Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

From the supernatant of B. melaninogenicus ss. asaccharolyticus culture, a protein fraction was isolated by ethanol precipitation. The fraction was tested for the presence of clotting and fibrinolytic activities by application of quantitative techniques and specific substrates for measurement of prothrombin and plasminogen activation, and collagenase and elastase activity. It is postulated that ability of Bacteroides melaninogenicus ss. asaccharolyticus extracellular factors to clot fibrinogen and activate plasminogen, are due to a limited proteolysis by the proteolytic enzymes produced by this microorganism and not to the existence of specific B. melaninogenicus coagulase of plasminogen activator.
 ...
PMID:The nature of clotting and fibrinolytic activities of Bacteroids melaninogenicus. 2 65

To elucidate the mechanism of synovial damage in rheumatoid arthritis, we studied the activation of latent collagenases released from adherent rheumatoid synovial cells in culture. Latent enzyme was not complexed with alpha2 macroglobulin, the prinicpal proteinase inhibitor in serum, and could be activated by trypsin in the presence of alpha2 macroglobulin if sufficient proteinase was added to saturate inhibitor. Latent collagenase bound half as effectively to collagen fibrils as active enzyme. Plasmin was a threefold better activator of latent enzyme than trypsin and could be generated by addition of plasminogen to synovial-cell cultures. Production of both collagenase and plasminogen activator was inhibited by dexamethasone (10(-9) M). These studies emphasize in importance of control of activation in regulation collagenase activity, It is likely that rheumatoid synovium produces both latent collagenase and plasminogen activator; plasmin is activated from its zymogen, plasminogen, present in inflamed tissues, and in turn activates collagenase.
 ...
PMID:Endogenous activation of latent collagenase by rheumatoid synovial cells. Evidence for a role of plasminogen activator. 6 27

Thioglycolate-stimulated mouse peritoneal macrophages secrete a Proteinase which degrades insoluble elastin. There is little elastase activity in cell lysates but the bulk of the enzyme accumulates extracellularly during culture in serum-free medium. The secretion of elastase is sustained for over 12 days in culture and continued secretion of elastase requires protein synthesis. Unstimulated macrophages secrete very little elastase activity but can be triggered to secrete higher levels of this enzyme by phagocytosis and intracellular storage of latex particles. The macrophages elastase is a distinctive proteinase differing from the elastases of pancreas and granulocytes and is distinct from the other secreted proteinases of macrophages, namely, collagenase and plasminogen activator. The macrophages elastase is a serine proteinase and is inhibited by di-isopropyl phosphoro-fluoridate, ovoinhibitor, EDTA, dithiothretiol, and serum. Its activity is little affected by soybean trypsin inhibitor, turkey ovomucoid and chloromethyl ketones derived from tosyl lysine, tosyl phenylalanine, and acetyltetra alanine. Hydrolysis by macrophage elastase of chromogenic ester substrates for pancreatic elastase could not be detected. Elastase secretion by stimulated macrophages exceeds that by primary and established fibroblast cell strains. It is likely that elastase secretion by macrophages plays a major role in the pathogenesis of chronic destructive pulmonary diseases such as emphysema.
 ...
PMID:Elastase secretion by stimulated macrophages. Characterization and regulation. 16 96

We have observed that treatment of rabbit synovial fibroblasts with proteolytic enzymes can induce secretion of collagenase (EC 3.4.24.7) and plasminogen activator (EC 3.4.21.-). Cells treated for 2-24 hr with plasmin, trypsin, chymotrypsin, pancreatic elastase, papain, bromelain, thermolysin, or alpha-protease but not with thrombin or neuraminidase secreted detectable amounts of collagenase within 16-48 hr. Treatment of fibroblasts with trypsin also induced secretion of plasminogen activator. Proteases initiated secretion of collagenase (up to 20 units per 10(6) cells per 24 hr) only when treatment produced decreased cell adhesion. Collagenase production did not depend on continued presence of proteolytic activity or on subsequent cell adhesion, spreading, or proliferation. Routine subculturing with crude trypsin also induced collagenase secretion by cells. Secretion of collagenase was prevented and normal spreading was obtained if the trypsinized cells were placed into medium containing fetal calf serum. Soybean trypsin inhibitor, alpha(1)-antitrypsin, bovine serum albumin, collagen, and fibronectin did not inhibit collagenase production. Although proteases that induced collagenase secretion also removed surface glycoprotein, the kinetics of induction of cell protease secretion were different from those for removal of fibronectin. Physiological inducers of secretion of collagenase and plasminogen activator by cells have not been identified. These results suggest that extracellular proteases in conjunction with plasma proteins may govern protease secretion by cells.
 ...
PMID:Proteases induce secretion of collagenase and plasminogen activator by fibroblasts. 20 72

