Abstract 057: Nox5 Induces Vascular Dysfunction and Arterial Remodelling Independently of Blood Pressure Elevation in Ang II-infused Nox5-expressing Mice

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Augusto C Montezano ◽  
Adam P Harvey ◽  
Francisco J Rios ◽  
Maria Dulak-Lis ◽  
Wendy Beatie ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Function ◽  
Kinase Inhibitor ◽  
Vascular Dysfunction ◽  
Rho Kinase ◽  
Lumen Diameter ◽  
Ang Ii ◽  
Cross Sectional ◽  
Blood Pressure Elevation ◽  
Endothelium Dependent Relaxation

Nox5 is a unique Ca 2+ -sensitive Nox isoform that is expressed in human vascular smooth muscle cells (VSMC). Although Nox5 has been implicated in diabetic nephropathy, its role in vascular function and development of hypertension remain unclear. Nox5 is not expressed in rodents, and accordingly we generated humanised Nox5 mice with Nox5 expressed in a VSMC-specific manner (Nox5SM22). Control (wild-type) and Nox5SM22 mice were infused with Ang II (600 ng/Kg/day). Blood pressure (BP) was assessed by tail-cuff. Vascular function and structure of resistance arteries were measured by myography. Ang II increased BP in WT (182.5±10 mmHg) and Nox5SM22 mice (173.1±5 mmHg) with no significant differences. Arteries from Nox5SM22 mice exhibited reduced endothelium-dependent relaxation versus WT controls (%ACh relaxation: 55.1±4 vs ctl: 81.6±7%). Fasudil (Rho kinase inhibitor)-induced relaxation was reduced in Nox5SM22 mice versus controls (%Fas: 111.3±11 vs ctl: 166.6±8%) (p<0.05). Ang II increased the maximal contraction to U46619 (thromboxane A2 mimetic) in WT (115.8±2 vs untreated: 101.4±2%) and Nox5SM22 (121.3±3 vs untreated: 99.1±2) (p<0.05) and induced endothelial dysfunction in all groups. Fasudil-induced relaxation was impaired by Ang II in WT (102.7±6 vs untreated: 166.6±8%, p<0.05) but not further impaired in Nox5SM22 mice (114.9±6 vs untreated: 111.3±11%). Ang II increased cross-sectional area (CSA) and lumen diameter; while in Nox5SM22 mice, Ang II increased wall thickness, wall-to-lumen ratio, CSA and decreased lumen diameter, with associated increased vascular stiffness. Our findings indicate that in mice expressing human Nox5 in VSMCs, endothelium-dependent relaxation is impaired, fasudil-mediated vasodilation is attenuated and vessels undergo exaggerated hypertrophic inward remodelling with increased stiffness; processes that occur independently of BP elevation. These data suggest an important role for Nox5 in Ang II-induced vascular dysfunction and remodeling, but not in the development of hypertension. Moreover, we identify Rho kinase as a putative target for Nox5-induced vascular injury. We provide novel insights into Nox5 vascular biology and demonstrate that vascular Nox5 actions are dissociated from BP effects.

Endothelial dysfunction and hypercontractility of vascular myocytes are ameliorated by fluvastatin in obese Zucker rats

2005 ◽  
Vol 288 (4) ◽  
pp. H1770-H1776 ◽  
Author(s):  
Hiroaki Nishimatsu ◽  
Etsu Suzuki ◽  
Hiroshi Satonaka ◽  
Ryo Takeda ◽  
Masao Omata ◽  
...  
Keyword(s):  
Relative Intensity ◽  
Vascular Function ◽  
Kinase Inhibitor ◽  
Vascular Dysfunction ◽  
Rho Kinase ◽  
Zucker Rats ◽  
Ang Ii ◽  
Enos Expression ◽  
Akt Phosphorylation ◽  
Dependent Pathway

