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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We know that the mast cell or basophil degranulation and the release of chemical mediators such as histamine may play an important role in inducing immediate type allergic reactions. In this experiment, employing purified rat peritoneal mast cells (RPMC) the degranulation pattern of RPMC and percent release of histamine from RPMC by pharmacologic (compound 48/80, kallikrein or peptidoglycan) or allergic (IgE-anti IgE complex) stimuli were examined. The inhibitory effects of catecholamine (isoproterenol), an adenylate cyclase stimulator, methylxanthine (IBMX: 3-isobutyl-1-methyl-xanthine), a phosphodiesterase inhibitor and chemical mediators (histamine, serotonin, bradykinin) on compound 48/80-induced RPMC degranulation and also those of catecholamine, methylxanthine and chemical mediators on IgE-anti IgE complex-induced histamine release from RPMC were tested. Compound 48/80-induced RPMC degranulation was remarkably inhibited not only by treatment with isoproterenol and IBMX, but also by treatment with histamine. It was not, however, inhibited by serotonin or bradykinin. The inhibitory effect of histamine on compound 48/80-induced RPMC degranulation was blocked by pretreatment with H2-antagonist (cimetidine), but not by H1-antagonist (diphenhydramine). The cyclic adenosine 3',5'-monophosphate (cAMP) content of RPMC was significantly increased by pretreatment with histamine as well as isoproterenol and IBMX. These facts suggest that cAMP acts as a regulator or modulator of the RPMC degranulation and the histamine release from mast cells and that the inhibitory effect induced by histamine may be related to the H2-receptor existing on the surface of mast cells.
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PMID:[Studies on the degranulation and histamine release of purified rat peritoneal mast cells. The inhibitory effect of histamine and other chemicals]. 247 72

Effects of condensed tannins isolated from Rhei Rhizoma on the activities of angiotensin converting enzyme (ACE) and various proteases were examined in vitro. Among the various condensed tannins tested, procyanidin B-5 3,3'-di-O-gallate and procyanidin C-1 3,3',3"-tri-O-gallate strongly inhibited the activity of ACE. The concentration of procyanidin B-5 3,3'-di-O-gallate required for 50% inhibition of ACE was 1.3 X 10(-6) M. The inhibition of ACE by condensed tannins was reversible and non-competitive, according to dialysis and to Dixon plots. However, over one hundred times the concentration was required to inhibit activities of other proteases such as trypsin, chymotrypsin, leucine aminopeptidase, carboxypeptidase A and urinary kallikrein. These results suggest that the inhibitory effects of condensed tannins on the activities of ACE are specific.
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PMID:Inhibitory effects of condensed tannins on angiotensin converting enzyme. 303 68

The effect of tryptase, a neutral protease released from human lung mast cell secretory granules, on the tissue prokallikrein present in human urine was examined. Tryptase has been shown previously to lack activity against plasma prokallikrein. Purified tryptase was incubated with a concentrated preparation of urinary prokallikrein. No increase in kallikrein-like enzymatic activity or immunoreactive tissue kallikrein was detected. Activation of urinary prokallikrein with trypsin served as a positive control. Furthermore, preincubation of urinary prokallikrein with tryptase did not diminish the subsequent activation of urinary prokallikrein by trypsin. Therefore, tryptase neither activates nor destroys human tissue or plasma prokallikreins.
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PMID:Tryptase and kinin generation: tryptase from human mast cells does not activate human urinary prokallikrein. 329 74

Mediator release from mast cells is an initial step in the immediate-type hypersensitivity. Thus, the interaction of neutral proteases released from mast cells with plasma kallikrein-kinin system was investigated. Two proteases, chymotrypsin-like (CHY) and trypsin-like (TRY) proteases, were activated in purified rat mast cells after degranulation with compound 48/80. Three fourths of the CHY activity remained in the cell residue, and the activity was inhibited by chymostatin, whereas most of the TRY activity was released in the medium and was inhibited by leupeptin. The incubation of rat or human plasma with degranulated mast cell (DMC) suspension did not cause the activation of plasma prekallikrein, but did cause a loss in the activity of coagulation factor XII, as ascertained by the lack of activation of prekallikrein in either the DMC-treated plasma by glass powder or in the incubation of DMC-treated human plasma with factor XII deficient plasma activated by kaolin. The prekallikrein and high-molecular-weight kininogen levels were sufficient for activation of factor XII.
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PMID:Loss of the activity of human coagulation factor XII by a chymotrypsin-like protease activated in rat mast cells during degranulation with compound 48/80. 330 14

