scholarly journals Monocyte chemoattractant protein 1 causes differential signalling mediated by proline-rich tyrosine kinase 2 in THP-1 cells

2001 ◽  
Vol 355 (3) ◽  
pp. 751-756 ◽  
Author(s):  
Masahide YAMASAKI ◽  
Hidenori ARAI ◽  
Noboru ASHIDA ◽  
Kenji ISHII ◽  
Toru KITA
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Signalling Pathways ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein ◽  
Tyrosine Kinase 2

Monocyte chemoattractant protein 1 (MCP-1) has a crucial role in atherogenesis and inflammation. However, MCP-1-mediated signalling pathways in monocytes have not been fully elucidated. In the present study we investigated the role of tyrosine kinases such as proline-rich tyrosine kinase 2 (Pyk2) in MCP-1-mediated signal transduction in the monocytic cell line THP-1. Pyk2 was tyrosine phosphorylated very quickly after stimulation with MCP-1. We found that Lyn, Shc and paxillin were also tyrosine phosphorylated by MCP-1. We examined the association of these molecules by immunoprecipitation and immunoblot analysis. The association of Pyk2 with Lyn was dependent on stimulation with MCP-1 and on tyrosine phosphorylation of Pyk2. Phosphorylation of p38 was also dependent on tyrosine phosphorylation of Pyk2. However, the association of Pyk2 with paxillin and Grb2 was not affected by stimulation with MCP-1. Phosphorylation of ERK (extracellular-signal-regulated protein kinase) was not affected by overexpression of kinase-negative Pyk2. Our results indicate that Pyk2 forms a complex with paxillin, Grb2 and Lyn in THP-1 cells. However, Pyk2 is not always involved in MCP-1-mediated signalling pathways.

Multimerization of monocyte chemoattractant protein-1 is not required for glycosaminoglycan-dependent transendothelial chemotaxis

2001 ◽  
Vol 358 (3) ◽  
pp. 737-745 ◽  
Author(s):  
Simi ALI ◽  
Adrian C. V. PALMER ◽  
Sarah J. FRITCHLEY ◽  
Yvonne MALEY ◽  
John A. KIRBY
Keyword(s):  
Cell Surface ◽  
Fusion Protein ◽  
Radioligand Binding ◽  
Heparan Sulphate ◽  
Placental Alkaline Phosphatase ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein

Chemokines interact with specific G-protein-coupled cell-surface receptors and with glycosaminoglycans (GAGs), such as heparan sulphate. Although chemokines often form multimers in solution, this process may be enhanced following interaction with GAGs on the cell surface, or within the extracellular matrix. However, the significance of multimerization for chemokine function remains controversial. In the present study, a fusion protein was prepared between the prototypical human CC chemokine, monocyte chemoattractant protein-1 (MCP-1; also known as CCL-2) and a large secreted placental alkaline phosphatase (SEAP) moiety. This fusion protein (MCP-1–SEAP) remained monomeric under conditions that promote oligomerization of the native chemokine. Radioligand binding showed that both native MCP-1 and MCP-1–SEAP competed for the same site on the surface of HEK-293 cells expressing the CCR2b chemokine receptor. The interaction between either chemokine species and endothelial cell surface GAGs was antagonized by the addition of the heparan sulphate-like molecule, heparin. Both MCP-1 and MCP-1–SEAP induced a Ca2+-flux in the THP-1 monocytic cell line, and were equally effective at promoting transendothelial chemotaxis of mononuclear immune cells, with maximal migration being produced by treatment with 12nM of either species. In each case this chemotactic response was almost completely antagonized by the addition of heparin. The importance of interaction between either native MCP-1 or MCP-1–SEAP and cell-surface GAGs for transcellular migration was demonstrated by the almost complete absence of leucocyte chemotaxis across monolayers of GAG-deficient mutant cells. In summary, this study shows that multimerization is neither necessary for, nor potentiates, the biological activity of MCP-1. However, the results do clearly demonstrate the importance of the interaction between MCP-1 and cell-surface heparan sulphate for transmonolayer leucocyte chemotaxis.

