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)

AMP-activated protein kinase (AMPK) is tightly regulated by the cellular AMP:ATP ratio and plays a central role in the regulation of energy homeostasis and metabolic stress. A pharmacological activator of AMPK, 5-amino-4-imidazole carboxamide riboside (AICAR) inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory cytokines (tumor necrosis factor alpha, interleukin-1beta, and interleukin-6) and inducible nitric oxide synthase in primary rat astrocytes, microglia, and peritoneal macrophages. AICAR attenuates the LPS-induced activation of nuclear factor kappaB via downregulation of IkappaB kinase alpha/beta activity. It also inhibits nuclear translocation of CCAAT/enhancer-binding protein (C/EBP) transcription factor by inhibiting the expression of C/EBP-delta in brain glial cells. The dominant negative form of AMPKalpha2 (D157A) and its antisense documents a possible role of AMPK in the regulation of the cellular proinflammatory process. AICAR also inhibited the production of inflammatory mediators in serum and their expression in CNS of rats injected with a sublethal dose of LPS by intraperitoneal injection. These observations in cultured cells as well as in the animal model suggest that AICAR may be of therapeutic value in treating inflammatory diseases.
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PMID:5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside inhibits proinflammatory response in glial cells: a possible role of AMP-activated protein kinase. 1472 46

5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR) can be used as an experimental tool to activate 5'-AMP-activated protein kinase (AMPK) and has been shown to improve insulin sensitivity. In parallel adiponectin also seems to activate AMPK and to improve insulin sensitivity. We have investigated the effects of AICAR on the gene expression of adiponectin and on gene expression and release of cytokines in human adipose tissue in vitro. AICAR stimulated AMPK alpha1 activity 3-4-fold (p<0.001), and dose-dependently increased adiponectin mRNA levels with significant stimulation (2-4-fold) at AICAR concentrations of 0.5-2mM (p<0.05). The adipose tissue protein release of tumor necrosis factor-alpha (TNF- alpha) and interleukin-6 (IL-6) was decreased by AICAR (p<0.05). In conclusion, AICAR stimulated adipose tissue AMPK alpha1 activity and adiponectin gene expression, while attenuating the release of TNF-alpha and IL-6. Reduced concentrations of these cytokines and increased levels of adiponectin might play a role for the insulin sensitizing effects of AICAR.
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PMID:AICAR stimulates adiponectin and inhibits cytokines in adipose tissue. 1503 79

Following exercise, AMP-activated protein kinase (AMPK) activity is increased several fold in rat liver and adipose tissue as well as muscle; however, the mechanism by which this occurs is not known. Interleukin-6 (IL-6) is released from muscle in large amounts during and after sustained physical activity resulting in up to 100-fold increases in its plasma concentration, from 1-2 ng/ml to 50-100 ng/ml. We report here that incubation with IL-6 (30-120 ng/ml) increases the phosphorylation of AMPK (an indicator of its activation) and that of its target molecule, acetyl CoA carboxylase (ACC), in both extensor digitorum longus muscle and cultured F422a adipocytes. To assess more directly whether IL-6 regulates AMPK in vivo during exercise, measurements were carried out in skeletal muscle, liver, and adipose tissue of 3-month-old IL-6 knockout (IL-6(-/-)) and C57 black control mice. In agreement with previous studies in the rat, in control mice P-AMPK and P-ACC abundance was increased by 30-150% in the three tissues in response to exercise with the greatest increases in skeletal muscle. In contrast, in IL-6(-/-) mice, we found that the abundance of both P-AMPK and P-ACC was lower (60-90%) in muscle and adipose tissue at rest. Also the absolute increases in P-AMPK caused by exercise were diminished compared to those in control mice, although percentage increases were similar. In liver, decreases in P-AMPK and P-ACC in the IL-6(-/-) mice were more modest and the increases in their abundance caused by exercise were indistinguishable from those of control mice. The results indicate that IL-6 can activate AMPK in muscle and adipose tissue, and that this contributes to, but does not fully account for, the increase in AMPK activity in these tissues in response to exercise. They also suggest that a genetic lack of IL-6 is associated with a decrease in AMPK activity.
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PMID:AMPK activity is diminished in tissues of IL-6 knockout mice: the effect of exercise. 1521 49

