Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.3.1 (NADPH oxidase)
11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Nef protein of the human immunodeficiency virus type 1 (HIV-1) plays a crucial role in AIDS pathogenesis by modifying host cell signaling pathways. We investigated the effects of Nef on the NADPH oxidase complex, a key enzyme involved in the generation of reactive oxygen species during the respiratory burst in human monocyte/macrophages. We have recently shown that the inducible expression of HIV-1 Nef in human macrophages cell line modulates in bi-phasic mode the superoxide anion release by NADPH oxidase, inducing a fast increase of the superoxide production, followed by a delayed strong inhibition mediated by Nef-induced soluble factor(s). Our study is focused on the molecular mechanisms involved in Nef-mediated activation of NADPH oxidase and superoxide anion release. Using U937 cells stably transfected with different Nef alleles, we found that both Nef membrane localization and intact SH3-binding domain are needed to induce superoxide release. The lack of effect during treatment with a specific MAPK pathway inhibitor, PD98059, demonstrated that Nef-induced superoxide release is independent of Erk1/2 phosphorylation. Furthermore, Nef induced the phosphorylation and then the translocation of the cytosolic subunit of NADPH oxidase complex p47(phox) to the plasma membrane. Adding the inhibitor PP2 prevented this process, evidencing the involvement of the Src family kinases on Nef-mediated NADPH oxidase activation. In addition, LY294002, a specific inhibitor of phosphoinositide 3-kinase (PI3K) inhibited both the Nef-induced p47(phox) phosphorylation and the superoxide anion release. These data indicate that Nef regulates the NADPH oxidase activity through the activation of the Src kinases and PI3K.
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PMID:HIV-1 Nef induces p47(phox) phosphorylation leading to a rapid superoxide anion release from the U937 human monoblastic cell line. 1913 May 4

Neutrophils are highly specialized innate effector cells that have evolved for killing of pathogens. Human neonates have a common multifactorial syndrome of neutrophil dysfunction that is incompletely characterized and contributes to sepsis and other severe infectious complications. We identified a novel defect in the antibacterial defenses of neonates: inability to form neutrophil extracellular traps (NETs). NETs are lattices of extracellular DNA, chromatin, and antibacterial proteins that mediate extracellular killing of microorganisms and are thought to form via a unique death pathway signaled by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-generated reactive oxygen species (ROS). We found that neutrophils from term and preterm infants fail to form NETs when activated by inflammatory agonists-in contrast to leukocytes from healthy adults. The deficiency in NET formation is paralleled by a previously unrecognized deficit in extracellular bacterial killing. Generation of ROSs did not complement the defect in NET formation by neonatal neutrophils, as it did in adult cells with inactivated NADPH oxidase, demonstrating that ROSs are necessary but not sufficient signaling intermediaries and identifying a deficiency in linked or downstream pathways in neonatal leukocytes. Impaired NET formation may be a critical facet of a common developmental immunodeficiency that predisposes newborn infants to infection.
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PMID:Impaired neutrophil extracellular trap (NET) formation: a novel innate immune deficiency of human neonates. 1996 99

Although it has been well documented that drugs of abuse such as cocaine cause enhanced progression of human immunodeficiency virus (HIV)-associated neuropathological disorders, the underlying mechanisms mediating these effects remain poorly understood. The present study demonstrated that exposure of rat primary neurons to both cocaine and gp120 resulted in increased cell toxicity compared to cells treated with either factor alone. The combinatorial toxicity of cocaine and gp120 was accompanied by an increase in both caspase-3 activity and expression of the proapoptotic protein Bax. Furthermore, increased neurotoxicity in the presence of both the agents was associated with a concomitant increase in the production of intracellular reactive oxygen species and loss of mitochondrial membrane potential. Increased neurotoxicity mediated by cocaine and gp120 was ameliorated by NADPH oxidase inhibitor apocynin, thus underscoring the role of oxidative stress in this cooperation. Signaling pathways including c-jun N-teminal kinase (JNK), p38, extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinases (MAPK), and nuclear factor (NF)-kappaB were also identified to be critical in the neurotoxicity induced by cocaine and gp120. These findings thus underscore the role of oxidative stress, mitochondrial and MAPK signal pathways in cocaine and HIV gp120-mediated neurotoxicity.
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PMID:Cocaine and human immunodeficiency virus type 1 gp120 mediate neurotoxicity through overlapping signaling pathways. 1931 45