A C3d-like (C3d-1) fragment of 33 kDa was isolated and its biological activity studied. The fragment was generated from guinea pig C3b by porcine pancreas kallikrein and purified by fast protein liquid chromatography. The C3d-like fragment inhibited interleukin (IL) 2-dependent T lymphocyte proliferation. The suppressive activity of the described C3d-1 fragment was not restricted to lymphocytes as targets but inhibited in addition the proliferation of a nonlymphocyte mast cell line which was strictly IL3-dependent in its proliferative capacity. Kinetic studies implied early stages of cellular proliferation to be influenced. Furthermore, the C3d-1 fragment was not only an inhibitor of cellular proliferation but was also a potent inducer of leukocytosis.
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PMID:Inhibition of interleukin 3 function by a fragment of the third component of complement. 349 44

Kallikrein was localized in goblet (or mucous) cells of rat colon and in rat and cat small intestine and stomach by two immunocytochemical techniques. A kallikrein-like enzyme was also localized by enzyme histochemistry in mast cells of colon, intestine, and stomach of the cat, where they appeared to be associated with blood vessels in the lamina propria. The mast cell enzyme, however, was not detected by immunocytochemistry using antibodies to kallikrein. Modification in the enzyme histochemical procedure (pH, fixation) yielded positive results for a kallikrein-like protease in goblet cells of the intestine and colon. The possible physiological and pathological significance of kallikrein-like enzyme in the gastrointestinal tract and elsewhere is discussed.
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PMID:Immunocytochemical and enzyme histochemical localization of kallikrein-like enzymes in colon, intestine, and stomach of rat and cat. 351 56

The vascular permeability-increasing action of rabbit PMNL lysosomes has been studied in skin and cremaster muscle of the rat. Both an extract of frozen-thawed granules and a cathepsin-free cationic protein fraction of the granules (which had previously been demonstrated to cause leukocyte adhesion and emigration in vivo) induce increased vascular permeability in skin and muscle which resembles that produced by histamine or histamine-liberators with respect to the timing of the response and the predominant type of microvessel affected. Extracts of frozen-thawed lysosomes and the inflammatory lysosomal cationic protein both cause disruption of rat mesenteric mast cells in vitro, whereas a granule-free cytoplasmic fraction of PMN leukocytes and a non-inflammatory cationic protein fraction of the granules do not do so under identical test conditions. The mastocytolytic action of lysosomal materials in vitro is not inhibited in the presence of 10 kallikrein-inhibiting units of trasylol per ml. The mast cell rupturing fraction of PMNL granules (cationic protein) possesses no detectable peroxidase activity or acid-mucopolysaccharase activity. When compared with compound 48/80 on the basis of estimated molecular weight, the lysosomal cationic protein appears to be at least as active as the latter compound with respect to in vitro mastocytolytic potency. Chronic pretreatment of rats with an agent known to reduce tissue mast cell numbers causes marked suppression of the vascular permeability change normally induced in skin and muscle by lysosomal extracts and cationic protein. Similar results are obtained if lysosomal materials are tested in rats pretreated with an antihistaminic. These observations are discussed with respect to the mode of action of PMNL lysosomes in the early and late phases of local tissue-injury reactions.
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PMID:Mediators of inflammation in leukocyte lysosomes. II. Mechanism of action of lysosomal cationic protein upon vascular permeability in the rat. 437 82

