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)

The existence of saturable and specific binding sites for mouse P40/IL-9 was demonstrated on a variety of factor-dependent T cell lines derived from Th clones by long term culture in the presence of P40-containing T cell supernatants. Scatchard transformation of the data obtained with one such line was consistent with the existence of a single class of receptors with a Kd of approximately 100 pM and a density of 3000/cell. P40 binding to these cells was followed by rapid internalization of the ligand. P40-receptors (P40-R)3 were also found on certain Th clones maintained in conventional cultures, especially after stimulation with Ag and APC. Only T cell clones that proliferated in response to P40 showed significant levels of binding, suggesting that the regulation of P40-R expression is an important element in the control of P40-responsiveness. In accord with this idea, fresh T cells, cytolytic T cell clones and a wide variety of other cells including B cells and fibroblasts, which do not proliferate in response to P40, showed no significant binding. However, P40-R were not restricted to a few unusual Th clones. They were also detected on several T cell tumors, on macrophages and on mast cell lines. The latter point is of particular interest in view of the mast cell growth factor activity recently ascribed to P40. Cross-linking studies with T-cell lines and mast cells indicated that the P40-R consists of a 64-kDa glycoprotein, the molecular mass of which is reduced to 54 kDa on treatment with N-glycosidase F.
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PMID:Functional and biochemical characterization of mouse P40/IL-9 receptors. 214 61

The complete covalent structure of protein C, a protein degraded during germination of Bacillus megaterium spores, has been determined. The intact protein was cleaved with a highly specific spore protease into two peptides, residues 1 to 30 and 31 to 71. The intact protein was also cleaved by cyanogen bromide into two peptides, residues 1 to 27 and 28 to 71. Cleavage of the larger cyanogen bromide peptide with trypsin allowed isolation of the COOH-terminal peptide, residues 59 to 71. Automated sequenator analysis of the intact protein and peptide fragments, together with previously published partial sequence data on this protein and carboxypeptidase A digestion of the intact protein provided data from which the following unique sequence was deduced: (formula: see text). The primary sequence of the C protein shows an extremely high degree of homology with that of the A protein--another protein degraded during germination of B. megaterium spores.
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PMID:Covalent structure of protein C. A second major low molecular weight protein degraded during germination of Bacillus megaterium spores. 677 41

Tryptase, a mast cell serine protease, has been implicated in the pathophysiology of allergic asthma, but formal evidence to support this hypothesis has been limited by the lack of specific inhibitors for use in vivo. Therefore, in this study we examined the effects of two inhibitors of tryptase, APC 366 [N-(1-hydroxy-2-naphthoyl)-L-arginyl-L-prolinamide hydrochloride] and BABIM [bis(5-amidino-2-benzimidazolyl)methane] on antigen-induced early and late responses, airway responsiveness as measured by carbachol provocation, microvascular permeability as measured by bronchoalveolar lavage (BAL) albumin concentrations, and tissue eosinophilia from biopsies in allergic sheep. APC 366 and BABIM were administered by aerosol in all experiments. In vehicle control trials, antigen challenge resulted in peak early and late increases in specific lung resistance (SRL) of (mean +/- SE, n = 6) 259 +/- 30% and 183 +/- 27% over baseline, respectively. Treatment with APC 366 (9 mg/3 ml H2O given 0.5 h before, 4 h after, and 24 h after antigen challenge) slightly reduced the peak early response (194 +/- 41%), but significantly inhibited the late response (38 +/- 6%, p < 0.05 versus control trials). Twenty-four hours after challenge, APC 366 also completely blocked the antigen-induced airway hyperresponsiveness to inhaled carbachol observed in the control trial.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tryptase inhibitors block allergen-induced airway and inflammatory responses in allergic sheep. 852 Jul 78

