scholarly journals The NRF2 knockout rat: a new animal model to study endothelial dysfunction, oxidant stress, and microvascular rarefaction

2016 ◽  
Vol 310 (4) ◽  
pp. H478-H487 ◽  
Author(s):  
Jessica R. C. Priestley ◽  
Katie E. Kautenburg ◽  
Marc C. Casati ◽  
Bradley T. Endres ◽  
Aron M. Geurts ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Endothelial Dysfunction ◽  
Oxidant Stress ◽  
Antioxidant Defenses ◽  
Start Codon ◽  
Heme Oxygenase 1 ◽  
Ang Ii ◽  
Wild Type ◽  
Transcription Activator ◽  
Therapeutic Benefits

Nuclear factor (erythroid-derived 2)-like-2 (NRF2) is a master antioxidant and cell protective transcription factor that upregulates antioxidant defenses. In this study we developed a strain of Nrf2 null mutant rats to evaluate the role of reduced NRF2-regulated antioxidant defenses in contributing to endothelial dysfunction and impaired angiogenic responses during salt-induced ANG II suppression. Nrf2−/− mutant rats were developed using transcription activator-like effector nuclease technology in the Sprague-Dawley genetic background, and exhibited a 41-bp deletion that included the start codon for Nrf2 and an absence of immunohistochemically detectable NRF2 protein. Expression of mRNA for the NRF2-regulated indicator enzymes heme oxygenase-1, catalase, superoxide dismutase 1, superoxide dismutase 2, and glutathione reductase was significantly lower in livers of Nrf2−/− mutant rats fed high salt (HS; 4% NaCl) for 2 wk compared with wild-type controls. Endothelium-dependent dilation to acetylcholine was similar in isolated middle cerebral arteries (MCA) of Nrf2−/− mutant rats and wild-type littermates fed low-salt (0.4% NaCl) diet, and was eliminated by short-term (3 days) HS diet in both strains. Low-dose ANG II infusion (100 ng/kg sc) reversed salt-induced endothelial dysfunction in MCA and prevented microvessel rarefaction in wild-type rats fed HS diet, but not in Nrf2−/− mutant rats. The results of this study indicate that suppression of NRF2 antioxidant defenses plays an essential role in the development of salt-induced oxidant stress, endothelial dysfunction, and microvessel rarefaction in normotensive rats and emphasize the potential therapeutic benefits of directly upregulating NRF2-mediated antioxidant defenses to ameliorate vascular oxidant stress in humans.

scholarly journals A Pharmacologic “Stress Test” for Assessing Select Antioxidant Defenses in Patients with CKD

2020 ◽  
Vol 15 (5) ◽  
pp. 633-642 ◽  
Author(s):  
Richard A. Zager ◽  
Ali C.M. Johnson ◽  
Alvaro Guillem ◽  
Jeff Keyser ◽  
Bhupinder Singh
Keyword(s):  
Kidney Disease ◽  
Healthy Volunteers ◽  
Stress Test ◽  
Oxidant Stress ◽  
Pharmacologic Stress ◽  
Antioxidant Defenses ◽  
Heme Oxygenase 1 ◽  
High Dose ◽  
Clinical Trial Registry ◽  
Antioxidant Proteins

