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Petkova-Kirova P, Murciano N, Iacono G, Jansen J, Simionato G, Qiao M, Van der Zwaan C, Rotordam MG, John T, Hertz L, Hoogendijk AJ, Becker N, Wagner C, Von Lindern M, Egee S, Van den Akker E, Kaestner L. The Gárdos Channel and Piezo1 Revisited: Comparison between Reticulocytes and Mature Red Blood Cells. Int J Mol Sci 2024; 25:1416. [PMID: 38338693 PMCID: PMC10855361 DOI: 10.3390/ijms25031416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 02/12/2024] Open
Abstract
The Gárdos channel (KCNN4) and Piezo1 are the best-known ion channels in the red blood cell (RBC) membrane. Nevertheless, the quantitative electrophysiological behavior of RBCs and its heterogeneity are still not completely understood. Here, we use state-of-the-art biochemical methods to probe for the abundance of the channels in RBCs. Furthermore, we utilize automated patch clamp, based on planar chips, to compare the activity of the two channels in reticulocytes and mature RBCs. In addition to this characterization, we performed membrane potential measurements to demonstrate the effect of channel activity and interplay on the RBC properties. Both the Gárdos channel and Piezo1, albeit their average copy number of activatable channels per cell is in the single-digit range, can be detected through transcriptome analysis of reticulocytes. Proteomics analysis of reticulocytes and mature RBCs could only detect Piezo1 but not the Gárdos channel. Furthermore, they can be reliably measured in the whole-cell configuration of the patch clamp method. While for the Gárdos channel, the activity in terms of ion currents is higher in reticulocytes compared to mature RBCs, for Piezo1, the tendency is the opposite. While the interplay between Piezo1 and Gárdos channel cannot be followed using the patch clamp measurements, it could be proved based on membrane potential measurements in populations of intact RBCs. We discuss the Gárdos channel and Piezo1 abundance, interdependencies and interactions in the context of their proposed physiological and pathophysiological functions, which are the passing of small constrictions, e.g., in the spleen, and their active participation in blood clot formation and thrombosis.
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Affiliation(s)
- Polina Petkova-Kirova
- Institute of Neurobiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
- Department of Biochemistry, Saarland University, 66123 Saarbrücken, Germany
| | - Nicoletta Murciano
- Nanion Technologies, 80339 Munich, Germany; (N.M.); (M.G.R.); (N.B.)
- Theoretical Medicine and Biosciences, Campus University Hospital, Saarland University, 66421 Homburg, Germany; (J.J.); (M.Q.); (L.H.)
| | - Giulia Iacono
- Department of Hematopoiesis, Sanquin Research, 1066 CX Amsterdam, The Netherlands; (G.I.); (C.V.d.Z.); (A.J.H.); (M.V.L.); (E.V.d.A.)
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Julia Jansen
- Theoretical Medicine and Biosciences, Campus University Hospital, Saarland University, 66421 Homburg, Germany; (J.J.); (M.Q.); (L.H.)
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
| | - Greta Simionato
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
- Department of Experimental Surgery, Campus University Hospital, Saarland University, 66421 Homburg, Germany
| | - Min Qiao
- Theoretical Medicine and Biosciences, Campus University Hospital, Saarland University, 66421 Homburg, Germany; (J.J.); (M.Q.); (L.H.)
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
| | - Carmen Van der Zwaan
- Department of Hematopoiesis, Sanquin Research, 1066 CX Amsterdam, The Netherlands; (G.I.); (C.V.d.Z.); (A.J.H.); (M.V.L.); (E.V.d.A.)
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1007 MB Amsterdam, The Netherlands
| | | | - Thomas John
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
| | - Laura Hertz
- Theoretical Medicine and Biosciences, Campus University Hospital, Saarland University, 66421 Homburg, Germany; (J.J.); (M.Q.); (L.H.)
