scholarly journals Red blood cells protect oxygen transport with adrenergic sodium-proton exchangers in hypoxic and hypercapnic white seabass

2021 ◽  
Author(s):  
Till S. Harter ◽  
Alexander M. Clifford ◽  
Martin Tresguerres

AbstractWhite seabass (Atractoscion nobilis) are increasingly experiencing periods of low oxygen (O2; hypoxia) and high carbon dioxide (CO2, hypercapnia) due to climate change and eutrophication of the coastal waters of California. Haemoglobin (Hb) is the principal O2 carrier in the blood and in many teleost fishes Hb-O2 binding is compromised at low pH. However, Hb is contained within red blood cells (RBC) that, in some species, regulate intracellular pH with adrenergically-stimulated sodium-proton-exchangers (β-NHE). We hypothesised that white seabass have RBC β-NHEs that protect the blood O2-carrying capacity during hypoxia and hypercapnia. In a series of in vitro experiments, we determined the O2-binding characteristics of white seabass blood, the response of RBCs to adrenergic stimulation, and quantified the protective effect of β-NHE activity on Hb-O2 saturation during a hypercapnic acidosis in normoxia and hypoxia. White seabass had typical teleost Hb characteristics, with a moderate O2 affinity that was highly pH-sensitive. Functional, molecular and bioinformatic data confirmed that white seabass have RBC β-NHEs, and super-resolution imaging revealed, for the first time, the subcellular location of β-NHE protein in intracellular vesicles and on the RBC membrane. The activation of RBC β-NHEs increased Hb-O2 saturation by ∼8% in normoxia at 1% PCO2, and by ∼20% in hypoxia at arterial PCO2 (0.3%), but the protective effects decreased at higher PCO2. Combined, these data indicate that RBC β-NHE activity in white seabass can safeguard arterial O2 transport and the mechanism likely plays an important role in the fishes’ physiological response to environmental hypoxia and hypercapnia.Summary StatementWhite seabass have highly pH-sensitive haemoglobins, but their red blood cells can actively protect oxygen transport during hypoxia and hypercapnia, conditions that occur more frequently due to a changing climate.

1979 ◽  
Vol 236 (3) ◽  
pp. R221-R224 ◽  
Author(s):  
H. Bartels ◽  
R. Bartels ◽  
R. Baumann ◽  
R. Fons ◽  
K. D. Jurgens ◽  
...  

Blood parameters concerning oxygen transport and relative organ weights of 11 Suncus etruscus and 13 Crocidura russula under light halothane anesthesia were investigated. Mean body weight of S. etruscus was 2.5 g and for C. russula was 9 g, hemoglobin concentration was 17.4 and 15.6 g/100 ml blood, hematocrit was 50 and 44%, red blood cells were 18 and 11 X 10(6)/microliter, respectively. Mean corpuscular volume was calculated to be 26 and 41 micron3, mean diameter 5.5 and 7 micron, and mean thickness 1.2 and 1.1 micron, respectively. Mean corpuscular hemoglobin concentration was in the normal range of mammalian red blood cells. A blood oxygen half-saturation pressure of 35 and 34 Torr at pH 7.4, 37 degrees C and a Bohr factor deltalog P50/deltapH of -0.61 and -0.66 was measured. Experiments with stripped hemoglobin showed that 2,3-diphosphoglycerate is the main oxygen affinity reducing allosteric factor. Relative weights of heart, kidney, and liver are remarkably high in S. etruscus. The maximal oxygen transport of 400 ml . kg-1 . min-1 of S. etruscus is feasible by an enormous heart rate, a large relative stroke volume, a high hemoglobin concentration combined with a low oxygen affinity, and a large Bohr effect.


2018 ◽  
Vol 1 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Sudeshna Paul ◽  
Shamreen Naaz ◽  
Arnab Kumar Ghosh ◽  
Sanatan Mishra ◽  
Aindrila Chattopadhyay ◽  
...  

Oxidative stress is an important causative factor for a number of diseases. Phenylhydrazine (PHZ) is a widely accepted model for studying hemolytic anemia by induction of oxidative stress. In the present study, goat red blood cells (RBCs) were incubated in vitro with PHZ (1mM) to generate oxidative stress. To test whether melatonin exhibits protective effects on PHZ induced RBC damage and to explore its potential molecular mechanisms, different concentrations of melatonin (5, 10, 20 and 40 nmoles/ml) were also included. PHZ caused altered profiles on biomarkers of oxidative stress and antioxidative as well as glucose metabolic enzymes in RBCs. These alterations indicated a development of oxidative stress. Melatonin at a concentration of 40 nmoles/ml provided optimal protection against all alterations induced by PHZ. The important cellular membrane proteins, including spectrin and actin, were also damaged by PHZ and this led to RBC deformation similar to that of observed in severe β-thalassaemia; the RBC deformation was also prevented by melatonin. Binding profiles of melatonin with PHZ and ferrous iron indicated favorable binding of melatonin with both of them, respectively. Thus, in addition to the direct antioxidant and free radical scavenging capability, melatonin also inhibited iron overloading by chelating iron and binding with the PHZ. This action of melatonin further reduces free radical generation. Based on the results, melatonin may provide therapeutic relevance to ß-thalassemia and other hemolytic RBC disorders involving oxidative stress. 


2021 ◽  
Author(s):  
Takeshi Ono ◽  
Yoko Yamaguchi ◽  
Hiroyuki Nakashima ◽  
Masahiro Nakashima ◽  
Takuya Ishikiriyama ◽  
...  

