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El Salamouni NS, Buckley BJ, Lee R, Ranson M, Kelso MJ, Yu H. Ion Transport and Inhibitor Binding by Human NHE1: Insights from Molecular Dynamics Simulations and Free Energy Calculations. J Phys Chem B 2024; 128:440-450. [PMID: 38185879 DOI: 10.1021/acs.jpcb.3c05863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The human Na+/H+ exchanger (NHE1) plays a crucial role in maintaining intracellular pH by regulating the electroneutral exchange of a single intracellular H+ for one extracellular Na+ across the plasma membrane. Understanding the molecular mechanisms governing ion transport and the binding of inhibitors is of importance in the development of anticancer therapeutics targeting NHE1. In this context, we performed molecular dynamics (MD) simulations based on the recent cryo-electron microscopy (cryo-EM) structures of outward- and inward-facing conformations of NHE1. These simulations allowed us to explore the dynamics of the protein, examine the ion-translocation pore, and confirm that Asp267 is the ion-binding residue. Our free energy calculations did not show a significant difference between Na+ and K+ binding at the ion-binding site. Consequently, Na+ over K+ selectivity cannot be solely explained by differences in ion binding. Our MD simulations involving NHE1 inhibitors (cariporide and amiloride analogues) maintained stable interactions with Asp267 and Glu346. Our study highlights the importance of the salt bridge between the positively charged acylguanidine moiety and Asp267, which appears to play a role in the competitive inhibitory mechanism for this class of inhibitors. Our computational study provides a detailed mechanistic interpretation of experimental data and serves the basis of future structure-based inhibitor design.
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Affiliation(s)
- Nehad S El Salamouni
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Benjamin J Buckley
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Richmond Lee
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Marie Ranson
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Michael J Kelso
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Haibo Yu
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- ARC Centre of Excellence in Quantum Biotechnology, University of Wollongong, Wollongong, NSW 2522, Australia
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Zhu X, Ma K, Zhou K, Pan X, Liu J, Nürnberg B, Alesutan I, Völkl J, Lang F. Requirement of Na+/H+ Exchanger NHE1 for Vasopressin-Induced Osteogenic Signaling and Calcification in Human Aortic Smooth Muscle Cells. Kidney Blood Press Res 2022; 47:399-409. [PMID: 35339998 DOI: 10.1159/000524050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/07/2022] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND/AIMS Vasopressin is a powerful stimulator of vascular calcification, augmenting osteogenic signaling in vascular smooth muscle cells (VSMCs) including upregulation of transcription factors such as core-binding factor α-1 (CBFA1), msh homeobox 2 (MSX2), and SRY-Box 9 (SOX9), as well as of tissue-nonspecific alkaline phosphatase (ALPL). Vasopressin-induced osteogenic signaling and calcification require the serum- and glucocorticoid-inducible kinase 1 (SGK1). Known effects of SGK1 include upregulation of Na+/H+ exchanger 1 (NHE1). NHE1 further participates in the regulation of reactive oxygen species (ROS). NHE1 has been shown to participate in the orchestration of bone mineralization. The present study, thus, explored whether vasopressin modifies NHE1 expression and ROS generation, as well as whether pharmacological inhibition of NHE1 disrupts vasopressin-induced osteogenic signaling and calcification in VSMCs. METHODS Human aortic smooth muscle cells (HAoSMCs) were treated with vasopressin in the absence or presence of SGK1 silencing, SGK1 inhibitor GSK-650394, and NHE1 blocker cariporide. Transcript levels were determined by using quantitative real-time polymerase chain reaction, protein abundance by Western blotting, ROS generation with 2',7'-dichlorofluorescein diacetate fluorescence, and ALP activity and calcium content by using colorimetric assays. RESULTS Vasopressin significantly enhanced the NHE1 transcript and protein levels in HAoSMCs, effects significantly blunted by SGK1 inhibition with GSK-650394 or SGK1 silencing. Vasopressin increased ROS accumulation, an effect significantly blocked by the NHE1 inhibitor cariporide. Vasopressin further significantly increased osteogenic markers CBFA1, MSX2, SOX9, and ALPL transcript levels, as well as ALP activity and calcium content in HAoSMCs, all effects significantly blunted by SGK1 silencing or in the presence of GSK-650394 or cariporide. CONCLUSION Vasopressin stimulates NHE1 expression and ROS generation, an effect dependent on SGK1 and required for vasopressin-induced stimulation of osteogenic signaling and calcification of VSMCs.
