Melanocortin receptor 4 deficiency affects body weight regulation, grooming behavior, and substrate preference in the rat

NARCIS (Netherlands)

Mul, J.D.; van Boxtel, R.; Bergen, D.J.; Brans, M.A.; Brakkee, J.H.; Toonen, P.W.; Garner, K.M.; Adan, R.A.; Cuppen, E.

2012-01-01

Obesity is caused by an imbalance between energy intake and expenditure and has become a major health-care problem in western society. The central melanocortin system plays a crucial role in the regulation of feeding and energy expenditure, and functional loss of melanocortin receptor 4 (MC4R) is

Ac-Trp-DPhe(p-I)-Arg-Trp-NH2, a 250-Fold Selective Melanocortin-4 Receptor (MC4R) Antagonist over the Melanocortin-3 Receptor (MC3R), Affects Energy Homeostasis in Male and Female Mice Differently.

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Lensing, Cody J; Adank, Danielle N; Doering, Skye R; Wilber, Stacey L; Andreasen, Amy; Schaub, Jay W; Xiang, Zhimin; Haskell-Luevano, Carrie

2016-09-21

The melanocortin-4 receptor (MC4R) has been indicated as a therapeutic target for metabolic disorders such as anorexia, cachexia, and obesity. The current study investigates the in vivo effects on energy homeostasis of a 15 nM MC4R antagonist SKY2-23-7, Ac-Trp-DPhe(p-I)-Arg-Trp-NH2, that is a 3700 nM melanocortin-3 receptor (MC3R) antagonist with minimal MC3R and MC4R agonist activity. When monitoring both male and female mice in TSE metabolic cages, sex-specific responses were observed in food intake, respiratory exchange ratio (RER), and energy expenditure. A 7.5 nmol dose of SKY2-23-7 increased food intake, increased RER, and trended toward decreasing energy expenditure in male mice. However, this compound had minimal effect on female mice's food intake and RER at the 7.5 nmol dose. A 2.5 nmol dose of SKY2-23-7 significantly increased female food intake, RER, and energy expenditure while having a minimal effect on male mice at this dose. The observed sex differences of SKY2-23-7 administration result in the discovery of a novel chemical probe for elucidating the molecular mechanisms of the sexual dimorphism present within the melanocortin pathway. To further explore the melanocortin sexual dimorphism, hypothalamic gene expression was examined. The mRNA expression of the MC3R and proopiomelanocortin (POMC) were not significantly different between sexes. However, the expression of agouti-related peptide (AGRP) was significantly higher in female mice which may be a possible mechanism for the sex-specific effects observed with SKY2-23-7.

Characterization of ligand binding to melanocortin 4 receptors using fluorescent peptides with improved kinetic properties.

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Link, Reet; Veiksina, Santa; Rinken, Ago; Kopanchuk, Sergei

2017-03-15

Melanocortin 4 (MC 4 ) receptors are important drug targets as they regulate energy homeostasis, eating behaviour and sexual functions. The ligand binding process to these G protein-coupled receptors is subject to considerable complexity. Different steps in the complex dynamic regulation can be characterized by ligand binding kinetics. Optimization of these kinetic parameters in terms of on-rate and residence time can increase the rapid onset of drug action and reduce off-target effects. Fluorescence anisotropy (FA) is one of the homogeneous fluorescence-based assays that enable continuous online monitoring of ligand binding kinetics. FA has been implemented for the kinetic study of melanocortin MC 4 receptors expressed on budded baculoviruses. However, the slow dissociation of the fluorescently labelled peptide NDP-α-MSH does not enable reaching equilibrium nor enable more in-depth study of the binding mechanisms. To overcome this problem, two novel red-shifted fluorescent ligands were designed. These cyclized heptapeptide derivatives (UTBC101 and UTBC102) exhibited nanomolar affinity toward melanocortin MC 4 receptors but had relatively different kinetic properties. The dissociation half-lives of UTBC101 (τ 1/2 =160min) and UTBC102 (τ 1/2 =7min) were shorter compared to that what was previously reported for Cy3B-NDP-α-MSH (τ 1/2 =224min). The significantly shorter dissociation half-life of UTBC102 enables equilibrium in screening assays, whereas the higher affinity of UTBC101 helps to resolve a wider range of competitor potencies. These two ligands are suitable for further kinetic screening of novel melanocortin MC 4 receptor specific ligands and could complement each other in these studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual melanocortin-4 receptor and GLP-1 receptor agonism amplifies metabolic benefits in diet-induced obese mice

DEFF Research Database (Denmark)

Clemmensen, Christoffer; Finan, Brian; Fischer, Katrin

2015-01-01

We assessed the efficacy of simultaneous agonism at the glucagon-like peptide-1 receptor (GLP-1R) and the melanocortin-4 receptor (MC4R) for the treatment of obesity and diabetes in rodents. Diet-induced obese (DIO) mice were chronically treated with either the long-acting GLP-1R agonist liraglut...

Metal ion-mediated agonism and agonist enhancement in melanocortin MC1 and MC4 receptors

DEFF Research Database (Denmark)

Holst, Birgitte; Elling, Christian E; Schwartz, Thue W

2002-01-01

-melanocortin stimulating hormone (alpha-MSH) in the MC1 and MC4 receptors, respectively. In the presence of peptide agonist, Zn(II) acted as an enhancer on both receptors, because it shifted the dose-response curves to the left: most pronounced was a 6-fold increase in alpha-MSH potency on the MC1 receptor. The effect......An endogenous metal-ion site in the melanocortin MC1 and MC4 receptors was characterized mainly in transiently transfected COS-7 cells. ZnCl(2) alone stimulated signaling through the Gs pathway with a potency of 11 and 13 microm and an efficacy of 50 and 20% of that of alpha...... affinities and profiles were similar for a number of the 2,2'-bipyridine and 1,10-phenanthroline analogs in complex with Zn(II) in the MC1 and MC4 receptors. However, the potencies and efficacies of the metal-ion complexes were very different in the two receptors, and close to full agonism was obtained...

Central role for Melanocortin-4 receptors in offspring hypertension arising from maternal obesity

NARCIS (Netherlands)

Samuelsson, Anne Maj S; Mullier, Amandine; Maicas, Nuria; Oosterhuis, Nynke R.; Bae, Sung Eun; Novoselova, Tatiana V.; Chan, Li F.; Pombo, Joaquim M.; Taylor, Paul D.; Joles, Jaap A.; Coen, Clive W.; Balthasar, Nina; Poston, Lucilla

2016-01-01

Melanocortin-4 receptor (Mc4r)-expressing neurons in the autonomic nervous system, particularly in the paraventricular nucleus of the hypothalamus (PVH), play an essential role in blood pressure (BP) control. Mc4r-deficient (Mc4rKO) mice are severely obese but lack obesity-related hypertension; they

SNPs of melanocortin 4 receptor (MC4R) associated with body weight in Beagle dogs.

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Zeng, Ruixia; Zhang, Yibo; Du, Peng

2014-01-01

Melanocortin 4 receptor (MC4R), which is associated with inherited human obesity, is involoved in food intake and body weight of mammals. To study the relationships between MC4R gene polymorphism and body weight in Beagle dogs, we detected and compared the nucleotide sequence of the whole coding region and 3'- and 5'- flanking regions of the dog MC4R gene (1214 bp). In 120 Beagle dogs, two SNPs (A420C, C895T) were identified and their relation with body weight was analyzed with RFLP-PCR method. The results showed that the SNP at A420C was significantly associated with canine body weight trait when it changed amino acid 101 of the MC4R protein from asparagine to threonine, while canine body weight variations were significant in female dogs when MC4R nonsense mutation at C895T. It suggested that the two SNPs might affect the MC4R gene's function which was relative to body weight in Beagle dogs. Therefore, MC4R was a candidate gene for selecting different size dogs with the MC4R SNPs (A420C, C895T) being potentially valuable as a genetic marker.

Role of melanocortins in the central control of feeding.

Science.gov (United States)

Vergoni, A V; Bertolini, A

2000-09-29

of melanocortins in the complex machinery responsible for body weight homeostasis, is testified by the hyperphagia/obesity syndromes caused by mutations in the pro-opiomelanocortin (POMC) gene, or in the melanocortin MC(4) receptor gene, or in the agouti locus. Finally, recent evidences suggest that melanocortins could be involved in mediating the effects of leptin, and in controlling the expression of neuropeptide Y (NPY).

Molecular Therapy of Melanocortin-4-Receptor Obesity by an Autoregulatory BDNF Vector

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Jason J. Siu

2017-12-01

Full Text Available Mutations in the melanocortin-4-receptor (MC4R comprise the most common monogenic form of severe early-onset obesity, and conventional treatments are either ineffective long-term or contraindicated. Immediately downstream of MC4R—in the pathway for regulating energy balance—is brain-derived neurotrophic factor (BDNF. Our previous studies show that adeno-associated virus (AAV-mediated hypothalamic BDNF gene transfer alleviates obesity and diabetes in both diet-induced and genetic models. To facilitate clinical translation, we developed a built-in autoregulatory system to control therapeutic gene expression mimicking the body’s natural feedback systems. This autoregulatory approach leads to a sustainable plateau of body weight after substantial weight loss is achieved. Here, we examined the efficacy and safety of autoregulatory BDNF gene therapy in Mc4r heterozygous mice, which best resemble MC4R obese patients. Mc4r heterozygous mice were treated with either autoregulatory BDNF vector or YFP control and monitored for 30 weeks. BDNF gene therapy prevented the development of obesity and metabolic syndromes characterized by decreasing body weight and adiposity, suppressing food intake, alleviating hyperleptinemia and hyperinsulinemia, improving glucose and insulin tolerance, and increasing energy expenditure, without adverse cardiovascular function or behavioral disturbances. These safety and efficacy data provide preclinical evidence that BDNF gene therapy is a compelling treatment option for MC4R-deficient obese patients.

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.

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Joseph, Christine G; Wang, Xiang S; Scott, Joseph W; Bauzo, Rayna M; Xiang, Zhimin; Richards, Nigel G; Haskell-Luevano, Carrie

2004-12-30

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.

Brain-derived neurotrophic factor in human subjects with function-altering melanocortin-4 receptor variants

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In rodents, hypothalamic brain-derived neurotrophic factor (BDNF) expression appears to be regulated by melanocortin-4 receptor (MC4R) activity. The impact of MC4R genetic variation on circulating BDNF in humans is unknown. The objective of this study is to compare BDNF concentrations of subjects wi...

Chimeric NDP-MSH and MTII melanocortin peptides with agouti-related protein (AGRP) Arg-Phe-Phe amino acids possess agonist melanocortin receptor activity.

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Joseph, Christine G; Wilczynski, Andrzej; Holder, Jerry R; Xiang, Zhimin; Bauzo, Rayna M; Scott, Joseph W; Haskell-Luevano, Carrie

2003-12-01

Agouti-related protein (AGRP) is one of only two known endogenous antagonists of G-protein coupled receptors (GPCRs). Specifically, AGRP antagonizes the brain melanocortin-3 and -4 receptors involved in energy homeostasis, regulation of feeding behavior, and obesity. Alpha-melanocyte stimulating hormone (alpha-MSH) is one of the known endogenous agonists for these receptors. It has been hypothesized that the Arg-Phe-Phe (111-113) human AGRP amino acids may be mimicking the melanocortin agonist Phe-Arg-Trp (7-9) residue interactions with the melanocortin receptors that are important for both receptor molecular recognition and stimulation. To test this hypothesis, we generated thirteen chimeric peptide ligands based upon the melanocortin agonist peptides NDP-MSH (Ac-Ser-Tyr-Ser-Nle4-Glu-His-DPhe-Arg-Trp-Gly-Lys-Pro-Val-NH2) and MTII (Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2). In these chimeric ligands, the agonist DPhe-Arg-Trp amino acids were replaced by the AGRP Arg-Phe-Phe residues, and resulted in agonist activity at the mouse melanocortin receptors (mMC1R and mMC3-5Rs), supporting the hypothesis that the AGRP antagonist ligand Arg-Phe-Phe residues mimic the agonist Phe-Arg-Trp amino acids. Interestingly, the Ac-Ser-Tyr-Ser-Nle4-Glu-His-Arg-DPhe-Phe-Gly-Lys-Pro-Val-NH2 peptide possessed 7 nM mMC1R agonist potency, and is 850-fold selective for the mMC1R versus the mMC3R, 2300-fold selective for the mMC1R versus the mMC4R, and 60-fold selective for the MC1R versus the mMC5R, resulting in the discovery of a new peptide template for the design of melanocortin receptor selective ligands.

Identification of putative agouti-related protein(87-132)-melanocortin-4 receptor interactions by homology molecular modeling and validation using chimeric peptide ligands.

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Wilczynski, Andrzej; Wang, Xiang S; Joseph, Christine G; Xiang, Zhimin; Bauzo, Rayna M; Scott, Joseph W; Sorensen, Nicholas B; Shaw, Amanda M; Millard, William J; Richards, Nigel G; Haskell-Luevano, Carrie

2004-04-22

Agouti-related protein (AGRP) is one of only two naturally known antagonists of G-protein-coupled receptors (GPCRs) identified to date. Specifically, AGRP antagonizes the brain melanocortin-3 and -4 receptors involved in energy homeostasis. Alpha-melanocyte stimulating hormone (alpha-MSH) is one of the known endogenous agonists for these melanocortin receptors. Insight into putative interactions between the antagonist AGRP amino acids with the melanocortin-4 receptor (MC4R) may be important for the design of unique ligands for the treatment of obesity related diseases and is currently lacking in the literature. A three-dimensional homology molecular model of the mouse MC4 receptor complex with the hAGRP(87-132) ligand docked into the receptor has been developed to identify putative antagonist ligand-receptor interactions. Key putative AGRP-MC4R interactions include the Arg111 of hAGRP(87-132) interacting in a negatively charged pocket located in a cavity formed by transmembrane spanning (TM) helices 1, 2, 3, and 7, capped by the acidic first extracellular loop (EL1) and specifically with the conserved melanocortin receptor residues mMC4R Glu92 (TM2), mMC4R Asp114 (TM3), and mMC4R Asp118 (TM3). Additionally, Phe112 and Phe113 of hAGRP(87-132) putatively interact with an aromatic hydrophobic pocket formed by the mMC4 receptor residues Phe176 (TM4), Phe193 (TM5), Phe253 (TM6), and Phe254 (TM6). To validate the AGRP-mMC4R model complex presented herein from a ligand perspective, we generated nine chimeric peptide ligands based on a modified antagonist template of the hAGRP(109-118) (Tyr-c[Asp-Arg-Phe-Phe-Asn-Ala-Phe-Dpr]-Tyr-NH(2)). In these chimeric ligands, the antagonist AGRP Arg-Phe-Phe residues were replaced by the melanocortin agonist His/D-Phe-Arg-Trp amino acids. These peptides resulted in agonist activity at the mouse melanocortin receptors (mMC1R and mMC3-5Rs). The most notable results include the identification of a novel subnanomolar melanocortin peptide

Structure-activity relationships of the melanocortin tetrapeptide Ac-His-DPhe-Arg-Trp-NH(2) at the mouse melanocortin receptors: part 2 modifications at the Phe position.

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Holder, Jerry Ryan; Bauzo, Rayna M; Xiang, Zhimin; Haskell-Luevano, Carrie

2002-07-04

The melanocortin pathway is an important participant in skin pigmentation, steroidogenesis, obesity, energy homeostasis and exocrine gland function. The centrally located melanocortin-3 and melanocortin-4 receptors (MC3R, MC4R) are involved in the metabolic and food intake aspects of energy homeostasis and are stimulated by melanocortin agonists such as alpha-melanocyte stimulation hormone (alpha-MSH). The melanocortin agonists contain the putative message sequence "His-Phe-Arg-Trp," and it has been well-documented that inversion of chirality of the Phe to DPhe results in a dramatic increase in melanocortin receptor potency. Herein, we report a tetrapeptide library, based upon the template Ac-His-DPhe-Arg-Trp-NH(2), consisting of 26 members that have been modified at the DPhe(7) position (alpha-MSH numbering) and pharmacologically characterized for agonist and antagonist activity at the mouse melanocortin receptors MC1R, MC3R, MC4R, and MC5R. The most notable results of this study include the identification of the tetrapeptide Ac-His-(pI)DPhe-Arg-Trp-NH(2) that is a full nanomolar agonist at the mMC1 and mMC5 receptors, a mMC3R partial agonist with potent antagonist activity (pA(2) = 7.25, K(i) = 56 nM) and, but unexpectedly, is a potent agonist at the mMC4R (EC(50) = 25 nM). This ligand possesses novel melanocortin receptor pharmacology, as compared to previously reported peptides, and is potentially useful for in vivo studies to differentiate MC3R vs MC4R physiological roles in animal models, such as primates, where "knockout" animals are not viable options. The DNal(2') substitution for DPhe resulted in a mMC3R partial agonist with antagonist activity (pA(2) = 6.5, K(i) = 295 nM) and a mMC4R (pA(2) = 7.8, K(i) = 17 nM) antagonist possessing 60- and 425-fold decreased potency, respectively, as compared with SHU9119 at these receptors. Examination of this DNal(2')-containing tetrapeptide at the F254S and F259S mutant mMC4Rs resulted in agonist activity of this m

Functional expression of Squalus acanthias melanocortin-5 receptor in CHO cells: ligand selectivity and interaction with MRAP.

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Reinick, Christina L; Liang, Liang; Angleson, Josepha K; Dores, Robert M

2012-04-05

The melanocortin-5 receptor (MC(5)) of the dogfish Squalus acanthias (SacMC(5) receptor) can be functionally expressed in CHO cells in the absence of the co-expression of an exogenous MRAP cDNA. Both human ACTH(1-24) and dogfish ACTH(1-25) were much better stimulators of the SacMC(5) receptor than any of the mammalian or dogfish MSH ligands that were tested. The order of ligand selectivity for the dogfish melanocortins was ACTH(1-25)>αMSH>γ-MSH=δ-MSH>β-MSH. Unlike mammalian MC(5) receptors, the functional expression of the SacMC(5) receptor was not negatively impacted when the receptor was co-expressed with a cartilaginous fish (Callorhinchus milii) MRAP2 cDNA. However, co-expression with either mouse mMRAP1 or zebrafish zfMRAP1 increased the sensitivity of SacMC(5) receptor for hACTH(1-24) by at least one order of magnitude. Hence, SacMC(5) receptor has the potential to interact with MRAP1 orthologs and in this regard behaved more like a melanocortin MC(2) receptor ortholog than a melanocortin MC(5) receptor ortholog. These observations are discussed in light of the evolution of the melanocortin receptor gene family in cartilaginous fish, and the physiological implications of these observations are considered. Copyright © 2012 Elsevier B.V. All rights reserved.

Glutamate mediates the function of melanocortin receptor 4 on sim1 neurons in body weight regulation

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The melanocortin receptor 4 (MC4R) is a well-established mediator of body weight homeostasis. However, the neurotransmitter(s) that mediate MC4R function remain largely unknown; as a result, little is known about the second-order neurons of the MC4R neural pathway. Single-minded 1 (Sim1)-expressing ...

Val103Ile polymorphism of the melanocortin-4 receptor gene (MC4R) in cancer cachexia

International Nuclear Information System (INIS)

Knoll, Susanne; Zimmer, Sabiene; Hinney, Anke; Scherag, André; Neubauer, Andreas; Hebebrand, Johannes

2008-01-01

At present pathogenic mechanisms of cancer cachexia are poorly understood. Previous evidence in animal models implicates the melanocortin-4 receptor gene (MC4R) in the development of cancer cachexia. In humans, MC4R mutations that lead to an impaired receptor function are associated with obesity; in contrast, the most frequent polymorphism (Val103Ile, rs2229616; heterozygote frequency approximately 2%) was shown to be negatively associated with obesity. We tested if cancer patients that are homo-/heterozygous for the Val103Ile polymorphism are more likely to develop cachexia and/or a loss of appetite than non-carriers of the 103Ile-allele. BMI (body mass index in kg/m 2 ) of 509 patients (295 males) with malignant neoplasms was determined; additionally patients were asked about premorbid/pretherapeutical changes of appetite and weight loss. Cachexia was defined as a weight loss of at least 5% prior to initiation of therapy; to fulfil this criterion this weight loss had to occur independently of other plausible reasons; in single cases weight loss was the initial reason for seeing a physician. The average age in years (± SD) was 59.0 ± 14.5 (males: 58.8 ± 14.0, females 59.2 ± 14.0). Blood samples were taken for genotyping of the Val103Ile by PCR- RFLP. Most of the patients suffered from lymphoma, leukaemia and gastrointestinal tumours. 107 of the patients (21%) fulfilled our criteria for cancer cachexia. We did not detect association between the Val103Ile polymorphism and cancer cachexia. However, if we exploratively excluded the patients with early leucaemic stages, we detected a trend towards the opposite effect (p < 0.05); heterozygotes for the 103Ile-allele developed cancer cachexia less frequently in comparison to the rest of the study group. Changes of appetite were not associated with the 103Ile-allele carrier status (p > 0.39). Heterozygotes for the 103Ile-allele are not more prone to develop cancer cachexia than patients without this allele; possibly

Val103Ile polymorphism of the melanocortin-4 receptor gene (MC4R) in cancer cachexia

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Knoll, Susanne; Zimmer, Sabiene [Department of Child and Adolescent Psychiatry, University of Duisburg-Essen (Germany); Department of Hematology/Oncology/Immunology, University of Marburg (Germany); Hinney, Anke [Department of Child and Adolescent Psychiatry, University of Duisburg-Essen (Germany); Scherag, André [Zentrum for clinical studies food (ZKSE) c/o Institute for Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen (Germany); Neubauer, Andreas [Department of Hematology/Oncology/Immunology, University of Marburg (Germany); Hebebrand, Johannes [Department of Child and Adolescent Psychiatry, University of Duisburg-Essen (Germany)

2008-03-31

At present pathogenic mechanisms of cancer cachexia are poorly understood. Previous evidence in animal models implicates the melanocortin-4 receptor gene (MC4R) in the development of cancer cachexia. In humans, MC4R mutations that lead to an impaired receptor function are associated with obesity; in contrast, the most frequent polymorphism (Val103Ile, rs2229616; heterozygote frequency approximately 2%) was shown to be negatively associated with obesity. We tested if cancer patients that are homo-/heterozygous for the Val103Ile polymorphism are more likely to develop cachexia and/or a loss of appetite than non-carriers of the 103Ile-allele. BMI (body mass index in kg/m{sup 2}) of 509 patients (295 males) with malignant neoplasms was determined; additionally patients were asked about premorbid/pretherapeutical changes of appetite and weight loss. Cachexia was defined as a weight loss of at least 5% prior to initiation of therapy; to fulfil this criterion this weight loss had to occur independently of other plausible reasons; in single cases weight loss was the initial reason for seeing a physician. The average age in years (± SD) was 59.0 ± 14.5 (males: 58.8 ± 14.0, females 59.2 ± 14.0). Blood samples were taken for genotyping of the Val103Ile by PCR- RFLP. Most of the patients suffered from lymphoma, leukaemia and gastrointestinal tumours. 107 of the patients (21%) fulfilled our criteria for cancer cachexia. We did not detect association between the Val103Ile polymorphism and cancer cachexia. However, if we exploratively excluded the patients with early leucaemic stages, we detected a trend towards the opposite effect (p < 0.05); heterozygotes for the 103Ile-allele developed cancer cachexia less frequently in comparison to the rest of the study group. Changes of appetite were not associated with the 103Ile-allele carrier status (p > 0.39). Heterozygotes for the 103Ile-allele are not more prone to develop cancer cachexia than patients without this allele

Successful Treatment with Atomoxetine of an Adolescent Boy with Attention Deficit/Hyperactivity Disorder, Extreme Obesity, and Reduced Melanocortin 4 Receptor Function

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Wilfried Pott

2013-03-01

Full Text Available Objective: Recent case reports suggest a link between reduced melanocortinergic tone and both obesity and attention deficit / hyperactivity disorder (ADHD. We present the case of a 13-year-old, male, obese MC4R mutation carrier with ADHD. Case Report: The boy carries a heterozygous mutation in the melanocortin 4 receptor gene (MC4R; Met281Val, that leads to a reduced receptor function. Dominant mutations of this type represent major gene effects for obesity. He participated in a lifestyle intervention program for obesity and received treatment with the selective norepinephrine re-uptake inhibitor atomoxetine for 31 months. The boy markedly reduced his BMI from 47.2 to 29.6 kg/m². Conclusion: Atomoxetine proved to efficiently reduce weight in a severely obese MC4R mutation carrier with ADHD. We briefly discuss possible mechanisms for our observation, including evidence for the functional connectivity between melanocortinergic, dopaminergic, and norepinephrinergic brain circuitries.

Structure-activity relationships of the melanocortin tetrapeptide Ac-His-DPhe-Arg-Trp-NH(2) at the mouse melanocortin receptors. 1. Modifications at the His position.

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Holder, Jerry Ryan; Bauzo, Rayna M; Xiang, Zhimin; Haskell-Luevano, Carrie

2002-06-20

The melanocortin pathway is an important participant in obesity and energy homeostasis. The centrally located melanocortin-3 and melanocortin-4 receptors (MC3R, MC4R) are involved in the metabolic and food intake aspects of energy homeostasis and are stimulated by melanocortin agonists such as alpha-melanocyte stimulation hormone (alpha-MSH). The melanocortin agonists contain the putative message sequence "His-Phe-Arg-Trp", and it has been well documented that inversion of chirality of the Phe to DPhe results in a dramatic increase in melanocortin receptor potency. Herein, we report a tetrapeptide library based on the template Ac-His-DPhe-Arg-Trp-NH(2), consisting of 17 members that have been modified at the His(6) position (alpha-MSH numbering) and pharmacologically characterized for agonist activity at the mouse melanocortin receptors MC1R, MC3R, MC4R, and MC5R. These studies provide further experimental evidence that the His(6) position can determine MC4R versus MC3R agonist selectivity and that chemically nonreactive side chains may be substituted for the imidazole ring (generally needs to be side chain protected in synthetic schemes) in the design of MC4R-selective, small-molecule, non-peptide agonists. Specifically, the tetrapeptide containing the amino-2-naphthylcarboxylic acid (Anc) amino acid at the His position resulted in a potent agonist at the mMC4R (EC(50) = 21 nM), was a weak mMC3R micromolar antagonist (pA(2) = 5.6, K(i) = 2.5 microM), and possessed >4700-fold agonist selectivity for the MC4R versus the MC3R. Substitution of the His(6) amino acid in the tetrapeptide template by the Phe, Anc, 3-(2-thienyl)alanine (2Thi), and 3-(4-pyridinyl)alanine (4-Pal) resulted in equipotency or only up to a 7-fold decrease in potency, compared to the His(6)-containing tetrapeptide at the mMC4R, demonstrating that these amino acid side chains may be substituted for the imidazole in the design of MC4R-selective non-peptide molecules.

Profound and Rapid Reduction in Body Temperature Induced by the Melanocortin Receptor Agonists

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Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-01-01

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5′AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII’s effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. PMID:25065745

Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists.

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Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

2014-08-22

The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5'AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII's effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

Peptide and small molecules rescue the functional activity and agonist potency of dysfunctional human melanocortin-4 receptor polymorphisms.

Science.gov (United States)

Xiang, Zhimin; Pogozheva, Irina D; Sorenson, Nicholas B; Wilczynski, Andrzej M; Holder, Jerry Ryan; Litherland, Sally A; Millard, William J; Mosberg, Henry I; Haskell-Luevano, Carrie

2007-07-17

The melanocortin pathway, specifically the melanocortin-4 receptor and the cognate endogenous agonist and antagonist ligands, have been strongly implicated in the regulation of energy homeostasis and satiety. Genetic studies of morbidly obese human patients and normal weight control patients have resulted in the discovery of over 70 human melanocortin-4 receptor (MC4R) polymorphisms observed as both heterozygous and homozygous forms. A number of laboratories have been studying these hMC4R polymorphisms attempting to understand the molecular mechanism(s) that might explain the obese human phenotype. Herein, we have studied 13 polymorphic hMC4Rs that have been identified to possess statistically significant decreased endogenous agonist potency with synthetic peptides and small molecules attempting to identify ligands that can pharmacologically rescue the hMC4R polymorphic agonist response. The ligands examined in this study include NDP-MSH, MTII, Ac-His-DPhe-Arg-Trp-NH2 (JRH887-9), Ac-Anc-DPhe-Arg-Trp-NH2 (amino-2-naphtylcarboxylic acid, Anc, JRH420-12), Ac-His-(pI)DPhe-Arg-Trp-NH2 (JRH322-18), chimeric AGRP-melanocortin based ligands (Tyr-c[Cys-His-DPhe-Arg-Trp-Asn-Ala-Phe-Cys]-Tyr-NH2, AMW3-130 and Ac-mini-(His-DPhe-Arg-Trp)-hAGRP-NH2, AMW3-106), and the small molecules JB25 and THIQ. The hMC4R polymorphisms included in this study are S58C, N97D, I102S, L106P, S127L, T150I, R165Q, R165W, L250Q, G252S, C271Y, Y287Stop, and I301T. These studies resulted in the NDP-MSH, MTII, AMW3-130, THIQ, and AMW3-106 ligands possessing nanomolar to subnanomolar agonist potency at the hMC4R polymorphisms examined in this study. Thus, these ligands could generically rescue the potency and stimulatory response of the abnormally functioning hMC4Rs studied and may provide tools to further clarify the molecular mechanism(s) involving these receptor modifications.

Conformational study on cyclic melanocortin ligands and new insight into their binding mode at the MC4 receptor.

Science.gov (United States)

Grieco, Paolo; Brancaccio, Diego; Novellino, Ettore; Hruby, Victor J; Carotenuto, Alfonso

2011-09-01

The melanocortin receptors are involved in many physiological functions, including pigmentation, sexual function, feeding behavior, and energy homeostasis, making them potential targets to treat obesity, sexual dysfunction, etc. Understanding the basis of the ligand-receptor interactions is crucial for the design of potent and selective ligands for these receptors. The conformational preferences of the cyclic melanocortin ligands MTII (Ac-Nle(4)-c[Asp(5)-His(6)-DPhe(7)-Arg(8)-Trp(9)-Lys(10)]-NH(2)) and SHU9119 (Ac-Nle(4)-c[Asp(5)-His(6)-DNal(2')(7)-Arg(8)-Trp(9)-Lys(10)]-NH(2)), which show agonist and antagonist activity at the h-MC4R, respectively, were comprehensively investigated by solution NMR spectroscopy in different environments. In particular, water and water/DMSO (8:2) solutions were used as isotropic solutions and an aqueous solution of DPC (dodecylphosphocholine) micelles was used as a membrane mimetic environment. NMR-derived conformations of these two ligands were docked within h-MC4R models. NMR and docking studies revealed intriguing differences which can help explain the different activities of these two ligands. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Melanocortin 4 Receptor Activation Attenuates Mitochondrial Dysfunction in Skeletal Muscle of Diabetic Rats.

Science.gov (United States)

Zhang, Hao-Hao; Liu, Jiao; Qin, Gui-Jun; Li, Xia-Lian; Du, Pei-Jie; Hao, Xiao; Zhao, Di; Tian, Tian; Wu, Jing; Yun, Meng; Bai, Yan-Hui

2017-11-01

A previous study has confirmed that the central melanocortin system was able to mediate skeletal muscle AMP-activated protein kinase (AMPK) activation in mice fed a high-fat diet, while activation of the AMPK signaling pathway significantly induced mitochondrial biogenesis. Our hypothesis was that melanocortin 4 receptor (MC4R) was involved in the development of skeletal muscle injury in diabetic rats. In this study, we treated diabetic rats intracerebroventricularly with MC4R agonist R027-3225 or antagonist SHU9119, respectively. Then, we measured the production of reactive oxygen species (ROS), the levels of malondialdehyde (MDA) and glutathione (GSH), the mitochondrial DNA (mtDNA) content and mitochondrial biogenesis, and the protein levels of p-AMPK, AMPK, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), sirtuin 1 (SIRT1), and manganese superoxide dismutase (MnSOD) in the skeletal muscle of diabetic rats. The results showed that there was significant skeletal muscle injury in the diabetic rats along with serious oxidative stress and decreased mitochondrial biogenesis. Treatment with R027-3225 reduced oxidative stress and induced mitochondrial biogenesis in skeletal muscle, and also activated the AMPK-SIRT1-PGC-1α signaling pathway. However, diabetic rats injected with MC4R antagonist SHU9119 showed an aggravated oxidative stress and mitochondrial dysfunction in skeletal muscle. In conclusion, our results revealed that MC4R activation was able to attenuate oxidative stress and mitochondrial dysfunction in skeletal muscle induced by diabetes partially through activating the AMPK-SIRT1-PGC-1α signaling pathway. J. Cell. Biochem. 118: 4072-4079, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Functional characterization of the modified melanocortin peptides responsible for ligand selectivity at the human melanocortin receptors.

Science.gov (United States)

Chen, Min; Georgeson, Keith E; Harmon, Carroll M; Haskell-Luevano, Carrie; Yang, Yingkui

2006-11-01

The melanocortin system plays an important role in energy homeostasis as well as skin pigmentation, steroidogenesis and exocrine gland function. In this study, we examined eight Ac-His-Phe-Arg-Trp-NH(2) tetrapeptides that were modified at the Phe position and pharmacologically characterized their activities at the human MCR wild-types and their mutants. Our results indicate that at the hMC1R, all D stereochemical modified residues at the Phe position of peptides increase cAMP production in a dose-dependent manner. At the hMC3R, the DPhe peptide dose dependently increases cAMP production but all other three tetrapeptides were not. At the hMC4R, both the DPhe and DNal(1') peptides induce cAMP production. However, both DTyr and DNal(2') were not able to induce cAMP production. Further studies indicated that at the hMC1R M128L mutant receptor, the all D-configured tetrapeptides reduce their potencies as compared to that of hMC1R wild-type. However, at the hMC3R and hMC4R L165M and L133M mutant receptors, the DNal(2') and DTyr tetrapeptides possess agonist activity. These findings indicate that DPhe in tetrapeptide plays an important role in ligand selectivity and specific residue TM3 of the melanocortin receptors is crucial for ligand selectivity.

Structural Insights into Selective Ligand-Receptor Interactions Leading to Receptor Inactivation Utilizing Selective Melanocortin 3 Receptor Antagonists.

Science.gov (United States)

Cai, Minying; Marelli, Udaya Kiran; Mertz, Blake; Beck, Johannes G; Opperer, Florian; Rechenmacher, Florian; Kessler, Horst; Hruby, Victor J

2017-08-15

Systematic N-methylated derivatives of the melanocortin receptor ligand, SHU9119, lead to multiple binding and functional selectivity toward melanocortin receptors. However, the relationship between N-methylation-induced conformational changes in the peptide backbone and side chains and melanocortin receptor selectivity is still unknown. We conducted comprehensive conformational studies in solution of two selective antagonists of the third isoform of the melanocortin receptor (hMC3R), namely, Ac-Nle-c[Asp-NMe-His 6 -d-Nal(2') 7 -NMe-Arg 8 -Trp 9 -Lys]-NH 2 (15) and Ac-Nle-c[Asp-His 6 -d-Nal(2') 7 -NMe-Arg 8 -NMe-Trp 9 -NMe-Lys]-NH 2 (17). It is known that the pharmacophore (His 6 -DNal 7 -Arg 8 -Trp 9 ) of the SHU-9119 peptides occupies a β II-turn-like region with the turn centered about DNal 7 -Arg 8 . The analogues with hMC3R selectivity showed distinct differences in the spatial arrangement of the Trp 9 side chains. In addition to our NMR studies, we also carried out molecular-level interaction studies of these two peptides at the homology model of hMC3R. Earlier chimeric human melanocortin 3 receptor studies revealed insights regarding the binding and functional sites of hMC3R selectivity. Upon docking of peptides 15 and 17 to the binding pocket of hMC3R, it was revealed that Arg 8 and Trp 9 side chains are involved in a majority of the interactions with the receptor. While Arg 8 forms polar contacts with D154 and D158 of hMC3R, Trp 9 utilizes π-π stacking interactions with F295 and F298, located on the transmembrane domain of hMC3R. It is hypothesized that as the frequency of Trp 9 -hMC3R interactions decrease, antagonistic activity increases. The absence of any interactions of the N-methyl groups with hMC3R suggests that their primary function is to modulate backbone conformations of the ligands.

Loss of melanocortin-4 receptor function attenuates HPA responses to psychological stress

DEFF Research Database (Denmark)

Ryan, Karen K; Mul, Joram D; Clemmensen, Christoffer

2014-01-01

function. These results support the hypothesis that endogenous MC4R signaling contributes to the HPA axis response to stress. Because MC4R plays a critical role in the regulation of energy balance, the present work suggests that it may also serve as an important communication link between brain metabolic...... in hypothalamic-pituitary-adrenocortical axis (HPA) regulation. The present work investigated the role of chronic Mc4r function to modulate basal HPA axis tone and to facilitate acute HPA responses to psychological stress, using a novel rat model with Mc4r loss-of-function. In this study, adult male rats were......The melanocortin 4 receptor (MC4R), well-known for its role in the regulation of energy balance, is widely expressed in stress-regulatory brain regions, including the paraventricular nucleus of the hypothalamus (PVH) and the medial amygdala (MeA). In agreement with this, MC4R has been implicated...

MRAP and MRAP2 are bidirectional regulators of the melanocortin receptor family

OpenAIRE

Chan, Li F.; Webb, Tom R.; Chung, Teng-Teng; Meimaridou, Eirini; Cooray, Sadani N.; Guasti, Leonardo; Chapple, J. Paul; Egertová, Michaela; Elphick, Maurice R.; Cheetham, Michael E.; Metherell, Louise A.; Clark, Adrian J. L.

2009-01-01

The melanocortin receptor (MCR) family consists of 5 G protein-coupled receptors (MC1R–MC5R) with diverse physiologic roles. MC2R is a critical component of the hypothalamic–pituitary–adrenal axis, whereas MC3R and MC4R have an essential role in energy homeostasis. Mutations in MC4R are the single most common cause of monogenic obesity. Investigating the way in which these receptors signal and traffic to the cell membrane is vital in understanding disease processes related to MCR dysfunction....

Association of the melanocortin 4 receptor gene rs17782313 polymorphism with rewarding value of food and eating behavior in Chilean children.

Science.gov (United States)

Obregón, A M; Oyarce, K; Santos, J L; Valladares, M; Goldfield, G

2017-02-01

Studies conducted in monozygotic and dizygotic twins have established a strong genetic component in eating behavior. Rare mutations and common variants of the melanocortin 4 receptor (MC4R) gene have been linked to obesity and eating behavior scores. However, few studies have assessed common variants in MC4R gene with the rewarding value of food in children. The objective of the study was to evaluate the association between the MC4R rs17782313 polymorphism with homeostatic and non-homeostatic eating behavior patterns in Chileans children. This is a cross-sectional study in 258 Chilean children (44 % female, 8-14 years old) showing a wide variation in BMI. Anthropometric measurements (weight, height, Z-score of BMI and waist circumference) were performed by standard procedures. Eating behavior was assessed using the Eating in Absence of Hunger Questionnaire (EAHQ), the Child Eating Behavior Questionnaire (CEBQ), the Three-Factor Eating Questionnaire (TFEQ), and the Food Reinforcement Value Questionnaire (FRVQ). Genotype of the rs17782313 nearby MC4R was determined by a Taqman assay. Association of the rs17782313 C allele with eating behavior was assessed using non-parametric tests. We found that children carrying the CC genotype have higher scores of food responsiveness (p value = 0.02). In obese girls, carriers of the C allele showed lower scores of satiety responsiveness (p value = 0.02) and higher scores of uncontrolled eating (p value = 0.01). Obese boys carrying the C allele showed lower rewarding value of food in relation to non-carriers. The rs17782313 C allele is associated with eating behavior traits that may predispose obese children to increased energy intake and obesity.

A Macrocyclic Agouti-Related Protein/[Nle4, DPhe7]α-Melanocyte Stimulating Hormone Chimeric Scaffold Produces Sub-nanomolar Melanocortin Receptor Ligands

OpenAIRE

Ericson, Mark D.; Freeman, Katie T.; Schnell, Sathya M.; Haskell-Luevano, Carrie

2017-01-01

The melanocortin system consists of five receptor subtypes, endogenous agonists, and naturally occurring antagonists. These receptors and ligands have been implicated in numerous biological pathways including processes linked to obesity and food intake. Herein, a truncation structure-activity relationship study of chimeric agouti-related protein (AGRP)/[Nle4, DPhe7]α-Melanocyte Stimulating Hormone (NDP-MSH) ligands is reported. The tetrapeptide His-DPhe-Arg-Trp or tripeptide DPhe-Arg-Trp repl...

Patients with Obesity Caused by Melanocortin-4 Receptor Mutations Can Be Treated with a Glucagon-like Peptide-1 Receptor Agonist

DEFF Research Database (Denmark)

Iepsen, Eva W; Zhang, Jinyi; Thomsen, Henrik S

2018-01-01

Pathogenic mutations in the appetite-regulating melanocortin-4 receptor (MC4R) represent the most common cause of monogenic obesity with limited treatment options. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) cause weight loss by reducing appetite. We assessed the effect of the GLP-1 RA...... liraglutide 3.0 mg for 16 weeks in 14 obese individuals with pathogenic MC4R mutations (BMI 37.5 ± 6.8) and 28 matched control participants without MC4R mutation (BMI 36.8 ± 4.8). Liraglutide decreased body weight by 6.8 kg ± 1.8 kg in individuals with pathogenic MC4R mutations and by 6.1 kg ± 1.2 kg...... in control participants. Total body fat, waist circumference, and fasting and postprandial glucose concentrations similarly decreased in both groups. Thus, liraglutide induced an equal, clinically significant weight loss of 6% in both groups, indicating that the appetite-reducing effect of liraglutide...

Hypothesis and Theory: Revisiting Views on the Co-evolution of the Melanocortin Receptors and the Accessory Proteins, MRAP1 and MRAP2.

Science.gov (United States)

Dores, Robert M

2016-01-01

The evolution of the melanocortin receptors (MCRs) is closely associated with the evolution of the melanocortin-2 receptor accessory proteins (MRAPs). Recent annotation of the elephant shark genome project revealed the sequence of a putative MRAP1 ortholog. The presence of this sequence in the genome of a cartilaginous fish raises the possibility that the mrap1 and mrap2 genes in the genomes of gnathostome vertebrates were the result of the chordate 2R genome duplication event. The presence of a putative MRAP1 ortholog in a cartilaginous fish genome is perplexing. Recent studies on melanocortin-2 receptor (MC2R) in the genomes of the elephant shark and the Japanese stingray indicate that these MC2R orthologs can be functionally expressed in CHO cells without co-expression of an exogenous mrap1 cDNA. The novel ligand selectivity of these cartilaginous fish MC2R orthologs is discussed. Finally, the origin of the mc2r and mc5r genes is reevaluated. The distinctive primary sequence conservation of MC2R and MC5R is discussed in light of the physiological roles of these two MCR paralogs.

Linear scaffolds for multivalent targeting of melanocortin receptors.

Science.gov (United States)

Dehigaspitiya, Dilani Chathurika; Anglin, Bobbi L; Smith, Kara R; Weber, Craig S; Lynch, Ronald M; Mash, Eugene A

2015-12-21

Molecules bearing one, two, three, or four copies of the tetrapeptide His-dPhe-Arg-Trp were attached to scaffolds based on ethylene glycol, glycerol, and d-mannitol by means of the copper-assisted azide-alkyne cyclization. The abilities of these compounds to block binding of a probe at the melanocortin 4 receptor were evaluated using a competitive binding assay. All of the multivalent molecules studied exhibited 30- to 40-fold higher apparent affinites when compared to a monovalent control. These results are consistent with divalent binding to receptor dimers. No evidence for tri- or tetravalent binding was obtained. Differences in the interligand spacing required for divalent binding, as opposed to tri- or tetravalent binding, may be responsible for these results.

Melanocortin receptor accessory proteins in adrenal gland physiology and beyond.

Science.gov (United States)

Novoselova, T V; Jackson, D; Campbell, D C; Clark, A J L; Chan, L F

2013-04-01

The melanocortin receptor (MCR) family consists of five G-protein-coupled receptors (MC1R-MC5R) with diverse physiological roles. MC1R controls pigmentation, MC2R is a critical component of the hypothalamic-pituitary-adrenal axis, MC3R and MC4R have a vital role in energy homeostasis and MC5R is involved in exocrine function. The melanocortin receptor accessory protein (MRAP) and its paralogue MRAP2 are small single-pass transmembrane proteins that have been shown to regulate MCR expression and function. In the adrenal gland, MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency, where inactivating MRAP mutations account for ∼20% of cases. MRAP is highly expressed in both the zona fasciculata and the undifferentiated zone. Expression in the undifferentiated zone suggests that MRAP could also be important in adrenal cell differentiation and/or maintenance. In contrast, the role of adrenal MRAP2, which is highly expressed in the foetal gland, is unclear. The expression of MRAPs outside the adrenal gland is suggestive of a wider physiological purpose, beyond MC2R-mediated adrenal steroidogenesis. In vitro, MRAPs have been shown to reduce surface expression and signalling of all the other MCRs (MC1,3,4,5R). MRAP2 is predominantly expressed in the hypothalamus, a site that also expresses a high level of MC3R and MC4R. This raises the intriguing possibility of a CNS role for the MRAPs.

Effects of melanocortin-4 receptor agonists and antagonists on expression of genes related to reproduction in spotted scat, Scatophagus argus.

Science.gov (United States)

Jiang, Dong-Neng; Li, Jian-Tao; Tao, Ya-Xiong; Chen, Hua-Pu; Deng, Si-Ping; Zhu, Chun-Hua; Li, Guang-Li

2017-05-01

Melanocortin-4 receptor (Mc4r) function related to reproduction in fish has not been extensively investigated. Here, we report on gene expression changes by real-time PCR following treatment with Mc4r agonists and antagonists in the spotted scat (Scatophagus argus). Using in vitro incubated hypothalamus, the Mc4r nonselective agonist NDP-MSH ([Nle 4 , D-Phe 7 ]-α-melanocyte stimulating hormone; 10 -6 M) and selective agonist THIQ (N-[(3R)-1, 2, 3, 4-Tetrahydroisoquinolinium-3-ylcarbonyl]- (1R)-1-(4-chlorobenzyl)-2-[4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl) piperidin-1-yl]-2-oxoethylamine; 10 -7 M) significantly increased the expression of gnrh (Gonadotropin releasing hormone), while the Mc4r nonselective antagonist SHU9119 (Ac-Nle-[Asp-His-DPhe/DNal(2')-Arg-Trp-Lys]-NH2; 10 -6 M) and selective antagonist Ipsen 5i (compound 5i synthesized in Ipsen Research Laboratories; 10 -6 M) significantly inhibited gnrh expression after 3 h of incubation. In incubated pituitary tissue, NDP-MSH and THIQ significantly increased the expression of fshb (Follicle-stimulating hormone beta subunit) and lhb (Luteinizing hormone beta subunit), while SHU9119 and Ipsen 5i significantly decreased fshb and lhb expression after 3 h of incubation. During the in vivo experiment, THIQ (1 mg/kg bw) significantly increased gnrh expression in hypothalamic tissue, as well as the fshb and lhb expression in pituitary tissue 12 h after abdominal injection. Furthermore, Ipsen 5i (1 mg/kg bw) significantly inhibited gnrh expression in hypothalamic tissue, as well as fshb and lhb gene expression in pituitary tissue 12 h after abdominal injection. In summary, Mc4r singling appears to stimulate gnrh expression in the hypothalamus, thereby modulating the synthesis of Fsh and Lh in the pituitary. In addition, Mc4r also appears to directly regulate fshb and lhb levels in the pituitary in spotted scat. Our study suggests that Mc4r, through the hypothalamus and pituitary, participates in reproductive

A Macrocyclic Agouti-Related Protein/[Nle4,DPhe7]α-Melanocyte Stimulating Hormone Chimeric Scaffold Produces Subnanomolar Melanocortin Receptor Ligands.

Science.gov (United States)

Ericson, Mark D; Freeman, Katie T; Schnell, Sathya M; Haskell-Luevano, Carrie

2017-01-26

The melanocortin system consists of five receptor subtypes, endogenous agonists, and naturally occurring antagonists. These receptors and ligands have been implicated in numerous biological pathways including processes linked to obesity and food intake. Herein, a truncation structure-activity relationship study of chimeric agouti-related protein (AGRP)/[Nle4,DPhe7]α-melanocyte stimulating hormone (NDP-MSH) ligands is reported. The tetrapeptide His-DPhe-Arg-Trp or tripeptide DPhe-Arg-Trp replaced the Arg-Phe-Phe sequence in the AGRP active loop derivative c[Pro-Arg-Phe-Phe-Xxx-Ala-Phe-DPro], where Xxx was the native Asn of AGRP or a diaminopropionic (Dap) acid residue previously shown to increase antagonist potency at the mMC4R. The Phe, Ala, and Dap/Asn residues were successively removed to generate a 14-member library that was assayed for agonist activity at the mouse MC1R, MC3R, MC4R, and MC5R. Two compounds possessed nanomolar agonist potency at the mMC4R, c[Pro-His-DPhe-Arg-Trp-Asn-Ala-Phe-DPro] and c[Pro-His-DPhe-Arg-Trp-Dap-Ala-DPro], and may be further developed to generate novel melanocortin probes and ligands for understanding and treating obesity.

Inhibition of the central melanocortin system decreases brown adipose tissue activity

NARCIS (Netherlands)

Kooijman, S.; Boon, M.R.; Parlevliet, E.T.; Geerling, J.J.; Pol, V. van de; Romijn, J.A.; Havekes, L.M.; Meurs, I.; Rensen, P.C.N.

2014-01-01

The melanocortin system is an important regulator of energy balance, and melanocortin 4 receptor (MC4R) deficiency is the most common monogenic cause of obesity. We investigated whether the relationship between melanocortin system activity and energy expenditure (EE) is mediated by brown adipose

Design, synthesis and characterisation of gurmarin and melanocortin analogues of gurmarin

DEFF Research Database (Denmark)

Eliasen, Rasmus

as molecular scaffolds into which peptide sequences of pharmaceutical interest can be incorporated, thus providing highly stable drug candidates. The melanocortin receptors are a family of five G protein-coupled receptors distributed throughout the body. The melanocortin 4 receptor is found in the brain where...... it regulates appetite and energy expenditure. The melanocortin receptors are activated by peptides containing a His-Phe-Arg-Trp tetrapeptide sequence. Consequently, inhibitor cystine knotted peptides in which this tetrapeptide are grafted could provide novel appetite regulating peptides for the treatment...

Comparative Functional Alanine Positional Scanning of the α-Melanocyte Stimulating Hormone and NDP-Melanocyte Stimulating Hormone Demonstrates Differential Structure-Activity Relationships at the Mouse Melanocortin Receptors.

Science.gov (United States)

Todorovic, Aleksandar; Ericson, Mark D; Palusak, Ryan D; Sorensen, Nicholas B; Wood, Michael S; Xiang, Zhimin; Haskell-Luevano, Carrie

2016-07-20

The melanocortin system has been implicated in the regulation of various physiological functions including melanogenesis, steroidogenesis, energy homeostasis, and feeding behavior. Five melanocortin receptors have been identified to date and belong to the family of G protein-coupled receptors (GPCR). Post-translational modification of the proopiomelanocortin (POMC) prohormone leads to the biosynthesis of the endogenous melanocortin agonists, including α-melanocyte stimulating hormone (α-MSH), β-MSH, γ-MSH, and adrenocorticotropic hormone (ACTH). All the melanocortin agonists derived from the POMC prohormone contain a His-Phe-Arg-Trp tetrapeptide sequence that has been implicated in eliciting the pharmacological responses at the melanocortin receptors. Herein, an alanine (Ala) positional scan is reported for the endogenous α-MSH ligand and the synthetic, more potent, NDP-MSH peptide (Ac-Ser(1)-Tyr(2)-Ser(3)-Nle(4)-Glu(5)-His(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH2) at the cloned mouse melanocortin receptors to test the assumption that the structure-activity relationships of one ligand would apply to the other. Several residues outside of the postulated pharmacophore altered potency at the melanocortin receptors, most notably the 1560-, 37-, and 15-fold potency loss when the Glu(5) position of α-MSH was substituted with Ala at the mMC1R, mMC3R, and mMC4R, respectively. Importantly, the altered potencies due to Ala substitutions in α-MSH did not necessarily correlate with equivalent Ala substitutions in NDP-MSH, indicating that structural modifications and corresponding biological activities in one of these melanocortin ligands may not be predictive for the other agonist.

Evidence for natural selection at the melanocortin-3 receptor gene in European and African populations.

Science.gov (United States)

Yoshiuchi, Issei

2016-08-01

Obesity is increasing steadily in worldwide prevalence and is known to cause serious health problems in association with type 2 diabetes mellitus (T2DM), including hypertension, stroke, and cardiovascular diseases. According to the thrifty gene hypothesis, the natural selection of obesity-related genes is important during feast and famine because they control body weight and fat levels. Past human adaptations to environmental changes in food supply, lifestyle, and geography may have influenced the selection of genes associated with the metabolism of glucose, lipids, and energy. The melanocortin-3 receptor gene (MC3R) is associated with obesity, with MC3R-deficient mice showing increased fat mass. MC3R variations are also linked with childhood obesity and insulin resistance. Here, we aimed to uncover evidence of selection at MC3R. We performed a three-step method to detect selection at MC3R using HapMap population data. We used Wright's F statistics as a measure of population differentiation, the long-range haplotype test to identify extended haplotypes, and the integrated haplotype score (iHS) to detect selection at MC3R. We observed high population differentiation between European and African populations at two MC3R childhood obesity- and insulin resistance-associated single-nucleotide polymorphisms (rs3746619 and rs3827103) using Wright's F statistics. The iHS revealed evidence of natural selection at MC3R. These findings provide evidence for natural selection at MC3R. Further investigation is warranted into adaptive evolution at T2DM- and obesity-associated genes.

An essential role for the K+-dependent Na+/Ca2+-exchanger, NCKX4, in melanocortin-4-receptor-dependent satiety.

