Molecular mechanisms of hypertension: role of Nox family NADPH oxidases.
OBJECTIVE
Molecular mechanisms contributing to the pathoetiology of hypertension are complex, involving many interacting systems such as signaling through G protein-coupled receptors, the renin-angiotensin system, vascular inflammation and remodeling, vascular senescence and aging and developmental programming, as highlighted in the current issue of the journal. Common to these systems is NADPH oxidase-derived reactive oxygen species (ROS). This editorial highlights current concepts relating to the production of ROS in hypertension and focuses on the Nox family NADPH oxidases, major sources of free radicals in the cardiovascular and renal systems.


RESULTS
ROS play a major role as intracellular signaling molecules to regulate normal biological cellular responses. In pathological conditions, loss of redox homeostasis contributes to vascular oxidative damage. Recent evidence indicates that specific enzymes, the Nox family of NADPH oxidases, have the sole function of generating ROS in a highly regulated fashion in physiological conditions, and that in disease states, hyperactivation of Noxes contributes to oxidative stress and consequent cardiovascular and renal injury. The Nox family comprises seven members, Nox1-Nox7. Nox1, Nox2 (gp91phox-containing NADPH oxidase), Nox4 and Nox5 have been identified in the cardiovascular-renal systems and have been implicated in the pathophysiology of cardiovascular and renal disease.


CONCLUSIONS
Noxes, which are differentially regulated in hypertension, are major sources of cardiovascular and renal oxidative stress. This has evoked considerable interest because of the possibilities that therapies targeted against specific Nox isoforms to decrease ROS generation or to increase nitric oxide availability or both may be useful in minimizing vascular injury and renal dysfunction, and thereby prevent or regress target organ damage associated with hypertension.
Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ontario, Canada.
Mona
M
Sedeek
Richard L
RL
Hébert
Chris R
CR
Kennedy
Kevin D
KD
Burns
Rhian M
RM
Touyz
D000818:Animals; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D008562:Membrane Glycoproteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D000074624:NADPH Oxidase 1; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism
D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D017382:Reactive Oxygen Species; C056558:CYBB protein, human; D000074624:NADPH Oxidase 1; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases; C402799:NOX1 protein, human; C498910:NOX4 protein, human; C431571:NOX5 protein, human