scholarly journals Na/H Exchange Regulatory Factor 1 Deficient Mice Show Evidence of Oxidative Stress and Altered Cisplatin Pharmacokinetics

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1036
Author(s):  
Adrienne M. Bushau-Sprinkle ◽  
Michelle T. Barati ◽  
Yuxuan Zheng ◽  
Walter H. Watson ◽  
Kenneth B. Gagnon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Kidney Injury ◽  
Kidney Cortex ◽  
Transferase Activity ◽  
Wild Type ◽  
Regulatory Factor ◽  
Renal Metabolism ◽  
Knock Out ◽  
Show Evidence ◽  
Glutamyl Transferase

(1) Background: One third of patients who receive cisplatin develop an acute kidney injury. We previously demonstrated the Na/H Exchange Regulatory Factor 1 (NHERF1) loss resulted in increased kidney enzyme activity of the pentose phosphate pathway and was associated with more severe cisplatin nephrotoxicity. We hypothesized that changes in proximal tubule biochemical pathways associated with NHERF1 loss alters renal metabolism of cisplatin or response to cisplatin, resulting in exacerbated nephrotoxicity. (2) Methods: 2–4 month-old male wild-type and NHERF1 knock out littermate mice were treated with either vehicle or cisplatin (20 mg/kg dose IP), with samples taken at either 4, 24, or 72 h. Kidney injury was determined by urinary neutrophil gelatinase-associated lipocalin and histology. Glutathione metabolites were measured by HPLC and genes involved in glutathione synthesis were measured by qPCR. Kidney handling of cisplatin was assessed by a kidney cortex measurement of γ-glutamyl transferase activity, Western blot for γ-glutamyl transferase and cysteine S-conjugate beta lyase, and ICP-MS for platinum content. (3) Results: At 24 h knock out kidneys show evidence of greater tubular injury after cisplatin and exhibit a decreased reduced/oxidized glutathione ratio under baseline conditions in comparison to wild-type. KO kidneys fail to show an increase in γ-glutamyl transferase activity and experience a more rapid decline in tissue platinum when compared to wild-type. (4) Conclusions: Knock out kidneys show evidence of greater oxidative stress than wild-type accompanied by a greater degree of early injury in response to cisplatin. NHERF1 loss has no effect on the initial accumulation of cisplatin in the kidney cortex but is associated with an altered redox status which may alter the activity of enzymes involved in cisplatin metabolism.

Electrical properties of rabbit early distal convoluted tubule in primary culture

1989 ◽  
Vol 257 (2) ◽  
pp. F288-F299 ◽  
Author(s):  
J. Merot ◽  
M. Bidet ◽  
B. Gachot ◽  
S. Le Maout ◽  
N. Koechlin ◽  
...  
Keyword(s):  
Primary Culture ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Transferase Activity ◽  
Gamma Glutamyl Transferase ◽  
Transport Pathway ◽  
Apical Side ◽  
Transepithelial Voltage ◽  
Glutamyl Transferase ◽  
Convoluted Tubules

Distal bright convoluted tubules (DCTb) were microdissected from rabbit kidney cortex and cultured in a hormonally defined medium. The quality and the degree of polarization of the growing epithelia were assessed by indirect immunofluorescence studies using a monoclonal antibody raised against the apical membrane of the DCTb in situ. The cultured monolayers had a high hexokinase activity and a low gamma-glutamyl transferase activity compared with cultured proximal convoluted tubules. Adenosine 3',5'-cyclic monophosphate production was stimulated by calcitonin and insensitive to parathyroid hormone, vasopressin, and isoproterenol. Both 20- and 30-day-old cultures developed an apical-negative transepithelial potential of -3.1 and -22.3 mV, respectively. Amiloride reversibly reduced the voltage by 90% only when applied on the apical side of the monolayers. Phenamil (10(-8), 10(-6) M) had the same effect as amiloride. Calcitonin reversibly decreased the transepithelial voltage. These data support the hypothesis that, in the DCTb in primary culture, the transepithelial voltage is due to the presence of Na channels and that calcitonin modulates this transport pathway.

