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: EC:2.7.11.10 (IKK)
4,900 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Insulin suppresses the release of non-esterified fatty acids from adipocytes and suppresses glucose production from hepatocytes, but stimulates glucose uptake by skeletal muscle, liver and adipose tissue. Insulin resistance, the failure of an ample supply of insulin to mediate these effects, is an early and fundamental defect in type 2 diabetes (T2D) associated with obesity. Adipose tissue not only acts as an energy depot, but also secretes a variety of endocrine, paracrine and autocrine factors, which regulate energy metabolism and insulin activity. In addition, adipose tissue from obese individuals has a distinct secretory profile that alters both adipocyte function and overall in vivo insulin sensitivity. Obesity is coupled to insulin resistance and diabetes through the action of adipose-derived factors, in a process that involves intricate signaling pathways and transcriptional regulators in various cell types of adipose tissue, in addition to cross-talk between adipose and non-adipose tissues. Thus, the dissection of the specific pathways that contribute to insulin resistance in obese individuals is a crucial component in understanding obesity-linked T2D. In this review, recent in vitro and in vivo data that implicate the IKK (inhibitor of kappaB kinase)/NFkappaB pathway, a component of both fatty acid and inflammatory cytokine signaling cascades, in the regulation of insulin sensitivity are discussed, and the value of this pathway as a therapeutic target in T2D is evaluated.
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PMID:The adipocyte IKK/NFkappaB pathway: a therapeutic target for insulin resistance. 1933 55

Insulin-resistant states are commonly associated with chronic inflammation and hepatic overproduction of apolipoprotein B100 (apoB100), leading to hypertriglyceridemia and a metabolic dyslipidemic profile. Molecular mechanisms linking hepatic inflammatory cascades and the pathways of apoB100-lipoprotein production are, however, unknown. In the present study, we employed a diet-induced, insulin-resistant hamster model, as well as cell culture studies, to investigate the potential link between activation of hepatic inflammatory nuclear factor-kappaB (NF-kappaB) signaling cascade and the synthesis and secretion of apoB100-containing lipoproteins. Using an established insulin-resistant animal model, the fructose-fed hamster, we found that feeding fructose (previously shown to induce hepatic inflammation) for as little as 4 days reduced hepatic IkappaB (inhibitor of NF-kappaB) level, indicating activation of the inflammatory NF-kappaB cascade. Importantly, IKK (IkappaB kinase) inhibition was found to suppress apoB100 overproduction in fructose-fed hamster hepatocytes. As IKK, the upstream activator of NF-kappaB has been shown to inhibit insulin signaling, and insulin is a major regulator of apoB100, we modulated IKK activity in primary hamster hepatocytes and HepG2 cells and assessed the effects on hepatic apoB100 biosynthesis. Inhibition of the IKK-NF-kappaB pathway by BMS345541 and activation of the pathway by adenoviral-mediated IKK overexpression decreased and increased newly synthesized apoB100 levels, respectively. Pulse-chase and metabolic labeling experiments revealed that IKK activation regulates apoB100 levels at the levels of apoB100 biosynthesis and protein stability. Inhibition of the IKK-NF-kappaB pathway significantly enhanced proteasomal degradation of hepatic apoB100, while direct IKK activation led to reduced degradation and increased apoB100 mRNA translation. Together, our results reveal important links between modulation of the inflammatory IKK-NF-kappaB signaling cascade and hepatic synthesis and secretion of apoB100-containing lipoproteins. Hepatic inflammation may be an important underlying factor in hepatic apoB100 overproduction observed in insulin resistance.
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PMID:Inflammatory NF-kappaB activation promotes hepatic apolipoprotein B100 secretion: evidence for a link between hepatic inflammation and lipoprotein production. 1934 10

When modeling cell signaling networks, a balance must be struck between mechanistic detail and ease of interpretation. In this paper we apply a fuzzy logic framework to the analysis of a large, systematic dataset describing the dynamics of cell signaling downstream of TNF, EGF, and insulin receptors in human colon carcinoma cells. Simulations based on fuzzy logic recapitulate most features of the data and generate several predictions involving pathway crosstalk and regulation. We uncover a relationship between MK2 and ERK pathways that might account for the previously identified pro-survival influence of MK2. We also find unexpected inhibition of IKK following EGF treatment, possibly due to down-regulation of autocrine signaling. More generally, fuzzy logic models are flexible, able to incorporate qualitative and noisy data, and powerful enough to produce quantitative predictions and new biological insights about the operation of signaling networks.
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PMID:Fuzzy logic analysis of kinase pathway crosstalk in TNF/EGF/insulin-induced signaling. 1934 94

