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Sample records for hormone-related peptide receptor

  1. Invertebrate Gonadotropin-Releasing Hormone-Related Peptides and Their Receptors: An Update

    Directory of Open Access Journals (Sweden)

    Tsubasa Sakai

    2017-09-01

    Full Text Available Gonadotropin-releasing hormones (GnRHs play pivotal roles in reproductive functions via the hypothalamus, pituitary, and gonad axis, namely, HPG axis in vertebrates. GnRHs and their receptors (GnRHRs are likely to be conserved in invertebrate deuterostomes and lophotrochozoans. All vertebrate and urochordate GnRHs are composed of 10 amino acids, whereas protostome, echinoderm, and amphioxus GnRH-like peptides are 11- or 12-residue peptide containing two amino acids after an N-terminal pyro-Glu. In urochordates, Halocynthia roretzi GnRH gene encodes two GnRH peptide sequences, whereas two GnRH genes encode three different GnRH peptides in Ciona intestinalis. These findings indicate the species-specific diversification of GnRHs. Intriguingly, the major signaling pathway for GnRHRs is intracellular Ca2+ mobilization in chordates, echinoderms, and protostomes, whereas Ciona GnRHRs (Ci-GnRHRs are endowed with multiple GnRHergic cAMP production pathways in a ligand-selective manner. Moreover, the ligand-specific modulation of signal transduction via heterodimerization among Ci-GnRHR paralogs suggests the species-specific development of fine-tuning of gonadal functions in ascidians. Echinoderm GnRH-like peptides show high sequence differences compared to those of protostome counterparts, leading to the difficulty in classification of peptides and receptors. These findings also show both the diversity and conservation of GnRH signaling systems in invertebrates. The lack of the HPG axis in invertebrates indicates that biological functions of GnRHs are not release of gonadotropins in current invertebrates and common ancestors of vertebrates and invertebrates. To date, authentic or putative GnRHRs have been characterized from various echinoderms and protostomes as well as chordates and the mRNAs have been found to be distributed not only reproductive organs but also other tissues. Collectively, these findings further support the notion that invertebrate Gn

  2. Actions of parathyroid hormone related peptide in mouse parietal endoderm formation

    NARCIS (Netherlands)

    Veltmaat, J.M.

    2001-01-01

    Summary Since about a decade, several reports have strongly suggested a role for parathyroid hormone related peptide (PTHrP) in the formation of parietal endoderm (PE) in the mouse embryo. This thesis is aimed first at elucidating the biological significance of parathyroid hormone related peptide

  3. Parathyroid Hormone-Related Peptide Elicits Peripheral TRPV1-dependent Mechanical Hypersensitivity

    Science.gov (United States)

    Shepherd, Andrew J.; Mickle, Aaron D.; Kadunganattil, Suraj; Hu, Hongzhen; Mohapatra, Durga P.

    2018-01-01

    Bone metastasis in breast, prostate and lung cancers often leads to chronic pain, which is poorly managed by existing analgesics. The neurobiological mechanisms that underlie chronic pain associated with bone-metastasized cancers are not well understood, but sensitization of peripheral nociceptors by tumor microenvironment factors has been demonstrated to be important. Parathyroid hormone-related peptide (PTHrP) is highly expressed in bone-metastasized breast and prostate cancers, and is critical to growth and proliferation of these tumors in the bone tumor microenvironment. Previous studies have suggested that PTHrP could sensitize nociceptive sensory neurons, resulting in peripheral pain hypersensitivity. In this study, we found that PTHrP induces both heat and mechanical hypersensitivity, that are dependent on the pain-transducing transient receptor potential channel family vanilloid, member-1 (TRPV1), but not the mechano-transducing TRPV4 and TRPA1 ion channels. Functional ratiometric Ca2+ imaging and voltage-clamp electrophysiological analysis of cultured mouse DRG neurons show significant potentiation of TRPV1, but not TRPA1 or TRPV4 channel activation by PTHrP. Interestingly, PTHrP exposure led to the slow and sustained activation of TRPV1, in the absence of any exogenous channel agonist, and is dependent on the expression of the type-1 parathyroid hormone receptor (PTH1), as well as on downstream phosphorylation of the channel by protein kinase C (PKC). Accordingly, local administration of specific small-molecule antagonists of TRPV1 to mouse hindpaws after the development of PTHrP-induced mechanical hypersensitivity led to its significant attenuation. Collectively, our findings suggest that PTHrP/PTH1-mediated flow activation of TRPV1 channel contributes at least in part to the development and maintenance of peripheral mechanical pain hypersensitivity, and could therefore constitute a mechanism for nociceptor sensitization in the context of metastatic bone

  4. Parathyroid hormone-related peptide is a downstream target for ras and src activation.

    Science.gov (United States)

    Li, X; Drucker, D J

    1994-03-04

    Neoplastic transformation may be associated with the development of paraneoplastic syndromes that complicate the management of patients with malignant disease. One of these syndromes, humoral hypercalcemia of malignancy, has been shown to be attributable to increased secretion of a parathyroid hormone-related peptide (PTHrP). The gene encoding PTHrP is expressed at low levels in a growth factor-dependent manner in normal tissues, and the mechanisms underlying selective tumor-associated induction of PTHrP gene expression remain unclear. Here we show that cellular transformation by the EJ-Ha-ras and v-src oncogenes is associated with a marked increase in PTHrP gene expression. Ha-ras- and v-src-transfected NRK 49F cells and ras-transfected RCB 2.2 cell lines secreted increased amounts of immunoreactive PTHrP. Northern blot analysis also demonstrated increased levels of PTHrP mRNA transcripts in oncogene-transfected stable cell lines. No significant change in the half-life of PTHrP mRNA transcripts was detected in Ha-ras- and v-src-transformed cells. In contrast, nuclear run-on assays demonstrated an increased rate of PTHrP gene transcription in oncogene-transformed cells. These observations demonstrate that the gene encoding PTHrP is a downstream target for ras and src, potentially providing a molecular basis for understanding the activation of PTHrP gene expression in malignancy-associated hypercalcemia.

  5. Parathyroid hormone-related peptide plasma concentrations in patients on hemodialysis

    DEFF Research Database (Denmark)

    Nordholm, Anders; Rix, M.; Olgaard, K.

    2014-01-01

    /paracrine function in the parathyroids, but it is still uncertain if PTHrP is a secretory product of the gland and thereby possess endocrine actions. In cells of severe adenomatous secondary hyperparathyroidism PTHrP and PTH have been found to be co-localized in the same secretory granules. PTH and PTHrP act through......BACKGROUND: Uremic patients develop hyperplasia of the parathyroid glands due to disturbances in the mineral metabolism. The hyperplastic parathyroids are associated with significant expression of parathyroid hormone (PTH)-related peptide (PTHrP). PTHrP has been shown to have an autocrine...... not derive from the uremic hyperplastic parathyroid glands...

  6. Humoral Hypercalcemia of Malignancy with a Parathyroid Hormone-Related Peptide-Secreting Intrahepatic Cholangiocarcinoma Accompanied by a Gastric Cancer

    Directory of Open Access Journals (Sweden)

    Katsushi Takeda

    2017-01-01

    Full Text Available Humoral hypercalcemia of malignancy (HHM is caused by the oversecretion of parathyroid hormone-related peptide (PTHrP from malignant tumors. Although any tumor may cause HHM, that induced by intrahepatic cholangiocarcinoma (ICC or gastric cancer (GC is rare. We report here a 74-year-old male who displayed HHM with both ICC and GC and showed an elevated serum PTHrP level. Treatment of the hypercalcemia with saline, furosemide, elcatonin, and zoledronic acid corrected his serum calcium level and improved symptoms. Because treatment of ICC should precede that of GC, we chose chemotherapy with cisplatin (CDDP and gemcitabine (GEM. Chemotherapy reduced the size of the ICC and decreased the serum PTHrP level. One year after diagnosis, the patient was alive in the face of a poor prognosis for an ICC that produced PTHrP. Immunohistochemical staining for PTHrP was positive for the ICC and negative for the GC, leading us to believe that the cause of the HHM was a PTHrP-secreting ICC. In conclusion, immunohistochemical staining for PTHrP may be useful in discovering the cause of HHM in the case of two cancers accompanied by an elevated serum PHTrP level. Chemotherapy with CDDP and GEM may be the most appropriate treatment for a PTHrP-secreting ICC.

  7. Effects of abaloparatide, a human parathyroid hormone-related peptide analog, on bone mineral density in postmenopausal women with osteoporosis.

    Science.gov (United States)

    Leder, Benjamin Z; O'Dea, Louis St L; Zanchetta, José R; Kumar, Prasana; Banks, Kathleen; McKay, Kathleen; Lyttle, C Richard; Hattersley, Gary

    2015-02-01

    Abaloparatide is a novel synthetic peptide analog of parathyroid hormone-related protein (PTHrP) that is currently being developed as a potential anabolic agent in the treatment of postmenopausal osteoporosis. This study sought to assess the effects of abaloparatide on bone mineral density (BMD) at the lumbar spine, total hip, and femoral neck in postmenopausal women with osteoporosis. Multi-center, multi-national, double-blind placebo controlled trial in which postmenopausal women were randomly assigned to receive 24 weeks of treatment with daily sc injections of placebo, abaloparatide, 20, 40, or 80 μg, or teriparatide, 20 μg. A 24-week extension was also performed in a subset of subjects. Postmenopausal women with osteoporosis (n = 222). BMD by dual-x-ray absorptiometry and biochemical markers of bone turnover. At 24 weeks, lumbar spine BMD increased by 2.9, 5.2, and 6.7% in the abaloparatide, 20-, 40-, and 80-μg groups, respectively, and 5.5% in the teriparatide group. The increases in the 40- and 80-μg abaloparatide groups and the teriparatide group were significantly greater than placebo (1.6%). Femoral neck BMD increased by 2.7, 2.2, and 3.1% in abaloparatide, 20-, 40-, and 80-μg groups, respectively, and 1.1% in the teriparatide group. The increase in femoral neck BMD with abaloparatide, 80 μg was significantly greater than placebo (0.8%). Total hip BMD increased by 1.4, 2.0, and 2.6% in the abaloparatide, 20-, 40-, and 80-μg groups, respectively. The total hip increases in the 40- and 80-μg abaloparatide groups were greater than both placebo (0.4%) and teriparatide (0.5%). Compared with placebo, 24 weeks of daily sc abaloparatide increases BMD of the lumbar spine, femoral neck, and total hip in a dose-dependent fashion. Moreover, the abaloparatide-induced BMD increases at the total hip are greater than with the marketed dose of teriparatide. These results support the further investigation of abaloparatide as an anabolic therapy in postmenopausal

  8. Switching of G-protein Usage by the Calcium-sensing Receptor Reverses Its Effect on Parathyroid Hormone-related Protein Secretion in Normal Versus Malignant Breast Cells*

    OpenAIRE

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Zawalich, Walter; Wysolmerski, John

    2008-01-01

    The calcium-sensing receptor (CaR) is a G-protein-coupled receptor that signals in response to extracellular calcium and regulates parathyroid hormone secretion. The CaR is also expressed on normal mammary epithelial cells (MMECs), where it has been shown to inhibit secretion of parathyroid hormone-related protein (PTHrP) and participate in the regulation of calcium and bone metabolism during lactation. In contrast to normal breast cells, the CaR has been reported to s...

  9. Treatment with N- and C-Terminal Peptides of Parathyroid Hormone-Related Protein Partly Compensate the Skeletal Abnormalities in IGF-I Deficient Mice

    Science.gov (United States)

    Portal-Núñez, Sergio; Murillo-Cuesta, Silvia; Lozano, Daniel; Cediel, Rafael; Esbrit, Pedro

    2014-01-01

    Insulin-like growth factor-I (IGF-I) deficiency causes growth delay, and IGF-I has been shown to partially mediate bone anabolism by parathyroid hormone (PTH). PTH-related protein (PTHrP) is abundant in bone, and has osteogenic features by poorly defined mechanisms. We here examined the capacity of PTHrP (1–36) and PTHrP (107–111) (osteostatin) to reverse the skeletal alterations associated with IGF-I deficiency. Igf1-null mice and their wild type littermates were treated with each PTHrP peptide (80 µg/Kg/every other day/2 weeks; 2 males and 4 females for each genotype) or saline vehicle (3 males and 3 females for each genotype). We found that treatment with either PTHrP peptide ameliorated trabecular structure in the femur in both genotypes. However, these peptides were ineffective in normalizing the altered cortical structure at this bone site in Igf1-null mice. An aberrant gene expression of factors associated with osteoblast differentiation and function, namely runx2, osteoprotegerin/receptor activator of NF-κB ligand ratio, Wnt3a, cyclin D1, connexin 43, catalase and Gadd45, as well as in osteocyte sclerostin, was found in the long bones of Igf1-null mice. These mice also displayed a lower amount of trabecular osteoblasts and osteoclasts in the tibial metaphysis than those in wild type mice. These alterations in Igf1-null mice were only partially corrected by each PTHrP peptide treatment. The skeletal expression of Igf2, Igf1 receptor and Irs2 was increased in Igf1-null mice, and this compensatory profile was further improved by treatment with each PTHrP peptide related to ERK1/2 and FoxM1 activation. In vitro, PTHrP (1–36) and osteostatin were effective in promoting bone marrow stromal cell mineralization in normal mice but not in IGF-I-deficient mice. Collectively, these findings indicate that PTHrP (1–36) and osteostatin can exert several osteogenic actions even in the absence of IGF-I in the mouse bone. PMID:24503961

  10. Crystallization of the receptor-binding domain of parathyroid hormone-related protein in complex with a neutralizing monoclonal antibody Fab fragment

    Energy Technology Data Exchange (ETDEWEB)

    McKinstry, William J.; Polekhina, Galina; Diefenbach-Jagger, Hannelore; Sato, Koh; Onuma, Etsuro; Gillespie, Matthew T.; Martin, Thomas J.; Parker, Michael W.; (SVIMR-A); (Chugai); (Melbourne)

    2009-04-01

    Parathyroid hormone-related protein (PTHrP) plays an important role in regulating embryonic skeletal development and is abnormally regulated in the pathogenesis of skeletal complications observed with many cancers and osteoporosis. It exerts its action through binding to a G-protein-coupled seven-transmembrane cell-surface receptor (GPCR). Structurally, GPCRs are very difficult to study by X-ray crystallography. In this study, a monoclonal antibody Fab fragment which recognizes the same region of PTHrP as its receptor, PTH1R, was used to aid in the crystallization of PTHrP. The resultant protein complex was crystallized using the hanging-drop vapour-diffusion method with polyethylene glycol as a precipitant. The crystals belonged to the orthorhombic space group P2{sub 1}2{sub 1}2, with unit-cell parameters a = 72.6, b = 96.3, c = 88.5 {angstrom}, and diffracted to 2.0 {angstrom} resolution using synchrotron radiation. The crystal structure will shed light on the nature of the key residues of PTHrP that interact with the antibody and will provide insights into how the antibody is able to discriminate between PTHrP and the related molecule parathyroid homone.

  11. Associations of hormone-related factors with breast cancer risk according to hormone receptor status among white and African American women.

    Science.gov (United States)

    Cui, Yong; Deming-Halverson, Sandra L; Shrubsole, Martha J; Beeghly-Fadiel, Alicia; Fair, Alecia M; Sanderson, Maureen; Shu, Xiao-Ou; Kelley, Mark C; Zheng, Wei

    2014-12-01

    Causes of racial disparities in breast cancer incidence and mortality between white and African American women remain unclear. This study evaluated associations of menstrual and reproductive factors with breast cancer risk by race and cancer subtypes. Included in the study were 1866 breast cancer cases and 2306 controls recruited in the Nashville Breast Health Study, a population-based case-control study. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). African American women were more likely to have estrogen receptor-negative (ER(-)), progesterone receptor-negative (PR(-)), and triple-negative (ER(-)PR(-)HER2(-)) breast cancer than white women. Age at menarche (≥ 14 years) and multiparity (≥ 3 live births) were inversely associated with ER(+) tumors only, whereas late age at first live birth (> 30 years) and nulliparity were associated with elevated risk; such associations were predominantly seen in white women (OR = 0.70, 95% CI = 0.55-0.88; OR = 0.72, 95% CI = 0.56-0.92; OR = 1.42, 95% CI = 1.13-1.79; OR = 1.32, 95% CI = 1.06-1.63, respectively). Age at menopause between 47 and 51 years was associated with elevated risk of ER(-) tumors in both white and African American women. Among women who had natural menopause, positive association between ever-use of hormone replacement therapy and breast cancer risk was seen in white women only (OR = 1.39, 95% CI = 1.03-1.87). This study suggests that certain hormone-related factors are differentially associated with risk of breast cancer subtypes, and these associations also differ by race. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Gastrin Receptor-Avid Peptide Conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Timothy J. (Columbia, MO); Volkert, Wynn A. (Columbia, MO); Li, Ning (Baltimore, MD); Sieckman, Gary (Ashland, MO); Higginbotham, Chrys-Ann (Columbia, MO)

    2005-07-26

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  13. Gastrin receptor-avid peptide conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Timothy J.; Volkert, Wynn A.; Sieckman, Gary; Smith, Charles J.; Gali, Hariprasad

    2006-06-13

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a-moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  14. Gastrin receptor-avid peptide conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Timothy J.; Volkert, Wynn A.; Li, Ning; Sieckman, Gary; Higginbotham, Chrys-Ann

    2006-12-12

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  15. Bombesin and Neurotensin Receptor Targeting Using Radiolabeled Peptide Analogs

    NARCIS (Netherlands)

    M. de Visser (Monique)

    2007-01-01

    textabstractSomatostatin receptor-targeting peptides are widely used for imaging and therapy of neuroendocrine tumors. Peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumor patients with radiolabeled somatostatin analogs has resulted in symptomatic improvement, prolonged survival and

  16. Formyl peptide receptor chimeras define domains involved in ligand binding.

    Science.gov (United States)

    Perez, H D; Holmes, R; Vilander, L R; Adams, R R; Manzana, W; Jolley, D; Andrews, W H

    1993-02-05

    We have begun to study the structural requirements for the binding of formyl peptides to their specific receptors. As an initial approach, we constructed C5a-formyl peptide receptor chimeras. Unique (and identical) restriction sites were introduced within the transmembrane domains of these receptors that allowed for the exchange of specific areas. Four types of chimeric receptors were generated. 1) The C5a receptor was progressively substituted by the formyl peptide receptor. 2) The formyl peptide receptor was progressively substituted by the C5a receptor. 3) Specific domains of the C5a receptor were substituted by the corresponding domain of the formyl peptide receptor. 4) Specific domains of the formyl peptide receptor were replaced by the same corresponding domain of the C5a receptor. Wild type and chimeric receptors were transfected into COS 7 cells and their ability to bind formyl peptide determined, taking into account efficiency of transfection and expression of chimeric protein. Based on these results, a ligand binding model is presented in which the second, third, and fourth extracellular (and/or their transmembrane) domains together with the first transmembrane domain form a ligand binding pocket for formyl peptides. It is proposed that the amino-terminal domain plays a role by presumably providing a "lid" to the pocket. The carboxyl-terminal cytoplasmic tail appears to modulate ligand binding by regulating receptor affinity.

  17. Gastrin releasing peptide (GRP) receptor targeted radiopharmaceuticals: A concise update

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.J.; Volkert, W.A.; Hoffman, T.J. E-mail: HoffmanT@health.missouri.edu

    2003-11-01

    The gastrin releasing peptide (GRP) receptor is becoming an increasingly attractive target for development of new radiolabeled peptides with diagnostic and therapeutic potential. The attractiveness of the GRP receptor as a target is based upon the functional expression of GRP receptors in several tumors of neuroendocrine origin including prostate, breast, and small cell lung cancer. This concise review outlines some of the efforts currently underway to develop new GRP receptor specific radiopharmaceuticals by employing a variety of radiometal chelation systems.

  18. Update: improvement strategies for peptide receptor scintigraphy and radionuclide therapy.

    Science.gov (United States)

    de Visser, Monique; Verwijnen, Suzanne M; de Jong, Marion

    2008-04-01

    Somatostatin receptor-targeting peptides are widely used for the imaging and therapy of neuroendocrine tumors. Peptide-receptor radionuclide therapy (PRRT) in neuroendocrine tumor patients with radiolabeled somatostatin analogs has resulted in symptomatic improvement, prolonged survival, and enhanced quality of life. The side-effects of PRRT are few and mostly mild, certainly when using kidney protective agents. If a more widespread use of PRRT is possible, such therapy might become the therapy of first choice in patients with metastasized or inoperable neuroendocrine gastroenteropancreatic tumors. Yet, much profit can be gained from improving the receptor-targeting strategies available and developing new strategies. This review presents an overview of several options to optimize receptor-targeted imaging and radionuclide therapy. These include the optimization of peptide analogs, increasing the number of receptors on the tumor site, and combining PRRT with other treatment strategies. The development of new peptide analogs with increased receptor-binding affinity and improved stability might lead to a higher accumulation of radioactivity inside tumor cells. Analogs of somatostatin have been widely studied. However, much profit can be gained in improving peptide analogs targeting other tumor-related receptors, including gastrin-releasing peptide (GRP) receptors, neurotensin (NT) receptors, cholecystokinin (CCK) receptors, and glucagon-like peptide-1 (GLP-1) receptors. Several peptide analogs targeting these receptors are well on their way to clinical utilization. The literature shows that it is possible to increase the receptor density on tumor cells by using different methods, which results in higher binding and internalization rates and thus a higher contrast during peptide-receptor scintigraphy. In PRRT treatment, this would enable the administration of higher therapeutic doses to tumors, which might lead to a higher cure rate in patients. Combinations of

  19. Parathyroid hormone-related protein blood test

    Science.gov (United States)

    ... ency/article/003691.htm Parathyroid hormone-related protein blood test To use the sharing features on this page, ... measures the level of a hormone in the blood, called parathyroid hormone-related protein. How the Test is Performed A blood sample is needed . How ...

  20. 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

  1. Novel mutations in the transmembrane natriuretic peptide receptor ...

    Indian Academy of Sciences (India)

    All children with AMDM and their available parents were examined and anthropometric measurements ... natriuretic peptide receptor; NPR2 gene. Journal of Genetics, DOI 10.1007/s12041-016-0715-1, Vol. 95, No. .... Here, we describe four children with mutation proved acromesomelic dysplasia, Marteaux type. All four ...

  2. Melanocortin Receptors, Melanotropic Peptides and Penile Erection

    OpenAIRE

    King, Stephen H.; Mayorov, Alexander V.; Balse-Srinivasan, Preeti; Hruby, Victor J.; Vanderah, Todd W.; Wessells, Hunter

    2007-01-01

    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.

  3. Designer interface peptide grafts target estrogen receptor alpha dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S. [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Asare, B.K. [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States); Biswas, P.K., E-mail: pbiswas@tougaloo.edu [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Rajnarayanan, R.V., E-mail: rajendra@buffalo.edu [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States)

    2016-09-09

    The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

  4. Peptide Receptor Radionuclide Therapy-Induced Gitelman-like Syndrome.

    Science.gov (United States)

    Negro, Aurelio; Rossi, Giovanni M; Nicoli, Davide; Versari, Annibale; Farnetti, Enrico; Santi, Rosaria; De Pietri, Stefano

    2017-11-01

    Peptide receptor radionuclide therapy (PRRT) is a molecular-targeted therapy in which a somatostatin analogue (a small peptide) is coupled with a radioligand so that the radiation dose is selectively administered to somatostatin receptor-expressing metastasized neuroendocrine tumors, particularly gastroenteropancreatic. Reported toxicities include myelotoxicity and nephrotoxicity, the latter manifesting as decreased kidney function, often developing months to years after treatment completion. We present a case of PRRT-induced kidney toxicity manifesting as a severe Gitelman-like tubulopathy with preserved kidney function. Because profound hypokalemia and hypocalcemia can lead to life-threatening arrhythmias, we highlight the necessity for careful monitoring of serum and urine electrolytes in patients receiving PRRT. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  5. Radiometallated receptor-avid peptide conjugates for specific in vivo targeting of cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, T.J.; Quinn, T.P.; Volkert, W.A. E-mail: VolkertW@health.missouri.edu

    2001-07-01

    New receptor-avid radiotracers are being developed for site-specific in vivo targeting of a myriad of receptors expressed on cancer cells. This review exemplifies strategies being used to design radiometallated peptide conjugates that maximize uptake in tumors and optimize their in vivo pharmacokinetic properties. Efforts to produce synthetic peptide analogues that target the following three receptor systems are highlighted: Gastrin releasing peptide (GRP), alpha-melanocyte stimulating hormone ({alpha}-MSH), and guanylate cyclase-C (GC-C) receptors.

