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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Complexes of human trypsin and human granulocyte elastase with alpha1-anti-trypsin and alpha2-macroglobulin were isolated and injected intravenously into human volunteers. 2. The elimination of alpha2-macroglobulin complexes with trypsin and elastase followed single-exponential functions with half-lives of 9 and 12 min respectively. The complexes showed no tendency to dissociate. 3. Complexes of alpha1-anti-trypsin with trypsin persisted in the circulation much longer, with a half-life of 3-5 h; complexes of alpha1-anti-trypsin with elastase had an intermediate half-life of 1 h. 4. Dissociation was observed of alpha1-anti-trypsin complexes with transfer of trypsin and elastase to alpha2-macroglobulin. 5. Dialysable radioactivity appeared in the urine soon after the injection of alpha2-macroglobulin complexes, which suggested a breakdown of complexes by cells in the reticuloendothelial system. Radioactivity over the liver achieved maximum values within 30-40 min after the injection of alpha2-macroglobulin complexes but not until 50-70 min after the injection of alpha1-anti-trypsin comlexes. 6. These results support the concept of a key position for alpha2-macroglobulin in the protective mechanisms against endogenous proteases.
Clin Sci Mol Med 1976 Jul
PMID:The disappearance of enzyme-inhibitor complexes from the circulation of man. 5 54

Protease injury of the bronchial epithelium may play an important role in the pathogenesis of many airway diseases including asthma and chronic bronchitis. We hypothesized that neutrophil elastase can cause significant injury to the bronchial epithelium leading to detachment of bronchial epithelial cells. This detachment might be prevented if elastase is released into the airway lumen and the bronchial epithelium forms a barrier preventing access to the basal attachment sites. To assess this, the detachment of bronchial epithelial cells by elastase from extracellular matrix was measured. An increase in the resistance to detachment with time in culture was observed. The resistance to detachment was confirmed in bronchial epithelial cells, which were grown to electrically resistant monolayers on millipore filters and exposed to trypsin and elastase applied to both the apical and basal surfaces. Significantly greater detachment occurred when the proteases were applied at the basal surface versus the apical surface. Injury to the bronchial epithelium may enhance the proteolytic effect on the epithelium by disrupting epithelial barrier function. This was tested by exposing bronchial epithelial cell cultures to cigarette smoke extract before exposure to trypsin and elastase. The detachment of the bronchial epithelial cells exposed on the apical surface was increased greatly after smoke exposure. These data suggest that an intact bronchial epithelium can act as a barrier against proteolytic injury. Such a mechanism might protect the airway epithelium during intraluminal inflammation, and, if defective, might potentiate cigarette smoke-induced airway injury.
Am J Respir Cell Mol Biol 1992 Apr
PMID:Observations of development of resistance to detachment of cultured bovine bronchial epithelial cells in response to protease treatment. 155 Jun 86

The present study examined the effects of elastase, in concentrations present in respiratory secretions, on airway smooth muscle contractile responses in vitro and the magnitude of the airway epithelial inhibition of smooth muscle tension. Experiments were performed on 126 full-thickness tracheal strips from 25 rabbits. Isometric tension responses to acetylcholine (10(-8) to 10(-4) M) and potassium chloride (10 to 110 mM) were examined before and after a 5-min exposure to either porcine pancreatic elastase (PPE) or human neutrophil elastase (HNE). PPE (5 to 40 micrograms/100 microliters) reduced the tension response to acetylcholine but had no effect on the tension response to potassium chloride. PPE and HNE (20 micrograms/100 microliters) produced similar effects. Mechanical removal of the epithelium per se significantly (P less than 0.005) decreased the ED50 response to acetylcholine but did not affect maximal tension. However, the airway epithelial inhibitory effect on the acetylcholine tension response was similar in the presence and absence of PPE (20 micrograms/100 microliters). These data suggest that the diminution of tracheal smooth muscle tension responses to receptor-mediated agonists induced by elastase is a direct effect on the muscle and is not mediated by an effect of elastase on the respiratory epithelium.
Am J Respir Cell Mol Biol 1992 May
PMID:Rabbit trachealis tension responses to receptor-mediated agonists are diminished by elastase. 158 Oct 73