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
| | - Arjan J. Hoogendijk
- Department of Hematopoiesis, Sanquin Research, 1066 CX Amsterdam, The Netherlands; (G.I.); (C.V.d.Z.); (A.J.H.); (M.V.L.); (E.V.d.A.)
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Nadine Becker
- Nanion Technologies, 80339 Munich, Germany; (N.M.); (M.G.R.); (N.B.)
| | - Christian Wagner
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Marieke Von Lindern
- Department of Hematopoiesis, Sanquin Research, 1066 CX Amsterdam, The Netherlands; (G.I.); (C.V.d.Z.); (A.J.H.); (M.V.L.); (E.V.d.A.)
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Stephane Egee
- Biological Station Roscoff, Sorbonne University, CNRS, UMR8227 LBI2M, F-29680 Roscoff, France;
- Laboratory of Excellence GR-Ex, F-75015 Paris, France
| | - Emile Van den Akker
- Department of Hematopoiesis, Sanquin Research, 1066 CX Amsterdam, The Netherlands; (G.I.); (C.V.d.Z.); (A.J.H.); (M.V.L.); (E.V.d.A.)
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Campus University Hospital, Saarland University, 66421 Homburg, Germany; (J.J.); (M.Q.); (L.H.)
- Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany (T.J.); (C.W.)
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Monedero Alonso D, Pérès L, Hatem A, Bouyer G, Egée S. The Chloride Conductance Inhibitor NS3623 Enhances the Activity of a Non-selective Cation Channel in Hyperpolarizing Conditions. Front Physiol 2021; 12:743094. [PMID: 34707512 PMCID: PMC8543036 DOI: 10.3389/fphys.2021.743094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 09/13/2021] [Indexed: 12/29/2022] Open
Abstract
Handbooks of physiology state that the strategy adopted by red blood cells (RBCs) to preserve cell volume is to maintain membrane permeability for cations at its minimum. However, enhanced cation permeability can be measured and observed in specific physiological and pathophysiological situations such as in vivo senescence, storage at low temperature, sickle cell anemia and many other genetic defects affecting transporters, membrane or cytoskeletal proteins. Among cation pathways, cation channels are able to dissipate rapidly the gradients that are built and maintained by the sodium and calcium pumps. These situations are very well-documented but a mechanistic understanding of complex electrophysiological events underlying ion transports is still lacking. In addition, non-selective cation (NSC) channels present in the RBC membrane have proven difficult to molecular identification and functional characterization. For instance, NSC channel activity can be elicited by Low Ionic Strength conditions (LIS): the associated change in membrane potential triggers its opening in a voltage dependent manner. But, whereas this depolarizing media produces a spectacular activation of NSC channel, Gárdos channel-evoked hyperpolarization's have been shown to induce sodium entry through a pathway thought to be conductive and termed Pcat. Using the CCCP method, which allows to follow fast changes in membrane potential, we show here (i) that hyperpolarization elicited by Gárdos channel activation triggers sodium entry through a conductive pathway, (ii) that chloride conductance inhibition unveils such conductive cationic conductance, (iii) that the use of the specific chloride conductance inhibitor NS3623 (a derivative of Neurosearch compound NS1652), at concentrations above what is needed for full anion channel block, potentiates the non-selective cation conductance. These results indicate that a non-selective cation channel is likely activated by the changes in the driving force for cations rather than a voltage dependence mechanism per se.
