Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-6 (IL-6) is a pleiotropic cytokine involved in the pathophysiology of various human diseases such as type 2 diabetes and obesity. IL-6 signals via a heterodimeric receptor complex consisting of a soluble IL-6 alpha-subunit (IL-6 receptor [IL6R]) and a signal transducing subunit (gp130). The IL6R gene maps to an important candidate locus for type 2 diabetes on chromosome 1q21. An Asp358Ala polymorphism of the IL6R has been reported to associate with obesity in Pima Indians. We investigated the Asp358Ala polymorphism in relation to type 2 diabetes, obesity, and other pre-diabetic quantitative traits among Danish whites. By applying a recessive genetic model in a case-control study of 1,349 type 2 diabetic patients and 4,596 glucose-tolerant control subjects, we found a significant difference in genotype distribution (P = 0.008) and in allele frequency (Ala-allele 38.3% [95% CI 36.5-40.1] in diabetic subjects vs. 41.2% [40.2-42.2] in control subjects; P = 0.007). The odds ratio for the Asp/Asp carriers versus Ala/Ala carriers was 1.38 (1.09-1.71). Among 4,251 middle-aged glucose-tolerant subjects, the Asp358Ala polymorphism was not associated with estimates of obesity, post-oral glucose tolerance test serum insulin release, or the homeostasis model assessment of insulin resistance index. In conclusion, the Asp358Ala polymorphism of the IL6R associates with type 2 diabetes in Danish whites.
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PMID:Variation in the interleukin-6 receptor gene associates with type 2 diabetes in Danish whites. 1556 70

The agouti-related protein (AGRP) is an endogenous antagonist of the centrally expressed melanocortin receptors. The melanocortin-4 receptor (MC4R) is involved in energy homeostasis, food intake, sexual function, and obesity. The endogenous hAGRP protein is 132 amino acids in length, possesses five disulfide bridges at the C-terminus of the molecule, and is expressed in the hypothalamus of the brain. We have previously reported that a monocyclic hAGRP(103-122) peptide is an antagonist at the melanocortin receptors expressed in the brain. Stereochemical inversion from the endogenous l- to d-isomers of single or multiple amino acid modifications in this monocyclic truncated hAGRP sequence resulted in molecules that are converted from melanocortin receptor antagonists into melanocortin receptor agonists. The Asp-Pro-Ala-Ala-Thr-Ala-Tyr-cyclo[Cys-Arg-DPhe-DPhe-Asn-Ala-Phe-Cys]-Tyr-Ala-Arg-Lys-Leu peptide resulted in a 60 nM melanocortin-1 receptor agonist that is 100-fold selective versus the mMC4R, 1000-fold selective versus the mMC3R, and ca. 180-fold selective versus the mMC5R. In attempts to identify putative ligand-receptor interactions that may be participating in the agonist induced stimulation of the MC4R, selected ligands were docked into a homology molecular model of the mMC4R. These modeling studies have putatively identified hAGRP ligand DArg111-mMC4RAsn115 (TM3) and the hAGRP DPhe113-mMC4RPhe176 (TM4) interactions as important for agonist activity.
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PMID:Stereochemical studies of the monocyclic agouti-related protein (103-122) Arg-Phe-Phe residues: conversion of a melanocortin-4 receptor antagonist into an agonist and results in the discovery of a potent and selective melanocortin-1 agonist. 1561 19

TNF-alpha is a mediator of insulin resistance in sepsis, obesity, and type 2 diabetes and is known to impair insulin signaling in adipocytes. Akt (protein kinase B) is a crucial signaling mediator for insulin. In the present study we examined the posttranslational mechanisms by which short-term (<6-h) exposure of 3T3-L1 adipocytes to TNF-alpha decreases Akt levels. TNF-alpha treatment both increased the ubiquitination of Akt and decreased its protein level. The decrease in protein was associated with the presence of an (immunoreactive) Akt fragment after TNF-alpha treatment, indicative of Akt cleavage. The broad-spectrum caspase inhibitor t-butoxycarbonyl-Asp(O-Me)-fluoromethyl ketone markedly suppressed these effects of TNF-alpha. The caspase-6 inhibitor Z-Val-Glu(OMe)-Ile-Asp(OMe)-CH(2)F potently suppressed Akt ubiquitination, degradation, and fragment formation, whereas the proteasome inhibitor Z-Leu-Leu-Leu-CHO modestly attenuated the decline in Akt levels. Exposure to TNF-alpha also enhanced the association of Akt with an E3 ligase activity. Adipocytes preexposed to TNF-alpha for 5 h and then stimulated with insulin for 30 min exhibited decreased levels of Akt, phosphorylated Akt, as well as phosphorylated Mdm2, which is a known direct substrate of Akt, and glucose uptake. Caspase inhibition attenuated these inhibitory effects of TNF-alpha. Collectively, our results suggest that TNF-alpha induces the caspase-dependent degradation of Akt via the cleavage and ubiquitination of Akt, which results in its degradation through the 26S proteasome. Furthermore, the caspase- and proteasome-mediated degradation of Akt due to TNF-alpha exposure leads to impaired Akt-dependent insulin signaling in adipocytes. These findings expand the mechanism by which TNF-alpha impairs insulin signaling.
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PMID:Tumor necrosis factor-{alpha} decreases Akt protein levels in 3T3-L1 adipocytes via the caspase-dependent ubiquitination of Akt. 1574 49

