title: NADPH oxidase accounts for enhanced superoxide production and impaired endothelium-dependent smooth muscle relaxation in BKbeta1-/- mice.
abstract: OBJECTIVE
  Nitric oxide (NO)-induced vasorelaxation involves activation of large conductance Ca2+-activated K+ channels (BK). A regulatory BKbeta1 subunit confers Ca2+, voltage, and NO/cGMP sensitivity to the BK channel. We investigated whether endothelial function and NO/cGMP signaling is affected by a deletion of the beta1-subunit.
  
  
  RESULTS
  Vascular superoxide in BKbeta1-/- was measured using the fluorescent dye hydroethidine and lucigenin-enhanced chemiluminescence. Vascular NO formation was analyzed using electron paramagnetic resonance (EPR), expression of NADPH oxidase subunits, the endothelial NO synthase (eNOS), the soluble guanylyl cyclase (sGC), as well as the activity and expression of the cyclic GMP-dependent kinase I (cGK-I) were assessed by Western blotting technique. eNOS, sGC, cGK-I expression and acetylcholine-induced NO production were unaltered in Bkbeta1-/- animals, whereas endothelial function was impaired and the activity of the cGK-I was reduced. Vascular O2- and expression of the NADPH oxidase subunits p67phox and Nox1 were increased. Endothelial dysfunction was normalized by the NADPH oxidase inhibitor apocynin. Potassium chloride- and iberiotoxin-induced depolarization mimicked the effect of BKbeta1-deletion by increasing vascular O2- in an NADPH-dependent fashion.
  
  
  CONCLUSIONS
  The deletion of BKbeta1 causes endothelial dysfunction by increasing O2- formation via increasing activity and expression of the vascular NADPH oxidase.
authors.affiliation: II.Medizinische Klinik, Johannes Gutenberg-Universität Mainz, Langenbeckstrasse 1, D-55131 Mainz, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Oelze
authors.forename: Ascan
authors.initials: A
authors.lastname: Warnholtz
authors.forename: Jörg
authors.initials: J
authors.lastname: Faulhaber
authors.forename: Philip
authors.initials: P
authors.lastname: Wenzel
authors.forename: Andrei L
authors.initials: AL
authors.lastname: Kleschyov
authors.forename: Meike
authors.initials: M
authors.lastname: Coldewey
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hink
authors.forename: Olaf
authors.initials: O
authors.lastname: Pongs
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fleming
authors.forename: Sven
authors.initials: S
authors.lastname: Wassmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Meinertz
authors.forename: Heimo
authors.initials: H
authors.lastname: Ehmke
authors.forename: Andreas
authors.initials: A
authors.lastname: Daiber
authors.forename: Thomas
authors.initials: T
authors.lastname: Münzel
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology; D015815:Cell Adhesion Molecules / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D004730:Endothelium, Vascular / Q000503:physiopathology*; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000172:deficiency*; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D020033:Protein Isoforms / Q000172:deficiency; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism*; D014664:Vasodilation; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008840:Microfilament Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; C079789:neutrophil cytosol factor 67K; D000098662:Vasodilator-Stimulated Phosphoprotein; D013481:Superoxides; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; C000614711:NOX1 protein, mouse; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase