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:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neutrophil elastase (NE) is thought to be the most important protease which damages the cystic fibrosis (CF) lung. Attempts have been made to suppress this activity using the plasma-derived inhibitor, alpha(1)-antitrypsin (AAT). In this pilot study, the safety and efficacy of inhaled recombinant human AAT (rAAT) as a treatment for CF were investigated. Thirty-nine patients participated in a prospective, double-blinded, randomized, placebo-controlled phase II trial to examine the effect of rAAT (500, 250, and 125 mg) on sputum NE activity. Sputum myeloperoxidase (MPO), interleukin-8, tumor necrosis factor receptors, sputum and plasma NE/AAT complexes, and safety parameters were also measured. Subjects were randomized to receive nebulized treatment once a day for 4 weeks, followed by 2-4 weeks with no study treatment, and then a 2-week rechallenge phase. Trends toward a reduction in NE activity were observed in patients treated with 500 mg and 250 mg of rAAT compared to placebo. Sputum NE/AAT complex and MPO levels were lower on rAAT compared to placebo. No major adverse events and, in particular, no allergic reactions to rAAT were observed. Although significant differences between rAAT and placebo for sputum NE activity were not observed, some improvements were found for secondary efficacy variables. This study demonstrated that nebulized rAAT is safe and well-tolerated, but has a limited effect on NE activity and other markers of inflammation.
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PMID:Safety and efficacy of recombinant alpha(1)-antitrypsin therapy in cystic fibrosis. 1637 52

The engineered protein inhibitor of human neutrophil elastase, Epi-hNE4, is being developed for the treatment of cystic fibrosis. Like many recombinant proteins, Epi-hNE4 may induce antibodies in pre-clinical species and in humans. The aim of this report was to validate an ELISA to assess its immunogenicity in monkeys. We have designed and optimized a classical ELISA in which Epi-hNE4 was coated directly on microtitre plates and the antibodies were detected using a secondary antibody labelled with peroxidase. We report implementation of the recent recommendations proposed for the validation of immunogenicity assessment. The cut-off point was determined by means of statistical analysis of negative samples. Linearity, reproducibility, stability and specificity were estimated using quality control samples obtained from a pool of positive samples. The method was applied to monkeys given Epi-hNE4 by inhalation. A confirmation test and a neutralization assay were developed in order to further assess positive samples. In conclusion, we present here one of the first examples of validation in application of recent recommendations [A.R. Mire-Sluis, Y.C. Barrett, V. Devanarayan, E. Koren, H. Liu, M. Maia, T. Parish, G. Scott, G. Shankar, E. Shores, S.J. Swanson, G. Taniguchi, D. Wierda, L.A. Zuckerman, J. Immunol. Methods 289 (2004) 1-16].
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PMID:Validation of an ELISA for determination of antibodies induced in monkeys against Epi-hNE4, a recombinant protein inhibitor of human neutrophil elastase. 1711 11

Chronic respiratory infections in cystic fibrosis result from CFTR channel mutations but how these impair antibacterial defense is less clear. Airway host defense depends on lactoperoxidase (LPO) that requires thiocyanate (SCN-) to function and epithelia use CFTR to concentrate SCN- at the apical surface. To test whether CFTR mutations result in impaired LPO-mediated host defense, CF epithelial SCN- transport was measured. CF epithelia had significantly lower transport rates and did not accumulate SCN- in the apical compartment. The lower CF [SCN-] did not support LPO antibacterial activity. Modeling of airway LPO activity suggested that reduced transport impairs LPO-mediated defense and cannot be compensated by LPO or H2O2 upregulation.
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PMID:The lactoperoxidase system links anion transport to host defense in cystic fibrosis. 1720 67

Decreased survival in patients with cystic fibrosis has been related to FEV1, BMI, and infection with Burkholderia cepacia complex (BCC). We have assessed the relationship of blood, sputum, and urine inflammatory markers to lung function, BMI, colonization with B cenocepacia (Bc), and patient survival. Thirty-nine stable cystic fibrosis (CF) patients (10 with Bc) were enrolled in a study to determine the effect of alpha-1-antitrypsin on airways inflammation. Pre-treatment measurements were used in this study. Demographics, sputum microbiology, heart rate, oxygen saturation, lung function were recorded. Blood samples were obtained for white blood count (WBC), C-Reactive Protein (CRP), and plasma neutrophil elastase/AAT complexes (pNEC). Neutrophil elastase (NE), neutrophil elastase/AAT complexes (sNEC), interleukin-8 (IL-8), TNF-receptor 1 (sTNFr), and myeloperoxidase (MPO) were measured in sputum and urinary desmosine concentration determined. Patients with Bc had significantly higher levels of pNEC, 332 +/- 91.4 ng/ml (mean +/- SEM) versus 106 +/- 18.2 ng/ml (P = 0.0005) and sNEC, 369 +/- 76.6 ng/ml versus 197 +/- 36.0 ng/ml compared to those who were not. Five deaths were reported at the end of 1 year, (four with Bc) (P = 0.011). Patients who subsequently died had significantly lower lung function FEV1, 1.2 +/- 0.2 L versus 2.0 +/- 0.1 L (P = 0.03) and FVC, 2 +/- 0.3 L versus 3.1 +/- 0.2 L (P = 0.01), compared to those that survived. There was significantly higher NE activity, 3.6 +/- 1.6 U/ml versus 1.5 +/- 0.6 U/ml (P = 0.03), pNEC, 274 +/- 99 ng/ml versus 142 +/- 30 ng/ml (P = 0.05), MPO, 163 +/- 62 mcg/ml versus 54 +/- 6.9 mcg/ml (P = 0.03), and urinary desmosines 108 +/- 19.9 pM/mg creatinine versus 51.1 +/- 3.3 pM/mg creatinine (P = 0.001), in those patients who subsequently died compared to those that survived. These data suggest there is increased neutrophil degranulation in patients infected with Bc and these patients have a poor outcome.
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PMID:The relationship of clinical and inflammatory markers to outcome in stable patients with cystic fibrosis. 1723 89

