Effect Of NADPH Oxidase Inhibitor Research Articles

Effects of NADPH oxidase inhibitor of the Etlingera elatior (E. elatior) fruits extracts in animal sepsis models

Effects of NADPH oxidase inhibitor of the Etlingera elatior (E. elatior) fruits extracts in animal sepsis models

Peripheral and central effects of NADPH oxidase inhibitor, mitoapocynin, in a rat model of diisopropylfluorophosphate (DFP) toxicity.

Organophosphates (OP) are highly toxic chemical nerve agents that have been used in chemical warfare. Currently, there are no effective medical countermeasures (MCMs) that mitigate the chronic effects of OP exposure. Oxidative stress is a key mechanism underlying OP-induced cell death and inflammation in the peripheral and central nervous systems and is not mitigated by the available MCMs. NADPH oxidase (NOX) is one of the leading producers of reactive oxygen species (ROS) following status epilepticus (SE). In this study, we tested the efficacy of the mitochondrial-targeted NOX inhibitor, mitoapocynin (MPO) (10 mg/kg, oral), in a rat diisopropylfluorophosphate (DFP) model of OP toxicity. In DFP-exposed animals, MPO decreased oxidative stress markers nitrite, ROS, and GSSG in the serum. Additionally, MPO significantly reduced proinflammatory cytokines IL-1β, IL-6, and TNF-α post-DFP exposure. There was a significant increase in GP91phox, a NOX2 subunit, in the brains of DFP-exposed animals 1-week post-challenge. However, MPO treatment did not affect NOX2 expression in the brain. Neurodegeneration (NeuN and FJB) and gliosis [microglia (IBA1 and CD68), and astroglia (GFAP and C3)] quantification revealed a significant increase in neurodegeneration and gliosis after DFP-exposure. A marginal reduction in microglial cells and C3 colocalization with GFAP in DFP + MPO was observed. The MPO dosing regimen used in this study at 10 mg/kg did not affect microglial CD68 expression, astroglial count, or neurodegeneration. MPO reduced DFP-induced oxidative stress and inflammation markers in the serum but only marginally mitigated the effects in the brain. Dose optimization studies are required to determine the effective dose of MPO to mitigate DFP-induced changes in the brain.

Effect of NADPH oxidase inhibitors in an experimental retinal model of excitotoxicity

NADPH oxidases (NOX) are activated in ischemic conditions leading to increases in reactive oxygen species (ROS) and neurotoxicity. The aim of the present study was to investigate the role of NOX in the development of retinal pathologies, associated with excitotoxicity and the evaluation of NOX inhibitors as putative therapeutic agents. Sprague-Dawley rats were used for the induction of the in vivo retinal model of (RS)-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid hydrobromide (AMPA) excitotoxicity. Rats were intravitreally administered with PBS, AMPA (42 nmoles) or AMPA + NOX inhibitors, VAS2870 (pan-NOX inhibitor, 10−6-10−4 M), ML171 (NOX1 inhibitor, 10−5, 10−4 M), and GLX7013114 (NOX4 inhibitor, 10−4 M). Immunohistochemical studies were performed using antibodies raised against nitrotyrosine, a ROS/oxidative stress marker, bNOS, a neuronal marker for nitric oxide synthase and the macro and microglia markers, glial fibrillary acidic protein and ionized calcium-binding adaptor molecule-1, respectively. VAS2870 and ML171 showed neuroprotective and anti-inflammatory actions reversing the AMPA induced reduction of bNOS expressing amacrine cells and attenuating macro/microglial activation. GLX7013114 (10−4 M) did not protect bNOS expressing amacrine cells, but it did attenuate the AMPA induced increase in nitrotyrosine positive cells and activation of glial cells. These results suggest that NOX1, NOX4 and possibly NOX2 (due to the actions of VAS2870) play an important role in the pathophysiology of the retina and that NOX inhibitors are putative neuroprotective and anti-inflammatory agents against retinal abnormalities caused by excitotoxicity.

