NADPH Oxidase Nox 2 Is Required for Hypoxia-Induced Mobilization of Endothelial Progenitor Cells

Content Provider	Semantic Scholar
Author	Schröder, Katrin Kohnen, Andreas Aicher, Alexandra Liehn, Elisa A. Büchse, Tom Stein, Stefan Weber, Christian Dimmeler, Stefanie Brandes, Ralf P.
Copyright Year	2009
Abstract	Rationale: Endothelial progenitor cells (EPCs, defined as sca-1 flk lin mononuclear blood cells) contribute to vascular repair. The role of hypoxia and reactive oxygen species (ROS) in mobilization and function of these cells is incompletely understood. Objective: We studied the contribution of the NADPH oxidase Nox2, an important vascular source of ROS in this context. Methods and Results: Hypoxia (10% oxygen) induced the mobilization of EPCs in wild-type (WT) and Nox1 but not in Nox2 knockout (Nox2 ) mice. As erythropoietin (EPO) is known to induce EPC mobilization, we focused on this hormone. EPO induced the mobilization of EPCs in WT and Nox1 but not Nox2 animals. Transplantation of bone marrow from Nox2 mice into WT-mice blocked mobilization in response to hypoxia and EPO, whereas transplantation of WT bone marrow into Nox2 mice restored mobilization. Reendothelialization of the injured mouse carotid artery was enhanced by hypoxia as well as by EPO, and this effect was not observed in Nox2 mice or after transplantation of Nox2 bone marrow. In cultured EPCs from WT but not Nox2 mice, EPO induced ROS production, migration, and proliferation. EPO signaling involves the STAT5 transcription factor. EPO-induced STAT5-dependent reporter gene expression was absent in Nox2-deficient cells. siRNA against the redox-sensitive phosphatase SHP-2 restored EPO-mediated STAT5 induction and inhibition of SHP-2 restored EPO-induced migration in Nox2-deficient cells Conclusions: We conclude that Nox2-derived ROS inactivate SHP-2 and thereby facilitate EPO signaling in EPCs to promote hypoxia-induced mobilization and vascular repair by these cells. (Circ Res. 2009;105:00-00.)
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Alternate Webpage(s)	http://circres.ahajournals.org/content/circresaha/105/6/537.full.pdf?download=true
Alternate Webpage(s)	http://circres.ahajournals.org/content/circresaha/early/2009/08/13/CIRCRESAHA.109.205138.full.pdf?cited-by=yes&legid=circresaha%3BCIRCRESAHA.109.205138v1
Alternate Webpage(s)	http://circres.ahajournals.org/content/circresaha/105/6/537.full.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article