scholarly journals Human and mouse hemoglobin association with the transgenic mouse erythrocyte membrane

FEBS Letters ◽  
2006 ◽  
Vol 580 (18) ◽  
pp. 4485-4490 ◽  
Author(s):  
Qiuying Chen ◽  
Tania C. Balazs ◽  
Ronald L. Nagel ◽  
Rhoda Elison Hirsch
Keyword(s):  
Transgenic Mouse ◽  
Erythrocyte Membrane ◽  
Mouse Erythrocyte ◽  
Human And Mouse

scholarly journals Two non-vesicular ATP release pathways in the mouse erythrocyte membrane

FEBS Letters ◽  
2011 ◽  
Vol 585 (21) ◽  
pp. 3430-3435 ◽  
Author(s):  
Feng Qiu ◽  
Junjie Wang ◽  
David C. Spray ◽  
Eliana Scemes ◽  
Gerhard Dahl
Keyword(s):  
Erythrocyte Membrane ◽  
Atp Release ◽  
Mouse Erythrocyte

scholarly journals An antigen of Plasmodium yoelii that translocates into the mouse erythrocyte membrane upon entry into the host cell

1985 ◽  
Vol 73 (1) ◽  
pp. 311-320
Author(s):  
K. Murakami ◽  
K. Tanabe
Keyword(s):  
Host Cell ◽  
Erythrocyte Membrane ◽  
Plasmodium Yoelii ◽  
Erythrocyte Membranes ◽  
Rodent Malaria Parasite ◽  
Strong Fluorescence ◽  
Cytoplasmic Surface ◽  
Parasite Plasmodium ◽  
Mouse Erythrocyte

Monoclonal antibodies against the rodent malaria parasite, Plasmodium yoelii, have been prepared and characterized by indirect immunofluorescence on acetone-fixed infected mouse erythrocytes. The antibody of clone K2 reacted strongly with late trophozoites and schizonts, whereas it did so weakly and diffusely with ring forms and early trophozoites. Strong fluorescence was confined to granular structures in schizonts and merozoites. Parasites that invaded erythrocytes in vitro lost the strong fluorescence. Instead, immunofluorescence appeared in the membranes of erythrocytes infected in vitro with merozoites. Erythrocytes infected with more than one merozoite had intensified immunofluorescence in their membranes. Staining of the invaded erythrocytes with 4′,6-diamidino-2-phenylindole (DAPI) hydrochloride demonstrated that membranes of all the invaded erythrocytes acquired the P. yoelii antigen. These results suggest that the P. yoelii antigen in merozoites is translocated into erythrocyte membranes upon entry into the host cell. Immunofluorescence continued to appear in membranes of infected erythrocytes throughout the intra-erythrocytic parasite growth. Staining of unfixed infected erythrocytes with the K2 antibody failed to detect the parasite antigen. In contrast, immunofluorescence was present in unfixed membranes of erythrocyte ghosts, which had been spontaneously formed after rupture of schizont-infected erythrocytes by merozoite release. No immunofluorescence appeared in either acetone-fixed or unfixed ghosts of normal erythrocytes. These results suggest the antigenic determinant of the P. yoelii antigen is exposed at the cytoplasmic surface of the infected erythrocyte membrane. Immunoprecipitation has revealed that the K2 antibody recognizes a 160 X 10(3) Mr P. yoelii antigen.

scholarly journals iPLA2β Contributes to Activation of Human and Mouse Platelets Via ITAM Receptors Fcγ RIIA and GPVI

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2339-2339
Author(s):  
Shaji Abraham ◽  
Pravin Patel ◽  
Ulhas P. Naik ◽  
Steven Edward McKenzie
Keyword(s):  
Transgenic Mouse ◽  
Platelet Activation ◽  
Conflicts Of Interest ◽  
Human Platelets ◽  
Significant Inhibition ◽  
Dense Granule ◽  
Secretory Cells ◽  
Western Blots ◽  
Granule Secretion ◽  
Human And Mouse

