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Xue XL, Wang Y, Chen S, Wang KP, Niu SY, Zong QS, Jiang Y, Hu ZQ. Monitoring intracellular pH using a hemicyanine-based ratiometric fluorescent probe. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 284:121778. [PMID: 36049300 DOI: 10.1016/j.saa.2022.121778] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/03/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Monitoring intracellular pH using ratiometric fluorescent probes can provide further insights into various biological processes including many diseases. Although ratiometric fluorescent probes with dual emission can efficiently exclude interferences (probe concentration, instrumental efficiency, and environmental conditions) compared with traditional off-on fluorescent probes, development of pH-responsive fluorescent probes with dual emission remains relatively unexplored and challenging. Herein we reported a new hemicyanine-based ratiometric fluorescent probe 1 with a hydroxyl group. The probe 1 exhibits dual emission and shows a real-time and selective fluorescence response to micro-environmental pH conditions in a range of 6.0 ∼ 8.0. Further studies revealed that 1 could exclusively enter and accumulate into mitochondria and monitor the pH micro-environmental conditions through fluorescence imaging in HepG2 cells. We suggest that this probe might be used as a probe to elucidate the role of pH in many physiological processes.
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Affiliation(s)
- Xiao-Lei Xue
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Yang Wang
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Shaojin Chen
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Kun-Peng Wang
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Shu-Yan Niu
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Qian-Shou Zong
- College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, PR China.
| | - Yi Jiang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 P.R. China.
| | - Zhi-Qiang Hu
- Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, Key Laboratory of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
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2
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Xia H, Zahra A, Jia M, Wang Q, Wang Y, Campbell SL, Wu J. Na +/H + Exchanger 1, a Potential Therapeutic Drug Target for Cardiac Hypertrophy and Heart Failure. Pharmaceuticals (Basel) 2022; 15:ph15070875. [PMID: 35890170 PMCID: PMC9318128 DOI: 10.3390/ph15070875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023] Open
Abstract
Cardiac hypertrophy is defined as increased heart mass in response to increased hemodynamic requirements. Long-term cardiac hypertrophy, if not counteracted, will ultimately lead to heart failure. The incidence of heart failure is related to myocardial infarction, which could be salvaged by reperfusion and ultimately invites unfavorable myocardial ischemia-reperfusion injury. The Na+/H+ exchangers (NHEs) are membrane transporters that exchange one intracellular proton for one extracellular Na+. The first discovered NHE isoform, NHE1, is expressed almost ubiquitously in all tissues, especially in the myocardium. During myocardial ischemia-reperfusion, NHE1 catalyzes increased uptake of intracellular Na+, which in turn leads to Ca2+ overload and subsequently myocardial injury. Numerous preclinical research has shown that NHE1 is involved in cardiac hypertrophy and heart failure, but the exact molecular mechanisms remain elusive. The objective of this review is to demonstrate the potential role of NHE1 in cardiac hypertrophy and heart failure and investigate the underlying mechanisms.
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Affiliation(s)
- Huiting Xia
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China; (H.X.); (A.Z.)
| | - Aqeela Zahra
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China; (H.X.); (A.Z.)
| | - Meng Jia
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China; (M.J.); (Q.W.)
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100070, China
- National Clinical Research Center for Neurological Disease, Beijing 100070, China
| | - Qun Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China; (M.J.); (Q.W.)
- National Clinical Research Center for Neurological Disease, Beijing 100070, China
| | - Yunfu Wang
- Taihe Hospital, Hubei University of Medicine, Shiyan 440070, China;
| | - Susan L. Campbell
- Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA;
| | - Jianping Wu
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China; (H.X.); (A.Z.)
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China; (M.J.); (Q.W.)
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100070, China
- National Clinical Research Center for Neurological Disease, Beijing 100070, China
- Correspondence:
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3
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Wu Y, Weil T. Recent Developments of Nanodiamond Quantum Sensors for Biological Applications. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200059. [PMID: 35343101 PMCID: PMC9259730 DOI: 10.1002/advs.202200059] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/23/2022] [Indexed: 05/09/2023]
Abstract
Measuring certain quantities at the nanoscale is often limited to strict conditions such as low temperature or vacuum. However, the recently developed nanodiamond (ND) quantum sensing technology shows great promise for ultrasensitive diagnosis and probing subcellular parameters at ambient conditions. Atom defects (i.e., N, Si) within the ND lattice provide stable emissions and sometimes spin-dependent photoluminescence. These unique properties endow ND quantum sensors with the capacity to detect local temperature, magnetic fields, electric fields, or strain. In this review, some of the recent, most exciting developments in the preparation and application of ND sensors to solve current challenges in biology and medicine including ultrasensitive detection of virions and local sensing of pH, radical species, magnetic fields, temperature, and rotational movements, are discussed.
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Affiliation(s)
- Yingke Wu
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
| | - Tanja Weil
- Max Planck Institute for Polymer ResearchAckermannweg 10Mainz55128Germany
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4
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Li N, Zhou H. Sodium-glucose Cotransporter Type 2 Inhibitors: A New Insight into the Molecular Mechanisms of Diabetic Nephropathy. Curr Pharm Des 2022; 28:2131-2139. [PMID: 35718973 DOI: 10.2174/1381612828666220617153331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 03/15/2022] [Indexed: 11/22/2022]
Abstract
Diabetic nephropathy is one of the chronic microvascular complications of diabetes and is a leading cause of end-stage renal disease. Fortunately, clinical trials have demonstrated that sodium-glucose cotransporter type 2 inhibitors could decrease proteinuria and improve renal endpoints and are promising agents for the treatment of diabetic nephropathy. The renoprotective effects of sodium-glucose cotransporter type 2 inhibitors cannot be simply attributed to their advantages in aspects of metabolic benefits, such as glycemic control, lowering blood pressure, and control of serum uric acid, or improving hemodynamics associated with decreased glomerular filtration pressure. Some preclinical evidence suggests that sodium-glucose cotransporter type 2 inhibitors exert their renoprotective effects by multiple mechanisms, including attenuation of oxidative and endoplasmic reticulum stresses, anti-fibrosis and anti-inflammation, protection of podocytes, suppression of megalin function, improvement of renal hypoxia, restored mitochondrial dysfunction and autophagy, as well as inhibition of sodium-hydrogen exchanger 3. In the present study, the detailed molecular mechanisms of sodium-glucose cotransporter type 2 inhibitors with the actions of diabetic nephropathy were reviewed, with the purpose of providing the basis for drug selection for the treatment of diabetic nephropathy.
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Affiliation(s)
- Na Li
- Department of Endocrinology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hong Zhou
- Department of Endocrinology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
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5
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Arya JK, Kumar R, Tripathi SS, Rizvi SI. Hormetic effect of 3-Bromopyruvate on age-induced alterations in erythrocyte membrane transporters and oxidative biomarkers in rats. Rejuvenation Res 2022; 25:122-128. [DOI: 10.1089/rej.2021.0060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Jitendra Kumar Arya
- University of Allahabad, Department of Biochemistry, allahabad, ALLAHABAD, UTTAR PRADESH, India, 211002
| | - Raushan Kumar
- University of Allahabad, Department of Biochemistry, Allahabad, Uttar Pradesh, India
| | - Shambhoo Sharan Tripathi
- University of Allahabad, Department of Biochemistry, Fauclty of Science, UNIVERSITY OF ALLAHABAD, PRYAGRAJ, Uttar Pradesh, India, 211002
| | - Syed Ibrahim Rizvi
- University of Allahabad, Department of Biochemistry, faculty of Science, Allahabad, Uttar Pradesh, India, 211002
- India
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6
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Yang Q, Zhang X, Song Y, Li K, Shi H, Xiao H, Ma Y. Label-Free in Situ pH Monitoring in a Single Living Cell Using an Optical Nanoprobe. ACTA ACUST UNITED AC 2020; 3. [PMID: 33073180 DOI: 10.1002/mds3.10079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Intracellular pH plays critical roles in cell and tissue functions during processes such as metabolism, proliferation, apoptosis, ion transportation, endocytosis, muscle contraction and so on. It is thus an important biomarker that can readily be used to monitor the physiological status of a cell. Thus, disrupted intracellular pH may serve as an early indicator of cell dysfunction and deterioration. Various methods have been developed to detect cellular pH, such as pH-sensitive labeling reagents with fluorescent or Raman signals. However, excessive cellular uptake of these reagents will not only disrupt cell viability but also compromise effective long-term monitoring. Here, we present a novel fiber-optic fluorescent nanoprobe with a high spatial resolution for label-free, subcellular pH sensing. The probe has a fast response time (~20 seconds) with minimum invasiveness and excellent pH resolution (0.02 pH units) within a biologically relevant pH environment ranging from 6.17 to 8.11. Its applicability was demonstrated on cultured A549 lung cancer cells, and its efficacy was further testified in two typical cytotoxic cases using carbonylcyanide 3-chlorophenyl hydrazine, titanium dioxide, and nanoparticles. The probe can readily detect the pH variations among cells under toxin/nanoparticles administration, enabling direct monitoring of the early onset of physiological or pathological events with high spatiotemporal resolution. This platform has excellent promise as a minimum invasive diagnostic tool for pH-related cellular mechanism studies, such as inflammation, cytotoxicity, drug resistance, carcinogenesis, stem cell differentiation and so on.
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Affiliation(s)
- Qingbo Yang
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Xiaobei Zhang
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Yang Song
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Ke Li
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Honglan Shi
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Hai Xiao
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Yinfa Ma
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
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7
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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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8
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Ward C, Meehan J, Gray ME, Murray AF, Argyle DJ, Kunkler IH, Langdon SP. The impact of tumour pH on cancer progression: strategies for clinical intervention. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2020; 1:71-100. [PMID: 36046070 PMCID: PMC9400736 DOI: 10.37349/etat.2020.00005] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
Dysregulation of cellular pH is frequent in solid tumours and provides potential opportunities for therapeutic intervention. The acidic microenvironment within a tumour can promote migration, invasion and metastasis of cancer cells through a variety of mechanisms. Pathways associated with the control of intracellular pH that are under consideration for intervention include carbonic anhydrase IX, the monocarboxylate transporters (MCT, MCT1 and MCT4), the vacuolar-type H+-ATPase proton pump, and the sodium-hydrogen exchanger 1. This review will describe progress in the development of inhibitors to these targets.
