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Sample records for activin receptors

  1. Cripto forms a complex with activin and type II activin receptors and can block activin signaling

    Science.gov (United States)

    Gray, Peter C.; Harrison, Craig A.; Vale, Wylie

    2003-01-01

    Activin, nodal, Vg1, and growth and differentiation factor 1 are members of the transforming growth factor β superfamily and signal via the activin type II (ActRII/IIB) and type I (ALK4) serine/threonine kinase receptors. Unlike activins, however, signaling by nodal, Vg1, and growth and differentiation factor 1 requires a coreceptor from the epidermal growth factor-Cripto-FRL1-Cryptic protein family such as Cripto. Cripto has important roles during development and oncogenesis and binds nodal or related ligands and ALK4 to facilitate assembly of type I and type II receptor signaling complexes. Because Cripto mediates signaling via activin receptors and binds directly to ALK4, we tested whether transfection with Cripto would affect the ability of activin to signal and/or interact with its receptors. Here we show that Cripto can form a complex with activin and ActRII/IIB. We were unable to detect activin binding to Cripto in the absence of ActRII/IIB, indicating that unlike nodal, activin requires type II receptors to bind Cripto. If cotransfected with ActRII/IIB and ALK4, Cripto inhibited crosslinking of activin to ALK4 and the association of ALK4 with ActRII/IIB. In addition, Cripto blocked activin signaling when transfected into either HepG2 cells or 293T cells. We have also shown that under conditions in which Cripto facilitates nodal signaling, it antagonizes activin. Inhibition of activin signaling provides an additional example of a Cripto effect on the regulation of signaling by transforming growth factor-β superfamily members. Because activin is a potent inhibitor of cell growth in multiple cell types, these results provide a mechanism that may partially explain the oncogenic action of Cripto. PMID:12682303

  2. Uterine-embryonic interaction in pit : activin, follistatin, and activin receptor II in uterus and embryo during early gestation

    NARCIS (Netherlands)

    Pavert, van de S.A.; Boerjan, M.L.; Stroband, H.W.J.; Taverne, M.A.M.; Hurk, van der R.

    2001-01-01

    The mRNA expression patterns of activin A and follistatin in the uterus and embryo, the mRNA expression of the activin receptor II in the embryo, and the localization in the uterus of the immunoreactive activin A and the receptor II proteins in the uterus were examined at gestation days 7-12 after o

  3. R-Smad competition controls activin receptor output in Drosophila.

    Directory of Open Access Journals (Sweden)

    Aidan J Peterson

    Full Text Available Animals use TGF-β superfamily signal transduction pathways during development and tissue maintenance. The superfamily has traditionally been divided into TGF-β/Activin and BMP branches based on relationships between ligands, receptors, and R-Smads. Several previous reports have shown that, in cell culture systems, "BMP-specific" Smads can be phosphorylated in response to TGF-β/Activin pathway activation. Using Drosophila cell culture as well as in vivo assays, we find that Baboon, the Drosophila TGF-β/Activin-specific Type I receptor, can phosphorylate Mad, the BMP-specific R-Smad, in addition to its normal substrate, dSmad2. The Baboon-Mad activation appears direct because it occurs in the absence of canonical BMP Type I receptors. Wing phenotypes generated by Baboon gain-of-function require Mad, and are partially suppressed by over-expression of dSmad2. In the larval wing disc, activated Baboon cell-autonomously causes C-terminal Mad phosphorylation, but only when endogenous dSmad2 protein is depleted. The Baboon-Mad relationship is thus controlled by dSmad2 levels. Elevated P-Mad is seen in several tissues of dSmad2 protein-null mutant larvae, and these levels are normalized in dSmad2; baboon double mutants, indicating that the cross-talk reaction and Smad competition occur with endogenous levels of signaling components in vivo. In addition, we find that high levels of Activin signaling cause substantial turnover in dSmad2 protein, providing a potential cross-pathway signal-switching mechanism. We propose that the dual activity of TGF-β/Activin receptors is an ancient feature, and we discuss several ways this activity can modulate TGF-β signaling output.

  4. Activin Receptor Signaling Regulates Prostatic Epithelial Cell Adhesion and Viability

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    Derek P. Simon

    2009-04-01

    Full Text Available Mutational changes coupled with endocrine, paracrine, and/or autocrine signals regulate cell division during carcinogenesis. The hormone signals remain undefined, although the absolute requirement in vitro for fetal serum indicates the necessity for a fetal serum factor(s in cell proliferation. Using prostatic cancer cell (PCC lines as a model of cancer cell proliferation, we have identified the fetal serum component activin A and its signaling through the activin receptor type II (ActRII, as necessary, although not sufficient, for PCC proliferation. Activin A induced Smad2 phosphorylation and PCC proliferation, but only in the presence of fetal bovine serum (FBS. Conversely, activin A antibodies and inhibin A suppressed FBS-induced PCC proliferation confirming activin A as one of multiple serum components required for PCC proliferation. Basic fibroblast growth factor was subsequently shown to synergize activin A-induced PCC proliferation. Inhibition of ActRII signaling using a blocking antibody or antisense-P decreased mature ActRII expression, Smad2 phosphorylation, and the apparent viability of PCCs and neuroblastoma cells grown in FBS. Suppression of ActRII signaling in PCC and neuroblastoma cells did not induce apoptosis as indicated by the ratio of active/inactive caspase 3 but did correlate with increased cell detachment and ADAM-15 expression, a disintegrin whose expression is strongly correlated with prostatic metastasis. These findings indicate that ActRII signaling is required for PCC and neuroblastoma cell viability, with ActRII mediating cell fate via the regulation of cell adhesion. That ActRII signaling governs both cell viability and cell adhesion has important implications for developing therapeutic strategies to regulate cancer growth and metastasis.

  5. Activin receptor subunits in normal and dysfunctional adult human testis

    DEFF Research Database (Denmark)

    Dias, V; Meachem, S; Rajpert-De Meyts, E

    2008-01-01

    The cellular sites of activin action and its regulation in the normal and dysfunctional adult human testis are unknown.......The cellular sites of activin action and its regulation in the normal and dysfunctional adult human testis are unknown....

  6. Activin receptor signaling regulates cocaine-primed behavioral and morphological plasticity.

    Science.gov (United States)

    Gancarz, Amy M; Wang, Zi-Jun; Schroeder, Gabrielle L; Damez-Werno, Diane; Braunscheidel, Kevin M; Mueller, Lauren E; Humby, Monica S; Caccamise, Aaron; Martin, Jennifer A; Dietz, Karen C; Neve, Rachael L; Dietz, David M

    2015-07-01

    Activin receptor signaling, including the transcription factor Smad3, was upregulated in the rat nucleus accumbens (NAc) shell following withdrawal from cocaine. Direct genetic and pharmacological manipulations of this pathway bidirectionally altered cocaine seeking while governing morphological plasticity in NAc neurons. Thus, Activin/Smad3 signaling is induced following withdrawal from cocaine, and such regulation may be a key molecular mechanism underlying behavioral and cellular plasticity in the brain following cocaine self-administration.

  7. An Activin Receptor IA/Activin-Like Kinase-2 (R206H Mutation in Fibrodysplasia Ossificans Progressiva

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    Rafael Herrera-Esparza

    2013-01-01

    Full Text Available Fibrodysplasia ossificans progressiva (FOP is an exceptionally rare genetic disease that is characterised by congenital malformations of the great toes and progressive heterotopic ossification (HO in specific anatomical areas. This disease is caused by a mutation in activin receptor IA/activin-like kinase-2 (ACVR1/ALK2. A Mexican family with one member affected by FOP was studied. The patient is a 19-year-old female who first presented with symptoms of FOP at 8 years old; she developed spontaneous and painful swelling of the right scapular area accompanied by functional limitation of movement. Mutation analysis was performed in which genomic DNA as PCR amplified using primers flanking exons 4 and 6, and PCR products were digested with Cac8I and HphI restriction enzymes. The most informative results were obtained with the exon 4 flanking primers and the Cac8I restriction enzyme, which generated a 253 bp product that carries the ACVR1 617G>A mutation, which causes an amino acid substitution of histidine for arginine at position 206 of the glycine-serine (GS domain, and its mutation results in the dysregulation of bone morphogenetic protein (BMP signalling that causes FOP.

  8. Inhibin subunits, follistatin and activin receptors in the human teratocarcinoma cell line Tera-2.

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    de Jong, F H; de Winter, J P; Wesseling, J G; Timmerman, M A; van Genesen, S; van den Eijnden-van Raaij, A J; van Zoelen, E J

    1993-05-14

    The expression of mRNAs for inhibin subunits was studied in the human teratocarcinoma cell line Tera-2 clone 13 before and after differentiation with retinoic acid (RA). Both alpha- and beta B-subunits of inhibin were expressed. Subsequently, inhibin bio- and immunoactivity in the conditioned media of the Tera-2 cells were determined by studying the release of follicle-stimulating hormone from rat pituitary cells, by immunoassay and by immunoprecipitation using inhibin alpha- and beta B-subunit specific antibodies. Strikingly dissimilar high bio- and low immuno-activities were found. The ensuing hypothesis that the high bioactivity might be due to the presence of the activin-binding protein follistatin was confirmed by immunoprecipitation of 34 and 37 kDa labelled proteins, using a polyclonal anti-follistatin antiserum after culture of the Tera-2 cells with [35S]-methionine. Furthermore, expression of activin receptor types II and IIB mRNA was found in the cells. Addition of 5 microM RA to monolayer cultures of Tera-2 cells resulted in differentiation to flat endoderm-like cells and caused a slight suppression of the expression of the mRNA encoding the inhibin alpha- and beta B-subunits. The expression of follistatin and activin receptor type IIB was strongly suppressed, whereas the expression of the activin receptor type II was not affected. We conclude that Tera-2 cells secrete follistatin and express inhibin subunits and activin receptors differentially during RA-induced differentiation. The role of the decreased expression of follistatin and activin receptor IIB mRNA after addition of RA in the mechanism of RA-induced differentiation remains to be elucidated.

  9. An antibody blocking activin type II receptors induces strong skeletal muscle hypertrophy and protects from atrophy.

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    Lach-Trifilieff, Estelle; Minetti, Giulia C; Sheppard, KellyAnn; Ibebunjo, Chikwendu; Feige, Jerome N; Hartmann, Steffen; Brachat, Sophie; Rivet, Helene; Koelbing, Claudia; Morvan, Frederic; Hatakeyama, Shinji; Glass, David J

    2014-02-01

    The myostatin/activin type II receptor (ActRII) pathway has been identified to be critical in regulating skeletal muscle size. Several other ligands, including GDF11 and the activins, signal through this pathway, suggesting that the ActRII receptors are major regulatory nodes in the regulation of muscle mass. We have developed a novel, human anti-ActRII antibody (bimagrumab, or BYM338) to prevent binding of ligands to the receptors and thus inhibit downstream signaling. BYM338 enhances differentiation of primary human skeletal myoblasts and counteracts the inhibition of differentiation induced by myostatin or activin A. BYM338 prevents myostatin- or activin A-induced atrophy through inhibition of Smad2/3 phosphorylation, thus sparing the myosin heavy chain from degradation. BYM338 dramatically increases skeletal muscle mass in mice, beyond sole inhibition of myostatin, detected by comparing the antibody with a myostatin inhibitor. A mouse version of the antibody induces enhanced muscle hypertrophy in myostatin mutant mice, further confirming a beneficial effect on muscle growth beyond myostatin inhibition alone through blockade of ActRII ligands. BYM338 protects muscles from glucocorticoid-induced atrophy and weakness via prevention of muscle and tetanic force losses. These data highlight the compelling therapeutic potential of BYM338 for the treatment of skeletal muscle atrophy and weakness in multiple settings.

  10. Regulation of muscle growth by multiple ligands signaling through activin type II receptors

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    Lee, Se-Jin; Reed, Lori A.; Davies, Monique V.; Girgenrath, Stefan; Goad, Mary E. P.; Tomkinson, Kathy N.; Wright, Jill F.; Barker, Christopher; Ehrmantraut, Gregory; Holmstrom, James; Trowell, Betty; Gertz, Barry; Jiang, Man-Shiow; Sebald, Suzanne M.; Matzuk, Martin; Li, En; Liang, Li-fang; Quattlebaum, Edwin; Stotish, Ronald L.; Wolfman, Neil M.

    2005-01-01

    Myostatin is a secreted protein that normally functions as a negative regulator of muscle growth. Agents capable of blocking the myostatin signaling pathway could have important applications for treating human muscle degenerative diseases as well as for enhancing livestock production. Here we describe a potent myostatin inhibitor, a soluble form of the activin type IIB receptor (ACVR2B), which can cause dramatic increases in muscle mass (up to 60% in 2 weeks) when injected into wild-type mice. Furthermore, we show that the effect of the soluble receptor is attenuated but not eliminated in Mstn-/- mice, suggesting that at least one other ligand in addition to myostatin normally functions to limit muscle growth. Finally, we provide genetic evidence that these ligands signal through both activin type II receptors, ACVR2 and ACVR2B, to regulate muscle growth in vivo. PMID:16330774

  11. Activins and activin antagonists in hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Alev Deli; Emanuel Kreidl; Stefan Santifaller; Barbara Trotter; Katja Seir; Walter Berger; Rolf Schulte-Hermann; Chantal Rodgarkia-Dara; Michael Grusch

    2008-01-01

    In many parts of the world hepatocellular carcinoma (HCC) is among the leading causes of cancer-related mortality but the underlying molecular pathology is still insufficiently understood. There is increasing evidence that activins, which are members of the transforming growth factor β (TGFβ) superfamily of growth and differentiation factors, could play important roles in liver carcinogenesis. Activins are disulphide-linked homo-or heterodimers formed from four different β subunits termed βA, βB, βC, and βE, respectively. Activin A, the dimer of two βA subunits, is critically involved in the regulation of cell growth, apoptosis, and tissue architecture in the liver, while the hepatic function of other activins is largely unexplored so far. Negative regulators of activin signals include antagonists in the extracellular space like the binding proteins follistatin and FLRG, and at the cell membrane antagonistic co-receptors like Cripto or BAMBI. Additionally, in the intracellular space inhibitory Smads can modulate and control activin activity. Accumulating data suggest that deregulation of activin signals contributes to pathologic conditions such as chronic inflammation, fibrosis and development of cancer. The current article reviews the alterations in components of the activin signaling pathway that have been observed in HCC and discusses their potential significance for liver tumorigenesis.

  12. Activin receptor subunits in normal and dysfunctional adult human testis

    DEFF Research Database (Denmark)

    Dias, V.; Meachem, S.; Rajpert-De, Meyts E.

    2008-01-01

    , carcinoma in situ (CIS), seminoma, non-seminoma and gonadotropin-deprived human testis. ActRIIA mRNA was localized by in situ hybridization. RESULTS: ALK2, ALK4 and ActRIIB proteins were observed in Sertoli cells, spermatogonia and some spermatocytes within normal and gonadotropin-suppressed adult human...... testis; all three receptor subunits were also detected in CIS, seminoma and non-seminoma cells. ActRIIA immunoreactivity was faint to absent in the normal testis and in CIS and non-seminoma cells, whereas some seminoma cells displayed a strong signal. Also in contrast to the normal testis, a majority...

  13. RAP-011, an activin receptor ligand trap, increases hemoglobin concentration in hepcidin transgenic mice.

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    Langdon, Jacqueline M; Barkataki, Sangjucta; Berger, Alan E; Cheadle, Chris; Xue, Qian-Li; Sung, Victoria; Roy, Cindy N

    2015-01-01

    Over expression of hepcidin antimicrobial peptide is a common feature of iron-restricted anemia in humans. We investigated the erythroid response to either erythropoietin or RAP-011, a "murinized" ortholog of sotatercept, in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. Sotatercept, a soluble, activin receptor type IIA ligand trap, is currently being evaluated for the treatment of anemias associated with chronic renal disease, myelodysplastic syndrome, β-thalassemia, and Diamond Blackfan anemia and acts by inhibiting signaling downstream of activin and other Transforming Growth Factor-β superfamily members. We found that erythropoietin and RAP-011 increased hemoglobin concentration in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. While erythropoietin treatment depleted splenic iron stores in C57BL/6 mice, RAP-011 treatment did not deplete splenic iron stores in mice of either genotype. Bone marrow erythroid progenitors from erythropoietin-treated mice exhibited iron-restricted erythropoiesis, as indicated by increased median fluorescence intensity of transferrin receptor immunostaining by flow cytometry. In contrast, RAP-011-treated mice did not exhibit the same degree of iron-restricted erythropoiesis. In conclusion, we have demonstrated that RAP-011 can improve hemoglobin concentration in hepcidin antimicrobial peptide 1 transgenic mice. Our data support the hypothesis that RAP-011 has unique biologic effects which prevent or circumvent depletion of mouse splenic iron stores. RAP-011 may, therefore, be an appropriate therapeutic for trials in human anemias characterized by increased expression of hepcidin antimicrobial peptide and iron-restricted erythropoiesis. © 2014 Wiley Periodicals, Inc.

  14. MiR-125b Regulates Primordial Follicle Assembly by Targeting Activin Receptor Type 2a in Neonatal Mouse Ovary.

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    Wang, Shufen; Liu, Jiali; Li, Xinqiang; Ji, Xiaowen; Zhang, Jianfang; Wang, Yue; Cui, Sheng

    2016-04-01

    The establishment of the primordial follicle pool is crucial for fertility in mammalian females, and the interruption of overall micro-RNA production byDicer1conditional knockout in the female reproductive system results in infertility. However, there are few reports about the functions of individual micro-RNA in regulating primordial follicle assembly. The present study aimed to investigate the function of miR-125b, which is conserved and preferentially expressed in mammalian ovary during primordial follicle assembly. Detection of miR-125b in the developing mouse ovaries by real-time PCR and in situ hybridization showed that it was highly expressed perinatally and specifically located in the ovarian somatic cells. MiR-125b overexpression blocked the process of primordial follicle assembly in cultured newborn mouse ovaries, while its knockdown promoted this process. Further studies showed that miR-125b regulated the activin/Smad2 signaling in neonatal mouse ovary by directly targeting the 3'-untranslated region of activin receptor type 2a (Acvr2a). Overexpression of miR-125b in neonatal mouse ovary suppressed theAcvr2aprotein level, attenuating activin/Smad2 signaling, while knockdown of miR-125b showed the opposite effects. In addition, recombinant human activin A (rh-ActA) down-regulated miR-125b in the neonatal mouse ovary. Overexpression of miR-125b attenuated the promoting effects of rh-ActA on primordial follicle assembly. Taken together, these data suggest that miR-125b blocks the process of primordial follicle assembly, and miR-125b may play this role by regulating the expression ofAcvr2ain the activin/Smad2 signaling pathway. © 2016 by the Society for the Study of Reproduction, Inc.

  15. Uterine activin receptor-like kinase 5 is crucial for blastocyst implantation and placental development

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    Peng, Jia; Monsivais, Diana; You, Ran; Zhong, Hua; Pangas, Stephanie A.; Matzuk, Martin M.

    2015-01-01

    Members of the transforming growth factor β (TGF-β) superfamily are key regulators in most developmental and physiological processes. However, the in vivo roles of TGF-β signaling in female reproduction remain uncertain. Activin receptor-like kinase 5 (ALK5) is the major type 1 receptor for the TGF-β subfamily. Absence of ALK5 leads to early embryonic lethality because of severe defects in vascular development. In this study, we conditionally ablated uterine ALK5 using progesterone receptor-cre mice to define the physiological roles of ALK5 in female reproduction. Despite normal ovarian functions and artificial decidualization in conditional knockout (cKO) mice, absence of uterine ALK5 resulted in substantially reduced female reproduction due to abnormalities observed at different stages of pregnancy, including implantation defects, disorganization of trophoblast cells, fewer uterine natural killer (uNK) cells, and impairment of spiral artery remodeling. In our microarray analysis, genes encoding proteins involved in cytokine–cytokine receptor interactions and NK cell-mediated cytotoxicity were down-regulated in cKO decidua compared with control decidua. Flow cytometry confirmed a 10-fold decrease in uNK cells in cKO versus control decidua. According to these data, we hypothesize that TGF-β acts on decidual cells via ALK5 to induce expression of other growth factors and cytokines, which are key regulators in luminal epithelium proliferation, trophoblast development, and uNK maturation during pregnancy. Our findings not only generate a mouse model to study TGF-β signaling in female reproduction but also shed light on the pathogenesis of many pregnancy complications in human, such as recurrent spontaneous abortion, preeclampsia, and intrauterine growth restriction. PMID:26305969

  16. Uterine activin receptor-like kinase 5 is crucial for blastocyst implantation and placental development.

    Science.gov (United States)

    Peng, Jia; Monsivais, Diana; You, Ran; Zhong, Hua; Pangas, Stephanie A; Matzuk, Martin M

    2015-09-08

    Members of the transforming growth factor β (TGF-β) superfamily are key regulators in most developmental and physiological processes. However, the in vivo roles of TGF-β signaling in female reproduction remain uncertain. Activin receptor-like kinase 5 (ALK5) is the major type 1 receptor for the TGF-β subfamily. Absence of ALK5 leads to early embryonic lethality because of severe defects in vascular development. In this study, we conditionally ablated uterine ALK5 using progesterone receptor-cre mice to define the physiological roles of ALK5 in female reproduction. Despite normal ovarian functions and artificial decidualization in conditional knockout (cKO) mice, absence of uterine ALK5 resulted in substantially reduced female reproduction due to abnormalities observed at different stages of pregnancy, including implantation defects, disorganization of trophoblast cells, fewer uterine natural killer (uNK) cells, and impairment of spiral artery remodeling. In our microarray analysis, genes encoding proteins involved in cytokine-cytokine receptor interactions and NK cell-mediated cytotoxicity were down-regulated in cKO decidua compared with control decidua. Flow cytometry confirmed a 10-fold decrease in uNK cells in cKO versus control decidua. According to these data, we hypothesize that TGF-β acts on decidual cells via ALK5 to induce expression of other growth factors and cytokines, which are key regulators in luminal epithelium proliferation, trophoblast development, and uNK maturation during pregnancy. Our findings not only generate a mouse model to study TGF-β signaling in female reproduction but also shed light on the pathogenesis of many pregnancy complications in human, such as recurrent spontaneous abortion, preeclampsia, and intrauterine growth restriction.

  17. Activin type IB receptor signaling in prostate cancer cells promotes lymph node metastasis in a xenograft model

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Masatoshi, E-mail: nomura@med.kyushu-u.ac.jp [Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Tanaka, Kimitaka; Wang, Lixiang; Goto, Yutaka; Mukasa, Chizu; Ashida, Kenji; Takayanagi, Ryoichi [Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer ActRIB signaling induces Snail and S100A4 expressions in prostate cancer cells. Black-Right-Pointing-Pointer The prostate cancer cell lines expressing an active form of ActRIB were established. Black-Right-Pointing-Pointer ActRIB signaling promotes EMT and lymph node metastasis in xenograft model. -- Abstract: Activin, a member of the transforming growth factor-{beta} family, has been known to be a growth and differentiating factor. Despite its pluripotent effects, the roles of activin signaling in prostate cancer pathogenesis are still unclear. In this study, we established several cell lines that express a constitutive active form of activin type IB receptor (ActRIBCA) in human prostate cancer cells, ALVA41 (ALVA-ActRIBCA). There was no apparent change in the proliferation of ALVA-ActRIBCA cells in vitro; however, their migratory ability was significantly enhanced. In a xenograft model, histological analysis revealed that the expression of Snail, a cell-adhesion-suppressing transcription factor, was dramatically increased in ALVA-ActRIBCA tumors, indicating epithelial mesenchymal transition (EMT). Finally, mice bearing ALVA-ActRIBCA cells developed multiple lymph node metastases. In this study, we demonstrated that ActRIBCA signaling can promote cell migration in prostate cancer cells via a network of signaling molecules that work together to trigger the process of EMT, and thereby aid in the aggressiveness and progression of prostate cancers.

  18. Inhibition of activin receptor type IIB increases strength and lifespan in myotubularin-deficient mice.

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    Lawlor, Michael W; Read, Benjamin P; Edelstein, Rachel; Yang, Nicole; Pierson, Christopher R; Stein, Matthew J; Wermer-Colan, Ariana; Buj-Bello, Anna; Lachey, Jennifer L; Seehra, Jasbir S; Beggs, Alan H

    2011-02-01

    X-linked myotubular myopathy (XLMTM) is a congenital disorder caused by deficiency of the lipid phosphatase, myotubularin. Patients with XLMTM often have severe perinatal weakness that requires mechanical ventilation to prevent death from respiratory failure. Muscle biopsy specimens from patients with XLMTM exhibit small myofibers with central nuclei and central aggregations of organelles in many cells. It was postulated that therapeutically increasing muscle fiber size would cause symptomatic improvement in myotubularin deficiency. Recent studies have elucidated an important role for the activin-receptor type IIB (ActRIIB) in regulation of muscle growth and have demonstrated that ActRIIB inhibition results in significant muscle hypertrophy. To evaluate whether promoting muscle hypertrophy can attenuate symptoms resulting from myotubularin deficiency, the effect of ActRIIB-mFC treatment was determined in myotubularin-deficient (Mtm1δ4) mice. Compared with wild-type mice, untreated Mtm1δ4 mice have decreased body weight, skeletal muscle hypotrophy, and reduced survival. Treatment of Mtm1δ4 mice with ActRIIB-mFC produced a 17% extension of lifespan, with transient increases in weight, forelimb grip strength, and myofiber size. Pathologic analysis of Mtm1δ4 mice during treatment revealed that ActRIIB-mFC produced marked hypertrophy restricted to type 2b myofibers, which suggests that oxidative fibers in Mtm1δ4 animals are incapable of a hypertrophic response in this setting. These results support ActRIIB-mFC as an effective treatment for the weakness observed in myotubularin deficiency. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  19. Endoglin-mediated suppression of prostate cancer invasion is regulated by activin and bone morphogenetic protein type II receptors.

    Directory of Open Access Journals (Sweden)

    Michael J Breen

    Full Text Available Mortality from prostate cancer (PCa is due to the formation of metastatic disease. Understanding how that process is regulated is therefore critical. We previously demonstrated that endoglin, a type III transforming growth factor β (TGFβ superfamily receptor, suppresses human PCa cell invasion and metastasis. Endoglin-mediated suppression of invasion was also shown by us to be dependent upon the type I TGFβ receptor, activin receptor-like kinase 2 (ALK2, and the downstream effector, Smad1. In this study we demonstrate for the first time that two type II TGFβ receptors are required for endoglin-mediated suppression of invasion: activin A receptor type IIA (ActRIIA and bone morphogenetic protein receptor type II (BMPRII. Downstream signaling through these receptors is predominantly mediated by Smad1. ActRIIA stimulates Smad1 activation in a kinase-dependent manner, and this is required for suppression of invasion. In contrast BMPRII regulates Smad1 in a biphasic manner, promoting Smad1 signaling through its kinase domain but suppressing it through its cytoplasmic tail. BMPRII's Smad1-regulatory effects are dependent upon its expression level. Further, its ability to suppress invasion is independent of either kinase function or tail domain. We demonstrate that ActRIIA and BMPRII physically interact, and that each also interacts with endoglin. The current findings demonstrate that both BMPRII and ActRIIA are necessary for endoglin-mediated suppression of human PCa cell invasion, that they have differential effects on Smad1 signaling, that they make separate contributions to regulation of invasion, and that they functionally and physically interact.

  20. Regulation of activin receptor-interacting protein 2 expression in mouse hepatoma Hepal-6 cells and its relationship with collagen type Ⅳ

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the regulation of activin receptor-interacting protein 2 (ARIP2) expression and its possible relationships with collagen type Ⅳ (collagen Ⅳ) in mouse hepatoma cell line Hepal-6 cells.METHODS: The ARIP2 mRNA expression kinetics in Hepal-6 cells was detected by RT-PCR, and its regulation factors were analyzed by treatment with signal transduction activators such as phorbol 12-myristate 13-acetate (PMA), forskolin and A23187. After pcDNA3-ARIP2 was transfected into Hepal-6 cells, the effects of ARIP2 overexpression on activin type Ⅱ receptor (ActRII)and collagen Ⅳ expression were evaluated.RESULTS: The expression levels of ARIP2 mRNA in Hapel-6 cells were elevated in time-dependent manner 12 h after treatment with activin A and endotoxin LPS, but not changed evidently in the early stage of stimulation (2 or 4 h). TheARIP2 mRNA expression was increased after stimulated with signal transduction activators such as PMA and forskolin in Hepal-6 cells, whereas decreased after treatment with A23187 (25.3% ± 5.7% vS 48.1% ± 3.6%, P < 0.01). ARIP2 overexpression could remarkably suppress the expression of ActRIIA mRNA in dose-dependent manner, but has no effect on ActRIIB in Hepal-6 cells induced by activin A. Furthermore, we have found that overexpression of ARIP2 could inhibit collagen Ⅳ mRNA and protein expressions induced by activin A in Hapel-6 cells.CONCLUSION: These findings suggest that ARIP2 expression can be influenced by various factors. ARIP2 may participate in the negative feedback regulation of signal transduction in the late stage by affecting the expression of ActRIIA and play an important role in regulation of development of liver fibrosis induced by activin.

  1. Differential expression of mRNAs encoding the putative inhibin co-receptor (betaglycan) and activin type-I and type-II receptors in preovulatory and prehierarchical follicles of the laying hen ovary.

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    Lovell, T M; Knight, P G; Gladwell, R T

    2006-02-01

    Ovarian follicle development is primarily regulated by an interplay between the pituitary gonadotrophins, LH and FSH, and ovary-derived steroids. Increasing evidence implicates regulatory roles of transforming growth factor-beta (TGFbeta) superfamily members, including inhibins and activins. The aim of this study was to identify the expression of mRNAs encoding key receptors of the inhibin/activin system in ovarian follicles ranging from 4 mm in diameter to the dominant F1 follicle (approximately 40 mm). Ovaries were collected (n = 16) from mid-sequence hens maintained on a long-day photoschedule (16 h of light:8 h of darkness). All follicles removed were dissected into individual granulosa and thecal layers. RNA was extracted and cDNA synthesized. Real-time quantitative PCR was used to quantify the expression of mRNA encoding betaglycan, activin receptor (ActR) subtypes (type-I, -IIA and -IIB) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH); receptor expression data were normalized to GAPDH expression. Detectable levels of ActRI, -IIA and -IIB and the inhibin co-receptor (betaglycan) expression were found in all granulosa and thecal layers analysed. Granulosa ActRI mRNA peaked (P II activin receptors and betaglycan on granulosa and thecal cells are consistent with a local auto/paracrine role of inhibins and activins in modulating ovarian follicle development, selection and progression in the domestic fowl.

  2. Molecular characterization of Activin Receptor Type IIA and its expression during gonadal maturation and growth stages in rohu carp.

    Science.gov (United States)

    Patnaik, Siddhi; Mohanty, Mausumee; Bit, Amrita; Sahoo, Lakshman; Das, Sachidananda; Jayasankar, Pallipuram; Das, Paramananda

    2017-01-01

    Activin receptor type IIA (ActRIIA), a transmembrane serine/threonine kinase receptor is an important regulator of physiological traits, viz., reproduction and body growth in vertebrates including teleosts. However, existing knowledge of its role in regulating fish physiology is limited. To address this, we have cloned and characterized the ActRIIA cDNA of Labeo rohita (rohu), an economically important fish species of the Indian subcontinent. Comparative expression profiling of the receptor gene at various reproductive and growth stages supports to its role in promoting oocyte maturation, spermatogenesis and skeletal muscle development via interaction with multiple ligands of transforming growth factor-β (TGF-β) family. The full-length cDNA of rohu ActRIIA was found to be of 1587bp length encoding 528 amino acids. The three-dimensional structure of the intracellular kinase domain of rohu ActRIIA has also been predicted. Phylogenetic relationship studies showed that the gene is evolutionarily conserved across the vertebrate lineage implicating that the functioning of the receptor is more or less similar in vertebrates. Taken together, these findings could be an initial step towards the use of ActRIIA as a potential candidate gene marker for understanding the complex regulatory mechanism of fish reproduction and growth.

  3. Novel Protein Interactions with Endoglin and Activin Receptor-like Kinase 1: Potential Role in Vascular Networks*

    Science.gov (United States)

    Xu, Guoxiong; Barrios-Rodiles, Miriam; Jerkic, Mirjana; Turinsky, Andrei L.; Nadon, Robert; Vera, Sonia; Voulgaraki, Despina; Wrana, Jeffrey L.; Toporsian, Mourad; Letarte, Michelle

    2014-01-01

    Endoglin and activin receptor-like kinase 1 are specialized transforming growth factor-beta (TGF-β) superfamily receptors, primarily expressed in endothelial cells. Mutations in the corresponding ENG or ACVRL1 genes lead to hereditary hemorrhagic telangiectasia (HHT1 and HHT2 respectively). To discover proteins interacting with endoglin, ACVRL1 and TGF-β receptor type 2 and involved in TGF-β signaling, we applied LUMIER, a high-throughput mammalian interactome mapping technology. Using stringent criteria, we identified 181 novel unique and shared interactions with ACVRL1, TGF-β receptor type 2, and endoglin, defining potential novel important vascular networks. In particular, the regulatory subunit B-beta of the protein phosphatase PP2A (PPP2R2B) interacted with all three receptors. Interestingly, the PPP2R2B gene lies in an interval in linkage disequilibrium with HHT3, for which the gene remains unidentified. We show that PPP2R2B protein interacts with the ACVRL1/TGFBR2/endoglin complex and recruits PP2A to nitric oxide synthase 3 (NOS3). Endoglin overexpression in endothelial cells inhibits the association of PPP2R2B with NOS3, whereas endoglin-deficient cells show enhanced PP2A-NOS3 interaction and lower levels of endogenous NOS3 Serine 1177 phosphorylation. Our data suggest that endoglin regulates NOS3 activation status by regulating PPP2R2B access to NOS3, and that PPP2R2B might be the HHT3 gene. Furthermore, endoglin and ACVRL1 contribute to several novel networks, including TGF-β dependent and independent ones, critical for vascular function and potentially defective in HHT. PMID:24319055

  4. Modified activin receptor IIB ligand trap mitigates ineffective erythropoiesis and disease complications in murine β-thalassemia.

    Science.gov (United States)

    Suragani, Rajasekhar N V S; Cawley, Sharon M; Li, Robert; Wallner, Samantha; Alexander, Mark J; Mulivor, Aaron W; Gardenghi, Sara; Rivella, Stefano; Grinberg, Asya V; Pearsall, R Scott; Kumar, Ravindra

    2014-06-19

    In β-thalassemia, unequal production of α- and β-globin chains in erythroid precursors causes apoptosis and inhibition of late-stage erythroid differentiation, leading to anemia, ineffective erythropoiesis (IE), and dysregulated iron homeostasis. Here we used a murine model of β-thalassemia intermedia (Hbb(th1/th1) mice) to investigate effects of a modified activin receptor type IIB (ActRIIB) ligand trap (RAP-536) that inhibits Smad2/3 signaling. In Hbb(th1/th1) mice, treatment with RAP-536 reduced overactivation of Smad2/3 in splenic erythroid precursors. In addition, treatment of Hbb(th1/th1) mice with RAP-536 reduced α-globin aggregates in peripheral red cells, decreased the elevated reactive oxygen species present in erythroid precursors and peripheral red cells, and alleviated anemia by promoting differentiation of late-stage erythroid precursors and reducing hemolysis. Notably, RAP-536 treatment mitigated disease complications of IE, including iron overload, splenomegaly, and bone pathology, while reducing erythropoietin levels, improving erythrocyte morphology, and extending erythrocyte life span. These results implicate signaling by the transforming growth factor-β superfamily in late-stage erythropoiesis and reveal potential of a modified ActRIIB ligand trap as a novel therapeutic agent for thalassemia syndrome and other red cell disorders characterized by IE.

  5. Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

    Institute of Scientific and Technical Information of China (English)

    Douglas J DiGirolamo; Vandana Singhal; Xiaoli Chang; Se-Jin Lee; Emily L Germain-Lee

    2015-01-01

    Osteogenesis imperfecta (OI) comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI, many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B (ACVR2B) in a mouse model of type III OI (oim). Treatment of 12-week-old oim mice with ACVR2B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy, wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system.

  6. Blockade of the activin receptor IIb activates functional brown adipogenesis and thermogenesis by inducing mitochondrial oxidative metabolism.

    Science.gov (United States)

    Fournier, Brigitte; Murray, Ben; Gutzwiller, Sabine; Marcaletti, Stefan; Marcellin, David; Bergling, Sebastian; Brachat, Sophie; Persohn, Elke; Pierrel, Eliane; Bombard, Florian; Hatakeyama, Shinji; Trendelenburg, Anne-Ulrike; Morvan, Frederic; Richardson, Brian; Glass, David J; Lach-Trifilieff, Estelle; Feige, Jerome N

    2012-07-01

    Brown adipose tissue (BAT) is a key tissue for energy expenditure via fat and glucose oxidation for thermogenesis. In this study, we demonstrate that the myostatin/activin receptor IIB (ActRIIB) pathway, which serves as an important negative regulator of muscle growth, is also a negative regulator of brown adipocyte differentiation. In parallel to the anticipated hypertrophy of skeletal muscle, the pharmacological inhibition of ActRIIB in mice, using a neutralizing antibody, increases the amount of BAT without directly affecting white adipose tissue. Mechanistically, inhibition of ActRIIB inhibits Smad3 signaling and activates the expression of myoglobin and PGC-1 coregulators in brown adipocytes. Consequently, ActRIIB blockade in brown adipose tissue enhances mitochondrial function and uncoupled respiration, translating into beneficial functional consequences, including enhanced cold tolerance and increased energy expenditure. Importantly, ActRIIB inhibition enhanced energy expenditure only at ambient temperature or in the cold and not at thermoneutrality, where nonshivering thermogenesis is minimal, strongly suggesting that brown fat activation plays a prominent role in the metabolic actions of ActRIIB inhibition.

  7. Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

    Science.gov (United States)

    DiGirolamo, Douglas J.; Singhal, Vandana; Chang, Xiaoli; Lee, Se-Jin; Germain-Lee, Emily L.

    2015-01-01

    Osteogenesis imperfecta (OI) comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI, many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B (ACVR2B) in a mouse model of type III OI (oim). Treatment of 12-week-old oim mice with ACVR2B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy, wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system. PMID:26161291

  8. Heterozygous disruption of activin receptor-like kinase 1 is associated with increased arterial pressure in mice

    Directory of Open Access Journals (Sweden)

    María González-Núñez

    2015-11-01

    Full Text Available The activin receptor-like kinase 1 (ALK-1 is a type I cell-surface receptor for the transforming growth factor-β (TGF-β family of proteins. Hypertension is related to TGF-β1, because increased TGF-β1 expression is correlated with an elevation in arterial pressure (AP and TGF-β expression is upregulated by the renin-angiotensin-aldosterone system. The purpose of this study was to assess the role of ALK-1 in regulation of AP using Alk1 haploinsufficient mice (Alk1+/−. We observed that systolic and diastolic AP were significantly higher in Alk1+/− than in Alk1+/+ mice, and all functional and structural cardiac parameters (echocardiography and electrocardiography were similar in both groups. Alk1+/− mice showed alterations in the circadian rhythm of AP, with higher AP than Alk1+/+ mice during most of the light period. Higher AP in Alk1+/− mice is not a result of a reduction in the NO-dependent vasodilator response or of overactivation of the peripheral renin-angiotensin system. However, intracerebroventricular administration of losartan had a hypotensive effect in Alk1+/− and not in Alk1+/+ mice. Alk1+/− mice showed a greater hypotensive response to the β-adrenergic antagonist atenolol and higher concentrations of epinephrine and norepinephrine in plasma than Alk1+/+ mice. The number of brain cholinergic neurons in the anterior basal forebrain was reduced in Alk1+/− mice. Thus, we concluded that the ALK-1 receptor is involved in the control of AP, and the high AP of Alk1+/− mice is explained mainly by the sympathetic overactivation shown by these animals, which is probably related to the decreased number of cholinergic neurons.

  9. BDNF Reduces Toxic Extrasynaptic NMDA Receptor Signaling via Synaptic NMDA Receptors and Nuclear-Calcium-Induced Transcription of inhba/Activin A

    Directory of Open Access Journals (Sweden)

    David Lau

    2015-08-01

    Full Text Available The health of neurons is critically dependent on the relative signaling intensities of survival-promoting synaptic and death-inducing extrasynaptic NMDA receptors. Here, we show that BDNF is a regulator of this balance and promotes neuroprotection by reducing toxic NMDA receptor signaling. BDNF acts by initiating synaptic NMDA-receptor/nuclear-calcium-driven adaptogenomics, leading to increased expression of inhibin β-A (inhba. Inhibin β-A (its homodimer is known as activin A in turn reduces neurotoxic extrasynaptic NMDA-receptor-mediated calcium influx, thereby shielding neurons against mitochondrial dysfunction, a major cause of excitotoxicity. Thus, BDNF induces acquired neuroprotection by enhancing synaptic activity and lowering extrasynaptic NMDA receptor death signaling through a nuclear calcium-inhibin β-A pathway. This process, which confers protection against ischemic brain damage in a mouse stroke model, may be compromised in Huntington’s disease, Alzheimer’s disease, or aging-related neurodegenerative conditions that are associated with reduced BDNF levels and/or enhanced extrasynaptic NMDA receptor signaling.

  10. Activin receptor-like kinase 7 suppresses lipolysis to accumulate fat in obesity through downregulation of peroxisome proliferator-activated receptor γ and C/EBPα.

    Science.gov (United States)

    Yogosawa, Satomi; Mizutani, Shin; Ogawa, Yoshihiro; Izumi, Tetsuro

    2013-01-01

    We previously identified a quantitative trait locus for adiposity, non-insulin-dependent diabetes 5 (Nidd5), on mouse chromosome 2. In the current study, we identified the actual genetic alteration at Nidd5 as a nonsense mutation of the Acvr1c gene encoding activin receptor-like kinase 7 (ALK7), one of the type I transforming growth factor-β receptors, which results in a COOH-terminal deletion of the kinase domain. We further showed that the ALK7 dysfunction causes increased lipolysis in adipocytes and leads to decreased fat accumulation. Conversely, ALK7 activation inhibits lipolysis by suppressing the expression of adipose lipases. ALK7 and activated Smads repress those lipases by downregulating peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein (C/EBP) α. Although PPARγ and C/EBPα act as adipogenic transcription factors during adipocyte differentiation, they are lipolytic in sum in differentiated adipocytes and are downregulated by ALK7 in obesity to accumulate fat. Under the obese state, ALK7 deficiency improves glucose tolerance and insulin sensitivity by preferentially increasing fat combustion in mice. These findings have uncovered a net lipolytic function of PPARγ and C/EBPα in differentiated adipocytes and point to the ALK7-signaling pathway that is activated in obesity as a potential target of medical intervention.

  11. Activin Receptor-Like Kinase 7 Suppresses Lipolysis to Accumulate Fat in Obesity Through Downregulation of Peroxisome Proliferator–Activated Receptor γ and C/EBPα

    Science.gov (United States)

    Yogosawa, Satomi; Mizutani, Shin; Ogawa, Yoshihiro; Izumi, Tetsuro

    2013-01-01

    We previously identified a quantitative trait locus for adiposity, non-insulin-dependent diabetes 5 (Nidd5), on mouse chromosome 2. In the current study, we identified the actual genetic alteration at Nidd5 as a nonsense mutation of the Acvr1c gene encoding activin receptor-like kinase 7 (ALK7), one of the type I transforming growth factor-β receptors, which results in a COOH-terminal deletion of the kinase domain. We further showed that the ALK7 dysfunction causes increased lipolysis in adipocytes and leads to decreased fat accumulation. Conversely, ALK7 activation inhibits lipolysis by suppressing the expression of adipose lipases. ALK7 and activated Smads repress those lipases by downregulating peroxisome proliferator–activated receptor γ (PPARγ) and CCAAT/enhancer binding protein (C/EBP) α. Although PPARγ and C/EBPα act as adipogenic transcription factors during adipocyte differentiation, they are lipolytic in sum in differentiated adipocytes and are downregulated by ALK7 in obesity to accumulate fat. Under the obese state, ALK7 deficiency improves glucose tolerance and insulin sensitivity by preferentially increasing fat combustion in mice. These findings have uncovered a net lipolytic function of PPARγ and C/EBPα in differentiated adipocytes and point to the ALK7-signaling pathway that is activated in obesity as a potential target of medical intervention. PMID:22933117

  12. Gonadotropin-induced changes in oviducal mRNA expression levels of sex steroid hormone receptors and activin-related signaling factors in the alligator

    Science.gov (United States)

    Moore, Brandon C.; Forouhar, Sara; Kohno, Satomi; Botteri, Nicole L.; Hamlin, Heather J.; Guillette, Louis J.

    2011-01-01

    Oviducts respond to hormonal cues from ovaries with tissue proliferation and differentiation in preparation of transporting and fostering gametes. These responses produce oviducal microenvironments conducive to reproductive success. Here we investigated changes in circulating plasma sex steroid hormones concentrations and ovarian and oviducal mRNA expression to an in vivo gonadotropin (FSH) challenge in sexually immature, five-month-old alligators. Further, we investigated differences in these observed responses between alligators hatched from eggs collected at a heavily-polluted (Lake Apopka, FL) and minimally-polluted (Lake Woodruff, FL) site. In oviducts, we measured mRNA expression of estrogen, progesterone, and androgen receptors and also beta A and B subunits which homo- or heterodimerize to produce the transforming growth factor activin. In comparison, minimal inhibin alpha subunit mRNA expression suggests that these oviducts produce a primarily activin-dominated signaling milieu. Ovaries responded to a five-day FSH challenge with increased expression of steroidogenic enzyme mRNA which was concomitant with increased circulating sex steroid hormone concentrations. Oviducts in the FSH-challenged Lake Woodruff alligators increased mRNA expression of progesterone and androgen receptors, proliferating cell nuclear antigen, and the activin signaling antagonist follistatin. In contrast, Lake Apopka alligators displayed a diminished increase in ovarian CYP19A1 aromatase expression and no increase in oviducal AR expression, as compared to those observed in Lake Woodruff alligators. These results demonstrate that five-month-old female alligators display an endocrine-responsive ovarian-oviducal axis and environmental pollution exposure may alter these physiological responses. PMID:22154572

  13. Sotatercept, a soluble activin receptor type 2A IgG-Fc fusion protein for the treatment of anemia and bone loss.

    Science.gov (United States)

    Raje, Noopur; Vallet, Sonia

    2010-10-01

    Sotatercept (ACE-011), under development by Acceleron Pharma Inc in collaboration with Celgene Corp, is a chimeric protein containing the extracellular domain of the activin receptor 2A (ACVR2A) fused to the Fc domain of human IgG1. Sotatercept contains the binding site of ACVR2A and interferes with downstream signaling cascades, in particular the SMAD pathway, by sequestering activin. The murine counterpart of sotatercept, referred to as RAP-011, has been extensively evaluated in preclinical studies, in particular in models of cancer- and osteoporosis-related bone loss, and the developing companies envisage that sotatercept may also have potential for the treatment of cancer and cancer-related bone loss. In a phase I clinical trial in postmenopausal females, sotatercept increased hematocrit levels, and, in a phase II trial in patients with multiple myeloma, a trend toward improvement in osteolytic lesions as well as antitumor activity was observed. At the time of publication, phase II trials in patients with anemia were ongoing. Future clinical development will rely on an evaluation of the benefits and complications of sotatercept administration, focusing in particular on suppression of ovarian function and increases in hematocrit levels without a consequent risk of hypertension and thrombosis.

  14. Activin suppresses LPS-induced Toll-like receptor, cytokine and inducible nitric oxide synthase expression in normal human melanocytes by inhibiting NF-κB and MAPK pathway activation.

    Science.gov (United States)

    Kim, Young Il; Park, Seung-Won; Kang, In Jung; Shin, Min Kyung; Lee, Mu-Hyoung

    2015-10-01

    Activins are dimeric growth and differentiation factors that belong to the transforming growth factor (TGF)-β superfamily of structurally related signaling proteins. In the present study, we examined the mechanisms through which activin regulates the lipopolysaccharide (LPS)-induced transcription of Toll-like receptors (TLRs), cytokines and inducible nitric oxide synthase (iNOS) in human melanocytes, as well as the involvement of nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling. Cell proliferation was analyzed by cell viability assay, mRNA expression was detected by RT-qPCR, and protein expression was measured by western blot analysis. LPS increased the mRNA expression of TLRs (TLR1-10) and cytokines [interleukin (IL)-1β, IL-6, IL-8 and TNF-α], as well as the mRNA and protein expression of iNOS. Activin decreased the LPS-induced TLR and cytokine mRNA expression, as well as the LPS-induced iNOS mRNA and protein expression. In addition, activin suppressed NF-κB p65 activation and blocked inhibitor of NF-κB (IκBα) degradation in LPS-stimulated melanocytes, and reduced LPS-induced p38 MAPK and MEK/ERK activation. On the whole, our results demonstrated that activin inhibited TLR and cytokine expression in LPS-activated normal human melanocytes and suppressed LPS-induced iNOS gene expression. Moreover, the anti-inflammatory effects of activin were shown to be mediated through the suppression of NF-κB and MAPK signaling, resulting in reduced TLR and iNOS expression, and in the inhibition of inflammatory cytokine expression.

  15. Endoglin and activin receptor-like kinase 1 heterozygous mice have a distinct pulmonary and hepatic angiogenic profile and response to anti-VEGF treatment.

    Science.gov (United States)

    Ardelean, Daniela S; Jerkic, Mirjana; Yin, Melissa; Peter, Madonna; Ngan, Bo; Kerbel, Robert S; Foster, F Stuart; Letarte, Michelle

    2014-01-01

    Hereditary hemorrhagic telangiectasia (HHT) is a vascular dysplasia associated with dysregulated angiogenesis and arteriovascular malformations. The disease is caused by mutations in endoglin (ENG; HHT1) or activin receptor-like kinase 1 (ALK1; HHT2) genes, coding for transforming growth factor β (TGF-β) superfamily receptors. Vascular endothelial growth factor (VEGF) has been implicated in HHT and beneficial effects of anti-VEGF treatment were recently reported in HHT patients. To investigate the systemic angiogenic phenotype of Endoglin and Alk1 mutant mice and their response to anti-VEGF therapy, we assessed microvessel density (MVD) in multiple organs after treatment with an antibody to mouse VEGF or vehicle. Lungs were the only organ showing an angiogenic defect, with reduced peripheral MVD and secondary right ventricular hypertrophy (RVH), yet distinctly associated with a fourfold increase in thrombospondin-1 (TSP-1) in Eng (+/-) versus a rise in angiopoietin-2 (Ang-2) in Alk1 (+/-) mice. Anti-VEGF treatment did reduce lung VEGF levels but interestingly, led to an increase in peripheral pulmonary MVD and attenuation of RVH; it also normalized TSP-1 and Ang-2 expression. Hepatic MVD, unaffected in mutant mice, was reduced by anti-VEGF therapy in heterozygous and wild type mice, indicating a liver-specific effect of treatment. Contrast-enhanced micro-ultrasound demonstrated a reduction in hepatic microvascular perfusion after anti-VEGF treatment only in Eng (+/-) mice. Our findings indicate that the mechanisms responsible for the angiogenic imbalance and the response to anti-VEGF therapy differ between Eng and Alk1 heterozygous mice and raise the need for systemic monitoring of anti-angiogenic therapy effects in HHT patients.

  16. Activin B is produced early in antral follicular development and suppresses thecal androgen production

    Science.gov (United States)

    Young, J M; Henderson, S; Souza, C; Ludlow, H; Groome, N; McNeilly, A S

    2012-01-01

    Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s). PMID:22450673

  17. Complete reversal of muscle wasting in experimental cancer cachexia: Additive effects of activin type II receptor inhibition and β-2 agonist.

    Science.gov (United States)

    Toledo, Míriam; Busquets, Sílvia; Penna, Fabio; Zhou, Xiaolan; Marmonti, Enrica; Betancourt, Angelica; Massa, David; López-Soriano, Francisco J; Han, H Q; Argilés, Josep M

    2016-04-15

    Formoterol is a highly potent β2-adrenoceptor-selective agonist, which is a muscle growth promoter in many animal species. Myostatin/activin inhibition reverses skeletal muscle loss and prolongs survival of tumor-bearing animals. The aim of this investigation was to evaluate the effects of a combination of the soluble myostatin receptor ActRIIB (sActRIIB) and the β2-agonist formoterol in the cachectic Lewis lung carcinoma model. The combination of formoterol and sActRIIB was extremely effective in reversing muscle wasting associated with experimental cancer cachexia in mice. Muscle weights from tumor-bearing animals were completely recovered following treatment and this was also reflected in the measured grip strength. This combination increased food intake in both control and tumor-bearing animals. The double treatment also prolonged survival significantly without affecting the weight and growth of the primary tumor. In addition, it significantly reduced the number of metastasis. Concerning the mechanisms for the preservation of muscle mass during cachexia, the effects of formoterol and sActRIIB seemed to be additive, since formoterol reduced the rate of protein degradation (as measured in vitro as tyrosine release, using incubated isolated individual muscles) while sActRIIB only affected protein synthesis (as measured in vivo using tritiated phenylalanine). Formoterol also increased the rate of protein synthesis and this seemed to be favored by the presence of sActRIIB. Combining formoterol and sActRIIB seemed to be a very promising treatment for experimental cancer cachexia. Further studies in human patients are necessary and may lead to a highly effective treatment option for muscle wasting associated with cancer.

  18. Activin is a potent growth suppressor of epithelial ovarian cancer cells.

    Science.gov (United States)

    Ramachandran, Anassuya; Marshall, Elaine S; Love, Donald R; Baguley, Bruce C; Shelling, Andrew N

    2009-11-28

    Although activin is a major cytokine produced by the ovary, its role in epithelial ovarian cancer is poorly defined. Here, we demonstrate a novel role for activin as a growth inhibitor of some (8/16) epithelial ovarian cancer cell lines. Unresponsive cell lines displayed transcriptional downregulation of the activin receptors ACTRIIA and ACTRIB, suggesting resistance to activin signalling. In response to activin, growth inhibited cell lines demonstrated activation of the canonical SMAD2/3/4, transcriptional induction of the CDK inhibitor p15INK4B, suppression of C-MYC levels and a G1 phase cell cycle arrest. Thus, activin is a potent inhibitor of proliferation of some epithelial ovarian cancer cell lines and its role in the pathogenesis of this disease needs to be re-evaluated.

  19. Characterization of the human Activin-A receptor type II-like kinase 1 (ACVRL1 promoter and its regulation by Sp1

    Directory of Open Access Journals (Sweden)

    Botella Luisa M

    2010-06-01

    Full Text Available Abstract Background Activin receptor-like kinase 1 (ALK1 is a Transforming Growth Factor-β (TGF-β receptor type I, mainly expressed in endothelial cells that plays a pivotal role in vascular remodelling and angiogenesis. Mutations in the ALK1 gene (ACVRL1 give rise to Hereditary Haemorrhagic Telangiectasia, a dominant autosomal vascular dysplasia caused by a haploinsufficiency mechanism. In spite of its patho-physiological relevance, little is known about the transcriptional regulation of ACVRL1. Here, we have studied the different origins of ACVRL1 transcription, we have analyzed in silico its 5'-proximal promoter sequence and we have characterized the role of Sp1 in the transcriptional regulation of ACVRL1. Results We have performed a 5'Rapid Amplification of cDNA Ends (5'RACE of ACVRL1 transcripts, finding two new transcriptional origins, upstream of the one previously described, that give rise to a new exon undiscovered to date. The 5'-proximal promoter region of ACVRL1 (-1,035/+210 was analyzed in silico, finding that it lacks TATA/CAAT boxes, but contains a remarkably high number of GC-rich Sp1 consensus sites. In cells lacking Sp1, ACVRL1 promoter reporters did not present any significant transcriptional activity, whereas increasing concentrations of Sp1 triggered a dose-dependent stimulation of its transcription. Moreover, silencing Sp1 in HEK293T cells resulted in a marked decrease of ACVRL1 transcriptional activity. Chromatin immunoprecipitation assays demonstrated multiple Sp1 binding sites along the proximal promoter region of ACVRL1 in endothelial cells. Furthermore, demethylation of CpG islands, led to an increase in ACVRL1 transcription, whereas in vitro hypermethylation resulted in the abolishment of Sp1-dependent transcriptional activation of ACVRL1. Conclusions Our results describe two new transcriptional start sites in ACVRL1 gene, and indicate that Sp1 is a key regulator of ACVRL1 transcription, providing new insights into

  20. Acute Modulation of Synaptic Plasticity of Pyramidal Neurons by Activin in Adult Hippocampus

    Directory of Open Access Journals (Sweden)

    Yoshitaka eHasegawa

    2014-06-01

    Full Text Available Activin A is known as a neuroprotective factor produced upon acute excitotoxic injury of the hippocampus (in pathological states. We attempt to reveal the role of activin as a neuromodulator in the adult male hippocampus under physiological conditions (in healthy states, which remains largely unknown. We showed endogenous/basal expression of activin in the hippocampal neurons. Localization of activin receptors in dendritic spines (= postsynapses was demonstrated by immunoelectron microscopy. The incubation of hippocampal acute slices with activin A (10 ng/mL, 0.4 nM for 2 h altered the density and morphology of spines in CA1 pyramidal neurons. The total spine density increased by 1.2-fold upon activin treatments. Activin selectively increased the density of large-head spines, without affecting middle-head and small-head spines. Blocking of Erk/MAPK, PKA or PKC prevented the activin-induced spinogenesis by reducing the density of large-head spines, independent of Smad-induced gene transcription which usually takes more than several hours. Incubation of acute slices with activin for 2 h induced the moderate early long-term potentiation (moderate LTP upon weak theta burst stimuli. This moderate LTP induction was blocked by follistatin, MAPK inhibitor (PD98059 and inhibitor of NR2B subunit of NMDA receptors (Ro25-6981. It should be noted that the weak theta burst stimuli alone cannot induce moderate LTP. These results suggest that MAPK-induced phosphorylation of NMDA receptors (including NR2B may play an important role for activin-induced moderate LTP. Taken together, the current results reveal interesting physiological roles of endogenous activin as a synaptic modulator in the adult hippocampus.

  1. 激活素受体相互作用蛋白1及2在小鼠巨噬细胞中的表达%Expression of activin receptor-interacting proteins 1, 2 in mouse macrophages

    Institute of Scientific and Technical Information of China (English)

    崔雪玲; 葛敬岩; 李晨光; 孙洋; 牛立慢; 刘海岩; 柳忠辉; 王轶楠

    2012-01-01

    Objective To investigate the expression and role of activin receptor-interacting proteins 1, 2 (ARIP1, 2) in mouse macrophages. Methods The expression of ARIP1, 2 was determined by immunocytochemical staining. RAW264. 7 cells were co-transfected with plasmids CAGA-lux and CMV-gal, plus plasmids pcDNA3-ARIPl, pcDNA3-ARIP2 or empty plasmid pcDNA3, respectively, then stimulated with activin A, and determined for transcription activity of report gene. The expression of ActR II A mRNA was determined by RT-PCR. Results Immunocytochemical staining proved that ARIP1,2 were expressed in RAW264. 7 cells. The overexpressions of ARIP1, 2 inhibited the transcription of specific gene induced by activin A. The overexpression of ARIP2 inhibited, while that of ARIP1 showed no significant effect on the expression of ActR II A mRNA in RAW264. 7 cells. Conclusion ARIP1, 2 were coexpressed in mouse macrophages, which down-regulated the signal transduction of activin by different action modes.%目的 探讨激活素受体相互作用蛋白(Activin receptor-interacting protein,ARIP)1及2(ARIP1,2)在小鼠巨噬细胞RAW264.7中的表达及作用.方法 采用免疫细胞化学染色法检测RAW264.7细胞中ARIP1,2的表达;将质粒CAGA-lux、CMV-gal分别与表达质粒pcDNA3-ARIP1、pcDNA3-ARIP2或空质粒pcDNA3共转染RAW264.7细胞,应用激活素A刺激,检测细胞内报告基因转录荧光素酶的活性;实时定量RT-PCR检测ActRⅡA mRNA的表达.结果 免疫细胞化学染色结果显示,小鼠巨噬细胞系RAW264.7细胞表达ARIP1,2;RAW264.7细胞过表达ARIP1,2均能抑制Activin A诱导的特异基因转录;过表达ARIP2可抑制RAW264.7细胞ActRⅡA mRNA的表达,而过表达ARIP1对ActRⅡA mRNA的表达无明显影响.结论 ARIP1,2在小鼠巨噬细胞中共表达,并具有下调激活素信号传导的作用,但其作用方式不同.

  2. Activin tunes GABAergic neurotransmission and modulates anxiety-like behavior.

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    Zheng, F; Adelsberger, H; Müller, M R; Fritschy, J-M; Werner, S; Alzheimer, C

    2009-03-01

    Activin, a member of the transforming growth factor-beta superfamily, affords neuroprotection in acute brain injury, but its physiological functions in normal adult brain are largely unknown. Using transgenic (tg) mice expressing a dominant-negative activin receptor mutant under the control of the CaMKIIalpha promoter in forebrain neurons, we identified activin as a key regulator of gamma-aminobutyric acid (GABA)ergic synapses and anxiety-like behavior. In the open field, wild-type (wt) and tg mice did not differ in spontaneous locomotion and exploration behavior. However, tg mice visited inner fields significantly more often than wt mice. In the light-dark exploration test, tg mice made more exits, spent significantly more time on a well-lit elevated bar and went farther away from the dark box as compared to wt mice. In addition, the anxiolytic effect of diazepam was abrogated in tg mice. Thus the disruption of activin receptor signaling produced a low-anxiety phenotype that failed to respond to benzodiazepines. In whole-cell recordings from hippocampal pyramidal cells, enhanced spontaneous GABA release, increased GABA tonus, reduced benzodiazepine sensitivity and augmented GABA(B) receptor function emerged as likely substrates of the low-anxiety phenotype. These data provide strong evidence that activin influences pre- and postsynaptic components of GABAergic synapses in a highly synergistic fashion. Given the crucial role of GABAergic neurotransmission in emotional states, anxiety and depression, dysfunctions of activin receptor signaling could be involved in affective disorders: and drugs affecting this pathway might show promise for psychopharmacological treatment.

  3. Activin Receptor-Like Kinase Receptors ALK5 and ALK1 Are Both Required for TGFβ-Induced Chondrogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells

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    de Kroon, Laurie M. G.; Narcisi, Roberto; Blaney Davidson, Esmeralda N.; Cleary, Mairéad A.; van Beuningen, Henk M.; Koevoet, Wendy J. L. M.; van Osch, Gerjo J. V. M.; van der Kraan, Peter M.

    2015-01-01

    Introduction Bone marrow-derived mesenchymal stem cells (BMSCs) are promising for cartilage regeneration because BMSCs can differentiate into cartilage tissue-producing chondrocytes. Transforming Growth Factor β (TGFβ) is crucial for inducing chondrogenic differentiation of BMSCs and is known to signal via Activin receptor-Like Kinase (ALK) receptors ALK5 and ALK1. Since the specific role of these two TGFβ receptors in chondrogenesis is unknown, we investigated whether ALK5 and ALK1 are expressed in BMSCs and whether both receptors are required for chondrogenic differentiation of BMSCs. Materials & Methods ALK5 and ALK1 gene expression in human BMSCs was determined with RT-qPCR. To induce chondrogenesis, human BMSCs were pellet-cultured in serum-free chondrogenic medium containing TGFβ1. Chondrogenesis was evaluated by aggrecan and collagen type IIα1 RT-qPCR analysis, and histological stainings of proteoglycans and collagen type II. To overexpress constitutively active (ca) receptors, BMSCs were transduced either with caALK5 or caALK1. Expression of ALK5 and ALK1 was downregulated by transducing BMSCs with shRNA against ALK5 or ALK1. Results ALK5 and ALK1 were expressed in in vitro-expanded as well as in pellet-cultured BMSCs from five donors, but mRNA levels of both TGFβ receptors did not clearly associate with chondrogenic induction. TGFβ increased ALK5 and decreased ALK1 gene expression in chondrogenically differentiating BMSC pellets. Neither caALK5 nor caALK1 overexpression induced cartilage matrix formation as efficient as that induced by TGFβ. Moreover, short hairpin-mediated downregulation of either ALK5 or ALK1 resulted in a strong inhibition of TGFβ-induced chondrogenesis. Conclusion ALK5 as well as ALK1 are required for TGFβ-induced chondrogenic differentiation of BMSCs, and TGFβ not only directly induces chondrogenesis, but also modulates ALK5 and ALK1 receptor signaling in BMSCs. These results imply that optimizing cartilage formation by

  4. Regulation of FSHβ induction in LβT2 cells by BMP2 and an Activin A/BMP2 chimera, AB215.

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    Jung, Jae Woo; Ahn, Chihoon; Shim, Sun Young; Gray, Peter C; Kwiatkowski, Witek; Choe, Senyon

    2014-10-01

    Activins and bone morphogenetic proteins (BMPs) share activin type 2 signaling receptors but utilize different type 1 receptors and Smads. We designed AB215, a potent BMP2-like Activin A/BMP2 chimera incorporating the high-affinity type 2 receptor-binding epitope of Activin A. In this study, we compare the signaling properties of AB215 and BMP2 in HEK293T cells and gonadotroph LβT2 cells in which Activin A and BMP2 synergistically induce FSHβ. In HEK293T cells, AB215 is more potent than BMP2 and competitively blocks Activin A signaling, while BMP2 has a partial blocking activity. Activin A signaling is insensitive to BMP pathway antagonism in HEK293T cells but is strongly inhibited by constitutively active (CA) BMP type 1 receptors. By contrast, the potencies of AB215 and BMP2 are indistinguishable in LβT2 cells and although AB215 blocks Activin A signaling, BMP2 has no inhibitory effect. Unlike HEK293T, Activin A signaling is strongly inhibited by BMP pathway antagonism in LβT2 cells but is largely unaffected by CA BMP type 1 receptors. BMP2 increases phospho-Smad3 levels in LβT2 cells, in both the absence and the presence of Activin A treatment, and augments Activin A-induced FSHβ. AB215 has the opposite effect and sharply decreases basal phospho-Smad3 levels and blocks Smad2 phosphorylation and FSHβ induction resulting from Activin A treatment. These findings together demonstrate that while AB215 activates the BMP pathway, it has opposing effects to those of BMP2 on FSHβ induction in LβT2 cells apparently due to its ability to block Activin A signaling.

  5. Activin A is increased in the nucleus accumbens following a cocaine binge

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    Wang, Zi-Jun; Martin, Jennifer A.; Gancarz, Amy M.; Adank, Danielle N.; Sim, Fraser J.; Dietz, David M.

