Mechanisms of perturbation of erythrocyte calcium homeostasis in favism

Damonte, Gianluca; Guida, Lucrezia; Sdraffa, Adina; Benatti, Umberto; Melloni, Edon; Fórteleoni, G; Meloni, T; Carafoli, Ernesto; Flora, Antonio De

doi:10.1016/0143-4160(92)90075-4

Cited by 36 publications

(25 citation statements)

References 28 publications

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“…1 This may be important for erythrocyte ageing, which is paralleled by increase of cytosolic Ca 2+ activity. 21,22 Moreover, according to the present results, oxidative stress or defects of antioxidative defence 23 clearly enhance Ca 2+ entry via the cation channels. This leads to higher intracellular Ca 2+ concentrations and thus accelerates erythrocyte apoptosis and clearance.…”

Section: Discussionmentioning

confidence: 96%

Cation channels trigger apoptotic death of erythrocytes

et al. 2003

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Erythrocytes are devoid of mitochondria and nuclei and were considered unable to undergo apoptosis. As shown recently, however, the Ca 2+ -ionophore ionomycin triggers breakdown of phosphatidylserine asymmetry (leading to annexin binding), membrane blebbing and shrinkage of erythrocytes, features typical for apoptosis in nucleated cells. In the present study, the effects of osmotic shrinkage and oxidative stress, well-known triggers of apoptosis in nucleated cells, were studied. Exposure to 850 mOsm for 24 h, to tert-butylhydroperoxide (1 mM) for 15 min, or to glucose-free medium for 48 h, all elicit erythrocyte shrinkage and annexin binding, both sequelae being blunted by removal of extracellular Ca 2+ and mimicked by ionomycin (1 lM). Osmotic shrinkage and oxidative stress activate Ca 2+ -permeable cation channels and increase cytosolic Ca 2+ concentration. The channels are inhibited by amiloride (1 mM), which further blunts annexin binding following osmotic shock, oxidative stress and glucose depletion. In conclusion, osmotic and oxidative stress open Ca 2+ -permeable cation channels in erythrocytes, thus increasing cytosolic Ca 2+ activity and triggering erythrocyte apoptosis.

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Section: Discussionmentioning

confidence: 96%

Cation channels trigger apoptotic death of erythrocytes

et al. 2003

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“…In monocytes treated with interleukin-4, large amounts of 15-LOa are expressed in the cytosol and the intracellular activity of the enzyme with endogenous substrates is limited [44]. In contrast, in mature reticulocytes the intracellular calcium concentration is in the micromolar range [45,46] and a significant proportion of the enzyme is membrane bound, leading to the detection of specific lipoxygenase products in the membrane lipids [16]. We have demonstrated that 15-LOb1 associates with the membranes of lysates from human PrEC cells and the membrane fraction from calcium ionophore-treated intact PrEC cells in a Ca 2+ -dependent manner.…”

Section: Discussionmentioning

confidence: 99%

Differential characteristics of human 15‐lipoxygenase isozymes and a novel splice variant of 15S‐lipoxygenase