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Affiliation(s)
- Carol Ward
- Cancer Research UK Edinburgh Centre and Edinburgh Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, EH4 2XU Edinburgh, UK
| | - James Meehan
- Cancer Research UK Edinburgh Centre and Edinburgh Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, EH4 2XU Edinburgh, UK
| | - Mark E Gray
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush, EH25 9RG Midlothian, UK
| | - Alan F Murray
- School of Engineering, Institute for Integrated Micro and Nano Systems, EH9 3JL Edinburgh, UK
| | - David J Argyle
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush, EH25 9RG Midlothian, UK
| | - Ian H Kunkler
- Cancer Research UK Edinburgh Centre and Edinburgh Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, EH4 2XU Edinburgh, UK
| | - Simon P Langdon
- Cancer Research UK Edinburgh Centre and Edinburgh Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, EH4 2XU Edinburgh, UK
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9
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Na +/H + exchanger isoform 1 activity in AQP2-expressing cells can be either proliferative or anti-proliferative depending on extracellular pH. J Physiol Biochem 2019; 76:37-48. [PMID: 31811544 DOI: 10.1007/s13105-019-00713-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/06/2019] [Indexed: 10/25/2022]
Abstract
We have previously shown in renal cells that expression of the water channel Aquaporin-2 increases cell proliferation by a regulatory volume mechanism involving Na+/H+ exchanger isoform 2. Here, we investigated if Aquaporin-2 (AQP2) also modulates Na+/H+ exchanger isoform 1-dependent cell proliferation. We use two AQP2-expressing cortical collecting duct models: one constitutive (WT or AQP2-transfected RCCD1 cell line) and one inducible (control or vasopressin-induced mpkCCDc14 cell line). We found that Aquaporin-2 modifies Na+/H+ exchanger isoform 1 (NHE1) contribution to cell proliferation. In Aquaporin-2-expressing cells, Na+/H+ exchanger isoform 1 is anti-proliferative at physiological pH. In acid media, Na+/H+ exchanger isoform 1 contribution turned from anti-proliferative to proliferative only in AQP2-expressing cells. We also found that, in AQP2-expressing cells, NHE1-dependent proliferation changes parallel changes in stress fiber levels: at pH 7.4, Na+/H+ exchanger isoform 1 would favor stress fiber disassembly and, under acidosis, NHE1 would favor stress fiber assembly. Moreover, we found that Na+/H+ exchanger-dependent effects on proliferation linked to Aquaporin-2 relied on Transient Receptor Potential Subfamily V calcium channel activity. In conclusion, our data show that, in collecting duct cells, the water channel Aquaporin-2 modulates NHE1-dependent cell proliferation. In AQP2-expressing cells, at physiological pH, the Na+/H+ exchanger isoform 1 function is anti-proliferative and, at acidic pH, Na+/H+ exchanger isoform 1 function is proliferative. We propose that Na+/H+ exchanger isoform 1 modulates proliferation through an interplay with stress fiber formation.
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10
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Cabezas-Sanchez P, Rainieri S, Conlledo N, Barranco A, Sanz-Landaluze J, Camara C, Luque-Garcia JL. Impact of selenium co-administration on methylmercury exposed eleutheroembryos and adult zebrafish (Danio rerio): Changes in bioaccumulation and gene expression. CHEMOSPHERE 2019; 236:124295. [PMID: 31319311 DOI: 10.1016/j.chemosphere.2019.07.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
Mercury still represents one of the most hazardous threats for the aquatic ecosystem due to its high toxicity, and the fact that it can be easily incorporated into the food chain by accumulation in fish as MeHg. On the other hand, selenium is a micronutrient that is part of different antioxidant enzymes that regulate the cellular redox state, and whose complex interaction with Hg has been extensively studied from a toxicological point of view. In order to evaluate the protective effect of Se(IV) co-administration against MeHg accumulation and toxicity, we have selected an in-vivo model at two developmental stages: zebrafish eleutheroembryos and adult fish. Embryos were exposed during 48 h to MeHg (5 or 25 μg/l) and a concentration of Se (IV) representing a molar ratio close to one (2.5 or 12.5 μg/l), while adult zebrafish were exposed during 72 h to either 25 μg/l of MeHg alone or co-exposed with 12.5 μg/l of Se (IV). A significant decrease in MeHg bioaccumulation factor was observed in eleutheroembryos co-exposed to Se(IV). A time-dependent accumulation of MeHg was observed in all the analyzed organs and tissues of adult fish, which was significantly reduced in the muscular tissue and the intestine by Se(IV) co-administration. However, such protection against MeHg bioaccumulation was not maintained in the brain and liver. The data derived from the gene expression analysis also demonstrated the protective effect of Se(IV) against MeHg-induced oxidative stress and the activation of different defense mechanisms by Se(IV) co-administration.
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Affiliation(s)
- Pablo Cabezas-Sanchez
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Sandra Rainieri
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Nadia Conlledo
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Alejandro Barranco
- Food Research Division, AZTI, Parque Tecnológico de Bizkaia, Astondo Bidea 609, 48160, Derio, Spain
| | - Jon Sanz-Landaluze
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Carmen Camara
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain
| | - Jose L Luque-Garcia
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Ciudad Universitaria, 28040, Madrid, Spain.
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11
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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12
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Fujisaku T, Tanabe R, Onoda S, Kubota R, Segawa TF, So FTK, Ohshima T, Hamachi I, Shirakawa M, Igarashi R. pH Nanosensor Using Electronic Spins in Diamond. ACS NANO 2019; 13:11726-11732. [PMID: 31538479 DOI: 10.1021/acsnano.9b05342] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nanoscale measurements provide insight into the nano world. For instance, nanometric spatiotemporal distribution of intracellular pH is regulated by and regulates a variety of biological processes. However, there is no general method to fabricate nanoscale pH sensors. Here, we, to endow pH-sensing functions, tailor the surface properties of a fluorescent nanodiamond (FND) containing nitrogen-vacancy centers (NV centers) by coating the FND with an ionic chemical layer. The longitudinal relaxation time T1 of the electron spins in the NV centers inside a nanodiamond modified by carboxyl groups on the particle surface was found to depend on ambient pH between pH 3 and pH 7, but not between pH 7 and pH 11. Therefore, a single particle of the carboxylated nanodiamond works as a nanometer-sized pH meter within a microscopic image and directly measures the nanometric local pH environment. Moreover, the pH dependence of an FND was changed by coating it with a polycysteine layer, which contains a multitude of thiol groups with higher pKa. The polycysteine-coated nanodiamond obtained a pH dependence between pH 7 and pH 11. The pH dependence of the FND was also observed in heavy water (D2O) buffers. This indicates that the pH dependence is not caused by magnetic noise induced by 1H nuclear spin fluctuations, but by electric noise induced by ion exchanges. Via our method, the sensitive pH range of the nanodiamond pH sensor can potentially be controlled by changing the ionic layer appropriately according to the target biological phenomena.
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Affiliation(s)
- Takahiro Fujisaku
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Ryotaro Tanabe
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
| | - Shinobu Onoda
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- Takasaki Advanced Radiation Research Institute , National Institutes for Quantum and Radiological Science and Technology , 1233 Watanuki , Takasaki , Gunma 370-1292 , Japan
| | - Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Takuya F Segawa
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Laboratory for Solid State Physics , ETH Zurich , Otto-Stern-Weg 1 , 8093 Zürich , Switzerland
| | - Frederick T-K So
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Takeshi Ohshima
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- Takasaki Advanced Radiation Research Institute , National Institutes for Quantum and Radiological Science and Technology , 1233 Watanuki , Takasaki , Gunma 370-1292 , Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Masahiro Shirakawa
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Ryuji Igarashi
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- National Institute for Radiological Sciences , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- JST , PRESTO, 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan
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13
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Zhang-James Y, Vaudel M, Mjaavatten O, Berven FS, Haavik J, Faraone SV. Effect of disease-associated SLC9A9 mutations on protein-protein interaction networks: implications for molecular mechanisms for ADHD and autism. ACTA ACUST UNITED AC 2019; 11:91-105. [PMID: 30927234 DOI: 10.1007/s12402-018-0281-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/27/2018] [Indexed: 12/20/2022]
Abstract
Na+/H+ Exchanger 9 (NHE9) is an endosomal membrane protein encoded by the Solute Carrier 9A, member 9 gene (SLC9A9). SLC9A9 has been implicated in attention deficit hyperactivity disorder (ADHD), autism spectrum disorders (ASDs), epilepsy, multiple sclerosis and cancers. To better understand the function of NHE9 and the effects of disease-associated variants on protein-protein interactions, we conducted a quantitative analysis of the NHE9 interactome using co-immunoprecipitation and isobaric labeling-based quantitative mass spectrometry. We identified 100 proteins that interact with NHE9. These proteins were enriched in known functional pathways for NHE9: the endocytosis, protein ubiquitination and phagosome pathways, as well as some novel pathways including oxidative stress, mitochondrial dysfunction, mTOR signaling, cell death and RNA processing pathways. An ADHD-associated mutation (A409P) significantly altered NHE9's interactions with a subset of proteins involved in caveolae-mediated endocytosis and MAP2K2-mediated downstream signaling. An ASD nonsense mutation in SLC9A9, R423X, produced no-detectable amount of NHE9, suggesting the overall loss of NHE9 functional networks. In addition, seven of the NHE9 interactors are products of known autism candidate genes (Simons Foundation Autism Research Initiative, SFARI Gene) and 90% of the NHE9 interactome overlap with SFARI protein interaction network PIN (p < 0.0001), supporting the role of NHE9 interactome in ASDs molecular mechanisms. Our results provide a detailed understanding of the functions of protein NHE9 and its disrupted interactions, possibly underlying ADHD and ASDs. Furthermore, our methodological framework proved useful for functional characterization of disease-associated genetic variants and suggestion of druggable targets.
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Affiliation(s)
- Yanli Zhang-James
- Departments of Psychiatry, SUNY Upstate Medical University, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Marc Vaudel
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Olav Mjaavatten
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Frode S Berven
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Bergen, Norway.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Stephen V Faraone
- Departments of Psychiatry, SUNY Upstate Medical University, 750 East Adams St., Syracuse, NY, 13210, USA. .,Neuroscience and Physiology, SUNY Upstate Medical University, 750 East Adams St., Syracuse, NY, 13210, USA.
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14
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Zeng C, Vanoni S, Wu D, Caldwell JM, Wheeler JC, Arora K, Noah TK, Waggoner L, Besse JA, Yamani AN, Uddin J, Rochman M, Wen T, Chehade M, Collins MH, Mukkada VA, Putnam PE, Naren AP, Rothenberg ME, Hogan SP. Solute carrier family 9, subfamily A, member 3 (SLC9A3)/sodium-hydrogen exchanger member 3 (NHE3) dysregulation and dilated intercellular spaces in patients with eosinophilic esophagitis. J Allergy Clin Immunol 2018; 142:1843-1855. [PMID: 29729938 PMCID: PMC6448407 DOI: 10.1016/j.jaci.2018.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 03/15/2018] [Accepted: 03/26/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Eosinophilic esophagitis (EoE) is characterized by histopathologic modifications of esophageal tissue, including eosinophil-rich inflammation, basal zone hyperplasia, and dilated intercellular spaces (DIS). The underlying molecular processes that drive the histopathologic features of EoE remain largely unexplored. OBJECTIVE We sought to investigate the involvement of solute carrier family 9, subfamily A, member 3 (SLC9A3) in esophageal epithelial intracellular pH (pHi) and DIS formation and the histopathologic features of EoE. METHODS We examined expression of esophageal epithelial gene networks associated with regulation of pHi in the EoE transcriptome of primary esophageal epithelial cells and an in vitro esophageal epithelial 3-dimensional model system (EPC2-ALI). Molecular and cellular analyses and ion transport assays were used to evaluate the expression and function of SLC9A3. RESULTS We identified altered expression of gene networks associated with regulation of pHi and acid-protective mechanisms in esophageal biopsy specimens from pediatric patients with EoE (healthy subjects, n = 6; patients with EoE, n = 10). The most dysregulated gene central to regulating pHi was SLC9A3. SLC9A3 expression was increased within the basal layer of esophageal biopsy specimens from patients with EoE, and expression positively correlated with disease severity (eosinophils/high-power field) and DIS (healthy subjects, n = 10; patients with EoE, n = 10). Analyses of esophageal epithelial cells revealed IL-13-induced, signal transducer and activator of transcription 6-dependent SLC9A3 expression and Na+-dependent proton secretion and that SLC9A3 activity correlated positively with DIS formation. Finally, we showed that IL-13-mediated, Na+-dependent proton secretion was the primary intracellular acid-protective mechanism within the esophageal epithelium and that blockade of SLC9A3 transport abrogated IL-13-induced DIS formation. CONCLUSIONS SLC9A3 plays a functional role in DIS formation, and pharmacologic interventions targeting SLC9A3 function may suppress the histopathologic manifestations in patients with EoE.
