Oxidative stress and protective mechanisms in erythrocytes in relation to Plasmodium vinckei load.

Stocker, Roland; Hunt, Nicholas H.; Buffinton, Gary D.; Weidemann, Maurice J.; Lewis-Hughes, Peter H.; Clark, Ian A.

doi:10.1073/pnas.82.2.548

Cited by 76 publications

(38 citation statements)

References 29 publications

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“…When BODIPY 581/591-PC was used to probe P. falciparum-infected RBCs, we found an increase in the level of conversion of the chromophore to the oxidized form as the parasite matures. These data are consistent with previous studies indicating an overall increase in oxidative damage in infected RBCs (2,22,60), although these previous results could have been affected by inadvertent oxidation during sample work up (61). The increase in oxidative stress experienced by trophozoite-infected RBCs would be expected to increase their susceptibility to antimalarial drugs such as chloroquine that increase the levels of free FP-FeIII and are likely to exacerbate oxidative stress.…”

Section: Discussionsupporting

confidence: 82%

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A phosphatidylcholine‐BODIPY 581/591 conjugate allows mapping of oxidative stress in P. falciparum‐infected erythrocytes

Klonis

Suarna

et al. 2009

Cytometry Pt A

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The chromophore, BODIPY 581/591, has an extended conjugated system that reacts with oxygen centered-radicals leading to changes in its spectral characteristics. Fatty acid-conjugated BODIPY 581/591 transfers readily between membrane bilayers and can be used as a sensor of oxidative stress in cell populations. We report here the use of a phosphatidylcholine (PC) derivative of BODIPY 581/591, which transfers much less rapidly between membranes. This allows the analysis of oxidative stress in individual cells and in different compartments within cells. Quantitative imaging and flow cytometry were used to measure the ratio of fully conjugated to oxidized probe in model systems and in Plasmodium falciparum-infected erythrocytes. We observed an increase in the oxidation of the parasite-associated BODIPY 581/591-PC as the intraerythrocytic parasite matures. By contrast, BODIPY 581/591-PC associated with the erythrocyte membrane experiences a low level of oxidation even in the later stages of parasite development. Treatment with a pro-oxidant compound caused increased oxidation of the probe in the parasite compartment, but less so in the host cell membrane. Conversely, treatment with ferricyanide increases oxidation of the probe in the erythrocyte cell membrane but does not inhibit parasite growth. Chromatographic analysis of the lipids in infected erythrocytes shows no evidence for loss of a-tocopherol or the accumulation of lipid hydroperoxides indicating that, despite the increased oxidative stress, the parasite membranes remain protected from substantial lipid oxidation. We have established BODIPY 581/591-PC as a useful probe of the spatial distribution of oxidative stress in P. falciparum-infected erythrocytes; however, the probe appears to be more sensitive to oxidative damage than endogenous lipids. ' 2009 International Society for Advancement of Cytometry Key terms malaria; Plasmodium falciparum; oxidative stress; BODIPY 581/591-PC; lipid oxidation OXIDATIVE damage to protein and membrane components plays important roles in various diseases and in the aging process (1), and a number of methods have been developed for measuring oxidative stress in cellular systems. In some studies, the levels of oxidized lipids and proteins have been measured directly (2,3). In other studies, secondary reaction products, such as malondialdehyde, have been used as a surrogate measure of lipid oxidation (4). These approaches offer useful insights into oxidative events; however, they usually require physical disruption of the system under investigation.Recently, fluorescence-based probes of oxidative stress have gained popularity as relatively nonperturbing sensors of cellular stresses (5-7). The fatty acid (FA) analogue, cis-paranaric acid (8), has been used as an oxidant-sensitive fluorophore; however, its fluorescence in the UV range is a disadvantage in some applications. BODIPY 581/591 is an alternative probe that can be excited in the visible range and

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Section: Discussionsupporting

confidence: 82%

“…By contrast, other studies find an increase in tocopherol levels and no evidence for lipid oxidation, unless additional oxidative stress is applied (2,23). In this work, we have used BODIPY 581/591-PC and novel imaging and flow cytometry formats to reexamine oxidative stress in P. falciparum-infected RBCs.…”

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confidence: 99%

A phosphatidylcholine‐BODIPY 581/591 conjugate allows mapping of oxidative stress in P. falciparum‐infected erythrocytes

Klonis

Suarna

et al. 2009

Cytometry Pt A

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“…Where possible, numbers are given for the first and last amino acid residue of each secondary-structure element. that several factors contribute to the formation of methemoglobin during plasmodial infection, including the acidic pH of the plasmodial food vacuole, oxidative damage within infected erythrocytes (51,52), and the reduced activity of NADH-methemoglobin reductase (53). A significantly increased methemoglobin content in the range of 20 -42% has been detected in the plasmodial food vacuole compared with 0.6 -1.0% in uninfected erythrocytes (51).…”

