1
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Wu Z, Yu W, Song Y, Zhao P. General anaesthesia, the developing brain, and cerebral white matter alterations: a narrative review. Br J Anaesth 2023; 131:1022-1029. [PMID: 37833128 DOI: 10.1016/j.bja.2023.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 09/03/2023] [Accepted: 09/06/2023] [Indexed: 10/15/2023] Open
Abstract
The potential neurotoxic impact of anaesthetic agents has been the subject of sustained debate and continuing research. White matter, which comprises more than half of the brain volume and largely consists of myelinated axonal bundles, is critical for communication between diverse brain regions and for supporting neurobehavioural function. Evidence points to a correlation between exposure to anaesthesia and white matter alterations, which might underpin the ensuing cognitive and behavioural abnormalities. This review summarises the neuropathological and neuroimaging findings related to anaesthesia-induced white matter alterations in the developing brain. Future research is required to understand the effects of anaesthesia exposure on white matter development.
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Affiliation(s)
- Ziyi Wu
- Department of Anaesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Weiwei Yu
- Department of Anaesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yanhong Song
- Department of Anaesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Ping Zhao
- Department of Anaesthesiology, Shengjing Hospital of China Medical University, Shenyang, China.
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2
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Boyarko B, Podvin S, Greenberg B, Momper JD, Huang Y, Gerwick WH, Bang AG, Quinti L, Griciuc A, Kim DY, Tanzi RE, Feldman HH, Hook V. Evaluation of bumetanide as a potential therapeutic agent for Alzheimer's disease. Front Pharmacol 2023; 14:1190402. [PMID: 37601062 PMCID: PMC10436590 DOI: 10.3389/fphar.2023.1190402] [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: 03/20/2023] [Accepted: 06/28/2023] [Indexed: 08/22/2023] Open
Abstract
Therapeutics discovery and development for Alzheimer's disease (AD) has been an area of intense research to alleviate memory loss and the underlying pathogenic processes. Recent drug discovery approaches have utilized in silico computational strategies for drug candidate selection which has opened the door to repurposing drugs for AD. Computational analysis of gene expression signatures of patients stratified by the APOE4 risk allele of AD led to the discovery of the FDA-approved drug bumetanide as a top candidate agent that reverses APOE4 transcriptomic brain signatures and improves memory deficits in APOE4 animal models of AD. Bumetanide is a loop diuretic which inhibits the kidney Na+-K+-2Cl- cotransporter isoform, NKCC2, for the treatment of hypertension and edema in cardiovascular, liver, and renal disease. Electronic health record data revealed that patients exposed to bumetanide have lower incidences of AD by 35%-70%. In the brain, bumetanide has been proposed to antagonize the NKCC1 isoform which mediates cellular uptake of chloride ions. Blocking neuronal NKCC1 leads to a decrease in intracellular chloride and thus promotes GABAergic receptor mediated hyperpolarization, which may ameliorate disease conditions associated with GABAergic-mediated depolarization. NKCC1 is expressed in neurons and in all brain cells including glia (oligodendrocytes, microglia, and astrocytes) and the vasculature. In consideration of bumetanide as a repurposed drug for AD, this review evaluates its pharmaceutical properties with respect to its estimated brain levels across doses that can improve neurologic disease deficits of animal models to distinguish between NKCC1 and non-NKCC1 mechanisms. The available data indicate that bumetanide efficacy may occur at brain drug levels that are below those required for inhibition of the NKCC1 transporter which implicates non-NKCC1 brain mechansims for improvement of brain dysfunctions and memory deficits. Alternatively, peripheral bumetanide mechanisms may involve cells outside the central nervous system (e.g., in epithelia and the immune system). Clinical bumetanide doses for improved neurological deficits are reviewed. Regardless of mechanism, the efficacy of bumetanide to improve memory deficits in the APOE4 model of AD and its potential to reduce the incidence of AD provide support for clinical investigation of bumetanide as a repurposed AD therapeutic agent.
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Affiliation(s)
- Ben Boyarko
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Barry Greenberg
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jeremiah D. Momper
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, United States
- Departments of Neurology and Pathology, University of California, San Francisco, San Francisco, CA, United States
| | - William H. Gerwick
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Anne G. Bang
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys, San Diego, CA, United States
| | - Luisa Quinti
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Ana Griciuc
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Doo Yeon Kim
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Howard H. Feldman
- Department of Neurosciences and Department of Pharmacology, University of California, San Diego, San Diego, United States
- Alzheimer’s Disease Cooperative Study, University of California, San Diego, La Jolla, CA, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
- Department of Neurosciences and Department of Pharmacology, University of California, San Diego, San Diego, United States
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3
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Del Turco D, Paul MH, Schlaudraff J, Muellerleile J, Bozic F, Vuksic M, Jedlicka P, Deller T. Layer-specific changes of KCC2 and NKCC1 in the mouse dentate gyrus after entorhinal denervation. Front Mol Neurosci 2023; 16:1118746. [PMID: 37293543 PMCID: PMC10244516 DOI: 10.3389/fnmol.2023.1118746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 04/25/2023] [Indexed: 06/10/2023] Open
Abstract
The cation-chloride cotransporters KCC2 and NKCC1 regulate the intracellular Cl- concentration and cell volume of neurons and/or glia. The Cl- extruder KCC2 is expressed at higher levels than the Cl- transporter NKCC1 in mature compared to immature neurons, accounting for the developmental shift from high to low Cl- concentration and from depolarizing to hyperpolarizing currents through GABA-A receptors. Previous studies have shown that KCC2 expression is downregulated following central nervous system injury, returning neurons to a more excitable state, which can be pathological or adaptive. Here, we show that deafferentation of the dendritic segments of granule cells in the outer (oml) and middle (mml) molecular layer of the dentate gyrus via entorhinal denervation in vivo leads to cell-type- and layer-specific changes in the expression of KCC2 and NKCC1. Microarray analysis validated by reverse transcription-quantitative polymerase chain reaction revealed a significant decrease in Kcc2 mRNA in the granule cell layer 7 days post-lesion. In contrast, Nkcc1 mRNA was upregulated in the oml/mml at this time point. Immunostaining revealed a selective reduction in KCC2 protein expression in the denervated dendrites of granule cells and an increase in NKCC1 expression in reactive astrocytes in the oml/mml. The NKCC1 upregulation is likely related to the increased activity of astrocytes and/or microglia in the deafferented region, while the transient KCC2 downregulation in granule cells may be associated with denervation-induced spine loss, potentially also serving a homeostatic role via boosting GABAergic depolarization. Furthermore, the delayed KCC2 recovery might be involved in the subsequent compensatory spinogenesis.
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Affiliation(s)
- Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Mandy H. Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Jessica Schlaudraff
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Julia Muellerleile
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Fran Bozic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Mario Vuksic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
- Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
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4
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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5
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Kurki SN, Uvarov P, Pospelov AS, Trontti K, Hübner AK, Srinivasan R, Watanabe M, Hovatta I, Hübner CA, Kaila K, Virtanen MA. Expression patterns of NKCC1 in neurons and non-neuronal cells during cortico-hippocampal development. Cereb Cortex 2022; 33:5906-5923. [PMID: 36573432 PMCID: PMC10183754 DOI: 10.1093/cercor/bhac470] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/05/2022] [Accepted: 11/06/2022] [Indexed: 12/28/2022] Open
Abstract
Abstract
The Na-K-2Cl cotransporter NKCC1 is widely expressed in cells within and outside the brain. However, our understanding of its roles in brain functions throughout development, as well as in neuropsychiatric and neurological disorders, has been severely hindered by the lack of reliable data on its developmental and (sub)cellular expression patterns. We provide here the first properly controlled analysis of NKCC1 protein expression in various cell types of the mouse brain using custom-made antibodies and an NKCC1 knock-out validated immunohistochemical procedure, with parallel data based on advanced mRNA approaches. NKCC1 protein and mRNA are expressed at remarkably high levels in oligodendrocytes. In immature neurons, NKCC1 protein was located in the somata, whereas in adult neurons, only NKCC1 mRNA could be clearly detected. NKCC1 immunoreactivity is also seen in microglia, astrocytes, developing pericytes, and in progenitor cells of the dentate gyrus. Finally, a differential expression of NKCC1 splice variants was observed, with NKCC1a predominating in non-neuronal cells and NKCC1b in neurons. Taken together, our data provide a cellular basis for understanding NKCC1 functions in the brain and enable the identification of major limitations and promises in the development of neuron-targeting NKCC1-blockers.
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Affiliation(s)
- Samu N Kurki
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
| | - Pavel Uvarov
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
| | - Alexey S Pospelov
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
| | - Kalevi Trontti
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
- University of Helsinki SleepWell Research Program, Faculty of Medicine, , 00014 Helsinki , Finland
- University of Helsinki Department of Psychology and Logopedics, , 00014 Helsinki , Finland
| | - Antje K Hübner
- Jena University Hospital, Friedrich Schiller Universität Institute of Human Genetics, , 07747 Jena , Germany
| | - Rakenduvadhana Srinivasan
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
| | - Masahiko Watanabe
- Hokkaido University Department of Anatomy, Faculty of Medicine, , Sapporo 060–8638 , Japan
| | - Iiris Hovatta
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
- University of Helsinki SleepWell Research Program, Faculty of Medicine, , 00014 Helsinki , Finland
- University of Helsinki Department of Psychology and Logopedics, , 00014 Helsinki , Finland
| | - Christian A Hübner
- Jena University Hospital, Friedrich Schiller Universität Institute of Human Genetics, , 07747 Jena , Germany
| | - Kai Kaila
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
| | - Mari A Virtanen
- University of Helsinki Molecular and Integrative Biosciences, , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki Neuroscience Center, , 00014 Helsinki , Finland
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6
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Emerging Roles of Cholinergic Receptors in Schwann Cell Development and Plasticity. Biomedicines 2022; 11:biomedicines11010041. [PMID: 36672549 PMCID: PMC9855772 DOI: 10.3390/biomedicines11010041] [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: 08/07/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 12/29/2022] Open
Abstract
The cross talk between neurons and glial cells during development, adulthood, and disease, has been extensively documented. Among the molecules mediating these interactions, neurotransmitters play a relevant role both in myelinating and non-myelinating glial cells, thus resulting as additional candidates regulating the development and physiology of the glial cells. In this review, we summarise the contribution of the main neurotransmitter receptors in the regulation of the morphogenetic events of glial cells, with particular attention paid to the role of acetylcholine receptors in Schwann cell physiology. In particular, the M2 muscarinic receptor influences Schwann cell phenotype and the α7 nicotinic receptor is emerging as influential in the modulation of peripheral nerve regeneration and inflammation. This new evidence significantly improves our knowledge of Schwann cell development and function and may contribute to identifying interesting new targets to support the activity of these cells in pathological conditions.
