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Mediators of Inflammation
Volume 2014 (2014), Article ID 760368, 10 pages
http://dx.doi.org/10.1155/2014/760368
Research Article

Ouabain Affects the Expression of Activation Markers, Cytokine Production, and Endocytosis of Human Monocytes

Laboratório de Imunologia Tumoral, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, H2003 Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil

Received 18 January 2014; Accepted 3 March 2014; Published 8 May 2014

Academic Editor: Hidde Bult

Copyright © 2014 Mariana Pires Teixeira and Vivian Mary Rumjanek. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Ouabain is a steroid capable of binding to and inhibiting Na+,-K+-ATPase. Studies have demonstrated some actions of ouabain on immune cells, which indicated both pro- and anti-inflammatory properties of this molecule. Nevertheless, its effects on human monocytes are still poorly understood. Thus, the present work investigated effects of ouabain in the activation and function of human adherent monocytes. Our results show that there is an increase in intracellular calcium levels already 5 minutes following monocyte treatment with 10−7 M of ouabain. Furthermore, monocytes expressed increased amounts of surface activation markers such as CD69, HLA-DR, CD86, and CD80 and also presented an augmented endocytic activity of dextran-FITC particles after 24 hours of culture in the presence of ouabain. However, monocytes treated with ouabain did not have an increased stimulatory capacity in allogeneic mixed leukocyte reaction. Ouabain-treated monocytes produced higher levels of IL-1β and TNF-α as reported before. A novel observation was the fact that ouabain induced IL-10 and VEGF as well. Collectively, these results suggest that ouabain impacts monocyte activation and modulates monocyte functions, implying that this steroid could act as an immunomodulator of these cells.