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Affiliation(s)
- David Monedero Alonso
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Laurent Pérès
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Aline Hatem
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Guillaume Bouyer
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Stéphane Egée
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
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Mechanistic ion channel interactions in red cells of patients with Gárdos channelopathy. Blood Adv 2021; 5:3303-3308. [PMID: 34468723 DOI: 10.1182/bloodadvances.2020003823] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 04/07/2021] [Indexed: 12/25/2022] Open
Abstract
In patients with Gárdos channelopathy (p.R352H), an increased concentration of intracellular Ca2+ was previously reported. This is a surprising finding because the Gárdos channel (KCa3.1) is a K+ channel. Here, we confirm the increased intracellular Ca2+ for patients with the KCa3.1 mutation p.S314P. Furthermore, we provide the concept of KCa3.1 activity resulting in a flickering of red blood cell (RBC) membranepotential, which activates the CaV2.1 channel allowing Ca2+ to enter the RBC. Activity of the nonselective cation channel Piezo1 modulates the aforementioned interplay in away that a closed Piezo1 is in favor of the KCa3.1-CaV2.1 interaction. In contrast, Piezo1 openings compromise the membrane potential flickering, thus limiting the activity of CaV2.1. With the compound NS309, we mimic a gain-of-function mutation of KCa3.1. Assessing the RBC Ca2+ response by Fluo-4-based flow cytometry and by measuring the membrane potential using the Macey-Bennekou-Egée method, we provide data that support the concept of the KCa3.1/CaV2.1/Piezo1 interplay as a partial explanation for an increased number of high Ca2+ RBCs. With the pharmacological inhibition of KCa3.1 (TRAM34 and Senicapoc), CaV2.1 (ω-agatoxin TK), and Piezo1 (GsMTx-4), we could project the NS309 behavior of healthy RBCs to the RBCs of Gárdos channelopathy patients.
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Ugurel E, Kisakurek ZB, Aksu Y, Goksel E, Cilek N, Yalcin O. Calcium/protein kinase C signaling mechanisms in shear-induced mechanical responses of red blood cells. Microvasc Res 2021; 135:104124. [PMID: 33359148 DOI: 10.1016/j.mvr.2020.104124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 12/24/2022]
Abstract
Red blood cell (RBC) deformability has vital importance for microcirculation in the body, as RBCs travel in narrow capillaries under shear stress. Deformability can be defined as a remarkable cell ability to change shape in response to an external force which allows the cell to pass through the narrowest blood capillaries. Previous studies showed that RBC deformability could be regulated by Ca2+/protein kinase C (PKC) signaling mechanisms due to the phosphorylative changes in RBC membrane proteins by kinases and phosphatases. We investigated the roles of Ca2+/PKC signaling pathway on RBC mechanical responses and impaired RBC deformability under continuous shear stress (SS). A protein kinase C inhibitor Chelerythrine, a tyrosine phosphatase inhibitor Calpeptin, and a calcium channel blocker Verapamil were applied into human blood samples in 1 micromolar concentration. Samples with drugs were treated with or without 3 mM Ca2+. A shear stress at 5 Pa level was applied to each sample continuously for 300 s. RBC deformability was measured by a laser-assisted optical rotational cell analyzer (LORRCA) and was calculated as the change in elongation index (EI) of RBC upon a range of shear stress (SS, 0.3-50 Pa). RBC mechanical stress responses were evaluated before and after continuous SS through the parameterization of EI-SS curves. The drug administrations did not produce any significant alterations in RBC mechanical responses when they were applied alone. However, the application of the drugs together with Ca2+ substantially increased RBC deformability compared to calcium alone. Verapamil significantly improved Ca2+-induced impairments of deformability both before and after 5 Pa SS exposure (p < 0.0001). Calpeptin and Chelerythrine significantly ameliorated impaired deformability only after continuous SS (p < 0.05). Shear-induced improvements of deformability were conserved by the drug administrations although shear-induced deformability was impaired when the drugs were applied with calcium. The blocking of Ca2+ channel by Verapamil improved impaired RBC mechanical responses independent of the SS effect. The inhibition of tyrosine phosphatase and protein kinase C by Calpeptin and Chelerythrine, respectively, exhibited ameliorating effects on calcium-impaired deformability with the contribution of shear stress. The modulation of Ca2+/PKC signaling pathway could regulate the mechanical stress responses of RBCs when cells are under continuous SS exposure. Shear-induced improvements in the mechanical properties of RBCs by this signaling mechanism could facilitate RBC flow in the microcirculation of pathophysiological disorders, wherein Ca2+ homeostasis is disturbed and RBC deformability is reduced.