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7
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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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8
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Tóth K, Lénárt N, Berki P, Fekete R, Szabadits E, Pósfai B, Cserép C, Alatshan A, Benkő S, Kiss D, Hübner CA, Gulyás A, Kaila K, Környei Z, Dénes Á. The NKCC1 ion transporter modulates microglial phenotype and inflammatory response to brain injury in a cell-autonomous manner. PLoS Biol 2022; 20:e3001526. [PMID: 35085235 PMCID: PMC8856735 DOI: 10.1371/journal.pbio.3001526] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/18/2022] [Accepted: 01/04/2022] [Indexed: 12/25/2022] Open
Abstract
The NKCC1 ion transporter contributes to the pathophysiology of common neurological disorders, but its function in microglia, the main inflammatory cells of the brain, has remained unclear to date. Therefore, we generated a novel transgenic mouse line in which microglial NKCC1 was deleted. We show that microglial NKCC1 shapes both baseline and reactive microglia morphology, process recruitment to the site of injury, and adaptation to changes in cellular volume in a cell-autonomous manner via regulating membrane conductance. In addition, microglial NKCC1 deficiency results in NLRP3 inflammasome priming and increased production of interleukin-1β (IL-1β), rendering microglia prone to exaggerated inflammatory responses. In line with this, central (intracortical) administration of the NKCC1 blocker, bumetanide, potentiated intracortical lipopolysaccharide (LPS)-induced cytokine levels. In contrast, systemic bumetanide application decreased inflammation in the brain. Microglial NKCC1 KO animals exposed to experimental stroke showed significantly increased brain injury, inflammation, cerebral edema and worse neurological outcome. Thus, NKCC1 emerges as an important player in controlling microglial ion homeostasis and inflammatory responses through which microglia modulate brain injury. The contribution of microglia to central NKCC1 actions is likely to be relevant for common neurological disorders.
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Affiliation(s)
- Krisztina Tóth
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Nikolett Lénárt
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Péter Berki
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Rebeka Fekete
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Eszter Szabadits
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Pósfai
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Csaba Cserép
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ahmad Alatshan
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular Cellular and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Szilvia Benkő
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular Cellular and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dániel Kiss
- Software Engineering Institute, John von Neumann Faculty of Informatics, Óbuda University, Budapest, Hungary
| | | | - Attila Gulyás
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Kai Kaila
- Molecular and Integrative Biosciences and Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Zsuzsanna Környei
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ádám Dénes
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
- * E-mail:
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9
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Yamazaki Y, Abe Y, Fujii S, Tanaka KF. Oligodendrocytic Na +-K +-Cl - co-transporter 1 activity facilitates axonal conduction and restores plasticity in the adult mouse brain. Nat Commun 2021; 12:5146. [PMID: 34446732 PMCID: PMC8390751 DOI: 10.1038/s41467-021-25488-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 08/13/2021] [Indexed: 11/30/2022] Open
Abstract
The juvenile brain presents plasticity. Oligodendrocytes are the myelinating cells of the central nervous system and myelination can be adaptive. Plasticity decreases from juvenile to adulthood. The mechanisms involving oligodendrocytes underlying plasticity are unclear. Here, we show Na+-K+-Cl– co-transporter 1 (NKCC1), highly expressed in the juvenile mouse brain, regulates the oligodendrocyte activity from juvenile to adulthood in mice, as shown by optogenetic manipulation of oligodendrocytes. The reduced neuronal activity in adults was restored by Nkcc1 overexpression in oligodendrocytes. Moreover, in adult mice overexpressing Nkcc1, long-term potentiation and learning were facilitated compared to age-matched controls. These findings demonstrate that NKCC1 plays a regulatory role in the age-dependent activity of oligodendrocytes, furthermore inducing activation of NKCC1 in oligodendrocytes can restore neuronal plasticity in the adult mouse brain. Brain plasticity declines with age. Here, the authors show that NKCC1 regulates oligodendrocyte activity, facilitating neuronal plasticity during juvenile. Inducing activation of oligodendrocytic NKCC1 results in restoration of neuronal plasticity in the adult mouse brain.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan.
| | - Yoshifumi Abe
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
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10
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Moyon S, Frawley R, Marechal D, Huang D, Marshall-Phelps KLH, Kegel L, Bøstrand SMK, Sadowski B, Jiang YH, Lyons DA, Möbius W, Casaccia P. TET1-mediated DNA hydroxymethylation regulates adult remyelination in mice. Nat Commun 2021; 12:3359. [PMID: 34099715 PMCID: PMC8185117 DOI: 10.1038/s41467-021-23735-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/10/2021] [Indexed: 12/17/2022] Open
Abstract
The mechanisms regulating myelin repair in the adult central nervous system (CNS) are unclear. Here, we identify DNA hydroxymethylation, catalyzed by the Ten-Eleven-Translocation (TET) enzyme TET1, as necessary for myelin repair in young adults and defective in old mice. Constitutive and inducible oligodendrocyte lineage-specific ablation of Tet1 (but not of Tet2), recapitulate this age-related decline in repair of demyelinated lesions. DNA hydroxymethylation and transcriptomic analyses identify TET1-target in adult oligodendrocytes, as genes regulating neuro-glial communication, including the solute carrier (Slc) gene family. Among them, we show that the expression levels of the Na+/K+/Cl- transporter, SLC12A2, are higher in Tet1 overexpressing cells and lower in old or Tet1 knockout. Both aged mice and Tet1 mutants also present inefficient myelin repair and axo-myelinic swellings. Zebrafish mutants for slc12a2b also display swellings of CNS myelinated axons. Our findings suggest that TET1 is required for adult myelin repair and regulation of the axon-myelin interface.
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Affiliation(s)
- Sarah Moyon
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA.
| | - Rebecca Frawley
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | - Damien Marechal
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | - Dennis Huang
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | | | - Linde Kegel
- Centre for Discovery Brain Sciences, Edinburgh, UK
| | | | - Boguslawa Sadowski
- Department of Neurogenetics, Göttingen, Germany
- Electron Microscopy Core Unit, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Yong-Hui Jiang
- Department of Neurobiology and Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | | | - Wiebke Möbius
- Department of Neurogenetics, Göttingen, Germany
- Electron Microscopy Core Unit, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Patrizia Casaccia
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA.
- Program of Biology and Biochemistry, The Graduate Center of The City University of New York, New York, NY, USA.
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11
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Song S, Luo L, Sun B, Sun D. Roles of glial ion transporters in brain diseases. Glia 2019; 68:472-494. [PMID: 31418931 DOI: 10.1002/glia.23699] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 12/21/2022]
Abstract
Glial ion transporters are important in regulation of ionic homeostasis, cell volume, and cellular signal transduction under physiological conditions of the central nervous system (CNS). In response to acute or chronic brain injuries, these ion transporters can be activated and differentially regulate glial functions, which has subsequent impact on brain injury or tissue repair and functional recovery. In this review, we summarized the current knowledge about major glial ion transporters, including Na+ /H+ exchangers (NHE), Na+ /Ca2+ exchangers (NCX), Na+ -K+ -Cl- cotransporters (NKCC), and Na+ -HCO3 - cotransporters (NBC). In acute neurological diseases, such as ischemic stroke and traumatic brain injury (TBI), these ion transporters are rapidly activated and play significant roles in regulation of the intra- and extracellular pH, Na+ , K+ , and Ca2+ homeostasis, synaptic plasticity, and myelin formation. However, overstimulation of these ion transporters can contribute to glial apoptosis, demyelination, inflammation, and excitotoxicity. In chronic brain diseases, such as glioma, Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), glial ion transporters are involved in the glioma Warburg effect, glial activation, neuroinflammation, and neuronal damages. These findings suggest that glial ion transporters are involved in tissue structural and functional restoration, or brain injury and neurological disease development and progression. A better understanding of these ion transporters in acute and chronic neurological diseases will provide insights for their potential as therapeutic targets.
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Affiliation(s)
- Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lanxin Luo
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania.,School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China.,School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, China
| | - Baoshan Sun
- School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, China.,Pólo Dois Portos, Instituto National de Investigação Agrária e Veterinária, Dois Portos, Portugal
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania
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12
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Kharod SC, Kang SK, Kadam SD. Off-Label Use of Bumetanide for Brain Disorders: An Overview. Front Neurosci 2019; 13:310. [PMID: 31068771 PMCID: PMC6491514 DOI: 10.3389/fnins.2019.00310] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/19/2019] [Indexed: 01/17/2023] Open
Abstract
Bumetanide (BTN or BUM) is a FDA-approved potent loop diuretic (LD) that acts by antagonizing sodium-potassium-chloride (Na-K-Cl) cotransporters, NKCC1 (SLc12a2) and NKCC2. While NKCC1 is expressed both in the CNS and in systemic organs, NKCC2 is kidney-specific. The off-label use of BTN to modulate neuronal transmembrane Cl− gradients by blocking NKCC1 in the CNS has now been tested as an anti-seizure agent and as an intervention for neurological disorders in pre-clinical studies with varying results. BTN safety and efficacy for its off-label use has also been tested in several clinical trials for neonates, children, adolescents, and adults. It failed to meet efficacy criteria for hypoxic-ischemic encephalopathy (HIE) neonatal seizures. In contrast, positive outcomes in temporal lobe epilepsy (TLE), autism, and schizophrenia trials have been attributed to BTN in studies evaluating its off-label use. NKCC1 is an electroneutral neuronal Cl− importer and the dominance of NKCC1 function has been proposed as the common pathology for HIE seizures, TLE, autism, and schizophrenia. Therefore, the use of BTN to antagonize neuronal NKCC1 with the goal to lower internal Cl− levels and promote GABAergic mediated hyperpolarization has been proposed. In this review, we summarize the data and results for pre-clinical and clinical studies that have tested off-label BTN interventions and report variable outcomes. We also compare the data underlying the developmental expression profile of NKCC1 and KCC2, highlight the limitations of BTN’s brain-availability and consider its actions on non-neuronal cells.
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Affiliation(s)
- Shivani C Kharod
- Neuroscience Laboratory, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Seok Kyu Kang
- Neuroscience Laboratory, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States.,Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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13
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Bursting at the Seams: Molecular Mechanisms Mediating Astrocyte Swelling. Int J Mol Sci 2019; 20:ijms20020330. [PMID: 30650535 PMCID: PMC6359623 DOI: 10.3390/ijms20020330] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 01/31/2023] Open
Abstract
Brain swelling is one of the most robust predictors of outcome following brain injury, including ischemic, traumatic, hemorrhagic, metabolic or other injury. Depending on the specific type of insult, brain swelling can arise from the combined space-occupying effects of extravasated blood, extracellular edema fluid, cellular swelling, vascular engorgement and hydrocephalus. Of these, arguably the least well appreciated is cellular swelling. Here, we explore current knowledge regarding swelling of astrocytes, the most abundant cell type in the brain, and the one most likely to contribute to pathological brain swelling. We review the major molecular mechanisms identified to date that contribute to or mitigate astrocyte swelling via ion transport, and we touch upon the implications of astrocyte swelling in health and disease.
