitory balance in epilepsies and neurodevelopmental disorders: Depolarizing γ-aminobutyric acid as a common mechanism. Epilepsia 2023; 64:1975-1990. [PMID: 37195166 DOI: 10.1111/epi.17651] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023]
Abstract
Epilepsy is one of the most common neurological disorders. Although many factors contribute to epileptogenesis, seizure generation is mostly linked to hyperexcitability due to alterations in excitatory/inhibitory (E/I) balance. The common hypothesis is that reduced inhibition, increased excitation, or both contribute to the etiology of epilepsy. Increasing evidence shows that this view is oversimplistic, and that increased inhibition through depolarizing γ-aminobutyric acid (GABA) similarly contributes to epileptogenisis. In early development, GABA signaling is depolarizing, inducing outward Cl- currents due to high intracellular Cl- concentrations. During maturation, the mechanisms of GABA action shift from depolarizing to hyperpolarizing, a critical event during brain development. Altered timing of this shift is associated with both neurodevelopmental disorders and epilepsy. Here, we consider the different ways that depolarizing GABA contributes to altered E/I balance and epileptogenesis, and discuss that alterations in depolarizing GABA could be a common denominator underlying seizure generation in neurodevelopmental disorders and epilepsies.
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Affiliation(s)
- Eline J H van van Hugte
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
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7
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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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8
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Fogarty MJ. Inhibitory Synaptic Influences on Developmental Motor Disorders. Int J Mol Sci 2023; 24:ijms24086962. [PMID: 37108127 PMCID: PMC10138861 DOI: 10.3390/ijms24086962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
During development, GABA and glycine play major trophic and synaptic roles in the establishment of the neuromotor system. In this review, we summarise the formation, function and maturation of GABAergic and glycinergic synapses within neuromotor circuits during development. We take special care to discuss the differences in limb and respiratory neuromotor control. We then investigate the influences that GABAergic and glycinergic neurotransmission has on two major developmental neuromotor disorders: Rett syndrome and spastic cerebral palsy. We present these two syndromes in order to contrast the approaches to disease mechanism and therapy. While both conditions have motor dysfunctions at their core, one condition Rett syndrome, despite having myriad symptoms, has scientists focused on the breathing abnormalities and their alleviation-to great clinical advances. By contrast, cerebral palsy remains a scientific quagmire or poor definitions, no widely adopted model and a lack of therapeutic focus. We conclude that the sheer abundance of diversity of inhibitory neurotransmitter targets should provide hope for intractable conditions, particularly those that exhibit broad spectra of dysfunction-such as spastic cerebral palsy and Rett syndrome.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
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Kreis A, Issa F, Yerna X, Jabbour C, Schakman O, de Clippele M, Tajeddine N, Pierrot N, Octave JN, Gualdani R, Gailly P. Conditional deletion of KCC2 impairs synaptic plasticity and both spatial and nonspatial memory. Front Mol Neurosci 2023; 16:1081657. [PMID: 37168681 PMCID: PMC10164999 DOI: 10.3389/fnmol.2023.1081657] [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: 10/27/2022] [Accepted: 03/31/2023] [Indexed: 05/13/2023] Open
Abstract
The postsynaptic inhibition through GABAA receptors (GABAAR) relies on two mechanisms, a shunting effect due to an increase in the postsynaptic membrane conductance and, in mature neurons, a hyperpolarization effect due to an entry of chloride into postsynaptic neurons. The second effect requires the action of the K+-Cl- cotransporter KCC2 which extrudes Cl- from the cell and maintains its cytosolic concentration very low. Neuronal chloride equilibrium seems to be dysregulated in several neurological and psychiatric conditions such as epilepsy, anxiety, schizophrenia, Down syndrome, or Alzheimer's disease. In the present study, we used the KCC2 Cre-lox knockdown system to investigate the role of KCC2 in synaptic plasticity and memory formation in adult mice. Tamoxifen-induced conditional deletion of KCC2 in glutamatergic neurons of the forebrain was performed at 3 months of age and resulted in spatial and nonspatial learning impairment. On brain slices, the stimulation of Schaffer collaterals by a theta burst induced long-term potentiation (LTP). The lack of KCC2 did not affect potentiation of field excitatory postsynaptic potentials (fEPSP) measured in the stratum radiatum (dendrites) but increased population spike (PS) amplitudes measured in the CA1 somatic layer, suggesting a reinforcement of the EPSP-PS potentiation, i.e., an increased ability of EPSPs to generate action potentials. At the cellular level, KCC2 deletion induced a positive shift in the reversal potential of GABAAR-driven Cl- currents (EGABA), suggesting an intracellular accumulation of chloride subsequent to the downregulation of KCC2. After treatment with bumetanide, an antagonist of the Na+-K+-Cl- cotransporter NKCC1, spatial memory impairment, chloride accumulation, and EPSP-PS potentiation were rescued in mice lacking KCC2. The presented results emphasize the importance of chloride equilibrium and GABA-inhibiting ability in synaptic plasticity and memory formation.
