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)

In vitro experimentation using dispersed human lung mast cells demonstrated that azatadine base, a compound with known H1-antihistamine properties, inhibited anti-IgE-induced release of histamine and leukotriene C4 by 45% and 85%, respectively. To assess the clinical relevance of these findings and to compare in vitro mast cell data with results obtained in vivo, nasally instilled azatadine was tested in a double-blind, placebo-controlled clinical trial in which nasal challenges with antigen were performed on eight allergic individuals. Pretreatment with azatadine significantly suppressed the number of sneezes following antigen challenge and inhibited the associated elevations in histamine, kinins, and enzyme(s) hydrolyzing the artificial substrate N-alpha-tosyl-L-arginine-methyl-ester in nasal secretions, whereas placebo was inactive. Hence, we showed agreement between our in vitro and in vivo experimental models of the allergic reaction. Topical application of azatadine base has the potential to become an effective antiallergic treatment.
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PMID:Demonstration of inhibition of mediator release from human mast cells by azatadine base. In vivo and in vitro evaluation. 241 58

A nasal challenge model of allergic rhinitis was used to determine if pretreatment with oral theophylline reduces histamine release in vivo. Ten subjects were entered into a double-blind, cross-over trial. The results showed that both the physiologic response (sneezing) (p = 0.02) and the amount of mediators (histamine, kinins, toluene sulfonyl arginine methyl ester esterase activity) (p less than 0.01 for all) released into nasal secretions were significantly reduced after one week of pretreatment with theophylline. At the time of challenge, the serum concentrations of theophylline were between 8 and 22 micrograms/ml. It is speculated that the ability of theophylline to block the clinical response to antigen challenge and to decrease the release of mast cell mediators contributes to its clinical efficacy in the treatment of asthma.
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PMID:Theophylline reduces the response to nasal challenge with antigen. 241 77

A new 28 amino acid peptide, we recently isolated from the venom of the bumblebee Megabombus pennsylvanicus. has been characterized. The peptide, Met-Cys-Ile-Cys-Lys-Asn-Gly-Lys-Pro-Leu-Pro-Gly-Phe-Ile-Gly-Lys-Ile-Cys- Arg-Lys-Ile-Cys-Met-Met-Gln-Gln-Thr-His(NH2), has been named bumblebee mast cell degranulating (MCD) peptide due to its ability to degranulate rat peritoneal mast cells, and its resemblance to the bee venom MCD peptide. Bumblebee MCD peptide, unlike bombolitins, the other mast cell degranulating heptadecapeptides of bumblebee venom, is not lytic and releases histamine at a dose as low as 0.05 micrograms/ml (1.6 X 10(-8) M).
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PMID:Amino acid sequence of bumblebee MCD peptide: a new mast cell degranulating peptide from the venom of the bumblebee Megabombus pennsylvanicus. 242 Dec 65

Proteases present in mast cell granules have been harnessed to demonstrate mast cells in human tissues. A number of substrate mixtures were tested. D-Val-Leu-Arg-4-methoxy-2-naphthylamide (MNA) plus Fast Blue B was the best for identifying human mast cells, yielding the most specific and complete staining. The procedure is simple and the results are permanent. Cryostat sections of aldehyde-fixed routine preparations or paraffin sections of Carnoy-fixed tissues give the most satisfactory results. Mast cells are stained a strong red color that stands out distinctly from the surrounding tissues, so that they can be easily identified by simple microscopy. A double-staining technique, first for protease and subsequently using Alcian Blue, showed that as progressive protease staining occurs, the alcianophilia of mast cells is lost. This procedure demonstrated that mast cells in the mucosa of human gut generally required longer incubations to develop protease staining than in other connective tissue sites. In post-mortem tissues, mast cells retain their protease activity well and so can be demonstrated in cryostat sections of aldehyde-fixed material, giving a more complete picture than with Alcian Blue. The synthetic substrate D-Val-Leu-Arg-MNA can be recommended for routine identification of mast cells in human tissues.
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PMID:Selection of a simple protease procedure for identifying mast cells in routinely processed human tissues. 243 82