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14
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Káradóttir RT, Kuo CT. Neuronal Activity-Dependent Control of Postnatal Neurogenesis and Gliogenesis. Annu Rev Neurosci 2018; 41:139-161. [PMID: 29618286 DOI: 10.1146/annurev-neuro-072116-031054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The addition of new neurons and oligodendroglia in the postnatal and adult mammalian brain presents distinct forms of gray and white matter plasticity. Substantial effort has been devoted to understanding the cellular and molecular mechanisms controlling postnatal neurogenesis and gliogenesis, revealing important parallels to principles governing the embryonic stages. While during central nervous system development, scripted temporal and spatial patterns of neural and glial progenitor proliferation and differentiation are necessary to create the nervous system architecture, it remains unclear what driving forces maintain and sustain postnatal neural stem cell (NSC) and oligodendrocyte progenitor cell (OPC) production of new neurons and glia. In recent years, neuronal activity has been identified as an important modulator of these processes. Using the distinct properties of neurotransmitter ionotropic and metabotropic channels to signal downstream cellular events, NSCs and OPCs share common features in their readout of neuronal activity patterns. Here we review the current evidence for neuronal activity-dependent control of NSC/OPC proliferation and differentiation in the postnatal brain, highlight some potential mechanisms used by the two progenitor populations, and discuss future studies that might advance these research areas further.
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Affiliation(s)
- Ragnhildur T Káradóttir
- Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom; .,Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - Chay T Kuo
- Departments of Cell Biology and Neurobiology, Duke University School of Medicine, Durham, North Carolina 27710, USA; .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina 27710, USA.,Institute for Brain Sciences, Duke University, Durham, North Carolina 27708, USA
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15
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Yu Y, Fu P, Yu Z, Xie M, Wang W, Luo X. NKCC1 Inhibition Attenuates Chronic Cerebral Hypoperfusion-Induced White Matter Lesions by Enhancing Progenitor Cells of Oligodendrocyte Proliferation. J Mol Neurosci 2018; 64:449-458. [PMID: 29502291 DOI: 10.1007/s12031-018-1043-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/15/2018] [Indexed: 11/28/2022]
Abstract
Cerebral white matter is vulnerable to ischemic condition. However, no effective treatment to alleviate or restore the myelin damage caused by chronic cerebral hypoperfusion has been found. Na+-K+-Cl- cotransporter 1 (NKCC1), a Na+-K+-Cl- cotransporter widely expressed in the central nervous system (CNS), involves in regulation of cell swelling, EAA release, cell apoptosis, and proliferation. Nevertheless, the role of NKCC1 in chronic hypoperfusion-induced white matter lesions (WMLs) has not been explored. Here, mice subjected to bilateral common carotid artery stenosis (BCAS) were used as model of chronic cerebral hypoperfusion; density of progenitor cells of oligodendrocyte (OPCs), oligodendrocytes (OLs), astrocytes, and microglia was assessed by immunofluorescent staining and Western blot analysis; working memory was examined by eight-arm radial maze test; expression of MAPK signaling pathway was determined by Western blot analysis. After BCAS, white matter integrity disruption and working memory impairment were observed. NKCC1 inhibition by bumetanide administration enhanced OPC proliferation, attenuated chronic hypoperfusion-induced white matter damage, and promoted recovery of neurological function. However, NKCC1 inhibition caused no significant change in the densities of GFAP- and Iba-1-positive cells in the corpus callosum. Bumetanide administration significantly increased the expression of p-ERK and decreased the expression of p-JNK and p-p38 in comparison to vehicle-BCAS groups. In conclusion, NKCC1 inhibition might significantly ameliorate chronic cerebral hypoperfusion-induced WMLs and cognitive impairment by enhancing progenitor cells of oligodendrocyte proliferation, and this protective function of bumetanide might be mediated by modulation of the MAPK signaling pathway.
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Affiliation(s)
- Ying Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Peicai Fu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Zhiyuan Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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16
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Vera-Sigüenza E, Catalán MA, Peña-Münzenmayer G, Melvin JE, Sneyd J. A Mathematical Model Supports a Key Role for Ae4 (Slc4a9) in Salivary Gland Secretion. Bull Math Biol 2017; 80:255-282. [PMID: 29209914 DOI: 10.1007/s11538-017-0370-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 11/22/2017] [Indexed: 12/18/2022]
Abstract
We develop a mathematical model of a salivary gland acinar cell with the objective of investigating the role of two [Formula: see text] exchangers from the solute carrier family 4 (Slc4), Ae2 (Slc4a2) and Ae4 (Slc4a9), in fluid secretion. Water transport in this type of cell is predominantly driven by [Formula: see text] movement. Here, a basolateral [Formula: see text] adenosine triphosphatase pump (NaK-ATPase) and a [Formula: see text]-[Formula: see text]-[Formula: see text] cotransporter (Nkcc1) are primarily responsible for concentrating the intracellular space with [Formula: see text] well above its equilibrium potential. Gustatory and olfactory stimuli induce the release of [Formula: see text] ions from the internal stores of acinar cells, which triggers saliva secretion. [Formula: see text]-dependent [Formula: see text] and [Formula: see text] channels promote ion secretion into the luminal space, thus creating an osmotic gradient that promotes water movement in the secretory direction. The current model for saliva secretion proposes that [Formula: see text] anion exchangers (Ae), coupled with a basolateral [Formula: see text] ([Formula: see text]) (Nhe1) antiporter, regulate intracellular pH and act as a secondary [Formula: see text] uptake mechanism (Nauntofte in Am J Physiol Gastrointest Liver Physiol 263(6):G823-G837, 1992; Melvin et al. in Annu Rev Physiol 67:445-469, 2005. https://doi.org/10.1146/annurev.physiol.67.041703.084745 ). Recent studies demonstrated that Ae4 deficient mice exhibit an approximate [Formula: see text] decrease in gland salivation (Peña-Münzenmayer et al. in J Biol Chem 290(17):10677-10688, 2015). Surprisingly, the same study revealed that absence of Ae2 does not impair salivation, as previously suggested. These results seem to indicate that the Ae4 may be responsible for the majority of the secondary [Formula: see text] uptake and thus a key mechanism for saliva secretion. Here, by using 'in-silico' Ae2 and Ae4 knockout simulations, we produced mathematical support for such controversial findings. Our results suggest that the exchanger's cotransport of monovalent cations is likely to be important in establishing the osmotic gradient necessary for optimal transepithelial fluid movement.
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Affiliation(s)
- Elías Vera-Sigüenza
- Department of Mathematics, The University of Auckland, Level 2, Building 303, 38 Princes Street, Auckland CBD, New Zealand.
| | - Marcelo A Catalán
- Departamento de Ciencias Químicas y Farmacéuticas, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Gaspar Peña-Münzenmayer
- Center for Interdisciplinary Studies on the Nervous System (CISNe) and Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James Sneyd
- Department of Mathematics, The University of Auckland, Level 2, Building 303, 38 Princes Street, Auckland CBD, New Zealand
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17
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Chaban YHG, Chen Y, Hertz E, Hertz L. Severe Convulsions and Dysmyelination in Both Jimpy and Cx32/47 -/- Mice may Associate Astrocytic L-Channel Function with Myelination and Oligodendrocytic Connexins with Internodal K v Channels. Neurochem Res 2017; 42:1747-1766. [PMID: 28214987 DOI: 10.1007/s11064-017-2194-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 12/12/2022]
Abstract
The Jimpy mouse illustrates the importance of interactions between astrocytes and oligodendrocytes. It has a mutation in Plp coding for proteolipid protein and DM20. Its behavior is normal at birth but from the age of ~2 weeks it shows severe convulsions associated with oligodendrocyte/myelination deficits and early death. A normally occurring increase in oxygen consumption by highly elevated K+ concentrations is absent in Jimpy brain slices and cultured astrocytes, reflecting that Plp at early embryonic stages affects common precursors as also shown by the ability of conditioned medium from normal astrocytes to counteract histological abnormalities. This metabolic response is now known to reflect opening of L-channels for Ca2+. The resulting deficiency in Ca2+ entry has many consequences, including lack of K+-stimulated glycogenolysis and release of gliotransmitter ATP. Lack of purinergic stimulation compromises oligodendrocyte survival and myelination and affects connexins and K+ channels. Mice lacking the oligodendrocytic connexins Cx32 and 47 show similar neurological dysfunction as Jimpy. This possibly reflects that K+ released by intermodal axonal Kv channels is transported underneath a loosened myelin sheath instead of reaching the extracellular space via connexin-mediated transport to oligodendrocytes, followed by release and astrocytic Na+,K+-ATPase-driven uptake with subsequent Kir4.1-facilitated release and neuronal uptake.
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Affiliation(s)
| | - Ye Chen
- Henry M. Jackson Foundation, Bethesda, MD, 20817, USA
| | - Elna Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, People's Republic of China
| | - Leif Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, People's Republic of China.
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18
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Tolcos M, Petratos S, Hirst JJ, Wong F, Spencer SJ, Azhan A, Emery B, Walker DW. Blocked, delayed, or obstructed: What causes poor white matter development in intrauterine growth restricted infants? Prog Neurobiol 2017; 154:62-77. [PMID: 28392287 DOI: 10.1016/j.pneurobio.2017.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 03/17/2017] [Accepted: 03/29/2017] [Indexed: 12/22/2022]
Abstract
Poor white matter development in intrauterine growth restricted (IUGR) babies remains a major, untreated problem in neonatology. New therapies, guided by an understanding of the mechanisms that underlie normal and abnormal oligodendrocyte development and myelin formation, are required. Much of our knowledge of the mechanisms that underlie impaired myelination come from studies in adult demyelinating disease, preterm brain injury, or experimental models of hypoxia-ischemia. However, relatively less is known for IUGR which is surprising because IUGR is a leading cause of perinatal mortality and morbidity, second only to premature birth. IUGR is also a significant risk factor for the later development of cerebral palsy, and is a greater risk compared to some of the more traditionally researched antecedents - asphyxia and inflammation. Recent evidence suggests that the white matter injury and reduced myelination in the brains of some preterm babies is due to impaired maturation of oligodendrocytes thereby resulting in the reduced capacity to synthesize myelin. Therefore, it is not surprising that the hypomyelination observable in the central nervous system of IUGR infants has similarly lead to investigations identifying a delay or blockade in the progress of maturation of oligodendrocytes in these infants. This review will discuss current ideas thought to account for the poor myelination often present in the neonate's brain following IUGR, and discuss novel interventions that are promising as treatments that promote oligodendrocyte maturation, and thereby repair the myelination deficits that otherwise persist into infancy and childhood and lead to neurodevelopmental abnormalities.
