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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Although glucocorticoid, as "gluco-" literally implies, plays an important role in maintaining the blood glucose level, excess of glucocorticoid production/action is known to cause impaired glucose tolerance and diabetes. Since 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), which converts inactive cortisone to active cortisol, is primarily expressed in the liver, an enhanced expression of the enzyme may increase the intracellular glucocorticoid level and thus increase the hepatic glucose production. In this study, we examined the effects of multiple humoral factors related to the
metabolic syndrome
on the transcriptional activity of 11beta-HSD1 gene in hepatocytes in vitro. We found that, among the factors examined, adipocyte-derived cytokines (adipokines), like TNFalpha and IL-1beta, potently stimulated the transcriptional activity of 11beta-HSD1 gene in human HuH7 cells. In contrast, only minimal effects of other humoral factors were observed when they were used alone. Interestingly, however, when applied in combination, they synergistically enhanced the transcriptional activity of 11beta-HSD1 gene. They also potentiated the effects of cytokines. Glucocorticoid receptor (GR)-dependent transcription was indeed increased even with an inactive glucocorticoid cortisone following TNFalpha pretreatment, indicating the enhanced intracellular conversion. Finally, PPARgamma/PPARalpha agonists, clinically used as anti-diabetic drugs, significantly inhibited the transcriptional activity of 11beta-HSD1. Altogether, our data strongly suggest that combination of the humoral factors related to the
metabolic syndrome
, including the adipokines, synergistically enhances the hepatic expression of 11beta-HSD1 gene and causes the intracellular Cushing state in the liver by increasing the intracellular glucocorticoid level. We assume that the observed synergistic effects of these factors on 11beta-HSD1 may, at least partly, explain the reason whereby accumulation of the multiple risk factors facilitates the derangement of glucose and lipid metabolism in the
metabolic syndrome
.
Mol
Cell Endocrinol 2008 Mar 26
PMID:Is the metabolic syndrome an intracellular Cushing state? Effects of multiple humoral factors on the transcriptional activity of the hepatic glucocorticoid-activating enzyme (11beta-hydroxysteroid dehydrogenase type 1) gene. 1831 35
Significant progress has been made in recent years in elucidating the molecular controls of cellular responses to DNA damage in mammalian cells. Much of our understanding of the mechanisms involved in cellular DNA damage response pathways has come from studies of human cancer susceptibility syndromes that are altered in DNA damage responses. Ataxia-telangiectasia mutated (ATM), the gene mutated in the disorder ataxia-telangiectasia, codes for a protein kinase that is a central mediator of responses to DNA double-strand breaks (DSB) in cells. Once activated, ATM phosphorylates numerous substrates in the cell that modulate the response of the cell to the DNA damage. We recently developed a novel system to create DNA DSBs at defined endogenous sites in the human genome and used this system to detect protein recruitment and loss at and around these breaks by chromatin immunoprecipitation. Results from this system showed the functional importance of ATM kinase activity and phosphorylation in the response to DSBs and supported a model in which ordered chromatin structure changes that occur after DNA breakage and that depend on functional NBS1 and ATM facilitate DNA DSB repair. Insights about these pathways provide us with opportunities to develop new approaches to benefit patients. Examples and opportunities for developing inhibitors that act as sensitizers to chemotherapy or radiation therapy or activators that could improve responses to cellular stresses, such as oxidative damage, are discussed. Relevant to the latter, we have shown benefits of an ATM activator in disease settings ranging from
metabolic syndrome
to cancer prevention.
Mol
Cancer Res 2008 Apr
PMID:DNA damage responses: mechanisms and roles in human disease: 2007 G.H.A. Clowes Memorial Award Lecture. 1840 32
Prague hypertriglyceridemic (HTG) rats represent a suitable model of
metabolic syndrome
. We have established the set of F(2) hybrids derived from HTG and Lewis progenitors to investigate the relationship between respective polymorphism(s) of Igf2 gene and blood pressure (BP) or other cardiovascular phenotypes. HTG rats had elevated systolic BP and plasma triglycerides but lower plasma cholesterol compared to Lewis rats of both genders. In males, there was higher mean arterial pressure, diastolic BP and relative heart weight in HTG than in Lewis rats. The results obtained in the total population of F(2) hybrids indicated strong segregation of Igf2 genotype with plasma triglycerides. There was no segregation of Igf2 genotype with any BP component except BP changes occurring after the blockade of either renin-angiotensin system (RAS) or NO synthase. When F(2) population was analyzed according to gender, male F(2) progeny homozygous for HTG Igf2 allele had significantly higher plasma triglycerides and greater BP changes after NO synthase blockade than those homozygous for Lewis allele. On the contrary, male F(2) progeny homozygous for HTG Igf2 allele had significantly lower plasma cholesterol and smaller BP changes after RAS blockade. PCR analysis of Igf2 gene by using of microsatelite D1Mgh22 has shown polymorphism between HTG and Lewis rats. Sequence analysis of cDNA revealed insertion of 14 nucleotides in HTG gene. In conclusion, polymorphism in Igf2 gene may be responsible for differences in lipid metabolism between HTG and Lewis rats. It remains to determine how these abnormalities could be involved in BP regulation by particular vasoactive systems.