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common liver disease in industrialized countries. Thus, the discovery of food components that would ameliorate NAFLD is of interest. Various mushrooms have been used in folk medicine for the treatment of lifestyle diseases in eastern countries and several compounds that modulate immune system, lower blood lipid levels, inhibit tumor and viral action have been isolated from them. In this study, we tested whether feeding Panellus serotinus (Mukitake) to db/db mice protects them from hepatic injury. After 4 weeks of feeding, hepatomegaly, hepatic triglyceride accumulation and elevated hepatic injury markers in serum were markedly alleviated in Mukitake-fed db/db mice compared with control mice. These effects were partly attributable to the enhancement of lipolytic enzyme activity and the suppression of lipogenic enzyme activities due to the Mukitake diet. The severe hyperinsulinemia in control db/db mice tended to attenuate in Mukitake-fed mice due to an enhanced production of adiponectin, which improves insulin sensitivity. Moreover, production of monocyte chemoattractant protein 1 (MCP1), an inflammatory cytokine, was markedly suppressed by the Mukitake diet. In addition, water-soluble extracts of Mukitake powder showed an inhibitory effect on inhibitor of kappaB (IkappaB) kinase (IKK) beta, whose activation is required for nuclear factor kappaB (NFkappaB)-mediated inflammatory response. We speculate that the development and progression of NAFLD was prevented by the reduction of MCP1 production through the interference in the IKKbeta-NFkappaB signaling pathway in Mukitake-fed db/db mice.
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PMID:Mukitake mushroom (Panellus serotinus) alleviates nonalcoholic fatty liver disease through the suppression of monocyte chemoattractant protein 1 production in db/db mice. 1942 19

Obesity and hypertension are the two major risk factors that contribute to the progression of end-stage renal disease. To examine whether hypertension further exacerbates oxidative stress and vascular dysfunction and inflammation in obese rats, four groups of male Sprague-Dawley rats were fed either a normal (7% fat) or high-fat (36% fat) diet for 6 weeks and osmotic pumps were implanted to deliver ANG (angiotensin II) or vehicle for an additional 4 weeks.Treatment with the high-fat diet did not alter ANG-induced hypertension compared with the normal diet (174 +/- 6 compared with 170 +/- 5 mmHg respectively). Treatment with the high-fat diet increased body weight gain and plasma leptin levels and induced insulin resistance in normotensive and ANG-induced hypertensive rats. Plasma TBARS (thiobarbituric acid-reacting substances), a measure of oxidative stress, were elevated in high-fat diet-fed rats compared with controls (11.2 +/-1 compared with 8.4 +/- nmol/ml respectively) and was increased further in ANG-induced hypertensive rats fed a high-fat diet (18.8 +/-2.2 nmol/ml). Urinary nitrite excretion was also decreased in rats fed a high-fat diet without or with ANG infusion compared with controls. Afferent arteriolar relaxation to acetylcholine was impaired in rats fed the high-fat diet without or with ANG infusion. Renal cortical TNF-alpha(tumour necrosis factor-alpha), COX-2(cyclo-oxygenase-2) and phospho-IKK (inhibitor of nuclear factor k B kinase) expression increased in high-fat diet-fed rats compared with normal diet-fed rats. The increases in phospho-IKK and COX-2 expression were elevated further in ANG-induced hypertensive rats fed the high-fat diet.These results suggest that ANG-induced hypertension exacerbates oxidative stress and renal inflammation without further impairment in vascular dysfunction in high-fat diet-induced obesity.
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PMID:Obesity is the major contributor to vascular dysfunction and inflammation in high-fat diet hypertensive rats. 1972 60

Obesity leads to tissue inflammation and insulin resistance, which are features of metabolic diseases such as type 2 diabetes. Chiang et al. (2009) now show that the IkappaB kinase IKKepsilon is an important link between obesity and inflammation and may be a new therapeutic target for treating obesity-related metabolic diseases.
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PMID:IKKepsilon: a bridge between obesity and inflammation. 1973 22

