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Fuse S, Fujisawa H, Murao N, Iwata N, Watanabe T, Seino Y, Takeuchi H, Suzuki A, Sugimura Y. Effects of hypernatremia on the microglia. Peptides 2024; 179:171267. [PMID: 38908517 DOI: 10.1016/j.peptides.2024.171267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 06/07/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Signs and symptoms of hypernatremia largely indicate central nervous system dysfunction. Acute hypernatremia can cause demyelinating lesions similar to that observed in osmotic demyelination syndrome (ODS). We have previously demonstrated that microglia accumulate in ODS lesions and minocycline protects against ODS by inhibiting microglial activation. However, the direct effect of rapid rise in the sodium concentrations on microglia is largely unknown. In addition, the effect of chronic hypernatremia on microglia also remains elusive. Here, we investigated the effects of acute (6 or 24 h) and chronic (the extracellular sodium concentration was increased gradually for at least 7 days) high sodium concentrations on microglia using the microglial cell line, BV-2. We found that both acute and chronic high sodium concentrations increase NOS2 expression and nitric oxide (NO) production. We also demonstrated that the expression of nuclear factor of activated T-cells-5 (NFAT5) is increased by high sodium concentrations. Furthermore, NFAT5 knockdown suppressed NOS2 expression and NO production. We also demonstrated that high sodium concentrations decreased intracellular Ca2+ concentration and an inhibitor of Na+/Ca2+ exchanger, NCX, suppressed a decrease in intracellular Ca2+ concentrations and NOS2 expression and NO production induced by high sodium concentrations. Furthermore, minocycline inhibited NOS2 expression and NO production induced by high sodium concentrations. These in vitro data suggest that microglial activity in response to high sodium concentrations is regulated by NFAT5 and Ca2+ efflux through NCX and is suppressed by minocycline.
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Affiliation(s)
- Sachiho Fuse
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Haruki Fujisawa
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Naoya Murao
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Naoko Iwata
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Takashi Watanabe
- Division of Gene Regulation, Oncology Innovation Center, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Yusuke Seino
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Hideyuki Takeuchi
- Department of Neurology and Stroke Medicine, Graduate School of Medicine, Yokohama City University, Yokohama, Kanagawa 236-0004, Japan; Department of Neurology, Graduate School of Medicine, International University of Health and Welfare, Narita, Chiba 286-8686, Japan; Center for Intractable Neurological Diseases and Dementia, International University of Health and Welfare Atami Hospital, Atami, Shizuoka 413-0012, Japan
| | - Atsushi Suzuki
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Yoshihisa Sugimura
- Department of Endocrinology, Diabetes and Metabolism, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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Dong Y, Yu Z, Li Y, Huang B, Bai Q, Gao Y, Chen Q, Li N, He L, Zhao Y. Structural insight into the allosteric inhibition of human sodium-calcium exchanger NCX1 by XIP and SEA0400. EMBO J 2024; 43:14-31. [PMID: 38177313 PMCID: PMC10897212 DOI: 10.1038/s44318-023-00013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 01/06/2024] Open
Abstract
Sodium-calcium exchanger proteins influence calcium homeostasis in many cell types and participate in a wide range of physiological and pathological processes. Here, we elucidate the cryo-EM structure of the human Na+/Ca2+ exchanger NCX1.3 in the presence of a specific inhibitor, SEA0400. Conserved ion-coordinating residues are exposed on the cytoplasmic face of NCX1.3, indicating that the observed structure is stabilized in an inward-facing conformation. We show how regulatory calcium-binding domains (CBDs) assemble with the ion-translocation transmembrane domain (TMD). The exchanger-inhibitory peptide (XIP) is trapped within a groove between the TMD and CBD2 and predicted to clash with gating helices TMs1/6 at the outward-facing state, thus hindering conformational transition and promoting inactivation of the transporter. A bound SEA0400 molecule stiffens helix TM2ab and affects conformational rearrangements of TM2ab that are associated with the ion-exchange reaction, thus allosterically attenuating Ca2+-uptake activity of NCX1.3.
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Affiliation(s)
- Yanli Dong
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhuoya Yu
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yue Li
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Huang
- Beijing StoneWise Technology Co Ltd., 15 Haidian street, Haidian district, Beijing, China
| | - Qinru Bai
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiwei Gao
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qihao Chen
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Na Li
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Lingli He
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yan Zhao
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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3
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Takei GL, Ogura Y, Ujihara Y, Toyama F, Hayashi K, Fujita T. Hamster Sperm Possess Functional Na +/Ca 2+-Exchanger 1: Its Implication in Hyperactivation. Int J Mol Sci 2023; 24:ijms24108905. [PMID: 37240252 DOI: 10.3390/ijms24108905] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Previous studies demonstrated that hamster sperm hyperactivation is suppressed by extracellular Na+ by lowering intracellular Ca2+ levels, and Na+/Ca2+-exchanger (NCX) specific inhibitors canceled the suppressive effects of extracellular Na+. These results suggest the involvement of NCX in the regulation of hyperactivation. However, direct evidence of the presence and functionality of NCX in hamster spermatozoa is still lacking. This study aimed to reveal that NCX is present and is functional in hamster spermatozoa. First, NCX1 and NCX2 transcripts were detected via RNA-seq analyses of hamster testis mRNAs, but only the NCX1 protein was detected. Next, NCX activity was determined by measuring the Na+-dependent Ca2+ influx using the Ca2+ indicator Fura-2. The Na+-dependent Ca2+ influx was detected in hamster spermatozoa, notably in the tail region. The Na+-dependent Ca2+ influx was inhibited by the NCX inhibitor SEA0400 at NCX1-specific concentrations. NCX1 activity was reduced after 3 h of incubation in capacitating conditions. These results, together with authors' previous study, showed that hamster spermatozoa possesses functional NCX1 and that its activity was downregulated upon capacitation to trigger hyperactivation. This is the first study to successfully reveal the presence of NCX1 and its physiological function as a hyperactivation brake.
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Affiliation(s)
- Gen L Takei
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
| | - Yuhei Ogura
- Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yoshihiro Ujihara
- Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Fubito Toyama
- School of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya 321-8585, Japan
| | - Keitaro Hayashi
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
| | - Tomoe Fujita
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
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Wang HT, Miyairi S, Kitamura M, Iizuka K, Asano Y, Yoshimura T, Kon N. Real time monitoring of cold Ca 2+ dependent transcription and its modulation by NCX inhibitors. Sci Rep 2022; 12:17325. [PMID: 36243739 PMCID: PMC9569354 DOI: 10.1038/s41598-022-22166-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/11/2022] [Indexed: 01/10/2023] Open
Abstract
Real-time monitoring of cellular temperature responses is an important technique in thermal biology and drug development. Recent study identified that Na+/Ca2+ exchanger (NCX)-dependent Ca2+ influx transduces cold signals to circadian clock in mammalian cultured cells. The finding raised an idea that cellular responses to the cold signals can be analyzed by monitoring of clock gene expression. We found that Per1 and Per2 were up-regulated after culture at 27 °C compared to 37 °C in Rat-1 fibroblasts. In order to monitor cold-Ca2+-dependent transcription in living cells, we developed a luciferase-based real-time reporting system by using Per1 promoter, Per2 promoter, Ca2+/cAMP-response elements (CRE) or NFAT-binding elements. We found that benzyloxyphenyl NCX inhibitor KB-R7943 and SN-6, but not SEA-0400 or YM-244769 inhibited the cold induction of Per2. Our study established a real-time monitoring system for cold Ca2+ signaling which can be applied to evaluation of drugs.
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Affiliation(s)
- Hsin-tzu Wang
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biological Science, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Shiori Miyairi
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Miho Kitamura
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Kosuke Iizuka
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Yoshimasa Asano
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Science, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Takashi Yoshimura
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Naohiro Kon
- grid.27476.300000 0001 0943 978XInstitute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,grid.27476.300000 0001 0943 978XLaboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan ,Suntory Rising Stars Encouragement Program in Life Sciences (SunRiSE), 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto, 619-0284 Japan
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5
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Meyer DJ, Díaz-García CM, Nathwani N, Rahman M, Yellen G. The Na +/K + pump dominates control of glycolysis in hippocampal dentate granule cells. eLife 2022; 11:e81645. [PMID: 36222651 PMCID: PMC9592084 DOI: 10.7554/elife.81645] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cellular ATP that is consumed to perform energetically expensive tasks must be replenished by new ATP through the activation of metabolism. Neuronal stimulation, an energetically demanding process, transiently activates aerobic glycolysis, but the precise mechanism underlying this glycolysis activation has not been determined. We previously showed that neuronal glycolysis is correlated with Ca2+ influx, but is not activated by feedforward Ca2+ signaling (Díaz-García et al., 2021a). Since ATP-powered Na+ and Ca2+ pumping activities are increased following stimulation to restore ion gradients and are estimated to consume most neuronal ATP, we aimed to determine if they are coupled to neuronal glycolysis activation. By using two-photon imaging of fluorescent biosensors and dyes in dentate granule cell somas of acute mouse hippocampal slices, we observed that production of cytoplasmic NADH, a byproduct of glycolysis, is strongly coupled to changes in intracellular Na+, while intracellular Ca2+ could only increase NADH production if both forward Na+/Ca2+ exchange and Na+/K+ pump activity were intact. Additionally, antidromic stimulation-induced intracellular [Na+] increases were reduced >50% by blocking Ca2+ entry. These results indicate that neuronal glycolysis activation is predominantly a response to an increase in activity of the Na+/K+ pump, which is strongly potentiated by Na+ influx through the Na+/Ca2+ exchanger during extrusion of Ca2+ following stimulation.