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Affiliation(s)
- Xuexue Zhu
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
| | - Ke Ma
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
| | - Kuo Zhou
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
| | - Xia Pan
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
| | - Jibin Liu
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
| | - Ioana Alesutan
- Institute for Physiology and Pathophysiology, Johannes Kepler University Linz, Linz, Austria
| | - Jakob Völkl
- Institute for Physiology and Pathophysiology, Johannes Kepler University Linz, Linz, Austria.,Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Florian Lang
- Department of Physiology, Eberhard-Karls-University of Tübingen, Tübingen, Germany
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Angus M, Ruben P. Voltage gated sodium channels in cancer and their potential mechanisms of action. Channels (Austin) 2019; 13:400-409. [PMID: 31510893 PMCID: PMC6768049 DOI: 10.1080/19336950.2019.1666455] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/30/2019] [Accepted: 09/08/2019] [Indexed: 01/22/2023] Open
Abstract
Voltage gated sodium channels (VGSC) are implicated in cancer cell invasion and metastasis. However, the mechanism by which VGSC increase cell invasiveness and probability of metastasis is still unknown. In this review we outline lesser known functions of VGSC outside of action potential propagation, and the current understanding of the effects of VGSC in cancer. Finally, we discuss possible downstream effects of VGSC activation in cancer cells. After extensive review of the literature, the most likely role of VGSC in cancer is in the invadopodia, the leading edge of metastatic cancer cells. Sodium gradients are used to drive many biological processes in the body, and invadopodia may be similar. The function of the sodium hydrogen exchanger (NHE) and sodium calcium exchanger (NCX) are driven by sodium gradients. Voltage gated calcium channels, activated by membrane depolarization, are also capable of becoming activated in response to VGSC activity. Changes to hydrogen ion exchange or calcium handling have functional consequences for invadopodia and would explain the relationship between VGSC expression and invasiveness of cancer cells.
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Affiliation(s)
- Madeline Angus
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Peter Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Wang P, Wang X, Li L, Kan Q, Yu Z, Feng R, Chen Z, Shi Y, Gao J. Role of sodium-hydrogen exchanger isoform 1 in regulating hepatocyte apoptosis induced by hyperammonaemia. GASTROENTEROLOGIA Y HEPATOLOGIA 2018; 41:490-497. [PMID: 30033048 DOI: 10.1016/j.gastrohep.2018.05.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND The "secondary injury" theory of liver failure indicated that hyperammonaemia due to liver failure causes further deterioration of hepatocytes. Our previous studies have demonstrated that high blood ammonia levels may lead to hepatocyte apoptosis, as NH4Cl loading caused metabolic acidosis and an increase in sodium-hydrogen exchanger isoform 1 (NHE1). In this study, we established a hyperammonia hepatocyte model to determine the role of NHE1 in the regulation of hepatocyte apoptosis induced by NH4Cl. MATERIALS AND METHODS In current studies, intracellular pH (pHi) and NHE1 activity were analyzed using the pHi-sensitive dye BCECF-AM. The results showed that intracellular pH dropped and NHE1 activity increased in hepatocytes under NH4Cl treatment. As expected, decreased pHi induced by NH4Cl was associated with increased apoptosis, low cell proliferation and ATP depletion, which was exacerbated by exposure to the NHE1 inhibitor cariporide. We also found that NH4Cl treatment stimulated PI3K and Akt phosphorylation and this effect was considerably reduced by NHE1 inhibition. CONCLUSION This study highlighted the significant role of NHE1 in the regulation of cell apoptosis induced by hyperammonaemia.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Xin Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China.