Background and objectivesOxidative stress is a hallmark and mediator of CKD. Diminished antioxidant defenses are thought to be partly responsible. However, there is currently no way to prospectively assess antioxidant defenses in humans. Tin protoporphyrin (SnPP) induces mild, transient oxidant stress in mice, triggering increased expression of select antioxidant proteins (e.g., heme oxygenase 1 [HO-1], NAD[P]H dehydrogenase [quinone] 1 [NQO1], ferritin, p21). Hence, we tested the hypothesis that SnPP can also variably increase these proteins in humans and can thus serve as a pharmacologic “stress test” for gauging gene responsiveness and antioxidant reserves.Design, setting, participants, & measurementsA total of 18 healthy volunteers and 24 participants with stage 3 CKD (n=12; eGFR 30–59 ml/min per 1.73 m2) or stage 4 CKD (n=12; eGFR 15–29 ml/min per 1.73 m2) were injected once with SnPP (9, 27, or 90 mg). Plasma and/or urinary antioxidant proteins were measured at baseline and for up to 4 days post-SnPP dosing. Kidney safety was gauged by serial measurements of BUN, creatinine, eGFR, albuminuria, and four urinary AKI biomarkers (kidney injury molecule 1, neutrophil gelatinase-associated lipocalin, cystatin C, and N-acetyl glucosaminidase).ResultsPlasma HO-1, ferritin, p21, and NQO1 were all elevated at baseline in CKD participants. Plasma HO-1 and urine NQO1 levels each inversely correlated with eGFR (r=−0.85 to −0.95). All four proteins manifested statistically significant dose- and time-dependent elevations after SnPP injection. However, marked intersubject differences were observed. p21 responses to high-dose SnPP and HO-1 responses to low-dose SnPP were significantly suppressed in participants with CKD versus healthy volunteers. SnPP was well tolerated by all participants, and no evidence of nephrotoxicity was observed.ConclusionsSnPP can be safely administered and, after its injection, the resulting changes in plasma HO-1, NQO1, ferritin, and p21 concentrations can provide information as to antioxidant gene responsiveness/reserves in subjects with and without kidney disease.Clinical Trial registry name and registration numberA Study with RBT-1, in Healthy Volunteers and Subjects with Stage 3–4 Chronic Kidney Disease, NCT0363002 and NCT03893799

Genomics of cardiac remodeling in angiotensin II-treated wild-type and LOX-1-deficient mice

2010 ◽  
Vol 42 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Bum-Yong Kang ◽  
Changping Hu ◽  
Sunhyo Ryu ◽  
Junaid A. Khan ◽  
Michela Biancolella ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Expression Profile ◽  
Expression Profile ◽  
Knockout Mice ◽  
Cardiac Remodeling ◽  
Oxidant Stress ◽  
Reactive Oxygen Species Generation ◽  
Cardiac Response ◽  
Ang Ii ◽  
Wild Type

We studied the gene expression profile during cardiac hypertrophy induced by angiotensin (ANG) II in wild-type mice and the influence of LOX-1 deletion on the gene expression profile. Wild-type and LOX-1 knockout mice were given saline or ANG II infusion for 4 wk. The saline-treated LOX-1 knockout mice showed upregulation of several genes including Ddx3y and Eif2s3y. ANG II infusion enhanced expression of genes known to be associated with cardiac remodeling, such as Agt, Ace, Timp4, Fstl, and Tnfrst12a, as well as oxidant stress-related genes Gnaq, Sos1, and Rac1. Some other strongly upregulated genes identified in this study have not been previously associated with LOX-1 deletion and/or hypertension. To confirm these observations with ANG II infusion and LOX-1 deletion, cultured HL-1 mouse cardiomyocytes were exposed to ANG II or transfected with pCI-neo/LOX-1, which resulted in severalfold increase in reactive oxygen species generation, upregulation of ANG II type 1 (AT1) receptor, and cardiomyocyte growth. Quantitative PCR analysis of these treated cardiomyocytes confirmed upregulation of many of the genes identified in the in vivo study. This study provides the first set of data on the gene expression profiling of cardiac tissue treated with ANG II and expands on the important role of LOX-1 in cardiac response to ANG II.

Cellular glutathione peroxidase deficiency and endothelial dysfunction

2002 ◽  
Vol 282 (4) ◽  
pp. H1255-H1261 ◽  
Author(s):  
Marc A. Forgione ◽  
Norbert Weiss ◽  
Stanley Heydrick ◽  
André Cap ◽  
Elizabeth S. Klings ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Glutathione Peroxidase ◽  
Vascular Function ◽  
Vascular Reactivity ◽  
Oxidant Stress ◽  
Vascular Lesions ◽  
Wild Type ◽  
Vascular Abnormalities ◽  
Peroxidase Deficiency ◽  
Dose Dependent