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Affiliation(s)
- Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia.
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
| | - Jonathan J Hirst
- School of Biomedical Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Flora Wong
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia; Monash Newborn and Monash University, Clayton, Victoria, 3168, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Aminath Azhan
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia
| | - Ben Emery
- Oregon Health and Science University, Portland, OR, 97239-3098, USA
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
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19
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Hertz L, Chen Y. Importance of astrocytes for potassium ion (K+) homeostasis in brain and glial effects of K+ and its transporters on learning. Neurosci Biobehav Rev 2016; 71:484-505. [DOI: 10.1016/j.neubiorev.2016.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/12/2016] [Accepted: 09/23/2016] [Indexed: 10/20/2022]
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20
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Marinelli C, Bertalot T, Zusso M, Skaper SD, Giusti P. Systematic Review of Pharmacological Properties of the Oligodendrocyte Lineage. Front Cell Neurosci 2016; 10:27. [PMID: 26903812 PMCID: PMC4751280 DOI: 10.3389/fncel.2016.00027] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/25/2016] [Indexed: 12/12/2022] Open
Abstract
Oligodendrogenesis and oligodendrocyte precursor maturation are essential processes during the course of central nervous system development, and lead to the myelination of axons. Cells of the oligodendrocyte lineage are generated in the germinal zone from migratory bipolar oligodendrocyte precursor cells (OPCs), and acquire cell surface markers as they mature and respond specifically to factors which regulate proliferation, migration, differentiation, and survival. Loss of myelin underlies a wide range of neurological disorders, some of an autoimmune nature—multiple sclerosis probably being the most prominent. Current therapies are based on the use of immunomodulatory agents which are likely to promote myelin repair (remyelination) indirectly by subverting the inflammatory response, aspects of which impair the differentiation of OPCs. Cells of the oligodendrocyte lineage express and are capable of responding to a diverse array of ligand-receptor pairs, including neurotransmitters and nuclear receptors such as γ-aminobutyric acid, glutamate, adenosine triphosphate, serotonin, acetylcholine, nitric oxide, opioids, prostaglandins, prolactin, and cannabinoids. The intent of this review is to provide the reader with a synopsis of our present state of knowledge concerning the pharmacological properties of the oligodendrocyte lineage, with particular attention to these receptor-ligand (i.e., neurotransmitters and nuclear receptor) interactions that can influence oligodendrocyte migration, proliferation, differentiation, and myelination, and an appraisal of their therapeutic potential. For example, many promising mediators work through Ca2+ signaling, and the balance between Ca2+ influx and efflux can determine the temporal and spatial properties of oligodendrocytes (OLs). Moreover, Ca2+ signaling in OPCs can influence not only differentiation and myelination, but also process extension and migration, as well as cell death in mature mouse OLs. There is also evidence that oligodendroglia exhibit Ca2+ transients in response to electrical activity of axons for activity-dependent myelination. Cholinergic antagonists, as well as endocannabinoid-related lipid-signaling molecules target OLs. An understanding of such pharmacological pathways may thus lay the foundation to allow its leverage for therapeutic benefit in diseases of demyelination.
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Affiliation(s)
- Carla Marinelli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua Padua, Italy
| | - Thomas Bertalot
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua Padua, Italy
| | - Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua Padua, Italy
| | - Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua Padua, Italy
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua Padua, Italy
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21
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Fu P, Tang R, Yu Z, Huang S, Xie M, Luo X, Wang W. Bumetanide-induced NKCC1 inhibition attenuates oxygen-glucose deprivation-induced decrease in proliferative activity and cell cycle progression arrest in cultured OPCs via p-38 MAPKs. Brain Res 2015; 1613:110-9. [PMID: 25881895 DOI: 10.1016/j.brainres.2015.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/23/2015] [Accepted: 04/04/2015] [Indexed: 11/28/2022]
Abstract
The Na-K-Cl co-transporter 1 (NKCC1; a member of the cation-chloride co-transporter family) mediates the coupled movement of Na(+) and/or K(+) with Cl(-) across the plasma membrane of cells (Haas and Forbush, 2000, Annu. Rev. Physiol., 62, 515-534; Russell, 2000, Physiol. Rev., 80, 211-276). Although it acts as an important regulator of cell volume, secretion, and modulator of cell apoptosis and proliferation (Chen et al., 2005, J. Cereb. Blood Flow Metab., 25, 54-66; Kahle et al., 2008, Nat. Clin. Pract. Neurol., 4, 490-503; Kidokoro et al., 2014, Am. J. Physiol. Ren. Physiol., 306, F1155-F1160; Wang et al., 2011, Cell. Physiol. Biochem., 28, 703-714), NKCC1׳s effects on oligodendrocyte precursor cells (OPCs) have not been characterized. The aim of this study was to investigate whether and to what extent inhibition of NKCC1 alters oxygen glucose deprivation (OGD)-induced cell cycle progression. In the present study, we demonstrated that inhibition of NKCC1 with bumetanide attenuates the decrease in OGD-induced DNA synthesis in cultured OPCs. Western blots showed that NKCC1 inhibition led to an increased expression of cyclin D1, CDK 4, and cyclin E in OGD-treated cells. Furthermore, our results showed bumetanide attenuated the decrease in OGD-induced proliferation and arrest of cell cycle progression via the P-38 MAPK signaling cascade. Thus, NKCC1 plays important roles in the proliferation of OPCs under OGD-induced stress.
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Affiliation(s)
- Peicai Fu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
| | - Ronghua Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
| | - Zhiyuan Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan 430030, PR China
| | - Shanshan Huang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan 430030, PR China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan 430030, PR China.
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22
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Jantzie LL, Hu MY, Park HK, Jackson MC, Yu J, Maxwell JR, Jensen FE. Chloride cotransporter NKCC1 inhibitor bumetanide protects against white matter injury in a rodent model of periventricular leukomalacia. Pediatr Res 2015; 77:554-62. [PMID: 25585037 DOI: 10.1038/pr.2015.9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 10/25/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Periventricular leukomalacia (PVL) is a major form of preterm brain injury. Na(+)-K(+)-Cl(-) 1 cotransporter (NKCC1) expression on neurons and astrocytes is developmentally regulated and mediates Cl(-) reversal potential. We hypothesized that NKCC1 is highly expressed on oligodendrocytes (OLs) and increases vulnerability to hypoxia-ischemia (HI) mediated white matter injury, and that the NKCC1 inhibitor bumetanide would be protective in a rodent PVL model. METHODS Immunohistochemistry in Long-Evans rats and PLP-EGFP transgenic mice was used to establish cell-specific expression of NKCC1 in the immature rodent brain. HI was induced on postnatal day 6 (P6) in rats and the protective efficacy of bumetanide (0.3 mg/kg/i.p. q12h × 60 h) established. RESULTS NKCC1 was expressed on OLs and subplate neurons through the first 2 postnatal weeks, peaking in white matter and the subplate between P3-7. Following HI, NKCC1 is expressed on OLs and neurons. Bumetanide treatment significantly attenuates myelin basic protein loss and neuronal degeneration 7 d post-HI. CONCLUSION Presence and relative overexpression of NKCC1 in rodent cerebral cortex coincides with a period of developmental vulnerability to HI white matter injury in the immature prenatal brain. The protective efficacy of bumetanide in this model of preterm brain injury suggests that Cl(-) transport is a factor in PVL and that its inhibition may have clinical application in premature human infants.
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Affiliation(s)
- Lauren L Jantzie
- 1] Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts [2] Department of Pediatrics, University of New Mexico, Albuquerque, New Mexico
| | - Melody Y Hu
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hyun-Kyung Park
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Michele C Jackson
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jenny Yu
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jessie R Maxwell
- Department of Pediatrics, University of New Mexico, Albuquerque, New Mexico
| | - Frances E Jensen
- 1] Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts [2] Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Abstract
This review presents a brief overview of the γ-aminobutyric acid (GABA) system in the developing and mature central nervous system (CNS) and its potential connections to pathologies of the CNS. γ-aminobutyric acid (GABA) is a major neurotransmitter expressed from the embryonic stage and throughout life. At an early developmental stage, GABA acts in an excitatory manner and is implicated in many processes of neurogenesis, including neuronal proliferation, migration, differentiation, and preliminary circuit-building, as well as the development of critical periods. In the mature CNS, GABA acts in an inhibitory manner, a switch mediated by chloride/cation transporter expression and summarized in this review. GABA also plays a role in the development of interstitial neurons of the white matter, as well as in oligodendrocyte development. Although the underlying cellular mechanisms are not yet well understood, we present current findings for the role of GABA in neurological diseases with characteristic white matter abnormalities, including anoxic-ischemic injury, periventricular leukomalacia, and schizophrenia. Development abnormalities of the GABAergic system appear particularly relevant in the etiology of schizophrenia. This review also covers the potential role of GABA in mature brain injury, namely transient ischemia, stroke, and traumatic brain injury/post-traumatic epilepsy.
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Affiliation(s)
- Connie Wu
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
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24
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Disrupting MLC1 and GlialCAM and ClC-2 interactions in leukodystrophy entails glial chloride channel dysfunction. Nat Commun 2014; 5:3475. [PMID: 24647135 DOI: 10.1038/ncomms4475] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/18/2014] [Indexed: 11/08/2022] Open
Abstract
Defects in the astrocytic membrane protein MLC1, the adhesion molecule GlialCAM or the chloride channel ClC-2 underlie human leukoencephalopathies. Whereas GlialCAM binds ClC-2 and MLC1, and modifies ClC-2 currents in vitro, no functional connections between MLC1 and ClC-2 are known. Here we investigate this by generating loss-of-function Glialcam and Mlc1 mouse models manifesting myelin vacuolization. We find that ClC-2 is unnecessary for MLC1 and GlialCAM localization in brain, whereas GlialCAM is important for targeting MLC1 and ClC-2 to specialized glial domains in vivo and for modifying ClC-2's biophysical properties specifically in oligodendrocytes (OLs), the cells chiefly affected by vacuolization. Unexpectedly, MLC1 is crucial for proper localization of GlialCAM and ClC-2, and for changing ClC-2 currents. Our data unmask an unforeseen functional relationship between MLC1 and ClC-2 in vivo, which is probably mediated by GlialCAM, and suggest that ClC-2 participates in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts.