Tryptase, the major neutral protease of human pulmonary mast cell secretory granules, rapidly inactivates human high m.w. kininogen (HMWK) in vitro. HMWK (5600 nM) lost 50% of its capacity to release kinin in response to kallikrein after a 5-min incubation with tryptase (31 nM), even though kinin activity was neither generated nor, when bradykinin was incubated with tryptase, destroyed by tryptase. The procoagulant activity of HMWK (51 nM) and the purified procoagulant chain (40 nM) that is derived from HMWK were each 72% inactivated after 7 min of incubation with tryptase (0.04 nM and 0.02 nM, respectively). Human urinary and pancreatic kallikrein did not inactivate this procoagulant activity under conditions in which kinin generation occurs. Complete cleavage of native single-chain HMWK by tryptase occurred in less than 10 min as analyzed by electrophoresis in sodium dodecyl sulfate polyacrylamide slab gels. The major products formed during the initial 2 min were proteins of 100,000 and 95,000 apparent m.w., and by 10 to 30 min were fragments of 74,000 and 67,000 apparent m.w. Reduction of these cleavage products yielded two major fragments of 67,000 and 66,000 apparent m.w. that were both present by 0.17 min. The presence of lower m.w. products, thought to be primarily from the carboxy-terminal procoagulant region of HMWK, were also detected with and without reduction. The capacity of tryptase to inactivate HMWK is consistent with the ability of other mast cell-derived mediators, such as heparin proteoglycan and prostaglandin D2, to suppress blood coagulation and thrombosis, and may play an important role in the biology of mast cell-dependent events in vivo.
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PMID:Inactivation of human high molecular weight kininogen by human mast cell tryptase. 633 26

The generation of bradykinin by contact activation requires autoactivation of factor XII (Hageman factor) upon initiating surfaces, conversion of prekallikrein to kallikrein, and digestion of high-molecular-weight (HMW) kininogen. Endothelial cells have a high-affinity receptor that binds either HMW kininogen or factor XII in a zinc-dependent interaction, and activation of factor XII can occur along this surface to initiate kinin formation. Tissue injury, exposure of proteoglycans, or release of mast cell heparin will markedly accelerate these reactions. The bradykinin released binds to endothelial cell B-2 receptors along the inner surface of blood vessels which results in dilatation and increased vascular permeability.
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PMID:Assembly of the human plasma kinin-forming cascade along the surface of vascular endothelial cells. 761 24

During atherogenesis, lipid droplets appear in the extracellular space of the arterial intima. We previously observed generation of lipid droplets on the surface of exocytosed mast cell granules when granule neutral proteases degraded the granule-bound LDL particles and the particles became unstable and fused [Kovanen, P.T., & Kokkonen, J.O. (1991) J. Biol. Chem. 266, 4430-4436]. We have now extended our studies to the fluid phase and examined the effects of several proteases (trypsin, alpha-chymotrypsin, Pronase, plasmin, kallikrein, and thrombin) all known for their ability to cleave the apolipoprotein B-100 component (apoB-100) of LDL. The fused LDL particles were separated from unfused particles by gel filtration or by density gradient ultracentrifugation. Proteolytic degradation of LDL with trypsin, alpha-chymotrypsin, or Pronase led to fragmentation of apoB-100 and release of the fragments from the LDL particles and triggered particle fusion. In contrast, proteolytic degradation of LDL with plasmin, kallikrein, or thrombin, which also led to fragmentation of apoB-100 but not to release of fragments, did not trigger particle fusion. With advancing degradation of apoB-100, particles having progressively lower densities and larger sizes were generated. Thus, after incubation for 24 h with alpha-chymotrypsin (apoB-100:alpha-chymotrypsin mass ratio 10:1) 40% of the apoB-100 was degraded and about 30% of the LDL particles had fused and reached diameters of up to 70 nm and densities ranging from 1.020 to < 1.005 g/mL. When the proteolyzed LDL particles, both unfused and fused, were incubated with macrophages, only those particles that had undergone fusion were ingested and converted into intracellular cholesteryl ester droplets. Thus proteolysis of LDL with release of apoB-100 fragments renders the particles sufficiently unstable to fuse and thus to become liable to ingestion by macrophages. Since the fused LDL particles resemble the extracellular lipid droplets in the atherosclerotic arterial intima and generate foam cells in vitro, these findings support the idea that proteolytic fusion of LDL is an atherogenic process.
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PMID:Fusion of proteolyzed low-density lipoprotein in the fluid phase: a novel mechanism generating atherogenic lipoprotein particles. 764 Feb 66


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