Obesity is associated with chronic low-grade inflammation that negatively impacts insulin sensitivity. Here, we show that high-fat diet can increase NF-kappaB activation in mice, which leads to a sustained elevation in level of IkappaB kinase epsilon (IKKepsilon) in liver, adipocytes, and adipose tissue macrophages. IKKepsilon knockout mice are protected from high-fat diet-induced obesity, chronic inflammation in liver and fat, hepatic steatosis, and whole-body insulin resistance. These mice show increased energy expenditure and thermogenesis via enhanced expression of the uncoupling protein UCP1. They maintain insulin sensitivity in liver and fat, without activation of the proinflammatory JNK pathway. Gene expression analyses indicate that IKKepsilon knockout reduces expression of inflammatory cytokines, and changes expression of certain regulatory proteins and enzymes involved in glucose and lipid metabolism. Thus, IKKepsilon may represent an attractive therapeutic target for obesity, insulin resistance, diabetes, and other complications associated with these disorders.
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PMID:The protein kinase IKKepsilon regulates energy balance in obese mice. 2003 32

There is a tightly regulated interaction, which is well-conserved in evolution, between the metabolic and immune systems that is deranged in states of over- or under-nutrition. Obesity, an energy-rich condition, is characterized by the activation of an inflammatory process in metabolically active sites such as adipose tissue, liver and immune cells. The consequence of this response is a sharp increase in circulating levels of proinflammatory cytokines, adipokines and other inflammatory markers. Activation of the immune response in obesity is mediated by specific signaling pathways, with Jun N-terminal kinase and IkappaB kinase beta/nuclear factor kappa-light-chain-enhancer of activated B cells being the most well studied. It is known that the above events modify insulin signaling and result in the development of insulin resistance. The nutrient overload characterizing obesity is a metabolic stressor associated with intracellular organelle (e.g. the endoplasmic reticulum) stress. The exact characterization of the series of events and the mechanisms that integrate the inflammatory response with metabolic homeostasis at the cellular and systemic level is a very active research field. In this minireview, we discuss the signaling pathways and molecules associated with the development of obesity-induced inflammation, as well as the evidence that supports a critical role for the stress response in this process.
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PMID:Mechanisms of obesity and related pathology: linking immune responses to metabolic stress. 1975 72

The hormone resistin, which was originally shown to induce insulin resistance, has been implicated in the regulation of inflammatory processes, but the molecular mechanism underlying such regulation has not been clearly defined. The goal of our study was to determine whether the expression of COX-2 can be induced by resistin and what the potential signaling pathway involved in this process is. Compared with controls, resistin significantly upregulated COX-2 expression in RAW264.7 macrophage cells. Administration of anti-resistin antibody could significantly reduce this effect. Induction of COX-2 by resistin was also markedly reduced in the presence of either dominant negative mutant IkappaBalpha or PDTC, a pharmacological inhibitor of NF-kappaB. On the other hand, NF-kappaB subunit p65 was upregulated by resistin. Moreover, we found that transforming growth factor-beta-activated kinase 1 (TAK1), a mitogen-activated protein kinase kinase kinase (MAPKKK), could be activated in response to resistin. These results suggest that resistin enhances COX-2 expression in mouse macrophage cells in a TAK1-IKK-NF-kappaB-dependent manner and therefore plays a critical role in inflammatory processes.
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PMID:Resistin up-regulates COX-2 expression via TAK1-IKK-NF-kappaB signaling pathway. 1977 55

Resveratrol is a natural polyphenolic compound that activates nicotinamide adenosine dinucleotide-dependent deacetylase SIRT1. Resveratrol has recently been shown to exert potent antidiabetic actions when orally delivered to animal models of type 2 diabetes. However, the tissue(s) mediating these beneficial effects is unknown. Because SIRT1 is expressed in central nervous system (CNS) neurons known to control glucose and insulin homeostasis, we hypothesized that resveratrol antidiabetic effects are mediated by the brain. Here, we report that long-term intracerebroventricular infusion of resveratrol normalizes hyperglycemia and greatly improves hyperinsulinemia in diet-induced obese and diabetic mice. It is noteworthy that these effects are independent of changes in body weight, food intake, and circulating leptin levels. In addition, CNS resveratrol delivery improves hypothalamic nuclear factor-kappaB inflammatory signaling by reducing acetylated-RelA/p65 and total RelA/p65 protein contents, and inhibitor of nuclear factor-kappaB alpha and IkappaB kinase beta mRNA levels. Furthermore, this treatment leads to reduced hepatic phosphoenolpyruvate carboxykinase 1 mRNA and protein levels and ameliorates pyruvate-induced hyperglycemia in this mouse model of type 2 diabetes. Collectively, our results unveiled a previously unrecognized key role for the CNS in mediating the antidiabetic actions of resveratrol.
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PMID:Central administration of resveratrol improves diet-induced diabetes. 1981 63


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