Association of mitochondrial SOD deficiency with salt-sensitive hypertension and accelerated renal senescence

2007 ◽  
Vol 102 (1) ◽  
pp. 255-260 ◽  
Author(s):  
Bernardo Rodriguez-Iturbe ◽  
Lili Sepassi ◽  
Yasmir Quiroz ◽  
Zhenmin Ni ◽  
Nosratola D. Vaziri
Keyword(s):  
Oxidative Stress ◽  
Glomerular Sclerosis ◽  
Tubular Damage ◽  
Wild Type ◽  
Mitochondrial Superoxide ◽  
Show Evidence ◽  
Blood Pressures ◽  
Renal Senescence ◽  
Salt Sensitive Hypertension

Mitochondria are the major source of superoxide (O2−) in the aerobic organisms. O2− produced by the mitochondria is converted to hydrogen peroxide by mitochondrial superoxide dismutase (SOD2). Mice with complete SOD2 deficiency (SOD2−/−) exhibit dilated cardiomyopathy and fatty liver leading to neonatal mortality, whereas mice with partial SOD2 deficiency (SOD2+/−) show evidence of O2−-induced mitochondrial damage resembling cell senescence. Since earlier studies have provided compelling evidence for the role of oxidative stress and tubulointerstitial inflammation in the pathogenesis of hypertension, we tested the hypothesis that partial SOD2 deficiency may result in hypertension. Wild-type (SOD2+/+) and partial SOD2-deficient (SOD2+/−) mice had similar blood pressures at 6–7 mo of age, but at 2 yr SOD2+/− mice had higher blood pressure. Oxidative stress, renal interstitial T-cell and macrophage infiltration, tubular damage, and glomerular sclerosis were all significantly increased in 2-yr-old SOD2+/− mice. High-salt diet induced hypertension in 6-mo-old SOD2-deficient mice but not in wild-type mice. In conclusion, partial SOD2 deficiency results in oxidative stress and renal interstitial inflammation, changes compatible with accelerated renal senescence and salt-sensitive hypertension. These findings are consistent with the pattern described in numerous other models of salt-sensitive hypertension and resemble that commonly seen in elderly humans.

scholarly journals Analysis of the oxidative stress regulon identifies soxS as a genetic target for resistance reversal in multi-drug resistant Klebsiella pneumoniae

2020 ◽  
Author(s):  
João Anes ◽  
Katherine Dever ◽  
Athmanya Eshwar ◽  
Scott Nguyen ◽  
Yu Cao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Klebsiella Pneumoniae ◽  
Efflux Pump ◽  
Similar Data ◽  
Drug Resistant ◽  
Rna Seq ◽  
Wild Type ◽  
Knock Out ◽  
Global Regulators

AbstractIn bacteria, the defense system deployd to counter oxidative stress is orchestrated by three transcriptional factors – SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data is not available for Klebsiella pneumoniae. To address this data gap, oxidative stress was artificially induced in K. pneumoniae MGH 78578 using paraquat and the corresponding oxidative stress regulon recorded using RNA-seq. The soxS gene was significantly induced during oxidative stress and a knock-out mutant was constructed, to explore its functionality. The wild-type and mutant were grown in the presence of paraquat and subjected to RNA-seq to elucidate the soxS regulon in K. pneumoniae MGH78578. Genes that are commonly regulated both in the oxidative stress regulon and soxS regulon were identified and denoted as the ‘oxidative SoxS regulon’ – these included a stringent group of genes specifically regulated by SoxS. Efflux pump encoding genes such as acrAB-tolC, acrE, and global regulators such as marRAB were identified as part of this regulon. Consequently, the isogenic soxS mutant was found to exhibit a reduction in the minimum bactericidal concentration against tetracycline compared to that of the wild type. Impaired efflux activity, allowing tetracycline to be accumulated in the cytoplasm to bactericidal levels, was further evaluated using a tetraphenylphosphonium (TPP+) accumulation assay. The soxS mutant was also susceptible to tetracycline in vivo, in a zebrafish embryo model. We conclude that the soxS gene could be considered as a genetic target against which an inhibitor could be developed in the future and used in combinatorial therapy with tetracycline to combat infections associated with multi-drug resistant K. pneumoniae.