Science.gov (United States)

Li, Xiao-Fang; Lytton, Jonathan

2014-09-12

K(+)-dependent Na(+)/Ca(2+)-exchangers are broadly expressed in various tissues, and particularly enriched in neurons of the brain. The distinct physiological roles for the different members of this Ca(2+) transporter family are, however, not well described. Here we show that gene-targeted mice lacking the K(+)-dependent Na(+)/Ca(2+)-exchanger, NCKX4 (gene slc24a4 or Nckx4), display a remarkable anorexia with severe hypophagia and weight loss. Feeding and satiety are coordinated centrally by melanocortin-4 receptors (MC4R) in neurons of the hypothalamic paraventricular nucleus (PVN). The hypophagic response of Nckx4 knock-out mice is accompanied by hyperactivation of neurons in the PVN, evidenced by high levels of c-Fos expression. The activation of PVN neurons in both fasted Nckx4 knock-out and glucose-injected wild-type animals is blocked by Ca(2+) removal and MC4R antagonists. In cultured hypothalamic neurons, melanocyte stimulating hormone induces an MC4R-dependent and sustained Ca(2+) signal, which requires phospholipase C activity and plasma membrane Ca(2+) entry. The Ca(2+) signal is enhanced in hypothalamic neurons from Nckx4 knock-out animals, and is depressed in cells in which NCKX4 is overexpressed. Finally, MC4R-dependent oxytocin expression in the PVN, a key essential step in satiety, is prevented by blocking phospholipase C activation or Ca(2+) entry. These findings highlight an essential, and to our knowledge previously unknown, role for Ca(2+) signaling in the MC4R pathway that leads to satiety, and a novel non-redundant role for NCKX4-mediated Ca(2+) extrusion in controlling MC4R signaling and feeding behavior. Together, these findings highlight a novel pathway that potentially could be exploited to develop much needed new therapeutics to tackle eating disorders and obesity. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Allelic variants of melanocortin 3 receptor gene (MC3R and weight loss in obesity: a randomised trial of hypo-energetic high- versus low-fat diets.

Directory of Open Access Journals (Sweden)

José L Santos

Full Text Available INTRODUCTION: The melanocortin system plays an important role in energy homeostasis. Mice genetically deficient in the melanocortin-3 receptor gene have a normal body weight with increased body fat, mild hypophagia compared to wild-type mice. In humans, Thr6Lys and Val81Ile variants of the melanocortin-3 receptor gene (MC3R have been associated with childhood obesity, higher BMI Z-score and elevated body fat percentage compared to non-carriers. The aim of this study is to assess the association in adults between allelic variants of MC3R with weight loss induced by energy-restricted diets. SUBJECTS AND METHODS: This research is based on the NUGENOB study, a trial conducted to assess weight loss during a 10-week dietary intervention involving two different hypo-energetic (high-fat and low-fat diets. A total of 760 obese patients were genotyped for 10 single nucleotide polymorphisms covering the single exon of MC3R gene and its flanking regions, including the missense variants Thr6Lys and Val81Ile. Linear mixed models and haplotype-based analysis were carried out to assess the potential association between genetic polymorphisms and differential weight loss, fat mass loss, waist change and resting energy expenditure changes. RESULTS: No differences in drop-out rate were found by MC3R genotypes. The rs6014646 polymorphism was significantly associated with weight loss using co-dominant (p = 0.04 and dominant models (p = 0.03. These p-values were not statistically significant after strict control for multiple testing. Haplotype-based multivariate analysis using permutations showed that rs3827103-rs1543873 (p = 0.06, rs6014646-rs6024730 (p = 0.05 and rs3746619-rs3827103 (p = 0.10 displayed near-statistical significant results in relation to weight loss. No other significant associations or gene*diet interactions were detected for weight loss, fat mass loss, waist change and resting energy expenditure changes. CONCLUSION: The study

Coat colour phenotype of Qingyu pig is associated with polymorphisms of melanocortin receptor 1 gene.

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Wu, Xiaoqian; Tan, Zhendong; Shen, Linyuan; Yang, Qiong; Cheng, Xiao; Liao, Kun; Bai, Lin; Shuai, Surong; Li, Mingzhou; Li, Xuewei; Zhang, Shunhua; Zhu, Li

2017-07-01

Qingyu pig, a Chinese indigenous pig breed, exhibits two types of coat colour phenotypes, including pure black and white with black spotting respectively. Melanocortin receptor 1 ( MC1R ) and agouti signaling protein ( ASIP ) are two widely reported pivotal genes that significantly affect the regulation of coat colour. The objectives of this study were to investigate whether the polymorphisms of these two genes are associated with coat colour and analyze the molecular mechanism of the coat colour separation in Qingyu pig. We studied the phenotype segregation and used polymerase chain reaction amplification and Sanger sequencing to investigate the polymorphism of MC1R and ASIP in 121 Qingyu pigs, consisting of 115 black and 6 white with black spotted pigs. Coat colour of Qingyu pig is associated with the polymorphisms of MC1R but not ASIP . We only found 2 haplotypes, E QY and E qy , based on the 13 observed mutations from MC1R gene. Among which, E qy presented a recessive inheritance mode in black spotted Qingyu pigs. Further analysis revealed a g.462-463CC insertion that caused a frameshift mutation and a premature stop codon, thus changed the first transmembrane domain completely and lost the remaining six transmembrane domains. Altogether, our results strongly support that the variety of Qingyu pig's coat colour is related to MC1R . Our findings indicated that black coat colour in Qingyu pig was dominant to white with black spotted phenotype and MC1R gene polymorphism was associated with coat colour separation in Qingyu pig.

Coat colour phenotype of Qingyu pig is associated with polymorphisms of melanocortin receptor 1 gene

Directory of Open Access Journals (Sweden)

Xiaoqian Wu

2017-07-01

Full Text Available Objective Qingyu pig, a Chinese indigenous pig breed, exhibits two types of coat colour phenotypes, including pure black and white with black spotting respectively. Melanocortin receptor 1 (MC1R and agouti signaling protein (ASIP are two widely reported pivotal genes that significantly affect the regulation of coat colour. The objectives of this study were to investigate whether the polymorphisms of these two genes are associated with coat colour and analyze the molecular mechanism of the coat colour separation in Qingyu pig. Methods We studied the phenotype segregation and used polymerase chain reaction amplification and Sanger sequencing to investigate the polymorphism of MC1R and ASIP in 121 Qingyu pigs, consisting of 115 black and 6 white with black spotted pigs. Results Coat colour of Qingyu pig is associated with the polymorphisms of MC1R but not ASIP. We only found 2 haplotypes, EQY and Eqy, based on the 13 observed mutations from MC1R gene. Among which, Eqy presented a recessive inheritance mode in black spotted Qingyu pigs. Further analysis revealed a g.462–463CC insertion that caused a frameshift mutation and a premature stop codon, thus changed the first transmembrane domain completely and lost the remaining six transmembrane domains. Altogether, our results strongly support that the variety of Qingyu pig’s coat colour is related to MC1R. Conclusion Our findings indicated that black coat colour in Qingyu pig was dominant to white with black spotted phenotype and MC1R gene polymorphism was associated with coat colour separation in Qingyu pig.

Antibodies against the melanocortin-4 receptor act as inverse agonists in vitro and in vivo.

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Peter, Jean-Christophe; Nicholson, Janet R; Heydet, Déborah; Lecourt, Anne-Catherine; Hoebeke, Johan; Hofbauer, Karl G

2007-06-01

Functionally active antibodies (Abs) against central G-protein-coupled receptors have not yet been reported. We selected the hypothalamic melanocortin-4 receptor (MC4-R) as a target because of its crucial role in the regulation of energy homeostasis. A 15 amino acid sequence of the N-terminal (NT) domain was used as an antigen. This peptide showed functional activity in surface plasmon resonance experiments and in studies on HEK-293 cells overexpressing the human MC4-R (hMC4-R). Rats immunized against the NT peptide produced specific antibodies, which were purified and characterized in vitro. In HEK-293 cells, rat anti-NT Abs showed specific immunofluorescence labeling of hMC4-R. They reduced the production of cAMP under basal conditions and after stimulation with a synthetic MC4-R agonist. Rats immunized against the NT peptide developed a phenotype consistent with MC4-R blockade, that is, increased food intake and body weight, increased liver and fat pad weight, and elevated plasma triglycerides. In a separate experiment in rats, an increase in food intake could be produced after injection of purified Abs into the third ventricle. Similar results were obtained in rats injected with anti-NT Abs raised in rabbits. Our data show for the first time that active immunization of rats against the NT sequence of the MC4-R results in specific Abs, which appear to stimulate food intake by acting as inverse agonists in the hypothalamus.

The MC4 receptor and control of appetite

NARCIS (Netherlands)

Adan, R. A. H.; Tiesjema, B.; Hillebrand, J. J. G.; La Fleur, S. E.; Kas, M. J. H.; de Krom, M.

2006-01-01

Mutations in the human melanocortin (MC)4 receptor have been associated with obesity, which underscores the relevance of this receptor as a drug target to treat obesity. Infusion of MC4R agonists decreases food intake, whereas inhibition of MC receptor activity by infusion of an MC receptor

Modulation of melanocortin- induced changes in spinal nociception by µ-opioid receptor agonist and antagonist in neuropathic rats

NARCIS (Netherlands)

Gispen, W.H.; Starowitcz, K.; Przewlocki, R.; Przewlocka, B.

2002-01-01

Co-localization of opioid and melanocortin receptor expression, especially at the spinal cord level in the dorsal horn and in the gray matter surrounding the central canal led to the suggestion that melanocortins might play a role in nociceptive processes. In the present studies, we aimed to

Melanocortin-4 receptor messenger ribonucleic acid expression in rat cardiorespiratory, musculoskeletal, and integumentary systems.

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Mountjoy, Kathleen G; Jenny Wu, C-S; Dumont, Laurence M; Wild, J Martin

2003-12-01

We determined melanocortin-4 receptor (MC4-R) mRNA ontogeny in the rat using in situ hybridization and a rat MC4-R riboprobe and showed numerous peripheral sites of expression for MC4-R. The developing heart showed MC4-R mRNA expression as early as embryonic day (E) 14. In the lungs of E16-E20 fetuses, the cells surrounding developing bronchi expressed relatively strong in situ signal. Muscles associated with the respiratory system such as diaphragm and intercostal muscle expressed MC4-R mRNA as early as E14. Occipital and tongue muscles, in particular the genioglossus, showed diffuse signal at E15-E20. In the eye, a discrete signal was detected in an outer neuroblastic layer which may correspond to retina or extraocular muscle. Developing limb buds expressed relatively strong signal at E14, whereas skull bone and joint capsules of the paw of the forelimb showed signal at E18-E20. Using RT-PCR and ribonuclease protection assays, we determined that MC4-R mRNA is also expressed in adult rat heart, lung, kidney, and testis. The expression of the MC4-R in cardiorespiratory, musculoskeletal, and integumentary systems supports functional roles for the MC4-R in addition to its roles in appetite, weight control, and regulation of linear growth.

Design, synthesis, and testing of multivalent compounds targeted to melanocortin receptors

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Dehigaspitiya, Dilani Chathurika

Our focus is on developing non-invasive molecular imaging reagents, which target human cancers that presently are difficult to detect, such as melanoma. We wish to apply the multivalency concept to differentiate between healthy cells and melanoma cells. Melanoma cells are known to over-express alpha melanocyte stimulating hormone receptors. A successful multivalent construct should show greater avidity towards melanoma cells than healthy cells due to the synergistic effects arising from multivalency. Both oligomeric and shorter linear constructs bearing the minimum active sequence of melanocyte stimulating hormone, His-DPhe-Arg-Trp-NH2(MSH4), which binds with low micromolar affinity to alpha melanocyte stimulating hormone receptors, were synthesized. Binding affinities of these constructs were evaluated in a competitive binding assay by competing with labeled ligands, Eu-DTPA-PEGO-MSH7 and/or Eu-DTPA-PEGO-NDP-alpha-MSH on the engineered cell line HEK293 CCK2R/hMC4R, which is genetically modified to over-express both the cholecystokinin 2 receptor (CCK2R) and human melanocortin 4 receptor (hMC4R). The oligomers were rapidly assembled using microwave-assisted copper catalyzed azide-alkyne cycloaddition between a dialkyne derivative of MSH4 and a diazide derivative of (Pro-Gly)3 as co-monomers. Three oligomer mixtures were further analyzed based on their degree of oligomerization and the route by which the MSH4 monomers were oligomerized, protected vs deprotected. Completive binding assay against Eu-DTPA-PEGO-MSH7 showed only a statistical enhancement of binding when calculated based on the total MSH4 concentration. However, when the calculation of avidity is based on an estimation of the particles numbers, there was a seven times enhancement of binding compared to a monovalent MSH4 control. The shorter linear multivalent MSH4 constructs were synthesized using ethylene glycol, glycerol, and mannitol as core scaffolds with maximum inter-ligand distances ranging from 27

A missense mutation in melanocortin 1 receptor is associated with the red coat colour in donkeys.

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Abitbol, M; Legrand, R; Tiret, L

2014-12-01

The seven donkey breeds recognised by the French studbook are characterised by few coat colours: black, bay and grey. Normand bay donkeys seldom give birth to red foals, a colour more commonly seen and recognised in American miniature donkeys. Red resembles the equine chestnut colour, previously attributed to a mutation in the melanocortin 1 receptor gene (MC1R). We used a panel of 124 donkeys to identify a recessive missense c.629T>C variant in MC1R that showed a perfect association with the red coat colour. This variant leads to a methionine to threonine substitution at position 210 in the protein. We showed that methionine 210 is highly conserved among vertebrate melanocortin receptors. Previous in silico and in vitro analyses predicted this residue to lie within a functional site. Our in vivo results emphasised the pivotal role played by this residue, the alteration of which yielded a phenotype fully compatible with a loss of function of MC1R. We thus propose to name the c.629T>C allele in donkeys the e allele, which further enlarges the panel of recessive MC1R loss-of-function alleles described in animals and humans. © 2014 Stichting International Foundation for Animal Genetics.

N-terminal fatty acylated His-dPhe-Arg-Trp-NH(2) tetrapeptides: influence of fatty acid chain length on potency and selectivity at the mouse melanocortin receptors and human melanocytes.

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Todorovic, Aleksandar; Holder, Jerry Ryan; Bauzo, Rayna M; Scott, Joseph Walker; Kavanagh, Renny; Abdel-Malek, Zalfa; Haskell-Luevano, Carrie

2005-05-05

The melanocortin system is involved in the regulation of a diverse number of physiologically important pathways including pigmentation, feeding behavior, weight and energy homeostasis, inflammation, and sexual function. All the endogenous melanocortin agonist ligands possess the conserved His-Phe-Arg-Trp tetrapeptide sequence that is postulated to be important for melanocortin receptor molecular recognition and stimulation. Previous studies by our laboratory resulted in the discovery that increasing alkyl chain length at the N-terminal "capping" region of the His-dPhe-Arg-Trp-NH(2) tetrapeptide resulted in a 100-fold increased melanocortin receptor agonist potency. This study was undertaken to systematically evaluate the pharmacological effects of increasing N-capping alkyl chain length of the CH(3)(CH(2))(n)CO-His-dPhe-Arg-Trp-NH(2) (n = 6-16) tetrapeptide template. Twelve analogues were synthesized and pharmacologically characterized at the mouse melanocortin receptors MC1R and MC3R-MC5R and human melanocytes known to express the MC1R. These peptides demonstrated melanocortin receptor selectivity profiles different from those of previously published tetrapeptides. The most notable results of enhanced ligand potency (20- to 200-fold) and receptor selectivity were observed at the MC1R. Tetrapeptides that possessed greater than nine alkyl groups were superior to alpha-MSH in terms of the stimulation of human melanocyte tyrosinase activity. Additionally, the n-pentadecanoyl derivative had a residual effect on tyrosinase activity that existed for at least 4 days after the peptide was removed from the human melanocyte culture medium. These data demonstrate the utility, potency, and residual effect of melanocortin tetrapeptides by adding N-terminal fatty acid moieties.

Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

Energy Technology Data Exchange (ETDEWEB)

Kim, Nam Soo; Kim, Yoon-Jin [Department of Biology, Research Institute for Basic Science, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Cho, Si Young [R and D Center, Amore Pacific Corporation, Yongin-si, Gyeonggi-do 446-729 (Korea, Republic of); Lee, Tae Ryong, E-mail: trlee@amorepacific.com [R and D Center, Amore Pacific Corporation, Yongin-si, Gyeonggi-do 446-729 (Korea, Republic of); Kim, Sang Hoon, E-mail: shkim@khu.ac.kr [Department of Biology, Research Institute for Basic Science, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

2013-09-27

Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putative peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes.

Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

International Nuclear Information System (INIS)

Kim, Nam Soo; Kim, Yoon-Jin; Cho, Si Young; Lee, Tae Ryong; Kim, Sang Hoon

2013-01-01

Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putative peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes

Assessment of polymorphic variants in the melanocortin-1 receptor gene with cutaneous pigmentation using an evolutionary approach.

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Kanetsky, Peter A; Ge, Fan; Najarian, Derek; Swoyer, Jennifer; Panossian, Saarene; Schuchter, Lynn; Holmes, Robin; Guerry, DuPont; Rebbeck, Timothy R

2004-05-01

The melanocortin-1 receptor gene (MC1R) encodes a membrane-bound receptor protein that is central to melanin synthesis. The coding region of MC1R is highly polymorphic and associations of variants with pigmentation phenotypes and risk for cutaneous neoplasms have been reported. We sought to determine the distribution and frequency of MC1R variants and their relationship to pigmentation characteristics in 179 Caucasian controls from the United States. One hundred thirty-five (75.4%) subjects carried one or more variants, and we determined that carriage of the previously designated "red hair color" (RHC) alleles, R151C, R160W, and D294H was strongly associated with fair pigmentation phenotypes including light hair and eye color, tendency to burn, decreased tendency to tan, and freckling. We used SIFT software to define MC1R protein positions that were predicted intolerant to amino acid substitutions; detected variants that corresponded to intolerant substitutions were D84E, R142H, R151C, I155T, R160W, and D294H. Carriage of one or more of these putative functionally important variants or the frameshift variant ins86A was significantly associated with fair pigmentation phenotypes. Analyses limited to carriage of ins86A and the three non-RHC alleles identified by SIFT were attenuated and no longer reached statistical significance. This is the first study to describe MC1R variants among control subjects from the U.S. Our results indicate that the frequency of variants is similar to that previously observed among non-U.S. Caucasians. Risk variants defined by either the published literature or by evolutionary criteria are strongly and significantly associated with all fair pigmentation phenotypes that were measured.

Synthesis and Pharmacology of α/β(3)-Peptides Based on the Melanocortin Agonist Ac-His-dPhe-Arg-Trp-NH2 Sequence.

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Singh, Anamika; Tala, Srinivasa R; Flores, Viktor; Freeman, Katie; Haskell-Luevano, Carrie

2015-05-14

The melanocortin-3 and -4 receptors are expressed in the brain and play key roles in regulating feeding behavior, metabolism, and energy homeostasis. In the present study, incorporation of β(3)-amino acids into a melanocortin tetrapeptide template was investigated. Four linear α/β(3)-hybrid tetrapeptides were designed with the modifications at the Phe, Arg, and Trp residues in the agonist sequence Ac-His-dPhe-Arg-Trp-NH2. The most potent mouse melanocortin-4 receptor (mMC4R) agonist, Ac-His-dPhe-Arg-β(3)hTrp-NH2 (8) showed 35-fold selectivity versus the mMC3R. The study presented here has identified a new template with heterogeneous backbone for designing potent and selective melanocortin receptor ligands.

Synthesis and Pharmacology of α/β3-Peptides Based on the Melanocortin Agonist Ac-His-dPhe-Arg-Trp-NH2 Sequence

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2015-01-01

The melanocortin-3 and -4 receptors are expressed in the brain and play key roles in regulating feeding behavior, metabolism, and energy homeostasis. In the present study, incorporation of β3-amino acids into a melanocortin tetrapeptide template was investigated. Four linear α/β3-hybrid tetrapeptides were designed with the modifications at the Phe, Arg, and Trp residues in the agonist sequence Ac-His-dPhe-Arg-Trp-NH2. The most potent mouse melanocortin-4 receptor (mMC4R) agonist, Ac-His-dPhe-Arg-β3hTrp-NH2 (8) showed 35-fold selectivity versus the mMC3R. The study presented here has identified a new template with heterogeneous backbone for designing potent and selective melanocortin receptor ligands. PMID:26005535

Role of Hypothalamic Melanocortin System in Adaptation of Food Intake to Food Protein Increase in Mice

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Pillot, Bruno; Duraffourd, Céline; Bégeot, Martine; Joly, Aurélie; Luquet, Serge; Houberdon, Isabelle; Naville, Danielle; Vigier, Michèle; Gautier-Stein, Amandine; Magnan, Christophe; Mithieux, Gilles

2011-01-01

The hypothalamic melanocortin system—the melanocortin receptor of type 4 (MC4R) and its ligands: α-melanin-stimulating hormone (α-MSH, agonist, inducing hypophagia), and agouti-related protein (AgRP, antagonist, inducing hyperphagia)—is considered to play a central role in the control of food intake. We tested its implication in the mediation of the hunger-curbing effects of protein-enriched diets (PED) in mice. Whereas there was a 20% decrease in food intake in mice fed on the PED, compared to mice fed on an isocaloric starch-enriched diet, there was a paradoxical decrease in expression of the hypothalamic proopiomelanocortin gene, precursor of α-MSH, and increase in expression of the gene encoding AgRP. The hypophagia effect of PED took place in mice with invalidation of either MC4R or POMC, and was even strengthened in mice with ablation of the AgRP-expressing neurons. These data strongly suggest that the hypothalamic melanocortin system does not mediate the hunger-curbing effects induced by changes in the macronutrient composition of food. Rather, the role of this system might be to defend the body against the variations in food intake generated by the nutritional environment. PMID:21544212

Role of hypothalamic melanocortin system in adaptation of food intake to food protein increase in mice.

Directory of Open Access Journals (Sweden)

Bruno Pillot

Full Text Available The hypothalamic melanocortin system--the melanocortin receptor of type 4 (MC4R and its ligands: α-melanin-stimulating hormone (α-MSH, agonist, inducing hypophagia, and agouti-related protein (AgRP, antagonist, inducing hyperphagia--is considered to play a central role in the control of food intake. We tested its implication in the mediation of the hunger-curbing effects of protein-enriched diets (PED in mice. Whereas there was a 20% decrease in food intake in mice fed on the PED, compared to mice fed on an isocaloric starch-enriched diet, there was a paradoxical decrease in expression of the hypothalamic proopiomelanocortin gene, precursor of α-MSH, and increase in expression of the gene encoding AgRP. The hypophagia effect of PED took place in mice with invalidation of either MC4R or POMC, and was even strengthened in mice with ablation of the AgRP-expressing neurons. These data strongly suggest that the hypothalamic melanocortin system does not mediate the hunger-curbing effects induced by changes in the macronutrient composition of food. Rather, the role of this system might be to defend the body against the variations in food intake generated by the nutritional environment.

1,2,3-Triazole Rings as a Disulfide Bond Mimetic in Chimeric AGRP-Melanocortin Peptides: Design, Synthesis, and Functional Characterization.

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Tala, Srinivasa R; Singh, Anamika; Lensing, Cody J; Schnell, Sathya M; Freeman, Katie T; Rocca, James R; Haskell-Luevano, Carrie

2018-05-16

The melanocortin system is involved in the regulation of complex physiological functions, including energy and weight homeostasis, feeding behavior, inflammation, sexual function, pigmentation, and exocrine gland function. The five melanocortin receptors that belong to the superfamily of G protein-coupled receptors (GPCRs) are regulated by endogenously expressed agonists and antagonists. The aim of this study was to explore the potential of replacing the disulfide bridge in chimeric AGRP-melanocortin peptide Tyr-c[Cys-His-d-Phe-Arg-Trp-Asn-Ala-Phe-Cys]-Tyr-NH 2 (1) with 1,2,3-triazole moieties. A series of 1,2,3-triazole-bridged peptidomimetics were designed, synthesized, and pharmacologically evaluated at the mouse melanocortin receptors. The ligands possessed nanomolar to micromolar agonist cAMP signaling potency. A key finding was that the disulfide bond in peptide 1 can be replaced with the monotriazole ring with minimal effect on the functional activity at the melanocortin receptors. The 1,5-disubstituted triazole-bridged peptide 6 showed equipotent functional activity at the mMC3R and modest 5-fold decreased agonist potency at the mMC4R compared to those of 1. Interestingly, the 1,4- and 1,5-disubstituted isomers of the triazole ring resulted in different selectivities at the receptor subtypes, indicating subtle structural features that may be exploited in the generation of selective melanocortin ligands. Introducing cyclic and acyclic bis-triazole moieties into chimeric AGRP template 1 generally decreased agonist activity. These results will be useful for the further design of neuronal chemical probes for the melanocortin receptors as well as in other receptor systems.

Melanocortin Tetrapeptide Ac-His-DPhe-Arg-Trp-NH2 Modified at the Para Position of the Benzyl Side Chain (DPhe): Importance for Mouse Melanocortin-3 Receptor Agonist versus Antagonist Activity

OpenAIRE

Proneth, Bettina; Pogozheva, Irina D.; Portillo, Federico P.; Mosberg, Henry I.; Haskell-Luevano, Carrie

2008-01-01

The melanocortin-3 and -4 receptors (MC3R, MC4R) have been implicated in energy homeostasis and obesity. Whereas the physiological role of the MC4R is extensively studied, little is known about the MC3R. One caveat is the limited availability of ligands that are selective for the MC3R. Previous studies identified Ac-His-DPhe(p-I)-Arg-Trp-NH2, which possessed partial agonist/antagonist pharmacology at the mMC3R while retaining full nanomolar agonist pharmacology at the mMC4R. These data allowe...

Synthesis and characterization of a Eu-DTPA-PEGO-MSH(4) derivative for evaluation of binding of multivalent molecules to melanocortin receptors.

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Xu, Liping; Vagner, Josef; Alleti, Ramesh; Rao, Venkataramanarao; Jagadish, Bhumasamudram; Morse, David L; Hruby, Victor J; Gillies, Robert J; Mash, Eugene A

2010-04-15

A labeled variant of MSH(4), a tetrapeptide that binds to the human melanocortin 4 receptor (hMC4R) with low microM affinity, was prepared by solid-phase synthesis methods, purified, and characterized. The labeled ligand, Eu-DTPA-PEGO-His-dPhe-Arg-Trp-NH(2), exhibited a K(d) for hMC4R of 9.1+/-1.4 microM, approximately 10-fold lower affinity than the parental ligand. The labeled MSH(4) derivative was employed in a competitive binding assay to characterize the interactions of hMC4R with monovalent and divalent MSH(4) constructs derived from squalene. The results were compared with results from a similar assay that employed a more potent labeled ligand, Eu-DTPA-NDP-alpha-MSH. While results from the latter assay reflected only statistical effects, results from the former assay reflected a mixture of statistical, proximity, and/or cooperative binding effects. Copyright 2010 Elsevier Ltd. All rights reserved.

Synthesis and characterization of time-resolved fluorescence probes for evaluation of competitive binding to melanocortin receptors.

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Alleti, Ramesh; Vagner, Josef; Dehigaspitiya, Dilani Chathurika; Moberg, Valerie E; Elshan, N G R D; Tafreshi, Narges K; Brabez, Nabila; Weber, Craig S; Lynch, Ronald M; Hruby, Victor J; Gillies, Robert J; Morse, David L; Mash, Eugene A

2013-09-01

Probes for use in time-resolved fluorescence competitive binding assays at melanocortin receptors based on the parental ligands MSH(4), MSH(7), and NDP-α-MSH were prepared by solid phase synthesis methods, purified, and characterized. The saturation binding of these probes was studied using HEK-293 cells engineered to overexpress the human melanocortin 4 receptor (hMC4R) as well as the human cholecystokinin 2 receptor (hCCK2R). The ratios of non-specific binding to total binding approached unity at high concentrations for each probe. At low probe concentrations, receptor-mediated binding and uptake was discernable, and so probe concentrations were kept as low as possible in determining Kd values. The Eu-DTPA-PEGO-MSH(4) probe exhibited low specific binding relative to non-specific binding, even at low nanomolar concentrations, and was deemed unsuitable for use in competition binding assays. The Eu-DTPA-PEGO probes based on MSH(7) and NDP-α-MSH exhibited Kd values of 27±3.9nM and 4.2±0.48nM, respectively, for binding with hMC4R. These probes were employed in competitive binding assays to characterize the interactions of hMC4R with monovalent and divalent MSH(4), MSH(7), and NDP-α-MSH constructs derived from squalene. Results from assays with both probes reflected only statistical enhancements, suggesting improper ligand spacing on the squalene scaffold for the divalent constructs. The Ki values from competitive binding assays that employed the MSH(7)-based probe were generally lower than the Ki values obtained when the probe based on NDP-α-MSH was employed, which is consistent with the greater potency of the latter probe. The probe based on MSH(7) was also competed with monovalent, divalent, and trivalent MSH(4) constructs that previously demonstrated multivalent binding in competitive binding assays against a variant of the probe based on NDP-α-MSH. Results from these assays confirm multivalent binding, but suggest a more modest increase in avidity for these

Statistical and biological gene-lifestyle interactions of MC4R and FTO with diet and physical activity on obesity: new effects on alcohol consumption

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Fat mass and obesity (FTO) and melanocortin-4 receptor (MC4R) and are relevant genes associated with obesity. This could be through food intake, but results are contradictory. Modulation by diet or other lifestyle factors is also not well understood. To investigate whether MC4R and FTO associations ...

Melanocortin Receptor Agonists Facilitate Oxytocin-Dependent Partner Preference Formation in the Prairie Vole.

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Modi, Meera E; Inoue, Kiyoshi; Barrett, Catherine E; Kittelberger, Kara A; Smith, Daniel G; Landgraf, Rainer; Young, Larry J

2015-07-01

The central melanocortin (MC) system has been widely studied for its effects on food intake and sexual behavior. However, the MC system, and more specifically the MC4 receptor (MC4R), also interacts with neurochemical systems that regulate socioemotional behaviors, including oxytocin (OT) and dopamine. In monogamous prairie voles, OT and dopamine interact to promote partner preference formation, a laboratory measure of an enduring social bond between mates. Here we investigated the effects of MC receptor activation on partner preference formation in prairie voles, as well as the interaction between the MC and OT systems during this process. Peripheral administration of the brain penetrant MC3/4R receptor peptide agonist, Melanotan II (MTII), and the highly selective, small-molecule MC4R agonist, Pf-446687, enhanced partner preference formation in the prairie vole, but not in the non-monogamous meadow vole. MTII-induced partner preferences were enduring, as they were present 1 week after drug manipulation. The prosocial effects of MCR agonists may be mediated, in part, through modulation of OT, as coadministration of an OT receptor antagonist prevented MTII-induced partner preferences. MTII also selectively activated hypothalamic OT neurons and potentiated central OT release. As OT has been shown to enhance some aspects of social cognition in humans, our data suggest that the MC4R may be a viable therapeutic target for enhancing social function in psychiatric disorders, including autism spectrum disorders and schizophrenia, potentially through activation of the OT system.

RM-493, a melanocortin-4 receptor (MC4R) agonist, increases resting energy expenditure in obese individuals.

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Chen, Kong Y; Muniyappa, Ranganath; Abel, Brent S; Mullins, Katherine P; Staker, Pamela; Brychta, Robert J; Zhao, Xiongce; Ring, Michael; Psota, Tricia L; Cone, Roger D; Panaro, Brandon L; Gottesdiener, Keith M; Van der Ploeg, Lex H T; Reitman, Marc L; Skarulis, Monica C

2015-04-01

Activation of the melanocortin-4 receptor (MC4R) with the synthetic agonist RM-493 decreases body weight and increases energy expenditure (EE) in nonhuman primates. The effects of MC4R agonists on EE in humans have not been examined to date. In a randomized, double-blind, placebo-controlled, crossover study, we examined the effects of the MC4R agonist RM-493 on resting energy expenditure (REE) in obese subjects in an inpatient setting. Twelve healthy adults (6 men and 6 women) with body mass index of 35.7 ± 2.9 kg/m(2) (mean ± SD) received RM-493 (1 mg/24 h) or placebo by continuous subcutaneous infusion over 72 hours, followed immediately by crossover to the alternate treatment. All subjects received a weight-maintenance diet (50% carbohydrate, 30% fat, and 20% protein) and performed 30 minutes of standardized exercise daily. Continuous EE was measured on the third treatment day in a room calorimeter, and REE in the fasting state was defined as the mean of 2 30-minute resting periods. RM-493 increased REE vs placebo by 6.4% (95% confidence interval, 0.68-13.02%), on average by 111 kcal/24 h (95% confidence interval, 15-207 kcal, P = .03). Total daily EE trended higher, whereas the thermic effect of a test meal and exercise EE did not differ significantly. The 23-hour nonexercise respiratory quotient was lower during RM-493 treatment (0.833 ± 0.021 vs 0.848 ± 0.022, P = .02). No adverse effect on heart rate or blood pressure was observed. Short-term administration of the MC4R agonist RM-493 increases REE and shifts substrate oxidation to fat in obese individuals.

Melanocortin tetrapeptide Ac-His-DPhe-Arg-Trp-NH2 modified at the para position of the benzyl side chain (DPhe): importance for mouse melanocortin-3 receptor agonist versus antagonist activity.

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Proneth, Bettina; Pogozheva, Irina D; Portillo, Federico P; Mosberg, Henry I; Haskell-Luevano, Carrie

2008-09-25

The melanocortin-3 and -4 receptors (MC3R, MC4R) have been implicated in energy homeostasis and obesity. Whereas the physiological role of the MC4R is extensively studied, little is known about the MC3R. One caveat is the limited availability of ligands that are selective for the MC3R. Previous studies identified Ac-His-DPhe(p-I)-Arg-Trp-NH 2, which possessed partial agonist/antagonist pharmacology at the mMC3R while retaining full nanomolar agonist pharmacology at the mMC4R. These data allowed for the hypothesis that the DPhe position in melanocortin tetrapeptides can be used to examine ligand side-chain determinants important for differentiation of mMC3R agonist versus antagonist activity. A series of 15 DPhe (7) modified Ac-His-DPhe (7)-Arg-Trp-NH 2 tetrapeptides has been synthesized and pharmacologically characterized. Most notable results include the identification of modifications that resulted in potent antagonists/partial agonists at the mMC3R and full, potent agonists at the mMC4R. These SAR studies provide experimental evidence that the molecular mechanism of antagonism at the mMC3R differentiates this subtype from the mMC4R.

Melanocortin-4 receptor activation stimulates hypothalamic brain-derived neurotrophic factor release to regulate food intake, body temperature and cardiovascular function.

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Nicholson, J R; Peter, J-C; Lecourt, A-C; Barde, Y-A; Hofbauer, K G

2007-12-01

In the present study, we aimed to investigate the neuromodulatory role played by hypothalamic brain-derived neurotrophic factor (BDNF) in the regulation of acute cardiovascular and feeding responses to melanocortin-4 receptor (MC4R) activation. In vitro, a selective MC4R agonist, MK1, stimulated BDNF release from isolated rat hypothalami and this effect was blocked by preincubation with the MC3/4R antagonist SHU-9119. In vivo, peripheral administration of MK1 decreased food intake in rats and this effect was blocked by pretreatment with an anti-BDNF antibody administered into the third ventricle. When anorexia was induced with the cannabinoid-1 receptor (CB1R) antagonist AM251, the anti-BDNF antibody did not prevent the reduction in food intake. Peripheral administration of MK1 also increased mean arterial pressure, heart rate and body temperature. These effects were prevented by pretreatment with the anti-BDNF antibody whereas the intracerebroventricular administration of BDNF caused changes similar to those of MK1. These findings demonstrate for the first time that activation of MC4R leads to an acute release of BDNF in the hypothalamus. This release is a prerequisite for MC4R-induced effects on appetite, body temperature and cardiovascular function. By contrast, CB1R antagonist-mediated anorexia is independent of the MC4R/BDNF pathway. Overall, these results show that BDNF is an important downstream mediator of the MC4R pathway.

Design of a new peptidomimetic agonist for the melanocortin receptors based on the solution structure of the peptide ligand, Ac-Nle-cyclo[Asp-Pro-DPhe-Arg-Trp-Lys]-NH(2).

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Fotsch, Christopher; Smith, Duncan M; Adams, Jeffrey A; Cheetham, Janet; Croghan, Michael; Doherty, Elizabeth M; Hale, Clarence; Jarosinski, Mark A; Kelly, Michael G; Norman, Mark H; Tamayo, Nuria A; Xi, Ning; Baumgartner, James W

2003-07-21

The solution structure of a potent melanocortin receptor agonist, Ac-Nle-cyclo[Asp-Pro-DPhe-Arg-Trp-Lys]-NH(2) (1) was calculated using distance restraints determined from 1H NMR spectroscopy. Eight of the lowest energy conformations from this study were used to identify non-peptide cores that mimic the spatial arrangement of the critical tripeptide region, DPhe-Arg-Trp, found in 1. From these studies, compound 2a, containing the cis-cyclohexyl core, was identified as a functional agonist of the melanocortin-4 receptor (MC4R) with an IC(50) and EC(50) below 10 nM. Compound 2a also showed 36- and 7-fold selectivity over MC3R and MC1R, respectively, in the binding assays. Subtle changes in cyclohexane stereochemistry and removal of functional groups led to analogues with lower affinity for the MC receptors.

Structure-activity relationship of linear tetrapeptides Tic-DPhe-Arg-Trp-NH2 at the human melanocortin-4 receptor and effects on feeding behaviors in rat.

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Ye, Zhixiong; MacNeil, Tanya; Weinberg, David H; Kalyani, Rubana N; Tang, Rui; Strack, Alison M; Murphy, Beth A; Mosley, Ralph T; Euan MacIntyre, D; Van der Ploeg, Lex H T; Patchett, Arthur A; Wyvratt, Matthew J; Nargund, Ravi P

2005-10-01

The melanocortin subtype-4 receptor (MC4R) has been implicated in the control of feeding behavior and body weight regulation. A series of tetrapeptides, based on Tic-DPhe-Arg-Trp-NH2-a mimic of the putative message sequence "His-Phe-Arg-Trp" and modified at the DPhe position, were prepared and pharmacologically characterized for potency and selectivity. Substitution of His with Tic gave peptides with significant increases in selectivity. The effects of the substitution pattern of DPhe were investigated and it has significant influences on potency and the level of the maximum cAMP accumulation. Intracerebroventricular administration of peptide 10 induced significant inhibition of cumulative overnight food intake and feeding duration in rats.

Melanocortin-3 receptors in the limbic system mediate feeding-related motivational responses during weight loss

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Maria Mavrikaki

2016-07-01

Full Text Available Objective: Appetitive responses to weight loss are mediated by a nutrient-sensing neural network comprised of melanocortin neurons. The role of neural melanocortin-3 receptors (MC3R in mediating these responses is enigmatic. Mc3r knockout mice exhibit a paradoxical phenotype of obesity and reduced feeding-related behaviors in situations of nutrient scarcity. Here we examined whether MC3Rs expressed in mesolimbic neurons regulate feeding-related motivational responses. Methods: Interactions between Mc3r genotype, cognitive function and energy balance on food self-administration were assessed using operant conditioning with fixed- and progressive ratio (FR1/PR1 settings. Inhibition of Mc3r transcription by a loxP-flanked transcriptional blocker (TB in C57BL/6JN mice (Mc3rTB/TB was reversed in mesolimbic neurons using DAT-Cre (DAT-MC3R. Results: Caloric restriction (CR caused 10–15% weight loss and increased motivation to acquire food rewards during training sessions. c-Fos-expression in the nucleus accumbens was increased 1 h following food presentation. While exhibiting weight loss, total food self-administration, enhanced motivation to self-administer food rewards in training sessions held during CR and c-Fos-activation in the nucleus accumbens following re-feeding were all markedly attenuated in Mc3rTB/TB mice. In contrast, cognitive abilities were normal in Mc3rTB/TB mice. Total food self-administration during FR1 sessions was not rescued in DAT-MC3R mice, however enhanced motivational responses to self-administer food rewards in PR1 conditions were restored. The nutrient-partitioning phenotype observed with Mc3r-deficiency was not rescued in DAT-MC3R mice. Conclusions: Mesolimbic MC3Rs mediate enhanced motivational responses during CR. However, they are insufficient to restore normal caloric loading when food is presented during CR and do not affect metabolic conditions altering nutrient partitioning. Author Video: Author Video Watch what

Early childhood BMI trajectories in monogenic obesity due to leptin, leptin receptor, and melanocortin 4 receptor deficiency.

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Kohlsdorf, Katja; Nunziata, Adriana; Funcke, Jan-Bernd; Brandt, Stephanie; von Schnurbein, Julia; Vollbach, Heike; Lennerz, Belinda; Fritsch, Maria; Greber-Platzer, Susanne; Fröhlich-Reiterer, Elke; Luedeke, Manuel; Borck, Guntram; Debatin, Klaus-Michael; Fischer-Posovszky, Pamela; Wabitsch, Martin

2018-02-27

To evaluate whether early childhood body mass index (BMI) is an appropriate indicator for monogenic obesity. A cohort of n = 21 children living in Germany or Austria with monogenic obesity due to congenital leptin deficiency (group LEP, n = 6), leptin receptor deficiency (group LEPR, n = 6) and primarily heterozygous MC4 receptor deficiency (group MC4R, n = 9) was analyzed. A control group (CTRL) was defined that consisted of n = 22 obese adolescents with no mutation in the above mentioned genes. Early childhood (0-5 years) BMI trajectories were compared between the groups at selected time points. The LEP and LEPR group showed a tremendous increase in BMI during the first 2 years of life with all patients displaying a BMI >27 kg/m 2 (27.2-38.4 kg/m 2 ) and %BMI P95 (percentage of the 95th percentile BMI for age and sex) >140% (144.8-198.6%) at the age of 2 years and a BMI > 33 kg/m 2 (33.3-45.9 kg/m 2 ) and %BMI P95  > 184% (184.1-212.6%) at the age of 5 years. The MC4R and CTRL groups had a later onset of obesity with significantly lower BMI values at both time points (p BMI trajectories in this pediatric cohort with monogenic obesity we suggest that BMI values >27.0 kg/m 2 or %BMI P95  > 140% at the age of 2 years and BMI values >33.0 kg/m 2 or %BMI P95  > 184% at the age of 5 years may be useful cut points to identify children who should undergo genetic screening for monogenic obesity due to functionally relevant mutations in the leptin gene or leptin receptor gene.

Identification of Tetrapeptides from a Mixture Based Positional Scanning Library That Can Restore nM Full Agonist Function of the L106P, I69T, I102S, A219V, C271Y, and C271R Human Melanocortin-4 Polymorphic Receptors (hMC4Rs)

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Haslach, Erica M.; Huang, Huisuo; Dirain, Marvin; Debevec, Ginamarie; Geer, Phaedra; Santos, Radleigh G.; Giulianotti, Marc A.; Pinilla, Clemencia; Appel, Jon R.; Doering, Skye R.; Walters, Michael A.; Houghten, Richard A.; Haskell-Luevano, Carrie

2014-01-01

Human obesity has been linked to genetic factors and single nucleotide polymorphisms (SNPs). Melanocortin-4 receptor (MC4R) SNPs have been associated with up to 6% frequency in morbidly obese children and adults. A potential therapy for individuals possessing such genetic modifications is the identification of molecules that can restore proper receptor signaling and function. These compounds could serve as personalized medications improving quality of life issues as well as alleviating diseas...

Application of a novel design paradigm to generate general nonpeptide combinatorial templates mimicking beta-turns: synthesis of ligands for melanocortin receptors.

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Webb, Thomas R; Jiang, Luyong; Sviridov, Sergey; Venegas, Ruben E; Vlaskina, Anna V; McGrath, Douglas; Tucker, John; Wang, Jian; Deschenes, Alain; Li, Rongshi

2007-01-01

We report the further application of a novel approach to template and ligand design by the synthesis of agonists of the melanocortin receptor. This design method uses the conserved structural data from the three-dimensional conformations of beta-turn peptides to design rigid nonpeptide templates that mimic the orientation of the main chain C-alpha atoms in a peptide beta-turn. We report details on a new synthesis of derivatives of template 1 that are useful for the synthesis of exploratory libraries. The utility of this technique is further exemplified by several iterative rounds of high-throughput synthesis and screening, which result in new partially optimized nonpeptide agonists for several melanocortin receptors.

Anxiolytic-like and antidepressant-like activities of MCL0129 (1-[(S)-2-(4-fluorophenyl)-2-(4-isopropylpiperadin-1-yl)ethyl]-4-[4-(2-methoxynaphthalen-1-yl)butyl]piperazine), a novel and potent nonpeptide antagonist of the melanocortin-4 receptor.

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Chaki, Shigeyuki; Hirota, Shiho; Funakoshi, Takeo; Suzuki, Yoshiko; Suetake, Sayoko; Okubo, Taketoshi; Ishii, Takaaki; Nakazato, Atsuro; Okuyama, Shigeru

2003-02-01

We investigated the effects of a novel melanocortin-4 (MC4) receptor antagonist,1-[(S)-2-(4-fluorophenyl)-2-(4-isopropylpiperadin-1-yl)ethyl]-4-[4-(2-methoxynaphthalen-1-yl)butyl]piperazine (MCL0129) on anxiety and depression in various rodent models. MCL0129 inhibited [(125)I][Nle(4)-D-Phe(7)]-alpha-melanocyte-stimulating hormone (alpha-MSH) binding to MC4 receptor with a K(i) value of 7.9 nM, without showing affinity for MC1 and MC3 receptors. MCL0129 at 1 microM had no apparent affinity for other receptors, transporters, and ion channels related to anxiety and depression except for a moderate affinity for the sigma(1) receptor, serotonin transporter, and alpha(1)-adrenoceptor, which means that MCL0129 is selective for the MC4 receptor. MCL0129 attenuated the alpha-MSH-increased cAMP formation in COS-1 cells expressing the MC4 receptor, whereas MCL0129 did not affect basal cAMP levels, thereby indicating that MCL0129 acts as an antagonist at the MC4 receptor. Swim stress markedly induced anxiogenic-like effects in both the light/dark exploration task in mice and the elevated plus-maze task in rats, and MCL0129 reversed the stress-induced anxiogenic-like effects. Under nonstress conditions, MCL0129 prolonged time spent in the light area in the light/dark exploration task and suppressed marble-burying behavior. MCL0129 shortened immobility time in the forced swim test and reduced the number of escape failures in inescapable shocks in the learned helplessness test, thus indicating an antidepressant potential. In contrast, MCL0129 had negligible effects on spontaneous locomotor activity, Rotarod performance, and hexobarbital-induced anesthesia. These observations indicate that MCL0129 is a potent and selective MC4 antagonist with anxiolytic- and antidepressant-like activities in various rodent models. MC4 receptor antagonists may prove effective for treating subjects with stress-related disorders such as depression and/or anxiety.

The melanocortin receptor agonist NDP-MSH impairs the allostimulatory function of dendritic cells.

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Rennalls, La'Verne P; Seidl, Thomas; Larkin, James M G; Wellbrock, Claudia; Gore, Martin E; Eisen, Tim; Bruno, Ludovica

2010-04-01

As alpha-melanocyte-stimulating hormone (alpha-MSH) is released by immunocompetent cells and has potent immunosuppressive properties, it was determined whether human dendritic cells (DCs) express the receptor for this hormone. Reverse transcription-polymerase chain reaction detected messenger RNA specific for all of the known melanocortin receptors in DCs. Mixed lymphocyte reactions also revealed that treatment with [Nle(4), DPhe(7)]-alpha-MSH (NDP-MSH), a potent alpha-MSH analogue, significantly reduced the ability of DCs to stimulate allogeneic T cells. The expression of various cell surface adhesion, maturation and costimulatory molecules on DCs was also investigated. Although treatment with NDP-MSH did not alter the expression of CD83 and major histocompatibility complex class I and II, the surface expression of CD86 (B7.2), intercellular adhesion molecule (ICAM-1/CD54) and CD1a was reduced. In summary, our data indicate that NDP-MSH inhibits the functional activity of DCs, possibly by down-regulating antigen-presenting and adhesion molecules and that these events may be mediated via the extracellular signal-regulated kinase 1 and 2 pathway.

Eicosapentaenoic acid ameliorates non-alcoholic steatohepatitis in a novel mouse model using melanocortin 4 receptor-deficient mice.

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Konuma, Kuniha; Itoh, Michiko; Suganami, Takayoshi; Kanai, Sayaka; Nakagawa, Nobutaka; Sakai, Takeru; Kawano, Hiroyuki; Hara, Mitsuko; Kojima, Soichi; Izumi, Yuichi; Ogawa, Yoshihiro

2015-01-01

Many attempts have been made to find novel therapeutic strategies for non-alcoholic steatohepatitis (NASH), while their clinical efficacy is unclear. We have recently reported a novel rodent model of NASH using melanocortin 4 receptor-deficient (MC4R-KO) mice, which exhibit the sequence of events that comprise hepatic steatosis, liver fibrosis, and hepatocellular carcinoma with obesity-related phenotypes. In the liver of MC4R-KO mice, there is a unique histological feature termed hepatic crown-like structures (hCLS), where macrophages interact with dead hepatocytes and fibrogenic cells, thereby accelerating inflammation and fibrosis. In this study, we employed MC4R-KO mice to examine the effect of highly purified eicosapentaenoic acid (EPA), a clinically available n-3 polyunsaturated fatty acid, on the development of NASH. EPA treatment markedly prevented the development of hepatocyte injury, hCLS formation and liver fibrosis along with lipid accumulation. EPA treatment was also effective even after MC4R-KO mice developed NASH. Intriguingly, improvement of liver fibrosis was accompanied by the reduction of hCLS formation and plasma kallikrein-mediated transforming growth factor-β activation. Moreover, EPA treatment increased the otherwise reduced serum concentrations of adiponectin, an adipocytokine with anti-inflammatory and anti-fibrotic properties. Collectively, EPA treatment effectively prevents the development and progression of NASH in MC4R-KO mice along with amelioration of hepatic steatosis. This study unravels a novel anti-fibrotic mechanism of EPA, thereby suggesting a clinical implication for the treatment of NASH.

Eicosapentaenoic acid ameliorates non-alcoholic steatohepatitis in a novel mouse model using melanocortin 4 receptor-deficient mice.

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Kuniha Konuma

Full Text Available Many attempts have been made to find novel therapeutic strategies for non-alcoholic steatohepatitis (NASH, while their clinical efficacy is unclear. We have recently reported a novel rodent model of NASH using melanocortin 4 receptor-deficient (MC4R-KO mice, which exhibit the sequence of events that comprise hepatic steatosis, liver fibrosis, and hepatocellular carcinoma with obesity-related phenotypes. In the liver of MC4R-KO mice, there is a unique histological feature termed hepatic crown-like structures (hCLS, where macrophages interact with dead hepatocytes and fibrogenic cells, thereby accelerating inflammation and fibrosis. In this study, we employed MC4R-KO mice to examine the effect of highly purified eicosapentaenoic acid (EPA, a clinically available n-3 polyunsaturated fatty acid, on the development of NASH. EPA treatment markedly prevented the development of hepatocyte injury, hCLS formation and liver fibrosis along with lipid accumulation. EPA treatment was also effective even after MC4R-KO mice developed NASH. Intriguingly, improvement of liver fibrosis was accompanied by the reduction of hCLS formation and plasma kallikrein-mediated transforming growth factor-β activation. Moreover, EPA treatment increased the otherwise reduced serum concentrations of adiponectin, an adipocytokine with anti-inflammatory and anti-fibrotic properties. Collectively, EPA treatment effectively prevents the development and progression of NASH in MC4R-KO mice along with amelioration of hepatic steatosis. This study unravels a novel anti-fibrotic mechanism of EPA, thereby suggesting a clinical implication for the treatment of NASH.

Polymorphic variants of neurotransmitter receptor genes may affect sexual function in aging males: data from the HALS study.

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Jóźków, Paweł; Słowińska-Lisowska, Małgorzata; Łaczmański, Łukasz; Mędraś, Marek

2013-01-01

Human behavior is influenced by a number of brain neurotransmitters. Central dopamine, serotonin and melanocortin systems have special importance for male sexual function. We searched for associations between male aging symptoms and polymorphic sites of serotonin (5-HTR1B), melanocortin (MC4R) and dopamine (DRD2, DRD4) receptors. In a population-based sample, genotyping of 5-HTR1B (polymorphism: G861C), MC4R (polymorphisms: C-2745T, Val103Ile), DRD2 (polymorphism: C313T) and DRD4 (polymorphism: 48-bp VNTR) was performed in 387 healthy men. The Aging Males' Symptoms (AMS) scale was used to evaluate specific ailments of aging men. We analyzed answers to questions from the AMS scale. Five points of the questionnaire addressed sexual symptoms of the aging male: feeling of passing one's peak, decrease in beard growth, decrease in ability/frequency to perform sexually, decrease in the number of morning erections, and decrease in sexual desire/libido (lacking pleasure in sex, lacking desire for sexual intercourse). Relations between reported symptoms and variants of the polymorphic sites of the studied genes were assessed. After adjusting for confounding factors (education, arterial hypertension, physical activity, weight, waist circumference) an association between the sexual dimension of AMS and genetic variants of 5-HTR1B G861C (p = 0.04) was observed. Variability of neurotransmitter receptor genes may be associated with sexual symptoms of aging in men. Copyright © 2013 S. Karger AG, Basel.

Association of estradiol on expression of melanocortin receptors and their accessory proteins in the liver of chicken (Gallus gallus).

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Ren, Junxiao; Li, Yanmin; Xu, Naiyi; Li, Hong; Li, Cuicui; Han, Ruili; Wang, Yanbin; Li, Zhuanjian; Kang, Xiangtao; Liu, Xiaojun; Tian, Yadong

2017-01-01

The melanocortin receptor accessory proteins (MRAP and MRAP2) are small single-pass transmembrane proteins that regulate the biological functions of the melanocortin receptor (MCR) family. MCRs comprise five receptors (MC1R-MC5R) with diverse physiological roles in mammals. Five MCR members and two MRAPs were also predicted in the chicken (Gallus gallus) genome. However, little is known about their expression, regulation and biological functions. In this study, we cloned the MRAP and MRAP2 genes. Sequencing analysis revealed that the functional domains of MRAP and MRAP2 were conserved among species, suggesting that the physiological roles of chicken MRAP and MRAP2 could be similar to their mammalian counterparts. Tissue expression analysis demonstrated that MRAP was expressed in the adrenal gland, liver, spleen, glandular stomach and lungs, while MRAP2 is predominantly expressed in the adrenal gland. All five MCRs were present in the adrenal gland, but showed different expression patterns in other tissues. The MC5R was the only MCR member that was expressed in the chicken liver. The expression levels of MRAP in chicken liver were significantly increased at sexual maturity stage, and were significantly up-regulated (Pchickens and chicken primary hepatocytes were treated with 17β-estradiol in vivo and in vitro, respectively; however, expression levels of PPARγ were down-regulated, and no effect on MC5R was observed. Our results suggested that estrogen could stimulate the expression of MRAP in the liver of chicken through inhibiting the expression of transcription regulation factor PPARγ, and MRAP might play its biological role in a different way rather than forming an MRAP/MC2R complex in chicken liver during the egg-laying period. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of tetrapeptides from a mixture based positional scanning library that can restore nM full agonist function of the L106P, I69T, I102S, A219V, C271Y, and C271R human melanocortin-4 polymorphic receptors (hMC4Rs).

