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García-Llorca A, Carta F, Supuran CT, Eysteinsson T. Carbonic anhydrase, its inhibitors and vascular function. Front Mol Biosci 2024; 11:1338528. [PMID: 38348465 PMCID: PMC10859760 DOI: 10.3389/fmolb.2024.1338528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
It has been known for some time that Carbonic Anhydrase (CA, EC 4.2.1.1) plays a complex role in vascular function, and in the regulation of vascular tone. Clinically employed CA inhibitors (CAIs) are used primarily to lower intraocular pressure in glaucoma, and also to affect retinal blood flow and oxygen saturation. CAIs have been shown to dilate vessels and increase blood flow in both the cerebral and ocular vasculature. Similar effects of CAIs on vascular function have been observed in the liver, brain and kidney, while vessels in abdominal muscle and the stomach are unaffected. Most of the studies on the vascular effects of CAIs have been focused on the cerebral and ocular vasculatures, and in particular the retinal vasculature, where vasodilation of its vessels, after intravenous infusion of sulfonamide-based CAIs can be easily observed and measured from the fundus of the eye. The mechanism by which CAIs exert their effects on the vasculature is still unclear, but the classic sulfonamide-based inhibitors have been found to directly dilate isolated vessel segments when applied to the extracellular fluid. Modification of the structure of CAI compounds affects their efficacy and potency as vasodilators. CAIs of the coumarin type, which generally are less effective in inhibiting the catalytically dominant isoform hCA II and unable to accept NO, have comparable vasodilatory effects as the primary sulfonamides on pre-contracted retinal arteriolar vessel segments, providing insights into which CA isoforms are involved. Alterations of the lipophilicity of CAI compounds affect their potency as vasodilators, and CAIs that are membrane impermeant do not act as vasodilators of isolated vessel segments. Experiments with CAIs, that shed light on the role of CA in the regulation of vascular tone of vessels, will be discussed in this review. The role of CA in vascular function will be discussed, with specific emphasis on findings with the effects of CA inhibitors (CAI).
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Affiliation(s)
- Andrea García-Llorca
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Fabrizio Carta
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Claudiu T. Supuran
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Thor Eysteinsson
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Ophthalmology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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2
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Kreitzer MA, Vredeveld M, Tinner K, Powell AM, Schantz AW, Leininger R, Merillat R, Gongwer MW, Tchernookova BK, Malchow RP. ATP-mediated increase in H + efflux from retinal Müller cells of the axolotl. J Neurophysiol 2024; 131:124-136. [PMID: 38116604 DOI: 10.1152/jn.00321.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/17/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023] Open
Abstract
Previous work has shown that activation of tiger salamander retinal radial glial cells by extracellular ATP induces a pronounced extracellular acidification, which has been proposed to be a potent modulator of neurotransmitter release. This study demonstrates that low micromolar concentrations of extracellular ATP similarly induce significant H+ effluxes from Müller cells isolated from the axolotl retina. Müller cells were enzymatically isolated from axolotl retina and H+ fluxes were measured from individual cells using self-referencing H+-selective microelectrodes. The increased H+ efflux from axolotl Müller cells induced by extracellular ATP required activation of metabotropic purinergic receptors and was dependent upon calcium released from internal stores. We further found that the ATP-evoked increase in H+ efflux from Müller cells of both tiger salamander and axolotl were sensitive to pharmacological agents known to interrupt calmodulin and protein kinase C (PKC) activity: chlorpromazine (CLP), trifluoperazine (TFP), and W-7 (all calmodulin inhibitors) and chelerythrine, a PKC inhibitor, all attenuated ATP-elicited increases in H+ efflux. ATP-initiated H+ fluxes of axolotl Müller cells were also significantly reduced by amiloride, suggesting a significant contribution by sodium-hydrogen exchangers (NHEs). In addition, α-cyano-4-hydroxycinnamate (4-cin), a monocarboxylate transport (MCT) inhibitor, also reduced the ATP-induced increase in H+ efflux in both axolotl and tiger salamander Müller cells, and when combined with amiloride, abolished ATP-evoked increase in H+ efflux. These data suggest that axolotl Müller cells are likely to be an excellent model system to understand the cell-signaling pathways regulating H+ release from glia and the role this may play in modulating neuronal signaling.NEW & NOTEWORTHY Glial cells are a key structural part of the tripartite synapse and have been suggested to regulate synaptic transmission, but the regulatory mechanisms remain unclear. We show that extracellular ATP, a potent glial cell activator, induces H+ efflux from axolotl retinal Müller (glial) cells through a calcium-dependent pathway that is likely to involve calmodulin, PKC, Na+/H+ exchange, and monocarboxylate transport, and suggest that such H+ release may play a key role in modulating neuronal transmission.
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Affiliation(s)
- Matthew A Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Mason Vredeveld
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Kaleb Tinner
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Alyssa M Powell
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Adam W Schantz
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Rachel Leininger
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Rajapone Merillat
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Michael W Gongwer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Boriana K Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
- Department of Psychology, College of the Holy Cross, Worcester, Massachusetts, United States
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Tkachenko Y, Khmyz V, Buta A, Isaev D, Maximyuk O, Krishtal O. Acid-sensing ion channel blocker diminazene facilitates proton-induced excitation of afferent nerves in a similar manner that Na +/H + exchanger blockers do. Front Cell Neurosci 2023; 17:1131661. [PMID: 37502464 PMCID: PMC10368877 DOI: 10.3389/fncel.2023.1131661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 06/26/2023] [Indexed: 07/29/2023] Open
Abstract
Tissue acidification causes sustained activation of primary nociceptors, which causes pain. In mammals, acid-sensing ion channels (ASICs) are the primary acid sensors; however, Na+/H+ exchangers (NHEs) and TRPV1 receptors also contribute to tissue acidification sensing. ASICs, NHEs, and TRPV1 receptors are found to be expressed in nociceptive nerve fibers. ASIC inhibitors reduce peripheral acid-induced hyperalgesia and suppress inflammatory pain. Also, it was shown that pharmacological inhibition of NHE1 promotes nociceptive behavior in acute pain models, whereas inhibition of TRPV1 receptors gives relief. The murine skin-nerve preparation was used in this study to assess the activation of native polymodal nociceptors by mild acidification (pH 6.1). We have found that diminazene, a well-known antagonist of ASICs did not suppress pH-induced activation of CMH-fibers at concentrations as high as 25 μM. Moreover, at 100 μM, it induces the potentiation of the fibers' response to acidic pH. At the same time, this concentration virtually completely inhibited ASIC currents in mouse dorsal root ganglia (DRG) neurons (IC50 = 17.0 ± 4.5 μM). Non-selective ASICs and NHEs inhibitor EIPA (5-(N-ethyl-N-isopropyl)amiloride) at 10 μM, as well as selective NHE1 inhibitor zoniporide at 0.5 μM induced qualitatively the same effects as 100 μM of diminazene. Our results indicate that excitation of afferent nerve terminals induced by mild acidification occurs mainly due to the NHE1, rather than acid-sensing ion channels. At high concentrations, diminazene acts as a weak blocker of the NHE. It lacks chemical similarity with amiloride, EIPA, and zoniporide, so it may represent a novel structural motif for the development of NHE antagonists. However, the effect of diminazene on the acid-induced excitation of primary nociceptors remains enigmatic and requires additional investigations.
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Dausinas Ni P, Hartman M, Slack J, Basile C, Liu S, Wan J, O'Leary HA. Novel differential calcium regulation of hematopoietic stem and progenitor cells under physiological low oxygen conditions. J Cell Physiol 2023. [PMID: 37051890 DOI: 10.1002/jcp.30942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 11/28/2022] [Accepted: 12/23/2022] [Indexed: 04/14/2023]
Abstract
Low oxygen bone marrow (BM) niches (~1%-4% low O2 ) provide critical signals for hematopoietic stem/progenitor cells (HSC/HSPCs). Our presented data are the first to investigate live, sorted HSC/HSPCs in their native low O2 conditions. Transcriptional and proteomic analysis uncovered differential Ca2+ regulation that correlated with overlapping phenotypic populations consisting of robust increases of cytosolic and mitochondrial Ca2+ , ABC transporter (ABCG2) expression and sodium/hydrogen exchanger (NHE1) expression in live, HSC/HSPCs remaining in constant low O2. We identified a novel Ca2+ high population in HSPCs predominantly detected in low O2 that displayed enhanced frequency of phenotypic LSK/LSKCD150 in low O2 replating assays compared to Ca2+ low populations. Inhibition of the Ca2+ regulator NHE1 (Cariporide) resulted in attenuation of both the low O2 induced Ca2+ high population and subsequent enhanced maintenance of phenotypic LSK and LSKCD150 during low O2 replating. These data reveal multiple levels of differential Ca2+ regulation in low O2 resulting in phenotypic, signaling, and functional consequences in HSC/HSPCs.
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Affiliation(s)
- Paige Dausinas Ni
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Melissa Hartman
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jacob Slack
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Christopher Basile
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sheng Liu
- Department of Medical and Molecular Genetics, Center of Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jun Wan
- Department of Medical and Molecular Genetics, Center of Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Heather A O'Leary
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA
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5
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The SLC9C2 Gene Product (Na+/H+ Exchanger Isoform 11; NHE11) Is a Testis-Specific Protein Localized to the Head of Mature Mammalian Sperm. Int J Mol Sci 2023; 24:ijms24065329. [PMID: 36982403 PMCID: PMC10049371 DOI: 10.3390/ijms24065329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/02/2023] [Accepted: 03/07/2023] [Indexed: 03/14/2023] Open
Abstract
Na+/H+ exchangers (NHEs) are a family of ion transporters that regulate the pH of various cell compartments across an array of cell types. In eukaryotes, NHEs are encoded by the SLC9 gene family comprising 13 genes. SLC9C2, which encodes the NHE11 protein, is the only one of the SLC9 genes that is essentially uncharacterized. Here, we show that SLC9C2 exhibits testis/sperm-restricted expression in rats and humans, akin to its paralog SLC9C1 (NHE10). Similar to NHE10, NHE11 is predicted to contain an NHE domain, a voltage sensing domain, and finally an intracellular cyclic nucleotide binding domain. An immunofluorescence analysis of testis sections reveals that NHE11 localizes with developing acrosomal granules in spermiogenic cells in both rat and human testes. Most interestingly, NHE11 localizes to the sperm head, likely the plasma membrane overlaying the acrosome, in mature sperm from rats and humans. Therefore, NHE11 is the only known NHE to localize to the acrosomal region of the head in mature sperm cells. The physiological role of NHE11 has yet to be demonstrated but its predicted functional domains and unique localization suggests that it could modulate intracellular pH of the sperm head in response to changes in membrane potential and cyclic nucleotide concentrations that are a result of sperm capacitation events. If NHE11 is shown to be important for male fertility, it will be an attractive target for male contraceptive drugs due to its exclusive testis/sperm-specific expression.
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Li X, Yang Y, Zhang B, Lin X, Fu X, An Y, Zou Y, Wang JX, Wang Z, Yu T. Lactate metabolism in human health and disease. Signal Transduct Target Ther 2022; 7:305. [PMID: 36050306 PMCID: PMC9434547 DOI: 10.1038/s41392-022-01151-3] [Citation(s) in RCA: 213] [Impact Index Per Article: 106.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 07/17/2022] [Accepted: 08/09/2022] [Indexed: 12/29/2022] Open
Abstract
The current understanding of lactate extends from its origins as a byproduct of glycolysis to its role in tumor metabolism, as identified by studies on the Warburg effect. The lactate shuttle hypothesis suggests that lactate plays an important role as a bridging signaling molecule that coordinates signaling among different cells, organs and tissues. Lactylation is a posttranslational modification initially reported by Professor Yingming Zhao’s research group in 2019. Subsequent studies confirmed that lactylation is a vital component of lactate function and is involved in tumor proliferation, neural excitation, inflammation and other biological processes. An indispensable substance for various physiological cellular functions, lactate plays a regulatory role in different aspects of energy metabolism and signal transduction. Therefore, a comprehensive review and summary of lactate is presented to clarify the role of lactate in disease and to provide a reference and direction for future research. This review offers a systematic overview of lactate homeostasis and its roles in physiological and pathological processes, as well as a comprehensive overview of the effects of lactylation in various diseases, particularly inflammation and cancer.
