Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidative stress caused by phorbol esters or reactive oxygen up-regulates the class A scavenger receptor (SR-A) in human smooth muscle cells (SMC), which normally do not express this receptor. The increase in SR-A expression correlates with activation of the redox-sensitive transcription factors activating protein-1 c-Jun and CCAAT enhancer-binding protein beta. Here we show that coincubation of SMC with macrophages or oxidized low density lipoproteins (LDL) from macrophage-conditioned medium activates these same regulatory pathways and stimulates SR-A expression. The increased SR-A gene transcription induced by cell-oxidized LDL up-regulated SR-A mRNA and increased by 30-fold the uptake of acetyl LDL, a ligand for the SR-A. Copper-oxidized LDL also increased SR-A receptor expression. Oxidized LDL with a lipid peroxide level of 80-100 nmol/mg of LDL protein and an electrophoretic mobility approximately 1.5 times that of native LDL exhibited the greatest bioactivity. Inhibition of calcium flux suppressed SR-A induction by oxidized LDL. Conversely, calcium ionophore greatly enhanced SR-A up-regulation by oxidized LDL or other treatments that promote intracellular oxidative stress. This enhancement was dependent upon concurrent up-regulation of SMC cyclooxygenase-2 expression and activity and was blocked by the cyclooxygenase-2 inhibitors NS-398 and Resveratrol. In THP-1 cells, oxidized LDL induced monocyte-to-macrophage differentiation and increased SR-A expression. These findings support a role for mildly oxidized LDL in the redox regulation of macrophage differentiation and SR-A expression and suggest that increased vascular oxidative stress may contribute to the formation of both SMC and macrophage foam cells.
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PMID:Class A scavenger receptor up-regulation in smooth muscle cells by oxidized low density lipoprotein. Enhancement by calcium flux and concurrent cyclooxygenase-2 up-regulation. 1083 97

To delineate the functional role of the tumor necrosis factor-alpha (TNF-alpha) activator protein-1 (AP-1)/cAMP-responsive element (CRE)-like binding element (TAC), we transfected the TNF-alpha promoter lacking TAC into THP-1 monocytic cells and stimulated with lipopolysaccharide (LPS). Chloramphenicol acetyltransferase (CAT) activity was reduced by 22-fold, suggesting that TAC plays a role in LPS induction of the TNF-alpha promoter. Exposure to LPS resulted in the maximum release of soluble TNF-alpha by 2 h. Electrophoretic mobility shift assays (EMSA) using the TAC element as a probe showed a unique pattern for LPS-activated cells: the disappearance of the upper band of a doublet seen in untreated and all-trans retinoic acid (ATRA)-treated cells. Supershift analysis identified c-Jun and activating transcription factor-2 (ATF-2) as components of the LPS-stimulated binding complex. Jun N-terminal kinase (JNK), a known phosphorylator of c-Jun and ATF-2, increased in activity in LPS-stimulated monocytes. ATRA, on the contrary, did not activate JNK activity up to 72 h. Nuclear extracts from LPS-stimulated cells showed an increase in phosphorylated c-Jun by immunoblotting. Likewise, phosphorylated c-Jun bound to the TAC element, suggesting that c-Jun is activated by JNK to transactivate the TNF-alpha promoter in LPS-treated monocytes. Thus, phosphorylated c-Jun and ATF-2 play a role in activating the TAC element of the TNF-alpha promoter.
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PMID:A distinct element involved in lipopolysaccharide activation of the tumor necrosis factor-alpha promoter in monocytes. 1095 18

Advanced glycation end product (AGE) activation of the signal-transducing receptor for AGE (RAGE) has been linked to a proinflammatory phenotypic change within cells. However, the precise intracellular signaling pathways involved have not been elucidated. We demonstrate here that human serum albumin modified with N(epsilon)-(carboxymethyl)lysine (CML), a major AGE adduct that progressively accumulates with aging, diabetes, and renal failure, induced nuclear factor (NF)-kappaB-driven reporter gene expression in human monocytic THP-1 cells. The NF-kappaB response was blocked with a synthetic peptide corresponding to the putative ligand-binding domain of RAGE, with anti-RAGE antiserum, and by coexpression of truncated receptors lacking the intracellular domain. Signal transduction from RAGE to NF-kappaB involved the generation of reactive oxygen species, since reporter gene expression was blocked with the antioxidant N-acetyl-L-cysteine. CML-modified albumin produced rapid transient activation of tyrosine phosphorylation, extracellular signal-regulated kinase 1 and 2, and p38 mitogen-activated protein kinase (MAPK), but not c-Jun NH(2)-terminal kinase. RAGE-mediated NF-kappaB activation was suppressed by the selective p38 MAPK inhibitor SB203580 and by coexpression of a kinase-dead p38 dominant-negative mutant. Activation of NF-kappaB by CML-modified albumin increased secretion of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta, and monocyte chemoattractant protein-1) severalfold, and inhibition of p38 MAPK blocked these increases. These results indicate that p38 MAPK activation mediates RAGE-induced NF-kappaB-dependent secretion of proinflammatory cytokines and suggest that accelerated inflammation may be a consequence of cellular activation induced by this receptor.
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PMID:Requirement for p38 and p44/p42 mitogen-activated protein kinases in RAGE-mediated nuclear factor-kappaB transcriptional activation and cytokine secretion. 1137 53