Adipogenesis plays a central role in obesity development. The processes of adipogenesis include migration, adhesion, proliferation and survival of preadipocytes and differentiation to mature adipocytes. Many of these biological functions are related to integrins. Here, we found that snake venom-derived arginine-glycine-aspartic acid (RGD)-containing disintegrin inhibited adipogenesis. Rhodostomin but not rhodostomin RGD mutants (RGE-Rn and AKGDWN-Rn) caused the detachment of primary cultured preadipocyte. Furthermore, rhodostomin also inhibited focal adhesion of preadipocyte, including the inhibition of the expression of focal adhesion kinase (FAK) and FAK phosphorylation, assembly of vinculin and reorganization of actin cytoskeleton. Cell viability of preadipocytes was decreased after rhodostomin treatment in a concentration-dependent manner. The results of flow cytometric analysis showed that rhodostomin induced cell apoptosis. In addition, chromatin condensation was observed in DAPI staining. The increase of Bax expression and activation of capsase-3 was detected following rhodostomin treatment. Addition of dexamethasone, IBMX and insulin induced differentiation of preadipocytes into mature adipocytes and treatment of cells with rhodostomin during the initial 3 days showed less mature adipocytes following 9-10 days of differentiating period. The triglyceride content and gene expression of peroxisome proliferators-activated receptor gamma (PPARgamma) and leptin also decreased in response to the treatment of rhodostomin. These results suggest that disintegrin inhibits processes of adipogenesis and may be developed to treat obesity.
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PMID:Inhibition of adipogenesis by RGD-dependent disintegrin. 1619 20

Several hormones that regulate nutritional status also impact on bone metabolism. Preptin is a recently isolated 34-amino acid peptide hormone that is cosecreted with insulin and amylin from the pancreatic beta-cells. Preptin corresponds to Asp(69)-Leu(102) of pro-IGF-II. Increased circulating levels of a pro-IGF-II peptide complexed with IGF-binding protein-2 have been implicated in the high bone mass phenotype observed in patients with chronic hepatitis C infection. We have assessed preptin's activities on bone. Preptin dose-dependently stimulated the proliferation (cell number and DNA synthesis) of primary fetal rat osteoblasts and osteoblast-like cell lines at periphysiological concentrations (>10(-11) M). In addition, thymidine incorporation was stimulated in murine neonatal calvarial organ culture, likely reflecting the proliferation of cells from the osteoblast lineage. Preptin did not affect bone resorption in this model. Preptin induced phosphorylation of p42/p44 MAP kinases in osteoblastic cells in a dose-dependent manner (10(-8)-10(-10) M), and its proliferative effects on primary osteoblasts were blocked by MAP kinase kinase inhibitors. Preptin also reduced osteoblast apoptosis induced by serum deprivation, reducing the number of apoptotic cells by >20%. In vivo administration of preptin increased bone area and mineralizing surface in adult mice. These data demonstrate that preptin, which is cosecreted from the pancreatic beta-cell with amylin and insulin, is anabolic to bone and may contribute to the preservation of bone mass observed in hyperinsulinemic states such as obesity.
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PMID:Preptin, another peptide product of the pancreatic beta-cell, is osteogenic in vitro and in vivo. 1691 56

