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Query: UMLS:C0043167 (
pertussis
)
19,595
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
A number of factors have been shown to influence osteoblastic proliferation, including fluoride. Recent observations suggest that heterotrimeric G proteins are probably involved in the mitogenic response induced by this agent, further suggesting a role of guanosine 5'-triphosphate (GTP)-binding protein-coupled receptors (GPCR) in the regulation of osteoblastic cell growth. We therefore explored what mitogenic factors known to activate GPCR can influence the replication of mouse osteoblast-like MC3T3-E1 cells. Among several candidates, epinephrine was found to be a potent mitogen for these cells, and its effect on the growth and differentiation of these cells was further investigated. Deoxyribonucleic acid (DNA) synthesis was dose dependently enhanced by this catecholamine in the concentration range of 1 nmol/L-10 micromol/L. Stimulation of DNA synthesis by catecholamines was in the order of epinephrine > norepinephrine >> isoproterenol, indicating that alpha adrenergic receptors mediated this cellular response. Further analysis with specific adrenergic receptor agonists and antagonists suggested that the mitogenic response induced by epinephrine in MC3T3-E1 cells is mediated by alpha1 adrenergic receptors. In addition to its effect on cell replication, epinephrine also enhanced alkaline phosphatase (ALP) activity in these cells but had little effect on
collagen
synthesis and osteocalcin production. As for the mitogenic response, the change in ALP activity was found to be mediated by alpha1 adrenergic receptors. Both effects of epinephrine on cell replication and ALP activity were markedly reduced by pretreatment of the cells with
pertussis
toxin (PTX), suggesting a role of Gi proteins. These effects were also completely blocked by pretreatment of the cells with 50 micromol/L genistein, a nonselective inhibitor of tyrosine kinase. In conclusion, the results indicate that epinephrine enhances replication and ALP activity of MC3T3-E1 osteoblast-like cells via alpha1 adrenergic receptors coupled to Gi proteins. The signaling mechanism probably involves a tyrosine phosphorylation mechanism. These observations suggest that PTX-sensitive G proteins are potent mediators of cell proliferation and ALP activity of osteoblast-like cells in response to factors acting through G protein-coupled receptors.
...
PMID:Catecholamines stimulate the proliferation and alkaline phosphatase activity of MC3T3-E1 osteoblast-like cells. 973 41
To learn more about the regulation of contraction of
collagen
matrices by fibroblasts, we compared the ability of lysophosphatidic acid (LPA) and platelet-derived growth factor (PDGF) to stimulate contraction of floating and stressed
collagen
matrices. In floating
collagen
matrices, PDGF and LPA stimulated contraction with similar kinetics, but appeared to utilize complementary signaling pathways since contraction obtained by the combination of growth factors exceeded that observed with saturating concentrations of either alone. The PDGF-simulated pathway was selectively inhibited by the protein kinase inhibitor KT5926. In stressed
collagen
matrices, PDGF and LPA stimulated contraction with different kinetics, with LPA acting rapidly and PDGF acting only after an approximately 1-h lag period.
Pertussis
toxin, known to block signaling through the Gi class of heterotrimeric G-proteins, inhibited LPA-stimulated contraction of floating but not stressed matrices, suggesting that LPA-stimulated contraction depends on receptors coupled to different G-proteins in floating and stressed matrices. On the other hand, the Rho inhibitor C3 exotransferase blocked contraction of both floating and stressed
collagen
matrices. These results suggest the possibility that distinct signaling mechanisms regulate contraction of floating and stressed
collagen
matrices.
...