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Haslach, Erica M; Huang, Huisuo; Dirain, Marvin; Debevec, Ginamarie; Geer, Phaedra; Santos, Radleigh G; Giulianotti, Marc A; Pinilla, Clemencia; Appel, Jon R; Doering, Skye R; Walters, Michael A; Houghten, Richard A; Haskell-Luevano, Carrie

2014-06-12

Human obesity has been linked to genetic factors and single nucleotide polymorphisms (SNPs). Melanocortin-4 receptor (MC4R) SNPs have been associated with up to 6% frequency in morbidly obese children and adults. A potential therapy for individuals possessing such genetic modifications is the identification of molecules that can restore proper receptor signaling and function. These compounds could serve as personalized medications improving quality of life issues as well as alleviating diseases symptoms associated with obesity including type 2 diabetes. Several hMC4 SNP receptors have been pharmacologically characterized in vitro to have a decreased, or a lack of response, to endogenous agonists such as α-, β-, and γ2-melanocyte stimulating hormones (MSH) and adrenocorticotropin hormone (ACTH). Herein we report the use of a mixture based positional scanning combinatorial tetrapeptide library to discover molecules with nM full agonist potency and efficacy to the L106P, I69T, I102S, A219V, C271Y, and C271R hMC4Rs. The most potent compounds at all these hMC4R SNPs include Ac-His-(pI)DPhe-Tic-(pNO2)DPhe-NH2, Ac-His-(pCl)DPhe-Tic-(pNO2)DPhe-NH2, Ac-His-(pCl)DPhe-Arg-(pI)Phe-NH2, and Ac-Arg-(pCl)DPhe-Tic-(pNO2)DPhe-NH2, revealing new ligand pharmacophore models for melanocortin receptor drug design strategies.

The effect of interaction between Melanocortin-4 receptor polymorphism and dietary factors on the risk of metabolic syndrome.

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Koochakpoor, Gelareh; Daneshpour, Maryam S; Mirmiran, Parvin; Hosseini, Seyed Ahmad; Hosseini-Esfahani, Firoozeh; Sedaghatikhayat, Bahareh; Azizi, Fereidoun

2016-01-01

Controversial data is available on the effect of the Melanocortin-4 receptor (MC4R) gene variation on metabolic syndrome (MetS) and ineffectiveness of diet in managing MetS. Effects of the interaction between MC4R polymorphism and dietary factors on MetS were investigated in this study. Subjects of this nested case-control study were selected from among participants of Tehran Lipid and Glucose Study. Each case (n = 815) was pair matched randomly with a control by age (±5 years) and sex from among those who had not developed ≥1 MetS components at the time that the corresponding case developed MetS. Dietary patterns were determined using factor analysis on 25 foods groups using a valid and reliable, 168-item semi-quantitative food frequency questionnaire (FFQ). MC4R rs12970134 were genotyped by Tetra-Primer ARMS-polymerase chain reaction analysis. Adjusted conditional logistic regression was used to estimate the interactions of SNP with quartiles of dietary factors in relation to MetS. MetS was defined by the modified National Cholesterol Education Program/Adult Treatment panel III. Two dietary patterns were extracted. The healthy dietary pattern was loaded heavily on vegetables, legumes, low fat dairy, whole grains, liquid oils and fruits; the western dietary pattern consisted of a high intake of soft drinks, fast foods, sweets, solid oils, red meats, salty snacks, refined grains, high fat dairy, tea and coffee, eggs and poultry. Among A allele carriers, being in the highest quartiles of western dietary pattern score and saturated fatty acid intake had an increased risk of MetS, compared to those in the lowest quartile (P trend = 0.007). Saturated fatty acid intake could modulate the association of A allele carriers of MC4R with MetS (P interaction = 0.03). A significant interaction was observed between rs12970134 with total fat and iron intake on the risk of abdominal obesity (P interaction < 0.05). Our findings suggest an interaction between rs

Comparative in Vivo Investigation of Intrathecal and Intracerebroventricular Administration with Melanocortin Ligands MTII and AGRP into Mice.

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Adank, Danielle N; Lunzer, Mary M; Lensing, Cody J; Wilber, Stacey L; Gancarz, Amy M; Haskell-Luevano, Carrie

2018-02-21

Central administration of melanocortin ligands has been used as a critical technique to study energy homeostasis. While intracerebroventricular (ICV) injection is the most commonly used method during these investigations, intrathecal (IT) injection can be equally efficacious for the central delivery of ligands. Importantly, intrathecal administration can optimize exploration of melanocortin receptors in the spinal cord. Herein, we investigate comparative IT and ICV administration of two melanocortin ligands, the synthetic MTII (Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH 2 ) MC4R agonist and agouti-related peptide [AGRP(87-132)] MC4R inverse agonist/antagonist, on the same batch of age-matched mice in TSE metabolic cages undergoing a nocturnal satiated paradigm. To our knowledge, this is the first study to test how central administration of these ligands directly to the spinal cord affects energy homeostasis. Results showed, as expected, that MTII IT administration caused a decrease in food and water intake and an overall negative energy balance without affecting activity. As anticipated, IT administration of AGRP caused weight gain, increase of food/water intake, and increase respiratory exchange ratio (RER). Unexpectantly, the prolonged activity of AGRP was notably shorter (2 days) compared to mice given ICV injections of the same concentrations in previous studies (7 days or more).1-4 It appears that IT administration results in a more sensitive response that may be a good approach for testing synthetic compound potency values ranging in nanomolar to high micromolar in vitro EC 50 values. Indeed, our investigation reveals that the spine influences a different melanocortin response compared to the brain for the AGRP ligand. This study indicates that IT administration can be a useful technique for future metabolic studies using melanocortin ligands and highlights the importance of exploring the role of melanocortin receptors in the spinal cord.

A Novel Melanocortin-4 Receptor Mutation MC4R-P272L Associated with Severe Obesity Has Increased Propensity To Be Ubiquitinated in the ER in the Face of Correct Folding

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Granell, Susana; Serra-Juhé, Clara; Martos-Moreno, Gabriel Á.; Díaz, Francisca; Pérez-Jurado, Luis A.; Baldini, Giulia; Argente, Jesús

2012-01-01

Heterozygous mutations in the melanocortin-4 receptor (MC4R) gene represent the most frequent cause of monogenic obesity in humans. MC4R mutation analysis in a cohort of 77 children with morbid obesity identified previously unreported heterozygous mutations (P272L, N74I) in two patients inherited from their obese mothers. A rare polymorphism (I251L, allelic frequency: 1/100) reported to protect against obesity was found in another obese patient. When expressed in neuronal cells, the cell surface abundance of wild-type MC4R and of the N74I and I251L variants and the cAMP generated by these receptors in response to exposure to the agonist, α-MSH, were not different. Conversely, MC4R P272L was retained in the endoplasmic reticulum and had reduced cell surface expression and signaling (by ≈3-fold). The chemical chaperone PBA, which promotes protein folding of wild-type MC4R, had minimal effects on the distribution and signaling of the P272L variant. In contrast, incubation with UBE-41, a specific inhibitor of ubiquitin activating enzyme E1, inhibited ubiquitination of MC4R P272L and increased its cell surface expression and signaling to similar levels as wild-type MC4R. UBE41 had much less profound effects on MC4R I316S, another obesity-linked MC4R variant trapped in the ER. These data suggest that P272L is retained in the ER by a propensity to be ubiquitinated in the face of correct folding, which is only minimally shared by MC4R I316S. Thus, studies that combine clinical screening of obese patients and investigation of the functional defects of the obesity-linked MC4R variants can identify specific ways to correct these defects and are the first steps towards personalized medicine. PMID:23251400

Structure-activity relationships of the unique and potent agouti-related protein (AGRP)-melanocortin chimeric Tyr-c[beta-Asp-His-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH2 peptide template.

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Wilczynski, Andrzej; Wilson, Krista R; Scott, Joseph W; Edison, Arthur S; Haskell-Luevano, Carrie

2005-04-21

The melanocortin receptor system consists of endogenous agonists, antagonists, G-protein coupled receptors, and auxiliary proteins that are involved in the regulation of complex physiological functions such as energy and weight homeostasis, feeding behavior, inflammation, sexual function, pigmentation, and exocrine gland function. Herein, we report the structure-activity relationship (SAR) of a new chimeric hAGRP-melanocortin agonist peptide template Tyr-c[beta-Asp-His-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) that was characterized using amino acids previously reported in other melanocortin agonist templates. Twenty peptides were examined in this study, and six peptides were selected for (1)H NMR and computer-assisted molecular modeling structural analysis. The most notable results include the identification that modification of the chimeric template at the His position with Pro and Phe resulted in ligands that were nM mouse melanocortin-3 receptor (mMC3R) antagonists and nM mouse melanocortin-4 receptor (mMC4R) agonists. The peptides Tyr-c[beta-Asp-His-DPhe-Ala-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) and Tyr-c[beta-Asp-His-DNal(1')-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) resulted in 730- and 560-fold, respectively, mMC4R versus mMC3R selective agonists that also possessed nM agonist potency at the mMC1R and mMC5R. Structural studies identified a reverse turn occurring in the His-DPhe-Arg-Trp domain, with subtle differences observed that may account for the differences in melanocortin receptor pharmacology. Specifically, a gamma-turn secondary structure involving the DPhe(4) in the central position of the Tyr-c[beta-Asp-Phe-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) peptide may differentiate the mixed mMC3R antagonist and mMC4R agonist pharmacology.

Discovery of melanocortin ligands via a double simultaneous substitution strategy based on the Ac-His-DPhe-Arg-Trp-NH2 template.

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Todorovic, Aleksandar; Lensing, Cody J; Holder, Jerry Ryan; Scott, Joseph W; Sorensen, Nicholas B; Haskell-Luevano, Carrie

2018-05-21

The melanocortin system regulates an array of diverse physiological functions including pigmentation, feeding behavior, energy homeostasis, cardiovascular regulation, sexual function, and steroidogenesis. Endogenous melanocortin agonist ligands all possess the minimal messaging tetrapeptide sequence His-Phe-Arg-Trp. Based on this endogenous sequence, the Ac-His1-DPhe2-Arg3-Trp4-NH 2 tetrapeptide has previously been shown to be a useful scaffold when utilizing traditional positional scanning approaches to modify activity at the various melanocortin receptors (MC1-5R). The study reported herein was undertaken to evaluate a double simultaneous substitution strategy as an approach to further diversify the Ac-His1-DPhe2-Arg3-Trp4-NH 2 tetrapeptide with concurrent introduction of natural and unnatural amino acids at positions 1, 2, or 4 as well as an octanoyl residue at the N-terminus. The designed library includes the following combinations: (A) double simultaneous substitution at capping group position (Ac) together with position 1, 2, or 4, (B) double simultaneous substitution at position 1 and 2, (C) double simultaneous substitution at position 1 and 4, and (D) double simultaneous substitution at position 2 and 4. Several lead ligands with unique pharmacologies were discovered in the current study including antagonists targeting the neuronal mMC3R with minimal agonist activity and ligands with selective profiles for the various melanocortin subtypes. The results suggest that the double simultaneous substitution strategy is a suitable approach in altering melanocortin receptor potency, selectivity, or converting agonists into antagonists and vice versa.

Melanocortin-1 receptor activation is neuroprotective in mouse models of neuroinflammatory disease.

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Mykicki, Nadine; Herrmann, Alexander M; Schwab, Nicholas; Deenen, René; Sparwasser, Tim; Limmer, Andreas; Wachsmuth, Lydia; Klotz, Luisa; Köhrer, Karl; Faber, Cornelius; Wiendl, Heinz; Luger, Thomas A; Meuth, Sven G; Loser, Karin

2016-10-26

In inflammation-associated progressive neuroinflammatory disorders, such as multiple sclerosis (MS), inflammatory infiltrates containing T helper 1 (T H 1) and T H 17 cells cause demyelination and neuronal degeneration. Regulatory T cells (T reg ) control the activation and infiltration of autoreactive T cells into the central nervous system (CNS). In MS and experimental autoimmune encephalomyelitis (EAE) in mice, T reg function is impaired. We show that a recently approved drug, Nle 4 -d-Phe 7 -α-melanocyte-stimulating hormone (NDP-MSH), induced functional T reg , resulting in amelioration of EAE progression in mice. NDP-MSH also prevented immune cell infiltration into the CNS by restoring the integrity of the blood-brain barrier. NDP-MSH exerted long-lasting neuroprotective effects in mice with EAE and prevented excitotoxic death and reestablished action potential firing in mouse and human neurons in vitro. Neuroprotection by NDP-MSH was mediated via signaling through the melanocortin-1 and orphan nuclear 4 receptors in mouse and human neurons. NDP-MSH may be of benefit in treating neuroinflammatory diseases such as relapsing-remitting MS and related disorders. Copyright © 2016, American Association for the Advancement of Science.

Design, synthesis, structural and functional characterization of novel melanocortin agonists based on the cyclotide kalata B1

DEFF Research Database (Denmark)

Eliasen, Rasmus; Daly, Norelle L.; Wulff, Birgitte S.

2012-01-01

Obesity is an increasingly important global health problem that lacks current treatment options. The melanocortin receptor 4 (MC4R) is a target for obesity therapies because its activation triggers appetite suppression and increases energy expenditure. Cyclotides have been suggested as scaffolds ...

Influence of silencing the MC4R gene by lentivirusmediated RNA ...

African Journals Online (AJOL)

Melanocortin receptor 4 (MC4R) is a key element in the mechanisms used to regulate both aspects of keeping the balance between energy uptake and energy expenditure. MC4R was knocked down by lentivirus-mediated shRNA expressing plasmids, which were controlled by the U6 promoter in bovine fibroblast cells, and ...

Regulation of lean mass, bone mass, and exercise tolerance by the central melanocortin system.

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Theodore P Braun

Full Text Available Signaling via the type 4-melanocortin receptor (MC4R is an important determinant of body weight in mice and humans, where loss of function mutations lead to significant obesity. Humans with mutations in the MC4R experience an increase in lean mass. However, the simultaneous accrual of fat mass in such individuals may contribute to this effect via mechanical loading. We therefore examined the relationship of fat mass and lean mass in mice lacking the type-4 melanocortin receptor (MC4RKO. We demonstrate that MC4RKO mice display increased lean body mass. Further, this is not dependent on changes in adipose mass, as MC4RKO mice possess more lean body mass than diet-induced obese (DIO wild type mice with equivalent fat mass. To examine potential sources of the increased lean mass in MC4RKO mice, bone mass and strength were examined in MC4RKO mice. Both parameters increase with age in MC4RKO mice, which likely contributes to increases in lean body mass. We functionally characterized the increased lean mass in MC4RKO mice by examining their capacity for treadmill running. MC4R deficiency results in a decrease in exercise performance. No changes in the ratio of oxidative to glycolytic fibers were seen, however MC4RKO mice demonstrate a significantly reduced heart rate, which may underlie their impaired exercise performance. The reduced exercise capacity we report in the MC4RKO mouse has potential clinical ramifications, as efforts to control body weight in humans with melanocortin deficiency may be ineffective due to poor tolerance for physical activity.

Sequence variation in the melanocortin-1 receptor (MC1R pigmentation gene and its role in the cryptic coloration of two South American sand lizards

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Josmael Corso

2012-01-01

Full Text Available In reptiles, dorsal body darkness often varies with substrate color or temperature environment, and is generally presumed to be an adaptation for crypsis or thermoregulation. However, the genetic basis of pigmentation is poorly known in this group. In this study we analyzed the coding region of the melanocortin-1-receptor (MC1R gene, and therefore its role underlying the dorsal color variation in two sympatric species of sand lizards (Liolaemus that inhabit the southeastern coast of South America: L. occipitalis and L. arambarensis. The first is light-colored and occupies aeolic pale sand dunes, while the second is brownish and lives in a darker sandy habitat. We sequenced 630 base pairs of MC1R in both species. In total, 12 nucleotide polymorphisms were observed, and four amino acid replacement sites, but none of them could be associated with a color pattern. Comparative analysis indicated that these taxa are monomorphic for amino acid sites that were previously identified as functionally important in other reptiles. Thus, our results indicate that MC1R is not involved in the pigmentation pattern observed in Liolaemus lizards. Therefore, structural differences in other genes, such as ASIP, or variation in regulatory regions of MC1R may be responsible for this variation. Alternatively, the phenotypic differences observed might be a consequence of non-genetic factors, such as thermoregulatory mechanisms.

Melanocortin-4 receptor polymorphism rs17782313: association with obesity and eating in the absence of hunger in Chilean children.

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Ho-Urriola, Judith; Guzmán-Guzmán, Iris P; Smalley, Susan V; González, Andrea; Weisstaub, Gerardo; Domínguez-Vásquez, Patricia; Valladares, Macarena; Amador, Paola; Hodgson, M Isabel; Obregón, Ana M; Santos, José L

2014-02-01

The aim of this study was to assess the association between melanocortin-4 receptor (MC4R) rs17782313 alleles with obesity and eating behavior scores in Chilean children. A case-control study was conducted with 139 normal-weight and 238 obese children (ages 6-12 y). MC4R rs17782313 genotypes were determined by quantitative-polymerase chain reaction allelic-discrimination assays. Eating behavior scores were evaluated in a subset of participants using the Chilean version of the Child Eating Behavior Questionnaire (CEBQ). Additionally, five normal-weight C-allele carriers of rs17782313 were matched by sex, age, and body mass index (BMI) to five TT homozygous children to carry out the Eating in the Absence of Hunger (EAH) test. The frequency of the C-allele of MC4R rs17782313 was higher in the obese group than in the control group, without achieving statistical significance (odds ratio, 1.4; 95% confidence interval, 0.8-2.4; P = 0.16). CEBQ scores of "enjoyment of food" were higher (P = 0.04) and "satiety responsiveness" were lower (P = 0.02) in children with CC genotype than in those with TT genotype matched by sex, age, and BMI. In the EAH test, all five non-obese carriers of the C-allele (three CC and two CT) showed increased sweet snack consumption compared with five matched (by sex-age-BMI) non-carriers after a preload meal, without achieving statistical significance (P = 0.06). MC4R polymorphism rs17782313 may contribute to childhood obesity, affecting enjoyment of food, satiety responsiveness, and possibly eating in the absence of hunger. Copyright © 2014 Elsevier Inc. All rights reserved.

Fish pigmentation and the melanocortin system.

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Cal, Laura; Suarez-Bregua, Paula; Cerdá-Reverter, José Miguel; Braasch, Ingo; Rotllant, Josep

2017-09-01

The melanocortin system is a complex neuroendocrine signaling mechanism involved in numerous physiological processes in vertebrates, including pigmentation, steroidogenesis and metabolic control. This review focuses at one of its most fascinating function in fish, its regulatory role in the control of pigmentation, in which the melanocortin 1 receptor (Mc1r), its agonist α-melanocyte stimulating hormone (α-Msh), and the endogenous antagonist agouti signaling protein (Asip1) are the main players. Functional control of Mc1r, which is highly expressed in fish skin and whose activation stimulates melanin production and melanosome dispersion in fish melanophores, is considered a key mechanism for vertebrate pigment phenotypes. The α-Msh peptide, the most documented Mc1r agonist involved in pigmentation, is produced in the pituitary gland, activating melanin synthesis by binding to Mc1r in fish melanophores. Finally, Asip1 is the putative factor for establishing the evolutionarily conserved dorso-ventral pigment pattern found across vertebrates. However, we are just starting to understand how other melanocortin system components are acting in this complex regulatory network. Copyright © 2017 Elsevier Inc. All rights reserved.

The Role of the Melanocortin System in Metabolic Disease: New Developments and Advances.

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Hill, Jennifer W; Faulkner, Latrice D

2017-01-01

Obesity is increasing in prevalence across all sectors of society, and with it a constellation of associated ailments including hypertension, type 2 diabetes, and eating disorders. The melanocortin system is a critical neural system underlying the control of body weight and other functions. Deficits in the melanocortin system may promote or exacerbate the comorbidities of obesity. This system has therefore generated great interest as a potential target for treatment of obesity. However, drugs targeting melanocortin receptors are plagued by problematic side effects, including undesirable increases in sympathetic nervous system activity, heart rate, and blood pressure. Circumnavigating this roadblock will require a clearer picture of the precise neural circuits that mediate the functions of melanocortins. Recent, novel experimental approaches have significantly advanced our understanding of these pathways. We here review the latest advances in our understanding of the role of melanocortins in food intake, reward pathways, blood pressure, glucose control, and energy expenditure. The evidence suggests that downstream melanocortin-responsive circuits responsible for different physiological actions do diverge. Ultimately, a more complete understanding of melanocortin pathways and their myriad roles should allow treatments tailored to the mix of metabolic disorders in the individual patient. © 2016 The Author(s) Published by S. Karger AG, Basel.

Melanocortin 1 receptor (MC1R) gene sequence variation and melanism in the gray (Sciurus carolinensis), fox (Sciurus niger), and red (Sciurus vulgaris) squirrel.

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McRobie, Helen R; King, Linda M; Fanutti, Cristina; Coussons, Peter J; Moncrief, Nancy D; Thomas, Alison P M

2014-01-01

Sequence variations in the melanocortin 1 receptor (MC1R) gene are associated with melanism in many different species of mammals, birds, and reptiles. The gray squirrel (Sciurus carolinensis), found in the British Isles, was introduced from North America in the late 19th century. Melanism in the British gray squirrel is associated with a 24-bp deletion in the MC1R. To investigate the origin of this mutation, we sequenced the MC1R of 95 individuals including 44 melanic gray squirrels from both the British Isles and North America. Melanic gray squirrels of both populations had the same 24-bp deletion associated with melanism. Given the significant deletion associated with melanism in the gray squirrel, we sequenced the MC1R of both wild-type and melanic fox squirrels (Sciurus niger) (9 individuals) and red squirrels (Sciurus vulgaris) (39 individuals). Unlike the gray squirrel, no association between sequence variation in the MC1R and melanism was found in these 2 species. We conclude that the melanic gray squirrel found in the British Isles originated from one or more introductions of melanic gray squirrels from North America. We also conclude that variations in the MC1R are not associated with melanism in the fox and red squirrels.

Significance of the Melanocortin 1 and Endothelin B Receptors in Melanocyte Homeostasis and Prevention of Sun-Induced Genotoxicity

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Zalfa A. Abdel-Malek

2016-08-01

Full Text Available The membrane bound melanocortin 1 receptor (MC1R, and the endothelin B receptor (ENDBR are two G-protein coupled receptors that play important roles in constitutive regulation of melanocytes and their response to ultraviolet radiation (UVR, the main etiological factor for melanoma. The human MC1R is a Gs protein-coupled receptor, which is activated by its agonists α-melanocyte stimulating hormone (α-melanocortin; α-MSH and adrenocorticotropic hormone (ACTH. The ENDBR is a Gq coupled-receptor, which is activated by Endothelin (ET-3 during embryonic development, and ET-1 postnatally. Pigmentation and the DNA repair capacity are two major factors that determine the risk for melanoma. Activation of the MC1R by its agonists stimulates the synthesis of eumelanin, the dark brown photoprotective pigment. In vitro studies showed that α-MSH and ET-1 interact synergistically in the presence of basic fibroblast growth factor (bFGF to stimulate human melanocyte proliferation and melanogenesis, and to inhibit UVR-induced apoptosis. An important function of the MC1R is reduction of oxidative stress and activation of DNA repair pathways. The human MC1R is highly polymorphic, and MC1R variants, particularly those that cause loss of function of the expressed receptor, are associated with increased melanoma risk independently of pigmentation. These variants compromise the DNA repair and antioxidant capacities of human melanocytes. Recently, activation of ENDBR by ET-1 was reported to reduce the induction and enhance the repair of UVR-induced DNA photoproducts. We conclude that α-MSH and ET-1 and their cognate receptors MC1R and ENDBR reduce the risk for melanoma by maintaining genomic stability of melanocytes via modulating the DNA damage response to solar UVR. Elucidating the response of melanocytes to UVR should improve our understanding of the process of melanomagenesis, and lead to effective melanoma chemoprevention, as well as therapeutic strategies.

Color differences among feral pigeons (Columba livia) are not attributable to sequence variation in the coding region of the melanocortin-1 receptor gene (MC1R)

Science.gov (United States)

2013-01-01

Background Genetic variation at the melanocortin-1 receptor (MC1R) gene is correlated with melanin color variation in many birds. Feral pigeons (Columba livia) show two major melanin-based colorations: a red coloration due to pheomelanic pigment and a black coloration due to eumelanic pigment. Furthermore, within each color type, feral pigeons display continuous variation in the amount of melanin pigment present in the feathers, with individuals varying from pure white to a full dark melanic color. Coloration is highly heritable and it has been suggested that it is under natural or sexual selection, or both. Our objective was to investigate whether MC1R allelic variants are associated with plumage color in feral pigeons. Findings We sequenced 888 bp of the coding sequence of MC1R among pigeons varying both in the type, eumelanin or pheomelanin, and the amount of melanin in their feathers. We detected 10 non-synonymous substitutions and 2 synonymous substitution but none of them were associated with a plumage type. It remains possible that non-synonymous substitutions that influence coloration are present in the short MC1R fragment that we did not sequence but this seems unlikely because we analyzed the entire functionally important region of the gene. Conclusions Our results show that color differences among feral pigeons are probably not attributable to amino acid variation at the MC1R locus. Therefore, variation in regulatory regions of MC1R or variation in other genes may be responsible for the color polymorphism of feral pigeons. PMID:23915680

Polymorphisms of the dopamine D4 receptor gene (DRD4 VNTR) and cannabinoid CB1 receptor gene (CNR1) are not strongly related to cue-reactivity after alcohol exposure

NARCIS (Netherlands)

Wildenberg, E. van den; Janssen, R.G.J.H.; Hutchison, K.E.; Breukelen, G.J.P. van; Wiers, R.W.H.J.

2007-01-01

Polymorphisms in the D4 dopamine receptor gene (DRD4) and the CB1 cannabinoid receptor gene (CNR1) have been associated with a differential response to alcohol after consumption. The goal of the present study was to investigate whether heavy drinkers with these polymorphisms would respond with

Modified melanocortin tetrapeptide Ac-His-dPhe-Arg-Trp-NH at the arginine side chain with ureas and thioureas.

Science.gov (United States)

Joseph, C G; Sorensen, N B; Wood, M S; Xiang, Z; Moore, M C; Haskell-Luevano, C

2005-11-01

The Ac-His-dPhe-Arg-Trp-NH2 tetrapeptide is a nonselective melanocortin agonist and replacement of Arg in the tetrapeptide with acidic, basic or neutral amino acids results in reduced potency at the melanocortin receptor (MCR) isoforms (MC1R and MC3-5R). To determine the importance of the positive charge and the guanidine moiety for melanocortin activity, a series of urea- and thiourea-substituted tetrapeptides were designed. Replacement of Arg with Lys or ornithine reduced agonist activity at the mouse mMC1 and mMC3-5 receptors, thus supporting the hypothesis that the guanidine moiety is important for receptor potency, particularly at the MC3-5 receptors. The Arg side chain-modified tetrapeptides examined in this study include substituted phenyl, naphthyl, and aliphatic urea and thiourea residues using a Lys side-chain template. These ligands elicit full-agonist pharmacology at the mouse MCRs examined in this study.

Developmental Programming of Obesity and Liver Metabolism by Maternal Perinatal Nutrition Involves the Melanocortin System

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Paul Cordero

2017-09-01

Full Text Available Maternal obesity predisposes offspring to metabolic dysfunction and Non-Alcoholic Fatty Liver Disease (NAFLD. Melanocortin-4 receptor (Mc4r-deficient mouse models exhibit obesity during adulthood. Here, we aim to determine the influence of the Mc4r gene on the liver of mice subjected to perinatal diet-induced obesity. Female mice heterozygous for Mc4r fed an obesogenic or a control diet for 5 weeks were mated with heterozygous males, with the same diet continued throughout pregnancy and lactation, generating four offspring groups: control wild type (C_wt, control knockout (C_KO, obese wild type (Ob_wt, and obese knockout (Ob_KO. At 21 days, offspring were genotyped, weaned onto a control diet, and sacrificed at 6 months old. Offspring phenotypic characteristics, plasma biochemical profile, liver histology, and hepatic gene expression were analyzed. Mc4r_ko offspring showed higher body, liver and adipose tissue weights respect to the wild type animals. Histological examination showed mild hepatic steatosis in offspring group C_KO. The expression of hepatic genes involved in regulating inflammation, fibrosis, and immune cell infiltration were upregulated by the absence of the Mc4r gene. These results demonstrate that maternal obesogenic feeding during the perinatal period programs offspring obesity development with involvement of the Mc4r system.

Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2 induces penile erection via brain and spinal melanocortin receptors.

Science.gov (United States)

Wessells, H; Hruby, V J; Hackett, J; Han, G; Balse-Srinivasan, P; Vanderah, T W

2003-01-01

Penile erection induced by alpha-melanocyte-stimulating hormone and melanocortin receptors (MC-R) in areas of the spinal cord and periphery has not been demonstrated. To elucidate sites of the proerectile action of melanocortin peptides, in awake male rats we administered the MC-R agonist Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH(2) (MT-II) i.c.v., intrathecal (i.th.) and i.v. and scored penile erection and yawning. Injection of the MC-R antagonist Ac-Nle-c[Asp-His-DNal(2')-Arg-Trp-Lys]-NH(2) (SHU-9119) i.c.v. or i.th. in combination with i.th. MT-II differentiated spinal from supraspinal effects. To exclude a site of action in the penis, we recorded intracavernous pressure responses to intracavernosal injection of MT-II in the anesthetized rat.I.c.v., i.th., and i.v. MT-II induced penile erections in a dose-dependent fashion. Yawning was observed with i.c.v. and i.v. MT-II, while spinal injection did not produce this behavior. Intrathecal delivery of MT-II to the lumbosacral spinal cord was more efficacious in inducing erections than i.c.v. or i.v. administration; SHU-9119 blocked the erectile responses to i.th. MT-II when injected i.th. but not i.c.v. Intracavernosal MT-II neither increased intracavernous pressure nor augmented neurostimulated erectile responses. We confirmed the central proerectile activity of MT-II and demonstrated that in addition to a site of action in the brain, the distal spinal cord contains melanocortin receptors that can initiate penile erection independent of higher centers. These results provide new insight into the central melanocortinergic pathways that mediate penile erection and may allow for more efficacious melanotropin-based therapy for erectile dysfunction.

Distinct pigmentary and melanocortin 1 receptor-dependent components of cutaneous defense against ultraviolet radiation.

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Craig S April

2007-01-01

Full Text Available Genetic variation at the melanocortin 1 receptor (MC1R is an important risk factor for developing ultraviolet (UV radiation-induced skin cancer, the most common form of cancer in humans. The underlying mechanisms by which the MC1R defends against UV-induced skin cancer are not known. We used neonatal mouse skin (which, like human skin, contains a mixture of melanocytes and keratinocytes to study how pigment cells and Mc1r genotype affect the genome-level response to UV radiation. Animals without viable melanocytes (Kit(W-v/Kit(W-v or animals lacking a functional Mc1r (Mc1r(e/Mc1r(e were exposed to sunburn-level doses of UVB radiation, and the patterns of large-scale gene expression in the basal epidermis were compared to each other and to nonmutant animals. Our analysis revealed discrete Kit- and Mc1r-dependent UVB transcriptional responses in the basal epidermis. The Kit-dependent UVB response was characterized largely by an enrichment of oxidative and endoplasmic reticulum stress genes, highlighting a distinctive role for pigmented melanocytes in mediating antioxidant defenses against genotoxic stresses within the basal epidermal environment. By contrast, the Mc1r-dependent UVB response contained an abundance of genes associated with regulating the cell cycle and oncogenesis. To test the clinical relevance of these observations, we analyzed publicly available data sets for primary melanoma and melanoma metastases and found that the set of genes specific for the Mc1r-dependent UVB response was able to differentiate between different clinical subtypes. Our analysis also revealed that the classes of genes induced by UVB differ from those repressed by UVB with regard to their biological functions, their overall number, and their size. The findings described here offer new insights into the transcriptional nature of the UV response in the skin and provide a molecular framework for the underlying mechanisms by which melanocytes and the Mc1r

The expression of the ACTH receptor

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L.L.K. Elias

2000-10-01

Full Text Available Adrenal glucocorticoid secretion is regulated by adrenocorticotropic hormone (ACTH acting through a specific cell membrane receptor (ACTH-R. The ACTH-R is a member of the G protein superfamily-coupled receptors and belongs to the subfamily of melanocortin receptors. The ACTH-R is mainly expressed in the adrenocortical cells showing a restricted tissue specificity, although ACTH is recognized by the other four melanocortin receptors. The cloning of the ACTH-R was followed by the study of this gene in human diseases such as familial glucocorticoid deficiency (FGD and adrenocortical tumors. FGD is a rare autosomal recessive disease characterized by glucocorticoid deficiency, elevated plasma ACTH levels and preserved renin/aldosterone secretion. This disorder has been ascribed to an impaired adrenal responsiveness to ACTH due to a defective ACTH-R, a defect in intracellular signal transduction or an abnormality in adrenal cortical development. Mutations of the ACTH-R have been described in patients with FGD in segregation with the disease. The functional characterization of these mutations has been prevented by difficulties in expressing human ACTH-R in cells that lack endogenous melanocortin receptor activity. To overcome these difficulties we used Y6 cells, a mutant variant of the Y1 cell line, which possesses a non-expressed ACTH-R gene allowing the functional study without any background activity. Our results demonstrated that the several mutations of the ACTH-R found in FGD result in an impaired cAMP response or loss of sensitivity to ACTH stimulation. An ACTH-binding study showed an impairment of ligand binding with loss of the high affinity site in most of the mutations studied.

Feeding induced by cannabinoids is mediated independently of the melanocortin system.

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Puspha Sinnayah

2008-05-01

Full Text Available Cannabinoids, the active components of marijuana, stimulate appetite, and cannabinoid receptor-1 (CB1-R antagonists suppress appetite and promote weight loss. Little is known about how CB1-R antagonists affect the central neurocircuitry, specifically the melanocortin system that regulates energy balance.Here, we show that peripherally administered CB1-R antagonist (AM251 or agonist equally suppressed or stimulated feeding respectively in A(y , which lack a functional melanocortin system, and wildtype mice, demonstrating that cannabinoid effects on feeding do not require melanocortin circuitry. CB1-R antagonist or agonist administered into the ventral tegmental area (VTA equally suppressed or stimulated feeding respectively, in both genotypes. In addition, peripheral and central cannabinoid administration similarly induced c-Fos activation in brain sites suggesting mediation via motivational dopaminergic circuitry. Amperometry-detected increases in evoked dopamine (DA release by the CB1-R antagonist in nucleus accumbens slices indicates that AM251 modulates DA release from VTA terminals.Our results demonstrate that the effects of cannabinoids on energy balance are independent of hypothalamic melanocortin circuitry and is primarily driven by the reward system.

A novel role for pigment genes in the stress response in rainbow trout (Oncorhynchus mykiss)

KAUST Repository

Khan, Uniza Wahid; Ø verli, Ø yvind; Hinkle, Patricia M.; Pasha, Farhan Ahmad; Johansen, Ida Beitnes; Berget, Ingunn; Silva, Patricia I. M.; Kittilsen, Silje; Hö glund, Erik; Omholt, Stig W.; Vå ge, Dag Inge

2016-01-01

pigmentation gene, melanocyte stimulating hormone receptor (MC1R), is strongly associated with distinct differences in steroidogenic melanocortin 2 receptor (MC2R) mRNA expression between high- (HR) and low-responsive (LR) rainbow trout (Oncorhynchus mykiss

The pituitary gland of the European eel reveals massive expression of genes involved in the melanocortin system.

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Eirill Ager-Wick

Full Text Available Hormones secreted from the pituitary gland regulate important processes such as development, growth and metabolism, reproduction, water balance, and body pigmentation. Synthesis and secretion of pituitary hormones are regulated by different factors from the hypothalamus, but also through feedback mechanisms from peripheral organs, and from the pituitary itself. In the European eel extensive attention has been directed towards understanding the different components of the brain-pituitary-gonad axis, but little is known about the regulation of upstream processes in the pituitary gland. In order to gain a broader mechanistic understanding of the eel pituitary gland, we have performed RNA-seq transcriptome profiling of the pituitary of prepubertal female silver eels. RNA-seq reads generated on the Illumina platform were mapped to the recently assembled European eel genome. The most abundant transcript in the eel pituitary codes for pro-opiomelanocortin, the precursor for hormones of the melanocortin system. Several genes putatively involved in downstream processing of pro-opiomelanocortin were manually annotated, and were found to be highly expressed, both by RNA-seq and by qPCR. The melanocortin system, which affects skin color, energy homeostasis and in other teleosts interacts with the reproductive system, has so far received limited attention in eels. However, since up to one third of the silver eel pituitary's mRNA pool encodes pro-opiomelanocortin, our results indicate that control of the melanocortin system is a major function of the eel pituitary.

[STUDYING THE ROLE OF BRAIN MELANOCORTIN RECEPTORS IN THE SUPPRESSING OF FOOD INTAKE UNDER ETHER STRESS IN MICE].

Science.gov (United States)

Bazhan, N M; Kulikova, E V; Makarova, E N; Yakovleva, T V; Kazantseva, A Yu

2015-12-01

Melanocortin (MC) system regulates food intake under the rest conditions. Stress inhibits food intake. It is not clear whether brain MC system is involved in stress-induced anorexia in mice. The aim of the work was to investigate the effect of pharmacological blockade and activation of brain MC receptors on food intake under stress. C57B1/6J male mice were subjected to ether stress (0.5 minute ether anesthesia) before the administration of saline solution or synthetic non-selective blocker (SHU9119) or agonist (Melanotan II) of MC receptors into the lateral brain ventricle. Food intake was pre-stimulated with 17 hours of fasting in all mice. Ether stress decreased food intake, increased the plasma corticosterone level and hypothalamic mRNA AgRP (natural MC receptor antagonist) level at 1 hour after the stress. Pharmacological blockade of the MC receptors weakened stress-induced anorexia and decreased mRNA AgRP level in the hypothalamus. Pharmacological stimulation of the MC receptors enhanced ether stress-induced anorexia and hypercortisolism. Thus, our data demonstrated that the central MC system was involved in the development of stress-induced anorexia in mice.

Annexin 1 and Melanocortin Peptide Therapy for Protection Against Ischaemic-Reperfusion Damage in the Heart

Directory of Open Access Journals (Sweden)

F.N.E. Gavins

2006-01-01

Full Text Available Cardiovascular disease is a major cause of mortality within the western world affecting 2.7 million British people. This review highlights the beneficial effects of naturally occurring hormones and their peptides, in myocardial ischaemic-injury (MI models, a disease pathology in which cytokines and neutrophils play a causal role. Here we discuss two distinct classes of endogenous peptides: the steroid inducible annexin 1 and the melanocortin peptides. Annexin 1 and the melanocortins counteract the most important part of the host inflammatory response, namely, the process of leukocyte extravasation, as well as release of proinflammatory mediators. Their biological effects are mediated via the seven transmembrane G-protein-coupled receptors, the fMLP receptor family (or FPR, and the melanocortin receptors, respectively. Pharmacological analysis has demonstrated that the first 24 amino acids of the N-terminus (termed Ac2-26 are the most active region. Both exogenous annexin 1 and its peptides demonstrate cardioprotectiveness and continuing work is required to understand this annexin 1/FPR relationship fully. The melanocortin peptides are derived from a precursor molecule called the POMC protein. These peptides display potent anti-inflammatory effects in human and animal models of disease. In MI, the MC3R has been demonstrated to play an important role in mediating the protective effects of these peptides. The potential anti-inflammatory role for endogenous peptides in cardiac disease is in its infancy. The inhibition of cell migration and release of cytokines and other soluble mediators appears to play an important role in affording protection in ischaemic injury and thus may lead to potential therapeutic targets.

Effects of pregnane glycosides on food intake depend on stimulation of the melanocortin pathway and BDNF in an animal model.

Science.gov (United States)

Komarnytsky, Slavko; Esposito, Debora; Rathinasabapathy, Thirumurugan; Poulev, Alexander; Raskin, Ilya

2013-02-27

Pregnane glycosides appear to modulate food intake by possibly affecting the hypothalamic feeding circuits; however, the mechanisms of the appetite-regulating effect of pregnane glycosides remain obscure. Here, we show that pregnane glycoside-enriched extracts from swamp milkweed Asclepias incarnata at 25-100 mg/kg daily attenuated food intake (up to 47.1 ± 8.5% less than controls) and body weight gain in rats (10% for males and 9% for females, respectively) by activating melanocortin signaling and inhibiting gastric emptying. The major milkweed pregnane glycoside, ikemagenin, exerted its appetite-regulating effect by decreasing levels of agouti-related protein (0.6-fold) but not NPY satiety peptides. Ikemagenin treatment also increased secretion of brain-derived neurotropic factor (BDNF) downstream of melanocortin receptors in the hypothalamus (1.4-fold) and in the C6 rat glioma cell culture in vitro (up to 6-fold). These results support the multimodal effects of pregnane glycosides on feeding regulation, which depends on the activity of the melanocortin signaling pathway and BDNF.

Pharmacological characterization of canine melancortin-4 receptor and its natural variant V213F

OpenAIRE

Yan, Jin; Tao, Ya-Xiong

2011-01-01

Dogs have become one of most important companion animals in the modern society. However, it is estimated that 20–40% of owned dogs are obese suggesting that obesity has become one of the most important canine health problem. In addition, obesity in dogs also leads to type II diabetes. Since the melanocortin-4 receptor (MC4R) has been demonstrated to be essential in maintaining energy homeostasis in several different species, including rodents and human, we initiated studies towards elucidatin...

Exocrine gland dysfunction in MC5-R-deficient mice: evidence for coordinated regulation of exocrine gland function by melanocortin peptides.

Science.gov (United States)

Chen, W; Kelly, M A; Opitz-Araya, X; Thomas, R E; Low, M J; Cone, R D

1997-12-12

The effects of pituitary-derived melanocortin peptides are primarily attributed to ACTH-mediated adrenocortical glucocorticoid production. Identification of a widely distributed receptor for ACTH/MSH peptides, the melanocortin-5 receptor (MC5-R), suggested non-steroidally mediated systemic effects of these peptides. Targeted disruption of the MC5-R produced mice with a severe defect in water repulsion and thermoregulation due to decreased production of sebaceous lipids. High levels of MC5-R was found in multiple exocrine tissues, including Harderian, preputial, lacrimal, and sebaceous glands, and was also shown to be required for production and stress-regulated synthesis of porphyrins by the Harderian gland and ACTH/MSH-regulated protein secretion by the lacrimal gland. These data show a requirement for the MC5-R in multiple exocrine glands for the production of numerous products, indicative of a coordinated system for regulation of exocrine gland function by melanocortin peptides.

Antagonism of the melanocortin system reduces cold and mechanical allodynia in mononeuropathic rats

NARCIS (Netherlands)

Gispen, W.H.; Vrinten, D.H.; Groen, G.J.; Adan, R.A.H.

2000-01-01

The presence of both pro-opiomelanocortin-derived peptides and melanocortin (MC) receptors in nociception-associated areas in the spinal cord suggests that, at the spinal level, the MC system might be involved in nociceptive transmission. In the present study, we demonstrate that a chronic

The role of leptin, melanocortin, and neurotrophin system genes on body weight in anorexia nervosa and bulimia nervosa.

Science.gov (United States)

Yilmaz, Zeynep; Kaplan, Allan S; Tiwari, Arun K; Levitan, Robert D; Piran, Sara; Bergen, Andrew W; Kaye, Walter H; Hakonarson, Hakon; Wang, Kai; Berrettini, Wade H; Brandt, Harry A; Bulik, Cynthia M; Crawford, Steven; Crow, Scott; Fichter, Manfred M; Halmi, Katherine A; Johnson, Craig L; Keel, Pamela K; Klump, Kelly L; Magistretti, Pierre; Mitchell, James E; Strober, Michael; Thornton, Laura M; Treasure, Janet; Woodside, D Blake; Knight, Joanne; Kennedy, James L

2014-08-01

Although low weight is a key factor contributing to the high mortality in anorexia nervosa (AN), it is unclear how AN patients sustain low weight compared with bulimia nervosa (BN) patients with similar psychopathology. Studies of genes involved in appetite and weight regulation in eating disorders have yielded variable findings, in part due to small sample size and clinical heterogeneity. This study: (1) assessed the role of leptin, melanocortin, and neurotrophin genetic variants in conferring risk for AN and BN; and (2) explored the involvement of these genes in body mass index (BMI) variations within AN and BN. Our sample consisted of 745 individuals with AN without a history of BN, 245 individuals with BN without a history of AN, and 321 controls. We genotyped 20 markers with known or putative function among genes selected from leptin, melanocortin, and neurotrophin systems. There were no significant differences in allele frequencies among individuals with AN, BN, and controls. AGRP rs13338499 polymorphism was associated with lowest illness-related BMI in those with AN (p = 0.0013), and NTRK2 rs1042571 was associated with highest BMI in those with BN (p = 0.0018). To our knowledge, this is the first study to address the issue of clinical heterogeneity in eating disorder genetic research and to explore the role of known or putatively functional markers in genes regulating appetite and weight in individuals with AN and BN. If replicated, our results may serve as an important first step toward gaining a better understanding of weight regulation in eating disorders. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification and characterization of a tandem repeat in exon III of the dopamine receptor D4 (DRD4) gene in cetaceans

DEFF Research Database (Denmark)

Mogensen, Line; Kinze, Carl Christian; Werge, Thomas

2006-01-01

A large number of mammalian species harbor a tandem repeat in exon III of the gene encoding dopamine receptor D4 (DRD4), a receptor associated with cognitive functions. In this study, a DRD4 gene exon III tandem repeat from the order Cetacea was identified and characterized. Included in our study...

Melanocortin systems on pigment dispersion in fish chromatophores.

Science.gov (United States)

Kobayashi, Yuki; Mizusawa, Kanta; Saito, Yumiko; Takahashi, Akiyoshi

2012-01-01

α-Melanocyte-stimulating hormone (α-MSH) is responsible for pigment dispersion in the chromatophores of fish and other tetrapods such as amphibians and reptiles. Recently, we discovered that α-MSH did not always stimulate pigment dispersion because this hormonal peptide exerted no effects on the melanophores of flounders. We assumed that the reduction of α-MSH activity was related to the co-expression of different α-MSH receptor subtypes - termed melanocortin receptors (MCR) - a member of G-protein-coupled receptors (GPCR) - based on several reports demonstrating that GPCR forms heterodimers with various properties that are distinct from those of the corresponding monomers. In this review, we summarize the relationships between the pigment-dispersing activity of α-MSH-related peptides, molecular forms of α-MSH-related peptides, and mcr subtypes expressed in fish chromatophores.

Nuclear Gene Indicates Coat-Color Polymorphism in Mammoths

DEFF Research Database (Denmark)

Römpler, Holger; Rohland, Nadin; Lalueza-Fox, Carles

2006-01-01

By amplifying the melanocortin type 1 receptor from the woolly mammoth, we can report the complete nucleotide sequence of a nuclear-encoded gene from an extinct species. We found two alleles and show that one allele produces a functional protein whereas the other one encodes a protein with strongly...

Melanocortin systems on pigment dispersion in fish chromatophores

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Yuki eKobayashi

2012-02-01

Full Text Available Alpha-Melanocyte-stimulating hormone (alpha-MSH is responsible for pigment dispersion in the chromatophores of fish and other tetrapods such as amphibians and reptiles. Recently, we discovered that alpha-MSH did not always stimulate pigment dispersion because this hormonal peptide exerted no effects on the melanophores of flounders. We assumed that the reduction of alpha-MSH activity was related to the co-expression of different alpha-MSH receptor subtypes—termed melanocortin receptors (MCR—a member of G-protein-coupled receptors (GPCR—based on several reports demonstrating that GPCR forms heterodimers with various properties that are distinct from those of the corresponding monomers. In this review, we summarize the relationships between the pigment-dispersing activity of alpha-MSH-related peptides, molecular forms of alpha-MSH-related peptides, and Mcr subtypes expressed in fish chromatophores.

Functional Characterization of MC1R-TUBB3 Intergenic Splice Variants of the Human Melanocortin 1 Receptor.

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Cecilia Herraiz

Full Text Available The melanocortin 1 receptor gene (MC1R expressed in melanocytes is a major determinant of skin pigmentation. It encodes a Gs protein-coupled receptor activated by α-melanocyte stimulating hormone (αMSH. Human MC1R has an inefficient poly(A site allowing intergenic splicing with its downstream neighbour Tubulin-β-III (TUBB3. Intergenic splicing produces two MC1R isoforms, designated Iso1 and Iso2, bearing the complete seven transmembrane helices from MC1R fused to TUBB3-derived C-terminal extensions, in-frame for Iso1 and out-of-frame for Iso2. It has been reported that exposure to ultraviolet radiation (UVR might promote an isoform switch from canonical MC1R (MC1R-001 to the MC1R-TUBB3 chimeras, which might lead to novel phenotypes required for tanning. We expressed the Flag epitope-tagged intergenic isoforms in heterologous HEK293T cells and human melanoma cells, for functional characterization. Iso1 was expressed with the expected size. Iso2 yielded a doublet of Mr significantly lower than predicted, and impaired intracellular stability. Although Iso1- and Iso2 bound radiolabelled agonist with the same affinity as MC1R-001, their plasma membrane expression was strongly reduced. Decreased surface expression mostly resulted from aberrant forward trafficking, rather than high rates of endocytosis. Functional coupling of both isoforms to cAMP was lower than wild-type, but ERK activation upon binding of αMSH was unimpaired, suggesting imbalanced signaling from the splice variants. Heterodimerization of differentially labelled MC1R-001 with the splicing isoforms analyzed by co-immunoprecipitation was efficient and caused decreased surface expression of binding sites. Thus, UVR-induced MC1R isoforms might contribute to fine-tune the tanning response by modulating MC1R-001 availability and functional parameters.

Transactivation of the proximal promoter of human oxytocin gene by TR4 orphan receptor

International Nuclear Information System (INIS)

Wang, C.-P.; Lee, Y.-F.; Chang, C.; Lee, H.-J.

2006-01-01

The human testicular receptor 4 (TR4) shares structural homology with members of the nuclear receptor superfamily. Some other members of this superfamily were able to regulate the transcriptional activity of the human oxytocin (OXT) promoter by binding to the first DR0 regulatory site. However, little investigation was conducted systematically in the study of the second dDR4 site of OXT proximal promoter, and the relationship between the first and the second sites of OXT promoter. Here, we demonstrated for the first time that TR4 could increase the proximal promoter activity of the human OXT gene via DR0, dDR4, and OXT (both DR0 and dDR4) elements, respectively. TR4 might induce OXT gene expression through the OXT element in a dose-dependent manner. However, there is no synergistic effect between DR0 and dDR4 elements during TR4 transactivation. Taken together, these results suggested that TR4 should be one of important regulators of OXT gene expression

Preclinical evaluation of melanocortin-1 receptor (MC1-R) specific 68Ga- and 44Sc-labeled DOTA-NAPamide in melanoma imaging.

Science.gov (United States)

Nagy, Gábor; Dénes, Noémi; Kis, Adrienn; Szabó, Judit P; Berényi, Ervin; Garai, Ildikó; Bai, Péter; Hajdu, István; Szikra, Dezső; Trencsényi, György

2017-08-30

Alpha melanocyte stimulating hormone (α-MSH) enhances melanogenesis in melanoma malignum by binding to melanocortin-1 receptors (MC1-R). Earlier studies demonstrated that alpha-MSH analog NAPamide molecule specifically binds to MC1-R receptor. Radiolabeled NAPamide is a promising radiotracer for the non-invasive detection of melanin producing melanoma tumors by Positron Emission Tomography (PET). In this present study the MC1-R selectivity of the newly developed Sc-44-labeled DOTA-NAPamide was investigated in vitro and in vivo using melanoma tumors. DOTA-NAPamide was labeled with Ga-68 and Sc-44 radionuclides. The MC1-R specificity of Ga-68- and Sc-44-labeled DOTA-NAPamide was investigated in vitro and in vivo using MC1-R positive (B16-F10) and negative (A375) melanoma cell lines. For in vivo imaging studies B16-F10 and A375 tumor-bearing mice were injected with 44 Sc/ 68 Ga-DOTA-NAPamide (in blocking studies with α-MSH) and whole body PET/MRI scans were acquired. Radiotracer uptake was expressed in terms of standardized uptake values (SUVs). 44 Sc/ 68 Ga-labeled DOTA-NAPamide were produced with high specific activity (approx. 19 GBq/μmol) and with excellent radiochemical purity (99%DOTA-NAPamide (SUVmean: 0.38±0.02), and Sc-44-DOTA-NAPamide (SUVmean: 0.52±0.13) uptake was observed in subcutaneously growing B16-F10 tumors, than in receptor negative A375 tumors, where the SUVmean values of Ga-68-DOTA-NAPamide and Sc-44-DOTA-NAPamide were 0.04±0.01 and 0.07±0.01, respectively. Tumor-to-muscle (T/M SUVmean) ratios were approximately 15-fold higher in B16-F10 tumor-bearing mice, than that of A375 tumors, and this difference was also significant (p≤0.01) using both radiotracers after 60 min incubation time. Our newly synthesized 44 Sc-labeled DOTA-NAPamide probe showed excellent binding properties to melanocortin-1 receptor (MC1-R) positive melanoma cell and tumors. Due to its high specificity and sensitivity 44 Sc-DOTA-NAPamide is a promising radiotracer in

Gender-specific roles for the melanocortin-3 receptor in the regulation of the mesolimbic dopamine system in mice.