Leptin, an adipocytokine encoded by an obesity gene and expressed in adipose tissue, affects feeding behavior, thermogenesis, and neuroendocrine status via leptin receptors distributed in the brain, especially in the hypothalamus. Leptin may also modulate the synaptic plasticity and behavioral performance related to learning and memory since: leptin receptors are found in the hippocampus, and both leptin and its receptor share structural and functional similarities with the interleukin-6 family of cytokines that modulate long-term potentiation (LTP) in the hippocampus. We therefore examined the effect of leptin on (1) behavioral performance in emotional and spatial learning tasks, (2) LTP at Schaffer collateral-CA1 synapses, (3) presynaptic and postsynaptic activities in hippocampal CA1 neurons, (4) the intracellular Ca(2+) concentration ([Ca(2+)](i)) in CA1 neurons, and (5) the activity of Ca(2+)/calmodulin protein kinase II (CaMK II) in the hippocampal CA1 tissue that exhibits LTP. Intravenous injection of 5 and/or 50mug/kg, but not of 500mug/kg leptin, facilitated behavioral performance in passive avoidance and Morris water-maze tasks. Bath application of 10(-12)M leptin in slice experiments enhanced LTP and increased the presynaptic transmitter release, whereas 10(-10)M leptin suppressed LTP and reduced the postsynaptic receptor sensitivity to N-methyl-d-aspartic acid. The increase in the [Ca(2+)](i) induced by 10(-10)M leptin was two times greater than that induced by 10(-12)M leptin. In addition, the facilitation (10(-12)M) and suppression (10(-10)M) of LTP by leptin was closely associated with an increase and decrease in Ca(2+)-independent activity of CaMK II. Our results show that leptin not only affects hypothalamic functions (such as feeding, thermogenesis, and neuroendocrine status), but also modulates higher nervous functions, such as the behavioral performance related to learning and memory and hippocampal synaptic plasticity.
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PMID:Leptin facilitates learning and memory performance and enhances hippocampal CA1 long-term potentiation and CaMK II phosphorylation in rats. 1691 28

The paleopathological study of 31 Italian Renaissance mummies from the Basilica of S. Domenico Maggiore in Naples has allowed us to perform about 20 diagnoses, of which 5 concern infectious (smallpox, hepatitis, condyloma, syphilis and pneumonia), 3 metabolic (obesity, atherosclerosis, gallstones), I articular (DISH) and 2 neoplastic (colon adenocarcinoma and skin carcinoma) diseases. The mummy of an anonymous child, dated back to the 16th century (14C: 1569 +/- 60), presented a diffuse vesiculopustular exanthema. Macroscopic aspects and regional distribution suggested smallpox, while EM revealed many egg-shaped, virus-like particles (250 x 50 nm), with a central dense core. Following incubation with anti-smallpox virus antiserum and protein A-gold complex immunostaining, the particles resulted completely covered with protein A-gold. These results clearly show that this Neapolitan child died of a severe form of smallpox some four centuries ago. The mummy of Maria d'Aragona, Marquise of Vasto (1503-1568), revealed on the left arm an oval, cutaneous ulcer (15 x l0 mm) with linen dressing. Indirect immunofluorescence with anti-treponema pallidum antibody identified a large number of filaments with the morphological characteristics of fluorescent treponemes. Electron microscopy evidenced typical spirochetes, with axial fibril. These findings clearly demonstrate a treponemal, probably venereal, infection. Further examination of the mummy showed a large peduncolate arborescent neoformation (2 x 7 mm) of the right inguinal region, which was rehydrated and submitted to histology by hematoxylineosin, Van Gieson and Masson's trichromic staining. Light microscopy evidenced an exophytic, papillary skin lesion, with typical connective axis and pronounced parakeratosis. These macroscopic and histological aspects seemed peculiar of condyloma acuminatum, a papillomavirus-induced squamous lesion also called "venereal wart". Molecular study revealed the presence of HPV 18, a virus with high oncogenic potential. Automated sequencing of several clones revealed 100% similarity sequences of both HPV 18 and JC9813 DNA, a putative novel HPV with low oncogenic potential. This study represents the first molecular diagnosis of HPV in mummies and could pave the way for further research about the secular evolution of these viruses, very important in human oncology. The buccal surfaces of the teeth of Isabella d'Aragona, duchess of Milan ((1470-1524), covered by a black patina with high mercury levels, have been intensively and intentionally abraded. The black patina can be attributed to chronic mercury intoxication, used therapeutically in the treatment of syphilis. The mummy of Ferrante I d'Aragona, King of Naples (1431-1494), revealed an adenocarcinoma extensively infiltrating the muscles of the small pelvis. A molecular study of the neoplastic tissue evidenced a typical mutation of the K-ras gene codon 12: the normal sequence GGT (glycine) was altered into GAT (aspartic acid). At present this genetic change is the most frequent mutation of the K-ras gene in sporadic colorectal cancer. The alimentary "environment" of the Neapolitan court of the XV century, with its abundance of natural alimentary alkylating agents, well explains this acquired mutation. These and other diseases as, for example, a case of cirrhosis, some cases of anthracosis and other peculiar traumatic conditions, such as a mortal stab-wound, can elucidate the pathocenosis of this wealthy classes of the Italian Renaissance.
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PMID:[The Aragonese mummies of the Basilica of Saint Domenico Maggiore in Naples]. 1817 25

