Syk and paxillin are differentially phosphorylated following adhesion to the plastic substrate in rat alveolar macrophages

Hirano,; Kanno,

doi:10.1046/j.1365-2567.1999.00777.x

Cited by 10 publications

(6 citation statements)

References 23 publications

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“…It has been shown that Syk was tyrosine‐phosphorylated immediately after adhesion to a plastic tissue culture dish in alveolar macrophages 17 . The present study shows that piceatannol (50 µg/ml) inhibited phosphorylation of Syk kinase (Fig.…”

Section: Discussionsupporting

confidence: 60%

“…15 It has been shown that Syk is tyrosine-phosphorylated following adhesion to a plastic dish in alveolar macrophages, and inhibition of Syk phosphorylation is associated with a decrease in macrophage adhesion. 17 Recently we found that krox-20/egr-2 gene expression is up-regulated in response to exposure to fibrous titanium dioxide particles using the differential display technique and the increase in mRNA level of krox-20/egr-2 is not associated with inflammatory responses in rat alveolar macrophages. Several lines of evidence suggest that Krox-20/Egr-2, a zinc-finger transcription factor, plays an essential role in long-term potentiation in hippocampus 18 and is implicated in cell proliferation.…”

Section: Introductionmentioning

confidence: 96%

“…Syk plays a critical role in FcγR‐mediated phagocytosis and the following signal transduction and activated Syk associates with immunoreceptor tyrosine‐based activation motifs (ITAM) by the SH2 domain 15 . It has been shown that Syk is tyrosine‐phosphorylated following adhesion to a plastic dish in alveolar macrophages, and inhibition of Syk phosphorylation is associated with a decrease in macrophage adhesion 17 …”

Section: Introductionmentioning

confidence: 99%

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krox‐20/egr‐2 is up‐regulated following non‐specific and homophilic adhesion in rat macrophages

2002

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SUMMARYMacrophages are known to adhere to a plastic dish via b 2 integrin (CR3) and scavenger receptors. Although their functions such as phagocytosis, endocytosis, and nitric oxide production have been investigated on adherent macrophages in vitro, very little is known about intracellular signals triggered by adhesion to a plastic dish. Recently we reported that the mRNA level of krox-20/egr-2 was significantly increased in rat alveolar macrophages following exposure to fibrous titanium dioxide particles. In the present study we report that up-regulation of krox-20/egr-2 gene expression following adhesion to a plastic dish and homophilic adhesion in rat alveolar macrophages and rat macrophage cell line, NR8383. The mRNA level of krox-20/egr-2 increased with a peak 1 hr after adhesion to a plastic dish in both cell types. Piceatannol inhibited tyrosine-phosphorylation of Syk and decreased both adhesion and krox-20/egr-2 mRNA level. In contrast staurosporine, a serine/threonine kinase inhibitor, increased adherence of macrophages and yet prohibited the adhesion-dependent increase in krox-20/egr-2 gene expression. When NR8383 cells are cultured in suspension, the cells aggregated naturally and produced cell clumps. The mRNA level of krox-20/egr-2 also increased in response to the homophilic intercellular adhesion. The increased mRNA level of krox-20/egr-2 was not caused by inflammatory stimuli, because lipopolysaccharide did not affect the aggregation-dependent up-regulation of krox-20/egr-2 gene. The up-regulation of krox-20/egr-2 gene due to the homophilic cell aggregation was also inhibited either by piceatannol or staurosporine. Those results suggest that krox-20/egr-2 gene expression is triggered by sensing non-specific and homophilic cellular adhesion and the following phosphorylation of signal transducing proteins including Syk and staurosporine-inhibitable kinases.

