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:3.4.21.37 (neutrophil elastase)
4,078 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10-60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neutrophil elastase potentiates cathepsin G-induced platelet activation. 133 49

Regenerated cellulosic membranes (CU) induced the aggregation of plasma-free human neutrophils when recirculated in a dynamic model of dialysis without the patient on the circuit. Neutrophil aggregation was linked to the production of PAF by these cells. In the absence of detectable PAF production, no neutrophil aggregation occurred, as observed during recirculation with polymethylmethacrylate (PMMA) membranes. With polycarbonate (PC), PAF production and aggregation of neutrophils were both almost half the values with CU. PAF production was studied in ten hemodialysis (HD) patients tested twice with CU and once with PC and PMMA membranes. PAF was extracted in the venous blood during filling of the dialyser for 9/20 of patients with CU (3.1 +/- 2.9 ng/ml, mean +/- 1 S.D.) a membrane that induced marked leukopenia (greater than 50% of basal values at 15 min), C3a des Arg generation (greater than 500% at 5 min), and plasma levels of the elastase-alpha 1-proteinase inhibitor complex (greater than 500% at the end of HD). Membranes such as PC and PMMA showing intermediate or low potential to induce leukopenia and C3a des Arg generation, respectively, did not trigger the production and release of PAF in detectable amounts at any interval. However, with PMMA, plasma neutrophil elastase was significantly higher than baseline at the end of dialysis. These levels were not significantly different (p less than 0.05) from those observed with CU and PC membranes.
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PMID:The production of platelet-activating factor during hemodialysis. 261 57

Complex mechanisms regulate sequestration, retention and migration of neutrophils in the lung. Neutrophils can migrate into the lung without producing significant damage under some circumstances, whereas at other times great structural alteration occurs. A potential explanation lies in the phenomenon of priming, a state of altered responsivity of neutrophils. A wide variety of molecules are able to induce this higher degree of responsiveness including PAF, TNF, GM-CSF, and IL-1. Enhanced cellular responses include secretion, adhesion and synthetic function. Unprimed neutrophils can migrate through lung tissues, secreting but little of their contents, in the context of "normal" inflammatory response. On the other hand neutrophils primed before the emigration phase, injury to the tissue they are migrating through would be likely by virtue of releasing toxic mediators. One of these mediators is neutrophil elastase, a potent protease. It is the purpose of this review to highlight the duality function of neutrophils as (i) one of the bodies highly effective host defense weapons and (ii) mediator of destruction and host defense impairment in the lung by releasing mediators such as neutrophil elastase.
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PMID:Consequences of unbalanced protease in the lung: protease involvement in destruction and local defense mechanisms of the lung. 848 May 53

Multiple organ dysfunction syndrome (MODS) is a critical condition developing in the patients under overwhelming surgical insults such as a major surgery, severe trauma, extensive burn, and systemic sepsis. The host response to those surgical insults is the main pathogenetic factor contributing to the development of shock and MODS seen in surgical patients. The proinflammatory cytokines, TNF-alpha (TNF) and interleukin-1 beta (IL-1), are known to play a pivotal role in the pathogenetic mechanisms of MODS. In response to surgical insults, macrophages produce and release TNF and IL-1 which subsequently induce the production of other cytokines (IL-6, IL-8, etc.) and other endogenous chemical mediators (growth factors, adhesion molecules, complement cleavage products, thrombin, eicosanoids, PAF, nitric oxides, oxygen-free radicals, granulocyte elastase, etc.) The resultant systemic inflammation may develop into shock and MODS when the primary insults are overwhelming (early MODS) or a second inflammatory insult such as sepsis triggers an exaggerated inflammation. In the patients suffering from MODS, a systemic release of various cytokines is not properly regulated, and the high blood levels of the proinflammatory cytokines induce an autodestructive generalized inflammatory reaction. This condition is termed "Cytokine Storm" by the author. In the cytokine storm, not only proinflammatory cytokines but also anti-inflammatory cytokines are elevated in the blood stream. With the recent understanding of the biological and pathological roles of cytokines and other mediators, a new therapeutic strategy has been developed. In addition to the reduction of the surgical insults, a variety of anti-cytokine therapy and anti-mediator therapy has been tested in an attempt to prevent or treat the life-threatening MODS.
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PMID:[Cytokine storm in the pathogenesis of multiple organ dysfunction syndrome associated with surgical insults]. 894 Jun 90