PMID:Differences in the regulation of fibroblast contraction of floating versus stressed collagen matrices. 987 32
In extravasation of T cells, little is known about the mechanisms of transendothelial migration subsequent to the T cells' tight adhesion to endothelium. To investigate these mechanisms, we developed a monoclonal antibody (mAb), termed anti-4C8, that blocks transmigration but not adhesion in a culture system in which high CD26-expressing (CD26(hi)) T cells preferentially migrate through human umbilical vein endothelial cell (HUVEC) monolayers cultured on
collagen
gels. Anti-4C8 reacted with all CD3(+) T cells and monocytes but not neutrophils or HUVECs. The structure defined by this antibody was an 80-kD molecule. The mAb at 1 mug/ml inhibited 80-90% of migration of CD3(+) T cells through unstimulated and interferon gamma-stimulated HUVEC monolayers without interfering with adhesion and cell motility. When added to the cultures after the adhesion, anti-4C8 completely blocked subsequent transmigration of adherent T cells. Phase-contrast and electron microscopy revealed that T cells are arrested at the intercellular junctions of HUVECs in the presence of anti-4C8. Anti-4C8 exhibited agonistic effects on resting T cells without other stimuli under culture conditions in which anti-4C8 can stimulate T cells. First, in the checkerboard assay using
collagen
gels, the antibody promoted chemokinetic migration of the cells in a dose-dependent manner from 0.1 to 10 mug/ml. The predominant population of T cells that migrated into
collagen
gels with impregnated anti-4C8 were CD26(hi). Second, solid-phase-immobilized anti-4C8 induced adhesion of T cells to the substrate, often with polarizations in cell shape and large pseudopods rich in filamentous (F-) actin. Third, soluble anti-4C8 augmented F-actin content preferentially in CD26(hi) T cells when added to T cells at a high dose of 10 mug/ml. Finally, both anti-4C8-induced chemokinetic migration and transendothelial migration were inhibited by pretreatment of T cells with
pertussis
toxin. These findings suggest that stimulation via the 4C8 antigen increases cell motility of CD26(hi) cells with profound cytoskeletal changes through signaling pathways including G proteins. The 4C8 antigen may be involved in preferential transmigration of CD26(hi) cells adherent to HUVECs.
...
PMID:Characterization of the 4C8 antigen involved in transendothelial migration of CD26(hi) T cells after tight adhesion to human umbilical vein endothelial cell monolayers. 1007 81
Integrin-associated protein (IAP/CD47) augments the function of alpha2beta1 integrin in smooth muscle cells (SMC), resulting in enhanced chemotaxis toward soluble
collagen
(Wang, X-Q., and W.A. Frazier. 1998. Mol. Biol. Cell. 9:865). IAP-deficient SMC derived from IAP(-/-) animals did not migrate in response to 4N1K (KRFYVVMWKK), a peptide agonist of IAP derived from the COOH-terminal domain of thrombospondin-1 (TSP1). When normal SMC were preincubated with 4N1K or an anti-alpha2beta1 function-stimulating antibody, cell migration to soluble
collagen
was significantly enhanced. 4N1K-induced chemotaxis was blocked by treatment of SMC with
pertussis
toxin indicating that IAP acts through Gi. In agreement with this, 4N1K evoked a rapid decrease in cAMP levels which was intensified in the presence of
collagen
, and forskolin and 8-Br-cAMP both inhibited SMC migration stimulated via IAP. 4N1K strongly inhibited extracellular regulated kinase (ERK) activation in SMC attaching to
collagen
and reduced basal ERK activity in suspended SMC.
Pertussis
toxin treatment of SMC significantly activated ERK, suggesting that an inhibitory input was alleviated. Inhibition of ERK activity by (a) the MAP kinase kinase (MEK) inhibitor, PD98059, (b) antisense oligonucleotide depletion of ERK, and (c) expression of mitogen-activated protein (MAP) kinase phosphatase-1 in SMC all led to increased migration to
collagen
, 4N1K, or 4N1K plus
collagen
. Thus, IAP stimulates alpha2beta1 integrin-mediated SMC migration via Gi-mediated inhibition of ERK activity and suppression of cyclic AMP levels. Both of these signaling pathways could directly modulate the state of the integrin as well as impact downstream components of the cell motility apparatus.
...
PMID:Integrin-associated protein stimulates alpha2beta1-dependent chemotaxis via Gi-mediated inhibition of adenylate cyclase and extracellular-regulated kinases. 1052 43
Sphingosine 1-phosphate (SPP) has been shown to inhibit chemotaxis of a variety of cells, in some cases through intracellular actions, while in others through receptor-mediated effects. Surprisingly, we found that low concentrations of SPP (10-100 nM) increased chemotaxis of HEK293 cells overexpressing the G protein-coupled SPP receptor EDG-1. In agreement with previous findings in human breast cancer cells (Wang, F., Nohara, K., Olivera, O., Thompson, E. W., and Spiegel, S. (1999) Exp. Cell Res. 247, 17-28), SPP, at micromolar concentrations, inhibited chemotaxis of both vector- and EDG-1-overexpressing HEK293 cells. Nanomolar concentrations of SPP also induced a marked increase in chemotaxis of human umbilical vein endothelial cells (HUVEC) and bovine aortic endothelial cells (BAEC), which express the SPP receptors EDG-1 and EDG-3, while higher concentrations of SPP were less effective. Treatment with
pertussis
toxin, which ADP-ribosylates and inactivates G(i)-coupled receptors, blocked SPP-induced chemotaxis. Checkerboard analysis indicated that SPP stimulates both chemotaxis and chemokinesis. Taken together, these data suggest that SPP stimulates cell migration by binding to EDG-1. Similar to SPP, sphinganine 1-phosphate (dihydro-SPP), which also binds to this family of SPP receptors, enhanced chemotaxis; whereas, another structurally related lysophospholipid, lysophosphatidic acid, did not compete with SPP for binding nor did it have significant effects on chemotaxis of endothelial cells. Furthermore, SPP increased proliferation of HUVEC and BAEC in a
pertussis
toxin-sensitive manner. SPP and dihydro-SPP also stimulated tube formation of BAEC grown on
collagen
gels (in vitro angiogenesis), and potentiated tube formation induced by basic fibroblast growth factor.
