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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The 29-kDa amino-terminal fibronectin fragment (FN-f) has a potent chondrolytic effect and is thought to be involved in cartilage degradation in arthritis. However, little is known about signal transduction pathways that are activated by FN-f. Here we demonstrated that FN-f induced nitric oxide (NO) production from human articular chondrocytes. Expression of inducible nitric-oxide synthase (iNOS) mRNA and NO production were observed at 6 and 48 h after FN-f treatment, respectively. Interleukin-1beta (IL-1beta) mRNA up-regulation was stimulated by FN-f in human chondrocytes. To address the possibility that FN-f-induced NO release is mediated by IL-1beta production, the effect of
IL-1
receptor antagonist (IL-1ra) was determined. IL-1ra partially inhibited FN-f-induced NO release although it almost completely inhibited IL-1beta-induced NO release. Tyrosine phosphorylation of
focal adhesion kinase
was induced transiently by FN-f treatment. Blocking antibodies to alpha(5) or beta(1) integrin and Arg-Gly-Asp-containing peptides did not inhibit FN-f-induced NO production. PP2, a Src family kinase inhibitor, or cytochalasin D, which selectively disrupts the network of actin filaments, inhibited both
FAK
phosphorylation and NO production induced by FN-f, but the phosphatidylinositol 3-kinase inhibitor wortmannin had no effect. Analysis of mitogen-activated protein kinases (MAPK) showed activation of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase, and p38 MAPK. High concentrations of SB203580, which inhibit both JNK and p38 MAPK, and PD98059 a selective inhibitor of MEK1/2 that blocks ERK activation, inhibited FN-f induced NO production. These data suggest that
focal adhesion kinase
and MAPK mediate FN-f induced activation of human articular chondrocytes.
...
PMID:Focal adhesion kinase and mitogen-activated protein kinases are involved in chondrocyte activation by the 29-kDa amino-terminal fibronectin fragment. 1167 48
Bone morphogenetic proteins (BMPs) induce cartilage differentiation and morphogenesis. There are profound changes in the cytoskeletal architecture during the morphogenesis of cartilage. To investigate the possibility that morphogenetic signals such as BMPs may regulate chondrocyte phenotype by modulation of cytoskeletal protein expression, we determined whether the expression and distribution of cytoskeletal proteins in chondrocytes are regulated by bone morphogenetic protein 7 (BMP 7),
interleukin 1
(
IL-1
), and cellular context. Addition of BMP 7, a morphogen that induces chondrogenesis, to primary cultures of bovine and murine chondrocytes induced increased expression of four cytoskeletal proteins: tensin, talin, paxillin, and
focal adhesion kinase
(
FAK
). The expression of cytoskeletal proteins is dependent on cellular context; compared to monolayer, chondrocytes in suspension exhibited increased expression of cytoskeletal components. Conversely, addition of
IL-1
, a catabolic cytokine, induced loss of chondrocyte phenotype and decreased the expression of these cytoskeletal components. Treatment of chondrocytes with cytochalasin D (an agent that disrupts the actin cytoskeleton) inhibited BMP 7-induced upregulation of tensin, talin, paxillin, and
FAK
, and blocked the effect of BMP 7 on chondrocyte phenotype. Taken together these data demonstrate that cytoskeletal components play a critical role in the response to morphogens and cytokines in the regulation of chondrocyte phenotype. (c)2001 Elsevier Science.
...
PMID:Regulation of articular chondrocyte phenotype by bone morphogenetic protein 7, interleukin 1, and cellular context is dependent on the cytoskeleton. 1174 Aug 63
Microglia rapidly respond to CNS injury, yet the mechanisms leading to their activation and inactivation remain poorly defined. In particular, few studies have established how interactions between inflammatory mediators affect the innate immune response of microglia. To begin to establish how microglia integrate signals from multiple inflammatory mediators, we examined the effects of interleukin 1beta (IL-1beta), interleukin 6 (IL-6), tumor necrosis factor alpha (TNFalpha), interferon gamma (IFN-gamma), and transforming growth factor beta1 (TGFbeta1) on both newborn and bulk-isolated adult microglia. To assess the functional state of the cells, we assayed the expression of cyclooxygenase 2 (Cox-2), interleukin 6, and tumor necrosis factor alpha, and two protein tyrosine kinases that have been implicated in microglial responses to activational stimuli,
HCK
and
FAK
. These studies demonstrated that IL-1beta, TNFalpha, IL-6, but not IFN-gamma increase the expression of Cox-2, whereas they all increase the expression of
HCK
and
FAK
. In these studies, TGFbeta1 either had no effect, or it decreased basal levels of these proteins. TGFbeta1 blocked activation by IL-1beta when given prior to, or simultaneously with, IL-1beta. TGFbeta1 blocked the induction of the tyrosine kinases, Cox-2, and the induction of IL-6 and TNFalpha mRNAs. However, TGFbeta1 was ineffective in antagonizing the induction of Cox-2 by either IL-6 or TNFalpha. We conclude that the TGFbeta receptor signaling cascades intersect with
IL-1
, but they may not interact with IL-6 or TNFalpha signaling pathways that lead to activation.
