The direct renin inhibitor aliskiren improves vascular remodelling in transgenic rats harbouring human renin and angiotensinogen genes

In the present study, we tested the hypothesis that chronic treatment with the direct rennin inhibitor aliskiren improves the remodelling of resistance arteries in dTGR (double-transgenic rats). dTGR (5 weeks) were treated with aliskiren (3 mg/kg of body mass per day) or ramipril (1 mg/kg of body mass per day) for 14 days and compared with age-matched vehicle-treated dTGR. BP (blood pressure) was similarly reduced in both aliskiren-treated and ramipril-treated rats compared with control dTGR (167±1 and 169±2 mmHg compared with 197±4 mmHg respectively; P<0.05). The M/L (media-to-lumen) ratio assessed on pressurized preparations was equally reduced in aliskiren-treated and ramipril-treated rats compared with controls (6.3±0.5 and 6.4±0.2% compared with 9.8±0.4% respectively; P<0.05). Endothelium-dependent and -independent relaxations were similar among the groups. L-NAME (NG-nitro-L-arginine methyl ester) significantly reduced acetylcholine-induced dilation in drug-treated dTGR. This effect was significantly more prominent in aliskiren-treated rats. eNOS (endothelial NO synthase) expression showed a 2-fold increase only in aliskiren-treated dTGR as compared with controls (P<0.01) and ramipril-treated dTGR (P<0.05). Plasma nitrite, as an index of NO production, was significantly increased in dTGR treated with either aliskiren or ramipril compared with controls. Only aliskiren induced a 2-fold increase in plasma nitrite, which was significantly greater than that induced by ramipril (P<0.05). gp91phox expression and ROS (reactive oxygen species) production in aorta were significantly and similarly reduced by both drugs. In conclusion, equieffective hypotensive doses of aliskiren or ramipril reduced the M/L ratio of mesenteric arteries and improved oxidative stress in dTGR. However, only aliskiren increased further NO production in the vasculature. Hence, in dTGR, direct renin inhibition induces favourable effects similar to that induced by ACE (angiotensin-converting enzyme) inhibition in improving vascular remodelling through different mechanisms.

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Abstract P500: Activation of the Heterodimeric Erythropoietin /β-Common Receptor Impairs Acetylcholine Mediated Vasodilation in Mouse Mesenteric Arterioles

Hypertension ◽

10.1161/hyp.70.suppl_1.p500 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Cody R Kilar ◽

YanPeng Diao ◽

Larysa Sautina ◽

Sivakumar Sekharan ◽

Shahar Keinan ◽

...

Keyword(s):

Sodium Nitroprusside ◽

Vascular Complications ◽

Mesenteric Arteries ◽

No Production ◽

Resistance Arteries ◽

Inhibitory Peptide ◽

Receptor Complexes ◽

Common Receptor ◽

Potent Vasodilator ◽

Selective Impairment

Erythropoietin (EPO) increases systemic vascular resistance and blood pressure. However, endothelial cells cultured in the presence of EPO demonstrate increased production of the potent vasodilator, nitric oxide (NO). The mechanism by which EPO causes vasoconstriction despite stimulating NO production may be dependent on its ability to differentially activate the two receptor complexes, the homodimeric EPO (EPOR 2 ) and the heterodimeric EPOR/β-common receptor (βCR). Objective: The purpose of this study was to investigate the contribution of the EPOR 2 and βCR receptor to the vasoactive properties of EPO. Methods: First order, mesenteric arteries isolated from 16-week old male C57BL/6 mice were cannulated and perfused using a pressure arteriography system. To determine the contribution of each receptor complex, arteries were incubated with EPO stimulating peptide (ESP) which binds and activates only the heterodimeric EPOR/βCR complex or EPO which activates both receptors, 20 min prior to evaluation of vasoconstrictor (phenylephrine and potassium chloride), endothelium-dependent (acetylcholine, bradykinin, A23187) and -independent (sodium nitroprusside) vasodilator responses. Additionally, we studied the effect of a novel βCR inhibitory peptide (βIP) which was developed in silico and validated by demonstrating that it selectively inhibits binding of ligands to the βCR. Results: Acetylcholine induced vasodilation was impaired in arteries pretreated with EPO or ESP by 100% and 60%, respectively. EPO and ESP did not affect endothelium-dependent vasodilation by Bradykinin or A23187, endothelium-independent vasodilation by sodium nitroprusside, or vasoconstriction by phenylephrine and KCl. The βIP prevented the impairment of acetylcholine-induced vasodilation by EPO and ESP. Conclusion: Together, our findings suggest that activation of the heterodimeric EPOR/βCR leads to selective impairment of ACh-mediated vasodilator response in mouse mesenteric resistance arteries. Thus the βCR might have a role in mediating hypertensive effects of EPO. Therapeutic inhibition of the βCR might prevent vascular complications of EPO without affecting erythropoiesis.