To understand the molecular mechanisms underlying the development of dyslipidemia and lipodystrophy that occurs after administration of aspartic acid protease inhibitors, we examined transcriptional profiles using cDNA microarrays in 3T3-L1 adipocytes exposed to 10 micromol/l ritonavir for 2-21 days. The expression levels of approximately 12,000 transcripts were assessed using the MgU74Av2 mouse microarray chip. Ritonavir altered gene expression of inflammatory cytokines, stress response genes localized to endoplasmic reticulum, oxidative stress genes, apoptosis-related genes, and expression of genes involved in cell adhesion and extracellular matrix remodeling. Microarray analysis also identified a novel gene downregulated by ritonavir, Cidea, whose expression levels may affect free-fatty acid metabolism. These changes suggest a unique, stress-related pattern in adipocytes induced by chronic exposure to the protease inhibitor, ritonavir.
Obesity (Silver Spring) 2008 Oct
PMID:Effects of ritonavir on adipocyte gene expression: evidence for a stress-related response. 1871 45

In the N-end rule pathway of protein degradation, the destabilizing activity of N-terminal Asp, Glu or (oxidized) Cys residues requires their conjugation to Arg, which is recognized directly by pathway's ubiquitin ligases. N-terminal arginylation is mediated by the Ate1 arginyltransferase, whose physiological substrates include the Rgs4, Rgs5 and Rgs16 regulators of G proteins. Here, we employed the Cre-lox technique to uncover new physiological functions of N-terminal arginylation in adult mice. We show that postnatal deletion of mouse Ate1 (its unconditional deletion is embryonic lethal) causes a rapid decrease of body weight and results in early death of approximately 15% of Ate1-deficient mice. Despite being hyperphagic, the surviving Ate1-deficient mice contain little visceral fat. They also exhibit an increased metabolic rate, ectopic induction of the Ucp1 uncoupling protein in white fat, and are resistant to diet-induced obesity. In addition, Ate1-deficient mice have enlarged brains, an enhanced startle response, are strikingly hyperkinetic, and are prone to seizures and kyphosis. Ate1-deficient males are also infertile, owing to defects in Ate1(-/-) spermatocytes. The remarkably broad range of specific biological processes that are shown here to be perturbed by the loss of N-terminal arginylation will make possible the dissection of regulatory circuits that involve Ate1 and either its known substrates, such as Rgs4, Rgs5 and Rgs16, or those currently unknown.
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PMID:Ablation of arginylation in the mouse N-end rule pathway: loss of fat, higher metabolic rate, damaged spermatogenesis, and neurological perturbations. 1991 79

The cationic, alpha-helical frog skin antimicrobial peptide B2RP (brevinin-2-related peptide) shows sequence similarity to antimicrobial peptides belonging to the brevinin-2 family, but lacks the C-terminal cyclic heptapeptide domain (Cys-Lys-Xaa (4)-Cys). Synthetic B2RP produced a significant (p<0.05) stimulation of insulin release (148% of basal rate at a concentration of 1 muM with a maximum response of 222% of basal rate at a concentration of 3 muM) from BRIN-BD11 clonal beta-cells without increasing the release of the cytosolic enzyme, lactate dehydrogenase. Increasing cationicity of B2RP while maintaining amphipathicity by the substitution Asp (4) --> Lys enhanced the insulin-releasing potency (137% of basal rate at a concentration of 0.3 muM; p<0.05) with no stimulation of lactate dehydrogenase release. In contrast, the L18K, and D4K, L18K analogues were toxic to the cells, and the K16A analogue, with increased amphipathicity and hydrophobicity, showed reduced potency. Administration of [D4K]B2RP (100 nmol/kg body weight) to mice fed a high fat diet to induce obesity and insulin-resistance significantly (p<0.05) enhanced insulin release and improved glucose tolerance during the 60-minute period following an intraperitoneal glucose load (18 mmol/kg body weight). B2RP shows potential for development into an agent for the treatment of type 2 diabetes.
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PMID:Brevinin-2-related peptide and its [D4K] analogue stimulate insulin release in vitro and improve glucose tolerance in mice fed a high fat diet. 2049 6


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