Tryptase (EC 3.4.21.59), the major secretory product of human mast cells, has become widely used as a biochemical marker for mast cells and mast cell activation, and is attracting attention as a mediator of allergic disease. However, there is little information available on the properties, or even the presence, of this protease in commonly used species of laboratory animals. We, here, report the demonstration and characterisation of this enzyme in the guinea pig lung. Tryptic activity resistant to alpha 1-proteinase inhibitor and soybean trypsin inhibitor was detected in sections of guinea pig lung tissue with the histochemical substrate Z-Gly-Pro-Arg-MNA. It was localised to mast cells and appeared to be present in all mast cells staining with Alcian Blue. A tryptic protease was purified 2400-fold from whole lung tissue by high salt extraction, cetylpyridinium chloride precipitation, heparin agarose chromatography, and gel filtration. This enzyme was found to be multimeric with a subunit of 38 kDa and a native molecular mass of 860 +/- 100 kDa. Inhibitor studies identified it as a serine protease. Like human tryptase, it was inhibited by leupeptin, benzamidine, and APC 366 (N-(1-hydroxy-2- naphthoyl)-L-arginyl(-L-prolinamide hydrochloride), but not by alpha 1-proteinase inhibitor, soybean trypsin inhibitor, or antithrombin III. Its response to changes in pH and ionic strength was similar to that of human tryptase. Differences between the guinea pig and human enzymes were seen in activity toward a panel fo 10 tryptic p_nitroanilide peptide substrates. Kinetic constants were determined for two of these: with L-Pyr-Pro-Arg-pNA the guinea pig tryptase had a similar Km but a 5-fold lower kcat than human tryptase, and with L-Pyr-Gly-Arg-pNA the guinea pig enzyme had a 10-fold lower Km and a 30% greater kcat than human counterpart. Heparin stabilised guinea pig tryptase, but did not alter its kinetic parameters as it did with human tryptase, decreasing the Km towards both substrates. The presence of a protease with similarities to human tryptase in the mast cells of guinea pigs suggests that this species may be an appropriate model to investigate the actions to tryptase in vivo, provided cognizance is taken of the differences that do exist.
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PMID:Guinea pig lung tryptase. Localisation to mast cells and characterisation of the partially purified enzyme. 869 58

Allergen-induced bronchoconstriction involves mast cell activation. Tryptase is a mast cell serine protease that is released during this process, but little is known about the action of tryptase in the airway. The purpose of this study was to determine: (1) if aerosolized tryptase causes bronchoconstriction, and (2) the mechanism by which this occurs. We measured mean pulmonary flow resistance (RL) in five allergic sheep before and after consecutive inhalations of 100 and 500 ng tryptase (in 2 ml total volume). Inhaled tryptase at 100 and 500 ng increased RL (mean +/- SE) by 33 +/- 12 and 122 +/- 8% (p < 0.05) over baseline. The response was reproducible upon repeat challenges. These studies were repeated in the same animals after pretreatment with aerosolized APC 366 (9 mg/3 ml), a specific tryptase inhibitor. In APC-366-treated sheep, tryptase increased RL by 10 +/- 3 and 6 +/- 2% (p < 0.05 versus control values) at 100 and 500 ng, respectively. The response to tryptase was also blocked by pretreating the sheep intravenously with the histamine H1-antagonist chlorpheniramine (2 mg/kg), in which RL increased only 5 +/- 4 and 7 +/- 6% after 100 and 500 ng tryptase. APC 366, however, did not block histamine-induced bronchoconstriction. Consistent with these findings was the observation that segmental bronchial challenge with tryptase (1 microgram) resulted in a significant increase in histamine levels in bronchoalveolar lavage. Inhaled tryptase (500 ng) also caused airway hyperresponsiveness to aerosolized carbachol 2 h after tryptase challenge. This tryptase-induced airway hyperresponsiveness could be blocked either by pretreating the sheep with APC 366 (30 min before challenge) or by treating the sheep 30 min after challenge. These results indicate that inhaled tryptase causes bronchoconstriction and airway hyperresponsiveness in allergic sheep by an event that may involve mast cell activation.
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PMID:Inhaled tryptase causes bronchoconstriction in sheep via histamine release. 881 Jun

