Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens

1993 ◽  
Vol 265 (1) ◽  
pp. C99-C105 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Rat Kidney ◽  
Striking Increase ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Membrane Antigens ◽  
Low K ◽  
Kinetics Of

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics of Na-Li exchange in high and low K sheep red blood cells

1989 ◽  
Vol 257 (1) ◽  
pp. C58-C64 ◽  
Author(s):  
K. H. Ryu ◽  
N. C. Adragna ◽  
P. K. Lauf
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Types ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Ping Pong ◽  
Order Of Magnitude ◽  
Low K ◽  
Kinetics Of ◽  
System Operating

The kinetic parameters and transport mechanism of Na-Li exchange were studied in both low K (LK) and high K (HK) sheep red blood cells with cellular Na [( Na]i) and Li concentrations [( Li]i) adjusted by the nystatin technique (Nature New Biol. 244: 47-49, 1973 and J. Physiol. Lond. 283: 177-196, 1978). Maximum velocities (Vm) for Li fluxes and half-activation constants (K1/2) for Li and Na of the Na-Li exchanger were determined. The K1/2 values for both Li and Na appeared to be similar in both cell types, although they were about two to three times lower on the inside than on the outside of the membrane. Furthermore, the K1/2 values for Li were at least an order of magnitude smaller than those for Na, suggesting substantial affinity differences for these two cations. The Vm values for Li fluxes, on the other hand, appear to be lower in HK than in LK cells. When Na and Li fluxes were measured simultaneously, a trans stimulatory effect by Na on Li fluxes was observed. From measurements of Li influx at different concentrations of external Li and different [Na]i, the ratio of the apparent Vm to the apparent external Li affinity was calculated to be independent of [Na]i for both types of sheep red blood cells. Similar trans effects of external Na were observed on Li efflux at varying [Li]i. These results are expected for a system operating by a “ping-pong” mechanism.

Rat kidney Na-K pumps incorporated into low-K+ sheep red blood cell membranes are stimulated by anti-Lp antibody

1992 ◽  
Vol 263 (5) ◽  
pp. C1007-C1014 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
J. S. Munzer ◽  
J. R. Silvius ◽  
R. Blostein
Keyword(s):  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Rat Kidney ◽  
Molecular Entity ◽  
Sheep Red Blood Cells ◽  
K Cells ◽  
High K ◽  
Low K

A genetic dimorphism of sheep red blood cells characterized by differences in the intracellular K+ concentration of mature red blood cells (low-K+ or high-K+ cells) reflects differences in their Na-K pumps and is known to be linked to the ML blood group system. We investigated the relationship of Na-K pumps in red blood cells from sheep of the low-K+ phenotype with an antigen, Lp, that is restricted to low-K+ cells. Anti-Lp antibody stimulates the Na-K pumps in these cells presumably by relieving inhibition of the pumps by Lp. The questions addressed were as follows: is Lp a molecular entity distinct from pumps and, if so, can it interact with pumps of exogenous origin? Rat kidney Na-K pumps were incorporated by fusion of microsomes into either low-K+ or high-K+ sheep red blood cells. The activity of the exogenous kidney pumps was distinguished from that of the endogenous red blood cell pumps by the low sensitivity of rodent pumps to ouabain. Anti-Lp stimulated by > 50% rat kidney pumps incorporated into immature low-K+ sheep cells. This indicates that Lp is a distinct molecular entity free to dissociate from endogenous pumps and inhibit exogenous pumps. Anti-Lp did not stimulate kidney pumps incorporated into mature low-K+ cells but did stimulate kidney pumps following in vitro maturation of microsome fused reticulocytes, probably reflecting restriction of lateral movement of pumps and antigens by the cytoskeleton in mature cells.

Volume and anion dependency of ouabain-resistant K-Rb fluxes in sheep red blood cells

1988 ◽  
Vol 255 (3) ◽  
pp. C331-C339 ◽  
Author(s):  
P. K. Lauf
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Types ◽  
Sheep Red Blood Cells ◽  
K Cells ◽  
High K ◽  
Before And After ◽  
Volume Response ◽  
Altered Cell ◽  
Low K

