scholarly journals Attenuation of renal excretory responses to ANG II during inhibition of superoxide dismutase in anesthetized rats

2010 ◽  
Vol 298 (2) ◽  
pp. F401-F407 ◽  
Author(s):  
Md. Abdul Hye Khan ◽  
Mohammed Toriqul Islam ◽  
Alexander Castillo ◽  
Dewan Syed Abdul Majid
Keyword(s):  
Superoxide Dismutase ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Ang Ii ◽  
Sod Activity ◽  
Doppler Flowmetry ◽  
Nadph Oxidase Activity ◽  
Blood Flows ◽  
Renal Responses

To examine the functional interaction between superoxide dismutase (SOD) and NADPH oxidase activity, we assessed renal responses to acute intra-arterial infusion of ANG II (0.5 ng·kg−1·min−1) before and during administration of a SOD inhibitor, diethyldithiocarbamate (DETC, 0.5 mg·kg−1·min−1), in enalaprilat-pretreated (33 μg·kg−1·min−1) rats ( n = 11). Total (RBF) and regional (cortical, CBF; medullary; MBF) renal blood flows were determined by Transonic and laser-Doppler flowmetry, respectively. Renal cortical and medullary tissue NADPH oxidase activity in vitro was determined using the lucigenin-chemiluminescence method. DETC treatment alone resulted in decreases in RBF, CBF, MBF, glomerular filtration rate (GFR), urine flow (V), and sodium excretion (UNaV) as reported previously. Before DETC, ANG II infusion decreased RBF (−18 ± 3%), CBF (−16 ± 3%), MBF [−5 ± 6%; P = not significant (NS)], GFR (−31 ± 4%), V (−34 ± 2%), and UNaV (−53 ± 3%). During DETC infusion, ANG II also caused similar reductions in RBF (−20 ± 4%), CBF (−19 ± 3%), MBF (−2 ± 2; P = NS), and in GFR (−22 ± 7%), whereas renal excretory responses (V; −12 ± 2%; UNaV; −24 ± 4%) were significantly attenuated compared with those before DETC. In in vitro experiments, ANG II (100 μM) enhanced NADPH oxidase activity both in cortical [13,194 ± 1,651 vs. 20,914 ± 2,769 relative light units (RLU)/mg protein] and in medullary (21,296 ± 2,244 vs. 30,597 ± 4,250 RLU/mg protein) tissue. Application of DETC (1 mM) reduced the basal levels and prevented ANG II-induced increases in NADPH oxidase activity in both tissues. These results demonstrate that renal excretory responses to acute ANG II administration are attenuated during SOD inhibition, which seems related to a downregulation of NADPH oxidase in the deficient condition of SOD activity.

Analysis of DHE-derived oxidation products by HPLC in the assessment of superoxide production and NADPH oxidase activity in vascular systems

2007 ◽  
Vol 292 (1) ◽  
pp. C413-C422 ◽  
Author(s):  
Denise C. Fernandes ◽  
João Wosniak ◽  
Luciana A. Pescatore ◽  
Maria A. Bertoline ◽  
Marcel Liberman ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Experimental Studies ◽  
Oxidation Products ◽  
Ang Ii ◽  
Specific Product ◽  
Nadph Oxidase Activity

Dihydroethidium (DHE) is a widely used sensitive superoxide (O2•−) probe. However, DHE oxidation yields at least two fluorescent products, 2-hydroxyethidium (EOH), known to be more specific for O2•−, and the less-specific product ethidium. We validated HPLC methods to allow quantification of DHE products in usual vascular experimental situations. Studies in vitro showed that xanthine/xanthine oxidase, and to a lesser degree peroxynitrite/carbon dioxide system led to EOH and ethidium formation. Peroxidase/H2O2 but not H2O2 alone yielded ethidium as the main product. In vascular smooth muscle cells incubated with ANG II (100 nM, 4 h), we showed a 60% increase in EOH/DHE ratio, prevented by PEG-SOD or SOD1 overexpression. We further validated a novel DHE-based NADPH oxidase assay in vascular smooth muscle cell membrane fractions, showing that EOH was uniquely increased after ANG II. This assay was also adapted to a fluorescence microplate reader, providing results in line with HPLC results. In injured artery slices, shown to exhibit increased DHE-derived fluorescence at microscopy, there was ∼1.5- to 2-fold increase in EOH/DHE and ethidium/DHE ratios after injury, and PEG-SOD inhibited only EOH formation. We found that the amount of ethidium product and EOH/ethidium ratios are influenced by factors such as cell density and ambient light. In addition, we indirectly disclosed potential roles of heme groups and peroxidase activity in ethidium generation. Thus HPLC analysis of DHE-derived oxidation products can improve assessment of O2•− production or NADPH oxidase activity in many vascular experimental studies.