Deletion of Myeloid Interferon Regulatory Factor 4 (Irf4) in Mouse Model Protects against Kidney Fibrosis after Ischemic Injury by Decreased Macrophage Recruitment and Activation

2021 ◽  
pp. ASN.2020071010
Author(s):  
Kensuke Sasaki ◽  
Andrew S. Terker ◽  
Yu Pan ◽  
Zhilian Li ◽  
Shirong Cao ◽  
...  
Keyword(s):  
Renal Fibrosis ◽  
Macrophage Polarization ◽  
Kidney Injury ◽  
Significant Inhibition ◽  
Macrophage Infiltration ◽  
Wild Type ◽  
Regulatory Factor ◽  
Macrophage Cell ◽  
Kidney Fibrosis ◽  
M2 Phenotype

BackgroundAKI is characterized by abrupt and reversible kidney dysfunction, and incomplete recovery leads to chronic kidney injury. Previous studies by us and others have indicated that macrophage infiltration and polarization play key roles in recovery from AKI. The role in AKI recovery played by IFN regulatory factor 4 (IRF4), a mediator of polarization of macrophages to the M2 phenotype, is unclear.MethodsWe used mice with myeloid or macrophage cell–specific deletion of Irf4 (MΦ Irf4−/−) to evaluate Irf4’s role in renal macrophage polarization and development of fibrosis after severe AKI.ResultsSurprisingly, although macrophage Irf4 deletion had a minimal effect on early renal functional recovery from AKI, it resulted in decreased renal fibrosis 4 weeks after severe AKI, in association with less-activated macrophages. Macrophage Irf4 deletion also protected against renal fibrosis in unilateral ureteral obstruction. Bone marrow–derived monocytes (BMDMs) from MΦ Irf4−/− mice had diminished chemotactic responses to macrophage chemoattractants, with decreased activation of AKT and PI3 kinase and increased PTEN expression. PI3K and AKT inhibitors markedly decreased chemotaxis in wild-type BMDMs, and in a cultured macrophage cell line. There was significant inhibition of homing of labeled Irf4−/− BMDMs to postischemic kidneys. Renal macrophage infiltration in response to AKI was markedly decreased in MΦ Irf4−/− mice or in wild-type mice with inhibition of AKT activity.ConclusionsDeletion of Irf4 from myeloid cells protected against development of tubulointerstitial fibrosis after severe ischemic renal injury in mice, due primarily to inhibition of AKT-mediated monocyte recruitment to the injured kidney and reduced activation and subsequent polarization into a profibrotic M2 phenotype.

Gamma glutamyl transferase activity is Independently associated with oxidative stress rather than SYNTAX score

2014 ◽  
Vol 75 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Hakan Uçar ◽  
Mustafa Gür ◽  
Mehmet Yavuz Gözükara ◽  
Gülhan Yüksel Kalkan ◽  
Ahmet Oytun Baykan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Syntax Score ◽  
Transferase Activity ◽  
Gamma Glutamyl Transferase ◽  
Gamma Glutamyl ◽  
Glutamyl Transferase

scholarly journals Old Yellow Enzymes, Highly Homologous FMN Oxidoreductases with Modulating Roles in Oxidative Stress and Programmed Cell Death in Yeast

2007 ◽  
Vol 282 (49) ◽  
pp. 36010-36023 ◽  
Author(s):  
Osama Odat ◽  
Samer Matta ◽  
Hadi Khalil ◽  
Sotirios C. Kampranis ◽  
Raymond Pfau ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Antioxidant Activities ◽  
Ros Generation ◽  
Oxidized Glutathione ◽  
Wild Type ◽  
Antioxidant Genes ◽  
Knock Out ◽  
Chronological Aging

In a genetic screen to identify modifiers of Bax-dependent lethality in yeast, the C terminus of OYE2 was isolated based on its capacity to restore sensitivity to a Bax-resistant yeast mutant strain. Overexpression of full-length OYE2 suppresses Bax lethality in yeast, lowers endogenous reactive oxygen species (ROS), increases resistance to H2O2-induced programmed cell death (PCD), and significantly lowers ROS levels generated by organic prooxidants. Reciprocally, Δoye2 yeast strains are sensitive to prooxidant-induced PCD. Overexpression and knock-out analysis indicate these OYE2 antioxidant activities are opposed by OYE3, a highly homologous heterodimerizing protein, which functions as a prooxidant promoting H2O2-induced PCD in wild type yeast. To exert its effect OYE3 requires the presence of OYE2. Deletion of the 12 C-terminal amino acids and catalytic inactivation of OYE2 by a Y197F mutation enhance significantly survival upon H2O2-induced PCD in wild type cells, but accelerate PCD in Δoye3 cells, implicating the oye2p-oye3p heterodimer for promoting cell death upon oxidative stress. Unexpectedly, a strain with a double knock-out of these genes (Δoye2 oye3) is highly resistant to H2O2-induced PCD, exhibits increased respiratory capacity, and undergoes less cell death during the adaptive response in chronological aging. Simultaneous deletion of OYE2 and other antioxidant genes hyperinduces endogenous levels of ROS, promoting H2O2-induced cell death: in Δoye2 glr1 yeast high levels of oxidized glutathione elicited gross morphological aberrations involving the actin cytoskeleton and defects in organelle partitioning. Altering the ratio of reduced to oxidized glutathione by exogenous addition of GSH fully reversed these alterations. Based on this work, OYE proteins are firmly placed in the signaling network connecting ROS generation, PCD modulation, and cytoskeletal dynamics in yeast.

