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)

To examine the course of physiologic interactions between extravasating neutrophils and the subendothelial basement membrane, a model of the venular vessel wall was constructed by culturing human umbilical vein endothelial cells on a collagen matrix. After 21 d in culture, the endothelial cell monolayer displayed in vivo-like intercellular borders and junctions, deposited a single-layered, continuous basement membrane that was impenetrable to colloidal particles, and supported neutrophil extravasation in a physiologic manner. Using this model, we demonstrate that neutrophil transmigration in a plasma milieu was associated with a significant disruption of the retentive properties of the basement membrane in the absence of discernable morphologic changes. The loss of basement membrane integrity associated with neutrophil diapedesis was not dependent on neutrophil elastase or cathepsin G and was resistant to inhibitors directed against neutrophil collagenase, gelatinase, and heparanase. Despite the fact that this loss in matrix integrity could not be prevented, basement membrane defects were only transiently expressed before they were repaired by the overlying endothelium via a mechanism that required active protein and RNA synthesis. These data indicate that neutrophil extravasation and reversible basement membrane disruption are coordinated events that occur as a consequence of vessel wall transmigration.
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PMID:Disruption of the subendothelial basement membrane during neutrophil diapedesis in an in vitro construct of a blood vessel wall. 270 27

Collagenase from human polymorphonuclear leukocytes (neutrophil collagenase) attacks collagen type II in solution at a rate intermediate to those of type I and III collagens. This enzyme alone is not able to initiate degradation of native human articular cartilage. If the cartilage is first treated with leukocyte elastase, collagenase slowly degrades collagen. Confirming earlier findings by other investigators, elastase has a dual action on cartilage: The enzyme removes proteoglycans, thus demasking collagen fibers and giving collagenase access to them, and solubilizes collagen at a sizable rate. Although neutrophil collagenase cleaves collagen type II in solution at a high rate, the native, cross-linked status of collagen in cartilage makes it a relatively poor substrate for this enzyme. On a weight by weight scale, elastase and collagenase display about the same collagenolytic potential on human articular cartilage. The elastase/collagenase system from human polymorphonuclear leukocytes could represent a cooperative proteolytic complex in the destruction of cartilage in rheumatoid arthritis.
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PMID:Action of collagenase and elastase from human polymorphonuclear leukocytes on human articular cartilage. 629 13

The potential role of neutrophil elastase in causing lung damage and exacerbating the inflammatory response in cystic fibrosis (CF) has received considerable attention. Although another potent neutrophil-derived enzyme, collagenase, is implicated in tissue destruction in several interstitial lung disorders, there has been no reference to this enzyme in CF. The objective of this study was to determine whether neutrophil collagenase is present in active form in CF sputum and, if so, whether it is related to disease severity. High levels of active collagenase were detected in sputum from patients with CF, and the majority of the enzyme present was of neutrophil origin. In a group of 16 patients with CF, negative relations between sputum collagenase activity and Shwachman score (r = -0.55, p < 0.05) and FEV1 (r = -0.59, p < 0.02) were noted, indicating an association between high collagenase activity and severity of disease. A positive correlation was observed between sputum collagenase and elastase activity (r = 0.62, p < 0.05). These results suggest that both neutrophil elastase and collagenase may play a significant role in lung destruction in CF.
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PMID:Neutrophil collagenase in sputum from patients with cystic fibrosis. 808 57

The concentration of doxycycline required to inhibit 50% (50% inhibitory concentration for serpinase activity) of alpha-1-antitrypsin degradation by purified neutrophil collagenase was found to be approximately 20 microM, a value similar to the 50% inhibitory concentration of doxycycline required to inhibit collagen degradation by neutrophil collagenase. Doxycycline also efficiently inhibited phorbol myristate acetate-triggered neutrophil-mediated degradation of alpha-1-antitrypsin. This suggests that doxycycline can protect alpha-1-antitrypsin from collagenase and gelatinase in the presence of other proteases and biologically active molecules that are released by triggered neutrophils. The protection of a body's alpha-1-antitrypsin shield from serpinolytic activity of collagenase and matrix metallproteinases can result in inhibition of serine proteases such as neutrophil elastase. Tetracyclines may thus protect matrix constituents from a wider spectrum of neutral proteases than previously recognized, not just from the matrix metalloproteinases collagenase and gelatinase.
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PMID:Doxycycline in the protection of serum alpha-1-antitrypsin from human neutrophil collagenase and gelatinase. 838 19