Cellular glutathione peroxidase (GPx-1) is the most abundant intracellular isoform of the GPx antioxidant enzyme family. In this study, we hypothesized that GPx-1 deficiency directly induces an increase in vascular oxidant stress, with resulting endothelial dysfunction. We studied vascular function in a murine model of homozygous deficiency of GPx-1 (GPx-1−/−). Mesenteric arterioles of GPx-1−/− mice demonstrated paradoxical vasoconstriction to β-methacholine and bradykinin, whereas wild-type (WT) mice showed dose-dependent vasodilation in response to both agonists. One week of treatment of GPx-1−/− mice withl-2-oxothiazolidine-4-carboxylic acid (OTC), which increases intracellular thiol pools, resulted in restoration of normal vascular reactivity in the mesenteric bed of GPx-1−/−mice. We observed an increase of the isoprostane iPF2α-III, a marker of oxidant stress, in the plasma and aortas of GPx-1−/− mice compared with WT mice, which returned toward normal after OTC treatment. Aortic sections from GPx-1−/− mice showed increased binding of an anti-3-nitrotyrosine antibody in the absence of frank vascular lesions. These findings demonstrate that homozygous deficiency of GPx-1 leads to impaired endothelium-dependent vasodilator function presumably due to a decrease in bioavailable nitric oxide and to increased vascular oxidant stress. These vascular abnormalities can be attenuated by increasing bioavailable intracellular thiol pools.

scholarly journals Protective effect of extracellular superoxide dismutase on endothelial function during aging

2009 ◽  
Vol 296 (6) ◽  
pp. H1920-H1925 ◽  
Author(s):  
Donald D. Lund ◽  
Yi Chu ◽  
Jordan D. Miller ◽  
Donald D. Heistad
Keyword(s):  
Superoxide Dismutase ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Ex Vivo ◽  
Vascular Dysfunction ◽  
Extracellular Superoxide Dismutase ◽  
Mrna Levels ◽  
Wild Type ◽  
Vasomotor Function ◽  
Old Mice

Endothelial vasomotor function decreases with increasing age. Extracellular superoxide dismutase (ecSOD) protects against vascular dysfunction in several disease states. The purpose of this study was to determine whether endogenous ecSOD protects against endothelial dysfunction in old mice. Vasomotor function of the aorta was studied ex vivo in wild-type (ecSOD+/+) and ecSOD-deficient (ecSOD−/−) mice at 11 (adult) and 29 (old) mo of age. Maximal relaxation to acetylcholine (10−4 M) was impaired in vessels from adult ecSOD−/− mice [75 ± 3% (mean ± SE)] compared with wild-type mice (89 ± 2%, P < 0.05). Maximal relaxation to acetylcholine (10−4 M) was profoundly impaired in aorta from old ecSOD−/− mice (45 ± 5%) compared with wild-type mice (75 ± 4%, P < 0.05). There was a significant correlation between expression of ecSOD and maximal relaxation to acetylcholine in adult and old mice. Tempol (1 mM), a scavenger of superoxide, improved relaxation in response to acetylcholine (63 ± 8%) in old ecSOD−/− mice ( P < 0.05), but not wild-type mice (75 ± 4%). Maximal relaxation to sodium nitroprusside was similar in aorta from adult and old wild-type and ecSOD−/− mice. Quantitative RT-PCR showed a decrease in mRNA levels of ecSOD and catalase in aorta of old mice and an increase in levels of TNFα and Nox-4 in aorta of old mice compared with adult mice. The findings support the hypothesis that impaired antioxidant mechanisms may contribute to cumulative increases in oxidative stress and impaired endothelial function in old mice. In conclusion, endogenous ecSOD plays an important role in protection against endothelial dysfunction during aging.

scholarly journals Role of oxidative stress and AT1 receptors in cerebral vascular dysfunction with aging

