Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P05231 (interleukin-6)
23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many cytokines mediate their effects through Jak/STAT signaling pathways providing many opportunities for cross-talk between different cytokines. We examined the interaction between two cytokine families, gp130-related cytokines and interferon-gamma (IFN-gamma), which are coexpressed in the nervous system during acute trauma and pathological conditions. Typical nerve cells show an IFN-gamma response that is restricted to activating STAT1, with minor activation of STAT3. IFN-gamma elicited a pronounced STAT3 response in cells pre-treated for 5-7 h with ciliary neurotrophic factor (CNTF), leukemia inhibitory factor or interleukin-6. CNTF or interleukin-6 induced an IFN-gamma STAT3 response in a variety of cells including SH-SY5Y human neuroblastoma, HMN-1 murine motor neuron hybrid cells, rat sympathetic neurons and human hepatoma HepG2 cells. The enhancement was measured as an increase in tyrosine phosphorylated STAT3, in STAT3-DNA binding and in STAT-luciferase reporter gene activity. The enhanced STAT3 response was not due to an increase in overall STAT3 levels but was dependent upon ongoing protein synthesis. The induction by CNTF was inhibited by the protein kinase C inhibitor, BIM, and the MAPK-kinase inhibitor, U0126. Further, H-35 hepatoma cells expressing gp130 receptor chimeras lacking either the SHP-2 docking site or the Box 3 STAT binding sites failed to enhance the IFN-gamma STAT3 response. These results provide evidence for an interaction between gp130 and IFN-gamma cytokines that can significantly alter the final cellular response to IFN-gamma.
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PMID:Induction of an interferon-gamma Stat3 response in nerve cells by pre-treatment with gp130 cytokines. 1451 Nov 21

The cytokine tumor necrosis factor alpha (TNF-alpha) stimulates the NF-kappaB, SAPK/JNK, and p38 mitogen-activated protein (MAP) kinase pathways by recruiting RIP1 and TRAF2 proteins to the tumor necrosis factor receptor 1 (TNFR1). Genetic studies have revealed that RIP1 links the TNFR1 to the IkappaB kinase (IKK) complex, whereas TRAF2 couples the TNFR1 to the SAPK/JNK cascade. In transfection studies, RIP1 and TRAF2 stimulate p38 MAP kinase activation, and dominant-negative forms of RIP1 and TRAF2 inhibit TNF-alpha-induced p38 MAP kinase activation. We found TNF-alpha-induced p38 MAP kinase activation and interleukin-6 (IL-6) production impaired in rip1(-/-) murine embryonic fibroblasts (MEF) but unaffected in traf2(-/-) MEF. Yet, both rip1(-/-) and traf2(-/-) MEF exhibit a normal p38 MAP kinase response to inducers of osmotic shock or IL-1alpha. Thus, RIP1 is a specific mediator of the p38 MAP kinase response to TNF-alpha. These studies suggest that TNF-alpha-induced activation of p38 MAP kinase and SAPK/JNK pathways bifurcate at the level of RIP1 and TRAF2. Moreover, endogenous RIP1 associates with the MAP kinase kinase kinase (MAP3K) MEKK3 in TNF-alpha-treated cells, and decreased TNF-alpha-induced p38 MAP kinase activation is observed in Mekk3(-/-) cells. Taken together, these studies suggest a mechanism whereby RIP1 may mediate the p38 MAP kinase response to TNF-alpha, by recruiting the MAP3K MEKK3.
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PMID:The death domain kinase RIP1 is essential for tumor necrosis factor alpha signaling to p38 mitogen-activated protein kinase. 1458 94

