NADPH oxidase 2 plays a protective role in experimental Aspergillus fumigatus keratitis in mice through killing fungi and limiting the degree of inflammation.

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

Mucormycosis in chronic granulomatous disease: Association with iatrogenic immunosuppression

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.

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.

Reactive oxygen species (ROS) and nitrogen-derived oxidants, such as nitric oxide (NO), are produced by immune cells through the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) and nitric oxide synthases (NOS), respectively. These pro-oxidants disrupt physiological homeostasis, contributing to hyperalgesia, the excessive release of inflammatory markers and oxidative stress during ulcerative colitis (UC). Consequently, diphenyleneiodonium chloride (DPI), an inhibitor of NOXs and NOS, could be effective in alleviating visceral pain and UC. This study examines the antioxidant and analgesic properties of DPI, as well as its ability to modulate oxidative stress and pro-inflammatory responses in UC. The antioxidant properties of DPI and its ability to bind free iron were determined using ABTS and DPPH tests, as well as a ferrous iron chelating capacity assay. DPI's analgesic activity was investigated using a 0.6% acetic acid (AA) mouse model of hyperalgesia, and its preventive effects against UC were determined using a 3% AA rat model of UC. Our results demonstrate that DPI limits free radicals, chelates ferrous iron and reduces writhing number (Wn) by p < 0.001, confirming its analgesic activity. Furthermore, intraperitoneal administration of DPI (100ng/kg) protected rats from UC by repairing large-scale colonic damage, lowering oxidative stress by decreasing NO levels and restoring antioxidant enzymatic activities in colonic tissue. DPI also lowers plasmatic C-reactive protein (C-RP), NO content, lactate dehydrogenase (LDH) and γ-glutamyl transferase (γ-GT) activity during colitis. Therefore, targeting NOXs and NOS with DPI could be a promising strategy for treating inflammatory diseases such as colitis.

To understand the role of reactive oxygen species (ROS) in regulation of the plasma membrane (PM) H+-ATPase in acid-stressed Masson pine roots, different acidity (pH6.6 as the control, pH5.6 and pH4.6) of simulated acid rain (SAR) added with and without external chemicals (H2O2, enzyme inhibitors and ROS scavenger) was prepared. After 30days of SAR exposure, the plant morphological phenotype attributes, levels of cellular ROS and lipid peroxidation, enzymatic activities of antioxidants, PM nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and PM H+-ATPase activity in pine seedlings were measured. Compared with the control, the growth of pine seedlings exposed to SAR in the presence or absence of H2O2 was well-maintained, but the application of Na3VO4, 1,3-dimethyl-2-thiourea, N, N-dimethylthiourea (DMTU) and diphenyleneiodonium chloride (DPI) caused a substantial growth inhibition. In addition, SAR exposure, SAR with H2O2 treatment, and SAR with Na3VO4 treatment increased the cellular H2O2 content, O2- content and malondialdehyde (MDA) content, while the use of DMTU and DPI lead to relatively low levels. Similarly, the enzymatic activities of antioxidants, PM NADPH oxidase and PM H+-ATPase in acid stressed pine seedlings elevated with the increasing acidity. A significant stimulation of these enzymatic activities obtained from SAR with H2O2 treatment was observed, whereas which decreased obviously with the addition of Na3VO4, DMTU and DPI (P<0.05). Moreover, a positive correlation was found between plant morphological attributes and the PM H+-ATPase activity (P<0.05). Besides, the PM H+-ATPase activity positively correlated with the cellular ROS contents and the enzymatic activities of antioxidants and PM NADPH oxidase (P<0.05). Therefore, the PM H+-ATPase is instrumental in the growth of pine seedlings resisting to acid stress by enhancing its activity. The process involves the signaling transduction of cellular ROS and coordination with PM NADPH oxidase.

Uraemia and cardiovascular disease appear to be associated with an increased oxidative burden. One of the key players in the genesis of reactive oxygen species (ROS) is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Based on initial experiments demonstrating a decreased inhibitory effect on NADPH oxidase activity in the presence of plasma from patients with CKD-5D after dialysis compared with before dialysis, we investigated the effect of 48 known and commercially available uraemic retention solutes on the enzymatic activity of NADPH oxidase. Mononuclear leucocytes isolated from buffy coats of healthy volunteers were isolated, lysed and incubated with NADH in the presence of plasma from healthy controls and patients with CKD-5D. Furthermore, the leucocytes were lysed and incubated in the presence of uraemic retention solute of interest and diphenyleneiodonium chloride (DPI), an inhibitor of NADPH oxidase. The effect on enzymatic activity of NADPH oxidase was quantified within an incubation time of 120min. Thirty-nine of the 48 uraemic retention solutes tested had a significant decreasing effect on NADPH oxidase activity. Oxalate has been characterized as the strongest inhibitor of NADPH oxidase (90% of DPI inhibition). Surprisingly, none of the uraemic retention solutes we investigated was found to increase NADPH oxidase activity. Furthermore, plasma from patients with CKD-5D before dialysis caused significantly higher inhibitory effect on NADPH oxidase activity compared with plasma from healthy subjects. However, this effect was significantly decreased in plasma from patients with CKD-5D after dialysis. The results of this study show that uraemic retention solutes modulated the activity of the NADPH oxidase. The results of this study might be the basis for the development of inhibitors applicable as drug in the situation of increased oxidative stress.

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

Induction of hepatoma carcinoma cell apoptosis through activation of the JNK–nicotinamide adenine dinucleotide phosphate (NADPH) oxidase–ROS self-driven death signal circuit

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

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) was originally identified in immune cells as playing an important microbicidal role. In stroke and cerebrovascular disease, inflammation is increasingly being recognized as contributing negatively to neurological outcome, with NOX as an important source of superoxide. Several labs have now shown that blocking or deleting NOX in the experimental stroke models protects from brain ischemia. Recent work has implicated glucose as an important NOX substrate leading to reperfusion injury, and that NOX inhibition can improve the detrimental effects of hyperglycemia on stroke. NOX inhibition also appears to ameliorate complications of thrombolytic therapy by reducing blood–brain barrier disruption, edema formation, and hemorrhage. Further, NOX from circulating inflammatory cells seems to contribute more to ischemic injury more than NOX generated from endogenous brain residential cells. Several pharmacological inhibitors of NOX are now available. Thus, blocking NOX activation may prove to be a promising treatment for stroke as well as an adjunctive agent to prevent its secondary complications.

T cell receptor (TCR) stimulation induces rapid generation of reactive oxygen species, although the mechanisms for this are unclear. Here we found that T cells expressed a functional phagocyte-type nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. TCR crosslinking induced oxidase activation through the recruitment of preformed Fas ligand and Fas. TCR stimulation induced three separable events generating reactive oxygen species: rapid hydrogen peroxide production independent of Fas or NADPH oxidase; sustained hydrogen peroxide production dependent on both Fas and NADPH oxidase; and delayed superoxide production that was dependent on Fas ligand and Fas yet independent of NADPH oxidase. NADPH oxidase-deficient T cells showed enhanced activation of the kinase Erk and a relative increase in T helper type 1 cytokine secretion. Thus, mature T cells express a phagocyte-type NADPH oxidase that regulates elements of TCR signaling.

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.