    2017-01-01

    Drug addiction is a long-lasting disease characterized by compulsive drug intake mediated in part by neuronal and biological adaptations in key brain areas, such as the nucleus accumbens (NAc). While we previously demonstrated involvement of the activin 2a receptor in drug taking, the role of its ligand, activin A, in cocaine relapse is unknown. Activin A levels in the NAc were assessed via ELISA and immunohistochemistry (in neurons, astrocytes, and microglia) following a cocaine binge paradigm. Cocaine exposure significantly increased the levels of activin A in the NAc of animals that had self-administered cocaine prior to the 14-day withdrawal compared with levels in saline controls. This was accompanied by an increase in the proportion of IBA1+ microglia in the NAc that were immunopositive for activin A. In contrast, the proportions of NeuN+ neurons and GFAP+ astrocytes that were immunopositive for activin A remained unaltered. In conclusion, these data suggest that increased secretion of activin A, particularly from microglia, in the NAc represents a novel potential target for the treatment of cocaine relapse. PMID:28272550

  6. Activin A prevents neuron-like PC12 cell apoptosis after oxygen-glucose deprivation

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    Guihua Xu; Zhongxin Xu; Jinting He; Hongliang Guo; Chunli Mei; Jiaoqi Wang; Zhongshu Li; Han Chen; Jing Mang; Hong Yang

    2013-01-01

    In this study, PC12 cells were induced to differentiate into neuron-like cells using nerve growth factor, and were subjected to oxygen-glucose deprivation. Cells were treated with 0, 10, 20, 30, 50, 100 ng/mL exogenous Activin A. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay and Hoechst 33324 staining showed that the survival percentage of PC12 cells significantly decreased and the rate of apoptosis significantly increased after oxygen-glucose deprivation. Exogenous Activin A significantly increased the survival percentage of PC12 cells in a dose-dependent manner. Reverse transcription-PCR results revealed a significant increase in Activin receptor IIA, Smad3 and Smad4 mRNA levels, which are key sites in the Activin A/Smads signaling pathway, in neuron-like cells subjected to oxygen-glucose deprivation, while mRNA expression of the apoptosis-regulation gene caspase-3 decreased. Our experimental findings indicate that exogenous Activin A plays an anti-apoptotic role and protects neurons by means of activating the Activin A/Smads signaling pathway.

  7. Overexpression of activin-A and -B in malignant mesothelioma – Attenuated Smad3 signaling responses and ERK activation promote cell migration and invasive growth

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    Tamminen, Jenni A.; Yin, Miao [Research Programs Unit, Translational Cancer Biology, University of Helsinki (Finland); Transplantation Laboratory, Haartman Institute, University of Helsinki (Finland); Rönty, Mikko [Helsinki University Central Hospital Laboratory, Helsinki (Finland); Department of Pathology, University of Helsinki (Finland); Sutinen, Eva [Helsinki University Central Hospital Laboratory, Helsinki (Finland); Department of Medicine, Division of Pulmonary Medicine, University of Helsinki (Finland); Pasternack, Arja; Ritvos, Olli [Helsinki University Central Hospital Laboratory, Helsinki (Finland); Department of Bacteriology and Immunology, University of Helsinki (Finland); Myllärniemi, Marjukka [Transplantation Laboratory, Haartman Institute, University of Helsinki (Finland); Helsinki University Central Hospital Laboratory, Helsinki (Finland); Department of Medicine, Division of Pulmonary Medicine, University of Helsinki (Finland); Koli, Katri, E-mail: katri.koli@helsinki.fi [Research Programs Unit, Translational Cancer Biology, University of Helsinki (Finland); Transplantation Laboratory, Haartman Institute, University of Helsinki (Finland)

    2015-03-01

    Activin-A and activin-B, members of the TGF-β superfamily, are regulators of reproductive functions, inflammation and wound healing. These dimeric molecules regulate various cellular activities such as proliferation, migration and suvival. Malignant mesothelioma is an asbestos exposure related tumor affecting mainly pleura and it usually has a dismal prognosis. Here, we demonstrate that both activin-A and -B are abundantly expressed in mesothelioma tumor tissue as well as in cultured primary and established mesothelioma cells. Migratory and invasive mesothelioma cells were also found to have attenuated activation of the Smad2/3 pathway in response to activins. Migration and invasive growth of the cells in three-dimentional matrix was prevented by inhibition of activin activity using a soluble activin receptor 2B (sActR2B-Fc). This was associated with decreased ERK activity. Furthermore, migration and invasive growth was significantly inhibited by blocking ERK phosphorylation. Mesothelioma tumors are locally invasive and our results clearly suggest that acivins have a tumor-promoting function in mesothelioma through increasing expression and switching from canonical Smad3 pathway to non-canonical ERK pathway signaling. Blocking activin activity offers a new therapeutic approach for inhibition of mesothelioma invasive growth. - Highlights: • Activin-A and activin-B are highly expressed in mesothelioma. • Mesothelioma cell migration and invasive growth can be blocked with sActR2B. • Activin induced Smad3 activity is attenuated in invasive mesothelioma cells. • Activins induce ERK activity in mesothelioma cells.

  8. Activin signalling and pre-eclampsia: from genetic risk to pre-symptomatic biomarker.

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    Williamson, Rachel D; O'Keeffe, Gerard W; Kenny, Louise C

    2015-02-01

    Pre-eclampsia is a multi-system condition in pregnancy that is characterised by the onset of hypertension and proteinuria in women after the 20th week and it remains a leading cause of maternal and fetal mortality. Despite this the causative molecular basis of pre-eclampsia remains poorly understood. As a result, an intensive research effort has focused on understanding the molecular mechanisms involved in pre-eclampsia and using this information to identify new pre-symptomatic bio-markers of the condition. Activin A and its receptor, ACVR2A, have been extensively studied in this regard. Activin A is a member of the transforming growth factor (TGF)-β superfamily that has a wide range of biological functions depending on the cellular context. Recent work has shown that polymorphisms in ACVR2A may be a genetic risk factor for pre-eclampsia. Furthermore, both placenta and serum levels of Activin A are significantly increased in pre-eclampsia suggesting that Activin A may be a possible biomarker for the condition. Here we review the latest advances in this field and link these with new molecular data that suggest that the oxidative stress and pro-inflammatory cytokine production seen in pre-eclampsia may result in increased placental Activin A secretion in an attempt to maintain placental function.

  9. Differential regulation of follicle stimulating hormone by activin A and TGFB1 in murine gonadotropes

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    Miller William L

    2005-12-01

    Full Text Available Abstract Background Activins stimulate the synthesis of follicle stimulating hormone (FSH in pituitary gonadotropes, at least in part, by inducing transcription of its beta subunit (Fshb. Evidence from several laboratories studying transformed murine LbetaT2 gonadotropes indicates that activins signal through Smad-dependent and/or Smad-independent pathways, similar to those used by transforming growth factor beta-1 (TGFB1 in other cell types. Therefore, given common intracellular signaling mechanisms of these two ligands, we examined whether TGFBs can also induce transcription of Fshb in LbetaT2 cells as well as in purified primary murine gonadotropes. Methods Murine Fshb promoter-reporter (-1990/+1 mFshb-luc activity was measured in LbetaT2 cells treated with activin A or TGFB1, and in cells transfected with either activin or TGFB receptors. The ability of the ligands to stimulate phosphorylation of Smads 2 and 3 in LbetaT2 cells was measured by western blot analysis, and expression of TGFB type I and II receptors was assessed by reverse transcriptase polymerase chain reaction in both LbetaT2 cells and primary gonadotropes purified from male mice of different ages. Finally, regulation of endogenous murine Fshb mRNA levels by activin A and TGFB1 in purified gonadotropes and whole pituitary cultures was measured using quantitative RT-PCR. Results Activin A dose-dependently stimulated -1990/+1 mFshb-luc activity in LbetaT2 cells, but TGFB1 had no effect at doses up to 5 nM. Similarly, activin A, but not TGFB1, stimulated Smad 2 and 3 phosphorylation in these cells. Constitutively active forms of the activin (Acvr1b-T206D and TGFB (TGFBR1-T204D type I receptors strongly stimulated -1990/+1 mFshb-luc activity, showing that mechanisms down stream of Tgfbr1 seem to be intact in LbetaT2 cells. RT-PCR analysis of LbetaT2 cells and whole adult murine pituitaries indicated that both expressed Tgfbr1 mRNA, but that Tgfbr2 was not detected in LbetaT2 cells

  10. Activin A balances Sertoli and germ cell proliferation in the fetal mouse testis.

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    Mendis, Sirisha H S; Meachem, Sarah J; Sarraj, Mai A; Loveland, Kate L

    2011-02-01

    Activin affects many aspects of cellular development, including those essential for reproductive fitness. This study examined the contribution of activin A to murine fetal testicular development, revealing contrasting outcomes of activin actions on Sertoli cells and gonocytes. Shortly after sex determination, from Embryonic Day 12.5 (E12.5) through to birth (0 dpp), the activin A subunit transcript (Inhba) level rises in testis but not ovary, followed closely by the Inha transcript (encoding the inhibitory inhibin alpha subunit). Activin receptor transcript levels also change, with Acvr1 (encoding ALK2) and Acvr2b (ActRIIB) significantly higher and lower, respectively, at 0 dpp compared with E13.5 and E15.5. Transcripts encoding the signaling mediators Smad1, Smad3, and Smad4 were higher at 0 dpp compared with E13.5 and E15.5, whereas Smad2, Smad5, and Smad7 were lower. Detection of phosphorylated (P-)SMAD2/3 in nearly all testis cell nuclei indicated widespread transforming growth factor beta (TGFB) and/or activin ligand signaling activity. In contrast to wild-type littermates, activin betaA subunit knockout (Inhba(-/-)) mice have significantly smaller testes at birth, attributable to a 50% lower Sertoli cell number and decreased Sertoli cell proliferation from E13.5. Inhba(-/-) testes contained twice the normal gonocyte number at birth, with some appearing to bypass quiescence. Persistence of widespread P-SMAD2/3 in Inhba(-/-) cells indicates other TGFB superfamily ligands are active in fetal testes. Significant differences in Smad and cell cycle regulator transcript levels correlating to Inhba gene dosage correspond to differences in Sertoli and germ cell numbers. In Inhba(-/-) testes, Cdkn1a (encoding p21(cip1)), identified previously in fetal gonocytes, was lower at E13.5, whereas Cdkn1b (encoding p(27kip1) in somatic cells) was lower at birth, and cyclin D2 mRNA and protein were lower at E15.5 and 0 dpp. Thus, activin A dosage contributes to establishing the

  11. Activin and TGF-β effects on brain development and neural stem cells.

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    Rodríguez-Martínez, Griselda; Velasco, Iván

    2012-11-01

    Transforming Growth Factor-β (TGF-β) family members are ubiquitously expressed, participating in the regulation of many processes in different cell types both in embryonic and adult stages. Several members of this family, including Activins, TGF-β1-3 and Nodal, have been implicated in the development and maintenance of various organs, in which stem cells play important roles. Although TGF-β was initially considered an injury-related cytokine, it became clear that not only TGF-β, but other members of this family, play critical roles in morphogenesis and cell lineage specification. During brain development, Activin and TGF-βs as well as their cognate receptors, are expressed in different patterns. The roles of Activin and TGF-β during CNS development are sometimes contradictory, because these proteins present different actions depending on the cell type and the context. The aim of this review is to summarize current information on the actions of TGF-β members during developing brain, and also on Neural Stem/Progenitor Cells (NSPC). We focus on the TGF-β subgroup, specifically on the effects of TGF-β1 and Activin A. In the first section we describe the main characteristics of the ligands, its receptors as well as the proteins and mechanisms involved in signaling. Next, we discuss the main advances concerning TGF-β1 and Activin actions during brain development and their roles in NSPC fate decision and neuroprotection both in vitro and in vivo. The emerging picture from these studies suggests that these growth factors can be used to manipulate neurogenesis and might help to achieve restoration after brain deterioration.

  12. Activin A secreted by human mesenchymal stem cells induces neuronal development and neurite outgrowth in an in vitro model of Alzheimer's disease: neurogenesis induced by MSCs via activin A.

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    Park, Sang Eon; Lee, Jeongmin; Chang, Eun Hyuk; Kim, Jong Hwa; Sung, Ji-Hee; Na, Duk L; Chang, Jong Wook

    2016-08-01

    Alzheimer's disease (AD) is characterized by progressive loss of memory in addition to cortical atrophy. Cortical atrophy in AD brains begins in the parietal and temporal lobes, which are near the subventricular zone (SVZ). The aim of this study was to activate the neurogenesis in the SVZ of AD brains by human mesenchymal stem cells (hMSCs). Neural stem cells (NSCs) were isolated from SVZ of 4-month-old 5XFAD mice. Co-culture of hMSCs with SVZ-derived NSCs from 5XFAD mice induced neuronal development and neurite outgrowth. To examine the inducing factor of neurogenesis, human cytokine array was performed with co-cultured media, and revealed elevated release of activin A from hMSCs. Also, we confirmed that the mRNA levels of activin A and activin receptor in the SVZ of 5XFAD mice were significantly lower than normal mice. Treatment of human recombinant activin A in SVZ-derived NSCs from 5XFAD mice induced neuronal development and neurite outgrowth. These data suggest that use of hMSCs and activin A to recover neurogenesis in future studies of cortical regeneration to treat AD.

  13. Testicular activin and follistatin levels are elevated during the course of experimental autoimmune epididymo–orchitis in mice

    Science.gov (United States)

    Nicolas, Nour; Michel, Vera; Bhushan, Sudhanshu; Wahle, Eva; Hayward, Susan; Ludlow, Helen; de Kretser, David M.; Loveland, Kate L.; Schuppe, Hans-Christian; Meinhardt, Andreas; Hedger, Mark P.; Fijak, Monika

    2017-01-01

    Experimental autoimmune epididymo-orchitis (EAEO) is a model of chronic inflammation, induced by immunisation with testicular antigens, which reproduces the pathology of some types of human infertility. Activins A and B regulate spermatogenesis and steroidogenesis, but are also pro-inflammatory, pro-fibrotic cytokines. Expression of the activins and their endogenous antagonists, inhibin and follistatin, was examined in murine EAEO. Adult untreated and adjuvant-treated control mice showed no pathology. All mice immunised with testis antigens developed EAEO by 50 days, characterised by loss of germ cells, immune cell infiltration and fibrosis in the testis, similar to biopsies from human inflamed testis. An increase of total CD45+ leukocytes, comprising CD3+ T cells, CD4 + CD8− and CD4 + CD25+ T cells, and a novel population of CD4 + CD8+ double positive T cells was also detected in EAEO testes. This was accompanied by increased expression of TNF, MCP-1 and IL-10. Activin A and B and follistatin protein levels were elevated in EAEO testes, with peak activin expression during the active phase of the disease, whereas mRNA expression of the inhibin B subunits (Inha and Inhbb) and activin receptor subunits (Acvr1b and Acvr2b) were downregulated. These data suggest that activin–follistatin regulation may play a role during the development of EAEO. PMID:28205525

  14. Xnrs and activin regulate distinct genes during Xenopus development: activin regulates cell division.

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    Joana M Ramis

    Full Text Available BACKGROUND: The mesoderm of the amphibian embryo is formed through an inductive interaction in which vegetal cells of the blastula-staged embryo act on overlying equatorial cells. Candidate mesoderm-inducing factors include members of the transforming growth factor type beta family such as Vg1, activin B, the nodal-related proteins and derrière. METHODOLOGY AND PRINCIPLE FINDINGS: Microarray analysis reveals different functions for activin B and the nodal-related proteins during early Xenopus development. Inhibition of nodal-related protein function causes the down-regulation of regionally expressed genes such as chordin, dickkopf and XSox17alpha/beta, while genes that are mis-regulated in the absence of activin B tend to be more widely expressed and, interestingly, include several that are involved in cell cycle regulation. Consistent with the latter observation, cells of the involuting dorsal axial mesoderm, which normally undergo cell cycle arrest, continue to proliferate when the function of activin B is inhibited. CONCLUSIONS/SIGNIFICANCE: These observations reveal distinct functions for these two classes of the TGF-beta family during early Xenopus development, and in doing so identify a new role for activin B during gastrulation.

  15. Identification and expression of Smads associated with TGF-beta/activin/nodal signaling pathways in the rainbow trout (Oncorhynuchus mykiss)

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    The Smad proteins are essential components of the TGF-beta/activin/nodal family signaling pathway. We report the identification and characterization of transcripts representing 3 receptor Smads (Smad2a, Smad2b, Smad3), 2 common Smads (Smad4a, Smad4b) and one inhibitory Smad (Smad7). Phylogenetic an...

  16. Serum activin B concentration as predictive biomarker for ectopic pregnancy.

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    Dhiman, Pooja; Senthilkumar, G P; Rajendiran, Soundravally; Sivaraman, K; Soundararaghavan, S; Kulandhasamy, Maheshwari

    2016-05-01

    We evaluated the diagnostic accuracy of activin B in discriminating tubal ectopic pregnancy (tEP) from intrauterine miscarriages (IUM), and normal viable intrauterine pregnancy (IUP). We included 28 women with tEP, 31 women with IUM, and 29 normal IUP, confirmed both by clinical examination and ultrasonography. Serum activin B concentration was measured at the time of admission using the ELISA kit. The median serum activin B concentration was found to be significantly decreased in both tEP (p=0.004) and IUM (p=0.022) compared to normal IUP. When compared between tEP and IUM, activin B concentrations did not differ significantly. ROC analysis of activin B and free β-hCG demonstrated AUC of 0.722 and 0.805, respectively to discriminate tEP from viable IUP. The model including both activin B and free β-hCG improved the discriminating potential with greater AUC (0.824), and specificity (93%) than individual one. To discriminate tEP from IUM, activin B, free β-hCG and combination of both performed poorly. We conclude that serum activin B concentration is lower in tubal ectopic pregnancy, and can discriminate it from normal pregnancy with moderate accuracy. It also shows improved diagnostic potential along with free β-hCG, but cannot distinguish tEP from IUM reliably.

  17. An Activin A/BMP2 chimera displays bone healing properties superior to those of BMP2

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    Yoon, Byung-Hak; Esquivies, Luis; Ahn, Chihoon; Gray, Peter C.; Ye, Sang-kyu; Kwiatkowski, Witek; Choe, Senyon

    2014-01-01

    Recombinant Bone Morphogenetic Protein 2 (rhBMP2) has been used clinically to treat bone fractures in human patients. However, the high doses of rhBMP2 required for a therapeutic response can cause undesirable side effects. Here, we demonstrate that a novel Activin A/BMP2 (AB2) chimera, AB204, promotes osteogenesis and bone healing much more potently and effectively than rhBMP2. Remarkably, 1 month of AB204 treatment completely heals tibial and calvarial defects of critical size in mice at a concentration 10-fold lower than a dose of rhBMP2 that only partially heals the defect. We determine the structure of AB204 to 2.3 Å that reveals a distinct BMP2-like fold in which the Activin A sequence segments confer insensitivity to the BMP2 antagonist Noggin and an affinity for the Activin/BMP type II receptor ActRII that is 100-fold greater than that of BMP2. The structure also led to our identification of a single Activin A-derived amino acid residue which when mutated to the corresponding BMP2 residue resulted in a significant increase in the affinity of AB204 for its type I receptor BMPRIa and a further enhancement in AB204's osteogenic potency. Together, these findings demonstrate that rationally designed AB2 chimeras can provide BMP2 substitutes with enhanced potency for treating non-union bone fractures. PMID:24692083

  18. An activin A/BMP2 chimera, AB204, displays bone-healing properties superior to those of BMP2.

    Science.gov (United States)

    Yoon, Byung-Hak; Esquivies, Luis; Ahn, Chihoon; Gray, Peter C; Ye, Sang-Kyu; Kwiatkowski, Witek; Choe, Senyon

    2014-09-01

    Recombinant bone morphogenetic protein 2 (rhBMP2) has been used clinically to treat bone fractures in human patients. However, the high doses of rhBMP2 required for a therapeutic response can cause undesirable side effects. Here, we demonstrate that a novel Activin A/BMP2 (AB2) chimera, AB204, promotes osteogenesis and bone healing much more potently and effectively than rhBMP2. Remarkably, 1 month of AB204 treatment completely heals tibial and calvarial defects of critical size in mice at a concentration 10-fold lower than a dose of rhBMP2 that only partially heals the defect. We determine the structure of AB204 to 2.3 Å that reveals a distinct BMP2-like fold in which the Activin A sequence segments confer insensitivity to the BMP2 antagonist Noggin and an affinity for the Activin/BMP type II receptor ActRII that is 100-fold greater than that of BMP2. The structure also led to our identification of a single Activin A-derived amino acid residue, which, when mutated to the corresponding BMP2 residue, resulted in a significant increase in the affinity of AB204 for its type I receptor BMPRIa and a further enhancement in AB204's osteogenic potency. Together, these findings demonstrate that rationally designed AB2 chimeras can provide BMP2 substitutes with enhanced potency for treating non-union bone fractures.

  19. TGFβ/Activin signalling is required for ribosome biogenesis and cell growth in Drosophila salivary glands

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    Eusebio, Nadia; Correia, Andreia; Marinho, Joana; Casares, Fernando

    2017-01-01

    Signalling by TGFβ superfamily factors plays an important role in tissue growth and cell proliferation. In Drosophila, the activity of the TGFβ/Activin signalling branch has been linked to the regulation of cell growth and proliferation, but the cellular and molecular basis for these functions are not fully understood. In this study, we show that both the RII receptor Punt (Put) and the R-Smad Smad2 are strongly required for cell and tissue growth. Knocking down the expression of Put or Smad2 in salivary glands causes alterations in nucleolar structure and functions. Cells with decreased TGFβ/Activin signalling accumulate intermediate pre-rRNA transcripts containing internal transcribed spacer 1 regions accompanied by the nucleolar retention of ribosomal proteins. Thus, our results show that TGFβ/Activin signalling is required for ribosomal biogenesis, a key aspect of cellular growth control. Importantly, overexpression of Put enhanced cell growth induced by Drosophila Myc, a well-characterized inducer of nucleolar hypertrophy and ribosome biogenesis. PMID:28123053

  20. Neuroprotective effects of Activin A on endoplasmic reticulum stress-mediated apoptotic and autophagic PC12 cell death

    Directory of Open Access Journals (Sweden)

    Long-xing Xue

    2017-01-01

    Full Text Available Activin A, a member of the transforming growth factor-beta superfamily, plays a neuroprotective role in multiple neurological diseases. Endoplasmic reticulum (ER stress-mediated apoptotic and autophagic cell death is implicated in a wide range of diseases, including cerebral ischemia and neurodegenerative diseases. Thapsigargin was used to induce PC12 cell death, and Activin A was used for intervention. Our results showed that Activin A significantly inhibited morphological changes in thapsigargin-induced apoptotic cells, and the expression of apoptosis-associated proteins [cleaved-caspase-12, C/EBP homologous protein (CHOP and cleaved-caspase-3] and biomarkers of autophagy (Beclin-1 and light chain 3, and downregulated the expression of thapsigargin-induced ER stress-associated proteins [inositol requiring enzyme-1 (IRE1, tumor necrosis factor receptor-associated factor 2 (TRAF2, apoptosis signal-regulating kinase 1 (ASK1, c-Jun N-terminal kinase (JNK and p38]. The inhibition of thapsigargin-induced cell death was concentration-dependent. These findings suggest that administration of Activin A protects PC12 cells against ER stress-mediated apoptotic and autophagic cell death by inhibiting the activation of the IRE1-TRAF2-ASK1-JNK/p38 cascade.

  1. EXPRESSION OF ACTIVIN DURING THE MANDIBULAR DISTRACTION OSTEOGENESIS IN RABBIT

    Institute of Scientific and Technical Information of China (English)

    李昕; 祁佐良; 王炜; 董佳生; 林晓曦; 戴传昌

    2002-01-01

    Objective To investigate the role of activin on osteogenesis during mandibular distraction.Methods Rabbit mandibular distraction model was used and the new regenerating tissue in the distraction zone were harvested at different time points. lmmunohistochemical technique for activin A was performed in the harvested tissues. Results Positive stain was noted in early phases of distraction. At the end of distraction phase osteoblasts and osteoid in primary mineralization front were strongly stained and osteoblasts and osteocytes in peripheral new bone zone were moderately stained. There were also broad activin A stains in osteoblasts and active osteocytes in early consolidation phase. Conclusion The expression of activin is increased during mandibular distraction. It could play an important role in the process of osteoblastic cells secretion, differentiation to osteocytes and bone formation during mandibular distraction.

  2. Role of Activin A in Immune Responses to Breast Cancer

    Science.gov (United States)

    2013-12-01

    secretion of activin A induced by radiation of breast tumor cells is functionally relevant since it further decreases DC maturation and enhances Treg ...regulatory T cells ( Treg ). Recent data indicate that activin A is expressed by some tumors, including breast cancer. Radiotherapy (RT) has the ability to...convert a tumor into an in situ vaccine, but the concomitant increase in Treg has been suggested to hinder its pro-immunogenic effects. Here we

  3. Activation of FGFR(IIIc) isoforms promotes activin-induced mesendoderm development in mouse embryonic stem cells and reduces Sox17 coexpression in EpCAM+ cells.

    Science.gov (United States)

    Peterslund, Janny M L; Serup, Palle

    2011-05-01

    Activin induces the formation of definitive endoderm from mouse ES cells dependent on active fibroblast growth factor (Fgf) signaling. Here we report that Fgf4 is dispensable for activin A-induced differentiation of mouse ES cells into endoderm. We find that Fgf4(-/-) cells readily differentiate into definitive endoderm without exogenous administration of Fgf4. Additionally, we investigate the spatio-temporal dynamics of Fgf receptor (FGFR) isoform distribution in activin A-treated ES cell cultures and find that FGFR(III)c isoforms are expressed in DE as well as non-DE populations, whereas FGFR2(III)b and FGFR4 are found specifically enriched in the DE fraction. Ligands that preferentially activate the FGFR(III)c isoforms induce mesendoderm markers T and Gsc, but reduce expression of the DE marker Sox17 in activin-induced EpCAM(+) cells. In contrast, ligands specifically activating FGFR(III)b isoforms have no effect on either population. Activation of FGFR(III)c isoforms results in a strong mitogenic effect on activin A-induced ES cell progeny early in the differentiation period whereas activation of FGFR(III)b isoforms has only a moderate mitogenic effect confined to the late differentiation period. We conclude that FGFR(III)c-isoform activation selectively drives the differentiation of mES cells toward mesendoderm and that Fgf4 is dispensable for the differentiation into definitive endoderm.

  4. 激活素A促进鸡胚背根神经节神经突起生长的作用机制%Effect mechanism of activin A in neurite outgrowth of embryonic dorsal root ganglia of the chicken

    Institute of Scientific and Technical Information of China (English)

    方琳; 王轶楠; 刘海岩; 李晨光; 李继茹; 柳忠辉

    2012-01-01

    采用半定量PCR检测激活素II型受体(ActRII)、钙基因相关肽(cGRP)、血管活性肠肽(VIP)mRNA表达,液相一质谱联用仪检测5-羟色胺释放水平。结果显示,5μg/L激活素A能明显促进鸡胚背根神经节神经突起生长,同时可见激活素A促进ActRIIA、CGRPmRNA表达及神经递质5-羟色胺释放,但对ActRIIB及VIPmRNA表达无影响。结果表明,ActivinA可能通过ActivinA—ActRIIA途径发挥作用,其促进鸡胚背根神经节神经突起生长与其上调CGRP表达及5-HT释放有关。%To investigate the effect mechanism of activin A in neurite outgrowth of embryonic dorsal root ganglia (DRG) of the chiken. ActRII,CGRP and VIP mRNA expressions were analyzed by semi-quantitative RT-PCR, and the secretion of serotonin (5-HT) was examined by liquid chromatography-tandem mass spectrometry (LC/MS). Activin A significantly induced neurite outgrowth of DRG and up-regulated the mRNA expressions of the activin receptor type IIA (ActRIIA) and CGRP in DRG. In addition,activin A stimulated 5-HT release from DRG. Activin A might stimulate DRG neurite outgrowth via activin A-ActRIIA pathway and promoting CGRP expression and 5-HT secretion.

  5. Mutations in inhibin and activin genes associated with human disease.

    Science.gov (United States)

    Shelling, Andrew N

    2012-08-15

    Inhibins and activins are members of the transforming growth factor (TGFβ) superfamily, that includes the TGFβs, inhibins and activins, bone morphogenetic proteins (BMPs) and growth and differentiation factors (GDFs). The family members are expressed throughout the human body, and are involved in the regulation of a range of important functions. The precise regulation of the TGFβ pathways is critical, and mutations of individual molecules or even minor alterations of signalling will have a significant affect on function, that may lead to development of disease or predisposition to the development of disease. The inhibins and activins regulate aspects of the male and female reproductive system, therefore, it is not surprising that most of the diseases associated with abnormalities of the inhibin and activin genes are focused on reproductive disorders and reproductive cancers. In this review, I highlight the role of genetic variants in the development of conditions such as premature ovarian failure, pre-eclampsia, and various reproductive cancers. Given the recent advances in human genetic research, such as genome wide association studies and next generation sequencing, it is likely that inhibins and activins will be shown to play more important roles in a range of human genetic diseases in the future.

  6. Activins and Inhibins: novel regulators of thymocyte development

    Science.gov (United States)

    Licona-Limón, Paula; Alemán-Muench, German; Chimal-Monroy, Jesus; Macías-Silva, Marina; García-Zepeda, Eduardo A.; Matzuk, Martin M.; Fortoul, Teresa I.; Soldevila, Gloria

    2009-01-01

    Activins and inhibins are members of the transforming growth factor β superfamily that act on different cell types and regulate a broad range of cellular processes including proliferation, differentiation, and apoptosis. Here, we provide the first evidence that activins and inhibins regulate specific checkpoints during thymocyte development. We demonstrate that both activin A and inhibin A promote the DN3-DN4 transition in vitro, although they differentially control the transition to the DP stage. Whereas activin A induces the accumulation of a CD8+CD24hiTCRβlo intermediate subpopulation, inhibin A promotes the differentiation of DN4 to DP. In addition, both activin A and inhibin A appear to promote CD8+SP differentiation Moreover, Inhibin α null mice have delayed in vitro T cell development, showing both a decrease in the DN-DP transition and reduced thymocyte numbers, further supporting a role for inhibins in the control of developmental signals taking place during T cell differentiation in vivo. PMID:19338778

  7. Efficient retina formation requires suppression of both Activin and BMP signaling pathways in pluripotent cells

    Directory of Open Access Journals (Sweden)

    Kimberly A. Wong

    2015-03-01

    Full Text Available Retina formation requires the correct spatiotemporal patterning of key regulatory factors. While it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only Noggin, a known BMP antagonist, can convert pluripotent Xenopus laevis animal cap cells to functional retinal cells. The aim of this study is to determine the intracellular molecular events that occur during this conversion. Surprisingly, blocking BMP signaling alone failed to mimic Noggin treatment. Overexpressing Noggin in pluripotent cells resulted in a concentration-dependent suppression of both Smad1 and Smad2 phosphorylation, which act downstream of BMP and Activin signaling, respectively. This caused a decrease in downstream targets: endothelial marker, xk81, and mesodermal marker, xbra. We treated pluripotent cells with dominant-negative receptors or the chemical inhibitors, dorsomorphin and SB431542, which each target either the BMP or Activin signaling pathway. We determined the effect of these treatments on retina formation using the Animal Cap Transplant (ACT assay; in which treated pluripotent cells were transplanted into the eye field of host embryos. We found that inhibition of Activin signaling, in the presence of BMP signaling inhibition, promotes efficient retinal specification in Xenopus tissue, mimicking the affect of adding Noggin alone. In whole embryos, we found that the eye field marker, rax, expanded when adding both dominant-negative Smad1 and Smad2, as did treating the cells with both dorsomorphin and SB431542. Future studies could translate these findings to a mammalian culture assay, in order to more efficiently produce retinal cells in culture.

  8. Intertwining of Activin A and TGFβ Signaling: Dual Roles in Cancer Progression and Cancer Cell Invasion

    Energy Technology Data Exchange (ETDEWEB)

    Loomans, Holli A. [Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Andl, Claudia D., E-mail: claudia.andl@vanderbilt.edu [Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Vanderbilt Digestive Disease Center, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Vanderbilt Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232 (United States)

    2014-12-30

    In recent years, a significant amount of research has examined the controversial role of activin A in cancer. Activin A, a member of the transforming growth factor β (TGFβ) superfamily, is best characterized for its function during embryogenesis in mesoderm cell fate differentiation and reproduction. During embryogenesis, TGFβ superfamily ligands, TGFβ, bone morphogenic proteins (BMPs) and activins, act as potent morphogens. Similar to TGFβs and BMPs, activin A is a protein that is highly systemically expressed during early embryogenesis; however, post-natal expression is overall reduced and remains under strict spatiotemporal regulation. Of importance, normal post-natal expression of activin A has been implicated in the migration and invasive properties of various immune cell types, as well as endometrial cells. Aberrant activin A signaling during development results in significant morphological defects and premature mortality. Interestingly, activin A has been found to have both oncogenic and tumor suppressor roles in cancer. Investigations into the role of activin A in prostate and breast cancer has demonstrated tumor suppressive effects, while in lung and head and neck squamous cell carcinoma, it has been consistently shown that activin A expression is correlated with increased proliferation, invasion and poor patient prognosis. Activin A signaling is highly context-dependent, which is demonstrated in studies of epithelial cell tumors and the microenvironment. This review discusses normal activin A signaling in comparison to TGFβ and highlights how its dysregulation contributes to cancer progression and cell invasion.

  9. Inhibition of somatotroph growth and growth hormone biosynthesis by activin in vitro

    DEFF Research Database (Denmark)

    Billestrup, Nils; González-Manchón, C; Potter, E

    1990-01-01

    ]methionine-labeled cells, could be observed after 24 h of activin treatment, and maximal (70%) inhibition of GH biosynthesis was observed after 3 days. Activin inhibited basal as well as GH-releasing factor (GRF)-, glucocorticoid-, and thyroid hormone-stimulated GH biosynthesis. Inhibin, which is known to reverse...... the effect of activin on FSH secretion, did not reverse the effect of activin on GH biosynthesis. Treatment of somatotrophs with activin for 3 days completely inhibited the growth-promoting effect of GRF on somatotrophs. However, no effect of activin on GRF-stimulated expression of the c-fos protooncogene...... was observed. These data demonstrate that activin, in addition to its stimulatory effect on FSH secretion, is able to inhibit both expression of GH and growth of somatotropic cells....

  10. Neuroprotective Effects of Exogenous Activin A on Oxygen-Glucose Deprivation in PC12 Cells

    Directory of Open Access Journals (Sweden)

    Zhong-Xin Xu

    2011-12-01

    Full Text Available Ischemic cerebrovascular disease is one of the most common causes of death in the World. Exogenous activin A (ActA protects neurons against toxicity and plays a central role in regulating the brain’s response to injury. In the present study, we investigated the mechanisms involved in the neuroprotective effects of ActA in a model of hypoxic-ischemic brain disease. We found that ActA could effectively increase the survival rate of PC12 cells and relieve oxygen-glucose deprivation (OGD damage. To clarify the neuroprotective mechanisms of ActA, the effects of ActA on the ActA/Smad pathway and on the up-regulation of inducible nitric oxide synthase (NOS and superoxide dismutase (SOD were investigated using OGD in PC12 cells. The results showed that ActA could increase the expression of activin receptor IIA (ActRIIA, Smad3 and Smad4 and that 50 ng/mL and 100 ng/mL of ActA could reduce NO levels and increase SOD activity by 78.9% and 79.9%, respectively. These results suggested that the neuroprotective effects of ActA in ischemia could be related to the activation of the ActA/Smad signaling pathway and to its anti-oxidant activities.

  11. La fonction de la voie de signalisation du récepteur Activin de type IIB dans le muscle squelettique adulte.

    OpenAIRE

    Relizani, Karima

    2014-01-01

    Myostatin, a growth factor of the TGF-β family that signals through the activin receptor-IIB (ActRIIB), has been identified as an important negative regulator of skeletal muscle growth. However, its effect on muscle energy metabolism and energy dependent muscle function remains largely unexplored. I here investigated the consequence of impaired ActRIIB signaling for muscle metabolism in two experimental models, i) the constitutive myostatin knockout mice and ii) following pharmacological admi...

  12. Activin A Levels Are Associated With Abnormal Glucose Regulation in Patients With Myocardial Infarction

    Science.gov (United States)

    Andersen, Geir Ø.; Ueland, Thor; Knudsen, Eva C.; Scholz, Hanne; Yndestad, Arne; Sahraoui, Afaf; Smith, Camilla; Lekva, Tove; Otterdal, Kari; Halvorsen, Bente; Seljeflot, Ingebjørg; Aukrust, Pål

    2011-01-01

    OBJECTIVE On the basis of the role of activin A in inflammation, atherogenesis, and glucose homeostasis, we investigated whether activin A could be related to glucometabolic abnormalities in patients with acute myocardial infarction (MI). RESEARCH DESIGN AND METHODS Activin A measurement and oral glucose tolerance tests (OGTTs) were performed in patients (n = 115) with acute MI, without previously known diabetes, and repeated after 3 months. Release of activin A and potential anti-inflammatory effects of activin A were measured in human endothelial cells. Activin A effects on insulin secretion and inflammation were tested in human pancreatic islet cells. RESULTS 1) In patients with acute MI, serum levels of activin A were significantly higher in those with abnormal glucose regulation (AGR) compared with those with normal glucose regulation. Activin A levels were associated with the presence of AGR 3 months later (adjusted odds ratio 5.1 [95% CI 1.73–15.17], P = 0.003). 2) In endothelial cells, glucose enhanced the release of activin A, whereas activin A attenuated the release of interleukin (IL)-8 and enhanced the mRNA levels of the antioxidant metallothionein. 3) In islet cells, activin A attenuated the suppressive effect of inflammatory cytokines on insulin release, counteracted the ability of these inflammatory cytokines to induce mRNA expression of IL-8, and induced the expression of transforming growth factor-β. CONCLUSIONS We found a significant association between activin A and newly detected AGR in patients with acute MI. Our in vitro findings suggest that this association represents a counteracting mechanism to protect against inflammation, hyperglycemia, and oxidative stress. PMID:21464440

  13. Activin A inhibits BMP-signaling by binding ACVR2A and ACVR2B

    DEFF Research Database (Denmark)

    Olsen, Oddrun Elise; Wader, Karin Fahl; Hella, Hanne;

    2015-01-01

    BACKGROUND: Activins are members of the TGF-β family of ligands that have multiple biological functions in embryonic stem cells as well as in differentiated tissue. Serum levels of activin A were found to be elevated in pathological conditions such as cachexia, osteoporosis and cancer. Signaling...

  14. Developmentally regulated SMAD2 and SMAD3 utilization directs activin signalling outcomes

    Science.gov (United States)

    Itman, Catherine; Small, Chris; Griswold, Michael; Nagaraja, Ankur K.; Matzuk, Martin M.; Brown, Chester; Jans, David A.; Loveland, Kate L.

    2010-01-01

    Activin is required for testis development. Activin signals via the phosphorylation and nuclear accumulation of SMAD2 and SMAD3. We present novel findings of developmentally regulated activin signalling leading to specific transcriptional outcomes in testicular Sertoli cells. In immature, proliferating, Sertoli cells, activin A induces nuclear accumulation of SMAD3, but not SMAD2, although both proteins become phosphorylated. In post-mitotic differentiating cells, both SMAD proteins accumulate in the nucleus. Furthermore, immature Sertoli cells are sensitive to activin dosage; higher concentrations induce maximal SMAD3 nuclear accumulation and a small increase in nuclear SMAD2. Microarray analysis identified distinct transcriptional outcomes correlating with differential SMAD utilization and new activin target genes, including Gja1 and Serpina5, which are essential for Sertoli cell development and male fertility. In transgenic mice with altered activin bioactivity that display fertility phenotypes, Gja1 and Serpina5 are significantly altered. Thus, differential SMAD utilization in response to activin features during Sertoli cell maturation. PMID:19517569

  15. Activin B promotes epithelial wound healing in vivo through RhoA-JNK signaling pathway.

    Directory of Open Access Journals (Sweden)

    Min Zhang

    Full Text Available BACKGROUND: Activin B has been reported to promote the proliferation and migration of keratinocytes in vitro via the RhoA-JNK signaling pathway, whereas its in vivo role and mechanism in wound healing process has not yet been elucidated. PRINCIPAL FINDINGS: In this study, we explored the potential mechanism by which activin B induces epithelial wound healing in mice. Recombinant lentiviral plasmids, with RhoA (N19 and RhoA (L63 were used to infect wounded KM mice. The wound healing process was monitored after different treatments. Activin B-induced cell proliferation on the wounded skin was visualized by electron microscopy and analyzed by 5'-bromodeoxyuridine (BrdU incorporation assay. Protein expression of p-JNK or p-cJun was determined by immunohistochemical staining and immunoblotting analysis. Activin B efficiently stimulated the proliferation of keratinocytes and hair follicle cells at the wound area and promoted wound closure. RhoA positively regulated activin B-induced wound healing by up-regulating the expression of p-JNK and p-cJun. Moreover, suppression of RhoA activation delayed activin B-induced wound healing, while JNK inhibition recapitulated phenotypes of RhoA inhibition on wound healing. CONCLUSION: These results demonstrate that activin B promotes epithelial wound closure in vivo through the RhoA-Rock-JNK-cJun signaling pathway, providing novel insight into the essential role of activin B in the therapy of wound repair.

  16. Gram-Negative Bacterial Lipopolysaccharide Stimulates Activin A Secretion from Human Amniotic Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yumiko Abe

    2013-01-01

    Full Text Available Activin A is involved in inflammation. The present study was performed to clarify if lipopolysaccharide, a component of Gram-negative bacteria, stimulates activin A secretion from human amniotic epithelial cells and to determine if activin A plays a role in amnionitis. Fetal membranes were obtained during elective cesarean sections performed in full-term pregnancies of patients without systemic disease, signs of premature delivery, or fetal complications. Amniotic epithelial cells were isolated by trypsinization. The activin A concentrations in the culture media were measured by enzyme-linked immunosorbent assay, and cell proliferation was assessed by 5-bromo-2′-deoxyuridine incorporation. Amniotic epithelial cells secreted activin A in a cell density-dependent manner, and lipopolysaccharide (10 μg/mL enhanced the secretion at each cell density. Lipopolysaccharide (10–50 μg/mL also stimulated activin A secretion in a dose-dependent manner. Contrary to the effect of activin A secretion, lipopolysaccharide inhibited cell proliferation in amniotic epithelial cells. The present study suggests that lipopolysaccharide stimulation of activin A secretion may be a mechanism in the pathogenesis of amnionitis.

  17. Activin B mediated induction of Pdx1 in human embryonic stem cell derived embryoid bodies

    DEFF Research Database (Denmark)

    Frandsen, Ulrik; Pørneki, Ann Dorte Storm; Floridon, Charlotte

    2007-01-01

    Human embryonic stem cells (hESCs) have the potential to provide alternative sources for pancreatic islet grafts. In the present study we have investigated the influence of Activin A and Activin B on the expression of the pancreas marker gene Pdx1 in hESCs differentiated as embryoid bodies (EBs...

  18. Increased activin bioavailability enhances hepatic insulin sensitivity while inducing hepatic steatosis in male mice.

    Science.gov (United States)

    Ungerleider, Nathan A; Bonomi, Lara M; Brown, Melissa L; Schneyer, Alan L

    2013-06-01

    The development of insulin resistance is tightly linked to fatty liver disease and is considered a major health concern worldwide, although their mechanistic relationship remains controversial. Activin has emerging roles in nutrient homeostasis, but its metabolic effects on hepatocytes remain unknown. In this study, we investigated the effects of increased endogenous activin bioactivity on hepatic nutrient homeostasis by creating mice with inactivating mutations that deplete the circulating activin antagonists follistatin-like-3 (FSTL3) or the follistatin 315 isoform (FST315; FST288-only mice). We investigated liver histology and lipid content, hepatic insulin sensitivity, and metabolic gene expression including the HepG2 cell and primary hepatocyte response to activin treatment. Both FSTL3-knockout and FST288-only mice had extensive hepatic steatosis and elevated hepatic triglyceride content. Unexpectedly, insulin signaling, as assessed by phospho-Akt (a.k.a. protein kinase B), was enhanced in both mouse models. Pretreatment of HepG2 cells with activin A increased their response to subsequent insulin challenge. Gene expression analysis suggests that increased lipid uptake, enhanced de novo lipid synthesis, decreased lipolysis, and/or enhanced glucose uptake contribute to increased hepatic triglyceride content in these models. However, activin treatment recapitulated only some of these gene changes, suggesting that increased activin bioactivity may be only partially responsible for this phenotype. Nevertheless, our results indicate that activin enhances hepatocyte insulin response, which ultimately leads to hepatic steatosis despite the increased insulin sensitivity. Thus, regulation of activin bioactivity is critical for maintaining normal liver lipid homeostasis and response to insulin, whereas activin agonists may be useful for increasing liver insulin sensitivity.

  19. Activin signal promotes cancer progression and is involved in cachexia in a subset of pancreatic cancer.

    Science.gov (United States)

    Togashi, Yosuke; Kogita, Akihiro; Sakamoto, Hiroki; Hayashi, Hidetoshi; Terashima, Masato; de Velasco, Marco A; Sakai, Kazuko; Fujita, Yoshihiko; Tomida, Shuta; Kitano, Masayuki; Okuno, Kiyotaka; Kudo, Masatoshi; Nishio, Kazuto

    2015-01-28

    We previously reported that activin produces a signal with a tumor suppressive role in pancreatic cancer (PC). Here, the association between plasma activin A and survival in patients with advanced PC was investigated. Contrary to our expectations, however, patients with high plasma activin A levels had a significantly shorter survival period than those with low levels (median survival, 314 days vs. 482 days, P = 0.034). The cellular growth of the MIA PaCa-2 cell line was greatly enhanced by activin A via non-SMAD pathways. The cellular growth and colony formation of an INHBA (beta subunit of inhibin)-overexpressed cell line were also enhanced. In a xenograft study, INHBA-overexpressed cells tended to result in a larger tumor volume, compared with a control. The bodyweights of mice inoculated with INHBA-overexpressed cells decreased dramatically, and these mice all died at an early stage, suggesting the occurrence of activin-induced cachexia. Our findings indicated that the activin signal can promote cancer progression in a subset of PC and might be involved in cachexia. The activin signal might be a novel target for the treatment of PC.

  20. Tissue absence initiates regeneration through follistatin-mediated inhibition of activin signaling.

    Science.gov (United States)

    Gaviño, Michael A; Wenemoser, Danielle; Wang, Irving E; Reddien, Peter W

    2013-09-10

    Regeneration is widespread, but mechanisms that activate regeneration remain mysterious. Planarians are capable of whole-body regeneration and mount distinct molecular responses to wounds that result in tissue absence and those that do not. A major question is how these distinct responses are activated. We describe a follistatin homolog (Smed-follistatin) required for planarian regeneration. Smed-follistatin inhibition blocks responses to tissue absence but does not prevent normal tissue turnover. Two activin homologs (Smed-activin-1 and Smed-activin-2) are required for the Smed-follistatin phenotype. Finally, Smed-follistatin is wound-induced and expressed at higher levels following injuries that cause tissue absence. These data suggest that Smed-follistatin inhibits Smed-Activin proteins to trigger regeneration specifically following injuries involving tissue absence and identify a mechanism critical for regeneration initiation, a process important across the animal kingdom. DOI:http://dx.doi.org/10.7554/eLife.00247.001.

  1. Activin A-Smad Signaling Mediates Connective Tissue Growth Factor Synthesis in Liver Progenitor Cells.

    Science.gov (United States)

    Ding, Ze-Yang; Jin, Guan-Nan; Wang, Wei; Sun, Yi-Min; Chen, Wei-Xun; Chen, Lin; Liang, Hui-Fang; Datta, Pran K; Zhang, Ming-Zhi; Zhang, Bixiang; Chen, Xiao-Ping

    2016-03-22

    Liver progenitor cells (LPCs) are activated in chronic liver damage and may contribute to liver fibrosis. Our previous investigation reported that LPCs produced connective tissue growth factor (CTGF/CCN2), an inducer of liver fibrosis, yet the regulatory mechanism of the production of CTGF/CCN2 in LPCs remains elusive. In this study, we report that Activin A is an inducer of CTGF/CCN2 in LPCs. Here we show that expression of both Activin A and CTGF/CCN2 were upregulated in the cirrhotic liver, and the expression of Activin A positively correlates with that of CTGF/CCN2 in liver tissues. We go on to show that Activin A induced de novo synthesis of CTGF/CCN2 in LPC cell lines LE/6 and WB-F344. Furthermore, Activin A contributed to autonomous production of CTGF/CCN2 in liver progenitor cells (LPCs) via activation of the Smad signaling pathway. Smad2, 3 and 4 were all required for this induction. Collectively, these results provide evidence for the fibrotic role of LPCs in the liver and suggest that the Activin A-Smad-CTGF/CCN2 signaling in LPCs may be a therapeutic target of liver fibrosis.

  2. Direct Effects of Activin A on the Activation of Mouse Macrophage RAW264.7 Cells

    Institute of Scientific and Technical Information of China (English)

    Jingyan Ge; Yinan Wang; Ye Feng; Haiyan Liu; Xueling Cui; Fangfang Chen; Guixiang Tai; Zhonghui Liu

    2009-01-01

    Macrophages play critical roles in innate immune and acquired immune via secreting pro-inflammatory mediators, phagocytosing microorganisms and presenting antigens. Activin A, a member of transforming growth factor β (TGF-β) superfamily, is produced by macrophages and microglia cells. In this study, we reported a direct effect of activin A as a pro-inflammatory factor on mouse macrophage cell line RAW264.7 cells. Our data revealed that activin A could not only increase IL-1v and IL-6 production from RAW264.7 cells, but also promote pinocytic and phagocytic activities of RAW264.7 cells. In addition, activin A obviously up-regulated MHC Ⅱ expression on the surface of RAW264.7 cells, whereas did not influence MHC I expression. Activin A also enhanced CD80 expression, which is a marker of activated macrophages, but did not influence RAW264.7 cell proliferation. These data suggest that activin A may regulate primary macrophage-mediated innate and acquired immune response via promoting the activation of rest macrophages. Cellular & Molecular Immunology.

  3. Activin A induces Langerhans cell differentiation in vitro and in human skin explants.

    Directory of Open Access Journals (Sweden)

    Tiziana Musso

    Full Text Available Langerhans cells (LC represent a well characterized subset of dendritic cells located in the epidermis of skin and mucosae. In vivo, they originate from resident and blood-borne precursors in the presence of keratinocyte-derived TGFbeta. In vitro, LC can be generated from monocytes in the presence of GM-CSF, IL-4 and TGFbeta. However, the signals that induce LC during an inflammatory reaction are not fully investigated. Here we report that Activin A, a TGFbeta family member induced by pro-inflammatory cytokines and involved in skin morphogenesis and wound healing, induces the differentiation of human monocytes into LC in the absence of TGFbeta. Activin A-induced LC are Langerin+, Birbeck granules+, E-cadherin+, CLA+ and CCR6+ and possess typical APC functions. In human skin explants, intradermal injection of Activin A increased the number of CD1a+ and Langerin+ cells in both the epidermis and dermis by promoting the differentiation of resident precursor cells. High levels of Activin A were present in the upper epidermal layers and in the dermis of Lichen Planus biopsies in association with a marked infiltration of CD1a+ and Langerin+ cells. This study reports that Activin A induces the differentiation of circulating CD14+ cells into LC. Since Activin A is abundantly produced during inflammatory conditions which are also characterized by increased numbers of LC, we propose that this cytokine represents a new pathway, alternative to TGFbeta, responsible for LC differentiation during inflammatory/autoimmune conditions.

  4. Substantial Increases Occur in Serum Activins and Follistatin during Lung Transplantation.

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    David M de Kretser

    Full Text Available Lung transplantation exposes the donated lung to a period of anoxia. Re-establishing the circulation after ischemia stimulates inflammation causing organ damage. Since our published data established that activin A is a key pro-inflammatory cytokine, we assessed the roles of activin A and B, and their binding protein, follistatin, in patients undergoing lung transplantation.Sera from 46 patients participating in a published study of remote ischemia conditioning in lung transplantation were used. Serum activin A and B, follistatin and 11 other cytokines were measured in samples taken immediately after anaesthesia induction, after remote ischemia conditioning or sham treatment undertaken just prior to allograft reperfusion and during the subsequent 24 hours.Substantial increases in serum activin A, B and follistatin occurred after the baseline sample, taken before anaesthesia induction and peaked immediately after the remote ischemia conditioning/sham treatment. The levels remained elevated 15 minutes after lung transplantation declining thereafter reaching baseline 2 hours post-transplant. Activin B and follistatin concentrations were lower in patients receiving remote ischemia conditioning compared to sham treated patients but the magnitude of the decrease did not correlate with early transplant outcomes.We propose that the increases in the serum activin A, B and follistatin result from a combination of factors; the acute phase response, the reperfusion response and the use of heparin-based anti-coagulants.

  5. Activin-Like Kinase 2 Functions in Peri-implantation Uterine Signaling in Mice and Humans

    Science.gov (United States)

    Clementi, Caterina; Tripurani, Swamy K.; Large, Michael J.; Edson, Mark A.; Creighton, Chad J.; Hawkins, Shannon M.; Kovanci, Ertug; Kaartinen, Vesa; Lydon, John P.; Pangas, Stephanie A.; DeMayo, Francesco J.; Matzuk, Martin M.

    2013-01-01

    Implantation of a blastocyst in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP) ligands and receptors are expressed in the uterus of pregnant mice, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2), during mouse pregnancy by producing mice carrying a conditional ablation of Alk2 in the uterus (Alk2 cKO mice). In the absence of ALK2, embryos demonstrate delayed invasion into the uterine epithelium and stroma, and upon implantation, stromal cells fail to undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein β (Cebpb) expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of CEBPB in the stroma to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (hESC) and discovered that ablation of ALK2 alters hESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP) analysis of decidualizing hESC confirmed that BMP signaling proteins, SMAD1/5, directly regulate expression of CEBPB by binding a distinct regulatory sequence in the 3′ UTR of this gene; CEBPB, in turn, regulates the expression of progesterone receptor (PGR). Our work clarifies the conserved mechanisms through which BMPs regulate peri-implantation in rodents and primates and, for the first time, uncovers a linear pathway of BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization. PMID:24244176

  6. Uterine Activin-Like Kinase 4 Regulates Trophoblast Development During Mouse Placentation.

    Science.gov (United States)

    Peng, Jia; Fullerton, Paul T; Monsivais, Diana; Clementi, Caterina; Su, Gloria H; Matzuk, Martin M

    2015-12-01

    The placenta is the first organ to develop after fertilization. It forms an interface between the maternal uterus and growing fetus to allow nutrient uptake, waste elimination, and gas exchange for a successful pregnancy in both mice and humans. In the past 2 decades, in vivo and in vitro approaches have been used to show that several members of the TGF-β superfamily regulate embryo implantation and placental development. Nodal, a TGF-β superfamily ligand, is essential for mesendoderm formation and left-right axis patterning during embryogenesis, and Nodal null mutants exhibit abnormal placental organization with expansion of trophoblast giant cells and a decrease of spongiotrophoblast and labyrinth. To better understand the importance of Nodal signaling in the uterus, we established a mouse model to conditionally ablate activin-like kinase 4 (ALK4; the Nodal type 1 receptor) using Cre recombinase driven by the progesterone receptor promoter sequences (Pgr-Cre). Alk4 conditional knockout females are subfertile due to placental abnormalities and fetal loss in pregnancy, with a placental disorganization phenotype similar to what is observed in Nodal null mice. Thus, Nodal likely functions as an indirect regulator of placental development by binding to type 1 and type 2 receptors on maternal decidual cells to stimulate expression of unknown regulators of placental development. Our findings not only describe the generation of a mouse model that enables study of Nodal signaling in placentation but also provides insights into the pathogenesis of pregnancy complications in humans, including spontaneous abortion, preeclampsia, intrauterine growth restriction, and preterm birth.

  7. Activin-like kinase 2 functions in peri-implantation uterine signaling in mice and humans.

    Science.gov (United States)

    Clementi, Caterina; Tripurani, Swamy K; Large, Michael J; Edson, Mark A; Creighton, Chad J; Hawkins, Shannon M; Kovanci, Ertug; Kaartinen, Vesa; Lydon, John P; Pangas, Stephanie A; DeMayo, Francesco J; Matzuk, Martin M

    2013-11-01

    Implantation of a blastocyst in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP) ligands and receptors are expressed in the uterus of pregnant mice, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2), during mouse pregnancy by producing mice carrying a conditional ablation of Alk2 in the uterus (Alk2 cKO mice). In the absence of ALK2, embryos demonstrate delayed invasion into the uterine epithelium and stroma, and upon implantation, stromal cells fail to undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein β (Cebpb) expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of CEBPB in the stroma to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (hESC) and discovered that ablation of ALK2 alters hESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP) analysis of decidualizing hESC confirmed that BMP signaling proteins, SMAD1/5, directly regulate expression of CEBPB by binding a distinct regulatory sequence in the 3' UTR of this gene; CEBPB, in turn, regulates the expression of progesterone receptor (PGR). Our work clarifies the conserved mechanisms through which BMPs regulate peri-implantation in rodents and primates and, for the first time, uncovers a linear pathway of BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization.

  8. Activin-like kinase 2 functions in peri-implantation uterine signaling in mice and humans.

    Directory of Open Access Journals (Sweden)

    Caterina Clementi

    2013-11-01

    Full Text Available Implantation of a blastocyst in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP ligands and receptors are expressed in the uterus of pregnant mice, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2, during mouse pregnancy by producing mice carrying a conditional ablation of Alk2 in the uterus (Alk2 cKO mice. In the absence of ALK2, embryos demonstrate delayed invasion into the uterine epithelium and stroma, and upon implantation, stromal cells fail to undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein β (Cebpb expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of CEBPB in the stroma to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (hESC and discovered that ablation of ALK2 alters hESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP analysis of decidualizing hESC confirmed that BMP signaling proteins, SMAD1/5, directly regulate expression of CEBPB by binding a distinct regulatory sequence in the 3' UTR of this gene; CEBPB, in turn, regulates the expression of progesterone receptor (PGR. Our work clarifies the conserved mechanisms through which BMPs regulate peri-implantation in rodents and primates and, for the first time, uncovers a linear pathway of BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization.

  9. Activin signaling in microsatellite stable colon cancers is disrupted by a combination of genetic and epigenetic mechanisms.

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    Barbara Jung

    Full Text Available BACKGROUND: Activin receptor 2 (ACVR2 is commonly mutated in microsatellite unstable (MSI colon cancers, leading to protein loss, signaling disruption, and larger tumors. Here, we examined activin signaling disruption in microsatellite stable (MSS colon cancers. METHODS: Fifty-one population-based MSS colon cancers were assessed for ACVR1, ACVR2 and pSMAD2 protein. Consensus mutation-prone portions of ACVR2 were sequenced in primary cancers and all exons in colon cancer cell lines. Loss of heterozygosity (LOH was evaluated for ACVR2 and ACVR1, and ACVR2 promoter methylation by methylation-specific PCR and bisulfite sequencing and chromosomal instability (CIN phenotype via fluorescent LOH analysis of 3 duplicate markers. ACVR2 promoter methylation and ACVR2 expression were assessed in colon cancer cell lines via qPCR and IP-Western blots. Re-expression of ACVR2 after demethylation with 5-aza-2'-deoxycytidine (5-Aza was determined. An additional 26 MSS colon cancers were assessed for ACVR2 loss and its mechanism, and ACVR2 loss in all tested cancers correlated with clinicopathological criteria. RESULTS: Of 51 MSS colon tumors, 7 (14% lost ACVR2, 2 (4% ACVR1, and 5 (10% pSMAD2 expression. No somatic ACVR2 mutations were detected. Loss of ACVR2 expression was associated with LOH at ACVR2 (p<0.001 and ACVR2 promoter hypermethylation (p<0.05. ACVR2 LOH, but not promoter hypermethylation, correlated with CIN status. In colon cancer cell lines with fully methylated ACVR2 promoter, loss of ACVR2 mRNA and protein expression was restored with 5-Aza treatment. Loss of ACVR2 was associated with an increase in primary colon cancer volume (p<0.05. CONCLUSIONS: Only a small percentage of MSS colon cancers lose expression of activin signaling members. ACVR2 loss occurs through LOH and ACVR2 promoter hypermethylation, revealing distinct mechanisms for ACVR2 inactivation in both MSI and MSS subtypes of colon cancer.

  10. Regulation of C-cadherin function during activin induced morphogenesis of Xenopus animal caps.

    Science.gov (United States)

    Brieher, W M; Gumbiner, B M

    1994-07-01

    Treatment of Xenopus animal pole tissue with activin results in the induction of mesodermal cell types and a dramatic elongation of the tissue. The morphogenetic movements involved in the elongation appear similar to those in normal gastrulation, which is driven by cell rearrangement and cell intercalations. We have used this system to explore the potential regulation of cell-cell adhesion and cadherin function during morphogenesis. Quantitative blastomere aggregation assays revealed that activin induction reduced the calcium-dependent adhesion between blastomeres. Activin-induced blastomeres formed smaller aggregates, and a greater proportion of the population remained as single cells compared to uninduced blastomeres. The aggregation was mediated by C-cadherin because C-cadherin was present in the blastomeres during the aggregation assay, and monoclonal antibodies against C-cadherin inhibited the calcium-dependent aggregation of blastomeres. E-cadherin was not detectable until after the completion of the assay and, therefore, does not explain the adhesive differences between induced and uninduced blastomeres. L cells stably expressing C-cadherin (LC cells) were used to demonstrate that C-cadherin activity was specifically altered after activin induction. Blastomeres induced with activin bound fewer LC cells than uninduced blastomers. L cells not expressing C-cadherin did not adhere to blastomeres. The changes in C-cadherin-mediated adhesion occurred without detectable changes in the steady-state levels of C-cadherin or the amount of C-cadherin present on the surface of the cell. Immunoprecipitation of C-cadherin and its associated catenins revealed that the ratio of C-cadherin and the catenins was not altered by activin induction. These results demonstrate that activin decreases the adhesive function of existing C-cadherin molecules on the surface of blastomeres and suggest that decreased cadherin mediated cell-cell adhesion is associated with increased

  11. Activin B regulates islet composition and islet mass but not whole body glucose homeostasis or insulin sensitivity

    Science.gov (United States)

    Bonomi, Lara; Brown, Melissa; Ungerleider, Nathan; Muse, Meghan; Matzuk, Martin M.

    2012-01-01

    Based on the phenotype of the activin-like kinase-7 (ALK7)-null mouse, activins A and B have been proposed to play distinct roles in regulating pancreatic islet function and glucose homeostasis, with activin A acting to enhance islet function and insulin release while activin B antagonizes these actions. We therefore hypothesized that islets from activin B-null (BBKO) mice would have enhanced glucose-stimulated insulin secretion. In addition, we hypothesized that this enhanced islet function would translate into increased whole body glucose tolerance. We tested these hypotheses by analyzing glucose homeostasis, insulin secretion, and islet function in BBKO mice. No differences were observed in fasting glucose or insulin levels, glucose tolerance, or insulin sensitivity compared with weight-matched young or older males. Similarly, there were no significant differences in insulin secretion comparing islets from WT or BBKO males at either age. However, BBKO islets were more sensitive to activin A, myostatin (MSTN), and follistatin (FST) treatments, so that activin A and FST inhibited and MSTN enhanced glucose stimulated insulin secretion. While mean islet area and the distribution of islet areas were not different between the genotypes, islet mass, islet number, and the proportion of α-cells/islet were significantly reduced in BBKO islets. These results indicate that activin B does not antagonize activin A to influence whole body glucose homeostasis or β-cell function but does influence islet mass and proportion of α-cells/islet. Therefore, loss of activin B signaling alone does not account for the ALK7-null phenotype, but activin B may have important roles in modulating islet mass, islet number, and the cellular composition of islets. PMID:22739106

  12. Regulation of Muscle Mass by Follistatin and Activins

    Science.gov (United States)

    Lee, Se-Jin; Lee, Yun-Sil; Zimmers, Teresa A.; Soleimani, Arshia; Matzuk, Martin M.; Tsuchida, Kunihiro; Cohn, Ronald D.; Barton, Elisabeth R.

    2010-01-01

    Myostatin is a TGF-β family member that normally acts to limit skeletal muscle mass. Follistatin is a myostatin-binding protein that can inhibit myostatin activity in vitro and promote muscle growth in vivo. Mice homozygous for a mutation in the Fst gene have been shown to die immediately after birth but have a reduced amount of muscle tissue, consistent with a role for follistatin in regulating myogenesis. Here, we show that Fst mutant mice exhibit haploinsufficiency, with muscles of Fst heterozygotes having significantly reduced size, a shift toward more oxidative fiber types, an impairment of muscle remodeling in response to cardiotoxin-induced injury, and a reduction in tetanic force production yet a maintenance of specific force. We show that the effect of heterozygous loss of Fst is at least partially retained in a Mstn-null background, implying that follistatin normally acts to inhibit other TGF-β family members in addition to myostatin to regulate muscle size. Finally, we present genetic evidence suggesting that activin A may be one of the ligands that is regulated by follistatin and that functions with myostatin to limit muscle mass. These findings potentially have important implications with respect to the development of therapeutics targeting this signaling pathway to preserve muscle mass and prevent muscle atrophy in a variety of inherited and acquired forms of muscle degeneration. PMID:20810712

  13. Activin Bioactivity Affects Germ Cell Differentiation in the Postnatal Mouse Testis In Vivo1

    Science.gov (United States)

    Mithraprabhu, Sridurga; Mendis, Sirisha; Meachem, Sarah J.; Tubino, Laura; Matzuk, Martin M.; Brown, Chester W.; Loveland, Kate L.

    2010-01-01

    The transforming growth factor beta superfamily ligand activin A controls juvenile testis growth by stimulating Sertoli cell proliferation. Testicular levels are highest in the first postnatal week, when Sertoli cells are proliferating and spermatogonial stem cells first form. Levels decrease sharply as Sertoli cell proliferation ceases and spermatogenic differentiation begins. We hypothesized that changing activin levels also affect germ cell maturation. We detected an acute and developmentally regulated impact of activin on Kit mRNA in cocultures of Sertoli cells and germ cells from Day 8, but not Day 4, mice. Both stereological and flow cytometry analyses identified an elevated spermatogonium:Sertoli cell ratio in Day 7 testes from InhbaBK/BK mice, which have decreased bioactive activin, and the germ cell markers Sycp3, Dazl, and Ccnd3 were significantly elevated in InhbaBK/BK mice. The flow cytometry measurements demonstrated that surface KIT protein is significantly higher in Day 7 InhbaBK/BK germ cells than in wild-type littermates. By Day 14, the germ cell:Sertoli cell ratio did not differ between genotypes, but the transition of type A spermatogonia into spermatocytes was altered in InhbaBK/BK testes. We conclude that regulated activin signaling not only controls Sertoli cell proliferation, as previously described, but also influences the in vivo progression of germ cell maturation in the juvenile testis at the onset of spermatogenesis. PMID:20130270

  14. Activin A suppressed hepatic oval cell-mediated liver regeneration in vivo%Activin A抑制卵圆细胞介导肝再生的体内研究

    Institute of Scientific and Technical Information of China (English)

    陈琳; 周巧丹; 丁则阳; 张伟; 张必翔; 梁慧芳; 陈孝平

    2012-01-01

    Objective To study the inhibitory effect and mechanism of Activin A on hepatic oval cell-mediated liver regeneratioa Methods 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH) o-val cell-mediated liver regeneration model was established. One μg Activin A (Activin A group) or normal saline (control S group) was infused into portal vein immediately after 70 % partial hepatectomy. Animals were sacrificed at 2nd, 4th, 6th, and 9th day after hepatectomy. Liver regeneration rate was measured. Changes in Pan-CK positive oval cell number and nuclear bromodeoxyuridine labeling were detected by using immunohistochemistry. The expression of phosphorylated smad2, p15, and p21 were detected by using Western blotting. Results As compared with control group, the Pan-CK positive number was significantly reduced in Activin A group at 6th and 9th day after hepatectomy,and Brdu labeling nuclear number was reduced in Activin A group at 4th,6th and 9th day after hepatectomy. The liver regeneration rate in Activin A group was lower than in control group. Higher levels of phosphorylated smad2,p15 and p21 were detected in Activin A group. Conclusion Activin A could suppress o-val cell-mediated liver regeneration through smad pathway-dependent up-regulation of p15 and p21.%目的 研究Activin A对卵圆细胞介导肝再生的抑制作用及其机制.方法 建立2-乙酰胺基芴/部分肝切除卵圆细胞介导肝再生模型,肝切除后立即经门静脉注射1 μg Activin A(Activin A组),或生理盐水(对照组).肝切除后不同时间点取肝脏标本检测卵圆细胞增殖及肝再生率和磷酸化smad2,p15和p21的表达.结果 Activin A组肝脏中卵圆细胞的增殖及肝再生率均明显低于对照组;Activin A组肝脏中smad2的磷酸化水平及p15,p21的表达水平均高于对照组.结论 Activin A可以通过smad信号通路抑制卵圆细胞介导的肝再生.