In an accompanying study, we described the presence of intact fibronectin, a large adhesive molecule, in the specific granules of blood PMNs. Secretion of fibronectin by blood PMNs is poorly understood, and the fate of this fibronectin is practically unknown. In the present study we demonstrate that nanomolar concentrations of phorbol ester or the chemoattractants fMLP, PAF, and LTB4 induce fibronectin secretion from blood PMNs. Phorbol ester induced secretion of approximately 85% of the total fibronectin content, as well as expression of small amounts on the cell surface of the activated PMNs. Secreted fibronectin was proteolytically cleaved and, after 20 min, four major fragments of 150, 120, 90, and 80 kDa containing a midchain epitope were identified by Western blot analysis. Kinetic studies indicated that fibronectin was rapidly secreted as an intact molecule and that proteolysis started within minutes and proceeded for at least 1 h. If cells were removed after 5 min TPA treatment, no further proteolysis of the secreted fibronectin was observed, indicating participation of cell-bound proteinases. From a cocktail of proteinase inhibitors, PMSF was the most active in suppressing fibronectin proteolysis. Studies with specific peptidyl inhibitors of human leukocyte elastase and cathepsin G, major serine proteinases of PMNs, demonstrated some inhibition with the cathepsin G inhibitor, while the human leukocyte elastase inhibitor almost completely abolished fibronectin proteolysis. A monoclonal antibody to the elastase had a similar effect. The results indicate that intact fibronectin is a secretory product of blood PMNs and that this endogenous adhesive molecule is within minutes extracellularly processed by cell surface-bound elastase.
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PMID:Endogenous fibronectin of blood polymorphonuclear leukocytes: stimulus-induced secretion and proteolysis by cell surface-bound elastase. 918 73

We have recently identified hyperforin, a lipophilic constituent of the herb Hypericum perforatum (St. John's wort), as a dual inhibitor of the proinflammatory enzymes cyclooxygenase-1 and 5-lipoxygenase. The aim of the present study was to further elucidate antiinflammatory properties and respective targets of hyperforin. We found that hyperforin inhibited the generation of reactive oxygen species (ROS) as well as the release of leukocyte elastase (degranulation) in human isolated polymorphonuclear leukocytes (PMNL), challenged by the G protein-coupled receptor (GPCR) ligand N-formyl-methionyl-leucyl-phenylalanine (fMLP) with an IC 50 approximately equal 0.3 microM. When PMNL were stimulated with phorbol-12-myristate-13-acetate (PMA) or ionomycin, hyperforin (up to 10 microM) failed to inhibit ROS production and elastase release, respectively. Moreover, hyperforin blocked receptor-mediated Ca(2+) mobilization ( IC 50 approximately equal 0.4 and 4 microM, respectively) in PMNL and monocytic cells, and caused a rapid decline of the intracellular Ca(2+) concentration in resting cells. In contrast, the Ca(2+) influx induced by ionomycin or thapsigargin was not suppressed. Comparative studies with the specific phospholipase C inhibitor U-73122 and hyperforin revealed similarities between both compounds. Thus, U-73122 and hyperforin blocked fMLP- and PAF-induced Ca(2+) mobilization, ROS formation, and elastase release, but failed to suppress these responses when cells were stimulated by PMA or ionomycin. Also, both compounds rapidly decreased basal Ca(2+) levels in resting cells and led to a rapid decline of the Ca(2+) elevations evoked by fMLP or PAF. Our data suggest that hyperforin targets component(s) within G protein signaling cascades that regulate Ca(2+) homeostasis, coupled to proinflammatory leukocyte functions.
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PMID:Suppression of receptor-mediated Ca2+ mobilization and functional leukocyte responses by hyperforin. 1504 70

Circulating human neutrophils from patients with severe inflammatory disorders such as erysipelas and sepsis are specifically desensitized to complement factor C5a stimulation but not to stimulation with other stimuli like N-formyl-methionyl-leucyl-phenylalanine (FMLP), interleukin-8 (IL-8), leukotriene B4 (LTB4), or platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). In this study, we raised the question whether factors released from polymorphonuclear leukocytes (PMNs) can specifically down-regulate C5a-dependent neutrophil functions. When neutrophils were preincubated with either neutrophil lysates or neutrophil degranulation supernatants, a complete inhibition of C5a-stimulated beta-glucuronidase release and chemotaxis could be observed, whereas FMLP-, IL-8-, LTB4- or PAF-dependent functions were not affected. Serine protease inhibitors like phenylmethylsulfonyl fluoride, antileukoprotease, or elafin abolished this effect. High-performance liquid chromatography of neutrophil degranulation supernatants revealed pronounced inhibition of C5a-dependent neutrophil functions in fractions exerting elastase or cathepsin G activity, but not in fractions exerting proteinase 3 activity. Using purified human leukocyte elastase (HLE), C5a responses like intracellular calcium influx, beta-glucuronidase release, and chemotaxis were also specifically inhibited. Our experiments show that the release of HLE or cathepsin G from neutrophils specifically down-regulates the responsiveness of neutrophils to C5a. Elastase and cathepsin G may therefore play an important role in the down-regulation of acute inflammation.
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PMID:Human leukocyte elastase and cathepsin G are specific inhibitors of C5a-dependent neutrophil enzyme release and chemotaxis. 1514 22

