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Query: UNIPROT:P05412 (
c-Jun
)
11,453
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We examined the role of Toll-like receptors (TLRs) by using TLR2-deficient (TLR2(-/-)), TLR4-defective (TLR4(d/d)), and double-knockout murine macrophages and human embryonic kidney (HEK) 293 cells transfected with human TLR2 or TLR4 expression plasmids after stimulation with different preparations of the human pathogenic fungus Candida albicans. Compared with wild-type macrophages, TLR2(-/-) and TLR4(d/d) macrophages had impaired recognition of viable C. albicans, whereas antimycotic (AM)-treated C. albicans solely used TLR2 in a TLR4- and
interferon
- gamma -independent manner. In human HEK293 cells, AM-treated C. albicans elicited mainly TLR2-dependent activation. The differences in responsiveness to viable C. albicans, compared with C. albicans treated with cytoplasmic membrane-interacting AMs, suggest specific recognition of different pathogen-associated patterns by TLRs in innate antifungal responses. Our analyses of signal transduction after stimulation of wild-type macrophages with AM-treated C. albicans demonstrated involvement of the transcription factors nuclear factor- kappa B and
c-Jun
/activator protein-1 and of the mitogen-activated protein kinases p38, extracellular-related kinase, and
c-Jun
NH(2)-terminal kinase.
...
PMID:Induction of nuclear factor- kappa B and c-Jun/activator protein-1 via toll-like receptor 2 in macrophages by antimycotic-treated Candida albicans. 1534 44
The interferon-beta promoter has been studied extensively as a model system for combinatorial transcriptional regulation. In virus-infected cells the transcription factors ATF-2,
c-Jun
,
interferon
regulatory factor (IRF)-3, IRF-7 and NF-kappaB, and the coactivators p300/CBP play critical roles in the activation of this and other promoters. It remains unclear, however, why most other combinations of AP-1, IRF and Rel proteins fail to activate the interferon-beta gene. Here we have explored how different IRFs may cooperate with other factors to activate transcription. First we showed in undifferentiated embryonic carcinoma cells that ectopic expression of either IRF-3 or IRF-7, but not IRF-1, was sufficient to allow virus-dependent activation of the interferon-beta promoter. Moreover, the activity of IRF-3 and IRF-7 was strongly affected by promoter context, with IRF-7 preferentially being recruited to the natural interferon-beta promoter. We fully reconstituted activation of this promoter in insect cells. Maximal synergy required IRF-3 and IRF-7 but not IRF-1, and was strongly dependent on the presence of p300/CBP, even when these coactivators only modestly affected the activity of each factor by itself. These results suggest that specificity in activation of the interferon-beta gene depends on a unique promoter context and on the role played by coactivators as architectural factors.
...
PMID:Mechanism for transcriptional synergy between interferon regulatory factor (IRF)-3 and IRF-7 in activation of the interferon-beta gene promoter. 1535 47
Silymarin is a polyphenolic flavonoid that has a strong antioxidant activity and exhibits anticarcinogenic, antiinflammatory, and cytoprotective effects. Although its hepatoprotective effect has been well documented, the effect of silymarin on pancreatic beta-cells is largely unknown. In this study, the effect of silymarin on IL-1beta and/or
interferon
(
IFN
)-gamma-induced beta-cell damage was investigated using RINm5F cells and human islets. IL-1beta and/or IFN-gamma induced cell death in a time-dependent manner in RINm5F cells. The time-dependent increase in cytokine-induced cell death appeared to correlate with the time-dependent nitric oxide (NO) production. Silymarin dose-dependently inhibited both cytokine-induced NO production and cell death in RINm5F cells. Treatment of human islets with a combination of IL-1beta and IFN-gamma (IL-1beta+IFN-gamma), for 48 h and 5 d, resulted in an increase of NO production and the impairment of glucose-stimulated insulin secretion, respectively. Silymarin prevented IL-1beta+IFN-gamma-induced NO production and beta-cell dysfunction in human islets. These cytoprotective effects of silymarin appeared to be mediated through the suppression of
c-Jun
NH2-terminal kinase and Janus kinase/signal transducer and activator of transcription pathways. Our data show a direct cytoprotective effect of silymarin in pancreatic beta-cells and suggest that silymarin may be therapeutically beneficial for type 1 diabetes.