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Affiliation(s)
- Xiaolu Li
- Center for Regenerative Medicine, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University; Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, China
| | - Yanyan Yang
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Bei Zhang
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Xiaotong Lin
- Department of Respiratory Medicine, Qingdao Municipal Hospital, Qingdao, 266011, China
| | - Xiuxiu Fu
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, China
| | - Yi An
- Department of Cardiology, The Affiliated Hospital of Qingdao University, No. 1677 Wutaishan Road, Qingdao, 266555, China
| | - Yulin Zou
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, China
| | - Jian-Xun Wang
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Zhibin Wang
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, China.
| | - Tao Yu
- Center for Regenerative Medicine, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University; Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, China.
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7
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Matsuoka R, Fudim R, Jung S, Zhang C, Bazzone A, Chatzikyriakidou Y, Robinson CV, Nomura N, Iwata S, Landreh M, Orellana L, Beckstein O, Drew D. Structure, mechanism and lipid-mediated remodeling of the mammalian Na +/H + exchanger NHA2. Nat Struct Mol Biol 2022; 29:108-120. [PMID: 35173351 PMCID: PMC8850199 DOI: 10.1038/s41594-022-00738-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 12/14/2021] [Indexed: 11/09/2022]
Abstract
The Na+/H+ exchanger SLC9B2, also known as NHA2, correlates with the long-sought-after Na+/Li+ exchanger linked to the pathogenesis of diabetes mellitus and essential hypertension in humans. Despite the functional importance of NHA2, structural information and the molecular basis for its ion-exchange mechanism have been lacking. Here we report the cryo-EM structures of bison NHA2 in detergent and in nanodiscs, at 3.0 and 3.5 Å resolution, respectively. The bison NHA2 structure, together with solid-state membrane-based electrophysiology, establishes the molecular basis for electroneutral ion exchange. NHA2 consists of 14 transmembrane (TM) segments, rather than the 13 TMs previously observed in mammalian Na+/H+ exchangers (NHEs) and related bacterial antiporters. The additional N-terminal helix in NHA2 forms a unique homodimer interface with a large intracellular gap between the protomers, which closes in the presence of phosphoinositol lipids. We propose that the additional N-terminal helix has evolved as a lipid-mediated remodeling switch for the regulation of NHA2 activity.
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Affiliation(s)
- Rei Matsuoka
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Roman Fudim
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
| | - Sukkyeong Jung
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Chenou Zhang
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ, USA
| | | | | | | | - Norimichi Nomura
- Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, Japan
| | - So Iwata
- Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, Japan
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Laura Orellana
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Oliver Beckstein
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ, USA.
| | - David Drew
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
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8
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Takatani-Nakase T, Matsui C, Hosotani M, Omura M, Takahashi K, Nakase I. Hypoxia enhances motility and EMT through the Na +/H + exchanger NHE-1 in MDA-MB-231 breast cancer cells. Exp Cell Res 2022; 412:113006. [PMID: 34979106 DOI: 10.1016/j.yexcr.2021.113006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/23/2021] [Accepted: 12/30/2021] [Indexed: 12/15/2022]
Abstract
Breast cancer metastasis is the leading cause of cancer-related deaths. Hypoxia in the tumor mass is believed to trigger cell migration, which is involved in a crucial process of breast cancer metastasis. However, the molecular mechanisms underlying aggressive behavior under hypoxic conditions have not been fully elucidated. Here, we demonstrate the significant motility of MDA-MB-231 cells cultured under hypoxic conditions compared to that of cells cultured under normoxic conditions. MDA-MB-231 cells under hypoxic conditions showed a significant increase in Na+/H+ exchanger isoform 1 (NHE1) expression level, which was observed to co-locate in lamellipodia formation. Inhibition of NHE1 significantly suppressed the intracellular pH and the expression of mesenchymal markers, thereby blocking the high migration activity in hypoxia. Moreover, treatment with ciglitazone, a potent and selective peroxisome proliferator-activated receptor γ (PPARγ) agonist, modulated hypoxia-enhanced motion in cells via the repression of NHE1. These findings highlight that NHE1 is required for migratory activity through the enhancement of epithelial-mesenchymal transition (EMT) in MDA-MB-231 cells under hypoxic conditions, and we propose new drug repurposing strategies targeting hypoxia based on NHE1 suppression by effective usage of PPARγ agonists.
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Affiliation(s)
- Tomoka Takatani-Nakase
- Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya, Hyogo, 663-8179, Japan; Institute for Bioscience, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya, Hyogo, 663-8179, Japan.
| | - Chihiro Matsui
- Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya, Hyogo, 663-8179, Japan
| | - Maiko Hosotani
- Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya, Hyogo, 663-8179, Japan
| | - Mika Omura
- Graduate School of Science, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Koichi Takahashi
- Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya, Hyogo, 663-8179, Japan
| | - Ikuhiko Nakase
- Graduate School of Science, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan; NanoSquare Research Institute, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8570, Japan.
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9
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Donahue CET, Siroky MD, White KA. An Optogenetic Tool to Raise Intracellular pH in Single Cells and Drive Localized Membrane Dynamics. J Am Chem Soc 2021; 143:18877-18887. [PMID: 34726911 PMCID: PMC8603357 DOI: 10.1021/jacs.1c02156] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
![]()
Intracellular pH
(pHi) dynamics are critical for regulating normal
cell physiology. For example, transient increases in pHi (7.2–7.6)
regulate cell behaviors like cell polarization, actin cytoskeleton
remodeling, and cell migration. Most studies on pH-dependent cell
behaviors have been performed at the population level and use nonspecific
methods to manipulate pHi. The lack of tools to specifically manipulate
pHi at the single-cell level has hindered investigation of the role
of pHi dynamics in driving single cell behaviors. In this work, we
show that Archaerhodopsin (ArchT), a light-driven outward proton pump,
can be used to elicit robust and physiological pHi increases over
the minutes time scale. We show that activation of ArchT is repeatable,
enabling the maintenance of high pHi in single cells for up to 45
minutes. We apply this spatiotemporal pHi manipulation tool to determine
whether increased pHi is a sufficient driver of membrane ruffling
in single cells. Using the ArchT tool, we show that increased pHi
in single cells can drive localized membrane ruffling responses within
seconds and increased membrane dynamics (both protrusion and retraction
events) compared to unstimulated ArchT cells as well as control cells.
Overall, this tool allows us to directly investigate the relationship
between increased pHi and single cell behaviors such as membrane ruffling.
This tool will be transformative in facilitating experiments that
are required to determine roles for increased pHi in driving single
cell behaviors.
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Affiliation(s)
- Caitlin E T Donahue
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46617, United States
| | - Michael D Siroky
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46617, United States
| | - Katharine A White
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46617, United States
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10
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Korsós MM, Bellák T, Becskeházi E, Gál E, Veréb Z, Hegyi P, Venglovecz V. Mouse organoid culture is a suitable model to study esophageal ion transport mechanisms. Am J Physiol Cell Physiol 2021; 321:C798-C811. [PMID: 34524930 DOI: 10.1152/ajpcell.00295.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/08/2021] [Indexed: 11/22/2022]
Abstract
Altered esophageal ion transport mechanisms play a key role in inflammatory and cancerous diseases of the esophagus, but epithelial ion processes have been less studied in the esophagus because of the lack of a suitable experimental model. In this study, we generated three-dimensional (3D) esophageal organoids (EOs) from two different mouse strains and characterized the ion transport processes of the EOs. EOs form a cell-filled structure with a diameter of 250-300 µm and were generated from epithelial stem cells as shown by FACS analysis. Using conventional PCR and immunostaining, the presence of Slc26a6 Cl-/HCO3- anion exchanger (AE), Na+/H+ exchanger (NHE), Na+/HCO3- cotransporter (NBC), cystic fibrosis transmembrane conductance regulator (CFTR), and anoctamin 1 Cl- channels was detected in EOs. Microfluorimetric techniques revealed high NHE, AE, and NBC activities, whereas that of CFTR was relatively low. In addition, inhibition of CFTR led to functional interactions between the major acid-base transporters and CFTR. We conclude that EOs provide a relevant and suitable model system for studying the ion transport mechanisms of esophageal epithelial cells, and they can be also used as preclinical tools to assess the effectiveness of novel therapeutic compounds in esophageal diseases associated with altered ion transport processes.
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Affiliation(s)
| | - Tamás Bellák
- Department of Anatomy, Histology and Embryology, University of Szeged, Szeged, Hungary
- BioTalentum Ltd., Gödöllő, Hungary
| | - Eszter Becskeházi
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Eleonóra Gál
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Zoltán Veréb
- Regenerative Medicine and Cellular Pharmacology Research Laboratory, Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- First Department of Medicine, University of Szeged, Szeged, Hungary
- Szentágothai Research Centre, Institute for Translational Medicine, Medical School, University of Pécs, Pécs, Hungary
- Division of Gastroenterology, First Department of Medicine, Medical School, University of Pécs, Pécs, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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11
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Chen YL, Ren Y, Rosa RH, Kuo L, Hein TW. Contributions of Sodium-Hydrogen Exchanger 1 and Mitogen-Activated Protein Kinases to Enhanced Retinal Venular Constriction to Endothelin-1 in Diabetes. Diabetes 2021; 70:2353-2363. [PMID: 34353852 PMCID: PMC8576499 DOI: 10.2337/db20-0889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 07/28/2021] [Indexed: 11/13/2022]
Abstract
Diabetes elevates endothelin-1 (ET-1) in the vitreous and enhances constriction of retinal venules to this peptide. However, mechanisms contributing to ET-1-induced constriction of retinal venules are incompletely understood. We examined roles of sodium-hydrogen exchanger 1 (NHE1), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and extracellular calcium (Ca2+) in retinal venular constriction to ET-1 and the impact of diabetes on these signaling molecules. Retinal venules were isolated from control pigs and pigs with streptozocin-induced diabetes for in vitro studies. ET-1-induced vasoconstriction was abolished in the absence of extracellular Ca2+ and sensitive to c-Jun N-terminal kinase (JNK) inhibitor SP600125 but unaffected by extracellular signal-regulated kinase (ERK) inhibitor PD98059, p38 kinase inhibitor SB203580, or broad-spectrum PKC inhibitor Gö 6983. Diabetes (after 2 weeks) enhanced venular constriction to ET-1, which was insensitive to PD98059 and Gö 6983 but was prevented by NHE1 inhibitor cariporide, SB203580, and SP600125. In conclusion, extracellular Ca2+ entry and activation of JNK, independent of ERK and PKC, mediate constriction of retinal venules to ET-1. Diabetes activates p38 MAPK and NHE1, which cause enhanced venular constriction to ET-1. Treatments targeting these vascular molecules may lessen retinal complications in early diabetes.
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Affiliation(s)
- Yen-Lin Chen
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Yi Ren
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Robert H Rosa
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
- Department of Ophthalmology, Baylor Scott & White Eye Institute, Temple, TX
| | - Lih Kuo
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Travis W Hein
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
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12
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Dong Y, Gao Y, Ilie A, Kim D, Boucher A, Li B, Zhang XC, Orlowski J, Zhao Y. Structure and mechanism of the human NHE1-CHP1 complex. Nat Commun 2021; 12:3474. [PMID: 34108458 PMCID: PMC8190280 DOI: 10.1038/s41467-021-23496-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/29/2021] [Indexed: 02/05/2023] Open
Abstract
Sodium/proton exchanger 1 (NHE1) is an electroneutral secondary active transporter present on the plasma membrane of most mammalian cells and plays critical roles in regulating intracellular pH and volume homeostasis. Calcineurin B-homologous protein 1 (CHP1) is an obligate binding partner that promotes NHE1 biosynthetic maturation, cell surface expression and pH-sensitivity. Dysfunctions of either protein are associated with neurological disorders. Here, we elucidate structures of the human NHE1-CHP1 complex in both inward- and inhibitor (cariporide)-bound outward-facing conformations. We find that NHE1 assembles as a symmetrical homodimer, with each subunit undergoing an elevator-like conformational change during cation exchange. The cryo-EM map reveals the binding site for the NHE1 inhibitor cariporide, illustrating how inhibitors block transport activity. The CHP1 molecule differentially associates with these two conformational states of each NHE1 monomer, and this association difference probably underlies the regulation of NHE1 pH-sensitivity by CHP1.