  15. Emodin prevents hypoxic-ischemic neuronal injury Involvement of the activin A pathway

    Institute of Scientific and Technical Information of China (English)

    Hongliang Guo; Xiaoran Shen; Ye Xu; Junliang Yuan; Dongming Zhao; Wenli Hu

    2013-01-01

    Emodin, an extract of dried rhizomes and the root of the Rhizoma Polygoni Cuspidati, can protect neurons from hypoxic-ischemic brain damage. This study aimed to verify the underlying mechanism. After PC12 cells had differentiated into neuron-like cells under the induction of mouse nerve growth factor, cells were subjected to oxygen-glucose deprivation and treated with emodin. Results showed that the viability of neuron-like cells cultured under an ischemia-hypoxia environment decreased, while the expression of activin A and caspase-3 in cells increased. Emodin raised the survival rate of oxygen-glucose deprived neuron-like cells, increased activin A expression, and decreased caspase-3 expression. Experimental findings indicate that emodin can inhibit neuronal apoptosis and alleviate the injury of nerve cells after oxygen-glucose deprivation through the activin A pathway.

  16. Activin and GDF11 collaborate in feedback control of neuroepithelial stem cell proliferation and fate

    Science.gov (United States)

    Gokoffski, Kimberly K.; Wu, Hsiao-Huei; Beites, Crestina L.; Kim, Joon; Kim, Euiseok J.; Matzuk, Martin M.; Johnson, Jane E.; Lander, Arthur D.; Calof, Anne L.

    2011-01-01

    Studies of the olfactory epithelium model system have demonstrated that production of neurons is regulated by negative feedback. Previously, we showed that a locally produced signal, the TGFβ superfamily ligand GDF11, regulates the genesis of olfactory receptor neurons by inhibiting proliferation of the immediate neuronal precursors (INPs) that give rise to them. GDF11 is antagonized by follistatin (FST), which is also produced locally. Here, we show that Fst–/– mice exhibit dramatically decreased neurogenesis, a phenotype that can only be partially explained by increased GDF11 activity. Instead, a second FST-binding factor, activin βB (ACTβB), inhibits neurogenesis by a distinct mechanism: whereas GDF11 inhibits expansion of INPs, ACTβB inhibits expansion of stem and early progenitor cells. We present data supporting the concept that these latter cells, previously considered two distinct types, constitute a dynamic stem/progenitor population in which individual cells alternate expression of Sox2 and/or Ascl1. In addition, we demonstrate that interplay between ACTβB and GDF11 determines whether stem/progenitor cells adopt a glial versus neuronal fate. Altogether, the data indicate that the transition between stem cells and committed progenitors is neither sharp nor irreversible and that GDF11, ACTβB and FST are crucial components of a circuit that controls both total cell number and the ratio of neuronal versus glial cells in this system. Thus, our findings demonstrate a close connection between the signals involved in the control of tissue size and those that regulate the proportions of different cell types. PMID:21852401

  17. Diagnostic accuracy of serum activin A in detection of ectopic pregnancy

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    Mohammad Ali Roghaei

    2012-01-01

    Full Text Available Background: Ectopic pregnancy (EP still remains a main cause of maternal mortalities. This study is designed to evaluate the accuracy of serum Activin A in detection of ectopic pregnancy. Methods : This prospective observational study was conducted from 2009 to 2010 at two main referral university hospitals, Isfahan University of Medical Sciences, Isfahan, Iran. Two hundred subjects who were under 10 week′s pregnancy with clinical presentations of abdominal pain and vaginal bleeding were enrolled. After sampling serum Activin A, patients underwent ultrasonography, titer of B-HCG and surgery (if indicated and were divided into two groups: EP (n = 100 and intrauterine pregnancy (IUP (n = 100. The mean of Activin A was compared between groups and by ROC curve, the optimal cut off with sensitivity, specificity, positive predictive value (PPV and negative predictive value (NPV were determined. Results : The mean age of women with IUP was 25.4 ± 4.3 years (15-40 years compared with 25.9 ± 4.1 years in women in EP group (P = 0.448. Statistical difference was not found between EP versus IUP groups in gestational age (6.32 ± 1.03 vs. 6.85 ± 1.82 weeks, P = 0.124. The mean of serum Activin A in EP group was 0.264 ± 0.0703 ng/ml versus 0.949 ± 0.5283 ng/ml in IUP group (P < 0.05. According to ROC curve (area under the curve = 0.981, P < 0.05, confidence interval: 0.961-1.000, the optimal cut off was estimated as 0.504 ng/ml with sensitivity of 97% and specificity of 93.5%. Conclusion : This study indicated that the mean of serum Activin A is lower in EP compared with IUP. The serum Activin A has a fair accuracy in detecting EP.

  18. Effects of the Activin A–Follistatin System on Myocardial Cell Apoptosis through the Endoplasmic Reticulum Stress Pathway in Heart Failure

    Science.gov (United States)

    Liu, Miao; Mao, Cuiying; Li, Jiayu; Han, Fanglei; Yang, Ping

    2017-01-01

    Background: A previous study suggested that activin A inhibited myocardial cell apoptosis. This study thus aimed to explore the effects of the activin A–follistatin system on myocardial cell apoptosis in heart failure (HF) rats in order to determine whether or not the mechanism operates through the endoplasmic reticulum stress (ERS) pathway. Methods: Myocardial infarction (MI) by vascular deprivation was used to induce HF. The enzyme-linked immunosorbent assay was used to detect activin A, follistatin and brain natriuretic peptide (BNP) contents in serum. Immunohistochemical staining for activin A, follistatin, CCAAT-enhancer-binding protein (C/EBP) homologous protein (CHOP) and caspase-3 was performed on the myocardial tissue. The activin A-stimulated apoptosis of H9c2 cells was tested by flow cytometry. Western blot was used to detect the expression levels of activin A, follistatin and ERS-related proteins. Results: It was found that the high expression of activin A could cause activin A–follistatin system imbalance, inducing myocardial cell apoptosis via ERS in vivo. When HF developed to a certain stage, the expression of follistatin was upregulated to antagonize the expression of activin A. Activin A inhibited cardiomyocyte apoptosis with a low concentration and promoted apoptosis with a high concentration in vitro, also via ERS. Conclusion: Activin A–follistatin system participated in ERS-mediated myocardial cell apoptosis in HF. PMID:28208629

  19. The syndrome of central hypothyroidism and macroorchidism: IGSF1 controls TRHR and FSHB expression by differential modulation of pituitary TGFβ and Activin pathways

    Science.gov (United States)

    García, Marta; Barrio, Raquel; García-Lavandeira, Montserrat; Garcia-Rendueles, Angela R.; Escudero, Adela; Díaz-Rodríguez, Esther; Gorbenko Del Blanco, Darya; Fernández, Ana; de Rijke, Yolanda B.; Vallespín, Elena; Nevado, Julián; Lapunzina, Pablo; Matre, Vilborg; Hinkle, Patricia M.; Hokken-Koelega, Anita C. S.; de Miguel, María P.; Cameselle-Teijeiro, José Manuel; Nistal, Manuel; Alvarez, Clara V.; Moreno, José C.

    2017-01-01

    IGSF1 (Immunoglobulin Superfamily 1) gene defects cause central hypothyroidism and macroorchidism. However, the pathogenic mechanisms of the disease remain unclear. Based on a patient with a full deletion of IGSF1 clinically followed from neonate to adulthood, we investigated a common pituitary origin for hypothyroidism and macroorchidism, and the role of IGSF1 as regulator of pituitary hormone secretion. The patient showed congenital central hypothyroidism with reduced TSH biopotency, over-secretion of FSH at neonatal minipuberty and macroorchidism from 3 years of age. His markedly elevated inhibin B was unable to inhibit FSH secretion, indicating a status of pituitary inhibin B resistance. We show here that IGSF1 is expressed both in thyrotropes and gonadotropes of the pituitary and in Leydig and germ cells in the testes, but at very low levels in Sertoli cells. Furthermore, IGSF1 stimulates transcription of the thyrotropin-releasing hormone receptor (TRHR) by negative modulation of the TGFβ1-Smad signaling pathway, and enhances the synthesis and biopotency of TSH, the hormone secreted by thyrotropes. By contrast, IGSF1 strongly down-regulates the activin-Smad pathway, leading to reduced expression of FSHB, the hormone secreted by gonadotropes. In conclusion, two relevant molecular mechanisms linked to central hypothyroidism and macroorchidism in IGSF1 deficiency are identified, revealing IGSF1 as an important regulator of TGFβ/Activin pathways in the pituitary. PMID:28262687

  20. [Molecular cloning of the DNA sequence of activin beta A subunit gene mature peptides from panda and related species and its application in the research of phylogeny and taxonomy].

    Science.gov (United States)

    Wang, Xiao-Jing; Wang, Xiao-Xing; Wang, Ya-Jun; Wang, Xi-Zhong; He, Guang-Xin; Chen, Hong-Wei; Fei, Li-Song

    2002-09-01

    Activin, which is included in the transforming growth factor-beta (TGF beta) superfamily of proteins and receptors, is known to have broad-ranging effects in the creatures. The mature peptide of beta A subunit of this gene, one of the most highly conserved sequence, can elevate the basal secretion of follicle-stimulating hormone (FSH) in the pituitary and FSH is pivotal to organism's reproduction. Reproduction block is one of the main reasons which cause giant panda to extinct. The sequence of Activin beta A subunit gene mature peptides has been successfully amplified from giant panda, red panda and malayan sun bear's genomic DNA by using polymerase chain reaction (PCR) with a pair of degenerate primers. The PCR products were cloned into the vector pBlueScript+ of Esherichia coli. Sequence analysis of Activin beta A subunit gene mature peptides shows that the length of this gene segment is the same (359 bp) and there is no intron in all three species. The sequence encodes a peptide of 119 amino acid residues. The homology comparison demonstrates 93.9% DNA homology and 99% homology in amino acid among these three species. Both GenBank blast search result and restriction enzyme map reveal that the sequences of Activin beta A subunit gene mature peptides of different species are highly conserved during the evolution process. Phylogeny analysis is performed with PHYLIP software package. A consistent phylogeny tree has been drawn with three different methods. The software analysis outcome accords with the academic view that giant panda has a closer relationship to the malayan sun bear than the red panda. Giant panda should be grouped into the bear family (Uersidae) with the malayan sun bear. As to the red panda, it would be better that this animal be grouped into the unique family (red panda family) because of great difference between the red panda and the bears (Uersidae).

  1. 1α,25-dihydroxyvitamin D3 stimulates activin A production to fine-tune osteoblast-induced mineralization.

    Science.gov (United States)

    Woeckel, V J; van der Eerden, B C J; Schreuders-Koedam, M; Eijken, M; Van Leeuwen, J P T M

    2013-11-01

    In healthy bones, mineralization has to be tightly controlled to avoid pathological phenotypes. In this study, we investigated interactions between 1α,25(OH)2 D3 (1,25D3) and activin A in the regulation of osteoblast induced mineralization. In human osteoblast cultures, we demonstrated that besides stimulation of mineralization, 1,25D3 also induced activin A, a strong inhibitor of mineralization. Simultaneously, follistatin (FST), the natural antagonist of activin A, was down-regulated by1,25D3. This resulted in an increase in activin A activity during 1,25D3 treatment. We also showed that in 1,25D3-treated osteoblasts, mineralization can be further increased when activin A activity was abrogated by adding exogenous FST. This observation implies that, besides stimulation of mineralization, 1,25D3 also controls activin A-mediated inhibition of mineralization. Besides activin A, 1,25D3 also induces osteocalcin (BGLAP), another inhibitor of mineralization. Warfarin, which has been shown to inactivate osteocalcin, increased 1,25D3-induced mineralization. Interaction between these two systems became evident from the synergistic increase in BGLAP expression upon blocking activin activity in 1,25D3-treated cultures. In conclusion, we demonstrate that 1,25D3 stimulation of mineralization by human osteoblasts is suppressed by concomitant induction of inhibitors of mineralization. Mineralization induction by 1,25D3 may actually be controlled via interplay with activin A and osteocalcin. Finally, this complex regulation of mineralization substantiates the significance of tight control of mineralization to prevent excessive mineralization and consequently reduction in bone quality and strength.

  2. Serum activin A and follistatin levels in gestational diabetes and the association of the Activin A-Follistatin system with anthropometric parameters in offspring.

    Directory of Open Access Journals (Sweden)

    Silvia Näf

    Full Text Available CONTEXT: The Activin A-Follistatin system has emerged as an important regulator of lipid and glucose metabolism with possible repercussions on fetal growth. OBJECTIVE: To analyze circulating activin A, follistatin and follistatin-like-3 (FSTL3 levels and their relationship with glucose metabolism in pregnant women and their influence on fetal growth and neonatal adiposity. DESIGN AND METHODS: A prospective cohort was studied comprising 207 pregnant women, 129 with normal glucose tolerance (NGT and 78 with gestational diabetes mellitus (GDM and their offspring. Activin A, follistatin and FSTL3 levels were measured in maternal serum collected in the early third trimester of pregnancy. Serial fetal ultrasounds were performed during the third trimester to evaluate fetal growth. Neonatal anthropometry was measured to assess neonatal adiposity. RESULTS: Serum follistatin levels were significantly lower in GDM than in NGT pregnant women (8.21±2.32 ng/mL vs 9.22±3.41, P = 0.012 whereas serum FSTL3 and activin A levels were comparable between the two groups. Serum follistatin concentrations were negatively correlated with HOMA-IR and positively with ultrasound growth parameters such as fractional thigh volume estimation in the middle of the third trimester and percent fat mass at birth. Also, in the stepwise multiple linear regression analysis serum follistatin levels were negatively associated with HOMA-IR (β = -0.199, P = 0.008 and the diagnosis of gestational diabetes (β = -0.138, P = 0.049. Likewise, fractional thigh volume estimation in the middle of third trimester and percent fat mass at birth were positively determined by serum follistatin levels (β = 0.214, P = 0.005 and β = 0.231, P = 0.002, respectively. CONCLUSIONS: Circulating follistatin levels are reduced in GDM compared with NGT pregnant women and they are positively associated with fetal growth and neonatal adiposity. These data suggest a role of

  3. Crosstalk between the Smad and the Mitogen-Activated Protein Kinase Pathways is Essential for Erythroid Differentiation of Erythroleukemia Cells Induced by TGF-β, Activin, Hydroxyurea and Butyrate.

    Science.gov (United States)

    Akel, Salem; Bertolette, Daniel; Ruscetti, Francis W

    2013-04-22

    The role of crosstalk between the Smad and the MAPK signaling pathways in activin-, transforming growth factor-β (TGF-β)-, hydroxyurea (HU) - and butyrate-dependent erythroid differentiation of K562 leukemic cells was studied. Treatment with all four inducers caused transient phosphorylation of Smad2/3 and MAPK proteins including ERK, p38 and JNK. Use of specific inhibitors of p38, ERK and JNK MAPK proteins, and TGF-β type I receptor indicated that differentiation induced by each of these agents involves activation of Smad2/3 and p38 MAPK, and inhibition of ERK MAPK. Also, treatment of cells with an inhibitor of protein serine/threonine phosphatase, okadaic acid (OA), induced phosphorylation of Smad2/3, and p38 MAPK, coincident with its induction of erythroid differentiation. Specific inhibition of TGF-β type I receptor kinase activity not only abolished TGF-β/activin effects but also prevented Smad2/3 activation and erythroid differentiation induced by OA, HU and butyrate. The TGF-β type I receptor kinase inhibitor blocked OA-induced differentiation but not p38 MAPK phosphorylation demonstrating that signals from both pathways are needed. As previously observed, addition of ERK1/2 MAPK inhibitors upregulated Smad2/3 phosphorylation and enhanced differentiation, but these effects were dependent on signals from the TGF-β type I receptor. These data indicate that activation of both Smad2/3 and p38 MAPK signaling pathways is a prerequisite to induce erythroid differentiation of erythroleukemia cells by activin, TGF-β, HU, OA and butyrate.

  4. Regulation of C-cadherin function during activin induced morphogenesis of Xenopus animal caps

    OpenAIRE

    1994-01-01

    Treatment of Xenopus animal pole tissue with activin results in the induction of mesodermal cell types and a dramatic elongation of the tissue. The morphogenetic movements involved in the elongation appear similar to those in normal gastrulation, which is driven by cell rearrangement and cell intercalations. We have used this system to explore the potential regulation of cell-cell adhesion and cadherin function during morphogenesis. Quantitative blastomere aggregation assays revealed that act...

  5. ACVR2A promoter polymorphism rs1424954 in the Activin-A signaling pathway in trophoblasts.

    Science.gov (United States)

    Thulluru, H K; Michel, O J; Oudejans, C B M; van Dijk, M

    2015-04-01

    Pre-eclampsia is a pregnancy-specific disorder and characterized by reduced trophoblast invasion and reduced spiral artery remodeling in the first trimester placenta. A polymorphism located in the promoter region of ACVR2A (rs1424954 (A > G)) has previously been shown to be significantly associated with pre-eclampsia. The effects of this variant on ACVR2A expression and its function in the Activin-A signaling pathway were studied by transfections in SGHPL-5 extravillous trophoblasts followed by qRT-PCR. Here we show that the ACVR2A promoter susceptibility variant causes a downregulation of ACVR2A expression. We also provide evidence for transcription of a so-called PROMPT (PROMoter-uPstream-Transcript) in the opposite direction of ACVR2A, containing the polymorphism, and downregulated when the susceptibility allele is carried, which either shares the same promoter as ACVR2A or is a non-coding RNA that is able to enhance ACVR2A transcription. Furthermore, when the effect of the susceptibility variant is mimicked by knockdown of ACVR2A, physiologic concentrations of Activin-A cause a reduction in NODAL mRNA expression in the SGHPL-5 trophoblasts, indicative of a protective effect as reduction in NODAL expression is associated with an increase in trophoblast invasion. However, at pathologic levels of Activin-A, as found in pre-eclampsia, this effect is no longer seen, and we show this is potentially caused by a lack of downregulation of ACVR2B. The combined data suggest a double hit phenomenon in which the first hit, the promoter variant, together with the second hit, pathological levels of Activin-A, lead to high levels of NODAL, associated with reduced trophoblast invasion and observed in pre-eclamptic placentas. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Activin and Bmp4 Signaling Converge on Wnt Activation during Odontogenesis.

    Science.gov (United States)

    Kwon, H-J E; Jia, S; Lan, Y; Liu, H; Jiang, R

    2017-09-01

    Previous studies show that both activin and Bmp4 act as crucial mesenchymal odontogenic signals during early tooth development. Remarkably, mice lacking activin-βA ( Inhba(-/-)) and mice with neural crest-specific inactivation of Bmp4 ( Bmp4(ncko/ncko)) both exhibit bud-stage developmental arrest of the mandibular molar tooth germs while their maxillary molar tooth germs completed morphogenesis. In this study, we found that, whereas expression of Inhba and Bmp4 in the developing tooth mesenchyme is independent of each other, Bmp4(ncko/ncko)Inhba(-/-) compound mutant mice exhibit early developmental arrest of all tooth germs. Moreover, genetic inactivation of Osr2, a negative regulator of the odontogenic function of the Bmp4-Msx1 signaling pathway, rescues mandibular molar morphogenesis in Inhba(-/-) embryos. We recently reported that Osr2 and the Bmp4-Msx1 pathway control the bud-to-cap transition of tooth morphogenesis through antagonistic regulation of expression of secreted Wnt antagonists, including Dkk2 and Sfrp2, in the developing tooth mesenchyme. We show here that expression of Dkk2 messenger RNAs was significantly upregulated and expanded into the tooth bud mesenchyme in Inhba(-/-) embryos in comparison with wild-type littermates. Furthermore, in utero treatment with either lithium chloride, an agonist of canonical Wnt signaling, or the DKK inhibitor IIIC3a rescued mandibular molar tooth morphogenesis in Inhba(-/-) embryos. Together with our finding that the developing mandibular molar tooth bud mesenchyme expresses significantly higher levels of Dkk2 than the developing maxillary molar tooth mesenchyme, these data indicate that Bmp4 and activin signaling pathways converge on activation of the Wnt signaling pathway to promote tooth morphogenesis through the bud-to-cap transition and that the differential effects of loss of activin or Bmp4 signaling on maxillary and mandibular molar tooth morphogenesis are mainly due to the differential expression of Wnt

  7. Role of Activin-A and Myostatin and Their Signaling Pathway in Human Myometrial and Leiomyoma Cell Function

    Science.gov (United States)

    Islam, Md Soriful; Catherino, William H.; Protic, Olga; Janjusevic, Milijana; Gray, Peter Clarke; Giannubilo, Stefano Raffaele; Ciavattini, Andrea; Lamanna, Pasquale; Tranquilli, Andrea Luigi; Petraglia, Felice

    2014-01-01

    Context: Uterine leiomyomas are highly prevalent benign tumors of premenopausal women and the most common indication for hysterectomy. However, the exact etiology of this tumor is not fully understood. Objective: The objective of the study was to evaluate the role of activin-A and myostatin and their signaling pathways in human myometrial and leiomyoma cells. Design: This was a laboratory study. Setting: Myometrial and leiomyoma cells (primary and cell lines) were cultured in vitro. Patients: The study included premenopausal women who were admitted to the hospital for myomectomy or hysterectomy. Interventions: Primary myometrial and leiomyoma cells and/or cell lines were treated with activin-A (4 nM) and myostatin (4 nM) for different days of interval (to measure proliferation rate) or 30 minutes (to measure signaling molecules) or 48 hours to measure proliferating markers, extracellular matrix mRNA, and/or protein expression by real-time PCR, Western blot, and/or immunocytochemistry. Results: We found that activin-A and myostatin significantly reduce cell proliferation in primary myometrial cells but not in leiomyoma cells as measured by a CyQUANT cell proliferation assay kit. Reduced expression of proliferating cell nuclear antigen and Ki-67 were also observed in myometrial cells in response to activin-A and myostatin treatment. Activin-A also significantly increased mRNA expression of fibronectin, collagen1A1, and versican in primary leiomyoma cells. Finally, we found that activin-A and myostatin activate Smad-2/3 signaling but do not affect ERK or p38 signaling in both myometrial and leiomyoma cells. Conclusions: This study results suggest that activin-A and myostatin can exert antiproliferative and/or fibrotic effects on these cell types via Smad-2/3 signaling. PMID:24606069

  8. Activin-A and Myostatin Response and Steroid Regulation in Human Myometrium: Disruption of Their Signalling in Uterine Fibroid

    Science.gov (United States)

    Bloise, Enrrico; Gray, Peter C.; Carrarelli, Patrizia; Islam, Md. Soriful; De Pascalis, Flavio; Severi, Filiberto Maria; Vale, Wylie; Castellucci, Mario; Petraglia, Felice

    2011-01-01

    Context: Investigation of activin-A (A) and myostatin (M) in human myometrium (HM) and leiomyoma (HL) will explain their involvement in human myometrial pathophysiology. Objective: We aimed to investigate A and M response and steroid regulation in HM. We also evaluated A and M expression and response in HL. Design: Tissues were analyzed and cultured. Patients: Patients included fertile (in proliferative phase) and menopausal women undergoing hysterectomy. Interventions: HM explant cultures were treated with A and M (for Smad-7 mRNA quantification) or estrogen and progesterone (for A and M mRNA quantification). A and M expression levels were also evaluated in menopausal (physiological absence of steroids) HM specimens. A and M and their receptors were evaluated in HL (n = 8, diameter 5–8 cm) compared with their matched HM. HL explants cultures were treated with A and M (for Smad7 mRNA quantification), and, to explain the absence of response, the levels of follistatin, follistatin-related gene (FLRG), and Cripto were evaluated. Results: A and M increased Smad7 expression in HM explants. A and M mRNAs were both reduced after estradiol treatment, unchanged after progesterone treatment, but were higher in menopausal than fertile (in proliferative phase) specimens. A, M, and FLRG were expressed at higher levels in HL compared with adjacent HM, whereas the receptors, follistatin, and Smad7 mRNAs resulted unchanged. Cripto mRNA was expressed only in HL. Conclusions: A and M act on human HM and are regulated by steroids. In HL there is an increase of A, M, FLRG, and Cripto expression. PMID:21177794

  9. A novel member of the transmembrane serine/threonine kinase receptor family is specifically expressed in the gonads and in mesenchymal cells adjacent to the mullerian duct

    NARCIS (Netherlands)

    W.M. Baarends (Willy); M.J. van Helmond (Marjolein); M. Verhoef-Post (Miriam); P.J.C.M. van der Schoot; J.W. Hoogerbrugge (Jos); J.P. de Winter (Johan); J.Th.J. Uilenbroek (Jan); B. Karels (Bas)

    1994-01-01

    textabstractThe activin and TGF-beta type II receptors are members of a separate subfamily of transmembrane receptors with intrinsic protein kinase activity, which also includes the recently cloned TGF-beta type I receptor. We have isolated and characterized a cDNA clon

  10. Activin/Nodal signaling controls divergent transcriptional networks in human embryonic stem cells and in endoderm progenitors.

    Science.gov (United States)

    Brown, Stephanie; Teo, Adrian; Pauklin, Siim; Hannan, Nicholas; Cho, Candy H-H; Lim, Bing; Vardy, Leah; Dunn, N Ray; Trotter, Matthew; Pedersen, Roger; Vallier, Ludovic

    2011-08-01

    Activin/Nodal signaling is necessary to maintain pluripotency of human embryonic stem cells (hESCs) and to induce their differentiation toward endoderm. However, the mechanisms by which Activin/Nodal signaling achieves these opposite functions remain unclear. To unravel these mechanisms, we examined the transcriptional network controlled in hESCs by Smad2 and Smad3, which represent the direct effectors of Activin/Nodal signaling. These analyses reveal that Smad2/3 participate in the control of the core transcriptional network characterizing pluripotency, which includes Oct-4, Nanog, FoxD3, Dppa4, Tert, Myc, and UTF1. In addition, similar experiments performed on endoderm cells confirm that a broad part of the transcriptional network directing differentiation is downstream of Smad2/3. Therefore, Activin/Nodal signaling appears to control divergent transcriptional networks in hESCs and in endoderm. Importantly, we observed an overlap between the transcriptional network downstream of Nanog and Smad2/3 in hESCs; whereas, functional studies showed that both factors cooperate to control the expression of pluripotency genes. Therefore, the effect of Activin/Nodal signaling on pluripotency and differentiation could be dictated by tissue specific Smad2/3 partners such as Nanog, explaining the mechanisms by which signaling pathways can orchestrate divergent cell fate decisions.

  11. Placental activin A is required for follicular development during the second half of pregnancy in the golden hamster (Mesocricetus auratus).

    Science.gov (United States)

    Furuta, Chie; Arakawa, Sayoko; Shi, Zhanquan; Watanabe, Gen; Taya, Kazuyoshi

    2008-04-01

    Numerous antral follicles develop during the second half of pregnancy in the golden hamster even though LH and FSH are maintained at basal levels. To investigate the possible hormone actions of activin A associated with follicular development, pregnant golden hamsters were placentectomized on day 6 of pregnancy and animals were sacrificed at day 8, 10, 12, or 14 of pregnancy. There was a drastic decrease in the plasma concentrations of activin A from day 10 of pregnancy in the operated group compared to the controls. Positive immunohistochemical staining of inhibin/activin subunits betaA and betaB in the syncytiotrophoblast of the placenta revealed the source of activin A, AB, or B. The number of healthy follicles did not change until day 12 between the operated and the control groups, but decreased in numbers in the operated groups thereafter. The decreased concentrations of inhibin A, B, and estradiol-17beta in the operated groups at day 10 and 12 correlated well with the number of mature follicles in response to hCG treatment. In conclusion, we revealed that activin A secreted from the placenta induces folliculogenesis to maintain the high levels of estradiol-17beta needed to induce uterine dilatation for fetus growth and impending parturition.

  12. Serum levels of activin A and inhibin A are not related to the increased susceptibility to pre-eclampsia in type I diabetic pregnancies

    DEFF Research Database (Denmark)

    Ekbom, Pia; Damm, Peter; Andersson, Anna-Maria;

    2006-01-01

    Activin A and inhibin A have been found to be elevated in women without diabetes subsequently developing pre-eclampsia. The aim was to investigate whether activin A and inhibin A in serum were elevated in type I diabetic women after developing pre-eclampsia and, if so, were they clinically useful...

  13. Serum levels of activin A and inhibin A are not related to the increased susceptibility to pre-eclampsia in type I diabetic pregnancies

    DEFF Research Database (Denmark)

    Ekbom, Pia; Damm, Peter; Andersson, Anna-Maria;

    2006-01-01

    Activin A and inhibin A have been found to be elevated in women without diabetes subsequently developing pre-eclampsia. The aim was to investigate whether activin A and inhibin A in serum were elevated in type I diabetic women after developing pre-eclampsia and, if so, were they clinically useful...... as predictors of pre-eclampsia....

  14. Analysis of activin/TGFB-signaling modulators within the normal and dysfunctional adult human testis reveals evidence of altered signaling capacity in a subset of seminomas

    DEFF Research Database (Denmark)

    Dias, Vinali L; Rajpert-De Meyts, Ewa; McLachlan, Robert

    2009-01-01

    Activin is a pleiotropic growth factor belonging to the transforming growth factor-beta (TGFB) superfamily of signaling molecules. Regulated activin signaling is known to influence several steps in rodent male gamete differentiation. TGFB ligand isoforms, TGFB1-B3, also influence germ cell survival...

  15. Changes in the reproductive function and developmental phenotypes in mice following intramuscular injection of an activin betaA-expressing plasmid.

    Science.gov (United States)

    Kim, Mi-Nyeu; Park, Moon Nyeo; Jung, Hoi Kyung; Cho, Chunghee; Mayo, Kelly E; Cho, Byung-Nam

    2008-12-16

    The TGF-beta family protein activin has numerous reported activities with some uncertainty in the reproductive axis and development. The precise roles of activin in in vivo system were investigated using a transient gain of function model. To this end, an expression plasmid, pCMV-rAct, with the activin betaA cDNA fused to the cytomegalovirus promoter, was introduced into muscle of the female adult mice by direct injection. Activin betaA mRNA was detected in the muscle by RT-PCR and subsequent Southern blot analysis. Activin betaA was also detected, and western blot analysis revealed a relatively high level of serum activin with correspondingly increased FSH. In the pCMV-rAct-injected female mice, estrus stage within the estrous cycle was extended. Moreover, increased numbers of corpora lutea and a thickened granulosa cell layer with a small antrum in tertiary follicles within the ovary were observed. When injected female mice were mated with males of proven fertility, a subset of embryos died in utero, and most of those that survived exhibited increased body weight. Taken together, our data reveal that activin betaA can directly influence the estrous cycle, an integral part of the reproduction in female mice and activin betaA can also influence the embryo development as an endocrine fashion.

  16. Changes in the reproductive function and developmental phenotypes in mice following intramuscular injection of an activin betaA-expressing plasmid

    Directory of Open Access Journals (Sweden)

    Mayo Kelly E

    2008-12-01

    Full Text Available Abstract Background The TGF-beta family protein activin has numerous reported activities with some uncertainty in the reproductive axis and development. The precise roles of activin in in vivo system were investigated using a transient gain of function model. Methods To this end, an expression plasmid, pCMV-rAct, with the activin betaA cDNA fused to the cytomegalovirus promoter, was introduced into muscle of the female adult mice by direct injection. Results Activin betaA mRNA was detected in the muscle by RT-PCR and subsequent Southern blot analysis. Activin betaA was also detected, and western blot analysis revealed a relatively high level of serum activin with correspondingly increased FSH. In the pCMV-rAct-injected female mice, estrus stage within the estrous cycle was extended. Moreover, increased numbers of corpora lutea and a thickened granulosa cell layer with a small antrum in tertiary follicles within the ovary were observed. When injected female mice were mated with males of proven fertility, a subset of embryos died in utero, and most of those that survived exhibited increased body weight. Conclusion Taken together, our data reveal that activin betaA can directly influence the estrous cycle, an integral part of the reproduction in female mice and activin betaA can also influence the embryo development as an endocrine fashion.

  17. A crucial role of activin A-mediated growth hormone suppression in mouse and human heart failure.

    Directory of Open Access Journals (Sweden)

    Noritoshi Fukushima

    Full Text Available Infusion of bone marrow-derived mononuclear cells (BMMNC has been reported to ameliorate cardiac dysfunction after acute myocardial infarction. In this study, we investigated whether infusion of BMMNC is also effective for non-ischemic heart failure model mice and the underlying mechanisms. Intravenous infusion of BMMNC showed transient cardioprotective effects on animal models with dilated cardiomyopathy (DCM without their engraftment in heart, suggesting that BMMNC infusion improves cardiac function via humoral factors rather than their differentiation into cardiomyocytes. Using conditioned media from sorted BMMNC, we found that the cardioprotective effects were mediated by growth hormone (GH secreted from myeloid (Gr-1(+ cells and the effects was partially mediated by signal transducer and activator of transcription 3 in cardiomyocytes. On the other hand, the GH expression in Gr-1(+ cells was significantly downregulated in DCM mice compared with that in healthy control, suggesting that the environmental cue in heart failure might suppress the Gr-1(+ cells function. Activin A was upregulated in the serum of DCM models and induced downregulation of GH levels in Gr-1(+ cells and serum. Furthermore, humoral factors upregulated in heart failure including angiotensin II upregulated activin A in peripheral blood mononuclear cells (PBMNC via activation of NFκB. Similarly, serum activin A levels were also significantly higher in DCM patients with heart failure than in healthy subjects and the GH levels in conditioned medium from PBMNC of DCM patients were lower than that in healthy subjects. Inhibition of activin A increased serum GH levels and improved cardiac function of DCM model mice. These results suggest that activin A causes heart failure by suppressing GH activity and that inhibition of activin A might become a novel strategy for the treatment of heart failure.

  18. The Expression of Human Cytomegalovirus MicroRNA MiR-UL148D during Latent Infection in Primary Myeloid Cells Inhibits Activin A-triggered Secretion of IL-6.

    Science.gov (United States)

    Lau, Betty; Poole, Emma; Krishna, Benjamin; Sellart, Immaculada; Wills, Mark R; Murphy, Eain; Sinclair, John

    2016-08-05

    The successful establishment and maintenance of human cytomegalovirus (HCMV) latency is dependent on the expression of a subset of viral genes. Whilst the exact spectrum and functions of these genes are far from clear, inroads have been made for protein-coding genes. In contrast, little is known about the expression of non-coding RNAs. Here we show that HCMV encoded miRNAs are expressed de novo during latent infection of primary myeloid cells. Furthermore, we demonstrate that miR-UL148D, one of the most highly expressed viral miRNAs during latent infection, directly targets the cellular receptor ACVR1B of the activin signalling axis. Consistent with this, we observed upregulation of ACVR1B expression during latent infection with a miR-UL148D deletion virus (ΔmiR-UL148D). Importantly, we observed that monocytes latently infected with ΔmiR-UL148D are more responsive to activin A stimulation, as demonstrated by their increased secretion of IL-6. Collectively, our data indicates miR-UL148D inhibits ACVR1B expression in latently infected cells to limit proinflammatory cytokine secretion, perhaps as an immune evasion strategy or to postpone cytokine-induced reactivation until conditions are more favourable. This is the first demonstration of an HCMV miRNA function during latency in primary myeloid cells, implicating that small RNA species may contribute significantly to latent infection.

  19. RhoA regulates Activin B-induced stress fiber formation and migration of bone marrow-derived mesenchymal stromal cell through distinct signaling.

    Science.gov (United States)

    Wang, Xueer; Tang, Pei; Guo, Fukun; Zhang, Min; Chen, Yinghua; Yan, Yuan; Tian, Zhihui; Xu, Pengcheng; Zhang, Lei; Zhang, Lu; Zhang, Lin

    2017-01-01

    In our previous study, Activin B induced actin stress fiber formation and cell migration in Bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. However, the underlying molecular mechanisms are not well studied. RhoA is recognized to play a critical role in the regulation of actomyosin cytoskeletal organization and cell migration. Pull-down assay was performed to investigate the activity of RhoA. The dominant-negative mutants of RhoA (RhoA(N19)) was used to determine whether RhoA has a role in Activin B-induced cytoskeleton organization and cell migration in BMSCs. Cytoskeleton organization was examined by fluorescence Rhodamine-phalloidin staining, and cell migration by transwell and cell scratching assay. Western blot was carried out to investigate downstream signaling cascade of RhoA. Inhibitor and siRNAs were used to detect the role of downstream signaling in stress fiber formation and/or cell migration. RhoA was activated by Activin B in BMSCs. RhoA(N19) blocked Activin B-induced stress fiber formation and cell migration. ROCK inhibitor blocked Activin B-induced stress fiber formation but enhanced BMSCs migration. Activin B induced phosphorylation of LIMK2 and Cofilin, which was abolished by ROCK inhibition. Both of siRNA LIMK2 and siRNA Cofilin inhibited Activin B-induced stress fiber formation. RhoA regulates Activin B-induced stress fiber formation and migration of BMSCs. A RhoA-ROCK-LIMK2-Cofilin signaling node exists and regulates actin stress fiber formation. RhoA regulates Activin B-induced cell migration independent of ROCK. Better understanding of the molecular mechanisms of BMSCs migration will help optimize therapeutic strategy to target BMSCs at injured tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Activin Plays a Key Role in the Maintenance of Long-Term Memory and Late-LTP

    Science.gov (United States)

    Ageta, Hiroshi; Ikegami, Shiro; Miura, Masami; Masuda, Masao; Migishima, Rika; Hino, Toshiaki; Takashima, Noriko; Murayama, Akiko; Sugino, Hiromu; Setou, Mitsutoshi; Kida, Satoshi; Yokoyama, Minesuke; Hasegawa, Yoshihisa; Tsuchida, Kunihiro; Aosaki, Toshihiko; Inokuchi, Kaoru

    2010-01-01

    A recent study has revealed that fear memory may be vulnerable following retrieval, and is then reconsolidated in a protein synthesis-dependent manner. However, little is known about the molecular mechanisms of these processes. Activin [beta]A, a member of the TGF-[beta] superfamily, is increased in activated neuronal circuits and regulates…

  1. A late requirement for Wnt and FGF signaling during activin-induced formation of foregut endoderm from mouse embryonic stem cells

    DEFF Research Database (Denmark)

    Hansson, Mattias; Olesen, Dorthe R; Peterslund, Janny M L

    2009-01-01

    Here we examine how BMP, Wnt, and FGF signaling modulate activin-induced mesendodermal differentiation of mouse ES cells grown under defined conditions in adherent monoculture. We monitor ES cells containing reporter genes for markers of primitive streak (PS) and its progeny and extend previous....... Notably, activin induction of Gsc-GFP(+) cells appears refractory to inhibition of canonical Wnt signaling but shows a dependence on early as well as late FGF signaling. Additionally, we find a late dependence on FGF signaling during induction of Sox17(+) cells by activin while BMP4-induced T expression...... requires FGF signaling in adherent but not aggregate culture. Lastly, we demonstrate that activin-induced definitive endoderm derived from mouse ES cells can incorporate into the developing foregut endoderm in vivo and adopt a mostly anterior foregut character after further culture in vitro....

  2. Activin/Nodal Signaling Supports Retinal Progenitor Specification in a Narrow Time Window during Pluripotent Stem Cell Neuralization

    Directory of Open Access Journals (Sweden)

    Michele Bertacchi

    2015-10-01

    Full Text Available Retinal progenitors are initially found in the anterior neural plate region known as the eye field, whereas neighboring areas undertake telencephalic or hypothalamic development. Eye field cells become specified by switching on a network of eye field transcription factors, but the extracellular cues activating this network remain unclear. In this study, we used chemically defined media to induce in vitro differentiation of mouse embryonic stem cells (ESCs toward eye field fates. Inhibition of Wnt/β-catenin signaling was sufficient to drive ESCs to telencephalic, but not retinal, fates. Instead, retinal progenitors could be generated from competent differentiating mouse ESCs by activation of Activin/Nodal signaling within a narrow temporal window corresponding to the emergence of primitive anterior neural progenitors. Activin also promoted eye field gene expression in differentiating human ESCs. Our results reveal insights into the mechanisms of eye field specification and open new avenues toward the generation of retinal progenitors for translational medicine.

  3. IMMUNOLOCALIZATION OF INHIBIN/ACTIVIN SUBUNITS AND STEROIDOGENIC ENZYMES IN THE TESTES OF AN ADULT AFRICAN ELEPHANT (LOXODONTA AFRICANA).

    Science.gov (United States)

    Li, Qinglin; Lu, Lu; Weng, Qiang; Kawakami, Shigehisa; Saito, Eriko; Yamamoto, Tatsuya; Yamamoto, Yuki; Kaewmanee, Saroch; Nagaoka, Kentaro; Watanabe, Gen; Taya, Kazuyoshi

    2016-06-01

    In this case report, the authors investigated immunolocalization of inhibin α and inhibin/activin βA and βB subunits, as well as steroidogenic enzymes, in the testes of an African elephant. Testes were collected from a reproductively active male African elephant (24 yr old) at autopsy. Histologically, all types of spermatogenic cells including mature-phase spermatozoa were found in the seminiferous tubules. Positive immunostaining for inhibin α and inhibin/activin βA and βB subunits was observed in Sertoli and Leydig cells. In addition, P450scc, 3βHSD, P450c17, and P450arom were also detected in the cytoplasm of Leydig cells. These results suggested that Leydig cells of adult African elephant testes have the ability to synthesize progestin, androgen, and estrogen, whereas both Sertoli and Leydig cells appear as a major source of inhibin secretion in the male African elephant.

  4. Activin/Nodal Signaling Supports Retinal Progenitor Specification in a Narrow Time Window during Pluripotent Stem Cell Neuralization

    Science.gov (United States)

    Bertacchi, Michele; Lupo, Giuseppe; Pandolfini, Luca; Casarosa, Simona; D’Onofrio, Mara; Pedersen, Roger A.; Harris, William A.; Cremisi, Federico

    2015-01-01

    Summary Retinal progenitors are initially found in the anterior neural plate region known as the eye field, whereas neighboring areas undertake telencephalic or hypothalamic development. Eye field cells become specified by switching on a network of eye field transcription factors, but the extracellular cues activating this network remain unclear. In this study, we used chemically defined media to induce in vitro differentiation of mouse embryonic stem cells (ESCs) toward eye field fates. Inhibition of Wnt/β-catenin signaling was sufficient to drive ESCs to telencephalic, but not retinal, fates. Instead, retinal progenitors could be generated from competent differentiating mouse ESCs by activation of Activin/Nodal signaling within a narrow temporal window corresponding to the emergence of primitive anterior neural progenitors. Activin also promoted eye field gene expression in differentiating human ESCs. Our results reveal insights into the mechanisms of eye field specification and open new avenues toward the generation of retinal progenitors for translational medicine. PMID:26388287

  5. Distinct modes of SMAD2 chromatin binding and remodeling shape the transcriptional response to NODAL/Activin signaling

    Science.gov (United States)

    Coda, Davide M; Gaarenstroom, Tessa; East, Philip; Patel, Harshil; Miller, Daniel S J; Lobley, Anna; Matthews, Nik; Stewart, Aengus; Hill, Caroline S

    2017-01-01

    NODAL/Activin signaling orchestrates key processes during embryonic development via SMAD2. How SMAD2 activates programs of gene expression that are modulated over time however, is not known. Here we delineate the sequence of events that occur from SMAD2 binding to transcriptional activation, and the mechanisms underlying them. NODAL/Activin signaling induces dramatic chromatin landscape changes, and a dynamic transcriptional network regulated by SMAD2, acting via multiple mechanisms. Crucially we have discovered two modes of SMAD2 binding. SMAD2 can bind pre-acetylated nucleosome-depleted sites. However, it also binds to unacetylated, closed chromatin, independently of pioneer factors, where it induces nucleosome displacement and histone acetylation. For a subset of genes, this requires SMARCA4. We find that long term modulation of the transcriptional responses requires continued NODAL/Activin signaling. Thus SMAD2 binding does not linearly equate with transcriptional kinetics, and our data suggest that SMAD2 recruits multiple co-factors during sustained signaling to shape the downstream transcriptional program. DOI: http://dx.doi.org/10.7554/eLife.22474.001 PMID:28191871

  6. Activin A induces ovine follicle stimulating hormone beta using -169/-58 bp of its promoter and a simple TATA box

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    Miller William L

    2009-06-01

    Full Text Available Abstract Background Activin A increases production of follicle stimulating hormone (FSH by inducing transcription of its beta subunit (FSHB. This induction has been studied here in LbetaT2 gonadotropes using transient expression of ovine FSHBLuc (-4741 bp of ovine FSHB promoter plus exon/intron 1 linked to Luc. Several sequences between -169/-58 bp of the ovine FSHB proximal promoter are necessary for induction by activin A in LbetaT2 cells, but deletions between -4741/-752 bp decrease induction > 70% suggesting the existence of other important 5' sequences. Induction disappears if a minimal T81 thymidine kinase promoter replaces the ovine FSHB TATA box and 3' exon/intron. The study reported here was designed to determine if sequences outside -169/-58 bp are important for induction of ovine FSHB by activin A. Methods Progressively longer deletions of ovine FSHBLuc were created between -4741/-195 bp. Deletions internal to this region were created also, but replaced with substitute DNA. The ovine FSHB TATA box region (-40/+3 bp was replaced by thymidine kinase and rat prolactin minimal promoters, and substitutions were made in 3' intron/exon sequences. All constructs were tested for basal and activin A-induced expression in LbetaT2 cells. Results Successive 5' deletions progressively lowered fold-induction by activin A from 9.5 to zero, but progressively increased basal expression. Replacing deletions with substitute DNA showed no changes in basal expression or fold-induction. Induction by activin A was supported by the minimal rat prolactin promoter (TATA box but not the thymidine kinase promoter (no TATA box. Replacement mutations in the 3' region did not decrease induction by activin A. Conclusion The data show that specific ovine FSHB sequences 5' to -175 bp or 3' of the transcription start site are not required for induction by activin A. A minimal TATA box promoter supports induction by activin A, but the sequence between the TATA box and

  7. The Notch ligand Delta-like 1 integrates inputs from TGFbeta/Activin and Wnt pathways

    Energy Technology Data Exchange (ETDEWEB)

    Bordonaro, Michael, E-mail: mbordonaro@tcmedc.org; Tewari, Shruti, E-mail: stewari@tcmedc.org; Atamna, Wafa, E-mail: watamna@tcmedc.org; Lazarova, Darina L., E-mail: dlazarova@tcmedc.org

    2011-06-10

    Unlike the well-characterized nuclear function of the Notch intracellular domain, it has been difficult to identify a nuclear role for the ligands of Notch. Here we provide evidence for the nuclear function of the Notch ligand Delta-like 1 in colon cancer (CC) cells exposed to butyrate. We demonstrate that the intracellular domain of Delta-like 1 (Dll1icd) augments the activity of Wnt signaling-dependent reporters and that of the promoter of the connective tissue growth factor (CTGF) gene. Data suggest that Dll1icd upregulates CTGF promoter activity through both direct and indirect mechanisms. The direct mechanism is supported by co-immunoprecipitation of endogenous Smad2/3 proteins and Dll1 and by chromatin immunoprecipitation analyses that revealed the occupancy of Dll1icd on CTGF promoter sequences containing a Smad binding element. The indirect upregulation of CTGF expression by Dll1 is likely due to the ability of Dll1icd to increase Wnt signaling, a pathway that targets CTGF. CTGF expression is induced in butyrate-treated CC cells and results from clonal growth assays support a role for CTGF in the cell growth-suppressive role of butyrate. In conclusion, integration of the Notch, Wnt, and TGFbeta/Activin signaling pathways is in part mediated by the interactions of Dll1 with Smad2/3 and Tcf4.

  8. Effect of physical training on liver expression of activin A and follistatin in a nonalcoholic fatty liver disease model in rats

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.N. [Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Bueno, P.G. [Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Avó, L.R.S. [Departamento de Medicina, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Nonaka, K.O.; Selistre-Araújo, H.S. [Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Leal, A.M.O. [Departamento de Medicina, Universidade Federal de São Carlos, São Carlos, SP (Brazil)

    2014-07-25

    Nonalcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver and is associated with obesity and insulin resistance. Activin A is a member of the transforming growth factor beta (TGF)-β superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin. Exercise is an important therapeutic strategy to reduce the metabolic effects of obesity. We evaluated the pattern of activin A and follistatin liver expression in obese rats subjected to swimming exercise. Control rats (C) and high-fat (HF) diet-fed rats were randomly assigned to a swimming training group (C-Swim and HF-Swim) or a sedentary group (C-Sed and HF-Sed). Activin βA subunit mRNA expression was significantly higher in HF-Swim than in HF-Sed rats. Follistatin mRNA expression was significantly lower in C-Swim and HF-Swim than in either C-Sed or HF-Sed animals. There was no evidence of steatosis or inflammation in C rats. In contrast, in HF animals the severity of steatosis ranged from grade 1 to grade 3. The extent of liver parenchyma damage was less in HF-Swim animals, with the severity of steatosis ranging from grade 0 to grade 1. These data showed that exercise may reduce the deleterious effects of a high-fat diet on the liver, suggesting that the local expression of activin-follistatin may be involved.

  9. Effect of physical training on liver expression of activin A and follistatin in a nonalcoholic fatty liver disease model in rats.

    Science.gov (United States)

    Silva, R N; Bueno, P G; Avó, L R S; Nonaka, K O; Selistre-Araújo, H S; Leal, A M O

    2014-09-01

    Nonalcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver and is associated with obesity and insulin resistance. Activin A is a member of the transforming growth factor beta (TGF)-β superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin. Exercise is an important therapeutic strategy to reduce the metabolic effects of obesity. We evaluated the pattern of activin A and follistatin liver expression in obese rats subjected to swimming exercise. Control rats (C) and high-fat (HF) diet-fed rats were randomly assigned to a swimming training group (C-Swim and HF-Swim) or a sedentary group (C-Sed and HF-Sed). Activin βA subunit mRNA expression was significantly higher in HF-Swim than in HF-Sed rats. Follistatin mRNA expression was significantly lower in C-Swim and HF-Swim than in either C-Sed or HF-Sed animals. There was no evidence of steatosis or inflammation in C rats. In contrast, in HF animals the severity of steatosis ranged from grade 1 to grade 3. The extent of liver parenchyma damage was less in HF-Swim animals, with the severity of steatosis ranging from grade 0 to grade 1. These data showed that exercise may reduce the deleterious effects of a high-fat diet on the liver, suggesting that the local expression of activin-follistatin may be involved.

  10. Effect of physical training on liver expression of activin A and follistatin in a nonalcoholic fatty liver disease model in rats

    Directory of Open Access Journals (Sweden)

    R.N. Silva

    2014-09-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is characterized by fat accumulation in the liver and is associated with obesity and insulin resistance. Activin A is a member of the transforming growth factor beta (TGF-β superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin. Exercise is an important therapeutic strategy to reduce the metabolic effects of obesity. We evaluated the pattern of activin A and follistatin liver expression in obese rats subjected to swimming exercise. Control rats (C and high-fat (HF diet-fed rats were randomly assigned to a swimming training group (C-Swim and HF-Swim or a sedentary group (C-Sed and HF-Sed. Activin βA subunit mRNA expression was significantly higher in HF-Swim than in HF-Sed rats. Follistatin mRNA expression was significantly lower in C-Swim and HF-Swim than in either C-Sed or HF-Sed animals. There was no evidence of steatosis or inflammation in C rats. In contrast, in HF animals the severity of steatosis ranged from grade 1 to grade 3. The extent of liver parenchyma damage was less in HF-Swim animals, with the severity of steatosis ranging from grade 0 to grade 1. These data showed that exercise may reduce the deleterious effects of a high-fat diet on the liver, suggesting that the local expression of activin-follistatin may be involved.

  11. Activin Enhances α- to β-Cell Transdifferentiation as a Source For β-Cells In Male FSTL3 Knockout Mice.

    Science.gov (United States)

    Brown, Melissa L; Andrzejewski, Danielle; Burnside, Amy; Schneyer, Alan L

    2016-03-01

    Diabetes results from inadequate β-cell number and/or function to control serum glucose concentrations so that replacement of lost β-cells could become a viable therapy for diabetes. In addition to embryonic stem cell sources for new β-cells, evidence for transdifferentiation/reprogramming of non-β-cells to functional β-cells is accumulating. In addition, de-differentiation of β-cells observed in diabetes and their subsequent conversion to α-cells raises the possibility that adult islet cell fate is malleable and controlled by local hormonal and/or environmental cues. We previously demonstrated that inactivation of the activin antagonist, follistatin-like 3 (FSTL3) resulted in β-cell expansion and improved glucose homeostasis in the absence of β-cell proliferation. We recently reported that activin directly suppressed expression of critical α-cell genes while increasing expression of β-cell genes, supporting the hypothesis that activin is one of the local hormones controlling islet cell fate and that increased activin signaling accelerates α- to β-cell transdifferentiation. We tested this hypothesis using Gluc-Cre/yellow fluorescent protein (YFP) α-cell lineage tracing technology combined with FSTL3 knockout (KO) mice to label α-cells with YFP. Flow cytometry was used to quantify unlabeled and labeled α- and β-cells. We found that Ins+/YFP+ cells were significantly increased in FSTL3 KO mice compared with wild type littermates. Labeled Ins+/YFP+ cells increased significantly with age in FSTL3 KO mice but not wild type littermates. Sorting results were substantiated by counting fluorescently labeled cells in pancreatic sections. Activin treatment of isolated islets significantly increased the number of YFP+/Ins+ cells. These results suggest that α- to β-cell transdifferentiation is influenced by activin signaling and may contribute substantially to β-cell mass.

  12. The glycoprotein-hormones activin A and inhibin A interfere with dendritic cell maturation

    Directory of Open Access Journals (Sweden)

    Reichardt Holger M

    2008-05-01

    Full Text Available Abstract Background Pregnancy represents an exclusive situation in which the immune and the endocrine system cooperate to prevent rejection of the embryo by the maternal immune system. While immature dendritic cells (iDC in the early pregnancy decidua presumably contribute to the establishment of peripheral tolerance, glycoprotein-hormones of the transforming growth factor beta (TGF-beta family including activin A (ActA and inhibin A (InA are candidates that could direct the differentiation of DCs into a tolerance-inducing phenotype. Methods To test this hypothesis we generated iDCs from peripheral-blood-monocytes and exposed them to TGF-beta1, ActA, as well as InA and Dexamethasone (Dex as controls. Results Both glycoprotein-hormones prevented up-regulation of HLA-DR during cytokine-induced DC maturation similar to Dex but did not influence the expression of CD 40, CD 83 and CD 86. Visualization of the F-actin cytoskeleton confirmed that the DCs retained a partially immature phenotype under these conditions. The T-cell stimulatory capacity of DCs was reduced after ActA and InA exposure while the secretion of cytokines and chemokines was unaffected. Conclusion These findings suggest that ActA and InA interfere with selected aspects of DC maturation and may thereby help preventing activation of allogenic T-cells by the embryo. Thus, we have identified two novel members of the TGF-beta superfamily that could promote the generation of tolerance-inducing DCs.

  13. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  14. Transforming Growth Factor β/Activin Signaling Functions as a Sugar-Sensing Feedback Loop to Regulate Digestive Enzyme Expression

    Directory of Open Access Journals (Sweden)

    Wen-bin Alfred Chng

    2014-10-01

    Full Text Available Organisms need to assess their nutritional state and adapt their digestive capacity to the demands for various nutrients. Modulation of digestive enzyme production represents a rational step to regulate nutriment uptake. However, the role of digestion in nutrient homeostasis has been largely neglected. In this study, we analyzed the mechanism underlying glucose repression of digestive enzymes in the adult Drosophila midgut. We demonstrate that glucose represses the expression of many carbohydrases and lipases. Our data reveal that the consumption of nutritious sugars stimulates the secretion of the transforming growth factor β (TGF-β ligand, Dawdle, from the fat body. Dawdle then acts via circulation to activate TGF-β/Activin signaling in the midgut, culminating in the repression of digestive enzymes that are highly expressed during starvation. Thus, our study not only identifies a mechanism that couples sugar sensing with digestive enzyme expression but points to an important role of TGF-β/Activin signaling in sugar metabolism.

  15. DNA Damage Drives an Activin A-Dependent Induction of COX-2 in Premalignant Cells and Lesions

    Science.gov (United States)

    Fordyce, Colleen; Fessenden, Tim; Pickering, Curtis; Jung, Jason; Singla, Veena; Berman, Hal; Tlsty, Thea

    2010-01-01

    COX-2 catalyzes the rate-limiting step in the synthesis of prostaglandins. Its overexpression induces numerous tumor-promoting phenotypes and is associated with cancer metastasis and poor clinical outcome. Although COX-2 inhibitors are promising chemotherapeutic and chemopreventative agents for cancer, the risk of significant cardiovascular and gastrointestinal complications currently outweighs their potential benefits. Systemic complications of COX-2 inhibition could be avoided by specifically decreasing COX-2 expression in epithelial cells. To that end, we have investigated the signal transduction pathway regulating COX-2 expression in response to DNA damage in breast epithelial cells. In variant human mammary epithelial cells that have silenced p16 (vHMEC), double strand DNA damage or telomere malfunction results in a p53-and activin A-dependent induction of COX-2 and continued proliferation. In contrast, telomere malfunction in HMEC with an intact p16/Rb pathway induces cell cycle arrest. Importantly, in ductal carcinoma in situ (DCIS) lesions, high COX-2 expression is associated with high γH2AX, TRF2, activin A and telomere malfunction. These data demonstrate that DNA damage and telomere malfunction can have both cell autonomous and cell non-autonomous consequences and provides a novel mechanism for the propagation of tumorigenesis. PMID:20028875

  16. DNA damage drives an activin a-dependent induction of cyclooxygenase-2 in premalignant cells and lesions.

    Science.gov (United States)

    Fordyce, Colleen; Fessenden, Tim; Pickering, Curtis; Jung, Jason; Singla, Veena; Berman, Hal; Tlsty, Thea

    2010-02-01

    Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the synthesis of prostaglandins. Its overexpression induces numerous tumor-promoting phenotypes and is associated with cancer metastasis and poor clinical outcome. Although COX-2 inhibitors are promising chemotherapeutic and chemopreventative agents for cancer, the risk of significant cardiovascular and gastrointestinal complications currently outweighs their potential benefits. Systemic complications of COX-2 inhibition could be avoided by specifically decreasing COX-2 expression in epithelial cells. To that end, we have investigated the signal transduction pathway regulating the COX-2 expression in response to DNA damage in breast epithelial cells. In variant human mammary epithelial cells that have silenced p16 (vHMEC), double-strand DNA damage or telomere malfunction results in a p53- and activin A-dependent induction of COX-2 and continued proliferation. In contrast, telomere malfunction in HMEC with an intact p16/Rb pathway induces cell cycle arrest. Importantly, in ductal carcinoma in situ lesions, high COX-2 expression is associated with high gammaH2AX, TRF2, activin A, and telomere malfunction. These data show that DNA damage and telomere malfunction can have both cell-autonomous and cell-nonautonomous consequences and can provide a novel mechanism for the propagation of tumorigenesis.

  17. FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Lina, E-mail: linasui@vub.ac.be [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Mfopou, Josue K. [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Geens, Mieke; Sermon, Karen [Department of Embryology and Genetics, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Bouwens, Luc [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium)

    2012-09-28

    Highlights: Black-Right-Pointing-Pointer Deep study the FGF signaling role during DE specification in the context of hESCs. Black-Right-Pointing-Pointer DE differentiation from hESCs has an early dependence on FGF signaling. Black-Right-Pointing-Pointer A serum-free DE protocol is developed based on the findings. Black-Right-Pointing-Pointer The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study, we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.

  18. Enhanced differentiation of human embryonic stem cells to mesenchymal progenitors by inhibition of TGF-beta/Activin/Nodal signaling using SB-431542

    DEFF Research Database (Denmark)

    Mahmood, Amer; Harkness, Linda; Schrøder, Henrik Daa

    2010-01-01

    progenitor cells. We demonstrate that inhibition of TGF-beta/Activin/Nodal signaling during embryoid bodies (EB) formation using SB-431542 (SB) in serum free medium, markedly up-regulated paraxial mesodermal markers (TBX6, TBX5), and several myogenic developmental markers including early myogenic...

  19. TAK-1/p38/nNFκB signaling inhibits myoblast differentiation by increasing levels of Activin A

    Directory of Open Access Journals (Sweden)

    Trendelenburg Anne

    2012-02-01

    Full Text Available Abstract Background Skeletal-muscle differentiation is required for the regeneration of myofibers after injury. The differentiation capacity of satellite cells is impaired in settings of old age, which is at least one factor in the onset of sarcopenia, the age-related loss of skeletal-muscle mass and major cause of frailty. One important cause of impaired regeneration is increased levels of transforming growth factor (TGF-β accompanied by reduced Notch signaling. Pro-inflammatory cytokines are also upregulated in aging, which led us hypothesize that they might potentially contribute to impaired regeneration in sarcopenia. Thus, in this study, we further analyzed the muscle differentiation-inhibition pathway mediated by pro-inflammatory cytokines in human skeletal muscle cells (HuSKMCs. Methods We studied the modulation of HuSKMC differentiation by the pro-inflammatory cytokines interleukin (IL-1α and tumor necrosis factor (TNF-α The grade of differentiation was determined by either imaging (fusion index or creatine kinase (CK activity, a marker of muscle differentiation. Secretion of TGF-β proteins during differentiation was assessed by using a TGF-β-responsive reporter-gene assay and further identified by means of pharmacological and genetic inhibitors. In addition, signaling events were monitored by western blotting and reverse transcription PCR, both in HuSKMC cultures and in samples from a rat sarcopenia study. Results The pro-inflammatory cytokines IL-1α and TNF-α block differentiation of human myoblasts into myotubes. This anti-differentiation effect requires activation of TGF-β-activated kinase (TAK-1. Using pharmacological and genetic inhibitors, the TAK-1 pathway could be traced to p38 and NFκB. Surprisingly, the anti-differentiation effect of the cytokines required the transcriptional upregulation of Activin A, which in turn acted through its established signaling pathway: ActRII/ALK/SMAD. Inhibition of Activin A signaling was

  20. Mutations in endoglin and in activin receptor-like kinase 1 among Danish patients with hereditary haemorrhagic telangiectasia

    DEFF Research Database (Denmark)

    Brusgaard, K; Kjeldsen, A D; Poulsen, L

    2004-01-01

    , a presumed spontaneous mutation was characterized. The method developed proved to be very sensitive for mutation detection in both ENG and ALK1. Genetic screening in HHT families facilitates an early treatment strategy for silent HHT manifestations in first degree relatives....... protocol for mutation scanning of the two loci. Twenty-five Danish HHT families were tested. A total of eight new as well as seven previously reported mutations were identified. A founder mutation was characterized present in seven families and possibly introduced around 350 years ago. In one individual...

  1. Stimulation of circus movement by activin, bFGF and TGF-beta 2 in isolated animal cap cells of Xenopus laevis.

    Science.gov (United States)

    Minoura, I; Nakamura, H; Tashiro, K; Shiokawa, K

    1995-01-01

    Lobopodium is a hyaline cytoplasmic protrusion which rotates circumferencially around a cell. This movement is called circus movement, which is seen in dissociated cells of amphibian embryos. Relative abundance of the lobopodia-forming cells changes temporally and spatially within Xenopus embryos, reflecting stage-dependent difference of morphogenetic movements. The lobopodia-forming activity of dissociated animal cap cells was stimulated strongly by activin and bFGF, and weakly by TGF-beta 2. In addition, activin A was found to stimulate cellular attachment to the substratum when the cultivation lasted long. Thus, mesoderm-inducing growth factors stimulate lobopodia formation and cellular movements which may be necessary for gastrulation and neurulation in Xenopus early embryos.

  2. Up-regulation of JAM-1 in AR42J cells treated with activin A and betacellulin and the diabetic regenerating islets.

    Science.gov (United States)

    Yoshikumi, Yukako; Ohno, Hideki; Suzuki, Junko; Isshiki, Masashi; Morishita, Yasuyuki; Ohnishi, Hirohide; Yasuda, Hiroshi; Omata, Masao; Fujita, Toshiro; Mashima, Hirosato

    2008-08-01

    Pancreatic AR42J cells demonstrate the pluripotency in precursor cells of the gut endoderm and also provide an excellent model system to study the differentiation of the pancreas. Using the mRNA differential display technique, we identified junctional adhesion molecule-1 (JAM-1), a component of the tight junction, was highly up-regulated during the differentiation of AR42J cells, although junctions were not formed. The expression level of JAM-1 showed an up-regulation in the mRNA level after 3 hours and in the protein level after 24 hours in [activin A + betacellulin]-treated AR42J cells. The expressions of its signaling molecules, PAR-3 and atypical PKC lambda, also increased after the addition of activin A + betacellulin. When JAM-1 was over-expressed in [activin A + betacellulin]-treated AR42J cells, tagged-JAM-1 was observed in cytoplasm as vesicular structures and JAM-1 was colocalized with Rab3B and Rab13, members of the Rab family expressed at tight junctions. In streptozotocin-induced regenerating islets, the expression of JAM-1 was also up-regulated in the mRNA level and the protein level. JAM-1 might therefore play an important role in the differentiation of AR42J cells and the regeneration of pancreatic islets.

