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Garneau AP, Slimani S, Tremblay LE, Fiola MJ, Marcoux AA, Isenring P. K +-Cl - cotransporter 1 (KCC1): a housekeeping membrane protein that plays key supplemental roles in hematopoietic and cancer cells. J Hematol Oncol 2019; 12:74. [PMID: 31296230 PMCID: PMC6624878 DOI: 10.1186/s13045-019-0766-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/30/2019] [Indexed: 01/04/2023] Open
Abstract
During the 1970s, a Na+-independent, ouabain-insensitive, N-ethylmaleimide-stimulated K+-Cl- cotransport mechanism was identified in red blood cells for the first time and in a variety of cell types afterward. During and just after the mid-1990s, three closely related isoforms were shown to account for this mechanism. They were termed K+-Cl- cotransporter 1 (KCC1), KCC3, and KCC4 according to the nomenclature of Gillen et al. (1996) who had been the first research group to uncover the molecular identity of a KCC, that is, of KCC1 in rabbit kidney. Since then, KCC1 has been found to be the most widely distributed KCC isoform and considered to act as a housekeeping membrane protein. It has perhaps received less attention than the other isoforms for this reason, but as will be discussed in the following review, there is probably more to KCC1 than meets the eye. In particular, the so-called housekeeping gene also appears to play crucial and specific roles in normal as well as pathological hematopoietic and in cancer cells.
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Affiliation(s)
- A P Garneau
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada
- Cardiometabolic Axis, School of Kinesiology and Physical Activity Sciences, University of Montréal, 900, rue Saint-Denis, Montréal (Qc), H2X 0A9, Canada
| | - S Slimani
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada
| | - L E Tremblay
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada
| | - M J Fiola
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada
| | - A A Marcoux
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada
| | - P Isenring
- From the Nephrology Research Group, Department of Medicine, Laval University, 11, côte du Palais, Québec (Qc), G1R 2J6, Canada.
- L'Hôtel-Dieu de Québec Institution, 10, rue McMahon, Québec (Qc), G1R 2J6, Canada.
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2
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Zhou S, Giannetto M, DeCourcey J, Kang H, Kang N, Li Y, Zheng S, Zhao H, Simmons WR, Wei HS, Bodine DM, Low PS, Nedergaard M, Wan J. Oxygen tension-mediated erythrocyte membrane interactions regulate cerebral capillary hyperemia. SCIENCE ADVANCES 2019; 5:eaaw4466. [PMID: 31149638 PMCID: PMC6541463 DOI: 10.1126/sciadv.aaw4466] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/17/2019] [Indexed: 05/24/2023]
Abstract
The tight coupling between cerebral blood flow and neural activity is a key feature of normal brain function and forms the basis of functional hyperemia. The mechanisms coupling neural activity to vascular responses, however, remain elusive despite decades of research. Recent studies have shown that cerebral functional hyperemia begins in capillaries, and red blood cells (RBCs) act as autonomous regulators of brain capillary perfusion. RBCs then respond to local changes of oxygen tension (PO2) and regulate their capillary velocity. Using ex vivo microfluidics and in vivo two-photon microscopy, we examined RBC capillary velocity as a function of PO2 and showed that deoxygenated hemoglobin and band 3 interactions on RBC membrane are the molecular switch that responds to local PO2 changes and controls RBC capillary velocity. Capillary hyperemia can be controlled by manipulating RBC properties independent of the neurovascular unit, providing an effective strategy to treat or prevent impaired functional hyperemia.
