Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Type IV collagen (Coll IV), a component of the extracellular matrix, stimulates motility in the A2058 human melanoma cell line, a response that is inhibited by pertussis toxin (PT). Fibronectin (FN)-induced chemotaxis in this cell line is not affected by PT. To understand the mechanism of cellular signaling, single cell intracellular Ca2+ responses to Coll IV and FN were studied using Fura-2 and digital imaging fluorescence microscopy. Coll IV, at a dose that stimulates motility (100 micrograms/ml, 185 nM), induces a significant rise in cytosolic free Ca2+ concentration ([Ca2+]i) within 100 s. This response is not inhibited by PT. Treatment of the cells with FN 30 micrograms/ml (70 nM), a dose that stimulates near-maximal chemotaxis, does not increase [Ca2+]i appreciably. Removal of extracellular Ca2+ fails to inhibit the Coll IV-stimulated rise in Ca2+ in all cells. Depletion of extracellular Ca2+ and pretreatment of cells with Ca2+ channel blockers only partially inhibits Coll IV-induced motility. Depletion of intracellular Ca2+ inhibits both chemotaxis and the Coll IV-induced increase in intracellular Ca2+. Coll IV does not stimulate membrane phosphoinositide hydrolysis. We conclude that Coll IV treatment induces an inositol 1,4,5-trisphosphate-independent release of intracellular Ca2+ stores which appears to play a necessary role in the chemotactic response of A2058 cells but is not mediated by a PT-sensitive G-protein. This response is not seen in cells exposed to FN, suggesting different intracellular signaling mechanisms for stimulated motility between these two extracellular matrix molecules.
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PMID:Type IV collagen stimulates an increase in intracellular calcium. Potential role in tumor cell motility. 132 49

Migration of medial smooth muscle cells (SMC) into the intima is important in intimal thickening of atherosclerotic tissues. To study the functions of three isoforms of platelet-derived growth factor (PDGF) in atherosclerosis, we investigated their effects on SMC migration by Boyden's chamber method. Although PDGF-AB and PDGF-BB enhanced SMC migration dose-dependently, PDGF-AA did not enhance SMC migration, but instead inhibited SMC migration induced by PDGF-AB or PDGF-BB. PDGF-AA also inhibited SMC migration induced by two other migration factors, fibronectin and SMC-derived migration factor. PDGF-AA is considered to be coexpressed with transforming growth factor (TGF)-beta 1 in atherosclerotic tissues. Treatment of SMC with TGF-beta 1 reduced an autocrine migration activity from SMC. Studies using anti-PDGF antibody revealed that an increased secretion of PDGF-AA by TGF-beta 1 caused the reduced migration activity. cAMP increase by forskolin and dibutyryl cAMP suppressed SMC migration, whereas cAMP decrease by pertussis toxin had no effects on PDGF-AA-suppressed migration. In contrast, staurosporine, an inhibitor of protein kinase C, enhanced SMC migration and neutralized the inhibitory effect of PDGF-AA. These findings suggest that PDGF-AA regulates SMC migration in intimal thickening in atheroma formation and that protein kinase C may play an important role in the inhibitory mechanism of PDGF-AA.
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PMID:Regulatory effects of platelet-derived growth factor-AA homodimer on migration of vascular smooth muscle cells. 133 Oct 68