Science.gov (United States)

Lippert, Rachel N; Ellacott, Kate L J; Cone, Roger D

2014-05-01

The melanocortin-3 receptor (MC3R) and MC4R are known to play critical roles in energy homeostasis. However, the physiological functions of the MC3R remain poorly understood. Earlier reports indicated that the ventral tegmental area (VTA) is one of the highest sites of MC3R expression, and we sought to determine the function of the receptor in this brain region. A MC3R-green-fluorescent protein transgenic mouse and a MC3R knockout mouse strain were used to characterize the neurochemical identity of the MC3R neurons in the VTA and to determine the effects of global MC3R deletion on VTA dopamine (DA) homeostasis. We demonstrate that the MC3R, but not MC4R, is expressed in up to a third of dopaminergic neurons of the VTA. Global deletion of the MC3R increases total dopamine by 42% in the VTA and decreases sucrose intake and preference in female but not male mice. Ovariectomy restores dopamine levels to normal, but aberrant decreased VTA dopamine levels are also observed in prepubertal female mice. Because arcuate Agouti-related peptide/neuropeptide Y neurons are known to innervate and regulate VTA signaling, the MC3R in dopaminergic neurons provides a specific input for communication of nutritional state within the mesolimbic dopamine system. Data provided here suggest that this input may be highly sexually dimorphic, functioning as a specific circuit regulating effects of estrogen on VTA dopamine levels and on sucrose preference. Overall, this data support a sexually dimorphic function of MC3R in regulation of the mesolimbic dopaminergic system and reward.

Common variants near MC4R in relation to body fat, body fat distribution, metabolic traits and energy expenditure

DEFF Research Database (Denmark)

Kring, Sofia Inez Iqbal; Holst, C; Toubro, Søren

2010-01-01

Common variants near melanocortin receptor 4 (MC4R) have been related to fatness and type 2 diabetes. We examined the associations of rs17782313 and rs17700633 in relation to body fat, body fat distribution, metabolic traits, weight development and energy expenditure.......Common variants near melanocortin receptor 4 (MC4R) have been related to fatness and type 2 diabetes. We examined the associations of rs17782313 and rs17700633 in relation to body fat, body fat distribution, metabolic traits, weight development and energy expenditure....

No linkage and association of atopy to chromosome 16 including the interleukin-4 receptor gene

DEFF Research Database (Denmark)

Haagerup, A; Bjerke, T; Schiøtz, P O

2001-01-01

BACKGROUND: Several susceptibility genes for atopy have been suggested in recent years. Few have been investigated as intensively as the interleukin-4-receptor alpha (IL4Ralpha) gene on chromosome 16. The results remain in dispute. Therefore, in a robust design, we tested for association of type ...

Pharmacological characterization of 30 human melanocortin-4 receptor polymorphisms with the endogenous proopiomelanocortin-derived agonists, synthetic agonists, and the endogenous agouti-related protein antagonist.

Science.gov (United States)

Xiang, Zhimin; Proneth, Bettina; Dirain, Marvin L; Litherland, Sally A; Haskell-Luevano, Carrie

2010-06-08

The melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic biomarker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and nonobese controls. Many significant studies have been performed examining the pharmacological characteristics of these hMC4R SNPs in attempts to identify a molecular defects/insights that might link a genetic factor to the obese phenotype observed in patients possessing these mutations. Our laboratory has previously reported the pharmacological characterization of 40 of these polymorphic hMC4 receptors with multiple endogenous and synthetic ligands. The goal of the current study is to perform a similar comprehensive side-by-side characterization of 30 additional human hMC4R with single nucleotide polymorphisms using multiple endogenous agonists [alpha-, beta-, and gamma(2)-melanocyte stimulating hormones (MSH) and adrenocorticotropin (ACTH)], the antagonist agouti-related protein hAGRP(87-132), and synthetic agonists [NDP-MSH, MTII, and the tetrapeptide Ac-His-dPhe-Arg-Trp-NH(2) (JRH887-9)]. These in vitro data, in some cases, provide a putative molecular link between dysfunctional hMC4R's and human obesity. These 30 hMC4R SNPs include R7H, R18H, R18L, S36Y, P48S, V50M, F51L, E61K, I69T, D90N, S94R, G98R, I121T, A154D, Y157S, W174C, G181D, F202L, A219 V, I226T, G231S, G238D, N240S, C271R, S295P, P299L, E308K, I317V, L325F, and 750DelGA. All but the N240S hMC4R were identified in obese patients. Additionally, we have characterized a double I102T/V103I hMC4R. In addition to the pharmacological characterization, the hMC4R variants were evaluated for cell surface

A preliminary study on the association of single nucleotide polymorphisms of interleukin 4 (IL4, IL13, IL4 receptor alpha (IL4Rα & Toll-like receptor 4 (TLR4 genes with asthma in Indian adults

Directory of Open Access Journals (Sweden)

Parisa Davoodi

2015-01-01

Full Text Available Background & objectives: Interleukin 4 (IL4 and IL13 genes are believed to be responsible for inflammation of the airways in asthmatics. These share a common receptor component called IL4Rα which is another potentially important candidate gene linked to asthma phenotypes. Another gene Toll-like receptor 4 (TLR4 might affect the incidence or progression of asthma through the expression of proinflammatory genes. Several single nucleotide polymorphisms (SNPs in IL4, IL13, IL4Rα and TLR4 have been reported to be linked to asthma or related phenotypes in several ethnic populations using linkage studies and association studies. However, the results have not been consistent. We investigated five SNPs (C-589T and C-33T of IL4, G+2044A of IL13, A+1902G of IL4Rα, and A+896G of TLR4 in patients with adult onset asthma to evaluate their role in manifestation and severity of asthma. Methods: Adult (>18 yr of age patients with asthma (n=100 and healthy controls (n=50 were included in the study. Genotyping was performed using sequenom MassARRAY technology. Results: The mutant alleles of the C-589T and C-33T SNPs in the promoter region of IL4 were present in 4 per cent patients with asthma but absent from the control group suggesting that the variations in IL4 may contribute to asthma occurrence. The SNPs of other genes were seen in both controls and patients. Interpretation & conclusions: The results suggest the possible association between the genetic distribution of C-589T and C-33T SNPs of IL4 with asthma in Indian adults.

Adrenocorticotropic Hormone (ACTH) Responses Require Actions of the Melanocortin-2 Receptor Accessory Protein on the Extracellular Surface of the Plasma Membrane.

Science.gov (United States)

Malik, Sundeep; Dolan, Terrance M; Maben, Zachary J; Hinkle, Patricia M

2015-11-13

The melanocortin-2 (MC2) receptor is a G protein-coupled receptor that mediates responses to ACTH. The MC2 receptor acts in concert with the MC2 receptor accessory protein (MRAP) that is absolutely required for ACTH binding and signaling. MRAP has a single transmembrane domain and forms a highly unusual antiparallel homodimer that is stably associated with MC2 receptors at the plasma membrane. Despite the physiological importance of the interaction between the MC2 receptor and MRAP, there is little understanding of how the accessory protein works. The dual topology of MRAP has made it impossible to determine whether highly conserved and necessary regions of MRAP are required on the intracellular or extracellular face of the plasma membrane. The strategy used here was to fix the orientation of two antiparallel MRAP molecules and then introduce inactivating mutations on one side of the membrane or the other. This was achieved by engineering proteins containing tandem copies of MRAP fused to the amino terminus of the MC2 receptor. The data firmly establish that only the extracellular amino terminus (Nout) copy of MRAP, oriented with critical segments on the extracellular side of the membrane, is essential. The transmembrane domain of MRAP is also required in only the Nout orientation. Finally, activity of MRAP-MRAP-MC2-receptor fusion proteins with inactivating mutations in either MRAP or the receptor was rescued by co-expression of free wild-type MRAP or free wild-type receptor. These results show that the basic MRAP-MRAP-receptor signaling unit forms higher order complexes and that these multimers signal. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Pharmacological Characterization of 30 Human Melanocortin-4 Receptor Polymorphisms with the Endogenous Proopiomelanocortin Derived Agonists, Synthetic Agonists, and the Endogenous Agouti-Related Protein (AGRP) Antagonist

Science.gov (United States)

Xiang, Zhimin; Proneth, Bettina; Dirain, Marvin L.; Litherland, Sally A.; Haskell-Luevano, Carrie

2010-01-01

The melanocortin-4 receptor (MC4R) is a G-protein coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic bio marker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and non-obese controls. Many significant studies have been performed examining the pharmacological characteristics of these hMC4R SNPs in attempts to identify a molecular defects/insights that might link a genetic factor to the obese phenotype observed in patients possessing these mutations. Our laboratory has previously reported the pharmacological characterization of 40 of these polymorphic hMC4 receptors with multiple endogenous and synthetic ligands. The goal of the current study is to perform a similar comprehensive side-by-side characterization of 30 additional human hMC4R with single nucleotide polymorphisms using multiple endogenous agonists [α-, β, γ2-melanocyte stimulating hormones (MSH) and adrenocorticotropin (ACTH)], the antagonist agouti-related protein hAGRP(87-132), and synthetic agonists [NDP-MSH, MTII, and the tetrapeptide Ac-His-DPhe-Arg-Trp-NH2 (JRH887-9)]. These in vitro data, in some cases, provide a putative molecular link between dysfunctional hMC4R's and human obesity. These 30 hMC4R SNPs include R7H, R18H, R18L, S36Y, P48S, V50M, F51L, E61K, I69T, D90N, S94R, G98R, I121T, A154D, Y157S, W174C, G181D, F202L, A219V, I226T, G231S, G238D, N240S, C271R, S295P, P299L, E308K, I317V, L325F and 750DelGA. All but the N240S hMC4R were identified in obese patients. Additionally, we have characterized a double I102T/V103I hMC4R. In addition to the pharmacological characterization, the hMC4R variants were evaluated for cell surface expression by flow

Melanocortin 1 Receptor Deficiency Promotes Atherosclerosis in Apolipoprotein E-/- Mice.

Science.gov (United States)

Rinne, Petteri; Kadiri, James J; Velasco-Delgado, Mauricio; Nuutinen, Salla; Viitala, Miro; Hollmén, Maija; Rami, Martina; Savontaus, Eriika; Steffens, Sabine

2018-02-01

The MC1-R (melanocortin 1 receptor) is expressed by monocytes and macrophages where it mediates anti-inflammatory actions. MC1-R also protects against macrophage foam cell formation primarily by promoting cholesterol efflux through the ABCA1 (ATP-binding cassette transporter subfamily A member 1) and ABCG1 (ATP-binding cassette transporter subfamily G member 1). In this study, we aimed to investigate whether global deficiency in MC1-R signaling affects the development of atherosclerosis. Apoe -/- (apolipoprotein E deficient) mice were crossed with recessive yellow (Mc1r e/e ) mice carrying dysfunctional MC1-R and fed a high-fat diet to induce atherosclerosis. Apoe -/- Mc1r e/e mice developed significantly larger atherosclerotic lesions in the aortic sinus and in the whole aorta compared with Apoe -/- controls. In terms of plaque composition, MC1-R deficiency was associated with less collagen and smooth muscle cells and increased necrotic core, indicative of more vulnerable lesions. These changes were accompanied by reduced Abca1 and Abcg1 expression in the aorta. Furthermore, Apoe -/- Mc1r e/e mice showed a defect in bile acid metabolism that aggravated high-fat diet-induced hypercholesterolemia and hepatic lipid accumulation. Flow cytometric analysis of leukocyte profile revealed that dysfunctional MC1-R enhanced arterial accumulation of classical Ly6C high monocytes and macrophages, effects that were evident in mice fed a normal chow diet but not under high-fat diet conditions. In support of enhanced arterial recruitment of Ly6C high monocytes, these cells had increased expression of L-selectin and P-selectin glycoprotein ligand 1. The present study highlights the importance of MC1-R in the development of atherosclerosis. Deficiency in MC1-R signaling exacerbates atherosclerosis by disturbing cholesterol handling and by increasing arterial monocyte accumulation. © 2017 The Authors.

Disseminated cysticercosis: clinical spectrum, Toll-like receptor-4 gene polymorphisms and role of albendazole

Science.gov (United States)

Qavi, Abdul; Garg, Ravindra Kumar; Malhotra, Hardeep Singh; Jain, Amita; Kumar, Neeraj; Malhotra, Kiran Preet; Srivastava, Pradeep Kumar; Verma, Rajesh; Sharma, Praveen Kumar

2016-01-01

Abstract In this study, we describe clinical and imaging spectrum, and the natural course of patients with disseminated cysticercosis. How albendazole affects the course of disease has also been evaluated. We assessed the Toll-like receptor-4 gene polymorphisms, to know the reason for the apparently higher prevalence of disseminated cysticercosis in India. Sixty consecutive patients with disseminated cysticercosis were enrolled. Sixty age-and-sex-matched healthy controls were also enrolled for the purpose of genetic study. Twenty patients, who gave consent, were treated with albendazole along with corticosteroids. Forty patients did not give consent for antiparasitic therapy. Assessment for Toll-like receptor-4 gene polymorphisms (Asp299Gly and Thr399Ile genes) was done. Patients were followed for 6 months. We also performed a literature search of cases published in English language using PubMed electronic database and analyzed 56 cases thus available. There was an increased risk (6.63 fold and 4.61 fold) of disseminated cysticercosis in the presence of Asp299Gly and Thr399Ile polymorphisms in Toll-like receptor-4, respectively. The allelic frequency of Gly (11% vs. 3%, P = 0.024, odds ratio [OR] = 3.52) and Ile alleles (11% vs. 2%, P = 0.009, OR = 4.738) in disseminated cysticercosis was high. Albendazole resulted in complete disappearance of all cerebral lesions in 35% (7/20) patients and reduction in lesion load in remaining 65% (13/20) patients. No significant change in number of cysticercal lesion was noted in patients who did not receive albendazole. No major adverse reaction following antiparasitic treatment was noted. Three deaths were recorded in patients who did not receive antiparasitic treatment. Of the 56 cases reported in PubMed, 33 patients received antiparasitic treatment with follow-up data available for 31 patients. Most (24) of these patients received albendazole. A significant clinical and/or imaging improvements, on follow up, were observed in

Functional hypothalamic amenorrhea due to increased CRH tone in melanocortin receptor 2-deficient mice.

Science.gov (United States)

Matsuwaki, Takashi; Nishihara, Masugi; Sato, Tsuyoshi; Yoda, Tetsuya; Iwakura, Yoichiro; Chida, Dai

2010-11-01

Exposure to chronic stressors results in dysregulation of the hypothalamic-pituitary-adrenal axis and a disruption in reproduction. CRH, the principal regulator of the hypothalamic-pituitary-adrenal axis induces the secretion of ACTH from the pituitary, which stimulates adrenal steroidogenesis via the specific cell-surface melanocortin 2 receptor (MC2R). Previously, we demonstrated that MC2R(-/-) mice had undetectable levels of corticosterone despite high ACTH levels. Here, we evaluated the reproductive functions of female MC2R(-/-) mice and analyzed the mechanism of the disrupted cyclicity of these mice. The expression of CRH in the paraventricular nucleus was significantly increased in MC2R(-/-) mice under nonstressed conditions. Although MC2R(-/-) females were fertile, they showed a prolonged estrous cycle. After hormonal stimulation, MC2R(-/-) females produced nearly-normal numbers of eggs, but slightly less than MC2R(+/-) females, and showed near-normal ovarian histology. During diestrus, the number of GnRH-positive cells in the medial preoptic area was significantly reduced in MC2R(-/-) females. CRH type 1 receptor antagonist restored estrous cyclicity in MC2R(-/-) females. Kisspeptin-positive areas in the arcuate nucleus were comparable, whereas kisspeptin-positive areas in the anteroventral periventricular nucleus in MC2R(-/-) females were significantly reduced compared with MC2R(+/-) females, suggesting that arcuate nucleus kisspeptin is not involved, but anteroventral periventricular nucleus kisspeptin may be involved, in the maintenance of estrous cyclicity. Our findings show that high levels of hypothalamic CRH disturb estrous cyclicity in the female animals and that the MC2R(-/-) female is a unique animal model of functional hypothalamic amenorrhea.

G protein-coupled receptor mutations and human genetic disease.

Science.gov (United States)

Thompson, Miles D; Hendy, Geoffrey N; Percy, Maire E; Bichet, Daniel G; Cole, David E C

2014-01-01

Genetic variations in G protein-coupled receptor genes (GPCRs) disrupt GPCR function in a wide variety of human genetic diseases. In vitro strategies and animal models have been used to identify the molecular pathologies underlying naturally occurring GPCR mutations. Inactive, overactive, or constitutively active receptors have been identified that result in pathology. These receptor variants may alter ligand binding, G protein coupling, receptor desensitization and receptor recycling. Receptor systems discussed include rhodopsin, thyrotropin, parathyroid hormone, melanocortin, follicle-stimulating hormone (FSH), luteinizing hormone, gonadotropin-releasing hormone (GNRHR), adrenocorticotropic hormone, vasopressin, endothelin-β, purinergic, and the G protein associated with asthma (GPRA or neuropeptide S receptor 1 (NPSR1)). The role of activating and inactivating calcium-sensing receptor (CaSR) mutations is discussed in detail with respect to familial hypocalciuric hypercalcemia (FHH) and autosomal dominant hypocalemia (ADH). The CASR mutations have been associated with epilepsy. Diseases caused by the genetic disruption of GPCR functions are discussed in the context of their potential to be selectively targeted by drugs that rescue altered receptors. Examples of drugs developed as a result of targeting GPCRs mutated in disease include: calcimimetics and calcilytics, therapeutics targeting melanocortin receptors in obesity, interventions that alter GNRHR loss from the cell surface in idiopathic hypogonadotropic hypogonadism and novel drugs that might rescue the P2RY12 receptor congenital bleeding phenotype. De-orphanization projects have identified novel disease-associated receptors, such as NPSR1 and GPR35. The identification of variants in these receptors provides genetic reagents useful in drug screens. Discussion of the variety of GPCRs that are disrupted in monogenic Mendelian disorders provides the basis for examining the significance of common

Polymorphisms and haplotypes in the bovine neuropeptide Y, growth hormone receptor, ghrelin, insulin-like growth factor 2, and uncoupling proteins 2 and 3 genes and their associations with measures of growth, performance, feed efficiency, and carcass merit in beef cattle.

Science.gov (United States)

Sherman, E L; Nkrumah, J D; Murdoch, B M; Li, C; Wang, Z; Fu, A; Moore, S S

2008-01-01

Genes that regulate metabolism and energy partitioning have the potential to influence economically important traits in farm animals, as do polymorphisms within these genes. In the current study, SNP in the bovine neuropeptide Y (NPY), growth hormone receptor (GHR), ghrelin (GHRL), uncoupling proteins 2 and 3 (UCP2 and UCP3), IGF2, corticotrophin-releasing hormone (CRH), cocaine and amphetamine regulated transcript (CART), melanocortin-4 receptor (MC4R), proopiomelanocortin (POMC), and GH genes were evaluated for associations with growth, feed efficiency, and carcass merit in beef steers. In total, 24 SNP were evaluated for associations with these traits and haplotypes were constructed within each gene when 2 or more SNP showed significant associations. An A/G SNP located in intron 4 of the GHR gene had the largest effects on BW of the animals (dominance effect P GHRL gene tended to show effects on residual feed intake, FCR, and partial efficiency of growth (P < 0.10). The IGF2 SNP most strongly affected LM area (P < 0.01), back fat, ADG, and FCR (P < 0.05). The SNP in the CART, MC4R, POMC, GH, and CRH genes did not show associations at P < 0.05 with any of the traits. Although most of the SNP that showed associations do not cause amino acid changes, these SNP could be linked to other yet to be detected causative mutations or nearby QTL. It will be very important to verify these results in other cattle populations.

NR4A nuclear receptors mediate carnitine palmitoyltransferase 1A gene expression by the rexinoid HX600

Energy Technology Data Exchange (ETDEWEB)

Ishizawa, Michiyasu [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan); Kagechika, Hiroyuki [Graduate School of Biomedical Science, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Makishima, Makoto, E-mail: makishima.makoto@nihon-u.ac.jp [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan)

2012-02-24

Highlights: Black-Right-Pointing-Pointer The function of RXR heterodimers with NR4 receptors remains unknown. Black-Right-Pointing-Pointer The RXR ligand HX600 induces expression of carnitine palmitoyltransferase 1A (CPT1A). Black-Right-Pointing-Pointer HX600-induced CPT1A expression is mediated by the NR4 receptors, Nur77 and NURR1. Black-Right-Pointing-Pointer CPT1A induction by HX600 is not mediated by de novo protein synthesis. Black-Right-Pointing-Pointer CPT1A could be a target of the Nur77-RXR and NURR1-RXR heterodimers. -- Abstract: Retinoid X receptors (RXRs) are members of the nuclear receptor superfamily and can be activated by 9-cis retinoic acid (9CRA). RXRs form homodimers and heterodimers with other nuclear receptors such as the retinoic acid receptor and NR4 subfamily nuclear receptors, Nur77 and NURR1. Potential physiological roles of the Nur77-RXR and NURR1-RXR heterodimers have not been elucidated. In this study, we identified a gene regulated by these heterodimers utilizing HX600, a selective RXR agonist for Nur77-RXR and NURR1-RXR. While 9CRA induced many genes, including RAR-target genes, HX600 effectively induced only carnitine palmitoyltransferase 1A (CPT1A) in human teratocarcinoma NT2/D1 cells, which express RXR{alpha}, Nur77 and NURR1. HX600 also increased CPT1A expression in human embryonic kidney (HEK) 293 cells and hepatocyte-derived HepG2 cells. Although HX600 induced CPT1A less effectively than 9CRA, overexpression of Nur77 or NURR1 increased the HX600 response to levels similar to 9CRA in NT2/D1 and HEK293 cells. A dominant-negative form of Nur77 or NURR1 repressed the induction of CPT1A by HX600. A protein synthesis inhibitor did not alter HX600-dependent CPT1A induction. Thus, the rexinoid HX600 directly induces expression of CPT1A through a Nur77 or NURR1-mediated mechanism. CPT1A, a gene involved in fatty acid {beta}-oxidation, could be a target of RXR-NR4 receptor heterodimers.

Symptoms of Attention-Deficit/Hyperactivity Disorder in Down Syndrome: Effects of the Dopamine Receptor D4 Gene

Science.gov (United States)

Mason, Gina Marie; Spanó, Goffredina; Edgin, Jamie

2015-01-01

This study examined individual differences in ADHD symptoms and executive function (EF) in children with Down syndrome (DS) in relation to the dopamine receptor D4 (DRD4) gene, a gene often linked to ADHD in people without DS. Participants included 68 individuals with DS (7-21 years), assessed through laboratory tasks, caregiver reports, and…

NMR Insights into the Structure-Function Relationships in the Binding of Melanocortin Analogues to the MC1R Receptor.

Science.gov (United States)

Morais, Maurício; Zamora-Carreras, Héctor; Raposinho, Paula D; Oliveira, Maria Cristina; Pantoja-Uceda, David; Correia, João D G; Jiménez, M Angeles

2017-07-15

Linear and cyclic analogues of the α-melanocyte stimulating hormone (α-MSH) targeting the human melanocortin receptor 1 (MC1R) are of pharmacological interest for detecting and treating melanoma. The central sequence of α-MSH (His-Phe-Arg-Trp) has been identified as being essential for receptor binding. To deepen current knowledge on the molecular basis for α-MSH bioactivity, we aimed to understand the effect of cycle size on receptor binding. To that end, we synthesised two macrocyclic isomeric α-MSH analogues, c[NH-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Lys]-Lys-NH₂ ( CycN-K6 ) and c[NH-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Lys-Lys]-NH₂ ( CycN-K7 ). Their affinities to MC1R receptor were determined by competitive binding assays, and their structures were analysed by ¹H and 13 C NMR. These results were compared to those of the previously reported analogue c[S-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Cys]-Lys-NH₂ ( CycS-C6 ). The MC1R binding affinity of the 22-membered macrocyclic peptide CycN-K6 (IC 50 = 155 ± 16 nM) is higher than that found for the 25-membered macrocyclic analogue CycN-K7 (IC 50 = 495 ± 101 nM), which, in turn, is higher than that observed for the 19-membered cyclic analogue CycS-C6 (IC 50 = 1770 ± 480 nM). NMR structural study indicated that macrocycle size leads to changes in the relative dispositions of the side chains, particularly in the packing of the Arg side chain relative to the aromatic rings. In contrast to the other analogues, the 22-membered cycle's side chains are favorably positioned for receptor interaction.

Inhibitory Effect of the Melanocortin Receptor Agonist Melanotan-II (MTII) on Feeding Depends on Dietary Fat Content and not Obesity in Rats on Free-Choice Diets

NARCIS (Netherlands)

van den Heuvel, José K; Eggels, Leslie; van Rozen, Andrea J; Fliers, Eric; Kalsbeek, Andries; Adan, Roger A H; la Fleur, Susanne E

2015-01-01

INTRODUCTION: Conflicting data exist on sensitivity changes of the melanocortin system during diet-induced obesity. We hypothesized that melanocortin sensitivity depends on diet composition, in particular on the fat content rather than the level of obesity. The aim of this study was to determine the

Growth and gene expression are predominantly controlled by distinct regions of the human IL-4 receptor.

Science.gov (United States)

Ryan, J J; McReynolds, L J; Keegan, A; Wang, L H; Garfein, E; Rothman, P; Nelms, K; Paul, W E

1996-02-01

IL-4 causes hematopoietic cells to proliferate and express a series of genes, including CD23. We examined whether IL-4-mediated growth, as measured by 4PS phosphorylation, and gene induction were similarly controlled. Studies of M12.4.1 cells expressing human IL-4R truncation mutants indicated that the region between amino acids 557-657 is necessary for full gene expression, which correlated with Stat6 DNA binding activity. This region was not required for 4PS phosphorylation. Tyrosine-to-phenylalanine mutations in the interval between amino acids 557-657 revealed that as long as one tyrosine remained unmutated, CD23 was fully induced. When all three tyrosines were mutated, the receptor was unable to induce CD23. The results indicate that growth regulation and gene expression are principally controlled by distinct regions of IL-4R.

Neuropeptide Y receptor genes on human chromosome 4q31-q32 map to conserved linkage groups on mouse chromosomes 3 and 8

Energy Technology Data Exchange (ETDEWEB)

Lutz, C.M.; Frankel, W.N. [Jackson Lab., Bar Harbor, ME (United States); Richards, J.E. [Univ. of Michigan Medical School, Ann Arbor, MI (United States)] [and others

1997-05-01

Npy1r and Npy2r, the genes encoding mouse type 1 and type 2 neuropeptide Y receptors, have been mapped by interspecific backcross analysis. Previous studies have localized the human genes encoding these receptors to chromosome 4q31-q32. We have now assigned Npy1r and Npy2r to conserved linkage groups on mouse Chr 8 and Chr 3, respectively, which correspond to the distal region of human chromosome 4q. Using yeast artificial chromosomes, we have estimated the distance between the human genes to be approximately 6 cM. Although ancient tandem duplication events may account for some closely spaced G-protein-coupled receptor genes, the large genetic distance between the human type 1 and type 2 neuropeptide Y receptor genes raises questions about whether this mechanism accounts for their proximity. 20 refs., 1 fig.

A Study of the Impact of Death Receptor 4 (DR4) Gene Polymorphisms in Alzheimer's Disease.

Science.gov (United States)

Edgünlü, Tuba Gökdoğan; Ozge, Aynur; Yalın, Osman Özgür; Kul, Seval; Erdal, Mehmet Emin

2013-09-01

Excessive apoptosis is believed to play a role in many degenerative and non-degenerative neurological diseases including Alzheimer's disease (AD). Much recent data suggest that apoptotic mechanisms may represent the missing link between Aβ deposition and proteolysis of tau protein. However, there is emerging evidence that apoptotic mechanisms may play a role in Alzheimer's Disease pathogenesis in the absence of overt apoptosis. TNF-related apoptosis inducing ligand receptor 1 (Death Receptor 4, DR4) might impair the apoptotic signal transduction and lead to dysregulation of the homeostasis between cell survival and cell death. The aim of our study was to further investigate the relationship between genetic variants of DR4 and Alzheimer's Disease. Case control study. Sixty-eight patients with AD were included in the study. The control group comprised 72 subjects without signs of neurodegenerative diseases, as evidenced by the examination.DNA was extracted from whole blood using the salting-out procedure. Genotypes were identified by restriction fragment length polymorphism analysis of polymerase chain reaction (PCR-RFLP) products. We observed significant differences in the genotypic distribution of the rs6557634 polymorphism in AD patients compared with controls (p0.05) and the DR4 rs20576 polymorphism (p>0.05). According to haplotype analysis of the DR4 gene for rs6557634, rs20575 and rs20576 polymorphisms, GCA and GCC haplotypes might be a risk factor for AD. Also, we have shown that ACA, GGC and GGA haplotypes might be protective factors against AD. The present results indicate for the first time the possible contribution of the DR4 gene rs6557634, rs20575, rs20576 polymorphisms in Alzheimer's Disease, which may influence susceptibility to Alzheimer's Disease.

Lack of death receptor 4 (DR4) expression through gene promoter methylation in gastric carcinoma.

Science.gov (United States)

Lee, Kyung Hwa; Lim, Sang Woo; Kim, Ho Gun; Kim, Dong Yi; Ryu, Seong Yeob; Joo, Jae Kyun; Kim, Jung Chul; Lee, Jae Hyuk

2009-07-01

To determine the underlying mechanism for the differential expression, the extent of promoter methylation in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-related genes acting downstream of TRAIL was examined in early and advanced gastric carcinomas. The extent of promoter methylation in the DR4, DR5, DcR1, DcR2, and CASP8 genes was quantified using bisulfite modification and methylation-specific polymerase chain reaction. The promoters for DcR1, DcR2, and CASP8 were largely unmethylated in early gastric carcinoma, advanced gastric carcinoma, and controls, with no significant difference among them. Protein levels of DR4, DcR1, and DcR2 as revealed by immunohistochemistry correlated with the extent of the respective promoter methylation (P < 0.05 in all cases). Hypomethylation, rather than hypermethylation, of the DR4 promoter was noted in invasive gastric malignancies, with statistical significance (P = 0.003). The promoter methylation status of TRAIL receptors in gastric carcinoma may have clinical implications for improving therapeutic strategies in patients with gastric carcinoma.

Polymorphisms in the dopamine D4 receptor gene (DRD4) contribute to individual differences in human sexual behavior: desire, arousal and sexual function.

Science.gov (United States)

Ben Zion, I Z; Tessler, R; Cohen, L; Lerer, E; Raz, Y; Bachner-Melman, R; Gritsenko, I; Nemanov, L; Zohar, A H; Belmaker, R H; Benjamin, J; Ebstein, R P

2006-08-01

Although there is some evidence from twin studies that individual differences in sexual behavior are heritable, little is known about the specific molecular genetic design of human sexuality. Recently, a specific dopamine D4 receptor (DRD4) agonist was shown in rats to induce penile erection through a central mechanism. These findings prompted us to examine possible association between the well-characterized DRD4 gene and core phenotypes of human sexual behavior that included desire, arousal and function in a group of 148 nonclinical university students. We observed association between the exon 3 repeat region, and the C-521T and C-616G promoter region SNPs, with scores on scales that measure human sexual behavior. The single most common DRD4 5-locus haplotype (19%) was significantly associated with Desire, Function and Arousal scores. The current results are consistent with animal studies that show a role for dopamine and specifically the DRD4 receptor in sexual behavior and suggest that one pathway by which individual variation in human desire, arousal and function are mediated is based on allelic variants coding for differences in DRD4 receptor gene expression and protein concentrations in key brain areas.

The dopamine D4 receptor gene (DRD4) moderates cultural difference in independent versus interdependent social orientation.

Science.gov (United States)

Kitayama, Shinobu; King, Anthony; Yoon, Carolyn; Tompson, Steve; Huff, Sarah; Liberzon, Israel

2014-06-01

Prior research suggests that cultural groups vary on an overarching dimension of independent versus interdependent social orientation, with European Americans being more independent, or less interdependent, than Asians. Drawing on recent evidence suggesting that the dopamine D4 receptor gene (DRD4) plays a role in modulating cultural learning, we predicted that carriers of DRD4 polymorphisms linked to increased dopamine signaling (7- or 2-repeat alleles) would show higher levels of culturally dominant social orientations, compared with noncarriers. European Americans and Asian-born Asians (total N = 398) reported their social orientation on multiple scales. They were also genotyped for DRD4. As in earlier work, European Americans were more independent, and Asian-born Asians more interdependent. This cultural difference was significantly more pronounced for carriers of the 7- or 2-repeat alleles than for noncarriers. Indeed, no cultural difference was apparent among the noncarriers. Implications for potential coevolution of genes and culture are discussed. © The Author(s) 2014.

Melanocortin 1 receptor-signaling deficiency results in an articular cartilage phenotype and accelerates pathogenesis of surgically induced murine osteoarthritis.

Science.gov (United States)

Lorenz, Julia; Seebach, Elisabeth; Hackmayer, Gerit; Greth, Carina; Bauer, Richard J; Kleinschmidt, Kerstin; Bettenworth, Dominik; Böhm, Markus; Grifka, Joachim; Grässel, Susanne

2014-01-01

Proopiomelanocortin-derived peptides exert pleiotropic effects via binding to melanocortin receptors (MCR). MCR-subtypes have been detected in cartilage and bone and mediate an increasing number of effects in diathrodial joints. This study aims to determine the role of MC1-receptors (MC1) in joint physiology and pathogenesis of osteoarthritis (OA) using MC1-signaling deficient mice (Mc1re/e). OA was surgically induced in Mc1re/e and wild-type (WT) mice by transection of the medial meniscotibial ligament. Histomorphometry of Safranin O stained articular cartilage was performed with non-operated controls (11 weeks and 6 months) and 4/8 weeks past surgery. µCT-analysis for assessing epiphyseal bone architecture was performed as a longitudinal study at 4/8 weeks after OA-induction. Collagen II, ICAM-1 and MC1 expression was analysed by immunohistochemistry. Mc1re/e mice display less Safranin O and collagen II stained articular cartilage area compared to WT prior to OA-induction without signs of spontaneous cartilage surface erosion. This MC1-signaling deficiency related cartilage phenotype persisted in 6 month animals. At 4/8 weeks after OA-induction cartilage erosions were increased in Mc1re/e knees paralleled by weaker collagen II staining. Prior to OA-induction, Mc1re/e mice do not differ from WT with respect to bone parameters. During OA, Mc1re/e mice developed more osteophytes and had higher epiphyseal bone density and mass. Trabecular thickness was increased while concomitantly trabecular separation was decreased in Mc1re/e mice. Numbers of ICAM-positive chondrocytes were equal in non-operated 11 weeks Mc1re/e and WT whereas number of positive chondrocytes decreased during OA-progression. Unchallenged Mc1re/e mice display smaller articular cartilage covered area without OA-related surface erosions indicating that MC1-signaling is critical for proper cartilage matrix integrity and formation. When challenged with OA, Mc1re/e mice develop a more severe OA

Effect of corticosterone on gene expression of feed intake regulatory peptides in laying hens.

Science.gov (United States)

Liu, Lei; Song, Zhigang; Sheikhahmadi, Ardashir; Jiao, Hongchao; Lin, Hai

2012-08-01

The present study was conducted to explore the effects of corticosterone (CORT) on the regulation of appetite-associated genes in laying hens. Forty eight laying hens were randomly divided into two groups: one received subcutaneous injection of CORT (2mg/kg body weight, CORT-exposed) and the other received sham-treatment (Control). Treatment of hens with CORT stimulated an increase (P0.05) on the mRNA levels of neuropeptide Y (NPY), corticotropin-releasing hormone (CRH), melanocortin receptor 4 and 5 (MCR-4 and MCR-5) and cholecystokinin (CCK) in the hypothalamus when compared with control hens. However, the expression of pro-opiomelanocortin (POMC), agouti-related protein (AgRP) and melanocortin recepter 1 (MCR-1) were significantly (Phens. Treatment of laying hens with CORT had no significant (P>0.05) effect on the mRNA levels of CCK in the glandular stomach and the duodenum, and those of ghrelin in the glandular stomach, the duodenum and the jejunum. However, the mRNA levels of CCK in the jejunum and the ileum, and those of ghrelin in the ileum were significantly (Pfeeding status of CORT-exposed laying hens. Copyright © 2012 Elsevier Inc. All rights reserved.

Melatonin Receptor Genes in Vertebrates

Directory of Open Access Journals (Sweden)

Hua Dong Yin

2013-05-01

Full Text Available Melatonin receptors are members of the G protein-coupled receptor (GPCR family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A and MT2 (or Mel1b or MTNR1B receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C, has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.

Nicotinic Acetylcholine Receptor α4 Subunit Gene Variation Associated with Attention Deficit Hyperactivity Disorder

Institute of Scientific and Technical Information of China (English)

HUANG Xuezhu; XU Yong; LI Qianqian; LIU Pozi; YANG Yuan; ZHANG Fuquan; GUO Tianyou; YANG Chuang; GUO Lanting

2009-01-01

Previous pharmacological, human genetics, and animal models have implicated the nicotinic ace-tylcholine receptor a4 subunit (CHRNA4) gene in the pathogenesis of attention deficit/hyperactivity disorder (ADHD). The objective of this study is to examine the genetic association between single nucleotide poly-morphisms in the CHRNA4 gene (rs2273502, rs1044396, rs1044397, and rs3827020 loci) and ADHD. Both case-control and family-based designs are used. Children aged 6 to 16 years were interviewed and as-sessed with the children behavior checklist and the revised conner' parent rating scale to identify probands. No significant differences in the frequency distribution of genotypes or alleles were found between the case and control groups. However, further haplotype analyses showed the CCGG haplotype on dsk for ADHD in 164 case-control samples and the standard transmission disequilibrium test analyses suggest that the allele C of rs2273502 was over-transferred in 98 ADHD parent-offspring tdos. These findings suggest that the CHRNA4 gene may play a role in the pathogenesis of ADHD.

NCBI nr-aa BLAST: CBRC-ACAR-01-0066 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-ACAR-01-0066 gb|AAT90207.1| melanocortin 1 receptor [Holbrookia maculata] gb|AAT90208.1| mela...nocortin 1 receptor [Holbrookia maculata] gb|AAT90209.1| melanocortin 1 receptor [Holbrookia ...maculata] gb|AAT90210.1| melanocortin 1 receptor [Holbrookia maculata] gb|AAT90211.1| melanocortin 1 recepto...r [Holbrookia maculata] gb|AAT90213.1| melanocortin 1 receptor [Holbrookia maculata] gb|AAT90214.1| mela...nocortin 1 receptor [Holbrookia maculata] gb|AAT90215.1| melanocortin 1 receptor [Hol

Reduced anorexigenic efficacy of leptin, but not of the melanocortin receptor agonist melanotan-II, predicts diet-induced obesity in rats

NARCIS (Netherlands)

van Dijk, G; de Vries, K; Nyakas, C; Buwalda, B; Adage, T; Kuipers, F; Kas, M.J.H.; Adan, RAH; Wilkinson, CW; Thiele, TE; Scheurink, AJW

2005-01-01

Leptin gains access to the central nervous system where it influences activity of neuronal networks involved in ingestive behavior, neuroendocrine activity, and metabolism. In particular, the brain melanocortin (MC) system is important in leptin signaling and maintenance of energy balance. Although

Polymorphism and methylation of the MC4R gene in obese and non-obese dogs.

Science.gov (United States)

Mankowska, Monika; Nowacka-Woszuk, Joanna; Graczyk, Aneta; Ciazynska, Paulina; Stachowiak, Monika; Switonski, Marek

2017-08-01

The dog is considered to be a useful biomedical model for human diseases and disorders, including obesity. One of the numerous genes associated with human polygenic obesity is MC4R, encoding the melanocortin 4 receptor. The aim of our study was to analyze polymorphisms and methylation of the canine MC4R in relation to adiposity. Altogether 270 dogs representing four breeds predisposed to obesity: Labrador Retriever (n = 187), Golden Retriever (n = 38), Beagle (n = 28) and Cocker Spaniel (n = 17), were studied. The dogs were classified into three groups: lean, overweight and obese, according to the 5-point Body Condition Score (BCS) scale. In the cohort of Labradors a complete phenotypic data (age, sex, neutering status, body weight and BCS) were collected for 127 dogs. The entire coding sequence as well as 5' and 3'-flanking regions of the studied gene were sequenced and six polymorphic sites were reported. Genotype frequencies differed considerably between breeds and Labrador Retrievers appeared to be the less polymorphic. Moreover, distribution of some polymorphic variants differed significantly (P C, c.868C>T and c.*33C>G) and Beagles (c.-435T>C and c.637G>T). On the contrary, in Labradors no association between the studied polymorphisms and BCS or body weight was observed. Methylation analysis, using bisulfite DNA conversion followed by Sanger sequencing, was carried out for 12 dogs with BCS = 3 and 12 dogs with BCS = 5. Two intragenic CpG islands, containing 19 cytosines, were analyzed and the methylation profile did not differ significantly between lean and obese animals. We conclude that an association of the MC4R gene polymorphism with dog obesity or body weight is unlikely, in spite of the fact that some associations were found in small cohorts of Beagles and Golden Retrievers. Also methylation level of this gene is not related with dog adiposity.

A Val85Met Mutation in Melanocortin-1 Receptor Is Associated with Reductions in Eumelanic Pigmentation and Cell Surface Expression in Domestic Rock Pigeons (Columba livia)

Science.gov (United States)

Guernsey, Michael W.; Ritscher, Lars; Miller, Matthew A.; Smith, Daniel A.; Schöneberg, Torsten; Shapiro, Michael D.

2013-01-01

Variation in the melanocortin-1 receptor (Mc1r) is associated with pigmentation diversity in wild and domesticated populations of vertebrates, including several species of birds. Among domestic bird species, pigmentation variation in the rock pigeon ( Columba livia ) is particularly diverse. To determine the potential contribution of Mc1r variants to pigment diversity in pigeons, we sequenced Mc1r in a wide range of pigeon breeds and identified several single nucleotide polymorphisms, including a variant that codes for an amino acid substitution (Val85Met). In contrast to the association between Val85Met and eumelanism in other avian species, this change was associated with pheomelanism in pigeons. In vitro cAMP accumulation and protein expression assays revealed that Val85Met leads to decreased receptor function and reduced cell surface expression of the mutant protein. The reduced in vitro function is consistent with the observed association with reduced eumelanic pigmentation. Comparative genetic and cellular studies provide important insights about the range of mechanisms underlying diversity among vertebrates, including different phenotypic associations with similar mutations in different species. PMID:23977400

Identification of candidate genes for dyslexia susceptibility on chromosome 18.

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Thomas S Scerri

2010-10-01

Full Text Available Six independent studies have identified linkage to chromosome 18 for developmental dyslexia or general reading ability. Until now, no candidate genes have been identified to explain this linkage. Here, we set out to identify the gene(s conferring susceptibility by a two stage strategy of linkage and association analysis.Linkage analysis: 264 UK families and 155 US families each containing at least one child diagnosed with dyslexia were genotyped with a dense set of microsatellite markers on chromosome 18. Association analysis: Using a discovery sample of 187 UK families, nearly 3000 SNPs were genotyped across the chromosome 18 dyslexia susceptibility candidate region. Following association analysis, the top ranking SNPs were then genotyped in the remaining samples. The linkage analysis revealed a broad signal that spans approximately 40 Mb from 18p11.2 to 18q12.2. Following the association analysis and subsequent replication attempts, we observed consistent association with the same SNPs in three genes; melanocortin 5 receptor (MC5R, dymeclin (DYM and neural precursor cell expressed, developmentally down-regulated 4-like (NEDD4L.Along with already published biological evidence, MC5R, DYM and NEDD4L make attractive candidates for dyslexia susceptibility genes. However, further replication and functional studies are still required.

Genetic subspecies diversity of the chimpanzee CD4 virus-receptor gene

DEFF Research Database (Denmark)

Hvilsom, Christina; Carlsen, Frands; Siegismund, Hans R

2008-01-01

six among the subspecies of chimpanzees. We found the CD4 receptor to be conserved in individuals belonging to the P. t. verus subspecies and divergent from the other three subspecies, which harbored highly variable CD4 receptors. The CD4 receptor of chimpanzees differed from that of humans. We...... question whether the observed diversity can explain the species-specific differences in susceptibility to and pathogenicity of SIV/HIV....

Melanocortin-1 receptor, skin cancer and phenotypic characteristics (M-SKIP project: study design and methods for pooling results of genetic epidemiological studies

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Raimondi Sara

2012-08-01

Full Text Available Abstract Background For complex diseases like cancer, pooled-analysis of individual data represents a powerful tool to investigate the joint contribution of genetic, phenotypic and environmental factors to the development of a disease. Pooled-analysis of epidemiological studies has many advantages over meta-analysis, and preliminary results may be obtained faster and with lower costs than with prospective consortia. Design and methods Based on our experience with the study design of the Melanocortin-1 receptor (MC1R gene, SKin cancer and Phenotypic characteristics (M-SKIP project, we describe the most important steps in planning and conducting a pooled-analysis of genetic epidemiological studies. We then present the statistical analysis plan that we are going to apply, giving particular attention to methods of analysis recently proposed to account for between-study heterogeneity and to explore the joint contribution of genetic, phenotypic and environmental factors in the development of a disease. Within the M-SKIP project, data on 10,959 skin cancer cases and 14,785 controls from 31 international investigators were checked for quality and recoded for standardization. We first proposed to fit the aggregated data with random-effects logistic regression models. However, for the M-SKIP project, a two-stage analysis will be preferred to overcome the problem regarding the availability of different study covariates. The joint contribution of MC1R variants and phenotypic characteristics to skin cancer development will be studied via logic regression modeling. Discussion Methodological guidelines to correctly design and conduct pooled-analyses are needed to facilitate application of such methods, thus providing a better summary of the actual findings on specific fields.

Melanocortin-1 receptor, skin cancer and phenotypic characteristics (M-SKIP) project: study design and methods for pooling results of genetic epidemiological studies

Science.gov (United States)

2012-01-01

Background For complex diseases like cancer, pooled-analysis of individual data represents a powerful tool to investigate the joint contribution of genetic, phenotypic and environmental factors to the development of a disease. Pooled-analysis of epidemiological studies has many advantages over meta-analysis, and preliminary results may be obtained faster and with lower costs than with prospective consortia. Design and methods Based on our experience with the study design of the Melanocortin-1 receptor (MC1R) gene, SKin cancer and Phenotypic characteristics (M-SKIP) project, we describe the most important steps in planning and conducting a pooled-analysis of genetic epidemiological studies. We then present the statistical analysis plan that we are going to apply, giving particular attention to methods of analysis recently proposed to account for between-study heterogeneity and to explore the joint contribution of genetic, phenotypic and environmental factors in the development of a disease. Within the M-SKIP project, data on 10,959 skin cancer cases and 14,785 controls from 31 international investigators were checked for quality and recoded for standardization. We first proposed to fit the aggregated data with random-effects logistic regression models. However, for the M-SKIP project, a two-stage analysis will be preferred to overcome the problem regarding the availability of different study covariates. The joint contribution of MC1R variants and phenotypic characteristics to skin cancer development will be studied via logic regression modeling. Discussion Methodological guidelines to correctly design and conduct pooled-analyses are needed to facilitate application of such methods, thus providing a better summary of the actual findings on specific fields. PMID:22862891

Missense and nonsense mutations in melanocortin 1 receptor (MC1R gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences

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Davoli Roberta

2009-08-01

Full Text Available Abstract Background Agouti and Extension loci control the relative amount of eumelanin and pheomelanin production in melanocytes that, in turn, affects pigmentation of skin and hair. The Extension locus encodes the melanocortin 1 receptor (MC1R whose permanent activation, caused by functional mutations, results in black coat colour, whereas other inactivating mutations cause red coat colour in different mammals. Results The whole coding region of the MC1R gene was sequenced in goats of six different breeds showing different coat colours (Girgentana, white cream with usually small red spots in the face; Maltese, white with black cheeks and ears; Derivata di Siria, solid red; Murciano-Granadina, solid black or solid brown; Camosciata delle Alpi, brown with black stripes; Saanen, white; F1 goats and the parental animals. Five single nucleotide polymorphisms (SNPs were identified: one nonsense mutation (p.Q225X, three missense mutations (p.A81V, p.F250V, and p.C267W, and one silent mutation. The stop codon at position 225 should cause the production of a shorter MC1R protein whose functionality may be altered. These SNPs were investigated in a larger sample of animals belonging to the six breeds. The Girgentana breed was almost fixed for the p.225X allele. However, there was not complete association between the presence of red spots in the face and the presence of this allele in homozygous condition. The same allele was identified in the Derivata di Siria breed. However, its frequency was only 33%, despite the fact that these animals are completely red. The p.267W allele was present in all Murciano-Granadina black goats, whereas it was never identified in the brown ones. Moreover, the same substitution was present in almost all Maltese goats providing evidence of association between this mutation and black coat colour. Conclusion According to the results obtained in the investigated goat breeds, MC1R mutations may determine eumelanic and pheomelanic

The Mouse Solitary Odorant Receptor Gene Promoters as Models for the Study of Odorant Receptor Gene Choice.

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Andrea Degl'Innocenti

Full Text Available In vertebrates, several anatomical regions located within the nasal cavity mediate olfaction. Among these, the main olfactory epithelium detects most conventional odorants. Olfactory sensory neurons, provided with cilia exposed to the air, detect volatile chemicals via an extremely large family of seven-transmembrane chemoreceptors named odorant receptors. Their genes are expressed in a monogenic and monoallelic fashion: a single allele of a single odorant receptor gene is transcribed in a given mature neuron, through a still uncharacterized molecular mechanism known as odorant receptor gene choice.Odorant receptor genes are typically arranged in genomic clusters, but a few are isolated (we call them solitary from the others within a region broader than 1 Mb upstream and downstream with respect to their transcript's coordinates. The study of clustered genes is problematic, because of redundancy and ambiguities in their regulatory elements: we propose to use the solitary genes as simplified models to understand odorant receptor gene choice.Here we define number and identity of the solitary genes in the mouse genome (C57BL/6J, and assess the conservation of the solitary status in some mammalian orthologs. Furthermore, we locate their putative promoters, predict their homeodomain binding sites (commonly present in the promoters of odorant receptor genes and compare candidate promoter sequences with those of wild-caught mice. We also provide expression data from histological sections.In the mouse genome there are eight intact solitary genes: Olfr19 (M12, Olfr49, Olfr266, Olfr267, Olfr370, Olfr371, Olfr466, Olfr1402; five are conserved as solitary in rat. These genes are all expressed in the main olfactory epithelium of three-day-old mice. The C57BL/6J candidate promoter of Olfr370 has considerably varied compared to its wild-type counterpart. Within the putative promoter for Olfr266 a homeodomain binding site is predicted. As a whole, our findings

A novel role for pigment genes in the stress response in rainbow trout (Oncorhynchus mykiss)

KAUST Repository

Khan, Uniza Wahid

2016-07-04

In many vertebrate species visible melanin-based pigmentation patterns correlate with high stress- and disease-resistance, but proximate mechanisms for this trait association remain enigmatic. Here we show that a missense mutation in a classical pigmentation gene, melanocyte stimulating hormone receptor (MC1R), is strongly associated with distinct differences in steroidogenic melanocortin 2 receptor (MC2R) mRNA expression between high- (HR) and low-responsive (LR) rainbow trout (Oncorhynchus mykiss). We also show experimentally that cortisol implants increase the expression of agouti signaling protein (ASIP) mRNA in skin, likely explaining the association between HR-traits and reduced skin melanin patterning. Molecular dynamics simulations predict that melanocortin 2 receptor accessory protein (MRAP), needed for MC2R function, binds differently to the two MC1R variants. Considering that mRNA for MC2R and the MC1R variants are present in head kidney cells, we hypothesized that MC2R activity is modulated in part by different binding affinities of the MC1R variants for MRAP. Experiments in mammalian cells confirmed that trout MRAP interacts with the two trout MC1R variants and MC2R, but failed to detect regulation of MC2R signaling, possibly due to high constitutive MC1R activity.

Seven transmembrane G protein-coupled receptor repertoire of gastric ghrelin cells

DEFF Research Database (Denmark)

Engelstoft, Maja S; Park, Won-Mee; Sakata, Ichiro

2013-01-01

The molecular mechanisms regulating secretion of the orexigenic-glucoregulatory hormone ghrelin remain unclear. Based on qPCR analysis of FACS-purified gastric ghrelin cells, highly expressed and enriched 7TM receptors were comprehensively identified and functionally characterized using in vitro......, ex vivo and in vivo methods. Five Gαs-coupled receptors efficiently stimulated ghrelin secretion: as expected the β1-adrenergic, the GIP and the secretin receptors but surprisingly also the composite receptor for the sensory neuropeptide CGRP and the melanocortin 4 receptor. A number of Gαi....../o-coupled receptors inhibited ghrelin secretion including somatostatin receptors SSTR1, SSTR2 and SSTR3 and unexpectedly the highly enriched lactate receptor, GPR81. Three other metabolite receptors known to be both Gαi/o- and Gαq/11-coupled all inhibited ghrelin secretion through a pertussis toxin-sensitive Gαi...

Hypertension-Related Gene Polymorphisms of G-Protein-Coupled Receptor Kinase 4 Are Associated with NT-proBNP Concentration in Normotensive Healthy Adults

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Junichi Yatabe

2012-01-01

Full Text Available G protein-coupled receptor kinase 4 (GRK4 with activating polymorphisms desensitize the natriuric renal tubular D1 dopamine receptor, and these GRK4 polymorphisms are strongly associated with salt sensitivity and hypertension. Meanwhile, N-terminal pro-B-type natriuretic peptide (NT-proBNP may be useful in detecting slight volume expansion. However, relations between hypertension-related gene polymorphisms including GRK4 and cardiovascular indices such as NT-proBNP are not clear, especially in healthy subjects. Therefore, various hypertension-related polymorphisms and cardiovascular indices were analyzed in 97 normotensive, healthy Japanese adults. NT-proBNP levels were significantly higher in subjects with two or more GRK4 polymorphic alleles. Other hypertension-related gene polymorphisms, such as those of renin-angiotensin-aldosterone system genes, did not correlate with NT-proBNP. There was no significant association between any of the hypertension-related gene polymorphisms and central systolic blood pressure, cardioankle vascular index, augmentation index, plasma aldosterone concentration, or an oxidative stress marker, urinary 8-OHdG. Normotensive individuals with GRK4 polymorphisms show increased serum NT-proBNP concentration and may be at a greater risk of developing hypertension and cardiovascular disease.