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Affiliation(s)
- Sitong Zhou
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - James DeCourcey
- College of Osteopathic Medicine, University of New England, Biddeford, ME 04005, USA
| | - Hongyi Kang
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Ning Kang
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Yizeng Li
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Suilan Zheng
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Hetince Zhao
- New York University Langone Medical Center, New York, NY 10010, USA
| | | | - Helen S. Wei
- Rutgers New Jersey Medical School, Newark, NJ 07101, USA
| | - David M. Bodine
- National Human Genome Research Institute, Bethesda, MD 20894, USA
| | - Philip S. Low
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jiandi Wan
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
- Department of Chemical Engineering, University of California, Davis, Davis, CA 95616, USA
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3
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Hannemann A, Rees DC, Brewin JN, Noe A, Low B, Gibson JS. Oxidative stress and phosphatidylserine exposure in red cells from patients with sickle cell anaemia. Br J Haematol 2018; 182:567-578. [PMID: 29938778 PMCID: PMC6120535 DOI: 10.1111/bjh.15441] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/13/2018] [Indexed: 12/14/2022]
Abstract
Phosphatidylserine (PS) exposure increases as red cells age, and is an important signal for the removal of senescent cells from the circulation. PS exposure is elevated in red cells from sickle cell anaemia (SCA) patients and is thought to enhance haemolysis and vaso-occlusion. Although precise conditions leading to its externalisation are unclear, high intracellular Ca2+ has been implicated. Red cells from SCA patients are also exposed to an increased oxidative challenge, and we postulated that this stimulates PS exposure, through increased Ca2+ levels. We tested four different ways of generating oxidative stress: hypoxanthine and xanthine oxidase, phenazine methosulphate, nitrite and tert-butyl hydroperoxide, together with thiol modification with N-ethylmaleimide (NEM), dithiothreitol and hypochlorous acid (HOCl), in red cells permeabilised to Ca2+ using bromo-A23187. Unexpectedly, our findings showed that the four oxidants significantly reduced Ca2+ -induced PS exposure (by 40-60%) with no appreciable effect on Ca2+ affinity. By contrast, NEM markedly increased PS exposure (by about 400%) and slightly but significantly increased the affinity for Ca2+ . Dithiothreitol modestly reduced PS exposure (by 25%) and HOCl had no effect. These findings emphasise the importance of thiol modification for PS exposure in sickle cells but suggest that increased oxidant stress alone is not important.
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Affiliation(s)
- Anke Hannemann
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - David C. Rees
- Department of Paediatric HaematologyKing's College HospitalKing's College London School of MedicineLondonUK
| | - John N. Brewin
- Department of Paediatric HaematologyKing's College HospitalKing's College London School of MedicineLondonUK
| | - Andreas Noe
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Ben Low
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - John S. Gibson
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
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4
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Huisjes R, Bogdanova A, van Solinge WW, Schiffelers RM, Kaestner L, van Wijk R. Squeezing for Life - Properties of Red Blood Cell Deformability. Front Physiol 2018; 9:656. [PMID: 29910743 PMCID: PMC5992676 DOI: 10.3389/fphys.2018.00656] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/14/2018] [Indexed: 12/25/2022] Open
Abstract
Deformability is an essential feature of blood cells (RBCs) that enables them to travel through even the smallest capillaries of the human body. Deformability is a function of (i) structural elements of cytoskeletal proteins, (ii) processes controlling intracellular ion and water handling and (iii) membrane surface-to-volume ratio. All these factors may be altered in various forms of hereditary hemolytic anemia, such as sickle cell disease, thalassemia, hereditary spherocytosis and hereditary xerocytosis. Although mutations are known as the primary causes of these congenital anemias, little is known about the resulting secondary processes that affect RBC deformability (such as secondary changes in RBC hydration, membrane protein phosphorylation, and RBC vesiculation). These secondary processes could, however, play an important role in the premature removal of the aberrant RBCs by the spleen. Altered RBC deformability could contribute to disease pathophysiology in various disorders of the RBC. Here we review the current knowledge on RBC deformability in different forms of hereditary hemolytic anemia and describe secondary mechanisms involved in RBC deformability.