Serial serum myeloperoxidase was determined in 27 cystic fibrosis patients with chronic endobronchial Pseudomonas aeruginosa infection over the course of 1 y. The effect of repeated courses of antibiotic therapy on mean serum myeloperoxidase levels was significant (p = 0.034). Serial serum myeloperoxidase may help to guide therapy for pulmonary exacerbations.
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PMID:Serum myeloperoxidase in cystic fibrosis patients receiving systemic antibiotics. 1736 36

Lactoperoxidase (LPO) belongs to the mammalian peroxidase family and catalyzes the oxidation of halides, pseudo-halides and a number of aromatic substrates at the expense of hydrogen peroxide. Despite the complex physiological role of LPO and its potential involvement in carcinogenic mechanisms, cystic fibrosis and inflammatory processes, little is known on the folding and structural stability of this protein. We have undertaken an investigation of the conformational dynamics and catalytic properties of LPO during thermal unfolding, using complementary biophysical techniques (differential scanning calorimetry, electron spin resonance, optical absorption, fluorescence and circular dichroism spectroscopies) together with biological activity assays. LPO is a particularly stable protein, capable of maintaining catalysis and structural integrity up to a high temperature, undergoing irreversible unfolding at 70 degrees C. We have observed that the first stages of the thermal denaturation involve a minor conformational change occurring at 40 degrees C, possibly at the level of the protein beta-sheets, which nevertheless does not result in an unfolding transition. Only at higher temperature, the protein hydrophobic core, which is rich in alpha-helices, unfolds with concomitant disruption of the catalytic heme pocket and activity loss. Evidences concerning the stabilizing role of the disulfide bridges and the covalently bound heme cofactor are shown and discussed in the context of understanding the structural stability determinants in a relatively large protein.
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PMID:Lactoperoxidase folding and catalysis relies on the stabilization of the alpha-helix rich core domain: a thermal unfolding study. 1769 26

I order to study the time-course of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) as parameters for monitoring inflammation in cystic fibrosis (CF), we investigated ten patients during both a 14-day intravenous antibiotic treatment and a corresponding self control. Modified Shwachman-Kulczycki score improved significantly (p < 0.008), C-reactive protein (CRP) levels decreased significantly (p < 0.05) during antibiotic treatment, while in the control phase there were no significant differences. Lung function parameters did not change significantly during antibiotic treatment or control phase. Serum MPO concentration (p < 0.006) and peripheral blood neutrophil granulocyte counts (p < 0.04) decreased significantly during antibiotic treatment, but not during the control phase. Sentm ECP concentration showed a tendency to decrease during antibiotic treatment, but this failed to reach significance. In general, sputum concentrations of MPO and ECP Were 500- to 1000-fold higher than in serum. However, neither MPO nor ECP in sputum showed a significan variation over time during antibiotic treatment or control phase. From our data we conclude that: (1) measurements of MPO, neutrophils and CRP in peripheral blood do correlate with clinical parameters such as the modified Shwachman-Kulczycki score; (2) neutrophils and MPO seem to reflect inflammatory changes induced by antibiotic treatment; (3) eosinophils may play a role in CF by an enhanced 'releasability' and (4) Sputum measurements of mediators of inflammation cannot be recommended.
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PMID:Myeloperoxidase and eosinophil cationic protein in serum and sputum during antibiotic treatment in cystic fibrosis patients with Pseudomonas aeruginosa infection. 1847 52