Platelet activation by ITAM receptors contributes to hemostasis, thrombosis, vascular integrity and host defense. In the course of our studies of FcγRIIA-mediated platelet activation, we became interested in those mechanisms that require neither full Syk activation nor changes in intracellular calcium. Calcium-independent phospholipase family member iPLA2β has been observed to modulate phospholipid remodeling and second messenger generation in human platelets (Beckett, Thromb Res 2007; Duvernay, Biochem 2015), while iPLA2γ has been studied in knockout mouse platelets (Yoda, JTH 2014) with modest effects noted on thrombosis and hemostasis. These enzymes do not require increased cytoplasmic calcium for their activity in cleaving the acyl group from the sn2 position of phospholipids to yield a free fatty acid and a lysophospholipid. However, the precise role of iPLA2β in human and mouse platelet activation has not been elucidated. Neither has the contribution of iPLA2β in the response to FcγRIIA-mediated activation been reported. We identified the presence of iPLA2β protein in western blots of human and FcγRIIA transgenic mouse platelets. Of interest, multiple isoforms arising from proteolytic cleavage were detected. We treated washed human and FcγRIIA transgenic mouse platelets with agonists to FcγRIIA (IV.3 + GAM) and to GPVI (collagen or collagen-related peptide) in the absence and presence of pharmacologic inhibitors of iPLA2β. At a range of agonist doses up to 3X threshold, we observed significant inhibition of aggregation, dense granule secretion and alpha granule secretion (p<0.05 vs. vehicle only, n = 3 to 4 each). Inhibition occurred with either S-BEL (bromo-enolactone) or with FKGK18 (a fluoroketone), two chemically distinct iPLA2β inhibitor molecules with different modes of action. The IC50 for S-BEL was found to be 1.02 uM for human FcγRIIA, 2.04 uM for human GPVI, and 2.76 uM for transgenic mouse FcγRIIA activated platelets. FKGK18 was less potent, with IC50s at 7.88 uM for human FcγRIIA. In contrast, iPLA2γ inhibitor R-BEL was able to inhibit FcγRIIA -mediated activation, but at an IC50 of 2.62 uM. Notably, iPLA2β inhibition could eliminate ATP secretion from dense granules downstream of FcγRIIA and GPVI activation. When we added ADP to FcγRIIA stimulation in the presence of inhibitory doses of S-BEL, we overcame the inhibition. We have identified for the first time that iPLA2β contributes to aggregation and secretion of both human and FcγRIIA transgenic mouse platelets. The platelets were slightly more sensitive to FcγRIIA than to GPVI inhibition. In other activatable secretory cells, iPLA2β plays both a homeostatic and signaling role. The mechanisms of iPLA2β action in platelets merit further study. Studies are in progress with genetic knockdown and knockout of the enzyme, to complement the findings with inhibitors. Disclosures No relevant conflicts of interest to declare.

Influence of Aerobic Oxidation of Mouse Erythrocytes on their Recognition by Macrophages

2000 ◽  
Vol 20 (3) ◽  
pp. 157-166
Author(s):  
Gemma Olmos ◽  
L. Alfredo Lotero ◽  
Angel Herráez ◽  
F. Javier Alvarez ◽  
Juan C. Murciano ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Cell Surface ◽  
Erythrocyte Membrane ◽  
Gel Electrophoresis ◽  
Phosphate Buffer ◽  
Protein Modification ◽  
Aerobic Oxidation ◽  
Cell Surface Properties ◽  
Mouse Erythrocyte ◽  
Membrane Changes

Membrane protein modification can change cell surface properties which canbe correlated with altered macrophage-erythrocyte interactions. Mouseerythrocytes were incubated in phosphate buffer for different times toinduce protein modification. Mouse erythrocyte membrane changes wereanalyzed by infrared analyses and gel electrophoresis. Proteolyticdigestion of membrane proteins was observed. After 22 hours preliminaryincubation, the number of erythrocytes adhering to a monolayer ofmacrophages reached a maximum, the majority of which had not beenphagocytosed. Most of the erythrocytes incubated for 40 hours underwentphagocytosis after adhesion to the macrophages.

Observation of Concanavalin-A receptors on hydrated planar erythrocyte membrane film by in situ electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 608-609
Author(s):  
Neng-Bo He ◽  
S.W. Hui
Keyword(s):  
Lipid Bilayers ◽  
Erythrocyte Membrane ◽  
Lipid Membranes ◽  
Surface Film ◽  
Biological Membranes ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Black Lipid Membranes ◽  
Fine Mesh ◽  
Planar Films

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).

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