Pertussis
toxin treatment blocked SPP-, but not bFGF-stimulated in vitro angiogenesis. Our results suggest that SPP may play a role in angiogenesis through binding to endothelial cell G(i)-coupled SPP receptors.
...
PMID:Sphingosine 1-phosphate stimulates cell migration through a G(i)-coupled cell surface receptor. Potential involvement in angiogenesis. 1058 1
Trypsin is widely expressed in various non-pancreatic tissues at low levels and overexpressed in some types of human cancers. In the present study, we found that trypsin stimulates integrin-dependent adhesion and growth of MKN-1 human gastric carcinoma cells. MKN-1 cells expressed both proteinase-activated receptor-1 (PAR-1) and PAR-2, which are activated by thrombin and trypsin, respectively. Both trypsin and the PAR-2 ligand SLIGKV promoted integrin alpha(5)beta(1)-mediated adhesion of MKN-1 cells to fibronectin, and less effectively integrin alpha(v)beta(3)-mediated cell adhesion to vitronectin, but not that to type IV
collagen
or laminin-1 at all. Thrombin and the PAR-1 ligand SFLLRN promoted the cell adhesion to vitronectin more strongly than trypsin or the PAR-2 ligand, but not the cell adhesion to fibronectin at all. The cell adhesion-stimulating effect of the PAR-2 ligand was significantly reduced by the pre-treatment of cells with trypsin, indicating that the effect of trypsin is mediated by PAR-2 activation. The trypsin-stimulated cell adhesion to vitronectin, but not to fibronectin, was effectively inhibited by the G(i) protein blocker
pertussis
toxin, and both cell adhesions were completely inhibited by the Src kinase inhibitor herbimycin A. Furthermore, trypsin and the PAR-2 ligand stimulated growth of MKN-1 cells more strongly than thrombin or the PAR-1 ligand. These results show that trypsin regulates cellular adhesion and proliferation by inducing PAR-2/G protein signalings, and that the integrin alpha(5)beta(1)- and integrin alpha(v)beta(3)-dependent cell adhesions are regulated by different PAR/G protein signalings.
...
PMID:Trypsin stimulates integrin alpha(5)beta(1)-dependent adhesion to fibronectin and proliferation of human gastric carcinoma cells through activation of proteinase-activated receptor-2. 1067 85
Sphingosylphosphorylcholine (SPC), a sphingolipid metabolite, has recently been reported to stimulate wound healing in an animal model. To clarify the mechanism of SPC on the healing process, we examined the effect of SPC on wound contraction using an in vitro model. A mixture of human dermal fibroblasts and porcine type I collagen in a serum-free medium was gelled, and then separated from the well after a 12-h incubation. Various reagents were applied to the medium, and its contractile activity was analysed by measuring the amount of contracted surface area. Among the sphingolipid metabolites, SPC and sphingosine-1-phosphate, but not sphingosine, C2-ceramide and C6-ceramide, stimulated
collagen
gel contraction. Maximal gel contraction, observed at 10 micromol L-1 of SPC, occurred as early as 1 h after the treatment and persisted for more than 48 h. The effect of SPC was not inhibited by pretreatment with antitransforming growth factor-beta or antiplatelet-derived growth factor-BB antibodies. Among the various signal transduction inhibitors,
pertussis
toxin, staurosporine and H7 were found to inhibit the action of SPC, whereas genistein and tyrphostin A47 were not, suggesting that fibroblast contraction induced by SPC is mediated by a trimeric guanosine triphosphate-binding protein (G protein)-coupled receptor and protein kinase. Our findings imply that the effect of SPC as a healing stimulant might be due in part to stimulation of fibroblast contraction in granulation tissue.