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Affiliation(s)
- Chang Zeng
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Simone Vanoni
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - David Wu
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Julie M Caldwell
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Justin C Wheeler
- Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Kavisha Arora
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Taeko K Noah
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Lisa Waggoner
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - John A Besse
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Amnah N Yamani
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Jazib Uddin
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Mark Rochman
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ting Wen
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Mirna Chehade
- Mount Sinai Center for Eosinophilic Disorders, Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Margaret H Collins
- Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Vincent A Mukkada
- Division of Gastroenterology, Nutrition and Hepatology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Philip E Putnam
- Division of Gastroenterology, Nutrition and Hepatology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Marc E Rothenberg
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Simon P Hogan
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pathology, Mary H Weiser Food Allergy Center, Michigan Medicine, University of Michigan, Ann Arbor, Mich.
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15
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Zhang HM, Liu MY, Lu JX, Zhu ML, Jin Q, Ping S, Li P, Jian X, Han YL, Wang SX, Li XY. Intracellular acidosis via activation of Akt-Girdin signaling promotes post ischemic angiogenesis during hyperglycemia. Int J Cardiol 2018; 277:205-211. [PMID: 30316647 DOI: 10.1016/j.ijcard.2018.08.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 08/07/2018] [Accepted: 08/09/2018] [Indexed: 10/28/2022]
Abstract
AIMS The impaired angiogenesis is the major cause of diabetic delayed wound healing. The molecular insight remains unknown. Previous study has shown that high glucose (HG) activates Na+/H+ exchanger 1 (NHE1) and induces intracellular alkalinization, resulting in endothelial dysfunction. The aim of this study is to investigate whether activation of NHE1 in endothelial cells by HG damages the angiogenesis in vitro and in vivo. METHODS AND RESULTS We used western blot to detect the phosphorylations of both Akt and Girdin, and pH-sensitive BCECF fluorescence to assay NHE1 activity and pHi value, respectively. The angiogenesis was evaluated by measuring the number of tube formation in vitro, and blood perfusion by laser doppler and neovascularization by staining CD31 in vivo. Our results indicated that induction of intracellular acidosis (IA) increased p-Akt and p-Girdin in human umbilical vein endothelial cells (HUVEC). HG activated NHE1 and increased pHi value in a time-dependent manner, associated with the decreased phosphorylations of both Akt and Gridin, while inhibition of NHE1 by amiloride abolished the HG-induced reductions of p-Akt and p-Girdin. However, silence of Akt by siRNA transfection or pharmacological inhibitors (wortmannin and LY294002) bypassed IA-induced Girdin phosphorylation. Overexpression of constitutively active Akt abolished HG-reduced Girdin phosphorylation. In addition, upregulation of Akt or inhibition of NHE1 remarkably attenuated HG-impaired tube formation in HUVEC. In vivo study revealed that amiloride dramatically rescued hyperglycemia-delayed blood perfusion and neovascularization by augmenting ischemia-induced angiogenesis. CONCLUSION IA promotes ischemia-induced angiogenesis via Akt-dependent Girdin phosphorylation in diabetic mice.
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Affiliation(s)
- Hong-Ming Zhang
- Department of Cardiology, General Hospital of Jinan Military Command, Jinan, China
| | - Mo-Yan Liu
- Department of Cardiology, General Hospital of Jinan Military Command, Jinan, China
| | - Jun-Xiu Lu
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Mo-Li Zhu
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Qun Jin
- Department of Cardiology, General Hospital of Jinan Military Command, Jinan, China
| | - Song Ping
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Peng Li
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Xu Jian
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Ya-Ling Han
- Department of Cardiology, General Hospital of Shenyang Military Command, Shenyang, China.
| | - Shuang-Xi Wang
- Department of Pharmacology, College of Pharmacy, Xinxiang Medical University, Xinxiang, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China.
| | - Xiao-Yan Li
- Department of Cardiology, General Hospital of Jinan Military Command, Jinan, China.
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16
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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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17
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Bhattarai KR, Lee HY, Kim SH, Kim HR, Chae HJ. Ixeris dentata Extract Increases Salivary Secretion through the Regulation of Endoplasmic Reticulum Stress in a Diabetes-Induced Xerostomia Rat Model. Int J Mol Sci 2018; 19:ijms19041059. [PMID: 29614832 PMCID: PMC5979381 DOI: 10.3390/ijms19041059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 03/20/2018] [Accepted: 03/28/2018] [Indexed: 12/14/2022] Open
Abstract
This study aimed to investigate the molecular mechanism of diabetes mellitus (DM)-induced dry mouth and an application of natural products from Ixeris dentata (IXD), a recently suggested regulator of amylase secretion in salivary cells. Vehicle-treated or diabetic rats were orally treated with either water or an IXD extract for 10 days to observe the effect on salivary flow. We found that the IXD extract increased aquaporin 5 (AQP5) and alpha-amylase protein expression in the submandibular gland along with salivary flow rate. Similarly, the IXD extract and its purified compound increased amylase secretion in high glucose-exposed human salivary gland cells. Furthermore, increased endoplasmic reticulum stress response in the submandibular gland of diabetic rats was inhibited by treatment with the IXD extract, suggesting that IXD extract treatment improves the ER environment by increasing the protein folding capacity. Thus, pharmacological treatment with the IXD extract is suggested to relieve DM-induced dry mouth symptoms.
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Affiliation(s)
- Kashi Raj Bhattarai
- Department of Pharmacology and Institute of New Drug Development, School of Medicine, Chonbuk National University, Jeonju 54896, Korea.
| | - Hwa-Young Lee
- Department of Pharmacology and Institute of New Drug Development, School of Medicine, Chonbuk National University, Jeonju 54896, Korea.
| | - Seung-Hyun Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Science, Yonsei University, Incheon 406-840, Korea.
| | - Hyung-Ryong Kim
- Graduate School, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea.
| | - Han-Jung Chae
- Department of Pharmacology and Institute of New Drug Development, School of Medicine, Chonbuk National University, Jeonju 54896, Korea.
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18
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Packer M. Role of the sodium-hydrogen exchanger in mediating the renal effects of drugs commonly used in the treatment of type 2 diabetes. Diabetes Obes Metab 2018; 20:800-811. [PMID: 29227582 DOI: 10.1111/dom.13191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 01/19/2023]
Abstract
Diabetes is characterized by increased activity of the sodium-hydrogen exchanger (NHE) in the glomerulus and renal tubules, which contributes importantly to the development of nephropathy. Despite the established role played by the exchanger in experimental studies, it has not been specifically targeted by those seeking to develop novel pharmacological treatments for diabetes. This review demonstrates that many existing drugs that are commonly prescribed to patients with diabetes act on the NHE1 and NHE3 isoforms in the kidney. This action may explain their effects on sodium excretion, albuminuria and the progressive decline of glomerular function in clinical trials; these responses cannot be readily explained by the influence of these drugs on blood glucose. Agents that may affect the kidney in diabetes by virtue of an action on NHE include: (1) insulin and insulin sensitizers; (2) incretin-based agents; (3) sodium-glucose cotransporter 2 inhibitors; (4) antagonists of the renin-angiotensin system (angiotensin converting-enzyme inhibitors, angiotensin receptor blockers and angiotensin receptor neprilysin inhibitors); and (5) inhibitors of aldosterone action and cholesterol synthesis (spironolactone, amiloride and statins). The renal effects of each of these drug classes in patients with type 2 diabetes may be related to a single shared biological mechanism.
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Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas
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19
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Xu H, Ghishan FK, Kiela PR. SLC9 Gene Family: Function, Expression, and Regulation. Compr Physiol 2018; 8:555-583. [PMID: 29687889 DOI: 10.1002/cphy.c170027] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Slc9 family of Na+ /H+ exchangers (NHEs) plays a critical role in electroneutral exchange of Na+ and H+ in the mammalian intestine as well as other absorptive and secretory epithelia of digestive organs. These transport proteins contribute to the transepithelial Na+ and water absorption, intracellular pH and cellular volume regulation as well as the electrolyte, acid-base, and fluid volume homeostasis at the systemic level. They also influence the function of other membrane transport mechanisms, affect cellular proliferation and apoptosis as well as cell migration, adherence to the extracellular matrix, and tissue repair. Additionally, they modulate the extracellular milieu to facilitate other nutrient absorption and to regulate the intestinal microbial microenvironment. Na+ /H+ exchange is inhibited in selected gastrointestinal diseases, either by intrinsic factors (e.g., bile acids, inflammatory mediators) or infectious agents and associated bacterial toxins. Disrupted NHE activity may contribute not only to local and systemic electrolyte imbalance but also to the disease severity via multiple mechanisms. In this review, we describe the cation proton antiporter superfamily of Na+ /H+ exchangers with a particular emphasis on the eight SLC9A isoforms found in the digestive tract, followed by a more integrative description in their roles in each of the digestive organs. We discuss regulatory mechanisms that determine the function of Na+ /H+ exchangers as pertinent to the digestive tract, their regulation in pathological states of the digestive organs, and reciprocally, the contribution of dysregulated Na+ /H+ exchange to the disease pathogenesis and progression. © 2018 American Physiological Society. Compr Physiol 8:555-583, 2018.
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Affiliation(s)
- Hua Xu
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA
| | - Fayez K Ghishan
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA
| | - Pawel R Kiela
- Department of Pediatrics, Steele Children's Research Center, University of Arizona, Tucson, Arizona, USA.,Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
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20
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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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Singh AK, Singh S, Garg G, Rizvi SI. Rapamycin mitigates erythrocyte membrane transport functions and oxidative stress during aging in rats. Arch Physiol Biochem 2018; 124:45-53. [PMID: 28758804 DOI: 10.1080/13813455.2017.1359629] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Erythrocyte membrane is a suitable model to study various metabolic and physiological functions as it undergoes variety of biochemical changes during aging. An age-dependent modulatory effect of rapamycin on erythrocyte membrane functions is completely unknown. Therefore, the present study was undertaken to investigate the effect of rapamycin on age-dependent impaired activities of transporters/exchangers, altered levels of redox biomarkers, viz. protein carbonyl (PC), lipid hydroperoxides (LHs), total thiol (-SH), sialic acid (SA) and intracellular calcium ion [Ca2+]i, and osmotic fragility of erythrocyte membrane. A significant reduction in membrane-bound activities of Na+/K+-ATPase (NKA) and Ca2+-ATPase (PMCA), and levels of -SH and SA was observed along with a simultaneous induction in Na+/H+ exchanger (NHE) activity and levels of [Ca2+]i, PC, LH and osmotic fragility in old-aged rats. Rapamycin was found to be a promising age-delaying drug that significantly reversed the aging-induced impaired activities of membrane-bound ATPases and altered levels of redox biomarkers.