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Affiliation(s)
- Yanli Dong
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yiwei Gao
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Alina Ilie
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - DuSik Kim
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Annie Boucher
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Bin Li
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xuejun C. Zhang
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - John Orlowski
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Yan Zhao
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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13
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Kinaneh S, Knany Y, Khoury EE, Ismael-Badarneh R, Hamoud S, Berger G, Abassi Z, Azzam ZS. Identification, localization and expression of NHE isoforms in the alveolar epithelial cells. PLoS One 2021; 16:e0239240. [PMID: 33882062 PMCID: PMC8059851 DOI: 10.1371/journal.pone.0239240] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 04/02/2021] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers (NHEs), encoded by Solute Carrier 9A (SLC9A) genes in human, are ubiquitous integral membrane ion transporters that mediate the electroneutral exchange of H+ with Na+ or K+. NHEs, found in the kidney and intestine, play a major role in the process of fluid reabsorption together via Na+,K+-ATPase pump and Na+ channels. Nevertheless, the expression pattern of NHE in the lung and its role in alveolar fluid homeostasis has not been addressed. Therefore, we aimed to examine the expression of NHE specific isoforms in alveolar epithelial cells (AECs), and assess their role in congestive heart failure (CHF). Three NHE isoforms were identified in AEC and A549 cell line, at the level of protein and mRNA; NHE1, NHE2 and mainly NHE8, the latter was shown to be localized in the apical membrane of AEC. Treating A549 cells with angiotensin (Ang) II for 3, 5 and 24 hours displayed a significant reduction in NHE8 protein abundance. Moreover, the abundance of NHE8 protein was downregulated in A549 cells that were treated overnight with Ang II. NHE8 abundance in whole lung lysate was increased in rats with 1-week CHF compared to sham operated rats. However, lower abundance of NHE8 was observed in 4-week CHF group. In conclusion, we herein show for the first time, the expression of a novel NHE isoform in AEC, namely NHE8. Notably, Ang II decreased NHE8 protein levels. Moreover, NHE8 was distinctly affected in CHF rats, probably depending on the severity of the heart failure.
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Affiliation(s)
- Safa Kinaneh
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
| | - Yara Knany
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
| | - Emad E. Khoury
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
| | | | - Shadi Hamoud
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
- Internal Medicine “E”, Rambam: Human Health Care Campus, Haifa, Israel
| | - Gidon Berger
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
- Internal Medicine “B”, Rambam: Human Health Care Campus, Haifa, Israel
| | - Zaid Abassi
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
| | - Zaher S. Azzam
- Ruth & Bruce Rappaport Faculty of Medicine, Department of Physiology, Technion, Israel Institute of Technology, Haifa, Israel
- Internal Medicine “B”, Rambam: Human Health Care Campus, Haifa, Israel
- * E-mail:
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14
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Buckley BJ, Kumar A, Aboelela A, Bujaroski RS, Li X, Majed H, Fliegel L, Ranson M, Kelso MJ. Screening of 5- and 6-Substituted Amiloride Libraries Identifies Dual-uPA/NHE1 Active and Single Target-Selective Inhibitors. Int J Mol Sci 2021; 22:ijms22062999. [PMID: 33804289 PMCID: PMC8000185 DOI: 10.3390/ijms22062999] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/05/2021] [Accepted: 03/06/2021] [Indexed: 12/13/2022] Open
Abstract
The K+-sparing diuretic amiloride shows off-target anti-cancer effects in multiple rodent models. These effects arise from the inhibition of two distinct cancer targets: the trypsin-like serine protease urokinase-type plasminogen activator (uPA), a cell-surface mediator of matrix degradation and tumor cell invasiveness, and the sodium-hydrogen exchanger isoform-1 (NHE1), a central regulator of transmembrane pH that supports carcinogenic progression. In this study, we co-screened our library of 5- and 6-substituted amilorides against these two targets, aiming to identify single-target selective and dual-targeting inhibitors for use as complementary pharmacological probes. Closely related analogs substituted at the 6-position with pyrimidines were identified as dual-targeting (pyrimidine 24 uPA IC50 = 175 nM, NHE1 IC50 = 266 nM, uPA selectivity ratio = 1.5) and uPA-selective (methoxypyrimidine 26 uPA IC50 = 86 nM, NHE1 IC50 = 12,290 nM, uPA selectivity ratio = 143) inhibitors, while high NHE1 potency and selectivity was seen with 5-morpholino (29 NHE1 IC50 = 129 nM, uPA IC50 = 10,949 nM; NHE1 selectivity ratio = 85) and 5-(1,4-oxazepine) (30 NHE1 IC50 = 85 nM, uPA IC50 = 5715 nM; NHE1 selectivity ratio = 67) analogs. Together, these amilorides comprise a new toolkit of chemotype-matched, non-cytotoxic probes for dissecting the pharmacological effects of selective uPA and NHE1 inhibition versus dual-uPA/NHE1 inhibition.
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Affiliation(s)
- Benjamin J. Buckley
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- CONCERT-Translational Cancer Research Centre, Sydney, NSW 2750, Australia
- Correspondence: (B.J.B.); (M.J.K.); Tel.: +61-2-4221-5085 (M.J.K.)
| | - Ashna Kumar
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Ashraf Aboelela
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Richard S. Bujaroski
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (L.F.)
| | - Hiwa Majed
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (L.F.)
| | - Marie Ranson
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- CONCERT-Translational Cancer Research Centre, Sydney, NSW 2750, Australia
| | - Michael J. Kelso
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (A.K.); (A.A.); (R.S.B.); (H.M.); (M.R.)
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- Correspondence: (B.J.B.); (M.J.K.); Tel.: +61-2-4221-5085 (M.J.K.)
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15
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Ware AW, Harris JJ, Slatter TL, Cunliffe HE, McDonald FJ. The epithelial sodium channel has a role in breast cancer cell proliferation. Breast Cancer Res Treat 2021; 187:31-43. [PMID: 33630195 DOI: 10.1007/s10549-021-06133-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 02/05/2021] [Indexed: 01/22/2023]
Abstract
PURPOSE Breast cancer is the most common cancer affecting women worldwide with half a million associated deaths annually. Despite a huge global effort, the pathways of breast cancer progression are not fully elucidated. Ion channels have recently emerged as novel regulators of cancer cell proliferation and metastasis. The epithelial sodium channel, ENaC, made up of α, β and γ subunits is well known for its role in Na+ reabsorption in epithelia, but a number of novel roles for ENaC have been described, including potential roles in cancer. A role for ENaC in breast cancer, however, has yet to be described. Therefore, the effects of ENaC level and activity on breast cancer proliferation were investigated. METHODS Through the publicly available SCAN-B dataset associations between αENaC mRNA expression and breast cancer subtypes, proliferation markers and epithelial-mesenchymal transition markers (EMT) were assessed. αENaC expression, through overexpression or siRNA-mediated knockdown, and activity, through the ENaC-specific inhibitor amiloride, were altered in MCF7, T47D, BT549, and MDAMB231 breast cancer cells. MTT and EdU cell proliferation assays were used to determine the effect of these manipulations on breast cancer cell proliferation. RESULTS High αENaC mRNA expression was associated with less aggressive and less proliferative breast cancer subtypes and with reduced expression of proliferation markers. Decreased αENaC expression or activity, in the mesenchymal breast cancer cell lines BT549 and MDAMB231, increased breast cancer cell proliferation. Conversely, increased αENaC expression decreased breast cancer cell proliferation. CONCLUSION αENaC expression is associated with a poor prognosis in breast cancer and is a novel regulator of breast cancer cell proliferation. Taken together, these results identify ENaC as a potential future therapeutic target.
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Affiliation(s)
- Adam W Ware
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Joshua J Harris
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Tania L Slatter
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Heather E Cunliffe
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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16
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Blair S, Li X, Dutta D, Chamot D, Fliegel L, Goss G. Rainbow Trout ( Oncorhynchus mykiss) Na +/H + Exchangers tNhe3a and tNhe3b Display Unique Inhibitory Profiles Dissimilar from Mammalian NHE Isoforms. Int J Mol Sci 2021; 22:ijms22042205. [PMID: 33672216 PMCID: PMC7926675 DOI: 10.3390/ijms22042205] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/17/2021] [Accepted: 02/20/2021] [Indexed: 01/05/2023] Open
Abstract
Freshwater fishes maintain an internal osmolality of ~300 mOsm, while living in dilute environments ranging from 0 to 50 mOsm. This osmotic challenge is met at least partially, by Na+/H+ exchangers (NHE) of fish gill and kidney. In this study, we cloned, expressed, and pharmacologically characterized fish-specific Nhes of the commercially important species Oncorhynchus mykiss. Trout (t) Nhe3a and Nhe3b isoforms from gill and kidney were expressed and characterized in an NHE-deficient cell line. Western blotting and immunocytochemistry confirmed stable expression of the tagged trout tNhe proteins. To measure NHE activity, a transient acid load was induced in trout tNhe expressing cells and intracellular pH was measured. Both isoforms demonstrated significant activity and recovered from an acute acid load. The effect of the NHE transport inhibitors amiloride, EIPA (5-(N-ethyl-N-isopropyl)-amiloride), phenamil, and DAPI was examined. tNhe3a was inhibited in a dose-dependent manner by amiloride and EIPA and tNhe3a was more sensitive to amiloride than EIPA, unlike mammalian NHE1. tNhe3b was inhibited by high concentrations of amiloride, while even in the presence of high concentrations of EIPA (500 µM), some activity of tNhe3b remained. Phenamil and DAPI were ineffective at inhibiting tNhe activity of either isoform. The current study aids in understanding the pharmacology of fish ion transporters. Both isoforms display inhibitory profiles uniquely different from mammalian NHEs and show resistance to inhibition. Our study allows for more direct interpretation of past, present, and future fish-specific sodium transport studies, with less reliance on mammalian NHE data for interpretation.
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Affiliation(s)
- Salvatore Blair
- Department of Biology, Winthrop University, Rock Hill, SC 29733, USA;
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada;
| | - Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (D.D.); (L.F.)
| | - Debajyoti Dutta
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (D.D.); (L.F.)
| | - Danuta Chamot
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada;
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; (X.L.); (D.D.); (L.F.)
| | - Greg Goss
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada;
- Correspondence: ; Tel.: +1-780-492-1276; Fax: +1-780-492-9234
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17
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Sanidas E, Velliou M, Papadopoulos D, Fotsali A, Iliopoulos D, Mantzourani M, Toutouzas K, Barbetseas J. Antihypertensive Drugs and Risk of Cancer: Between Scylla and Charybdis. Am J Hypertens 2020; 33:1049-1058. [PMID: 32529212 DOI: 10.1093/ajh/hpaa098] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 12/14/2022] Open
Abstract
Antihypertensive drugs namely angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, beta blockers, and diuretics are among the most clearly documented regimens worldwide with an overall cardioprotective benefit. Given that malignancy is the second leading cause of mortality, numerous observational studies aimed to investigate the carcinogenic potential of these agents with conflicting results. The purpose of this review was to summarize current data in an effort to explore rare side effects and new mechanisms linking antihypertensive drugs with the risk of developing cancer.
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Affiliation(s)
- Elias Sanidas
- Hypertension Excellence Centre—ESH, Department of Cardiology, LAIKO General Hospital, Athens, Greece
| | - Maria Velliou
- Hypertension Excellence Centre—ESH, Department of Cardiology, LAIKO General Hospital, Athens, Greece
| | - Dimitrios Papadopoulos
- Hypertension Excellence Centre—ESH, Department of Cardiology, LAIKO General Hospital, Athens, Greece
| | - Anastasia Fotsali
- Hypertension Excellence Centre—ESH, Department of Cardiology, LAIKO General Hospital, Athens, Greece
| | - Dimitrios Iliopoulos
- Laboratory of Experimental Surgery and Surgical Research “N.S. Christeas”, University of Athens, Medical School, Athens, Greece
| | - Marina Mantzourani
- 1st Department of Internal Medicine, LAIKO General Hospital, University of Athens, Medical School, Athens, Greece
| | - Konstantinos Toutouzas
- University of Athens, 1st Department of Cardiology, Hippokrateion Hospital, Athens, Greece
| | - John Barbetseas
- Hypertension Excellence Centre—ESH, Department of Cardiology, LAIKO General Hospital, Athens, Greece
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18
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Winklemann I, Matsuoka R, Meier PF, Shutin D, Zhang C, Orellana L, Sexton R, Landreh M, Robinson CV, Beckstein O, Drew D. Structure and elevator mechanism of the mammalian sodium/proton exchanger NHE9. EMBO J 2020; 39:e105908. [PMID: 33118634 PMCID: PMC7737618 DOI: 10.15252/embj.2020105908] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/21/2022] Open
Abstract
Na+ /H+ exchangers (NHEs) are ancient membrane-bound nanomachines that work to regulate intracellular pH, sodium levels and cell volume. NHE activities contribute to the control of the cell cycle, cell proliferation, cell migration and vesicle trafficking. NHE dysfunction has been linked to many diseases, and they are targets of pharmaceutical drugs. Despite their fundamental importance to cell homeostasis and human physiology, structural information for the mammalian NHE was lacking. Here, we report the cryogenic electron microscopy structure of NHE isoform 9 (SLC9A9) from Equus caballus at 3.2 Å resolution, an endosomal isoform highly expressed in the brain and associated with autism spectrum (ASD) and attention deficit hyperactivity (ADHD) disorders. Despite low sequence identity, the NHE9 architecture and ion-binding site are remarkably similar to distantly related bacterial Na+ /H+ antiporters with 13 transmembrane segments. Collectively, we reveal the conserved architecture of the NHE ion-binding site, their elevator-like structural transitions, the functional implications of autism disease mutations and the role of phosphoinositide lipids to promote homodimerization that, together, have important physiological ramifications.