  3. 牙鲆(Paralichthys olivaceus) Activin 基因两种β亚基的启动子克隆及生物信息学分析%Bioinformatic Characterization of Promoters of Two Activin-βSubunit Genes in Paralichthys olivaceus

    Institute of Scientific and Technical Information of China (English)

    刘蒙蒙; 王晶; 高金宁; 马丽曼; 张全启

    2015-01-01

    Activin is a member of the transforming growth factor-β (TGF-β) family and regulates sex hormones. It was originally discovered in pig ovarian follicular fluid. Activin contains two β subunits and plays a vital role in the hypothalamus-pituitary-gonad axis (HPG). It regulates the secretion of pituitary gonadotropin, the production of steroid hormones and the maturation of oocyte in ovary. Paralichthys olivaceus is a type of important commercial fish species that has advantageous traits in aquaculture such as the fast growth rate. Better understanding of its reproduction mechanism is essential for the guidance of the breeding of P. olivaceus. In this study, we analyzed the expression and regulation of Activin gene related to the reproductive endocrinology of P. olivaceus. Our data should provide important information for future studies on biological functions of Activin and for the practice in the culture of P. olivaceus. We used the genome walking method to obtain the partial sequence of promoters located in the upstream of Activin βA and βB genes of P. olivaceus, and predicted the binding sites of transcriptional regulation elements using the bioinformatical method. The promoters of these two genes were 2.7 kb and 2.4 kb in length respectively. The results showed that the TATA box of Activin βB was located at 31 bp in the upstream region of the transcription initiation site, however this structure was not found in Activin βA. We found in the two promoters a number of binding sites of the transcription factors including Sp1, Oct-1, C/EBP, CREB, GATA-1, c-Jun, HNF-3, HNF-1, and USF. Moreover, we also found multiple transcription binding sites of endocrine-related factors such as Pit-1, ER, PR, GR, RAR, and RXR. However, the binding sites of MyoD, myogenin and SRY were only found in Activin βA. In conclusion, the bioinformatical analysis suggested that the basic and hormone-inducing expression of both Activin βA and βB was regulated by a variety of factors

  4. Maternal circulating levels of activin A, inhibin A, sFlt-1 and endoglin at parturition in normal pregnancy and pre-eclampsia.

    Directory of Open Access Journals (Sweden)

    Aparna Reddy

    Full Text Available BACKGROUND: Maternal circulating levels of anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFlt-1, endoglin (sEng and placental proteins like activin A and inhibin A are increased before the onset of pre-eclampsia. There is evidence for oxidative stress in pre eclampsia. Recently it was shown that placental oxygen concentration is related to sFlt-1 and inhibin A. In addition it is reported that oxidative stress markers are increased in placental tissue delivered after labour. Therefore, the objective of this study is to investigate if these proteins are altered in maternal circulation of labouring pre-eclampsia and normal pregnancies. METHODOLOGY: To assess the effects of labour, samples were taken from 10 normal pregnant (NP and 10 pre-eclamptic (PE women pre-labour, full dilation, placental delivery and 24 h. To assess the effects of placental delivery, plasma samples were taken from 10NP and 10PE women undergoing elective Caesarean section, pre-delivery, placental delivery and 10 min, 60 min and 24 h post delivery. SFlt-1 and sEng and activin A and inhibin A were measured using commercial and in house ELISA's respectively. RESULTS: The levels of sFlt-1 and sEng were significantly higher in PE compared to NP women in both groups. In labour, sFlt-1 levels increased significantly at full dilatation in PE women, before declining by 24 hr. However there was no significant rise in sEng levels in labour. Activin A and inhibin A levels declined rapidly with placental delivery in NP and PE pregnancies. There was a significant rise in activin A levels during labour in PE compared to pre labour, but inhibin levels did not increase. CONCLUSION: Labour in pre-eclamptic women increases the levels of sFlt-1 and activin A. This pilot data suggests that increase in the maternal levels of these factors in labour could predict and/or contribute to the maternal syndrome postpartum.

  5. Tbx3 fosters pancreatic cancer growth by increased angiogenesis and activin/nodal-dependent induction of stemness

    Directory of Open Access Journals (Sweden)

    Lukas Perkhofer

    2016-09-01

    Full Text Available Cell fate decisions and pluripotency, but also malignancy depend on networks of key transcriptional regulators. The T-box transcription factor TBX3 has been implicated in the regulation of embryonic stem cell self-renewal and cardiogenesis. We have recently discovered that forced TBX3 expression in embryonic stem cells promotes mesendoderm specification directly by activating key lineage specification factors and indirectly by enhancing paracrine NODAL signalling. Interestingly, aberrant TBX3 expression is associated with breast cancer and melanoma formation. In other cancers, loss of TBX3 expression is associated with a more aggressive phenotype e.g. in gastric and cervical cancer. The precise function of TBX3 in pancreatic ductal adenocarcinoma remains to be determined. In the current study we provide conclusive evidence for TBX3 overexpression in pancreatic cancer samples as compared to healthy tissue. While proliferation remains unaltered, forced TBX3 expression strongly increases migration and invasion, but also angiogenesis in vitro and in vivo. Finally, we describe the TBX3-dependency of cancer stem cells that perpetuate themselves through an autocrine TBX3–ACTIVIN/NODAL signalling loop to sustain stemness. Thus, TBX3 is a new key player among pluripotency-related genes driving cancer formation.

  6. Effects of gonadotrophins, growth hormone, and activin A on enzymatically isolated follicle growth, oocyte chromatin organization, and steroid secretion.

    Science.gov (United States)

    Ola, Safiriyu Idowu; Ai, Jun-Shu; Liu, Jing-He; Wang, Qiang; Wang, Zhen-Bo; Chen, Da-Yuan; Sun, Qing-Yuan

    2008-01-01

    So far, standard follicle culture systems can produce blastocyst from less than 40% of the in vitro matured oocytes compared to over 70% in the in vivo counterpart. Because the capacity for embryonic development is strictly associated with the terminal stage of oocyte growth, the nuclear maturity status of the in vitro grown oocyte was the subject of this study. Mouse early preantral follicles (100-130 microm) and early antral follicles (170-200 microm) isolated enzymatically were cultured for 12 and 4 days, respectively, in a collagen-free dish. The serum-based media were supplemented with either 100 mIU/ml FSH (FSH only); 100 mIU/ml FSH + 10 mIU/ml LH (FSH-LH); 100 mIU/ml FSH + 1 mIU/ml GH (FSH-GH) or 100 mIU/ml FSH + 100 ng/ml activin A (FSH-AA). Follicle survival was highest in follicle stimulating hormone (FSH)-AA group in both cultured preantral (91.8%) and antral follicles (82.7%). Survival rates in the other groups ranged between 48% (FSH only, preantral follicle culture) and 78.7% (FSH only, antral follicle culture). Estradiol and progesterone were undetectable in medium lacking gonadotrophins while AA supplementation in synergy with FSH caused increased estradiol secretion and a simultaneously lowered progesterone secretion. Chromatin configuration of oocytes from surviving follicles at the end of culture revealed that there were twice more developmentally incompetent non-surrounded nucleolus (NSN) oocytes (>65%) than the competent surrounded nucleolus (SN) oocytes (produce optimum proportion of developmentally competent oocytes.

  7. Exogenous FGF10 can rescue an eye-open at birth phenotype of Fgf10-null mice by activating activin and TGFalpha-EGFR signaling.

    Science.gov (United States)

    Tao, Hirotaka; Ono, Katsuhiko; Kurose, Hitomi; Noji, Sumihare; Ohuchi, Hideyo

    2006-06-01

    Mutant mice deficient in the fibroblast growth factor 10 (Fgf10) gene exhibit an eye-open phenotype at birth. It has previously been shown that FGF10 has a dual role in proliferation and migration during the early and later stages of eyelid development, respectively. To verify the role of FGF10 during eyelid closure, explant culture of Fgf10-null eyelid anlagen was performed, by which it was examined whether or not exogenous FGF10 could rescue the expression of activin betaB and transforming growth factor alpha, known to be required for eyelid closure. We found that the expression of these genes was markedly induced while that of Shh or Ptch1, Ptch2 was not. We also observed the distribution of filamentous actin (F-actin) after FGF10 application in the mutant eyelid explant, finding that the FGF10 protein induced F-actin accumulation. We further examined filopodia of the eyelid leading edge cells, finding the length of the filopodia was significantly reduced in the mutant. These results verify that FGF10 promotes eyelid closure through activating activin and TGFalpha-EGFR signaling.

  8. Hanging drop cultures of human testis and testis cancer samples: a model used to investigate activin treatment effects in a preserved niche

    Science.gov (United States)

    Jørgensen, A; Young, J; Nielsen, J E; Joensen, U N; Toft, B G; Rajpert-De Meyts, E; Loveland, K L

    2014-01-01

    Background: Testicular germ cell tumours of young adults, seminoma or non-seminomas, are preceded by a pre-invasive precursor, carcinoma in situ (CIS), understood to arise through differentiation arrest of embryonic germ cells. Knowledge about the malignant transformation of germ cells is currently limited by the lack of experimental models. The aim of this study was to establish an experimental tissue culture model to maintain normal and malignant germ cells within their niche and allow investigation of treatment effects. Methods: Human testis and testis cancer specimens from orchidectomies were cultured in ‘hanging drops' and effects of activin A and follistatin treatment were investigated in seminoma cultures. Results: Testis fragments with normal spermatogenesis or CIS cells were cultured for 14 days with sustained proliferation of germ cells and CIS cells and without increased apoptosis. Seminoma cultures survived 7 days, with proliferating cells detectable during the first 5 days. Activin A treatment significantly reduced KIT transcript and protein levels in seminoma cultures, thereby demonstrating a specific treatment response. Conclusions: Hanging drop cultures of human testis and testis cancer samples can be employed to delineate mechanisms governing growth of normal, CIS and tumorigenic germ cells retained within their niche. PMID:24781282

  9. Angiomodulin is required for cardiogenesis of embryonic stem cells and is maintained by a feedback loop network of p63 and Activin-A.

    Science.gov (United States)

    Wolchinsky, Zohar; Shivtiel, Shoham; Kouwenhoven, Evelyn Nathalie; Putin, Daria; Sprecher, Eli; Zhou, Huiqing; Rouleau, Matthieu; Aberdam, Daniel

    2014-01-01

    The transcription factor p63, member of the p53 gene family, encodes for two main isoforms, TAp63 and ΔNp63 with distinct functions on epithelial homeostasis and cancer. Recently, we discovered that TAp63 is essential for in vitro cardiogenesis and heart development in vivo. TAp63 is expressed by embryonic endoderm and acts on cardiac progenitors by a cell-non-autonomous manner. In the present study, we search for cardiogenic secreted factors that could be regulated by TAp63 and, by ChIP-seq analysis, identified Angiomodulin (AGM), also named IGFBP7 or IGFBP-rP1. We demonstrate that AGM is necessary for cardiac commitment of embryonic stem cells (ESCs) and its regulation depends on TAp63 isoform. TAp63 directly activates both AGM and Activin-A during ESC cardiogenesis while these secreted factors modulate TAp63 gene expression by a feedback loop mechanism. The molecular circuitry controlled by TAp63 on AGM/Activin-A signaling pathway and thus on cardiogenesis emphasizes the importance of p63 during early cardiac development.

  10. Angiomodulin is required for cardiogenesis of embryonic stem cells and is maintained by a feedback loop network of p63 and Activin-A

    Directory of Open Access Journals (Sweden)

    Zohar Wolchinsky

    2014-01-01

    Full Text Available The transcription factor p63, member of the p53 gene family, encodes for two main isoforms, TAp63 and ΔNp63 with distinct functions on epithelial homeostasis and cancer. Recently, we discovered that TAp63 is essential for in vitro cardiogenesis and heart development in vivo. TAp63 is expressed by embryonic endoderm and acts on cardiac progenitors by a cell-non-autonomous manner. In the present study, we search for cardiogenic secreted factors that could be regulated by TAp63 and, by ChIP-seq analysis, identified Angiomodulin (AGM, also named IGFBP7 or IGFBP-rP1. We demonstrate that AGM is necessary for cardiac commitment of embryonic stem cells (ESCs and its regulation depends on TAp63 isoform. TAp63 directly activates both AGM and Activin-A during ESC cardiogenesis while these secreted factors modulate TAp63 gene expression by a feedback loop mechanism. The molecular circuitry controlled by TAp63 on AGM/Activin-A signaling pathway and thus on cardiogenesis emphasizes the importance of p63 during early cardiac development.

  11. Aldosterone breakthrough caused by chronic blockage of angiotensin II type 1 receptors in human adrenocortical cells: possible involvement of bone morphogenetic protein-6 actions.

    Science.gov (United States)

    Otani, Hiroyuki; Otsuka, Fumio; Inagaki, Kenichi; Suzuki, Jiro; Miyoshi, Tomoko; Kano, Yoshihiro; Goto, Junko; Ogura, Toshio; Makino, Hirofumi

    2008-06-01

    Circulating aldosterone concentrations occasionally increase after initial suppression with angiotensin II (Ang II) converting enzyme inhibitors or Ang II type 1 receptor blockers (ARBs), a phenomenon referred to as aldosterone breakthrough. However, the underlying mechanism causing the aldosterone breakthrough remains unknown. Here we investigated whether aldosterone breakthrough occurs in human adrenocortical H295R cells in vitro. We recently reported that bone morphogenetic protein (BMP)-6, which is expressed in adrenocortical cells, enhances Ang II- but not potassium-induced aldosterone production in human adrenocortical cells. Accordingly, we examined the roles of BMP-6 in aldosterone breakthrough induced by long-term treatment with ARB. Ang II stimulated aldosterone production by adrenocortical cells. This Ang II stimulation was blocked by an ARB, candesartan. Interestingly, the candesartan effects on Ang II-induced aldosterone synthesis and CYP11B2 expression were attenuated in a course of candesartan treatment for 15 d. The impairment of candesartan effects on Ang II-induced aldosterone production was also observed in Ang II- or candesartan-pretreated cells. Levels of Ang II type 1 receptor mRNA were not changed by chronic candesartan treatment. However, BMP-6 enhancement of Ang II-induced ERK1/2 signaling was resistant to candesartan. The BMP-6-induced Smad1, -5, and -8 phosphorylation, and BRE-Luc activity was augmented in the presence of Ang II and candesartan in the chronic phase. Chronic Ang II exposure decreased cellular expression levels of BMP-6 and its receptors activin receptor-like kinase-2 and activin type II receptor mRNAs. Cotreatment with candesartan reversed the inhibitory effects of Ang II on the expression levels of these mRNAs. The breakthrough phenomenon was attenuated by neutralization of endogenous BMP-6 and activin receptor-like kinase-2. Collectively, these data suggest that changes in BMP-6 availability and response may be involved

  12. The daf-4 gene encodes a bone morphogenetic protein receptor controlling C. elegans dauer larva development.

    Science.gov (United States)

    Estevez, M; Attisano, L; Wrana, J L; Albert, P S; Massagué, J; Riddle, D L

    1993-10-14

    The bone morphogenetic protein (BMP) family is a conserved group of signalling molecules within the transforming growth factor-beta (TGF-beta) superfamily. This group, including the Drosophila decapentaplegic (dpp) protein and the mammalian BMPs, mediates cellular interactions and tissue differentiation during development. Here we show that a homologue of human BMPs controls a developmental switch in the life cycle of the free-living soil nematode Caenorhabditis elegans. Starvation and overcrowding induce C. elegans to form a developmentally arrested, third-stage dauer larva. The daf-4 gene, which acts to inhibit dauer larva formation and promote growth, encodes a receptor protein kinase similar to the daf-1, activin and TGF-beta receptor serine/threonine kinases. When expressed in monkey COS cells, the daf-4 receptor binds human BMP-2 and BMP-4. The daf-4 receptor is the first to be identified for any growth factor in the BMP family.

  13. Hormonal and photoperiodic modulation of testicular mRNAs coding for inhibin/activin subunits and follistatin in Clethrionomys glareolus, Schreber.

    Science.gov (United States)

    Tähkä, K M; Kaipia, A; Toppari, J; Tähkä, S; Tuuri, T; Tuohimaa, P

    1998-07-01

    Photoperiodic and hormonal modulation of mRNAs for testicular inhibin/activin subunits and follistatin were studied in a seasonally breeding rodent, the bank vole (Clethrionomys glareolus). Photoperiod-induced testicular regression had no effect on the relatively low steady-state levels of follistatin mRNA. Inhibin alpha (I alpha) and beta B (I beta B) mRNA levels were significantly higher in regressed than in active gonads, but inhibin beta A was undetectable. The effect of gonadotropin administration on testicular weight and mRNA concentrations differed between the sexually active and quiescent voles. Neither FSH (1.2 U/kg; s.c. for 5 days) nor hCG (600 IU/kg; s.c. for 5 days) affected testicular weight in sexually active voles, whereas both gonadotropins significantly increased testicular weight in photo-regressed individuals. FSH had no effect on I alpha or I beta B mRNA concentrations in the active testes, whereas excessive hCG challenge induced a decrease in the steady-state levels of these mRNAs. FSH induced an increase in I alpha mRNA concentrations in the regressed gonad, whereas both gonadotropins concomitantly down-regulated I beta B mRNA levels. In conclusion, the high expression of I alpha and I beta B mRNA in the regressed testis imply autocrine and paracrine roles for inhibin/activin in the quiescent gonad of seasonal breeders. Inhibin alpha-subunit expression is at least partly under the control of FSH in the bank vole testis.

  14. Effects of c-Jun N-terminal kinase on Activin A/Smads signaling in PC12 cell suffered from oxygen-glucose deprivation.

    Science.gov (United States)

    Wang, J Q; Xu, Z H; Liang, W Z; He, J T; Cui, Y; Liu, H Y; Xue, L X; Shi, W; Shao, Y K; Mang, J; Xu, Z X

    2016-02-29

    Activin A (Act A), a member of transforming growth factor-β (TGF-β) superfamily, is an early gene in response to cerebral ischemia. Growing evidences confirm the neuroprotective effect of Act A in ischemic injury through Act A/Smads signal activation. In this process, regulation networks are involved in modulating the outcomes of Smads signaling. Among these regulators, crosstalk between c-Jun N-terminal kinase (JNK) and Smads signaling has been found in the TGF-β induced epithelial-mesenchymal transition. However, in neural ischemia, the speculative regulation between JNK and Act A/Smads signaling pathways has not been clarified. To explore this issue, an Oxygen Glucose Deprivation (OGD) model was introduced to nerve-like PC12 cells. We found that JNK signal activation occurred at the early time of OGD injury (1 h). Act A administration suppressed JNK phosphorylation. In addition, JNK inhibition could elevate the strength of Smads signaling and attenuate neural apoptosis after OGD injury. Our results indicated a negative regulation effect of JNK on Smads signaling in ischemic injury. Taken together, JNK, as a critical site for neural apoptosis and negative regulator for Act A/Smads signaling, was presumed to be a molecular therapeutic target for ischemia.

  15. Dual Inhibition of Activin/Nodal/TGF-β and BMP Signaling Pathways by SB431542 and Dorsomorphin Induces Neuronal Differentiation of Human Adipose Derived Stem Cells

    Directory of Open Access Journals (Sweden)

    Vedavathi Madhu

    2016-01-01

    Full Text Available Damage to the nervous system can cause devastating diseases or musculoskeletal dysfunctions and transplantation of progenitor stem cells can be an excellent treatment option in this regard. Preclinical studies demonstrate that untreated stem cells, unlike stem cells activated to differentiate into neuronal lineage, do not survive in the neuronal tissues. Conventional methods of inducing neuronal differentiation of stem cells are complex and expensive. We therefore sought to determine if a simple, one-step, and cost effective method, previously reported to induce neuronal differentiation of embryonic stem cells and induced-pluripotent stem cells, can be applied to adult stem cells. Indeed, dual inhibition of activin/nodal/TGF-β and BMP pathways using SB431542 and dorsomorphin, respectively, induced neuronal differentiation of human adipose derived stem cells (hADSCs as evidenced by formation of neurite extensions, protein expression of neuron-specific gamma enolase, and mRNA expression of neuron-specific transcription factors Sox1 and Pax6 and matured neuronal marker NF200. This process correlated with enhanced phosphorylation of p38, Erk1/2, PI3K, and Akt1/3. Additionally, in vitro subcutaneous implants of SB431542 and dorsomorphin treated hADSCs displayed significantly higher expression of active-axonal-growth-specific marker GAP43. Our data offers novel insights into cell-based therapies for the nervous system repair.

  16. In vivo amelioration of endogenous antitumor autoantibodies via low-dose P4N through the LTA4H/activin A/BAFF pathway.

    Science.gov (United States)

    Lin, Yu-Ling; Tsai, Nu-Man; Hsieh, Cheng-Hao; Ho, Shu-Yi; Chang, Jung; Wu, Hsin-Yi; Hsu, Ming-Hua; Chang, Chia-Ching; Liao, Kuang-Wen; Jackson, Tiffany L B; Mold, David E; Huang, Ru Chih C

    2016-11-29

    Cancer progression is associated with the development of antitumor autoantibodies in patients' sera. Although passive treatment with antitumor antibodies has exhibited remarkable therapeutic efficacy, inhibitory effects on tumor progression by endogenous antitumor autoantibodies (EAAs) have been limited. In this study, we show that P4N, a derivative of the plant lignan nordihydroguaiaretic acid (NDGA), enhanced the production of EAAs and inhibited tumor growth at low noncytotoxic concentrations via its immunoregulatory activity. Intratumoral injection of P4N improved the quantity and quality of EAAs, and passive transfer of P4N-induced EAAs dramatically suppressed lung metastasis formation and prolonged the survival of mice inoculated with metastatic CT26 tumor cells. P4N-induced EAAs specifically recognized two surface antigens, 78-kDa glucose-regulated protein (GRP78) and F1F0 ATP synthase, on the plasma membrane of cancer cells. Additionally, P4N treatment led to B-cell proliferation, differentiation to plasma cells, and high titers of autoantibody production. By serial induction of autocrine and paracrine signals in monocytes, P4N increased B-cell proliferation and antibody production via the leukotriene A4 hydrolase (LTA4H)/activin A/B-cell activating factor (BAFF) pathway. This mechanism provides a useful platform for studying and seeking a novel immunomodulator that can be applied in targeting therapy by improving the quantity and quality of the EAAs.

  17. bFGF and Activin A function to promote survival and proliferation of single iPS cells in conditioned half-exchange mTeSR1 medium.

    Science.gov (United States)

    Guo, Xiaoling; Lian, Ruiling; Guo, Yonglong; Liu, Qing; Ji, Qingshan; Chen, Jiansu

    2015-07-01

    Human induced pluripotent stem (iPS) cells can be well maintained by clonal growth. The pluripotent growth of single iPS cells is limited by low survival. To facilitate robust single iPS cells cultured in vitro, half-exchange mTeSR1 medium (HM), whole-exchange medium (WM) and iPS cell-derived conditioned medium (iPS-CM) culture were used. The effects of bFGF and Activin A on the growth of single iPS cells were explored. The dissociation and propagation of single iPS cells also included Accutase enzymatic isolation, Rho-associated protein kinase (ROCK) inhibitor Y27632 protection and high-density single-cell seeding (1 × 10(6) cells/well). CCK-8 assays demonstrated that the viability of clonal iPS cells in mTeSR1 medium and single iPS cells in HM, iPS-CM or WM supplemented with 100 ng/ml bFGF and 10 ng/ml Activin A was significantly higher than that in WM. Annexin v and propidium iodide (PI) assay, Calcein AM and EthD-III double staining also confirmed the similar results. ELISA assays showed that the levels of bFGF and Activin A of single iPS cells in HM and iPS-CM were higher than single iPS cells in WM. Meanwhile, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), quantitative Polymerase Chain Reaction (qPCR), Western Blotting (WB), Immunofluorescence (IF) and karyotype analysis revealed that HM culture was able to maintain undifferentiated markers of Nanog, Klf4, Sox2, Oct4, and did not affect the karyotype of iPS cells. Undifferentiated single iPS cells in HM displayed homogenized growth. These findings demonstrate that bFGF and Activin A are important for the survival and growth of single iPS cells. HM culture system combined Accutase, Y27632 and high-density single-cell seeding can facilitate short-term growth of single iPS cells in vitro.

  18. Multiple roles of Activin/Nodal, bone morphogenetic protein, fibroblast growth factor and Wnt/β-catenin signalling in the anterior neural patterning of adherent human embryonic stem cell cultures

    Science.gov (United States)

    Lupo, Giuseppe; Novorol, Claire; Smith, Joseph R.; Vallier, Ludovic; Miranda, Elena; Alexander, Morgan; Biagioni, Stefano; Pedersen, Roger A.; Harris, William A.

    2013-01-01

    Several studies have successfully produced a variety of neural cell types from human embryonic stem cells (hESCs), but there has been limited systematic analysis of how different regional identities are established using well-defined differentiation conditions. We have used adherent, chemically defined cultures to analyse the roles of Activin/Nodal, bone morphogenetic protein (BMP), fibroblast growth factor (FGF) and Wnt/β-catenin signalling in neural induction, anteroposterior patterning and eye field specification in hESCs. We show that either BMP inhibition or activation of FGF signalling is required for effective neural induction, but these two pathways have distinct outcomes on rostrocaudal patterning. While BMP inhibition leads to specification of forebrain/midbrain positional identities, FGF-dependent neural induction is associated with strong posteriorization towards hindbrain/spinal cord fates. We also demonstrate that Wnt/β-catenin signalling is activated during neural induction and promotes acquisition of neural fates posterior to forebrain. Therefore, inhibition of this pathway is needed for efficient forebrain specification. Finally, we provide evidence that the levels of Activin/Nodal and BMP signalling have a marked influence on further forebrain patterning and that constitutive inhibition of these pathways represses expression of eye field genes. These results show that the key mechanisms controlling neural patterning in model vertebrate species are preserved in adherent, chemically defined hESC cultures and reveal new insights into the signals regulating eye field specification. PMID:23576785

  19. The crucial role of Activin A on the formation of primordial germ cell-like cells from skin-derived stem cells in vitro.

    Science.gov (United States)

    Sun, Rui; Sun, Yuan-Chao; Ge, Wei; Tan, Hui; Cheng, Shun-Feng; Yin, Shen; Sun, Xiao-Feng; Li, Lan; Dyce, Paul; Li, Julang; Yang, Xiao; Shi, Qing-Hua; Shen, Wei

    2015-01-01

    Primordial germ cells (PGCs) are founder cells of the germ cell lineage, and can be differentiated from stem cells in an induced system in vitro. However, the induction conditions need to be optimized in order to improve the differentiation efficiency. Activin A (ActA) is a member of the TGF-β super family and plays an important role in oogenesis and folliculogenesis. In the present study, we found that ActA promoted PGC-like cells (PGCLCs) formation from mouse skin-derived stem cells (SDSCs) in both embryoid body-like structure (EBLS) differentiation and the co-culture stage in a dose dependent manner. ActA treatment (100 ng/ml) during EBLS differentiation stage and further co-cultured for 6 days without ActA significantly increased PGCLCs from 53.2% to 82.8%, and as well as EBLS differentiation without ActA followed by co-cultured with 100 ng/ml ActA for 4 to 12 days with the percentage of PGCLCs increasing markedly in vitro. Moreover, mice treated with ActA at 100 ng/kg body weight from embryonic day (E) 5.5-12.5 led to more PGCs formation. However, the stimulating effects of ActA were interrupted by Smad3 RNAi, and in an in vitro cultured Smad3(-/-) mouse skin cells scenario. SMAD3 is thus likely a key effecter molecule in the ActA signaling pathway. In addition, we found that the expression of some epiblast cell markers, Fgf5, Dnmt3a, Dnmt3b and Wnt3, was increased in EBLSs cultured for 4 days or PGCLCs co-cultured for 12 days with ActA treatment. Interestingly, at 16 days of differentiation, the percentage of PGCLCs was decreased in the presence of ActA, but the expression of meiosis-relative genes, such as Stra8, Dmc1, Sycp3 and Sycp1, was increased. In conclusion, our data here demonstrated that ActA can promote PGCLC formation from SDSCs in vitro, at early stages of differentiation, and affect meiotic initiation of PGCLCs in later stages.

  20. Expressions of Placenta Inhibin-A, Activin-A and Inhibin-B Genes in Preeclamptic Pregnancy%子痫前期胎盘抑制素A、胎盘激活素A和胎盘抑制素B基因的表达

    Institute of Scientific and Technical Information of China (English)

    董旭东; 吴云萍; 江江; 陈桂仙

    2011-01-01

    Objective: To investigate the mRNA expression and the significance of inhibin-A,activin-A and inhibin-B subunites in the placenta from preeclamptic patients.Methods: The mRNA levels of inhibin-A, activin-A and inhibin-B subunites in the placenta from 44 pre-eclamptic patients and 30 normal pregnancies were measured by RT-PCR.Results: The mRNA levels of inhibin-A α-βA subunite and activin-A βA-βA subunite in the placentas from pre-eclamptic patients were significantly higher than those in the placenta from normal pregnancies (P < 0.05 ), while the mRNA expression of inhibin-B α-βB subunit between the preeclamptic and normal pregnancy groups were no significant difference( P>0.05).Conclutions: The mRNA levels of inhibin-A α-βA subunite and activin-A βA-βA subunite increased significantly in the placenta from pre-eclamptic patients.The levels of inhibin-A and activin-A can reflect the function of trophoblastic cells, so they could be useful markers to monitor the function of placenta, and involve in the pathophysiologic process of preeclampsia.%目的:探讨子痫前期患者胎盘中抑制素A(inhibin-A)、激活素A(activin-A)和抑制素B(inhibin-B)亚单位基因的表达水平及其意义.方法:采用逆转录聚合酶链反应(RT-PCR)技术定量测定44例子痫前期患者和30例正常妊娠妇女胎盘中inhibin-A、activin-A和inhibin-B亚单位基因mRNA的表达.结果:子痫前期组胎盘中inhibin-A a-βA亚单位和activin-A βA-βA亚单位基因mRNA表达水平明显高于对照组,差异有统计学意义(P0.05).结论:子痫前期患者胎盘中的inhibin-A a-βA亚单位和activin-A βA-βA亚单位mRNA表达水平升高,inhibin-A/activin-A水平可反映滋养细胞的功能,是监测胎盘功能有效指标,并参与子痫前期的病理生理过程.

  1. Toward a better understanding of the interaction between TGF-β family members and their ALK receptors

    KAUST Repository

    Romano, Valentina

    2012-02-22

    Transforming growth factor-beta (TGF-β) proteins are a family of structurally related extracellular proteins that trigger their signaling functions through interaction with the extracellular domains of their cognate serine/threonine kinase receptors. The specificity of TGF-β/receptor binding is complex and gives rise to multiple functional roles. Additionally, it is not completely understood at the atomic level. Here, we use the most reliable computational methods currently available to study systems involving activin-like kinase (ALK) receptors ALK4 and ALK7 and their multiple TGF-β ligands. We built models for all these proteins and their complexes for which experimental structures are not available. By analyzing the surfaces of interaction in six different TGF-β/ALK complexes we could infer which are the structural distinctive features of the ligand-receptor binding mode. Furthermore, this study allowed us to rationalize why binding of the growth factors GDF3 and Nodal to the ALK4 receptor requires the Cripto co-factor, whilst binding to the ALK7 receptor does not. © Springer-Verlag 2012.

  2. Activin receptor-like kinase receptors ALK5 and ALK1 are both required for TGFβ-induced chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells

    NARCIS (Netherlands)

    L.M.G. De Kroon (Laurie); R. Narcisi (Roberto); E.N. Blaney Davidson (Esmeralda); M.A. Cleary (Mairéad); H.M. van Beuningen (Henk); W.J.L.M. Koevoet (Wendy J.L.M.); G.J.V.M. van Osch (Gerjo); P.M. van der Kraan (Peter)

    2015-01-01

    textabstractIntroduction Bone marrow-derived mesenchymal stem cells (BMSCs) are promising for cartilage regeneration because BMSCs can differentiate into cartilage tissue-producing chondrocytes. Transforming Growth Factor beta; (TGFbeta;) is crucial for inducing chondrogenic differentiation of BMSCs

  3. Somatostatin receptors

    DEFF Research Database (Denmark)

    Møller, Lars Neisig; Stidsen, Carsten Enggaard; Hartmann, Bolette

    2003-01-01

    therefore been acknowledged to be a third endogenous ligand at SRIF receptors. This review goes through mechanisms of signal transduction, pharmacology, and anatomical distribution of SRIF receptors. Structurally, SRIF receptors belong to the superfamily of G protein-coupled (GPC) receptors, sharing....... The generation of knock-out (KO) mice, intended as a means to define the contributions made by individual receptor subtypes, necessarily marks but an approximation. Furthermore, we must now take into account the stunning complexity of receptor co-operation indicated by the observation of receptor homo......-peptides, receptor agonists and antagonists. Relatively long half lives, as compared to those of the endogenous ligands, have been paramount from the outset. Motivated by theoretical puzzles or the shortcomings of present-day diagnostics and therapy, investigators have also aimed to produce subtype...

  4. Diagnostic value of serum activin A and follistatin levels indifferent types of endometriosis%激活素A和卵泡抑素在子宫内膜异位症中的诊断价值

    Institute of Scientific and Technical Information of China (English)

    徐小艳; 洛若愚; 邢辉

    2015-01-01

    目的:探讨人激活素 A 和卵泡抑素在腹膜型,卵巢型及深部浸润型子宫内膜异位症中的临床诊断价值。方法子宫内膜异位症患者139例,分成腹膜型内异症组28例,卵巢型内异症组61例,深部浸润型内异症组50例,月经规律的健康女性(对照组)75例,均采集外周静脉血,采用酶联免疫测定试剂盒分析血清中激活素A 和卵泡抑素。结果卵巢内异症组激活素 A 水平[(0.22±0.01)ng/ml]明显高于对照组[(0.17±0.01)ng/ml]、腹膜型内异症组[(0.19±0.01)ng/ml]及深部浸润型内异症组[(0.16±0.02)ng/ml],差异有统计学意义;子宫内膜异位症患者卵泡抑素与对照组比较,差异无统计学意义;深部浸润型内异症组卵泡抑素水平[(1.50±0.17)ng/ml]低于腹膜型内异症组[(2.24±0.42)ng/ml]和卵巢内异症组[(2.34±0.32)ng/ml],差异有统计学意义;激活素 A和卵泡抑素诊断卵巢内异症的 ROC 曲线下面积分别为0.700(95% CI 为0.605~0.794)和0.620(95% CI 为0.510~0.730),二者联合应用不能提高子宫内膜异位症的诊断特异度和灵敏度。结论激活素 A 和卵泡抑素水平在腹膜型内异症和深部浸润型内异症中无明显改变,对诊断卵巢型内异症的准确率有限。%Objective To explore the clinical value of activin A and follistatin levels in women with peritoneal, ovarian and deep inltrating endometriosis. Methods One hundred and thirty﹣nine patients with endometriosis were divided into three groups:peritoneal endometriosis (n =28),ovarian endometrioma (n =61 ),and deep inltrating endometriosis (n =50).Seventy﹣five health women were included as the control group.Peripheral vein blood samples were collected for activin A and follistatin assessment by enzyme immunoassay kits. Results The ovarian endometrioma group [(0.22 ±0.01)ng/ml]had serum

  5. The Xenopus receptor tyrosine kinase Xror2 modulates morphogenetic movements of the axial mesoderm and neuroectoderm via Wnt signaling.

    Science.gov (United States)

    Hikasa, Hiroki; Shibata, Mikihito; Hiratani, Ichiro; Taira, Masanori

    2002-11-01

    The Spemann organizer plays a central role in neural induction, patterning of the neuroectoderm and mesoderm, and morphogenetic movements during early embryogenesis. By seeking genes whose expression is activated by the organizer-specific LIM homeobox gene Xlim-1 in Xenopus animal caps, we isolated the receptor tyrosine kinase Xror2. Xror2 is expressed initially in the dorsal marginal zone, then in the notochord and the neuroectoderm posterior to the midbrain-hindbrain boundary. mRNA injection experiments revealed that overexpression of Xror2 inhibits convergent extension of the dorsal mesoderm and neuroectoderm in whole embryos, as well as the elongation of animal caps treated with activin, whereas it does not appear to affect cell differentiation of neural tissue and notochord. Interestingly, mutant constructs in which the kinase domain was point-mutated or deleted (named Xror2-TM) also inhibited convergent extension, and did not counteract the wild-type, suggesting that the ectodomain of Xror2 per se has activities that may be modulated by the intracellular domain. In relation to Wnt signaling for planar cell polarity, we observed: (1) the Frizzled-like domain in the ectodomain is required for the activity of wild-type Xror2 and Xror2-TM; (2) co-expression of Xror2 with Xwnt11, Xfz7, or both, synergistically inhibits convergent extension in embryos; (3) inhibition of elongation by Xror2 in activin-treated animal caps is reversed by co-expression of a dominant negative form of Cdc42 that has been suggested to mediate the planar cell polarity pathway of Wnt; and (4) the ectodomain of Xror2 interacts with Xwnts in co-immunoprecipitation experiments. These results suggest that Xror2 cooperates with Wnts to regulate convergent extension of the axial mesoderm and neuroectoderm by modulating the planar cell polarity pathway of Wnt.

  6. Transforming growth factor β receptor type 1 is essential for female reproductive tract integrity and function.

    Directory of Open Access Journals (Sweden)

    Qinglei Li

    2011-10-01

    Full Text Available The transforming growth factor β (TGFβ superfamily proteins are principle regulators of numerous biological functions. Although recent studies have gained tremendous insights into this growth factor family in female reproduction, the functions of the receptors in vivo remain poorly defined. TGFβ type 1 receptor (TGFBR1, also known as activin receptor-like kinase 5, is the major type 1 receptor for TGFβ ligands. Tgfbr1 null mice die embryonically, precluding functional characterization of TGFBR1 postnatally. To study TGFBR1-mediated signaling in female reproduction, we generated a mouse model with conditional knockout (cKO of Tgfbr1 in the female reproductive tract using anti-Müllerian hormone receptor type 2 promoter-driven Cre recombinase. We found that Tgfbr1 cKO females are sterile. However, unlike its role in growth differentiation factor 9 (GDF9 signaling in vitro, TGFBR1 seems to be dispensable for GDF9 signaling in vivo. Strikingly, we discovered that the Tgfbr1 cKO females develop oviductal diverticula, which impair embryo development and transit of embryos to the uterus. Molecular analysis further demonstrated the dysregulation of several cell differentiation and migration genes (e.g., Krt12, Ace2, and MyoR that are potentially associated with female reproductive tract development. Moreover, defective smooth muscle development was also revealed in the uteri of the Tgfbr1 cKO mice. Thus, TGFBR1 is required for female reproductive tract integrity and function, and disruption of TGFBR1-mediated signaling leads to catastrophic structural and functional consequences in the oviduct and uterus.

  7. Transforming Growth Factor β Receptor Type 1 Is Essential for Female Reproductive Tract Integrity and Function

    Science.gov (United States)

    Li, Qinglei; Agno, Julio E.; Edson, Mark A.; Nagaraja, Ankur K.; Nagashima, Takashi; Matzuk, Martin M.

    2011-01-01

    The transforming growth factor β (TGFβ) superfamily proteins are principle regulators of numerous biological functions. Although recent studies have gained tremendous insights into this growth factor family in female reproduction, the functions of the receptors in vivo remain poorly defined. TGFβ type 1 receptor (TGFBR1), also known as activin receptor-like kinase 5, is the major type 1 receptor for TGFβ ligands. Tgfbr1 null mice die embryonically, precluding functional characterization of TGFBR1 postnatally. To study TGFBR1–mediated signaling in female reproduction, we generated a mouse model with conditional knockout (cKO) of Tgfbr1 in the female reproductive tract using anti-Müllerian hormone receptor type 2 promoter-driven Cre recombinase. We found that Tgfbr1 cKO females are sterile. However, unlike its role in growth differentiation factor 9 (GDF9) signaling in vitro, TGFBR1 seems to be dispensable for GDF9 signaling in vivo. Strikingly, we discovered that the Tgfbr1 cKO females develop oviductal diverticula, which impair embryo development and transit of embryos to the uterus. Molecular analysis further demonstrated the dysregulation of several cell differentiation and migration genes (e.g., Krt12, Ace2, and MyoR) that are potentially associated with female reproductive tract development. Moreover, defective smooth muscle development was also revealed in the uteri of the Tgfbr1 cKO mice. Thus, TGFBR1 is required for female reproductive tract integrity and function, and disruption of TGFBR1–mediated signaling leads to catastrophic structural and functional consequences in the oviduct and uterus. PMID:22028666

  8. Lipoxin Receptors

    Directory of Open Access Journals (Sweden)

    Mario Romano

    2007-01-01

    Full Text Available Lipoxins (LXs represent a class of arachidonic acid (AA metabolites that carry potent immunoregulatory and anti-inflammatory properties, LXA4 and LXB4 being the main components of this series. LXs are generated by cooperation between 5-lipoxygenase (LO and 12- or 15-LO during cell-cell interactions or by single cell types. LX epimers at carbon 15, the 15-epi-LXs, are formed by aspirin-acetylated cyclooxygenase-2 (COX-2 in cooperation with 5-LO. 15-epi-LXA4 is also termed aspirin-triggered LX (ATL. In vivo studies with stable LX and ATL analogs have established that these eicosanoids possess potent anti-inflammatory activities. A LXA4 receptor has been cloned. It belongs to the family of chemotactic receptors and clusters with formyl peptide receptors on chromosome 19. Therefore, it was initially denominated formyl peptide receptor like 1 (FPRL1. This receptor binds with high affinity and stereoselectivity LXA4 and ATL. It also recognizes a variety of peptides, synthetic, endogenously generated, or disease associated, but with lower affinity compared to LXA4. For this reason, this receptor has been renamed ALX. This review summarizes the current knowledge on ALX expression, signaling, and potential pathophysiological role. The involvement of additional recognition sites in LX bioactions is also discussed.

  9. Circulating irisin levels are lower in patients with either stable coronary artery disease (CAD) or myocardial infarction (MI) versus healthy controls, whereas follistatin and activin A levels are higher and can discriminate MI from CAD with similar to CK-MB accuracy.

    Science.gov (United States)

    Anastasilakis, Athanasios D; Koulaxis, Dimitrios; Kefala, Nikoleta; Polyzos, Stergios A; Upadhyay, Jagriti; Pagkalidou, Eirini; Economou, Fotios; Anastasilakis, Chrysostomos D; Mantzoros, Christos S

    2017-08-01

    Several myokines are produced by cardiac muscle. We investigated changes in myokine levels at the time of acute myocardial infarction (MI) and following reperfusion in relation to controls. Patients with MI (MI Group, n=31) treated with percutaneous coronary intervention (PCI) were compared to patients with stable coronary artery disease (CAD) subjected to scheduled PCI (CAD Group, n=40) and controls with symptoms mimicking CAD without stenosis in angiography (Control Group, n=43). The number and degree of stenosis were recorded. Irisin, follistatin, follistatin-like 3, activin A and B, ALT, AST, CK and CK-MB were measured at baseline and 6 or 24h after the intervention. MI and CAD patients had lower irisin than controls (pCAD patients and controls (all p≤0.001). None of the myokines changed following reperfusion. Circulating irisin was associated with the degree of stenosis in all patients (p=0.05). Irisin was not inferior to CK-MB in predicting MI while folistatin and activin A could discriminate MI from CAD patients with similar to CK-MB accuracy. None of these myokines was altered following PCI in contrast to CK-MB. Irisin levels are lower in MI and CAD implying that their production may depend on myocadial blood supply. Follistatin and activin A are higher in MI than in CAD suggesting increased release due to myocardial necrosis. They can predict MI with accuracy similar to CK-MB and their role in the diagnosis of MI remains to be confirmed by prospective large clinical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. 激活素A对Neuro-2a细胞电压门控钠电流的作用%Effects of activin A on voltage-gated Na+ current of Neuro-2a cells

    Institute of Scientific and Technical Information of China (English)

    孙洋; 柳忠辉; 王轶楠; 刘海岩; 王东辉; 葛敬岩

    2010-01-01

    目的:研究激活素A(activin A)对Neuro-2a细胞电压门控钠电流(INa)的作用及其机制,为激活素A在神经系统疾病中的应用奠定基础.方法:培养小鼠源性Neuro-2a细胞,分为IgG对照组和抗激活素受体ⅡA (ActRⅡA)抗体染色组,免疫组织化学染色观察ActRⅡA在Neuro-2a细胞中是否表达;将Neuro-2a细胞随机分为正常对照组和激活素A组,采用全细胞膜片钳技术检测激活素A对Neuro-2a细胞 INa 的作用;采用RT-PCR检测激活素A对血管活性肠肽(VIP)及诱导型一氧化氮合酶(iNOS) mRNA表达的影响.结果:正常Neuro-2a细胞中可检测到ActRⅡA的表达;与正常对照组比较,激活素A明显增加Neuro-2a细胞INa(P< 0.05);激活素A组Neuro-2a细胞VIP mRNA表达明显高于正常对照组(P< 0.05),而iNOS mRNA表达低于正常对照组(P<0.05).结论:激活素A具有增加Neuro-2a细胞电压门控Na+电流的作用,VIP和iNOS途径可能参与了激活素A调控神经细胞的功能.

  11. 激活素受体样激酶1促进人脐静脉内皮细胞增殖和迁徙%The activin receptor-like kinase I promotes proliferation and migration in HUVECs

    Institute of Scientific and Technical Information of China (English)

    李斌; 唐仕波; 林少芬; 孟晶

    2006-01-01

    目的:研究激活素受体样激酶1(ALK1)对人脐静脉内皮细胞的作用.方法:体外培养人脐静脉内皮细胞(HUVECs),RT-PCR分析ALK1和ALK5在HUVEC激活状态下表达的变化.脂质体转染pcDNA3.1+ALK1到HUVECs,流式细胞仪检测HUVECs增殖的改变,boyden小室检测ALK1对HUVECs迁徙的影响.结果:ALK1在HUVEC安静状态高表达,ALK1能促进HUVECs的增殖和迁徙.结论:ALK1通过促进内皮细胞的增殖和迁徙在血管重塑中发挥作用.

  12. Induction of transforming growth factor beta receptors following focal ischemia in the rat brain.

    Directory of Open Access Journals (Sweden)

    Gabriella Pál

    Full Text Available Transforming growth factor-βs (TGF-βs regulate cellular proliferation, differentiation, and survival. TGF-βs bind to type I (TGF-βRI and II receptors (TGF-βRII, which are transmembrane kinase receptors, and an accessory type III receptor (TGF-βRIII. TGF-β may utilize another type I receptor, activin-like kinase receptor (Alk1. TGF-β is neuroprotective in the middle cerebral artery occlusion (MCAO model of stroke. Recently, we reported the expression pattern of TGF-β1-3 after MCAO. To establish how TGF-βs exert their actions following MCAO, the present study describes the induction of TGF-βRI, RII, RIII and Alk1 at 24 h, 72 h and 1 mo after transient 1 h MCAO as well as following 24 h permanent MCAO using in situ hybridization histochemistry. In intact brain, only TGF-βRI had significant expression: neurons in cortical layer IV contained TGF-βRI. At 24 h after the occlusion, no TGF-β receptors showed induction. At 72 h following MCAO, all four types of TGF-β receptors were induced in the infarct area, while TGF-βRI and RII also appeared in the penumbra. Most cells with elevated TGF-βRI mRNA levels were microglia. TGF-βRII co-localized with both microglial and endothelial markers while TGF-βRIII and Alk1 were present predominantly in endothels. All four TGF-β receptors were induced within the lesion 1 mo after the occlusion. In particular, TGF-βRIII was further induced as compared to 72 h after MCAO. At this time point, TGF-βRIII signal was predominantly not associated with blood vessels suggesting its microglial location. These data suggest that TGF-β receptors are induced after MCAO in a timely and spatially regulated fashion. TGF-β receptor expression is preceded by increased TGF-β expression. TGF-βRI and RII are likely to be co-expressed in microglial cells while Alk1, TGF-βRII, and RIII in endothels within the infarct where TGF-β1 may be their ligand. At later time points, TGF-βRIII may also appear in glial cells

  13. Opioid Receptors.

    Science.gov (United States)

    Stein, Christoph

    2016-01-01

    Opioids are the oldest and most potent drugs for the treatment of severe pain. Their clinical application is undisputed in acute (e.g., postoperative) and cancer pain, but their long-term use in chronic pain has met increasing scrutiny. This article reviews mechanisms underlying opioid analgesia and other opioid actions. It discusses the structure, function, and plasticity of opioid receptors; the central and peripheral sites of analgesic actions and side effects; endogenous and exogenous opioid receptor ligands; and conventional and novel opioid compounds. Challenging clinical situations, such as the tension between chronic pain and addiction, are also illustrated.

  14. The structure of myostatin:follistatin 288: insights into receptor utilization and heparin binding

    Energy Technology Data Exchange (ETDEWEB)

    Cash, Jennifer N.; Rejon, Carlis A.; McPherron, Alexandra C.; Bernard, Daniel J.; Thompson, Thomas B.; (UCIN); (McGill); (NIH)

    2009-09-29

    Myostatin is a member of the transforming growth factor-{beta} (TGF-{beta}) family and a strong negative regulator of muscle growth. Here, we present the crystal structure of myostatin in complex with the antagonist follistatin 288 (Fst288). We find that the prehelix region of myostatin very closely resembles that of TGF-{beta} class members and that this region alone can be swapped into activin A to confer signalling through the non-canonical type I receptor Alk5. Furthermore, the N-terminal domain of Fst288 undergoes conformational rearrangements to bind myostatin and likely acts as a site of specificity for the antagonist. In addition, a unique continuous electropositive surface is created when myostatin binds Fst288, which significantly increases the affinity for heparin. This translates into stronger interactions with the cell surface and enhanced myostatin degradation in the presence of either Fst288 or Fst315. Overall, we have identified several characteristics unique to myostatin that will be paramount to the rational design of myostatin inhibitors that could be used in the treatment of muscle-wasting disorders.

  15. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy

    Science.gov (United States)

    Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A.; Leyton, Patricio A.; Cheng, Juan; Tainsh, Robert E. T.; Mayeur, Claire; Rhee, David K.; Wu, Mei. X.; Scherrer-Crosbie, Marielle; Buys, Emmanuel S.; Zapol, Warren M.; Bloch, Kenneth D.; Bloch, Donald B.

    2016-01-01

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis. PMID:26873969

  16. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy.

    Science.gov (United States)

    Shahid, Mohd; Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A; Leyton, Patricio A; Cheng, Juan; Tainsh, Robert E T; Mayeur, Claire; Rhee, David K; Wu, Mei X; Scherrer-Crosbie, Marielle; Buys, Emmanuel S; Zapol, Warren M; Bloch, Kenneth D; Bloch, Donald B

    2016-04-15

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis.

  17. The androgen receptor and estrogen receptor

    NARCIS (Netherlands)

    Oosterkamp, H.M.; Bernards, R.A.

    2002-01-01

    The androgen receptor (AR) and the estrogen receptors (ER) are members of the nuclear receptor (NR) family. These NRs are distinguished from the other transcription factors by their ability to control gene expression upon ligand binding (steroids, retinoids, thyroid hormone, vitamin D, fatty acids,

  18. GLP-1 Receptor Agonists

    Science.gov (United States)

    ... in Balance › GLP-1 Receptor Agonists Fact Sheet GLP-1 Receptor Agonists May, 2012 Download PDFs English Espanol Editors Silvio ... are too high or too low. What are GLP-1 receptor agonist medicines? GLP-1 receptor agonist medicines, also called ...

  19. The GnRH receptor and the response of gonadotrope cells to GnRH pulse frequency code. A story of an atypical adaptation of cell function relying on a lack of receptor homologous desensitization.

    Directory of Open Access Journals (Sweden)

    Christian Bleux

    2010-01-01

    Full Text Available Brain control of the reproductive system is mediated through hypothalamic gonadotropin-releasing hormone (GnRH which activates specific receptors (GnRHR present at the surface of the pituitary gonadotropes to trigger secretion of the two gonadotropins LH and FSH. A unique feature of this system is the high dependence on the secretion mode of GnRH, which is basically pulsatile but undergoes considerable fluctuations in pulse frequency pattern in response to endogenous or external factors. How the physiological fluctuations of GnRH secretion that orchestrate normal reproduction are decoded by the gonadotrope cell machinery to ultimately control gonadotropin release and/or subunit gene transcription has been the subject of intensive studies during the past decades. Surprisingly, the mammalian GnRHR is unique among G protein-coupled receptor family as it lacks the carboxy-terminal tail usually involved in classical endocytotic process. Accordingly, it does not desensitize properly and internalizes very poorly. Both this atypical intrinsic property and post-receptor events may thus contribute to decode the GnRH signal. This includes the participation of a network of signaling pathways that differently respond to GnRH together with a growing amount of genes differentially sensitive to pulse frequency. Among these are two pairs of genes, the transcription factors EGR-1 and NAB, and the regulatory factors activin and follistatin, that function as intracellular autoregulatory feedback loops controlling respectively LHbeta and FSHbeta gene expression and hence, LH and FSH synthesis. Pituitary gonadotropes thus represent a unique model of cells functionally adapted to respond to a considerably fluctuating neuroendocrine stimulation, from short individual pulses to sustained GnRH as observed at the proestrus of ovarian cycle. Altogether, the data emphasize the adaptative reciprocal complementarity of hypothalamic GnRH neurones and pituitary gonadotropes to

  20. Identification of TGF-β receptor-1 as a key regulator of carbon nanotube-induced fibrogenesis.

    Science.gov (United States)

    Mishra, Anurag; Stueckle, Todd A; Mercer, Robert R; Derk, Raymond; Rojanasakul, Yon; Castranova, Vincent; Wang, Liying

    2015-10-15

    Carbon nanotubes (CNTs) induce rapid interstitial lung fibrosis, but the underlying mechanisms are unclear. Previous studies indicated that the ability of CNTs to penetrate lung epithelium, enter interstitial tissue, and stimulate fibroblasts to produce collagen matrix is important to lung fibrosis. In this study, we investigated the activation of transforming growth factor-β receptor-1 [TGF-β R1; i.e., activin receptor-like kinase 5 (ALK5) receptor] and TGF-β/Smad signaling pathway in CNT-induced collagen production in human lung fibroblasts. Human lung fibroblasts and epithelial cells were exposed to low, physiologically relevant concentrations (0.02-0.6 μg/cm(2)) of single-walled CNTs (SWCNT) and multiwalled CNTs (MWCNT) in culture and analyzed for collagen, TGF-β1, TGF-β R1, and SMAD proteins by Western blotting and immunofluorescence. Chemical inhibition of ALK5 and short-hairpin (sh) RNA targeting of TGF-β R1 and Smad2 were used to probe the fibrogenic mechanism of CNTs. Both SWCNT and MWCNT induced an overexpression of TGF-β1, TGF-β R1 and Smad2/3 proteins in lung fibroblasts compared with vehicle or ultrafine carbon black-exposed controls. SWCNT- and MWCNT-induced collagen production was blocked by ALK5 inhibitor or shRNA knockdown of TGF-β R1 and Smad2. Our results indicate the critical role of TGF-β R1/Smad2/3 signaling in CNT-induced fibrogenesis by upregulating collagen production in lung fibroblasts. This novel finding may aid in the design of mechanism-based risk assessment and development of rapid screening tests for nanomaterial fibrogenicity.

  1. Transforming growth factor-beta type 1 receptor (ALK5) and Smad proteins mediate TIMP-1 and collagen synthesis in experimental intestinal fibrosis.

    Science.gov (United States)

    Medina, Carlos; Santos-Martinez, Maria Jose; Santana, Alfredo; Paz-Cabrera, Maria Cristina; Johnston, Michael J; Mourelle, Marisabel; Salas, Antonio; Guarner, Francisco

    2011-08-01

    Transforming growth factor β (TGF-β) is known to play a key role in intestinal fibrosis; however, the underlying mechanisms are not well understood. TGF-β signal transduction is through TGF-β receptors, including the TGF-β type 1 receptor. Most cell types contain a TGF-β type 1 receptor form known as activin receptor-like kinase 5 (ALK5), which propagates the signal to the nucleus through the phosphorylation of Smad2 and Smad3 proteins. Therefore, we assessed the effect of the disruption of TGF-β/ALK5/Smad signalling by an ALK5 inhibitor (SD-208) in two experimental animal models of intestinal fibrosis: anaerobic bacteria- and trinitrobenzensulphonic acid-induced colitis. In addition, isolated myofibroblasts were pretreated with SD-208 and exposed to recombinant TGF-β1. Finally, myofibroblasts were transfected with ALK5, Smad2, and Smad3-specific siRNA. Up-regulation of ALK5 and TIMP-1, phosphorylation of Smad2 and Smad3 proteins, and increased intestinal wall collagen deposition were found in both experimental animal models. These effects were decreased by SD-208. TGF-β1 treatment also induced phosphorylation of Smad2 and Smad3 and up-regulation of ALK5 protein, TIMP-1, and α2 type 1 collagen gene expression in isolated myofibroblasts. Again these effects were inhibited by SD-208. Also, ALK5, Smad2, and Smad3 siRNA abolished the induction of TIMP-1 and α2 type 1 collagen. Our findings provide evidence that the TGF-β/ALK5/Smad pathway participates in the pathogenesis of experimental intestinal fibrosis. These data show promise for the development of an effective therapeutic intervention in this condition.

  2. Acetylcholine receptor antibody

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003576.htm Acetylcholine receptor antibody To use the sharing features on this page, please enable JavaScript. Acetylcholine receptor antibody is a protein found in the blood ...

  3. Androgen receptor abnormalities

    NARCIS (Netherlands)

    A.O. Brinkmann (Albert); G.G.J.M. Kuiper (George); C. Ris-Stalpers (Carolyn); H.C.J. van Rooij (Henri); G. Romalo (G.); G. Trifiro (Gianluca); E. Mulder (Eppo); L. Pinsky (L.); H.U. Schweikert (H.); J. Trapman (Jan)

    1991-01-01

    markdownabstract__Abstract__ The human androgen receptor is a member of the superfamily of steroid hormone receptors. Proper functioning of this protein is a prerequisite for normal male sexual differentiation and development. The cloning of the human androgen receptor cDNA and the elucidation of t

  4. Mammalian Sweet Taste Receptors

    National Research Council Canada - National Science Library

    Nelson, Greg; Hoon, Mark A; Chandrashekar, Jayaram; Zhang, Yifeng; Ryba, Nicholas J.P; Zuker, Charles S

    2001-01-01

    ... and information coding, and have focused on the isolation and characterization of genes encoding sweet and bitter taste receptors. The identification of taste receptors generates powerful molecular tools to investigate not only the function of taste receptor cells, but also the logic of taste coding. For example, defining the size and diversity of the re...

  5. [Melatonin receptor agonist].

    Science.gov (United States)

    Uchiyama, Makoto

    2015-06-01

    Melatonin is a hormone secreted by the pineal gland and is involved in the regulation of human sleep-wake cycle and circadian rhythms. The melatonin MT1 and MT2 receptors located in the suprachiasmatic nucleus in the hypothalamus play a pivotal role in the sleep-wake regulation. Based on the fact that MT1 receptors are involved in human sleep onset process, melatonin receptor agonists have been developed to treat insomnia. In this article, we first reviewed functions of melatonin receptors with special reference to MT1 and MT2, and properties and clinical application of melatonin receptor agonists as hypnotics.

  6. Dopamine receptors and hypertension.

    Science.gov (United States)

    Banday, Anees Ahmad; Lokhandwala, Mustafa F

    2008-08-01

    Dopamine plays an important role in regulating renal function and blood pressure. Dopamine synthesis and dopamine receptor subtypes have been shown in the kidney. Dopamine acts via cell surface receptors coupled to G proteins; the receptors are classified via pharmacologic and molecular cloning studies into two families, D1-like and D2-like. Two D1-like receptors cloned in mammals, the D1 and D5 receptors (D1A and D1B in rodents), are linked to adenylyl cyclase stimulation. Three D2-like receptors (D2, D3, and D4) have been cloned and are linked mainly to adenylyl cyclase inhibition. Activation of D1-like receptors on the proximal tubules inhibits tubular sodium reabsorption by inhibiting Na/H-exchanger and Na/K-adenosine triphosphatase activity. Reports exist of defective renal dopamine production and/or dopamine receptor function in human primary hypertension and in genetic models of animal hypertension. In humans with essential hypertension, renal dopamine production in response to sodium loading is often impaired and may contribute to hypertension. A primary defect in D1-like receptors and an altered signaling system in proximal tubules may reduce dopamine-mediated effects on renal sodium excretion. The molecular basis for dopamine receptor dysfunction in hypertension is being investigated, and may involve an abnormal posttranslational modification of the dopamine receptor.

  7. GABA receptor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Doo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABA{sub A}-receptor that allows chloride to pass through a ligand gated ion channel and GABA{sub B}-receptor that uses G-proteins for signaling. The GABA{sub A}-receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABA{sub A}-receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with {sup 11}C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, {sup 18}F-fluoroflumazenil (FFMZ) has been developed to overcome {sup 11}C's short half-life. {sup 18}F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '1{sup 1}C-FMZ PET instead of {sup 18}F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABA{sub A} receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas.

  8. TGF-β1 exerts opposing effects on grass carp leukocytes: implication in teleost immunity, receptor signaling and potential self-regulatory mechanisms.

    Directory of Open Access Journals (Sweden)

    Mu Yang

    Full Text Available In fish immunity, the regulatory role of transforming growth factor-β1 (TGF-β1 has not been fully characterized. Here we examined the immunoregulatory effects of TGF-β1 in grass carp peripheral blood leukocytes (PBL and head kidney leukocytes (HKL. It is interesting that TGF-β1 consistently stimulated the cell viability and the mRNA levels of pro-inflammatory cytokines (Tnfα and Ifnγ and T/B cell markers [Cd4-like (Cd4l, Cd8α, Cd8β and Igμ] in PBL, which contrasted with its inhibitory tone in HKL. Further studies showed that grass carp TGF-β1 type I receptor, activin receptor-like kinase 5 (ALK5, was indispensable for the immunoregulatory effects of TGF-β1 in PBL and HKL. Notably, TGF-β1 persistently attenuated ALK5 expression, whereas immunoneutralization of endogenous grass carp TGF-β1 could increase ALK5 mRNA and protein levels. It is consistent with the observation that TGF-β1 decreased the number of ALK5(+ leukocytes in PBL and HKL, revealing a negative regulation of TGF-β1 signaling at the receptor level. Moreover, transient treatment with TGF-β1 for 24 h was sufficient to induce similar cellular responses compared with the continuous treatment. This indicated a possible mechanism by which TGF-β1 triggered the down-regulation of ALK5 mRNA and protein, leading to the desensitization of grass carp leukocytes toward TGF-β1. Accordingly, our data revealed a dual role of TGF-β1 in teleost immunity in which it can serve as a positive or negative control device and provided additional mechanistic insights as to how TGF-β1 controls its signaling in vertebrate leukocytes.

  9. Chicken NK cell receptors.

    Science.gov (United States)

    Straub, Christian; Neulen, Marie-Luise; Sperling, Beatrice; Windau, Katharina; Zechmann, Maria; Jansen, Christine A; Viertlboeck, Birgit C; Göbel, Thomas W

    2013-11-01

    Natural killer cells are innate immune cells that destroy virally infected or transformed cells. They recognize these altered cells by a plethora of diverse receptors and thereby differ from other lymphocytes that use clonally distributed antigen receptors. To date, several receptor families that play a role in either activating or inhibiting NK cells have been identified in mammals. In the chicken, NK cells have been functionally and morphologically defined, however, a conclusive analysis of receptors involved in NK cell mediated functions has not been available. This is partly due to the low frequencies of NK cells in blood or spleen that has hampered their intensive characterization. Here we will review recent progress regarding the diverse NK cell receptor families, with special emphasis on novel families identified in the chicken genome with potential as chicken NK cell receptors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Novel cannabinoid receptors

    OpenAIRE

    Brown, A J

    2007-01-01

    Cannabinoids have numerous physiological effects. In the years since the molecular identification of the G protein-coupled receptors CB1 and CB2, the ion channel TRPV1, and their corresponding endogenous ligand systems, many cannabinoid-evoked actions have been shown conclusively to be mediated by one of these specific receptor targets. However, there remain several examples where these classical cannabinoid receptors do not explain observed pharmacology. Studies using mice genetically delete...

  11. Therapeutic androgen receptor ligands

    OpenAIRE

    Allan, George F.; Sui, Zhihua

    2003-01-01

    In the past several years, the concept of tissue-selective nuclear receptor ligands has emerged. This concept has come to fruition with estrogens, with the successful marketing of drugs such as raloxifene. The discovery of raloxifene and other selective estrogen receptor modulators (SERMs) has raised the possibility of generating selective compounds for other pathways, including androgens (that is, selective androgen receptor modulators, or SARMs).

  12. AMPA receptor ligands

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian

    2004-01-01

    Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player in the f......Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player...

  13. [The LDL receptor family].

    Science.gov (United States)

    Meilinger, Melinda

    2002-12-29

    The members of the LDL receptor family are structurally related endocytic receptors. Our view on these receptors has considerably changed in recent years. Not only have new members of the family been identified, but also several interesting observations have been published concerning the biological function of these molecules. The LDL receptor family members are able to bind and internalize a plethora of ligands; as a consequence, they play important roles in diverse physiological processes. These receptors are key players in the lipoprotein metabolism, vitamin homeostasis, Ca2+ homeostasis, cell migration, and embryonic development. Until recently, LDL receptor family members were thought to be classic endocytic receptors that provide cells with metabolites on one hand, while regulating the concentration of their ligands in the extracellular fluids on the other hand. However, recent findings indicate that in addition to their cargo transport function, LDL receptor family members can act as signal transducers, playing important roles in the development of the central nervous system or the skeleton. Better understanding of physiological and pathophysiological functions of these molecules may open new avenues for the treatment or prevention of many disorders.

  14. Glutamate receptor agonists

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Greenwood, Jeremy R; Bunch, Lennart;

    2011-01-01

    The neurotransmitter (S)-glutamate [(S)-Glu] is responsible for most of the excitatory neurotransmission in the central nervous system. The effect of (S)-Glu is mediated by both ionotropic and metabotropic receptors. Glutamate receptor agonists are generally a-amino acids with one or more...... stereogenic centers due to strict requirements in the agonist binding pocket of the activated state of the receptor. By contrast, there are many examples of achiral competitive antagonists. The present review addresses how stereochemistry affects the activity of glutamate receptor ligands. The review focuses...... mainly on agonists and discusses stereochemical and conformational considerations as well as biostructural knowledge of the agonist binding pockets, which is useful in the design of glutamate receptor agonists. Examples are chosen to demonstrate how stereochemistry not only determines how the agonist...

  15. Activated type I TGFbeta receptor (Alk5) kinase confers enhancedsurvival to mammary epithelial cells and accelerates mammary tumorprogression

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka-Cook, Rebecca S.; Shin, Incheol; Yi, Jae Youn; Easterly,Evangeline; Barcellos-Hoff, Mary Helen; Yingling, Jonathan M.; Zent, Roy; Arteaga, Carlos L.