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Affiliation(s)
- Dylan J Meyer
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | | | - Nidhi Nathwani
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Mahia Rahman
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
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6
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Rodrigues T, Piccirillo S, Magi S, Preziuso A, Dos Santos Ramos V, Serfilippi T, Orciani M, Maciel Palacio Alvarez M, Luis Dos Santos Tersariol I, Amoroso S, Lariccia V. Control of Ca 2+ and metabolic homeostasis by the Na +/Ca 2+ exchangers (NCXs) in health and disease. Biochem Pharmacol 2022; 203:115163. [PMID: 35803319 DOI: 10.1016/j.bcp.2022.115163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022]
Abstract
Spatial and temporal control of calcium (Ca2+) levels is essential for the background rhythms and responses of living cells to environmental stimuli. Whatever other regulators a given cellular activity may have, localized and wider scale Ca2+ events (sparks, transients, and waves) are hierarchical determinants of fundamental processes such as cell contraction, excitability, growth, metabolism and survival. Different cell types express specific channels, pumps and exchangers to efficiently generate and adapt Ca2+ patterns to cell requirements. The Na+/Ca2+ exchangers (NCXs) in particular contribute to Ca2+ homeostasis by buffering intracellular Ca2+ loads according to the electrochemical gradients of substrate ions - i.e., Ca2+ and sodium (Na+) - and under a dynamic control of redundant regulatory processes. An interesting feature of NCX emerges from the strict relationship that connects transporter activity with cell metabolism: on the one hand NCX operates under constant control of ATP-dependent regulatory processes, on the other hand the ion fluxes generated through NCX provide mechanistic support for the Na+-driven uptake of glutamate and Ca2+ influx to fuel mitochondrial respiration. Proof of concept evidence highlights therapeutic potential of preserving a timed and balanced NCX activity in a growing rate of diseases (including excitability, neurodegenerative, and proliferative disorders) because of an improved ability of stressed cells to safely maintain ion gradients and mitochondrial bioenergetics. Here, we will summarize and review recent works that have focused on the pathophysiological roles of NCXs in balancing the two-way relationship between Ca2+ signals and metabolism.
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Affiliation(s)
- Tiago Rodrigues
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP, Brazil.
| | - Silvia Piccirillo
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Simona Magi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Alessandra Preziuso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vyctória Dos Santos Ramos
- Interdisciplinary Center for Biochemistry Investigation (CIIB), University of Mogi das Cruzes (UMC), Mogi das Cruzes, SP, Brazil
| | - Tiziano Serfilippi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Monia Orciani
- Department of Clinical and Molecular Sciences, Histology, University "Politecnica delle Marche", Ancona, Italy.
| | - Marcela Maciel Palacio Alvarez
- Department of Biochemistry, São Paulo School of Medicine, Federal University of São Paulo (Unifesp) São Paulo, SP, Brazil
| | | | - Salvatore Amoroso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vincenzo Lariccia
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
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7
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Pharmacological Dissection of the Crosstalk between Na V and Ca V Channels in GH3b6 Cells. Int J Mol Sci 2022; 23:ijms23020827. [PMID: 35055012 PMCID: PMC8775721 DOI: 10.3390/ijms23020827] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 02/01/2023] Open
Abstract
Thanks to the crosstalk between Na+ and Ca2+ channels, Na+ and Ca2+ homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, we investigated the impact of persistent activation of voltage-gated Na+ (NaV) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca2+ concentration ([Ca2+]i) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na+-Ca2+ homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the NaV1.3 channel subtype, which likely endorses their voltage-activated Na+ currents. Notably, these Na+ currents were blocked by ICA-121431 and activated by the β-scorpion toxin Tf2, two selective NaV1.3 channel ligands. Using Fura-2, we showed that VTD induced a [Ca2+]i increase. This effect was suppressed by the selective NaV channel blocker tetrodotoxin, as well by the selective L-type CaV channel (LTCC) blocker nifedipine. We also evidenced that crobenetine, a NaV channel blocker, abolished VTD-induced [Ca2+]i elevation, while it had no effects on LTCC. Altogether, our findings highlight a crosstalk between NaV and LTCC in GH3b6 cells, providing a new insight into the mode of action of neurotoxins.
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8
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Takeuchi A, Matsuoka S. Minor contribution of NCX to Na +-Ca 2+ exchange activity in brain mitochondria. Cell Calcium 2021; 96:102386. [PMID: 33706218 DOI: 10.1016/j.ceca.2021.102386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/19/2021] [Accepted: 02/25/2021] [Indexed: 11/19/2022]
Abstract
NCLX was identified as a mitochondrial Na+-Ca2+ exchanger. However, contribution of NCLX to overall mitochondrial Na+-Ca2+ exchange activity remains unclear, especially in brain mitochondria where plasma membrane Na+-Ca2+ exchanger NCX also exists. We studied the issue using isolated mouse brain mitochondria. The Na+- as well as Li+-dependent Ca2+ efflux from mitochondria was significantly inhibited by a NCLX blocker, but was insensitive to NCX blockers, suggesting that NCLX comprises a major part in forward mode of mitochondrial Na+-Ca2+ exchange activity. On the other hand, the Na+-dependent Ca2+ influx into mitochondria, the reverse mode, was insensitive to all the blockers tested, suggesting unidentified Ca2+ transport systems.
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Affiliation(s)
- Ayako Takeuchi
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, and Life Science Innovation Center, University of Fukui, Fukui 910-1193, Japan.
| | - Satoshi Matsuoka
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, and Life Science Innovation Center, University of Fukui, Fukui 910-1193, Japan
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9
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Drug development in targeting ion channels for brain edema. Acta Pharmacol Sin 2020; 41:1272-1288. [PMID: 32855530 PMCID: PMC7609292 DOI: 10.1038/s41401-020-00503-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/02/2020] [Indexed: 12/18/2022] Open
Abstract
Cerebral edema is a pathological hallmark of various central nervous system (CNS) insults, including traumatic brain injury (TBI) and excitotoxic injury such as stroke. Due to the rigidity of the skull, edema-induced increase of intracranial fluid significantly complicates severe CNS injuries by raising intracranial pressure and compromising perfusion. Mortality due to cerebral edema is high. With mortality rates up to 80% in severe cases of stroke, it is the leading cause of death within the first week. Similarly, cerebral edema is devastating for patients of TBI, accounting for up to 50% mortality. Currently, the available treatments for cerebral edema include hypothermia, osmotherapy, and surgery. However, these treatments only address the symptoms and often elicit adverse side effects, potentially in part due to non-specificity. There is an urgent need to identify effective pharmacological treatments for cerebral edema. Currently, ion channels represent the third-largest target class for drug development, but their roles in cerebral edema remain ill-defined. The present review aims to provide an overview of the proposed roles of ion channels and transporters (including aquaporins, SUR1-TRPM4, chloride channels, glucose transporters, and proton-sensitive channels) in mediating cerebral edema in acute ischemic stroke and TBI. We also focus on the pharmacological inhibitors for each target and potential therapeutic strategies that may be further pursued for the treatment of cerebral edema.
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10
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Nagata A, Tagashira H, Kita S, Kita T, Nakajima N, Abe K, Iwasaki A, Iwamoto T. Genetic knockout and pharmacologic inhibition of NCX1 attenuate hypoxia-induced pulmonary arterial hypertension. Biochem Biophys Res Commun 2020; 529:793-798. [PMID: 32736709 DOI: 10.1016/j.bbrc.2020.06.045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 11/30/2022]
Abstract
The Na+/Ca2+ exchanger type-1 (NCX1) is a bidirectional transporter that is controlled by membrane potential and transmembrane gradients of Na+ and Ca2+. Vascular smooth muscle NCX1 plays an important role in intracellular Ca2+ homeostasis and Ca2+ signaling. We found that NCX1 was upregulated in the pulmonary arteries of mice exposed to chronic hypoxia (10% O2 for 4 weeks). Hence, we investigated the pathophysiological role of NCX1 in hypoxia-induced pulmonary arterial hypertension (PAH), using NCX1-heterozygous (NCX1+/-) mice, in which NCX1 expression is reduced by half, and SEA0400, a specific NCX1 inhibitor. NCX1+/- mice exhibited attenuation of hypoxia-induced PAH and right ventricular (RV) hypertrophy compared with wild-type mice. Furthermore, continuous administration of SEA0400 (0.5 mg/kg/day for 4 weeks) to wild-type mice by osmotic pumps significantly suppressed hypoxia-induced PAH and pulmonary vessel muscularization, with a slight reduction in RV hypertrophy. These findings indicate that the upregulation of NCX1 contributes to the development of hypoxia-induced PAH, suggesting that NCX1 inhibition might be a novel approach for the treatment of PAH.
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Affiliation(s)
- Asahi Nagata
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Department of General Thoracic, Breast and Pediatric Surgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Hideaki Tagashira
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Satomi Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
| | - Tomo Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Naoko Nakajima
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Kohtaro Abe
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Akinori Iwasaki
- Department of General Thoracic, Breast and Pediatric Surgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
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11
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Shoda W, Nomura N, Ando F, Tagashira H, Iwamoto T, Ohta A, Isobe K, Mori T, Susa K, Sohara E, Rai T, Uchida S. Sodium-calcium exchanger 1 is the key molecule for urinary potassium excretion against acute hyperkalemia. PLoS One 2020; 15:e0235360. [PMID: 32603346 PMCID: PMC7326190 DOI: 10.1371/journal.pone.0235360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 06/13/2020] [Indexed: 02/07/2023] Open
Abstract
The sodium (Na+)-chloride cotransporter (NCC) expressed in the distal convoluted tubule (DCT) is a key molecule regulating urinary Na+ and potassium (K+) excretion. We previously reported that high-K+ load rapidly dephosphorylated NCC and promoted urinary K+ excretion in mouse kidneys. This effect was inhibited by calcineurin (CaN) and calmodulin inhibitors. However, the detailed mechanism through which high-K+ signal results in CaN activation remains unknown. We used Flp-In NCC HEK293 cells and mice to evaluate NCC phosphorylation. We analyzed intracellular Ca2+ concentration ([Ca2+]in) using live cell Ca2+ imaging in HEK293 cells. We confirmed that high-K+-induced NCC dephosphorylation was not observed without CaN using Flp-In NCC HEK29 cells. Extracellular Ca2+ reduction with a Ca2+ chelator inhibited high-K+-induced increase in [Ca2+]in and NCC dephosphorylation. We focused on Na+/Ca2+ exchanger (NCX) 1, a bidirectional regulator of cytosolic Ca2+ expressed in DCT. We identified that NCX1 suppression with a specific inhibitor (SEA0400) or siRNA knockdown inhibited K+-induced increase in [Ca2+]in and NCC dephosphorylation. In a mouse study, SEA0400 treatment inhibited K+-induced NCC dephosphorylation. SEA0400 reduced urinary K+ excretion and induced hyperkalemia. Here, we identified NCX1 as a key molecule in urinary K+ excretion promoted by CaN activation and NCC dephosphorylation in response to K+ load.
