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Cadmium, a ubiquitous heavy metal, interferes with endothelial functions and angiogenesis. Bradykinin is a Ca-mobilizing soluble peptide that acts via nitric oxide to promote vasodilation and capillary permeability. The objective of the present study was to explore the Cd implications in bradykinin-dependent endothelial functions. An egg yolk angiogenesis mod el was employed to evaluate the effect of Cd on bradykinin-induced angiogenesis. The results demonstrate that 100 nmol/L Cd attenuated bradykinin-dependent angiogenesis. The results of the in vitro wound healing and tube formation assays by using EAhy 92 6, a transformed endothelial cell line, suggest that Cd blocked bradykinin-mediated endothelial migration and tube formation by 38% and 67%, respectively, while nitric oxide supplementation could reverse the effect of Cd on bradykinin-induced endothelial migration by 94%. The detection of nitric oxide by using a DAF- 2DA fluorescent probe, Griess assay, and ultrasensitive electrode suggests that Cd blocked bradykinin-induced nitric oxide production. Fluorescence imaging of eNOS-GFP transfected endothelial cells, immunofluroscence, and Western blot studies of Cd and b radykinin-treated cells show that Cd interfered with the localization pattern of eNOS, which possibly attenuates nitric oxide production in part. Additionally, Ca imaging of Cd- and bradykinin-treated cells suggests that Cd blocked bradykinin-dependent C a influx into the cells, thus partially blocking Ca-dependent nitric oxide production in endothelial cells. The results of this study conclude that Cd blunted the effect of bradykinin by interfering with the Ca-associated NOS activity specifically by imp eding subcellular trafficking of eNOS. Key words: cadmium chloride, endothelial cells, angiogenesis, nitric oxide, endothelial nitric oxide synthase. Resume: Le Cd, un metal lourd ubiquiste, interfere avec les fonctions endotheliales et l'angiogenese. La bradykinine est un peptide soluble mobilisateur de Ca qui agit par l'intermediaire de l'oxyde nitrique pour promouvoir la vasodilatation et la permeabilite capillaire. L'objectif de cette etude etait d'explorer l'implication du Cd dans les fonctions endotheliales dependantes de la bradykinine. Le modele d'angiogenese vitelline a ete utilise pour evaluer l'effet du Cd sur l' angiogenese induite par la bradykinine. Les resultats demontrent qu'une concentration de 100 nmol/L Cd a diminue l'angiogenese ddependant de la bradykinine. Les resultats obtenus d'experiences de cicatrisation et de formation de vaisseaux in vitro realis ees avec les cellules EAhy 926, une lignee endotheliale transformee, suggerent que le Cd a bloque la migration endotheliale et la formation de vaisseaux induites par la bradykinine de 38 % et 67 % respectivement, alors qu'un apport en oxyde nitrique pouv ait renverser les effets du Cd sur la migration des cellules endotheliales induite par la bradykinine de 94%. La detection de l'oxyde nitrique a l'aide de la sonde fluorescente DAF-2DA, de l'essai de Griess et d'une electrode ultra- sensible suggerent que le Cd a bloque la production d'oxyde nitrique induite par la bradykinine. L'imagerie en fluorescence de cellules endotheliales transfectees avec la eNOS-GFP ainsi que des etudes d'immunofluorescence et d'immunobuvardage de cellules traitees au Cd et a la bradykinine montrent que le Cd a modifie le patron de localisation de l'eNOS, ce qui, en partie, attenue possiblement la production d'oxyde nitrique. De plus, l'imagerie du Ca des cellules traitees au Cd et a la bradykinine suggere que le Cd a bloque l'influx calcique dependant de la bradykinine dans la cellule, bloquant ainsi partiellement la production d'oxyde nitrique dependante du Ca dans les cellules endotheliales. Les resultats de ce tte etude permettent de conclure que le Cd a perturbe l'effet de la bradykinine en interferant avec l'activite de l'oxyde nitrique synthase associee au Ca et empechant specifiquement le trafic subcellulaire de l'eNOS. Mots-cles : chlorure de cadmium, cellules endotheliales, angiogenese, oxyde nitrique, oxyde nitrique synthase endotheliale. [Traduit par la Redaction], Introduction Cadmium is a widely distributed industrial and environmental pollutant that currently ranks eighth on the Agency for Toxic Substances and Disease Registry (ATSDR) Priority List of Hazardous Substances (ATSDR [...]

Abstract: Cadmium (Cd) perturbs vascular health and interferes with endothelial function. However, the effects of exposing endothelial cells to low doses of Cd on the production of nitric oxide (NO) [...]

Abstract: Hepatic stellate cells are liver-specific pericytes and exist in close proximity with endothelial cells. The activation of liver pericytes is intrinsic to liver pathogenesis, and leads to endothelial dysfunction, [...]

Hypoxia induces barrier dysfunctions in endothelial cells. Nitric oxide is an autacoid signallingmolecule that confers protection against hypoxia-mediated barrier dysfunctions. Dyn-2 (dynamin-2), a large GTPase and a positive modulator of eNOS (endothelial nitric oxide synthase), plays an important role in maintaining vascular homeostasis. The present study aims to elucidate the role of dyn-2 in hypoxia-mediated leakiness of the endothelial monolayer in relation to redox milieu. Inhibition of dyn-2 by transfecting the cells with K44A, a dominant negative construct of dyn-2, elevated leakiness of the endothelial monolayer under hypoxia. Sodium nitroprusside (nitric oxide donor) and uric acid (peroxynitrite quencher) were used to evaluate the role of nitric oxide and peroxynitrite in maintaining endothelial barrier functions under hypoxia. Administration of nitric oxide and uric acid recovered hypoxia-mediated leakiness of K44A-overexpressed endothelial monolayer. Our study confirms that inhibition of dyn-2 induces leakiness in the endothelial monolayer by increasing the load of peroxynitrite under hypoxia. [ABSTRACT FROM AUTHOR]