Though known as a sensor of energy balance, AMP-activated protein kinase (AMPK) was recently shown to limit damage and apoptotic activity and contribute to the late preconditioning in heart. Interleukin-6 was also reported to involve in anti-apoptosis and cardio-protection in myocardium. Interestingly, both AMPK activity and IL-6 level were increased in response to ischemia, hypertrophy and oxidative stress. To determine whether AMPK activation will promote IL-6 production, cardiac fibroblasts (CFs) from mice were incubated with AMPK activator, 5-aminoimidazole-4-carboxamide-1-4-ribofuranoside (AICAR). The results demonstrated that AICAR time and dose-dependently stimulated IL-6 production by ELISA and immunofluorescence. Pretreatment with p38 mitogen-activated protein kinase (MAPK) inhibitor blocked AICAR-induced IL-6 production; furthermore, AICAR-activated p38 MAPK phosphorylation by Western blot. To confirm that the increase in IL-6 production is ascribed to AMPK activation, we used another known AMPK activator, metformin. It also dose-dependently potentiated IL-6 production in CFs, and this potentiation could be reversed by p38 MAPK inhibitor. In conclusion, AMPK activation promoted IL-6 production in CFs via p38 MAPK-dependent pathway.
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PMID:AICAR stimulates IL-6 production via p38 MAPK in cardiac fibroblasts in adult mice: a possible role for AMPK. 1622 18

Although interleukin-6 (IL-6) has been associated with insulin resistance, little is known regarding the effects of IL-6 on insulin sensitivity in humans in vivo. Here, we show that IL-6 infusion increases glucose disposal without affecting the complete suppression of endogenous glucose production during a hyperinsulinemic-euglycemic clamp in healthy humans. Because skeletal muscle accounts for most of the insulin-stimulated glucose disposal in vivo, we examined the mechanism(s) by which IL-6 may affect muscle metabolism using L6 myotubes. IL-6 treatment increased fatty acid oxidation, basal and insulin-stimulated glucose uptake, and translocation of GLUT4 to the plasma membrane. Furthermore, IL-6 rapidly and markedly increased AMP-activated protein kinase (AMPK). To determine whether the activation of AMPK mediated cellular metabolic events, we conducted experiments using L6 myotubes infected with dominant-negative AMPK alpha-subunit. The effects described above were abrogated in AMPK dominant-negative-infected cells. Our results demonstrate that acute IL-6 treatment enhances insulin-stimulated glucose disposal in humans in vivo, while the effects of IL-6 on glucose and fatty acid metabolism in vitro appear to be mediated by AMPK.
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PMID:Interleukin-6 increases insulin-stimulated glucose disposal in humans and glucose uptake and fatty acid oxidation in vitro via AMP-activated protein kinase. 1700 32

Exercise induces an increase in glucose transport in muscle. As the acute increase in glucose transport reverses, it is replaced by an increase in insulin sensitivity. Interleukin-6 (IL-6) increases with exercise and has been reported to activate AMP-activated protein kinase (AMPK). Based on this information, we hypothesized that IL-6 would result in an increase in muscle insulin sensitivity. Rat epitrochlearis and soleus muscles were incubated with 120 ng/ml IL-6. Exposure to IL-6 induced a modest acute increase in glucose transport and was followed 3.5 h later by an increase in insulin sensitivity in epitrochlearis but not soleus muscles. IL-6 also brought about an increase in AMPK phosphorylation in epitrochlearis muscles. We conclude that exposure of fast-twitch muscle to 120 ng/ml IL-6 increases insulin sensitivity by activating AMPK. However, exposure of epitrochlearis muscles to 10 ng/ml IL-6, a concentration >100-fold higher than that attained in plasma during exercise, had no effect on glucose transport or insulin sensitivity. These findings provide evidence that the increases in glucose transport and insulin sensitivity induced by IL-6 are pharmacological rather than physiological effects. We interpret our results as evidence that the increase in IL-6 during exercise does not play a role in the exercise-induced increases in muscle glucose uptake and insulin sensitivity.
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PMID:IL-6 increases muscle insulin sensitivity only at superphysiological levels. 1732 67