...
PMID:Silymarin protects pancreatic beta-cells against cytokine-mediated toxicity: implication of c-Jun NH2-terminal kinase and janus kinase/signal transducer and activator of transcription pathways. 1545 12
Depending on the type of external signals, T cells can initiate multiple intracellular signaling pathways that can be broadly classified into two groups based on their sensitivity to the immunosuppressive drug cyclosporin A (CsA). Interleukin (IL)-12-mediated
interferon
(
IFN
)-gamma production by activated T cells has been shown to be CsA-insensitive. In this report, we demonstrate that the IL-12-induced CsA-resistant pathway of IFN-gamma production is sensitive to rapamycin. Rapamycin treatment resulted in the aberrant recruitment of Stat3, Stat4, and phospho-
c-Jun
to the genomic promoter region resulting in decreased IFN-gamma transcription. IL-12-induced phosphorylation of Stat3 on Ser-727 was affected by rapamycin, which may be due to the effect of rapamycin on the IL-12-induced interaction between mammalian target of rapamycin (mTOR) and Stat3. In accordance with this, reduction in the mTOR protein level by small interfering RNA resulted in suppression of Stat3 phosphorylation and decreased production of IFN-gamma after IL-12 stimulation. These results suggest that mTOR may play a major role in IL-12-induced IFN-gamma production by activated T cells.
...
PMID:Interleukin-12-induced interferon-gamma production by human peripheral blood T cells is regulated by mammalian target of rapamycin (mTOR). 1552 80
Type I
interferon
(
IFN
)-induced antitumor action is due in part to apoptosis, but the molecular mechanisms underlying
IFN
-induced apoptosis remain largely unresolved. In the present study, we demonstrate that IFN-beta induced apoptosis and the loss of mitochondrial membrane potential (delta psi m) in the murine CH31 B lymphoma cell line, and this was accompanied by the up-regulation of CD95, but not CD95-ligand (CD95-L), tumor necrosis factor (TNF), or TNF-related apoptosis-inducing ligand (TRAIL). Pretreatment with anti-CD95-L mAb partially prevented the IFN-beta-induced loss of delta psi m, suggesting that the interaction of IFN-beta-up-regulated CD95 with CD95-L plays a crucial role in the induction of fratricide. IFN-beta induced a sustained activation of
c-Jun
NH2-terminal kinase 1 (JNK1), but not extracellular signal-regulated kinases (ERKs). The IFN-beta-induced apoptosis and loss of delta psi m were substantially compromised in cells overexpressing a dominant-negative form of JNK1 (dnJNK1), and it was slightly enhanced in cells carrying a constitutively active JNK construct, MKK7-JNK1 fusion protein. The IFN-beta-induced up-regulation of CD95 together with caspase-8 activation was also abrogated in the dnJNK1 cells while it was further enhanced in the MKK7-JNK1 cells. The levels of cellular FLIP (c-FLIP), competitively interacting with caspase-8, were down-regulated by stimulation with IFN-beta but were reversed by the proteasome inhibitor lactacystin. Collectively, the IFN-beta-induced sustained activation of JNK mediates apoptosis, at least in part, through up-regulation of CD95 protein in combination with down-regulation of c-FLIP protein.
...
