Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We tested four synthetic substances for their histochemical value to demonstrate the catalytic activities of chymase or tryptase in mast cells in sections of human gut. Both Suc-Ala-Ala-Phe-4 methoxy-2-naphthylamide (MNA) and N-acetyl-L-methionine-alpha-naphthyl ester (alpha-N-O-Met) reacted with chymase but not tryptase in mast cells. Conversely, D-Val-Leu-Arg-MNA and Z-Ala-Ala-Lys-MNA were hydrolyzed by mast cell tryptase but not chymase. These results were confirmed by use of two inhibitors of chymotrypsin-like activity, chymostatin and Z-Gly-Leu-Phe-chloromethyl ketone (CK) and two inhibitors of trypsin-like activity, Tos-Lys-CK and D-Val-Leu-Arg-CK. Excellent staining reactions were obtained on cryostat sections of unfixed or aldehyde-fixed tissues and on paraffin sections of Carnoy-fixed tissues. For chymase, however, Suc-Ala-Ala-Phe-MNA is preferred on cryostat sections because it is more specific. On paraffin sections alpha-N-O-Met is preferred because other cells are not then stained. For tryptase, Z-Ala-Ala-Lys-MNA was more selective and more specific and is the preferred general purpose substrate on cryostat sections of aldehyde-fixed tissues and for paraffin sections. D-Val-Leu-Arg-MNA is the preferred substrate for cryostat sections of unfixed tissue. Only a limited number of mast cells showed a reaction for chymase, and these occurred mainly in the submucosa. All mast cells, however, gave a reaction for tryptase, and we recommend the use of either substrate for this enzyme for routine detection of mast cells in human tissues. Double staining for the two main mast cell proteases is most conveniently undertaken on paraffin sections of Carnoy-fixed tissues using MNA substrates for tryptase and alpha-N-O-Met for chymase.
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PMID:Enzyme histochemical discrimination between tryptase and chymase in mast cells of human gut. 264 38

The mast cell proteases tryptase and chymase have long been known to constitute one-fifth of the total protein in mast cells. However, their biological functions have not been easy to study because of the difficulty in obtaining sufficient amounts of the enzymes to study their biological functions. Recently, we have been fortunate to have available a permanent line of dog mastocytoma cells to purify both enzymes to homogeneity, and we have used the purified enzymes in two ways. First, in a series of biological studies, we have discovered unique and potent actions of the enzymes that may provide important insights into the pathogenesis of diseases such as asthma and cystic fibrosis. Important biological activities are also likely to exist in other tissues. Because of their structures, mast cell proteases are likely to act in proximity to their sites of release. Thus, the presence and amounts of tryptase and chymase in specific loci may play important roles in tissue responses. In diseases such as asthma and cystic fibrosis, there is evidence that the expression of these mast cell enzymes changes, and these changes have important pathogenetic implications. Second, we have begun to perform structural studies of the enzymes. The recent cloning of tryptase by our group should assist in the better understanding of its functions. Crystallography of the pure proteins should provide further insights and could be the basis of rational development of potent and selective drugs that will inhibit their actions.
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PMID:Roles of mast cell proteases in airways. 266 41

Mast cells are abundant and are widely distributed in airway tissues. They release their secretory products into microenvironments as diverse as epithelium, smooth muscle, and glands. The major secretory granule proteins of mast cells are proteases that are released outside of the cell with heparin, histamine, and other preformed mediators. In the past few years, investigations in a number of laboratories have rapidly increased our knowledge of the chemical and biological properties of the two major mast cell secretory proteases, tryptase and chymase. Recent experimental evidence suggests the possibility of biologically important roles for tryptase and chymase in the airways, particularly in the regulation of neuropeptide activity, bronchomotor tone, and submucosal gland secretion. The purpose of this commentary is to examine critically the evidence of participation of these mast cell proteases in molecular and physiological events in the airways.
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PMID:Roles of mast cell tryptase and chymase in airway function. 266 22

Although a great deal has been learned about the mediators produced by mast cells, the ultimate biologic function(s) of mast cell remains a mystery. Histamine, LTC4, PAF, and possibly tryptase (C3a generation) all enhance vasopermeability. Mediators with anticoagulant activities such as heparin and tryptase (fibrinogenolysis) and antithrombotic activity, PGD2, would appear to facilitate dispersion in tissues of the plasma ultrafiltrate brought there by the subgroup of mediators that enhance vasopermeability. In contrast, PAF causes platelet aggregation and chymase may cause arteriolar vasoconstriction (decreasing the volume of plasma reaching venules) by generation of angiotensin II. Assessment of any differential production of mediators by different types of mast cells will be of obvious importance in sorting out the physiologic responses to mast cell activation as well as the pathophysiology of allergic reactions.
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PMID:Mediators of human mast cells and human mast cell subsets. 310 66

