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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor regulating an array of diverse functions in a variety of cell types including regulation of genes associated with growth and differentiation. Its most notable function is to regulate development of adipose tissue, which involves coordinating expression of many hundreds of genes responsible for establishment of the mature adipocyte phenotype. Our recent studies have demonstrated a role for MEK/ERK signaling and CCAAT/enhancer binding proteins (C/EBP)beta in regulating expression of PPARgamma during adipogenesis. Furthermore, we have shown that cAMP-dependent signaling along with C/EBPbeta leads to the stimulation of PPARgamma activity by mechanisms that probably involve production of PPARgamma ligands. Additionally, we have recently demonstrated that phosphorylation of C/EBPbeta at a consensus ERK/GSK3 site is required for the PPARgamma-associated expression of adiponectin during the terminal stages of adipogenesis. GSK3beta also influences PPARgamma activity by regulating the turnover and subcellular localization of beta-catenin, a potent transcriptional activator of Wnt signaling. In fact, we have recently shown a crosstalk between PPARgamma and beta-catenin signaling. Specifically, activation of PPARgamma induces the degradation of beta-catenin during preadipocyte differentiation by mechanisms that require GSK3beta and the proteasome. In contrast, expression of a GSK3beta-phosphorylation-defective beta-catenin renders beta-catenin resistant to the degradatory action of PPARgamma. Interestingly, expression of the mutant beta-catenin blocks expression of adiponectin and C/EBPalpha in response to the activation of PPARgamma.
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PMID:Regulation of PPARgamma activity during adipogenesis. 1571 76

The role of two adipocytokines, adiponectin and leptin, in Taiwanese breast cancer patients remains to be determined. In this study, we analyzed the correlations between the serum levels of adiponectin and leptin and the various clinicopathological parameters in 100 newly diagnosed, histologically confirmed breast cancer patients and 100 controls. We found serum levels were decreased significantly for adiponectin in the breast cancer patients, in comparison to controls (Student t-test, P=0.003), while serum levels were increased significantly for leptin in the breast cancer patients in comparison to controls (Student t-test, P=0.025). Leptin/adiponectin (L/A ratio) were increased significantly in the breast cancer patients, in comparison to controls (Student t-test, P=0.009). Among the clinicopathological parameters, estrogen receptor, progesterone receptor, HER2/neu, lymph node metastasis, tumor stage, and tumor grade all showed no effect on the serum levels of adiponectin and leptin. BMI was negatively and positively correlated to serum adiponectin and leptin levels, respectively (Spearman's correlation, r=-0.333 and 0.323, respectively; P<0.001 for both). Intriguingly, serum L/A ratio disclosed a positive correlation to tumor size (r=0.21, P=0.036). In summary, our results suggest that low serum adiponectin levels and high serum leptin levels are associated with an increased risk for breast cancer. Also, independent of the effect of BMI, the increased serum ratio of L/A may indicate the presence of aggressive breast cancers.
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PMID:Serum adiponectin and leptin levels in Taiwanese breast cancer patients. 1601 38

Adiponectin is an antiatherogenic adipokine that inhibits inflammation by mechanisms that are not completely understood. We explored the effect of adiponectin on endothelial synthesis of interleukin-8 (IL-8), a pro-inflammatory chemokine that plays a role in atherogenesis. Adiponectin decreased the secretion of IL-8 from human aortic endothelial cells (HAEC) stimulated with tumor necrosis factor-alpha (TNF-alpha). Adiponectin also inhibited IL-8 mRNA expression induced by TNF-alpha. Phosphorylation of IkappaB-alpha was decreased by adiponectin, but phosphorylation of ERK, SAPK/JNK, and p38MAPK were unaffected. Adiponectin increased intra-cellular cAMP levels in HAEC in a dose-dependent manner; PKA activity was also increased. The inhibitory effect of adiponectin on TNF-alpha-induced IL-8 synthesis was inhibited by pretreatment with Rp-cAMP, a PKA inhibitor. These observations suggest that adiponectin inhibits IL-8 synthesis through inhibition of a PKA dependent NF-kappaB signaling pathway. We also showed that adiponectin enhances Akt phosphorylation. The inhibitory effect of adiponectin on TNF-alpha-induced IL-8 synthesis was abrogated in part by pretreatment with the PI3 kinase inhibitor LY294002 or by Akt siRNA transfection, suggesting that Akt activation might inhibit IL-8 synthesis induced by TNF-alpha. We conclude that inhibition of NF-kappaB and activation of Akt phosphorylation may mediate adiponectin inhibition of atherosclerosis.
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PMID:Adiponectin inhibits endothelial synthesis of interleukin-8. 1633 93