scholarly journals Combination of Exercise Training and SOD Mimetic Tempol Enhances Upregulation of Nitric Oxide Synthase in the Kidney of Spontaneously Hypertensive Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Pengyu Cao ◽  
Osamu Ito ◽  
Daisuke Ito ◽  
Rong Rong ◽  
Yang Zheng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Exercise Training ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Sod Activity ◽  
Spontaneously Hypertensive ◽  
Nadph Oxidase Activity ◽  
Expression Levels

Both exercise training (Ex) and superoxide dismutase (SOD) mimetic tempol have antihypertensive and renal protective effects in rodent models of several hypertensions. We recently reported that Ex increases nitric oxide (NO) production and the expression levels of endothelial and neuronal NO synthase (eNOS and nNOS) in the kidney and aorta of the spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY). We also found that endogenous hydrogen peroxide (H2O2) upregulates the expression levels of eNOS and nNOS in SHR. To elucidate the mechanism of the Ex-upregulated NO system in the kidney, we examined the additive effect of Ex and tempol on the renal NO system in SHR and WKY. Our data showed that, in SHR, both Ex and tempol increase the levels of H2O2 and nitrate/nitrite (NOx) in plasma and urine. We also observed an increased renal NOS activity and upregulated expression levels of eNOS and nNOS with decreased NADPH oxidase activity. The effects of the combination of Ex and tempol on these variables were cumulate in SHR. On the other hand, we found that Ex increases these variables with increased renal NADPH oxidase activity, but tempol did not change these variables or affect the Ex-induced upregulation in the activity and expression of NOS in WKY. The SOD activity in the kidney and aorta was activated by tempol only in SHR, but not in WKY; whereas Ex increased SOD activity only in the aorta in both SHR and WKY. These results indicate that Ex-induced endogenous H2O2 produced in the blood vessel and other organs outside of the kidney may be carried to the kidney by blood flow and stimulates the NO system in the kidney.

Abstract 1380: Antioxidants Decrease Neuronal Angiotensin II Type 1 Receptor in Heart Failure: Inhibition of Activator Protein 1 and Jun N-Terminal Kinase

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Dongmei Liu ◽  
Lie Gao ◽  
Kurtis G Cornish ◽  
Irving H Zucker
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Neuronal Cell ◽  
Activator Protein 1 ◽  
Ang Ii ◽  
Nadph Oxidase Activity ◽  
Activator Protein

In a previous study, we showed that Ang II type I receptor (AT1R) expression increased in the rostral ventrolateral medulla (RVLM) of chronic heart failure (CHF) rabbits and in normal rabbits infused with intracerebroventricular (ICV) Angiotensin II (AngII). The present study investigated if oxidative stress plays a role in Ang II induced AT1R upregulation and its relationship to the transcription factor activator protein 1 (AP1) in CHF rabbits and in the CATHa neuronal cell line. In neuronal cell cultures, Ang II significantly increased AT1R mRNA by 153 ± 22%, P <0.01; c-Jun mRNA by 90 ± 10%, P < 0.01; NADPH oxidase activity by 126 ± 43%, P < 0.01 versus untreated cells; Tempol, Apocynin and the AP 1 inhibitor Tanshinone II reversed the increased AT1R, c-Jun expression and NADPH oxidase activity induced by AngII. We examined the effect of ICV Tempol on expression of these proteins in the RVLM of CHF rabbits. Compared to untreated CHF rabbits Tempol significantly decreased AT1R protein expression (0.88±0.16 vs. 1.6±0.29, P <0.05), phosphorylated Jnk protein (0.10±0.02 vs. 0.31±0.10, P <0.05), and phosphorylated c-Jun (0.02±0.001 vs. 0.14±0.05, P <0.05). These data suggest that Ang II induces AT1R upregulation at the transcriptional level by activation of oxidative stress and AP1 in both cultured cells and in intact brain. Antioxidant agents may be beneficial in CHF by decreasing AT1R expression through the Jnk and AP1 pathway.