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Affiliation(s)
- Rick Huisjes
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zürich, Switzerland
| | - Wouter W van Solinge
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Raymond M Schiffelers
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Saarbrücken, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Richard van Wijk
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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5
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Lee MY, Yang DK, Kim SJ. Alterations of Mg 2+ After Hemorrhagic Shock. Biol Trace Elem Res 2017; 180:120-126. [PMID: 28315119 DOI: 10.1007/s12011-017-0994-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/08/2017] [Indexed: 10/19/2022]
Abstract
Hemorrhagic shock is generally characterized by hemodynamic instability with cellular hypoxia and diminishing cellular function, resulting from an imbalance between systemic oxygen delivery and consumption and redistribution of fluid and electrolytes. Magnesium (Mg) is the fourth most abundant cation overall and second most abundant intracellular cation in the body and an essential cofactor for the energy production and cellular metabolism. Data for blood total Mg (tMg; free-ionized, protein-bound, and anion-bound forms) and free Mg2+ levels after a traumatic injury are inconsistent and only limited information is available on hemorrhagic effects on free Mg2+ as the physiologically active form. The aim of this study was to determine changes in blood Mg2+ and tMg after hemorrhage in rats identifying mechanism and origin of the changes in blood Mg2+. Hemorrhagic shock produced significant increases in blood Mg2+, plasma tMg, Na+, K+, Cl-, anion gap, partial pressures of oxygen, glucose, and blood urea nitrogen but significant decreases in RBC tMg, blood Ca2+, HCO3-, pH, partial pressures of carbon dioxide, hematocrit, hemoglobin, total cholesterol, and plasma/RBC ATP. During hemorrhagic shock, K+, anion gap, and BUN showed significant positive correlations with changes in blood Mg2+ level, while Ca2+, pH, and T-CHO correlated to Mg2+ in a negative manner. In conclusion, hemorrhagic shock induced an increase in both blood-free Mg2+ and tMg, resulted from Mg2+ efflux from metabolic damaged cell with acidosis and ATP depletion.
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Affiliation(s)
- Mun-Young Lee
- Department of Occupational Therapy, College of Health Science, Honam University, Kwangju, 62399, Republic of Korea
| | - Dong Kwon Yang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Iksan Campus, 79 Gobong-ro, Iksan-si, Jeollabuk-do, 54596, Republic of Korea
| | - Shang-Jin Kim
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Iksan Campus, 79 Gobong-ro, Iksan-si, Jeollabuk-do, 54596, Republic of Korea.
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6
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Al Balushi HWM, Wali Y, Al Awadi M, Al-Subhi T, Rees DC, Brewin JN, Hannemann A, Gibson JS. The super sickling haemoglobin HbS-Oman: a study of red cell sickling, K + permeability and associations with disease severity in patients heterozygous for HbA and HbS-Oman (HbA/S-Oman genotype). Br J Haematol 2017; 179:256-265. [PMID: 28699687 DOI: 10.1111/bjh.14851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/04/2017] [Indexed: 11/30/2022]
Abstract
Studying different sickle cell genotypes may throw light on the pathogenesis of sickle cell disease (SCD). Here, the clinical profile, red cell sickling and K+ permeability in 29 SCD patients (15 patients with severe disease and 14 with a milder form) of HbA/S-Oman genotype were analysed. The super sickling nature of this Hb variant was confirmed. The red cell membrane permeability to K+ was markedly abnormal with elevated activities of Psickle , Gardos channel and KCl cotransporter (KCC). Results were consistent with Ca2+ entry and Mg2+ loss via Psickle stimulating Gardos channel and KCC activities. The abnormal red cell behaviour was similar to that in the commonest genotype of SCD, HbSS, in which the level of mutated Hb is considerably higher. Although activities of all three K+ transporters also correlated with the level of HbS-Oman, there was no association between transport phenotype and disease severity. The super sickling behaviour of HbS-Oman may obviate the need for solute loss and red cell dehydration to encourage Hb polymerisation, required in other SCD genotypes. Disease severity was reduced by concurrent α thalassaemia, as observed in other SCD genotypes, and represents an obvious genetic marker for prognostic tests of severity in young SCD patients of the HbA/S-Oman genotype.
