This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 104/1/32    most recent CIRCRESAHA.108.182261v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pula, G. Articles by Mayr, M. Search for Related Content PubMed PubMed Citation Articles by Pula, G. Articles by Mayr, M. Related Collections Angiogenesis Functional genomics Growth factors/cytokines Other Vascular biology

(Circulation Research. 2009;104:32.)
© 2009 American Heart Association, Inc.

Molecular Medicine

Proteomics Identifies Thymidine Phosphorylase As a Key Regulator of the Angiogenic Potential of Colony-Forming Units and Endothelial Progenitor Cell Cultures

Giordano Pula^*, Ursula Mayr^*, Colin Evans, Marianna Prokopi, Dina S. Vara, Xiaoke Yin, Zoe Astroulakis, Qingzhong Xiao, Jonathan Hill, Qingbo Xu, Manuel Mayr

From the Cardiovascular Division, King’s College London School of Medicine, King’s College London, United Kingdom.

Correspondence to Manuel Mayr, Cardiovascular Division, BHF Centre, King’s College, London, 125 Coldharbour Lane, London SE5 9NU, UK. E-mail manuel.mayr{at}kcl.ac.uk

Endothelial progenitor cell (EPC) cultures and colony-forming units (CFUs) have been extensively studied for their therapeutic and diagnostic potential. Recent data suggest a role for EPCs in the release of proangiogenic factors. To identify factors secreted by EPCs, conditioned medium from EPC cultures and CFUs was analyzed using a matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometer combined with offline peptide separation by nanoflow liquid chromatography. Results were verified by RT-PCR and multiplex cytokine assays and complemented by a cellular proteomic analysis of cultured EPCs and CFUs using difference in-gel electrophoresis. This extensive proteomic analysis revealed the presence of the proangiogenic factor thymidine phosphorylase (TP). Functional experiments demonstrated that inhibition of TP by 5-bromo-6-amino-uracil or gene silencing resulted in a significant increase in basal and oxidative stress-induced apoptosis, whereas supplementation with 2-deoxy-D-ribose-1-phosphate (dRP), the enzymatic product of TP, abrogated this effect. Moreover, dRP produced in EPC cultures stimulated endothelial cell migration in a paracrine manner, as demonstrated by gene-silencing experiments in transmigration and wound repair assays. RGD peptides and inhibitory antibodies to integrin vβ3 attenuated the effect of conditioned medium from EPC cultures on endothelial migration. Finally, the effect of TP on angiogenesis was investigated by implantation of Matrigel plugs in mice. In these in vivo experiments, dRP strongly promoted neovascularization. Our data support the concept that EPCs exert their proangiogenic activity in a paracrine manner and demonstrate a key role of TP activity in their survival and proangiogenic potential.

Key Words: angiogenesis • endothelium • progenitor cells • proteomics • vascular biology

This article has been cited by other articles:

				H. Lu, R. S. Klein, and E. L. Schwartz Antiangiogenic and Antitumor Activity of 6-(2-Aminoethyl)Amino-5-Chlorouracil, a Novel Small-Molecule Inhibitor of Thymidine Phosphorylase, in Combination with the Vascular Endothelial Growth Factor-Trap Clin. Cancer Res., August 15, 2009; 15(16): 5136 - 5144. [Abstract] [Full Text] [PDF]

				M. Prokopi, G. Pula, U. Mayr, C. Devue, J. Gallagher, Q. Xiao, C. M. Boulanger, N. Westwood, C. Urbich, J. Willeit, et al. Proteomic analysis reveals presence of platelet microparticles in endothelial progenitor cell cultures Blood, July 16, 2009; 114(3): 723 - 732. [Abstract] [Full Text] [PDF]