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)

Growth-related oncogene protein-alpha (GRO-alpha) is a member of the C-X-C chemokine family with a wide variety of biological activities. We studied the production of GRO-alpha by human umbilical vein endothelial cells (HUVEC) in response to the stimulation with soluble form of interleukin-6 receptor alpha (sIL-6R). sIL-6R stimulated HUVEC to express GRO-alpha mRNA and secrete GRO-alpha protein in concentration-and time-dependent manners. The sIL-6R-induced GRO-alpha expression was inhibited by the pretreatment of the cells with AG490, a janus kinase 2 (JAK2) inhibitor, or with U0126, a MAP kinase-ERK kinase (MEK) inhibitor. sIL-6R also induced the phosphorylation of both Src homology 2-protein tyrosine phosphatase-2 (SHP-2), signal transducer and activator of transcription 3 (STAT3) and MEK. AG490 pretreatment inhibited the MEK phosphorylation but did not affect the STAT3 phosphorylation. We conclude that sIL-6R induces GRO-alpha expression in HUVEC through the activation of JAK2 and MEK.
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PMID:Production of growth related oncogene protein-alpha in human umbilical vein endothelial cells stimulated with soluble interleukin-6 receptor-alpha: role of signal transducers, janus kinase 2 and mitogen-activated kinase kinase. 1200

Interleukin-6 (IL-6) is regarded as an endogenous mediator of lipopolysaccharide (LPS)-induced fever. IL-6 is thought to act on the brain at sites that lack a blood-brain barrier, the circumventricular organs (CVOs). Cells that are activated by IL-6 respond with nuclear translocation of the signal transducer and activator of transcription 3 molecule (STAT3) and can be detected by immunohistochemistry. We investigated whether the LPS-induced release of IL-6 into the systemic circulation was accompanied by a nuclear STAT3 translocation within the sensory CVOs. Treatment with LPS (100 microg/kg) led to a slight (1 h) and then a strong increase (2-8 h) in plasma IL-6 levels, which started to decline at the end of the febrile response. Administration of both pyrogens LPS and IL-6 (45 microg/kg) induced a febrile response with IL-6, causing a rather moderate fever compared with the LPS-induced fever. Nuclear STAT3 translocation in response to LPS was observed within the vascular organ of the lamina terminalis (OVLT) and the subfornical organ (SFO) 2 h after LPS treatment. To investigate whether this effect was mediated by IL-6, the cytokine itself was systemically applied and indeed an identical pattern of nuclear STAT3 translocation was observed. However, nuclear STAT3 translocation already occurred 1 h after IL-6 application and proved to be less effective compared with LPS treatment when analyzing OVLT and SFO cell numbers that showed nuclear STAT3 immunoreactivity after the respective pyrogen treatment. Our observations represent the first molecular evidence for an IL-6-induced STAT3-mediated genomic activation of OVLT and SFO cells and support the proposed role of these brain areas as sensory structures for humoral signals created by the activated immune system and resulting in the generation of fever.
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PMID:Selected contribution: role of IL-6 in LPS-induced nuclear STAT3 translocation in sensory circumventricular organs during fever in rats. 1201 87

Cardiotrophin-1 (CT-1) is an Interleukin-6 family cytokine with known hypertrophic and protective effects in cardiac cells. CT-1 and the corticotrophin releasing hormone-like hormone urocortin protect cardiac myocytes by the same p42/44 mitogen activated protein kinase (p42/44 MAPK) dependent pathway. We investigated whether urocortin is also hypertrophic in cardiac myocytes and whether it shares a common pathway with CT-1 for this effect. Moreover, we also investigated, for the first time whether CT-1 and urocortin can induce hypertrophy in cultured adult as opposed to neonatal cardiac cells. Urocortin and CT-1 caused hypertrophy (as measured by an increase in cell area and enhanced protein: DNA ratio) in both adult and neonatal rat cultured cardiac myocytes. The hypertrophic effect of CT-1 was dependent on the signal transducer and activator of transcription 3 (STAT3) pathway but the hypertrophic effect of urocortin was independent of this pathway. In contrast, inhibition of the protective p42/p44 MAPK pathway has no effect on the hypertrophic effect of CT-1 or urocortin. Additionally, inhibition of the STAT3 pathway has no effect on the protective effect of CT-1 or urocortin. These results identify urocortin as a novel hypertrophic and protective agent whose hypertrophic effect is mediated by a distinct pathway to that activated by CT-1, although the two factors mediate protection via the same pathway.
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PMID:Cardiotrophin-1 and urocortin cause protection by the same pathway and hypertrophy via distinct pathways in cardiac myocytes. 1202 5