Interstitial collagenases, members of the matrix metalloproteinase family, are key initiators of collagen destruction during various disorders such as rheumatoid arthritis. Recently interstitial collagenases were found to efficiently degrade an additional non-collagenous substrate, the serum alpha-1-antitrypsin (AAT also called alpha-1-proteinase inhibitor or serpin). Serpins are major endogenous inhibitors of serine proteinases, particularly neutrophil elastase. Of relevance to neutrophil-mediated collagen degradation, the tetracycline family of antibiotics are now known to inhibit inhibit mammalian collagenases by a mechanism unrelated to their antimicrobial activity. This study identifies an additional mechanism by which tetracyclines may retard tissue breakdown during inflammatory diseases. Doxycycline, added to the reaction mixture as in concentrations as low as 10 microM, which correspond to levels of the drug readily achieved in vivo, produced detectable inhibition of serpinase activity of neutrophil collagenase, although levels of 50-100 microM or greater were required to reduce AAT degradation more than 75%. The concentration of doxycycline to inhibit 50% (IC50 of serpinase activity) of AAT degradation by neutrophil collagenase was found to approximate 20 microM, a value similar to the IC50 for doxycycline required to inhibit collagen degradation by neutrophil collagenase. Doxycycline was also found to inhibit at cell level neutrophil-mediated degradation of AAT. The protection of bodies' AAT-shield from serpinolytic activity of collagenase would result in inhibition of serine proteinases such as neutrophil elastase. Tetracyclines may thus protect matrix constituents from a wider spectrum of neutral proteases than previously recognized, not just from the matrix metalloproteinases collagenase and gelatinase.
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PMID:Doxycycline protects serum alpha-1-antitrypsin from human neutrophil collagenase. 845 33

The aim of this study was to investigate the extracellular degrading proteolytic cascade proteins referred to as matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9, membrane-type matrix metalloproteinase-1 (MT1-MMP), tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), TIMP-2, neutrophil elastase, and alpha1-antitrypsin in human pulmonary emphysema. Localization of MMP-1, MMP-2, MMP-8, MMP-9, MT1-MMP, TIMP-1, and TIMP-2 was verified by immunohistochemical analysis. The results of our study indicated that the immunoreactivity of MMP-1, MMP-8, MMP-9, and TIMP-1 was absent, whereas MT1-MMP and MMP-2 were mainly observed in pneumocytes, fibroblasts, and alveolar macrophages. Although MT1-MMP and MMP-2 were observed both in emphysematous and normal lung tissue, these immunoreactivities were intense in the emphysematous samples. The presence of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 was confirmed at mRNA level by reverse transcription-PCR analysis and enzyme immunoassay (EIA). However, the only statistical difference that was observed was in MMP-2 and MMP-9 (MMP-2: emphysematous samples, 19.1+/-2.1 versus control samples, 5.2+/-0.60 microg/g protein, p < 0.05; MMP-9: emphysematous samples, 18.4+/-5.6 versus control samples, 8.1+/-2.7 microg/g protein, p < 0.05). Results of the neutrophil elastase as analyzed by EIA, and alpha1-antitrypsin levels as detected by laser nephelometric immunoassay, indicated no statistical difference between the emphysematous and control groups. In addition to the presence of mRNA levels, the level of MT1-MMP according to immunoblot analysis increased in the emphysematous samples. Gelatin zymographic analysis confirmed the presence of both pro and active forms of MMP-2, and the increased ratio of the active form of MMP-2 in emphysematous samples (25.9%+/-2.0% versus 11.2%+/-3.3%, p < 0.05), indicated in situ activation of MMP-2 by MT1-MMP. Elastin zymographic analysis showed elastolytic activity by MMP-2 and MMP-9 but not the reported band of macrophage metalloelastase (MMP-12). The data suggest that the MT1-MMP/MMP-2/TIMP-2 system plays a significant role in the MMP-mediated extracellular matrix degradation and tissue remodeling of emphysematous lungs, and thus may contribute to the weakening of lung parenchyma and lead to the formation of emphysema.
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PMID:Matrix metalloproteinase-mediated extracellular matrix protein degradation in human pulmonary emphysema. 975 52

Complement receptor 1 (CR1) is cleaved from the surface of polymorphonuclear cells (PMN) in the membrane-proximal region to yield a soluble fragment (sCR1) that contains the functional domains. The enzymes involved in this cleavage are produced by the PMN itself, since in vitro stimulation of purified PMN is followed by sCR1 release. Purified human neutrophil elastase (HNE) cleaved CR1 from erythrocytes and urinary vesicles originating from podocytes and enhanced tenfold the cleavage of CR1 from activated PMN. The largest fragment released from PMN by HNE was identical in size to CR1 shed spontaneously. The CR1 fragments cleaved from erythrocytes were functional. The shedding of sCR1 by activated PMN was inhibited by phenylmethylsulfonyl fluoride (80 +/- 10%), alpha1-antiprotease (50 +/- 5%) and elafin (60 +/- 5%). Furthermore the cleavage was blocked by the metalloprotease inhibitor 1,10-phenanthroline (70 +/- 6 %) as well as by a monoclonal antibody against human neutrophil collagenase MMP8 (40 +/- 10%). Maximal inhibition of sCR1 shedding was obtained by a combination of 1,10-phenanthroline with elafin (86 +/- 6%). These inhibitors had no effect on L-selectin shedding, indicating that the cleavage of CR1 was specific. In conclusion, elastase or elastase-like activity may be responsible for the shedding of functional sCR1 in vivo, and this activity is controlled by the local release of PMN metalloproteases and alpha1antiprotease.
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PMID:Elastase and metalloproteinase activities regulate soluble complement receptor 1 release. 1055 32