A high-throughput fluorescence-based assay system for appetite-regulating gene and drug screening.

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Yasuhito Shimada

Full Text Available The increasing number of people suffering from metabolic syndrome and obesity is becoming a serious problem not only in developed countries, but also in developing countries. However, there are few agents currently approved for the treatment of obesity. Those that are available are mainly appetite suppressants and gastrointestinal fat blockers. We have developed a simple and rapid method for the measurement of the feeding volume of Danio rerio (zebrafish. This assay can be used to screen appetite suppressants and enhancers. In this study, zebrafish were fed viable paramecia that were fluorescently-labeled, and feeding volume was measured using a 96-well microplate reader. Gene expression analysis of brain-derived neurotrophic factor (bdnf, knockdown of appetite-regulating genes (neuropeptide Y, preproinsulin, melanocortin 4 receptor, agouti related protein, and cannabinoid receptor 1, and the administration of clinical appetite suppressants (fluoxetine, sibutramine, mazindol, phentermine, and rimonabant revealed the similarity among mechanisms regulating appetite in zebrafish and mammals. In combination with behavioral analysis, we were able to evaluate adverse effects on locomotor activities from gene knockdown and chemical treatments. In conclusion, we have developed an assay that uses zebrafish, which can be applied to high-throughput screening and target gene discovery for appetite suppressants and enhancers.

Association between genetic variants and obesity in the Lithuanian adult population

OpenAIRE

Smalinskienė, Alina; Petkevičienė, Janina; Klumbienė, Jūratė; Lesauskaitė, Vaiva

2018-01-01

Introduction: Eating habits play a big role in the onset of obesity and there are some genes, associated with regulation of the food intake. The melanocortin-4 receptor (MC4R) and neuropeptide Y (NPY) are peptides that play part in the hypothalamic appetite regulation mechanism. Fat mass and obesity associated (FTO) gene variant is associated with human adiposity and metabolic disorders. The aim of this study was to evaluate the effect of MC4R, NPY and FTO genes polymorphisms on body mass ind...

Nuclear receptor 4A (NR4A) family - orphans no more.

Science.gov (United States)

Safe, Stephen; Jin, Un-Ho; Morpurgo, Benjamin; Abudayyeh, Ala; Singh, Mandip; Tjalkens, Ronald B

2016-03-01

The orphan nuclear receptors NR4A1, NR4A2 and NR4A3 are immediate early genes induced by multiple stressors, and the NR4A receptors play an important role in maintaining cellular homeostasis and disease. There is increasing evidence for the role of these receptors in metabolic, cardiovascular and neurological functions and also in inflammation and inflammatory diseases and in immune functions and cancer. Despite the similarities of NR4A1, NR4A2 and NR4A3 and their interactions with common cis-genomic elements, they exhibit unique activities and cell-/tissue-specific functions. Although endogenous ligands for NR4A receptors have not been identified, there is increasing evidence that structurally-diverse synthetic molecules can directly interact with the ligand binding domain of NR4A1 and act as agonists or antagonists, and ligands for NR4A2 and NR4A3 have also been identified. Since NR4A receptors are key factors in multiple diseases, there are opportunities for the future development of NR4A ligands for clinical applications in treating multiple health problems including metabolic, neurologic and cardiovascular diseases, other inflammatory conditions, and cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prevalence of mutations and functional analyses of melanocortin 4 receptor variants identified among 750 men with juvenile-onset obesity

DEFF Research Database (Denmark)

Larsen, Lesli H; Echwald, Søren Morgenthaler; Sørensen, Thorkild I A

2005-01-01

)) for mutations in MC4R. A total of 14 different mutations were identified of which two, Ala219Val and Leu325Phe, were novel variants. The variant receptor, Leu325Phe, was unable to bind [Nle4,d-Phe7]-alphaMSH, whereas the Ala219Val variant showed a significantly impaired melanotan II induction of cAMP, compared...

alpha-MSH and its receptors in regulation of tumor necrosis factor-alpha production by human monocyte/macrophages.

Science.gov (United States)

Taherzadeh, S; Sharma, S; Chhajlani, V; Gantz, I; Rajora, N; Demitri, M T; Kelly, L; Zhao, H; Ichiyama, T; Catania, A; Lipton, J M

1999-05-01

The hypothesis that macrophages contain an autocrine circuit based on melanocortin [ACTH and alpha-melanocyte-stimulating hormone (alpha-MSH)] peptides has major implications for neuroimmunomodulation research and inflammation therapy. To test this hypothesis, cells of the THP-1 human monocyte/macrophage line were stimulated with lipopolysaccharide (LPS) in the presence and absence of alpha-MSH. The inflammatory cytokine tumor necrosis factor (TNF)-alpha was inhibited in relation to alpha-MSH concentration. Similar inhibitory effects on TNF-alpha were observed with ACTH peptides that contain the alpha-MSH amino acid sequence and act on melanocortin receptors. Nuclease protection assays indicated that expression of the human melanocortin-1 receptor subtype (hMC-1R) occurs in THP-1 cells; Southern blots of RT-PCR product revealed that additional subtypes, hMC-3R and hMC-5R, also occur. Incubation of resting macrophages with antibody to hMC-1R increased TNF-alpha concentration; the antibody also markedly reduced the inhibitory influence of alpha-MSH on TNF-alpha in macrophages treated with LPS. These results in cells known to produce alpha-MSH at rest and to increase secretion of the peptide when challenged are consistent with an endogenous regulatory circuit based on melanocortin peptides and their receptors. Targeting of this neuroimmunomodulatory circuit in inflammatory diseases in which myelomonocytic cells are prominent should be beneficial.

Identification of the interleukin 4 receptor alpha gene as a direct target for p73.

Science.gov (United States)

Sasaki, Yasushi; Mita, Hiroaki; Toyota, Minoru; Ishida, Setsuko; Morimoto, Ichiro; Yamashita, Toshiharu; Tanaka, Toshihiro; Imai, Kohzoh; Nakamura, Yusuke; Tokino, Takashi

2003-12-01

p73 has a high degree of structural homology to p53 and can activate transcription of p53-responsive genes. However, analysis of p73-deficient mice revealed a marked divergence in the physiological activities of p53 family genes and distinguishes p73 from p53. Mice deficient for p73 exhibit profound defects, including hippocampal dysgenesis, chronic infection, and inflammation, as well as abnormalities in pheromone sensory pathways. p73 plays important roles in neurogenesis, sensory pathways, and homeostatic regulation. Here, we found that the interleukin 4 receptor alpha (IL-4Ralpha) gene is up-regulated by p73 but not significantly by p53 in several human cancer cell lines. IL-4Ralphatranscription is also activated in response to cisplatin, a DNA-damaging agent known to induce p73. By using small interference RNA designed to target p73, we demonstrated that silencing endogenous p73 abrogates the induction of the IL-4Ralpha gene after cisplatin treatment. Furthermore, we identified a p73-binding site in the first intron of the IL-4Ralpha gene that can directly interact with the p73 protein in vivo. This p73-binding site consists of eight copies of a 10-bp consensus p53-binding motif and is a functional response element that is relatively specific for p73 among the p53 family. p73beta promoted localized nucleosomal acetylation through recruitment of coactivator p300, indicating that p73 regulates transcription of IL-4Ralpha through the unique p73-binding site. We also found that p73beta-transfected tumor cells are sensitive to IL-4-mediated apoptosis. Our data suggest that IL-4Ralpha could mediate, in part, certain immune responses and p73-dependent cell death.

Association between MC4R rs17782313 polymorphism and overeating behaviors.

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Yilmaz, Z; Davis, C; Loxton, N J; Kaplan, A S; Levitan, R D; Carter, J C; Kennedy, J L

2015-01-01

Melanocortins have a crucial role in appetite and weight regulation. Although the melanocortin 4 receptor (MC4R) gene has been repeatedly linked to obesity and antipsychotic-induced weight gain, the mechanism behind how it leads to this effect in still undetermined. The goal of this study was to conduct an in-depth and sophisticated analysis of MC4R polymorphisms, body mass index (BMI), eating behavior and depressed mood. We genotyped 328 individuals of European ancestry on the following MC4R markers based on the relevant literature on obesity and antipsychotic-induced weight gain: rs571312, rs17782313, rs489693, rs11872992, and rs8087522. Height and weight were measured, and information on depressed mood and overeating behaviors was obtained during the in-person assessment. BMI was associated with rs17782313 C allele; however, this finding did not survive correction for multiple testing (P = 0.018). Although rs17782313 was significantly associated with depressed mood and overeating behaviors, tests of indirect effects indicated that emotional eating and food cravings, rather than depressed mood, uniquely accounted for the effect of this marker and BMI (n = 152). To our knowledge, this is the first study to investigate the link between MC4R rs17782313, mood and overeating behavior, as well as to demonstrate possible mechanisms behind MC4R's influence on body weight. If replicated in a larger sample, these results may have important clinical implications, including potential for the use of MC4R agonists in the treatment of obesity and disordered eating.

Characterization and functional analyses of the human G protein-coupled receptor kinase 4 gene promoter.

Science.gov (United States)

Hasenkamp, Sandra; Telgmann, Ralph; Staessen, Jan A; Hagedorn, Claudia; Dördelmann, Corinna; Bek, Martin; Brand-Herrmann, Stefan-Martin; Brand, Eva

2008-10-01

The G protein-coupled receptor kinase 4 is involved in renal sodium handling and blood pressure regulation. Missense variants have already been tested functionally and are associated with hypertension, but no data on promoter analyses are yet available. We scanned 94 hypertensive white subjects for genetic variation and performed promoter reporter gene analyses in HEK293T, COS7, and SaOs-2 cells. Transient transfections with various full lengths and wild-type deletion constructs revealed that 1851 bp of the flanking region and 275 bp of the 5'-untranslated region were sufficient for transcriptional activities and composed a powerful cis-active element in the distal 293 bp. The -1702T and +2T alleles resulted in drastic general reductions of promoter function, whereas an activity increasing effect of +268C was cell type specific. Electrophoretic mobility-shift assay, supershift, and cotransfection analyses of transcription factor binding sites predicted in silico (Alibaba2.1/Transfac7) resulted in allele-specific binding patterns of nuclear proteins and identified the participation of CCAAT/enhancer-binding protein transcription factor family members. The G protein-coupled receptor kinase 4 core promoter resides in the first 1851 bp upstream of its transcription start site. The 4 identified genetic variants within this region exert allele-specific impact on both cell type- and stimulation-dependent transcription and may affect the expression balance of renal G protein-coupled receptor kinase 4.

Genetic characterization of the chemokine receptor CXCR4 gene in lagomorphs: comparison between the families Ochotonidae and Leporidae.

Science.gov (United States)

Abrantes, J; Esteves, P J; Carmo, C R; Müller, A; Thompson, G; van der Loo, W

2008-04-01

Chemokines receptors are transmembrane proteins that bind chemokines. Chemokines and their receptors are known to play a crucial role in the immune system and in pathogen entry. There is evidence that myxoma virus, the causative agent of myxomatosis, can use the chemokine receptor CXCR4 to infect cells. This virus causes a benign disease in its natural host, Sylvilagus, but in the European rabbit (Oryctolagus cuniculus) it causes a highly fatal and infectious disease known as myxomatosis. We have characterized the chemokine receptor CXCR4 gene in five genera of the order Lagomorpha, Ochotona (Ochotonidae), and Oryctolagus, Lepus, Bunolagus and Sylvilagus (Leporidae). In lagomorphs, the CXCR4 is highly conserved, with most of the protein diversity found at surface regions. Five amino acid replacements were observed, two in the intracellular loops, one in the transmembrane domain and two in the extracellular loops. Oryctolagus features unique amino acid changes at the intracellular domains, putting this genus apart of all other lagomorphs. Furthermore, in the 37 European rabbits analysed, which included healthy rabbits and rabbits with clinical symptoms of myxomatosis, 14 nucleotide substitutions were obtained but no amino acid differences were observed.

Polymorphisms in the vitamin D receptor gene and the androgen receptor gene and the risk of benign prostatic hyperplasia

NARCIS (Netherlands)

Bousema, J. T.; Bussemakers, M. J.; van Houwelingen, K. P.; Debruyne, F. M.; Verbeek, A. L.; de la Rosette, J. J.; Kiemeney, L. A.

2000-01-01

Little is known about risk factors for the development of benign prostatic hyperplasia (BPH). Recently, associations were observed between prostate cancer (CaP) risk and polymorphisms in the vitamin D receptor (VDR) gene and the androgen receptor (AR) gene. Since both receptors are relevant for

Evidence that multiple genetic variants of MC4R play a functional role in the regulation of energy expenditure and appetite in Hispanic children

Science.gov (United States)

Melanocortin-4-receptor (MC4R) haploinsufficiency is the most common form of monogenic obesity; however, the frequency of MC4R variants and their functional effects in general populations remain uncertain. The aim of this study was to identify and characterize the effects of MC4R variants in Hispani...

Melanocortin 4 receptor is not required for estrogenic regulations on energy homeostasis and reproduction

Science.gov (United States)

Brain estrogen receptor-a (ERa) is essential for estrogenic regulation of energy homeostasis and reproduction. We previously showed that ERa expressed by pro-opiomelanocortin (POMC) neurons mediates estrogen's effects on food intake, body weight, negative regulation of hypothalamic–pituitary–gonadal...

Pharmacological characterization of canine melancortin-4 receptor and its natural variant V213F.

Science.gov (United States)

Yan, J; Tao, Y-X

2011-08-01

Dogs have become one of the most important companion animals in modern society. However, it is estimated that 20% to 40% of owned dogs are obese, suggesting that obesity has become one of the most important canine health problem. In addition, obesity in dogs also leads to type II diabetes. Because the melanocortin-4 receptor (MC4R) has been shown to be essential in maintaining energy homeostasis in several different species, including rodents and humans, we initiated studies toward elucidating the roles of MC4R in obesity pathogenesis in dogs. Canine MC4R has been cloned, and a missense variant V213F was identified. We designed primers and successfully cloned canine MC4R and generated the variant V213F by site-directed mutagenesis. The objective of this study was to investigate the pharmacological properties of canine MC4R and its natural variant V213F. We measured ligand binding and signaling properties with the use of both natural and synthetic ligands. Human MC4R was also included in the experiments for comparison. Both wild-type canine MC4R and its natural variant V213F functioned normally in terms of binding and signaling. Of the ligands we used, [Nle(4), D-Phe(7)]-α-melanocyte-stimulating hormone is the most potent ligand. We conclude that the cloned canine MC4R is a functional receptor, and the natural variant V213F does not have any functional defect and therefore is not likely to cause obesity in dogs. Copyright © 2011 Elsevier Inc. All rights reserved.

Chromosomal organization of adrenergic receptor genes

International Nuclear Information System (INIS)

Yang-Feng, T.L.; Xue, Feiyu; Zhong, Wuwei; Cotecchia, S.; Frielle, T.; Caron, M.G.; Lefkowitz, R.J.; Francke, U.

1990-01-01

The adrenergic receptors (ARs) (subtypes α 1 , α 2 , β 1 , and β 2 ) are a prototypic family of guanine nucleotide binding regulatory protein-coupled receptors that mediate the physiological effects of the hormone epinephrine and the neurotransmitter norepinephrine. The authors have previously assigned the genes for β 2 -and α 2 -AR to human chromosomes 5 and 10, respectively. By Southern analysis of somatic cell hybrids and in situ chromosomal hybridization, they have now mapped the α 1 -AR gene to chromosome 5q32→q34, the same position as β 2 -AR, and the β 1 -AR gene to chromosome 10q24→q26, the region where α 2 -AR, is located. In mouse, both α 2 -and β 1 -AR genes were assigned to chromosome 19, and the α 1 -AR locus was localized to chromosome 11. Pulsed field gel electrophoresis has shown that the α 1 -and β 2 -AR genes in humans are within 300 kilobases (kb) and the distance between the α 2 - and β 1 -AR genes is <225 kb. The proximity of these two pairs of AR genes and the sequence similarity that exists among all the ARs strongly suggest that they are evolutionarily related. Moreover, they likely arose from a common ancestral receptor gene and subsequently diverged through gene duplication and chromosomal duplication to perform their distinctive roles in mediation the physiological effects of catecholamines. The AR genes thus provide a paradigm for understanding the evolution of such structurally conserved yet functionally divergent families off receptor molecules

Early vertebrate chromosome duplications and the evolution of the neuropeptide Y receptor gene regions

Directory of Open Access Journals (Sweden)

Brenner Sydney

2008-06-01

Full Text Available Abstract Background One of the many gene families that expanded in early vertebrate evolution is the neuropeptide (NPY receptor family of G-protein coupled receptors. Earlier work by our lab suggested that several of the NPY receptor genes found in extant vertebrates resulted from two genome duplications before the origin of jawed vertebrates (gnathostomes and one additional genome duplication in the actinopterygian lineage, based on their location on chromosomes sharing several gene families. In this study we have investigated, in five vertebrate genomes, 45 gene families with members close to the NPY receptor genes in the compact genomes of the teleost fishes Tetraodon nigroviridis and Takifugu rubripes. These correspond to Homo sapiens chromosomes 4, 5, 8 and 10. Results Chromosome regions with conserved synteny were identified and confirmed by phylogenetic analyses in H. sapiens, M. musculus, D. rerio, T. rubripes and T. nigroviridis. 26 gene families, including the NPY receptor genes, (plus 3 described recently by other labs showed a tree topology consistent with duplications in early vertebrate evolution and in the actinopterygian lineage, thereby supporting expansion through block duplications. Eight gene families had complications that precluded analysis (such as short sequence length or variable number of repeated domains and another eight families did not support block duplications (because the paralogs in these families seem to have originated in another time window than the proposed genome duplication events. RT-PCR carried out with several tissues in T. rubripes revealed that all five NPY receptors were expressed in the brain and subtypes Y2, Y4 and Y8 were also expressed in peripheral organs. Conclusion We conclude that the phylogenetic analyses and chromosomal locations of these gene families support duplications of large blocks of genes or even entire chromosomes. Thus, these results are consistent with two early vertebrate

α-4 subunit of nicotinic acetylcholine receptor polymorphisms exhibit ...

African Journals Online (AJOL)

Background: Smoking behavior is influenced by both genetic and environmental factors. Nicotine is the major addictive substance in cigarettes. Nicotinic acetylcholine receptors (nAChRs) are thought to play an important role in nicotine addiction of smokers. One of the genes, α-4 subunit of nicotinic acetylcholine receptor ...

Replicated Risk Nicotinic Cholinergic Receptor Genes for Nicotine Dependence

Directory of Open Access Journals (Sweden)

Lingjun Zuo

2016-11-01

Full Text Available It has been hypothesized that the nicotinic acetylcholine receptors (nAChRs play important roles in nicotine dependence (ND and influence the number of cigarettes smoked per day (CPD in smokers. We compiled the associations between nicotinic cholinergic receptor genes (CHRNs and ND/CPD that were replicated across different studies, reviewed the expression of these risk genes in human/mouse brains, and verified their expression using independent samples of both human and mouse brains. The potential functions of the replicated risk variants were examined using cis-eQTL analysis or predicted using a series of bioinformatics analyses. We found replicated and significant associations for ND/CPD at 19 SNPs in six genes in three genomic regions (CHRNB3-A6, CHRNA5-A3-B4 and CHRNA4. These six risk genes are expressed in at least 18 distinct areas of the human/mouse brain, with verification in our independent human and mouse brain samples. The risk variants might influence the transcription, expression and splicing of the risk genes, alter RNA secondary or protein structure. We conclude that the replicated associations between CHRNB3-A6, CHRNA5-A3-B4, CHRNA4 and ND/CPD are very robust. More research is needed to examine how these genetic variants contribute to the risk for ND/CPD.

Genomic evidence of gene duplication and adaptive evolution of Toll like receptors (TLR2 and TLR4) in reptiles.

Science.gov (United States)

Shang, Shuai; Zhong, Huaming; Wu, Xiaoyang; Wei, Qinguo; Zhang, Huanxin; Chen, Jun; Chen, Yao; Tang, Xuexi; Zhang, Honghai

2018-04-01

Toll-like receptors (TLRs) encoded by the TLR multigene family play an important role in initial pathogen recognition in vertebrates. Among the TLRs, TLR2 and TLR4 may be of particular importance to reptiles. In order to study the evolutionary patterns and structural characteristics of TLRs, we explored the available genomes of several representative members of reptiles. 25 TLR2 genes and 19 TLR4 genes from reptiles were obtained in this study. Phylogenetic results showed that the TLR2 gene duplication occurred in several species. Evolutionary analysis by at least two methods identified 30 and 13 common positively selected codons in TLR2 and TLR4, respectively. Most positively selected sites of TLR2 and TLR4 were located in the Leucine-rich repeat (LRRs). Branch model analysis showed that TLR2 genes were under different evolutionary forces in reptiles, while the TLR4 genes showed no significant selection pressure. The different evolutionary adaptation of TLR2 and TLR4 among the reptiles might be due to their different function in recognizing bacteria. Overall, we explored the structure and evolution of TLR2 and TLR4 genes in reptiles for the first time. Our study revealed valuable information regarding TLR2 and TLR4 in reptiles, and provided novel insights into the conservation concern of natural populations. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of Various Statistical Models to Explore Gene-Gene Interactions in Folate, Xenobiotic, Toll-Like Receptor and STAT4 Pathways that Modulate Susceptibility to Systemic Lupus Erythematosus.

Science.gov (United States)

Rupasree, Yedluri; Naushad, Shaik Mohammad; Varshaa, Ravi; Mahalakshmi, Govindaraj Swathika; Kumaraswami, Konda; Rajasekhar, Liza; Kutala, Vijay Kumar

2016-02-01

In view of our previous studies showing an independent association of genetic polymorphisms in folate, xenobiotic, and toll-like receptor (TLR) pathways with the risk for systemic lupus erythematosus (SLE), we have developed three statistical models to delineate complex gene-gene interactions between folate, xenobiotic, TLR, and signal transducer and activator of transcription 4 (STAT4) signaling pathways in association with the molecular pathophysiology of SLE. We developed additive, multifactor dimensionality reduction (MDR), and artificial neural network (ANN) models. The additive model, although the simplest, suggested a moderate predictability of 30 polymorphisms of these four pathways (area under the curve [AUC] 0.66). MDR analysis revealed significant gene-gene interactions among glutathione-S-transferase (GST)T1 and STAT4 (rs3821236 and rs7574865) polymorphisms, which account for moderate predictability of SLE. The MDR model for specific auto-antibodies revealed the importance of gene-gene interactions among cytochrome P450, family1, subfamily A, polypeptide 1 (CYP1A1) m1, catechol-O-methyltransferase (COMT) H108L, solute carrier family 19 (folate transporter), member 1 (SLC19A1) G80A, estrogen receptor 1 (ESR1), TLR5, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR), thymidylate synthase (TYMS). and STAT4 polymorphisms. The ANN model for disease prediction showed reasonably good predictability of SLE risk with 30 polymorphisms (AUC 0.76). These polymorphisms contribute towards the production of SSB and anti-dsDNA antibodies to the extent of 48 and 40%, respectively, while their contribution for the production of antiRNP, SSA, and anti-cardiolipin antibodies varies between 20 and 30%. The current study highlighted the importance of genetic polymorphisms in folate, xenobiotic, TLR, and STAT4 signaling pathways as moderate predictors of SLE risk and delineates the molecular pathophysiology associated with these single nucleotide

Variants in the dopamine-4-receptor gene promoter are not associated with sensation seeking in skiers.

Science.gov (United States)

Thomson, Cynthia J; Rajala, Amelia K; Carlson, Scott R; Rupert, Jim L

2014-01-01

Sensation seeking is a personality trait that has been associated with disinhibited behaviours including substance use and gambling, but also with high-risk sport practices including skydiving, paragliding, and downhill skiing. Twin studies have shown that sensation seeking is moderately heritable, and candidate genes encoding components involved in dopaminergic transmission have been investigated as contributing to this type of behaviour. To determine whether variants in the regulatory regions of the dopamine-4-receptor gene (DRD4) influenced sport-specific sensation seeking, we analyzed five polymorphisms (-1106T/C, -906T/C, -809G/A, -291C/T, 120-bp duplication) in the promoter region of the gene in a cohort of skiers and snowboarders (n = 599) that represented a broad range of sensation seeking behaviours. We grouped subjects by genotype at each of the five loci and compared impulsive sensation seeking and domain-specific (skiing) sensation seeking between groups. There were no significant associations between genotype(s) and general or domain-specific sensation seeking in the skiers and snowboarders, suggesting that while DRD4 has previously been implicated in sensation seeking, the promoter variants investigated in this study do not contribute to sensation seeking in this athlete population.

Sim1 Neurons Are Sufficient for MC4R-Mediated Sexual Function in Male Mice.

Science.gov (United States)

Semple, Erin; Hill, Jennifer W

2018-01-01

Sexual dysfunction is a poorly understood condition that affects up to one-third of men around the world. Existing treatments that target the periphery do not work for all men. Previous studies have shown that central melanocortins, which are released by pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus, can lead to male erection and increased libido. Several studies specifically implicate the melanocortin 4 receptor (MC4R) in the central control of sexual function, but the specific neural circuitry involved is unknown. We hypothesized that single-minded homolog 1 (Sim1) neurons play an important role in the melanocortin-mediated regulation of male sexual behavior. To test this hypothesis, we examined the sexual behavior of mice expressing MC4R only on Sim1-positive neurons (tbMC4Rsim1 mice) in comparison with tbMC4R null mice and wild-type controls. In tbMC4Rsim1 mice, MC4R reexpression was found in the medial amygdala and paraventricular nucleus of the hypothalamus. These mice were paired with sexually experienced females, and their sexual function and behavior was scored based on mounting, intromission, and ejaculation. tbMC4R null mice showed a longer latency to mount, a reduced intromission efficiency, and an inability to reach ejaculation. Expression of MC4R only on Sim1 neurons reversed the sexual deficits seen in tbMC4R null mice. This study implicates melanocortin signaling via the MC4R on Sim1 neurons in the central control of male sexual behavior. Copyright © 2018 Endocrine Society.

Aberrant expression of the tyrosine kinase receptor EphA4 and the transcription factor twist in Sézary syndrome identified by gene expression analysis.

Science.gov (United States)

van Doorn, Remco; Dijkman, Remco; Vermeer, Maarten H; Out-Luiting, Jacoba J; van der Raaij-Helmer, Elisabeth M H; Willemze, Rein; Tensen, Cornelis P

2004-08-15

Sézary syndrome (Sz) is a malignancy of CD4+ memory skin-homing T cells and presents with erythroderma, lymphadenopathy, and peripheral blood involvement. To gain more insight into the molecular features of Sz, oligonucleotide array analysis was performed comparing gene expression patterns of CD4+ T cells from peripheral blood of patients with Sz with those of patients with erythroderma secondary to dermatitis and healthy controls. Using unsupervised hierarchical clustering gene, expression patterns of T cells from patients with Sz were classified separately from those of benign T cells. One hundred twenty-three genes were identified as significantly differentially expressed and had an average fold change exceeding 2. T cells from patients with Sz demonstrated decreased expression of the following hematopoietic malignancy-linked tumor suppressor genes: TGF-beta receptor II, Mxi1, Riz1, CREB-binding protein, BCL11a, STAT4, and Forkhead Box O1A. Moreover, the tyrosine kinase receptor EphA4 and the potentially oncogenic transcription factor Twist were highly and selectively expressed in T cells of patients with Sz. High expression of EphA4 and Twist was also observed in lesional skin biopsy specimens of a subset of patients with cutaneous T cell lymphomas related to Sz, whereas their expression was nearly undetectable in benign T cells or in skin lesions of patients with inflammatory dermatoses. Detection of EphA4 and Twist may be used in the molecular diagnosis of Sz and related cutaneous T-cell lymphomas. Furthermore, the membrane-bound EphA4 receptor may serve as a target for directed therapeutic intervention.

Association of MC3R gene polymorphisms with body weight in the red fox and comparative gene organization in four canids.

Science.gov (United States)

Skorczyk, A; Flisikowski, K; Szydlowski, M; Cieslak, J; Fries, R; Switonski, M

2011-02-01

There are five genes encoding melanocortin receptors. Among canids, the genes have mainly been studied in the dog (MC1R, MC2R and MC4R). The MC4R gene has also been analysed in the red fox. In this report, we present a study of chromosome localization, comparative sequence analysis and polymorphism of the MC3R gene in the dog, red fox, arctic fox and Chinese raccoon dog. The gene was localized by FISH to the following chromosome: 24q24-25 in the dog, 14p16 in the red fox, 18q13 in the arctic fox and NPP4p15 in the Chinese raccoon dog. A high identity level of the MC3R gene sequences was observed among the species, ranging from 96.0% (red fox--Chinese raccoon dog) to 99.5% (red fox--arctic fox). Altogether, eight polymorphic sites were found in the red fox, six in the Chinese raccoon dog and two in the dog, while the arctic fox appeared to be monomorphic. In addition, association of several polymorphisms with body weight was analysed in red foxes (the number of genotyped animals ranged from 319 to 379). Two polymorphisms in the red fox, i.e. a silent substitution c.957A>C and c.*185C>T in the 3'-flanking sequence, showed a significant association (P < 0.01) with body weight. © 2010 The Authors, Animal Genetics © 2010 Stichting International Foundation for Animal Genetics.

Toll-like receptor 2 and 4 genes influence susceptibility to adverse effects of traffic-related air pollution on childhood asthma

NARCIS (Netherlands)

Kerkhof, M.; Postma, D. S.; Brunekreef, B.; Reijmerink, N. E.; Wijga, A. H.; de Jongste, J. C.; Gehring, U.; Koppelman, G. H.

Background Epidemiological studies have reported adverse effects of ambient air pollution on the prevalence of asthma. Laboratory studies have suggested that innate immune responses are involved. Objective A study was undertaken to determine whether the Toll-like receptor 2 and 4 genes (TLR2 and

Coamplification in tumors of KRAS2, type 2 inositol 1,4,5 triphosphate receptor gene, and a novel human gene, KRAG

Energy Technology Data Exchange (ETDEWEB)

Heighway, J.; Betticher, D.C.; Altermatt, H.J. [Univ. Hospital of Berne (Switzerland)] [and others

1996-07-01

Analysis of a region of DNA, coamplified in tumors with KRAS2, resulted in the identification of the human homologue of the mouse KRAG gene. The gene was widely expressed in range of cell lines, tumors, and normal tissue and demonstrated a high degree of alternate splicing. A human KRAG cDNA sequence, with a structure similar to that encoded by the amplified gene in mouse Y1 adrenal carcinoma cells, was isolated by RT-PCR. The predicted amino acid similarity between the two sequences was 91%, and hydrophobicity plots suggested a structure closely resembling that of transmembrane 4 superfamily members. Identification of a PCR-based restriction fragment length polymorphism allele-specific splicing differences in tumors. Northern analysis of mRNA derived from a range of tissues suggested high level expression in muscle and confirmed alternate splicing. To facilitate the analysis of exon junctions, a YAC clone encoding the genomic sequence was identified. This allowed the localization of KRAG to human chromosome 12p11.2. Isolation of one end of this nonchimeric clone demonstrated a perfect match with a 247-bp sequence within the 3{prime} untranslated region of the type 2 1,4,5-inositol triphosphate receptor gene. Multiplex PCR confirmed the inclusion of both genes. Multiplex PCR confirmed the inclusion of both genes in the KRAS2 amplicon in human malignancy, suggesting that either may contribute to the malignant phenotypes. 35 refs., 6 figs., 1 tab.

Research progress of the bitter taste receptor genes in primates.

Science.gov (United States)

Feng, Ping; Luo, Rui-Jian

2018-02-20

Among the five basic tastes (umami, sweet, bitter, salty and sour), the perception of bitterness is believed to protect animals from digesting toxic and harmful substances, thus it is vital for animal survival. The taste of bitterness is triggered by the interaction between bitter substances and bitter taste receptors, which are encoded by Tas2rs. The gene numbers vary largely across species to meet different demands. So far, several ligands of bitter receptors have been identified in primates. They also discovered that the selective pressure of certain bitter taste receptor genes vary across taxa, genes or even different functional regions of the gene. In this review, we summarize the research progress of bitter taste receptor genes in primates by introducing the functional diversity of bitter receptors, the specific interaction between bitter taste receptors and ligands, the relationship between the evolutionary pattern of bitter taste receptors and diets, and the adaptive evolution of bitter taste receptor genes. We aim to provide a reference for further research on bitter receptor genes in primates.

Genetic variability of aryl hydrocarbon receptor (AhR)-mediated regulation of the human UDP glucuronosyltransferase (UGT) 1A4 gene

Energy Technology Data Exchange (ETDEWEB)

Erichsen, Thomas J; Ehmer, Ursula; Kalthoff, Sandra; Lankisch, Tim O; Mueller, Tordis M [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany); Munzel, Peter A [Department of Toxicology, Institute of Pharmacology and Toxicology, University of Tubingen, Tubingen (Germany); Manns, Michael P [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany); Strassburg, Christian P. [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany)], E-mail: strassburg.christian@mh-hannover.de

2008-07-15

UDP glucuronosyltransferases (UGTs) play an important role for drug detoxification and toxicity. UGT function is genetically modulated by single nucleotide polymorphisms (SNPs) which lead to the expression of functionally altered protein, or altered expression levels. UGT1A4 activity includes anticonvulsants, antidepressants and environmental mutagens. In this study the induction of the human UGT1A4 gene and a potential influence of genetic variation in its promoter region were analyzed. SNPs at bp - 219 and - 163 occurred in 9% among 109 blood donors reducing UGT1A4 transcription by 40%. UGT1A4 transcription was dioxin inducible. Reporter gene experiments identified 2 xenobiotic response elements (XRE), which were functionally confirmed by mutagenesis analyses, and binding was demonstrated by electromobility shift assays. Constitutive human UGT1A4 gene expression and induction was aryl hydrocarbon receptor (AhR)-dependent, and reduced in the presence of SNPs at bp - 219 and - 163. AhR-mediated regulation of the human UGT1A4 gene by two XRE and a modulation by naturally occurring genetic variability by SNPs is demonstrated, which indicates gene-environment interaction with potential relevance for drug metabolism.

Genetic variability of aryl hydrocarbon receptor (AhR)-mediated regulation of the human UDP glucuronosyltransferase (UGT) 1A4 gene

International Nuclear Information System (INIS)

Erichsen, Thomas J.; Ehmer, Ursula; Kalthoff, Sandra; Lankisch, Tim O.; Mueller, Tordis M.; Munzel, Peter A.; Manns, Michael P.; Strassburg, Christian P.

2008-01-01

UDP glucuronosyltransferases (UGTs) play an important role for drug detoxification and toxicity. UGT function is genetically modulated by single nucleotide polymorphisms (SNPs) which lead to the expression of functionally altered protein, or altered expression levels. UGT1A4 activity includes anticonvulsants, antidepressants and environmental mutagens. In this study the induction of the human UGT1A4 gene and a potential influence of genetic variation in its promoter region were analyzed. SNPs at bp - 219 and - 163 occurred in 9% among 109 blood donors reducing UGT1A4 transcription by 40%. UGT1A4 transcription was dioxin inducible. Reporter gene experiments identified 2 xenobiotic response elements (XRE), which were functionally confirmed by mutagenesis analyses, and binding was demonstrated by electromobility shift assays. Constitutive human UGT1A4 gene expression and induction was aryl hydrocarbon receptor (AhR)-dependent, and reduced in the presence of SNPs at bp - 219 and - 163. AhR-mediated regulation of the human UGT1A4 gene by two XRE and a modulation by naturally occurring genetic variability by SNPs is demonstrated, which indicates gene-environment interaction with potential relevance for drug metabolism

Association between MC4R rs17782313 Polymorphism and Overeating Behaviours

Science.gov (United States)

Yilmaz, Zeynep; Davis, Caroline; Loxton, Natalie J.; Kaplan, Allan S.; Levitan, Robert D.; Carter, Jacqueline C.; Kennedy, James L.

2014-01-01

Background/Objectives Melanocortins play a crucial role in appetite and weight regulation. Although the melanocortin 4 receptor (MC4R) gene has been repeatedly linked to obesity and antipsychotic-induced weight gain, the mechanism behind how it leads to this effect in still undetermined. The goal of this study was to conduct an in-depth and sophisticated analysis of MC4R polymorphisms, body mass index (BMI), eating behaviour, and depressed mood. Subjects/Methods We genotyped 328 individuals of European ancestry on the following MC4R markers based on the relevant literature on obesity and antipsychotic-induced weight gain: rs571312, rs17782313, rs489693, rs11872992, and rs8087522. Height and weight were measured, and information on depressed mood and overeating behaviours was obtained during the in-person assessment. Results BMI was associated with rs17782313 C allele; however this finding did not survive correction for multiple testing (p=0.018). Although rs17782313 was significantly associated with depressed mood and overeating behaviours, tests of indirect effects indicated that emotional eating and food cravings, rather than depressed mood, uniquely accounted for the effect of this marker and BMI (n=152). Conclusions To our knowledge, this is the first study to investigate the link between MC4R rs17782313, mood and overeating behaviour, as well as to demonstrate possible mechanisms behind MC4R’s influence on body weight. If replicated in a larger sample, these results may have important clinical implications, including potential for the use of MC4R agonists in the treatment of obesity and disordered eating. PMID:24827639

The association between dopamine receptor (DRD4) gene polymorphisms and second language learning style and behavioral variability in undergraduate students in Turkey.

Science.gov (United States)

Maras Atabay, Meltem; Safi Oz, Zehra; Kurtman, Elvan

2014-08-01

The dopamine D4 receptor gene (DRD4) encodes a receptor for dopamine, a chemical messenger used in the brain. One variant of the DRD4 gene, the 7R allele, is believed to be associated with attention deficit hyperactivity disorder (ADHD). The aim of this study was to investigate the relationships between repeat polymorphisms in dopamine DRD4 and second language learning styles such as visual (seeing), tactile (touching), auditory (hearing), kinesthetic (moving) and group/individual learning styles, as well as the relationships among DRD4 gene polymorphisms and ADHD in undergraduate students. A total of 227 students between the ages of 17-21 years were evaluated using the Wender Utah rating scale and DSM-IV diagnostic criteria for ADHD. Additionally, Reid's perceptual learning style questionnaire for second language learning style was applied. In addition, these students were evaluated for social distress factors using the list of Threatening Events (TLE); having had no TLE, having had just one TLE or having had two or more TLEs within the previous 6 months before the interview. For DRD4 gene polymorphisms, DNA was extracted from whole blood using the standard phenol/chloroform method and genotyped using polymerase chain reaction. Second language learners with the DRD4.7+ repeats showed kinaesthetic and auditory learning styles, while students with DRD4.7-repeats showed visual, tactile and group learning, and also preferred the more visual learning styles [Formula: see text]. We also demonstrated that the DRD4 polymorphism significantly affected the risk effect conferred by an increasing level of exposure to TLE.

Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

DEFF Research Database (Denmark)

Tarnow, L; Cambien, Francois; Rossing, P

1996-01-01

with proliferative retinopathy and without diabetic retinopathy was found either: 77 (50%) / 66 (42%) / 13 (8%) vs. 42 (63%) / 22 (33%) / 3 (4%) had AA/AC/CC genotypes, respectively. CONCLUSIONS: The A1166-->C polymorphism in the angiotensin-II type 1 receptor gene does not contribute to the genetic susceptibility...... is present particularly in vascular smooth muscle cells, myocardium and the kidney. A transversion of adenine to cytosine at nucleotide position 1166 in the gene coding for the angiotensin-II type 1 receptor has been associated with hypertension in the non-diabetic population. METHODS: We studied...... the relationship between the A1166-->C polymorphism in the angiotensin-II type 1 receptor gene in patients with insulin dependent diabetes mellitus (IDDM) and diabetic nephropathy (121 men, 77 women, age 41 +/- 10 years, diabetes duration 27 +/- 8 years) and in IDDM patients with normoalbuminuria (116 men, 74...

Dopamine D4 Receptor Gene Polymorphism in a Sample of Egyptian Children With Attention-Deficit Hyperactivity Disorder (ADHD).

Science.gov (United States)

ElBaz Mohamed, Farida; Kamal, Tarek Mostafa; Zahra, Sally Soliman; Khfagy, Mona Abdel Hakiem; Youssef, Azza Mohamed

2017-02-01

This study aimed to detect DRD4 receptor gene polymorphisms in attention-deficit hyperactivity disorder (ADHD) children and to correlate their phenotype-genotype. Fifty children with ADHD were diagnosed by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria and were subjected to Conners Parent Rating Scale. All cases and controls were subjected to history taking, physical examination, IQ assessment, and dopamine receptor D4 (DRD4) exon 3 genotyping. The 7-repeat allele was present only in controls, whereas 2-repeat allele was present in the ADHD children (heterozygous 2-repeat allele in 16% and homozygous in 26% of cases). Eight percent of cases had homozygous 4-repeat allele vs 28% of controls, whereas 10% of cases had heterozygous 4-repeat allele vs 6% of controls, with its predominance in controls. The 2-repeat and 4-repeat alleles have been associated with more inattention, hyperactivity, and impulsivity phenotypes. In conclusion, children with ADHD had a significant presence of the 2-repeat allele and absence of the 7-repeat allele.

The association between the nicotinic acetylcholine receptor α4 subunit gene (CHRNA4 rs1044396 and Internet gaming disorder in Korean male adults.

Directory of Open Access Journals (Sweden)

Jo-Eun Jeong

Full Text Available The primary aim of this study was to investigate the genetic predisposition of Internet gaming disorder (IGD, and the secondary aim was to compare the results to those of alcohol dependence (AD. Two independent case-control studies were conducted. A total of 30 male participants with IGD, diagnosed according to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5 criteria, and 30 sex-matched controls participated in study 1. We designed targeted exome sequencing (TES to test for 72 candidate genes that have been implicated in the pathogenesis of addiction. The genes included seven neurotransmitter (dopamine, serotonin, glutamate, r-aminobutyric acid (GABA, norepinephrine, acetylcholine, and opioid system genes. A total of 31 male in-patients with AD and 29 normal male controls (NC were enrolled in study 2. The same 72 genes included in study 1 and ten additional genes related to alcohol-metabolic enzyme were selected as the target genes, and we identified the genetic variants using the same method (TES. The IGD group had a lower frequency of the T allele of rs1044396 in the nicotinic acetylcholine receptor alpha 4 subunit (CHRNA4, and this variant represents a protective allele against IGD. However, we did not find a significant difference in the polymorphisms of the 72 genes that encode neurotransmitter systems between the AD and NC groups. This study demonstrated that rs1044396 of CHRNA4 was significantly associated with IGD.

Variants in the dopamine-4-receptor gene promoter are not associated with sensation seeking in skiers.

Directory of Open Access Journals (Sweden)

Cynthia J Thomson

Full Text Available Sensation seeking is a personality trait that has been associated with disinhibited behaviours including substance use and gambling, but also with high-risk sport practices including skydiving, paragliding, and downhill skiing. Twin studies have shown that sensation seeking is moderately heritable, and candidate genes encoding components involved in dopaminergic transmission have been investigated as contributing to this type of behaviour. To determine whether variants in the regulatory regions of the dopamine-4-receptor gene (DRD4 influenced sport-specific sensation seeking, we analyzed five polymorphisms (-1106T/C, -906T/C, -809G/A, -291C/T, 120-bp duplication in the promoter region of the gene in a cohort of skiers and snowboarders (n = 599 that represented a broad range of sensation seeking behaviours. We grouped subjects by genotype at each of the five loci and compared impulsive sensation seeking and domain-specific (skiing sensation seeking between groups. There were no significant associations between genotype(s and general or domain-specific sensation seeking in the skiers and snowboarders, suggesting that while DRD4 has previously been implicated in sensation seeking, the promoter variants investigated in this study do not contribute to sensation seeking in this athlete population.

Chromosomal localization of the gonadotropin-releasing hormone receptor gene to human chromosome 4q13. 1-q21. 1 and mouse chromosome 5

Energy Technology Data Exchange (ETDEWEB)

Kaiser, U.B.; Dushkin, H.; Beier, D.R.; Chin, W.W. (Harvard Medical School, Boston, MA (United States)); Altherr, M.R. (Los Alamos National Lab., NM (United States))

1994-04-01

The gonadotropin-releasing hormone receptor (GRHR) is a G-protein-coupled receptor on the cell surface of pituitary gonadotropes, where it serves to transduce signals from the extracellular ligand, the hypothalamic factor gonadotropin-releasing hormone, and to modulate the synthesis and secretion of luteinizing hormone and follicle-stimulating hormone. The authors have localized the GRHR gene to the q13.1-q21.1 region of the human chromosome 4 using mapping panels of human/rodent somatic cell hybrids containing different human chromosomes or different regions of human chromosome 4. Furthermore, using linkage analysis of single-strand conformational polymorphisms, the murine GRHR gene was localized to mouse chromosome 5, linked to the endogenous retroviral marker Pmv-11. This is consistent with the evolutionary conservation of homology between these two regions, as has been previously suggested from comparative mapping of several other loci. The localization of the GRHR gene may be useful in the study of disorders of reproduction. 22 refs., 2 figs.

Identification of novel androgen receptor target genes in prostate cancer

Directory of Open Access Journals (Sweden)

Gerald William L

2007-06-01

Full Text Available Abstract Background The androgen receptor (AR plays critical roles in both androgen-dependent and castrate-resistant prostate cancer (PCa. However, little is known about AR target genes that mediate the receptor's roles in disease progression. Results Using Chromatin Immunoprecipitation (ChIP Display, we discovered 19 novel loci occupied by the AR in castrate resistant C4-2B PCa cells. Only four of the 19 AR-occupied regions were within 10-kb 5'-flanking regulatory sequences. Three were located up to 4-kb 3' of the nearest gene, eight were intragenic and four were in gene deserts. Whereas the AR occupied the same loci in C4-2B (castrate resistant and LNCaP (androgen-dependent PCa cells, differences between the two cell lines were observed in the response of nearby genes to androgens. Among the genes strongly stimulated by DHT in C4-2B cells – D-dopachrome tautomerase (DDT, Protein kinase C delta (PRKCD, Glutathione S- transferase theta 2 (GSTT2, Transient receptor potential cation channel subfamily V member 3 (TRPV3, and Pyrroline-5-carboxylate reductase 1 (PYCR1 – most were less strongly or hardly stimulated in LNCaP cells. Another AR target gene, ornithine aminotransferase (OAT, was AR-stimulated in a ligand-independent manner, since it was repressed by AR siRNA knockdown, but not stimulated by DHT. We also present evidence for in vivo AR-mediated regulation of several genes identified by ChIP Display. For example, PRKCD and PYCR1, which may contribute to PCa cell growth and survival, are expressed in PCa biopsies from primary tumors before and after ablation and in metastatic lesions in a manner consistent with AR-mediated stimulation. Conclusion AR genomic occupancy is similar between LNCaP and C4-2B cells and is not biased towards 5' gene flanking sequences. The AR transcriptionally regulates less than half the genes nearby AR-occupied regions, usually but not always, in a ligand-dependent manner. Most are stimulated and a few are

Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity.

Science.gov (United States)

Garcia, Justin R; MacKillop, James; Aller, Edward L; Merriwether, Ann M; Wilson, David Sloan; Lum, J Koji

2010-11-30

Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand") and report a more than 50% increase in instances of sexual infidelity. DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.

Associations between Dopamine D4 Receptor Gene Variation with Both Infidelity and Sexual Promiscuity

Science.gov (United States)

Garcia, Justin R.; MacKillop, James; Aller, Edward L.; Merriwether, Ann M.; Wilson, David Sloan; Lum, J. Koji

2010-01-01

Background Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. Methodology/Principal Findings We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a “one-night stand”) and report a more than 50% increase in instances of sexual infidelity. Conclusions/Significance DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism. PMID:21152404

Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity.

Directory of Open Access Journals (Sweden)

Justin R Garcia

2010-11-01

Full Text Available Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection, little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR polymorphism in exon III of the human dopamine D4 receptor gene (DRD4 has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity.We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+ report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand" and report a more than 50% increase in instances of sexual infidelity.DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.

Indirubin, a component of Ban-Lan-Gen, activates CYP3A4 gene transcription through the human pregnane X receptor.

Science.gov (United States)

Kumagai, Takeshi; Aratsu, Yusuke; Sugawara, Ryosuke; Sasaki, Takamitsu; Miyairi, Shinichi; Nagata, Kiyoshi

2016-04-01

Ban-Lan-Gen is the common name for the dried roots of indigo plants, including Polygonum tinctorium, Isatis indigotica, Isatis tinctoria, and Strobilanthes cusia. Ban-Lan-Gen is frequently used as an anti-inflammatory and an anti-viral for the treatment of hepatitis, influenza, and various types of inflammation. One of the cytochrome P450 (CYP) enzymes, CYP3A4, is responsible for the metabolism of a wide variety of xenobiotics, including an estimated 60% of all clinically used drugs. In this study, we investigated the effect of Ban-Lan-Gen on the transcriptional activation of the CYP3A4 gene. Ban-Lan-Gen extract increased CYP3A4 gene reporter activity in a dose-dependent manner. Indirubin, one of the biologically active ingredients in the Ban-Lan-Gen, also dose-dependently increased CYP3A4 gene reporter activity. Expression of short hairpin RNA for the human pregnane X receptor (hPXR-shRNA) inhibited CYP3A4 gene reporter activity, and overexpression of human PXR increased indirubin- and rifampicin-induced CYP3A4 gene reporter activity. Furthermore, indirubin induced CYP3A4 mRNA expression in HepG2 cells. Taken together, these results indicate that indirubin, a component of Ban-Lan-Gen, activated CYP3A4 gene transcription through the activation of the human PXR. Copyright © 2016. Published by Elsevier Ltd.

Assessment of human pregnane X receptor involvement in pesticide-mediated activation of CYP3A4 gene.

Science.gov (United States)

Matsubara, Tsutomu; Noracharttiyapot, Wachiraporn; Toriyabe, Takayoshi; Yoshinari, Kouichi; Nagata, Kiyoshi; Yamazoe, Yasushi

2007-05-01

Assessment of foreign chemical inducibility on CYP3A4 is necessary to optimize drug therapies. The properties of chemicals such as pesticides, however, are not well investigated. In the present study, properties of various pesticides on human CYP3A4 induction have been tested using HepG2-derived cells stably expressing the CYP3A4 promoter/enhancer (3-1-10 cells) and the human pregnane X receptor (hPXR)-small interfering RNA (siRNA) system. Among the examined pesticides, 13 pesticides were observed to activate the CYP3A4 gene. Surprisingly, pyributicarb was found to increase the CYP3A4 reporter activity at 0.1 to 1 microM more strongly than typical CYP3A4 inducer rifampicin. Expression of hPXR-siRNA clearly diminished the pyributicarb-stimulated CYP3A4 reporter activity in 3-1-10 cells and decreased the endogenous CYP3A4 mRNA levels in HepG2 cells. Pyributicarb caused enhancement of CYP3A4-derived reporter activity in mouse livers introduced with hPXR by adenovirus. These results indicate pyributicarb as a potent activator of CYP3A4 gene, suggesting the existence of pesticides leading to CYP3A4 induction in our environment.

Anxiogenic effects of developmental bisphenol A exposure are associated with gene expression changes in the juvenile rat amygdala and mitigated by soy.

Directory of Open Access Journals (Sweden)

Heather B Patisaul

Full Text Available Early life exposure to Bisphenol A (BPA, a component of polycarbonate plastics and epoxy resins, alters sociosexual behavior in numerous species including humans. The present study focused on the ontogeny of these behavioral effects beginning in adolescence and assessed the underlying molecular changes in the amygdala. We also explored the mitigating potential of a soy-rich diet on these endpoints. Wistar rats were exposed to BPA via drinking water (1 mg/L from gestation through puberty, and reared on a soy-based or soy-free diet. A group exposed to ethinyl estradiol (50 µg/L and a soy-free diet was used as a positive estrogenic control. Animals were tested as juveniles or adults for anxiety-like and exploratory behavior. Assessment of serum BPA and genistein (GEN, a soy phytoestrogen, confirmed that internal dose was within a human-relevant range. BPA induced anxiogenic behavior in juveniles and loss of sexual dimorphisms in adult exploratory behavior, but only in the animals reared on the soy-free diet. Expression analysis revealed a suite of genes, including a subset known to mediate sociosexual behavior, associated with BPA-induced juvenile anxiety. Notably, expression of estrogen receptor beta (Esr2 and two melanocortin receptors (Mc3r, Mc4r were downregulated. Collectively, these results show that behavioral impacts of BPA can manifest during adolescence, but wane in adulthood, and may be mitigated by diet. These data also reveal that, because ERβ and melanocortin receptors are crucial to their function, oxytocin/vasopressin signaling pathways, which have previously been linked to human affective disorders, may underlie these behavioral outcomes.

Cloning of human genes encoding novel G protein-coupled receptors

Energy Technology Data Exchange (ETDEWEB)

Marchese, A.; Docherty, J.M.; Heiber, M. [Univ. of Toronto, (Canada)] [and others

1994-10-01

We report the isolation and characterization of several novel human genes encoding G protein-coupled receptors. Each of the receptors contained the familiar seven transmembrane topography and most closely resembled peptide binding receptors. Gene GPR1 encoded a receptor protein that is intronless in the coding region and that shared identity (43% in the transmembrane regions) with the opioid receptors. Northern blot analysis revealed that GPR1 transcripts were expressed in the human hippocampus, and the gene was localized to chromosome 15q21.6. Gene GPR2 encoded a protein that most closely resembled an interleukin-8 receptor (51% in the transmembrane regions), and this gene, not expressed in the six brain regions examined, was localized to chromosome 17q2.1-q21.3. A third gene, GPR3, showed identity (56% in the transmembrane regions) with a previously characterized cDNA clone from rat and was localized to chromosome 1p35-p36.1. 31 refs., 5 figs., 1 tab.

Evolution of the vertebrate insulin receptor substrate (Irs) gene family.

