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Sample records for activator receptor affects

  1. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    Nine structurally different polycyclic aromatic hydrocarbons (PAHs) were tested for their ability to either agonize or antagonize the human androgen receptor (hAR) in a sensitive reporter gene assay based on CHO cells transiently cotransfected with a hAR vector and an MMTV-LUC vector. Benz...

  2. TAM receptors affect adult brain neurogenesis by negative regulation of microglial cell activation.

    Science.gov (United States)

    Ji, Rui; Tian, Shifu; Lu, Helen J; Lu, Qingjun; Zheng, Yan; Wang, Xiaomin; Ding, Jixiang; Li, Qiutang; Lu, Qingxian

    2013-12-15

    TAM tyrosine kinases play multiple functional roles, including regulation of the target genes important in homeostatic regulation of cytokine receptors or TLR-mediated signal transduction pathways. In this study, we show that TAM receptors affect adult hippocampal neurogenesis and loss of TAM receptors impairs hippocampal neurogenesis, largely attributed to exaggerated inflammatory responses by microglia characterized by increased MAPK and NF-κB activation and elevated production of proinflammatory cytokines that are detrimental to neuron stem cell proliferation and neuronal differentiation. Injection of LPS causes even more severe inhibition of BrdU incorporation in the Tyro3(-/-)Axl(-/-)Mertk(-/-) triple-knockout (TKO) brains, consistent with the LPS-elicited enhanced expression of proinflammatory mediators, for example, IL-1β, IL-6, TNF-α, and inducible NO synthase, and this effect is antagonized by coinjection of the anti-inflammatory drug indomethacin in wild-type but not TKO brains. Conditioned medium from TKO microglia cultures inhibits neuron stem cell proliferation and neuronal differentiation. IL-6 knockout in Axl(-/-)Mertk(-/-) double-knockout mice overcomes the inflammatory inhibition of neurogenesis, suggesting that IL-6 is a major downstream neurotoxic mediator under homeostatic regulation by TAM receptors in microglia. Additionally, autonomous trophic function of the TAM receptors on the proliferating neuronal progenitors may also promote progenitor differentiation into immature neurons.

  3. Motor activity affects adult skeletal muscle re-innervation acting via tyrosine kinase receptors.

    Science.gov (United States)

    Sartini, Stefano; Bartolini, Fanny; Ambrogini, Patrizia; Betti, Michele; Ciuffoli, Stefano; Lattanzi, Davide; Di Palma, Michael; Cuppini, Riccardo

    2013-05-01

    Recently, muscle expression of brain-derived neurotrophic factor (BDNF) mRNA and protein under activity control has been reported. BDNF is a neurotrophin known to be involved in axon sprouting in the CNS. Hence, we set out to study the effect of chronic treadmill mid-intensity running on adult rat muscle re-innervation, and to explore the involvement of BDNF and tropomyosin-related kinase (Trk) receptors. After nerve crush, muscle re-innervation was evaluated using intracellular recordings, tension recordings, immunostaining and Western blot analyses. An enhanced muscle multiple innervation was found in running rats that was fully reversed to control values blocking Trk receptors or interrupting the running activity. An increase in muscle multiple innervation was also found in sedentary rats treated with a selective TrkB receptor agonist. The expression of TrkB receptors by intramuscular axons was demonstrated, and increased muscle expression of BDNF was found in running animals. The increase in muscle multiple innervation was consistent with the faster muscle re-innervation that we found in running animals. We conclude that, when regenerating axons contact muscle cells, muscle activity progressively increases modulating BDNF and possibly other growth factors, which in turn, acting via Trk receptors, induce axon sprouting to re-innervate skeletal muscle.

  4. The Identification of Novel Protein-Protein Interactions in Liver that Affect Glucagon Receptor Activity.

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    Junfeng Han

    Full Text Available Glucagon regulates glucose homeostasis by controlling glycogenolysis and gluconeogenesis in the liver. Exaggerated and dysregulated glucagon secretion can exacerbate hyperglycemia contributing to type 2 diabetes (T2D. Thus, it is important to understand how glucagon receptor (GCGR activity and signaling is controlled in hepatocytes. To better understand this, we sought to identify proteins that interact with the GCGR to affect ligand-dependent receptor activation. A Flag-tagged human GCGR was recombinantly expressed in Chinese hamster ovary (CHO cells, and GCGR complexes were isolated by affinity purification (AP. Complexes were then analyzed by mass spectrometry (MS, and protein-GCGR interactions were validated by co-immunoprecipitation (Co-IP and Western blot. This was followed by studies in primary hepatocytes to assess the effects of each interactor on glucagon-dependent glucose production and intracellular cAMP accumulation, and then in immortalized CHO and liver cell lines to further examine cell signaling. Thirty-three unique interactors were identified from the AP-MS screening of GCGR expressing CHO cells in both glucagon liganded and unliganded states. These studies revealed a particularly robust interaction between GCGR and 5 proteins, further validated by Co-IP, Western blot and qPCR. Overexpression of selected interactors in mouse hepatocytes indicated that two interactors, LDLR and TMED2, significantly enhanced glucagon-stimulated glucose production, while YWHAB inhibited glucose production. This was mirrored with glucagon-stimulated cAMP production, with LDLR and TMED2 enhancing and YWHAB inhibiting cAMP accumulation. To further link these interactors to glucose production, key gluconeogenic genes were assessed. Both LDLR and TMED2 stimulated while YWHAB inhibited PEPCK and G6Pase gene expression. In the present study, we have probed the GCGR interactome and found three novel GCGR interactors that control glucagon

  5. Activation of nucleus accumbens NMDA receptors differentially affects appetitive or aversive taste learning and memory

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    Luis eNuñez-Jaramillo

    2012-04-01

    Full Text Available Taste memory depends on motivational and post-ingestional consequences; thus, it can be aversive (e.g., conditioned taste aversion, CTA if a novel, palatable taste is paired with visceral malaise, or it can be appetitive if no intoxication appears after novel taste consumption, and a taste preference is developed. The nucleus accumbens (NAc plays a role in hedonic reactivity to taste stimuli, and recent findings suggest that reward and aversion are differentially encoded by the activity of NAc neurons. The present study examined whether the requirement for NMDA receptors in the NAc core during rewarding appetitive taste learning differs from that during aversive taste conditioning, as well as during retrieval of appetitive versus aversive taste memory, using the taste preference or CTA model, respectively. Bilateral infusions of NMDA (1 μg/μl, 0.5 μl into the NAc core were performed before acquisition or before retrieval of taste preference or CTA. Activation of NMDA receptors before taste preference training or CTA acquisition did not alter memory formation. Furthermore, NMDA injections before aversive taste retrieval had no effect on taste memory; however, 24 h later, CTA extinction was significantly delayed. Also, NMDA injections, made before familiar appetitive memory retrieval, interrupted the development of taste preference and produced a preference delay 24 h later. These results suggest that memory formation for a novel taste produces neurochemical changes in the NAc core that have differential requirements for NMDA receptors during retrieval of appetitive or aversive memory.

  6. Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

    DEFF Research Database (Denmark)

    Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R;

    2007-01-01

    reorganization in mature osteoclasts. INTRODUCTION: Urokinase receptor (uPAR) is actively involved in the regulation of important cell functions, such as proliferation, adhesion, and migration. It was previously shown that the major players in bone remodeling, osteoblasts and osteoclasts, express u...... with other osteoblasts markers. On the resorptive side, the number of osteoclasts formed in vitro from uPAR KO monocytes was decreased. Podosome imaging in uPAR KO osteoclasts revealed a defect in actin ring formation. CONCLUSIONS: The defective proliferation and differentiation of bone cells, coincident...

  7. Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

    DEFF Research Database (Denmark)

    Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R;

    2007-01-01

    reorganization in mature osteoclasts. INTRODUCTION: Urokinase receptor (uPAR) is actively involved in the regulation of important cell functions, such as proliferation, adhesion, and migration. It was previously shown that the major players in bone remodeling, osteoblasts and osteoclasts, express u...... to mechanical tests. UPAR KO calvaria osteoblasts were characterized by proliferation assays, RT-PCR for important proteins secreted during differentiation, and immunoblot for activator protein 1 (AP-1) family members. In vitro osteoclast formation was tested with uPAR KO bone marrow monocytes in the presence...... a proliferative advantage with no difference in apoptosis, higher matrix mineralization, and earlier appearance of alkaline phosphatase (ALP). Surface RANKL expression at different stages of differentiation was not altered. AP-1 components, such as JunB and Fra-1, were upregulated in uPAR KO osteoblasts, along...

  8. Activation of the aryl hydrocarbon receptor affects activation and function of human monocyte-derived dendritic cells.

    Science.gov (United States)

    Wang, C; Ye, Z; Kijlstra, A; Zhou, Y; Yang, P

    2014-08-01

    Aryl hydrocarbon receptor (AhR) is well known for mediating the toxic effects of dioxin-containing pollutants, but has also been shown to be involved in the natural regulation of the immune response. In this study, we investigated the effect of AhR activation by its endogenous ligands 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the differentiation, maturation and function of monocyte-derived DCs in Behçet's disease (BD) patients. In this study, we showed that AhR activation by FICZ and ITE down-regulated the expression of co-stimulatory molecules including human leucocyte antigen D-related (HLA-DR), CD80 and CD86, while it had no effect on the expression of CD83 and CD40 on DCs derived from BD patients and normal controls. Lipopolysaccharide (LPS)-treated dendritic cells (DCs) from active BD patients showed a higher level of interleukin (IL)-1β, IL-6, IL-23 and tumour necrosis factor (TNF)-α production. FICZ or ITE significantly inhibited the production of IL-1β, IL-6, IL-23 and TNF-α, but induced IL-10 production by DCs derived from active BD patients and normal controls. FICZ or ITE-treated DCs significantly inhibited the T helper type 17 (Th17) and Th1 cell response. Activation of AhR either by FICZ or ITE inhibits DC differentiation, maturation and function. Further studies are needed to investigate whether manipulation of the AhR pathway may be used to treat BD or other autoimmune diseases.

  9. A substitution in the ligand binding domain of the porcine glucocorticoid receptor affects activity of the adrenal gland.

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    Eduard Murani

    Full Text Available Glucocorticoids produced in the adrenal cortex under the control of the hypothalamic-pituitary axis play a vital role in the maintenance of basal and stress-related homeostasis and influence health and well-being. To identify loci affecting regulation of the hypothalamic-pituitary-adrenal (HPA axis in the pig we performed a genome-wide association study for two parameters of acute and long-term adrenal activity: plasma cortisol level and adrenal weight. We detected a major quantitative trait locus at the position of the glucocorticoid receptor gene (NR3C1 - a key regulator of HPA axis activity. To determine the causal variant(s, we resequenced the coding region of NR3C1 and found three missense single nucleotide polymorphisms (SNPs. SNP c.1829C>T, leading to a p.Ala610Val substitution in the ligand binding domain, showed large (about 0.6× and 1.2× phenotypic standard deviations for cortisol level and adrenal weight, respectively, and highly significant (2.1E-39≤log10(1/p≤1.7E+0 negative effects on both traits. We were able to replicate the association in three commercial pig populations with different breed origins. We analyzed effects of the p.Ala610Val substitution on glucocorticoid-induced transcriptional activity of porcine glucocorticoid receptor (GR in vitro and determined that the substitution introduced by SNP c.1829C>T increased sensitivity of GR by about two-fold. Finally, we found that non-coding polymorphisms in linkage disequilibrium with SNP c.1829C>T have only a minor effect on the expression of NR3C1 in tissues related to the HPA axis. Our findings provide compelling evidence that SNP c.1829C>T in porcine NR3C1 is a gain-of-function mutation with a major effect on the activity of the adrenal gland. Pigs carrying this SNP could provide a new animal model to study neurobiological and physiological consequences of genetically based GR hypersensitivity and adrenal hypofunction.

  10. Perfluorooctane sulfonate (PFOS) affects hormone receptor activity, steroidogenesis, and expression of endocrine-related genes in vitro and in vivo.

    Science.gov (United States)

    Du, Guizhen; Hu, Jialei; Huang, Hongyu; Qin, Yufeng; Han, Xiumei; Wu, Di; Song, Ling; Xia, Yankai; Wang, Xinru

    2013-02-01

    Perfluorooctane sulfonate (PFOS) is a widespread and persistent chemical in the environment. We investigated the endocrine-disrupting effects of PFOS using a combination of in vitro and in vivo assays. Reporter gene assays were used to detect receptor-mediated (anti-)estrogenic, (anti-)androgenic, and (anti-)thyroid hormone activities. The effect of PFOS on steroidogenesis was assessed both at hormone levels in the supernatant and at expression levels of hormone-induced genes in the H295R cell. A zebrafish-based short-term screening method was developed to detect the effect of PFOS on endocrine function in vivo. The results indicate that PFOS can act as an estrogen receptor agonist and thyroid hormone receptor antagonist. Exposure to PFOS decreased supernatant testosterone (T), increased estradiol (E2) concentrations in H295R cell medium and altered the expression of several genes involved in steroidogenesis. In addition, PFOS increased early thyroid development gene (hhex and pax8) expression in a concentration-dependent manner, decreased steroidogenic enzyme gene (CYP17, CYP19a, CYP19b) expression, and changed the expression pattern of estrogen receptor production genes (esr1, esr2b) after 500 µg/L PFOS treatment in zebrafish embryos. These results indicate that PFOS has the ability to act as an endocrine disruptor both in vitro and in vivo by disrupting the function of nuclear hormone receptors, interfering with steroidogenesis, and altering the expression of endocrine-related genes in zebrafish embryo.

  11. Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

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    Kjeldsen, Lisbeth Stigaard; Ghisari, Mandana; Bonefeld-Jørgensen, Eva Cecilie, E-mail: ebj@mil.au.dk

    2013-10-15

    The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [{sup 3}H]{sub 2}O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks

  12. Cdx2 polymorphism affects the activities of vitamin D receptor in human breast cancer cell lines and human breast carcinomas.

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    Claudio Pulito

    Full Text Available Vitamin D plays a role in cancer development and acts through the vitamin D receptor (VDR. It regulates the action of hormone responsive genes and is involved in cell cycle regulation, differentiation and apoptosis. VDR is a critical component of the vitamin D pathway and different common single nucleotide polymorphisms have been identified. Cdx2 VDR polymorphism can play an important role in breast cancer, modulating the activity of VDR. The objective of this study is to assess the relationship between the Cdx2 VDR polymorphism and the activities of VDR in human breast cancer cell lines and carcinomas breast patients. Cdx2 VDR polymorphism and antiproliferative effects of vitamin D treatment were investigated in a panel of estrogen receptor-positive (MCF7 and T-47D and estrogen receptor-negative (MDA-MB-231, SUM 159PT, SK-BR-3, BT549, MDA-MB-468, HCC1143, BT20 and HCC1954 human breast cancer cell lines. Furthermore, the potential relationship among Cdx2 VDR polymorphism and a number of biomarkers used in clinical management of breast cancer was assessed in an ad hoc set of breast cancer cases. Vitamin D treatment efficacy was found to be strongly dependent on the Cdx2 VDR status in ER-negative breast cancer cell lines tested. In our series of breast cancer cases, the results indicated that patients with variant homozygote AA were associated with bio-pathological characteristics typical of more aggressive tumours, such as ER negative, HER2 positive and G3. Our results may suggest a potential effect of Cdx2 VDR polymorphism on the efficacy of vitamin D treatment in aggressive breast cancer cells (estrogen receptor negative. These results suggest that Cdx2 polymorphism may be a potential biomarker for vitamin D treatment in breast cancer, independently of the VDR receptor expression.

  13. Cdx2 polymorphism affects the activities of vitamin D receptor in human breast cancer cell lines and human breast carcinomas.

    Science.gov (United States)

    Pulito, Claudio; Terrenato, Irene; Di Benedetto, Anna; Korita, Etleva; Goeman, Frauke; Sacconi, Andrea; Biagioni, Francesca; Blandino, Giovanni; Strano, Sabrina; Muti, Paola; Mottolese, Marcella; Falvo, Elisabetta

    2015-01-01

    Vitamin D plays a role in cancer development and acts through the vitamin D receptor (VDR). It regulates the action of hormone responsive genes and is involved in cell cycle regulation, differentiation and apoptosis. VDR is a critical component of the vitamin D pathway and different common single nucleotide polymorphisms have been identified. Cdx2 VDR polymorphism can play an important role in breast cancer, modulating the activity of VDR. The objective of this study is to assess the relationship between the Cdx2 VDR polymorphism and the activities of VDR in human breast cancer cell lines and carcinomas breast patients. Cdx2 VDR polymorphism and antiproliferative effects of vitamin D treatment were investigated in a panel of estrogen receptor-positive (MCF7 and T-47D) and estrogen receptor-negative (MDA-MB-231, SUM 159PT, SK-BR-3, BT549, MDA-MB-468, HCC1143, BT20 and HCC1954) human breast cancer cell lines. Furthermore, the potential relationship among Cdx2 VDR polymorphism and a number of biomarkers used in clinical management of breast cancer was assessed in an ad hoc set of breast cancer cases. Vitamin D treatment efficacy was found to be strongly dependent on the Cdx2 VDR status in ER-negative breast cancer cell lines tested. In our series of breast cancer cases, the results indicated that patients with variant homozygote AA were associated with bio-pathological characteristics typical of more aggressive tumours, such as ER negative, HER2 positive and G3. Our results may suggest a potential effect of Cdx2 VDR polymorphism on the efficacy of vitamin D treatment in aggressive breast cancer cells (estrogen receptor negative). These results suggest that Cdx2 polymorphism may be a potential biomarker for vitamin D treatment in breast cancer, independently of the VDR receptor expression.

  14. Cdx2 Polymorphism Affects the Activities of Vitamin D Receptor in Human Breast Cancer Cell Lines and Human Breast Carcinomas

    Science.gov (United States)

    Di Benedetto, Anna; Korita, Etleva; Goeman, Frauke; Sacconi, Andrea; Biagioni, Francesca; Blandino, Giovanni; Strano, Sabrina; Muti, Paola; Mottolese, Marcella; Falvo, Elisabetta

    2015-01-01

    Vitamin D plays a role in cancer development and acts through the vitamin D receptor (VDR). It regulates the action of hormone responsive genes and is involved in cell cycle regulation, differentiation and apoptosis. VDR is a critical component of the vitamin D pathway and different common single nucleotide polymorphisms have been identified. Cdx2 VDR polymorphism can play an important role in breast cancer, modulating the activity of VDR. The objective of this study is to assess the relationship between the Cdx2 VDR polymorphism and the activities of VDR in human breast cancer cell lines and carcinomas breast patients. Cdx2 VDR polymorphism and antiproliferative effects of vitamin D treatment were investigated in a panel of estrogen receptor-positive (MCF7 and T-47D) and estrogen receptor-negative (MDA-MB-231, SUM 159PT, SK-BR-3, BT549, MDA-MB-468, HCC1143, BT20 and HCC1954) human breast cancer cell lines. Furthermore, the potential relationship among Cdx2 VDR polymorphism and a number of biomarkers used in clinical management of breast cancer was assessed in an ad hoc set of breast cancer cases. Vitamin D treatment efficacy was found to be strongly dependent on the Cdx2 VDR status in ER-negative breast cancer cell lines tested. In our series of breast cancer cases, the results indicated that patients with variant homozygote AA were associated with bio-pathological characteristics typical of more aggressive tumours, such as ER negative, HER2 positive and G3. Our results may suggest a potential effect of Cdx2 VDR polymorphism on the efficacy of vitamin D treatment in aggressive breast cancer cells (estrogen receptor negative). These results suggest that Cdx2 polymorphism may be a potential biomarker for vitamin D treatment in breast cancer, independently of the VDR receptor expression. PMID:25849303

  15. Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity.

    Science.gov (United States)

    Kjeldsen, Lisbeth Stigaard; Ghisari, Mandana; Bonefeld-Jørgensen, Eva Cecilie

    2013-10-15

    The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [(3)H](2)O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks.

  16. Manipulation of D2 receptors with quinpirole and sulpiride affects locomotor activity before spatial behavior of rats in an active place avoidance task.

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    Stuchlik, Ales; Rehakova, Lenka; Rambousek, Lukas; Svoboda, Jan; Vales, Karel

    2007-06-01

    Dopamine-mediated neurotransmission is widely studied with respect to motivation, motor activity and cognitive processes. The aim of the present study was to evaluate the role of D2 receptors in the behavior of rats in the active allothetic place avoidance (AAPA) task. D2 receptor agonist quinpirole and antagonist sulpiride were administered intraperitoneally 20min prior to behavioral testing. Administration of quinpirole led to dose-dependent increase of locomotion; the spatial efficiency was spared across the dose range studied (0.05-1.0mg/kg). In contrast, sulpiride decreased locomotor activity at a dose not influencing spatial efficiency (60mg/kg); the highest dose of sulpiride (100mg/kg) caused a deficit in both locomotor and spatial behaviors. The results suggest a relatively lesser importance of D2 receptors for spatial efficiency in the AAPA task, with a predominant influence of D2 receptor ligands on motor activity.

  17. A risk variant for alcoholism in the NMDA receptor affects amygdala activity during fear conditioning in humans.

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    Cacciaglia, Raffaele; Nees, Frauke; Pohlack, Sebastian T; Ruttorf, Michaela; Winkelmann, Tobias; Witt, Stephanie H; Nieratschker, Vanessa; Rietschel, Marcella; Flor, Herta

    2013-09-01

    People at high risk for alcoholism show deficits in aversive learning, as indicated by impaired electrodermal responses during fear conditioning, a basic form of associative learning that depends on the amygdala. A positive family history of alcohol dependence has also been related to decreased amygdala responses during emotional processing. In the present study we report reduced amygdala activity during the acquisition of conditioned fear in healthy carriers of a risk variant for alcoholism (rs2072450) in the NR2A subunit-containing N-methyl-d-aspartate (NMDA)-receptor. These results indicate that rs2072450 might confer risk for alcohol dependence through deficient fear acquisition indexed by a diminished amygdala response during aversive learning, and provide a neural basis for a weak behavioral inhibition previously documented in individuals at high risk for alcohol dependence. Carriers of the risk variant additionally exhibit dampened insula activation, a finding that further strengthens our data, given the importance of this brain region in fear conditioning.

  18. Diadenosine tetra- and pentaphosphates affect contractility and bioelectrical activity in the rat heart via P2 purinergic receptors.

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    Pustovit, Ksenia B; Kuzmin, Vladislav S; Abramochkin, Denis V

    2016-03-01

    Diadenosine polyphosphates (Ap(n)As) are endogenously produced molecules which have been identified in various tissues of mammalian organism, including myocardium. Ap(n)As contribute to the blood clotting and are also widely accepted as regulators of blood vascular tone. Physiological role of Ap(n)As in cardiac muscle has not been completely elucidated. The present study aimed to investigate the effects of diadenosine tetra- (Ap4A) and penta- (Ap5A) polyphosphates on contractile function and action potential (AP) waveform in rat supraventricular and ventricular myocardium. We have also demonstrated the effects of A4pA and Ap5A in myocardial sleeves of pulmonary veins (PVs), which play a crucial role in genesis of atrial fibrillation. APs were recorded with glass microelectrodes in multicellular myocardial preparations. Contractile activity was measured in isolated Langendorff-perfused rat hearts. Both Ap4A and Ap5A significantly reduced contractility of isolated Langendorff-perfused heart and produced significant reduction of AP duration in left and right auricle, interatrial septum, and especially in right ventricular wall myocardium. Ap(n)As also shortened APs in rat pulmonary veins and therefore may be considered as potential proarrhythmic factors. Cardiotropic effects of Ap4A and Ap5A were strongly antagonized by selective blockers of P2 purine receptors suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), while P1 blocker DPCPX was not effective. We conclude that Ap(n)As may be considered as new class of endogenous cardioinhibitory compounds. P2 purine receptors play the central role in mediation of Ap4A and Ap5A inhibitory effects on electrical and contractile activity in different regions of the rat heart.

  19. Activation of the constitutive androstane receptor inhibits gluconeogenesis without affecting lipogenesis or fatty acid synthesis in human hepatocytes

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    Lynch, Caitlin; Pan, Yongmei; Li, Linhao [Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201 (United States); Heyward, Scott; Moeller, Timothy [Bioreclamation In Vitro Technologies, Baltimore, MD 21227 (United States); Swaan, Peter W. [Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201 (United States); Wang, Hongbing, E-mail: hwang@rx.umaryland.edu [Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201 (United States)

    2014-08-15

    Objective: Accumulating evidence suggests that activation of mouse constitutive androstane receptor (mCAR) alleviates type 2 diabetes and obesity by inhibiting hepatic gluconeogenesis, lipogenesis, and fatty acid synthesis. However, the role of human (h) CAR in energy metabolism is largely unknown. The present study aims to investigate the effects of selective hCAR activators on hepatic energy metabolism in human primary hepatocytes (HPH). Methods: Ligand-based structure–activity models were used for virtual screening of the Specs database ( (www.specs.net)) followed by biological validation in cell-based luciferase assays. The effects of two novel hCAR activators (UM104 and UM145) on hepatic energy metabolism were evaluated in HPH. Results: Real-time PCR and Western blotting analyses reveal that activation of hCAR by UM104 and UM145 significantly repressed the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, two pivotal gluconeogenic enzymes, while exerting negligible effects on the expression of genes associated with lipogenesis and fatty acid synthesis. Functional experiments show that UM104 and UM145 markedly inhibit hepatic synthesis of glucose but not triglycerides in HPH. In contrast, activation of mCAR by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, a selective mCAR activator, repressed the expression of genes associated with gluconeogenesis, lipogenesis, and fatty acid synthesis in mouse primary hepatocytes, which were consistent with previous observations in mouse model in vivo. Conclusion: Our findings uncover an important species difference between hCAR and mCAR in hepatic energy metabolism, where hCAR selectively inhibits gluconeogenesis without suppressing fatty acid synthesis. Implications: Such species selectivity should be considered when exploring CAR as a potential therapeutic target for metabolic disorders. - Highlights: • Novel hCAR activators were identified by computational and biological approaches. • The role

  20. The Size of Activating and Inhibitory Killer Ig-like Receptor Nanoclusters Is Controlled by the Transmembrane Sequence and Affects Signaling

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    Anna Oszmiana

    2016-05-01

    Full Text Available Super-resolution microscopy has revealed that immune cell receptors are organized in nanoscale clusters at cell surfaces and immune synapses. However, mechanisms and functions for this nanoscale organization remain unclear. Here, we used super-resolution microscopy to compare the surface organization of paired killer Ig-like receptors (KIR, KIR2DL1 and KIR2DS1, on human primary natural killer cells and cell lines. Activating KIR2DS1 assembled in clusters two-fold larger than its inhibitory counterpart KIR2DL1. Site-directed mutagenesis established that the size of nanoclusters is controlled by transmembrane amino acid 233, a lysine in KIR2DS1. Super-resolution microscopy also revealed two ways in which the nanoscale clustering of KIR affects signaling. First, KIR2DS1 and DAP12 nanoclusters are juxtaposed in the resting cell state but coalesce upon receptor ligation. Second, quantitative super-resolution microscopy revealed that phosphorylation of the kinase ZAP-70 or phosphatase SHP-1 is favored in larger KIR nanoclusters. Thus, the size of KIR nanoclusters depends on the transmembrane sequence and affects downstream signaling.

  1. Local activation of uterine Toll-like receptor 2 and 2/6 decreases embryo implantation and affects uterine receptivity in mice.

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    Sanchez-Lopez, Javier Arturo; Caballero, Ignacio; Montazeri, Mehrnaz; Maslehat, Nasim; Elliott, Sarah; Fernandez-Gonzalez, Raul; Calle, Alexandra; Gutierrez-Adan, Alfonso; Fazeli, Alireza

    2014-04-01

    Embryo implantation is a complex interaction between maternal endometrium and embryonic structures. Failure to implant is highly recurrent and impossible to diagnose. Inflammation and infections in the female reproductive tract are common causes of infertility, embryo loss, and preterm labor. The current work describes how the activation of endometrial Toll-like receptor (TLR) 2 and 2/6 reduces embryo implantation chances. We developed a morphometric index to evaluate the effects of the TLR 2/6 activation along the uterine horn (UH). TLR 2/6 ligation reduced the endometrial myometrial and glandular indexes and increased the luminal index. Furthermore, TLR 2/6 activation increased the proinflammatory cytokines such as interleukin (IL)-1beta and monocyte chemotactic protein (MCP)-1 in UH lavages in the preimplantation day and IL-1 receptor antagonist in the implantation day. The engagement of TLR 2/6 with its ligand in the UH during embryo transfer severely affected the rate of embryonic implantation (45.00% ± 6.49% vs. 16.69% ± 5.01%, P embryo implantation process was verified using an in vitro model of human embryo implantation where trophoblast spheroids failed to adhere to a monolayer of TLR 2- and TLR 2/6-activated endometrial cells. The inhibition of TLR receptors 2 and 6 in the presence of their specific ligands restored the ability of the spheroids to bind to the endometrial cells. In conclusion, the activation of the innate immune system in the uterus at the time of implantation interfered with the endometrial receptivity and reduced the chances of implantation success.

  2. Duration of treatment and activation of α1-containing GABAA receptors variably affect the level of anxiety and seizure susceptibility after diazepam withdrawal in rats.

    Science.gov (United States)

    Kovačević, Jovana; Timić, Tamara; Tiruveedhula, Veera V; Batinić, Bojan; Namjoshi, Ojas A; Milić, Marija; Joksimović, Srđan; Cook, James M; Savić, Miroslav M

    2014-05-01

    Long-term use of benzodiazepine-type drugs may lead to physical dependence, manifested by withdrawal syndrome after abrupt cessation of treatment. The aim of the present study was to investigate the influence of duration of treatment, as well as the role of α1-containing GABAA receptors, in development of physical dependence to diazepam, assessed through the level of anxiety and susceptibility to pentylenetetrazole (PTZ)-induced seizures, 24h after withdrawal from protracted treatment in rats. Withdrawal of 2mg/kg diazepam after 28, but not after 14 or 21 days of administration led to an anxiety-like behavior in the elevated plus maze. Antagonism of the diazepam effects at α1-containing GABAA receptors, achieved by daily administration of the neutral modulator βCCt (5mg/kg), did not affect the anxiety level during withdrawal. An increased susceptibility to PTZ-induced seizures was observed during diazepam withdrawal after 21 and 28 days of treatment. Daily co-administration of βCCt further decreased the PTZ-seizure threshold after 21 days of treatment, whilst it prevented the diazepam withdrawal-elicited decrease of the PTZ threshold after 28 days of treatment. In conclusion, the current study suggests that the role of α1-containing GABAA receptors in mediating the development of physical dependence may vary based on the effect being studied and duration of protracted treatment. Moreover, the present data supports previous findings that the lack of activity at α1-containing GABAA receptors is not sufficient to eliminate physical dependence liability of ligands of the benzodiazepine type.

  3. TISSUE INHIBITOR OF METALLOPROTEINASE 1, MATRIX METALLOPROTEINASE 9, ALPHA-1 ANTITRYPSIN, METALLOTHIONEIN AND UROKINASE TYPE PLASMINOGEN ACTIVATOR RECEPTOR IN SKIN BIOPSIES FROM PATIENTS AFFECTED BY AUTOIMMUNE BLISTERING DISEASES

    Directory of Open Access Journals (Sweden)

    Ana Maria Abreu Velez

    2013-07-01

    Full Text Available Introduction: Proteinases and proteinase inhibitors have been described to play a role in autoimmune skin blistering diseases. We studied skin lesional biopsies from patients affected by several autoimmune skin blistering diseases for proteinases and proteinase inhibitors. Methods: We utilized immunohistochemistry to evaluate biopsies for alpha-1-antitrypsin, human matrix metalloproteinase 9 (MMP9, human tissue inhibitor of metalloproteinases 1 (TIMP-1, metallothionein and urokinase type plasminogen activator receptor (uPAR. We tested 30 patients affected by endemic pemphigus, 30 controls from the endemic area, and 15 normal controls. We also tested 30 biopsies from patients with bullous pemphigoid (BP, 20 with pemphigus vulgaris (PV, 8 with pemphigus foliaceus, and 14 with dermatitis herpetiformis (DH. Results: Contrary to findings in the current literature, most autoimmune skin blistering disease biopsies were negative for uPAR and MMP9. Only some chronic patients with El Bagre-EPF were positive to MMP9 in the dermis, in proximity to telocytes. TIMP-1 and metallothionein were positive in half of the biopsies from BP patients at the basement membrane of the skin, within several skin appendices, in areas of dermal blood vessel inflammation and within dermal mesenchymal-epithelial cell junctions.

  4. CB1 receptors modulate affective behaviour induced by neuropathic pain.

    Science.gov (United States)

    Rácz, Ildikó; Nent, Elisa; Erxlebe, Edda; Zimmer, Andreas

    2015-05-01

    Patients suffering from chronic pain are often diagnosed with a psychiatric condition, in particular generalized anxiety and major depression. The underlying pathomechanisms contributing to this comorbidity, however, are not entirely clear. In this manuscript we have focussed on the potential role of the cannabinoid receptor CB1, because it is known to modulate neuronal circuits contributing to chronic pain states and affective behaviours. For this purpose we analysed the consequences of a partial sciatic nerve ligation on anxiety- and depression-related behaviours in mice lacking CB1 receptors. Our results show that the development of mechanical hypersensitivity was similar in CB1 deficient mice and wild type controls. However, CB1 knockouts showed much more pronounced behavioural manifestations of anxiety-related behaviours in the light-dark and zero-maze tests, sucrose anhedonia, and disturbed home-cage activity. These results indicate that the endocannabinoid system affects chronic pain-induced mood changes through CB1 receptors.

  5. Peroxisome proliferator-activated receptor {alpha} agonism prevents renal damage and the oxidative stress and inflammatory processes affecting the brains of stroke-prone rats.

    Science.gov (United States)

    Gelosa, Paolo; Banfi, Cristina; Gianella, Anita; Brioschi, Maura; Pignieri, Alice; Nobili, Elena; Castiglioni, Laura; Cimino, Mauro; Tremoli, Elena; Sironi, Luigi

    2010-11-01

    A growing body of evidence suggests that chronic kidney disease is a significant risk for cardiovascular events and stroke regardless of traditional risk factors. The aim of this study was to examine the effects of peroxisome proliferator-activated receptor (PPAR) agonists on the tissue damage affecting salt-loaded spontaneously hypertensive stroke-prone rats ( SHRSPs), an animal model that develops a complex pathology characterized by systemic inflammation, hypertension, and proteinuria and leads to end-organ injury (initially renal and subsequently cerebral). Compared with the PPARγ agonist rosiglitazone, the PPARα ligands fenofibrate and clofibrate significantly increased survival (p damage, and glomerular sclerosis, reduced the number of ED-1-positive cells and collagen accumulation, and decreased the renal expression of interleukin-1β, transforming growth factor β, and monocyte chemoattractant protein 1. It also prevented the plasma and urine accumulation of acute-phase and oxidized proteins, suggesting that the protection induced by PPARα agonists was at least partially caused by their anti-inflammatory and antioxidative properties. The results of this study demonstrate that PPAR agonism has beneficial effects on spontaneous brain and renal damage in SHRSPs by inhibiting systemic inflammation and oxidative stress, and they support carrying out future studies aimed at evaluating the effect of PPARα agonists on proteinuria and clinical outcomes in hypertensive patients with renal disease at increased risk of stroke.

  6. Bisphenol A affects androgen receptor function via multiple mechanisms.

    Science.gov (United States)

    Teng, Christina; Goodwin, Bonnie; Shockley, Keith; Xia, Menghang; Huang, Ruili; Norris, John; Merrick, B Alex; Jetten, Anton M; Austin, Christopher P; Tice, Raymond R

    2013-05-25

    Bisphenol A (BPA), is a well-known endocrine disruptor compound (EDC) that affects the normal development and function of the female and male reproductive system, however the mechanisms of action remain unclear. To investigate the molecular mechanisms of how BPA may affect ten different nuclear receptors, stable cell lines containing individual nuclear receptor ligand binding domain (LBD)-linked to the β-Gal reporter were examined by a quantitative high throughput screening (qHTS) format in the Tox21 Screening Program of the NIH. The results showed that two receptors, estrogen receptor alpha (ERα) and androgen receptor (AR), are affected by BPA in opposite direction. To confirm the observed effects of BPA on ERα and AR, we performed transient transfection experiments with full-length receptors and their corresponding response elements linked to luciferase reporters. We also included in this study two BPA analogs, bisphenol AF (BPAF) and bisphenol S (BPS). As seen in African green monkey kidney CV1 cells, the present study confirmed that BPA and BPAF act as ERα agonists (half maximal effective concentration EC50 of 10-100 nM) and as AR antagonists (half maximal inhibitory concentration IC50 of 1-2 μM). Both BPA and BPAF antagonized AR function via competitive inhibition of the action of synthetic androgen R1881. BPS with lower estrogenic activity (EC50 of 2.2 μM), did not compete with R1881 for AR binding, when tested at 30 μM. Finally, the effects of BPA were also evaluated in a nuclear translocation assays using EGPF-tagged receptors. Similar to 17β-estradiol (E2) which was used as control, BPA was able to enhance ERα nuclear foci formation but at a 100-fold higher concentration. Although BPA was able to bind AR, the nuclear translocation was reduced. Furthermore, BPA was unable to induce functional foci in the nuclei and is consistent with the transient transfection study that BPA is unable to activate AR.

  7. Alendronate affects osteoprotegerin/receptor of activator of nuclear factor κB-ligand expression in human marrow stroma cells in vitro

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To evaluate the effect of alendronate on osteoprotegerin(OPG)and receptor of activator of nuclear factor κB-ligand(RANKL)expression in human marrow stroma cells(hMSCs)in vitro.Methods hMSCs were isolated from human marrow,cultured in vitro,and randomly divided into two groups:alendronate group,hMSCs culture fluid containing 1×10-7mol/L alendronate;control group,no special treatment but culturing hMSCs in DMEM.Two weeks after treatment,the expressions of OPG and RANKL were evaluated by RT-PCR and W...

  8. Genetic and pharmacological evidence that 5-HT2C receptor activation, but not inhibition, affects motivation to feed under a progressive ratio schedule of reinforcement.

    Science.gov (United States)

    Fletcher, Paul J; Sinyard, Judy; Higgins, Guy A

    2010-11-01

    Previous work showed that 5-HT(2C) receptor agonists reduce cocaine self-administration on a progressive ratio (PR) schedule of reinforcement, whereas a 5-HT(2C) receptor antagonist enhances responding for cocaine. The present experiments examined the effects of Ro60-0175 (5-HT(2C) agonist) and SB242084 (5-HT(2C) receptor antagonist) in rats on responding for food on a PR schedule; responding was also determined in mice lacking functional 5-HT(2C) receptors. In food-restricted rats, lever pressing reinforced by regular food pellets or sucrose pellets was reduced by Ro60-0175. This effect was blocked by SB242084, and was absent in mice lacking functional 5-HT(2C) receptors. A number of studies examined the effects of SB242084 on responding for food under a variety of conditions. These included manipulation of food type (regular pellets versus sucrose pellets), nutritional status of the animals (food restriction versus no restriction), and rate of progression of the increase in ratio requirements on the PR schedule. In all cases there was no evidence of enhanced responding for food by SB242084. Mice lacking functional 5-HT(2C) receptors did not differ from wildtype mice in responding for food in either food-restricted or non-restricted states. The effects of Ro60-0175 are consistent with its effects on food consumption and motivation to self-administer cocaine. Unlike their effects on cocaine self-administration, pharmacological blockade of 5-HT(2C) receptors, and genetic disruption of 5-HT(2C) receptor function do not alter the motivation to respond for food. Because the 5-HT(2C) receptor exerts a modulatory effect on dopamine function, the differential effects of reduced 5-HT(2C) receptor mediated transmission on responding for food versus cocaine may relate to a differential role of this neurotransmitter in mediating these two behaviours.

  9. Hydroxyproline-induced Helical Disruption in Conantokin Rl-B Affects Subunit-selective Antagonistic Activities toward Ion Channels of N-Methyl-d-aspartate Receptors.

    Science.gov (United States)

    Kunda, Shailaja; Yuan, Yue; Balsara, Rashna D; Zajicek, Jaroslav; Castellino, Francis J

    2015-07-17

    Conantokins are ~20-amino acid peptides present in predatory marine snail venoms that function as allosteric antagonists of ion channels of the N-methyl-d-aspartate receptor (NMDAR). These peptides possess a high percentage of post-/co-translationally modified amino acids, particularly γ-carboxyglutamate (Gla). Appropriately spaced Gla residues allow binding of functional divalent cations, which induces end-to-end α-helices in many conantokins. A smaller number of these peptides additionally contain 4-hydroxyproline (Hyp). Hyp should prevent adoption of the metal ion-induced full α-helix, with unknown functional consequences. To address this disparity, as well as the role of Hyp in conantokins, we have solved the high resolution three-dimensional solution structure of a Gla/Hyp-containing 18-residue conantokin, conRl-B, by high field NMR spectroscopy. We show that Hyp(10) disrupts only a small region of the α-helix of the Mn(2+)·peptide complex, which displays cation-induced α-helices on each terminus of the peptide. The function of conRl-B was examined by measuring its inhibition of NMDA/Gly-mediated current through NMDAR ion channels in mouse cortical neurons. The conRl-B displays high inhibitory selectivity for subclasses of NMDARs that contain the functionally important GluN2B subunit. Replacement of Hyp(10) with N(8)Q results in a Mg(2+)-complexed end-to-end α-helix, accompanied by attenuation of NMDAR inhibitory activity. However, replacement of Hyp(10) with Pro(10) allowed the resulting peptide to retain its inhibitory property but diminished its GluN2B specificity. Thus, these modified amino acids, in specific peptide backbones, play critical roles in their subunit-selective inhibition of NMDAR ion channels, a finding that can be employed to design NMDAR antagonists that function at ion channels of distinct NMDAR subclasses.

  10. The putative cannabinoid receptor GPR55 affects osteoclast function in vitro and bone mass in vivo

    OpenAIRE

    Whyte, Lauren S.; Ryberg, Erik; Sims, Natalie A.; Ridge, Susan A.; Mackie, Ken; Greasley, Peter J.; Ross, Ruth A.; Rogers, Michael J

    2009-01-01

    GPR55 is a G protein-coupled receptor recently shown to be activated by certain cannabinoids and by lysophosphatidylinositol (LPI). However, the physiological role of GPR55 remains unknown. Given the recent finding that the cannabinoid receptors CB1 and CB2 affect bone metabolism, we examined the role of GPR55 in bone biology. GPR55 was expressed in human and mouse osteoclasts and osteoblasts; expression was higher in human osteoclasts than in macrophage progenitors. Although the GPR55 agonis...

  11. Chapter 8. Activation mechanisms of chemokine receptors

    DEFF Research Database (Denmark)

    Jensen, Pia C; Rosenkilde, Mette M

    2009-01-01

    Chemokine receptors belong to the large family of 7-transmembrane (7TM) G-protein-coupled receptors. These receptors are targeted and activated by a variety of different ligands, indicating that activation is a result of similar molecular mechanisms but not necessarily similar modes of ligand bin...

  12. Mechanism for the activation of glutamate receptors

    Science.gov (United States)

    Scientists at the NIH have used a technique called cryo-electron microscopy to determine a molecular mechanism for the activation and desensitization of ionotropic glutamate receptors, a prominent class of neurotransmitter receptors in the brain and spina

  13. Receptor clustering affects signal transduction at the membrane level in the reaction-limited regime

    Science.gov (United States)

    Caré, Bertrand R.; Soula, Hédi A.

    2013-01-01

    Many types of membrane receptors are found to be organized as clusters on the cell surface. We investigate the potential effect of such receptor clustering on the intracellular signal transduction stage. We consider a canonical pathway with a membrane receptor (R) activating a membrane-bound intracellular relay protein (G). We use Monte Carlo simulations to recreate biochemical reactions using different receptor spatial distributions and explore the dynamics of the signal transduction. Results show that activation of G by R is severely impaired by R clustering, leading to an apparent blunted biological effect compared to control. Paradoxically, this clustering decreases the half maximal effective dose (ED50) of the transduction stage, increasing the apparent affinity. We study an example of inter-receptor interaction in order to account for possible compensatory effects of clustering and observe the parameter range in which such interactions slightly counterbalance the loss of activation of G. The membrane receptors’ spatial distribution affects the internal stages of signal amplification, suggesting a functional role for membrane domains and receptor clustering independently of proximity-induced receptor-receptor interactions.

  14. Triclosan activates aryl hydrocarbon receptor (AhR)-dependent apoptosis and affects Cyp1a1 and Cyp1b1 expression in mouse neocortical neurons.

    Science.gov (United States)

    Szychowski, Konrad A; Wnuk, Agnieszka; Kajta, Małgorzata; Wójtowicz, Anna K

    2016-11-01

    Triclosan (TCS) is an antimicrobial agent that is used extensively in personal care and in sanitizing products, such as soaps, toothpastes, and hair products. A number of studies have revealed the presence of TCS in human tissues, such as fat, liver and brain, in addition to blood and breast milk. The aim of the present study was to investigate the impact of TCS on AhR and Cyp1a1/Cyp1b1 signaling in mouse neocortical neurons in primary cultures. In addition to the use of selective ligands and siRNAs, expression levels of mRNA and proteins as well as caspase-3 activity, reactive oxygen species (ROS) formation, and lactate dehydrogenase (LDH) release have been measured. We also studied the involvement of the AhR in TCS-induced LDH release and caspase-3 activation as well as the effect of TCS on ROS generation. Cultures of neocortical neurons were prepared from Swiss mouse embryos on day 15/16 of gestation. The cells were cultured in phenol red-free Neurobasal medium with B27 and glutamine, and the neurons were exposed to 1 and 10µM TCS. Our experiments showed that the expression of AhR and Cyp1a1 mRNA decreased in cells exposed to 10µM TCS for 3 or 6h. In the case of Cyp1b1, mRNA expression remained unchanged compared with the control group following 3h of exposure to TCS, but after 6h, the mRNA expression of Cyp1b1 was decreased. Our results confirmed that the AhR is involved in the TCS mechanism of action, and our data demonstrated that after the cells were transfected with AhR siRNA, the cytotoxic and pro-apoptotic properties of TCS were decreased. The decrease in Cyp1a1 mRNA and protein expression levels accompanied by a decrease in its activity. The stimulation of Cyp1a1 activity produced by the application of an AhR agonist (βNF) was attenuated by TCS, whereas the addition of AhR antagonist (αNF) reversed the inhibitory effects of TCS. In our experiments, TCS diminished Cyp1b1 mRNA and enhanced its protein expression. In case of Cyp1a1 we observed

  15. Microinfusion of the non-competitive N-methyl-D-aspartate receptor antagonist MK-801 (dizocilpine) into the dorsal hippocampus of wistar rats does not affect latent inhibition and prepulse inhibition, but increases startle reaction and locomotor activity.

    Science.gov (United States)

    Zhang, W N; Bast, T; Feldon, J

    2000-01-01

    Latent inhibition (the retarded conditioning to a stimulus following its repeated non-reinforced pre-exposure) and prepulse inhibition (the reduction in the startle response to an intense acoustic stimulus when this stimulus is immediately preceded by a prepulse) reflect cognitive and sensorimotor gating processes, respectively, and are deficient in schizophrenic patients. The disruption of latent inhibition and prepulse inhibition in the rat is used as an animal model for the attentional deficits associated with schizophrenia. The present study tested the extent to which latent inhibition and prepulse inhibition, startle reaction and locomotor activity in the open field were affected by infusing the non-competitive N-methyl-D-aspartate receptor antagonist MK-801 (dizocilpine) into the dorsal hippocampus of Wistar rats. We used the same dose of MK-801 (6.25microg/0.5microl per side) previously found to be effective in the disruption of prepulse inhibition when infused into the dorsal hippocampus of Sprague-Dawley rats [Bakshi V. P. and Geyer M. A. (1998) J. Neurosci. 18, 8394-8401; Bakshi V. P. and Geyer M. A. (1999) Neuroscience 92, 113-121]. Bilateral infusion of MK-801 into the dorsal hippocampus did not disrupt latent inhibition. Furthermore, in contrast to previous studies, we failed to find a significant disruption of prepulse inhibition after MK-801 infusion into the dorsal hippocampus, although MK-801 infusion was effective in increasing the startle amplitude as well as locomotor activity in an open field. From our results, we suggest that N-methyl-D-aspartate receptor-mediated processes within the dorsal hippocampus are not necessary for the normal maintenance of the attentional processes reflected by latent inhibition and prepulse inhibition.

  16. Activation of glycine site and GluN2B subunit of NMDA receptors is necessary for ERK/CREB signaling cascade in rostral anterior cingulate cortex in rats: Implications for affective pain

    Institute of Scientific and Technical Information of China (English)

    Hong Cao; Wen-Hua Ren; Mu-Ye Zhu; Zhi-Qi Zhao; Yu-Qiu Zhang

    2012-01-01

    Objective The rostral anterior cingulate cortex (rACC) is implicated in processing the emotional component of pain.N-methyl-D-aspartate receptors (NMDARs) are highly expressed in the rACC and mediate painrelated affect by activating a signaling pathway that involves cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and/or extracellular regulated kinase (ERK)/cAMP-response element-binding protein (CREB).The present study investigated the contributions of the NMDAR glycine site and GluN2B subunit to the activation of ERK and CREB both in vitro and in vivo in rat rACC.Methods Immunohistochemistry and Western blot analysis were used to separately assess the expression of phospho-ERK (pERK) and phospho-CREB (pCREB) in vitro and in vivo.Double immunostaining was also used to determine the colocalization of pERK and pCREB.Results Both bath application of NMDA in brain slices in vitro and intraplantar injection of formalin into the rat hindpaw in vivo induced significant up-regulation of pERK and pCREB in the rACC,which was inhibited by the NMDAR antagonist DL-2-amino-5-phospho-novaleric acid.Selective blockade of the NMDAR GluN2B subunit and the glycinebinding site,or degradation of endogenous D-serine,a co-agonist for the glycine site,significantly decreased the upregulation of pERK and pCREB expression in the rACC.Further,the activated ERK predominantly colocalized with CREB.Conclusion Either the glycine site or the GluN2B subunit of NMDARs participates in the phosphorylation of ERK and CREB induced by bath application of NMDA in brain slices or hindpaw injection of 5% formalin in rats,and these might be fundamental molecular mechanisms underlying pain affect.

  17. CERAPP: Collaborative Estrogen Receptor Activity Prediction Project

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) demonstrating using predictive computational...

  18. 2,3,7,8-Tetrachlorodibenzo-p-dioxin activates the aryl hydrocarbon receptor and alters sex steroid hormone secretion without affecting growth of mouse antral follicles in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Karman, Bethany N., E-mail: bklement@illinois.edu; Basavarajappa, Mallikarjuna S., E-mail: mbshivapur@gmail.com; Craig, Zelieann R., E-mail: zelieann@illinois.edu; Flaws, Jodi A., E-mail: jflaws@illinois.edu

    2012-05-15

    The persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an ovarian toxicant. These studies were designed to characterize the actions of TCDD on steroidogenesis and growth of intact mouse antral follicles in vitro. Specifically, these studies tested the hypothesis that TCDD exposure leads to decreased sex hormone production/secretion by antral follicles as well as decreased growth of antral follicles in vitro. Since TCDD acts through binding to the aryl hydrocarbon receptor (AHR), and the AHR has been identified as an important factor in ovarian function, we also conducted experiments to confirm the presence and activation of the AHR in our tissue culture system. To do so, we exposed mouse antral follicles for 96 h to a series of TCDD doses previously shown to have effects on ovarian tissues and cells in culture, which also encompass environmentally relevant and pharmacological exposures (0.1–100 nM), to determine a dose response for TCDD in our culture system for growth, hormone production, and expression of the Ahr and Cyp1b1. The results indicate that TCDD decreases progesterone, androstenedione, testosterone, and estradiol levels in a non-monotonic dose response manner without altering growth of antral follicles. The addition of pregnenolone substrate (10 μM) restores hormone levels to control levels. Additionally, Cyp1b1 levels were increased by 3–4 fold regardless of the dose of TCDD exposure, evidence of AHR activation. Overall, these data indicate that TCDD may act prior to pregnenolone formation and through AHR transcriptional control of Cyp1b1, leading to decreased hormone levels without affecting growth of antral follicles. -- Highlights: ►TCDD disrupts sex steroid hormone levels, but not growth of antral follicles. ►Pregnenolone co-treatment by-passes TCDD-induced steroid hormone disruption. ►TCDD affects steroid hormone levels through an AHR pathway in antral follicles.

  19. PSD-95 regulates D1 dopamine receptor resensitization, but not receptor-mediated Gs-protein activation

    Institute of Scientific and Technical Information of China (English)

    Peihua Sun; Jingru Wang; Weihua Gu; Wei Cheng; Guo-zhang Jin; Eitan Friedman; Jie Zheng; Xuechu Zhen

    2009-01-01

    The present study aims to define the role of postsynaptic density (PSD)-95 in the regulation of dopamine (DA) receptor function. We found that PSD-95 physically associates with either D1 or D2 DA receptors in co-transfected HEK-293 cells. Stimulation of DA receptors altered the association between D1 receptor and PSD-95 in a time-depen-dent manner. Functional assays indicated that PSD-95 co-expression did not affect D1 receptor-stimulated cAMP pro-duction, Gs-protein activation or receptor desensitization. However, PSD-95 accelerated the recovery of internalized membrane receptors by promoting receptor recycling, thus resulting in enhanced resensitization of internalized D1 receptors. Our results provide a novel mechanism for regulating DA receptor recycling that may play an important role in postsynaptic DA functional modulation and synaptic neuroplasticity.

  20. Peroxisome Proliferator-activated Receptor-γ2 Pro12Ala and C-689T Polymorphisms and Haplotypes Affect the Profiles of Coronary Heart Disease in Diabetic Chinese People

    Institute of Scientific and Technical Information of China (English)

    Jianping Li; Longxian Cheng; Meian He; Tangchun Wu

    2008-01-01

    Objectives Peroxisome proliferator-activated receptor-γ2 (PPARγ2) variant Pro12Ala was demonstrated with risk of coronary heart disease(CHD)and type 2 diabetes mellitus(T2DM).Another variant C-689T in the promoter was reported with lower receptor activity but lack of reports on association between C-689T and CHD or T2DM.Methods A total of 351 subjects without CHD and T2DM(controls)and 125 patients with CHD and T2DM(cases)were enrolled in our case-control study.Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) was used to detect Pro12Ala and C-689T polymorphisms.And effects on CHD merged with T2DM of the two polymorphisms were analyzed in individual and haplotype analyses.Results In the study,Pro12Pro,Pro12Ala and Ala12Ala genotype frequencies were 92.9%,6.8%and0.3% in controls;92.8%,7.2% and 0.0% in cases respectively whilst CC,CT and TT genotype frequencies were 93.4%,6.3% and 0.3% in controls;92.8%,7.2%and0.0% in cases respectively.Pro12Ala and C-689T polymorphisms were in strong linkage disequilibrium (D'=0.81,P=0.000)and the observed haplotype frequency of Pro-C,Pro-T,Ala-C and Ala-T was 0.957,0.006,0.008and0.028 respectively.No significant associations were detected between the two polymorphisms and CHD merged with T2DM in either individual or haplotype analyses.In subjects with obesity[body mass index (BMI)≥ 25 kg/m2],we found that both Pro12Ala and C-689T polymorphisms were associated with BMI.In haplotype analyses,we found that Pro12Ala and C-689 T haplotypes had associations with systolic blood pressure in total population,with BMI,waist circle and total holesterol(TC)in obesity subgroup and with fasting blood glucose and TC in males.Conclusions PPARγ2Pro12Ala and C-689T polymorphisms and haplotypes affect the profiles of CHD merged with T2DM in Chinese Han people.

  1. Calmodulin affects sensitization of Drosophila melanogaster odorant receptors

    Directory of Open Access Journals (Sweden)

    Latha eMukunda

    2016-02-01

    Full Text Available Flying insects have developed a remarkably sensitive olfactory system to detect faint and turbulent odor traces. This ability is linked to the olfactory receptors class of odorant receptors (ORs, occurring exclusively in winged insects. ORs form heteromeric complexes of an odorant specific receptor protein (OrX and a highly conserved co-receptor protein (Orco. The ORs form ligand gated ion channels that are tuned by intracellular signaling systems. Repetitive subthreshold odor stimulation of olfactory sensory neurons sensitizes insect ORs. This OR sensitization process requires Orco activity. In the present study we first asked whether OR sensitization can be monitored with heterologously expressed OR proteins. Using electrophysiological and calcium imaging methods we demonstrate that D. melanogaster OR proteins expressed in CHO cells show sensitization upon repeated weak stimulation. This was found for OR channels formed by Orco as well as by Or22a or Or56a and Orco. Moreover, we show that inhibition of calmodulin (CaM action on OR proteins, expressed in CHO cells, abolishes any sensitization. Finally, we investigated the sensitization phenomenon using an ex vivo preparation of olfactory sensory neurons (OSNs expressing Or22a inside the fly’s antenna. Using calcium imaging, we observed sensitization in the dendrites as well as in the soma. Inhibition of calmodulin with W7 disrupted the sensitization within the outer dendritic shaft, whereas the sensitization remained in the other OSN compartments. Taken together, our results suggest that CaM action is involved in sensitizing the OR complex and that this mechanisms accounts for the sensitization in the outer dendrites, whereas further mechanisms contribute to the sensitization observed in the other OSN compartments. The use of heterologously expressed OR proteins appears to be suitable for further investigations on the mechanistic basis of OR sensitization, while investigations on native

  2. Activities of nicotinic acetylcholine receptors modulate neurotransmission and synaptic architecture

    Institute of Scientific and Technical Information of China (English)

    Akira Oda; Hidekazu Tanaka

    2014-01-01

    The cholinergic system is involved in a broad spectrum of brain function, and its failure has been implicated in Alzheimer’s disease. Acetylcholine transduces signals through muscarinic and nicotinic acetylcholine receptors, both of which inlfuence synaptic plasticity and cognition. However, the mechanisms that relate the rapid gating of nicotinic acetylcholine receptors to per-sistent changes in brain function have remained elusive. Recent evidence indicates that nicotinic acetylcholine receptors activities affect synaptic morphology and density, which result in per-sistent rearrangements of neural connectivity. Further investigations of the relationships between nicotinic acetylcholine receptors and rearrangements of neural circuitry in the central nervous system may help understand the pathogenesis of Alzheimer’s disease.

  3. Active Affective Learning for Accelerated Schools.

    Science.gov (United States)

    Richardson, Robert B.

    This paper provides the groundwork for Active Affective Learning and teaching adapted to the needs of the disadvantaged, at-risk students served by the Accelerated Schools Movement. One of the "golden rules" for the practice of Accelerated Learning, according to psychiatrist Georgi Lozanov, has been to maintain an "up-beat" classroom presentation…

  4. Peroxisome Proliferator-Activated Receptor and Vitamin D Receptor Signaling Pathways in Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Satoru, E-mail: smatsuda@cc.nara-wu.ac.jp; Kitagishi, Yasuko [Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506 (Japan)

    2013-10-21

    Peroxisome proliferator-activated receptors (PPARs) are members of the superfamily of nuclear hormone receptors, which respond to specific ligands such as polyunsaturated fatty acids by altering gene expression. Three subtypes of this receptor have been discovered, each evolving to achieve different biological functions. Like other nuclear receptors, the transcriptional activity of PPARs is affected not only by ligand-stimulation, but also by cross-talk with other molecules. For example, both PPARs and the RXRs are ligand-activated transcription factors that coordinately regulate gene expression. In addition, PPARs and vitamin D receptor (VDR) signaling pathways regulate a multitude of genes that are of importance for cellular functions including cell proliferation and cell differentiation. Interaction of the PPARs and VDR signaling pathways has been shown at the level of molecular cross-regulation of their transcription factor. A variety of ligands influencing the PPARs and VDR signaling pathways have been shown to reveal chemopreventive potential by mediating tumor suppressive activities in human cancers. Use of these compounds may represent a potential novel strategy to prevent cancers. This review summarizes the roles of the PPARs and the VDR in pathogenesis and progression of cancer.

  5. NMDA receptor activity in neuropsychiatric disorders

    Directory of Open Access Journals (Sweden)

    Shaheen E Lakhan

    2013-06-01

    Full Text Available N-Methyl-D-aspartate (NMDA receptors play a variety of physiologic roles and their proper signaling is essential for cellular homeostasis. Any disruption in this pathway, leading to either enhanced or decreased activity, may result in the manifestation of neuropsychiatric pathologies such as schizophrenia, mood disorders, substance induced psychosis, Huntington's disease, Alzheimer's disease, and neuropsychiatric systemic lupus erythematosus. Here, we explore the notion that the overlap in activity of at least one biochemical pathway, the NMDA receptor pathway, may be the link to understanding the overlap in psychotic symptoms between diseases. This review intends to present a broad overview of those neuropsychiatric disorders for which alternations in NMDA receptor activity is prominent thus suggesting that continued direction of pharmaceutical intervention to this pathway may present a viable option for managing symptoms.

  6. Mechanism of FGF receptor dimerization and activation

    Science.gov (United States)

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise.

  7. Allosteric modulators affect the internalization of human adenosine A1 receptors.

    NARCIS (Netherlands)

    Klaasse, E.C.; Hout, G. van den; Roerink, S.F.; Grip, W.J. de; IJzerman, A.P.; Beukers, M.W.

    2005-01-01

    To study the effect of allosteric modulators on the internalization of human adenosine A(1) receptors, the receptor was equipped with a C-terminal yellow fluorescent protein tag. The introduction of this tag did not affect the radioligand binding properties of the receptor. CHO cells stably expressi

  8. Activation of Neuropeptide FF Receptors by Kisspeptin Receptor Ligands.

    Science.gov (United States)

    Oishi, Shinya; Misu, Ryosuke; Tomita, Kenji; Setsuda, Shohei; Masuda, Ryo; Ohno, Hiroaki; Naniwa, Yousuke; Ieda, Nahoko; Inoue, Naoko; Ohkura, Satoshi; Uenoyama, Yoshihisa; Tsukamura, Hiroko; Maeda, Kei-Ichiro; Hirasawa, Akira; Tsujimoto, Gozoh; Fujii, Nobutaka

    2011-01-13

    Kisspeptin is a member of the RFamide neuropeptide family that is implicated in gonadotropin secretion. Because kisspeptin-GPR54 signaling is implicated in the neuroendocrine regulation of reproduction, GPR54 ligands represent promising therapeutic agents against endocrine secretion disorders. In the present study, the selectivity profiles of GPR54 agonist peptides were investigated for several GPCRs, including RFamide receptors. Kisspeptin-10 exhibited potent binding and activation of neuropeptide FF receptors (NPFFR1 and NPFFR2). In contrast, short peptide agonists bound with much lower affinity to NPFFRs while showing relatively high selectivity toward GPR54. The possible localization of secondary kisspeptin targets was also demonstrated by variation in the levels of GnRH release from the median eminence and the type of GPR54 agonists used. Negligible affinity of the reported NPFFR ligands to GPR54 was observed and indicates the unidirectional cross-reactivity between both ligands.

  9. Do recreational activities affect coastal biodiversity?

    Science.gov (United States)

    Riera, Rodrigo; Menci, Cristiano; Sanabria-Fernández, José Antonio; Becerro, Mikel A.

    2016-09-01

    Human activities are largely affecting coastal communities worldwide. Recreational perturbations have been overlooked in comparison to other perturbations, yet they are potential threats to marine biodiversity. They affect coastal communities in different ways, underpinning consistent shifts in fish and invertebrates assemblages. Several sites were sampled subjected to varying effects by recreational fishermen (low and high pressure) and scuba divers (low and high) in an overpopulated Atlantic island. Non-consistent differences in ecological, trophic and functional diversity were found in coastal communities, considering both factors ("diving" and "fishing"). Multivariate analyses only showed significant differences in benthic invertebrates between intensively-dived and non-dived sites. The lack of clear trends may be explained by the depletion of coastal resources in the study area, an extensively-affected island by overfishing.

  10. Repeated stressful experiences differently affect brain dopamine receptor subtypes

    Energy Technology Data Exchange (ETDEWEB)

    Puglisi-Allegra, S.; Cabib, S. (Istituto di Psicobiologia e Psicofarmacologia (CNR), Roma (Italy)); Kempf, E.; Schleef, C. (Centre de Neurochimi, Strasbourg (Italy))

    1991-01-01

    The binding of tritiated spiperone (D2 antagonist) and tritiated SCH 23390 (D1 antagonist), in vivo, was investigated in the caudatus putamen (CP) and nucleus accumbens septi (NAS) of mice submitted to ten daily restraint stress sessions. Mice sacrificed 24 hr after the last stressful experience presented a 64% decrease of D2 receptor density (Bmax) but no changes in D1 receptor density in the NAS. In the CP a much smaller (11%) reduction of D2 receptor density was accompanied by a 10% increase of D1 receptors. These results show that the two types of dopamine (DA) receptors adapt in different or even opposite ways to environmental pressure, leading to imbalance between them.

  11. CERAPP: Collaborative estrogen receptor activity prediction project

    DEFF Research Database (Denmark)

    Mansouri, Kamel; Abdelaziz, Ahmed; Rybacka, Aleksandra

    2016-01-01

    Background: Humans are exposed to thousands of man-made chemicals in the environment. Some chemicals mimic natural endocrine hormones and, thus, have the potential to be endocrine disruptors. Most of these chemicals have never been tested for their ability to interact with the estrogen receptor (ER......). Risk assessors need tools to prioritize chemicals for evaluation in costly in vivo tests, for instance, within the U.S. EPA Endocrine Disruptor Screening Program. oBjectives: We describe a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project...

  12. Sex Steroid Hormone Receptor Expression Affects Ovarian Cancer Survival

    DEFF Research Database (Denmark)

    Jönsson, Jenny-Maria; Skovbjerg Arildsen, Nicolai; Malander, Susanne;

    2015-01-01

    BACKGROUND AND AIMS: Although most ovarian cancers express estrogen (ER), progesterone (PR), and androgen (AR) receptors, they are currently not applied in clinical decision making. We explored the prognostic impact of sex steroid hormone receptor protein and mRNA expression on survival...... in epithelial ovarian cancer. METHODS: Immunohistochemical stainings for ERα, ERβ, PR, and AR were assessed in relation to survival in 118 serous and endometrioid ovarian cancers. Expression of the genes encoding the four receptors was studied in relation to prognosis in the molecular subtypes of ovarian cancer...... in ovarian cancer and support that tumors should be stratified based on molecular as well as histological subtypes in future studies investigating the role of endocrine treatment in ovarian cancer....

  13. Phenobarbital and Insulin Reciprocate Activation of the Nuclear Receptor Constitutive Androstane Receptor through the Insulin Receptor.

    Science.gov (United States)

    Yasujima, Tomoya; Saito, Kosuke; Moore, Rick; Negishi, Masahiko

    2016-05-01

    Phenobarbital (PB) antagonized insulin to inactivate the insulin receptor and attenuated the insulin receptor downstream protein kinase B (AKT)-forkhead box protein O1 and extracellular signal-regulated kinase 1/2 signals in mouse primary hepatocytes and HepG2 cells. Hepatic AKT began dephosphorylation in an early stage of PB treatment, and blood glucose levels transiently increased in both wild-type and constitutive androstane receptor (CAR) knockout (KO) mice. On the other hand, blood glucose levels increased in wild-type mice, but not KO mice, in later stages of PB treatment. As a result, PB, acting as an insulin receptor antagonist, elicited CAR-independent increases and CAR-dependent decreases of blood glucose levels at these different stages of treatment, respectively. Reciprocally, insulin activation of the insulin receptor repressed CAR activation and induction of its target CYP2B6 gene in HepG2 cells. Thus, PB and insulin cross-talk through the insulin receptor to regulate glucose and drug metabolism reciprocally.

  14. Activation of EphA receptors mediates the recruitment of the adaptor protein Slap, contributing to the downregulation of N-methyl-D-aspartate receptors.

    Science.gov (United States)

    Semerdjieva, Sophia; Abdul-Razak, Hayder H; Salim, Sharifah S; Yáñez-Muñoz, Rafael J; Chen, Philip E; Tarabykin, Victor; Alifragis, Pavlos

    2013-04-01

    Regulation of the activity of N-methyl-d-aspartate receptors (NMDARs) at glutamatergic synapses is essential for certain forms of synaptic plasticity underlying learning and memory and is also associated with neurotoxicity and neurodegenerative diseases. In this report, we investigate the role of Src-like adaptor protein (Slap) in NMDA receptor signaling. We present data showing that in dissociated neuronal cultures, activation of ephrin (Eph) receptors by chimeric preclustered eph-Fc ligands leads to recruitment of Slap and NMDA receptors at the sites of Eph receptor activation. Interestingly, our data suggest that prolonged activation of EphA receptors is as efficient in recruiting Slap and NMDA receptors as prolonged activation of EphB receptors. Using established heterologous systems, we examined whether Slap is an integral part of NMDA receptor signaling. Our results showed that Slap does not alter baseline activity of NMDA receptors and does not affect Src-dependent potentiation of NMDA receptor currents in Xenopus oocytes. We also demonstrate that Slap reduces excitotoxic cell death triggered by activation of NMDARs in HEK293 cells. Finally, we present evidence showing reduced levels of NMDA receptors in the presence of Slap occurring in an activity-dependent manner, suggesting that Slap is part of a mechanism that homeostatically modulates the levels of NMDA receptors.

  15. Radioiodination of chicken luteinizing hormone without affecting receptor binding potency

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, M.; Ishii, S. (Waseda Univ., Tokyo (Japan))

    1989-12-01

    By improving the currently used lactoperoxidase method, we were able to obtain radioiodinated chicken luteinizing hormone (LH) that shows high specific binding and low nonspecific binding to a crude plasma membrane fraction of testicular cells of the domestic fowl and the Japanese quail, and to the ovarian granulosa cells of the Japanese quail. The change we made from the original method consisted of (1) using chicken LH for radioiodination that was not only highly purified but also retained a high receptor binding potency; (2) controlling the level of incorporation of radioiodine into chicken LH molecules by employing a short reaction time and low temperature; and (3) fractionating radioiodinated chicken LH further by gel filtration using high-performance liquid chromatography. Specific radioactivity of the final {sup 125}I-labeled chicken LH preparation was 14 microCi/micrograms. When specific binding was 12-16%, nonspecific binding was as low as 2-4% in the gonadal receptors. {sup 125}I-Labeled chicken LH was displaced by chicken LH and ovine LH but not by chicken follicle-stimulating hormone. The equilibrium association constant of quail testicular receptor was 3.6 x 10(9) M-1. We concluded that chicken LH radioiodinated by the present method is useful for studies of avian LH receptors.

  16. Minor modifications to the phosphate groups and the C3' acyl chain length of lipid A in two Bordetella pertussis strains, BP338 and 18-323, independently affect Toll-like receptor 4 protein activation.

