Submitted January 17, 2007
Accepted June 21, 2007
Functional interplay between endothelial nitric oxide
synthase and membrane type 1-matrix metalloproteinase in
migrating endothelial cells
Laura Genis, Pilar Gonzalo, Antonio S Tutor, Beatriz G Galvez, Antonio Martinez-Ruiz, Carlos Zaragoza, Santiago Lamas, Karl Tryggvason, Suneel S Apte, and Alicia G Arroyo*
Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
Atherothrombosis and Cardiovascular Imaging, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
Cellular and Molecular Pathophysiology, Centro de Investigaciones Biologicas, Instituto "Reina Sofia" de Investigaciones Nefrologicas (CSIC), Madrid, Spain
Matrix Biology and Biochemistry, Karolinska Institute, Stockholm, Sweden
Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
* Corresponding author; email: agarroyo{at}cnic.es.
Nitric oxide (NO) is essential for vascular homeostasis and is also a critical modulator of angiogenesis; however, the molecular mechanisms of NO action during angiogenesis remain elusive. We have investigated the potential relationship between NO and membrane type 1-matrix metalloproteinase (MT1-MMP) during endothelial migration and capillary tube formation. Endothelial NO synthase (eNOS) colocalizes with MT1-MMP at motility-associated structures in migratory human endothelial cells (ECs); moreover, NO is produced at these structures and is released into the medium during EC migration. We have therefore addressed two questions: 1) the putative regulation of MT1-MMP by NO in migratory ECs; and 2) the requirement for MT1-MMP in NO-induced EC migration and tube formation. NO upregulates MT1-MMP membrane clustering on migratory human ECs, and this is accompanied by increased degradation of type I collagen substrate. MT1-MMP membrane expression and localization are impaired in lung ECs from eNOS-deficient mice, and these cells also show impaired migration and tube formation in vitro. Inhibition of MT1-MMP with a neutralizing antibody impairs NO-induced tube formation by human ECs, and NO-induced endothelial migration and tube formation are impaired in lung ECs from mice deficient in MT1-MMP. MT1-MMP thus appears to be a key molecular effector of NO during EC migration and angiogenic processes, and is a potential therapeutic target for NO-associated vascular disorders.