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Affiliation(s)
- Elif Ugurel
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey; Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | | | - Yasemin Aksu
- School of Medicine, Koç University, Istanbul, Turkey
| | - Evrim Goksel
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey; Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Neslihan Cilek
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey; Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Ozlem Yalcin
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey; Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey; School of Medicine, Koç University, Istanbul, Turkey.
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5
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Kaestner L, Bogdanova A, Egee S. Calcium Channels and Calcium-Regulated Channels in Human Red Blood Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:625-648. [PMID: 31646528 DOI: 10.1007/978-3-030-12457-1_25] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Free Calcium (Ca2+) is an important and universal signalling entity in all cells, red blood cells included. Although mature mammalian red blood cells are believed to not contain organelles as Ca2+ stores such as the endoplasmic reticulum or mitochondria, a 20,000-fold gradient based on a intracellular Ca2+ concentration of approximately 60 nM vs. an extracellular concentration of 1.2 mM makes Ca2+-permeable channels a major signalling tool of red blood cells. However, the internal Ca2+ concentration is tightly controlled, regulated and maintained primarily by the Ca2+ pumps PMCA1 and PMCA4. Within the last two decades it became evident that an increased intracellular Ca2+ is associated with red blood cell clearance in the spleen and promotes red blood cell aggregability and clot formation. In contrast to this rather uncontrolled deadly Ca2+ signals only recently it became evident, that a temporal increase in intracellular Ca2+ can also have positive effects such as the modulation of the red blood cells O2 binding properties or even be vital for brief transient cellular volume adaptation when passing constrictions like small capillaries or slits in the spleen. Here we give an overview of Ca2+ channels and Ca2+-regulated channels in red blood cells, namely the Gárdos channel, the non-selective voltage dependent cation channel, Piezo1, the NMDA receptor, VDAC, TRPC channels, CaV2.1, a Ca2+-inhibited channel novel to red blood cells and i.a. relate these channels to the molecular unknown sickle cell disease conductance Psickle. Particular attention is given to correlation of functional measurements with molecular entities as well as the physiological and pathophysiological function of these channels. This view is in constant progress and in particular the understanding of the interaction of several ion channels in a physiological context just started. This includes on the one hand channelopathies, where a mutation of the ion channel is the direct cause of the disease, like Hereditary Xerocytosis and the Gárdos Channelopathy. On the other hand it applies to red blood cell related diseases where an altered channel activity is a secondary effect like in sickle cell disease or thalassemia. Also these secondary effects should receive medical and pharmacologic attention because they can be crucial when it comes to the life-threatening symptoms of the disease.
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Affiliation(s)
- Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany. .,Experimental Physics, Saarland University, Saarbrücken, Germany.
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty and the Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Stephane Egee
- CNRS, UMR8227 LBI2M, Sorbonne Université, Roscoff, France.,Laboratoire d'Excellence GR-Ex, Paris, France
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Impact of a 10 km running trial on eryptosis, red blood cell rheology, and electrophysiology in endurance trained athletes: a pilot study. Eur J Appl Physiol 2019; 120:255-266. [PMID: 31776697 DOI: 10.1007/s00421-019-04271-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Blood rheology is a key determinant of blood flow and tissue perfusion. There are still large discrepancies regarding the effects of an acute running exercise on blood rheological properties and red blood cell (RBC) physiology. We investigated the effect of a 10 km running trial on markers of blood rheology and RBC physiology in endurance trained athletes. METHODS Blood was sampled before and after the exercise to measure lactate and glucose, hematological and hemorheological parameters (blood viscosity, RBC deformability, and aggregation), eryptosis markers (phosphatidylserine and CD47 exposure, RBC reactive oxygen species), RBC-derived microparticles (RBC-MPs), and RBC electrophysiological activity. Weight was measured before and after exercise. Peripheral oxygen saturation and heart rate were monitored before and during the trial. RESULTS Blood lactate and glucose levels increased after exercise and subjects significantly lost weight. All athletes experienced a significant fall in oxygen saturation. Mean corpuscular volume (MCV) was increased from 95.1 ± 3.2 to 96.0 ± 3.3 and mean corpuscular hemoglobin concentration (MCHC) decreased after exercise suggesting a slight RBC rehydration. Exercise increased RBC deformability from 0.344 ± 0.04 to 0.378 ± 0.07, decreased RBC aggregates strength and blood viscosity, while hematocrit (Hct) remained unaffected. While RBC electrophysiological recording suggested a modulation in RBC calcium content and/or chloride conductance, eryptosis markers and RBC-MPs were not modified by the exercise. CONCLUSION A 10 km acute running exercise had no effect on RBC senescence and membrane blebbing. In contrast, this exercise increased RBC deformability, probably through rehydration process which resulted in a decrease in blood viscosity.