PMID:Interferon-beta-induced activation of c-Jun NH2-terminal kinase mediates apoptosis through up-regulation of CD95 in CH31 B lymphoma cells. 1574 96
Hemagglutinin B (HagB) is a nonfimbrial adhesin expressed on the surface of Porphyromonas gingivalis and has been implicated as a potential virulence factor involved in mediating the attachment of the bacteria to host cells. However, the molecular mechanisms underlying host responses to HagB and their roles in pathogenesis have yet to be elucidated. Mitogen-activated protein kinases (MAPKs) are activated following engagement of a variety of cell surface receptors via dual tyrosine and threonine phosphorylation and are thought to be involved in various cellular responses. The purpose of this study was to determine the role of intracellular signaling pathways including the MAPKs and NF-kappaB in regulating the production of proinflammatory and anti-inflammatory cytokines following stimulation of murine macrophages with recombinant HagB (rHagB). Stimulation of peritoneal macrophages with rHagB resulted in the production of the proinflammatory cytokines interleukin-12p40 (IL-12p40), gamma
interferon
(IFN-gamma), and tumor necrosis factor alpha, as well as the anti-inflammatory cytokine IL-10. We also demonstrated the activation of extracellular signal-related kinase (ERK),
c-Jun
NH2-terminal protein kinase (JNK), and p38 MAPKs by rHagB-stimulated macrophages. Furthermore, blocking of the ERK and p38 signaling pathways by using specific inhibitors revealed differential regulatory roles in the rHagB-mediated production of proinflammatory and anti-inflammatory cytokines. ERK and p38 were important in down-regulation of IL-12p40 and IFN-gamma production and up-regulation of IL-10 production. The enhanced levels of IL-12p40 in rHagB-stimulated macrophages by inhibition of ERK or p38 activity were partially attributable to the inhibition of IL-10 production. Moreover, NF-kappaB was found to be critical for up-regulation of IL-12p40 and down-regulation of IL-10 production in rHagB-stimulated macrophages. Taken together, our results demonstrate a role for the p38 and ERK pathways and the transcription factor NF-kappaB in modulating key immunoregulatory cytokines involved in the development of immune responses to P. gingivalis HagB.
...
PMID:Role of mitogen-activated protein kinases and NF-kappaB in the regulation of proinflammatory and anti-inflammatory cytokines by Porphyromonas gingivalis hemagglutinin B. 1597 86
Human cytomegalovirus virus (CMV) is a major cause of morbidity and mortality in immunocompromised individuals. Recently, a novel group of cytokines [interleukin (IL)-28A/B and IL-29, also termed
interferon
(
IFN
)-lambdas] has been described. Here, we demonstrate that intestinal epithelial cell (IEC) lines as well as murine and human colonic tissue express the
IFN
-lambda receptor subunits IL-28R and IL-10R2. IL-28A and IL-29 binding to their receptor complex activates ERK-1/2 and stress-activated protein kinase/
c-Jun
NH2-terminal kinase MAPKs and Akt, resulting in increased IL-8 protein expression.
IFN
-lambdas also induce phosphorylation of signal transducer and activator of transcription 1 and significantly increase mRNA expression of suppressor of cytokine signaling 3 and the antiviral proteins myxovirus resistance A and 2',5'-oligoadenylate synthetase. These signals result in an up to 83% reduction of cells positive for human CMV immediate-early protein after human CMV infection. In mice, IL-28A mRNA expression is upregulated after infection with murine CMV in vivo. Both IL-28A and IL-29 significantly decrease cell proliferation but have no effect on Fas-induced apoptosis. In conclusion, IECs express functional receptors for
IFN
-lambdas, which mediate antiviral and antiproliferative signals in IECs, suggesting a potential for therapeutic use in certain viral infections and as (antiproliferative) anticancer therapy.
...