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Affiliation(s)
- Iven Winklemann
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Rei Matsuoka
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Pascal F Meier
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Denis Shutin
- Department of ChemistryUniversity of OxfordOxfordUK
| | - Chenou Zhang
- Department of PhysicsCenter for Biological PhysicsArizona State UniversityTempeAZUSA
| | - Laura Orellana
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
| | - Ricky Sexton
- Department of PhysicsCenter for Biological PhysicsArizona State UniversityTempeAZUSA
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstituteStockholmSweden
| | | | - Oliver Beckstein
- Department of PhysicsCenter for Biological PhysicsArizona State UniversityTempeAZUSA
| | - David Drew
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
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19
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Guo Y, Lu Y, Wang J, Zhu L, Liu X. Dysregulated ion channels and transporters activate endoplasmic reticulum stress in rat kidney of fetal growth restriction. Life Sci 2020; 259:118276. [PMID: 32798560 DOI: 10.1016/j.lfs.2020.118276] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 12/30/2022]
Abstract
AIMS The mechanisms underlying the fetal origin of renal disease remains unknown. This study aimed to investigate the profiles of ion channel and transporter proteins in the fetal kidney in fetal growth restriction (FGR)rats, and to explore their association with the fetal origin of renal disease. MAIN METHODS An FGR rat model was developed by administration of a low-protein diet. Then 367 differentially expressed proteins (DEPs) from quantitative proteome analysis were subjected to Ingenuity Pathway Analysis. 22 DEPs associated with ion channels/transporters were evaluated in the fetal kidney. Na+/H+ exchanger1(NHE1) and its downstream unfolded protein response (UPR) pathway were investigated. Furthermore, overexpression of NHE1 were achieved via plasmid transfection to evaluate the potential influence on the UPR pathway and cell apoptosis in human proximal tubular epithelial cell line HK2 cells. KEY FINDINGS Findings were as follows: 1) In the FGR fetal kidney, aquaporin 2/4, solute carrier (SLC) 8a1, 33a1, etc. were downregulated, whereas other transporters including SLC 2a1, 4a1, 9a1, 29a3, etc. were upregulated. 2) NHE1 mRNA levels were markedly elevated in the FGR fetus. Further investigation revealed an increase in the UPR pathway regulators. 3) In vitro study showed that NHE1 overexpression in HK2 cells significantly induced expression of the endoplasmic reticulum stress (ERS) regulators and led to a decrease in the anti-apoptotic potential. SIGNIFICANCE We speculate that maternal protein malnutrition causes dysregulation of ion channels/transporters in the fetal kidney. Upregulated NHE1 may activate the UPR pathway and induce cell apoptosis thus leading to impairment of kidney function.
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Affiliation(s)
- Yanyan Guo
- Key Laboratory of maternal-fetal medicine of Liaoning Province, Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, China
| | - Yan Lu
- Department of human resource, Shengjing Hospital of China Medical University, China
| | - Jun Wang
- Key Laboratory of maternal-fetal medicine of Liaoning Province, Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, China
| | - Liangliang Zhu
- Key Laboratory of maternal-fetal medicine of Liaoning Province, Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, China
| | - Xiaomei Liu
- Key Laboratory of maternal-fetal medicine of Liaoning Province, Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, China.
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Becskeházi E, Korsós MM, Erőss B, Hegyi P, Venglovecz V. OEsophageal Ion Transport Mechanisms and Significance Under Pathological Conditions. Front Physiol 2020; 11:855. [PMID: 32765303 PMCID: PMC7379034 DOI: 10.3389/fphys.2020.00855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/25/2020] [Indexed: 12/20/2022] Open
Abstract
Ion transporters play an important role in several physiological functions, such as cell volume regulation, pH homeostasis and secretion. In the oesophagus, ion transport proteins are part of the epithelial resistance, a mechanism which protects the oesophagus against reflux-induced damage. A change in the function or expression of ion transporters has significance in the development or neoplastic progression of Barrett’s oesophagus (BO). In this review, we discuss the physiological and pathophysiological roles of ion transporters in the oesophagus, highlighting transport proteins which serve as therapeutic targets or prognostic markers in eosinophilic oesophagitis, BO and esophageal cancer. We believe that this review highlights important relationships which might contribute to a better understanding of the pathomechanisms of esophageal diseases.
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Affiliation(s)
- Eszter Becskeházi
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | | | - Bálint Erőss
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Hegyi
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary.,Division of Gastroenterology, First Department of Medicine, Medical School, University of Pécs, Pécs, Hungary.,First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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21
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Patak J, Faraone SV, Zhang-James Y. Sodium hydrogen exchanger 9 NHE9 (SLC9A9) and its emerging roles in neuropsychiatric comorbidity. Am J Med Genet B Neuropsychiatr Genet 2020; 183:289-305. [PMID: 32400953 DOI: 10.1002/ajmg.b.32787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 12/09/2019] [Accepted: 02/22/2020] [Indexed: 12/16/2022]
Abstract
Variations in SLC9A9 gene expression and protein function are associated with multiple human diseases, which range from Attention-deficit/hyperactivity disorder (ADHD) to glioblastoma multiforme. In an effort to determine the full spectrum of human disease associations with SLC9A9, we performed a systematic review of the literature. We also review SLC9A9's biochemistry, protein structure, and function, as well as its interacting partners with the goal of identifying mechanisms of disease and druggable targets. We report gaps in the literature regarding the genes function along with consistent trends in disease associations that can be used to further research into treating the respective diseases. We report that SLC9A9 has strong associations with neuropsychiatric diseases and various cancers. Interestingly, we find strong overlap in SLC9A9 disease associations and propose a novel role for SLC9A9 in neuropsychiatric comorbidity. In conclusion, SLC9A9 is a multifunctional protein that, through both its endosome regulatory function and its protein-protein interaction network, has the ability to modulate signaling axes, such as the PI3K pathway, among others.
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Affiliation(s)
- Jameson Patak
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA.,College of Medicine, MD Program, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Stephen V Faraone
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA.,Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Yanli Zhang-James
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York, USA
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22
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Cader MZ, de Almeida Rodrigues RP, West JA, Sewell GW, Md-Ibrahim MN, Reikine S, Sirago G, Unger LW, Iglesias-Romero AB, Ramshorn K, Haag LM, Saveljeva S, Ebel JF, Rosenstiel P, Kaneider NC, Lee JC, Lawley TD, Bradley A, Dougan G, Modis Y, Griffin JL, Kaser A. FAMIN Is a Multifunctional Purine Enzyme Enabling the Purine Nucleotide Cycle. Cell 2020; 180:278-295.e23. [PMID: 31978345 PMCID: PMC6978800 DOI: 10.1016/j.cell.2019.12.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 11/18/2019] [Accepted: 12/12/2019] [Indexed: 12/11/2022]
Abstract
Mutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We developed an unbiased liquid chromatography-mass spectrometry screen for enzymatic activity of this orphan protein. We report that FAMIN phosphorolytically cleaves adenosine into adenine and ribose-1-phosphate. Such activity was considered absent from eukaryotic metabolism. FAMIN and its prokaryotic orthologs additionally have adenosine deaminase, purine nucleoside phosphorylase, and S-methyl-5′-thioadenosine phosphorylase activity, hence, combine activities of the namesake enzymes of central purine metabolism. FAMIN enables in macrophages a purine nucleotide cycle (PNC) between adenosine and inosine monophosphate and adenylosuccinate, which consumes aspartate and releases fumarate in a manner involving fatty acid oxidation and ATP-citrate lyase activity. This macrophage PNC synchronizes mitochondrial activity with glycolysis by balancing electron transfer to mitochondria, thereby supporting glycolytic activity and promoting oxidative phosphorylation and mitochondrial H+ and phosphate recycling. An unbiased LC-MS screen reveals FAMIN as a purine nucleoside enzyme FAMIN combines adenosine phosphorylase with ADA-, PNP-, and MTAP-like activities FAMIN enables a purine nucleotide cycle (PNC) preventing cytoplasmic acidification The FAMIN-dependent PNC balances the glycolysis-mitochondrial redox interface
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Affiliation(s)
- M Zaeem Cader
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Rodrigo Pereira de Almeida Rodrigues
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - James A West
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK; Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, UK
| | - Gavin W Sewell
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Muhammad N Md-Ibrahim
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Stephanie Reikine
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Giuseppe Sirago
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Lukas W Unger
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Ana Belén Iglesias-Romero
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Katharina Ramshorn
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Lea-Maxie Haag
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Svetlana Saveljeva
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Jana-Fabienne Ebel
- Institute of Clinical Molecular Biology, Christian Albrechts University, Campus Kiel, 24105 Kiel, Germany
| | - Philip Rosenstiel
- Institute of Clinical Molecular Biology, Christian Albrechts University, Campus Kiel, 24105 Kiel, Germany
| | - Nicole C Kaneider
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - James C Lee
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | | | - Allan Bradley
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK
| | - Gordon Dougan
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Yorgo Modis
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Julian L Griffin
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, UK
| | - Arthur Kaser
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK; Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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23
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Burn-Induced Apoptosis of Pulmonary Microvascular Endothelial Cell is NHE1 Dependent and Regulated by PI3K-Akt and p38 MAPK Pathways. Shock 2020; 54:819-827. [PMID: 32496418 DOI: 10.1097/shk.0000000000001573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Na/H exchanger 1 (NHE1) is a ubiquitously expressed protein on mammalian plasma membranes and involved in cell apoptosis and tissue injury. Our previous study found that NHE1 inhibition prevents burn-induced acute lung injury (ALI). However, the potential mechanism of NHE1 in burn-induced ALI is still unclear. This study investigated the role of NHE1 in burn-induced apoptosis of human pulmonary microvascular endothelial cells. Based on the western blot analyses, real-time PCR, fluorescence spectroscopy, and apoptosis analysis, we found that burn serum significantly induced NHE1 activation, promoted intracellular Na accumulation, and elevated apoptosis ratio. Inhibition of NHE1 with cariporide reversed burn-induced intracellular Na accumulation and cell apoptosis. Different doses of cariporide also significantly decreased Cai concentrations and calpain activity induced by burn serum. Furthermore, inhibition of PI3K contributed to the increase of NHE1 activation and cell apoptosis, whereas the inhibition of p38 MAPK led to inhibition of NHE1 activation and significant decreases of cell apoptosis. The data demonstrate that NHE1 activation facilitates burn-induced endothelial cell apoptosis, mediated by Ca-dependent pathway. PI3K-Akt and p38 MAPK were found to be upstream regulators of NHE1. This study provides new mechanisms underlying burn-induced ALI.