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Affiliation(s)
| | - Yasser Wali
- Department of Child Health, Sultan Qaboos University, Muscat, Oman
| | - Maha Al Awadi
- Department of Genetics, Sultan Qaboos University, Muscat, Oman
| | | | - David C Rees
- Department of Paediatric Haematology, King's College Hospital, King's College London School of Medicine, London, UK
| | - John N Brewin
- Department of Paediatric Haematology, King's College Hospital, King's College London School of Medicine, London, UK
| | - Anke Hannemann
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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7
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Hannemann A, Cytlak UM, Rees DC, Tewari S, Gibson JS. Effects of 5-hydroxymethyl-2-furfural on the volume and membrane permeability of red blood cells from patients with sickle cell disease. J Physiol 2014; 592:4039-49. [PMID: 25015917 PMCID: PMC4198013 DOI: 10.1113/jphysiol.2014.277681] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/04/2014] [Indexed: 12/14/2022] Open
Abstract
The heterocyclic aldehyde 5-hydroxymethyl-2-furfural (5HMF) interacts allosterically with the abnormal form of haemoglobin (Hb), HbS, in red blood cells (RBCs) from patients with sickle cell disease (SCD), thereby increasing oxygen affinity and decreasing HbS polymerization and RBC sickling during hypoxia. We hypothesized that should 5HMF also inhibit the main cation pathways implicated in the dehydration of RBCs from SCD patients - the deoxygenation-induced cation pathway (Psickle), the Ca(2+)-activated K(+) channel (the Gardos channel) and the K(+)-Cl(-) cotransporter (KCC) - it would have a synergistic effect in protection against sickling, directly through interacting with HbS, and indirectly through maintaining hydration and reducing [HbS]. This study was therefore designed to investigate the effects of 5HMF on RBC volume and K(+) permeability in vitro. 5HMF markedly reduced the deoxygenation-induced dehydration of RBCs whether in response to maintained deoxygenation or to cyclical deoxygenation/re-oxygenation. 5HMF was found to inhibit Psickle, an effect which correlated with its effects on sickling. Deoxygenation-induced activation of the Gardos channel and exposure of phosphatidylserine were also inhibited, probably indirectly via reduced entry of Ca(2+) through the Psickle pathway. Effects of 5HMF on KCC were more modest with a slight inhibition in N-ethylmaleimide (NEM, 1 mm)-treated RBCs and stimulation in RBCs untreated with NEM. These findings support the hypothesis that 5HMF may also be beneficial through effects on RBC ion and water homeostasis.
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Affiliation(s)
- Anke Hannemann
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Urszula M Cytlak
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David C Rees
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, London, UK
| | - Sanjay Tewari
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, London, UK
| | - John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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8
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Hannemann A, Cytlak UMC, Gbotosho OT, Rees DC, Tewari S, Gibson JS. Effects of o-vanillin on K⁺ transport of red blood cells from patients with sickle cell disease. Blood Cells Mol Dis 2014; 53:21-6. [PMID: 24594314 PMCID: PMC4039999 DOI: 10.1016/j.bcmd.2014.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 01/24/2014] [Indexed: 01/26/2023]
Abstract
Aromatic aldehydes like o-vanillin were designed to reduce the complications of sickle cell disease (SCD) by interaction with HbS, to reduce polymerisation and RBC sickling. Present results show that o-vanillin also directly affects RBC membrane permeability. Both the K(+)-Cl(-) cotransporter (KCC) and the Ca(2+)-activated K(+) channel (or Gardos channel) were inhibited with IC50 of about 0.3 and 1 mM, respectively, with activities almost completely abolished by 5 mM. Similar effects were observed in RBCs treated with the thiol reacting reagent N-ethylmaleimide or with the Ca(2+) ionophore A23187, to circumvent any action via HbS polymerisation. The deoxygenation-induced cation conductance (sometimes termed P(sickle)) was partially inhibited, whilst deoxygenation-induced exposure of phosphatidylserine was completely abrogated. Na(+)/K(+) pump activity was also reduced. Notwithstanding, o-vanillin stimulated K(+) efflux through an unidentified pathway and resulted in reduction in cell volume (as measured by wet weight-dry weight). These actions are relevant to understanding how aromatic aldehydes may affect RBC membrane permeability per se as well as HbS polymerisation and thereby inform design of compounds most efficacious in ameliorating the complications of SCD.