Interleukin-6 (IL-6) is a multifunctional cytokine that may have a role in energy regulation. Using a recombinant adeno-associated viral vector expressing murine interleukin-6 (rAAV-IL-6), we examined the chronic effects of centrally expressed IL-6 on food intake, body weight and adiposity in male Sprague-Dawley rats, and investigated the underlying mechanisms. Direct delivery of rAAV-IL-6 into rat hypothalamus suppressed weight gain and visceral adiposity without affecting food intake over a 5-week period. rAAV-IL-6 enhanced uncoupling protein 1 (UCP1) protein levels in interscapular brown adipose tissue (BAT). To investigate if the induction of UCP1 and the reduction in body weight are dependent on sympathetic innervation of BAT, we administered rAAV-IL-6 or a control vector into the hypothalamus of rats in which the interscapular BAT was unilaterally denervated. Over 21 days, there was no difference in food consumption or body weight between rAAV-IL-6- and control vector-treated rats. rAAV-IL-6 delivery increased UCP1 mRNA and protein levels in innervated BAT pads but not denervated BAT pads. Hypothalamic IL-6 signal transduction, indicated by phosphorylated signal transducer and activator of transcription 3 (P-STAT3) levels, was elevated by 2.6-fold at day 21, but returned to control levels by day 35. However, the suppressor of cytokine signaling-3 mRNA level was significantly elevated both at day 21 and day 35. These data demonstrate that chronic elevation of IL-6 in the CNS reduces body weight gain and visceral adiposity without affecting food intake. The mechanism involves sympathetic induction of UCP1 in BAT and, presumably, enhanced thermogenesis in BAT. Furthermore, chronic central IL-6 stimulation desensitizes IL-6 signal transduction characterized by reversal of elevated P-STAT3 levels.
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PMID:Induction of uncoupling protein 1 by central interleukin-6 gene delivery is dependent on sympathetic innervation of brown adipose tissue and underlies one mechanism of body weight reduction in rats. 1243 26

Changes in transcription factors (TFs) accompany many types of cell stresses. By using electrophoretic mobility assays we show that the DNA binding of signal transducer and activator of transcription 3 (STAT3) is activated in rat liver by heat shock and ischemia-reperfusion. Northern blot and Western blot analysis reveal an increase of the mRNA and protein level of this transcription factor. Under both conditions the phosphorylation of pre-existing STAT3 is prompt and precedes the increase in the STAT3 protein. The activation: (1) is functional, i.e. is followed by the transcription of the target gene alpha(1)-acid glycoprotein (2) is strongly inhibited by pretreatment with the interleukin-1 receptor antagonist before heat shock but only slightly by pretreatment before ischemia-reperfusion (3) might, at least in part, be mediated by a cytokine cascade involving also interleukin-6. These results are consistent with the hypothesis that different kinds of stress can activate a number of common TFs.
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PMID:Activation of signal transducer and activator of transcription 3 in rat liver after heat shock and reperfusion stress. 1253 Dec 44

In rats, activation of the cytokine-inducible transcription factor signal transducer and activator of transcription 3 (Stat3) is impaired in the liver after ethanol administration. The aim was to examine Stat3 expression, localization, and activity in alcoholic liver disease (ALD) in humans. Explanted livers of ALD patients were compared to normal and primary biliary cirrhosis livers. Protein expression, DNA-binding, and subcellular localization of Stat3 was examined by Western blotting, electrophoretic mobility shift assays, and immunohistochemistry; and interleukin-6, Stat3, and suppressor of cytokine signaling (SOCS)-3 mRNA expression by quantitative polymerase chain reaction. Stat3 proteins increased markedly in ALD, mainly in hepatocyte and proliferating biliary epithelial cell nuclei. In contrast to normal and primary biliary cirrhosis livers where Stat3 DNA-binding occurred normally, no Stat3 DNA-binding complexes were observed in ALD, although the tyrosine and serine phosphorylation of Stat3 was not altered. Elevated interleukin-6 mRNA was found in ALD whereas Stat3 and suppressor of cytokine signaling-3 mRNA levels were decreased. Although end-stage ALD is characterized by up-regulation of Stat3 proteins, this transcription factor appears to be functionally inactive. Furthermore, decreased transcription of the Stat3 gene in ALD might also affect cytoplasmic reserves of inactivated Stat3 in the long term. Impaired activation and restoration of Stat3 might thus contribute to the development of cell damage leading to liver cirrhosis in ALD.
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PMID:Expression and DNA-binding activity of signal transducer and activator of transcription 3 in alcoholic cirrhosis compared to normal liver and primary biliary cirrhosis in humans. 1254 16