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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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11
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Liu R, Xing Y, Zhang H, Wang J, Lai H, Cheng L, Li D, Yu T, Yan X, Xu C, Piao Y, Zeng L, Loh HH, Zhang G, Yang X. Imbalance between the function of Na+-K+-2Cl and K+-Cl impairs Cl– homeostasis in human focal cortical dysplasia. Front Mol Neurosci 2022; 15:954167. [PMID: 36324524 PMCID: PMC9621392 DOI: 10.3389/fnmol.2022.954167] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/27/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Altered expression patterns of Na+-K+-2Cl– (NKCC1) and K+-Cl– (KCC2) co-transporters have been implicated in the pathogenesis of epilepsy. Here, we assessed the effects of imbalanced NKCC1 and KCC2 on γ-aminobutyric acidergic (GABAergic) neurotransmission in certain brain regions involved in human focal cortical dysplasia (FCD). Materials and methods We sought to map a micro-macro neuronal network to better understand the epileptogenesis mechanism. In patients with FCD, we resected cortical tissue from the seizure the onset zone (SOZ) and the non-seizure onset zone (non-SOZ) inside the epileptogenic zone (EZ). Additionally, we resected non-epileptic neocortical tissue from the patients with mesial temporal lobe epilepsy (MTLE) as control. All of tissues were analyzed using perforated patch recordings. NKCC1 and KCC2 co-transporters expression and distribution were analyzed by immunohistochemistry and western blotting. Results Results revealed that depolarized GABAergic signals were observed in pyramidal neurons in the SOZ and non-SOZ groups compared with the control group. The total number of pyramidal neurons showing GABAergic spontaneous postsynaptic currents was 11/14, 7/17, and 0/12 in the SOZ, non-SOZ, and control groups, respectively. The depolarizing GABAergic response was significantly dampened by the specific NKCC1 inhibitor bumetanide (BUM). Patients with FCD exhibited higher expression and internalized distribution of KCC2, particularly in the SOZ group. Conclusion Our results provide evidence of a potential neurocircuit underpinning SOZ epileptogenesis and non-SOZ seizure susceptibility. Imbalanced function of NKCC1 and KCC2 may affect chloride ion homeostasis in neurons and alter GABAergic inhibitory action, thereby contributing to epileptogenesis in FCDs. Maintaining chloride ion homeostasis in the neurons may represent a new avenue for the development of novel anti-seizure medications (ASMs).
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Affiliation(s)
- Ru Liu
- Guangzhou Laboratory, Guangzhou, China
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yue Xing
- Guangzhou Laboratory, Guangzhou, China
| | | | - Junling Wang
- Guangzhou Laboratory, Guangzhou, China
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | | | - Lipeng Cheng
- Guangzhou Laboratory, Guangzhou, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Donghong Li
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Tao Yu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaoming Yan
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Cuiping Xu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Linghui Zeng
- Department of Pharmacology, Zhejiang University City College, Hangzhou, China
| | | | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- *Correspondence: Guojun Zhang,
| | - Xiaofeng Yang
- Guangzhou Laboratory, Guangzhou, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
- Xiaofeng Yang,
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Delpire E, Ben-Ari Y. A Wholistic View of How Bumetanide Attenuates Autism Spectrum Disorders. Cells 2022; 11:cells11152419. [PMID: 35954263 PMCID: PMC9367773 DOI: 10.3390/cells11152419] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/22/2022] [Accepted: 08/03/2022] [Indexed: 01/27/2023] Open
Abstract
The specific NKCC1 cotransporter antagonist, bumetanide, attenuates the severity of Autism Spectrum Disorders (ASD), and many neurodevelopmental or neurodegenerative disorders in animal models and clinical trials. However, the pervasive expression of NKCC1 in many cell types throughout the body is thought to challenge the therapeutic efficacy of bumetanide. However, many peripheral functions, including intestinal, metabolic, or vascular, etc., are perturbed in brain disorders contributing to the neurological sequels. Alterations of these functions also increase the incidence of the disorder suggesting complex bidirectional links with the clinical manifestations. We suggest that a more holistic view of ASD and other disorders is warranted to account for the multiple sites impacted by the original intra-uterine insult. From this perspective, large-spectrum active repositioned drugs that act centrally and peripherally might constitute a useful approach to treating these disorders.
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Affiliation(s)
- Eric Delpire
- Departments of Anesthesiology and Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Correspondence:
| | - Yehezkel Ben-Ari
- NeuroChlore, Campus Scientifique de Luminy, 163 Route de Luminy, 13273 Marseilles, France
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13
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Hartmann AM, Nothwang HG. NKCC1 and KCC2: Structural insights into phospho-regulation. Front Mol Neurosci 2022; 15:964488. [PMID: 35935337 PMCID: PMC9355526 DOI: 10.3389/fnmol.2022.964488] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
Inhibitory neurotransmission plays a fundamental role in the central nervous system, with about 30–50% of synaptic connections being inhibitory. The action of both inhibitory neurotransmitter, gamma-aminobutyric-acid (GABA) and glycine, mainly relies on the intracellular Cl– concentration in neurons. This is set by the interplay of the cation chloride cotransporters NKCC1 (Na+, K+, Cl– cotransporter), a main Cl– uptake transporter, and KCC2 (K+, Cl– cotransporter), the principle Cl– extruder in neurons. Accordingly, their dysfunction is associated with severe neurological, psychiatric, and neurodegenerative disorders. This has triggered great interest in understanding their regulation, with a strong focus on phosphorylation. Recent structural data by cryogenic electron microscopy provide the unique possibility to gain insight into the action of these phosphorylations. Interestingly, in KCC2, six out of ten (60%) known regulatory phospho-sites reside within a region of 134 amino acid residues (12% of the total residues) between helices α8 and α9 that lacks fixed or ordered three-dimensional structures. It thus represents a so-called intrinsically disordered region. Two further phospho-sites, Tyr903 and Thr906, are also located in a disordered region between the ß8 strand and the α8 helix. We make the case that especially the disordered region between helices α8 and α9 acts as a platform to integrate different signaling pathways and simultaneously constitute a flexible, highly dynamic linker that can survey a wide variety of distinct conformations. As each conformation can have distinct binding affinities and specificity properties, this enables regulation of [Cl–]i and thus the ionic driving force in a history-dependent way. This region might thus act as a molecular processor underlying the well described phenomenon of ionic plasticity that has been ascribed to inhibitory neurotransmission. Finally, it might explain the stunning long-range effects of mutations on phospho-sites in KCC2.