    Science.gov (United States)

    Shah, Nita R; Albitar-Nehme, Sami; Kim, Emma; Marr, Nico; Novikov, Alexey; Caroff, Martine; Fernandez, Rachel C

    2013-04-26

    Lipopolysaccharides (LPS) of Bordetella pertussis are important modulators of the immune system. Interaction of the lipid A region of LPS with the Toll-like receptor 4 (TLR4) complex causes dimerization of TLR4 and activation of downstream nuclear factor κB (NFκB), which can lead to inflammation. We have previously shown that two strains of B. pertussis, BP338 (a Tohama I-derivative) and 18-323, display two differences in lipid A structure. 1) BP338 can modify the 1- and 4'-phosphates by the addition of glucosamine (GlcN), whereas 18-323 cannot, and 2) the C3' acyl chain in BP338 is 14 carbons long, but only 10 or 12 carbons long in 18-323. In addition, BP338 lipid A can activate TLR4 to a greater extent than 18-323 lipid A. Here we set out to determine the genetic reasons for the differences in these lipid A structures and the contribution of each structural difference to the ability of lipid A to activate TLR4. We show that three genes of the lipid A GlcN modification (Lgm) locus, lgmA, lgmB, and lgmC (previously locus tags BP0399-BP0397), are required for GlcN modification and a single amino acid difference in LpxA is responsible for the difference in C3' acyl chain length. Furthermore, by introducing lipid A-modifying genes into 18-323 to generate isogenic strains with varying penta-acyl lipid A structures, we determined that both modifications increase TLR4 activation, although the GlcN modification plays a dominant role. These results shed light on how TLR4 may interact with penta-acyl lipid A species.

  17. AMPK Activation Affects Glutamate Metabolism in Astrocytes

    DEFF Research Database (Denmark)

    Voss, Caroline Marie; Pajęcka, Kamilla; Stridh, Malin H

    2015-01-01

    on glutamate metabolism in astrocytes was studied using primary cultures of these cells from mouse cerebral cortex during incubation in media containing 2.5 mM glucose and 100 µM [U-(13)C]glutamate. The metabolism of glutamate including a detailed analysis of its metabolic pathways involving the tricarboxylic...... acid (TCA) cycle was studied using high-performance liquid chromatography analysis supplemented with gas chromatography-mass spectrometry technology. It was found that AMPK activation had profound effects on the pathways involved in glutamate metabolism since the entrance of the glutamate carbon...... affected by a reduction of the flux of glutamate derived carbon through the malic enzyme and pyruvate carboxylase catalyzed reactions. Finally, it was found that in the presence of glutamate as an additional substrate, glucose metabolism monitored by the use of tritiated deoxyglucose was unaffected by AMPK...

  18. Peroxisome proliferator-activated receptors for hypertension

    Institute of Scientific and Technical Information of China (English)

    Daisuke; Usuda; Tsugiyasu; Kanda

    2014-01-01

    Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors belonging to the nuclear receptor superfamily, which is composed of four members encoded by distinct genes(α, β, γ, and δ). The genes undergo transactivation or transrepression under specific mechanisms that lead to the induction or repression of target gene expression. As is the case with other nuclear receptors, all four PPAR isoforms contain five or six structural regions in four functional domains; namely, A/B, C, D, and E/F. PPARs have many functions, particularly functions involving control of vascular tone, inflammation, and energy homeostasis, and are, therefore, important targets for hypertension, obesity, obesity-induced inflammation, and metabolic syndrome in general. Hence, PPARs also represent drug targets, and PPARα and PPARγ agonists are used clinically in the treatment of dyslipidemia and type 2 diabetes mellitus, respectively. Because of their pleiotropic effects, they have been identified as active in a number of diseases and are targets for the development of a broad range of therapies for a variety of diseases. It is likely that the range of PPARγ agonist therapeutic actions will result in novel approaches to lifestyle and other diseases. The combination of PPARs with reagents or with other cardiovascular drugs, such as diuretics and angiotensin Ⅱ receptor blockers, should be studied.This article provides a review of PPAR isoform characteristics, a discussion of progress in our understanding of the biological actions of PPARs, and a summary of PPAR agonist development for patient management. We also include a summary of the experimental and clinical evidence obtained from animal studies and clinical trials conducted to evaluate the usefulness and effectiveness of PPAR agonists in the treatment of lifestyle-related diseases.

  19. Hyaluronic acid induces activation of the κ-opioid receptor.

    Directory of Open Access Journals (Sweden)

    Barbara Zavan

    Full Text Available INTRODUCTION: Nociceptive pain is one of the most common types of pain that originates from an injury involving nociceptors. Approximately 60% of the knee joint innervations are classified as nociceptive. The specific biological mechanism underlying the regulation of nociceptors is relevant for the treatment of symptoms affecting the knee joint. Intra-articular administration of exogenous hyaluronic acid (HA in patients with osteoarthritis (OA appears to be particularly effective in reducing pain and improving patient function. METHODS: We performed an in vitro study conducted in CHO cells that expressed a panel of opioid receptors and in primary rat dorsal root ganglion (DRG neurons to determine if HA induces the activation of opioid peptide receptors (OPr using both aequorin and the fluorescent dye Fura-2/AM. RESULTS: Selective agonists and antagonists for each OPr expressed on CHO cells were used to test the efficacy of our in vitro model followed by stimulation with HA. The results showed that HA induces stimulatory effects on the κ receptor (KOP. These effects of HA were also confirmed in rat DRG neurons, which express endogenously the OPr. CONCLUSIONS: HA activates the KOP receptor in a concentration dependent manner, with a pEC(50 value of 7.57.

  20. Cellular receptors for plasminogen activators recent advances.

    Science.gov (United States)

    Ellis, V

    1997-10-01

    The generation of the broad-specificity protease plasmin by the plasminogen activators urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) is implicated in a variety of pathophysiological processes, including vascular fibrin dissolution, extracellular matrix degradation and remodeling, and cell migration. A mechanism for the regulation of plasmin generation is through binding of the plasminogen activators to specific cellular receptors: uPA to the glycolipid-anchored membrane protein urokinase-type plasminogen activator receptor (uPAR) and tPA to a number of putative binding sites. The uPA-uPAR complex can interact with a variety of ligands, including plasminogen, vitronectin, and integrins, indicating a multifunctional role for uPAR, regulating not only efficient and spatially restricted plasmin generation but also having the potential to modulate cell adhesion and signal transduction. The cellular binding of tPA, although less well characterized, also has the capacity to regulate plasmin generation and to play a significant role in vessel-wall biology. (Trends Cardiovasc Med 1997;7:227-234). © 1997, Elsevier Science Inc.

  1. Dual effect on the RET receptor of MEN 2 mutations affecting specific extracytoplasmic cysteines.

    Science.gov (United States)

    Chappuis-Flament, S; Pasini, A; De Vita, G; Ségouffin-Cariou, C; Fusco, A; Attié, T; Lenoir, G M; Santoro, M; Billaud, M

    1998-12-03

    The RET gene encodes a receptor tyrosine kinase whose function is essential during the development of kidney and the intestinal nervous system. Germline mutations affecting one of five cysteines (Cys609, 611, 618, 620 and 634) located in the juxtamembrane domain of the RET receptor are responsible for the vast majority of two cancer-prone disorders, multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC). These mutations lead to the replacement of a cysteine by an alternate amino acid. Mutations of the RET gene are also the underlying genetic cause of Hirschsprung disease (HSCR), a congenital aganglionosis of the hindgut. In a fraction of kindreds, MEN 2A cosegregate with HSCR and affected individuals carry a single mutation at codons 609, 618 or 620. To examine the consequences of cysteine substitution on RET function, we have introduced a Cys to Arg mutation into the wild-type RET at either codons 609, 618, 620, 630 or 634. We now report that each mutation induces a constitutive catalytic activity due to the aberrant disulfide homodimerization of RET. However, mutations 630 and 634 activate RET more strongly than mutations 609, 618 or 620 as demonstrated by quantitative assays in rodent fibroblasts and pheochromocytoma PC12 cells. Biochemical analysis revealed that mutations 618 and 620, and to a lesser extent mutation 609, result in a marked reduction of the level of RET at the cell surface and as a consequence decrease the amount of RET covalent dimer. These findings provide a molecular basis explaining the range of phenotype engendered by alterations of RET cysteines and suggest a novel mechanism whereby mutations of cysteines 609, 618 and 620 exert both activating and inactivating effects.

  2. Recovery of network-driven glutamatergic activity in rat hippocampal neurons during chronic glutamate receptor blockade.

    Science.gov (United States)

    Leininger, Eric; Belousov, Andrei B

    2009-01-28

    Previous studies indicated that a long-term decrease in the activity of ionotropic glutamate receptors induces cholinergic activity in rat and mouse hypothalamic neuronal cultures. Here we studied whether a prolonged inactivation of ionotropic glutamate receptors also induces cholinergic activity in hippocampal neurons. Receptor activity was chronically suppressed in rat hippocampal primary neuronal cultures with two proportionally increasing sets of concentrations of NMDA plus non-NMDA receptor antagonists: 100 microM/10 microM AP5/CNQX (1X cultures) and 200 microM/20 microM AP5/CNQX (2X cultures). Using calcium imaging we demonstrate that cholinergic activity does not develop in these cultures. Instead, network-driven glutamate-dependent activity, that normally is detected in hyper-excitable conditions, reappears in each culture group in the presence of these antagonists and can be reversibly suppressed by higher concentrations of AP5/CNQX. This activity is mediated by non-NMDA receptors and is modulated by NMDA receptors. Further, non-NMDA receptors, the general level of glutamate receptor activity and CaMK-dependent signaling are critical for development of this network-driven glutamatergic activity in the presence of receptor antagonists. Using electrophysiology, western blotting and calcium imaging we show that some neuronal parameters are either reduced or not affected by chronic glutamate receptor blockade. However, other parameters (including neuronal excitability, mEPSC frequency, and expression of GluR1, NR1 and betaCaMKII) become up-regulated and, in some cases, proportionally between the non-treated, 1X and 2X cultures. Our data suggest recovery of the network-driven glutamatergic activity after chronic glutamate receptor blockade. This recovery may represent a form of neuronal plasticity that compensates for the prolonged suppression of the activity of glutamate receptors.

  3. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen;

    2015-01-01

    densities in mitochondria. Activation of the cell membrane AT2 receptors by a concomitant treatment with angiotensin II and the AT1 receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT2 receptor...... of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT2 receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high...... agonist, Compound 21 (C21) penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT2 receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped from the cell death, displayed activation of the mitochondrial apoptotic pathway, i...

  4. The receptor for advanced glycation end products (RAGE) affects T cell differentiation in OVA induced asthma.

    Science.gov (United States)

    Akirav, Eitan M; Henegariu, Octavian; Preston-Hurlburt, Paula; Schmidt, Ann Marie; Clynes, Raphael; Herold, Kevan C

    2014-01-01

    The receptor for glycation end products (RAGE) has been previously implicated in shaping the adaptive immune response. RAGE is expressed in T cells after activation and constitutively in T cells from patients with diabetes. The effects of RAGE on adaptive immune responses are not clear: Previous reports show that RAGE blockade affects Th1 responses. To clarify the role of RAGE in adaptive immune responses and the mechanisms of its effects, we examined whether RAGE plays a role in T cell activation in a Th2 response involving ovalbumin (OVA)-induced asthma in mice. WT and RAGE deficient wild-type and OT-II mice, expressing a T cell receptor specific for OVA, were immunized intranasally with OVA. Lung cellular infiltration and T cell responses were analyzed by immunostaining, FACS, and multiplex bead analyses for cytokines. RAGE deficient mice showed reduced cellular infiltration in the bronchial alveolar lavage fluid and impaired T cell activation in the mediastinal lymph nodes when compared with WT mice. In addition, RAGE deficiency resulted in reduced OT-II T cell infiltration of the lung and impaired IFNγ and IL-5 production when compared with WT mice and reduced infiltration when transferred into WT hosts. When cultured under conditions favoring the differentiation of T cells subsets, RAGE deficient T cells showed reduced production of IFNγ but increased production of IL-17. Our data show a stimulatory role for RAGE in T activation in OVA-induced asthma. This role is largely mediated by the effects of RAGE on T cell proliferation and differentiation. These findings suggest that RAGE may play a regulatory role in T cell responses following immune activation.

  5. Methylthioadenosine reprograms macrophage activation through adenosine receptor stimulation.

    Directory of Open Access Journals (Sweden)

    Peter A Keyel

    Full Text Available Regulation of inflammation is necessary to balance sufficient pathogen clearance with excessive tissue damage. Central to regulating inflammation is the switch from a pro-inflammatory pathway to an anti-inflammatory pathway. Macrophages are well-positioned to initiate this switch, and as such are the target of multiple therapeutics. One such potential therapeutic is methylthioadenosine (MTA, which inhibits TNFα production following LPS stimulation. We found that MTA could block TNFα production by multiple TLR ligands. Further, it prevented surface expression of CD69 and CD86 and reduced NF-KB signaling. We then determined that the mechanism of this action by MTA is signaling through adenosine A2 receptors. A2 receptors and TLR receptors synergized to promote an anti-inflammatory phenotype, as MTA enhanced LPS tolerance. In contrast, IL-1β production and processing was not affected by MTA exposure. Taken together, these data demonstrate that MTA reprograms TLR activation pathways via adenosine receptors to promote resolution of inflammation.

  6. ERK5 activation by Gq-coupled muscarinic receptors is independent of receptor internalization and β-arrestin recruitment.

    Directory of Open Access Journals (Sweden)

    Guzmán Sánchez-Fernández

    Full Text Available G-protein-coupled receptors (GPCRs are known to activate both G protein- and β-arrestin-dependent signalling cascades. The initiation of mitogen-activated protein kinase (MAPK pathways is a key downstream event in the control of cellular functions including proliferation, differentiation, migration and apoptosis. Both G proteins and β-arrestins have been reported to mediate context-specific activation of ERK1/2, p38 and JNK MAPKs. Recently, the activation of ERK5 MAPK by Gq-coupled receptors has been described to involve a direct interaction between Gαq and two novel effectors, PKCζ and MEK5. However, the possible contribution of β-arrestin towards this pathway has not yet been addressed. In the present work we sought to investigate the role of receptor internalization processes and β-arrestin recruitment in the activation of ERK5 by Gq-coupled GPCRs. Our results show that ERK5 activation is independent of M1 or M3 muscarinic receptor internalization. Furthermore, we demonstrate that phosphorylation-deficient muscarinic M1 and M3 receptors are still able to fully activate the ERK5 pathway, despite their reported inability to recruit β-arrestins. Indeed, the overexpression of Gαq, but not that of β-arrestin1 or β-arrestin2, was found to potently enhance ERK5 activation by GPCRs, whereas silencing of β-arrestin2 expression did not affect the activation of this pathway. Finally, we show that a β-arrestin-biased mutant form of angiotensin II (SII; Sar1-Ile4-Ile8 AngII failed to promote ERK5 phosphorylation in primary cardiac fibroblasts, as compared to the natural ligand. Overall, this study shows that the activation of ERK5 MAPK by model Gq-coupled GPCRs does not depend on receptor internalization, β-arrestin recruitment or receptor phosphorylation but rather is dependent on Gαq-signalling.

  7. Androgen Receptor Involvement in Rat Amelogenesis: An Additional Way for Endocrine-Disrupting Chemicals to Affect Enamel Synthesis.

    Science.gov (United States)

    Jedeon, Katia; Loiodice, Sophia; Salhi, Khaled; Le Normand, Manon; Houari, Sophia; Chaloyard, Jessica; Berdal, Ariane; Babajko, Sylvie

    2016-11-01

    Endocrine-disrupting chemicals (EDCs) that interfere with the steroid axis can affect amelogenesis, leading to enamel hypomineralization similar to that of molar incisor hypomineralization, a recently described enamel disease. We investigated the sex steroid receptors that may mediate the effects of EDCs during rat amelogenesis. The expression of androgen receptor (AR), estrogen receptor (ER)-α, and progesterone receptor was dependent on the stage of ameloblast differentiation, whereas ERβ remained undetectable. AR was the only receptor selectively expressed in ameloblasts involved in final enamel mineralization. AR nuclear translocation and induction of androgen-responsive element-containing promoter activity upon T treatment, demonstrated ameloblast responsiveness to androgens. T regulated the expression of genes involved in enamel mineralization such as KLK4, amelotin, SLC26A4, and SLC5A8 but not the expression of genes encoding matrix proteins, which determine enamel thickness. Vinclozolin and to a lesser extent bisphenol A, two antiandrogenic EDCs that cause enamel defects, counteracted the actions of T. In conclusion, we show, for the first time, the following: 1) ameloblasts express AR; 2) the androgen signaling pathway is involved in the enamel mineralization process; and 3) EDCs with antiandrogenic effects inhibit AR activity and preferentially affect amelogenesis in male rats. Their action, through the AR pathway, may specifically and irreversibly affect enamel, potentially leading to the use of dental defects as a biomarker of exposure to environmental pollutants. These results are consistent with the steroid hormones affecting ameloblasts, raising the issue of the hormonal influence on amelogenesis and possible sexual dimorphism in enamel quality.

  8. 28 CFR 55.15 - Affected activities.

    Science.gov (United States)

    2010-07-01

    ... RIGHTS ACT REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.15 Affected... of applicable language minority groups to be effectively informed of and participate effectively...

  9. Kappa opioid receptor antagonist and N-methyl-D- aspartate receptor antagonist affect dynorphin- induced spinal cord electrophysiologic impairment

    Institute of Scientific and Technical Information of China (English)

    Yu Chen; Liangbi Xiang; Jun Liu; Dapeng Zhou; Hailong Yu; Qi Wang; Wenfeng Han; Weijian Ren

    2012-01-01

    The latencies of motor- and somatosensory-evoked potentials were prolonged to different degrees, and wave amplitude was obviously decreased, after injection of dynorphin into the rat subarachnoid cavity.The wave amplitude and latencies of motor- and somatosensory-evoked potentials were significantly recovered at 7 and 14 days after combined injection of dynorphin and either the kappa opioid receptor antagonist nor-binaltorphimine or the N-methyl-D-aspartate receptor antagonist MK-801.The wave amplitude and latency were similar in rats after combined injection of dynorphin and nor-binaltorphimine or MK-801.These results suggest that intrathecal injection of dynorphin causes damage to spinal cord function.Prevention of N-methyl-D-aspartate receptor or kappa receptor activation lessened the injury to spinal cord function induced by dynorphin.

  10. Peroxisome Proliferator Activated Receptors and Lipoprotein Metabolism

    Directory of Open Access Journals (Sweden)

    Sander Kersten

    2008-01-01

    Full Text Available Plasma lipoproteins are responsible for carrying triglycerides and cholesterol in the blood and ensuring their delivery to target organs. Regulation of lipoprotein metabolism takes place at numerous levels including via changes in gene transcription. An important group of transcription factors that mediates the effect of dietary fatty acids and certain drugs on plasma lipoproteins are the peroxisome proliferator activated receptors (PPARs. Three PPAR isotypes can be distinguished, all of which have a major role in regulating lipoprotein metabolism. PPARα is the molecular target for the fibrate class of drugs. Activation of PPARα in mice and humans markedly reduces hepatic triglyceride production and promotes plasma triglyceride clearance, leading to a clinically significant reduction in plasma triglyceride levels. In addition, plasma high-density lipoprotein (HDL-cholesterol levels are increased upon PPARα activation in humans. PPARγ is the molecular target for the thiazolidinedione class of drugs. Activation of PPARγ in mice and human is generally associated with a modest increase in plasma HDL-cholesterol and a decrease in plasma triglycerides. The latter effect is caused by an increase in lipoprotein lipase-dependent plasma triglyceride clearance. Analogous to PPARα, activation of PPARβ/δ leads to increased plasma HDL-cholesterol and decreased plasma triglyceride levels. In this paper, a fresh perspective on the relation between PPARs and lipoprotein metabolism is presented. The emphasis is on the physiological role of PPARs and the mechanisms underlying the effect of synthetic PPAR agonists on plasma lipoprotein levels.

  11. Low power laser irradiation does not affect the generation of signals in a sensory receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lundeberg, T.; Zhou, J.

    1989-01-01

    The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

  12. Drosophila insulin-producing cells are differentially modulated by serotonin and octopamine receptors and affect social behavior.

    Directory of Open Access Journals (Sweden)

    Jiangnan Luo

    Full Text Available A set of 14 insulin-producing cells (IPCs in the Drosophila brain produces three insulin-like peptides (DILP2, 3 and 5. Activity in IPCs and release of DILPs is nutrient dependent and controlled by multiple factors such as fat body-derived proteins, neurotransmitters, and neuropeptides. Two monoamine receptors, the octopamine receptor OAMB and the serotonin receptor 5-HT1A, are expressed by the IPCs. These receptors may act antagonistically on adenylate cyclase. Here we investigate the action of the two receptors on activity in and output from the IPCs. Knockdown of OAMB by targeted RNAi led to elevated Dilp3 transcript levels in the brain, whereas 5-HT1A knockdown resulted in increases of Dilp2 and 5. OAMB-RNAi in IPCs leads to extended survival of starved flies and increased food intake, whereas 5-HT1A-RNAi produces the opposite phenotypes. However, knockdown of either OAMB or 5-HT1A in IPCs both lead to increased resistance to oxidative stress. In assays of carbohydrate levels we found that 5-HT1A knockdown in IPCs resulted in elevated hemolymph glucose, body glycogen and body trehalose levels, while no effects were seen after OAMB knockdown. We also found that manipulations of the two receptors in IPCs affected male aggressive behavior in different ways and 5-HT1A-RNAi reduced courtship latency. Our observations suggest that activation of 5-HT1A and OAMB signaling in IPCs generates differential effects on Dilp transcription, fly physiology, metabolism and social interactions. However the findings do not support an antagonistic action of the two monoamines and their receptors in this particular system.

  13. Identification of Gene Markers for Activation of the Nuclear Receptor Pregnane X Receptor

    Science.gov (United States)

    Many environmentally-relevant chemicals and drugs activate the nuclear receptor pregnane X receptor (PXR). Activation of PXR in the mouse liver can lead to increases in liver weight in part through increased hepatocyte replication similar to chemicals that activate other nuclear ...

  14. In vitro neuronal network activity in NMDA receptor encephalitis

    Directory of Open Access Journals (Sweden)

    Jantzen Sabine U

    2013-02-01

    Full Text Available Abstract Background Anti-NMDA-encephalitis is caused by antibodies against the N-methyl-D-aspartate receptor (NMDAR and characterized by a severe encephalopathy with psychosis, epileptic seizures and autonomic disturbances. It predominantly occurs in young women and is associated in 59% with an ovarian teratoma. Results We describe effects of cerebrospinal fluid (CSF from an anti-N-methyl-D-aspartate receptor (NMDAR encephalitis patient on in vitro neuronal network activity (ivNNA. In vitro NNA of dissociated primary rat cortical populations was recorded by the microelectrode array (MEA system. The 23-year old patient was severely affected but showed an excellent recovery following multimodal immunomodulatory therapy and removal of an ovarian teratoma. Patient CSF (pCSF taken during the initial weeks after disease onset suppressed global spike- and burst rates of ivNNA in contrast to pCSF sampled after clinical recovery and decrease of NMDAR antibody titers. The synchrony of pCSF-affected ivNNA remained unaltered during the course of the disease. Conclusion Patient CSF directly suppresses global activity of neuronal networks recorded by the MEA system. In contrast, pCSF did not regulate the synchrony of ivNNA suggesting that NMDAR antibodies selectively regulate distinct parameters of ivNNA while sparing their functional connectivity. Thus, assessing ivNNA could represent a new technique to evaluate functional consequences of autoimmune encephalitis-related CSF changes.

  15. Associations between the oxytocin receptor gene (OXTR) and affect, loneliness and intelligence in normal subjects.

    Science.gov (United States)

    Lucht, Michael J; Barnow, Sven; Sonnenfeld, Christine; Rosenberger, Albert; Grabe, Hans Joergen; Schroeder, Winnie; Völzke, Henry; Freyberger, Harald J; Herrmann, Falko H; Kroemer, Heyo; Rosskopf, Dieter

    2009-08-01

    Associations of oxytocin receptor gene (OXTR) variants and autism spectrum disorders (ASD) have been reported in earlier studies; in one of the studies associations with IQ and daily living skills were found additionally. Variations of the oxytocin receptor gene might also regulate affect, attachment and separation beyond the diagnostic borders of autism. We tested hypotheses of associations between positive and negative affects and social and emotional loneliness (285 adults), IQ (117 adolescents) and polymorphisms of the oxytocin receptor gene (OXTR rs53576, rs2254298 and rs2228485) in normal subjects. Individuals with the oxytocin OXTR rs53576 A/A genotype showed lower positive affect scores (F=5.532, df=1; p=0.019). This effect was restricted to males (F=13.098, df=1; p=0.00047). Haplotypes constructed with the three markers were associated with positive affect (p=0.0012), negative affect (p<0.0001) and emotional loneliness (p<0.0001). Non-verbal intelligence was significantly reduced in rs53576 A/A adolescents (T=2.247, p=0.027). Our findings support a role for the oxytocin receptor haplotypes in the generation of affectivity, emotional loneliness and IQ.

  16. Model for growth hormone receptor activation based on subunit rotation within a receptor dimer

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard J.; Adams, Julian J.; Pelekanos, Rebecca A.; Wan, Yu; McKinstry, William J.; Palethorpe, Kathryn; Seeber, Ruth M.; Monks, Thea A.; Eidne, Karin A.; Parker, Michael W.; Waters, Michael J. (UWA); (St. Vincent); (Queensland)

    2010-07-13

    Growth hormone is believed to activate the growth hormone receptor (GHR) by dimerizing two identical receptor subunits, leading to activation of JAK2 kinase associated with the cytoplasmic domain. However, we have reported previously that dimerization alone is insufficient to activate full-length GHR. By comparing the crystal structure of the liganded and unliganded human GHR extracellular domain, we show here that there is no substantial change in its conformation on ligand binding. However, the receptor can be activated by rotation without ligand by inserting a defined number of alanine residues within the transmembrane domain. Fluorescence resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET) and coimmunoprecipitation studies suggest that receptor subunits undergo specific transmembrane interactions independent of hormone binding. We propose an activation mechanism involving a relative rotation of subunits within a dimeric receptor as a result of asymmetric placement of the receptor-binding sites on the ligand.

  17. Calcium is the switch in the moonlighting dual function of the ligand-activated receptor kinase phytosulfokine receptor 1

    KAUST Repository

    Muleya, Victor

    2014-09-23

    Background: A number of receptor kinases contain guanylate cyclase (GC) catalytic centres encapsulated in the cytosolic kinase domain. A prototypical example is the phytosulfokine receptor 1 (PSKR1) that is involved in regulating growth responses in plants. PSKR1 contains both kinase and GC activities however the underlying mechanisms regulating the dual functions have remained elusive. Findings: Here, we confirm the dual activity of the cytoplasmic domain of the PSKR1 receptor. We show that mutations within the guanylate cyclase centre modulate the GC activity while not affecting the kinase catalytic activity. Using physiologically relevant Ca2+ levels, we demonstrate that its GC activity is enhanced over two-fold by Ca2+ in a concentration-dependent manner. Conversely, increasing Ca2+ levels inhibits kinase activity up to 500-fold at 100 nM Ca2+. Conclusions: Changes in calcium at physiological levels can regulate the kinase and GC activities of PSKR1. We therefore propose a functional model of how calcium acts as a bimodal switch between kinase and GC activity in PSKR1 that could be relevant to other members of this novel class of ligand-activated receptor kinases.

  18. Dual activities of odorants on olfactory and nuclear hormone receptors.

    Science.gov (United States)

    Pick, Horst; Etter, Sylvain; Baud, Olivia; Schmauder, Ralf; Bordoli, Lorenza; Schwede, Torsten; Vogel, Horst

    2009-10-30

    We have screened an odorant compound library and discovered molecules acting as chemical signals that specifically activate both G-protein-coupled olfactory receptors (ORs) on the cell surface of olfactory sensory neurons and the human nuclear estrogen receptor alpha (ER) involved in transcriptional regulation of cellular differentiation and proliferation in a wide variety of tissues. Hence, these apparent dual active odorants induce distinct signal transduction pathways at different subcellular localizations, which affect both neuronal signaling, resulting in odor perception, and the ER-dependent transcriptional control of specific genes. We demonstrate these effects using fluorescence-based in vitro and cellular assays. Among these odorants, we have identified synthetic sandalwood compounds, an important class of molecules used in the fragrance industry. For one estrogenic odorant we have also identified the cognate OR. This prompted us to compare basic molecular recognition principles of odorants on the two structurally and apparent functionally non-related receptors using computational modeling in combination with functional assays. Faced with the increasing evidence that ORs may perform chemosensory functions in a number of tissues outside of the nasal olfactory epithelium, the unraveling of these molecular ligand-receptor interaction principles is of critical importance. In addition the evidence that certain olfactory sensory neurons naturally co-express ORs and ERs may provide a direct functional link between the olfactory and hormonal systems in humans. Our results are therefore useful for defining the structural and functional characteristics of ER-specific odorants and the role of odorant molecules in cellular processes other than olfaction.

  19. Recruitment of activation receptors at inhibitory NK cell immune synapses.

    Directory of Open Access Journals (Sweden)

    Nicolas Schleinitz

    Full Text Available Natural killer (NK cell activation receptors accumulate by an actin-dependent process at cytotoxic immune synapses where they provide synergistic signals that trigger NK cell effector functions. In contrast, NK cell inhibitory receptors, including members of the MHC class I-specific killer cell Ig-like receptor (KIR family, accumulate at inhibitory immune synapses, block actin dynamics, and prevent actin-dependent phosphorylation of activation receptors. Therefore, one would predict inhibition of actin-dependent accumulation of activation receptors when inhibitory receptors are engaged. By confocal imaging of primary human NK cells in contact with target cells expressing physiological ligands of NK cell receptors, we show here that this prediction is incorrect. Target cells included a human cell line and transfected Drosophila insect cells that expressed ligands of NK cell activation receptors in combination with an MHC class I ligand of inhibitory KIR. The two NK cell activation receptors CD2 and 2B4 accumulated and co-localized with KIR at inhibitory immune synapses. In fact, KIR promoted CD2 and 2B4 clustering, as CD2 and 2B4 accumulated more efficiently at inhibitory synapses. In contrast, accumulation of KIR and of activation receptors at inhibitory synapses correlated with reduced density of the integrin LFA-1. These results imply that inhibitory KIR does not prevent CD2 and 2B4 signaling by blocking their accumulation at NK cell immune synapses, but by blocking their ability to signal within inhibitory synapses.

  20. Dopamine receptor activation increases HIV entry into primary human macrophages.

    Directory of Open Access Journals (Sweden)

    Peter J Gaskill

    Full Text Available Macrophages are the primary cell type infected with HIV in the central nervous system, and infection of these cells is a major component in the development of neuropathogenesis and HIV-associated neurocognitive disorders. Within the brains of drug abusers, macrophages are exposed to increased levels of dopamine, a neurotransmitter that mediates the addictive and reinforcing effects of drugs of abuse such as cocaine and methamphetamine. In this study we examined the effects of dopamine on HIV entry into primary human macrophages. Exposure to dopamine during infection increased the entry of R5 tropic HIV into macrophages, irrespective of the concentration of the viral inoculum. The entry pathway affected was CCR5 dependent, as antagonizing CCR5 with the small molecule inhibitor TAK779 completely blocked entry. The effect was dose-dependent and had a steep threshold, only occurring above 108 M dopamine. The dopamine-mediated increase in entry required dopamine receptor activation, as it was abrogated by the pan-dopamine receptor antagonist flupenthixol, and could be mediated through both subtypes of dopamine receptors. These findings indicate that the effects of dopamine on macrophages may have a significant impact on HIV pathogenesis. They also suggest that drug-induced increases in CNS dopamine may be a common mechanism by which drugs of abuse with distinct modes of action exacerbate neuroinflammation and contribute to HIV-associated neurocognitive disorders in infected drug abusers.

  1. Thrombin-Mediated Direct Activation of Proteinase-Activated Receptor-2: Another Target for Thrombin Signaling.

    Science.gov (United States)

    Mihara, Koichiro; Ramachandran, Rithwik; Saifeddine, Mahmoud; Hansen, Kristina K; Renaux, Bernard; Polley, Danny; Gibson, Stacy; Vanderboor, Christina; Hollenberg, Morley D

    2016-05-01

    Thrombin is known to signal to cells by cleaving/activating a G-protein-coupled family of proteinase-activated receptors (PARs). The signaling mechanism involves the proteolytic unmasking of an N-terminal receptor sequence that acts as a tethered receptor-activating ligand. To date, the recognized targets of thrombin cleavage and activation for signaling are PAR1 and PAR4, in which thrombin cleaves at a conserved target arginine to reveal a tethered ligand. PAR2, which like PAR1 is also cleaved at an N-terminal arginine to unmask its tethered ligand, is generally regarded as a target for trypsin but not for thrombin signaling. We now show that thrombin, at concentrations that can be achieved at sites of acute injury or in a tumor microenvironment, can directly activate PAR2 vasorelaxation and signaling, stimulating calcium and mitogen-activated protein kinase responses along with triggeringβ-arrestin recruitment. Thus, PAR2 can be added alongside PAR1 and PAR4 to the targets, whereby thrombin can affect tissue function.

  2. GabaB receptors activation in the NTS blocks the glycemic responses induced by carotid body receptor stimulation.

    Science.gov (United States)

    Lemus, Mónica; Montero, Sergio; Cadenas, José Luis; Lara, José Jesús; Tejeda-Chávez, Héctor Rafael; Alvarez-Buylla, Ramón; de Alvarez-Buylla, Elena Roces

    2008-08-18

    The carotid body receptors participate in glucose regulation sensing glucose levels in blood entering the cephalic circulation. The carotid body receptors information, is initially processed within the nucleus tractus solitarius (NTS) and elicits changes in circulating glucose and brain glucose uptake. Previous work has shown that gamma-aminobutyric acid (GABA) in NTS modulates respiratory reflexes, but the role of GABA within NTS in glucose regulation remains unknown. Here we show that GABA(B) receptor agonist (baclofen) or antagonists (phaclofen and CGP55845A) locally injected into NTS modified arterial glucose levels and brain glucose retention. Control injections outside NTS did not elicit these responses. In contrast, GABA(A) agonist and antagonist (muscimol or bicuculline) produced no significant changes in blood glucose levels. When these GABAergic drugs were applied before carotid body receptors stimulation, again, only GABA(B) agonist or antagonist significantly affected glycemic responses; baclofen microinjection significantly reduced the hyperglycemic response and brain glucose retention observed after carotid body receptors stimulation, while phaclofen produced the opposite effect, increasing significantly hyperglycemia and brain glucose retention. These results indicate that activation of GABA(B), but not GABA(A), receptors in the NTS modulates the glycemic responses after anoxic stimulation of the carotid body receptors, and suggest the presence of a tonic inhibitory mechanism in the NTS to avoid hyperglycemia.

  3. How do different types of physical activity affect mode?

    OpenAIRE

    高橋, 信二; 坂入, 洋右; 吉田, 雄大; 木塚, 朝博

    2012-01-01

    Generally, typical physical activities (e.g. walking and cycling) increase positive affect and decrease negative affect. However, few studies have investigated the effects on mood of activities that are frequently pursued during leisure time (e.g. dynamic stretching and video games). The purpose of the present study was to investigate the influences of different types of physical activity on mood. We selected 16 activities (kendama, active video games ["Wii Sports" tennis, baseball, boxing], ...

  4. Synthetic Ligands of Cannabinoid Receptors Affect Dauer Formation in the Nematode Caenorhabditis elegans

    Science.gov (United States)

    Reis Rodrigues, Pedro; Kaul, Tiffany K.; Ho, Jo-Hao; Lucanic, Mark; Burkewitz, Kristopher; Mair, William B.; Held, Jason M.; Bohn, Laura M.; Gill, Matthew S.

    2016-01-01

    Under adverse environmental conditions the nematode Caenorhabditis elegans can enter an alternate developmental stage called the dauer larva. To identify lipophilic signaling molecules that influence this process, we screened a library of bioactive lipids and found that AM251, an antagonist of the human cannabinoid (CB) receptor, suppresses dauer entry in daf-2 insulin receptor mutants. AM251 acted synergistically with glucose supplementation indicating that the metabolic status of the animal influenced the activity of this compound. Similarly, loss of function mutations in the energy-sensing AMP-activated kinase subunit, aak-2, enhanced the dauer-suppressing effects of AM251, while constitutive activation of aak-2 in neurons was sufficient to inhibit AM251 activity. Chemical epistasis experiments indicated that AM251 acts via G-protein signaling and requires the TGF-β ligand DAF-7, the insulin peptides DAF-28 and INS-6, and a functional ASI neuron to promote reproductive growth. AM251 also required the presence of the SER-5 serotonin receptor, but in vitro experiments suggest that this may not be via a direct interaction. Interestingly, we found that other antagonists of mammalian CB receptors also suppress dauer entry, while the nonselective CB receptor agonist, O-2545, not only inhibited the activity of AM251, but also was able to promote dauer entry when administered alone. Since worms do not have obvious orthologs of CB receptors, the effects of synthetic CBs on neuroendocrine signaling in C. elegans are likely to be mediated via another, as yet unknown, receptor mechanism. However, we cannot exclude the existence of a noncanonical CB receptor in C. elegans. PMID:27172180

  5. Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity.

    Science.gov (United States)

    Ichinose, Tomoko K; O'Leary, Donal S; Scislo, Tadeusz J

    2009-04-01

    The role of nucleus of solitary tract (NTS) A(2a) adenosine receptors in baroreflex mechanisms is controversial. Stimulation of these receptors releases glutamate within the NTS and elicits baroreflex-like decreases in mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), whereas inhibition of these receptors attenuates HR baroreflex responses. In contrast, stimulation of NTS A(2a) adenosine receptors increases preganglionic adrenal sympathetic nerve activity (pre-ASNA), and the depressor and sympathoinhibitory responses are not markedly affected by sinoaortic denervation and blockade of NTS glutamatergic transmission. To elucidate the role of NTS A(2a) adenosine receptors in baroreflex function, we compared full baroreflex stimulus-response curves for HR, RSNA, and pre-ASNA (intravenous nitroprusside/phenylephrine) before and after bilateral NTS microinjections of selective adenosine A(2a) receptor agonist (CGS-21680; 2.0, 20 pmol/50 nl), selective A(2a) receptor antagonist (ZM-241385; 40 pmol/100 nl), and nonselective A(1) + A(2a) receptor antagonist (8-SPT; 1 nmol/100 nl) in urethane/alpha-chloralose anesthetized rats. Activation of A(2a) receptors decreased the range, upper plateau, and gain of baroreflex-response curves for RSNA, whereas these parameters all increased for pre-ASNA, consistent with direct effects of the agonist on regional sympathetic activity. However, no resetting of baroreflex-response curves along the MAP axis occurred despite the marked decreases in baseline MAP. The antagonists had no marked effects on baseline variables or baroreflex-response functions. We conclude that the activation of NTS A(2a) adenosine receptors differentially alters baroreflex control of HR, RSNA, and pre-ASNA mostly via non-baroreflex mechanism(s), and these receptors have virtually no tonic action on baroreflex control of these sympathetic outputs.

  6. Gamma-hydroxybutyrate (GHB) induces cognitive deficits and affects GABAB receptors and IGF-1 receptors in male rats.

    Science.gov (United States)

    Johansson, Jenny; Grönbladh, Alfhild; Hallberg, Mathias

    2014-08-01

    In recent years, the abuse of the club drug gamma-hydroxybutyrate (GHB) has become increasingly popular among adolescents. The drug induces euphoria but can also result in sedation, anaesthesia as well as short-term amnesia. In addition, the abuse of GHB causes cognitive impairments and the mechanism by which GHB induces these impairments is not clarified. The present study investigates the impact of GHB treatment on spatial learning and memory using a water maze (WM) test in rats. Furthermore, the behavioural data is combined with an autoradiographic analysis of the GABAB and the IGF-1 receptor systems. The results demonstrate that the animals administered with GHB display an impaired performance in the WM test as compared to controls. In addition, significant alterations in GABAB and IGF-1 receptor density as well as GABAB receptor functionality, were observed in several brain regions associated with cognitive functions e.g. hippocampus. To conclude, our findings suggest that GHB treatment can affect spatial learning and memory, and that this outcome at least to some extent is likely to involve both GABAB and IGF-1 receptors.

  7. Cell death sensitization of leukemia cells by opioid receptor activation

    Science.gov (United States)

    Friesen, Claudia; Roscher, Mareike; Hormann, Inis; Fichtner, Iduna; Alt, Andreas; Hilger, Ralf A.; Debatin, Klaus-Michael; Miltner, Erich

    2013-01-01

    Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies. PMID:23633472

  8. Activation of glucocorticoid receptors increases 5-HT2A receptor levels

    DEFF Research Database (Denmark)

    Trajkovska, Viktorija; Kirkegaard, Lisbeth; Krey, Gesa;

    2009-01-01

    Major depression is associated with both dysregulation of the hypothalamic pituitary adrenal axis and serotonergic deficiency, not the least of the 5-HT2A receptor. However, how these phenomena are linked to each other, and whether a low 5-HT2A receptor level is a state or a trait marker...... of depression is unknown. In mice with altered glucocorticoid receptor (GR) expression we investigated 5-HT2A receptor levels by Western blot and 3H-MDL100907 receptor binding. Serotonin fibre density was analyzed by stereological quantification of serotonin transporter immunopositive fibers. To establish...... an effect of GR activation on 5-HT2A levels, mature organotypic hippocampal cultures were exposed to corticosterone with or without GR antagonist mifepristone and mineralocorticoid receptor (MR) antagonist spironolactone. In GR under-expressing mice, hippocampal 5-HT2A receptor protein levels were decreased...

  9. Allosteric regulation of G protein-coupled receptor activity by phospholipids.

    Science.gov (United States)

    Dawaliby, Rosie; Trubbia, Cataldo; Delporte, Cédric; Masureel, Matthieu; Van Antwerpen, Pierre; Kobilka, Brian K; Govaerts, Cédric

    2016-01-01

    Lipids are emerging as key regulators of membrane protein structure and activity. These effects can be attributed either to the modification of bilayer properties (thickness, curvature and surface tension) or to the binding of specific lipids to the protein surface. For G protein-coupled receptors (GPCRs), the effects of phospholipids on receptor structure and activity remain poorly understood. Here we reconstituted purified β2-adrenergic receptor (β2R) in high-density lipoparticles to systematically characterize the effect of biologically relevant phospholipids on receptor activity. We observed that the lipid headgroup type affected ligand binding (agonist and antagonist) and receptor activation. Specifically, phosphatidylgycerol markedly favored agonist binding and facilitated receptor activation, whereas phosphatidylethanolamine favored antagonist binding and stabilized the inactive state of the receptor. We then showed that these effects could be recapitulated with detergent-solubilized lipids, demonstrating that the functional modulation occurred in the absence of a bilayer. Our data suggest that phospholipids act as direct allosteric modulators of GPCR activity.

  10. Differential S1P Receptor Profiles on M1- and M2-Polarized Macrophages Affect Macrophage Cytokine Production and Migration

    Science.gov (United States)

    Müller, Jan; von Bernstorff, Wolfram; Heidecke, Claus-Dieter

    2017-01-01

    Introduction. Macrophages are key players in complex biological processes. In response to environmental signals, macrophages undergo polarization towards a proinflammatory (M1) or anti-inflammatory (M2) phenotype. Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid that acts via 5 G-protein coupled receptors (S1P1–5) in order to influence a broad spectrum of biological processes. This study assesses S1P receptor expression on macrophages before and after M1 and M2 polarization and performs a comparative analysis of S1P signalling in the two activational states of macrophages. Methods. Bone marrow derived macrophages (BMDM) from C57 BL/6 mice were cultured under either M1- or M2-polarizing conditions. S1P-receptor expression was determined by quantitative RT-PCR. Influence of S1P on macrophage activation, migration, phagocytosis, and cytokine secretion was assessed in vitro. Results. All 5 S1P receptor subclasses were expressed in macrophages. Culture under both M1- and M2-polarizing conditions led to significant downregulation of S1P1. In contrast, M1-polarized macrophages significantly downregulated S1P4. The expression of the remaining three S1P receptors did not change. S1P increased expression of iNOS under M2-polarizing conditions. Furthermore, S1P induced chemotaxis in M1 macrophages and changed cytokine production in M2 macrophages. Phagocytosis was not affected by S1P-signalling. Discussion. The expression of different specific S1P receptor profiles may provide a possibility to selectively influence M1- or M2-polarized macrophages.

  11. Biologically active extracts with kidney affections applications

    Science.gov (United States)

    Pascu (Neagu), Mihaela; Pascu, Daniela-Elena; Cozea, Andreea; Bunaciu, Andrei A.; Miron, Alexandra Raluca; Nechifor, Cristina Aurelia

    2015-12-01

    This paper is aimed to select plant materials rich in bioflavonoid compounds, made from herbs known for their application performances in the prevention and therapy of renal diseases, namely kidney stones and urinary infections (renal lithiasis, nephritis, urethritis, cystitis, etc.). This paper presents a comparative study of the medicinal plant extracts composition belonging to Ericaceae-Cranberry (fruit and leaves) - Vaccinium vitis-idaea L. and Bilberry (fruit) - Vaccinium myrtillus L. Concentrated extracts obtained from medicinal plants used in this work were analyzed from structural, morphological and compositional points of view using different techniques: chromatographic methods (HPLC), scanning electronic microscopy, infrared, and UV spectrophotometry, also by using kinetic model. Liquid chromatography was able to identify the specific compounds of the Ericaceae family, present in all three extracts, arbutosid, as well as specific components of each species, mostly from the class of polyphenols. The identification and quantitative determination of the active ingredients from these extracts can give information related to their therapeutic effects.

  12. Functional characterization of protease-activated receptor -1 palmitoylation in receptor signaling and trafficking /

    OpenAIRE

    2014-01-01

    G protein-coupled receptors (GPCRs) are the largest family of signaling receptors that respond to diverse stimuli and regulate many physiological responses. GPCRs elicit their cellular responses by coupling to distinct subtypes of heterotrimeric G-proteins composed of G[alpha] and G[beta][gamma] subunits. Activated GPCRs undergo conformational changes that allow the receptor to exchange GDP for GTP on the G[alpha] subunit, which induces dissociation from the [beta][gamma] subunits and subsequ...

  13. Evidence that adiponectin receptor 1 activation exacerbates ischemic neuronal death

    Directory of Open Access Journals (Sweden)

    Thundyil John

    2010-08-01

    Full Text Available Abstract Background- Adiponectin is a hormone produced in and released from adipose cells, which has been shown to have anti-diabetic and anti-inflammatory actions in peripheral cells. Two cell surface adiponectin receptors (ADRs mediate the majority of the known biological actions of adiponectin. Thus far, ADR expression in the brain has been demonstrated in the arcuate and the paraventricular nucleus of hypothalamus, where its activation affects food intake. Recent findings suggest that levels of circulating adiponectin increase after an ischemic stroke, but the role of adiponectin receptor activation in stroke pathogenesis and its functional outcome is unclear. Methods- Ischemic stroke was induced in C57BL/6 mice by middle cerebral artery occlusion (MCAO for 1 h, followed by reperfusion. Primary cortical neuronal cultures were established from individual embryonic neocortex. For glucose deprivation (GD, cultured neurons were incubated in glucose-free Locke's medium for 6, 12 or 24 h. For combined oxygen and glucose deprivation (OGD, neurons were incubated in glucose-free Locke's medium in an oxygen-free chamber with 95% N2/5% CO2 atmosphere for either 3, 6, 9, 12 or 24 h. Primary neurons and brain tissues were analysed for Adiponectin and ADRs using reverse transcriptase polymerase chain reaction (RT-PCR, immunoblot and immunochemistry methods. Results- Cortical neurons express ADR1 and ADR2, and that the levels of ADR1 are increased in neurons in response to in vitro or in vivo ischemic conditions. Neurons treated with either globular or trimeric adiponectin exhibited increased vulnerability to oxygen and glucose deprivation which was associated with increased activation of a pro-apoptotic signaling cascade involving p38 mitogen-activated protein kinase (p38MAPK and AMP-activated protein kinase (AMPK. Conclusions- This study reveals a novel pathogenic role for adiponectin and adiponectin receptor activation in ischemic stroke. We show that

  14. The Orphan Nuclear Receptor TR4 Is a Vitamin A-activated Nuclear Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X. Edward; Suino-Powell, Kelly M.; Xu, Yong; Chan, Cee-Wah; Tanabe, Osamu; Kruse, Schoen W.; Reynolds, Ross; Engel, James Douglas; Xu, H. Eric (Michigan-Med); (Van Andel)

    2015-11-30

    Testicular receptors 2 and 4 (TR2/4) constitute a subgroup of orphan nuclear receptors that play important roles in spermatogenesis, lipid and lipoprotein regulation, and the development of the central nervous system. Currently, little is known about the structural features and the ligand regulation of these receptors. Here we report the crystal structure of the ligand-free TR4 ligand binding domain, which reveals an autorepressed conformation. The ligand binding pocket of TR4 is filled by the C-terminal half of helix 10, and the cofactor binding site is occupied by the AF-2 helix, thus preventing ligand-independent activation of the receptor. However, TR4 exhibits constitutive transcriptional activity on multiple promoters, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, or ligand binding substantially reduce the transcriptional activity of this receptor. Importantly, both retinol and retinoic acid are able to promote TR4 to recruit coactivators and to activate a TR4-regulated reporter. These findings demonstrate that TR4 is a ligand-regulated nuclear receptor and suggest that retinoids might have a much wider regulatory role via activation of orphan receptors such as TR4.

  15. The orphan nuclear receptor TR4 is a vitamin A-activated nuclear receptor.

    Science.gov (United States)

    Zhou, X Edward; Suino-Powell, Kelly M; Xu, Yong; Chan, Cee-Wah; Tanabe, Osamu; Kruse, Schoen W; Reynolds, Ross; Engel, James Douglas; Xu, H Eric

    2011-01-28

    Testicular receptors 2 and 4 (TR2/4) constitute a subgroup of orphan nuclear receptors that play important roles in spermatogenesis, lipid and lipoprotein regulation, and the development of the central nervous system. Currently, little is known about the structural features and the ligand regulation of these receptors. Here we report the crystal structure of the ligand-free TR4 ligand binding domain, which reveals an autorepressed conformation. The ligand binding pocket of TR4 is filled by the C-terminal half of helix 10, and the cofactor binding site is occupied by the AF-2 helix, thus preventing ligand-independent activation of the receptor. However, TR4 exhibits constitutive transcriptional activity on multiple promoters, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, or ligand binding substantially reduce the transcriptional activity of this receptor. Importantly, both retinol and retinoic acid are able to promote TR4 to recruit coactivators and to activate a TR4-regulated reporter. These findings demonstrate that TR4 is a ligand-regulated nuclear receptor and suggest that retinoids might have a much wider regulatory role via activation of orphan receptors such as TR4.

  16. Potentiation of gamma aminobutyric acid receptors (GABAAR by Ethanol: How are inhibitory receptors affected?

    Directory of Open Access Journals (Sweden)

    Benjamin eFörstera

    2016-05-01

    Full Text Available In recent years there has been an increase in the understanding of ethanol actions on the type A -aminobutyric acid chloride channel (GABAAR, a member of the pentameric ligand gated ion channels (pLGICs. However, the mechanism by which ethanol potentiates the complex is still not fully understood and a number of publications have shown contradictory results. Thus many questions still remain unresolved requiring further studies for a better comprehension of this effect. The present review concentrates on the involvement of GABAAR in the acute actions of ethanol and specifically focuses on the immediate, direct or indirect, synaptic and extra-synaptic modulatory effects. To elaborate on the immediate, direct modulation of GABAAR by acute ethanol exposure, electrophysiological studies investigating the importance of different subunits, and data from receptor mutants will be examined. We will also discuss the nature of the putative binding sites for ethanol based on structural data obtained from other members of the pLGICs family. Finally, we will briefly highlight the glycine gated chloride channel (GlyR, another member of the pLGIC family, as a suitable target for the development of new pharmacological tools.

  17. Palmitoylation of cysteine 415 of CB1 receptor affects ligand-stimulated internalization and selective interaction with membrane cholesterol and caveolin 1.

    Science.gov (United States)

    Oddi, Sergio; Stepniewski, Tomasz Maciej; Totaro, Antonio; Selent, Jana; Scipioni, Lucia; Dufrusine, Beatrice; Fezza, Filomena; Dainese, Enrico; Maccarrone, Mauro

    2017-02-12

    We previously demonstrated that CB1 receptor is palmitoylated at cysteine 415, and that such a post-translational modification affects its biological activity. To assess the molecular mechanisms responsible for modulation of CB1 receptor function by S-palmitoylation, in this study biochemical and morphological approaches were paralleled with computational analyses. Molecular dynamics simulations suggested that this acyl chain stabilizes helix 8 as well as the interaction of CB1 receptor with membrane cholesterol. In keeping with these in silico data, experimental results showed that the non-palmitoylated CB1 receptor was unable to interact efficaciously with caveolin 1, independently of its activation state. Moreover, in contrast with the wild-type receptor, the lack of S-palmitoylation in the helix 8 made the mutant CB1 receptor completely irresponsive to agonist-induced effects in terms of both lipid raft partitioning and receptor internalization. Overall, our results support the notion that palmitoylation of cysteine 415 modulates the conformational state of helix 8 and influences the interactions of CB1 receptor with cholesterol and caveolin 1, suggesting that the palmitoyl chain may serve as a functional interface for CB1 receptor localization and function.

  18. Tools and techniques to study ligand-receptor interactions and receptor activation by TNF superfamily members.

    Science.gov (United States)

    Schneider, Pascal; Willen, Laure; Smulski, Cristian R

    2014-01-01

    Ligands and receptors of the TNF superfamily are therapeutically relevant targets in a wide range of human diseases. This chapter describes assays based on ELISA, immunoprecipitation, FACS, and reporter cell lines to monitor interactions of tagged receptors and ligands in both soluble and membrane-bound forms using unified detection techniques. A reporter cell assay that is sensitive to ligand oligomerization can identify ligands with high probability of being active on endogenous receptors. Several assays are also suitable to measure the activity of agonist or antagonist antibodies, or to detect interactions with proteoglycans. Finally, self-interaction of membrane-bound receptors can be evidenced using a FRET-based assay. This panel of methods provides a large degree of flexibility to address questions related to the specificity, activation, or inhibition of TNF-TNF receptor interactions in independent assay systems, but does not substitute for further tests in physiologically relevant conditions.

  19. Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

    Science.gov (United States)

    2010-08-01

    molecular pathways through allosteric regulation of various proteins including proteases [39,40], the cannabinoid receptor 1 (CB1) [41], the a7 nicotinic...41. Price MR, Baillie GL, Thomas A, Stevenson LA, Easson M, et al. (2005) Allosteric modulation of the cannabinoid CB1 receptor . Mol Pharmacol 68...Insect Repellents: Modulators of Mosquito Odorant Receptor Activity Jonathan D. Bohbot, Joseph C. Dickens* Invasive Insect Biocontrol and Behavior

  20. Pinitol supplementation does not affect insulin-mediated glucose metabolism and muscle insulin receptor content and phosphorylation in older humans.

    Science.gov (United States)

    Campbell, Wayne W; Haub, Mark D; Fluckey, James D; Ostlund, Richard E; Thyfault, John P; Morse-Carrithers, Hannah; Hulver, Matthew W; Birge, Zonda K

    2004-11-01

    This study assessed the effect of oral pinitol supplementation on oral and intravenous glucose tolerances and on skeletal muscle insulin receptor content and phosphorylation in older people. Fifteen people (6 men, 9 women; age 66 +/- 8 y; BMI 27.9 +/- 3.3 kg/m(2); hemoglobin A1c 5.39 +/- 0.46%, mean +/- SD) completed a 7-wk protocol. Subjects were randomly assigned to groups that during wk 2-7 consumed twice daily either a non-nutritive beverage (Placebo group, n = 8) or the same beverage with 1000 mg pinitol dissolved into it (Pinitol group, n = 7, total dose = 2000 mg pinitol/d). Testing was done at wk 1 and wk 7. In the Pinitol group with supplementation, 24-h urinary pinitol excretion increased 17-fold. The fasting concentrations of glucose, insulin, and C-peptide, and the 180-min area under the curve for these compounds, in response to oral (75 g) and intravenous (300 mg/kg) glucose tolerance challenges, were unchanged from wk 1 to wk 7 and were not influenced by pinitol. Also, pinitol did not affect indices of hepatic and whole-body insulin sensitivity from the oral glucose tolerance test and indices of insulin sensitivity, acute insulin response to glucose, and glucose effectiveness from the intravenous glucose tolerance test, estimated using minimal modeling. Pinitol did not differentially affect total insulin receptor content and insulin receptor phosphotyrosine 1158 and insulin receptor phosphotyrosine 1162/1163 activation in vastus lateralis samples taken during an oral-glucose-induced hyperglycemic and hyperinsulinemic state. These data suggest that pinitol supplementation does not influence whole-body insulin-mediated glucose metabolism and muscle insulin receptor content and phosphorylation in nondiabetic, older people.

  1. Repressive effects of resveratrol on androgen receptor transcriptional activity.

    Directory of Open Access Journals (Sweden)

    Wen-feng Shi

    Full Text Available BACKGROUND: The chemopreventive effects of resveratrol (RSV on prostate cancer have been well established; the androgen receptor (AR plays pivotal roles in prostatic tumorigenesis. However, the exact underlying molecular mechanisms about the effects of RSV on AR have not been fully elucidated. A model system is needed to determine whether and how RSV represses AR transcriptional activity. METHODOLOGY: The AR cDNA was first cloned into the retroviral vector pOZ-N and then integrated into the genome of AR-negative HeLa cells to generate the AR(+ cells. The constitutively expressed AR was characterized by monitoring hormone-stimulated nuclear translocation, DNA binding, and transcriptional activation, with the AR(- cells serving as controls. AR(+ cells were treated with RSV, and both AR protein levels and AR transcriptional activity were measured simultaneously. Chromatin immunoprecipitation (ChIP assays were used to detect the effects of RSV on the recruitment of AR to its cognate element (ARE. RESULTS: AR in the AR (+ stable cell line functions in a manner similar to that of endogenously expressed AR. Using this model system we clearly demonstrated that RSV represses AR transcriptional activity independently of any effects on AR protein levels. However, neither the hormone-mediated nucleus translocation nor the AR/ARE interaction was affected by RSV treatment. CONCLUSION: We demonstrated unambiguously that RSV regulates AR target gene expression, at least in part, by repressing AR transcriptional activity. Repressive effects of RSV on AR activity result from mechanisms other than the affects of AR nuclear translocation or DNA binding.

  2. Human Immunodeficiency Syndromes Affecting Human Natural Killer Cell Cytolytic Activity

    OpenAIRE

    Ham, Hyoungjun; Billadeau, Daniel D.

    2014-01-01

    Natural killer (NK) cells are lymphocytes of the innate immune system that secrete cytokines upon activation and mediate the killing of tumor cells and virus-infected cells, especially those that escape the adaptive T cell response caused by the down regulation of MHC-I. The induction of cytotoxicity requires that NK cells contact target cells through adhesion receptors, and initiate activation signaling leading to increased adhesion and accumulation of F-actin at the NK cell cytotoxic synaps...

  3. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    OpenAIRE

    Maryam Rakhshandehroo; Bianca Knoch; Michael Müller; Sander Kersten

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPAR alpha) 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. PPAR alpha serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPAR alpha binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPAR alpha governs biologi...

  4. [Regulation of G protein-coupled receptor kinase activity].

    Science.gov (United States)

    Haga, T; Haga, K; Kameyama, K; Nakata, H

    1994-09-01

    Recent progress on the activation of G protein-coupled receptor kinases is reviewed. beta-Adrenergic receptor kinase (beta ARK) is activated by G protein beta gamma -subunits, which interact with the carboxyl terminal portion of beta ARK. Muscarinic receptor m2-subtypes are phosphorylated by beta ARK1 in the central part of the third intracellular loop (I3). Phosphorylation of I3-GST fusion protein by beta ARK1 is synergistically stimulated by the beta gamma -subunits and mastoparan or a peptide corresponding to portions adjacent to the transmembrane segments of m2-receptors or by beta gamma -subunits and the agonist-bound I3-deleted m2 variant. These results indicate that agonist-bound receptors serve as both substrates and activators of beta ARK.

  5. Protease-Activated Receptors and other G-Protein-Coupled Receptors: the Melanoma Connection

    OpenAIRE

    Rosero, Rebecca A.; Villares, Gabriel J.; Bar-Eli, Menashe

    2016-01-01

    The vast array of G-protein-coupled receptors (GPCRs) play crucial roles in both physiological and pathological processes, including vision, coagulation, inflammation, autophagy, and cell proliferation. GPCRs also affect processes that augment cell proliferation and metastases in many cancers including melanoma. Melanoma is the deadliest form of skin cancer, yet limited therapeutic modalities are available to patients with metastatic melanoma. Studies have found that both chemokine receptors ...

  6. Pharmacology of the hypothermic response to 5-HT1A receptor activation in humans.

    Science.gov (United States)

    Lesch, K P; Poten, B; Söhnle, K; Schulte, H M

    1990-01-01

    The selective 5-HT1A receptor ligand ipsapirone (IPS) caused dose-related hypothermia in humans. The response was attenuated by the nonselective 5-HT1/2 receptor antagonist metergoline and was completely antagonized by the nonselective beta-adrenoceptor antagonist pindolol, which interacts stereoselectively with the 5-HT1A receptor. The selective beta 1-adrenergic antagonist betaxolol had no effect. The findings indicate that IPS-induced hypothermia specifically involves activation of (presynaptic) 5-HT1A receptors. Therefore, the hypothermic response to IPS may provide a convenient in vivo paradigma to assess the function of the presynaptic 5-HT receptor in affective disorders and its involvement in the effects of psychotropic drugs.

  7. Ghrelin receptor deficiency does not affect diet-induced atherosclerosis in low-density lipoprotein receptor-null mice

    Directory of Open Access Journals (Sweden)

    Kirk M. Habegger

    2011-11-01

    Full Text Available Objective: Ghrelin, a stomach-derived, secreted peptide, and its receptor (growth hormone secretagogue receptor, GHSR are known to modulate food intake and energy homeostasis. The ghrelin system is also expressed broadly in cardiovascular tissues. Since ghrelin has been associated with anti-inflammatory and anti-atherogenic properties, but is also well known to promote obesity and impair glucose metabolism, we investigated whether ghrelin has any impact on the development of atherosclerosis. The hypothesis that endogenous ghrelin signaling may be involved in atherosclerosis has not been tested previously Methods and Results: We crossed ghrelin receptor knockout mice (GHSr-/- into a low-density lipoprotein receptor-null (Ldlr-/- mouse line. In this model, atherosclerotic lesions were promoted by feeding a high-fat, high-cholesterol Western-type diet for 13 months, following a standard protocol. Body composition and glucose homeostasis were similar between Ldlr-/- and Ldlr/GHSR -/- ko mice throughout the study. Absence or presence of GHSr did not alter the apolipoprotein profile changes in response to diet exposure on an LDLRko background. Atherosclerotic plaque volume in the aortic arch and thoracic aorta were also not affected differentially in mice without ghrelin signaling due to GHSR gene disruption as compared to control LDLRko littermates. In light of the associations reported for ghrelin with cardiovascular disease in humans, the lack of a phenotype in these loss-of- function studies in mice suggests no directly functional role for endogenous ghrelin in either the inhibition or the promotion of diet-induced atherosclerosis.Conclusions: These data indicate that, surprisingly, the complex and multifaceted actions of endogenous ghrelin signaling on the cardiovascular system have minimal direct impact on atherosclerotic plaque progression as based on loss-of-function in a mouse model of the disease.

  8. Structural basis for activation of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Gether, Ulrik; Asmar, Fazila; Meinild, Anne Kristine

    2002-01-01

    -type and mutant beta2-adrenergic receptors purified from Sf-9 insect cells. Our studies have also raised important questions regarding kinetics of receptors activation. These questions should be addressed in the future by application of techniques that will allow for simultaneous measurement of conformational...

  9. Endomorphins fully activate a cloned human mu opioid receptor.

    Science.gov (United States)

    Gong, J; Strong, J A; Zhang, S; Yue, X; DeHaven, R N; Daubert, J D; Cassel, J A; Yu, G; Mansson, E; Yu, L

    1998-11-13

    Endomorphins were recently identified as endogenous ligands with high selectivity for mu opioid receptors. We have characterized the ability of endomorphins to bind to and functionally activate the cloned human mu opioid receptor. Both endomorphin-1 and endomorphin-2 exhibited binding selectivity for the mu opioid receptor over the delta and kappa opioid receptors. Both agonists inhibited forskolin-stimulated increase of cAMP in a dose-dependent fashion. When the mu opioid receptor was coexpressed in Xenopus oocytes with G protein-activated K+ channels, application of either endomorphin activated an inward K+ current. This activation was dose-dependent and blocked by naloxone. Both endomorphins acted as full agonists with efficacy similar to that of [D-Ala2,N-Me-Phe4,Gly-ol5]enkephalin (DAMGO). These data indicate that endomorphins act as full agonists at the human mu opioid receptor, capable of stimulating the receptor to inhibit the cAMP/adenylyl cyclase pathway and activate G-protein-activated inwardly rectifying potassium (GIRK) channels.

  10. Activating Receptor Signals Drive Receptor Diversity in Developing Natural Killer Cells.

    Science.gov (United States)

    Freund, Jacquelyn; May, Rebecca M; Yang, Enjun; Li, Hongchuan; McCullen, Matthew; Zhang, Bin; Lenvik, Todd; Cichocki, Frank; Anderson, Stephen K; Kambayashi, Taku

    2016-08-01

    It has recently been appreciated that NK cells exhibit many features reminiscent of adaptive immune cells. Considerable heterogeneity exists with respect to the ligand specificity of individual NK cells and as such, a subset of NK cells can respond, expand, and differentiate into memory-like cells in a ligand-specific manner. MHC I-binding inhibitory receptors, including those belonging to the Ly49 and KIR families, are expressed in a variegated manner, which creates ligand-specific diversity within the NK cell pool. However, how NK cells determine which inhibitory receptors to express on their cell surface during a narrow window of development is largely unknown. In this manuscript, we demonstrate that signals from activating receptors are critical for induction of Ly49 and KIR receptors during NK cell development; activating receptor-derived signals increased the probability of the Ly49 bidirectional Pro1 promoter to transcribe in the forward versus the reverse direction, leading to stable expression of Ly49 receptors in mature NK cells. Our data support a model where the balance of activating and inhibitory receptor signaling in NK cells selects for the induction of appropriate inhibitory receptors during development, which NK cells use to create a diverse pool of ligand-specific NK cells.

  11. Interaction of chemokines with their receptors--from initial chemokine binding to receptor activating steps

    DEFF Research Database (Denmark)

    Thiele, Stefanie; Rosenkilde, Mette Marie

    2014-01-01

    interactions possibly occur, resulting in a multi-step process, as recently proposed for other 7TM receptors. Overall, the N-terminus of chemokine receptors is pivotal for binding of all chemokines. During receptor activation, differences between the two major chemokine subgroups occur, as CC-chemokines mainly......The human chemokine system comprises 19 seven-transmembrane helix (7TM) receptors and 45 endogenous chemokines that often interact with each other in a promiscuous manner. Due to the chemokine system's primary function in leukocyte migration, it has a central role in immune homeostasis...... and surveillance. Chemokines are a group of 8-12 kDa large peptides with a secondary structure consisting of a flexible N-terminus and a core-domain usually stabilized by two conserved disulfide bridges. They mainly interact with the extracellular domains of their cognate 7TM receptors. Affinityand activity...

  12. Role of NK1 and NK2 receptors in mouse gastric mechanical activity.

    Science.gov (United States)

    Mulè, Flavia; Amato, Antonella; Vannucchi, Maria Giuliana; Faussone-Pellegrini, Maria Simonetta; Serio, Rosa

    2006-02-01

    1. The aim of the present study was to examine the role of NK1 and NK2 receptors in the control of mechanical activity of mouse stomach. In this view, the motor effects induced by NK1 and NK2 receptor agonists and antagonists were analyzed, measuring motility as intraluminal pressure changes in mouse-isolated stomach preparations. In parallel, immunohistochemical studies were performed to identify the location of NK1 and NK2 receptors on myenteric neurons and smooth muscle cells. 2. Substance P (SP) induced biphasic effects: a contraction followed by relaxation; neurokinin A (NKA) and [beta-Ala8]-NKA(4-10), selective agonist of NK2 receptors, evoked concentration-dependent contractions, whereas [Sar9, Met(O2)11]-SP, selective agonist of NK1 receptors, induced concentration-dependent relaxation. 3. SR48968, NK2 receptor antagonist, did not modify the spontaneous activity and reduced the contractile effects induced by tachykinins without affecting the relaxation. SR140333, NK1 receptor antagonist, did not modify the spontaneous activity and antagonized the relaxant response to tachykinins, failing to affect the contractile effects. 4. The relaxation to SP or to [Sar9, Met(O2)11]-SP was abolished by tetrodotoxin (TTX) and significantly reduced by N(omega)-nitro-L-arginine methyl ester (L-NAME). 5. NK2-immunoreactivity (NK2-IR) was seen at the level of the smooth muscle cells of both circular and longitudinal muscle layers. NK1-immunoreactive (NK1-IR) neurons were seen in the myenteric ganglia and NK1/nNOS double labeling revealed that some neurons were both NK1-IR and nNOS-IR. 6. These results suggest that, in mouse stomach, NK1 receptors, causing relaxant responses, are present on nitrergic inhibitory myenteric neurons, whereas NK2 receptors, mediating contractile responses, are present at muscular level.

  13. Dosage-dependent effect of dopamine D2 receptor activation on motor cortex plasticity in humans.

    Science.gov (United States)

    Fresnoza, Shane; Stiksrud, Elisabeth; Klinker, Florian; Liebetanz, David; Paulus, Walter; Kuo, Min-Fang; Nitsche, Michael A

    2014-08-06

    The neuromodulator dopamine plays an important role in synaptic plasticity. The effects depend on receptor subtypes, affinity, concentration level, and the kind of neuroplasticity induced. In animal experiments, dopamine D2-like receptor stimulation revealed partially antagonistic effects on plasticity, which might be explained by dosage dependency. In humans, D2 receptor block abolishes plasticity, and the D2/D3, but predominantly D3, receptor agonist ropinirol has a dosage-dependent nonlinear affect on plasticity. Here we aimed to determine the specific affect of D2 receptor activation on neuroplasticity in humans, because physiological effects of D2 and D3 receptors might differ. Therefore, we combined application of the selective D2 receptor agonist bromocriptine (2.5, 10, and 20 mg or placebo medication) with anodal and cathodal transcranial direct current stimulation (tDCS), which induces nonfocal plasticity, and with paired associative stimulation (PAS) generating a more focal kind of plasticity in the motor cortex of healthy humans. Plasticity was monitored by transcranial magnetic stimulation-induced motor-evoked potential amplitudes. For facilitatory tDCS, bromocriptine prevented plasticity induction independent from drug dosage. However, its application resulted in an inverted U-shaped dose-response curve on inhibitory tDCS, excitability-diminishing PAS, and to a minor degree on excitability-enhancing PAS. These data support the assumption that modulation of D2-like receptor activity exerts a nonlinear dose-dependent effect on neuroplasticity in the human motor cortex that differs from predominantly D3 receptor activation and that the kind of plasticity-induction procedure is relevant for its specific impact.