Mol
Cell Biochem 2008 Jul
PMID:Abnormal Igf2 gene in Prague hereditary hypertriglyceridemic rats: its relation to blood pressure and plasma lipids. 1841 99
Metabolic syndrome
, which is caused by obesity, is now a global pandemic.
Metabolic syndrome
is an aggregation of hypertension, diabetes and dyslipidaemia. Insulin resistance is a key factor in the development of these components of
metabolic syndrome
. Concerning the mechanism for the development of hypertension in
metabolic syndrome
, the lack of insulin resistance in the kidney increases sodium reabsorption by hyperinsulinaemia, leading to sodium retention in the body, and resultant salt-sensitive hypertension. Moreover, hyperaldosteronism, which is caused by adipocyte-derived aldosterone-releasing factors, induces not only salt-sensitive hypertension, but also proteinuria in obese hypertensive rats. Salt loading markedly aggravates proteinuria and induces cardiac diastolic dysfunction in obese hypertensive rats, suggesting that salt and aldosterone exert unfavourable synergistic actions on the cardiovascular system, possibly through the overproduction of oxidative stress. In turn, reactive oxygen species (ROS), which are induced by adipokines such as tumour necrosis factor-alpha, non-esterified fatty acids, angiotensinogen etc., can activate the mineralocorticoid (MR) receptor, in an aldosterone-independent fashion. Therefore, aldosterone/MR activation plays a key role not only in the development of salt-sensitive hypertension, but also in cardiovascular injury in
metabolic syndrome
, possibly through its function as a feed-forward system.
J
Mol
Med (Berl) 2008 Jun
PMID:Aldosterone in salt-sensitive hypertension and metabolic syndrome. 1843 32
Metabolic syndrome
is associated with accelerated macrovascular and microvascular coronary disease, cardiomyopathy, and elevated inflammatory status. To determine whether
metabolic syndrome
-associated elevation of the inflammatory cytokine interleukin-18 (IL-18) in serum and cardiac tissue, and its potential sequelae could be attenuated pharmacologically, we studied fructose-fed rats. The fructose-fed rats exhibited increases in systolic blood pressure (SBP), body weight, heart weight, left ventricular weight, and blood insulin. Serum IL-18 levels in these rats were also elevated significantly. These changes were significantly different compared to those in control rats. Perivascular fibrosis around coronary arterioles was evident in the fructose-fed rats, accompanied by a paralleled increase in IL-18 by immunohistochemical analysis and real time polymerase chain reaction. Felodipine attenuated the increased levels in serum IL-18 and cardiac IL-18 mRNA as well as coronary perivascular fibrosis. Thus, augmented IL-18 in serum and cardiac tissue in
metabolic syndrome
may contribute to the coronary perivascular fibrosis; felodipine administration can attenuate the inflammatory and fibrosis process.
Mol
Med
PMID:Felodipine reduces cardiac expression of IL-18 and perivascular fibrosis in fructose-fed rats. 1850 4
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.
Int J
Mol
Med 2008 Jun
PMID:Association of genetic variants with atherothrombotic cerebral infarction in Japanese individuals with metabolic syndrome. 1850 75
Elevated levels of triglycerides and very low density lipoproteins (VLDL) are biochemical markers of
metabolic syndrome
and diabetes. VLDL from hypertriglyceridemic or diabetic patients increased the generation of plasminogen activator inhibitor-1 (PAI-1) from cultured vascular endothelial cells (EC). Susceptibility of VLDL to peroxidation was increased in diabetic patients. Heat shock factor-1 (HSF1) is implicated in the transcriptional regulation of PAI-1 induced by glycated low density lipoprotein (LDL). The present study examined the effects of oxidized VLDL (oxVLDL) on the expression of PAI-1 and HSF1 in cultured human EC and mouse embryo fibroblasts (MEF). OxVLDL modified by copper or iron ions increased the expression of PAI-1 and HSF1 in EC compared to VLDL or LDL. Butylated hydroxytulene inhibited oxVLDL-induced expression of PAI-1 and HSF1 in EC. OxVLDL increased the binding of HSF1 to PAI-1 promoter. Short interference RNA for HSF1 inhibited oxVLDL-induced PAI-1 expression in EC. OxVLDL stimulated the expression of PAI-1 from MEF of wild-type mice, but failed to increase PAI-1 expression in MEF of HSF1-knockout mice. The results indicate that oxVLDL increased PAI-1 expression, and HSF1 mediates the transcription of PAI-1 in cultured vascular EC or fibroblasts.