| | - Ling Li
- Department of Palliative and Hospice Care, The Ninth People's Hospital of Zhengzhou, Henan, PR China
| | - Quancheng Kan
- Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
| | - Zujiang Yu
- Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
| | - Rongfang Feng
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China
| | - ZiXiao Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Yan Shi
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China
| | - Jinling Gao
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan, PR China
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5
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Xia J, Huang N, Huang H, Sun L, Dong S, Su J, Zhang J, Wang L, Lin L, Shi M, Bin J, Liao Y, Li N, Liao W. Voltage-gated sodium channel Nav 1.7 promotes gastric cancer progression through MACC1-mediated upregulation of NHE1. Int J Cancer 2016; 139:2553-69. [PMID: 27529686 DOI: 10.1002/ijc.30381] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 07/19/2016] [Accepted: 07/26/2016] [Indexed: 12/20/2022]
Abstract
Voltage-gated sodium channels (VGSCs), which are aberrantly expressed in several human cancers, affect cancer cell behavior; however, their role in gastric cancer (GC) and the link between these channels and tumorigenic signaling remain unclear. The aims of this study were to determine the clinicopathological significance and role of the VGSC Nav 1.7 in GC progression and to investigate the associated mechanisms. Here, we report that the SCN9A gene encoding Nav 1.7 was the most abundantly expressed VGSC subtype in GC tissue samples and two GC cell lines (BGC-823 and MKN-28 cells). SCN9A expression levels were also frequently found to be elevated in GC samples compared to nonmalignant tissues by real-time PCR. In the 319 GC specimens evaluated by immunohistochemistry, Nav 1.7 expression was correlated with prognosis, and transporter Na(+) /H(+) exchanger-1 (NHE1) and oncoprotein metastasis-associated in colon cancer-1 (MACC1) expression. Nav 1.7 suppression resulted in reduced voltage-gated sodium currents, decreased NHE1 expression, increased extracellular pH and decreased intracellular pH, and ultimately, reduced invasion and proliferation rates of GC cells and growth of GC xenografts in nude mice. Nav 1.7 inhibition led to reduced MACC1 expression, while MACC1 inhibition resulted in reduced NHE1 expression in vitro and in vivo. Mechanistically, the suppression of Nav 1.7 decreased NF-κB p65 nuclear translocation via p38 activation, thus reducing MACC1 expression. Downregulation of MACC1 decreased c-Jun phosphorylation and subsequently reduced NHE1 expression, whereas the addition of hepatocyte growth factor (HGF), a c-Met physiological ligand, reversed the effect. These results indicate that Nav 1.7 promotes GC progression through MACC1-mediated upregulation of NHE1. Therefore, Nav 1.7 is a potential prognostic marker and/or therapeutic target for GC.
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Affiliation(s)
- Jianling Xia
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Na Huang
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Hongxiang Huang
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Li Sun
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Shaoting Dong
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Jinyu Su
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jingwen Zhang
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Lin Wang
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Li Lin
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Min Shi
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Jianping Bin
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yulin Liao
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Nailin Li
- Karolinska Institute, Department of Medicine-Solna, Clinical Pharmacology Group, Karolinska University Hospital-Solna, Stockholm, 17176, Sweden
| | - Wangjun Liao
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
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Jenkins EC, Debnath S, Varriano S, Gundry S, Fata JE. Na+/H+exchanger 1 (NHE1) function is necessary for maintaining mammary tissue architecture. Dev Dyn 2013; 243:229-42. [DOI: 10.1002/dvdy.24032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/18/2013] [Accepted: 08/02/2013] [Indexed: 12/20/2022] Open
Affiliation(s)
- Edmund C. Jenkins
- Department of Biology; College of Staten Island; Staten Island New York
- Biology Doctoral Program; City University of New York Graduate Center; New York New York
| | - Shawon Debnath
- Department of Biology; College of Staten Island; Staten Island New York
- Biochemistry Doctoral Program; City University of New York Graduate Center; New York New York
| | - Sophia Varriano
- Department of Biology; College of Staten Island; Staten Island New York
| | - Stephen Gundry
- Electrical Engineering Doctoral Program; City College of New York, The City University of New York; New York New York
| | - Jimmie E. Fata
- Department of Biology; College of Staten Island; Staten Island New York
- Biology Doctoral Program; City University of New York Graduate Center; New York New York
- Biochemistry Doctoral Program; City University of New York Graduate Center; New York New York