  14. Glucocorticoid receptor and nuclear factor kappa-b affect three-dimensional chromatin organization

    NARCIS (Netherlands)

    Kuznetsova, T.; Wang, S.Y.; Rao, N.A.; Mandoli, A.; Martens, J.H.; Rother, N; Aartse, A.; Groh, L.; Janssen-Megens, E.M.; Li, G.; Ruan, Y.; Logie, C.; Stunnenberg, H.G.

    2015-01-01

    BACKGROUND: The impact of signal-dependent transcription factors, such as glucocorticoid receptor and nuclear factor kappa-b, on the three-dimensional organization of chromatin remains a topic of discussion. The possible scenarios range from remodeling of higher order chromatin architecture by activ

  15. Tonic activation of presynaptic GABAB receptors on rat pallidosubthalamic terminals

    Institute of Scientific and Technical Information of China (English)

    Lei CHEN; Wing-ho YUNG

    2005-01-01

    Aim: The subthalamic nucleus plays a critical role in the regulation of movement,and abnormal activity of its neurons is associated with some basal ganglia motor symptoms. We examined the presence of functional presynaptic GABAB receptors on pallidosubthalamic terminals and tested whether they were tonically active in the in vitro subthalamic slices. Methods: Whole-cell patch-clamp recordings were applied to acutely prepared rat subthalamic nucleus slices. The effects of specific GABAB agonist and antagonist on action potential-independent inhibitory postsynapfic currents (IPSCs), as well as holding current, were examined.Results: Superfusion of baclofen, a GABAB receptor agonist, significantly reduced the frequency of GABAA receptor-mediated miniature IPSCs (mIPSCs), in a Cd2+-sensitive manner, with no effect on the amplitude, indicating presynaptic inhibition on GABA release. In addition, baclofen induced a weak outward current only in a minority of subthalamic neurons. Both the pre- and post-synaptic effects of baclofen were prevented by the specific GABAB receptor antagonist,CGP55845. Furthermore, CGP55845 alone increased the frequency of mIPSCs,but had no effect on the holding current. Conclusion: These findings suggest the functional dominance of presynaptic GABAB receptors on the pallidosubthalamic terminals over the postsynaptic GABAB receptors on subthalamic neurons.Furthermore, the presynaptic, but not the postsynaptic, GABAB receptors are tonically active, suggesting that the presynaptic GABAB receptors in the subthalamic nucleus are potential therapeutic target for the treatment of Parkinson disease.

  16. Estrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a.

    Science.gov (United States)

    Seredynski, Aurore L; Balthazart, Jacques; Ball, Gregory F; Cornil, Charlotte A

    2015-09-23

    In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER-mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. Significance statement: The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute

  17. Structure and dynamics of a constitutively active neurotensin receptor

    Energy Technology Data Exchange (ETDEWEB)

    Krumm, Brian E. [National Inst. of Health (NIH), Rockville, MD (United States). National Inst. of Neurological Disorders and Stroke, Dept. of Health and Human Services; Lee, Sangbae [Beckman Research Inst. of the City of Hope, Duarte, CA (United States). Dept. of Molecular Immunology; Bhattacharya, Supriyo [Beckman Research Inst. of the City of Hope, Duarte, CA (United States). Dept. of Molecular Immunology; Botos, Istvan [National Inst. of Health (NIH), Bethesda, MD (United States). National Inst. of Diabetes and; White, Courtney F. [National Inst. of Health (NIH), Rockville, MD (United States). National Inst. of Neurological Disorders and Stroke, Dept. of Health and Human Services; Du, Haijuan [National Inst. of Health (NIH), Rockville, MD (United States). National Inst. of Neurological Disorders and Stroke, Dept. of Health and Human Services; Vaidehi, Nagarajan [Beckman Research Inst. of the City of Hope, Duarte, CA (United States). Dept. of Molecular Immunology; Grisshammer, Reinhard [National Inst. of Health (NIH), Rockville, MD (United States). National Inst. of Neurological Disorders and Stroke, Dept. of Health and Human Services

    2016-12-07

    Many G protein-coupled receptors show constitutive activity, resulting in the production of a second messenger in the absence of an agonist; and naturally occurring constitutively active mutations in receptors have been implicated in diseases. To gain insight into mechanistic aspects of constitutive activity, we report here the 3.3 Å crystal structure of a constitutively active, agonist-bound neurotensin receptor (NTSR1) and molecular dynamics simulations of agonist-occupied and ligand-free receptor. Comparison with the structure of a NTSR1 variant that has little constitutive activity reveals uncoupling of the ligand-binding domain from conserved connector residues, that effect conformational changes during GPCR activation. Furthermore, molecular dynamics simulations show strong contacts between connector residue side chains and increased flexibility at the intracellular receptor face as features that coincide with robust signalling in cells. The loss of correlation between the binding pocket and conserved connector residues, combined with altered receptor dynamics, possibly explains the reduced neurotensin efficacy in the constitutively active NTSR1 and a facilitated initial engagement with G protein in the absence of agonist.

  18. Activation of 5-HT7 receptors increases neuronal platelet-derived growth factor β receptor expression.

    Science.gov (United States)

    Vasefi, Maryam S; Kruk, Jeff S; Liu, Hui; Heikkila, John J; Beazely, Michael A

    2012-03-09

    Several antipsychotics have a high affinity for 5-HT7 receptors yet despite intense interest in the 5-HT7 receptor as a potential drug target to treat psychosis, the function and signaling properties of 5-HT7 receptors in neurons remain largely uncharacterized. In primary mouse hippocampal and cortical neurons, as well as in the SH-SY5Y cell line, incubation with 5-HT, 5-carboxamidotryptamine (5-CT), or 5-HT7 receptor-selective agonists increases the expression of platelet-derived growth factor (PDGF)β receptors. The increased PDGFβ receptor expression is cyclic AMP-dependent protein kinase (PKA)-dependent, suggesting that 5-HT7 receptors couple to Gα(s) in primary neurons. Interestingly, up-regulated PDGFβ receptors display an increased basal phosphorylation state at the phospholipase Cγ-activating tyrosine 1021. This novel linkage between the 5-HT7 receptor and the PDGF system may be an important GPCR-neurotrophic factor signaling pathway in neurons.

  19. Multiple switches in G protein-coupled receptor activation.

    Science.gov (United States)

    Ahuja, Shivani; Smith, Steven O

    2009-09-01

    The activation mechanism of G protein-coupled receptors has presented a puzzle that finally may be close to solution. These receptors have a relatively simple architecture consisting of seven transmembrane helices that contain just a handful of highly conserved amino acids, yet they respond to light and a range of chemically diverse ligands. Recent NMR structural studies on the active metarhodopsin II intermediate of the visual receptor rhodopsin, along with the recent crystal structure of the apoprotein opsin, have revealed multiple structural elements or 'switches' that must be simultaneously triggered to achieve full activation. The confluence of several required structural changes is an example of "coincidence counting", which is often used by nature to regulate biological processes. In ligand-activated G protein-coupled receptors, the presence of multiple switches may provide an explanation for the differences between full, partial and inverse agonists.

  20. 5-HT7 receptor activation promotes an increase in TrkB receptor expression and phosphorylation

    Directory of Open Access Journals (Sweden)

    Anshula eSamarajeewa

    2014-11-01

    Full Text Available The serotonin (5-HT type 7 receptor is expressed throughout the CNS including cortical neurons. We have previously demonstrated that the application of 5-HT7 receptor agonists to primary hippocampal neurons and SH-SY5Y cells increases platelet-derived growth factor (PDGF receptor expression and promotes neuroprotection against N-methyl-D-aspartate-(NMDA-induced toxicity. The tropomyosin-related kinase B (TrkB receptor is one of the receptors for brain-derived neurotrophic factor (BDNF and is associated with neurodevelopmental and neuroprotective effects. Application of LP 12 to primary cerebral cortical cultures, SH-SY5Y cells, as well as the retinal ganglion cell line, RGC-5, increased both the expression of full length TrkB as well as its basal phosphorylation state at tyrosine 816. The increase in TrkB expression and phosphorylation was observed as early as 30 min after 5-HT7 receptor activation. In addition to full-length TrkB, kinase domain-deficient forms may be expressed and act as dominant-negative proteins towards the full length receptor. We have identified distinct patterns of TrkB isoform expression across our cell lines and cortical cultures. Although TrkB receptor expression is regulated by cyclic AMP and Gαs-coupled GPCRs in several systems, we demonstrate that, depending on the model system, pathways downstream of both Gαs and Gα12 are involved in the regulation of TrkB expression by 5-HT7 receptors. Given the number of psychiatric and degenerative diseases associated with TrkB/BDNF deficiency and the current interest in developing 5-HT7 receptor ligands as pharmaceuticals, identifying signaling relationships between these two receptors will aid in our understanding of the potential therapeutic effects of 5-HT7 receptor ligands.

  1. 5-HT7 receptor activation promotes an increase in TrkB receptor expression and phosphorylation

    Science.gov (United States)

    Samarajeewa, Anshula; Goldemann, Lolita; Vasefi, Maryam S.; Ahmed, Nawaz; Gondora, Nyasha; Khanderia, Chandni; Mielke, John G.; Beazely, Michael A.

    2014-01-01

    The serotonin (5-HT) type 7 receptor is expressed throughout the CNS including the cortex and hippocampus. We have previously demonstrated that the application of 5-HT7 receptor agonists to primary hippocampal neurons and SH-SY5Y cells increases platelet-derived growth factor (PDGF) receptor expression and promotes neuroprotection against N-methyl-D-aspartate-(NMDA)-induced toxicity. The tropomyosin-related kinase B (TrkB) receptor is one of the receptors for brain-derived neurotrophic factor (BDNF) and is associated with neurodevelopmental and neuroprotective effects. Application of LP 12 to primary cerebral cortical cultures, SH-SY5Y cells, as well as the retinal ganglion cell line, RGC-5, increased both the expression of full length TrkB as well as its basal phosphorylation state at tyrosine 816. The increase in TrkB expression and phosphorylation was observed as early as 30 min after 5-HT7 receptor activation. In addition to full-length TrkB, kinase domain-deficient forms may be expressed and act as dominant-negative proteins toward the full length receptor. We have identified distinct patterns of TrkB isoform expression across our cell lines and cortical cultures. Although TrkB receptor expression is regulated by cyclic AMP and Gαs-coupled GPCRs in several systems, we demonstrate that, depending on the model system, pathways downstream of both Gαs and Gα12 are involved in the regulation of TrkB expression by 5-HT7 receptors. Given the number of psychiatric and degenerative diseases associated with TrkB/BDNF deficiency and the current interest in developing 5-HT7 receptor ligands as pharmaceuticals, identifying signaling relationships between these two receptors will aid in our understanding of the potential therapeutic effects of 5-HT7 receptor ligands. PMID:25426041

  2. 5-HT7 receptor activation promotes an increase in TrkB receptor expression and phosphorylation.

    Science.gov (United States)

    Samarajeewa, Anshula; Goldemann, Lolita; Vasefi, Maryam S; Ahmed, Nawaz; Gondora, Nyasha; Khanderia, Chandni; Mielke, John G; Beazely, Michael A

    2014-01-01

    The serotonin (5-HT) type 7 receptor is expressed throughout the CNS including the cortex and hippocampus. We have previously demonstrated that the application of 5-HT7 receptor agonists to primary hippocampal neurons and SH-SY5Y cells increases platelet-derived growth factor (PDGF) receptor expression and promotes neuroprotection against N-methyl-D-aspartate-(NMDA)-induced toxicity. The tropomyosin-related kinase B (TrkB) receptor is one of the receptors for brain-derived neurotrophic factor (BDNF) and is associated with neurodevelopmental and neuroprotective effects. Application of LP 12 to primary cerebral cortical cultures, SH-SY5Y cells, as well as the retinal ganglion cell line, RGC-5, increased both the expression of full length TrkB as well as its basal phosphorylation state at tyrosine 816. The increase in TrkB expression and phosphorylation was observed as early as 30 min after 5-HT7 receptor activation. In addition to full-length TrkB, kinase domain-deficient forms may be expressed and act as dominant-negative proteins toward the full length receptor. We have identified distinct patterns of TrkB isoform expression across our cell lines and cortical cultures. Although TrkB receptor expression is regulated by cyclic AMP and Gαs-coupled GPCRs in several systems, we demonstrate that, depending on the model system, pathways downstream of both Gαs and Gα12 are involved in the regulation of TrkB expression by 5-HT7 receptors. Given the number of psychiatric and degenerative diseases associated with TrkB/BDNF deficiency and the current interest in developing 5-HT7 receptor ligands as pharmaceuticals, identifying signaling relationships between these two receptors will aid in our understanding of the potential therapeutic effects of 5-HT7 receptor ligands.

  3. Activation of α7-containing nicotinic receptors on astrocytes triggers AMPA receptor recruitment to glutamatergic synapses.

    Science.gov (United States)

    Wang, Xulong; Lippi, Giordano; Carlson, David M; Berg, Darwin K

    2013-12-01

    Astrocytes, an abundant form of glia, are known to promote and modulate synaptic signaling between neurons. They also express α7-containing nicotinic acetylcholine receptors (α7-nAChRs), but the functional relevance of these receptors is unknown. We show here that stimulation of α7-nAChRs on astrocytes releases components that induce hippocampal neurons to acquire more α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors post-synaptically at glutamatergic synapses. The increase is specific in that no change is seen in synaptic NMDA receptor clusters or other markers for glutamatergic synapses, or in markers for GABAergic synapses. Moreover, the increases in AMPA receptors on the neuron surface are accompanied by increases in the frequency of spontaneous miniature synaptic currents mediated by the receptors and increases in the ratio of evoked synaptic currents mediated by AMPA versus NMDA receptors. This suggests that stimulating α7-nAChRs on astrocytes can convert 'silent' glutamatergic synapses to functional status. Astrocyte-derived thrombospondin is necessary but not sufficient for the effect, while tumor necrosis factor-α is sufficient but not necessary. The results identify astrocyte α7-nAChRs as a novel pathway through which nicotinic cholinergic signaling can promote the development of glutamatergic networks, recruiting AMPA receptors to post-synaptic sites and rendering the synapses more functional. We find that activation of nicotinic receptors on astrocytes releases a component that specifically recruits AMPA receptors to glutamatergic synapses. The recruitment appears to occur preferentially at what may be 'silent synapses', that is, synapses that have all the components required for glutamatergic transmission (including NMDA receptors) but lack sufficient AMPA receptors to generate a response. The results are unexpected and open up new possibilities for mechanisms underlying network formation and synaptic plasticity.

  4. Molecular Imaging Provides Novel Insights on Estrogen Receptor Activity in Mouse Brain

    Directory of Open Access Journals (Sweden)

    Alessia Stell

    2008-11-01

    Full Text Available Estrogen receptors have long been known to be expressed in several brain areas in addition to those directly involved in the control of reproductive functions. Investigations in humans and in animal models suggest a strong influence of estrogens on limbic and motor functions, yet the complexity and heterogeneity of neural tissue have limited our approaches to the full understanding of estrogen activity in the central nervous system. The aim of this study was to examine the transcriptional activity of estrogen receptors in the brain of male and female mice. Exploiting the ERE-Luc reporter mouse, we set up a novel, bioluminescence-based technique to study brain estrogen receptor transcriptional activity. Here we show, for the first time, that estrogen receptors are similarly active in male and female brains and that the estrous cycle affects estrogen receptor activity in regions of the central nervous system not known to be associated with reproductive functions. Because of its reproducibility and sensitivity, this novel bioluminescence application stands as a candidate as an innovative methodology for the study and development of drugs targeting brain estrogen receptors.

  5. 16 CFR 801.3 - Activities in or affecting commerce.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Activities in or affecting commerce. 801.3... in or affecting commerce. Section 7A(a)(1) is satisfied if any entity included within the acquiring person, or any entity included within the acquired person, is engaged in commerce or in any...

  6. Helix 11 Dynamics is Critical for Constitutive Androstane Receptor Activity

    OpenAIRE

    Wright, Edward; Busby, Scott A.; Wisecarver, Sarah; Vincent, Jeremy; Griffin, Patrick R.; Fernandez, Elias J.

    2011-01-01

    The constitutive androstane receptor (CAR) transactivation can occur in the absence of exogenous ligand and this activity is enhanced by agonists TCPOBOP and meclizine. We use biophysical and cell-based assays to show that increased activity of CAR(TCPOBOP) relative to CAR(meclizine) corresponds to a higher affinity of CAR(TCPOBOP) for the steroid receptor coactivator-1. Additionally, steady-state fluorescence spectra suggest conformational differences between CAR(TCPOBOP):RXR and CAR(meclizi...

  7. Activation of 5-HT6 receptors inhibits corticostriatal glutamatergic transmission.

    Science.gov (United States)

    Tassone, Annalisa; Madeo, Graziella; Schirinzi, Tommaso; Vita, Daniela; Puglisi, Francesca; Ponterio, Giulia; Borsini, Franco; Pisani, Antonio; Bonsi, Paola

    2011-09-01

    We investigated the effect of 5-HT6 receptor subtype activation on glutamatergic transmission by means of whole-cell patch-clamp electrophysiological recordings from medium spiny neurons of the striatum and layer V pyramidal neurons of the prefrontal cortex. To this aim, we took advantage of a novel ligand, ST1936, showing nM affinity and agonist activity at the 5-HT6 receptor subtype. Our data show that 5-HT6 receptor activation by ST1936 reduces the frequency of spontaneous excitatory postsynaptic currents, with an IC50 of 1.3 μM. Moreover, 5-HT6 receptor activation also reduced the amplitude of spontaneous excitatory postsynaptic currents recorded from medium spiny neurons, suggesting a mechanism of action involving postsynaptic 5-HT6 receptors, as further confirmed by the paired-pulse analysis on evoked excitatory postsynaptic currents and by recordings of miniature glutamatergic events. The inhibitory effect of ST1936 on glutamatergic transmission was prevented by the selective 5-HT6 receptor antagonist SB258585 and mimicked by a different agonist, WAY-181187. Conversely, in the cortex ST1936 reduced the frequency, but not the amplitude, of spontaneous excitatory postsynaptic currents suggesting a presynaptic or indirect effect of the 5-HT6 receptor.

  8. Breathing is affected by dopamine D2-like receptors in the basolateral amygdala.

    Science.gov (United States)

    Sugita, Toshihisa; Kanamaru, Mitsuko; Iizuka, Makito; Sato, Kanako; Tsukada, Setsuro; Kawamura, Mitsuru; Homma, Ikuo; Izumizaki, Masahiko

    2015-04-01

    The precise mechanisms underlying how emotions change breathing patterns remain unclear, but dopamine is a candidate neurotransmitter in the process of emotion-associated breathing. We investigated whether basal dopamine release occurs in the basolateral amygdala (BLA), where sensory-related inputs are received and lead to fear or anxiety responses, and whether D1- and D2-like receptor antagonists affect breathing patterns and dopamine release in the BLA. Adult male mice (C57BL/6N) were perfused with artificial cerebrospinal fluid, a D1-like receptor antagonist (SCH 23390), or a D2-like receptor antagonist ((S)-(-)-sulpiride) through a microdialysis probe in the BLA. Respiratory variables were measured using a double-chamber plethysmograph. Dopamine release was measured by an HPLC. Perfusion of (S)-(-)-sulpiride in the BLA, not SCH 23390, specifically decreased respiratory rate without changes in local release of dopamine. These results suggest that basal dopamine release in the BLA, at least partially, increases respiratory rates only through post-synaptic D2-like receptors, not autoreceptors, which might be associated with emotional responses.

  9. Screening of selected pesticides for oestrogen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Breinholt, Vibeke; Larsen, John Christian

    1999-01-01

    Twenty pesticides were tested for their ability to activate the oestrogen receptor in vitro using an,MCF7 cell proliferation assay and a Yeast Oestrogen Screen. The fungicides fenarimol, triadimefon, and triadimenol were identified as weak oestrogen receptor agonists, which at 10 mu M induces a 2...... published that support oestrogenic activity in the intact animal, Thus, from the present results Mie suggest that oestrogen receptor activation may not be an important mode of action for these compounds. The need to include at least two bioassays in a screening procedure and for combining in vitro.......0, 2.4, and 1.9-fold increase in proliferation of human MCF7 breast cancer cells (E3 clone). The relative proliferation efficiency (RPE) was 43-69%, indicating partial agonism at the oestrogen receptor. Several pesticides did not have any effect oil the proliferation response after 6 days of exposure...

  10. EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Reinbothe, Susann; Larsson, Anna-Maria; Vaapil, Marica; Wigerup, Caroline [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Sun, Jianmin [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Jögi, Annika [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Neumann, Drorit [Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Rönnstrand, Lars [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Påhlman, Sven, E-mail: sven.pahlman@med.lu.se [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel)

    2014-02-28

    Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα{sup +}) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.

  11. Molecular mechanisms of action of the soy isoflavones includes activation of promiscuous nuclear receptors. A review.

    Science.gov (United States)

    Ricketts, Marie-Louise; Moore, David D; Banz, William J; Mezei, Orsolya; Shay, Neil F

    2005-06-01

    Consumption of soy has been demonstrated to reduce circulating cholesterol levels, most notably reducing low-density lipoprotein (LDL) cholesterol levels in hypercholesterolemic individuals. The component or components that might be responsible for this effect is still a matter of debate or controversy among many researchers. Candidate agents include an activity of soy protein itself, bioactive peptides produced during the digestive process, or the soy isoflavones. Although soy intake may provide other health benefits including preventative or remediative effects on cancer, osteoporosis and symptoms of menopause, this review will focus on isoflavones as agents affecting lipid metabolism. Isoflavones were first discovered as a bioactive agent disrupting estrogen action in female sheep, thereby earning the often-used term 'phytoestrogens'. Subsequent work confirmed the ability of isoflavones to bind to estrogen receptors. Along with the cholesterol-lowering effect of soy intake, research that is more recent has pointed to a beneficial antidiabetic effect of soy intake, perhaps mediated by soy isoflavones. The two common categories of antidiabetic drugs acting on nuclear receptors known as peroxisome proliferator activated receptors (PPARs) are the fibrates and glitazones. We and others have recently asked the research question 'do the soy isoflavones have activities as either "phytofibrates" or "phytoglitazones"?' Such an activity should be able to be confirmed both in vivo and in vitro. In both the in vivo and in vitro cases, this action has indeed been confirmed. Further work suggests a possible action of isoflavones similar to the nonestrogenic ligands that bind the estrogen-related receptors (ERRs). Recently, these receptors have been demonstrated to contribute to lipolytic processes. Finally, evaluation of receptor activation studies suggests that thyroid receptor activation may provide additional clues explaining the metabolic action of isoflavones. The recent

  12. Activation of intracellular angiotensin AT₂ receptors induces rapid cell death in human uterine leiomyosarcoma cells.

    Science.gov (United States)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen; Zuhayra, Maaz; Schütze, Stefan; Steckelings, Ulrike M; Recanti, Chiara; Namsoleck, Pawel; Unger, Thomas; Culman, Juraj

    2015-05-01

    The presence of angiotensin type 2 (AT₂) receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT₂ receptors including their presence in mitochondria and their role in the induction of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT₂ receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high densities in mitochondria. Activation of the cell membrane AT₂ receptors by a concomitant treatment with angiotensin II and the AT₁ receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT₂ receptor agonist, Compound 21 (C21), penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT₂ receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped cell death, displayed activation of the mitochondrial apoptotic pathway, i.e. down-regulation of the Bcl-2 protein, induction of the Bax protein and activation of caspase-3. All quiescent SK-UT-1 cells died within 5 days after treatment with a single dose of C21. C21 was devoid of cytotoxic effects in proliferating SK-UT-1 cells and in quiescent HutSMC. Our results point to a new, unique approach enabling the elimination non-cycling uterine leiomyosarcoma cells providing that they over-express the AT₂ receptor.

  13. Nicotinic Receptor Activity Alters Synaptic Plasticity

    Directory of Open Access Journals (Sweden)

    John A. Dani

    2001-01-01

    Full Text Available Studies using specific agonists, antagonists, and lesions have shown that nicotinic cholinergic systems participate in attention, learning, and memory[1,2]. The nicotinic manipulations usually have the greatest influence on difficult tasks or on cognitively impaired subjects[2]. For example, Alzheimer's disease is characterized by a loss of cholinergic projections and nicotinic acetylcholine receptors (nAChRs in the cortex and hippocampus[3]. Nicotine skin patches can improve learning rates and attention in Alzheimer's patients[4].

  14. Modulation of β-catenin signaling by glucagon receptor activation.

    Directory of Open Access Journals (Sweden)

    Jiyuan Ke

    Full Text Available The glucagon receptor (GCGR is a member of the class B G protein-coupled receptor family. Activation of GCGR by glucagon leads to increased glucose production by the liver. Thus, glucagon is a key component of glucose homeostasis by counteracting the effect of insulin. In this report, we found that in addition to activation of the classic cAMP/protein kinase A (PKA pathway, activation of GCGR also induced β-catenin stabilization and activated β-catenin-mediated transcription. Activation of β-catenin signaling was PKA-dependent, consistent with previous reports on the parathyroid hormone receptor type 1 (PTH1R and glucagon-like peptide 1 (GLP-1R receptors. Since low-density-lipoprotein receptor-related protein 5 (Lrp5 is an essential co-receptor required for Wnt protein mediated β-catenin signaling, we examined the role of Lrp5 in glucagon-induced β-catenin signaling. Cotransfection with Lrp5 enhanced the glucagon-induced β-catenin stabilization and TCF promoter-mediated transcription. Inhibiting Lrp5/6 function using Dickkopf-1(DKK1 or by expression of the Lrp5 extracellular domain blocked glucagon-induced β-catenin signaling. Furthermore, we showed that Lrp5 physically interacted with GCGR by immunoprecipitation and bioluminescence resonance energy transfer assays. Together, these results reveal an unexpected crosstalk between glucagon and β-catenin signaling, and may help to explain the metabolic phenotypes of Lrp5/6 mutations.

  15. FGF receptor antagonism does not affect adipose tissue development in nutritionally induced obesity.

    Science.gov (United States)

    Scroyen, Ilse; Vranckx, Christine; Lijnen, Henri Roger

    2014-01-01

    The fibroblast growth factor (FGF)-FGF receptor (FGFR) system plays a role in angiogenesis and maintenance of vascular integrity, but its potential role in adipose tissue related angiogenesis and development is still unknown. Administration of SSR, a low molecular weight inhibitor of multiple FGFRs, did not significantly affect body weight nor weight of subcutaneous or gonadal (GON) fat, as compared with pair-fed control mice. Adipocyte hypertrophy and reduced adipocyte density were only observed in GON adipose tissues of treated mice. Adipose tissue angiogenesis was not affected by SSR treatment, as normalized blood vessel density was comparable in adipose tissues of both groups. Blocking the FGF-FGFR system in vivo does not markedly affect adipose tissue development in mice with nutritionally induced obesity.

  16. Estimation of the receptor-state affinity constants of ligands in functional studies using wild type and constitutively active mutant receptors: Implications for estimation of agonist bias.

    Science.gov (United States)

    Ehlert, Frederick J; Stein, Richard S L

    We describe a method for estimating the affinities of ligands for active and inactive states of a G protein-coupled receptor (GPCR). Our protocol involves measuring agonist-induced signaling responses of a wild type GPCR and a constitutively active mutant of it under control conditions and after partial receptor inactivation or reduced receptor expression. Our subsequent analysis is based on the assumption that the activating mutation increases receptor isomerization into the active state without affecting the affinities of ligands for receptor states. A means of confirming this assumption is provided. Global nonlinear regression analysis yields estimates of 1) the active (Kact) and inactive (Kinact) receptor-state affinity constants, 2) the isomerization constant of the unoccupied receptor (Kq-obs), and 3) the sensitivity constant of the signaling pathway (KE-obs). The latter two parameters define the output response of the receptor, and hence, their ratio (Kq-obs/KE) is a useful measure of system bias. If the cellular system is reasonably stable and the Kq-obs and KE-obs values of the signaling pathway are known, the Kact and Kinact values of additional agonists can be estimated in subsequent experiments on cells expressing the wild type receptor. We validated our method through computer simulation, an analytical proof, and analysis of previously published data. Our approach provides 1) a more meaningful analysis of structure-activity relationships, 2) a means of validating in silico docking experiments on active and inactive receptor structures and 3) an absolute, in contrast to relative, measure of agonist bias.

  17. Nuclear receptor corepressor-dependent repression of peroxisome-proliferator-activated receptor delta-mediated transactivation

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Nielsen, Curt A F; Neve, Søren

    2002-01-01

    delta-RXR alpha heterodimer bound to an acyl-CoA oxidase (ACO)-type peroxisome-proliferator response element recruited a glutathione S-transferase-NCoR fusion protein in a ligand-independent manner. Contrasting with most other nuclear receptors, PPAR delta was found to interact equally well......The nuclear receptor corepressor (NCoR) was isolated as a peroxisome-proliferator-activated receptor (PPAR) delta interacting protein using the yeast two-hybrid system. NCoR interacted strongly with the ligand-binding domain of PPAR delta, whereas interactions with the ligand-binding domains...

  18. Multiple activities of insect repellents on odorant receptors in mosquitoes

    Science.gov (United States)

    Several lines of evidence suggest that insect repellent molecules reduce mosquito-host contacts by interacting with odorants and odorant receptors (ORs) ultimately affecting olfactory-driven behaviors. We describe the molecular effects of ten insect repellents and a pyrethroid insecticide with known...

  19. Effects of histamine H1 receptor signaling on glucocorticoid receptor activity. Role of canonical and non-canonical pathways.

    Science.gov (United States)

    Zappia, Carlos Daniel; Granja-Galeano, Gina; Fernández, Natalia; Shayo, Carina; Davio, Carlos; Fitzsimons, Carlos P; Monczor, Federico

    2015-12-04

    Histamine H1 receptor (H1R) antagonists and glucocorticoid receptor (GR) agonists are used to treat inflammatory conditions such as allergic rhinitis, atopic dermatitis and asthma. Consistent with the high morbidity levels of such inflammatory conditions, these receptors are the targets of a vast number of approved drugs, and in many situations their ligands are co-administered. However, this drug association has no clear rationale and has arisen from clinical practice. We hypothesized that H1R signaling could affect GR-mediated activity, impacting on its transcriptional outcome. Indeed, our results show a dual regulation of GR activity by the H1R: a potentiation mediated by G-protein βγ subunits and a parallel inhibitory effect mediated by Gαq-PLC pathway. Activation of the H1R by its full agonists resulted in a composite potentiating effect. Intriguingly, inactivation of the Gαq-PLC pathway by H1R inverse agonists resulted also in a potentiation of GR activity. Moreover, histamine and clinically relevant antihistamines synergized with the GR agonist dexamethasone to induce gene transactivation and transrepression in a gene-specific manner. Our work provides a delineation of molecular mechanisms underlying the widespread clinical association of antihistamines and GR agonists, which may contribute to future dosage optimization and reduction of well-described side effects associated with glucocorticoid administration.

  20. Effects of histamine H1 receptor signaling on glucocorticoid receptor activity. Role of canonical and non-canonical pathways

    Science.gov (United States)

    Zappia, Carlos Daniel; Granja-Galeano, Gina; Fernández, Natalia; Shayo, Carina; Davio, Carlos; Fitzsimons, Carlos P.; Monczor, Federico

    2015-01-01

    Histamine H1 receptor (H1R) antagonists and glucocorticoid receptor (GR) agonists are used to treat inflammatory conditions such as allergic rhinitis, atopic dermatitis and asthma. Consistent with the high morbidity levels of such inflammatory conditions, these receptors are the targets of a vast number of approved drugs, and in many situations their ligands are co-administered. However, this drug association has no clear rationale and has arisen from clinical practice. We hypothesized that H1R signaling could affect GR-mediated activity, impacting on its transcriptional outcome. Indeed, our results show a dual regulation of GR activity by the H1R: a potentiation mediated by G-protein βγ subunits and a parallel inhibitory effect mediated by Gαq-PLC pathway. Activation of the H1R by its full agonists resulted in a composite potentiating effect. Intriguingly, inactivation of the Gαq-PLC pathway by H1R inverse agonists resulted also in a potentiation of GR activity. Moreover, histamine and clinically relevant antihistamines synergized with the GR agonist dexamethasone to induce gene transactivation and transrepression in a gene-specific manner. Our work provides a delineation of molecular mechanisms underlying the widespread clinical association of antihistamines and GR agonists, which may contribute to future dosage optimization and reduction of well-described side effects associated with glucocorticoid administration. PMID:26635083

  1. Analyzing the activation of the melanocortin-2 receptor of tetrapods.

    Science.gov (United States)

    Dores, Robert M; Liang, Liang

    2014-07-01

    Following the biochemical characterization of the pituitary hormone, adrenocorticotropin (ACTH), in the 1950's, a number of structure/function studies were done which identifies two amino acid motifs in ACTH, the HFRW motif and KKRR motif, as critical for the activation of the "ACTH" receptor on adrenal cortex cells. In the 1990's the "ACTH" receptor was identified as a member of the melanocortin receptor gene family, and given the name melanocortin-2 receptor (MC2R). Since that time a number of studies on both tetrapod and teleost MC2R orthologs have established that these orthologs can only be activated by ACTH, but not by any of the MSH-sized melanocortin ligands, and these orthologs require interaction with the melanocortin-2 receptor accessory protein (MRAP) for functional expression. This review summarizes recent structure/function studies on human ACTH, and points out the importance of the GKPVG motif in ACTH for the activation of the receptor. In this regard, a multiple-step model for the activation of tetrapod and teleost MC2R orthologs is presented, and the evolution of gnathostome MC2R ligand selectivity and the requirement for MRAP interaction is discussed in light of a recent study on a cartilaginous fish MC2R ortholog. This review contains excerpts from the Gorbman/Bern Lecture presented at the Second Meeting of the North American Society for Comparative Endocrinology (NASCE).

  2. Monitoring leptin activity using the chicken leptin receptor.

    Science.gov (United States)

    Hen, Gideon; Yosefi, Sera; Ronin, Ana; Einat, Paz; Rosenblum, Charles I; Denver, Robert J; Friedman-Einat, Miriam

    2008-05-01

    We report on the construction of a leptin bioassay based on the activation of chicken leptin receptor in cultured cells. A human embryonic kidney (HEK)-293 cell line, stably transfected with the full-length cDNA of chicken leptin receptor together with a STAT3-responsive reporter gene specifically responded to recombinant human and Xenopus leptins. The observed higher sensitivity of chicken leptin receptor to the former is in agreement with the degree of sequence similarity among these species (about 60 and 38% identical amino acids between humans and chickens, and between humans and Xenopus respectively). The specific activation of signal transduction through the chicken leptin receptor, shown here for the first time, suggests that the transition of Gln269 (implicated in the Gln-to-Pro Zucker fatty mutation in rats) to Glu in chickens does not impair its activity. Analysis of leptin-like activity in human serum samples of obese and lean subjects coincided well with leptin levels determined by RIA. Serum samples of pre- and post partum cows showed a tight correlation with the degree of adiposity. However, specific activation of the chicken leptin receptor in this assay was not observed with serum samples from broiler or layer chickens (representing fat and lean phenotypes respectively) or with those from turkey. Similar leptin receptor activation profiles were observed with cells transfected with human leptin receptor. Further work is needed to determine whether the lack of leptin-like activity in the chicken serum samples is due to a lack of leptin in this species or simply to a serum level of leptin that is below the detection threshold.

  3. A human vitamin D receptor mutant activated by cholecalciferol.

    Science.gov (United States)

    Ousley, Amanda M; Castillo, Hilda S; Duraj-Thatte, Anna; Doyle, Donald F; Azizi, Bahareh

    2011-07-01

    The human vitamin D receptor (hVDR) is a member of the nuclear receptor superfamily, involved in calcium and phosphate homeostasis; hence implicated in a number of diseases, such as Rickets and Osteoporosis. This receptor binds 1α,25-dihydroxyvitamin D(3) (also referred to as 1,25(OH)(2)D(3)) and other known ligands, such as lithocholic acid. Specific interactions between the receptor and ligand are crucial for the function and activation of this receptor, as implied by the single point mutation, H305Q, causing symptoms of Type II Rickets. In this work, further understanding of the significant and essential interactions between the ligand and the receptor was deciphered, through a combination of rational and random mutagenesis. A hVDR mutant, H305F, was engineered with increased sensitivity towards lithocholic acid, with an EC(50) value of 10 μM and 40±14 fold activation in mammalian cell assays, while maintaining wild-type activity with 1,25(OH)(2)D(3). Furthermore, via random mutagenesis, a hVDR mutant, H305F/H397Y, was discovered to bind a novel small molecule, cholecalciferol, a precursor in the 1α,25-dihydroxyvitamin D(3) biosynthetic pathway, which does not activate wild-type hVDR. This variant, H305F/H397Y, binds and activates in response to cholecalciferol concentrations as low as 100 nM, with an EC(50) value of 300 nM and 70±11 fold activation in mammalian cell assays. In silico docking analysis of the variant displays a dramatic conformational shift of cholecalciferol in the ligand binding pocket in comparison to the docked analysis of cholecalciferol with wild-type hVDR. This shift is hypothesized to be due to the introduction of two bulkier residues, suggesting that the addition of these bulkier residues introduces molecular interactions between the ligand and receptor, leading to activation with cholecalciferol.

  4. Activation and dynamic network of the M2 muscarinic receptor

    OpenAIRE

    Miao, Yinglong; Nichols, Sara E.; Gasper, Paul M.; Metzger, Vincent T; McCammon, J. Andrew

    2013-01-01

    G-protein-coupled receptors (GPCRs) mediate cellular responses to various hormones and neurotransmitters and are important targets for treating a wide spectrum of diseases. Although significant advances have been made in structural studies of GPCRs, details of their activation mechanism remain unclear. The X-ray crystal structure of the M2 muscarinic receptor, a key GPCR that regulates human heart rate and contractile forces of cardiomyocytes, was determined recently in an inactive antagonist...

  5. Possible association between the dopamine D3 receptor gene and bipolar affective disorder

    Energy Technology Data Exchange (ETDEWEB)

    Todd, R.D.; Chakraverty, S.; Parsian, A. [Washington Univ. School of Medicine, St. Louis, MO (United States)

    1994-09-01

    A variety of studies have reported possible genetic associations between bipolar affective disorder and different loci using relative risk approaches. An alternative approach is to determine untransmitted genotypes from families selected through a single affected individual. We have used both approaches to test for possible associations between alleles of the dopamine D3 receptor gene and bipolar affective disorder. For relative risk studies, the probands of multiple incidence bipolar affective disorder (n=66) and alcoholism (n=132) families and psychiatric normal controls (n=91) have been compared. Non-transmitted allele approaches have used bipolar affective disorder (n=28) and alcoholic (n=25) probands in which both parents were available for genotyping. Using the Bal I restriction enzyme site polymorphism of Lannfelt, we have found no differences in the allele or genotype frequencies for bipolar or alcoholic probands versus psychiatrically normal controls. In contrast, we have found evidence for an increased frequency of allele 1 and allele 1 containing genotypes in transmitted alleles from bipolar families.

  6. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    NARCIS (Netherlands)

    Rakhshandehroo, M.; Knoch, B.; Müller, M.R.; Kersten, A.H.

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPAR alpha) 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. PPAR alpha serves as a molecular target for hypolip

  7. Extended Synaptotagmin Interaction with the Fibroblast Growth Factor Receptor Depends on Receptor Conformation, Not Catalytic Activity.

    Science.gov (United States)

    Tremblay, Michel G; Herdman, Chelsea; Guillou, François; Mishra, Prakash K; Baril, Joëlle; Bellenfant, Sabrina; Moss, Tom

    2015-06-26

    We previously demonstrated that ESyt2 interacts specifically with the activated FGF receptor and is required for a rapid phase of receptor internalization and for functional signaling via the ERK pathway in early Xenopus embryos. ESyt2 is one of the three-member family of Extended Synaptotagmins that were recently shown to be implicated in the formation of endoplasmic reticulum (ER)-plasma membrane (PM) junctions and in the Ca(2+) dependent regulation of these junctions. Here we show that ESyt2 is directed to the ER by its putative transmembrane domain, that the ESyts hetero- and homodimerize, and that ESyt2 homodimerization in vivo requires a TM adjacent sequence but not the SMP domain. ESyt2 and ESyt3, but not ESyt1, selectively interact in vivo with activated FGFR1. In the case of ESyt2, this interaction requires a short TM adjacent sequence and is independent of receptor autophosphorylation, but dependent on receptor conformation. The data show that ESyt2 recognizes a site in the upper kinase lobe of FGFR1 that is revealed by displacement of the kinase domain activation loop during receptor activation.

  8. Activation of NTS A(1) adenosine receptors inhibits regional sympathetic responses evoked by activation of cardiopulmonary chemoreflex.

    Science.gov (United States)

    Ichinose, Tomoko K; Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2012-09-01

    Previously we have shown that adenosine operating via the A(1) receptor subtype may inhibit glutamatergic transmission in the baroreflex arc within the nucleus of the solitary tract (NTS) and differentially increase renal (RSNA), preganglionic adrenal (pre-ASNA), and lumbar (LSNA) sympathetic nerve activity (ASNA>RSNA≥LSNA). Since the cardiopulmonary chemoreflex and the arterial baroreflex are mediated via similar medullary pathways, and glutamate is a primary transmitter in both pathways, it is likely that adenosine operating via A(1) receptors in the NTS may differentially inhibit regional sympathetic responses evoked by activation of cardiopulmonary chemoreceptors. Therefore, in urethane-chloralose-anesthetized rats (n = 37) we compared regional sympathoinhibition evoked by the cardiopulmonary chemoreflex (activated with right atrial injections of serotonin 5HT(3) receptor agonist phenylbiguanide, PBG, 1-8 μg/kg) before and after selective stimulation of NTS A(1) adenosine receptors [microinjections of N(6)-cyclopentyl adenosine (CPA), 0.033-330 pmol/50 nl]. Activation of cardiopulmonary chemoreceptors evoked differential, dose-dependent sympathoinhibition (RSNA>ASNA>LSNA), and decreases in arterial pressure and heart rate. These differential sympathetic responses were uniformly attenuated in dose-dependent manner by microinjections of CPA into the NTS. Volume control (n = 11) and blockade of adenosine receptor subtypes in the NTS via 8-(p-sulfophenyl)theophylline (8-SPT, 1 nmol in 100 nl) (n = 9) did not affect the reflex responses. We conclude that activation of NTS A(1) adenosine receptors uniformly inhibits neural and cardiovascular cardiopulmonary chemoreflex responses. A(1) adenosine receptors have no tonic modulatory effect on this reflex under normal conditions. However, when adenosine is released into the NTS (i.e., during stress or severe hypotension/ischemia), it may serve as negative feedback regulator for depressor and sympathoinhibitory reflexes

  9. Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation

    DEFF Research Database (Denmark)

    Klein, H H; Müller, R; Vestergaard, H

    1999-01-01

    % of the receptors to become insulin-dependently activated. The mother carries a point mutation at the last base pair in exon 17 which, due to abnormal alternative splicing, could lead to normally transcribed receptor or truncated receptor lacking the kinase region. Kinase activation was normal in the mother......We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174-->Gln mutation, in situ......'s skeletal muscle, suggesting that virtually no truncated receptor was expressed. Receptor kinase activity was, however, reduced by 95 and 91% in the compound heterozygous brothers. This suggests that the mother's mutated allele contributes little to the generation of functional receptor protein...

  10. Antifibrotic effects of noscapine through activation of prostaglandin E2 receptors and protein kinase A.

    Science.gov (United States)

    Kach, Jacob; Sandbo, Nathan; La, Jennifer; Denner, Darcy; Reed, Eleanor B; Akimova, Olga; Koltsova, Svetlana; Orlov, Sergei N; Dulin, Nickolai O

    2014-03-14

    Myofibroblast differentiation is a key process in the pathogenesis of fibrotic disease. We have shown previously that differentiation of myofibroblasts is regulated by microtubule polymerization state. In this work, we examined the potential antifibrotic effects of the antitussive drug, noscapine, recently found to bind microtubules and affect microtubule dynamics. Noscapine inhibited TGF-β-induced differentiation of cultured human lung fibroblasts (HLFs). Therapeutic noscapine treatment resulted in a significant attenuation of pulmonary fibrosis in the bleomycin model of the disease. Noscapine did not affect gross microtubule content in HLFs, but inhibited TGF-β-induced stress fiber formation and activation of serum response factor without affecting Smad signaling. Furthermore, noscapine stimulated a rapid and profound activation of protein kinase A (PKA), which mediated the antifibrotic effect of noscapine in HLFs, as assessed with the PKA inhibitor, PKI. In contrast, noscapine did not activate PKA in human bronchial or alveolar epithelial cells. Finally, activation of PKA and the antifibrotic effect of noscapine in HLFs were blocked by the EP2 prostaglandin E2 receptor antagonist, PF-04418948, but not by the antagonists of EP4, prostaglandin D2, or prostacyclin receptors. Together, we demonstrate for the first time the antifibrotic effect of noscapine in vitro and in vivo, and we describe a novel mechanism of noscapine action through EP2 prostaglandin E2 receptor-mediated activation of PKA in pulmonary fibroblasts.

  11. Epidermis-type lipoxygenase 3 regulates adipocyte differentiation and peroxisome proliferator-activated receptor gamma activity

    DEFF Research Database (Denmark)

    Hallenborg, Philip; Jørgensen, Claus; Petersen, Rasmus K;

    2010-01-01

    The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) is essential for adipogenesis. Although several fatty acids and their derivatives are known to bind and activate PPAR gamma, the nature of the endogenous ligand(s) promoting the early stages of adipocyte differenti...

  12. Second extracellular loop of human glucagon-like peptide-1 receptor (GLP-1R) has a critical role in GLP-1 peptide binding and receptor activation.

    Science.gov (United States)

    Koole, Cassandra; Wootten, Denise; Simms, John; Miller, Laurence J; Christopoulos, Arthur; Sexton, Patrick M

    2012-02-03

    The glucagon-like peptide-1 receptor (GLP-1R) is a therapeutically important family B G protein-coupled receptor (GPCR) that is pleiotropically coupled to multiple signaling effectors and, with actions including regulation of insulin biosynthesis and secretion, is one of the key targets in the management of type II diabetes mellitus. However, there is limited understanding of the role of the receptor core in orthosteric ligand binding and biological activity. To assess involvement of the extracellular loop (ECL) 2 in ligand-receptor interactions and receptor activation, we performed alanine scanning mutagenesis of loop residues and assessed the impact on receptor expression and GLP-1(1-36)-NH(2) or GLP-1(7-36)-NH(2) binding and activation of three physiologically relevant signaling pathways as follows: cAMP formation, intracellular Ca(2+) (Ca(2+)(i)) mobilization, and phosphorylation of extracellular signal-regulated kinases 1 and 2 (pERK1/2). Although antagonist peptide binding was unaltered, almost all mutations affected GLP-1 peptide agonist binding and/or coupling efficacy, indicating an important role in receptor activation. However, mutation of several residues displayed distinct pathway responses with respect to wild type receptor, including Arg-299 and Tyr-305, where mutation significantly enhanced both GLP-1(1-36)-NH(2)- and GLP-1(7-36)-NH(2)-mediated signaling bias for pERK1/2. In addition, mutation of Cys-296, Trp-297, Asn-300, Asn-302, and Leu-307 significantly increased GLP-1(7-36)-NH(2)-mediated signaling bias toward pERK1/2. Of all mutants studied, only mutation of Trp-306 to alanine abolished all biological activity. These data suggest a critical role of ECL2 of the GLP-1R in the activation transition(s) of the receptor and the importance of this region in the determination of both GLP-1 peptide- and pathway-specific effects.

  13. Diabetes and obesity treatment based on dual incretin receptor activation: 'twincretins'

    DEFF Research Database (Denmark)

    Skow, M A; Bergmann, N C; Knop, F K

    2016-01-01

    , whereas GIP seems to affect lipid metabolism. The introduction of selective GLP-1 receptor (GLP-1R) agonists for the treatment of type 2 diabetes and obesity has increased the scientific and clinical interest in incretins. Combining the body weight-lowering and glucose-lowering effects of GLP-1...... with a more potent improvement of β cell function through additional GIP action could potentially offer a more effective treatment of diabetes and obesity, with fewer adverse effects than selective GLP-1R agonists; therefore, new drugs designed to co-activate both the GIP receptor (GIPR) and the GLP-1R...

  14. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors.

    Science.gov (United States)

    Tunaru, Sorin; Althoff, Till F; Nüsing, Rolf M; Diener, Martin; Offermanns, Stefan

    2012-06-01

    Castor oil is one of the oldest drugs. When given orally, it has a laxative effect and induces labor in pregnant females. The effects of castor oil are mediated by ricinoleic acid, a hydroxylated fatty acid released from castor oil by intestinal lipases. Despite the wide-spread use of castor oil in conventional and folk medicine, the molecular mechanism by which ricinoleic acid acts remains unknown. Here we show that the EP(3) prostanoid receptor is specifically activated by ricinoleic acid and that it mediates the pharmacological effects of castor oil. In mice lacking EP(3) receptors, the laxative effect and the uterus contraction induced via ricinoleic acid are absent. Although a conditional deletion of the EP(3) receptor gene in intestinal epithelial cells did not affect castor oil-induced diarrhea, mice lacking EP(3) receptors only in smooth-muscle cells were unresponsive to this drug. Thus, the castor oil metabolite ricinoleic acid activates intestinal and uterine smooth-muscle cells via EP(3) prostanoid receptors. These findings identify the cellular and molecular mechanism underlying the pharmacological effects of castor oil and indicate a role of the EP(3) receptor as a target to induce laxative effects.

  15. Glycine Potentiates AMPA Receptor Function through Metabotropic Activation of GluN2A-containing NMDA Receptors

    Directory of Open Access Journals (Sweden)

    Li-Jun Li

    2016-10-01

    Full Text Available NMDA receptors are Ca2+-permeable ion channels. The activation of NMDA receptors requires agonist glutamate and co-agonist glycine. Recent evidence indicates that NMDA receptor also has metabotropic function. Here we report that in cultured mouse hippocampal neurons, glycine increases AMPA receptor-mediated currents independent of the channel activity of NMDA receptors and the activation of glycine receptors. The potentiation of AMPA receptor function by glycine is antagonized by the inhibition of ERK1/2. In the hippocampal neurons and in the HEK293 cells transfected with different combinations of NMDA receptors, glycine preferentially acts on GluN2A-containing NMDA receptors (GluN2ARs, but not GluN2B-containing NMDA receptors (GluN2BRs, to enhance ERK1/2 phosphorylation independent of the channel activity of GluN2ARs. Without requiring the channel activity of GluN2ARs, glycine increases AMPA receptor-mediated currents through GluN2ARs. Thus, these results reveal a metabotropic function of GluN2ARs in mediating glycine-induced potentiation of AMPA receptor function via ERK1/2 activation.

  16. Glycine Potentiates AMPA Receptor Function through Metabotropic Activation of GluN2A-Containing NMDA Receptors

    Science.gov (United States)

    Li, Li-Jun; Hu, Rong; Lujan, Brendan; Chen, Juan; Zhang, Jian-Jian; Nakano, Yasuko; Cui, Tian-Yuan; Liao, Ming-Xia; Chen, Jin-Cao; Man, Heng-Ye; Feng, Hua; Wan, Qi

    2016-01-01

    NMDA receptors are Ca2+-permeable ion channels. The activation of NMDA receptors requires agonist glutamate and co-agonist glycine. Recent evidence indicates that NMDA receptor also has metabotropic function. Here we report that in cultured mouse hippocampal neurons, glycine increases AMPA receptor-mediated currents independent of the channel activity of NMDA receptors and the activation of glycine receptors. The potentiation of AMPA receptor function by glycine is antagonized by the inhibition of ERK1/2. In the hippocampal neurons and in the HEK293 cells transfected with different combinations of NMDA receptors, glycine preferentially acts on GluN2A-containing NMDA receptors (GluN2ARs), but not GluN2B-containing NMDA receptors (GluN2BRs), to enhance ERK1/2 phosphorylation independent of the channel activity of GluN2ARs. Without requiring the channel activity of GluN2ARs, glycine increases AMPA receptor-mediated currents through GluN2ARs. Thus, these results reveal a metabotropic function of GluN2ARs in mediating glycine-induced potentiation of AMPA receptor function via ERK1/2 activation.

  17. Ghrelin receptor conformational dynamics regulate the transition from a preassembled to an active receptor:Gq complex.

    Science.gov (United States)

    Damian, Marjorie; Mary, Sophie; Maingot, Mathieu; M'Kadmi, Céline; Gagne, Didier; Leyris, Jean-Philippe; Denoyelle, Séverine; Gaibelet, Gérald; Gavara, Laurent; Garcia de Souza Costa, Mauricio; Perahia, David; Trinquet, Eric; Mouillac, Bernard; Galandrin, Ségolène; Galès, Céline; Fehrentz, Jean-Alain; Floquet, Nicolas; Martinez, Jean; Marie, Jacky; Banères, Jean-Louis

    2015-02-03

    How G protein-coupled receptor conformational dynamics control G protein coupling to trigger signaling is a key but still open question. We addressed this question with a model system composed of the purified ghrelin receptor assembled into lipid discs. Combining receptor labeling through genetic incorporation of unnatural amino acids, lanthanide resonance energy transfer, and normal mode analyses, we directly demonstrate the occurrence of two distinct receptor:Gq assemblies with different geometries whose relative populations parallel the activation state of the receptor. The first of these assemblies is a preassembled complex with the receptor in its basal conformation. This complex is specific of Gq and is not observed with Gi. The second one is an active assembly in which the receptor in its active conformation triggers G protein activation. The active complex is present even in the absence of agonist, in a direct relationship with the high constitutive activity of the ghrelin receptor. These data provide direct evidence of a mechanism for ghrelin receptor-mediated Gq signaling in which transition of the receptor from an inactive to an active conformation is accompanied by a rearrangement of a preassembled receptor:G protein complex, ultimately leading to G protein activation and signaling.

  18. Monitoring Affect States during Effortful Problem Solving Activities

    Science.gov (United States)

    D'Mello, Sidney K.; Lehman, Blair; Person, Natalie

    2010-01-01

    We explored the affective states that students experienced during effortful problem solving activities. We conducted a study where 41 students solved difficult analytical reasoning problems from the Law School Admission Test. Students viewed videos of their faces and screen captures and judged their emotions from a set of 14 states (basic…

  19. Activation of a GTP-binding protein and a GTP-binding-protein-coupled receptor kinase (beta-adrenergic-receptor kinase-1) by a muscarinic receptor m2 mutant lacking phosphorylation sites.

    Science.gov (United States)

    Kameyama, K; Haga, K; Haga, T; Moro, O; Sadée, W

    1994-12-01

    A mutant of the human muscarinic acetylcholine receptor m2 subtype (m2 receptor), lacking a large part of the third intracellular loop, was expressed and purified using the baculovirus/insect cell culture system. The mutant was not phosphorylated by beta-adrenergic-receptor kinase, as expected from the previous assignment of phosphorylation sites to the central part of the third intracellular loop. However, the m2 receptor mutant was capable of stimulating beta-adrenergic-receptor-kinase-1-mediated phosphorylation of a glutathione S-transferase fusion protein containing the m2 phosphorylation sites in an agonist-dependent manner. Both mutant and wild-type m2 receptors reconstituted with the guanine-nucleotide-binding regulatory proteins (G protein), G(o) and G(i)2, displayed guanine-nucleotide-sensitive high-affinity agonist binding, as assessed by displacement of [3H]quinuclidinyl-benzilate binding with carbamoylcholine, and both stimulated guanosine 5'-3-O-[35S]thiotriphosphate ([35S]GTP[S]) binding in the presence of carbamoylcholine and GDP. The Ki values of carbamoylcholine effects on [3H]quinuclidinyl-benzilate binding were indistinguishable for the mutant and wild-type m2 receptors. Moreover, the phosphorylation of the wild-type m2 receptor by beta-adrenergic-receptor kinase-1 did not affect m2 interaction with G proteins as assessed by the binding of [3H]quinuclidinyl benzilate or [35S]GTP[S]. These results indicate that (a) the m2 receptor serves both as an activator and as a substrate of beta-adrenergic-receptor kinase, and (b) a large part of the third intracellular loop of the m2 receptor does not contribute to interaction with G proteins and its phosphorylation by beta-adrenergic-receptor kinase does not uncouple the receptor and G proteins in reconstituted lipid vesicles.

  20. Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Kienast, Thorsten; Rapp, Michael [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Siessmeier, Thomas; Buchholz, Hans G.; Schreckenberger, Mathias [University of Mainz, Department of Nuclear Medicine, Mainz (Germany); Wrase, Jana; Heinz, Andreas [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Central Institute of Mental Health, Mannheim (Germany); Braus, Dieter F. [University of Hamburg, Neuroimage Nord, Department of Psychiatry, Hamburg (Germany); Smolka, Michael N.; Mann, Karl [Central Institute of Mental Health, Mannheim (Germany); Roesch, Frank [University of Mainz, Institute of Nuclear Chemistry, Mainz (Germany); Cumming, Paul [PET Center and Center for Functionally Integrative Neuroscience, Aarhus (Denmark); Gruender, Gerhard [Aachen University Medical Center, Department of Psychiatry of the RWTH, Mainz (Germany); Bartenstein, Peter [Ludwig-Maximilians-University, Department of Nuclear Medicine, Munich (Germany)

    2008-06-15

    Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. Subjects were investigated with positron emission tomography and [{sup 18}F]DOPA for measurements of dopamine synthesis capacity and [{sup 18}F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [{sup 18}F]DOPA net influx constant K{sub in}{sup app} /[{sup 18}F]DMFP-binding potential (BP{sub N}D) in the ventral and dorsal striatum. The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas. (orig.)

  1. Allosteric activation mechanism of the cys-loop receptors

    Institute of Scientific and Technical Information of China (English)

    Yong-chang CHANG; Wen WU; Jian-liang ZHANG; Yao HUANG

    2009-01-01

    Binding of a neurotransmitter to its ionotropic receptor opens a distantly located ion channel, a process termed allosteric activation. Here we review recent advances in the molecular mechanism by which the cys-loop receptors are activated with emphasis on the best studied nicotinic acetylcholine receptors (nAChRs). With a combination of affinity labeling, mutagenesis, electrophysiology, kinetic modeling, electron microscopy (EM), and crystal structure analysis, the allosteric activation mechanism is emerging. Specifically, the binding domain and gating domain are interconnected by an allosteric activation network. Agonist binding induces conformational changes, resulting in the rotation of a β sheet of amino-terminal domain and outward movement of loop 2, loop F, and cys-loop, which are coupled to the M2-M3 linker to pull the channel to open. However, there are still some controversies about the movement of the channel-lining domain M2. Nine angstrom resolution EM structure of a nAChR imaged in the open state suggests that channel opening is the result of rotation of the M2 domain. In contrast, recent crystal structures of bacterial homologues of the cys-loop receptor family in apparently open state have implied an M2 tilting model with pore dilation and quaternary twist of the whole pentameric receptor. An elegant study of the nAChR using protonation scanning of M2 domain supports a similar pore dilation activation mechanism with minimal rotation of M2. This remains to be validated with other approaches including high resolution structure determination of the mammalian cys-loop receptors in the open state.

  2. Immunomodulatory effects of endogenous and synthetic peptides activating opioid receptors.

    Science.gov (United States)

    Pomorska, Dorota K; Gach, Katarzyna; Janecka, Anna

    2014-01-01

    The main role of endogenous opioid peptides is the modulation of pain. Opioid peptides exert their analgesic activity by binding to the opioid receptors distributed widely in the central nervous system (CNS). However, opioid receptors are also found on tissues and organs outside the CNS, including the cells of the immune system, indicating that opioids are capable of exerting additional effects in periphery. Morphine, which is a gold standard in the treatment of chronic pain, is well-known for its immunosuppressive effects. Much less is known about the immunomodulatory effects exerted by endogenous (enkephalins, endorphins, dynorphins and endomorphins) and synthetic peptides activating opioid receptors. In this review we tried to summarize opioid peptide-mediated modulation of immune cell functions which can be stimulatory as well as inhibitory.

  3. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation.

    Science.gov (United States)

    Macho, Alberto P; Schwessinger, Benjamin; Ntoukakis, Vardis; Brutus, Alexandre; Segonzac, Cécile; Roy, Sonali; Kadota, Yasuhiro; Oh, Man-Ho; Sklenar, Jan; Derbyshire, Paul; Lozano-Durán, Rosa; Malinovsky, Frederikke Gro; Monaghan, Jacqueline; Menke, Frank L; Huber, Steven C; He, Sheng Yang; Zipfel, Cyril

    2014-03-28

    Innate immunity relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs) located on the host cell's surface. Many plant PRRs are kinases. Here, we report that the Arabidopsis receptor kinase EF-TU RECEPTOR (EFR), which perceives the elf18 peptide derived from bacterial elongation factor Tu, is activated upon ligand binding by phosphorylation on its tyrosine residues. Phosphorylation of a single tyrosine residue, Y836, is required for activation of EFR and downstream immunity to the phytopathogenic bacterium Pseudomonas syringae. A tyrosine phosphatase, HopAO1, secreted by P. syringae, reduces EFR phosphorylation and prevents subsequent immune responses. Thus, host and pathogen compete to take control of PRR tyrosine phosphorylation used to initiate antibacterial immunity.

  4. Cannabinoid receptor 1 signalling dampens activity and mitochondrial transport in networks of enteric neurones.

    Science.gov (United States)

    Boesmans, W; Ameloot, K; van den Abbeel, V; Tack, J; Vanden Berghe, P

    2009-09-01

    Cannabinoid (CB) receptors are expressed in the enteric nervous system (ENS) and CB(1) receptor activity slows down motility and delays gastric emptying. This receptor system has become an important target for GI-related drug development such as in obesity treatment. The aim of the study was to investigate how CB(1) ligands and antagonists affect ongoing activity in enteric neurone networks, modulate synaptic vesicle cycling and influence mitochondrial transport in nerve processes. Primary cultures of guinea-pig myenteric neurones were loaded with different fluorescent markers: Fluo-4 to measure network activity, FM1-43 to image synaptic vesicles and Mitotracker green to label mitochondria. Synaptic vesicle cluster density was assessed by immunohistochemistry and expression of CB(1) receptors was confirmed by RT-PCR. Spontaneous network activity, displayed by both excitatory and inhibitory neurones, was significantly increased by CB(1) receptor antagonists (AM-251 and SR141716), abolished by CB(1) activation (methanandamide, mAEA) and reduced by two different inhibitors (arachidonylamide serotonin, AA-5HT and URB597) of fatty acid amide hydrolase. Antagonists reduced the number of synaptic vesicles that were recycled during an electrical stimulus. CB(1) agonists (mAEA and WIN55,212) reduced and antagonists enhanced the fraction of transported mitochondria in enteric nerve fibres. We found immunohistochemical evidence for an enhancement of synaptophysin-positive release sites with SR141716, while WIN55,212 caused a reduction. The opposite effects of agonists and antagonists suggest that enteric nerve signalling is under the permanent control of CB(1) receptor activity. Using inhibitors of the endocannabinoid degrading enzyme, we were able to show there is endogenous production of a CB ligand in the ENS.

  5. Antisense RNA that Affects Rhodopseudomonas palustris Quorum-Sensing Signal Receptor Expression

    Science.gov (United States)

    2012-01-01

    terminal region of the Vibrio fischeri LuxR pro- tein contains an inducer-independent lux gene activating domain. Proc Natl Acad Sci USA 88:11115...synthesis requires exogenous p-coumarate (1). The R. palustris signal synthesis gene , rpaI, codes for a member of the large LuxI family of AHL synthases, and...the adjacent signal receptor gene , rpaR, codes for a member of the LuxR family of transcription factors. Although rpaI and rpaR are not cotran

  6. Aryl Hydrocarbon Receptor Activation by TCDD Reduces Inflammation Associated with Crohn's Disease

    OpenAIRE

    Benson, Jenna M.; Shepherd, David M.

    2010-01-01

    Crohn's disease results from a combination of genetic and environmental factors that trigger an inappropriate immune response to commensal gut bacteria. The aryl hydrocarbon receptor (AhR) is well known for its involvement in the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an environmental contaminant that affects people primarily through the diet. Recently, TCDD was shown to suppress immune responses by generating regulatory T cells (Tregs). We hypothesized that AhR activation da...

  7. Estrogen Receptor β Agonists Differentially Affect the Growth of Human Melanoma Cell Lines.

    Directory of Open Access Journals (Sweden)

    Monica Marzagalli

    Full Text Available Cutaneous melanoma is an aggressive malignancy; its incidence is increasing worldwide and its prognosis remains poor. Clinical observations indicate that estrogen receptor β (ERβ is expressed in melanoma tissues and its expression decreases with tumor progression, suggesting its tumor suppressive function. These experiments were performed to investigate the effects of ERβ activation on melanoma cell growth.Protein expression was analyzed by Western blot and immunofluorescence assays. Cell proliferation was assessed by counting the cells by hemocytometer. ERβ transcriptional activity was evaluated by gene reporter assay. Global DNA methylation was analyzed by restriction enzyme assay and ERβ isoforms were identified by qRT-PCR. We demonstrated that ERβ is expressed in a panel of human melanoma cell lines (BLM, WM115, A375, WM1552. In BLM (NRAS-mutant cells, ERβ agonists significantly and specifically inhibited cell proliferation. ERβ activation triggered its cytoplasmic-to-nuclear translocation and transcriptional activity. Moreover, the antiproliferative activity of ERβ agonists was associated with an altered expression of G1-S transition-related proteins. In these cells, global DNA was found to be hypomethylated when compared to normal melanocytes; this DNA hypomethylation status was reverted by ERβ activation. ERβ agonists also decreased the proliferation of WM115 (BRAF V600D-mutant cells, while they failed to reduce the growth of A375 and WM1552 (BRAF V600E-mutant cells. Finally, we could observe that ERβ isoforms are expressed at different levels in the various cell lines. Specific oncogenic mutations or differential expression of receptor isoforms might be responsible for the different responses of cell lines to ERβ agonists.Our results demonstrate that ERβ is expressed in melanoma cell lines and that ERβ agonists differentially regulate the proliferation of these cells. These data confirm the notion that melanoma is a

  8. Functional Selectivity and Antidepressant Activity of Serotonin 1A Receptor Ligands

    Directory of Open Access Journals (Sweden)

    Zdzisław Chilmonczyk

    2015-08-01

    Full Text Available Serotonin (5-HT is a monoamine neurotransmitter that plays an important role in physiological functions. 5-HT has been implicated in sleep, feeding, sexual behavior, temperature regulation, pain, and cognition as well as in pathological states including disorders connected to mood, anxiety, psychosis and pain. 5-HT1A receptors have for a long time been considered as an interesting target for the action of antidepressant drugs. It was postulated that postsynaptic 5-HT1A agonists could form a new class of antidepressant drugs, and mixed 5-HT1A receptor ligands/serotonin transporter (SERT inhibitors seem to possess an interesting pharmacological profile. It should, however, be noted that 5-HT1A receptors can activate several different biochemical pathways and signal through both G protein-dependent and G protein-independent pathways. The variables that affect the multiplicity of 5-HT1A receptor signaling pathways would thus result from the summation of effects specific to the host cell milieu. Moreover, receptor trafficking appears different at pre- and postsynaptic sites. It should also be noted that the 5-HT1A receptor cooperates with other signal transduction systems (like the 5-HT1B or 5-HT2A/2B/2C receptors, the GABAergic and the glutaminergic systems, which also contribute to its antidepressant and/or anxiolytic activity. Thus identifying brain specific molecular targets for 5-HT1A receptor ligands may result in a better targeting, raising a hope for more effective medicines for various pathologies.

  9. Ah receptor agonist activity in frequently consumed food items

    NARCIS (Netherlands)

    Waard, de W.J.; Aarts, J.M.M.J.G.; Peijnenburg, A.A.C.M.; Kok, de T.M.C.M.; Schooten, van F.J.; Hoogenboom, L.A.P.

    2008-01-01

    The aryl hydrocarbon receptor (AhR) receives much attention for its role in the toxicity of dioxins and dioxin-like polychlorinated biphenyls. However, many other compounds have also been reported to bind and activate AhR, of which natural food components are of special interest from a human health

  10. The cardiovascular effects of peroxisome proliferator-activated receptor agonists.

    Science.gov (United States)

    Friedland, Sayuri N; Leong, Aaron; Filion, Kristian B; Genest, Jacques; Lega, Iliana C; Mottillo, Salvatore; Poirier, Paul; Reoch, Jennifer; Eisenberg, Mark J

    2012-02-01

    Although peroxisome proliferator-activated receptor agonists are prescribed to improve cardiovascular risk factors, their cardiovascular safety is controversial. We therefore reviewed the literature to identify landmark randomized controlled trials evaluating the effect of peroxisome proliferator-activated receptor gamma agonists (pioglitazone and rosiglitazone), alpha agonists (fenofibrate and gemfibrozil), and pan agonists (bezafibrate, muraglitazar, ragaglitazar, tesaglitazar, and aleglitazar) on cardiovascular outcomes. Pioglitazone may modestly reduce cardiovascular events but also may increase the risk of bladder cancer. Rosiglitazone increases the risk of myocardial infarction and has been withdrawn in European and restricted in the United States. Fibrates improve cardiovascular outcomes only in select subgroups: fenofibrate in diabetic patients with metabolic syndrome, gemfibrozil in patients with dyslipidemia, and bezafibrate in patients with diabetes or metabolic syndrome. The cardiovascular safety of the new pan agonist aleglitazar, currently in phase II trials, remains to be determined. The heterogenous effects of peroxisome proliferator-activated receptor agonists to date highlight the importance of postmarketing surveillance. The critical question of why peroxisome proliferator-activated receptor agonists seem to improve cardiovascular risk factors without significantly improving cardiovascular outcomes requires further investigation.

  11. Asymmetric frontal cortical activity and negative affective responses to ostracism.

    Science.gov (United States)

    Peterson, Carly K; Gravens, Laura C; Harmon-Jones, Eddie

    2011-06-01

    Ostracism arouses negative affect. However, little is known about variables that influence the intensity of these negative affective responses. Two studies fill this void by incorporating work on approach- and withdrawal-related emotional states and their associated cortical activations. Study 1 found that following ostracism anger related directly to relative left frontal cortical activation. Study 2 used unilateral hand contractions to manipulate frontal cortical activity prior to an ostracizing event. Right-hand contractions, compared to left-hand contractions, caused greater relative left frontal cortical activation during the hand contractions as well as ostracism. Also, right-hand contractions caused more self-reported anger in response to being ostracized. Within-condition correlations revealed patterns of associations between ostracism-induced frontal asymmetry and emotive responses to ostracism consistent with Study 1. Taken together, these results suggest that asymmetrical frontal cortical activity is related to angry responses to ostracism, with greater relative left frontal cortical activity being associated with increased anger.