The aim of this work was to study the ability of human alveolar macrophages (AM) of 10 healthy smokers to inactivate alpha 1-proteinase inhibitor (alpha 1PI). Purified alpha 1PI was incubated for 45 min, with human alveolar macrophages before and after stimulation by phorbol myristate acetate (PMA) or opsonized zymosan. As a positive control, the same experiments were performed in parallel with blood human neutrophils (PMN). Results are expressed as percentage of inactivation of alpha 1PI as evaluated from its inhibitory activity against porcine pancreatic elastase. A strong correlation (r = 0.99) was shown when inhibitory activity of alpha 1PI was evaluated against porcine pancreatic elastase or human neutrophil elastase. Unstimulated AM (1.57 +/- 0.9%) as well as stimulated AM (PMA: 1 +/- 0.4%; zymosan: 3 +/- 0.6%) were unable to inactivate alpha 1PI. Gel electrophoresis of alpha 1PI demonstrated that AM before or after stimulation induced a slight proteolysis of alpha 1PI, whereas both cleaved and complexed alpha 1PI were found when alpha 1PI was incubated with activated PMN. Both unstimulated (22 +/- 2.6%) and activated PMN (PMA: 91.7 +/- 4.7%; zymosan: 90 +/- 5.5%) were responsible for a significant inactivation of alpha 1PI. Catalase, in contrast to superoxide dismutase, was responsible for a near complete protection of alpha 1PI inactivation by PMN. To better determine the role of PMN secretory products, especially myeloperoxidase (MPO), we also investigated the effect of zymosan-activated PMN supernatants or of purified MPO on the alpha 1PI-AM reaction. MPO assay in PMN supernatants demonstrated that activated neutrophils released significant amounts of MPO (16.8 +/- 4.1 U/ml), whereas MPO was undetectable in activated AM supernatants.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1991 Nov
PMID:Oxidative inactivation of alpha 1-proteinase inhibitor by alveolar macrophages from healthy smokers requires the presence of myeloperoxidase. 165 63

Arthritis was induced by injecting cationic amidated bovine serum albumin (aBSA) (pI approximately 9.2) into the knee joint of immunized guinea pigs and the mechanisms of articular cartilage destruction were studied morphologically and biochemically. Marked synovitis associated with polymorphonuclear leukocyte (PML) infiltration occurred within 1 day of the challenge. Articular cartilage infiltrated by PMLs was almost completely destroyed after 2 weeks. During the initial destructive process, proteoglycans were depleted from the cartilage and later collagen fibers disappeared. Granulation tissue growing in the inflamed synovium and bone marrow replaced the destroyed cartilage and joint cavity and formed fibrous scar tissue (fibrous ankylosis) by 8 weeks. Subsequently, the knee joints developed cartilagenous ankylosis by 12 weeks and finally bony ankylosis at 28 weeks. Autoradiography using 125I-aBSA and immunofluorescence studies for immunoglobulin (IgG) and complement (C3) demonstrated that the antigen is trapped in all zones of the articular cartilage and serves as a trigger for immune complex formation. Significantly increased neutral proteinase activities against substrates of proteoglycan subunits, [3H]carboxymethylated transferrin and L-pyroglutamyl-L-prolyl-L-valine-paranitroanilide were detected in homogenates of the synovium and cartilage from arthritic knee joints 1 and 2 weeks after induction. Inhibitor studies and pH curves suggested that the proteinase is leukocyte elastase. Measurable amounts of gelatinolytic activity, detected by activation with 4-aminophenylmercuric acetate and inhibited with EDTA, were also present in the same samples, but there was no detectable collagenase activity. The data on SDS-gelatin substrate gel showed that the proteinase is gelatinase derived from PMLs. These results suggest that in aBSA-induced arthritis, elastase and gelatinase from PMLs invading articular cartilage may play important roles in cartilage destruction.
Virchows Arch B Cell Pathol Incl Mol Pathol 1991
PMID:Arthritis induced immunologically with cationic amidated bovine serum albumin in the guinea pig. A morphological and biochemical study on the destruction of articular cartilage. 167 78