Nitric oxide protected against NADPH oxidase-derived superoxide generation in vascular endothelium: Critical role for heme oxygenase-1

NADPH oxidase-derived superoxide (O2−) generation is usually considered as an important factor to the pathogenesis of cardiovascular diseases. Nitric oxide (NO), previously viewed as a key regulator of cardiovascular function, is identified to induce expression of heme oxygenase-1 (HO-1), an antioxidant enzyme in blood vessels. In this study, we tested whether NO might modulate NADPH oxidase activity in vascular endothelium via HO-1. In vascular endothelial cells, NO donor (diethylenetriamine/nitric oxide adduct) significantly attenuated NADPH oxidase-derived O2− generation via a HO-1-dependent mechanism. Mechanistically, the protective effects of NO were (1) linked to increased expression of HO-1, (2) similar to the effects of NADPH oxidase inhibitor, (3) could be abolished by the specific siRNA against HO-1 expression or HO-1 activity inhibitor and (4) similar to the effects of HO-1 end product bilirubin. Moreover, bilirubin seemed to interrupt the assembly and activation of NADPH oxidase. In addition, NO inhibited H2O2-induced endothelial dysfunction through activation of HO-1. In agreement with these in vitro data, aortic NADPH oxidase activity was increased in NO-deficient mice while the endothelial function was simultaneously impaired. Our results suggested that suppression of NADPH oxidase-dependent oxidative stress may represent a novel mechanism underlying the cardiovascular protection of NO/HO-1 pathway.

Effects of NADPH Oxidase Inhibitors and Mitochondria-Targeted Antioxidants on Amyloid β1-42-Induced Neuronal Deaths in Mouse Mixed Cortical Cultures.

The Amyloid β peptide (Aβ) is a main component of senile plaques in Alzheimer's disease. Currently, NADPH oxidase (NOX) and mitochondria are considered as primary sources of ROS induced by Aβ. However, the contribution of NOX and mitochondria to Aβ-induced ROS generation has not been well defined. To delineate the relative involvement of NOX and mitochondria in Aβ-induced ROS generation and neuronal death in mouse cortical cultures, we examined the effect of NOX inhibitors, apocynin and AEBSF, and the mitochondria-targeted antioxidants (MTAs), mitotempol and mitoquinone, on Aβ-induced ROS generation and neuronal deaths. Cell death was assessed by measuring lactate dehydrogenase efflux in bathing media at 24 and 48 hrs after exposure to Aβ1-42. Aβ1-42 induced dose- and time-dependent neuronal deaths in cortical cultures. Treatment with 20 µM Aβ1-42 markedly and continuously increased not only the DHE fluorescence (intracellular ROS signal), but also the DHR123 fluorescence (mitochondrial ROS signal) up to 8 hrs. Treatment with apocynin or AEBSF selectively suppressed the increase in DHE fluorescence, while treatment with mitotempol selectively suppressed the increase in DHR123 fluorescence. Each treatment with apocynin, AEBSF, mitotempol or mitoquinone significantly attenuated the Aβ1-42-induced neuronal deaths. However, any combined treatment with apocynin/AEBSF and mitotempol/mitoquinone failed to show additive effects. These findings indicate that 20 µM Aβ1-42 induces oxidative neuronal death via inducing mitochondrial ROS as well as NOX activation in mixed cortical cultures, but combined suppression of intracellular and mitochondrial ROS generation fail to show any additive neuroprotective effects against Aβ neurotoxicity.

GW24-e2914 Involvement of vascular peroxidase 1 in the endothelial dysfunction in hypertension

ObjectivesVascular peroxidase 1 (VPO1) is a new heme-containing peroxidase, which can utilise hydrogen peroxide (H2O2) generated from co-expressed NADPH oxidase (NOX) to produce hypochlorous acid (HOCl) and catalyse peroxidative reactions....

GW24-e3078 Vascular peroxidase 1 is involved in pulmonary arterial hypertension via mediate pulmonary arterial smooth cells proliferation

ObjectivesHypoxia could induce pulmonary arterial smooth muscle cells (PASMCs) proliferation via hydrogen peroxide (H2O2)-induced oxidative stress. Our previous research had demonstrated that vascular peroxidase 1 (VPO1) could utilise hydrogen peroxide...

GW24-e3020 Involvement of vascular peroxidase 1 in angiotensin II-induced H9c2 cells hypertrophy

ObjectivesOxidative stress induces hypertrophic gene expression and collagen deposition that mediates cardiac hypertrophy and myocardial fibrosis. Vascular peroxidase 1 (VPO1) is a new heme-containing peroxidase, which can utilise hydrogen peroxide...