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Affiliation(s)
| | - Sandeep Singh
- a Department of Biochemistry , University of Allahabad , Allahabad , India
| | - Geetika Garg
- a Department of Biochemistry , University of Allahabad , Allahabad , India
| | - Syed Ibrahim Rizvi
- a Department of Biochemistry , University of Allahabad , Allahabad , India
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22
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Packer M. Activation and Inhibition of Sodium-Hydrogen Exchanger Is a Mechanism That Links the Pathophysiology and Treatment of Diabetes Mellitus With That of Heart Failure. Circulation 2017; 136:1548-1559. [PMID: 29038209 DOI: 10.1161/circulationaha.117.030418] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The mechanisms underlying the progression of diabetes mellitus and heart failure are closely intertwined, such that worsening of one condition is frequently accompanied by worsening of the other; the degree of clinical acceleration is marked when the 2 coexist. Activation of the sodium-hydrogen exchanger in the heart and vasculature (NHE1 isoform) and the kidneys (NHE3 isoform) may serve as a common mechanism that links both disorders and may underlie their interplay. Insulin insensitivity and adipokine abnormalities (the hallmarks of type 2 diabetes mellitus) are characteristic features of heart failure; conversely, neurohormonal systems activated in heart failure (norepinephrine, angiotensin II, aldosterone, and neprilysin) impair insulin sensitivity and contribute to microvascular disease in diabetes mellitus. Each of these neurohormonal derangements may act through increased activity of both NHE1 and NHE3. Drugs used to treat diabetes mellitus may favorably affect the pathophysiological mechanisms of heart failure by inhibiting either or both NHE isoforms, and drugs used to treat heart failure may have beneficial effects on glucose tolerance and the complications of diabetes mellitus by interfering with the actions of NHE1 and NHE3. The efficacy of NHE inhibitors on the risk of cardiovascular events may be enhanced when heart failure and glucose intolerance coexist and may be attenuated when drugs with NHE inhibitory actions are given concomitantly. Therefore, the sodium-hydrogen exchanger may play a central role in the interplay of diabetes mellitus and heart failure, contribute to the physiological and clinical progression of both diseases, and explain certain drug-drug and drug-disease interactions that have been reported in large-scale randomized clinical trials.
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Affiliation(s)
- Milton Packer
- From Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, TX.
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23
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Fernández-Morales JC, Morad M. Regulation of Ca 2+ signaling by acute hypoxia and acidosis in rat neonatal cardiomyocytes. J Mol Cell Cardiol 2017; 114:58-71. [PMID: 29032102 DOI: 10.1016/j.yjmcc.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/20/2017] [Accepted: 10/08/2017] [Indexed: 11/25/2022]
Abstract
Ischemic heart disease is an arrhythmogenic condition, accompanied by hypoxia, acidosis, and impaired Ca2+ signaling. Here we report on effects of acute hypoxia and acidification in rat neonatal cardiomyocytes cultures. RESULTS Two populations of neonatal cardiomyocyte were identified based on inactivation kinetics of L-type ICa: rapidly-inactivating ICa (τ~20ms) myocytes (prevalent in 3-4-day cultures), and slow-inactivating ICa (τ≥40ms) myocytes (dominant in 7-day cultures). Acute hypoxia (pO2<5mmHg for 50-100s) suppressed ICa reversibly in both cell-types to different extent and with different kinetics. This disparity disappeared when Ba2+ was the channel charge carrier, or when the intracellular Ca2+ buffering capacity was increased by dialysis of high concentrations of EGTA and BAPTA, suggesting critical role for calcium-dependent inactivation. Suppressive effect of acute acidosis on ICa (~40%, pH6.7), on the other hand, was not cell-type dependent. Isoproterenol enhanced ICa in both cell-types, but protected only against suppressive effects of acidosis and not hypoxia. Hypoxia and acidosis suppressed global Ca2+ transients by ~20%, but suppression was larger, ~35%, at the RyR2 microdomains, using GCaMP6-FKBP targeted probe. Hypoxia and acidosis also suppressed mitochondrial Ca2+ uptake by 40% and 10%, respectively, using mitochondrial targeted Ca2+ biosensor (mito-GCaMP6). CONCLUSION Our studies suggest that acute hypoxia suppresses ICa in rapidly inactivating cell population by a mechanism involving Ca2+-dependent inactivation, while compromised mitochondrial Ca2+ uptake seems also to contribute to ICa suppression in slowly inactivating cell population. Proximity of cellular Ca2+ pools to sarcolemmal Ca2+ channels may contribute to the variability of inactivation kinetics of ICa in the two cell populations, while acidosis suppression of ICa appears mediated by proton-induced block of the calcium channel.
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Affiliation(s)
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA; Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA.
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Hardonnière K, Huc L, Sergent O, Holme JA, Lagadic-Gossmann D. Environmental carcinogenesis and pH homeostasis: Not only a matter of dysregulated metabolism. Semin Cancer Biol 2017; 43:49-65. [PMID: 28088583 DOI: 10.1016/j.semcancer.2017.01.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/18/2022]
Abstract
According to the World Health Organization, around 20% of all cancers would be due to environmental factors. Among these factors, several chemicals are indeed well recognized carcinogens. The widespread contaminant benzo[a]pyrene (B[a]P), an often used model carcinogen of the polycyclic aromatic hydrocarbons' family, has been suggested to target most, if not all, cancer hallmarks described by Hanahan and Weinberg. It is classified as a group I carcinogen by the International Agency for Research on Cancer; however, the precise intracellular mechanisms underlying its carcinogenic properties remain yet to be thoroughly defined. Recently, the pH homeostasis, a well known regulator of carcinogenic processes, was suggested to be a key actor in both cell death and Warburg-like metabolic reprogramming induced upon B[a]P exposure. The present review will highlight those data with the aim of favoring research on the role of H+ dynamics in environmental carcinogenesis.
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Affiliation(s)
- Kévin Hardonnière
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France
| | - Laurence Huc
- INRA UMR 1331 ToxAlim (Research Center in Food Toxicology), University of Toulouse ENVT, INP, UPS, 180 Chemin de Tournefeuille, F-31027, France
| | - Odile Sergent
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France
| | - Jørn A Holme
- Domain of Infection Control, Environment and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Dominique Lagadic-Gossmann
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France.
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25
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Sergeeva TF, Shirmanova MV, Zlobovskaya OA, Gavrina AI, Dudenkova VV, Lukina MM, Lukyanov KA, Zagaynova EV. Relationship between intracellular pH, metabolic co-factors and caspase-3 activation in cancer cells during apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:604-611. [PMID: 28063999 DOI: 10.1016/j.bbamcr.2016.12.022] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 12/21/2022]
Abstract
A complex cascade of molecular events occurs in apoptotic cells but cell-to-cell variability significantly complicates determination of the order and interconnections between different processes. For better understanding of the mechanisms of programmed cell death, dynamic simultaneous registration of several parameters is required. In this paper we used multiparameter fluorescence microscopy to analyze energy metabolism, intracellular pH and caspase-3 activation in living cancer cells in vitro during staurosporine-induced apoptosis. We performed metabolic imaging of two co-factors, NAD(P)H and FAD, and used the genetically encoded pH-indicator SypHer1 and the FRET-based sensor for caspase-3 activity, mKate2-DEVD-iRFP, to visualize these parameters by confocal fluorescence microscopy and two-photon fluorescence lifetime imaging microscopy. The correlation between energy metabolism, intracellular pH and caspase-3 activation and their dynamic changes were studied in CT26 cancer cells during apoptosis. Induction of apoptosis was accompanied by a switch to oxidative phosphorylation, cytosol acidification and caspase-3 activation. We showed that alterations in cytosolic pH and the activation of oxidative phosphorylation are relatively early events associated with the induction of apoptosis.
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Affiliation(s)
- Tatiana F Sergeeva
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia.
| | - Marina V Shirmanova
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia.
| | - Olga A Zlobovskaya
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 16/10 Miklukho-Maklaya St., 117997 Moscow, Russia.
| | - Alena I Gavrina
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia; Nizhny Novgorod State University, Gagarin Ave., 23, 603950 Nizhny Novgorod, Russia.
| | - Varvara V Dudenkova
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia; Nizhny Novgorod State University, Gagarin Ave., 23, 603950 Nizhny Novgorod, Russia.
| | - Maria M Lukina
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia; Nizhny Novgorod State University, Gagarin Ave., 23, 603950 Nizhny Novgorod, Russia.
| | - Konstantin A Lukyanov
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 16/10 Miklukho-Maklaya St., 117997 Moscow, Russia.
| | - Elena V Zagaynova
- Nizhny Novgorod State Medical Academy, 10/1 Minin and Pozharsky Sq., 603005 Nizhny Novgorod, Russia.
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Wu Y, Zhang M, Liu R, Zhao C. Oxidative Stress-Activated NHE1 Is Involved in High Glucose-Induced Apoptosis in Renal Tubular Epithelial Cells. Yonsei Med J 2016; 57:1252-9. [PMID: 27401659 PMCID: PMC4960394 DOI: 10.3349/ymj.2016.57.5.1252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/14/2016] [Accepted: 02/17/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Diabetic nephropathy (DN) is a prevalent chronic microvascular complication of diabetes mellitus involving disturbances in electrolytes and the acid-base balance caused by a disorder of glucose metabolism. NHE1 is a Na⁺/H⁺ exchanger responsible for keeping intracellular pH (pHi) balance and cell growth. Our study aimed to investigate roles of NHE1 in high glucose (HG)-induced apoptosis in renal tubular epithelial cells. MATERIALS AND METHODS Renal epithelial tubular cell line HK-2 was cultured in medium containing 5 mM or 30 mM glucose. Then, cell apoptosis, oxidative stress, NHE1 expression, and pHi were evaluated. NHE1 siRNA and inhibitor were used to evaluate its role in cell apoptosis. RESULTS HG significantly increased cell apoptosis and the production of reactive oxygen species (ROS) and 8-OHdG (p<0.05). Meanwhile, we found that HG induced the expression of NHE1 and increased the pHi from 7.0 to 7.6 after 48 h of incubation. However, inhibiting NHE1 using its specific siRNA or antagonist DMA markedly reduced cell apoptosis stimulated by HG. In addition, suppressing cellular oxidative stress using antioxidants, such as glutathione and N-acetyl cysteine, significantly reduced the production of ROS, accompanied by a decrease in NHE1. We also found that activated cyclic GMP-Dependent Protein Kinase Type I (PKG) signaling promoted the production of ROS, which contributed to the regulation of NHE1 functions. CONCLUSION Our study indicated that HG activates PKG signaling and elevates the production of ROS, which was responsible for the induction of NHE1 expression and dysfunction, as well as subsequent cell apoptosis, in renal tubular epithelial cells.