Diabetic patients are susceptible to severe inflammatory periodontitis manifesting as swollen gingiva with bleeding, but the underlying mechanism is not well understood. Our purpose was to determine the effect of a high glucose (HG) condition on the interleukin-6/soluble interleukin-6 receptor (IL-6/sIL-6R)-induced activation of signaling and vascular endothelial growth factor (VEGF) expression in human gingival fibroblasts (HGFs). In this study, HGFs were cultured for at least two passages under a normal glucose (NG; 5.5 mM) condition or high glucose (25 mM) condition. Importantly, the HG condition significantly induced expression of gp130 mRNA in HGFs compared with levels in control cells. Consistent with the expression of its mRNA, the HG condition also increased the expression of gp130 protein, and phosphorylation of the tyrosine residue by gp130 was enhanced significantly by IL-6/sIL-6R stimulation. Furthermore, the HG condition enhanced the IL-6/sIL-6R-induced phosphorylation of p44/42 MAPK and led to subsequent activation of CCAAT/enhancer binding protein in nuclei. In contrast, there was no significant difference in phosphorylation of JNK between the HG and NG condition. Interestingly, HGFs increased IL-6/sIL-6R-induced VEGF165 mRNA expression and VEGF165 secretion under the HG condition compared with levels under the NG condition. In contrast, the induction of VEGF165 secretion was partially inhibited by PD98059 (selective p44/42 MAPK inhibitor) under the HG condition. In addition, the VEGF165 secretion was completely inhibited by the combination of PD98059 and SP600125 (JNK inhibitor). Our findings suggest that the HG condition indirectly increases VEGF expression via activation of gp130-mediated p44/42 MAPK-CCAAT/enhancer binding protein signaling in HGFs. Thus, elevated VEGF secretion in HGFs under the HG condition may play a role in the development of the severe periodontitis observed in diabetic patients.
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PMID:High glucose enhances interleukin-6-induced vascular endothelial growth factor 165 expression via activation of gp130-mediated p44/42 MAPK-CCAAT/enhancer binding protein signaling in gingival fibroblasts. 1467 17

The mitogen-activated protein (MAP) cascade leading to the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) is critical for regulating myeloma cell growth; however, the relationship of ERK1/2 activity with vascular endothelial growth factor (VEGF) production and the effects of its downmodulation in myeloma cells are not elucidated. We found that the treatment with MAP/ERK kinase 1 (MEK1) inhibitors PD98059 or PD184352 produced a reduction of phosphorylated ERK1/2 (p-ERK1/2) levels in myeloma cells of more than 80% and prevented the increase of p-ERK1/2 induced by interleukin-6 (IL-6). MEK1 inhibitors also induced a significant inhibition of myeloma cell proliferation and blunted the stimulatory effect induced by IL-6. A significant inhibition of basal VEGF secretion by myeloma cells as well as a suppression of the stimulatory effect of IL-6 on VEGF was observed by either PD98059 or PD184352. Moreover, we also found that the PI3K kinase inhibitors, but not p38 MAPK inhibitors, reduced VEGF secretion by myeloma cells and increase the inhibitory effect of MEK1 inhibitors. In an 'in vitro' model of angiogenesis, we found that MEK1 inhibitors impair vessel formation induced by myeloma cells and restored by VEGF treatment, suggesting that the downmodulation of ERK1/2 activity reduces myeloma-induced angiogenesis by inhibiting VEGF secretion.
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PMID:Downmodulation of ERK protein kinase activity inhibits VEGF secretion by human myeloma cells and myeloma-induced angiogenesis. 1473 74

The physiological benefit of the febrile response is poorly understood. Here we show that fever-range thermal stress enhances the function of the L-selectin lymphocyte homing receptor through an interleukin-6 (IL-6)-dependent signaling mechanism. Thermal stimulation of L-selectin adhesion in vitro and in vivo is mediated by engagement of the gp130 signal-transducing chain by IL-6 and a soluble form of the IL-6 receptor-alpha (sIL-6Ralpha) binding subunit. Thermal control of adhesion is maintained in IL-6-deficient mice through a gp130-dependent compensatory mechanism mediated by IL-6-related cytokines (i.e., oncostatin M [OSM], leukemia inhibitory factor [LIF], and IL-11). Combined biochemical and pharmacological inhibitor (PD98059, U0126, SB203580, SP600125) approaches positioned MEK1/ERK1-2, but not p38 MAPK or JNK, in the IL-6/sIL-6Ralpha signaling pathway upstream of activation of L-selectin/cytoskeletal interactions and L-selectin avidity/affinity. These results highlight a role for gp130-linked IL-6/sIL-6Ralpha transsignaling in amplifying lymphocyte trafficking during febrile inflammatory responses.
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PMID:Central role of IL-6 receptor signal-transducing chain gp130 in activation of L-selectin adhesion by fever-range thermal stress. 1473 59