PMID:IL-28A and IL-29 mediate antiproliferative and antiviral signals in intestinal epithelial cells and murine CMV infection increases colonic IL-28A expression. 1605 21
(5R)-5-Hydroxytriptolide (LLDT-8) is a novel analog of triptolide that has antiarthritic, hepatoprotective, and antiallogenic transplantation-rejective effects. In the present study, we report that LLDT-8 inhibited nitric oxide (NO) production and inducible nitric-oxide synthase (iNOS) expression in macrophages. LLDT-8 significantly attenuated NO production, in a dose-dependent manner, in primary peritoneal macrophages and a macrophage cell line of Raw 264.7 cells following stimulation with
interferon
(
IFN
)-gamma, lipopolysaccharide (LPS), and IFN-gamma plus LPS. It also reduced the production of tumor necrosis factor-alpha from LPS-stimulated Raw 264.7 cells. To further elucidate the mechanism responsible for the inhibition of NO, we examined the effect of LLDT-8 on IFN-gamma and LPS-induced iNOS expression. Indeed, LLDT-8 prevented NO generation by inhibiting iNOS expression at mRNA level and protein level, rather than by interfering its enzymatic activity. In IFN-gamma-stimulated Raw 264.7 cells, LLDT-8 suppressed the gene transcription of signal transducer and activator of transcription 1alpha and
interferon
regulatory factor (IRF)-1, but it displayed no apparent effect on IFN-gamma receptor level on cell surface. After LPS challenge, LLDT-8 further abrogated the expression of LPS receptor complex, including CD14, Toll-like receptor 4, and myeloid differentiation protein-2; decreased the LPS-induced phosphorylation of stress-activated protein kinase/
c-Jun
NH(2)-terminal kinase, extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase (MAPK); retarded the degradation of IkappaBalpha; and ameliorated the DNA binding activity of nuclear factor-kappaB (NF-kappaB) to nuclear proteins that accounts for transcriptional regulation of iNOS. Taken together, these results suggest that LLDT-8 reduces NO production and iNOS expression by inhibiting IFN-gamma-triggered IRF-1 expression and LPS-triggered MAPK phosphorylation and NF-kappaB activation.
...
PMID:Inhibition of inducible nitric-oxide synthase expression by (5R)-5-hydroxytriptolide in interferon-gamma- and bacterial lipopolysaccharide-stimulated macrophages. 1616 70
Alcohol abuse reduces response rates to IFN therapy in patients with chronic hepatitis C. To model the molecular mechanisms behind this phenotype, we characterized the effects of ethanol on Jak-Stat and MAPK pathways in Huh7 human hepatoma cells, in HCV replicon cell lines, and in primary human hepatocytes. High physiological concentrations of acute ethanol activated the Jak-Stat and p38 MAPK pathways and inhibited HCV replication in several independent replicon cell lines. Moreover, acute ethanol induced Stat1 serine phosphorylation, which was partially mediated by the p38 MAPK pathway. In contrast, when combined with exogenously applied IFN-alpha, ethanol inhibited the antiviral actions of IFN against HCV replication, involving inhibition of IFN-induced Stat1 tyrosine phosphorylation. These effects of alcohol occurred independently of i) alcohol metabolism via ADH and CYP2E1, and ii) cytotoxic or cytostatic effects of ethanol. In this model system, ethanol directly perturbs the Jak-Stat pathway, and HCV replication. Infection with Hepatitis C virus is a significant cause of morbidity and mortality throughout the world. With a propensity to progress to chronic infection, approximately 70% of patients with chronic viremia develop histological evidence of chronic liver diseases including chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The situation is even more dire for patients who abuse ethanol, where the risk of developing end stage liver disease is significantly higher as compared to HCV patients who do not drink 12.Recombinant interferon alpha (IFN-alpha) therapy produces sustained responses (ie clearance of viremia) in 8-12% of patients with chronic hepatitis C 3. Significant improvements in response rates can be achieved with IFN plus ribavirin combination 456 and pegylated IFN plus ribavirin 78 therapies. However, over 50% of chronically infected patients still do not clear viremia. Moreover, HCV-infected patients who abuse alcohol have extremely low response rates to IFN therapy 9, but the mechanisms involved have not been clarified.MAPKs play essential roles in regulation of differentiation, cell growth, and responses to cytokines, chemokines and stress. The core element in MAPK signaling consists of a module of 3 kinases, named MKKK, MKK, and MAPK, which sequentially phosphorylate each other 10. Currently, four MAPK modules have been characterized in mammalian cells: Extracellular Regulated Kinases (ERK1 and 2), Stress activated/