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24
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Liu CL, Liu X, Wang Y, Deng Z, Liu T, Sukhova GK, Wojtkiewicz GR, Tang R, Zhang JY, Achilefu S, Nahrendorf M, Libby P, Wang X, Shi GP. Reduced Nhe1 (Na +-H + Exchanger-1) Function Protects ApoE-Deficient Mice From Ang II (Angiotensin II)-Induced Abdominal Aortic Aneurysms. Hypertension 2020; 76:87-100. [PMID: 32475310 DOI: 10.1161/hypertensionaha.119.14485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
IgE-mediated activation of Nhe1 (Na+-H+ exchanger-1) induces aortic cell extracellular acidification and promotes cell apoptosis. A pH-sensitive probe pHrodo identified acidic regions at positions of macrophage accumulation, IgE expression, and cell apoptosis in human and mouse abdominal aortic aneurysm (AAA) lesions. Ang II (angiotensin II)-induced AAA in Nhe1-insufficient Apoe-/-Nhe1+/- mice and Apoe-/-Nhe1+/+ littermates tested Nhe1 activity in experimental AAA, because Nhe1-/- mice develop ataxia and epileptic-like seizures and die early. Nhe1 insufficiency reduced AAA incidence and size, lesion macrophage and T-cell accumulation, collagen deposition, elastin fragmentation, cell apoptosis, smooth muscle cell loss, and MMP (matrix metalloproteinase) activity. Nhe1 insufficiency also reduced blood pressure and the plasma apoptosis marker TCTP (translationally controlled tumor protein) but did not affect plasma IgE. While pHrodo localized the acidic regions to macrophage clusters, IgE expression, and cell apoptosis in AAA lesions from Apoe-/-Nhe1+/+ mice, such acidic areas were much smaller in lesions from Apoe-/-Nhe1+/- mice. Nhe1-FcεR1 colocalization in macrophages from AAA lesions support a role of IgE-mediated Nhe1 activation. Gelatin zymography, immunoblot, and real-time polymerase chain reaction analyses demonstrated that Nhe1 insufficiency reduced the MMP activity, cysteinyl cathepsin expression, IgE-induced apoptosis, and NF-κB activation in macrophages and blocked IgE-induced adhesion molecule expression in endothelial cells. A near-infrared fluorescent probe (LS662) together with fluorescence reflectance imaging of intact aortas showed reduced acidity in AAA lesions from Nhe-1-insufficient mice. This study revealed extracellular acidity at regions rich in macrophages, IgE expression, and cell apoptosis in human and mouse AAA lesions and established a direct role of Nhe1 in AAA pathogenesis.
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Affiliation(s)
- Cong-Lin Liu
- From the Department of Cardiology, Institute of Clinical Medicine, the First Affiliated Hospital of Zhengzhou University, China (C.-L.L., Y.W., J.-Y.Z., X.W., G.-P.S.).,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Xin Liu
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Yunzhe Wang
- From the Department of Cardiology, Institute of Clinical Medicine, the First Affiliated Hospital of Zhengzhou University, China (C.-L.L., Y.W., J.-Y.Z., X.W., G.-P.S.).,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Zhiyong Deng
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Tianxiao Liu
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Galina K Sukhova
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Gregory R Wojtkiewicz
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston (G.R.W., M.N.)
| | - Rui Tang
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (R.T., S.A.)
| | - Jin-Ying Zhang
- From the Department of Cardiology, Institute of Clinical Medicine, the First Affiliated Hospital of Zhengzhou University, China (C.-L.L., Y.W., J.-Y.Z., X.W., G.-P.S.)
| | - Samuel Achilefu
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (R.T., S.A.)
| | - Matthias Nahrendorf
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Peter Libby
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
| | - Xiaofang Wang
- From the Department of Cardiology, Institute of Clinical Medicine, the First Affiliated Hospital of Zhengzhou University, China (C.-L.L., Y.W., J.-Y.Z., X.W., G.-P.S.)
| | - Guo-Ping Shi
- From the Department of Cardiology, Institute of Clinical Medicine, the First Affiliated Hospital of Zhengzhou University, China (C.-L.L., Y.W., J.-Y.Z., X.W., G.-P.S.).,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (C.-L.L., X.L., Y.W., Z.D., T.L., G.K.S., P.L., G.-P.S.)
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25
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Sin WC, Tam N, Moniz D, Lee C, Church J. Na/H exchanger NHE1 acts upstream of rho GTPases to promote neurite outgrowth. J Cell Commun Signal 2020; 14:325-333. [PMID: 32144636 DOI: 10.1007/s12079-020-00556-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/28/2020] [Indexed: 02/05/2023] Open
Abstract
Na+/H+ exchanger NHE1, a major determinant of intracellular pH (pHi) in mammalian central neurons, promotes neurite outgrowth under both basal and netrin-1-stimulated conditions. The small GTP binding proteins and their effectors have a dominant role in netrin-1-stimulated neurite outgrowth. Since NHE1 has been shown previously to work downstream of the Rho GTPases-mediated polarized membrane protrusion in non-neuronal cells, we examined whether NHE1 has a similar relationship with Cdc42, Rac1 and RhoA in neuronal morphogenesis. Interestingly, our results suggest the possibility that NHE1 acting upstream of Rho GTPases to promote neurite outgrowth induced by netrin-1. First, we found that netrin-1-induced increases in the activities of Rho GTPases using FRET (Forster Resonance Energy Transfer) analyses in individual growth cones; furthermore, their increased activities were abolished by cariporide, a specific NHE1 inhibitor. Second, NHE1 inhibition had no effect on neurite retraction induced by L-α-Lysophosphatidic acid (LPA), a potent RhoA activator. The regulation of Rho GTPases by NHE1 was further evidenced by reduced Rac1, Cdc42 and RhoA activities in NHE1-null neurons. Taken together, our findings suggest that NHE1-dependent neuronal morphogenesis involves the activation of Rho-family of small GTPases.
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Affiliation(s)
- Wun Chey Sin
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada.
| | - Nicola Tam
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - David Moniz
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Connie Lee
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - John Church
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
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26
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Molecular mechanisms associated with acidification and alkalization along the larval midgut of Musca domestica. Comp Biochem Physiol A Mol Integr Physiol 2019; 237:110535. [DOI: 10.1016/j.cbpa.2019.110535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 01/07/2023]
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27
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Albatany M, Ostapchenko VG, Meakin S, Bartha R. Brain tumor acidification using drugs simultaneously targeting multiple pH regulatory mechanisms. J Neurooncol 2019; 144:453-462. [PMID: 31392597 DOI: 10.1007/s11060-019-03251-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/22/2019] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Non-invasively distinguishing aggressive from non-aggressive brain tumors is an important clinical challenge. Intracellular pH (pHi) regulation is essential for normal cell function and is normally maintained within a narrow range. Cancer cells are characterized by a reversed intracellular to extracellular pH gradient, compared to healthy cells, that is maintained by several distinct mechanisms. Previous studies have demonstrated acute pH modulation in glioblastoma detectable by chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) after blocking individual pH regulatory mechanisms. The purpose of the current study was to simultaneously block five pH regulatory mechanisms while also providing glucose as an energy substrate. We hypothesized that this approach would increase the acute pH modulation effect allowing the identification of aggressive cancer. METHODS Using a 9.4 T MRI scanner, CEST spectra were acquired sensitive to pHi using amine/amide concentration independent detection (AACID). Twelve mice were scanned approximately 11 ± 1 days after implanting 105 U87 human glioblastoma multiforme cells in the brain, before and after intraperitoneal injection of a combination of five drugs (quercetin, cariporide, dichloroacetate, acetazolamide, and pantoprazole) with and without glucose. RESULTS Two hours after combination drug injection there was a significant 0.1 ± 0.03 increase in tumor AACID value corresponding to a 0.4 decrease in pHi. After injecting the drug combination with glucose the AACID value increased by 0.18 ± 0.03 corresponding to a 0.72 decrease in pHi. AACID values were also slightly increased in contralateral tissue. CONCLUSIONS The combined drug treatment with glucose produced a large acute CEST MRI contrast indicating tumor acidification, which could be used to help localize brain cancer and monitor tumor response to chemotherapy.
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Affiliation(s)
- Mohammed Albatany
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, ON, N65B7, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, ON, N65B7, Canada
| | - Valeriy G Ostapchenko
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, ON, N65B7, Canada
| | - Susan Meakin
- Department of Biochemistry, The University of Western Ontario, London, ON, N65B7, Canada
| | - Robert Bartha
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, ON, N65B7, Canada.
- Department of Medical Biophysics, The University of Western Ontario, London, ON, N65B7, Canada.
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28
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Ramírez MA, Beltrán AR, Araya JE, Cornejo M, Toledo F, Fuentes G, Sobrevia L. Involvement of Intracellular pH in Vascular Insulin Resistance. Curr Vasc Pharmacol 2019; 17:440-446. [DOI: 10.2174/1570161116666180911104012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/02/2018] [Accepted: 08/04/2018] [Indexed: 12/25/2022]
Abstract
The maintenance of the pH homeostasis is maintained by several mechanisms including the
efflux of protons (H+) via membrane transporters expressed in almost all mammalian cells. Along these
membrane transporters the sodium/H+ exchangers (NHEs), mainly NHE isoform 1 (NHE1), plays a key
role in this phenomenon. NHE1 is under modulation by several environmental conditions (e.g. hyperglycaemia,
protein kinase C activity) as well as hormones, including insulin. NHE1 activation causes
intracellular alkalization in human endothelial cells leading to activation of the endothelial Nitric Oxide
Synthase (eNOS) to generate NO. Intracellular alkalization is a phenomenon that also results in upregulation
of the glucose transporter GLUT4 in cells that are responsive to insulin. A reduction in the removal
of the extracellular D-glucose is seen in states of insulin resistance, such as in diabetes mellitus
and obesity. Since insulin is a potent activator of eNOS in human endothelium, therefore causing vasodilation,
and its vascular effect is reduced in insulin resistance it is likely that a defective signal to activate
NHE1 in insulin target cells is expected. This phenomenon results in lower redistribution and activation
of GLUT4 leading to reduced uptake of D-glucose and hyperglycaemia. The general concept of a
role for NHE1, and perhaps other NHEs isoforms, in insulin resistance in the human vasculature is proposed.
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Affiliation(s)
- Marco A. Ramírez
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8330024, Chile
| | - Ana R. Beltrán
- Laboratorio de Fisiologia Celular, Departamento Biomedico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Jorge E. Araya
- Laboratorio de Fisiologia Celular, Departamento Biomedico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Marcelo Cornejo
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8330024, Chile
| | - Fernando Toledo
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8330024, Chile
| | - Gonzalo Fuentes
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8330024, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8330024, Chile
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29
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Liu Y, Wen H, Qi X, Zhang X, Zhang K, Fan H, Tian Y, Hu Y, Li Y. Genome-wide identification of the Na+/H+ exchanger gene family in Lateolabrax maculatus and its involvement in salinity regulation. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2019; 29:286-298. [DOI: 10.1016/j.cbd.2019.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 01/21/2023]
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30
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Zhu ML, Wang G, Wang H, Guo YM, Song P, Xu J, Li P, Wang S, Yang L. Amorphous nano-selenium quantum dots improve endothelial dysfunction in rats and prevent atherosclerosis in mice through Na +/H + exchanger 1 inhibition. Vascul Pharmacol 2019; 115:26-32. [PMID: 30695730 DOI: 10.1016/j.vph.2019.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/08/2019] [Accepted: 01/25/2019] [Indexed: 12/27/2022]
Abstract
AIM Selenium, a trace element involved in important enzymatic activities inside the body, has protective effects against cardiovascular diseases including atherosclerosis. The safe dose of selenium in the organism is very narrow, limiting the supplementation of selenium in diet. The aim of this study is to explore whether selenium quantum dots (SeQDs) prevent atherosclerosis and to investigate the potential mechanisms. METHODS An amorphous form of SeQDs (A-SeQDs) and a crystalline form of SeQDs (C-SeQDs) were prepared through self-redox decomposition of selenosulfate precursor. Endothelial dysfunction was induced by balloon injury plus high fat diet (HFD) in rats. Atherosclerotic model was established by feeding Apoe-/- mice with HFD. RESULTS Administrations of A-SeQDs but not C-SeQDs dramatically improved endothelium-dependent relaxation, and accelerated would healing in primary endothelial cells isolated from rats, which was comprised by co-treatment of LiCl. Lentivirus-mediated knockdown of Na+/H+ exchanger 1 (NHE1) abolished LiCl-induced endothelial dysfunction in rats. In cultured endothelial cells, A-SeQDs, as well as cariporide, inhibited NHE1 activities, decreased intracellular pH value and Ca2+ concentration, and reduced calpain activity increased by ox-LDL. These protective effects of A-SeQDs were reversed by LiCl treatment in endothelial cells. In Apoe-/- mice feeding with HFD, A-SeQDs prevented endothelial dysfunction and reduced the size of atherosclerotic plaque in aortic arteries. Further, lentivirus-mediated NHE1 gene overexpression abolished the protective effects of A-SeQDs against endothelial dysfunction and atherosclerosis in Apoe-/- mice. CONCLUSION A-SeQDs prevents endothelial dysfunction and the growth of atherosclerotic plaque through NHE1 inhibition and subsequent inactivation of Ca2+/calpain signaling. Clinically, the administration of A-SeQDs is an effective approach to treat atherosclerosis.
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Affiliation(s)
- Mo-Li Zhu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China; School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China
| | - Ge Wang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China; School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China
| | - He Wang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China
| | - Yu-Ming Guo
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China
| | - Ping Song
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China
| | - Jian Xu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China
| | - Peng Li
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.
| | - Shuangxi Wang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.
| | - Lin Yang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China.
