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Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum

In human erythrocytes (h-RBCs) various stimuli induce increases in [cAMP] that trigger ATP release. The resulting pattern of extracellular ATP accumulation (ATPe kinetics) depends on both ATP release and ATPe degradation by ectoATPase activity. In this study we evaluated ATPe kinetics from primary c...

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Autores principales: Alvarez, Cora Lilia, Schachter, Julieta, de Sá Pinheiro, Ana Acacia, Silva, Leandro de Souza, Verstraeten, Sandra Viviana, Persechini, Pedro Muanis, Schwarzbaum, Pablo Julio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032238/
https://www.ncbi.nlm.nih.gov/pubmed/24858837
http://dx.doi.org/10.1371/journal.pone.0096216
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author Alvarez, Cora Lilia
Schachter, Julieta
de Sá Pinheiro, Ana Acacia
Silva, Leandro de Souza
Verstraeten, Sandra Viviana
Persechini, Pedro Muanis
Schwarzbaum, Pablo Julio
author_facet Alvarez, Cora Lilia
Schachter, Julieta
de Sá Pinheiro, Ana Acacia
Silva, Leandro de Souza
Verstraeten, Sandra Viviana
Persechini, Pedro Muanis
Schwarzbaum, Pablo Julio
author_sort Alvarez, Cora Lilia
collection PubMed
description In human erythrocytes (h-RBCs) various stimuli induce increases in [cAMP] that trigger ATP release. The resulting pattern of extracellular ATP accumulation (ATPe kinetics) depends on both ATP release and ATPe degradation by ectoATPase activity. In this study we evaluated ATPe kinetics from primary cultures of h-RBCs infected with P. falciparum at various stages of infection (ring, trophozoite and schizont stages). A “3V” mixture containing isoproterenol (β-adrenergic agonist), forskolin (adenylate kinase activator) and papaverine (phosphodiesterase inhibitor) was used to induce cAMP-dependent ATP release. ATPe kinetics of r-RBCs (ring-infected RBCs), t-RBCs (trophozoite-infected RBCs) and s-RBCs (schizont-infected RBCs) showed [ATPe] to peak acutely to a maximum value followed by a slower time dependent decrease. In all intraerythrocytic stages, values of ΔATP(1) (difference between [ATPe] measured 1 min post-stimulus and basal [ATPe]) increased nonlinearly with parasitemia (from 2 to 12.5%). Under 3V exposure, t-RBCs at parasitemia 94% (t94-RBCs) showed 3.8-fold higher ΔATP(1) values than in h-RBCs, indicative of upregulated ATP release. Pre-exposure to either 100 µM carbenoxolone, 100 nM mefloquine or 100 µM NPPB reduced ΔATP(1) to 83–87% for h-RBCs and 63–74% for t94-RBCs. EctoATPase activity, assayed at both low nM concentrations (300–900 nM) and 500 µM exogenous ATPe concentrations increased approx. 400-fold in t94-RBCs, as compared to h-RBCs, while intracellular ATP concentrations of t94-RBCs were 65% that of h-RBCs. In t94-RBCs, production of nitric oxide (NO) was approx. 7-fold higher than in h-RBCs, and was partially inhibited by L-NAME pre-treatment. In media with L-NAME, ΔATP(1) values were 2.7-times higher in h-RBCs and 4.2-times higher in t94-RBCs, than without L-NAME. Results suggest that P. falciparum infection of h-RBCs strongly activates ATP release via Pannexin 1 in these cells. Several processes partially counteracted ATPe accumulation: an upregulated ATPe degradation, an enhanced NO production, and a decreased intracellular ATP concentration.
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spelling pubmed-40322382014-05-28 Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum Alvarez, Cora Lilia Schachter, Julieta de Sá Pinheiro, Ana Acacia Silva, Leandro de Souza Verstraeten, Sandra Viviana Persechini, Pedro Muanis Schwarzbaum, Pablo Julio PLoS One Research Article In human erythrocytes (h-RBCs) various stimuli induce increases in [cAMP] that trigger ATP release. The resulting pattern of extracellular ATP accumulation (ATPe kinetics) depends on both ATP release and ATPe degradation by ectoATPase activity. In this study we evaluated ATPe kinetics from primary cultures of h-RBCs infected with P. falciparum at various stages of infection (ring, trophozoite and schizont stages). A “3V” mixture containing isoproterenol (β-adrenergic agonist), forskolin (adenylate kinase activator) and papaverine (phosphodiesterase inhibitor) was used to induce cAMP-dependent ATP release. ATPe kinetics of r-RBCs (ring-infected RBCs), t-RBCs (trophozoite-infected RBCs) and s-RBCs (schizont-infected RBCs) showed [ATPe] to peak acutely to a maximum value followed by a slower time dependent decrease. In all intraerythrocytic stages, values of ΔATP(1) (difference between [ATPe] measured 1 min post-stimulus and basal [ATPe]) increased nonlinearly with parasitemia (from 2 to 12.5%). Under 3V exposure, t-RBCs at parasitemia 94% (t94-RBCs) showed 3.8-fold higher ΔATP(1) values than in h-RBCs, indicative of upregulated ATP release. Pre-exposure to either 100 µM carbenoxolone, 100 nM mefloquine or 100 µM NPPB reduced ΔATP(1) to 83–87% for h-RBCs and 63–74% for t94-RBCs. EctoATPase activity, assayed at both low nM concentrations (300–900 nM) and 500 µM exogenous ATPe concentrations increased approx. 400-fold in t94-RBCs, as compared to h-RBCs, while intracellular ATP concentrations of t94-RBCs were 65% that of h-RBCs. In t94-RBCs, production of nitric oxide (NO) was approx. 7-fold higher than in h-RBCs, and was partially inhibited by L-NAME pre-treatment. In media with L-NAME, ΔATP(1) values were 2.7-times higher in h-RBCs and 4.2-times higher in t94-RBCs, than without L-NAME. Results suggest that P. falciparum infection of h-RBCs strongly activates ATP release via Pannexin 1 in these cells. Several processes partially counteracted ATPe accumulation: an upregulated ATPe degradation, an enhanced NO production, and a decreased intracellular ATP concentration. Public Library of Science 2014-05-23 /pmc/articles/PMC4032238/ /pubmed/24858837 http://dx.doi.org/10.1371/journal.pone.0096216 Text en © 2014 Alvarez et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Alvarez, Cora Lilia
Schachter, Julieta
de Sá Pinheiro, Ana Acacia
Silva, Leandro de Souza
Verstraeten, Sandra Viviana
Persechini, Pedro Muanis
Schwarzbaum, Pablo Julio
Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title_full Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title_fullStr Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title_full_unstemmed Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title_short Regulation of Extracellular ATP in Human Erythrocytes Infected with Plasmodium falciparum
title_sort regulation of extracellular atp in human erythrocytes infected with plasmodium falciparum
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032238/
https://www.ncbi.nlm.nih.gov/pubmed/24858837
http://dx.doi.org/10.1371/journal.pone.0096216
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