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Affiliation(s)
- Anna-Maria Hartmann
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- *Correspondence: Anna-Maria Hartmann,
| | - Hans Gerd Nothwang
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Center of Excellence Hearing4all, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the “dematuration” of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
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Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
- *Correspondence: Kelvin K. Hui,
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Thomas E. Chater,
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
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15
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Liedtke W. Long March Toward Safe and Effective Analgesia by Enhancing Gene Expression of Kcc2: First Steps Taken. Front Mol Neurosci 2022; 15:865600. [PMID: 35645734 PMCID: PMC9137411 DOI: 10.3389/fnmol.2022.865600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/08/2022] [Indexed: 11/15/2022] Open
Abstract
Low intraneuronal chloride in spinal cord dorsal horn pain relay neurons is critical for physiologic transmission of primary pain afferents because low intraneuronal chloride dictates whether GABA-ergic and glycin-ergic neurotransmission is inhibitory. If the neuronal chloride elevates to pathologic levels, then spinal cord primary pain relay becomes leaky and exhibits the behavioral hallmarks of pathologic pain, namely hypersensitivity and allodynia. Low chloride in spinal cord dorsal horn neurons is maintained by proper gene expression of Kcc2 and sustained physiologic function of the KCC2 chloride extruding electroneutral transporter. Peripheral nerve injury and other forms of neural injury evoke greatly diminished Kcc2 gene expression and subsequent corruption of inhibitory neurotransmission in the spinal cord dorsal horn, thus causing derailment of the gate function for pain. Here I review key discoveries that have helped us understand these fundamentals, and focus on recent insights relating to the discovery of Kcc2 gene expression enhancing compounds via compound screens in neurons. One such study characterized the kinase inhibitor, kenpaullone, more in-depth, revealing its function as a robust and long-lasting analgesic in preclinical models of nerve injury and cancer bone pain, also elucidating its mechanism of action via GSK3β inhibition, diminishing delta-catenin phosphorylation, and facilitating its nuclear transfer and subsequent enhancement of Kcc2 gene expression by de-repressing Kaiso epigenetic transcriptional regulator. Future directions re Kcc2 gene expression enhancement are discussed, namely combination with other analgesics and analgesic methods, such as spinal cord stimulation and electroacupuncture, gene therapy, and leveraging Kcc2 gene expression-enhancing nanomaterials.
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16
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Postnatal GABAA Receptor Activation Alters Synaptic Plasticity and Cognition in Adult Wistar Rats. Mol Neurobiol 2022; 59:3585-3599. [DOI: 10.1007/s12035-022-02805-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
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17
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Systemic LPS-induced microglial activation results in increased GABAergic tone: A mechanism of protection against neuroinflammation in the medial prefrontal cortex in mice. Brain Behav Immun 2022; 99:53-69. [PMID: 34582995 DOI: 10.1016/j.bbi.2021.09.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/19/2021] [Accepted: 09/21/2021] [Indexed: 02/01/2023] Open
Abstract
Neuroinflammation with excess microglial activation and synaptic dysfunction are early symptoms of most neurological diseases. However, how microglia-associated neuroinflammation regulates synaptic activity remains obscure. We report here that acute neuroinflammation induced by intraperitoneal injection of lipopolysaccharide (LPS) results in cell-type-specific increases in inhibitory postsynaptic currents in the glutamatergic, but not the GABAergic, neurons of medial prefrontal cortex (mPFC), coinciding with excessive microglial activation. LPS causes upregulation in levels of GABAAR subunits, glutamine synthetase and vesicular GABA transporter, and downregulation in brain-derived neurotrophic factor (BDNF) and its receptor, pTrkB. Blockage of microglial activation by minocycline ameliorates LPS-induced abnormal expression of GABA signaling-related proteins and activity of synaptic and network. Moreover, minocycline prevents the mice from LPS-induced aberrant behavior, such as a reduction in total distance and time spent in the centre in the open field test; decreases in entries into the open arm of elevated-plus maze and in consumption of sucrose; increased immobility in the tail suspension test. Furthermore, upregulation of GABA signaling by tiagabine also prevents LPS-induced microglial activation and aberrant behavior. This study illustrates a mode of bidirectional constitutive signaling between the neural and immune compartments of the brain, and suggests that the mPFC is an important area for brain-immune system communication. Moreover, the present study highlights GABAergic signaling as a key therapeutic target for mitigating neuroinflammation-induced abnormal synaptic activity in the mPFC, together with the associated behavioral abnormalities.
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18
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Hamze M, Medina I, Delmotte Q, Porcher C. Contribution of Smoothened Receptor Signaling in GABAergic Neurotransmission and Chloride Homeostasis in the Developing Rodent Brain. Front Physiol 2021; 12:798066. [PMID: 34955901 PMCID: PMC8703190 DOI: 10.3389/fphys.2021.798066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
In the early stages of the central nervous system growth and development, γ-aminobutyric acid (GABA) plays an instructive trophic role for key events including neurogenesis, migration, synaptogenesis, and network formation. These actions are associated with increased concentration of chloride ions in immature neurons [(Cl−)i] that determines the depolarizing strength of ion currents mediated by GABAA receptors, a ligand-gated Cl− permeable ion channel. During neuron maturation the (Cl−)i progressively decreases leading to weakening of GABA induced depolarization and enforcing GABA function as principal inhibitory neurotransmitter. A neuron restricted potassium-chloride co-transporter KCC2 is a key molecule governing Cl− extrusion and determining the resting level of (Cl−)i in developing and mature mammalian neurons. Among factors controlling the functioning of KCC2 and the maturation of inhibitory circuits, is Smoothened (Smo), the transducer in the receptor complex of the developmental protein Sonic Hedgehog (Shh). Too much or too little Shh-Smo action will have mirror effects on KCC2 stability at the neuron membrane, the GABA inhibitory strength, and ultimately on the newborn susceptibility to neurodevelopmental disorders. Both canonical and non-canonical Shh-Smo signal transduction pathways contribute to the regulation of KCC2 and GABAergic synaptic activity. In this review, we discuss the recent findings of the action of Shh-Smo signaling pathways on chloride ions homeostasis through the control of KCC2 membrane trafficking, and consequently on inhibitory neurotransmission and network activity during postnatal development.
