title: Adenoviral-mediated overexpression of DDAH improves vascular tone regulation.
abstract: Dimethylarginine dimethylaminohydrolase (DDAH) degrades asymmetric dimethylarginine (ADMA), an endogenously produced nitric oxide (NO) synthase inhibitor. In mammals, two isoforms of DDAH, DDAH1 and DDAH2, are expressed in the cardiovascular system, suggesting that ADMA concentrations are actively regulated in blood vessels, raising the possibility that cardiovascular metabolism of ADMA constitutes a novel mechanism for the regulation of NO production. The purpose of this study was to determine the role of DDAH-catalyzed asymmetric methylarginine metabolism in the regulation of vascular function. We developed adenoviral vectors for the expression of human DDAH1 and 2. Overexpression of DDAH1 or 2 in human umbilical vein endothelial cells (HUVEC) increases DDAH activity, reduces ADMA concentrations and increases NO production. Similarly, overexpression of DDAH1 or 2 in DDAH1(+/-) mice carotid vessels increases NO production and attenuates the response to phenylephrine (PE), enhances acetylcholine (ACh) relaxation and attenuates the effect of exogenously applied ADMA. Finally, overexpression of either DDAH1 or 2 completely reversed the vascular dysfunction seen in DDAH1(+/-) mice. These data indicate that basal concentrations of ADMA in blood vessels are sufficient to regulate NO production, that increases in the level of either DDAH1 or 2, improves vascular function and that overexpression of either DDAH1 or 2 is sufficient to compensate for life-long exposure to elevated ADMA. Thus, therapeutic manipulation of DDAH expression or activity may represent a novel approach to improve vascular dysfunction in various cardiovascular diseases.
authors.affiliation: The British Heart Foundation Laboratories, The Rayne Institute, Division of Medicine, University College London, London, UK. belen.torondel@lshtm.ac.uk
authors.forename: Belen
authors.initials: B
authors.lastname: Torondel
authors.forename: Manasi
authors.initials: M
authors.lastname: Nandi
authors.forename: Peter
authors.initials: P
authors.lastname: Kelly
authors.forename: Beata
authors.initials: B
authors.lastname: Wojciak-Stothard
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fleming
authors.forename: James
authors.initials: J
authors.lastname: Leiper
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000581:Amidohydrolases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism; D002339:Carotid Arteries / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology; D015870:Gene Expression / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009569:Nitric Oxide / Q000378:metabolism; D058729:Peripheral Arterial Disease / Q000503:physiopathology / Q000628:therapy*; D014471:Umbilical Veins / Q000166:cytology; D014661:Vasoconstriction / Q000502:physiology
chemical_list: D049452:Green Fluorescent Proteins; D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D001120:Arginine; D000581:Amidohydrolases; C059999:dimethylargininase