Malaria remains a grave concern for humans, as effective medical countermeasures for Plasmodium infection have yet to be developed. Phagocytic clearance of parasitized red blood cells (pRBCs) by macrophages is an important front-line innate host defense against Plasmodium infection. We previously showed that repeated injections of low-dose lipopolysaccharide (LPS) prior to bacterial infection, called LPS preconditioning, strongly augmented phagocytic/bactericidal activity in murine macrophages. However, if LPS preconditioning prevents murine Plasmodium infection is unclear. We investigated the protective effects of LPS preconditioning against lethal murine Plasmodium infection, focusing on CD11b high F4/80 low liver macrophages, which are increased by LPS preconditioning. Mice were subjected to LPS preconditioning by intraperitoneal injections of low-dose LPS for 3 consecutive days, and 24 h later, they were intravenously infected with pRBCs of Plasmodium yoelii 17XL. LPS preconditioning markedly increased the murine survival and reduced parasitemia, while it did not reduce TNF secretions, only delaying the peak of plasma IFN-γ after Plasmodium infection in mice. An in vitro phagocytic clearance assay of pRBCs showed that the CD11b high F4/80 low liver macrophages, but not spleen macrophages, in the LPS-preconditioned mice had significantly augmented phagocytic activity against pRBCs. The adoptive transfer of CD11b high F4/80 low liver macrophages from LPS-preconditioned mice to control mice significantly improved the survival after Plasmodium infection. We conclude that LPS preconditioning stimulated CD11b high F4/80 low liver macrophages to augment the phagocytic clearance of pRBCs, which may play a central role in resistance against Plasmodium infection.


2020 ◽  
Author(s):  
Takeshi Ono ◽  
Yoko Yamaguchi ◽  
Hiroyuki Nakashima ◽  
Masahiro Nakashima ◽  
Takuya Ishikiriyama ◽  
...  

AbstractMalaria remains a grave concern for humans, as effective medical countermeasures for malaria infection have yet to be developed. Phagocytic clearance of parasitized red blood cells (pRBCs) by macrophages is an important front-line innate host defense against malaria infection. We previously showed that repeated injections of low-dose lipopolysaccharide (LPS) prior to bacterial infection, called LPS preconditioning, strongly augmented phagocytic/bactericidal activity in murine macrophages. However, how LPS preconditioning prevents murine malaria infection is unclear. We investigated the protective effects of LPS preconditioning against lethal murine malaria infection, focusing on CD11bhigh F4/80low liver macrophages, which are increased by LPS preconditioning. Mice were subjected to LPS preconditioning by intraperitoneal injections of low-dose LPS for 3 consecutive days, and 24 h later, they were intravenously infected with pRBCs of Plasmodium yoelii 17XL. LPS preconditioning markedly increased the murine survival and reduced parasitemia, while it did not reduce TNF secretions, only delaying the peak of plasma IFN-γ after malaria infection in mice. An in vitro phagocytic clearance assay of pRBCs showed that the CD11bhigh F4/80low liver macrophages of the LPS-preconditioned mice had significantly augmented phagocytic activity against pRBCs. The adoptive transfer of CD11bhigh F4/80low liver macrophages from LPS-preconditioned mice to control mice significantly improved the survival after malaria infection. We conclude that LPS preconditioning stimulated CD11bhigh F4/80low liver macrophages to augment the phagocytic clearance of pRBCs, which may play a central role in resistance against malaria infection. LPS preconditioning may be an effective tool for preventing malaria infection.


Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).


2013 ◽  
Vol 1 (Suppl. 1) ◽  
pp. A4.1
Author(s):  
Angela Storka
Keyword(s):  

1950 ◽  
Vol 183 (2) ◽  
pp. 757-765 ◽  
Author(s):  
David Shemin ◽  
Irving M. London ◽  
D. Rittenberg
Keyword(s):  

2021 ◽  
pp. 153537022110132
Author(s):  
Shu-Qin Liu ◽  
Xiao-Ye Hou ◽  
Feng Zhao ◽  
Xiao-Ge Zhao

Heart regeneration is negligible in humans and mammals but remarkable in some ectotherms. Humans and mammals lack nucleated red blood cells (NRBCs), while ectotherms have sufficient NRBCs. This study used Bufo gargarizan gargarizan, a Chinese toad subspecies, as a model animal to verify our hypothesis that NRBCs participate in myocardial regeneration. NRBC infiltration into myocardium was seen in the healthy toad hearts. Heart needle-injury was used as an enlarged model of physiological cardiomyocyte loss. It recovered quickly and scarlessly. NRBC infiltration increased during the recovery. Transwell assay was done to in vitro explore effects of myocardial injury on NRBCs. In the transwell system, NRBCs could infiltrate into cardiac pieces and could transdifferentiate toward cardiomyocytes. Heart apex cautery caused approximately 5% of the ventricle to be injured to varying degrees. In the mildly to moderately injured regions, NRBC infiltration increased and myocardial regeneration started soon after the inflammatory response; the severely damaged region underwent inflammation, scarring, and vascularity before NRBC infiltration and myocardial regeneration, and recovered scarlessly in four months. NRBCs were seen in the newly formed myocardium. Enzyme-linked immunosorbent assay and Western blotting showed that the levels of tumor necrosis factor-α, interleukin- 1β, 6, and11, cardiotrophin-1, vascular endothelial growth factor, erythropoietin, matrix metalloproteinase- 2 and 9 in the serum and/or cardiac tissues fluctuated in different patterns during the cardiac injury-regeneration. Cardiotrophin-1 could induce toad NRBC transdifferentiation toward cardiomyocytes in vitro. Taken together, the results suggest that the NRBC is a cell source for cardiomyocyte renewal/regeneration in the toad; cardiomyocyte loss triggers a series of biological processes, facilitating NRBC infiltration and transition to cardiomyocytes. This finding may guide a new direction for improving human myocardial regeneration.


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