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Affiliation(s)
- Mira Hamze
- Aix-Marseille University, INSERM, INMED, Parc Scientifique de Luminy, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité, Parc Scientifique de Luminy, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Igor Medina
- Aix-Marseille University, INSERM, INMED, Parc Scientifique de Luminy, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité, Parc Scientifique de Luminy, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Quentin Delmotte
- Aix-Marseille University, INSERM, INMED, Parc Scientifique de Luminy, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité, Parc Scientifique de Luminy, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Christophe Porcher
- Aix-Marseille University, INSERM, INMED, Parc Scientifique de Luminy, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité, Parc Scientifique de Luminy, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
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Bertoni A, Schaller F, Tyzio R, Gaillard S, Santini F, Xolin M, Diabira D, Vaidyanathan R, Matarazzo V, Medina I, Hammock E, Zhang J, Chini B, Gaiarsa JL, Muscatelli F. Oxytocin administration in neonates shapes hippocampal circuitry and restores social behavior in a mouse model of autism. Mol Psychiatry 2021; 26:7582-7595. [PMID: 34290367 PMCID: PMC8872977 DOI: 10.1038/s41380-021-01227-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 02/06/2023]
Abstract
Oxytocin is an important regulator of the social brain. In some animal models of autism, notably in Magel2tm1.1Mus-deficient mice, peripheral administration of oxytocin in infancy improves social behaviors until adulthood. However, neither the mechanisms responsible for social deficits nor the mechanisms by which such oxytocin administration has long-term effects are known. Here, we aimed to clarify these oxytocin-dependent mechanisms, focusing on social memory performance. Using in situ hybridization (RNAscope), we have established that Magel2 and oxytocin receptor are co-expressed in the dentate gyrus and CA2/CA3 hippocampal regions involved in the circuitry underlying social memory. Then, we have shown that Magel2tm1.1Mus-deficient mice, evaluated in a three-chamber test, present a deficit in social memory. Next, in hippocampus, we conducted neuroanatomical and functional studies using immunostaining, oxytocin-binding experiments, ex vivo electrophysiological recordings, calcium imaging and biochemical studies. We demonstrated: an increase of the GABAergic activity of CA3-pyramidal cells associated with an increase in the quantity of oxytocin receptors and of somatostatin interneurons in both DG and CA2/CA3 regions. We also revealed a delay in the GABAergic development sequence in Magel2tm1.1Mus-deficient pups, linked to phosphorylation modifications of KCC2. Above all, we demonstrated the positive effects of subcutaneous administration of oxytocin in the mutant neonates, restoring hippocampal alterations and social memory at adulthood. Although clinical trials are debated, this study highlights the mechanisms by which peripheral oxytocin administration in neonates impacts the brain and demonstrates the therapeutic value of oxytocin to treat infants with autism spectrum disorders.
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Affiliation(s)
- Alessandra Bertoni
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Fabienne Schaller
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Roman Tyzio
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Francesca Santini
- Institute of Neuroscience, National Research Council (CNR), Vedano al Lambro, Italy. Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Marion Xolin
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Diabé Diabira
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Valery Matarazzo
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Igor Medina
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, College of Medicine and Health, Hatherly Laboratories, University of Exeter, Exeter, UK
| | - Bice Chini
- Institute of Neuroscience, National Research Council (CNR), Vedano al Lambro, Italy. NeuroMI Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | - Jean-Luc Gaiarsa
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Françoise Muscatelli
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France.
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20
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Sullivan BJ, Kipnis PA, Carter BM, Shao LR, Kadam SD. Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model. Sci Signal 2021; 14:eabg2648. [PMID: 34752143 DOI: 10.1126/scisignal.abg2648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Brennan J Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Brandon M Carter
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Li-Rong Shao
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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21
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Portioli C, Ruiz Munevar MJ, De Vivo M, Cancedda L. Cation-coupled chloride cotransporters: chemical insights and disease implications. TRENDS IN CHEMISTRY 2021; 3:832-849. [PMID: 34604727 PMCID: PMC8461084 DOI: 10.1016/j.trechm.2021.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cation-coupled chloride cotransporters (CCCs) modulate the transport of sodium and/or potassium cations coupled with chloride anions across the cell membrane. CCCs thus help regulate intracellular ionic concentration and consequent cell volume homeostasis. This has been largely exploited in the past to develop diuretic drugs that act on CCCs expressed in the kidney. However, a growing wealth of evidence has demonstrated that CCCs are also critically involved in a great variety of other pathologies, motivating most recent drug discovery programs targeting CCCs. Here, we examine the structure–function relationship of CCCs. By linking recent high-resolution cryogenic electron microscopy (cryo-EM) data with older biochemical/functional studies on CCCs, we discuss the mechanistic insights and opportunities to design selective CCC modulators to treat diverse pathologies. The structural topology and function of all cation-coupled chloride cotransporters (CCCs) have been continuously investigated over the past 40 years, with great progress also thanks to the recent cryogenic electron microscopy (cryo-EM) resolution of the structures of five CCCs. In particular, such studies have clarified the structure–function relationship for the Na-K-Cl cotransporter NKCC1 and K-Cl cotransporters KCC1–4. The constantly growing evidence of the crucial involvement of CCCs in physiological and various pathological conditions, as well as the evidence of their wide expression in diverse body tissues, has promoted CCCs as targets for the discovery and development of new, safer, and more selective/effective drugs for a plethora of pathologies. Post-translational modification anchor points on the structure of CCCs may offer alternative strategies for small molecule drug discovery.
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Affiliation(s)
- Corinne Portioli
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy.,Laboratory of Molecular Modeling and Drug Discovery, IIT, Via Morego, 30 16163 Genoa, Italy
| | | | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, IIT, Via Morego, 30 16163 Genoa, Italy
| | - Laura Cancedda
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy.,Dulbecco Telethon Institute, Via Varese 16b, 00185 Rome, Italy
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22
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Chi G, Ebenhoch R, Man H, Tang H, Tremblay LE, Reggiano G, Qiu X, Bohstedt T, Liko I, Almeida FG, Garneau AP, Wang D, McKinley G, Moreau CP, Bountra KD, Abrusci P, Mukhopadhyay SMM, Fernandez‐Cid A, Slimani S, Lavoie JL, Burgess‐Brown NA, Tehan B, DiMaio F, Jazayeri A, Isenring P, Robinson CV, Dürr KL. Phospho-regulation, nucleotide binding and ion access control in potassium-chloride cotransporters. EMBO J 2021; 40:e107294. [PMID: 34031912 PMCID: PMC8280820 DOI: 10.15252/embj.2020107294] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/29/2021] [Accepted: 04/11/2021] [Indexed: 11/26/2022] Open
Abstract
Potassium-coupled chloride transporters (KCCs) play crucial roles in regulating cell volume and intracellular chloride concentration. They are characteristically inhibited under isotonic conditions via phospho-regulatory sites located within the cytoplasmic termini. Decreased inhibitory phosphorylation in response to hypotonic cell swelling stimulates transport activity, and dysfunction of this regulatory process has been associated with various human diseases. Here, we present cryo-EM structures of human KCC3b and KCC1, revealing structural determinants for phospho-regulation in both N- and C-termini. We show that phospho-mimetic KCC3b is arrested in an inward-facing state in which intracellular ion access is blocked by extensive contacts with the N-terminus. In another mutant with increased isotonic transport activity, KCC1Δ19, this interdomain interaction is absent, likely due to a unique phospho-regulatory site in the KCC1 N-terminus. Furthermore, we map additional phosphorylation sites as well as a previously unknown ATP/ADP-binding pocket in the large C-terminal domain and show enhanced thermal stabilization of other CCCs by adenine nucleotides. These findings provide fundamentally new insights into the complex regulation of KCCs and may unlock innovative strategies for drug development.