Chronic granulomatous disease (CGD) is an inherited immunodeficiency disorder caused by defects in NADPH oxidase and characterized by recurrent life-threatening bacterial and fungal infections. Although CGD has been considered to be a target for gene therapy, bone marrow transplantation (BMT) is now selected as the radical treatment in most cases. We performed BMT in a patient with CGD with severe infections and experienced respiratory complications of diffuse alveolar haemorrhage and/or infection-associated alveolar haemorrhage. We suggest that attention be paid to signs of onset of alveolar haemorrhage during BMT in CGD patients.
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PMID:Respiratory complications after haematopoietic stem cell transplantation in a patient with chronic granulomatous disease. 1932 Aug 54

CGD is an immunodeficiency caused by deletions or mutations in genes that encode subunits of the leukocyte NADPH oxidase complex. Normally, assembly of the NADPH oxidase complex in phagosomes of certain phagocytic cells leads to a "respiratory burst", essential for the clearance of phagocytosed micro-organisms. CGD patients lack this mechanism, which leads to life-threatening infections and granuloma formation. However, a clear picture of the clinical course of CGD is hampered by its low prevalence (approximately 1:250,000). Therefore, extensive clinical data from 429 European patients were collected and analyzed. Of these patients 351 were males and 78 were females. X-linked (XL) CGD (gp91(phox) deficient) accounted for 67% of the cases, autosomal recessive (AR) inheritance for 33%. AR-CGD was diagnosed later in life, and the mean survival time was significantly better in AR patients (49.6 years) than in XL CGD (37.8 years), suggesting a milder disease course in AR patients. The disease manifested itself most frequently in the lungs (66% of patients), skin (53%), lymph nodes (50%), gastrointestinal tract (48%) and liver (32%). The most frequently cultured micro-organisms per episode were Staphylococcus aureus (30%), Aspergillus spp. (26%), and Salmonella spp. (16%). Surprisingly, Pseudomonas spp. (2%) and Burkholderia cepacia (<1%) were found only sporadically. Lesions induced by inoculation with BCG occurred in 8% of the patients. Only 71% of the patients received antibiotic maintenance therapy, and 53% antifungal prophylaxis. 33% were treated with gamma-interferon. 24 patients (6%) had received a stem cell transplantation. The most prominent reason of death was pneumonia and pulmonary abscess (18/84 cases), septicemia (16/84) and brain abscess (4/84). These data provide further insight in the clinical course of CGD in Europe and hopefully can help to increase awareness and optimize the treatment of these patients.
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PMID:Chronic granulomatous disease: the European experience. 1938 1

The NADPH oxidase (NOX), an oligomeric enzyme, plays a key role in polymorphonuclear neutrophil (PMN)-mediated host defense by producing cytotoxic superoxide anion (O(2)( )). Whereas in vitro and biochemical studies have examined the assembly and activation of this important host immune defense system, few studies have examined the function of NOX in human patients with primary immunodeficiency other than chronic granulomatous disease. We studied the activation of NOX in PMN from patients with two distinct immunodeficiencies, IL-1R-associated kinase (IRAK)4 deficiency and NF-kappaB essential modulator (NEMO or IkappaB kinase gamma) deficiency. We observed impaired O(2)( ) generation by LPS-treated and fMLP-activated IRAK4-deficient PMN that correlated with decreased phosphorylation of p47(phox) and subnormal translocation of p47(phox), p67(phox), Rac2, and gp91(phox)/Nox2 to the membranes indicating that TLR4 signaling to the NOX activation pathway requires IRAK4. NEMO-deficient PMN generated significantly less O(2)( ) in response to LPS-primed fMLP and translocated less p67(phox) than normal PMN, although p47(phox) and Rac2 translocation were normal. Generally, responses of NEMO-deficient cells were intermediate between IRAK4-deficient cells and normal cells. Decreased LPS- and fMLP-induced phosphorylation of p38 MAPK in both IRAK4- and NEMO-deficient PMN implicates additional signal transduction pathways in regulating PMN activation by LPS and fMLP. Decreased activation of NOX may contribute to the increased risk of infection seen in patients with IRAK4 and NEMO deficiency.
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PMID:Impaired priming and activation of the neutrophil NADPH oxidase in patients with IRAK4 or NEMO deficiency. 1972 66