  12. A PTK7/Ror2 Co-Receptor Complex Affects Xenopus Neural Crest Migration.

    Directory of Open Access Journals (Sweden)

    Martina Podleschny

    Full Text Available Neural crest cells are a highly migratory pluripotent cell population that generates a wide array of different cell types and failure in their migration can result in severe birth defects and malformation syndromes. Neural crest migration is controlled by various means including chemotaxis, repellent guidance cues and cell-cell interaction. Non-canonical Wnt PCP (planar cell polarity signaling has previously been shown to control cell-contact mediated neural crest cell guidance. PTK7 (protein tyrosine kinase 7 is a transmembrane pseudokinase and a known regulator of Wnt/PCP signaling, which is expressed in Xenopus neural crest cells and required for their migration. PTK7 functions as a Wnt co-receptor; however, it remains unclear by which means PTK7 affects neural crest migration. Expressing fluorescently labeled proteins in Xenopus neural crest cells we find that PTK7 co-localizes with the Ror2 Wnt-receptor. Further, co-immunoprecipitation experiments demonstrate that PTK7 interacts with Ror2. The PTK7/Ror2 interaction is likely relevant for neural crest migration, because Ror2 expression can rescue the PTK7 loss of function migration defect. Live cell imaging of explanted neural crest cells shows that PTK7 loss of function affects the formation of cell protrusions as well as cell motility. Co-expression of Ror2 can rescue these defects. In vivo analysis demonstrates that a kinase dead Ror2 mutant cannot rescue PTK7 loss of function. Thus, our data suggest that Ror2 can substitute for PTK7 and that the signaling function of its kinase domain is required for this effect.

  13. Identification of prostaglandin E2 receptor subtype 2 as a receptor activated by OxPAPC.

    Science.gov (United States)

    Li, Rongsong; Mouillesseaux, Kevin P; Montoya, Dennis; Cruz, Daniel; Gharavi, Navid; Dun, Martin; Koroniak, Lukasz; Berliner, Judith A

    2006-03-17

    Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OxPAPC), which has been shown to accumulate in atherosclerotic lesions and other sites of chronic inflammation, activates endothelial cells (EC) to bind monocytes by activation of endothelial beta1 integrin and subsequent deposition of fibronectin on the apical surface. Our previous studies suggest this function of OxPAPC is mediated via a Gs protein-coupled receptor (GPCR). PEIPC (1-palmitoyl-2-epoxyisoprostane E2-sn-glycero-3-phosphorylcholine) is the most active lipid in OxPAPC that activates this pathway. We screened a number of candidate GPCRs for their interaction with OxPAPC and PEIPC, using a reporter gene assay; we identified prostaglandin E2 receptor EP2 and prostaglandin D2 receptor DP as responsive to OxPAPC. We focused on EP2, which is expressed in ECs, monocytes, and macrophages. OxPAPC component PEIPC, but not POVPC, activated EP2 with an EC50 of 108.6 nmol/L. OxPAPC and PEIPC were also able to compete with PGE2 for binding to EP2 in a ligand-binding assay. The EP2 specific agonist butaprost was shown to mimic the effect of OxPAPC on the activation of beta1 integrin and the stimulation of monocyte binding to endothelial cells. Butaprost also mimicked the effect of OxPAPC on the regulation of tumor necrosis factor-alpha and interleukin-10 in monocyte-derived cells. EP2 antagonist AH6809 blocked the activation of EP2 by OxPAPC in HEK293 cells and blocked the interleukin-10 response to PEIPC in monocytic THP-1 cells. These results suggest that EP2 functions as a receptor for OxPAPC and PEIPC, either as the phospholipid ester or the released fatty acid, in both endothelial cells and macrophages.

  14. How does the anthropogenic activity affect the spring discharge?

    Science.gov (United States)

    Hao, Yonghong; Zhang, Juan; Wang, Jiaojiao; Li, Ruifang; Hao, Pengmei; Zhan, Hongbin

    2016-09-01

    Karst hydrological process has largely been altered by climate change and human activity. In many places throughout the world, human activity (e.g. groundwater pumping and dewatering from mining) has intensified and surpassed climate change, where human activity becomes the primary factor that affects groundwater system. But it is still largely unclear how the human activity affects spring discharge in magnitude and periodicity. This study investigates the effects of anthropogenic activity on spring discharge, using the Xin'an Springs of China as an example. The Xin'an Spring discharge were divided into two time periods: the pre-development period from 1956 to 1971 and the post-development period from 1972 to 2013. We confirm the dividing time (i.e. 1971) of these two periods using the Wilcoxon rank-sum test. Then the wavelet transform and wavelet coherence were used to analyze the karst hydrological processes for the two periods respectively. We analyze the correlations of precipitation and the Xin'an spring discharge with the monsoons including the Indian Summer Monsoon (ISM) and the West North Pacific Monsoon (WNPM) and the climate teleconnections including El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), respectively. The results indicated that the spring discharge was attenuated about 19.63% under the influence of human activity in the Xin'an Springs basin. However, human activity did not alter the size of the resonance frequencies between the spring discharge and the monsoons. In contrast, it reinforced the periodicities of the monsoons-driven spring discharge. It suggested that human has adapted to the major climate periodicities, and human activity had the same rhyme with the primary climate periodicity. In return, human activity enhances the correlation between the monsoons and the spring discharge.

  15. Rifaximin is a gut-specific human pregnane X receptor activator.

    Science.gov (United States)

    Ma, Xiaochao; Shah, Yatrik M; Guo, Grace L; Wang, Ting; Krausz, Kristopher W; Idle, Jeffrey R; Gonzalez, Frank J

    2007-07-01

    Rifaximin, a rifamycin analog approved for the treatment of travelers' diarrhea, is also beneficial in the treatment of multiple chronic gastrointestinal disorders. However, the mechanisms contributing to the effects of rifaximin on chronic gastrointestinal disorders are not fully understood. In the current study, rifaximin was investigated for its role in activation of the pregnane X receptor (PXR), a nuclear receptor that regulates genes involved in xenobiotic and limited endobiotic deposition and detoxication. PXR-humanized (hPXR), Pxr-null, and wild-type mice were treated orally with rifaximin, and rifampicin, a well characterized human PXR ligand. Rifaximin was highly concentrated in the intestinal tract compared with rifampicin. Rifaximin treatment resulted in significant induction of PXR target genes in the intestine of hPXR mice, but not in wild-type and Pxr-null mice. However, rifaximin treatment demonstrated no significant effect on hepatic PXR target genes in wild-type, Pxr-null, and hPXR mice. Consistent with the in vivo data, cell-based reporter gene assay revealed rifaximin-mediated activation of human PXR, but not the other xenobiotic nuclear receptors constitutive androstane receptor, peroxisome proliferator-activated receptor (PPAR)alpha, PPARgamma, and farnesoid X receptor. Pretreatment with rifaximin did not affect the pharmacokinetics of the CYP3A substrate midazolam, but it increased the C(max) and decreased T(max) of 1'-hydroxymidazolam. Collectively, the current study identified rifaximin as a gut-specific human PXR ligand, and it provided further evidence for the utility of hPXR mice as a critical tool for the study of human PXR activators. Further human studies are suggested to assess the potential role of rifaximin-mediated gut PXR activation in therapeutics of chronic gastrointestinal disorders.

  16. Antiseizure Activity of Midazolam in Mice Lacking δ-Subunit Extrasynaptic GABA(A) Receptors.

    Science.gov (United States)

    Reddy, Sandesh D; Younus, Iyan; Clossen, Bryan L; Reddy, Doodipala Samba

    2015-06-01

    Midazolam is a benzodiazepine anticonvulsant with rapid onset and short duration of action. Midazolam is the current drug of choice for acute seizures and status epilepticus, including those caused by organophosphate nerve agents. The antiseizure activity of midazolam is thought to result from its allosteric potentiation of synaptic GABA(A) receptors in the brain. However, there are indications that benzodiazepines promote neurosteroid synthesis via the 18-kDa cholesterol transporter protein (TSPO). Therefore, we investigated the role of neurosteroids and their extrasynaptic GABA(A) receptor targets in the antiseizure activity of midazolam. Here, we used δ-subunit knockout (DKO) mice bearing a targeted deletion of the extrasynaptic receptors to investigate the contribution of the extrasynaptic receptors to the antiseizure activity of midazolam using the 6-Hz and hippocampus kindling seizure models. In both models, midazolam produced rapid and dose-dependent protection against seizures (ED50, 0.4 mg/kg). Moreover, the antiseizure potency of midazolam was undiminished in DKO mice compared with control mice. Pretreatment with PK11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide], a TSPO blocker, or finasteride, a 5α-reductase neurosteroid inhibitor, did not affect the antiseizure effect of midazolam. The antiseizure activity of midazolam was significantly reversed by pretreatment with flumazenil, a benzodiazepine antagonist. Plasma and brain levels of the neurosteroid allopregnanolone were not significantly greater in midazolam-treated animals. These studies therefore provide strong evidence that neurosteroids and extrasynaptic GABA(A) receptors are not involved in the antiseizure activity of midazolam, which mainly occurs through synaptic GABA(A) receptors via direct binding to benzodiazepine sites. This study reaffirms midazolam's use for controlling acute seizures and status epilepticus.

  17. Neurohumoral activation in heart failure: the role of adrenergic receptors

    OpenAIRE

    Patricia C. Brum; Rolim, Natale P. L.; BACURAU, Aline V. N.; Alessandra Medeiros

    2006-01-01

    Heart failure (HF) is a common endpoint for many forms of cardiovascular disease and a significant cause of morbidity and mortality. The development of end-stage HF often involves an initial insult to the myocardium that reduces cardiac output and leads to a compensatory increase in sympathetic nervous system activity. Acutely, the sympathetic hyperactivity through the activation of beta-adrenergic receptors increases heart rate and cardiac contractility, which compensate for decreased cardia...

  18. Facilitation of neocortical presynaptic terminal development by NMDA receptor activation

    OpenAIRE

    2012-01-01

    Abstract Background Neocortical circuits are established through the formation of synapses between cortical neurons, but the molecular mechanisms of synapse formation are only beginning to be understood. The mechanisms that control synaptic vesicle (SV) and active zone (AZ) protein assembly at developing presynaptic terminals have not yet been defined. Similarly, the role of glutamate receptor activation in control of presynaptic development remains unclear. Results Here, we use confocal imag...

  19. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Shoko, E-mail: satosho@rs.tus.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp [Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Yonago 683-8503 (Japan); Tohkin, Masahiro, E-mail: tohkin@phar.nagoya-cu.ac.jp [Department of Medical Safety Science, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya 267-8603 (Japan); Gonzalez, Frank J., E-mail: gonzalef@mail.nih.gov [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Komai, Michio, E-mail: mkomai@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan)

    2013-11-15

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.

  20. Influence of phasic and tonic dopamine release on receptor activation

    DEFF Research Database (Denmark)

    Dreyer, Jakob Kristoffer Kisbye; Herrik, Kjartan F; Berg, Rune W

    2010-01-01

    Tonic and phasic dopamine release is implicated in learning, motivation, and motor functions. However, the relationship between spike patterns in dopaminergic neurons, the extracellular concentration of dopamine, and activation of dopamine receptors remains unresolved. In the present study, we...... develop a computational model of dopamine signaling that give insight into the relationship between the dynamics of release and occupancy of D(1) and D(2) receptors. The model is derived from first principles using experimental data. It has no free parameters and offers unbiased estimation...

  1. ICAM-5 affects spine maturation by regulation of NMDA receptor binding to α-actinin

    Directory of Open Access Journals (Sweden)

    Lin Ning

    2015-01-01

    Full Text Available ICAM-5 is a negative regulator of dendritic spine maturation and facilitates the formation of filopodia. Its absence results in improved memory functions, but the mechanisms have remained poorly understood. Activation of NMDA receptors induces ICAM-5 ectodomain cleavage through a matrix metalloproteinase (MMP-dependent pathway, which promotes spine maturation and synapse formation. Here, we report a novel, ICAM-5-dependent mechanism underlying spine maturation by regulating the dynamics and synaptic distribution of α-actinin. We found that GluN1 and ICAM-5 partially compete for the binding to α-actinin; deletion of the cytoplasmic tail of ICAM-5 or ablation of the gene resulted in increased association of GluN1 with α-actinin, whereas internalization of ICAM-5 peptide perturbed the GluN1/α-actinin interaction. NMDA treatment decreased α-actinin binding to ICAM-5, and increased the binding to GluN1. Proper synaptic distribution of α-actinin requires the ICAM-5 cytoplasmic domain, without which α-actinin tended to accumulate in filopodia, leading to F-actin reorganization. The results indicate that ICAM-5 retards spine maturation by preventing reorganization of the actin cytoskeleton, but NMDA receptor activation is sufficient to relieve the brake and promote the maturation of spines.

  2. An improved ivermectin-activated chloride channel receptor for inhibiting electrical activity in defined neuronal populations

    DEFF Research Database (Denmark)

    Lynagh, Timothy Peter; Lynch, Joseph W

    2010-01-01

    for surgically implanted stimulus delivery methods and their use of nonhuman receptors. A third silencing method, an invertebrate glutamate-gated chloride channel receptor (GluClR) activated by ivermectin, solves the stimulus delivery problem as ivermectin is a safe, well tolerated drug that reaches the brain...

  3. Inbreeding affects locomotor activity in Drosophila melanogaster at different ages

    DEFF Research Database (Denmark)

    Manenti, Tommaso; Pertoldi, Cino; Nasiri Moghadam, Neda

    2015-01-01

    The ability to move is essential for many behavioural traits closely related to fitness. Here we studied the effect of inbreeding on locomotor activity (LA) of Drosophila melanogaster at different ages under both dark and light regimes. We expected to find a decreased LA in inbred lines compared...... LA than control lines. Moreover, age per se did not affect LA neither in control nor in inbred lines, while we found a strong line by age interaction between inbred lines. Interestingly, inbreeding changed the daily activity pattern of the flies: these patterns were consistent across all control...

  4. M1 muscarinic acetylcholine receptor agonism alters sleep without affecting memory consolidation.

    Science.gov (United States)

    Nissen, Christoph; Power, Ann E; Nofzinger, Eric A; Feige, Bernd; Voderholzer, Ulrich; Kloepfer, Corinna; Waldheim, Bernhard; Radosa, Marc-Philipp; Berger, Mathias; Riemann, Dieter

    2006-11-01

    Preclinical studies have implicated cholinergic neurotransmission, specifically M1 muscarinic acetylcholine receptor (mAChR) activation, in sleep-associated memory consolidation. In the present study, we investigated the effects of administering the direct M1 mAChR agonist RS-86 on pre-post sleep memory consolidation. Twenty healthy human participants were tested in a declarative word-list task and a procedural mirror-tracing task. RS-86 significantly reduced rapid eye movement (REM) sleep latency and slow wave sleep (SWS) duration in comparison with placebo. Presleep acquisition and postsleep recall rates were within the expected ranges. However, recall rates in both tasks were almost identical for the RS-86 and placebo conditions. These results indicate that selective M1 mAChR activation in healthy humans has no clinically relevant effect on pre-post sleep consolidation of declarative or procedural memories at a dose that reduces REM sleep latency and SWS duration.

  5. Catechol-o-methyltransferase expression and 2-methoxyestradiol affect microtubule dynamics and modify steroid receptor signaling in leiomyoma cells.

    Directory of Open Access Journals (Sweden)

    Salama A Salama

    Full Text Available CONTEXT: Development of optimal medicinal treatments of uterine leiomyomas represents a significant challenge. 2-Methoxyestradiol (2ME is an endogenous estrogen metabolite formed by sequential action of CYP450s and catechol-O-methyltransferase (COMT. Our previous study demonstrated that 2ME is a potent antiproliferative, proapoptotic, antiangiogenic, and collagen synthesis inhibitor in human leiomyomas cells (huLM. OBJECTIVES: Our objectives were to investigate whether COMT expression, by the virtue of 2ME formation, affects the growth of huLM, and to explore the cellular and molecular mechanisms whereby COMT expression or treatment with 2ME affect these cells. RESULTS: Our data demonstrated that E(2-induced proliferation was less pronounced in cells over-expressing COMT or treated with 2ME (500 nM. This effect on cell proliferation was associated with microtubules stabilization and diminution of estrogen receptor alpha (ERalpha and progesterone receptor (PR transcriptional activities, due to shifts in their subcellular localization and sequestration in the cytoplasm. In addition, COMT over expression or treatment with 2ME reduced the expression of hypoxia-inducible factor -1alpha (HIF-1 alpha and the basal level as well as TNF-alpha-induced aromatase (CYP19 expression. CONCLUSIONS: COMT over expression or treatment with 2ME stabilize microtubules, ameliorates E(2-induced proliferation, inhibits ERalpha and PR signaling, and reduces HIF-1 alpha and CYP19 expression in human uterine leiomyoma cells. Thus, microtubules are a candidate target for treatment of uterine leiomyomas. In addition, the naturally occurring microtubule-targeting agent 2ME represents a potential new therapeutic for uterine leiomyomas.

  6. Charge and geometry of residues in the loop 2 β hairpin differentially affect agonist and ethanol sensitivity in glycine receptors.

    Science.gov (United States)

    Perkins, Daya I; Trudell, James R; Asatryan, Liana; Davies, Daryl L; Alkana, Ronald L

    2012-05-01

    Recent studies highlighted the importance of loop 2 of α1 glycine receptors (GlyRs) in the propagation of ligand-binding energy to the channel gate. Mutations that changed polarity at position 52 in the β hairpin of loop 2 significantly affected sensitivity to ethanol. The present study extends the investigation to charged residues. We found that substituting alanine with the negative glutamate at position 52 (A52E) significantly left-shifted the glycine concentration response curve and increased sensitivity to ethanol, whereas the negative aspartate substitution (A52D) significantly right-shifted the glycine EC₅₀ but did not affect ethanol sensitivity. It is noteworthy that the uncharged glutamine at position 52 (A52Q) caused only a small right shift of the glycine EC₅₀ while increasing ethanol sensitivity as much as A52E. In contrast, the shorter uncharged asparagine (A52N) caused the greatest right shift of glycine EC₅₀ and reduced ethanol sensitivity to half of wild type. Collectively, these findings suggest that charge interactions determined by the specific geometry of the amino acid at position 52 (e.g., the 1-Å chain length difference between aspartate and glutamate) play differential roles in receptor sensitivity to agonist and ethanol. We interpret these results in terms of a new homology model of GlyR based on a prokaryotic ion channel and propose that these mutations form salt bridges to residues across the β hairpin (A52E-R59 and A52N-D57). We hypothesize that these electrostatic interactions distort loop 2, thereby changing agonist activation and ethanol modulation. This knowledge will help to define the key physical-chemical parameters that cause the actions of ethanol in GlyRs.

  7. Activation of D4 dopamine receptor decreases angiotensin II type 1 receptor expression in rat renal proximal tubule cells.

    Science.gov (United States)

    Chen, Ken; Deng, Kun; Wang, Xiaoyan; Wang, Zhen; Zheng, Shuo; Ren, Hongmei; He, Duofen; Han, Yu; Asico, Laureano D; Jose, Pedro A; Zeng, Chunyu

    2015-01-01

    The dopaminergic and renin-angiotensin systems interact to regulate blood pressure. Disruption of the D4 dopamine receptor gene in mice produces hypertension that is associated with increased renal angiotensin type 1 (AT1) receptor expression. We hypothesize that the D4 receptor can inhibit AT1 receptor expression and function in renal proximal tubule cells from Wistar-Kyoto (WKY) rats, but the D4 receptor regulation of AT1 receptor is aberrant in renal proximal tubule cells from spontaneously hypertensive rats (SHRs). The D4 receptor agonist, PD168077, decreased AT1 receptor protein expression in a time- and concentration-dependent manner in WKY cells. By contrast, in SHR cells, PD168077 increased AT1 receptor protein expression. The inhibitory effect of D4 receptor on AT1 receptor expression in WKY cells was blocked by a calcium channel blocker, nicardipine, or calcium-free medium, indicating that calcium is involved in the D4 receptor-mediated signaling pathway. Angiotensin II increased Na(+)-K(+) ATPase activity in WKY cells. Pretreatment with PD168077 decreased the stimulatory effect of angiotensin II on Na(+)-K(+) ATPase activity in WKY cells. In SHR cells, the inhibitory effect of D4 receptor on angiotensin II-mediated stimulation of Na(+)-K(+) ATPase activity was aberrant; pretreatment with PD168077 augmented the stimulatory effect of AT1 receptor on Na(+)-K(+) ATPase activity in SHR cells. This was confirmed in vivo; pretreatment with PD128077 for 1 week augmented the antihypertensive and natriuretic effect of losartan in SHRs but not in WKY rats. We suggest that an aberrant interaction between D4 and AT1 receptors may play a role in the abnormal regulation of sodium excretion in hypertension.

  8. Peroxisome proliferator-activated receptor alpha target genes.

    Science.gov (United States)

    Rakhshandehroo, Maryam; Knoch, Bianca; Müller, Michael; Kersten, Sander

    2010-01-01

    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.

  9. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    Directory of Open Access Journals (Sweden)

    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.

  10. Glycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration

    Directory of Open Access Journals (Sweden)

    Ariel Avila

    2013-08-01

    Full Text Available Glycine receptors (GlyRs are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.

  11. Dynamic modulation of inflammatory pain-related affective and sensory symptoms by optical control of amygdala metabotropic glutamate receptor 4.

    Science.gov (United States)

    Zussy, C; Gómez-Santacana, X; Rovira, X; De Bundel, D; Ferrazzo, S; Bosch, D; Asede, D; Malhaire, F; Acher, F; Giraldo, J; Valjent, E; Ehrlich, I; Ferraguti, F; Pin, J-P; Llebaria, A; Goudet, C

    2016-12-20

    Contrary to acute pain, chronic pain does not serve as a warning signal and must be considered as a disease per se. This pathology presents a sensory and psychological dimension at the origin of affective and cognitive disorders. Being largely refractory to current pharmacotherapies, identification of endogenous systems involved in persistent and chronic pain is crucial. The amygdala is a key brain region linking pain sensation with negative emotions. Here, we show that activation of a specific intrinsic neuromodulatory system within the amygdala associated with type 4 metabotropic glutamate receptors (mGlu4) abolishes sensory and affective symptoms of persistent pain such as hypersensitivity to pain, anxiety- and depression-related behaviors, and fear extinction impairment. Interestingly, neuroanatomical and synaptic analysis of the amygdala circuitry suggests that the effects of mGlu4 activation occur outside the central nucleus via modulation of multisensory thalamic inputs to lateral amygdala principal neurons and dorso-medial intercalated cells. Furthermore, we developed optogluram, a small diffusible photoswitchable positive allosteric modulator of mGlu4. This ligand allows the control of endogenous mGlu4 activity with light. Using this photopharmacological approach, we rapidly and reversibly inhibited behavioral symptoms associated with persistent pain through optical control of optogluram in the amygdala of freely behaving animals. Altogether, our data identify amygdala mGlu4 signaling as a mechanism that bypasses central sensitization processes to dynamically modulate persistent pain symptoms. Our findings help to define novel and more precise therapeutic interventions for chronic pain, and exemplify the potential of optopharmacology to study the dynamic activity of endogenous neuromodulatory mechanisms in vivo.Molecular Psychiatry advance online publication, 20 December 2016; doi:10.1038/mp.2016.223.

  12. Active house: A contemporary housing model for flood affected population

    Directory of Open Access Journals (Sweden)

    Stratimirović Tatjana

    2015-01-01

    Full Text Available The effectiveness of architectural knowledge in the struggle for a better future can be seen in the attitude that a good design or a good architectural solution, does not belong solely to the privileged ones as an improvement of the basic requirements, rather quite the opposite, that it is created as a response to a need. The goal of physical and emotional wellbeing, combined with a long term strategy for reducing the negative impact of the built environment by converting it into a positive influence upon the natural ecosystem, brings together and advances bioclimatic principles, architectural design and sustainable construction in the contemporary housing model dubbed the Active House. The Active House Workshop was held, as part of a wider student initiative New Housing Models for Flood Affected Population, at the University of Belgrade - Faculty of Architecture. The purpose of the campaign was to provide help to flood affected communities and assistance in efforts for repairing buildings in Serbia, hit by the severe floods of May 2014. Students came up with nine design solutions for small family homes, which incorporate the principles of Active House into existing construction techniques. In an architectural context, when concerning repair work after flooding, the need to consider problems related to contemporary living conditions through the ‘active’ category is seen in a new understanding of nature which allows the replacement of a passive restoration model, with an active models for designing in interaction with the environment.

  13. How does stress affect human being—a molecular dynamic simulation study on cortisol and its glucocorticoid receptor

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    Dan Zhang

    2017-03-01

    Full Text Available Stress can be either positive or negative to human beings. Under stressful conditions, the mental and physical conditions of human can be affected. There exists certain relation between stress and illness. The cortisol and other glucocorticoids bind to the same receptor, which is called glucocorticoid receptor. Some evidences indicated that cortisol molecule binding to its glucocorticoid receptor was necessary for the stress response. Up to now, the structure–function relationships between cortisol molecule and its glucocorticoid receptor have not been deliberated from the atomic-level. In order to get a detailed understanding of the structure–function relationships between the cortisol molecule and glucocorticoids receptor, we have carried out molecular dynamic (MD simulations on glucocorticoid receptor (Apo system and cortisol with its glucocorticoid receptor complex (HCY system. On the basis of molecular dynamic simulations, a couple of key residues were identified, which were crucial for the binding of cortisol molecule. The results of binding free energy calculations are in good agreement with the experiment data. Our research gives clear insights from atomic-level into the structural–functional aspects of cortisol molecule and its glucocorticoid receptor, and also provides valuable information for the design of drug which can treat stress related illnesses.

  14. Altered promoter recycling rates contribute to dominant-negative activity of human peroxisome proliferator-activated receptor-gamma mutations associated with diabetes.

    Science.gov (United States)

    Li, Gang; Leff, Todd

    2007-04-01

    The transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma) plays an important role in regulating lipid and glucose metabolism and improves insulin sensitivity in diabetic patients when activated by thiazolidinedione drugs. Several loss-of-function mutations in PPARgamma have been identified that cause lipodystrophy and diabetes in humans. Because affected individuals are heterozygotes and have one normal PPARgamma allele, it is of interest to know whether these mutations act in a dominant-negative fashion to inhibit the activity of the wild-type (WT) receptor. Here we compare the molecular phenotypes of two previously identified PPARgamma mutations: P467L, reported to be dominant negative; and F388L, reported to be devoid of dominant-negative activity. We developed a competitive chromatin immunoprecipitation assay to measure the relative ability of mutant PPARgamma to compete with WT receptor for binding to a PPAR regulatory element (PPRE)-containing promoter. By determining the ratio of mutant and WT receptors bound to a PPRE over time, we estimated the relative promoter turnover rate of each receptor. This assay demonstrated that PPARgamma bearing the P467L had a reduced promoter turnover rate compared with the F388L receptor, and over time out-competed the WT receptor for promoter binding sites. We propose that the P467L receptor is dominant negative because in a cell containing both WT and mutant receptors, the majority of the PPAR-regulated promoters will be occupied by the transcriptionally defective mutant receptor. In contrast, the F388L mutation lacks dominant-negative activity because its more rapid promoter turnover rate prevented it from out-competing the WT receptor for promoter binding sites.

  15. Pyrimidinergic Receptor Activation Controls Toxoplasma gondii Infection in Macrophages.

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    Aline Cristina Abreu Moreira-Souza

    Full Text Available Infection by the protozoan parasite Toxoplasma gondii is highly prevalent worldwide and may have serious clinical manifestations in immunocompromised patients. T. gondii is an obligate intracellular parasite that infects almost any cell type in mammalian hosts, including immune cells. The immune cells express purinergic P2 receptors in their membrane--subdivided into P2Y and P2X subfamilies--whose activation is important for infection control. Here, we examined the effect of treatment with UTP and UDP in mouse peritoneal macrophages infected with T. gondii tachyzoites. Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis. On the other hand, UTP and UDP treatments induced early egress of tachyzoites from infected macrophages, in a Ca2+-dependent manner, as shown by scanning electron microscopy analysis, and videomicroscopy. In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole. The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes. Our results suggest that the activity of P2Y host cell receptors controls T. gondii infection in macrophages, highlighting the importance of pyrimidinergic signaling for innate immune system response against infection. Finally the P2Y receptors should be considered as new target for the development of drugs against T. gondii infection.

  16. The biology of NK cells and their receptors affects clinical outcomes after hematopoietic cell transplantation (HCT).

    Science.gov (United States)

    Foley, Bree; Felices, Martin; Cichocki, Frank; Cooley, Sarah; Verneris, Michael R; Miller, Jeffrey S

    2014-03-01

    Natural killer (NK) cells were first identified for their capacity to reject bone marrow allografts in lethally irradiated mice without prior sensitization. Subsequently, human NK cells were detected and defined by their non-major histocompatibility complex (MHC)-restricted cytotoxicity toward transformed or virally infected target cells. Karre et al. later proposed 'the missing self hypothesis' to explain the mechanism by which self-tolerant cells could kill targets that had lost self MHC class I. Subsequently, the receptors that recognize MHC class I to mediate tolerance in the host were identified on NK cells. These class I-recognizing receptors contribute to the acquisition of function by a dynamic process known as NK cell education or licensing. In the past, NK cells were assumed to be short lived, but more recently NK cells have been shown to mediate immunologic memory to secondary exposures to cytomegalovirus infection. Because of their ability to lyse tumors with aberrant MHC class I expression and to produce cytokines and chemokines upon activation, NK cells may be primed by many stimuli, including viruses and inflammation, to contribute to a graft-versus-tumor effect. In addition, interactions with other immune cells support the therapeutic potential of NK cells to eradicate tumor and to enhance outcomes after hematopoietic cell transplantation.

  17. Activation of peroxisome proliferator-activated receptor-{alpha} enhances fatty acid oxidation in human adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kawada, Teruo, E-mail: fat@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-04-22

    Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. {yields} PPAR{alpha} activation also increased insulin-dependent glucose uptake in human adipocytes. {yields} PPAR{alpha} activation did not affect lipid accumulation in human adipocytes. {yields} PPAR{alpha} activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPAR{alpha} in adipocytes have been unclarified. We examined the functions of PPAR{alpha} using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPAR{alpha} by GW7647, a potent PPAR{alpha} agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPAR{gamma}, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPAR{alpha} activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPAR{gamma} is activated. On the other hand, PPAR{alpha} activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPAR{alpha}-dependent manner. Moreover, PPAR{alpha} activation increased the production of CO{sub 2} and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPAR{alpha} stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPAR{alpha} agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected

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

    Science.gov (United States)

    Mul, Joram D; van Boxtel, Ruben; Bergen, Dylan J M; Brans, Maike A D; Brakkee, Jan H; Toonen, Pim W; Garner, Keith M; Adan, Roger A H; Cuppen, Edwin

    2012-03-01

    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 the most common genetic cause of human obesity. In this study, we present the first functional Mc4r knockout model in the rat, resulting from an N-ethyl-N-nitrosourea mutagenesis-induced point mutation. In vitro observations revealed impaired membrane-binding and subsequent nonfunctionality of the receptor, whereas in vivo observations showed that functional loss of MC4R increased body weight, food intake, white adipose mass, and changed substrate preference. In addition, intracerebroventricular (ICV) administration of Agouti-Related Protein(79-129) (AgRP(79-129)), an MC4R inverse agonist, or Melanotan-II (MTII), an MC4R agonist, did affect feeding behavior in wild-type rats but not in homozygous mutant rats, confirming complete loss of MC4R function in vivo. Finally, ICV administration of MTII induced excessive grooming behavior in wild-type rats, whereas this effect was absent in homozygous mutant rats, indicating that MTII-induced grooming behavior is exclusively regulated via MC4R pathways. Taken together, we expect that the MC4R rat model described here will be a valuable tool for studying monogenic obesity in humans. More specifically, the relative big size and increased cognitive capacity of rats as compared to mice will facilitate complex behavioral studies and detailed mechanistic studies regarding central function of MC4R, both of which ultimately may help to further understand the specific mechanisms that induce obesity during loss of MC4R function.

  19. Neurohumoral activation in heart failure: the role of adrenergic receptors

    Directory of Open Access Journals (Sweden)

    Patricia C. Brum

    2006-09-01

    Full Text Available Heart failure (HF is a common endpoint for many forms of cardiovascular disease and a significant cause of morbidity and mortality. The development of end-stage HF often involves an initial insult to the myocardium that reduces cardiac output and leads to a compensatory increase in sympathetic nervous system activity. Acutely, the sympathetic hyperactivity through the activation of beta-adrenergic receptors increases heart rate and cardiac contractility, which compensate for decreased cardiac output. However, chronic exposure of the heart to elevated levels of catecholamines released from sympathetic nerve terminals and the adrenal gland may lead to further pathologic changes in the heart, resulting in continued elevation of sympathetic tone and a progressive deterioration in cardiac function. On a molecular level, altered beta-adrenergic receptor signaling plays a pivotal role in the genesis and progression of HF. beta-adrenergic receptor number and function are decreased, and downstream mechanisms are altered. In this review we will present an overview of the normal beta-adrenergic receptor pathway in the heart and the consequences of sustained adrenergic activation in HF. The myopathic potential of individual components of the adrenergic signaling will be discussed through the results of research performed in genetic modified animals. Finally, we will discuss the potential clinical impact of beta-adrenergic receptor gene polymorphisms for better understanding the progression of HF.A insuficiência cardíaca (IC é a via final comum da maioria das doenças cardiovasculares e uma das maiores causas de morbi-mortalidade. O desenvolvimento do estágio final da IC freqüentemente envolve um insulto inicial do miocárdio, reduzindo o débito cardíaco e levando ao aumento compensatório da atividade do sistema nervoso simpático (SNS. Existem evidências de que apesar da exposição aguda ser benéfica, exposições crônicas a elevadas concentra

  20. Interleukin-1-induced activation of the small GTPase Rac1 depends on receptor internalization and regulates gene expression.

    Science.gov (United States)

    Windheim, Mark; Hansen, Benjamin

    2014-01-01

    Interleukin 1 (IL-1) triggers the internalization of its cognate receptor from the plasma membrane. We recently demonstrated that this internalization is of critical importance for the IL-1-induced gene expression. In this study we report that the IL-1-induced activation of the small GTPase Rac1 requires receptor endocytosis. We further show that the depletion of Rac1 reduces the IL-1-dependent gene expression without affecting signaling events that are initiated at the plasma membrane. Collectively, we provide evidence for a key role of Rac1 in a pathway that regulates IL-1-induced gene expression depending on receptor endocytosis.

  1. Activation of Penile Proadipogenic Peroxisome Proliferator-Activated Receptor with an Estrogen: Interaction with Estrogen Receptor Alpha during Postnatal Development

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    Mahmoud M. Mansour

    2008-01-01

    Full Text Available Exposure to the estrogen receptor alpha (ER ligand diethylstilbesterol (DES between neonatal days 2 to 12 induces penile adipogenesis and adult infertility in rats. The objective of this study was to investigate the in vivo interaction between DES-activated ER and the proadipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPAR. Transcripts for PPARs , , and and 1a splice variant were detected in Sprague-Dawley normal rat penis with PPAR predominating. In addition, PPAR1b and PPAR2 were newly induced by DES. The PPAR transcripts were significantly upregulated with DES and reduced by antiestrogen ICI 182, 780. At the cellular level, PPAR protein was detected in urethral transitional epithelium and stromal, endothelial, neuronal, and smooth muscular cells. Treatment with DES activated ER and induced adipocyte differentiation in corpus cavernosum penis. Those adipocytes exhibited strong nuclear PPAR expression. These results suggest a biological overlap between PPAR and ER and highlight a mechanism for endocrine disruption.

  2. Environmental layout complexity affects neural activity during navigation in humans.

    Science.gov (United States)

    Slone, Edward; Burles, Ford; Iaria, Giuseppe

    2016-05-01

    Navigating large-scale surroundings is a fundamental ability. In humans, it is commonly assumed that navigational performance is affected by individual differences, such as age, sex, and cognitive strategies adopted for orientation. We recently showed that the layout of the environment itself also influences how well people are able to find their way within it, yet it remains unclear whether differences in environmental complexity are associated with changes in brain activity during navigation. We used functional magnetic resonance imaging to investigate how the brain responds to a change in environmental complexity by asking participants to perform a navigation task in two large-scale virtual environments that differed solely in interconnection density, a measure of complexity defined as the average number of directional choices at decision points. The results showed that navigation in the simpler, less interconnected environment was faster and more accurate relative to the complex environment, and such performance was associated with increased activity in a number of brain areas (i.e. precuneus, retrosplenial cortex, and hippocampus) known to be involved in mental imagery, navigation, and memory. These findings provide novel evidence that environmental complexity not only affects navigational behaviour, but also modulates activity in brain regions that are important for successful orientation and navigation.

  3. Visualising androgen receptor activity in male and female mice.

    Directory of Open Access Journals (Sweden)

    D Alwyn Dart

    Full Text Available Androgens, required for normal development and fertility of males and females, have vital roles in the reproductive tract, brain, cardiovascular system, smooth muscle and bone. Androgens function via the androgen receptor (AR, a ligand-dependent transcription factor. To assay and localise AR activity in vivo we generated the transgenic "ARE-Luc" mouse, expressing a luciferase reporter gene under the control of activated endogenous AR. In vivo imaging of androgen-mediated luciferase activity revealed several strongly expressing tissues in the male mouse as expected and also in certain female tissues. In males the testes, prostate, seminal vesicles and bone marrow all showed high AR activity. In females, strong activity was seen in the ovaries, uterus, omentum tissue and mammary glands. In both sexes AR expression and activity was also found in salivary glands, the eye (and associated glands, adipose tissue, spleen and, notably, regions of the brain. Luciferase protein expression was found in the same cell layers as androgen receptor expression. Additionally, mouse AR expression and activity correlated well with AR expression in human tissues. The anti-androgen bicalutamide reduced luciferase signal in all tissues. Our model demonstrates that androgens can act in these tissues directly via AR, rather than exclusively via androgen aromatisation to estrogens and activation of the estrogen receptor. Additionally, it visually demonstrates the fundamental importance of AR signalling outside the normal role in the reproductive organs. This model represents an important tool for physiological and developmental analysis of androgen signalling, and for characterization of known and novel androgenic or antiandrogenic compounds.

  4. Monocyte Signal Transduction Receptors in Active and Latent Tuberculosis

    Directory of Open Access Journals (Sweden)

    Magdalena Druszczynska

    2013-01-01

    Full Text Available The mechanisms that promote either resistance or susceptibility to TB disease remain insufficiently understood. Our aim was to compare the expression of cell signaling transduction receptors, CD14, TLR2, CD206, and β2 integrin LFA-1 on monocytes from patients with active TB or nonmycobacterial lung disease and healthy individuals with M.tb latency and uninfected controls to explain the background of the differences between clinical and subclinical forms of M.tb infection. A simultaneous increase in the expression of the membrane bound mCD14 receptor and LFA-1 integrin in patients with active TB may be considered a prodrome of breaking immune control by M.tb bacilli in subjects with the latent TB and absence of clinical symptoms.

  5. Manipulation of P2X Receptor Activities by Light Stimulation

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    Sang Seong Kim

    2016-01-01

    Full Text Available P2X receptors are involved in amplification of inflammatory responses in peripheral nociceptive fibers and in mediating pain-related signals to the CNS. Control of P2X activation has significant importance in managing unwanted hypersensitive neuron responses. To overcome the limitations of chemical ligand treatment, optical stimulation methods of optogenetics and photoswitching achieve efficient control of P2X activation while allowing specificity at the target site and convenient stimulation by light illumination. There are many potential applications for photosensitive elements, such as improved uncaging methods, photoisomerizable ligands, photoswitches, and gold nanoparticles. Each technique has both advantages and downsides, and techniques are selected according to the purpose of the application. Technical advances not only provide novel approaches to manage inflammation or pain mediated by P2X receptors but also suggest a similar approach for controlling other ion channels.

  6. Estrogen receptor- and aryl hydrocarbon receptor- mediated activities of a coal-tar creosote

    Energy Technology Data Exchange (ETDEWEB)

    Fielden, M.R.; Wu, Z.F.; Sinal, C.J.; Jury, H.H.; Bend, J.R.; Hammond, G.L.; Zacharewski, T.R. [Michigan State University, East Lansing, MI (USA). Dept. of Biochemistry

    2000-05-01

    A coal-tar creosote was examined for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activity using a battery of mechanistically based assays. In vitro, creosote was found to bind the mouse ER, bind to the human sex hormone-binding globulin, and elicit partial agonist activity in reporter gene assays in transiently transfected MCF-7 cells. Based on competitive binding to the mouse ER, creosote contains approximately 165 mg/L of estradiol- equivalents. Creosote effectively transformed the AhR in vitro and induced a Cyp 1a1-regulated luciferase reporter gene in transiently transfected Hepa 1c1c7 cells. Based on dose-response curves, creosote contains approximately 730 mg/L of dioxin-equivalents. Creosote did not exhibit any AhR-mediated antiestrogenic activity in vitro. In vivo, creosote significantly induced liver pentoxyresorufin O- depentylation and ethoxyresorufin-O-deethylation (EROD) in a dose-dependent manner in ovariectomized (OVX) ICR mice, but did not increase uterine weight wet or vaginal cornification, due possibly to AhR-mediated antiestrogenic activity. In OVX DBA/2 mice, a strain less responsive to AhR ligands, creosote induced liver EROD to a lesser extent, but still did not show an increase in uterine wet weight or vaginal cornification. These results demonstrate that coal- tar creosote exhibits AhR- and ER-mediated activity in vitro, but its dioxinlike activity may suppress estrogenic response in vivo.

  7. Estrogen receptor- and aryl hydrocarbon receptor-mediated activities of a coal-tar creosote

    Energy Technology Data Exchange (ETDEWEB)

    Fielden, M.R.; Wu, Z.F.; Sinal, C.J.; Jury, H.H.; Bend, J.R.; Hammond, G.L.; Zacharewski, T.R.

    2000-05-01

    A coal-tar creosote was examined for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activity using a battery of mechanistically based assays. In vitro, creosote was found to bind to the mouse ER, bind to the human sex hormone-binding globulin, and elicit partial agonist activity in reporter gene assays in transiently transfected MCF-7 cells. Based on competitive binding to the mouse ER, creosote contains approximately 165 mg/L of estradiol-equivalents. Creosote effectively transformed the AhR in vitro and induced a Cyplal-regulated luciferase reporter gene in transiently transfected Hepa 1c1c7 cells. Based on dose-response curves, creosote contains approximately 730 mg/L of dioxin-equivalents. Creosote did not exhibit any AhR-mediated antiestrogenic activity in vitro. In vivo, creosote significantly induced liver pentoxyresorufin O-depentylation and ethoxyresorufin-O-deethylation (EROD) in a dose-dependent manner in ovariectomized (OVX) ICR mice, but did not increase uterine weight wet or vaginal cornification, due possibly to AhR-mediated antiestrogenic activity. In OVX DBA/2 mice, a strain less responsive to AhR ligands, creosote induced liver EROD to a lesser extent, but still did not show an increase in uterine wet weight or vaginal cornification. These results demonstrate that coal-tar creosote exhibits AhR- and ER-mediated activity in vitro, but its dioxinlike activity may suppress estrogenic responses in vivo.

  8. A novel hydroxyfuroic acid compound as an insulin receptor activator – structure and activity relationship of a prenylindole moiety to insulin receptor activation

    Directory of Open Access Journals (Sweden)

    Tsai Henry J

    2009-07-01

    Full Text Available Abstract Background Diabetes Mellitus is a chronic disease and many patients of which require frequent subcutaneous insulin injection to maintain proper blood glucose levels. Due to the inconvenience of insulin administration, an orally active insulin replacement has long been a prime target for many pharmaceutical companies. Demethylasterriquinone (DMAQ B1, extracted from tropical fungus, Pseudomassaria sp., has been reported to be an orally effective agent at lowering circulating glucose levels in diabetic (db/db mice; however, the cytotoxicity associated with the quinone moiety has not been addressed thus far. Methods A series of hydroxyfuroic acid compounds were synthesized and tested for their efficacies at activating human insulin receptor. Cytotoxicity to Chinese hamster ovary cells, selectivities over insulin-like growth factor-1 (IGF-1, epidermal growth factor (EGF, and fibroblast growth factor (FGF receptors were examined in this study. Result and Conclusion This study reports a new non-quinone DMAQ B1 derivative, a hydroxyfuroic acid compound (D-410639, which is 128 fold less cytotoxic as DMAQ B1 and as potent as compound 2, a DMAQ B1 synthetic derivative from Merck, at activating human insulin receptor. D-410639 has little activation potential on IGF-1 receptor but is a moderate inhibitor to EGF receptor. Structure and activity relationship of the prenylindole moiety to insulin receptor activation is discussed.

  9. Hippocampal somatostatin receptors and modulation of adenylyl cyclase activity in histamine-treated rats.

    Science.gov (United States)

    Puebla, L; Rodríguez-Martín, E; Arilla, E

    1996-01-01

    In the present study, the effects of an intracerebroventricular (i.c.v.) dose of histamine (0.1, 1.0 or 10.0 micrograms) on the hippocampal somatostatin (SS) receptor/effector system in Wistar rats were investigated. In view of the rapid onset of histamine action, the effects of histamine on the somatostatinergic system were studied 2 h after its administration. Hippocampal SS-like immunoreactivity (SSLI) levels were not modified by any of the histamine doses studied. SS-mediated inhibition of basal and forskolin (FK)-stimulated adenylyl cyclase (AC) activity was markedly increased in hippocampal membranes from rats treated with 10 micrograms of histamine (23% +/- 1% vs. 17% +/- 1% and 37% +/- 2% vs. 23% +/- 1%, respectively). In contrast, neither the basal nor the FK-stimulated enzyme activities were affected by histamine administration. The functional activity of the hippocampal guanine-nucleotide binding inhibitory protein (Gi protein), as assessed by the capacity of the stable GTP analogue 5'-guanylylimidodiphosphate (Gpp[NH]p) to inhibit FK-stimulated AC activity, was not modified by histamine administration. These data suggest that the increased response of the enzyme to SS was not related to an increased functional activity of Gi proteins. In fact, the increased AC response to SS in hippocampal membranes from histamine (10 micrograms)-treated rats was associated with quantitative changes in the SS receptors. Equilibrium binding data obtained with [125I]Tyr11-SS indicate an increase in the number with specific SS receptors (541 +/- 24 vs. 365 +/- 16 fmol/mg protein, P histamine (10 micrograms)-treated rats as compared to control animals. With the aim of determining if these changes were related to histamine binding to its specific receptor sites, the histaminergic H1 and H2 receptor antagonists mepyramine and cimetidine, respectively, were administered 1 h before histamine injection. The pretreatment with mepyramine or cimetidine induced an increase in the

  10. Toll-like receptor 7 affects the pathogenesis of non-alcoholic fatty liver disease

    Science.gov (United States)

    Kim, Sokho; Park, Surim; Kim, Bumseok; Kwon, Jungkee

    2016-01-01

    Recently, a possible link between toll-like receptor 7 (TLR7) and liver disease was suggested, although it was limited to fibrosis. Based on this report, we investigated whether TLR7 has a pivotal role in non-alcoholic fatty liver disease (NAFLD). The TLR7 signaling pathway, which is activated by imiquimod (TLR7 ligand) naturally, induced autophagy and released insulin-like growth factor 1 (IGF-1) into medium from hepatocytes. Lipid accumulation induced by unsaturated fatty acid (UFA; arachidonic acid:oleic acid = 1:1) in hepatocytes, was attenuated in TLR7 and autophagy activation. Interestingly, TLR7 activation attenuated UFA-induced lipid peroxidation products, such as malondialdehyde (MDA) and 4-Hydroxy-2-Nonenal (4-HNE). To clarify a possible pathway between TLR7 and lipid peroxidation, we treated hepatocytes with MDA and 4-HNE. MDA and 4-HNE induced 2-folds lipid accumulation in UFA-treated hepatocytes via blockade of the TLR7 signaling pathway’s IGF-1 release compared to only UFA-treated hepatocytes. In vivo experiments carried out with TLR7 knockout mice produced results consistent with in vitro experiments. In conclusion, TLR7 prevents progression of NAFLD via induced autophagy and released IGF-1 from liver. These findings suggest a new therapeutic strategy for the treatment of NAFLD. PMID:27279075

  11. Toll-like receptor 7 affects the pathogenesis of non-alcoholic fatty liver disease.

    Science.gov (United States)

    Kim, Sokho; Park, Surim; Kim, Bumseok; Kwon, Jungkee

    2016-06-09

    Recently, a possible link between toll-like receptor 7 (TLR7) and liver disease was suggested, although it was limited to fibrosis. Based on this report, we investigated whether TLR7 has a pivotal role in non-alcoholic fatty liver disease (NAFLD). The TLR7 signaling pathway, which is activated by imiquimod (TLR7 ligand) naturally, induced autophagy and released insulin-like growth factor 1 (IGF-1) into medium from hepatocytes. Lipid accumulation induced by unsaturated fatty acid (UFA; arachidonic acid:oleic acid = 1:1) in hepatocytes, was attenuated in TLR7 and autophagy activation. Interestingly, TLR7 activation attenuated UFA-induced lipid peroxidation products, such as malondialdehyde (MDA) and 4-Hydroxy-2-Nonenal (4-HNE). To clarify a possible pathway between TLR7 and lipid peroxidation, we treated hepatocytes with MDA and 4-HNE. MDA and 4-HNE induced 2-folds lipid accumulation in UFA-treated hepatocytes via blockade of the TLR7 signaling pathway's IGF-1 release compared to only UFA-treated hepatocytes. In vivo experiments carried out with TLR7 knockout mice produced results consistent with in vitro experiments. In conclusion, TLR7 prevents progression of NAFLD via induced autophagy and released IGF-1 from liver. These findings suggest a new therapeutic strategy for the treatment of NAFLD.

  12. Discovery of novel protease activated receptors 1 antagonists with potent antithrombotic activity in vivo.

    Science.gov (United States)

    Perez, Michel; Lamothe, Marie; Maraval, Catherine; Mirabel, Etienne; Loubat, Chantal; Planty, Bruno; Horn, Clemens; Michaux, Julien; Marrot, Sebastien; Letienne, Robert; Pignier, Christophe; Bocquet, Arnaud; Nadal-Wollbold, Florence; Cussac, Didier; de Vries, Luc; Le Grand, Bruno

    2009-10-08

    Protease activated receptors (PARs) or thrombin receptors constitute a class of G-protein-coupled receptors (GPCRs) implicated in the activation of many physiological mechanisms. Thus, thrombin activates many cell types such as vascular smooth muscle cells, leukocytes, endothelial cells, and platelets via activation of these receptors. In humans, thrombin-induced platelet aggregation is mediated by one subtype of these receptors, termed PAR1. This article describes the discovery of new antagonists of these receptors and more specifically two compounds: 2-[5-oxo-5-(4-pyridin-2-ylpiperazin-1-yl)penta-1,3-dienyl]benzonitrile 36 (F 16618) and 3-(2-chlorophenyl)-1-[4-(4-fluorobenzyl)piperazin-1-yl]propenone 39 (F 16357), obtained after optimization. Both compounds are able to inhibit SFLLR-induced human platelet aggregation and display antithrombotic activity in an arteriovenous shunt model in the rat after iv or oral administration. Furthermore, these compounds are devoid of bleeding side effects often observed with other types of antiplatelet drugs, which constitutes a promising advantage for this new class of antithrombotic agents.

  13. Intolerance of uncertainty correlates with insula activation during affective ambiguity.

    Science.gov (United States)

    Simmons, Alan; Matthews, Scott C; Paulus, Martin P; Stein, Murray B

    2008-01-10

    Intolerance of uncertainty (IU), or the increased affective response to situations with uncertain outcomes, is an important component process of anxiety disorders. Increased IU is observed in panic disorder (PD), obsessive compulsive disorder (OCD) and generalized anxiety disorder (GAD), and is thought to relate to dysfunctional behaviors and thought patterns in these disorders. Identifying what brain systems are associated with IU would contribute to a comprehensive model of anxiety processing, and increase our understanding of the neurobiology of anxiety disorders. Here, we used a behavioral task, Wall of Faces (WOFs), during functional magnetic resonance imaging (fMRI), which probes both affect and ambiguity, to examine the neural circuitry of IU in 14 (10 females) college age (18.8 years) subjects. All subjects completed the Intolerance of Uncertainty Scale (IUS), Anxiety Sensitivity Index (ASI), and a measure of neuroticism (i.e. the NEO-N). IUS scores but neither ASI nor NEO-N scores, correlated positively with activation in bilateral insula during affective ambiguity. Thus, the experience of IU during certain types of emotion processing may relate to the degree to which bilateral insula processes uncertainty. Previously observed insula hyperactivity in anxiety disorder individuals may therefore be directly linked to altered processes of uncertainty.

  14. Nanoparticle-induced unfolding of fibrinogen promotes Mac-1 receptor activation and inflammation

    Science.gov (United States)

    Deng, Zhou J.; Liang, Mingtao; Monteiro, Michael; Toth, Istvan; Minchin, Rodney F.

    2011-01-01

    The chemical composition, size, shape and surface characteristics of nanoparticles affect the way proteins bind to these particles, and this in turn influences the way in which nanoparticles interact with cells and tissues. Nanomaterials bound with proteins can result in physiological and pathological changes, including macrophage uptake, blood coagulation, protein aggregation and complement activation, but the mechanisms that lead to these changes remain poorly understood. Here, we show that negatively charged poly(acrylic acid)-conjugated gold nanoparticles bind to and induce unfolding of fibrinogen, which promotes interaction with the integrin receptor, Mac-1. Activation of this receptor increases the NF-κB signalling pathway, resulting in the release of inflammatory cytokines. However, not all nanoparticles that bind to fibrinogen demonstrated this effect. Our results show that the binding of certain nanoparticles to fibrinogen in plasma offers an alternative mechanism to the more commonly described role of oxidative stress in the inflammatory response to nanomaterials.

  15. DMPD: Receptor tyrosine kinases and the regulation of macrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14726496 Receptor tyrosine kinases and the regulation of macrophage activation. Cor...(.csml) Show Receptor tyrosine kinases and the regulation of macrophage activation. PubmedID 14726496 Title ...Receptor tyrosine kinases and the regulation of macrophage activation. Authors Co

  16. Uteroplacental insufficiency down regulates insulin receptor and affects expression of key enzymes of long-chain fatty acid (LCFA metabolism in skeletal muscle at birth

    Directory of Open Access Journals (Sweden)

    Puglianiello Antonella

    2008-05-01

    Full Text Available Abstract Background Epidemiological studies have revealed a relationship between early growth restriction and the subsequent development of insulin resistance and type 2 diabetes. Ligation of the uterine arteries in rats mimics uteroplacental insufficiency and serves as a model of intrauterine growth restriction (IUGR and subsequent developmental programming of impaired glucose tolerance, hyperinsulinemia and adiposity in the offspring. The objective of this study was to investigate the effects of uterine artery ligation on the skeletal muscle expression of insulin receptor and key enzymes of LCFA metabolism. Methods Bilateral uterine artery ligation was performed on day 19 of gestation in Sprague-Dawley pregnant rats. Muscle of the posterior limb was dissected at birth and processed by real-time RT-PCR to analyze the expression of insulin receptor, ACCα, ACCβ (acetyl-CoA carboxylase alpha and beta subunits, ACS (acyl-CoA synthase, AMPK (AMP-activated protein kinase, alpha2 catalytic subunit, CPT1B (carnitine palmitoyltransferase-1 beta subunit, MCD (malonyl-CoA decarboxylase in 14 sham and 8 IUGR pups. Muscle tissue was treated with lysis buffer and Western immunoblotting was performed to assay the protein content of insulin receptor and ACC. Results A significant down regulation of insulin receptor protein (p Conclusion Our data suggest that uteroplacental insufficiency may affect skeletal muscle metabolism down regulating insulin receptor and reducing the expression of key enzymes involved in LCFA formation and oxidation.

  17. Cranial irradiation modulates hypothalamic-pituitary-adrenal axis activity and corticosteroid receptor expression in the hippocampus of juvenile rat.

    Science.gov (United States)

    Velickovic, Natasa; Djordjevic, Ana; Drakulic, Dunja; Stanojevic, Ivana; Secerov, Bojana; Horvat, Anica

    2009-01-01

    Glucocorticoids, essential for normal hypothalamic-pituitary-adrenal (HPA) axis activity, exert their action on the hippocampus through two types of corticosteroid receptors: the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). Recent studies report that exposure of juvenile rats to cranial irradiation adversely affects HPA axis stability leading to its activation along with radiation- induced inflammation. This study was aimed to examine the acute effects of radiation on HPA axis activity and hippocampal corticosteroid receptor expression in 18-day-old rats. Since immobilization was part of irradiation procedure, both irradiated and sham-irradiated animals were exposed to this unavoidable stress. Our results demonstrate that the irradiated rats exhibited different pattern of corticosteroid receptor expression and hormone levels compared to respective controls. These differences included upregulation of GR protein in the hippocampus with a concomitant elevation of GR mRNA and an increase in circulating level of corticosterone. In addition, the expression of MR, both at the level of protein and gene expression, was not altered. Taken together, this study demonstrates that cranial irradiation in juvenile rats leads to enhanced HPA axis activity and increased relative GR/MR ratio in hippocampus. The present paper intends to show that neuroendocrine response of normal brain tissue to localized irradiation comprise both activation of HPA axis and altered corticosteroid receptor balance, probably as consequence of innate immune activation.

  18. Schistosomiasis differentially affects vasoconstrictor responses: up-regulation of 5-HT receptor-mediated aorta contraction

    Directory of Open Access Journals (Sweden)

    Suellen D'Arc dos Santos Oliveira

    2011-06-01

    Full Text Available Schistosomiasis, classified by the World Health Organization as a neglected tropical disease, is an intravascular parasitic disease associated to a chronic inflammatory state. Evidence implicating inflammation in vascular dysfunction continues to mount, which, broadly defined, reflects a failure in the control of intracellular Ca2+ and consequently, vascular contraction. Therefore, we measured aorta contraction induced by 5-hydroxytryptamine (5-HT and endothelin-1 (ET-1, two important regulators of vascular contraction. Isometric aortic contractions were determined in control and Schistosoma mansoni-infected mice. In the infected animals, 5-HT induced a 50% higher contraction in relation to controls and we also observed an increased contraction in response to Ca2+ mobilisation from sarcoplasmic reticulum. Nevertheless, Rho kinase inhibition reduced the contraction in response to 5-HT equally in both groups, discarding an increase of the contractile machinery sensitivity to Ca2+. Furthermore, no alteration was observed for contractions induced by ET-1 in both groups. Our data suggest that an immune-vascular interaction occurs in schistosomiasis, altering vascular contraction outside the mesenteric portal system. More importantly, it affects distinct intracellular signalling involved in aorta contraction, in this case increasing 5-HT receptor signalling.

  19. LRRK2 affects vesicle trafficking, neurotransmitter extracellular level and membrane receptor localization.

    Directory of Open Access Journals (Sweden)

    Rossana Migheli

    Full Text Available The leucine-rich repeat kinase 2 (LRRK2 gene was found to play a role in the pathogenesis of both familial and sporadic Parkinson's disease (PD. LRRK2 encodes a large multi-domain protein that is expressed in different tissues. To date, the physiological and pathological functions of LRRK2 are not clearly defined. In this study we have explored the role of LRRK2 in controlling vesicle trafficking in different cellular or animal models and using various readouts. In neuronal cells, the presence of LRRK2(G2019S pathological mutant determines increased extracellular dopamine levels either under basal conditions or upon nicotine stimulation. Moreover, mutant LRRK2 affects the levels of dopamine receptor D1 on the membrane surface in neuronal cells or animal models. Ultrastructural analysis of PC12-derived cells expressing mutant LRRK2(G2019S shows an altered intracellular vesicle distribution. Taken together, our results point to the key role of LRRK2 to control vesicle trafficking in neuronal cells.

  20. LRRK2 Affects Vesicle Trafficking, Neurotransmitter Extracellular Level and Membrane Receptor Localization

    Science.gov (United States)

    Spissu, Ylenia; Sanna, Giovanna; Xiong, Yulan; Dawson, Ted M.; Dawson, Valina L.; Galioto, Manuela; Rocchitta, Gaia; Biosa, Alice; Serra, Pier Andrea; Carri, Maria Teresa; Crosio, Claudia; Iaccarino, Ciro

    2013-01-01

    The leucine-rich repeat kinase 2 (LRRK2) gene was found to play a role in the pathogenesis of both familial and sporadic Parkinson’s disease (PD). LRRK2 encodes a large multi-domain protein that is expressed in different tissues. To date, the physiological and pathological functions of LRRK2 are not clearly defined. In this study we have explored the role of LRRK2 in controlling vesicle trafficking in different cellular or animal models and using various readouts. In neuronal cells, the presence of LRRK2G2019S pathological mutant determines increased extracellular dopamine levels either under basal conditions or upon nicotine stimulation. Moreover, mutant LRRK2 affects the levels of dopamine receptor D1 on the membrane surface in neuronal cells or animal models. Ultrastructural analysis of PC12-derived cells expressing mutant LRRK2G2019S shows an altered intracellular vesicle distribution. Taken together, our results point to the key role of LRRK2 to control vesicle trafficking in neuronal cells. PMID:24167564

  1. Nephrin Contributes to Insulin Secretion and Affects Mammalian Target of Rapamycin Signaling Independently of Insulin Receptor.

    Science.gov (United States)

    Villarreal, Rodrigo; Mitrofanova, Alla; Maiguel, Dony; Morales, Ximena; Jeon, Jongmin; Grahammer, Florian; Leibiger, Ingo B; Guzman, Johanna; Fachado, Alberto; Yoo, Tae H; Busher Katin, Anja; Gellermann, Jutta; Merscher, Sandra; Burke, George W; Berggren, Per-Olof; Oh, Jun; Huber, Tobias B; Fornoni, Alessia

    2016-04-01

    Nephrin belongs to a family of highly conserved proteins with a well characterized function as modulators of cell adhesion and guidance, and nephrin may have a role in metabolic pathways linked to podocyte and pancreatic β-cell survival. However, this role is incompletely characterized. In this study, we developed floxed nephrin mice for pancreatic β-cell-specific deletion of nephrin, which had no effect on islet size and glycemia. Nephrin deficiency, however, resulted in glucose intolerance in vivo and impaired glucose-stimulated insulin release ex vivo Glucose intolerance was also observed in eight patients with nephrin mutations compared with three patients with other genetic forms of nephrotic syndrome or nine healthy controls.In vitro experiments were conducted to investigate if nephrin affects autocrine signaling through insulin receptor A (IRA) and B (IRB), which are both expressed in human podocytes and pancreatic islets. Coimmunoprecipitation of nephrin and IRB but not IRA was observed and required IR phosphorylation. Nephrin per se was sufficient to induce phosphorylation of p70S6K in an phosphatidylinositol 3-kinase-dependent but IR/Src-independent manner, which was not augmented by exogenous insulin. These results suggest a role for nephrin as an independent modulator of podocyte and pancreatic β-cell nutrient sensing in the fasting state and the potential of nephrin as a drug target in diabetes.

  2. Cigarette Smoke Affects ABCAl Expression via Liver X Receptor Nuclear Translocation in Human Keratinocytes

    Directory of Open Access Journals (Sweden)

    Claudia Sticozzi

    2010-09-01

    Full Text Available Cutaneous tissue is the first barrier against outdoor insults. The outer most layer of the skin, the stratum corneum (SC, is formed by corneocytes embedded in a lipid matrix (cholesterol, ceramide and fatty acids. Therefore, the regulation of lipids and, in particular, of cholesterol homeostasis in the skin is of great importance. ABCA1 is a membrane transporter responsible for cholesterol efflux and plays a key role in maintaining cellular cholesterol levels. Among the many factors that have been associated with skin diseases, the environmental stressor cigarette smoke has been recently studied. In the present study, we demonstrate that ABCA1 expression in human cells (HaCaT was increased (both mRNA and protein levels after CS exposure. This effect was mediated by the inhibition of NFkB (aldehydes adducts formation that allows the translocation of liver X receptor (LXR. These findings suggest that passive smoking may play a role in skin cholesterol levels and thus affect cutaneous tissues functions.

  3. Bioluminescence imaging of estrogen receptor activity during breast cancer progression.

    Science.gov (United States)

    Vantaggiato, Cristina; Dell'Omo, Giulia; Ramachandran, Balaji; Manni, Isabella; Radaelli, Enrico; Scanziani, Eugenio; Piaggio, Giulia; Maggi, Adriana; Ciana, Paolo

    2016-01-01

    Estrogen receptors (ER) are known to play an important regulatory role in mammary gland development as well as in its neoplastic transformation. Although several studies highlighted the contribution of ER signaling in the breast transformation, little is known about the dynamics of ER state of activity during carcinogenesis due to the lack of appropriate models for measuring the extent of receptor signaling in time, in the same animal. To this aim, we have developed a reporter mouse model for the non-invasive in vivo imaging of ER activity: the ERE-Luc reporter mouse. ERE-Luc is a transgenic mouse generated with a firefly luciferase (Luc) reporter gene driven by a minimal promoter containing an estrogen responsive element (ERE). This model allows to measure receptor signaling in longitudinal studies by bioluminescence imaging (BLI). Here, we have induced sporadic mammary cancers by treating systemically ERE-Luc reporter mice with DMBA (9,10-dimethyl 1,2-benzanthracene) and measured receptor signaling by in vivo imaging in individual animals from early stage until a clinically palpable tumor appeared in the mouse breast. We showed that DMBA administration induces an increase of bioluminescence in the whole abdominal area 6 h after treatment, the signal rapidly disappears. Several weeks later, strong bioluminescence is observed in the area corresponding to the mammary glands. In vivo and ex vivo imaging analysis demonstrated that this bioluminescent signal is localized in the breast area undergoing neoplastic transformation. We conclude that this non-invasive assay is a novel relevant tool to identify the activation of the ER signaling prior the morphological detection of the neoplastic transformation.

  4. Effects of coriaria lactone-activated, astrocyte-conditioned medium on estrogen receptor and progesterone receptor expression in rat cortical and hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    Jie Rong; Shuhua Zhang

    2009-01-01

    BACKGROUND: Coriaria lactone-activated astrocytes released bioactive substances that eventually caused epilepsy.OBJECTIVE: It has been suggested that activated astrocytes alter the expression of the estrogen receptor and progesterone receptor by releasing bioactive substances during epilepsy, thereby affecting neuronal activity in the brain. This study was designed to observe the expression of the estrogen receptor and the progesterone receptor in rat brain following lateral ventricle injection of coriaria lactone-activated, astrocyte-conditioned medium.DESIGN AND SETTING: This immunohistochemical, randomized, controlled, animal study was conducted at the Department of Pathology, Hospital Affiliated to Binzhou Medical College, China.MATERIAL: Coriaria lactone was provided by Huaxi Pharmaceutical Factory, China.METHODS: Forty adult, healthy, male, Sprague Dawley rats were randomly assigned into two groups. Astrocyte-conditioned medium (10 μL) was injected into rat lateral ventricle in the control group (n = 8). Coriaria lactone-activated, astrocyte-conditioned medium (10 μL) was infused into the rat lateral ventricle in the coriaria lactone group (n = 32). At 2, 4, 8 and 12 hours following injection, rats were sacrificed and subjected to immunohistochemistry. Eight rats were studied at each time point.MAIN OUTCOME MEASURES: Behavioral changes were observed in rats of both groups. Expression of the estrogen receptor and the progesterone receptor in rat cortical and hippocampal neurons was measured using immunohistochemistry.RESULTS: Four hours after injection, estrogen receptor levels in rat cortical and hippocampal neurons were significantly higher in the coriaria lactone group than in the control group (P < 0.05). Progesterone receptor levels were significantly lower in the coriaria lactone group than in the control group (P < 0.05). Seizures were not observed in the control group. In the coriaria lactone group, convulsions appeared 30 minutes after injection

  5. UV ACTIVATION OF RECEPTOR TYROSINE KINASE-ACTIVITY

    NARCIS (Netherlands)

    COFFER, PJ; BURGERING, BMT; PEPPELENBOSCH, MP; BOS, JL; KRUIJER, W

    1995-01-01

    The exposure of mammalian cells to ultraviolet radiation (UV) may lead to DNA damage resulting in mutation and thus possibly cancer, while irradiation can further act as a potent tumour promoter. In addition UV induces p21ras-mediated signalling leading to activation of transcription factors such as

  6. Peroxisome Proliferator–Activated Receptors and The Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2009-04-01

    Full Text Available BACKGROUND: Obesity is a growing threat to global health by virtue of its association with insulin resistance, inflammation, hypertension, and dyslipidemia, collectively known as the metabolic syndrome (MetS. The nuclear receptors PPARα and PPARγ are therapeutic targets for hypertriglyceridemia and insulin resistance, respectively, and drugs that modulate these receptors are currently in clinical use. More recent work on the PPARδ has uncovered a dual benefit for both hypertriglyceridemia and insulin resistance, highlighting the broad potential of PPARs in the treatment of metabolic disease. CONTENT: We have learned much about PPARs, the metabolic fat sensors, and the molecular pathways they regulate. Through their distinct tissue distribution and specific target gene activation, the three PPARs together control diverse aspects of fatty acid metabolism, energy balance, insulin sensitivity glucose homeostasis, inflammation, hypertension and atherosclerosis. These studies have advanced our understanding of the etiology for the MetS. Mechanisms revealed by these studies highlight the importance of emerging concepts, such as the endocrine function of adipose tissue, tissue-tissue cross-talk and lipotoxicity, in the pathogenesis of type 2 diabetes mellitus and CVD. SUMMARY: The elucidation of key regulators of energy balance and insulin signaling have revolutionized our understanding of fat and sugar metabolism and their intimate link. The three ‘lipidsensing’ (PPARα, PPARγ and PPARδ exemplify this connection, regulating diverse aspects of lipid and glucose homeostasis, and serving as bonafide therapeutic targets. KEYWORDS: peroxisome proliferator, activated receptor, metabolic syndrome.

  7. Persistently active cannabinoid receptors mute a subpopulation of hippocampal interneurons.

    Science.gov (United States)

    Losonczy, Attila; Biró, Agota A; Nusser, Zoltan

    2004-02-03

    Cortical information processing requires an orchestrated interaction between a large number of pyramidal cells and albeit fewer, but highly diverse GABAergic interneurons (INs). The diversity of INs is thought to reflect functional and structural specializations evolved to control distinct network operations. Consequently, specific cortical functions may be selectively modified by altering the input-output relationship of unique IN populations. Here, we report that persistently active cannabinoid receptors, the site of action of endocannabinoids, and the psychostimulants marijuana and hashish, switch off the output (mute) of a unique class of hippocampal INs. In paired recordings between cholecystokinin-immunopositive, mossy fiber-associated INs, and their target CA3 pyramidal cells, no postsynaptic currents could be evoked with single presynaptic action potentials or with repetitive stimulations at frequencies <25 Hz. Cannabinoid receptor antagonists converted these "mute" synapses into high-fidelity ones. The selective muting of specific GABAergic INs, achieved by persistent presynaptic cannabinoid receptor activation, provides a state-dependent switch in cortical networks.