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Abstract MP31: Peripheral Vascular Dysfunction In A Model Of Small Vessel Disease Of The Brain (CADASIL) Involves Impaired Redox-sensitive Cyclic GMP/PKG Signaling

Hypertension ◽

10.1161/hyp.76.suppl_1.mp31 ◽

2020 ◽

Vol 76 (Suppl_1) ◽

Author(s):

Karla B Neves ◽

Hannah Morris ◽

Rheure Alves-lopes ◽

Augusto C Montezano ◽

Rhian M Touyz

Keyword(s):

Soluble Guanylate Cyclase ◽

Small Vessel Disease ◽

Vascular Dysfunction ◽

Plasma Lipid ◽

Fold Increase ◽

Mesenteric Arteries ◽

Small Vessel ◽

Resistance Arteries ◽

Vessel Disease ◽

The Brain

CADASIL, a monogenic condition due to Notch3 mutations, is a very aggressive small vessel disease of the brain resulting in premature vascular dementia and stroke. Changes in cerebral vessels include vascular dysfunction and narrowing, and accumulation of granular osmiophilic material (GOM). It is not clear whether small peripheral arteries undergo similar damage. Therefore, our aim is to assess vascular dysfunction and associated mechanisms in mesenteric resistance arteries from CADASIL mice. Mesenteric arteries (MA) from male CADASIL-causing Notch3 mutation (TgNotch3 R169C ) and wildtype (TgNotch3 WT ) mice (6 months old) were investigated. GOM deposits in MA from CADASIL mice were identified by electron microscopy. mRNA expression of Notch3 (WT: 2.0±0.5 vs. 6.0±1.3) and its downstream target HeyL (WT: 1.1±0.4 vs. 2.9±0.6) was augmented in CADASIL mice (p<0.01), suggesting increased Notch3 activation. CADASIL mice exhibited endothelial-dependent (Emax 109.9±7.4 vs. 81.3±5.4) and -independent dysfunction (pD 2 7.8±0.1 vs. 6.8±0.3); effects associated with increased eNOS inhibition (p-Thr 495 ) (1.8-fold increase) and decreased cGMP levels (1.2±0.2 vs. 0.59±0.2) (p<0.05). Plasma lipid peroxidation (0.8±0.1 vs. 2.0±0.3; p<0.05) and vascular reactive oxygen species (ROS) production (7.2±1.9 vs. 75.4±35.0; p<0.05) were increased in TgNotch3 R169C mice; processes associated with upregulation of soluble guanylate cyclase (sGC) oxidation and decreased sGC activity. H 2 O 2 levels were decreased in TgNotch3 R169C mice (1.9±0.2 vs. 1.1±1.9; p<0.05), which was associated with reduced activation of protein kinase G (PKG). Observations in TgNotch3 R169C mice were recapitulated in human CADASIL, where ROS levels (0.8±0.1 vs. 4.1±2.7; p<0.05) and sGC oxidation were also increased. Our findings demonstrate that the vasculopathy associated with a CADASIL Notch3 gain-of-function mutation in peripheral small vessels involves reduction in eNOS activation and redox-sensitive processes leading to impaired sGC/cGMP signalling pathway. We identify a potential new therapeutic target in CADASIL, for which there are no disease-specific treatments.