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25
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Hirst JJ, Kelleher MA, Walker DW, Palliser HK. Neuroactive steroids in pregnancy: key regulatory and protective roles in the foetal brain. J Steroid Biochem Mol Biol 2014; 139:144-53. [PMID: 23669456 DOI: 10.1016/j.jsbmb.2013.04.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 04/05/2013] [Accepted: 04/09/2013] [Indexed: 12/12/2022]
Abstract
Neuroactive steroid concentrations are remarkably high in the foetal brain during late gestation. These concentrations are maintained by placental progesterone synthesis and the interaction of enzymes in the placenta and foetal brain. 5α-Pregnane-3α-ol-20-one (allopregnanolone) is a key neuroactive steroid during foetal life, although other 3α-hydroxy-pregnanes may make an additional contribution to neuroactive steroid action. Allopregnanolone modulates GABAergic inhibition to maintain a suppressive action on the foetal brain during late gestation. This action suppresses foetal behaviour and maintains the appropriate balance of foetal sleep-like behaviours, which in turn are important to normal neurodevelopment. Neuroactive steroid-induced suppression of excitability has a key role in protecting the foetal brain from acute hypoxia/ischaemia insults. Hypoxia-induced brain injury is markedly increased if neuroactive steroid levels are suppressed and there is increased seizure activity. There is also a rapid increase in allopregnanolone synthesis and hence levels in response to acute stress that acts as an endogenous protective mechanism. Allopregnanolone has a trophic role in regulating development, maintaining normal levels of apoptosis and increasing myelination during late gestation in the brain. In contrast, chronic foetal stressors, including intrauterine growth restriction, do not increase neuroactive steroid levels in the brain and exposure to repeated synthetic corticosteroids reduce neuroactive steroid levels. The reduced availability of neuroactive steroids may contribute to the adverse effects of chronic stressors on the foetal and newborn brain. Preterm birth also deprives the foetus of neuroactive steroid mediated protection and may increase vulnerability to brain injury and suboptimal development. These finding suggest replacement therapies should be explored. This article is part of a Special Issue entitled 'Pregnancy and steroids'.
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Affiliation(s)
- Jonathan J Hirst
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia.
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26
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Ip YK, Hiong KC, Wong SZH, Ching B, Chen XL, Soh MML, Chng YR, Ong JLY, Wilson JM, Chew SF. Branchial Na(+):K(+):2Cl(-) cotransporter 1 and Na(+)/K(+)-ATPase α-subunit in a brackish water-type ionocyte of the euryhaline freshwater white-rimmed stingray, Himantura signifer. Front Physiol 2013; 4:362. [PMID: 24339817 PMCID: PMC3857534 DOI: 10.3389/fphys.2013.00362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/23/2013] [Indexed: 11/13/2022] Open
Abstract
Himantura signifer is a freshwater stingray which inhabits rivers in Southeast Asia. It can survive in brackish water but not seawater. In brackish water, it becomes partially ureosmotic, but how it maintains its plasma hypoionic to the external medium is enigmatic because of the lack of a rectal gland. Here, we report for the first time the expression of Na(+):K(+):2Cl(-) cotransporter 1 (nkcc1) in the gills of freshwaterH. signifer, and its moderate up-regulation (~2-fold) in response to brackish water (salinity 20) acclimation. The absence of the Ste20-related proline-alanine-rich kinase and oxidation stress response kinase 1 interaction site from the N-terminus of H. signifer Nkcc1 suggested that it might not be effectively activated by stress kinases in response to salinity changes as in more euryhaline teleosts. The increased activity of Nkcc1 during salt excretion in brackish water would lead to an influx of Na(+) into ionocytes, and the maintenance of intracellular Na(+) homeostasis would need the cooperation of Na(+)/K(+)-ATPase (Nka). We demonstrated for the first time the expression of nkaα1, nkaα2 and nkaα3 in the gills of H. signifer, and the up-regulation of the mRNA expression of nkaα3 and the overall protein abundance of Nkaα in response to acclimation to brackish water. Immunofluorescence microscopy revealed the presence of a sub-type of ionocyte, co-expressing Nkcc1 and Nkaα, near the base of the secondary lamellae in the gills of H. signifer acclimated to brackish water, but this type of ionocyte was absent from the gills of fish kept in fresh water. Hence, there could be a change in the function of the gills of H. signifer from salt absorption to salt excretion during brackish water acclimation in the absence of a functioning rectal gland.
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Affiliation(s)
- Yuen K Ip
- Department of Biological Sciences, National University of Singapore Singapore, Singapore
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27
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Ip YK, Hou Z, Chen XL, Ong JLY, Chng YR, Ching B, Hiong KC, Chew SF. High brain ammonia tolerance and down-regulation of Na+:K+:2Cl(-) Cotransporter 1b mRNA and protein expression in the brain of the Swamp Eel, Monopterus albus, exposed to environmental ammonia or terrestrial conditions. PLoS One 2013; 8:e69512. [PMID: 24069137 PMCID: PMC3777983 DOI: 10.1371/journal.pone.0069512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/11/2013] [Indexed: 01/19/2023] Open
Abstract
Na(+):K(+):2Cl(-) cotransporter 1 (NKCC1) has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterusalbus. Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g(-1) and 2.7 µmol g(-1) after 6 days of exposure to 50 mmol l(-1) NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance.
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Affiliation(s)
- Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Zhisheng Hou
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Xiu L. Chen
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - You R. Chng
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Biyun Ching
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, Republic of Singapore
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28
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Cesetti T, Ciccolini F, Li Y. GABA Not Only a Neurotransmitter: Osmotic Regulation by GABA(A)R Signaling. Front Cell Neurosci 2012; 6:3. [PMID: 22319472 PMCID: PMC3268181 DOI: 10.3389/fncel.2012.00003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/10/2012] [Indexed: 12/05/2022] Open
Abstract
Mature macroglia and almost all neural progenitor types express γ-aminobutyric (GABA) A receptors (GABAARs), whose activation by ambient or synaptic GABA, leads to influx or efflux of chloride (Cl−) depending on its electro-chemical gradient (ECl). Since the flux of Cl− is indissolubly associated to that of osmotically obliged water, GABAARs regulate water movements by modulating ion gradients. In addition, since water movements also occur through specialized water channels and transporters, GABAAR signaling could affect the movement of water by regulating the function of the channels and transporters involved, thereby affecting not only the direction of the water fluxes but also their dynamics. We will here review recent observations indicating that in neural cells GABAAR-mediated osmotic regulation affects the cellular volume thereby activating multiple intracellular signaling mechanisms important for cell proliferation, maturation, and survival. In addition, we will discuss evidence that the osmotic regulation exerted by GABA may contribute to brain water homeostasis in physiological and in pathological conditions causing brain edema, in which the GABAergic transmission is often altered.
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Affiliation(s)
- Tiziana Cesetti
- Department of Physiology and Pathophysiology, Interdisciplinary Center for Neurosciences, University of Heidelberg Heidelberg, Germany
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29
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Oxygen Sensitive Synaptic Neurotransmission in Anoxia-Tolerant Turtle Cerebrocortex. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 758:71-9. [DOI: 10.1007/978-94-007-4584-1_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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30
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Leiserson WM, Keshishian H. Maintenance and regulation of extracellular volume and the ion environment in Drosophila larval nerves. Glia 2011; 59:1312-21. [PMID: 21305613 DOI: 10.1002/glia.21132] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 12/01/2010] [Indexed: 11/07/2022]
Abstract
In mammals and insects, paracellular blood barriers isolate the nervous system from the rest of the animal. Glia and accessory cells of the nervous system use pumps, channels, cotransporters, and exchangers collectively to maintain the extracellular ion environment and osmotic balance in the nervous system. At present, the molecular mechanisms that regulate this process remain unclear. In humans, loss of extracellular ion and volume regulation in the nervous system poses serious health threats. Drosophila is a model genetic organism with a proven track record for uncovering molecular mechanisms relevant to human health and disease. Here, we review what is known about extracellular ion and volume regulation in larval abdominal nerves, present some new data about the impact of neural activity on the extracellular environment, and relate the findings to mammalian systems. Homologies have been found at the level of morphology, physiology, molecular mechanisms, and mutant phenotypes. The Fray-Ncc69 module regulates extracellular volume in larval nerves. Genetic rescue experiments with the mammalian orthologs prove this module has a direct correlate in humans. This and other molecular homologies, together with the similar physiological needs, suggest that uncovering the molecular mechanisms of ion and volume regulation in larval nerves will likely provide significant insights into this process in mammalian systems.
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Affiliation(s)
- William M Leiserson
- Molecular, Cellular, and Developmental Biology Department, Yale University, P.O. Box 208103, New Haven, Connecticut 06520-8103, USA.
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31
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Leiserson WM, Forbush B, Keshishian H. Drosophila glia use a conserved cotransporter mechanism to regulate extracellular volume. Glia 2011; 59:320-32. [PMID: 21125654 PMCID: PMC3005002 DOI: 10.1002/glia.21103] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The nervous system is protected by blood barriers that use multiple systems to control extracellular solute composition, osmotic pressure, and fluid volume. In the human nervous system, misregulation of the extracellular volume poses serious health threats. Here, we show that the glial cells that form the Drosophila blood-nerve barrier have a conserved molecular mechanism that regulates extracellular volume: the Serine/Threonine kinase Fray, which we previously showed is an ortholog of mammalian PASK/SPAK; and the Na-K-Cl cotransporter Ncc69, which we show is an ortholog of human NKCC1. In mammals, PASK/SPAK binds to NKCC1 and regulates its activity. In Drosophila, larvae mutant for Ncc69 develop a peripheral neuropathy, where fluid accumulates between glia and axons. The accumulation of fluid has no detectable impact on action potential conduction, suggesting that the role of Ncc69 is to maintain volume or osmotic homeostasis. Drosophila Ncc69 has kinetics similar to human NKCC1, and NKCC1 can rescue Ncc69, suggesting that they function in a conserved physiological mechanism. We show that fray and Ncc69 are coexpressed in nerve glia, interact in a yeast-two-hybrid assay, and have an essentially identical bulging nerve phenotype. We propose that normally functioning nerves generate extracellular solutes that are removed by Ncc69 under the control of Fray. This mechanism may perform a similar role in humans, given that NKCC1 is expressed at the blood-brain barrier.
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Affiliation(s)
- William M Leiserson
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, Connecticut 06520-8103, USA.
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32
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33
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Jayakumar AR, Norenberg MD. The Na-K-Cl Co-transporter in astrocyte swelling. Metab Brain Dis 2010; 25:31-8. [PMID: 20336356 DOI: 10.1007/s11011-010-9180-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
Abstract
Ion channels, exchangers and transporters are known to be involved in cell volume regulation. A disturbance in one or more of these systems may result in loss of ion homeostasis and cell swelling. In particular, activation of the Na(+)-K(+)-Cl(-) cotransporters has been shown to regulate cell volume in many conditions. The Na(+)-K(+)-Cl- cotransporters (NKCC) are a class of membrane proteins that transport Na, K, and Cl ions into and out of a wide variety of epithelial and nonepithelial cells. Studies have established the role of NKCC1 in astrocyte swelling/brain edema in ischemia and trauma. Our recent studies suggest that NKCC1 activation is also involved in astrocyte swelling induced by ammonia and in the brain edema in the thioacetamide model of acute liver failure. This review will focus on mechanisms of NKCC1 activation and its contribution to astrocyte swelling/brain edema in neurological disorders, with particular emphasis on ammonia neurotoxicity and acute liver failure.