...
PMID:Transforming growth factor beta1 prevents IL-1beta-induced microglial activation, whereas TNFalpha- and IL-6-stimulated activation are not antagonized. 1223 48
Bacteria-derived synthetic lipoproteins constitute potent macrophage activators in vivo and are effective stimuli, enhancing the immune response especially with respect to low or non-immunogenic compounds. N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2R,S)-propyl]-(R)-cysteinyl-seryl-(lysyl)3-lysine (P3CSK4), exhibiting one of the most effective lipopeptide derivatives, represents a highly efficient immunoadjuvant in parenteral, oral, nasal and genetic immunization either in combination with or after covalent linkage to antigen. In order to further elucidate its molecular mode of action with respect to the transcriptional level, we focused our investigations on the P3CSK4-induced modulation of gene transcription. We could show that P3CSK4 activates/represses an array of at least 140 genes partly involved in signal transduction and regulation of the immune response. P3CSK4 activates the expression of tumor suppressor protein p53 (p53), c-rel, inhibitor of nuclear factor kappa B (NFkappaB) alpha (IkappaB alpha), type 2 (inducible) nitric oxide (NO) synthase (iNOS), CD40-LR, intercellular adhesion molecule-1 (ICAM-1) and
interleukin 1
/6/15 (
IL-1
/6/15). We detected no activation of heat shock protein (HSP) 27, 60, 84 and 86, osmotic stress protein 94 (Osp 94), IL-12, extracellular signal-regulated protein kinase 1 (ERK1), p38 mitogen activated protein (MAP)-kinase (p38), c-Jun NH2-terminal kinase (JNK), signal transducer and activator of transcription 1 (STAT1), CD14 and caspase genes. Furthermore, we monitored inhibition of STAT6,
Janus kinase 3
(
Jak3
) and cyclin D1/D3 gene transcription after stimulating bone marrow-derived macrophages (BMDM) with lipopeptide. In addition, we monitored significant differences after lipopeptide and lipopolysaccharide (LPS) stimulation of bone marrow-derived murine macrophages. Our findings are of importance for further optimizing both conventional and genetic immunization, and for the development of novel synthetic vaccines.
...
PMID:Lipopeptide adjuvants: monitoring and comparison of P3CSK4- and LPS-induced gene transcription. 1234 44
Monocyte chemoattractant protein-1 (MCP-1) plays a crucial role in the recruitment of monocytes/macrophages associated with several inflammatory diseases and malignancies. The early signal transduction mechanism of macrophage activation in response to in vitro MCP-1 treatment was investigated. The treatment of murine peritoneal macrophages with MCP-1 resulted in a significant enhancement in the tyrosine phosphorylation of cellular proteins, which peaked within 2.5-5 min of MCP-1 treatment. The MCP-1-induced tyrosine phosphorylation of cellular proteins involved the phosphorylation of non-receptor tyrosine kinases Lyn,
JAK2
, cytoskeletal binding protein paxillin and downstream transcription factors STAT3 and STAT5. Immunoflourescence microscopical studies on MCP-1-treated macrophages showed the cellular localization of the tyrosine-phosphorylated proteins and bundling of actin filaments at the focal adhesion points. MCP-1-induced association of focal adhesion proteins Lyn/phospho-paxillin with CCR2 was also observed by co-precipitation. Inhibitor studies with genistein on MCP-1-induced macrophage TNF and
IL-1
production additionally supported the role of protein tyrosine phosphorylation in the process of macrophage activation with MCP-1. Present investigations suggest that the early events in the tyrosine kinase signal transduction pathway for macrophage activation in response to MCP-1 probably involve (1) CCR2 receptor dimerization, (2) enhanced tyrosine phosphorylation and assembly of focal adhesion complex, and (3) the activation of JAK/STAT pathway in the murine peritoneal macrophages.
...
PMID:Tyrosine phosphorylation-mediated signal transduction in MCP-1-induced macrophage activation: role for receptor dimerization, focal adhesion protein complex and JAK/STAT pathway. 1234 47
Focal adhesion complexes are actin-rich, cytoskeletal structures that mediate cell adhesion to the substratum and also selectively regulate signal transduction pathways required for interleukin (IL)-1beta signaling to the MAP kinase, ERK.