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Abstract MP10: Early Functional and Structural Alterations of Resistance Arteries in Mice Treated with an Inhibitor of the Vascular Endothelial Growth Factor Receptor

Hypertension ◽

10.1161/hyp.64.suppl_1.mp10 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

CARMINE SAVOIA ◽

Emanuele Arrabito ◽

Augusto C Montezano ◽

Carmine Nicoletti ◽

Heather Y Small ◽

...

Keyword(s):

Vascular Endothelial Growth Factor ◽

Growth Factor ◽

Vascular Remodeling ◽

Growth Factor Receptor ◽

Mesenteric Arteries ◽

No Production ◽

Vascular Endothelial ◽

Resistance Arteries ◽

Structural Alterations ◽

Endothelial Growth Factor

Background: Inhibition of tyrosine kinases receptors such as vascular endothelial growth factor receptor (VEGFR) and epidermal growth factor receptor (EGFR) improves outcomes in patients with cancers. Only VEGFR inhibitors, however, induce severe hypertension whose mechanisms remain unclear. We hypothesized that VEGFR inhibitors may induce early vascular functional and structural alterations, that may precede the development of hypertension. Methods and results: Normotensive SV-129 mice (8 weeks old, 5 for each group) were treated or not with the VEGFR inhibitor Vatalanib (VAT, 100 mg/Kg/day) or the EGFR inhibitor Gefitinib (GEF, 100 mg/Kg/day). Vehicle-treated control mice were also studied. Blood pressure (BP) was measured by tail-cuff method. Endothelium-dependent and -independent relaxations were assessed by concentration-response curves to acetylcholine (1 nM to 100 μM) ± L-NAME (100 μM) and sodium nitroprusside (10 nM to 1 mM) respectively, in mesenteric arteries pre-contracted with norepinephrine (10 μM). Media-to-lumen ratio (M/L, an index of early vascular remodeling), and cross sectional area (CSA) were evaluated on pressurized preparations. After two weeks, BP was similarly preserved in both VAT- and GEF-treated mice as compared to vehicle-treated mice (89.8±1.5 mmHg and 87.2±2.8 mmHg vs 92.2±2.2 mmHg, respectively, NS). Endothelium-dependent relaxation was similarly preserved in vehicle-treated and GEF-treated mice, whereas it was reduced in VAT-treated mice (-17% vs vehicle-treated mice, P<0.05). L-NAME blunted acetylcholine-induced relaxation in all groups except in VAT-treated mice, suggesting an impairment of NO production only in this group. Endothelium-independent relaxation was similar in all groups. Only VAT-treated mice presented increased M/L as compared to vehicle-treated mice (6.3±0.1% vs 5.4±0.1%, P<0.05). M/L resulted similar in GEF-treated and vehicle-treated mice. CSA was similar in all groups. Conclusion: In normotensive mice, only VAT promoted early vascular alterations such as endothelial dysfunction and vascular remodeling in resistance arteries. Those changes in the vasculature are distinctive of hypertension and might precede and sustain the development of the hypertensive disease.

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Endothelial dysfunction and arterial pressure regulation during early diabetes in mice: roles for nitric oxide and endothelium-derived hyperpolarizing factor

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00807.2006 ◽

2007 ◽

Vol 293 (2) ◽

pp. R707-R713 ◽

Cited By ~ 21

Author(s):

Sharyn M. Fitzgerald ◽

Barbara K. Kemp-Harper ◽

Helena C. Parkington ◽

Geoffrey A. Head ◽

Roger G. Evans

Keyword(s):