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Affiliation(s)
- Arumugam R Jayakumar
- Department of Pathology (D-33), University of Miami Miller School of Medicine, P.O. Box 016960, Miami, FL 33125, USA.
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34
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Yamazaki Y, Hozumi Y, Kaneko K, Fujii S, Goto K, Kato H. Oligodendrocytes: facilitating axonal conduction by more than myelination. Neuroscientist 2009; 16:11-8. [PMID: 19429890 DOI: 10.1177/1073858409334425] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oligodendrocytes have received much attention in relation to neurological and psychiatric disorders. The involvement of oligodendrocytes and their myelin in normal brain functions has been suggested by many lines of evidence. The conduction velocity of action potentials along axons is dramatically increased by myelination, that is, the formation of a passive insulator. There is a growing understanding of the functional roles of ion channels and neurotransmitter receptors on oligodendrocytes, and the activity-dependent facilitative effect of oligodendrocytes on conduction velocity has been demonstrated. In this article, we summarize evidence for the ability of oligodendrocytes to monitor neuronal activity and for the facilitation of axonal conduction by oligodendrocytes by mechanisms other than myelination. We suggest the underlying mechanisms for this facilitation in relation to the morphological dynamics of myelinating processes and discuss the physiological roles of the facilitation in information processing.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Neurophysiology, Yamagata University Schoolof Medicine, Yamagata, Japan.
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35
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Lauf PK, Chimote AA, Adragna NC. Lithium fluxes indicate presence of Na-Cl cotransport (NCC) in human lens epithelial cells. Cell Physiol Biochem 2008; 21:335-46. [PMID: 18453742 DOI: 10.1159/000129627] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2008] [Indexed: 11/19/2022] Open
Abstract
During regulatory volume decrease (RVD) of human lens epithelial cells (hLECs) by clotrimazole (CTZ)-sensitive K fluxes, Na-K-2Cl cotransport (NKCC) remains active and K-Cl cotransport (KCC) inactive. To determine whether such an abnormal behavior was caused by RVD-induced cell shrinkage, NKCC was measured in the presence of either CTZ or in high K media to prevent RVD. NKCC transports RbCl + NaCl, and LiCl + KCl; thus ouabain-insensitive, bumetanide-sensitive (BS) or Cl-dependent (ClD) Rb and Li fluxes were determined in hyposmotic high NaCl media with CTZ, or in high KCl media alone, or with sulfamate (Sf) or nitrate as Cl replacement at varying Rb, Li or Cl mol fractions (MF). Unexpectedly, NKCC was inhibited by 80% with CTZ (IC(50) = 31 microM). In isosmotic (300 mOsM) K, Li influx was approximately 1/3 of Rb influx in Na, 50% lower in Sf, and bumetanide-insensitive (BI). In hypotonic (200 mOsM) K, only the ClD but not BS Li fluxes were detected. At Li MFs from 0.1-1, Li fluxes fitted a bell-shaped curve maxing at approximately 0.6 Li MF, with the BS fluxes equaling approximately 1/4 of the ClD-Li influx. The difference, i.e. the BI/ClD Li influx, saturated with increasing Li and Cl MFs, with K(ms) for Li of 11 with, and 7 mM without K, and of approximately 46 mM for Cl. Inhibition of this K-independent Li influx by thiazides was weak whilst furosemide (<100 microM) was ineffective. Reverse transcription polymerase chain reaction and Western blots verified presence of both NKCC1 and Na-Cl cotransport (NCC). In conclusion, in hyposmotic high K media, which prevents CTZ-sensitive K flux-mediated RVD in hLECs, NKCC1, though molecularly expressed, was functionally silent. However, a K-independent and moderately thiazide-sensitive ClD-Li flux, i.e. LiCC, likely occurring through NCC was detected operationally and molecularly.
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Affiliation(s)
- Peter K Lauf
- Cell Biophysics Group, Department of Pathology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA.
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36
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Rocha-González HI, Mao S, Alvarez-Leefmans FJ. Na+,K+,2Cl- cotransport and intracellular chloride regulation in rat primary sensory neurons: thermodynamic and kinetic aspects. J Neurophysiol 2008; 100:169-84. [PMID: 18385481 DOI: 10.1152/jn.01007.2007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adult primary afferent neurons are depolarized by GABA throughout their entire surface, including their somata located in dorsal root ganglia (DRG). Primary afferent depolarization (PAD) mediated by GABA released from spinal interneurons determines presynaptic inhibition, a key mechanism in somatosensory processing. The depolarization is due to Cl(-) efflux through GABA(A) channels; the outward Cl(-) gradient is generated by a Na+,K+,2Cl(-) cotransporter (NKCC) as first established in amphibians. Using fluorescence imaging microscopy we measured [Cl(-)]i and cell water volume (CWV) in dissociated rat DRG cells (P0-P21) loaded with N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide and calcein, respectively. Basal [Cl(-)]i was 44.2 +/- 1.2 mM (mean +/- SE), Cl(-) equilibrium potential (E Cl) was -27.0 +/- 0.7 mV (n = 75). This [Cl(-)]i is about four times higher than electrochemical equilibrium. On isosmotic removal of external Cl(-), cells lost Cl(-) and shrank. On returning to control solution, cells reaccumulated Cl(-) and recovered CWV. Cl(-) reaccumulation had Na+-dependent (SDC) and Na+-independent (SIC) components. The SIC stabilized at [Cl(-)]i = 13.2 +/- 1.2 mM, suggesting that it was passive (E(Cl) = -60.5 +/- 3 mV). Bumetanide blocked CWV recovery and most (65%) of the SDC (IC50 = 5.7 microM), indicating that both were mediated by NKCC. Active Cl(-) uptake fell with increasing [Cl(-)]i and became negligible when [Cl(-)]i reached basal levels. The kinetics of active Cl(-) uptake suggests a negative feedback system in which intracellular Cl(-)regulates its own influx thereby keeping [Cl(-)]i constant, above electrochemical equilibrium but below the value that would attain if NKCC reached thermodynamic equilibrium.
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Affiliation(s)
- Héctor I Rocha-González
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, Ohio 45435-0001, USA
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37
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Chen H, Kintner DB, Jones M, Matsuda T, Baba A, Kiedrowski L, Sun D. AMPA-mediated excitotoxicity in oligodendrocytes: role for Na(+)-K(+)-Cl(-) co-transport and reversal of Na(+)/Ca(2+) exchanger. J Neurochem 2007; 102:1783-1795. [PMID: 17490438 DOI: 10.1111/j.1471-4159.2007.04638.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the role of Na(+)-K(+)-Cl(-) co-transporter isoform 1 (NKCC1) and reversal of Na(+)/Ca(2+) exchanger (NCX(rev)) in glutamate-mediated excitotoxicity in oligodendrocytes obtained from rat spinal cords (postnatal day 6-8). An immunocytochemical characterization showed that these cultures express NKCC1 and Na(+)/Ca(2+) exchanger isoforms 1, 2, and 3 (NCX1, NCX2, NCX3). Exposing the cultures to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) plus cyclothiazide (CTZ) led to a transient rise in intracellular (), which was followed by a sustained overload, NKCC1 phosphorylation, and a NKCC1-mediated Na(+) influx. In the presence of a specific AMPA receptor inhibitor 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX), the AMPA/CTZ failed to elicit any changes in . The AMPA/CTZ-induced sustained rise led to mitochondrial Ca(2+) accumulation, release of cytochrome c from mitochondria, and cell death. The AMPA/CTZ-elicited increase, mitochondrial damage, and cell death were significantly reduced by inhibiting NKCC1 or NCX(rev). These data suggest that in cultured oligodendrocytes, activation of AMPA receptors leads to NKCC1 phosphorylation that enhances NKCC1-mediated Na(+) influx. The latter triggers NCX(rev) and NCX(rev)-mediated overload and compromises mitochondrial function and cellular viability.
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Affiliation(s)
- Hai Chen
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Douglas B Kintner
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Mathew Jones
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Toshio Matsuda
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Akemichi Baba
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Lech Kiedrowski
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
| | - Dandan Sun
- Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA
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Abstract
✓Cerebral edema is caused by a variety of pathological conditions that affect the brain. It is associated with two separate pathophysiological processes with distinct molecular and physiological antecedents: those related to cytotoxic (cellular) edema of neurons and astrocytes, and those related to transcapillary flux of Na+and other ions, water, and serum macromolecules. In this review, the authors focus exclusively on the first of these two processes. Cytotoxic edema results from unchecked or uncompensated influx of cations, mainly Na+, through cation channels. The authors review the different cation channels that have been implicated in the formation of cytotoxic edema of astrocytes and neurons in different pathological states. A better understanding of these molecular mechanisms holds the promise of improved treatments of cerebral edema and of the secondary injury produced by this pathological process.
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Affiliation(s)
- Danny Liang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland 21201-1595, USA
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Muñoz A, Méndez P, DeFelipe J, Alvarez-Leefmans FJ. Cation-chloride cotransporters and GABA-ergic innervation in the human epileptic hippocampus. Epilepsia 2007; 48:663-73. [PMID: 17319917 DOI: 10.1111/j.1528-1167.2007.00986.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Intracellular chloride concentration, [Cl(-)](i), determines the polarity of GABA(A)-induced neuronal Cl(-) currents. In neurons, [Cl(-)](i) is set by the activity of Na(+), K(+), 2Cl(-) cotransporters (NKCC) such as NKCC1, which physiologically accumulate Cl(-) in the cell, and Cl(-) extruding K(+), Cl(-) cotransporters like KCC2. Alterations in the balance of NKCC1 and KCC2 activity may determine the switch from hyperpolarizing to depolarizing effects of GABA, reported in the subiculum of epileptic patients with hippocampal sclerosis. We studied the expression of NKCC (putative NKCC1) and KCC2 in human normal temporal neocortex by Western blot analysis and in normal and epileptic regions of the subiculum and the hippocampus proper using immunocytochemistry. Western blot analysis revealed NKCC and KCC2 proteins in adult human neocortical membranes similar to those in rat neocortex. NKCC and KCC2 immunolabeling of pyramidal and nonpyramidal cells was found in normal and epileptic hippocampal formation. In the transition between the subiculum with sclerotic regions of CA1, known to exhibit epileptogenic activity, double immunolabeling of NKCC and KCC2 revealed that approximately 20% of the NKCC-immunoreactive neurons do not express KCC2. In these same areas some neurons were distinctly hyperinnervated by parvalbumin (PV) positive hypertrophic basket formations that innervated mostly neurons expressing NKCC (74%) and to a lesser extent NKCC-immunonegative neurons (26%). Hypertrophic basket formations also innervated KCC2-positive (76%) and -negative (24%) neurons. The data suggest that changes in the relative expression of NKCC1 and KCC2 in neurons having aberrant GABA-ergic hyperinnervation may contribute to epileptiform activity in the subicular regions adjacent to sclerotic areas of the hippocampus.
