Specific Nox-2 inhibition decreases oxidatieve stress and impairs vascular smooth muscle cell proliferation

MARTINEZ PEREIRA, J; REDONDO,A; QUESADA, I; CIFUENTES, MARIA EUGENIA; PAGANO, PATRICK; CASTRO C

Atenas

Congreso; Joint Meeting ESH-ISH Hypertension; 2014

European Society of Hypertension

Oxidative stress has been discussed as a key mechanism of endothelial dysfunction and cardiovascular disease. Reactive Oxygen Species (ROS) not only alter vascular contractility but also influence vascular remodeling, another phenomenon associated with hypertension. NADPH oxidase (Nox) is present in the vascular wall as a precursor and initiator of inflammation and remodeling suggesting a direct and/or paracrine role in vascular dysfunction We proposed to examine the molecular mechanisms of Nox-2 subunit inactivation, using an inhibitor peptide Nox2ds-tat designed to specifically inhibit interactions between Nox2 oxidase and p47phox, in vascular smooth muscle cells (VSMC) obtained from mesenteric resistance arteries of spontaneously hypertensive rats (SHR). VSMC were incubated with 50 mM Nox2ds-tat, a competitive peptide antagonist of p47phox-Nox2 interaction that suppresses the induction of O-2 by Angiotensin II (AII). Cells were treated with Nox2ds-tat or scrambled 1 hour prior 4 hours treatment with AII (10-7 M). Nox subunits expression was evaluated by real time-PCR, ROS production was evaluated by incubation with a fluorescent probe (H2DCF-DA), Nox activity by chemiluminescence with lucigenin and cell proliferation by colorimetric assays (MTT). Data were analyzed by ANOVA and Bonferroni?s post test We first found that Nox2 and p47phox, Nox complex subunits, were up-regulated in mesenteric VSMC from SHR compared with VSMC from normotensive rats. After the treatment with AII mesenteric VSMC showed an increase in ROS production inhibited by Nox2ds-tat. The NADPH oxidase activity stimulated by AII was decreased by Nox2ds-tat. The peptide also significantly inhibited AII-induced proliferation of mesenteric smooth muscle cells from genetically hypertensive rats. Our results suggest that the inhibitory peptide Nox2 has a potent effect on vascular dysfunction. It is attractive to speculate that small molecule specific selective inhibitors for different Noxs could exert a beneficial effect on vascular pathology.