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Kaestner L, Wang X, Hertz L, Bernhardt I. Voltage-Activated Ion Channels in Non-excitable Cells-A Viewpoint Regarding Their Physiological Justification. Front Physiol 2018; 9:450. [PMID: 29755371 PMCID: PMC5934782 DOI: 10.3389/fphys.2018.00450] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/10/2018] [Indexed: 01/27/2023] Open
Affiliation(s)
- Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Xijia Wang
- Laboratory of Biophysics, Saarland University, Saarbrücken, Germany
| | - Laura Hertz
- Medical Faculty, Institute for Molecular Cell Biology, Saarland University, Homburg, Germany
| | - Ingolf Bernhardt
- Laboratory of Biophysics, Saarland University, Saarbrücken, Germany
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Kucherenko YV, Lang F. Inhibitory effect of furosemide on non-selective voltage-independent cation channels in human erythrocytes. Cell Physiol Biochem 2012; 30:863-75. [PMID: 22907543 DOI: 10.1159/000341464] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Furosemide, a loop diuretic inhibiting the renal tubular Na(+),K(+),2Cl(-) cotransporter, has been shown to decrease cytosolic Ca(2+) concentration ([Ca(2+)](i)) in platelets and erythrocytes. [Ca(2+)](i) in erythrocytes is a function of Ca(2+) permeable cation channels. Activation of those channels e.g. by energy depletion or oxidative stress leads to increase of [Ca(2+)](i), which in turn triggers eryptosis, a suicidal erythrocyte death characterized by cell membrane scrambling. The present study was performed to explore whether furosemide influences the cation channels and thus influences eryptosis. METHODS Cation channel activity was determined by whole-cell patch clamp, [Ca(2+)](i) utilizing Fluo3 fluorescence and annexin V binding to estimate cell membrane scrambling with phosphatidylserine exposure. RESULTS A 45 min exposure to furosemide (10 and 100 µM) slightly, but significantly decreased cation channel activity and [Ca(2+)](i) in human erythrocytes drawn from healthy individuals. ATP-depletion (> 3 hours, +37°C, 6 mM ionosine and 6 mM iodoacetic acid) enhanced the non-selective cation channel activity, increased [Ca(2+)](i) and triggered cell membrane scrambling, effects significantly blunted by furosemide (10 - 100 µM). Oxidative stress by exposure to tert-butylhydroperoxide (0.1 -1 mM) similarly enhanced the non-selective cation channels activity, increased [Ca(2+)](i) and triggered cell membrane scrambling, effects again significantly blunted by furosemide (10 - 100 µM). CONCLUSIONS The present study shows for the first time that the loop diuretic furosemide applied at micromolar concentrations (10 - 100 µM) inhibits non-selective cation channel activity in and eryptosis of human erythrocytes.