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Affiliation(s)
- Gamma Chi
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Rebecca Ebenhoch
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
- Present address:
MedChem, Boehringer Ingelheim Pharma GmbH & Co. KGBiberachGermany
| | - Henry Man
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
- Present address:
Exscientia LtdOxfordUK
| | - Haiping Tang
- Physical and Theoretical Chemistry LaboratoryUniversity of OxfordOxfordUK
| | - Laurence E Tremblay
- Department of MedicineNephrology Research GroupFaculty of MedicineLaval UniversityQuebec CityQCCanada
| | | | - Xingyu Qiu
- Physical and Theoretical Chemistry LaboratoryUniversity of OxfordOxfordUK
| | - Tina Bohstedt
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | | | | | - Alexandre P Garneau
- Department of MedicineNephrology Research GroupFaculty of MedicineLaval UniversityQuebec CityQCCanada
- Cardiometabolic Axis, School of Kinesiology and Physical Activity SciencesUniversity of MontréalMontréalQCCanada
| | - Dong Wang
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Gavin McKinley
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Christophe P Moreau
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Present address:
Celonic AGBaselGermany
| | | | - Patrizia Abrusci
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
- Present address:
Exscientia LtdOxfordUK
| | - Shubhashish M M Mukhopadhyay
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Alejandra Fernandez‐Cid
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Samira Slimani
- Department of MedicineNephrology Research GroupFaculty of MedicineLaval UniversityQuebec CityQCCanada
| | - Julie L Lavoie
- Cardiometabolic Axis, School of Kinesiology and Physical Activity SciencesUniversity of MontréalMontréalQCCanada
| | - Nicola A Burgess‐Brown
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
| | | | - Frank DiMaio
- Department of BiochemistryUniversity of WashingtonSeattleWAUSA
| | | | - Paul Isenring
- Department of MedicineNephrology Research GroupFaculty of MedicineLaval UniversityQuebec CityQCCanada
| | - Carol V Robinson
- Physical and Theoretical Chemistry LaboratoryUniversity of OxfordOxfordUK
| | - Katharina L Dürr
- Nuffield Department of MedicineCentre of Medicines DiscoveryUniversity of OxfordOxfordUK
- Structural Genomics ConsortiumNuffield Department of MedicineUniversity of OxfordOxfordUK
- OMass Therapeutics, Ltd.OxfordUK
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23
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Dzhala VI, Staley KJ. KCC2 Chloride Transport Contributes to the Termination of Ictal Epileptiform Activity. eNeuro 2021; 8:ENEURO.0208-20.2020. [PMID: 33239270 PMCID: PMC7986536 DOI: 10.1523/eneuro.0208-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 01/10/2023] Open
Abstract
Recurrent seizures intensely activate GABAA receptors (GABAA-Rs), which induces transient neuronal chloride ([Cl-]i) elevations and depolarizing GABA responses that contribute to the failure of inhibition that engenders further seizures and anticonvulsant resistance. The K+-Cl- cotransporter KCC2 is responsible for Cl- extrusion and restoration of [Cl-]i equilibrium (ECl) after synaptic activity, but at the cost of increased extracellular potassium which may retard K+-Cl- extrusion, depolarize neurons, and potentiate seizures. Thus, KCC2 may either diminish or facilitate seizure activity, and both proconvulsant and anticonvulsant effects of KCC2 inhibition have been reported. It is now necessary to identify the loci of these divergent responses by assaying both the electrographic effects and the ionic effects of KCC2 manipulation. We therefore determined the net effects of KCC2 transport activity on cytoplasmic chloride elevation and Cl- extrusion rates during spontaneous recurrent ictal-like epileptiform discharges (ILDs) in organotypic hippocampal slices in vitro, as well as the correlation between ionic and electrographic effects. We found that the KCC2 antagonist VU0463271 reduced Cl- extrusion rates, increased ictal [Cl-]i elevation, increased ILD duration, and induced status epilepticus (SE). In contrast, the putative KCC2 upregulator CLP257 improved chloride homeostasis and reduced the duration and frequency of ILDs in a concentration-dependent manner. Our results demonstrate that measuring both the ionic and electrographic effects of KCC2 transport clarify the impact of KCC2 modulation in specific models of epileptiform activity. Anticonvulsant effects predominate when KCC2-mediated chloride transport rather than potassium buffering is the rate-limiting step in restoring ECl and the efficacy of GABAergic inhibition during recurrent ILDs.