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Affiliation(s)
- Yiqing Wu
- Department of Nephrology, Tianjin Union Medicine Center, Tianjin, China
| | - Min Zhang
- Department of Nephrology, Tianjin Union Medicine Center, Tianjin, China
| | - Rui Liu
- Department of Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Chunjie Zhao
- Department of Cardiology, Tianjin Union Medicine Center, Tianjin, China.
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Alterations in Red Blood Cell Functionality Induced by an Indole Scaffold Containing a Y-Iminodiketo Moiety: Potential Antiproliferative Conditions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:2104247. [PMID: 27651854 PMCID: PMC5019890 DOI: 10.1155/2016/2104247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/06/2016] [Accepted: 07/11/2016] [Indexed: 02/04/2023]
Abstract
We have recently proposed a new erythrocyte-based model of study to predict the antiproliferative effects of selected heterocyclic scaffolds. Starting from the metabolic similarity between erythrocytes and cancer cells, we have demonstrated how the metabolic derangement induced by an indolone-based compound (DPIT) could be related to its antiproliferative effects. In order to prove the validity of our biochemical approach, in the present study the effects on erythrocyte functionality of its chemical precursor (PID), whose synthesis we reported, were investigated. The influence of the tested compound on band 3 protein (B3), oxidative state, ATP efflux, caspase 3, metabolism, intracellular pH, and Ca2+ homeostasis has been evaluated. PID crosses the membrane localizing into the cytosol, increases anion exchange, induces direct caspase activation, shifts the erythrocytes towards an oxidative state, and releases less ATP than in normal conditions. Analysis of phosphatidylserine externalization shows that PID slightly induces apoptosis. Our findings indicate that, due to its unique features, erythrocyte responses to exogenous molecular stimuli can be fruitfully correlated at structurally more complex cells, such as cancer cells. Overall, our work indicates that erythrocyte is a powerful study tool to elucidate the biochemical/biological effects of selected heterocycles opening considerable perspectives in the field of drug discovery.
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Chien EJ, Hsu CH, Chang VHJ, Lin EPY, Kuo TPT, Chien CH, Lin HY. In human T cells mifepristone antagonizes glucocorticoid non-genomic rapid responses in terms of Na(+)/H(+)-exchange 1 activity, but not ezrin/radixin/moesin phosphorylation. Steroids 2016; 111:29-36. [PMID: 26773750 DOI: 10.1016/j.steroids.2016.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 01/01/2023]
Abstract
Glucocorticoids (GCs) and progesterone have been employed as immunosuppressive agents during pregnancy for many years. Intracellular acidification by GCs is due to a rapid non-genomic inhibition of membrane Na(+)/H(+)-exchange 1 (NHE1) activity and is followed by immunosuppression of PHA-stimulated proliferation. NHE1 is tethered to the cortical actin cytoskeleton through ezrin/radixin/moesin (ERM) proteins within lipid rafts; these regulate cell shape, migration and resistance to apoptosis. We explored whether mifepristone (RU486), an antagonist of GCs in T cells, is able to completely block rapid non-genomic responses, namely NHE1 activity and the phosphorylation C-terminal residues of ERM proteins at threonine (cp-ERM). GCs stimulate a rapid non-genomic cp-ERM response in cells within 5min. RU486 antagonized the GC-induced rapid decrease in NHE1 activity, and arrested PHA-stimulated T cells at G0/G1 phase but had no effect on the rapid increase in cp-ERM, which persisted for 24h. However, the cp-ERM response was blocked by staurosporine in both resting and GC stimulated cells. The results of RU486 antagonized the GC induced rapid decrease in NHE1 ion transport activity, but not the increase cp-ERM. This suggests that RU486 in T cells exerts its antagonistic effects at NHE1 containing plasma membrane sites and not where cp-ERM links lipid rafts to cortical cytoskeletons.
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Affiliation(s)
- Eileen Jea Chien
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC; Department of Healthcare Administration, Asia University, Taichung 41354, Taiwan, ROC; Graduate Institute of Basic Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan, ROC.
| | - Ching-Hui Hsu
- Division of Allergy-Immunology-Rheumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Vincent Han-Jhih Chang
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Enoch Pin-Yi Lin
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Trista Pin-Tsun Kuo
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Chau-Heng Chien
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Hsiao-Yi Lin
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC; Division of Allergy-Immunology-Rheumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC.
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29
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Chen CH, Chen TH, Wu MY, Chen JR, Hong LY, Zheng CM, Chiu IJ, Lin YF, Hsu YH. Peroxisome Proliferator-Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na +/H + Exchanger NHE1. Mol Med 2015; 21:886-889. [PMID: 26623927 DOI: 10.2119/molmed.2015.00196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/23/2015] [Indexed: 12/18/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na+/H+ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na+/H+ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin.
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Affiliation(s)
- Cheng-Hsien Chen
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Tso-Hsiao Chen
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Mei-Yi Wu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Jia-Rung Chen
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Li-Yu Hong
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Cai-Mei Zheng
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - I-Jen Chiu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yuh-Feng Lin
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yung-Ho Hsu
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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30
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Mohamed IA, Mraiche F. Targeting osteopontin, the silent partner of Na+/H+ exchanger isoform 1 in cardiac remodeling. J Cell Physiol 2015; 230:2006-18. [PMID: 25677682 DOI: 10.1002/jcp.24958] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 02/06/2015] [Indexed: 12/11/2022]
Abstract
Cardiac hypertrophy (CH), characterized by the enlargement of cardiomyocytes, fibrosis and apoptosis, contributes to cardiac remodeling, which if left unresolved results in heart failure. Understanding the signaling pathways underlying CH is necessary to identify potential therapeutic targets. The Na(+) /H(+) -exchanger isoform I (NHE1), a ubiquitously expressed glycoprotein and cardiac specific isoform, regulates intracellular pH. Recent studies have demonstrated that enhanced expression/activity of NHE1 contributes to cardiac remodeling and CH. Inhibition of NHE1 in both in vitro and in vivo models have suggested that inhibition of NHE1 protects against hypertrophy. However, clinical trials using NHE1 inhibitors have proven to be unsuccessful, suggesting that additional factors maybe contributing to cardiac remodeling. Recent studies have indicated that the upregulation of NHE1 is associated with enhanced levels of osteopontin (OPN) in the setting of CH. OPN has been demonstrated to be upregulated in left ventricular hypertrophy, dilated cardiomyopathy and in diabetic cardiomyopathy. The cellular interplay between OPN and NHE1 in the setting of CH remains unknown. This review focuses on the role of NHE1 and OPN in cardiac remodeling and emphasizes the signaling pathways implicating OPN in the NHE1-induced hypertrophic response.
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31
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Park SY, Lee YJ, Cho EJ, Shin CY, Sohn UD. Intrinsic resistance triggered under acid loading within normal esophageal epithelial cells: NHE1- and ROS-mediated survival. J Cell Physiol 2015; 230:1503-14. [DOI: 10.1002/jcp.24896] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 12/12/2014] [Indexed: 01/27/2023]
Affiliation(s)
- Sun Young Park
- Department of Pharmacology; College of Pharmacy; Chung-Ang University; Seoul South Korea
| | - Yeon Joo Lee
- Department of Pharmacology; College of Pharmacy; Chung-Ang University; Seoul South Korea
| | - Eun Jeong Cho
- Department of Pharmacology; College of Pharmacy; Chung-Ang University; Seoul South Korea
| | - Chang Yell Shin
- Dong-A Pharmaceutical; Research Center; Yongin-si Gyeonggi-do South Korea
| | - Uy Dong Sohn
- Department of Pharmacology; College of Pharmacy; Chung-Ang University; Seoul South Korea
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32
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Na+-H+ exchanger-1 (NHE1) regulation in kidney proximal tubule. Cell Mol Life Sci 2015; 72:2061-74. [PMID: 25680790 DOI: 10.1007/s00018-015-1848-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 01/17/2023]
Abstract
The ubiquitously expressed plasma membrane Na(+)-H(+) exchanger NHE1 is a 12 transmembrane-spanning protein that directs important cell functions such as homeostatic intracellular volume and pH control. The 315 amino acid cytosolic tail of NHE1 binds plasma membrane phospholipids and multiple proteins that regulate additional, ion-translocation independent functions. This review focuses on NHE1 structure/function relationships, as well as the role of NHE1 in kidney proximal tubule functions, including pH regulation, vectorial Na(+) transport, cell volume control and cell survival. The implications of these functions are particularly critical in the setting of progressive, albuminuric kidney diseases, where the accumulation of reabsorbed fatty acids leads to disruption of NHE1-membrane phospholipid interactions and tubular atrophy, which is a poor prognostic factor for progression to end stage renal disease. This review amplifies the vital role of the proximal tubule NHE1 Na(+)-H(+) exchanger as a kidney cell survival factor.
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33
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Wiese H, Gelis L, Wiese S, Reichenbach C, Jovancevic N, Osterloh M, Meyer HE, Neuhaus EM, Hatt HH, Radziwill G, Warscheid B. Quantitative phosphoproteomics reveals the protein tyrosine kinase Pyk2 as a central effector of olfactory receptor signaling in prostate cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1854:632-40. [PMID: 25219547 DOI: 10.1016/j.bbapap.2014.09.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/21/2014] [Accepted: 09/02/2014] [Indexed: 10/24/2022]
Abstract
The prostate-specific G-protein-coupled receptor 1 (PSGR1) is an olfactory receptor specifically expressed in the prostate gland. PSGR1 expression is elevated both in benign prostatic hyperplasia tissue and in prostate cancer. Stimulation of PSGR1 by the odorant β-ionone leads to an increase in the intracellular Ca(2+) concentration, activation of mitogen-activated protein (MAP) kinases and a decrease in prostate cancer cell proliferation. To further extend our knowledge about PSGR1 signaling in prostate cancer cells, we performed a quantitative phosphoproteomics study using stable isotope labeling by amino acids in cell culture and mass spectrometry. We report 51 differentially regulated phosphorylation sites in 24 proteins with functions in cytoskeletal remodeling, signaling and ion transport. Activation of PSGR1 evoked an increase in intracellular pH mediated by the sodium/hydrogen exchanger NHE1. Furthermore, we report the protein tyrosine kinase Pyk2 as a central effector of PSGR1 signaling cascades in LNCaP cells. Our data show that phosphorylation of p38 MAP kinase is triggered by Pyk2. In addition, we confirmed dephosphorylation of the tumor suppressor protein N-myc downstream regulated gene 1 (NDRG1) at Ser330 downstream of Pyk2. Since NDRG1 impacts oncogenic signaling pathways interfering with tumor progression, we suggest that the Pyk2-NDRG1 axis is possibly involved in conveying the anti-proliferative effect of β-ionone in prostate cancer cells. This article is part of a Special Issue entitled: Medical Proteomics.