  8. Receptor conformation and constitutive activity in CCR5 chemokine receptor function and HIV infection.

    Science.gov (United States)

    Flanagan, Colleen A

    2014-01-01

    The CCR5 chemokine receptor mediates the effects of proinflammatory β-chemokines that stimulate chemotaxis, activation, and proliferation of macrophages and T cells. CCR5 is also the major coreceptor that mediates HIV infection in combination with CD4. Chemokine agonists of CCR5 stimulate the activation of cellular calcium and protein kinase signaling pathways that depend on the activation of Gαi and probably also Gαq in some cells. Chemokines also stimulate the recruitment of β-arrestin, which is required for clathrin-dependent receptor internalization and acts as a scaffold protein for the chemotaxis signaling complex that mobilizes the actin cytoskeleton. CCR5 is partially constitutively active for the activation of Gαi, but the physiological significance has not been studied. HIV binding to CCR5 also activates G protein and protein kinase signaling but, in addition, stimulates the production of proinflammatory cytokines, including TNF-α, and mobilizes the actin cytoskeleton to form the fusion pore that allows viral entry and subsequently supports viral replication in the cell. The CCR5 conformation that mediates the fusion of the viral and cell membranes is unknown, but it is probably distinct from the conformation that mediates G protein signaling. Nonpeptide CCR5 blockers are allosteric inverse agonists that increase dissociation of both chemokines and HIV envelope proteins, but this does not correlate with their ability to inhibit HIV infection. Nevertheless, the inverse agonist activity may ameliorate the immune activation that exacerbates AIDS pathogenesis. Inverse agonists of CCR5 have established efficacy for the treatment of AIDS, but may also be useful in preventing HIV infection.

  9. Natural Killer Cell Receptors and Cytotoxic Activity in Phosphomannomutase 2 Deficiency (PMM2-CDG.

    Directory of Open Access Journals (Sweden)

    Roberto García-López

    Full Text Available PMM2-CDG is the most common N-glycosylation defect and shows an increased risk of recurrent and/or severe, sometimes fatal, infections in early life. We hypothesized that natural killer (NK cells, as important mediators of the immune response against microbial pathogens and regulators of adaptive immunity, might be affected in this genetic disorder.To evaluate possible defects on PMM2-CDG NK peripheral blood cell number, killing activity and expression of membrane receptors.We studied fresh and activated NK cells from twelve PMM2-CDG cells. The number and expression of lymphoid surface receptors were studied by flow cytometry. The NK responsiveness (frequency of degranulated NK cells and killing activity against K562 target cells was determined in the NK cytotoxicity assay.We found an increase of blood NK cells in three patients with a severe phenotype. Two of them, who had suffered from moderate/severe viral infections during their first year of life, also had reduced T lymphocyte numbers. Patient activated NK cells showed increased expression of CD54 adhesion molecule and NKG2D and NKp46 activating receptors. NKp46 and 2B4 expression was inversely correlated with the expression of NKG2D in activated PMM2-CDG cells. Maximal NK activity against K562 target cells was similar in control and PMM2-CDG cells. Interestingly, the NK cell responsiveness was higher in patient cells. NKG2D and specially CD54 increased surface expression significantly correlated with the increased NK cell cytolytic activity according to the modulation of the killer activity by expression of triggering receptors and adhesion molecules.Our results indicate that hypoglycosylation in PMM2-CDG altered NK cell reactivity against target cells and the expression of CD54 and NKG2D, NKp46 and 2B4 activating receptors during NK cell activation. This suggests a defective control of NK cell killing activity and the overall anti-viral immune response in PMM2-CDG patients. The present

  10. Natural Killer Cell Receptors and Cytotoxic Activity in Phosphomannomutase 2 Deficiency (PMM2-CDG)

    Science.gov (United States)

    García-López, Roberto; de la Morena-Barrio, María Eugenia; Alsina, Laia; Pérez-Dueñas, Belén; Jaeken, Jaak; Serrano, Mercedes; Casado, Mercedes; Hernández-Caselles, Trinidad

    2016-01-01

    Background PMM2-CDG is the most common N-glycosylation defect and shows an increased risk of recurrent and/or severe, sometimes fatal, infections in early life. We hypothesized that natural killer (NK) cells, as important mediators of the immune response against microbial pathogens and regulators of adaptive immunity, might be affected in this genetic disorder. Objective To evaluate possible defects on PMM2-CDG NK peripheral blood cell number, killing activity and expression of membrane receptors. Methods We studied fresh and activated NK cells from twelve PMM2-CDG cells. The number and expression of lymphoid surface receptors were studied by flow cytometry. The NK responsiveness (frequency of degranulated NK cells) and killing activity against K562 target cells was determined in the NK cytotoxicity assay. Results We found an increase of blood NK cells in three patients with a severe phenotype. Two of them, who had suffered from moderate/severe viral infections during their first year of life, also had reduced T lymphocyte numbers. Patient activated NK cells showed increased expression of CD54 adhesion molecule and NKG2D and NKp46 activating receptors. NKp46 and 2B4 expression was inversely correlated with the expression of NKG2D in activated PMM2-CDG cells. Maximal NK activity against K562 target cells was similar in control and PMM2-CDG cells. Interestingly, the NK cell responsiveness was higher in patient cells. NKG2D and specially CD54 increased surface expression significantly correlated with the increased NK cell cytolytic activity according to the modulation of the killer activity by expression of triggering receptors and adhesion molecules. Conclusions Our results indicate that hypoglycosylation in PMM2-CDG altered NK cell reactivity against target cells and the expression of CD54 and NKG2D, NKp46 and 2B4 activating receptors during NK cell activation. This suggests a defective control of NK cell killing activity and the overall anti-viral immune response

  11. Common structural basis for constitutive activity of the ghrelin receptor family

    DEFF Research Database (Denmark)

    Holst, Birgitte; Holliday, Nicholas D; Bach, Anders

    2004-01-01

    -independent signaling activity. The structurally homologous motilin receptor served as a constitutively silent control; upon agonist stimulation, however, it signaled with a similar efficacy to the three related receptors. The constitutive activity of the ghrelin receptor and of neurotensin receptor 2 through the G...... demonstrated that the epitope-tagged ghrelin receptor was constitutively internalized but could be trapped at the cell surface by an inverse agonist, whereas GPR39 remained at the cell surface. Mutational analysis showed that the constitutive activity of both the ghrelin receptor and GPR39 could systematically...

  12. Dual ligand/receptor interactions activate urothelial defenses against uropathogenic E. coli.

    Science.gov (United States)

    Liu, Yan; Mémet, Sylvie; Saban, Ricardo; Kong, Xiangpeng; Aprikian, Pavel; Sokurenko, Evgeni; Sun, Tung-Tien; Wu, Xue-Ru

    2015-11-09

    During urinary tract infection (UTI), the second most common bacterial infection, dynamic interactions take place between uropathogenic E. coli (UPEC) and host urothelial cells. While significant strides have been made in the identification of the virulence factors of UPEC, our understanding of how the urothelial cells mobilize innate defenses against the invading UPEC remains rudimentary. Here we show that mouse urothelium responds to the adhesion of type 1-fimbriated UPEC by rapidly activating the canonical NF-κB selectively in terminally differentiated, superficial (umbrella) cells. This activation depends on a dual ligand/receptor system, one between FimH adhesin and uroplakin Ia and another between lipopolysaccharide and Toll-like receptor 4. When activated, all the nuclei (up to 11) of a multinucleated umbrella cell are affected, leading to significant amplification of proinflammatory signals. Intermediate and basal cells of the urothelium undergo NF-κB activation only if the umbrella cells are detached or if the UPEC persistently express type 1-fimbriae. Inhibition of NF-κB prevents the urothelium from clearing the intracellular bacterial communities, leading to prolonged bladder colonization by UPEC. Based on these data, we propose a model of dual ligand/receptor system in innate urothelial defenses against UPEC.

  13. Activation profiles of opioid ligands in HEK cells expressing δ opioid receptors

    OpenAIRE

    Clark J; Demirci Hasan; Gharagozlou Parham; Lameh Jelveh

    2002-01-01

    Abstract Background The aim of the present study was to characterize the activation profiles of 15 opioid ligands in transfected human embryonic kidney cells expressing only δ opioid receptors. Activation profiles of most of these ligands at δ opioid receptors had not been previously characterized in vitro. Receptor activation was assessed by measuring the inhibition of forskolin-stimulated cAMP production. Results Naltrexone and nalorphine were classified as antagonists at δ opioid receptor....

  14. Activation of the G protein-coupled estrogen receptor, but not estrogen receptor α or β, rapidly enhances social learning.

    Science.gov (United States)

    Ervin, Kelsy Sharice Jean; Mulvale, Erin; Gallagher, Nicola; Roussel, Véronique; Choleris, Elena

    2015-08-01

    Social learning is a highly adaptive process by which an animal acquires information from a conspecific. While estrogens are known to modulate learning and memory, much of this research focuses on individual learning. Estrogens have been shown to enhance social learning on a long-term time scale, likely via genomic mechanisms. Estrogens have also been shown to affect individual learning on a rapid time scale through cell-signaling cascades, rather than via genomic effects, suggesting they may also rapidly influence social learning. We therefore investigated the effects of 17β-estradiol and involvement of the estrogen receptors (ERs) using the ERα agonist propyl pyrazole triol, the ERβ agonist diarylpropionitrile, and the G protein-coupled ER 1 (GPER1) agonist G1 on the social transmission of food preferences (STFP) task, within a time scale that focused on the rapid effects of estrogens. General ER activation with 17β-estradiol resulted in a modest facilitation of social learning, with mice showing a preference up to 30min of testing. Specific activation of the GPER1 also rapidly enhanced social learning, with mice showing a socially learned preference up to 2h of testing. ERα activation instead shortened the expression of a socially learned food preference, while ERβ activation had little to no effects. Thus, rapid estrogenic modulation of social learning in the STFP may be the outcome of competing action at the three main receptors. Hence, estrogens' rapid effects on social learning likely depend on the specific ERs present in brain regions recruited during social learning.

  15. Opioid receptor agonists may favorably affect bone mechanical properties in rats with estrogen deficiency-induced osteoporosis.

    Science.gov (United States)

    Janas, Aleksandra; Folwarczna, Joanna

    2017-02-01

    The results of epidemiological, clinical, and in vivo and in vitro experimental studies on the effect of opioid analgesics on bone are inconsistent. The aim of the present study was to investigate the effect of morphine (an agonist of opioid receptors), buprenorphine (a partial μ opioid receptor agonist and κ opioid receptor antagonist), and naloxone (an antagonist of opioid receptors) on the skeletal system of female rats in vivo. The experiments were carried out on 3-month-old Wistar rats, divided into two groups: nonovariectomized (intact; NOVX) rats and ovariectomized (OVX) rats. The bilateral ovariectomy was performed 7 days before the start of drug administration. Morphine hydrochloride (20 mg/kg/day s.c.), buprenorphine (0.05 mg/kg/day s.c.), or naloxone hydrochloride dihydrate (2 mg/kg/day s.c.) were administered for 4 weeks to NOVX and OVX rats. In OVX rats, the use of morphine and buprenorphine counteracted the development of osteoporotic changes in the skeletal system induced by estrogen deficiency. Morphine and buprenorphine beneficially affected also the skeletal system of NOVX rats, but the effects were much weaker than those in OVX rats. Naloxone generally did not affect the rat skeletal system. The results confirmed the role of opioid receptors in the regulation of bone remodeling processes and demonstrated, in experimental conditions, that the use of opioid analgesics at moderate doses may exert beneficial effects on the skeletal system, especially in estrogen deficiency.

  16. Phagocytic receptors activate and immune inhibitory receptor SIRPα inhibits phagocytosis through paxillin and cofilin.

    Science.gov (United States)

    Gitik, Miri; Kleinhaus, Rachel; Hadas, Smadar; Reichert, Fanny; Rotshenker, Shlomo

    2014-01-01

    The innate immune function of phagocytosis of apoptotic cells, tissue debris, pathogens, and cancer cells is essential for homeostasis, tissue repair, fighting infection, and combating malignancy. Phagocytosis is carried out in the central nervous system (CNS) by resident microglia and in both CNS and peripheral nervous system by recruited macrophages. While phagocytosis proceeds, bystander healthy cells protect themselves by sending a "do not eat me" message to phagocytes as CD47 on their surface ligates immune inhibitory receptor SIRPα on the surface of phagocytes and SIRPα then produces the signaling which inhibits phagocytosis. This helpful mechanism becomes harmful when tissue debris and unhealthy cells inhibit their own phagocytosis by employing the same mechanism. However, the inhibitory signaling that SIRPα produces has not been fully revealed. We focus here on how SIRPα inhibits the phagocytosis of the tissue debris "degenerated myelin" which hinders repair in axonal injury and neurodegenerative diseases. We tested whether SIRPα inhibits phagocytosis by regulating cytoskeleton function through paxillin and cofilin since (a) the cytoskeleton generates the mechanical forces that drive phagocytosis and (b) both paxillin and cofilin control cytoskeleton function. Paxillin and cofilin were transiently activated in microglia as phagocytosis was activated. In contrast, paxillin and cofilin were continuously activated and phagocytosis augmented in microglia in which SIRPα expression was knocked-down by SIRPα-shRNA. Further, levels of phagocytosis, paxillin activation, and cofilin activation positively correlated with one another. Taken together, these observations suggest a novel mechanism whereby paxillin and cofilin are targeted to control phagocytosis by both the activating signaling that phagocytic receptors produce by promoting the activation of paxillin and cofilin and the inhibiting signaling that immune inhibitory SIRPα produces by promoting the

  17. Phagocytic receptors activate and immune inhibitory receptor SIRPalpha inhibits phagocytosis through paxillin and cofilin

    Directory of Open Access Journals (Sweden)

    Miri eGitik

    2014-04-01

    Full Text Available The innate-immune function of phagocytosis of apoptotic cells, tissue-debris, pathogens and cancer cells is essential for homeostasis, tissue repair, fighting infection and combating malignancy. Phagocytosis is carried out in the CNS by resident microglia and in both CNS and PNS by recruited macrophages. While phagocytosis proceeds, bystander healthy cells protect themselves by sending a do not eat me message to phagocytes as CD47 on their surface ligates immune inhibitory receptor SIRPα on the surface of phagocytes and SIRPα then produces the signaling which inhibits phagocytosis. This helpful mechanism becomes harmful when tissue-debris and unhealthy cells inhibit their own phagocytosis by employing the same mechanism. However, the inhibitory signaling that SIRPα produces has not been fully revealed. We focus here on how SIRPα inhibits the phagocytosis of the tissue-debris degenerated-myelin which hinders repair in axonal injury and neurodegenerative diseases. We tested whether SIRPα inhibits phagocytosis by regulating cytoskeleton function through paxillin and cofilin since (a the cytoskeleton generates the mechanical forces that drive phagocytosis and (b both paxillin and cofilin control cytoskeleton function. Paxillin and cofilin were transiently activated in microglia as phagocytosis was activated. In contrast, paxillin and cofilin were continuously activated and phagocytosis augmented in microglia in which SIRPα expression was knocked-down by SIRPα-shRNA. Further, levels of phagocytosis, paxillin activation and cofilin activation positively correlated with one another. Taken together, these observations suggest a novel mechanism whereby paxillin and cofilin are targeted to control phagocytosis by both the activating signaling that phagocytic receptors produce by promoting the activation of paxillin and cofilin and the inhibiting signaling that immune inhibitory SIRPα produces by promoting the inactivation of paxillin and cofilin.

  18. Selective serotonin receptor stimulation of the medial nucleus accumbens differentially affects appetitive motivation for food on a progressive ratio schedule of reinforcement.

    Science.gov (United States)

    Pratt, Wayne E; Schall, Megan A; Choi, Eugene

    2012-03-09

    Previously, we reported that stimulation of selective serotonin (5-HT) receptor subtypes in the nucleus accumbens shell differentially affected consumption of freely available food. Specifically, activation of 5-HT(6) receptors caused a dose-dependent increase in food intake, while the stimulation of 5-HT(1/7) receptor subtypes decreased feeding [34]. The current experiments tested whether similar pharmacological activation of nucleus accumbens serotonin receptors would also affect appetitive motivation, as measured by the amount of effort non-deprived rats exerted to earn sugar reinforcement. Rats were trained to lever press for sugar pellets on a progressive ratio 2 schedule of reinforcement. Across multiple treatment days, three separate groups (N=8-10) received bilateral infusions of the 5-HT(6) agonist EMD 386088 (at 0.0, 1.0 and 4.0 μg/0.5 μl/side), the 5-HT(1/7) agonist 5-CT (at 0, 0.5, 1.0, or 4.0 μg/0.5 μl/side), or the 5-HT(2C) agonist RO 60-0175 fumarate (at 0, 2.0, or 5.0 μg/0.5 μl/side) into the anterior medial nucleus accumbens prior to a 1-h progressive ratio session. Stimulation of 5-HT(6) receptors caused a dose-dependent increase in motivation as assessed by break point, reinforcers earned, and total active lever presses. Stimulation of 5-HT(1/7) receptors increased lever pressing at the 0.5 μg dose of 5-CT, but inhibited lever presses and break point at 4.0 μg/side. Injection of the 5-HT(2C) agonist had no effect on motivation within the task. Collectively, these experiments suggest that, in addition to their role in modulating food consumption, nucleus accumbens 5-HT(6) and 5-HT(1/7) receptors also differentially regulate the appetitive components of food-directed motivation.

  19. Amyloid β-protein differentially affects NMDA receptor- and GABAA receptor-mediated currents in rat hippocampal CA1 neurons

    Institute of Scientific and Technical Information of China (English)

    Junfang Zhang; Lei Hou; Xiuping Gao; Fen Guo; Wei Jing; Jinshun Qi; Jiantian Qiao

    2009-01-01

    Although the aggregated amyloid β-protein (Aβ) in senile plaques is one of the key neuropathological features of Alzheimer's disease (AD), soluble forms of Aβ also interfere with synaptic plasticity at the early stage of AD. The suppressive action of acute application of Aβ on hippocampal long-term potentiation (LTP) has been reported widely, whereas the mechanism underlying the effects of Aβ is still mostly unknown. The present study, using the whole-cell patch clamp technique, investigated the effects of Aβ fragments (Aβ25-35 and Aβ31-35) on the LTP induction-related postsynaptic ligand-gated channel currents in isolated hippocampal CA1 neurons. The results showed a rapid but opposite action of both peptides on excitatory and inhibitory receptor currents. Glutamate application-induced currents were suppressed by A β25-35 in a dose-dependent manner, and further N-methyl-I>aspartate (NMDA) receptor-mediated currents were selec-tively inhibited. In contrast, pretreatment with Aβ fragments potentiated γ-aminobutyric acid (GABA)-induced whole-cell currents. As a control, Aβ35-31 the reversed sequence of Aβ35-31 showed no effect on the currents induced by glutamate, NMDA or GABA. These results may partly explain the impaired effects of Aβ on hippocampal LTP, and suggest that the functional down-regulation of N M DA receptors and up-regulation of GABAA receptors may play an important role in remodeling the hippocampal synaptic plasticity in early AD.

  20. Stimulation of cannabinoid receptor 2 (CB2 suppresses microglial activation

    Directory of Open Access Journals (Sweden)

    Fernandez Francisco

    2005-12-01

    Full Text Available Abstract Background Activated microglial cells have been implicated in a number of neurodegenerative disorders, including Alzheimer's disease (AD, multiple sclerosis (MS, and HIV dementia. It is well known that inflammatory mediators such as nitric oxide (NO, cytokines, and chemokines play an important role in microglial cell-associated neuron cell damage. Our previous studies have shown that CD40 signaling is involved in pathological activation of microglial cells. Many data reveal that cannabinoids mediate suppression of inflammation in vitro and in vivo through stimulation of cannabinoid receptor 2 (CB2. Methods In this study, we investigated the effects of a cannabinoid agonist on CD40 expression and function by cultured microglial cells activated by IFN-γ using RT-PCR, Western immunoblotting, flow cytometry, and anti-CB2 small interfering RNA (siRNA analyses. Furthermore, we examined if the stimulation of CB2 could modulate the capacity of microglial cells to phagocytise Aβ1–42 peptide using a phagocytosis assay. Results We found that the selective stimulation of cannabinoid receptor CB2 by JWH-015 suppressed IFN-γ-induced CD40 expression. In addition, this CB2 agonist markedly inhibited IFN-γ-induced phosphorylation of JAK/STAT1. Further, this stimulation was also able to suppress microglial TNF-α and nitric oxide production induced either by IFN-γ or Aβ peptide challenge in the presence of CD40 ligation. Finally, we showed that CB2 activation by JWH-015 markedly attenuated CD40-mediated inhibition of microglial phagocytosis of Aβ1–42 peptide. Taken together, these results provide mechanistic insight into beneficial effects provided by cannabinoid receptor CB2 modulation in neurodegenerative diseases, particularly AD.

  1. Facilitation of neocortical presynaptic terminal development by NMDA receptor activation

    Directory of Open Access Journals (Sweden)

    Sceniak Michael P

    2012-02-01

    Full Text Available Abstract Background Neocortical circuits are established through the formation of synapses between cortical neurons, but the molecular mechanisms of synapse formation are only beginning to be understood. The mechanisms that control synaptic vesicle (SV and active zone (AZ protein assembly at developing presynaptic terminals have not yet been defined. Similarly, the role of glutamate receptor activation in control of presynaptic development remains unclear. Results Here, we use confocal imaging to demonstrate that NMDA receptor (NMDAR activation regulates accumulation of multiple SV and AZ proteins at nascent presynaptic terminals of visual cortical neurons. NMDAR-dependent regulation of presynaptic assembly occurs even at synapses that lack postsynaptic NMDARs. We also provide evidence that this control of presynaptic terminal development is independent of glia. Conclusions Based on these data, we propose a novel NMDAR-dependent mechanism for control of presynaptic terminal development in excitatory neocortical neurons. Control of presynaptic development by NMDARs could ultimately contribute to activity-dependent development of cortical receptive fields.

  2. 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

  3. 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

  4. Peroxisome proliferator-activated receptor delta activation leads to increased transintestinal cholesterol efflux

    NARCIS (Netherlands)

    Vrins, Carlos L. J.; van der Velde, Astrid E.; van den Oever, Karin; Levels, Johannes H. M.; Huet, Stephane; Elferink, Ronald P. J. Oude; Kuipers, Folkert; Groen, Albert K.

    2009-01-01

    Peroxisome proliferator-activated receptor delta (PPAR delta) is involved in regulation of energy homeostasis. Activation of PPAR delta markedly increases fecal neutral sterol secretion, the last step in reverse cholesterol transport. This phenomenon can neither be explained by increased hepatobilia

  5. Sulfonylureas and glinides exhibit peroxisome proliferator-activated receptor gamma activity: A combined virtual screening and biological assay approach

    NARCIS (Netherlands)

    Scarsi, M.; Podvinec, M.; Roth, A.; Hug, H.; Kersten, A.H.; Albrecht, H.; Schwede, T.; Meyer, U.A.; Rucker, C.

    2007-01-01

    Most drugs currently employed in the treatment of type 2 diabetes either target the sulfonylurea receptor stimulating insulin release (sulfonylureas, glinides), or target the peroxisome proliferator-activated receptor (PPAR) improving insulin resistance (thiazolidinediones). Our work shows that sulf

  6. Lack of CB1 receptors increases noradrenaline release in vas deferens without affecting atrial noradrenaline release or cortical acetylcholine release

    OpenAIRE

    Schlicker, Eberhard; Redmer, Agnes; Werner, André; Kathmann, Markus

    2003-01-01

    We studied whether cannabinoid CB1 receptor gene disruption (to yield CB1−/− mice) affects the electrically evoked tritium overflow from vas deferens and atrial pieces preincubated with [3H]-noradrenaline (NA) (‘noradrenaline release') and from cerebral cortex slices preincubated with [3H]-choline (‘acetylcholine release').NA release was higher by 37% in vas deferens from CB1−/− mice than in vas deferens from CB1+/+ mice. The cannabinoid receptor agonist WIN 55,212-2 inhibited, and the CB1 re...

  7. Spinal 5-HT7 receptor activation induces long-lasting phrenic motor facilitation.

    Science.gov (United States)

    Hoffman, M S; Mitchell, G S

    2011-03-15

    Acute intermittent hypoxia elicits a form of serotonin-dependent respiratory plasticity known as phrenic long term facilitation (pLTF). Episodic spinal serotonin-2 (5-HT2) receptor activation on or near phrenic motor neurons is necessary for pLTF. A hallmark of pLTF is the requirement for serotonin-dependent synthesis of brain-derived neurotrophic factor (BDNF), and activation of its high affinity receptor, TrkB. Activation of spinal Gs protein-coupled adenosine 2A receptors (GsPCRs) elicits a unique form of long-lasting phrenic motor facilitation (PMF), but via unique mechanisms (BDNF independent TrkB trans-activation).We hypothesized that other GsPCRs elicit PMF, specifically serotonin-7 (5-HT7) receptors, which are expressed in phrenic motor neurons. Cervical spinal (C4) injections of a selective 5-HT7 receptor agonist, AS-19 (10 μM, 5 μl; 3 × 5 min), in anaesthetized, vagotomized and ventilated male Sprague-Dawley rats elicited long-lasting PMF (>120 min), an effect prevented by pretreatment with a 5-HT7 receptor antagonist (SB 269970; 5mM, 7 μl).GsPCR activation 'trans-activates'TrkB by increasing synthesis of an immature TrkB isoform. Spinal injection of a TrkB inhibitor (k252a) and siRNAs that prevent TrkB (but not BDNF) mRNA translation both blocked 5-HT7 agonist-induced PMF, confirming a requirement for TrkB synthesis and activity. k252a affected late PMF (≥ 90 min) only. Spinal inhibition of the PI3K/AKT pathway blocked 5-HT7 agonist-induced PMF, whereas MEK/ERK inhibition delayed, but did not block, PMF. An understanding of signalling mechanisms giving rise to PMF may guide development of novel therapeutic strategies to treat ventilatory control disorders associated with respiratory insufficiency, such as spinal injury and motor neuron disease.

  8. Methamphetamine Increases Locomotion and Dopamine Transporter Activity in Dopamine D5 Receptor-Deficient Mice

    OpenAIRE

    Seiji Hayashizaki; Shinobu Hirai; Yumi Ito; Yoshiko Honda; Yosefu Arime; Ichiro Sora; Haruo Okado; Tohru Kodama; Masahiko Takada

    2013-01-01

    Dopamine regulates the psychomotor stimulant activities of amphetamine-like substances in the brain. The effects of dopamine are mediated through five known dopamine receptor subtypes in mammals. The functional relevance of D5 dopamine receptors in the central nervous system is not well understood. To determine the functional relevance of D5 dopamine receptors, we created D5 dopamine receptor-deficient mice and then used these mice to assess the roles of D5 dopamine receptors in the behaviora...

  9. Gene expression changes in rat prostate after activation or blocking of the androgen and estrogen receptor

    DEFF Research Database (Denmark)

    Nellemann, Christine Lydia; Dalgaard, Majken; Holst, Bjørn;

    2005-01-01

    Several endpoints of different molecular complexity were studied in the Hershberger assay in order to evaluate the specificity and suitability of this test as a broad screening model. Androgen and estrogen receptors were activated or blocked, and expression of typical estrogen- or androgen...... and the anti-estrogen, ICI 182780, only affected ODC expression. Therefore, estrogenic or anti-estrogenic compounds would not be expected to seriously affect the outcome of a Hershberger test. However, EB given alone to castrated rats resulted in various effects. EB increased seminal vesicle weight, an effect...... reversed by ICI 182780, and affected TRPM-2, PBP C3, ODC, IGF-1, AR, and ERa mRNA levels. AR expression in the prostate seemed to be under regulation of both estrogens and androgens, as ICI 182780 inhibited the testosterone-induced AR expression, and flutamide inhibited the EB-induced AR expression...

  10. FATTY ACIDS MODULATE TOLL-LIKE RECEPTOR 4 ACTIVATION THROUGH REGULATION OF RECEPTOR DIMERIZATION AND RECRUITMENT INTO LIPID RAFTS

    Science.gov (United States)

    The saturated fatty acids acylated on Lipid A of lipopolysaccharide (LPS) or bacterial lipoproteins play critical roles in ligand recognition and receptor activation for Toll-like Receptor 4 (TLR4) and TLR2. The results from our previous studies (J Biol Chem 2003, 2004) demonstrated that saturated ...

  11. Leptin Receptor Gene Polymorphism may Affect Subclinical Atherosclerosis in Patients with Acromegaly

    Science.gov (United States)

    Turgut, Sebahat; Topsakal, Senay; Ata, Melek Tunç; Herek, Duygu; Akın, Fulya; Özkan, Şeyma; Turgut, Günfer

    2016-01-01

    Background: Acromegaly is associated with increased morbidity and mortality related to cardiovascular diseases. Leptin (LEP) and Leptin Receptor (LEPR) gene polymorphisms can increase cardiovascular risks. The aim of this study was to investigate association between the frequencies of LEP and LEPR gene polymorphisms and subclinical atherosclerosis in acromegalic patients. Methods: Forty-four acromegalic patients and 30 controls were admitted to study. The polymorphisms were identified by using polymerase chain reaction from peripheral blood samples. The levels of systolic and diastolic blood pressure, BMI, fasting plasma glucose, fasting insulin, IGF-I, GH, IGFBP3, leptin, triglyceride, carotid Intima Media Thickness (cIMT) and HDL and LDL cholesterol concentrations were evaluated. Results: There was statistically significant difference between the LEPR genotypes of acromegalic patients (GG 11.4%, GA 52.3%, and AA 36.4%) and controls (GG 33.3%, GA 50%, and AA 16.7%) although their LEP genotype distribution was similar. In addition, the prevalence of the LEPR gene G and A alleles was significantly different between patients and controls. No significant difference was found among the G(-2548) A leptin genotypes of groups in terms of the clinical parameters. cIMT significantly increased homozygote LEPR GG genotype group compared to AA subjects in patients. But the other parameters were not different between LEPR genotypes groups of patients and controls. Conclusion: It can be said that the LEPR gene polymorphism may affect cIMT in patients. The reason is that LEPR GG genotype carriers may have more risk than other genotypes in the development of subclinical atherosclerosis in acromegaly. PMID:27563428

  12. Characterization of human endothelial cell urokinase-type plasminogen activator receptor protein and messenger RNA

    DEFF Research Database (Denmark)

    Barnathan, E S; Kuo, A; Karikó, K

    1990-01-01

    Human umbilical vein endothelial cells in culture (HUVEC) express receptors for urokinase-type plasminogen activators (u-PA). The immunochemical nature of this receptor and its relationship to u-PA receptors expressed by other cell types is unknown. Cross-linking active site-blocked u-PA to HUVEC...

  13. Activation of μ-opioid receptor and Toll-like receptor 4 by plasma from morphine-treated mice.

    Science.gov (United States)

    Xie, Nan; Gomes, Fabio P; Deora, Vandana; Gregory, Kye; Vithanage, Tharindu; Nassar, Zeyad D; Cabot, Peter J; Sturgess, David; Shaw, Paul N; Parat, Marie-Odile

    2017-03-01

    In this study, we quantified the ability of opioids present in biological samples to activate the μ-opioid receptor and TLR4 using cell-based assays. Each assay was standardised, in the presence of plasma, using morphine, its μ receptor-active metabolite morphine-6 glucuronide (M6G) and its μ receptor-inactive, but TLR4-active metabolite morphine-3 glucuronide (M3G). Specificity was verified using antagonists. Morphine- and M6G-spiked plasma samples exhibited μ receptor activation, which M3G-spiked plasma lacked. In contrast, M3G showed moderate but consistent activation of TLR-4. Plasma samples were collected at a number of time points from mice administered morphine (1 or 10mg/kg every 12h for 3days) or saline. Morphine administration led to intermittent μ receptor activation, reversed by μ receptor antagonists, and to TRL4 activation at time points where M3G is measured in plasma. Interestingly, this protocol of morphine administration also led to TLR4-independent NF-κB activation, at time points where M3G was not detected, presumably via elevation of circulating cytokines including, but not limited to, TNFα. Circulating TNFα was increased after three days of morphine administration, and TNFα mRNA elevated in the spleen of morphine-treated mice.

  14. Dopamine receptor activation increases glial cell line-derived neurotrophic factor in experimental stroke.

    Science.gov (United States)

    Kuric, Enida; Wieloch, Tadeusz; Ruscher, Karsten

    2013-09-01

    Treatment with levodopa enhances functional recovery after experimental stroke but its mechanisms of action are elusive. Reactive astrocytes in the ischemic hemisphere are involved in mechanisms promoting recovery and also express dopamine 1 (D1) and dopamine 2 (D2) receptors. Here we investigated if the activation of astrocytic dopamine receptors (D1 and D2) regulates the expression of glial cell line-derived neurotrophic factor (GDNF) after combined in vitro hypoxia/aglycemia (H/A) and studied the expression of GDNF in the ischemic brain after treatment with levodopa/benserazide following transient occlusion of the middle cerebral artery (tMCAO) in the rat. Twenty-four hours after H/A, GDNF levels were upregulated in exposed astrocytes compared to normoxic control cultures and further elevated by the addition of the selective D1 receptor agonist (R)-(+)-SKF-38393 hydrochloride while D1 receptor antagonism by R(+)-SCH-23390 hydrochloride significantly reduced GDNF. No effect on GDNF levels was observed by the application of the D2 receptor agonist R(-)-2,10,11-trihydroxy-N-propyl-noraporphine hydrobromide hydrate or S-(-)-eticlopride hydrochloride (D2 receptor antagonist). After tMCAO, GDNF was upregulated in D1 expressing reactive astrocytes in the peri-infarct area. In addition, treatment with levodopa/benserazide significantly increased GDNF levels in the infarct core and peri-infarct area after tMCAO without affecting the expression of glial fibrillar acidic protein (GFAP), an intermediate filament and marker of reactive gliosis. After stroke, GDNF levels increase in the ischemic hemisphere in rats treated with levodopa, implicating GDNF in the mechanisms of tissue reorganization and plasticity and in l-DOPA enhanced recovery of lost brain function. Our results support levodopa treatment as a potential recovery enhancing therapy in stroke patients.

  15. Cannabinoid receptor-2 selective antagonist negatively regulates receptor activator of nuclear factor kappa B ligand mediated osteoclastogenesis

    Institute of Scientific and Technical Information of China (English)

    GENG De-chun; XU Yao-zeng; YANG Hui-lin; ZHU Guang-ming; WANG Xian-bin; ZHU Xue-song

    2011-01-01

    Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL)induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA)was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK),phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of >100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.

  16. Activation of a Temporal Memory in Purkinje Cells by the mGluR7 Receptor

    Directory of Open Access Journals (Sweden)

    Fredrik Johansson

    2015-12-01

    Full Text Available Cerebellar Purkinje cells can learn to respond to a conditioned stimulus with an adaptively timed pause in firing. This response was usually ascribed to long-term depression of parallel fiber to Purkinje cell synapses but has recently been shown to be due to a previously unknown form of learning involving an intrinsic cellular timing mechanism. Here, we investigate how these responses are elicited. They are resistant to blockade of GABAergic inhibition, suggesting that they are caused by glutamate release rather than by a changed balance between GABA and glutamate. We show that the responses are abolished by antagonists of the mGlu7 receptor but not significantly affected by other glutamate antagonists. These results support the existence of a distinct learning mechanism, different from changes in synaptic strength. They also demonstrate in vivo post-synaptic inhibition mediated by glutamate and show that the mGlu7 receptor is involved in activating intrinsic temporal memory.

  17. Protease activated receptor-2 contributes to heart failure.

    Directory of Open Access Journals (Sweden)

    Silvio Antoniak

    Full Text Available Heart failure is a major clinical problem worldwide. Previous studies have demonstrated an important role for G protein-coupled receptors, including protease-activated receptors (PARs, in the pathology of heart hypertrophy and failure. Activation of PAR-2 on cardiomyocytes has been shown to induce hypertrophic growth in vitro. PAR-2 also contributes to myocardial infarction and heart remodeling after ischemia/reperfusion injury. In this study, we found that PAR-2 induced hypertrophic growth of cultured rat neonatal cardiomyocytes in a MEK1/2 and p38 dependent manner. In addition, PAR-2 activation on mouse cardiomyocytes increased expression of the pro-fibrotic chemokine MCP-1. Furthermore, cardiomyocyte-specific overexpression of PAR-2 in mice induced heart hypertrophy, cardiac fibrosis, inflammation and heart failure. Finally, in a mouse model of myocardial infarction induced by permanent ligation of the left anterior descending coronary artery, PAR-2 deficiency attenuated heart remodeling and improved heart function independently of its contribution to the size of the initial infarct. Taken together, our data indicate that PAR-2 signaling contributes to the pathogenesis of hypertrophy and heart failure.

  18. Lymphotropic Virions Affect Chemokine Receptor-Mediated Neural Signaling and Apoptosis: Implications for Human Immunodeficiency Virus Type 1-Associated Dementia

    Science.gov (United States)

    Zheng, Jialin; Ghorpade, Anuja; Niemann, Douglas; Cotter, Robin L.; Thylin, Michael R.; Epstein, Leon; Swartz, Jennifer M.; Shepard, Robin B.; Liu, Xiaojuan; Nukuna, Adeline; Gendelman, Howard E.

    1999-01-01

    Chemokine receptors pivotal for human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes and macrophages (CCR3, CCR5, and CXCR4) are expressed on neural cells (microglia, astrocytes, and/or neurons). It is these cells which are damaged during progressive HIV-1 infection of the central nervous system. We theorize that viral coreceptors could effect neural cell damage during HIV-1-associated dementia (HAD) without simultaneously affecting viral replication. To these ends, we studied the ability of diverse viral strains to affect intracellular signaling and apoptosis of neurons, astrocytes, and monocyte-derived macrophages. Inhibition of cyclic AMP, activation of inositol 1,4,5-trisphosphate, and apoptosis were induced by diverse HIV-1 strains, principally in neurons. Virions from T-cell-tropic (T-tropic) strains (MN, IIIB, and Lai) produced the most significant alterations in signaling of neurons and astrocytes. The HIV-1 envelope glycoprotein, gp120, induced markedly less neural damage than purified virions. Macrophage-tropic (M-tropic) strains (ADA, JR-FL, Bal, MS-CSF, and DJV) produced the least neural damage, while 89.6, a dual-tropic HIV-1 strain, elicited intermediate neural cell damage. All T-tropic strain-mediated neuronal impairments were blocked by the CXCR4 antibody, 12G5. In contrast, the M-tropic strains were only partially blocked by 12G5. CXCR4-mediated neuronal apoptosis was confirmed in pure populations of rat cerebellar granule neurons and was blocked by HA1004, an inhibitor of calcium/calmodulin-dependent protein kinase II, protein kinase A, and protein kinase C. Taken together, these results suggest that progeny HIV-1 virions can influence neuronal signal transduction and apoptosis. This process occurs, in part, through CXCR4 and is independent of CD4 binding. T-tropic viruses that traffic in and out of the brain during progressive HIV-1 disease may play an important role in HAD neuropathogenesis. PMID:10482576

  19. Effect of highly bioaccumulated polychlorinated biphenyl congeners on estrogen and androgen receptor activity

    DEFF Research Database (Denmark)

    Bonefeld-Jørgensen, E.C.; Andersen, H. R.; Rasmussen, T.H.;

    2001-01-01

    Polychlorinated biphenyls (PCBs) are ubiquitous environmental persistent contaminants giving rise to potential health hazard. Some PCBs exert dioxin-like activities mediated through the aryl hydrocarbon receptor. Although reports on interaction with other nuclear receptors are sparce, some...

  20. Oxidatively fragmented phosphatidylcholines activate human neutrophils through the receptor for platelet-activating factor.

    Science.gov (United States)

    Smiley, P L; Stremler, K E; Prescott, S M; Zimmerman, G A; McIntyre, T M

    1991-06-15

    Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) activates neutrophils (polymorphonuclear leukocytes, PMN) through a receptor that specifically recognizes short sn-2 residues. We oxidized synthetic [2-arachidonoyl]phosphatidylcholine to fragment and shorten the sn-2 residue, and then examined the phospholipid products for the ability to stimulate PMN. 1-Palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine was fragmented by ozonolysis to 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine. This phospholipid activated human neutrophils at submicromolar concentrations, and is effects were inhibited by specific PAF receptor antagonists WEB2086, L659,989, and CV3988. 1-Palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine next was fragmented by an uncontrolled free radical-catalyzed reaction: it was treated with soybean lipoxygenase to form its sn-2 15-hydroperoxy derivative (which did not activate neutrophils) and then allowed to oxidize under air. The secondary oxidation resulted in the formation of numerous fragmented phospholipids (Stremler, K. E., Stafforini, D. M., Prescott, S. M., and McIntyre, T. M. (1991) J. Biol. Chem. 266, 11095-11103), some of which activated PMN. Hydrolysis of sn-2 residues with phospholipase A2 destroyed biologic activity, as did hydrolysis with PAF acetylhydrolase. PAF acetylhydrolase is specific for short or intermediate length sn-2 residues and does not hydrolyze the starting material (Stremler, K. E., Stafforini, D. M., Prescott, S. M., and McIntyre, T. M. (1991) J. Biol. Chem. 266, 11095-11103). Neutrophil activation was completely blocked by L659,989, a specific PAF receptor antagonist. We conclude that diacylphosphatidylcholines containing an sn-2 polyunsaturated fatty acyl residue can be oxidatively fragmented to species with sn-2 residues short enough to activate the PAF receptor of neutrophils. This suggests a new mechanism for the appearance of biologically active phospholipids, and shows

  1. Frontolimbic serotonin 2A receptor binding in healthy subjects is associated with personality risk factors for affective disorder

    DEFF Research Database (Denmark)

    Frokjaer, Vibe G.; Mortensen, Erik L.; Nielsen, Finn Årup

    2008-01-01

    Background: Serotonergic dysfunction has been associated with affective disorders. High trait neuroticism, as measured on personality inventories, is a risk factor for major depression. In this study we investigated whether neuroticism is associated with serotonin 2A receptor binding in brain....... The correlation between the neuroticism score and frontolimbic serotonin 2A receptor binding was evaluated by multiple linear regression analysis with adjustment for age and gender. Results: Neuroticism correlated positively with frontolimbic serotonin 2A receptor binding [r(79) = .24, p = .028]. Post hoc...... analysis of the contributions from the six constituent traits of neuroticism showed that the correlation was primarily driven by two of them: vulnerability and anxiety. Indeed, vulnerability, defined as a person's difficulties in coping with stress, displayed the strongest positive correlation, which...

  2. The glucagon-like peptide 1 receptor agonist enhances intrinsic peroxisome proliferator-activated receptor γ activity in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Onuma, Hirohisa; Inukai, Kouichi, E-mail: kinukai@ks.kyorin-u.ac.jp; Kitahara, Atsuko; Moriya, Rie; Nishida, Susumu; Tanaka, Toshiaki; Katsuta, Hidenori; Takahashi, Kazuto; Sumitani, Yoshikazu; Hosaka, Toshio; Ishida, Hitoshi

    2014-08-22

    Highlights: • PPARγ activation was involved in the GLP-1-mediated anti-inflammatory action. • Exendin-4 enhanced endogenous PPARγ transcriptional activity in HUVECs. • H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement. • The anti-inflammatory effects of GLP-1 may be explained by PPARγ activation. - Abstract: Recent studies have suggested glucagon-like peptide-1 (GLP-1) signaling to exert anti-inflammatory effects on endothelial cells, although the precise underlying mechanism remains to be elucidated. In the present study, we investigated whether PPARγ activation is involved in the GLP-1-mediated anti-inflammatory action on endothelial cells. When we treated HUVEC cells with 0.2 ng/ml exendin-4, a GLP-1 receptor agonist, endogenous PPARγ transcriptional activity was significantly elevated, by approximately 20%, as compared with control cells. The maximum PPARγ activity enhancing effect of exendin-4 was observed 12 h after the initiation of incubation with exendin-4. As H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement, the signaling downstream from GLP-1 cross-talk must have been involved in PPARγ activation. In conclusion, our results suggest that GLP-1 has the potential to induce PPARγ activity, partially explaining the anti-inflammatory effects of GLP-1 on endothelial cells. Cross-talk between GLP-1 signaling and PPARγ activation would have major impacts on treatments for patients at high risk for cardiovascular disease.

  3. Thiazide diuretics affect osteocalcin production in human osteoblasts at the transcription level without affecting vitamin D3 receptors.

    Science.gov (United States)

    Lajeunesse, D; Delalandre, A; Guggino, S E

    2000-05-01

    Besides their natriuretic and calciuretic effect, thiazide diuretics have been shown to decrease bone loss rate and improve bone mineral density. Clinical evidence suggests a specific role of thiazides on osteoblasts, because it reduces serum osteocalcin (OC), an osteoblast-specific protein, yet the mechanisms implicated are unknown. We therefore investigated the role of hydrochlorothiazide (HCTZ) on OC production by the human osteoblast-like cell line MG-63. HCTZ dose-dependently (1-100 microM) inhibited 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-induced OC release by these cells (maximal effect, -40-50% and p ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) only partly prevented the inhibitory effect of the diuretic on OC secretion (maximal effect, -22.5+/-6.9%), suggesting that thiazide-dependent Ca2+ influx is not sufficient to elicit the inhibition of OC secretion. Because OC production is strictly dependent on the presence of 1,25(OH)2D3 in human osteoblasts, we next evaluated the possible role of HCTZ on vitamin D3 receptors (VDR) at the mRNA and protein levels. Both Northern and Western blot analyses showed no effect of HCTZ (1-100 microM) on VDR levels. The presence of EGTA in the culture media reduced slightly the VDR mRNA levels under basal condition but this was not modified in the presence of increasing levels of HCTZ. The OC gene promoter also is under the control of transcription factors such as Yin Yang 1 (YY1) and cFOS. Western blot analysis revealed no changes in YY1 levels in response to HCTZ either in the presence or in the absence of 0.5 mM EGTA in the culture media. In contrast, HCTZ induced a dose-dependent increase in cFOS levels (p production by HCTZ could explain its preventive role in bone loss rate.

  4. Could the 5-HT1B receptor inverse agonism affect learning consolidation?

    Science.gov (United States)

    Meneses, A

    2001-03-01

    Diverse evidence indicates that, the 5-HT system might play a role in learning and memory, since it occurs in brain areas mediating such processes and 5-HT drugs modulate them. Hence in this work, in order to explore further 5-HT involvement on learning and memory 5-HT1B receptors' role is investigated. Evidence indicates that SB-224289 (a 5-HT1B receptor inverse agonist) post-training injection facilitated learning consolidation in an associative autoshaping learning task, this effect was partially reversed by GR 127935 (a 5-HT1B/1D receptor antagonist), but unaffected by MDL 100907 (a 5-HT2A receptor antagonist) or ketanserin (a 5-HT1D/2A/7 receptor antagonist) at low doses. Moreover, SB-224289 antagonized the learning deficit produced by TFMPP (a 5-HT1A/1B/1D/2A/2C receptor agonist), GR 46611 (a 5-HT1A/1B/1D receptor agonist), mCPP (a 5-HT2A/2C/3/7 receptor agonist/antagonist) or GR 127935 (at low dose). SB-224289 did not alter the 8-OH-DPAT (a 5-HT1A/7 receptor agonist) learning facilitatory effect. SB-224289 eliminated the deficit learning produced by the anticholinergic muscarinic scopolamine or the glutamatergic antagonist dizocilpine. Administration of both, GR 127935 (5mg/kg) plus ketanserin (0.01 mg/kg) did not modify learning consolidation; nevertheless, when ketanserin dose was increased (0.1-1.0mg/kg) and SB-224289 dose was maintained constant, a learning facilitation effect was observed. Notably, SB-224289 at 1.0mg/kg potentiated a subeffective dose of the 5-HT1B/1D receptor agonist/antagonist mixed GR 127935, which facilitated learning consolidation and this effect was abolished by ketanserin at a higher dose. Collectively, the data confirm and extend the earlier findings with GR 127935 and the effects of non-selective 5-HT(1B) receptor agonists. Clearly 5-HT1B agonists induced a learning deficit which can be reversed with SB-224289. Perhaps more importantly, SB-224289 enhances learning consolidation when given alone and can reverse the deficits

  5. Flavaglines Stimulate Transient Receptor Potential Melastatin Type 6 (TRPM6) Channel Activity.

    Science.gov (United States)

    Blanchard, Maxime G; de Baaij, Jeroen H F; Verkaart, Sjoerd A J; Lameris, Anke L; Basmadjian, Christine; Zhao, Qian; Désaubry, Laurent; Bindels, René J M; Hoenderop, Joost G J

    2015-01-01

    Magnesium (Mg2+) is essential for enzymatic activity, brain function and muscle contraction. Blood Mg2+ concentrations are tightly regulated between 0.7 and 1.1 mM by Mg2+ (re)absorption in kidney and intestine. The apical entry of Mg2+ in (re)absorbing epithelial cells is mediated by the transient receptor potential melastatin type 6 (TRPM6) ion channel. Here, flavaglines are described as a novel class of stimulatory compounds for TRPM6 activity. Flavaglines are a group of natural and synthetic compounds that target the ubiquitously expressed prohibitins and thereby affect cellular signaling. By whole-cell patch clamp analyses, it was demonstrated that nanomolar concentrations of flavaglines increases TRPM6 activity by ∼2 fold. The stimulatory effects were dependent on the presence of the alpha-kinase domain of TRPM6, but did not require its phosphotransferase activity. Interestingly, it was observed that two natural occurring TRPM6 mutants with impaired insulin-sensitivity, TRPM6-p.Val1393Ile and TRPM6-p.Lys1584Glu, are not sensitive to flavagline stimulation. In conclusion, we have identified flavaglines as potent activators of TRPM6 activity. Our results suggest that flavaglines stimulate TRPM6 via the insulin receptor signaling pathway.

  6. Flavaglines Stimulate Transient Receptor Potential Melastatin Type 6 (TRPM6 Channel Activity.

    Directory of Open Access Journals (Sweden)

    Maxime G Blanchard

    Full Text Available Magnesium (Mg2+ is essential for enzymatic activity, brain function and muscle contraction. Blood Mg2+ concentrations are tightly regulated between 0.7 and 1.1 mM by Mg2+ (reabsorption in kidney and intestine. The apical entry of Mg2+ in (reabsorbing epithelial cells is mediated by the transient receptor potential melastatin type 6 (TRPM6 ion channel. Here, flavaglines are described as a novel class of stimulatory compounds for TRPM6 activity. Flavaglines are a group of natural and synthetic compounds that target the ubiquitously expressed prohibitins and thereby affect cellular signaling. By whole-cell patch clamp analyses, it was demonstrated that nanomolar concentrations of flavaglines increases TRPM6 activity by ∼2 fold. The stimulatory effects were dependent on the presence of the alpha-kinase domain of TRPM6, but did not require its phosphotransferase activity. Interestingly, it was observed that two natural occurring TRPM6 mutants with impaired insulin-sensitivity, TRPM6-p.Val1393Ile and TRPM6-p.Lys1584Glu, are not sensitive to flavagline stimulation. In conclusion, we have identified flavaglines as potent activators of TRPM6 activity. Our results suggest that flavaglines stimulate TRPM6 via the insulin receptor signaling pathway.

  7. Flavaglines Stimulate Transient Receptor Potential Melastatin Type 6 (TRPM6) Channel Activity

    Science.gov (United States)

    Verkaart, Sjoerd A. J.; Lameris, Anke L.; Basmadjian, Christine; Zhao, Qian; Désaubry, Laurent; Bindels, René J. M.; Hoenderop, Joost G. J.

    2015-01-01

    Magnesium (Mg2+) is essential for enzymatic activity, brain function and muscle contraction. Blood Mg2+ concentrations are tightly regulated between 0.7 and 1.1 mM by Mg2+ (re)absorption in kidney and intestine. The apical entry of Mg2+ in (re)absorbing epithelial cells is mediated by the transient receptor potential melastatin type 6 (TRPM6) ion channel. Here, flavaglines are described as a novel class of stimulatory compounds for TRPM6 activity. Flavaglines are a group of natural and synthetic compounds that target the ubiquitously expressed prohibitins and thereby affect cellular signaling. By whole-cell patch clamp analyses, it was demonstrated that nanomolar concentrations of flavaglines increases TRPM6 activity by ∼2 fold. The stimulatory effects were dependent on the presence of the alpha-kinase domain of TRPM6, but did not require its phosphotransferase activity. Interestingly, it was observed that two natural occurring TRPM6 mutants with impaired insulin-sensitivity, TRPM6-p.Val1393Ile and TRPM6-p.Lys1584Glu, are not sensitive to flavagline stimulation. In conclusion, we have identified flavaglines as potent activators of TRPM6 activity. Our results suggest that flavaglines stimulate TRPM6 via the insulin receptor signaling pathway. PMID:25774985

  8. Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂) activity in rat skeletal muscle.

    Science.gov (United States)

    Philp, Andrew; MacKenzie, Matthew G; Belew, Micah Y; Towler, Mhairi C; Corstorphine, Alan; Papalamprou, Angela; Hardie, D Grahame; Baar, Keith

    2013-01-01

    Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR) coactivator-1α (PGC-1α) and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4): control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]). Gastrocnemius (GTN) muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP) assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E) finished with higher AMPK-α2 activity (147%, pexercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal muscle in response to exercise.

  9. Acetylcholine release in mouse hippocampal CA1 preferentially activates inhibitory-selective interneurons via alpha4 beta2* nicotinic receptor activation

    Directory of Open Access Journals (Sweden)

    L. Andrew Bell

    2015-04-01

    Full Text Available Acetylcholine (ACh release onto nicotinic receptors directly activates subsets of inhibitory interneurons in hippocampal CA1. However, the specific interneurons activated and their effect on the hippocampal network is not completely understood. Therefore, we investigated subsets of hippocampal CA1 interneurons that respond to ACh release through the activation of nicotinic receptors and the potential downstream effects this may have on hippocampal CA1 network function. ACh was optogenetically released in mouse hippocampal slices by expressing the excitatory optogenetic protein oChIEF-tdTomato in medial septum/diagonal band of Broca cholinergic neurons using Cre recombinase-dependent adeno-associated viral mediated transfection. The actions of optogenetically released ACh were assessed on both pyramidal neurons and different interneuron subtypes via whole cell patch clamp methods. Vasoactive intestinal peptide (VIP-expressing interneurons that selectively innervate other interneurons (VIP/IS were excited by ACh through the activation of nicotinic receptors containing alpah4 and beta2 subunits (alpha4 beta2*. ACh release onto VIP/IS was presynaptically inhibited by M2 muscarinic autoreceptors. ACh release produced spontaneous inhibitory postsynaptic current (sIPSC barrages blocked by dihydro-beta-erythroidine in interneurons but not pyramidal neurons. Optogenetic suppression of VIP interneurons did not inhibit these sIPSC barrages suggesting other interneuron-selective interneurons were also excited by 42* nicotinic receptor activation. In contrast, interneurons that innervate pyramidal neuron perisomatic regions were not activated by ACh release onto nicotinic receptors. Therefore, we propose ACh release in CA1 facilitates disinhibition through activation of 42* nicotinic receptors on interneuron-selective interneurons whereas interneurons that innervate pyramidal neurons are less affected by nicotinic receptor activation.

  10. The urokinase plasminogen activator receptor-associated protein/endo180 is coexpressed with its interaction partners urokinase plasminogen activator receptor and matrix metalloprotease-13 during osteogenesis

    DEFF Research Database (Denmark)

    Engelholm, L H; Nielsen, B S; Netzel-Arnett, S;

    2001-01-01

    The urokinase plasminogen activator receptor-associated protein/Endo180 (uPARAP/Endo180) is a newly discovered member of the macrophage mannose receptor family that was reported to interact with ligand-bound urokinase plasminogen activator receptor (uPAR), matrix metalloprotease-13 (MMP-13), and ......, uPARAP/Endo180 expression was detected only in a mesenchymal condensation of the midbrain and in the developing lungs. The data suggest a function of this novel protease receptor in bone development, possibly mediated through its interactions with uPAR, MMP-13, or collagen V....

  11. Activation of the aryl hydrocarbon receptor reduces the number of precursor and effector T cells, but preserves thymic CD4(+)CD25(+)Foxp3(+) regulatory T cells

    NARCIS (Netherlands)

    Schulz, V.J.; Smit, J.J.; Bol-Schoenmakers, M.; van Duursen, M.B.M.; van den Berg, M.; Pieters, R.H.H.

    2012-01-01

    Aryl hydrocarbon receptor (AhR) activation suppresses immune responses, including allergic sensitization, by increasing the percentage of regulatory (Treg) cells. Furthermore, AhR activation is known to affect thymic precursor T cells. However, the effect of AhR activation on intrathymic CD4(+)CD25(

  12. Antitussive activity of Withania somnifera and opioid receptors.

    Science.gov (United States)

    Nosálová, Gabriela; Sivová, Veronika; Ray, Bimalendu; Fraňová, Soňa; Ondrejka, Igor; Flešková, Dana

    2015-01-01

    Arabinogalactan is a polysaccharide isolated from the roots of the medicinal plant Withania somnifera L. It contains 65% arabinose and 18% galactose. The aim of the present study was to evaluate the antitussive activity of arabinogalactan in conscious, healthy adult guinea pigs and the role of the opioid pathway in the antitussive action. A polysaccharide extract was given orally in a dose of 50 mg/kg. Cough was induced by an aerosol of citric acid in a concentration 0.3 mol/L, generated by a jet nebulizer into a plethysmographic chamber. The intensity of cough response was defined as the number of cough efforts counted during a 3-min exposure to the aerosol. The major finding was that arabinogalactan clearly suppressed the cough reflex; the suppression was comparable with that of codeine that was taken as a reference drug. The involvement of the opioid system was tested with the use of a blood-brain barrier penetrable, naloxone hydrochloride, and non-penetrable, naloxone methiodide, to distinguish between the central and peripheral mu-opioid receptor pathways. Both opioid antagonists acted to reverse the arabinogalactan-induced cough suppression; the reversion was total over time with the latter antagonist. We failed to confirm the presence of a bronchodilating effect of the polysaccharide, which could be involved in its antitussive action. We conclude that the polysaccharide arabinogalactan from Withania somnifera has a distinct antitussive activity consisting of cough suppression and that this action involves the mu-opioid receptor pathways.

  13. Vasopeptidase-activated latent ligands of the histamine receptor-1.

    Science.gov (United States)

    Gera, Lajos; Roy, Caroline; Charest-Morin, Xavier; Marceau, François

    2013-11-01

    Whether peptidases present in vascular cells can activate prodrugs active on vascular cells has been tested with 2 potential latent ligands of the histamine H1 receptor (H1R). First, a peptide consisting of the antihistamine cetirizine (CTZ) condensed at the N-terminus of ε-aminocaproyl-bradykinin (εACA-BK) was evaluated for an antihistamine activity that could be revealed by degradation of the peptide part of the molecule. CTZ-εACA-BK had a submicromolar affinity for the BK B2 receptor (B2R; IC50 of 590 nM, [(3)H]BK binding competition), but a non-negligible affinity for the human H1 receptor (H1R; IC50 of 11 μM for [(3)H]pyrilamine binding). In the human isolated umbilical vein, a system where both endogenous B2R and H1R mediate strong contractions, CTZ-εACA-BK exerted mild antagonist effects on histamine-induced contraction that were not modified by omapatrilat or by a B2R antagonist that prevents endocytosis of the BK conjugate. Cells expressing recombinant ACE or B2R incubated with CTZ-εACA-BK did not release a competitor of [(3)H]pyrilamine binding to H1Rs. Thus, there is no evidence that CTZ-εACA-BK can release free cetirizine in biological environments. The second prodrug was a blocked agonist, L-alanyl-histamine, potentially activated by aminopeptidase N (APN). This compound did not compete for [(3)H]pyrilamine binding to H1Rs. The human umbilical vein contractility assay responded to L-alanyl-histamine (EC50 54.7 μM), but the APN inhibitor amastatin massively (17-fold) reduced its apparent potency. Amastatin did not influence the potency of histamine as a contractile agent. One of the 2 tested latent H1R ligands, L-alanyl-histamine, supported the feasibility of pro-drug activation by vascular ectopeptidases.

  14. Relationship between somatostatin receptors and activation of hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    潘勤; 李定国; 陆汉明; 陆良勇; 尤汉宁; 徐芹芳

    2004-01-01

    Background Somafostatin receptors (SSTRs) have been suggested to involve in mediating the effect of somatostatin on hepatic stellate cells (HSCs) in an activation-dependent way. We, therefore, try to investigate the relationship between expression of SSTRs and activation of rat HSCs.Methods HSCs were isolated from rats by in situ perfusion and single-step density gradient centrifugation.SSTR1-5 mRNA levels in the differentiated first passage HSCs were detected by means of a reverse transcription polymerase chain reaction. On the other hand, hepatic fibrosis was induced in adult male Sprague-Dawley rats by carbon tetrachloride intoxication, and the expression of SSTR1-5 in normal as well as fibrotic livers was measured by immunohistochemical staining.Results SSTR mRNA and SSTR could not be found in freshly isolated rat HSCs or normal rat liver. However, SSTR1-3 mRNA appeared as HSCs became wholly activated, and could also be identified on the membrane of activated HSCs in the perisinusoid space, fibrous septa, etc.Conclusion The expression of SSTR1-3 in the rat HSC is closely related to its activation. This may reflect one of the main negative regulation mechanisms in the course of HSC activation.

  15. Litter environment affects behavior and brain metabolic activity of adult knockout mice

    Directory of Open Access Journals (Sweden)

    David Crews

    2009-08-01

    Full Text Available In mammals, the formative environment for social and anxiety-related behaviors is the family unit; in the case of rodents, this is the litter and the mother-young bond. A deciding factor in this environment is the sex ratio of the litter and, in the case of mice lacking functional copies of gene(s, the ratio of the various genotypes in the litter. Both Sex and Genotype ratios of the litter affect the nature and quality of the individual’s behavior later in adulthood, as well as metabolic activity in brain nuclei that underlie these behaviors. Mice were raised in litters reconstituted shortly after to birth to control for Sex ratio and Genotype ratio (wild type pups vs. pups lacking a functional estrogen receptor α. In both males and females the Sex and Genotype of siblings in the litter affected aggressive behaviors as well as patterns of metabolic activity in limbic nuclei in the social behavior network later in adulthood. Further, this pattern in males varied depending upon the Genotype of their brothers and sisters. Principal Components Analysis revealed two components comprised of several amygdalar and hypothalamic nuclei; the VMH showed strong correlations in both clusters, suggesting its pivotal nature in the organization of two neural networks.

  16. Activity-dependent neurotransmitter-receptor matching at the neuromuscular junction.

    Science.gov (United States)

    Borodinsky, Laura N; Spitzer, Nicholas C

    2007-01-02

    Signaling in the nervous system requires matching of neurotransmitter receptors with cognate neurotransmitters at synapses. The vertebrate neuromuscular junction is the best studied cholinergic synapse, but the mechanisms by which acetylcholine is matched with acetylcholine receptors are not fully understood. Because alterations in neuronal calcium spike activity alter transmitter specification in embryonic spinal neurons, we hypothesized that receptor expression in postsynaptic cells follows changes in transmitter expression to achieve this specific match. We find that embryonic vertebrate striated muscle cells normally express receptors for glutamate, GABA, and glycine as well as for acetylcholine. As maturation progresses, acetylcholine receptor expression prevails. Receptor selection is altered when early neuronal calcium-dependent activity is perturbed, and remaining receptor populations parallel changes in transmitter phenotype. In these cases, glutamatergic, GABAergic, and glycinergic synaptic currents are recorded from muscle cells, demonstrating that activity regulates matching of transmitters and their receptors in the assembly of functional synapses.

  17. Involvement of Activating NK Cell Receptors and Their Modulation in Pathogen Immunity

    Directory of Open Access Journals (Sweden)

    Francesco Marras

    2011-01-01

    Full Text Available Natural Killer (NK cells are endowed with cell-structure-sensing receptors providing inhibitory protection from self-destruction (inhibitory NK receptors, iNKRs, including killer inhibitory receptors and other molecules and rapid triggering potential leading to functional cell activation by Toll-like receptors (TLRs, cytokine receptors, and activating NK cell receptors including natural cytotoxicity receptors (NCRs, i.e., NKp46, NKp46, and NKp44. NCR and NKG2D recognize ligands on infected cells which may be endogenous or may directly bind to some structures derived from invading pathogens. In this paper, we address the known direct or indirect interactions between activating receptors and pathogens and their expression during chronic HIV and HCV infections.

  18. The relationship between activating affects, inhibitory affects, and self-compassion in patients with Cluster C personality disorders.

    Science.gov (United States)

    Schanche, Elisabeth; Stiles, Tore C; McCullough, Leigh; Svartberg, Martin; Nielsen, Geir Høstmark

    2011-09-01

    In the short-term dynamic psychotherapy model termed "Affect Phobia Treatment," it is assumed that increase in patients' defense recognition, decrease in inhibitory affects (e.g., anxiety, shame, guilt), and increase in the experience of activating affects (e.g., sadness, anger, closeness) are related to enhanced self-compassion across therapeutic approaches. The present study aimed to test this assumption on the basis of data from a randomized controlled trial, which compared a 40-session short-term dynamic psychotherapy (N = 25) with 40-session cognitive treatment (N = 25) for outpatients with Cluster C personality disorders. Patients' defense recognition, inhibitory affects, activating affects, and self-compassion were rated with the Achievement of Therapeutic Objectives Scale (McCullough et al., 2003b) in Sessions 6 and 36. Results showed that increase in self-compassion from early to late in therapy significantly predicted pre- to post-decrease in psychiatric symptoms, interpersonal problems, and personality pathology. Decrease in levels of inhibitory affects and increase in levels of activating affects during therapy were significantly associated with higher self-compassion toward the end of treatment. Increased levels of defense recognition did not predict higher self-compassion when changes in inhibitory and activating affects were statistically controlled for. There were no significant interaction effects with type of treatment. These findings support self-compassion as an important goal of psychotherapy and indicate that increase in the experience of activating affects and decrease in inhibitory affects seem to be worthwhile therapeutic targets when working to enhance self-compassion in patients with Cluster C personality disorders.

  19. Selective 5-HT7 Receptor Activation May Enhance Synaptic Plasticity Through N-methyl-D-aspartate (NMDA) Receptor Activity in the Visual Cortex.

    Science.gov (United States)

    Xiang, Kangjian; Zhao, Xuefei; Li, Youjun; Zheng, Liang; Wang, Jue; Li, Yan-Hai

    2016-01-01

    Serotonin (5-hydroxytryptamine, 5-HT) is an important neurotransmitter that modulates N-methyl-D-aspartate (NMDA) receptor activity by binding to several different 5-HT receptor subtypes. In the present study, we used whole-cell patch-clamp recordings in transverse slice preparations to test the role of 5-HT receptors in modulating the NMDA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in layer II/III pyramidal neurons of the rat visual cortex. We found that the NMDA receptor-mediated component of mEPSCs could be potentiated by exogenously applied 5-HT. Similar results were obtained by exogenously applied 5-CT or 8-OH-DPAT (the 5-HT1A and 5-HT7 receptor agonist). A specific antagonist for the 5-HT7 receptor, SB-269970, completely blocked the increase in NMDA receptor-mediated component of mEPSCs by 5-CT or 8- OH-DPAT. Moreover, the selective 5-HT1A receptor antagonist, WAY-100135, displayed no influence on the enhancement in NMDA receptor-mediated component of mEPSCs by 5-CT or 8-OHDPAT. These results indicated that the increase in NMDA receptor-mediated component of mEPSCs by 5-HT in layer II/III pyramidal neurons of the young rat visual cortex requires activation of 5-HT7 receptors, but not 5-HT1A receptors. These observations might be clinically relevant to schizophrenia and Alzheimer's disease (AD), where enhancing NMDA receptor-mediated neurotransmission is considered to be a promising strategy for treatment of these diseases.

  20. NMDA receptor activity and the transmission of sensory input into motor output in introverts and extraverts.

    Science.gov (United States)

    Rammsayer, Thomas H

    2003-05-01

    Recent research suggests that individual differences in brain dopamine functioning may be related to the personality dimension of extraversion. The major goal of the present study was to answer the question of whether a pharmacologically induced change in glutamatergic NMDA receptor activity would also differentially affect the transmission of sensory input into motor out-put in introverts and extraverts. Therefore, in a double-blind within-subjects design, either 30 mg of the NMDA receptor antagonist memantine or placebo were administered to 48 healthy male volunteers before performing a choice reaction-time task. In introverts, memantine caused a pronounced increase in lift-off time (i.e., the time required to lift the finger from a home button) compared to that in extraverts, whereas movement time (i.e., the time required to move the finger from the home button to a response button) was decreased in both groups. The pattern of results suggests that extraversion-related differential sensitivity to pharmacologically induced changes in NMDA receptor activity is limited to functions that involve an interaction between the glutamatergic and dopaminergic systems.

  1. 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.

  2. Angiotensin II activates endothelial constitutive nitric oxide synthase via AT1 receptors.

    Science.gov (United States)

    Saito, S; Hirata, Y; Emori, T; Imai, T; Marumo, F

    1996-09-01

    To determine whether angiotensin (ANG) II, a vasoconstrictor hormone, activates constitutive nitric oxide synthase (cNOS) in endothelial cells (ECs), we investigated the cellular mechanism by which ANG II induces nitric oxide (NO) formation in cultured bovine ECs. ANG II rapidly (within 1 min) and dose-dependently (10(-9)-10(-6) M) increased nitrate/nitrite (NOx) production. This effect of ANG II was abolished by a NOS inhibitor, NG-monomethyl-L-arginine. An ANG II type 1 (AT1) receptor antagonist (DuP 753), but not an ANG II type 2 (AT2) receptor antagonist (PD 123177), dose-dependently inhibited ANG II-induced NOx production. A Ca(2+)-channel blocker (barnidipine) failed to affect ANG II-induced NOx production, whereas an intracellular Ca2+ chelator (BAPTA) and a calmodulin inhibitor (W-7) abolished NOx production induced by ANG II. A protein kinase C (PKC) inhibitor (H-7) and down-regulation of endogenous PKC after pretreatment with phorbol ester decreased NOx production stimulated by ANG II. ANG II transiently stimulated inositol 1,4,5-trisphosphate (IP3) formation, and increased cytosolic free Ca2+ concentrations; these effects were blocked by DuP 753. Our data demonstrate that ANG II stimulates NO release by activation of Ca2+/calmodulin-dependent cNOS via AT1 receptors in bovine ECs.

  3. Activation of cardiac ryanodine receptors by cardiac glycosides.

    Science.gov (United States)

    Sagawa, Toshio; Sagawa, Kazuko; Kelly, James E; Tsushima, Robert G; Wasserstrom, J Andrew

    2002-03-01

    This study investigated the effects of cardiac glycosides on single-channel activity of the cardiac sarcoplasmic reticulum (SR) Ca2+ release channels or ryanodine receptor (RyR2) channels and how this action might contribute to their inotropic and/or toxic actions. Heavy SR vesicles isolated from canine left ventricle were fused with artificial planar lipid bilayers to measure single RyR2 channel activity. Digoxin and actodigin increased single-channel activity at low concentrations normally associated with therapeutic plasma levels, yielding a 50% of maximal effect of approximately 0.2 nM for each agent. Channel activation by glycosides did not require MgATP and occurred only when digoxin was applied to the cytoplasmic side of the channel. Similar results were obtained in human RyR2 channels; however, neither the crude skeletal nor the purified cardiac channel was activated by glycosides. Channel activation was dependent on [Ca2+] on the luminal side of the bilayer with maximal stimulation occurring between 0.3 and 10 mM. Rat RyR2 channels were activated by digoxin only at 1 microM, consistent with the lower sensitivity to glycosides in rat heart. These results suggest a model in which RyR2 channel activation by digoxin occurs only when luminal [Ca2+] was increased above 300 microM (in the physiological range). Consequently, increasing SR load (by Na+ pump inhibition) serves to amplify SR release by promoting direct RyR2 channel activation via a luminal Ca2+-sensitive mechanism. This high-affinity effect of glycosides could contribute to increased SR Ca2+ release and might play a role in the inotropic and/or toxic actions of glycosides in vivo.