Nitric Oxide ◽

Endothelial Dysfunction ◽

Arterial Pressure ◽

Early Stage ◽

Mesenteric Arteries ◽

No Production ◽

Wild Type ◽

Early Diabetes ◽

Diabetes In Mice ◽

Vehicle Treatment

We determined whether nitric oxide (NO) counters the development of hypertension at the onset of diabetes in mice, whether this is dependent on endothelial NO synthase (eNOS), and whether non-NO endothelium-dependent vasodilator mechanisms are altered in diabetes in mice. Male mice were instrumented for chronic measurement of mean arterial pressure (MAP). In wild-type mice, MAP was greater after 5 wk of Nω-nitro-l-arginine methyl ester (l-NAME; 100 mg·kg−1·day−1 in drinking water; 97 ± 3 mmHg) than after vehicle treatment (88 ± 3 mmHg). MAP was also elevated in eNOS null mice (113 ± 4 mmHg). Seven days after streptozotocin treatment (200 mg/kg iv) MAP was further increased in l-NAME-treated mice (108 ± 5 mmHg) but not in vehicle-treated mice (88 ± 3 mmHg) nor eNOS null mice (104 ± 3 mmHg). In wild-type mice, maximal vasorelaxation of mesenteric arteries to acetylcholine was not altered by chronic l-NAME or induction of diabetes but was reduced by 42 ± 6% in l-NAME-treated diabetic mice. Furthermore, the relative roles of NO and endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced vasorelaxation were altered; the EDHF component was enhanced by l-NAME and blunted by diabetes. These data suggest that NO protects against the development of hypertension during early-stage diabetes in mice, even in the absence of eNOS. Furthermore, in mesenteric arteries, diabetes is associated with reduced EDHF function, with an apparent compensatory increase in NO function. Thus, prior inhibition of NOS results in endothelial dysfunction in early diabetes, since the diabetes-induced reduction in EDHF function cannot be compensated by increases in NO production.

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Pregnancy Enhances the Angiotensin (Ang)-(1–7) Vasodilator Response in Mesenteric Arteries and Increases the Renal Concentration and Urinary Excretion of Ang-(1–7)

Endocrinology ◽

10.1210/en.2003-0009 ◽

2003 ◽

Vol 144 (8) ◽

pp. 3338-3343 ◽

Cited By ~ 35

Author(s):

Liomar A. A. Neves ◽

Aleck F. Williams ◽

David B. Averill ◽

Carlos M. Ferrario ◽

Michael P. Walkup ◽

...

Keyword(s):

Urinary Excretion ◽

Excretion Rate ◽

Virgin Female ◽

Cardiovascular Regulation ◽

Mesenteric Arteries ◽

Female Rats ◽

Resistance Arteries ◽

Urinary Excretion Rate ◽

Response Curves ◽

Mesenteric Vessels

Abstract The vasoactive effect of angiotensin (Ang)-(1–7) in mesenteric resistance arteries together with its plasma and kidney concentration and urinary excretion was assessed in pregnant and virgin rats. Mesenteric arteries (230–290 μm) were mounted in a pressurized myograph system and Ang-(1–7) concentration-dependent response curves (10−10–10−5m) were determined in arteries preconstricted with endothelin-1 (10−7m). The Ang-(1–7) response was investigated in vessels with and without pretreatment with the Ang-(1–7) antagonist [d-[Ala7]-Ang-(1–7)] (10−7m). Ang-(1–7) caused a significantly enhanced, concentration-dependent dilation of mesenteric vessels (EC50 = 2.7 nm) from pregnant compared with virgin female rats. d-[Ala7]-Ang-(1–7) eliminated the vasodilator effect of Ang-(1–7). There was no significant change in plasma concentration of Ang-(1–7) in pregnant animals. On the other hand, 24 h urinary excretion and kidney concentration of Ang-(1–7) were significantly higher in pregnant animals. The increased mesenteric dilation to Ang-(1–7) with enhanced kidney concentration and 24 h urinary excretion rate of Ang-(1–7) suggests an important role for this peptide in cardiovascular regulation during pregnancy.