2009 ◽  
Vol 296 (6) ◽  
pp. H1914-H1919 ◽  
Author(s):  
Mary L. Modrick ◽  
Sean P. Didion ◽  
Curt D. Sigmund ◽  
Frank M. Faraci
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Vascular Dysfunction ◽  
Ang Ii ◽  
Wild Type ◽  
Very Old ◽  
Vascular Responses ◽  
Basilar Arteries ◽  
Old Mice ◽  
Cerebral Vascular

Vascular dysfunction occurs with aging. We hypothesized that oxidative stress and ANG II [acting via ANG II type 1 (AT1) receptors] promotes cerebral vascular dysfunction with aging. We studied young (5–6 mo), old (17–19 mo), and very old (23 ± 1 mo) mice. In basilar arteries in vitro, acetylcholine (an endothelium-dependent agonist) produced dilation in young wild-type mice that was reduced by ∼60 and 90% ( P < 0.05) in old and very old mice, respectively. Similar effects were seen using A23187, a second endothelium-dependent agonist. The vascular response to acetylcholine in very old mice was almost completely restored with tempol (a scavenger of superoxide) and partly restored by PJ34, an inhibitor of poly(ADP-ribose) polymerase (PARP). We used mice deficient in Mn-SOD (Mn-SOD+/−) to test whether this form of SOD protected during aging but found that age-induced endothelial dysfunction was not altered by Mn-SOD deficiency. Cerebral vascular responses were similar in young mice lacking AT1 receptors (AT1−/−) and wild-type mice. Vascular responses to acetylcholine and A23187 were reduced by ∼50% in old wild-type mice ( P < 0.05) but were normal in old AT1-deficient mice. Thus, aging produces marked endothelial dysfunction in the cerebral artery that is mediated by ROS, may involve the activation of PARP, but was not enhanced by Mn-SOD deficiency. Our findings suggest a novel and fundamental role for ANG II and AT1 receptors in age-induced vascular dysfunction.

scholarly journals Angiotensin II impairs endothelial function via tyrosine phosphorylation of the endothelial nitric oxide synthase

2009 ◽  
Vol 206 (13) ◽  
pp. 2889-2896 ◽  
Author(s):  
Annemarieke E. Loot ◽  
Judith G. Schreiber ◽  
Beate Fisslthaler ◽  
Ingrid Fleming
Keyword(s):  
Angiotensin Ii ◽  
Endothelial Dysfunction ◽  
Tyrosine Phosphorylation ◽  
Dominant Negative ◽  
No Production ◽  
Dependent Manner ◽  
Ang Ii ◽  
Wild Type ◽  
Tyrosine Kinase 2

Proline-rich tyrosine kinase 2 (PYK2) can be activated by angiotensin II (Ang II) and reactive oxygen species. We report that in endothelial cells, Ang II enhances the tyrosine phosphorylation of endothelial NO synthase (eNOS) in an AT1-, H2O2-, and PYK2-dependent manner. Low concentrations (1–100 µmol/liter) of H2O2 stimulated the phosphorylation of eNOS Tyr657 without affecting that of Ser1177, and attenuated basal and agonist-induced NO production. In isolated mouse aortae, 30 µmol/liter H2O2 induced phosphorylation of eNOS on Tyr657 and impaired acetylcholine-induced relaxation. Endothelial overexpression of a dominant-negative PYK2 mutant protected against H2O2-induced endothelial dysfunction. Correspondingly, carotid arteries from eNOS−/− mice overexpressing the nonphosphorylatable eNOS Y657F mutant were also protected against H2O2. In vivo, 3 wk of treatment with Ang II considerably increased levels of Tyr657-phosphorylated eNOS in the aortae of wild-type but not Nox2y/− mice, and this was again associated with a clear impairment in endothelium-dependent vasodilatation in the wild-type but not in the Nox2y/− mice. Collectively, endothelial PYK2 activation by Ang II and H2O2 causes the phosphorylation of eNOS on Tyr657, attenuating NO production and endothelium-dependent vasodilatation. This mechanism may contribute to the endothelial dysfunction observed in cardiovascular diseases associated with increased activity of the renin–angiotensin system and elevated redox stress.