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31
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Poon AC, Inkol JM, Luu AK, Mutsaers AJ. Effects of the potassium-sparing diuretic amiloride on chemotherapy response in canine osteosarcoma cells. J Vet Intern Med 2018; 33:800-811. [PMID: 30556178 PMCID: PMC6430882 DOI: 10.1111/jvim.15382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/14/2018] [Indexed: 02/07/2023] Open
Abstract
Background Osteosarcoma (OSA) is a common bone tumor of mesenchymal origin in dogs. Chemotherapy delays metastasis, yet most dogs die of this disease within 1 year of diagnosis. The high metabolic demand of cancer cells promotes proton pump upregulation, leading to acidification of the tumor microenvironment and chemoresistance. The potassium‐sparing diuretic amiloride is among a class of proton pump inhibitors prescribed for refractory heart failure treatment in dogs. Objective We hypothesized that amiloride treatment improves chemotherapy response by reducing acidification in canine OSA cells. Our objective was to assess the in vitro effects of amiloride on cell viability, apoptosis, and metabolism. Methods In vitro study. Assessments of cell viability and apoptosis were performed after single agent or combination treatment, along with calculations of pharmacological synergism using the combination index. Protein signaling during apoptosis was evaluated by Western blotting. Metabolic profiling was performed using a Seahorse bioanalyzer. Results Amiloride strongly synergized with doxorubicin in combination treatment and exhibited additive or antagonistic effects with carboplatin in canine OSA cells. Combination treatment with doxorubicin significantly upregulated p53‐mitochondrial signaling to activate apoptosis and downregulate Akt phosphorylation. Amiloride‐treated cells further exhibited metabolic switching with reductions in glycolytic capacity and maximal respiration. Conclusion and Clinical Importance Amiloride synergized with doxorubicin to potentiate apoptosis in canine OSA cells. These results justify further investigation into repurposing of amiloride as an oncology drug for the treatment of OSA in dogs.
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Affiliation(s)
- Andrew C Poon
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Jordon M Inkol
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Anita K Luu
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Anthony J Mutsaers
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.,Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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32
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Soto E, Ortega-Ramírez A, Vega R. Protons as Messengers of Intercellular Communication in the Nervous System. Front Cell Neurosci 2018; 12:342. [PMID: 30364044 PMCID: PMC6191491 DOI: 10.3389/fncel.2018.00342] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/14/2018] [Indexed: 12/18/2022] Open
Abstract
In this review, evidence demonstrating that protons (H+) constitute a complex, regulated intercellular signaling mechanisms are presented. Given that pH is a strictly regulated variable in multicellular organisms, localized extracellular pH changes may constitute significant signals of cellular processes that occur in a cell or a group of cells. Several studies have demonstrated that the low pH of synaptic vesicles implies that neurotransmitter release is always accompanied by the co-release of H+ into the synaptic cleft, leading to transient extracellular pH shifts. Also, evidence has accumulated indicating that extracellular H+ concentration regulation is complex and implies a source of protons in a network of transporters, ion exchangers, and buffer capacity of the media that may finally establish the extracellular proton concentration. The activation of membrane transporters, increased production of CO2 and of metabolites, such as lactate, produce significant extracellular pH shifts in nano- and micro-domains in the central nervous system (CNS), constituting a reliable signal for intercellular communication. The acid sensing ion channels (ASIC) function as specific signal sensors of proton signaling mechanism, detecting subtle variations of extracellular H+ in a range varying from pH 5 to 8. The main question in relation to this signaling system is whether it is only synaptically restricted, or a volume modulator of neuron excitability. This signaling system may have evolved from a metabolic activity detection mechanism to a highly localized extracellular proton dependent communication mechanism. In this study, evidence showing the mechanisms of regulation of extracellular pH shifts and of the ASICs and its function in modulating the excitability in various systems is reviewed, including data and its role in synaptic neurotransmission, volume transmission and even segregated neurotransmission, leading to a reliable extracellular signaling mechanism.
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Affiliation(s)
- Enrique Soto
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | | | - Rosario Vega
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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33
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Sun DI, Tasca A, Haas M, Baltazar G, Harland RM, Finkbeiner WE, Walentek P. Na+/H+ Exchangers Are Required for the Development and Function of Vertebrate Mucociliary Epithelia. Cells Tissues Organs 2018; 205:279-292. [PMID: 30300884 DOI: 10.1159/000492973] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/19/2018] [Indexed: 11/19/2022] Open
Abstract
Na+/H+ exchangers (NHEs) represent a highly conserved family of ion transporters that regulate pH homeostasis. NHEs as well as other proton transporters were previously linked to the regulation of the Wnt signaling pathway, cell polarity signaling, and mucociliary function. Furthermore, mutations in the gene SLC9A3 (encoding NHE3) were detected as additional risk factors for airway infections in cystic fibrosis patients. Here, we used the Xenopus embryonic mucociliary epidermis as well as human airway epithelial cells (HAECs) as models to investigate the functional roles of NHEs in mucociliary development and regeneration. In Xenopus embryos, NHEs 1-3 were expressed during epidermal development, and loss of NHE function impaired mucociliary clearance in tadpoles. Clearance defects were caused by reduced cilia formation, disrupted alignment of basal bodies in multiciliated cells (MCCs), and dysregulated mucociliary gene expression. These data also suggested that NHEs may contribute to the activation of Wnt signaling in mucociliary epithelia. In HAECs, pharmacological inhibition of NHE function also caused defective ciliation and regeneration in airway MCCs. Collectively, our data revealed a requirement for NHEs in vertebrate mucociliary epithelia and linked NHE activity to cilia formation and function in differentiating MCCs. Our results provide an entry point for the understanding of the contribution of NHEs to signaling, development, and pathogenesis in the human respiratory tract.
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Affiliation(s)
- Dingyuan I Sun
- Genetics, Genomics and Development Division, Molecular and Cell Biology Department, University of California, Berkeley, California, USA.,Department of Pathology, University of California, San Francisco, California, USA
| | - Alexia Tasca
- Renal Division, Department of Medicine, University Freiburg Medical Center and ZBSA - Center for Systems Biological Analysis, Freiburg, Germany
| | - Maximilian Haas
- Renal Division, Department of Medicine, University Freiburg Medical Center and ZBSA - Center for Systems Biological Analysis, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Grober Baltazar
- Genetics, Genomics and Development Division, Molecular and Cell Biology Department, University of California, Berkeley, California, USA.,Children's Medical Research Institute, Westmead, New South Wales, Australia
| | - Richard M Harland
- Genetics, Genomics and Development Division, Molecular and Cell Biology Department, University of California, Berkeley, California, USA
| | - Walter E Finkbeiner
- Department of Pathology, University of California, San Francisco, California, USA
| | - Peter Walentek
- Genetics, Genomics and Development Division, Molecular and Cell Biology Department, University of California, Berkeley, California, .,Renal Division, Department of Medicine, University Freiburg Medical Center and ZBSA - Center for Systems Biological Analysis, Freiburg, .,Spemann Graduate School of Biology and Medicine, Albert Ludwigs University Freiburg, Freiburg,
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34
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Wong KY, McKay R, Liu Y, Towle K, Elloumi Y, Li X, Quan S, Dutta D, Sykes BD, Fliegel L. Diverse residues of intracellular loop 5 of the Na +/H + exchanger modulate proton sensing, expression, activity and targeting. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:191-200. [PMID: 30071192 DOI: 10.1016/j.bbamem.2018.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 10/28/2022]
Abstract
The mammalian Na+/H+ exchanger isoform 1 (NHE1) is an integral membrane protein that regulates intracellular pH (pHi) by removing a single intracellular proton in exchange for one extracellular sodium ion. It is involved in cardiac hypertrophy and ischemia reperfusion damage to the heart and elevation of its activity is a trigger for breast cancer metastasis. NHE1 has an extensive 500 amino acid N-terminal membrane domain that mediates transport and consists of 12 transmembrane segments connected by intracellular and extracellular loops. Intracellular loops are hypothesized to modulate the sensitivity to pHi. In this study, we characterized the structure and function of intracellular loop 5 (IL5), specifically amino acids 431-443. Mutation of eleven residues to alanine caused partial or nearly complete inhibition of transport; notably, mutation of residues L432, T433, I436, N437, R440 and K443 demonstrated these residues had critical roles in NHE1 function independent of effects on targeting or expression. The nuclear magnetic resonance (NMR) solution spectra of the IL5 peptide in a membrane mimetic sodium dodecyl sulfate solution revealed that IL5 has a stable three-dimensional structure with substantial alpha helical character. NMR chemical shifts indicated that K438 was in close proximity with W434. Overall, our results show that IL5 is a critical, intracellular loop with a propensity to form an alpha helix, and many residues of this intracellular loop are critical to proton sensing and ion transport.
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Affiliation(s)
- Ka Yee Wong
- Dept of Biochemistry, University of Alberta, Canada
| | - Ryan McKay
- Dept of Chemistry, University of Alberta, Canada.
| | | | | | | | - Xiuju Li
- Dept of Biochemistry, University of Alberta, Canada
| | - Sicheng Quan
- Dept of Biochemistry, University of Alberta, Canada
| | | | | | - Larry Fliegel
- Dept of Biochemistry, University of Alberta, Canada.
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35
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Sun S, Li H, Chen J, Qian Q. Lactic Acid: No Longer an Inert and End-Product of Glycolysis. Physiology (Bethesda) 2018; 32:453-463. [PMID: 29021365 DOI: 10.1152/physiol.00016.2017] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/07/2017] [Accepted: 09/07/2017] [Indexed: 12/21/2022] Open
Abstract
For decades, lactic acid has been considered a dead-end product of glycolysis. Research in the last 20+ years has shown otherwise. Through its transporters (MCTs) and receptor (GPR81), lactic acid plays a key role in multiple cellular processes, including energy regulation, immune tolerance, memory formation, wound healing, ischemic tissue injury, and cancer growth and metastasis. We summarize key findings of lactic acid signaling, functions, and many remaining questions.
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Affiliation(s)
- Shiren Sun
- Department of Nephrology, Xijing Hospital, the Fourth Military Medical University, Xian, China
| | - Heng Li
- Kidney Disease Center, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; and
| | - Jianghua Chen
- Kidney Disease Center, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; and
| | - Qi Qian
- Department of Medicine, Division of Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, Minnesota
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36
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Transepithelial Fluid and Salt Re-Absorption Regulated by cGK2 Signals. Int J Mol Sci 2018; 19:ijms19030881. [PMID: 29547542 PMCID: PMC5877742 DOI: 10.3390/ijms19030881] [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: 01/22/2018] [Revised: 02/12/2018] [Accepted: 03/14/2018] [Indexed: 12/23/2022] Open
Abstract
Transepithelial fluid and salt re-absorption in epithelial tissues play an important role in fluid and salt homeostasis. In absorptive epithelium, fluid and salt flux is controlled by machinery mainly composed of epithelial sodium channels (ENaC), cystic fibrosis transmembrane conductance regulator (CFTR), Na⁺/H⁺ exchanger (NHE), aquaporin, and sodium potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). Dysregulation of fluid and salt transport across epithelium contributes to the pathogenesis of many diseases, such as pulmonary edema and cystic fibrosis. Intracellular and extracellular signals, i.e., hormones and protein kinases, regulate fluid and salt turnover and resolution. Increasing evidence demonstrates that transepithelial fluid transport is regulated by cyclic guanosine monophosphate-dependent protein kinase (cGK) signals. cGK2 was originally identified and cloned from intestinal specimens, the presence of which has also been confirmed in the kidney and the lung. cGK2 regulates fluid and salt through ENaC, CFTR and NHE. Deficient cGK2 regulation of transepithelial ion transport was seen in acute lung injury, and cGK2 could be a novel druggable target to restore edematous disorder in epithelial tissues.
