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OBJECTIVE: Asymmetrical dimethylarginine (ADMA) is a nitric oxide synthase (NOS) inhibitor and cardiovascular risk factor associated with angiogenic disorders. Enzymes metabolising ADMA, dimethylarginine dimethylaminohydrolases (DDAH) promote angiogenesis, but the mechanisms are not clear. We hypothesized that ADMA/DDAH modifies endothelial responses to vascular endothelial growth factor (VEGF) by affecting activity of Rho GTPases, regulators of actin polymerization, and focal adhesion dynamics. METHODS AND RESULTS: The effects of ADMA on VEGF-induced endothelial cell motility, focal adhesion turnover, and angiogenesis were studied in human umbilical vein endothelial cells (HUVECs) and DDAH I heterozygous knockout mice. ADMA inhibited VEGF-induced chemotaxis in vitro and angiogenesis in vitro and in vivo in an NO-dependent way. ADMA effects were prevented by overexpression of DDAH but were not associated with decreased proliferation, increased apoptosis, or changes in VEGFR-2 activity or expression. ADMA inhibited endothelial cell polarization, protrusion formation, and decreased focal adhesion dynamics, resulting from Rac1 inhibition after decrease in phosphorylation of vasodilator stimulated phosphoprotein (VASP). Constitutively active Rac1, and to a lesser extent dominant negative RhoA, abrogated ADMA effects in vitro and in vivo. CONCLUSIONS: The ADMA/DDAH pathway regulates VEGF-induced angiogenesis in an NO- and Rac1-dependent manner.

Original publication

DOI

10.1161/ATVBAHA.109.194035

Type

Journal article

Journal

Arterioscler Thromb Vasc Biol

Publication Date

12/2009

Volume

29

Pages

2117 - 2124

Keywords

Amidohydrolases, Animals, Apoptosis, Arginine, Cell Adhesion Molecules, Cell Polarity, Cell Proliferation, Cells, Cultured, Chemotaxis, Endothelial Cells, Focal Adhesions, Humans, In Vitro Techniques, Mice, Mice, Knockout, Microfilament Proteins, Neovascularization, Physiologic, Neuropeptides, Nitric Oxide, Phosphoproteins, Signal Transduction, Vascular Endothelial Growth Factor A, rac GTP-Binding Proteins, rac1 GTP-Binding Protein