Browsing by Author "Rojas-Libano, Daniel"

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    Coordinated Endothelial Nitric Oxide Synthase Activation by Translocation and Phosphorylation Determines Flow-Induced Nitric Oxide Production in Resistance Vessels
    (2013) Figueroa, Xavier F.; Gonzalez, Daniel R.; Puebla, Mariela; Acevedo, Juan P.; Rojas-Libano, Daniel; Duran, Walter N.; Boric, Mauricio P.
    Background/Aims: Endothelial nitric oxide synthase (eNOS) is associated with caveolin-1 (Cav-1) in plasma membrane. We tested the hypothesis that eNOS activation by shear stress in resistance vessels depends on synchronized phosphorylation, dissociation from Cav-1 and translocation of the membrane-bound enzyme to Golgi and cytosol. Methods: In isolated, perfused rat arterial mesenteric beds, we evaluated the effect of changes in flow rate (2-10 ml/min) on nitric oxide (NO) production, eNOS phosphorylation at serine 1177, eNOS subcellular distribution and co-immunoprecipitation with Cav-1, in the presence or absence of extracellular Ca2+. Results: Increases in flow induced a biphasic rise in NO production: a rapid transient phase (3-5-min) that peaked during the first 15 s, followed by a sustained phase, which lasted until the end of stimulation. Concomitantly, flow caused a rapid translocation of eNOS from the microsomal compartment to the cytosol and Golgi, paralleled by an increase in eNOS phosphorylation and a reduction in eNOS-Cav-1 association. Transient NO production, eNOS translocation and dissociation from Cav-1 depended on extracellular Ca2+, while sustained NO production was abolished by the PI3K-Akt blocker wortmannin. Conclusions: In intact resistance vessels, changes in flow induce NO production by transient Ca2+-dependent eNOS translocation from membrane to intracellular compartments and sustained Ca2+-independent PI3K-Akt-mediated phosphorylation. (C) 2013 S. Karger AG, Basel