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Affiliation(s)
- Yuliya V Kucherenko
- Department of Physiology Institute I, Eberhard-Karls Universität Tübingen, Tübingen, Germany
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9
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Seear RV, Lew VL. IKCa agonist (NS309)-elicited all-or-none dehydration response of human red blood cells is cell-age dependent. Cell Calcium 2011; 50:444-8. [DOI: 10.1016/j.ceca.2011.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Revised: 07/04/2011] [Accepted: 07/11/2011] [Indexed: 11/24/2022]
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Simonsen LO, Harbak H, Bennekou P. Passive transport pathways for Ca(2+) and Co(2+) in human red blood cells. (57)Co(2+) as a tracer for Ca(2+) influx. Blood Cells Mol Dis 2011; 47:214-25. [PMID: 21962619 DOI: 10.1016/j.bcmd.2011.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 08/29/2011] [Indexed: 01/06/2023]
Abstract
The passive transport of calcium and cobalt and their interference were studied in human red cells using (45)Ca and (57)Co as tracers. In ATP-depleted cells, with the ATP concentration reduced to about 1μM, the progress curve for (45)Ca uptake at 1mM rapidly levels off with time, consistent with a residual Ca-pump activity building up at increasing [Ca(T)](c) to reach at [Ca(T)](c) about 5μmol(lcells)(-1) a maximal pump rate that nearly countermands the passive Ca influx, resulting in a linear net uptake at a low level. In ATP-depleted cells treated with vanadate, supposed to cause Ca-pump arrest, a residual pump activity is still present at high [Ca(T)](c). Moreover, vanadate markedly increases the passive Ca(2+) influx. The residual Ca-pump activity in ATP-depleted cells is fuelled by breakdown of the large 2,3-DPG pool, rate-limited by the sustainable ATP-turnover at about 40-50μmol(lcells)(-1)h(-1). The apparent Ca(2+) affinity of the Ca-pump appears to be markedly reduced compared to fed cells. The 2,3-DPG breakdown can be prevented by inhibition of the 2,3-DPG phosphatase by tetrathionate, and under these conditions the (45)Ca uptake is markedly increased and linear with time, with the unidirectional Ca influx at 1mM Ca(2+) estimated at 50-60μmol(lcells)(-1)h(-1). The Ca influx increases with the extracellular Ca(2+) concentration with a saturating component, with K(½(Ca)) about 0.3mM, plus a non-saturating component. From (45)Ca-loaded, ATP-depleted cells the residual Ca-pump can also be detected as a vanadate- and tetrathionate-sensitive efflux. The (45)Ca efflux is markedly accelerated by external Ca(2+), both in control cells and in the presence of vanadate or tetrathionate, suggesting efflux by carrier-mediated Ca/Ca exchange. The (57)Co uptake is similar in fed cells and in ATP-depleted cells (exposed to iodoacetamide), consistent with the notion that Co(2+) is not transported by the Ca-pump. The transporter is thus neither SH-group nor ATP or phosphorylation dependent. The (57)Co uptake shows several similarities with the (45)Ca uptake in ATP-depleted cells supplemented with tetrathionate. The uptake is linear with time, and increases with the cobalt concentration with a saturating component, with J(max) about 16μmol(lcells)(-1)h(-1) and K(½(Co)) about 0.1mM, plus a non-saturating component. The (57)Co and (45)Ca uptake shows mutual inhibition, and at least the stochastic Ca(2+) influx is inhibited by Co(2+). The (57)Co and (45)Ca uptake are both insensitive to the 1,4-dihydropyridine Ca-channel blocker nifedipine, even at 100μM. The (57)Co uptake is increased at high negative membrane potentials, indicating that the uptake is at least partially electrogenic. The (57)Co influx amounts to about half the (45)Ca influx in ATP-depleted cells. It is speculated that the basal Ca(2+) and Co(2+) uptake could be mediated by a common transporter, probably with a channel-like and a carrier-mediated component, and that (57)Co could be useful as a tracer for at least the channel-like Ca(2+) entry pathway in red cells, since it is not itself transported by the Ca-pump and, moreover, is effectively buffered in the cytosol by binding to hemoglobin, without interfering with Ca(2+) buffering. The molecular identity of the putative common transporter(s) remains to be defined.
