T cells express a phagocyte-type NADPH oxidase that is activated after T cell receptor stimulation.

Downregulation of p22phox in Retinal Pigment Epithelial Cells Inhibits Choroidal Neovascularization in Mice

Relative contributions of mitochondria and NADPH oxidase to deoxycorticosterone acetate-salt hypertension in mice

Free-radical production and function in blood vessels

ABSTRACTObjectives Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of stroke worldwide. We adapted a rat model of atherosclerosis to study brain intracranial atherosclerosis, and further investigated how omega-3 fatty acids (O3FA) attenuated the development of ICAS by reducing the generation of reactive oxygen species (ROS) and the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity.Methods Adult male Sprague-Dawley rats were divided into control normal-cholesterol or high-cholesterol diet groups with or without O3FA for up to 6 weeks. NG-nitro-L-arginine methyl ester (L-NAME, 3 mg/mL), a nitric oxide synthase inhibitor, was added to the drinking water of the high-cholesterol groups during the first 2 weeks. The rats received supplementation with O3FA (5 mg/kg/day) by gavage. At 3 and 6 weeks, we measured blood lipid levels, including low-density lipoprotein (LDL), cholesterol (CHO), triglycerides (TG), and high-density lipoprotein (HDL) as atherosclerotic blood markers. The lumen of middle cerebral artery (MCA) and the thickness of the vessel wall were assessed histologically. ROS production was measured. NOX activity and mRNA and protein expression of NOX subunits (p47phox, gp91phox, p22phox, and p67phox) were measured.Results A high-cholesterol diet exhibited a significant increase in the classic blood markers (LDL, CHO, and TG) for atherosclerosis, as well as a decrease in HDL. These markers were found to be progressively more severe with time. Additionally, increased lumen stenosis and intimal thickening were observed in the MCA for this group. Rats given O3FA demonstrated attenuation of blood lipid levels with an absence of morphological changes.O3FA significantly reduced ROS production and NOX activity in the brain. Moreover, O3FA decreased the mRNA and protein expression of the NOX subunits p47phox, gp91phox, and p67phox.Conclusions Long-term O3FA dietary supplementation prevents the development of intracranial atherosclerosis. This O3FA effect appears to be mediated by its attenuation of NOX subunit expression and NOX activity, therefore reducing ROS production. O3FA dietary supplement shows promising results in the prevention of ICAS.

Background: Excess reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) promotes apoptotic cell death following ischemic/reperfusion injury. Effect of chlorpromazine and promethazine (C+P) on brain activity was reported to induce neuroprotection. The current study was designed to evaluate the inhibitory function of C+P on oxidative injury after stroke. Methods: Adult male Sprague-Dawley rats were subjected to 2 h middle cerebral artery occlusion (MCAO) followed by 6 or 24 h of reperfusion. At the onset of reperfusion, rats received C+P, or apocynin (NOX inhibitor), or rottlerin [protein kinase C (PKC) δ inhibitor]. Brain damage was evaluated using infarct volumes and neurological deficits as well as apoptotic cell death (TUNEL). The enzymatic activity of NOX and ROS production as well as protein expressions of NOX subunits (gp91 phox , p67 phox , p47 phox , and p22 phox ), phosphorylation of PKC δ (p-PKC δ)/PKC δ and manganese superoxide dismutase (MnSOD) was examined. Neural SHSY5Y cells were used under 2 h of oxygen-glucose deprivation (OGD) followed by reoxygenation for 6 and 24 h with or without C+P treatment. ROS and protein levels of NOX subunits, p-PKC δ/PKC δ and MnSOD were detected. Moreover, measurement of PKC δ membrane translocation and detection of the interaction of p47 phox and PKC δ through co-immunoprecipitation were performed. Results: C+P reduced cerebral infarct volumes, neurological deficits, and apoptotic cell death in the ischemic rats, as well observed in the presence of NOX and PKC δ inhibitors. ROS production, NOX activity, expression of NOX subunits, p-PKC δ/PKC δ and MnSOD were significantly reduced by C+P. In ischemic rats administered with NOX and PKC δ inhibitors, ROS, activity of NOX and the NOX subunits protein levels were all decreased. In the OGD/R model, C+P decreased ROS and protein levels of NOX subunits, p-PKC δ/PKC δ and MnSOD. Furthermore, C+P reduced the PKC δ membrane translocation and the interaction of p47 phox and PKC δ. Conclusion: C+P treatments confers neuroprotection in severe stroke by suppressing oxidative stress and ROS production. PKC δ/NOX/MnSOD may be the vital regulators and the potential targets for an efficacious therapy following ischemic stroke.

