UMLS:C0043167 - FACTA Search

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Query: UMLS:C0043167 (pertussis)
19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In active anaphylactic shock of rats pretreated with Bordetella pertussis vaccine, both plasma thrombin clotting time and the amount of antigenically active fibrinogen degradation products in the serum were increased. The formation of clottable fibrinogen fragments was shown by SDS polyacrylamide gel electrophoresis of thrombin-induced clots. When plasma of rats pretreated with 125I rat fibrinogen and then subjected to anaphylaxis was submitted to SDS polyacrylamide gel electrophoresis, fibrinogen-split products were also detected. Fibrinogen degradation results from the proteolytic effect of an activated fibrinolytic enzyme.
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PMID:Evidence of fibrinogen degradation in rat anaphylaxis. 115 26

Thrombin at concentrations as low as 20 pM (0.002 U ml-1) was found to stimulate inositol phosphate levels in cultured human non-pigmented ciliary epithelial cells. Several other proteases, including trypsin and plasmin, had little or no effect, of several protease inhibitors tested, only those with specificity for thrombin blocked the effect. Studies with active site-blocked thrombin suggested that the esterolytic active site of thrombin is required for inositol phosphate stimulation, while gamma-thrombin, which has reduced binding affinity to fibrinogen also showed reduced effectiveness in stimulating inositol phosphates. In the presence of 10 mM LiCl, thrombin stimulated inositol monophosphate, inositol bisphosphate and inositol trisphosphate formation, with a prolonged rise of the first and transient early rises in the latter two species. Thrombin also elevated intracellular Ca2+ levels as measured with the fluorescent calcium probe, indo-1-AM. This elevation could be blocked by prior addition to cells of the thrombin inhibitor, hirudin, and was dependent upon extracellular Ca2+ for the maintenance of an elevated level in the presence of thrombin. Incorporation of thymidine into DNA in confluent cultures was also stimulated by thrombin, with a four-fold increase in incorporation at 35 hr in thrombin-treated cells compared to controls. The half-maximal concentration for this process was 0.25 U ml-1. Pretreatment with 100 ng ml-1 pertussis toxin greatly reduced the thrombin effect, which is consistent with a role for a G-protein in stimulation of DNA synthesis by thrombin.
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PMID:Thrombin stimulates inositol phosphate formation, intracellular calcium fluxes and DNA synthesis in cultured fetal human non-pigmented ciliary epithelial cells. 148 37

Following platelet activation, surface receptors for fibrinogen are exposed. On the activated platelet, glycoprotein IIb-IIIa (GPIIb-IIIa) serves as the receptor for fibrinogen. However, the molecular mechanisms which regulate GPIIb-IIIa fibrinogen receptor exposure are unknown. D3GP3 is an IgG1, kappa monoclonal antibody which is specific for glycoprotein IIIa (GPIIIa). The binding of D3GP3 to GPIIIa, in intact GPIIb-IIIa complexes, induces fibrinogen binding and platelet aggregation. To determine if D3GP3 binding to GPIIIa directly caused the exposure of fibrinogen receptors or, secondarily, due to stimulus response coupling, platelet activation parameters were monitored following the addition of D3GP3 to platelets suspensions. D3GP3 binding did not induce detectable Ca++ mobilization, protein phosphorylation or activation of the pertussis toxin sensitive G-protein subunit alpha-41. Further, D3GP3-induced aggregation was not blocked by PGE1, aspirin, apyrase or the combination of all three reagents. Scanning electron microscopy of D3GP3-induced aggregates demonstrated that the aggregates were composed of discoid platelets. These data suggest that the binding of D3GP3 to GPIIIa induced a conformational change in GPIIb-IIIa such that the fibrinogen receptor was exposed in an activation-independent fashion. This provides evidence that conformational changes in the GPIIb-IIIa complex can result in the transformation of the complex to the high affinity binding competent state.
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PMID:Activation-independent exposure of the GPIIb-IIIa fibrinogen receptor. 195 76