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Affiliation(s)
- Wakana Shoda
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Naohiro Nomura
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
- * E-mail:
| | - Fumiaki Ando
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Hideaki Tagashira
- Department of pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takahiro Iwamoto
- Department of pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Akihito Ohta
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Kiyoshi Isobe
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Koichiro Susa
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Tatemitsu Rai
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
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12
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Annunziato L, Secondo A, Pignataro G, Scorziello A, Molinaro P. New perspectives for selective NCX activators in neurodegenerative diseases. Cell Calcium 2020; 87:102170. [PMID: 32106022 DOI: 10.1016/j.ceca.2020.102170] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 11/16/2022]
Abstract
The Na+/Ca2+ exchanger plays a relevant role in several neurological disorders, thus the pharmacological modulation of its isoforms might represent a promising strategy to ameliorate the course of some neurological pathologies including stroke, neonatal hypoxia, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer Disease (AD), and spinal muscular atrophy (SMA). This review will summarize heterocyclic, peptidergic, genetic and epigenetic compounds activating or inhibiting the expression/activity of each NCX isoform. In addition, we will focus our attention on the development of new strategies aimed to ameliorate the pathophysiological conditions in which NCX isoform changes are found.
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Affiliation(s)
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, "Federico II" University of Naples, 80131 Naples, Italy.
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, "Federico II" University of Naples, 80131 Naples, Italy.
| | - Antonella Scorziello
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, "Federico II" University of Naples, 80131 Naples, Italy.
| | - Pasquale Molinaro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, "Federico II" University of Naples, 80131 Naples, Italy.
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13
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Lariccia V, Macrì ML, Matteucci A, Maiolino M, Amoroso S, Magi S. Effects of ticagrelor on the sodium/calcium exchanger 1 (NCX1) in cardiac derived H9c2 cells. Eur J Pharmacol 2019; 850:158-166. [PMID: 30721704 DOI: 10.1016/j.ejphar.2019.01.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/08/2019] [Accepted: 01/17/2019] [Indexed: 12/15/2022]
Abstract
Ticagrelor is a direct acting and reversibly binding P2Y12 antagonist approved for the prevention of thromboembolic events. Clinical effects of ticagrelor cannot be simply accounted for by pure platelet inhibition, and off-target mechanisms can potentially play a role. In particular, recent evidence suggests that ticagrelor may also influence heart function and improve the evolution of myocardial ischemic injury by more direct effects on myocytes. The cardiac sodium/calcium exchanger 1 (NCX1) is a critical player in the generation and control of calcium (Ca2+) signals, which orchestrate multiple myocyte activities in health and disease. Altered expression and/or activity of NCX1 can have profound consequences for the function and fate of myocytes. Whether ticagrelor affects cardiac NCX1 has not been investigated yet. To explore this hypothesis, we analyzed the expression, localization and activity of NCX1 in the heart derived H9c2-NCX1 cells following ticagrelor exposure. We found that ticagrelor concentration- and time-dependently reduced the activity of the cardiac NCX1 in H9c2 cells. In particular, the inhibitory effect of ticagrelor on the Ca2+-influx mode of NCX1 was evident within 1 h and further developed after 24 h, when NCX1 activity was suppressed by about 55% in cells treated with 1 μM ticagrelor. Ticagrelor-induced inhibition of exchanger activity was reached at clinically relevant concentrations, without affecting the expression levels and subcellular distribution of NCX1. Collectively, these findings suggest that cardiac NCX1 is a new downstream target of ticagrelor, which may contribute to the therapeutic profile of ticagrelor in clinical practice.
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Affiliation(s)
- Vincenzo Lariccia
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy.
| | - Maria Loredana Macrì
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy
| | - Alessandra Matteucci
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy
| | - Marta Maiolino
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy
| | - Salvatore Amoroso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy
| | - Simona Magi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Via Tronto 10/A, 60126 Ancona, Italy
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14
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Halty-deLeon L, Hansson BS, Wicher D. The Drosophila melanogaster Na +/Ca 2+ Exchanger CALX Controls the Ca 2+ Level in Olfactory Sensory Neurons at Rest and After Odorant Receptor Activation. Front Cell Neurosci 2018; 12:186. [PMID: 30018538 PMCID: PMC6038709 DOI: 10.3389/fncel.2018.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/11/2018] [Indexed: 11/13/2022] Open
Abstract
CALX, the Na+/Ca2+ exchanger in Drosophila, is highly expressed in the outer dendrites of olfactory sensory neurons (OSNs) which are equipped with the odorant receptors (ORs). Insect OR/Orco dimers are nonselective cation channels that pass also calcium which leads to elevated calcium levels after OR activation. CALX exhibits an anomalous regulation in comparison to its homolog in mammals sodium/calcium exchanger, NCX: it is inhibited by increasing intracellular calcium concentration [Ca2+]i. Thus, CALX mediates only Ca2+ efflux, not influx. The main goal of this study was to elucidate a possible role of this protein in the olfactory response. We first asked whether already described NCX inhibitors were capable of blocking CALX. By means of calcium imaging techniques in ex-vivo preparations and heterologous expression systems, we determined ORM-10962 as a potent CALX inhibitor. CALX inhibition did not affect the odor response but it affected the recovery of the calcium level after this response. In addition, CALX controls the calcium level of OSNs at rest.
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Affiliation(s)
- Lorena Halty-deLeon
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
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15
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Lillo MA, Gaete PS, Puebla M, Ardiles NM, Poblete I, Becerra A, Simon F, Figueroa XF. Critical contribution of Na +-Ca 2+ exchanger to the Ca 2+-mediated vasodilation activated in endothelial cells of resistance arteries. FASEB J 2018; 32:2137-2147. [PMID: 29217667 DOI: 10.1096/fj.201700365rr] [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: 01/28/2023]
Abstract
Na+-Ca2+ exchanger (NCX) contributes to control the intracellular free Ca2+ concentration ([Ca2+]i), but the functional activation of NCX reverse mode (NCXrm) in endothelial cells is controversial. We evaluated the participation of NCXrm-mediated Ca2+ uptake in the endothelium-dependent vasodilation of rat isolated mesenteric arterial beds. In phenylephrine-contracted mesenteries, the acetylcholine (ACh)-induced vasodilation was abolished by treatment with the NCXrm blockers SEA0400, KB-R7943, or SN-6. Consistent with that, the ACh-induced hyperpolarization observed in primary cultures of mesenteric endothelial cells and in smooth muscle of isolated mesenteric resistance arteries was attenuated by KB-R7943 and SEA0400, respectively. In addition, both blockers abolished the NO production activated by ACh in intact mesenteric arteries. In contrast, the inhibition of NCXrm did not affect the vasodilator responses induced by the Ca2+ ionophore, ionomycin, and the NO donor, S-nitroso- N-acetylpenicillamine. Furthermore, SEA0400, KB-R7943, and a small interference RNA directed against NCX1 blunted the increase in [Ca2+]i induced by ACh or ATP in cultured endothelial cells. The analysis by proximity ligation assay showed that the NO-synthesizing enzyme, eNOS, and NCX1 were associated in endothelial cell caveolae of intact mesenteric resistance arteries. These results indicate that the activation of NCXrm has a central role in Ca2+-mediated vasodilation initiated by ACh in endothelial cells of resistance arteries.-Lillo, M. A., Gaete, P. S., Puebla, M., Ardiles, N. M., Poblete, I., Becerra, A., Simon, F., Figueroa, X. F. Critical contribution of Na+-Ca2+ exchanger to the Ca2+-mediated vasodilation activated in endothelial cells of resistance arteries.
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Affiliation(s)
- Mauricio A Lillo
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo S Gaete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariela Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás M Ardiles
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Inés Poblete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alvaro Becerra
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Facultad de Salud, Deporte y Recreación, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Felipe Simon
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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16
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Sherkhane P, Kapfhammer JP. Chronic pharmacological blockade of the Na + /Ca 2+ exchanger modulates the growth and development of the Purkinje cell dendritic arbor in mouse cerebellar slice cultures. Eur J Neurosci 2017; 46:2108-2120. [PMID: 28715135 DOI: 10.1111/ejn.13649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 01/22/2023]
Abstract
The Na+ /Ca2+ exchanger (NCX) is a bidirectional plasma membrane antiporter involved in Ca2+ homeostasis in eukaryotes. NCX has three isoforms, NCX1-3, and all of them are expressed in the cerebellum. Immunostaining on cerebellar slice cultures indicates that NCX is widely expressed in the cerebellum, including expression in Purkinje cells. The pharmacological blockade of the forward mode of NCX (Ca2+ efflux mode) by bepridil moderately inhibited growth and development of Purkinje cell dendritic arbor in cerebellar slice cultures. However, the blockade of the reverse mode (Ca2+ influx mode) by KB-R7943 severely reduced the dendritic arbor and induced a morphological change with thickened distal dendrites. The effect of KB-R7943 on dendritic growth was unrelated to the activity of voltage-gated calcium channels and was also apparent in the absence of bioelectrical activity indicating that it was mediated by NCX expressed in Purkinje cells. We have used additional NCX inhibitors including CB-DMB, ORM-10103, SEA0400, YM-244769, and SN-6 which have higher specificity for NCX isoforms and target either the forward, reverse, or both modes. These inhibitors caused a strong dendritic reduction similar to that seen with KB-R7943, but did not elicit thickening of distal dendrites. Our findings indicate that disturbance of the NCX-dependent calcium transport in Purkinje cells induces a reduction of dendritic arbor, which is presumably caused by changes in the calcium handling, and underline the importance of the calcium equilibrium for the dendritic development in cerebellar Purkinje cells.