  4. RELATIONSHIP BETWEEN SOMATOSTATIN RECEPTORS AND ACTIVATION OF HEPATIC STELLATE CELL

    Institute of Scientific and Technical Information of China (English)

    潘勤; 李定国; 陆汉明; 尤汉宁; 徐芹芳; 陆良勇

    2004-01-01

    Objective To investigate the relationship between expression of somatostatin receptors (SSTRs) and activation of rat hepatic stellate cell (HSC). Methods HSCs were isolated from rats by in situ perfusion and single-step density gradient centrifugation, and then SSTR1 ~5 mRNA levels in the differentiated first passage HSCs were detected by means of reverse transcription polymerase chain reaction. On the other hand, hepatic fibrosis was induced in adult male Sprague-Dawley rats by carbon tetrachloride intoxication, and the expression of SSTR1 ~5 in normal as well as fibrotic liver was measured by immunohistochemical staining. Results SSTR mRNA and SSTR could not be found in freshly isolated rat HSCs and normal rat liver. But SSTR1~3 mRNA appeared as HSCs became wholly activated, and SSTR1 ~3 could also be identified on the membrane of activated HSCs in the perisinusoid space, fibrous septa, etc Conclusion The expression of SSTR1~3 in the rat HSC is closely related to its activation. This may reflect one of the main negative regulation mechanisms in the course of HSC activation.

  5. Increased peroxisome proliferator-activated receptor-gamma activity reduces imatinib uptake and efficacy in chronic myeloid leukemia mononuclear cells.

    Science.gov (United States)

    Wang, Jueqiong; Lu, Liu; Kok, Chung H; Saunders, Verity A; Goyne, Jarrad M; Dang, Phuong; Leclercq, Tamara M; Hughes, Timothy P; White, Deborah L

    2017-02-02

    Imatinib is actively transported by OCT-1 influx transporter, and low OCT-1 activity in diagnostic chronic myeloid leukemia blood mononuclear cells is significantly associated with poor molecular response to imatinib. Here we report that, in diagnostic chronic myeloid leukemia mononuclear cells and BCR-ABL1+ cell lines, peroxisome proliferator-activated receptor gamma agonists (GW1929, rosiglitazone, pioglitazone) significantly decrease OCT-1 activity; conversely, peroxisome proliferator-activated receptor gamma antagonists (GW9662, T0070907) increase OCT-1 activity. Importantly, these effects can lead to corresponding changes in sensitivity to Bcr-Abl kinase inhibition. Results were confirmed in peroxisome proliferator-activated receptor gamma-transduced K562 cells. Furthermore, we identified a strong negative correlation between OCT-1 activity and peroxisome proliferator-activated receptor gamma transcriptional activity in diagnostic chronic myeloid leukemia patients (n=84; preceptor gamma activation has a negative impact on the intracellular uptake of imatinib and consequent Bcr-Abl kinase inhibition. The inter-patient variability of peroxisome proliferator-activated receptor gamma activation likely accounts for the heterogeneity observed in patient OCT-1 activity at diagnosis. Recently, the peroxisome proliferator-activated receptor gamma agonist pioglitazone was reported to act synergistically with imatinib targeting the residual chronic myeloid leukemia stem cell pool. Our findings suggest that peroxisome proliferator-activated receptor gamma ligands have differential effects on circulating mononuclear cells compared to stem cells. Since the effect of peroxisome proliferator-activated receptor gamma activation on imatinib uptake in mononuclear cells may counteract the clinical benefit of this activation in stem cells, caution should be applied when combining these therapies, especially in patients with high peroxisome proliferator-activated receptor gamma

  6. Adipocyte Mineralocorticoid Receptor Activation Leads to Metabolic Syndrome and Induction of Prostaglandin D2 Synthase.

    Science.gov (United States)

    Urbanet, Riccardo; Nguyen Dinh Cat, Aurelie; Feraco, Alessandra; Venteclef, Nicolas; El Mogrhabi, Soumaya; Sierra-Ramos, Catalina; Alvarez de la Rosa, Diego; Adler, Gail K; Quilliot, Didier; Rossignol, Patrick; Fallo, Francesco; Touyz, Rhian M; Jaisser, Frédéric

    2015-07-01

    Metabolic syndrome is a major risk factor for the development of diabetes mellitus and cardiovascular diseases. Pharmacological antagonism of the mineralocorticoid receptor (MR), a ligand-activated transcription factor, limits metabolic syndrome in preclinical models, but mechanistic studies are lacking to delineate the role of MR activation in adipose tissue. In this study, we report that MR expression is increased in visceral adipose tissue in a preclinical mouse model of metabolic syndrome and in obese patients. In vivo conditional upregulation of MR in mouse adipocytes led to increased weight and fat mass, insulin resistance, and metabolic syndrome features without affecting blood pressure. We identified prostaglandin D2 synthase as a novel MR target gene in adipocytes and AT56, a specific inhibitor of prostaglandin D2 synthase enzymatic activity, blunted adipogenic aldosterone effects. Moreover, translational studies showed that expression of MR and prostaglandin D2 synthase is strongly correlated in adipose tissues from obese patients.

  7. Activation of both Group I and Group II metabotropic glutamatergic receptors suppress retinogeniculate transmission.

    Science.gov (United States)

    Lam, Y-W; Sherman, S M

    2013-07-09

    Relay cells of dorsal lateral geniculate nucleus (LGN) receive a Class 1 glutamatergic input from the retina and a Class 2 input from cortical layer 6. Among the properties of Class 2 synapses is the ability to activate metabotropic glutamate receptors (mGluRs), and mGluR activation is known to affect thalamocortical transmission via regulating retinogeniculate and thalamocortical synapses. Using brain slices, we studied the effects of Group I (dihydroxyphenylglycine) and Group II ((2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine) mGluR agonists on retinogeniculate synapses. We showed that both agonists inhibit retinogeniculate excitatory postsynaptic currents (EPSCs) through presynaptic mechanisms, and their effects are additive and independent. We also found high-frequency stimulation of the layer 6 corticothalamic input produced a similar suppression of retinogeniculate EPSCs, suggesting layer 6 projection to LGN as a plausible source of activating these presynaptic mGluRs.

  8. New insights into the structural bases of activation of Cys-loop receptors.

    Science.gov (United States)

    Bouzat, Cecilia

    2012-01-01

    Neurotransmitter receptors of the Cys-loop superfamily mediate rapid synaptic transmission throughout the nervous system, and include receptors activated by ACh, GABA, glycine and serotonin. They are involved in physiological processes, including learning and memory, and in neurological disorders, and they are targets for clinically relevant drugs. Cys-loop receptors assemble either from five copies of one type of subunit, giving rise to homomeric receptors, or from several types of subunits, giving rise to heteromeric receptors. Homomeric receptors are invaluable models for probing fundamental relationships between structure and function. Receptors contain a large extracellular domain that carries the binding sites and a transmembrane region that forms the ion pore. How the structural changes elicited by agonist binding are propagated through a distance of 50Å to the ion channel gate is central to understanding receptor function. Depending on the receptor subtype, occupancy of either two, as in the prototype muscle nicotinic receptor, or three binding sites, as in homomeric receptors, is required for full activation. The conformational changes initiated at the binding sites are propagated to the gate through the interface between the extracellular and transmembrane domains. This region forms a network that relays structural changes from the binding site towards the pore, and also contributes to open channel lifetime and rate of desensitization. Thus, this coupling region controls the beginning and duration of a synaptic response. Here we review recent advances in the molecular mechanism by which Cys-loop receptors are activated with particular emphasis on homomeric receptors.

  9. The role of GH receptor tyrosine phosphorylation in Stat5 activation

    DEFF Research Database (Denmark)

    Hansen, J A; Hansen, L H; Wang, X;

    1997-01-01

    Stimulation of GH receptors leads to rapid activation of Jak2 kinase and subsequent tyrosine phosphorylation of the GH receptor. Three specific tyrosines located in the C-terminal domain of the GH receptor have been identified as being involved in GH-stimulated transcription of the Spi 2.1 promoter....... Mutated GH receptors lacking all but one of these three tyrosines are able to mediate a transcriptional response when transiently transfected into CHO cells together with a Spi 2.1 promoter/luciferase construct. Similarly, these GH receptors were found to be able to mediate activation of Stat5 DNA......-binding activity, whereas the GH receptor mutant lacking all intracellular tyrosines was not. Synthetic tyrosine phosphorylated peptides corresponding to the GH receptor sequence around the three tyrosines inhibited Stat5 DNA-binding activity while their non-phosphorylated counterparts were ineffective. Tyrosine...

  10. The adipogenic acetyltransferase Tip60 targets activation function 1 of peroxisome proliferator-activated receptor gamma

    DEFF Research Database (Denmark)

    van Beekum, Olivier; Brenkman, Arjan B; Grøntved, Lars;

    2008-01-01

    The transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) plays a key role in the regulation of lipid and glucose metabolism in adipocytes, by regulating their differentiation, maintenance, and function. The transcriptional activity of PPARgamma is dictated by the set...... of proteins with which this nuclear receptor interacts under specific conditions. Here we identify the HIV-1 Tat-interacting protein 60 (Tip60) as a novel positive regulator of PPARgamma transcriptional activity. Using tandem mass spectrometry, we found that PPARgamma and the acetyltransferase Tip60 interact...... in cells, and through use of chimeric proteins, we established that coactivation by Tip60 critically depends on the N-terminal activation function 1 of PPARgamma, a domain involved in isotype-specific gene expression and adipogenesis. Chromatin immunoprecipitation experiments showed that the endogenous Tip...

  11. Role of ELA region in auto-activation of mutant KIT receptor: a molecular dynamics simulation insight.

    Science.gov (United States)

    Purohit, Rituraj

    2014-01-01

    KIT receptor is the prime target in gastrointestinal stromal tumor (GISTs) therapy. Second generation inhibitor, Sunitinib, binds to an inactivated conformation of KIT receptor and stabilizes it in order to prevent tumor formation. Here, we investigated the dynamic behavior of wild type and mutant D816H KIT receptor, and emphasized the extended A-loop (EAL) region (805-850) by conducting molecular dynamics simulation (∼100 ns). We analyzed different properties such as root mean square cutoff or deviation, root mean square fluctuation, radius of gyration, solvent-accessible surface area, hydrogen bonding network analysis, and essential dynamics. Apart from this, clustering and cross-correlation matrix approach was used to explore the conformational space of the wild type and mutant EAL region of KIT receptor. Molecular dynamics analysis indicated that mutation (D816H) was able to alter intramolecular hydrogen bonding pattern and affected the structural flexibility of EAL region. Moreover, flexible secondary elements, specially, coil and turns were dominated in EAL region of mutant KIT receptor during simulation. This phenomenon increased the movement of EAL region which in turn helped in shifting the equilibrium towards the active kinase conformation. Our atomic investigation of mutant KIT receptor which emphasized on EAL region provided a better insight into the understanding of Sunitinib resistance mechanism of KIT receptor and would help to discover new therapeutics for KIT-based resistant tumor cells in GIST therapy.

  12. SHP-1 phosphatase activity counteracts increased T cell receptor affinity.

    Science.gov (United States)

    Hebeisen, Michael; Baitsch, Lukas; Presotto, Danilo; Baumgaertner, Petra; Romero, Pedro; Michielin, Olivier; Speiser, Daniel E; Rufer, Nathalie

    2013-03-01

    Anti-self/tumor T cell function can be improved by increasing TCR-peptide MHC (pMHC) affinity within physiological limits, but paradoxically further increases (K(d) affinity for the tumor antigen HLA-A2/NY-ESO-1, we investigated the molecular mechanisms underlying this high-affinity-associated loss of function. As compared with cells expressing TCR affinities generating optimal function (K(d) = 5 to 1 μM), those with supraphysiological affinity (K(d) = 1 μM to 15 nM) showed impaired gene expression, signaling, and surface expression of activatory/costimulatory receptors. Preferential expression of the inhibitory receptor programmed cell death-1 (PD-1) was limited to T cells with the highest TCR affinity, correlating with full functional recovery upon PD-1 ligand 1 (PD-L1) blockade. In contrast, upregulation of the Src homology 2 domain-containing phosphatase 1 (SHP-1/PTPN6) was broad, with gradually enhanced expression in CD8(+) T cells with increasing TCR affinities. Consequently, pharmacological inhibition of SHP-1 with sodium stibogluconate augmented the function of all engineered T cells, and this correlated with the TCR affinity-dependent levels of SHP-1. These data highlight an unexpected and global role of SHP-1 in regulating CD8(+) T cell activation and responsiveness and support the development of therapies inhibiting protein tyrosine phosphatases to enhance T cell-mediated immunity.

  13. Molecular pharmacological phenotyping of EBI2. An orphan seven-transmembrane receptor with constitutive activity

    DEFF Research Database (Denmark)

    Rosenkilde, Mette M; Benned-Jensen, Tau; Holst, Peter J;

    2006-01-01

    Epstein-Barr virus (EBV)-induced receptor 2 (EBI2) is an orphan seven-transmembrane (7TM) receptor originally identified as the most up-regulated gene (>200-fold) in EBV-infected cells. Here we show that EBI2 signals with constitutive activity through Galpha(i) as determined by a receptor-mediate...

  14. Developmental stability of taurine's activation on glycine receptors in cultured neurons of rat auditory cortex.

    Science.gov (United States)

    Tang, Zheng-Quan; Lu, Yun-Gang; Chen, Lin

    2008-01-03

    Taurine is an endogenous amino acid that can activate glycine and/or gamma-aminobutyric acid type A (GABA(A)) receptors in the central nervous system. During natural development, taurine's receptor target undergoes a shift from glycine receptors to GABA(A) receptors in cortical neurons. Here, we demonstrate that taurine's receptor target in cortical neurons remains stable during in vitro development. With whole-cell patch-clamp recordings, we found that taurine always activated glycine receptors, rather than GABA(A) receptors, in neurons of rat auditory cortex cultured for 5-22 days. Our results suggest that the functional sensitivity of glycine and GABA(A) receptors to taurine is critically regulated by their developmental environments.

  15. Farnesoid X Receptor Inhibits the Transcriptional Activity of Carbohydrate Response Element Binding Protein in Human Hepatocytes

    Science.gov (United States)

    Caron, Sandrine; Huaman Samanez, Carolina; Dehondt, Hélène; Ploton, Maheul; Briand, Olivier; Lien, Fleur; Dorchies, Emilie; Dumont, Julie; Postic, Catherine; Cariou, Bertrand; Lefebvre, Philippe

    2013-01-01

    The glucose-activated transcription factor carbohydrate response element binding protein (ChREBP) induces the expression of hepatic glycolytic and lipogenic genes. The farnesoid X receptor (FXR) is a nuclear bile acid receptor controlling bile acid, lipid, and glucose homeostasis. FXR negatively regulates hepatic glycolysis and lipogenesis in mouse liver. The aim of this study was to determine whether FXR regulates the transcriptional activity of ChREBP in human hepatocytes and to unravel the underlying molecular mechanisms. Agonist-activated FXR inhibits glucose-induced transcription of several glycolytic genes, including the liver-type pyruvate kinase gene (L-PK), in the immortalized human hepatocyte (IHH) and HepaRG cell lines. This inhibition requires the L4L3 region of the L-PK promoter, known to bind the transcription factors ChREBP and hepatocyte nuclear factor 4α (HNF4α). FXR interacts directly with ChREBP and HNF4α proteins. Analysis of the protein complex bound to the L4L3 region reveals the presence of ChREBP, HNF4α, FXR, and the transcriptional coactivators p300 and CBP at high glucose concentrations. FXR activation does not affect either FXR or HNF4α binding to the L4L3 region but does result in the concomitant release of ChREBP, p300, and CBP and in the recruitment of the transcriptional corepressor SMRT. Thus, FXR transrepresses the expression of genes involved in glycolysis in human hepatocytes. PMID:23530060

  16. Inhibition of Activity of GABA Transporter GAT1 by δ-Opioid Receptor

    Directory of Open Access Journals (Sweden)

    Lu Pu

    2012-01-01

    Full Text Available Analgesia is a well-documented effect of acupuncture. A critical role in pain sensation plays the nervous system, including the GABAergic system and opioid receptor (OR activation. Here we investigated regulation of GABA transporter GAT1 by δOR in rats and in Xenopus oocytes. Synaptosomes of brain from rats chronically exposed to opiates exhibited reduced GABA uptake, indicating that GABA transport might be regulated by opioid receptors. For further investigation we have expressed GAT1 of mouse brain together with mouse δOR and μOR in Xenopus oocytes. The function of GAT1 was analyzed in terms of Na+-dependent [3H]GABA uptake as well as GAT1-mediated currents. Coexpression of δOR led to reduced number of fully functional GAT1 transporters, reduced substrate translocation, and GAT1-mediated current. Activation of δOR further reduced the rate of GABA uptake as well as GAT1-mediated current. Coexpression of μOR, as well as μOR activation, affected neither the number of transporters, nor rate of GABA uptake, nor GAT1-mediated current. Inhibition of GAT1-mediated current by activation of δOR was confirmed in whole-cell patch-clamp experiments on rat brain slices of periaqueductal gray. We conclude that inhibition of GAT1 function will strengthen the inhibitory action of the GABAergic system and hence may contribute to acupuncture-induced analgesia.

  17. 4-Methylthiobutyl isothiocyanate (Erucin) from rocket plant dichotomously affects the activity of human immunocompetent cells.

    Science.gov (United States)

    Gründemann, Carsten; Garcia-Käufer, Manuel; Lamy, Evelyn; Hanschen, Franziska S; Huber, Roman

    2015-03-15

    Isothiocyanates (ITC) from the Brassicaceae plant family are regarded as promising for prevention and treatment of cancer. However, experimental settings consider their therapeutic action without taking into account the risk of unwanted effects on healthy tissues. In the present study we investigated the effects of Eruca sativa seed extract containing MTBITC (Erucin) and pure Erucin from rocket plant on healthy cells of the human immune system in vitro. Hereby, high doses of the plant extract as well as of Erucin inhibited cell viability of human lymphocytes via induction of apoptosis to comparable amounts. Non-toxic low concentrations of the plant extract and pure Erucin altered the expression of the interleukin (IL)-2 receptor but did not affect further T cell activation, proliferation and the release of the effector molecules interferon (IFN)-gamma and IL-2 of T-lymphocytes. However, the activity of NK-cells was significantly reduced by non-toxic concentrations of the plant extract and pure Erucin. These results indicate that the plant extract and pure Erucin interfere with the function of human T lymphocytes and decreases the activity of NK-cells in comparable concentrations. Long-term clinical studies with ITC-enriched plant extracts from Brassicaceae should take this into account.

  18. Stabilizing effects of G protein on the active conformation of adenosine A1 receptor differ depending on G protein type.

    Science.gov (United States)

    Tateyama, Michihiro; Kubo, Yoshihiro

    2016-10-05

    G protein coupled receptors (GPCRs) trigger various cellular and physiological responses upon the ligand binding. The ligand binding induces conformational change in GPCRs which allows G protein to interact with the receptor. The interaction of G protein also affects the active conformation of GPCRs. In this study, we have investigated the effects of Gαi1, Gαo and chimeric Gαqi5 on the active conformation of the adenosine A1 receptor, as each Gα showed difference in the interaction with adenosine A1 receptor. The conformational changes in the adenosine A1 receptor were detected as the agonist-induced decreases in efficiency of Förster resonance energy transfer (FRET) between fluorescent proteins (FPs) fused at the two intracellular domains of the adenosine A1 receptor. Amplitudes of the agonist-induced FRET decreases were subtle when the FP-tagged adenosine A1 receptor was expressed alone, whereas they were significantly enhanced when co-expressed with Gαi1Gβ1Gγ22 (Gi1) or Gαqi5Gβ1Gγ22 (Gqi5) but not with GαοGβ1Gγ22 (Go). The enhancement of the agonist-induced FRET decrease in the presence of Gqi5 was significantly larger than that of Gi1. Furthermore, the FRET recovery upon the agonist removal in the presence of Gqi5 was significantly slower than that of Gi1. From these results it was revealed that the agonist-bound active conformation of adenosine A1 receptor is unstable without the binding of G protein and that the stabilizing effects of G protein differ depending on the types of G protein.

  19. High-affinity benzodiazepine receptor ligands among benzodiazepines and betacarbolines with different intrinsic activity

    Energy Technology Data Exchange (ETDEWEB)

    Yliniemelae, A.; Gynther, J. (Univ. of Kuopio (Finland)); Konschin, H.; Tylli, H. (Univ. of Helsinki (Finland)); Rouvinen, J. (Univ. of Joensuu (Finland))

    1989-01-01

    Structural and electrostatic features of diazepam, flumazenil, and methyl betacarboline-3-carboxylate (BCCM) have been investigated using the molecular superimposition method. These high-affinity benzodiazepine (BZ) receptor ligands are structurally unrelated and they have different intrinsic activity. These ligands are superimposed in such a way that common structural and electrostatic features essential for the high receptor binding affinity overlap. In addition to this binding pharmacophore, there are roughly three separate binding zones in the BZ receptor, one for each class of ligands. The intrinsic activity of BZ receptor ligands depends on the molecular structures and the way the ligand approaches the receptor.

  20. Prostate stem cell antigen interacts with nicotinic acetylcholine receptors and is affected in Alzheimer's disease

    DEFF Research Database (Denmark)

    Jensen, Majbrit Myrup; Mikkelsen, Jens D.; Arvaniti, Maria;

    2015-01-01

    Alzheimer's disease (AD) is a neurodegenerative disorder involving impaired cholinergic neurotransmission and dysregulation of nicotinic acetylcholine receptors (nAChRs). Ly-6/neurotoxin (Lynx) proteins have been shown to modulate cognition and neural plasticity by binding to nAChR subtypes...

  1. Two polymorphisms in the glucocorticoid receptor gene directly affect glucocorticoid-regulated gene expression.

    NARCIS (Netherlands)

    H. Russcher (Henk); P. Smit (Pauline); E.L.T. van den Akker (Erica); E.F.C. van Rossum (Liesbeth); A.O. Brinkmann (Albert); F.H. de Jong (Frank); S.W.J. Lamberts (Steven); J.W. Koper (Jan)

    2005-01-01

    textabstractCONTEXT: Interindividual variation in glucocorticoid (GC)-sensitivity can be partly explained by polymorphisms in the GC receptor (GR) gene. The ER22/23EK and N363S polymorphisms have been described to be associated with lower and higher GC sensitivity, respectively. OBJECTIVE AND DESIGN

  2. Factors affecting estrogen receptor status in a multiracial Asian country : An analysis of 3557 cases

    NARCIS (Netherlands)

    Yip, C. H.; Pathy, N. Bhoo; Uiterwaal, C. S.; Taib, N. A.; Tan, G. H.; Mun, K. S.; Choo, W. Y.; Rhodes, A.

    2011-01-01

    Estrogen receptor (ER) positive rates in breast cancer may be influenced by grade, stage, age and race. This study reviews the ER positive rates over a 15-year period at the University Malaya Medical Centre, Kuala Lumpur, Malaysia. Data on ER status of 3557 patients from 1994 to 2008 was analyzed. E

  3. Family C 7TM receptor dimerization and activation

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Sheikh, Søren P; Hansen, Jakob Lerche

    2006-01-01

    The family C seven transmembrane (7TM) receptors constitutes a small and especially well characterized subfamily of the large 7TM receptor superfamily. Approximately 50% of current prescription drugs target 7TM receptors, this biologically important family represents the largest class of drug-tar...

  4. Peptides derived from specific interaction sites of the fibroblast growth factor 2 - FGF receptor complexes induce receptor activation and signaling

    DEFF Research Database (Denmark)

    Manfè, Valentina; Kochoyan, Artur; Bock, Elisabeth

    2010-01-01

    J. Neurochem. (2010) 10.1111/j.1471-4159.2010.06718.x Abstract Basic fibroblast growth factor (FGF2, bFGF) is the most extensively studied member of the FGF family and is involved in neurogenesis, differentiation, neuroprotection, and synaptic plasticity in the CNS. FGF2 executes its pleiotropic...... biologic actions by binding, dimerizing, and activating FGF receptors (FGFRs). The present study reports the physiologic impact of various FGF2-FGFR1 contact sites employing three different synthetic peptides, termed canofins, designed based on structural analysis of the interactions between FGF2 and FGFR1....... Canofins mimic the cognate ligand interaction with the receptor and preserve the neuritogenic and neuroprotective properties of FGF2. Canofins were shown by surface plasmon resonance analysis to bind to FGFR1 and promote receptor activation. However, FGF2-induced receptor phosphorylation was inhibited...

  5. Mu-opioid receptor knockout mice show diminished food-anticipatory activity

    NARCIS (Netherlands)

    Kas, Martien J H; van den Bos, Ruud; Baars, Annemarie M; Lubbers, Marianne; Lesscher, Heidi M B; Hillebrand, Jacquelien J G; Schuller, Alwin G; Pintar, John E; Spruijt, Berry M

    2004-01-01

    We have previously suggested that during or prior to activation of anticipatory behaviour to a coming reward, mu-opioid receptors are activated. To test this hypothesis schedule induced food-anticipatory activity in mu-opioid receptor knockout mice was measured using running wheels. We hypothesized

  6. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-delta

    DEFF Research Database (Denmark)

    Yan, Zhen Cheng; Liu, Dao Yan; Zhang, Li Li

    2007-01-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-delta (PPAR-delta)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow...... or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each p...

  7. Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression.

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    Ariadna Amador

    Full Text Available The nuclear receptors REV-ERBα and REV-ERBβ are transcription factors that play pivotal roles in the regulation of the circadian rhythm and various metabolic processes. The circadian rhythm is an endogenous mechanism, which generates entrainable biological changes that follow a 24-hour period. It regulates a number of physiological processes, including sleep/wakeful cycles and feeding behaviors. We recently demonstrated that REV-ERB-specific small molecules affect sleep and anxiety. The orexinergic system also plays a significant role in mammalian physiology and behavior, including the regulation of sleep and food intake. Importantly, orexin genes are expressed in a circadian manner. Given these overlaps in function and circadian expression, we wanted to determine whether the REV-ERBs might regulate orexin. We found that acute in vivo modulation of REV-ERB activity, with the REV-ERB-specific synthetic ligand SR9009, affects the circadian expression of orexinergic genes in mice. Long term dosing with SR9009 also suppresses orexinergic gene expression in mice. Finally, REV-ERBβ-deficient mice present with increased orexinergic transcripts. These data suggest that the REV-ERBs may be involved in the repression of orexinergic gene expression.

  8. Immunomodulator CD200 promotes neurotrophic activity by interacting with and activating the fibroblast growth factor receptor

    DEFF Research Database (Denmark)

    Pankratova, Stanislava; Bjornsdottir, Halla; Christensen, Claus;

    2016-01-01

    in the suppression of microglia activation. We for the first time demonstrated that CD200 can interact with and transduce signaling through activation of the fibroblast growth factor receptor (FGFR), thereby inducing neuritogenesis and promoting neuronal survival in primary neurons. CD200-induced FGFR...... phosphorylation was abrogated by CD200R, whereas FGF2-induced FGFR activation was inhibited by CD200. We also identified a sequence motif located in the first Ig-like module of CD200, likely representing the minimal CD200 binding site for FGFR. The FGFR binding motif overlaps with the CD200R binding site......, suggesting that they can compete for CD200 binding in cells that express both receptors. We propose that CD200 in neurons functions as a ligand of FGFR....

  9. Significance of AT1 receptor independent activation of mineralocorticoid receptor in murine diabetic cardiomyopathy.

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    Yuji Nagatomo

    Full Text Available BACKGROUND: Diabetes mellitus (DM has deleterious influence on cardiac performance independent of coronary artery disease and hypertension. The objective of the present study was to investigate the role of the renin-angiotensin-aldosterone system, especially angiotensin II type 1a receptor (AT1aR and mineralocorticoid receptor (MR signaling, in left ventricular (LV dysfunction induced by diabetes mellitus (DM. METHODS AND RESULTS: DM was induced by intraperitoneal injection of streptozotocin (200 mg/kg BW in wild-type (WT or AT1aR knockout (KO male mice, and they were bred during 6 or 12 weeks. Some KO mice were administered the MR antagonist eplerenone (100 mg/kg body weight. At 6 weeks, LV diastolic function was impaired in WT-DM, but preserved in KO-DM. At that time point MR mRNA expression was upregulated, NADPH oxidase subunit (p47phox and glutathione peroxidase (GPx1 mRNA expression were upregulated, the staining intensities of LV tissue for 4-hydroxy-2-nonenal was stronger in immunohistochemistry, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL positive cells was increased, Bcl-2 protein expression was significantly downregulated, and the expression of SERCA2a and phosphorylated phospholamban was depressed in WT-DM, while these changes were not seen in KO-DM. At 12 weeks, however, these changes were also noted in KO-DM. Eplerenone arrested those changes. The plasma aldosterone concentration was elevated in WT-DM but not in KO-DM at 6 weeks. It showed 3.7-fold elevation at 12 weeks even in KO-DM, which suggests "aldosterone breakthrough" phenomenon. However, the aldosterone content in LV tissue was unchanged in KO-DM. CONCLUSIONS: DM induced diastolic dysfunction was observed even in KO at 12 weeks, which was ameliorated by minelarocorticoid receptor antagonist, eplerenone. AT1-independent MR activation in the LV might be responsible for the pathogenesis of diabetic cardiomyopathy.

  10. Activation of transient receptor potential ankyrin 1 by eugenol.

    Science.gov (United States)

    Chung, G; Im, S T; Kim, Y H; Jung, S J; Rhyu, M-R; Oh, S B

    2014-03-07

    Eugenol is a bioactive plant extract used as an analgesic agent in dentistry. The structural similarity of eugenol to cinnamaldehyde, an active ligand for transient receptor potential ankyrin 1 (TRPA1), suggests that eugenol might produce its effect via TRPA1, in addition to TRPV1 as we reported previously. In this study, we investigated the effect of eugenol on TRPA1, by fura-2-based calcium imaging and patch clamp recording in trigeminal ganglion neurons and in a heterologous expression system. As the result, eugenol induced robust calcium responses in rat trigeminal ganglion neurons that responded to a specific TRPA1 agonist, allyl isothiocyanate (AITC), and not to capsaicin. Capsazepine, a TRPV1 antagonist failed to inhibit eugenol-induced calcium responses in AITC-responding neurons. In addition, eugenol response was observed in trigeminal ganglion neurons from TRPV1 knockout mice and human embryonic kidney 293 cell lines that express human TRPA1, which was inhibited by TRPA1-specific antagonist HC-030031. Eugenol-evoked TRPA1 single channel activity and eugenol-induced TRPA1 currents were dose-dependent with EC50 of 261.5μM. In summary, these results demonstrate that the activation of TRPA1 might account for another molecular mechanism underlying the pharmacological action of eugenol.

  11. Affect and subsequent physical activity: An ambulatory assessment study examining the affect-activity association in a real-life context

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    Christina eNiermann

    2016-05-01

    Full Text Available Traditionally, cognitive, motivational and volitional determinants have been used to explain and predict health behaviors such as physical activity. Recently, the role of affect in influencing and regulating health behaviors received more attention. Affects as internal cues may automatically activate unconscious processes of behavior regulation. The aim of our study was to examine the association between affect and physical activity in daily life. In addition, we studied the influence of the habit of being physically active on this relationship.An ambulatory assessment study in 89 persons (33.7% male, 25 to 65 years, M=45.2, SD=8.1 was conducted. Affect was assessed in the afternoon on 5 weekdays using smartphones. Physical activity was measured continuously objectively using accelerometers and subjectively using smartphones in the evening. Habit strength was assessed at the beginning of the diary period. The outcomes were objectively and subjectively measured moderate-to-vigorous physical activity (MVPA performed after work. Multilevel regression models were used to analyze the association between affect and after work MVPA. In addition, the cross-level interaction of habit strength and affect on after work MVPA was tested.Positive affect was positively related to objectively measured and self-reported after work MVPA: the greater the positive affect the more time persons subsequently spent on MVPA. An inverse relationship was found for negative affect: the greater the negative affect the less time persons spent on MVPA. The cross-level interaction effect was significant only for objectively measured MVPA. A strong habit seems to strengthen both the positive influence of positive affect and the negative influence of negative affect.The results of this study confirm previous results and indicate that affect plays an important role for the regulation of physical activity behavior in daily life. The results for positive affect were consistent

  12. Pro-brain-derived neurotrophic factor inhibits GABAergic neurotransmission by activating endocytosis and repression of GABAA receptors.

    Science.gov (United States)

    Riffault, Baptiste; Medina, Igor; Dumon, Camille; Thalman, Carine; Ferrand, Nadine; Friedel, Perrine; Gaiarsa, Jean-Luc; Porcher, Christophe

    2014-10-01

    GABA is the canonical inhibitory neurotransmitter in the CNS. This inhibitory action is largely mediated by GABA type A receptors (GABAARs). Among the many factors controlling GABAergic transmission, brain-derived neurotrophic factor (BDNF) appears to play a major role in regulating synaptic inhibition. Recent findings have demonstrated that BDNF can be released as a precursor (proBDNF). Although the role of mature BDNF on GABAergic synaptogenesis and maintenance has been well studied, an important question still unanswered is whether secreted proBDNF might affect GABAergic neurotransmission. Here, we have used 14 d in vitro primary culture of hippocampal neurons and ex vivo preparations from rats to study the function of proBDNF in regulation of GABAAR trafficking and activity. We demonstrate that proBDNF impairs GABAergic transmission by the activation of two distinct pathways: (1) a RhoA-Rock-PTEN pathway that decreases the phosphorylation levels of GABAAR, thus affecting receptor function and triggering endocytosis and degradation of internalized receptors, and (2) a JAK-STAT-ICER pathway leading to the repression of GABAARs synthesis. These effects lead to the diminution of GABAergic synapses and are correlated with a decrease in GABAergic synaptic currents. These results revealed new functions for proBDNF-p75 neurotrophin receptor signaling pathway in the control of the efficacy of GABAergic synaptic activity by regulating the trafficking and synthesis of GABAARs at inhibitory synapses.

  13. Neuronal Heterotopias Affect the Activities of Distant Brain Areas and Lead to Behavioral Deficits.

    Science.gov (United States)

    Ishii, Kazuhiro; Kubo, Ken-ichiro; Endo, Toshihiro; Yoshida, Keitaro; Benner, Seico; Ito, Yukiko; Aizawa, Hidenori; Aramaki, Michihiko; Yamanaka, Akihiro; Tanaka, Kohichi; Takata, Norio; Tanaka, Kenji F; Mimura, Masaru; Tohyama, Chiharu; Kakeyama, Masaki; Nakajima, Kazunori

    2015-09-01

    Neuronal heterotopia refers to brain malformations resulting from deficits of neuronal migration. Individuals with heterotopias show a high incidence of neurological deficits, such as epilepsy. More recently, it has come to be recognized that focal heterotopias may also show a range of psychiatric problems, including cognitive and behavioral impairments. However, because focal heterotopias are not always located in the brain areas responsible for the symptoms, the causal relationship between the symptoms and heterotopias remains elusive. In this study, we showed that mice with focal heterotopias in the somatosensory cortex generated by in utero electroporation exhibited spatial working memory deficit and low competitive dominance behavior, which have been shown to be closely associated with the activity of the medial prefrontal cortex (mPFC) in rodents. Analysis of the mPFC activity revealed that the immediate-early gene expression was decreased and the local field potentials of the mPFC were altered in the mice with heterotopias compared with the control mice. Moreover, activation of these ectopic and overlying sister neurons using the DREADD (designer receptor exclusively activated by designer drug) system improved the working memory deficits. These findings suggest that cortical regions containing focal heterotopias can affect distant brain regions and give rise to behavioral abnormalities. Significance statement: Recent studies reported that patients with heterotopias have a variety of clinical symptoms, such as cognitive disturbance, psychiatric symptoms, and autistic behavior. However, the causal relationship between the symptoms and heterotopias remains elusive. Here we showed that mice with focal heterotopias in the somatosensory cortex generated by in utero electroporation exhibited behavioral deficits that have been shown to be associated with the mPFC activity in rodents. The existence of heterotopias indeed altered the neural activities of the mPFC, and

  14. HIV-1 activates macrophages independent of Toll-like receptors.

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    Joseph N Brown

    Full Text Available BACKGROUND: Macrophages provide an interface between innate and adaptive immunity and are important long-lived reservoirs for Human Immunodeficiency Virus Type-1 (HIV-1. Multiple genetic networks involved in regulating signal transduction cascades and immune responses in macrophages are coordinately modulated by HIV-1 infection. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate complex interrelated processes and to assemble an integrated view of activated signaling networks, a systems biology strategy was applied to genomic and proteomic responses by primary human macrophages over the course of HIV-1 infection. Macrophage responses, including cell cycle, calcium, apoptosis, mitogen-activated protein kinases (MAPK, and cytokines/chemokines, to HIV-1 were temporally regulated, in the absence of cell proliferation. In contrast, Toll-like receptor (TLR pathways remained unaltered by HIV-1, although TLRs 3, 4, 7, and 8 were expressed and responded to ligand stimulation in macrophages. HIV-1 failed to activate phosphorylation of IRAK-1 or IRF-3, modulate intracellular protein levels of Mx1, an interferon-stimulated gene, or stimulate secretion of TNF, IL-1beta, or IL-6. Activation of pathways other than TLR was inadequate to stimulate, via cross-talk mechanisms through molecular hubs, the production of proinflammatory cytokines typical of a TLR response. HIV-1 sensitized macrophage responses to TLR ligands, and the magnitude of viral priming was related to virus replication. CONCLUSIONS/SIGNIFICANCE: HIV-1 induced a primed, proinflammatory state, M1(HIV, which increased the responsiveness of macrophages to TLR ligands. HIV-1 might passively evade pattern recognition, actively inhibit or suppress recognition and signaling, or require dynamic interactions between macrophages and other cells, such as lymphocytes or endothelial cells. HIV-1 evasion of TLR recognition and simultaneous priming of macrophages may represent a strategy for viral survival, contribute

  15. REEPs are membrane shaping adapter proteins that modulate specific g protein-coupled receptor trafficking by affecting ER cargo capacity.

    Science.gov (United States)

    Björk, Susann; Hurt, Carl M; Ho, Vincent K; Angelotti, Timothy

    2013-01-01

    Receptor expression enhancing proteins (REEPs) were identified by their ability to enhance cell surface expression of a subset of G protein-coupled receptors (GPCRs), specifically GPCRs that have proven difficult to express in heterologous cell systems. Further analysis revealed that they belong to the Yip (Ypt-interacting protein) family and that some REEP subtypes affect ER structure. Yip family comparisons have established other potential roles for REEPs, including regulation of ER-Golgi transport and processing/neuronal localization of cargo proteins. However, these other potential REEP functions and the mechanism by which they selectively enhance GPCR cell surface expression have not been clarified. By utilizing several REEP family members (REEP1, REEP2, and REEP6) and model GPCRs (α2A and α2C adrenergic receptors), we examined REEP regulation of GPCR plasma membrane expression, intracellular processing, and trafficking. Using a combination of immunolocalization and biochemical methods, we demonstrated that this REEP subset is localized primarily to ER, but not plasma membranes. Single cell analysis demonstrated that these REEPs do not specifically enhance surface expression of all GPCRs, but affect ER cargo capacity of specific GPCRs and thus their surface expression. REEP co-expression with α2 adrenergic receptors (ARs) revealed that this REEP subset interacts with and alter glycosidic processing of α2C, but not α2A ARs, demonstrating selective interaction with cargo proteins. Specifically, these REEPs enhanced expression of and interacted with minimally/non-glycosylated forms of α2C ARs. Most importantly, expression of a mutant REEP1 allele (hereditary spastic paraplegia SPG31) lacking the carboxyl terminus led to loss of this interaction. Thus specific REEP isoforms have additional intracellular functions besides altering ER structure, such as enhancing ER cargo capacity, regulating ER-Golgi processing, and interacting with select cargo proteins

  16. Oleamide activates peroxisome proliferator-activated receptor gamma (PPARγ in vitro

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    Dionisi Mauro

    2012-05-01

    Full Text Available Abstract Background Oleamide (ODA is a fatty acid primary amide first identified in the cerebrospinal fluid of sleep-deprived cats, which exerts effects on vascular and neuronal tissues, with a variety of molecular targets including cannabinoid receptors and gap junctions. It has recently been reported to exert a hypolipidemic effect in hamsters. Here, we have investigated the nuclear receptor family of peroxisome proliferator-activated receptors (PPARs as potential targets for ODA action. Results Activation of PPARα, PPARβ and PPARγ was assessed using recombinant expression in Chinese hamster ovary cells with a luciferase reporter gene assay. Direct binding of ODA to the ligand binding domain of each of the three PPARs was monitored in a cell-free fluorescent ligand competition assay. A well-established assay of PPARγ activity, the differentiation of 3T3-L1 murine fibroblasts into adipocytes, was assessed using an Oil Red O uptake-based assay. ODA, at 10 and 50 μM, was able to transactivate PPARα, PPARβ and PPARγ receptors. ODA bound to the ligand binding domain of all three PPARs, although complete displacement of fluorescent ligand was only evident for PPARγ, at which an IC50 value of 38 μM was estimated. In 3T3-L1 cells, ODA, at 10 and 20 μM, induced adipogenesis. Conclusions We have, therefore, identified a novel site of action of ODA through PPAR nuclear receptors and shown how ODA should be considered as a weak PPARγ ligand in vitro.

  17. Improved Chemotherapeutic Activity by Morus alba Fruits through Immune Response of Toll-Like Receptor 4

    Directory of Open Access Journals (Sweden)

    Bo Yoon Chang

    2015-10-01

    Full Text Available Morus alba L. fruits have long been used in traditional medicine by many cultures. Their medicinal attributes include cardiovascular, hepatoprotective, neuroprotective and immunomodulatory actions. However, their mechanism of macrophage activation and anti-cancer effects remain unclear. The present study investigated the molecular mechanisms of immune stimulation and improved chemotherapeutic effect of M. alba L. fruit extract (MFE. MFE stimulated the production of cytokines, nitric oxide (NO and tumor necrosis factor-α (TNF-α and tumoricidal properties of macrophages. MFE activated macrophages through the mitogen-activated protein kinase (MAPKinase and nuclear factor-κB (NF-κB signaling pathways downstream from toll-like receptor (TLR 4. MFE was shown to exhibit cytotoxicity of CT26 cells via the activated macrophages, even though MFE did not directly affect CT26 cells. In a xenograft mouse model, MFE significantly enhanced anti-cancer activity combined with 5-fluorouracil and markedly promoted splenocyte proliferation, natural killer (NK cell activity, cytotoxic T lymphocyte (CTL activity and IFN-γ production. Immunoglobulin G (IgG antibody levels were significantly increased. These results indicate the indirect anti-cancer activity of MFE through improved immune response mediated by TLR4 signaling. M. alba L. fruit extract might be a potential anti-tumor immunomodulatory candidate chemotherapy agent.

  18. Improved Chemotherapeutic Activity by Morus alba Fruits through Immune Response of Toll-Like Receptor 4.

    Science.gov (United States)

    Chang, Bo Yoon; Kim, Seon Beom; Lee, Mi Kyeong; Park, Hyun; Kim, Sung Yeon

    2015-10-13

    Morus alba L. fruits have long been used in traditional medicine by many cultures. Their medicinal attributes include cardiovascular, hepatoprotective, neuroprotective and immunomodulatory actions. However, their mechanism of macrophage activation and anti-cancer effects remain unclear. The present study investigated the molecular mechanisms of immune stimulation and improved chemotherapeutic effect of M. alba L. fruit extract (MFE). MFE stimulated the production of cytokines, nitric oxide (NO) and tumor necrosis factor-α (TNF-α) and tumoricidal properties of macrophages. MFE activated macrophages through the mitogen-activated protein kinase (MAPKinase) and nuclear factor-κB (NF-κB) signaling pathways downstream from toll-like receptor (TLR) 4. MFE was shown to exhibit cytotoxicity of CT26 cells via the activated macrophages, even though MFE did not directly affect CT26 cells. In a xenograft mouse model, MFE significantly enhanced anti-cancer activity combined with 5-fluorouracil and markedly promoted splenocyte proliferation, natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) activity and IFN-γ production. Immunoglobulin G (IgG) antibody levels were significantly increased. These results indicate the indirect anti-cancer activity of MFE through improved immune response mediated by TLR4 signaling. M. alba L. fruit extract might be a potential anti-tumor immunomodulatory candidate chemotherapy agent.

  19. Astrocytic β2 Adrenergic Receptor Gene Deletion Affects Memory in Aged Mice

    Science.gov (United States)

    Jensen, Cathy Joanna; Demol, Frauke; Bauwens, Romy; Kooijman, Ron; Massie, Ann; Villers, Agnès; Ris, Laurence; De Keyser, Jacques

    2016-01-01

    In vitro and in vivo studies suggest that the astrocytic adrenergic signalling enhances glycogenolysis which provides energy to be transported to nearby cells and in the form of lactate. This energy source is important for motor and cognitive functioning. While it is suspected that the β2-adrenergic receptor on astrocytes might contribute to this energy balance, it has not yet been shown conclusively in vivo. Inducible astrocyte specific β2-adrenergic receptor knock-out mice were generated by crossing homozygous β2-adrenergic receptor floxed mice (Adrb2flox) and mice with heterozygous tamoxifen-inducible Cre recombinase-expression driven by the astrocyte specific L-glutamate/L-aspartate transporter promoter (GLAST-CreERT2). Assessments using the modified SHIRPA (SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment) test battery, swimming ability test, and accelerating rotarod test, performed at 1, 2 and 4 weeks, 6 and 12 months after tamoxifen (or vehicle) administration did not reveal any differences in physical health or motor functions between the knock-out mice and controls. However deficits were found in the cognitive ability of aged, but not young adult mice, reflected in impaired learning in the Morris Water Maze. Similarly, long-term potentiation (LTP) was impaired in hippocampal brain slices of aged knock-out mice maintained in low glucose media. Using microdialysis in cerebellar white matter we found no significant differences in extracellular lactate or glucose between the young adult knock-out mice and controls, although trends were detected. Our results suggest that β2-adrenergic receptor expression on astrocytes in mice may be important for maintaining cognitive health at advanced age, but is dispensable for motor function. PMID:27776147

  20. Mental rotation in intellectually gifted boys is affected by the androgen receptor CAG repeat polymorphism.

    Science.gov (United States)

    Durdiaková, Jaroslava; Lakatošová, Silvia; Kubranská, Aneta; Laznibatová, Jolana; Ficek, Andrej; Ostatníková, Daniela; Celec, Peter

    2013-08-01

    Testosterone was shown to organize brain and modulate cognitive functions. It is currently unknown whether mental rotation is also associated with prenatal testosterone exposure and testosterone-related genetic polymorphisms. The aim of our study was to analyze associations between mental rotation performance, the actual testosterone levels, the prenatal testosterone level (expressed as 2D:4D ratio) and the androgen receptor CAG repeat polymorphism in intellectually gifted boys. One hundred forty-seven boys aged 10-18 years with IQ>130 were enrolled. Saliva samples were collected and used for ELISA of actual levels of salivary testosterone. The 2D:4D finger length ratio as an indicator of prenatal testosterone was measured on both hands and averaged. Amthauer mental rotation test was used for the assessment of this spatial ability. The CAG repeat polymorphism in the androgen receptor gene was analyzed using PCR and capillary electrophoresis. Linear regression revealed that 2D:4D finger length ratio and the number of CAG repeats in the androgen receptor gene were associated with mental rotation. Actual levels of testosterone did not correlate significantly with mental rotation. Multivariate analysis of covariance revealed that after adjustment of age as a confounding variable, only the effect of the genetic polymorphism was significant. The results are in line with our previous genetic analysis of intellectually gifted boys showing the importance of CAG repeat polymorphism in the androgen receptor gene. Details of the interactions between androgen signaling, testosterone levels and its metabolism especially during the prenatal development of brain function remain to be elucidated.

  1. Advanced Glycation End Products Affect Osteoblast Proliferation and Function by Modulating Autophagy Via the Receptor of Advanced Glycation End Products/Raf Protein/Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase/Extracellular Signal-regulated Kinase (RAGE/Raf/MEK/ERK) Pathway.

    Science.gov (United States)

    Meng, Hong-Zheng; Zhang, Wei-Lin; Liu, Fei; Yang, Mao-Wei

    2015-11-20

    The interaction between advanced glycation end products (AGEs) and receptor of AGEs (RAGE) is associated with the development and progression of diabetes-associated osteoporosis, but the mechanisms involved are still poorly understood. In this study, we found that AGE-modified bovine serum albumin (AGE-BSA) induced a biphasic effect on the viability of hFOB1.19 cells; cell proliferation was stimulated after exposure to low dose AGE-BSA, but cell apoptosis was stimulated after exposure to high dose AGE-BSA. The low dose AGE-BSA facilitates proliferation of hFOB1.19 cells by concomitantly promoting autophagy, RAGE production, and the Raf/MEK/ERK signaling pathway activation. Furthermore, we investigated the effects of AGE-BSA on the function of hFOB1.19 cells. Interestingly, the results suggest that the short term effects of low dose AGE-BSA increase osteogenic function and decrease osteoclastogenic function, which are likely mediated by autophagy and the RAGE/Raf/MEK/ERK signal pathway. In contrast, with increased treatment time, the opposite effects were observed. Collectively, AGE-BSA had a biphasic effect on the viability of hFOB1.19 cells in vitro, which was determined by the concentration of AGE-BSA and treatment time. A low concentration of AGE-BSA activated the Raf/MEK/ERK signal pathway through the interaction with RAGE, induced autophagy, and regulated the proliferation and function of hFOB1.19 cells.

  2. Differential effects of exercise on brain opioid receptor binding and activation in rats.

    Science.gov (United States)

    Arida, Ricardo Mario; Gomes da Silva, Sérgio; de Almeida, Alexandre Aparecido; Cavalheiro, Esper Abrão; Zavala-Tecuapetla, Cecilia; Brand, Serge; Rocha, Luisa

    2015-01-01

    Physical exercise stimulates the release of endogenous opioid peptides supposed to be responsible for changes in mood, anxiety, and performance. Exercise alters sensitivity to these effects that modify the efficacy at the opioid receptor. Although there is evidence that relates exercise to neuropeptide expression in the brain, the effects of exercise on opioid receptor binding and signal transduction mechanisms downstream of these receptors have not been explored. Here, we characterized the binding and G protein activation of mu opioid receptor, kappa opioid receptor or delta opioid receptor in several brain regions following acute (7 days) and chronic (30 days) exercise. As regards short- (acute) or long-term effects (chronic) of exercise, overall, higher opioid receptor binding was observed in acute-exercise animals and the opposite was found in the chronic-exercise animals. The binding of [(35) S]GTPγS under basal conditions (absence of agonists) was elevated in sensorimotor cortex and hippocampus, an effect more evident after chronic exercise. Divergence of findings was observed for mu opioid receptor, kappa opioid receptor, and delta opioid receptor receptor activation in our study. Our results support existing evidence of opioid receptor binding and G protein activation occurring differentially in brain regions in response to diverse exercise stimuli. We characterized the binding and G protein activation of mu, kappa, and delta opioid receptors in several brain regions following acute (7 days) and chronic (30 days) exercise. Higher opioid receptor binding was observed in the acute exercise animal group and opposite findings in the chronic exercise group. Higher G protein activation under basal conditions was noted in rats submitted to chronic exercise, as visible in the depicted pseudo-color autoradiograms.

  3. Triclocarban mediates induction of xenobiotic metabolism through activation of the constitutive androstane receptor and the estrogen receptor alpha.

    Science.gov (United States)

    Yueh, Mei-Fei; Li, Tao; Evans, Ronald M; Hammock, Bruce; Tukey, Robert H

    2012-01-01

    Triclocarban (3,4,4'-trichlorocarbanilide, TCC) is used as a broad-based antimicrobial agent that is commonly added to personal hygiene products. Because of its extensive use in the health care industry and resistance to degradation in sewage treatment processes, TCC has become a significant waste product that is found in numerous environmental compartments where humans and wildlife can be exposed. While TCC has been linked to a range of health and environmental effects, few studies have been conducted linking exposure to TCC and induction of xenobiotic metabolism through regulation by environmental sensors such as the nuclear xenobiotic receptors (XenoRs). To identify the ability of TCC to activate xenobiotic sensors, we monitored XenoR activities in response to TCC treatment using luciferase-based reporter assays. Among the XenoRs in the reporter screening assay, TCC promotes both constitutive androstane receptor (CAR) and estrogen receptor alpha (ERα) activities. TCC treatment to hUGT1 mice resulted in induction of the UGT1A genes in liver. This induction was dependent upon the constitutive active/androstane receptor (CAR) because no induction occurred in hUGT1Car(-/-) mice. Induction of the UGT1A genes by TCC corresponded with induction of Cyp2b10, another CAR target gene. TCC was demonstrated to be a phenobarbital-like activator of CAR in receptor-based assays. While it has been suggested that TCC be classified as an endocrine disruptor, it activates ERα leading to induction of Cyp1b1 in female ovaries as well as in promoter activity. Activation of ERα by TCC in receptor-based assays also promotes induction of human CYP2B6. These observations demonstrate that TCC activates nuclear xenobiotic receptors CAR and ERα both in vivo and in vitro and might have the potential to alter normal physiological homeostasis. Activation of these xenobiotic-sensing receptors amplifies gene expression profiles that might represent a mechanistic base for potential human

  4. Increased leptin/leptin receptor pathway affects systemic and airway inflammation in COPD former smokers

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    Bruno A

    2011-05-01

    Full Text Available Andreina Bruno1, Marinella Alessi2, Simona Soresi2, Anna Bonanno1, Loredana Riccobono1, Angela Marina Montalbano1, Giusy Daniela Albano1, Mark Gjomarkaj1, Mirella Profita11Institute of Biomedicine and Molecular Immunology, Italian National Research Council, Palermo, Italy; 2Dipartimento Biomedico di Biomedicina Interna e Specialistica, University Palermo, ItalyBackground: Leptin, a hormone produced mainly by adipose tissue, regulates food intake and energy expenditure. It is involved in inflammatory diseases such as chronic obstructive pulmonary disease (COPD and its deficiency is associated with increased susceptibility to the infection. The leptin receptor is expressed in the lung and in the neutrophils.Methods: We measured the levels of leptin, tumor necrosis factor alpha (TNF-a and soluble form of intercellular adhesion molecule-1 (sICAM-1 in sputum and plasma from 27 smoker and former smoker patients with stable COPD using ELISA methods. Further we analyzed leptin and its receptor expression in sputum cells from 16 COPD patients using immunocytochemistry.Results: In plasma of COPD patients, leptin was inversely correlated with TNF-a and positively correlated with the patient weight, whereas the levels of sICAM-1 were positively correlated with TNF-a. In sputum of COPD patients leptin levels were correlated with forced expiratory volume in 1 second/forced vitality capacity. Additionally, increased levels of sputum leptin and TNF-a were observed in COPD former smokers rather than smokers. Further the expression of leptin receptor in sputum neutrophils was significantly higher in COPD former smokers than in smokers, and the expression of leptin and its receptor was positively correlated in neutrophils of COPD former smokers.Conclusion: Our findings suggest a role of leptin in the local and systemic inflammation of COPD and, taking into account the involvement of neutrophils in this inflammatory disease, describe a novel aspect of the leptin

  5. Identification of Modulators of the Nuclear Receptor Peroxisome Proliferator-Activated Receptor α (PPARα in a Mouse Liver Gene Expression Compendium.

    Directory of Open Access Journals (Sweden)

    Keiyu Oshida

    Full Text Available The nuclear receptor family member peroxisome proliferator-activated receptor α (PPARα is activated by therapeutic hypolipidemic drugs and environmentally-relevant chemicals to regulate genes involved in lipid transport and catabolism. Chronic activation of PPARα in rodents increases liver cancer incidence, whereas suppression of PPARα activity leads to hepatocellular steatosis. Analytical approaches were developed to identify biosets (i.e., gene expression differences between two conditions in a genomic database in which PPARα activity was altered. A gene expression signature of 131 PPARα-dependent genes was built using microarray profiles from the livers of wild-type and PPARα-null mice after exposure to three structurally diverse PPARα activators (WY-14,643, fenofibrate and perfluorohexane sulfonate. A fold-change rank-based test (Running Fisher’s test (p-value ≤ 10-4 was used to evaluate the similarity between the PPARα signature and a test set of 48 and 31 biosets positive or negative, respectively for PPARα activation; the test resulted in a balanced accuracy of 98%. The signature was then used to identify factors that activate or suppress PPARα in an annotated mouse liver/primary hepatocyte gene expression compendium of ~1850 biosets. In addition to the expected activation of PPARα by fibrate drugs, di(2-ethylhexyl phthalate, and perfluorinated compounds, PPARα was activated by benzofuran, galactosamine, and TCDD and suppressed by hepatotoxins acetaminophen, lipopolysaccharide, silicon dioxide nanoparticles, and trovafloxacin. Additional factors that activate (fasting, caloric restriction or suppress (infections PPARα were also identified. This study 1 developed methods useful for future screening of environmental chemicals, 2 identified chemicals that activate or suppress PPARα, and 3 identified factors including diets and infections that modulate PPARα activity and would be hypothesized to affect chemical

  6. Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity

    DEFF Research Database (Denmark)

    Holst, P J; Rosenkilde, M M; Manfra, D;

    2001-01-01

    ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein-coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi...... sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease. In addition, animals expressing a receptor that preserves chemokine binding and constitutive activity but that does...

  7. Timosaponin AIII induces antiplatelet and antithrombotic activity via Gq-mediated signaling by the thromboxane A2 receptor

    Science.gov (United States)

    Cong, Yue; Wang, Limei; Peng, Renjun; Zhao, Yang; Bai, Fan; Yang, Chao; Liu, Xiaolan; Wang, Daqian; Ma, Baiping; Cong, Yuwen

    2016-01-01

    The thromboxane (Tx) A2 pathway is a major contributor to the amplification of initial platelet activation and is therefore a key drug target. To identify potent small-molecule inhibitors of the thromboxane prostaglandin (TP) receptor, we screened a small steroidal saponin library using U46619-induced rat platelet aggregation assays. Timosaponin AIII (TAIII) was identified as a potent inhibitor of U46619-induced rat platelet aggregation and exhibited superior selectivity for the TP receptor versus other G protein-coupled receptors and a PKC activator. TAIII inhibited U46619-induced rat platelet aggregation independent of increases in cAMP and cGMP and the inhibition of TxA2 production. Both PKC and PLC activators restored TAIII-inhibited platelet aggregation, whereas TAIII did not inhibit platelet aggregation induced by co-activation of the G12/13 and Gz pathways. Furthermore, TAIII did not affect the platelet shape change or ROCK2 phosphorylation evoked by low-dose U46619. In vivo, TAIII prolonged tail bleeding time, reduced the mortality of animals with acute pulmonary thromboembolism and significantly reduced venous thrombus weight. Our study suggests that TAIII, by preferentially targeting Gq-mediated PLC/PKC signaling from the TP receptor, induces stronger in vitro antiplatelet activity and in vivo antithrombotic effects and may be an excellent candidate for the treatment of thrombotic disorders. PMID:27934923

  8. Novel function of perforin in negatively regulating CD4+T cell activation by affecting calcium signaling

    Institute of Scientific and Technical Information of China (English)

    Enguang Bi; Kairui Mao; Jia Zou; Yuhan Zheng; Bing Sun; Chunjian Huang; Yu Hu; Xiaodong Wu; Weiwen Deng; Guomei Lin; Zhiduo Liu; Lin Tian; Shuhui Sun

    2009-01-01

    Perforin is a pore-forming protein engaged mainly in mediating target T cell death and is employed by cytotoxic Tlymphocytes (CTLs) and natural killer cells. However, whether it also plays a role in conventional CD4+ T cell func-tion remains unclear. Here we report that in perforin-deficient (PKO) mice, CD4+ T cells are hyperproliferative in response to T cell receptor (TCR) stimulation. This feature of hyperproliferation is accompanied by the enhancement both in cell division and in IL-2 secretion. It seems that the perforin deficiency does not influence T cell development in thymus spleen and lymph node. In vivo, perforin deficiency results in increased antigen-specific T cell prolifera-tion and antibody production. Furthermore, PKO mice are more susceptible to experimental autoimmune uveitis. To address the molecular mechanism, we found that after TCR stimulation, CD44 T cells from PKO mice display an increased intracellular calcium flux and subsequently enhance activation of transcription factor NFATI. Our results indicate that perforin plays a negative role in regulating CD4+ T cell activation and immune response by affecting TCR-dependent Ca2+ signaling.

  9. Biased signaling by peptide agonists of protease activated receptor 2.

    Science.gov (United States)

    Jiang, Yuhong; Yau, Mei-Kwan; Kok, W Mei; Lim, Junxian; Wu, Kai-Chen; Liu, Ligong; Hill, Timothy A; Suen, Jacky Y; Fairlie, David P

    2017-02-07

    Protease activated receptor 2 (PAR2) is associated with metabolism, obesity, inflammatory, respiratory and gastrointestinal disorders, pain, cancer and other diseases. The extracellular N-terminus of PAR2 is a common target for multiple proteases, which cleave it at different sites to generate different N-termini that activate different PAR2-mediated intracellular signaling pathways. There are no synthetic PAR2 ligands that reproduce the same signaling profiles and potencies as proteases. Structure-activity relationships here for 26 compounds spanned a signaling bias over 3 log units, culminating in three small ligands as biased agonist tools for interrogating PAR2 functions. DF253 (2f-LAAAAI-NH2) triggered PAR2-mediated calcium release (EC50 2 μM) but not ERK1/2 phosphorylation (EC50 > 100 μM) in CHO cells transfected with hPAR2. AY77 (Isox-Cha-Chg-NH2) was a more potent calcium-biased agonist (EC50 40 nM, Ca2+; EC50 2 μM, ERK1/2), while its analogue AY254 (Isox-Cha-Chg-A-R-NH2) was an ERK-biased agonist (EC50 2 nM, ERK1/2; EC50 80 nM, Ca2+). Signaling bias led to different functional responses in human colorectal carcinoma cells (HT29). AY254, but not AY77 or DF253, attenuated cytokine-induced caspase 3/8 activation, promoted scratch-wound healing and induced IL-8 secretion, all via PAR2-ERK1/2 signaling. Different ligand components were responsible for different PAR2 signaling and functions, clues that can potentially lead to drugs that modulate different pathway-selective cellular and physiological responses.

  10. Reconstituted B cell receptor signaling reveals carbohydrate-dependent mode of activation

    OpenAIRE

    2016-01-01

    Activation of immune cells (but not B cells) with lectins is widely known. We used the structurally defined interaction between influenza hemagglutinin (HA) and its cell surface receptor sialic acid (SA) to identify a B cell receptor (BCR) activation modality that proceeded through non-cognate interactions with antigen. Using a new approach to reconstitute antigen-receptor interactions in a human reporter B cell line, we found that sequence-defined BCRs from the human germline repertoire coul...

  11. How Do Sociodemographics and Activity Participations Affect Activity-Travel? Comparative Study between Women and Men

    Directory of Open Access Journals (Sweden)

    Min Yang

    2014-01-01

    Full Text Available Activity-travel behaviors of women and men are different because they have different social and household responsibilities. However, studies concerning gender differences are mainly limited in developed countries. This paper concentrates on gender role-based differences in activity-travel behavior in a typical developing country, namely, China. Using data from 3656 cases collected through surveys conducted in Shangyu, data processing, method choice, and descriptive analysis were conducted. Binary and ordered logistic regression models segmented by gender were developed to evaluate the mechanism through which individual sociodemographics, household characteristics, and activity participations affect the number of trip chain types and activities for women and men. The results show that women aged 30 to 50 perform less subsistence activities. However, the difference between the different age groups of men is not as significant. In addition, men with bicycles and electric bicycles have more subsistence and maintenance activities, whereas women do not have these attributes. Moreover, women with children under schooling age make more maintenance trip chains but less leisure trip chains and activities, whereas men are free from this influence. Furthermore, both women and men perform more subsistence activities if the duration increases, and men have less influences than women do.

  12. Serotonergic activation of 5HT1A and 5HT2 receptors modulates sexually dimorphic communication signals in the weakly electric fish Apteronotus leptorhynchus.

    Science.gov (United States)

    Smith, G Troy; Combs, Nicole

    2008-06-01

    Serotonin modulates agonistic and reproductive behavior across vertebrate species. 5HT(1A) and 5HT(1B) receptors mediate many serotonergic effects on social behavior, but other receptors, including 5HT(2) receptors, may also contribute. We investigated serotonergic regulation of electrocommunication signals in the weakly electric fish Apteronotus leptorhynchus. During social interactions, these fish modulate their electric organ discharges (EODs) to produce signals known as chirps. Males chirp more than females and produce two chirp types. Males produce high-frequency chirps as courtship signals; whereas both sexes produce low-frequency chirps during same-sex interactions. Serotonergic innervation of the prepacemaker nucleus, which controls chirping, is more robust in females than males. Serotonin inhibits chirping and may contribute to sexual dimorphism and individual variation in chirping. We elicited chirps with EOD playbacks and pharmacologically manipulated serotonin receptors to determine which receptors regulated chirping. We also asked whether serotonin receptor activation generally modulated chirping or more specifically targeted particular chirp types. Agonists and antagonists of 5HT(1B/1D) receptors (CP-94253 and GR-125743) did not affect chirping. The 5HT(1A) receptor agonist 8OH-DPAT specifically increased production of high-frequency chirps. The 5HT(2) receptor agonist DOI decreased chirping. Receptor antagonists (WAY-100635 and MDL-11939) opposed the effects of their corresponding agonists. These results suggest that serotonergic inhibition of chirping may be mediated by 5HT(2) receptors, but that serotonergic activation of 5HT(1A) receptors specifically increases the production of high-frequency chirps. The enhancement of chirping by 5HT(1A) receptors may result from interactions with cortisol and/or arginine vasotocin, which similarly enhance chirping and are influenced by 5HT(1A) activity in other systems.

  13. [The effect of goal framing on the activation of affective representations].

    Science.gov (United States)

    Takehashi, Hiroki; Karasawa, Kaori

    2007-10-01

    Guided by regulatory focus theory, this study examined the effects of goal framing on the subjective experience of affect and the accessibility of affective representations. Study I examined lay persons' beliefs concerning the relationship between goal framing and certain kinds of affective experiences. The results indicated that a promotion focus was associated with happiness and disappointment, whereas a prevention focus was associated with relaxation and tension. Study 2 examined the effect of goal framing on the activation of affective representations, and found that a promotion focus activated both gain-related representations (happy and disappointment) and loss-related representations (relaxation and tension), whereas a prevention focus activated only loss-related representations. These results suggest that goal framing activates particular affective representations, and the activated affective representations may influence the interpretation of positive or negative experiences. The discussion considered the function of the activation of affective representations as a mediator between goal framing and its cognitive and behavioral consequences.

  14. CB1 receptor deficiency decreases wheel-running activity: consequences on emotional behaviours and hippocampal neurogenesis.

    Science.gov (United States)

    Dubreucq, Sarah; Koehl, Muriel; Abrous, Djoher N; Marsicano, Giovanni; Chaouloff, Francis

    2010-07-01

    Chronic voluntary wheel-running activity has been reported to hypersensitise central CB1 receptors in mice. On the other hand, pharmacological findings suggest that the CB1 receptor could be involved in wheel-running behaviour and in running-induced neurogenesis in the hippocampus. We analysed wheel-running behaviour for 6 weeks and measured its consequences on hippocampal neurogenesis in CB1 knockout (CB1(-/-)) animals, compared to wild-type (CB1(+/+)) littermates. Because wheel running has been shown to affect locomotor reactivity in novel environments, memory for aversive events and depression-like behaviours, we also assessed these behaviours in control and running CB1(+/+) and CB1(-/-) mice. When compared with running CB1(+/+) mice, the distance covered weekly by CB1(-/-) mice was decreased by 30-40%, an observation accounted for by decreased time spent and maximal velocity on the wheels. Analyses of running distances with respect to the light/dark cycle revealed that mutant covered less distance throughout both the inactive and the active phases of that cycle. Locomotion in an activity cage, exploration in an open field, and immobility time in the forced swim test proved insensitive to chronic wheel running in either genotype. Wheel running, per se, did not influence the expression and extinction of cued fear memory but counteracted in a time-dependent manner the deficiency of extinction measured in CB1(-/-) mice. Hippocampal neurogenesis, assessed by doublecortin labelling of immature neurons in the dentate gyrus, was lowered by 40% in control CB1(-/-) mice, compared to control CB1(+/+) mice. Although CB1(-/-) mice ran less than their wild-type littermates, the 6-week running protocol increased neurogenesis to similar extents (37-39%) in both genotypes. This study suggests that mouse CB1 receptors control wheel running but not its neurogenic consequences in the hippocampus.

  15. Dynamic alterations of serotonergic metabolism and receptors during social isolation of low- and high-active mice.

    Science.gov (United States)

    Rilke, O; Freier, D; Jähkel, M; Oehler, J

    1998-04-01

    Alterations induced by social isolation (1 day to 18 weeks) in low- and high-active mice (LAM and HAM) were studied in respect to serotonin metabolism, [3H]-8-OH-DPAT binding of presynaptic (midbrain), postsynaptic (hippocampus) 5-HT1A receptors and [3H]-ketanserin binding of cortical 5-HT2A receptors. Individual housing of mice was associated with reduction of serotonin metabolism, depending on isolation time and brain structure. Whereas a transient decrease in the striatum and cortex was detected between 1 week and 6 weeks, reduction of cerebellar and hippocampal serotonin metabolism was found later (12-18 weeks). Serotonergic systems of HAM were found to be more reactive to environmental disturbances, and their serotonin metabolism was more affected by social isolation. Isolation-induced upregulation of cortical 5-HT2A receptors was measured only in HAM. Densities of postsynaptic 5-HT1A receptors in the hippocampus did differ either in grouped or isolated mice. However, there were significant differences in hippocampal 5-HT1A receptor affinity, especially between 1 day and 3 weeks. Transient downregulation of presynaptic 5-HT1A receptors in the midbrain was found in isolated mice between 3 and 6 weeks. These results are discussed in terms of interactions between serotonergic alterations and isolation-induced aggression.

  16. Xanthurenic Acid Activates mGlu2/3 Metabotropic Glutamate Receptors and is a Potential Trait Marker for Schizophrenia.