scholarly journals Effect of renin inhibition and AT1R blockade on myocardial remodeling in the transgenic Ren2 rat

2008 ◽  
Vol 295 (1) ◽  
pp. E103-E109 ◽  
Author(s):  
Adam Whaley-Connell ◽  
Javad Habibi ◽  
Shawna A. Cooper ◽  
Vincent G. DeMarco ◽  
Melvin R. Hayden ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Myocardial Remodeling ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Nadph Oxidase Activity ◽  
Renin Inhibition

Angiotensin II (Ang II) stimulation of the Ang type 1 receptor (AT1R) facilitates myocardial remodeling through NADPH oxidase-mediated generation of oxidative stress. Components of the renin-angiotensin system constitute an autocrine/paracrine unit in the myocardium, including renin, which is the rate-limiting step in the generation of Ang II. This investigation sought to determine whether cardiac oxidative stress and cellular remodeling could be attenuated by in vivo renin inhibition and/or AT1R blockade in a rodent model of chronically elevated tissue Ang II levels, the transgenic (mRen2)27 rat (Ren2). The Ren2 overexpresses the mouse renin transgene with resultant hypertension, insulin resistance, and cardiovascular damage. Young (6- to 7-wk-old) heterozygous (+/−) male Ren2 and age-matched Sprague-Dawley rats were treated with the renin inhibitor aliskiren, which has high preferential affinity for human and mouse renin, an AT1R blocker, irbesartan, or placebo for 3 wk. Myocardial NADPH oxidase activity and immunostaining for NADPH oxidase subunits and 3-nitrotyrosine were evaluated and remodeling changes assessed by light and transmission electron microscopy. Blood pressure, myocardial NADPH oxidase activity and subunit immunostaining, 3-nitrotyrosine, perivascular fibrosis, mitochondrial content, and markers of activity were significantly increased in Ren2 compared with SD littermates. Both renin inhibition and blockade of the AT1R significantly attenuated cardiac functional and structural alterations, although irbesartan treatment resulted in greater reductions of both blood pressure and markers of oxidative stress. Collectively, these data suggest that both reduce changes driven, in part, by Ang II-mediated increases in NADPH oxidase and, in part, increases in blood pressure.

scholarly journals Renin Inhibition Attenuates Insulin Resistance, Oxidative Stress, and Pancreatic Remodeling in the Transgenic Ren2 Rat

Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5643-5653 ◽  
Author(s):  
Javad Habibi ◽  
Adam Whaley-Connell ◽  
Melvin R. Hayden ◽  
Vincent G. DeMarco ◽  
Rebecca Schneider ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Reactive Oxygen Species ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Renin Angiotensin System ◽  
Oxygen Species ◽  
Ang Ii ◽  
Angiotensin System ◽  
Nadph Oxidase Activity ◽  
Renin Inhibition

Emerging evidence indicates that pancreatic tissue expresses all components of the renin-angiotensin system. However, the functional role is not well understood. This investigation examined renin inhibition on pancreas structure/function in the transgenic Ren2 rat harboring the mouse renin gene, a model of tissue renin overexpression. Renin is the rate-limiting step in the generation of angiotensin II (Ang II), which stimulates the generation of reactive oxygen species in a variety of tissues. Overexpression of renin in Ren2 rats results in hypertension, insulin resistance, and cardiovascular and renal damage. Young (6–7 wk old) insulin-resistant male Ren2 and age-matched insulin sensitive Sprague Dawley rats were treated with the renin inhibitor, aliskiren (50 mg/kg·d by ip injection), or placebo for 21 d. At 21 d, the Ren2 demonstrated insulin resistance with increased islet insulin, Ang II, and reduced total insulin receptor substrate (IRS)-1, IRS-2, and Akt immunostaining. There was increased islet nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and subunits (p47phox and Rac1) as well as increased nitrotyrosine immunostaining (each P &lt; 0.05). These functional abnormalities were associated with a disordered islet architecture; increased islet-exocrine interface, pericapillary fibrosis, and structurally abnormal mitochondria and content in endocrine and exocrine pancreas. In vivo treatment with aliskiren normalized systemic insulin resistance and islet insulin, Ang II, NADPH oxidase activity/subunits, and nitrotyrosine and improved total IRS-1 and Akt phosphorylation (each P &lt; 0.05) as well as islet/exocrine structural abnormalities. Collectively, these data suggest that pancreatic functional/structural changes are driven, in part, by tissue renin-angiotensin system-mediated increases in NADPH oxidase and reactive oxygen species generation, abnormalities attenuated with direct renin inhibition.