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Affiliation(s)
- Pradeep Sherkhane
- Department of Biomedicine, Anatomical Institute, University of Basel, Pestalozzistrasse 20, CH-4056, Basel, Switzerland
| | - Josef P Kapfhammer
- Department of Biomedicine, Anatomical Institute, University of Basel, Pestalozzistrasse 20, CH-4056, Basel, Switzerland
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17
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Albano G, Dolder S, Siegrist M, Mercier-Zuber A, Auberson M, Stoudmann C, Hofstetter W, Bonny O, Fuster DG. Increased bone resorption by osteoclast-specific deletion of the sodium/calcium exchanger isoform 1 (NCX1). Pflugers Arch 2016; 469:225-233. [PMID: 27942992 DOI: 10.1007/s00424-016-1923-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/22/2016] [Accepted: 11/29/2016] [Indexed: 11/30/2022]
Abstract
Calcium is a key component of the bone mineral hydroxyapatite. During osteoclast-mediated bone resorption, hydroxyapatite is dissolved and significant quantities of calcium are released. Several calcium transport systems have previously been identified in osteoclasts, including members of the sodium/calcium exchanger (NCX) family. Expression pattern and physiological role of NCX isoforms in osteoclasts, however, remain largely unknown at the moment. Our data indicate that all three NCX isoforms (NCX1, NCX2, and NCX3) are present in murine osteoclasts. RANKL-induced differentiation of murine osteoclast precursors into mature osteoclasts significantly attenuated the expression of NCX1, while NCX2 and NCX3 expressions were largely unaffected. To study the role of NCX1 during osteoclast differentiation and bone resorption, we crossed mice with exon 11 of the NCX1 gene flanked by loxP sites with cathepsin K-Cre transgenic mice. Mature osteoclasts derived from transgenic mice exhibited an 80-90% reduction of NCX1 protein. In vitro studies indicate that NCX1 is dispensable for osteoclast differentiation, but NCX1-deficient osteoclasts exhibited increased resorptive activity. In line with these in vitro findings, mice with an osteoclast-targeted deletion of the NCX1 gene locus displayed an age-dependent loss of bone mass. Thus, in summary, our data reveal NCX1 as a regulator of osteoclast-mediated bone resorption.
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Affiliation(s)
- Giuseppe Albano
- Division of Nephrology, Hypertension and Clinical Pharmacology, Bern University Hospital, University of Bern, Freiburgstrasse 15, 3010, Bern, Switzerland
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- NCCR Transcure, University of Bern, Bern, Switzerland
- Department of Clinical Research, University of Bern, Bern, Switzerland
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland
| | - Silvia Dolder
- NCCR Transcure, University of Bern, Bern, Switzerland
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Mark Siegrist
- NCCR Transcure, University of Bern, Bern, Switzerland
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Annie Mercier-Zuber
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland
| | - Muriel Auberson
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland
| | - Candice Stoudmann
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland
| | - Willy Hofstetter
- NCCR Transcure, University of Bern, Bern, Switzerland
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Olivier Bonny
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland
| | - Daniel G Fuster
- Division of Nephrology, Hypertension and Clinical Pharmacology, Bern University Hospital, University of Bern, Freiburgstrasse 15, 3010, Bern, Switzerland.
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
- NCCR Transcure, University of Bern, Bern, Switzerland.
- Department of Clinical Research, University of Bern, Bern, Switzerland.
- NCCR Kidney.CH, University of Zürich, Zürich, Switzerland.
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18
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Yamashita K, Watanabe Y, Kita S, Iwamoto T, Kimura J. Inhibitory effect of YM-244769, a novel Na +/Ca 2+ exchanger inhibitor on Na +/Ca 2+ exchange current in guinea pig cardiac ventricular myocytes. Naunyn Schmiedebergs Arch Pharmacol 2016; 389:1205-1214. [PMID: 27480939 DOI: 10.1007/s00210-016-1282-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/21/2016] [Indexed: 11/28/2022]
Abstract
Recently, YM-244769 (N-(3-aminobenzyl)-6-{4-[(3-fluorobenzyl)oxy]phenoxy} nicotinamide) has been reported as a new potent and selective Na+/Ca2+ exchange (NCX) inhibitor by using various cells transfected with NCX using the 45Ca2+ fluorescent technique. However, the electrophysiological study of YM-244769 on NCX had not been performed in the mammalian heart. We examined the effects of YM-244769 on NCX current (INCX) in single cardiac ventricular myocytes of guinea pigs by using the whole-cell voltage clamp technique. YM-244769 suppressed the bidirectional INCX in a concentration-dependent manner. The IC50 values of YM-244769 for the bidirectional outward and inward INCX were both about 0.1 μM. YM-244769 suppressed the unidirectional outward INCX (Ca2+ entry mode) with an IC50 value of 0.05 μM. The effect on the unidirectional inward INCX (Ca2+ exit mode) was less potent, with 10 μM of YM-244769 resulting in the inhibition of only about 50 %. At 5 mM intracellular Na+ concentration, YM-244769 suppressed INCX more potently than it did at 0 mM [Na+]i. Intracellular application of trypsin via the pipette solution did not change the blocking effect of YM-244769. In conclusion, YM-244769 inhibits the Ca2+ entry mode of NCX more potently than the Ca2+ exit mode, and inhibition by YM-244769 is [Na+]i-dependent and trypsin-insensitive. These characteristics are similar to those of other benzyloxyphenyl derivative NCX inhibitors such as KB-R7943, SEA0400, and SN-6. The potency of YM-244769 as an NCX1 inhibitor is higher than those of KB-R7943 and SN-6 and is similar to that of SEA0400.
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Affiliation(s)
- Kanna Yamashita
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasuhide Watanabe
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| | - Satomi Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Junko Kimura
- Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima, Japan
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19
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Abstract
Na(+)/Ca(2+) exchangers (NCXs) have traditionally been viewed principally as a means of Ca(2+) removal from non-excitable cells. However there has recently been increasing interest in the operation of NCXs in reverse mode acting as a means of eliciting Ca(2+) entry into these cells. Reverse mode exchange requires a significant change in the normal resting transmembrane ion gradients and membrane potential, which has been suggested to occur principally via the coupling of NCXs to localised Na(+) entry through non-selective cation channels such as canonical transient receptor potential (TRPC) channels. Here we review evidence for functional or physical coupling of NCXs to non-selective cation channels, and how this affects NCX activity in non-excitable cells. In particular we focus on the potential role of nanojunctions, where the close apposition of plasma and intracellular membranes may help create the conditions needed for the generation of localised rises in Na(+) concentration that would be required to trigger reverse mode exchange.
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20
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Shenoda B. The role of Na+/Ca2+ exchanger subtypes in neuronal ischemic injury. Transl Stroke Res 2015; 6:181-90. [PMID: 25860439 DOI: 10.1007/s12975-015-0395-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 01/03/2023]
Abstract
The Na(+)/Ca(2+) exchanger (NCX) plays an important role in the maintenance of Na(+) and Ca(2+) homeostasis in most cells including neurons under physiological and pathological conditions. It exists in three subtypes (NCX1-3) with different tissue distributions but all of them are present in the brain. NCX transports Na(+) and Ca(2+) in either Ca(2+)-efflux (forward) or Ca(2+)-influx (reverse) mode, depending on membrane potential and transmembrane ion gradients. During neuronal ischemia, Na(+) and Ca(2+) ionic disturbances favor NCX to work in reverse mode, giving rise to increased intracellular Ca(2+) levels, while it may regain its forward mode activity on reperfusion. The exact significance of NCX in neuronal ischemic and reperfusion states remains unclear. The differential role of NCX subtypes in ischemic neuronal injury has been extensively investigated using various pharmacological tools as well as genetic models. This review discusses the mode of action of NCX in ischemic and reperfusion states, the differential roles played by NCX subtypes in these states as well as the role of NCX in pre- and postconditioning. NCX subtypes carry variable roles in ischemic injury. Furthermore, the mode of action of each subtype varies in ischemia and reperfusion states. Thus, therapeutic targeting of NCX in stroke should be based on appropriate timing of the administration of NCX subtype-specific strategies.
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Affiliation(s)
- Botros Shenoda
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th Street, Mail Stop #488, Philadelphia, PA, 19102, USA,
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21
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Gotoh Y, Kita S, Fujii M, Tagashira H, Horie I, Arai Y, Uchida S, Iwamoto T. Genetic knockout and pharmacologic inhibition of NCX2 cause natriuresis and hypercalciuria. Biochem Biophys Res Commun 2015; 456:670-5. [DOI: 10.1016/j.bbrc.2014.12.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
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22
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Iwamoto T, Kita S. [Verification of mutational analysis of NCX by eukaryotic CaCA crystal structure]. Nihon Yakurigaku Zasshi 2013; 142:318-319. [PMID: 24334932 DOI: 10.1254/fpj.142.318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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23
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Functional and structural properties of the NCKX2 Na(+)-Ca (2+)/K (+) exchanger: a comparison with the NCX1 Na (+)/Ca (2+) exchanger. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:81-94. [PMID: 23224872 DOI: 10.1007/978-1-4614-4756-6_8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Na(+)/Ca(2+)-K(+) exchangers (NCKX), alongside the more widely known Na(+)/Ca(2+) exchangers (NCX), are important players in the cellular Ca(2+) toolkit. But, unlike NCX, much less is known about the physiological roles of NCKX, while emergent evidence indicates that NCKX has highly specialized functions in cells and tissues where it is expressed. As their name implies, there are functional similarities in the properties of the two Ca(2+) exchanger families, but there are specific differences as well. Here, we compare and contrast their key functional properties of ionic dependence and affinities, as well as report on the effects of KB-R7943 - a compound that is widely used to differentiate the two exchangers. We also review structural similarities and differences between the two exchangers. The aim is to draw attention to key differences that will aid in differentiating the two exchangers in physiological contexts where both exist but perhaps play distinct roles.
