scholarly journals Differential activation of RAGE by HMGB1 modulates neutrophil-associated NADPH oxidase activity and bacterial killing

2012 ◽  
Vol 302 (1) ◽  
pp. C249-C256 ◽  
Author(s):  
Jean-Marc Tadié ◽  
Hong-Beom Bae ◽  
Sami Banerjee ◽  
Jaroslaw W. Zmijewski ◽  
Edward Abraham
Keyword(s):  
Nadph Oxidase ◽  
Intraperitoneal Injection ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
High Mobility ◽  
Bacterial Killing ◽  
E Coli ◽  
Glycation End Products ◽  
Nadph Oxidase Activation

The receptor for advanced glycation end products (RAGE) plays an important role in host defense against bacterial infection. In the present experiments, we investigated the mechanisms by which RAGE contributes to the ability of neutrophils to eradicate bacteria. Wild-type ( RAGE+/+) neutrophils demonstrated significantly greater ability to kill Eschericia coli compared with RAGE−/−neutrophils. After intraperitoneal injection of E. coli , increased numbers of bacteria were found in the peritoneal fluid from RAGE−/−as compared with RAGE+/+mice. Exposure of neutrophils to the protypical RAGE ligand AGE resulted in activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and enhanced killing of E. coli , and intraperitoneal injection of AGE enhanced bacterial clearance during peritonitis. However, incubation of neutrophils with high mobility group box 1 protein (HMGB1), which also binds to RAGE, diminished E. coli -induced activation of NADPH oxidase in neutrophils and bacterial killing both in vitro and in vivo. Deletion of the COOH-terminal tail of HMGB1, a region necessary for binding to RAGE, abrogated the ability of HMGB1 to inhibit bacterial killing. Incubation of neutrophils with HMGB1 diminished bacterial or AGE-dependent activation of NADPH oxidase. The increase in phosphorylation of the p40phoxsubunit of NADPH oxidase that occurred after culture of neutrophils with E. coli was inhibited by exposure of the cells to HMGB1. These results showing that HMGB1, through RAGE-dependent mechanisms, diminishes bacterial killing by neutrophils as well as NADPH oxidase activation provide a novel mechanism by which HMGB1 can potentiate sepsis-associated organ dysfunction and mortality.

scholarly journals Neutrophils from p40phox−/− mice exhibit severe defects in NADPH oxidase regulation and oxidant-dependent bacterial killing

2006 ◽  
Vol 203 (8) ◽  
pp. 1927-1937 ◽  
Author(s):  
Chris D. Ellson ◽  
Keith Davidson ◽  
G. John Ferguson ◽  
Rod O'Connor ◽  
Len R. Stephens ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Critical Role ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Phagocytic Cells ◽  
Bacterial Killing ◽  
Catalytic Core ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Factor Α

The generation of reactive oxygen species (ROS) by the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex plays a critical role in the antimicrobial functions of the phagocytic cells of the immune system. The catalytic core of this oxidase consists of a complex between gp91phox, p22phox, p47phox, p67phox, p40phox, and rac-2. Mutations in each of the phox components, except p40phox, have been described in cases of chronic granulomatous disease (CGD), defining their essential role in oxidase function. We sought to establish the role of p40phox by investigating the NADPH oxidase responses of neutrophils isolated from p40phox−/− mice. In the absence of p40phox, the expression of p67phox is reduced by ∼55% and oxidase responses to tumor necrosis factor α/fibrinogen, immunoglobulin G latex beads, Staphylococcus aureus, formyl-methionyl-leucyl-phenylalanine, and zymosan were reduced by ∼97, 85, 84, 75, and 30%, respectively. The defect in ROS production by p40phox−/− neutrophils in response to S. aureus translated into a severe, CGD-like defect in the killing of this organism both in vitro and in vivo, defining p40phox as an essential component in bacterial killing.