Humans express three distinct collagenases, MMP-1, MMP-8, and MMP-13, that initiate degradation of fibrillar type I collagen. We have previously reported that ultraviolet irradiation causes increased expression of MMP-1, but not MMP-13, in keratinocytes and fibroblasts in human skin in vivo. We report here that ultraviolet irradiation increases expression of MMP-8 in human skin in vivo. Western analysis revealed that levels of the full-length, 85 kDa proenzyme form of MMP-8 increased significantly within 8 h post ultraviolet irradiation (2 minimal erythema doses). Increased full-length MMP-8 protein was associated with infiltration into the skin of neutrophils, which are the major cell type that expresses MMP-8. Immunofluorescence revealed coexpression of MMP-8 and neutrophil elastase, a marker for neutrophils. Immunohistology demonstrated MMP-8 expression in neutrophils in the papillary dermis between 4 and 8 h post ultraviolet irradiation, and in the epidermis at 24 h post radiation. MMP-8 mRNA expression was not detected in nonirradiated or ultraviolet-irradiated human skin, indicating that increased MMP-8 following ultraviolet irradiation resulted from preexisting MMP-8 protein in infiltrating neutrophils. Pretreatment of skin with the glucocorticoid clobetasol, but not all-trans retinoic acid, significantly blocked ultraviolet-induced increases in MMP-8 protein levels, and neutrophil infiltration. In contrast, all-trans retinoic acid and clobetasol were equally effective in blocking ultraviolet induction of MMP-1 and degradation of collagen in human skin in vivo. Taken together, these data demonstrate that ultraviolet irradiation increases MMP-8 protein, which exists predominantly in a latent form within neutrophils, in human skin in vivo. Although ultraviolet irradiation induces both MMP-1 and MMP-8, ultraviolet-induced collagen degradation is initiated primarily by MMP-1, with little, if any, contribution by MMP-8.
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PMID:Ultraviolet irradiation increases matrix metalloproteinase-8 protein in human skin in vivo. 1151 Dec 97

The naturally occurring neutrophil elastase inhibitors, alpha1-proteinase inhibitor (alpha1PI), secretory leukocyte proteinase inhibitor (SLPI), and elafin, are potential therapeutic agents in the treatment of neutrophil-mediated lung disease. However alpha1PI has been shown to be susceptible to inactivation by matrix metalloproteinases (MMPs) released by neutrophils, particularly neutrophil collagenase (MMP-8). The aim of this study was to determine if SLPI and elafin are similarly susceptible to degradation by this neutrophil-specific MMP. The effect of MMP-8 on SLPI and elafin was assessed by determining the neutrophil elastase inhibitory capacity (NEIC) and electrophoretic protein profile of both inhibitors following exposure to purified MMP-8. As a positive control, the effect of MMP-8 alpha1PI was assessed in parallel. Although treatment of alpha1PI with MMP-8 resulted in a significant decrease in its NEIC (P = .025), no similar decrease was observed with SLPI or elatin. Electrophoretic analysis confirmed digestion of alpha1PI by MMP-8 but no digestion of either SLPI or elafin was observed. These results demonstrate that SLPI and elafin are resistant to proteolytic inactivation by MMP-8, a property that may enhance their therapeutic application in neutrophil-mediated inflammatory lung disease.
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PMID:Secretory leukocyte proteinase inhibitor and elafin are resistant to degradation by MMP-8. 1186 25

Mannose-binding lectin (MBL) plays a critical role in innate immunity. Point mutations in the collagen-like domain (R32C, G34D, or G37E) of MBL cause a serum deficiency, predisposing patients to infections and diseases such as rheumatoid arthritis. We examined whether MBL mutants show enhanced susceptibility to proteolysis by matrix metalloproteinases (MMPs), which are important mediators in inflammatory tissue destruction. Human and rat MBL were resistant to proteolysis in the native state but were cleaved selectively within the collagen-like domain by multiple MMPs after heat denaturation. In contrast, rat MBL with mutations homologous to those of the human variants (R23C, G25D, or G28E) was cleaved efficiently without denaturation in the collagen-like domain by MMP-2 and MMP-9 (gelatinases A and B) and MMP-14 (membrane type-1 MMP), as well as by MMP-1 (collagenase-1), MMP-8 (neutrophil collagenase), MMP-3 (stromelysin-1), neutrophil elastase, and bacterial collagenase. Sites and order of cleavage of the rat MBL mutants for MMP-2 and MMP-9 were: Gly(45)-Lys(46) --> Gly(51)-Ser(52) --> Gly(63)-Gln(64) --> Asn(80)-Met(81) which differed from that of MMP-14, Gly(39)-Leu(40) --> Asn(80)-Met(81), revealing that the MMPs were not functionally interchangeable. These sites were homologous to those cleaved in denatured human MBL. Hence, perturbation of the collagen-like structure of MBL by natural mutations or by denaturation renders MBL susceptible to MMP cleavage. MMPs are likely to contribute to MBL deficiency in individuals with variant alleles and may also be involved in clearance of MBL and modulation of the host response in normal individuals.
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PMID:Mannose-binding lectin (MBL) mutants are susceptible to matrix metalloproteinase proteolysis: potential role in human MBL deficiency. 1189 Dec 30


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