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)

Mast cell tryptase purified from human adult skin (AS), adult lung (AL) and newborn foreskin (NS) with a monoclonal antitryptase B2 immunoaffinity Sepharose column was further fractionated by HPLC using a Mono-S cation exchange column at pH 6.5. Tryptases exhibited two clearly separated major fractions, both of which also revealed at least two overlapping peaks. Native tryptase molecules from skin consisted of two diffuse protein bands in SDS-PAGE at about 31 and 35 kDa, whereas those from lung usually exhibited a predominant diffuse band at about 29 kDa. The forms of tryptases separated by Mono-S HPLC gave a different banding pattern in SDS-PAGE. Tryptase from NS exhibited chromatographic peaks that each showed Mr values approximately 1-3 kDa higher than those of tryptase from AS. By gel filtration, the Mr values for native major fractions of tryptases derived from AS and AL were 178 kDa and 141 kDa, respectively. After carbohydrate removal by glycanase, the observed differences in Mr values in SDS-PAGE reduced to two similar sharp bands of Mr approximately 28 kDa and 30 kDa for all tryptase preparations. AS and AL tryptases and their subfractions exhibited similar enzyme kinetic values and similar immunoreactivities in a tryptase immunoassay. Inactivation rates at physiologic ionic strength were similar for both AL and AS tryptases. The results show the enzymatic and antigenic similarity between lung and skin tryptases, and suggest that tryptase is stored mainly as beta-tryptase in human mast cells. Tryptase immunoassay measures similarly both lung and skin tryptases and, thus, this assay is suitable for detection of mast cell activation, in contrast to assays for other proteinases of mast cells, e.g. chymase, cathepsin G and carboxypeptidase, that are present in MC(TC) cells mainly in skin only.
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PMID:Identification and characterization of multiple forms of tryptase from human mast cells. 1019 93

Nerve growth factor-beta (NGF) is known as a growth factor for human basophils and murine mast cells and has recently been shown to also up-regulate mast cell characteristics in human leukaemic mast cells. We have examined here the effect of NGF on the differentiation of normal human mast cells from cord blood progenitors during culture with stem cell factor (SCF), NGF alone or in combination, or fibroblast supernatants. All these supplements induced mast cell immunoreactivity against tryptase, c-Kit and FcepsilonRIalpha, but none of the cells reacted against the basophil specific antibody 2D7 before or during culture. Intracellular tryptase activity increased as well, with maximal levels on combined culture with SCF and NGF. On reverse transcription-polymerase chain reaction (RT-PCR), cells lacked tryptase and chymase and expressed low levels of FcepsilonRI and c-Kit mRNA prior to culture, with marked up-regulation of FcepsilonRI and c-Kit, and with de novo expression of mast-cell specific alpha- and beta-tryptase by week 3, and of chymase by week 5. Only the TrkA and not the p75 NGF receptor was detected at m-RNA and protein level, and only the TrkA NGF receptor was up-regulated during NGF-driven culture. These findings show therefore that, like SCF, NGF is another growth factor that can induce and regulate human mast-cell development and differentiation.
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PMID:Nerve growth factor-beta induces mast-cell marker expression during in vitro culture of human umbilical cord blood cells. 1071 72

Total tryptase levels of 20 ng/mL or higher in a baseline serum sample when the ratio of total to beta-tryptase is 20 or greater strongly suggest underlying systemic mastocytosis. Whether these criteria prove to be more sensitive than a bone marrow biopsy will require further study. Although the absolute level of total tryptase does not predict disease severity, it may provide a practical method for assessing the efficacy of therapeutic interventions designed to reduce the mast cell burden.
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PMID:Serum tryptase and the laboratory diagnosis of systemic mastocytosis. 1090 44