    Science.gov (United States)

    Fazio, Francesco; Lionetto, Luana; Curto, Martina; Iacovelli, Luisa; Cavallari, Michele; Zappulla, Cristina; Ulivieri, Martina; Napoletano, Flavia; Capi, Matilde; Corigliano, Valentina; Scaccianoce, Sergio; Caruso, Alessandra; Miele, Jessica; De Fusco, Antonio; Di Menna, Luisa; Comparelli, Anna; De Carolis, Antonella; Gradini, Roberto; Nisticò, Robert; De Blasi, Antonio; Girardi, Paolo; Bruno, Valeria; Battaglia, Giuseppe; Nicoletti, Ferdinando; Simmaco, Maurizio

    2015-12-08

    The kynurenine pathway of tryptophan metabolism has been implicated in the pathophysiology of psychiatric disorders, including schizophrenia. We report here that the kynurenine metabolite, xanturenic acid (XA), interacts with, and activates mGlu2 and mGlu3 metabotropic glutamate receptors in heterologous expression systems. However, the molecular nature of this interaction is unknown, and our data cannot exclude that XA acts primarily on other targets, such as the vesicular glutamate transporter, in the CNS. Systemic administration of XA in mice produced antipsychotic-like effects in the MK-801-induced model of hyperactivity. This effect required the presence of mGlu2 receptors and was abrogated by the preferential mGlu2/3 receptor antagonist, LY341495. Because the mGlu2 receptor is a potential drug target in the treatment of schizophrenia, we decided to measure serum levels of XA and other kynurenine metabolites in patients affected by schizophrenia. Serum XA levels were largely reduced in a large cohort of patients affected by schizophrenia, and, in patients with first-episode schizophrenia, levels remained low after 12 months of antipsychotic medication. As opposed to other kynurenine metabolites, XA levels were also significantly reduced in first-degree relatives of patients affected by schizophrenia. We suggest that lowered serum XA levels might represent a novel trait marker for schizophrenia.

  17. Activation of Cannabinoid Receptor 2 Enhances Osteogenic Differentiation of Bone Marrow Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Yong-Xin Sun

    2015-01-01

    Full Text Available Bone marrow derived mesenchymal stem cells (BM-MSCs are considered as the most promising cells source for bone engineering. Cannabinoid (CB receptors play important roles in bone mass turnover. The aim of this study is to test if activation of CB2 receptor by chemical agonist could enhance the osteogenic differentiation and mineralization in bone BM-MSCs. Alkaline phosphatase (ALP activity staining and real time PCR were performed to test the osteogenic differentiation. Alizarin red staining was carried out to examine the mineralization. Small interference RNA (siRNA was used to study the role of CB2 receptor in osteogenic differentiation. Results showed activation of CB2 receptor increased ALP activity, promoted expression of osteogenic genes, and enhanced deposition of calcium in extracellular matrix. Knockdown of CB2 receptor by siRNA inhibited ALP activity and mineralization. Results of immunofluorescent staining showed that phosphorylation of p38 MAP kinase is reduced by knocking down of CB2 receptor. Finally, bone marrow samples demonstrated that expression of CB2 receptor is much lower in osteoporotic patients than in healthy donors. Taken together, data from this study suggested that activation of CB2 receptor plays important role in osteogenic differentiation of BM-MSCs. Lack of CB2 receptor may be related to osteoporosis.

  18. Determinants affecting physical activity levels in animal models

    Science.gov (United States)

    Tou, Janet C L.; Wade, Charles E.

    2002-01-01

    Weight control is dependent on energy balance. Reduced energy expenditure (EE) associated with decreased physical activity is suggested to be a major underlying cause in the increasing prevalence of weight gain and obesity. Therefore, a better understanding of the biological determinants involved in the regulation of physical activity is essential. To facilitate interpretation in humans, it is helpful to consider the evidence from animal studies. This review focuses on animal studies examining the biological determinants influencing activity and potential implications to human. It appears that physical activity is influenced by a number of parameters. However, regardless of the parameter involved, body weight appears to play an underlying role in the regulation of activity. Furthermore, the regulation of activity associated with body weight appears to occur only after the animal achieves a critical weight. This suggests that activity levels are a consequence rather than a contributor to weight control. However, the existence of an inverse weight-activity relationship remains inconclusive. Confounding the results are the multifactorial nature of physical activity and the lack of appropriate measuring devices. Furthermore, many determinants of body weight are closely interlocked, making it difficult to determine whether a single, combination, or interaction of factors is important for the regulation of activity. For example, diet-induced obesity, aging, lesions to the ventral medial hypothalamus, and genetics all produce hypoactivity. Providing a better understanding of the biological determinants involved in the regulation of activity has important implications for the development of strategies for the prevention of weight gain leading to obesity and subsequent morbidity and mortality in the human population.

  19. [5-HT1A/5-HT7 receptor interplay: Chronic activation of 5-HT7 receptors decreases the functional activity of 5-HT1A receptor and its сontent in the mouse brain].

    Science.gov (United States)

    Kondaurova, E M; Bazovkina, D V; Naumenko, V S

    2017-01-01

    Serotonin receptors 5-HT1A and 5-HT7 are involved in the development of various psychopathologies. Some data indicate that there is an interplay between 5-HT1A 5-HT7 receptors that could be implicated in the regulation of their function. This work analyzed the effects of chronic 5-HT7 activation on the functional activity of 5-HT7 and 5-HT1A receptors, on the corresponding protein levels, and on the expression of genes encoding 5-HT7 and 5-HT1A receptors in the mouse brain. Chronic administration of the 5-HT7 selective agonist LP44 (20.5 nmol, i.c.v., 14 days) produced considerable desensitization of both 5-HT7 and 5-HT1A receptors. In LP44-treated mice, the hypothermic responses mediated by both 5-HT7 and 5-HT1A receptors were attenuated. Moreover, the levels of 5-HT1A receptor protein in the midbrain and the frontal cortex of LP44-treated mice were significantly decreased. However, the brain levels of 5-HT7 receptor protein did not differ between LP44-treated and control mice. Chronic LP44 treatment did not alter the expression of the 5-HT7 and 5-HT1A receptor genes in all investigated brain structure. These data suggest that 5-HT7 receptors participate in the posttranscriptional regulation of the 5-HT1A receptors functioning.

  20. Stereostructure-activity studies on agonists at the AMPA and kainate subtypes of ionotropic glutamate receptors

    DEFF Research Database (Denmark)

    Johansen, Tommy N; Greenwood, Jeremy R; Frydenvang, Karla Andrea;

    2003-01-01

    -methyl-4-isoxazolyl)propionic acid (AMPA) receptor subtype of ionotropic Glu receptors in the presence or absence of an agonist has provided important information about ligand-receptor interaction mechanisms. The availability of these binding domain crystal structures has formed the basis for rational...... design of ligands, especially for the AMPA and kainate subtypes of ionotropic Glu receptors. This mini-review will focus on structure-activity relationships on AMPA and kainate receptor agonists with special emphasis on stereochemical and three-dimensional aspects....

  1. NMDA receptor activation regulates sociability by its effect on mTOR signaling activity.

    Science.gov (United States)

    Burket, Jessica A; Benson, Andrew D; Tang, Amy H; Deutsch, Stephen I

    2015-07-01

    Tuberous Sclerosis Complex is one example of a syndromic form of autism spectrum disorder associated with disinhibited activity of mTORC1 in neurons (e.g., cerebellar Purkinje cells). mTORC1 is a complex protein possessing serine/threonine kinase activity and a key downstream molecule in a signaling cascade beginning at the cell surface with the transduction of neurotransmitters (e.g., glutamate and acetylcholine) and nerve growth factors (e.g., Brain-Derived Neurotrophic Factor). Interestingly, the severity of the intellectual disability in Tuberous Sclerosis Complex may relate more to this metabolic disturbance (i.e., overactivity of mTOR signaling) than the density of cortical tubers. Several recent reports showed that rapamycin, an inhibitor of mTORC1, improved sociability and other symptoms in mouse models of Tuberous Sclerosis Complex and autism spectrum disorder, consistent with mTORC1 overactivity playing an important pathogenic role. NMDA receptor activation may also dampen mTORC1 activity by at least two possible mechanisms: regulating intraneuronal accumulation of arginine and the phosphorylation status of a specific extracellular signal regulating kinase (i.e., ERK1/2), both of which are "drivers" of mTORC1 activity. Conceivably, the prosocial effects of targeting the NMDA receptor with agonists in mouse models of autism spectrum disorders result from their ability to dampen mTORC1 activity in neurons. Strategies for dampening mTORC1 overactivity by NMDA receptor activation may be preferred to its direct inhibition in chronic neurodevelopmental disorders, such as autism spectrum disorders.

  2. Prostate stem cell antigen interacts with nicotinic acetylcholine receptors and is affected in Alzheimer's disease

    DEFF Research Database (Denmark)

    Jensen, Majbrit Myrup; Mikkelsen, Jens D.; Arvaniti, Maria

    2015-01-01

    Alzheimer's disease (AD) is a neurodegenerative disorder involving impaired cholinergic neurotransmission and dysregulation of nicotinic acetylcholine receptors (nAChRs). Ly-6/neurotoxin (Lynx) proteins have been shown to modulate cognition and neural plasticity by binding to nAChR subtypes...... and modulating their function. Hence, changes in nAChR regulatory proteins such as Lynx proteins could underlie the dysregulation of nAChRs in AD. Using Western blotting, we detected bands corresponding to the Lynx proteins prostate stem cell antigen (PSCA) and Lypd6 in human cortex indicating that both proteins...

  3. Activation of toll-like receptors and dendritic cells by a broad range of bacterial molecules

    NARCIS (Netherlands)

    Boele, L.C.L.; Bajramovic, J.J.; Vries, A.M.M.B.C. de; Voskamp-Visser, I.A.I.; Kaman, W.E.; Kleij, D. van der

    2009-01-01

    Activation of pattern recognition receptors such as Toll-like receptors (TLRs) by pathogens leads to activation and maturation of dendritic cells (DC), which orchestrate the development of the adaptive immune response. To create an overview of the effects of a broad range of pathogenic bacteria, the

  4. Plasma soluble urokinase plasminogen activator receptor in children with urinary tract infection

    DEFF Research Database (Denmark)

    Wittenhagen, Per; Andersen, Jesper Brandt; Hansen, Anita

    2011-01-01

    In this prospective study we investigated the role of plasma levels of soluble urokinase plasminogen activator receptor (suPAR) in children with urinary tract infection.......In this prospective study we investigated the role of plasma levels of soluble urokinase plasminogen activator receptor (suPAR) in children with urinary tract infection....

  5. Peroxisome proliferators-activated receptor (PPAR) regulation in cardiac metabolism and disease

    NARCIS (Netherlands)

    el Azzouzi, H.

    2009-01-01

    Peroxisome proliferators-activated receptors (PPARs) are members of the nuclear receptor family of ligand activated transcription factors and consist of the three isoforms, PPAR, PPAR/ and PPAR. Considerable evidence has established the importance of PPARs in myocardial lipid homeostasis and car

  6. Experimental conditions affecting functional comparison of highly active glutathione transferases.

    Science.gov (United States)

    Fedulova, Natalia; Mannervik, Bengt

    2011-06-01

    Glutathione transferases (GSTs, EC 2.5.1.18) possess multiple functions and have potential applications in biotechnology. Direct evidence of underestimation of activity of human GST A3-3 and porcine GST A2-2 measured at submicromolar enzyme concentrations is reported here for the first time. The combination of time-dependent and enzyme concentration-dependent loss of activity and the choice of the organic solvent for substrates were found to cause irreproducibility of activity measurements of GSTs. These effects contribute to high variability of activity values of porcine GST A2-2 and human Alpha-class GSTs reported in the literature. Adsorption of GSTs to surfaces was found to be the main explanation of the observed phenomena. Several approaches to improved functional comparison of highly active GSTs are proposed.

  7. Intolerance of uncertainty correlates with insula activation during affective ambiguity

    OpenAIRE

    Simmons, Alan; Matthews, Scott C.; Paulus, Martin P; Stein, Murray B.

    2007-01-01

    Intolerance of uncertainty (IU), or the increased affective response to situations with uncertain outcomes, is an important component process of anxiety disorders. Increased IU is observed in panic disorder (PD), obsessive compulsive disorder (OCD) and generalized anxiety disorder (GAD), and is thought to relate to dysfunctional behaviors and thought patterns in these disorders. Identifying what brain systems are associated with IU would contribute to a comprehensive model of anxiety processi...

  8. SorLA Controls Neurotrophic Activity by Sorting of GDNF and Its Receptors GFRα1 and RET

    DEFF Research Database (Denmark)

    Glerup, Simon; Lume, Maria; Olsen, Ditte;

    2013-01-01

    Glial cell-line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor that has reached clinical trials for Parkinson's disease. GDNF binds to its coreceptor GFRα1 and signals through the transmembrane receptor tyrosine kinase RET, or RET independently through NCAM or syndecan-3....... Whereas the GDNF signaling cascades are well described, cellular turnover and trafficking of GDNF and its receptors remain poorly characterized. Here, we find that SorLA acts as sorting receptor for the GDNF/GFRα1 complex, directing it from the cell surface to endosomes. Through this mechanism, GDNF...... is targeted to lysosomes and degraded while GFRα1 recycles, creating an efficient GDNF clearance pathway. The SorLA/GFRα1 complex further targets RET for endocytosis but not for degradation, affecting GDNF-induced neurotrophic activities. SorLA-deficient mice display elevated GDNF levels, altered dopaminergic...

  9. In vitro inhibition of protease-activated receptors 1, 2 and 4 demonstrates that these receptors are not involved in an Acanthamoeba castellanii keratitis isolate-mediated disruption of the human brain microvascular endothelial cells.

    Science.gov (United States)

    Iqbal, Junaid; Naeem, Komal; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2014-11-01

    Granulomatous amoebic encephalitis is a rare but serious human disease leading almost always to death. The pathophysiology of amoebic encephalitis is better understood, while events leading to the constitution of brain infection are largely unknown. Traversal of the blood-brain barrier is a key step in amoebae invasion of the central nervous system and facilitated by amoebic extracellular proteases. By using specific inhibitors of protease-activated receptors 1, 2 and 4, here we studied the role of these host receptors in Acanthamoeba castellanii-mediated damage to human brain microvasculature endothelial cells (HBMEC), which constitute the blood-brain barrier. The primary HBMEC were incubated with A. castellanii-conditioned medium in the presence or absence of FR-171113 (selective inhibitor of protease-activated receptor 1), FSLLRY-NH2 (inhibitor of protease-activated receptor 2), and tcY-NH2 (inhibitor of protease-activated receptor 4). The HBMEC monolayer disruptions were assessed by microscopy using Eosin staining, while host cell cytotoxicity was determined by measuring the release of cytoplasmic lactate dehydrogenase. Zymographic assays were performed to determine the effects of inhibitors of protease-activated receptors on the extracellular proteolytic activities of A. castellanii. A. castellanii-conditioned medium produced severe HBMEC monolayer disruptions within 60 min. The selective inhibitors of protease-activated receptors tested did not affect HBMEC monolayer disruptions. On the contrary, pre-treatment of A. castellanii-conditioned medium with phenylmethylsulfonyl fluoride, a serine protease inhibitor, or heating for 10 min at 95°C abolished HBMEC monolayer disruptions. Additionally, inhibitors of protease-activated receptors tested, failed to block A. castellanii-mediated HBMEC cytotoxicity and did not affect extracellular proteolytic activities of A. castellanii. Protease-activated receptors 1, 2 and 4 do not appear to play a role in A. castellanii

  10. Sampling frequency affects ActiGraph activity counts

    DEFF Research Database (Denmark)

    Brønd, Jan Christian; Arvidsson, Daniel

    in Matlab and sampled at frequencies of 30-100 Hz. Also, acceleration signals during indoor walking and running were sampled at 30 Hz using the ActiGraph GT3X and resampled in Matlab to frequencies of 40-100 Hz. All data was processed with the ActiLife software.Results: Acceleration frequencies between 5....... The difference increased with increasing activity intensity, with up to 1000 counts per minute at fast running.Discussion & conclusions: Activity counts from vigorous physical activity is highly attenuated with the ActiLife software. High frequency movement and noise information escape the bandpass filter...

  11. Agonist-biased signaling via proteinase activated receptor-2: differential activation of calcium and mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Ramachandran, Rithwik; Mihara, Koichiro; Mathur, Maneesh; Rochdi, Moulay Driss; Bouvier, Michel; Defea, Kathryn; Hollenberg, Morley D

    2009-10-01

    We evaluated the ability of different trypsin-revealed tethered ligand (TL) sequences of rat proteinase-activated receptor 2 (rPAR(2)) and the corresponding soluble TL-derived agonist peptides to trigger agonist-biased signaling. To do so, we mutated the proteolytically revealed TL sequence of rPAR(2) and examined the impact on stimulating intracellular calcium transients and mitogen-activated protein (MAP) kinase. The TL receptor mutants, rPAR(2)-Leu(37)Ser(38), rPAR(2)-Ala(37-38), and rPAR(2)-Ala(39-42) were compared with the trypsin-revealed wild-type rPAR(2) TL sequence, S(37)LIGRL(42)-. Upon trypsin activation, all constructs stimulated MAP kinase signaling, but only the wt-rPAR(2) and rPAR(2)-Ala(39-42) triggered calcium signaling. Furthermore, the TL-derived synthetic peptide SLAAAA-NH2 failed to cause PAR(2)-mediated calcium signaling but did activate MAP kinase, whereas SLIGRL-NH2 triggered both calcium and MAP kinase signaling by all receptors. The peptides AAIGRL-NH2 and LSIGRL-NH2 triggered neither calcium nor MAP kinase signals. Neither rPAR(2)-Ala(37-38) nor rPAR(2)-Leu(37)Ser(38) constructs recruited beta-arrestins-1 or -2 in response to trypsin stimulation, whereas both beta-arrestins were recruited to these mutants by SLIGRL-NH2. The lack of trypsin-triggered beta-arrestin interactions correlated with impaired trypsin-activated TL-mutant receptor internalization. Trypsin-stimulated MAP kinase activation by the TL-mutated receptors was not blocked by inhibitors of Galpha(i) (pertussis toxin), Galpha(q) [N-cyclohexyl-1-(2,4-dichlorophenyl)-1,4-dihydro-6-methylindeno[1,2-c]pyrazole-3-carboxamide (GP2A)], Src kinase [4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]-pyrimidine (PP1)], or the epidermal growth factor (EGF) receptor [4-(3'-chloroanilino)-6,7-dimethoxy-quinazoline (AG1478)], but was inhibited by the Rho-kinase inhibitor (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide, 2HCl (Y27362). The data indicate that the

  12. Oxidative Activity of Heated Coal Affected by Antypirogens

    Science.gov (United States)

    Torosyan, V. F.; Torosyan, E. S.; Borovikov, I. F.; Yakutova, V. A.

    2016-04-01

    The effect of antypirogens on chemical activity of heated coal is studied. It is proved that ammonium sulfate, calcium phosphate, calcium chloride, calcium nitrate and acid fluoride are the most effective antypirogens.

  13. Phytoceramide and sphingoid bases derived from brewer's yeast Saccharomyces pastorianus activate peroxisome proliferator-activated receptors

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    Mitsutake Susumu

    2011-08-01

    Full Text Available Abstract Background Peroxisome proliferator-activated receptors (PPARs are ligand-activated transcription factors that regulate lipid and glucose metabolism. PPARα is highly expressed in the liver and controls genes involved in lipid catabolism. We previously reported that synthetic sphingolipid analogs, part of which contains shorter-length fatty acid chains than natural sphingolipids, stimulated the transcriptional activities of PPARs. Sphingosine and dihydrosphingosine (DHS are abundant sphingoid bases, and ceramide and dihydroceramide are major ceramide species in mammals. In contrast, phytosphingosine (PHS and DHS are the main sphingoid bases in fungi. PHS and phytoceramide exist in particular tissues such as the epidermis in mammals, and involvement of ceramide species in PPARβ activation in cultured keratinocytes has been reported. The purpose of the present study is to investigate whether natural sphingolipids with C18 fatty acid and yeast-derived sphingoid bases activate PPARs as PPAR agonists. Method Lipids of brewer's yeast contain PHS- and DHS-based sphingolipids. To obtain the sphingoid bases, lipids were extracted from brewer's yeast and acid-hydrolyzed. The sphingoid base fraction was purified and quantified. To assess the effects of sphingolipids on PPAR activation, luciferase reporter assay was carried out. NIH/3T3 and human hepatoma (HepG2 cells were transfected with expression vectors for PPARs and retinoid × receptors, and PPAR responsive element reporter vector. When indicated, the PPAR/Gal4 chimera system was performed to enhance the credibility of experiments. Sphingolipids were added to the cells and the dual luciferase reporter assay was performed to determine the transcriptional activity of PPARs. Results We observed that phytoceramide increased the transcriptional activities of PPARs significantly, whereas ceramide and dihydroceramide did not change PPAR activities. Phytoceramide also increased transactivation of

  14. The Arabidopsis thaliana lectin receptor kinase LecRK-I.9 is required for full resistance to Pseudomonas syringae and affects jasmonate signalling

    NARCIS (Netherlands)

    Balagué, Claudine; Gouget, Anne; Bouchez, Olivier; Souriac, Camille; Haget, Nathalie; Boutet-Mercey, Stéphanie; Govers, Francine; Roby, Dominique; Canut, Hervé

    2016-01-01

    On microbial attack, plants can detect invaders and activate plant innate immunity. For the detection of pathogen molecules or cell wall damage, plants employ receptors that trigger the activation of defence responses. Cell surface proteins that belong to large families of lectin receptor kinases

  15. Conditional expression of constitutively active estrogen receptor {alpha} in chondrocytes impairs longitudinal bone growth in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Kazuhiro [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Tsukui, Tohru [Experimental Animal Laboratory, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Imazawa, Yukiko; Horie-Inoue, Kuniko [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Inoue, Satoshi, E-mail: INOUE-GER@h.u-tokyo.ac.jp [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer Conditional transgenic mice expressing constitutively active estrogen receptor {alpha} (caER{alpha}) in chondrocytes were developed. Black-Right-Pointing-Pointer Expression of caER{alpha} in chondrocytes impaired longitudinal bone growth in mice. Black-Right-Pointing-Pointer caER{alpha} affects chondrocyte proliferation and differentiation. Black-Right-Pointing-Pointer This mouse model is useful for understanding the physiological role of ER{alpha}in vivo. -- Abstract: Estrogen plays important roles in the regulation of chondrocyte proliferation and differentiation, which are essential steps for longitudinal bone growth; however, the mechanisms of estrogen action on chondrocytes have not been fully elucidated. In the present study, we generated conditional transgenic mice, designated as caER{alpha}{sup ColII}, expressing constitutively active mutant estrogen receptor (ER) {alpha} in chondrocytes, using the chondrocyte-specific type II collagen promoter-driven Cre transgenic mice. caER{alpha}{sup ColII} mice showed retardation in longitudinal growth, with short bone lengths. BrdU labeling showed reduced proliferation of hypertrophic chondrocytes in the proliferating layer of the growth plate of tibia in caER{alpha}{sup ColII} mice. In situ hybridization analysis of type X collagen revealed that the maturation of hypertrophic chondrocytes was impaired in caER{alpha}{sup ColII} mice. These results suggest that ER{alpha} is a critical regulator of chondrocyte proliferation and maturation during skeletal development, mediating longitudinal bone growth in vivo.

  16. Peroxisome Proliferator-Activated Receptor Targets for the Treatment of Metabolic Diseases

    Directory of Open Access Journals (Sweden)

    Francisco A. Monsalve

    2013-01-01

    Full Text Available Metabolic syndrome is estimated to affect more than one in five adults, and its prevalence is growing in the adult and pediatric populations. The most widely recognized metabolic risk factors are atherogenic dyslipidemia, elevated blood pressure, and elevated plasma glucose. Individuals with these characteristics commonly manifest a prothrombotic state and a proinflammatory state as well. Peroxisome proliferator-activated receptors (PPARs may serve as potential therapeutic targets for treating the metabolic syndrome and its related risk factors. The PPARs are transcriptional factors belonging to the ligand-activated nuclear receptor superfamily. So far, three isoforms of PPARs have been identified, namely, PPAR-α, PPAR-β/δ, and PPAR-γ. Various endogenous and exogenous ligands of PPARs have been identified. PPAR-α and PPAR-γ are mainly involved in regulating lipid metabolism, insulin sensitivity, and glucose homeostasis, and their agonists are used in the treatment of hyperlipidemia and T2DM. Whereas PPAR-β/δ function is to regulate lipid metabolism, glucose homeostasis, anti-inflammation, and fatty acid oxidation and its agonists are used in the treatment of metabolic syndrome and cardiovascular diseases. This review mainly focuses on the biological role of PPARs in gene regulation and metabolic diseases, with particular focus on the therapeutic potential of PPAR modulators in the treatment of thrombosis.

  17. Five layers of receptor signalling in γδ T cell differentiation and activation

    Directory of Open Access Journals (Sweden)

    Sérgio T. Ribeiro

    2015-01-01

    Full Text Available The contributions of gamma-delta T cells to immunity to infection or tumours critically depend on their activation and differentiation into effectors capable of secreting cytokines and killing infected or transformed cells. These processes are molecularly controlled by surface receptors that capture key extracellular cues and convey downstream intracellular signals that regulate gamma-delta T cell physiology. The understanding of how environmental signals are integrated by gamma-delta T cells is critical for their manipulation in clinical settings. Here we discuss how different classes of surface receptors impact on human and murine gamma-delta T cell differentiation, activation and expansion. In particular, we review the role of five receptor types: the T cell receptor (TCR, costimulatory receptors, cytokine receptors, NK receptors and inhibitory receptors. Some of the key players are the costimulatory receptors CD27 and CD28, which differentially impact on pro-inflammatory subsets of gamma-delta T cells; the cytokine receptors IL-2R, IL-7R and IL-15R, which drive functional differentiation and expansion of gamma-delta T cells; the NK receptor NKG2D and its contribution to gamma-delta T cell cytotoxicity; and the inhibitory receptors PD-1 and BTLA that control gamma-delta T cell homeostasis. We discuss these and other receptors in the context of a five-step model of receptor signalling in gamma-delta T cell differentiation and activation, and discuss its implications for the manipulation of gamma-delta T cells in immunotherapy.

  18. Chemokine-like receptor 1 deficiency does not affect the development of insulin resistance and nonalcoholic fatty liver disease in mice.

    Directory of Open Access Journals (Sweden)

    Nanda Gruben

    Full Text Available The adipokine chemerin and its receptor, chemokine-like receptor 1 (Cmklr1, are associated with insulin resistance and nonalcoholic fatty liver disease (NAFLD, which covers a broad spectrum of liver diseases, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH. It is possible that chemerin and/or Cmklr1 exert their effects on these disorders through inflammation, but so far the data have been controversial. To gain further insight into this matter, we studied the effect of whole-body Cmklr1 deficiency on insulin resistance and NAFLD. In view of the primary role of macrophages in hepatic inflammation, we also transplanted bone marrow from Cmklr1 knock-out (Cmklr1-/- mice and wild type (WT mice into low-density lipoprotein receptor knock-out (Ldlr-/- mice, a mouse model for NASH. All mice were fed a high fat, high cholesterol diet containing 21% fat from milk butter and 0.2% cholesterol for 12 weeks. Insulin resistance was assessed by an oral glucose tolerance test, an insulin tolerance test, and by measurement of plasma glucose and insulin levels. Liver pathology was determined by measuring hepatic inflammation, fibrosis, lipid accumulation and the NAFLD activity score (NAS. Whole-body Cmklr1 deficiency did not affect body weight gain or food intake. In addition, we observed no differences between WT and Cmklr1-/- mice for hepatic inflammatory and fibrotic gene expression, immune cell infiltration, lipid accumulation or NAS. In line with this, we detected no differences in insulin resistance. In concordance with whole-body Cmklr1 deficiency, the absence of Cmklr1 in bone marrow-derived cells in Ldlr-/- mice did not affect their insulin resistance or liver pathology. Our results indicate that Cmklr1 is not involved in the pathogenesis of insulin resistance or NAFLD. Thus, we recommend that the associations reported between Cmklr1 and insulin resistance or NAFLD should be interpreted with caution.

  19. Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep

    Directory of Open Access Journals (Sweden)

    Shoulong Deng

    2016-01-01

    Full Text Available Toll-like receptor 4 (TLR4 is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS. Consequently, production of malondialdehyde (MDA was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px, was increased. Real-time PCR showed that expression of activating protein-1 (AP-1 and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1 and catalase (CAT were reduced. In transgenic sheep, glutathione (GSH levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation of γ-glutamylcysteine synthetase (γ-GCS was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promoted γ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis.

  20. Troglitazone inhibits cell proliferation by attenuation of epidermal growth factor receptor signaling independent of peroxisome proliferator-activated receptor γ

    Institute of Scientific and Technical Information of China (English)

    Xiaoqi Li; Xuanming Yang; Youli Xu; Xuejun Jiang; Xin Li; Fajun Nan; Hong Tang

    2009-01-01

    Peroxisome proliferator-activated receptors (PPAR) belong to the nuclear hormone receptor superfamily of ligand-dependent transcription factors. Recent results have shown that agonists of PPARy, such as troglitazone (TGZ), can inhibit cell proliferation and promote cell differentiation independent of PPARγ. In the present study, we provide evidence that TGZ may bind directly to EGFR and trigger its signaling and internalization independent of PPARγ. Detailed studies revealed that prolonged incubation with TGZ effectively attenuated EGFR signaling by target-ing the receptor to the endo-lysosomal degradation machinery. Although the extracellular signal-regulated kinase-signaling pathway was transiently activated by TGZ in EGFR overexpressing cancer cells, inhibition of EGF-induced Akt phosphorylation most likely accounted for the growth arrest of tumor cells caused by TGZ at pharmacologically achievable concentrations. Therefore, we have provided a new line of evidence indicating that TGZ inhibits cell pro-liferation by promoting EGFR degradation and attenuating Akt phosphorylation.

  1. Selective glucocorticoid receptor-activating adjuvant therapy in cancer treatments

    Science.gov (United States)

    Sundahl, Nora; Clarisse, Dorien; Bracke, Marc; Offner, Fritz; Berghe, Wim Vanden; Beck, Ilse M.

    2016-01-01

    Although adverse effects and glucocorticoid resistance cripple their chronic use, glucocorticoids form the mainstay therapy for acute and chronic inflammatory disorders, and play an important role in treatment protocols of both lymphoid malignancies and as adjuvant to stimulate therapy tolerability in various solid tumors. Glucocorticoid binding to their designate glucocorticoid receptor (GR), sets off a plethora of cell-specific events including therapeutically desirable effects, such as cell death, as well as undesirable effects, including chemotherapy resistance, systemic side effects and glucocorticoid resistance. In this context, selective GR agonists and modulators (SEGRAMs) with a more restricted GR activity profile have been developed, holding promise for further clinical development in anti-inflammatory and potentially in cancer therapies. Thus far, the research into the prospective benefits of selective GR modulators in cancer therapy limped behind. Our review discusses how selective GR agonists and modulators could improve the therapy regimens for lymphoid malignancies, prostate or breast cancer. We summarize our current knowledge and look forward to where the field should move to in the future. Altogether, our review clarifies novel therapeutic perspectives in cancer modulation via selective GR targeting.

  2. Activation of mesolimbic dopaminergic neurons following central administration of histamine is mediated by H1 receptors.

    Science.gov (United States)

    Fleckenstein, A E; Lookingland, K J; Moore, K E

    1993-01-01

    The effect of intracerebroventricular administration of histamine on the activity of mesolimbic and nigrostriatal dopaminergic (DA) neurons was determined in male rats. The activity of these neurons was estimated by measuring: (1) the accumulation of 3,4-dihydroxyphenylalanine (DOPA) after administration of a decarboxylase inhibitor, and (2) the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens and striatum, which contain the terminals of these neurons. Central administration of histamine increased both DOPA accumulation and DOPAC concentrations in the nucleus accumbens, but was without effect in the striatum. The increase in DOPAC concentrations in the nucleus accumbens occurred within 10 min and was sustained for at least 120 min. The H1 antagonist mepyramine blocked whereas the H2 antagonist zolantidine did not affect histamine-induced increases in DOPAC concentrations in the nucleus accumbens. Neither mepyramine nor zolantidine affected basal DOPAC concentrations in the nucleus accumbens. These results indicate that central administration of histamine stimulates mesolimbic DA neurons through an action at the H1 receptor, but has no effect upon the activity of nigrostriatal DA neurons.

  3. Does lunisolar gravitational tide affect the activity of animals?

    Science.gov (United States)

    Deshcherevskii, A. V.; Sidorin, A. Ya.

    2010-12-01

    Multiyear time series obtained by the continuous instrumental monitoring of the electrical activity (EA) of weakly electric fish Gnathonemus leopoldianus and the motor activity (MA) of the freshwater catfish Hoplosternum thoracatum and the cockroach Blaberus craniifer are compared to the parameters of the lunisolar gravitational tide. These curves are observed to be very similar for a large number of time intervals. However, a more detailed analysis shows this to be only a superficial resemblance caused by the closeness of the periods of diurnal and semidiurnal rhythms of bioindicator activity (the dominant rhythms in EA and MA patterns) and the periods of main gravitational tidal waves. It is concluded that the lunisolar gravitational tide has no significant effect on animal behavior in our experiment.

  4. A cholinergic receptor gene (CHRM2) affects event-related oscillations.

    Science.gov (United States)

    Jones, Kevin A; Porjesz, Bernice; Almasy, Laura; Bierut, Laura; Dick, Danielle; Goate, Alison; Hinrichs, Anthony; Rice, John P; Wang, Jen C; Bauer, Lance O; Crowe, Raymond; Foroud, Tatiana; Hesselbrock, Victor; Kuperman, Samuel; Nurnberger, John; O'Connor, Sean J; Rohrbaugh, John; Schuckit, Marc A; Tischfield, Jay; Edenberg, Howard J; Begleiter, Henri

    2006-09-01

    We report genetic linkage and association findings which implicate the gene encoding the muscarinic acetylcholine receptor M2 (CHRM2) in the modulation of a scalp-recorded electrophysiological phenotype. The P3 (P300) response was evoked using a three-stimulus visual oddball paradigm and a phenotype that relates to the energy in the theta band (4-5 Hz) was analyzed. Studies have shown that similar electrophysiological measures represent cognitive correlates of attention, working memory, and response selection; a role has been suggested for the ascending cholinergic pathway in the same functions. The results of our genetic association tests, combined with knowledge regarding the presence of presynaptic cholinergic M2 autoreceptors in the basal forebrain, indicate that the cognitive processes required by the experiment may in part be mediated by inhibitory neural networks. These findings underscore the utility of electrophysiology and neurogenetics in the understanding of cognitive function and the study of brain-related disorders.

  5. Factors affecting estrogen receptor status in a multiracial Asian country: an analysis of 3557 cases.

    Science.gov (United States)

    Yip, C H; Pathy, N Bhoo; Uiterwaal, C S; Taib, N A; Tan, G H; Mun, K S; Choo, W Y; Rhodes, A

    2011-04-01

    Estrogen receptor (ER) positive rates in breast cancer may be influenced by grade, stage, age and race. This study reviews the ER positive rates over a 15-year period at the University Malaya Medical Centre, Kuala Lumpur, Malaysia. Data on ER status of 3557 patients from 1994 to 2008 was analyzed. ER status was determined by immunohistochemistry with a cut-off point of 10%. ER positivity increased by about 2% for every 5-year cohort, from 54.5% in 1994-1998 to 58.4% in 2004-2008. Ethnicity and grade were significantly associated with ER positivity rates: Malay women were found to have a higher risk of ER negative tumors compared with Chinese women. Grade 1 cancers were nine times more likely to be ER positive compared with grade 3 cancers. In summary, the proportion of ER positive cancers increased with each time period, and ethnicity and grade were independent factors that influenced ER positive rates.

  6. Effect of niflumic acid on electromechanical coupling by tachykinin NK1 receptor activation in rabbit colon.

    Science.gov (United States)

    Patacchini, R; Santicioli, P; Maggi, C A

    1996-05-15

    We have investigated the effect of the Cl- channel blocker, niflumic acid, on the contractile response and electromechanical coupling activated by stimulation of the tachykinin NK1 receptor in the longitudinal muscle of rabbit proximal colon, in the presence of indomethacin (5 microM). The application of submaximal equieffective concentrations of the tachykinin NK1 receptor-selective agonist [Sar9]substance P sulfone (30 nM), of carbachol (300 nM) and KCl (40 mM), produced distinct phasic and tonic components of contraction. Niflumic acid (10-100 microM) preferentially and markedly inhibited the tonic component of the response to [Sar9]substance P sulfone and to carbachol, without affecting the response to KCl. Nifedipine (1 microM) abolished the response to KCl and greatly reduced the response to [Sar9]substance P sulfone and carbachol. The nifedipine-resistant response to [Sar9]substance P sulfone was attenuated by niflumic acid (100 microM), while that to carbachol was unaffected. In sucrose gap experiments, superfusion with niflumic acid (100 microM), in the presence of nifedipine (3 microM), produced membrane hyperpolarization, which was totally blocked by tetraethylammonium (10 mM). Niflumic acid inhibited both depolarization and contraction induced by [Sar9]substance P sulfone, both in the absence or in the presence of tetraethylammonium. The present findings support the idea that a niflumic acid-sensitive mechanism, probably an effect on Cl- channels, takes part in the post-receptorial events activated by tachykinin NK1 receptor stimulation in the longitudinal muscle of rabbit colon, and suggest that this mechanism would be more important for generating the sustained tonic than the phasic component of contraction.

  7. Micellar lipid composition affects micelle interaction with class B scavenger receptor extracellular loops.

    Science.gov (United States)

    Goncalves, Aurélie; Gontero, Brigitte; Nowicki, Marion; Margier, Marielle; Masset, Gabriel; Amiot, Marie-Josèphe; Reboul, Emmanuelle

    2015-06-01

    Scavenger receptors (SRs) like cluster determinant 36 (CD36) and SR class B type I (SR-BI) play a debated role in lipid transport across the intestinal brush border membrane. We used surface plasmon resonance to analyze real-time interactions between the extracellular protein loops and various ligands ranging from single lipid molecules to mixed micelles. Micelles mimicking physiological structures were necessary for optimal binding to both the extracellular loop of CD36 (lCD36) and the extracellular loop of SR-BI (lSR-BI). Cholesterol, phospholipid, and fatty acid micellar content significantly modulated micelle binding to and dissociation from the transporters. In particular, high phospholipid micellar concentrations inhibited micelle binding to both receptors (-53.8 and -74.4% binding at 0.32 mM compared with 0.04 mM for lCD36 and lSR-BI, respectively, P < 0.05). The presence of fatty acids was crucial for micelle interactions with both proteins (94.4 and 81.3% binding with oleic acid for lCD36 and lSR-BI, respectively, P < 0.05) and fatty acid type substitution within the micelles was the component that most impacted micelle binding to the transporters. These effects were partly due to subsequent modifications in micellar size and surface electric charge, and could be correlated to micellar vitamin D uptake by Caco-2 cells. Our findings show for the first time that micellar lipid composition and micellar properties are key factors governing micelle interactions with SRs.

  8. Toll Like Receptor 4 Affects the Cerebral Biochemical Changes Induced by MPTP Treatment.

    Science.gov (United States)

    Conte, Carmela; Roscini, Luca; Sardella, Roccaldo; Mariucci, Giuseppina; Scorzoni, Stefania; Beccari, Tommaso; Corte, Laura

    2017-01-21

    The etiology and pathogenesis of Parkinson's disease (PD) are still unclear. However, multiple lines of evidence suggest a critical role of the toll like receptor 4 (TLR4) in inflammatory response and neuronal death. Neuroinflammation may be associated with the misfolding and aggregation of proteins accompanied by a change in their secondary structure. Recent findings also suggest that biochemical perturbations in cerebral lipid content could contribute to the pathogenesis of central nervous system (CNS) disorders, including PD. Thus, it is of great importance to determine the biochemical changes that occur in PD. In this respect, Fourier Transform Infrared (FTIR) spectroscopy represents a useful tool to detect molecular alterations in biological systems in response to stress stimuli. By relying upon FTIR approach, this study was designed to elucidate the potential role of TLR4 in biochemical changes induced by methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin in a mouse model of PD. The analysis of the FTIR spectra was performed in different brain regions of both wild type (WT) and toll like receptor 4-deficient (TLR4(-/-)) mice. It revealed that each brain region exhibited a characteristic molecular fingerprint at baseline, with no significant differences between genotypes. Conversely, WT and TLR4(-/-) mice showed differential biochemical response to MPTP toxicity, principally related to lipid and protein composition. These differences appeared to be characteristic for each brain area. Furthermore, the present study showed that WT mice resulted more vulnerable than TLR4(-/-) animals to striatal dopamine (DA) depletion following MPTP treatment. These results support the hypothesis of a possible involvement of TLR4 in biochemical changes occurring in neurodegeneration.

  9. Ambient temperature affects the temperature threshold for TRPM8 activation through interaction of phosphatidylinositol 4,5-bisphosphate.

    Science.gov (United States)

    Fujita, Fumitaka; Uchida, Kunitoshi; Takaishi, Masayuki; Sokabe, Takaaki; Tominaga, Makoto

    2013-04-03

    Cold sensation is an important and fundamental sense for animals and it is known to be affected by ambient temperature. Transient Receptor Potential Melastatin 8 (TRPM8), a nonselective cation channel expressed in a subset of peripheral afferent fibers, acts as a cold sensor, having an activation threshold of ∼28°C. Although the cold temperature threshold of TRPM8 is affected by menthol or pH, ambient temperature has not been reported to affect it. Because the cold temperature threshold was thought to be unchanged by alterations in ambient temperature, the relativity of temperature sensing in different ambient temperatures could not be understood at the level of molecular function of thermosensitive TRP channels. Here, we show that ambient temperature changed the temperature threshold for activation of human and rat TRPM8 in a heterologous expression system and cold responses in mouse DRG neurons. Moreover, reducing the level of cellular phosphatidylinositol 4,5-bisphosphate (PIP2) attenuated changes in the cold temperature threshold after alterations in ambient temperature. A single amino acid mutation at position 1008 in the C terminus of TRPM8 (arginine to glutamine) also attenuated changes in the cold temperature threshold induced by ambient temperature. These findings suggest that ambient temperature does affect the temperature threshold for TRPM8 activation through interaction of PIP2.

  10. Is receptor oligomerization causally linked to activation of the EGF receptor kinase?

    Science.gov (United States)

    Rintoul, D. A.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    Transduction of a signal from an extracellular peptide hormone to produce an intracellular response is often mediated by a cell surface receptor, which is usually a glycoprotein. The secondary intracellular signal(s) generated after hormone binding to the receptor have been intensively studied. The nature of the primary signal generated by ligand binding to the receptor is understood less well in most cases. The particular case of the epidermal growth factor (EGF) receptor is analyzed, and evidence for or against two dissimilar models of primary signal transduction is reviewed. Evidence for the most widely accepted current model is found to be unconvincing. Evidence for the other model is substantial but indirect; a direct test of this model remains to be done.

  11. Sulindac metabolites inhibit epidermal growth factor receptor activation and expression

    Directory of Open Access Journals (Sweden)

    Pangburn Heather A

    2005-09-01

    Full Text Available Abstract Background Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs is associated with a decreased mortality from colorectal cancer (CRC. NSAIDs induce apoptotic cell death in colon cancer cells in vitro and inhibit growth of neoplastic colonic mucosa in vivo however, the biochemical mechanisms required for these growth inhibitory effects are not well defined. We previously reported that metabolites of the NSAID sulindac downregulate extracellular-signal regulated kinase 1/2 (ERK1/2 signaling and that this effect is both necessary and sufficient for the apoptotic effects of these drugs. The goal of this project was to specifically test the hypothesis that sulindac metabolites block activation and/or expression of the epidermal growth factor (EGF receptor (EGFR. Methods HT29 human colon cancer cells were treated with EGF, alone, or in the presence of sulindac sulfide or sulindac sulfone. Cells lysates were assayed by immunoblotting for phosphorylated EGFR (pEGFR, pY1068, total EGFR, phosphorylated ERK1/2 (pERK1/2, total ERK1/2, activated caspase-3, and α-tubulin. Results EGF treatment rapidly induced phosphorylation of both EGFR and ERK1/2 in HT29 colon cancer cells. Pretreatment with sulindac metabolites for 24 h blocked EGF-induced phosphorylation of both EGFR and ERK1/2 and decreased total EGFR protein expression. Under basal conditions, downregulation of pEGFR and total EGFR was detected as early as 12 h following sulindac sulfide treatment and persisted through at least 48 h. Sulindac sulfone induced downregulation of pEGFR and total EGFR was detected as early as 1 h and 24 h, respectively, following drug treatment, and persisted through at least 72 h. EGFR downregulation by sulindac metabolites was observed in three different CRC cell lines, occurred prior to the observed downregulation of pERK1/2 and induction of apoptosis by these drugs, and was not dependent of caspase activation. Conclusion These results suggest that

  12. Neural activities during affective processing in people with Alzheimer's disease

    NARCIS (Netherlands)

    Lee, Tatia M. C.; Sun, Delin; Leung, Mei-Kei; Chu, Leung-Wing; Keysers, Christian

    2013-01-01

    This study examined brain activities in people with Alzheimer's disease when viewing happy, sad, and fearful facial expressions of others. A functional magnetic resonance imaging and a voxel-based morphometry methodology together with a passive viewing of emotional faces paradigm were employed to co

  13. Toward understanding how the lactone moiety of discodermolide affects activity.

    Science.gov (United States)

    Shaw, Simon J; Sundermann, Kurt F; Burlingame, Mark A; Myles, David C; Freeze, B Scott; Xian, Ming; Brouard, Ignacio; Smith, Amos B

    2005-05-11

    A series of simplified discodermolide analogues have been designed and synthesized in an attempt to understand the role of the lactone ring. These synthetic efforts have led to an unsubstituted butyrolactone 9 being generated, which shows improved activity over the natural product.

  14. 5-HT1A receptors modulate small-conductance Ca2+-activated K+ channels

    DEFF Research Database (Denmark)

    Grunnet, Morten; Jespersen, Thomas; Perrier, Jean-François

    2004-01-01

    Small-conductance calcium-activated potassium channels (SK) are responsible for the medium afterhyperpolarisation (mAHP) following action potentials in neurons. Here we tested the ability of serotonin (5-HT) to modulate the activity of SK channels by coexpressing 5-HT1A receptors with different...... subtypes of SK channels (SK1, SK2, and SK3) in Xenopus laevis oocytes. SK channels were activated by intracellular injection of Cd2+. Subsequent activation of 5-HT1A receptors by 8-OH-DPAT always produced an inhibition of the SK current, showing the existence of a specific pathway between the receptor...

  15. Pharmacological activation of 5-HT7 receptors reduces nerve injury-induced mechanical and thermal hypersensitivity.

    Science.gov (United States)

    Brenchat, Alex; Nadal, Xavier; Romero, Luz; Ovalle, Sergio; Muro, Asunción; Sánchez-Arroyos, Ricard; Portillo-Salido, Enrique; Pujol, Marta; Montero, Ana; Codony, Xavier; Burgueño, Javier; Zamanillo, Daniel; Hamon, Michel; Maldonado, Rafael; Vela, José Miguel

    2010-06-01

    The involvement of the 5-HT(7) receptor in nociception and pain, particularly chronic pain (i.e., neuropathic pain), has been poorly investigated. In the present study, we examined whether the 5-HT(7) receptor participates in some modulatory control of nerve injury-evoked mechanical hypersensitivity and thermal (heat) hyperalgesia in mice. Activation of 5-HT(7) receptors by systemic administration of the selective 5-HT(7) receptor agonist AS-19 (1 and 10mg/kg) exerted a clear-cut reduction of mechanical and thermal hypersensitivities that were reversed by co-administering the selective 5-HT(7) receptor antagonist SB-258719. Interestingly, blocking of 5-HT(7) receptors with SB-258719 (2.5 and 10mg/kg) enhanced mechanical (but not thermal) hypersensitivity in nerve-injured mice and induced mechanical hypersensitivity in sham-operated mice. Effectiveness of the treatment with a 5-HT(7) receptor agonist was maintained after repeated systemic administration: no tolerance to the antiallodynic and antihyperalgesic effects was developed following treatment with the selective 5-HT(7) receptor agonist E-57431 (10mg/kg) twice daily for 11 days. The 5-HT(7) receptor co-localized with GABAergic cells in the dorsal horn of the spinal cord, suggesting that the activation of spinal inhibitory GABAergic interneurons could contribute to the analgesic effects of 5-HT(7) receptor agonists. In addition, a significant increase of 5-HT(7) receptors was found by immunohistochemistry in the ipsilateral dorsal horn of the spinal cord after nerve injury, suggesting a "pain"-triggered regulation of receptor expression. These results support the idea that the 5-HT(7) receptor subtype is involved in the control of pain and point to a new potential use of 5-HT(7) receptor agonists for the treatment of neuropathic pain.

  16. GABA/sub B/ receptor activation inhibits Ca/sup 2 +/-activated potassium channels in synaptosomes: involvement of G-proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ticku, M.K.; Delgado, A.

    1989-01-01

    /sup 86/Rb-efflux assay from preloaded synaptosomes of rat cerebral cortex was developed to study the effect of GABA/sub B/ receptor agonist baclofen on Ca/sup 2 +/-activated K/sup +/-channels. Depolarization of /sup 86/Rb-loaded synaptosomes in physiological buffer increased Ca/sup 2 +/-activated /sup 86/Rb-efflux by 400%. The /sup 86/Rb-efflux was blocked by quinine sulfate, tetraethylammonium, and La/sup 3 +/ indicating the involvement of Ca/sup 2 +/-activated K/sup +/-channels. (-)Baclofen inhibited Ca/sup 2 +/-activated /sup 86/Rb-efflux in a stereospecific manner. The inhibitory effect of (-)baclofen was mediated by GABA/sub B/ receptor activation, since it was blocked by GABA/sub B/ antagonist phaclofen, but not by bicuculline. Further, pertussis toxin also blocked the ability of baclofen or depolarizing action to affect Ca/sup 2 +/-activated K/sup +/-channels. These results suggest that baclofen inhibits Ca/sup 2 +/-activated K/sup +/-channels in synaptosomes and these channels are regulated by G-proteins. This assay may provide an ideal in vitro model to study GABA/sub B/ receptor pharmacology.

  17. Estrogen receptor β exerts tumor repressive functions in human malignant pleural mesothelioma via EGFR inactivation and affects response to gefitinib.

    Directory of Open Access Journals (Sweden)

    Giulia Pinton

    Full Text Available BACKGROUND: The role of estrogen and estrogen receptors in oncogenesis has been investigated in various malignancies. Recently our group identified estrogen receptor beta (ERβ expression as an independent prognostic factor in the progression of human Malignant Pleural Mesothelioma (MMe, but the underlying mechanism by which ERβ expression in tumors determines clinical outcome remains largely unknown. This study is aimed at investigating the molecular mechanisms of ERβ action in MMe cells and disclosing the potential translational implications of these results. METHODS: We modulated ERβ expression in REN and MSTO-211H MMe cell lines and evaluated cell proliferation and EGF receptor (EGFR activation. RESULTS: Our data indicate that ERβ knockdown in ER positive cells confers a more invasive phenotype, increases anchorage independent proliferation and elevates the constitutive activation of EGFR-coupled signal transduction pathways. Conversely, re-expression of ERβ in ER negative cells confers a more epithelioid phenotype, decreases their capacity for anchorage independent growth and down-modulates proliferative signal transduction pathways. We identify a physical interaction between ERβ, EGFR and caveolin 1 that results in an altered internalization and in a selective reduced activation of EGFR-coupled signaling, when ERβ is over-expressed. We also demonstrate that differential expression of ERβ influences MMe tumor cell responsiveness to the therapeutic agent: Gefitinib. CONCLUSIONS: This study describes a role for ERβ in the modulation of cell proliferation and EGFR activation and provides a rationale to facilitate the targeting of a subgroup of MMe patients who would benefit most from therapy with Gefitinib alone or in combination with Akt inhibitors.

  18. Comparative study on transcriptional activity of 17 parabens mediated by estrogen receptor α and β and androgen receptor.

    Science.gov (United States)

    Watanabe, Yoko; Kojima, Hiroyuki; Takeuchi, Shinji; Uramaru, Naoto; Ohta, Shigeru; Kitamura, Shigeyuki

    2013-07-01

    The structure-activity relationships of parabens which are widely used as preservatives for transcriptional activities mediated by human estrogen receptor α (hERα), hERβ and androgen receptor (hAR) were investigated. Fourteen of 17 parabens exhibited hERα and/or hERβ agonistic activity at concentrations of ≤ 1 × 10(-5)M, whereas none of the 17 parabens showed AR agonistic or antagonistic activity. Among 12 parabens with linear alkyl chains ranging in length from C₁ to C₁₂, heptylparaben (C₇) and pentylparaben (C₅) showed the most potent ERα and ERβ agonistic activity in the order of 10(-7)M and 10(-8)M, respectively, and the activities decreased in a stepwise manner as the alkyl chain was shortened to C₁ or lengthened to C₁₂. Most parabens showing estrogenic activity exhibited ERβ-agonistic activity at lower concentrations than those inducing ERα-agonistic activity. The estrogenic activity of butylparaben was markedly decreased by incubation with rat liver microsomes, and the decrease of activity was blocked by a carboxylesterase inhibitor. These results indicate that parabens are selective agonists for ERβ over ERα; their interactions with ERα/β are dependent on the size and bulkiness of the alkyl groups; and they are metabolized by carboxylesterases, leading to attenuation of their estrogenic activity.

  19. Quantitative impedimetric NPY-receptor activation monitoring and signal pathway profiling in living cells.

    Science.gov (United States)

    te Kamp, Verena; Lindner, Ricco; Jahnke, Heinz-Georg; Krinke, Dana; Kostelnik, Katja B; Beck-Sickinger, Annette G; Robitzki, Andrea A

    2015-05-15

    Label-free and non-invasive monitoring of receptor activation and identification of the involved signal pathways in living cells is an ongoing analytic challenge and a great opportunity for biosensoric systems. In this context, we developed an impedance spectroscopy-based system for the activation monitoring of NPY-receptors in living cells. Using an optimized interdigital electrode array for sensitive detection of cellular alterations, we were able for the first time to quantitatively detect the NPY-receptor activation directly without a secondary or enhancer reaction like cAMP-stimulation by forskolin. More strikingly, we could show that the impedimetric based NPY-receptor activation monitoring is not restricted to the Y1-receptor but also possible for the Y2- and Y5-receptor. Furthermore, we could monitor the NPY-receptor activation in different cell lines that natively express NPY-receptors and proof the specificity of the observed impedimetric effect by agonist/antagonist studies in recombinant NPY-receptor expressing cell lines. To clarify the nature of the observed impedimetric effect we performed an equivalent circuit analysis as well as analyzed the role of cell morphology and receptor internalization. Finally, an antagonist based extensive molecular signal pathway analysis revealed small alterations of the actin cytoskeleton as well as the inhibition of at least L-type calcium channels as major reasons for the observed NPY-induced impedance increase. Taken together, our novel impedance spectroscopy based NPY-receptor activation monitoring system offers the opportunity to identify signal pathways as well as for novel versatile agonist/antagonist screening systems for identification of novel therapeutics in the field of obesity and cancer.

  20. Method and tool for prognosticating HIV infection in a subject by measuring soluble urokinase plasminogen activator receptor, degradation products thereof, and urokinase plasminogen activator receptor

    DEFF Research Database (Denmark)

    2000-01-01

    Method of diagnosing and/or prognosticating HIV infection in a subject comprising the steps of: (a) performing in vitro a measurement of the level of a marker in the form of (i) urokinase plasminogen activator receptor (uPAR), (ii) soluble urokinase plasminogen activator receptor (suPAR), (iii......) urokinase-type plasminogen activator (uPA), (iv) one or more degradation products of (i), (ii), or (iii), and/or (v) an mRNA for (i), (ii) or (iii), in a biological fluid sample from a subject, and (b) using the measurement value obtained to evaluate the state of the subject....

  1. Masculine sexual activity affects slow wave sleep in Golden hamsters.

    Science.gov (United States)

    Jiménez-Anguiano, A; Arteaga-Silva, M; Velázquez-Moctezuma, J

    2003-02-15

    The sleep pattern is modified by events occurring during wakefulness. In rats, it has been shown that male sexual behavior has a direct influence on sleeping patterns, increasing slow wave sleep (SWS) duration. On the other hand, the sexual behavior pattern of the male Golden hamster differs from the copulatory pattern of male rats. Male hamsters copulate faster and they do not display the motor inhibition observed in rats after each ejaculation. Moreover, close to exhaustion, hamsters display a behavioral pattern known as Long Intromission, which has been linked to an sexual inhibitory process. The present study was performed to determine the effects of male sexual activity on the sleep pattern in hamsters. Subjects were allowed to copulate for 30 and 60 min. In addition, the effect of locomotor activity was also assessed. The results show that male sexual behavior induced a significant increase of SWS II, with a reduction of wakefulness. No effect was observed on REM sleep. Locomotor activity produced only a slight effect on sleep. The results are discussed in terms of the similarities between the effects observed after sexual behavior on sleep in rats and hamsters, despite the substantial differences in the behavioral pattern.

  2. Disturbances of electrodynamic activity affect abortion in human

    Science.gov (United States)

    Jandová, A.; Nedbalová, M.; Kobilková, J.; Čoček, A.; Dohnalová, A.; Cifra, M.; Pokorný, J.

    2011-12-01

    Biochemical research of biological systems is highly developed, and it has disclosed a spectrum of chemical reactions, genetic processes, and the pathological development of various diseases. The fundamental hypothesis of physical processes in biological systems, in particular of coherent electrically polar vibrations and electromagnetic activity, was formulated by H. Fröhlich he assumed connection of cancer process with degradation of coherent electromagnetic activity. But the questions of cellular structures capable of the coherent electrical polar oscillation, mechanisms of energy supply, and the specific role of the endogenous electromagnetic fields in transport, organisation, interactions, and information transfer remained open. The nature of physical disturbances caused by some diseases (including the recurrent abortion in humans and the cancer) was unknown. We have studied the reasons of recurrent abortions in humans by means of the cell mediated immunity (using immunologic active RNA prepared from blood of inbred laboratory mice strain C3H/H2K, infected with the lactate dehydrogenase elevating virus-LD V) and the cytogenetic examination from karyotype pictures. The recurrent abortion group contained women with dg. spontaneous abortion (n = 24) and the control group was composed of 30 healthy pregnant women. Our hypothesis was related to quality of endometrium in relation to nidation of the blastocyst. The energetic insufficiency (ATP) inhibits normal development of fetus and placenta. We hope that these ideas might have impact on further research, which could provide background for effective interdisciplinary cooperation of malignant and non-malignant diseases.

  3. Defective insulin secretion by chronic glucagon receptor activation in glucose intolerant mice.

    Science.gov (United States)

    Ahlkvist, Linda; Omar, Bilal; Valeur, Anders; Fosgerau, Keld; Ahrén, Bo

    2016-03-01

    Stimulation of insulin secretion by short-term glucagon receptor (GCGR) activation is well characterized; however, the effect of long-term GCGR activation on β-cell function is not known, but of interest, since hyperglucagonemia occurs early during development of type 2 diabetes. Therefore, we examined whether chronic GCGR activation affects insulin secretion in glucose intolerant mice. To induce chronic GCGR activation, high-fat diet fed mice were continuously (2 weeks) infused with the stable glucagon analog ZP-GA-1 and challenged with oral glucose and intravenous glucose±glucagon-like peptide 1 (GLP1). Islets were isolated to evaluate the insulin secretory response to glucose±GLP1 and their pancreas were collected for immunohistochemical analysis. Two weeks of ZP-GA-1 infusion reduced insulin secretion both after oral and intravenous glucose challenges in vivo and in isolated islets. These inhibitory effects were corrected for by GLP1. Also, we observed increased β-cell area and islet size. We conclude that induction of chronic ZP-GA-1 levels in glucose intolerant mice markedly reduces insulin secretion, and thus, we suggest that chronic activation of the GCGR may contribute to the failure of β-cell function during development of type 2 diabetes.

  4. Novel indole and azaindole (pyrrolopyridine) cannabinoid (CB) receptor agonists: design, synthesis, structure-activity relationships, physicochemical properties and biological activity

    NARCIS (Netherlands)

    Blaazer, A.R.; Lange, J.H.M.; van der Neut, M.A.W.; Mulder, A.; den Boon, F.S.; Werkman, T.R.; Kruse, C.G.; Wadman, W.J.

    2011-01-01

    The discovery, synthesis and structure-activity relationship (SAR) of a novel series of cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptor ligands are reported. Based on the aminoalkylindole class of cannabinoid receptor agonists, a biphenyl moiety was introduced as novel lipophilic indole 3-acyl

  5. Src Family Kinases and Receptors: Analysis of Three Activation Mechanisms by Dynamic Systems Modeling

    OpenAIRE

    Fuß, Hendrik; Dubitzky, Werner; Downes, C. Stephen; Kurth, Mary Jo

    2007-01-01

    Src family kinases (SFKs) interact with a number of cellular receptors. They participate in diverse signaling pathways and cellular functions. Most of the receptors involved in SFK signaling are characterized by similar modes of regulation. This computational study discusses a general kinetic model of SFK-receptor interaction. The analysis of the model reveals three major ways of SFK activation: release of inhibition by C-terminal Src kinase, weakening of the inhibitory intramolecular phospho...

  6. Mechanisms involved in VPAC receptors activation and regulation: lessons from pharmacological and mutagenesis studies.

    Directory of Open Access Journals (Sweden)

    Ingrid eLanger

    2012-10-01

    Full Text Available VIP plays diverse and important role in human physiology and physiopathology and their receptors constitute potential targets for the treatment of several diseases such as neurodegenerative disorder, asthma, diabetes and inflammatory diseases. This article reviews the current knowledge regarding the two VIP receptors, VPAC1 and VPAC2, with respect to mechanisms involved in receptor activation, G protein coupling, signaling, regulation and oligomerization.

  7. Activity of protease-activated receptors in primary cultured human myenteric neurons

    Directory of Open Access Journals (Sweden)

    Eva Maria Kugler

    2012-09-01

    Full Text Available Activity of the four known protease-activated receptors (PARs has been well studied in rodent enteric nervous system and results in animal models established an important role for neuronal PAR2. We recently demonstrated that, unlike in rodents, PAR1 is the dominant neuronal protease receptor in the human submucous plexus. With this study we investigated whether this also applies to the human myenteric plexus. We used voltage sensitive dye recordings to detect action potential discharge in primary cultures of human myenteric neurons in response to PAR activating peptides (AP. Application of the PAR1-AP (TFLLR or PAR4-AP (GYPGQV evoked spike discharge in 79% or 23% of myenteric neurons, respectively. The PAR1-AP response was mimicked by the endogenous PAR1 activator thrombin and blocked by the PAR1 antagonists SCH79797. Human myenteric neurons did not respond to PAR2-AP. This was not due to culture conditions because all three PAR-APs evoked action potentials in cultured guinea pig myenteric neurons. Consecutive application of PAR-APs revealed coexpression (relative to the population responding to PAR-APs of PAR1/PAR2 in 51%, PAR1/PAR4 in 43% and of PAR2/PAR4 in 29% of guinea pig myenteric neurons. Our study provided further evidence for the prominent role of neuronal PAR1 in the human enteric nervous system.

  8. Adenosine A3 receptor activation is neuroprotective against retinal neurodegeneration.

    Science.gov (United States)

    Galvao, Joana; Elvas, Filipe; Martins, Tiago; Cordeiro, M Francesca; Ambrósio, António Francisco; Santiago, Ana Raquel

    2015-11-01

    Death of retinal neural cells, namely retinal ganglion cells (RGCs), is a characteristic of several retinal neurodegenerative diseases. Although the role of adenosine A3 receptor (A3R) in neuroprotection is controversial, A3R activation has been reported to afford protection against several brain insults, with few studies in the retina. In vitro models (retinal neural and organotypic cultures) and animal models [ischemia-reperfusion (I-R) and partial optic nerve transection (pONT)] were used to study the neuroprotective properties of A3R activation against retinal neurodegeneration. The A3R selective agonist (2-Cl-IB-MECA, 1 μM) prevented apoptosis (TUNEL(+)-cells) induced by kainate and cyclothiazide (KA + CTZ) in retinal neural cultures (86.5 ± 7.4 and 37.2 ± 6.1 TUNEL(+)-cells/field, in KA + CTZ and KA + CTZ + 2-Cl-IB-MECA, respectively). In retinal organotypic cultures, 2-Cl-IB-MECA attenuated NMDA-induced cell death, assessed by TUNEL (17.3 ± 2.3 and 8.3 ± 1.2 TUNEL(+)-cells/mm(2) in NMDA and NMDA+2-Cl-IB-MECA, respectively) and PI incorporation (ratio DIV4/DIV2 3.3 ± 0.3 and 1.3 ± 0.1 in NMDA and NMDA+2-Cl-IB-MECA, respectively) assays. Intravitreal 2-Cl-IB-MECA administration afforded protection against I-R injury decreasing the number of TUNEL(+) cells by 72%, and increased RGC survival by 57%. Also, intravitreal administration of 2-Cl-IB-MECA inhibited apoptosis (from 449.4 ± 37.8 to 207.6 ± 48.9 annexin-V(+)-cells) and RGC loss (from 1.2 ± 0.6 to 8.1 ± 1.7 cells/mm) induced by pONT. This study demonstrates that 2-Cl-IB-MECA is neuroprotective to the retina, both in vitro and in vivo. Activation of A3R may have great potential in the management of retinal neurodegenerative diseases characterized by RGC death, as glaucoma and diabetic retinopathy, and ischemic diseases.

  9. Pharmacology and toxicology of fibrates as hypolipidemic drugs mediated by nuclear receptor peroxisome proliferator—activated receptor

    Institute of Scientific and Technical Information of China (English)

    SugaT

    2002-01-01

    PPAR(peroxisome proliferator-activated receptor) is a family of nuclear receptor.In recent years,it has been focused for the discovery and development of new drugs which are mediated by PPARs.Fibrate hypolipidemic drugs are the specific and potent ligands to PPAR alpha and have been widely used for the treatment of hyperlipidemia.But these drugs induce hepatocarcinogenesis in rodent animals after the long-term administration.However,there are species differences on these phenomena which are not seen in mammals ioncluding human.To clarify the mechanism of carcinogenesis by these drugs in important for the evaluation of safety of these drugs in human.

  10. Central Insulin Action Activates Kupffer Cells by Suppressing Hepatic Vagal Activation via the Nicotinic Alpha 7 Acetylcholine Receptor

    Directory of Open Access Journals (Sweden)

    Kumi Kimura

    2016-03-01

    Full Text Available Central insulin action activates hepatic IL-6/STAT3 signaling, which suppresses the gene expression of hepatic gluconeogenic enzymes. The vagus nerve plays an important role in this centrally mediated hepatic response; however, the precise mechanism underlying this brain-liver interaction is unclear. Here, we present our findings that the vagus nerve suppresses hepatic IL-6/STAT3 signaling via α7-nicotinic acetylcholine receptors (α7-nAchR on Kupffer cells, and that central insulin action activates hepatic IL-6/STAT3 signaling by suppressing vagal activity. Indeed, central insulin-mediated hepatic IL-6/STAT3 activation and gluconeogenic gene suppression were impeded in mice with hepatic vagotomy, pharmacological cholinergic blockade, or α7-nAchR deficiency. In high-fat diet-induced obese and insulin-resistant mice, control of the vagus nerve by central insulin action was disturbed, inducing a persistent increase of inflammatory cytokines. These findings suggest that dysregulation of the α7-nAchR-mediated control of Kupffer cells by central insulin action may affect the pathogenesis of chronic hepatic inflammation in obesity.

  11. Xenobiotic-induced hepatocyte proliferation associated with constitutive active/androstane receptor (CAR or peroxisome proliferator-activated receptor α (PPARα is enhanced by pregnane X receptor (PXR activation in mice.

    Directory of Open Access Journals (Sweden)

    Ryota Shizu

    Full Text Available Xenobiotic-responsive nuclear receptors pregnane X receptor (PXR, constitutive active/androstane receptor (CAR and peroxisome proliferator-activated receptor α (PPARα play pivotal roles in the metabolic functions of the liver such as xenobiotics detoxification and energy metabolism. While CAR or PPARα activation induces hepatocyte proliferation and hepatocarcinogenesis in rodent models, it remains unclear whether PXR activation also shows such effects. In the present study, we have investigated the role of PXR in the xenobiotic-induced hepatocyte proliferation with or without CAR activation by 1,4-bis[2-(3,5-dichloropyridyloxy]benzene (TCPOBOP and phenobarbital, or PPARα activation by Wy-14643 in mice. Treatment with TCPOBOP or phenobarbital increased the percentage of Ki-67-positive nuclei as well as mRNA levels of cell proliferation-related genes in livers as expected. On the other hand, treatment with the PXR activator pregnenolone 16α-carbonitrile (PCN alone showed no such effects. Surprisingly, PCN co-treatment significantly augmented the hepatocyte proliferation induced by CAR activation with TCPOBOP or phenobarbital in wild-type mice but not in PXR-deficient mice. Intriguingly, PXR activation also augmented the hepatocyte proliferation induced by Wy-14643 treatment. Moreover, PCN treatment increased the RNA content of hepatocytes, suggesting the induction of G0/G1 transition, and reduced mRNA levels of Cdkn1b and Rbl2, encoding suppressors of cell cycle initiation. Our present findings indicate that xenobiotic-induced hepatocyte proliferation mediated by CAR or PPARα is enhanced by PXR co-activation despite that PXR activation alone does not cause the cell proliferation in mouse livers. Thus PXR may play a novel and unique role in the hepatocyte/liver hyperplasia upon exposure to xenobiotics.

  12. High vitamin D3 diet administered during active colitis negatively affects bone metabolism in an adoptive T cell transfer model.

    Science.gov (United States)

    Larmonier, C B; McFadden, R-M T; Hill, F M; Schreiner, R; Ramalingam, R; Besselsen, D G; Ghishan, F K; Kiela, P R

    2013-07-01

    Decreased bone mineral density (BMD) represents an extraintestinal complication of inflammatory bowel disease (IBD). Vitamin D₃ has been considered a viable adjunctive therapy in IBD. However, vitamin D₃ plays a pleiotropic role in bone modeling and regulates the bone formation-resorption balance, depending on the physiological environment, and supplementation during active IBD may have unintended consequences. We evaluated the effects of vitamin D₃ supplementation during the active phase of disease on colonic inflammation, BMD, and bone metabolism in an adoptive IL-10-/- CD4⁺ T cell transfer model of chronic colitis. High-dose vitamin D₃ supplementation for 12 days during established disease had negligible effects on mucosal inflammation. Plasma vitamin D₃ metabolites correlated with diet, but not disease, status. Colitis significantly reduced BMD. High-dose vitamin D₃ supplementation did not affect cortical bone but led to a further deterioration of trabecular bone morphology. In mice fed a high vitamin D₃ diet, colitis more severely impacted bone formation markers (osteocalcin and bone alkaline phosphatase) and increased bone resorption markers, ratio of receptor activator of NF-κB ligand to osteoprotegrin transcript, plasma osteoprotegrin level, and the osteoclast activation marker tartrate-resistant acid phosphatase (ACp5). Bone vitamin D receptor expression was increased in mice with chronic colitis, especially in the high vitamin D₃ group. Our data suggest that vitamin D₃, at a dose that does not improve inflammation, has no beneficial effects on bone metabolism and density during active colitis or may adversely affect BMD and bone turnover. These observations should be taken into consideration in the planning of further clinical studies with high-dose vitamin D₃ supplementation in patients with active IBD.