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Zhang J. New insights into the contribution of arterial NCX to the regulation of myogenic tone and blood pressure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:329-43. [PMID: 23224892 DOI: 10.1007/978-1-4614-4756-6_28] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Plasma membrane protein Na(+)/Ca(2+) exchanger (NCX) in vascular smooth muscle (VSM) cells plays an important role in intracellular Ca(2+) homeostasis, Ca(2+) signaling, and arterial contractility. Recent evidence in intact animals reveals that VSM NCX type 1 (NCX1) is importantly involved in the control of arterial blood pressure (BP) in the normal state and in hypertension. Increased expression of vascular NCX1 has been implicated in human primary pulmonary hypertension and several salt-dependent hypertensive animal models. Our aim is to determine the molecular and physiological mechanisms by which vascular NCX influences vasoconstriction and BP normally and in salt-dependent hypertension. Here, we describe the relative contribution of VSM NCX1 to Ca(2+) signaling and arterial contraction, including recent data from transgenic mice (NCX1(smTg/Tg), overexpressors; NCX1(sm-/-), knockouts) that has begun to elucidate the specific contributions of NCX to BP regulation. Arterial contraction and BP correlate with the level of NCX1 expression in smooth muscle: NCX1(sm-/-) mice have decreased arterial myogenic tone (MT), vasoconstriction, and low BP. NCX1(smTg/Tg) mice have high BP and are more sensitive to salt; their arteries exhibit upregulated transient receptor potential canonical channel 6 (TRPC6) protein, increased MT, and vasoconstriction. These observations suggest that NCX is a key component of certain distinct signaling pathways that activate VSM contraction in response to stretch (i.e., myogenic response) and to activation of certain G-protein-coupled receptors. Arterial NCX expression and mechanisms that control the local (sub-plasma membrane) Na(+) gradient, including cation-selective receptor-operated channels containing TRPC6, regulate arterial Ca(2+) and constriction, and thus BP.
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Affiliation(s)
- Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Preferential involvement of Na⁺/Ca²⁺ exchanger type-1 in the brain damage caused by transient focal cerebral ischemia in mice. Biochem Biophys Res Commun 2012; 429:186-90. [PMID: 23137542 DOI: 10.1016/j.bbrc.2012.10.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 10/27/2012] [Indexed: 01/11/2023]
Abstract
The Na(+)/Ca(2+) exchanger (NCX), an ion-transporter located in the plasma membrane of neuronal cells, contributes to intracellular Ca(2+) homeostasis. Within the brain, three isoforms (NCX1, NCX2, and NCX3) are widely distributed. However, it is not clear to what extent these isoforms are involved in ischemic brain damage in mammals. We therefore used genetically altered mice and isoform-selective NCX inhibitors in a model of transient focal ischemia to investigate the role of each NCX isoform in ischemic brain damage. NCX isoform-mutant mice (NCX1(+/-), NCX2(+/-), and NCX3(+/-)) and wild-type mice were subjected to 90min of middle cerebral artery occlusion (MCAO) followed by 24h of reperfusion. One of three NCX inhibitors [SN-6, KB-R7943, or SEA0400 (3 or 10mgkg(-1), i.p.)] was administered to ddY mice at 30min before more prolonged (4-h) MCAO followed by 24h of reperfusion. After transient MCAO reperfusion, the cerebral infarcts in NCX1(+/-) mice, but not those in NCX2(+/-) or NCX3(+/-) mice, were significantly smaller than those in wild-type mice. SN-6 and SEA0400, which are more selective for the NCX1 isoform, significantly reduced the infarct volume at 10mg/kg. In contrast, KB-R7943, which is more selective for NCX3, did not. These results suggest that the NCX1 isoform may act preferentially (vs. the NCX2 and NCX3 isoforms) to exacerbate the cerebral damage caused by ischemic insult in mice, and that NCX1-selective inhibitors warrant investigation as a potential therapeutic agents for stroke.
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Chen Y, Payne K, Perara VS, Huang S, Baba A, Matsuda T, Yu X. Inhibition of the sodium-calcium exchanger via SEA0400 altered manganese-induced T1 changes in isolated perfused rat hearts. NMR IN BIOMEDICINE 2012; 25:1280-1285. [PMID: 22434695 PMCID: PMC3522749 DOI: 10.1002/nbm.2799] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 02/21/2012] [Accepted: 02/27/2012] [Indexed: 05/31/2023]
Abstract
Manganese (Mn(2+) )-enhanced MRI (MEMRI) provides the potential for the in vivo evaluation of calcium (Ca(2+) ) uptake in the heart. Recent studies have also suggested the role of the sodium-calcium (Na(+) -Ca(2+) ) exchanger (NCX) in Mn(2+) retention, which may have an impact on MEMRI signals. In this study, we investigated whether MEMRI with fast T(1) mapping allowed the sensitive detection of changes in NCX activity. We quantified the dynamics of the Mn(2+) -induced T(1) changes in isolated perfused rat hearts in response to SEA0400, an NCX inhibitor. The experimental protocol comprised 30 min of Mn(2+) perfusion (wash-in), followed by a 30-min wash-out period. There were three experimental groups: 1, NCX inhibition by 1 µ m SEA0400 during Mn(2+) wash-in only (SEAin, n=6); 2, NCX inhibition by 1 µ m SEA0400 during Mn(2+) wash-out only (SEAout, n=6); 3, no NCX inhibition during both wash-in and wash-out to serve as the control group (CNTL, n=5). Rapid T(1) mapping at a temporal resolution of 3 min was performed throughout the perfusion protocol using a triggered saturation-recovery Look-Locker sequence. Our results showed that NCX inhibition during Mn(2+) wash-in caused a significant increase in relaxation rate (R(1) ) at the end of Mn(2+) perfusion. During the wash-out period, NCX inhibition led to less reduction in R(1) . Further analysis of Mn(2+) content in myocardium with flame atomic absorption spectroscopy was consistent with the MRI findings. These results suggest that Mn(2+) accumulation and retention in rat hearts are, in part, dependent on NCX activity. Hence, MEMRI may provide an imaging method that is also sensitive to changes in NCX activity.
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Affiliation(s)
- Ya Chen
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA
| | - Kevin Payne
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | | | - Songping Huang
- Department of Chemistry, Kent State University, Kent, OH, USA
| | - Akemichi Baba
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Toshio Matsuda
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
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Molinaro P, Cantile M, Cuomo O, Secondo A, Pannaccione A, Ambrosino P, Pignataro G, Fiorino F, Severino B, Gatta E, Sisalli MJ, Milanese M, Scorziello A, Bonanno G, Robello M, Santagada V, Caliendo G, Di Renzo G, Annunziato L. Neurounina-1, a novel compound that increases Na+/Ca2+ exchanger activity, effectively protects against stroke damage. Mol Pharmacol 2012; 83:142-56. [PMID: 23066092 DOI: 10.1124/mol.112.080986] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have demonstrated that the knockdown or knockout of the three Na(+)/Ca(2+) exchanger (NCX) isoforms, NCX1, NCX2, and NCX3, worsens ischemic brain damage. This suggests that the activation of these antiporters exerts a neuroprotective action against stroke damage. However, drugs able to increase the activity of NCXs are not yet available. We have here succeeded in synthesizing a new compound, named neurounina-1 (7-nitro-5-phenyl-1-(pyrrolidin-1-ylmethyl)-1H-benzo[e][1,4]diazepin-2(3H)-one), provided with an high lipophilicity index and able to increase NCX activity. Ca(2+) radiotracer, Fura-2 microfluorimetry, and patch-clamp techniques revealed that neurounina-1 stimulated NCX1 and NCX2 activities with an EC(50) in the picomolar to low nanomolar range, whereas it did not affect NCX3 activity. Furthermore, by using chimera strategy and site-directed mutagenesis, three specific molecular determinants of NCX1 responsible for neurounina-1 activity were identified in the α-repeats. Interestingly, NCX3 became responsive to neurounina-1 when both α-repeats were replaced with the corresponding regions of NCX1. In vitro studies showed that 10 nM neurounina-1 reduced cell death of primary cortical neurons exposed to oxygen-glucose deprivation followed by reoxygenation. Moreover, in vitro, neurounina-1 also reduced γ-aminobutyric acid (GABA) release, enhanced GABA(A) currents, and inhibited both glutamate release and N-methyl-d-aspartate receptors. More important, neurounina-1 proved to have a wide therapeutic window in vivo. Indeed, when administered at doses of 0.003 to 30 μg/kg i.p., it was able to reduce the infarct volume of mice subjected to transient middle cerebral artery occlusion even up to 3 to 5 hours after stroke onset. Collectively, the present study shows that neurounina-1 exerts a remarkable neuroprotective effect during stroke and increases NCX1 and NCX2 activities.
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Affiliation(s)
- Pasquale Molinaro
- Division of Pharmacology, Department of Neuroscience, School of Medicine, "Federico II" University of Naples, Via Pansini 5, 80131 Naples, Italy
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Abstract
The binding of Ca(2+) to two adjacent Ca(2+)-binding domains, CBD1 and CBD2, regulates ion transport in the Na(+)/Ca(2+) exchanger. As sensors for intracellular Ca(2+), the CBDs form electrostatic switches that induce the conformational changes required to initiate and sustain Na(+)/Ca(2+) exchange. Depending on the presence of a few key residues in the Ca(2+)-binding sites, zero to four Ca(2+) ions can bind with affinities between 0.1 to 20 μm. Importantly, variability in CBD2 as a consequence of alternative splicing modulates not only the number and affinities of the Ca(2+)-binding sites in CBD2 but also the Ca(2+) affinities in CBD1.
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Affiliation(s)
- Mark Hilge
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University Basel, CH-4058 Basel, Switzerland.