To study the mechanisms of vascular dysfunction in diabetes mellitus, we examined the responses of the aorta to adrenomedullin (AM) and ANG II in obese Zucker (OZ), lean Zucker (LZ), and OZ rats administered fluvastatin (OZ + Flu). AM-induced endothelium-dependent vasorelaxation was impaired in OZ rats compared with LZ rats, and fluvastatin restored AM-induced, endothelium-dependent vasorelaxation (%Δtension at 10−7 mol/l AM; LZ, −85.1 ± 3.1%; OZ, −50.7 ± 2.5%; OZ + Flu, −75.6 ± 2.7%). Expression of endothelial nitric oxide synthase (eNOS) and Akt phosphorylation in response to AM (10−7 mol/l) were also diminished in OZ rats. Fluvastatin restored the eNOS expression and Akt phosphorylation [eNOS expression (relative intensity): LZ, 2.3 ± 0.4; OZ, 1.0 ± 0.2; OZ + Flu, 1.8 ± 0.3; Akt phosphorylation (relative intensity): LZ, 2.3 ± 0.2; OZ, 1.0 ± 0.3; OZ + Flu, 1.9 ± 0.2]. ANG II-induced vasoconstriction was enhanced in the aortic rings of OZ rats compared with LZ rats, and this enhanced vasoconstriction was partially normalized by fluvastatin and was abolished when the aorta of OZ rats was preincubated with the Rho kinase inhibitor Y-27632. GTPγS-induced contraction of permeabilized aortic smooth muscle cells, which is an indicator of the Rho-dependent Ca2+ sensitization of contraction, was enhanced in OZ rats compared with LZ rats, and this enhanced contraction was suppressed in OZ + Flu rats. These results suggested that endothelium-dependent vasorelaxation was impaired, Ca2+ sensitization of contraction was augmented in blood vessels of OZ rats and that fluvastatin restored vascular function by activating the Akt-dependent pathway and inhibiting the Rho-dependent pathway.

Abstract P006: Liraglutide Attenuates Cardiac Fibrosis and Vascular Dysfunction in a Non-diabetic Angiotensin II-infusion Model via Anti-inflammatory and Anti-oxidant Mechanisms

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Huey Wen Lee ◽  
Melita Brdar ◽  
Robert Widdop ◽  
Anthony Dear ◽  
Tracey Gaspari
Keyword(s):  
Blood Pressure ◽  
Vascular Function ◽  
Cardiac Fibrosis ◽  
Vascular Dysfunction ◽  
Cardiomyocyte Hypertrophy ◽  
High Dose ◽  
Protective Effects ◽  
Ang Ii ◽  
Treatment Protocols ◽  
Glucose Levels

Glucagon-like peptide-1 (GLP-1) based therapies are used to treat type II diabetes via increasing insulin secretion and inhibiting glucagon production. Recent evidence suggests that activating the GLP-1 receptor may also mediate direct vaso-protective effects. Therefore the objective of the study was to determine whether GLP-1R stimulation conferred cardio- and vaso-protection in a non-diabetic setting using the angiotensin (Ang) II infusion model of hypertension and cardiovascular dysfunction. Male C57Bl/6J mice (4-6 months) were assigned to one of the following 4 week treatment protocols: 1) vehicle (saline), 2) Ang II (800ng/kg/day), 3) Ang II + liraglutide (30μg/kg/day), 4) Ang II + liraglutide (300μg/kg/day). All treatments were administered via osmotic mini-pumps (s.c). After 4 weeks the effect of liraglutide treatment on blood pressure, vascular function and cardiac remodelling was examined. Liraglutide (both doses) attenuated Ang II-induced increase in systolic blood pressure (Ang II: 175.3 ± 8.6mmHg vs Ang II+Lirag (30) 150.2 ± 6.4 mmHg or Ang II+Lirag (300): 145.4 ± 6.9 mmHg) without affecting blood glucose levels. Liraglutide (both doses) completely prevented Ang II-induced endothelial dysfunction (% maximum relaxation: Ang II=50.7 ± 7.8%; Ang II+Lirag (30)=82.7 ± 5.8; Ang II+Lirag (300)=81.5 ± 6.1%). In the heart, liraglutide prevented Ang II-induced cardiomyocyte hypertrophy (n=7-10; p<0.05) and reduced collagen deposition (% collagen expression: Ang II=4.4 ± 0.5 vs Ang II+Lirag(300)=2.9 ± 0.3; n=7-9; p<0.01). This anti-fibrotic effect was attributed to reduced fibroblast/myofibroblast expression as well as decreased inflammation with reduced NFκB and MCP-1 expression and decreased oxidative stress with a significant reduction in superoxide production using high dose of liraglutide. Overall, stimulation of GLP-1R in a non-diabetic setting protected against Ang II-mediated cardiac hypertrophy, cardiac fibrosis and vascular dysfunction, indicating potential for use of GLP-1 based therapies in treatment of cardiovascular disease independent of diabetes.