Kilty

Logan

Vickers

1999

European Journal of Biochemistry

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The lipoxygenases (LOs) are a family of nonheme iron dioxygenases that catalyse the insertion of molecular oxygen into polyunsaturated fatty acids. Five members of this gene family have been described in man, 5-LO, 12S-LO, 12R-LO, 15-LO and 15S-LO. Using partially purified recombinant 15S-LO enzyme and cells constitutively expressing this protein, we have compared the activity, substrate specificity, kinetic characteristics and regulation of this enzyme to that previously reported for 15-LO. 15S-LO has a threefold higher K m , similar V max and increased specificity of oxygenation for arachidonic acid, and a similar K m but decreased V max for linoleic acid in comparison to 15-LO. Unlike 15-LO, 15S-LO is not suicide inactivated by the products of fatty acid oxygenation. However, in common with other LOs, 15S-LO activity is regulated through calcium-dependent association of the enzyme with the membrane fraction of cells.In addition, whilst independently cloning the recently described 15S-LO, we identified a splice variant containing an in-frame 87-bp deletion corresponding to amino acids 401±429 inclusive. Modelling of the 15S-LO and subsequent studies with partially purified recombinant protein suggest that the deleted region comprises a complete a-helix flanking the active site of the enzyme resulting in decreased specificity of oxygenation and affinity for fatty acid substrates.Alternative splicing of 15S-LO would therefore provide a further level of regulation of fatty acid metabolism. These results demonstrate that there are substantial differences in the enzyme characteristics and regulation of the 15-LO isozymes which may reflect differing roles for the proteins in vivo. Although the LOs produce specific hydroxyeicosatetraenoic (HETE) enantiomers, the enzymes do not all display absolute positional specificity with respect to oxygenation of AA. For example, while 15-LOb exclusively oxygenates C15 of AA [8], 15-LOa oxygenates AA at both C15 and C12 [9]. In addition, the degree of homology between members of the LO family does not define the product profile. For example, amino acid sequence alignments demonstrate that 15-LOb is more closely related to 12R-LO than 15-LOa, suggesting complex evolutionary paths in the LO family.The LOs are responsible for the synthesis of a number of inflammatory mediators, including leukotrienes and lipoxins, which are implicated in inflammatory disorders such as bronchial asthma [10]. Lipoxygenase metabolites have also been implicated in a number of noninflammatory biological processes. For example, 12-HETE and 15-HETE have been implicated in tumour metastases and the formation of atherosclerotic plaques, respectively [11,12]. The important biological roles of these LO metabolites and the complexity of substrate utilization by members of the LO family emphasize the importance of understanding factors which affect the activity and regulation of these enzymes.Overexpression and characterization of recombinant 5-LO, 12-LO and 15-LOa have been carried out allowing kinetic analysis...

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“…At any rate, it would be arbitrary to exclude now that the decline in spectrin from young to old RBCs could be due to extensive proteolysis via one or more of the proteolytic pathways that exist in mature RBCs, from the proteasome-based [33] to calpain- [34] or, perhaps, caspase-dependent [35]. Future work will be aimed at comparing the pattern of spectrin fragments observed here to the pattern of fragments obtained by limited proteolysis of RBC ghosts with the above-mentioned proteolytic activities.…”

Section: Discussionmentioning

confidence: 99%

Spectrin and Other Membrane-Skeletal Components in Human Red Blood Cells of Different Age

Ciana

Achilli

Minetti³

2017

Cell Physiol Biochem

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Background: Old human red blood cells (RBCs) have a reduced surface area with respect to young RBCs. If this decrease occurred through the release of vesicles similar to the spectrin-free vesicles that are shed in vitro under different experimental conditions or during storage, there would be no decrease of membrane-skeleton, but only of lipid bilayer surface area, during RBC ageing in vivo. However, we observed a decrease in spectrin and other membrane-skeletal proteins in old RBCs. Because RBCs contain components of the ubiquitin-proteasome system and other hydrolytic systems for protein degradation, we asked whether increased membrane-skeleton fragments could be detected in older RBCs. Methods: Four different anti-spectrin antibodies and an antibody anti-ubiquitin conjugates were used to analyse, by Western blotting, fragments of spectrin and other proteins in RBCs of different age separated in density gradients and characterized for their protein 4.1a/4.1b ratio as a cell age parameter. Results: spectrin fragments do exist in RBCs of all ages, they represent a minute fraction of all spectrin, are membrane-bound and not cytoplasmic and do not increase with cell age. Besides spectrin, other membrane-skeletal components decrease with cell age. Conclusion: Observed results challenge the commonly accepted view that decrease in cell membrane throughout RBC life in vivo occurs via the release of spectrin-free vesicles.

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Mechanisms of perturbation of erythrocyte calcium homeostasis in favism

Cited by 36 publications

References 28 publications

Cation channels trigger apoptotic death of erythrocytes

Cation channels trigger apoptotic death of erythrocytes

Differential characteristics of human 15‐lipoxygenase isozymes and a novel splice variant of 15S‐lipoxygenase

Spectrin and Other Membrane-Skeletal Components in Human Red Blood Cells of Different Age

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