Mast cell secretory granules contain unique tryptic and chymotryptic serine proteases that differ between species and tissues. Direct comparison of these proteases in single-cell types has been hindered by the difficulty of obtaining adequate numbers of pure mast cells. In this study, we were able to compare tryptic and chymotryptic enzyme activity in cells of presumed monoclonal origin, using two stable lines ('BR' and 'G') of dog mastocytomas. The gel-filtration profiles, inhibitor susceptibilities and substrate preferences of tryptic and chymotryptic mastocytoma protease activities established their close resemblance to the tryptases and chymases of human and rodent mast cells. Striking heterogeneity was observed in the amounts and solubilities of the tryptic and chymotryptic activity in the two different mastocytoma cell lines. Incubation of cells from both lines with calcium ionophore A23187 caused non-cytotoxic release of protease activity. In contrast to chymase from rat connective tissue mast cells, protease activity that was insoluble after extraction at low ionic strength became soluble following ionophore-stimulated release. Neither tryptic nor chymotryptic activity was activated during degranulation, suggesting the absence of inactive precursors. Cells of the 'BR' line released both tryptic and chymotryptic activity in parallel with the granule marker histamine; cells of the 'G' line released a much smaller proportion of tryptic activity than of either chymotryptic activity or histamine. These differences in release of granule constituents from cells of common origin could be explained by developmental variations in the production of performed mediators or by differential regulation of preformed mediator release. We conclude that the differences in protease content, solubility and release in these mastocytoma lines are useful in evaluating the potential pathophysiological significance of the contribution of proteases to mast cell heterogeneity.
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PMID:Tryptase and chymase: comparison of extraction and release in two dog mastocytoma lines. 312 30

Serine class proteinases with trypsin-like and chymotrypsin-like specificity were purified from dog mastocytoma tissue. An antiserum was produced against the chymotrypsin-like proteinase. The antiserum reacted with mast cells in skin sections prepared from normal dogs consistent with the proteinase being a mast cell constituent. The antiserum also cross-reacted with the major chymotrypsin-like proteinase isolated from normal dog skin and partially cross-reacted with human skin chymase. No cross-reaction was detected with rat chymase. The trypsin-like proteinase from dog mastocytoma tissue was similar to tryptase isolated from human skin. It had a similar subunit structure, was not inhibited by many protein proteolytic enzyme inhibitors, bound to heparin, and reacted strongly with antiserum against human tryptase. Antiserum against human tryptase also reacted with mast cells in skin sections prepared from normal dog skin. No immunocytochemical labeling of rat skin mast cells was observed with anti-human tryptase. These studies establish the presence of a trypsin-like and chymotrypsin-like proteinase in dog skin mast cells and provide immunological evidence which suggests that both proteinases are more closely related to human than rat mast cell proteinases. These immunological and biochemical relationships are important when comparing the roles of these proteinases in different animals.
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PMID:Purification and identification of two serine class proteinases from dog mast biochemically and immunologically similar to human proteinases tryptase and chymase. 312 77

Mast cell populations can be distinguished by differences in the content and substrate specificity of their two major cytoplasmic granule proteases, the chymases and the tryptases. To explore the origins of differences in the types of proteases present in mast cells, we used a double cytochemical staining technique to reveal both chymase and tryptase in cells from four lines of dog mast cell tumors containing both enzymes. We expected that if chymase and tryptase were expressed together during cell development the relative staining intensity of chymase compared to tryptase would be constant among different cells of each tumor. Instead, we found substantial variation in the relative intensity of chymase and tryptase staining among cells of a given mastocytoma line, each of which contained cells presumed to be monoclonal in origin but heterogeneous with respect to cell development. The overall staining intensity for chymase or tryptase correlated with the amount of protease activity in extracts of tumor homogenates. Staining specificity was established by use of selective inhibitors and competitive substrates and was tested on various types of dog cells obtained by bronchoalveolar lavage. The results suggest that active chymase and tryptase may be expressed differently during mast cell differentiation and support the possibility of a close developmental relationship between mast cells differing in protease phenotype. Moreover, the success of the staining procedures applied to mastocytoma cells suggests that they may be of general utility in phenotyping of mast cells according to the protease activities present in their granules.
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PMID:Chymase and tryptase in dog mastocytoma cells: asynchronous expression as revealed by enzyme cytochemical staining. 313 86