IL-1
-induced ERK activation is markedly diminished in fibroblasts deprived of focal adhesions whereas activation of p38 and JNK is unaffected. While
IL-1
signaling is known to involve the activity of protein and lipid kinases including MAP kinases,
FAK
, and PI3K, little is known about the role of phosphatases in the regulation of
IL-1
signal generation and attenuation. Here we demonstrate that SHP-2, a protein tyrosine phosphatase present in focal adhesions, modulates
IL-1
-induced ERK activation and the transient actin stress fiber disorganization that occurs following
IL-1
treatment in human gingival fibroblasts. Using a combination of immunoblotting, immunoprecipitation, and immunostaining we show that SHP-2 is present in nascent focal adhesions and undergoes phosphorylation on tyrosine 542 in response to
IL-1
stimulation. Blocking anti-SHP-2 antibodies, electoporated into the cytosol of fibroblasts, inhibited
IL-1
-induced ERK activation, actin filament assembly, and cell contraction, indicating a role for SHP-2 in these processes. In summary, our data indicate that SHP-2, a focal adhesion-associated protein, participates in
IL-1
-induced ERK activation likely via an adaptor function.
...
PMID:The protein tyrosine phosphatase SHP-2 regulates interleukin-1-induced ERK activation in fibroblasts. 1272 Dec 96
Serum amyloid A (SAA) is known to be a precursor of amyloid A (AA) protein in AA (secondary) amyloidosis and SAA1 to be mainly involved in AA amyloidosis. We established an SAA isoform real-time quantitative RT-PCR assay and found that beta-2 microglobulin is more stable as an internal control than GAPDH and beta-actin for our system. Either IL-6 and IL-1beta or IL-6 and TNFalpha, but not IL-1beta and TNFalpha, induced the synergistic induction of SAA1 and SAA2 genes. Anti-IL-6 receptor monoclonal antibody completely inhibited the synergistic induction of SAA1 and SAA2 during triple stimulation with IL-6, IL-1beta, and TNFalpha, but,
IL-1
receptor antagonist or anti-TNFalpha monoclonal antibody was only partially inhibited in HepG2, Hep3B, and PLC/PRF/5 cells. Although the SAA1 promoter has no STAT3 consensus sequence, the
JAK2
inhibitor-AG490 reduced SAA1 gene expression to 30%, suggesting the involvement of STAT3. We were able to demonstrate that IL-6 plays a critical role in the synergistic induction of human SAA gene when stimulated with proinflammatory cytokines.
...
PMID:IL-6 plays a critical role in the synergistic induction of human serum amyloid A (SAA) gene when stimulated with proinflammatory cytokines as analyzed with an SAA isoform real-time quantitative RT-PCR assay system. 1473 13
Leptin and leukemia inhibitory factor (LIF) have been implicated as important mediators of implantation. The present study was designed to investigate whether leptin can directly regulate the expression of LIF and its receptor (LIF-R) in human endometrial cells and/or whether leptin-induced effects are linked to, or regulated in part by
IL-1
signaling. Primary endometrial cells and endometrial epithelial cell lines (HES and Ishikawa cells) were cultured for 24-48 h in a medium containing insulin (5 microg/ml) and leptin (3, 10, and 62 nm) or IL-1beta (0.6, 3, and 10 nm) in the presence or absence of cytokines and/or receptor antagonists. The endpoints included phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the relative levels of LIF, LIF-R, IL-1beta,
IL-1
receptor antagonist (IL-1Ra) and
IL-1
receptor type I (IL-1R tI) as determined by ELISA or Western blotting techniques. Leptin treatment increases the level of phosphorylated STAT3, LIF-R, and LIF. Leptin also increases the levels of
IL-1
ligand, receptor, and antagonist as was previously reported. Blockade of OB-R with antibodies or with a specific OB-R inhibitor (leptin peptide antagonist-2) abrogated leptin-induced effects, suggesting that leptin binding to its receptor activates
Janus kinase 2
/STAT3 signaling. Treatment of endometrial cells with IL-1beta also results in elevated levels of LIF-R. Interestingly, the inhibition of IL-1R tI with a specific antibody or with IL-1Ra negatively affects both leptin-induced and
IL-1
-induced effects on LIF-R levels. Abnormal endometrial LIF expression has been associated with human infertility and leptin has profound effects on the levels of LIF,
IL-1
, and their cognate receptors in vitro. Thus, it is tempting to speculate that leptin's role in vivo could include the regulation of other key cytokines to be fundamental to endometrial receptivity during implantation (i.e. LIF and
IL-1
).