In this study, we examined the signal transduction of dibutyryl cyclic adenosine monophosphate (dBcAMP) to stimulate the release of nitric oxide (NO) and interleukin-6 (IL-6) from J774 macrophages. These actions of dBcAMP were diminished by the presence of the inhibitors of protein kinase A (PKA), protein kinase C (PKC), p38 MAPK and nuclear factor-kappa B (NF-kappaB). In contrast, Go 6976 and PD98059 had no significant effects. Consistently, dBcAMP caused membrane translocation of PKCbetaII, delta, mu, lambda and zeta isoforms, and increased atypical protein kinase C (aPKC) and p38 MAPK activities. The nuclear translocation and DNA-binding study revealed that dBcAMP stimulated NF-kappaB, activator protein-1 (AP-1), and CAAT/enhancer-binding protein (c/EBPbeta). Via PKA, PKC and p38 MAPK-dependent signals, dBcAMP also induced inhibitory subunit of NF-kappaB (IkappaB) degradation, IkappaB kinase (IKK) activation, nuclear translocation of NF-kappaB subunit p65 and its association with the CREB-binding protein (CBP). These results illustrate that PKA activation in macrophages is able to stimulate PKC and p38 MAPK, which lead to IKK-dependent NF-kappaB activation and contribute to the induction of inducible nitric oxide synthase (iNOS) and IL-6 genes.
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PMID:PKA-dependent activation of PKC, p38 MAPK and IKK in macrophage: implication in the induction of inducible nitric oxide synthase and interleukin-6 by dibutyryl cAMP. 1475 42

Reactive gliosis is a hallmark of disease-, trauma-, and chemical-induced damage to the central nervous system. The signaling pathways associated with this response to neural injury remain to be elucidated, but recent evidence implicates the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. Here, we used the known dopaminergic neurotoxicant, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), to selectively damage striatal dopaminergic nerve terminals and elicit a glial response. We then analyzed changes in gene expression and protein phosphorylation, in vivo, to identify ligands and mediators of the JAK-STAT pathway that accompany glial activation. Administration of MPTP caused rapid tyrosine (Tyr-705) phosphorylation and nuclear translocation of STAT3 in striatal astrocytes, prior to the induction of glial fibrillary acidic protein mRNA and protein. Pharmacological protection of dopaminergic nerve terminals with nomifensine abolished MPTP-mediated phosphorylation and translocation of STAT3 and prevented induction of astrogliosis. Among the Janus kinase family of tyrosine kinases, only JAK2 was associated with the phosphorylation of STAT3 after MPTP and, inhibition of JAK2 by AG490, in vivo, attenuated both the phosphorylation of STAT3 and induction of GFAP. The p44/42 mitogen-activated protein kinase (MAPK; ERK1/2) also was activated by MPTP, but was not associated with activation of STAT3, because serine (Ser-727) was not phosphorylated. The mRNA for ligands of the gp130-JAK/STAT3 signaling pathway, interleukin-6, leukemia inhibitory factor, and oncostatin M were elevated prior to activation of STAT3 and induction of astrogliosis; neuroprotection with nomifensine blocked these effects of MPTP. Taken together, our results suggest that the gp130-mediated activation of JAK2/STAT3 signaling pathway may play a key role in the induction of astrogliosis.
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PMID:Induction of gp130-related cytokines and activation of JAK2/STAT3 pathway in astrocytes precedes up-regulation of glial fibrillary acidic protein in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of neurodegeneration: key signaling pathway for astrogliosis in vivo? 1499 42