Stachydrine hydrochloride reduces NOX2 activity to suppress oxidative stress levels to improve cardiac insufficiency.

In high glucose protein kinase C-ζ activation is required for mesangial cell generation of reactive oxygen species

Apocyanin, a microglial NADPH oxidase inhibitor prevents dopaminergic neuronal degeneration in lipopolysaccharide induced Parkinson's disease model

The vascular endothelium plays an important role in the regulation of inflammatory responses after trauma and hemorrhage. Interactions of neutrophils with endothelial cells (ECs) contribute to the activation of specific EC responses involved in innate immunity. We have previously reported that oxidants derived from the neutrophil reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a critical regulator to EC activation. Our objective was to test the role of neutrophil NADPH oxidase-derived oxidants in mediating and enhancing hemorrhagic shock (HS)-induced activation of lung endothelial NADPH oxidase. Mice were subjected to HS and neutrophil depletion. The mice were also replenished with the neutrophil from NADPH oxidase-deficient mice. The resultant activation of lung NADPH oxidase was analyzed. The in vivo studies were also recapitulated with in vitro neutrophil-EC coculture system. HS induces NADPH oxidase activation in neutrophils and lung through high-mobility group box 1/Toll-like receptor 4-dependent signaling. In neutropenic mice, shock-induced NADPH oxidase activation in the lung was reduced significantly, but was restored upon repletion with neutrophils obtained from wild-type mice subjected to shock, but not with neutrophils from shock mice lacking the gp91(phox) subunit of NADPH oxidase. The findings were recapitulated in mouse lung vascular ECs cocultured with neutrophils. The data further demonstrate that neutrophil-derived oxidants are key factors mediating augmented High mobility group box 1 (HMGB1)-induced endothelial NADPH oxidase activation through a Rac1-dependent, but p38 mitogen-activated protein kinase-independent, pathway. Oxidant signaling by neutrophil NADPH oxidase is an important determinant of activation of endothelial NADPH oxidase after HS.

The production of reactive oxygen species in TLR-stimulated granulocytes is not enhanced by hyperglycemia in diabetes

Reactive oxygen species amplify protein kinase C signaling in high glucose-induced fibronectin expression by human peritoneal mesothelial cells

Alzheimer’s disease (AD) is one of the main human dementias around the world which is constantly increasing every year due to several factors (age, genetics, environment, etc.) and there are no prevention or treatment options to cure it. AD is characterized by memory loss associated with oxidative stress (OS) in brain cells (neurons, astrocytes, microglia, etc.). OS can be produced by amyloid beta (Aβ) protein aggregation and its interaction with metals, mitochondrial damage and alterations between antioxidants and oxidant enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. NADPH oxidase produces reactive oxygen species (ROS) and it is overexpressed in AD, producing large amounts of superoxide anions and hydrogen peroxide which damage brain cells and the vasculature. In addition, it has been reported that NADPH oxidase causes an imbalance of pH which could also influence in the amyloid beta (Aβ) production. Therefore, NADPH oxidase had been proposed as a therapeutic target in AD. However, there are no drugs for AD treatment such as an NADPH oxidase inhibitor despite great efforts made to stabilize the ROS production using antioxidant molecules. So, in this work, we will focus our attention on NADPH oxidase (NOX2 and NOX4) in AD as well as in AD models and later discuss the use of NADPH oxidase inhibitor compounds in AD.