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Hyperosmolarity attenuates TNF-α-mediated proinflammatory activation of human pulmonary microvascular endothelial cells. Shock 2013; 39:366-72. [PMID: 23364439 DOI: 10.1097/shk.0b013e3182894016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Firm neutrophil (PMN)-endothelial (EC) adhesion is crucial to the PMN-mediated hyperinflammation observed in acute lung injury. Hypertonic saline (HTS) used for resuscitation of hemorrhagic shock has been associated with a decreased incidence of PMN-mediated lung injury/acute respiratory distress syndrome. We hypothesize that physiologically accessible hypertonic incubation (170 vs. 140 mM, osmolarity ranging from 360 to 300 mOsm/L) inhibits proinflammatory activation of human pulmonary microvascular endothelial cells (HMVECs). Proinflammatory activation of HMVECs was investigated in response to tumor necrosis factor-α (TNF-α), including interleukin 8 (IL-8) release, intercellular adhesion molecule 1 (ICAM-1) surface expression, PMN adhesion, and signaling mechanisms under both isotonic (control) and hypertonic conditions. Hyperosmolarity alone had no effect on either basal IL-8 release or ICAM-1 surface expression but did lead to concentration-dependent decreases in TNF-α-induced IL-8 release, ICAM-1 surface expression, and PMN-HMVEC adhesion. Conversely, HTS activated p38 mitogen-activated protein kinase (MAPK) and enhanced TNF-α activation of p38 MAPK. Despite this basal activation, hyperosmolar incubation attenuated TNF-α-stimulated IL-8 release and ICAM-1 surface expression and subsequent PMN adherence, while p38 MAPK inhibition did not further influence the effects of hyperosmolar conditions on ICAM-1 surface expression. In addition, TNF-α induced nuclear factor-κB DNA binding, but HTS conditions attenuated this by 31% (P < 0.01). In conclusion, HTS reduces PMN-HMVEC adhesion and TNF-α-induced proinflammatory activation of primary HMVECs via attenuation of nuclear factor-κB signaling.
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Jenkins EC, Debnath S, Gundry S, Gundry S, Uyar U, Fata JE. Intracellular pH regulation by Na+/H+ exchanger-1 (NHE1) is required for growth factor-induced mammary branching morphogenesis. Dev Biol 2012; 365:71-81. [DOI: 10.1016/j.ydbio.2012.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 01/30/2012] [Accepted: 02/09/2012] [Indexed: 01/19/2023]
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Yang W, Bhandaru M, Pasham V, Bobbala D, Zelenak C, Jilani K, Rotte A, Lang F. Effect of Thymoquinone on Cytosolic pH and Na +/H + Exchanger Activity in Mouse Dendritic Cells. Cell Physiol Biochem 2012; 29:21-30. [DOI: 10.1159/000337583] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2012] [Indexed: 01/13/2023] Open
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NHE1 activity contributes to migration and is necessary for proliferation of human gastric myofibroblasts. Pflugers Arch 2011; 463:459-75. [PMID: 22138972 DOI: 10.1007/s00424-011-1059-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 10/31/2011] [Accepted: 11/02/2011] [Indexed: 11/25/2022]
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Koutsogiannaki S, Kaloyianni M. Effect of 17β-estradiol on adhesion of Mytilus galloprovincialis hemocytes to selected substrates. Role of alpha2 integrin subunit. FISH & SHELLFISH IMMUNOLOGY 2011; 31:73-80. [PMID: 21524703 DOI: 10.1016/j.fsi.2011.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/30/2011] [Accepted: 04/11/2011] [Indexed: 05/30/2023]
Abstract
The process of hemocyte adhesion to extracellular matrix (ECM) proteins plays a crucial role in cell immunity. In most of these interactions between ECM proteins and cells, integrins are involved. The results of the present study showed that incubation of Mytilus galloprovincialis hemocytes with 17β-estradiol caused significant increased adhesion of hemocytes to ECM proteins and specifically to laminin-1, collagen IV and oxidized collagen IV, in relation to control cells. The adhesion of hemocytes to oxidized collagen was significantly higher than to either collagen IV or to laminin-1. In accordance with this, inhibition of either NADPH oxidase or nitric oxide (NO) synthase attenuated 17β-estradiol effect on hemocyte adhesion, suggesting that the high levels of free radicals, produced after 17β-estradiol effect, could contribute to the high adhesion of hemocytes to laminin-1 and collagen IV. The implication of ROS was further confirmed by the use of the oxidant rotenone, which caused elevation of cell adhesion in relation to control and by the antioxidant NAC which attenuated 17β-estradiol effect. The mechanism of 17β-estradiol induced adhesion to laminin-1, collagen IV and oxidized collagen IV involves a large number of intracellular components, as Na+/H+ exchanger (NHE), all isoforms of protein kinase C (PKC), phosphatidylinositol-3-kinase (PI3K) and c-jun N-terminal kinase (JNK) as well as alpha2 integrin subunit. Maintenance of high cyclic adenosine-3'-5'-monophosphate (cAMP) levels caused non significant higher adhesion of hemocytes to ECM proteins in relation to control cells. Our results showed that 17β-estradiol caused a significant increase in α₂ integrin subunit levels, which was reduced after inhibition of NHE, PI3K, PKC, NO synthase, NADPH oxidase and JNK. In addition, our results showed that apart from 17β-estradiol, high cAMP and high ROS levels caused significantly higher induction of α₂ integrin subunit levels in relation to control. Our results imply a potential involvement of cAMP in immune responses of Mytilus hemocytes, which needs further investigation.