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Affiliation(s)
- Volodymyr I Dzhala
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114
- Harvard Medical School, Boston, MA 02114
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114
- Harvard Medical School, Boston, MA 02114
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24
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Josiah SS, Meor Azlan NF, Zhang J. Targeting the WNK-SPAK/OSR1 Pathway and Cation-Chloride Cotransporters for the Therapy of Stroke. Int J Mol Sci 2021; 22:1232. [PMID: 33513812 PMCID: PMC7865768 DOI: 10.3390/ijms22031232] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/22/2021] [Accepted: 01/24/2021] [Indexed: 02/05/2023] Open
Abstract
Stroke is one of the major culprits responsible for morbidity and mortality worldwide, and the currently available pharmacological strategies to combat this global disease are scanty. Cation-chloride cotransporters (CCCs) are expressed in several tissues (including neurons) and extensively contribute to the maintenance of numerous physiological functions including chloride homeostasis. Previous studies have implicated two CCCs, the Na+-K+-Cl- and K+-Cl- cotransporters (NKCCs and KCCs) in stroke episodes along with their upstream regulators, the with-no-lysine kinase (WNKs) family and STE20/SPS1-related proline/alanine rich kinase (SPAK) or oxidative stress response kinase (OSR1) via a signaling pathway. As the WNK-SPAK/OSR1 pathway reciprocally regulates NKCC and KCC, a growing body of evidence implicates over-activation and altered expression of NKCC1 in stroke pathology whilst stimulation of KCC3 during and even after a stroke event is neuroprotective. Both inhibition of NKCC1 and activation of KCC3 exert neuroprotection through reduction in intracellular chloride levels and thus could be a novel therapeutic strategy. Hence, this review summarizes the current understanding of functional regulations of the CCCs implicated in stroke with particular focus on NKCC1, KCC3, and WNK-SPAK/OSR1 signaling and discusses the current and potential pharmacological treatments for stroke.
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Affiliation(s)
| | | | - Jinwei Zhang
- Hatherly Laboratories, Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Exeter EX4 4PS, UK; (S.S.J.); (N.F.M.A.)
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25
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Xu H, Fame RM, Sadegh C, Sutin J, Naranjo C, Della Syau, Cui J, Shipley FB, Vernon A, Gao F, Zhang Y, Holtzman MJ, Heiman M, Warf BC, Lin PY, Lehtinen MK. Choroid plexus NKCC1 mediates cerebrospinal fluid clearance during mouse early postnatal development. Nat Commun 2021; 12:447. [PMID: 33469018 PMCID: PMC7815709 DOI: 10.1038/s41467-020-20666-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 12/10/2020] [Indexed: 12/14/2022] Open
Abstract
Cerebrospinal fluid (CSF) provides vital support for the brain. Abnormal CSF accumulation, such as hydrocephalus, can negatively affect perinatal neurodevelopment. The mechanisms regulating CSF clearance during the postnatal critical period are unclear. Here, we show that CSF K+, accompanied by water, is cleared through the choroid plexus (ChP) during mouse early postnatal development. We report that, at this developmental stage, the ChP showed increased ATP production and increased expression of ATP-dependent K+ transporters, particularly the Na+, K+, Cl-, and water cotransporter NKCC1. Overexpression of NKCC1 in the ChP resulted in increased CSF K+ clearance, increased cerebral compliance, and reduced circulating CSF in the brain without changes in intracranial pressure in mice. Moreover, ChP-specific NKCC1 overexpression in an obstructive hydrocephalus mouse model resulted in reduced ventriculomegaly. Collectively, our results implicate NKCC1 in regulating CSF K+ clearance through the ChP in the critical period during postnatal neurodevelopment in mice.
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Affiliation(s)
- Huixin Xu
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Ryann M Fame
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Cameron Sadegh
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Jason Sutin
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Christopher Naranjo
- Summer Honors Undergraduate Research Program, Division of Medical Sciences, Harvard Medical School, Boston, MA, 02115, USA
| | - Della Syau
- Summer Honors Undergraduate Research Program, Division of Medical Sciences, Harvard Medical School, Boston, MA, 02115, USA
| | - Jin Cui
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Frederick B Shipley
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
| | - Amanda Vernon
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Fan Gao
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Bioinformatics Resource Center in the Beckman Institute at Caltech, Pasadena, CA, 91125, USA
| | - Yong Zhang
- Pulmonary and Critical Care Medicine, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Michael J Holtzman
- Pulmonary and Critical Care Medicine, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Myriam Heiman
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Benjamin C Warf
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Pei-Yi Lin
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Maria K Lehtinen
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA.
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA.
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26
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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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27
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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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28
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Kitayama T. The Role of Astrocytes in the Modulation ofK +-Cl --Cotransporter-2 Function. Int J Mol Sci 2020; 21:E9539. [PMID: 33333849 PMCID: PMC7765297 DOI: 10.3390/ijms21249539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/10/2020] [Accepted: 12/13/2020] [Indexed: 11/21/2022] Open
Abstract
Neuropathic pain is characterized by spontaneous pain, pain sensations, and tactile allodynia. The pain sensory system normally functions under a fine balance between excitation and inhibition. Neuropathic pain arises when this balance is lost for some reason. In past reports, various mechanisms of neuropathic pain development have been reported, one of which is the downregulation of K+-Cl--cotransporter-2 (KCC2) expression. In fact, various neuropathic pain models indicate a decrease in KCC2 expression. This decrease in KCC2 expression is often due to a brain-derived neurotrophic factor that is released from microglia. However, a similar reaction has been reported in astrocytes, and it is unclear whether astrocytes or microglia are more important. This review discusses the hypothesis that astrocytes have a crucial influence on the alteration of KCC2 expression.
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Affiliation(s)
- Tomoya Kitayama
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Hyogo 663-8179, Japan
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29
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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: 16] [Impact Index Per Article: 4.0] [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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30
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Environmental regulation of the chloride transporter KCC2: switching inflammation off to switch the GABA on? Transl Psychiatry 2020; 10:349. [PMID: 33060559 PMCID: PMC7562743 DOI: 10.1038/s41398-020-01027-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/08/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022] Open
Abstract
Chloride homeostasis, the main determinant factor for the dynamic tuning of GABAergic inhibition during development, has emerged as a key element altered in a wide variety of brain disorders. Accordingly, developmental disorders such as schizophrenia, Autism Spectrum Disorder, Down syndrome, epilepsy, and tuberous sclerosis complex (TSC) have been associated with alterations in the expression of genes codifying for either of the two cotransporters involved in the excitatory-to-inhibitory GABA switch, KCC2 and NKCC1. These alterations can result from environmental insults, including prenatal stress and maternal separation which share, as common molecular denominator, the elevation of pro-inflammatory cytokines. In this review we report and systemize recent research articles indicating that different perinatal environmental perturbations affect the expression of chloride transporters, delaying the developmental switch of GABA signaling, and that inflammatory cytokines, in particular interleukin 1β, may represent a key causal factor for this phenomenon. Based on literature data, we provide therefore a unifying conceptual framework, linking environmental hits with the excitatory-to-inhibitory GABA switch in the context of brain developmental disorders.