Cadmium Chloride Induces Memory Deficits and Hippocampal Damage by Activating the JNK/p66Shc/NADPH Oxidase Axis

2020 ◽  
Vol 39 (5) ◽  
pp. 477-490
Author(s):  
Attalla Farag El-kott ◽  
Ali S. Alshehri ◽  
Heba S. Khalifa ◽  
Abd-El-karim M. Abd-Lateif ◽  
Mohammad Ali Alshehri ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Cadmium Chloride ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Male Rats ◽  
Hippocampal Damage ◽  
Vitro Experiment ◽  
In Vitro Experiment ◽  
In Vivo Experiment

This study investigated whether the mechanism underlying the neurotoxic effects of cadmium chloride (CdCl2) in rats involves p66Shc. This study comprised an initial in vivo experiment followed by an in vitro experiment. For the in vivo experiment, male rats were orally administered saline (vehicle) or CdCl2 (0.05 mg/kg) for 30 days. Thereafter, spatial and retention memory of rats were tested and their hippocampi were used for biochemical and molecular analyses. For the in vitro experiment, control or p66Shc-deficient hippocampal cells were treated with CdCl2 (25 µM) in the presence or absence of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor. Cadmium chloride impaired the spatial learning and retention memory of rats; depleted levels of glutathione and manganese superoxide dismutase; increased reactive oxygen species (ROS), tumor necrosis factor α, and interleukin 6; and induced nuclear factor kappa B activation. Cadmium chloride also decreased the number of pyramidal cells in the CA1 region and induced severe damage to the mitochondria and endoplasmic reticulum of cells in the hippocampi of rats. Moreover, CdCl2 increased the total unphosphorylated p66Shc, phosphorylated (Ser36) p66Shc, phosphorylated JNK, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, cytochrome c, and cleaved caspase-3. A dose–response increase in cell death, ROS, DNA damage, p66Shc, and NADPH oxidase was also observed in cultured hippocampal cells treated with CdCl2. Of note, all of these biochemical changes were attenuated by silencing p66Shc or inhibiting JNK with SP600125. In conclusion, CdCl2 induces hippocampal ROS generation and apoptosis by promoting the JNK-mediated activation of p66Shc.

scholarly journals Once-daily gentamicin therapy for experimental Escherichia coli meningitis.

1997 ◽  
Vol 41 (1) ◽  
pp. 49-53 ◽  
Author(s):  
A Ahmed ◽  
M M París ◽  
M Trujillo ◽  
S M Hickey ◽  
L Wubbel ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Bacterial Killing ◽  
Once Daily ◽  
E Coli ◽  
Aminoglycoside Therapy ◽  
Gentamicin Concentration ◽  
Gentamicin Therapy ◽  
The Impact

In vitro and in vivo studies have demonstrated that the bacteriologic efficacy of once-daily aminoglycoside therapy is equivalent to that achieved with conventional multiple daily dosing. The impact of once-daily dosing for meningitis has not been studied. Using the well-characterized rabbit meningitis model, we compared two regimens of the same daily dosage of gentamicin given either once or in three divided doses for 24 or 72 h. The initial 1 h mean cerebrospinal fluid (CSF) gentamicin concentration for animals receiving a single dose (2.9 +/- 1.7 micrograms/ml) was threefold higher than that for the animals receiving multiple doses. The rate of bacterial killing in the first 8 h of treatment was significantly greater for the animals with higher concentrations in their CSF (-0.21 +/- 0.19 versus -0.03 +/- 0.22 log10 CFU/ml/h), suggesting concentration-dependent killing. By 24h, the mean reduction in bacterial titers was similar for the two regimens. In animals treated for 72 h, no differences in bactericidal activity was noted for 24, 48, or 72 h. Gentamicin at two different dosages was administered intracisternally to a separate set of animals to achieve considerably higher CSF gentamicin concentrations. In these animals, the rate of bacterial clearance in the first 8 h (0.52 +/- 0.15 and 0.58 +/- 0.15 log10 CFU/ml/h for the lower and higher dosages, respectively) was significantly greater than that in animals treated intravenously. In conclusion, there is evidence of concentration-dependent killing with gentamicin early in treatment for experimental E. coli meningitis, and once-daily dosing therapy appears to be at least as effective as multiple-dose therapy in reducing bacterial counts in CSF.

