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BioMed Research International
Volume 2014, Article ID 413708, 11 pages
http://dx.doi.org/10.1155/2014/413708
Research Article

The Influence of Simulated Microgravity on Purinergic Signaling Is Different between Individual Culture and Endothelial and Smooth Muscle Cell Coculture

1Department of Natural Sciences, Bonn-Rhine-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
2Institute of Pharmacology and Medical Chemistry, University of Dusseldorf, 40225 Dusseldorf, Germany
3Institute of Aerospace Medicine, German Aerospace Center, 51147 Cologne, Germany

Received 25 April 2014; Revised 30 June 2014; Accepted 23 July 2014; Published 28 August 2014

Academic Editor: Monica Monici

Copyright © 2014 Yu Zhang et al. 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

Exposure to microgravity conditions causes cardiovascular deconditioning in astronauts during spaceflight. Until now, no specific drugs are available for countermeasure, since the underlying mechanism is largely unknown. Endothelial cells (ECs) and smooth muscle cells (SMCs) play key roles in various vascular functions, many of which are regulated by purinergic 2 (P2) receptors. However, their function in ECs and SMCs under microgravity conditions is still unclear. In this study, primary ECs and SMCs were isolated from bovine aorta and verified with specific markers. We show for the first time that the P2 receptor expression pattern is altered in ECs and SMCs after 24 h exposure to simulated microgravity using a clinostat. However, conditioned medium compensates this change in specific P2 receptors, for example, P2X7. Notably, P2 receptors such as P2X7 might be the important players during the paracrine interaction. Additionally, ECs and SMCs secreted different cytokines under simulated microgravity, leading into a pathogenic proliferation and migration. In conclusion, our data indicate P2 receptors might be important players responding to gravity changes in ECs and SMCs. Since some artificial P2 receptor ligands are applied as drugs, it is reasonable to assume that they might be promising candidates against cardiovascular deconditioning in the future.