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37
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Muzzachi S, Guerra L, Martino NA, Favia M, Punzi G, Silvestre F, Guaricci AC, Roscino MT, Pierri CL, Dell'Aquila ME, Casavola V, Lacalandra GM, Ciani E. Effect of cariporide on ram sperm pH regulation and motility: possible role of NHE1. Reproduction 2018; 155:433-445. [PMID: 29491124 DOI: 10.1530/rep-17-0456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 02/27/2018] [Indexed: 01/05/2023]
Abstract
Sperm motility, a feature essential for in vivo fertilization, is influenced by intracellular pH (pHi) homeostasis. Several mechanisms are involved in pHi regulation, among which sodium-hydrogen exchangers (NHEs), a family of integral transmembrane proteins that catalyze the exchange of Na+ for H+ across lipid bilayers. A preliminary characterization of NHE activity and kinetic parameters, followed by analysis of the expression and localization of the protein in ram spermatozoa was performed. NHE activity showed an apparent Km for external Na+ of 17.61 mM. Immunoblotting revealed a molecular mass of 85 kDa. Immunolocalization pattern showed some species-specific aspects, such as positive labeling at the equatorial region of the sperm head. Cariporide, a selective NHE1 inhibitor, significantly reduced pHi recovery (85%). Similarly, exposure to cariporide significantly inhibited different motility parameters, including those related to sperm capacitation. In vitro fertilization (IVF) was not affected by cariporide, possibly due to the non-dramatic, although significant, drop in motility and velocity parameters or due to prolonged exposure during IVF, which may have caused progressive loss of its inhibitory effect. In conclusion, this is the first study documenting, in a large animal model (sheep) of well-known translational relevance, a direct functional role of NHE on sperm pHi and motility. The postulated specificity of cariporide toward isoform 1 of the Na+/H+ exchanger seems to suggest that NHE1 may contribute to the observed effects on sperm cell functionality.
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Affiliation(s)
- Stefania Muzzachi
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Lorenzo Guerra
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Nicola Antonio Martino
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy.,Istituto Zooprofilattico Sperimentale della Puglia e della BasilicataFoggia, Italy
| | - Maria Favia
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Giuseppe Punzi
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Fabio Silvestre
- Section of Veterinary Clinics and Animal ProductionsDepartment of Emergency and Organ Transplantation, University of Bari 'Aldo Moro', Valenzano, Bari, Italy
| | - Antonio Ciro Guaricci
- Section of Veterinary Clinics and Animal ProductionsDepartment of Emergency and Organ Transplantation, University of Bari 'Aldo Moro', Valenzano, Bari, Italy
| | - Maria Teresa Roscino
- Section of Veterinary Clinics and Animal ProductionsDepartment of Emergency and Organ Transplantation, University of Bari 'Aldo Moro', Valenzano, Bari, Italy
| | - Ciro Leonardo Pierri
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Maria Elena Dell'Aquila
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Valeria Casavola
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
| | - Giovanni Michele Lacalandra
- Section of Veterinary Clinics and Animal ProductionsDepartment of Emergency and Organ Transplantation, University of Bari 'Aldo Moro', Valenzano, Bari, Italy
| | - Elena Ciani
- Department of BiosciencesBiotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Bari, Italy
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38
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Na+/H+ exchanger 1 has tumor suppressive activity and prognostic value in esophageal squamous cell carcinoma. Oncotarget 2018; 8:2209-2223. [PMID: 27902974 PMCID: PMC5356793 DOI: 10.18632/oncotarget.13645] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 10/21/2016] [Indexed: 12/30/2022] Open
Abstract
Na+/H+ exchanger 1 (NHE1) is a plasma membrane transporter that controls intracellular pH and regulates apoptosis and invasion in various cancer cells. However, the function of NHE1 in esophageal squamous cell carcinoma (ESCC) cells and the relationship between the expression of NHE1 and prognosis of ESCC remain unclear. We found that the knockdown of NHE1 in ESCC cells inhibited apoptosis and promoted cell proliferation, migration, and invasion and showed increases in Snail, β-catenin, and activation of PI3K-AKT signaling, which was consistent with the results obtained from microarrays. Microarrays results suggested that the knockdown of NHE1 suppressed Notch signaling pathway. An immunohistochemical investigation of 61 primary ESCC samples revealed that NHE1 was expressed at higher levels in well-differentiated tumors. The 5-year survival rate was poorer in the NHE1 low group (57.0%) than in the NHE1 high group (82.8%). Multivariate analyses revealed that the weak expression of NHE1 was associated with shorter postoperative survival (hazard ratio 3.570, 95% CI 1.291-11.484, p = 0.0135).We herein demonstrated that the suppression of NHE1 in ESCC may enhance malignant potential by mediating PI3K-AKT signaling and EMT via Notch signaling, and may be related to a poor prognosis in patients with ESCC.
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39
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Hiong KC, Cao-Pham AH, Choo CYL, Boo MV, Wong WP, Chew SF, Ip YK. Light-dependent expression of a Na +/H + exchanger 3-like transporter in the ctenidium of the giant clam, Tridacna squamosa, can be related to increased H + excretion during light-enhanced calcification. Physiol Rep 2018; 5:5/8/e13209. [PMID: 28438983 PMCID: PMC5408280 DOI: 10.14814/phy2.13209] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 02/22/2017] [Indexed: 12/03/2022] Open
Abstract
Na+/H+ exchangers (NHEs) regulate intracellular pH and ionic balance by mediating H+ efflux in exchange for Na+ uptake in a 1:1 stoichiometry. This study aimed to obtain from the ctenidium of the giant clam Tridacna squamosa (TS) the complete cDNA sequence of a NHE3‐like transporter (TSNHE3), and to determine the effect of light exposure on its mRNA expression level and protein abundance therein. The coding sequence of TSNHE3 comprised 2886 bp, encoding 961 amino acids with an estimated molecular mass of 105.7 kDa. Immunofluorescence microscopy revealed that TSNHE3 was localized to the apical membrane of epithelial cells of the ctenidial filaments and the tertiary water channels. Particularly, the apical immunofluorescence of the ctenidial filaments was consistently stronger in the ctenidium of clams exposed to 12 h of light than those of the control kept in darkness. Indeed, light induced significant increases in the transcript level and protein abundance of TSNHE3/TSNHE3 in the ctenidium, indicating that the transcription and translation of TSNHE3/TSNHE3 were light‐dependent. As light‐enhanced calcification generates H+, the increased expression of TSNHE3/TSNHE3 in the ctenidium could be a response to augment H+ excretion in pursuance of whole‐body acid‐base balance during light exposure. These results signify that shell formation in giant clams requires the collaboration between the ctenidium, which is a respiratory and iono‐regulatory organ, and the inner mantle, which is directly involved in the calcification process, and provide new insights into the mechanisms of light‐enhanced calcification in giant clams.
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Affiliation(s)
- Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
| | - Anh H Cao-Pham
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
| | - Celine Y L Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Nanyang Walk, Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore .,The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore
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40
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Idili A, Ricci F. Design and Characterization of pH-Triggered DNA Nanoswitches and Nanodevices Based on DNA Triplex Structures. Methods Mol Biol 2018; 1811:79-100. [PMID: 29926447 DOI: 10.1007/978-1-4939-8582-1_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Triplex DNA is becoming a very useful domain to design pH-triggered DNA nanoswitches and nanodevices. The high versatility and programmability of triplex DNA interactions allows the integration of pH-controllable modules into DNA-based reactions and self-assembly processes. Here, we describe the procedure to characterize DNA-based triplex nanoswitches and more in general pH-triggered structure-switching mechanisms. Procedures to characterize pH-triggered DNA nanodevices will be useful for many applications in the field of biosensing, drug delivery systems and smart nanomaterials.
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Affiliation(s)
- Andrea Idili
- Department of Chemistry, University of Rome Tor Vergata, Rome, Italy
| | - Francesco Ricci
- Department of Chemistry, University of Rome Tor Vergata, Rome, Italy.
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41
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Residues 28 to 39 of the Extracellular Loop 1 of Chicken Na +/H + Exchanger Type I Mediate Cell Binding and Entry of Subgroup J Avian Leukosis Virus. J Virol 2017; 92:JVI.01627-17. [PMID: 29070685 DOI: 10.1128/jvi.01627-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/17/2017] [Indexed: 12/14/2022] Open
Abstract
Chicken Na+/H+ exchanger type I (chNHE1), a multispan transmembrane protein, is a cellular receptor of the subgroup J avian leukosis virus (ALV-J). To identify the functional determinants of chNHE1 responsible for the ALV-J receptor activity, a series of chimeric receptors was created by exchanging the extracellular loops (ECL) of human NHE1 (huNHE1) and chNHE1 and by ECL replacement with a hemagglutinin (HA) tag. These chimeric receptors then were used in binding and entry assays to map the minimal ALV-J gp85-binding domain of chNHE1. We show that ECL1 of chNHE1 (chECL1) is the critical functional ECL that interacts directly with ALV-J gp85; ECL3 is also involved in ALV-J gp85 binding. Amino acid residues 28 to 39 of the N-terminal membrane-proximal region of chECL1 constitute the minimal domain required for chNHE1 binding of ALV-J gp85. These residues are sufficient to mediate viral entry into ALV-J nonpermissive cells. Point mutation analysis revealed that A30, V33, W38, and E39 of chECL1 are the key residues mediating the binding between chNHE1 and ALV-J gp85. Further, the replacement of residues 28 to 39 of huNHE1 with the corresponding chNHE1 residues converted the nonfunctional ALV-J receptor huNHE1 to a functional one. Importantly, soluble chECL1 and huECL1 harboring chNHE1 residues 28 to 39 both could effectively block ALV-J infection. Collectively, our findings indicate that residues 28 to 39 of chNHE1 constitute a domain that is critical for receptor function and mediate ALV-J entry.IMPORTANCE chNHE1 is a cellular receptor of ALV-J, a retrovirus that causes infections in chickens and serious economic losses in the poultry industry. Until now, the domains determining the chNHE1 receptor function remained unknown. We demonstrate that chECL1 is critical for receptor function, with residues 28 to 39 constituting the minimal functional domain responsible for chNHE1 binding of ALV-J gp85 and efficiently mediating ALV-J cell entry. These residues are located in the membrane-proximal region of the N terminus of chECL1, suggesting that the binding site of ALV-J gp85 on chNHE1 is probably located on the apex of the molecule; the receptor-binding mode might be different from that of retroviruses. We also found that soluble chECL1, as well as huECL1 harboring chNHE1 residues 28 to 39, effectively blocked ALV-J infection. These findings contribute to a better understanding of the ALV-J infection mechanism and also provide new insights into the control strategies for ALV-J infection.
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Chen X, Wang X, Tang L, Wang J, Shen C, Liu J, Lu S, Zhang H, Kuang Y, Fei J, Wang Z. Nhe5 deficiency enhances learning and memory via upregulating Bdnf/TrkB signaling in mice. Am J Med Genet B Neuropsychiatr Genet 2017; 174:828-838. [PMID: 28981195 DOI: 10.1002/ajmg.b.32600] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/10/2017] [Accepted: 09/05/2017] [Indexed: 11/11/2022]
Abstract
Nhe5, a Na+ /H+ exchanger, is predominantly expressed in brain tissue and is proposed to act as a negative regulator of dendritic spine growth. Up to now, its physiological function in vivo remains unclear. Here we show that Nhe5-deficient mice exhibit markedly enhanced learning and memory in Morris water maze, novel object recognition, and passive avoidance task. Meanwhile, the pre- and post-synaptic components, synaptophysin (Syn) and post-synaptic density 95 (PSD95) expression levels were found increased in hippocampal regions lacking of Nhe5, suggesting a possible alterations in neuronal synaptic structure and function in Nhe5-/- mice. Further study reveals that Nhe5 deficiency leads to higher Bdnf expression levels, followed by increased phosphorylated TrkB and PLCγ levels, indicating that Bdnf/TrkB signaling is activated due to Nhe5 deficiency. Moreover, the corresponding brain regions of Nhe5-/- mice display elevated ERK/CaMKII/CREB phosphorylation levels. Taken together, these findings uncover a novel physiological function of Nhe5 in regulating learning and memory, further implying Nhe5 as a potential therapeutic target for improving cognition.