    2005-01-02

    The transforming growth factor-betas (TGF{beta}s) are members of a large superfamily of pleiotropic cytokines that also includes the activins and the bone morphogenetic proteins (BMPs). Members of the TGF{beta} family regulate complex physiological processes such cell proliferation, differentiation, adhesion, cell-cell and cell-matrix interactions, motility, and cell death, among others (Massague, 1998). Dysregulation of TGF{beta} signaling contributes to several pathological processes including cancer, fibrosis, and auto-immune disorders (Massague et al., 2000). The TGF{beta}s elicit their biological effects by binding to type II and type I transmembrane receptor serine-threonine kinases (T{beta}RII and T{beta}RI) which, in turn, phosphorylated Smad 2 and Smad 3. Phosphorylated Smad 2/3 associate with Smad 4 and, as a heteromeric complex, translocate to the nucleus where they regulate gene transcription. The inhibitory Smad7 down regulates TGF{beta} signaling by binding to activated T{beta}RI and interfering with its ability to phosphorylate Smad 2/3 (Derynck and Zhang, 2003; Shi and Massague, 2003). Signaling is also regulated by Smad proteolysis. TGF{beta} receptor-mediated activation results in multi-ubiquitination of Smad 2 in the nucleus and subsequent degradation of Smad 2 by the proteasome (Lo and Massague, 1999). Activation of TGF{beta} receptors also induces mobilization of a Smad 7-Smurf complex from the nucleus to the cytoplasm; this complex recognizes the activated receptors and mediates their ubiquitination and internalization via caveolin-rich vesicles, leading to termination of TGF{beta} signaling (Di Guglielmo et al., 2003). Other signal transducers/pathways have been implicated in TGF{beta} actions. These include the extracellular signal-regulated kinase (Erk), c-Jun N-terminal kinase (Jnk), p38 mitogen-activated protein kinase (MAPK), protein phosphatase PP2A, phosphatidylinositol-3 kinase (PI3K), and the family of Rho GTPases [reviewed in

  16. Opiate receptors: an introduction.

    Science.gov (United States)

    Carmody, J J

    1987-02-01

    Current status of opiate receptors and their agonists is reviewed--basic aspects of receptor theory, the importance of stereospecificity in drug-receptor interactions and the role of 'second messengers' in drug action. The three classes of endogenous opioids, originating from three distinct genes, are discussed: pro-opiomelanocortin, giving rise to beta-endorphin, ACTH and various MSHs; pro-enkephalin, giving methionine enkephalin and leucine enkephalin; and prodynorphin; their anatomical distribution and the main classes of receptors with which they interact, the mu-receptor, with a high affinity for met-enkephalin and beta-endorphin (as well as morphine and dynorphin A); the delta-receptor for which the primary ligand is leu-enkephalin; and the kappa-receptor which is the main target for the dynorphins. Functional roles for endogenous opioids are considered. Essentially they are inhibitory to target neurones, depressing motor reflexes, baroreflexes and nociception. They also have roles in the response to physical and psychological stress.

  17. Luteinizing hormone receptor (lhcgr) as a marker gene for characterizing estrogenic endocrine-disrupting chemicals in zebrafish ovarian follicle cells.

    Science.gov (United States)

    Liu, Ka-Cheuk; Wu, Rudolf S S; Ge, Wei

    2013-10-01

    The adverse effects of endocrine-disrupting chemicals (EDCs) have been well documented; however, the action mechanisms of many EDCs remain elusive and controversial. Furthermore, the highly diversified chemical structures and low environmental concentrations of EDCs present a major challenge to their chemical detection. Clearly, there is an urgent need for simple and reliable bioassays to detect EDCs in the environment and unravel their action mechanisms. We have recently identified luteinizing hormone receptor (lhcgr) as a robust estradiol (E2)-responsive gene in cultured zebrafish ovarian follicle cells. The expression of lhcgr exhibited a distinct biphasic response to E2 over a 24-h time-course treatment, making this a unique system for characterizing estrogenic EDCs. This study was undertaken to validate this platform by testing a wide range of EDCs, including 17α-ethinylestradiol (EE2), diethylstilbestrol (DES), bisphenol A (BPA), genistein (GEN), 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane (o,p'-DDT), vinclozolin (VIN), bis(2-ethylhexyl) phthalate (DEHP), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). Diethylstilbestrol (DES), EE2 and o,p'-DDT mimicked E2 and induced a biphasic expression of lhcgr while BPA and GEN stimulated a monophasic expression in the 24-h time-course. In contrast, BDE-47, DEHP and VIN had no effect, whereas TCDD decreased lhcgr expression. Dose-response experiment showed that E2, EE2 and DES had the highest potency, which was followed by GEN, BPA and o,p'-DDT. The effects of estrogenic EDCs were further confirmed by their potentiation of hCG-induced activin βA2 subunit (inhbab) expression. In conclusion, the present study showed that the expression of lhcgr in cultured zebrafish follicle cells and its biphasic response to estrogens provide a unique in vitro platform for screening and categorizing estrogenic substances and deciphering their action mechanisms.

  18. Serotonin receptors in hippocampus.

    Science.gov (United States)

    Berumen, Laura Cristina; Rodríguez, Angelina; Miledi, Ricardo; García-Alcocer, Guadalupe

    2012-01-01

    Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a functional network that uses several serotonin receptors to regulate their roles in this particular part of the limbic system.

  19. Serotonin Receptors in Hippocampus

    Directory of Open Access Journals (Sweden)

    Laura Cristina Berumen

    2012-01-01

    Full Text Available Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a functional network that uses several serotonin receptors to regulate their roles in this particular part of the limbic system.

  20. Dopamine receptor and hypertension.

    Science.gov (United States)

    Zeng, Chunyu; Eisner, Gilbert M; Felder, Robin A; Jose, Pedro A

    2005-01-01

    Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport and reactive oxygen and by interacting with vasopressin, renin-angiotensin, and the sympathetic nervous system. Decreased renal dopamine production and/or impaired dopamine receptor function have been reported in hypertension. Disruption of any of the dopamine receptors (D(1), D(2), D(3), D(4), and D(5)) results in hypertension. In this paper, we review the mechanisms by which hypertension develops when dopamine receptor function is perturbed.

  1. Serotonin Receptors in Hippocampus

    Science.gov (United States)

    Berumen, Laura Cristina; Rodríguez, Angelina; Miledi, Ricardo; García-Alcocer, Guadalupe

    2012-01-01

    Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a functional network that uses several serotonin receptors to regulate their roles in this particular part of the limbic system. PMID:22629209

  2. Discovery of 7-methoxy-6-[4-(4-methyl-1,3-thiazol-2-yl)-1H-imidazol-5-yl]-1,3-benzothiazole (TASP0382088): a potent and selective transforming growth factor-β type I receptor inhibitor as a topical drug for alopecia.

    Science.gov (United States)

    Amada, Hideaki; Asanuma, Hajime; Koami, Takeshi; Okada, Atsushi; Endo, Mayumi; Ueda, Yasuji; Naruse, Takumi; Ikeda, Akiko

    2013-01-01

    7-Methoxy-6-[4-(4-methyl-1,3-thiazol-2-yl)-1H-imidazol-5-yl]-1,3-benzothiazole 11 (TASP0382088) was synthesized and evaluated as transforming growth factor-β (TGF-β) type I receptor (also known as activin receptor-like kinase 5 or ALK5) inhibitor. Compound 11, a potent and selective ALK5 inhibitor, exhibited good enzyme inhibitory activity (IC50=4.8 nM) as well as inhibitory activity against TGF-β-induced Smad2/3 phosphorylation at a cellular level (IC50=17 nM). The introduction of a methoxy group to the benzothiazole ring in 1 and the break up of the planarity between the imidazole ring and the thiazole ring improved the solubility in the lotion base of 11. Furthermore, the topical application of 3% 11 lotion significantly inhibited Smad2 phosphorylation in mouse skin at 8 h after application (71% inhibition, compared with vehicle-treated animals).

  3. Recognition receptors in biosensors

    CERN Document Server

    Zourob, Mohammed

    2010-01-01

    This book presents a significant and up-to-date review of the various recognition receptors, their immobilization, and an overview of the used surface characterization techniques. It includes more than 150 illustrations that help explain the ideas presented.

  4. Somatostatin receptor skintigrafi

    DEFF Research Database (Denmark)

    Rasmussen, Karin; Nielsen, Jørn Theil; Rehling, Michael

    2005-01-01

    Somatostatin receptor scintigraphy (SRS) is a very valuable imaging technique for visualisation of a diversity of neuroendocrine tumours. The sensitivity for localisation of carcinoid tumours is high, but somewhat lower for other neuroendocrine tumours. The methodology, multiple clinical aspects...

  5. Update on Melatonin Receptors. IUPHAR Review. : Melatonin Receptors

    OpenAIRE

    Jockers, Ralf; Delagrange, Philippe; Dubocovich, Margarita ,; Markus, Regina ,; Renault, Nicolas; Tosini, Gianluca; Cecon, Erika; Zlotos, Darius Paul

    2016-01-01

    International audience; Melatonin receptors are seven transmembrane-spanning proteins belonging to the G protein-coupled receptor super-family. In mammals, two melatonin receptor subtypes exit MT1 and MT2 encoded by the MTNR1A and MTNR1B genes, respectively. The current review provides an update on melatonin receptors by the corresponding sub-committee of the International Union of Basic and Clinical Pharmacology. We will highlight recent developments of melatonin receptor ligands, including ...

  6. Serotonin Receptors in Hippocampus

    OpenAIRE

    Laura Cristina Berumen; Angelina Rodríguez; Ricardo Miledi; Guadalupe García-Alcocer

    2012-01-01

    Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a fu...

  7. Receptors for enterovirus 71

    OpenAIRE

    Yamayoshi, Seiya; Fujii, Ken; Koike, Satoshi

    2014-01-01

    Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease (HFMD). Occasionally, EV71 infection is associated with severe neurological diseases, such as acute encephalitis, acute flaccid paralysis and cardiopulmonary failure. Several molecules act as cell surface receptors that stimulate EV71 infection, including scavenger receptor B2 (SCARB2), P-selectin glycoprotein ligand-1 (PSGL-1), sialylated glycan, heparan sulfate and annexin II (Anx2). SCARB2 plays crit...

  8. Adenosine receptor neurobiology: overview.

    Science.gov (United States)

    Chen, Jiang-Fan; Lee, Chien-fei; Chern, Yijuang

    2014-01-01

    Adenosine is a naturally occurring nucleoside that is distributed ubiquitously throughout the body as a metabolic intermediary. In the brain, adenosine functions as an important upstream neuromodulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways. By acting through four G-protein-coupled receptors, adenosine contributes critically to homeostasis and neuromodulatory control of a variety of normal and abnormal brain functions, ranging from synaptic plasticity, to cognition, to sleep, to motor activity to neuroinflammation, and cell death. This review begun with an overview of the gene and genome structure and the expression pattern of adenosine receptors (ARs). We feature several new developments over the past decade in our understanding of AR functions in the brain, with special focus on the identification and characterization of canonical and noncanonical signaling pathways of ARs. We provide an update on functional insights from complementary genetic-knockout and pharmacological studies on the AR control of various brain functions. We also highlight several novel and recent developments of AR neurobiology, including (i) recent breakthrough in high resolution of three-dimension structure of adenosine A2A receptors (A2ARs) in several functional status, (ii) receptor-receptor heterodimerization, (iii) AR function in glial cells, and (iv) the druggability of AR. We concluded the review with the contention that these new developments extend and strengthen the support for A1 and A2ARs in brain as therapeutic targets for neurologic and psychiatric diseases.

  9. Imidazoline receptors ligands

    Directory of Open Access Journals (Sweden)

    Agbaba Danica

    2012-01-01

    Full Text Available Extensive biochemical and pharmacological studies have determined three different subtypes of imidazoline receptors: I1-imidazoline receptors (I1-IR involved in central inhibition of sympathicus that produce hypotensive effect; I2-imidazoline receptors (I2-IR modulate monoamine oxidase B activity (MAO-B; I3-imidazoline receptors (I3-IR regulate insulin secretion from pancreatic β-cells. Therefore, the I1/I2/I3 imidazoline receptors are selected as new, interesting targets for drug design and discovery. Novel selective I1/I2/I3 agonists and antagonists have been recently developed. In the present review, we provide a brief update to the field of imidazoline research, highlighting some of the chemical diversity and progress made in the 2D-QSAR, 3D-QSAR and quantitative pharmacophore development studies of I1-IR and I2-IR imidazoline receptor ligands. Theoretical studies of I3-IR ligands are not yet performed because of insufficient number of synthesized I3-IR ligands.

  10. PF-03446962, a fully-human monoclonal antibody against transforming growth-factor β (TGFβ) receptor ALK1, in pre-treated patients with urothelial cancer: an open label, single-group, phase 2 trial.

    Science.gov (United States)

    Necchi, A; Giannatempo, P; Mariani, L; Farè, E; Raggi, D; Pennati, M; Zaffaroni, N; Crippa, F; Marchianò, A; Nicolai, N; Maffezzini, M; Togliardi, E; Daidone, M G; Gianni, A M; Salvioni, R; De Braud, F

    2014-06-01

    Despite a compelling preclinical rationale for the use of anti-angiogenic drugs in urothelial cancer (UC), short-living responses have been observed in clinical trials. PF-03446962 is a novel monoclonal antibody against Activin Receptor-Like Kinase-1 (ALK1), a type I subclass of the TGFβ receptor, with dose-dependent anti-angiogenic activity. An open label, single-group, phase 2 trial of PF-03446962 was conducted in salvage setting. Patients failing at least one chemotherapy regimen were eligible. Design provided PF-03446962 10 mg/Kg intravenously fortnightly until disease progression (PD) or unacceptable toxicity. Two-month progression-free survival (PFS) was the primary endpoint. The trial was registered with ClinicalTrials.gov, number NCT01620970. Fourteen patients were enrolled from October 2012 to July 2013. Median age was 64 years (interquartile range [IQR]: 58.2-69.5), 9 patients had a Bellmunt score of 1-2, median number of prior drugs was 3. One stable disease and 13 PD were recorded and the study met the futility stopping rule of interim analysis. Median PFS was 1.8 months (95 %CI, 1.4-2.0). After a median follow up of 7.4 months (IQR 4.5-10.9), 8 patients are alive. Median overall survival (OS) was 8 months (95 %CI, 2.9-not estimable). Most common toxicities were thrombocytopenia (G1-2 in 5 cases, persistent G3 in one, with 3 dose delays and 1 dose interruption), fatigue and abdominal pain (G1-2 in 4 cases each). Impairment of quality of life (ESAS score) was observed as well as an increase from baseline to +2 month median levels of vascular endothelial growth factor (VEGF) and interleukin-8. PF-03446962 had no activity as single drug in refractory UC and we do not recommend further investigation outside of the combination with agents targeting the VEGF receptor axis.

  11. Ionotropic crustacean olfactory receptors.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Corey

    Full Text Available The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs, the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs, as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling.

  12. Presynaptic P2 receptors?

    Science.gov (United States)

    Stone, T W; O'Kane, E M; Nikbakht, M R; Ross, F M

    2000-07-01

    Although the emphasis in ATP research has been on postjunctional receptors, there is also evidence for presynaptic receptors regulating transmitter release in the autonomic nervous system. Recent work has attempted to identify similar mechanisms in the central nervous system. Some of the existing results can be explained by the metabolism of nucleotides to adenosine or adenosine 5'-monophosphate (AMP). However, studies of presynaptic effects using sensitive electrophysiological tests such as paired-pulse interactions indicate that nucleotides can act at presynaptic sites, but that their effects may be mediated by a release of adenosine. Results are also described which indicate that, under some conditions, nucleotides can mediate phenomena such as long-term potentiation, which probably involves a significant presynaptic element. In part these effects may involve a nucleotide-induced release of adenosine and the simultaneous activation of P1 and P2 receptors.

  13. Human presynaptic receptors.

    Science.gov (United States)

    Schlicker, Eberhard; Feuerstein, Thomas

    2017-04-01

    Presynaptic receptors are sites at which transmitters, locally formed mediators or hormones inhibit or facilitate the release of a given transmitter from its axon terminals. The interest in the identification of presynaptic receptors has faded in recent years and it may therefore be justified to give an overview of their occurrence in the autonomic and central nervous system; this review will focus on presynaptic receptors in human tissues. Autoreceptors are presynaptic receptors at which a given transmitter restrains its further release, though in some instances may also increase its release. Inhibitory autoreceptors represent a typical example of a negative feedback; they are tonically activated by the respective endogenous transmitter and/or are constitutively active. Autoreceptors also play a role under pathophysiological conditions, e.g. by limiting the massive noradrenaline release occurring during congestive heart failure. They can be used for therapeutic purposes; e.g., the α2-adrenoceptor antagonist mirtazapine is used as an antidepressant and the inverse histamine H3 receptor agonist pitolisant has been marketed as a new drug for the treatment of narcolepsy in 2016. Heteroreceptors are presynaptic receptors at which transmitters from adjacent neurons, locally formed mediators (e.g. endocannabinoids) or hormones (e.g. adrenaline) can inhibit or facilitate transmitter release; they may be subject to an endogenous tone. The constipating effect of the sympathetic nervous system or of the antihypertensive drug clonidine is related to the activation of inhibitory α2-adrenoceptors on postganglionic parasympathetic neurons. Part of the stimulating effect of adrenaline on the sympathetic nervous system during stress is related to its facilitatory effect on noradrenaline release via β2-adrenoceptors.

  14. Biomimetic Receptors and Sensors

    Directory of Open Access Journals (Sweden)

    Franz L. Dickert

    2014-11-01

    Full Text Available In biomimetics, living systems are imitated to develop receptors for ions, molecules and bioparticles. The most pertinent idea is self-organization in analogy to evolution in nature, which created the key-lock principle. Today, modern science has been developing host-guest chemistry, a strategy of supramolecular chemistry for designing interactions of analytes with synthetic receptors. This can be realized, e.g., by self-assembled monolayers (SAMs or molecular imprinting. The strategies are used for solid phase extraction (SPE, but preferably in developing recognition layers of chemical sensors.

  15. Beyond the Receptor

    Institute of Scientific and Technical Information of China (English)

    Russell Jones

    2008-01-01

    @@ Had this Special Issue on plant hormones been published 5 years ago,it is likely that details about biosynthetic pathways would have taken center stage.As articles in this issue show,however,the field of plant hormone research has progressed rapidly and is now moving beyond the search for receptors.Progress in research on the mechanism of action of plant hormones has been rapid;receptors for the main classes of hormones have been identified;and the search is on for players downstream in signal-transduction chains.

  16. Assays for calcitonin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Teitelbaum, A.P.; Nissenson, R.A.; Arnaud, C.D.

    1985-01-01

    The assays for calcitonin receptors described focus on their use in the study of the well-established target organs for calcitonin, bone and kidney. The radioligand used in virtually all calcitonin binding studies is /sup 125/I-labelled salmon calcitonin. The lack of methionine residues in this peptide permits the use of chloramine-T for the iodination reaction. Binding assays are described for intact bone, skeletal plasma membranes, renal plasma membranes, and primary kidney cell cultures of rats. Studies on calcitonin metabolism in laboratory animals and regulation of calcitonin receptors are reviewed.

  17. Chemokine Receptors and Transplantation

    Institute of Scientific and Technical Information of China (English)

    Jinquan Tan; Gang Zhou

    2005-01-01

    A complex process including both the innate and acquired immune responses results in allograft rejection. Some chemokine receptors and their ligands play essential roles not only for leukocyte migration into the graft but also in facilitating dendritic and T cell trafficking between lymph nodes and the transplant in the early and late stage of the allogeneic response. This review focuses on the impact of these chemoattractant proteins on transplant outcome and novel diagnostic and therapeutic approaches for antirejection therapy based on targeting of chemokine receptors and/or their ligands. Cellular & Molecular Immunology.

  18. Angiotensin type 2 receptor (AT2R) and receptor Mas

    DEFF Research Database (Denmark)

    Villela, Daniel; Leonhardt, Julia; Patel, Neal

    2015-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striking...

  19. Characterization of melanocortin receptors.

    Science.gov (United States)

    Goetz, Aaron S; Ignar, Diane M

    2003-11-01

    This unit describes a Scintillation Proximity Assay (SPA) for the measurement of ligand binding to melanocortin receptors (MCRs) using membranes prepared from cell lines stably expressing recombinant MCRs. It provides a facile method for determining the affinity of compounds at MC1R, MC3R, MC4R, or MC5R.

  20. P2-purinerge receptorer

    DEFF Research Database (Denmark)

    Solgaard, Marie; Jørgensen, Niklas Rye

    2005-01-01

    and by osteoclasts, and agonist binding affects cell proliferation, differentiation, activity and apoptosis. With increasing knowledge of the function and role of these receptors in bone biology, they will undoubtedly be a future target for the design of new drugs which can be used for treatment of metabolic bone...

  1. Meeting report: nuclear receptors

    DEFF Research Database (Denmark)

    Tuckermann, Jan; Bourguet, William; Mandrup, Susanne

    2010-01-01

    The biannual European Molecular Biology Organization (EMBO) conference on nuclear receptors was organized by Beatrice Desvergne and Laszlo Nagy and took place in Cavtat near Dubrovnik on the Adriatic coast of Croatia September 25-29, 2009. The meeting brought together researchers from all over...

  2. Glutamate receptor ligands

    DEFF Research Database (Denmark)

    Guldbrandt, Mette; Johansen, Tommy N; Frydenvang, Karla Andrea;

    2002-01-01

    Homologation and substitution on the carbon backbone of (S)-glutamic acid [(S)-Glu, 1], as well as absolute stereochemistry, are structural parameters of key importance for the pharmacological profile of (S)-Glu receptor ligands. We describe a series of methyl-substituted 2-aminoadipic acid (AA......-ray crystallographic analyses, chemical correlation, and CD spectral analyses. The effects of the individual stereoisomers at ionotropic and metabotropic (S)-Glu receptors (iGluRs and mGluRs) were characterized. Compounds with S-configuration at the alpha-carbon generally showed mGluR2 agonist activity of similar...... limited effect on pharmacology. Structure-activity relationships at iGluRs in the rat cortical wedge preparation showed a complex pattern, some compounds being NMDA receptor agonists [e.g., EC(50) =110 microM for (2S,5RS)-5-methyl-AA (6a,b)] and some compounds showing NMDA receptor antagonist effects [e...

  3. Ginkgolides and glycine receptors

    DEFF Research Database (Denmark)

    Jaracz, Stanislav; Nakanishi, Koji; Jensen, Anders A.

    2004-01-01

    Ginkgolides from the Ginkgo biloba tree are diterpenes with a cage structure consisting of six five-membered rings and a unique tBu group. They exert a variety of biological properties. In addition to being antagonists of the platelet activating factor receptor (PAFR), it has recently been shown...

  4. Androgen receptor mutations

    NARCIS (Netherlands)

    A.O. Brinkmann (Albert); G.W. Jenster (Guido); C. Ris-Stalpers (Carolyn); J.A.G.M. van der Korput (J. A G M); H.T. Brüggenwirth (Hennie); A.L.M. Boehmer (Annemie); J. Trapman (Jan)

    1995-01-01

    textabstractMale sexual differentiation and development proceed under direct control of androgens. Androgen action is mediated by the intracellular androgen receptor, which belongs to the superfamily of ligand-dependent transcription factors. At least three pathological situations are associated wit

  5. Metformin and insulin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Vigneri, R.; Gullo, D.; Pezzino, V.

    The authors evaluated the effect of metformin (N,N-dimethylbiguanide), a biguanide known to be less toxic than phenformin, on insulin binding to its receptors, both in vitro and in vivo. Specific /sup 125/I-insulin binding to cultured IM-9 human lymphocytes and MCF-7 human breast cancer cells was determined after preincubation with metformin. Specific /sup 125/I-insulin binding to circulating monocytes was also evaluated in six controls, eight obese subjects, and six obese type II diabetic patients before and after a short-term treatment with metformin. Plasma insulin levels and blood glucose were also measured on both occasions. Metformin significantly increased insulin binding in vitro to both IM-9 lymphocytes and MCF-7 cells; the maximum increment was 47.1% and 38.0%, respectively. Metformin treatment significantly increased insulin binding in vivo to monocytes of obese subjects and diabetic patients. Scatchard analysis indicated that the increased binding was mainly due to an increase in receptor capacity. Insulin binding to monocytes of normal controls was unchanged after metformin as were insulin levels in all groups; blood glucose was significantly reduced after metformin only in diabetic patients. These data indicate that metformin increases insulin binding to its receptors in vitro and in vivo. The effect in vivo is observed in obese subjects and in obese type II diabetic patients, paralleling the clinical effectiveness of this antidiabetic agent, and is not due to receptor regulation by circulating insulin, since no variation in insulin levels was recorded.

  6. Deletion of IL-4 receptor alpha on dendritic cells renders BALB/c mice hypersusceptible to Leishmania major infection.

    Directory of Open Access Journals (Sweden)

    Ramona Hurdayal

    2013-10-01

    Full Text Available In BALB/c mice, susceptibility to infection with the intracellular parasite Leishmania major is driven largely by the development of T helper 2 (Th2 responses and the production of interleukin (IL-4 and IL-13, which share a common receptor subunit, the IL-4 receptor alpha chain (IL-4Rα. While IL-4 is the main inducer of Th2 responses, paradoxically, it has been shown that exogenously administered IL-4 can promote dendritic cell (DC IL-12 production and enhance Th1 development if given early during infection. To further investigate the relevance of biological quantities of IL-4 acting on DCs during in vivo infection, DC specific IL-4Rα deficient (CD11c(creIL-4Rα(-/lox BALB/c mice were generated by gene targeting and site-specific recombination using the cre/loxP system under control of the cd11c locus. DNA, protein, and functional characterization showed abrogated IL-4Rα expression on dendritic cells and alveolar macrophages in CD11c(creIL-4Rα(-/lox mice. Following infection with L. major, CD11c(creIL-4Rα(-/lox mice became hypersusceptible to disease, presenting earlier and increased footpad swelling, necrosis and parasite burdens, upregulated Th2 cytokine responses and increased type 2 antibody production as well as impaired classical activation of macrophages. Hypersusceptibility in CD11c(creIL-4Rα(-/lox mice was accompanied by a striking increase in parasite burdens in peripheral organs such as the spleen, liver, and even the brain. DCs showed increased parasite loads in CD11c(creIL-4Rα(-/lox mice and reduced iNOS production. IL-4Rα-deficient DCs produced reduced IL-12 but increased IL-10 due to impaired DC instruction, with increased mRNA expression of IL-23p19 and activin A, cytokines previously implicated in promoting Th2 responses. Together, these data demonstrate that abrogation of IL-4Rα signaling on DCs is severely detrimental to the host, leading to rapid disease progression, and increased survival of parasites in infected

  7. Levamisole receptors: a second awakening

    Science.gov (United States)

    Martin, Richard J.; Robertson, Alan P.; Buxton, Samuel K.; Beech, Robin N.; Charvet, Claude L.; Neveu, Cedric

    2012-01-01

    Levamisole and pyrantel are old (1965) but useful anthelmintics that selectively activate nematode acetylcholine ion-channel receptors; they are used to treat roundworm infections in humans and animals. Interest in their actions has surged, giving rise to new knowledge and technical advances, including an ability to reconstitute receptors that reveal more details of modes of action/resistance. We now know that the receptors are plastic and may form diverse species-dependent subtypes of receptor with different sensitivities to individual cholinergic anthelmintics. Understanding the biology of the levamisole receptors is expected to inform other studies on anthelmintics (ivermectin and emodepside) that act on ion-channels. PMID:22607692

  8. Histamine H3-receptor isoforms.

    Science.gov (United States)

    Bakker, R A

    2004-10-01

    Increasing evidence supports a role for HA as a neurotransmitter and neuromodulator in various brain functions, including emotion, cognition, and feeding. The recent cloning of the histamine H3 receptor allowed for the subsequent cloning of a variety of H3 receptor isoforms from different species as well as the H4 receptor. As a result a wide variety of H3-receptor isoforms are now known that display differential brain expression patterns and signalling properties. These recent discoveries are discussed in view of the growing interest of the H3 receptor as a target for the development of potential therapeutics.

  9. Virally encoded 7TM receptors

    DEFF Research Database (Denmark)

    Rosenkilde, M M; Waldhoer, M; Lüttichau, H R

    2001-01-01

    A number of herpes- and poxviruses encode 7TM G-protein coupled receptors most of which clearly are derived from their host chemokine system as well as induce high expression of certain 7TM receptors in the infected cells. The receptors appear to be exploited by the virus for either immune evasion...... in various parts of the viral life cyclus. Most of the receptors encoded by human pathogenic virus are still orphan receptors, i.e. the endogenous ligand is unknown. In the few cases where it has been possible to characterize these receptors pharmacologically, they have been found to bind a broad spectrum...... expression of this single gene in certain lymphocyte cell lineages leads to the development of lesions which are remarkably similar to Kaposi's sarcoma, a human herpesvirus 8 associated disease. Thus, this and other virally encoded 7TM receptors appear to be attractive future drug targets....

  10. Receptor tyrosine kinases in carcinogenesis.

    Science.gov (United States)

    Zhang, Xiao-Ying; Zhang, Pei-Ying

    2016-11-01

    Receptor tyrosine kinases (RTKs) are cell surface glycoproteins with enzymatic activity involved in the regulation of various important functions. In all-important physiological functions including differentiation, cell-cell interactions, survival, proliferation, metabolism, migration and signaling these receptors are the key players of regulation. Additionally, mutations of RTKs or their overexpression have been described in many human cancers and are being explored as a novel avenue for a new therapeutic approach. Some of the deregulated RTKs observed to be significantly affected in cancers included vascular endothelial growth factor receptor, epidermal growth factor receptor, fibroblast growth factor receptor, RTK-like orphan receptor 1 (ROR1) and the platelet-derived growth factor receptor. These deregulated RTKs offer attractive possibilities for the new anticancer therapeutic approach involving specific targeting by monoclonal antibodies as well as kinase. The present review aimed to highlight recent perspectives of RTK ROR1 in cancer.

  11. TSH RECEPTOR AUTOANTIBODIES

    Science.gov (United States)

    Michalek, Krzysztof; Morshed, Syed A.; Latif, Rauf; Davies, Terry F.

    2009-01-01

    Thyrotropin receptor autoantibodies (TSHR-Abs) of the stimulating variety are the hallmark of Graves’ disease. The presence of immune defects leading to synthesis of TSHR-Abs causes hyperthyroidism and is associated with other extrathyroidal manifestations. Further characterization of these antibodies has now been made possible by the generation of monoclonal antibodies with this unique stimulating capacity as well as similar TSHR-Abs not associated with hyperthyroidism. Their present classification divides TSHR-Abs into stimulating, blocking (competing with TSH binding) and neutral (no signaling). Recent studies using monoclonal TSHR-Abs has revealed that stimulating and blocking antibodies bind to the receptor using mostly conformational epitopes, whilst neutral antibodies utilize exclusively linear peptides. Subtle differences in epitopes for stimulating and blocking antibodies account for the diversity of their biological actions. Recently non-classical signaling elicited by neutral antibodies has also been described, raising the need for a new classification of TSHR-Abs. PMID:19332151

  12. Ligand-Receptor Interactions

    CERN Document Server

    Bongrand, Pierre

    2008-01-01

    The formation and dissociation of specific noncovalent interactions between a variety of macromolecules play a crucial role in the function of biological systems. During the last few years, three main lines of research led to a dramatic improvement of our understanding of these important phenomena. First, combination of genetic engineering and X ray cristallography made available a simultaneous knowledg of the precise structure and affinity of series or related ligand-receptor systems differing by a few well-defined atoms. Second, improvement of computer power and simulation techniques allowed extended exploration of the interaction of realistic macromolecules. Third, simultaneous development of a variety of techniques based on atomic force microscopy, hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or flexible transducers yielded direct experimental information of the behavior of single ligand receptor bonds. At the same time, investigation of well defined cellular models raised the ...

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

    Science.gov (United States)

    Keegan, A D; Pierce, J H

    1994-02-01

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

  14. [Lipoprotein receptors. Old acquaintances and newcomers].

    Science.gov (United States)

    Ducobu, J

    1997-02-01

    Lipoprotein receptors are plasma membrane proteins of high affinity which interact with circulating lipoprotein particles. The well characterized LDL receptor continues to be analysed and some new findings on its intracellular mechanisms of action have emerged. New lipoprotein receptors have recently been described: the chylomicron remnant receptor or LDL-related protein (LRP), the lipolysis stimulated receptor (LSR), the very low density lipoprotein receptor (VLDLR), the HDL receptor (HDLR) and the scavenger receptor (SR). The molecular details of the receptors will facilitate the development of new therapeutic means to improve receptor-mediated clearance of lipoproteins.

  15. Similarity of Bovine Rotavirus Receptor and Human Rotavirus Receptor

    Institute of Scientific and Technical Information of China (English)

    苏琦华; 訾自强; 潘菊芬; 徐燕

    2004-01-01

    The monoclonal antibody against bovine rotavirus (BRV) receptor (BRV-R-mAb) was used to explore the similarity between the receptors of BRV and human rotavirus (HRV). ELISA, dot immunobinding assay, cell protection assay, solid-phase assay and immunohistochemistry method were applied. BRV-R-mAb bound both anti-BRV IgG and anti-HRV IgG respectively and could protect MA 104 cells against BRV and HRV challenges. Immunohistochemistry test showed that there were rotavirus receptors on the surfaces of foetal intestinal, tracheal mucosa and MA 104 cells membrane. We purified the rotavirus receptors on MA 104 ceils, which could bind both BRV and HRV in vitro. It is concluded that BRV receptor and HRV receptor are homogenous proteins and can be recognized by both BRV and HRV.

  16. Melatonin Receptor Genes in Vertebrates

    Directory of Open Access Journals (Sweden)

    Hua Dong Yin

    2013-05-01

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

  17. Flavivirus Entry Receptors: An Update

    Directory of Open Access Journals (Sweden)

    Manuel Perera-Lecoin

    2013-12-01

    Full Text Available Flaviviruses enter host cells by endocytosis initiated when the virus particles interact with cell surface receptors. The current model suggests that flaviviruses use at least two different sets of molecules for infectious entry: attachment factors that concentrate and/or recruit viruses on the cell surface and primary receptor(s that bind to virions and direct them to the endocytic pathway. Here, we present the currently available knowledge regarding the flavivirus receptors described so far with specific attention to C-type lectin receptors and the phosphatidylserine receptors, T-cell immunoglobulin and mucin domain (TIM and TYRO3, AXL and MER (TAM. Their role in flavivirus attachment and entry as well as their implication in the virus biology will be discussed in depth.

  18. Angiotensin II receptors in testes

    Energy Technology Data Exchange (ETDEWEB)

    Millan, M.A.; Aguilera, G.

    1988-05-01

    Receptors for angiotensin II (AII) were identified and characterized in testes of rats and several primate species. Autoradiographic analysis of the binding of 125I-labeled (Sar1,Ile8)AII to rat, rhesus monkey, cebus monkey, and human testicular slide-mounted frozen sections indicated specific binding to Leydig cells in the interstitium. In rat collagenase-dispersed interstitial cells fractionated by Percoll gradient, AII receptor content was parallel to that of hCG receptors, confirming that the AII receptors are in the Leydig cells. In rat dispersed Leydig cells, binding was specific for AII and its analogs and of high affinity (Kd, 4.8 nM), with a receptor concentration of 15 fmol/10(6) cells. Studies of AII receptors in rat testes during development reveals the presence of high receptor density in newborn rats which decreases toward the adult age (4934 +/- 309, 1460 +/- 228, 772 +/- 169, and 82 +/- 12 fmol/mg protein at 5, 15, 20, and 30 days of age, respectively) with no change in affinity. At all ages receptors were located in the interstitium, and the decrease in binding was parallel to the decrease in the interstitial to tubular ratio observed with age. AII receptor properties in membrane-rich fractions from prepuberal testes were similar in the rat and rhesus monkey. Binding was time and temperature dependent, reaching a plateau at 60 min at 37 C, and was increased by divalent cations, EGTA, and dithiothreitol up to 0.5 mM. In membranes from prepuberal monkey testes, AII receptors were specific for AII analogs and of high affinity (Kd, 4.2 nM) with a receptor concentration of 7599 +/- 1342 fmol/mg protein. The presence of AII receptors in Leydig cells in rat and primate testes in conjunction with reports of the presence of other components of the renin-angiotensin system in the testes suggests that the peptide has a physiological role in testicular function.

  19. Uncompetitive antagonism of AMPA receptors

    DEFF Research Database (Denmark)

    Andersen, Trine F; Tikhonov, Denis B; Bølcho, Ulrik;

    2006-01-01

    Philanthotoxins are uncompetitive antagonists of Ca2+-permeable AMPA receptors presumed to bind to the pore-forming region, but a detailed molecular mechanism for this interaction is missing. Here a small library of novel philanthotoxins was designed and synthesized using a solid-phase strategy. ...... polyamine toxins antagonize the AMPA receptor ion channel and provide the basis for rational development of uncompetitive antagonists of AMPA receptors....

  20. 老年慢性阻塞性肺疾病患者的血清激活素A和转化生长因子β1与肺功能变化的相关性%Clinic significance and correlations of serum activin A,transforming growth factor beta 1 and pulmonary function of elderly patients with chronic obstructive pulmonary disease

    Institute of Scientific and Technical Information of China (English)

    樊晓曦

    2016-01-01

    Objective To explore the clinic significance and correlations of serum activin A,transforming growth factor β1 and pulmonary function of elderly patients with chronic obstructive pulmonary disease. Methods 95 patients with elderly COPD were collected as the research object from September 2014 to September 2015. Sixty healthy subjects served as controls. The concentrations of ACTA and TGF - β1 were deter-mined using ELISA. The pearson correlation test was performed to analyze the correlation between ACTA,TGF - β1 and pulmonary function in-dex. Results Compared with those in healthy controls,plasma ACTA and TGF - β1 levels in elderly COPD increased significantly( P < 0. 05). The higher of the COPD level,the higher the level of ACTA and TGF - beta 1( P < 0. 05). The higher the level of pulmonary function damage, the higher the level of ACTA and TGF - beta 1. Pearson correlation analysis showed that the serum levels of ACTA,TGF - β1 were negatively cor-related with FEV1%( r = - 0. 687,- 0. 751,P < 0. 05),and they were also negatively correlated with FEV1 / FVC( r = - 0. 613,- 0. 598, P < 0. 05). Conclusion ACTA and TGF - β1 play important roles in the progression of COPD,and have correlation with pulmonary function changes.%目的:探讨老年慢性阻塞性肺疾病(COPD)患者的血清激活素 A(ACTA)和转化生长因子β1(TGF -β1)与肺功能变化的相关性。方法选择于2014年9月至2015年9月收治的老年 COPD 患者95例作为研究对象,选取同期60例健康体检者作为对照组。采用酶联免疫吸附法(ELISA)法检测血清 ACTA 和 TGF -β1水平。采用 Pearson 相关性分析法分析 ACTA 和 TGF -β1水平与各肺功能指标的相关性。结果与健康对照组相比,老年 COPD 患者的 ACTA和 TGF -β1水平显著升高( P <0.05)。COPD 严重程度越高,ACTA 和 TGF -β1水平越高( P <0.05)。肺功能损伤等级越高,ACTA 和 TGF -β1水平随之显著增高( P <0.05

  1. GABAρ1/GABAAα1 receptor chimeras to study receptor desensitization

    Science.gov (United States)

    Martínez-Torres, Ataúlfo; Demuro, Angelo; Miledi, Ricardo

    2000-01-01

    γ-Aminobutyrate type C (GABAC) receptors are ligand-gated ion channels that are expressed preponderantly in the vertebrate retina and are characterized, among other things, by a very low rate of desensitization and resistance to the specific GABAA antagonist bicuculline. To examine which structural elements determine the nondesensitizing character of the human homomeric ρ1 receptor, we used a combination of gene chimeras and electrophysiology of receptors expressed in Xenopus oocytes. Two chimeric genes were constructed, made up of portions of the ρ1-subunit and of the α1-subunit of the GABAA receptor. When expressed in Xenopus oocytes, one chimeric gene (ρ1/α1) formed functional homooligomeric receptors that were fully resistant to bicuculline and were blocked by the specific GABAC antagonist (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid and by zinc. Moreover, these chimeric receptors had a fast-desensitizing component, even faster than that of heterooligomeric GABAA receptors, in striking contrast to the almost nil desensitization of wild-type ρ1 (wt ρ1) receptors. To see whether the fast-desensitizing characteristic of the chimera was determined by the amino acids forming the ion channels, we replaced the second transmembrane segment (TM2) of ρ1 by that of the α1-subunit of GABAA. Although the α1-subunit forms fast-desensitizing receptors when coexpressed with other GABAA subunits, the sole transfer of the α1TM2 segment to ρ1 was not sufficient to form desensitizing receptors. All this suggests that the slow-desensitizing trait of ρ1 receptors is determined by a combination of several interacting domains along the molecule. PMID:10725369

  2. Renal dopamine receptors and hypertension.

    Science.gov (United States)

    Hussain, Tahir; Lokhandwala, Mustafa F

    2003-02-01

    Dopamine has been recognized as an important modulator of central as well as peripheral physiologic functions in both humans and animals. Dopamine receptors have been identified in a number of organs and tissues, which include several regions within the central nervous system, sympathetic ganglia and postganglionic nerve terminals, various vascular beds, the heart, the gastrointestinal tract, and the kidney. The peripheral dopamine receptors influence cardiovascular and renal function by decreasing afterload and vascular resistance and promoting sodium excretion. Within the kidney, dopamine receptors are present along the nephron, with highest density on proximal tubule epithelial cells. It has been reported that there is a defective dopamine receptor, especially D(1) receptor function, in the proximal tubule of various animal models of hypertension as well as in humans with essential hypertension. Recent reports have revealed the site of and the molecular mechanisms responsible for the defect in D(1) receptors in hypertension. Moreover, recent studies have also demonstrated that the disruption of various dopamine receptor subtypes and their function produces hypertension in rodents. In this review, we present evidence that dopamine and dopamine receptors play an important role in regulating renal sodium excretion and that defective renal dopamine production and/or dopamine receptor function may contribute to the development of various forms of hypertension.

  3. 活化素A和视黄酸诱导骨髓间充质干细胞体外分化为胰岛素分泌细胞%In vitro differentiation of bone marrow mesenchymal stem cells induced by activin A and all-trans retinoic acid into insulin-producing cells

    Institute of Scientific and Technical Information of China (English)

    王启伟; 于瑾; 刘兴茂; 李世崇; 叶玲玲; 刘红; 吴本传; 陈昭烈

    2006-01-01

    human being in the 21st century. Islet transplantation is considered to be the most effective approach to cure type Ⅰ diabetes mellitus. However, lack of donor tissue limits the application of this therapy. However, recent progress of stem cell research shows that stem cell therapy may be a potential means to solve this problem.OBJECTIVE: To take activin A and all-trans retinoic acid (AR) in inducing the differentiation of bone marrow mesenchymal stem cells (MSCs) and explore its possibility DESIGN: A randomized controlled experiment.SETTING: Institute of Biotechnology, Academy of Military Medical SciencesMATERIALS: This experiment was conducted at the Institute of Biotechnology, Academy of Military Medical Sciences from November 2004to June 2005. Six male Sprague-Dawley rats, with body mass of 150-160g, were provided by the Experimental Animal Center of Academy of Military Medical Sciences.METHODS: Femoral bone marrow of the rats was extracted under aseptic condition. Bone marrow mesenchymal stem cells (MSCs) were isolated with density gradient centrifugation. Passaged MSCs were randomly divided into 4 groups: high concentration of glucose (HG), AR, beta-mercaptoethanol (ME) and negative control groups. MSCs were induced to differentiate into IPCs with conditional medium containing high concentration glucose, activin A, RA and ME etc. After induction, phenotypes of differentiated cells were examined by immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR).MAIN OUTCOME MEASURES: Expression of insulin and glucagon of differentiated cells were examined by immunocytochemistry. Insulin-1 mR-NA expression of differentiated cells was detected by RT-PCR.RESULTS: After bone marrow mesenchymal stem cells were induced,there were scattered insulin-and glucagon-positive cells in the HG group,many insulin-and glucagon-positive cells in the AR and ME groups, and these cells formed insulin-like structure. The expression of insulin-1mRNA could be observed

  4. Role of Activin A in Immune Response to Breast Cancer

    Science.gov (United States)

    2015-12-01

    2014;124:2246–59. 41. Postow MA, Callahan MK, Wolchok JD. The antitumor immunity of ipilimumab: (T-cell) memories to last a lifetime? Clin Cancer Res 2012;18...Lagorce-Pages C, et al. Type, density, and location of immune cells within human colorectal tumors predict clinical outcome. Science 2006;313:1960–4...4] Pagès F, Galon J, Dieu-Nosjean MC, Tartour E, Sautès-Fridman C, Fridman WH. Immune infiltration in human tumors: a prognostic factor that should

  5. Role of Activin A in Immune Response to Breast Cancer

    Science.gov (United States)

    2014-12-01

    arabinomannan and mannin, has immunomodulatory properties (123). This was tested in a Japanese phase III, randomized trial in patients with stage IIB – IVA ...tolerability IMRT 5 days a week for 7 weeks with cetuximab and ipi at week 4 for 3, 21 day courses NCI NCT01711515 Cervical cancer (stage IB– IVA ) One arm: ipi...endothelial cells in inflammation. Nat Rev Immunol (2007) 7:803–15. doi:10.1038/nri2171 41. Ley K, Laudanna C, Cybulsky MI, Nourshargh S. Getting to

  6. Role of Activin A in Immune Response to Breast Cancer

    Science.gov (United States)

    2016-12-01

    in enhanced actA release, consistent with a compensatory mechanism described in development (Carvalho et al., J Cell Sci , 2007). Here we tested the...anti-PD-1-resistant preclinical tumor model with which to identify mechanisms of resis- tance, which should provide novel insights to expand the...enhanced actA release, consistent with a compensatory mech- anism described by Carvalho et al., J Cell Sci , 2007. Here we tested the hypothesis that both

  7. Leptin and its receptors.

    Science.gov (United States)

    Wada, Nobuhiro; Hirako, Satoshi; Takenoya, Fumiko; Kageyama, Haruaki; Okabe, Mai; Shioda, Seiji

    2014-11-01

    Leptin is mainly produced in the white adipose tissue before being secreted into the blood and transported across the blood-brain barrier. Leptin binds to a specific receptor (LepR) that has numerous subtypes (LepRa, LepRb, LepRc, LepRd, LepRe, and LepRf). LepRb, in particular, is expressed in several brain nuclei, including the arcuate nucleus, the paraventricular nucleus, and the dorsomedial, lateral and ventromedial regions of the hypothalamus. LepRb is also co-expressed with several neuropeptides, including proopiomelanocortin, neuropeptide Y, galanin, galanin-like peptide, gonadotropin-releasing hormone, tyrosine hydroxylase and neuropeptide W. Functionally, LepRb induces activation of the JAK2/ERK, /STAT3, /STAT5 and IRS/PI3 kinase signaling cascades, which are important for the regulation of energy homeostasis and appetite in mammals. In this review, we discuss the structure, genetics and distribution of the leptin receptors, and their role in cell signaling mechanisms.

  8. Axonal GABAA receptors.

    Science.gov (United States)

    Trigo, Federico F; Marty, Alain; Stell, Brandon M

    2008-09-01

    Type A GABA receptors (GABA(A)Rs) are well established as the main inhibitory receptors in the mature mammalian forebrain. In recent years, evidence has accumulated showing that GABA(A)Rs are prevalent not only in the somatodendritic compartment of CNS neurons, but also in their axonal compartment. Evidence for axonal GABA(A)Rs includes new immunohistochemical and immunogold data: direct recording from single axonal terminals; and effects of local applications of GABA(A)R modulators on action potential generation, on axonal calcium signalling, and on neurotransmitter release. Strikingly, whereas presynaptic GABA(A)Rs have long been considered inhibitory, the new studies in the mammalian brain mostly indicate an excitatory action. Depending on the neuron that is under study, axonal GABA(A)Rs can be activated by ambient GABA, by GABA spillover, or by an autocrine action, to increase either action potential firing and/or transmitter release. In certain neurons, the excitatory effects of axonal GABA(A)Rs persist into adulthood. Altogether, axonal GABA(A)Rs appear as potent neuronal modulators of the mammalian CNS.

  9. Discoidin Domain Receptor 1

    Science.gov (United States)

    Song, Sunmi; Shackel, Nicholas A.; Wang, Xin M.; Ajami, Katerina; McCaughan, Geoffrey W.; Gorrell, Mark D.

    2011-01-01

    Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that binds and is activated by collagens. Transcriptional profiling of cirrhosis in human liver using a DNA array and quantitative PCR detected elevated mRNA expression of DDR1 compared with that in nondiseased liver. The present study characterized DDR1 expression in cirrhotic and nondiseased human liver and examined the cellular effects of DDR1 expression. mRNA expression of all five isoforms of DDR1 was detected in human liver, whereas DDR1a demonstrated differential expression in liver with hepatitis C virus and primary biliary cirrhosis compared with nondiseased liver. In addition, immunoblot analysis detected shed fragments of DDR1 more readily in cirrhotic liver than in nondiseased liver. Inasmuch as DDR1 is subject to protease-mediated cleavage after prolonged interaction with collagen, this differential expression may indicate more intense activation of DDR1 protein in cirrhotic compared with nondiseased liver. In situ hybridization and immunofluorescence localized intense DDR1 mRNA and protein expression to epithelial cells including hepatocytes at the portal-parenchymal interface and the luminal aspect of the biliary epithelium. Overexpression of DDR1a altered hepatocyte behavior including increased adhesion and less migration on extracelular matrix substrates. DDR1a regulated extracellular expression of matrix metalloproteinases 1 and 2. These data elucidate DDR1 function pertinent to cirrhosis and indicate the importance of epithelial cell–collagen interactions in chronic liver injury. PMID:21356365

  10. Trace amine-associated receptors are olfactory receptors in vertebrates.

    Science.gov (United States)

    Liberles, Stephen D

    2009-07-01

    The mammalian nose is a powerful chemosensor, capable of detecting and distinguishing a myriad of chemicals. Sensory neurons in the olfactory epithelium contain two types of chemosensory G protein-coupled receptors (GPCRs): odorant receptors (ORs), which are encoded by the largest gene family in mammals, and trace amine-associated receptors (TAARs), a smaller family of receptors distantly related to biogenic amine receptors. Do TAARs play a specialized role in olfaction distinct from that of ORs? Genes encoding TAARs are found in diverse vertebrates, from fish to mice to humans. Like OR genes, each Taar gene defines a unique population of canonical sensory neurons dispersed in a single zone of the olfactory epithelium. Ligands for mouse TAARs include a number of volatile amines, several of which are natural constituents of mouse urine, a rich source of rodent social cues. One chemical, 2-phenylethylamine, is reported to be enriched in the urine of stressed animals, and two others, trimethylamine and isoamylamine, are enriched in male versus female urine. Furthermore, isoamylamine has been proposed to be a pheromone that induces puberty acceleration in young female mice. These data raise the possibility that some TAARs are pheromone receptors in the nose, a hypothesis consistent with recent data suggesting that the olfactory epithelium contains dedicated pheromone receptors, separate from pheromone receptors in the vomeronasal organ. Future experiments will clarify the roles of TAARs in olfaction.

  11. GABAB receptors modulate NMDA receptor calcium signals in dendritic spines.

    Science.gov (United States)

    Chalifoux, Jason R; Carter, Adam G

    2010-04-15

    Metabotropic GABA(B) receptors play a fundamental role in modulating the excitability of neurons and circuits throughout the brain. These receptors influence synaptic transmission by inhibiting presynaptic release or activating postsynaptic potassium channels. However, their ability to directly influence different types of postsynaptic glutamate receptors remains unresolved. Here we examine GABA(B) receptor modulation in layer 2/3 pyramidal neurons from the mouse prefrontal cortex. We use two-photon laser-scanning microscopy to study synaptic modulation at individual dendritic spines. Using two-photon optical quantal analysis, we first demonstrate robust presynaptic modulation of multivesicular release at single synapses. Using two-photon glutamate uncaging, we then reveal that GABA(B) receptors strongly inhibit NMDA receptor calcium signals. This postsynaptic modulation occurs via the PKA pathway and does not affect synaptic currents mediated by AMPA or NMDA receptors. This form of GABA(B) receptor modulation has widespread implications for the control of calcium-dependent neuronal function.

  12. Possible Relevance of Receptor-Receptor Interactions between Viral- and Host-Coded Receptors for Viral-Induced Disease

    Directory of Open Access Journals (Sweden)

    Luigi F. Agnati

    2007-01-01

    Full Text Available It has been demonstrated that some viruses, such as the cytomegalovirus, code for G-protein coupled receptors not only to elude the immune system, but also to redirect cellular signaling in the receptor networks of the host cells. In view of the existence of receptor-receptor interactions, the hypothesis is introduced that these viral-coded receptors not only operate as constitutively active monomers, but also can affect other receptor function by interacting with receptors of the host cell. Furthermore, it is suggested that viruses could also insert not single receptors (monomers, but clusters of receptors (receptor mosaics, altering the cell metabolism in a profound way. The prevention of viral receptor-induced changes in host receptor networks may give rise to novel antiviral drugs that counteract viral-induced disease.

  13. Sensory receptors in monotremes.

    Science.gov (United States)

    Proske, U; Gregory, J E; Iggo, A

    1998-01-01

    This is a summary of the current knowledge of sensory receptors in skin of the bill of the platypus, Ornithorhynchus anatinus, and the snout of the echidna, Tachyglossus aculeatus. Brief mention is also made of the third living member of the monotremes, the long-nosed echidna, Zaglossus bruijnii. The monotremes are the only group of mammals known to have evolved electroreception. The structures in the skin responsible for the electric sense have been identified as sensory mucous glands with an expanded epidermal portion that is innervated by large-diameter nerve fibres. Afferent recordings have shown that in both platypuses and echidnas the receptors excited by cathodal (negative) pulses and inhibited by anodal (positive) pulses. Estimates give a total of 40,000 mucous sensory glands in the upper and lower bill of the platypus, whereas there are only about 100 in the tip of the echidna snout. Recording of electroreceptor-evoked activity from the brain of the platypus have shown that the largest area dedicated to somatosensory input from the bill, S1, shows alternating rows of mechanosensory and bimodal neurons. The bimodal neurons respond to both electrosensory and mechanical inputs. In skin of the platypus bill and echidna snout, apart from the electroreceptors, there are structures called push rods, which consist of a column of compacted cells that is able to move relatively independently of adjacent regions of skin. At the base of the column are Merkel cell complexes, known to be type I slowly adapting mechanoreceptors, and lamellated corpuscles, probably vibration receptors. It has been speculated that the platypus uses its electric sense to detect the electromyographic activity from moving prey in the water and for obstacle avoidance. Mechanoreceptors signal contact with the prey. For the echidna, a role for the electrosensory system has not yet been established during normal foraging behaviour, although it has been shown that it is able to detect the presence

  14. Coronavirus spike-receptor interactions

    NARCIS (Netherlands)

    Mou, H.

    2015-01-01

    Coronaviruses cause important diseases in humans and animals. Coronavirus infection starts with the virus binding with its spike proteins to molecules present on the surface of host cells that act as receptors. This spike-receptor interaction is highly specific and determines the virus’ cell, tissue

  15. Hydrocarbon Receptor Pathway in Dogs

    NARCIS (Netherlands)

    Steenbeek, F.G. van; Spee, B.; Penning, L.C.; Kummeling, A.; Gils, I.H.M.; Grinwis, G.C.M.; Leenen, D. van; Holstege, F.C.P.; Vos-Loohuis, M.; Rothuizen, J.; Leegwater, P.A.J.

    2013-01-01

    The aryl hydrocarbon receptor (AHR) mediates biological responses to toxic chemicals. An unexpected role for AHR in vascularization was suggested when mice lacking AHR displayed impaired closure of the ductus venosus after birth, as did knockout mice for aryl hydrocarbon receptor interacting protein

  16. Hydrocarbon Receptor Pathway in Dogs

    NARCIS (Netherlands)

    Steenbeek, F.G. van; Spee, B.; Penning, L.C.; Kummeling, A.; Gils, I.H.M.; Grinwis, G.C.M.; Leenen, D. van; Holstege, F.C.P.; Vos-Loohuis, M.; Rothuizen, J.; Leegwater, P.A.J.

    The aryl hydrocarbon receptor (AHR) mediates biological responses to toxic chemicals. An unexpected role for AHR in vascularization was suggested when mice lacking AHR displayed impaired closure of the ductus venosus after birth, as did knockout mice for aryl hydrocarbon receptor interacting

  17. Purinergic Receptors in Thrombosis and Inflammation

    National Research Council Canada - National Science Library

    Hechler, Béatrice; Gachet, Christian

    2015-01-01

    .... Beyond platelets, these 3 receptors, along with the P2Y2, P2Y6, and P2X7 receptors, constitute the main P2 receptors mediating the proinflammatory effects of nucleotides, which play important roles...

  18. Dopamine Receptors and Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Shin Hisahara

    2011-01-01

    Full Text Available Parkinson's disease (PD is a progressive extrapyramidal motor disorder. Pathologically, this disease is characterized by the selective dopaminergic (DAergic neuronal degeneration in the substantia nigra. Correcting the DA deficiency in PD with levodopa (L-dopa significantly attenuates the motor symptoms; however, its effectiveness often declines, and L-dopa-related adverse effects emerge after long-term treatment. Nowadays, DA receptor agonists are useful medication even regarded as first choice to delay the starting of L-dopa therapy. In advanced stage of PD, they are also used as adjunct therapy together with L-dopa. DA receptor agonists act by stimulation of presynaptic and postsynaptic DA receptors. Despite the usefulness, they could be causative drugs for valvulopathy and nonmotor complication such as DA dysregulation syndrome (DDS. In this paper, physiological characteristics of DA receptor familyare discussed. We also discuss the validity, benefits, and specific adverse effects of pharmaceutical DA receptor agonist.

  19. Opioids and their peripheral receptors

    Directory of Open Access Journals (Sweden)

    Francesco Amato

    2012-12-01

    Full Text Available The inflammation of peripheral tissues leads the primary afferent neurons, in particular at the cell bodies level located in the DRG (dorsal root ganglia, to an increased synthesis of opioid receptors: determining an “up-regulation”. After that opioid receptors are transported at the level of the nociceptive terminals, they are incorporated into the neuronal membrane becoming functional receptors. The above receptor proteins bind to opioid produced by immune cells or the exogenous ones. This leads to a direct or indirect suppression of the Ca2+ currents induced by TRPV1 or the currents of the Na+, resulting in neuronal reduced excitability and in transmitted signals decrease. The observation that the immune system is able to modulate the pain by ligands that interact with the opioid receptors located on sensory neurons, may have broad implications for the development of innovative and safer pain drugs.

  20. Ryanodine receptor channelopathies

    Science.gov (United States)

    Betzenhauser, Matthew J.

    2010-01-01

    Ryanodine receptors (RyR) are intracellular Ca2+-permeable channels that provide the sarcoplasmic reticulum Ca2+ release required for skeletal and cardiac muscle contractions. RyR1 underlies skeletal muscle contraction, and RyR2 fulfills this role in cardiac muscle. Over the past 20 years, numerous mutations in both RyR isoforms have been identified and linked to skeletal and cardiac diseases. Malignant hyperthermia, central core disease, and catecholaminergic polymorphic ventricular tachycardia have been genetically linked to mutations in either RyR1 or RyR2. Thus, RyR channelopathies are both of interest because they cause significant human diseases and provide model systems that can be studied to elucidate important structure–function relationships of these ion channels. PMID:20179962

  1. The evolution of vertebrate opioid receptors

    OpenAIRE

    Stevens, Craig W.

    2009-01-01

    The proteins that mediate the analgesic and other effects of opioid drugs and endogenous opioid peptides are known as opioid receptors. Opioid receptors consist of a family of four closely-related proteins belonging to the large superfamily of G-protein coupled receptors. The three types of opioid receptors shown unequivocally to mediate analgesia in animal models are the mu (MOR), delta (DOR), and kappa (KOR) opioid receptor proteins. The role of the fourth member of the opioid receptor fami...

  2. Estrogen-related receptor β (ERRβ) - renaissance receptor or receptor renaissance?

    Science.gov (United States)

    Divekar, Shailaja D; Tiek, Deanna M; Fernandez, Aileen; Riggins, Rebecca B

    2016-01-01

    Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor.

  3. Stargazin Modulation of AMPA Receptors

    Directory of Open Access Journals (Sweden)

    Sana A. Shaikh

    2016-10-01

    Full Text Available Fast excitatory synaptic signaling in the mammalian brain is mediated by AMPA-type ionotropic glutamate receptors. In neurons, AMPA receptors co-assemble with auxiliary proteins, such as stargazin, which can markedly alter receptor trafficking and gating. Here, we used luminescence resonance energy transfer measurements to map distances between the full-length, functional AMPA receptor and stargazin expressed in HEK293 cells and to determine the ensemble structural changes in the receptor due to stargazin. In addition, we used single-molecule fluorescence resonance energy transfer to study the structural and conformational distribution of the receptor and how this distribution is affected by stargazin. Our nanopositioning data place stargazin below the AMPA receptor ligand-binding domain, where it is well poised to act as a scaffold to facilitate the long-range conformational selection observations seen in single-molecule experiments. These data support a model of stargazin acting to stabilize or select conformational states that favor activation.

  4. Cytokine receptors and hematopoietic differentiation.

    Science.gov (United States)

    Robb, L

    2007-10-15

    Colony-stimulating factors and other cytokines signal via their cognate receptors to regulate hematopoiesis. In many developmental systems, inductive signalling determines cell fate and, by analogy with this, it has been postulated that cytokines, signalling via their cognate receptors, may play an instructive role in lineage specification in hematopoiesis. An alternative to this instructive hypothesis is the stochastic or permissive hypothesis. The latter proposes that commitment to a particular hematopoietic lineage is an event that occurs independently of extrinsic signals. It predicts that the role of cytokines is to provide nonspecific survival and proliferation signals. In this review, we look at the role of cytokine receptor signalling in hematopoiesis and consider the evidence for both hypotheses. Data from experiments that genetically manipulate receptor gene expression in vitro or in vivo are reviewed. Experiments in which cytokine receptors were installed in multipotential cells showed that, in some cases, stimulation with the cognate ligand could lead to alterations in lineage output. The creation of genetically manipulated mouse strains demonstrated that cytokine receptors are required for expansion and survival of single lineages but did not reveal a role in lineage commitment. We conclude that hematopoietic differentiation involves mainly stochastic events, but that cytokine receptors also have some instructive role.

  5. Vascular dopamine-I receptors.

    Science.gov (United States)

    Yasunari, K; Kohno, M; Yokokawa, K; Horio, T; Kano, H; Takeda, T

    1995-06-01

    The modulation of dopamine DA1 receptors of cultured rat renal arterial smooth muscle cells by phorbol ester, glucocorticoid and sodium chloride was studied. The extent of [3H]Sch-23390 binding to phorbol ester-treated cell was increased without any change in the dissociation constant (Kd). At a concentration of 10 nmol/l, the synthetic glucocorticoid dexamethasone increased maximum receptor binding (Bmax) but had no effect on the Kd. 100 mmol/l sodium chloride did not change Bmax, but increased the Kd for DA1 receptor. The production of cAMP in response to DA1 receptor stimulation was enhanced without any change of the adenylate cyclase activity. The glucocorticoid effect on DA1 of arterial smooth muscle cells became apparent after hours of incubation in the presence of the steroid and was significantly inhibited by cycloheximide (10 micrograms/ml) and by the glucocorticoid receptor antagonist RU-38486, indicating that the effect required protein synthesis through glucocorticoid receptors. Treatment of cells with 1 mumol/l dexamethasone for 24 h increased basal and DA1-stimulated adenylate cyclase activity. Basal adenylate cyclase was decreased by sodium chloride in a dose-dependent manner. These results suggest differential control of DA1 receptors on vascular smooth muscle cells by protein kinase C, glucocorticoid or sodium chloride.

  6. Nuclear hormone receptors in podocytes

    Directory of Open Access Journals (Sweden)

    Khurana Simran

    2012-09-01

    Full Text Available Abstract Nuclear receptors are a family of ligand-activated, DNA sequence-specific transcription factors that regulate various aspects of animal development, cell proliferation, differentiation, and homeostasis. The physiological roles of nuclear receptors and their ligands have been intensively studied in cancer and metabolic syndrome. However, their role in kidney diseases is still evolving, despite their ligands being used clinically to treat renal diseases for decades. This review will discuss the progress of our understanding of the role of nuclear receptors and their ligands in kidney physiology with emphasis on their roles in treating glomerular disorders and podocyte injury repair responses.

  7. Quantitative receptor radioautography in the study of receptor-receptor interactions in the nucleus tractus solitarii

    Directory of Open Access Journals (Sweden)

    Fior-Chadi D.R.

    1998-01-01

    Full Text Available The nucleus tractus solitarii (NTS in the dorsomedial medulla comprises a wide range of neuropeptides and biogenic amines. Several of them are related to mechanisms of central blood pressure control. Angiotensin II (Ang II, neuropeptide Y (NPY and noradrenaline (NA are found in the NTS cells, as well as their receptors. Based on this observation we have evaluated the modulatory effect of these peptide receptors on a2-adrenoceptors in the NTS. Using quantitative receptor radioautography, we observed that NPY and Ang II receptors decreased the affinity of a2-adrenoceptors for their agonists in the NTS of the rat. Cardiovascular experiments agreed with the in vitro data. Coinjection of a threshold dose of Ang II or of the NPY agonists together with an ED50 dose of adrenergic agonists such as NA, adrenaline and clonidine counteracted the depressor effect produced by the a2-agonist in the NTS. The results provide evidence for the existence of an antagonistic interaction between Ang II at1 receptors and NPY receptor subtypes with the a2-adrenoceptors in the NTS. This receptor interaction may reduce the transduction over the a2-adrenoceptors which can be important in central cardiovascular regulation and in the development of hypertension

  8. Autoimmune NMDA receptor encephalitis.

    Science.gov (United States)

    Lazar-Molnar, Eszter; Tebo, Anne E

    2015-01-01

    Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune disease of the central nervous system (CNS) with prominent neurologic and psychiatric features at disease onset. The disease is associated with the production of autoantibodies to NMDAR, a protein involved in memory function and synaptic plasticity. Affected patients develop a multistage progressive illness with symptoms ranging from memory deficits, seizures and psychosis, to potentially lethal catatonia, and autonomic and breathing instability. The outcome can be much improved with accurate diagnosis and early treatment using adequate immunosuppressive therapy. However, since the neurological and psychiatric symptoms as well as the clinical examination results can be non-specific, the disease is probably under-recognized. Reliable and accurate clinical testing for the identification of NMDAR autoantibodies is crucial for diagnosis, timely treatment selection, and monitoring. Recently, a cell-based indirect immunofluorescent antibody test for the detection of IgG antibodies to NMDAR has become available for diagnostic use. This review highlights the progress and challenges of laboratory testing in the evaluation and management anti-NMDAR encephalitis, and perspectives for the future.

  9. Nuclear Receptor Signaling Atlas (NURSA)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Nuclear Receptor Signaling Atlas (NURSA) is designed to foster the development of a comprehensive understanding of the structure, function, and role in disease...

  10. Anthrax receptors position the spindle.

    Science.gov (United States)

    Minc, Nicolas; Piel, Matthieu

    2013-01-01

    Spindle orientation plays a pivotal role in tissue morphogenesis. An asymmetric anthrax receptor cap is revealed to promote activation of a formin to orient the spindle along the planar cell polarity (PCP) axis in zebrafish dorsal epiblast cells.

  11. [Nucleotide receptors and renal function].

