Some red blood cell phenomena for the curious

Hoffman, Joseph F.

doi:10.1016/j.bcmd.2004.01.002

Cited by 12 publications

(10 citation statements)

References 48 publications

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“…The physical origin of this effect and the reason behind the success of the effective temperature model is not yet known. The phenomenon of shape changes of RBC in response to changes in ATP levels is also well documented (Wong, 1999;Lim et al, 2002); here again, the reason for the dependence on ATP is not known (Hoffman, 2001(Hoffman, , 2004Nakao, 2002).…”

Section: Introductionmentioning

confidence: 73%

“…In addition to enhancing the membrane fluctuations, ATPinduced transient defects of the spectrin network are also important in determining the average shape of RBC (Hoffman, 2001(Hoffman, , 2004Nakao, 2002). The intimate experimental correlation between the amplitude of membrane fluctuations and overall cell shape was demonstrated in Fricke et al (1986).…”

Section: Atp-driven Steady-state Rbc Shapementioning

confidence: 97%

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Red Blood Cell Membrane Fluctuations and Shape Controlled by ATP-Induced Cytoskeletal Defects

Gov

Safran

2005

Biophysical Journal

275

346

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We show theoretically how adenosine 5'-triphosphate (ATP)-induced dynamic dissociations of spectrin filaments (from each other and from the membrane) in the cytoskeleton network of red blood cells (RBC) can explain in a unified manner both the measured fluctuation amplitude as well as the observed shape transformations as a function of intracellular ATP concentration. Static defects can be induced by external stresses such as those present when RBCs pass through small capillaries. We suggest that the partially freed actin at these defect sites may explain the activation of the CFTR membrane-bound protein and the subsequent release of ATP by RBCs subjected to deformations. Our theoretical predictions can be tested by experiments that measure the correlation between variations in the binding of actin to spectrin, the activity of CFTR, and the amount of ATP released.

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Section: Introductionmentioning

confidence: 73%

Section: Atp-driven Steady-state Rbc Shapementioning

confidence: 97%

Red Blood Cell Membrane Fluctuations and Shape Controlled by ATP-Induced Cytoskeletal Defects

Gov

Safran

2005

Biophysical Journal

275

346

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“…Another type of memory is perhaps associated with a study by Paul LaCelle that has been quoted before (in ref. 25). LaCelle reported that, when a biconcave disk drawn into a cigar shape in a pipette was then split (without hemolysis) into two fragments, each fragment formed a biconcave disk upon extrusion from the pipette.…”

Section: Significancementioning

confidence: 99%

Biconcave shape of human red-blood-cell ghosts relies on density differences between the rim and dimple of the ghost's plasma membrane

Hoffman

2016

Proc. Natl. Acad. Sci. U.S.A.

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The shape of the human red blood cell is known to be a biconcave disk. It is evident from a variety of theoretical work that known physical properties of the membrane, such as its bending energy and elasticity, can explain the red-blood-cell biconcave shape as well as other shapes that red blood cells assume. But these analyses do not provide information on the underlying molecular causes. This paper describes experiments that attempt to identify some of the underlying determinates of cell shape. To this end, red-blood-cell ghosts were made by hypotonic hemolysis and then reconstituted such that they were smooth spheres in hypo-osmotic solutions and smooth biconcave discs in iso-osmotic solutions. The spherical ghosts were centrifuged onto a coated coverslip upon which they adhered. When the attached spheres were changed to biconcave discs by flushing with an iso-osmotic solution, the ghosts were observed to be mainly oriented in a flat alignment on the coverslip. This was interpreted to mean that, during centrifugation, the spherical ghosts were oriented by a dense band in its equatorial plane, parallel to the centrifugal field. This appears to be evidence that the difference in the densities between the rim and the dimple regions of red blood cells and their ghosts may be responsible for their biconcave shape.red-blood-cell ghosts | membrane/cytoskeletal complex | biconcave discs | spheres T his paper is concerned with identifying a possible determinant responsible for the biconcave shape of human red blood cells (RBCs). Although RBCs ("globules") were first discovered in the latter part of the 17th century (1), it was not until 1827 that they were definitively shown by Hodgkin and Lister (2) to be biconcave discs. Since that time much has been learned about RBC composition (3), in particular identification of its membrane/cytoskeletal (M/CS) elements and structure (4). Our particular interest focuses on whether the symmetry of the M/CS is the same or different between the cell's dimple and rim regions. If different, such an observation might provide insight into the structural basis for the cell's biconcave shape. The approach used was to centrifuge hypotonically sphered red-blood-cell ghosts onto a coverslip upon which they adhered. The question was, what was the orientation of the stuck ghosts when they were made into biconcave discs upon exposure to an isotonic solution?It is important to mention that others have used a quite different approach to understand the basis for the red blood cell's biconcave shape. These types of studies have used solutions of theoretical models that are mainly based on the red blood cell's known physical parameters, such as the membrane's bending energy and elastic properties (e.g., 5-11) in addition to lateral inhomogeneities in the M/CS (12). These analyses have remarkably generated not only the cell's biconcave shape but also many other types of shapes that the cells are known to assume. Thus, they provide insight into and understanding of the types of forces that characteri...

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“…The normal shape of erythrocytes is an equilibrium state between two opposing shape changes(echinocytic and stomatocytic) maintained by many factors of which organization of the membrane skeleton, ATP levels, asymmetric lipid distributions, cholesterol/phospholipids ratio, pH gradient and the presence or absence of surface active agents are prominent 19,24,25) . It was observed in this study that both NaF and PLA2 induced echinocytic change in erythrocytes whereas PLD, SMase and CPZ caused stomatocytic transformations.…”

Section: Discussionmentioning

confidence: 99%

Erythrocyte Shape Change Prevents Plasmodium falciparum Invasion

et al. 2007

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Normal erythrocytes have biconcave discoid shape that presents large surface area with higher cell surface to volume ratio than that of spherical shape. This appears to allow membrane internalization required for Plasmodium falciparum (Pf) invasion into erythrocytes. Indeed abnormal erythrocyte shape with decreased surface area to volume ratio such as hereditary spherocytosis limits invasion of the parasite. In the present study, using several agents to induce erythrocyte shape changes, we examined whether echinocytic shape change with membrane projections in opposite direction to membrane internalizations and/or stomatocytic shape change with decreased surface area to volume ratio that would be required for internalization, prevent Pf invasion. Having microscopically confirmed echinocytic and/or stomatocytic shape changes and also measured extensibility using an ektacytometer of the treated cells, subsequent Pf invasion assay was performed and parasitaemia determined. Both sodium flouride (NaF) and phospholipase A 2 (PLA 2) induced echinocytic change whereas phospholipase D (PLD), sphingomyelinase (SMase) and chlorpromazine (CPZ) caused stomatocytic change with decreased extensibility of erythrocytes. In both situations, Pf invasion was prevented, indicating that biconcave discoid shape of normal erythrocytes with high surface to volume ratio is required for membrane internalization when Pf invades into erythrocytes.

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Some red blood cell phenomena for the curious

Cited by 12 publications

References 48 publications

Red Blood Cell Membrane Fluctuations and Shape Controlled by ATP-Induced Cytoskeletal Defects

Red Blood Cell Membrane Fluctuations and Shape Controlled by ATP-Induced Cytoskeletal Defects

Biconcave shape of human red-blood-cell ghosts relies on density differences between the rim and dimple of the ghost's plasma membrane

Erythrocyte Shape Change Prevents Plasmodium falciparum Invasion

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