Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.37 (neutrophil elastase)
 4,078 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies from our laboratory indicate that functional, mature neutrophils are essential for interleukin-8 (IL-8)-induced stem cell mobilization. To study a possible role of neutrophils in granulocyte colony-stimulating factor (G-CSF) induced hematopoietic mobilization, we assessed the number of circulating CD34+ cells in healthy allogeneic stem cell donors on days 3, 4, and 5 of mobilization for comparison with the number of peripheral blood neutrophils and the plasma levels of IL-8, Flt3 ligand (FL), matrix metalloproteinase-9 (MMP-9), and human neutrophil elastase (HNE). Thirty-seven of 45 donors required 1 day of apheresis to obtain 5 x 10(6) CD34+/kg recipient body weight (high responders), the remaining 8 donors required 1 extra day of apheresis on day 6 (low responders). On day 5, CD34+ numbers in the blood were significantly highe in high responders (116 x 10(3) +/- 10.4/ml) than in low responders (54.1 x 10(3) +/- 10.3, p < 0.001). In all donors, MMP-9 and HNE levels were increased compared to nonmobilized individuals, but in high responders, plasma MMP-9 levels on days 3-5 of mobilization were substantially higher than in low responders (p < or = 0.02 for MMP-9 and p = 0.89, p = 0.05 and p = 0.52 for HNE on days 3, 4, and 5, respectively). These results are in accordance with the hypothesis that neutrophils play a role in G-CSF-induced mobilization through the release of proteases such as MMP-9 and elastase. No change in plasma levels of IL-8 or Flt3 ligand was observed, suggesting that these cytokines do not play a role in stem cell mobilization. However, because stem cell numbers could not be predicted by proteolytic enzyme levels and/or neutrophil numbers, other undefined factors may be more important.
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PMID:Proteolytic enzyme levels are increased during granulocyte colony-stimulating factor-induced hematopoietic stem cell mobilization in human donors but do not predict the number of mobilized stem cells. 1218 36

Tissue destruction, resulting in emphysema, can be a consequence of several pathologic processes. The current study evaluated the effects of the phosphodiesterase (PDE)4 inhibitor, cilomilast, and other PDE inhibitors on the ability of fibroblasts to degrade extracellular matrix. Using the three-dimensional collagen gel culture system, fibroblasts (HFL-1) were cultured with tumor necrosis factor (TNF)-alpha, known to induce matrix metalloproteinase (MMP) release, and/or neutrophil elastase (NE), which can induce MMP activation. On Day 4, gels containing TNF-alpha and NE were significantly degraded (20.8 +/- 2.9% of original collagen content). Cilomilast (10 micro M) inhibited this degradation (84.4 +/- 8.4%). Amrinone, a PDE3 inhibitor, and zaprinast, a PDE5 inhibitor, had no effect. Gelatin zymography and immunoblotting revealed that fibroblasts cultured with TNF-alpha released increased amounts of latent MMP-1 and -9. The addition of NE resulted in the conversion of MMP-1 and -9 to their active forms, indicative of collagen degradation. Cilomilast inhibited the release of MMP-1 and -9, as well as conversion of MMP-1 to its active form. Using real-time PCR analysis, cilomilast's effect on MMP-1 release was not associated with the proteinase's mRNA expression, suggesting that the inhibition of release is regulated at the post-transcriptional level. These results suggest that cilomilast may be a potentially effective therapeutic agent in diseases characterized by excessive tissue destruction, such as emphysema.
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PMID:Phosphodiesterase 4 inhibitor cilomilast inhibits fibroblast-mediated collagen gel degradation induced by tumor necrosis factor-alpha and neutrophil elastase. 1235 83