scholarly journals The absence of sympathoexcitation during the development of hypertension in Cyp1a1 Ren-2 transgenic rats

2019 ◽  
pp. 329-334
Author(s):  
J. Zicha ◽  
J. Hojná ◽  
L. Kopkan ◽  
L. Červenka ◽  
I. Vaněčková
Keyword(s):  
Blood Pressure ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Renin Angiotensin System ◽  
Ang Ii ◽  
Transgenic Rats ◽  
Calcium Sensitization ◽  
Sympathetic Vasoconstriction ◽  
Rho Kinase Inhibitor ◽  
Dependent Form

The insertion of mouse renin gene (Ren-2) into the genome of normotensive rats causes a spontaneous rise of blood pressure (BP), leading to an angiotensin II (Ang II)-dependent form of hypertension in transgenic (mRen-2)27 rats (TGR). However, enhanced sympathetic BP component was demonstrated in heterozygous TGR aged 20 weeks. In the present study we used another model, i.e. Cyp1a1-Ren-2 transgenic rats (iTGR) in which hypertension can be induced by natural xenobiotic indole-3 carbinol (I3C) added to the diet. We investigated whether the development of high blood pressure (BP) in 5-month-old iTGR animals fed I3C diet for 10 days is solely due to enhanced Ang II-dependent vasoconstriction or whether enhanced sympathetic vasoconstriction also participates in BP maintenance in this form of hypertension. Using acute sequential blockade of renin-angiotensin system (RAS), sympathetic nervous system (SNS) and NO synthase (NOS) we have demonstrated that the observed gradual increase of BP in iTGR fed I3C diet was entirely due to the augmentation of Ang II-dependent BP component without significant changes of sympathetic BP component. Thus, the hypertension in iTGR resembles to that of homozygous TGR in which high BP was entirely dependent on Ang II-dependent vasoconstriction. Moreover, our measurements of acute BP response to Rho kinase inhibitor fasudil in animals subjected to a combined blockade of RAS, SNS and NOS indicated the attenuation of basal calcium sensitization in both iTGR and homozygous TGR.

Abstract P127: Angiotensin II Priming Enhances Prostaglandin E2 Vasoconstrictor Effects

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Maria P Kraemer ◽  
Fred Lamb ◽  
Richard M Breyer
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Area Under The Curve ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Ang Ii ◽  
Concentration Dependent Manner ◽  
Femoral Arteries

Prostaglandins are key modulators of blood pressure and arterial tone. Prostaglandin E 2 (PGE 2 ), is a prostanoid that has vasodepressor effects; however, under certain circumstances PGE 2 can induce vasopressor responses. Recent reports demonstrated that sub-threshold concentrations of vasoconstrictors augment PGE 2 -mediated constriction in rat femoral arteries. However, whether angiotensin II (Ang II) could affect PGE 2 -mediated contraction is not known. Using a wire myograph, we demonstrated that PGE 2 had no significant effect on mouse femoral arterial rings at doses up to 1 μM. However, priming of arterial rings with 1 nM Ang II potentiated PGE 2 -evoked constriction in a concentration dependent manner (Area Under the Curve, AUC untreated 1.784 ± 0.353, AUC Ang II 23.27± 9.820, P<0.05). We tested femoral arteries from EP1, EP2, and EP3 receptor knockout mice. Only the EP3-/- arteries were unable to respond to PGE 2 after Ang II priming (figure below). Pretreatment of arterial rings with 1 μM losartan, an angiotensin receptor antagonist, blocked PGE 2 -induced constrictor effects primed with Ang II (% of KCl, Ang II 21.72 ± 5.296, Ang II + losartan 3.025 ± 1.046, n=3). We have determined that re-addition of extracellular Ca 2+ to a Ca 2+ -free artery restores PGE 2 -induced contractions (n=5) and that the Rho-kinase inhibitor Y-27632 blocks contraction (n=3). Taken together these data are consistent with angiotensin AT1 and prostaglandin EP3 receptors mediating a synergistic Rho-kinase-dependent contractile response. We are continuing to investigate the relationship between Ang II and PGE 2 to determine the physiological relevance this may have in modulating blood pressure.