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] A key risk factor for the development of atherosclerosis is familial hypercholesterolemia (FH), a genetic disease characterized by elevated levels of low density lipoprotein (LDL). Studies have shown that oxidative stress and vascular smooth muscle cell (VSMC) phenotypic modulation play critical roles in the development and stability of atherosclerotic plaques. The key source of reactive oxygen species (ROS) contributing to oxidative stress in the vasculature is the enzymatic complex nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Upregulation of intermediateconductance Ca[superscript 2 +]-activated K[superscript +] channels (K[subscript Ca]3.1) and modification of NADPH oxidase activity have been shown to mediate phenotypic modulation of coronary smooth muscle cells (CSMC). It remains unclear, however, whether K[subscript Ca]3.1 expression and activity are altered in atherosclerotic coronary smooth muscle of individuals with FH, and whether NADPH oxidase plays a role in atherosclerosis through regulation of K[subscript Ca]3.1 channels. Our objective was thus twofold, 1) to determine whether K[subscript Ca]3.1 expression and activity are increased in CSMCs isolated from FH swine, and 2) to determine if NADPH oxidase plays a role in growth factor-induced upregulation of K[subscript Ca]3.1. Right coronary artery (RCA) sections from 2 year old FH swine showed a [approximate sign]15 fold increase in artery stenosis accompanied by significantly elevated triglyceride and cholesterol values. In the media of the diseased FH coronaries, there was a trend for increased K[subscript Ca]3.1mRNA expression and K[subscript Ca]3.1 protein expression was elevated [approximate sign]20% compared to control coronaries. In addition, K[subscript Ca]3.1 channel activity increased almost 2- fold in coronary artery cells isolated from FH swine compared to control animals. In cultured CSMCs, basic fibroblast growth factor (bFGF) increased superoxide (O[subscript 2] [superscript .-]) production which was inhibited by treatment with the NADPH oxidase inhibitor apocynin (Apo). Treatment with bFGF increased K[subscript Ca]3.1 mRNA levels [aproximate sign]2.5 fold in both right coronary artery (RCA) sections and CSMCs, while addition of Apo prevented the increase. Furthermore, inhibition of NADPH oxidase abolished the bFGF-induced increase in coronary smooth muscle K[subscript Ca]3.1 protein expression and CSMC K[subscript Ca]3.1 channel activity. Treatment with bFGF significantly increased activator protein-1 (AP-1) promoter activity which was inhibited by addition of Apo. RCA and CSMC express all four cardiovascular Nox isoforms (Nox1, Nox2, Nox4, Nox5) with Nox4 being the predominant isoform. Treatment with bFGF decreased Nox1, Nox2, and Nox4 CSMC message, while treatment with Apo increased the mRNA expression of all four isoforms. Knock down of Nox2 and Nox4 did not affect the K[subscript Ca]3.1 message response to bFGF or Apo. Consistent with our earlier findings of increased medial K[subscript Ca]3.1 expression in FH coronaries; whole vessel K[subscript Ca]3.1 mRNA expression was increased in FH coronary smooth muscle and Nox2 rather than Nox4 was the predominant Nox isoform. Our findings demonstrate that K[subscript Ca]3.1 is upregulated in coronary smooth muscle of FH swine and support previous research indicating K[subscript Ca]3.1 plays a key role in the development and progression of atherosclerosis. Our findings also provide novel evidence that NADPH oxidase contributes to VSMC phenotypic modulation associated with atherosclerosis through AP-1 transcriptional upregulation of K[subscript Ca]3.1.

Reactive oxygen species are classically described as occurring as an accidental byproduct of respiration, and are generally thought to be deleterious to biologic systems. The phagocyte nicotinamide adenine dinucleotide phosphate oxidase provides an example of deliberate reactive oxygen species generation, but the function of this enzyme is to oxidatively modify bacteria as part of bactericidal mechanisms. The discovery of a family of nicotinamide adenine dinucleotide (phosphate) oxidases related to the phagocyte oxidase, the Nox/Duox family, provides additional examples of deliberate generation of reactive oxygen species. This article describes this new family of enzymes and considers hypotheses for their function. Potential roles of Nox/Duox in generation of reactive oxygen species that function in cell signaling (related to growth and angiogenesis), immune function, hypoxic response, and oxidative modification of extracellular matrix proteins are discussed.

Hyperhydricity is a physiological disorder associated with oxidative stress. Reactive oxygen species (ROS) generation in plants is initiated by various enzymatic sources, including plasma membrane-localized nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, cell wall-bound peroxidase (POD), and apoplastic polyamine oxidase (PAO). The origin of the oxidative burst associated with hyperhydricity remains unknown. To investigate the role of NADPH oxidases, POD, and PAO in ROS production and hyperhydricity, exogenous hydrogen peroxide (H2O2) and inhibitors of each ROS-producing enzyme were applied to explore the mechanism of oxidative stress induction in garlic plantlets in vitro. A concentration of 1.5mM H2O2 increased endogenous ROS production and hyperhydricity occurrence and enhanced the activities of NADPH oxidases, POD, and PAO. During the entire treatment period, NADPH oxidase activity increased continuously, whereas POD and PAO activities exhibited a transient increase and subsequently declined. Histochemical and cytochemical visualization demonstrated that specific inhibitors of each enzyme effectively suppressed ROS accumulation. Moreover, superoxide anion generation, H2O2 content, and hyperhydric shoot frequency in H2O2-stressed plantlets decreased significantly. The NADPH oxidase inhibitor was the most effective at suppressing superoxide anion production. The results suggested that NADPH oxidases, POD, and PAO were responsible for endogenous ROS induction. NADPH oxidase activation might play a pivotal role in the oxidative burst in garlic plantlets in vitro during hyperhydricity.