Nox1 overexpression potentiates angiotensin II-induced hypertension and vascular smooth muscle hypertrophy in transgenic mice.
BACKGROUND
Reactive oxygen species (ROS) have been implicated in the development of cardiovascular pathologies. NAD(P)H oxidases (Noxes) are major sources of reactive oxygen species in the vessel wall, but the importance of individual Nox homologues in specific layers of the vascular wall is unclear. Nox1 upregulation has been implicated in cardiovascular pathologies such as hypertension and restenosis.


RESULTS
To investigate the pathological role of Nox1 upregulation in vascular smooth muscle, transgenic mice overexpressing Nox1 in smooth muscle cells (TgSMCnox1) were created, and the impact of Nox1 upregulation on the medial hypertrophic response during angiotensin II (Ang II)-induced hypertension was studied. These mice have increased expression of Nox1 protein in the vasculature, which is accompanied by increased superoxide production. Infusion of Ang II (0.7 mg/kg per day) into these mice for 2 weeks led to a potentiation of superoxide production compared with similarly treated negative littermate controls. Systolic blood pressure and aortic hypertrophy were also markedly greater in TgSMCnox1 mice than in their littermate controls. To confirm that this potentiation of vascular hypertrophy and hypertension was due to increased ROS formation, additional groups of mice were coinfused with the antioxidant Tempol. Tempol decreased the level of Ang II-induced aortic superoxide production and partially reversed the hypertrophic and hypertensive responses in these animals.


CONCLUSIONS
These data indicate that smooth muscle-specific Nox1 overexpression augments the oxidative, pressor, and hypertrophic responses to Ang II, supporting the concept that medial Nox1 participates in the development of cardiovascular pathologies.
Dikalova
Anna
A
Division of Cardiology, Emory University, Atlanta, GA 30322, USA.
Clempus
Roza
R
Lassègue
Bernard
B
Cheng
Guangjie
G
McCoy
James
J
Dikalov
Sergey
S
San Martin
Alejandra
A
Lyle
Alicia
A
Weber
David S
DS
Weiss
Daiana
D
Taylor
W Robert
WR
Schmidt
Harald H H W
HH
Owens
Gary K
GK
Lambeth
J David
JD
Griendling
Kathy K
KK
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D006973:Hypertension / Q000235:genetics / Q000503:physiopathology*; D006984:Hypertrophy; D051379:Mice; D008822:Mice, Transgenic; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases / Q000235:genetics*
D000804:Angiotensin II; D049452:Green Fluorescent Proteins; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; C402799:NOX1 protein, human