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Affiliation(s)
- Heike Wiese
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Lian Gelis
- Department of Cell Physiology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Sebastian Wiese
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Christa Reichenbach
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Nikolina Jovancevic
- Department of Cell Physiology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Markus Osterloh
- Department of Cell Physiology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Helmut E Meyer
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Eva M Neuhaus
- Department of Pharmacology and Toxicology, University of Jena, Drackendorfer Str. 1, 07747 Jena, Germany
| | - Hanns H Hatt
- Department of Cell Physiology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Gerald Radziwill
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
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Sigurðsson HH, Olesen CW, Dybboe R, Lauritzen G, Pedersen SF. Constitutively active ErbB2 regulates cisplatin-induced cell death in breast cancer cells via pro- and antiapoptotic mechanisms. Mol Cancer Res 2014; 13:63-77. [PMID: 25143433 DOI: 10.1158/1541-7786.mcr-14-0011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Despite the frequent expression of N-terminally truncated ErbB2 (ΔNErbB2/p95HER2) in breast cancer and its association with Herceptin resistance and poor prognosis, it remains poorly understood how ΔNErbB2 affects chemotherapy-induced cell death. Previously it was shown that ΔNErbB2 upregulates acid extrusion from MCF-7 breast cancer cells and that inhibition of the Na(+)/H(+) exchanger (SLC9A1/NHE1) strongly sensitizes ΔNErbB2-expressing MCF-7 cells to cisplatin chemotherapy. The aim of this study was to identify the mechanism through which ΔNErbB2 regulates cisplatin-induced breast cancer cell death, and determine how NHE1 regulates this process. Cisplatin treatment elicited apoptosis, ATM phosphorylation, upregulation of p53, Noxa (PMAIP1), and PUMA (BBC3), and cleavage of caspase-9, -7, fodrin, and PARP-1 in MCF-7 cells. Inducible ΔNErbB2 expression strongly reduced cisplatin-induced ATM- and p53-phosphorylation, augmented Noxa upregulation and caspase-9 and -7 cleavage, doubled p21(WAF1/Cip1) (CDKN1A) expression, and nearly abolished Bcl-2 expression. LC3-GFP analysis demonstrated that autophagic flux was reduced by cisplatin in a manner augmented by ΔNErbB2, yet did not contribute to cisplatin-induced death. Using knockdown approaches, it was shown that cisplatin-induced caspase-7 cleavage in ΔNErbB2-MCF-7 cells was Noxa- and caspase-9 dependent. This pathway was augmented by NHE1 inhibition, while the Na(+)/HCO3 (-) cotransporter (SLC4A7/NBCn1) was internalized following cisplatin exposure. IMPLICATIONS This work reveals that ΔNErbB2 strongly affects several major pro- and antiapoptotic pathways and provides mechanistic insight into the role of NHE1 in chemotherapy resistance. These findings have relevance for defining therapy regimens in breast cancers with ΔNErbB2 and/or NHE1 overexpression.
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Affiliation(s)
- Haraldur H Sigurðsson
- Department of Biology, Section for Cell and Developmental Biology, University of Copenhagen, Copenhagen, Denmark
| | - Christina W Olesen
- Department of Biology, Section for Cell and Developmental Biology, University of Copenhagen, Copenhagen, Denmark
| | - Rie Dybboe
- Department of Biology, Section for Cell and Developmental Biology, University of Copenhagen, Copenhagen, Denmark
| | - Gitte Lauritzen
- Department of Biology, Section for Cell and Developmental Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stine F Pedersen
- Department of Biology, Section for Cell and Developmental Biology, University of Copenhagen, Copenhagen, Denmark.
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Coaxum SD, Blanton MG, Joyner A, Akter T, Bell PD, Luttrell LM, Raymond JR, Lee MH, Blichmann PA, Garnovskaya MN, Saigusa T. Epidermal growth factor-induced proliferation of collecting duct cells from Oak Ridge polycystic kidney mice involves activation of Na+/H+ exchanger. Am J Physiol Cell Physiol 2014; 307:C554-60. [PMID: 25055824 DOI: 10.1152/ajpcell.00188.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Epidermal growth factor (EGF) is linked to the pathogenesis of polycystic kidney disease (PKD). We explored signaling pathways activated by EGF in orpk cilia (-) collecting duct cell line derived from a mouse model of PKD (hypomorph of the Tg737/Ift88 gene) with severely stunted cilia, and in a control orpk cilia (+) cell line with normal cilia. RT-PCR demonstrated mRNAs for EGF receptor subunits ErbB1, ErbB2, ErbB3, ErbB4, and mRNAs for Na(+)/H(+) exchangers (NHE), NHE-1, NHE-2, NHE-3, NHE-4, and NHE-5 in both cell lines. EGF stimulated proton efflux in both cell lines. This effect was significantly attenuated by MIA, 5-(n-methyl-N-isobutyl) amiloride, a selective inhibitor of NHE-1 and NHE-2, and orpk cilia (-) cells were more sensitive to MIA than control cells (P < 0.01). EGF significantly induced extracellular signal-regulated kinase (ERK) phosphorylation in both cilia (+) and cilia (-) cells (63.3 and 123.6%, respectively), but the effect was more pronounced in orpk cilia (-) cells (P < 0.01). MIA significantly attenuated EGF-induced ERK phosphorylation only in orpk cilia (-) cells (P < 0.01). EGF increased proliferation of orpk cilia (+) cells and orpk cilia (-) cells, respectively, and MIA at 1-5 μM attenuated EGF-induced proliferation in orpk cilia (-) cells without affecting proliferation of orpk cilia (+) cells. EGF-induced proliferation of both cell lines was significantly decreased by the EGFR tyrosine kinase inhibitor AG1478 and MEK inhibitor PD98059. These results suggest that EGF exerts mitogenic effects in the orpk cilia (-) cells via activation of growth-associated amiloride-sensitive NHEs and ERK.
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Affiliation(s)
- Sonya D Coaxum
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina
| | - Mary G Blanton
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina
| | - Alisha Joyner
- College of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Tanjina Akter
- Department of Medicine, Division of Rheumatology and Immunology, Medical University of South Carolina, Charleston, South Carolina
| | - P Darwin Bell
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina; Medical and Research Services of the Ralph H. Johnson VAMC, Charleston, Carolina
| | - Louis M Luttrell
- Department of Medicine, Division of Endocrinology, Medical University of South Carolina, Charleston, South Carolina; and
| | - John R Raymond
- Department of Medicine, Division of Nephrology, Medical College of Wisconsin and the Medical Service of the Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin
| | - Mi-Hye Lee
- Department of Medicine, Division of Endocrinology, Medical University of South Carolina, Charleston, South Carolina; and
| | - Paul A Blichmann
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina
| | - Maria N Garnovskaya
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina
| | - Takamitsu Saigusa
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina;
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Liu Y, Hitomi H, Diah S, Deguchi K, Mori H, Masaki T, Nakano D, Kobori H, Nishiyama A. Roles of Na⁺/H⁺ exchanger type 1 and intracellular pH in angiotensin II-induced reactive oxygen species generation and podocyte apoptosis. J Pharmacol Sci 2014; 122:176-83. [PMID: 23800993 DOI: 10.1254/jphs.12291fp] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
A growing body of evidence suggests that podocyte apoptosis is a major cause of decreased podocyte number, which leads to albuminuria and glomerular injury. The aim of this study was to clarify the molecular mechanisms of angiotensin II (Ang II)-induced apoptosis in cultured mouse podocytes. We examined the effects of Ang II (100 nmol/L) on apoptosis, superoxide anions, and cytosol pH in podocytes. For intracellular pH measurements, image analysis was conducted using confocal laser microscopy after incubation with carboxy-seminaphthorhodafluor-1. Superoxide anions and intracellular pH were elevated with Ang II treatment. Apoptotic cell numbers, as measured by TUNEL staining and caspase 3 activity, were also augmented in the Ang II-treated group. Pre-treatment with olmesartan (100 nmol/L, an Ang II type 1-receptor blocker), apocynin (50 μmol/L, NADPH oxidase inhibitor), or 5-N,N hexamethylene amiloride [30 μmol/L, Na⁺/H⁺ exchanger type 1 (NHE-1) inhibitor] abolished Ang II-induced podocyte apoptosis, whereas NHE-1 mRNA and protein expression was not affected by Ang II treatment. Moreover, Ang II increased NHE-1 phosphorylation. These results suggest that superoxide production, NHE-1 activation, and intracellular alkalization were early features prior to apoptosis in Ang II-treated mouse podocytes, and may offer new insights into the mechanisms responsible for Ang II-induced podocyte injury.
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Affiliation(s)
- Ya Liu
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Japan
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Na+/H+ exchanger-1 reduces podocyte injury caused by endoplasmic reticulum stress via autophagy activation. J Transl Med 2014; 94:439-54. [PMID: 24566932 DOI: 10.1038/labinvest.2014.4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/14/2013] [Accepted: 12/30/2013] [Indexed: 12/26/2022] Open
Abstract
Podocyte injury has a critical role in the pathogenesis of proteinuria. Induction of endoplasmic reticulum (ER) stress is thought to lead to podocyte injury; however, no effective strategy for reducing ER stress-induced injury has been identified. We investigated specific mechanisms for reducing podocyte injury caused by ER stress. We found that the induction of ER stress in podocytes was related to cytoskeleton injury and increased proteinuria, which was associated with autophagy activation and downregulation of Na(+)/H(+) exchanger-1 (NHE-1) in the rat model of passive Heymann nephritis. Using mouse podocyte cells (MPCs), we showed that ER stress could lead to podocyte injury accompanied by autophagy activation, and the disturbance of autophagy aggravated cytoskeleton loss under conditions of ER stress. The balance between autophagy activation and ER stress was critical to podocyte survival, in which the efficiency of autophagy could have a pivotal role. Strikingly, the overexpression and small interfering RNA knockdown of NHE-1 results suggested that NHE-1 exerts a protective effect by reducing the loss of synaptopodin in MPCs exposed to ER stress. This protective mechanism involves NHE-1 activation of autophagy via the PI3K/Akt pathway to reduce ER stress injury in podocytes. This mechanism may provide a new pathway to prevent podocyte injury.
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Li JF, Chen S, Feng JD, Zhang MY, Liu XX. RETRACTED: Probucol via inhibition of NHE1 attenuates LPS-accelerated atherosclerosis and promotes plaque stability in vivo. Exp Mol Pathol 2014; 96:250-6. [PMID: 24594116 DOI: 10.1016/j.yexmp.2014.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 02/23/2014] [Indexed: 01/29/2023]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors. Concern had previously been raised about the veracity of some of the data in Figure 6 which appears to contain similar experimental data to many other publications, described here: https://pubpeer.com/publications/72ACDBE9751C8FD443A223FEB806E8#. The corresponding author contacted the journal and acknowledged that some of the experiments were not conducted by the authors themselves and they no longer have confidence in the reliability of the results. The authors would like to apologize for any inconvenience caused. The Editor-in-Chief agreed to retract the article.