Human neutrophils adherent to a polystyrene plastic surface are vigorously activated, whereas those adherent to fibronectin manifest only a priming response. The basis of these metabolic differences was further characterized; polystyrene-adherent cells, which were shown to spread quickly upon adhesion, exhibited an increase of cytoskeleton-associated actin (F-actin) (measured by a nitrobenzoxadiazole-phallacidin fluorescent staining assay) and a decrease of monomeric G-actin concentration (measured by a DNase inhibition assay); in contrast, fibronectin-adherent cells exhibited little spreading and decreased their F-actin, after 1.5 min of adhesion, to 33.49 +/- 6.9% (mean +/- SD, n = 5) of initial levels found in suspended cells before plating. Actin depolymerization in fibronectin-adherent cells was confirmed by measuring G-actin, which sharply increased during the first minute of adhesion, rising from 0.065 +/- 0.007 to 0.20 +/- 0.035 microgram/microgram of protein (mean +/- SEM, p less than 0.05), and then remained elevated during 5 min of observation. In contrast, soluble fibronectin induced a decrease of G-actin in suspended cells. Cells pretreated with 1 microM cytochalasin D and allowed to adhere to a plastic surface did not spread, failed to generate O2-, and exhibited elevated concentrations of G-actin (0.1 to 0.2 microgram/microgram of protein) during the 5 min of observation. Actin changes, as well as respiratory burst, in adherent cells were shown to proceed through a pertussis toxin-insensitive pathway. Fluo-3 measurements of intracellular Ca2+ concentrations ([Ca2+]i) showed a fourfold and twofold [Ca2+]i increase in polystyrene- and fibronectin-adherent cells, respectively, after 2 min. The small rise in [Ca2+]i in fibronectin-adherent cells corresponds to a primed response of these cells to subsequent activation with FMLP. Ionomycin (1 microM) added to neutrophils just before adhesion on fibronectin induced full activation, i.e., O2- production and actin polymerization. The metabolic events controlling metabolic priming and actin depolymerization are as yet uncharacterized, but fibronectin receptor-linked responses beyond the mediation of cell adhesion have now been identified, suggesting complex metabolic functions of integrin receptors.
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PMID:Comparison of actin changes and calcium metabolism in plastic- and fibronectin-adherent human neutrophils. 150 Jul 23

Filamentous hemagglutinin (FHA), a 220-kDa protein that mediates the adhesion of Bordetella pertussis to eukaryotic cells, is a component of acellular vaccines against whooping cough. To identify the subregions of FHA that are immunogenic for T cells, 16 human T-cell clones were raised against purified FHA and tested for the recognition of recombinant and proteolytic fragments. The clones were found to map either in the carboxy-terminal or the amino-terminal part of the FHA molecule, but none of them recognized the central region, which contains a sequence that is homologous to that of the eukaryotic protein fibronectin. These data suggest that subregions of FHA that do not contain sequences that are potentially cross-reactive with self proteins may be sufficient to induce an immune response against the whole protein.
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PMID:Identification of subregions of Bordetella pertussis filamentous hemagglutinin that stimulate human T-cell responses. 171 27

3H-Labelled kappa-elastin peptides (kE:75 kDa molecular weight) were shown to bind to confluent human skin fibroblast (HSF) cultures in a time-dependent and saturable manner. Scatchard analysis indicated the presence of high affinity binding sites with kD = 2.7 x 10(-10) M and 19,000 sites per cell. Binding of kE to its receptor on HSF accelerates and intensifies the adhesion of insoluble elastin fibres (iE) to confluent HSF. Optimal effect was attained for a kE concentration of 0.3 x 10(-9) M close to kD. This stimulatory effect of kE on the binding of iE to HSF could be inhibited by neomycin, retinal and pertussis toxin, substances which act at different levels of the transduction mechanism following the activation of the receptor and the subsequent triggering of cell biological events (chemotaxis, modification of calcium fluxes). The stimulation of iE adhesion to HSF induced by kE as well as kE binding to the cells could be inhibited by lactose and laminin but not by Arg-Gly-Asp-Ser(RGDS) peptides. This indicates that the elastin peptide receptor on HSF possesses lectin-like properties and shares homology with the laminin receptor as also shown for other cell types. None of the substances tested, that is inhibitors of the transduction mechanism, lactose, laminin and Arg-Gly-Asp-Ser(RGDS) peptides were shown to interfere significantly with the binding of iE (in the absence of added kE) to confluent HSF. The proteins adhering strongly to elastin fibres were isolated by a sequential extraction procedure and the final hydrochloride guanidinium-DTT extract was analysed by SDS-PAGE under reducing conditions, Western blots using specific antibodies against several connective tissue proteins and affinity for [3H]-kE following nitrocellulose electro-transfer of proteins. Fibronectin, vitronectin, tropoelastin(s), and a 120 kDa cysteine rich glycoprotein previously designated as elastonectin were identified. Among these proteins, [3H]-kE was found to bind exclusively to a 65 kDa protein that could be eluted selectively from elastin fibres with a neutral buffer containing 100 mM lactose. Therefore the elastin peptide receptor on human skin fibroblasts shares properties with the elastin receptor characterized from other cell types. Conformational differences between elastin peptides and elastin fibres could explain the differences in the mechanisms of interactions between elastin fibres and elastin peptides with HSF in culture. The stimulatory effect of elastin-derived peptides on the adhesion of elastin fibres to HSF could have implications in the oriented biosynthesis of elastin fibres.
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PMID:Mechanisms of interaction between human skin fibroblasts and elastin: differences between elastin fibres and derived peptides. 172 59