scholarly journals The flavin monooxygenase Bs3 triggers cell death in plants, impairs growth in yeast and produces H2O2 in vitro

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256217
Author(s):  
Christina Krönauer ◽  
Thomas Lahaye
Keyword(s):  
Nadph Oxidase ◽  
Oxidation State ◽  
Transcriptional Activation ◽  
Oxidase Activity ◽  
Plant Immunity ◽  
Striking Similarity ◽  
In Planta ◽  
Nadph Oxidase Activity ◽  
Wide Range

The pepper resistance gene Bs3 triggers a hypersensitive response (HR) upon transcriptional activation by the corresponding effector protein AvrBs3 from the bacterial pathogen Xanthomonas. Expression of Bs3 in yeast inhibited proliferation, demonstrating that Bs3 function is not restricted to the plant kingdom. The Bs3 sequence shows striking similarity to flavin monooxygenases (FMOs), an FAD- and NADPH-containing enzyme class that is known for the oxygenation of a wide range of substrates and their potential to produce H2O2. Since H2O2 is a hallmark metabolite in plant immunity, we analyzed the role of H2O2 during Bs3 HR. We purified recombinant Bs3 protein from E. coli and confirmed the FMO function of Bs3 with FAD binding and NADPH oxidase activity in vitro. Translational fusion of Bs3 to the redox reporter roGFP2 indicated that the Bs3-dependent HR induces an increase of the intracellular oxidation state in planta. To test if the NADPH oxidation and putative H2O2 production of Bs3 is sufficient to induce HR, we adapted previous studies which have uncovered mutations in the NADPH binding site of FMOs that result in higher NADPH oxidase activity. In vitro studies demonstrated that recombinant Bs3S211A protein has twofold higher NADPH oxidase activity than wildtype Bs3. Translational fusions to roGFP2 showed that Bs3S211A also increased the intracellular oxidation state in planta. Interestingly, while the mutant derivative Bs3S211A had an increase in NADPH oxidase capacity, it did not trigger HR in planta, ultimately revealing that H2O2 produced by Bs3 on its own is not sufficient to trigger HR.

Effects of Gentiopicroside on Oxidative Stress and Apoptosis in Gastric Cancer Cells

2021 ◽  
Vol 11 (3) ◽  
pp. 553-559
Author(s):  
Xinyi Wu ◽  
Suying Li ◽  
Shuo An
Keyword(s):  
Oxidative Stress ◽  
Gastric Cancer ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Related Factor ◽  
Sod Activity ◽  
Nadph Oxidase Activity ◽  
Expression Levels ◽  
Apoptosis Rate ◽  
Mda Content

Gastric cancer (GC) cells were sorted into six groups: NC, different concentrations of gentiopi-croside, pcDNA-NC, pcDNA-Nrf2, pcDNA-NC + gentiopicroside, and pcDNA-Nrf2 + gentiopicroside. The detection and comparison of cell survival and apoptosis showed that the activity of GC cells decreased and the apoptosis rate increased after gentiopicroside treatment. Western blot detection was performed to determine the expression levels of proliferating cell nuclear antigen (PCNA), B-cell leukemia/lymphoma-2 (Bcl-2)-associated X protein (Bax), Bcl-2, Kelch-like epichlorohydrin-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). Kits were used to determine the malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. The MDA content, NADPH oxidase activity, and Keap1 and Bax expression levels increased, and the SOD activity and Bcl-2, PCNA, Nrf2, and ARE expression levels decreased. Nrf2 overexpression increased the cell activity, SOD activity, and Nrf2, ARE, PCNA, and Bcl-2 expression levels and reduced the apoptosis rate, MDA content, NADPH oxidase activity, and Bax and Keap1 expression levels. At the same time, Nrf2 overexpression reversed the effects of gentiopicroside on oxidative stress and apoptosis of GC cells. These results suggest that gentiopicroside probably promotes oxidative stress and apoptosis of GC cells by inhibiting the Keap1/Nrf2/ARE signaling pathway.

