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Original Research Articles

Cellular stress conditions are reflected in the protein and RNA content of endothelial cell-derived exosomes

, , , , , , , & show all
Article: 18396 | Received 16 Mar 2012, Accepted 21 Mar 2012, Published online: 15 Apr 2012
 

Abstract

Background: The healthy vascular endothelium, which forms the barrier between blood and the surrounding tissues, is known to efficiently respond to stress signals like hypoxia and inflammation by adaptation of cellular physiology and the secretion of (soluble) growth factors and cytokines. Exosomes are potent mediators of intercellular communication. Their content consists of RNA and proteins from the cell of origin, and thus depends on the condition of these cells at the time of exosome biogenesis. It has been suggested that exosomes protect their target cells from cellular stress through the transfer of RNA and proteins. We hypothesized that endothelium-derived exosomes are involved in the endothelial response to cellular stress, and that exosome RNA and protein content reflect the effects of cellular stress induced by hypoxia, inflammation or hyperglycemia. Methods: We exposed cultured endothelial cells to different types of cellular stress (hypoxia, TNF-α-induced activation, high glucose and mannose concentrations) and compared mRNA and protein content of exosomes produced by these cells by microarray analysis and a quantitative proteomics approach. Results: We identified 1,354 proteins and 1,992 mRNAs in endothelial cell-derived exosomes. Several proteins and mRNAs showed altered abundances after exposure of their producing cells to cellular stress, which were confirmed by immunoblot or qPCR analysis. Conclusion: Our data show that hypoxia and endothelial activation are reflected in RNA and protein exosome composition, and that exposure to high sugar concentrations alters exosome protein composition only to a minor extend, and does not affect exosome RNA composition.

To access the supplementary material to this article: Tables SI-SIV and Figures S1-2, please see Supplementary files under Article Tools online.

Acknowledgements

B.W.M.v.B. is supported by the Netherlands Foundation for Cardiovascular excellence (Grant No. 003/08) and The Netherlands Organization for Scientific Research (NGI/ZonMW Horizon project 935190280) and a UMC Utrecht Focus and Massa grant (Grant No. DIGD-DGK-DHL); M.C.V. is supported by The Netherlands Organization for Scientific Research (ZonMW VIDI grant), the Netherlands Institute for Regenerative Medicine and a UMC Utrecht Focus and Massa grant (Grant No. DIGD-DGK-DHL); O.G.d.J. is supported by the Netherlands Institute for Regenerative Medicine. Y.C. and M.G. are supported by the National Heart, Lung and Blood intramural program of the National Institutes of Health. P.V. and R.M.S. are supported by The European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement (Grant No. 260627). We thank J. Brummelman and P.M. de Bree for excellent technical assistance.