Over the past decade, an epidemic of obesity has developed throughout the Western World. In recent years, significant interest has focused on the role of the AMP-activated protein kinase (AMPK) as a potential therapeutic target for the treatment of obesity and type 2 diabetes and is such the focus of this review. Specifically, the potential role of AMPK in skeletal muscle metabolism as it relates to the insulin sensitizing effects of exercise and the hormones, leptin, adiponectin, ciliary neurotrophic factor and interleukin-6 are discussed. We caution that despite the convincing associations between the activation of AMPK signalling and the restoration of insulin sensitivity, future studies in genetic models of AMPK deficiency or constitutive activation within skeletal muscle are needed to evaluate the quantitative role of AMPK and to validate whether strategies designed to activate skeletal muscle AMPK may be important for regulating whole-body insulin sensitivity.
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PMID:The AMP-activated protein kinase: role in regulation of skeletal muscle metabolism and insulin sensitivity. 1750 87

Low-grade chronic inflammation is a feature of Type 2 diabetes and appears to play a pathogenetic role in insulin resistance. It is well known that cytokines, besides their immunoregulatory roles, are important players in metabolism. Moreover, it has become evident that skeletal muscles express several cytokines, which belong to distinct cytokine classes. IL-6 (interleukin-6) is a pleiotropic cytokine produced by virtually all multinucleated cells including skeletal myocytes where it is produced in response to contraction. IL-6 is subsequently released into the circulation, where it works in a hormone-like fashion to induce lipolysis and fat oxidation. In more recent experiments, it has been shown that IL-6 infusion increases glucose disposal during a hyperinsulinaemic euglycaemic clamp in healthy humans. IL-6 treatment of myotubes increases fatty acid oxidation, basal and insulin-stimulated glucose uptake and translocation of GLUT4 to the plasma membrane. Furthermore, IL-6 rapidly and markedly increases AMPK (AMP-activated protein kinase) and the metabolic effects of IL-6 were abrogated in AMPK dominant negative-infected cells. Finally, IL-6 mediates anti-inflammatory effects by stimulating the production of anti-inflammatory cytokines and by suppressing TNFalpha (tumour necrosis factor alpha) production. We suggest that IL-6 and other muscle-derived cytokines (myokines) may play a role in defending Type 2 diabetes.
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PMID:IL-6 signalling in exercise and disease. 1795 34

Alcoholic fatty liver is a potentially pathologic condition which can progress to steatohepatitis, fibrosis, and cirrhosis if alcohol consumption is continued. Alcohol exposure may induce fatty liver by increasing NADH/NAD(+) ratio, increasing sterol regulatory element-binding protein-1 (SREBP-1) activity, decreasing peroxisome proliferator-activated receptor-alpha (PPAR-alpha) activity, and increasing complement C3 hepatic levels. Alcohol may increase SREBP-1 activity by decreasing the activities of AMP-activated protein kinase and sirtuin-1. Tumor necrosis factor-alpha (TNF-alpha) produced in response to alcohol exposure may cause fatty liver by up-regulating SREBP-1 activity, whereas betaine and pioglitazone may attenuate fatty liver by down-regulating SREBP-1 activity. PPAR-alpha agonists have potentials to attenuate alcoholic fatty liver. Adiponectin and interleukin-6 may attenuate alcoholic fatty liver by up-regulating PPAR-alpha and insulin signaling pathways while down-regulating SREBP-1 activity and suppressing TNF-alpha production. Recent studies show that paracrine activation of hepatic cannabinoid receptor 1 by hepatic stellate cell-derived endocannabinoids also contributes to the development of alcoholic fatty liver. Furthermore, oxidative modifications and inactivation of the enzymes involved in the mitochondrial and/or peroxisomal beta-oxidation of fatty acids could contribute to fat accumulation in the liver.
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PMID:Molecular mechanisms of alcoholic fatty liver. 1903 84

The dynamic control of energy metabolism is dependent on balancing energy demand with energy supply. In mammals this balance is maintained through the integration of many different cytokine signals that communicate the nutrient status of the organism to the hypothalamus, liver and skeletal muscle. Adipose tissue and resident macrophages secrete many of these cytokine factors including leptin, tumour necrosis factor a, adiponectin, interleukin-6 and resistin. Other secreted factors including ciliary neurotrophic factor and ghrelin have also been shown to regulate energy metabolism. The AMP-activated protein kinase (AMPK) has emerged as an important integrator of these cytokine signals regulating both central and peripheral pathways controlling food intake, energy expenditure and substrate utilization and as such is the focus of this review.
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PMID:Cytokine Regulation of AMPK signalling. 1927 72


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