title: Moderate caveolin-1 downregulation prevents NADPH oxidase-dependent endothelial nitric oxide synthase uncoupling by angiotensin II in endothelial cells.
abstract: OBJECTIVE
  We analyzed the role of caveolin-1 (Cav-1) in the cross-talk between NADPH oxidase and endothelial nitric oxide synthase (eNOS) signaling in endothelial caveolae.
  
  
  RESULTS
  In intact endothelial cells, angiotensin II (AII) concurrently increased NO and O(2)(-·) production (to 158±12% and 209±5% of control). NO production was sensitive to inhibition of NADPH oxidase and small interfering RNA downregulation of nonreceptor tyrosine kinase cAbl. Reciprocally, N-nitro-l-arginine methyl ester, a NOS inhibitor, partly inhibited O(2)(-·) stimulated by AII (by 47±11%), indicating eNOS uncoupling, as confirmed by increased eNOS monomer/dimer ratio (by 35%). In endothelial cell fractions separated by isopycnic ultracentrifugation, AII promoted colocalization of cAbl and the NADPH oxidase subunit p47phox with eNOS to Cav-1-enriched fractions, as confirmed by proximity ligation assay. Downregulation of Cav-1 by small interfering RNA (to 50%), although it preserved eNOS confinement, inhibited AII-stimulated p47phox translocation and NADPH oxidase activity in Cav-1-enriched fractions and reversed eNOS uncoupling. AII infusion produced hypertension and decreased blood hemoglobin-NO in Cav-1(+/+) mice but not in heterozygote Cav-1(+/-) mice with similar Cav-1 reduction.
  
  
  CONCLUSIONS
  Cav-1 critically regulates reactive oxygen species-dependent eNOS activation but also eNOS uncoupling in response to AII, underlining the possibility to treat endothelial dysfunction by modulating Cav-1 abundance.
authors.affiliation: Pole of Pharmacology and Therapeutics (FATH 5349), Institute of Clinical and Experimental Research, Université catholique de Louvain, Brussels, Belgium. irina.lobysheva@uclouvain.be
authors.forename: Irina
authors.initials: I
authors.lastname: Lobysheva
authors.forename: Géraldine
authors.initials: G
authors.lastname: Rath
authors.forename: Belaïd
authors.initials: B
authors.lastname: Sekkali
authors.forename: Caroline
authors.initials: C
authors.lastname: Bouzin
authors.forename: Olivier
authors.initials: O
authors.lastname: Feron
authors.forename: Bernard
authors.initials: B
authors.lastname: Gallez
authors.forename: Chantal
authors.initials: C
authors.lastname: Dessy
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Balligand
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D051242:Caveolin 1 / Q000502:physiology*; D002478:Cells, Cultured; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000517:prevention & control; D008297:Male; D051379:Mice; D019255:NADPH Oxidases / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III / Q000502:physiology*; D016315:Proto-Oncogene Proteins c-abl / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D051242:Caveolin 1; D006454:Hemoglobins; D017382:Reactive Oxygen Species; D013481:Superoxides; D000804:Angiotensin II; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019255:NADPH Oxidases; D016315:Proto-Oncogene Proteins c-abl