Mol
Cell Biochem 2008 Oct
PMID:Transcriptional regulation of plasminogen activator inhibitor-1 in vascular endothelial cells induced by oxidized very low density lipoproteins. 1859 60
Dysregulated hormonal, metabolic and neural signalling within and between organs can contribute to development of metabolic diseases including type 2 diabetes. Insulin-antagonistic effects of hormones, cytokines and excess metabolic substrates such as glucose and fatty acids may be exerted via common mechanisms involving for example reactive oxygen species (ROS) accumulation and associated inflammatory responses. Visceral adiposity is a central component of the
metabolic syndrome
and it is also strongly associated with insulin resistance. Both visceral obesity and insulin resistance are important risk factors for the development of type 2 diabetes. In the development of insulin resistance, it is likely that intra-abdominal adipose tissue plays a critical role in a complex endocrine and neural network involving several tissues. This review paper focuses on neuroendocrine 'stress' factors that target insulin-responsive tissues, in particular adipose tissue. We propose that there are common pathways by which dysregulation in different endocrine systems may contribute to the development of type 2 diabetes.
Mol
Cell Endocrinol 2009 Jan 15
PMID:Neuroendocrine mechanisms in insulin resistance. 1859 91
11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts inert 11keto-glucocorticoids to active 11beta-hydroxy forms, thereby amplifying intracellular glucocorticoid action. Up-regulation of 11beta-HSD1 in adipose tissue and liver is of pathogenic importance in
metabolic syndrome
. However, the mechanisms controlling 11beta-HSD1 transcription are poorly understood. Glucocorticoids themselves potently increase 11beta-HSD1 expression in many cells, providing a potential feed-forward system to pathology. We have investigated the molecular mechanisms by which glucocorticoids regulate transcription of 11beta-HSD1, exploiting an A549 cell model system in which endogenous 11beta-HSD1 is expressed and is induced by dexamethasone. We show that glucocorticoid induction of 11beta-HSD1 is indirect and requires new protein synthesis. A glucocorticoid-responsive region maps to between -196 and -88 with respect to the transcription start site. This region contains two binding sites for CCAAT/enhancer-binding protein (C/EBP) that together are essential for the glucocorticoid response and that bind predominantly C/EBPbeta, with C/EBPdelta present in a minority of the complexes. Both C/EBPbeta and C/EBPdelta are rapidly induced by glucocorticoids in A549 cells, but small interfering RNA-mediated knockdown shows that only C/EBPbeta reduction attenuates the glucocorticoid induction of 11beta-HSD1. Chromatin immunoprecipitation studies demonstrated increased binding of C/EBPbeta to the 11beta-HSD1 promoter in A549 cells after glucocorticoid treatment. A similar mechanism may apply in adipose tissue in vivo where increased C/EBPbeta mRNA levels after glucocorticoid treatment were associated with increased 11beta-HSD1 expression. C/EBPbeta is a key mediator of metabolic and inflammatory signaling. Positive regulation of 11beta-HSD1 by C/EBPbeta may link amplification of glucocorticoid action with metabolic and inflammatory pathways and may represent an endogenous innate host-defense mechanism.
Mol
Endocrinol 2008 Sep
PMID:Glucocorticoid regulation of the promoter of 11beta-hydroxysteroid dehydrogenase type 1 is indirect and requires CCAAT/enhancer-binding protein-beta. 1861 97
Selective thyroid hormone receptor subtype-beta (TRbeta) agonists have received attention as potential treatments for hypercholesterolemia and obesity, but have received less attention as treatments for diabetes, partly because this condition is not improved in thyroid hormone excess states. The TRbeta selective agonist KB-141 induces 5-10% increases in metabolic rate and lowering of plasma cholesterol levels without tachycardia in lean rats, unlike the major active thyroid hormone, T3. In the current study, we determined whether KB-141 promotes weight loss in obese animals and whether it exhibits anti-diabetogenic effects. Body weight, adiposity (DEXA), and lipid levels were examined following p.o. administration of KB-141 to obese Zucker fa/fa rats at 0.00547-0.547 mg/kg/day for 21 days, and in ob/ob mice at 0.5mg/kg/day KB-141 for 7 days. In rats, KB-141 reduced body weight by 6 and 8%, respectively, at 0.167 and 0.0547 mg/kg/day without tachycardia and adiposity was reduced at 0.167 mg/kg/day (5-6%). In ob/ob mice, KB-141 lowered serum cholesterol (35%), triacylglycerols (35%) and both serum and hepatic free fatty acids (18-20%) without tachycardia. Treatment of ob/ob mice with KB-141 (0.0547 or 0.328 mg/kg/day over 2 weeks) improved glucose tolerance and insulin sensitivity in a dose-dependent manner with no effect on heart rate. Thus, KB-141 elicits anti-obesity, lipid lowering and anti-diabetic effects without tachycardia suggesting that selective TRbeta activation may be useful strategy to attenuate features of the
metabolic syndrome
.
J Steroid Biochem
Mol
Biol 2008 Sep
PMID:Anti-obesity, anti-diabetic, and lipid lowering effects of the thyroid receptor beta subtype selective agonist KB-141. 1862 Nov 27
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