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BioMed Research International
Volume 2015 (2015), Article ID 965271, 14 pages
http://dx.doi.org/10.1155/2015/965271
Research Article

Regulation of Angiogenic Functions by Angiopoietins through Calcium-Dependent Signaling Pathways

1Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy
2Institute of Vegetative Anatomy, Charité Universitätsmedizin, Neuromuscular Group, 10115 Berlin, Germany

Received 19 December 2014; Revised 12 February 2015; Accepted 15 February 2015

Academic Editor: Jie-Hui Li

Copyright © 2015 Irene Pafumi 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

Angiopoietins are vascular factors essential for blood vessel assembly and correct organization and maturation. This study describes a novel calcium-dependent machinery activated through Angiopoietin-1/2-Tie receptor system in HUVECs monolayer. Both cytokines were found to elicit intracellular calcium mobilization. Targeting intracellular Ca2+ signaling, antagonizing IP3 with 2-APB or cADPR with 8Br-cADPR, was found to modulate in vitro angiogenic responses to Angiopoietins in a specific way. 2-APB and 8Br-cADPR impaired the phosphorylation of AKT and FAK induced by Ang-1 and Ang-2. On the other hand, phosphorylation of ERK1/2 and p38, as well as cell proliferation, was not affected by either inhibitor. The ability of ECs to migrate following Angs stimulation, evaluated by “scratch assay,” was reduced by either 2-APB or 8Br-cADPR following Ang-2 stimulation and only slightly affected by 2-APB in cells stimulated with Ang-1. These results identify a novel calcium-dependent machinery involved in the complex interplay regulating angiogenic processes showing that IP3- and cADPR-induced Ca2+ release specifically regulates distinct Angs-mediated angiogenic steps.