Inhibition of NOX1 Mitigates Blood Pressure Increases in Elastin Insufficiency

Abstract

Elastin insufficiency leads to the cardiovascular hallmarks of the contiguous gene deletion disorder, Williams-Beuren syndrome, including hypertension and vascular stiffness. Previous studies showed that Williams-Beuren syndrome deletions that extended to include the NCF1 gene were associated with lower blood pressure and reduced vascular stiffness. NCF1 encodes for p47phox, the regulatory component of the NOX1 NADPH oxidase complex, that generates reactive oxygen species in the vascular wall. Dihydroethidium and 8-hydroxyguanosine staining of mouse aortas confirmed that Eln heterozygotes (Eln+/-) had greater reactive oxygen species (ROS) levels than wild types (Eln+/+), a finding that was negated in vessels cultured without hemodynamic stressors. To analyze the Nox effect on elastin insufficiency, we utilized both genetic and chemical manipulations. Both Ncf1 haploinsufficiency (Ncf1+/-) and Nox1 insufficiency (Nox1-/y) decreased oxidative stress and systolic blood pressure in Eln+/- without modifying vascular structure. Chronic treatment with apocynin, a p47phox inhibitor, lowered systolic blood pressure in Eln+/-, but had no impact on Eln+/+ controls. In vivo dosing with phenylephrine produced an augmented blood pressure response in Eln+/- relative to Eln+/+, and genetic modifications or drug-based interventions that lower Nox1 expression reduce the hypercontractile response to phenylephrine in Eln+/- mice to Eln+/+ levels. These results indicate that the mechanical and structural differences caused by elastin insufficiency leading to oscillatory flow can perpetuate oxidative stress conditions which are linked to hypertension, and that by lowering the Nox1-mediated capacity for vascular ROS production, blood pressure differences can be normalized.

Reduced Endothelial Leptin Signaling Increases Vascular Adrenergic Reactivity in a Mouse Model of Congenital Generalized Lipodystrophy

“…Indeed, Nox1 inhibition with the selective Nox1 inhibitor GKT771 [ 15 ] fully restored adrenergic contractility in gBscl2 -/- mice and abolished the difference between gBscl2 +/+ and gBscl2 -/- mice while L-NAME did not. Further evidence in support of a role for Nox1 is provided by additional results from our group and others demonstrating that Nox1 deficiency in mice protects from increases in adrenergic contractility [ 21 , 38 ]. While these data support the role of Nox1, they do not inform on the cell type responsible for the increase in Nox1 activity.…”

Reactive Oxygen Species: Not Omnipresent but Important in Many Locations

“…Both also inhibit Nox-derived ROS production in vitro and in vivo ( Carnesecchi et al, 2009 , 2011 ; Aoyama et al, 2012 ; Green et al, 2012 ; Bettaieb et al, 2015 ; Gorin et al, 2015 ). In sharp contrast to VAS2870 and GKT 137831, the substances apocynin and DPI are still used and falsely addressed as specific Nox inhibitors in many otherwise convincing and excellent studies ( Barbieri et al, 2003 ; Kiritoshi et al, 2003 ; Dostert et al, 2008 ; Choi et al, 2011 ; Abuaita et al, 2015 ; Gatliff et al, 2017 ; Alonso et al, 2019 ; Fan et al, 2019 ; Damiano et al, 2020 ; Geng et al, 2020 ; Inomata et al, 2020 ; Prestes et al, 2020 ; Ahmad et al, 2021 ; Ligeon et al, 2021b ; Martinez et al, 2021 #1039; Troia et al, 2021 ). Several studies have shown that apocynin directly scavenges ROS due to its antioxidant capacities ( Aldieri et al, 2008 ; Heumuller et al, 2008 ; Mora-Pale et al, 2009 ; Wingler et al, 2011 ; Trevelin et al, 2016 ), while DPI inhibits flavoproteins in general ( O’Donnell et al, 1993 ; Wind et al, 2010 ; Altenhofer et al, 2015 ) including Nox2 ( Reis et al, 2020 ), but also various other targets, such as complex I of the mitochondrial electron transport chain ( Bloxham, 1979 ; Lambeth et al, 2008 ; Bulua et al, 2011 ), iNOS ( Stuehr et al, 1991 ; Geyer et al, 1997 ) or xanthine oxidase ( O’Donnell et al, 1993 ; Wind et al, 2010 ) as well as calcium transporters ( Tazzeo et al, 2009 ).…”

Mutation in the matricellular gene fibulin-4 leads to endothelial dysfunction in resistance arteries

“…In the absence of BH4, eNOS is uncoupled and, as a monomer, generates O2rather than NO, further exacerbating oxidative stress 35,37 . It is interesting to note that increased oxidative stress and endothelial dysfunction have been observed in mesenteric and cerebral arteries of elastin insufficient mice (Eln +/-) [46][47][48][49] . Similar to Fbln4 E57K/E57K mice, Eln +/mice exhibit large artery stiffness and systolic hypertension, however, this is due to reduced elastin amount as evidenced by thinning of the elastic lamellae throughout the arterial tree rather than its abnormal assembly or fragmentation 50,51 .…”