scholarly journals Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor

2013 ◽  
Vol 304 (7) ◽  
pp. F900-F907 ◽  
Author(s):  
Norma B. Ojeda ◽  
Thomas P. Royals ◽  
Barbara T. Alexander
Keyword(s):  
Blood Pressure ◽  
Glomerular Filtration Rate ◽  
Angiotensin Ii ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Ang Ii ◽  
Intact Male ◽  
Rho Kinase Inhibitor

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg−1·min−1) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls ( P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg−1·min−1) significantly attenuated these hemodynamic changes ( P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced ( P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats.

Abstract 112: The 20-HETE Receptor: a New Player in Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Victor Garcia ◽  
Ankit Gilani ◽  
Brian Shkolnik ◽  
John R Falck ◽  
Varun Pandey ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Smooth Muscle ◽  
Vascular Function ◽  
Vascular Dysfunction ◽  
Arachidonic Acid Metabolite ◽  
Dependent Manner ◽  
Smooth Muscle Contractility ◽  
Blood Pressure Elevation ◽  
Novel Target

Here, we report that GPR75, a G protein-coupled receptor of the Gq rhodopsin subfamily, selectively binds 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450-derived bioactive arachidonic acid metabolite implicated in the pathogenesis of hypertension and cardiovascular diseases. In endothelial cells, 20-HETE binding to GPR75 stimulates β-arrestin recruitment and GIT1-GPR75 association, which further facilitates a c-Src-mediated transactivation of EGFR. This results in downstream signaling pathways which induce ACE expression and decrease NO bioavailability. Knockdown of GPR75 prevents 20-HETE-mediated downstream effects in endothelial cells including EGFR activation and ACE induction. In vascular smooth muscle cells, GPR75-20-HETE pairing is associated with Gα q/11 -and GIT1-mediated PKC-stimulated phosphorylation of MaxiKβ, linking GPR75 activation to 20-HETE-mediated vasoconstriction. We used the conditional Cyp4a12tg mice, which display doxycycline (DOX)-mediated hypertension along with vascular dysfunction and remodeling in a 20-HETE-dependent manner, to assess whether GPR75 is a necessary component of 20-HETE pro-hypertensive actions. Administration of GPR75-targeted shRNA lentiviral particles to DOX-treated Cyp4a12tg mice, which resulted in 80% knockdown of GPR75 knockdown, prevented blood pressure elevation (100±3 vs 135±2 mmHg) and 20-HETE-mediated increases in ACE expression, endothelial dysfunction, smooth muscle contractility and vascular remodeling when compared to DOX-treated Cyp4a12tg mice receiving non-targeted shRNA. The discovery of 20-HETE-GPR75 pairing provides the molecular basis for the signaling and pathophysiological bioactions mediated by 20-HETE in hypertension. These results clearly place GPR75 as a novel target in the control of blood pressure and vascular function.

scholarly journals 151 Nox5 induces vascular dysfunction and arterial remodelling independently of blood pressure elevation in ang ii-infused nox5-expressing mice

Heart ◽  
2017 ◽  
Vol 103 (Suppl 5) ◽  
pp. A111.1-A111 ◽  
Author(s):  
Augusto Montezano ◽  
Adam Harvey ◽  
Francisco Rios ◽  
Wendy Beatie ◽  
Laura McPherson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Dysfunction ◽  
Ang Ii ◽  
Blood Pressure Elevation ◽  
Pressure Elevation

scholarly journals Influence of dietary inorganic nitrate on blood pressure and vascular function in hypertension: prospective implications for adjunctive treatment