Section: Discussionmentioning

confidence: 99%

Structural and Functional Characterization of Falcipain-2, a Hemoglobinase from the Malarial Parasite Plasmodium falciparum

Hogg

Nagarajan

Herzberg

et al. 2006

Journal of Biological Chemistry

110

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Malaria is caused by protozoan erythrocytic parasites of the Plasmodium genus, with Plasmodium falciparum being the most dangerous and widespread disease-causing species. Falcipain-2 (FP-2) of P. falciparum is a papain-family (C1A) cysteine protease that plays an important role in the parasite life cycle by degrading erythrocyte proteins, most notably hemoglobin. Inhibition of FP-2 and its paralogues prevents parasite maturation, suggesting these proteins may be valuable targets for the design of novel antimalarial drugs, but lack of structural knowledge has impeded progress toward the rational discovery of potent, selective, and efficacious inhibitors. As a first step toward this goal, we present here the crystal structure of mature FP-2 at 3.1 Å resolution, revealing novel structural features of the FP-2 subfamily proteases including a dynamic ␤-hairpin hemoglobin binding motif, a flexible N-terminal ␣-helical extension, and a unique active-site cleft. We also demonstrate by biochemical methods that mature FP-2 can proteolytically process its own precursor in trans at neutral to weakly alkaline pH, that the binding of hemoglobin to FP-2 is strictly pH-dependent, and that FP-2 preferentially binds methemoglobin over hemoglobin. Because the specificity and proteolytic activity of FP-2 toward its multiple targets appears to be pH-dependent, we suggest that environmental pH may play an important role in orchestrating FP-2 function over the different life stages of the parasite. Moreover, it appears that selectivity of FP-2 for methemoglobin may represent an evolutionary adaptation to oxidative stress conditions within the host cell.

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“…Superoxide dismutase (EC 1.15.1.1; SOD) catalyses the dismutation of superoxide anions (02-) to H 2 0 2 and O2 while catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.1 1.1.9; GPx) break down H 2 0 2 to water and 0 2 (Fairfield et al 1988). Several studies have reported on the antioxidantdefence enzymes in plasmodium-infected and uninfected erythrocytes (Suthipark et al 1982;Seth et al 1985;Stocker et al 1985). However, the role of riboflavin has not been studied.…”

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confidence: 99%

Glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities in riboflavin-deficient rats infected with Plasmodium berghei malaria

Adelekan

Thurnham

1998

Br J Nutr

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Riboflavin deficiency interferes with the growth and multiplication of malaria parasites as well as the host response to malaria. The objective of the present work was to determine the effects of riboflavin deficiency on erythrocyte glutathione peroxidase (EC 1.1 1.1.9; GPx) and superoxide dismutase (EC 1.15.1.1; SOD) in rats infected with Plasmodium berghei malaria. Riboflavin in its co-enzyme form, FAD, is required by glutathione reductase (EC 1.6.4.1) to regenerate GSH and GSH is an important cellular antioxidant both in its own right and also as a substrate for the enzyme GPx. Weanling rats were deprived of riboflavin for 8 weeks before intraperitoneal injection of 1 x lo6 P. berghei parasites. Control animals were weight-matched to the respective riboflavin-deficient group. At 10 d post-infection, parasite counts were higher in the weightmatched control group than the riboflavin-deficient group (P = 0.004). GPx activity was higher in erythrocytes of rats parasitized with P. berghei than comparable non-infected rats regardless of riboflavin status (P < 0.05). As mature erythrocytes do not synthesize new protein, the higher GPx activities were probably due to the presence of the parasite protein. In erythrocytes from riboflavin-deficient rats, GPx activity tended to be lower than in those rats fed on diets adequate in riboflavin (weight-matched controls) whether parasitized or not, but the difference was not significant. Neither riboflavin deficiency nor malaria had any effect on erythrocyte SOD activity.It was concluded that riboflavin deficiency has no marked effect on erythrocyte GPx or SOD activity in the rat. Riboflavin: Malaria: Glutathione peroxidase: Superoxide dismutase

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Oxidative stress and protective mechanisms in erythrocytes in relation to Plasmodium vinckei load.

Cited by 76 publications

References 29 publications

A phosphatidylcholine‐BODIPY 581/591 conjugate allows mapping of oxidative stress in P. falciparum‐infected erythrocytes

A phosphatidylcholine‐BODIPY 581/591 conjugate allows mapping of oxidative stress in P. falciparum‐infected erythrocytes

Structural and Functional Characterization of Falcipain-2, a Hemoglobinase from the Malarial Parasite Plasmodium falciparum

Glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities in riboflavin-deficient rats infected with Plasmodium berghei malaria

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