...
PMID:Sphingosylphosphorylcholine stimulates contraction of fibroblast-embedded collagen gel. 1088 37
Sphingosine 1-phosphate (S-1-P), a lipid mediator shown to be a ligand for aortic G protein-coupled receptor [corrected] (AGRs), endothelial differentiation gene (EDG)1, EDG3, and AGR16/EDG5, is stored in platelets and released on their activation. Platelet consumption occurs in acute liver injury. Hepatic stellate cells (HSCs) play an important role in wound healing. Effects of S-1-P on HSCs were investigated. S-1-P enhanced proliferation of culture-activated HSCs. The mitogenic effect was
pertussis
toxin sensitive, mitogen-activated protein kinase dependent, and more prominent at lower cell density. S-1-P increased contraction of
collagen
lattices containing HSCs, irrespective of activation state, in a C3 exotoxin-sensitive manner. mRNAs of EDG1 and AGR16, but not of EDG3, were detected in HSCs. In HSC activation, EDG1 mRNA levels were downregulated, whereas AGR16 mRNA levels were unchanged. Considering that HSCs are capable of production of extracellular matrices and modulation of blood flow in sinusoids, our results suggest that S-1-P may play a role in wound healing process in the liver.
...
PMID:Biological activities of novel lipid mediator sphingosine 1-phosphate in rat hepatic stellate cells. 1091 38
During the second phase of osteogenesis in vitro, rat osteoblasts secrete inducer(s) of chemotaxis and chemoinvasion of endothelial and tumor cells. We report here the characterization and purification from mature osteoblast conditioned medium of the agent chemotactic for endothelial cells. The chemoactive conditioned medium specifically induces directional migration of endothelial cells, not affecting the expression and activation of gelatinases, cell proliferation, and scattering. Directional migration induced in endothelial cells by conditioned medium from osteoblasts is inhibited by
pertussis
toxin, by blocking antibodies to integrins alpha(1), beta(1), and beta(3), and by antibodies to metalloproteinase 2 and 9. The biologically active purified protein has two sequences, coincident with the amino-terminal amino acids, respectively, of the alpha(1) and of the alpha(2) carboxyl propeptides of type I collagen, as physiologically produced by procollagen C proteinase. Antibodies to type I collagen and to the carboxyl terminus of alpha(1) or alpha(2) chains inhibit chemotaxis. The chemoattractant is the propeptide trimer carboxyl-terminal to type I collagen, and its activity is lost upon reduction. These data illustrate a previously unknown function for the carboxyl-terminal trimer, possibly relevant in promoting endothelial cell migration and vascularization of tissues producing
collagen
type I.
...
PMID:Trimer carboxyl propeptide of collagen I produced by mature osteoblasts is chemotactic for endothelial cells. 1092
We have pioneered an in vitro pseudopod-generation model wherein suspended tumor cells are stimulated to form pseudopods into glass micropipettes in response to soluble
collagen
type IV (CIV).
Pertussis
toxin and removing intracellular calcium were found previously to be inhibitory to that process. We now extend those observations to dissect the roles of transmembrane calcium influx and circulating fatty acids on pseudopod extension. Removal of fatty acids from BSA in basal media resulted in abrogation of pseudopod formation, while reconstitution of free fatty acids restored cell pseudopod protrusion. We thus hypothesized that fatty acids may provide necessary pseudopod stimulatory signals. Addition of lysophosphatidic acid (LPA) to the fatty acid-free CIV solution or in an opposite pipette without CIV permitted approximately 50% pseudopod recovery in all pipette directions in a dose-dependent fashion. Thapsigargin (TG), an agent that releases internal calcium stores and causes opening of store-operated calcium channels, restored pseudopod protrusion up to 80% in CIV with fatty acid-free albumin. [Ca(2+)](i) release was non-additive when cells were stimulated by TG and LPA, suggesting overlapping [Ca(2+)](i) stores. The combination of TG and LPA in fatty acid-free albumin fully restored the pseudopod response to CIV. Addition of EGTA to chelate stimulatory media calcium blocked the pseudopod response to CIV in the presence of fatty acids. This indicates that pseudopod protrusion requires transmembrane calcium entry. Thus, extracellular lipids and calcium mobilization are required to complement CIV in pseudopod protrusion from suspended cells.
...
PMID:Extracellular lipid-mediated signaling in tumor-cell activation and pseudopod protrusion. 1105 76
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