KCl Cotransport in HbAA and HbSS Red Cells: Activation by Intracellular Acidity and Disappearance During Maturation

Ellory, J. Clive; Hall, Andrew C.; Ody, S A; Poli-de-Figueiredo, Carlos Eduardo; Chalder, S.; Stuart, J.

doi:10.1007/978-1-4684-5985-2_5

Cited by 11 publications

(7 citation statements)

References 17 publications

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“…4). Since internal pH will change along with external, either or both may be responsible for the stimulation of transport: the present results do not enable us to distinguish between these possibilities, but previous work in human cells was consistent with a major role for internal pH (Ellory, Hall, Ody, de Figueiredos, Chalder & Stuart, 1991). The pharmacological properties of the equine cotransporter are also similar to those of K+-Cl-cotransport in other species.…”

Section: Effect Of Reduction In Oxygen Tension On K+fluxessupporting

confidence: 64%

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Gibson

Godart²,

Jc³

et al. 1994

Experimental Physiology

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SUMMARYPotassium transport was measured in equine red blood cells, using 8fRb+ influx as a convenient assay. A significant component of volume-and pH-sensitive K+-Cl-cotransport to the overall K+ flux was observed in all blood samples studied, although fluxes were variable between animals, and within individuals when measured at intervals over a period of weeks. The aryloxyacetic acid [(dihydroindenyl)oxy]alkanoic acid (DIOA), at a final concentration of 100jUM, inhibited most (>95 %) of the Cl--dependent K+ flux, and DIOA sensitivity was therefore used to define the activity of the K+-Cl-cotransporter. K+-Cl-cotransport was also sensitive to protein phosphatase inhibition with calyculin A or okadaic acid, with inhibition constants of 9 + 1 nm for calyculin and about 100 nm for okadaic acid. Peak fluxes were observed at an extemal pH of 6-7-7 0, with inhibition at higher and lower values. Volumesensitive K+ fluxes assayed in autologous plasma, controlled for osmolality, pH and potassium concentration, were significantly lower (28 + 8 % of control values, n = 6) than those measured in saline. This inhibition was mimicked by the culture medium RPMI, but disappeared following dialysis of the plasma. Phosphate (5 6 mM) inhibited volume-sensitive K+ fluxes by 48 + 2 %, n = 3; no significant effect was observed by increasing external magnesium concentrations to 0.5 or 2 mm. Thus, inhibition by RPMI, but not that by plasma, may be due to phosphate. Finally, volume-and pH-sensitive K+ fluxes were sensitive to oxygen tension and were abolished reversibly by equilibrating solutions with nitrogen, as opposed to air. Use of solutions equilibrated with different values of PO, may account for some of the variability in equine red blood cell KCI fluxes. The importance of these observations to equine red blood cell homeostasis and haemodynamics is discussed.

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Section: Effect Of Reduction In Oxygen Tension On K+fluxessupporting

confidence: 64%

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Gibson

Godart²,

Jc³

et al. 1994

Experimental Physiology

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“…A third possibility, that the volume-sensitive K¤ influx in deoxygenated LK sheep red cells was mediated through a K¤ transport pathway other than KCl cotransport, was investigated in the experiment shown in Fig. 2 (Ellory, Hall, Ody, deFigueiredos, Chalder & Stuart, 1991). We therefore examined the effects of oxygenation upon H¤-stimulated K¤ influx in LK sheep red cells.…”

