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Molecular Medicine

, Volume 14, Issue 1–2, pp 28–35 | Cite as

The Antithrombotic Effect of Angiotensin-(1-7) Involves Mas-Mediated NO Release from Platelets

  • Rodrigo Araújo Fraga-Silva
  • Sergio Veloso Brant Pinheiro
  • Andrey Christian Costa Gonçalves
  • Nathalia Alenina
  • Michael Bader
  • Robson Augusto Souza Santos
Research Article

Abstract

The antithrombotic effect of angiotensin(Ang)-(1-7) has been reported, but the mechanism of this effect is not known. We investigated the participation of platelets and receptor Mas-related mechanisms in this action. We used Western blotting to test for the presence of Mas protein in rat platelets and used fluorescent-labeled FAM-Ang-(1-7) to determine the specific binding for Ang-(1-7) and its displacement by the receptor Mas antagonist A-779 in rat platelets and in Mas−/− and Mas+/+ mice platelets. To test whether Ang-(1-7) induces NO release from platelets, we used the NO indicator DAF-FM. In addition we examined the role of Mas in the Ang-(1-7) antithrombotic effect on induced thrombi in the vena cava of male Mas/ and Mas+/+ mice. The functional relevance of Mas in hemostasis was evaluated by determining bleeding time in Mas+/+ and Mas/ mice. We observed the presence of Mas protein in platelets, as indicated by Western Blot, and displacement of the binding of fluorescent Ang-(1-7) to rat platelets by A-779. Furthermore, in Mas+/+ mouse platelets we found specific binding for Ang-(1-7), which was absent in Mas/ mouse platelets. Ang-(1-7) released NO from rat and Mas+/+ mouse platelets, and A-779 blocked this effect. The NO release stimulated by Ang-(1-7) was abolished in Mas/ mouse platelets. Ang-(1-7) inhibited thrombus formation in Mas+/+ mice. Strikingly, this effect was abolished in Mas/ mice. Moreover, Mas deficiency resulted in a significant decrease in bleeding time (8.50 ± 1.47 vs. 4.28 ± 0.66 min). This study is the first to show the presence of Mas protein and specific binding for Ang-(1-7) in rat and mouse platelets. Our data also suggest that the Ang-(1-7) antithrombotic effect involves Mas-mediated NO release from platelets. More importantly, we showed that the antithrombotic effect of Ang-(1-7) in vivo is Mas dependent and that Mas is functionally important in hemostasis.

Notes

Acknowledgments

This work was supported in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), and Programa de Apoio a Núcleos de Excelência (FAPEMIG/CNPq-PRONEX). RA Fraga-Silva is the recipient of support from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

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Copyright information

© Feinstein Institute for Medical Research 2008

Authors and Affiliations

  • Rodrigo Araújo Fraga-Silva
    • 1
  • Sergio Veloso Brant Pinheiro
    • 1
  • Andrey Christian Costa Gonçalves
    • 2
  • Nathalia Alenina
    • 2
  • Michael Bader
    • 2
  • Robson Augusto Souza Santos
    • 1
    • 3
  1. 1.Department of PhysiologyFederal University of Minas GeraisBelo Horizonte, Minas GeraisBrasil
  2. 2.Max-Delbrück Center for Molecular MedicineBerlinGermany
  3. 3.Robson Augusto Souza dos Santos, Departamento de Fisiologia e Biofísica6627-ICB-UFMGBelo Horizonte, MGBrasil

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