The effect of six different anions on the volume response of ouabain-resistant K transport was systematically studied at extracellular pH (pHo) = 7.4 in sheep red blood cells of both low and high K genotype before and after treatment with the sulfhydryl (SH) reagent N-ethylmaleimide (NEM). In methanesulfonate (CH3SO3), both the apparent Rb permeability (P(app)Rb), calculated from ouabain-resistant Rb influx), and K permeability (PK, calculated from the rate constants of ouabain-resistant zero-trans K efflux, 0k(OR)K) were volume independent and close to 10(-10) cm/s for both cell types, but in Cl, Br, I, SCN, and NO3 they were significantly different in low and high K cells with altered cell volumes. Thus, in 15% osmotically shrunken low K cells, P(app)Rb) and PK were similar regardless of the anions present, but upon 10-15% swelling, they increased to approximately 4-6 X 10(-9) cm/s in Br and 2 X 10(-9) cm/s in Cl and also increased with comparatively small increments in I, SCN, and NO3. Treatment with NEM enhanced both P(app)Rb) and PK, particularly in shrunken low K cells, to approximately 10(-8) cm/s in Br and Cl but not in I, SCN, and NO3. In shrunken or isotonic high K cells, P(app)Rb) and PK were close to 10(-10) cm/s in all anions except for SCN. Swelling and/or NEM increased PK and P(app)Rb) in Cl and Br only two- to threefold.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in number of Na-K pumps on low-K+ sheep reticulocytes during maturation is modulated by Lp antigen

1994 ◽  
Vol 266 (5) ◽  
pp. C1173-C1181 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Group Antigen ◽  
Cell Maturation ◽  
Alpha Subunit ◽  
Ouabain Binding ◽  
High K ◽  
Antigen System ◽  
Low K

The number of the Na-K pumps on sheep red blood cells declines markedly during cell maturation. In addition, in red blood cells of the low-K+ (LK) phenotype, there is an increase during maturation in the affinity of the pumps for intracellular K+. This increase does not occur in cells of the high-K+ (HK) phenotype. This HK/LK polymorphism is associated with the M/L blood group antigen system. The Lp antigen, which is on only LK cells, promotes the increase in affinity for K+ [Am. J. Physiol. 265 (Cell Physiol. 34): C99-C105, 1993]. Mature LK cells have fewer pumps than mature HK cells. The present study shows that the Lp antigen also promotes the loss of pumps in LK cells. The evidence was that modification of the Lp antigen of immature LK red blood cells either with anti-Lp antibody or by trypsinization diminished the loss of pumps during culture in vitro (numbers determined from [3H]ouabain binding). Confirmation came from demonstration of the decline during maturation of the amount of the alpha-subunit of the Na-K pump (measured by immunoblotting), which was also retarded by pretreatment with anti-Lp or trypsin. Comparisons of the relative amounts of Lp antigen on immature and mature LK cells showed that there is little decline in number of antigens during maturation. Therefore there is an increase in the antigen-to-pump ratio during maturation even though an association between pumps and antigens is necessary for the loss of pumps.

Stimulation of Na+-K+ pump in sheep red blood cells by heteroimmune anti-sheep red cell antibodies

1984 ◽  
Vol 247 (1) ◽  
pp. C120-C123 ◽  
Author(s):  
P. B. Dunham ◽  
B. E. Farquharson ◽  
R. L. Bratcher
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Red Cell ◽  
Sheep Red Blood Cells ◽  
L Cells ◽  
High K ◽  
First Time ◽  
Low K ◽  
K Transport ◽  
Stimulation Of

In the HK-LK polymorphism of sheep red blood cells, alloimmune antiserum against the L antigen on LK cells is known to stimulate the Na+-K+ pump in low K+ (LK) cells, but alloimmune antiserum against the M antigen of high K+ (HK) cells does not. We have shown for the first time that heteroimmune antibodies against sheep red blood cells raised in mice can stimulate the pump. Heteroimmune antibodies against both LK(L) cells and HK(M) cells stimulated active K+ transport in LK cells. Furthermore heteroimmune antibodies against LK(L) cells also stimulated the pump in HK cells. As expected, alloimmune and heteroimmune antibodies acted at different sites in stimulating transport in LK cells.

scholarly journals In vitro antioxidant effects of Trigonella foenum graecum (L.) Fenugreek seed extract on sheep red blood cells

2012 ◽  
Vol 6 (38) ◽  
pp. 5119-5127 ◽  
Author(s):  
Dinakaran Vasudevan ◽  
Sridharan Subhashree ◽  
Periyasamy Latha ◽  
Sudha Rani Sankaramoorthy
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Seed Extract ◽  
Trigonella Foenum Graecum ◽  
Fenugreek Seed ◽  
Sheep Red Blood Cells ◽  
Trigonella Foenum Graecum L ◽  
Antioxidant Effects

scholarly journals Kinetics of Cl-dependent K fluxes in hyposmotically swollen low K sheep erythrocytes.