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Affiliation(s)
- Sophia Koutsogiannaki
- Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Gilligan DM, Finney GL, Rynes E, Maccoss MJ, Lambert AJ, Peters LL, Robledo RF, Wooden JM. Comparative proteomics reveals deficiency of NHE-1 (Slc9a1) in RBCs from the beta-adducin knockout mouse model of hemolytic anemia. Blood Cells Mol Dis 2011; 47:85-94. [PMID: 21592827 DOI: 10.1016/j.bcmd.2011.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/22/2011] [Indexed: 11/29/2022]
Abstract
Hemolytic anemia is one of the most common inherited disorders. To identify candidate proteins involved in hemolytic anemia pathophysiology, we utilized a label-free comparative proteomic approach to detect differences in RBCs from normal and beta-adducin (Add2) knock-out mice. We detected 7 proteins that were decreased and 48 proteins that were increased in the beta-adducin knock-out RBC ghost. Since hemolytic anemias are characterized by reticulocytosis, we compared reticulocyte-enriched samples from phenylhydrazine-treated mice with mature RBCs from untreated mice. Label-free analysis identified 47 proteins that were increased in the reticulocyte-enriched samples and 21 proteins that were decreased. Among the proteins increased in Add2 knockout RBCs, only 11 were also found increased in reticulocytes. Among the proteins decreased in Add2 knockout RBCs, beta- and alpha-adducin showed the greatest intensity difference, followed by NHE-1 (Slc9a1), the sodium-hydrogen exchanger. We verified these mass spectrometry results by immunoblot. This is the first example of a deficiency of NHE-1 in hemolytic anemia and suggests new insights into the mechanisms leading to fragile RBCs. Our use of label-free comparative proteomics to make this discovery demonstrates the usefulness of this approach as opposed to metabolic or chemical isotopic labeling of mice.
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Affiliation(s)
- Diana M Gilligan
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA.
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Basic structural and functional characteristics of the epidermal barrier in wild mammals living in different habitats and climates. EUR J WILDLIFE RES 2011. [DOI: 10.1007/s10344-011-0499-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Ozkucur N, Perike S, Sharma P, Funk RHW. Persistent directional cell migration requires ion transport proteins as direction sensors and membrane potential differences in order to maintain directedness. BMC Cell Biol 2011; 12:4. [PMID: 21255452 PMCID: PMC3042415 DOI: 10.1186/1471-2121-12-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 01/22/2011] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Ion transport proteins generate small electric fields that can induce directional cell motility; however, little is known about their mechanisms that lead to directedness. We investigated Na, K-ATPase (NaKA) and Na+/H+ exchanger isoforms (NHE1 and 3) in SaOS-2 and Calvarial osteoblasts, which present anode- and cathode- directed motility, during electrotaxis. RESULTS Significant colocalizations of NaKA with vinculin and pNHE3 with ß-actin were observed to occur at the leading edges of cells. The directedness were attenuated when NaKA or NHE3 was inhibited, confirming their implication in directional sensing. Depending on the perceived direction, a divergent regulation in PIP2 levels as a function of NHE3 and NaKA levels was observed, suggesting that PIP2 may act as a spatiotemporal regulator of the cell membrane during electrotaxis. Moreover, at the same places where pNHE3 accumulates, bubble-shaped H+ clouds were observed, suggesting a physio-mechanical role for NHE3. The cell membrane becomes hyperpolarized at the front and depolarized at the back, which confirms NaKA activity at the leading edge. CONCLUSION We suggest a novel role for both NaKA and NHE3 that extends beyond ion translocation and conclude that they can act as directional sensors and Vmem as a regulatory cue which maintain the persistent direction in electrotaxis.