2019 ◽  
Vol 127 (4) ◽  
pp. 1085-1094 ◽  
Author(s):  
Ryan M. Broxterman ◽  
D. Taylor La Salle ◽  
Jia Zhao ◽  
Van R. Reese ◽  
Russell S. Richardson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Function ◽  
Vascular Dysfunction ◽  
Adjunctive Treatment ◽  
Beetroot Juice ◽  
Antihypertensive Medications ◽  
Blood Pressure Elevation ◽  
Inorganic Nitrate ◽  
Plasma Nitrite ◽  
Medication Status

Dietary inorganic nitrate (nitrate) is a promising adjunctive treatment to reduce blood pressure and improve vascular function in hypertension. However, it remains unknown if the efficacy of nitrate is dependent upon an elevated blood pressure or altered by medication in patients with hypertension. Therefore, blood pressure and vascular function, measured by passive leg movement (PLM) and flow-mediated dilation (FMD), were assessed following 3 days of placebo (nitrate-free beetroot juice) and nitrate (nitrate-rich beetroot juice) administration in 13 patients (age: 53 ± 12 yr) with hypertension taking antihypertensive medications ( study 1) and in 14 patients (49 ± 13 yr) with hypertension not taking antihypertensive medications ( study 2). In study 1, plasma nitrite concentration was greater for nitrate than placebo (341 ± 118 vs. 308 ± 123 nmol/L, P < 0.05), yet blood pressure and vascular function were unaltered. In study 2, plasma nitrite concentration was greater for nitrate than placebo (340 ± 102 vs. 295 ± 93 nmol/L, P < 0.01). Systolic (136 ± 16 vs. 141 ± 19 mmHg), diastolic (84 ± 13 vs. 88 ± 12 mmHg), and mean (101 ± 12 vs. 106 ± 13 mmHg) blood pressures were lower ( P < 0.05), whereas the PLM change in leg vascular conductance (6.0 ± 3.0 vs. 5.1 ± 2.6 mL·min−1·mmHg−1) and FMD (6.1 ± 2.4% vs. 4.1 ± 2.7%) were greater ( P < 0.05) for nitrate than placebo. The changes in systolic blood pressure ( r = −0.60) and FMD ( r = −0.48) induced by nitrate were inversely correlated ( P < 0.05) to the respective baseline values obtained in the placebo condition. Thus, the efficacy of nitrate to improve blood pressure and vascular function in hypertension appears to be dependent on the degree of blood pressure elevation and vascular dysfunction and not antihypertensive medication status, per se. NEW & NOTEWORTHY Dietary nitrate (nitrate) is a promising intervention to improve blood pressure and vascular function in hypertension. We demonstrate that these beneficial effects of nitrate are inversely related to the baseline value in a continuous manner with no distinction between antihypertensive medication status. Thus, the efficacy of nitrate to improve blood pressure and vascular function in hypertension appears to be dependent on the degree of blood pressure elevation and vascular dysfunction and not antihypertensive mediation status.

scholarly journals Differences in angiotensin (1–7) between men and women

2015 ◽  
Vol 308 (9) ◽  
pp. H1171-H1176 ◽  
Author(s):  
Jennifer C. Sullivan ◽  
Paula Rodriguez-Miguelez ◽  
Margaret A. Zimmerman ◽  
Ryan A. Harris
Keyword(s):  
Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Vascular Function ◽  
Plasma Concentrations ◽  
Ang Ii ◽  
Cross Sectional ◽  
Men And Women ◽  
Time To Peak ◽  
Artery Flow ◽  
Age Range

In experimental animal models of hypertension, angiotensin (1–7) [ANG-(1–7)] is higher in females compared with males; however, it is less clear whether the same applies to humans. Therefore, this study sought to compare circulating concentrations of ANG-(1–7) in apparently healthy men and women under normal physiological conditions. With the use of a cross-sectional experimental design, blood was collected in EDTA anticoagulant from 42 volunteers (21 men and 21 women; and age range, 19–48 yr) for analysis of plasma concentrations of ANG-(1–7) and ANG II. Blood pressure was measured and vascular endothelial function was determined ( n = 25) using the brachial artery flow-mediated dilation (FMD) test. As a result, women exhibited a higher circulating concentration of ANG-(1–7) ( P = 0.04) compared with men, whereas values of ANG II were similar between groups. Baseline arterial diameter, peak diameter, and shear rate were significantly greater ( P < 0.02) in men compared with women. No significant differences in FMD, FMD normalized for shear, or time to peak dilation were observed between men and women. In addition, a positive correlation between ANG-(1–7) and FMD ( P = 0.04) and negative association between ANG-(1–7) with ANG II ( P = 0.01) were only identified in men, whereas a positive relationship between ANG-(1–7) and diastolic blood pressure ( P = 0.03) was observed in women. In conclusion:, women exhibit significantly higher plasma concentrations of ANG-(1–7) compared with men. In addition, this study describes a relationship between ANG-(1–7), vascular function, and diastolic blood pressure that appears to be sex dependent.