  6. Small-molecule agonists for the glucagon-like peptide 1 receptor

    DEFF Research Database (Denmark)

    Knudsen, Lotte Bjerre; Kiel, Dan; Teng, Min

    2007-01-01

    The peptide hormone glucagon-like peptide (GLP)-1 has important actions resulting in glucose lowering along with weight loss in patients with type 2 diabetes. As a peptide hormone, GLP-1 has to be administered by injection. Only a few small-molecule agonists to peptide hormone receptors have been...... described and none in the B family of the G protein coupled receptors to which the GLP-1 receptor belongs. We have discovered a series of small molecules known as ago-allosteric modulators selective for the human GLP-1 receptor. These compounds act as both allosteric activators of the receptor...

  7. Development of second generation peptides modulating cellular adiponectin receptor responses

    Science.gov (United States)

    Otvos, Laszlo; Knappe, Daniel; Hoffmann, Ralf; Kovalszky, Ilona; Olah, Julia; Hewitson, Tim; Stawikowska, Roma; Stawikowski, Maciej; Cudic, Predrag; Lin, Feng; Wade, John; Surmacz, Eva; Lovas, Sandor

    2014-10-01

    The adipose tissue participates in the regulation of energy homeostasis as an important endocrine organ that secretes a number of biologically active adipokines, including adiponectin. Recently we developed and characterized a first-in-class peptide-based adiponectin receptor agonist by using in vitro and in vivo models of glioblastoma and breast cancer (BC). In the current study, we further explored the effects of peptide ADP355 in additional cellular models and found that ADP355 inhibited chronic myeloid leukemia (CML) cell proliferation and renal myofibroblast differentiation with mid-nanomolar IC50 values. According to molecular modeling calculations, ADP355 was remarkably flexible in the global minimum with a turn present in the middle of the peptide. Considering these structural features of ADP355 and the fact that adiponectin normally circulates as multimeric complexes, we developed and tested the activity of a linear branched dimer (ADP399). The dimer exhibited approximately 20-fold improved cellular activity inhibiting K562 CML and MCF-7 cell growth with high pM - low nM relative IC50 values. Biodistribution studies suggested superior tissue dissemination of both peptides after subcutaneous administration relative to intraperitoneal inoculation. After screening of a 397-member adiponectin active site library, a novel octapeptide (ADP400) was designed that counteracted 10-1000 nM ADP355- and ADP399-mediated effects on CML and BC cell growth at nanomolar concentrations. ADP400 induced mitogenic effects in MCF-7 BC cells perhaps due to antagonizing endogenous adiponectin actions or acting as an inverse agonist. While the linear dimer agonist ADP399 meets pharmacological criteria of a contemporary peptide drug lead, the peptide showing antagonist activity (ADP400) at similar concentrations will be an important target validation tool to study adiponectin functions.

  8. Development of second generation peptides modulating cellular adiponectin receptor responses

    Directory of Open Access Journals (Sweden)

    Laszlo eOtvos

    2014-10-01

    Full Text Available The adipose tissue participates in the regulation of energy homeostasis as an important endocrine organ that secretes a number of biologically active adipokines, including adiponectin. Recently we developed and characterized a first-in-class peptide-based adiponectin receptor agonist by using in vitro and in vivo models of glioblastoma and breast cancer (BC. In the current study, we further explored the effects of peptide ADP355 in additional cellular models and found that ADP355 inhibited chronic myeloid leukemia (CML cell proliferation and renal myofibroblast differentiation with mid-nanomolar IC50 values. According to molecular modeling calculations, ADP355 was remarkably flexible in the global minimum with a turn present in the middle of the peptide. Considering these structural features of ADP355 and the fact that adiponectin normally circulates as multimeric complexes, we developed and tested the activity of a linear branched dimer (ADP399. The dimer exhibited approximately 20-fold improved cellular activity inhibiting K562 CML and MCF-7 cell growth with high pM - low nM relative IC50 values. Biodistribution studies suggested superior tissue dissemination of both peptides after subcutaneous administration relative to intraperitoneal inoculation. After screening of a 397-member adiponectin active site library, a novel octapeptide (ADP400 was designed that counteracted 10-1000 nM ADP355- and ADP399-mediated effects on CML and BC cell growth at nanomolar concentrations. ADP400 induced mitogenic effects in MCF-7 BC cells perhaps due to antagonizing endogenous adiponectin actions or acting as an inverse agonist. While the linear dimer agonist ADP399 meets pharmacological criteria of a contemporary peptide drug lead, the peptide showing antagonist activity (ADP400 at similar concentrations will be an important target validation tool to study adiponectin functions.

  9. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, V 220, Rotterdam (Netherlands); Boerman, Otto C. [Radboud University Hospital, Department of Nuclear Medicine, Nijmegen (Netherlands)

    2010-05-15

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  10. Genetic Algorithm Managed Peptide Mutant Screening: Optimizing Peptide Ligands for Targeted Receptor Binding.

    Science.gov (United States)

    King, Matthew D; Long, Thomas; Andersen, Timothy; McDougal, Owen M

    2016-12-27

    This study demonstrates the utility of genetic algorithms to search exceptionally large and otherwise intractable mutant libraries for sequences with optimal binding affinities for target receptors. The Genetic Algorithm Managed Peptide Mutant Screening (GAMPMS) program was used to search an α-conotoxin (α-CTx) MII mutant library of approximately 41 billion possible peptide sequences for those exhibiting the greatest binding affinity for the α3β2-nicotinic acetylcholine receptor (nAChR) isoform. A series of top resulting peptide ligands with high sequence homology was obtained, with each mutant having an estimated ΔGbind approximately double that of the potent native α-CTx MII ligand. A consensus sequence from the top GAMPMS results was subjected to more rigorous binding free energy calculations by molecular dynamics and compared to α-CTx MII and other related variants for binding with α3β2-nAChR. In this study, the efficiency of GAMPMS to substantially reduce the sample population size through evolutionary selection criteria to produce ligands with higher predicted binding affinity is demonstrated.

  11. G-Protein Coupled Receptors Targeted by Analgesic Venom Peptides

    Directory of Open Access Journals (Sweden)

    James T. Daniel

    2017-11-01

    Full Text Available Chronic pain is a complex and debilitating condition associated with a large personal and socioeconomic burden. Current pharmacological approaches to treating chronic pain such as opioids, antidepressants and anticonvulsants exhibit limited efficacy in many patients and are associated with dose-limiting side effects that hinder their clinical use. Therefore, improved strategies for the pharmacological treatment of pathological pain are urgently needed. G-protein coupled receptors (GPCRs are ubiquitously expressed on the surface of cells and act to transduce extracellular signals and regulate physiological processes. In the context of pain, numerous and diverse families of GPCRs expressed in pain pathways regulate most aspects of physiological and pathological pain and are thus implicated as potential targets for therapy of chronic pain. In the search for novel compounds that produce analgesia via GPCR modulation, animal venoms offer an enormous and virtually untapped source of potent and selective peptide molecules. While many venom peptides target voltage-gated and ligand-gated ion channels to inhibit neuronal excitability and blunt synaptic transmission of pain signals, only a small proportion are known to interact with GPCRs. Of these, only a few have shown analgesic potential in vivo. Here we review the current state of knowledge regarding venom peptides that target GPCRs to produce analgesia, and their development as therapeutic compounds.

  12. Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors.

    Science.gov (United States)

    Roosenburg, Susan; Laverman, Peter; van Delft, Floris L; Boerman, Otto C

    2011-11-01

    Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emission computed tomography imaging. A variety of radiolabeled CCK/gastrin-related peptides has been synthesized and characterized for imaging. All peptides have the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-Phe-NH(2) in common or derivatives thereof. This review focuses on the development and application of radiolabeled CCK/gastrin peptides for radionuclide imaging and radionuclide therapy of tumors expressing CCK receptors. We discuss both preclinical studies as well as clinical studies with CCK and gastrin peptides.

  13. [Ala12]MCD peptide: a lead peptide to inhibitors of immunoglobulin E binding to mast cell receptors.

    Science.gov (United States)

    Buku, A; Condie, B A; Price, J A; Mezei, M

    2005-09-01

    An effort was made to discover mast cell degranulating (MCD) peptide analogs that bind with high affinity to mast cell receptors without triggering secretion of histamine or other mediators of the allergic reaction initiated by immunoglobulin E (IgE) after mast cell activation. Such compounds could serve as inhibitors of IgE binding to mast cell receptors. An alanine scan of MCD peptide reported previously showed that the analog [Ala12]MCD was 120-fold less potent in histamine-releasing activity and fivefold more potent in binding affinity to mast cell receptors than the parent MCD peptide. Because this analog showed marginal intrinsic activity and good binding affinity it was subsequently tested in the present study as an IgE inhibitor. In contrast to MCD peptide, [Ala12]MCD showed a 50% inhibition of IgE binding to the Fc epsilon RI alpha mast cell receptor by using rat basophilic leukemia (RBL-2H3) mast cells and fluorescence polarization. Furthermore, in a beta-hexosaminidase secretory assay, the peptide also showed a 50% inhibition of the secretion of this enzyme caused by IgE. An attempt was made to relate structural changes and biologic differences between the [Ala12]MCD analog and the parent MCD peptide. The present results show that [Ala12]MCD may provide a base for designing agents to prevent IgE/Fc epsilon RI alpha interactions and, consequently, allergic conditions.

  14. Porcine brain natriuretic peptide receptor in bovine adrenal cortex

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, K.; Hashiguchi, T.; Ohashi, M.; Takayanagi, R.; Haji, M.; Matsuo, H.; Nawata, H.

    1989-01-01

    The action of porcine brain natriuretic peptide (pBNP) on the steroidogenesis was investigated in cultured bovine adrenocortical cells. Porcine BNP induced a significant dose-dependent inhibition of both ACTH- and A II-stimulated aldosterone secretion. 10/sup /minus/8/M and 10/sup /minus/7/M pBNP also significantly inhibited ACTH-stimulated cortisol and dehydroepiandrosterone (DHEA) secretions. Binding studies of (/sup 125/I)-pBNP to bovine adrenocortical membrane fractions showed that adrenal cortex had high-affinity and low-capacity pBNP binding sites, with a dissociation constant (Kd) of 1.70 x 10/sup /minus/10/M and a maximal binding capacity (Bmax) of 19.9 fmol/mg protein. Finally, the 135 Kd radioactive band was specially visualized in the affinity labeling of bovine adrenal cortex with disuccinimidyl suberate (DSS). These results suggest that pBNP may have receptor-mediated suppressive actions on bovine adrenal steroidogenesis, similar to that in atrial natriuretic peptide (ANP).

  15. Common peptides shed light on evolution of Olfactory Receptors

    Directory of Open Access Journals (Sweden)

    Lancet Doron

    2009-05-01

    Full Text Available Abstract Background Olfactory Receptors (ORs form the largest multigene family in vertebrates. Their evolution and their expansion in the vertebrate genomes was the subject of many studies. In this paper we apply a motif-based approach to this problem in order to uncover evolutionary characteristics. Results We extract deterministic motifs from ORs belonging to ten species using the MEX (Motif Extraction algorithm, thus defining Common Peptides (CPs characteristic to ORs. We identify species-specific CPs and show that their relative abundance is high only in fish and frog, suggesting relevance to water-soluble odorants. We estimate the origins of CPs according to the tree of life and track the gains and losses of CPs through evolution. We identify major CP gain in tetrapods and major losses in reptiles. Although the number of human ORs is less than half of the number of ORs in other mammals, the fraction of lost CPs is only 11%. By examining the positions of CPs along the OR sequence, we find two regions that expanded only in tetrapods. Using CPs we are able to establish remote homology relations between ORs and non-OR GPCRs. Selecting CPs according to their evolutionary age, we bicluster ORs and CPs for each species. Clean biclustering emerges when using relatively novel CPs. Evolutionary age is used to track the history of CP acquisition in the collection of mammalian OR families within HORDE (Human Olfactory Receptor Data Explorer. Conclusion The CP method provides a novel perspective that reveals interesting traits in the evolution of olfactory receptors. It is consistent with previous knowledge, and provides finer details. Using available phylogenetic trees, evolution can be rephrased in terms of CP origins. Supplementary information is also available at http://adios.tau.ac.il/ORPS

  16. Combining elements from two antagonists of formyl peptide receptor 2 generates more potent peptidomimetic antagonists

    DEFF Research Database (Denmark)

    Skovbakke, Sarah Line; Holdfeldt, Andre; Nielsen, Christina

    2017-01-01

    Structural optimization of a peptidomimetic antagonist of formyl peptide receptor 2 (FPR2) was explored by an approach involving combination of elements from the two most potent FPR2 antagonists described: a Rhodamine B-conjugated 10-residue gelsonin-derived peptide (i.e., PBP10, RhB-QRLFQVKGRR-O......Structural optimization of a peptidomimetic antagonist of formyl peptide receptor 2 (FPR2) was explored by an approach involving combination of elements from the two most potent FPR2 antagonists described: a Rhodamine B-conjugated 10-residue gelsonin-derived peptide (i.e., PBP10, Rh...

  17. Practıcal Aspects of 68Ga-Labelled Dota-Peptides for Peptide-Receptor Radionuclide Therapy

    OpenAIRE

    Taşdelen, Betül

    2016-01-01

    68Gallium-labeled receptor ligands, such as 68Gallium DOTATOC, 68Gallium-DOTANOC, and68Gallium-DOTATATE which are used in PET are becoming gold standard of 68Ga-labeled peptides.The 68Ga-labeled peptides show a rapid renal clearance and are rapidly accumulated in the tumors (80%within 30 minutes); concentration in tissues without expression of somatostatin receptors is low,providing higher contrast imaging. Here, this paper presents the practical aspects and the results ofpreparation and radi...

  18. A novel antimicrobial peptide isolated from centipede Scolopendra subspinipes mutilans stimulates neutrophil activity through formyl peptide receptor 2.

    Science.gov (United States)

    Park, Yoo Jung; Kim, Hyung Sik; Lee, Ha Young; Hwang, Jae Sam; Bae, Yoe-Sik

    2017-12-09

    In this study, we identified scolopendrasin X, a novel antimicrobial peptide (AMP), from centipede Scolopendra subspinipes mutilans. Scolopendrasin X strongly stimulated mouse neutrophils, resulting in intracellular calcium increase, chemotactic migration through pertussis toxin-sensitive G-protein and phospholipase C pathway, and increased superoxide anion production in neutrophils. Target receptor for scolopendrasin X, formyl peptide receptor (FPR)2 mediated scolopendrasin X-induced neutrophil activation. Moreover, scolopendrasin X significantly blocked inflammatory cytokine production induced by lipopolysaccharide in mouse neutrophils. Taken together, our results suggest that the novel AMP scolopendrasin X can be used as a material to regulate neutrophil activity through FPR2. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors

    NARCIS (Netherlands)

    Roosenburg, S.; Laverman, P.; Delft, F.L. van; Boerman, O.C.

    2011-01-01

    Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a

  20. Synthesis and evaluation of intercalating somatostatin receptor binding peptide conjugates for endoradiotherapy

    National Research Council Canada - National Science Library

    Graham, Keith; Wang, Qin; Garcia Boy, Regine; Eisenhut, Michael; Haberkorn, Uwe; Mier, Walter

    2007-01-01

    .... In order to exploit the cytotoxic potential of intercalator-Auger-emitter conjugates, bis-benzimidazole dyes, Hoechst 33258 and 33342, were linked to a somatostatin receptor affine carrier peptide...

  1. Characterization of glucagon-like peptide-1 receptor beta-arrestin 2 interaction: a high-affinity receptor phenotype

    DEFF Research Database (Denmark)

    Jorgensen, Rasmus; Martini, Lene; Schwartz, Thue W

    2005-01-01

    that (beta)arr2 interaction locks the receptor in a high-affinity conformation, which can be explored by some, but not all, ligands. The fusion constructs adopted a signaling phenotype governed by the tethered (beta)arr2 with an attenuated G protein-mediated cAMP signal and a higher maximal internalization...... for the fusion constructs was observed. We conclude that the glucagon-like peptide 1 fusion construct mimics the natural interaction of the receptor with (beta)arr2 with respect to binding peptide ligands, G protein-mediated signaling and internalization, and that this distinct molecular phenotype is reminiscent......To dissect the interaction between beta-arrestin ((beta)arr) and family B G protein-coupled receptors, we constructed fusion proteins between the glucagon-like peptide 1 receptor and (beta)arr2. The fusion constructs had an increase in apparent affinity selectively for glucagon, suggesting...

  2. Antimicrobial peptide scolopendrasin VII, derived from the centipede Scolopendra subspinipes mutilans, stimulates macrophage chemotaxis via formyl peptide receptor 1.

    Science.gov (United States)

    Park, Yoo Jung; Lee, Ha Young; Jung, Young Su; Park, Joon Seong; Hwang, Jae Sam; Bae, Yoe-Sik

    2015-08-01

    In this study, we report that one of the antimicrobial peptides scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates actin polymerization and the subsequent chemotactic migration of macrophages through the activation of ERK and protein kinase B (Akt) activity. The scolopendrasin VII-induced chemotactic migration of macrophages is inhibited by the formyl peptide receptor 1 (FPR1) antagonist cyclosporine H. We also found that scolopendrasin VII stimulate the chemotactic migration of FPR1-transfected RBL-2H3 cells, but not that of vector-transfected cells; moreover, scolopendrasin VII directly binds to FPR1. Our findings therefore suggest that the antimicrobial peptide scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates macrophages, resulting in chemotactic migration via FPR1 signaling, and the peptide can be useful in the study of FPR1-related biological responses.

  3. Structural Basis for Receptor Activity-Modifying Protein-Dependent Selective Peptide Recognition by a G Protein-Coupled Receptor.

    Science.gov (United States)

    Booe, Jason M; Walker, Christopher S; Barwell, James; Kuteyi, Gabriel; Simms, John; Jamaluddin, Muhammad A; Warner, Margaret L; Bill, Roslyn M; Harris, Paul W; Brimble, Margaret A; Poyner, David R; Hay, Debbie L; Pioszak, Augen A

    2015-06-18

    Association of receptor activity-modifying proteins (RAMP1-3) with the G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) enables selective recognition of the peptides calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) that have diverse functions in the cardiovascular and lymphatic systems. How peptides selectively bind GPCR:RAMP complexes is unknown. We report crystal structures of CGRP analog-bound CLR:RAMP1 and AM-bound CLR:RAMP2 extracellular domain heterodimers at 2.5 and 1.8 Å resolutions, respectively. The peptides similarly occupy a shared binding site on CLR with conformations characterized by a β-turn structure near their C termini rather than the α-helical structure common to peptides that bind related GPCRs. The RAMPs augment the binding site with distinct contacts to the variable C-terminal peptide residues and elicit subtly different CLR conformations. The structures and accompanying pharmacology data reveal how a class of accessory membrane proteins modulate ligand binding of a GPCR and may inform drug development targeting CLR:RAMP complexes. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Designer lipid-like peptides: a class of detergents for studying functional olfactory receptors using commercial cell-free systems.

    Directory of Open Access Journals (Sweden)

    Karolina Corin

    Full Text Available A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins.

  5. Ghrelin axis genes, peptides and receptors: recent findings and future challenges.

    Science.gov (United States)

    Seim, Inge; Josh, Peter; Cunningham, Peter; Herington, Adrian; Chopin, Lisa

    2011-06-20

    The ghrelin axis consists of the gene products of the ghrelin gene (GHRL), and their receptors, including the classical ghrelin receptor GHSR. While it is well-known that the ghrelin gene encodes the 28 amino acid ghrelin peptide hormone, it is now also clear that the locus encodes a range of other bioactive molecules, including novel peptides and non-coding RNAs. For many of these molecules, the physiological functions and cognate receptor(s) remain to be determined. Emerging research techniques, including proteogenomics, are likely to reveal further ghrelin axis-derived molecules. Studies of the role of ghrelin axis genes, peptides and receptors, therefore, promises to be a fruitful area of basic and clinical research in years to come. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  6. Novel thrombopoietin mimetic peptides bind c-Mpl receptor: Synthesis, biological evaluation and molecular modeling.

    Science.gov (United States)

    Liu, Yaquan; Tian, Fang; Zhi, Dejuan; Wang, Haiqing; Zhao, Chunyan; Li, Hongyu

    2017-02-01

    Thrombopoietin (TPO) acts in promoting the proliferation of hematopoietic stem cells and by initiating specific maturation events in megakaryocytes. Now, TPO-mimetic peptides with amino acid sequences unrelated to TPO are of considerable pharmaceutical interest. In the present paper, four new TPO mimetic peptides that bind and activate c-Mpl receptor have been identified, synthesized and tested by Dual-Luciferase reporter gene assay for biological activities. The molecular modeling research was also approached to understand key molecular mechanisms and structural features responsible for peptide binding with c-Mpl receptor. The results presented that three of four mimetic peptides showed significant activities. In addition, the molecular modeling approaches proved hydrophobic interactions were the driven positive forces for binding behavior between peptides and c-Mpl receptor. TPO peptide residues in P7, P13 and P7' positions were identified by the analysis of hydrogen bonds and energy decompositions as the key ones for benefiting better biological activities. Our data suggested the synthesized peptides have considerable potential for the future development of stable and highly active TPO mimetic peptides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Assembly of high-affinity insulin receptor agonists and antagonists from peptide building blocks

    Science.gov (United States)

    Schäffer, Lauge; Brissette, Renee E.; Spetzler, Jane C.; Pillutla, Renuka C.; Østergaard, Søren; Lennick, Michael; Brandt, Jakob; Fletcher, Paul W.; Danielsen, Gillian M.; Hsiao, Ku-Chuan; Andersen, Asser S.; Dedova, Olga; Ribel, Ulla; Hoeg-Jensen, Thomas; Hertz Hansen, Per; Blume, Arthur J.; Markussen, Jan; Goldstein, Neil I.

    2003-04-01

    Insulin is thought to elicit its effects by crosslinking the two extracellular -subunits of its receptor, thereby inducing a conformational change in the receptor, which activates the intracellular tyrosine kinase signaling cascade. Previously we identified a series of peptides binding to two discrete hotspots on the insulin receptor. Here we show that covalent linkage of such peptides into homodimers or heterodimers results in insulin agonists or antagonists, depending on how the peptides are linked. An optimized agonist has been shown, both in vitro and in vivo, to have a potency close to that of insulin itself. The ability to construct such peptide derivatives may offer a path for developing agonists or antagonists for treatment of a wide variety of diseases.

  8. Crystal structure of the human urokinase plasminogen activator receptor bound to an antagonist peptide

    DEFF Research Database (Denmark)

    Llinas, Paola; Le Du, Marie Hélène; Gårdsvoll, Henrik

    2005-01-01

    . This knowledge combined with the discovery of a convergent binding motif shared by the antagonist peptide and uPA allowed us to build a model of the human uPA-uPAR complex. This model reveals that the receptor-binding module of uPA engages the uPAR central cavity, thus leaving the external receptor surface...

  9. Different domains of the glucagon and glucagon-like peptide-1 receptors provide the critical determinants of ligand selectivity

    DEFF Research Database (Denmark)

    Runge, S; Wulff, B S; Madsen, K

    2003-01-01

    (1) Glucagon and glucagon-like peptide-1 (GLP-1) are homologous peptide hormones with important functions in glucose metabolism. The receptors for glucagon and GLP-1 are homologous family B G-protein coupled receptors. The GLP-1 receptor amino-terminal extracellular domain is a major determinant...

  10. G protein-coupled receptor quantification using peptide group-specific enrichment combined with internal peptide standard reporter calibration.

    Science.gov (United States)

    Eisen, David; Planatscher, Hannes; Hardie, Darryl B; Kraushaar, Udo; Pynn, Christopher J; Stoll, Dieter; Borchers, Christoph; Joos, Thomas O; Poetz, Oliver

    2013-09-02

    The G protein-coupled receptor (GPCR) super-family comprises the largest and most diverse group of membrane receptors in eukaryotes. GPCRs are involved in a plethora of physiological functions in all kinds of tissues. Detailed knowledge about GPCR presence and expression levels in tissues can be very helpful for drug development as the majority of drugs are designed to modulate membrane receptors. Furthermore, it is known that many adverse drug effects result from GPCR interactions. However, very few satisfactory methods are currently available for the detection and quantification of GPCRs. The detection is complicated by their three-dimensional structure, their hydrophobic properties, and their localization in the plasma membrane with 7-trans-membrane domains and small cytosolic and extracellular domains. Due to these properties it is very difficult to generate specific antibodies directed against GPCRs for sandwich immunoassays and Western blot. We therefore designed an immunoaffinity- and mass spectrometry-based approach to analyze GPCR-specific signature peptides in tryptic digests in rat tissue lysates. The expression levels of four different GPCRs were determined using chemically labeled synthetic standard peptides. Here, we demonstrate for the first time, that peptide immunoaffinity MS-based methods can render a reliable and quantitative analysis of multi-membrane spanning receptor molecules. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Small Molecule Drug Discovery at the Glucagon-Like Peptide-1 Receptor

    Directory of Open Access Journals (Sweden)

    Francis S. Willard

    2012-01-01

    Full Text Available The therapeutic success of peptide glucagon-like peptide-1 (GLP-1 receptor agonists for the treatment of type 2 diabetes mellitus has inspired discovery efforts aimed at developing orally available small molecule GLP-1 receptor agonists. Although the GLP-1 receptor is a member of the structurally complex class B1 family of GPCRs, in recent years, a diverse array of orthosteric and allosteric nonpeptide ligands has been reported. These compounds include antagonists, agonists, and positive allosteric modulators with intrinsic efficacy. In this paper, a comprehensive review of currently disclosed small molecule GLP-1 receptor ligands is presented. In addition, examples of “ligand bias” and “probe dependency” for the GLP-1 receptor are discussed; these emerging concepts may influence further optimization of known molecules or persuade designs of expanded screening strategies to identify novel chemical starting points for GLP-1 receptor drug discovery.

