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

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.

1993 ◽  
Vol 265 (1) ◽  
pp. C99-C105 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein

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)


1988 ◽  
Vol 255 (3) ◽  
pp. C331-C339 ◽  
Author(s):  
P. K. Lauf

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)


1989 ◽  
Vol 257 (1) ◽  
pp. C58-C64 ◽  
Author(s):  
K. H. Ryu ◽  
N. C. Adragna ◽  
P. K. Lauf

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.


1972 ◽  
Vol 136 (6) ◽  
pp. 1666-1671 ◽  
Author(s):  
Traute-Heidi Anderson ◽  
Joan Roethle ◽  
Robert Auerbach

Adult mice injected with a sheep red blood cell hemolysate supernatant fraction were found to have a severely reduced responsiveness to subsequent immunization with sheep red blood cells. The induced unresponsiveness was found to be specific, as tested by reciprocal experiments involving horse and sheep erythrocyte preparations. The tolerogenic material did not appear to be immunogenic.


1984 ◽  
Vol 247 (1) ◽  
pp. C120-C123 ◽  
Author(s):  
P. B. Dunham ◽  
B. E. Farquharson ◽  
R. L. Bratcher

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.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Yuncheng Man ◽  
Debnath Maji ◽  
Ran An ◽  
Sanjay Ahuja ◽  
Jane A Little ◽  
...  

Alterations in the deformability of red blood cells (RBCs), occurring in hemolytic blood disorders such as sickle cell disease (SCD), contributes to vaso-occlusion and disease pathophysiology. However, there are few...


1999 ◽  
Vol 277 (2) ◽  
pp. H508-H514 ◽  
Author(s):  
Charmaine B. S. Henry ◽  
Brian R. Duling

The endothelial cell glycocalyx influences blood flow and presents a selective barrier to movement of macromolecules from plasma to the endothelial surface. In the hamster cremaster microcirculation, FITC-labeled Dextran 70 and larger molecules are excluded from a region extending almost 0.5 μm from the endothelial surface into the lumen. Red blood cells under normal flow conditions are excluded from a region extending even farther into the lumen. Examination of cultured endothelial cells has shown that the glycocalyx contains hyaluronan, a glycosaminoglycan which is known to create matrices with molecular sieving properties. To test the hypothesis that hyaluronan might be involved in establishing the permeation properties of the apical surface glycocalyx in vivo, hamster microvessels in the cremaster muscle were visualized using video microscopy. After infusion of one of several FITC-dextrans (70, 145, 580, and 2,000 kDa) via a femoral cannula, microvessels were observed with bright-field and fluorescence microscopy to obtain estimates of the anatomic diameters and the widths of fluorescent dextran columns and of red blood cell columns (means ± SE). The widths of the red blood cell and dextran exclusion zones were calculated as one-half the difference between the bright-field anatomic diameter and the width of the red blood cell column or dextran column. After 1 h of treatment with active Streptomyces hyaluronidase, there was a significant increase in access of 70- and 145-kDa FITC-dextrans to the space bounded by the apical glycocalyx, but no increase in access of the red blood cells or in the anatomic diameter in capillaries, arterioles, and venules. Hyaluronidase had no effect on access of FITC-Dextrans 580 and 2,000. Infusion of a mixture of hyaluronan and chondroitin sulfate after enzyme treatment reconstituted the glycocalyx, although treatment with either molecule separately had no effect. These results suggest that cell surface hyaluronan plays a role in regulating or establishing permeation of the apical glycocalyx to macromolecules. This finding and our prior observations suggest that hyaluronan and other glycoconjugates are required for assembly of the matrix on the endothelial surface. We hypothesize that hyaluronidase creates a more open matrix, enabling smaller dextran molecules to penetrate deeper into the glycocalyx.


2018 ◽  
Vol 42 (3) ◽  
pp. 151-157 ◽  
Author(s):  
Antony P McNamee ◽  
Kieran Richardson ◽  
Jarod Horobin ◽  
Lennart Kuck ◽  
Michael J Simmonds

Introduction: Accumulating evidence demonstrates that subhaemolytic mechanical stresses, typical of circulatory support, induce physical and biochemical changes to red blood cells. It remains unclear, however, whether cell age affects susceptibility to these mechanical forces. This study thus examined the sensitivity of density-fractionated red blood cells to sublethal mechanical stresses. Methods: Red blood cells were isolated and washed twice, with the least and most dense fractions being obtained following centrifugation (1500 g × 5 min). Red blood cell deformability was determined across an osmotic gradient and a range of shear stresses (0.3–50 Pa). Cell deformability was also quantified before and after 300 s exposure to shear stresses known to decrease (64 Pa) or increase (10 Pa) red blood cell deformability. The time course of accumulated sublethal damage that occurred during exposure to 64 Pa was also examined. Results: Dense red blood cells exhibited decreased capacity to deform when compared with less dense cells. Cellular response to mechanical stimuli was similar in trend for all red blood cells, independent of density; however, the magnitude of impairment in cell deformability was exacerbated in dense cells. Moreover, the rate of impairment in cellular deformability, induced by 64 Pa, was more rapid for dense cells. Relative improvement in red blood cell deformability, due to low-shear conditioning (10 Pa), was consistent for both cell populations. Conclusion: Red blood cell populations respond differently to mechanical stimuli: older (more dense) cells are highly susceptible to sublethal mechanical trauma, while cell age (density) does not appear to alter the magnitude of improved cell deformability following low-shear conditioning.


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