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Affiliation(s)
- A Hannemann
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom
| | - U M C Cytlak
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom
| | - O T Gbotosho
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom
| | - D C Rees
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, Denmark Hill, London, SE5 9RS, United Kingdom
| | - S Tewari
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, Denmark Hill, London, SE5 9RS, United Kingdom
| | - J S Gibson
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom.
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Inhibitors of second messenger pathways and Ca(2+)-induced exposure of phosphatidylserine in red blood cells of patients with sickle cell disease. Pflugers Arch 2013; 466:1477-85. [PMID: 24158429 PMCID: PMC4062833 DOI: 10.1007/s00424-013-1343-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 08/25/2013] [Accepted: 08/25/2013] [Indexed: 01/09/2023]
Abstract
The present work investigates the contribution of various second messenger systems to Ca2+-induced phosphatidylserine (PS) exposure in red blood cells (RBCs) from sickle cell disease (SCD) patients. The Ca2+ dependence of PS exposure was confirmed using the Ca2+ ionophore bromo-A23187 to clamp intracellular Ca2+ over 4 orders of magnitude in high or low potassium-containing (HK or LK) saline. The percentage of RBCs showing PS exposure was significantly increased in LK over HK saline. This effect was reduced by the Gardos channel inhibitors, clotrimazole and charybdotoxin. Nevertheless, although Ca2+ loading in the presence of an outwardly directed electrochemical gradient for K+ stimulated PS exposure, substantial exposure still occurred in HK saline. Under the conditions used inhibitors of other second messenger systems (ABT491, quinacrine, acetylsalicylic acid, 3,4-dichloroisocoumarin, GW4869 and zVAD-fmk) did not inhibit the relationship between [Ca2+] and PS exposure. Inhibitors of phospholipase A2, cyclooxygenase, platelet-activating factor, sphingomyelinase and caspases, therefore, were without effect on Ca2+-induced PS exposure in RBCs, incubated in either HK or LK saline.
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10
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Weiss E, Cytlak UM, Rees DC, Osei A, Gibson JS. Deoxygenation-induced and Ca(2+) dependent phosphatidylserine externalisation in red blood cells from normal individuals and sickle cell patients. Cell Calcium 2011; 51:51-6. [PMID: 22197026 DOI: 10.1016/j.ceca.2011.10.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 09/29/2011] [Accepted: 10/23/2011] [Indexed: 01/03/2023]
Abstract
Phosphatidylserine (PS) is usually confined to the inner leaflet of the red blood cell (RBC) membrane. It may become externalised in various conditions, however, notably in RBCs from patients with sickle cell disease (SCD) where exposed PS may contribute to anaemic and ischaemic complications. PS externalisation requires both inhibition of the aminophospholipid translocase (or flippase) and activation of the scramblase. Both may follow from elevation of intracellular Ca(2+). Flippase inhibition occurs at low [Ca(2+)](i), about 1μM, but [Ca(2+)](i) required for scrambling is reported to be much higher (around 100μM). In this work, FITC-labelled lactadherin and FACS were used to measure externalised PS, with [Ca(2+)](i) altered using bromo-A23187 and EGTA/Ca(2+) mixtures. Two components of Ca(2+)-induced scrambling were apparent, of high (EC(50) 1.8±0.3μM) and low (306±123μM) affinity, in RBCs from normal individuals and the commonest SCD genotypes, HbSS and HbSC. The high affinity component was lost in the presence of unphysiologically high [Mg(2+)] but was unaffected by high K(+) (90mM) or vanadate (1mM). The high affinity component accounted for PS scrambling in ≥2/3rd RBCs. It is likely to be most significant in vivo and may be involved in the pathophysiology of SCD or other conditions involving eryptosis.