Thrombin-activatable fibrinolysis inhibitor (TAFI) is the precursor of an exopeptidase that is identical to plasma procarboxypeptidase B. Upon activation by thrombin, activated TAFI (TAFIa) attenuates fibrinolysis, presumably by catalyzing the removal of C-terminal lysines from partially degraded fibrin. Activated protein C (APC) proteolytically inactivates the essential cofactor in prothrombinase, factor Va, and limits both the formation of thrombin and subsequent activation of TAFI, thereby appearing profibrinolytic. TAFI is able to reconstitute an APC-dependent shortening of lysis time in a purified system; however, it remained to be determined the extent to which TAFI is involved in the profibrinolytic effect of APC in a plasma-based system. To aid in addressing this question, two monoclonal antibodies (MoAbTAFI#16 and #13) and a polyclonal antibody were produced against purified TAFI. MoAbTAFI#16 was shown to inhibit TAFI activation and thereby appears to stimulate fibrinolysis. Furthermore, an enzyme-linked immunosorbent assay was developed using MoAbTAFI#13 and the polyclonal antibody. Through its use, the plasma concentration of TAFI was determined to be 73 nmol/L. In addition, a turbidity assay was used to determine the effect of APC on tissue plasminogen activator-induced fibrinolysis of clots produced from normal human plasma (NHP), plasma immunodepleted of TAFI (TdP), and TdP reconstituted with purified TAFI. APC shortened lysis time of clots produced from NHP in a saturable and concentration-dependent manner. However, APC had no effect on lysis time of clots formed from either TdP or NHP in the presence of 80 nmol/L MoAbTAFI#16. The APC effect could be reconstituted in TdP by the addition of purified TAFI. The lysis time in TdP was increased from 50 to 180 minutes in a TAFI concentration-dependent manner. The EC50 was 15 nmol/L and saturation was approached at physiologically relevant concentrations (60 nmol/L). The profibrinolytic effect of APC was also compared with that of MoAbTAFI#16 and two competitive inhibitors, an inhibitor of the carboxypeptidase A and B family purified from potato tubers and 2-Guanidinoethylmercaptosuccinic acid (GEMSA). All were able to reduce lysis time of clots formed from normal human plasma by 90 minutes, yielding respective EC50 values of 5 nmol/L, 15 nmol/L, 50 nmol/L, and 90 mumol/L. Therefore, the majority of the profibrinolytic effect of APC, in an in vitro plasma system, is dependent on TAFI. Because TAFIa dramatically influences lysis time, inhibitors of TAFIa or TAFI activation may prove to be important adjuvants for thrombolytic therapy.
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PMID:The profibrinolytic effect of activated protein C in clots formed from plasma is TAFI-dependent. 882 28

In this study, we used a specific tryptase inhibitor, APC-366 [N-(1-hydroxy-2-napthoyl)-L-arginyl-L- prolinamide hydrochloride] to investigate the effect of intradermally administered tryptase and tryptase released by antigen challenge on the immediate cutaneous reaction (ICR) in allergic sheep. The surface areas of cutaneous wheals produced by intradermal injections (0.05 ml) of 1 and 10 ng tryptase alone, tryptase combined with 3 U heparin (tryptase-heparin), or Ascaris suum antigen (10(-5) dilution) with or without pretreatment with APC-366 (1 mg/ml) were measured at 20 and 60 min after challenge. Intradermal injections of 1 and 10 ng tryptase alone (n = 7) produced an ICR of < or = 20% of that obtained after injection of histamine (5% wt/vol). Intradermal injection of tryptase-heparin (n = 7), however, resulted in 50 (1 ng) and 82% (10 ng) of the ICR to histamine (both, P < 0.05 vs. tryptase alone). APC-366 inhibited (P < 0.05) the ICR to 1 and 10 ng tryptase-heparin by > or = 70% at all times (n = 8) but had no effect on the histamine-induced ICR (n = 3). A combination of the histamine H1 antagonist chlorpheniramine (2 mg/kg iv) and the H2 antagonist metiamide (3 mg/kg iv) given 40 min before challenge (n = 8) inhibited the response to 1 and 10 ng tryptase-heparin by 42 and 62% at 20 min and by 96 and 86% at 60 min, respectively (all, P < 0.05). APC-366 also blocked the ICR to A. suum antigen by 68% (P < 0.05) in nine sheep. These results indicate that intradermal injection of tryptase-heparin can induce an ICR. This ICR can be inhibited by APC-366 or a combination of the histamine H1 and H2 antagonists, suggesting that the tryptase response is mediated by histamine. APC-366 also blocks the mast cell-mediated ICR to intradermally injected A. suum antigen. Collectively, these results suggest that tryptase may modulate mast cell histamine release.
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PMID:Role of tryptase in immediate cutaneous responses in allergic sheep. 884 61

Tryptase, a serine protease, is the major protein component in mast cells. In an animal model of asthma, tryptase has been established as an important mediator of inflammation and late airway responses induced by antigen challenge. Human tryptase is notable for its tetrameric structure, requirement of heparin for stability, and resistance to endogenous inhibitors. Human protryptase was expressed as a recombinant protein in Pichia pastoris. The recombinant protein consisted of two forms of protryptase, one containing the entire propeptide and the other containing only the Val-Gly dipeptide at its amino terminus. Isolation of active recombinant tryptase required a two column purification protocol and included a heparin- and dipeptidyl peptidase I-dependent activation step. Purified recombinant tryptase migrated as a tetramer on a gel filtration column and displayed kinetic parameters identical to those of a native tryptase obtained from HMC-1 cells, a human mast cell line. Recombinant and HMC-1 tryptase exhibited comparable sensitivities to an array of protein and low-molecular-weight inhibitors, including one that is highly specific for tryptase (APC-1167). Similarly, the recombinant enzyme cleaved both alpha- and beta-chains of fibrinogen to generate fibrinogen fragments indistinguishable from those generated by HMC-1-derived tryptase. Thus, recombinant tryptase expressed in P. pastoris displays physical and enzymatic properties essentially identical to the native enzyme. This system provides a cost-effective and easy to manipulate expression system that will enable the functional characterization of this unique enzyme.
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PMID:Expression and characterization of recombinant mast cell tryptase. 1009 84