  12. Oxytocin releases atrial natriuretic peptide by combining with oxytocin receptors in the heart

    OpenAIRE

    Gutkowska, Jolanta; Jankowski, Marek; Lambert, Chantal; Mukaddam-Daher, Suhayla; Zingg, Hans H.; McCann, Samuel M.

    1997-01-01

    Previous studies indicated that the central nervous system induces release of the cardiac hormone atrial natriuretic peptide (ANP) by release of oxytocin from the neurohypophysis. The presence of specific transcripts for the oxytocin receptor was demonstrated in all chambers of the heart by amplification of cDNA by the PCR using specific oligonucleotide primers. Oxytocin receptor mRNA content in the heart is 10 times lower than in the uterus of female rats. Oxytocin receptor transcripts were ...

  13. Peptides in receptor-mediated radiotherapy : from design to the clinical application in cancers.

    Directory of Open Access Journals (Sweden)

    Catherine eLOZZA

    2013-09-01

    Full Text Available Short peptides can show high affinity for specific receptors overexpressed on tumor cells. Some of these are already used in cancerology as diagnostic tools and others are in clinical trials for therapeutic applications. Therefore, peptides exhibit great potential as a diagnostic tool but also as an alternative or an additional antitumoral approach upon the covalent attachment of a therapeutic moiety such as a radionuclide or a cytotoxic drug. The chemistry offers flexibility to graft onto the targeting peptide either fluorine or iodine directly, or metallic radionuclides through appropriate chelating agent. Since short peptides are straightforward to synthesize, there is an opportunity to further improve existing peptides or to design new ones for clinical applications. However, several considerations have to be taken into account to optimize the recognition properties of the targeting peptide to its receptor, to improve its stability in the biological fluids and its residence in the body, or to increase its overall therapeutic effect. In this review, we highlight the different aspects which need to be considered for the development of an efficient peptide receptor-mediated radionuclide therapy in different neoplasms.

  14. Harnessing glucagon-like peptide-1 receptor agonists for the pharmacological treatment of overweight and obesity.

    Science.gov (United States)

    Burcelin, R; Gourdy, P

    2017-01-01

    Over the past 30 years, there has been a dramatic rise in global obesity prevalence, resulting in significant economic and social consequences. Attempts to develop pharmacological agents to treat obesity have met with many obstacles including the lack of long-term effectiveness and the potential for adverse effects. Historically, there have been limited treatment options for overweight and obesity; however, since 2012, a number of new drugs have become available. A number of peptides produced in the gut act as key mediators of the gut-brain axis, which is involved in appetite regulation. This review discusses the role of the gut-brain axis in appetite regulation with special focus on glucagon-like peptide-1. Liraglutide 3.0 mg, a glucagon-like peptide-1 receptor agonist that targets this pathway, is now approved for the treatment of obesity and overweight (body mass index ≥27 kg/m2 ) with comorbidities such as type 2 diabetes, high blood pressure, high cholesterol or obstructive sleep apnoea. In addition, other glucagon-like peptide-1 receptor agonists offer promise for obesity management in the future. This review examines how glucagon-like peptide-1 receptor agonists promote weight loss and summarizes the clinical data on weight loss with glucagon-like peptide-1 receptor agonists. © 2016 The Authors Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.

  15. Concomitant duplications of opioid peptide and receptor genes before the origin of jawed vertebrates.

    Directory of Open Access Journals (Sweden)

    Görel Sundström

    Full Text Available BACKGROUND: The opioid system is involved in reward and pain mechanisms and consists in mammals of four receptors and several peptides. The peptides are derived from four prepropeptide genes, PENK, PDYN, PNOC and POMC, encoding enkephalins, dynorphins, orphanin/nociceptin and beta-endorphin, respectively. Previously we have described how two rounds of genome doubling (2R before the origin of jawed vertebrates formed the receptor family. METHODOLOGY/PRINCIPAL FINDINGS: Opioid peptide gene family members were investigated using a combination of sequence-based phylogeny and chromosomal locations of the peptide genes in various vertebrates. Several adjacent gene families were investigated similarly. The results show that the ancestral peptide gene gave rise to two additional copies in the genome doublings. The fourth member was generated by a local gene duplication, as the genes encoding POMC and PNOC are located on the same chromosome in the chicken genome and all three teleost genomes that we have studied. A translocation has disrupted this synteny in mammals. The PDYN gene seems to have been lost in chicken, but not in zebra finch. Duplicates of some peptide genes have arisen in the teleost fishes. Within the prepropeptide precursors, peptides have been lost or gained in different lineages. CONCLUSIONS/SIGNIFICANCE: The ancestral peptide and receptor genes were located on the same chromosome and were thus duplicated concomitantly. However, subsequently genetic linkage has been lost. In conclusion, the system of opioid peptides and receptors was largely formed by the genome doublings that took place early in vertebrate evolution.

  16. New Insights into Ligand-Receptor Pairing and Coevolution of Relaxin Family Peptides and Their Receptors in Teleosts

    Directory of Open Access Journals (Sweden)

    Sara Good

    2012-01-01

    Full Text Available Relaxin-like peptides (RLN/INSL play diverse roles in reproductive and neuroendocrine processes in placental mammals and are functionally associated with two distinct types of receptors (RXFP for each respective function. The diversification of RLN/INSL and RXFP gene families in vertebrates was predominantly driven by whole genome duplications (2R and 3R. Teleosts preferentially retained duplicates of genes putatively involved in neuroendocrine regulation, harboring a total of 10-11 receptors and 6 ligand genes, while most mammals have equal numbers of ligands and receptors. To date, the ligand-receptor relationships of teleost Rln/Insl peptides and their receptors have largely remained unexplored. Here, we use selection analyses based on sequence data from 5 teleosts and qPCR expression data from zebrafish to explore possible ligand-receptor pairings in teleosts. We find support for the hypothesis that, with the exception of RLN, which has undergone strong positive selection in mammalian lineages, the ligand and receptor genes shared between mammals and teleosts appear to have similar pairings. On the other hand, the teleost-specific receptors show evidence of subfunctionalization. Overall, this study underscores the complexity of RLN/INSL and RXFP ligand-receptor interactions in teleosts and establishes theoretical background for further experimental work in nonmammals.

  17. Peptide Receptor Radionuclide Therapy with radiolabelled somatostatin analogues in patients with somatostatin receptor positive tumours

    Energy Technology Data Exchange (ETDEWEB)

    Essen, Martijn van; Krenning, Eric P.; Jong, Marion De; Valkema, Roelf; Kwekkeboom, Dik J. [Dept. of Nuclear Medicine, Erasmus MC, ' s Gravendijkwal 230, Rotterdam (Netherlands)

    2007-08-15

    Peptide Receptor Radionuclide Therapy (PRRT) with radiolabelled somatostatin analogues is a promising treatment option for patients with inoperable or metastasised neuroendocrine tumours. Symptomatic improvement may occur with all of the various {sup 111}In, {sup 90}Y, or {sup 177}Lu-labelled somatostatin analogues that have been used. Since tumour size reduction was seldom achieved with {sup 111}Indium labelled somatostatin analogues, radiolabelled somatostatin analogues with beta-emitting isotopes like {sup 90}Y and {sup 177}Lu were developed. Reported anti-tumour effects of [{sup 90}Y-DOTA0,Tyr3]octreotide vary considerably between various studies: Tumour regression of 50% or more was achieved in 9 to 33% (mean 22%). With [{sup 177}Lu-DOTA0,Tyr3]octreotate treatments, tumour regression of 50% or more was achieved in 28% of patients and tumour regression of 25 to 50% in 19% of patients, stable disease was demonstrated in 35% and progressive disease in 18%. Predictive factors for tumour remission were high tumour uptake on somatostatin receptor scintigraphy and limited amount of liver metastases. The side-effects of PRRT are few and mostly mild, certainly when using renal protective agents: Serious side-effects like myelodysplastic syndrome or renal failure are rare. The median duration of the therapy response for [{sup 90}Y-DOTA0,Tyr3]octreotide and [{sup 177}Lu-DOTA0,Tyr3]octreotate is 30 months and more than 36 months respectively. Lastly, quality of life improves significantly after treatment with [{sup 177}Lu-DOTA0,Tyr3]octreotate. These data compare favourably with the limited number of alternative treatment approaches, like chemotherapy. If more widespread use of PRRT is possible, such therapy might become the therapy of first choice in patients with metastasised or inoperable gastroenteropancreatic neuroendocrine tumours. Also the role in somatostatin receptor expressing non-GEP tumours, like metastasised paraganglioma/pheochromocytoma and non

  18. Dynamics of urokinase receptor interaction with Peptide antagonists studied by amide hydrogen exchange and mass spectrometry

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J D; Gårdsvoll, Henrik; Danø, Keld

    2004-01-01

    on the peptide ligand. This yields bimodal isotope patterns from which dissociation rate constants can be determined. In addition, the distinct bimodal isotope distributions also allow investigation of the exchange kinetics of receptor-bound peptides providing information about the local structural motions......Using amide hydrogen exchange combined with electrospray ionization mass spectrometry, we have in this study determined the number of amide hydrogens on several peptides that become solvent-inaccessible as a result of their high-affinity interaction with the urokinase-type plasminogen activator...... hydrogens in the receptor complex. Interestingly, a naturally occurring O-linked fucose on Thr(18) confers protection of two additional amide hydrogens in GFD when it forms a complex with uPAR. Dissociation of the uPAR-peptide complexes is accompanied by a correlated exchange of nearly all amide hydrogens...

  19. Glucagon-like peptide-1 receptors in the brain: controlling food intake and body weight

    OpenAIRE

    Baggio, Laurie L.; Drucker, Daniel. J.

    2014-01-01

    The peptide hormone glucagon-like peptide-1 (GLP-1) enhances glucose-induced insulin secretion and inhibits both gastric emptying and glucagon secretion. GLP-1 receptor (GLP-1R) agonists control glycemia via glucose-dependent mechanisms of action and promote weight loss in obese and diabetic individuals. Nevertheless, the mechanisms and cellular targets transducing the weight loss effects remain unclear. Two recent studies in the JCI provide insight into the neurons responsible for this effec...

  20. Targeting Interleukin-4 Receptor Alpha by Hybrid Peptide for Novel Biliary Tract Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Kahori Seto

    2014-01-01

    Full Text Available It is known that the interleukin-4 receptor α (IL-4Rα is highly expressed on the surface of various human solid tumors. We previously designed novel IL-4Rα-lytic hybrid peptide composed of binding peptide to IL-4Rα and cell-lytic peptide and reported that the designed IL-4Rα-lytic hybrid peptide exhibited cytotoxic and antitumor activity both in vitro and in vivo against the human pancreatic cancer cells expressing IL-4Rα. Here, we evaluated the antitumor activity of the IL-4Rα-lytic hybrid peptide as a novel molecular targeted therapy for human biliary tract cancer (BTC. The IL-4Rα-lytic hybrid peptide showed cytotoxic activity in six BTC cell lines with a concentration that killed 50% of all cells (IC50 as low as 5 μM. We also showed that IL-4Rα-lytic hybrid peptide in combination with gemcitabine exhibited synergistic cytotoxic activity in vitro. In addition, intravenous administration of IL-4Rα-lytic hybrid peptide significantly inhibited tumor growth in a xenograft model of human BTC in vivo. Taken together, these results indicated that the IL-4Rα-lytic hybrid peptide is a potent agent that might provide a novel therapy for patients with BTC.

  1. Distinct Signaling Cascades Elicited by Different Formyl Peptide Receptor 2 (FPR2 Agonists

    Directory of Open Access Journals (Sweden)

    Fabio Cattaneo

    2013-04-01

    Full Text Available The formyl peptide receptor 2 (FPR2 is a remarkably versatile transmembrane protein belonging to the G-protein coupled receptor (GPCR family. FPR2 is activated by an array of ligands, which include structurally unrelated lipids and peptide/proteins agonists, resulting in different intracellular responses in a ligand-specific fashion. In addition to the anti-inflammatory lipid, lipoxin A4, several other endogenous agonists also bind FPR2, including serum amyloid A, glucocorticoid-induced annexin 1, urokinase and its receptor, suggesting that the activation of FPR2 may result in potent pro- or anti-inflammatory responses. Other endogenous ligands, also present in biological samples, include resolvins, amyloidogenic proteins, such as beta amyloid (Aβ-42 and prion protein (Prp106–126, the neuroprotective peptide, humanin, antibacterial peptides, annexin 1-derived peptides, chemokine variants, the neuropeptides, vasoactive intestinal peptide (VIP and pituitary adenylate cyclase activating polypeptide (PACAP-27, and mitochondrial peptides. Upon activation, intracellular domains of FPR2 mediate signaling to G-proteins, which trigger several agonist-dependent signal transduction pathways, including activation of phospholipase C (PLC, protein kinase C (PKC isoforms, the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt pathway, the mitogen-activated protein kinase (MAPK pathway, p38MAPK, as well as the phosphorylation of cytosolic tyrosine kinases, tyrosine kinase receptor transactivation, phosphorylation and nuclear translocation of regulatory transcriptional factors, release of calcium and production of oxidants. FPR2 is an attractive therapeutic target, because of its involvement in a range of normal physiological processes and pathological diseases. Here, we review and discuss the most significant findings on the intracellular pathways and on the cross-communication between FPR2 and tyrosine kinase receptors triggered by different FPR2

  2. Parathyroid hormone-related protein in preterm human milk.

    Science.gov (United States)

    Lubetzky, Ronit; Weisman, Yosef; Dollberg, Shaul; Herman, Lea; Mandel, Dror

    2010-04-01

    Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. High concentrations of PTHrP are found in human breastmilk of mothers of term-infants. It is not known whether PTHrP is excreted in preterm human milk. This study tested the hypothesis that PTHrP concentrations in milk obtained from mothers of preterm infants are similar to those found in milk from mothers of term infants. We collected samples of expressed human milk obtained from 27 mothers of preterm infants (27-34 weeks' gestation) and from 16 mothers of full-term infants. Samples were collected within the first 72 hours postpartum (colostrum) and again at 1 and 2 weeks postpartum. PTHrP concentrations in these samples were measured by two-site immunoradiometric assay. PTHrP concentrations were significantly higher in samples obtained after 1 week postpartum than in samples obtained during the first 72 hours of life in breastmilk obtained from mothers of both term and preterm infants (P milk. PTHrP concentrations after 2 weeks of lactation were significantly higher in samples obtained from mothers of term infants (P milk expressed by mothers of preterm infants contains amounts of PTHrP similar to those measured in milk expressed by mothers of term infants.

  3. Shared fine specificity between T-cell receptors and an antibody recognizing a peptide/major histocompatibility class I complex

    DEFF Research Database (Denmark)

    Stryhn, A; Andersen, P S; Pedersen, L O

    1996-01-01

    Cytotoxic T cells recognize mosaic structures consisting of target peptides embedded within self-major histocompatibility complex (MHC) class I molecules. This structure has been described in great detail for several peptide-MHC complexes. In contrast, how T-cell receptors recognize peptide-MHC c...

  4. Structure of the nociceptin/orphanin FQ receptor in complex with a peptide mimetic

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Aaron A.; Liu, Wei; Chun, Eugene; Katritch, Vsevolod; Wu, Huixian; Vardy, Eyal; Huang, Xi-Ping; Trapella, Claudio; Guerrini, Remo; Calo, Girolamo; Roth, Bryan L.; Cherezov, Vadim; Stevens, Raymond C. (Ferrara); (Scripps); (UNC)

    2012-07-11

    Members of the opioid receptor family of G-protein-coupled receptors (GPCRs) are found throughout the peripheral and central nervous system, where they have key roles in nociception and analgesia. Unlike the 'classical' opioid receptors, {delta}, {kappa} and {mu} ({delta}-OR, {kappa}-OR and {mu}-OR), which were delineated by pharmacological criteria in the 1970s and 1980s, the nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP, also known as ORL-1) was discovered relatively recently by molecular cloning and characterization of an orphan GPCR. Although it shares high sequence similarity with classical opioid GPCR subtypes ({approx}60%), NOP has a markedly distinct pharmacology, featuring activation by the endogenous peptide N/OFQ, and unique selectivity for exogenous ligands. Here we report the crystal structure of human NOP, solved in complex with the peptide mimetic antagonist compound-24 (C-24) (ref. 4), revealing atomic details of ligand-receptor recognition and selectivity. Compound-24 mimics the first four amino-terminal residues of the NOP-selective peptide antagonist UFP-101, a close derivative of N/OFQ, and provides important clues to the binding of these peptides. The X-ray structure also shows substantial conformational differences in the pocket regions between NOP and the classical opioid receptors {kappa} (ref. 5) and {mu} (ref. 6), and these are probably due to a small number of residues that vary between these receptors. The NOP-compound-24 structure explains the divergent selectivity profile of NOP and provides a new structural template for the design of NOP ligands.

  5. Molecular identification of a Drosophila G protein-coupled receptor specific for crustacean cardioactive peptide

    DEFF Research Database (Denmark)

    Cazzamali, Giuseppe; Hauser, Frank; Kobberup, Sune

    2003-01-01

    The Drosophila Genome Project website (www.flybase.org) contains the sequence of an annotated gene (CG6111) expected to code for a G protein-coupled receptor. We have cloned this receptor and found that its gene was not correctly predicted, because an annotated neighbouring gene (CG14547) was also...... part of the receptor gene. DNA corresponding to the corrected gene CG6111 was expressed in Chinese hamster ovary cells, where it was found to code for a receptor that could be activated by low concentrations of crustacean cardioactive peptide, which is a neuropeptide also known to occur in Drosophila...... and other insects (EC(50), 5.4 x 10(-10)M). Other known Drosophila neuropeptides, such as adipokinetic hormone, did not activate the receptor. The receptor is expressed in all developmental stages from Drosophila, but only very weakly in larvae. In adult flies, the receptor is mainly expressed in the head...

  6. Structure-activity analysis of synthetic alpha-thrombin-receptor-activating peptides.

    Science.gov (United States)

    Van Obberghen-Schilling, E; Rasmussen, U B; Vouret-Craviari, V; Lentes, K U; Pavirani, A; Pouysségur, J

    1993-06-15

    alpha-Thrombin stimulates G-protein-coupled effectors leading to secretion and aggregation in human platelets, and to a mitogenic response in CCL39 hamster fibroblasts. alpha-Thrombin receptors can be activated by synthetic peptides corresponding to the receptor sequence starting with serine-42, at the proposed cleavage site. We have previously determined that the agonist domain of receptor-activating peptides resides within the five N-terminal residues [Vouret-Craviari, Van Obberghen-Schilling, Rasmussen, Pavirani, Lecocq and Pouysségur (1992) Mol. Biol. Cell. 3, 95-102], although the 7-residue peptide (SFFLRNP) corresponding to the hamster alpha-thrombin receptor was 10 times more potent than the 5-residue peptide for activation of human platelets. In the present study we have analysed the role of individual amino acids in receptor activation by using a series of modified hexa- or hepta-peptides derived from the human alpha-thrombin-receptor sequence. Cellular events examined here include phospholipase C activation, adenylyl cyclase inhibition and DNA synthesis stimulation in non-transformed CCL39 fibroblasts and a tumorigenic variant of that line (A71 cells). Modification of the peptide sequence had similar functional consequence for each of the assays described, indicating that either a unique receptor or pharmacologically indistinguishable receptor subtypes activate distinct G-protein signalling pathways. Furthermore, we found that: (1) the N-terminal serine can be replaced by small or intermediately sized amino acids (+/- hydroxyl groups) without loss of activity. However, its replacement by an aromatic side-chain or omission of the N-terminal amino group severely reduces activity. (2) An aromatic side-chain on the penultimate N-terminal residue appears to play a critical role since phenylalanine in this position can be substituted by tyrosine without complete loss of activity whereas an alanine in its place is not tolerated. (3) Deletion of the first

  7. A novel peptide agonist of formyl-peptide receptor-like 1 (ALX) displays anti-inflammatory and cardioprotective effects.

    Science.gov (United States)

    Hecht, Iris; Rong, Jiang; Sampaio, André L F; Hermesh, Chen; Rutledge, Caleb; Shemesh, Ronen; Toporik, Amir; Beiman, Merav; Dassa, Liat; Niv, Hagit; Cojocaru, Gady; Zauberman, Arie; Rotman, Galit; Perretti, Mauro; Vinten-Johansen, Jakob; Cohen, Yossi

    2009-02-01

    Activation of the formyl-peptide receptor-like (FPRL) 1 pathway has recently gained high recognition for its significance in therapy of inflammatory diseases. Agonism at FPRL1 affords a beneficial effect in animal models of acute inflammatory conditions, as well as in chronic inflammatory diseases. TIPMFVPESTSKLQKFTSWFM-amide (CGEN-855A) is a novel 21-amino acid peptide agonist for FPRL1 and also activates FPRL2. CGEN-855A was discovered using a computational platform designed to predict novel G protein-coupled receptor peptide agonists cleaved from secreted proteins by convertase proteolysis. In vivo, CGEN-855A displays anti-inflammatory activity manifested as 50% inhibition of polymorphonuclear neutrophil (PMN) recruitment to inflamed air pouch and provides protection against ischemia-reperfusion-mediated injury to the myocardium in both murine and rat models (36 and 25% reduction in infarct size, respectively). Both these activities are accompanied by inhibition of PMN recruitment to the injured organ. The secretion of inflammatory cytokines, including interleukin (IL)-6, IL-1beta, and tumor necrosis factor-alpha, was not affected upon incubation of human peripheral blood mononuclear cells with CGEN-855A, whereas IL-8 secretion was elevated up to 2-fold upon treatment with the highest CGEN-855A dose only. Collectively, these new data support a potential role for CGEN-855A in the treatment of reperfusion-mediated injury and in other acute and chronic inflammatory conditions.

  8. The relaxin family peptide receptors and their ligands : new developments and paradigms in the evolution from jawless fish to mammals

    NARCIS (Netherlands)

    Yegorov, Sergey; Bogerd, Jan; Good, Sara V

    2014-01-01

    Relaxin family peptide receptors (Rxfps) and their ligands, relaxin (Rln) and insulin-like (Insl) peptides, are broadly implicated in the regulation of reproductive and neuroendocrine processes in mammals. Most placental mammals harbour genes for four receptors, namely rxfp1, rxfp2, rxfp3 and rxfp4.

  9. Inhibition of Chondrocyte Hypertrophy of Osteoarthritis by Disruptor Peptide

    Science.gov (United States)

    2017-07-01

    ultimate human subject testing. 2. KEYWORDS: Osteoarthritis Parathyroid hormone-related protein PTH receptor -catenin Cell signaling...To further verify our results, we will repeat the experiments with mouse bone marrow-derived mesenchymal stem cell differentiation to chondrocytes...AWARD NUMBER: W81XWH-16-1-0325 TITLE: Inhibition of Chondrocyte Hypertrophy of Osteoarthritis by Disruptor Peptide PRINCIPAL INVESTIGATOR: Bin

  10. Design and development of receptor-avid peptide conjugates for in-vivo targeting of cancer

    Science.gov (United States)

    Volkert, Wynn A.; Hoffman, Timothy J.

    1999-07-01

    Radiometallated peptides that exhibit high specificity for cognate receptors over expressed on cancer cells offer important potential as site-directed diagnostic and therapeutic radiopharmaceutical. The formation of effective radioactive drugs for specific in vivo targeting of cancerous tumors is being facilitated by the integration of novel chelation strategies and receptor-avid derivatives. Significant efforts are being made to design Technetium-99m labeled for diagnostic imaging of cancerous tumors for use in conjunction with Single Photon Emission Tomography instrumentation in nuclear medicine. Receptor avid radiopharmaceutical are also being developed that utilize other radionuclides for imaging and therapeutic applications. Despite the technological challenges that must be overcome, radiolabeled receptor avid peptide conjugates are providing promising site-directed targeting agents for the assessment and treatment of cancerous tumors in humans.