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Affiliation(s)
- Erwin Weiss
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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11
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Role of calcium in phosphatidylserine externalisation in red blood cells from sickle cell patients. Anemia 2010; 2011:379894. [PMID: 21490763 PMCID: PMC3065920 DOI: 10.1155/2011/379894] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 08/23/2010] [Indexed: 01/15/2023] Open
Abstract
Phosphatidylserine exposure occurs in red blood cells (RBCs) from sickle cell disease (SCD) patients and is increased by deoxygenation. The mechanisms responsible remain unclear. RBCs from SCD patients also have elevated cation permeability, and, in particular, a deoxygenation-induced cation conductance which mediates Ca2+ entry, providing an obvious link with phosphatidylserine exposure. The role of Ca2+ was investigated using FITC-labelled annexin. Results confirmed high phosphatidylserine exposure in RBCs from SCD patients increasing upon deoxygenation. When deoxygenated, phosphatidylserine exposure was further elevated as extracellular [Ca2+] was increased. This effect was inhibited by dipyridamole, intracellular Ca2+ chelation, and Gardos channel inhibition. Phosphatidylserine exposure was reduced in high K+ saline. Ca2+ levels required to elicit phosphatidylserine exposure were in the low micromolar range. Findings are consistent with Ca2+ entry through the deoxygenation-induced pathway (Psickle), activating the Gardos channel. [Ca2+] required for phosphatidylserine scrambling are in the range achievable in vivo.
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12
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Bogdanova A, Goede JS, Weiss E, Bogdanov N, Bennekou P, Bernhardt I, Lutz HU. Cryohydrocytosis: increased activity of cation carriers in red cells from a patient with a band 3 mutation. Haematologica 2009; 95:189-98. [PMID: 20015879 DOI: 10.3324/haematol.2009.010215] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Cryohydrocytosis is an inherited dominant hemolytic anemia characterized by mutations in a transmembrane segment of the anion exchanger (band 3 protein). Transfection experiments performed in Xenopus oocytes suggested that these mutations may convert the anion exchanger into a non-selective cation channel. The present study was performed to characterize so far unexplored ion transport pathways that may render erythrocytes of a single cryohydrocytosis patient cation-leaky. DESIGN AND METHODS Cold-induced changes in cell volume were monitored using ektacytometry and density gradient centrifugation. Kinetics, temperature and inhibitor-dependence of the cation and water movements in the cryohydrocytosis patient's erythrocytes were studied using radioactive tracers and flame photometry. Response of the membrane potential of the patient's erythrocyte membrane to the presence of ionophores and blockers of anion and cation channels was assessed. RESULTS In the cold, the cryohydrocytosis patient's erythrocytes swelled in KCl-containing, but not in NaCl-containing or KNO(3)-containing media indicating that volume changes were mediated by an anion-coupled cation transporter. In NaCl-containing medium the net HOE-642-sensitive Na(+)/K(+) exchange prevailed, whereas in KCl-containing medium swelling was mediated by a chloride-dependent K(+) uptake. Unidirectional K(+) influx measurements showed that the patient's cells have abnormally high activities of the cation-proton exchanger and the K(+),Cl(-) co-transporter, which can account for the observed net movements of cations. Finally, neither chloride nor cation conductance in the patient's erythrocytes differed from that of healthy donors. Conclusions These results suggest that cross-talk between the mutated band 3 and other transporters might increase the cation permeability in cryohydrocytosis.