Effects of the Superoxide Dismutase-Mimic Compound TEMPOL on Oxidant Stress-Mediated Endothelial Dysfunction

1999 ◽  
Vol 1 (2) ◽  
pp. 221-232 ◽  
Author(s):  
Abdullah I. Haj-Yehia ◽  
Taher Nassar ◽  
Peter Assaf ◽  
Hisham Nassar ◽  
Erik E. Änggård
Keyword(s):  
Superoxide Dismutase ◽  
Endothelial Dysfunction ◽  
Oxidant Stress ◽  
Superoxide Dismutase Mimic

scholarly journals Activation of Nrf2 contributes to the protective effect of Exendin-4 against angiotensin II-induced vascular smooth muscle cell senescence

2016 ◽  
Vol 311 (4) ◽  
pp. C572-C582 ◽  
Author(s):  
Tengfei Zhou ◽  
Mengqian Zhang ◽  
Liang Zhao ◽  
Aiqin Li ◽  
Xiaomei Qin
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Vascular Smooth Muscle Cell ◽  
Binding Protein ◽  
Antioxidant Defenses ◽  
Heme Oxygenase 1 ◽  
Ang Ii

Oxidative stress and impaired antioxidant defense are believed to be contributors to the cardiovascular aging process. The transcription factor nuclear factor-E2-related factor 2 (Nrf2) plays a key role in orchestrating cellular antioxidant defenses and maintaining redox homeostasis. Our previous study showed that Exendin-4, a glucagon-like peptide-1 analog, alleviates angiotensin II (ANG II)-induced vascular smooth muscle cell (VSMC) senescence by inhibiting Rac1 activation via cAMP/PKA (Zhao L, Li AQ, Zhou TF, Zhang MQ, Qin XM. Am J Physiol Cell Physiol 307: C1130–C1141, 2014). The objective of this study is to investigate if Nrf2 mediates the antisenescent effect of Exendin-4 in ANG II-induced VSMCs. Here we report that Exendin-4 triggered Nrf2 nuclear translocation, a downstream target of cAMP-responsive element-binding protein (CREB) and expressions of antioxidant genes heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase-1 (NQO-1) in a dose- and time-dependent manner. In addition, knock-down of Nrf2 attenuated the inhibitory effects of Exendin-4 on ANG II-induced superoxidant generation and VSMC senescence. PKA/CREB pathway participated in the upregulations of HO-1 and NQO-1 induced by Exendin-4. Notably, our study revealed that Exendin-4 dose-dependently increased the acetylation of Nrf2 and the recruitment of transcriptional coactivator CREB binding protein (CBP) to Nrf2. The Exendin-4-induced Nrf2 transactivation was diminished in the presence of CBP small interfering RNA. Microscope imaging of Nrf2, as well as immunoblotting for Nrf2, showed that the Exendin-4-evoked Nrf2 acetylation favored its nuclear retention. Importantly, CBP silencing attenuated the suppressing effects of Exendin-4 on ANG II-induced VSMC senescence and superoxidant production. In conclusion, these results provide a mechanistic insight into how Nrf2 signaling mediates the antisenescent and antioxidative effects induced by Exendin-4 in VSMCs.

Abstract P618: Inactivation of Mitochondrial Deacetylase Sirt3 Promotes Vascular Oxidative Stress, Increases Endothelial Dysfunction and Exacerbates Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Anna E Dikalova ◽  
Roman Uzhachenko ◽  
Hana A Itani ◽  
David G Harrison ◽  
Sergey Dikalov
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Endothelial Dysfunction ◽  
Ex Vivo ◽  
Fold Increase ◽  
Organ Damage ◽  
Ang Ii ◽  
Wild Type ◽  
Vascular Oxidative Stress