A continuous line of mouse macrophages (P388D1) has been shown to secrete elastase, collagenase, and plasminogen activator at activities comparable to those of macrophages elicited by an inflammatory stimulus in vivo. At physiologic concentrations anti-inflammatory glucocorticoids selectively and reversibly inhibited secretion of the three proteinases but did not inhibit secretion of lysozyme, a constitutive enzyme produced by the P388D1 cells. The secretion of the neutral proteinases was inhibited 50% by 2 to 10 nM dexamethasone. Proliferation of the macrophages was also glucocorticoid sensitive. The P388D1 macrophages contained about 4000 saturable glucocorticoid-binding sites per cell. Concentrations of hormone saturating the high affinity receptor site (for dexamethasone the dissociation constant for steroid-receptor binding, Kd, was 4 nM) correlated well with concentrations inhibiting secretion of the proteinases. Only glucocorticoids and progesterone competed for binding to the specific receptors. Temperature-sensitive translocation of hormone-receptor complexes from "cytoplasm" to nucleus similar to that found with rat thymocytes was demonstrated. Thus, the interaction between glucocorticoids and the P388D1 cell line provides a model for the regulation of macrophage secretion of neutral proteinases under normal and stress conditions.
 ...
PMID:Glucocorticoid receptors and glucocorticoid-sensitive secretion of neutral proteinases in a macrophage line. 20 6

The effects of glucocorticoids on biochemical functions of macrophages from man, mouse, rabbit, and guinea pig were examined. Secretion of plasminogen activator by human peripheral blood monocytes was decreased by 50% with 1 nM dexamethasone. Differentiation of murine monocytic and granulocytic colonies in agar from bone marrow precursors was decreased by 50% at 7 days with 20 nM dexamethasone. Secretion of elastase, collagenase, and plasminogen activator by resident and thioglycollate-elicited mouse peritoneal macrophages was decreased by dexamethasone, cortisol, and triamcinolone acetonide (1--1,000 nM), but not by progesterone, estradiol, and dihydrotestosterone (1,000 nM); in contrast, secretion of lysozyme was not affected by glucocorticoids or other steroids. The inhibition of macrophage secretion by dexamethasone was both time and dose dependent. Effects were detected within 1--6 h after addition of the glucocorticoids, became maximum by 24 h, and were reversed during a similar time period after removal of the hormones. The extent of inhibition of macrophage secretion increased with increasing glucocorticoid concentration. Half-maximum inhibition of secretion of elastase, collagenase, and plasminogen activator was seen at dexamethasone concentrations (1--10 nM) similar to those that half-saturated the specific glucocorticoid receptors in these cells. At high concentrations of dexamethasone (100--1,000 nM) the secretion of plasminogen activator was inhibited to a greater extent (greater than 95%) than the secretion of elastase (60--80%). Progesterone alone had no effect on secretion, but it blocked the inhibitory effects of dexamethasone and cortisol. Secretion of collagenase, neutral proteinases, and plasminogen activator by elicited rabbit alveolar macrophages was inhibited with glucocorticoids (0.1--100 nM) but not with progesterone or sex steroids. Secretion of a neutral elastinolytic proteinase by guinea pig alveolar macrophages was also inhibited by dexamethasone. These data support the regulatory role of glucocorticoids on macrophage functions at physiological concentrations.
 ...
PMID:Biochemical actions of glucocorticoids on macrophages in culture. Specific inhibition of elastase, collagenase, and plasminogen activator secretion and effects on other metabolic functions. 21 Feb 48