P0525ROLE OF NADPH OXIDASE 4 IN ACUTE KIDNEY INJURY ASSOCIATED TO MASSIVE INTRAVASCULAR HEMOLYSIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Cristina García Caballero ◽  
Melania Guerrero Hue ◽  
Alejandra Palomino Antolín ◽  
Matilde Cabanillas ◽  
Cristina Vazquez Carballo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Acute Kidney Injury ◽  
Renal Function ◽  
Renal Damage ◽  
Kidney Injury ◽  
Tubular Injury ◽  
Wild Type ◽  
Intravascular Hemolysis ◽  
Nadph Oxidase 4

Abstract Background and Aims Massive intravascular hemolysis is a common condition of several pathologies. It is associated with acute kidney injury (AKI) and progressive impairment of renal function. In this context, free hemoglobin (Hb) can exert harmful effects by accumulating in the kidney, where induces oxidative stress and it becomes cytotoxic. NADPH oxidase 4 (Nox4) is the principal source of reactive oxygen species (ROS) in the kidney. Nox4 is mostly expressed in proximal tubular cells with lower levels in glomerulus. The role of Nox4 in renal damage is not clear, with studies reporting beneficial or deleterious actions depending of the environmental conditions. For that reason we aimed to investigate the role of Nox4 in massive intravascular hemolysis-associated AKI. Method To study the role of Nox4 in AKI caused by massive intravascular hemolysis, we performed an experimental model of intravascular hemolysis by intraperitoneal injection of phenylhydrazine (200 mg/kg) in wild type (Nox4+/+) and Nox4 knockout mice (Nox4-/-). Mice were sacrificed 24 and 72 hours after intravascular hemolysis induction. We collected serum, urine and tissues sample. We analyzed renal function, oxidative stress, cell death and inflammation in these samples. In other experiments, wild type mice were treated with GKT137831 (10mg/kg/day), a potent Nox4 and Nox1 inhibitor, and mice were sacrificed 72h after induction of hemolysis. We also performed in vitro experiments in murine tubular epithelial cells (MCT) and murine podocytes cells to investigate the regulation of Nox4 in Hb-stimulated cells treated or not with GKT137831. Results Induction of intravascular hemolysis in Nox4+/+ mice increased creatinine and BUN levels and enhanced the expression of tubular injury markers, such as NGAL. These pathological effects were reduced in Nox4 knockout mice. Then, we analyzed oxidative stress in our experimental model thought determination of HO-1, ferritin, GSH and lipid peroxidation levels. All of these oxidative markers were reduced in Nox4-/- mice with intravascular hemolysis as compared with Nox4+/+ mice. We also observed that inflammatory markers such as IL-6, cell death and podocytes injury markers were reduced in Nox4-/- mice than in wild type mice, specially 72 hours after phenylhydrazine injection. In line with these results, GKT137831 administration ameliorated intravascular hemolysis-associated renal function impairment. Moreover, oxidative stress, tubular injury markers and podocyte injury were reduced in hemolytic mice treated with GKT137831. GKT137831 also reduced Hb- and heme-mediated oxidative stress in MCT and podocytes. Conclusion Our results show the important role of Nox4 in renal injury associated to massive intravascular hemolysis. Moreover, the inhibition of Nox4 may be a potential therapeutic target to prevent renal damage associated to Hb accumulation. These findings provide new insights into novel aspects of Hb-toxicity and may have important pathogenic and therapeutic implications for intravascular hemolysis related diseases

Contribution of PPARγ in modulation of acrolein-induced inflammatory signaling in gp91phox knock-out mice

2017 ◽  
Vol 95 (4) ◽  
pp. 482-490 ◽  
Author(s):  
Zivar Yousefipour ◽  
Neha Chug ◽  
Katarzyna Marek ◽  
Alicia Nesbary ◽  
Joseph Mathew ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Body Mass ◽  
Total Antioxidant Status ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor ◽  
Knock Out ◽  
Total Antioxidant ◽  
In The Wild ◽  
Knock Out Mice