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Xu N, Lei L, Lin Y, Ju LS, Morey TE, Gravenstein N, Yang J, Martynyuk AE. A Methyltransferase Inhibitor (Decitabine) Alleviates Intergenerational Effects of Paternal Neonatal Exposure to Anesthesia With Sevoflurane. Anesth Analg 2020; 131:1291-1299. [PMID: 32925350 PMCID: PMC7593836 DOI: 10.1213/ane.0000000000005097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Neonatal exposure to sevoflurane induces neurobehavioral and neuroendocrine abnormalities in exposed male rats (generation F0) and neurobehavioral, but not neuroendocrine, abnormalities in their male, but not female, offspring (generation F1). These effects of sevoflurane are accompanied by a hypermethylated neuron-specific K-2Cl (Kcc2) Cl exporter gene in the F0 spermatozoa and the F1 male hypothalamus, while the gene's expression is reduced in the F0 and F1 hypothalamus. We investigated whether inhibition of deoxyribonucleic acid methyltransferases (DNMTs) before paternal sevoflurane exposure could alleviate the anesthetic's F0 and F1 effects. METHODS Sprague-Dawley male rats were anesthetized with 2.1% sevoflurane for 5 hours on postnatal day (P) 5 and mated with control females on P90 to generate offspring. The nonselective DNMT inhibitor decitabine (0.5 mg/kg, intraperitoneally) was administered 30 minutes before sevoflurane exposure. The F0 and F1 male rats were evaluated in in vivo and in vitro tests in adulthood. RESULTS Paternal exposure to sevoflurane induced impaired prepulse inhibition of the acoustic startle response and exacerbated corticosterone responses to stress in F0 males and impaired prepulse inhibition of the startle responses in F1 males. These effects were accompanied in both generations by reduced and increased expressions of hypothalamic Kcc2 and Dnmt3a/b, respectively. Decitabine deterred the effects of paternal exposure to sevoflurane in F0 and F1 males. CONCLUSIONS These results suggest that similar decitabine-sensitive mechanisms regulating expression of multiple genes are involved in the mediation of neurobehavioral abnormalities in sires neonatally exposed to sevoflurane and in their future unexposed male offspring.
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Affiliation(s)
- Ning Xu
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
| | - Lei Lei
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
| | - Yunan Lin
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
| | - Ling-Sha Ju
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
| | - Timothy E. Morey
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
| | - Nikolaus Gravenstein
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida
| | - Jianjun Yang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Anatoly E. Martynyuk
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida
- McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida
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Abstract
Protein modifications in neurons during early development regulate pain sensation and cognition.
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Zhang J, Cordshagen A, Medina I, Nothwang HG, Wisniewski JR, Winklhofer M, Hartmann AM. Staurosporine and NEM mainly impair WNK-SPAK/OSR1 mediated phosphorylation of KCC2 and NKCC1. PLoS One 2020; 15:e0232967. [PMID: 32413057 PMCID: PMC7228128 DOI: 10.1371/journal.pone.0232967] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/24/2020] [Indexed: 02/05/2023] Open
Abstract
The pivotal role of KCC2 and NKCC1 in development and maintenance of fast inhibitory neurotransmission and their implication in severe human diseases arouse interest in posttranscriptional regulatory mechanisms such as (de)phosphorylation. Staurosporine (broad kinase inhibitor) and N-ethylmalemide (NEM) that modulate kinase and phosphatase activities enhance KCC2 and decrease NKCC1 activity. Here, we investigated the regulatory mechanism for this reciprocal regulation by mass spectrometry and immunoblot analyses using phospho-specific antibodies. Our analyses revealed that application of staurosporine or NEM dephosphorylates Thr1007 of KCC2, and Thr203, Thr207 and Thr212 of NKCC1. Dephosphorylation of Thr1007 of KCC2, and Thr207 and Thr212 of NKCC1 were previously demonstrated to activate KCC2 and to inactivate NKCC1. In addition, application of the two agents resulted in dephosphorylation of the T-loop and S-loop phosphorylation sites Thr233 and Ser373 of SPAK, a critical kinase in the WNK-SPAK/OSR1 signaling module mediating phosphorylation of KCC2 and NKCC1. Taken together, these results suggest that reciprocal regulation of KCC2 and NKCC1 via staurosporine and NEM is based on WNK-SPAK/OSR1 signaling. The key regulatory phospho-site Ser940 of KCC2 is not critically involved in the enhanced activation of KCC2 upon staurosporine and NEM treatment, as both agents have opposite effects on its phosphorylation status. Finally, NEM acts in a tissue-specific manner on Ser940, as shown by comparative analysis in HEK293 cells and immature cultured hippocampal neurons. In summary, our analyses identified phospho-sites that are responsive to staurosporine or NEM application. This provides important information towards a better understanding of the cooperative interactions of different phospho-sites.
