Novel Competitive Inhibitor of NAD(P)H Oxidase Assembly Attenuates Vascular O ₂ ⁻ and Systolic Blood Pressure in Mice

Abstract

Abstract-We previously reported enhanced expression of the p67 phox and gp91 phox components of NAD(P)H oxidase in angiotensin (Ang) II-induced hypertension, suggesting de novo assembly in response to Ang II. To examine the direct involvement of NAD(P)H oxidases in Ang II-induced O 2 Ϫ production, we designed a chimeric peptide that inhibits p47 phox association with gp91 phox in NAD(P)H oxidase (gp91ds-tat). This was achieved by linking a 9-amino acid peptide (aa) derived from HIV-coat protein (tat) to a 9-aa sequence of gp91 phox (known to interact with p47 phox ). As a control, we constructed a chimera containing tat and a scrambled gp91 sequence (scramb-tat). We found that gp91ds-tat decreased O 2 Ϫ levels in aortic rings treated with Ang II (10 pmol/L) but had no effect on either the O 2 Ϫ -generating enzyme xanthine oxidase or potassium superoxide-generated O 2 Ϫ . We infused vehicle, Ang II (0.75 mg · kg, or Ang IIϩscramb-tat intraperitoneally in C57Bl/6 mice and measured systolic blood pressure (SBP) on days 0, 3, 5, and 7 of infusion. SBP increased by day 3 in mice given Ang II and Ang IIϩscramb-tat but was significantly lower with Ang IIϩgp91-tat. On day 7, SBP was still significantly inhibited in mice given Ang IIϩgp91ds-tat, whereas Ang II-induced O 2 Ϫ production was inhibited throughout the aorta as detected by dihydroethidium staining, consistent with the ability of this inhibitor to block the various vascular NAD(P)H oxidase isoforms. These data support the hypothesis that inhibition of the interaction of p47 phox and gp91 phox (or its homologues) can block O 2 Ϫ production and attenuate blood pressure elevation in mice.

The effect of p22phox −930A/G, A640G and C242T polymorphisms of NADPH oxidase on peripheral and central pressures in healthy, normotensive individuals

“…24 The advent of NADPH oxidase inhibitors breaks new ground pertaining to potential clinical applications. Apocynin 26 , gp91ds-tat 27 and protein kinase C inhibitors 28 have been shown to decrease blood pressure; nevertheless, they have not been implemented in clinical practice. 15 Dihydropyridines 29 and blockade of the reninangiotensin-aldosterone axis by means of angiotensin-converting inhibitors 30 or angiotensin receptor blockers 31 have been shown to effectively inhibit NADPH activation and concomitant production of ROS.…”

Nox2-Derived Reactive Oxygen Species Mediate Neurovascular Dysregulation in the Aging Mouse Brain

“…In these experiments, we used the NADPH oxidase peptide inhibitor gp91ds-tat (Kazama et al, 2004;Park et al, 2005;Rey et al, 2001) to establish whether the age-related alterations in neurovascular function are mediated by NADPH oxidase. In 3-month-old mice, neocortical application of gp91ds-tat (1 mmol/ L; n = 5/group) or its scrambled control (1 mmol/L; n = 5/group) did not alter resting CBF or the cerebrovascular responses studied ( Figures 4A to 4H).…”

Tat-NR2B9c Prevents Excitotoxic Neuronal Superoxide Production

“…This effect was comparable to that achieved with the gp91ds-Tat peptide ( Figures 1B and 1C), which prevents assembly of the active neuronal NOX2 complex. 10,12 By contrast, the nNOS inhibitor L-N G -nitroarginine methyl ester (L-NAME) had no effect on superoxide production. The inhibitory effect of Tat-NR2B9c on NMDA-induced superoxide production was further confirmed by imaging formation of the lipid peroxidation product, 4-hydroxynonenal ( Figures 1D and 1E).…”