The appearance and activity of various porcine pancreatic hydrolases were studied during fetal and postnatal development. Quantitatively, the enzyme activities in activated pancreas homogenates were low but increased during the second half of the fetal period, using the substrates Bz-Arg-pNA for measuring anodal and cathodal trypsin, Suc-Phe-pNA (chymotrypsin A and C, and elastase II) and Suc-(Ala)3-pNA (elastase I and protease E). Postnatally, after an initial decrease during the first week, the enzyme activities increased markedly, especially from 10-14 weeks to 6 months. The individual hydrolases were identified after electrophoretic separation in agarose gel and staining with various substrates either directly in the gel or after transfer to nitrocellulose membranes (enzymoblotting). During the fetal period, chymotrypsin A and B, elastase II, carboxypeptidase A, and amylase appeared at approximately 65 days and anodal trypsin, at approximately 76 days. After birth, new proteinases appeared after the first week including chymotrypsin C, cathodal trypsin, and protease E, whereas elastase I was found from 5 weeks after birth. Concomitantly, unidentified "fetal proteinase(s)" with caseinolytic, Ac-Phe-beta NE and CBZ-Ala-beta NE activities began to diminish and disappeared 10-14 weeks after birth. This study showed a marked increase in the overall pancreatic enzyme activities, as well as an age-dependent expression of the variety of pancreatic hydrolases during porcine ontogeny.
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PMID:Development of porcine pancreatic hydrolases and their isoenzymes from the fetal period to adulthood. 244 72

The ability of purified anaphylatoxins to induce human lung mast cell mediator release was investigated. In eight anti-IgE responsive (histamine release = 22 +/- 5%, mean +/- SEM) mast cell preparations of 1-96% purity, C5a and C5a des Arg (0.55 pg/ml to 55 micrograms/ml), failed to elicit or potentiate histamine release; lung fragments were similarly unresponsive. The related peptide C3a was also inactive. All anaphylatoxins failed to induce mast cell leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) release. LTC4 release was also negligible from basophils where C5a was a potent histamine release stimulus. Supernatants from C5a-challenged mast cells remained fully active on basophils, excluding carboxypeptidase inactivation of C5a as an explanation for the lung mast cell results. In contrast to lung, skin mast cells were C5a-responsive (histamine release = 8 +/- 1%, at 55 micrograms/ml, n = 2). We conclude that C5a, though devoid of activity on the human lung mast cell, is a human basophil and skin mast cell secretagogue. These findings demonstrate significant organ-specific heterogeneity in mast cell responsiveness.
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PMID:Differential effects of the complement peptides, C5a and C5a des Arg on human basophil and lung mast cell histamine release. 244 62

The acid proteases, pepsin, rennin and cathepsin D, were shown to generate mast cell histamine releasing peptides (HRP) when incubated with the albumin fraction of mammalian plasmas. Significant histamine release was observed using less than 1 microliter equivalent of pepsin-treated plasma. Histamine release was rapid, dependent on calcium and energy, and accompanied by degranulation. The major HRP present in pepsin-treated human and canine plasma was identified as H-Ile-Ala-Arg-Arg-His-Pro-Tyr-Phe-OH whereas that from rat plasma had valine substituted for isoleucine. Cathepsin D-treated BSA gave rise to the human octapeptide (above) as well as to an extended decapeptide with H-Tyr-Glu- at the N-terminus. These peptides were apparently derived from one region of serum albumin, residues 139 to 149 of the human, canine, or bovine sequence. We hypothesize that cathepsin D, released from leukocyte lysosomes, might generate HRP during the delayed phase of an inflammatory response.
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PMID:Structures of histamine-releasing peptides formed by the action of acid proteases on mammalian albumin(s). 247 9