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de la Cruz GG, Groschner K, Oliver Kappe C, Glasnov TN. High-speed microwave assisted synthesis of SEA0400—a selective inhibitor of the Na+/Ca2+ exchanger. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.04.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rahman M, Inman M, Kiss L, Janssen LJ. Reverse-mode NCX current in mouse airway smooth muscle: Na(+) and voltage dependence, contributions to Ca(2+) influx and contraction, and altered expression in a model of allergen-induced hyperresponsiveness. Acta Physiol (Oxf) 2012; 205:279-91. [PMID: 22212361 DOI: 10.1111/j.1748-1716.2011.02401.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 11/21/2011] [Accepted: 12/15/2011] [Indexed: 01/31/2023]
Abstract
AIM We examined the electrophysiological properties of reverse-mode Na(+) /Ca(2+) exchange (NCX) in mouse airway smooth muscle (ASM), assessing its contributions to regulation of [Ca(2+) ], and its expression in acute and chronic airway hyperresponsiveness (AHR). METHODS Membrane currents were studied in single murine ASM cells under voltage clamp at -60 mV using ramp depolarizing commands to +80 mV. Confocal fluorimetric and RT-PCR techniques were used to monitor changes in cytosolic [Ca(2+) ] and NCX expression, respectively. RESULTS With standard KCl-containing electrode, 30 μm KB-R7943 (an inhibitor of reverse-mode NCX activity) exhibited variable effects on membrane current, indicating modulation of more than one conductance. KB-R7943 activated outwardly rectifying current that was inhibited by 100 μm iberiotoxin (blocker of large-conductance Ca(2+) -dependent K(+) channels), indicating a direct enhancing effect of KB-R7943 on those K(+) channels. After obviating K(+) currents, we found that a current sensitive to 4-4'-diisothiocyanostilbene-2,2'-disulfonic acid (blocker of Ca(2+) -dependent Cl- channels) was markedly increased by elevating [Na(+) ] in the electrode solution to 13, 15.5 and 18 mm and suppressed by KB-R7943, indicating Ca(2+) influx via reverse-mode NCX activity. With conditions preventing Ca(2+) influx through voltage-dependent Ca(2+) channels but promoting that through NCX, we found that introduction of Ca(2+) led to marked but transient KB-R7943-sensitive elevation of [Ca(2+) ]. Additionally, KB-R7943 suppressed cholinergically evoked Ca(2+) waves. Finally, NCX1 expression was not significantly changed in allergen-induced AHR acute model but increased approx. 2.5-fold in a chronic model. CONCLUSION Reverse-mode NCX activity leads to a physiologically relevant increase in [Ca(2+) ] even under control conditions, and this may be exaggerated in allergen-induced AHR and asthma.
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Affiliation(s)
- M. Rahman
- Firestone Institute for Respiratory Health; St. Joseph's Hospital; Department of Medicine; McMaster University; Hamilton; ON; Canada
| | - M. Inman
- Firestone Institute for Respiratory Health; St. Joseph's Hospital; Department of Medicine; McMaster University; Hamilton; ON; Canada
| | - L. Kiss
- Institute of Pharmaceutical Chemistry; University of Szeged; Szeged; Hungary
| | - L. J. Janssen
- Firestone Institute for Respiratory Health; St. Joseph's Hospital; Department of Medicine; McMaster University; Hamilton; ON; Canada
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Systemic hypertension: the roles of salt, vascular Na+/K+ ATPase and the endogenous glycosides, ouabain and marinobufagenin. Cardiol Rev 2012; 20:130-8. [PMID: 22183064 DOI: 10.1097/crd.0b013e31823c835c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Essential hypertension has been shown to be significantly associated with an increased risk for cardiovascular disease and is not well controlled in many patients. In a large portion of people with essential hypertension, sodium intake has been shown to play a significant role in the production of their hypertension. The mechanism through which increased sodium intake manifests hypertension is unresolved and likely multifactorial. Endogenous cardiac glycosides such as endogenous ouabain (EO) and marinobufagenin have been proposed to play a role in salt-sensitive essential hypertension through their inhibition of Na/K ATPase (NKA). The normal function of the NKA pump is to extrude Na from the intracellular environment and import K. Blocking the NKA disrupts its normal maintenance function. EO is proposed to produce alteration in smooth muscle cell contractility by inhibiting the α2-isoform of NKA, altering Na in a microdomain of the cell. In this region of the plasma membrane the α2-isoform of the NKA colocalizes with another transmembrane protein, the Na/Ca exchanger (NCX). The normal function of NCX is to extrude Ca and import Na. Inhibition of NKA produces an increase in Na within the microdomain, which in turn alters the function of the NCX so that less Ca is extruded, leading to increased intracellular Ca and increased vascular contraction. EO has been shown to be synthesized and secreted by the adrenal cortex in response to chronically elevated sodium intake. The levels of EO have been shown to be significantly elevated in 40% of all untreated hypertensive patients. Marinobufagenin, another cardiac glycoside, has also been implicated as a possible cause of essential hypertension through its preferential inhibition of the α1-isoform of NKA. Antagonism of the endogenous inhibitors of NKA is currently a target of clinical research for the development of innovative antihypertensive treatments.
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Jacobs BE, Liu Y, Pulina MV, Golovina VA, Hamlyn JM. Normal pregnancy: mechanisms underlying the paradox of a ouabain-resistant state with elevated endogenous ouabain, suppressed arterial sodium calcium exchange, and low blood pressure. Am J Physiol Heart Circ Physiol 2012; 302:H1317-29. [PMID: 22245773 DOI: 10.1152/ajpheart.00532.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endogenous cardiotonic steroids (CTS) raise blood pressure (BP) via vascular sodium calcium exchange (NCX1.3) and transient receptor-operated channels (TRPCs). Circulating CTS are superelevated in pregnancy-induced hypertension and preeclampsia. However, their significance in normal pregnancy, where BP is low, is paradoxical. Here we test the hypothesis that vascular resistance to endogenous ouabain (EO) develops in normal pregnancy and is mediated by reduced expression of NCX1.3 and TRPCs. We determined plasma and adrenal levels of EO and the impact of exogenous ouabain in pregnancy on arterial expression of Na(+) pumps, NCX1.3, TRPC3, and TRPC6 and BP. Pregnant (embryonic day 4) and nonpregnant rats received infusions of ouabain or vehicle. At 14-16 days, tissues and plasma were collected for blotting and EO assay by radioimmunoassay (RIA), liquid chromatography (LC)-RIA, and LC-multidimensional mass spectrometry (MS3). BP (-8 mmHg; P < 0.05) and NCX1.3 expression fell (aorta -60% and mesenteric artery -30%; P < 0.001) in pregnancy while TRPC expression was unchanged. Circulating EO increased (1.14 ± 0.13 nM) vs. nonpregnant (0.6 ± 0.08 nM; P < 0.05) and was confirmed by LC-MS3 and LC-RIA. LC-MS3 revealed two previously unknown isomers of EO; one increased ∼90-fold in pregnancy. Adrenal EO but not isomers were increased in pregnancy. In nonpregnant rats, similar infusions of ouabain raised BP (+24 ± 3 mmHg; P < 0.001). In ouabain-infused rats, impaired fetal and placental growth occurred with no BP increase. In summary, normal pregnancy is an ouabain-resistant state associated with low BP, elevated circulating levels of EO, two novel steroidal EO isomers, and increased adrenal mass and EO content. Ouabain raises BP only in nonpregnant animals. Vascular resistance to the chronic pressor activity of endogenous and exogenous ouabain is mediated by suppressed NCX1.3 and reduced sensitivity of events downstream of Ca(2+) entry. The mechanisms of EO resistance and the impaired fetal and placental growth due to elevated ouabain may be important in pregnancy-induced hypertension (PIH) and preeclampsia (PE).
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Affiliation(s)
- Brandiese E Jacobs
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, USA
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Alternative strategies in arrhythmia therapy: evaluation of Na/Ca exchange as an anti-arrhythmic target. Pharmacol Ther 2011; 134:26-42. [PMID: 22197992 DOI: 10.1016/j.pharmthera.2011.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 11/22/2011] [Accepted: 11/22/2011] [Indexed: 01/08/2023]
Abstract
The search for alternative anti-arrhythmic strategies is fueled by an unmet medical need as well as by the opportunities arising from identification of novel targets and novel drugs. Na/Ca exchange is a potential target involved in several types of arrhythmias, such as those related to ischemia-reperfusion, heart failure and also some forms of genetic arrhythmias. Inhibition of Na/Ca exchange is theoretically not only anti-arrhythmic but also increases cellular Ca(2+) content. This could be an advantage in conditions of low inotropy, such as in heart failure, but may also worsen conditions such as the recovery from ischemia or relaxation abnormalities. With the available drugs such as KB-R7943 and SEA-0400 these theories have now been tested in a number of cellular and in vivo models. Experience is overall rather positive and seems less hampered by the potential drawbacks than expected. This may be because the currently available drugs are not highly selective, with additional benefit derived from concurrent effects. While this precludes a definite answer regarding the benefit of a pure NCX inhibitor, they indicate that Na/Ca exchange inhibition as part of a multi-target strategy is an avenue to be considered. Such studies will need further 'bench' work and testing in relevant preclinical models, including chronic disease.
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Ago Y, Kawasaki T, Nashida T, Ota Y, Cong Y, Kitamoto M, Takahashi T, Takuma K, Matsuda T. SEA0400, a specific Na+/Ca2+ exchange inhibitor, prevents dopaminergic neurotoxicity in an MPTP mouse model of Parkinson's disease. Neuropharmacology 2011; 61:1441-51. [PMID: 21903118 DOI: 10.1016/j.neuropharm.2011.08.041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 08/24/2011] [Accepted: 08/26/2011] [Indexed: 12/14/2022]
Abstract
We have recently shown that the Na(+)/Ca(2+) exchanger (NCX) is involved in nitric oxide (NO)-induced cytotoxicity in cultured astrocytes and neurons. However, there is no in vivo evidence suggesting the role of NCX in neurodegenerative disorders associated with NO. NO is implicated in the pathogenesis of neurodegenerative disorders such as Parkinson's disease. This study examined the effect of SEA0400, the specific NCX inhibitor, on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity, a model of Parkinson's disease, in C57BL/6J mice. MPTP treatment (10 mg/kg, four times at 2-h intervals) decreased dopamine levels in the midbrain and impaired motor coordination, and these effects were counteracted by S-methylthiocitrulline, a selective neuronal NO synthase inhibitor. SEA0400 protected against the dopaminergic neurotoxicity (determined by dopamine levels in the midbrain and striatum, tyrosine hydroxylase immunoreactivity in the substantia nigra and striatum, striatal dopamine release, and motor deficits) in MPTP-treated mice. SEA0400 had no radical-scavenging activity. SEA0400 did not affect MPTP metabolism and MPTP-induced NO production and microglial activation, while it attenuated MPTP-induced increases in extracellular signal-regulated kinase (ERK) phosphorylation and lipid peroxidation product, thiobarbituric acid reactive substance. These findings suggest that SEA0400 protects against MPTP-induced neurotoxicity probably by blocking ERK phosphorylation and lipid peroxidation which are downstream of NCX-mediated Ca(2+) influx.