scholarly journals Dextromethorphan Reduces Oxidative Stress and Inhibits Uremic Artery Calcification

2021 ◽  
Vol 22 (22) ◽  
pp. 12277
Author(s):  
En-Shao Liu ◽  
Nai-Ching Chen ◽  
Tzu-Ming Jao ◽  
Chien-Liang Chen
Keyword(s):  
Oxidative Stress ◽  
Nadph Oxidase ◽  
Vascular Calcification ◽  
Wistar Rats ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Oxidase Inhibitor ◽  
In Vivo Studies ◽  
Ros Production

Medial vascular calcification has emerged as a key factor contributing to cardiovascular mortality in patients with chronic kidney disease (CKD). Vascular smooth muscle cells (VSMCs) with osteogenic transdifferentiation play a role in vascular calcification. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors reduce reactive oxygen species (ROS) production and calcified-medium–induced calcification of VSMCs. This study investigates the effects of dextromethorphan (DXM), an NADPH oxidase inhibitor, on vascular calcification. We used in vitro and in vivo studies to evaluate the effect of DXM on artery changes in the presence of hyperphosphatemia. The anti-vascular calcification effect of DXM was tested in adenine-fed Wistar rats. High-phosphate medium induced ROS production and calcification of VSMCs. DXM significantly attenuated the increase in ROS production, the decrease in ATP, and mitochondria membrane potential during the calcified-medium–induced VSMC calcification process (p < 0.05). The protective effect of DXM in calcified-medium–induced VSMC calcification was not further increased by NADPH oxidase inhibitors, indicating that NADPH oxidase mediates the effect of DXM. Furthermore, DXM decreased aortic calcification in Wistar rats with CKD. Our results suggest that treatment with DXM can attenuate vascular oxidative stress and ameliorate vascular calcification.

scholarly journals A novel pathway spatiotemporally activates Rac1 and redox signaling in response to fluid shear stress

2013 ◽  
Vol 201 (6) ◽  
pp. 863-873 ◽  
Author(s):  
Yunhao Liu ◽  
Caitlin Collins ◽  
William B. Kiosses ◽  
Ann M. Murray ◽  
Monika Joshi ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Molecular Mechanisms ◽  
Fluid Shear Stress ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Redox Signaling ◽  
Hemodynamic Forces ◽  
Rac1 Gtpase ◽  
Embryonic Organ

Hemodynamic forces regulate embryonic organ development, hematopoiesis, vascular remodeling, and atherogenesis. The mechanosensory stimulus of blood flow initiates a complex network of intracellular pathways, including activation of Rac1 GTPase, establishment of endothelial cell (EC) polarity, and redox signaling. The activity of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase can be modulated by the GTP/GDP state of Rac1; however, the molecular mechanisms of Rac1 activation by flow are poorly understood. Here, we identify a novel polarity complex that directs localized Rac1 activation required for downstream reactive oxygen species (ROS) production. Vav2 is required for Rac1 GTP loading, whereas, surprisingly, Tiam1 functions as an adaptor in a VE-cadherin–p67phox–Par3 polarity complex that directs localized activation of Rac1. Furthermore, loss of Tiam1 led to the disruption of redox signaling both in vitro and in vivo. Our results describe a novel molecular cascade that regulates redox signaling by the coordinated regulation of Rac1 and by linking components of the polarity complex to the NADPH oxidase.

scholarly journals Plant Extract of Limonium gmelinii Attenuates Oxidative Responses in Neurons, Astrocytes, and Cerebral Endothelial Cells In Vitro and Improves Motor Functions of Rats after Middle Cerebral Artery Occlusion