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Affiliation(s)
- Xuejiao Chen
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.,Shanghai Research Center for Model Organisms, Shanghai, China
| | - Xiyi Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.,Shanghai Research Center for Model Organisms, Shanghai, China
| | - Lingyun Tang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China
| | - Jinjin Wang
- Shanghai Research Center for Model Organisms, Shanghai, China
| | - Chunling Shen
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.,Shanghai Research Center for Model Organisms, Shanghai, China
| | - Jianbing Liu
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.,Shanghai Research Center for Model Organisms, Shanghai, China
| | - Shunyuan Lu
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China
| | - Hongxin Zhang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China
| | - Ying Kuang
- Shanghai Research Center for Model Organisms, Shanghai, China
| | - Jian Fei
- Shanghai Research Center for Model Organisms, Shanghai, China
| | - Zhugang Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.,Shanghai Research Center for Model Organisms, Shanghai, China.,Department of Medical Genetics, E-Institutes of Shanghai Universities, SJTUSM, Shanghai, China
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Chen XL, Zhang B, Chng YR, Ong JLY, Chew SF, Wong WP, Lam SH, Ip YK. Na +/H + Exchanger 3 Is Expressed in Two Distinct Types of Ionocyte, and Probably Augments Ammonia Excretion in One of Them, in the Gills of the Climbing Perch Exposed to Seawater. Front Physiol 2017; 8:880. [PMID: 29209224 PMCID: PMC5701670 DOI: 10.3389/fphys.2017.00880] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/18/2017] [Indexed: 01/22/2023] Open
Abstract
The freshwater climbing perch, Anabas testudineus, is an euryhaline teleost and an obligate air-breather with the ability to actively excrete ammonia. Members of the Na+/H+ exchanger (NHE) family help maintain intracellular pH homeostasis and ionic balance through the electroneutral exchange of Na+ and H+. This study aimed to obtain, from the gills of A. testudineus, the full cDNA coding sequence of nhe3, and to determine the effects of exposure to seawater or 100 mmol l-1 of NH4Cl in fresh water on its mRNA and protein expression levels. Efforts were also made to elucidate the type of ionocyte that Nhe3 was associated with in the branchial epithelium of A. testudineus. The transcript level and protein abundance of nhe3/Nhe3 were very low in the gills of freshwater A. testudineus, but they increased significantly in the gills of fish acclimated to seawater. In the gills of fish exposed to seawater, Nhe3 was expressed in two distinct types of seawater-inducible Na+/K+-ATPase (Nka)-immunoreactive ionocytes. In Nkaα1b-immunoreactive ionocytes, Nhe3 had an apical localization. As these ionocytes also expressed apical Rhcg1 and basolateral Rhcg2, which are known to transport ammonia, they probably participated in proton-facilitated ammonia excretion in A. testudineus during seawater acclimation. In Nkaα1c-immunoreactive ionocytes, Nhe3 was atypically expressed in the basolateral membrane, and its physiological function is uncertain. For A. testudineus exposed to NH4Cl in fresh water, the transcript and protein expression levels of nhe3/Nhe3 remained low. In conclusion, the branchial Nhe3 of A. testudineus plays a greater physiological role in passive ammonia transport and acid-base balance during seawater acclimation than in active ammonia excretion during environmental ammonia exposure.
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Affiliation(s)
- Xiu L. Chen
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Biyan Zhang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - You R. Chng
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Siew H. Lam
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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The 150 most important questions in cancer research and clinical oncology series: questions 57-66 : Edited by Chinese Journal of Cancer. CHINESE JOURNAL OF CANCER 2017; 36:79. [PMID: 28974261 PMCID: PMC5627450 DOI: 10.1186/s40880-017-0249-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 09/19/2017] [Indexed: 12/15/2022]
Abstract
Since the beginning of 2017, Chinese Journal of Cancer has published a series of important questions in cancer research and clinical oncology, which sparkle diverse thoughts, interesting communications, and potential collaborations among researchers all over the world. In this article, 10 more questions are presented as followed. Question 57. What are the major stresses that drive the formation, progression, and metastasis of a cancer? Question 58. What is the mechanism responsible for altering an acidic intracellular pH and a basic extracellular pH in normal tissue cells to a basic intracellular pH and an acidic extracellular pH in cancer cells, a fundamental and yet largely ignored phenomenon? Question 59. Where are the tumor-associated plasma microRNAs from in cancer patients? Question 60. Can we identify mechanisms employed by tumor subpopulations to evade standard therapies and seed relapse/metastatic tumors before treatment? Question 61. Why are mutation rates in epidermal growth factor receptor (EGFR) and erb-b2 receptor tyrosine kinase 2 (ERBB2) higher in lung cancer from never smokers than that from smokers? Question 62. Does tumor vasculogenic mimicry contribute to the resistance against antiangiogenic therapy in renal cancer? Question 63. What molecular targeted drugs would be effective for non-clear cell renal cell carcinoma (RCC), especially metastatic papillary RCC and chromophobe RCC? Question 64. Can it be more effective by targeting both the vascular endothelial growth factor receptor (VEGFR) and MET signaling pathways in sporadic metastatic papillary renal cell carcinoma (RCC)? Question 65. What are the predictive biomarkers that may be used to identify the renal cell carcinoma (RCC) patients who can benefit from immune checkpoint inhibitor treatment? Question 66. How do we identify predictive molecular biomarkers to stratify clear cell renal cell carcinoma patients for targeted therapies?
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Adlimoghaddam A, O’Donnell MJ, Quijada-Rodriguez A, Weihrauch D. Sodium–hydrogen exchangers in the nematode Caenorhabditis elegans: investigations towards their potential role in hypodermal H+ excretion, Na+ uptake, and ammonia excretion, as well as acid–base balance. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cation/proton exchangers of the cation proton antiporter 1 (CPA1) subfamily (NHEs, SLC 9) play an important role in many physiological processes, including cell volume regulation, acid–base homeostasis, and ammonia excretion. The soil nematode Caenorhabditis elegans (Maupas, 1900) (N2, 1968) expresses nine paralogues (NHX-1 to NHX-9). The current study was undertaken to investigate the role of the cation/proton exchanger in hypodermal Na+ and H+ fluxes, as well in ammonia excretion processes. Measurements using SIET (scanning ion-selective electrode technique) showed that the hypodermis promotes H+ secretion and Na+ uptake. Inhibitory effects on fluxes were observed upon application of amiloride but not EIPA, suggesting that NHXs are not involved in the transport processes. In response to stress induced by starvation or exposure to 1 mmol·L−1 NH4Cl, pH 5.5, or pH 8.0, body pH stayed fairly constant, with changes in mRNA expression levels detected in intestinal NHX-2 and hypodermal NHX-3. In conclusion, the study suggest that hypodermal apically localized EIPA-sensitive Na+/H+ exchangers do not likely play a role in ammonia excretion and Na+ uptake in the hypodermis of C. elegans, whereas apical amiloride-sensitive Na+ channels seem to be involved not just in hypodermal Na+ uptake but indirectly also in NH4+ and H+ excretion.
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Affiliation(s)
- Aida Adlimoghaddam
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | | | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Amiloride, An Old Diuretic Drug, Is a Potential Therapeutic Agent for Multiple Myeloma. Clin Cancer Res 2017; 23:6602-6615. [DOI: 10.1158/1078-0432.ccr-17-0678] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/30/2017] [Accepted: 07/28/2017] [Indexed: 11/16/2022]
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Levican J, Miranda-Cárdenas C, Soto-Rifo R, Aguayo F, Gaggero A, León O. Infectious pancreatic necrosis virus enters CHSE-214 cells via macropinocytosis. Sci Rep 2017; 7:3068. [PMID: 28596575 PMCID: PMC5465193 DOI: 10.1038/s41598-017-03036-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/21/2017] [Indexed: 12/22/2022] Open
Abstract
Infectious pancreatic necrosis virus (IPNV) is a non-enveloped virus belonging to the Birnaviridae family. IPNV produces an acute disease in salmon fingerlings, with high mortality rates and persistent infection in survivors. Although there are reports of IPNV binding to various cells, the viral receptor and entry pathways remain unknown. The aim of this study was to determine the endocytic pathway that allows for IPNV entry. We observed that IPNV stimulated fluid uptake and virus particles co-localysed with the uptake marker dextran in intracellular compartments, suggesting a role for macropinocytosis in viral entry. Consistent with this idea, viral infection was significantly reduced when the Na+/H+ exchanger NHE1 was inhibited with 5-(N-Ethyl-N-isopropyl) amiloride (EIPA). Neither chlorpromazine nor filipin complex I affected IPNV infection. To examine the role of macropinocytosis regulators, additional inhibitors were tested. Inhibitors of the EGFR pathway and the effectors Pak1, Rac1 and PKC reduced viral infection. Together, our results indicate that IPNV is mainly internalized into CHSE-214 cells by macropinocytosis.
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Affiliation(s)
- Jorge Levican
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Camila Miranda-Cárdenas
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ricardo Soto-Rifo
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Francisco Aguayo
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Aldo Gaggero
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Oscar León
- Programa de Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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Abstract
One of the differences between normal and cancer cells is lower pH of the extracellular space in tumors. Low pH in the extracellular space activates proteases and stimulates tumor invasion and metastasis. Tumor cells display higher level of the HIF1α transcription factor that promotes cell switch from mitochondrial respiration to glycolysis. The terminal product of glycolysis is lactate. Lactate formation from pyruvate is catalyzed by the specific HIF1α-dependent isoform of lactate dehydrogenase A. Because lactate accumulation is deleterious for the cell, it is actively exported by monocarboxylate transporters. Lactate is cotransported with proton, which acidifies the extracellular space. Another protein that contributes to proton concentration increase in the extracellular space is tumor-specific HIF1α-dependent carbonic anhydrase IX, which generates a proton in the reaction between carbon dioxide and water. The activity of Na+/H+ exchanger (another protein pump) is stimulated by stress factors (e.g. osmotic shock) and proliferation stimuli. This review describes the mechanisms of proton pump activation and reviews results of studies on effects of various proton pump inhibitors on tumor functioning and growth in cell culture and in vivo. The prospects of combined application of proton pump inhibitors and cytostatics in cancer therapy are discussed.
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Affiliation(s)
- V A Kobliakov
- Blokhin Russian Cancer Research Center, Russian Ministry of Health, Moscow, 115478, Russia.
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Kaminota T, Yano H, Shiota K, Nomura N, Yaguchi H, Kirino Y, Ohara K, Tetsumura I, Sanada T, Ugumori T, Tanaka J, Hato N. Elevated Na +/H + exchanger-1 expression enhances the metastatic collective migration of head and neck squamous cell carcinoma cells. Biochem Biophys Res Commun 2017; 486:101-107. [PMID: 28268168 DOI: 10.1016/j.bbrc.2017.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 03/03/2017] [Indexed: 01/13/2023]
Abstract
Cancer cells can migrate as collectives during invasion and/or metastasis; however, the precise molecular mechanisms of this form of migration are less clear compared with single cell migration following epithelial-mesenchymal transition. Elevated Na+/H+ exchanger1 (NHE1) expression has been suggested to have malignant roles in a number of cancer cell lines and in vivo tumor models. Furthermore, a metastatic human head and neck squamous cell carcinoma (HNSCC) cell line (SASL1m) that was isolated based on its increased metastatic potential also exhibited higher NHE1 expression than its parental line SAS. Time-lapse video recordings indicated that both cell lines migrate as collectives, although with different features, e.g., SASL1m was much more active and changed the direction of migration more frequently than SAS cells, whereas locomotive activities were comparable. SASL1m cells also exhibited higher invasive activity than SAS in Matrigel invasion assays. shRNA-mediated NHE1 knockdown in SASL1m led to reduced locomotive and invasive activities, suggesting a critical role for NHE1 in the collective migration of SASL1m cells. SASL1m cells also exhibited a higher metastatic rate than SAS cells in a mouse lymph node metastasis model, while NHE1 knockdown suppressed in vivo SASL1m metastasis. Finally, elevated NHE1 expression was observed in human HNSCC tissue, and Cariporide, a specific NHE1 inhibitor, reduced the invasive activity of SASL1m cells, implying NHE1 could be a target for anti-invasion/metastasis therapy.
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Affiliation(s)
- Teppei Kaminota
- Department of Otorhinolaryngology, Head and Neck Surgery, Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Hajime Yano
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Kohei Shiota
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan
| | - Noriko Nomura
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Haruna Yaguchi
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Yui Kirino
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Kentaro Ohara
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Issei Tetsumura
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Tomoyoshi Sanada
- Department of Otorhinolaryngology, Head and Neck Surgery, Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Toru Ugumori
- Department of Otorhinolaryngology, Head and Neck Surgery, Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
| | - Naohito Hato
- Department of Otorhinolaryngology, Head and Neck Surgery, Ehime University Medical School, 454, Shitsukawa, To-on, Ehime, 791-0295, Japan.
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Abstract
Frequently observed phenotypes of tumours include high metabolic activity, hypoxia and poor perfusion; these act to produce an acidic microenvironment. Cellular function depends on pH homoeostasis, and thus, tumours become dependent on pH regulatory mechanisms. Many of the proteins involved in pH regulation are highly expressed in tumours, and their expression is often of prognostic significance. The more acidic tumour microenvironment also has important implications with regard to chemotherapeutic and radiotherapeutic interventions. In addition, we review pH-sensing mechanisms, the role of pH regulation in tumour phenotype and the use of pH regulatory mechanisms as therapeutic targets.
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Affiliation(s)
- Alan McIntyre
- Molecular Oncology Laboratories, Department of Medical Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Adrian L Harris
- Molecular Oncology Laboratories, Department of Medical Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
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