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Affiliation(s)
- Nurdan Ozkucur
- Department of Anatomy, Medical Faculty Carl Gustav Carus, Technical University of Dresden, Dresden, Germany.
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Banakou E, Dailianis S. Involvement of Na+/H+ exchanger and respiratory burst enzymes NADPH oxidase and NO synthase, in Cd-induced lipid peroxidation and DNA damage in haemocytes of mussels. Comp Biochem Physiol C Toxicol Pharmacol 2010; 152:346-52. [PMID: 20541622 DOI: 10.1016/j.cbpc.2010.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/03/2010] [Accepted: 06/03/2010] [Indexed: 11/26/2022]
Abstract
This study investigated cadmium-induced oxidative and genotoxic effects, such as lipid peroxidation and disturbance of DNA integrity (DNA damage) in haemocytes of mussel Mytilus galloprovincialis and the possible involvement of Na+/H+ exchanger (NHE), and/or the main enzymes of respiratory burst, NADPH oxidase and nitric oxide (NO) synthase, in the induction of Cd toxic effects. In order to verify the role of either NHE, or NADPH oxidase and NO synthase in Cd-mediated toxicity, inhibitors such as ethyl-N-isopropyl-amiloride (EIPA), diphenyleneiodonium chloride (DPI) and NG-nitro-L-arginine methyl ester (L-NAME) were used in each case. Moreover, phorbol-myristate acetate (PMA), a well-known protein kinase C (PKC)-mediated NADPH oxidase and NO synthase stimulator, as well as hydrogen peroxide (H2O2), a well-known genotoxic agent, was also used for elucidating the modulation of signaling molecules within cells, thus leading to the induction of lipid peroxidation and DNA damage. The results of the present study showed that micromolar concentrations of Cd (0.05-50 microM) could enhance both lipid peroxidation and DNA damage, possible via a PKC-mediated signaling pathway with the involvement of NHE, thus leading to the induction of NADPH oxidase and NO synthase activity, since inhibition of either NHE, or NADPH oxidase and NO synthase activity, significantly attenuates Cd-induced toxic effects in each case.
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Affiliation(s)
- Eleni Banakou
- Section of Animal Biology, Department of Biology, Faculty of Sciences, University of Patras, 26 500 Patra, Greece
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Dailianis S, Patetsini E, Kaloyianni M. The role of signalling molecules on actin glutathionylation and protein carbonylation induced by cadmium in haemocytes of mussel Mytilus galloprovincialis (Lmk). ACTA ACUST UNITED AC 2010; 212:3612-20. [PMID: 19880721 DOI: 10.1242/jeb.030817] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This study investigated the role of Na(+)/H(+) exchanger (NHE) and signalling molecules, such as cAMP, PKC, PI 3-kinase, and immune defence enzymes, NADPH oxidase and nitric oxide synthase, in the induction of protein glutathionylation and carbonylation in cadmium-treated haemocytes of mussel Mytilus galloprovincialis. Glutathionylation was detected by western blot analysis and showed actin as its main target. A significant increase of both actin glutathionylation and protein carbonylation, were observed in haemocytes exposed to micromolar concentration of cadmium chloride (5 micromol l(-1)). Cadmium seems to cause actin polymerization that may lead to its increased glutathionylation, probably to protect it from cadmium-induced oxidative stress. It is therefore possible that polymerization of actin plays a signalling role in the induction of both glutathionylation and carbonylation processes. NHE seems to play a regulatory role in the induction of oxidative damage and actin glutathionylation, since its inhibition by 2 micromol l(-1) cariporide, significantly diminished cadmium effects in each case. Similarly, attenuation of cadmium effects were observed in cells pre-treated with either 11 micromol l(-1) GF-109203X, a potent inhibitor of PKC, 50 nmol l(-1) wortmannin, an inhibitor of PI 3-kinase, 0.01 mmol l(-1) forskolin, an adenylyl cyclase activator, 10 micromol l(-1) DPI, a NADPH oxidase inhibitor, or 10 micromol l(-1) L-NAME, a nitric oxide synthase inhibitor, suggesting a possible role of PKC, PI 3-kinase and cAMP, as well as NADPH oxidase and nitric oxide synthase in the enhancement of cadmium effects on both actin glutathionylation and protein carbonylation.