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Affiliation(s)
- Lars Ole Simonsen
- Department of Biology, University of Copenhagen, August Krogh Building, Denmark
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11
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Kucherenko YV, Lang F. Inhibition of cation channels in human erythrocytes by spermine. J Membr Biol 2010; 237:93-106. [PMID: 21063869 DOI: 10.1007/s00232-010-9310-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 10/20/2010] [Indexed: 11/30/2022]
Abstract
In erythrocytes, spermine concentration decreases gradually with age, which is paralleled by increases of cytosolic Ca²+ concentration, with subsequent cell shrinkage and cell membrane scrambling. Cytosolic Ca²+ was estimated from fluo-3 fluorescence, cell volume from forward scatter, cell membrane scrambling from annexin V binding and cation channel activity with whole-cell patch-clamp in human erythrocytes. Extracellular spermine exerted a dual effect on erythrocyte survival. At 200 μM spermine blunted the increase of intracellular Ca²+, cell shrinkage and annexin V binding following 48 h exposure of cells at +37 °C. In contrast, short exposure (10-30 min) of cells to 2 mM spermine was accompanied by increased cytosolic Ca²+ and annexin binding. Intracellular addition of spermine at subphysiological concentration (0.2 μM) significantly decreased the conductance of monovalent cations (Na+, K+, NMDG+) and of Ca²+. Moreover, spermine (0.2 μM) blunted the stimulation of voltage-independent cation channels by Cl⁻ removal. Spermine (0.2 and 200 μM) added to the extracellular bath solution similarly inhibited the cation conductance in Cl⁻-containing bath solution. The effect of 0.2 μM spermine, but not the effect of 200 μM, was rapidly reversible. Acute addition (250 μM) of a naphthyl acetyl derivative of spermine (200 μM) again significantly decreased basal cation conductance in NaCl bath solution and inhibited voltage-independent cation channels. Spermine is a powerful regulator of erythrocyte cation channel cytosolic Ca²+ activity and, thus, cell survival.
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Affiliation(s)
- Yuliya V Kucherenko
- Department of Physiology Institute I, Eberhard-Karls Universität Tübingen, 72076 Tübingen, Germany
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Swietach P, Tiffert T, Mauritz JMA, Seear R, Esposito A, Kaminski CF, Lew VL, Vaughan-Jones RD. Hydrogen ion dynamics in human red blood cells. J Physiol 2010; 588:4995-5014. [PMID: 20962000 DOI: 10.1113/jphysiol.2010.197392] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Our understanding of pH regulation within red blood cells (RBCs) has been inferred mainly from indirect experiments rather than from in situ measurements of intracellular pH (pH(i)). The present work shows that carboxy-SNARF-1, a pH fluorophore, when used with confocal imaging or flow cytometry, reliably reports pH(i) in individual, human RBCs, provided intracellular fluorescence is calibrated using a 'null-point' procedure. Mean pH(i) was 7.25 in CO(2)/HCO(3)(-)-buffered medium and 7.15 in Hepes-buffered medium, and varied linearly with extracellular pH (slope of 0.77). Intrinsic (non-CO(2)/HCO(3)(-)-dependent) buffering power, estimated in the intact cell (85 mmol (l cell)(-1) (pH unit)(-1) at resting pH(i)), was somewhat higher than previous estimates from cell lysates (50-70 mmol (l cell)(-1) (pH unit)(-1)). Acute displacement of pH(i) (superfusion of weak acids/bases) triggered rapid pH(i) recovery. This was mediated via membrane Cl(-)/HCO(3)(-) exchange (the AE1 gene product), irrespective of whether recovery was from an intracellular acid or base load, and with no evident contribution from other transporters such as Na(+)/H(+) exchange. H(+)-equivalent flux through AE1 was a linear function of [H(+)](i) and reversed at resting pH(i), indicating that its activity is not allosterically regulated by pH(i), in contrast to other AE isoforms. By simultaneously monitoring pH(i) and markers of cell volume, a functional link between membrane ion transport, volume and pH(i) was demonstrated. RBC pH(i) is therefore tightly regulated via AE1 activity, but modulated during changes of cell volume. A comparable volume-pH(i) link may also be important in other cell types expressing anion exchangers. Direct measurement of pH(i) should be useful in future investigations of RBC physiology and pathology.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Burdon Sanderson Cardiac Science Centre, Parks Road, Oxford OX1 3PT, UK.
