scholarly journals Reduction in flippase activity contributes to surface presentation of phosphatidylserine in human senescent erythrocytes

2020 ◽  
Vol 24 (23) ◽  
pp. 13991-14000
Author(s):  
Momoko Seki ◽  
Nobuto Arashiki ◽  
Yuichi Takakuwa ◽  
Kosaku Nitta ◽  
Fumio Nakamura
Keyword(s):  
Senescent Erythrocytes

scholarly journals Hemolysis in the spleen drives erythrocyte turnover

Blood ◽  
2020 ◽  
Author(s):  
Thomas robert leon Klei ◽  
Jill Jasmine Dalimot ◽  
Benjamin Nota ◽  
Martijn Veldthuis ◽  
Erik Mul ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Matrix Proteins ◽  
Human Spleen ◽  
Erythrocyte Adhesion ◽  
Subsequent Degradation ◽  
Macrophage Subpopulations ◽  
Senescent Erythrocytes ◽  
Red Pulp

Red pulp macrophages of the spleen mediate turnover of billions of senescent erythrocytes per day. However, the molecular mechanisms involved in sequestration of senescent erythrocytes, their recognition and their subsequent degradation by red pulp macrophages remain unclear. In this study we provide evidence that the splenic environment is of substantial importance in facilitating erythrocyte turnover through induction of hemolysis. Upon isolating human spleen red pulp macrophages we noted a substantial lack of macrophages that were in the process of phagocytosing intact erythrocytes. Detailed characterization of erythrocyte and macrophage subpopulations from human spleen tissue led to the identification of erythrocytes that are devoid of hemoglobin, so-called erythrocyte ghosts. By in vivo imaging and transfusion experiments we further confirmed that senescent erythrocytes that are retained in the spleen are subject to hemolysis. Additionally, we show that erythrocyte adhesion molecules, which are specifically activated on aged erythrocytes, cause senescent erythrocytes to interact with extracellular matrix proteins that are exposed within the splenic architecture. Such adhesion molecule-driven retention of senescent erythrocytes, under low shear conditions, was found to result in steady shrinkage of the cell and ultimately resulted in hemolysis. In contrast to intact senescent erythrocytes, the remnant erythrocyte ghost shells were prone to recognition and breakdown by red pulp macrophages. These data identify hemolysis as a key event in the turnover of senescent erythrocytes, which alters our current understanding of how erythrocyte degradation is regulated.

Molecular mechanisms of erythrophagocytosis. Characterization of the senescent erythrocytes that are phagocytized by macrophages

1997 ◽  
Vol 320 (10) ◽  
pp. 811-818 ◽  
Author(s):  
Daniela Bratosin ◽  
Joël Mazurier ◽  
Jean-Pierre Tissier ◽  
Christian Slomianny ◽  
Jérôme Estaquier ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Senescent Erythrocytes

scholarly journals Hepcidin and iron regulation, 10 years later

Blood ◽  
2011 ◽  
Vol 117 (17) ◽  
pp. 4425-4433 ◽  
Author(s):  
Tomas Ganz
Keyword(s):  
Iron Overload ◽  
Host Defense ◽  
Iron Regulation ◽  
Iron Availability ◽  
Iron Transfer ◽  
Hemoglobin Synthesis ◽  
Metabolic Functions ◽  
Iron Supply ◽  
Infection And Inflammation ◽  
Senescent Erythrocytes

Abstract Under evolutionary pressure to counter the toxicity of iron and to maintain adequate iron supply for hemoglobin synthesis and essential metabolic functions, humans and other vertebrates have effective mechanisms to conserve iron and to regulate its concentration, storage, and distribution in tissues. The iron-regulatory hormone hepcidin, first described 10 years ago, and its receptor and iron channel ferroportin control the dietary absorption, storage, and tissue distribution of iron. Hepcidin causes ferroportin internalization and degradation, thereby decreasing iron transfer into blood plasma from the duodenum, from macrophages involved in recycling senescent erythrocytes, and from iron-storing hepatocytes. Hepcidin is feedback regulated by iron concentrations in plasma and the liver and by erythropoietic demand for iron. Genetic malfunctions affecting the hepcidin-ferroportin axis are a main cause of iron overload disorders but can also cause iron-restricted anemias. Modulation of hepcidin and ferroportin expression during infection and inflammation couples iron metabolism to host defense and decreases iron availability to invading pathogens. This response also restricts the iron supply to erythropoietic precursors and may cause or contribute to the anemia associated with infections and inflammatory disorders.

scholarly journals Mechanisms of adenosine 5'-monophosphate catabolism in human erythrocytes

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 988-992 ◽  
Author(s):  
DE Paglia ◽  
WN Valentine ◽  
M Nakatani ◽  
RA Brockway
Keyword(s):  
Potential Role ◽  
Adenine Nucleotide ◽  
Acidic Ph ◽  
Amp Deaminase ◽  
Severe Deficiency ◽  
Erythrocyte Enzyme ◽  
Senescent Erythrocytes ◽  
Adenine Nucleotide Pool ◽  
Normal Controls

Abstract Uncertainties regarding the role of pyrimidine nucleotidase (PyrNase) in AMP catabolism were resolved by studies of erythrocytes from normal controls, controls with young mean cell ages, and patients with hereditary hemolytic anemia due to severe deficiency of PyrNase. Hemolysates from the latter exhibited undiminished capacity to dephosphorylate AMP over a broad range of pH, indicating that PyrNase was not directly involved. In each subject group, the rates of AMP dephosphorylation between pH 5.1 and 8.3 were indistinguishable from those of IMP, suggesting a potential role for AMP-deaminase, an erythrocyte enzyme that was stimulated by coformycin at pH 7.2. Quantitative analysis of catabolites in incubated hemolysates confirmed that AMP degradation preferentially occurred via deamination to IMP with subsequent dephosphorylation by another erythrocyte nucleotidase isozyme, deoxyribonucleotidase. Both AMP-deaminase and deoxyribonucleotidase have acidic pH optima with minimal activities at physiologic pH, suggesting that this pathway of AMP catabolism could accelerate depletion of the adenine nucleotide pool and thereby mediate the demise of senescent erythrocytes sequestered in the spleen.

Senescent Erythrocytes Exhibit a Single-Hit Response to Staphylococcal Alpha Toxin

Gerontology ◽  
1997 ◽  
Vol 44 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Lana Kantor ◽  
Hugh B. Fackrell
Keyword(s):  
Alpha Toxin ◽  
Senescent Erythrocytes

Study of phagocytosis of senescent erythrocytes in young and elderly individuals

2003 ◽  
Vol 2 (4) ◽  
pp. 197-198 ◽  
Author(s):  
C. Biondi ◽  
C. Cotorruelo ◽  
S. Garcia Borr�s ◽  
L. Rocca ◽  
A. Ensinck ◽  
...  
Keyword(s):  
Elderly Individuals ◽  
Senescent Erythrocytes

Effects of Aging on Antioxidant Response and Phagocytosis in Senescent Erythrocytes

2009 ◽  
Vol 38 (6) ◽  
pp. 551-559 ◽  
Author(s):  
Melina Luján Brajovich ◽  
Angel Rucci ◽  
Irma L. Acosta ◽  
Carlos Cotorruelo ◽  
Silvia García Borrás ◽  
...  
Keyword(s):  
Antioxidant Response ◽  
Senescent Erythrocytes ◽  
Effects Of Aging
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