Type 2 diabetes is a heterogeneous disease characterized by hyperglycemia and insulin resistance in peripheral tissues such as adipose tissue and skeletal muscle. This review focuses on obesity as one of the major environmental factors contributing to the development of diabetes. It has become evident that adipose tissue represents an active secretory organ capable of releasing a variety of cytokines such as TNFalpha, IL-6, adiponectin and other still unknown factors that might constitute the missing link between adipose tissue and insulin resistance. In fact, adipocyte-derived factors are significantly increased in obesity and represent good predictors of the development of type 2 diabetes. The negative crosstalk between adipocytes and skeletal muscle cells leads to disturbances in muscle cell insulin signalling and insulin resistance involving major pathways in inflammation, cellular stress and mitogenesis. Positive regulators of insulin sensitivity include the adipocyte hormone adiponectin and inhibitors of inflammatory pathways such as JNK-, IKK- and ERK-inhibitors. In summary, a better knowledge of intracellular and intercellular mechanisms by which adipose tissue affects skeletal muscle cell physiology may help to develop new strategies for diabetes treatment.
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PMID:Pathways leading to muscle insulin resistance--the muscle--fat connection. 1693 52

The purpose of this study was to measure changes in plasma adiponectin (ApN) over 24 months of exercise intervention in middle age adults with a predisposition to metabolic syndrome and to determine if changes in ApN were more affected by physical activity or physical fitness. Thirty-six subjects completed a 24 months home-based exercise program (cycling>or=three times per week, >or=45 min/session at 50-65% of VO2peak). Body composition, blood samples, and physical fitness were studied at baseline and after 12 and 24 months of participation in the study. The prescribed physical activity was monitored via self-reported exercise diary to determine MET levels, hours, and exercise compliance. Two-tailed repeated measures ANOVA and Spearman Rank Correlation Coefficients were used to detect significant differences and associations between the variables. ApN increased significantly (P<0.05) after 12 months in males (n=17; 5.3+/-1.9-7.0+/-3.0 microg ml-1) but not in females (n=9; 8.6+/-3.8-11.5+/-4.0 microg ml-1). The net change in ApN over 24 months was significantly correlated to the net change in VO2peak (physical fitness) (r=0.66; P<0.001), whereas exercise intensity was negatively correlated to DeltaApN over 12 months (r=-0.4; P<or=0.04) and 24 months (r=-0.45; P<or=0.02). Based on our results, an improvement in cardiorespiratory fitness of 15% increased plasma ApN concentration. Our findings suggest that moderate physical activity performed over many months induces positive changes in the plasma ApN concentration in adults with a predisposition to metabolic syndrome.
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PMID:The effect of physical activity and physical fitness on plasma adiponectin in adults with predisposition to metabolic syndrome. 1704 82

In this study, we investigate the ability of reversine to stimulate adipocyte differentiation and its effect on cellular signaling pathways associated with adipocyte differentiation. Our data show that reversine treatment of 3T3-L1 cells under differentiation conditions synergistically enhances adipocyte differentiation and the expression of adipogenic marker genes such as aP2, PPAR-gamma, resistin, C/EBPalpha, and adiponectin. In parallel, reversine treatment leads to a selective downregulation of Akt and p70(s6k) signaling pathways, but not the ERK pathway. Furthermore, reversine stimulation of adipocyte differentiation seems to be quite different from troglitazone's action, because reversine treatment does not induce the transcriptional activation of PPAR-gamma and troglitazone does not affect the Akt and p70(s6k) signaling pathways. Taken together, our data clearly demonstrate the ability of reversine to stimulate adipocyte differentiation, which is independent of the Akt and p70(s6k) signaling pathways.
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PMID:Reversine stimulates adipocyte differentiation and downregulates Akt and p70(s6k) signaling pathways in 3T3-L1 cells. 1749 Jun 11

Differentiation of preadipocytes into functional adipocytes depends on early proliferative events (mitotic clonal expansion) and extracellular matrix interactions. We report that discoidin domain receptor (DDR) 2, a novel adhesion receptor, is expressed in 3T3-L1 preadipocytes and is downregulated during the early phase of adipogenesis. DDR2 overexpression (DDR2-L1 preadipocytes) reduced subconfluent proliferation by 56% (p<0.001) and insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 by 34% (p<0.05). The mitotic clonal expansion phase of differentiating confluent DDR2-L1 preadipocytes was impaired by approximately 25% (p<0.05). Although induction of peroxisome proliferator-activated receptor gamma, fatty acid synthase, and adiponectin was not altered, the resulting adipocytes were 55% larger (p<0.05), and contained 66% more triacylglycerol (p<0.01). The induction of CCAAT/enhancer binding protein alpha was reduced by 37% (p<0.05), correlating with a similar reduction in insulin-stimulated IRS-1 tyrosine phosphorylation and glucose transport in DDR2-L1 adipocytes (decreases of 22% and 27%, respectively; p<0.05 for both). Our data show that DDR2 is expressed in adipose cells and that its overexpression leads to insulin resistance.
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PMID:Discoidin domain receptor 2 impairs insulin-stimulated insulin receptor substrate-1 tyrosine phosphorylation and glucose uptake in 3T3-L1 adipocytes. 1771 22