scholarly journals Polydatin prevents angiotensin II-induced cardiac hypertrophy and myocardial superoxide generation

2014 ◽  
Vol 240 (10) ◽  
pp. 1352-1361 ◽  
Author(s):  
Qi Zhang ◽  
Yingying Tan ◽  
Nan Zhang ◽  
Fanrong Yao
Keyword(s):  
Nadph Oxidase ◽  
Cardiac Hypertrophy ◽  
Oxidase Activity ◽  
Weight Ratio ◽  
Heart Weight ◽  
Leucine Incorporation ◽  
Dependent Manner ◽  
Ang Ii ◽  
Nadph Oxidase Activity ◽  
Cultured Cardiomyocytes

Our studies and others recently demonstrate that polydatin, a resveratrol glucoside, has antioxidative and cardioprotective effects. This study aims to investigate the direct effects of polydatin on Ang II-induced cardiac hypertrophy to explore the potential role of polydatin in cardioprotection. Our results showed that in primary cultured cardiomyocytes, polydatin blocked Ang II-induced cardiac hypertrophy in a dose-dependent manner, which were associated with reduction in the cell surface area and [3H]leucine incorporation, as well as attenuation of the mRNA expressions of atrial natriuretic factor and β-myosin heavy chain. Furthermore, polydatin prevented rat cardiac hypertrophy induced by Ang II infusion, as assessed by heart weight-to-body weight ratio, cross-sectional area of cardiomyocyte, and gene expression of hypertrophic markers. Further investigation demonstrated that polydatin attenuated the Ang II-induced increase in the reactive oxygen species levels and NADPH oxidase activity in vivo and in vitro. Polydatin also blocked the Ang II-stimulated increases of Nox4 and Nox2 expression in cultured cardiomyocytes and the hearts of Ang II-infused rats. Our results indicate that polydatin has the potential to protect against Ang II-mediated cardiac hypertrophy through suppression of NADPH oxidase activity and superoxide production. These observations may shed new light on the understanding of the cardioprotective effect of polydatin.

Abstract 612: ACE2-Independent Sex Differences In Oxidative Stress

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Jan Wysocki ◽  
Karla Evora ◽  
Moody Salem ◽  
Christoph Maier ◽  
Minghao Ye ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sex Differences ◽  
Nadph Oxidase ◽  
Total Protein ◽  
Oxidase Activity ◽  
Kidney Injury ◽  
Ang Ii ◽  
Male Mice ◽  
Nadph Oxidase Activity ◽  
Female Mice

Many of the pathophysiological effects of angiotensin II (Ang II) are attributed to its stimulation of NADPH oxidases and the consequent production of reactive oxygen species. Female sex has generally lower cardiovascular morbidity and is also less susceptible to kidney injury than males. The basis of these phenomena is not well understood but it is possible that sex-differential regulation of oxidative stress through activation of the RAS and its key effector, Ang II, plays an important contributor role. Here we hypothesized that Ang II levels are higher in male mice and that this is associated with sex-differences in kidney levels of ACE2, an Ang II-degrading enzyme abundantly expressed in the kidney. Parameters of oxidative stress such as, NADPH oxidase activity and malondialdehyde levels (MDA) were measured in kidneys from female and age-matched male C57BL6 mice. At 40 weeks of age, NADPH oxidase activity (p<0.01) and MDA levels (p<0.05) were significantly lower in female than in male mice. Female mice had lower kidney levels of the pro-oxidant peptide, Ang II (0.94±0.19 vs. 1.66±0.17 fmol/mg total protein, p<0.05, respectively). The difference in kidney Ang II levels between females and males was also observed in the face of complete ACE2 genetic deficiency (1.08±0.16 vs 1.97±0.25 fmol/mg total protein, p<0.05, respectively). Consistent with kidney Ang II levels, urinary Ang II levels measured in urines from female WT mice were also significantly lower than in male WT mice (23.6±2.2 vs. 47.9±8.8 pg/mg creatinine, p<0.05) despite significantly higher levels of urinary ACE2 activity in male mice as compared to female mice (7.0±0.5 vs. 3.6±0.3, p<0.01, respectively). Female mice have lower basal levels of kidney oxidative stress than males and exhibit lower levels of kidney and urinary Ang II. The mechanism involved in sex differences in the levels of kidney and urine Ang II does not appear to depend on ACE2.

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