We have previously shown that a confluent layer of mature mast cells is obtained when lymph node cells are grown on embryonic fibroblast monolayers. Two populations of mast cells may be observed, depending on treatment of the mice from which the lymph node cells are derived. We report now on the morphometric evaluation of these two mast cell entities, and we correlate this with cellular biochemistry and secretory behaviour. The first type of mast cell is small (265 +/- 20 microns 3). It arises from the embryonic monolayer and the cells have feathers resembling those of connective tissue mast cells. These cultured cells are filled with about 1000 homogeneous electron-dense granules, which usually range in diameter from 0.05 to 0.2 microns. The second type of mast cell arises from precursors originating from the lymph node and they have feathers of mucosal mast cells. These cells are larger (480 +/- 40 microns 3) and contain about 300 heterogeneous granules, which range from 0.1 to 0.8 microns. Both cell entities contain about equal amounts of histamine, serotonin and chymase. Biologically, the two cell entities secrete soluble mediators (histamine and serotonin) at different rates compared to the rate at which they secrete chymase. We suggest that such a pattern of secretion exhibits a form of degranulation that permits the release of freely diffusible mediators that are loosely bound to granules, but only partially permits the secretion of insoluble mediators, which are stored in the granules. Alternatively, there might be a mechanism that rapidly inactivates or binds chymase so that only the vasoamines will be free.
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PMID:Two populations of mast cells on fibroblast monolayers: correlation of quantitative microscopy and functional activity. 325 2

The distribution and concentration of human T (tryptase-positive, chymase-negative) and TC (tryptase-positive, chymase-positive) mast cells were examined in Carnoy's-fixed specimens of the gastrointestinal tract of normal individuals, patients with inflammatory bowel diseases, and patients with immunodeficiency disorders. In normal specimens, T mast cells predominated in the mucosa (89%), with a mean concentration of 17,850 +/- 4,998 per mm3 (+/- SD, n = 16), whereas TC mast cells predominated in the submucosa (90%) with a mean concentration of 7,516 +/- 1,227 per mm3 (+/- SD, n = 16). The concentrations of T and TC mast cells in specimens of ileum from five patients with active Crohn's disease and of colon from three patients with active ulcerative colitis were not significantly different (p greater than 0.4) from normal values. Three patients with combined immunodeficiency disorders demonstrated a marked decrease in the concentration of the T mast cells in the intestinal mucosa, to 540 +/- 630, and a corresponding decrease in the percentage of T mast cells to 9%. Concentrations of TC mast cells were unchanged, both in the mucosa and in the submucosa. In three patients with acquired immunodeficiency syndrome, a similar deficiency of the T mast cell type was observed in the ileal mucosa, with a mean concentration of 788 +/- 534 T mast cells per mm3, but not in the appendiceal and colonic mucosa of one of the three patients. These findings indicate a role for functional T lymphocytes in the development of the T mast cell type in humans, and suggest divergent pathways for development of T and TC mast cells.
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PMID:Deficiency of the tryptase-positive, chymase-negative mast cell type in gastrointestinal mucosa of patients with defective T lymphocyte function. 329 46

The secretory granules of rat serosal mast cells are able efficiently to degrade the apolipoprotein B component of low density lipoproteins (LDL) Kokkonen, J. O., and Kovanen, P. T. (1985) J. Biol. Chem. 260, 14756-14763). The granules are known to contain two neutral proteases with complementary specificities: a chymotrypsin-like endopeptidase called chymase, and an exopeptidase, the granule carboxypeptidase A. The role of this enzyme pair in the proteolytic degradation of LDL was studied with the aid of specific enzyme inhibitors. Incubation of LDL with intact granules (both enzymes active) led to the formation of numerous low molecular weight peptides and the liberation of free amino acids, most of which (95%) were aromatic (Phe, Tyr, Trp) or branched-chain aliphatic (Leu, Ile, Val). Selective inhibition of granule carboxypeptidase A (leaving chymase active) blocked the liberation of free amino acids, but left the formation of peptides uninhibited. On the other hand, selective inhibition of granule chymase (leaving carboxypeptidase A active) totally abolished the proteolytic degradation of LDL. The results are consistent with a model according to which the proteolytic degradation of LDL by mast cell granules results from coordinated action of the two granule-bound enzymes, whereby the chymase first cleaves peptides from the apolipoprotein B of LDL, and thereafter the carboxypeptidase A cleaves amino acids from the peptides formed.
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PMID:Low density lipoprotein degradation by secretory granules of rat mast cells. Sequential degradation of apolipoprotein B by granule chymase and carboxypeptidase A. 353 21


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