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Affiliation(s)
- Jinwei Zhang
- Hatherly Laboratories, Medical School, College of Medicine and Health, Institute of Biomedical and Clinical Sciences, University of Exeter, Exeter, United Kingdom
- Xiamen Cardiovascular Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Antje Cordshagen
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Igor Medina
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University UMR 1249, Marseille, France
| | - Hans Gerd Nothwang
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Center of Excellence Hearing4all, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Jacek R. Wisniewski
- Department of Proteomics and Signal Transduction, Biochemical Proteomics Group, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Michael Winklhofer
- Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Institute for Biology and Environmental Sciences IBU, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Anna-Maria Hartmann
- Division of Neurogenetics, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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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: 8] [Impact Index Per Article: 2.0] [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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Maguire JL. Get With the (Developmental) Program. Epilepsy Curr 2020; 20:102-104. [PMID: 32313506 PMCID: PMC7160877 DOI: 10.1177/1535759720901606] [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] [Indexed: 11/16/2022] Open
Abstract
Impaired Regulation of KCC2 Phosphorylation Leads to Neuronal Network Dysfunction and Neurodevelopmental Pathology Pisella LI, Gaiarsa JL, Diabira D, et al. Sci Signal. 2019:12(603):eaay0300. doi:10.1126/scisignal.aay0300. KCC2 is a vital neuronal K+/Cl− cotransporter that is implicated in the etiology of numerous neurological diseases. In normal cells, KCC2 undergoes developmental dephosphorylation at Thr906 and Thr1007. We engineered mice with heterozygous phosphomimetic mutations T906E and T1007E (KCC2E/+) to prevent the normal developmental dephosphorylation of these sites. Immature (postnatal day 15) but not juvenile (postnatal day 30) KCC2E/+ mice exhibited altered GABAergic inhibition, an increased glutamate/GABA synaptic ratio, and greater susceptibility to seizure. KCC2E/+ mice also had abnormal ultrasonic vocalizations at postnatal days 10 to 12 and impaired social behavior at postnatal day 60. Postnatal bumetanide treatment restored network activity by postnatal day 15 but failed to restore social behavior by postnatal day 60. Our data indicate that posttranslational KCC2 regulation controls the GABAergic developmental sequence in vivo, indicating that deregulation of KCC2 could be a risk factor for the emergence of neurological pathology. Developmental Regulation of KCC2 Phosphorylation Has Long-Term Impacts on Cognitive Function Moore YE, Conway LC, Wobst HJ, et al. Front Mol Neurosci. 2019;12:173. doi:10.3389/fnmol.2019.00173. The GABAA receptor-mediated currents shift from excitatory to inhibitory during postnatal brain development in rodents. A postnatal increase in KCC2 protein expression is considered to be the sole mechanism controlling the developmental onset of hyperpolarizing synaptic transmission, but here we identify a key role for KCC2 phosphorylation in the developmental EGABA shift. Preventing phosphorylation of KCC2 in vivo at either residue serine 940 (S940), or at residues threonine 906 and threonine 1007 (T906/T1007), delayed or accelerated the postnatal onset of KCC2 function, respectively. Several models of neurodevelopmental disorders including Rett syndrome, Fragile × and Down syndrome exhibit delayed postnatal onset of hyperpolarizing GABAergic inhibition, but whether the timing of the onset of hyperpolarizing synaptic inhibition during development plays a role in establishing adulthood cognitive function is unknown; we have used the distinct KCC2-S940A and KCC2-T906A/T1007A knock-in mouse models to address this issue. Altering KCC2 function resulted in long-term abnormalities in social behavior and memory retention. Tight regulation of KCC2 phosphorylation is therefore required for the typical timing of the developmental onset of hyperpolarizing synaptic inhibition, and it plays a fundamental role in the regulation of adulthood cognitive function.
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Tang BL. The Expanding Therapeutic Potential of Neuronal KCC2. Cells 2020; 9:E240. [PMID: 31963584 PMCID: PMC7016893 DOI: 10.3390/cells9010240] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 02/06/2023] Open
Abstract
Dysfunctions in GABAergic inhibitory neural transmission occur in neuronal injuries and neurological disorders. The potassium-chloride cotransporter 2 (KCC2, SLC12A5) is a key modulator of inhibitory GABAergic inputs in healthy adult neurons, as its chloride (Cl-) extruding activity underlies the hyperpolarizing reversal potential for GABAA receptor Cl- currents (EGABA). Manipulation of KCC2 levels or activity improve symptoms associated with epilepsy and neuropathy. Recent works have now indicated that pharmacological enhancement of KCC2 function could reactivate dormant relay circuits in an injured mouse's spinal cord, leading to functional recovery and the attenuation of neuronal abnormality and disease phenotype associated with a mouse model of Rett syndrome (RTT). KCC2 interacts with Huntingtin and is downregulated in Huntington's disease (HD), which contributed to GABAergic excitation and memory deficits in the R6/2 mouse HD model. Here, these recent advances are highlighted, which attest to KCC2's growing potential as a therapeutic target for neuropathological conditions resulting from dysfunctional inhibitory input.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore; ; Tel.: +65-6516-1040
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077, Singapore
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Escher J, Ford LD. General anesthesia, germ cells and the missing heritability of autism: an urgent need for research. ENVIRONMENTAL EPIGENETICS 2020; 6:dvaa007. [PMID: 32704384 PMCID: PMC7368377 DOI: 10.1093/eep/dvaa007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/31/2020] [Accepted: 04/14/2020] [Indexed: 05/08/2023]
Abstract
Agents of general anesthesia (GA) are commonly employed in surgical, dental and diagnostic procedures to effectuate global suppression of the nervous system, but in addition to somatic targets, the subject's germ cells-from the embryonic primordial stage to the mature gametes-may likewise be exposed. Although GA is generally considered safe for most patients, evidence has accumulated that various compounds, in particular the synthetic volatile anesthetic gases (SVAGs) such as sevoflurane, can exert neurotoxic, genotoxic and epigenotoxic effects, with adverse consequences for cellular and genomic function in both somatic and germline cells. The purpose of this paper is to review the evidence demonstrating that GA, and in particular, SVAGs, may in some circumstances adversely impact the molecular program of germ cells, resulting in brain and behavioral pathology in the progeny born of the exposed cells. Further, we exhort the medical and scientific communities to undertake comprehensive experimental and epidemiological research programs to address this critical gap in risk assessment.
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Affiliation(s)
- Jill Escher
- Correspondence address. Escher Fund for Autism, 1590 Calaveras Avenue, San Jose, CA 95126, USA. E-mail:
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Zamponi GW. Tuning the regulator: Phosphorylation of KCC2 at two specific sites is critical for neurodevelopment. Sci Signal 2019; 12:12/603/eaay8960. [PMID: 31615900 DOI: 10.1126/scisignal.aay8960] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The K+/Cl- cotransporter KCC2 is a molecular switch between excitatory and inhibitory effects of GABAergic inputs into neurons. In a pair of exciting studies, Watanabe et al. and Pisella et al. elucidate the role of KCC2 dephosphorylation in this process and reveal its consequences for neurodevelopment and nervous system pathology.
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Affiliation(s)
- Gerald W Zamponi
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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