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Constituents of Talisia nervosa with Potential Utility against Metabolic Syndrome

Natural Product Communications ◽

10.1177/1934578x1901400114 ◽

2019 ◽

Vol 14 (1) ◽

pp. 1934578X1901400 ◽

Cited By ~ 1

Author(s):

Yelkaira Vásquez ◽

Jianping Zhao ◽

Shabana I. Khan ◽

Mahabir P. Gupta ◽

Ikhlas A. Khan

Keyword(s):

Metabolic Syndrome ◽

Ethanolic Extract ◽

Fold Increase ◽

No Production ◽

Methyl Gallate ◽

Potent Effect ◽

Cellular Assays ◽

The Metabolic Syndrome ◽

Isolation And Characterization ◽

Bioassay Guided Fractionation

This study is focused on the isolation and characterization of bioactive secondary metabolites from the ethanolic extract of stems of the Panamanian plant Talisia nervosa Radlk, through a series of target-based cellular assays related to the metabolic syndrome (MetS): a combination of type 2 Diabetes Mellitus (T2DM), hypercholesterolemia, inflammation, and obesity. Bioassay guided fractionation allowed the isolation of four known compounds: (-)-catechin (1), methyl gallate (2), ethyl gallate (3), and ß-D-glucopyranose,1,4,6-tris(3,4,5-trihydroxybenzoate) (4). This is the first report of (-)-catechin (1) and ß-D-glucopyranose,1,4,6-tris (3,4,5-trihydroxybenzoate) (4) from T. nervosa. Among the isolates, 1 activated PPARγ, but had no effect on PPARα. Compounds 2 -4 activated PPARα, PPARγ and LXR. Interestingly, 2 was stronger than 3 towards all three targets. Methyl gallate (2) showed the most potent effect toward both PPARα and PPARγ with an increase of 3.0 and 13-fold, respectively, while 4 was most potent in activating LXR with a fold induction of 5.3 at concentrations of 100 μg/mL. The nitric oxide (NO) production was reduced by compounds 2 and 3 with IC50 values of 7.0 and 7.5 μg/mL, respectively. ß-D-glucopyranose,1,4,6-tris (3,4,5-trihydroxybenzoate) 4) did not cause a significant increase in adipogenesis despite its strong PPARγ agonistic action (8 6-fold increase) and may represent a good candidate for the treatment of MetS without the undesirable side effect of weight gain.

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Simulated microgravity alters rat mesenteric artery vasoconstrictor dynamics through an intracellular Ca2+ release mechanism

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00084.2008 ◽

2008 ◽

Vol 294 (5) ◽

pp. R1577-R1585 ◽

Cited By ~ 20

Author(s):

Patrick N. Colleran ◽

Bradley J. Behnke ◽

M. Keith Wilkerson ◽

Anthony J. Donato ◽

Michael D. Delp

Keyword(s):

Temporal Dynamics ◽

Orthostatic Intolerance ◽

Mesenteric Arteries ◽

Release Mechanism ◽

Resistance Arteries ◽

Receptor Mrna ◽

Cardiovascular Deconditioning ◽

Rat Mesenteric Artery ◽

Mrna And Protein Expression

Previous work has shown that orthostatic hypotension associated with cardiovascular deconditioning results from inadequate peripheral vasoconstriction. We used the hindlimb-unloaded (HU) rat in this study as a model to induce cardiovascular deconditioning. The purpose of this study was to test the hypothesis that 14 days of HU diminishes vasoconstrictor responsiveness of mesenteric resistance arteries. Mesenteric resistance arteries from control ( n = 43) and HU ( n = 44) rats were isolated, cannulated, and pressurized to 108 cm H2O for in vitro experimentation. Myogenic (intralumenal pressure ranging from 30 to 180 cm H2O), KCl (2–100 mM), norepinephrine (NE, 10−9–10−4 M) and caffeine (1–20 mM) induced vasoconstriction, as well as the temporal dynamics of vasoconstriction to NE, were determined. The active myogenic and passive pressure responses were unaltered by HU when pressures remained within physiological range. However, vasoconstrictor responses to KCl, NE, and caffeine were diminished by HU, as well as the rate of constriction to NE (C, 14.8 ± 3.6 μm/s vs. HU 7.6 ± 1.8 μm/s). Expression of sarcoplasmic reticulum Ca2+ATPase 2 and ryanodine 3 receptor mRNA was unaffected by HU, while ryanodine 2 receptor mRNA and protein expression were diminished in mesenteric arteries from HU rats. These data suggest that HU-induced and microgravity-associated orthostatic intolerance may be due, in part, to an attenuated vasoconstrictor responsiveness of mesenteric resistance arteries resulting from a diminished ryanodine 2 receptor Ca2+ release mechanism.