A series of substance P (SP)- and bradykinin (BK)-related peptides have been compared for their histamine-releasing activities on rat peritoneal mast cells. Some of these peptides only differed in the N-acetylation of the N-terminal arginine residue or by the removal of charged residue at the N-terminal. The aim was to examine the role of the N-terminal positive charges in the histamine-releasing activity of compounds that are selective for the SP receptor (named NK-1) or for the B2 type bradykinin receptor. Only compounds with positive charges at the N-terminal caused non-cytotoxic histamine release from rat mast cells. It is suggested that SP- and BK-related peptides caused histamine release by a mechanism which appeared to be non-specific and not related to the activation of mast cell NK-1 or B2 receptors, respectively. Our results show that NK-1 agonists or B2 antagonists devoid of histamine-releasing activity, which could be of potential use in the clinic, can be obtained by removing the positively charged N-terminal aminoacids or by N-acetylation of the N-terminal arginine.
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PMID:Role of the N-terminal arginine in the histamine-releasing activity of substance P, bradykinin and related peptides. 247 72

Mast cell tryptase is a secretory granule associated serine protease with trypsin-like specificity released extracellularly during mast cell degranulation. To determine the full primary structure of the catalytic domain and precursor forms of tryptase and to gain insight into its mode of activation, we cloned cDNAs coding for the complete amino acid sequence of dog mast cell tryptase and a second, possibly related, serine protease. Using RNA from dog mastocytoma cells, we constructed a cDNA library in lambda gt 10. Screening of the library with an oligonucleotide probe based on the N-terminal sequence of tryptase purified from the same cell source allowed us to isolate and sequence overlapping clones coding for dog mast cell tryptase. The tryptase sequence includes the essential residues of the catalytic triad and an aspartic acid at the base of the putative substrate binding pocket that confers P1 Arg and Lys specificity on tryptic serine proteases. The apparent N-terminal signal/activation peptide terminates in a glycine. A glycine in this position has not been observed previously in serine proteases and suggests a novel mode of activation. Additional screening of the library with a trypsinogen cDNA led to the isolation and sequencing of a full-length clone apparently coding for the complete sequence of a second tryptic serine protease (DMP) which is only 53.4% identical with the dog tryptase sequence but which contains an apparent signal/activation peptide also terminating in a glycine. Thus, the proteases encoded by these cloned cDNAs may share a common mode of activation from N-terminally extended precursors.
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PMID:Molecular cloning of dog mast cell tryptase and a related protease: structural evidence of a unique mode of serine protease activation. 250 77

C5a and its degradation product, C5a des Arg, elicit immediate cutaneous inflammatory reactions after intradermal injection. Histologically, these reactions are characterized by neutrophil-rich leukocytic infiltrates, leukocytoclasis, edema, and dermal mast cell degranulation. It has not been possible to assess in vivo the relative contributions of resident mast cells and circulating leukocytes to this reaction because the accumulation of leukocytes and degranulation of mast cells occur simultaneously after injection of these anaphylatoxins. To assess the role of mast cells in these inflammatory reactions, we have examined the reactivity of human skin selectively depleted of dermal mast cells by local corticosteroid treatment. Corticosteroid-treated skin became virtually devoid of dermal mast cells within 4-6 wk as assessed by light microscopy, immunofluorescence with fluorescein-conjugated avidin, or electron microscopy. Mast cell-depleted skin demonstrated normal vasopermeability and vasodilatory responsiveness to intradermal injection of histamine, but the reactivity of these sites to the mast cell secretagogue, morphine, was absent. Moreover, no clinical reactions were detectable in mast cell-depleted human skin after intradermal challenge with 50 ng of either C5a or C5a des Arg, despite the fact that biopsies of these sites revealed substantial, neutrophil-rich infiltrates. These infiltrates were qualitatively and quantitatively identical to C5a or C5a des Arg-induced infiltrates in mast cell replete skin. This experimental approach in vivo has allowed the independent analysis of the anaphylactogenic and chemoattractant activities of human C5a and C5a des Arg in human skin, demonstrated the importance of dermal mast cells in these clinical responses, and shown that leukocytes can accumulate at these injection sites directly in response to these mediators.
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PMID:Inflammatory properties of human C5a and C5a des Arg/ in mast cell-depleted human skin. 231 20


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