Ischemic delayed neuronal cell death (apoptosis) in the hippocampus is prevented by PACAP. PACAP inhibits the increasing activity of the MAP kinase family, especially on JNK/SAPK and p38, thereby protecting against apoptotic cell death. After the ischemia-reperfusion, both pyramidal cells and astrocytes increased their expression of PACAP receptors (PAC1-Rs). The pyramidal cells degenerated but reactive astrocytes increased their expression of PAC1-R. PACAP does not only inhibit apoptotic cell death directly, but also affects astrocytes through PAC1-Rs. Interleukin-6 (IL-6), produced in astrocytes, has several effects on the prevention of brain ischemia and trauma and stimulating neuronal growth. IL-6 secretion into the CSF was markedly stimulated after PACAP infusion, suggesting that PACAP stimulates IL-6 secretion from astrocytes. We studied the effects of PACAP on the wild type and IL-6 KO mice after brain ischemia. In wild-type animals, PACAP significantly inhibited cell death, but in IL-6 KO animals, no cytoprotective effect of PACAP was seen. These results suggest that PACAP inhibits apoptotic cell death partly through IL-6. It is considered that PACAP itself and IL-6, stimulated secretion by PACAP, both synergistically inhibit the JNK/SAPK and p38 signaling pathway, thereby protecting against neuronal cell death.
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PMID:[Prevention of delayed neuronal cell death by PACAP and its molecular mechanism]. 1505 39

Parathyroid hormone-related protein (PTHrP) regulates proliferation and differentiation of osteoblastic cells via binding to the parathyroid hormone receptor (PTH-1R). The cAMP-dependent protein kinase A pathway governs the majority of these effects, but recent evidence also implicates the MAPK pathway. MC3T3-E1 subclone 4 cells (MC4) were treated with the MAPK inhibitor U0126 and PTHrP. In differentiated MC4 cells, osteocalcin and bone sialoprotein gene expression were both down-regulated by PTHrP and also by inhibition of the MAPK pathway. PTHrP-mediated down-regulation of PTH-1R mRNA and up-regulation of c-fos mRNA were MAPK-independent, whereas PTHrP stimulation of fra-2 and interleukin-6 (IL-6) mRNA was MAPK-dependent. Luciferase promoter assays revealed that regulation of IL-6 involved the cAMP-dependent protein kinase A and MAPK pathways with a potential minor role of the protein kinase C pathway, and a promoter region containing an activator protein-1 site was necessary for PTHrP-induced IL-6 gene transcription. An alternative pathway, through cAMP/Epac/Rap1/MAPK, mediated ERK phosphorylation but was not sufficient for IL-6 promoter activation. Phosphorylation of the transcription factor CREB was also necessary but not sufficient for PTHrP-mediated IL-6 promoter activity. Most interesting, a bidirectional effect was found with PTHrP increasing phosphorylated ERK in undifferentiated MC4 cells but decreasing phosphorylated ERK in differentiated cells. These data indicate that inactivation of the MAPK pathway shows differential regulation of PTHrP-stimulated activator protein-1 members, blocks PTHrP-stimulated IL-6, and synergistically down-regulates certain osteoblastic markers associated with differentiation. These novel findings indicate that the MAPK pathway plays a selective but important role in the actions of PTHrP.
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PMID:Impact of the mitogen-activated protein kinase pathway on parathyroid hormone-related protein actions in osteoblasts. 1512 46

The interleukin-6 (IL6) family of cytokines signals through the common receptor subunit gp130, and subsequently activates Stat3, MAPK, and PI3K. Stat3 controls cell death and tissue remodeling in the mouse mammary gland during involution, which is partially induced by IL6 and LIF. However, it is not clear whether Stat3 activation is mediated solely through the gp130 pathway or also through other receptors. This question was explored in mice carrying two distinct mutations in the gp130 gene; one that resulted in the complete ablation of gp130 and one that led to the loss of Stat3 binding sites (gp130Delta/Delta). Deletion of gp130 specifically from mammary epithelium resulted in a complete loss of Stat3 activity and resistance to tissue remodeling comparable to that seen in the absence of Stat3. A less profound delay of mammary tissue remodeling was observed in gp130Delta/Delta mice. Stat3 tyrosine and serine phosphorylation was still detected in these mice suggesting that Stat3 activation could be the result of gp130 interfacing with other receptors. Experiments in primary mammary epithelial cells and transfected COS-7 cells revealed a p44/42 MAPK and EGFR-dependent Stat3 activation. Moreover, the gp130-dependent EGFR activation was independent of EGF ligands, suggesting a cytoplasmic interaction and cross-talk between these two receptors. These experiments establish that two distinct Stat3 signaling pathways emanating from gp130 are utilized in mammary tissue.
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PMID:Mammary gland remodeling depends on gp130 signaling through Stat3 and MAPK. 1529 6


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