Chronic granulomatous disease (CGD) is a rare inherited immunodeficiency disorder. The clinical presentation is varied depending on the degree of involvement of the NADPH oxidase system responsible for the oxidative burst of neutrophils. We present 3 cases of variant X-linked CGD in an effort to introduce the disease and highlight the importance and limitations of CGD screening. The variant X-linked form of CGD results in a less severe phenotype and frequently presents later in life. Variant X-linked CGD is difficult to diagnose, but is becoming more readily recognized based on improved testing methods. A high index of suspicion in the setting of unusual infections such as Burkholderia cepacia pneumonia is essential to make the diagnosis. Family screening can lead to early intervention, prophylaxis, and appropriate genetic counseling.
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PMID:Family clusters of variant X-linked chronic granulomatous disease. 2011 50

Chronic granulomatous disease (CGD), an immunodeficiency with recurrent pyogenic infections and granulomatous inflammation, results from loss of phagocyte superoxide production by recessive mutations in any 1 of 4 genes encoding subunits of the phagocyte NADPH oxidase. These include gp91(phox) and p22(phox), which form the membrane-integrated flavocytochrome b, and cytosolic subunits p47(phox) and p67(phox). A fifth subunit, p40(phox), plays an important role in phagocytosis-induced superoxide production via a phox homology (PX) domain that binds to phosphatidylinositol 3-phosphate (PtdIns(3)P). We report the first case of autosomal recessive mutations in NCF4, the gene encoding p40(phox), in a boy who presented with granulomatous colitis. His neutrophils showed a substantial defect in intracellular superoxide production during phagocytosis, whereas extracellular release of superoxide elicited by phorbol ester or formyl-methionyl-leucyl-phenylalanine (fMLF) was unaffected. Genetic analysis of NCF4 showed compound heterozygosity for a frameshift mutation with premature stop codon and a missense mutation predicting a R105Q substitution in the PX domain. Parents and a sibling were healthy heterozygous carriers. p40(phox)R105Q lacked binding to PtdIns(3)P and failed to reconstitute phagocytosis-induced oxidase activity in p40(phox)-deficient granulocytes, with premature loss of p40(phox)R105Q from phagosomes. Thus, p40(phox) binding to PtdIns(3)P is essential for phagocytosis-induced oxidant production in human neutrophils and its absence can be associated with disease.
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PMID:A new genetic subgroup of chronic granulomatous disease with autosomal recessive mutations in p40 phox and selective defects in neutrophil NADPH oxidase activity. 1969 3

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is critical for phagocyte anti-microbial activity and plays a major role in innate immunity. Defects in genes coding for components of the NADPH oxidase enzyme system are responsible for chronic granulomatous disease (CGD), a rare primary neutrophil immunodeficiency associated with recurrent, life-threatening bacterial and fungal infections. Microbial killing and digestion within the neutrophil phagosomal compartment are defective in these patients. NADPH oxidase activity is also crucial for optimal macrophage and dendritic cell function and has recently been implicated in both cross-presentation and T-cell priming. We present evidence of impaired macrophage function in CGD, with attenuated pro-inflammatory cytokine and increased interleukin-10 secretion following bacterial stimulation. These results highlight additional abnormalities in macrophage function associated with CGD and the importance of NADPH oxidase activity in immunity.
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PMID:Impaired macrophage function following bacterial stimulation in chronic granulomatous disease. 1974 Mar 82

Chronic granulomatous disease (CGD) is a primary immunodeficiency, a phagocyte defect that appears in 1:200,000 live births and is produced by mutations in the genes that codify for the enzyme nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). The inheritance form is X linked (> 60%) or autosomic recesive (30-40%). The NADPH oxidase is responsible for the production of reactive oxygen species (ROS) in the activated phagocyte ("respiratory burst"). When present, mutations on the NAPDH oxidase genes do not allow the ROS production, making the neutrophils of these patients incapable to destroy pathogens. These patients are especially susceptible to infections by staphylococcus, fungi and some gram-negative bacteria. The main clinical manifestations include recurrent life-threatening episodes of lymphadenitis, abscess, pneumonias, osteomyelitis, granuloma formation and sepsis. The diagnosis is suggested by a history of recurrent infections, familiar cases, fail to grow and confirmed with an altered test of ROS production and the specific mutation. Allogenic stem cells transplant is the curative treatment. The early diagnosis and the treatment with prophylactic antibiotics and interferon-gamma have modified favorably the morbidity and mortality of these patients.
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PMID:[Chronic granulomatous disease]. 1999 20


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