On the surface of phagocytes, C3b receptors (CR1) bind C3b-coated particles and promote their ingestion after activation by appropriate stimuli such as lymphokines or the chemoattractant formyl methionyl leucyl phenylalanine (fMLP) and fibronectin. The aims of the present study were 1) to define at the electron microscopic level the nature of the process responsible for CR1 internalization and 2) to dissect the mechanism by which a physiological activator (fMLP) stimulates this process. CR1 was visualized either by the immunogold technique or by quantitative electron microscopic autoradiography using a monoclonal anti-CR1 antibody. Both techniques revealed that after anti-CR1 binding, CR1 cluster on the neutrophil surface in a time-, temperature-, and antibody-dependent fashion, but do not concentrate in coated pits. CR1 internalization requires receptor cross-linking (does not occur in the presence of Fab fragments of anti-CR1) and intact microfilaments. It results in the association of the internalized material with large flattened vacuoles, organized in stacks. Together with the surface localization of CR1 close to cytoplasmic projections (ruffles), these observations suggest that uptake of CR1 occurs through a macropinocytotic process. Eventually, CR1 concentrate in lysosomal structures. fMLP markedly stimulates this pattern of CR1 internalization without affecting their clustering or their lack of association with coated pits. Stimulation by fMLP is inhibited by pertussis toxin, unaffected by preventing receptor-triggered cytosolic free calcium [Ca2+]i elevations, and mimicked by phorbol myristate acetate. Taken together our data demonstrate 1) that, in neutrophils, CR1 is internalized via a coated pit independent macropinocytotic process, dependent on intact microfilaments and receptor cross-linking; 2) that, in the same cells, fMLP is internalized via the classical coated pits pathway; and 3) that fMLP amplifies CR1 uptake possibly via protein kinase C stimulation.
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PMID:Internalization pathway of C3b receptors in human neutrophils and its transmodulation by chemoattractant receptors stimulation. 182 92

Membranes from 2 K1735 murine melanoma clones of high invasive capacity show increased amounts of pertussis toxin (PT) substrate when compared to a weakly invasive cellular counterpart. Using a panel of specific G-protein antibodies, we identified Gi alpha 2 as the PT-sensitive G-protein uniquely abundant in highly invasive cells. In addition, RNA hybridization results confirm the immunoblot observations that Gi alpha 2 is present at higher levels in strongly invasive cells. This result suggests that the elevated expression of Gi alpha 2 in highly invasive cells is not entirely due to differences in either translational efficiency or protein degradation but is related to altered RNA transcriptional initiation, processing and/or degradation. ADP-ribosylation of Gi alpha-subunits by PT inhibited the fibronectin, laminin and collagen type-IV-stimulated motility of the 2 highly invasive clones, while PT treatment of cells from a poorly invasive clone resulted in little or no reduction of the fibronectin, laminin or collagen type-IV-stimulated lower motility. Furthermore, PT treatment of highly or poorly invasive K1735 clones does not result in any alteration in cellular cAMP accumulation, suggesting that the PT substrate is not linked with the adenylyl cyclase enzyme complex. The data suggest that a PT-sensitive G-protein, probably Gi alpha 2 regulates second messenger pathways that contribute to elevated motility in highly invasive K1735 cells.
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PMID:The role of G-protein in matrix-mediated motility of highly and poorly invasive melanoma cells. 185 Mar 81

The effect of pertussis toxin (PT) on transforming growth factor beta 1 (TGF beta 1)-induced proto-oncogene expression was investigated in AKR-2B fibroblasts. PT substantially abolished c-sis and c-myc mRNA expression following TGF beta 1 stimulation. This inhibitory effect was specific for TGF beta 1-stimulated proto-oncogene expression and associated with the ADP-ribosylation of a 41-kDa substrate. Actinomycin D decay and nuclear run-on experiments demonstrated that the inhibitory effects of PT are a result of decreased transcriptional activation and not to an increased decay of proto-oncogene message. PT did not, however, affect TGF beta 1-stimulated fibronectin and collagen mRNA accumulation nor did it have any inhibitory effect on TGF beta 1-induced morphological transformation. These data indicate that TGF beta 1-stimulated gene expression is coupled to multiple pathways distinguished by their sensitivity to PT.
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PMID:Distinct pathways regulate transforming growth factor beta 1-stimulated proto-oncogene and extracellular matrix gene expression. 215 88