Human tryptase is a structurally unique and mast cell specific trypsin-like serine protease. Recent biological and immunological investigations have implicated tryptase as a mediator in the pathology of numerous allergic and inflammatory conditions including rhinitis, conjunctivitis, and most notably asthma. A growing body of data further implicates tryptase in certain gastrointestinal, dermatological, and cardiovascular disorders as well. The recent availability of potent, and selective tryptase inhibitors, though, has facilitated the validation of this protease as an important therapeutic target as well. Herein, we describe the design and potency of four classes of selective tryptase inhibitors, of which the first three types are synthetic and the fourth is natural in origin: 1) peptidic inhibitors (e.g., APC-366), 2) dibasic inhibitors (i.e., pentamidine-like), 3) Zn(2+)-mediated inhibitors (i.e., BABIM-like), and 4) heparin antagonists (e.g., lactoferrin). These inhibitors have been tested in the airways and skin of allergic sheep. Aerosol administration of tryptase inhibitors from each structural class 30 minutes before, and 4 hours and 24 hours after allergen challenge, abolishes late phase bronchoconstriction and airway hyperresponsiveness in a dose-dependent manner. Moreover, intradermal injection of APC-366 blocks the cutaneous response to antigen. These studies provide the essential proof-of-concept for the further pursuit of tryptase inhibitors for the treatment of asthma, and perhaps other allergic diseases. Results from clinical studies with the first generation tryptase inhibitor APC-366, currently in phase II trials for the treatment of asthma, provide additional support for a pathological role for tryptase in this disease. Notable advances in the area of tryptase inhibitor design at Axys Pharmaceuticals, Inc. include a novel, zinc-mediated, serine protease inhibitor technology (described herein), and the discovery of a unique class of extremely potent and selective dibasic tryptase inhibitors. Independently, an X-ray crystal structure of active tryptase tetramer complexed with 4-amidinophenyl pyruvic acid has been reported. It is anticipated that these discoveries will further accelerate the design of structurally novel tryptase inhibitors as well as the development of new drugs for the treatment of mast cell tryptase-mediated disorders.
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PMID:Inhibitors of tryptase for the treatment of mast cell-mediated diseases. 1019 50

Receptors that display negative signalling functions on lymphocytes and other cells of the reticuloendothelial system now number about 30. These negative receptors are transmembrane glycoproteins activated by phosphorylation of a tyrosine residue in immunoreceptor tyrosine-based inhibitory motifs that bind various phosphatases to induce dominant negative signals. Since these receptors are armed by the action of activating receptors and inhibit signalling by activating receptors, we have termed them coinhibitory receptors and the negative outcome is coinhibition. Coinhibitory receptors and some inhibitory mediators include FcgammaRIIB, CTLA-4, CD5, CD22, p58/70/140 KIR, gp49B1/gp91, PIRB1-5, LAIR-1, NKB1, Ly49 A/C/E/F/G, NKG2-A/B APC-R, CD66, CD72, PD-1, SHPS-1, SIRP-alpha1, ILT1-5, MIR7, 10, hMIR(HM18), hMIR(HM9), LIR1-3,5,8, Fas (CD95), TGFbeta-R, TNF-R1, IFNgamma-R (alpha and beta chains), mast cell function Ag, H2-M, HLA-DM, CD1, CD1-d, CD46, c-cbl, Pyk2/FADK2, P130 Ca rel prot, PGDF-R, LIF, LIF-R, CIS, SOCS13 and 5, and others are being defined regularly. This long list suggests that coinhibitors are needed not only for self-nonself discrimination, but also for control of ongoing responses to foreign antigens so that infectious agents are ideally dealt with by an appropriate level of immune responses to nonself and an appropriate amount of immunopathology and sickness behaviour.
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PMID:Why so many coinhibitory receptors? 1040 45


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