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Carter CJ. Multiple genes and factors associated with bipolar disorder converge on growth factor and stress activated kinase pathways controlling translation initiation: implications for oligodendrocyte viability. Neurochem Int 2007; 50:461-90. [PMID: 17239488 DOI: 10.1016/j.neuint.2006.11.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 11/27/2006] [Indexed: 02/06/2023]
Abstract
Famine and viral infection, as well as interferon therapy have been reported to increase the risk of developing bipolar disorder. In addition, almost 100 polymorphic genes have been associated with this disease. Several form most of the components of a phosphatidyl-inositol signalling/AKT1 survival pathway (PIK3C3, PIP5K2A, PLCG1, SYNJ1, IMPA2, AKT1, GSK3B, TCF4) which is activated by growth factors (BDNF, NRG1) and also by NMDA receptors (GRIN1, GRIN2A, GRIN2B). Various other protein products of genes associated with bipolar disorder either bind to or are affected by phosphatidyl-inositol phosphate products of this pathway (ADBRK2, HIP1R, KCNQ2, RGS4, WFS1), are associated with its constituent elements (BCR, DUSP6, FAT, GNAZ) or are downstream targets of this signalling cascade (DPYSL2, DRD3, GAD1, G6PD, GCH1, KCNQ2, NOS3, SLC6A3, SLC6A4, SST, TH, TIMELESS). A further pathway relates to endoplasmic reticulum-stress (HSPA5, XBP1), caused by problems in protein glycosylation (ALG9), growth factor receptor sorting (PIK3C3, HIP1R, SYBL1), or aberrant calcium homoeostasis (WFS1). Key processes relating to these pathways appear to be under circadian control (ARNTL, CLOCK, PER3, TIMELESS). DISC1 can also be linked to many of these pathways. The growth factor pathway promotes protein synthesis, while the endoplasmic reticulum stress pathway, and other stress pathways activated by viruses and cytokines (IL1B, TNF, Interferons), oxidative stress or starvation, all factors associated with bipolar disorder risk, shuts down protein synthesis via control of the EIF2 alpha and beta translation initiation complex. For unknown reasons, oligodendrocytes appear to be particularly prone to defects in the translation initiation complex (EIF2B) and the convergence of these environmental and genomic signalling pathways on this area might well explain their vulnerability in bipolar disorder.
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Misri S, Chimote AA, Adragna NC, Warwar R, Brown TL, Lauf PK. KCC isoforms in a human lens epithelial cell line (B3) and lens tissue extracts. Exp Eye Res 2006; 83:1287-94. [PMID: 16949074 DOI: 10.1016/j.exer.2006.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 07/12/2006] [Indexed: 11/21/2022]
Abstract
We recently reported potassium-chloride cotransporter activity in human lens epithelial B3 (HLE-B3) cells. The purpose of the present study was to demonstrate in these cells as well as in human lens tissue the potassium-chloride cotransport (KCC) isoforms by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence microscopy. Of the four KCC genes known to encode the respective proteins and their spliced variants, RT-PCR with both rat and human primers revealed the predicted cDNA fragments of KCC1, KCC3a, KCC3b, and KCC4 but not KCC2 in both HLE-B3 cells and in human lens tissue extracts from cataractous patients. Polyclonal rabbit (rb) anti-rat (rt) and anti-human (hm) antibodies against rtKCC1 and hmKCC3, respectively, and a commercially available rb-anti-mouse (ms) KCC4 antibody were used. Rb anti-rtKCC1-ECL3 [against epitopes within the large extracellular loop 3 (ECL3)] revealed a 150kDa band in HLE-B3 cells consistent with the known molecular weight of KCC1. Rb anti-hmKCC3-ECL3 yielded three bands of 150, 122 and 105kDa, evidence for the presence of KCC3a, KCC3b and possibly KCC3c isoforms. The 122 and 112kDa bands were also demonstrated by rb anti-hmKCC3-CTD [the C-terminal domain (CTD)]. Rb anti-msKCC4 antibody only showed a 100kDa band in HLE-B3 cells. In the human lens tissues, a 115kDa protein was detected with rb anti-rtKCC1-ECL3 and a 100kDa band with rb anti-msKCC4, however, no bands with rb anti-hmKCC3-ECL3 or rb anti-hmKCC3-CTD. Fluorescence microscopy revealed immunocytochemical cytoplasmic and membrane labeling of HLE-B3 cells with anti-KCC1, -KCC3 (laser confocal microscopy) and -KCC4 antibodies and a Cy3-tagged secondary antibody. Hence HLE-B3 cells expressed proteins of the KCC1, KCC3a, b, and KCC4 isoforms, whereas surgically removed cataractous lens tissue expressed only those of KCC1 and KCC4.
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Affiliation(s)
- Sandeep Misri
- Cell Biophysics Group, Boonshoft School of Medicine, Wright State University, 054 Biological Sciences Building, Dayton, OH 45435, USA
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Price TJ, Hargreaves KM, Cervero F. Protein expression and mRNA cellular distribution of the NKCC1 cotransporter in the dorsal root and trigeminal ganglia of the rat. Brain Res 2006; 1112:146-58. [PMID: 16904086 PMCID: PMC1899153 DOI: 10.1016/j.brainres.2006.07.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 06/17/2006] [Accepted: 07/05/2006] [Indexed: 11/16/2022]
Abstract
Primary afferent neurons maintain depolarizing responses to GABA into adulthood. The molecular basis for this GABAergic response appears to be the Na+K+2Cl- cotransporter NKCC1 that contributes to the maintenance of a high intracellular chloride concentration. Recently, a role for NKCC1 has been proposed in nociceptive processing which makes it timely to gain a better understanding of the distribution of NKCC1 in sensory ganglia. Here, we describe that, in the rat, NKCC1 mRNA is predominately expressed by small and medium diameter dorsal root (DRG) and trigeminal (TG) ganglion neurons. The colocalization of NKCC1 mRNA with sensory neuron population markers was assessed. In the DRG, many NKCC1 mRNA-expressing neurons colocalized peripherin (57.0+/-2.5%), calcitonin-gene-related peptide (CGRP, 39.2+/-4.4%) or TRPV1 immunoreactivity (50.0+/-1.9%) whereas only 8.7+/-1.2% were co-labeled with a marker for large diameter afferents (N52). Similarly, in the TG, NKCC1 mRNA-expressing neurons frequently colocalized peripherin (50.0+/-3.0%), CGRP (35.4+/-2.6%) or TRPV1 immunoreactivity (44.7+/-1.2%) while 14.8+/-1.3% were co-labeled with the N52 antibody. NKCC1 mRNA was also detected in satellite glial (SGCs) in both the DRG and TG. Colocalization of NKCC1 protein with the SGC marker NG2 confirmed the phenotype of these NKCC1-expressing glial cells. In contrast to in situ hybridization experiments, we did not observe NKCC1 immunoreactivity in primary afferent somata. These findings suggest that NKCC1 is expressed in anatomically appropriate cells in order to modulate GABAergic responses in nociceptive neurons. Moreover, these results suggest the possibility of a functional role of NKCC1 in the glial cells closely apposed to primary sensory afferents.
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Affiliation(s)
- Theodore J Price
- McGill University, Departments of Anesthesia and Dentistry and McGill Centre for Research on Pain, 3655 Prom Sir William Osler, Montreal, QC, Canada H3G 1Y6.
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43
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Robinson S, Li Q, Dechant A, Cohen ML. Neonatal loss of gamma-aminobutyric acid pathway expression after human perinatal brain injury. J Neurosurg 2006; 104:396-408. [PMID: 16776375 PMCID: PMC1762128 DOI: 10.3171/ped.2006.104.6.396] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Perinatal brain injury leads to chronic neurological deficits in children. Damage to the premature brain produces white matter lesions (WMLs), but the impact on cortical development is less well defined. Gamma-aminobutyric acid(GABA)ergic neurons destined for the cerebral cortex migrate through the developing white matter and form the subplate during late gestation. The authors hypothesized that GABAergic neurons are vulnerable to perinatal systemic insults in premature infants, and that damage to these neurons contributes to impaired cortical development. METHODS An immunohistochemical analysis involving markers for oligodendrocytes, GABAergic neurons, axons, and apoptosis was performed on a consecutive series of 15 human neonatal telencephalon samples obtained postmortem from infants born at 25 to 32 weeks of gestation. The tissue samples were divided into two groups based on the presence or absence of WMLs by performing routine histological analyses. The expression of GABAergic neurons was compared between the two groups by using age-matched samples. Two-tailed t-tests were used for statistical analyses. Ten infants had WMLs and five did not. Significant losses of oligodendrocytes and axons and markedly increased apoptosis were appreciated in tissue samples from the infants with WMLs. Samples from infants with WMLs also showed significant losses of glutamic acid decarboxylase-67-positive cells and calretinin-positive cells, shorter neuropeptide Y-positive neurite lengths, and losses of cells expressing GABA(A)alpha1, GABA(B)R1, and N-acetylaspartate diethylamide NR1 receptors when these factors were compared with those in samples from infants without WMLs (all p < 0.02). CONCLUSIONS In addition to oligodendrocyte loss, axonal disruption, and excess apoptosis, a significant loss of telencephalon GABAergic neuron expression was found in neonatal brains with WMLs, compared with neonates' brains without WMLs. The loss of GABAergic subplate neurons in infants with WMLs may contribute to the pathogenesis of neurological deficits in children.
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Affiliation(s)
- Shenandoah Robinson
- Department of Neurosurgery, Division of Neuropathology, University Hospitals of Cleveland, Case Research Institute, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
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44
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Wouters M, De Laet A, Donck LV, Delpire E, van Bogaert PP, Timmermans JP, de Kerchove d'Exaerde A, Smans K, Vanderwinden JM. Subtractive hybridization unravels a role for the ion cotransporter NKCC1 in the murine intestinal pacemaker. Am J Physiol Gastrointest Liver Physiol 2006; 290:G1219-27. [PMID: 16123204 DOI: 10.1152/ajpgi.00032.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the small intestine, interstitial cells of Cajal (ICC) surrounding the myenteric plexus generate the pacemaking slow waves that are essential for an efficient intestinal transit. The underlying molecular mechanisms of the slow wave are poorly known. Our aim was to identify ICC-specific genes and their function in the mouse jejunum. Suppression subtractive hybridization using two independent ICC-deficient mouse models identified 56 genes putatively downregulated in the muscularis propria compared with wild-type littermates. Differential expression was confirmed by real-time quantitative PCR for the tyrosine kinase receptor KIT, the established marker for ICC, and for the Na(+)-K(+)-2Cl(-) cotransporter (NKCC1). Immunoreactivity for NKCC1 was detected in myenteric ICC but not in the ICC population located at the deep muscular plexus. NKCC1 was also expressed in enteric neurons and mucosal crypts. Bumetanide, an NKCC1 inhibitor, reversibly affected the shape, amplitude, and frequency of the slow waves. Similar alterations were observed in NKCC1 knockout mice. These data support the hypothesis that NKCC1 expressed in myenteric ICC is involved in the mechanism of slow waves in the murine jejunum.