c-Jun
N terminal kinase (SAPK/JNK), p38 MAP kinases, and ERK5 11. Interestingly, ethanol modulates MAPKs 12. However, information on how ethanol affects MAPKs in the context of innate antiviral pathways such as the Jak-Stat pathway in human cells is extremely limited. When IFN-alpha binds its receptor, two receptor associated tyrosine kinases, Tyk2 and Jak1 become activated by phosphorylation, and phosphorylate Stat1 and Stat2 on conserved tyrosine residues 13. Stat1 and Stat2 combine with the IRF-9 protein to form the transcription factor interferon stimulated gene factor 3 (ISGF-3), which binds to the
interferon
stimulated response element (ISRE), and induces transcription of IFN-alpha-induced genes (ISG). The ISGs mediate the antiviral effects of IFN. The transcriptional activities of Stats 1, 3, 4, 5a, and 5b are also regulated by serine phosphorylation 14. Phosphorylation of Stat1 on a conserved serine amino acid at position 727 (S727), results in maximal transcriptional activity of the ISGF-3 transcription factor complex 15. Although cross-talk between p38 MAPK and the Jak-Stat pathway is essential for IFN-induced ISRE transcription, p38 does not participate in IFN induction of Stat1 serine phosphorylation 1416171819. However, cellular stress responses induced by stimuli such as ultraviolet light do induce p38 MAPK mediated Stat1 S727 phosphorylation 18. In the current report, we postulated that alcohol and HCV proteins modulate MAPK and Jak-Stat pathways in human liver cells. To begin to address these issues, we characterized the interaction of acute ethanol on Jak-Stat and MAPK pathways in Huh7 cells, HCV replicon cells lines, and primary human hepatocytes.
...
PMID:Effect of ethanol on innate antiviral pathways and HCV replication in human liver cells. 1632 17
Heparin is used clinically for the prevention of pregnancy complications associated with prothrombotic disorders, especially antiphospholipid antibody syndrome. Recent studies have suggested that heparin may exert direct effects on placental trophoblast, independently of its anticoagulant activity. We now demonstrate that heparin abrogates apoptosis of primary first trimester villous trophoblast in response to treatment with the pro-inflammatory cytokines
interferon
(
IFN
)-gamma and tumour necrosis factor (TNF)-alpha. This multifunctional glycosaminoglycan also inhibited apoptosis induced by other agents, including staurosporin, broad-spectrum kinase inhibitor and thrombin. Furthermore, heparin attenuated caspase-3 activity, a hallmark of apoptosis, in human first trimester villous and extravillous trophoblast cell lines treated with peptidoglycan, a Toll-like receptor-2 agonist isolated from Staphylococcus aureus. The ability of heparin to antagonize cell death induced by such diverse apoptotic signals suggested that it acts as a survival factor for human trophoblast. We demonstrate that heparin, like epidermal growth factor (EGF) and heparin-binding EGF (HB-EGF), elicits phosphorylation of the EGF receptor and activation of the phosphatidyl inositol 3-kinase (PI3K)-, the extracellular signal-related kinase 1/2 (ERK1/2)- and the
c-Jun
NH2 terminal kinase (JNK)-signal transduction pathways in primary villous trophoblast. In summary, we have demonstrated that heparin activates multiple anti-apoptotic pathways in human trophoblast. Our results suggest that heparin may be useful in the management of at-risk patients, even in the absence of an identifiable thrombophilic disorder.
...
PMID:Heparin prevents programmed cell death in human trophoblast. 1655 79
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