    Science.gov (United States)

    Jankowski, Maciej

    2014-01-01

    Kidney plays a key role in homeostasis of human body. It has heterogenic structure and is characterized by complicated vascular beds and numbers of sympathetic nerves endings. Nucleotides receptors are involved in the regulation of blood flow, a fundamental process for renal function. Plasma is filtrated in renal glomerulus and activity of nucleotides receptors located on cells of glomerular filter modifies the physi- cochemical properties of filter and affects the filtration process. Electrolytes, water and low molecular weight molecules are reabsorbed from tubular fluid or secreted into fluid in proximal and distal tubules. Glomerular filtration rate and activity of tubular processes are regulated via nucleotides receptors by glomerulotubularbalance and tubuloglomerular feedback. Nucleotides receptors are involved in systemic regulation of blood pressure and carbohydrate metabolism.

  12. The lactate receptor, G-protein-coupled receptor 81/hydroxycarboxylic acid receptor 1

    DEFF Research Database (Denmark)

    Morland, Cecilie; Lauritzen, Knut Huso; Puchades, Maja;

    2015-01-01

    We have proposed that lactate is a “volume transmitter” in the brain and underpinned this by showing that the lactate receptor, G-protein-coupled receptor 81 (GPR81, also known as HCA1 or HCAR1), which promotes lipid storage in adipocytes, is also active in the mammalian brain. This includes...... anion channels activated by depolarization. In addition to locally produced lactate, lactate produced by exercising muscle as well as exogenous HCAR1 agonists, e.g., from fruits and berries, might activate the receptor on cerebral blood vessels and brain cells....

  13. An Update on GABAρ Receptors

    OpenAIRE

    Martínez-Delgado, Gustavo; Estrada-Mondragón, Argel; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2010-01-01

    The present review discusses the functional and molecular diversity of GABAρ receptors. These receptors were originally described in the mammalian retina, and their functional role in the visual pathway has been recently elucidated; however new studies on their distribution in the brain and spinal cord have revealed that they are more spread than originally thought, and thus it will be important to determine their physiological contribution to the GABAergic transmission in other areas of the ...

  14. Lysophospholipid receptors in drug discovery

    OpenAIRE

    Kihara, Yasuyuki; Mizuno, Hirotaka; Chun, Jerold

    2014-01-01

    Lysophospholipids (LPs), including lysophosphatidic acid (LPA), sphingosine 1-phospate (S1P), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS), are bioactive lipids that transduce signals through their specific cell-surface G protein-coupled receptors, LPA1–6, S1P1–5, LPI1, and LysoPS1–3, respectively. These LPs and their receptors have been implicated in both physiological and pathophysiological processes such as autoimmune diseases, neurodegenerative diseases, fibrosis, p...

  15. Receptor antibodies as novel therapeutics for diabetes

    DEFF Research Database (Denmark)

    Ussar, Siegfried; Vienberg, Sara Gry; Kahn, C Ronald

    2011-01-01

    Antibodies to receptors can block or mimic hormone action. Taking advantage of receptor isoforms, co-receptors, and other receptor modulating proteins, antibodies and other designer ligands can enhance tissue specificity and provide new approaches to the therapy of diabetes and other diseases....

  16. Receptor-targeted metalloradiopharmaceuticals. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Green, Mark A.

    2000-03-22

    Copper (II) and platinum (II) coordination complexes were prepared and characterized. These complexes were designed to afford structural homology with steroidal and non-steroidal estrogens for possible use as receptor-targeted radiopharmaceuticals. While weak affinity for the estrogen receptor was detectable, none would appear to have sufficient receptor-affinity for estrogen-receptor-targeted imaging or therapy.

  17. 激活素A在细菌性脑膜炎新生儿脑脊液中的变化及其对预后评估的价值%Change of Activin A in Cerebrospinal Fluid of Neonates with Bacterial Meningitis and Its Value for Prognosis Evaluation

    Institute of Scientific and Technical Information of China (English)

    郝丽红; 王琳; 郭静; 周颖; 巴爽; 林书祥

    2012-01-01

    目的 研究新生儿细菌性脑膜炎(BM)脑脊液(CSF)中激活素A( ACT A)水平的变化及其对预后判断的意义.方法 对2010年3月-2011年6月在本院新生儿病房住院的48例确诊BM患儿,进行3~18个月的随访及回顾性分析,分为有并发症和后遗症组(A组)和无并发症和后遗症组(B组).另收集同期住院的非颅内疾病患儿作为对照组(C组).应用EHSA法动态监测3组患儿CSF中ACT A水平.结果 A组患儿急性期CSF中ACT A水平为(544.39±149.62) ng·L-1,B组CSF中ACT A水平为(480.82±128.24) ng·L-1,二组间差异无统计学意义,但2组均高于C组[(181.06±45.20) ng·L-1](Pa<0.01).治疗1周,A组CSF中ACT A水平为(315.84±86.35) ng·L-1、B组为(338.25±99.43) ng·L-1,2组较治疗前显著下降(Pa<0.05),但2组间差异无统计学意义(P=0.432).治疗2周,A组CSF中ACT A水平为(188.19±43.38) ng·L-1,B组为(203.86±50.73) ng·L-1,2组差异无统计学意义(P=0.281).治疗3周,A组CSF中ACT A水平为(107.65±17.65)ng·L-1,B组为( 169.36±28.90)ng·L-1,A组明显低于B组(P =0.000).治疗4周,A组CSF中ACT A水平为(98.54±28.54) ng·L-1,B组为(181.84 ±35.01)ng·L-1,A组显著低于B组(P=0.000).结论 ACT A参与新生儿BM的发病过程,动态检测CSF中ACT A水平,对评估新生儿BM的预后,可能具有重要价值.%Abstract; Objective To evaluate the changes of activin A( ACT A) level in cerebrospinal fluid(CSF) in neonatal bacterial meningitis and its clinical value for prognosis evaluation. Methods Forty - eight neonatal bacterial meningitis in Tianjin Children's Hospital from Mar. 2010 to Jun. 2011 were visited for 3-18 months and analyzed retrospectively. All the patients were divided into 2 groups: neonatal bacterial meningitis with the complications and (or) sequelae group (group A) ,without the complications and sequelae group (group B) ,and the children without brain disease were selected as control group (group C). The levels of ACT A in cerebrospinal

  18. Estrogen receptors in breast carcinoma.

    Science.gov (United States)

    Huaman, A

    1979-11-01

    On the basis of estrogen receptor assays, breast carcinomas are presently classified as estrogen-dependent tumors, which respond to endocrine therapy, and autonomous tumors, for which endocrine therapy is useless. This paper presents a short review of the biochemical principles of estrogen dependence, the procedures used to determine estrogen receptors, and the clinical applications of the findings of these assay procedures. Biobhemically, the estroogen dependence of normal breast cells is explained as a biochemical reaction occurring between the circulating estradiol and the breast cell, which occurs in 3 steps: 1) circulating estradiol penetrates the cellular membrane by passive diffusion, followed by 2) combining of estradiol with the estrogen-binding protein (estrophilin) and formation of an estrogen receptor complex which undergoes activation and translocation into the nucleus, to result in 3) the activated steroid receptor which combines with the nuclear charomatin and stimulates ribonucleic acid synthesis for the formation of estradiol binding proteins or estradiol receptors. The cytosol method of Wittliff et al. is described in brief and entails radioactive competitive analysis; the other available laboratory procedure is immunofluorescence of tumor sections. Quantification of estrogen receptor content can be used clinically to decide on ablative endocrine therapy, to determine the effectiveness of anti-estrogen administration, to determine the primary site of metastatic carcinoma, and as a screenng device.

  19. Regulatory roles of bone morphogenetic proteins and glucocorticoids in catecholamine production by rat pheochromocytoma cells.

    Science.gov (United States)

    Kano, Yoshihiro; Otsuka, Fumio; Takeda, Masaya; Suzuki, Jiro; Inagaki, Kenichi; Miyoshi, Tomoko; Miyamoto, Manabu; Otani, Hiroyuki; Ogura, Toshio; Makino, Hirofumi

    2005-12-01

    We here report a new physiological system that governs catecholamine synthesis involving bone morphogenetic proteins (BMPs) and activin in the rat pheochromocytoma cell line, PC12. BMP type I receptors, including activin receptor-like kinase-2 (ALK-2) (also referred to as ActRIA) and ALK-3 (BMPRIA), both type II receptors, ActRII and BMPRII, as well as the ligands BMP-2, -4, and -7 and inhibin/activin subunits were expressed in PC12 cells. PC12 cells predominantly secrete dopamine, whereas noradrenaline and adrenaline production is negligible. BMP-2, -4, -6, and -7 and activin A each suppressed dopamine and cAMP synthesis in a dose-dependent fashion. The BMP ligands also decreased 3,4-dihydroxyphenylalanine decarboxylase mRNA expression, whereas activin suppressed tyrosine hydroxylase expression. BMPs induced both Smad1/5/8 phosphorylation and Tlx2-Luc activation, whereas activin stimulated 3TP-Luc activity and p38 MAPK phosphorylation. ERK signaling was not affected by BMPs or activin. Dexamethasone enhanced catecholamine synthesis, accompanying increases in tyrosine hydroxylase and 3,4-dihydroxyphenylalanine decarboxylase transcription without cAMP accumulation. In the presence of dexamethasone, BMPs and activin failed to reduce dopamine as well as cAMP production. In addition, dexamethasone modulated mitotic suppression of PC12 induced by BMPs in a ligand-dependent manner. Furthermore, intracellular BMP signaling was markedly suppressed by dexamethasone treatment and the expression of ALK-2, ALK-3, and BMPRII was significantly inhibited by dexamethasone. Collectively, the endogenous BMP/activin system plays a key role in the regulation of catecholamine production. Controlling activity of the BMP system may be critical for glucocorticoid-induced catecholamine synthesis by adrenomedullar cells.

  20. Nuclear Receptors, RXR, and the Big Bang.

    Science.gov (United States)

    Evans, Ronald M; Mangelsdorf, David J

    2014-03-27

    Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism.

  1. Prognostic Value of Estrogen Receptor alpha and Progesterone Receptor Conversion in Distant Breast Cancer Metastases

    NARCIS (Netherlands)

    Hoefnagel, Laurien D. C.; Moelans, Cathy B.; Meijer, S. L.; van Slooten, Henk-Jan; Wesseling, Pieter; Wesseling, Jelle; Westenend, Pieter J.; Bart, Joost; Seldenrijk, Cornelis A.; Nagtegaal, Iris D.; Oudejans, Joost; van der Valk, Paul; van Gils, Carla H.; van der Wall, Elsken; van Diest, Paul J.

    2012-01-01

    BACKGROUND: Changes in the receptor profile of primary breast cancers to their metastases (receptor conversion) have been described for the estrogen receptor alpha (ER alpha) and progesterone receptor (PR). The purpose of this study was to evaluate the impact of receptor conversion for ER alpha and

  2. Neurotrophins and their receptors in inflammation

    Institute of Scientific and Technical Information of China (English)

    NellyFROSSARD; CharlesADVENIER

    2004-01-01

    The neurotrophin family has recently been in volved ininflammatory and remodelling processes occurring in chronic inflammatory diseases, in particular in asthma. Nerve growth fac-tor (NGF) is a high molecular weight peptide that belongs to the neurotrophin family. It is synthesized by various structural and inflammatory cells and activates two types of receptors, the TrkA (tropomyosin-receptor kinase A) receptor and the p75NTR receptor, in the death receptor family. NGF was first studied for

  3. Toll-like receptors in neonatal sepsis.

    LENUS (Irish Health Repository)

    O'Hare, Fiona M

    2013-06-01

    Toll-like receptors are vital transmembrane receptors that initiate the innate immune response to many micro-organisms. The discovery of these receptors has improved our understanding of host-pathogen interactions, and these receptors play an important role in the pathogenesis of multiple neonatal conditions such as sepsis and brain injury. Toll-like receptors, especially TLRs 2 and 4, are associated with necrotizing enterocolitis, periventricular leukomalacia and sepsis.

  4. 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.

  5. Purinergic Receptors in Ocular Inflammation

    Directory of Open Access Journals (Sweden)

    Ana Guzman-Aranguez

    2014-01-01

    Full Text Available Inflammation is a complex process that implies the interaction between cells and molecular mediators, which, when not properly “tuned,” can lead to disease. When inflammation affects the eye, it can produce severe disorders affecting the superficial and internal parts of the visual organ. The nucleoside adenosine and nucleotides including adenine mononucleotides like ADP and ATP and dinucleotides such as P1,P4-diadenosine tetraphosphate (Ap4A, and P1,P5-diadenosine pentaphosphate (Ap5A are present in different ocular locations and therefore they may contribute/modulate inflammatory processes. Adenosine receptors, in particular A2A adenosine receptors, present anti-inflammatory action in acute and chronic retinal inflammation. Regarding the A3 receptor, selective agonists like N6-(3-iodobenzyl-5′-N-methylcarboxamidoadenosine (CF101 have been used for the treatment of inflammatory ophthalmic diseases such as dry eye and uveoretinitis. Sideways, diverse stimuli (sensory stimulation, large intraocular pressure increases can produce a release of ATP from ocular sensory innervation or after injury to ocular tissues. Then, ATP will activate purinergic P2 receptors present in sensory nerve endings, the iris, the ciliary body, or other tissues surrounding the anterior chamber of the eye to produce uveitis/endophthalmitis. In summary, adenosine and nucleotides can activate receptors in ocular structures susceptible to suffer from inflammatory processes. This involvement suggests the possible use of purinergic agonists and antagonists as therapeutic targets for ocular inflammation.

  6. Ionotropic glutamate receptors & CNS disorders.

    Science.gov (United States)

    Bowie, Derek

    2008-04-01

    Disorders of the central nervous system (CNS) are complex disease states that represent a major challenge for modern medicine. Although aetilogy is often unknown, it is established that multiple factors such as defects in genetics and/or epigenetics, the environment as well as imbalance in neurotransmitter receptor systems are all at play in determining an individual's susceptibility to disease. Gene therapy is currently not available and therefore, most conditions are treated with pharmacological agents that modify neurotransmitter receptor signaling. Here, I provide a review of ionotropic glutamate receptors (iGluRs) and the roles they fulfill in numerous CNS disorders. Specifically, I argue that our understanding of iGluRs has reached a critical turning point to permit, for the first time, a comprehensive re-evaluation of their role in the cause of disease. I illustrate this by highlighting how defects in AMPA receptor (AMPAR) trafficking are important to fragile X mental retardation and ectopic expression of kainate receptor (KAR) synapses contributes to the pathology of temporal lobe epilepsy. Finally, I discuss how parallel advances in studies of other neurotransmitter systems may allow pharmacologists to work towards a cure for many CNS disorders rather than developing drugs to treat their symptoms.

  7. Brain CB₂ Receptors: Implications for Neuropsychiatric Disorders.

    Science.gov (United States)

    Roche, Michelle; Finn, David P

    2010-08-10

    Although previously thought of as the peripheral cannabinoid receptor, it is now accepted that the CB₂ receptor is expressed in the central nervous system on microglia, astrocytes and subpopulations of neurons. Expression of the CB₂ receptor in the brain is significantly lower than that of the CB₁ receptor. Conflicting findings have been reported on the neurological effects of pharmacological agents targeting the CB₂ receptor under normal conditions. Under inflammatory conditions, CB₂ receptor expression in the brain is enhanced and CB2 receptor agonists exhibit potent anti-inflammatory effects. These findings have prompted research into the CB₂ receptor as a possible target for the treatment of neuroinflammatory and neurodegenerative disorders. Neuroinflammatory alterations are also associated with neuropsychiatric disorders and polymorphisms in the CB₂ gene have been reported in depression, eating disorders and schizophrenia. This review will examine the evidence to date for a role of brain CB₂ receptors in neuropsychiatric disorders.

  8. Identification and mechanism of ABA receptor antagonism

    Energy Technology Data Exchange (ETDEWEB)

    Melcher, Karsten; Xu, Yong; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Chinnusamy, Viswanathan; Suino-Powell, Kelly M; Kovach, Amanda; Tham, Fook S.; Cutler, Sean R.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H. Eric (NU Sinapore); (Van Andel); (UCR)

    2010-11-11

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands.

  9. Effects of tripterygium wilfordii polyglucoside on expression of Activin A and influence of transdifferentiation in renal tubulointerstitium of rats with diabetic nephropathy%雷公藤多苷对糖尿病肾病大鼠肾小管间质激活素A表达及转分化的影响

    Institute of Scientific and Technical Information of China (English)

    赵晨光; 于为民; 任小军; 张巍; 李慧

    2014-01-01

    Objective To explore the effects of tripterygium wilfordii polyglucoside (TWP) on expression of Activin A (Act-A) and influence of transdifferentiation in renal tubulointerstitium of rats with diabetes nephropathy (DN).Methods A total of 40 male Wistar rats were randomly divided into normal control,DN model,irbesartan treatment and TWP treatment groups (n =10 each).The animal model of DN was established by an injection of streptozotocin.After modeling,irbesartan treatment and TWP treatment groups received an intragastric injection of corresponding drugs.The body weights were recorded and the 24 h Pro quantitative levels detected at Weeks 4,8,12 and 16 respectively.After sacrificing at Week 16,serum creatinine (Scr) was detected.The renal tissues were excised and examined after HE and PAS staining.The expressions of Act-A,alpha-smooth muscle actin (α-SMA),collagen type Ⅳ (Co-Ⅳ) and E-cad in renal tubulointerstitium were detected by immunohistochemistry.And the expressions of Act-A,α-SMA,Co-Ⅳand mRNA of E-cad in renal tissue were detected by real-time quantitative fluorescent polymerase chain reaction (PCR).Results Compared with DN model group,24 hPro ((67.1 ± 9.6),(61.8 ± 8.0) vs (158.3 ± 13.3) mg),quantitative Scr ((31.7 ± 4.1),(32.6 ± 6.2) vs (55.3 ± 8.9) μmol/L) and renal hypertrophic index ((9.14 ± 0.65),(7.50 ± 0.34) vs (11.28 ± 0.70) mg/g) of irbesartan treatment and TWP treatment groups decreased obviously at Week 16 (all P < 0.05).However,no statistical significance existed between irbesartan treatment and TWP treatment groups.The body weights of irbesartan treatment and TWP treatment groups increased versus DN model group.Pathological sections showed that lesion degree of renal tubulointerstitium became alleviated in each group.Yet no statistical significance existed between irbesartan treatment and TWP treatment groups.Both immunohistochemistry and real-time quantitative fluorescent PCR showed that the expressions of Act-A,α-SMA and Co

  10. Cannabinoids, cannabinoid receptors and tinnitus.

    Science.gov (United States)

    Smith, Paul F; Zheng, Yiwen

    2016-02-01

    One hypothesis suggests that tinnitus is a form of sensory epilepsy, arising partly from neuronal hyperactivity in auditory regions of the brain such as the cochlear nucleus and inferior colliculus. Although there is currently no effective drug treatment for tinnitus, anti-epileptic drugs are used in some cases as a potential treatment option. There is increasing evidence to suggest that cannabinoid drugs, i.e. cannabinoid receptor agonists, can also have anti-epileptic effects, at least in some cases and in some parts of the brain. It has been reported that cannabinoid CB1 receptors and the endogenous cannabinoid, 2-arachidonylglycerol (2-AG), are expressed in the cochlear nucleus and that they are involved in the regulation of plasticity. This review explores the question of whether cannabinoid receptor agonists are likely to be pro- or anti-epileptic in the cochlear nucleus and therefore whether cannabinoids and Cannabis itself are likely to make tinnitus better or worse.

  11. Are olfactory receptors really olfactive?

    DEFF Research Database (Denmark)

    Giorgi, Franco; Maggio, Roberto; Bruni, Luis Emilio

    2011-01-01

    Any living organism interacts with and responds specifically to environmental molecules by expressing specific olfactory receptors. This specificity will be first examined in causal terms with particular emphasis on the mechanisms controlling olfactory gene expression, cell-to-cell interactions...... and odor-decoding processes. However, this type of explanation does not entirely justify the role olfactory receptors have played during evolution, since they are also expressed ectopically in different organs and/or tissues. Homologous olfactory genes have in fact been found in such diverse cells and....../or organs as spermatozoa, testis and kidney where they are assumed to act as chemotactic sensors or renin modulators. To justify their functional diversity, homologous olfactory receptors are assumed to share the same basic role: that of conferring a self-identity to cells or tissues under varying...

  12. An Update on GABAρ Receptors

    Science.gov (United States)

    Martínez-Delgado, Gustavo; Estrada-Mondragón, Argel; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2010-01-01

    The present review discusses the functional and molecular diversity of GABAρ receptors. These receptors were originally described in the mammalian retina, and their functional role in the visual pathway has been recently elucidated; however new studies on their distribution in the brain and spinal cord have revealed that they are more spread than originally thought, and thus it will be important to determine their physiological contribution to the GABAergic transmission in other areas of the central nervous system. In addition, molecular modeling has revealed peculiar traits of these receptors that have impacted on the interpretations of the latest pharmacolgical and biophysical findings. Finally, sequencing of several vertebrate genomes has permitted a comparative analysis of the organization of the GABAρ genes. PMID:21629448

  13. Cytokine-Leukotriene Receptor Interactions

    Directory of Open Access Journals (Sweden)

    Marek Rola-Pleszczynski

    2007-01-01

    Full Text Available Biochemical and pharmacological studies have identified the structure of leukotrienes, the pathways that lead to their synthesis, and the signaling events they trigger when they interact with their cognate receptors. A privileged interaction exists between these lipid mediators and another group of molecules essential for inflammation and immune modulation, namely, cytokines. Whereas leukotrienes can trigger the synthesis and release of selected cytokines in distinct cell populations, many cytokines can affect cellular responsiveness to leukotrienes by modulating leukotriene receptor expression. As we progressively begin to unravel these complex interactions, new areas of cell-cell communication and eventual therapeutic interventions will emerge.

  14. Nuclear receptors and nonalcoholic fatty liver disease.

    Science.gov (United States)

    Cave, Matthew C; Clair, Heather B; Hardesty, Josiah E; Falkner, K Cameron; Feng, Wenke; Clark, Barbara J; Sidey, Jennifer; Shi, Hongxue; Aqel, Bashar A; McClain, Craig J; Prough, Russell A

    2016-09-01

    Nuclear receptors are transcription factors which sense changing environmental or hormonal signals and effect transcriptional changes to regulate core life functions including growth, development, and reproduction. To support this function, following ligand-activation by xenobiotics, members of subfamily 1 nuclear receptors (NR1s) may heterodimerize with the retinoid X receptor (RXR) to regulate transcription of genes involved in energy and xenobiotic metabolism and inflammation. Several of these receptors including the peroxisome proliferator-activated receptors (PPARs), the pregnane and xenobiotic receptor (PXR), the constitutive androstane receptor (CAR), the liver X receptor (LXR) and the farnesoid X receptor (FXR) are key regulators of the gut:liver:adipose axis and serve to coordinate metabolic responses across organ systems between the fed and fasting states. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and may progress to cirrhosis and even hepatocellular carcinoma. NAFLD is associated with inappropriate nuclear receptor function and perturbations along the gut:liver:adipose axis including obesity, increased intestinal permeability with systemic inflammation, abnormal hepatic lipid metabolism, and insulin resistance. Environmental chemicals may compound the problem by directly interacting with nuclear receptors leading to metabolic confusion and the inability to differentiate fed from fasting conditions. This review focuses on the impact of nuclear receptors in the pathogenesis and treatment of NAFLD. Clinical trials including PIVENS and FLINT demonstrate that nuclear receptor targeted therapies may lead to the paradoxical dissociation of steatosis, inflammation, fibrosis, insulin resistance, dyslipidemia and obesity. Novel strategies currently under development (including tissue-specific ligands and dual receptor agonists) may be required to separate the beneficial effects of nuclear receptor activation from unwanted metabolic

  15. Human Induced Pluripotent Stem Cell-Derived Cardiac Progenitor Cells in Phenotypic Screening: A Transforming Growth Factor-β Type 1 Receptor Kinase Inhibitor Induces Efficient Cardiac Differentiation.

    Science.gov (United States)

    Drowley, Lauren; Koonce, Chad; Peel, Samantha; Jonebring, Anna; Plowright, Alleyn T; Kattman, Steven J; Andersson, Henrik; Anson, Blake; Swanson, Bradley J; Wang, Qing-Dong; Brolen, Gabriella

    2016-02-01

    Several progenitor cell populations have been reported to exist in hearts that play a role in cardiac turnover and/or repair. Despite the presence of cardiac stem and progenitor cells within the myocardium, functional repair of the heart after injury is inadequate. Identification of the signaling pathways involved in the expansion and differentiation of cardiac progenitor cells (CPCs) will broaden insight into the fundamental mechanisms playing a role in cardiac homeostasis and disease and might provide strategies for in vivo regenerative therapies. To understand and exploit cardiac ontogeny for drug discovery efforts, we developed an in vitro human induced pluripotent stem cell-derived CPC model system using a highly enriched population of KDR(pos)/CKIT(neg)/NKX2.5(pos) CPCs. Using this model system, these CPCs were capable of generating highly enriched cultures of cardiomyocytes under directed differentiation conditions. In order to facilitate the identification of pathways and targets involved in proliferation and differentiation of resident CPCs, we developed phenotypic screening assays. Screening paradigms for therapeutic applications require a robust, scalable, and consistent methodology. In the present study, we have demonstrated the suitability of these cells for medium to high-throughput screens to assess both proliferation and multilineage differentiation. Using this CPC model system and a small directed compound set, we identified activin-like kinase 5 (transforming growth factor-β type 1 receptor kinase) inhibitors as novel and potent inducers of human CPC differentiation to cardiomyocytes. Significance: Cardiac disease is a leading cause of morbidity and mortality, with no treatment available that can result in functional repair. This study demonstrates how differentiation of induced pluripotent stem cells can be used to identify and isolate cell populations of interest that can translate to the adult human heart. Two separate examples of phenotypic

  16. Slamf receptors : Modulators of Phagocyte Immune Responses

    NARCIS (Netherlands)

    Van Driel, Boaz Job

    2015-01-01

    Signaling Lymphocyte Activation Molecule family (Slamf) receptors can operate in three distinct modes. Slamf receptors can dictate the extent of immune responses, thereby maneuvering immunity to the optimal zone between immunopathology or autoimmunity and weak, ineffective immune responses. A second

  17. 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

  18. Cannabinoid receptor localization in brain

    Energy Technology Data Exchange (ETDEWEB)

    Herkenham, M.; Lynn, A.B.; Little, M.D.; Johnson, M.R.; Melvin, L.S.; de Costa, B.R.; Rice, K.C. (National Institute of Mental Health, Bethesda, MD (USA))

    1990-03-01

    (3H)CP 55,940, a radiolabeled synthetic cannabinoid, which is 10-100 times more potent in vivo than delta 9-tetrahydrocannabinol, was used to characterize and localize a specific cannabinoid receptor in brain sections. The potencies of a series of natural and synthetic cannabinoids as competitors of (3H)CP 55,940 binding correlated closely with their relative potencies in several biological assays, suggesting that the receptor characterized in our in vitro assay is the same receptor that mediates behavioral and pharmacological effects of cannabinoids, including human subjective experience. Autoradiography of cannabinoid receptors in brain sections from several mammalian species, including human, reveals a unique and conserved distribution; binding is most dense in outflow nuclei of the basal ganglia--the substantia nigra pars reticulata and globus pallidus--and in the hippocampus and cerebellum. Generally high densities in forebrain and cerebellum implicate roles for cannabinoids in cognition and movement. Sparse densities in lower brainstem areas controlling cardiovascular and respiratory functions may explain why high doses of delta 9-tetrahydrocannabinol are not lethal.

  19. Are olfactory receptors really olfactive?

    DEFF Research Database (Denmark)

    Giorgi, Franco; Maggio, Roberto; Bruni, Luis Emilio

    2011-01-01

    Any living organism interacts with and responds specifically to environmental molecules by expressing specific olfactory receptors. This specificity will be first examined in causal terms with particular emphasis on the mechanisms controlling olfactory gene expression, cell-to-cell interactions a...

  20. Hormone receptors in breast cancer

    NARCIS (Netherlands)

    Suijkerbuijk, K. P M; van der Wall, E.; van Diest, P. J.

    2016-01-01

    Steroid hormone receptors are critical for the growth and development of breast tissue as well as of breast cancer. The importance of the role estrogens in breast cancer has been delineated for more than 100 years. The analysis of its expression has been used not only to classify breast cancers but

  1. Dopamine Receptor Availability in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-01-01

    Full Text Available Striatal dopamine (D2 receptor availability was determined by iodobenzamide brain SPECT, before and 3 months after methylphenidate (MPH therapy, in 9 children (mean age, 9.8 years with attention deficit hyperactivity disorder (ADHD examined at Gazi University, Ankara, Turkey.

  2. Emerging GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2011-01-01

    Introduction: Recently, glucagon-like peptide-1 receptor (GLP-1R) agonists have become available for the treatment of type 2 diabetes. These agents exploit the physiological effects of GLP-1, which is able to address several of the pathophysiological features of type 2 diabetes. GLP-1R agonists...

  3. Serotonin receptors as cardiovascular targets

    NARCIS (Netherlands)

    C.M. Villalón (Carlos); P.A.M. de Vries (Peter); P.R. Saxena (Pramod Ranjan)

    1997-01-01

    textabstractSerotonin exerts complex effects in the cardiovascular system, including hypotension or hypertension, vasodilatation or vasoconstriction, and/or bradycardia or tachycardia; the eventual response depends primarily on the nature of the 5-HT receptors involved. In the light of current 5-HT

  4. Estrogen Receptor Driven Inhibitor Synthesis

    Science.gov (United States)

    2006-09-01

    Engstrom O, Ohman L, Greene GL, Gustaffson JA, Carlquist M. Molecular basis of agonism and antagonism in the oestrogen receptor. Nature 389, 753-758...oxidatively modified proteins in Bacillus subtilis, Mol. Microbiol. 58 (2005) 409–425. [7] K. Tyagarajan, E. Pretzer, J.E. Wiktorowicz, Thiol-reactive dyes

  5. NMDA receptors and memory encoding.

    Science.gov (United States)

    Morris, Richard G M

    2013-11-01

    It is humbling to think that 30 years have passed since the paper by Collingridge, Kehl and McLennan showing that one of Jeff Watkins most interesting compounds, R-2-amino-5-phosphonopentanoate (d-AP5), blocked the induction of long-term potentiation in vitro at synapses from area CA3 of the hippocampus to CA1 without apparent effect on baseline synaptic transmission (Collingridge et al., 1983). This dissociation was one of the key triggers for an explosion of interest in glutamate receptors, and much has been discovered since that collectively contributes to our contemporary understanding of glutamatergic synapses - their biophysics and subunit composition, of the agonists and antagonists acting on them, and their diverse functions in different networks of the brain and spinal cord. It can be fairly said that Collingridge et al.'s (1983) observation was the stimulus that has led, on the one hand, to structural biological work at the atomic scale describing the key features of NMDA receptors that enables their coincidence function to happen; and, on the other, to work with whole animals investigating the contributions that calcium signalling via this receptor can have on rhythmical activities controlled by spinal circuits, memory encoding in the hippocampus (the topic of this article), visual cortical plasticity, sensitization in pain, and other functions. In this article, I lay out how my then interest in long-term potentiation (LTP) as a model of memory enabled me to recognise the importance of Collingridge et al.'s discovery - and how I and my colleagues endeavoured to take things forward in the area of learning and memory. This is in some respects a personal story, and I tell it as such. The idea that NMDA receptor activation is essential for memory encoding, though not for storage, took time to develop and to be accepted. Along the way, there have been confusions, challenges, and surprises surrounding the idea that activation of NMDA receptors can

  6. Amide-based Fluorescent Macrocyclic Anion Receptors

    Institute of Scientific and Technical Information of China (English)

    ZENG, Zhen-Ya(曾振亚); XU, Kuo-Xi(徐括喜); HE, Yong-Bing(何永炳); LIU, Shun-Ying(刘顺英); WU, Jin-Long(吴进龙); WEI, Lan-Hua(隗兰华); MENG, Ling-Zhi(孟令芝)

    2004-01-01

    Two fluorescent anion receptors (1 and 2) based on amide macrocycle were synthesized and corresponding fluorescence quenching induced by anion complexation was observed in different degree. Receptors form 1: 1 complexes with anions by hydrogen bonding interactions. Receptor 1 bound anions in the order of F->Cl->H2PO4->CH3COO->>Br-, I- and receptor 2 showed high selectivity to F- over other anions.

  7. Endogenous ion channel complexes: the NMDA receptor.

    Science.gov (United States)

    Frank, René A W

    2011-06-01

    Ionotropic receptors, including the NMDAR (N-methyl-D-aspartate receptor) mediate fast neurotransmission, neurodevelopment, neuronal excitability and learning. In the present article, the structure and function of the NMDAR is reviewed with the aim to condense our current understanding and highlight frontiers where important questions regarding the biology of this receptor remain unanswered. In the second part of the present review, new biochemical and genetic approaches for the investigation of ion channel receptor complexes will be discussed.

  8. Neuroexcitatory Drug Receptors in Mammals and Invertebrates

    Science.gov (United States)

    1990-03-16

    several animal species investigated. We identified the codfish as having a single polypeptide/gene for CABA -A receptors, as compared to 10-15 different...through blocking of CABA receptor functions. The CABA receptor-chloride channel system is important in wide-spread regions of the mammalian nervous... CABA receptor distribution was quantitated and mapped (14). For this analysis, we employed an image analyzer purchased by Drs. Olsen and de Vellis under

  9. Benzodiazepine receptor antagonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C

    2004-01-01

    Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy....

  10. Mannose receptor-targeted vaccines.

    Science.gov (United States)

    Keler, Tibor; Ramakrishna, Venky; Fanger, Michael W

    2004-12-01

    Targeting antigens to endocytic receptors on professional antigen-presenting cells (APCs) represents an attractive strategy to enhance the efficacy of vaccines. Such APC-targeted vaccines have an exceptional ability to guide exogenous protein antigens into vesicles that efficiently process the antigen for major histocompatibility complex class I and class II presentation. Efficient targeting not only requires high specificity for the receptor that is abundantly expressed on the surface of APCs, but also the ability to be rapidly internalised and loaded into compartments that contain elements of the antigen-processing machinery. The mannose receptor (MR) and related C-type lectin receptors are particularly designed to sample antigens (self and non-self), much like pattern recognition receptors, to integrate the innate with adaptive immune responses. In fact, a variety of approaches involving delivery of antigens to the MR have demonstrated effective induction of potent cellular and humoral immune responses. Yet, although several lines of evidence in diverse experimental systems attest to the efficacy of targeted vaccine strategies, it is becoming increasingly clear that additional signals, such as those afforded by adjuvants, may be critical to elicit sustained immunity. Therefore, MR-targeted vaccines are likely to be most efficacious in vivo when combined with agents that elicit complementary activation signals. Certainly, a better understanding of the mechanism associated with the induction of immune responses as a result of targeting antigens to the MR, will be important in exploiting MR-targeted vaccines not only for mounting immune defenses against cancer and infectious disease, but also for specific induction of tolerance in the treatment of autoimmune disease.

  11. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, BRK; Korte, SM; Buwalda, B; la Fleur, SE; Bohus, B; Luiten, PGM

    1998-01-01

    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  12. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, B.R.; Korte, S.M.; Buwalda, B.; Fleur, la S.E.; Bohus, B.; Luiten, P.G.

    1998-01-01

    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  13. The brain mineralocorticoid receptor and stress resilience

    NARCIS (Netherlands)

    ter Heegde, Freija; De Rijk, Roel H.; Vinkers, Christiaan H.

    2015-01-01

    Stress exposure activates the HPA-axis and results in the release of corticosteroids which bind to two receptor types in the brain: the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). While the role of the GR in stress reactivity has been extensively studied, the MR has receive

  14. The brain mineralocorticoid receptor and stress resilience

    NARCIS (Netherlands)

    ter Heegde, Freija; De Rijk, Roel H.; Vinkers, Christiaan H.

    Stress exposure activates the HPA-axis and results in the release of corticosteroids which bind to two receptor types in the brain: the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). While the role of the GR in stress reactivity has been extensively studied, the MR has

  15. 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...

  16. Imaging of receptors in clinical neurosciences

    NARCIS (Netherlands)

    Korf, J

    This article deals with the question why should one determine receptors in the brain with positron and single photon emission tomography (PET and SPECT, respectively). Radiopharmaceuticals for a wide variety of receptors are available now. Receptors studies with PET and SPECT have thus far focused

  17. A new family of insect tyramine receptors

    DEFF Research Database (Denmark)

    Cazzamali, Giuseppe; Klærke, Dan Arne; Grimmelikhuijzen, Cornelis J P

    2005-01-01

    in the genomic databases from the malaria mosquito Anopheles gambiae and the honeybee Apis mellifera. These four tyramine or tyramine-like receptors constitute a new receptor family that is phylogenetically distinct from the previously identified insect octopamine/tyramine receptors. The Drosophila tyramine...

  18. Estrogen receptors in human vaginal tissue

    NARCIS (Netherlands)

    Wiegerinck, M.A.H.M.; Poortman, J.; Agema, A.R.; Thijssen, J.H.H.

    1980-01-01

    The presence of specific estrogen receptors could be demonstrated in vaginal tissue, obtained during operation from 38 women, age 27–75 yr. In 23 premenopausal women the receptor concentration in the vaginal tissue varied between 12 and 91 fmol/mg protein, no significant difference in the receptor

  19. The Human Laminin Receptor is a Member of the Integrin Family of Cell Adhesion Receptors

    Science.gov (United States)

    Gehlsen, Kurt R.; Dillner, Lena; Engvall, Eva; Ruoslahti, Erkki

    1988-09-01

    A receptor for the adhesive basement membrane protein, laminin, was isolated from human glioblastoma cells by affinity chromatography on laminin. This receptor has a heterodimeric structure similar to that of receptors for other extracellular matrix proteins such as fibronectin and vitronectin. Incorporation of the laminin receptor into liposomal membranes makes it possible for liposomes to attach to surfaces coated with laminin. The receptor liposomes also attached to some extent to surfaces coated with fibronectin, but not with other matrix proteins. These properties identify the laminin receptor as a member of the integrin family of cell adhesion receptors.

  20. 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.

  1. Venus Kinase Receptors: prospects in signalling and biological functions of these invertebrate receptors

    OpenAIRE

    Colette eDissous; Marion eMorel; Mathieu eVanderstraete

    2014-01-01

    Venus Kinase Receptors (VKRs) form a family of invertebrate receptor tyrosine kinases (RTKs) initially discovered in the parasitic platyhelminth Schistosoma mansoni. VKRs are single transmembrane receptors which contain an extracellular Venus Flytrap (VFT) structure similar to the ligand binding domain of G Protein Coupled Receptors of class C, and an intracellular Tyrosine Kinase domain close to that of Insulin Receptors. VKRs are found in a large variety of invertebrates from cnidarians to ...

  2. Discoidin Domain Receptors Role in Human Diseases

    Directory of Open Access Journals (Sweden)

    Iker BADIOLA

    2011-11-01

    Full Text Available Discoidin Domain Receptor 1 and Discodin Domain Receptor 2 are the two only members of the DDR family. The DDR family is a Tyrosine Kinase Receptor (TKR family with some peculiarities compared with other Tyrosine Kinase Receptors such as their natural ligand; which in this case is the fibrillar collagen; or the slow phosphorylation pattern. These peculiarities confer a special role to the receptors present in many diseases development processes as cancer, cirrhosis or lung fibrosis. In this review it is described the overview of the DDRs structure and their role in the different disease development and the possibility to consider them as therapeutic targets.

  3. Novel receptors for bacterial protein toxins.

    Science.gov (United States)

    Schmidt, Gudula; Papatheodorou, Panagiotis; Aktories, Klaus

    2015-02-01

    While bacterial effectors are often directly introduced into eukaryotic target cells by various types of injection machines, toxins enter the cytosol of host cells from endosomal compartments or after retrograde transport via Golgi from the ER. A first crucial step of toxin-host interaction is receptor binding. Using optimized protocols and new methods novel toxin receptors have been identified, including metalloprotease ADAM 10 for Staphylococcus aureus α-toxin, laminin receptor Lu/BCAM for Escherichia coli cytotoxic necrotizing factor CNF1, lipolysis stimulated lipoprotein receptor (LSR) for Clostridium difficile transferase CDT and low-density lipoprotein receptor-related protein (LRP) 1 for Clostridium perfringens TpeL toxin.

  4. Evolutionary vignettes of natural killer cell receptors.

    Science.gov (United States)

    Sambrook, Jennifer G; Beck, Stephan

    2007-10-01

    The discovery of novel immune receptors has led to a recent renaissance of research into the innate immune system, following decades of intense research of the adaptive immune system. Of particular interest has been the discovery of the natural killer (NK) cell receptors which, depending on type, interact with classical or non-classical MHC class I antigens of the adaptive immune system, thus functioning at the interface of innate and adaptive immunity. Here, we review recent progress with respect to two such families of NK receptors, the killer immunoglobulin-like receptors (KIRs) and the killer cell lectin-like receptors (KLRs), and attempt to trace their evolution across vertebrates.

  5. Sugars, Sweet Taste Receptors, and Brain Responses.

    Science.gov (United States)

    Lee, Allen A; Owyang, Chung

    2017-06-24

    Sweet taste receptors are composed of a heterodimer of taste 1 receptor member 2 (T1R2) and taste 1 receptor member 3 (T1R3). Accumulating evidence shows that sweet taste receptors are ubiquitous throughout the body, including in the gastrointestinal tract as well as the hypothalamus. These sweet taste receptors are heavily involved in nutrient sensing, monitoring changes in energy stores, and triggering metabolic and behavioral responses to maintain energy balance. Not surprisingly, these pathways are heavily regulated by external and internal factors. Dysfunction in one or more of these pathways may be important in the pathogenesis of common diseases, such as obesity and type 2 diabetes mellitus.

  6. Differences in the interaction of acetylcholine receptor antibodies with receptor from normal, denervated and myasthenic human muscle.

    OpenAIRE

    Lefvert, A. K.

    1982-01-01

    The interaction of acetylcholine receptor antibodies with different kinds of human skeletal muscle receptor was investigated. The reaction of most receptor antibodies was strongest with receptor from a patient with myasthenia gravis and with receptor from denervated muscle. Results obtained with these receptors were well correlated. The binding of most receptor antibodies to receptor from functionally normal muscle was much weaker and also qualitatively different. In a few patients with moder...

  7. Receptor arrays optimized for natural odor statistics.

    Science.gov (United States)

    Zwicker, David; Murugan, Arvind; Brenner, Michael P

    2016-05-17

    Natural odors typically consist of many molecules at different concentrations. It is unclear how the numerous odorant molecules and their possible mixtures are discriminated by relatively few olfactory receptors. Using an information theoretic model, we show that a receptor array is optimal for this task if it achieves two possibly conflicting goals: (i) Each receptor should respond to half of all odors and (ii) the response of different receptors should be uncorrelated when averaged over odors presented with natural statistics. We use these design principles to predict statistics of the affinities between receptors and odorant molecules for a broad class of odor statistics. We also show that optimal receptor arrays can be tuned to either resolve concentrations well or distinguish mixtures reliably. Finally, we use our results to predict properties of experimentally measured receptor arrays. Our work can thus be used to better understand natural olfaction, and it also suggests ways to improve artificial sensor arrays.

  8. Targeting Nuclear Receptors with Marine Natural Products

    Directory of Open Access Journals (Sweden)

    Chunyan Yang

    2014-01-01

    Full Text Available Nuclear receptors (NRs are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators.

  9. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    Nutrients, biological waste-products, toxins, pathogens, and other ligands for endocytosis are typically captured by multidomain receptors with multiligand specificity. Upon internalization, the receptor-ligand complex segregates, followed by lysosomal degradation of the ligand and recycling...... of the receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect...

  10. Receptor arrays optimized for natural odor statistics

    CERN Document Server

    Zwicker, David; Brenner, Michael P

    2016-01-01

    Natural odors typically consist of many molecules at different concentrations. It is unclear how the numerous odorant molecules and their possible mixtures are discriminated by relatively few olfactory receptors. Using an information-theoretic model, we show that a receptor array is optimal for this task if it achieves two possibly conflicting goals: (i) each receptor should respond to half of all odors and (ii) the response of different receptors should be uncorrelated when averaged over odors presented with natural statistics. We use these design principles to predict statistics of the affinities between receptors and odorant molecules for a broad class of odor statistics. We also show that optimal receptor arrays can be tuned to either resolve concentrations well or distinguish mixtures reliably. Finally, we use our results to predict properties of experimentally measured receptor arrays. Our work can thus be used to better understand natural olfaction and it also suggests ways to improve artificial sensor...

  11. Glutamate Receptor Aptamers and ALS

    Science.gov (United States)

    2009-01-01

    proposed, including oxidative stress, excitotoxicity, mitochondrial dysfunction, etc., the cause(s) of the disease, including the pathogenesis of the...GluR6-Selective Aptamers for Potential Autism Therapy This project is to develop RNA aptamers against a GluR6 kainate receptor mutant thought to be...involved in autism . Role: PI Department of Defense (PI: Niu) 4/1/09-3/30/14 Advanced Tech./Therapeutic Develop. Grant Developing Biostable

  12. The vanilloid receptor and hypertension

    Institute of Scientific and Technical Information of China (English)

    Donna H WANG

    2005-01-01

    Mammalian transient receptor potential (TRP) channels consist of six related protein sub-families that are involved in a variety of pathophysiological function, and disease development. The TRPV1 channel, a member of the TRPV sub-family, is identified by expression cloning using the "hot" pepper-derived vanilloid compound capsaicin as a ligand. Therefore, TRPV1 is also referred as the vanilloid receptor (VR1) or the capsaicin receptor. VR1 is mainly expressed in a subpopulation of primary afferent neurons that project to cardiovascular and renal tissues.These capsaicin-sensitive primary afferent neurons are not only involved in the perception of somatic and visceral pain, but also have a "sensory-effector" function.Regarding the latter, these neurons release stored neuropeptides through a calcium-dependent mechanism via the binding of capsaicin to VR1. The most studied sensory neuropeptides are calcitonin gene-related peptide (CGRP) and substance P (SP), which are potent vasodilators and natriuretic/diuretic factors. Recent evidence using the model of neonatal degeneration of capsaicin-sensitive sensory nerves revealed novel mechanisms that underlie increased salt sensitivity and several experimental models of hypertension. These mechanisms include insufficient suppression of plasma renin activity and plasma aldosterone levels subsequent to salt loading, enhancement of sympathoexcitatory response in the face of a salt challenge, activation of the endothelin- 1 receptor, and impaired natriuretic response to salt loading in capsaicin-pretreated rats. These data indicate that sensory nerves counterbalance the prohypertensive effects of several neurohormonal systems to maintain normal blood pressure when challenged with salt loading. The therapeutic utilities of vanilloid compounds, endogenous agonists,and sensory neuropeptides are also discussed.

  13. Endomorphins interact with tachykinin receptors.

    Science.gov (United States)

    Kosson, Piotr; Bonney, Iwona; Carr, Daniel B; Lipkowski, Andrzej W

    2005-09-01

    Soon after the discovery of endomorphins several studies indicated differences between pharmacological effects of endomorphins and other MOR selective ligands, as well as differences between the effects of endomorphin I and endomorphin II. We now propose that these differences are the result of an additional non-opioid property of endomorphins, namely, their weak antagonist properties with respect to tachykinin NK1 and NK1 receptors.

  14. The Laminins and their Receptors

    OpenAIRE

    Ferletta, Maria

    2002-01-01

    Basement membranes are thin extracellular sheets that surround muscle, fat and peripheral nerve cells and underlay epithelial and endothelial cells. Laminins are one of the main protein families of these matrices. Integrins and dystroglycan are receptors for laminins, connecting cells to basement membranes. Each laminin consists of three different chains, (α, β, γ). Laminin-1 (α1β1γ1) was the first laminin to be found and is the most frequently studied. Despite this, it was unclear where its ...

  15. Nitrosamines as nicotinic receptor ligands

    OpenAIRE

    Schuller, Hildegard M

    2007-01-01

    Nitrosamines are carcinogens formed in the mammalian organism from amine precursors contained in food, beverages, cosmetics and drugs. The potent carcinogen, NNK, and the weaker carcinogen, NNN, are nitrosamines formed from nicotine. Metabolites of the nitrosamines react with DNA to form adducts responsible for genotoxic effects. We have identified NNK as a high affinity agonist for the alpha7 nicotinic acetylcholine receptor (α7nAChR) whereas NNN bound with high affinity to epibatidine-sensi...

  16. CB receptor ligands from plants.

    Science.gov (United States)

    Woelkart, Karin; Salo-Ahen, Outi M H; Bauer, Rudolf

    2008-01-01

    Advances in understanding the physiology and pharmacology of the endogenous cannabinoid system have potentiated the interest of cannabinoid receptors as potential therapeutic targets. Cannabinoids have been shown to modulate a variety of immune cell functions and have therapeutic implications on central nervous system (CNS) inflammation, chronic inflammatory conditions such as arthritis, and may be therapeutically useful in treating autoimmune conditions such as multiple sclerosis. Many of these drug effects occur through cannabinoid receptor signalling mechanisms and the modulation of cytokines and other gene products. Further, endocannabinoids have been found to have many physiological and patho-physiological functions, including mood alteration and analgesia, control of energy balance, gut motility, motor and co-ordination activities, as well as alleviation of neurological, psychiatric and eating disorders. Plants offer a wide range of chemical diversity and have been a growing domain in the search for effective cannabinoid ligands. Cannabis sativa L. with the known plant cannabinoid, Delta(9-)tetrahydrocannabinol (THC) and Echinacea species with the cannabinoid (CB) receptor-binding lipophilic alkamides are the best known herbal cannabimimetics. This review focuses on the state of the art in CB ligands from plants, as well their possible therapeutic and immunomodulatory effects.

  17. Autophagy selectivity through receptor clustering

    Science.gov (United States)

    Rutenberg, Andrew; Brown, Aidan

    Substrate selectivity in autophagy requires an all-or-none cellular response. We focus on peroxisomes, for which autophagy receptor proteins NBR1 and p62 are well characterized. Using computational models, we explore the hypothesis that physical clustering of autophagy receptor proteins on the peroxisome surface provides an appropriate all-or-none response. We find that larger peroxisomes nucleate NBR1 clusters first, and lose them due to competitive coarsening last, resulting in significant size-selectivity. We then consider a secondary hypothesis that p62 inhibits NBR1 cluster formation. We find that p62 inhibition enhances size-selectivity enough that, even if there is no change of the pexophagy rate, the volume of remaining peroxisomes can significantly decrease. We find that enhanced ubiquitin levels suppress size-selectivity, and that this effect is more pronounced for individual peroxisomes. Sufficient ubiquitin allows receptor clusters to form on even the smallest peroxisomes. We conclude that NBR1 cluster formation provides a viable physical mechanism for all-or-none substrate selectivity in pexophagy. We predict that cluster formation is associated with significant size-selectivity. Now at Simon Fraser University.

  18. [Anti-NMDA-receptor encephalitis].

    Science.gov (United States)

    Engen, Kristine; Agartz, Ingrid

    2016-06-01

    BACKGROUND In 2007 a clinical disease caused by autoantibodies directed against the N-methyl-D-aspartate (NMDA) receptor was described for the first time. Anti-NMDA-receptor encephalitis is a subacute, autoimmune neurological disorder with psychiatric manifestations. The disease is a form of limbic encephalitis and is often paraneoplastic. The condition is also treatable. In this review article we examine the development of the disease, clinical practice, diagnostics and treatment.MATERIAL AND METHOD The article is based on references retrieved from searches in PubMed, and a discretionary selection of articles from the authors' own literature archive.RESULTS The disease most frequently affects young women. It may initially be perceived as a psychiatric condition, as it usually presents in the form of delusions, hallucinations or mania. The diagnosis should be suspected in patients who later develop neurological symptoms such as various movement disorders, epileptic seizures and autonomic instability. Examination of serum or cerebrospinal fluid for NMDA receptor antibodies should be included in the assessment of patients with suspected encephalitis. MRI, EEG and assessment for tumours are important tools in diagnosing the condition and any underlying malignancy.INTERPRETATION If treatment is initiated early, the prognosis is good. Altogether 75 % of patients will fully recover or experience significant improvement. Apart from surgical resection of a possible tumour, the treatment consists of immunotherapy. Because of good possibilities for treatment, it is important that clinicians, particularly those in acute psychiatry, are aware of and alert to this condition.

  19. Presynaptic inhibition by kainate receptors converges mechanistically with presynaptic inhibition by adenosine and GABAB receptors.

    Science.gov (United States)

    Partovi, Dara; Frerking, Matthew

    2006-11-01

    Kainate receptors are widely reported to regulate the release of neurotransmitter in the CNS, but the mechanisms involved remain controversial. Previous studies have found that the kainate receptor agonist ATPA, which selectively activates Glu(K5)-containing kainate receptors, depresses glutamate release at Schaffer-collateral synapses in the hippocampus. In the present study, we provide pharmacological evidence that this depressant effect is mediated by Glu(K5)-containing heteromers, but is distinct from a similar depressant effect engaged by the kainate receptor agonist domoate. The depressant effect of ATPA is insensitive to antagonists for GABA(A), GABA(B), and adenosine receptors, and is also unaffected by lowering the release probability by reducing extracellular calcium. However, the effect of ATPA is partly occluded by prior activation of GABA(B) receptors and completely occluded by prior activation of adenosine receptors, suggesting a mechanistic convergence of heteromeric Glu(K5) kainate receptor signaling with GABA(B) receptors and adenosine receptors. The effects of domoate are partially occluded by both adenosine and GABA(B) receptor agonists, indicating at least a partial convergence of Glu(K5)-lacking kainate receptor signaling with these other pathways. The depressant effect of ATPA is not blocked by inhibition of serine/threonine protein kinases. These results suggest that ATPA and domoate inhibit glutamate release through mechanisms that converge with those of classical metabotropic receptor agonists, although they do so through different receptors.

  20. Receptor response in Venus's fly-trap.

    Science.gov (United States)

    Jacobson, S L

    1965-09-01

    The insect-trapping movement of the plant Dionaea muscipula (Venus's fly-trap) is mediated by the stimulation of mechanosensory hairs located on the surface of the trap. It is known that stimulation of the hairs is followed by action potentials which are propagated over the surface of the trap. It has been reported that action potentials always precede trap closure. The occurrence of non-propagated receptor potentials is reported here. Receptor potentials always precede the action potentials. The receptor potential appears to couple the mechanical stimulation step to the action potential step of the preying sequence. Receptor potentials elicited by mechanical stimulation of a sensory hair were measured by using the hair as an integral part of the current-measuring path. The tip of the hair was cut off exposing the medullary tissue; this provided a natural extension of the measuring electrode into the receptor region at the base of the hair. A measuring pipette electrode was slipped over the cut tip of the hair. Positive and negative receptor potentials were measured. Evidence is presented which supports the hypothesis that the positive and negative receptor potentials originate from independent sources. An analysis is made of (a) the relation of the parameters of mechanical stimuli to the magnitude of the receptor potential, and (b) the relation of the receptor potentials to the action potential. The hypothesis that the positive receptor potential is the generator of the action potential is consistent with these data.

  1. Constitutive receptor systems for drug discovery.

    Science.gov (United States)

    Chen, G; Jayawickreme, C; Way, J; Armour, S; Queen, K; Watson, C; Ignar, D; Chen, W J; Kenakin, T

    1999-12-01

    This paper discusses the use of constitutively active G-protein-coupled receptor systems for drug discovery. Specifically, the ternary complex model is used to define the two major theoretical advantages of constitutive receptor screening-namely, the ability to detect antagonists as well as agonists directly and the fact that constitutive systems are more sensitive to agonists. In experimental studies, transient transfection of Chinese hamster ovary cyclic AMP response element (CRE) luciferase reporter cells with cDNA for human parathyroid hormone receptor, glucagon receptor, and glucagon-like peptide (GLP-1) receptor showed cDNA concentration-dependent constitutive activity with parathyroid hormone (PTH-1) and glucagon. In contrast, no constitutive activity was observed for GLP-1 receptor, yet responses to GLP-1 indicated that receptor expression had taken place. In another functional system, Xenopus laevi melanophores transfected with cDNA for human calcitonin receptor showed constitutive activity. Nine ligands for the calcitonin receptor either increased or decreased constitutive activity in this assay. The sensitivity of the system to human calcitonin increased with increasing constitutive activity. These data indicate that, for those receptors which naturally produce constitutive activity, screening in this mode could be advantageous over other methods.

  2. Protein Connectivity in Chemotaxis Receptor Complexes.

    Directory of Open Access Journals (Sweden)

    Stephan Eismann

    2015-12-01

    Full Text Available The chemotaxis sensory system allows bacteria such as Escherichia coli to swim towards nutrients and away from repellents. The underlying pathway is remarkably sensitive in detecting chemical gradients over a wide range of ambient concentrations. Interactions among receptors, which are predominantly clustered at the cell poles, are crucial to this sensitivity. Although it has been suggested that the kinase CheA and the adapter protein CheW are integral for receptor connectivity, the exact coupling mechanism remains unclear. Here, we present a statistical-mechanics approach to model the receptor linkage mechanism itself, building on nanodisc and electron cryotomography experiments. Specifically, we investigate how the sensing behavior of mixed receptor clusters is affected by variations in the expression levels of CheA and CheW at a constant receptor density in the membrane. Our model compares favorably with dose-response curves from in vivo Förster resonance energy transfer (FRET measurements, demonstrating that the receptor-methylation level has only minor effects on receptor cooperativity. Importantly, our model provides an explanation for the non-intuitive conclusion that the receptor cooperativity decreases with increasing levels of CheA, a core signaling protein associated with the receptors, whereas the receptor cooperativity increases with increasing levels of CheW, a key adapter protein. Finally, we propose an evolutionary advantage as explanation for the recently suggested CheW-only linker structures.

  3. Characterization of astrocytic and neuronal benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bender, A.S.

    1988-01-01

    Primary cultures of astrocytes and neurons express benzodiazepine receptors. Neuronal benzodiazepine receptors were of high-affinity, K{sub D} values were 7.5-43 nM and the densities of receptors (B{sub max}) were 924-4131 fmol/mg protein. Astrocytes posses a high-affinity benzodiazepine receptor, K{sub D} values were 6.6-13 nM. The B{sub max} values were 6,033-12,000 fmol/mg protein. The pharmacological profile of the neuronal benzodiazepine receptor was that of the central-type benzodiazepine receptor, where clonazepam has a high-affinity and Ro 5-4864 (4{prime}-chlorodiazepam) has a low-affinity. Whereas astrocytic benzoidazepine receptor was characteristic of the so called peripheral-type benzodiazepine receptors, which shows a high-affinity towards Ro 5-4863, and a low-affinity towards clonazepam. The astrocytic benzodiazepine receptors was functionally correlated with voltage dependent calcium channels, since dihydropyridines and benzodiazepines interacted with ({sup 3}H) diazepam and ({sup 3}H) nitrendipine receptors with the same rank order of potency, showing a statistically significant correlation. No such correlation was observed in neurons.

  4. Lefty blocks a subset of TGFbeta signals by antagonizing EGF-CFC coreceptors.

    Directory of Open Access Journals (Sweden)

    Simon K Cheng

    2004-02-01

    Full Text Available Members of the EGF-CFC family play essential roles in embryonic development and have been implicated in tumorigenesis. The TGFbeta signals Nodal and Vg1/GDF1, but not Activin, require EGF-CFC coreceptors to activate Activin receptors. We report that the TGFbeta signaling antagonist Lefty also acts through an EGF-CFC-dependent mechanism. Lefty inhibits Nodal and Vg1 signaling, but not Activin signaling. Lefty genetically interacts with EGF-CFC proteins and competes with Nodal for binding to these coreceptors. Chimeras between Activin and Nodal or Vg1 identify a 14 amino acid region that confers independence from EGF-CFC coreceptors and resistance to Lefty. These results indicate that coreceptors are targets for both TGFbeta agonists and antagonists and suggest that subtle sequence variations in TGFbeta signals result in greater ligand diversity.

  5. Assembly of PRR-containing receptors on scaffolds: a model for imidazoline I(1)-receptor action.

    Science.gov (United States)

    Musgrave, I F; Dehle, F C; Piletz, J

    2003-12-01

    IRAS, a putative clone of the I(1)-imidazoline receptor, possesses a proline-rich region (PRR) motif, which might interact with SH3 regions on tyrosine kinases, and an integrin-binding motif. Receptors with a PRR motif can generally assemble onto multi-element signaling complexes (eg., the beta(3)-receptor on the EGF receptor) and thereby modulate signal transduction. Integrins serve as scaffolds for multi-element signaling complexes, similar to that assembled with the EGF receptor. It is therefore possible that IRAS signals through a complex with other receptors.

  6. Subtype selective kainic acid receptor agonists

    DEFF Research Database (Denmark)

    Bunch, Lennart; Krogsgaard-Larsen, Povl

    2009-01-01

    (S)-Glutamic acid (Glu) is the major excitatory neurotransmitter in the mammalian central nervous system, activating the plethora of glutamate receptors (GluRs). In broad lines, the GluRs are divided into two major classes: the ionotropic Glu receptors (iGluRs) and the metabotropic Glu receptors (m......GluRs). Within the iGluRs, five subtypes (KA1, KA2, iGluR5-7) show high affinity and express full agonist activity upon binding of the naturally occurring amino acid kainic acid (KA). Thus these receptors have been named the KA receptors. This review describes all-to our knowledge-published KA receptor agonists...

  7. Mast Cell and Immune Inhibitory Receptors

    Institute of Scientific and Technical Information of China (English)

    LixinLi; ZhengbinYao

    2004-01-01

    Modulation by balancing activating and inhibitory receptors constitutes an important mechanism for regulating immune responses. Cells that are activated following ligation of receptors bearing immunoreceptor tyrosine-based activation motifs (ITAMs) can be negatively regulated by other receptors bearing immunoreceptor tyrosine-based inhibition motifs (ITIMs). Human mast cells (MCs) are the major effector cells of type I hypersensitivity and important participants in a number of disease processes. Antigen-mediated aggregation of IgE bound to its high-affinity receptor on MCs initiates a complex series of biochemical events leading to MC activation. With great detailed description and analysis of several inhibitory receptors on human MCs, a central paradigm of negative regulation of human MC activation by these receptors has emerged. Cellular & Molecular Immunology. 2004;1(6):408-415.

  8. The anatomy of mammalian sweet taste receptors.

    Science.gov (United States)

    Chéron, Jean-Baptiste; Golebiowski, Jérôme; Antonczak, Serge; Fiorucci, Sébastien

    2017-02-01

    All sweet-tasting compounds are detected by a single G-protein coupled receptor (GPCR), the heterodimer T1R2-T1R3, for which no experimental structure is available. The sweet taste receptor is a class C GPCR, and the recently published crystallographic structures of metabotropic glutamate receptor (mGluR) 1 and 5 provide a significant step forward for understanding structure-function relationships within this family. In this article, we recapitulate more than 600 single point site-directed mutations and available structural data to obtain a critical alignment of the sweet taste receptor sequences with respect to other class C GPCRs. Using this alignment, a homology 3D-model of the human sweet taste receptor is built and analyzed to dissect out the role of key residues involved in ligand binding and those responsible for receptor activation. Proteins 2017; 85:332-341. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. P2X receptors in epithelia

    DEFF Research Database (Denmark)

    Leipziger, Jens Georg

    2015-01-01

    pathways that inhibit epithelial absorption are currently not well understood. Epithelial P2X7 receptors show pronounced up-regulation during varies diseased states highlighting a role of purinergic signaling in epithelial pathophysiology. Importantly, functional effects of epithelial P2X receptors cover......P2X receptors are ubiquitously expressed in all epithelial tissues but their functional roles are less well studied. Here we review the current state of knowledge by focusing on functional effects of P2X receptor in secretory and in absorptive tissues. In glandular tissue like the parotid gland...... basolateral P2X receptors stimulate ion secretion via an increase of [Ca2+]i. In absorptive epithelia like the renal tubule P2X receptor stimulation mediates the inhibition of NaCl, Mg2+ and water transport in the thick ascending limb and the distal convoluted tubule, respectively. The underlying signaling...

  10. Nitrosamines as nicotinic receptor ligands.

    Science.gov (United States)

    Schuller, Hildegard M

    2007-05-30

    Nitrosamines are carcinogens formed in the mammalian organism from amine precursors contained in food, beverages, cosmetics and drugs. The potent carcinogen, NNK, and the weaker carcinogen, NNN, are nitrosamines formed from nicotine. Metabolites of the nitrosamines react with DNA to form adducts responsible for genotoxic effects. We have identified NNK as a high affinity agonist for the alpha7 nicotinic acetylcholine receptor (alpha7nAChR) whereas NNN bound with high affinity to epibatidine-sensitive nAChRs. Diethylnitrosamine (DEN) bound to both receptors but with lower affinity. High levels of the alpha7nAChR were expressed in human small cell lung cancer (SCLC) cell lines and in hamster pulmonary neuroendocrine cells (PNECs), which serve as a model for the cell of origin of human SCLC. Exposure of SCLC or PNECs to NNK or nicotine increased expression of the alpha7nAChR and caused influx of Ca(2+), activation of PKC, Raf-1, ERK1/2, and c-myc, resulting in the stimulation of cell proliferation. Signaling via the alpha7nAChR was enhanced when cells were maintained in an environment of 10-15% CO(2) similar to that in the diseased lung. Hamsters with hyperoxia-induced pulmonary fibrosis developed neuroendocrine lung carcinomas similar to human SCLC when treated with NNK, DEN, or nicotine. The development of the NNK-induced tumors was prevented by green tea or theophylline. The beta-adrenergic receptor agonist, isoproterenol or theophylline blocked NNK-induced cell proliferation in vitro. NNK and nicotine-induced hyperactivity of the alpha7nAChR/RAF/ERK1/2 pathway thus appears to play a crucial role in the development of SCLC in smokers and could be targeted for cancer prevention.

  11. Angiotensin II receptors in the gonads

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, G.; Millan, M.A.; Harwood, J.P.

    1989-05-01

    The presence of components of the renin-angiotensin system in ovaries and testes suggests that angiotensin II (AII) is involved in gonadal function, and thus we sought to characterize receptors for AII in rat and primate gonads. In the testes, autoradiographic studies showed receptors in the interstitium in all species. In rat interstitial cells fractionated by Percoll gradient, AII receptors coincided with hCG receptors indicating that AII receptors are located on the Leydig cells. In Leydig cells and membranes from rat and rhesus monkey prepuberal testes, AII receptors were specific for AII analogues and of high affinity (Kd=nM). During development, AII receptor content in rat testes decreases with age parallel to a fall in the ratio of interstitial to tubular tissue. In the ovary, the distribution of AII receptors was dependent on the stage of development, being high in the germinal epithelium and stromal tissue between five and 15 days, and becoming localized in secondary follicles in 20-and 40-day-old rats. No binding was found in primordial or primary follicles. In rhesus monkey ovary, AII receptors were higher in stromal tissue and lower in granulosa and luteal cells of the follicles. Characterization of the binding in rat and monkey ovarian membranes showed a single class of sites with a Kd in the nmol/L range and specificity similar to that of the adrenal glomerulosa and testicular AII receptors. Receptors for AII were also present in membrane fractions from PMSG/hCG primed rat ovaries. Infusion of AII (25 ng/min) or captopril (1.4 micrograms/min) during the PMSG/hCG induction period had no effect on ovarian weight or AII receptor concentration in the ovaries.