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Konstantinidis D, Paletas K, Koliakos G, Kaloyianni M. The ambiguous role of the Na+-H+ exchanger isoform 1 (NHE1) in leptin-induced oxidative stress in human monocytes. Cell Stress Chaperones 2009; 14:591-601. [PMID: 19301149 PMCID: PMC2866947 DOI: 10.1007/s12192-009-0110-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2008] [Revised: 03/03/2009] [Accepted: 03/06/2009] [Indexed: 01/24/2023] Open
Abstract
Leptin, a 16-kDa cytokine produced mainly by the adipose tissue, is known to increase energy expenditure while at the same time lowering food intake by acting directly on the hypothalamus. ObRb, the leptin receptor mostly involved in intracellular signaling, is expressed in a wide range of tissues, thus allowing leptin to affect a much broader diversity of biological processes. High concentrations of leptin are encountered in patients with hyperleptinemia, a condition which very often accompanies obesity and which is a direct result of leptin resistance. In the present study, moderate and high concentrations of leptin (16 and 160 ng/ml) were mostly utilized in order to investigate the role of this cytokine in oxidative stress levels in human monocytes. Leptin was found to increase oxidative species production as measured with 2',7'-dichlorodihydrofluorescein diacetate (general marker of oxidative species, but not O2-*) and dihydroethidium (marker of O2-*). Surprisingly, it also augmented superoxide dismutase activity. Inhibition of the Na+-H+ exchanger isoform 1 (NHE1) also inhibited leptin-induced superoxide anion production but at the same time amplified leptin-induced production of other oxidative species. Signaling proteins such as phosphoinositide 3 kinase and conventional isoforms of protein kinase C (alpha-, beta(i)-, beta(ii)-), as well as NADPH oxidase, also participated in leptin signaling. Finally, leptin was found to increase glutathionylation levels of NHE1-bound heat shock protein 70 kDa (Hsp70) but not Hsp70 binding to NHE1.
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Affiliation(s)
- Diamantis Konstantinidis
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124 Greece
| | - Konstantinos Paletas
- Laboratory for the Study of Metabolic Diseases, B’ Medical Clinic, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - George Koliakos
- Laboratory of Biological Chemistry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, 54124 Greece
| | - Martha Kaloyianni
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124 Greece
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Mandal A, Shahidullah M, Delamere NA, Terán MA. Elevated hydrostatic pressure activates sodium/hydrogen exchanger-1 in rat optic nerve head astrocytes. Am J Physiol Cell Physiol 2009; 297:C111-20. [PMID: 19419999 DOI: 10.1152/ajpcell.00539.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Optic nerve head astrocytes become abnormal in eyes that have elevated intraocular pressure, and cultured astrocytes display altered protein expression after being subjected for > or = 1 days to elevated hydrostatic pressure. Here we show that 2-h elevated hydrostatic pressure (15 or 30 mmHg) causes phosphorylation of ERK1/2, ribosomal S6 protein kinase (p90(RSK)), and Na/H exchanger (NHE)1 in cultured rat optic nerve head astrocytes as judged by Western blot analysis. The MEK/ERK inhibitor U0126 abolished phosphorylation of NHE1 and p90(RSK) as well as ERK1/2. To examine NHE1 activity, cytoplasmic pH (pH(i)) was measured with BCECF and, in some experiments, cells were acidified by 5-min exposure to 20 mM ammonium chloride. Although baseline pH(i) was unaltered, the rate of pH(i) recovery from acidification was fourfold higher in pressure-treated astrocytes. In the presence of either U0126 or dimethylamiloride (DMA), an NHE inhibitor, hydrostatic pressure did not change the rate of pH(i) recovery. The findings are consistent with NHE1 activation due to phosphorylation of ERK1/2, p90(RSK), and NHE1 that occurs in response to hydrostatic pressure. These responses may precede long-term changes of protein expression known to occur in pressure-stressed astrocytes.
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Affiliation(s)
- Amritlal Mandal
- Dept. of Physiology, Univ. of Arizona, Tucson, AZ 85724, USA
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