Activator protein 1 (AP-1) binds to the promoters of many genes involved in immune and inflammatory responses. We have previously shown that the p38 mitogen-activated protein (MAP) kinase regulates NF-kappa B-dependent gene expression by modulating the phosphorylation and subsequent activation of TATA-binding protein (TBP). In this study, we asked whether the p38 MAP kinase regulated the transcriptional activity of AP-1. We found that phorbol 12-myristate 13-acetate (PMA) was unable to drive the AP-1-dependent reporter gene in THP-1 cells. PMA activated both the extracellular signal-regulated kinase and c-Jun NH(2)-terminal kinase MAP kinases, but it did not activate the p38 MAP kinase. We found that cells expressing MAP kinase kinase 6(Glu), which is the upstream kinase that activates the p38 MAP kinase, had significantly increased AP-1-dependent gene expression alone and when stimulated with PMA. These cells also had increased phosphorylation of native c-Jun, suggesting that both c-Jun NH(2)-terminal kinase and p38 MAP kinases phosphorylate c-Jun. More importantly, expression of a constitutive active MAP kinase kinase 6(Glu) resulted in the phosphorylation of a His-TBP fusion protein and increased direct interaction of TBP with c-Jun. These findings suggest that in macrophages, the p38 MAP kinase regulates AP-1-driven transcription by modulating the activation of TBP.
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PMID:The absence of activator protein 1-dependent gene expression in THP-1 macrophages stimulated with phorbol esters is due to lack of p38 mitogen-activated protein kinase activation. 1145 54

Inflammatory bowel diseases (IBD)--Crohn's disease and ulcerative colitis--are relapsing chronic inflammatory disorders which involve genetic, immunological, and environmental factors. The regulation of TNF-alpha, a key mediator in the inflammatory process in IBD, is interconnected with mitogen-activated protein kinase pathways. The aim of this study was to characterize the activity and expression of the four p38 subtypes (p38alpha-delta), c-Jun N-terminal kinases (JNKs), and the extracellular signal-regulated kinases (ERK)1/2 in the inflamed intestinal mucosa. Western blot analysis revealed that p38alpha, JNKs, and ERK1/2 were significantly activated in IBD, with p38alpha showing the most pronounced increase in kinase activity. Protein expression of p38 and JNK was only moderately altered in IBD patients compared with normal controls, whereas ERK1/2 protein was significantly down-regulated. Immunohistochemical analysis of inflamed mucosal biopsies localized the main expression of p38alpha to lamina propria macrophages and neutrophils. ELISA screening of the supernatants of Crohn's disease mucosal biopsy cultures showed that incubation with the p38 inhibitor SB 203580 significantly reduced secretion of TNF-alpha. In vivo inhibition of TNF-alpha by a single infusion of anti-TNF-alpha Ab (infliximab) resulted in a highly significant transient increase of p38alpha activity during the first 48 h after infusion. A significant infliximab-dependent p38alpha activation was also observed in THP-1 myelomonocytic cells. In human monocytes, infliximab enhanced TNF-alpha gene expression, which could be inhibited by SB 203580. In conclusion, p38alpha signaling is involved in the pathophysiology of IBD.
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PMID:p38 mitogen-activated protein kinase is activated and linked to TNF-alpha signaling in inflammatory bowel disease. 1199 93