Despite advances in understanding the pathophysiology of asthma, morbidity and mortality in pediatrics continue to rise. Little is known about the initiation and chronicity of inflammation resulting in asthma in this young population. We evaluated 20 "wheezing" children (WC) (median age 14.9 mo) with a minimum of two episodes of wheezing or prolonged wheezing > or = 2 mo in a 6-mo period with bronchoscopy and bronchoalveolar lavage (BAL). Comparisons were made with six normal controls (NC) (median age 23.3 mo) undergoing general anesthesia for elective surgery. BAL fluid cell counts and differentials were determined. The eicosanoids, leukotriene (LT) B(4), LTE(4), prostaglandin (PG)E(2), and 15-hydroxyeicosatetraenoic acid (HETE) and the mast cell mediators, beta-tryptase and PGD(2), were evaluated by enzyme immunoassay (EIA). WC had significant elevations in total BAL cells/ml (p = 0.01), as well as, lymphocytes (LYMPH, p = 0.007), macrophages/monocytes (M&M, p = 0.02), polymorphonuclear cells (PMN, p = 0.02), epithelial cells (EPI, p = 0.03), and eosinophils (EOS, p = 0.04) compared with NC. Levels of PGE(2) (p = 0.0005), 15-HETE (p = 0.002), LTE(4) (p = 0.04), and LTB(4) (p = 0.05) were also increased in WC compared with NC, whereas PGD(2) and beta-tryptase were not. This study confirms that inflammation is present in the airways of very young WC and may differ from patterns seen in adults with asthma.
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PMID:Persistent wheezing in very young children is associated with lower respiratory inflammation. 1137 82

We reported previously that mast cell tryptase is a growth factor for dog tracheal smooth muscle cells. The goals of our current experiments were to determine if tryptase also is mitogenic in cultured human airway smooth muscle cells, to compare its strength as a growth factor with that of other mitogenic serine proteases, and to determine whether its proteolytic actions are required for mitogenesis. Highly purified preparations of human lung beta-tryptase (1-30 nM) caused dose-dependent increases in DNA synthesis in human airway smooth muscle cells. Maximum tryptase-induced increases in DNA synthesis far exceeded those occurring in response to coagulation cascade proteases, such as thrombin, factor Xa, or factor XII, or to other mast cell proteases, such as chymase or mastin. Irreversibly abolishing tryptase's catalytic activity did not alter its effects on increases in DNA synthesis. We conclude that beta-tryptase is a potent mitogenic serine protease in cultured human airway smooth muscle cells. However, its growth stimulatory effects in these cells occur predominantly via nonproteolytic actions.
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PMID:Tryptase's potent mitogenic effects in human airway smooth muscle cells are via nonproteolytic actions. 1179 23

Venous thromboembolism represents a significant cause of morbidity worldwide. The factors that underly thrombophilia are manifold. The concept of Virchow defines the well known triad of stasis, humoral factors, and pathologies of the vascular wall. In the current article, an additional factor, the "accumulation of repair cells" is discussed. This novel concept highlights the mast cell that accumulates around thrombosed vessels and provides a number of important repair molecules including heparin, profibrinolytic tPA, and fibrinogenolytic beta-tryptase. Thus, mast cell recruitment and activation may result in local thrombolysis and prevention of coagulation. In line with this concept, mast cell-deficient mice are more susceptible to lethal thrombogenic stimuli compared to normal mice. The factors (cytokines) that trigger mast cell accumulation and release of repair molecules have also been identified - the most important one appears to be stem cell factor (SCF). All in all. our novel concept suggests that the patho-physiology of thrombosis may involve a "physiologic" cell that provides the same repair molecules that are used for treatment of thrombotic disorders by the physician. Whether an altered availability of components of this cellular repair system can predispose for thrombophilia remains to be determined.
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PMID:New aspects in thrombosis research: possible role of mast cells as profibrinolytic and antithrombotic cells. 1203 77

Tryptase is a serine protease that is stored at low pH in the mast cell secretory granules in complex with heparin proteoglycan. When mast cells are activated, e.g. during allergic responses, the tryptase/heparin complexes are released together with a variety of other preformed inflammatory mediators. Previous crystallization of human beta-tryptase revealed a unique tetrameric structure with all of the active sites facing a central pore that has a limited accessibility both for potential substrates as well as for protease inhibitors. In this study we examined whether human beta-tryptase, in addition, could form active monomers. Incubation of recombinant tetrameric human beta-tryptase at neutral pH and 37 degrees C, followed by gel-filtration analysis using a running buffer containing pig mucosal heparin, led to the formation of enzymically active compounds that were of a size compatible with tryptase monomers in complex with heparin. The monomers were, in contrast to tryptase in the tetrameric form, inhibited by bovine pancreatic trypsin inhibitor. Further, the monomers, but not the tetramers, degraded fibronectin. Formation of active monomers was more pronounced at pH 7.5 than at pH 6.0 and was not detected at room temperature or at high heparin/tryptase ratios. The present findings thus introduce the possibility that human beta-tryptase, after mast cell degranulation and exposure to neutral pH in the tissue, may dissociate into active monomers with properties that are distinct from the tetrameric counterpart. Possibly, some of the biological activities of human tryptase may be attributable to active tryptase in its monomeric rather than tetrameric form.
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PMID:Formation of active monomers from tetrameric human beta-tryptase. 1238 26