  11. Umami-bitter interactions: the suppression of bitterness by umami peptides via human bitter taste receptor.

    Science.gov (United States)

    Kim, Min Jung; Son, Hee Jin; Kim, Yiseul; Misaka, Takumi; Rhyu, Mee-Ra

    2015-01-09

    Taste-taste interactions often showed in human psychophysical studies. Considering that each tastant in foodstuffs individually stimulates its responsible gustatory systems to elicit relevant taste modalities, taste-taste interaction should be performed in taste receptor cell-based assay. While umami substances have been proposed to suppress the bitterness of various chemicals in human sensory evaluation, the bitter-umami interaction has not been explored in bitter taste receptors, TAS2Rs. We investigated umami-bitter taste interactions by presenting umami peptides with bitter substance (salicin) on Ca(2+)-flux signaling assay using hTAS2R16-expressing cells. Five representative umami peptides (Glu-Asp, Glu-Glu, Glu-Ser, Asp-Glu-Ser, and Glu-Gly-Ser) derived from soybean markedly attenuated the salicin-induced intracellular calcium influx in a time-dependent manner, respectively, while Gly-Gly, a tasteless peptide did not. The efficacies of Glu-Glu suppressing salicin-induced activation of hTAS2R16 were higher than that of probenecid, a specific antagonist of hTAS2R16. According to Ca(2+)-flux signaling assay using the mixtures of salicin and umami peptides, all five umami peptides suppressed salicin-induced intracellular calcium influx in a noncompetitive manner. These results may provide evidence that umami peptides suppress bitter taste via bitter taste receptor(s). This is the first report which defines the interaction between bitter and umami taste in taste receptor level. Copyright © 2014. Published by Elsevier Inc.

  12. Umami Receptor Activation Increases Duodenal Bicarbonate Secretion via Glucagon-Like Peptide-2 Release in Rats

    OpenAIRE

    Wang, Joon-Ho; Inoue, Takuya; Higashiyama, Masaaki; Guth, Paul H.; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2011-01-01

    Luminal nutrient chemosensing during meal ingestion is mediated by intestinal endocrine cells, which regulate secretion and motility via the release of gut hormones. We have reported that luminal coperfusion of l-Glu and IMP, common condiments providing the umami or proteinaceous taste, synergistically increases duodenal bicarbonate secretion (DBS) possibly via taste receptor heterodimers, taste receptor type 1, member 1 (T1R1)/R3. We hypothesized that glucose-dependent insulinotropic peptide...

  13. Insulin Mimetic Peptide Disrupts the Primary Binding Site of the Insulin Receptor.

    Science.gov (United States)

    Lawrence, Callum F; Margetts, Mai B; Menting, John G; Smith, Nicholas A; Smith, Brian J; Ward, Colin W; Lawrence, Michael C

    2016-07-22

    Sets of synthetic peptides that interact with the insulin receptor ectodomain have been discovered by phage display and reported in the literature. These peptides were grouped into three classes termed Site 1, Site 2, and Site 3 based on their mutual competition of binding to the receptor. Further refinement has yielded, in particular, a 36-residue Site 2-Site 1 fusion peptide, S519, that binds the insulin receptor with subnanomolar affinity and exhibits agonist activity in both lipogenesis and glucose uptake assays. Here, we report three-dimensional crystallographic detail of the interaction of the C-terminal, 16-residue Site 1 component (S519C16) of S519 with the first leucine-rich repeat domain (L1) of the insulin receptor. Our structure shows that S519C16 binds to the same site on the L1 surface as that occupied by a critical component of the primary binding site, namely the helical C-terminal segment of the insulin receptor α-chain (termed αCT). In particular, the two phenylalanine residues within the FYXWF motif of S519C16 are seen to engage the insulin receptor L1 domain surface in a fashion almost identical to the respective αCT residues Phe(701) and Phe(705) The structure provides a platform for the further development of peptidic and/or small molecule agents directed toward the insulin receptor and/or the type 1 insulin-like growth factor receptor. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Analysis of gastrin-releasing peptide gene and gastrin-releasing peptide receptor gene in patients with agoraphobia.

    Science.gov (United States)

    Zimmermann, Katrin; Görgens, Heike; Bräuer, David; Einsle, Franziska; Noack, Barbara; von Kannen, Stephanie; Grossmann, Maria; Hoyer, Jürgen; Strobel, Alexander; Köllner, Volker; Weidner, Kerstin; Ziegler, Andreas; Hemmelmann, Claudia; Schackert, Hans K

    2014-10-01

    A gastrin-releasing peptide receptor (GRPR) knock-out mouse model provided evidence that the gastrin-releasing peptide (GRP) and its neural circuitry operate as a negative feedback-loop regulating fear, suggesting a novel candidate mechanism contributing to individual differences in fear-conditioning and associated psychiatric disorders such as agoraphobia with/without panic disorder. Studies in humans, however, provided inconclusive evidence on the association of GRP and GRPR variations in agoraphobia with/without panic disorder. Based on these findings, we investigated whether GRP and GRPR variants are associated with agoraphobia. Mental disorders were assessed via the Munich-Composite International Diagnostic Interview (M-CIDI) in 95 patients with agoraphobia with/without panic disorder and 119 controls without any mental disorders. A complete sequence analysis of GRP and GRPR was performed in all participants. We found no association of 16 GRP and 7 GRPR variants with agoraphobia with/without panic disorder.

  15. Pressure-driven fast reaction and recovery of peptide receptor for an electronic nose application

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Yong Kyoung [Department of Electrical Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Center for Biomicrosystems, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Sang-Myung [Department of Chemical Engineering, Kangwon National University, Kangwon-do 200-701 (Korea, Republic of); Chae, Myung-Sic; Yoon Kang, Ji; Song Kim, Tae; Seon Hwang, Kyo, E-mail: kshwang@kist.re.kr, E-mail: jhlee@kw.ac.kr [Center for Biomicrosystems, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Hoon Lee, Jeong, E-mail: kshwang@kist.re.kr, E-mail: jhlee@kw.ac.kr [Department of Electrical Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

    2014-02-24

    Combining a highly sensitive sensor platform with highly selective recognition elements is essential for micro/nanotechnology-based electronic nose applications. Particularly, the regeneration sensor surface and its conditions are key issues for practical e-nose applications. We propose a highly sensitive piezoelectric-driven microcantilever array chip with highly selective peptide receptors. By utilizing the peptide receptor, which was discovered by a phase display screening process, we immobilized a dinitrotoluene (DNT) specific peptide as well as a DNT nonspecific peptide on the surface of the cantilever array. The delivery of DNT gas via pressure-driven flow led to a greater instant response of ∼30 Hz, compared to diffusion only (∼15 Hz for 15 h). Using a simple pressure-driven air flow of ∼50 sccm, we confirmed that a ratio of ∼70% of the specific-bounded sites from DNT gas molecules could be regenerated, showing re-usability of the peptide receptor in on-site monitoring for electronic nose applications.

  16. Atrial natriuretic peptide production and natriuretic peptide receptors in the human uterus and their effect on myometrial relaxation.

    Science.gov (United States)

    Cootauco, Alice C; Murphy, Jamie D; Maleski, Jerome; Blakemore, Karin J; Slodzinski, Martin K

    2008-10-01

    The objective of the study was to identify the effect of atrial natriuretic peptide (ANP) on uterine contractility, production of ANP, and natriuretic peptide receptor (NPR) expression in human myometrial tissue. In an institutional review board-approved study, gravid human myometrium was obtained from patients undergoing cesarean section. Uterine contractility was examined using isometric force tension studies. After regular uterine contractions were obtained with oxytocin, ANP was added in increasing concentrations. ANP concentration was measured from myometrial tissue using radioimmunoassay (RIA). Primary myometrial cell culture was performed and treated with nifedipine vs oxytocin. RIA was performed on these cells and the cell culture media. Western blot analysis was performed on uterine tissue samples for natriuretic peptide receptors. With increasing concentration of ANP (starting at 3 pM), myometrial contraction frequency decreased. ANP was identified in primary cultured myometrial cells and cell culture media. Myometrial ANP concentration increased with advancing gestational age. The concentration of ANP decreased within myometrial cells treated with oxytocin. The amount of ANP in the cell culture media increased from cells treated with nifedipine. Western blot identified NPR-A, -B, and -C in myometrial tissue. NPR-A expression was significantly increased in preterm samples. ANP has a dose dependent effect on uterine relaxation. ANP is present in human myometrial cells and appears to be secreted by myometrial cells. The concentration of ANP may vary with gestational age and modulators of uterine contractility. NPR-A, -B, and -C receptor proteins are present in myometrial tissue. NPR-A levels may correlate with gestational age.

  17. Whole Body Activity Retentions in the Peptide Receptor Radionuclide Therapy with Lu-177

    NARCIS (Netherlands)

    Liu, B.

    2013-01-01

    The patients with the neuroendocrine tumours (liver, spleen, etc.) often need treatment by the Peptide Receptor Radionuclide Therapy with 177Lu. The amount of 177Lu activity in the body of patients has to be known accurately for assessment of the dosimetry and for evaluation of the effectiveness of

  18. Effect of the calcitonin gene-related peptide (CGRP) receptor antagonist telcagepant in human cranial arteries

    NARCIS (Netherlands)

    L. Edvinsson (Lars); K.Y. Chan (Kayi); S. Eftekhari; E. Nilsson (Elisabeth); R. de Vries (René); H. Säveland (Hans); C.M.F. Dirven (Clemens); A.H.J. Danser (Jan)

    2010-01-01

    textabstractIntroduction: Calcitonin gene-related peptide (CGRP) is a neuronal messenger in intracranial sensory nerves and is considered to play a significant role in migraine pathophysiology. Materials and methods: We investigated the effect of the CGRP receptor antagonist, telcagepant, on

  19. Effects of glucagon-like peptide-1 (GLP-1) receptor agonists on cardiovascular risk factors

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Vilsbøll, Tina; Knop, Filip K

    2017-01-01

    trials for diabetes therapies. To determine if different glucagon-like peptide-1 receptor agonists (GLP-1RAs) had varying effects on these CV risk factors, we reviewed 16 head-to-head trials directly comparing GLP-1RAs that included at least one of the five factors. Few trials reported statistical...

  20. Mu-opioid peptide (MOP) and nociceptin/orphanin FQ peptide (NOP) receptor activation both contribute to the discriminative stimulus properties of cebranopadol in the rat.

    Science.gov (United States)

    Tzschentke, Thomas M; Rutten, Kris

    2018-02-01

    The novel potent analgesic cebranopadol is an agonist at nociceptin/orphanin FQ peptide (NOP) and classical opioid receptors, with the highest in-vitro activity at NOP and mu-opioid peptide (MOP) receptors, and somewhat lower activity at kappa-opioid peptide (KOP) and delta-opioid peptide (DOP) receptors. We addressed the question of which of these pharmacological activities contribute to the stimulus properties of cebranopadol using a rat drug discrimination procedure. First, cebranopadol was tested in generalization tests against a morphine cue, including receptor-specific antagonism. Second, cebranopadol was established as a cue, and MOP, NOP, KOP and DOP receptor-selective agonists were tested in generalization tests. Third, cebranopadol in combination with receptor-selective antagonists was tested against the cebranopadol cue. Cebranopadol generalized to the morphine cue. Full generalization was only seen at clearly supra-analgesic doses. The effect of cebranopadol was reduced by naloxone, but was enhanced by the NOP receptor antagonist J-113397. In cebranopadol-trained rats, cebranopadol as well as morphine produced generalization. A NOP receptor agonist did not, while a DOP receptor agonist and a KOP receptor agonist weakly generalized to the cebranopadol cue. Conversely, generalization of cebranopadol was reduced by naloxone and J-113397, but not by a DOP or a KOP receptor antagonist. These results suggest a contribution of MOP receptor activity and a relative lack of contribution of DOP and KOP receptor activity to cebranopadol's stimulus properties. The findings regarding the contribution of NOP receptor activity were equivocal, but interestingly, the morphine-like stimulus property of cebranopadol appears to be reduced by its intrinsic NOP receptor activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Human Leukocyte Antigen F Presents Peptides and Regulates Immunity through Interactions with NK Cell Receptors.

    Science.gov (United States)

    Dulberger, Charles L; McMurtrey, Curtis P; Hölzemer, Angelique; Neu, Karlynn E; Liu, Victor; Steinbach, Adriana M; Garcia-Beltran, Wilfredo F; Sulak, Michael; Jabri, Bana; Lynch, Vincent J; Altfeld, Marcus; Hildebrand, William H; Adams, Erin J

    2017-06-20

    Evidence is mounting that the major histocompatibility complex (MHC) molecule HLA-F (human leukocyte antigen F) regulates the immune system in pregnancy, infection, and autoimmunity by signaling through NK cell receptors (NKRs). We present structural, biochemical, and evolutionary analyses demonstrating that HLA-F presents peptides of unconventional length dictated by a newly arisen mutation (R62W) that has produced an open-ended groove accommodating particularly long peptides. Compared to empty HLA-F open conformers (OCs), HLA-F tetramers bound with human-derived peptides differentially stained leukocytes, suggesting peptide-dependent engagement. Our in vitro studies confirm that NKRs differentiate between peptide-bound and peptide-free HLA-F. The complex structure of peptide-loaded β2m-HLA-F bound to the inhibitory LIR1 revealed similarities to high-affinity recognition of the viral MHC-I mimic UL18 and a docking strategy that relies on contacts with HLA-F as well as β2m, thus precluding binding to HLA-F OCs. These findings provide a biochemical framework to understand how HLA-F could regulate immunity via interactions with NKRs. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. The Arabidopsis flagellin receptor FLS2 mediates the perception of Xanthomonas Ax21 secreted peptides.

    Science.gov (United States)

    Danna, Cristian H; Millet, Yves A; Koller, Teresa; Han, Sang-Wook; Bent, Andrew F; Ronald, Pamela C; Ausubel, Frederick M

    2011-05-31

    Detection of microbes by plants relies in part on an array of pattern-recognition receptors that recognize conserved microbial signatures, so-called "microbe-associated molecular patterns." The Arabidopsis thaliana receptor-like kinase FLS2 is the pattern-recognition receptor for bacterial flagellin. Similarly to FLS2, the rice transmembrane protein XA21 is the receptor for the sulfated form of the Xanthomonas oryzae pv. oryzae secreted protein Ax21. Here we show that Ax21-derived peptides activate Arabidopsis immunity, triggering responses similar to those elicited by flagellin, including an oxidative burst, induction of defense-response genes, and enhanced resistance to bacterial pathogens. To identify Arabidopsis Xa21 functional homologs, we used a reverse genetics approach to screen T-DNA insertion mutants corresponding to all 47 of the Arabidopsis genes encoding non-RD kinases belonging to the interleukin-1 receptor-associated kinase (IRAK) family. Surprisingly, among all of these mutant lines, only fls2 mutants exhibited a significant loss of response to Ax21-derived peptides. Ax21 peptides also failed to activate defense-related responses in an fls2-24 mutant that does not bind Flg22. Moreover, a Flg22Δ2 variant of Flg22 that binds to FLS2 but does not activate FLS2-mediated signaling suppressed Ax21-derived peptide signaling, indicating mutually exclusive perception of Flg22 or Ax21 peptides by FLS2. The data indicate that FLS2 functions beyond flagellin perception to detect other microbe-associated molecular patterns.

  3. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor.

    Directory of Open Access Journals (Sweden)

    Yingying Cai

    Full Text Available Family B G protein-coupled receptors (GPCRs play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1 receptor (GLP1R, whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.

  4. Calcitonin gene-related peptide (CGRP receptors are important to maintain cerebrovascular reactivity in chronic hypertension.

    Directory of Open Access Journals (Sweden)

    Zhenghui Wang

    Full Text Available Cerebral blood flow autoregulation (CA shifts to higher blood pressures in chronic hypertensive patients, which increases their risk for brain damage. Although cerebral vascular smooth muscle cells express the potent vasodilatatory peptides calcitonin gene-related peptide (CGRP and adrenomedullin (AM and their receptors (calcitonin receptor-like receptor (Calclr, receptor-modifying proteins (RAMP 1 and 2, their contribution to CA during chronic hypertension is poorly understood. Here we report that chronic (10 weeks hypertensive (one-kidney-one-clip-method mice overexpressing the Calclr in smooth muscle cells (CLR-tg, which increases the natural sensitivity of the brain vasculature to CGRP and AM show significantly better blood pressure drop-induced cerebrovascular reactivity than wt controls. Compared to sham mice, this was paralleled by increased cerebral CGRP-binding sites (receptor autoradiography, significantly in CLR-tg but not wt mice. AM-binding sites remained unchanged. Whereas hypertension did not alter RAMP-1 expression (droplet digital (dd PCR in either mouse line, RAMP-2 expression dropped significantly in both mouse lines by about 65%. Moreover, in wt only Calclr expression was reduced by about 70% parallel to an increase of smooth muscle actin (Acta2 expression. Thus, chronic hypertension induces a stoichiometric shift between CGRP and AM receptors in favor of the CGRP receptor. However, the parallel reduction of Calclr expression observed in wt mice but not CLR-tg mice appears to be a key mechanism in chronic hypertension impairing cerebrovascular reactivity.

  5. Atrial natriuretic peptide/natriuretic peptide receptor A (ANP/NPRA) signaling pathway: a potential therapeutic target for allergic asthma.

    Science.gov (United States)

    Ma, Libing; Xiang, Xudong

    2011-11-01

    Allergic asthma is a chronic inflammatory disease of airway and immune disorder is an acknowledged mechanism. Numerous data demonstrate Th1/Th2 cells play an important role in the development of allergic asthma. Atrial natriuretic peptide (ANP) is a multifunctional hormone secreted by cardiac atria, lung, and so forth, which has been recognized for several decades due to its general effects on cardiovascular system, and natriuretic peptide receptor A (NPRA) is the major effecting receptor for ANP. In recent years, more and more studies suggest that ANP/NPRA signaling pathway is implicated in modulation of immnue and inflammatory reaction. Moreover, there are some reports about significant changes of ANP production in peripheral blood from asthmatics in acute exacerbation compared with patients during the remission and the healthy. Nevertheless, it is unknown that why ANP shows an observable change and what role ANP plays in asthma until now. We propose that ANP/NPRA signaling pathway is involved in immune dysfunction and airway inflammation of allergic asthma based on our experimental results, which suggests ANP/NPRA signaling pathway may be a potential therapeutic target for allergic asthma. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Atypical signaling and functional desensitization response of MAS receptor to peptide ligands.

    Directory of Open Access Journals (Sweden)

    Kalyan C Tirupula

    Full Text Available MAS is a G protein-coupled receptor (GPCR implicated in multiple physiological processes. Several physiological peptide ligands such as angiotensin-(1-7, angiotensin fragments and neuropeptide FF (NPFF are reported to act on MAS. Studies of conventional G protein signaling and receptor desensitization upon stimulation of MAS with the peptide ligands are limited so far. Therefore, we systematically analyzed G protein signals activated by the peptide ligands. MAS-selective non-peptide ligands that were previously shown to activate G proteins were used as controls for comparison on a common cell based assay platform. Activation of MAS by the non-peptide agonist (1 increased intracellular calcium and D-myo-inositol-1-phosphate (IP1 levels which are indicative of the activation of classical Gαq-phospholipase C signaling pathways, (2 decreased Gαi mediated cAMP levels and (3 stimulated Gα12-dependent expression of luciferase reporter. In all these assays, MAS exhibited strong constitutive activity that was inhibited by the non-peptide inverse agonist. Further, in the calcium response assay, MAS was resistant to stimulation by a second dose of the non-peptide agonist after the first activation has waned suggesting functional desensitization. In contrast, activation of MAS by the peptide ligand NPFF initiated a rapid rise in intracellular calcium with very weak IP1 accumulation which is unlike classical Gαq-phospholipase C signaling pathway. NPFF only weakly stimulated MAS-mediated activation of Gα12 and Gαi signaling pathways. Furthermore, unlike non-peptide agonist-activated MAS, NPFF-activated MAS could be readily re-stimulated the second time by the agonists. Functional assays with key ligand binding MAS mutants suggest that NPFF and non-peptide ligands bind to overlapping regions. Angiotensin-(1-7 and other angiotensin fragments weakly potentiated an NPFF-like calcium response at non-physiological concentrations (≥100 µM. Overall, our data

  7. Atypical signaling and functional desensitization response of MAS receptor to peptide ligands.

    Science.gov (United States)

    Tirupula, Kalyan C; Desnoyer, Russell; Speth, Robert C; Karnik, Sadashiva S

    2014-01-01

    MAS is a G protein-coupled receptor (GPCR) implicated in multiple physiological processes. Several physiological peptide ligands such as angiotensin-(1-7), angiotensin fragments and neuropeptide FF (NPFF) are reported to act on MAS. Studies of conventional G protein signaling and receptor desensitization upon stimulation of MAS with the peptide ligands are limited so far. Therefore, we systematically analyzed G protein signals activated by the peptide ligands. MAS-selective non-peptide ligands that were previously shown to activate G proteins were used as controls for comparison on a common cell based assay platform. Activation of MAS by the non-peptide agonist (1) increased intracellular calcium and D-myo-inositol-1-phosphate (IP1) levels which are indicative of the activation of classical Gαq-phospholipase C signaling pathways, (2) decreased Gαi mediated cAMP levels and (3) stimulated Gα12-dependent expression of luciferase reporter. In all these assays, MAS exhibited strong constitutive activity that was inhibited by the non-peptide inverse agonist. Further, in the calcium response assay, MAS was resistant to stimulation by a second dose of the non-peptide agonist after the first activation has waned suggesting functional desensitization. In contrast, activation of MAS by the peptide ligand NPFF initiated a rapid rise in intracellular calcium with very weak IP1 accumulation which is unlike classical Gαq-phospholipase C signaling pathway. NPFF only weakly stimulated MAS-mediated activation of Gα12 and Gαi signaling pathways. Furthermore, unlike non-peptide agonist-activated MAS, NPFF-activated MAS could be readily re-stimulated the second time by the agonists. Functional assays with key ligand binding MAS mutants suggest that NPFF and non-peptide ligands bind to overlapping regions. Angiotensin-(1-7) and other angiotensin fragments weakly potentiated an NPFF-like calcium response at non-physiological concentrations (≥100 µM). Overall, our data suggest

  8. Pleurocidin, a novel antimicrobial peptide, induces human mast cell activation through the FPRL1 receptor.

    Science.gov (United States)

    Pundir, P; Catalli, A; Leggiadro, C; Douglas, S E; Kulka, M

    2014-01-01

    Pleurocidins are a novel family of α-helical cationic antimicrobial peptides (CAPs) that are structurally and functionally similar to cathelicidins, one of the major CAP families. As cathelicidins stimulate mast cell chemotaxis and mediator release, we postulated that pleurocidins similarly activate mast cells. A screen of 20 pleurocidin peptides revealed that some were capable of degranulating the human mast cell line LAD2 (Laboratory of Allergic Diseases 2). Pleurocidin NRC-04 caused LAD2 to adhere, migrate, degranulate, and release cysteinyl leukotrienes and prostaglandin D2. Moreover, pleurocidin increased intracellular Ca(2+) mobilization in mast cells and induced the production of proinflammatory chemokines such as monocyte chemotactic protein-1/C-C motif chemokine ligand 2 (CCL2) and macrophage inflammatory protein-1β/CCL4. Our evaluation of possible cellular mechanisms suggested that G proteins, phosphoinositol-3 kinase (PI3K), phospholipase C (PLC), and phosphokinase C (PKC) were involved in pleurocidin-induced mast cell activation as evidenced by the inhibitory effects of pertussis toxin (G protein inhibitor), wortmanin (PI3K inhibitor), U-73122 (PLC inhibitor), and Ro-31-8220 (PKC inhibitor), respectively. We also found that human mast cells expressed the N-formyl-peptide receptor 1 (FPRL1) receptor and FPRL1-specific inhibitor affected pleurocidin-mediated activation of mast cell. Our finding that the novel CAP pleurocidin activated human mast cell through G protein-coupled receptor signaling suggests that this peptide might have immunomodulatory functions.

  9. The Toxicity of a Chemically Synthesized Peptide Derived from Non-Integrin Platelet Collagen Receptors

    Directory of Open Access Journals (Sweden)

    Thomas M. Chiang

    2008-01-01

    Full Text Available A chemically synthesized peptide derived from platelet non-integrin collagen receptor has been shown to be an effective agent for inhibiting collagen-induced platelet aggregation and adhesion of washed radiolabeled platelets onto natural matrices and collagen coated microtiter plates. In order to be a therapeutic agent, we have used a cell culturing system and an animal model to test its cytotoxicities. In cell culture experiments, the peptide is not toxic to MEG-01, a megakaryoblastic cell line. Prior to performing experiments in rats, the existence of both platelet type I and type III collagen receptors and its functional roles in rat platelets had to be established. In this investigation, we report that rat platelets contain both receptors and the cHyB peptide inhibits both type I and type III collagen-induced rat platelet aggregation. In addition, analysis of the rat sera collected at various time intervals following an injection of cHyB into the rat-tail vein, did not show an increase in the activity of key enzymes which indicate tissue and/or organ damage. These results suggest that the cHyB peptide is safe and its development into a potential therapeutic agent for inhibiting thrombi formation is possible.