We have used platelets permeabilized with saponin to examine the mechanism by which platelet activation causes the exposure of surface receptors for fibrinogen. Receptor exposure was detected using 125I-fibrinogen and 125I-PAC1, a monoclonal antibody specific for the activated form of the fibrinogen receptor. The potential mediators that were studied included guanyl-5'-yl imidodiphosphate (Gpp(NH)p) and guanosine 5'O-(thiotriphosphate) (GTP gamma S), which cause G protein-dependent phospholipase C activation in platelets; inositol 1,4,5-triphosphate (IP3), which causes Ca2+ release from the platelet dense tubular system; and diacylglycerol and phorbol ester, which activate protein kinase C. Each of these molecules caused fibrinogen and PAC1 binding. The effect of IP3 was mimicked by raising the cytosolic free Ca2+ concentration in the permeabilized platelets. However, IP3 and Ca2+-induced PAC1 binding were abolished by indomethacin or aspirin, which had no effect on PAC1 binding caused by Gpp(NH)p, phorbol ester, or diacylglycerol. This suggests that the response to IP3 and Ca2+ is due to the formation of metabolites of arachidonic acid. One such metabolite, TxA2, is believed to activate platelets by stimulating G protein-dependent phosphoinositide hydrolysis. Indeed, we found that the G protein inhibitor guanyl-5'-yl thiophosphate (GDP beta S) inhibited PAC1 binding caused by a thromboxane A2 analog (U46619), IP3, and Ca2+, but had no effect on diacylglycerol or phorbol ester-induced PAC1 binding. Thrombin-induced PAC1 binding and phosphoinositide hydrolysis were also inhibited by GDP beta S and by pertussis toxin. Increasing the thrombin concentration overcame the inhibition of PAC1 binding caused by GDP beta S but did not overcome the inhibition of phosphoinositide hydrolysis. These observations demonstrate that fibrinogen receptor exposure occurs by at least two routes. One of these, in response to agonists such as thrombin and U46619, is initiated by G protein-dependent phosphoinositide hydrolysis and involves the formation of IP3 and diacylglycerol. IP3 appears to act by stimulating Ca2+-dependent arachidonic acid metabolism which, in turn, triggers further phosphoinositide hydrolysis. Diacylglycerol acts by stimulating protein kinase C. A second route is activated by high concentrations of thrombin and is independent of phosphoinositide hydrolysis.
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PMID:Induction of the fibrinogen receptor on human platelets by intracellular mediators. 310 May 33

The activation of phospholipase C in human platelets is coupled to agonist receptors via guanine nucleotide-binding protein(s), and prior treatment of permeabilized platelets with GTP gamma S, GDP beta S, or pertussis toxin modifies platelet responses to agonists. Pertussis toxin is thought to act primarily as an uncoupler of Gi from cell receptors due to its ADP-ribosylating activity. However, we have found that pertussis toxin by itself can act as an agonist for intact or permeabilized platelets. Though believed to lack receptors for pertussis toxin, intact platelets, when incubated with the toxin (5-20 micrograms/ml), undergo aggregation and accumulate inositol trisphosphate and phosphatidic acid. Treatment of platelets with aspirin, incubation in the presence of creatine phosphate/creatine phosphokinase, or omission of Ca2+ and fibrinogen do not affect toxin-mediated phospholipase C activation. These effects are not observed with the ADP-ribosylating S1 monomer of toxin in intact or permeabilized platelets. Further, modification of the holotoxin with N-ethylmaleimide eliminates the toxin's ADP-ribosylating activity but does not affect its promotion of platelet aggregation and phospholipase C activation. Therefore, the activating effect of holotoxin is separable from its ADP-ribosylating activity and does not depend either upon cyclooxygenase or the ADP that may be released during platelet activation. Given the combined potentially stimulatory and inhibitory effects of pertussis holotoxin, we suggest caution in interpretation of results with this material.
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PMID:Pertussis toxin can activate human platelets. Comparative effects of holotoxin and its ADP-ribosylating S1 subunit. 366 9