Despite maturation arrest, blast cells in acute myeloid leukemia (AML) are often capable of expressing lineage-restricted (granulomonocytic or myelomastocytic) differentiation antigens. Tryptases are lineage-associated serine proteases primarily expressed in mast cells, and less abundantly in blood basophils. We have recently shown that myeloblasts in a group of patients with AML (approximately 40%) produce significant amounts of tryptase(s). In these patients, serum tryptase levels are elevated (> 15 ng/ml) and reflect the total burden of leukemic cells. In most cases, myeloblasts express alpha-tryptase mRNA in excess over beta-tryptase mRNA, and secrete the respective protein (= pro-alpha-tryptase) in a constitutive manner. It was also found that these AML blasts frequentlyco-express tryptase with additional mast cell lineage- and/or basophil-related differentiation antigens including KIT (CD117), histamine, and 2D7. We hypothesize that tryptase-positive AMLs arise from a leukemic progenitor that exhibits a limited potential to differentiate into mast cells and/or basophils.
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PMID:Tryptase a novel biochemical marker of acute myeloid leukemia. 1261 10

Tryptase (alpha and beta) levels in serum are used to assess mast cell involvement in human disease. Using cultured cells, the current study examines the hypothesis that protryptase(s) are spontaneously secreted by mast cells at rest, whereas mature tryptase(s) are stored in secretory granules until their release by activated cells. HMC-1 cells have only beta-tryptase genes and the corresponding mRNA. Mono-Mac-6 cells have both alpha- and beta-tryptase genes but preferentially express alpha-tryptase. Mono-Mac-6 cells spontaneously secrete most of their tryptase, which consists of alpha-protryptase, whereas mature tryptase is retained inside these cells. HMC-1 cells also spontaneously secrete most of their tryptase, identified as beta-protryptase, and retain mature tryptase. Skin-derived mast cells retain most of their tryptase, which is mature, and spontaneously secrete protryptase(s). Total tryptase levels in plasma are detectable but no different in healthy subjects with and without the gene for alpha-tryptase, consistent with pro forms of both alpha- and beta-tryptase being spontaneously secreted. Thus, protryptase(s) are spontaneously secreted by resting mast cells, whereas mature tryptase is retained by mast cells until they are activated to degranulate.
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PMID:Tryptase precursors are preferentially and spontaneously released, whereas mature tryptase is retained by HMC-1 cells, Mono-Mac-6 cells, and human skin-derived mast cells. 1275 48

Remodeling of extracellular matrix is an important component in a variety of inflammatory disorders as well as in normal physiological processes such as wound healing and angiogenesis. Previous investigations have identified the various matrix metalloproteases, e.g., gelatinases A and B, as key players in the degradation of extracellular matrix under such conditions. Here we show that an additional enzyme, human mast cell beta-tryptase, has potent gelatin-degrading properties, indicating a potential contribution of this protease to matrix degradation. Human beta-tryptase was shown to degrade gelatin both in solution and during gelatin zymographic analysis. Further, beta-tryptase was shown to degrade partially denatured collagen type I. beta-Tryptase bound strongly to gelatin, forming high molecular weight complexes that were stable during SDS-PAGE. Mast cells store large amounts of preformed, active tryptase in their secretory granules. Considering the location of mast cells in connective tissues and the recently recognized role of mast cells in disorders in which connective tissue degradation is a key event, e.g., rheumatoid arthritis, it is thus likely that tryptase may contribute to extracellular matrix-degrading processes in vivo.
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PMID:Human mast cell beta-tryptase is a gelatinase. 1287 42


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