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Affiliation(s)
- Yukio Ago
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
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Kaur H, Jaggi AS, Singh N. Modulation of neuroprotective effect of ischemic post-conditioning by dichlorobenzamil a Na(+)/Ca(2+) exchanger inhibitor in mice. Biol Pharm Bull 2010; 33:585-91. [PMID: 20410590 DOI: 10.1248/bpb.33.585] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study has been designed to investigate the modulatory role of dichlorobenzamil a Na(+)/Ca(2+) exchanger inhibitor in ischemic post-conditioning-induced neuroprotection in mice. Bilateral carotid artery occlusion followed by reperfusion, produced a significant rise in cerebral infarct size along with impairment of memory and motor coordination. Ischemic post-conditioning involving three episodes of 10 s carotid artery occlusion with intermittent reperfusion of 10 s proceeding prolonged ischemic insult of 12 min, produced a significant decrease in cerebral infarct size along with reversal of ischemia-reperfusion-induced impairment of memory and motor coordination. Ischemic post-conditioning-induced neuroprotective effects were significantly abolished by pretreatment with dichlorobenzamil (DBZ 0.5, 1 mg/kg, intraperitoneal) a Na(+)/Ca(2+) exchange inhibitor. It may be concluded that Na(+)/Ca(2+) exchanger possibly plays an important role in ischemic post-conditioning-induced neuroprotection.
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Affiliation(s)
- Hardeep Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, India
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Kintner DB, Chen X, Currie J, Chanana V, Ferrazzano P, Baba A, Matsuda T, Cohen M, Orlowski J, Chiu SY, Taunton J, Sun D. Excessive Na+/H+ exchange in disruption of dendritic Na+ and Ca2+ homeostasis and mitochondrial dysfunction following in vitro ischemia. J Biol Chem 2010; 285:35155-68. [PMID: 20817726 DOI: 10.1074/jbc.m110.101212] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal dendrites are vulnerable to injury under diverse pathological conditions. However, the underlying mechanisms for dendritic Na(+) overload and the selective dendritic injury remain poorly understood. Our current study demonstrates that activation of NHE-1 (Na(+)/H(+) exchanger isoform 1) in dendrites presents a major pathway for Na(+) overload. Neuronal dendrites exhibited higher pH(i) regulation rates than soma as a result of a larger surface area/volume ratio. Following a 2-h oxygen glucose deprivation and a 1-h reoxygenation, NHE-1 activity was increased by ∼70-200% in dendrites. This elevation depended on activation of p90 ribosomal S6 kinase. Moreover, stimulation of NHE-1 caused dendritic Na(+)(i) accumulation, swelling, and a concurrent loss of Ca(2+)(i) homeostasis. The Ca(2+)(i) overload in dendrites preceded the changes in soma. Inhibition of NHE-1 or the reverse mode of Na(+)/Ca(2+) exchange prevented these changes. Mitochondrial membrane potential in dendrites depolarized 40 min earlier than soma following oxygen glucose deprivation/reoxygenation. Blocking NHE-1 activity not only attenuated loss of dendritic mitochondrial membrane potential and mitochondrial Ca(2+) homeostasis but also preserved dendritic membrane integrity. Taken together, our study demonstrates that NHE-1-mediated Na(+) entry and subsequent Na(+)/Ca(2+) exchange activation contribute to the selective dendritic vulnerability to in vitro ischemia.
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Affiliation(s)
- Douglas B Kintner
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, USA
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Condrescu M, Reeves JP. Inhibition of sodium–calcium exchange by KB-R7943: Dodecylamine and sphingosine in transfected Chinese hamster ovary cells. Cell Calcium 2010; 47:404-11. [DOI: 10.1016/j.ceca.2010.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/05/2010] [Accepted: 02/08/2010] [Indexed: 12/13/2022]
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Algara-Suárez P, Mejía-Elizondo R, Sims SM, Saavedra-Alanis VM, Espinosa-Tanguma R. The 1.3 isoform of Na+-Ca 2+ exchanger expressed in guinea pig tracheal smooth muscle is less sensitive to KB-R7943. J Physiol Biochem 2010; 66:117-25. [PMID: 20428991 DOI: 10.1007/s13105-010-0016-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 04/13/2010] [Indexed: 10/19/2022]
Abstract
The sodium-calcium exchanger (NCX) plays a major role in the regulation of cytosolic Ca(2+) in muscle cells. In this work, we performed force experiments to explore the role of NCX during contraction and relaxation of Cch-stimulated guinea pig tracheal smooth muscle strips. This tissue showed low sensitivity to NCX inhibitor KB-R7943 (IC50, 57 +/- 2 microM), although a complete relaxation was obtained by NCX inhibition at 100 microM. Interestingly, relaxation after washing the agonist was prolonged in the absence of external Na(+), whereas washing without Na(+) and in the presence of KB-R7943 resembled control conditions with physiological solution. Altogether, this suggests the reversal of NCX to a Ca(2+) influx mode by the manipulation on the Na(+) gradient, which can be inhibited by KB-R7943. In order to understand the low sensitivity to KB-R7943, we studied the molecular aspects of the NCX expressed in this tissue and found that the isoform of NCX expressed is 1.3, similar to that described in human tracheal smooth muscle. Sequencing revealed that amino acid 19 in exon B is phenylalanine, whereas in its human counterpart is leucine, and that the first amino acid after exon D is aspartate instead of glutamate in humans. Results herein presented are discussed in term of their possible functional implications in the exchanger activity and thus in airway physiology.
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Affiliation(s)
- Paola Algara-Suárez
- Department of Physiology, Facultad de Medicina de la Universidad Autónoma de San Luis Potosí, Av. V. Carranza 2405, San Luis Potosí, San Luis Potosí 78210, Mexico
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Tsumura M, Okumura R, Tatsuyama S, Ichikawa H, Muramatsu T, Matsuda T, Baba A, Suzuki K, Kajiya H, Sahara Y, Tokuda M, Momose Y, Tazaki M, Shimono M, Shibukawa Y. Ca2+ Extrusion via Na+-Ca2+ Exchangers in Rat Odontoblasts. J Endod 2010; 36:668-74. [DOI: 10.1016/j.joen.2010.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 01/06/2010] [Accepted: 01/15/2010] [Indexed: 11/16/2022]
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Signaling mechanisms that link salt retention to hypertension: endogenous ouabain, the Na(+) pump, the Na(+)/Ca(2+) exchanger and TRPC proteins. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1219-29. [PMID: 20211726 DOI: 10.1016/j.bbadis.2010.02.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 02/26/2010] [Accepted: 02/27/2010] [Indexed: 12/26/2022]
Abstract
Salt retention as a result of chronic, excessive dietary salt intake, is widely accepted as one of the most common causes of hypertension. In a small minority of cases, enhanced Na(+) reabsorption by the kidney can be traced to specific genetic defects of salt transport, or pathological conditions of the kidney, adrenal cortex, or pituitary. Far more frequently, however, salt retention may be the result of minor renal injury or small genetic variation in renal salt transport mechanisms. How salt retention actually leads to the increase in peripheral vascular resistance (the hallmark of hypertension) and the elevation of blood pressure remains an enigma. Here we review the evidence that endogenous ouabain (an adrenocortical hormone), arterial smooth muscle α2 Na(+) pumps, type-1 Na/Ca exchangers, and receptor- and store-operated Ca(2+) channels play key roles in the pathway that links salt to hypertension. We discuss cardenolide structure-function relationships in an effort to understand why prolonged administration of ouabain, but not digoxin, induces hypertension, and why digoxin is actually anti-hypertensive. Finally, we summarize recent observations which indicate that ouabain upregulates arterial myocyte Ca(2+) signaling mechanisms that promote vasoconstriction, while simultaneously downregulating endothelial vasodilator mechanisms. In sum, the reports reviewed here provide novel insight into the molecular mechanisms by which salt retention leads to hypertension.
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Okumura R, Shibukawa Y, Muramatsu T, Hashimoto S, Nakagawa KI, Tazaki M, Shimono M. Sodium-calcium exchangers in rat ameloblasts. J Pharmacol Sci 2010; 112:223-30. [PMID: 20118617 DOI: 10.1254/jphs.09267fp] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Although the central role of ameloblasts in synthesis and resorption of enamel matrix proteins during amelogenesis is well documented, the Ca(2+)-transport/extrusion mechanism remains to be fully elucidated. To clarify Ca(2+)-transport in rat ameloblasts, we investigated expression and localization of Na(+)-Ca(2+) exchanger (NCX) isoforms and the functional characteristics of their ion transporting/pharmacological properties. RT-PCR and immunohistochemical analyses revealed expression of NCX1 and NCX3 in ameloblasts, localized in the apical membrane. In patch-clamp recordings, Ca(2+) efflux by Na(+)-Ca(2+) exchange showed dependence on external Na(+). Ca(2+) influx by Na(+)-Ca(2+) exchange, measured by fura-2 fluorescence, showed dependence on extracellular Ca(2+) concentration, and it was blocked by NCX inhibitors KB-R7943, SEA0400, and SN-6. These results showed significant expression of NCX1 and NCX3 in ameloblasts, indicating their involvement in the directional Ca(2+) extrusion pathway from cells to the enamel mineralizing front.