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1814
Author(s):  
Tulendy Nurkenov ◽  
Andrey Tsoy ◽  
Farkhad Olzhayev ◽  
Elvira Abzhanova ◽  
Anel Turgambayeva ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nadph Oxidase ◽  
Middle Cerebral Artery ◽  
Artery Occlusion ◽  
Ros Generation ◽  
Tnf Α ◽  
Cerebral Artery Occlusion ◽  
Nadph Oxidase Activation

There are numerous publications demonstrating that plant polyphenols can reduce oxidative stress and inflammatory processes in the brain. In the present study we have investigated the neuroprotective effect of plant extract isolated from the roots of L. gmelinii since it contains a rich source of polyphenols and other biologically active compounds. We have applied an oxidative and inflammatory model induced by NMDA, H2O2, and TNF-α in human primary neurons and astrocytes, and mouse cerebral endothelial cell (CECs) line in vitro. The levels of ROS generation, NADPH oxidase activation, P-selectin expression, and activity of ERK1/2 were evaluated by quantitative immunofluorescence analysis, confocal microscopy, and MAPK assay. In vivo, sensorimotor functions in rats with middle cerebral artery occlusion (MCAO) were assessed. In neurons NMDA induced overproduction of ROS, in astrocytes TNF-α initiated ROS generation, NADPH oxidase activation, and phosphorylation of ERK1/2. In CECs, the exposure by TNF-α induced oxidative stress and triggered the accumulation of P-selectin on the surface of the cells. In turn, pre-treatment of the cells with the extract of L. gmelinii suppressed oxidative stress in all cell types and pro-inflammatory responses in astrocytes and CECs. In vivo, the treatment with L. gmelinii extract improved motor activity in rats with MCAO.

P5506Proprotein convertase subtilisin/kexin 9 (PCSK9) and lipopolysaccharide (LPS) in patients with atrial fibrillation. A biomarker post-hoc analysis from the ATHERO-AF cohort

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
P Pignatelli Spinazzola ◽  
A Farcomeni ◽  
D Pastori ◽  
F Violi
Keyword(s):  
Atrial Fibrillation ◽  
Nadph Oxidase ◽  
Rank Test ◽  
Post Hoc Analysis ◽  
Increased Risk ◽  
Post Hoc ◽  
First Time ◽  
Nadph Oxidase Activation

Abstract Background Proprotein convertase subtilisin/kexin 9 (PCSK9) and lipopolysaccharides (LPS) are emerging as novel risk factors for cardiovascular events (CVEs). In vitro evidence suggested that PCSK9 production may be elicited by LPS via oxidative stress, However, their relationship in patients with atrial fibrillation (AF) has not been investigated. Methods Post-hoc analysis of a prospective, single centre cohort study of 907 patients with non-valvular AF. At baseline, PCSK9, LPS and NADPH oxidase (sNOX2-dp) were measured. We also assessed adherence to Mediterranean Diet (Med-Diet). PCSK9 and LPS were correlated to incidence of CVEs. Results At multivariate analysis, with PCSK9 above the median as dependent variable we found that high adherence to Med-Diet and antiplatelet drugs were inversely correlated to PCSK9 (odds ratio [OR] 0.737 95% Confidence interval [CI] 0.643–0.845 p=0.001 and OR 0.437 95% CI 0.219–0.871 p=0.017 respectively), while sNOX2-dp and LPS concentrations (OR 1.759 C.I. 95% 1.167–2.650, p=0.007 and OR 1.727 C.I. 95% 1.147–2.600 p=0.009 respectively) were directly correlated. In particular use of oil and wine were negatively associated to high PCSK9 levels (OR 0.376 95% CI 0.185–0.763, p=0.001 and OR 0.460 95% CI 0.289–0.733 p=0.007, respectively). Patients with concomitant high PCSK9 and LPS (highest tertile for both) had and increased risk of CVEs as compared to those with low levels (lowest tertile for both) with 48 and 29 CVEs in each group respectively (Log-Rank test, p=0.022) Conclusion This study demonstrated for the first time in vivo that circulating levels of PCSK9 are associated with high LPS concentration and NADPH oxidase activation. Concomitant increase of PCSK9 and LPS increased the risk of CVEs.