Macrophages in culture secrete a variety of products including neutral protease activities such as plasminogen activator(s) (P.A.), collagenase and elastase. These products are not made by unstimulated macrophages, but only after induction by inflammatory stimuli, phagocytosis and lymphokines. Phagocytosis induces the prompt release of high levels of P.A. by endotoxin-primed macrophages and prolonged secretion follows uptake of non-degradable particles. Stimulation of lymphocytes results in the release of a supernatant product which enhances P.A. secretion by unstimulated mouse macrophages up to 5-fold. The production of the P.A. inducer (P.A.I.) is immunologically specific and is found in allogeneic mixed leukocyte culture (MLC) reactions, but not in syngeneic controls. The P.A. is also induced in activated macrophages from animals infected with BCG of T. cruzi and challenged with specific antigen. Production of the P.A.I. in MLC reactions depends on the presence of thymus-derived (T) lymphocytes and is closely correlated with the appearance of macrophage migration inhibition factor (MIF). The induction of macrophage P.A. and other proteases provides an important pathway for activating macrophages in delayed hypersensitivity reactions and could contribute significantly to tissue destruction in chronic inflammatory diseases in joints.
 ...
PMID:Macrophage proteases and rheumatic diseases: regulation of plasminogen activator by thymus-derived lymphocytes. 34 80

Neutrophils and macrophages produce, store and release large amounts of various acid and neutral proteinases. The two main proteinases of neutrophils are elastase and cathepsin G. They are localized in the azurophil granules, together with proteinase 3 and the acid cathepsins B and D. In addition neutrophils contain collagenase in the specific granules, acid proteinases in the C-particles and plasminogen activator in organelles with the characteristics of secretory vesicles. The granule-bound proteinases are released during phagocytosis while plasminogen activator is apparently secreted. In macrophages, the acid hydrolases are bound to lysosomes while the neutral proteinases are confined to secretory vesicles. The main mechanism of enzyme release in macrophages is secretion. Lysosomal hydrolases are also released by phagocytosis. Enzyme secretion is a characteristic property of activated or inflammatory macrophages. Macrophages become activated after phagocytosis of certain particles and the metabolic burst appears to be an initial event in the activation process. The action of neutrophils and of purified elastase or plasmin on cartilage was tested. These experiments indicate that neutrophil-mediated degradation of cartilage proteoglycans is largely dependent on elastase.
 ...
PMID:Cellular mechanisms of proteinase release from inflammatory cells and the degradation of extracellular proteins. 39 84

A possible mechanism for tumor cell invasion of normal tissue might be secretion of proteolytic enzymes. This study compares and contrasts production and secretion of proteinases by cell cultures of normal and chemically transformed mouse epithelial cells. Lysates of normal and neoplastic cells contain similar amounts of neutral proteinase, cathepsin D and plasminogen activator. Neither collagenase nor elastase could be identified in lysates of, or serum-free culture medium bathing, normal or neoplastic cells. Neoplastic cells secrete ten times more plasminogen activator than normal cells. Our data support the hypothesis that plasminogen activator produced by neoplastic cells could fuction to activate latent proteolytic enzymes secreted by connective tissue cells which might result in spread of neoplastic cells into normal tissue.
 ...
PMID:Production and secretion of proteolytic enzymes by normal and neoplastic cells. 45 22

Heparin is a potent inhibitor of arterial smooth muscle cell (SMC) migration and proliferation in vivo and in vitro. We propose that heparin affects these SMC functions by interfering with either the expression or the activity of secreted proteases required for cell movement. We have reported that heparin selectively inhibits the expression of tissue-type plasminogen activator in SMCs during mitogenesis. In this study we show that the gene expression of another kind of protease, interstitial collagenase, is induced by fetal bovine serum and is also suppressed by heparin. The inhibitory effect on the induced collagenase mRNA is specific to heparin-like molecules and does not depend on the anticoagulant activity of heparin. The induction of the collagenase gene depends on the protein kinase C pathway, since it can be induced by phorbol esters such as phorbol 12-myristate 13-acetate and blocked by inhibitors such as H-7 and staurosporine. In transient transfection assays with chloramphenicol acetyltransferase constructs containing the phorbol ester-responsive element introduced into baboon SMCs, heparin inhibits transcription induced by serum or phorbol 12-myristate 13-acetate. These results support the conclusion that, in primate SMCs, interstitial collagenase gene transcription mediated by the phorbol ester-responsive element is blocked by heparin.
 ...
PMID:Heparin inhibits collagenase gene expression mediated by phorbol ester-responsive element in primate arterial smooth muscle cells. 131 15


1 2 3 4 5 6 7 8 9 10 Next >>