  12. Complex pharmacology of free fatty acid receptors

    OpenAIRE

    Milligan, Graeme; Shimpukade, Bharat; Ulven, Trond; Hudson, Brian D.

    2017-01-01

    G protein-coupled receptors (GPCRs) are historically the most successful family of drug targets. In recent times it has become clear that the pharmacology of these receptors is far more complex than previously imagined. Understanding of the pharmacological regulation of GPCRs now extends beyond simple competitive agonism or antagonism by ligands interacting with the orthosteric binding site of the receptor to incorporate concepts of allosteric agonism, allosteric modulation, signaling bias, c...

  13. Muscarinic Receptor Agonists and Antagonists

    Directory of Open Access Journals (Sweden)

    David R. Kelly

    2001-02-01

    Full Text Available A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes. Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.

  14. Emerging GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2011-01-01

    Introduction: Recently, glucagon-like peptide-1 receptor (GLP-1R) agonists have become available for the treatment of type 2 diabetes. These agents exploit the physiological effects of GLP-1, which is able to address several of the pathophysiological features of type 2 diabetes. GLP-1R agonists...... presently available are administered once or twice daily, but several once-weekly GLP-1R agonists are in late clinical development. Areas covered: The present review aims to give an overview of the clinical data on the currently available GLP-1R agonists used for treatment of type 2 diabetes, exenatide...

  15. New transmembrane AMPA receptor regulatory protein isoform, gamma-7, differentially regulates AMPA receptors

    National Research Council Canada - National Science Library

    Kato, Akihiko S; Zhou, Wei; Milstein, Aaron D; Knierman, Mike D; Siuda, Edward R; Dotzlaf, Joe E; Yu, Hong; Hale, John E; Nisenbaum, Eric S; Nicoll, Roger A; Bredt, David S

    2007-01-01

    AMPA-type glutamate receptors (GluRs) mediate most excitatory signaling in the brain and are composed of GluR principal subunits and transmembrane AMPA receptor regulatory protein (TARP) auxiliary subunits...

  16. The angiotensin Ⅱ type 1 receptor and receptor-associated proteins

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mechanisms of regulation, activation and signal transduction of the angiotensin Ⅱ(Ang Ⅱ) type 1 (AT1) receptor have been studied extensively in the decade after its cloning. The AT1receptor is a major component of the renin-angiotensin system (RAS). It mediates the classical biological actions of Ang Ⅱ. Among the structures required for regulation and activation of the receptor, its carboxylterminal region plays crucial roles in receptor internalization, desensitization and phosphorylation. The mechanisms involved in heterotrimeric G-protein coupling to the receptor, activation of the downstreamsignaling pathway by G proteins and the Ang Ⅱ signal transduction pathways leading to specific cellularresponses are discussed. In addition, recent work on the identification and characterization of novel proteinsassociated with carboxyl-terminus of the AT1 receptor is presented. These novel proteins will advance ourunderstanding of how the receptor is internalized and recycled as they provide molecular mechanisms for the activation and regulation of G-protein-coupled receptors.

  17. ABA Receptors: Past, Present and Future

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianjun [Harvard University; Yang, Xiaohan [ORNL; Weston, David [ORNL; Chen, Jay [ORNL

    2011-01-01

    Abscisic acid (ABA) is the key plant stress hormone. Consistent with the earlier studies in support of the presence of both membrane- and cytoplasm-localized ABA receptors, recent studies have identified multiple ABA receptors located in various subcellular locations. These include a chloroplast envelope-localized receptor (the H subunit of Chloroplast Mg2+-chelatase/ABA Receptor), two plasma membrane-localized receptors (G-protein Coupled Receptor 2 and GPCR-type G proteins), and one cytosol/nucleus-localized Pyrabactin Resistant (PYR)/PYR-Like (PYL)/Regulatory Component of ABA Receptor 1 (RCAR). Although the downstream molecular events for most of the identified ABA receptors are currently unknown, one of them, PYR/PYL/RACR was found to directly bind and regulate the activity of a long-known central regulator of ABA signaling, the A-group protein phosphatase 2C (PP2C). Together with the Sucrose Non-fermentation Kinase Subfamily 2 (SnRK2s) protein kinases, a central signaling complex (ABA-PYR-PP2Cs-SnRK2s) that is responsible for ABA signal perception and transduction is supported by abundant genetic, physiological, biochemical and structural evidence. The identification of multiple ABA receptors has advanced our understanding of ABA signal perception and transduction while adding an extra layer of complexity.

  18. Challenges in imaging cell surface receptor clusters

    Science.gov (United States)

    Medda, Rebecca; Giske, Arnold; Cavalcanti-Adam, Elisabetta Ada

    2016-01-01

    Super-resolution microscopy offers unique tools for visualizing and resolving cellular structures at the molecular level. STED microscopy is a purely optical method where neither complex sample preparation nor mathematical post-processing is required. Here we present the use of STED microscopy for imaging receptor cluster composition. We use two-color STED to further determine the distribution of two different receptor subunits of the family of receptor serine/threonine kinases in the presence or absence of their ligands. The implications of receptor clustering on the downstream signaling are discussed, and future challenges are also presented.

  19. Neuropeptide Receptor Transcriptome Reveals Unidentified Neuroendocrine Pathways

    Science.gov (United States)

    Yamanaka, Naoki; Yamamoto, Sachie; Žitňan, Dušan; Watanabe, Ken; Kawada, Tsuyoshi; Satake, Honoo; Kaneko, Yu; Hiruma, Kiyoshi; Tanaka, Yoshiaki; Shinoda, Tetsuro; Kataoka, Hiroshi

    2008-01-01

    Neuropeptides are an important class of molecules involved in diverse aspects of metazoan development and homeostasis. Insects are ideal model systems to investigate neuropeptide functions, and the major focus of insect neuropeptide research in the last decade has been on the identification of their receptors. Despite these vigorous efforts, receptors for some key neuropeptides in insect development such as prothoracicotropic hormone, eclosion hormone and allatotropin (AT), remain undefined. In this paper, we report the comprehensive cloning of neuropeptide G protein-coupled receptors from the silkworm, Bombyx mori, and systematic analyses of their expression. Based on the expression patterns of orphan receptors, we identified the long-sought receptor for AT, which is thought to stimulate juvenile hormone biosynthesis in the corpora allata (CA). Surprisingly, however, the AT receptor was not highly expressed in the CA, but instead was predominantly transcribed in the corpora cardiaca (CC), an organ adjacent to the CA. Indeed, by using a reverse-physiological approach, we purified and characterized novel allatoregulatory peptides produced in AT receptor-expressing CC cells, which may indirectly mediate AT activity on the CA. All of the above findings confirm the effectiveness of a systematic analysis of the receptor transcriptome, not only in characterizing orphan receptors, but also in identifying novel players and hidden mechanisms in important biological processes. This work illustrates how using a combinatorial approach employing bioinformatic, molecular, biochemical and physiological methods can help solve recalcitrant problems in neuropeptide research. PMID:18725956

  20. Neuropeptide receptor transcriptome reveals unidentified neuroendocrine pathways.

    Directory of Open Access Journals (Sweden)

    Naoki Yamanaka

    Full Text Available Neuropeptides are an important class of molecules involved in diverse aspects of metazoan development and homeostasis. Insects are ideal model systems to investigate neuropeptide functions, and the major focus of insect neuropeptide research in the last decade has been on the identification of their receptors. Despite these vigorous efforts, receptors for some key neuropeptides in insect development such as prothoracicotropic hormone, eclosion hormone and allatotropin (AT, remain undefined. In this paper, we report the comprehensive cloning of neuropeptide G protein-coupled receptors from the silkworm, Bombyx mori, and systematic analyses of their expression. Based on the expression patterns of orphan receptors, we identified the long-sought receptor for AT, which is thought to stimulate juvenile hormone biosynthesis in the corpora allata (CA. Surprisingly, however, the AT receptor was not highly expressed in the CA, but instead was predominantly transcribed in the corpora cardiaca (CC, an organ adjacent to the CA. Indeed, by using a reverse-physiological approach, we purified and characterized novel allatoregulatory peptides produced in AT receptor-expressing CC cells, which may indirectly mediate AT activity on the CA. All of the above findings confirm the effectiveness of a systematic analysis of the receptor transcriptome, not only in characterizing orphan receptors, but also in identifying novel players and hidden mechanisms in important biological processes. This work illustrates how using a combinatorial approach employing bioinformatic, molecular, biochemical and physiological methods can help solve recalcitrant problems in neuropeptide research.

  1. Abscisic Acid Receptors: Past, Present and Future

    Institute of Scientific and Technical Information of China (English)

    Jianjun Guo; Xiaohan Yang; David J. Weston; Jin-Gui Chen

    2011-01-01

    Abscisic acid (ABA) is the key plant stress hormone. Consistent with the earlier studies in support of the presence of both membrane- and cytoplasm-localized ABA receptors, recent studies have identified multiple ABA receptors located in various subcellular locations. These include a chloroplast envelope-localized receptor (the H subunit of Chloroplast Mg2+-chelatase/ABA Receptor), two plasma membrane-localized receptors (G-protein Coupled Receptor 2 and GPCR-type G proteins),and one cytosol/nucleus-localized Pyrabactin Resistant (PYR)/PYR-Like (PYL)/Regulatory Component of ABA Receptor 1 (RCAR). Although the downstream molecular events for most of the identified ABA receptors are currently unknown, one of them, PYR/PYL/RCAR was found to directly bind and regulate the activity of a long-known central regulator of ABA signaling, the A-group protein phosphatase 2C (PP2C). Together with the Sucrose Non-fermentation Kinase Subfamily 2 (SnRK2s) protein kinases, a central signaling complex (ABA-PYR-PP2Cs-SnRK2s) that is responsible for ABA signal perception and transduction is supported by abundant genetic, physiological, biochemical and structural evidence. The identification of multiple ABA receptors has advanced our understanding of ABA signal perception and transduction while adding an extra layer of complexity.

  2. 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...

  3. Identification and mechanism of ABA receptor antagonism

    KAUST Repository

    Melcher, Karsten

    2010-08-22

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands. © 2010 Nature America, Inc. All rights reserved.

  4. Regulation of Estrogen Receptor Nuclear Export by Ligand-Induced and p38-Mediated Receptor Phosphorylation

    OpenAIRE

    Lee, Heehyoung; Bai, Wenlong

    2002-01-01

    Estrogen receptors are phosphoproteins which can be activated by ligands, kinase activators, or phosphatase inhibitors. Our previous study showed that p38 mitogen-activated protein kinase was involved in estrogen receptor activation by estrogens and MEKK1. Here, we report estrogen receptor-dependent p38 activation by estrogens in endometrial adenocarcinoma cells and in vitro and in vivo phosphorylation of the estrogen receptor α mediated through p38. The phosphorylation site was identified as...

  5. Studies on mu and delta opioid receptor selectivity utilizing chimeric and site-mutagenized receptors.

    Science.gov (United States)

    Wang, W W; Shahrestanifar, M; Jin, J; Howells, R D

    1995-01-01

    Opioid receptors are members of the guanine nucleotide binding protein (G protein)-coupled receptor family. Three types of opioid receptors have been cloned and characterized and are referred to as the delta, kappa and mu types. Analysis of receptor chimeras and site-directed mutant receptors has provided a great deal of information about functionally important amino acid side chains that constitute the ligand-binding domains and G-protein-coupling domains of G-protein-coupled receptors. We have constructed delta/mu opioid receptor chimeras that were express in human embryonic kidney 293 cells in order to define receptor domains that are responsible for receptor type selectivity. All chimeric receptors and wild-type delta and mu opioid receptors displayed high-affinity binding of etorphine (an agonist), naloxone (an antagonist), and bremazocine (a mixed agonist/antagonist). In contrast, chimeras that lacked the putative first extracellular loop of the mu receptor did not bind the mu-selective peptide [D-Ala2,MePhe4,Gly5-ol]enkephalin (DAMGO). Chimeras that lacked the putative third extracellular loop of the delta receptor did not bind the delta-selective peptide, [D-Ser2,D-Leu5]enkephalin-Thr (DSLET). Point mutations in the putative third extracellular loop of the wild-type delta receptor that converted vicinal arginine residues to glutamine abolished DSLET binding while not affecting bremazocine, etorphine, and naltrindole binding. We conclude that amino acids in the putative first extracellular loop of the mu receptor are critical for high-affinity DAMGO binding and that arginine residues in the putative third extracellular loop of the delta receptor are important for high-affinity DSLET binding. Images Fig. 3 PMID:8618916

  6. Epac2: a sulfonylurea receptor?

    Science.gov (United States)

    Rehmann, Holger

    2012-02-01

    Sulfonylureas are widely used oral drugs in the treatment of diabetes mellitus. They function by the inhibition of ATP-sensitive K+ channels in pancreatic β-cells, which are thus considered the 'classical' sulfonylurea receptor. Next to the ATP-sensitive K+ channels, additional sulfonylurea-interacting proteins were identified, which might contribute to the physiological effects of this drug family. Most recently, Epac2 (exchange protein directly activated by cAMP 2) was added to the list of sulfonylurea receptors. However, this finding caused controversy in the literature. The critical discussion of the present paper comes to the conclusion that sulfonylureas are not able to activate Epac2 directly and are unlikely to bind to Epac2. Increased blood glucose levels after food intake result in the secretion of insulin from pancreatic β-cells. Glucose levels are detected 'indirectly' by β-cells: owing to increased glycolysis rates, the ratio of cellular ATP/ADP increases and causes the closure of ATP-sensitive K+ channels. In consequence, cells depolarize and voltage-dependent Ca2+ channels open to cause an increase in the cellular Ca2+ concentration. Finally, Ca2+ induces the fusion of insulin-containing granules with the plasma membrane. Sulfonylureas, such as tolbutamide, glibenclamide or acetohexamide, form a class of orally applicable drugs used in the treatment of non-insulin-dependent diabetes mellitus.

  7. Prorenin receptor in kidney development.

    Science.gov (United States)

    Yosypiv, Ihor V

    2017-03-01

    Prorenin receptor (PRR), a receptor for renin and prorenin and an accessory subunit of the vacuolar proton pump H(+)-ATPase, is expressed in the developing kidney. Global loss of PRR is lethal in mice, and PRR mutations are associated with a high blood pressure, left ventricular hypertrophy and X-linked mental retardation in humans. With the advent of modern gene targeting techniques, including conditional knockout approaches, several recent studies have demonstrated critical roles for the PRR in several lineages of the developing kidney. PRR signaling has been shown to be essential for branching morphogenesis of the ureteric bud (UB), nephron progenitor survival and nephrogenesis. PRR regulates these developmental events through interactions with other transcription and growth factors. Several targeted PRR knockout animal models have structural defects mimicking congenital anomalies of the kidney and urinary tract observed in humans. The aim of this review, is to highlight new insights into the cellular and molecular mechanisms by which PRR may regulate UB branching, terminal differentiation and function of UB-derived collecting ducts, nephron progenitor maintenance, progression of nephrogenesis and normal structural kidney development and function.

  8. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  9. Androgen receptor drives cellular senescence.

    Directory of Open Access Journals (Sweden)

    Yelena Mirochnik

    Full Text Available The accepted androgen receptor (AR role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor.

  10. Receptor oligomerization in family B1 of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Roed, Sarah Norklit; Ørgaard, Anne; Jørgensen, Rasmus

    2012-01-01

    , the glucagon receptor, and the receptors for parathyroid hormone (PTHR1 and PTHR2). The dysregulation of several family B1 receptors is involved in diseases, such as diabetes, chronic inflammation, and osteoporosis which underlines the pathophysiological importance of this GPCR subfamily. In spite of this...

  11. The G protein-coupled receptor, class C, group 6, subtype A (GPRC6A) receptor

    DEFF Research Database (Denmark)

    Clemmensen, C; Smajilovic, S; Wellendorph, P;

    2014-01-01

    GPRC6A (G protein-coupled receptor, class C, group 6, subtype A) is a class C G protein-coupled receptor, that has been cloned from human, mouse and rat. Several groups have shown that the receptor is activated by a range of basic and small aliphatic L-α-amino acids of which L-arginine, L...

  12. The role of the CGRP-receptor component protein (RCP) in adrenomedullin receptor signal transduction.

    Science.gov (United States)

    Prado, M A; Evans-Bain, B; Oliver, K R; Dickerson, I M

    2001-11-01

    G protein-coupled receptors are usually thought to act as monomer receptors that bind ligand and then interact with G proteins to initiate signal transduction. In this study we report an intracellular peripheral membrane protein named the calcitonin gene-related peptide (CGRP)-receptor component protein (RCP) required for signal transduction at the G protein-coupled receptor for adrenomedullin. Cell lines were made that expressed an antisense construct of the RCP cDNA, and in these cells diminished RCP expression correlated with loss of adrenomedullin signal transduction. In contrast, loss of RCP did not diminish receptor density or affinity, therefore RCP does not appear to act as a chaperone protein. Instead, RCP represents a novel class of protein required to couple the adrenomedullin receptor to the cellular signal transduction pathway. A candidate adrenomedullin receptor named the calcitonin receptor-like receptor (CRLR) has been described, which forms high affinity adrenomedullin receptors when co-expressed with the accessory protein receptor-activity modifying protein 2 (RAMP2). RCP co-immunoprecipitated with CRLR and RAMP2, indicating that a functional adrenomedullin receptor is composed of at least three proteins: the ligand binding protein (CRLR), an accessory protein (RAMP2), and a coupling protein for signal transduction (RCP).

  13. A novel fluorescent receptor assay : Based upon receptors embedded in labeled liposomes

    NARCIS (Netherlands)

    Viel, Gerhard Theodoor

    1999-01-01

    Receptor proteins play an essential role in life. All organisms, from bacteria to plants, animals and human beings use receptors for their response to (external) signals. By definition, a receptor is a (macro) molecule which is able to recognize a distinct chemical entity (e.g. a hormone or neurotra

  14. A novel fluorescent receptor assay : based upon receptors embedded in labeled liposomes

    NARCIS (Netherlands)

    Viel, Gerhard Theodoor

    1999-01-01

    Receptor proteins play an essential role in life. All organisms, from bacteria to plants, animals and human beings use receptors for their response to (external) signals. By definition, a receptor is a (macro) molecule which is able to recognize a distinct chemical entity (e.g. a hormone or neurotra

  15. Microarray-based determination of estrogen receptor, progesterone receptor, and HER2 receptor status in breast cancer

    NARCIS (Netherlands)

    P. Roepman; H.M. Horlings; O. Krijgsman; M. Kok; J.M. Bueno-de-Mesquita; R. Bender; S.C. Linn; A.M. Glas; M.J. van de Vijver

    2009-01-01

    Purpose: The level of estrogen receptor (ER), progesterone receptor (PR), and HER2 aids in the determination of prognosis and treatment of breast cancer. Immunohistochemistry is currently the predominant method for assessment, but differences in methods and interpretation can substantially affect th

  16. Group I Metabotropic Glutamate Receptor Interacting Proteins: Fine-Tuning Receptor Functions in Health and Disease.

    Science.gov (United States)

    Kalinowska, Magdalena; Francesconi, Anna

    2016-01-01

    Group I metabotropic glutamate receptors mediate slow excitatory neurotransmission in the central nervous system and are critical to activity-dependent synaptic plasticity, a cellular substrate of learning and memory. Dysregulated receptor signaling is implicated in neuropsychiatric conditions ranging from neurodevelopmental to neurodegenerative disorders. Importantly, group I metabotropic glutamate receptor signaling functions can be modulated by interacting proteins that mediate receptor trafficking, expression and coupling efficiency to signaling effectors. These interactions afford cell- or pathway-specific modulation to fine-tune receptor function, thus representing a potential target for pharmacological interventions in pathological conditions.

  17. Identifying the receptor subtype selectivity of retinoid X and retinoic acid receptors via quantum mechanics.

    Science.gov (United States)

    Tsuji, Motonori; Shudo, Koichi; Kagechika, Hiroyuki

    2017-03-01

    Understanding and identifying the receptor subtype selectivity of a ligand is an important issue in the field of drug discovery. Using a combination of classical molecular mechanics and quantum mechanical calculations, this report assesses the receptor subtype selectivity for the human retinoid X receptor (hRXR) and retinoic acid receptor (hRAR) ligand-binding domains (LBDs) complexed with retinoid ligands. The calculated energies show good correlation with the experimentally reported binding affinities. The technique proposed here is a promising method as it reveals the origin of the receptor subtype selectivity of selective ligands.

  18. Down regulation of epidermal growth factor receptors: direct demonstration of receptor degradation in human fibroblasts

    OpenAIRE

    1984-01-01

    The metabolism of the receptor for epidermal growth factor (EGF) has been measured by labeling the receptor in vivo with radioactive amino acid precursors and then determining, by immunoprecipitation with specific anti-EGF receptor antisera, the rate of degradation of the receptor when the cells are placed in a nonradioactive medium. In human fibroblasts the rate of EGF receptor degradation (t1/2 = 10.1 h) was faster than the rate of degradation of total cell protein. When EGF was added to th...

  19. Transitional cell carcinoma express vitamin D receptors

    DEFF Research Database (Denmark)

    Hermann, G G; Andersen, C B

    1997-01-01

    .05). Similarly, also tumor grade appeared to be related to the number of cells expressing the receptor. Normal urothlium also expressed VDR but only with low intensity. Our study shows that TCC cells possess the VDR receptor which may make them capable to respond to stimulation with vitamin D, but functional...

  20. METHODOLOGICAL ASPECTS OF QUANTITATIVE RECEPTOR ASSAYS

    NARCIS (Netherlands)

    SMISTEROVA, J; ENSING, K; DEZEEUW, RA

    1994-01-01

    Receptor assays occupy a particular position in the methods used in bioanalysis, as they do not exploit the physico-chemical properties of the analyte. These assays make use of the property of the analyte to bind to the specific binding site (receptor) and to competitively replace a labelled ligand

  1. Transient receptor potential channels in essential hypertension

    DEFF Research Database (Denmark)

    Liu, Daoyan; Scholze, Alexandra; Zhu, Zhiming

    2006-01-01

    The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated.......The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated....

  2. [Olfactory esthesioneuroblastoma: scintigraphic expression of somatostatin receptors].

    Science.gov (United States)

    García Vicente, A; García Del Castillo, E; Soriano Castrejón, A; Alonso Farto, J

    1999-10-01

    Esthesioneuroblastoma is an uncommon tumor originating in the upper nasal cavity and constitutes 3% of all intranasal neoplasms. Few references exist about the expression of somatostatin receptors in these tumors. Our case demonstrates a good correlation between the somatostatin receptor scintigraphy and magnetic resonance imaging.

  3. Opioid receptor trafficking and interaction in nociceptors

    Science.gov (United States)

    Zhang, X; Bao, L; Li, S

    2015-01-01

    Opiate analgesics such as morphine are often used for pain therapy. However, antinociceptive tolerance and dependence may develop with long-term use of these drugs. It was found that μ-opioid receptors can interact with δ-opioid receptors, and morphine antinociceptive tolerance can be reduced by blocking δ-opioid receptors. Recent studies have shown that μ- and δ-opioid receptors are co-expressed in a considerable number of small neurons in the dorsal root ganglion. The interaction of μ-opioid receptors with δ-opioid receptors in the nociceptive afferents is facilitated by the stimulus-induced cell-surface expression of δ-opioid receptors, and contributes to morphine tolerance. Further analysis of the molecular, cellular and neural circuit mechanisms that regulate the trafficking and interaction of opioid receptors and related signalling molecules in the pain pathway would help to elucidate the mechanism of opiate analgesia and improve pain therapy. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2 PMID:24611685

  4. Evidence of paired M2 muscarinic receptors

    Energy Technology Data Exchange (ETDEWEB)

    Potter, L.T.; Ballesteros, L.A.; Bichajian, L.H.; Ferrendelli, C.A.; Fisher, A.; Hanchett, H.E.; Zhang, R. (Univ. of Miami School of Medicine, FL (USA))

    1991-02-01

    Binding assays involving various antagonists, including N-(3H) methylscopolamine, (3H)quinuclidinyl benzilate, AFDX-116, pirenzepine, and propylbenzilylcholine mustard, disclosed only a single population of M2 muscarinic receptors in membranes from the rat brainstem (medulla, pons, and colliculi). However, competition curves between N-(3H)methylscopolamine and various agonists, including oxotremorine, cis-dioxolane, and acetylethylcholine mustard, showed approximately equal numbers of guanine nucleotide-sensitive high affinity (H) sites and guanine nucleotide-insensitive low affinity (L) sites. This 50% H phenomenon persisted in different buffers, at different temperatures, after the number of receptors was halved (and, thus, the remaining receptor to guanine nucleotide-binding protein ratio was doubled), after membrane solubilization with digitonin, and when rabbit cardiac membranes were used instead of rat brainstem membranes. Preferential occupation of H sites with acetylethylcholine mustard, and of L sites with quinuclidinyl benzilate or either mustard, yielded residual free receptor populations showing predominantly L and H sites, respectively. Low concentrations of (3H)-oxotremorine-M labeled only H sites, and the Bmax for these sites was 49% of the Bmax found with (3H)quinuclidinyl benzilate plus guanine nucleotide. These and other results are most consistent with the idea that H and L receptor sites exist on separate but dimeric receptor molecules and with the hypothesis that only the H receptors cycle between high and low affinity, depending upon interactions between this receptor molecule and a guanine nucleotide-binding protein.

  5. Structural Studies of Nicotinic Acetylcholine Receptors

    DEFF Research Database (Denmark)

    Shahsavar, Azadeh; Gajhede, Michael; Kastrup, Jette

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) are members of the pentameric ligand-gated ion channel superfamily that play important roles in control of neurotransmitter release in the central and peripheral nervous system. These receptors are important therapeutic targets for development of drugs...

  6. Docking to flexible nicotinic acetylcholine receptors

    DEFF Research Database (Denmark)

    Sander, Tommy; Bruun, Anne T; Balle, Thomas

    2010-01-01

    Computational docking to nicotinic acetylcholine receptors (nAChRs) and other members of the Cys-loop receptor family is complicated by the flexibility of the so-called C-loop. As observed in the large number of published crystal structures of the acetylcholine binding protein (AChBP), a structural...

  7. Enantioselective Transport by a Steroidal Guanidinium Receptor

    NARCIS (Netherlands)

    Baragaña, Beatriz; Blackburn, Adrian G.; Breccia, Perla; Davis, Anthony P.; Mendoza, Javier de; Padrón-Carrillo, José M.; Prados, Pilar; Riedner, Jens; Vries, Johannes G. de

    2002-01-01

    The cationic steroidal receptors 9 and 11 have been synthesized from cholic acid 3. Receptor 9 extracts N-acetyl-α-amino acids from aqueous media into chloroform with enantioselectivities (L:D) of 7-10:1. The lipophilic variant 11 has been employed for the enantioselective transport of N-acetylpheny

  8. Characterization of the lymphocyte substance P receptor

    Energy Technology Data Exchange (ETDEWEB)

    McGillis, J.P.; Organist, M.L.; Payan, D.G.

    1986-03-01

    Recent studies have provided evidence that tissues of the immune and reticuloendothelial systems are influenced by various hormones and neuropeptides. While the interrelationship between these peptides and the immune system, and the physiological relevance of their effects is not clear, a variety of highly specific, receptor-mediated effects has been demonstrated. One neuropeptide for which immunomodulatory effects have been identified is substance P (SP). SP acts as a potent T-cell mitogen, and enhances the mitogenic effects of PHA. Radioreceptor and FACS binding studies suggest that the SP receptor is present on a discrete population of T-cells and has a Kd of 0.87 nM and a density of 24,000. Studies have been initiated to biochemically characterize the lymphocyte SP receptor on IM-9 lymphoblasts. (/sup 125/I)-labeled SP was covalently crosslinked to the receptor using disuccinimidyl suberate and solubilized. Two radioactive bands of m.w. 55,000 and 33,000 were seen when the solubilized crosslinked receptor was electrophoresed on SDS gels. The authors are currently using a combination of HPLC immunoaffinity and reverse-phase chromatography to purify the receptor. The initial studies indicate that the receptor can be purified to homogeneity using this approach. The biochemical characterization of this receptor should provide a better understanding of its importance not only on lymphocytes, but in other tissues as well.

  9. Efficient Amide Based Halogenide Anion Receptors

    Institute of Scientific and Technical Information of China (English)

    Hong Xing WU; Feng Hua LI; Hai LIN; Shou Rong ZHU; Hua Kuan LIN

    2005-01-01

    In this paper, we present the synthesis and anion recognition properties of the amide based phenanthroline derivatives 1, 2 and 3. In all cases 1:1 receptor: anion complexes were observed. The receptors were found to be selective for fluoride and chloride respectively over other putative anionic guest species.

  10. Bitter taste receptors influence glucose homeostasis.

    Science.gov (United States)

    Dotson, Cedrick D; Zhang, Lan; Xu, Hong; Shin, Yu-Kyong; Vigues, Stephan; Ott, Sandra H; Elson, Amanda E T; Choi, Hyun Jin; Shaw, Hillary; Egan, Josephine M; Mitchell, Braxton D; Li, Xiaodong; Steinle, Nanette I; Munger, Steven D

    2008-01-01

    TAS1R- and TAS2R-type taste receptors are expressed in the gustatory system, where they detect sweet- and bitter-tasting stimuli, respectively. These receptors are also expressed in subsets of cells within the mammalian gastrointestinal tract, where they mediate nutrient assimilation and endocrine responses. For example, sweeteners stimulate taste receptors on the surface of gut enteroendocrine L cells to elicit an increase in intracellular Ca(2+) and secretion of the incretin hormone glucagon-like peptide-1 (GLP-1), an important modulator of insulin biosynthesis and secretion. Because of the importance of taste receptors in the regulation of food intake and the alimentary responses to chemostimuli, we hypothesized that differences in taste receptor efficacy may impact glucose homeostasis. To address this issue, we initiated a candidate gene study within the Amish Family Diabetes Study and assessed the association of taste receptor variants with indicators of glucose dysregulation, including a diagnosis of type 2 diabetes mellitus and high levels of blood glucose and insulin during an oral glucose tolerance test. We report that a TAS2R haplotype is associated with altered glucose and insulin homeostasis. We also found that one SNP within this haplotype disrupts normal responses of a single receptor, TAS2R9, to its cognate ligands ofloxacin, procainamide and pirenzapine. Together, these findings suggest that a functionally compromised TAS2R receptor negatively impacts glucose homeostasis, providing an important link between alimentary chemosensation and metabolic disease.

  11. Teaching Receptor Theory to Biochemistry Undergraduates

    Science.gov (United States)

    Benore-Parsons, Marilee; Sufka, Kenneth J.

    2003-01-01

    Receptor:ligand interactions account for numerous reactions critical to biochemistry and molecular biology. While students are typically exposed to some examples, such as hemoglobin binding of oxygen and signal transduction pathways, the topic could easily be expanded. Theory and kinetic analysis, types of receptors, and the experimental assay…

  12. Nanobiosensors based on individual olfactory receptors

    CERN Document Server

    Pajot-Augy, E

    2008-01-01

    In the SPOT-NOSED European project, nanoscale sensing elements bearing olfactory receptors and grafted onto functionalized gold substrates are used as odorant detectors to develop a new concept of nanobioelectronic nose, through sensitive impedancemetric measurement of single receptor conformational change upon ligand binding, with a better specificity and lower detection threshold than traditional physical sensors.

  13. Primary Structure of Nicotinic Acetylcholine Receptor

    Science.gov (United States)

    1986-08-01

    quantities of starting material (for reviews of receptor, see Popot and Changeux, 1984; Stroud and Finer-Moore, 1985). This work led to the...Cloning of the Acetylcholine Receptor. Cold Spring Harbor Symp. on Quant. Biol. XLVIH: 71-78. 15. Popot , J-L. and Changeux, J-P. (1984) The

  14. Adenosine Receptors: Expression, Function and Regulation

    Directory of Open Access Journals (Sweden)

    Sandeep Sheth

    2014-01-01

    Full Text Available Adenosine receptors (ARs comprise a group of G protein-coupled receptors (GPCR which mediate the physiological actions of adenosine. To date, four AR subtypes have been cloned and identified in different tissues. These receptors have distinct localization, signal transduction pathways and different means of regulation upon exposure to agonists. This review will describe the biochemical characteristics and signaling cascade associated with each receptor and provide insight into how these receptors are regulated in response to agonists. A key property of some of these receptors is their ability to serve as sensors of cellular oxidative stress, which is transmitted by transcription factors, such as nuclear factor (NF-κB, to regulate the expression of ARs. Recent observations of oligomerization of these receptors into homo- and heterodimers will be discussed. In addition, the importance of these receptors in the regulation of normal and pathological processes such as sleep, the development of cancers and in protection against hearing loss will be examined.

  15. Thermogenic characterization of ghrelin receptor null mice

    Science.gov (United States)

    Ghrelin is the only known circulating orexigenic hormone that increases food intake and promotes adiposity, and these physiological functions of ghrelin are mediated through its receptor growth hormone secretagogue receptor (GHS-R). Ghrelin/GHS-R signaling plays a crucial role in energy homeostasis....

  16. The delta opioid receptor tool box.

    Science.gov (United States)

    Vicente-Sanchez, Ana; Segura, Laura; Pradhan, Amynah A

    2016-12-03

    In recent years, the delta opioid receptor has attracted increasing interest as a target for the treatment of chronic pain and emotional disorders. Due to their therapeutic potential, numerous tools have been developed to study the delta opioid receptor from both a molecular and a functional perspective. This review summarizes the most commonly available tools, with an emphasis on their use and limitations. Here, we describe (1) the cell-based assays used to study the delta opioid receptor. (2) The features of several delta opioid receptor ligands, including peptide and non-peptide drugs. (3) The existing approaches to detect delta opioid receptors in fixed tissue, and debates that surround these techniques. (4) Behavioral assays used to study the in vivo effects of delta opioid receptor agonists; including locomotor stimulation and convulsions that are induced by some ligands, but not others. (5) The characterization of genetically modified mice used specifically to study the delta opioid receptor. Overall, this review aims to provide a guideline for the use of these tools with the final goal of increasing our understanding of delta opioid receptor physiology.

  17. In vivo studies of opiate receptors

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.J.; Dannals, R.F.; Duelfer, T.; Burns, H.D.; Ravert, H.T.; Langstroem, B.; Balasubramanian, V.; Wagner, H.N. Jr.

    1984-01-01

    To study opiate receptors noninvasively in vivo using positron emission tomography, techniques for preferentially labeling opiate receptors in vivo can be used. The rate at which receptor-bound ligand clears from the brain in vivo can be predicted by measuring the equilibrium dissociation constant (KD) at 37 degrees C in the presence of 100 mM sodium chloride and 100 microM guanyl-5'-imidodiphosphate, the drug distribution coefficient, and the molecular weight. A suitable ligand for labeling opiate receptors in vivo is diprenorphine, which binds to mu, delta, and kappa receptors with approximately equal affinity in vitro. However, in vivo diprenorphine may bind predominantly to one opiate receptor subtype, possibly the mu receptor. To predict the affinity for binding to the opiate receptor, a Hansch correlation was determined between the 50% inhibitory concentration for a series of halogen-substituted fentanyl analogs and electronic, lipophilic, and steric parameters. Radiochemical methods for the synthesis of carbon-11-labeled diprenorphine and lofentanil are presented.

  18. The exportomer: the peroxisomal receptor export machinery.

    Science.gov (United States)

    Platta, Harald W; Hagen, Stefanie; Erdmann, Ralf

    2013-04-01

    Peroxisomes constitute a dynamic compartment of almost all eukaryotic cells. Depending on environmental changes and cellular demands peroxisomes can acquire diverse metabolic roles. The compartmentalization of peroxisomal matrix enzymes is a prerequisite to carry out their physiologic function. The matrix proteins are synthesized on free ribosomes in the cytosol and are ferried to the peroxisomal membrane by specific soluble receptors. Subsequent to cargo release into the peroxisomal matrix, the receptors are exported back to the cytosol to facilitate further rounds of matrix protein import. This dislocation step is accomplished by a remarkable machinery, which comprises enzymes required for the ubiquitination as well as the ATP-dependent extraction of the receptor from the membrane. Interestingly, receptor ubiquitination and dislocation are the only known energy-dependent steps in the peroxisomal matrix protein import process. The current view is that the export machinery of the receptors might function as molecular motor not only in the dislocation of the receptors but also in the import step of peroxisomal matrix protein by coupling ATP-dependent removal of the peroxisomal import receptor with cargo translocation into the organelle. In this review we will focus on the architecture and function of the peroxisomal receptor export machinery, the peroxisomal exportomer.

  19. Regulation of gonadotropin receptor gene expression

    NARCIS (Netherlands)

    A.P.N. Themmen (Axel); R. Kraaij (Robert); J.A. Grootegoed (Anton)

    1994-01-01

    textabstractThe receptors for the gonadotropins differ from the other G protein-coupled receptors by having a large extracellular hormone-binding domain, encoded by nine or ten exons. Alternative splicing of the large pre-mRNA of approximately 100 kb can result in mRNA species that encode truncated

  20. Engineering Hybrid Chemotaxis Receptors in Bacteria.

    Science.gov (United States)

    Bi, Shuangyu; Pollard, Abiola M; Yang, Yiling; Jin, Fan; Sourjik, Victor

    2016-09-16

    Most bacteria use transmembrane sensors to detect a wide range of environmental stimuli. A large class of such sensors are the chemotaxis receptors used by motile bacteria to follow environmental chemical gradients. In Escherichia coli, chemotaxis receptors are known to mediate highly sensitive responses to ligands, making them potentially useful for biosensory applications. However, with only four ligand-binding chemotaxis receptors, the natural ligand spectrum of E. coli is limited. The design of novel chemoreceptors to extend the sensing capabilities of E. coli is therefore a critical aspect of chemotaxis-based biosensor development. One path for novel sensor design is to harvest the large natural diversity of chemosensory functions found in bacteria by creating hybrids that have the signaling domain from E. coli chemotaxis receptors and sensory domains from other species. In this work, we demonstrate that the E. coli receptor Tar can be successfully combined with most typical sensory domains found in chemotaxis receptors and in evolutionary-related two-component histidine kinases. We show that such functional hybrids can be generated using several different fusion points. Our work further illustrates how hybrid receptors could be used to quantitatively characterize ligand specificity of chemotaxis receptors and histidine kinases using standardized assays in E. coli.

  1. Bitter taste receptors influence glucose homeostasis.

    Directory of Open Access Journals (Sweden)

    Cedrick D Dotson

    Full Text Available TAS1R- and TAS2R-type taste receptors are expressed in the gustatory system, where they detect sweet- and bitter-tasting stimuli, respectively. These receptors are also expressed in subsets of cells within the mammalian gastrointestinal tract, where they mediate nutrient assimilation and endocrine responses. For example, sweeteners stimulate taste receptors on the surface of gut enteroendocrine L cells to elicit an increase in intracellular Ca(2+ and secretion of the incretin hormone glucagon-like peptide-1 (GLP-1, an important modulator of insulin biosynthesis and secretion. Because of the importance of taste receptors in the regulation of food intake and the alimentary responses to chemostimuli, we hypothesized that differences in taste receptor efficacy may impact glucose homeostasis. To address this issue, we initiated a candidate gene study within the Amish Family Diabetes Study and assessed the association of taste receptor variants with indicators of glucose dysregulation, including a diagnosis of type 2 diabetes mellitus and high levels of blood glucose and insulin during an oral glucose tolerance test. We report that a TAS2R haplotype is associated with altered glucose and insulin homeostasis. We also found that one SNP within this haplotype disrupts normal responses of a single receptor, TAS2R9, to its cognate ligands ofloxacin, procainamide and pirenzapine. Together, these findings suggest that a functionally compromised TAS2R receptor negatively impacts glucose homeostasis, providing an important link between alimentary chemosensation and metabolic disease.

  2. Molecular identification of the first SIFamide receptor

    DEFF Research Database (Denmark)

    Jørgensen, Lars M; Hauser, Frank; Cazzamali, Giuseppe

    2006-01-01

    . Database searches revealed SIFamide receptor orthologues in the genomes from the malaria mosquito Anopheles gambiae, the silkworm Bombyx mori, the red flour beetle Tribolium castaneum, and the honey bee Apis mellifera. An alignment of the five insect SIFamide or SIFamide-like receptors showed, again...

  3. Prostanoid Receptors in the Human Vascular Wall

    Directory of Open Access Journals (Sweden)

    Xavier Norel

    2007-01-01

    Full Text Available The mechanisms involved in vascular homeostasis and disease are mostly dependent on the interactions between blood, vascular smooth muscle, and endothelial cells. There is an accumulation of evidence for the involvement of prostanoids, the arachidonic acid metabolites derived from the cyclooxygenase enzymatic pathway, in physiological and/or pathophysiological conditions. In humans, the prostanoids activate different receptors. The classical prostanoid receptors (DP, EP1–4, FP, IP, and TP are localized at the cell plasma or nuclear membrane. In addition, CRTH2 and the nuclear PPAR receptors are two other targets for prostanoids, namely, prostacyclin (PGI2 or the natural derivatives of prostaglandin D2. While there is little information on the role of CRTH2, there are many reports on PPAR activation and the consecutive expression of genes involved in the human vascular system. The role of the classical prostanoid receptors stimulated by PGI2 and thromboxane in the control of the vascular tone has been largely documented, whereas the other receptor subtypes have been overlooked. There is now increasing evidence that suggests a role of PGE2 and the EP receptor subtypes in the control of the human vascular tone and remodeling of the vascular wall. These receptors are also present on leukocytes and platelets, and they are implicated in most of the inflammatory processes within the vascular wall. Consequently, the EP receptor subtypes or isoforms would provide a novel and specific cardiovascular therapeutic approach in the near future.

  4. Steroid Hormone Receptor Signals as Prognosticators for Urothelial Tumor

    Directory of Open Access Journals (Sweden)

    Hiroki Ide

    2015-01-01

    Full Text Available There is a substantial amount of preclinical or clinical evidence suggesting that steroid hormone receptor-mediated signals play a critical role in urothelial tumorigenesis and tumor progression. These receptors include androgen receptor, estrogen receptors, glucocorticoid receptor, progesterone receptor, vitamin D receptor, retinoid receptors, peroxisome proliferator-activated receptors, and others including orphan receptors. In particular, studies using urothelial cancer tissue specimens have demonstrated that elevated or reduced expression of these receptors as well as alterations of their upstream or downstream pathways correlates with patient outcomes. This review summarizes and discusses available data suggesting that steroid hormone receptors and related signals serve as biomarkers for urothelial carcinoma and are able to predict tumor recurrence or progression.

  5. Molecular pharmacology of human NMDA receptors

    DEFF Research Database (Denmark)

    Hedegaard, Maiken; Hansen, Kasper Bø; Andersen, Karen Toftegaard

    2012-01-01

    current knowledge of the relationship between NMDA receptor structure and function. We summarize studies on the biophysical properties of human NMDA receptors and compare these properties to those of rat orthologs. Finally, we provide a comprehensive pharmacological characterization that allows side......-by-side comparison of agonists, un-competitive antagonists, GluN2B-selective non-competitive antagonists, and GluN2C/D-selective modulators at recombinant human and rat NMDA receptors. The evaluation of biophysical properties and pharmacological probes acting at different sites on the receptor suggest...... that the binding sites and conformational changes leading to channel gating in response to agonist binding are highly conserved between human and rat NMDA receptors. In summary, the results of this study suggest that no major detectable differences exist in the pharmacological and functional properties of human...

  6. Complex Pharmacology of Free Fatty Acid Receptors

    DEFF Research Database (Denmark)

    Milligan, Graeme; Shimpukade, Bharat; Ulven, Trond

    2017-01-01

    G protein-coupled receptors (GPCRs) are historically the most successful family of drug targets. In recent times it has become clear that the pharmacology of these receptors is far more complex than previously imagined. Understanding of the pharmacological regulation of GPCRs now extends beyond...... pharmacology have shaped understanding of the complex pharmacology of receptors that recognize and are activated by nonesterified or "free" fatty acids (FFAs). The FFA family of receptors is a recently deorphanized set of GPCRs, the members of which are now receiving substantial interest as novel targets...... for the treatment of metabolic and inflammatory diseases. Further understanding of the complex pharmacology of these receptors will be critical to unlocking their ultimate therapeutic potential....

  7. Insulin receptor what role in breast cancer?

    Science.gov (United States)

    Papa, V; Costantino, A; Belfiore, A

    1997-10-01

    It is commonly believed that the insulin receptor mainly mediates the metabolic effects of insulin, whereas the closely related IGF-I receptor is considered a major factor for the regulation of cell proliferation. Experimental and epidemiological evidence indicates, however, that insulin and insulin receptors may play an important role in breast cancer. This article reviews evidence indicating that (a) insulin receptors are overexpressed in human breast cancer, (b) insulin stimulates growth in breast cancer cells, (c) cells transfected with human insulin receptor may acquire a ligand-dependent transformed phenotype, and (d) breast cancer is associated with insulin resistance and hyperinsulinemia. These findings may open new possibilities in breast cancer prevention, prognosis assessment, and therapy. (Trends Endocrinol Metab 1997; 8:306-312). (c) 1997, Elsevier Science Inc.

  8. Role of retinoic receptors in lung carcinogenesis

    Directory of Open Access Journals (Sweden)

    Renyi-Vamos Ferenc

    2008-07-01

    Full Text Available Abstract Several in vitro and in vivo studies have examined the positive and negative effects of retinoids (vitamin A analogs in premalignant and malignant lesions. Retinoids have been used as chemopreventive and anticancer agents because of their pleiotropic regulator function in cell differentiation, growth, proliferation and apoptosis through interaction with two types of nuclear receptors: retinoic acid receptors and retinoid X receptors. Recent investigations have gradually elucidated the function of retinoids and their signaling pathways and may explain the failure of earlier chemopreventive studies. In this review we have compiled basic and recent knowledge regarding the role of retinoid receptors in lung carcinogenesis. Sensitive and appropriate biological tools are necessary for screening the risk population and monitoring the efficacy of chemoprevention. Investigation of retinoid receptors is important and may contribute to the establishment of new strategies in chemoprevention for high-risk patients and in the treatment of lung cancer.

  9. Chemokine Receptors in Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Goda G. Muralidhar

    2013-12-01

    Full Text Available Ovarian carcinoma is the deadliest gynecologic malignancy with very poor rate of survival, and it is characterized by the presence of vast incurable peritoneal metastasis. Studies of the role of chemokine receptors, a family of proteins belonging to the group of G protein-coupled receptors, in ovarian carcinoma strongly placed this family of membrane receptors as major regulators of progression of this malignancy. In this review, we will discuss the roles that chemokine-receptor interactions play to support angiogenesis, cell proliferation, migration, adhesion, invasion, metastasis, and immune evasion in progression of ovarian carcinoma. Data regarding the role that the chemokine receptors play in the disease progression accumulated insofar strongly suggest that this family of proteins could be good therapeutic targets against ovarian carcinoma.

  10. Human Neuroepithelial Cells Express NMDA Receptors

    Directory of Open Access Journals (Sweden)

    Cappell B

    2003-11-01

    Full Text Available Abstract L-glutamate, an excitatory neurotransmitter, binds to both ionotropic and metabotropic glutamate receptors. In certain parts of the brain the BBB contains two normally impermeable barriers: 1 cerebral endothelial barrier and 2 cerebral epithelial barrier. Human cerebral endothelial cells express NMDA receptors; however, to date, human cerebral epithelial cells (neuroepithelial cells have not been shown to express NMDA receptor message or protein. In this study, human hypothalamic sections were examined for NMDA receptors (NMDAR expression via immunohistochemistry and murine neuroepithelial cell line (V1 were examined for NMDAR via RT-PCR and Western analysis. We found that human cerebral epithelium express protein and cultured mouse neuroepithelial cells express both mRNA and protein for the NMDA receptor. These findings may have important consequences for neuroepithelial responses during excitotoxicity and in disease.

  11. GABAA receptor subtype involvement in addictive behaviour.

    Science.gov (United States)

    Stephens, D N; King, S L; Lambert, J J; Belelli, D; Duka, T

    2017-01-01

    GABAA receptors form the major class of inhibitory neurotransmitter receptors in the mammalian brain. This review sets out to summarize the evidence that variations in genes encoding GABAA receptor isoforms are associated with aspects of addictive behaviour in humans, while animal models of addictive behaviour also implicate certain subtypes of GABAA receptor. In addition to outlining the evidence for the involvement of specific subtypes in addiction, we summarize the particular contributions of these isoforms in control over the functioning of brain circuits, especially the mesolimbic system, and make a first attempt to bring together evidence from several fields to understanding potential involvement of GABAA receptor subtypes in addictive behaviour. While the weight of the published literature is on alcohol dependency, the underlying principles outlined are relevant across a number of different aspects of addictive behaviour. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  12. Structure of Leptin Receptor Related with Obesity

    DEFF Research Database (Denmark)

    Toleikis, Zigmantas

    The hormone leptin is central to obesity, but the molecular processes underlying the activation of the leptin receptor are unknown. To further the understanding of the system, an atomic resolution structure of this cytokine type I receptor in the unbound inactive form and in the activated bound...... of the receptor, while the D5 domain is the central leptin-binding domain, implicated in the first steps of activation. Both domains are characterized by a fibronectin type III fold and both contain a conserved WSXWS motif (X represents an unconserved amino acid residue), a distinct feature of the cytokine...... receptors. This motif is thought to play a major role in correct folding and activation of the receptor. The complex between leptin and the D5CA domain was analyzed using nuclear magnetic resonance spectroscopy and the amino acid residues implicated in the binding were determined. To investigate which parts...

  13. Structure of Leptin Receptor Related with Obesity

    DEFF Research Database (Denmark)

    Toleikis, Zigmantas

    The hormone leptin is central to obesity, but the molecular processes underlying the activation of the leptin receptor are unknown. To further the understanding of the system, an atomic resolution structure of this cytokine type I receptor in the unbound inactive form and in the activated bound...... of the receptor, while the D5 domain is the central leptin-binding domain, implicated in the first steps of activation. Both domains are characterized by a fibronectin type III fold and both contain a conserved WSXWS motif (X represents an unconserved amino acid residue), a distinct feature of the cytokine...... receptors. This motif is thought to play a major role in correct folding and activation of the receptor. The complex between leptin and the D5CA domain was analyzed using nuclear magnetic resonance spectroscopy and the amino acid residues implicated in the binding were determined. To investigate which parts...

  14. The ABA receptors -- we report you decide.

    Science.gov (United States)

    McCourt, Peter; Creelman, Robert

    2008-10-01

    The plant hormone abscisic acid (ABA) has been implicated in a variety of physiological responses ranging from seed dormancy to stomatal conductance. Recently, three groups have reported the molecular identification of three disparate ABA receptors. Unlike the identification of other hormone receptors, in these three cases high affinity binding to ABA rather than the isolation of ABA insensitive mutants led to these receptor genes. Interestingly, two of the receptors encode genes involved in floral timing and chlorophyll biosynthesis, which are not considered traditional ABA responses. And the third receptor has been clouded in issues of its molecular identity. To clearly determine the roles of these genes in ABA perception it will require placing of these ABA-binding proteins into the rich ABA physiological context that has built up over the years.

  15. Chemical Approaches to Nuclear Receptors in Metabolism

    Science.gov (United States)

    Margolis, Ronald N.; Moore, David D.; Willson, Timothy M.; Guy, R. Kip

    2017-01-01

    The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsored a workshop, “Chemical Approaches to Nuclear Receptors and Metabolism,” in April 2009 to explore how chemical and molecular biology and physiology can be exploited to further our understanding of nuclear receptor structure, function, and role in disease. Signaling cascades involving nuclear receptors are more complex and interrelated than once thought. Nuclear receptors continue to be attractive targets for drug discovery. The overall goal of this workshop was to identify gaps in our understanding of the complexity of ligand activities and begin to address them by (i) increasing the collaboration of investigators from different disciplines, (ii) developing a better understanding of chemical modulation of nuclear receptor action, and (iii) identifying opportunities and roadblocks in the path of translating basic research to discovery of new therapeutics. PMID:19654413

  16. Gβ promotes pheromone receptor polarization and yeast chemotropism by inhibiting receptor phosphorylation.

    Science.gov (United States)

    Ismael, Amber; Tian, Wei; Waszczak, Nicholas; Wang, Xin; Cao, Youfang; Suchkov, Dmitry; Bar, Eli; Metodiev, Metodi V; Liang, Jie; Arkowitz, Robert A; Stone, David E

    2016-04-12

    Gradient-directed cell migration (chemotaxis) and growth (chemotropism) are processes that are essential to the development and life cycles of all species. Cells use surface receptors to sense the shallow chemical gradients that elicit chemotaxis and chemotropism. Slight asymmetries in receptor activation are amplified by downstream signaling systems, which ultimately induce dynamic reorganization of the cytoskeleton. During the mating response of budding yeast, a model chemotropic system, the pheromone receptors on the plasma membrane polarize to the side of the cell closest to the stimulus. Although receptor polarization occurs before and independently of actin cable-dependent delivery of vesicles to the plasma membrane (directed secretion), it requires receptor internalization. Phosphorylation of pheromone receptors by yeast casein kinase 1 or 2 (Yck1/2) stimulates their internalization. We showed that the pheromone-responsive Gβγ dimer promotes the polarization of the pheromone receptor by interacting with Yck1/2 and locally inhibiting receptor phosphorylation. We also found that receptor phosphorylation is essential for chemotropism, independently of its role in inducing receptor internalization. A mathematical model supports the idea that the interaction between Gβγ and Yck1/2 results in differential phosphorylation and internalization of the pheromone receptor and accounts for its polarization before the initiation of directed secretion.

  17. Real-Time G-Protein-Coupled Receptor Imaging to Understand and Quantify Receptor Dynamics

    Directory of Open Access Journals (Sweden)

    María S. Aymerich

    2011-01-01

    Full Text Available Understanding the trafficking of G-protein-coupled receptors (GPCRs and their regulation by agonists and antagonists is fundamental to develop more effective drugs. Optical methods using fluorescent-tagged receptors and spinning disk confocal microscopy are useful tools to investigate membrane receptor dynamics in living cells. The aim of this study was to develop a method to characterize receptor dynamics using this system which offers the advantage of very fast image acquisition with minimal cell perturbation. However, in short-term assays photobleaching was still a problem. Thus, we developed a procedure to perform a photobleaching-corrected image analysis. A study of short-term dynamics of the long isoform of the dopamine type 2 receptor revealed an agonist-induced increase in the mobile fraction of receptors with a rate of movement of 0.08 μm/s For long-term assays, the ratio between the relative fluorescence intensity at the cell surface versus that in the intracellular compartment indicated that receptor internalization only occurred in cells co-expressing G protein-coupled receptor kinase 2. These results indicate that the lateral movement of receptors and receptor internalization are not directly coupled. Thus, we believe that live imaging of GPCRs using spinning disk confocal image analysis constitutes a powerful tool to study of receptor dynamics.

  18. 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...

  19. The use of receptor-specific antibodies to study G-protein-coupled receptors.

    Science.gov (United States)

    Gupta, Achla; Devi, Lakshmi A

    2006-07-01

    The identification of G-protein-coupled receptor (GPCR) cDNAs has facilitated a number of studies characterizing the biochemical properties of the receptor protein. Most of these studies have used antibodies directed against the epitope-tagged receptor expressed in heterologous cells, because of the lack of sensitive and selective antibodies capable of recognizing endogenous receptors in their native state. In order to facilitate studies with endogenous receptors, efforts have been made to generate receptor-type selective, sensitive antibodies that are able to recognize endogenous receptors. In this review, we discuss the strategies as well as the details of the techniques used for the generation of monoclonal and polyclonal antibodies with a focus on family A GPCRs.

  20. Endocytosis of Receptor Tyrosine Kinases

    Science.gov (United States)

    Goh, Lai Kuan

    2013-01-01

    Endocytosis is the major regulator of signaling from receptor tyrosine kinases (RTKs). The canonical model of RTK endocytosis involves rapid internalization of an RTK activated by ligand binding at the cell surface and subsequent sorting of internalized ligand-RTK complexes to lysosomes for degradation. Activation of the intrinsic tyrosine kinase activity of RTKs results in autophosphorylation, which is mechanistically coupled to the recruitment of adaptor proteins and conjugation of ubiquitin to RTKs. Ubiquitination serves to mediate interactions of RTKs with sorting machineries both at the cell surface and on endosomes. The pathways and kinetics of RTK endocytic trafficking, molecular mechanisms underlying sorting processes, and examples of deviations from the standard trafficking itinerary in the RTK family are discussed in this work. PMID:23637288

  1. THE NATURE OF ACETYLCHOLINE RECEPTOR

    Directory of Open Access Journals (Sweden)

    M.E. TASHAYOD

    1983-05-01

    Full Text Available The present work with consideratlon to the autoradiographic pictures, suggests that cholinergic receptors are located at the gate of a channel originating from synaptic cleft coming to lie within the muscle fibre. AChE molecules stand at the gate of this channel,controlling the entrance of different cholinergic agents. It was report- ••• ed previously that dtc molecules s t.abD ;:.2e the AChE rnolecules and will obstruct the gate. This blocks the acess of ionic flux within the channel thus producing a non-depolarizing neuromuscular paralysis.The presented experiments imply that depolarizing agent will bring a considerable change in conformation of AChE mole cule and this causes the opening of the gate allowing ioni flux and depolarization .In case of ACh this process is repeated in a fraction of milli second, due to rapid regeneration of AChE while in case of suxamethonium and neostigmine(given in high dose, the regeneration of AChE takes much longer time thus will produce a depolarizing blockade. In this hypothepis the main responsa~ility of AChE"nis confined to identification of cholinergic agents and Cooperation in their function so,it can be accepted as Cholinergic receptor. In regard to clinic, this work suggests that only the use of minimum effective dose of neostigmine is advisable, in reversing curarisation. In contrast to general belief , the dose of neostigmine should be s elec t ed in relation to r eceptor dtc occupation and not depending on pati ent 's weight . As it was demonstrated , the early use"nof high dose o f neostigmine may a lso potent i a te curar i s a tion

  2. Stoichiometry of δ subunit containing GABAA receptors

    Science.gov (United States)

    Patel, B; Mortensen, M; Smart, T G

    2014-01-01

    Background and Purpose Although the stoichiometry of the major synaptic αβγ subunit-containing GABAA receptors has consensus support for 2α:2β:1γ, a clear view of the stoichiometry of extrasynaptic receptors containing δ subunits has remained elusive. Here we examine the subunit stoichiometry of recombinant α4β3δ receptors using a reporter mutation and a functional electrophysiological approach. Experimental Approach Using site-directed mutagenesis, we inserted a highly characterized 9′ serine to leucine mutation into the second transmembrane (M2) region of α4, β3 and δ subunits that increases receptor sensitivity to GABA. Whole-cell, GABA-activated currents were recorded from HEK-293 cells co-expressing different combinations of wild-type (WT) and/or mutant α4(L297S), β3(L284S) and δ(L288S) subunits. Key Results Recombinant receptors containing one or more mutant subunits showed increased GABA sensitivity relative to WT receptors by approximately fourfold, independent of the subunit class (α, β or δ) carrying the mutation. GABA dose–response curves of cells co-expressing WT subunits with their respective L9′S mutants exhibited multiple components, with the number of discernible components enabling a subunit stoichiometry of 2α, 2β and 1δ to be deduced for α4β3δ receptors. Varying the cDNA transfection ratio by 10-fold had no significant effect on the number of incorporated δ subunits. Conclusions and Implications Subunit stoichiometry is an important determinant of GABAA receptor function and pharmacology, and δ subunit-containing receptors are important mediators of tonic inhibition in several brain regions. Here we demonstrate a preferred subunit stoichiometry for α4β3δ receptors of 2α, 2β and 1δ. PMID:24206220

  3. Solution assembly of cytokine receptor ectodomain complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zining; Ciardelli, T.L. [Dartmouth Medical School, Hanover, NH (United States). Dept. of Pharmacology and Toxicology; Johnson, K.W. [Chiron Corp., Emeryville, CA (United States)] [and others

    1995-09-01

    For the majority of single transmembrane-spanning cell surface receptors, signal transmission across the lipid bilayer barrier involves several discrete components of molecular recognition. The interaction between ligand and the extracellular segment of its cognate receptor (ectodomain) initiates either homomeric or heteromeric association of receptor subunits. Specific recognition among these subunits may then occur between ectodomain regions, within the membrane by interhelical contact or inside the cell between cytoplasmic domains. Any or all of these interactions may contribute to the stability of the signaling complex. It is the characteristics of ligand binding by the ectodomains of these receptors that controls the heteromeric or homomeric nature and the stoichiometry of the complex. Cytokines and their receptors belong to a growing family of macromolecular systems that exhibit these functional features and share many structural similarities as well. Interleukin-2 is a multifunctional cytokine that represents, perhaps, the most complex example to date of ligand recognition among the hematopoietin receptor family. It is the cooperative binding of IL-2 by all three proteins on the surface of activated T-lymphocytes, however, that ultimately results in crosslinking of the {beta}- and {gamma}-subunits and signaling via association of their cytoplasmic domains. Although the high-affinity IL-2R functions as a heterotrimer, heterodimers of the receptor subunits are also physiologically important. The {alpha}/{beta} heterodimer or {open_quotes}pseudo-high affinity{close_quotes} receptor captures IL-2 as a preformed cell surface complex while the {beta}/{gamma} intermediate affinity site exists, in the absence of the {alpha} subunit, on the majority of natural killer cells. We have begun to study stable complexes of cytokine receptor ectodomains of defined composition and that mimic the ligand binding characteristics of the equivalent cell surface receptor sites.

  4. Enhanced human receptor binding by H5 haemagglutinins

    OpenAIRE

    Xiong, Xiaoli; Xiao, Haixia; Martin, Stephen R.; Coombs, Peter J.; Liu, Junfeng; Collins, Patrick J.; Vachieri, Sebastien G.; Walker, Philip A.; Lin, Yi Pu; McCauley, John W.; Gamblin, Steven J.; John J Skehel

    2014-01-01

    Mutant H5N1 influenza viruses have been isolated from humans that have increased human receptor avidity. We have compared the receptor binding properties of these mutants with those of wild-type viruses, and determined the structures of their haemagglutinins in complex with receptor analogues. Mutants from Vietnam bind tighter to human receptor by acquiring basic residues near the receptor binding site. They bind more weakly to avian receptor because they lack specific interactions between As...

  5. Cocaine Inhibits Dopamine D2 Receptor Signaling via Sigma-1-D2 Receptor Heteromers

    Science.gov (United States)

    Navarro, Gemma; Moreno, Estefania; Bonaventura, Jordi; Brugarolas, Marc; Farré, Daniel; Aguinaga, David; Mallol, Josefa; Cortés, Antoni; Casadó, Vicent; Lluís, Carmen; Ferre, Sergi

    2013-01-01

    Under normal conditions the brain maintains a delicate balance between inputs of reward seeking controlled by neurons containing the D1-like family of dopamine receptors and inputs of aversion coming from neurons containing the D2-like family of dopamine receptors. Cocaine is able to subvert these balanced inputs by altering the cell signaling of these two pathways such that D1 reward seeking pathway dominates. Here, we provide an explanation at the cellular and biochemical level how cocaine may achieve this. Exploring the effect of cocaine on dopamine D2 receptors function, we present evidence of σ1 receptor molecular and functional interaction with dopamine D2 receptors. Using biophysical, biochemical, and cell biology approaches, we discovered that D2 receptors (the long isoform of the D2 receptor) can complex with σ1 receptors, a result that is specific to D2 receptors, as D3 and D4 receptors did not form heteromers. We demonstrate that the σ1-D2 receptor heteromers consist of higher order oligomers, are found in mouse striatum and that cocaine, by binding to σ1 -D2 receptor heteromers, inhibits downstream signaling in both cultured cells and in mouse striatum. In contrast, in striatum from σ1 knockout animals these complexes are not found and this inhibition is not seen. Taken together, these data illuminate the mechanism by which the initial exposure to cocaine can inhibit signaling via D2 receptor containing neurons, destabilizing the delicate signaling balance influencing drug seeking that emanates from the D1 and D2 receptor containing neurons in the brain. PMID:23637801

  6. Cocaine inhibits dopamine D2 receptor signaling via sigma-1-D2 receptor heteromers.

    Directory of Open Access Journals (Sweden)

    Gemma Navarro

    Full Text Available Under normal conditions the brain maintains a delicate balance between inputs of reward seeking controlled by neurons containing the D1-like family of dopamine receptors and inputs of aversion coming from neurons containing the D2-like family of dopamine receptors. Cocaine is able to subvert these balanced inputs by altering the cell signaling of these two pathways such that D1 reward seeking pathway dominates. Here, we provide an explanation at the cellular and biochemical level how cocaine may achieve this. Exploring the effect of cocaine on dopamine D2 receptors function, we present evidence of σ1 receptor molecular and functional interaction with dopamine D2 receptors. Using biophysical, biochemical, and cell biology approaches, we discovered that D2 receptors (the long isoform of the D2 receptor can complex with σ1 receptors, a result that is specific to D2 receptors, as D3 and D4 receptors did not form heteromers. We demonstrate that the σ1-D2 receptor heteromers consist of higher order oligomers, are found in mouse striatum and that cocaine, by binding to σ1 -D2 receptor heteromers, inhibits downstream signaling in both cultured cells and in mouse striatum. In contrast, in striatum from σ1 knockout animals these complexes are not found and this inhibition is not seen. Taken together, these data illuminate the mechanism by which the initial exposure to cocaine can inhibit signaling via D2 receptor containing neurons, destabilizing the delicate signaling balance influencing drug seeking that emanates from the D1 and D2 receptor containing neurons in the brain.

  7. Membrane topology of insulin receptors reconstituted into lipid vesicles

    DEFF Research Database (Denmark)

    Tranum-Jensen, Jørgen; Christiansen, K.; Carlsen, Jens;

    1994-01-01

    Anatomy, insulin receptors, membrane reconstitution, electron microscopy, quaternary structure, immunogold labeling......Anatomy, insulin receptors, membrane reconstitution, electron microscopy, quaternary structure, immunogold labeling...

  8. Pattern-recognition receptors in human eosinophils.

    Science.gov (United States)

    Kvarnhammar, Anne Månsson; Cardell, Lars Olaf

    2012-05-01

    The pattern-recognition receptor (PRR) family includes Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD) -like receptors (NLRs), RIG-I-like receptors (RLRs), C-type lectin receptors (CLRs) and the receptor for advanced glycation end products (RAGE). They recognize various microbial signatures or host-derived danger signals and trigger an immune response. Eosinophils are multifunctional leucocytes involved in the pathogenesis of several inflammatory processes, including parasitic helminth infection, allergic diseases, tissue injury and tumour immunity. Human eosinophils express several PRRs, including TLR1-5, TLR7, TLR9, NOD1, NOD2, Dectin-1 and RAGE. Receptor stimulation induces survival, oxidative burst, activation of the adhesion system and release of cytokines (interleukin-1β, interleukin-6, tumour necrosis factor-α and granulocyte-macrophage colony-stimulating factor), chemokines (interleukin-8 and growth-related oncogene-α) and cytotoxic granule proteins (eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase and major basic protein). It is also evident that eosinophils play an immunomodulatory role by interacting with surrounding cells. The presence of a broad range of PRRs in eosinophils indicates that they are not only involved in defence against parasitic helminths, but also against bacteria, viruses and fungi. From a clinical perspective, eosinophilic PRRs seem to be involved in both allergic and malignant diseases by causing exacerbations and affecting tumour growth, respectively.