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Affiliation(s)
- Jian-Fei Li
- Department of Cardiology, The 4th Hospital of Harbin Medical University, Harbin 150001, China
| | - Song Chen
- Department of Cardiology, The 4th Hospital of Harbin Medical University, Harbin 150001, China
| | - Jun-Duo Feng
- Health examination center, Hospital of Heilongjiang Armed Police Corps, 558 Xinyanglu Road, Harbin 150076, China
| | - Ming-Yu Zhang
- Department of Cardiology, The 4th Hospital of Harbin Medical University, Harbin 150001, China
| | - Xiao-Xia Liu
- Department of Cardiology, The 4th Hospital of Harbin Medical University, Harbin 150001, China
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Khundmiri SJ, Salyer SA, Farmer B, Qipshidze-Kelm N, Murray RD, Clark BJ, Xie Z, Pressley TA, Lederer ED. Structural determinants for the ouabain-stimulated increase in Na-K ATPase activity. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1089-102. [PMID: 24566089 DOI: 10.1016/j.bbamcr.2014.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 02/06/2014] [Accepted: 02/12/2014] [Indexed: 01/11/2023]
Abstract
Recent studies suggest that at low concentrations, ouabain increases Na-K ATPase and NHE1 activity and activates the Src signaling cascade in proximal tubule cells. Our laboratory demonstrated that low concentrations of ouabain increase blood pressure in rats. We hypothesize that ouabain-induced increase in blood pressure and Na-K ATPase activity requires NHE1 activity and association. To test this hypothesis we treated rats with ouabain (1μgkg body wt(-1)day(-1)) for 9days in the presence or absence of the NHE1 inhibitor, zoniporide. Ouabain stimulated a significant increase in blood pressure which was prevented by zoniporide. Using NHE1-expressing Human Kidney cells 2 (HK2), 8 (HK8) and 11 (HK11) and Mouse Kidney cells from Wild type (WT) and NHE1 knock-out mice (SWE) cell lines, we show that ouabain stimulated Na-K ATPase activity and surface expression in a Src-dependent manner in NHE1-expressing cells but not in NHE1-deplete cells. Zoniporide prevented ouabain-induced stimulation of (86)Rb uptake in the NHE1-expressing cells. FRET and TIRF microscopy showed that ouabain increased association between GFP-NHE1 and mCherry-Na-K ATPase transfected into NHE1-deficient SWE cells. Mutational analysis demonstrated that the caveolin binding motif (CBM) of Na-K ATPase α1 is required for translocation of both Na-K ATPase α1 and NHE1 to the basolateral membrane. Mutations in activity or scaffold domains of NHE1 resulted in loss of ouabain-mediated regulation of Na-K ATPase. These results support that NHE1 is required for the ouabain-induced increase in blood pressure, and that the caveolin binding motif of Na-K ATPase α1 as well as the activity and scaffolding domains of NHE1 are required for their functional association.
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Affiliation(s)
- Syed J Khundmiri
- Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA; Department of Medicine/Kidney Disease Program, University of Louisville, Louisville, KY, USA; Department of Physiology, University of Louisville, Louisville, KY, USA.
| | - Sarah A Salyer
- Department of Medicine/Kidney Disease Program, University of Louisville, Louisville, KY, USA; Department of Physiology, University of Louisville, Louisville, KY, USA
| | - Brandon Farmer
- Department of Medicine/Kidney Disease Program, University of Louisville, Louisville, KY, USA
| | | | - Rebecca D Murray
- Department of Medicine/Kidney Disease Program, University of Louisville, Louisville, KY, USA; Department of Physiology, University of Louisville, Louisville, KY, USA
| | - Barbara J Clark
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, USA
| | - Zijian Xie
- Department of Physiology, University of Toledo College of Medicine, Toledo, OH, USA
| | - Thomas A Pressley
- Department of Cell Physiology and Molecular Biophysics, Texas Tech Univ. Health Sciences Center, Lubbock, TX, USA
| | - Eleanor D Lederer
- Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA; Department of Medicine/Kidney Disease Program, University of Louisville, Louisville, KY, USA; Department of Physiology, University of Louisville, Louisville, KY, USA
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Loh SH, Lee CY, Tsai YT, Shih SJ, Chen LW, Cheng TH, Chang CY, Tsai CS. Intracellular Acid-extruding regulators and the effect of lipopolysaccharide in cultured human renal artery smooth muscle cells. PLoS One 2014; 9:e90273. [PMID: 24587308 PMCID: PMC3931831 DOI: 10.1371/journal.pone.0090273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/31/2014] [Indexed: 12/25/2022] Open
Abstract
Homeostasis of the intracellular pH (pHi) in mammalian cells plays a pivotal role in maintaining cell function. Thus far, the housekeeping Na(+)-H(+) exchanger (NHE) and the Na(+)-HCO3(-) co-transporter (NBC) have been confirmed in many mammalian cells as major acid extruders. However, the role of acid-extruding regulators in human renal artery smooth muscle cells (HRASMCs) remains unclear. It has been demonstrated that lipopolysaccharide (LPS)-induced vascular occlusion is associated with the apoptosis, activating calpain and increased [Ca(2+)]i that are related to NHE1 activity in endothelia cells. This study determines the acid-extruding mechanisms and the effect of LPS on the resting pHi and active acid extruders in cultured HRASMCs. The mechanism of pHi recovery from intracellular acidosis (induced by NH4Cl-prepulse) is determined using BCECF-fluorescence in cultured HRASMCs. It is seen that (a) the resting pHi is 7.19 ± 0.03 and 7.10 ± 0.02 for HEPES- and CO2/HCO3(-)- buffered solution, respectively; (b) apart from the housekeeping NHE1, another Na(+)-coupled HCO3(-) transporter i.e. NBC, functionally co-exists to achieve acid-equivalent extrusion; (c) three different isoforms of NBC: NBCn1 (SLC4A7; electroneutral), NBCe1 (SLC4A4; electrogenic) and NBCe2 (SLC4A5), are detected in protein/mRNA level; and (d) pHi and NHE protein expression/activity are significantly increased by LPS, in both a dose- and time- dependent manner, but NBCs protein expression is not. In conclusion, it is demonstrated, for the first time, that four pHi acid-extruding regulators: NHE1, NBCn1, NBCe1 and NBCe2, co-exist in cultured HRASMCs. LPS also increases cellular growth, pHi and NHE in a dose- and time-dependent manner.
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Affiliation(s)
- Shih-Hurng Loh
- Department of Pharmacology, National Defense Medical Center, Taipei City, Taiwan
- * E-mail:
| | - Chung-Yi Lee
- Department of Cardiovascular Surgery, Tri-Service General Hospital, Taipei, Taiwan
| | - Yi-Ting Tsai
- Department of Cardiovascular Surgery, Tri-Service General Hospital, Taipei, Taiwan
| | - Shou-Jou Shih
- Department of Pharmacology, National Defense Medical Center, Taipei City, Taiwan
| | - Li-Wei Chen
- Department of Pharmacology, National Defense Medical Center, Taipei City, Taiwan
| | - Tzu-Hurng Cheng
- Department of Biological Science and Technology, College of Life Sciences, China Medical University, Taichung, Taiwan
| | - Chung-Yi Chang
- Department of General Surgery, Cheng-Hsieng General Hospital, Taipei, Taiwan
| | - Chein-Sung Tsai
- Department of Cardiovascular Surgery, Tri-Service General Hospital, Taipei, Taiwan
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Khan S, Abu Jawdeh BG, Goel M, Schilling WP, Parker MD, Puchowicz MA, Yadav SP, Harris RC, El-Meanawy A, Hoshi M, Shinlapawittayatorn K, Deschênes I, Ficker E, Schelling JR. Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis. J Clin Invest 2014; 124:1057-68. [PMID: 24531551 DOI: 10.1172/jci71863] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/11/2013] [Indexed: 12/12/2022] Open
Abstract
Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2-dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity.
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Stock C, Ludwig FT, Hanley PJ, Schwab A. Roles of ion transport in control of cell motility. Compr Physiol 2013; 3:59-119. [PMID: 23720281 DOI: 10.1002/cphy.c110056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.
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Affiliation(s)
- Christian Stock
- Institute of Physiology II, University of Münster, Münster, Germany.
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Wang WJ, Shi XX, Liu YW, He YQ, Wang YZ, Yang CX, Gao F. The mechanism underlying the effects of the cell surface ATP synthase on the regulation of intracellular acidification during acidosis. J Cell Biochem 2013; 114:1695-703. [PMID: 23386430 DOI: 10.1002/jcb.24511] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 01/24/2013] [Indexed: 12/19/2022]
Abstract
The F1F0 ATP synthase has recently become the focus of anti-cancer research. It was once thought that ATP synthases were located strictly on the inner mitochondrial membrane; however, in 1994, it was found that some ATP synthases localized to the cell surface. The cell surface ATP synthases are involved in angiogenesis, lipoprotein metabolism, innate immunity, hypertension, the regulation of food intake, and other processes. Inhibitors of this synthase have been reported to be cytotoxic and to induce intracellular acidification. However, the mechanisms by which these effects are mediated and the molecular pathways that are involved remain unclear. In this study, we aimed to determine whether the inhibition of cell proliferation and the induction of cell apoptosis that are induced by inhibitors of the cell surface ATP synthase are associated with intracellular acidification and to investigate the mechanism that underlines the effects of this inhibition, particularly in an acidic tumor environment. We demonstrated that intracellular acidification contributes to the cell proliferation inhibition that is mediated by cell surface ATP synthase inhibitors, but not to the induction of apoptosis. Intracellular acidification is only one of the mechanisms of ecto-ATP synthase-targeted antitumor drugs. We propose that intracellular acidification in combination with the inhibition of cell surface ATP generation induce cell apoptosis after cell surface ATP synthase blocked by its inhibitors. A better understanding of the mechanisms activated by ecto-ATP synthase-targeted cancer therapies may facilitate the development of potent anti-tumor therapies, which target this enzyme and do not exhibit clinical limitations.
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Affiliation(s)
- Wen-juan Wang
- Department of Laboratory Medicine, Shanghai Sixth People's Hospital of Shanghai, Shanghai JiaoTong University School of Medicine, Shanghai 200233, PR China
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Liu G, Hitomi H, Rahman A, Nakano D, Mori H, Masaki T, Ma H, Iwamoto T, Kobori H, Nishiyama A. High sodium augments angiotensin II-induced vascular smooth muscle cell proliferation through the ERK 1/2-dependent pathway. Hypertens Res 2013; 37:13-8. [PMID: 24026042 DOI: 10.1038/hr.2013.108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 05/22/2013] [Accepted: 05/28/2013] [Indexed: 01/19/2023]
Abstract
Angiotensin II (Ang II)-induced vascular injury is exacerbated by high-salt diets. This study examined the effects of high-sodium level on Ang II-induced cell proliferation in rat vascular smooth muscle cells (VSMCs). The cells were cultured in a standard medium containing 137.5 mmol l(-1) of sodium. The high-sodium medium (140 mmol l(-1)) contained additional sodium chloride. Extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was determined by western blot analysis. Cell proliferation was evaluated by [(3)H]-thymidine incorporation. Ang II (100 nmol l(-1)) significantly increased ERK 1/2 phosphorylation and cell proliferation in the both medium containing standard sodium and high sodium. High-sodium level augmented Ang II-induced ERK 1/2 phosphorylation and cell proliferation compared with standard sodium. Pre-treatment with candesartan (1 μmol l(-1), Ang II type 1 receptor blocker) or PD98095 (10 μmol l(-1), ERK kinase iinhibitor) abolished the proliferative effect induced by high sodium/Ang II. Pre-treatment with 5-N,N-hexamethylene amiloride (30 μmol l(-1), Na(+)/H(+) exchanger type 1 (NHE-1) inhibitor), but not SN-6 (10 μmol l(-1), Na(+)/Ca(2+) exchanger inhibitor) or ouabain (1 mmol l(-1), Na(+)/K(+)-ATPase inhibitor) attenuated ERK 1/2 phosphorylation or cell proliferation. Osmotic pressure or chloride had no effect on Ang II-induced proliferative changes. High-sodium level did not affect Ang II receptor expression. Ang II increased intracellular pH via NHE-1 activation, and high-sodium level augmented the pH increase induced by Ang II. These data suggest that high-sodium level directly augments Ang II-induced VSMC proliferation through NHE-1- and ERK 1/2-dependent pathways and may offer new insights into the mechanisms of vascular remodeling by high-sodium/Ang II.