The haemorrhagic transformation in ischemic stroke involves disruption of the integrity of the microvascular beds, partially based on the action of matrix metalloproteinases (MMPs). The objective of the present study was to evaluate the contribution of microvascular endothelial cells from human brain (HBECs) to MMPs' expression and regulation under conditions relevant to brain ischemia. MMPs and their inhibitors were examined with zymography, Western-blotting, ELISA and MMP-activity assay in cultured HBECs. Four-hour hypoxia (pO(2)=60 mmHg) elevated the level of MMP-9 in the supernatant of the HBECs and this early response required collagen-matrix. Active oxygen species sustained the increased MMP-9 activity for at least 24 h. In the post-hypoxic period 20 micro mol/L H(2)O(2) caused a 6-fold increase in the specific activity of MMP-9 over the normoxic cells and a comparable effect was exerted by thrombin (50 nmol/L) and leukocyte elastase (10 nmol/L). The role of NF-kappaB, a redox-state sensitive transcription factor, was evaluated with immunofluorescence confocal microscopy and immunoblotting of nuclear and cytoplasmic extracts. The oxidative stress-dependent MMP-9 induction was accompanied by a significant increase in the NF-kappaB localized in the nuclei and these responses were blunted with a proteasome inhibitor (MG132). Consequently, according to our in vitro data HBECs are a source of MMP-9, which is under the control of triggers relevant to the ischemic/reperfused brain (reactive oxygen species, thrombus and inflammation related proteases) and this regulation is partially based on NF-kappaB activation. The reported regulation of endothelium-derived MMP-9 supports its potential involvement in the post-hypoxic disturbances of the cerebral microcirculation.
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PMID:Matrix metalloproteinase-9 expression in post-hypoxic human brain capillary endothelial cells: H2O2 as a trigger and NF-kappaB as a signal transducer. 1295 23

Leukolysin/MT6-MMP is a GPI-anchored matrix metalloproteinase (MMP) primarily expressed by neutrophils. It is stored in intracellular granules at resting state, but rapidly discharged upon stimulations into the extracellular milieu, presumably to promote tissue remodeling or destruction. The proteolytic targets for leukolysin at the inflammatory sites remain unknown. Here, we show that alpha-1-proteinase inhibitor, or alpha1-PI, a known protective shield against destructive serine proteinases, is a physiological target for leukolysin. We show that alpha1-PI failed to accumulate in media conditioned by cells co-expressing alpha1-PI and leukolysin. Purified leukolysin cleaves alpha1-PI efficiently at the Phe376Leu and Pro381Met bonds and the cleaved alpha1-PI lost its anti-proteolytic activity against human neutrophil elastase, cathepsin G (CatG) and proteinase 3 (PR3). In fact, leukolysin preferentially cleaves alpha1-PI when co-incubated with other extracellular molecules such as laminin and gelatin. Kinetically, leukolysin is more active than two known neutrophil MMPs, MMP8 and MMP9, in cleaving and inactivating alpha1-PI. Taken together, these results suggest that neutrophils may mediate tissue destruction by deploying leukolysin to weaken the alpha1-PI protective shield at inflammatory sites.
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PMID:Rapid inactivation of alpha-1-proteinase inhibitor by neutrophil specific leukolysin/membrane-type matrix metalloproteinase 6. 1514 45

To explore possible mechanisms responsible for the absence of cell re-colonization of mural thrombi in aneurysms, we analyzed the release and storage of leukocyte proteases in the most luminal layer versus intermediate and abluminal layers of 10 mural thrombi of human abdominal aortic aneurysms. The luminal layer contained many polymorphonuclear leukocytes (PMNs), which released pro-matrix metalloproteinase (MMP)-9 and MMP-8. Leukocyte elastase was also stored and released by the luminal layer (immunohistochemistry, activity on synthetic substrates, and casein zymography). Acid buffer allowed extraction of leukocyte elastase from the luminal layer, which was inhibited by elastase inhibitors. Casein zymography of luminal extracts and conditioned medium from formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMNs exhibited a similar lysis pattern, corresponding to elastase activity. Smooth muscle cell (SMC) seeding resulted in colonization of the intermediate thrombus layer ex vivo but not of the luminal layer. Extracts of the luminal layer induced loss of anchorage of both cultured human smooth muscle cells and stromal cells of bone marrow origin (anoikis). This anoikis was prevented by preincubation of the extracts with serine protease inhibitors. Moreover, adhesion of human SMCs and stromal bone marrow cells on fibrin gels was strongly inhibited when the gel was preincubated with pure elastase, medium of fMLP-stimulated PMNs, or extracts of luminal layers of mural thrombi. This loss of cell anchorage was prevented by the preincubation of the medium or extracts with alpha(1)-antitrypsin, but not when alpha(1)-antitrypsin was added after binding of elastase to the fibrin gel. In conclusion, elastase released by PMNs trapped within the mural thrombus impairs the spontaneous anchorage of mesenchymal cells to a fibrin matrix. This phenomenon could be one mechanism by which cellular healing of the mural thrombus in aneurysms is prevented.
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PMID:Role of leukocyte elastase in preventing cellular re-colonization of the mural thrombus. 1516 42