  10. The Toxicity of a Chemically Synthesized Peptide Derived from Non-Integrin Platelet Collagen Receptors

    Directory of Open Access Journals (Sweden)

    Thomas M. Chiang

    2008-08-01

    Full Text Available A chemically synthesized peptide derived from platelet non-integrin collagen receptor has been shown to be an effective agent for inhibiting collagen-induced platelet aggregation and adhesion of washed radiolabeled platelets onto natural matrices and collagen coated microtiter plates. In order to be a therapeutic agent, we have used a cell culturing system and an animal model to test its cytotoxicities. In cell culture experiments, the peptide is not toxic to MEG-01, a megakaryoblastic cell line. Prior to performing experiments in rats, the existence of both platelet type I and type III collagen receptors and its functional roles in rat platelets had to be established. In this investigation, we report that rat platelets contain both receptors and the cHyB peptide inhibits both type I and type III collagen-induced rat platelet aggregation. In addition, analysis of the rat sera collected at various time intervals following an injection of cHyB into the rat-tail vein, did not show an increase in the activity of key enzymes which indicate tissue and/or organ damage. These results suggest that the cHyB peptide is safe and its development into a potential therapeutic agent for inhibiting thrombi formation is possible.

  11. The Toxicity of a Chemically Synthesized Peptide Derived from Non-Integrin Platelet Collagen Receptors

    Directory of Open Access Journals (Sweden)

    Thomas M. Chiang

    2008-01-01

    Full Text Available A chemically synthesized peptide derived from platelet non-integrin collagen receptor has been shown to be an effective agent for inhibiting collagen-induced platelet aggregation and adhesion of washed radiolabeled platelets onto natural matrices and collagen coated microtiter plates. In order to be a therapeutic agent, we have used a cell culturing system and an animal model to test its cytotoxicities. In cell culture experiments, the peptide is not toxic to MEG-01, a megakaryo-blastic cell line. Prior to performing experiments in rats, the existence of both platelet type I and type III collagen receptors and its functional roles in rat platelets had to be established. In this investigation, we report that rat platelets contain both receptors and the cHyB peptide inhibits both type I and type III collagen-induced rat platelet aggregation. In addition, analysis of the rat sera collected at various time intervals following an injection of cHyB into the rat-tail vein, did not show an increase in the activity of key enzymes which indicate tissue and/or organ damage. These results suggest that the cHyB peptide is safe and its development into a potential therapeutic agent for inhibiting thrombi formation is possible.

  12. The formyl peptide receptor like-1 and scavenger receptor MARCO are involved in glial cell activation in bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Jansen Sandra

    2011-02-01

    Full Text Available Abstract Background Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure mediates activation of the immune response in bacterial infection of the central nervous system (CNS. The chemotactic G-protein-coupled receptor (GPCR formyl-peptide-receptor like-1 (FPRL1 plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD. Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. Methods Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP and Neisseria meningitides (NM. Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2 phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene expression and signal transduction were determined. Results We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between

  13. G-Protein Coupled Receptors Targeted by Analgesic Venom Peptides

    OpenAIRE

    James T. Daniel; Clark, Richard J.

    2017-01-01

    Chronic pain is a complex and debilitating condition associated with a large personal and socioeconomic burden. Current pharmacological approaches to treating chronic pain such as opioids, antidepressants and anticonvulsants exhibit limited efficacy in many patients and are associated with dose-limiting side effects that hinder their clinical use. Therefore, improved strategies for the pharmacological treatment of pathological pain are urgently needed. G-protein coupled receptors (GPCRs) are ...

  14. Functional receptors for atrial natriuretic peptide in the rat mammary gland during lactation.

    Science.gov (United States)

    Cvek, K; Ridderstråle, Y; Gerstberger, R

    1998-05-01

    The present study was undertaken: 1) to localize and characterize atrial natriuretic peptide (ANP) receptors in the rat mammary gland; and 2) to elucidate ANP-induced cellular formation of cyclic GMP (cGMP) and alterations in alveolar morphology during both early and late lactation. Receptor autoradiography, employing rat-specific [125I]ANP as radioligand, demonstrated binding sites in the secretory tissue and larger blood vessels of the mammary gland. Binding of [125I]rANP to membrane fractions was completely displaced by unlabeled ANP and brain natriuretic peptide. C-type natriuretic peptide and cANP(4-23) revealed limited competition with radiolabeled ANP only during early lactation, indicating a more heterogeneous receptor population at that time. Systemically administered ANP induced cGMP formation in the alveolar epithelium, as shown with immunohistochemistry, and increased mammary tissue cGMP concentrations in vivo throughout the lactation period. Image analysis revealed enlargement of alveolar (but not epithelial) cell area after ANP stimulation in late lactation, suggesting altered alveolar filling or myoepithelial cell relaxation. These results indicate that ANP induces biological effects in the rat mammary gland through specific ANP-A receptor interaction with subsequent intracellular cGMP formation. ANP may therefore play a regulatory role in the control of mammary gland blood supply and secretory function.

  15. Ghrelin receptor inverse agonists: identification of an active peptide core and its interaction epitopes on the receptor

    DEFF Research Database (Denmark)

    Holst, Birgitte; Lang, Manja; Brandt, Erik

    2006-01-01

    [D-Arg1,D-Phe5,D-Trp7,9,Leu11]Substance P functions as a low-potency antagonist but a high-potency full inverse agonist on the ghrelin receptor. Through a systematic deletion and substitution analysis of this peptide, the C-terminal carboxyamidated pentapeptide wFwLX was identified as the core...... structure, which itself displayed relatively low inverse agonist potency. Mutational analysis at 17 selected positions in the main ligand-binding crevice of the ghrelin receptor demonstrated that ghrelin apparently interacts only with residues in the middle part of the pocket [i.e., between transmembrane...... upon both AspII:20 and GluIII:09. The identified pharmacophore can possibly serve as the basis for targeted discovery of also nonpeptide inverse agonists for the ghrelin receptor....

  16. Glucagon-like peptide-1 receptors in the brain: controlling food intake and body weight.

    Science.gov (United States)

    Baggio, Laurie L; Drucker, Daniel J

    2014-10-01

    The peptide hormone glucagon-like peptide-1 (GLP-1) enhances glucose-induced insulin secretion and inhibits both gastric emptying and glucagon secretion. GLP-1 receptor (GLP-1R) agonists control glycemia via glucose-dependent mechanisms of action and promote weight loss in obese and diabetic individuals. Nevertheless, the mechanisms and cellular targets transducing the weight loss effects remain unclear. Two recent studies in the JCI provide insight into the neurons responsible for this effect. Sisley et al. reveal that GLP-1R agonist-induced weight loss requires GLP-1Rs in the CNS, while Secher et al. reveal that a small peptide GLP-1R agonist penetrates the brain and activates a subset of GLP-1R-expressing neurons in the arcuate nucleus to produce weight loss. Together, these two studies elucidate pathways that inform strategies coupling GLP-1R signaling to control of body weight in patients with diabetes or obesity.

  17. A peptide antagonist of the ErbB1 receptor inhibits receptor activation, tumor cell growth and migration in vitro and xenograft tumor growth in vivo

    DEFF Research Database (Denmark)

    Xu, Ruodan; Povlsen, Gro Klitgaard; Soroka, Vladislav

    2010-01-01

    The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization...... lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti-cancer...

  18. Decreased glucagon-like peptide 1 receptor expression in endothelial and smooth muscle cells in diabetic db/db mice: TCF7L2 is a possible regulator of the vascular glucagon-like peptide 1 receptor.

    Science.gov (United States)

    Kimura, Tomohiko; Obata, Atsushi; Shimoda, Masashi; Okauchi, Seizo; Hirukawa, Hidenori; Kohara, Kenji; Kinoshita, Tomoe; Nogami, Yuka; Nakanishi, Shuhei; Mune, Tomoatsu; Kaku, Kohei; Kaneto, Hideaki

    2017-11-01

    Incretin signalling is known to prevent the development of arteriosclerosis by relaxation response in endothelial cells via the glucagon-like peptide 1 receptor. It remains unclear, however, whether vascular glucagon-like peptide 1 receptor expression is altered under some conditions. The aim of this study is to examine whether vascular glucagon-like peptide 1 receptor expression is altered by diabetic state as reported in pancreatic β-cells. We used 18-week-old male diabetic db/db mice and control db/m mice. Excised thoracic artery was specifically collected, and vascular endothelial cells were cultured. We compared the glucagon-like peptide 1 receptor expression levels between the db/db and db/m mice. Metabolic parameters were significantly worse in db/db mice. The glucagon-like peptide 1 receptor and transcription factor 7-like 2 expression levels in endothelial and smooth muscle cells were significantly lower in db/db mice. Furthermore, siRNA to transcription factor 7-like 2 decreased the transcription factor 7-like 2 levels and such reduction of the transcription factor 7-like 2 resulted in the downregulation of the glucagon-like peptide 1 receptor expressions in cultured vascular endothelial cells. The glucagon-like peptide 1 receptor expression level was significantly lower under diabetic condition which was accompanied by the reduction of the transcription factor 7-like 2 expression level. Furthermore, the transcription factor 7-like 2 is a possible regulator of the glucagon-like peptide 1 receptor expression in artery as reported in β-cells.

  19. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    DEFF Research Database (Denmark)

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm

    2013-01-01

    patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared......Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted...... towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor...

  20. Diurnal gene expression of lipolytic natriuretic peptide receptors in white adipose tissue

    DEFF Research Database (Denmark)

    Smith, Julie; Fahrenkrug, Jan; Jørgensen, Henrik L

    2015-01-01

    Disruption of the circadian rhythm can lead to obesity and cardiovascular disease. In white adipose tissue, activation of the natriuretic peptide receptors (NPRs) stimulates lipolysis. We have previously shown that natriuretic peptides are expressed in a circadian manner in the heart......, but the temporal expression profile of their cognate receptors has not been examined in white adipose tissue. We therefore collected peri-renal white adipose tissue and serum from WT mice. Tissue mRNA contents of NPRs - NPR-A and NPR-C, the clock genes Per1 and Bmal1, and transcripts involved in lipid metabolism...... were quantified at 4-h intervals: in the diurnal study, mice were exposed to a period of 12 h light followed by 12 h darkness (n=52). In the circadian study, mice were kept in darkness for 24 h (n=47). Concomitant serum concentrations of free fatty acids, glycerol, triglycerides (TGs), and insulin were...

  1. Peptide Phage Display as a Tool for Drug Discovery: Targeting Membrane Receptors

    Directory of Open Access Journals (Sweden)

    Tomaz Bratkovic

    2011-01-01

    Full Text Available Ligands selected from phage-displayed random peptide libraries tend to be directed to biologically relevant sites on the surface of the target protein. Consequently, peptides derived from library screenings often modulate the target protein’s activity in vitro and in vivo and can be used as lead compounds in drug design and as alternatives to antibodies for target validation in both genomics and drug discovery. This review discusses the use of phage display to identify membrane receptor modulators with agonistic or antagonistic activities. Because isolating or producing recombinant membrane proteins for use as target molecules in library screening is often impossible, innovative selection strategies such as panning against whole cells or tissues, recombinant receptor ectodomains, or neutralizing antibodies to endogenous binding partners were devised. Prominent examples from a two-decade history of peptide phage display will be presented, focusing on the design of affinity selection experiments, methods for improving the initial hits, and applications of the identified peptides.

  2. Negative regulation of parathyroid hormone-related protein expression by steroid hormones

    Energy Technology Data Exchange (ETDEWEB)

    Kajitani, Takashi; Tamamori-Adachi, Mimi [Department of Biochemistry, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605 (Japan); Okinaga, Hiroko [Department of Internal Medicine, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605 (Japan); Chikamori, Minoru; Iizuka, Masayoshi [Department of Biochemistry, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605 (Japan); Okazaki, Tomoki, E-mail: okbgeni@med.teikyo-u.ac.jp [Department of Biochemistry, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605 (Japan)

    2011-04-15

    Highlights: {yields} Steroid hormones repress expression of PTHrP in the cell lines where the corresponding nuclear receptors are expressed. {yields} Nuclear receptors are required for suppression of PTHrP expression by steroid hormones, except for androgen receptor. {yields} Androgen-induced suppression of PTHrP expression appears to be mediated by estrogen receptor. -- Abstract: Elevated parathyroid hormone-related protein (PTHrP) is responsible for humoral hypercalcemia of malignancy (HHM), which is of clinical significance in treatment of terminal patients with malignancies. Steroid hormones were known to cause suppression of PTHrP expression. However, detailed studies linking multiple steroid hormones to PTHrP expression are lacking. Here we studied PTHrP expression in response to steroid hormones in four cell lines with excessive PTHrP production. Our study established that steroid hormones negatively regulate PTHrP expression. Vitamin D receptor, estrogen receptor {alpha}, glucocorticoid receptor, and progesterone receptor, were required for repression of PTHrP expression by the cognate ligands. A notable exception was the androgen receptor, which was dispensable for suppression of PTHrP expression in androgen-treated cells. We propose a pathway(s) involving nuclear receptors to suppress PTHrP expression.

  3. Interaction between umami peptide and taste receptor T1R1/T1R3.

    Science.gov (United States)

    Dang, Yali; Gao, Xinchang; Xie, Aiying; Wu, Xueqian; Ma, Fumin

    2014-12-01

    The umami taste receptor is a heterodimer composed of two members of the T1R taste receptor family: T1R1 and T1R3. The homology models of the ligand binding domains of the human umami receptor have been constructed based on crystallographic structures of the taste receptor of the central nervous system. Furthermore, the molecular simulations of the ligand binding domain show that the likely conformation was that T1R1 protein exists in the closed conformation, and T1R3 in the open conformation in the heterodimer. The molecular docking study of T1R1 and T1R3 in complex with four peptides, including Lys-Gly-Asp-Glu-Ser-Leu-Leu-Ala, Ser-Glu-Glu, G1u-Ser, and Asp-Glu-Ser, displayed that the amino acid residue of SER146 and Glu277 in T1R3 may play great roles in the synergism of umami taste. This docking result further validated the robustness of the model. In the paper, binding of umami peptide and the T1R1/T1R3 receptor was first described and the interaction is the base of umami activity theory.

  4. Biochemical and Cellular Specificity of Peptide Inhibitors of G Protein-Coupled Receptor Kinases

    OpenAIRE

    Baameur, Faiza; Hammitt, Richard A.; Friedman, Jacqueline; McMurray, John S.; Clark, Richard B

    2014-01-01

    Identifying novel allosteric inhibitors of G protein-coupled receptor kinases (GRKs) would be of considerable use in limiting both the extent of desensitization of GPCRs as well as downstream positive regulation through GRKs. Several peptides have previously been identified as inhibitors of specific GRKs, but to date there have been few comparisons of the selectivities of these materials on the seven GRKs, modifications to allow cell penetration, or off-target activities. The goal of this stu...

  5. A homeostatic sleep-stabilizing pathway in Drosophila composed of the sex peptide receptor and its ligand, the myoinhibitory peptide.

    Science.gov (United States)

    Oh, Yangkyun; Yoon, Sung-Eun; Zhang, Qi; Chae, Hyo-Seok; Daubnerová, Ivana; Shafer, Orie T; Choe, Joonho; Kim, Young-Joon

    2014-10-01

    Sleep, a reversible quiescent state found in both invertebrate and vertebrate animals, disconnects animals from their environment and is highly regulated for coordination with wakeful activities, such as reproduction. The fruit fly, Drosophila melanogaster, has proven to be a valuable model for studying the regulation of sleep by circadian clock and homeostatic mechanisms. Here, we demonstrate that the sex peptide receptor (SPR) of Drosophila, known for its role in female reproduction, is also important in stabilizing sleep in both males and females. Mutants lacking either the SPR or its central ligand, myoinhibitory peptide (MIP), fall asleep normally, but have difficulty in maintaining a sleep-like state. Our analyses have mapped the SPR sleep function to pigment dispersing factor (pdf) neurons, an arousal center in the insect brain. MIP downregulates intracellular cAMP levels in pdf neurons through the SPR. MIP is released centrally before and during night-time sleep, when the sleep drive is elevated. Sleep deprivation during the night facilitates MIP secretion from specific brain neurons innervating pdf neurons. Moreover, flies lacking either SPR or MIP cannot recover sleep after the night-time sleep deprivation. These results delineate a central neuropeptide circuit that stabilizes the sleep state by feeding a slow-acting inhibitory input into the arousal system and plays an important role in sleep homeostasis.

  6. A homeostatic sleep-stabilizing pathway in Drosophila composed of the sex peptide receptor and its ligand, the myoinhibitory peptide.

    Directory of Open Access Journals (Sweden)

    Yangkyun Oh

    2014-10-01

    Full Text Available Sleep, a reversible quiescent state found in both invertebrate and vertebrate animals, disconnects animals from their environment and is highly regulated for coordination with wakeful activities, such as reproduction. The fruit fly, Drosophila melanogaster, has proven to be a valuable model for studying the regulation of sleep by circadian clock and homeostatic mechanisms. Here, we demonstrate that the sex peptide receptor (SPR of Drosophila, known for its role in female reproduction, is also important in stabilizing sleep in both males and females. Mutants lacking either the SPR or its central ligand, myoinhibitory peptide (MIP, fall asleep normally, but have difficulty in maintaining a sleep-like state. Our analyses have mapped the SPR sleep function to pigment dispersing factor (pdf neurons, an arousal center in the insect brain. MIP downregulates intracellular cAMP levels in pdf neurons through the SPR. MIP is released centrally before and during night-time sleep, when the sleep drive is elevated. Sleep deprivation during the night facilitates MIP secretion from specific brain neurons innervating pdf neurons. Moreover, flies lacking either SPR or MIP cannot recover sleep after the night-time sleep deprivation. These results delineate a central neuropeptide circuit that stabilizes the sleep state by feeding a slow-acting inhibitory input into the arousal system and plays an important role in sleep homeostasis.

  7. Promotion of formyl peptide receptor 1-mediated neutrophil chemotactic migration by antimicrobial peptides isolated from the centipede Scolopendra subspinipes mutilans.

    Science.gov (United States)

    Park, Yoo Jung; Lee, Sung Kyun; Jung, Young Su; Lee, Mingyu; Lee, Ha Young; Kim, Sang Doo; Park, Joon Seong; Koo, JaeHyung; Hwang, Jae Sam; Bae, Yoe-Sik

    2016-09-01

    We investigated the effects of two antimicrobial peptides (AMPs) isolated from Scolopendra subspinipes mutilans on neutrophil activity. Stimulation of mouse neutrophils with the two AMPs elicited chemotactic migration of the cells in a pertussis toxin-sensitive manner. The two AMPs also stimulated activation of ERK and Akt, which contribute to chemotactic migration of neutrophils. We found that AMP-stimulated neutrophil chemotaxis was blocked by a formyl peptide receptor (FPR) 1 antagonist (cyclosporin H); moreover the two AMPs stimulated the chemotactic migration of FPR1-expressing RBL-2H3 cells but not of vector-expressing RBL-2H3 cells. We also found that the two AMPs stimulate neutrophil migration in vivo, and that this effect is blocked in FPR1-deficient mice. Taken together, our results suggest that the two AMPs stimulate neutrophils, leading to chemotactic migration through FPR1, and the two AMPs will be useful for the study of FPR1 signaling and neutrophil activation. [BMB Reports 2016; 49(9): 520-525].

  8. Oxyntomodulin differentially affects glucagon-like peptide-1 receptor beta-arrestin recruitment and signaling through Galpha(s)

    DEFF Research Database (Denmark)

    Jorgensen, Rasmus; Kubale, Valentina; Vrecl, Milka

    2007-01-01

    The glucagon-like peptide (GLP)-1 receptor is a promising target for the treatment of type 2 diabetes and obesity, and there is great interest in characterizing the pharmacology of the GLP-1 receptor and its ligands. In the present report, we have applied bioluminescence resonance energy transfer...... assays to measure agonist-induced recruitment of betaarrestins and G-protein-coupled receptor kinase (GRK) 2 to the GLP-1 receptor in addition to traditional measurements of second messenger generation. The peptide hormone oxyntomodulin is described in the literature as a full agonist on the glucagon...

  9. α-RgIB: A Novel Antagonist Peptide of Neuronal Acetylcholine Receptor Isolated from Conus regius Venom

    Directory of Open Access Journals (Sweden)

    Maria Cristina Vianna Braga

    2013-01-01

    Full Text Available Conus venoms are rich sources of biologically active peptides that act specifically on ionic channels and metabotropic receptors present at the neuromuscular junction, efficiently paralyzing the prey. Each species of Conus may have 50 to 200 uncharacterized bioactive peptides with pharmacological interest. Conus regius is a vermivorous species that inhabits Northeastern Brazilian tropical waters. In this work, we characterized one peptide with activity on neuronal acetylcholine receptor (nAChR. Crude venom was purified by reverse-phase HPLC and selected fractions were screened and sequenced by mass spectrometry, MALDI-ToF, and ESI-Q-ToF, respectively. A new peptide was identified, bearing two disulfide bridges. The novel 2,701 Da peptide belongs to the cysteine framework I, corresponding to the cysteine pattern CC-C-C. The biological activity of the purified peptide was tested by intracranial injection in mice, and it was observed that high concentrations induced hyperactivity in the animals, whereas lower doses caused breathing difficulty. The activity of this peptide was assayed in patch-clamp experiments, on nAChR-rich cells, in whole-cell configuration. The peptide blocked slow rise-time neuronal receptors, probably α3β4 and/or α3β4α5 subtype. According to the nomenclature, the new peptide was designated as α-RgIB.

  10. Identification of potent 11mer glucagon-like peptide-1 receptor agonist peptides with novel C-terminal amino acids: Homohomophenylalanine analogs.

    Science.gov (United States)

    Haque, Tasir S; Lee, Ving G; Riexinger, Douglas; Lei, Ming; Malmstrom, Sarah; Xin, Li; Han, Songping; Mapelli, Claudio; Cooper, Christopher B; Zhang, Ge; Ewing, William R; Krupinski, John

    2010-05-01

    We report the identification of potent agonists of the Glucagon-Like Peptide-1 Receptor (GLP-1R). These compounds are short, 11 amino acid peptides containing several unnatural amino acids, including (in particular) analogs of homohomophenylalanine (hhPhe) at the C-terminal position. Typically the functional activity of the more potent peptides in this class is in the low picomolar range in an in vitro cAMP assay, with one example demonstrating excellent in vivo activity in an ob/ob mouse model of diabetes. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  11. Cell wall trapping of autocrine peptides for human G-protein-coupled receptors on the yeast cell surface.

    Directory of Open Access Journals (Sweden)

    Jun Ishii

    Full Text Available G-protein-coupled receptors (GPCRs regulate a wide variety of physiological processes and are important pharmaceutical targets for drug discovery. Here, we describe a unique concept based on yeast cell-surface display technology to selectively track eligible peptides with agonistic activity for human GPCRs (Cell Wall Trapping of Autocrine Peptides (CWTrAP strategy. In our strategy, individual recombinant yeast cells are able to report autocrine-positive activity for human GPCRs by expressing a candidate peptide fused to an anchoring motif. Following expression and activation, yeast cells trap autocrine peptides onto their cell walls. Because captured peptides are incapable of diffusion, they have no impact on surrounding yeast cells that express the target human GPCR and non-signaling peptides. Therefore, individual yeast cells can assemble the autonomous signaling complex and allow single-cell screening of a yeast population. Our strategy may be applied to identify eligible peptides with agonistic activity for target human GPCRs.

  12. Recognition of core and flanking amino acids of MHC class II-bound peptides by the T cell receptor.

    Science.gov (United States)

    Sant'Angelo, Derek B; Robinson, Eve; Janeway, Charles A; Denzin, Lisa K

    2002-09-01

    CD4 T cells recognize peptides bound to major histocompatibility complex (MHC) class II molecules. Most MHC class II molecules have four binding pockets occupied by amino acids 1, 4, 6, and 9 of the minimal peptide epitope, while the residues at positions 2, 3, 5, 7, and 8 are available to interact with the T cell receptor (TCR). In addition MHC class II bound peptides have flanking residues situated outside of this peptide core. Here we demonstrate that the flanking residues of the conalbumin peptide bound to I-A(k) have no effect on recognition by the D10 TCR. To study the role of peptide flanks for recognition by a second TCR, we determined the MHC and TCR contacting amino acids of the I-A(b) bound Ealpha peptide. The Ealpha peptide is shown to bind I-A(b) using four alanines as anchor residues. TCR recognition of Ealpha peptides with altered flanking residues again suggested that, in general, no specific interactions occurred with the peptide flanks. However, using an HLA-DM-mediated technique to measure peptide binding to MHC class II molecules, we found that the peptide flanking residues contribute substantially to MHC binding.