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Affiliation(s)
- Anna Bogdanova
- Zurich Center for Integrative, Human Physiology, University of Zurich, Winterthurerstr 260, CH 8057 Zurich, Switzerland.
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13
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Adragna NC, Lauf PK. K-Cl cotransport function and its potential contribution to cardiovascular disease. ACTA ACUST UNITED AC 2007; 14:135-46. [PMID: 17949953 DOI: 10.1016/j.pathophys.2007.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
K-Cl cotransport is the coupled electroneutral movement of K and Cl ions carried out by at least four protein isoforms, KCC1-4. These transporters belong to the SLC12A family of coupled cotransporters and, due to their multiple functions, play an important role in the maintenance of cellular homeostasis. Significant information exists on the overall function of these transporters, but less is known about the role of the specific isoforms. Most functional studies were done on K-Cl cotransport fluxes without knowing the molecular details, and only recently attention has been paid to the isoforms and their individual contribution to the fluxes. This review summarizes briefly and updates the information on the overall functions of this transporter, and offers some ideas on its potential contribution to the pathophysiological basis of cardiovascular disease. By virtue of its properties and the cellular ionic distribution, K-Cl cotransport participates in volume regulation of the nucleated and some enucleated cells studied thus far. One of the hallmarks in cardiovascular disease is the inability of the organism to maintain water and electrolyte balance in effectors and/or target tissues. Oxidative stress is another compounding factor in cardiovascular disease and of great significance in our modern life styles. Several functions of the transporter are modulated by oxidative stress, which in turn may cause the transporter to operate in either "overdrive" with the purpose to counteract homeostatic changes, or not to respond at all, again setting the stage for pathological changes leading to cardiovascular disease. Intracellular Mg, a second messenger, acts as an inhibitor of K-Cl cotransport and plays a crucial role in regulating the activity of protein kinases and phosphatases, which, in turn, regulate a myriad of cellular functions. Although the role of Mg in cardiovascular disease has been dealt with for several decades, this chapter is evolving nowadays at a faster pace and the relationships between Mg, K-Cl cotransport, and cardiovascular disease is an area that awaits further experimentation. We envision that further studies on the role of K-Cl cotransport, and ideally on its specific isoforms, in mammalian cells will add missing links and help to understand the cellular mechanisms involved in the pathophysiology of cardiovascular disease.
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Affiliation(s)
- Norma C Adragna
- Cell Biophysics Group, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, United States; Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, United States
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Characterization of the deoxyhemoglobin binding site on human erythrocyte band 3: implications for O2 regulation of erythrocyte properties. Blood 2007; 111:932-8. [PMID: 17942752 DOI: 10.1182/blood-2007-07-100180] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Band 3, the major protein of the human erythrocyte membrane, associates with multiple metabolic, ion transport, and structural proteins. Functional studies demonstrate that the oxygenation state of the erythrocyte regulates cellular properties performed by these and/or related proteins. Because deoxyhemoglobin, but not oxyhemoglobin, binds band 3 reversibly with high affinity, these observations raise the hypothesis that hemoglobin might regulate erythrocyte properties through its reversible, oxygenation-dependent association with band 3. To explore this hypothesis, we have characterized the binding site of deoxyHb on human erythrocyte band 3. We report that (1) deoxyHb binds to residues 12-23 of band 3; (2) mutation of residues on either side of this sequence greatly enhances affinity of deoxyHb for band 3, suggesting that evolution of a higher affinity interaction would have been possible had it been beneficial for survival; (3) Hb does not bind to 2 other sequences in band 3 despite their high sequence homology to residues 12-23, and (4) the Hb binding site on band 3 lies proximal to binding sites for glycolytic enzymes, band 4.1 and ankyrin, suggesting possible mechanisms through which multifarious erythrocyte properties might be regulated by the oxygenation state of the cell.
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