Proteases exert control over cell behavior and affect many biological processes by making proteolytic modification of regulatory proteins. The purpose of this paper is to describe novel, important functions of matrix metalloproteinase (MMP)-26. alpha1-Antitrypsin (AAT) is a serpin, the primary function of which is to regulate the activity of neutrophil/leukocyte elastase. Insufficient antiprotease activity because of AAT deficiency in the lungs is a contributing factor to early-onset emphysema. We recently discovered that AAT is efficiently cleaved by a novel metalloproteinase, MMP-26, which exhibits an unconventional PH(81)CGVPD Cys switch motif and is autocatalytically activated in cells and tissues. An elevated expression of MMP-26 in macrophages and polymorphonuclear leukocytes supports the functional role of MMP-26 in the AAT cleavage and inflammation. We have demonstrated a direct functional link of MMP-26 expression with an estrogen dependency and confirmed the presence of the estrogen-response element in the MMP-26 promoter. Immunostaining of tumor cell lines and biopsy specimen microarrays confirmed the existence of the inverse correlations of MMP-26 and AAT in cells/tissues. An expression of MMP-26 in the estrogen-dependent neoplasms is likely to contribute to the inactivation of AAT, to the follow-up liberation of the Ser protease activity, and because of these biochemical events, to promote matrix destruction and malignant progression. In summary, we hypothesize that MMP-26, by cleaving and inactivating the AAT serpin, operates as a unique functional link that regulates a coordinated interplay between Ser and metalloproteinases in estrogen-dependent neoplasms.
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PMID:Matrix metalloproteinase-26 is associated with estrogen-dependent malignancies and targets alpha1-antitrypsin serpin. 1557 74

Matrix metalloproteinases (MMPs) degrade extracellular matrix and are implicated in causing airway damage in chronic inflammatory lung diseases, including cystic fibrosis (CF). Our primary objective was to examine the relationship between matrix metalloproteinase-9 (MMP-9) and pulmonary function, as measured by forced expiratory volume in 1 sec (FEV1), in children with CF. We measured MMP-9 and its natural tissue inhibitor of metalloproteinase-1 (TIMP-1) in induced sputum from 18 clinically stable CF children with normal to mildly abnormal lung function and 7 healthy control children. Measures of airway inflammation from induced sputum included cell counts and differentials, interleukin-8 (IL-8), neutrophil elastase, MMP-9, and TIMP-1. Infection was assessed through quantitative bacterial counts. Induced sputum levels of MMP-9 and TIMP-1 were significantly increased in children with CF compared with healthy controls. Also, the MMP-9/TIMP-1 molar ratio was higher in the CF group. Among CF children, there was a significant inverse relationship between MMP-9 and FEV1. In addition, sputum MMP-9 and TIMP-1 concentrations significantly correlated with total white cells and neutrophils, IL-8, and neutrophil elastase. Neither MMP-9 nor TIMP-1 correlated with airway infection. We conclude that clinically stable CF children with normal to mildly abnormal lung function have an increased burden of MMP-9 in their airways. The observed relationships of MMP-9 with lung function and other measures of airway inflammation suggest that this enzyme may be a useful marker of airway injury and airflow obstruction in persons with CF.
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PMID:Induced sputum matrix metalloproteinase-9 correlates with lung function and airway inflammation in children with cystic fibrosis. 1603 25