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Affiliation(s)
- Gang Liu
- 1] Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan [2] Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Hirofumi Hitomi
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Asadur Rahman
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hirohito Mori
- Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Tsutomu Masaki
- Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hong Ma
- Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Hiroyuki Kobori
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
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Li J, Xu L, Ye J, Li X, Zhang D, Liang D, Xu X, Qi M, Li C, Zhang H, Wang J, Liu Y, Zhang Y, Zhou Z, Liang X, Li J, Peng L, Zhu W, Chen YH. Aberrant dynamin 2-dependent Na(+) /H(+) exchanger-1 trafficking contributes to cardiomyocyte apoptosis. J Cell Mol Med 2013; 17:1119-27. [PMID: 23837875 PMCID: PMC4118171 DOI: 10.1111/jcmm.12086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 05/13/2013] [Indexed: 02/05/2023] Open
Abstract
Sarcolemmal Na+/H+ exchanger 1 (NHE1) activity is essential for the intracellular pH (pHi) homeostasis in cardiac myocytes. Emerging evidence indicates that sarcolemmal NHE1 dysfunction was closely related to cardiomyocyte death, but it remains unclear whether defective trafficking of NHE1 plays a role in the vital cellular signalling processes. Dynamin (DNM), a large guanosine triphosphatase (GTPase), is best known for its roles in membrane trafficking events. Herein, using co-immunoprecipitation, cell surface biotinylation and confocal microscopy techniques, we investigated the potential regulation on cardiac NHE1 activity by DNM. We identified that DNM2, a cardiac isoform of DNM, directly binds to NHE1. Overexpression of a wild-type DNM2 or a dominant-negative DNM2 mutant with defective GTPase activity in adult rat ventricular myocytes (ARVMs) facilitated or retarded the internalization of sarcolemmal NHE1, whereby reducing or increasing its activity respectively. Importantly, the increased NHE1 activity associated with DNM2 deficiency led to ARVMs apoptosis, as demonstrated by cell viability, terminal deoxynucleotidyl transferase–mediated dUTP nick-end labelling assay, Bcl-1/Bax expression and caspase-3 activity, which were effectively rescued by pharmacological inhibition of NHE1 with zoniporide. Thus, our results demonstrate that disruption of the DNM2-dependent retrograde trafficking of NHE1 contributes to cardiomyocyte apoptosis.
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Affiliation(s)
- Jun Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China; Institute of Medical Genetics, Tongji University, Shanghai, China
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Abstract
Conditionally disordered proteins can alternate between highly ordered and less ordered configurations under physiological conditions. Whereas protein function is often associated with the ordered conformation, for some of these conditionally unstructured proteins, the opposite applies: Their activation is associated with their unfolding. An example is the small periplasmic chaperone HdeA, which is critical for the ability of enteric bacterial pathogens like Escherichia coli to survive passage through extremely acidic environments, such as the human stomach. At neutral pH, HdeA is a chaperone-inactive dimer. On a shift to low pH, however, HdeA monomerizes, partially unfolds, and becomes rapidly active in preventing the aggregation of substrate proteins. By mutating two aspartic acid residues predicted to be responsible for the pH-dependent monomerization of HdeA, we have succeeded in isolating an HdeA mutant that is active at neutral pH. We find this HdeA mutant to be substantially destabilized, partially unfolded, and mainly monomeric at near-neutral pH at a concentration at which it prevents aggregation of a substrate protein. These results provide convincing evidence for direct activation of a protein by partial unfolding.
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Amiloride attenuates lipopolysaccharide-accelerated atherosclerosis via inhibition of NHE1-dependent endothelial cell apoptosis. Acta Pharmacol Sin 2013; 34:231-8. [PMID: 23274414 DOI: 10.1038/aps.2012.155] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AIM To investigate the effects of the potassium-sparing diuretic amiloride on endothelial cell apoptosis during lipopolysaccharide (LPS)-accelerated atherosclerosis. METHODS Human umbilical vein endothelial cells (HUVECs) were exposed to LPS (100 ng/mL) in the presence of drugs tested. The activity of Na(+)/H(+) exchanger 1 (NHE1) and calpain, intracellular free Ca(2+)level ([Ca(2+)](i)), as well as the expression of apoptosis-related proteins in the cells were measured. For in vivo study, ApoE-deficient (ApoE(-/-)) mice were fed high-fat diets with 0.5% (w/w) amiloride for 4 weeks and LPS (10 μg/mouse) infusion into caudal veins. Afterwards, atherosclerotic lesions, NHE1 activity and Bcl-2 expression in the aortic tissues were evaluated. RESULTS LPS treatment increased NHE1 activity and [Ca(2+)](i) in HUVECs in a time-dependent manner, which was associated with increased activity of the Ca(2+)-dependent protease calpain. Amiloride (1-10 μmol/L) significantly suppressed LPS-induced increases in NHE1 activity, [Ca(2+)](i). and calpain activity. In the presence of the Ca(2+) chelator BAPTA (0.5 mmol/L), LPS-induced increase of calpain activity was also abolished. In LPS-treated HUVECs, the expression of Bcl-2 protein was significantly decreased without altering its mRNA level. In the presence of amiloride (10 μmol/L) or the calpain inhibitor ZLLal (50 μmol/L), the down-regulation of Bcl-2 protein by LPS was blocked. LPS treatment did not alter the expression of Bax and Bak proteins in HUVECs. In the presence of amiloride, BAPTA or ZLLal, LPS-induced HUVEC apoptosis was significantly attenuated. In ApoE(-/-) mice, administration of amiloride significantly suppressed LPS-accelerated atherosclerosis and LPS-induced increase of NHE1 activity, and reversed LPS-induced down-regulation of Bcl-2 expression. CONCLUSION LPS stimulates NHE1 activity, increases [Ca(2+)](i), and activates calpain, which leads to endothelial cell apoptosis related to decreased Bcl-2 expression. Amiloride inhibits NHE1 activity, thus attenuates LPS-accelerated atherosclerosis in mice.
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Abstract
The physicochemical properties of small molecules as well as macromolecules are modulated by solution pH, and DNA is no exception. Special sequences of DNA can adopt unusual conformations e.g., triplex, i-motif and A-motif, depending on solution pH. The specific range of pH for these unusual structures is dictated by the pKa of protonation of the relevant nucleobase involved in the resultant non-canonical base pairing that is required to stabilise the structure. The biological significance of these pH-dependent structures is not yet clear. However, these non-B-DNA structures have been used to design different devices to direct chemical reactions, generate mechanical force, sense pH, etc. The performance of these devices can be monitored by a photonic signal. They are autonomous and their ‘waste free’ operation cycles makes them highly processive. Applications of these devices help to increase understanding of the structural polymorphism of the motifs themselves. The design of these devices has continuously evolved to improve their performance efficiency in different contexts. In some examples, these devices have been shown to perform inside complex living systems with similar efficiencies, to report on the chemical environment there. The robust performance of these devices opens up exciting possibilities for pH-sensitive DNA devices in the study of various pH-regulated biological events.
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Affiliation(s)
- Sonali Saha
- National Centre for Biological Sciences TIFR, GKVK, Bellary Road, Bangalore 560065 India
| | - Yamuna Krishnan*
- National Centre for Biological Sciences TIFR, GKVK, Bellary Road, Bangalore 560065 India
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Zhao Y, Cui G, Zhang N, Liu Z, Sun W, Peng Q. Lipopolysaccharide induces endothelial cell apoptosis via activation of Na(+)/H(+) exchanger 1 and calpain-dependent degradation of Bcl-2. Biochem Biophys Res Commun 2012; 427:125-32. [PMID: 22995319 DOI: 10.1016/j.bbrc.2012.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 09/06/2012] [Indexed: 11/16/2022]
Abstract
The calcium-dependent protease calpain is involved in lipopolysaccharide (LPS)-induced endothelial injury. The activation of Na(+)/H(+) exchanger (NHE) is responsible to increase intracellular Ca(2+) (Ca(i)(2+)) in cardiovascular diseases. Here we hypothesized that activation of NHE mediates LPS-induced endothelial cell apoptosis via calcium-dependent calpain pathway. Our results revealed that LPS-induced increases in NHE activity are dependent on NHE1 in human umbilical vein endothelial cells (HUVECs). Treatment of HUVECs with LPS increased the NHE1 activity in a time-dependent manner associated with the increased Ca(i)(2+), which resulted in enhanced calpain activity as well as HUVECs apoptosis via NHE1-dependent degradation of Bcl-2.
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Affiliation(s)
- Yuxi Zhao
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
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Zaun HC, Shrier A, Orlowski J. N-myristoylation and Ca2+ binding of calcineurin B homologous protein CHP3 are required to enhance Na+/H+ exchanger NHE1 half-life and activity at the plasma membrane. J Biol Chem 2012; 287:36883-95. [PMID: 22984264 DOI: 10.1074/jbc.m112.394700] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcineurin B homologous proteins (CHP) are N-myristoylated, EF-hand Ca(2+)-binding proteins that regulate multiple cellular processes, including intracellular pH homeostasis. Previous work has shown that the heart-enriched isoform, CHP3, regulates the plasmalemmal Na(+)/H(+) exchanger NHE1 isoform by enhancing its rate of oligosaccharide maturation and exocytosis as well as its half-life and transport activity at the cell surface (Zaun, H. C., Shrier, A., and Orlowski, J. (2008) J. Biol. Chem. 283, 12456-12467). However, the molecular basis for this effect is not well understood. In this report, we investigated whether the N-myristoylation and Ca(2+)-binding domains of CHP3 are important elements for regulating NHE1. Mutation of residues essential for either N-myristoylation (G2A) or calcium binding (D123A) did not prevent the interaction of CHP3 with NHE1, although the D123A mutant no longer showed elevated binding to NHE1 in the presence of Ca(2+) when assessed using in vitro binding assays. Disruption of either site also did not impair the ability of CHP3 to stimulate the biosynthetic processing and trafficking of NHE1 to the plasma membrane nor did it affect the H(+) sensitivity of the exchanger. However, they did significantly reduce the cell surface half-life and near maximal transport velocity of NHE1 to a similar extent. Simultaneous mutation of both sites (G2A/D123A) gave results identical to the individual substitutions. This finding suggests that both domains in CHP3 are interdependent and may function cooperatively as a Ca(2+)-myristoyl switch mechanism to selectively stabilize the NHE1·CHP3 complex at the cell surface in a conformation that promotes optimal transport activity.
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Affiliation(s)
- Hans C Zaun
- Department of Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
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