Abstract 048: Expression of a Hypertension-causing Mutation in Cullin 3 (CUL3Δ9) Specifically in Smooth Muscle Causes Vascular Dysfunction and Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Larry N Agbor ◽  
Jing Wu ◽  
Stella-Rita C Ibeawuchi ◽  
Chunyan Hu ◽  
Deborah R Davis ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Transgenic Mice ◽  
Basilar Artery ◽  
Kinase Inhibitor ◽  
Vascular Dysfunction ◽  
Rho Kinase ◽  
Dominant Negative ◽  
Nitric Oxide Donor ◽  
Ang Ii ◽  
Cullin 3

Pseudohypoaldosteronism type II (PHAII) patients with mutations in cullin 3 (CUL3) resulting in exon 9 deletion (CUL3Δ9), exhibit severe early onset hypertension correlated with impaired kidney function. However, the extra-renal mechanisms remain uninvestigated. We hypothesized that expression of CUL3Δ9 protein in smooth muscle in mice impairs endogenous wildtype CUL3 (CUL3-WT) function and causes vascular dysfunction and hypertension. We generated transgenic mice inducibly expressing CUL3Δ9 protein in smooth muscle (S-CUL3Δ9) and measured blood pressure (BP) by radiotelemetry. We assessed vascular responses in the cerebral basilar artery and aorta using a pressurized and a wire myograph, respectively. S-CUL3Δ9 mice exhibited reduced expression of endogenous CUL3WT protein compared to non-transgenic (NT) in aorta. Systolic BP was significantly increased in S-CUL3Δ9 mice (127±2 S-CUL3Δ9 vs 117±1 NT, p=0.02). Basilar artery from S-CUL3Δ9 mice exhibited significantly impaired vasorelaxation to acetylcholine (ACh) (at 100 μM: 15±4% S-CUL3Δ9 vs 65±5% NT, p<0.0001), and to the nitric oxide donor sodium nitroprusside (SNP) (at 100 μM: 59±2% S-CUL3Δ9 vs 90±5% NT, p<0.05). Vasocontraction to angiotensin II (Ang II), phenylephrine (PE) and to endothelin 1 (ET-1) were significantly elevated in S-CUL3Δ9 transgenic mice. Consistent with data from basilar artery, aorta from S-CUL3Δ9 transgenic mice exhibited impaired ACh-mediated relaxation (at 100 μM: 55±2% S-CUL3Δ9 vs 71±7% NT, p<0.0001). Total RhoA protein was significantly elevated in aorta of S-CUL3Δ9 transgenic mice (1.6±0.2 S-CUL3Δ9 vs 1.0±0.1 NT, P<0.05). Serotonin stimulation caused a significant increase in active RhoA in S-CUL3Δ9 aorta (1.83±0.04 S-CUL3Δ9 versus 1.52±0.06 NT, p=0.005). Preincubation with the Rho-kinase inhibitor (Y27632) restored endothelium-dependent relaxation in basilar artery and aorta of S-CUL3Δ9 mice. Ang II infusion via osmotic minipump (200 ng/kg/min) resulted in elevated BP response (Systolic BP: 147 ± 2 S-CUL3Δ9 versus 130 ± 5 NT, p=0.04) and increased aortic stiffening in S-CUL3Δ9 mice. We conclude that CUL3Δ9 acts in a dominant negative manner by interfering with CUL3-WT and contributes at least in part to hypertension via its effects on the vasculature.

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