  13. Multifunctionalized gold nanoparticles with peptides targeted to gastrin-releasing peptide receptor of a tumor cell line.

    NARCIS (Netherlands)

    Hosta-Rigau, L.; Olmedo, I.; Arbiol, J.; Cruz, L.J.; Kogan, M.J.; Albericio, F.

    2010-01-01

    Functionalization of gold nanoparticles (AuNPs) with both a targeting peptide (an analogue of the peptide Bombesin) and a drug peptide ligand (an analogue of the RAF peptide) with the aim of improving selectivity in the delivery of the conjugates as well as the antitumor activity is described.

  14. Glucagon-like peptide-1 receptor overexpression in cancer and its impact on clinical applications

    Directory of Open Access Journals (Sweden)

    Meike eKörner

    2012-12-01

    Full Text Available Peptide hormones of the glucagon-like peptide (GLP family play an increasing clinical role, such as GLP-1 in diabetes therapy. Moreover, GLP receptors are over-expressed in various human tumor types and therefore represent molecular targets for important clinical applications. In particular, virtually all benign insulinomas highly over-express GLP-1 receptors (GLP-1R. Targeting GLP-1R with the stable GLP-1 analogs 111In-DOTA/ DPTA-exendin-4 offers a new approach to successfully localize these small tumors. This non-invasive technique has the potential to replace the invasive localization of insulinomas by selective arterial stimulation and venous sampling. Malignant insulinomas, in contrast to their benign counterparts, express GLP-1R in only one third of the cases, while they more often express the somatostatin type 2 receptors. Importantly, one of the two receptors appears to be always expressed in malignant insulinomas. The GLP-1R overexpression in selected cancers is worth to be kept in mind with regard to the increasing use of GLP-1 analogs for diabetes therapy. While the functional role of GLP-1R in neoplasia is not known yet, it may be safe to monitore patients undergoing GLP-1 therapy carefully.

  15. Combined autoradiographic-immunocytochemical analysis of opioid receptors and opioid peptide neuronal systems in brain

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, M.E.; Khachaturian, H.; Watson, S.J.

    1985-01-01

    Using adjacent section autoradiography-immunocytochemistry, the distribution of (TH)naloxone binding sites was studied in relation to neuronal systems containing (Leu)enkephalin, dynorphin A, or beta-endorphin immunoreactivity in rat brain. Brain sections from formaldehyde-perfused rats show robust specific binding of (TH)naloxone, the pharmacological (mu-like) properties of which appear unaltered. In contrast, specific binding of the delta ligand (TH)D-Ala2,D-Leu5-enkephalin was virtually totally eliminated as a result of formaldehyde perfusion. Using adjacent section analysis, the authors have noted associations between (TH)naloxone binding sites and one, two, or all three opioid systems in different brain regions; however, in some areas, no apparent relationship could be observed. Within regions, the relationship was complex. The complexity of the association between (TH)naloxone binding sites and the multiple opioid systems, and previous reports of co-localization of mu and kappa receptors in rat brain, are inconsistent with a simple-one-to-one relationship between a given opioid precursor and opioid receptor subtype. Instead, since differential processing of the three precursors gives rise to peptides of varying receptor subtype potencies and selectivities, the multiple peptide-receptor relationships may point to a key role of post-translational processing in determining the physiological consequences of opioid neurotransmission.

  16. Structural insight into antibody-mediated antagonism of the Glucagon-like peptide-1 Receptor

    Science.gov (United States)

    Hennen, Stephanie; Kodra, János T.; Soroka, Vladyslav; Krogh, Berit O.; Wu, Xiaoai; Kaastrup, Peter; Ørskov, Cathrine; Rønn, Sif G.; Schluckebier, Gerd; Barbateskovic, Silvia; Gandhi, Prafull S.; Reedtz-Runge, Steffen

    2016-01-01

    The Glucagon-like peptide-1 receptor (GLP-1R) is a member of the class B G protein-coupled receptor (GPCR) family and a well-established target for the treatment of type 2 diabetes. The N-terminal extracellular domain (ECD) of GLP-1R is important for GLP-1 binding and the crystal structure of the GLP-1/ECD complex was reported previously. The first structure of a class B GPCR transmembrane (TM) domain was solved recently, but the full length receptor structure is still not well understood. Here we describe the molecular details of antibody-mediated antagonism of the GLP-1R using both in vitro pharmacology and x-ray crystallography. We showed that the antibody Fab fragment (Fab 3F52) blocked the GLP-1 binding site of the ECD directly and thereby acts as a competitive antagonist of native GLP-1. Interestingly, Fab 3F52 also blocked a short peptide agonist believed to engage primarily the transmembrane and extracellular loop region of GLP-1R, whereas functionality of an allosteric small-molecule agonist was not inhibited. This study has implications for the structural understanding of the GLP-1R and related class B GPCRs, which is important for the development of new and improved therapeutics targeting these receptors. PMID:27196125

  17. Structure, signaling mechanism and regulation of the natriuretic peptide receptor guanylate cyclase.

    Energy Technology Data Exchange (ETDEWEB)

    Misono, K. S.; Philo, J. S.; Arakawa, T.; Ogata, C. M.; Qiu, Y.; Ogawa, H.; Young, H. S. (Biosciences Division); (Univ. of Nevada); (Alliance Protein Labs.)

    2011-06-01

    Atrial natriuretic peptide (ANP) and the homologous B-type natriuretic peptide are cardiac hormones that dilate blood vessels and stimulate natriuresis and diuresis, thereby lowering blood pressure and blood volume. ANP and B-type natriuretic peptide counterbalance the actions of the renin-angiotensin-aldosterone and neurohormonal systems, and play a central role in cardiovascular regulation. These activities are mediated by natriuretic peptide receptor-A (NPRA), a single transmembrane segment, guanylyl cyclase (GC)-linked receptor that occurs as a homodimer. Here, we present an overview of the structure, possible chloride-mediated regulation and signaling mechanism of NPRA and other receptor GCs. Earlier, we determined the crystal structures of the NPRA extracellular domain with and without bound ANP. Their structural comparison has revealed a novel ANP-induced rotation mechanism occurring in the juxtamembrane region that apparently triggers transmembrane signal transduction. More recently, the crystal structures of the dimerized catalytic domain of green algae GC Cyg12 and that of cyanobacterium GC Cya2 have been reported. These structures closely resemble that of the adenylyl cyclase catalytic domain, consisting of a C1 and C2 subdomain heterodimer. Adenylyl cyclase is activated by binding of G{sub s}{alpha} to C2 and the ensuing 7{sup o} rotation of C1 around an axis parallel to the central cleft, thereby inducing the heterodimer to adopt a catalytically active conformation. We speculate that, in NPRA, the ANP-induced rotation of the juxtamembrane domains, transmitted across the transmembrane helices, may induce a similar rotation in each of the dimerized GC catalytic domains, leading to the stimulation of the GC catalytic activity.

  18. Comparative biodistribution of 12 {sup 111}In-labelled gastrin/CCK2 receptor-targeting peptides

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Joosten, Lieke; Eek, Annemarie; Roosenburg, Susan; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Maina, Theodosia [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Maecke, Helmut [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Aloj, Luigi [Fondazione ' ' G. Pascale' ' , Department of Nuclear Medicine, Istituto Nazionale Tumouri, Naples (Italy); Guggenberg, Elisabeth von [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Sosabowski, Jane K. [Queen Mary, University of London, Centre for Molecular Oncology and Imaging, Institute of Cancer, Barts and The London School of Medicine and Dentistry, London (United Kingdom); Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Reubi, Jean-Claude [University of Berne, Institute of Pathology, Berne (Switzerland)

    2011-08-15

    Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed and some have been tested in patients. Here we aimed to compare the in vivo tumour targeting properties of 12 {sup 111}In-labelled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated gastrin/CCK2 receptor-binding peptides. Two CCK8-based peptides and ten gastrin-based peptide analogues were tested. All peptides were conjugated with DOTA and labelled with {sup 111}In. Biodistribution studies were performed in mice with subcutaneous CCK2/gastrin receptor-expressing tumours and with receptor-negative tumours contralaterally. Biodistribution was studied by counting dissected tissues at 1 and 4 h after injection. Both the CCK analogues displayed relatively low tumour uptake (approximately 2.5%ID/g) as compared to minigastrin analogues. Two linear minigastrin peptides (MG0 and sargastrin) displayed moderate tumour uptake at both 1 and 4 h after injection, but also very high kidney uptake (both higher than 48%ID/g). The linear MG11, lacking the penta-Glu sequence, showed lower tumour uptake and also low kidney uptake. Varying the N-terminal Glu residues in the minigastrin analogues led to improved tumour targeting properties, with PP-F11 displaying the optimal biodistribution. Besides the monomeric linear peptides, a cyclized peptide and a divalent peptide were tested. Based on these studies, optimal peptides for peptide receptor radionuclide targeting of CCK2/gastrin receptor-expressing tumours were the linear minigastrin analogue with six D-Glu residues (PP-F11), the divalent analogue MGD5 and the cyclic peptide cyclo-MG1. These peptides combined high tumour uptake with low kidney retention, and may

  19. Distribution of vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, nitric oxide synthase, and their receptors in human and rat sphenopalatine ganglion

    DEFF Research Database (Denmark)

    Csati, A; Tajti, J; Kuris, A

    2012-01-01

    Cranial parasympathetic outflow is mediated through the sphenopalatine ganglion (SPG). The present study was performed to examine the expression of the parasympathetic signaling transmitters and their receptors in human and rat SPG. Indirect immunofluorescence technique was used for the demonstra......Cranial parasympathetic outflow is mediated through the sphenopalatine ganglion (SPG). The present study was performed to examine the expression of the parasympathetic signaling transmitters and their receptors in human and rat SPG. Indirect immunofluorescence technique was used...... for the demonstration of vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP), nitric oxide synthase (NOS), glutamine synthetase (GS), glial fibrillary acidic protein (GFAP), VIP and PACAP common receptors (VPAC1, VPAC2), and PACAP receptor (PAC1). In addition, double labeling...

  20. Opioid Receptor Activity and Analgesic Potency of DPDPE Peptide Analogues Containing a Xylene Bridge.

    Science.gov (United States)

    Stefanucci, Azzurra; Novellino, Ettore; Mirzaie, Sako; Macedonio, Giorgia; Pieretti, Stefano; Minosi, Paola; Szűcs, Edina; Erdei, Anna I; Zádor, Ferenc; Benyhe, Sándor; Mollica, Adriano

    2017-04-13

    d-Pen 2 ,d-Pen 5 enkephalin (DPDPE) is one of the most selective synthetic peptide agonists targeting the δ-opioid receptor. Three cyclic analogues of DPDPE containing a xylene bridge in place of disulfide bond have been synthesized and fully characterized as opioid receptors agonists. The in vitro activity was investigated showing a good affinity of 7a - c for μ- and δ-receptors. In vivo biological assays revealed that 7b is the most potent analogue with the ability to maintain high level of analgesia from 15 to 60 min following intracerebroventricular (i.c.v.) administration, whereas DPDPE was slightly active until 45 min. Compound 7b induced long lasting analgesia also after subcutaneous administration, whereas DPDPE was inactive.

  1. A Novel Non-Peptidic Agonist of the Ghrelin Receptor with Orexigenic Activity In vivo

    Science.gov (United States)

    Pastor-Cavada, Elena; Pardo, Leticia M.; Kandil, Dalia; Torres-Fuentes, Cristina; Clarke, Sarah L.; Shaban, Hamdy; McGlacken, Gerard P.; Schellekens, Harriet

    2016-11-01

    Loss of appetite in the medically ill and ageing populations is a major health problem and a significant symptom in cachexia syndromes, which is the loss of muscle and fat mass. Ghrelin is a gut-derived hormone which can stimulate appetite. Herein we describe a novel, simple, non-peptidic, 2-pyridone which acts as a selective agonist for the ghrelin receptor (GHS-R1a). The small 2-pyridone demonstrated clear agonistic activity in both transfected human cells and mouse hypothalamic cells with endogenous GHS-R1a receptor expression. In vivo tests with the hit compound showed significant increased food intake following peripheral administration, which highlights the potent orexigenic effect of this novel GHS-R1a receptor ligand.

  2. Human formyl peptide receptor ligand binding domain(s). Studies using an improved mutagenesis/expression vector reveal a novel mechanism for the regulation of receptor occupancy.

    Science.gov (United States)

    Perez, H D; Vilander, L; Andrews, W H; Holmes, R

    1994-09-09

    Recently, we reported the domain requirements for the binding of formyl peptide to its specific receptor. Based on experiments using receptor chimeras, we also postulated an importance for the amino-terminal domain of the receptor in ligand binding (Perez, H. D., Holmes, R., Vilander, L., Adams, R., Manzana, W., Jolley, D., and Andrews, W. H. (1993) J. Biol. Chem. 268, 2292-2295). We have begun to perform a detailed analysis of the regions within the formyl peptide receptor involved in ligand binding. To address the importance of the receptor amino-terminal domain, we substituted (or inserted) hydrophilic sequences within the amino-terminal domain, expressed the receptors, and determined their ability to bind ligand. A stretch of nine amino acids next to the initial methionine was identified as crucial for receptor occupancy. A peptide containing such a sequence specifically completed binding of the ligand to the receptor. Alanine screen mutagenesis of the second extracellular domain also identified amino acids involved in ligand binding as well as a disulfide bond (Cys98 to Cys176) crucial for maintaining the binding pocket. These studies provide evidence for a novel mechanism involved in regulation of receptor occupancy. Binding of the ligand induces conformational changes in the receptor that result in the apposition of the amino-terminal domain over the ligand, providing a lid to the binding pocket.

  3. Denatonium induces secretion of glucagon-like peptide-1 through activation of bitter taste receptor pathways

    Science.gov (United States)

    Kim, Ki-Suk; Egan, Josephine M.

    2016-01-01

    Aims/hypothesis This study was designed to ascertain whether human enteroendocrine cells express bitter taste receptors, and whether activation of these receptors with bitter-tasting ligands induces secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY). Methods We used human enteroendocrine NCI-H716 cells, isolated duodenal segments from mice, and whole mice as our experimental systems for investigating stimuli and mechanisms underlying GLP-1- and PYY-stimulated release. We measured hormone levels by ELISA and determined bitter taste receptor expression by real-time quantitative PCR. We adopted a pharmacological approach using inhibitors and enhancers of downstream signalling pathways known to be involved in bitter taste transduction in taste bud cells to investigate these pathways in NCI-H716 cells. Results Using a pharmacological approach, we identified signalling pathways triggered by the denatonium benzoate (DB)-activated bitter receptors. This involved activation of α-gustducin (Gαgust)—the specific G-protein subunit that is also present in taste bud cells—reduction of intracellular cAMP levels and enhancement of phospholipase C (PLC) activity, which ultimately led to increased intracellular calcium concentrations and hormone release. Gavage of DB, followed by gavage of glucose, to db/db mice stimulated GLP-1 and subsequent insulin secretion, leading to lower blood glucose levels. Conclusions/interpretation Our study demonstrates that activation of gut-expressed bitter taste receptors stimulates GLP-1 secretion in a PLC-dependent manner. In diabetic mice, DB (a ligand of bitter taste receptor cells), when given via gavage, lowers blood glucose levels in diabetic mice after oral glucose administration, through increased secretion of GLP-1. PMID:25016595

  4. The plant natriuretic peptide receptor is a guanylyl cyclase and enables cGMP-dependent signaling

    KAUST Repository

    Turek, Ilona

    2016-03-05

    The functional homologues of vertebrate natriuretic peptides (NPs), the plant natriuretic peptides (PNPs), are a novel class of peptidic hormones that signal via guanosine 3′,5′-cyclic monophosphate (cGMP) and systemically affect plant salt and water balance and responses to biotrophic plant pathogens. Although there is increasing understanding of the complex roles of PNPs in plant responses at the systems level, little is known about the underlying signaling mechanisms. Here we report isolation and identification of a novel Leucine-Rich Repeat (LRR) protein that directly interacts with A. thaliana PNP, AtPNP-A. In vitro binding studies revealed that the Arabidopsis AtPNP-A binds specifically to the LRR protein, termed AtPNP-R1, and the active region of AtPNP-A is sufficient for the interaction to occur. Importantly, the cytosolic part of the AtPNP-R1, much like in some vertebrate NP receptors, harbors a catalytic center diagnostic for guanylyl cyclases and the recombinant AtPNP-R1 is capable of catalyzing the conversion of guanosine triphosphate to cGMP. In addition, we show that AtPNP-A causes rapid increases of cGMP levels in wild type (WT) leaf tissue while this response is significantly reduced in the atpnp-r1 mutants. AtPNP-A also causes cGMP-dependent net water uptake into WT protoplasts, and hence volume increases, whereas responses of the protoplasts from the receptor mutant are impaired. Taken together, our results suggest that the identified LRR protein is an AtPNP-A receptor essential for the PNP-dependent regulation of ion and water homeostasis in plants and that PNP- and vertebrate NP-receptors and their signaling mechanisms share surprising similarities. © 2016 Springer Science+Business Media Dordrecht

  5. Urotensin II and urotensin II-related peptide activate somatostatin receptor subtypes 2 and 5.

    Science.gov (United States)

    Malagon, Maria M; Molina, Marcelo; Gahete, Manuel D; Duran-Prado, Mario; Martinez-Fuentes, Antonio J; Alcain, Francisco J; Tonon, Marie-Christine; Leprince, Jérôme; Vaudry, Hubert; Castaño, Justo P; Vazquez-Martinez, Rafael

    2008-05-01

    The UII and urotensin II-related peptide (URP) genes belong to the same superfamily as the somatostatin gene. It has been previously shown that somatostatin activates the UII-receptor (UTR). In contrast, the possible interaction between UII and URP and somatostatin receptors has remained scarcely analyzed. Herein, we have investigated the effects of UII and URP on cell proliferation and free cytosolic Ca2+ concentration ([Ca2+]i) in CHO-K1 cells stably expressing the porcine somatostatin receptor subtypes sst2 and sst5. Results show that both UII and URP induce stimulation of cell proliferation mediated by sst2 receptors and UII provokes inhibition of cell proliferation mediated by sst5 receptors. UII and URP also provoked an increase of [Ca2+]i in both sst2- and sst5-transfected cells. Together, our present data demonstrate that UII and URP directly activate sst2 and sst5 and thus mimic the effect of somatostatin on its cognate receptors.

  6. Gastrin-Releasing Peptide Receptor Mediates Activation of the Epidermal Growth Factor Receptor in Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Sufi Mary Thomas

    2005-04-01

    Full Text Available Gastrin-releasing peptide receptor (GRPR and the epidermal growth factor receptor (EGFR are expressed in several cancers including non-small cell lung carcinoma (NSCLC. Here we demonstrate the activation of EGFR by the GRPR ligand, gastrin-releasing peptide (GRP, in NSCLC cells. GRP induced rapid activation of p44/42 MAPK in lung cancer cells through EGFR. GRP-mediated activation of MAPK in NSCLC cells was abrogated by pretreatment with the anti-EGFR-neutralizing antibody, C225. Pretreatment of NSCLC cells with neutralizing antibodies to the EGFR ligands, TGF-α or HB-EGF, also decreased GRP-mediated MAPK activation. On matrix metalloproteinase (MMP inhibition, GRP failed to activate MAPK in NSCLC cells. EGF and GRP both stimulated NSCLC proliferation, and inhibition of either EGFR or GRPR resulted in cell death. Combining a GRPR antagonist with the EGFR tyrosine kinase inhibitor, gefitinib, resulted in additive cytotoxic effects. Additive effects were seen at gefitinib concentrations from 1 to 18μM, encompassing the ID50 values of both gefitinib-sensitive and gefitinib-resistant NSCLC cell lines. Because a major effect of GRPR appears to be promoting the release of EGFR ligand, this study suggests that a greater inhibition of cell proliferation may occur by abrogating EGFR ligand release in consort with inhibition of EGFR.

  7. GluVII:06--a highly conserved and selective anchor point for non-peptide ligands in chemokine receptors

    DEFF Research Database (Denmark)

    Rosenkilde, Mette M; Schwartz, Thue W

    2006-01-01

    to be crucially important for the binding and action of a number of non-peptide ligands in for example the CCR1, CCR2 and CCR5 receptors. It is proposed that in chemokine receptors in general GluVII:06 serves as a selective anchor point for the centrally located, positively charged nitrogen of the small molecule...

  8. Peptides derived from CXCL8 based on in silico analysis inhibit CXCL8 interactions with its receptor CXCR1

    Science.gov (United States)

    Jiang, Shinn-Jong; Liou, Je-Wen; Chang, Chun-Chun; Chung, Yi; Lin, Lee-Fong; Hsu, Hao-Jen

    2015-12-01

    Chemokine CXCL8 is crucial for regulation of inflammatory and immune responses via activating its cognate receptor CXCR1. In this study, molecular docking and binding free energy calculations were combined to predict the initial binding event of CXCL8 to CXCR1 for peptide drug design. The simulations reveal that in the initial binding, the N-loop of CXCL8 interacts with the N-terminus of CXCR1, which is dominated by electrostatic interactions. The derived peptides from the binding region of CXCL8 are synthesized for further confirmation. Surface plasmon resonance analyses indicate that the CXCL8 derived peptide with 14 residues is able to bind to the receptor CXCR1 derived peptide with equilibrium KD of 252 μM while the peptide encompassing a CXCL8 K15A mutation hardly binds to CXCR1 derived peptide (KD = 1553 μM). The cell experiments show that the designed peptide inhibits CXCL8-induced and LPS-activated monocytes adhesion and transmigration. However, when the peptides were mutated on two lysine residues (K15 and K20), the inhibition effects were greatly reduced indicating these two amino acids are key residues for the initial binding of CXCL8 to CXCR1. This study demonstrates that in silico prediction based functional peptide design can be effective for developing anti-inflammation drugs.

  9. The structure and function of the glucagon-like peptide-1 receptor and its ligands.

    Science.gov (United States)

    Donnelly, Dan

    2012-05-01

    Glucagon-like peptide-1(7-36)amide (GLP-1) is a 30-residue peptide hormone released from intestinal L cells following nutrient consumption. It potentiates the glucose-induced secretion of insulin from pancreatic beta cells, increases insulin expression, inhibits beta-cell apoptosis, promotes beta-cell neogenesis, reduces glucagon secretion, delays gastric emptying, promotes satiety and increases peripheral glucose disposal. These multiple effects have generated a great deal of interest in the discovery of long-lasting agonists of the GLP-1 receptor (GLP-1R) in order to treat type 2 diabetes. This review article summarizes the literature regarding the discovery of GLP-1 and its physiological functions. The structure, function and sequence-activity relationships of the hormone and its natural analogue exendin-4 (Ex4) are reviewed in detail. The current knowledge of the structure of GLP-1R, a Family B GPCR, is summarized and discussed, before its known interactions with the principle peptide ligands are described and summarized. Finally, progress in discovering non-peptide ligands of GLP-1R is reviewed. GLP-1 is clearly an important hormone linking nutrient consumption with blood sugar control, and therefore knowledge of its structure, function and mechanism of action is of great importance. © 2011 The Author. British Journal of Pharmacology © 2011 The British Pharmacological Society.

  10. Increased natriuretic peptide receptor A and C gene expression in rats with pressure-overload cardiac hypertrophy

    DEFF Research Database (Denmark)

    Christoffersen, Tue E.H.; Aplin, Mark; Strom, Claes C.

    2006-01-01

    Both atrial (ANP) and brain (BNP) natriuretic peptide affect development of cardiac hypertrophy and fibrosis via binding to natriuretic peptide receptor (NPR)-A in the heart. A putative clearance receptor, NPR-C, is believed to regulate cardiac levels of ANP and BNP. The renin-angiotensin system...... also affects cardiac hypertrophy and fibrosis. In this study we examined the expression of genes for the NPRs in rats with pressure-overload cardiac hypertrophy. The ANG II type 1 receptor was blocked with losartan (10 mg.kg(-1).day(-1)) to investigate a possible role of the renin-angiotensin system...

  11. The melanocortin-4 receptor is expressed in enteroendocrine L cells and regulates the release of peptide YY and glucagon-like peptide 1 in vivo

    DEFF Research Database (Denmark)

    Panaro, Brandon L; Tough, Iain R; Engelstoft, Maja S

    2014-01-01

    The melanocortin-4 receptor (MC4R) is expressed in the brainstem and vagal afferent nerves and regulates a number of aspects of gastrointestinal function. Here we show that the receptor is also diffusely expressed in cells of the gastrointestinal system, from stomach to descending colon....... Furthermore, MC4R is the second most highly enriched GPCR in peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) expressing enteroendocrine L cells. When vectorial ion transport is measured across mouse or human intestinal mucosa, administration of α-MSH induces a MC4R-specific PYY-dependent antisecretory...... response consistent with a role for the MC4R in paracrine inhibition of electrolyte secretion. Finally, MC4R-dependent acute PYY and GLP-1 release from L cells can be stimulated in vivo by intraperitoneal (i.p.) administration of melanocortin peptides to mice. This suggests physiological significance...

