Protein Z Exerts Pro-Angiogenic Effects and Upregulates CXCR4: e113554

• Published in: PloS one 2014-12, Vol.9 (12)
• Main Authors: Butschkau, Antje, Wagner, Nana-Maria, Genz, Berit, Vollmar, Brigitte
• Format: Article
• Language: English
• Subjects: Adenoviridae
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0113554

Objective Protein Z (PZ) is a vitamin K-dependent coagulation factor without catalytic activity. Evidence points towards PZ as an independent risk factor for the occurrence of human peripheral arterial disease. However, the role of PZ in ischemia-driven angiogenesis and vascular healing processes has not been elucidated so far. Approach Angiogenic potency of PZ was assessed in established in vitro assays using endothelial cells. PZ-deficient (PZ-/-) mice and their wild-type littermates (PZ+/+) were subjected to hindlimb ischemia. Furthermore, PZ-/- mice were exposed to PZ expressing adenovirus (AdV-PZ) or control adenovirus (AdV-GFP). In an additional set of animals, PZ-/- mice were exposed to AdV-PZ and AdV-GFP, each in combination with the CXCR4 antagonist AMD3100. Results In vitro, PZ stimulated migratory activity and capillary-like tube formation of endothelial cells comparable to SDF-1. PZ-/- mice exhibited diminished hypoxia-driven neovascularization and reperfusion in post-ischemic hindlimbs, which was restored by adenoviral gene transfer up to levels seen in PZ+/+ mice. The stimulatory impact of PZ on endothelial cells in vitro was abolished by siRNA targeting against PZ and PZ was not able to restore reduced migration after knock-down of CXCR4. The increased surface expression of CXCR4 on PZ-stimulated endothelial cells and the abrogated restoration of PZ-/- mice via AdV-PZ after concomitant treatment with the CXCR4 antagonist AMD3100 supports the idea that PZ mediates angiogenesis via a G-protein coupled pathway and involves the SDF-1/CXCR4 axis. This is underlined by the fact that addition of the G-protein inhibitor PTX to PZ-stimulated endothelial cells abolished the effect of PZ on capillary-like tube formation. Conclusions The results of the current study reveal a role of PZ in ischemia-induced angiogenesis, which involves a G-protein coupled pathway and a raised surface expression of CXCR4. Our findings thereby extend the involvement of PZ from the coagulation cascade to a beneficial modulation of vascular homeostasis.