Science.gov (United States)

Al-Salam, Ahmad; Irwin, David M

2017-06-23

Insulin receptor substrate (Irs) proteins are essential for insulin signaling as they allow downstream effectors to dock with, and be activated by, the insulin receptor. A family of four Irs proteins have been identified in mice, however the gene for one of these, IRS3, has been pseudogenized in humans. While it is known that the Irs gene family originated in vertebrates, it is not known when it originated and which members are most closely related to each other. A better understanding of the evolution of Irs genes and proteins should provide insight into the regulation of metabolism by insulin. Multiple genes for Irs proteins were identified in a wide variety of vertebrate species. Phylogenetic and genomic neighborhood analyses indicate that this gene family originated very early in vertebrae evolution. Most Irs genes were duplicated and retained in fish after the fish-specific genome duplication. Irs genes have been lost of various lineages, including Irs3 in primates and birds and Irs1 in most fish. Irs3 and Irs4 experienced an episode of more rapid protein sequence evolution on the ancestral mammalian lineage. Comparisons of the conservation of the proteins sequences among Irs paralogs show that domains involved in binding to the plasma membrane and insulin receptors are most strongly conserved, while divergence has occurred in sequences involved in interacting with downstream effector proteins. The Irs gene family originated very early in vertebrate evolution, likely through genome duplications, and in parallel with duplications of other components of the insulin signaling pathway, including insulin and the insulin receptor. While the N-terminal sequences of these proteins are conserved among the paralogs, changes in the C-terminal sequences likely allowed changes in biological function.

NCBI nr-aa BLAST: CBRC-TSYR-01-0189 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-TSYR-01-0189 ref|NP_001116609.1| melanocortin 3 receptor [Sus scrofa] emb|CAN13145.1| mela...nocortin 3 receptor [Sus scrofa] gb|ABU62784.1| melanocortin-3 receptor [Sus scrofa] NP_001116609.1 2e-86 86% ...

Identification and functional analysis of pheromone and receptor genes in the B3 mating locus of Pleurotus eryngii.

Science.gov (United States)

Kim, Kyung-Hee; Kang, Young Min; Im, Chak Han; Ali, Asjad; Kim, Sun Young; Je, Hee-Jeong; Kim, Min-Keun; Rho, Hyun Su; Lee, Hyun Sook; Kong, Won-Sik; Ryu, Jae-San

2014-01-01

Pleurotus eryngii has recently become a major cultivated mushroom; it uses tetrapolar heterothallism as a part of its reproductive process. Sexual development progresses only when the A and B mating types are compatible. Such mating incompatibility occasionally limits the efficiency of breeding programs in which crossing within loci-shared strains or backcrossing strategies are employed. Therefore, understanding the mating system in edible mushroom fungi will help provide a short cut in the development of new strains. We isolated and identified pheromone and receptor genes in the B3 locus of P. eryngii and performed a functional analysis of the genes in the mating process by transformation. A genomic DNA library was constructed to map the entire mating-type locus. The B3 locus was found to contain four pheromone precursor genes and four receptor genes. Remarkably, receptor PESTE3.3.1 has just 34 amino acid residues in its C-terminal cytoplasmic region; therefore, it seems likely to be a receptor-like gene. Real-time quantitative RT-PCR (real-time qRT-PCR) revealed that most pheromone and receptor genes showed significantly higher expression in monokaryotic cells than dikaryotic cells. The pheromone genes PEphb3.1 and PEphb3.3 and the receptor gene PESTE3.3.1 were transformed into P5 (A3B4). The transformants were mated with a tester strain (A4B4), and the progeny showed clamp connections and a normal fruiting body, which indicates the proposed role of these genes in mating and fruiting processes. This result also confirms that PESTE3.3.1 is a receptor gene. In this study, we identified pheromone and receptor genes in the B3 locus of P. eryngii and found that some of those genes appear to play a role in the mating and fruiting processes. These results might help elucidate the mechanism of fruiting differentiation and improve breeding efficiency.

Self-esteem in remitted patients with mood disorders is not associated with the dopamine receptor D4 and the serotonin transporter genes.

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Serretti, A; Macciardi, F; Di Bella, D; Catalano, M; Smeraldi, E

1998-08-17

Disturbances of the dopaminergic and serotoninergic neurotransmitter systems have been implicated in the pathogenesis of depressive symptoms. Associations have been reported between markers of the two neurotransmitter systems and the presence of illness or severity of depressive episodes, but no attention has been focused on the periods of remission. The present report focuses on a possible association of self-esteem in remitted mood disorder patients with the functional polymorphism located in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) and the dopamine receptor D4 (DRD4). Inpatients (N=162) affected by bipolar (n=103) and unipolar (n=59) disorder (DSM III-R) were assessed by the Self-Esteem Scale (SES, Rosenberg, 1965) and were typed for DRD4 and 5-HTTLPR (n=58 subjects) variants at the third exon using polymerase chain reaction (PCR) techniques. Neither DRD4 nor 5-HTTLPR variants were associated with SES scores, and consideration of possible stratification effects such as sex and psychiatric diagnosis did not reveal any association either. The serotonin transporter and dopamine receptor D4 genes do not, therefore, influence self-esteem in remitted mood disorder subjects.

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese.

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Ebstein, Richard P; Monakhov, Mikhail V; Lu, Yunfeng; Jiang, Yushi; Lai, Poh San; Chew, Soo Hong

2015-08-22

Twin and family studies suggest that political attitudes are partially determined by an individual's genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United States study provisionally identified this gene with political attitude along a liberal-conservative axis albeit contingent upon number of friends. In a large sample of 1771 Han Chinese university students in Singapore, we observed a significant main effect of association between the DRD4 exon III variable number of tandem repeats and political attitude. Subjects with two copies of the 4-repeat allele (4R/4R) were significantly more conservative. Our results provided evidence for a role of the DRD4 gene variants in contributing to individual differences in political attitude particularly in females and more generally suggested that associations between individual genes, and neurochemical pathways, contributing to traits relevant to the social sciences can be provisionally identified. © 2015 The Author(s).

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese

Science.gov (United States)

Ebstein, Richard P.; Monakhov, Mikhail V.; Lu, Yunfeng; Jiang, Yushi; Lai, Poh San; Chew, Soo Hong

2015-01-01

Twin and family studies suggest that political attitudes are partially determined by an individual's genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United States study provisionally identified this gene with political attitude along a liberal–conservative axis albeit contingent upon number of friends. In a large sample of 1771 Han Chinese university students in Singapore, we observed a significant main effect of association between the DRD4 exon III variable number of tandem repeats and political attitude. Subjects with two copies of the 4-repeat allele (4R/4R) were significantly more conservative. Our results provided evidence for a role of the DRD4 gene variants in contributing to individual differences in political attitude particularly in females and more generally suggested that associations between individual genes, and neurochemical pathways, contributing to traits relevant to the social sciences can be provisionally identified. PMID:26246555

NCBI nr-aa BLAST: CBRC-DRER-19-0035 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DRER-19-0035 ref|NP_775386.1| melanocortin 5a receptor [Danio rerio] gb|AAL85495.1| mela...nocortin 5a receptor [Danio rerio] gb|AAO24747.1| melanocortin 5b receptor [Danio rerio] NP_775386.1 1e-180 100% ...

NR4A nuclear receptors are orphans but not lonesome.

Science.gov (United States)

Kurakula, Kondababu; Koenis, Duco S; van Tiel, Claudia M; de Vries, Carlie J M

2014-11-01

The NR4A subfamily of nuclear receptors consists of three mammalian members: Nur77, Nurr1, and NOR-1. The NR4A receptors are involved in essential physiological processes such as adaptive and innate immune cell differentiation, metabolism and brain function. They act as transcription factors that directly modulate gene expression, but can also form trans-repressive complexes with other transcription factors. In contrast to steroid hormone nuclear receptors such as the estrogen receptor or the glucocorticoid receptor, no ligands have been described for the NR4A receptors. This lack of known ligands might be explained by the structure of the ligand-binding domain of NR4A receptors, which shows an active conformation and a ligand-binding pocket that is filled with bulky amino acid side-chains. Other mechanisms, such as transcriptional control, post-translational modifications and protein-protein interactions therefore seem to be more important in regulating the activity of the NR4A receptors. For Nur77, over 80 interacting proteins (the interactome) have been identified so far, and roughly half of these interactions has been studied in more detail. Although the NR4As show some overlap in interacting proteins, less information is available on the interactome of Nurr1 and NOR-1. Therefore, the present review will describe the current knowledge on the interactomes of all three NR4A nuclear receptors with emphasis on Nur77. Copyright © 2014 Elsevier B.V. All rights reserved.

Genetic diversity of bitter taste receptor gene family in Sichuan ...

Indian Academy of Sciences (India)

Previous research had revealed that chicken has only three bitter taste receptor genes (Tas2r1, ... Journal of Genetics, DOI 10.1007/s12041-016-0684-4, Vol. ..... between red-winged blackbirds and European starlings. ... Academic Press,.

The pea branching RMS2 gene encodes the PsAFB4/5 auxin receptor and is involved in an auxin-strigolactone regulation loop.

Science.gov (United States)

Ligerot, Yasmine; de Saint Germain, Alexandre; Waldie, Tanya; Troadec, Christelle; Citerne, Sylvie; Kadakia, Nikita; Pillot, Jean-Paul; Prigge, Michael; Aubert, Grégoire; Bendahmane, Abdelhafid; Leyser, Ottoline; Estelle, Mark; Debellé, Frédéric; Rameau, Catherine

2017-12-01

Strigolactones (SLs) are well known for their role in repressing shoot branching. In pea, increased transcript levels of SL biosynthesis genes are observed in stems of highly branched SL deficient (ramosus1 (rms1) and rms5) and SL response (rms3 and rms4) mutants indicative of negative feedback control. In contrast, the highly branched rms2 mutant has reduced transcript levels of SL biosynthesis genes. Grafting studies and hormone quantification led to a model where RMS2 mediates a shoot-to-root feedback signal that regulates both SL biosynthesis gene transcript levels and xylem sap levels of cytokinin exported from roots. Here we cloned RMS2 using synteny with Medicago truncatula and demonstrated that it encodes a putative auxin receptor of the AFB4/5 clade. Phenotypes similar to rms2 were found in Arabidopsis afb4/5 mutants, including increased shoot branching, low expression of SL biosynthesis genes and high auxin levels in stems. Moreover, afb4/5 and rms2 display a specific resistance to the herbicide picloram. Yeast-two-hybrid experiments supported the hypothesis that the RMS2 protein functions as an auxin receptor. SL root feeding using hydroponics repressed auxin levels in stems and down-regulated transcript levels of auxin biosynthesis genes within one hour. This auxin down-regulation was also observed in plants treated with the polar auxin transport inhibitor NPA. Together these data suggest a homeostatic feedback loop in which auxin up-regulates SL synthesis in an RMS2-dependent manner and SL down-regulates auxin synthesis in an RMS3 and RMS4-dependent manner.

Association of ghrelin receptor gene polymorphism with bulimia nervosa in a Japanese population.

Science.gov (United States)

Miyasaka, K; Hosoya, H; Sekime, A; Ohta, M; Amono, H; Matsushita, S; Suzuki, K; Higuchi, S; Funakoshi, A

2006-09-01

Eating disorders (EDs) have a highly heterogeneous etiology and multiple genetic factors might contribute to their pathogenesis. Ghrelin, a novel growth hormone-releasing peptide, enhances appetite and increases food intake, and human ghrelin plasma levels are inversely correlated with body mass index. In the present study, we examined the 171T/C polymorphism of the ghrelin receptor (growth hormone secretagogue receptor, GHSR) gene in patients diagnosed with EDs, because the subjects having ghrelin gene polymorphism (Leu72Met) was not detected in a Japanese population, previously. In addition, beta3 adrenergic receptor gene polymorphism (Try64Arg) and cholecystokinin (CCK)-A receptor (R) gene polymorphism (-81A/G, -128G/T), which are both associated with obesity, were investigated. The subjects consisted of 228 Japanese patients with EDs [96 anorexia nervosa (AN), 116 bulimia nervosa (BN) and 16 not otherwise specified (NOS)]. The age- and gender-matched control group consisted of 284 unrelated Japanese subjects. The frequency of the CC type of the GHSR gene was significantly higher in BN subjects than in control subjects (chi(2) = 4.47, p = 0.035, odds ratio = 2.05, Bonferroni correction: p = 0.070), while the frequency in AN subjects was not different from that in controls. The distribution of neither beta3 adrenergic receptor gene nor CCK-AR polymorphism differed between EDs and control subjects. Therefore, the CC type of GHSR gene polymorphism (171T/C) is a risk factor for BN, but not for AN.

Effects of α-Melanocortin Enantiomers on Acetaminophen-Induced Hepatotoxicity in CBA Mice

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Dražen Vikić-Topić

2009-12-01

Full Text Available Proteins and peptides in mammals are based exclusively on L-amino acids. Recent investigations show that D-amino acids exhibit physiological effects in vivo, despite of their very small quantities. We have investigated the hepatoprotective effects of the Land D-enantiomers of α-melanocortin peptide (α-MSH. The results showed that peptideenantiomerism is related to the protective effects of melanocortin peptides in vivo. L-α-MSH exhibited potent hepatoprotective effect in the experimental model of acetaminophen induced hepatotoxicity in male CBA mice, while its D-mirror image was inefficient. Furthermore, the antibody to the L-peptide did not recognize the D-structure. The results indicate that the opposite peptide configuration may be used to modulate its function and metabolism in vivo and in vitro.

Human estrogen receptor (ESR) gene locus: PssI dimorphism

Energy Technology Data Exchange (ETDEWEB)

Coleman, R T; Taylor, J E; Frossard, P M [California Biotechnology Inc., Mountain View, CA (USA); Shine, J J [Garvan Institute, Darlinghurst (Australia)

1988-07-25

pESR-2, a 2.1 kb partial cDNA containing the entire translated sequence of the human estrogen receptor mRNA isolated from MCF-7 human breast cancer cells, was subcloned in the Eco RI site of pBR322. PssI (PuGGNCCPy) identifies a single two-allele polymorphism with bands at either 1.7 or 1.4 kb, as well as invariant bands at 12.6, 9.3, 4.1, 3.7, 2.4, 2.2, and 1.2 kb. Its frequency was studied in 77 unrelated North American Caucasians. The human estrogen receptor gene has been localized to 6q24 -- q27 by in situ hybridization. Co-dominant segregation is demonstrated in one family (8 individuals).

Oleocanthal Modulates Estradiol-Induced Gene Expression Involving Estrogen Receptor α.

Science.gov (United States)

Keiler, Annekathrin Martina; Djiogue, Sefirin; Ehrhardt, Tino; Zierau, Oliver; Skaltsounis, Leandros; Halabalaki, Maria; Vollmer, Günter

2015-09-01

Oleocanthal is a bioactive compound from olive oil. It has attracted considerable attention as it is anti-inflammatory, antiproliferative, and has been shown to possess neuroprotective properties in vitro and in vivo. Delineated from its polyphenolic structure, the aim of this study was to characterize oleocanthal towards estrogenic properties. This might contribute to partly explain the beneficial effects described for the Mediterranean diet. Estrogenic properties of oleocanthal were assessed by different methods: a) stimulation of reporter gene activity in MVLN or RNDA cells either expressing estrogen receptor α or β, b) stimulation of luciferase reporter gene activity in U2OS osteosarcoma cells expressing estrogen receptor α or β, and c) elucidation of the impact on estradiol-induced gene expression in U2OS cells transduced with both estrogen receptors. Depending on the cell line origin, oleocanthal inhibited luciferase activity (MVLN, U2OS-estrogen receptor β) or weakly induced reporter gene activity at 10 µM in U2OS-estrogen receptor α cells. However, oleocanthal inhibited stimulation of luciferase activity by estradiol from both estrogen receptors. Oleocanthal, if given alone, did not stimulate gene expression in U2OS cells, but it significantly modulated the response of estradiol. Oleocanthal enhanced the effect of estradiol on the regulation of those genes, which are believed to be regulated through heterodimeric estrogen receptors. As the estrogenic response pattern of oleocanthal is rather unique, we compared the results obtained with oleacein. Oleocanthal binds to both estrogen receptors inducing estradiol-agonistic or antiagonistic effects depending on the cell line. Regarding regulation of gene expression in U2OS-estrogen receptor α/β cells, oleocanthal and oleacein enhanced estradiol-mediated regulation of heterodimer-regulated genes. Georg Thieme Verlag KG Stuttgart · New York.

Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins

International Nuclear Information System (INIS)

Teutschbein, Janka; Haydn, Johannes M; Samans, Birgit; Krause, Michael; Eilers, Martin; Schartl, Manfred; Meierjohann, Svenja

2010-01-01

Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase) triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1), early growth response 1 (Egr1), osteopontin (Opn), insulin-like growth factor binding protein 3 (Igfbp3), dual-specificity phosphatase 4 (Dusp4), and tumor-associated antigen L6 (Taal6). Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute new possible molecular players in melanoma development

Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins

Directory of Open Access Journals (Sweden)

Krause Michael

2010-07-01

Full Text Available Abstract Background Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Methods Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Results Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1, early growth response 1 (Egr1, osteopontin (Opn, insulin-like growth factor binding protein 3 (Igfbp3, dual-specificity phosphatase 4 (Dusp4, and tumor-associated antigen L6 (Taal6. Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Conclusion Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute

Arabidopsis ETR1 and ERS1 Differentially Repress the Ethylene Response in Combination with Other Ethylene Receptor Genes1[W

Science.gov (United States)

Liu, Qian; Wen, Chi-Kuang

2012-01-01

The ethylene response is negatively regulated by a family of five ethylene receptor genes in Arabidopsis (Arabidopsis thaliana). The five members of the ethylene receptor family can physically interact and form complexes, which implies that cooperativity for signaling may exist among the receptors. The ethylene receptor gene mutations etr1-1(C65Y)(for ethylene response1-1), ers1-1(I62P) (for ethylene response sensor1-1), and ers1C65Y are dominant, and each confers ethylene insensitivity. In this study, the repression of the ethylene response by these dominant mutant receptor genes was examined in receptor-defective mutants to investigate the functional significance of receptor cooperativity in ethylene signaling. We showed that etr1-1(C65Y), but not ers1-1(I62P), substantially repressed various ethylene responses independent of other receptor genes. In contrast, wild-type receptor genes differentially supported the repression of ethylene responses by ers1-1(I62P); ETR1 and ETHYLENE INSENSITIVE4 (EIN4) supported ers1-1(I62P) functions to a greater extent than did ERS2, ETR2, and ERS1. The lack of both ETR1 and EIN4 almost abolished the repression of ethylene responses by ers1C65Y, which implied that ETR1 and EIN4 have synergistic effects on ers1C65Y functions. Our data indicated that a dominant ethylene-insensitive receptor differentially repressed ethylene responses when coupled with a wild-type ethylene receptor, which supported the hypothesis that the formation of a variety of receptor complexes may facilitate differential receptor signal output, by which ethylene responses can be repressed to different extents. We hypothesize that plants can respond to a broad ethylene concentration range and exhibit tissue-specific ethylene responsiveness with differential cooperation of the multiple ethylene receptors. PMID:22227969

Receptor for the F4 fimbriae of enterotoxigenic Escherichia coli (ETEC).

Science.gov (United States)

Xia, Pengpeng; Zou, Yajie; Wang, Yiting; Song, Yujie; Liu, Wei; Francis, David H; Zhu, Guoqiang

2015-06-01

Infection with F4(+) enterotoxigenic Escherichia coli (ETEC) responsible for diarrhea in neonatal and post-weaned piglets leads to great economic losses in the swine industry. These pathogenic bacteria express either of three fimbrial variants F4ab, F4ac, and F4ad, which have long been known for their importance in host infection and initiating protective immune responses. The initial step in infection for the bacterium is to adhere to host enterocytes through fimbriae-mediated recognition of receptors on the host cell surface. A number of receptors for ETEC F4 have now been described and characterized, but their functions are still poorly understood. The current review summarizes the latest research addressing the characteristics of F4 fimbriae receptors and the interactions of F4 fimbriae and their receptors on host cells. These include observations that as follows: (1) FaeG mediates the binding activities of F4 and is an essential component of the F4 fimbriae, (2) the F4 fimbrial receptor gene is located in a region of chromosome 13, (3) the biochemical properties of F4 fimbrial receptors that form the binding site of the bacterium are now recognized, and (4) specific receptors confer susceptibility/resistance to ETEC F4 infection in pigs. Characterizing the host-pathogen interaction will be crucial to understand the pathogenicity of the bacteria, provide insights into receptor activation of the innate immune system, and develop therapeutic strategies to prevent this illness.

An evolutionary conserved region (ECR in the human dopamine receptor D4 gene supports reporter gene expression in primary cultures derived from the rat cortex

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Haddley Kate

2011-05-01

Full Text Available Abstract Background Detecting functional variants contributing to diversity of behaviour is crucial for dissecting genetics of complex behaviours. At a molecular level, characterisation of variation in exons has been studied as they are easily identified in the current genome annotation although the functional consequences are less well understood; however, it has been difficult to prioritise regions of non-coding DNA in which genetic variation could also have significant functional consequences. Comparison of multiple vertebrate genomes has allowed the identification of non-coding evolutionary conserved regions (ECRs, in which the degree of conservation can be comparable with exonic regions suggesting functional significance. Results We identified ECRs at the dopamine receptor D4 gene locus, an important gene for human behaviours. The most conserved non-coding ECR (D4ECR1 supported high reporter gene expression in primary cultures derived from neonate rat frontal cortex. Computer aided analysis of the sequence of the D4ECR1 indicated the potential transcription factors that could modulate its function. D4ECR1 contained multiple consensus sequences for binding the transcription factor Sp1, a factor previously implicated in DRD4 expression. Co-transfection experiments demonstrated that overexpression of Sp1 significantly decreased the activity of the D4ECR1 in vitro. Conclusion Bioinformatic analysis complemented by functional analysis of the DRD4 gene locus has identified a a strong enhancer that functions in neurons and b a transcription factor that may modulate the function of that enhancer.

Integrated olfactory receptor and microarray gene expression databases

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Crasto Chiquito J

2007-06-01

Full Text Available Abstract Background Gene expression patterns of olfactory receptors (ORs are an important component of the signal encoding mechanism in the olfactory system since they determine the interactions between odorant ligands and sensory neurons. We have developed the Olfactory Receptor Microarray Database (ORMD to house OR gene expression data. ORMD is integrated with the Olfactory Receptor Database (ORDB, which is a key repository of OR gene information. Both databases aim to aid experimental research related to olfaction. Description ORMD is a Web-accessible database that provides a secure data repository for OR microarray experiments. It contains both publicly available and private data; accessing the latter requires authenticated login. The ORMD is designed to allow users to not only deposit gene expression data but also manage their projects/experiments. For example, contributors can choose whether to make their datasets public. For each experiment, users can download the raw data files and view and export the gene expression data. For each OR gene being probed in a microarray experiment, a hyperlink to that gene in ORDB provides access to genomic and proteomic information related to the corresponding olfactory receptor. Individual ORs archived in ORDB are also linked to ORMD, allowing users access to the related microarray gene expression data. Conclusion ORMD serves as a data repository and project management system. It facilitates the study of microarray experiments of gene expression in the olfactory system. In conjunction with ORDB, ORMD integrates gene expression data with the genomic and functional data of ORs, and is thus a useful resource for both olfactory researchers and the public.

Activation of temperature-sensitive TRPV1-like receptors in ARC POMC neurons reduces food intake.

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Jae Hoon Jeong

2018-04-01

Full Text Available Proopiomelanocortin (POMC neurons in the arcuate nucleus of the hypothalamus (ARC respond to numerous hormonal and neural signals, resulting in changes in food intake. Here, we demonstrate that ARC POMC neurons express capsaicin-sensitive transient receptor potential vanilloid 1 receptor (TRPV1-like receptors. To show expression of TRPV1-like receptors in ARC POMC neurons, we use single-cell reverse transcription-polymerase chain reaction (RT-PCR, immunohistochemistry, electrophysiology, TRPV1 knock-out (KO, and TRPV1-Cre knock-in mice. A small elevation of temperature in the physiological range is enough to depolarize ARC POMC neurons. This depolarization is blocked by the TRPV1 receptor antagonist and by Trpv1 gene knockdown. Capsaicin-induced activation reduces food intake that is abolished by a melanocortin receptor antagonist. To selectively stimulate TRPV1-like receptor-expressing ARC POMC neurons in the ARC, we generate an adeno-associated virus serotype 5 (AAV5 carrying a Cre-dependent channelrhodopsin-2 (ChR2-enhanced yellow fluorescent protein (eYFP expression cassette under the control of the two neuronal POMC enhancers (nPEs. Optogenetic stimulation of TRPV1-like receptor-expressing POMC neurons decreases food intake. Hypothalamic temperature is rapidly elevated and reaches to approximately 39 °C during treadmill running. This elevation is associated with a reduction in food intake. Knockdown of the Trpv1 gene exclusively in ARC POMC neurons blocks the feeding inhibition produced by increased hypothalamic temperature. Taken together, our findings identify a melanocortinergic circuit that links acute elevations in hypothalamic temperature with acute reductions in food intake.

Polymorphism in interleukin-7 receptor α gene is associated with faster CD4 T-cell recovery after initiation of combination antiretroviral therapy

DEFF Research Database (Denmark)

Hartling, Hans J; Thørner, Lise W; Erikstrup, Christian

2014-01-01

OBJECTIVES: To investigate single-nucleotide polymorphisms (SNPs) in the gene encoding interleukin-7 receptor α (IL7RA) as predictors for CD4⁺ T-cell change after initiation of combination antiretroviral therapy (cART) in HIV-infected whites. DESIGN: SNPs in IL7RA were determined in the Danish HIV...

Melanocortin peptides inhibit production of proinflammatory cytokines and nitric oxide by activated microglia.

Science.gov (United States)

Delgado, R; Carlin, A; Airaghi, L; Demitri, M T; Meda, L; Galimberti, D; Baron, P; Lipton, J M; Catania, A

1998-06-01

Inflammatory processes contribute to neurodegenerative disease, stroke, encephalitis, and other central nervous system (CNS) disorders. Activated microglia are a source of cytokines and other inflammatory agents within the CNS and it is therefore important to control glial function in order to preserve neural cells. Melanocortin peptides are pro-opiomelanocortin-derived amino acid sequences that include alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH). These peptides have potent and broad anti-inflammatory effects. We tested effects of alpha-MSH (1-13), alpha-MSH (11-13), and ACTH (1-24) on production of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and nitric oxide (NO) in a cultured murine microglial cell line (N9) stimulated with lipopolysaccharide (LPS) plus interferon gamma (IFN-gamma). Melanocortin peptides inhibited production of these cytokines and NO in a concentration-related fashion, probably by increasing intracellular cAMP. When stimulated with LPS + IFN-gamma, microglia increased release of alpha-MSH. Production of TNF-alpha, IL-6, and NO was greater in activated microglia after innmunoneutralization of endogenous alpha-MSH. The results suggest that alpha-MSH is an autocrine factor in microglia. Because melanocortin peptides inhibit production of pro-inflammatory mediators by activated microglia they might be useful in treatment of inflammatory/degenerative brain disorders.

Genetic variation at Exon2 of TLR4 gene and its association with ...

African Journals Online (AJOL)

This study was conducted to analyze the polymorphisms of chicken Toll-like receptors 4(TLR4) gene and aimed to provide a theoretical foundation for a further research on correlation between chicken TLR4 gene and disease resistance. Genetic variations at exon 2 of TLR4 gene in 14 chicken breeds and the red jungle ...

Chronic Lymphocytic Leukemia with Mutated IGHV4-34 Receptors

DEFF Research Database (Denmark)

Xochelli, Aliki; Baliakas, Panagiotis; Kavakiotis, Ioannis

2017-01-01

Purpose: We sought to investigate whether B cell receptor immunoglobulin (BcR IG) stereotypy is associated with particular clinicobiological features among chronic lymphocytic leukemia (CLL) patients expressing mutated BcR IG (M-CLL) encoded by the IGHV4-34 gene, and also ascertain whether...

Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

International Nuclear Information System (INIS)

Kojima, Hiroyuki; Takeda, Yukimasa; Muromoto, Ryuta; Takahashi, Miki; Hirao, Toru; Takeuchi, Shinji; Jetten, Anton M.; Matsuda, Tadashi

2015-01-01

Highlights: • Nuclear receptors, RORα and RORγ, are key regulators of Th17 cell differentiation. • Isoflavones have RORα/γ agonistic activities. • Isoflavones enhance the interaction of RORα/γ with co-activator. • These compounds enhance the expression of Il17a mRNA in mouse EL4 cells. • Dietary isoflavones can act as modulators of Il17a expression via RORα/γ. - Abstract: The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. In this study, we investigated the effects of isoflavones on RORα/γ activity and the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In doxycycline-inducible CHO stable cell lines, we found that four isoflavones, biochanin A (BA), genistein, formononetin, and daidzein, enhanced RORα- or RORγ-mediated transcriptional activity in a dose-dependent manner. In an activation assay of the Il17a promoter using Jurkat cells, these compounds enhanced the RORα- or RORγ-mediated activation of the Il17a promoter at concentrations of 1 × 10 −6 M to 1 × 10 −5 M. In mammalian two-hybrid assays, the four isoflavones enhanced the interaction between the RORα- or RORγ-ligand binding domain and the co-activator LXXLL peptide in a dose-dependent manner. In addition, these isoflavones potently enhanced Il17a mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin, but showed slight enhancement of Il17a gene expression in RORα/γ-knockdown EL4 cells. Immunoprecipitation and immunoblotting assays also revealed that BA enhanced the interaction between RORγt and SRC-1, which is a co-activator for nuclear receptors. Taken together, these results suggest that the isoflavones have the ability to enhance IL-17 gene expression by stabilizing the interactions between RORα/γ and co-activators. This also

Tacrolimus increases Nox4 expression in human renal fibroblasts and induces fibrosis-related genes by aberrant TGF-beta receptor signalling.

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Georg Kern

Full Text Available Chronic nephrotoxicity of immunosuppressives is one of the main limiting factors in the long-term outcome of kidney transplants, leading to tissue fibrosis and ultimate organ failure. The cytokine TGF-β is considered a key factor in this process. In the human renal fibroblast cell line TK-173, the macrolide calcineurin inhibitor tacrolimus (FK-506 induced TGF-β-like effects, manifested by increased expression of NAD(PH-oxidase 4 (Nox4, transgelin, tropomyosin 1, and procollagen α1(V mRNA after three days. The macrolide mTOR inhibitor rapamycin had similar effects, while cyclosporine A did not induce fibrose-related genes. Concentration dependence curves were sigmoid, where mRNA expression was induced already at low nanomolar levels of tacrolimus, and reached saturation at 100-300 nM. The effects were independent of extracellular TGF-β as confirmed by the use of neutralizing antibodies, and thus most likely caused by aberrant TGF-β receptor signaling, where binding of tacrolimus to the regulatory FKBP12 protein results in a "leaky" TGF-β receptor. The myofibroblast marker α-smooth muscle actin was neither induced by tacrolimus nor by TGF-β1, indicating an incomplete activation of TK-173 fibroblasts under culture conditions. Tacrolimus- and TGF-β1-induced Nox4 protein upregulation was confirmed by Western blotting, and was accompanied by a rise in intracellular H2O2 concentration. Si-RNA mediated knock-down of Nox4 expression prevented up-regulation of procollagen α1(V mRNA in tacrolimus-treated cells, but induced procollagen α1(V expression in control cells. Nox4 knock-down had no significant effect on the other genes tested. TGF-β is a key molecule in fibrosis, and the constant activation of aberrant receptor signaling by tacrolimus might contribute to the long-term development of interstitial kidney fibrosis in immunosuppressed patients. Nox4 levels possibly play a regulatory role in these processes.

Melanin-concentrating hormone and its receptor are expressed and functional in human skin.

Science.gov (United States)

Hoogduijn, Martin J; Ancans, Janis; Suzuki, Itaru; Estdale, Siân; Thody, Anthony J

2002-08-23

In this study, we have demonstrated the presence of melanin-concentrating hormone (MCH) and melanin-concentrating hormone receptor (MCHR1) transcripts in human skin. Sequence analysis confirmed that the transcripts of both genes were identical to those previously found in human brain. In culture, endothelial cells showed pro-MCH expression whereas no signal was found in keratinocytes, melanocytes, and fibroblasts. MCHR1 expression was restricted to melanocytes and melanoma cells. Stimulation of cultured human melanocytes with MCH reduced the alpha-MSH-induced increase in cAMP production. Furthermore, the melanogenic actions of alpha-MSH were inhibited by MCH. We propose that the MCH/MCHR1 signalling system is present in human skin and may have a role with the melanocortins in regulating the melanocyte.

Genomic organization, annotation, and ligand-receptor inferences of chicken chemokines and chemokine receptor genes based on comparative genomics

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Sze Sing-Hoi

2005-03-01

Full Text Available Abstract Background Chemokines and their receptors play important roles in host defense, organogenesis, hematopoiesis, and neuronal communication. Forty-two chemokines and 19 cognate receptors have been found in the human genome. Prior to this report, only 11 chicken chemokines and 7 receptors had been reported. The objectives of this study were to systematically identify chicken chemokines and their cognate receptor genes in the chicken genome and to annotate these genes and ligand-receptor binding by a comparative genomics approach. Results Twenty-three chemokine and 14 chemokine receptor genes were identified in the chicken genome. All of the chicken chemokines contained a conserved CC, CXC, CX3C, or XC motif, whereas all the chemokine receptors had seven conserved transmembrane helices, four extracellular domains with a conserved cysteine, and a conserved DRYLAIV sequence in the second intracellular domain. The number of coding exons in these genes and the syntenies are highly conserved between human, mouse, and chicken although the amino acid sequence homologies are generally low between mammalian and chicken chemokines. Chicken genes were named with the systematic nomenclature used in humans and mice based on phylogeny, synteny, and sequence homology. Conclusion The independent nomenclature of chicken chemokines and chemokine receptors suggests that the chicken may have ligand-receptor pairings similar to mammals. All identified chicken chemokines and their cognate receptors were identified in the chicken genome except CCR9, whose ligand was not identified in this study. The organization of these genes suggests that there were a substantial number of these genes present before divergence between aves and mammals and more gene duplications of CC, CXC, CCR, and CXCR subfamilies in mammals than in aves after the divergence.

[Association of polymorphisms in toll-like receptor genes with atopic dermatitis in the Republic of Bashkortostan].

Science.gov (United States)

Gimalova, G F; Karunas, A S; Fedorova, Iu Iu; Gumennaia, É R; Levasheva, S V; Khismatullina, Z R; Prans, E; Koks, S; Étkina, É I; Khusnutdinova, É K

2014-01-01

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease developing as a result of the interaction between genetic predisposition and environmental factors. Considerable role in allergic diseases development is played by polymorphisms of genes of pattern-recognition receptors (PRR) which are capable of recognizing conservative standard molecular structures (patterns) unique for large pathogen groups. In this study polymorphic variants of PRR genes--Toll-like receptors (TLR1, TLR2, TLR4, TLR5, TLR6, TLR9, TLR10), NOD-like receptors (NOD1, NOD2), lipopolysaccharide receptor CD14 gene, and C11orf30 and LRRC32 genes, located in 11q13.5 region, have been investigated in AD patients and control subjects from the Republic of Bashkortostan. An association of TLR1 (rs5743571 and rs5743604), TLR6 (rs5743794) and TLR10 (rs11466617) with AD was found. Our results confirm an important role of the innate immune system in the pathogenesis of AD and the significance of polymorphisms within the Toll-like receptor 2 subfamily genes in AD development.

The structure of the human interferon alpha/beta receptor gene.

Science.gov (United States)

Lutfalla, G; Gardiner, K; Proudhon, D; Vielh, E; Uzé, G

1992-02-05

Using the cDNA coding for the human interferon alpha/beta receptor (IFNAR), the IFNAR gene has been physically mapped relative to the other loci of the chromosome 21q22.1 region. 32,906 base pairs covering the IFNAR gene have been cloned and sequenced. Primer extension and solution hybridization-ribonuclease protection have been used to determine that the transcription of the gene is initiated in a broad region of 20 base pairs. Some aspects of the polymorphism of the gene, including noncoding sequences, have been analyzed; some are allelic differences in the coding sequence that induce amino acid variations in the resulting protein. The exon structure of the IFNAR gene and of that of the available genes for the receptors of the cytokine/growth hormone/prolactin/interferon receptor family have been compared with the predictions for the secondary structure of those receptors. From this analysis, we postulate a common origin and propose an hypothesis for the divergence from the immunoglobulin superfamily.

No evidence for a major gene effect of the dopamine D{sub 4} receptor gene in the susceptibility to Gilles de la Tourette Syndrome in five Canadian families

Energy Technology Data Exchange (ETDEWEB)

Barr, C.L.; Wigg, K.G.; Tsui, Lap-Chee [Univ. of Toronto, Ontario (Canada)] [and others

1996-05-31

Gilles de la Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by both motor and vocal tics affecting approximately 1/10,000 females and 1/2000 males. Because of the success of neuroleptics and other agents interacting with the dopaminergic system in the suppression of tics, a defect in the dopamine system has been hypothesized in the etiology of TS. In this paper we test the hypothesis that the dopamine D{sub 4} receptor (DRD44) is linked to the genetic susceptibility to TS in five families. We tested three polymorphisms in the DRD4 gene and a polymorphism in the closely linked locus, tyrosine hydroxylase (TH). We found no evidence for linkage of DRD4 or TH to TS using an autosomal dominant model with reduced penetrance or using non-parametric methods. The presence of a mutation that results in a truncated non-functional D{sub 4} receptor protein was also tested for, but was not observed in these families. 36 refs., 1 tab.

Hormonal control of spermatogenesis: expression of FSJH receptor and androgen receptor genes

NARCIS (Netherlands)

L.J. Blok (Leen)

1992-01-01

textabstractFSH and testosterone are the main hormonal regulators of spermatogenesis. The actions of androgens and FSH are mediated by their respective receptors. Receptor gene expression (mRNA and protein). is an important determinant of hormone action. Biochemical aspects of the regulation of

Glucocorticoid receptor gene polymorphism and juvenile idiopathic arthritis

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Scheplyagina Larisa A

2011-01-01

Full Text Available Abstract Background The glucocorticoid receptor gene (NR3C1 has been suggested as a candidate gene affecting juvenile idiopathic arthritis (JIA course and prognosis. The purpose of this study is to investigate the glucocorticoid receptor gene BclI polymorphism (rs41423247 in JIA patients, the gene's role in susceptibility to juvenile idiopathic arthritis, and its associations with JIA activity, course and bone mineralization. Methods One hundred twenty-two Caucasian children with JIA and 143 healthy ethnically matched controls were studied. We checked markers of clinical and laboratory activity: morning stiffness, Ritchie Articular Index (RAI, swollen joint count (SJC, tender joint count (TJC, physician's visual analog scale (VAS, hemoglobin level (Hb, leukocyte count (L, platelet count (Pl, Westergren erythrocyte sedimentation rate (ESR, C-reactive protein (CRP, albumin, DAS and DAS28. Bone mineralization was measured by dual-energy X-ray absorptiometry (DXA of lumbar spine L1-L4. Assessments of bone metabolism included osteocalcin, C-terminal telopeptide (CTT, parathyroid hormone (PTH, total and ionized calcium, inorganic phosphate and total alkaline phosphatase (TAP. BclI polymorphism was genotyped by polymerase chain reaction restriction fragment length polymorphism. Results No association was observed between glucocorticoid receptor gene polymorphism and the presence or absence of JIA. In girls with JIA, the presence of the G allele was associated with an unfavorable arthritis course, a younger age of onset of arthritis (p = 0.0017, and higher inflammatory activity. The higher inflammatory activity was demonstrated by the following: increased time of morning stiffness (p = 0.02, VAS (p = 0.014, RAI (p = 0.048, DAS (p = 0.035, DAS28 (p = 0.05, Pl (p = 0.003, L (p = 0.046, CRP (p = 0.01. In addition, these patients had bone metabolism disturbances as follows: decreased BA (p = 0.0001, BMC (p = 0.00007, BMD (0.005 and Z score (p = 0.002; and

Dopamine Receptor Genes Modulate Associative Memory in Old Age.

Science.gov (United States)

Papenberg, Goran; Becker, Nina; Ferencz, Beata; Naveh-Benjamin, Moshe; Laukka, Erika J; Bäckman, Lars; Brehmer, Yvonne

2017-02-01

Previous research shows that associative memory declines more than item memory in aging. Although the underlying mechanisms of this selective impairment remain poorly understood, animal and human data suggest that dopaminergic modulation may be particularly relevant for associative binding. We investigated the influence of dopamine (DA) receptor genes on item and associative memory in a population-based sample of older adults (n = 525, aged 60 years), assessed with a face-scene item associative memory task. The effects of single-nucleotide polymorphisms of DA D1 (DRD1; rs4532), D2 (DRD2/ANKK1/Taq1A; rs1800497), and D3 (DRD3/Ser9Gly; rs6280) receptor genes were examined and combined into a single genetic score. Individuals carrying more beneficial alleles, presumably associated with higher DA receptor efficacy (DRD1 C allele; DRD2 A2 allele; DRD3 T allele), performed better on associative memory than persons with less beneficial genotypes. There were no effects of these genes on item memory or other cognitive measures, such as working memory, executive functioning, fluency, and perceptual speed, indicating a selective association between DA genes and associative memory. By contrast, genetic risk for Alzheimer disease (AD) was associated with worse item and associative memory, indicating adverse effects of APOE ε4 and a genetic risk score for AD (PICALM, BIN1, CLU) on episodic memory in general. Taken together, our results suggest that DA may be particularly important for associative memory, whereas AD-related genetic variations may influence overall episodic memory in older adults without dementia.

Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

Science.gov (United States)

Kojima, Hiroyuki; Takeda, Yukimasa; Muromoto, Ryuta; Takahashi, Miki; Hirao, Toru; Takeuchi, Shinji; Jetten, Anton M.; Matsuda, Tadashi

2018-01-01

The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. In this study, we investigated the effects of isoflavones on RORα/γ activity and the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In doxycycline-inducible CHO stable cell lines, we found that four isoflavones, biochanin A (BA), genistein, formononetin, and daidzein, enhanced RORα- or RORγ-mediated transcriptional activity in a dose-dependent manner. In an activation assay of the Il17a promoter using Jurkat cells, these compounds enhanced the RORα- or RORγ-mediated activation of the Il17a promoter at concentrations of 1 × 10−6 M to 1 × 10−5 M. In mammalian two-hybrid assays, the four isoflavones enhanced the interaction between the RORα- or RORγ-ligand binding domain and the co-activator LXXLL peptide in a dose-dependent manner. In addition, these isoflavones potently enhanced Il17a mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin, but showed slight enhancement of Il17a gene expression in RORα/γ-knockdown EL4 cells. Immunoprecipitation and immunoblotting assays also revealed that BA enhanced the interaction between RORγt and SRC-1, which is a co-activator for nuclear receptors. Taken together, these results suggest that the isoflavones have the ability to enhance IL-17 gene expression by stabilizing the interactions between RORα/γ and co-activators. This also provides the first evidence that dietary chemicals can enhance IL-17 gene expression in immune cells. PMID:25583575

The interleukin-4 receptor: signal transduction by a hematopoietin receptor.

Science.gov (United States)

Keegan, A D; Pierce, J H

1994-02-01

Over the last several years, the receptors for numerous cytokines have been molecularly characterized. Analysis of their amino acid sequences shows that some of these receptors bear certain motifs in their extracellular domains that define a family of receptors called the Hematopoietin receptor superfamily. Significant advances in characterizing the structure, function, and mechanisms of signal transduction have been made for several members of this family. The purpose of this review is to discuss the recent advances made for one of the family members, the interleukin (IL) 4 receptor. Other receptor systems have recently been reviewed elsewhere. The IL-4 receptor consists of, at the minimum, the cloned 140 kDa IL-4-binding chain with the potential for associating with other chains. The IL-4 receptor transduces its signal by activating a tyrosine kinase that phosphorylates cellular substrates, including the receptor itself, and the 170 kDa substrate called 4PS. Phosphorylated 4PS interacts with the SH2 domain of the enzyme PI-3'-kinase and increases its enzymatic activity. These early events in the IL-4 receptor initiated signaling pathway may trigger a series of signals that will ultimately lead to an IL-4 specific biologic outcome.

Gene Transfer and Molecular Cloning of the Human NGF Receptor

Science.gov (United States)

Chao, Moses V.; Bothwell, Mark A.; Ross, Alonzo H.; Koprowski, Hilary; Lanahan, Anthony A.; Buck, C. Randall; Sehgal, Amita

1986-04-01

Nerve growth factor (NGF) and its receptor are important in the development of cells derived from the neural crest. Mouse L cell transformants have been generated that stably express the human NGF receptor gene transfer with total human DNA. Affinity cross-linking, metabolic labeling and immunoprecipitation, and equilibrium binding with 125I-labeled NGF revealed that this NGF receptor had the same size and binding characteristics as the receptor from human melanoma cells and rat PC12 cells. The sequences encoding the NGF receptor were molecularly cloned using the human Alu repetitive sequence as a probe. A cosmid clone that contained the human NGF receptor gene allowed efficient transfection and expression of the receptor.

No substantial changes in estrogen receptor and estrogen-related receptor orthologue gene transcription in Marisa cornuarietis exposed to estrogenic chemicals.

Science.gov (United States)

Bannister, Richard; Beresford, Nicola; Granger, David W; Pounds, Nadine A; Rand-Weaver, Mariann; White, Roger; Jobling, Susan; Routledge, Edwin J

2013-09-15

Estrogen receptor orthologues in molluscs may be targets for endocrine disruptors, although mechanistic evidence is lacking. Molluscs are reported to be highly susceptible to effects caused by very low concentrations of environmental estrogens which, if substantiated, would have a major impact on the risk assessment of many chemicals. The present paper describes the most thorough evaluation to-date of the susceptibility of Marisa cornuarietis ER and ERR gene transcription to modulation by vertebrate estrogens in vivo and in vitro. We investigated the effects of estradiol-17β and 4-tert-Octylphenol exposure on in vivo estrogen receptor (ER) and estrogen-related receptor (ERR) gene transcription in the reproductive and neural tissues of the gastropod snail M. cornuarietis over a 12-week period. There was no significant effect (p>0.05) of treatment on gene transcription levels between exposed and non-exposed snails. Absence of a direct interaction of estradiol-17β and 4-tert-Octylphenol with mollusc ER and ERR protein was also supported by in vitro studies in transfected HEK-293 cells. Additional in vitro studies with a selection of other potential ligands (including methyl-testosterone, 17α-ethinylestradiol, 4-hydroxytamoxifen, diethylstilbestrol, cyproterone acetate and ICI182780) showed no interaction when tested using this assay. In repeated in vitro tests, however, genistein (with mcER-like) and bisphenol-A (with mcERR) increased reporter gene expression at high concentrations only (>10(-6)M for Gen and >10(-5)M for BPA, respectively). Like vertebrate estrogen receptors, the mollusc ER protein bound to the consensus vertebrate estrogen-response element (ERE). Together, these data provide no substantial evidence that mcER-like and mcERR activation and transcript levels in tissues are modulated by the vertebrate estrogen estradiol-17β or 4-tert-Octylphenol in vivo, or that other ligands of vertebrate ERs and ERRs (with the possible exception of genistein and

Alterations in the hypothalamic melanocortin pathway in amyotrophic lateral sclerosis.

Science.gov (United States)

Vercruysse, Pauline; Sinniger, Jérôme; El Oussini, Hajer; Scekic-Zahirovic, Jelena; Dieterlé, Stéphane; Dengler, Reinhard; Meyer, Thomas; Zierz, Stephan; Kassubek, Jan; Fischer, Wilhelm; Dreyhaupt, Jens; Grehl, Torsten; Hermann, Andreas; Grosskreutz, Julian; Witting, Anke; Van Den Bosch, Ludo; Spreux-Varoquaux, Odile; Ludolph, Albert C; Dupuis, Luc

2016-04-01

Amyotrophic lateral sclerosis, the most common adult-onset motor neuron disease, leads to death within 3 to 5 years after onset. Beyond progressive motor impairment, patients with amyotrophic lateral sclerosis suffer from major defects in energy metabolism, such as weight loss, which are well correlated with survival. Indeed, nutritional intervention targeting weight loss might improve survival of patients. However, the neural mechanisms underlying metabolic impairment in patients with amyotrophic lateral sclerosis remain elusive, in particular due to the lack of longitudinal studies. Here we took advantage of samples collected during the clinical trial of pioglitazone (GERP-ALS), and characterized longitudinally energy metabolism of patients with amyotrophic lateral sclerosis in response to pioglitazone, a drug with well-characterized metabolic effects. As expected, pioglitazone decreased glycaemia, decreased liver enzymes and increased circulating adiponectin in patients with amyotrophic lateral sclerosis, showing its efficacy in the periphery. However, pioglitazone did not increase body weight of patients with amyotrophic lateral sclerosis independently of bulbar involvement. As pioglitazone increases body weight through a direct inhibition of the hypothalamic melanocortin system, we studied hypothalamic neurons producing proopiomelanocortin (POMC) and the endogenous melanocortin inhibitor agouti-related peptide (AGRP), in mice expressing amyotrophic lateral sclerosis-linked mutant SOD1(G86R). We observed lower Pomc but higher Agrp mRNA levels in the hypothalamus of presymptomatic SOD1(G86R) mice. Consistently, numbers of POMC-positive neurons were decreased, whereas AGRP fibre density was elevated in the hypothalamic arcuate nucleus of SOD1(G86R) mice. Consistent with a defect in the hypothalamic melanocortin system, food intake after short term fasting was increased in SOD1(G86R) mice. Importantly, these findings were replicated in two other amyotrophic

Characteristics of the mouse genomic histamine H1 receptor gene

Energy Technology Data Exchange (ETDEWEB)

Inoue, Isao; Taniuchi, Ichiro; Kitamura, Daisuke [Kyushu Univ., Fukuoka (Japan)] [and others

1996-08-15

We report here the molecular cloning of a mouse histamine H1 receptor gene. The protein deduced from the nucleotide sequence is composed of 488 amino acid residues with characteristic properties of GTP binding protein-coupled receptors. Our results suggest that the mouse histamine H1 receptor gene is a single locus, and no related sequences were detected. Interspecific backcross analysis indicated that the mouse histamine H1 receptor gene (Hrh1) is located in the central region of mouse Chromosome 6 linked to microphthalmia (Mitfmi), ras-related fibrosarcoma oncogene 1 (Raf1), and ret proto-oncogene (Ret) in a region of homology with human chromosome 3p. 12 refs., 3 figs.

Bioinformatics analysis of breast cancer bone metastasis related gene-CXCR4

Institute of Scientific and Technical Information of China (English)

Heng-Wei Zhang; Xian-Fu Sun; Ya-Ning He; Jun-Tao Li; Xu-Hui Guo; Hui Liu

2013-01-01

Objective: To analyze breast cancer bone metastasis related gene-CXCR4. Methods: This research screened breast cancer bone metastasis related genes by high-flux gene chip. Results:It was found that the expressions of 396 genes were different including 165 up-regulations and 231 down-regulations. The expression of chemokine receptor CXCR4 was obviously up-regulated in the tissue with breast cancer bone metastasis. Compared with the tissue without bone metastasis, there was significant difference, which indicated that CXCR4 played a vital role in breast cancer bone metastasis. Conclusions: The bioinformatics analysis of CXCR4 can provide a certain basis for the occurrence and diagnosis of breast cancer bone metastasis, target gene therapy and evaluation of prognosis.

Pseudogenization of a sweet-receptor gene accounts for cats' indifference toward sugar.

Directory of Open Access Journals (Sweden)

Xia Li

2005-07-01

Full Text Available Although domestic cats (Felis silvestris catus possess an otherwise functional sense of taste, they, unlike most mammals, do not prefer and may be unable to detect the sweetness of sugars. One possible explanation for this behavior is that cats lack the sensory system to taste sugars and therefore are indifferent to them. Drawing on work in mice, demonstrating that alleles of sweet-receptor genes predict low sugar intake, we examined the possibility that genes involved in the initial transduction of sweet perception might account for the indifference to sweet-tasting foods by cats. We characterized the sweet-receptor genes of domestic cats as well as those of other members of the Felidae family of obligate carnivores, tiger and cheetah. Because the mammalian sweet-taste receptor is formed by the dimerization of two proteins (T1R2 and T1R3; gene symbols Tas1r2 and Tas1r3, we identified and sequenced both genes in the cat by screening a feline genomic BAC library and by performing PCR with degenerate primers on cat genomic DNA. Gene expression was assessed by RT-PCR of taste tissue, in situ hybridization, and immunohistochemistry. The cat Tas1r3 gene shows high sequence similarity with functional Tas1r3 genes of other species. Message from Tas1r3 was detected by RT-PCR of taste tissue. In situ hybridization and immunohistochemical studies demonstrate that Tas1r3 is expressed, as expected, in taste buds. However, the cat Tas1r2 gene shows a 247-base pair microdeletion in exon 3 and stop codons in exons 4 and 6. There was no evidence of detectable mRNA from cat Tas1r2 by RT-PCR or in situ hybridization, and no evidence of protein expression by immunohistochemistry. Tas1r2 in tiger and cheetah and in six healthy adult domestic cats all show the similar deletion and stop codons. We conclude that cat Tas1r3 is an apparently functional and expressed receptor but that cat Tas1r2 is an unexpressed pseudogene. A functional sweet-taste receptor heteromer

Pseudogenization of a Sweet-Receptor Gene Accounts for Cats' Indifference toward Sugar.