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Affiliation(s)
- Reijiro Okumura
- Oral Health Science Center, hrc7, Tokyo Dental College, Mihama-ku, Chiba 261-8502, Japan
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Kepp K, Org E, Sõber S, Kelgo P, Viigimaa M, Veldre G, Tõnisson N, Juhanson P, Putku M, Kindmark A, Kozich V, Laan M. Hypervariable intronic region in NCX1 is enriched in short insertion-deletion polymorphisms and showed association with cardiovascular traits. BMC MEDICAL GENETICS 2010; 11:15. [PMID: 20109173 PMCID: PMC2832636 DOI: 10.1186/1471-2350-11-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 01/28/2010] [Indexed: 01/07/2023]
Abstract
Background Conserved non-coding regions (CNR) have been shown to harbor gene expression regulatory elements. Genetic variations in these regions may potentially contribute to complex disease susceptibility. Methods We targeted CNRs of cardiovascular disease (CVD) candidate gene, Na(+)-Ca(2+) exchanger (NCX1) with polymorphism screening among CVD patients (n = 46) using DHPLC technology. The flanking region (348 bp) of the 14 bp indel in intron 2 was further genotyped by DGGE assay in two Eastern-European CVD samples: essential hypertension (HYPEST; 470 cases, 652 controls) and coronary artery disease, CAD (CADCZ; 257 cases, controls 413). Genotype-phenotype associations were tested by regression analysis implemented in PLINK. Alignments of primate sequences were performed by ClustalW2. Results Nine of the identified NCX1 variants were either singletons or targeted by commercial platforms. The 14 bp intronic indel (rs11274804) was represented with substantial frequency in HYPEST (6.82%) and CADCZ (14.58%). Genotyping in Eastern-Europeans (n = 1792) revealed hypervariable nature of this locus, represented by seven alternative alleles. The alignments of human-chimpanzee-macaque sequences showed that the major human variant (allele frequency 90.45%) was actually a human-specific deletion compared to other primates. In humans, this deletion was surrounded by other short (5-43 bp) deletion variants and a duplication (40 bp) polymorphism possessing overlapping breakpoints. This indicates a potential indel hotspot, triggered by the initial deletion in human lineage. An association was detected between the carrier status of 14 bp indel ancestral allele and CAD (P = 0.0016, OR = 2.02; Bonferroni significance level alpha = 0.0045), but not with hypertension. The risk for the CAD development was even higher among the patients additionally diagnosed with metabolic syndrome (P = 0.0014, OR = 2.34). Consistent with the effect on metabolic processes, suggestive evidence for the association with heart rate, serum triglyceride and LDL levels was detected (P = 0.04). Conclusions Compared to SNPs targeted by large number of locus-specific and genome-wide assays, considerably less attention has been paid to short indel variants in the human genome. The data of genome dynamics, mutation rate and population genetics of short indels, as well as their impact on gene expressional profile and human disease susceptibility is limited. The characterization of NCX1 intronic hypervariable non-coding region enriched in human-specific indel variants contributes to this gap of knowledge.
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Affiliation(s)
- Katrin Kepp
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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Jaitovich A, Bertorello AM. Salt, Na+,K+-ATPase and hypertension. Life Sci 2009; 86:73-8. [PMID: 19909757 DOI: 10.1016/j.lfs.2009.10.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/27/2009] [Accepted: 10/30/2009] [Indexed: 12/20/2022]
Abstract
Chronic hypertension is characterized by a persistent increase in vascular tone. Sodium-rich diets promote hypertension; however, the underlying molecular mechanisms are not fully understood. Variations in the sodium content of the diet, through hormonal mediators such as dopamine and angiotensin II, modulate renal tubule Na(+),K(+)-ATPase activity. Stimulation of Na(+),K(+)-ATPase activity increases sodium transport across the renal proximal tubule epithelia, promoting Na(+) retention, whereas inhibited Na(+),K(+)-ATPase activity decreases sodium transport, and thereby natriuresis. Diets rich in sodium also enhance the release of adrenal endogenous ouabain-like compounds (OLC), which inhibit Na(+),K(+)-ATPase activity, resulting in increased intracellular Na(+) and Ca(2+) concentrations in vascular smooth muscle cells, thus increasing the vascular tone, with a corresponding increase in blood pressure. The mechanisms by which these homeostatic processes are integrated in response to salt intake are complex and not completely elucidated. However, recent scientific findings provide new insights that may offer additional avenues to further explore molecular mechanisms related to normal physiology and pathophysiology of various forms of hypertension (i.e. salt-induced). Consequently, new strategies for the development of improved therapeutics and medical management of hypertension are anticipated.
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Affiliation(s)
- Ariel Jaitovich
- Membrane Signaling Networks, Atherosclerosis Research Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Solna, 171 76 Stockholm, Sweden.
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Soliman D, Hamming KS, Matemisz LC, Light PE. Reactive oxygen species directly modify sodium–calcium exchanger activity in a splice variant-dependent manner. J Mol Cell Cardiol 2009; 47:595-602. [DOI: 10.1016/j.yjmcc.2009.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 05/15/2009] [Accepted: 05/16/2009] [Indexed: 11/15/2022]
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Sakamoto K, Owada Y, Shikama Y, Wada I, Waguri S, Iwamoto T, Kimura J. Involvement of Na+/Ca2+ exchanger in migration and contraction of rat cultured tendon fibroblasts. J Physiol 2009; 587:5345-59. [PMID: 19770194 DOI: 10.1113/jphysiol.2009.172080] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In response to injury and inflammation of tendons, tendon fibroblasts are activated, migrate to the wound, and eventually induce contraction of the extracellular matrices to repair the tissue. Under such conditions, Ca(2+) signalling is involved in motility and contractility of tendon fibroblasts. Using cultured tendon fibroblasts isolated from rat Achilles tendons, we investigated functional expression of Na(+)/Ca(2+) exchangers (NCX). The fluorometric study showed that the intracellular Ca(2+) concentration ([Ca(2+)](i)) was increased by reducing extracellular Na(+) concentration ([Na(+)](o)) in tendon fibroblasts. Selective NCX inhibitors, KB-R7943 and SEA0400, both attenuated [Na(+)](o)-dependent [Ca(2+)](i) elevation and the resting [Ca(2+)](i) in tendon fibroblasts. RT-PCR, Western blots and sequence analyses revealed that NCX1.3 and NCX1.7 were expressed in cultured tendon fibroblasts. NCX2 mRNA was undetected. NCX3 expression was negligibly low. Immunofluorescence microscopy indicated that NCX1 protein localized in the plasma membrane especially at the microspikes of tendon fibroblasts. In the wound-healing scratch assay, the cells migrated toward the space created by a scratch and almost completely filled the space within 48 h. This phenomenon was significantly suppressed by KB-R7943 and SEA0400. Furthermore, the NCX inhibitors abrogated the tendon fibroblast-mediated collagen-matrix contractions. Two types of siRNAs for NCX1 also suppressed the migration and contraction of tendon fibroblasts. We conclude that NCX is expressed and mediates Ca(2+) influx in cultured tendon fibroblasts. Since the pharmacological inhibitors and siRNA for NCX1 suppressed motility and contractility of tendon fibroblasts, NCX may play an important role in the function of tendon fibroblasts in the wound healing.
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Affiliation(s)
- Kazuho Sakamoto
- Department of Pharmacology, Fukushima Medical University, School of Medicine, Hikarigaoka, Fukushima, Japan.
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Inokuchi Y, Shimazawa M, Nakajima Y, Komuro I, Matsuda T, Baba A, Araie M, Kita S, Iwamoto T, Hara H. A Na+/Ca2+ exchanger isoform, NCX1, is involved in retinal cell death after N-methyl-D-aspartate injection and ischemia-reperfusion. J Neurosci Res 2009; 87:906-17. [PMID: 18855935 DOI: 10.1002/jnr.21906] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We investigated the expression of Na(+)/Ca(2+) exchanger (NCX) and the functional role of NCX in retinal damage by using NCX1-heterozygous deficient mice (NCX1(+/-)) and SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy] phenoxy]-5-ethoxyaniline), a selective NCX inhibitor in vivo. We also examined the role of NCX in oxygen-glucose deprivation (OGD) stress with a retinal ganglion cell line (RGC-5) cell culture in vitro. The expression of NCX1 was confirmed and entirely localized in retina by immunoblotting and immunohistochemistry, respectively. NCX1(+/-) mice possessed significant protection against retinal damage induced by intravitreal injection of N-methyl-D-aspartate (NMDA). SEA0400 at 3 and 10 mg/kg significantly reduced NMDA- or high intraocular pressure-induced retinal cell damage in mice. Furthermore, SEA0400 reduced the number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling)-positive cells and the expression of phosphorylated mitogen-activated protein kinases (ERK1/2, JNK, p38) induced by NMDA injection. In RGC-5, SEA0400 at 0.3 and 1 microM significantly inhibited OGD-induced cell damage. OGD-induced cell damage was aggravated by ouabain (a Na(+),K(+)-ATPase inhibitor) at 100 microM, and this increased damage was significantly reduced by SEA0400 at 1 microM. In conclusion, these results suggest that NCX1 may play a role in retinal cell death induced by NMDA and ischemia-reperfusion.
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Affiliation(s)
- Y Inokuchi
- Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
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Kashihara T, Nakayama K, Matsuda T, Baba A, Ishikawa T. Role of Na+/Ca2+ Exchanger–Mediated Ca2+ Entry in Pressure-Induced Myogenic Constriction in Rat Posterior Cerebral Arteries. J Pharmacol Sci 2009; 110:218-22. [DOI: 10.1254/jphs.09054sc] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Blaustein MP, Zhang J, Chen L, Song H, Raina H, Kinsey SP, Izuka M, Iwamoto T, Kotlikoff MI, Lingrel JB, Philipson KD, Wier WG, Hamlyn JM. The pump, the exchanger, and endogenous ouabain: signaling mechanisms that link salt retention to hypertension. Hypertension 2008; 53:291-8. [PMID: 19104005 DOI: 10.1161/hypertensionaha.108.119974] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, 655 W Baltimore St, Baltimore, MD 21201, USA.
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Mayer G. An update on the relationship between the kidney, salt and hypertension. Wien Med Wochenschr 2008; 158:365-9. [PMID: 18677586 DOI: 10.1007/s10354-008-0559-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 02/04/2008] [Indexed: 12/24/2022]
Abstract
The relationship between salt intake and blood pressure has been noteworthy for a long time. Nevertheless, the complex hemodynamic alterations associated with the salt-induced blood pressure changes have become clear only quite recently. Despite this knowledge, the concept of Guyton, which postulates that any increase in blood pressure should lead to a pressure natriuresis normalising blood pressure over the long term is still valid. As a conclusion, we have to remember that an elevation of arterial pressure can only be maintained if renal function as indicated by pressure natriuresis is impaired.
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Affiliation(s)
- Gert Mayer
- Division of Nephrology and Hypertensiology, Department of Internal Medicine IV, Innsbruck, Austria.
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