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Relationship between flow rate and NO production in postnatal mesenteric arteries

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2001.280.1.g43 ◽

2001 ◽

Vol 280 (1) ◽

pp. G43-G50 ◽

Cited By ~ 16

Author(s):

Kristina M. Reber ◽

Gennifer M. Mager ◽

Charles E. Miller ◽

Philip T. Nowicki

Keyword(s):

Flow Rate ◽

Kinase Inhibitor ◽

Age Groups ◽

Mesenteric Arteries ◽

No Production ◽

Herbimycin A ◽

Wide Range ◽

Intracellular Ca ◽

Controlled Flow

We studied mesenteric arterial arcades from 3- and 35-day-old swine to determine the relationship between perfusate flow rate and release of nitric oxide (NO) into mesenteric effluent. Mesenteric arterial arcades were perfused under controlled-flow conditions with a peristaltic pump using warm oxygenated Krebs buffer. Basal rates of NO production were 43.6 ± 4.2 vs. 12.1 ± 2.5 nmol/min in 3- vs. 35-day-old mesentery during perfusion at in vivo flow rates (9 vs. 20 ml/min, respectively). Rate of NO production was directly related to flow rate over a wide range of flows (5–40 ml/min) in 3- but not 35-day-old mesentery. Both age groups demonstrated a brisk, albeit brief, increase in NO production in response to infusion of NO-dependent vasodilator substance P (10−8 M/min). Tyrosine kinase inhibitor herbimycin A andl-arginine analog l-NMMA significantly attenuated flow-induced increase in NO production, and phosphatase inhibitor phenylarsine oxide increased magnitude of flow-induced increase in NO production in 3-day-olds. Removal of extracellular Ca2+ and depletion of intracellular Ca2+ stores (Ca2+-free Krebs with EGTA plus thapsigargin) had no effect on NO production in either group. Thus, basal rate of NO production is greater in mesenteric arterial arcades from 3- than from 35-day old swine, a direct relationship between flow rate and NO production rate is present in mesentery from 3- but not 35-day-olds, and phosphorylation events are necessary for this interaction to occur.

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Abstract 17415: Mitochondrial Ca2+/Calmodulin-Dependent Kinase II Inhibition Changes the Calcium Homeostasis in the Endothelium and Decreases the Vascular Relaxation in Mesenteric Arteries

Circulation ◽

10.1161/circ.142.suppl_3.17415 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Celio Damacena De Angelis ◽

Daniel W Nuno ◽

Olha Koval ◽

Kathryn G Lamping ◽

Isabella M Grumbach

Keyword(s):

Calcium Release ◽

Mesenteric Arteries ◽

Lower Sensitivity ◽

No Production ◽

Vascular Relaxation ◽

Fura 2 ◽

The Right ◽

Oxide Synthase ◽

Mesenteric Resistance Artery ◽

Endothelial Nitric Oxide

Introduction: The Ca2+/Calmodulin-dependent Kinase II (CaMKII) is present in mitochondria and cytosol. In mitochondria, it regulates the mitochondrial Ca 2+ uptake via the mitochondrial Ca2+ uniporter. Since endothelial nitric oxide synthase activity is regulated by intracellular [Ca2+], we hypothesized that it affects cytosolic Ca2+, NO production and ACh-dependent vasodilation. Hypothesis: Inhibition of mitochondrial CaMKII in endothelium increases the cytosolic [Ca2+], and decreases vasorelaxation by Acetylcholine. Methods: CaMKII in mitochondria was inhibited through expression of the mitochondria-targeted CaMKII inhibitor peptide (mito-CaMKIIN) in a novel transgenic mouse model (endo-mtCaMKIIN) in endothelial cells only or delivered by adenoviral transduction (Ad-mtCaMKIIN) in human Aortic Endothelium cells (HAEC). In HAEC, cytosolic Ca2+ levels (by FURA-2 AM), eNOS activation and NOx levels were measured. Results: The basal Ca2+ levels were higher in the cytosol of mitoCaMKIIN cells (1.08 ± 0.02 Fura-2 ratio normalized by control, p<0.05). Thapsigargin-induced ER Ca 2+ release was significantly higher with mitoCaMKIIN (AUC 0.252 ± 0.027 versus 0.112 ± 0.01275, p<0.05), whereas cytosolic Ca 2+ levels after ACh were reduced (AUC 0.191 ± 0.025 versus 0.435 ± 0.054). Higher levels of phosphorylation of eNOS at Ser1177 and Thr495 sites were seen at baseline. The concentration-response curve of vascular relaxation to acetylcholine and SNP shifted to the right (p<0.05) in mesenteric resistance artery of mitoCaMKIIN mice. Conclusions: The inhibition of mitochondrial CaMKII in the endothelium increases the cytosolic levels, endoplasmic reticulum storage of calcium and eNOS phosphorylation. However, there are lower calcium release and lower sensitivity to acetylcholine and SNP.

