Studies on the effect of vanadate on endocytosis and shape changes in human red blood cells and ghosts

Schrier, Stanley L.; Junga, Irene; Ma, Lisa

doi:10.1182/blood.v68.5.1008.1008

Cited by 32 publications

(12 citation statements)

References 33 publications

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“…By comparison, the neutrophil plasma membrane did not require additional methods to remove cytoskeletal proteins to become fusogenic. Spectrin has been shown to inhibit Ca2÷-dependent fusion of liposomes [50,51] and its deficiency in red cells is associated with membrane deformations due to fusions [52]. Our results are consistent with these reports, but we have extended these observations to show that treatment resulting in spectrin depletion was associated with an increased potential of the inner leaflet of red plasma membranes to fuse in a Ca2+-dependent manner.…”

Section: Discussionsupporting

confidence: 91%

Calcium-dependent fusion of the plasma membrane fraction from human neutrophils with liposomes

Francis

Smolen

Balazovich

et al. 1990

Biochimica et Biophysica Acta (BBA) - Biomembranes

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A cell-free assay monitoring lipid mixing was used to investigate the role of Ca2+ in neutrophil membrane-liposome fusion. Micromolar concentrations of Ca2+ were found to directly stimulate fusion of inside-out neutrophil plasma membrane enriched fractions (from neutrophils subjected to nitrogen cavitation) with liposomes (phosphatidylethanolamine:phosphatidic acid, 4:1 molar ratio). In contrast, right-side-out plasma membranes and granule membranes did not fuse with liposomes in the presence of Ca2+. Similar results were obtained with two different lipid mixing assays. Fusion of the neutrophil plasma membrane-enriched fraction with liposomes was dependent upon the concentration of Ca2+, with threshold and 50% maximal rate of fusion occurring at 2 microM and 50 microM, respectively. Furthermore, the fusion was highly specific for Ca2+; other divalent cations such as Ba2+, Mg2+ and Sr2+ promoted fusion only at millimolar concentrations. Red blood cell (RBC) membranes were used in control studies. Ca2(+)-dependent fusion did not occur between right-side-out or inside-out RBC-vesicles and liposomes. However, if the RBC-vesicles were exposed to conditions which depleted spectrin (i.e., low salt), then Ca2(+)-dependent fusion was detected. Other quantitative differences between neutrophil and RBC membranes were found; fusion of liposomes with RBC membranes was most readily achieved with La3+ while neutrophil membrane-liposome fusion was most readily obtained with Ca2+. Furthermore, GTP gamma S was found to enhance Ca2(+)-dependent fusion between liposomes and neutrophil plasma membranes, but not RBC membranes. These studies show that plasma membranes (enriched fractions) from neutrophils are readily capable of fusing with artificial lipid membranes in the presence of micromolar concentrations of Ca2+.

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Section: Discussionsupporting

confidence: 91%

Calcium-dependent fusion of the plasma membrane fraction from human neutrophils with liposomes

Francis

Smolen

Balazovich

et al. 1990

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…Endocytosis can be increased by certain conditions or the presence of certain factors, such as hypotonicity, EDTA, trypsin, and an energy source (Schrier et al, 1986). Erythrocyte energetics and calcium ions provide an opportunity for membrane invagination and fusion with formation of endocytotic vacuoles (Schrier et al, 1978).…”

Section: Resultsmentioning

confidence: 99%

Biochemically altered human erythrocytes as a carrier for targeted delivery of primaquine: an In Vitro study

et al. 2011

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The aim of this study was to investigate human erythrocytes as a carrier for targeted drug delivery of primaquine (PQ). The process of PQ loading in human erythrocytes, as well as the effect of PQ loading on the oxidative status of erythrocytes, was also studied. At PQ concentrations of 2, 4, 6, and 8 mg/mL and an incubation time of 2 h, the ratios of the concentrations of PQ entrapped in erythrocytes to that in the incubation medium were 0.515, 0.688, 0.697 and 0.788, respectively. The maximal decline of erythrocyte reduced glutathione content was observed at 8 mg/mL of PQ compared with native erythrocytes p < 0.001. In contrast, malondialdehyde and protein carbonyl were significantly increased in cells loaded with PQ (p < 0.001). Furthermore, osmotic fragility of PQ carrier erythrocytes was increased in comparison with unloaded cells. Electron microscopy revealed spherocyte formation with PQ carrier erythrocytes. PQ-loaded cells showed sustained drug release over a 48 h period. Erythrocytes were loaded with PQ successfully, but there were some biochemical as well as physiological changes that resulted from the effect of PQ on the oxidative status of drug-loaded erythrocytes. These changes may result in favorable targeting of PQ-loaded cells to reticulo-endothelial organs. The relative impact of these changes remains to be explored in ongoing animal studies.

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“…Therefore, NaF inhibits drug-induced endocytosis by inhibiting the glycolytic synthesis of ATP [ 18,191. Drug-induced endocytosis is also specifically blocked by vanadate [20]. However, spontaneous endocytosis was not preceded by stomatocytic shape change and is not blocked by preincubation with NaF or vanadate.…”

Section: Discussionmentioning

confidence: 89%

Spontaneous endocytosis in human neonatal and adult red blood cells: Comparison to drug‐induced endocytosis and to receptor‐mediated endocytosis

Colin

Schrier

1991

American J Hematol

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Neonatal RBC contain many more spontaneous endocytic vacuoles than do adult RBC. It is not known if this difference is a result of an increase in production of vacuoles in the neonatal RBC (as is the case in drug-induced endocytosis), or is the result of a less effective neonatal macrophagic "pitting" process. Using an in vitro model of spontaneous endocytosis, we compared the rate and quantity of vacuoles and the shape of cord and adult RBC containing pits, visible by interference contrast microscopy (Nomarski method). The mechanism of the spontaneous endocytosis was explored using different inhibitors: sodium vanadate an inhibitor of ATPases, sodium fluoride which inhibits the generation of ATP and sodium cyanide a potent inhibitor of oxidative phosphorylation. We then compared spontaneous endocytosis with two other forms of RBC endocytosis: drug-induced endocytosis and receptor-mediated endocytosis. Spontaneous endocytosis is in fact increased in neonatal RBC initially but the increase in number of RBC containing pits after 144 hr of incubation is almost the same in adult RBC and neonatal RBC. Comparing spontaneous endocytosis with drug-induced endocytosis, it appears that their mechanisms are different in that spontaneous endocytosis is not preceded by stomatocytic shape change and is not inhibited by sodium vanadate or sodium fluoride as is the case for drug-induced endocytosis. Spontaneous endocytosis is different than transferrin receptor-mediated endocytosis because it occurs in many RBC, not only in the motile R1 reticulocytes and is not inhibited by sodium cyanide as is receptor-mediated endocytosis. Thus spontaneous endocytosis appears to be different than drug-induced endocytosis and transferrin receptor-mediated endocytosis. The increase in spontaneous endocytosis in cord RBC seen in vivo is probably a consequence of an immaturity of the neonatal macrophage pitting process.

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Studies on the effect of vanadate on endocytosis and shape changes in human red blood cells and ghosts

Cited by 32 publications

References 33 publications

Calcium-dependent fusion of the plasma membrane fraction from human neutrophils with liposomes

Calcium-dependent fusion of the plasma membrane fraction from human neutrophils with liposomes

Biochemically altered human erythrocytes as a carrier for targeted delivery of primaquine: an In Vitro study

Spontaneous endocytosis in human neonatal and adult red blood cells: Comparison to drug‐induced endocytosis and to receptor‐mediated endocytosis

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