  12. Targeting the gastrin-releasing peptide receptor pathway to treat cognitive dysfunction associated with Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Rafael Roesler

    Full Text Available Abstract Increasing evidence indicates that bombesin (BB-like peptides (BLPs, such as the gastrin-releasing peptide (GRP and its receptor (GRPR, might play a role in neurological and psychiatric disorders. The present study reviews findings from animal and human studies suggesting that the GRPR should be considered a target for the treatment of cognitive dysfunction in patients with Alzheimer's disease (AD. Abnormalities in GRPR-triggered signaling have been described in both fibroblasts from patients with AD, and in transgenic mouse models of AD. Pharmacological and genetic preclinical studies have indicated that BLPs and the GRPR are importantly involved in regulating cognitive function. Moreover, drugs acting at the GRPR have been shown to enhance memory and ameliorate cognitive dysfunction in experimental models of amnesia associated with AD. Taken together, these findings support the view that the GRPR is a novel therapeutic target for the treatment of memory deficits associated with AD.

  13. The orphan G protein-coupled receptor GPR139 is activated by the peptides

    DEFF Research Database (Denmark)

    Jensen, Anne Cathrine Nøhr; Shehata, Mohamed A; Hauser, Alexander S

    2017-01-01

    GPR139 is an orphan G protein-coupled receptor that is expressed primarily in the brain. Not much is known regarding the function of GPR139. Recently we have shown that GPR139 is activated by the amino acids l-tryptophan and l-phenylalanine (EC50 values of 220 μM and 320 μM, respectively), as well...... as di-peptides comprised of aromatic amino acids. This led us to hypothesize that GPR139 may be activated by peptides. Sequence alignment of the binding cavities of all class A GPCRs, revealed that the binding pocket of the melanocortin 4 receptor is similar to that of GPR139. Based on the chemogenomics...... principle "similar targets bind similar ligands", we tested three known endogenous melanocortin 4 receptor agonists; adrenocorticotropic hormone (ACTH) and α- and β-melanocyte stimulating hormone (α-MSH and β-MSH) on CHO-k1 cells stably expressing the human GPR139 in a Fluo-4 Ca(2+)-assay. All three...

  14. Toll-like receptor and antimicrobial peptide expression in the bovine endometrium

    Directory of Open Access Journals (Sweden)

    Conlan R Steven

    2008-11-01

    Full Text Available Abstract Background The endometrium is commonly infected with bacteria leading to severe disease of the uterus in cattle and humans. The endometrial epithelium is the first line of defence for this mucosal surface against bacteria and Toll-like receptors (TLRs are a critical component of the innate immune system for detection of pathogen associated molecular patterns (PAMPs. Antimicrobial peptides, acute phase proteins and Mucin-1 (MUC-1 also provide non-specific defences against microbes on mucosal surfaces. The present study examined the expression of innate immune defences in the bovine endometrium and tested the hypothesis that endometrial epithelial cells express functional receptors of the TLR family and the non-specific effector molecules for defence against bacteria. Methods Bovine endometrial tissue and purified populations of primary epithelial and stromal cells were examined using RT-PCR for gene expression of TLRs, antimicrobial peptides and MUC-1. Functional responses were tested by evaluating the secretion of prostaglandin E2 and acute phase proteins when cells were treated with bacterial PAMPs such as bacterial lipopolysaccharide (LPS and lipoproteins. Results The endometrium expressed TLRs 1 to 10, whilst purified populations of epithelial cells expressed TLRs 1 to 7 and 9, and stromal cells expressed TLRs 1 to 4, 6, 7, 9 and 10. The TLRs appear to be functional as epithelial cells secreted prostaglandin E2 in response to bacterial PAMPs. In addition, the epithelial cells expressed antimicrobial peptides, such as Tracheal and Lingual Antimicrobial Peptides (TAP and LAP and MUC-1, which were upregulated when the cells were treated with LPS. However, the epithelial cells did not express appreciable amounts of the acute phase proteins haptoglobin or serum amyloid A. Conclusion Epithelial cells have an essential role in the orchestration of innate immune defence of the bovine endometrium and are likely to be the key to prevention of

  15. Umami receptor activation increases duodenal bicarbonate secretion via glucagon-like peptide-2 release in rats.

    Science.gov (United States)

    Wang, Joon-Ho; Inoue, Takuya; Higashiyama, Masaaki; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2011-11-01

    Luminal nutrient chemosensing during meal ingestion is mediated by intestinal endocrine cells, which regulate secretion and motility via the release of gut hormones. We have reported that luminal coperfusion of L-Glu and IMP, common condiments providing the umami or proteinaceous taste, synergistically increases duodenal bicarbonate secretion (DBS) possibly via taste receptor heterodimers, taste receptor type 1, member 1 (T1R1)/R3. We hypothesized that glucose-dependent insulinotropic peptide (GIP) or glucagon-like peptide (GLP) is released by duodenal perfusion with L-Glu/IMP. We measured DBS with pH and CO(2) electrodes through a perfused rat duodenal loop in vivo. GIP, exendin (Ex)-4 (GLP-1 receptor agonist), or GLP-2 was intravenously infused (0.01-1 nmol/kg/h). l-Glu (10 mM) and IMP (0.1 mM) were luminally perfused with or without bolus intravenous injection (3 or 30 nmol/kg) of the receptor antagonists Pro(3)GIP, Ex-3(9-39), or GLP-2(3-33). GIP or GLP-2 infusion dose-dependently increased DBS, whereas Ex-4 infusion gradually decreased DBS. Luminal perfusion of l-Glu/IMP increased DBS, with no effect of Pro(3)GIP or Ex-3(9-39), whereas GLP-2(3-33) inhibited L-Glu/IMP-induced DBS. Vasoactive intestinal peptide (VIP)(6-28) intravenously or N(G)-nitro-L-arginine methyl ester coperfusion inhibited the effect of L-Glu/IMP. Perfusion of L-Glu/IMP increased portal venous concentrations of GLP-2, followed by a delayed increase of GLP-1, with no effect on GIP release. GLP-1/2 and T1R1/R3 were expressed in duodenal endocrine-like cells. These results suggest that luminal L-Glu/IMP-induced DBS is mediated via GLP-2 release and receptor activation followed by VIP and nitric oxide release. Because GLP-1 is insulinotropic and GLP-2 is intestinotrophic, umami receptor activation may have additional benefits in glucose metabolism and duodenal mucosal protection and regeneration.

  16. Crystal Structure of Glucagon-like Peptide-1 in Complex with the Extracellular Domain of the Glucagon-like Peptide-1 Receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Garibay, P.; Knudsen, L.B.

    2010-01-01

    GLP-1 (glucagon-like peptide-1) is an incretin released from intestinal L-cells in response to food intake. Activation of the GLP-1 receptor potentiates the synthesis and release of insulin from pancreatic beta-cells in a glucose-dependent manner. The GLP-1 receptor belongs to class B of the G....... The structure shows that important hydrophobic ligand-receptor interactions are conserved in agonist-and antagonist-bound forms of the extracellular domain, but certain residues in the ligand-binding site adopt a GLP-1-specific conformation. GLP-1 is a kinked but continuous alpha-helix from Thr(13) to Val(33...

  17. Exendin-4, a glucagon-like peptide-1 receptor agonist, reduces intimal thickening after vascular injury

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Hiromasa [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Nomiyama, Takashi, E-mail: tnomiyama@fukuoka-u.ac.jp [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Mita, Tomoya; Yasunari, Eisuke; Azuma, Kosuke; Komiya, Koji; Arakawa, Masayuki; Jin, Wen Long; Kanazawa, Akio [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Kawamori, Ryuzo [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Sportology Center, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Center for Beta Cell Biology and Regeneration, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Fujitani, Yoshio; Hirose, Takahisa [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Watada, Hirotaka, E-mail: hwatada@juntendo.ac.jp [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Sportology Center, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan)

    2011-02-04

    Research highlights: {yields} Exendin-4 reduces neointimal formation after vascular injury in a mouse model. {yields} Exendin-4 dose not alter metabolic parameters in non-diabetic, non-obese mouse model. {yields} Exendin-4 reduces PDGF-induced cell proliferation in cultured SMCs. {yields} Exendin-4 may reduces neointimal formation after vascular injury at least in part through its direct action on SMCs. -- Abstract: Glucagon-like peptide-1 is a hormone secreted by L cells of the small intestine and stimulates glucose-dependent insulin response. Glucagon-like peptide-1 receptor agonists such as exendin-4 are currently used in type 2 diabetes, and considered to have beneficial effects on the cardiovascular system. To further elucidate the effect of glucagon-like peptide-1 receptor agonists on cardiovascular diseases, we investigated the effects of exendin-4 on intimal thickening after endothelial injury. Under continuous infusion of exendin-4 at 24 nmol/kg/day, C57BL/6 mice were subjected to endothelial denudation injury of the femoral artery. Treatment of mice with exendin-4 reduced neointimal formation at 4 weeks after arterial injury without altering body weight or various metabolic parameters. In addition, in vitro studies of isolated murine, rat and human aortic vascular smooth muscle cells showed the expression of GLP-1 receptor. The addition of 10 nM exendin-4 to cultured smooth muscle cells significantly reduced their proliferation induced by platelet-derived growth factor. Our results suggested that exendin-4 reduced intimal thickening after vascular injury at least in part by the suppression of platelet-derived growth factor-induced smooth muscle cells proliferation.

  18. The dynamics of interleukin-8 and its interaction with human CXC receptor I peptide

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick, Agnieszka; Holliday, Michael; Isern, Nancy G.; Zhang, Fengli; Camilloni, Carlo; Huynh, Chi; Vendruscolo, Michele; Armstrong, Geoffrey S.; Eisenmesser, Elan Z.

    2014-01-20

    Interleukin-8 (CXCL8, IL-8) is a pro-inflammatory chemokine important for the regulation of inflammatory and immune responses via its interaction with G-protein coupled receptors, including CXC receptor 1 (CXCR1). CXCL8 exists as both a monomer and as a dimer at physiological concentrations, yet the molecular basis of CXCL8 interaction with its receptor as well as the importance of CXCL8 dimer formation remain poorly characterized. Although several biological studies have indicated that both the CXCL8 monomer and dimer are active, biophysical studies have reported conflicting results regarding the binding of CXCL8 to CXCR1. To clarify this problem, we expressed and purified a peptide (hCXCR1pep) corresponding to the N-terminal region of human CXCR1 (hCXCR1) and utilized nuclear magnetic resonance (NMR) spectroscopy to interrogate the binding of wild-type CXCL8 and a previously reported mutant (CXCL8M) that stabilizes the monomeric form. Our data reveal that CXCL8M engages hCXCR1pep with a slightly higher affinity than CXCL8, and that CXCL8 does not dissociate upon binding hCXCR1pep. These investigations also indicate that CXCL8 exhibits inherent flexibility within its receptor-binding site on multiple timescales, which may help explain the versatility in this interleukin for engaging its target receptors.

  19. Characterization of atrial natriuretic peptide receptors in brain microvessel endothelial cells

    Science.gov (United States)

    Whitson, P. A.; Huls, M. H.; Sams, C. F.

    1991-01-01

    Atrial natriuretic peptide (ANP) binding and ANP-induced increases in cyclic guanosine monophosphate (cGMP) levels have been observed in brain microvessels (Chabrier et al., 1987; Steardo and Nathanson, 1987), suggesting that this fluid-regulating hormone may play a role in the fluid homeostasis of the brain. This study was initiated to characterize the ANP receptors in primary cultures of brain microvessel endothelial cells (BMECs). The apparent equilibrium dissociation constant, Kd, for ANP increased from 0.25 nM to 2.5 nM, and the number of ANP binding sites as determined by Scatchard analysis increased from 7,100 to 170,000 sites/cell between 2 and 10 days of culture following monolayer formation. Time- and concentration-dependent studies on the stimulation of cGMP levels by ANP indicated that guanylate cyclase-linked ANP receptors were present in BMECs. The relative abilities of ANP, brain natriuretic peptide (BNP), and a truncated analog of ANP containing amino acids 5-27 (ANP 5-27) to modulate the accumulation of cGMP was found to be ANP greater than BNP much greater than ANP 5-27. Affinity cross-linking with disuccinimidyl suberate and radiolabeled ANP followed by gel electrophoresis under reducing conditions demonstrated a single band corresponding to the 60-70 kD receptor, indicating the presence of the nonguanylate cyclase-linked ANP receptor. Radiolabeled ANP binding was examined in the presence of various concentrations of either ANP, BNP, or ANP 5-27 and suggested that a large proportion of the ANP receptors present in blood-brain barrier endothelial cells bind all of these ligands similarly. These data indicate both guanylate cyclase linked and nonguanylate cyclase linked receptors are present on BMECs and that a higher proportion of the nonguanylate cyclase linked receptors is expressed. This in vitro culture system may provide a valuable tool for the examination of ANP receptor expression and function in blood-brain barrier endothelial cells.

  20. Urinary responses to acute moxonidine are inhibited by natriuretic peptide receptor antagonist

    OpenAIRE

    El-Ayoubi, Rouwayda; Menaouar, Ahmed; Gutkowska, Jolanta; Mukaddam-Daher, Suhayla

    2005-01-01

    We have previously shown that acute intravenous injections of moxonidine and clonidine increase plasma atrial natriuretic peptide (ANP), a vasodilator, diuretic and natriuretic hormone. We hypothesized that moxonidine stimulates the release of ANP, which would act on its renal receptors to cause diuresis and natriuresis, and these effects may be altered in hypertension.Moxonidine (0, 10, 50, 100 or 150 μg in 300 μl saline) and clonidine (0, 1, 5 or 10 μg in 300 μl saline) injected intravenous...

  1. Increased expression of glucagon-like peptide-1 receptors in psoriasis plaques

    DEFF Research Database (Denmark)

    Faurschou, Annesofie; Pedersen, Jens; Gyldenløve, Mette

    2013-01-01

    Recent case reports suggest that treatment with glucagon-like peptide-1 (GLP-1) agonists results in clinical improvement of psoriasis. The purpose of this study was to determine whether GLP-1 receptors (GLP-1Rs) are found in the skin of healthy volunteers and psoriasis patients and if so, whether...... in either stimulated or unstimulated cultured human keratinocytes. Our results show increased presence of GLP-1Rs in psoriasis plaques and that this most likely is due to infiltration with immune cells. This offers a possible explanation for the positive effect of treatment with GLP-1R agonists in patients...

  2. Glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes

    Science.gov (United States)

    Lee, Seungah

    2017-01-01

    The prevalence of type 2 diabetes (T2D) is increasing worldwide. Patients with T2D suffer from various diabetes-related complications. Since there are many patients with T2D that cannot be controlled by previously developed drugs, it has been necessary to develop new drugs, one of which is a glucagon-like peptide-1 (GLP-1) based therapy. GLP-1 has been shown to ameliorate diabetes-related conditions by augmenting pancreatic β-cell insulin secretion and having the low risk of causing hypoglycemia. Because of a very short half-life of GLP-1, many researches have been focused on the development of GLP-1 receptor (GLP-1R) agonists with long half-lives such as exenatide and dulaglutide. Now GLP-1R agonists have a variety of dosing-cycle forms to meet the needs of various patients. In this article, we review the physiological features of GLP-1, the effects of GLP-1 on T2D, the features of several GLP-1R agonists, and the therapeutic effect on T2D. PMID:28443255

  3. Differential mechanisms of activation of the Ang peptide receptors AT1, AT2, and MAS: using in silico techniques to differentiate the three receptors.

    Directory of Open Access Journals (Sweden)

    Jeremy W Prokop

    Full Text Available The renin-angiotensin system is involved in multiple conditions ranging from cardiovascular disorders to cancer. Components of the pathway, including ACE, renin and angiotensin receptors are targets for disease treatment. This study addresses three receptors of the pathway: AT1, AT2, and MAS and how the receptors are similar and differ in activation by angiotensin peptides. Combining biochemical and amino acid variation data with multiple species sequence alignments, structural models, and docking site predictions allows for visualization of how angiotensin peptides may bind and activate the receptors; allowing identification of conserved and variant mechanisms in the receptors. MAS differs from AT1 favoring Ang-(1-7 and not Ang II binding, while AT2 recently has been suggested to preferentially bind Ang III. A new model of Ang peptide binding to AT1 and AT2 is proposed that correlates data from site directed mutagenesis and photolabled experiments that were previously considered conflicting. Ang II binds AT1 and AT2 through a conserved initial binding mode involving amino acids 111 (consensus 325 of AT1 (Asn interacting with Tyr (4 of Ang II and 199 and 256 (consensus 512 and 621, a Lys and His respectively interacting with Phe (8 of Ang II. In MAS these sites are not conserved, leading to differential binding and activation by Ang-(1-7. In both AT1 and AT2, the Ang II peptide may internalize through Phe (8 of Ang II propagating through the receptors' conserved aromatic amino acids to the final photolabled positioning relative to either AT1 (amino acid 294, Asn, consensus 725 or AT2 (138, Leu, consensus 336. Understanding receptor activation provides valuable information for drug design and identification of other receptors that can potentially bind Ang peptides.

  4. Theranostic Prospects of Gastrin-Releasing Peptide Receptor-Radioantagonists in Oncology.

    Science.gov (United States)

    Maina, Theodosia; Nock, Berthold A; Kulkarni, Harshad; Singh, Aviral; Baum, Richard P

    2017-07-01

    Gastrin-releasing peptide receptors (GRPRs) represent attractive targets for cancer diagnosis and therapy owing to their overexpression in widespread human tumors. Bombesin (BBN) analogues coupled to suitable chelators for stable radiometal binding have been proposed for diagnostic imaging and radionuclide therapy (theranostics) of GRPR-positive tumors. Recently, interest has shifted from BBN-like receptor agonists to GRPR-radioantagonists, because radioantagonists do not induce adverse effects after injection to patients and display superior pharmacokinetic in vivo profiles. Thus, they seem more advantageous for clinical use compared to agonists. Newer developments highlighting the theranostic potential of GRPR-radioantagonists in cancer patient management are presented herein. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Treatment of type 2 diabetes with glucagon-like peptide-1 receptor agonists

    DEFF Research Database (Denmark)

    Hansen, K B; Knop, F K; Holst, Jens Juul

    2009-01-01

    The incretin system is an area of great interest for the development of new therapies for the management of type 2 diabetes. Existing antidiabetic drugs are often insufficient at getting patients to glycaemic goals. Furthermore, current treatment modalities are not able to prevent the continued...... ongoing decline in pancreatic beta-cell function and, lastly, they have a number of side effects including hypoglycaemia and weight gain. Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of pharmacological agents, which improve glucose homeostasis in a multifaceted way. Their effects...... of hypoglycaemia with GLP-1 receptor agonists is low, the compounds have clinically relevant effects on body weight, and data are suggesting beneficial effects on cardiovascular risk factors. Exenatide was released in 2005 for the treatment of type 2 diabetes and liraglutide is expected to be approved by the Food...

  6. Concomitant expression of several peptide receptors in neuroendocrine tumours: molecular basis for in vivo multireceptor tumour targeting.

    Science.gov (United States)

    Reubi, Jean Claude; Waser, Beatrice

    2003-05-01

    Peptide receptors have been found to represent excellent targets for in vivo cancer diagnosis and therapy. Recent in vitro studies have shown that many cancers can overexpress not only one but several peptide receptors concomitantly. One of the challenges for nuclear medicine in this field in the coming decade will be to take advantage of the co-expression of peptide receptors for multireceptor tumour targeting. In vitro receptor studies can reveal which peptide receptor is overexpressed in which tumour and which receptors are co-expressed in an individual tumour; such knowledge is a prerequisite for successful in vivo development. One group of tumours of particular interest in this respect is the neuroendocrine tumours, which have previously been shown often to express peptide receptors. This review summarises our investigations of the concomitant expression of 13 different peptide receptors, in more than 100 neuroendocrine tumours of the human intestine, pancreas and lung, using in vitro receptor autoradiography with subtype-selective ligands. The incidence and density of the somatostatin receptors sst(1)-sst(5), the VIP receptors VPAC(1) and VPAC(2), the CCK(1) and CCK(2) receptors, the three bombesin receptor subtypes BB(1) (NMB receptor), BB(2) (GRP receptor) and BB(3), and GLP-1 receptors were evaluated. While the presence of VPAC(1) and sst(2) was detected in the majority of these neuroendocrine tumours, the other receptors, more differentially expressed, revealed a characteristic receptor pattern in several tumour types. Ileal carcinoids expressed sst(2) and VPAC(1) receptors in virtually all cases and had CCK(1), CCK(2), sst(1) or sst(5) in approximately half of the cases; they were the only tumours of this series to express NMB receptors. Insulinomas were characterised by a very high incidence of GLP-1, CCK(2) and VPAC(1) receptors, with the GLP-1 receptors expressed in a particularly high density; they expressed sst(2) in two-thirds and sst(1) in

  7. Concomitant expression of several peptide receptors in neuroendocrine tumours: molecular basis for in vivo multireceptor tumour targeting

    Energy Technology Data Exchange (ETDEWEB)

    Reubi, Jean Claude; Waser, Beatrice [Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Murtenstrasse 31, PO Box 62, 3010, Berne (Switzerland)

    2003-05-01

    Peptide receptors have been found to represent excellent targets for in vivo cancer diagnosis and therapy. Recent in vitro studies have shown that many cancers can overexpress not only one but several peptide receptors concomitantly. One of the challenges for nuclear medicine in this field in the coming decade will be to take advantage of the co-expression of peptide receptors for multireceptor tumour targeting. In vitro receptor studies can reveal which peptide receptor is overexpressed in which tumour and which receptors are co-expressed in an individual tumour; such knowledge is a prerequisite for successful in vivo development. One group of tumours of particular interest in this respect is the neuroendocrine tumours, which have previously been shown often to express peptide receptors. This review summarises our investigations of the concomitant expression of 13 different peptide receptors, in more than 100 neuroendocrine tumours of the human intestine, pancreas and lung, using in vitro receptor autoradiography with subtype-selective ligands. The incidence and density of the somatostatin receptors sst{sub 1}-sst{sub 5}, the VIP receptors VPAC{sub 1} and VPAC{sub 2}, the CCK{sub 1} and CCK{sub 2} receptors, the three bombesin receptor subtypes BB{sub 1} (NMB receptor), BB{sub 2} (GRP receptor) and BB{sub 3}, and GLP-1 receptors were evaluated. While the presence of VPAC{sub 1} and sst{sub 2} was detected in the majority of these neuroendocrine tumours, the other receptors, more differentially expressed, revealed a characteristic receptor pattern in several tumour types. Ileal carcinoids expressed sst{sub 2} and VPAC{sub 1} receptors in virtually all cases and had CCK{sub 1}, CCK{sub 2}, sst{sub 1} or sst{sub 5} in approximately half of the cases; they were the only tumours of this series to express NMB receptors. Insulinomas were characterised by a very high incidence of GLP-1, CCK{sub 2} and VPAC{sub 1} receptors, with the GLP-1 receptors expressed in a

  8. Phthalocyanine-Peptide Conjugates for Epidermal Growth Factor Receptor Targeting1

    Science.gov (United States)

    Ongarora, Benson G.; Fontenot, Krystal R.; Hu, Xiaoke; Sehgal, Inder; Satyanarayana-Jois, Seetharama D.; Vicente, M. Graça H.

    2012-01-01

    Four phthalocyanine (Pc)-peptide conjugates designed to target the epidermal growth factor receptor (EGFR) were synthesized and evaluated in vitro using four cell lines: human carcinoma A431 and HEp2, human colorectal HT-29, and kidney Vero (negative control) cells. Two peptide ligands for EGFR were investigated: EGFR-L1 and -L2, bearing 6 and 13 amino acid residues, respectively. The peptides and Pc-conjugates were shown to bind to EGFR using both theoretical (Autodock) and experimental (SPR) investigations. The Pc-EGFR-L1 conjugates 5a and 5b efficiently targeted EGFR and were internalized, in part due to their cationic charge, whereas the uncharged Pc-EGFR-L2 conjugates 4b and 6a poorly targeted EGFR maybe due to their low aqueous solubility. All conjugates were non-toxic (IC50 > 100 µM) to HT-29 cells, both in the dark and upon light activation (1 J/cm2). Intravenous (iv) administration of conjugate 5b into nude mice bearing A431 and HT-29 human tumor xenografts resulted in a near-IR fluorescence signal at ca. 700 nm, 24 h after administration. Our studies show that Pc-EGFR-L1 conjugates are promising near-IR fluorescent contrast agents for CRC, and potentially other EGFR over-expressing cancers. PMID:22468711

  9. Identification of the bioactive and consensus peptide motif from Momordica charantia insulin receptor-binding protein.