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are drugs very effective to decrease low-density lipoprotein (LDL) cholesterol. In addition, a number of studies suggest that statins have other beneficial clinical effects beyond cholesterol lowering. We recently reported that statins decrease nuclear factor kappa B (NF-kappaB) binding activity in monocytes and vascular smooth muscle cells. We now explored the effect of two different statins, simvastatin and atorvastatin, in the activation of the octamer transcription factor Oct-1 on the monocytic cell line THP-1. Oct-1 is a nuclear factor that represses the transcription of proinflammatory genes such as interleukin-8, CD11c/CD18, vascular cell adhesion molecule-1 (VCAM-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1). Low concentrations of both statins increased Oct-1 DNA binding activity (electrophoretic mobility shift assay) that was resolved into two specific bands. The upper one was supershifted by preincubation of nuclear extracts with anti-Oct-1 antibody. The lower one was supershifted by preincubation of nuclear extracts with an anti-Oct-2 antibody, also partially competed with 100 mol/l excess of cold activator protein-1 (AP-1) and attenuated by anti-c-Jun antibody. Both statins increased Oct-1 and Oct-2 nuclear protein levels (Western blot). In contrast, neither had any effect on PMA-differentiated cells, suggesting a distinct sensitivity between circulating monocytes and resident tissular macrophages. In addition, statins did not increase Oct-lipoprotein lipase binding activity that contains an Oct-1 binding element. The mRNA expression of interleukin-8, a chemokine containing Oct sites in its promoter, was diminished by statin pretreatment. Our results indicate that simvastatin and atorvastatin increase the activity of the transcriptional repressor Oct-1 in mononuclear cells, and could thus contribute to decrease the activation of these cells. These data suggest a possible novel mechanism supporting a certain anti-inflammatory effect of these two 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors.
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PMID:3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors increase the binding activity and nuclear level of Oct-1 in mononuclear cells. 1214 30

The signal-inducible phosphorylation of serines 32 and 36 of I kappa B alpha is critical in regulating the subsequent ubiquitination and proteolysis of I kappa B alpha, which then releases NF-kappa B to promote gene transcription. The multisubunit I kappa B kinase responsible for this phosphorylation contains two catalytic subunits, termed I kappa B kinase (IKK)-1 and IKK-2. BMS-345541 (4(2'-aminoethyl)amino-1,8-dimethylimidazo(1,2-a)quinoxaline) was identified as a selective inhibitor of the catalytic subunits of IKK (IKK-2 IC(50) = 0.3 microm, IKK-1 IC(50) = 4 microm). The compound failed to inhibit a panel of 15 other kinases and selectively inhibited the stimulated phosphorylation of I kappa B alpha in cells (IC(50) = 4 microm) while failing to affect c-Jun and STAT3 phosphorylation, as well as mitogen-activated protein kinase-activated protein kinase 2 activation in cells. Consistent with the role of IKK/NF-kappa B in the regulation of cytokine transcription, BMS-345541 inhibited lipopolysaccharide-stimulated tumor necrosis factor alpha, interleukin-1 beta, interleukin-8, and interleukin-6 in THP-1 cells with IC(50) values in the 1- to 5-microm range. Although a Dixon plot of the inhibition of IKK-2 by BMS-345541 showed a non-linear relationship indicating non-Michaelis-Menten kinetic binding, the use of multiple inhibition analyses indicated that BMS-345541 binds in a mutually exclusive manner with respect to a peptide inhibitor corresponding to amino acids 26-42 of I kappa B alpha with Ser-32 and Ser-36 changed to aspartates and in a non-mutually exclusive manner with respect to ADP. The opposite results were obtained when studying the binding to IKK-1. A binding model is proposed in which BMS-345541 binds to similar allosteric sites on IKK-1 and IKK-2, which then affects the active sites of the subunits differently. BMS-345541 was also shown to have excellent pharmacokinetics in mice, and peroral administration showed the compound to dose-dependently inhibit the production of serum tumor necrosis factor alpha following intraperitoneal challenge with lipopolysaccharide. Thus, the compound is effective against NF-kappa B activation in mice and represents an important tool for investigating the role of IKK in disease models.
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PMID:BMS-345541 is a highly selective inhibitor of I kappa B kinase that binds at an allosteric site of the enzyme and blocks NF-kappa B-dependent transcription in mice. 1240 72

Previous studies have suggested that heterotrimeric G proteins and tyrosine kinases may be involved in lipopolysacchaide (LPS) signaling events. Signal transduction pathways activated by LPS we examined in human pomonocytic THP-l cells. We hypothesized that Gi proteins and Src tyrosine kinase differentially affect mitogen-activated protein (MAP) kinases (MAPK) and nuclear factor kappa(NF-kappaB) activation. Post-receptor coupling to Ga, proteins were examined using pertussis toxin (PTx),which inhibits Galpha i receptor-coupling. The involvement of the Src family of tyrosine kinases was examined using the selective Src tyrosine kinase inhibitor pyrazolopyrimidine-2 (PP2). Pretreatment of THP-1 cells with PTx attenuated LPS-induced activation of c-Jun-N-terminal kinase (JNK) and p38 kinase, and production of tumor necrosis factor-alpha (TN-alpha) and thromboxane B2 (TXB2). Pretreatment with PP2 inhibited TNF-alpha and TxB2 production, but had no effect on p38 kinase or JNK signaling. Therefore, the Ga i-coupled signaling pathways and Src tyrosine kinase-coupled signaling pathways are necessary for LPS-induced TNF-alpha and TxB2 production, but differ in their effects on MAPK activation. Neither PTx nor PP2 inhibited LPS-induced activation of interleukin receptor activated kinase (IRAK) or inhibited translocation of NF-kappaB. However, PP2 inhibited LPS-induced NF-kappaB transactivation of a luciferase reporter gene construct in a concentration-dependent manner. Thus, LPS induction of Src tyrosine kinases may be essential in downstream NF-kappaB tansactivation of genes following DNA binding. PTx had no effect on NF-kaapaB activation of the reporter construct. These data suggest upstream divergence in signaling through Galpha i,pathways leading to MAPK activation and other signaling events leading to IkappaBalpha degradation and NF-kaapaB DNA binding.
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PMID:Implication of Galpha i proteins and Src tyrosine kinases in endotoxin-induced signal transduction events and mediator production. 1270 23