Transduction of signals initiating motility by extracellular matrix (ECM) molecules differed depending on the type of matrix molecule and whether the ligand was in solution or bound to a substratum. Laminin, fibronectin, and type IV collagen stimulated both chemotaxis and haptotaxis of the A2058 human melanoma cell line. Peak chemotactic responses were reached at 50-200 nM for laminin, 50-100 nM for fibronectin, and 200-370 nM for type IV collagen. Checkerboard analysis of each attractant in solution demonstrated a predominantly directional (chemotactic) response, with a minor chemokinetic component. The cells also migrated in a concentration-dependent manner to insoluble step gradients of substratum-bound attractant (haptotaxis). The haptotactic responses reached maximal levels at coating concentrations of 20 nM for laminin and type IV collagen, and from 30 to 45 nM for fibronectin. Pretreatment of cells with the protein synthesis inhibitor, cycloheximide (5 micrograms/ml), resulted in a 5-30% inhibition of both chemotactic and haptotactic responses to each matrix protein, indicating that de novo protein synthesis was not required for a significant motility response. Pretreatment of cells with 50-500 micrograms/ml of synthetic peptides containing the fibronectin cell-recognition sequence GRGDS resulted in a concentration-dependent inhibition of fibronectin-mediated chemotaxis and haptotaxis (70-80% inhibition compared to control motility); negative control peptide GRGES had only a minimal effect. Neither GRGDS nor GRGES significantly inhibited motility to laminin or type IV collagen. Therefore, these results support a role for the RGD-directed integrin receptor in both types of motility response to fibronectin. After pretreatment with pertussis toxin (PT), chemotactic responses to laminin, fibronectin, and type IV collagen were distinctly different. Chemotaxis to laminin was intermediate in sensitivity; chemotaxis to fibronectin was completely insensitive; and chemotaxis to type IV collagen was profoundly inhibited by PT. In marked contrast to the inhibition of chemotaxis, the hepatotactic responses to all three ligands were unaffected by any of the tested concentrations of PT. High concentrations of cholera toxin (CT; 10 micrograms/ml) or the cAMP analogue, 8-Br-cAMP (0.5 mM), did not significantly affect chemotactic or haptotactic motility to any of the attractant proteins, ruling out the involvement of cAMP in the biochemical pathway initiating motility in these cells. The sensitivity of chemotaxis induced by laminin and type IV collagen, but not fibronectin, to PT indicates the involvement of a PT-sensitive G protein in transduction of the signals initiating motility to soluble laminin and type IV collagen.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Signal transduction for chemotaxis and haptotaxis by matrix molecules in tumor cells. 232

Membranes from a B16 murine melanoma clone of high experimental metastatic capacity show increased amounts of pertussis toxin (PT) substrate when compared to a low metastatic counterpart. Using specific antibodies, we identified Gi2 as the PT-sensitive G-protein uniquely abundant in highly metastatic cells. ADP ribosylation of a G-protein alpha subunit by PT decreased both the migration of tumor cells through Matrigel (Collaborative Research, Bedford, MA) and the fibronectin-, laminin-, and collagen type IV-mediated motility of a high metastatic clone. Treatment of cells from a low metastatic clone with PT did not alter either the relatively low invasive capacity or lower motility of these cells. While cholera toxin treatment of cells resulted in decreased invasion and motility of both high and low metastatic clones, there were significant qualitative and quantitative differences, when compared to the PT effects, which indicated that the two toxins were acting on different second messenger systems. PT treatment of B16 clones of high or low experimental metastatic capacity does not result in any alteration in cellular cyclic AMP accumulation suggesting that the PT substrate is not linked with the adenylyl cyclase enzyme complex. The data suggest that a PT-sensitive G-protein, possibly Gi2, regulates second messenger pathways that contribute to the metastatic capacity of B16 melanoma cells.
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PMID:G-protein involvement in matrix-mediated motility and invasion of high and low experimental metastatic B16 melanoma clones. 247 50


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