Interleukin-6 (IL-6) is a multifunctional cytokine playing roles in the immune system, hematopoiesis, and acute phase reactions. IL-6 also regulates the growth of various types of human malignant tumors. Here we demonstrate that IL-6-induced gene expression was suppressed by a specific heat-shock protein 90 (Hsp90) inhibitor, geldanamycin (GA) in human hepatoma Hep3B cells. GA also suppressed the IL-6-induced activation of signal transducer and activator of transcription 3 (STAT3) in a human embryonic kidney carcinoma 293T cells. This inhibitory effect of GA on STAT3 activation was reversed by overexpression of Hsp90. Furthermore, Hsp90 directly bound to STAT3 via its N-terminal region, which interacted with GA. We provide evidence that the action of GA on IL-6 functions was due to the inhibition of direct physical interactions between STAT3 and Hsp90, which represents a novel role of Hsp90 in the IL-6 signaling pathways.
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PMID:Involvement of heat-shock protein 90 in the interleukin-6-mediated signaling pathway through STAT3. 1255 50

Adrenocorticotropic hormone (ACTH) release from anterior pituitary corticotropes is greatly increased during peripheral inflammation induced by lipopolysaccharide (LPS) administration. Interleukin-6 (IL-6) is thought to participate in LPS-induced ACTH release, but whether or not corticotropes are directly targeted by this cytokine is unclear. Therefore, we investigated the expression and activation of IL-6 signaling components in the pituitary of rats 2 and 4 h after administration of LPS (250 microg/kg). Intraperitoneal LPS treatment provoked the nuclear translocation of signal transducer and activator of transcription 3 (STAT-3) and Fos expression in the anterior pituitary lobe, as demonstrated by immunohistochemistry. By using in situ hybridization, we demonstrated that suppressor of cytokine signaling 3 (SOCS-3) and c-fos mRNAs were significantly induced by the LPS treatment in the anterior lobe of the pituitary. Dual in situ hybridization revealed that most corticotropes expressed IL-6 receptor and gp130 mRNAs, and that 2 h after LPS treatment, SOCS-3 and c-fos mRNAs were induced in corticotropes. Our results suggest that LPS-induced IL-6 could regulate the hypothalamo-pituitary-adrenal axis by directly targeting corticotropes during peripheral inflammation.
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PMID:In vivo activation of the interleukin-6 receptor/gp130 signaling pathway in pituitary corticotropes of lipopolysaccharide-treated rats. 1262 39

Whereas interleukin-6 (IL-6) is a proinflammatory cytokine, IL-10 is an anti-inflammatory cytokine. Although signal transducer and activator of transcription 3 (STAT3) is essential for the function of both IL-6 and IL-10, it is unclear how these two cytokines have such opposing functions. Here we show that suppressor of cytokine signaling 3 (SOCS3) is a key regulator of the divergent action of these two cytokines. In macrophages lacking the Socs3 gene or carrying a mutation of the SOCS3-binding site in gp130, the lipopolysaccharide-induced production of tumor necrosis factor (TNF) and IL-12 is suppressed by both IL-10 and IL-6. SOCS3 specifically prevents activation of STAT3 by IL-6 but not IL-10. Taken together, these data indicate that SOCS3 selectively blocks signaling by IL-6, thereby preventing its ability to inhibit LPS signaling.
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PMID:IL-6 induces an anti-inflammatory response in the absence of SOCS3 in macrophages. 1277 70

Sepsis induces an early inflammatory cascade initiated by the innate immune response. This often results in the development of multisystem organ failure. We examined the role of CD40, a costimulatory molecule that is integral in adaptive immunity, by using a murine model of polymicrobial sepsis. CD40 knockout (KO) mice had delayed death and improved survival after cecal ligation and puncture (CLP). In addition, they had less remote organ injury as manifested by reduced pulmonary capillary leakage. The improvements in survival and remote organ dysfunction in CD40 KO mice were associated with reduced interleukin-6 (IL-6) and IL-10 levels in serum and bronchoalveolar lavage fluid compared to the levels in wild-type (WT) controls. Furthermore, in contrast to WT mice, CD40 KO mice had no induction of the Th1 cytokines IL-12 and gamma interferon in serum or lungs after CLP. The alterations in cytokine production in CD40 KO mice were associated with similar changes in transcription factor activity. After CLP, CD40 KO mice had attenuated activation of nuclear factor kappaB and signal transducer and activator of transcription 3 in both the lung and the liver. Finally, WT mice had increased expression of CD40 on their alveolar macrophages. These data highlight the importance of CD40 activation in the innate immune response during polymicrobial sepsis and the subsequent development of remote organ dysfunction.
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PMID:CD40 contributes to lethality in acute sepsis: in vivo role for CD40 in innate immunity. 1276 Nov 37


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