Neutrophil-derived proteases such as neutrophil elastase (NE) and matrix metalloproteinase (MMP) are implicated in the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD). In this study, the effects of selective phosphodiesterase (PDE) inhibition on NE and MMP-9 release, as well as Myeloperoxidase (MPO) activity and integrin-mediated neutrophil adhesion to human umbilical vein endothelial cells (HUVECs), were investigated. Human neutrophils were treated with PDE inhibitors (10(-11)-10(-4)M) in the absence and presence of TNF-alpha (tumour necrosis factor) (100 U ml(-1)) for 30 min, prior to fMLP activation. After 45 min, the cells were removed and NE, MPO and MMP-9 release assessed. In the adhesion studies, the neutrophils were radio-labelled with 51Cr, stimulated and immediately transferred to cultured HUVEC monolayers for 30 min, prior to assessment of adhesion. TNF-alpha (100 U ml(-1)) acted synergistically with fMLP in stimulating azurophil degranulation with respect to both MPO activity (P<0.01) and NE release (P<0.01). In contrast, an additive effect was observed with TNF-alpha and fMLP with regard to MMP-9 release and neutrophil adhesion to HUVECs. The PDE4 inhibitors, roflumilast, roflumilast N-oxide, cilomilast and rolipram significantly suppressed MPO, NE and MMP-9 release in both the presence and absence of TNF-alpha (P<0.05; n=6-10) and also reduced neutrophil adhesion to HUVECs. In contrast, milrinone, a PDE3 inhibitor and the non-selective PDE inhibitor, theophylline did not inhibit azurophil degranulation under any of the experimental conditions. These data provide further evidence that selective PDE4 isoenzyme inhibitors can inhibit neutrophil degranulation, effects not shared by PDE3 inhibitors or theophylline.
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PMID:The effect of selective phosphodiesterase isoenzyme inhibition on neutrophil function in vitro. 1564 51

beta-Lactams, a well known class of antibiotics, have been investigated as inhibitors of the disruptive protease released by inflammatory cells, leukocyte elastase (LE). We have synthesized a new beta-lactam with an N-linked galloyl moiety, the latter identified as strategic in conferring anti-LE properties to some flavonols. This N-galloyl-derivative beta-lactam inhibits the LE activity with a K(i) of 0.7 microM, whereas it exerts weak activity against cathepsin G and protease-3 (IC(50) > 100 microM), and matrix metalloproteinase (MMP)-2 and MMP-9. Without affecting chemotactic response and viability of polymorphonuclear (PMN) leukocytes, the compound efficiently restrains their chemoinvasion (IC(50) of 1-2 microM) blocking the LE-triggered activation of pro-MMP-9, instrumental to extravasation. Daily i.p. injection of compound enhances resolution in a pulmonary inflammation model, significantly reducing consequent fibrosis. These results indicate that the new beta-lactam is a potent anti-inflammatory compound with therapeutic potential.
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PMID:Inhibition of leukocyte elastase, polymorphonuclear chemoinvasion, and inflammation-triggered pulmonary fibrosis by a 4-alkyliden-beta-lactam with a galloyl moiety. 1624 67

Hyperforin (Hyp), a polyphenol-derivative of St. John's wort (Hypericum perforatum), has emerged as key player not only in the antidepressant activity of the plant but also as an inhibitor of bacteria lymphocyte and tumor cell proliferation, and matrix proteinases. We tested whether as well as inhibiting leukocyte elastase (LE) activity, Hyp might be effective in containing both polymorphonuclear neutrophil (PMN) leukocyte recruitment and unfavorable eventual tissue responses. The results show that, without affecting in vitro human PMN viability and chemokine-receptor expression, Hyp (as stable dicyclohexylammonium salt) was able to inhibit in a dose-dependent manner their chemotaxis and chemoinvasion (IC50=1 microM for both); this effect was associated with a reduced expression of the adhesion molecule CD11b by formyl-Met-Leu-Phe-stimulated neutrophils and block of LE-triggered activation of the gelatinase matrix metalloproteinase-9. PMN-triggered angiogenesis is also blocked by both local injection and daily i.p. administration of the Hyp salt in an interleukin-8-induced murine model. Furthermore, i.p. treatment with Hyp reduces acute PMN recruitment and enhances resolution in a pulmonary bleomycin-induced inflammation model, significantly reducing consequent fibrosis. These results indicate that Hyp is a powerful anti-inflammatory compound with therapeutic potential, and they elucidate mechanistic keys.
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PMID:Hyperforin blocks neutrophil activation of matrix metalloproteinase-9, motility and recruitment, and restrains inflammation-triggered angiogenesis and lung fibrosis. 1728 34


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