scholarly journals Altered Association of Protein Tyrosine Kinases with Postsynaptic Densities after Transient Cerebral Ischemia in the Rat Brain

2000 ◽  
Vol 20 (3) ◽  
pp. 505-512 ◽  
Author(s):  
Herman H. Cheung ◽  
Norio Takagi ◽  
Lucy Teves ◽  
Richard Logan ◽  
M. Christopher Wallace ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Nmda Receptor ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Transient Cerebral Ischemia ◽  
Protein Tyrosine Kinases ◽  
Vessel Occlusion ◽  
Protein Tyrosine ◽  
Tyrosine Kinase 2

Transient cerebral ischemia results in an increase in the tyrosine phosphorylation of proteins associated with postsynaptic densities (PSDs). The authors investigated the possible mechanisms behind this increase by analyzing isolated PSDs for protein tyrosine kinase activity and for the presence of specific tyrosine kinases. Transient (15 minutes) global ischemia was produced in adult rats by four-vessel occlusion, and PSDs were isolated immediately after ischemia or after 20 minutes or 6 hours of reperfusion. Tyrosine phosphorylation of several PSD proteins, including the N-methyl-d-aspartate (NMDA) receptor subunits NR2A and NR2B, was enhanced relative to shams after 20 minutes of reperfusion and underwent a further increase between 20 minutes and 6 hours. The ability of intrinsic PSD tyrosine kinase to phosphorylate PSD proteins, including the NMDA receptor, increased threefold after ischemia. Whereas PSD-associated proline-rich tyrosine kinase 2 (PYK2) and gp145TrkB were elevated immediately after the ischemic event, increases in Src and Fyn were not apparent until 6 hours of reperfusion. The level of PSD-associated pp125FAK decreased after ischemia. The results demonstrate that ischemia results in selective changes in the association of protein tyrosine kinases with the PSD which may account for ischemia-induced increases in the tyrosine phosphorylation of PSD proteins.

Homocysteine induces monocyte chemoattractant protein-1 expression by activating NF-κB in THP-1 macrophages

2001 ◽  
Vol 280 (6) ◽  
pp. H2840-H2847 ◽  
Author(s):  
Guoping Wang ◽  
Yaw L. Siow ◽  
Karmin O
Keyword(s):  
Underlying Mechanism ◽  
Inhibitory Protein ◽  
Monocytic Cell ◽  
Monocyte Chemoattractant Protein 1 ◽  
Arterial Walls ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein ◽  
Monocyte Migration ◽  
Human Monocytic Cell ◽  
Monocyte Chemotaxis

Homocysteinemia is an independent risk factor for cardiovascular disorders. The recruitment of monocytes is an important event in atherogenesis. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemokine that stimulates monocyte migration into the intima of arterial walls. The objective of the present study was to investigate the effect of homocysteine on MCP-1 expression in macrophages and the underlying mechanism of such effect. Human monocytic cell (THP-1)-derived macrophages were incubated with homocysteine. By nuclease protection assay and ELISA, homocysteine (0.05–0.2 mM) was shown to significantly enhance the expression of MCP-1 mRNA (up to 2.6-fold) and protein (up to 4.8-fold) in these cells. Homocysteine-induced MCP-1 expression resulted in increased monocyte chemotaxis. The increase in MCP-1 expression was associated with activation of nuclear factor (NF)-κB due to increased phosphorylation of the inhibitory protein (IκB-α) as well as reduced expression of IκB-α mRNA in homocysteine-treated cells. In conclusion, our results demonstrate that homocysteine, at pathological concentration, stimulates MCP-1 expression in THP-1 macrophages via NF-κB activation.