Directory of Open Access Journals (Sweden)

2005-07-01

Full Text Available Although domestic cats (Felis silvestris catus possess an otherwise functional sense of taste, they, unlike most mammals, do not prefer and may be unable to detect the sweetness of sugars. One possible explanation for this behavior is that cats lack the sensory system to taste sugars and therefore are indifferent to them. Drawing on work in mice, demonstrating that alleles of sweet-receptor genes predict low sugar intake, we examined the possibility that genes involved in the initial transduction of sweet perception might account for the indifference to sweet-tasting foods by cats. We characterized the sweet-receptor genes of domestic cats as well as those of other members of the Felidae family of obligate carnivores, tiger and cheetah. Because the mammalian sweet-taste receptor is formed by the dimerization of two proteins (T1R2 and T1R3; gene symbols Tas1r2 and Tas1r3, we identified and sequenced both genes in the cat by screening a feline genomic BAC library and by performing PCR with degenerate primers on cat genomic DNA. Gene expression was assessed by RT-PCR of taste tissue, in situ hybridization, and immunohistochemistry. The cat Tas1r3 gene shows high sequence similarity with functional Tas1r3 genes of other species. Message from Tas1r3 was detected by RT-PCR of taste tissue. In situ hybridization and immunohistochemical studies demonstrate that Tas1r3 is expressed, as expected, in taste buds. However, the cat Tas1r2 gene shows a 247-base pair microdeletion in exon 3 and stop codons in exons 4 and 6. There was no evidence of detectable mRNA from cat Tas1r2 by RT-PCR or in situ hybridization, and no evidence of protein expression by immunohistochemistry. Tas1r2 in tiger and cheetah and in six healthy adult domestic cats all show the similar deletion and stop codons. We conclude that cat Tas1r3 is an apparently functional and expressed receptor but that cat Tas1r2 is an unexpressed pseudogene. A functional sweet-taste receptor heteromer

Effect of Nelumbo nucifera Petal Extracts on Lipase, Adipogenesis, Adipolysis, and Central Receptors of Obesity

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Chandrasekaran Chinampudur Velusami

2013-01-01

Full Text Available N. nucifera is one among the important medicinal plants assessed for its antiobesity action in various preclinical models. The present study was aimed at investigating the antiobesity effect of methanol and successive water extracts of petals of N. nucifera by studying its effect on adipogenesis, adipolysis, lipase, serotonin (5-HT2C, cannabinoid (CNR2, melanocyte concentrating hormone (MCHR1, and melanocortin (MC4R receptors. Both methanol and successive water extracts of N. nucifera petals had an effect on inhibition of lipid storage in adipocytes and on increasing lipolysis. N. nucifera petal methanol extract exhibited the concentration-dependent inhibitory effect on lipase activity with an IC50 value of 47 µg/mL. N. nucifera petal extracts showed evident agonist and antagonist activity towards 5-HT2C and CNR2 receptors, respectively, while it showed no effect towards MCHR1 and MC4R receptors. Overall, methanol extract of N. nucifera petals showed better activity than successive water extract.

Structure and expression of the human and mouse T4 genes

International Nuclear Information System (INIS)

Maddon, P.J.; Molineaux, S.M.; Maddon, D.F.; Zimmerman, K.A.; Godfrey, M.; Alt, F.W.; Chess, L.; Axel, R.

1987-01-01

The T4 molecule may serve as a T-cell receptor recognizing molecules on the surface of specific target cells and also serves as the receptor for the human immunodeficiency virus. To define the mechanisms of interaction of T4 with the surface of antigen-presenting cells as well as with human immunodeficiency virus, the authors have further analyzed the sequence, structure, and expression of the human and mouse T4 genes. T4 consists of an extracellular segment comprised of a leader sequence followed by four tandem variable-joining (VJ)-like domains, a transmembrane domain, and A cytoplasmic segment. The structural domains of the T4 protein deduced from amino acid sequence are precisely reflected in the intron-exon organization of the gene. Analysis of the expression of the T4 gene indicates that T4 RNA is expressed not only in T lymphocytes, but in B cells, macrophages, and granulocytes. T4 is also expressed in a developmentally regulated manner in specific regions of the brain. It is, therefore, possible that T4 plays a more general role in mediating cell recognition events that are not restricted to the cellular immune response

A Single Dose of LSD Does Not Alter Gene Expression of the Serotonin 2A Receptor Gene (HTR2A) or Early Growth Response Genes (EGR1-3) in Healthy Subjects

Science.gov (United States)

Dolder, Patrick C.; Grünblatt, Edna; Müller, Felix; Borgwardt, Stefan J.; Liechti, Matthias E.

2017-01-01

Rationale: Renewed interest has been seen in the use of lysergic acid diethylamide (LSD) in psychiatric research and practice. The repeated use of LSD leads to tolerance that is believed to result from serotonin (5-HT) 5-HT2A receptor downregulation. In rats, daily LSD administration for 4 days decreased frontal cortex 5-HT2A receptor binding. Additionally, a single dose of LSD acutely increased expression of the early growth response genes EGR1 and EGR2 in rat and mouse brains through 5-HT2A receptor stimulation. No human data on the effects of LSD on gene expression has been reported. Therefore, we investigated the effects of single-dose LSD administration on the expression of the 5-HT2A receptor gene (HTR2A) and EGR1-3 genes. Methods: mRNA expression levels were analyzed in whole blood as a peripheral biomarker in 15 healthy subjects before and 1.5 and 24 h after the administration of LSD (100 μg) and placebo in a randomized, double-blind, placebo-controlled, cross-over study. Results: LSD did not alter the expression of the HTR2A or EGR1-3 genes 1.5 and 24 h after administration compared with placebo. Conclusion: No changes were observed in the gene expression of LSD’s primary target receptor gene or genes that are implicated in its downstream effects. Remaining unclear is whether chronic LSD administration alters gene expression in humans. PMID:28701958

Estrogen-related receptor beta interacts with Oct4 to positively regulate Nanog gene expression

NARCIS (Netherlands)

D.L.C. van den Berg (Debbie); W. Zhang (Wensheng); A. Yates (Adam); M.P. Engelen (Erik); K. Takacs (Katalin); K. Bezstarosti (Karel); J.A.A. Demmers (Jeroen); I. Chambers (Ian); R.A. Poor (Raymond)

2008-01-01

textabstractEmbryonic stem (ES) cell self-renewal is regulated by transcription factors, including Oct4, Sox2, and Nanog. A number of additional transcriptional regulators of ES cell self-renewal have recently been identified, including the orphan nuclear receptor estrogen-related receptor beta

The urokinase receptor and its structural homologue C4.4A in human cancer

DEFF Research Database (Denmark)

Jacobsen, B; Ploug, M

2008-01-01

The urokinase-type plasminogen activator receptor (uPAR) and its structural homologue C4.4A are multidomain members of the Ly6/uPAR/alpha-neurotoxin protein domain family. Both are glycosylphosphatidylinositol-anchored membrane glycoproteins encoded by neighbouring genes located on chromosome 19q13...... that high protein expression in tumour cells of non-small cell pulmonary adenocarcinomas is associated with a particularly severe disease progression. This review will evaluate structural-functional and disease-related aspects of uPAR and C4.4A with a view to possible pharmacological targeting strategies...... in the human genome. The structural relationship between the two proteins is, however, not reflected at the functional level. Whereas uPAR has a well-established role in regulating and focalizing uPA-mediated plasminogen activation to the surface of those cells expressing the receptor, the biological function...

The Dopamine Receptor D4 Gene ("DRD4") Moderates Family Environmental Effects on ADHD

Science.gov (United States)

Martel, Michelle M.; Nikolas, Molly; Jernigan, Katherine; Friderici, Karen; Waldman, Irwin; Nigg, Joel T.

2011-01-01

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prime candidate for exploration of gene-by-environment interaction (i.e., G x E), particularly in relation to dopamine system genes, due to strong evidence that dopamine systems are dysregulated in the disorder. Using a G x E design, we examined whether the "DRD4" promoter 120-bp tandem repeat…

Up-regulation of proproliferative genes and the ligand/receptor pair placental growth factor and vascular endothelial growth factor receptor 1 in hepatitis C cirrhosis.

Science.gov (United States)

Huang, Xiao X; McCaughan, Geoffrey W; Shackel, Nicholas A; Gorrell, Mark D

2007-09-01

Cirrhosis can lead to hepatocellular carcinoma (HCC). Non-diseased liver and hepatitis C virus (HCV)-associated cirrhosis with or without HCC were compared. Proliferation pathway genes, immune response genes and oncogenes were analysed by a quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunostaining. Real-time RT-PCR showed up-regulation of genes in HCV cirrhosis including the proliferation-associated genes bone morphogenetic protein 3 (BMP3), placental growth factor 3 (PGF3), vascular endothelial growth factor receptor 1 (VEGFR1) and soluble VEGFR1, the oncogene FYN, and the immune response-associated genes toll-like receptor 9 (TLR9) and natural killer cell transcript 4 (NK4). Expressions of TLR2 and the oncogenes B-cell CLL/lymphoma 9 (BCL9) and PIM2 were decreased in HCV cirrhosis. In addition, PIM2 and TLR2 were increased in HCV cirrhosis with HCC compared with HCV cirrhosis. The ligand/receptor pair PGF and VEGFR1 was intensely expressed by the portal tract vascular endothelium. VEGFR1 was expressed in reactive biliary epithelial structures in fibrotic septum and in some stellate cells and macrophages. PGF and VEGFR1 may have an important role in the pathogenesis of the neovascular response in cirrhosis.

Dopamine receptor D4 promoter hypermethylation increases the risk of drug addiction.

Science.gov (United States)

Ji, Huihui; Xu, Xuting; Liu, Guili; Liu, Huifen; Wang, Qinwen; Shen, Wenwen; Li, Longhui; Xie, Xiaohu; Hu, Haochang; Xu, Lei; Zhou, Wenhua; Duan, Shiwei

2018-02-01

Heroin and methylamphetamine (METH) are two addictive drugs that cause serious problems for society. Dopamine receptor D4 (DRD4), a key receptor in the dopaminergic system, may facilitate the development of drug addiction. The aim of the present study was to investigate the association between the promoter methylation level of DRD4 gene and drug addiction. Bisulfite pyrosequencing technology was used to measure the methylation levels of DRD4 promoter in 60 drug addicts and 52 matched controls. Significantly higher levels of DRD4 CpG1 and CpG4 methylation were detected in METH and heroin drug addicts compared with controls (Pdrug addiction.

Aryl hydrocarbon receptor (AhR-mediated perturbations in gene expression during early stages of CD4+ T-cell differentiation

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Diana eRohlman

2012-08-01

Full Text Available Activation of the aryl hydrocarbon receptor (AhR by its prototypic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, mediates potent suppression of T-cell dependent immune responses. The suppressive effects of TCDD occur early during CD4+ T-cell differentiation in the absence of effects on proliferation and have recently been associated with the induction of AhR-dependent regulatory T-cells (Treg. Since AhR functions as a ligand-activated transcription factor, changes in gene expression induced by TCDD during the early stages of CD4+ T-cell differentiation are likely to reflect fundamental mechanisms of AhR action. A custom panel of genes associated with T-cell differentiation was used to query changes in gene expression induced by exposure to 1 nM TCDD. CD4+ T-cells from AhR+/+ and AhR-/- mice were cultured with cytokines known to polarize the differentiation of T-cells to various effector lineages. Treatment with TCDD induced expression of Cyp1a1, Cyp1b1 and Ahrr in CD4+ T-cells from AhR+/+ mice under all culture conditions, validating the presence and activation of AhR in these cells. The highest levels of AhR activation occurred under Th17 conditions at 24 hours and Tr1 conditions at 48 hours. Unexpectedly, expression levels of most genes associated with early T-cell differentiation were unaltered by AhR activation, including lineage-specific genes that drive CD4+ T-cell polarization. The major exception was AhR-dependent up-regulation of Il22 that was seen under all culture conditions. Independent of TCDD, AhR down-regulated the expression of Il17a and Rorc based on increased expression of these genes in AhR-deficient cells across culture conditions. These findings are consistent with a role for AhR in down-regulation of inflammatory immune responses and implicate IL-22 as a potential contributor to the immunosuppressive effects of TCDD.

Disseminated cysticercosis: clinical spectrum, Toll-like receptor-4 gene polymorphisms and role of albendazole: A prospective follow-up of 60 cases with a review of 56 published cases.

Science.gov (United States)

Qavi, Abdul; Garg, Ravindra Kumar; Malhotra, Hardeep Singh; Jain, Amita; Kumar, Neeraj; Malhotra, Kiran Preet; Srivastava, Pradeep Kumar; Verma, Rajesh; Sharma, Praveen Kumar

2016-09-01

In this study, we describe clinical and imaging spectrum, and the natural course of patients with disseminated cysticercosis. How albendazole affects the course of disease has also been evaluated. We assessed the Toll-like receptor-4 gene polymorphisms, to know the reason for the apparently higher prevalence of disseminated cysticercosis in India.Sixty consecutive patients with disseminated cysticercosis were enrolled. Sixty age-and-sex-matched healthy controls were also enrolled for the purpose of genetic study. Twenty patients, who gave consent, were treated with albendazole along with corticosteroids. Forty patients did not give consent for antiparasitic therapy. Assessment for Toll-like receptor-4 gene polymorphisms (Asp299Gly and Thr399Ile genes) was done. Patients were followed for 6 months. We also performed a literature search of cases published in English language using PubMed electronic database and analyzed 56 cases thus available.There was an increased risk (6.63 fold and 4.61 fold) of disseminated cysticercosis in the presence of Asp299Gly and Thr399Ile polymorphisms in Toll-like receptor-4, respectively. The allelic frequency of Gly (11% vs. 3%, P = 0.024, odds ratio [OR] = 3.52) and Ile alleles (11% vs. 2%, P = 0.009, OR = 4.738) in disseminated cysticercosis was high. Albendazole resulted in complete disappearance of all cerebral lesions in 35% (7/20) patients and reduction in lesion load in remaining 65% (13/20) patients. No significant change in number of cysticercal lesion was noted in patients who did not receive albendazole. No major adverse reaction following antiparasitic treatment was noted. Three deaths were recorded in patients who did not receive antiparasitic treatment.Of the 56 cases reported in PubMed, 33 patients received antiparasitic treatment with follow-up data available for 31 patients. Most (24) of these patients received albendazole. A significant clinical and/or imaging improvements, on follow up, were observed in 27 patients

Polymorphism in leptin receptor gene was associated with obesity in ...

African Journals Online (AJOL)

The mutation in leptin receptor (LEPR) gene causes splicing abnormality that resulted in truncated receptor, aberrant signal transduction, leptin resistance, and obesity. This study aims to determine the association of LEPR gene polymorphisms, rs1137100 and rs1137101, on phenotype and leptin level between obese and ...

The effect of melatonin from slow-release implants on basic and TLR-4-mediated gene expression of inflammatory cytokines and their receptors in the choroid plexus in ewes.

Science.gov (United States)

Kowalewska, M; Herman, A P; Szczepkowska, A; Skipor, J

2017-08-01

The present study concerns the effect of melatonin from slow-release implants on the expression of genes coding interleukin-1β (Il1B), inerleukin-6 (Il6), tumour necrosis factor α (Tnf) and their receptors: IL-1 receptor type I (Il1r1) and type II (Il1r2), IL-6 receptor (Il6r) and signal transducer (Il6st), TNFα receptor type I (Tnfrsf1a) and II (Tnfrsf1b) and retinoid-related orphan receptor α (RorA) and Rev.-erbα in the ovine choroid plexus (CP) under basal and lipopolysaccharide (LPS)-challenged conditions. Studies were performed on four groups: 1) sham-implanted and placebo-treated, 2) melatonin-implanted (Melovine, 18mg) and placebo-treated, 3) sham-implanted and LPS-treated (400ng/kg of body weight) and 4) melatonin-implanted and LPS-treated. Under basal conditions, we observed weak expression of Tnf, low expression of Il1B, Il6 and Il1r2 and intermediate expression of other cytokines receptors. LPS treatment induced (P≤0.05) expression in all cytokines and their receptors, except Il6r 3h after the administration. Melatonin attenuated (P≤0.05) LPS-induced up-regulation of Il6 but had no effect on other cytokines and their receptors and up-regulated (P≤0.05) Rev.-erbα expression under basal conditions. This indicates that melatonin from slow-release implants suppresses TLR4-mediated Il6 expression in the ovine CP via a mechanism likely involving clock genes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Peroxisome Proliferator-Activated Receptor Alpha Target Genes

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Maryam Rakhshandehroo

2010-01-01

Full Text Available The peroxisome proliferator-activated receptor alpha (PPARα is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARα serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARα binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARα governs biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARα is directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARα in lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARα target genes. The emphasis is on gene regulation by PPARα in liver although many of the results likely apply to other organs and tissues as well.

Apolipoprotein A-IV interacts synergistically with melanocortins to reduce food intake.

Science.gov (United States)

Gotoh, Koro; Liu, Min; Benoit, Stephen C; Clegg, Deborah J; Davidson, W Sean; D'Alessio, David; Seeley, Randy J; Tso, Patrick; Woods, Stephen C

2006-01-01

Apolipoprotein (apo) A-IV is an anorexigenic gastrointestinal peptide that is also synthesized in the hypothalamus. The goal of these experiments was to determine whether apo A-IV interacts with the central melanocortin (MC) system in the control of feeding. The third ventricular (i3vt) administration of a subthreshold dose of apo A-IV (0.5 microg) potentiated i3vt MC-induced (metallothionein-II, 0.03 nmol) suppression of 30-min feeding in Long-Evans rats. A subthreshold dose of the MC antagonist (SHU9119, 0.1 nmol, i3vt) completely attenuated the anorectic effect of i3vt apo A-IV (1.5 microg). The i3vt apo A-IV significantly elevated the expression of c-Fos in neurons of the paraventricular nucleus of the hypothalamus, but not in the arcuate nucleus or median eminence. In addition, c-Fos expression was not colocalized with proopiomelanocortin-positive neurons. These data support a synergistic interaction between apo A-IV and melanocortins that reduces food intake by acting downstream of the arcuate.

Molecular pathways: the role of NR4A orphan nuclear receptors in cancer.

LENUS (Irish Health Repository)

Mohan, Helen M

2012-06-15

Nuclear receptors are of integral importance in carcinogenesis. Manipulation of classic ligand-activated nuclear receptors, such as estrogen receptor blockade in breast cancer, is an important established cancer therapy. Orphan nuclear receptors, such as nuclear family 4 subgroup A (NR4A) receptors, have no known natural ligand(s). These elusive receptors are increasingly recognized as molecular switches in cell survival and a molecular link between inflammation and cancer. NR4A receptors act as transcription factors, altering expression of downstream genes in apoptosis (Fas-ligand, TRAIL), proliferation, DNA repair, metabolism, cell migration, inflammation (interleukin-8), and angiogenesis (VEGF). NR4A receptors are modulated by multiple cell-signaling pathways, including protein kinase A\\/CREB, NF-κB, phosphoinositide 3-kinase\\/AKT, c-jun-NH(2)-kinase, Wnt, and mitogen-activated protein kinase pathways. NR4A receptor effects are context and tissue specific, influenced by their levels of expression, posttranslational modification, and interaction with other transcription factors (RXR, PPAR-Υ). The subcellular location of NR4A "nuclear receptors" is also important functionally; novel roles have been described in the cytoplasm where NR4A proteins act both indirectly and directly on the mitochondria to promote apoptosis via Bcl-2. NR4A receptors are implicated in a wide variety of malignancies, including breast, lung, colon, bladder, and prostate cancer; glioblastoma multiforme; sarcoma; and acute and\\/or chronic myeloid leukemia. NR4A receptors modulate response to conventional chemotherapy and represent an exciting frontier for chemotherapeutic intervention, as novel agents targeting NR4A receptors have now been developed. This review provides a concise clinical overview of current knowledge of NR4A signaling in cancer and the potential for therapeutic manipulation.

Bone marrow mesenchymal stem cells with Nogo-66 receptor gene silencing for repair of spinal cord injury

Science.gov (United States)

Li, Zhiyuan; Zhang, Zhanxiu; Zhao, Lili; Li, Hui; Wang, Suxia; Shen, Yong

2014-01-01

We hypothesized that RNA interference to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells before transplantation might further improve neurological function in rats with spinal cord transection injury. After 2 weeks, the number of neurons and BrdU-positive cells in the Nogo-66 receptor gene silencing group was higher than in the bone marrow mesenchymal stem cell group, and significantly greater compared with the model group. After 4 weeks, behavioral performance was significantly enhanced in the model group. After 8 weeks, the number of horseradish peroxidase-labeled nerve fibers was higher in the Nogo-66 receptor gene silencing group than in the bone marrow mesenchymal stem cell group, and significantly higher than in the model group. The newly formed nerve fibers and myelinated nerve fibers were detectable in the central transverse plane section in the bone marrow mesenchymal stem cell group and in the Nogo-66 receptor gene silencing group. PMID:25206893

Do Neuroendocrine Peptides and Their Receptors Qualify as Novel Therapeutic Targets in Osteoarthritis?

Directory of Open Access Journals (Sweden)

Susanne Grässel

2018-01-01

Full Text Available Joint tissues like synovium, articular cartilage, meniscus and subchondral bone, are targets for neuropeptides. Resident cells of these tissues express receptors for various neuroendocrine-derived peptides including proopiomelanocortin (POMC-derived peptides, i.e., α-melanocyte-stimulating hormone (α-MSH, adrenocorticotropin (ACTH and β-endorphin (β-ED, and sympathetic neuropeptides like vasoactive intestinal peptide (VIP and neuropeptide y (NPY. Melanocortins attained particular attention due to their immunomodulatory and anti-inflammatory effects in several tissues and organs. In particular, α-MSH, ACTH and specific melanocortin-receptor (MCR agonists appear to have promising anti-inflammatory actions demonstrated in animal models of experimentally induced arthritis and osteoarthritis (OA. Sympathetic neuropeptides have obtained increasing attention as they have crucial trophic effects that are critical for joint tissue and bone homeostasis. VIP and NPY are implicated in direct and indirect activation of several anabolic signaling pathways in bone and synovial cells. Additionally, pituitary adenylate cyclase-activating polypeptide (PACAP proved to be chondroprotective and, thus, might be a novel target in OA. Taken together, it appears more and more likely that the anabolic effects of these neuroendocrine peptides or their respective receptor agonists/antagonists may be exploited for the treatment of patients with inflammatory and degenerative joint diseases in the future.

Avr4 promotes Cf-4 receptor-like protein association with the BAK1/SERK3 receptor-like kinase to initiate receptor endocytosis and plant immunity.

Science.gov (United States)

Postma, Jelle; Liebrand, Thomas W H; Bi, Guozhi; Evrard, Alexandre; Bye, Ruby R; Mbengue, Malick; Kuhn, Hannah; Joosten, Matthieu H A J; Robatzek, Silke

2016-04-01

The first layer of plant immunity is activated by cell surface receptor-like kinases (RLKs) and proteins (RLPs) that detect infectious pathogens. Constitutive interaction with the SUPPRESSOR OF BIR1 (SOBIR1) RLK contributes to RLP stability and kinase activity. As RLK activation requires transphosphorylation with a second associated RLK, it remains elusive how RLPs initiate downstream signaling. We employed live-cell imaging, gene silencing and coimmunoprecipitation to investigate the requirement of associated kinases for functioning and ligand-induced subcellular trafficking of Cf RLPs that mediate immunity of tomato against Cladosporium fulvum. Our research shows that after elicitation with matching effector ligands Avr4 and Avr9, BRI1-ASSOCIATED KINASE 1/SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (BAK1/SERK3) associates with Cf-4 and Cf-9. BAK1/SERK3 is required for the effector-triggered hypersensitive response and resistance of tomato against C. fulvum. Furthermore, Cf-4 interacts with SOBIR1 at the plasma membrane and is recruited to late endosomes upon Avr4 trigger, also depending on BAK1/SERK3. These observations indicate that RLP-mediated resistance and endocytosis require ligand-induced recruitment of BAK1/SERK3, reminiscent of BAK1/SERK3 interaction and subcellular fate of the FLAGELLIN SENSING 2 (FLS2) RLK. This reveals that diverse classes of cell surface immune receptors share common requirements for initiation of resistance and endocytosis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Association of MC4R gene variants with carcass and meat quality ...

African Journals Online (AJOL)

STORAGESEVER

2009-08-04

Aug 4, 2009 ... 1College of Animal Science and Technology, Northwest A and F ... MC4R belongs to a seven-transmembrane G-protein-coupled receptor which may regulate body ... targeted disruption of the MC4R gene in mice causes.

Retinoid X receptor and peroxisome proliferator-activated receptor activate an estrogen responsive gene independent of the estrogen receptor.

Science.gov (United States)

Nuñez, S B; Medin, J A; Braissant, O; Kemp, L; Wahli, W; Ozato, K; Segars, J H

1997-03-14

Estrogen receptors regulate transcription of genes essential for sexual development and reproductive function. Since the retinoid X receptor (RXR) is able to modulate estrogen responsive genes and both 9-cis RA and fatty acids influenced development of estrogen responsive tumors, we hypothesized that estrogen responsive genes might be modulated by RXR and the fatty acid receptor (peroxisome proliferator-activated receptor, PPAR). To test this hypothesis, transfection assays in CV-1 cells were performed with an estrogen response element (ERE) coupled to a luciferase reporter construct. Addition of expression vectors for RXR and PPAR resulted in an 11-fold increase in luciferase activity in the presence of 9-cis RA. Furthermore, mobility shift assays demonstrated binding of RXR and PPAR to the vitellogenin A2-ERE and an ERE in the oxytocin promoter. Methylation interference assays demonstrated that specific guanine residues required for RXR/PPAR binding to the ERE were similar to residues required for ER binding. Moreover, RXR domain-deleted constructs in transfection assays showed that activation required RXR since an RXR delta AF-2 mutant completely abrogated reporter activity. Oligoprecipitation binding studies with biotinylated ERE and (35)S-labeled in vitro translated RXR constructs confirmed binding of delta AF-2 RXR mutant to the ERE in the presence of baculovirus-expressed PPAR. Finally, in situ hybridization confirmed RXR and PPAR mRNA expression in estrogen responsive tissues. Collectively, these data suggest that RXR and PPAR are present in reproductive tissues, are capable of activating estrogen responsive genes and suggest that the mechanism of activation may involve direct binding of the receptors to estrogen response elements.

Allelic association of the D2 dopamine receptor gene with receptor-binding characteristics in alcoholism

International Nuclear Information System (INIS)

Noble, E.P.; Blum, K.; Ritchie, T.; Montgomery, A.; Sheridan, P.J.

1991-01-01

The allelic association of the human D2 dopamine receptor gene with the binding characteristics of the D2 dopamine receptor was determined in 66 brains of alcoholic and non-alcoholic subjects. In a blinded experiment, DNA from the cerebral cortex was treated with the restriction endonuclease Taql and probed with a 1.5-kilobase (kb) digest of a clone (lambda hD2G1) of the human D2 dopamine receptor gene. The binding characteristics (Kd [binding affinity] and Bmax [number of binding sites]) of the D2 dopamine receptor were determined in the caudate nuclei of these brains using tritiated spiperone as the ligand. The adjusted Kd was significantly lower in alcoholic than in nonalcoholic subjects. In subjects with the A1 allele, in whom a high association with alcoholism was found, the Bmax was significantly reduced compared with the Bmax of subjects with the A2 allele. Moreover, a progressively reduced Bmax was found in subjects with A2/A2, A1/A2, and A1/A1 alleles, with subjects with A2/A2 having the highest mean values, and subjects with A1/A1, the lowest. The polymorphic pattern of the D2 dopamine receptor gene and its differential expression of receptors suggests the involvement of the dopaminergic system in conferring susceptibility to at least one subtype of severe alcoholism

The Role of Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4) Gene, Thyroid Stimulating Hormone Receptor (TSHR) Gene and Regulatory T-cells as Risk Factors for Relapse in Patients with Graves Disease.

Science.gov (United States)

Eliana, Fatimah; Suwondo, Pradana; Asmarinah, Asmarinah; Harahap, Alida; Djauzi, Samsuridjal; Prihartono, Joedo; Pemayun, Tjokorda Gde Dalem

2017-07-01

graves' disease (GD) is the most common condition of thyrotoxicosis. The management of GD is initiated with the administration of antithyroid drugs; however, it requires a long time to achieve remission. In reality more than 50% of patients who had remission may be at risk for relapse after the drug is stopped. This study aimed to evaluate the role of clinical factors such as smoking habit, degree of ophtalmopathy, degree of thyroid enlargement; genetic factors such as CTLA-4 gene on nucleotide 49 at codon 17 of exon 1, CTLA-4 gene of promotor -318, TSHR gene polymorphism rs2268458 of intron 1; and immunological factors such as regulatory T cells (Treg) and thyroid receptor antibody (TRAb); that affecting the relapse of patients with Graves' disease in Indonesia. this was a case-control study, that compared 72 subjects who had relapse and 72 subjects without relapse at 12 months after cessation of antithyroid treatment, who met the inclusion criteria. Genetic polymorphism examination was performed using PCR-RFLP. The number of regulatory T cells was counted using flow cytometry analysis and ELISA was used to measure TRAb. The logistic regression was used since the dependent variables were categorical variables. the analysis of this study demonstrated that there was a correlation between relapse of disease and family factors (p=0.008), age at diagnosis (p=0.021), 2nd degree of Graves' ophthalmopathy (p=0.001), enlarged thyroid gland, which exceeded the lateral edge of the sternocleidomastoid muscles (p=0.040), duration of remission period (p=0.029), GG genotype of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1 (p=0.016), CC genotype of TSHR gene on the rs2268458 of intron 1 (p=0.003), the number of regulatory T cells (p=0.001) and TRAb levels (p=0.002). genetic polymorphisms of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1, TSHR gene SNP rs2268458 of intron 1, number of regulatory T cells and TRAb levels play a role as risk factors for relapse in

The Role of Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4 Gene, Thyroid Stimulating Hormone Receptor (TSHR Gene and Regulatory T-cells as Risk Factors for Relapse in Patients with Graves Disease

Directory of Open Access Journals (Sweden)

Fatimah Eliana

2017-11-01

Full Text Available Background: graves’ disease (GD is the most common condition of thyrotoxicosis. The management of GD is initiated with the administration of antithyroid drugs; however, it requires a long time to achieve remission. In reality more than 50% of patients who had remission may be at risk for relapse after the drug is stopped. This study aimed to evaluate the role of clinical factors such as smoking habit, degree of ophtalmopathy, degree of thyroid enlargement; genetic factors such as CTLA-4 gene on nucleotide 49 at codon 17 of exon 1, CTLA-4 gene of promotor -318, TSHR gene polymorphism rs2268458 of intron 1; and immunological factors such as regulatory T cells (Treg and thyroid receptor antibody (TRAb; that affecting the relapse of patients with Graves’ disease in Indonesia. Methods: this was a case-control study, that compared 72 subjects who had relapse and 72 subjects without relapse at 12 months after cessation of antithyroid treatment, who met the inclusion criteria. Genetic polymorphism examination was performed using PCR-RFLP. The number of regulatory T cells was counted using flow cytometry analysis and ELISA was used to measure TRAb. The logistic regression was used since the dependent variables were categorical variables. Results: the analysis of this study demonstrated that there was a correlation between relapse of disease and family factors (p=0.008, age at diagnosis (p=0.021, 2nd degree of Graves’ ophthalmopathy (p=0.001, enlarged thyroid gland, which exceeded the lateral edge of the sternocleidomastoid muscles (p=0.040, duration of remission period (p=0.029, GG genotype of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1 (p=0.016, CC genotype of TSHR gene on the rs2268458 of intron 1 (p=0.003, the number of regulatory T cells (p=0.001 and TRAb levels (p=0.002. Conclusion: genetic polymorphisms of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1, TSHR gene SNP rs2268458 of intron 1, number of regulatory T cells and

No substantial changes in estrogen receptor and estrogen-related receptor orthologue gene transcription in Marisa cornuarietis exposed to estrogenic chemicals☆☆☆

Science.gov (United States)

Bannister, Richard; Beresford, Nicola; Granger, David W.; Pounds, Nadine A.; Rand-Weaver, Mariann; White, Roger; Jobling, Susan; Routledge, Edwin J.

2013-01-01

Estrogen receptor orthologues in molluscs may be targets for endocrine disruptors, although mechanistic evidence is lacking. Molluscs are reported to be highly susceptible to effects caused by very low concentrations of environmental estrogens which, if substantiated, would have a major impact on the risk assessment of many chemicals. The present paper describes the most thorough evaluation to-date of the susceptibility of Marisa cornuarietis ER and ERR gene transcription to modulation by vertebrate estrogens in vivo and in vitro. We investigated the effects of estradiol-17β and 4-tert-Octylphenol exposure on in vivo estrogen receptor (ER) and estrogen-related receptor (ERR) gene transcription in the reproductive and neural tissues of the gastropod snail M. cornuarietis over a 12-week period. There was no significant effect (p > 0.05) of treatment on gene transcription levels between exposed and non-exposed snails. Absence of a direct interaction of estradiol-17β and 4-tert-Octylphenol with mollusc ER and ERR protein was also supported by in vitro studies in transfected HEK-293 cells. Additional in vitro studies with a selection of other potential ligands (including methyl-testosterone, 17α-ethinylestradiol, 4-hydroxytamoxifen, diethylstilbestrol, cyproterone acetate and ICI182780) showed no interaction when tested using this assay. In repeated in vitro tests, however, genistein (with mcER-like) and bisphenol-A (with mcERR) increased reporter gene expression at high concentrations only (>10−6 M for Gen and >10−5 M for BPA, respectively). Like vertebrate estrogen receptors, the mollusc ER protein bound to the consensus vertebrate estrogen-response element (ERE). Together, these data provide no substantial evidence that mcER-like and mcERR activation and transcript levels in tissues are modulated by the vertebrate estrogen estradiol-17β or 4-tert-Octylphenol in vivo, or that other ligands of vertebrate ERs and ERRs (with the possible exception of

Dopamine receptor gene expression by enkephalin neurons in rat forebrain

International Nuclear Information System (INIS)

Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B.

1990-01-01

In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons

Dopamine receptor gene expression by enkephalin neurons in rat forebrain

Energy Technology Data Exchange (ETDEWEB)

Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B. (Universite de Bordeaux II (France))

1990-01-01

In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons.

Receptor-Targeted Nipah Virus Glycoproteins Improve Cell-Type Selective Gene Delivery and Reveal a Preference for Membrane-Proximal Cell Attachment.

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Ruben R Bender

2016-06-01

Full Text Available Receptor-targeted lentiviral vectors (LVs can be an effective tool for selective transfer of genes into distinct cell types of choice. Moreover, they can be used to determine the molecular properties that cell surface proteins must fulfill to act as receptors for viral glycoproteins. Here we show that LVs pseudotyped with receptor-targeted Nipah virus (NiV glycoproteins effectively enter into cells when they use cell surface proteins as receptors that bring them closely enough to the cell membrane (less than 100 Å distance. Then, they were flexible in receptor usage as demonstrated by successful targeting of EpCAM, CD20, and CD8, and as selective as LVs pseudotyped with receptor-targeted measles virus (MV glycoproteins, the current standard for cell-type specific gene delivery. Remarkably, NiV-LVs could be produced at up to two orders of magnitude higher titers compared to their MV-based counterparts and were at least 10,000-fold less effectively neutralized than MV glycoprotein pseudotyped LVs by pooled human intravenous immunoglobulin. An important finding for NiV-LVs targeted to Her2/neu was an about 100-fold higher gene transfer activity when particles were targeted to membrane-proximal regions as compared to particles binding to a more membrane-distal epitope. Likewise, the low gene transfer activity mediated by NiV-LV particles bound to the membrane distal domains of CD117 or the glutamate receptor subunit 4 (GluA4 was substantially enhanced by reducing receptor size to below 100 Å. Overall, the data suggest that the NiV glycoproteins are optimally suited for cell-type specific gene delivery with LVs and, in addition, for the first time define which parts of a cell surface protein should be targeted to achieve optimal gene transfer rates with receptor-targeted LVs.

Cell-specific targeting by heterobivalent ligands.

Science.gov (United States)

Josan, Jatinder S; Handl, Heather L; Sankaranarayanan, Rajesh; Xu, Liping; Lynch, Ronald M; Vagner, Josef; Mash, Eugene A; Hruby, Victor J; Gillies, Robert J

2011-07-20

Current cancer therapies exploit either differential metabolism or targeting to specific individual gene products that are overexpressed in aberrant cells. The work described herein proposes an alternative approach--to specifically target combinations of cell-surface receptors using heteromultivalent ligands ("receptor combination approach"). As a proof-of-concept that functionally unrelated receptors can be noncovalently cross-linked with high avidity and specificity, a series of heterobivalent ligands (htBVLs) were constructed from analogues of the melanocortin peptide ligand ([Nle(4), dPhe(7)]-α-MSH) and the cholecystokinin peptide ligand (CCK-8). Binding of these ligands to cells expressing the human Melanocortin-4 receptor and the Cholecystokinin-2 receptor was analyzed. The MSH(7) and CCK(6) were tethered with linkers of varying rigidity and length, constructed from natural and/or synthetic building blocks. Modeling data suggest that a linker length of 20-50 Å is needed to simultaneously bind these two different G-protein coupled receptors (GPCRs). These ligands exhibited up to 24-fold enhancement in binding affinity to cells that expressed both (bivalent binding), compared to cells with only one (monovalent binding) of the cognate receptors. The htBVLs had up to 50-fold higher affinity than that of a monomeric CCK ligand, i.e., Ac-CCK(6)-NH(2). Cell-surface targeting of these two cell types with labeled heteromultivalent ligand demonstrated high avidity and specificity, thereby validating the receptor combination approach. This ability to noncovalently cross-link heterologous receptors and target individual cells using a receptor combination approach opens up new possibilities for specific cell targeting in vivo for therapy or imaging.

Dopamine receptors genes polymorphisms in Parkinson patients with levodopa-induced dyskinesia

NARCIS (Netherlands)

Pozhidaev, Ivan V; Alifirova, V. M.; Freidin, Maxim B.; Zhukova, I.A.; Fedorenko, Olga Yu; Osmanova, Diana Z; Mironova, Y.S.; Wilffert, Berend; Ivanova, Svetlana A.; Loonen, Antonius

2017-01-01

Dopamine receptors genes polymorphisms in Parkinson patients with levodopa-induced dyskinesia I. Pozhidaev(1), V.M. Alifirova(2), M.B. Freidin(3), I.A. Zhukova(2), O.Y. Fedorenko(1), D.Z. Osmanova(1), Y.S. Mironova(2), B. Wilffert(4), S.A. Ivanova(1), A.J.M. Loonen(5) (1)Mental Health Research

Functional characterization of bursicon receptor and genome-wide analysis for identification of genes affected by bursicon receptor RNAi

Science.gov (United States)

Bai, Hua; Palli, Subba R.

2010-01-01

Bursicon is an insect neuropeptide hormone that is secreted from the central nervous system into the hemolymph and initiates cuticle tanning. The receptor for bursicon is encoded by the rickets (rk) gene and belongs to the G protein-coupled receptor (GPCR) superfamily. The bursicon and its receptor regulate cuticle tanning as well as wing expansion after adult eclosion. However, the molecular action of bursicon signaling remains unclear. We utilized RNA interference (RNAi) and microarray to study the function of the bursicon receptor (Tcrk) in the model insect, Tribolium castaneum. The data included here showed that in addition to cuticle tanning and wing expansion reported previously, Tcrk is also required for development and expansion of integumentary structures and adult eclosion. Using custom microarrays, we identified 24 genes that are differentially expressed between Tcrk RNAi and control insects. Knockdown in the expression of one of these genes, TC004091, resulted in the arrest of adult eclosion. Identification of genes that are involved in bursicon receptor mediated biological processes will provide tools for future studies on mechanisms of bursicon action. PMID:20457145

Vitamin D receptor and estrogen receptor gene polymorphisms in postmenopausal Danish women

DEFF Research Database (Denmark)

Bagger, Y Z; Hassager, C; Heegaard, Anne-Marie

2000-01-01

To investigate the polymorphisms of the vitamin D receptor (VDR) and estrogen receptor (ER) genes in relation to biochemical markers of bone turnover (serum osteocalcin and urinary collagen type I degradation products (CrossLaps), and to study ER genotypes in relation to serum lipoproteins, blood...... pressure, or changes in these parameters after 2 years of hormone replacement therapy (HRT) in 499 Danish postmenopausal women....

Are Toll-like receptor gene polymorphisms associated with prostate cancer?

International Nuclear Information System (INIS)

Kutikhin, Anton G; Yuzhalin, Arseniy E

2012-01-01

The suggestion that there is a connection between chronic intraprostatic inflammation and prostate cancer was declared some years ago. As Toll-like receptors (TLRs) are the key players in the processes of chronic intraprostatic inflammation, there is a hypothesis that TLR gene polymorphisms may be associated with prostate cancer risk. Although a number of comprehensive studies have been conducted on large samples in various countries, reliable connections between these single nucleotide polymorphisms and prostate cancer risk, stage, grade, aggressiveness, ability to metastasize, and mortality have not been detected. Results have also varied slightly in different populations. The data obtained regarding the absence of connection between the polymorphisms of the genes encoding interleukin-1 receptor-associated kinases (IRAK1 and IRAK4) and prostate cancer risk might indicate a lack of association between inherited variation in the TLR signaling pathway and prostate cancer risk. It is possible to consider that polymorphisms of genes encoding TLRs and proteins of the TLR pathway also do not play a major role in the etiology and pathogenesis of prostate cancer. Feasibly, it would be better to focus research on associations between TLR single nucleotide polymorphisms and cancer risk in other infection-related cancer types

Association of arginine vasopressin receptor 1a gene polymorphisms with hepatorenal syndrome

International Nuclear Information System (INIS)

Wang, C.; Luo, X.; Ye, J.; Liu, S.; Miu, L.; Bao, J.; Wang, F.; Yu, Z.

2017-01-01

To assess the association of arginine vasopressin receptor 1a gene single nucleotide polymorphisms with type I hepatorenal syndrome. Methods: The case-control study was conducted at the Hangzhou City Xixi Hospital, Hangzhou, China, from January 2012 to June 2014, and comprised patients with type I hepatorenal syndrome and individuals with cirrhosis who acted as the control group. Arginine vasopressin receptor 1a gene rs113481894 locus single nucleotide polymorphisms were analysed by high-resolution melting methods. Statistical analysis was performed using SPSS 17. Results: Of the 60 participants, 28(46.7%) were in the hepatorenal syndrome group and 32(53.3%) were controls. The mean age was 42.21+-11.30years in the hepatorenal syndrome group and 43.69+-12.60 in the control group (p=0.64). Mean total bilirubin, albumin and prothrombin activity levels were 154.76+-51.58, 49.30+-24.67 and 33.42+-3.69 in the hepatorenal syndrome group compared to 181.26+-64.46, 41.78+-17.52 and 32.98+-4.81 among controls (p=0.09, p=0.18 and p=0.70). Statistically significant differences were found in the distributions of arginine vasopressin receptor 1a gene rs113481894 locus T allele between type I hepatorenal syndrome patients and the control group (odds ratio= 2.230; p= 0.040). Conclusion: T allele located at arginine vasopressin receptor 1a receptor promoter rs113481894 locus may be associated with the pathogenesis of type I hepatorenal syndrome. (author)

Modeling structure of G protein-coupled receptors in huan genome

KAUST Repository

Zhang, Yang

2016-01-26

G protein-coupled receptors (or GPCRs) are integral transmembrane proteins responsible to various cellular signal transductions. Human GPCR proteins are encoded by 5% of human genes but account for the targets of 40% of the FDA approved drugs. Due to difficulties in crystallization, experimental structure determination remains extremely difficult for human GPCRs, which have been a major barrier in modern structure-based drug discovery. We proposed a new hybrid protocol, GPCR-I-TASSER, to construct GPCR structure models by integrating experimental mutagenesis data with ab initio transmembrane-helix assembly simulations, assisted by the predicted transmembrane-helix interaction networks. The method was tested in recent community-wide GPCRDock experiments and constructed models with a root mean square deviation 1.26 Å for Dopamine-3 and 2.08 Å for Chemokine-4 receptors in the transmembrane domain regions, which were significantly closer to the native than the best templates available in the PDB. GPCR-I-TASSER has been applied to model all 1,026 putative GPCRs in the human genome, where 923 are found to have correct folds based on the confidence score analysis and mutagenesis data comparison. The successfully modeled GPCRs contain many pharmaceutically important families that do not have previously solved structures, including Trace amine, Prostanoids, Releasing hormones, Melanocortins, Vasopressin and Neuropeptide Y receptors. All the human GPCR models have been made publicly available through the GPCR-HGmod database at http://zhanglab.ccmb.med.umich.edu/GPCR-HGmod/ The results demonstrate new progress on genome-wide structure modeling of transmembrane proteins which should bring useful impact on the effort of GPCR-targeted drug discovery.

Non-coplanar polychlorinated biphenyls (PCBs) are direct agonists for the human pregnane-X receptor and constitutive androstane receptor, and activate target gene expression in a tissue-specific manner

International Nuclear Information System (INIS)

Al-Salman, Fadheela; Plant, Nick

2012-01-01

The polychlorinated biphenyl group possesses high environmental persistence, leading to bioaccumulation and a number of adverse effects in mammals. Whilst coplanar PCBs elicit their toxic effects through agonism of the aryl hydrocarbon receptor; however, non-coplanar PCBs are not ligands for AhR, but may be ligands for members of the nuclear receptor family of proteins. To better understand the biological actions of non-coplanar PCBs, we have undertaken a systematic analysis of their ability to activate PXR and CAR-mediated effects. Cells were exposed to a range of non-coplanar PCBs (99, 138, 153, 180 and 194), or the coplanar PCB77: Direct activation of PXR and CAR was measured using a mammalian receptor activation assay in human liver cells, with rifampicin and CITCO used as positive controls ligands for PXR and CAR, respectively; activation of target gene expression was examined using reporter gene plasmids for CYP3A4 and MDR1 transfected into liver, intestine and lung cell lines. Several of the non-coplanar PCBs directly activated PXR and CAR, whilst the coplanar PCB77 did not. Non-coplanar PCBs were also able to activate PXR/CAR target gene expression in a substitution- and tissue-specific manner. Non-coplanar PCBs act as direct activators for the nuclear receptors PXR and CAR, and are able to elicit transcriptional activation of target genes in a substitution- and tissue-dependent manner. Chronic activation of PXR/CAR is linked to adverse effects and must be included in any risk assessment of PCBs. -- Highlights: ► Several Non-coplanar PCBs are able to directly activate both PXR and CAR in vitro. ► PCB153 is the most potent direct activator of PXR and CAR nuclear receptors. ► Non-coplanar PCB activation of CYP3A4/MDR1 reporter genes is structure-dependent. ► Non-coplanar PCB activate CYP3A4/MDR1 reporter genes in a tissue-dependent. ► PCB153 is the most potent activator of PXR/CAR target gene in all tissues.

Genome-wide identification of nuclear receptor (NR) superfamily genes in the copepod Tigriopus japonicus.

Science.gov (United States)

Hwang, Dae-Sik; Lee, Bo-Young; Kim, Hui-Su; Lee, Min Chul; Kyung, Do-Hyun; Om, Ae-Son; Rhee, Jae-Sung; Lee, Jae-Seong

2014-11-18

Nuclear receptors (NRs) are a large superfamily of proteins defined by a DNA-binding domain (DBD) and a ligand-binding domain (LBD). They function as transcriptional regulators to control expression of genes involved in development, homeostasis, and metabolism. The number of NRs differs from species to species, because of gene duplications and/or lineage-specific gene losses during metazoan evolution. Many NRs in arthropods interact with the ecdysteroid hormone and are involved in ecdysone-mediated signaling in arthropods. The nuclear receptor superfamily complement has been reported in several arthropods, including crustaceans, but not in copepods. We identified the entire NR repertoire of the copepod Tigriopus japonicus, which is an important marine model species for ecotoxicology and environmental genomics. Using whole genome and transcriptome sequences, we identified a total of 31 nuclear receptors in the genome of T. japonicus. Nomenclature of the nuclear receptors was determined based on the sequence similarities of the DNA-binding domain (DBD) and ligand-binding domain (LBD). The 7 subfamilies of NRs separate into five major clades (subfamilies NR1, NR2, NR3, NR4, and NR5/6). Although the repertoire of NR members in, T. japonicus was similar to that reported for other arthropods, there was an expansion of the NR1 subfamily in Tigriopus japonicus. The twelve unique nuclear receptors identified in T. japonicus are members of NR1L. This expansion may be a unique lineage-specific feature of crustaceans. Interestingly, E78 and HR83, which are present in other arthropods, were absent from the genomes of T. japonicus and two congeneric copepod species (T. japonicus and Tigriopus californicus), suggesting copepod lineage-specific gene loss. We identified all NR receptors present in the copepod, T. japonicus. Knowledge of the copepod nuclear receptor repertoire will contribute to a better understanding of copepod- and crustacean-specific NR evolution.

Association of Common Polymorphisms in the Nicotinic Acetylcholine Receptor Alpha4 Subunit Gene with an Electrophysiological Endophenotype in a Large Population-Based Sample.

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A Mobascher

Full Text Available Variation in genes coding for nicotinic acetylcholine receptor (nAChR subunits affect cognitive processes and may contribute to the genetic architecture of neuropsychiatric disorders. Single nucleotide polymorphisms (SNPs in the CHRNA4 gene that codes for the alpha4 subunit of alpha4/beta2-containing receptors have previously been implicated in aspects of (mostly visual attention and smoking-related behavioral measures. Here we investigated the effects of six synonymous but functional CHRNA4 exon 5 SNPs on the N100 event-related potential (ERP, an electrophysiological endophenotype elicited by a standard auditory oddball. A total of N = 1,705 subjects randomly selected from the general population were studied with electroencephalography (EEG as part of the German Multicenter Study on nicotine addiction. Two of the six variants, rs1044396 and neighboring rs1044397, were significantly associated with N100 amplitude. This effect was pronounced in females where we also observed an effect on reaction time. Sequencing of the complete exon 5 region in the population sample excluded the existence of additional/functional variants that may be responsible for the observed effects. This is the first large-scale population-based study investigation the effects of CHRNA4 SNPs on brain activity measures related to stimulus processing and attention. Our results provide further evidence that common synonymous CHRNA4 exon 5 SNPs affect cognitive processes and suggest that they also play a role in the auditory system. As N100 amplitude reduction is considered a schizophrenia-related endophenotype the SNPs studied here may also be associated with schizophrenia outcome measures.

IGF-I, IGF-II, and Insulin Stimulate Different Gene Expression Responses through Binding to the IGF-I Receptor

DEFF Research Database (Denmark)

Versteyhe, Soetkin; Klaproth, Birgit; Borup, Rehannah

2013-01-01

Insulin and the insulin-like growth factors (IGF)-I and -II are closely related peptides important for regulation of metabolism, growth, differentiation, and development. The IGFs exert their main effects through the IGF-I receptor. Although the insulin receptor is the main physiological receptor...... for insulin, this peptide hormone can also bind at higher concentrations to the IGF-I receptor and exert effects through it. We used microarray gene expression profiling to investigate the gene expression regulated by IGF-I, IGF-II, and insulin after stimulation of the IGF-I receptor. Fibroblasts from mice......, knockout for IGF-II and the IGF-II/cation-independent mannose-6-phosphate receptor, and expressing functional IGF-I but no insulin receptors, were stimulated for 4 h with equipotent saturating concentrations of insulin, IGF-I, and IGF-II. Each ligand specifically regulated a group of transcripts...

Elevation of D4 dopamine receptor mRNA in postmortem schizophrenic brain.

Science.gov (United States)

Stefanis, N C; Bresnick, J N; Kerwin, R W; Schofield, W N; McAllister, G

1998-01-01

The D4 dopamine (DA) receptor has been proposed to be a target for the development of a novel antipsychotic drug based on its pharmacological and distribution profile. There is much interest in whether D4 DA receptor levels are altered in schizophrenia, but the lack of an available receptor subtype-specific radioligand made this difficult to quantitate. In this study, we examined whether D4 mRNA levels are altered in different brain regions of schizophrenics compared to controls. Ribonuclease protection assays were carried out on total RNA samples isolated postmortem from frontal cortex and caudate brain regions of schizophrenics and matched controls. 32P-labelled RNA probes to the D4 DA receptor and to the housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase (G3PDH), were hybridised with the RNA samples, digested with ribonucleases to remove unhybridised probe, and separated on 6% sequencing gels. Densitometer analysis on the subsequent autoradiogams was used to calculate the relative optical density of D4 mRNA compared to G3PDH mRNA. Statistical analysis of the data revealed a 3-fold higher level (P<0.011) of D4 mRNA in the frontal cortex of schizophrenics compared to controls. No increase was seen in caudate. D4 receptors could play a role in mediating dopaminergic activity in frontal cortex, an activity which may be malfunctioning in schizophrenia.

Vitamin D receptor FokI genotype may modify the susceptibility to schizophrenia and bipolar mood disorder by regulation of dopamine D1 receptor gene expression.

Science.gov (United States)

Ahmadi, S; Mirzaei, K; Hossein-Nezhad, A; Shariati, G

2012-10-01

This study is designed to test association of FOKI polymorphism in Vitamin D receptor (VDR) gene and its potential effect on expression of dopamine D1 receptor in schizophrenia and bipolar mood disorder as well as in healthy individuals. In this case-control study 196 patient with schizophrenia, 119 patients with bipolar mood disorder and 192 healthy individuals as the control group were recruited. All psychiatric disorders were diagnosed according to DSM IV criteria. Healthy control group denied any family history of such disorders. FOKI was genotyped by means of PCR-RFLP method. The mRNA was extracted from the peripheral blood mononuclear cells (PBMC) and the cDNA was synthesized. Frequency of ff genotype was more common in patients with bipolar disorders compared to the healthy control group (Odds ratio=1.84, 95% CI; 0.81 to 4.17) with increased relative risk (Relative risk=1.31, CI 95%; 0.86 to 1.99). There were significant differences between relative expressions of dopamine D1 receptor gene in various genotypes. Our results indicated that the ff genotype was associated with lower expression of dopamine D1 receptor gene. VDR as a nuclear receptor may contribute to bipolar disorders via modification of the expression of the neurotransmitters receptor such as dopamine.

High-throughput Microarray Detection of Vomeronasal Receptor Gene Expression in Rodents

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Xiaohong Zhang

2010-11-01

Full Text Available We performed comprehensive data mining to explore the vomeronasal receptor (V1R & V2R repertoires in mouse and rat using the mm5 and rn3 genome, respectively. This bioinformatic analysis was followed by investigation of gene expression using a custom designed high-density oligonucleotide array containing all of these receptors and other selected genes of interest. This array enabled us to detect the specific expression of V1R and V2Rs which were previously identified solely based on computational prediction from gene sequence data, thereby establishing that these genes are indeed part of the vomeronasal system, especially the V2Rs. 168 V1Rs and 98 V2Rs were detected to be highly enriched in mouse vomeronasal organ (VNO, and 108 V1Rs and 87 V2Rs in rat VNO. We monitored the expression profile of mouse VR genes in other non-VNO tissues with the result that some VR genes were re-designated as VR-like genes based on their non-olfactory expression pattern. Temporal expression profiles for mouse VR genes were characterized and their patterns were classified, revealing the developmental dynamics of these so-called pheromone receptors. We found numerous patterns of temporal expression which indicate possible behavior-related functions. The uneven composition of VR genes in certain patterns suggests a functional differentiation between the two types of VR genes. We found the coherence between VR genes and transcription factors in terms of their temporal expression patterns. In situ hybridization experiments were performed to evaluate the cell number change over time for selected receptor genes.

Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus).

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Morris, Katrina M; Mathew, Marina; Waugh, Courtney; Ujvari, Beata; Timms, Peter; Polkinghorne, Adam; Belov, Katherine

2015-10-15

Koalas (Phascolarctos cinereus), an iconic Australian marsupial, are being heavily impacted by the spread of Chlamydia pecorum, an obligate intracellular bacterial pathogen. Koalas vary in their response to this pathogen, with some showing no symptoms, while others suffer severe symptoms leading to infertility, blindness or death. Little is known about the pathology of this disease and the immune response against it in this host. Studies have demonstrated that natural killer (NK) cells, key components of the innate immune system, are involved in the immune response to chlamydial infections in humans. These cells can directly lyse cells infected by intracellular pathogens and their ability to recognise these infected cells is mediated through NK receptors on their surface. These are encoded in two regions of the genome, the leukocyte receptor complex (LRC) and the natural killer complex (NKC). These two families evolve rapidly and different repertoires of genes, which have evolved by gene duplication, are seen in different species. In this study we aimed to characterise genes belonging to the NK receptor clusters in the koala by searching available koala transcriptomes using a combination of search methods. We developed a qPCR assay to quantify relative expression of four genes, two encoded within the NK receptor cluster (CLEC1B, CLEC4E) and two known to play a role in NK response to Chalmydia in humans (NCR3, PRF1). We found that the NK receptor repertoire of the koala closely resembles that of the Tasmanian devil, with minimal genes in the NKC, but with lineage specific expansions in the LRC. Additional genes important for NK cell activity, NCR3 and PRF1, were also identified and characterised. In a preliminary study to investigate whether these genes are involved in the koala immune response to infection by its chlamydial pathogen, C. pecorum, we investigated the expression of four genes in koalas with active chlamydia infection, those with past infection and

Variation in the MC4R gene is associated with bone phenotypes in elderly Swedish women.

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Gaurav Garg

Full Text Available Osteoporosis is characterized by reduced bone mineral density (BMD and increased fracture risk. Fat mass is a determinant of bone strength and both phenotypes have a strong genetic component. In this study, we examined the association between obesity associated polymorphisms (SNPs with body composition, BMD, Ultrasound (QUS, fracture and biomarkers (Homocysteine (Hcy, folate, Vitamin D and Vitamin B12 for obesity and osteoporosis. Five common variants: rs17782313 and rs1770633 (melanocortin 4 receptor (MC4R; rs7566605 (insulin induced gene 2 (INSIG2; rs9939609 and rs1121980 (fat mass and obesity associated (FTO were genotyped in 2 cohorts of Swedish women: PEAK-25 (age 25, n = 1061 and OPRA (age 75, n = 1044. Body mass index (BMI, total body fat and lean mass were strongly positively correlated with QUS and BMD in both cohorts (r(2 = 0.2-0.6. MC4R rs17782313 was associated with QUS in the OPRA cohort and individuals with the minor C-allele had higher values compared to T-allele homozygotes (TT vs. CT vs.100 vs. 103 vs. 103; p = 0.002; (SOS: 1521 vs. 1526 vs. 1524; p = 0.008; (Stiffness index: 69 vs. 73 vs. 74; p = 0.0006 after adjustment for confounders. They also had low folate (18 vs. 17 vs. 16; p = 0.03 and vitamin D (93 vs. 91 vs. 90; p = 0.03 and high Hcy levels (13.7 vs 14.4 vs. 14.5; p = 0.06. Fracture incidence was lower among women with the C-allele, (52% vs. 58%; p = 0.067. Variation in MC4R was not associated with BMD or body composition in either OPRA or PEAK-25. SNPs close to FTO and INSIG2 were not associated with any bone phenotypes in either cohort and FTO SNPs were only associated with body composition in PEAK-25 (p≤0.001. Our results suggest that genetic variation close to MC4R is associated with quantitative ultrasound and risk of fracture.

Dopamine D4 receptor gene and religious affiliation correlate with dictator game altruism in males and not females: evidence for gender-sensitive gene × culture interaction.

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Jiang, Yushi; Bachner-Melman, Rachel; Chew, Soo Hong; Ebstein, Richard P

2015-01-01

On a large sample of 2288 Han Chinese undergraduates, we investigated how religion and DRD4 are related to human altruistic giving behavior as measured with the Andreoni-Miller Dictator Game. This game enables us to clearly specify (non-)selfishness, efficiency, and fairness motives for sharing. Participants were further classified into religious categories (Christian, Buddhist-Tao, and No Religion) based on self-reports, and genotyped for the dopamine D4 receptor (DRD4) gene exon III VNTR. Our analysis revealed a significant interaction between religion and DRD4 correlated with giving behavior solely among males: Whereas no significant association between religion and sharing decisions was observed in the majority 4R/4R genotype group, a significant difference in giving behavior between Christian and non-Christian males was seen in the non-4R/4R group, with Christian men being overall more altruistic (less selfish and fairer) than non-Christian men. These results support the vantage sensitivity hypothesis regarding DRD4 that the non-4R/4R "susceptibility" genotype is more responsive to a positive environment provided by some religions.

Evolution of the C-Type Lectin-Like Receptor Genes of the DECTIN-1 Cluster in the NK Gene Complex

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Susanne Sattler

2012-01-01

Full Text Available Pattern recognition receptors are crucial in initiating and shaping innate and adaptive immune responses and often belong to families of structurally and evolutionarily related proteins. The human C-type lectin-like receptors encoded in the DECTIN-1 cluster within the NK gene complex contain prominent receptors with pattern recognition function, such as DECTIN-1 and LOX-1. All members of this cluster share significant homology and are considered to have arisen from subsequent gene duplications. Recent developments in sequencing and the availability of comprehensive sequence data comprising many species showed that the receptors of the DECTIN-1 cluster are not only homologous to each other but also highly conserved between species. Even in Caenorhabditis elegans, genes displaying homology to the mammalian C-type lectin-like receptors have been detected. In this paper, we conduct a comprehensive phylogenetic survey and give an up-to-date overview of the currently available data on the evolutionary emergence of the DECTIN-1 cluster genes.

Investigation of Gamma-aminobutyric acid (GABA A receptors genes and migraine susceptibility

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Ciccodicola Alfredo

2008-12-01

Full Text Available Abstract Background Migraine is a neurological disorder characterized by recurrent attacks of severe headache, affecting around 12% of Caucasian populations. It is well known that migraine has a strong genetic component, although the number and type of genes involved is still unclear. Prior linkage studies have reported mapping of a migraine gene to chromosome Xq 24–28, a region containing a cluster of genes for GABA A receptors (GABRE, GABRA3, GABRQ, which are potential candidate genes for migraine. The GABA neurotransmitter has been implicated in migraine pathophysiology previously; however its exact role has not yet been established, although GABA receptors agonists have been the target of therapeutic developments. The aim of the present research is to investigate the role of the potential candidate genes reported on chromosome Xq 24–28 region in migraine susceptibility. In this study, we have focused on the subunit GABA A receptors type ε (GABRE and type θ (GABRQ genes and their involvement in migraine. Methods We have performed an association analysis in a large population of case-controls (275 unrelated Caucasian migraineurs versus 275 controls examining a set of 3 single nucleotide polymorphisms (SNPs in the coding region (exons 3, 5 and 9 of the GABRE gene and also the I478F coding variant of the GABRQ gene. Results Our study did not show any association between the examined SNPs in our test population (P > 0.05. Conclusion Although these particular GABA receptor genes did not show positive association, further studies are necessary to consider the role of other GABA receptor genes in migraine susceptibility.

Beneficial effects of (pGlu-Gln)-CCK-8 on energy intake and metabolism in high fat fed mice are associated with alterations of hypothalamic gene expression.

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Montgomery, I A; Irwin, N; Flatt, P R

2013-06-01

Cholecystokinin (CCK) is a gastrointestinal hormone with potential therapeutic promise for obesity-diabetes. The present study examined the effects of twice daily administration of the N-terminally modified stable CCK-8 analogue, (pGlu-Gln)-CCK-8, on metabolic control and hypothalamic gene expression in high fat fed mice. Sub-chronic twice daily injection of (pGlu-Gln)-CCK-8 for 16 days significantly decreased body weight (penergy intake (pcontrols. Furthermore, (pGlu-Gln)-CCK-8 markedly improved glucose tolerance (p<0.05) and insulin sensitivity (p<0.05). Assessment of hypothalamic gene expression on day 16 revealed significantly elevated NPY (p<0.05) and reduced POMC (p<0.05) and MC4R (p<0.05) mRNA expression in (pGlu-Gln)-CCK-8 treated mice. High fat feeding or (pGlu-Gln)-CCK-8 treatment had no significant effects on hypothalamic gene expression of receptors for leptin, CCK₁ and GLP-1. These studies underscore the potential of (pGlu-Gln)-CCK-8 for the treatment of obesity-diabetes and suggest modulation of NPY and melanocortin related pathways may be involved in the observed beneficial effects. © Georg Thieme Verlag KG Stuttgart · New York.

Isolation and characterization of CXC receptor genes in a range of elasmobranchs.

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Goostrey, Anna; Jones, Gareth; Secombes, Christopher J

2005-01-01

The CXC group of chemokines exert their cellular effects via the CXCR group of G-protein coupled receptors. Six CXCR genes have been identified in humans (CXCR1-6), and homologues to some of these have been isolated from a range of vertebrate species. Here we isolate and characterize CXCR genes from a range of elasmobranch species. One CXCR1/2 gene fragment isolated from Scyliorhinus caniculus (lesser spotted catshark), and two CXCR1/2 copies from each of the elasmobranchs, Cetorhinus maximus (basking shark), Carcharodon carcharias (great white shark), and Raja naevus (cuckoo ray), exhibit high similarity to both CXCR1 and CXCR2. The two copies evident in the cuckoo ray and lamniform sharks provide strong evidence of CXCR1/2 lineage specific duplication in rays and sharks. A CXCR fragment isolated from Lamna ditropis (salmon shark) shows high similarity to a range of CXCR4 genes and strong clustering with CXCR4 gene homologues was apparent during phylogenetic reconstruction.

Ovarian steroids regulate tachykinin and tachykinin receptor gene expression in the mouse uterus

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Patak Eva

2009-07-01

Full Text Available Abstract Background In the mouse uterus, pregnancy is accompanied by changes in tachykinin and tachykinin receptor gene expression and in the uterotonic effects of endogenous tachykinins. In this study we have investigated whether changes in tachykinin expression and responses are a result of changes in ovarian steroid levels. Methods We quantified the mRNAs of tachykinins and tachykinin receptors in uteri from ovariectomized mice and studied their regulation in response to estrogen and progesterone using real-time quantitative RT-PCR. Early (3 h and late (24 h responses to estrogen were evaluated and the participation of the estrogen receptors (ER, ERalpha and ERbeta, was analyzed by treating mice with propylpyrazole triol, a selective ERalpha agonist, or diarylpropionitrile, a selective agonist of ERbeta. Results All genes encoding tachykinins (Tac1, Tac2 and Tac4 and tachykinin receptors (Tacr1, Tacr2 and Tacr3 were expressed in uteri from ovariectomized mice. Estrogen increased Tac1 and Tacr1 mRNA after 3 h and decreased Tac1 and Tac4 expression after 24 h. Tac2 and Tacr3 mRNA levels were decreased by estrogen at both 3 and 24 h. Most effects of estrogen were also observed in animals treated with propylpyrazole triol. Progesterone treatment increased the levels of Tac2. Conclusion These results show that the expression of tachykinins and their receptors in the mouse uterus is tightly and differentially regulated by ovarian steroids. Estrogen effects are mainly mediated by ERalpha supporting an essential role for this estrogen receptor in the regulation of the tachykinergic system in the mouse uterus.

Mincle suppresses Toll-like receptor 4 activation.

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Greco, Stephanie H; Mahmood, Syed Kashif; Vahle, Anne-Kristin; Ochi, Atsuo; Batel, Jennifer; Deutsch, Michael; Barilla, Rocky; Seifert, Lena; Pachter, H Leon; Daley, Donnele; Torres-Hernandez, Alejandro; Hundeyin, Mautin; Mani, Vishnu R; Miller, George

2016-07-01

Regulation of Toll-like receptor responses is critical for limiting tissue injury and autoimmunity in both sepsis and sterile inflammation. We found that Mincle, a C-type lectin receptor, regulates proinflammatory Toll-like receptor 4 signaling. Specifically, Mincle ligation diminishes Toll-like receptor 4-mediated inflammation, whereas Mincle deletion or knockdown results in marked hyperresponsiveness to lipopolysaccharide in vitro, as well as overwhelming lipopolysaccharide-mediated inflammation in vivo. Mechanistically, Mincle deletion does not up-regulate Toll-like receptor 4 expression or reduce interleukin 10 production after Toll-like receptor 4 ligation; however, Mincle deletion decreases production of the p38 mitogen-activated protein kinase-dependent inhibitory intermediate suppressor of cytokine signaling 1, A20, and ABIN3 and increases expression of the Toll-like receptor 4 coreceptor CD14. Blockade of CD14 mitigates the increased sensitivity of Mincle(-/-) leukocytes to Toll-like receptor 4 ligation. Collectively, we describe a major role for Mincle in suppressing Toll-like receptor 4 responses and implicate its importance in nonmycobacterial models of inflammation. © Society for Leukocyte Biology.

Haplotypes of the porcine peroxisome proliferator-activated receptor delta gene are associated with backfat thickness

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Blöcker Helmut

2009-11-01

Full Text Available Abstract Background Peroxisome proliferator-activated receptor delta belongs to the nuclear receptor superfamily of ligand-inducible transcription factors. It is a key regulator of lipid metabolism. The peroxisome proliferator-activated receptor delta gene (PPARD has been assigned to a region on porcine chromosome 7, which harbours a quantitative trait locus for backfat. Thus, PPARD is considered a functional and positional candidate gene for backfat thickness. The purpose of this study was to test this candidate gene hypothesis in a cross of breeds that were highly divergent in lipid deposition characteristics. Results Screening for genetic variation in porcine PPARD revealed only silent mutations. Nevertheless, significant associations between PPARD haplotypes and backfat thickness were observed in the F2 generation of the Mangalitsa × Piétrain cross as well as a commercial German Landrace population. Haplotype 5 is associated with increased backfat in F2 Mangalitsa × Piétrain pigs, whereas haplotype 4 is associated with lower backfat thickness in the German Landrace population. Haplotype 4 and 5 carry the same alleles at all but one SNP. Interestingly, the opposite effects of PPARD haplotypes 4 and 5 on backfat thickness are reflected by opposite effects of these two haplotypes on PPAR-δ mRNA levels. Haplotype 4 significantly increases PPAR-δ mRNA levels, whereas haplotype 5 decreases mRNA levels of PPAR-δ. Conclusion This study provides evidence for an association between PPARD and backfat thickness. The association is substantiated by mRNA quantification. Further studies are required to clarify, whether the observed associations are caused by PPARD or are the result of linkage disequilibrium with a causal variant in a neighbouring gene.

The Pseudomonas aeruginosa pirA gene encodes a second receptor for ferrienterobactin and synthetic catecholate analogues.

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Ghysels, Bart; Ochsner, Urs; Möllman, Ute; Heinisch, Lothar; Vasil, Michael; Cornelis, Pierre; Matthijs, Sandra

2005-05-15

Actively secreted iron chelating agents termed siderophores play an important role in the virulence and rhizosphere competence of fluorescent pseudomonads, including Pseudomonas aeruginosa which secretes a high affinity siderophore, pyoverdine, and the low affinity siderophore, pyochelin. Uptake of the iron-siderophore complexes is an active process that requires specific outer membrane located receptors, which are dependent of the inner membrane-associated protein TonB and two other inner membrane proteins, ExbB and ExbC. P. aeruginosa is also capable of using a remarkable variety of heterologous siderophores as sources of iron, apparently by expressing their cognate receptors. Illustrative of this feature are the 32 (of which 28 putative) siderophore receptor genes observed in the P. aeruginosa PAO1 genome. However, except for a few (pyoverdine, pyochelin, enterobactin), the vast majority of P. aeruginosa siderophore receptor genes still remain to be characterized. Ten synthetic iron chelators of catecholate type stimulated growth of a pyoverdine/pyochelin deficient P. aeruginosa PAO1 mutant under condition of severe iron limitation. Null mutants of the 32 putative TonB-dependent siderophore receptor encoding genes engineered in the same genetic background were screened for obvious deficiencies in uptake of the synthetic siderophores, but none showed decreased growth stimulation in the presence of the different siderophores. However, a double knock-out mutant of ferrienterobactin receptor encoding gene pfeA (PA 2688) and pirA (PA0931) failed to be stimulated by 4 of the tested synthetic catecholate siderophores whose chemical structures resemble enterobactin. Ferric-enterobactin also failed to stimulate growth of the double pfeA-pirA mutant although, like its synthetic analogues, it stimulated growth of the corresponding single mutants. Hence, we confirmed that pirA represents a second P. aeruginosa ferric-enterobactin receptor. The example of these two

Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality

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Anastasia K Armeni

2017-02-01

Full Text Available Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA gene polymorphism (rs2234693-PvuII (T→C substitution and oxytocin receptor gene polymorphism (rs53576 (G→A substitution with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20–25 years of age, sexually active, with normal menstrual cycles (28–35 days, were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs, polycystic ovary syndrome (PCOS, thyroid diseases as well as drugs that are implicated in hypothalamus–pituitary–gonadal axis. T allele (wildtype of rs2234693 (PvuII polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic of rs53576 (OXTR polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII and A allele of rs53576 (OXTR polymorphisms (T + A group was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences.

MC1R Genotype and Plumage Colouration in the Zebra Finch (Taeniopygia guttata): Population Structure Generates Artefactual Associations

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Hoffman, J.L.; Krause, E.T.; Lehmann, K.; Krüger, O.

2014-01-01

Polymorphisms at the melanocortin-1 receptor (MC1R) gene have been linked to coloration in many vertebrate species. However, the potentially confounding influence of population structure has rarely been controlled for. We explored the role of the MC1R in a model avian system by sequencing the coding

MC1R and the response of melanocytes to ultraviolet radiation

International Nuclear Information System (INIS)

Rouzaud, Francois; Kadekaro, Ana Luisa; Abdel-Malek, Zalfa A.; Hearing, Vincent J.

2005-01-01

The constitutive color of our skin plays a dramatic role in our photoprotection from solar ultraviolet radiation (UVR) that reaches the Earth and in minimizing DNA damage that gives rise to skin cancer. More than 120 genes have been identified and shown to regulate pigmentation, one of the key genes being melanocortin 1 receptor (MC1R) that encodes the melanocortin 1 receptor (MC1R), a seven-transmembrane G protein-coupled receptor expressed on the surface of melanocytes. Modulation of MC1R function regulates melanin synthesis by melanocytes qualitatively and quantitatively. The MC1R is regulated by the physiological agonists α-melanocyte-stimulating hormone (αMSH) and adrenocorticotropic hormone (ACTH), and antagonist agouti signaling protein (ASP). Activation of the MC1R by binding of an agonist stimulates the synthesis of eumelanin primarily via activation of adenylate cyclase. The significance of cutaneous pigmentation lies in the photoprotective effect of melanin, particularly eumelanin, against sun-induced carcinogenesis. Epidermal melanocytes and keratinocytes respond to UVR by increasing their expression of αMSH and ACTH, which up-regulate the expression of MC1R, and consequently enhance the response of melanocytes to melanocortins. Constitutive skin pigmentation dramatically affects the incidence of skin cancer. The pigmentary phenotype characterized by red hair, fair complexion, inability to tan and tendency to freckle is an independent risk factor for all skin cancers, including melanoma. The MC1R gene is highly polymorphic in human populations, and allelic variation at this locus accounts, to a large extent, for the variation in pigmentary phenotypes and skin phototypes (SPT) in humans. Several allelic variants of the MC1R gene are associated with the red hair and fair skin (RHC) phenotype, and carrying one of these variants is thought to diminish the ability of the epidermis to respond to DNA damage elicited by UVR. The MC1R gene is considered a

MC1R and the response of melanocytes to ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Rouzaud, Francois [Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Building 37, Room 2132, Bethesda, MD 20892 (United States); Kadekaro, Ana Luisa [Department of Dermatology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267 (United States); Abdel-Malek, Zalfa A. [Department of Dermatology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267 (United States); Hearing, Vincent J. [Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Building 37, Room 2132, Bethesda, MD 20892 (United States)]. E-mail: hearingv@nih.gov

2005-04-01

The constitutive color of our skin plays a dramatic role in our photoprotection from solar ultraviolet radiation (UVR) that reaches the Earth and in minimizing DNA damage that gives rise to skin cancer. More than 120 genes have been identified and shown to regulate pigmentation, one of the key genes being melanocortin 1 receptor (MC1R) that encodes the melanocortin 1 receptor (MC1R), a seven-transmembrane G protein-coupled receptor expressed on the surface of melanocytes. Modulation of MC1R function regulates melanin synthesis by melanocytes qualitatively and quantitatively. The MC1R is regulated by the physiological agonists {alpha}-melanocyte-stimulating hormone ({alpha}MSH) and adrenocorticotropic hormone (ACTH), and antagonist agouti signaling protein (ASP). Activation of the MC1R by binding of an agonist stimulates the synthesis of eumelanin primarily via activation of adenylate cyclase. The significance of cutaneous pigmentation lies in the photoprotective effect of melanin, particularly eumelanin, against sun-induced carcinogenesis. Epidermal melanocytes and keratinocytes respond to UVR by increasing their expression of {alpha}MSH and ACTH, which up-regulate the expression of MC1R, and consequently enhance the response of melanocytes to melanocortins. Constitutive skin pigmentation dramatically affects the incidence of skin cancer. The pigmentary phenotype characterized by red hair, fair complexion, inability to tan and tendency to freckle is an independent risk factor for all skin cancers, including melanoma. The MC1R gene is highly polymorphic in human populations, and allelic variation at this locus accounts, to a large extent, for the variation in pigmentary phenotypes and skin phototypes (SPT) in humans. Several allelic variants of the MC1R gene are associated with the red hair and fair skin (RHC) phenotype, and carrying one of these variants is thought to diminish the ability of the epidermis to respond to DNA damage elicited by UVR. The MC1R gene is

Sweet taste receptor gene variation and aspartame taste in primates and other species.

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Li, Xia; Bachmanov, Alexander A; Maehashi, Kenji; Li, Weihua; Lim, Raymond; Brand, Joseph G; Beauchamp, Gary K; Reed, Danielle R; Thai, Chloe; Floriano, Wely B

2011-06-01

Aspartame is a sweetener added to foods and beverages as a low-calorie sugar replacement. Unlike sugars, which are apparently perceived as sweet and desirable by a range of mammals, the ability to taste aspartame varies, with humans, apes, and Old World monkeys perceiving aspartame as sweet but not other primate species. To investigate whether the ability to perceive the sweetness of aspartame correlates with variations in the DNA sequence of the genes encoding sweet taste receptor proteins, T1R2 and T1R3, we sequenced these genes in 9 aspartame taster and nontaster primate species. We then compared these sequences with sequences of their orthologs in 4 other nontasters species. We identified 9 variant sites in the gene encoding T1R2 and 32 variant sites in the gene encoding T1R3 that distinguish aspartame tasters and nontasters. Molecular docking of aspartame to computer-generated models of the T1R2 + T1R3 receptor dimer suggests that species variation at a secondary, allosteric binding site in the T1R2 protein is the most likely origin of differences in perception of the sweetness of aspartame. These results identified a previously unknown site of aspartame interaction with the sweet receptor and suggest that the ability to taste aspartame might have developed during evolution to exploit a specialized food niche.

Microarray evaluation of EP4 receptor-mediated prostaglandin E2 suppression of 3T3-L1 adipocyte differentiation

International Nuclear Information System (INIS)

Sugimoto, Yukihiko; Tsuboi, Hiroaki; Okuno, Yasushi; Tamba, Shigero; Tsuchiya, Soken; Tsujimoto, Gozo; Ichikawa, Atsushi

2004-01-01

Prostaglandin E 2 (PGE 2 ) has been shown to negatively regulate adipogenesis. To explore to what extent PGE 2 inhibits the differentiation of cells to adipocytes and to examine whether its effect could be due to EP4 receptor signaling, we used microarrays to analyze the gene expression profiles of 3T3-L1 cells exposed to a differentiation cocktail supplemented with PGE 2 , AE1-329 (an EP4 agonist), or vehicle. The differentiation-associated responses in genes such as adipocytokines and enzymes related to lipid metabolism were largely weakened upon PGE 2 treatment. In particular, the expression of peroxisome proliferator activated receptor-γ and CCAAT/enhancer binding protein-α, genes playing a central role in adipogenesis, was greatly suppressed. PGE 2 appears to be ineffective to a subclass of insulin target genes such as hexokinase 2 and phosphofructokinase. Similar responses were produced in the differentiation-associated genes upon AE1-329 treatment. These results suggest that PGE 2 inhibits a crucial step of the adipocyte differentiation process by acting on the EP4 receptor in 3T3-L1 cells

Expression of glucocorticoid and progesterone nuclear receptor genes in archival breast cancer tissue

International Nuclear Information System (INIS)

Smith, Robert A; Lea, Rod A; Curran, Joanne E; Weinstein, Stephen R; Griffiths, Lyn R

2003-01-01

Previous studies in our laboratory have shown associations of specific nuclear receptor gene variants with sporadic breast cancer. In order to investigate these findings further, we conducted the present study to determine whether expression levels of the progesterone and glucocorticoid nuclear receptor genes vary in different breast cancer grades. RNA was extracted from paraffin-embedded archival breast tumour tissue and converted into cDNA. Sample cDNA underwent PCR using labelled primers to enable quantitation of mRNA expression. Expression data were normalized against the 18S ribosomal gene multiplex and analyzed using analysis of variance. Analysis of variance indicated a variable level of expression of both genes with regard to breast cancer grade (P = 0.00033 for glucocorticoid receptor and P = 0.023 for progesterone receptor). Statistical analysis indicated that expression of the progesterone nuclear receptor is elevated in late grade breast cancer tissue

Gene specific actions of thyroid hormone receptor subtypes.

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Jean Z Lin

Full Text Available There are two homologous thyroid hormone (TH receptors (TRs α and β, which are members of the nuclear hormone receptor (NR family. While TRs regulate different processes in vivo and other highly related NRs regulate distinct gene sets, initial studies of TR action revealed near complete overlaps in their actions at the level of individual genes. Here, we assessed the extent that TRα and TRβ differ in target gene regulation by comparing effects of equal levels of stably expressed exogenous TRs +/- T(3 in two cell backgrounds (HepG2 and HeLa. We find that hundreds of genes respond to T(3 or to unliganded TRs in both cell types, but were not able to detect verifiable examples of completely TR subtype-specific gene regulation. TR actions are, however, far from identical and we detect TR subtype-specific effects on global T(3 response kinetics in HepG2 cells and many examples of TR subtype specificity at the level of individual genes, including effects on magnitude of response to TR +/- T(3, TR regulation patterns and T(3 dose response. Cycloheximide (CHX treatment confirms that at least some differential effects involve verifiable direct TR target genes. TR subtype/gene-specific effects emerge in the context of widespread variation in target gene response and we suggest that gene-selective effects on mechanism of TR action highlight differences in TR subtype function that emerge in the environment of specific genes. We propose that differential TR actions could influence physiologic and pharmacologic responses to THs and selective TR modulators (STRMs.

Gene expression profiling of the androgen receptor antagonists flutamide and vinclozolin in zebrafish (Danio rerio) gonads

International Nuclear Information System (INIS)

Martinovic-Weigelt, Dalma; Wang Ronglin; Villeneuve, Daniel L.; Bencic, David C.; Lazorchak, Jim; Ankley, Gerald T.

2011-01-01

The studies presented in this manuscript focus on characterization of transcriptomic responses to anti-androgens in zebrafish (Danio rerio). Research on the effects of anti-androgens in fish has been characterized by a heavy reliance on apical endpoints, and molecular mechanisms of action (MOA) of anti-androgens remain poorly elucidated. In the present study, we examined effects of a short term exposure (24-96 h) to the androgen receptor antagonists flutamide (FLU) and vinclozolin (VZ) on gene expression in gonads of sexually mature zebrafish, using commercially available zebrafish oligonucleotide microarrays (4 x 44 K platform). We found that VZ and FLU potentially impact reproductive processes via multiple pathways related to steroidogenesis, spermatogenesis, and fertilization. Observed changes in gene expression often were shared by VZ and FLU, as demonstrated by overlap in differentially-expressed genes and enrichment of several common key pathways including: (1) integrin and actin signaling, (2) nuclear receptor 5A1 signaling, (3) fibroblast growth factor receptor signaling, (4) polyamine synthesis, and (5) androgen synthesis. This information should prove useful to elucidating specific mechanisms of reproductive effects of anti-androgens in fish, as well as developing biomarkers for this important class of endocrine-active chemicals.

Gene expression profiling of the androgen receptor antagonists flutamide and vinclozolin in zebrafish (Danio rerio) gonads

Energy Technology Data Exchange (ETDEWEB)

Martinovic-Weigelt, Dalma, E-mail: dalma@stthomas.edu [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States); University of St. Thomas, 2115 Summit Ave, Saint Paul, MN 55105 (United States); Wang Ronglin [US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26W. Martin Luther King Dr., Cincinnati, OH 45268 (United States); Villeneuve, Daniel L. [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States); Bencic, David C.; Lazorchak, Jim [US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26W. Martin Luther King Dr., Cincinnati, OH 45268 (United States); Ankley, Gerald T. [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States)

2011-01-25

The studies presented in this manuscript focus on characterization of transcriptomic responses to anti-androgens in zebrafish (Danio rerio). Research on the effects of anti-androgens in fish has been characterized by a heavy reliance on apical endpoints, and molecular mechanisms of action (MOA) of anti-androgens remain poorly elucidated. In the present study, we examined effects of a short term exposure (24-96 h) to the androgen receptor antagonists flutamide (FLU) and vinclozolin (VZ) on gene expression in gonads of sexually mature zebrafish, using commercially available zebrafish oligonucleotide microarrays (4 x 44 K platform). We found that VZ and FLU potentially impact reproductive processes via multiple pathways related to steroidogenesis, spermatogenesis, and fertilization. Observed changes in gene expression often were shared by VZ and FLU, as demonstrated by overlap in differentially-expressed genes and enrichment of several common key pathways including: (1) integrin and actin signaling, (2) nuclear receptor 5A1 signaling, (3) fibroblast growth factor receptor signaling, (4) polyamine synthesis, and (5) androgen synthesis. This information should prove useful to elucidating specific mechanisms of reproductive effects of anti-androgens in fish, as well as developing biomarkers for this important class of endocrine-active chemicals.

Self-focusing therapeutic gene delivery with intelligent gene vector swarms: intra-swarm signalling through receptor transgene expression in targeted cells.

Science.gov (United States)

Tolmachov, Oleg E

2015-01-01

Gene delivery in vivo that is tightly focused on the intended target cells is essential to maximize the benefits of gene therapy and to reduce unwanted side-effects. Cell surface markers are immediately available for probing by therapeutic gene vectors and are often used to direct gene transfer with these vectors to specific target cell populations. However, it is not unusual for the choice of available extra-cellular markers to be too scarce to provide a reliable definition of the desired therapeutically relevant set of target cells. Therefore, interrogation of intra-cellular determinants of cell-specificity, such as tissue-specific transcription factors, can be vital in order to provide detailed cell-guiding information to gene vector particles. An important improvement in cell-specific gene delivery can be achieved through auto-buildup in vector homing efficiency using intelligent 'self-focusing' of swarms of vector particles on target cells. Vector self-focusing was previously suggested to rely on the release of diffusible chemo-attractants after a successful target-specific hit by 'scout' vector particles. I hypothesize that intelligent self-focusing behaviour of swarms of cell-targeted therapeutic gene vectors can be accomplished without the employment of difficult-to-use diffusible chemo-attractants, instead relying on the intra-swarm signalling through cells expressing a non-diffusible extra-cellular receptor for the gene vectors. In the proposed model, cell-guiding information is gathered by the 'scout' gene vector particles, which: (1) attach to a variety of cells via a weakly binding (low affinity) receptor; (2) successfully facilitate gene transfer into these cells; (3) query intra-cellular determinants of cell-specificity with their transgene expression control elements and (4) direct the cell-specific biosynthesis of a vector-encoded strongly binding (high affinity) cell-surface receptor. Free members of the vector swarm loaded with therapeutic cargo

Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

International Nuclear Information System (INIS)

Teodorov, E.; Ferrari, M.F.R.; Fior-Chadi, D.R.; Camarini, R.; Felício, L.F.

2012-01-01

The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

Energy Technology Data Exchange (ETDEWEB)

Teodorov, E. [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Paulo, SP (Brazil); Ferrari, M.F.R. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Fior-Chadi, D.R. [Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Camarini, R. [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Felício, L.F. [Departamento de Patologia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP (Brazil)

2012-06-01

The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

Directory of Open Access Journals (Sweden)

E. Teodorov

2012-10-01

Full Text Available The periaqueductal gray (PAG has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc or 0.9% saline (up to 1 mL/kg and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05 because a lower percentage of kappa group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR. A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05 and lactating female rats (P < 0.01, with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in

Intracellular insulin-receptor dissociation and segregation in a rat fibroblast cell line transfected with a human insulin receptor gene

International Nuclear Information System (INIS)

Levy, J.R.; Olefsky, J.M.

1988-01-01

The cellular processing of insulin and insulin receptors was studied using a rat fibroblast cell line that had been transfected with a normal human insulin receptor gene, expressing approximately 500 times the normal number of native fibroblasts insulin receptors. These cells bind and internalize insulin normally. Biochemically assays based on the selective precipitation by polyethylene glycol of intact insulin-receptor complexes but not of free intracellular insulin were developed to study the time course of intracellular insulin-receptor dissociation. Fibroblasts were incubated with radiolabeled insulin at 4 0 C, and internalization of insulin-receptor complexes was initiated by warming the cells to 37 0 C. Within 2 min, 90% of the internalized radioactivity was composed of intact insulin-receptor complexes. The dissociation of insulin from internalized insulin-receptor complexes was markedly inhibited by monensin and chloroquine. Furthermore, chloroquine markedly increased the number of cross-linkable intracellular insulin-receptor complexes, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography. These findings suggest that acidification of intracellular vesicles is responsible for insulin-receptor dissociation. Physical segregation of dissociated intracellular insulin from its receptor was monitored. The results are consistent with the view that segregation of insulin and receptor occurs 5-10 min after initiation of dissociation. These studies demonstrate the intracellular itinerary of insulin-receptor complexes, including internalization, dissociation of insulin from the internalized receptor within an acidified compartment, segregation of insulin from the receptor, and subsequent ligand degradation

Effects of in vivo exposure to UV filters (4-MBC, OMC, BP-3, 4-HB, OC, OD-PABA) on endocrine signaling genes in the insect Chironomus riparius.

Science.gov (United States)

Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

2013-07-01

There is increasing evidence indicating that several UV filters might have endocrine disruptive effects. Numerous studies have evaluated hormonal effects in vertebrates, mainly reporting estrogenic and androgenic activities in mammals and fishes. There is only limited knowledge about potential endocrine activity in invertebrate hormonal systems. In this work, the effects on endocrine signaling genes of six frequently used UV filters were investigated in Chironomus riparius, a reference organism in aquatic toxicology. The UV filters studied were: octyl-p-methoxycinnamate (OMC) also called 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4-MBC); benzophenone-3 (BP-3); 4-hidroxybenzophenone (4-HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). After in vivo exposure at different dosages, expression levels of the genes coding for the ecdysone receptor (EcR), the ultraspiracle (usp, ortholog of the RXR) and the estrogen-related receptor (ERR) were quantified by Real Time PCR. The EcR gene was significantly upregulated by 4-MBC, OMC/EHMC and OD-PABA, with a dose-related response following 24h exposure. In contrast, the benzophenones, BP-3 and 4-HB, as well as OC did not alter this gene at the same exposure conditions. The transcription profiles of the usp and ERR genes were not significantly affected, except for BP-3 that inhibited the usp gene at the highest concentration. To our knowledge, this is the first experimental evidence in invertebrates of a direct effect of UV filters on endocrine-related genes, and is consistent with the known effects on vertebrate hormonal receptor genes. The capability of 4-MBC, OMC/EHMC and OD-PABA to stimulate the expression of the ecdysone receptor, a key transcription factor for the ecdysone-genomic response in arthropods, suggests the possibility of a broad and long-term effect on this hormonal pathway. These findings strengthen the need for further research about the ecotoxicological implications

Global analysis of gene expression mediated by OX1 orexin receptor signaling in a hypothalamic cell line.

Directory of Open Access Journals (Sweden)

Eric Koesema

Full Text Available The orexins and their cognate G-protein coupled receptors have been widely studied due to their associations with various behaviors and cellular processes. However, the detailed downstream signaling cascades that mediate these effects are not completely understood. We report the generation of a neuronal model cell line that stably expresses the OX1 orexin receptor (OX1 and an RNA-Seq analysis of changes in gene expression seen upon receptor activation. Upon treatment with orexin, several families of related transcription factors are transcriptionally regulated, including the early growth response genes (Egr, the Kruppel-like factors (Klf, and the Nr4a subgroup of nuclear hormone receptors. Furthermore, some of the transcriptional effects observed have also been seen in data from in vivo sleep deprivation microarray studies, supporting the physiological relevance of the data set. Additionally, inhibition of one of the most highly regulated genes, serum and glucocorticoid-regulated kinase 1 (Sgk1, resulted in the diminished orexin-dependent induction of a subset of genes. These results provide new insight into the molecular signaling events that occur during OX1 signaling and support a role for orexin signaling in the stimulation of wakefulness during sleep deprivation studies.

Statistical and biological gene-lifestyle interactions of MC4R and FTO with diet and physical activity on obesity: new effects on alcohol consumption.

Directory of Open Access Journals (Sweden)

Dolores Corella

Full Text Available BACKGROUND: Fat mass and obesity (FTO and melanocortin-4 receptor (MC4R and are relevant genes associated with obesity. This could be through food intake, but results are contradictory. Modulation by diet or other lifestyle factors is also not well understood. OBJECTIVE: To investigate whether MC4R and FTO associations with body-weight are modulated by diet and physical activity (PA, and to study their association with alcohol and food intake. METHODS: Adherence to Mediterranean diet (AdMedDiet and physical activity (PA were assessed by validated questionnaires in 7,052 high cardiovascular risk subjects. MC4R rs17782313 and FTO rs9939609 were determined. Independent and joint associations (aggregate genetic score as well as statistical and biological gene-lifestyle interactions were analyzed. RESULTS: FTO rs9939609 was associated with higher body mass index (BMI, waist circumference (WC and obesity (P<0.05 for all. A similar, but not significant trend was found for MC4R rs17782313. Their additive effects (aggregate score were significant and we observed a 7% per-allele increase of being obese (OR=1.07; 95%CI 1.01-1.13. We found relevant statistical interactions (P<0.05 with PA. So, in active individuals, the associations with higher BMI, WC or obesity were not detected. A biological (non-statistical interaction between AdMedDiet and rs9939609 and the aggregate score was found. Greater AdMedDiet in individuals carrying 4 or 3-risk alleles counterbalanced their genetic predisposition, exhibiting similar BMI (P=0.502 than individuals with no risk alleles and lower AdMedDiet. They also had lower BMI (P=0.021 than their counterparts with low AdMedDiet. We did not find any consistent association with energy or macronutrients, but found a novel association between these polymorphisms and lower alcohol consumption in variant-allele carriers (B+/-SE: -0.57+/-0.16 g/d per-score-allele; P=0.001. CONCLUSION: Statistical and biological interactions with PA

Histamine H4 receptor in oral lichen planus.

Science.gov (United States)

Salem, A; Al-Samadi, A; Stegajev, V; Stark, H; Häyrinen-Immonen, R; Ainola, M; Hietanen, J; Konttinen, Y T

2015-04-01

Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P = 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts. Healthy oral epithelial cells are equipped with H4 R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4 R. Cell culture experiments suggest a rapid H4 R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4 R synthesis. H4 R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Differential expression of appetite-regulating genes in avian models of anorexia and obesity.

Science.gov (United States)

Yi, J; Yuan, J; Gilbert, E R; Siegel, P B; Cline, M A

2017-08-01

Chickens from lines that have been selected for low (LWS) or high (HWS) juvenile body weight for more than 57 generations provide a unique model by which to research appetite regulation. The LWS display different severities of anorexia, whereas all HWS become obese. In the present study, we measured mRNA abundance of various factors in appetite-associated nuclei in the hypothalamus. The lateral hypothalamus (LHA), paraventricular nucleus (PVN), ventromedial hypothalamus (VMH), dorsomedial nucleus (DMN) and arcuate nucleus (ARC) were collected from 5 day-old chicks that were fasted for 180 minutes or provided with continuous access to food. Fasting increased neuropeptide Y receptor subtype 1 (NPYR1) mRNA in the LHA and c-Fos in the VMH, at the same time as decreasing c-Fos in the LHA, neuropeptide Y receptor subtype 5 and ghrelin in the PVN, and neuropeptide Y receptor subtype 2 in the ARC. Fasting increased melanocortin receptor subtype 3 (MC3R) expression in the DMN and NPY in the ARC of LWS but not HWS chicks. Expression of NPY was greater in LWS than HWS in the DMN. neuropeptide Y receptor subtype 5 mRNA was greater in LWS than HWS in the LHA, PVN and ARC. Expression of orexin was greater in LWS than HWS in the LHA. There was greater expression of NPYR1, melanocortin receptor subtype 4 and cocaine- and amphetamine-regulated transcript in HWS than LWS and mesotocin in LWS than HWS in the PVN. In the ARC, agouti-related peptide and MC3R were greater in LWS than HWS and, in the VMH, orexin receptor 2 and leptin receptor were greater in LWS than HWS. Greater mesotocin in the PVN, orexin in the LHA and ORXR2 in the VMH of LWS may contribute to their increased sympathetic tone and anorexic phenotype. The results of the present study also suggest that an increased hypothalamic anorexigenic tone in the LWS over-rides orexigenic factors such as NPY and AgRP that were more highly expressed in LWS than HWS in several nuclei. Published 2017. This article is a U

Dopamine receptor gene d4 polymorphisms and early sexual onset: gender and environmental moderation in a sample of african-american youth.

Science.gov (United States)

Kogan, Steven M; Lei, Man-Kit; Beach, Steven R H; Brody, Gene H; Windle, Michael; Lee, Sunbok; MacKillop, James; Chen, Yi-Fu

2014-08-01

Early sexual onset and its consequences disproportionately affect African-American youth, particularly male youth. The dopamine receptor D4 gene (DRD4) has been linked to sexual activity and other forms of appetitive behavior, particularly for male youth and in combination with environmental factors (gene × environment [G × E] effects). The differential susceptibility perspective suggests that DRD4 may exert this effect by amplifying the effects of both positive and negative environments. We hypothesized that DRD4 status would amplify the influence of both positive and negative neighborhood environments on early sexual onset among male, but not female, African-Americans. Hypotheses were tested with self-report, biospecimen, and census data from five prospective studies of male and female African-American youth in rural Georgia communities, N = 1,677. Early sexual onset was defined as intercourse before age 14. No significant G × E findings emerged for female youth. Male youth with a DRD4 long allele were more likely than those with two DRD4 short alleles to report early sexual onset in negative community environments and not to report early onset in positive community environments. Dopaminergic regulation of adolescent sexual behaviors may operate differently by gender. DRD4 operated as an environmental amplification rather than a vulnerability factor. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Clone and expression of human transferrin receptor gene: a marker gene for magnetic resonance imaging

International Nuclear Information System (INIS)

Li Li; Liu Lizhi; Lv Yanchun; Liu Xuewen; Cui Chunyan; Wu Peihong; Liu Qicai; Ou Shanxing

2007-01-01

Objective: To clone human transferrin receptor (hTfR) gene and construct expression vector producing recombination protein. Methods: Human transferrin receptor gene cDNA was amplified by RT-PCR from human embryonic liver and lung tissue. Recombinant pcDNA3-hTfR and pEGFP-Cl-hTfR plasmids were constructed and confirmed by DNA sequencing. These plasmids were stably transfected into the HEK293 cells. The protein expression in vitro was confirmed by Western Blot. The efficiency of expression and the location of hTfR were also investigated by fluorescence microscopy and confocal fluorescence microscopy. Results: The full length cDNA of hTfR gene (2332 bp) was cloned and sequenced. The hTfR (190 000) was overexpressed in transfected HEK293 cells by Western blot analysis. Fluorescence micrographs displayed that the hTfR was expressed at high level and located predominantly in the cell surface. Conclusions: Human transferrin receptor (hTfR) gene has been successfully cloned and obtained high-level expression in HEK293 cells, and the recombination protein of hTfR distributed predominantly in the cell membrane. (authors)

Transcriptional regulation of the human Liver X Receptor α gene by Hepatocyte Nuclear Factor 4α

Energy Technology Data Exchange (ETDEWEB)

Theofilatos, Dimitris; Anestis, Aristomenis [University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, 71003, Crete (Greece); Hashimoto, Koshi [Department of Preemptive Medicine and Metabolism, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-city, Tokyo, 113-8510 (Japan); Kardassis, Dimitris, E-mail: kardasis@imbb.forth.gr [University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, 71003, Crete (Greece)

2016-01-15

Liver X Receptors (LXRs) are sterol-activated transcription factors that play major roles in cellular cholesterol homeostasis, HDL biogenesis and reverse cholesterol transport. The aim of the present study was to investigate the mechanisms that control the expression of the human LXRα gene in hepatic cells. A series of reporter plasmids containing consecutive 5′ deletions of the hLXRα promoter upstream of the luciferase gene were constructed and the activity of each construct was measured in HepG2 cells. This analysis showed that the activity of the human LXRα promoter was significantly reduced by deleting the −111 to −42 region suggesting the presence of positive regulatory elements in this short proximal fragment. Bioinformatics data including motif search and ChIP-Seq revealed the presence of a potential binding motif for Hepatocyte Nuclear Factor 4 α (HNF-4α) in this area. Overexpression of HNF-4α in HEK 293T cells increased the expression of all LXRα promoter constructs except −42/+384. In line, silencing the expression of endogenous HNF-4α in HepG2 cells was associated with reduced LXRα protein levels and reduced activity of the −111/+384 LXRα promoter but not of the −42/+384 promoter. Using ChiP assays in HepG2 cells combined with DNAP assays we mapped the novel HNF-4α specific binding motif (H4-SBM) in the −50 to −40 region of the human LXRα promoter. A triple mutation in this H4-SBM abolished HNF-4α binding and reduced the activity of the promoter to 65% relative to the wild type. Furthermore, the mutant promoter could not be transactivated by HNF-4α. In conclusion, our data indicate that HNF-4α may have a wider role in cell and plasma cholesterol homeostasis by controlling the expression of LXRα in hepatic cells. - Highlights: • The human LXRα promoter contains a HNF-4α specific binding motif in the proximal −50/−40 region. • Mutations in this motif abolished HNF4α binding and transactivation of the h

Transcriptional regulation of the human Liver X Receptor α gene by Hepatocyte Nuclear Factor 4α

International Nuclear Information System (INIS)

Theofilatos, Dimitris; Anestis, Aristomenis; Hashimoto, Koshi; Kardassis, Dimitris

2016-01-01

Liver X Receptors (LXRs) are sterol-activated transcription factors that play major roles in cellular cholesterol homeostasis, HDL biogenesis and reverse cholesterol transport. The aim of the present study was to investigate the mechanisms that control the expression of the human LXRα gene in hepatic cells. A series of reporter plasmids containing consecutive 5′ deletions of the hLXRα promoter upstream of the luciferase gene were constructed and the activity of each construct was measured in HepG2 cells. This analysis showed that the activity of the human LXRα promoter was significantly reduced by deleting the −111 to −42 region suggesting the presence of positive regulatory elements in this short proximal fragment. Bioinformatics data including motif search and ChIP-Seq revealed the presence of a potential binding motif for Hepatocyte Nuclear Factor 4 α (HNF-4α) in this area. Overexpression of HNF-4α in HEK 293T cells increased the expression of all LXRα promoter constructs except −42/+384. In line, silencing the expression of endogenous HNF-4α in HepG2 cells was associated with reduced LXRα protein levels and reduced activity of the −111/+384 LXRα promoter but not of the −42/+384 promoter. Using ChiP assays in HepG2 cells combined with DNAP assays we mapped the novel HNF-4α specific binding motif (H4-SBM) in the −50 to −40 region of the human LXRα promoter. A triple mutation in this H4-SBM abolished HNF-4α binding and reduced the activity of the promoter to 65% relative to the wild type. Furthermore, the mutant promoter could not be transactivated by HNF-4α. In conclusion, our data indicate that HNF-4α may have a wider role in cell and plasma cholesterol homeostasis by controlling the expression of LXRα in hepatic cells. - Highlights: • The human LXRα promoter contains a HNF-4α specific binding motif in the proximal −50/−40 region. • Mutations in this motif abolished HNF4α binding and transactivation of the h

Proneoplastic effects of PGE2 mediated by EP4 receptor in colorectal cancer.

LENUS (Irish Health Repository)

Doherty, Glen A

2009-01-01

BACKGROUND: Prostaglandin E2 (PGE2) is the major product of Cyclooxygenase-2 (COX-2) in colorectal cancer (CRC). We aimed to assess PGE2 cell surface receptors (EP 1-4) to examine the mechanisms by which PGE2 regulates tumour progression. METHODS: Gene expression studies were performed by quantitative RT-PCR. Cell cycle was analysed by flow cytometry with cell proliferation quantified by BrdU incorporation measured by enzyme immunoassay. Immunohistochemistry was employed for expression studies on formalin fixed paraffin embedded tumour tissue. RESULTS: EP4 was the most abundant subtype of PGE2 receptor in HT-29 and HCA7 cells (which show COX-2 dependent PGE2 generation) and was consistently the most abundant transcript in human colorectal tumours (n = 8) by qRT-PCR (ANOVA, p = 0.01). G0\\/G1 cell cycle arrest was observed in HT-29 cells treated with SC-236 5 microM (selective COX-2 inhibitor) for 24 hours (p = 0.02), an effect abrogated by co-incubation with PGE2 (1 microM). G0\\/G1 arrest was also seen with a specific EP4 receptor antagonist (EP4A, L-161982) (p = 0.01). Treatment of HT-29 cells with either SC-236 or EP4A caused reduction in intracellular cAMP (ANOVA, p = 0.01). Early induction in p21WAF1\\/CIP1 expression (by qRT-PCR) was seen with EP4A treatment (mean fold increase 4.4, p = 0.04) while other genes remained unchanged. Similar induction in p21WAF1\\/CIP1 was also seen with PD153025 (1 microM), an EGFR tyrosine kinase inhibitor, suggesting EGFR transactivation by EP4 as a potential mechanism. Additive inhibition of HCA7 proliferation was observed with the combination of SC-236 and neutralising antibody to amphiregulin (AR), a soluble EGFR ligand. Concordance in COX-2 and AR localisation in human colorectal tumours was noted. CONCLUSION: COX-2 regulates cell cycle transition via EP4 receptor and altered p21WAF1\\/CIP1 expression. EGFR pathways appear important. Specific targeting of the EP4 receptor or downstream targets may offer a safer alternative

Dopamine D4 Receptor Gene and Religious Affiliation Correlate with Dictator Game Altruism in Males and not Females: Evidence for Gender-sensitive Gene x Culture Interaction

Directory of Open Access Journals (Sweden)

Yushi eJiang

2015-09-01

Full Text Available On a large sample of 2288 Han Chinese undergraduates, we investigated how religion and DRD4 are related to human altruistic giving behavior as measured with the Andreoni-Miller Dictator Game. This game enables us to clearly specify (non-selfishness, efficiency, and fairness motives for sharing. Participants were further classified into religious categories (Christian, Buddhist-Tao, and No Religion based on self-reports, and genotyped for the dopamine D4 receptor (DRD4 gene exon III VNTR. Our analysis revealed a significant interaction between religion and DRD4 correlated with giving behavior solely among males: Whereas no significant association between religion and sharing decisions was observed in the majority 4R/4R genotype group, a significant difference in giving behavior between Christian and non-Christian males was seen in the non-4R/4R group, with Christian men being overall more altruistic (less selfish and fairer than non-Christian men. These results support the vantage sensitivity hypothesis regarding DRD4 that the non-4R/4R ‘susceptibility’ genotype is more responsive to a positive environment provided by some religions.

Association of vitamin D receptor and estrogen receptor-α gene polymorphism with peak bone mass and bone size in Chinese women

Institute of Scientific and Technical Information of China (English)

Yue-juan QIN; Zhen-lin ZHANG; Qi-ren HUANG; Jin-wei HE; Yun-qiu HU; Qi ZHOU; Jing-hui LU; Miao LI; Yu-juan LIU

2004-01-01

AIM: To investigate if vitamin D receptor (VDR) gene Apa I polymorphism and estrogen receptor-α (ER-α) gene Pvu II, Xba I polymorphisms are related to bone mineral density (BMD), bone mineral content (BMC) and bone size in premenopausal Chinese women. METHODS: The VDR Apa I genotype and ER-α Pvu II, Xba I genotype were determined by PCR-restriction fragment length polymorphism (RFLP) in 493 unrelated healthy women aged 20-40 years of Hah nationality in Shanghai city. BMD (g/cm2), BMC (g), and bone areal size (BAS, cm2) at lumbar spine 1-4 (L1-4) and proximal femur (femoral neck, trochanter and Ward's triangle) were measured by duel-energy X-ray absorptionmetry. RESULTS: All allele frequencies did not deviate from Hardy-Weinberg equilibrium. After phenotypes were adjusted for age, height, and weight, a significant association was found between VDR Apa I genotype and BMC variation at L1-4 and Ward's triangle (P<0.05), but not in BMD or BAS at lumbar spine and proximal femur.ER-α Pvu II, Xba I genotype was not related to BMC, BMD, and BAS at all sites. CONCLUSION: The study suggested that Apa I polymorphism in VDR gene may influence on attainment and maintenance of peak bone mass in premenopausal Chinese women.