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Affiliation(s)
- Mira Wouters
- Laboratoire de Neurophysiology, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
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Pedersen SF, O'Donnell ME, Anderson SE, Cala PM. Physiology and pathophysiology of Na+/H+ exchange and Na+ -K+ -2Cl- cotransport in the heart, brain, and blood. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1-25. [PMID: 16484438 DOI: 10.1152/ajpregu.00782.2005] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maintenance of a stable cell volume and intracellular pH is critical for normal cell function. Arguably, two of the most important ion transporters involved in these processes are the Na+/H+ exchanger isoform 1 (NHE1) and Na+ -K+ -2Cl- cotransporter isoform 1 (NKCC1). Both NHE1 and NKCC1 are stimulated by cell shrinkage and by numerous other stimuli, including a wide range of hormones and growth factors, and for NHE1, intracellular acidification. Both transporters can be important regulators of cell volume, yet their activity also, directly or indirectly, affects the intracellular concentrations of Na+, Ca2+, Cl-, K+, and H+. Conversely, when either transporter responds to a stimulus other than cell shrinkage and when the driving force is directed to promote Na+ entry, one consequence may be cell swelling. Thus stimulation of NHE1 and/or NKCC1 by a deviation from homeostasis of a given parameter may regulate that parameter at the expense of compromising others, a coupling that may contribute to irreversible cell damage in a number of pathophysiological conditions. This review addresses the roles of NHE1 and NKCC1 in the cellular responses to physiological and pathophysiological stress. The aim is to provide a comprehensive overview of the mechanisms and consequences of stress-induced stimulation of these transporters with focus on the heart, brain, and blood. The physiological stressors reviewed are metabolic/exercise stress, osmotic stress, and mechanical stress, conditions in which NHE1 and NKCC1 play important physiological roles. With respect to pathophysiology, the focus is on ischemia and severe hypoxia where the roles of NHE1 and NKCC1 have been widely studied yet remain controversial and incompletely elucidated.
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Affiliation(s)
- S F Pedersen
- Department of Biochemistry, Institute of Molecular Biology and Physiology, University of Copenhagen, Copenhagen, Denmark.
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46
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Robinson S. Systemic prenatal insults disrupt telencephalon development: implications for potential interventions. Epilepsy Behav 2005; 7:345-63. [PMID: 16061421 PMCID: PMC1762129 DOI: 10.1016/j.yebeh.2005.06.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 06/01/2005] [Indexed: 12/15/2022]
Abstract
Infants born prematurely are prone to chronic neurologic deficits including cerebral palsy, epilepsy, cognitive delay, behavioral problems, and neurosensory impairments. In affected children, imaging and neuropathological findings demonstrate significant damage to white matter. The extent of cortical damage has been less obvious. Advances in the understanding of telencephalon development provide insights into how systemic intrauterine insults affect the developing white matter, subplate, and cortex, and lead to multiple neurologic impairments. In addition to white matter oligodendrocytes and axons, other elements at risk for perinatal brain injury include subplate neurons, GABAergic neurons migrating through white matter and subplate, and afferents of maturing neurotransmitter systems. Common insults including hypoxia-ischemia and infection often affect the developing brain differently than the mature brain, and insults precipitate a cascade of damage to multiple neural lineages. Insights from development can identify potential targets for therapies to repair the damaged neonatal brain before it has matured.
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Affiliation(s)
- Shenandoah Robinson
- Pediatric Neurosurgery, Rainbow Babies and Children's Hospital, Case Research Institute, Case School of Medicine, Cleveland, OH, USA.
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47
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Abstract
The electroneutral Na-K-Cl co-transporter (NKCC) protein transports Na(+), K(+) and Cl(-) into cells under physiological conditions with a stoichiometry of 1Na(+) :1K(+) :2Cl(-). NKCC is characteristically inhibited by the sulfamoylbenzoic acid "loop'' diuretics, such as bumetanide and furosemide. To date, only two distinct isoforms, NKCC1 and NKCC2, have been identified. NKCC1 has a broad tissue distribution, while the NKCC2 isoform is only found in vertebrate kidney. NKCC serves multiple functions, including ion and fluid movements in secreting or reabsorbing epithelia and cell volume regulation. However, understanding the role of NKCC1 in the central nervous system has just begun. NKCC1 protein is expressed in neurons throughout the brain. Dendritic localization of NKCC1 is found in both pyramidal and non-pyramidal neurons. NKCC1 is important in the maintenance of intracellular Cl(-) in neurons and contributes to GABA-mediated depolarization in immature neurons. Thus, NKCC1 may affect neuronal excitability through regulation of intracellular Cl(-) concentration. Expression of NKCC1 protein has also been found in astrocytes and oligodendrocytes. In addition to its role in the accumulation of Cl(-), NKCC1 may also contribute to K(+) clearance and maintenance of intracellular Na(+) in glia. Our recent studies suggest that NKCC1 activation leads to high [K(+)](o(-)) induced astrocyte swelling and glutamate release, as well as neuronal Na(+) , and Cl(-) influx during acute excitotoxicity. Inhibition of NKCC1 activity significantly reduces infarct volume and cerebral edema following cerebral focal ischemia.
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Affiliation(s)
- Hai Chen
- Neuroscience Training Program, Department of Neurosurgery, University of Wisconsin Medical School, 332 Clinical Sciences Center, 600 Highland Avenue, Madison, WI 53792, USA
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48
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Lenart B, Kintner DB, Shull GE, Sun D. Na-K-Cl cotransporter-mediated intracellular Na+ accumulation affects Ca2+ signaling in astrocytes in an in vitro ischemic model. J Neurosci 2005; 24:9585-97. [PMID: 15509746 PMCID: PMC6730155 DOI: 10.1523/jneurosci.2569-04.2004] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Na-K-Cl cotransporter isoform 1 (NKCC1) plays an important role in maintenance of intracellular Na+, K+, and Cl- levels in astrocytes. We propose that NKCC1 may contribute to perturbations of ionic homeostasis in astrocytes under ischemic conditions. After 3-8 hr of oxygen and glucose deprivation (OGD), NKCC1-mediated 86Rb influx was significantly increased in astrocytes from NKCC1 wild-type (NKCC1+/+) and heterozygous mutant (NKCC1+/-) mice. Phosphorylated NKCC1 protein was increased in NKCC1+/+ astrocytes at 2 hr of OGD. Two hours of OGD and 1 hr of reoxygenation (OGD/REOX) triggered an 3.6-fold increase in intracellular Na+ concentration ([Na+]i) in NKCC1+/+ astrocytes. Inhibition of NKCC1 activity by bumetanide or ablation of the NKCC1 gene significantly attenuated the rise in [Na+]i. Moreover, NKCC1+/+ astrocytes swelled by 10-30% during 20-60 min of OGD. Either genetic ablation of NKCC1 or inhibition of NKCC1 by bumetanide-attenuated OGD-mediated swelling. An NKCC1-mediated increase in [Na+]i may subsequently affect Ca2+ signaling through the Na+/Ca2+ exchanger (NCX). A rise in [Ca2+]i was detected after OGD/REOX in the presence of a sarcoplasmic-endoplasmic reticulum (ER) Ca2+-ATPase inhibitor thapsigargin. Moreover, OGD/REOX led to a significant increase in Ca2+ release from ER Ca2+ stores. Furthermore, KB-R7943 (2-[2-[4(4-nitrobenzyloxy)phenyl]ethyl]isothiourea mesylate), an inhibitor of reverse-mode operation of NCX, abolished the OGD/REOX-induced enhancement in filling of ER Ca2+ stores. OGD/REOX-mediated Ca2+ accumulation in ER Ca2+ stores was absent when NKCC1 activity was ablated or pharmacologically inhibited. These findings imply that stimulation of NKCC1 activity leads to Na+ accumulation after OGD/REOX and that subsequent reverse-mode operation of NCX contributes to increased Ca2+ accumulation by intracellular Ca2+ stores.
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Affiliation(s)
- Brett Lenart
- Department of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin 53792, USA
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Nakamura NH, Rosell DR, Akama KT, McEwen BS. Estrogen and ovariectomy regulate mRNA and protein of glutamic acid decarboxylases and cation-chloride cotransporters in the adult rat hippocampus. Neuroendocrinology 2005; 80:308-23. [PMID: 15677881 DOI: 10.1159/000083657] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 10/28/2004] [Indexed: 12/22/2022]
Abstract
17beta-Estradiol spatiotemporally regulates the gamma-aminobutyric acid (GABAergic) tone in the adult hippocampus. However, the complex estrogenic effect on the GABAergic system is still unclear. In adult central nervous system (CNS) neurons, GABA can induce both inhibitory and excitatory actions, which are predominantly controlled by the cation-chloride cotransporters NKCC1 and KCC2. We therefore studied the estrogenic regulation of two glutamate decarboxylase (GAD) isoforms, GAD65 and GAD67, as well as NKCC1 and KCC2 in the adult female rat hippocampus by immunohistochemistry and in situ hybridization. First, we focused on the duration after ovariectomy (OVX) and its effects on GAD65 protein levels. The basal number of GAD65-immunoreactive cells decreased after long-term (10 days) OVX compared to short-term (3 days) OVX. We found that, only after long-term OVX but not after short-term OVX, estradiol increased the number of GAD65-immunoreactive cells in the CA1 pyramidal cell layer. Furthermore, estradiol did not alter the GAD65-immunoreactive cell population in any other CA1 subregion. Second, we therefore focused on long-term OVX and the estrogenic regulation of GAD and cation-chloride cotransporter mRNA levels. In the pyramidal cell layer, estradiol affected GAD65, GAD67 and NKCC1 mRNA levels, but not KCC2 mRNA levels. Both GAD65 and NKCC1 mRNA levels increased within 24 h after estradiol treatment, followed by a subsequent increase in GAD67 mRNA levels. These findings suggest that basal levels of estrogen might contribute to a balance between the excitatory and inhibitory synaptic transmission onto CA1 pyramidal cells by regulating perisomatic GAD and NKCC1 expression in the adult hippocampus.
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Affiliation(s)
- Nozomu H Nakamura
- Laboratory of Neuroendocrinology, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
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