To determine whether human neutrophil cathepsin G can act by itself or in concert with human neutrophil elastase to destroy elastic fibers in vivo, we used cryostat sections of human skin as an ex vivo substrate for these leukoproteinases. Specifically stained dermal elastic fibers were quantitated using an accurate and almost entirely automatic morphometric procedure that included computerized threshold selection and elimination of non-elastic dark elements. AA, the area fraction occupied by the dermal elastic fibers, was found to be 0.100 +/- 0.014 (mean +/- SD) for 21 control skin sections originating from a single donor. Measurement of the fiber diameters in these control sections (2.4 +/- 0.8 microns [mean +/- SD]) allowed calculation of the Weibel factor used to convert AA into Vv, the volume fraction occupied by the elastic fibers: Vv was 0.028 +/- 0.004 (mean +/- SD). Incubation of skin sections with elastase, cathepsin G, or mixtures of the two enzymes resulted in an important decrease in AA accompanied by a slight increase in the average fiber diameter. The largest increase (14%) was noticed for cathepsin G and was due to a preferential attack of thin fibers and to fiber fragmentation. The AA of fibers remaining after elastolytic activity of cathepsin G was 20 to 30% that of elastase in this ex vivo assay. On the other hand, cathepsin G stimulated the elastolytic activity of elastase. For instance, the activity of a mixture of 1.1 microM elastase and 1.5 microM cathepsin G was 1.9-fold higher than the sum of the activities of the individual proteinases. The stimulation increased with the cathepsin G concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1991 Jun
PMID:The elastolytic activity of cathepsin G: an ex vivo study with dermal elastin. 171 51

It has been suggested that proteinase enzymes could play an important role in the pathogenesis of chronic bronchial infections including bronchiectasis and cystic fibrosis (CF). Because Pseudomonas aeruginosa frequently colonizes the respiratory tract in bronchiectasis and CF, we examined the in vitro effects of human neutrophil elastase (HNE) and proteinase enzymes produced by P. aeruginosa (elastase: PE; alkaline proteinase: PAP) on the ciliary beat frequency (CBF) and ultrastructure of human nasal ciliated respiratory epithelium. HNE (500 micrograms/ml) progressively reduced CBF and caused marked epithelial disruption; lower concentrations (100 and 20 micrograms/ml) also caused epithelial disruption but without slowing CBF. The effects of HNE (500 micrograms/ml) were completely abolished by adding alpha 1-antitrypsin (5 mg/ml). There was no synergy between HNE and pyocyanin, a product of P. aeruginosa which slows CBF. PE in phosphate-buffered saline also caused epithelial disruption without slowing CBF; however, PE in medium containing divalent metal ions caused CBF slowing as well as epithelial disruption at 100 micrograms/ml. PAP (500 micrograms/ml) had almost no effect on ciliated epithelium. The effects of HNE and PE on nasal and bronchial epithelium obtained from the same patient were similar. Light and transmission electron microscopy revealed that HNE and PE were cytotoxic and caused detachment of epithelial cells from neighboring cells and the basement membrane. There was cytoplasmic blebbing of the cell surface and mitochondrial damage; however, no increase of abnormalities in the ultrastructure of cilia on living cells was seen. These results support the hypothesis that HNE and PE contribute to the delayed mucociliary clearance and epithelial damage that is observed in patients with chronic bronchial infection.
Am J Respir Cell Mol Biol 1991 Jan
PMID:Effects of human neutrophil elastase and Pseudomonas aeruginosa proteinases on human respiratory epithelium. 189 52

The Mmineral springs alpha 1-antitrypsin (alpha 1AT) allele, causing alpha 1AT deficiency and emphysema, is unique among the alpha 1AT-deficiency alleles in that it was observed in a black family, whereas most mutations causing alpha 1AT deficiency are confined to Caucasian populations of European descent. Immobilized pH gradient analysis of serum demonstrated that alpha 1AT Mmineral springs migrated cathodal to the normal M2 allele. Evaluation of Mmineral springs alpha 1AT as an inhibitor of neutrophil elastase, its natural substrate, demonstrated markedly lower than normal function. Characterization of the alpha 1AT Mmineral springs gene demonstrated that it differed from the common normal M1(Ala213) allele by a single-base substitution causing the amino acid substitution Gly-67 (GGG)----Glu-67 (GAG). Capitalizing on the fact that this mutation creates a polymorphism for the restriction endonuclease AvaII, family analysis demonstrated that the Mmineral springs alpha 1AT allele was transmitted in an autosomal-codominant fashion. Evaluation of genomic DNA showed that the index case was homozygous for the alpha 1AT Mmineral springs allele. Cytoplasmic blot analysis of blood monocytes of the Mmineral springs homozygote demonstrated levels of alpha 1AT mRNA transcripts comparable to those in cells of a normal M1 (Val213) homozygote control. Evaluation of in vitro translation of Mmineral springs alpha 1AT mRNA transcripts demonstrated a normal capacity to direct the translation of alpha 1AT. Evaluation of secretion of alpha 1AT by the blood monocytes by pulse-chase labeling with [35S]methionine, however, demonstrated less secretion by the Mmineral springs cells than normal cells. To characterize the posttranslational events causing the alpha 1AT-secretory defect associated with the alpha 1AT Mmineral springs gene, retroviral gene transfer was used to establish polyclonal populations of murine fibroblasts containing either a normal human M1 alpha 1AT cDNA or an Mmineral springs alpha 1AT cDNA and expressing comparable levels of human alpha 1AT mRNA transcripts. Pulse-chase labeling of these cells with [35S]methionine demonstrated less secretion of human alpha 1AT from the Mmineral springs cells than from the M1 cells, and evaluation of cell lysates also demonstrated lower amounts of intracellular human alpha 1AT in the Mmineral springs cells than in the normal M1 control cells. Thus, the Gly-67 --> Glu mutation that characterizes Mmineral springs causes reduced alpha 1AT secretion on the basis of aberrant posttranslational alpha 1AT biosynthesis by a mechanism distinct from that associated with the alpha 1AT Z allele, whereby intracellular aggregation of the mutant protein is etiologic of the alpha 1AT-secretory defect. Furthermore, for the alpha 1AT protein that does reach the circulation, this mutation markedly affects the ability of the molecule to inhibit neutrophil elastase; i.e., the alpha 1AT Mmineral springs allele predisposes to emphysema on the basis of serum apha 1AT deficiency coupled with alpha AT dysfunction.
Mol Cell Biol 1990 Jan
PMID:Molecular basis of alpha 1-antitrypsin deficiency and emphysema associated with the alpha 1-antitrypsin Mmineral springs allele. 196 87