Proteinaceous inhibitors with high inhibitory activities against human neutrophil elastase (HNE) were found in seeds of the Tamarind tree (Tamarindus indica). A serine proteinase inhibitor denoted PG50 was purified using ammonium sulphate and acetone precipitation followed by Sephacryl S-300 and Sephadex G-50 gel filtration chromatographies. Inhibitor PG50 showed a Mr of 14.9 K on Sephadex G-50 calibrated column and a Mr of 11.6 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PG50 had selective activity while cysteine proteinases (papain and bromelain) and serine proteinases (porcine pancreatic elastase and bovine chymotrypsin) were not inhibited, it was strongly effective against serine proteinases such as bovine trypsin and isolated human neutrophil elastase. The IC50 value was determined to be 55.96 microg.mL-1. PG50 showed neither cytotoxic nor haemolytic activity on human blood cells. After pre-incubation of PG50 with cytochalasin B, the exocytosis of elastase was initiated using PAF and fMLP. PG50 exhibited different inhibition on elastase release by PAF, at 44.6% and on release by fMLP, at 28.4%. These results showed that PG50 preferentially affected elastase release by PAF stimuli and this may indicate selective inhibition on PAF receptors.
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PMID:A serine proteinase inhibitor isolated from Tamarindus indica seeds and its effects on the release of human neutrophil elastase. 1582 May

Several species in the genus Arnica have been used in traditional medicine to treat inflammatory-related disorders. Extracts of twelve Arnica species and two species closely related to arnica ( Layia hieracioides and Madia sativa) were investigated for inhibition of human neutrophil elastase release and inhibition of transcription factor NF-kappaB. Statistical analyses reveal significant differences in inhibitory capacities between extracts. Sesquiterpene lactones of the helenanolide type, of which some are known inhibitors of human neutrophil elastase release and NF-kappaB, are present in large amounts in the very active extracts of A. montana and A. chamissonis. Furthermore, A. longifolia, which has previously not been investigated, shows a high activity similar to that of A. montana and A. chamissonis in both bioassays. Sesquiterpene lactones of the xanthalongin type are present in large amounts in A. longifolia and other active extracts and would be interesting to evaluate further. COX-2:cyclooxygenase 2 EMSA:electrophoretic mobility shift assay fMLP: N-formyl-methionyl-leucyl-phenylalanine HaCaT:human keratinocyte HNE:human neutrophil elastase IkappaB:inhibitory subunit of kappaB iNOS:inducible nitric oxide synthase NF-kappaB:nuclear factor kappaB PAF:platelet activating factor STL:sesquiterpene lactone TNF-alpha:tumor necrosis factor alpha.
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PMID:Screening for anti-inflammatory activity of 12 Arnica (Asteraceae) species assessed by inhibition of NF-kappaB and release of human neutrophil elastase. 1897 64

Seeds from legumes including the Gilcine max are known to be a rich source of protease inhibitors. The soybean Kunitz trypsin inhibitors (SKTIs) have been well characterised and have been found to exhibit many biological activities. However their effects on inflammatory diseases have not been studied to date. In this study, SKTI was purified using anion exchange chromatography using a Resource Q column. The purified protein was able to inhibit human neutrophil elastase (HNE) and bovine trypsin. Purified SKTI inhibited HNE with an IC(50) value of 8mug or 0.3nM. At this concentration SKTI showed neither cytotoxic nor haemolytic effects on human blood cell populations. SKTI showed no deleterious effects on organs, blood cells or the hepatic enzymes ALT and AST in the mouse model of acute systemic toxicity. Human neutrophils incubated with SKTI released less HNE than control neutrophils when stimulated with PAF or fMLP (83.1% and 70% respectively). These results showed that SKTI affected both pathways of elastase release by PAF and fMLP stimuli, suggesting that SKTI is an antagonist of fMLP/PAF receptors. In an in vivo mouse model of LPS acute lung injury, SKTI significantly suppressed the inflammatory effects caused by elastase in a dose-dependent manner. Histological sections stained by hematoxylin/eosin confirmed this decrease in inflammation. These results showed that SKTI could be used as a pharmacological agent for the therapy of many inflammatory diseases.
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PMID:New properties of the soybean trypsin inhibitor: Inhibition of human neutrophil elastase and its effect on acute pulmonary injury. 2062 84


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