Effect of NADPH-oxidase inhibitors in the experimental model of zymosan-induced shock in mice

The aim of this study was to investigate the effects of NADPH-oxidase inhibitors, in a mouse model of zymosan. Zymosan-induced shock was induced in mice by administration of zymosan (500 mg/kg, i.p.). The pharmacological treatment was the administration of apocynin (5 mg/kg 10% DMSO i.p.) and diphenylene iodonium chloride (DPI) (1 mg/kg i.v.) 1 h and 6 h after zymosan administration. MOF and systemic inflammation in mice was assessed 18 h after administration of zymosan. NADPH-oxidase inhibitors caused a significant reduction of the (1) peritoneal exudate formation, (2) neutrophil infiltration, (3) multiple organ dysfunction syndrome, (4) nitrotyrosine, (5) poly (ADP-ribose) (PAR), (6) cytokine formation, (7) adhesion molecule expression, (8) nuclear factor (NF-κB) expression and (9) apoptosis induced by zymosan. Moreover, NADPH-oxidase inhibitors treatment significantly reduced the systemic toxicity, the loss in body weight and the mortality caused by zymosan. This study has shown that NADPH-oxidase inhibitors attenuate the degree of zymosan-induced non-septic shock in mice.

Effect of nadph oxidase inhibitor and superoxide dismutase mimetic on the expression of nitric oxide synthase in spontaneously hypertensive rats

Effect of nadph oxidase inhibitor and superoxide dismutase mimetic on the expression of nitric oxide synthase in spontaneously hypertensive rats

Antiinflammatory effects of NADPH oxidase inhibitors.

Proinflammatory cytokines prime the membrane-bound NADPH oxidase of neutrophils and monocytes of mice suffering from experimental arthritis so as to attain an activated state, which, upon a second stimulus, releases 6-fold increased levels of reactive oxygen species (ROS) than do unprimed phagocytes. Enhanced NADPH oxidase activity deregulates ROS-dependent signal transduction pathways of inflammation, which play a crucial role in the pathogenesis of arthritis. The antiarthritic reactivity of two inhibitors of NADPH oxidase, diphenylene iodoniumchloride (DPI) and staurosporine, was tested in male DBA/1 x B10A(4R) hybrid mice suffering from potassium peroxochromate arthritis. Daily doses of 2.8 mumol/kg of DPI or 30 nmol/kg of staurosporine sufficed to inhibit the arthritis by 50%. A complete inhibition was obtained with 10 mumol/kg of DPI, and 100 nmol/kg of staurosporine suppressed the arthritis by 85%. The onset, progression, and remission of arthritis correlated to both the activity of phagocytic NADPH oxidase (r = 0.750) and to overt disease symptoms as judged by the arthritis index. Our data support the hypothesis that oxidative stress plays a pivotal role in the pathology of arthritis, which can be therapeutically targeted by NADPH oxidase inhibitors.

Effects of NADPH oxidase inhibitors on hypoxic vasoconstriction in buffer-perfused rabbit lungs.

The involvement of NADPH oxidase in hypoxic pulmonary vasoconstriction (HPV) was investigated in buffer-perfused rabbit lungs, employing the inhibitors diphenyleneiodonium (DPI) and apocynin. Responses to the vasoconstrictors U-46619 and angiotensin II (ANG II) were used to test specificity. Lung nitric oxide (NO) generation was assessed by on-line monitoring of NO exhalation (chemiluminescence), and the efficacy of DPI and apocynin on the NADPH oxidase-dependent O2- generation was quantified in alveolar macrophages by fluorescent-activated cell sorter technique. In a concentration range between 1 and 5 mM, apocynin inhibited macrophage respiratory burst and HPV but similarly suppressed U-46619-induced vasoconstrictor responses. DPI inhibited macrophage O2- generation in concentrations > or = 0.5 microM. At doses between 0.5 and 1.5 microM, DPI blocked lung NO generation, thereby increasing HPV. At higher doses (4 microM), in contrast, DPI fully blocked the hypoxia-induced pressor responses, whereas the vasoconstrictor responses to U-46619 and [Asn1, Val5] ANG II were not diminished. In the presence of NG-monomethyl-L-arginine, used to block lung NO generation throughout, DPI exhibited only the monophasic selective inhibition of HPV. We conclude that apocynin lacks specificity for HPV, but DPI, in addition to inhibiting lung NO generation, causes selective blockade of the hypoxia-induced vasoconstriction. This finding supports the hypothesis that an NADPH oxidase is involved in hypoxia sensing or specific signal transduction events underlying HPV.