Previous in vivo and in vitro studies demonstrated that the murine beta-chemokine TCA3 is a chemoattractant for monocytes/macrophages and neutrophils. The ability of TCA3 to activate these cell populations is now evaluated. Treatment with 10 to 20 nM rTCA3 induced a respiratory burst with the production of superoxide and hydrogen peroxide in both casein-elicited and unstimulated neutrophil and macrophage populations. In addition, TCA3 treatment induced the production of reactive nitrogen intermediates, whereas stimulation with higher concentrations (100 nM) of TCA3 induced the exocytosis of lysozyme and elastase in the presence of cytochalasin B (7 micrograms/ml). Subnanomolar concentrations (100 pM) of TCA3 also caused integrin-mediated increases of adhesiveness to fibrinogen by neutrophils and macrophages. Increased adhesiveness is the most sensitive assay for TCA3 bioactivity. TCA3 treatment appears to involve signaling through a G-protein-linked receptor as Pertussis toxin abolished the TCA3-mediated increase of adhesiveness and the production of reactive nitrogen intermediates. The dose dependence of the TCA3-mediated activities indicate a coordinated inflammatory response mediated by varying concentrations of TCA3.
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PMID:Biologic activities of the beta-chemokine TCA3 on neutrophils and macrophages. 773 Jun 38

Intracellular Ca2+ responses to extracellular matrix molecules were studied in suspensions of pancreatic acinar cells loaded with Fura-2. Collagen type I, laminin, fibrinogen and fibronectin were unable to raise cytosolic free Ca2+ concentration ([Ca2+]i), whereas collagen type IV, at concentrations from 5 to 50 micrograms/ml, significantly increased it. The effect of collagen type IV was not due to possible contamination with type-I transforming growth factor beta or plasminogen, as neither of these agents was able to increase [Ca2+]i. Using highly specific mass assays, concentrations of inositol lipids, 1,2-diacylglycerol (DAG) and Ins(1,4,5) P3 were measured in pancreatic acinar cells stimulated with collagen type IV. A decrease in the concentrations of PtdIns(4,5) P2 and PtdIns4 P with a concomitant increase in the concentrations of DAG and InsP3 mass were observed, showing that collagen type IV increases [Ca2+]i by activation of phospholipase C. The observed [Ca2+]i signals had two components, the first resulting from Ca2+ release from the intracellular stores, and the second resulting from Ca2+ flux from the extracellular medium through the verapamil-insensitive channels. A tyrosine kinase inhibitor (tyrphostine) was able to block inositol lipid signalling caused by collagen type IV, which together with the insensitivity of this pathway to cholera toxin and pertussis toxin or to preactivation of protein kinase C, the longer duration of the increase in [Ca2+]i and a longer lag period needed for observation of increases in DAG and InsP3 concentration with collagen type IV than with carbachol (50 mM) suggest that activation of phospholipase C by collagen type IV is caused by tyrosine kinase activation. Inositol lipid signalling and increases in [Ca2+]i were also observed with Arg-Gly-Asp (RGD)-containing peptide but not with Arg-Asp-Gly (RDG)-containing peptide. Collagen type IV and RGD-containing peptide, but not carbachol, competed in increasing [Ca2+]i and DAG concentration, suggesting that the binding site of collagen type IV responsible for phospholipase C activation contains the RGD sequence. Together the present results suggest that, in pancreatic acinar cells, RGD sequence(s) within collagen type IV molecules cause activation of tyrosine kinase, probably through one of the integrin receptors, which then stimulates phospholipase C and increases [Ca2+]i.
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PMID:Collagen type IV stimulates an increase in intracellular Ca2+ in pancreatic acinar cells via activation of phospholipase C. 819 49

We have purified CR3 to homogeneity by affinity chromatography on C3bi-Sepharose and elution with EDTA. C3bi-coated erythrocytes bound to this purified CR3, and binding was dependent on the concentration of both C3bi and CR3, as well as on temperature and the presence of divalent cations. Moreover, binding could be blocked by mAb against CR3 or C3bi and could be enhanced by the addition of integrin modulating factor-1. We used the purified CR3 to test whether several putative ligands of CR3 directly bound the receptor. The interaction of purified CR3 with fibrinogen, filamentous hemagglutinin of Bordetella pertussis, lipophosphoglycan and glycoprotein 63 of Leishmania mexicana, and lipopolysaccharide from Escherichia coli was confirmed. However the interaction of CR3 with zymosan or its major component, beta-glucan, was not observed in these assays. Previous studies showed that binding of C3bi to PMN could be blocked with Arg-Gly-Asp (RGD) containing peptides and were interpreted to indicate that the RGD sequence in C3bi interacts directly with CR3. We found, however, that RGD containing peptides were unable to block the interaction of C3bi with purified CR3, yet retained the ability to block binding of C3bi to cells. We conclude that RGD-peptides do not directly bind CR3, but instead indirectly effect CR3 function. Inasmuch as the effect of RGD-peptides could be mimicked with antibodies against leukocyte response integrin, we suggest that RGD-peptides may bind to leukocyte response integrin on polymorphonuclear leukocytes and influence CR3 activity via this receptor.
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PMID:Ligand specificity of purified complement receptor type three (CD11b/CD18, alpha m beta 2, Mac-1). Indirect effects of an Arg-Gly-Asp (RGD) sequence. 837 80

