title: Reversal of endothelial nitric oxide synthase uncoupling and up-regulation of endothelial nitric oxide synthase expression lowers blood pressure in hypertensive rats.
abstract: OBJECTIVE
  We sought to examine the hypothesis that a pharmacologic up-regulation of endothelial nitric oxide synthase (eNOS) combined with a reversal of eNOS uncoupling provides a protective effect against cardiovascular disease.
  
  
  BACKGROUND
  Many cardiovascular diseases are associated with oxidant stress involving protein kinase C (PKC) and uncoupling of eNOS.
  
  
  METHODS
  Messenger ribonucleic acid (mRNA) expression was analyzed with RNase protection assay or quantitative real-time polymerase chain reaction, vascular nitric oxide (NO) with spin trapping, and reactive oxygen species (ROS) with dihydroethidium fluorescence.
  
  
  RESULTS
  Aortas of spontaneously hypertensive rats (SHR) showed an elevated production of ROS when compared with aortas of Wistar-Kyoto rats (WKY). The aortic expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits (Nox1, Nox2, Nox4, and p22phox) was higher in SHR compared with WKY. In SHR, aortic production of ROS was reduced by the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), indicating eNOS "uncoupling" in hypertension. Oral treatment with the PKC inhibitor midostaurin reduced aortic Nox1 expression, diminished ROS production, and reversed eNOS uncoupling in SHR. Aortic levels of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) were significantly reduced in SHR compared with WKY. Midostaurin normalized BH4 levels in SHR. In both WKY and SHR, midostaurin increased aortic expression of eNOS mRNA and protein, stimulated bioactive NO production, and enhanced relaxation of the aorta to acetylcholine. Midostaurin lowered blood pressure in SHR and, to a lesser extent, in WKY; the compound did not change blood pressure in WKY made hypertensive with L-NAME.
  
  
  CONCLUSIONS
  Pharmacologic interventions that combine eNOS up-regulation and reversal of eNOS uncoupling can markedly increase bioactive NO in the vasculature and produce beneficial hemodynamic effects such as a reduction of blood pressure.
authors.affiliation: Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany. HuigeLi@mail.Uni-Mainz.de
authors.forename: Huige
authors.initials: H
authors.lastname: Li
authors.forename: Klaus
authors.initials: K
authors.lastname: Witte
authors.forename: Michael
authors.initials: M
authors.lastname: August
authors.forename: Isolde
authors.initials: I
authors.lastname: Brausch
authors.forename: Ute
authors.initials: U
authors.lastname: Gödtel-Armbrust
authors.forename: Alice
authors.initials: A
authors.lastname: Habermeier
authors.forename: Ellen I
authors.initials: EI
authors.lastname: Closs
authors.forename: Mathias
authors.initials: M
authors.lastname: Oelze
authors.forename: Thomas
authors.initials: T
authors.lastname: Münzel
authors.forename: Ulrich
authors.initials: U
authors.lastname: Förstermann
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006973:Hypertension / Q000201:enzymology* / Q000517:prevention & control*; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism* / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D019311:Staurosporine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015854:Up-Regulation
chemical_list: D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C; D019311:Staurosporine; C059539:midostaurin