Proline-rich Tyrosine Kinase 2 and Focal Adhesion Kinase Are Involved in Different Phases of Platelet Activation by vWF

2002 ◽  
Vol 87 (03) ◽  
pp. 509-517 ◽  
Author(s):  
Ilaria Canobbio ◽  
Paolo Lova ◽  
Fabiola Sinigaglia ◽  
Cesare Balduini ◽  
Mauro Torti
Keyword(s):  
Tyrosine Kinase ◽  
Focal Adhesion Kinase ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Human Platelets ◽  
Glycoprotein Ib ◽  
Tyrosine Kinase 2 ◽  
Calcium Chelation ◽  
Stimulation Of

SummaryStimulation of human platelets with von Willebrand factor (vWF) induces the rapid tyrosine phosphorylation of several proteins, but very little is known on the tyrosine kinases involved in this process. In the present work, we investigated and compared the activation of two related tyrosine kinases expressed in platelets: the proline-rich tyrosine kinase 2 (Pyk2) and the focal adhesion kinase (FAK). Both kinases were tyrosine phosphorylated upon vWF interaction with glycoprotein Ib-IX-V complex, but with different mechanisms. Tyrosine phosphorylation of FAK was totally dependent on thromboxane A2 production, and was inhibited by the integrin αIIbβ3 antagonist RGDS peptide. Moreover, chelation of intracellular calcium or inhibition of protein kinase C (PKC) totally blocked vWF-induced tyrosine phosphorylation of FAK, indicating that this event is downstream phospholipase A2 and phospholipase C activation. By contrast, tyrosine phosphorylation of Pyk2 was only partially reduced by aspirin and RGDS, and was not affected by either calcium chelation or PKC inhibition, suggesting that activation of this kinase does not require phospholipase-mediated signalling. Both FAK and Pyk2 translocated to the cytoskeleton upon vWF stimulation of human platelets by a mechanism depending on agonist-induced actin polymerisation. Prevention of cytoskeletal relocation of Pyk2 and FAK by cytochalasin D totally blocked vWFinduced tyrosine phosphorylation of both kinases. Finally, phosphorylation of Pyk2 induced by vWF, but not by thrombin, was inhibited by piceatannol, suggesting that this kinase lies downstream Syk. These results demonstrate that both Pyk2 and FAK are involved in platelet stimulation by vWF, but indicate that only Pyk2 may play a role in the early signal transduction events activated by ligand binding to glycoprotein Ib-IX-V.

MCSF expression is induced in healing myocardial infarcts and may regulate monocyte and endothelial cell phenotype

2003 ◽  
Vol 285 (2) ◽  
pp. H483-H492 ◽  
Author(s):  
Nikolaos G. Frangogiannis ◽  
Leonardo H. Mendoza ◽  
Guofeng Ren ◽  
Spyridon Akrivakis ◽  
Peggy L. Jackson ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Nuclear Antigen ◽  
Cell Phenotype ◽  
Early Reperfusion ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein ◽  
Infarcted Myocardium

Myocardial infarction is associated with the rapid induction of mononuclear cell chemoattractants that promote monocyte infiltration into the injured area. Monocyte-to-macrophage differentiation and macrophage proliferation allow a long survival of monocytic cells, critical for effective healing of the infarct. In a canine infarction-reperfusion model, newly recruited myeloid leukocytes were markedly augmented during early reperfusion (5–72 h). By 7 days, the number of newly recruited myeloid cells was reduced, and the majority of the inflammatory cells remaining in the infarct were mature macrophages. Macrophage colony-stimulating factor (MCSF) is known to facilitate monocyte survival, monocyte-to-macrophage conversion, and macrophage proliferation. We demonstrated marked induction of MCSF mRNA in ischemic segments persisting for at least 5 days after reperfusion. MCSF expression was predominantly localized to mature macrophages infiltrating the infarcted myocardium; the expression of the MCSF receptor, c-Fms, a protein with tyrosine kinase activity, was found in these macrophages but was also observed in a subset of microvessels within the infarct. Many infarct macrophages expressed proliferating cell nuclear antigen, a marker of proliferative activity. In vitro MCSF induced monocyte chemoattractant protein-1 synthesis in canine venous endothelial cells. MCSF-induced endothelial monocyte chemoattractant protein-1 upregulation was inhibited by herbimycin A, a tyrosine kinase inhibitor, and by LY-294002, a phosphatidylinositol 3′-kinase inhibitor. We suggest that upregulation of MCSF in the infarcted myocardium may have an active role in healing not only through its effects on cells of monocyte/macrophage lineage, but also by regulating endothelial cell chemokine expression.

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