Stimulation of monoblastic U937 cells with transforming growth factor beta 1 and 1,25-(OH)2 vitamin D3 (TGF-beta 1/D3) upregulates urokinase receptor (uPAR) and confers urokinase-dependent adhesiveness to the cells for serum- or vitronectin-coated surfaces. Recent studies show that uPAR itself is a high-affinity adhesion receptor for vitronectin and that urokinase (uPA) is an activator of this adhesive function. In the course of exploring possible G-protein involvement in this adhesion it was observed that TGF-beta 1/D3-primed U937 cells became adhesive to vitronectin in an uPAR-dependent manner when exposed to pertussis toxin (PTX). The adherent response is concentration- and time-dependent, and was not due to the ADP-ribosyltransferase activity of the toxin because the purified B-subunit of PTX was equally effective. Although promoting adhesion to serum- or vitronectin-coated surfaces, PTX blocked spontaneous cell adhesion to fibrinogen, an endogenous ligand for the Mac-1 receptor (CD11b/CD18). Flow cytometry study showed that expression of the alpha-subunit of Mac-1 (CD11b) on primed cells was increased by nearly threefold. Monoclonal antibody to CD11b abolished the PTX-induced cell adhesion and the binding of the primed cells to PTX-coated plates. Activation of Mac-1 receptor by its endogenous ligand fibrinogen induced cell adherent response similar to PTX. PTX, but not uPA, triggered a rapid rise in [Ca2+]i in primed U937 cells, and PTX-induced adhesion was significantly attenuated by 1,2-bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxy-methyl ester (BAPTA/AM), a selective membrane-permeant [Ca2+]i chelator. PTX-induced cell adhesion was also prevented by antibodies to uPAR and by conditioned medium containing soluble uPAR. Together these data indicate that PTX B-subunit may bind to Mac-1 integrin, which leads to a rapid rise in [Ca2+]i and subsequent activation of uPAR for adherence to vitronectin, suggesting a functional link between Mac-1 and activation of uPAR important to cellular trafficking and host defence in response to Bordetella pertussis infection.
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PMID:Mechanisms of pertussis toxin-induced myelomonocytic cell adhesion: role of Mac-1(CD11b/CD18) and urokinase receptor (CD87). 870 56

Integrin-associated protein (IAP or CD47) is a receptor for the cell/platelet-binding domain (CBD) of thrombospondin-1 (TS1), the most abundant protein of platelet alpha granules. Although it associates with alphaIIbbeta3, IAP has no known function in platelets. TS1, the CBD, and an IAP agonist peptide (4N1K) from the CBD of TS1 activate the platelet integrin alphaIIbbeta3, resulting in platelet spreading on immobilized fibrinogen, stimulation of platelet aggregation, and enhanced tyrosine phosphorylation of focal adhesion kinase. Furthermore, 4N1K peptide selectively stimulates the phosphorylation of LYN and SYK and their association with FAK. The phosphorylation of SYK is blocked by pertussis toxin, implicating a Gi-like heterotrimeric G protein. IAP solublized from membranes of unstimulated platelets binds specifically to an affinity column of 4N1K peptide. Both alphaIIb and beta3 integrin subunits and c-Src bind along with IAP. This complex of proteins is also detected with immunoprecipitation. Activation of platelets with the agonist peptide 4N1K results in the association of FAK with the IAP-alphaIIbbeta3 complex. Thus an important function of TS1 in platelets is that of a secreted costimulator of alphaIIbbeta3 whose unique properties result in its localization to the platelet surface and the fibrin clot.
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PMID:Thrombspondin acts via integrin-associated protein to activate the platelet integrin alphaIIbbeta3. 916 39

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