...
PMID:Leptin-induced increase in leukemia inhibitory factor and its receptor by human endometrium is partially mediated by interleukin 1 receptor signaling. 1514 89
Sepsis results in hepatic "growth hormone (GH) resistance" with reductions in plasma IGF-I despite a two- to fourfold increase in circulating GH. In this study, we examine the effects of
IL-1
on GH receptor (GHR) expression, GH signaling (via the JAK/STAT and MAPK pathways), and the induction of gene expression [IGF-I mRNA and serine protease inhibitor (Spi) 2.1] by GH in CWSV-1 hepatocytes. Incubation of cells with IL-1beta (10 ng/ml, 24 h) had no effect on the relative abundance of GHR or signaling proteins
JAK2
, STAT5b, and ERK1/2 in cell lysates. Baseline phosphorylation of GHR,
JAK2
, STAT5b, and ERK1/2 was minimal. After GH stimulation, tyrosine phosphorylation of GHR,
JAK2
, STAT5b, and ERK1/2 increased 2- to 10-fold. However, neither the time course nor the magnitude of GHR,
JAK2
, and ERK1/2 phosphorylation by GH were significantly altered by
IL-1
. The GH-induced translocation of STAT5b to the nucleus was not prevented by
IL-1
. Although phosphorylated STAT5 in nuclear extracts from GH +
IL-1
cells was decreased by 24% (vs. controls) 15 min after GH stimulation, this did not result in reduced STAT5-DNA binding activity. Pretreatment with
IL-1
did not significantly decrease IGF-I mRNA stability. We conclude that
IL-1
only minimally affects the time course of
JAK2
/STAT5 and MAPK signaling by GH. Therefore, an inhibitory effect of
IL-1
on IGF-I and Spi 2.1 mRNA synthesis by GH represents the most likely mechanism for
IL-1
-mediated GH resistance.
...
PMID:Interleukin-1 inhibits the induction of insulin-like growth factor-I by growth hormone in CWSV-1 hepatocytes. 1583 12
The objective of the present study was to investigate the effect of leptin, alone or in combination with
IL-1
, on nitric oxide synthase (NOS) type II activity in vitro in human primary chondrocytes, in the mouse chondrogenic ATDC5 cell line, and in mature and hypertrophic ATDC5 differentiated chondrocytes. For completeness, we also investigated the signalling pathway of the putative synergism between leptin and
IL-1
. For this purpose, nitric oxide production was evaluated using the Griess colorimetric reaction in culture medium of cells stimulated over 48 hours with leptin (800 nmol/l) and
IL-1
(0.025 ng/ml), alone or combined. Specific pharmacological inhibitors of NOS type II (aminoguanidine [1 mmol/l]), janus kinase (JAK)2 (tyrphostin AG490 and Tkip), phosphatidylinositol 3-kinase (PI3K; wortmannin [1, 2.5, 5 and 10 micromol/l] and LY294002 [1, 2.5, 5 and 10 micromol/l]), mitogen-activated protein kinase kinase (MEK)1 (PD098059 [1, 5, 10, 20 and 30 micromol/l]) and p38 kinase (SB203580 [1, 5, 10, 20 and 30 micromol/l]) were added 1 hour before stimulation. Nitric oxide synthase type II mRNA expression in ATDC5 chondrocytes was investigated by real-time PCR and NOS II protein expression was analyzed by western blot. Our results indicate that stimulation of chondrocytes with
IL-1
results in dose-dependent nitric oxide production. In contrast, leptin alone was unable to induce nitric oxide production or expression of NOS type II mRNA or its protein. However, co-stimulation with leptin and
IL-1
resulted in a net increase in nitric oxide concentration over
IL-1
challenge that was eliminated by pretreatment with the NOS II specific inhibitor aminoguanidine. Pretreatment with tyrphostin AG490 and Tkip (a SOCS-1 mimetic peptide that inhibits
JAK2
) blocked nitric oxide production induced by leptin/
IL-1
. Finally, wortmannin, LY294002, PD098059 and SB203580 significantly decreased nitric oxide production. These findings were confirmed in mature and hypertrophic ATDC5 chondrocytes, and in human primary chondrocytes. This study indicates that leptin plays a proinflammatory role, in synergy with
IL-1
, by inducing NOS type II through a signalling pathway that involves
JAK2
, PI3K, MEK-1 and p38 kinase.
...
PMID:Signalling pathway involved in nitric oxide synthase type II activation in chondrocytes: synergistic effect of leptin with interleukin-1. 1589 45
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