  9. Muscarinic Receptor Signaling in Colon Cancer

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Raufman

    2011-03-01

    Full Text Available According to the adenoma-carcinoma sequence, colon cancer results from accumulating somatic gene mutations; environmental growth factors accelerate and augment this process. For example, diets rich in meat and fat increase fecal bile acids and colon cancer risk. In rodent cancer models, increased fecal bile acids promote colon dysplasia. Conversely, in rodents and in persons with inflammatory bowel disease, low-dose ursodeoxycholic acid treatment alters fecal bile acid composition and attenuates colon neoplasia. In the course of elucidating the mechanism underlying these actions, we discovered that bile acids interact functionally with intestinal muscarinic receptors. The present communication reviews muscarinic receptor expression in normal and neoplastic colon epithelium, the role of autocrine signaling following synthesis and release of acetylcholine from colon cancer cells, post-muscarinic receptor signaling including the role of transactivation of epidermal growth factor receptors and activation of the ERK and PI3K/AKT signaling pathways, the structural biology and metabolism of bile acids and evidence for functional interaction of bile acids with muscarinic receptors on human colon cancer cells. In murine colon cancer models, deficiency of subtype 3 muscarinic receptors attenuates intestinal neoplasia; a proof-of-concept supporting muscarinic receptor signaling as a therapeutic target for colon cancer.

  10. Purinergic Receptors in Thrombosis and Inflammation.

    Science.gov (United States)

    Hechler, Béatrice; Gachet, Christian

    2015-11-01

    Under various pathological conditions, including thrombosis and inflammation, extracellular nucleotide levels may increase because of both active release and passive leakage from damaged or dying cells. Once in the extracellular compartment, nucleotides interact with plasma membrane receptors belonging to the P2 purinergic family, which are expressed by virtually all circulating blood cells and in most blood vessels. In this review, we focus on the specific role of the 3 platelet P2 receptors P2Y1, P2Y12, and P2X1 in hemostasis and arterial thrombosis. Beyond platelets, these 3 receptors, along with the P2Y2, P2Y6, and P2X7 receptors, constitute the main P2 receptors mediating the proinflammatory effects of nucleotides, which play important roles in various functions of circulating blood cells and cells of the vessel wall. Each of these P2 receptor subtypes specifically contributes to chronic or acute vascular inflammation and related diseases, such as atherosclerosis, restenosis, endotoxemia, and sepsis. The potential for therapeutic targeting of these P2 receptor subtypes is also discussed.

  11. GABA B receptor subunit expression in glia.

    Science.gov (United States)

    Charles, K J; Deuchars, J; Davies, C H; Pangalos, M N

    2003-09-01

    GABA(B) receptor subunits are widely expressed on neurons throughout the CNS, at both pre- and postsynaptic sites, where they mediate the late, slow component of the inhibitory response to the major inhibitory neurotransmitter GABA. The existence of functional GABA(B) receptors on nonneuronal cells has been reported previously, although the molecular composition of these receptors has not yet been described. Here we demonstrate for the first time, using immunohistochemistry the expression of GABA(B1a), GABA(B1b), and GABA(B2) on nonneuronal cells of the rat CNS. All three principle GABA(B) receptor subunits were expressed on these cells irrespective of whether they had been cultured or found within brain tissue sections. At the ultrastructural level GABA(B) receptor subunits were expressed on astrocytic processes surrounding both symmetrical and assymetrical synapses in the CA1 subregion of the hippocampus. In addition, GABA(B1a), GABA(B1b), and GABA(B2) receptor subunits were expressed on activated microglia in culture but were not found on myelin forming oligodendrocytes in the white matter of rat spinal cord. Together these data demonstrate that the obligate subunits of functional GABA(B) receptors are expressed in astrocytes and microglia in the rat CNS.

  12. Action mechanisms of Liver X Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Gabbi, Chiara; Warner, Margaret [Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas (United States); Gustafsson, Jan-Åke, E-mail: jgustafs@central.uh.edu [Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas (United States); Department of Biosciences and Nutrition, Karolinska Institutet, Novum S-141 86 (Sweden)

    2014-04-11

    Highlights: • LXRα and LXRβ are ligand-activated nuclear receptors. • They share oxysterol ligands and the same heterodimerization partner, RXR. • LXRs regulate lipid and glucose metabolism, CNS and immune functions, and water transport. - Abstract: The two Liver X Receptors, LXRα and LXRβ, are nuclear receptors belonging to the superfamily of ligand-activated transcription factors. They share more than 78% homology in amino acid sequence, a common profile of oxysterol ligands and the same heterodimerization partner, Retinoid X Receptor. LXRs play crucial roles in several metabolic pathways: lipid metabolism, in particular in preventing cellular cholesterol accumulation; glucose homeostasis; inflammation; central nervous system functions and water transport. As with all nuclear receptors, the transcriptional activity of LXR is the result of an orchestration of numerous cellular factors including ligand bioavailability, presence of corepressors and coactivators and cellular context i.e., what other pathways are activated in the cell at the time the receptor recognizes its ligand. In this mini-review we summarize the factors regulating the transcriptional activity and the mechanisms of action of these two receptors.

  13. Tachykinin receptors in the equine pelvic flexure.

    Science.gov (United States)

    Sonea, I M; Wilson, D V; Bowker, R M; Robinson, N E

    1997-07-01

    Tachykinins, of which substance P (SP) is the prototype, are neuropeptides which are widely distributed in the nervous systems. In the equine gut, SP is present in enteric nerves and is a powerful constrictor of enteric muscle; in other species, SP is also known to have potent vasodilatory and pro-inflammatory effects. The specific effects of SP are determined by the subtype of receptor present in the target tissue. There are 3 known subtypes of tachykinin receptors, distinguished by their relative affinities for SP and other tachykinins. The distribution of SP binding sites in the equine pelvic flexure was determined using 125I-Bolton Hunter SP (I-BHSP) autoradiography. Most I-BHSP binding sites were determined to be saturable and specific, therefore presumably representing tachykinin receptors. The greatest degree of I-BHSP binding occurred over very small vessels, and over the muscularis mucosae; I-BHSP binding was also intense over the circular muscle of the muscularis externa and mucosa, and present, although less intense, over the longitudinal muscle of the muscularis externa. Competition of I-BHSP with specific receptor agonists for binding sites in the equine pelvic flexure were used to determine the subtypes of tachykinin receptors present. The neurokinin-1 receptor subtype predominated in the equine pelvic flexure, followed by the neurokinin-3 receptor subtype.

  14. Muscarinic Receptor Signaling in Colon Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Rosenvinge, Erik C. von, E-mail: evonrose@medicine.umaryland.edu; Raufman, Jean-Pierre [University of Maryland School of Medicine, Division of Gastroenterology & Hepatology, 22 S. Greene Street, N3W62, Baltimore, MD 21201 (United States); Department of Veterans Affairs, VA Maryland Health Care System, 10 North Greene Street, Baltimore, MD 21201 (United States)

    2011-03-02

    According to the adenoma-carcinoma sequence, colon cancer results from accumulating somatic gene mutations; environmental growth factors accelerate and augment this process. For example, diets rich in meat and fat increase fecal bile acids and colon cancer risk. In rodent cancer models, increased fecal bile acids promote colon dysplasia. Conversely, in rodents and in persons with inflammatory bowel disease, low-dose ursodeoxycholic acid treatment alters fecal bile acid composition and attenuates colon neoplasia. In the course of elucidating the mechanism underlying these actions, we discovered that bile acids interact functionally with intestinal muscarinic receptors. The present communication reviews muscarinic receptor expression in normal and neoplastic colon epithelium, the role of autocrine signaling following synthesis and release of acetylcholine from colon cancer cells, post-muscarinic receptor signaling including the role of transactivation of epidermal growth factor receptors and activation of the ERK and PI3K/AKT signaling pathways, the structural biology and metabolism of bile acids and evidence for functional interaction of bile acids with muscarinic receptors on human colon cancer cells. In murine colon cancer models, deficiency of subtype 3 muscarinic receptors attenuates intestinal neoplasia; a proof-of-concept supporting muscarinic receptor signaling as a therapeutic target for colon cancer.

  15. Androgen receptor expression in gastrointestinal stromal tumor.

    Science.gov (United States)

    Lopes, Lisandro F; Bacchi, Carlos E

    2009-03-01

    The aim of this study was to evaluate the expression of estrogen, progesterone, and androgen receptors in a large series of gastrointestinal stromal tumors. Clinical and pathologic data were reviewed in 427 cases of gastrointestinal stromal tumor and the expression of such hormone receptors was investigated by immunohistochemistry using tissue microarray technique. All tumors were negative for estrogen receptor expression. Progesterone and androgen receptors expression was observed in 5.4% and 17.6% of tumors, respectively. We found the higher average age at diagnosis, the lower frequency of tumors located in the small intestine, and the higher frequency of extragastrointestinal tumors to be statistically significant in the group of tumors with androgen receptor expression in contrast to the group showing no androgen receptor expression. There was no statistic difference between such groups regarding sex, tumor size, mitotic count, cell morphology, and risk of aggressive behavior. Considering that the expression of androgen receptors in gastrointestinal stromal tumors is not negligible, further studies are encouraged to establish the role of androgen deprivation therapy for gastrointestinal stromal tumors.

  16. Role of Prolactin Receptors in Lymphangioleiomyomatosis.

    Directory of Open Access Journals (Sweden)

    Amira Alkharusi

    Full Text Available Pulmonary lymphangioleiomyomatosis (LAM is a rare lung disease caused by mutations in the tumor suppressor genes encoding Tuberous Sclerosis Complex (TSC 1 and TSC2. The protein product of the TSC2 gene is a well-known suppressor of the mTOR pathway. Emerging evidence suggests that the pituitary hormone prolactin (Prl has both endocrine and paracrine modes of action. Here, we have investigated components of the Prl system in models for LAM. In a TSC2 (+/- mouse sarcoma cell line, down-regulation of TSC2 using siRNA resulted in increased levels of the Prl receptor. In human LAM cells, the Prl receptor is detectable by immunohistochemistry, and the expression of Prl in these cells stimulates STAT3 and Erk phosphorylation, as well as proliferation. A high affinity Prl receptor antagonist consisting of Prl with four amino acid substitutions reduced phosphorylation of STAT3 and Erk. Antagonist treatment further reduced the proliferative and invasive properties of LAM cells. In histological sections from LAM patients, Prl receptor immuno reactivity was observed. We conclude that the Prl receptor is expressed in LAM, and that loss of TSC2 increases Prl receptor levels. It is proposed that Prl exerts growth-stimulatory effects on LAM cells, and that antagonizing the Prl receptor can block such effects.

  17. Lessons from crystal structures of kainate receptors.

    Science.gov (United States)

    Møllerud, Stine; Frydenvang, Karla; Pickering, Darryl S; Kastrup, Jette Sandholm

    2017-01-01

    Kainate receptors belong to the family of ionotropic glutamate receptors. These receptors assemble from five subunits (GluK1-5) into tetrameric ion channels. Kainate receptors are located at both pre- and postsynaptic membranes in the central nervous system where they contribute to excitatory synaptic transmission and modulate network excitability by regulating neurotransmitter release. Dysfunction of kainate receptors has been implicated in several neurological disorders such as epilepsy, schizophrenia and depression. Here we provide a review on the current understanding of kainate receptor structure and how they bind agonists, antagonists and ions. The first structure of the ligand-binding domain of the GluK1 subunit was reported in 2005, seven years after publication of the crystal structure of a soluble construct of the ligand-binding domain of the AMPA-type subunit GluA2. Today, a full-length structure has been determined of GluK2 by cryo electron microscopy to 7.6 Å resolution as well as 84 high-resolution crystal structures of N-terminal domains and ligand-binding domains, including agonist and antagonist bound structures, modulatory ions and mutations. However, there are still many unanswered questions and challenges in front of us. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.

  18. The evolution of natural killer cell receptors.

    Science.gov (United States)

    Carrillo-Bustamante, Paola; Keşmir, Can; de Boer, Rob J

    2016-01-01

    Natural killer (NK) cells are immune cells that play a crucial role against viral infections and tumors. To be tolerant against healthy tissue and simultaneously attack infected cells, the activity of NK cells is tightly regulated by a sophisticated array of germline-encoded activating and inhibiting receptors. The best characterized mechanism of NK cell activation is "missing self" detection, i.e., the recognition of virally infected or transformed cells that reduce their MHC expression to evade cytotoxic T cells. To monitor the expression of MHC-I on target cells, NK cells have monomorphic inhibitory receptors which interact with conserved MHC molecules. However, there are other NK cell receptors (NKRs) encoded by gene families showing a remarkable genetic diversity. Thus, NKR haplotypes contain several genes encoding for receptors with activating and inhibiting signaling, and that vary in gene content and allelic polymorphism. But if missing-self detection can be achieved by a monomorphic NKR system why have these polygenic and polymorphic receptors evolved? Here, we review the expansion of NKR receptor families in different mammal species, and we discuss several hypotheses that possibly underlie the diversification of the NK cell receptor complex, including the evolution of viral decoys, peptide sensitivity, and selective MHC-downregulation.

  19. Glucagon receptors: effect of exercise and fasting.

    Science.gov (United States)

    Lavoie, Carole

    2005-06-01

    One paradox of hormonal regulation during exercise is the maintenance of glucose homeostasis after endurance training despite a lower increase in plasma glucagon. One explanation could be that liver sensitivity to glucagon is increased by endurance training. Glucagon exerts its effect through a 62 KDa glycoprotein receptor, member of the G protein-coupled receptor. To determine whether changes with exercise in glucagon sensitivity occurred at the level of the glucagon receptor (GR), binding characteristics of hepatic glucagon receptors were ascertained in rat purified plasma membranes. Saturation kinetics indicated no difference in the dissociation constant or affinity of glucagon receptor, but a significantly higher glucagon receptor binding density in liver in endurance trained compared to untrained animals. Along with endurance training, it appears that fasting also changes GR binding characteristics. In animals fasting 24 hrs, a significant increase in glucagon receptor density was also reported. Although the exact mechanism remains unknown, there is no doubt that the liver can adapt to physiological stress through modulation of GR binding characteristics to enhance the hepatic glucose production responsiveness to glucagon.

  20. Neuromedin B receptors regulate EGF receptor tyrosine phosphorylation in lung cancer cells

    Science.gov (United States)

    Moody, Terry W.; Berna, Marc J.; Mantey, Samuel; Sancho, Veronica; Ridnour, Lisa; Wink, David A.; Chan, Daniel; Giaccone, Giuseppe; Jensen, Robert T.

    2014-01-01

    Neuromedin B (NMB), a member of the bombesin family of peptides, is an autocrine growth factor for many lung cancer cells. The present study investigated the ability of NMB to cause transactivation of the epidermal growth factor (EGF) receptor in lung cancer cells. By Western blot, addition of NMB or related peptides to NCI-H1299 human non-small cell lung cancer (NSCLC) cells, caused phosphorylation of Tyr1068 of the EGF receptor. The signal was amplified using NCI-H1299 cells stably transected with NMB receptors. The transactivation of the EGF receptor or the tyrosine phosphorylation of ERK caused by NMB-like peptides was inhibited by AG1478 or gefitinib (tyrosine kinase inhibitors) and NMB receptor antagonist PD168368 but not the GRP receptor antagonist, BW2258U89. The transactivation of the EGF receptor caused by NMB-like peptides was inhibited by GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor), or transforming growth factor (TGF)α antibody. The transactivation of the EGF receptor and the increase in reactive oxygen species caused by NMB-like peptides was inhibited by N-acetylcysteine (NAC) or Tiron. Gefitinib inhibited the proliferation of NCI-H1299 cells and its sensitivity was increased by the addition of PD168368. The results indicate that the NMB receptor regulates EGF receptor transactivation by a mechanism dependent on Src as well as metalloprotease activation and generation of reactive oxygen species. PMID:20388507

  1. GABAA receptors: post-synaptic co-localization and cross-talk with other receptors

    Directory of Open Access Journals (Sweden)

    Amulya Nidhi Shrivastava

    2011-06-01

    Full Text Available γ-aminobutyric acid type A receptors (GABAARs are the major inhibitory neurotransmitter receptors in the central nervous system (CNS, and importantly contribute to the functional regulation of the nervous system. Several studies in the last few decades have convincingly shown that GABA can be co-localized with other neurotransmitters in the same synapse, and can be co-released with these neurotransmitters either from the same vesicles or from different vesicle pools. The co-released transmitters may act on post-synaptically co-localized receptors resulting in a simultaneous activation of both receptors. Most of the studies investigating such co-activation observed a reduced efficacy of GABA for activating GABAARs and thus, a reduced inhibition of the postsynaptic neuron. Similarly, in several cases activation of GABAARs has been reported to suppress the response of the associated receptors. Such a receptor cross-talk is either mediated via a direct coupling between the two receptors or via the activation of intracellular signaling pathways and is used for fine tuning of inhibition in the nervous system. Recently, it was demonstrated that a direct interaction of different receptors might already occur in intracellular compartments and might also be used to specifically target the receptors to the cell membrane. In this article, we provide an overview on such cross-talks between GABAARs and several other neurotransmitter receptors and briefly discuss their possible physiological and clinical importance.

  2. Adenosine receptor antagonists alter the stability of human epileptic GABAA receptors

    Science.gov (United States)

    Roseti, Cristina; Martinello, Katiuscia; Fucile, Sergio; Piccari, Vanessa; Mascia, Addolorata; Di Gennaro, Giancarlo; Quarato, Pier Paolo; Manfredi, Mario; Esposito, Vincenzo; Cantore, Gianpaolo; Arcella, Antonella; Simonato, Michele; Fredholm, Bertil B.; Limatola, Cristina; Miledi, Ricardo; Eusebi, Fabrizio

    2008-01-01

    We examined how the endogenous anticonvulsant adenosine might influence γ-aminobutyric acid type A (GABAA) receptor stability and which adenosine receptors (ARs) were involved. Upon repetitive activation (GABA 500 μM), GABAA receptors, microtransplanted into Xenopus oocytes from neurosurgically resected epileptic human nervous tissues, exhibited an obvious GABAA-current (IGABA) run-down, which was consistently and significantly reduced by treatment with the nonselective adenosine receptor antagonist CGS15943 (100 nM) or with adenosine deaminase (ADA) (1 units/ml), that inactivates adenosine. It was also found that selective antagonists of A2B (MRS1706, 10 nM) or A3 (MRS1334, 30 nM) receptors reduced IGABA run-down, whereas treatment with the specific A1 receptor antagonist DPCPX (10 nM) was ineffective. The selective A2A receptor antagonist SCH58261 (10 nM) reduced or potentiated IGABA run-down in ≈40% and ≈20% of tested oocytes, respectively. The ADA-resistant, AR agonist 2-chloroadenosine (2-CA) (10 μM) potentiated IGABA run-down but only in ≈20% of tested oocytes. CGS15943 administration again decreased IGABA run-down in patch-clamped neurons from either human or rat neocortex slices. IGABA run-down in pyramidal neurons was equivalent in A1 receptor-deficient and wt neurons but much larger in neurons from A2A receptor-deficient mice, indicating that, in mouse cortex, GABAA-receptor stability is tonically influenced by A2A but not by A1 receptors. IGABA run-down from wt mice was not affected by 2-CA, suggesting maximal ARs activity by endogenous adenosine. Our findings strongly suggest that cortical A2–A3 receptors alter the stability of GABAA receptors, which could offer therapeutic opportunities. PMID:18809912

  3. N-glycosylation of the β2 adrenergic receptor regulates receptor function by modulating dimerization.

    Science.gov (United States)

    Li, Xiaona; Zhou, Mang; Huang, Wei; Yang, Huaiyu

    2017-07-01

    N-glycosylation is a common post-translational modification of G-protein-coupled receptors (GPCRs). However, it remains unknown how N-glycosylation affects GPCR signaling. β2 adrenergic receptor (β2 AR) has three N-glycosylation sites: Asn6, Asn15 at the N-terminus, and Asn187 at the second extracellular loop (ECL2). Here, we show that deletion of the N-glycan did not affect receptor expression and ligand binding. Deletion of the N-glycan at the N-terminus rather than Asn187 showed decreased effects on isoproterenol-promoted G-protein-dependent signaling, β-arrestin2 recruitment, and receptor internalization. Both N6Q and N15Q showed decreased receptor dimerization, while N187Q did not influence receptor dimerization. As decreased β2 AR homodimer accompanied with reduced efficiency for receptor function, we proposed that the N-glycosylation of β2 AR regulated receptor function by influencing receptor dimerization. To verify this hypothesis, we further paid attention to the residues at the dimerization interface. Studies of Lys60 and Glu338, two residues at the receptor dimerization interface, exhibited that the K60A/E338A showed decreased β2 AR dimerization and its effects on receptor signaling were similar to N6Q and N15Q, which further supported the importance of receptor dimerization for receptor function. This work provides new insights into the relationship among glycosylation, dimerization, and function of GPCRs. Peptide-N-glycosidase F (PNGase F, EC 3.2.2.11); endo-β-N-acetylglucosaminidase A (Endo-A, EC 3.2.1.96). © 2017 Federation of European Biochemical Societies.

  4. Evolution of endothelin receptors in vertebrates.

    Science.gov (United States)

    Braasch, Ingo; Schartl, Manfred

    2014-12-01

    Endothelin receptors are G protein coupled receptors (GPCRs) of the β-group of rhodopsin receptors that bind to endothelin ligands, which are 21 amino acid long peptides derived from longer prepro-endothelin precursors. The most basal Ednr-like GPCR is found outside vertebrates in the cephalochordate amphioxus, but endothelin ligands are only present among vertebrates, including the lineages of jawless vertebrates (lampreys and hagfishes), cartilaginous vertebrates (sharks, rays, and chimaeras), and bony vertebrates (ray-finned fishes and lobe-finned vertebrates including tetrapods). A bona fide endothelin system is thus a vertebrate-specific innovation with important roles for regulating the cardiovascular system, renal and pulmonary processes, as well as for the development of the vertebrate-specific neural crest cell population and its derivatives. Expectedly, dysregulation of endothelin receptors and the endothelin system leads to a multitude of human diseases. Despite the importance of different types of endothelin receptors for vertebrate development and physiology, current knowledge on endothelin ligand-receptor interactions, on the expression of endothelin receptors and their ligands, and on the functional roles of the endothelin system for embryonic development and in adult vertebrates is very much biased towards amniote vertebrates. Recent analyses from a variety of vertebrate lineages, however, have shown that the endothelin system in lineages such as teleost fish and lampreys is more diverse and is divergent from the mammalian endothelin system. This diversity is mainly based on differential evolution of numerous endothelin system components among vertebrate lineages generated by two rounds of whole genome duplication (three in teleosts) during vertebrate evolution. Here we review current understanding of the evolutionary history of the endothelin receptor family in vertebrates supplemented with surveys on the endothelin receptor gene complement of

  5. Regulation of blood pressure by dopamine receptors.

    Science.gov (United States)

    Jose, Pedro A; Eisner, Gilbert M; Felder, Robin A

    2003-01-01

    Dopamine is an important regulator of blood pressure. Its actions on renal hemodynamics, epithelial transport and humoral agents such as aldosterone, catecholamines, endothelin, prolactin, pro-opiomelanocortin, renin and vasopressin place it in central homeostatic position for regulation of extracellular fluid volume and blood pressure. Dopamine also modulates fluid and sodium intake via actions in the central nervous system and gastrointestinal tract, and by regulation of cardiovascular centers that control the functions of the heart, arteries and veins. Abnormalities in dopamine production and receptor function accompany a high percentage of human essential hypertension and several forms of rodent genetic hypertension. Some dopamine receptor genes and their regulators are in loci linked to hypertension in humans and in rodents. Furthermore, single nucleotide polymorphisms (SNPs) of genes that regulate dopamine receptors, alone or via the interaction with SNPs of genes that regulate the renin-angiotensin system, are associated with human essential hypertension. Each of the five dopamine receptor subtypes (D1, D2, D3, D4 and D5) participates in the regulation of blood pressure by mechanisms specific for the subtype. Some receptors (D2 and D5) influence the central and/or peripheral nervous system; others influence epithelial transport and regulate the secretion and receptors of several humoral agents (e.g., the D1, D3 and D4 receptors interact with the renin-angiotensin system). Modifications of the usual actions of the receptor can produce blood pressure changes. In addition, abnormal functioning of these dopamine receptor subtypes impairs their antioxidant function.

  6. Chaperone receptors: guiding proteins to intracellular compartments.

    Science.gov (United States)

    Kriechbaumer, Verena; von Löffelholz, Ottilie; Abell, Ben M

    2012-01-01

    Despite mitochondria and chloroplasts having their own genome, 99% of mitochondrial proteins (Rehling et al., Nat Rev Mol Cell Biol 5:519-530, 2004) and more than 95% of chloroplast proteins (Soll, Curr Opin Plant Biol 5:529-535, 2002) are encoded by nuclear DNA, synthesised in the cytosol and imported post-translationally. Protein targeting to these organelles depends on cytosolic targeting factors, which bind to the precursor, and then interact with membrane receptors to deliver the precursor into a translocase. The molecular chaperones Hsp70 and Hsp90 have been widely implicated in protein targeting to mitochondria and chloroplasts, and receptors capable of recognising these chaperones have been identified at the surface of both these organelles (Schlegel et al., Mol Biol Evol 24:2763-2774, 2007). The role of these chaperone receptors is not fully understood, but they have been shown to increase the efficiency of protein targeting (Young et al., Cell 112:41-50, 2003; Qbadou et al., EMBO J 25:1836-1847, 2006). Whether these receptors contribute to the specificity of targeting is less clear. A class of chaperone receptors bearing tetratricopeptide repeat domains is able to specifically bind the highly conserved C terminus of Hsp70 and/or Hsp90. Interestingly, at least of one these chaperone receptors can be found on each organelle (Schlegel et al., Mol Biol Evol 24:2763-2774, 2007), which suggests a universal role in protein targeting for these chaperone receptors. This review will investigate the role that chaperone receptors play in targeting efficiency and specificity, as well as examining recent in silico approaches to find novel chaperone receptors.

  7. Chemical Sensing by Nonequilibrium Cooperative Receptors

    Science.gov (United States)

    Skoge, Monica; Naqvi, Sahin; Meir, Yigal; Wingreen, Ned S.

    2013-01-01

    Cooperativity arising from local interactions in equilibrium receptor systems provides gain, but does not increase sensory performance, as measured by the signal-to-noise ratio (SNR) due to a fundamental tradeoff between gain and intrinsic noise. Here we allow sensing to be a nonequilibrium process and show that energy dissipation cannot circumvent the fundamental tradeoff, so that the SNR is still optimal for independent receptors. For systems requiring high gain, nonequilibrium 2D-coupled receptors maximize the SNR, revealing a new design principle for biological sensors. PMID:25165963

  8. Receptores de radio monochip para FM

    OpenAIRE

    Miguel López, José María

    2005-01-01

    Este libro aborda de forma estructurada tanto los aspectos de diseño como los de realización de receptores de radio para la banda de FM. Tras unos primeros capítulos dedicados al estudio de las propiedades de la modulación de frecuencia y de los circuitos básicos que configuran un receptor de radio, se desarrolla un minucioso análisis de los circuitos integrados TDA7000/10/21. Paso a paso se muestra cómo diseñar con estos circuitos receptores de FM que, al requerir muy pocos ajustes, puede...

  9. Receptors useful for gas phase chemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Jaworski, Justyn W; Lee, Seung-Wuk; Majumdar, Arunava; Raorane, Digvijay A

    2015-02-17

    The invention provides for a receptor, capable of binding to a target molecule, linked to a hygroscopic polymer or hydrogel; and the use of this receptor in a device for detecting the target molecule in a gaseous and/or liquid phase. The invention also provides for a method for detecting the presence of a target molecule in the gas phase using the device. In particular, the receptor can be a peptide capable of binding a 2,4,6-trinitrotoluene (TNT) or 2,4,-dinitrotoluene (DNT).

  10. GABAA receptor partial agonists and antagonists

    DEFF Research Database (Denmark)

    Krall, Jacob; Balle, Thomas; Krogsgaard-Larsen, Niels;

    2015-01-01

    A high degree of structural heterogeneity of the GABAA receptors (GABAARs) has been revealed and is reflected in multiple receptor subtypes. The subunit composition of GABAAR subtypes is believed to determine their localization relative to the synapses and adapt their functional properties...... to the local temporal pattern of GABA impact, enabling phasic or tonic inhibition. Specific GABAAR antagonists are essential tools for physiological and pharmacological elucidation of the different type of GABAAR inhibition. However, distinct selectivity among the receptor subtypes (populations) has been shown...

  11. Advances in Variations of Estrogen Receptor, Progesterone Receptor and Human Epidermal Growth Factor Receptor-2 Status in Metastatic Breast Cancer

    Institute of Scientific and Technical Information of China (English)

    Yuan Yuan; Zhang Lili

    2013-01-01

    Chemotherapy, endocrine therapy and molecular targeted therapy are vital means in the treatment of metastatic breast cancer (MBC), whose reasonable and standard applications are of great importance to prolong patients’ survival and improve the quality of life. The expressions of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2) present signiifcant differences between primary and metastatic breast cancer. However, these differences may affect the selection of MBC patients for therapeutic strategies and judgment on the prognosis. Hence, the relevant researches on variations of hormone receptors and HER-2 in primary and metastatic breast cancer, discordant causes of ER, PR and HER-2 expression in primary and metastatic lesions and clinical value of biopsy to the metastases are reviewed in the study.

  12. 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.

  13. Nicotinic receptors, memory, and hippocampus.

    Science.gov (United States)

    Kutlu, Munir Gunes; Gould, Thomas J

    2015-01-01

    Nicotinic acetylcholine receptors (nAChRs) modulate the neurobiological processes underlying hippocampal learning and memory. In addition, nicotine's ability to desensitize and upregulate certain nAChRs may alter hippocampus-dependent memory processes. Numerous studies have examined the effects of nicotine on hippocampus-dependent learning, as well as the roles of low- and high-affinity nAChRs in mediating nicotine's effects on hippocampus-dependent learning and memory. These studies suggested that while acute nicotine generally acts as a cognitive enhancer for hippocampus-dependent learning, withdrawal from chronic nicotine results in deficits in hippocampus-dependent memory. Furthermore, these studies demonstrated that low- and high-affinity nAChRs functionally differ in their involvement in nicotine's effects on hippocampus-dependent learning. In the present chapter, we reviewed studies using systemic or local injections of acute or chronic nicotine, nAChR subunit agonists or antagonists; genetically modified mice; and molecular biological techniques to characterize the effects of nicotine on hippocampus-dependent learning.

  14. Endogenous Receptor Agonists: Resolving Inflammation

    Directory of Open Access Journals (Sweden)

    Gerhard Bannenberg

    2007-01-01

    Full Text Available Controlled resolution or the physiologic resolution of a well-orchestrated inflammatory response at the tissue level is essential to return to homeostasis. A comprehensive understanding of the cellular and molecular events that control the termination of acute inflammation is needed in molecular terms given the widely held view that aberrant inflammation underlies many common diseases. This review focuses on recent advances in the understanding of the role of arachidonic acid and ω-3 polyunsaturated fatty acids (PUFA–derived lipid mediators in regulating the resolution of inflammation. Using a functional lipidomic approach employing LC-MS-MS–based informatics, recent studies, reviewed herein, uncovered new families of local-acting chemical mediators actively biosynthesized during the resolution phase from the essential fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. These new families of local chemical mediators are generated endogenously in exudates collected during the resolution phase, and were coined resolvins and protectins because specific members of these novel chemical families control both the duration and magnitude of inflammation in animal models of complex diseases. Recent advances on the biosynthesis, receptors, and actions of these novel anti-inflammatory and proresolving lipid mediators are reviewed with the aim to bring to attention the important role of specific lipid mediators as endogenous agonists in inflammation resolution.

  15. Palmitoylation of Nicotinic Acetylcholine Receptors

    Science.gov (United States)

    Alexander, J. K.; Govind, A. P.; Drisdel, R. C.; Blanton, M. P.; Vallejo, Y.; Lam, T. T.

    2012-01-01

    It is well established that nicotinic acetylcholine receptors (nAChRs) undergo a number of different post-translational modifications, such as disulfide bond formation, glycosylation, and phosphorylation. Recently, our laboratory has developed more sensitive assays of protein palmitoylation that have allowed us and others to detect the palmitoylation of relatively low abundant proteins such as ligand-gated ion channels. Here, we present evidence that palmitoylation is prevalent on many subunits of different nAChR subtypes, both muscle-type nAChRs and the neuronal “α4β2” and “α7” subtypes most abundant in brain. The loss of ligand binding sites that occurs when palmitoylation is blocked with the inhibitor bromopalmitate suggests that palmitoylation of α4β2 and α7 subtypes occurs during subunit assembly and regulates the formation of ligand binding sites. However, additional experiments are needed to test whether nAChR subunit palmitoylation is involved in other aspects of nAChR trafficking or whether palmitoylation regulates nAChR function. Further investigation would be aided by identifying the sites of palmitoylation on the subunits, and here we propose a mass spectrometry strategy for identification of these sites. PMID:19693711

  16. Teleost Chemokines and Their Receptors

    Directory of Open Access Journals (Sweden)

    Steve Bird

    2015-11-01

    Full Text Available Chemokines are a superfamily of cytokines that appeared about 650 million years ago, at the emergence of vertebrates, and are responsible for regulating cell migration under both inflammatory and physiological conditions. The first teleost chemokine gene was reported in rainbow trout in 1998. Since then, numerous chemokine genes have been identified in diverse fish species evidencing the great differences that exist among fish and mammalian chemokines, and within the different fish species, as a consequence of extensive intrachromosomal gene duplications and different infectious experiences. Subsequently, it has only been possible to establish clear homologies with mammalian chemokines in the case of some chemokines with well-conserved homeostatic roles, whereas the functionality of other chemokine genes will have to be independently addressed in each species. Despite this, functional studies have only been undertaken for a few of these chemokine genes. In this review, we describe the current state of knowledge of chemokine biology in teleost fish. We have mainly focused on those species for which more research efforts have been made in this subject, specially zebrafish (Danio rerio, rainbow trout (Oncorhynchus mykiss and catfish (Ictalurus punctatus, outlining which genes have been identified thus far, highlighting the most important aspects of their expression regulation and addressing any known aspects of their biological role in immunity. Finally, we summarise what is known about the chemokine receptors in teleosts and provide some analysis using recently available data to help characterise them more clearly.

  17. Ubiquitylation of the chemokine receptor CCR7 enables efficient receptor recycling and cell migration

    OpenAIRE

    Schäuble, Karin; Hauser, Mark A.; Rippl, Alexandra; Bruderer, Roland; Otero, Carolina; Gröttrup, Marcus; Legler, Daniel F.

    2012-01-01

    The chemokine receptor CCR7 is essential for lymphocyte and dendritic cell homing to secondary lymphoid organs. Owing to the ability to induce directional migration, CCR7 and its ligands CCL19 and CCL21 are pivotal for the regulation of the immune system. Here, we identify a novel function for receptor ubiquitylation in the regulation of the trafficking process of this G-protein-coupled seven transmembrane receptor. We discovered that CCR7 is ubiquitylated in a constitutive, ligand-independen...

  18. GABAB Receptor-Positive Modulators: Enhancement of GABAB Receptor Agonist Effects In Vivo

    OpenAIRE

    Koek, Wouter; France, Charles P.; Cheng, Kejun; Rice, Kenner C.

    2010-01-01

    In vivo effects of GABAB receptor-positive modulators suggest that they have therapeutic potential for treating central nervous system disorders such as anxiety, depression, and drug abuse. Although these effects generally are thought to be mediated by positive modulation of GABAB receptors, such modulation has been examined primarily in vitro. The present study was aimed at further examining the in vivo positive modulatory properties of the GABAB receptor-positive modulators, 2,6-di-tert-but...

  19. 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.

  20. 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.

  1. 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...

  2. Metabotropic glutamate receptor 5 upregulates surface NMDA receptor expression in striatal neurons via CaMKII

    OpenAIRE

    Jin, Dao-Zhong; Xue, Bing; Mao, Li-Min; Wang, John Q

    2015-01-01

    Metabotropic and ionotropic glutamate receptors are closely clustered in postsynaptic membranes and are believed to interact actively with each other to control excitatory synaptic transmission. Metabotropic glutamate receptor 5 (mGluR5), for example, has been well documented to potentiate ionotropic NMDA receptor activity, although underlying mechanisms are poorly understood. In this study, we investigated the role of mGluR5 in regulating trafficking and subcellular distribution of NMDA rece...

  3. RNA editing of the GABAA receptor α3 subunit alters the functional properties of recombinant receptors

    OpenAIRE

    Nimmich, Mitchell L.; Heidelberg, Laura S.; Fisher, Janet L.

    2009-01-01

    RNA editing provides a post-transcriptional mechanism to increase structural heterogeneity of gene products. Recently, the α3 subunit of the GABAA receptors has been shown to undergo RNA editing. As a result, a highly conserved isoleucine residue in the third transmembrane domain is replaced with a methionine. To determine the effect of this structural change on receptor function, we compared the GABA sensitivity, pharmacological properties and macroscopic kinetics of recombinant receptors co...

  4. 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.

  5. 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

  6. G Protein - Coupled Receptors [Receptores Acoplados à Proteína G

    OpenAIRE

    Lucas V. B. Hoelz; Guilherme B. L. de Freitas; Pedro Henrique M. Torres; Tácio Vinício A. Fernandes; Albuquerque, Magaly G.; Joaquim Fernando M. da Silva; Pedro G Pascutti; Ricardo B. de Alencastro

    2013-01-01

    The G protein-coupled receptors (GPCRs) constitute the largest superfamily of proteins encoded by the human genome. These receptors are membrane proteins which share a common structure of seven transmembrane helices and are involved in the cellular signal transduction through activation of heterotrimeric protein (G protein) in intracellular environment. This activation signal, mediated by the agonist binding to the extracellular domain of the receptor, is transmitted into the cell and activat...

  7. ABP: a novel AMPA receptor binding protein.

    Science.gov (United States)

    Srivastava, S; Ziff, E B

    1999-04-30

    We review the cloning of a novel AMPA receptor binding protein (ABP) that interacts with GluR2/3 and is homologous to GRIP. ABP is enriched in the PSD with GluR2 and is localized to the PSD by EM. ABP binds GluR2 via the C-terminal VXI motif through a Class I PDZ interaction. ABP and GRIP can also homo- and heteromultimerize. Thus, ABP and GRIP may be involved in AMPA receptor regulation and localization, by linking it to other cytoskeletal or signaling molecules. We suggest that the ABP/GRIP and PSD-95 families form distinct scaffolds that anchor, respectively, AMPA and NMDA receptors. We are currently investigating proteins that bind ABP and that may regulate the AMPA receptor.

  8. Ecdysteroid receptors in Drosophila melanogaster adult females

    Science.gov (United States)

    Ecdysteroid receptors were identified and partially characterized from total cell extracts of whole animals and dissected tissues from Drosophila melanogaster adult females. Binding studies indicated the presence of two ecdysteroid binding components having high affinity and specificity consistent w...

  9. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results in...

  10. Receptor binding profile of Otilonium bromide.

    Science.gov (United States)

    Evangelista, S; Giachetti, A; Chapelain, B; Neliat, G; Maggi, C A

    1998-08-01

    The interaction of Otilonium bromide (OB) with binding sites for 63 different receptors and ion channels in appropriate preparations has been investigated. Experiments were also performed in rat colon, the preferred tissue for OB 'in vivo' uptake after oral administration. Among the receptors investigated OB binds with sub microM affinity to muscarinic M1, M2, M4, M5 and PAF receptors and with microM affinity to the diltiazem binding site on L type Ca2+ channels. In the rat colon OB shows competitive interaction with the verapamil binding site on L type Ca2+ channels and with muscarinic M2 receptors with IC50 of 1020 and 1220 nM, respectively. These findings provide a molecular rationale to explain the spasmolytic action exerted by OB on intestinal smooth muscle. In particular, a combination of antimuscarinic and Ca2+ channel blocker properties seems to best account for the action of this compound.

  11. Kainate receptors: multiple roles in neuronal plasticity.

    Science.gov (United States)

    Sihra, Talvinder S; Flores, Gonzalo; Rodríguez-Moreno, Antonio

    2014-02-01

    Ionotropic glutamate receptors of the N-methyl-d-aspartate (NMDA)- and AMPA-type, as well as metabotropic glutamate receptors have been extensively invoked in plasticity. Until relatively recently, however, kainate-type receptors (KARs) had been the most elusive to study because of the lack of appropriate pharmacological tools to specifically address their roles. With the development of selective glutamate receptor antagonists, and knockout mice with specific KAR subunits deleted, the functions of KARs in neuromodulation and synaptic transmission, together with their involvement in some types of plasticity, have been extensively probed in the central nervous system. In this review, we summarize the findings related to the roles of KARs in short- and long-term forms of plasticity, primarily in the hippocampus, where KAR function and synaptic plasticity have received avid attention.

  12. Kainate receptor modulation by sodium and chloride.

    Science.gov (United States)

    Plested, Andrew J R

    2011-01-01

    The kainate-type glutamate receptor displays strong modulation by monovalent anions and cations. This modulation is independent of permeation of the ion channel. Instead, structural, computational and biophysical evidence shows that receptor activity is controlled by binding of sodium and chloride ions at sites that stabilize active dimers of glutamate binding domains. Modulation by monovalent ions is a surprisingly general property across ion channel families. However, evidence of a physiological role for ion-dependent effects on glutamate receptors is lacking, perhaps reflecting the adventitious use of ions as structural components of the kainate receptor. "ergo, Hercules, vita humanior sine sale non quit degree […]" "Heaven known, a civilized life is impossible without salt" -Pliny the Elder, Natural History XXXI 88.

  13. Tripodal Receptors for Cation and Anion Sensors

    NARCIS (Netherlands)

    Kuswandi, Bambang; Nuriman,; Verboom, Willem; Reinhoudt, David N.

    2006-01-01

    This review discusses different types of artificial tripodal receptors for the selectiverecognition and sensing of cations and anions. Examples on the relationship between structure andselectivity towards cations and anions are described. Furthermore, their applications as potentiometricion sensing

  14. Brain nuclear receptors and body weight regulation

    Science.gov (United States)

    Neural pathways, especially those in the hypothalamus, integrate multiple nutritional, hormonal, and neural signals, resulting in the coordinated control of body weight balance and glucose homeostasis. Nuclear receptors (NRs) sense changing levels of nutrients and hormones, and therefore play essent...

  15. Agonism and antagonism at the insulin receptor

    DEFF Research Database (Denmark)

    Knudsen, Louise; Hansen, Bo Falck; Jensen, Pia

    2012-01-01

    Insulin can trigger metabolic as well as mitogenic effects, the latter being pharmaceutically undesirable. An understanding of the structure/function relationships between insulin receptor (IR) binding and mitogenic/metabolic signalling would greatly facilitate the preclinical development of new...... insulin analogues. The occurrence of ligand agonism and antagonism is well described for G protein-coupled receptors (GPCRs) and other receptors but in general, with the exception of antibodies, not for receptor tyrosine kinases (RTKs). In the case of the IR, no natural ligand or insulin analogue has been...... shown to exhibit antagonistic properties, with the exception of a crosslinked insulin dimer (B29-B'29). However, synthetic monomeric or dimeric peptides targeting sites 1 or 2 of the IR were shown to be either agonists or antagonists. We found here that the S961 peptide, previously described to be an IR...

  16. NMDA receptor and schizophrenia: a brief history.

    Science.gov (United States)

    Coyle, Joseph T

    2012-09-01

    Although glutamate was first hypothesized to be involved in the pathophysiology of schizophrenia in the 1980s, it was the demonstration that N-methyl-D-aspartate (NMDA) receptor antagonists, the dissociative anesthetics, could replicate the full range of psychotic, negative, cognitive, and physiologic features of schizophrenia in normal subjects that placed the "NMDA receptor hypofunction hypothesis" on firm footing. Additional support came from the demonstration that a variety of agents that enhanced NMDA receptor function at the glycine modulatory site significantly reduced negative symptoms and variably improved cognition in patients with schizophrenia receiving antipsychotic drugs. Finally, persistent blockade of NMDA receptors recreates in experimental animals the critical pathologic features of schizophrenia including downregulation of parvalbumin-positive cortical GABAergic neurons, pyramidal neuron dendritic dysgenesis, and reduced spine density.

  17. Endocrine receptors as targets for new drugs.

    Science.gov (United States)

    Altman, Jennifer

    2006-01-01

    Increasingly detailed knowledge of cellular signalling pathways is providing a sound basis for the development of specific drugs aimed at selected components of the pathways. Many of these targets are receptors and the multitude of hormone receptors makes endocrine functions a rich proving ground for this research. This article reviews a recent meeting (Insights into Receptor Function and New Drug Development Targets; 5th Endocrinology Colloquium of the Fondation Ipsen, Paris, December 5, 2005) where progress in defining suitable targets for drug therapies in the endocrine system and in designing drugs for some of these targets was discussed. Although the family of G-protein-coupled receptors, ubiquitous in the endocrine system, was the central focus, comparisons with other receptor families were made. Many mutations affecting genes coding for receptors or other components of signalling pathways have been found in a wide range of endocrine disorders including obesity, parathyroid malfunction, disorders involving thyroid-stimulating hormone and follicle-stimulating hormone, and tumours in the anterior pituitary, as well as in many types of cancer. These are being used to dissect the normal control mechanisms as well as to provide information for the development of selective drugs. Recently identified mutations that affect the intracellular traffic in newly synthesised receptors open up possibilities of another dimension of cellular regulation of signalling. Both the discovery of hormones such as apelin and its pairing with an 'orphan' receptor, and the unexpected action of a drug against cannabinoid receptors point to further levels of complexity in cardiovascular regulation. Deeper understanding of the evolution of receptor families and of the molecular mechanisms of signal transduction is enabling the design of highly specific agonists and antagonists. Pharmacological intervention is not limited to the ligand-receptor interaction but can extend to inhibition of

  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. Parathyroid hormone receptor recycling: role of receptor dephosphorylation and beta-arrestin.

    Science.gov (United States)

    Chauvin, Stephanie; Bencsik, Margaret; Bambino, Tom; Nissenson, Robert A

    2002-12-01

    The recovery of PTH receptor (PTHR) function after acute homologous receptor desensitization and down-regulation in bone and kidney cells has been attributed to receptor recycling. To determine the role of receptor dephosphorylation in PTHR recycling, we performed morphological and functional assays on human embryonic kidney 293 cells stably expressing wild-type (wt) or mutant PTHRs. Confocal microscopy and ligand binding assays revealed that the wt PTHR is rapidly recycled back to the plasma membrane after removal of the agonist. Receptors that were engineered to either lack the sites of phosphorylation or to resemble constitutively phosphorylated receptors were able to recycle back to the plasma membrane with the same kinetics as the wt PTHR. The PTHR was found to be dephosphorylated by an enzyme apparently distinct from protein phosphatases 1 or 2A. The PTHR and beta-arrestin-2-green fluorescent protein (GFP) were found to stably colocalize during PTHR internalization, whereas after agonist removal and during receptor recycling, the colocalization slowly disappeared. Experiments using phosphorylation-deficient PTHRs and a dominant-negative form of beta-arrestin showed that beta-arrestin does not regulate the efficiency of PTHR recycling. These studies indicate that, unlike many G protein-coupled receptors, PTHR recycling does not require receptor dephosphorylation or its dissociation from beta-arrestin.

  20. Functionally biased signalling properties of 7TM receptors - opportunities for drug development for the ghrelin receptor

    DEFF Research Database (Denmark)

    Sivertsen, B; Holliday, N; Madsen, A N

    2013-01-01

    UNLABELLED: The ghrelin receptor is a 7 transmembrane (7TM) receptor involved in a variety of physiological functions including growth hormone secretion, increased food intake and fat accumulation as well as modulation of reward and cognitive functions. Because of its important role in metabolism...... and energy expenditure, the ghrelin receptor has become an important therapeutic target for drug design and the development of anti-obesity compounds. However, none of the compounds developed so far have been approved for commercial use. Interestingly, the ghrelin receptor is able to signal through several...

  1. Untangling dopamine-adenosine receptor-receptor assembly in experimental parkinsonism in rats

    OpenAIRE

    2014-01-01

    Parkinson’s disease (PD) is a dopaminergic-related pathology in which functioning of the basal ganglia is altered. It has been postulated that a direct receptor-receptor interaction – i.e. of dopamine D2 receptor (D2R) with adenosine A2A receptor (A2AR) (forming D2R-A2AR oligomers) – finely regulates this brain area. Accordingly, elucidating whether the pathology prompts changes to these complexes could provide valuable information for the design of new PD therapies. Here, we first resolved a...

  2. Thyroid hormone receptors regulate adipogenesis and carcinogenesis via crosstalk signaling with peroxisome proliferator-activated receptors

    Science.gov (United States)

    Lu, Changxue; Cheng, Sheue-Yann

    2012-01-01

    Peroxisome proliferator-activated receptors (PPARs) and thyroid hormone receptors (TRs) are members of the nuclear receptor superfamily. They are ligand-dependent transcription factors that interact with their cognate hormone response elements in the promoters to regulate respective target gene expression to modulate cellular functions. While the transcription activity of each is regulated by their respective ligands, recent studies indicate that via multiple mechanisms PPARs and TRs crosstalk to affect diverse biological functions. Here, we review recent advances in the understanding of the molecular mechanisms and biological impact of crosstalk between these two important nuclear receptors, focusing on their roles in adipogenesis and carcinogenesis. PMID:19741045

  3. Thyroid hormone receptors regulate adipogenesis and carcinogenesis via crosstalk signaling with peroxisome proliferator-activated receptors.

    Science.gov (United States)

    Lu, Changxue; Cheng, Sheue-Yann

    2010-03-01

    Peroxisome proliferator-activated receptors (PPARs) and thyroid hormone receptors (TRs) are members of the nuclear receptor superfamily. They are ligand-dependent transcription factors that interact with their cognate hormone response elements in the promoters to regulate respective target gene expression to modulate cellular functions. While the transcription activity of each is regulated by their respective ligands, recent studies indicate that via multiple mechanisms PPARs and TRs crosstalk to affect diverse biological functions. Here, we review recent advances in the understanding of the molecular mechanisms and biological impact of crosstalk between these two important nuclear receptors, focusing on their roles in adipogenesis and carcinogenesis.

  4. Carbamate Insecticides Target Human Melatonin Receptors.

    Science.gov (United States)

    Popovska-Gorevski, Marina; Dubocovich, Margarita L; Rajnarayanan, Rajendram V

    2017-02-20

    Carbaryl (1-naphthyl methylcarbamate) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) are among the most toxic insecticides, implicated in a variety of diseases including diabetes and cancer among others. Using an integrated pharmacoinformatics based screening approach, we have identified these insecticides to be structural mimics of the neurohormone melatonin and were able to bind to the putative melatonin binding sites in MT1 and MT2 melatonin receptors in silico. Carbaryl and carbofuran then were tested for competition with 2-[(125)I]-iodomelatonin (300 pM) binding to hMT1 or hMT2 receptors stably expressed in CHO cells. Carbaryl and carbofuran showed higher affinity for competition with 2-[(125)I]-iodomelatonin binding to the hMT2 compared to the hMT1 melatonin receptor (33 and 35-fold difference, respectively) as predicted by the molecular modeling. In the presence of GTP (100 μM), which decouples the G-protein linked receptors to modulate signaling, the apparent efficacy of carbaryl and carbofuran for 2-[(125)I]-iodomelatonin binding for the hMT1 melatonin receptor was not affected but significantly decreased for the hMT2 melatonin receptor compatible with receptor antagonist/inverse agonist and agonist efficacy, respectively. Altogether, our data points to a potentially new mechanism through which carbamate insecticides carbaryl and carbofuran could impact human health by altering the homeostatic balance of key regulatory processes by directly binding to melatonin receptors.

  5. Targeting Discoidin Domain Receptors in Prostate Cancer

    Science.gov (United States)

    2016-08-01

    1 AWARD NUMBER: W81XWH-15-1-0226 TITLE: Targeting Discoidin Domain Receptors in Prostate Cancer PRINCIPAL INVESTIGATOR: Dr. Rafael Fridman...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-15-1-0226 Targeting Discoidin Domain Receptors in Prostate Cancer 5b. GRANT NUMBER W81XWH-15...DDRs in prostate cancer . During the first funding period, we conducted immunohistochemical studies by staining a 200 case Grade/Stage tissue

  6. Moth sex pheromone receptors and deceitful parapheromones.

    Directory of Open Access Journals (Sweden)

    Pingxi Xu

    Full Text Available The insect's olfactory system is so selective that male moths, for example, can discriminate female-produced sex pheromones from compounds with minimal structural modifications. Yet, there is an exception for this "lock-and-key" tight selectivity. Formate analogs can be used as replacement for less chemically stable, long-chain aldehyde pheromones, because male moths respond physiologically and behaviorally to these parapheromones. However, it remained hitherto unknown how formate analogs interact with aldehyde-sensitive odorant receptors (ORs. Neuronal responses to semiochemicals were investigated with single sensillum recordings. Odorant receptors (ORs were cloned using degenerate primers, and tested with the Xenopus oocyte expression system. Quality, relative quantity, and purity of samples were evaluated by gas chromatography and gas chromatography-mass spectrometry. We identified olfactory receptor neurons (ORNs housed in trichoid sensilla on the antennae of male navel orangeworm that responded equally to the main constituent of the sex pheromone, (11Z,13Z-hexadecadienal (Z11Z13-16Ald, and its formate analog, (9Z,11Z-tetradecen-1-yl formate (Z9Z11-14OFor. We cloned an odorant receptor co-receptor (Orco and aldehyde-sensitive ORs from the navel orangeworm, one of which (AtraOR1 was expressed specifically in male antennae. AtraOR1•AtraOrco-expressing oocytes responded mainly to Z11Z13-16Ald, with moderate sensitivity to another component of the sex pheromone, (11Z,13Z-hexadecadien-1-ol. Surprisingly, this receptor was more sensitive to the related formate than to the natural sex pheromone. A pheromone receptor from Heliothis virescens, HR13 ( = HvirOR13 showed a similar profile, with stronger responses elicited by a formate analog than to the natural sex pheromone, (11Z-hexadecenal thus suggesting this might be a common feature of moth pheromone receptors.

  7. (pro)renin receptor: A stable molecule

    OpenAIRE

    Wiwanitkit, Viroj

    2011-01-01

    Background: Basically, (pro)renin acts via a specific receptor, (pro)renin receptor (PRR) binding between renin and prorenin, its inactive proenzyme form. The study on the molecular level of PRR can give useful knowledge to help understand many renal disorders. Method: Here, the author focuses on the stability of the PRR molecule. The mutation prone positions within the PRR molecule was assessed using standard reference technique. Result: The study showed there is no identified mutation prone...

  8. Kinin receptors in skin wound healing.

    Science.gov (United States)

    Soley, Bruna da Silva; Morais, Rafael Leite Tavares de; Pesquero, João Bosco; Bader, Michael; Otuki, Michel Fleith; Cabrini, Daniela Almeida

    2016-05-01

    Wound healing is a complex and dynamic process that includes 3 different phases: inflammation, proliferation, and remodeling. Kinins are vasoactive peptides released after tissue injury, and are directly involved in the development and maintenance of inflammatory processes, and their actions are mediated by the activation of receptors called B1 and B2. We aimed to evaluate the involvement of kinin receptors in the skin healing process. Knockout mice for kinin receptors (KOB1, KOB2 and KOB1B2) and wild type controls (WT) were subjected to a skin excision model, and tissue repair process was evaluated during different phases of wound healing. In knockout animals for kinin receptors differences were observed in the resolution period of injury exceeding 17 days for the total closure of wounds. The absence of kinin receptors promotes a significant reduction in infiltration of polymorphonuclear cells on day 2 of the inflammatory phase. Already at the late stage of this phase (3 days) there was a negative influence on the infiltration of polymorphonuclear and mononuclear cells at the site of injury in comparison to WT. Collagen was significantly diminished in tissue of KOB1, KOB2 and KOB1B2 from day two to the end of the healing process. Moreover, wound tissue from KOB2 and KOB1B2, but not KOB1, presented impaired parameters of re-epitheliazation, reduced proliferation of cells (PCNA immunostaining), and a lower number of myofibroblasts (α-SMA immunostaining). These data reveal the involvement of kinin receptors in processes of skin repair. Both kinin receptors participate especially during the inflammatory phase, while B2 receptors seem to be more relevant in the quality of the wound scar. Thus, a better understanding of the contribution of kinins to skin wound healing may reveal novel options for therapy. Copyright © 2016. Published by Elsevier Ireland Ltd.

  9. The effects of stiripentol on GABAA receptors

    OpenAIRE

    Fisher, Janet L.

    2011-01-01

    The anti-convulsant Stiripentol (Diacomit™) has been shown to have a positive impact on control of seizures for many patients with Dravet Syndrome. As with most anti-epileptic drugs, stiripentol has multiple mechanisms of action. Its direct anti-convulsant activity is likely due to enhancement of inhibitory, GABAergic neurotransmission. Stiripentol was shown to increase the activity of both neuronal and recombinant GABAA receptors at clinically relevant concentrations. At recombinant receptor...

  10. Selectivity of Odorant Receptors in Insects

    Science.gov (United States)

    2012-07-13

    repellents do not elicit evolutionary adaptive behaviors in mosquitoes , but rather disrupt the final stages of host attraction (Figure 1B). It is...Dickens, J. C. (2010). Insect repellents : mod- ulators of mosquito odorant receptor activity. PLoS ONE 5, e12138. doi: 10.1371/journal.pone. 0012138...Multiple activities of insect repellents on odorant receptors in mosquitoes . Med. Vet. Entomol. 25, 436–444. Bohbot, J. D., Jones, P. L., Wang, G

  11. G Protein-Coupled Receptors in Cancer

    OpenAIRE

    Rachel Bar-Shavit; Myriam Maoz; Arun Kancharla; Jeetendra Kumar Nag; Daniel Agranovich; Sorina Grisaru-Granovsky; Beatrice Uziely

    2016-01-01

    Despite the fact that G protein-coupled receptors (GPCRs) are the largest signal-conveying receptor family and mediate many physiological processes, their role in tumor biology is underappreciated. Numerous lines of evidence now associate GPCRs and their downstream signaling targets in cancer growth and development. Indeed, GPCRs control many features of tumorigenesis, including immune cell-mediated functions, proliferation, invasion and survival at the secondary site. Technological advances ...

  12. New Selective Estrogen and Androgen Receptor Modulators

    Science.gov (United States)

    Clarke, Bart L.; Khosla, Sundeep

    2010-01-01

    Purpose of Review The present review focuses on the most significant recent findings regarding selective estrogen receptor modulators (SERMs) and selective androgen receptor modulators (SARMs). SERMs, which interact with estrogen receptor (ER)-α and ER-β in multiple tissues, continue to generate clinical interest in potential applications in as many disorders as the tissues in which the two known receptors are found. SARMs have been demonstrated to have fewer clinical applications to date, but continue to be investigated for use in multiple disorders in which androgen receptor (AR) modulation is likely to be important. Both types of compounds hold great promise for therapeutic use in multiple hormonal disorders involving tissue-specific effects mediated by estrogen or androgen receptors. Recent Findings While SERMs have been available for clinical use for 50 years, recent investigation has focused on large randomized clinical trials for newer indications of older agents, or smaller clinical trials of newer agents with improved clinical activity and reduced side effects in specific tissues. In particular, the large, prospective, randomized, controlled, multi-year STAR and RUTH clinical trials have recently shown interesting similarities and differences between tamoxifen and raloxifene in estrogen-responsive tissues. Lasofoxifene and arzoxifene are two newer SERMs that have recently been demonstrated to improve bone mineral density and lower serum cholesterol values compared to older SERMs in smaller clinical trials. SARMs are a newer category of drug still being investigated mostly at the basic and preclinical level, with fewer clinical trials available for review. SARMs are currently being investigated mostly for use in prostate cancer at different stages, but hold promise for multiple other applications. Summary Recent clinical trials indicate that selective estrogen receptor modulators are useful in treatment of disorders of bone and mineral metabolism and

  13. Agonist discrimination between AMPA receptor subtypes

    DEFF Research Database (Denmark)

    Coquelle, T; Christensen, J K; Banke, T G

    2000-01-01

    The lack of subtype-selective compounds for AMPA receptors (AMPA-R) led us to search for compounds with such selectivity. Homoibotenic acid analogues were investigated at recombinant GluR1o, GluR2o(R), GluR3o and GluR1o + 3o receptors expressed in Sf9 insect cells and affinities determined in [3H...

  14. Dopamine receptors - physiological understanding to therapeutic intervention potential

    NARCIS (Netherlands)

    Emilien, G; Maloteaux, JM; Hoogenberg, K; Cragg, S

    1999-01-01

    There are two families of dopamine (DA) receptors, called D(1) and D(2), respectively. The D(1) family consists of D(1)- and D(5)-receptor subtypes and the D(2) family consists of D(2)-, D(3)-, and D(4)-receptor subtypes. The amino acid sequences of these receptors show that they all belong to a lar

  15. In vivo opioid receptor heteromerization: where do we stand?

    OpenAIRE

    Massotte, D

    2014-01-01

    Opioid receptors are highly homologous GPCRs that modulate brain function at all levels of neural integration, including autonomous, sensory, emotional and cognitive processing. Opioid receptors functionally interact in vivo, but the underlying mechanisms involving direct receptor–receptor interactions, affecting signalling pathways or engaging different neuronal circuits, remain unsolved. Heteromer formation through direct physical interaction between two opioid receptors or between an opioi...

  16. Dopamine receptors - physiological understanding to therapeutic intervention potential

    NARCIS (Netherlands)

    Emilien, G; Maloteaux, JM; Hoogenberg, K; Cragg, S

    1999-01-01

    There are two families of dopamine (DA) receptors, called D(1) and D(2), respectively. The D(1) family consists of D(1)- and D(5)-receptor subtypes and the D(2) family consists of D(2)-, D(3)-, and D(4)-receptor subtypes. The amino acid sequences of these receptors show that they all belong to a lar

  17. Targeting the TAM Receptors in Leukemia

    Directory of Open Access Journals (Sweden)

    Madeline G. Huey

    2016-11-01

    Full Text Available Targeted inhibition of members of the TAM (TYRO-3, AXL, MERTK family of receptor tyrosine kinases has recently been investigated as a novel strategy for treatment of hematologic malignancies. The physiologic functions of the TAM receptors in innate immune control, natural killer (NK cell differentiation, efferocytosis, clearance of apoptotic debris, and hemostasis have previously been described and more recent data implicate TAM kinases as important regulators of erythropoiesis and megakaryopoiesis. The TAM receptors are aberrantly or ectopically expressed in many hematologic malignancies including acute myeloid leukemia, B- and T-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and multiple myeloma. TAM receptors contribute to leukemic phenotypes through activation of pro-survival signaling pathways and interplay with other oncogenic proteins such as FLT3, LYN, and FGFR3. The TAM receptors also contribute to resistance to both cytotoxic chemotherapeutics and targeted agents, making them attractive therapeutic targets. A number of translational strategies for TAM inhibition are in development, including small molecule inhibitors, ligand traps, and monoclonal antibodies. Emerging areas of research include modulation of TAM receptors to enhance anti-tumor immunity, potential roles for TYRO-3 in leukemogenesis, and the function of the bone marrow microenvironment in mediating resistance to TAM inhibition.

  18. Melanocortin Receptors, Melanotropic Peptides and Penile Erection

    Science.gov (United States)

    King, Stephen H.; Mayorov, Alexander V.; Balse-Srinivasan, Preeti; Hruby, Victor J.; Vanderah, Todd W.; Wessells, Hunter

    2009-01-01

    Penile erection is a complex physiologic event resulting from the interactions of the nervous system on a highly specialized vascular organ. Activation of central nervous system melanocortinergic (MC) receptors with either endogenous or synthetic melanotropic ligands may initiate and/or facilitate spontaneous penile erection. While the CNS contains principally the MC3 and MC4 receptor subtypes, there is conflicting data as to which receptor mediates erection. Although the MC4R is emerging as the principle effector of MC induced erection, the role of the MC3R is poorly understood. Manipulation of each receptor subtype with newly synthesized receptor specific agonists and antagonists, as well as knockout mice, has elucidated their individual contributions. Novel data from our laboratories suggests that antagonism of forebrain MC3R may enhance melanocortin-induced erections. Furthermore, melanocortin agents may interact with better-studied systems such as oxytocinergic pathways at the hypothalamic, brainstem or spinal level. Current therapies for erectile dysfunction target end organ vascular tissue. Manipulation of MC receptors may provide an alternative, centrally mediated therapeutic approach for erectile and other sexual dysfunctions. The non-specific “superpotent” MC agonist, PT-141, which is the carboxylate derivative of MT-II, has reached phase II human trials. Through their centrally mediated activity, melanocortin agonists have potential to treat erectile dysfunction as well as possible applications to the unmet medical needs of decreased sexual motivation and loss of libido. PMID:17584130

  19. Adenosine receptor targeting in health and disease.

    Science.gov (United States)

    Gessi, Stefania; Merighi, Stefania; Fazzi, Debora; Stefanelli, Angela; Varani, Katia; Borea, Pier Andrea

    2011-12-01

    The adenosine receptors A(1), A(2A), A(2B) and A(3) are important and ubiquitous mediators of cellular signaling that play vital roles in protecting tissues and organs from damage. In particular, adenosine triggers tissue protection and repair by different receptor-mediated mechanisms, including increasing the oxygen supply:demand ratio, pre-conditioning, anti-inflammatory effects and the stimulation of angiogenesis. The state of the art of the role of adenosine receptors which have been proposed as targets for drug design and discovery, in health and disease, and an overview of the ligands for these receptors in clinical development. Selective ligands of A(1), A(2A), A(2B) and A(3) adenosine receptors are likely to find applications in the treatment of pain, ischemic conditions, glaucoma, asthma, arthritis, cancer and other disorders in which inflammation is a feature. The aim of this review is to provide an overview of the present knowledge regarding the role of these adenosine receptors in health and disease.

  20. Regulation of Immune Cells by Eicosanoid Receptors

    Directory of Open Access Journals (Sweden)

    Nancy D. Kim

    2007-01-01

    Full Text Available Eicosanoids are potent, bioactive, lipid mediators that regulate important components of the immune response, including defense against infection, ischemia, and injury, as well as instigating and perpetuating autoimmune and inflammatory conditions. Although these lipids have numerous effects on diverse cell types and organs, a greater understanding of their specific effects on key players of the immune system has been gained in recent years through the characterization of individual eicosanoid receptors, the identification and development of specific receptor agonists and inhibitors, and the generation of mice genetically deficient in various eicosanoid receptors. In this review, we will focus on the receptors for prostaglandin D2, DP1 and DP2/CRTH2; the receptors for leukotriene B4, BLT1 and BLT2; and the receptors for the cysteinyl leukotrienes, CysLT1 and CysLT2, by examining their specific effects on leukocyte subpopulations, and how they may act in concert towards the development of immune and inflammatory responses.