Alterations in proteoglycans (PG) located in the pulmonary interstitium may influence extracellular matrix (ECM) structure and assembly during the development of diseases in which increased numbers of neutrophils enter the lung. To evaluate potential mechanisms of PG degradation, neutrophils or purified neutrophil products were incubated with ECM that had been produced by cultured neonatal rat vascular smooth muscle cells (SMC) or lung fibroblasts (LF) and metabolically labeled with 35SO4. Matrix PG solubilization was expressed as a percentage of the spontaneous [35SO4]PG solubilization that occurred in the presence of buffer alone. Solubilization by unstimulated neutrophils was 105.8 +/- 3.1% (mean +/- SEM, n = 6) and 101.7 +/- 3.05 (n = 8) using ECM that had been produced by LF and SMC, respectively. Solubilization by neutrophils that had been stimulated with formyl-methionine-leucine-phenylalanine (FMLP) in the presence of cytochalasin B (CB) was 189.7 +/- 5.8% and 298.2 +/- 26.2% using ECM produced by LF and SMC, respectively. Matrix that had been produced by SMC was used to evaluate which neutrophil products were responsible for the degradation of PG. Addition of a specific inhibitor of neutrophil elastase (NE) to stimulated polymorphonuclear leukocytes (PMN) reduced PG solubilization by 88.3 +/- 4.8% (n = 8). Addition of an inhibitor of cathepsin G (CG), as well, did not further reduce PG degradation. Purified CG and myeloperoxidase solubilized significantly more PG, 125.8 +/- 6.2% (n = 9) and 143.2 +/- 8.1% (n = 6), respectively (P less than 0.01), than was solubilized spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1990 Mar
PMID:Mechanisms of extracellular matrix proteoglycan degradation by human neutrophils. 215 32

Factors that modulate neutrophil migration into the lung are poorly understood. However, there is evidence that neutrophil activation by formylmethionylleucylphenylalanine (FMLP) depends upon a surface proteinase with chymotrypsin-like activity. This suggests that chymotrypsin inhibitors such as alpha-1-proteinase inhibitor (alpha 1PI) could modify neutrophil migration in response to FMLP. We have studied neutrophil chemotaxis using the multiple blind well assay system. This article presents evidence that alpha 1PI is an inhibitor of neutrophil migration in response to FMLP. The effect is related to the inhibitory function of the protein. Alpha-1-antichymotrypsin is more potent than alpha 1PI as an inhibitor of this movement, whereas antileukoprotease is less potent. The results suggest that a cell membrane-bound serine proteinase (perhaps cathepsin G) is necessary for the enhancement of cell movement after receptor binding of FMLP. Oxidized alpha 1PI or a 4,000-D peptide cleaved from alpha 1PI by porcine pancreatic elastase or human neutrophil elastase are capable of enhancing cell motility. The results suggest that alpha 1PI may play a role in cell migration into the lung during acute inflammatory process.
Am J Respir Cell Mol Biol 1990 Feb
PMID:Effect of alpha-1-proteinase inhibitor on neutrophil chemotaxis. 230 72


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