1991 ◽  
Vol 97 (2) ◽  
pp. 173-193 ◽  
Author(s):  
E Delpire ◽  
P K Lauf
Keyword(s):  
Red Blood Cells ◽  
Kinetic Study ◽  
Kinetic Parameters ◽  
Blood Cells ◽  
Red Cells ◽  
Maximal Velocity ◽  
Temperature Dependent ◽  
Low K ◽  
Kinetics Of ◽  
External K

A detailed kinetic study of K:Cl cotransport in hyposmotically swollen low K sheep red blood cells was carried out to characterize the nature of the outwardly poised carrier. The kinetic parameters were determined from the rate of K efflux and influx under zero-K-trans conditions in red cells with cellular K altered by the nystatin method and with different extracellular K or Rb concentrations. Although apparent affinities for efflux and influx were quite similar, the maximal velocity for K efflux was approximately two times greater than for influx. Furthermore, at thermodynamic equilibrium (i.e., when the ion product of K and Cl within the cell was equal to that outside) a temperature-dependent net K efflux was observed, approaching zero only when the external product reached approximately two times the internal product. The binding order of the ions to the transporter was asymmetric, being ordered outside (Cl binding first, followed by K) and random inside. K efflux but not influx was trans-inhibited by KCl. Trans inhibition of K efflux was used to verify the order of binding outside: trans inhibition by external Cl occurred in the absence of external K, but not vice versa. Thus K:Cl cotransport is kinetically asymmetric in hyposmotically swollen low K sheep red cells.

scholarly journals Calibration, Selection and Identifiability Analysis of a Mathematical Model of the in vitro Erythropoiesis in Normal and Perturbed Contexts

2018 ◽  
Author(s):  
Ronan Duchesne ◽  
Anissa Guillemin ◽  
Fabien Crauste ◽  
Olivier Gandrillon
Keyword(s):  
Mathematical Model ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Identifiability Analysis ◽  
The Past ◽  
Parameter Variations ◽  
Linear Ode ◽  
Kinetics Of

AbstractThe in vivo erythropoiesis, which is the generation of mature red blood cells in the bone marrow of whole organisms, has been described by a variety of mathematical models in the past decades. However, the in vitro erythropoiesis, which produces red blood cells in cultures, has received much less attention from the modelling community. In this paper, we propose the first mathematical model of in vitro erythropoiesis. We start by formulating different models and select the best one at fitting experimental data of in vitro erythropoietic differentiation. It is based on a set of linear ODE, describing 3 hypothetical populations of cells at different stages of differentiation. We then compute confidence intervals for all of its parameters estimates, and conclude that our model is fully identifiable. Finally, we use this model to compute the effect of a chemical drug called Rapamycin, which affects all states of differentiation in the culture, and relate these effects to specific parameter variations. We provide the first model for the kinetics of in vitro cellular differentiation which is proven to be identifiable. It will serve as a basis for a model which will better account for the variability which is inherent to experimental protocol used for the model calibration.

Several cation transporters and volume regulation in high-K dog red blood cells

1991 ◽  
Vol 260 (3) ◽  
pp. C589-C597 ◽  
Author(s):  
H. Fujise ◽  
I. Yamada ◽  
M. Masuda ◽  
Y. Miyazawa ◽  
E. Ogawa ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation ◽  
Cation Composition ◽  
Influx Rate ◽  
Physiological Conditions ◽  
High K ◽  
Dependent Transport ◽  
Low K ◽  
K Transport

Normal dog red blood cells lack the Na-K pump, and their cation composition is low K and high Na (LK). Recently, a dog was found with red blood cells containing high K and low Na concentrations (HK) due to the existence of the Na-K pump. In the present study, cation transport and volume regulation in HK cells were compared with those of LK cells. HK cells showed not only Rb influx through a Na-K pump, but also Rb influx through a Cl-dependent K transporter. The Rb influx rate through the Na-K pump was 0.65-1.44 mmol.l cells-1.h-1 in Cl and 1.75-2.24 mmol.l cells-1.h-1 in NO3, in HK cells, but only trace activities are found in LK cells. In HK cells, the Rb influx rate through Cl-dependent K transport was 0.36-0.96 mmol.l cells-1.h-1, and it was enhanced in swollen cells but vanished in shrunken cells. In LK cells, the transport was evident only in swollen cells. The original volume of swollen HK cells was restored by water extrusion promoted by Cl-dependent transport. The Na-Ca exchange transporter, which works as a volume regulator in LK cells, functioned in HK cells only when they were loaded with Na. Hence, the exchange transporter is latent in HK cells under physiological conditions. Moreover, the exchange transporter could restore the cell volume in swollen and Na-loaded HK cells. However, the volume in HK cells was still larger than that in LK cells, while the Na-Ca exchange transporter was working.(ABSTRACT TRUNCATED AT 250 WORDS)

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