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Kucherenko YV, Bhavsar SK, Grischenko VI, Fischer UR, Huber SM, Lang F. Increased cation conductance in human erythrocytes artificially aged by glycation. J Membr Biol 2010; 235:177-89. [PMID: 20526772 DOI: 10.1007/s00232-010-9265-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 05/12/2010] [Indexed: 12/21/2022]
Abstract
Excessive glucose concentrations foster glycation and thus premature aging of erythrocytes. The present study explored whether glycation-induced erythrocyte aging is paralleled by features of suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface and cell shrinkage. Both are triggered by increases of cytosolic Ca(2+) concentration ([Ca(2+)](i)), which may result from activation of Ca(2+) permeable cation channels. Glycation was accomplished by exposure to high glucose concentrations (40 and 100 mM), phosphatidylserine exposure estimated from annexin binding, cell shrinkage from decrease of forward scatter, and [Ca(2+)](i) from Fluo3-fluorescence in analysis via fluorescence-activated cell sorter. Cation channel activity was determined by means of whole-cell patch clamp. Glycation of total membrane proteins, immunoprecipitated TRPC3/6/7, and immunoprecipitated L-type Ca(2+) channel proteins was estimated by Western blot testing with polyclonal antibodies used against advanced glycation end products. A 30-48-h exposure of the cells to 40 or 100 mM glucose in Ringer solution (at 37 degrees C) significantly increased glycation of membrane proteins, hemoglobin (HbA(1c)), TRPC3/6/7, and L-type Ca(2+) channel proteins, enhanced amiloride-sensitive, voltage-independent cation conductance, [Ca(2+)](i), and phosphatidylserine exposure, and led to significant cell shrinkage. Ca(2+) removal and addition of Ca(2+) chelator EGTA prevented the glycation-induced phosphatidylserine exposure and cell shrinkage after glycation. Glycation-induced erythrocyte aging leads to eryptosis, an effect requiring Ca(2+) entry from extracellular space.
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Affiliation(s)
- Yuliya V Kucherenko
- Department of Physiology, Institute I, Eberhard-Karls-Universität Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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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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Effects of elevated intracellular calcium on the osmotic fragility of human red blood cells. Cell Calcium 2009; 47:29-36. [PMID: 19954845 DOI: 10.1016/j.ceca.2009.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 11/03/2009] [Indexed: 11/20/2022]
Abstract
High throughput methodologies that measure the distribution of osmotic fragilities in red blood cell populations have enabled the investigation of dynamic changes in red cell homeostasis and membrane permeability in health and disease. The common assumption in the interpretation of dynamic changes in osmotic fragility curves is that left or right shifts reflect a decreased or increased hydration state of the cells, respectively, allowing direct inferences on membrane transport from osmotic fragility measurements. However, the assumed correlation between shifts in osmotic fragility and hydration state has never been directly explored, and may prove invalid in certain conditions. We investigated here whether this correlation holds for red cells exposed to elevated intracellular calcium. The results showed that elevated cell calcium causes a progressive increase in osmotic fragility with minimal contribution from cell hydration (<8%). Loss of membrane area by the release of 160+/-40nm diameter (mean+/-SD) vesicles is shown to be a major contributor, but may not account for the full non-hydration component. The rest must reflect a specific calcium-induced lytic vulnerability of the membrane causing rupture before the cells attain their maximal spherical volumes. The implications of these findings are discussed.
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