  13. PPG neurons of the lower brain stem and their role in brain GLP-1 receptor activation.

    Science.gov (United States)

    Trapp, Stefan; Cork, Simon C

    2015-10-15

    Within the brain, glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Additionally, GLP-1 influences the mesolimbic reward system to modulate the rewarding properties of palatable food. GLP-1 is produced in the gut and by hindbrain preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarii (NTS) and medullary intermediate reticular nucleus. Transgenic mice expressing glucagon promoter-driven yellow fluorescent protein revealed that PPG neurons not only project to central autonomic control regions and mesolimbic reward centers, but also strongly innervate spinal autonomic neurons. Therefore, these brain stem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to sympathetic preganglionic neurons. Electrical recordings from PPG neurons in vitro have revealed that they receive synaptic inputs from vagal afferents entering via the solitary tract. Vagal afferents convey satiation to the brain from signals like postprandial gastric distention or activation of peripheral GLP-1 receptors. CCK and leptin, short- and long-term satiety peptides, respectively, increased the electrical activity of PPG neurons, while ghrelin, an orexigenic peptide, had no effect. These findings indicate that satiation is a main driver of PPG neuronal activation. They also show that PPG neurons are in a prime position to respond to both immediate and long-term indicators of energy and feeding status, enabling regulation of both energy balance and general autonomic homeostasis. This review discusses the question of whether PPG neurons, rather than gut-derived GLP-1, are providing the physiological substrate for the effects elicited by central nervous system GLP-1 receptor activation.

  14. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells.

    Science.gov (United States)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes.

  15. Killer immunoglobulin-like receptor (KIR and HLA genotypes affect the outcome of allogeneic kidney transplantation.

    Directory of Open Access Journals (Sweden)

    Izabela Nowak

    Full Text Available BACKGROUND: Recipient NK cells may detect the lack of recipient's (i.e., self HLA antigens on donor renal tissue by means of their killer cell immunoglobulin-like receptors (KIRs. KIR genes are differently distributed in individuals, possibly contributing to differences in response to allogeneic graft. METHODOLOGY/PRINCIPAL FINDINGS: We compared frequencies of 10 KIR genes by PCR-SSP in 93 kidney graft recipients rejecting allogeneic renal transplants with those in 190 recipients accepting grafts and 690 healthy control individuals. HLA matching results were drawn from medical records. We observed associations of both a full-length KIR2DS4 gene and its variant with 22-bp deletion with kidney graft rejection. This effect was modulated by the HLA-B,-DR matching, particularly in recipients who did not have glomerulonephritis but had both forms of KIR2DS4 gene. In contrast, in recipients with glomerulonephritis, HLA compatibility seemed to be much less important for graft rejection than the presence of KIR2DS4 gene. Simultaneous presence of both KIR2DS4 variants strongly increased the probability of rejection. Interestingly, KIR2DS5 seemed to protect the graft in the presence of KIR2DS4fl but in the absence of KIR2DS4del. CONCLUSIONS/SIGNIFICANCE: Our results suggest a protective role of KIR2DS5 in graft rejection and an association of KIR2DS4 with kidney rejection, particularly in recipients with glomerulonephritis.

  16. Genetic variation of the serotonin 2a receptor affects hippocampal novelty processing in humans.

    Directory of Open Access Journals (Sweden)

    Björn H Schott

    Full Text Available Serotonin (5-hydroxytryptamine, 5-HT is an important neuromodulator in learning and memory processes. A functional genetic polymorphism of the 5-HT 2a receptor (5-HTR2a His452Tyr, which leads to blunted intracellular signaling, has previously been associated with explicit memory performance in several independent cohorts, but the underlying neural mechanisms are thus far unclear. The human hippocampus plays a critical role in memory, particularly in the detection and encoding of novel information. Here we investigated the relationship of 5-HTR2a His452Tyr and hippocampal novelty processing in 41 young, healthy subjects using functional magnetic resonance imaging (fMRI. Participants performed a novelty/familiarity task with complex scene stimuli, which was followed by a delayed recognition memory test 24 hours later. Compared to His homozygotes, Tyr carriers exhibited a diminished hippocampal response to novel stimuli and a higher tendency to judge novel stimuli as familiar during delayed recognition. Across the cohort, the false alarm rate during delayed recognition correlated negatively with the hippocampal novelty response. Our results suggest that previously reported effects of 5-HTR2a on explicit memory performance may, at least in part, be mediated by alterations of hippocampal novelty processing.

  17. Genetic variation of the serotonin 2a receptor affects hippocampal novelty processing in humans.

    Science.gov (United States)

    Schott, Björn H; Seidenbecher, Constanze I; Richter, Sylvia; Wüstenberg, Torsten; Debska-Vielhaber, Grazyna; Schubert, Heike; Heinze, Hans-Jochen; Richardson-Klavehn, Alan; Düzel, Emrah

    2011-01-18

    Serotonin (5-hydroxytryptamine, 5-HT) is an important neuromodulator in learning and memory processes. A functional genetic polymorphism of the 5-HT 2a receptor (5-HTR2a His452Tyr), which leads to blunted intracellular signaling, has previously been associated with explicit memory performance in several independent cohorts, but the underlying neural mechanisms are thus far unclear. The human hippocampus plays a critical role in memory, particularly in the detection and encoding of novel information. Here we investigated the relationship of 5-HTR2a His452Tyr and hippocampal novelty processing in 41 young, healthy subjects using functional magnetic resonance imaging (fMRI). Participants performed a novelty/familiarity task with complex scene stimuli, which was followed by a delayed recognition memory test 24 hours later. Compared to His homozygotes, Tyr carriers exhibited a diminished hippocampal response to novel stimuli and a higher tendency to judge novel stimuli as familiar during delayed recognition. Across the cohort, the false alarm rate during delayed recognition correlated negatively with the hippocampal novelty response. Our results suggest that previously reported effects of 5-HTR2a on explicit memory performance may, at least in part, be mediated by alterations of hippocampal novelty processing.

  18. GH deficiency status combined with GH receptor polymorphism affects response to GH in children.

    Science.gov (United States)

    Valsesia, Armand; Chatelain, Pierre; Stevens, Adam; Peterkova, Valentina A; Belgorosky, Alicia; Maghnie, Mohamad; Antoniazzi, Franco; Koledova, Ekaterina; Wojcik, Jerome; Farmer, Pierre; Destenaves, Benoit; Clayton, Peter

    2015-12-01

    Meta-analysis has shown a modest improvement in first-year growth response to recombinant human GH (r-hGH) for carriers of the exon 3-deleted GH receptor (GHRd3) polymorphism but with significant interstudy variability. The associations between GHRd3 and growth response to r-hGH over 3 years in relation to severity of GH deficiency (GHD) were investigated in patients from 14 countries. Treatment-naïve pre-pubertal children with GHD were enrolled from the PREDICT studies (NCT00256126 and NCT00699855), categorized by peak GH level (peak GH) during provocation test: ≤4 μg/l (severe GHD; n=45) and >4 to GH level. GH peak level (higher vs lower) and GHRd3 (fl/fl vs d3 carriers) combined status was associated with height change over 3 years (PGH had lower growth than subjects with fl/fl (median difference after 3 years -3.3 cm; -0.3 SDS). Conversely, GHRd3 carriers with higher peak GH had better growth (+2.7 cm; +0.2 SDS). Similar patterns were observed for GH-dependent biomarkers. GE profiles were significantly different between the groups, indicating that the interaction between GH status and GHRd3 carriage can be identified at a transcriptomic level. This study demonstrates that responses to r-hGH depend on the interaction between GHD severity and GHRd3 carriage.

  19. Aging affects B-cell antigen receptor repertoire diversity in primary and secondary lymphoid tissues.

    Science.gov (United States)

    Tabibian-Keissar, Hilla; Hazanov, Lena; Schiby, Ginette; Rosenthal, Noemie; Rakovsky, Aviya; Michaeli, Miri; Shahaf, Gitit Lavy; Pickman, Yishai; Rosenblatt, Kinneret; Melamed, Doron; Dunn-Walters, Deborah; Mehr, Ramit; Barshack, Iris

    2016-02-01

    The elderly immune system is characterized by reduced responses to infections and vaccines, and an increase in the incidence of autoimmune diseases and cancer. Age-related deficits in the immune system may be caused by peripheral homeostatic pressures that limit bone marrow B-cell production or migration to the peripheral lymphoid tissues. Studies of peripheral blood B-cell receptor spectratypes have shown that those of the elderly are characterized by reduced diversity, which is correlated with poor health status. In the present study, we performed for the first time high-throughput sequencing of immunoglobulin genes from archived biopsy samples of primary and secondary lymphoid tissues in old (74 ± 7 years old, range 61-89) versus young (24 ± 5 years old, range 18-45) individuals, analyzed repertoire diversities and compared these to results in peripheral blood. We found reduced repertoire diversity in peripheral blood and lymph node repertoires from old people, while in the old spleen samples the diversity was larger than in the young. There were no differences in somatic hypermutation characteristics between age groups. These results support the hypothesis that age-related immune frailty stems from altered B-cell homeostasis leading to narrower memory B-cell repertoires, rather than changes in somatic hypermutation mechanisms.

  20. Profiling gene expression induced by protease-activated receptor 2 (PAR2 activation in human kidney cells.

    Directory of Open Access Journals (Sweden)

    Jacky Y Suen

    Full Text Available Protease-Activated Receptor-2 (PAR2 has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD and key events in tumor progression (angiogenesis, metastasis, but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293, a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2 and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2. Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes, the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2 and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15. Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4 known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents.

  1. Disturbances of electrodynamic activity affect abortion in animals

    Science.gov (United States)

    Nedbalova, M.; Jandova, A.; Dohnalova, A.

    2011-12-01

    A specific kind of intracellular organelles, the mitochondria, is the place of metabolic energy production by oxidative mechanism. We used cell mediated immunity method for verification of the energy metabolism (ATP production). The antigen (immunological functional RNA) was obtained from blood of inbred laboratory mice strain C3H/H2K, infected with the lactate dehydrogenase elevating virus (LDV) and prepared by the high pressure gel chromatography (HPGC). We have studied the immunological adaptability of LDH viral antigen in 62 pigs (12 parents and 50 piglings). Exitus of piglings was in case of positive imunological response on LDV. The statement results from a comparison of the relative frequency of an incidence of identical findings in male piglets and sows and from identical findings in female piglets and pigs. The efficient elaboration and utilization of energy in cell may be damaged by the changes of energy production systems and also by long-term parasitary depletion of ATP energy. Biological activity is based not only on biochemical but also on biophysical mechanisms. Biophysical processes are also involved in the transfer of information and its processing for making decisions and providing control, which are important parts of biological activity. These experimental results were used for the same study in human.

  2. Cellular phosphatases facilitate combinatorial processing of receptor-activated signals

    Directory of Open Access Journals (Sweden)

    Siddiqui Zaved

    2008-09-01

    Full Text Available Abstract Background Although reciprocal regulation of protein phosphorylation represents a key aspect of signal transduction, a larger perspective on how these various interactions integrate to contribute towards signal processing is presently unclear. For example, a key unanswered question is that of how phosphatase-mediated regulation of phosphorylation at the individual nodes of the signaling network translates into modulation of the net signal output and, thereby, the cellular phenotypic response. Results To address the above question we, in the present study, examined the dynamics of signaling from the B cell antigen receptor (BCR under conditions where individual cellular phosphatases were selectively depleted by siRNA. Results from such experiments revealed a highly enmeshed structure for the signaling network where each signaling node was linked to multiple phosphatases on the one hand, and each phosphatase to several nodes on the other. This resulted in a configuration where individual signaling intermediates could be influenced by a spectrum of regulatory phosphatases, but with the composition of the spectrum differing from one intermediate to another. Consequently, each node differentially experienced perturbations in phosphatase activity, yielding a unique fingerprint of nodal signals characteristic to that perturbation. This heterogeneity in nodal experiences, to a given perturbation, led to combinatorial manipulation of the corresponding signaling axes for the downstream transcription factors. Conclusion Our cumulative results reveal that it is the tight integration of phosphatases into the signaling network that provides the plasticity by which perturbation-specific information can be transmitted in the form of a multivariate output to the downstream transcription factor network. This output in turn specifies a context-defined response, when translated into the resulting gene expression profile.

  3. The formyl peptide receptor like-1 and scavenger receptor MARCO are involved in glial cell activation in bacterial meningitis

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    Jansen Sandra

    2011-02-01

    Full Text Available Abstract Background Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure mediates activation of the immune response in bacterial infection of the central nervous system (CNS. The chemotactic G-protein-coupled receptor (GPCR formyl-peptide-receptor like-1 (FPRL1 plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD. Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. Methods Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP and Neisseria meningitides (NM. Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2 phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene expression and signal transduction were determined. Results We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between

  4. Identification of chemical modulators of the constitutive activated receptor (CAR) in a gene expression compendium

    OpenAIRE

    Oshida, Keiyu; Vasani, Naresh; Jones, Carlton; Moore, Tanya; Hester, Susan; Nesnow, Stephen; Auerbach, Scott; Geter, David R.; Aleksunes, Lauren M; Thomas, Russell S.; Applegate, Dawn; Klaassen, Curtis D.; Corton, J. Christopher

    2015-01-01

    The nuclear receptor family member constitutive activated receptor (CAR) is activated by structurally diverse drugs and environmentally-relevant chemicals leading to transcriptional regulation of genes involved in xenobiotic metabolism and transport. Chronic activation of CAR increases liver cancer incidence in rodents, whereas suppression of CAR can lead to steatosis and insulin insensitivity. Here, analytical methods were developed to screen for chemical treatments in a gene expression comp...

  5. The protease-activated receptor-2 agonist induces gastric mucus secretion and mucosal cytoprotection

    OpenAIRE

    Kawabata, Atsufumi; Kinoshita, Mitsuhiro; Nishikawa, Hiroyuki; Kuroda, Ryotaro; Nishida, Minoru; Araki, Hiromasa; Arizono, Naoki; Oda, Yasuo; Kakehi, Kazuaki

    2001-01-01

    Protease-activated receptor-2 (PAR-2), a receptor activated by trypsin/tryptase, modulates smooth muscle tone and exocrine secretion in the salivary glands and pancreas. Given that PAR-2 is expressed throughout the gastrointestinal tract, we investigated effects of PAR-2 agonists on mucus secretion and gastric mucosal injury in the rat. PAR-2–activating peptides triggered secretion of mucus in the stomach, but not in the duodenum. This mucus secretion was abolished by pretreatment with capsai...

  6. Analysis of the epidermal growth factor receptor specific transcriptome: effect of receptor expression level and an activating mutation

    DEFF Research Database (Denmark)

    Pedersen, Mikkel W; Pedersen, Nina; Damstrup, Lars;

    2005-01-01

    moderately expressed or overexpressed at an in-itself transforming level. These changes were compared to those induced by the naturally occurring constitutively active variant EGFRvIII. This study provides novel insight on the activities and mechanisms of EGFRvIII and EGFR mediated transformation, as genes...... by interferons. Expression of this module was absent in the EGFRvIII-expressing cell line and the parental cell line. Treatment with the specific EGFR inhibitor AG1478 indicated that the regulations were primary, receptor-mediated events. Furthermore, activation of this module correlated with activation of STAT1...

  7. Tumor-Suppressive Activity of Lunatic Fringe in Prostate through Differential Modulation of Notch Receptor Activation

    Directory of Open Access Journals (Sweden)

    Shubing Zhang

    2014-02-01

    Full Text Available Elevated Notch ligand and receptor expression has been associated with aggressive forms of prostate cancer, suggesting a role for Notch signaling in regulation of prostate tumor initiation and progression. Here, we report a critical role for Lunatic Fringe (Lfng, which encodes an O-fucosylpeptide 3-ß-N-acetylglucosaminyltransferase known to modify epidermal growth factor repeats of Notch receptor proteins, in regulation of prostate epithelial differentiation and proliferation, as well as in prostate tumor suppression. Deletion of Lfng in mice caused altered Notch activation in the prostate, associated with elevated accumulation of Notch1, Notch2, and Notch4 intracellular domains, decreased levels of the putative Notch3 intracellular fragment, as well as increased expression of Hes1, Hes5, and Hey2. Loss of Lfng resulted in expansion of the basal layer, increased proliferation of both luminal and basal cells, and ultimately, prostatic intraepithelial neoplasia. The Lfng-null prostate showed down-regulation of prostatic tumor suppressor gene NKX3.1 and increased androgen receptor expression. Interestingly, expression of LFNG and NKX3.1 were positively correlated in publically available human prostate cancer data sets. Knockdown of LFNG in DU-145 prostate cancer cells led to expansion of CD44+CD24− and CD49f+CD24− stem/progenitor-like cell population associated with enhanced prostatosphere-forming capacity. Taken together, these data revealed a tumor-suppressive role for Lfng in the prostate through differential regulation of Notch signaling.

  8. An angiotensin II type 1 receptor activation switch patch revealed through evolutionary trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong;

    2010-01-01

    in the cytoplasmic parts of TM2, TM3, and TM6 to form an activation switch that is common to all family A 7TM receptors. We tested this hypothesis in the rat Angiotensin II (Ang II) type 1a (AT1a) receptor. The receptor has important roles in the cardiovascular system, but has also frequently been applied as a model...... for 7TM receptor activation and signaling. Six mutations: F66A, L67R, L70R, L119R, D125A, and I245F were targeted to the putative switch and assayed for changes in activation state by their ligand binding, signaling, and trafficking properties. All but one receptor mutant (that was not expressed well...

  9. Activities of calcitonin gene-related peptide (CGRP) and related peptides at the CGRP receptor

    Energy Technology Data Exchange (ETDEWEB)

    Maton, P.N.; Pradhan, T.; Zhou, Z.C.; Gardner, J.D.; Jensen, R.T. (National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, MD (USA))

    1990-05-01

    In guinea pig pancreatic acini rat calcitonin gene-related peptide (CGRP) increased amylase release 2-fold, salmon calcitonin had an efficacy of only 44% of that of CGRP and (Tyr0)CGRP(28-37) and human calcitonin had no actions. (Tyr0)CGRP(28-37), but not human calcitonin, antagonized the actions of CGRP in pancreatic acini with an IC50 of 3 microM. (Tyr0)CGRP(28-37) produced a parallel rightward shift in the dose-response curve for CGRP-stimulated amylase secretion. The inhibition was specific for CGRP and was reversible. Studies with 125I-CGRP demonstrated that CGRP, salmon calcitonin and (Tyr0)CGRP, but not human calcitonin, interacted with CGRP receptors on pancreatic acini. These results indicate that various CGRP-related peptides demonstrate different relationships between their abilities to occupy the CGRP receptor and to affect biologic activity, with CGRP itself being a full agonist, salmon calcitonin a partial agonist, (Tyr0)CGRP(28-37) a competitive antagonist, and human calcitonin having no actions.

  10. A2A adenosine receptor antagonism enhances synaptic and motor effects of cocaine via CB1 cannabinoid receptor activation.

    Directory of Open Access Journals (Sweden)

    Alessandro Tozzi

    Full Text Available BACKGROUND: Cocaine increases the level of endogenous dopamine (DA in the striatum by blocking the DA transporter. Endogenous DA modulates glutamatergic inputs to striatal neurons and this modulation influences motor activity. Since D2 DA and A2A-adenosine receptors (A2A-Rs have antagonistic effects on striatal neurons, drugs targeting adenosine receptors such as caffeine-like compounds, could enhance psychomotor stimulant effects of cocaine. In this study, we analyzed the electrophysiological effects of cocaine and A2A-Rs antagonists in striatal slices and the motor effects produced by this pharmacological modulation in rodents. PRINCIPAL FINDINGS: Concomitant administration of cocaine and A2A-Rs antagonists reduced glutamatergic synaptic transmission in striatal spiny neurons while these drugs failed to produce this effect when given in isolation. This inhibitory effect was dependent on the activation of D2-like receptors and the release of endocannabinoids since it was prevented by L-sulpiride and reduced by a CB1 receptor antagonist. Combined application of cocaine and A2A-R antagonists also reduced the firing frequency of striatal cholinergic interneurons suggesting that changes in cholinergic tone might contribute to this synaptic modulation. Finally, A2A-Rs antagonists, in the presence of a sub-threshold dose of cocaine, enhanced locomotion and, in line with the electrophysiological experiments, this enhanced activity required activation of D2-like and CB1 receptors. CONCLUSIONS: The present study provides a possible synaptic mechanism explaining how caffeine-like compounds could enhance psychomotor stimulant effects of cocaine.

  11. Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂ activity in rat skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Andrew Philp

    Full Text Available Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR coactivator-1α (PGC-1α and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4: control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]. Gastrocnemius (GTN muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E finished with higher AMPK-α2 activity (147%, p<0.05, nuclear AMPK-α2 and PGC-1α, but no difference in AMPK-α1 activity compared to CON. In addition, PPAR-∂ binding to the CPT1 promoter was significantly increased only in the LG-E group. Finally, cell reporter studies in contracting C2C12 myotubes indicated that PPAR-∂ activity following contraction is sensitive to glucose availability, providing mechanistic insight into the association between PPAR-∂ and glycogen content/substrate availability. The present study is the first to examine PPAR-∂ activity in skeletal muscle in response to an acute bout of endurance exercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal

  12. [INHIBITORS OF MAP-KINASE PATHWAY U0126 AND PD98059 DIFFERENTLY AFFECT ORGANIZATION OF TUBULIN CYTOSKELETON AFTER STIMULATION OF EGF RECEPTOR ENDOCYTOSIS].

    Science.gov (United States)

    Zlobina, M V; Steblyanko, Yu Yu; Shklyaeva, M A; Kharchenko, V V; Salova, A V; Kornilova, E S

    2015-01-01

    To confirm the hypothesis about the involvement of EGF-stimulated MAP-kinase ERK1/2 in the regulation of microtubule (MT) system, the influence of two widely used ERK1/2 inhibitors, U0126 and PD98059, on the organization of tubulin cytoskeleton in interphase HeLa cells during EGF receptor endocytosis has been investigated. We have found that addition of U0126 or PD98059 to not-stimulated with EGF ells for 30 min has no effect on radially organized MT system. However, in the case of U0126 addition before EGF endocytosis stimulation, the number of MT per cell decreased within 15 min after such stimulation and was followed by complete MT depolymerization by 60-90 min. Stimulation of EGF endocytosis in the presence of PD98059 resulted only in insignificant depolymerization of MT and it could be detected mainly from their minus-ends. At the same time, MT regions close to plasma membrane became stabilized, which was proved by increase in tubulin acetylation level. This situation was characteristic for all period of the experiment. It has been also found that the inhibitors affect endocytosis dynamics of EGF-receptor complexes. Quantitative analysis demonstrated that the stimulation of endocytosis in the presence of U0126 generated a greater number of endosomes compared to control cells, and their number did not change significantly during the experiment. All these endosomes were localized peripherally. Effect of PD98059 resulted in the formation of lower number of endosomes that in control, but they demonstrated very slow clusterization despite the presence of some intact MT. Both inhibitors decreased EGFR colocolization with early endosomal marker EEA1, which indicated a delay in endosome fusions and maturation. The inhibitors were also shown to affect differently phospho-ERK 1 and 2 forms: U0126 completely inhibited phospho-ERK1 and 2, white, in the presence of PD98059, the two ERK forms demonstrated sharp transient activation in 15 min after stimulation, but only

  13. Activation of histamine H3 receptors in human nasal mucosa inhibits sympathetic vasoconstriction.

    Science.gov (United States)

    Varty, LoriAnn M; Gustafson, Eric; Laverty, Maureen; Hey, John A

    2004-01-19

    The peripheral histamine H3 receptor is a presynaptic heterologous receptor located on postganglionic sympathetic nerve fibers innervating sympathetic effector systems such as blood vessels and the heart. An extensive body of evidence shows that activation of the histamine H3 receptor attenuates sympathetic tone by presynaptic inhibition of noradrenaline release. It is proposed that this sympathoinhibitory action, in vivo, leads to reduced vasoconstriction, thereby eliciting a vasodilatory effect. In humans, the peripheral histamine H3 receptor has also been shown to exert a sympathoinhibitory function on specific peripheral autonomic effector systems. For example, human saphenous vein and heart possess functional presynaptic histamine H3 receptors on the sympathetic nerve terminals that upon activation decrease the sympathetic tone to these respective organs. The present studies were conducted to define the role of histamine H3 receptors on neurogenic sympathetic vasoconstrictor responses in human nasal turbinate mucosa. Contractility studies were conducted to evaluate the effect of histamine H3 receptor activation on sympathetic vasoconstriction in surgically isolated human nasal turbinate mucosa. We found that the histamine H3 receptor agonist, (R)-alpha-methylhistamine (30 and 300 nM), inhibited electrical field stimulation-induced (neurogenic) sympathetic vasoconstriction in a concentration-dependent fashion. Pretreatment with the selective histamine H3 receptor antagonist, clobenpropit (100 nM), blocked the sympathoinhibitory effect of (R)-alpha-methylhistamine on the neurogenic sympathetic vasoconstriction. In addition, analysis of Taqman mRNA expression studies showed a specific, high level of distribution of the histamine H3 receptor localized in the human nasal mucosa. Taken together, these studies indicate that histamine H3 receptors modulate vascular contractile responses in human nasal mucosa most likely by inhibiting noradrenaline release from

  14. Activation of peroxisome proliferator-activated receptor alpha in rat spinal cord after peripheral noxious stimulation.

    Science.gov (United States)

    Benani, A; Heurtaux, T; Netter, P; Minn, A

    2004-10-07

    Following recurrent noxious stimulation, both functional modification and structural reorganization such as activation of the arachidonate cascade or axon sprouting occur in the central nervous system (CNS). It has been recently proposed that these alterations observed during chronic pain state were supported by an intensification of the lipid metabolism. In this regard, it has been shown that mRNA coding for several fatty acid metabolizing enzymes are up-regulated in the rat lumbar spinal cord in response to persistent nociception induced by a peripheral inflammation. As peroxisome proliferators-activated receptor (PPAR) could mediate such effects, we therefore investigated the activation of this transcription factor in the rat spinal cord following subcutaneous injection of complete Freund's adjuvant (CFA) into a hind paw. In this study, we compared the DNA-binding activity of nuclear proteins extracted from healthy and inflamed rats toward a PPAR response element. Using electrophoretic mobility-shift assay (EMSA), we found that only the PPARalpha isoform was activated in the rat spinal cord after CFA injection. This activation occurred rapidly, as early as 30 min post-CFA injection, and was persistent up to 10 h, reaching a maximum at 6h after CFA injection. In view of the consequences of PPARalpha activation in other tissues, these results suggest that fatty acid utilization is enhanced in the CNS during chronic pain state. Although the physiopathological relevance of PPARalpha activation during hyperalgesia needs further investigation, we provided here a new player in the molecular modeling of pain pathways.

  15. How Lipid Membranes Affect Pore Forming Toxin Activity.

    Science.gov (United States)

    Rojko, Nejc; Anderluh, Gregor

    2015-12-15

    , events associated with pore formation can modulate properties of the lipid membrane and affect its organization. Model membranes do not necessarily reproduce the physicochemical properties of the native cellular membrane, and caution is needed when transferring results from model to native lipid membranes. In this context, the utilization of novel approaches that enable studying PFTs on living cells at a single molecule level should reveal complex protein-lipid membrane interactions in greater detail.

  16. Different efficacy of adenosine and NECA derivatives at the human A3 adenosine receptor: insight into the receptor activation switch.

    Science.gov (United States)

    Dal Ben, Diego; Buccioni, Michela; Lambertucci, Catia; Kachler, Sonja; Falgner, Nico; Marucci, Gabriella; Thomas, Ajiroghene; Cristalli, Gloria; Volpini, Rosaria; Klotz, Karl-Norbert

    2014-01-15

    A3 Adenosine receptors are promising drug targets for a number of diseases and intense efforts are dedicated to develop selective agonists and antagonists of these receptors. A series of adenosine derivatives with 2-(ar)-alkynyl chains, with high affinity and different degrees of selectivity for human A3 adenosine receptors was tested for the ability to inhibit forskolin-stimulated adenylyl cyclase. All these derivatives are partial agonists at A3 adenosine receptors; their efficacy is not significantly modified by the introduction of small alkyl substituents in the N(6)-position. In contrast, the adenosine-5'-N-ethyluronamide (NECA) analogs of 2-(ar)-alkynyladenosine derivatives are full A3 agonists. Molecular modeling analyses were performed considering both the conformational behavior of the ligands and the impact of 2- and 5'-substituents on ligand-target interaction. The results suggest an explanation for the different agonistic behavior of adenosine and NECA derivatives, respectively. A sub-pocket of the binding site was analyzed as a crucial interaction domain for receptor activation.

  17. Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptors.

    Science.gov (United States)

    Ster, Jeanne; Mateos, José María; Grewe, Benjamin Friedrich; Coiret, Guyllaume; Corti, Corrado; Corsi, Mauro; Helmchen, Fritjof; Gerber, Urs

    2011-06-14

    Impaired function or expression of group II metabotropic glutamate receptors (mGluRIIs) is observed in brain disorders such as schizophrenia. This class of receptor is thought to modulate activity of neuronal circuits primarily by inhibiting neurotransmitter release. Here, we characterize a postsynaptic excitatory response mediated by somato-dendritic mGluRIIs in hippocampal CA3 pyramidal cells and in stratum oriens interneurons. The specific mGluRII agonists DCG-IV or LCCG-1 induced an inward current blocked by the mGluRII antagonist LY341495. Experiments with transgenic mice revealed a significant reduction of the inward current in mGluR3(-/-) but not in mGluR2(-/-) mice. The excitatory response was associated with periods of synchronized activity at theta frequency. Furthermore, cholinergically induced network oscillations exhibited decreased frequency when mGluRIIs were blocked. Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity.

  18. Kaempferol inhibits cancer cell growth by antagonizing estrogen-related receptor α and γ activities.

    Science.gov (United States)

    Wang, Haibin; Gao, Minghui; Wang, Junjian

    2013-11-01

    Kaempferol is a dietary flavonoid that can function as a selective estrogen receptor modulator (SERM). Estrogen-related receptors alpha and gamma (ERRα and ERRγ) are orphan nuclear receptors that play important roles in mitochondrial biogenesis and cancer development. We have shown that kaempferol can functionally antagonize the activities of ERRs based on both response element reporter systems and target gene analysis. Kaempferol modulation of mitochondrial function and suppression cancer cell growth has been confirmed. These findings suggest that kaempferol may exert their anti-cancer activities through antagonizing ERRs activities.

  19. A Molecular Mechanism for Sequential Activation of a G Protein-Coupled Receptor

    DEFF Research Database (Denmark)

    Grundmann, Manuel; Tikhonova, Irina G; Hudson, Brian D;

    2016-01-01

    Ligands targeting G protein-coupled receptors (GPCRs) are currently classified as either orthosteric, allosteric, or dualsteric/bitopic. Here, we introduce a new pharmacological concept for GPCR functional modulation: sequential receptor activation. A hallmark feature of this is a stepwise ligand...

  20. Analysis of Activated Platelet-Derived Growth Factor β Receptor and Ras-MAP Kinase Pathway in Equine Sarcoid Fibroblasts

    Directory of Open Access Journals (Sweden)

    Gennaro Altamura

    2013-01-01

    Full Text Available Equine sarcoids are skin tumours of fibroblastic origin affecting equids worldwide. Bovine papillomavirus type-1 (BPV-1 and, less commonly, type-2 are recognized as etiological factors of sarcoids. The transforming activity of BPV is related to the functions of its major oncoprotein E5 which binds to the platelet-derived growth factor β receptor (PDGFβR causing its phosphorylation and activation. In this study, we demonstrate, by coimmunoprecipitation and immunoblotting, that in equine sarcoid derived cell lines PDGFβR is phosphorylated and binds downstream molecules related to Ras-mitogen-activated protein kinase-ERK pathway thus resulting in Ras activation. Imatinib mesylate is a tyrosine kinase receptors inhibitor which selectively inhibits the activation of PDGFβR in the treatment of several human and animal cancers. Here we show that imatinib inhibits receptor phosphorylation, and cell viability assays demonstrate that this drug decreases sarcoid fibroblasts viability in a dose-dependent manner. This study contributes to a better understanding of the molecular mechanisms involved in the pathology of sarcoids and paves the way to a new therapeutic approach for the treatment of this common equine skin neoplasm.

  1. Melatonin-receptor-1-deficiency affects neurogenic differentiation factor immunoreaction in pancreatic islets and enteroendocrine cells of mice.

    Science.gov (United States)

    Shalabi, Andree; Fischer, Claudia; Korf, Horst-Werner; von Gall, Charlotte

    2013-09-01

    Neurogenic differentiation factor (NeuroD) is a transcription factor involved in the differentiation of neurons and in the control of energy balance and metabolism. It plays a key role in type 1 and type 2 diabetes. Melatonin is an important rhythmic endocrine signal within the circadian system of mammals and modulates insulin secretion and glucose metabolism. In the mouse pars tuberalis, NeuroD mRNA levels show day/night variation, which is independent of the molecular clock gene mPER1 but depends on the functional melatonin receptor 1 (MT1). So far, little is known about the effect of melatonin on NeuroD synthesis in the gastrointestinal tract. Thus, NeuroD protein levels and cellular localization were analyzed by immunohistochemistry in pancreatic islets and duodenal enteroendocrine cells of MT1- and mPER1-deficienct mice. In addition, the localization of NeuroD-positive cells was analyzed by double-immunofluorescence and confocal laser microscopy. In duodenal enteroendocrine cells and pancreatic islets of WT and PER1-deficient mice, NeuroD immunoreaction showed a peak during the early subjective night. In contrast, this peak was absent in MT1-deficent mice. These data suggest that melatonin, by acting on MT1 receptors, affects NeuroD expression in the gastrointestinal tract and thus might contribute to circadian regulation in metabolic functions.

  2. DMPD: Proximal effects of Toll-like receptor activation in dendritic cells. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17142025 Proximal effects of Toll-like receptor activation in dendritic cells. Watt...) (.svg) (.html) (.csml) Show Proximal effects of Toll-like receptor activation in dendritic cells. PubmedID... 17142025 Title Proximal effects of Toll-like receptor activation in dendritic ce

  3. Discoidin domain receptor 1 is activated independently of beta(1) integrin

    DEFF Research Database (Denmark)

    Vogel, W; Brakebusch, C; Fässler, R

    2000-01-01

    Various types of collagen have been identified as potential ligands for the two mammalian discoidin domain receptor (DDR) tyrosine kinases, DDR1 and DDR2. It is presently unclear whether collagen-induced DDR receptor activation, which occurs with very slow kinetics, involves additional proteins...... with kinase activity or membrane-anchored proteins serving as coreceptors. In particular, the role of the collagen-binding integrins alpha(1)beta(1) or alpha(2)beta(1) in the DDR activation process is undefined. Here, we provide three lines of evidence suggesting that DDR1 signaling is distinct from integrin...... activation. First we demonstrate that the enzymatic activity of DDR1 is essential for receptor tyrosine phosphorylation. Collagen-induced DDR receptor autophosphorylation can be blocked either by a dominant negative mutant or by a preparation of recombinant extracellular domain. Second, we show DDR1 signals...

  4. Allosteric activation of membrane-bound glutamate receptors using coordination chemistry within living cells

    Science.gov (United States)

    Kiyonaka, Shigeki; Kubota, Ryou; Michibata, Yukiko; Sakakura, Masayoshi; Takahashi, Hideo; Numata, Tomohiro; Inoue, Ryuji; Yuzaki, Michisuke; Hamachi, Itaru

    2016-10-01

    The controlled activation of proteins in living cells is an important goal in protein-design research, but to introduce an artificial activation switch into membrane proteins through rational design is a significant challenge because of the structural and functional complexity of such proteins. Here we report the allosteric activation of two types of membrane-bound neurotransmitter receptors, the ion-channel type and the G-protein-coupled glutamate receptors, using coordination chemistry in living cells. The high programmability of coordination chemistry enabled two His mutations, which act as an artificial allosteric site, to be semirationally incorporated in the vicinity of the ligand-binding pockets. Binding of Pd(2,2‧-bipyridine) at the allosteric site enabled the active conformations of the glutamate receptors to be stabilized. Using this approach, we were able to activate selectively a mutant glutamate receptor in live neurons, which initiated a subsequent signal-transduction pathway.

  5. Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR.

    Science.gov (United States)

    Calkin, Anna C; Tontonoz, Peter

    2012-03-14

    Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.

  6. Starring role of toll-like receptor-4 activation in the gutliver axis

    Institute of Scientific and Technical Information of China (English)

    Simone; Carotti; Michele; Pier; Luca; Guarino; Umberto; Vespasiani-Gentilucci; Sergio; Morini

    2015-01-01

    Since the introduction of the term "gut-liver axis", many studies have focused on the functional links of intestinal microbiota, barrier function and immune responses to liver physiology. Intestinal and extra-intestinal diseases alter microbiota composition and lead to dysbiosis, which aggravates impaired intestinal barrier function via increased lipopolysaccharide translocation. The subsequent increased passage of gut-derived product from the intestinal lumen to the organ wall and bloodstream affects gut motility and liver biology. The activation of the toll-like receptor 4(TLR-4) likely plays a key role in both cases. This review analyzed the most recent literature on the gut-liver axis, with a particular focus on the role of TLR-4 activation. Findings that linked liver disease with dysbiosis are evaluated, and links between dysbiosis and alterations of intestinal permeability and motility are discussed. We also examine the mechanisms of translocated gut bacteria and/or the bacterial product activation of liver inflammation and fibrogenesis via activity on different hepatic cell types.

  7. Social decisions affect neural activity to perceived dynamic gaze.

    Science.gov (United States)

    Latinus, Marianne; Love, Scott A; Rossi, Alejandra; Parada, Francisco J; Huang, Lisa; Conty, Laurence; George, Nathalie; James, Karin; Puce, Aina

    2015-11-01

    Gaze direction, a cue of both social and spatial attention, is known to modulate early neural responses to faces e.g. N170. However, findings in the literature have been inconsistent, likely reflecting differences in stimulus characteristics and task requirements. Here, we investigated the effect of task on neural responses to dynamic gaze changes: away and toward transitions (resulting or not in eye contact). Subjects performed, in random order, social (away/toward them) and non-social (left/right) judgment tasks on these stimuli. Overall, in the non-social task, results showed a larger N170 to gaze aversion than gaze motion toward the observer. In the social task, however, this difference was no longer present in the right hemisphere, likely reflecting an enhanced N170 to gaze motion toward the observer. Our behavioral and event-related potential data indicate that performing social judgments enhances saliency of gaze motion toward the observer, even those that did not result in gaze contact. These data and that of previous studies suggest two modes of processing visual information: a 'default mode' that may focus on spatial information; a 'socially aware mode' that might be activated when subjects are required to make social judgments. The exact mechanism that allows switching from one mode to the other remains to be clarified.

  8. Tasting calories differentially affects brain activation during hunger and satiety.

    Science.gov (United States)

    van Rijn, Inge; de Graaf, Cees; Smeets, Paul A M

    2015-02-15

    An important function of eating is ingesting energy. Our objectives were to assess whether oral exposure to caloric and non-caloric stimuli elicits discriminable responses in the brain and to determine in how far these responses are modulated by hunger state and sweetness. Thirty women tasted three stimuli in two motivational states (hunger and satiety) while their brain responses were measured using functional magnetic resonance imaging in a randomized crossover design. Stimuli were solutions of sucralose (sweet, no energy), maltodextrin (non-sweet, energy) and sucralose+maltodextrin (sweet, energy). We found no main effect of energy content and no interaction between energy content and sweetness. However, there was an interaction between hunger state and energy content in the median cingulate (bilaterally), ventrolateral prefrontal cortex, anterior insula and thalamus. This indicates that the anterior insula and thalamus, areas in which hunger state and taste of a stimulus are integrated, also integrate hunger state with caloric content of a taste stimulus. Furthermore, in the median cingulate and ventrolateral prefrontal cortex, tasting energy resulted in more activation during satiety compared to hunger. This finding indicates that these areas, which are known to be involved in processes that require approach and avoidance, are also involved in guiding ingestive behavior. In conclusion, our results suggest that energy sensing is a hunger state dependent process, in which the median cingulate, ventrolateral prefrontal cortex, anterior insula and thalamus play a central role by integrating hunger state with stimulus relevance.

  9. Cobalt in alluvial Egyptian soils as affected by industrial activities

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Twenty-five surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted,moderately and highly polluted soils. The aim of this study was to evaluate total Co content in alluvial soils of Delta in Egypt using the delayed Neturen activation analysis technique (DNAA). The two prominent gamma ray lines at 1173.2 and 1332.5 keV was efficiently used for 60Co determination. Co content in non-polluted soil samples ranged between 13.12 to 23.20 ppm Co with an average of 18.16*4.38 ppm. Cobalt content in moderately polluted soils ranged between 26.5 to 30.00 ppm with an average of 28.3*1.3 ppm. The highest Co levels (ranged from 36 to 64.69 ppm with an average of 51.9*9.5); were observed in soil samples collected from, either highly polluted agricultural soils due to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  10. Maturational alterations in constitutive activity of medial prefrontal cortex kappa-opioid receptors in Wistar rats.

    Science.gov (United States)

    Sirohi, Sunil; Walker, Brendan M

    2015-11-01

    Opioid receptors can display spontaneous agonist-independent G-protein signaling (basal signaling/constitutive activity). While constitutive κ-opioid receptor (KOR) activity has been documented in vitro, it remains unknown if KORs are constitutively active in native systems. Using [(35) S] guanosine 5'-O-[gamma-thio] triphosphate coupling assay that measures receptor functional state, we identified the presence of medial prefrontal cortex KOR constitutive activity in young rats that declined with age. Furthermore, basal signaling showed an age-related decline and was insensitive to neutral opioid antagonist challenge. Collectively, the present data are first to demonstrate age-dependent alterations in the medial prefrontal cortex KOR constitutive activity in rats and changes in the constitutive activity of KORs can differentially impact KOR ligand efficacy. These data provide novel insights into the functional properties of the KOR system and warrant further consideration of KOR constitutive activity in normal and pathophysiological behavior. Opioid receptors exhibit agonist-independent constitutive activity; however, kappa-opioid receptor (KOR) constitutive activity has not been demonstrated in native systems. Our results confirm KOR constitutive activity in the medial prefrontal cortex (mPFC) that declines with age. With the ability to presynaptically inhibit multiple neurotransmitter systems in the mPFC, maturational or patho-logical alterations in constitutive activity could disrupt corticofugal glutamatergic pyramidal projection neurons mediating executive function. Regulation of KOR constitutive activity could serve as a therapeutic target to treat compromised executive function.

  11. Activation, internalization, and recycling of the serotonin 2A receptor by dopamine

    Science.gov (United States)

    Bhattacharyya, Samarjit; Raote, Ishier; Bhattacharya, Aditi; Miledi, Ricardo; Panicker, Mitradas M.

    2006-01-01

    Serotonergic and dopaminergic systems, and their functional interactions, have been implicated in the pathophysiology of various CNS disorders. Here, we use recombinant serotonin (5-HT) 2A (5-HT2A) receptors to further investigate direct interactions between dopamine and 5-HT receptors. Previous studies in Xenopus oocytes showed that dopamine, although not the cognate ligand for the 5-HT2A receptor, acts as a partial-efficacy agonist. At micromolar concentrations, dopamine also acts as a partial-efficacy agonist on 5-HT2A receptors in HEK293 cells. Like 5-HT, dopamine also induces receptor-internalization in these cells, although at significantly higher concentrations than 5-HT. Interestingly, if the receptors are first sensitized or “primed” by subthreshold concentrations of 5-HT, then dopamine-induced internalization occurs at concentrations ≈10-fold lower than when dopamine is used alone. Furthermore, unlike 5-HT-mediated internalization, dopamine-mediated receptor internalization, alone, or after sensitization by 5-HT, does not depend on PKC. Dopamine-internalized receptors recycle to the surface at rates similar to those of 5-HT-internalized receptors. Our results suggest a previously uncharacterized role for dopamine in the direct activation and internalization of 5-HT2A receptors that may have clinical relevance to the function of serotonergic systems in anxiety, depression, and schizophrenia and also to the treatment of these disorders. PMID:17005723

  12. Megakaryocytes and platelets express nicotinic acetylcholine receptors but nicotine does not affect megakaryopoiesis or platelet function.

    Science.gov (United States)

    Schedel, Angelika; Kaiser, Kerstin; Uhlig, Stefanie; Lorenz, Florian; Sarin, Anip; Starigk, Julian; Hassmann, Dennis; Bieback, Karen; Bugert, Peter

    2016-01-01

    In our previous investigations we have shown that platelets and their precursors express nicotinic α7 acetylcholine receptors (nAChRα7) that are involved in platelet function and in vitro differentiation of the megakaryoblastic cell line MEG-01. In this study, we were interested in the expression analysis of additional nAChR and the effects of nicotine in an ex vivo model using megakaryocytic cells differentiated from cord blood derived CD34(+) cells (CBMK) and an in vivo model using blood samples from smokers. CBMK were differentiated with thrombopoietin (TPO) for up to 17 days. Quantitative real-time PCR (QRT-PCR), Western blot analysis and flow cytometry were used to investigate nAChR expression (nAChRα7, nAChRα4, nAChRβ2) and nicotine effects. In blood samples of 15 nonsmokers and 16 smokers platelet parameters (count, mean platelet volume--MPV and platelet distribution width--PDW) were determined as indicators for changes of in vivo megakaryopoiesis. Platelet function was determined by the use of whole blood aggregometry and flow cytometry. The functional role of nAChR was evaluated using specific antagonists in aggregometry. CHRNA7, CHRNA4 and CHRNB2 gene transcripts and the corresponding proteins could be identified in CBMK during all stages of differentiation. Platelets contain nAChRα7 and nAChRβ2 but not nAChRα4. Nicotine had no effect on TPO-induced differentiation of CBMK. There was no significant difference in all platelet parameters of the smokers compared to the nonsmokers. In line with this, cholinergic gene transcripts as well as the encoded proteins were equally expressed in both the study groups. Despite our observation of nAChR expression in megakaryopoiesis and platelets, we were not able to detect effects of nicotine in our ex vivo and in vivo models. Thus, the functional role of the nAChR in these cells remains open.

  13. Activated receptors for peroxisomic proliferators. Its role in the atherosclerosis, obesity and high blood pressure.

    Directory of Open Access Journals (Sweden)

    Mikhail Benet Rodríguez

    2004-08-01

    Full Text Available The receptors activated by peroxisome proliferators are a family of factors of transcription that belong to the superfamily of the steroid receptors and include tree subtypes which are PPARá, PPAR©¬ and PPAR ã. These receptors join to direct hexameric repetitions in the form of heterodimers with the retinoid receptor. PPAR receptors regulate the expressions of a great variety of genes that codify the proteins that are implied in the lipid metabolism, the energetic homeostasis, the cellular differentiation and the formation of tumours. This review describes the features, regulation and target genes of the PPAR receptor and the physiopathological and pharmacological implications of the regulation of the lipid and glucose metabolism, the energetic homeostasis ,hypertension and endothelial dysfunction.

  14. Inhibition of Protease-activated Receptor 1 Ameliorates Intestinal Radiation Mucositis in a Preclinical Rat Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junru; Kulkarni, Ashwini [Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Chintala, Madhu [Schering-Plough Research Institute, Kenilworth, New Jersey (United States); Fink, Louis M. [Nevada Cancer Institute, Las Vegas, Nevada (United States); Hauer-Jensen, Martin, E-mail: mhjensen@life.uams.edu [Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Surgery Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas (United States)

    2013-01-01

    Purpose: To determine, using a specific small-molecule inhibitor of protease-activated receptor 1 (PAR1) signaling, whether the beneficial effect of thrombin inhibition on radiation enteropathy development is due to inhibition of blood clotting or to cellular (PAR1-mediated) thrombin effects. Methods and Materials: Rats underwent fractionated X-irradiation (5 Gy Multiplication-Sign 9) of a 4-cm small-bowel segment. Early radiation toxicity was evaluated in rats receiving PAR1 inhibitor (SCH602539, 0, 10, or 15 mg/kg/d) from 1 day before to 2 weeks after the end of irradiation. The effect of PAR1 inhibition on development of chronic intestinal radiation fibrosis was evaluated in animals receiving SCH602539 (0, 15, or 30 mg/kg/d) until 2 weeks after irradiation, or continuously until termination of the experiment 26 weeks after irradiation. Results: Blockade of PAR1 ameliorated early intestinal toxicity, with reduced overall intestinal radiation injury (P=.002), number of myeloperoxidase-positive (P=.03) and proliferating cell nuclear antigen-positive (P=.04) cells, and collagen III accumulation (P=.005). In contrast, there was no difference in delayed radiation enteropathy in either the 2- or 26-week administration groups. Conclusion: Pharmacological blockade of PAR1 seems to reduce early radiation mucositis but does not affect the level of delayed intestinal radiation fibrosis. Early radiation enteropathy is related to activation of cellular thrombin receptors, whereas platelet activation or fibrin formation may play a greater role in the development of delayed toxicity. Because of the favorable side-effect profile, PAR1 blockade should be further explored as a method to ameliorate acute intestinal radiation toxicity in patients undergoing radiotherapy for cancer and to protect first responders and rescue personnel in radiologic/nuclear emergencies.

  15. In vitro translation of androgen receptor cRNA results in an activated androgen receptor protein

    NARCIS (Netherlands)

    G.G.J.M. Kuiper (George); P.E. de Ruiter (Petra); J. Trapman (Jan); G.W. Jenster (Guido); A.O. Brinkmann (Albert)

    1993-01-01

    textabstractTranslation of androgen receptor (AR) cRNA in a reticulocyte lysate and subsequent analysis of the translation products by SDS/PAGE showed a protein with an apparent molecular mass of 108 kDa. Scatchard-plot analysis revealed a single binding component with

  16. The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Olsen, Kristine Boisen; Erikstrup, Niels;

    2011-01-01

    The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately...

  17. Transcriptional activation by the thyroid hormone receptor through ligand-dependent receptor recruitment and chromatin remodelling

    DEFF Research Database (Denmark)

    Grøntved, Lars; Waterfall, Joshua J; Kim, Dong Wook;

    2015-01-01

    A bimodal switch model is widely used to describe transcriptional regulation by the thyroid hormone receptor (TR). In this model, the unliganded TR forms stable, chromatin-bound complexes with transcriptional co-repressors to repress transcription. Binding of hormone dissociates co-repressors and...

  18. Research Resource: Androgen Receptor Activity Is Regulated Through the Mobilization of Cell Surface Receptor Networks.

    Science.gov (United States)

    Hsiao, Jordy J; Ng, Brandon H; Smits, Melinda M; Martinez, Harryl D; Jasavala, Rohini J; Hinkson, Izumi V; Fermin, Damian; Eng, Jimmy K; Nesvizhskii, Alexey I; Wright, Michael E

    2015-08-01

    The aberrant expression of androgen receptor (AR)-dependent transcriptional programs is a defining pathology of the development and progression of prostate cancers. Transcriptional cofactors that bind AR are critical determinants of prostate tumorigenesis. To gain a deeper understanding of the proteins linked to AR-dependent gene transcription, we performed a DNA-affinity chromatography-based proteomic screen designed to identify proteins involved in AR-mediated gene transcription in prostate tumor cells. Functional experiments validated the coregulator roles of known AR-binding proteins in AR-mediated transcription in prostate tumor cells. More importantly, novel coregulatory functions were detected in components of well-established cell surface receptor-dependent signal transduction pathways. Further experimentation demonstrated that components of the TNF, TGF-β, IL receptor, and epidermal growth factor signaling pathways modulated AR-dependent gene transcription and androgen-dependent proliferation in prostate tumor cells. Collectively, our proteomic dataset demonstrates that the cell surface receptor- and AR-dependent pathways are highly integrated, and provides a molecular framework for understanding how disparate signal-transduction pathways can influence AR-dependent transcriptional programs linked to the development and progression of human prostate cancers.

  19. Activity-induced and developmental downregulation of the Nogo receptor

    DEFF Research Database (Denmark)

    Josephson, Anna; Trifunovski, Alexandra; Schéele, Camilla;

    2003-01-01

    The three axon growth inhibitory proteins, myelin associated glycoprotein, oligodendrocyte-myelin glycoprotein and Nogo-A, can all bind to the Nogo-66 receptor (NgR). This receptor is expressed by neurons with high amounts in regions of high plasticity where Nogo expression is also high. We...... hypothesized that simultaneous presence of high levels of Nogo and its receptor in neurons confers a locked state to hippocampal and cortical microcircuitry and that one or both of these proteins must be effectively and temporarily downregulated to permit plastic structural changes underlying formation of long...... that NgR levels in developing and adult neurons are regulated in vivo under different conditions. Strong, rapid and transient downregulation of NgR mRNA in response to kainic acid and after wheel running in cortex and hippocampus suggests a role for NgR and Nogo-A in plasticity, learning and memory....

  20. GABA-B receptor activation and conflict behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ketelaars, C.E.J.; Bollen, E.L.; Rigter, H.; Bruinvels, J.

    1988-01-01

    Baclofen and oxazepam enhance extinction of conflict behavior in the Geller-Seifter test while baclofen and diazepam release punished behavior in Vogel's conflict test. In order to investigate the possibility that the effect of the selective GABA-B receptor agonist baclofen is mediated indirectly via the GABA-A/benzodiazepine receptor complex, the effect of pretreatment of rats with baclofen on (/sup 3/H)-diazepam binding to washed and unwashed cortical and cerebellar membranes of rats has been studied. Baclofen pretreatment increase Bmax in washed cerebellar membranes when bicuculline was present in the incubation mixture. No effect was seen in cortical membranes. The present results render it unlikely that the effect of baclofen on extinction of conflict behavior and punished drinking is mediated via the GABA-A/benzodiazepine receptor complex. 50 references, 1 figure, 4 tables.

  1. G protein activation by G protein coupled receptors: ternary complex formation or catalyzed reaction?

    Science.gov (United States)

    Roberts, David J; Waelbroeck, Magali

    2004-09-01

    G protein coupled receptors catalyze the GDP/GTP exchange on G proteins, thereby activating them. The ternary complex model, designed to describe agonist binding in the absence of GTP, is often extended to G protein activation. This is logically unsatisfactory as the ternary complex does not accumulate when G proteins are activated by GTP. Extended models taking into account nucleotide binding exist, but fail to explain catalytic G protein activation. This review puts forward an enzymatic model of G protein activation and compares its predictions with the ternary complex model and with observed receptor phenomenon. This alternative model does not merely provide a new set of formulae but leads to a new philosophical outlook and more readily accommodates experimental observations. The ternary complex model implies that, HRG being responsible for efficient G protein activation, it should be as stable as possible. In contrast, the enzyme model suggests that although a limited stabilization of HRG facilitates GDP release, HRG should not be "too stable" as this might trap the G protein in an inactive state and actually hinder G protein activation. The two models also differ completely in the definition of the receptor "active state": the ternary complex model implies that the active state corresponds to a single active receptor conformation (HRG); in contrast, the catalytic model predicts that the active receptor state is mobile, switching smoothly through various conformations with high and low affinities for agonists (HR, HRG, HRGGDP, HRGGTP, etc.).

  2. Looking for reward in all the wrong places: dopamine receptor gene polymorphisms indirectly affect aggression through sensation-seeking.

    Science.gov (United States)

    Chester, David S; DeWall, C Nathan; Derefinko, Karen J; Estus, Steven; Lynam, Donald R; Peters, Jessica R; Jiang, Yang

    2016-10-01

    Individuals with genotypes that code for reduced dopaminergic brain activity often exhibit a predisposition toward aggression. However, it remains largely unknown how dopaminergic genotypes may increase aggression. Lower-functioning dopamine systems motivate individuals to seek reward from external sources such as illicit drugs and other risky experiences. Based on emerging evidence that aggression is a rewarding experience, we predicted that the effect of lower-functioning dopaminergic functioning on aggression would be mediated by tendencies to seek the environment for rewards. Caucasian female and male undergraduates (N = 277) were genotyped for five polymorphisms of the dopamine D2 receptor (DRD2) gene; they reported their previous history of aggression and their dispositional reward-seeking. Lower-functioning DRD2 profiles were associated with greater sensation-seeking, which then predicted greater aggression. Our findings suggest that lower-functioning dopaminergic activity puts individuals at risk for violence because it motivates them to experience aggression's hedonically rewarding qualities.

  3. Peripheral Sensitization Increases Opioid Receptor Expression and Activation by Crotalphine in Rats

    Science.gov (United States)

    Zambelli, Vanessa Olzon; Fernandes, Ana Carolina de Oliveira; Gutierrez, Vanessa Pacciari; Ferreira, Julio Cesar Batista; Parada, Carlos Amilcar; Mochly-Rosen, Daria; Cury, Yara

    2014-01-01

    Inflammation enhances the peripheral analgesic efficacy of opioid drugs, but the mechanisms involved in this phenomenon have not been fully elucidated. Crotalphine (CRP), a peptide that was first isolated from South American rattlesnake C.d. terrificus venom, induces a potent and long-lasting anti-nociceptive effect that is mediated by the activation of peripheral opioid receptors. Because the high efficacy of CRP is only observed in the presence of inflammation, we aimed to elucidate the mechanisms involved in the CRP anti-nociceptive effect induced by inflammation. Using real-time RT-PCR, western blot analysis and ELISA assays, we demonstrate that the intraplantar injection of prostaglandin E2 (PGE2) increases the mRNA and protein levels of the µ- and κ-opioid receptors in the dorsal root ganglia (DRG) and paw tissue of rats within 3 h of the injection. Using conformation state-sensitive antibodies that recognize activated opioid receptors, we show that PGE2, alone does not increase the activation of these opioid receptors but that in the presence of PGE2, the activation of specific opioid receptors by CRP and selective µ- and κ-opioid receptor agonists (positive controls) increases. Furthermore, PGE2 down-regulated the expression and activation of the δ-opioid receptor. CRP increased the level of activated mitogen-activated protein kinases in cultured DRG neurons, and this increase was dependent on the activation of protein kinase Cζ. This CRP effect was much more prominent when the cells were pretreated with PGE2. These results indicate that the expression and activation of peripheral opioid receptors by opioid-like drugs can be up- or down-regulated in the presence of an acute injury and that acute tissue injury enhances the efficacy of peripheral opioids. PMID:24594607

  4. Prostate stem cell antigen interacts with nicotinic acetylcholine receptors and is affected in Alzheimer's disease

    DEFF Research Database (Denmark)

    Jensen, Majbrit M; Arvaniti, Maria; Mikkelsen, Jens D;

    2015-01-01

    and modulating their function. Hence, changes in nAChR regulatory proteins such as Lynx proteins could underlie the dysregulation of nAChRs in AD. Using Western blotting, we detected bands corresponding to the Lynx proteins prostate stem cell antigen (PSCA) and Lypd6 in human cortex indicating that both proteins...... are present in the human brain. We further showed that PSCA forms stable complexes with the α4 nAChR subunit and decreases nicotine-induced extracellular-signal regulated kinase phosphorylation in PC12 cells. In addition, we analyzed protein levels of PSCA and Lypd6 in postmortem tissue of medial frontal...... human transgenes that cause both age-dependent β-amyloidosis and tauopathy, whereas Tg2576 mice, which display β-amyloidosis only, had unchanged PSCA levels compared to wild-type animals. These findings identify PSCA as a nAChR-binding protein in the human brain that is affected in AD, suggesting...

  5. Effects related to gene-gene interactions of peroxisome proliferator-activated receptor on essential hypertension

    Institute of Scientific and Technical Information of China (English)

    俞浩

    2013-01-01

    Objective To explore the impact of the gene-gene interaction among the single nucleotide polymorphisms(SNPs) of peroxisome proliferator-activated receptorα/δ/γ on essential hypertension(EH).Methods

  6. Chronic regulation of colonic epithelial secretory function by activation of G protein-coupled receptors.

    LENUS (Irish Health Repository)

    Toumi, F

    2011-02-01

    Enteric neurotransmitters that act at G protein-coupled receptors (GPCRs) are well known to acutely promote epithelial Cl(-) and fluid secretion. Here we examined if acute GPCR activation might have more long-term consequences for epithelial secretory function.

  7. An Angiotensin II type 1 receptor activation switch patch revealed through Evolutionary Trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong

    2010-01-01

    in the cytoplasmic parts of TM2, TM3, and TM6 to form an activation switch that is common to all family A 7TM receptors. We tested this hypothesis in the rat Angiotensin II (Ang II) type 1a (AT1a) receptor. The receptor has important roles in the cardiovascular system, but has also frequently been applied as a model......) displayed phenotypes associated with changed activation state, such as increased agonist affinity or basal activity, promiscuous activation, or constitutive internalization highlighting the importance of testing different signaling pathways. We conclude that this evolutionary important patch mediates...... to be completely resolved. Evolutionary Trace (ET) analysis is a computational method, which identifies clusters of functionally important residues by integrating information on evolutionary important residue variations with receptor structure. Combined with known mutational data, ET predicted a patch of residues...

  8. The importance of physical activity and sleep for affect on stressful days: Two intensive longitudinal studies.

    Science.gov (United States)

    Flueckiger, Lavinia; Lieb, Roselind; Meyer, Andrea H; Witthauer, Cornelia; Mata, Jutta

    2016-06-01

    We investigated the potential stress-buffering effect of 3 health behaviors-physical activity, sleep quality, and snacking-on affect in the context of everyday life in young adults. In 2 intensive longitudinal studies with up to 65 assessment days over an entire academic year, students (Study 1, N = 292; Study 2, N = 304) reported stress intensity, sleep quality, physical activity, snacking, and positive and negative affect. Data were analyzed using multilevel regression analyses. Stress and positive affect were negatively associated; stress and negative affect were positively associated. The more physically active than usual a person was on a given day, the weaker the association between stress and positive affect (Study 1) and negative affect (Studies 1 and 2). The better than usual a person's sleep quality had been during the previous night, the weaker the association between stress and positive affect (Studies 1 and 2) and negative affect (Study 2). The association between daily stress and positive or negative affect did not differ as a function of daily snacking (Studies 1 and 2). On stressful days, increasing physical activity or ensuring high sleep quality may buffer adverse effects of stress on affect in young adults. These findings suggest potential targets for health-promotion and stress-prevention programs, which could help reduce the negative impact of stress in young adults. (PsycINFO Database Record

  9. Altered activity profile of a tertiary silanol analog of multi-targeting nuclear receptor modulator T0901317.

    Science.gov (United States)

    Toyama, Hirozumi; Sato, Shoko; Shirakawa, Hitoshi; Komai, Michio; Hashimoto, Yuichi; Fujii, Shinya

    2016-04-01

    We report the design, synthesis, and physicochemical/biological evaluation of novel silanol derivative 6 (sila-T) as a silanol analog of multi-target nuclear receptor modulator T0901317 (5). Compound 6 showed intermediate hydrophobicity between the corresponding alcohol 13 and perfluoroalcohol 5. While 5 exhibited potent activities toward liver X receptor α and β, farnesoid X receptor, pregnane X receptor (PXR) and retinoic acid receptor-related orphan receptor (ROR)γ, silanol 6 exhibited activity only toward PXR and RORs. Incorporation of silanol instead of perfluoroalcohol is a promising option for developing novel target-selective, biologically active compounds.

  10. Identification of (beta-carboxyethyl)-rhodanine derivatives exhibiting peroxisome proliferator-activated receptor gamma activity.

    Science.gov (United States)

    Choi, Jiwon; Ko, Yoonae; Lee, Hui Sun; Park, Yun Sun; Yang, Young; Yoon, Sukjoon

    2010-01-01

    We applied an improved virtual screening scheme combining ligand-centric and receptor-centric methods for the identification of a new series of PPARgamma agonists known as (beta-carboxyethyl)-rhodanine derivatives which include a thiazolidin-based core structure, 2-thioxo-thiazolidine-4-one. An in vitro assay confirmed the nanomolar binding affinity in one of the (beta-carboxyethyl)-rhodanine derivatives, SP1818. It showed a PPARgamma agonistic activity similar to that of a known PPARgamma drug, pioglitazone, in a cell-based transactivation assay. Furthermore, the structure-activity relationships of the rhodanine derivatives were investigated through comparative molecular field analysis. We also characterized the inconsistency between the in vitro binding affinity and cell-based transactivation ability by using a set of property-based molecular descriptors. The binding mode analysis provided new insight concerning their agonistic effect on PPARgamma.

  11. Mapping transmembrane residues of proteinase activated receptor 2 (PAR2) that influence ligand-modulated calcium signaling.

    Science.gov (United States)

    Suen, J Y; Adams, M N; Lim, J; Madala, P K; Xu, W; Cotterell, A J; He, Y; Yau, M K; Hooper, J D; Fairlie, D P

    2017-03-01

    Proteinase-activated receptor 2 (PAR2) is a G protein-coupled receptor involved in metabolism, inflammation, and cancers. It is activated by proteolysis, which exposes a nascent N-terminal sequence that becomes a tethered agonist. Short synthetic peptides corresponding to this sequence also activate PAR2, while small organic molecules show promising PAR2 antagonism. Developing PAR2 ligands into pharmaceuticals is hindered by a lack of knowledge of how synthetic ligands interact with and differentially modulate PAR2. Guided by PAR2 homology modeling and ligand docking based on bovine rhodopsin, followed by cross-checking with newer PAR2 models based on ORL-1 and PAR1, site-directed mutagenesis of PAR2 was used to investigate the pharmacology of three agonists (two synthetic agonists and trypsin-exposed tethered ligand) and one antagonist for modulation of PAR2 signaling. Effects of 28 PAR2 mutations were examined for PAR2-mediated calcium mobilization and key mutants were selected for measuring ligand binding. Nineteen of twenty-eight PAR2 mutations reduced the potency of at least one ligand by >10-fold. Key residues mapped predominantly to a cluster in the transmembrane (TM) domains of PAR2, differentially influence intracellular Ca(2+) induced by synthetic agonists versus a native agonist, and highlight subtly different TM residues involved in receptor activation. This is the first evidence highlighting the importance of the PAR2 TM regions for receptor activation by synthetic PAR2 agonists and antagonists. The trypsin-cleaved N-terminus that activates PAR2 was unaffected by residues that affected synthetic peptides, challenging the widespread practice of substituting peptides for proteases to characterize PAR2 physiology.

  12. Cloning and molecular analysis of genes affecting expression of binding substance, the recipient-encoded receptor(s) mediating mating aggregate formation in Enterococcus faecalis.

    Science.gov (United States)

    Bensing, B A; Dunny, G M

    1993-11-01

    Transfer of the conjugative plasmid pCF10 in Enterococcus faecalis strains involves production of a plasmid-encoded aggregation substance on the surface of donor cells in response to stimulation by a pheromone secreted by recipient cells. Aggregation substance then facilitates attachment to recipient cells via a chromosomally encoded receptor, termed binding substance (BS). A BS mutant, strain INY3000, generated by random Tn916 insertions, was previously found to carry copies of the transposon at four unique sites (K. M. Trotter and G. M. Dunny, Plasmid 24:57-67, 1990). In the present study, DNA flanking the Tn916 insertions was used to complement the BS mutation of INY3000 following Tn916 excision from cloned chromosomal fragments. Complementation results showed that three of the four regions mutated in INY3000 play some role in BS expression. Tn5 mutagenesis and DNA sequence analysis of the complementing fragment from one of these regions indicated the presence of three genes (ebsA, ebsB, and ebsC) that affect BS expression. The ebsA and ebsB genes encode peptides likely to function in cell wall metabolism, whereas ebsC may encode a product that suppresses the function or expression of EbsB.

  13. Structural and functional characterization of alternative transmembrane domain conformations in VEGF receptor 2 activation.

    Science.gov (United States)

    Manni, Sandro; Mineev, Konstantin S; Usmanova, Dinara; Lyukmanova, Ekaterina N; Shulepko, Mikhail A; Kirpichnikov, Mikhail P; Winter, Jonas; Matkovic, Milos; Deupi, Xavier; Arseniev, Alexander S; Ballmer-Hofer, Kurt

    2014-08-05

    Transmembrane signaling by receptor tyrosine kinases (RTKs) entails ligand-mediated dimerization and structural rearrangement of the extracellular domains. RTK activation also depends on the specific orientation of the transmembrane domain (TMD) helices, as suggested by pathogenic, constitutively active RTK mutants. Such mutant TMDs carry polar amino acids promoting stable transmembrane helix dimerization, which is essential for kinase activation. We investigated the effect of polar amino acids introduced into the TMD of vascular endothelial growth factor receptor 2, regulating blood vessel homeostasis. Two mutants showed constitutive kinase activity, suggesting that precise TMD orientation is mandatory for kinase activation. Nuclear magnetic resonance spectroscopy revealed that TMD helices in activated constructs were rotated by 180° relative to the interface of the wild-type conformation, confirming that ligand-mediated receptor activation indeed results from transmembrane helix rearrangement. A molecular dynamics simulation confirmed the transmembrane helix arrangement of wild-type and mutant TMDs revealed by nuclear magnetic resonance spectroscopy.

  14. The phosphoproteome of toll-like receptor-activated macrophages

    DEFF Research Database (Denmark)

    Weintz, Gabriele; Olsen, Jesper Velgaard; Frühauf, Katja;

    2010-01-01

    Recognition of microbial danger signals by toll-like receptors (TLR) causes re-programming of macrophages. To investigate kinase cascades triggered by the TLR4 ligand lipopolysaccharide (LPS) on systems level, we performed a global, quantitative and kinetic analysis of the phosphoproteome...

  15. Obstructing Androgen Receptor Activation in Prostate Cancer Cells Through Post-translational Modification by NEDD8

    Science.gov (United States)

    2012-11-01

    Nonidet P - 40 ). Pre-cleared with 25 µl protein-A/G agarose beads, 700 µg lysate was subjected to immunoprecipitation with 20 µl anti-FLAG antibody...cell growth. REPORTABLE OUTCOMES: 1. Chang, K. H., Hsiao, P .-W. and Chen, J. D. Modulation of Androgen Receptor Activity by Reversible NEDD8...Hsiao, P .-W. and Chen, J. D. Modulation of Androgen Receptor Activity by Reversible NEDD8 Modification. (under revision) 1 Modulation of

  16. Estradiol increases the anorexia associated with increased 5-HT2C receptor activation in ovariectomized rats

    OpenAIRE

    Rivera, Heidi M.; Santollo, Jessica; Nikonova, Larissa V.; Eckel, Lisa A.

    2011-01-01

    Estradiol’s inhibitory effect on food intake is mediated, in part, by its ability to increase the activity of meal-related signals, including serotonin (5-HT), which hasten satiation. The important role that postsynaptic 5-HT2C receptors play in mediating 5-HT’s anorexigenic effect prompted us to investigate whether a regimen of acute estradiol treatment increases the anorexia associated with increased 5-HT2C receptor activation in ovariectomized (OVX) rats. We demonstrated that intraperitone...

  17. Regulation of breast cancer stem cell activity by signaling through the Notch4 receptor

    OpenAIRE

    Harrison, Hannah; Farnie, Gillian; Howell, Sacha J.; Rock, Rebecca E; Stylianou, Spyros; Brennan, Keith R.; Bundred, Nigel J; Clarke, Robert B.

    2010-01-01

    Notch receptor signaling pathways play an important role not only in normal breast development but also in breast cancer development and progression. We assessed the role of Notch receptors in stem cell activity in breast cancer cell lines and nine primary human tumor samples. Stem cells were enriched by selection of anoikis-resistant cells or cells expressing the membrane phenotype ESA+/CD44+/CD24low. Using these breast cancer stem cell populations, we compared the activation status of Notch...