To study the signaling pathway involved in the regulation of galectin-3 expression we used phorbol ester to stimulate macrophage differentiation of THP-1 cells. Treatment with phorbol 12-myristate 13-acetate (PMA) increased significantly the level of expression of galectin-3 in THP-1 cells. PMA-induced galectin-3 overexpression was blocked by: protein kinase C inhibitors staurosporine, calphostin C, and apigenin; tyrosine-specific protein kinase inhibitors genistein and tyrphostin A25; PD 98059, a selective inhibitor of mitogen-activated protein kinase (MAPK) kinase 1 (MEK1 or MKK1); and SB 203580, a specific inhibitor of p38 MAPK. Galectin-3 up-regulation was not affected by exposure to two inhibitors of cAMP-dependent protein kinase (PKA), H-89 and KT5720. Co-transfection of pPG3.5, a plasmid vector containing the rabbit galectin-3 promoter and the constructs pMCL-MKK1 N3 or pRC-RSV-MKK3Glu that constitutively express MKK1 and MKK3, raised the activity of galectin-3 promoter by 185% and 110%, respectively. Co-transfection with a Ha-Ras expression vector stimulated galectin-3 promoter activity approximately 10-fold. Expression of c-Jun or v-Jun raised the level of galectin-3 promoter activity more the three- and fourfold, respectively. Co-transfection of c-Jun and pPG3.5 5'-upstream deletion mutants resulted in a reduction of the galectin-3 promoter activity by 50% to 80%. Transfection of c-Jun, v-Jun or Ha-Ras increased significantly galectin-3 protein in THP-1 cells. These findings indicated that Ras/MEKK1/MKK1-dependent/AP-1 signal transduction pathway plays an important role in the expression of galectin-3 in PMA-stimulated macrophages. We further investigated the effect of modified lipoproteins on galectin-3 expression in macrophages. Murine resident peritoneal macrophages loaded with acetylated low-density lipoprotein (AcLDL) or oxidized LDL (OxLDL) showed increased galectin-3 protein and mRNA. These results showed that treatment of macrophages with PMA or modified lipoproteins results in galectin-3 overexpression. These findings may explain the enhanced expression of galectin-3 in atherosclerotic foam cells and suggest that Ras/MAPK signal transduction pathway is involved in controlling this gene.
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PMID:Galectin-3 expression in macrophages is signaled by Ras/MAP kinase pathway and up-regulated by modified lipoproteins. 1278 25

We examined in vitro effects of 17beta-estradiol (E2) on nerve growth factor production by macrophages derived from monocytic cell line THP-1-or periphereal blood monocytes. E2 and membrane-impermeable bovine serum albumin-conjugated E2 (E2-BSA) enhanced nerve growth factor secretion and mRNA expression in both types of macrophages E2 enhanced nerve growth factor promotor activity in THP-1-derived macrophages and two activator protein-1 binding sites on the promoter were responsible for the enhancement. E2 and E2-BSA enhanced transcriptional activity and DNA binding of activator protein-1. E2 and E2-BSA shifted the activator protein-1 composition from c-Jun homodimers to c-Fos/c-Jun heterodimers. E2 and E2-BSA transiently induced c-Fos mRNA, which was constitutively undetectable in both types of macrophages. Adenylate cyclase inhibitor SQ22536 suppressed E2-induced nerve growth factor production and c-Fos expression. E2 and E2-BSA increased intracellular cyclic adenosine monophosphate level in both types of macrophages. Antisense oligonucleotide against guanine nucleotide-binding protein-coupled receptor, GPR30 suppressed the E2-induced cyclic adenosine monophosphate signal, c-Fos expression, and nerve growth factor secretion in both types of macrophages. These results suggest that E2 may enhance nerve growth factor production by inducing c-Fos expression via cyclic adenosine monophosphate signal in macrophages. These effects may be mediated via GPR30.
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PMID:17Beta-estradiol enhances the production of nerve growth factor in THP-1-derived macrophages or peripheral blood monocyte-derived macrophages. 1463 95


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