Endothelial dysfunction is associated with aging, diabetes, hyperlipidemia, obesity and these risk factors affect the expression and activity of the mitochondrial deacetylase Sirt3. Sirt3 activates major antioxidant SOD2 by deacetylation of specific lysine residues and Sirt3 depletion increases oxidative stress. We hypothesized that loss of vascular Sirt3 increases endothelial dysfunction, promotes hypertension and end organ damage. The role of vascular Sirt3 was studied in wild-type C57Bl/6J mice and tamoxifen-inducible smooth muscle specific Sirt3 knockout mice (Smc Sirt3 KO ) using angiotensin II model of hypertension (Ang II, 0.7 mg/kg/day). Western blot showed 30% reduction of vascular Sirt3 and 2-fold increase in SOD2 acetylation in Ang II-infused WT mice. We have tested if ex vivo treatment of aorta with Sirt3 activator resveratrol improves endothelial function. Indeed, ex vivo incubation with resveratrol (10 μM) significantly reduced SOD2 acetylation, diminished mitochondrial O 2 and increased endothelial NO to normal level while Sirt3-inactive analog dihydroresveratrol had no effect. Specific role of vascular Sirt3 was studied in Smc Sirt3 KO mice by crossing floxed Sirt3 mice with mice carrying gene for inducible cre in the vascular smooth muscle. Sirt3 deletion exacerbates hypertension (165 mm Hg vs 155 mm Hg in wild-type) and significantly increases mortality in Ang II-infused Smc Sirt3 KO mice (60% vs 10% in wild-type) associated with severe edema and aortic aneurysm (100% vs 20% in wild-type). Decrease of NO is a hallmark of endothelial dysfunction in hypertension due to vascular oxidative stress. Indeed, Ang II infusion increased vascular O 2 by 2-fold and reduced endothelial NO by 2-fold. Interestingly, Ang II infusion in Smc Sirt3 KO mice caused severe vascular oxidative stress (3-fold increase in O 2 ) and exacerbated endothelial dysfunction (4-fold decrease in NO). These data indicate that reduced vascular Sirt3 activity occurs in hypertension and this promotes vascular oxidative stress, increases endothelial dysfunction, exacerbates hypertension, increases end-organ-damage and mortality. It is conceivable that Sirt3 agonists and SOD2 mimetics may have therapeutic potential in cardiovascular disease.

scholarly journals Role of Nox isoforms in angiotensin II-induced oxidative stress and endothelial dysfunction in brain

2012 ◽  
Vol 113 (2) ◽  
pp. 184-191 ◽  
Author(s):  
Sophocles Chrissobolis ◽  
Botond Banfi ◽  
Christopher G. Sobey ◽  
Frank M. Faraci
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Endothelial Dysfunction ◽  
Minor Role ◽  
Oxygen Species ◽  
Ang Ii ◽  
Wild Type ◽  
Vascular Beds ◽  
A Minor

Angiotensin II (Ang II) promotes vascular disease through several mechanisms including by producing oxidative stress and endothelial dysfunction. Although multiple potential sources of reactive oxygen species exist, the relative importance of each is unclear, particularly in individual vascular beds. In these experiments, we examined the role of NADPH oxidase (Nox1 and Nox2) in Ang II-induced endothelial dysfunction in the cerebral circulation. Treatment with Ang II (1.4 mg·kg−1·day−1 for 7 days), but not vehicle, increased blood pressure in all groups. In wild-type (WT; C57Bl/6) mice, Ang II reduced dilation of the basilar artery to the endothelium-dependent agonist acetylcholine compared with vehicle but had no effect on responses in Nox2-deficient (Nox2−/y) mice. Ang II impaired responses to acetylcholine in Nox1 WT (Nox1+/y) and caused a small reduction in responses to acetylcholine in Nox1-deficient (Nox1−/y) mice. Ang II did not impair responses to the endothelium-independent agonists nitroprusside or papaverine in either group. In WT mice, Ang II increased basal and phorbol-dibutyrate-stimulated superoxide production in the cerebrovasculature, and these increases were abolished in Nox2−/y mice. Overall, these data suggest that Nox2 plays a relatively prominent role in mediating Ang II-induced oxidative stress and cerebral endothelial dysfunction, with a minor role for Nox1.

Sign in / Sign up

Export Citation Format

Share Document