scholarly journals A SGLT2 Inhibitor Dapagliflozin Alleviates Diabetic Cardiomyopathy by Suppressing High Glucose-Induced Oxidative Stress in vivo and in vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu-jie Xing ◽  
Biao-hu Liu ◽  
Shu-jun Wan ◽  
Yi Cheng ◽  
Si-min Zhou ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nadph Oxidase ◽  
Diabetic Cardiomyopathy ◽  
High Glucose ◽  
Sglt2 Inhibitor ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
H9c2 Cells ◽  
Myocardial Oxidative Stress

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus (DM). One of the hallmarks of the DCM is enhanced oxidative stress in myocardium. The aim of this study was to research the underlying mechanisms involved in the effects of dapagliflozin (Dap) on myocardial oxidative stress both in streptozotocin-induced DCM rats and rat embryonic cardiac myoblasts H9C2 cells exposed to high glucose (33.0 mM). In in vivo studies, diabetic rats were given Dap (1 mg/ kg/ day) by gavage for eight weeks. Dap treatment obviously ameliorated cardiac dysfunction, and improved myocardial fibrosis, apoptosis and oxidase stress. In in vitro studies, Dap also attenuated the enhanced levels of reactive oxygen species and cell death in H9C2 cells incubated with high glucose. Mechanically, Dap administration remarkably reduced the expression of membrane-bound nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits gp91phox and p22phox, suppressed the p67phox subunit translocation to membrane, and decreased the compensatory elevated copper, zinc superoxide dismutase (Cu/Zn-SOD) protein expression and total SOD activity both in vivo and in vitro. Collectively, our results indicated that Dap protects cardiac myocytes from damage caused by hyperglycemia through suppressing NADPH oxidase-mediated oxidative stress.

scholarly journals Bactericidal Monoclonal Antibodies Specific to the Lipopolysaccharide O Antigen from Multidrug-Resistant Escherichia coli Clone ST131-O25b:H4 Elicit Protection in Mice

2015 ◽  
Vol 59 (6) ◽  
pp. 3109-3116 ◽  
Author(s):  
Valéria Szijártó ◽  
Luis M. Guachalla ◽  
Zehra C. Visram ◽  
Katharina Hartl ◽  
Cecília Varga ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibodies ◽  
Human Serum ◽  
Significant Proportion ◽  
Multidrug Resistant ◽  
Bacterial Killing ◽  
Content Type ◽  
E Coli

ABSTRACTTheEscherichia colisequence type 131 (ST131)-O25b:H4 clone has spread worldwide and become responsible for a significant proportion of multidrug-resistant extraintestinal infections. We generated humanized monoclonal antibodies (MAbs) that target the lipopolysaccharide O25b antigen conserved within this lineage. These MAbs bound to the surface of live bacterial cells irrespective of the capsular type expressed. In a serum bactericidal assayin vitro, MAbs induced >95% bacterial killing in the presence of human serum as the complement source. Protective efficacy at low antibody doses was observed in a murine model of bacteremia. The mode of actionin vivowas investigated by using aglycosylated derivatives of the protective MAbs. The significant binding to liveE. colicells and thein vitroandin vivoefficacy were corroborated in assays using bacteria grown in human serum to mimic relevant clinical conditions. Given the dry pipeline of novel antibiotics against multidrug-resistant Gram-negative pathogens, passive immunization with bactericidal antibodies offers a therapeutic alternative to control infections caused byE. coliST131-O25b:H4.

Sign in / Sign up

Export Citation Format

Share Document