Section: Resultsmentioning

confidence: 99%

Oxygen‐dependent K⁺ fluxes in sheep red cells

Campbell

Gibson

1998

The Journal of Physiology

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This study was designed to investigate the O2 dependence of K+ influx in sheep red cells. Influx was determined using 86Rb+ as a tracer for K+; glass tonometers coupled to a gas mixing pump were used to equilibrate cell samples to the requisite oxygen tension (PO2). Both volume‐ and H+‐stimulated K+ influxes in low potassium‐containing (LK) sheep red cells were approximately doubled on equilibration with O2 relative to influxes measured in N2. O2‐dependent influxes were abolished when Cl− was replaced with NO3−, consistent with mediation by the KCl cotransporter. At pH 7, PO2 required for half‐maximal stimulation was 56 ± 1 mmHg (mean ± s.e.m., 3 sheep) for the O2‐dependent component of K+ influx: thus PO2 values over the physiological range affected K+ influx. K+ influx in fully deoxygenated sheep red cells showed substantial volume and H+ sensitivity. These residual components in N2 were also Cl− dependent, indicating that the KCl cotransporter of LK sheep red cells was active in the absence of O2. Volume‐sensitive K+ influxes in high potassium‐containing (HK) sheep red cells responded in a similar way to those in cells from LK sheep, although much smaller in magnitude, showing that intracellular [K+] had no significant effect on the O2 dependence of the cotransporter. Intracellular [Mg2+] ([Mg2+]i) was altered by incubating sheep red cells with A23187 (20 μM) and different values of extracellular [Mg2+] ([Mg2+]o). Total [Mg2+]i was determined by atomic absorption spectroscopy and free [Mg2+]i from [Mg2+]o and the Donnan ratio. Total [Mg2+]i was 1.29 ± 0.08 mM (mean ± s.e.m., n= 5), similar to that reported in the literature. Estimates of free [Mg2+]i showed an increase from 0.39 ± 0.05 in oxygenated cells to 0.52 ± 0.04 mM (mean ± s.e.m., n= 5; P < 0.05) in deoxygenated ones. Finally, although K+ influxes were altered by pharmacological loading or depletion of cells with Mg2+, the free [Mg2+]i required to affect influxes significantly was outside the physiological range. Results are difficult to reconcile with PO2 modulating KCl cotransport activity directly via changes in free [Mg2+]i or [Mg2+‐ATP]i.

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“…Among the most well-known is the transferrin receptor. The number of copies per cell of Na,K-ATPase, Na/glycine transporter (Blostein and Grafova, 1987), nucleoside transporter, and K-Cl cotransporter (Canessa et al, 1987; Ellory et al, 1991) is reduced and renders the cell less energy-demanding and more stable.…”

Section: Changes In Activity Of Ion Transporter During Rbc Senescencementioning

confidence: 99%

Mechanisms tagging senescent red blood cells for clearance in healthy humans

2013

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This review focuses on the analysis and evaluation of the diverse senescence markers suggested to prime red blood cells (RBC) for clearance in humans. These tags develop in the course of biochemical and structural alterations accompanying RBC aging, as the decrease of activities of multiple enzymes, the gradual accumulation of oxidative damage, the loss of membrane in form of microvesicles, the redistribution of ions and alterations in cell volume, density, and deformability. The actual tags represent the penultimate galactosyl residues, revealed by desialylation of glycophorins, or the aggregates of the anion exchanger (band 3 protein) to which anti-galactose antibodies bind in the first and anti-band 3 naturally occurring antibodies (NAbs) in the second case. While anti-band 3 NAbs bind to the carbohydrate-free portion of band 3 aggregates in healthy humans, induced anti-lactoferrin antibodies bind to the carbohydrate-containing portion of band 3 and along with anti-band 3 NAbs may accelerated clearance of senescent RBC in patients with anti-neutrophil cytoplasmic antibodies (ANCA). Exoplasmically accessible phosphatidylserine (PS) and the alterations in the interplay between CD47 on RBC and its receptor on macrophages, signal regulatory protein alpha (SIRPalpha protein), were also reported to induce erythrocyte clearance. We discuss the relevance of each mechanism and analyze the strength of the data.

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KCl Cotransport in HbAA and HbSS Red Cells: Activation by Intracellular Acidity and Disappearance During Maturation

Cited by 11 publications

References 17 publications

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Oxygen‐dependent K⁺ fluxes in sheep red cells

Mechanisms tagging senescent red blood cells for clearance in healthy humans

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KCl Cotransport in HbAA and HbSS Red Cells: Activation by Intracellular Acidity and Disappearance During Maturation

Cited by 11 publications

References 17 publications

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Modulation of K(+)‐Cl‐ cotransport in equine red blood cells

Oxygen‐dependent K+ fluxes in sheep red cells

Mechanisms tagging senescent red blood cells for clearance in healthy humans

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Product

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Oxygen‐dependent K⁺ fluxes in sheep red cells