The dual oxidase-thiocyanate-lactoperoxidase (Duox/SCN(-)/LPO) system generates the microbicidal oxidant hypothiocyanite in the airway surface liquid by using LPO, thiocyanate, and Duox-derived hydrogen peroxide released from the apical surface of the airway epithelium. This system is effective against several microorganisms that infect airways of cystic fibrosis and other immunocompromised patients. We show herein that exposure of airway epithelial cells to Pseudomonas aeruginosa obtained from long-term cultures inhibits Duox1-dependent hydrogen peroxide release, suggesting that some microbial factor suppresses Duox activity. These inhibitory effects are not seen with the pyocyanin-deficient P. aeruginosa strain PA14 Phz1/2. We show that purified pyocyanin, a redox-active virulence factor produced by P. aeruginosa, inhibits human airway cell Duox activity by depleting intracellular stores of NADPH, as it generates intracellular superoxide. Long-term exposure of human airway (primary normal human bronchial and NCI-H292) cells to pyocyanin also blocks induction of Duox1 by Th2 cytokines (IL-4, IL-13), which was prevented by the antioxidants glutathione and N-acetylcysteine. Furthermore, we showed that low concentrations of pyocyanin blocked killing of wild-type P. aeruginosa by the Duox/SCN(-)/LPO system on primary normal human bronchial epithelial cells. Thus, pyocyanin can subvert Pseudomonas killing by the Duox-based system as it imposes oxidative stress on the host. We also show that lactoperoxidase can oxidize pyocyanin, thereby diminishing its cytotoxicity. These data establish a novel role for pyocyanin in the survival of P. aeruginosa in human airways through competitive redox-based reactions between the pathogen and host.
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PMID:The Pseudomonas toxin pyocyanin inhibits the dual oxidase-based antimicrobial system as it imposes oxidative stress on airway epithelial cells. 1880 92

The ELR-CXC chemokines play important roles in neutrophilic inflammation. We report in this study that a fully human ELR-CXC chemokine antagonist that we have generated, CXCL8((3-72))K11R/G31P (G31P), has potent anti-inflammatory effects that arise through its actions at multiple levels. G31P inhibited CXCL8-induced chemotactic responses and intracellular Ca(2+) flux in CXCR1-transfected HEK cells and neutrophils, and responses of neutrophils to CXCR2-exclusive ligands. G31P desensitized heterologous G protein-coupled receptors on neutrophils, 52-86% reducing their Ca(2+) flux and chemotactic responses to leukotriene B(4), C5a, and the bacterial tripeptide fMLP. G31P also 60-90% blocked neutrophil chemotactic responses to mediators present in 10 of 12 sputum samples from cystic fibrosis or bronchiectasis subjects with bacterial pneumonia. Moreover, whereas A549 bronchial epithelial cells (which expressed CXCR1) secreted approximately 29,000 pg/ml CXCL8 in response to in vitro endotoxin challenge, G31P reduced this response by up to 98%, presumably by interrupting an autocrine inflammatory loop. The anti-inflammatory effects of G31P extended also to reversing the antiapoptotic influence of ELR-CXC chemokines on neutrophils. That these effects were relevant in vivo was confirmed in a guinea pig model of airway endotoxemia, wherein the human form of G31P >95% blocked neutrophil infiltration into and activation within the airways, as determined by airway levels of the neutrophil primary, secondary, and tertiary granule markers myeloperoxidase, lactoferrin, and matrix metalloproteinase-9, respectively, and the epithelial cell marker matrix metalloproteinase-2. These data suggest that the beneficial effects of ELR-CXC chemokine antagonism arise through effects that occur at multiple levels, including epithelial cells, neutrophils, and alternate G protein-coupled receptors.
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PMID:ELR-CXC chemokine receptor antagonism targets inflammatory responses at multiple levels. 1923 19

A stable isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneously quantifying glutathione (GSH), glutathione disulphide (GSSG) and glutathione sulphonamide (GSA) from biological samples. GSA is a selective product of the reaction of GSH with hypochlorous acid and a potential biomarker of myeloperoxidase activity. GSH was detected as the N-ethylmaleimide alkylated adduct, as formation of this species prevented GSH oxidation occurring during sample processing. Synthesised stable isotope analogues were used as internal standards to accurately quantify each target species. The limit of quantification was determined as being 0.1pmol for each species and excellent linearity was observed over relevant concentration ranges for biological samples. Relative standard deviations were <5% for within-day variation and <10% for between-day variation, except at the lower limit of quantification where they remained <20%. Accuracy was between 82% and 113%. We could detect GSA in neutrophils and endothelial cells treated with hypochlorous acid and in bronchoalveolar lavage fluid from children with cystic fibrosis. This is the first time GSA has been quantified in clinical material and suggests it is formed in vivo. The assay can now be used for investigating GSA as a biomarker of myeloperoxidase activity in inflammatory conditions, and is also applicable to measuring GSH:GSSG molar ratios as a general index of oxidative stress.
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PMID:Simultaneous determination of reduced glutathione, glutathione disulphide and glutathione sulphonamide in cells and physiological fluids by isotope dilution liquid chromatography-tandem mass spectrometry. 1941 84


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