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Abstract P217: Nox Compartmentalization, Protein Oxidation and ER Stress in Vascular Smooth Muscle Cells in Hypertension

Hypertension ◽

10.1161/hyp.70.suppl_1.p217 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Livia L Camargo ◽

Augusto C Montezano ◽

Adam Harvey ◽

Sofia Tsiropoulou ◽

Katie Hood ◽

...

Keyword(s):

Er Stress ◽

Protein Oxidation ◽

Vascular Function ◽

Vascular Reactivity ◽

Stress Proteins ◽

Vascular Dysfunction ◽

Mesenteric Arteries ◽

Resistance Arteries ◽

Post Translational Modification ◽

Wistar Kyoto

In hypertension, activation of NADPH oxidases (Noxs) is associated with oxidative stress and vascular dysfunction. The exact role of each isoform in hypertension-associated vascular injury is still unclear. We investigated the compartmentalization of Noxs in VSMC from resistance arteries of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). Expression of Nox1 and Nox4 was increased in SHR cells (96.6±28.7% and 48.2±21.2% vs WKY, p<0.05), as well as basal ROS levels measured by chemiluminescence (110.2±26.4% vs WKY, p<0.05) and amplex red (105.2±33.2% vs WKY, p<0.05). Phosphorylation of unfolded protein response activators, PERK and IRE1α, and expression of ER chaperone BiP were elevated in SHR cells (p<0.05 vs WKY), indicating activation of ER stress response. Immunoblotting after organelle fractionation demonstrated that Noxs are expressed in an organelle-specific manner, with Nox1, 2 and 4 present in plasma membrane, ER and nucleus, but not in mitochondria. In SHR cells, NoxA1ds (Nox1 inhibitor, 10μM) and GKT136901 (Nox1/4 inhibitor, 10μM) decreased AngII-induced ROS levels (p<0.001 vs Ctl). Additionally, mito-tempol (mitochondrial-targeted antioxidant, 50nM) and 4-PBA (ER stress inhibitor, 1mM) decreased basal ROS levels in SHR cells (p<0.05 vs Ctl). Furthermore, oxidation of the antioxidant enzymes Peroxiredoxins (Prx) was increased in SHRSP compared to WKY (2.51±0.14 vs 0.56±0.07, p<0.001). One-dimensional isoelectric focusing revealed that cytosolic Prx2 and mitochondrial Prx3 were more oxidized in SHRSP than WKY cells. Using a biotin-tagged dimedone-based probe (DCP-Bio) we identified oxidation of ER stress proteins BiP and IRE1. To investigate the effect of protein oxidation in vascular function, vascular reactivity was evaluated in isolated mesenteric arteries. Inhibition of general oxidation (DTT 1mM; Emax: 111.7±33.1) and peroxiredoxin (Conoidin A 10nM; Emax: 116.0±7.3) reduces vascular contraction in response to noradrenalin in WKY rats (Emax: 166.6±30.2; p<0.05). These findings suggest an important role for Nox1/4 in redox-dependent organelle dysfunction and post-translational modification of proteins, processes that may play an important role in vascular dysfunction in hypertension.

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