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Section: Discussionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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krox‐20/egr‐2 is up‐regulated following non‐specific and homophilic adhesion in rat macrophages

2002

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“…Thus, there would appear to be multiple mechanisms for regulating WAVE1 levels in macrophages. Whether the WAVE1 breakdown observed above has any relevance to the regulation of Ca 2ϩ signaling, for example, by adherence in macrophage lineage cells [16,[42][43][44][45][46] is unknown as is its relevance to the calpaindriven regulation of the motility of closely related cell types, namely dendritic cells and osteoclasts [39,47].…”

Section: Discussionmentioning

confidence: 99%

Regulation of WAVE1 expression in macrophages at multiple levels

Dinh

Scholz

Hamilton

2008

Journal of Leukocyte Biology

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M-CSF (or CSF-1) controls macrophage lineage development and function. A CSF-1-dependent culture system was established, which monitored the differentiation of CSF-1-responsive macrophage populations over time and upon adherence. Wiskott-Aldrich syndrome protein verprolin homologous (WAVE) proteins are involved in actin reorganization, a process critical to many cell functions. WAVE2 but not WAVE1 has been considered significant for macrophage function. Using the CSF-1-dependent differentiation system, we were able to demonstrate the contrasting regulation of the expression of WAVE1 and WAVE2; the levels of the latter rose over time and as the macrophage population became adherent, although those of the former increased over time but were down-regulated upon adherence. Evidence was obtained that WAVE1 was also cleaved to a novel, 60-kDa fragment by macrophage adherence and by another pathway involving calpain-mediated proteolysis. Mutagenesis studies indicated that cleavage of WAVE1 by calpain results in the removal of the verprolin-homology, cofilin-like, and acidic domain and thus, the loss of WAVE1 activity. We suggest that WAVE1 is also important for macrophage biology and that it could have separate functions to those of WAVE2.

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“…The adhesion assay was performed as described previously [10]. Cell suspensions (1 × 10 6 /mL: 100 µL) were aliquoted into 96-well culture plates (Costar, New York, NY) and incubated with arsenite and/or TPA for 24 h. After washing twice with PBS, cells were stained with a ×10 dilution of Giemsa solution (Muto Pure Chemicals, Tokyo, Japan) for 15 min.…”

Section: Adhesion Assaymentioning

confidence: 99%

Selective activation of NF‐κB and E2F by low concentration of arsenite in U937 human monocytic leukemia cells

Yamamoto

Hirano

Vogel

et al. 2008

J Biochem & Molecular Tox

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Arsenite has been reported to exert dose-dependent dual effects: triggering apoptosis at relatively high concentrations, whereas inducing partial differentiation at low concentrations in leukemia cells. However, the relevant molecular mechanisms of its action at low and nonapoptotic concentrations remain to be elucidated. We examined the effect of arsenite on activation of key transcription factors in cultured U937 human monocytes/macrophages. Electrophoretic mobility shift assay (EMSA), protein/DNA array and luciferase reporter assay were used to analyze the effect of arsenite on the functional activities of transcription factors. Protein/DNA array analysis showed that activation of E2F was seen after 6-h exposure to 1 and 10 microM arsenite. In contrast, activation of NF-kappaB took place only at 1 microM arsenite, whereas 10 microM arsenite showed no recognizable effect on this nuclear transcription factor in the protein/DNA array analysis. EMSA using a NF-kappaB consensus probe indicates the functional activation of RelB/p50 in the presence of 1 microM arsenite, confirming the above results. Luciferase reporter assay for NF-kappaB showed activation of NF-kappaB in the presence of 1 microM arsenite. Interleukin (IL)-8 and B-cell-activating factor of the tumor necrosis factor family (BAFF) mRNA expression, which have been shown to be regulated through NF-kappaB, were activated in the presence of 1 microM arsenite. These results support the hypothesis that the primary action of nonapoptotic concentrations of arsenite in this cell line is activation of NF-kappaB, signaling as a decision maker for end results such as inflammation disease or cancer. This finding offers the possibility of providing a logical explanation for the observations made by many scientists that chronic exposure of human populations to low doses of arsenic is significantly correlated to clinical signs of inflammation in many tissues.

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Syk and paxillin are differentially phosphorylated following adhesion to the plastic substrate in rat alveolar macrophages

Cited by 10 publications

References 23 publications

krox‐20/egr‐2 is up‐regulated following non‐specific and homophilic adhesion in rat macrophages

krox‐20/egr‐2 is up‐regulated following non‐specific and homophilic adhesion in rat macrophages

Regulation of WAVE1 expression in macrophages at multiple levels

Selective activation of NF‐κB and E2F by low concentration of arsenite in U937 human monocytic leukemia cells

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