Adiponectin exerts an insulin-sensitizing effect, improving insulin action in peripheral tissues and restraining insulin resistance. Here, we explore the hypothesis that adiponectin can reproduce some of the actions of insulin/leptin in the hypothalamus. The presence of AdipoR1 and AdipoR2 was mapped to the arcuate and lateral hypothalamic nuclei. Icv adiponectin reduced food intake, which was accompanied by activation/engagement of IRS1/2, ERK, Akt, FOXO1, JAK2 and STAT3. All these actions were dependent on AdipoR1, since inhibition of this receptor, and not of AdipoR2, completely reversed the effects described above. Thus, adiponectin acts in the hypothalamus, activating elements of the canonical insulin and leptin signaling pathways and promoting reduction of food intake.
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PMID:AdipoR1 mediates the anorexigenic and insulin/leptin-like actions of adiponectin in the hypothalamus. 1839 28

Habitual physical activity and chronic exercise may positively influence circulating cytokines in youth as in adults. The purpose of this study was to determine if adolescents reporting higher amounts of physical activity had a better cytokine profile independent of weight status. We compared the concentrations of cytokines in highly active (n = 60) and less active adolescents (n = 60) of different weight status [normal weight (BMI < 75th percentile), and overweight (BMI > 95th percentile)]. Vigorous physical activity (VPA) was obtained through a questionnaire and included activities with a MET level of > or =6. Adiponectin, resistin, TNF-alpha and IL-6 were measured in fasting plasma samples. Anovas indicated that girls with high VPA had higher adiponectin than girls with low VPA (P < 0.05), but similar resistin, TNF-alpha and IL-6 concentrations (P > 0.05). Boys with high VPA had only a trend to lower resistin than those with low VPA (P = 0.052). Differences between VPA groups were independent of weight status. In adolescents, higher amounts of accumulated habitual VPA may improve some cytokines, reducing the risk of inflammation associated with increased adiposity and insulin resistance. The effect of physical activity appears to be independent of weight status.
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PMID:Vigorous physical activity and cytokines in adolescents. 1841 17

Metabolic syndrome is a risk factor for cardiovascular disease. The aim of the present study was to identify genetic variants that confer susceptibility to atherothrombotic cerebral infarction among individuals with metabolic syndrome in order to allow prediction of genetic risk for this condition. The study population comprised 1284 unrelated Japanese individuals with metabolic syndrome, including 313 subjects with atherothrombotic cerebral infarction and 971 controls. The genotypes for 296 polymorphisms of 202 candidate genes were determined with a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. The Chi-square test, multivariable logistic regression analysis with adjustment for age, sex, body mass index, and the prevalence of hypertension, hypercholesterolemia, and diabetes mellitus, as well as a stepwise forward selection procedure revealed that the 2445G-->A (Ala54Thr) polymorphism (rs1799883) of FABP2, the -108/3G-->4G polymorphism of IPF1 (S82168), the A-->G (Thr94Ala) polymorphism (rs2241883) of FABP1, the G-->A (Asp2213Asn) polymorphism (rs529038) of ROS1, the -11377C-->G polymorphism (rs266729) of ADIPOQ, the 162A-->C polymorphism (rs4769055) of ALOX5AP, the -786T-->C polymorphism (rs2070744) of NOS3, and the 3279C-->T polymorphism (rs7291467) of LGALS2 were associated (P<0.05) with the prevalence of atherothrombotic cerebral infarction. Among these polymorphisms, the 2445G-->A (Ala54Thr) polymorphism of FABP2 was most significantly associated with this condition. Our results suggest that FABP2, IPF1, FABP1, ROS1, ADIPOQ, ALOX5AP, NOS3, and LGALS2 are susceptibility loci for atherothrombotic cerebral infarction among Japanese individuals with metabolic syndrome. Genotypes for these polymorphisms, especially for the 2445G-->A (Ala54Thr) polymorphism of FABP2, may prove informative for the prediction of genetic risk for atherothrombotic cerebral infarction among such individuals.
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PMID:Association of genetic variants with atherothrombotic cerebral infarction in Japanese individuals with metabolic syndrome. 1850 75


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