Pressure overload-induced myocardial hypertrophy in mice does not require gp91phox.
BACKGROUND
Reactive oxygen species (ROS) may mediate pressure overload-induced myocardial hypertrophy. NADPH oxidase may be involved in this process, because its expression and activity are upregulated by pressure overload and because myocardial hypertrophy caused by a subpressor infusion of angiotensin is attenuated in mice deficient in the gp91phox catalytic subunit of NADPH oxidase.


RESULTS
To test the role of NADPH oxidase-dependent ROS in mediating pressure overload-induced myocardial hypertrophy, we subjected transgenic mice lacking gp91phox to chronic pressure overload caused by constriction of the ascending aorta. Contrary to our hypothesis, neither myocardial hypertrophy nor NADPH-dependent superoxide generation was decreased in gp91phox-deficient mice after aortic constriction. Aortic constriction caused an exaggerated increase in p22phox and p47phox mRNA in gp91phox-deficient mice.


CONCLUSIONS
These results indicate that gp91phox is not necessary for pressure overload-induced hypertrophy in the mouse and suggest the involvement of another source of ROS, possibly an NADPH oxidase that does not require the gp91phox subunit.
Maytin
Melanie
M
Department of Medicine, Cardiovascular Section, Boston University Medical Center, and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass 02118, USA.
Siwik
Deborah A
DA
Ito
Masahiro
M
Xiao
Lei
L
Sawyer
Douglas B
DB
Liao
Ronglih
R
Colucci
Wilson S
WS
D000818:Animals; D001011:Aorta; D006332:Cardiomegaly / Q000175:diagnosis / Q000201:enzymology* / Q000209:etiology; D003250:Constriction; D005978:Glutathione / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D019255:NADPH Oxidases / Q000235:genetics / Q000502:physiology*; D011312:Pressure; D021122:Protein Subunits / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism
D021122:Protein Subunits; D012333:RNA, Messenger; D019255:NADPH Oxidases; D005978:Glutathione