Oxidative stress and inflammation are major contributors to acrolein toxicity. Peroxisome proliferator activated receptor gamma (PPARγ) has antioxidant and anti-inflammatory effects. We investigated the contribution of PPARγ ligand GW1929 to the attenuation of oxidative stress in acrolein-induced insult. Male gp91phox knock-out (KO) mice were treated with acrolein (0.5 mg·(kg body mass)–1 by intraperitoneal injection for 7 days) with or without GW1929 (GW; 0.5 mg·(kg body mass)–1·day–1, orally, for 10 days). The livers were processed for further analyses. Acrolein significantly increased 8-isoprostane and reduced PPARγ activity (P < 0.05) in the wild type (WT) and KO mice. GW1929 reduced 8-isoprostane (by 32% and 40% in WT and KO mice, respectively) and increased PPARγ activity (by 81% and 92% in WT and KO, respectively). Chemokine activity was increased (by 63%) in acrolein-treated WT mice, and was reduced by GW1929 (by 65%). KO mice exhibited higher xanthine oxidase (XO). Acrolein increased XO and COX in WT mice and XO in KO mice. GW1929 significantly reduced COX in WT and KO mice and reduced XO in KO mice. Acrolein significantly reduced the total antioxidant status in WT and KO mice (P < 0.05), which was improved by GW1929 (by 75% and 74%). The levels of NF-κB were higher in acrolein-treated WT mice. GW1929 reduced NF-κB levels (by 51%) in KO mice. Acrolein increased CD36 in KO mice (by 43%), which was blunted with GW1929. Data confirms that the generation of free radicals by acrolein is mainly through NAD(P)H, but other oxygenates play a role too. GW1929 may alleviate the toxicity of acrolein by attenuating NF-κB, COX, and CD36.

Glutamate and glutamine metabolism in tissues of developing lambs

1983 ◽  
Vol 101 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Jennifer M. Pell ◽  
Julia Tooley ◽  
Marjorie K. Jeacock ◽  
D. A. L. Shepherd
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Gradual Increase ◽  
Kidney Cortex ◽  
Transferase Activity ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Glutamyl Transferase ◽  
Glutaminase Activity

SUMMARYThe activities of glutamine synthetase, phosphate-dependent glutaminase, phosphate-independent glutaminase, glutamate dehydrogenase, γ-glutamyl transferase and glutamine-oxo-acid aminotransferase were assayed in liver, kidney cortex, brain (cerebral hemispheres), spleen, skeletal muscle and ileum obtained from lambs of 100–260 days conceptual age. A curve was fitted to each set of data relating enzyme activity and conceptual age.In the ileum, glutaminase and γ-glutamyl transferase activities declined during development. Glutamine synthetase activity in the spleen increased markedly after birth, whereas glutamate dehydrogenase activity declined as rumen function was established. In the liver, glutamate dehydrogenase and glutamine synthetase activities were highest in suckling lambs and there was a gradual increase in hepatic γ-glutamyl transferase activity throughout the period studied. The activity of phosphate-dependent glutaminase was lowest in the kidney cortex of ruminating lambs but renal activities of glutamate dehydrogenase, phosphate-independent glutaminase, glutamine synthetase and γ-glutamyl transferase were highest in ruminating lambs. In skeletal muscle, a gradual increase in glutamine synthetase activity occurred after 180 days conceptual age, whereas there was no detectable glutaminase activity in ruminating lambs. In the brain, there was an increase in glutamate dehydrogenase, phosphatedependent glutaminase and glutamine synthetase activities during the foetal and early suckling periods, whereas γ-glutamyl transferase activity increased throughout the period studied.Glutamine-oxo-acid aminotransferase activity was not detected in any of the tissues studied. Phosphate-independent glutaminase activity was always less than 10% of phosphate-dependent glutaminase activity and therefore must have a minor role in the metabolism of glutamine in lambs.A consideration of the relative activities of the enzymes at different stages of development indicated that the ileum, spleen, liver, kidney cortex and brain have a substantial potential for glutamine utilization during foetal life. As a lamb matures after birth, there are changes in the metabolism of glutamate and glutamine which indicate that there is a greater potential for net glutamine synthesis in older lambs. This could be associated with the need for detoxification of ammonia in ruminating lambs.

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