    Science.gov (United States)

    Lo, Hsin-Yi; Li, Chia-Cheng; Ho, Tin-Yun; Hsiang, Chien-Yun

    2016-08-01

    Many food bioactive peptides with diverse functions have been discovered by studying plant proteins. We have previously identified a 68-residue insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia that exhibits hypoglycemic effects in mice via interaction with IR. By in vitro digestion, we found that mcIRBP-19, spanning residues 50-68 of mcIRBP, enhanced the binding of insulin to IR, stimulated the phosphorylation of PDK1 and Akt, induced the expression of glucose transporter 4, and stimulated both the uptake of glucose in cells and the clearance of glucose in diabetic mice. Furthermore, mcIRBP-19 homologs were present in various plants and shared similar β-hairpin structures and IR kinase-activating abilities to mcIRBP-19. In conclusion, our findings suggested that mcIRBP-19 is a blood glucose-lowering bioactive peptide that exhibits IR-binding potentials. Moreover, we newly identified novel IR-binding bioactive peptides in various plants which belonged to different taxonomic families. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Insulin receptor signaling and glucagon-like peptide 1 effects on pancreatic beta cells.

    Science.gov (United States)

    Caporarello, Nunzia; Parrino, Cristina; Trischitta, Vincenzo; Frittitta, Lucia

    2017-01-01

    Glucagon-like peptide-1 (GLP-1) is a potent gluco-incretin hormone, which plays a central role on pancreatic beta cell proliferation, survival and insulin secreting activity and whose analogs are used for treating hyperglycemia in type 2 diabetes mellitus. Notably, abnormal insulin signaling affects all the above-mentioned aspects on pancreatic beta cells. The aim of our study was to investigate whether the protective effects of GLP1-1 on beta cells are affected by altered insulin receptor signaling. To this end, several effects of GLP-1 were studied in INS-1E rat beta cells transfected either with an inhibitor of insulin receptor function (i.e., the Ectonucleotide Pyrophosphatase Phosphodiesterase 1, ENPP1), or with insulin receptor small interfering RNA, as well as in control cells. Crucial experiments were carried out also in a second cell line, namely the βTC-1 mouse beta cells. Our data indicate that in insulin secreting beta cells in which either ENPP1 was up-regulated or insulin receptor was down-regulated, GLP-1 positive effects on several pancreatic beta cell activities, including glucose-induced insulin secretion, cell proliferation and cell survival, were strongly reduced. Further studies are needed to understand whether such a scenario occurs also in humans and, if so, if it plays a role of clinical relevance in diabetic patients with poor responsiveness to GLP-1 related treatments.

  11. Cardiovascular effects of glucagon-like peptide 1 (GLP-1) receptor agonists.

    Science.gov (United States)

    Saraiva, Francisco Kerr; Sposito, Andrei C

    2014-10-22

    Patients with type 2 diabetes have a several-fold increased risk of developing cardiovascular disease when compared with nondiabetic controls. Myocardial infarction and stroke are responsible for 75% of all death in patients with diabetes, who present a 2-4× increased incidence of death from coronary artery disease. Patients with diabetes are considered for cardiovascular disease secondary prevention because their risk level is similar to that reported in patients without diabetes who have already suffered a myocardial infarction. More recently, with a better risk factors control, mainly in intensive LDL cholesterol targets with statins, a significant decrease in acute cardiovascular events was observed in population with diabetes. Together with other major risk factors, type 2 diabetes must be considered as an important cause of cardiovascular disease.Glucagon like peptide-1 receptor agonists represent a novel class of anti-hyperglycemic agents that have a cardiac-friendly profile, preserve neuronal cells and inhibit neuronal degeneration, an anti-inflammatory effect in liver protecting it against steatosis, increase insulin sensitivity, promote weight loss, and increase satiety or anorexia.This review is intended to rationally compile the multifactorial cardiovascular effects of glucagon-like peptide-1 receptor agonists available for the treatment of patients with type 2 diabetes.

  12. Differential binding of urokinase and peptide antagonists to the urokinase receptor

    DEFF Research Database (Denmark)

    Engelholm, L H; Behrendt, N

    2001-01-01

    for the invasion of cancer cells, thus making uPAR a potential target for anti-invasive therapy based on binding antagonists. A remarkable property of the uPA-uPAR system is a pronounced species specificity in ligand recognition. We have now cloned and studied uPAR from four primate species and show that even...... though these sequences contain very few substitutions relative to the human uPAR, the receptor protein products differ markedly in terms of ligand selectivity. Thus, a well described competitive peptide antagonist directed against the human uPAR reacts with only one of the monkey receptors (chimpanzee u......PAR), in spite of the fact that uPAR from all of the four species cross-reacts with human uPA. Notably, uPAR from African green monkey, which is completely devoid of reactivity with the peptide, contains only three substitutions relative to chimpanzee uPAR in the molecular regions critical for binding...

  13. Formyl peptide receptor as a novel therapeutic target for anxiety-related disorders.

    Directory of Open Access Journals (Sweden)

    Irene Gallo

    Full Text Available Formyl peptide receptors (FPR belong to a family of sensors of the immune system that detect microbe-associated molecules and inform various cellular and sensorial mechanisms to the presence of pathogens in the host. Here we demonstrate that Fpr2/3-deficient mice show a distinct profile of behaviour characterised by reduced anxiety in the marble burying and light-dark box paradigms, increased exploratory behaviour in an open-field, together with superior performance on a novel object recognition test. Pharmacological blockade with a formyl peptide receptor antagonist, Boc2, in wild type mice reproduced most of the behavioural changes observed in the Fpr2/3(-/- mice, including a significant improvement in novel object discrimination and reduced anxiety in a light/dark shuttle test. These effects were associated with reduced FPR signalling in the gut as shown by the significant reduction in the levels of p-p38. Collectively, these findings suggest that homeostatic FPR signalling exerts a modulatory effect on anxiety-like behaviours. These findings thus suggest that therapies targeting FPRs may be a novel approach to ameliorate behavioural abnormalities present in neuropsychiatric disorders at the cognitive-emotional interface.

  14. Characterization of the neuropeptide Y system in the frog Silurana tropicalis (Pipidae): three peptides and six receptor subtypes.

    Science.gov (United States)

    Sundström, G; Xu, B; Larsson, T A; Heldin, J; Bergqvist, C A; Fredriksson, R; Conlon, J M; Lundell, I; Denver, R J; Larhammar, D

    2012-07-01

    Neuropeptide Y and its related peptides PYY and PP (pancreatic polypeptide) are involved in feeding behavior, regulation of the pituitary and the gastrointestinal tract, and numerous other functions. The peptides act on a family of G-protein coupled receptors with 4-7 members in jawed vertebrates. We describe here the NPY system of the Western clawed frog Silurana (Xenopus) tropicalis. Three peptides, NPY, PYY and PP, were identified together with six receptors, namely subtypes Y1, Y2, Y4, Y5, Y7 and Y8. Thus, this frog has all but one of the ancestral seven gnathostome NPY-family receptors, in contrast to mammals which have lost 2-3 of the receptors. Expression levels of mRNA for the peptide and receptor genes were analyzed in a panel of 19 frog tissues using reverse transcriptase quantitative PCR. The peptide mRNAs had broad distribution with highest expression in skin, blood and small intestine. NPY mRNA was present in the three brain regions investigated, but PYY and PP mRNAs were not detectable in any of these. All receptor mRNAs had similar expression profiles with high expression in skin, blood, muscle and heart. Three of the receptors, Y5, Y7 and Y8, could be functionally expressed in HEK-293 cells and characterized with binding studies using the three frog peptides. PYY had the highest affinity for all three receptors (K(i) 0.042-0.34 nM). Also NPY and PP bound to the Y8 receptor with high affinity (0.14 and 0.50 nM). The low affinity of NPY for the Y5 receptor (100-fold lower than PYY) differs from mammals and chicken. This may suggest a less important role of NPY on Y5 in appetite stimulation in the frog compared with amniotes. In conclusion, our characterization of the NPY system in S. tropicalis with its six receptors demonstrates not only greater complexity than in mammals but also some interesting differences in ligand-receptor preferences. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Peptide imprinted receptors for the determination of the small cell lung cancer associated biomarker progastrin releasing peptide

    DEFF Research Database (Denmark)

    Qader, A. A.; Urraca, J.; Torsetnes, S. B.

    2014-01-01

    Peptide imprinted polymers were developed for detection of progastrin releasing peptide (ProGRP); a low abundant blood based biomarker for small cell lung cancer. The polymers targeted the proteotypic nona-peptide sequence NLLGLIEAK and were used for selective enrichment of the proteotypic peptide...... prior to LCMS based quantification. Peptide imprinted polymers with the best affinity characteristics were first identified from a 96-polymer combinatorial library. The effects of functional monomers, crosslinker, porogen, and template on adsorption capacity and selectivity for NLLGLIEAK were...... investigated and optimized. Ultimately, a solid phase extraction method was developed for highly selective enrichment of the target peptide from tryptic digests. (C) 2014 Elsevier B.V. All rights reserved....

  16. A strategy using NMR peptide structures of thromboxane A2 receptor as templates to construct ligand-recognition pocket of prostacyclin receptor

    Directory of Open Access Journals (Sweden)

    Ruan Ke-He

    2005-11-01

    Full Text Available Abstract Background: Prostacyclin receptor (IP and thromboxane A2 receptor (TP belong to rhodopsin-type G protein-coupling receptors and respectively bind to prostacyclin and thromboxane A2 derived from arachidonic acid. Recently, we have determined the extracellular loop (eLP structures of the human TP receptor by 2-D 1H NMR spectroscopy using constrained peptides mimicking the individual eLP segments. The studies have identified the segment along with several residues in the eLP domains important to ligand recognition, as well as proposed a ligand recognition pocket for the TP receptor. Results: The IP receptor shares a similar primary structure in the eLPs with those of the TP receptor. Forty percent residues in the second eLPs of the receptors are identical, which is the major region involved in forming the ligand recognition pocket in the TP receptor. Based on the high homology score, the eLP domains of the IP receptor were constructed by the homology modeling approach using the NMR structures of the TP eLPs as templates, and then configured to the seven transmembrane (TM domains model constructed using the crystal structure of the bovine rhodopsin as a template. A NMR structure of iloprost was docked into the modeled IP ligand recognition pocket. After dynamic studies, the segments and residues involved in the IP ligand recognition were proposed. A key residue, Arg173 involved in the ligand recognition for the IP receptor, as predicted from the modeling, was confirmed by site-directed mutagenesis. Conclusion: A 3-D model of the human IP receptor was constructed by homology modeling using the crystal structure of bovine rhodopsin TM domains and the NMR structures of the synthetic constrained peptides of the eLP domains of the TP receptor as templates. This strategy can be applied to molecular modeling and the prediction of ligand recognition pockets for other prostanoid receptors.

  17. The glucagon-like peptide 1 receptor agonist Exendin-4 decreases relapse-like drinking in socially housed mice

    DEFF Research Database (Denmark)

    Thomsen, Morgane; Dencker, Ditte; Wörtwein, Gitta

    2017-01-01

    Glucagon-like peptide-1 (GLP-1) is a gut peptide that regulates food intake and glucose metabolism. GLP-1 is also produced and released in the brain, and GLP-1 receptors are expressed in brain regions important for alcohol and drug reward, and for the development of addiction. GLP-1 receptor...... alcohol deprivation. Treatment continued for 8 additional days after reintroducing access to alcohol. A high-precision automated fluid consumption system was used to monitor intake of alcohol and water, drinking kinetics, and locomotor activity. Exendin-4 prevented the deprivation-induced increase...

  18. Biased Agonism of Endogenous Opioid Peptides at the μ-Opioid Receptor.

    Science.gov (United States)

    Thompson, Georgina L; Lane, J Robert; Coudrat, Thomas; Sexton, Patrick M; Christopoulos, Arthur; Canals, Meritxell

    2015-08-01

    Biased agonism is having a major impact on modern drug discovery, and describes the ability of distinct G protein-coupled receptor (GPCR) ligands to activate different cell signaling pathways, and to result in different physiologic outcomes. To date, most studies of biased agonism have focused on synthetic molecules targeting various GPCRs; however, many of these receptors have multiple endogenous ligands, suggesting that "natural" bias may be an unappreciated feature of these GPCRs. The μ-opioid receptor (MOP) is activated by numerous endogenous opioid peptides, remains an attractive therapeutic target for the treatment of pain, and exhibits biased agonism in response to synthetic opiates. The aim of this study was to rigorously assess the potential for biased agonism in the actions of endogenous opioids at the MOP in a common cellular background, and compare these to the effects of the agonist d-Ala2-N-MePhe4-Gly-ol enkephalin (DAMGO). We investigated activation of G proteins, inhibition of cAMP production, extracellular signal-regulated kinase 1 and 2 phosphorylation, β-arrestin 1/2 recruitment, and MOP trafficking, and applied a novel analytical method to quantify biased agonism. Although many endogenous opioids displayed signaling profiles similar to that of DAMGO, α-neoendorphin, Met-enkephalin-Arg-Phe, and the putatively endogenous peptide endomorphin-1 displayed particularly distinct bias profiles. These may represent examples of natural bias if it can be shown that they have different signaling properties and physiologic effects in vivo compared with other endogenous opioids. Understanding how endogenous opioids control physiologic processes through biased agonism can reveal vital information required to enable the design of biased opioids with improved pharmacological profiles and treat diseases involving dysfunction of the endogenous opioid system. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  19. Peptide receptor chemoradionuclide therapy in small cell carcinoma: from bench to bedside

    Energy Technology Data Exchange (ETDEWEB)

    Lewin, Jeremy; Rao, Aparna; Mileshkin, Linda [Division of Hematology and Medical Oncology, East Melbourne, VIC (Australia); Cullinane, Carleen [Division of Cancer Research, East Melbourne, VIC (Australia); The University of Melbourne, Sir Peter MacCallum Department of Oncology, Melbourne, VIC (Australia); Akhurst, Tim; Eu, Peter [Centre for Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, VIC (Australia); Waldeck, Kelly [Division of Cancer Research, East Melbourne, VIC (Australia); Watkins, D.N. [Monash University, Monash Institute of Medical Research, Clayton, VIC (Australia); Hicks, Rodney J. [Centre for Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, VIC (Australia); The University of Melbourne, Sir Peter MacCallum Department of Oncology, Melbourne, VIC (Australia)

    2015-01-15

    Small cell cancers (SmCC), whether pulmonary (SCLC) or extrapulmonary, have a poor prognosis unless localised at diagnosis. Given a proportion of these cancers express somatostatin receptor subtype 2 (SSTR2), we aimed to investigate the efficacy of targeted peptide receptor chemoradionuclide therapy (PRCRT). In this preclinical study, we used a SCLC xenograft mouse model with high expression of SSTR2 to investigate the effect of peptide receptor radionuclide therapy (PRRT) with chemotherapy compared to either alone. We subsequently explored the clinical utility in a patient with SmCC with high SSTR expression treated with PRCRT. Robust expression of SSTR2 in NCI-H69 SCLC xenografts was documented by {sup 68}Ga-DOTA-octreotate (GaTate) (tumour to background uptake ratio = 35). The combination of PRRT using {sup 177}Lu-DOTA-octreotate (LuTate) with carboplatin/etoposide (C/E) chemotherapy was more effective than either LuTate or C/E alone for regression of the NCI-H69 model (p value < 0.05). PRCRT was associated with significantly prolonged survival versus PRRT (p value = 0.0001) or chemotherapy alone (p value = 0.0058). In the subsequent case study, a patient with relapsed SmCC with high SSTR2 expression on GaTate PET underwent PRCRT with radiosensitising etoposide with evidence of a complete metabolic response for 4 months. Given the limited treatment options in this setting, PRCRT is a promising therapeutic option for SSTR2-expressing SmCC. (orig.)

  20. Heart specific up-regulation of genes for B-type and C-type natriuretic peptide receptors in diabetic mice

    DEFF Research Database (Denmark)

    Christoffersen, Christina; Bartels, E D; Nielsen, L B

    2006-01-01

    Diabetes may cause cardiomyopathy characterized by cardiac fibrosis. Recent studies of genetically modified mice have elucidated a role of the natriuretic peptides (NP), type-A and type-B (ANP and BNP), and their common receptor [natriuretic peptide receptor (NPR), type-A] in development of cardiac...

  1. Glucagon-like peptide receptor agonists and dipeptidyl peptidase-4 inhibitors in the treatment of diabetes: a review of clinical trials

    DEFF Research Database (Denmark)

    Madsbad, Sten; Krarup, Thure; Deacon, Carolyn F

    2008-01-01

    PURPOSE OF REVIEW: To discuss the virtues and shortcomings of the glucagon-like peptide-1 receptor agonists and the dipeptidyl peptidase-4 inhibitors in the treatment of type 2 diabetes. RECENT FINDINGS: The injectable glucagon-like peptide-1 receptor agonists exenatide significantly improves gly...

  2. Anorectic actions of prolactin-releasing peptide are mediated by corticotropin-releasing hormone receptors.

    Science.gov (United States)

    Lawrence, Catherine B; Liu, Yong-Ling; Stock, Michael J; Luckman, Simon M

    2004-01-01

    Prolactin-releasing peptide (PrRP) reduces food intake and body weight and modifies body temperature when administered centrally in rats, suggesting a role in energy homeostasis. However, the mediators of PrRP's actions are unknown. The present study, therefore, first examined the possible involvement of the anorectic neuropeptides corticotropin-releasing hormone (CRH) and the melanocortins (e.g., alpha-melanocyte-stimulating hormone) in PrRP's effects on food intake and core body temperature and, second, determined if PrRP affects energy expenditure by measuring oxygen consumption (Vo2). Intracerebroventricular injection of PrRP (4 nmol) to 24-h-fasted male Sprague-Dawley rats decreased food intake and modified body temperature. Blockade of central CRH receptors by intracerebroventricular coadministration of the CRH receptor antagonist astressin (20 microg) reversed the PrRP-induced reduction in feeding. However, astressin's effect on PrRP-induced changes in body temperature was complicated because the antagonist itself caused a slight rise in body temperature. In contrast, intracerebroventricular coadministration of the melanocortin receptor-3/4 antagonist SHU-9119 (0.1 nmol) had no effect on any of PrRP's actions. Finally, intracerebroventricular injection of PrRP (4 nmol) caused a significantly greater Vo2 over a 3-h test period compared with vehicle-treated rats. These results show that the anorectic actions of PrRP are mediated by central CRH receptors but not by melanocortin receptors-3/4 and that PrRP can modify Vo2.

  3. A Review on the Association between Glucagon-Like Peptide-1 Receptor Agonists and Thyroid Cancer

    Directory of Open Access Journals (Sweden)

    Wei-Yih Chiu

    2012-01-01

    Full Text Available There is a concern on the risk of thyroid cancer associated with glucagon-like peptide-1 (GLP-1 analogs including liraglutide and exenatide. In this article, we review related experimental studies, clinical trials and observational human studies currently available. In rodents, liraglutide activated the GLP-1 receptors on C-cells, causing an increased incidence of C-cell neoplasia. Animal experiments with monkeys demonstrated no increase in calcitonin release and no C-cell proliferation after long-term liraglutide administration. Longitudinal 2-year data from clinical trials do not support any significant risk for the activation or growth of C-cell cancer in humans in response to liraglutide. However, an analysis of the FDA adverse event reporting system database suggested an increased risk for thyroid cancer associated with exenatide after its marketing. Noticeably, a recent study discovered that GLP-1 receptor could also be expressed in human papillary thyroid carcinomas (PTC, but the impact of GLP-1 analogs on PTC is not known. Therefore, GLP-1 analogs might increase the risk of thyroid C-cell pathology in rodents, but its risk in humans awaits confirmation. Since GLP-1 receptor is also expressed in PTC besides C-cells, it is important to investigate the actions of GLP-1 on different subtypes of thyroid cancer in the future.

  4. Peptide receptor radionuclide therapy with {sup 90}Y-DOTATOC in recurrent meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Bartolomei, Mirco; Bodei, Lisa; De Cicco, Concetta; Grana, Chiara Maria; Baio, Silvia Melania; Arico, Demetrio; Paganelli, Giovanni [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); Cremonesi, Marta [European Institute of Oncology, Division of Medical Physics, Milan (Italy); Botteri, Edoardo [European Institute of Oncology, Division of Epidemiology and Biostatistics, Milan (Italy); Sansovini, Maddalena [Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (I.R.S.T.), Radiometabolic Medicine Division, Meldola (Italy)

    2009-09-15

    Meningiomas are generally benign and in most cases surgery is curative. However, for high-grade histotypes or partially resected tumours, recurrence is fairly common. External beam radiation therapy (EBRT) is usually given in such cases but is not always effective. We assessed peptide receptor radionuclide therapy (PRRT) using {sup 90}Y-DOTATOC in a group of patients with meningioma recurring after standard treatments in all of whom somatostatin receptors were strongly expressed on meningioma cell surfaces. Twenty-nine patients with scintigraphically proven somatostatin subtype 2 receptor-positive meningiomas were enrolled: 14 had benign (grade I), 9 had atypical (grade II) and 6 had malignant (grade III) disease. Patients received intravenous {sup 90}Y-DOTATOC for 2-6 cycles for a cumulative dose in the range of 5-15 GBq. Clinical and neuroradiological evaluations were performed at baseline, during and after PRRT. The treatment was well tolerated in all patients. MRI 3 months after treatment completion showed disease stabilization in 19 of 29 patients (66%) and progressive disease in the remaining 10 (34%). Better results were obtained in patients with grade I meningioma than in those with grade II-III, with median time to progression (from beginning PRRT) of 61 months in the low-grade group and 13 months in the high-grade group. PRRT with {sup 90}Y-DOTATOC can interfere with the growth of meningiomas. The adjuvant role of this treatment, soon after surgery, especially in atypical and malignant histotypes, deserves further investigation. (orig.)

  5. Imidazoline receptors in the heart: a novel target and a novel mechanism of action that involves atrial natriuretic peptides

    Directory of Open Access Journals (Sweden)

    Mukaddam-Daher S.

    2004-01-01

    Full Text Available Chronic stimulation of sympathetic nervous activity contributes to the development and maintenance of hypertension, leading to left ventricular hypertrophy (LVH, arrhythmias and cardiac death. Moxonidine, an imidazoline antihypertensive compound that preferentially activates imidazoline receptors in brainstem rostroventrolateral medulla, suppresses sympathetic activation and reverses LVH. We have identified imidazoline receptors in the heart atria and ventricles, and shown that atrial I1-receptors are up-regulated in spontaneously hypertensive rats (SHR, and ventricular I1-receptors are up-regulated in hamster and human heart failure. Furthermore, cardiac I1-receptor binding decreased after chronic in vivo exposure to moxonidine. These studies implied that cardiac I1-receptors are involved in cardiovascular regulation. The presence of I1-receptors in the heart, the primary site of production of natriuretic peptides, atrial natriuretic peptide (ANP and brain natriuretic peptide (BNP, cardiac hormones implicated in blood pressure control and cardioprotection, led us to propose that ANP may be involved in the actions of moxonidine. In fact, acute iv administration of moxonidine (50 to 150 µg/rat dose-dependently decreased blood pressure, stimulated diuresis and natriuresis and increased plasma ANP and its second messenger, cGMP. Chronic SHR treatment with moxonidine (0, 60 and 120 µg kg-1 h-1, sc for 4 weeks dose-dependently decreased blood pressure, resulted in reversal of LVH and decreased ventricular interleukin 1ß concentration after 4 weeks of treatment. These effects were associated with a further increase in already elevated ANP and BNP synthesis and release (after 1 week, and normalization by 4 weeks. In conclusion, cardiac imidazoline receptors and natriuretic peptides may be involved in the acute and chronic effects of moxonidine.

  6. Targeted Disruption of Guanylyl Cyclase-A/Natriuretic Peptide Receptor-A Gene Provokes Renal Fibrosis and Remodeling in Null Mutant Mice: Role of Proinflammatory Cytokines

    OpenAIRE

    Das, Subhankar; Au, Edward; Krazit, Stephen T.; Pandey, Kailash N.

    2010-01-01

    Binding of atrial and brain natriuretic peptides to guanylyl cyclase-A/natriuretic peptide receptor-A produces second messenger cGMP, which plays an important role in maintaining renal and cardiovascular homeostasis. Mice carrying a targeted disruption of the Npr1 gene coding for guanylyl cyclase-A/natriuretic peptide receptor-A exhibit changes that are similar to those that occur in untreated human hypertension, including elevated blood pressure, cardiac hypertrophy, and congestive heart fai...

  7. A Peptide Antagonist of the ErbB1 Receptor Inhibits Receptor Activation, Tumor Cell Growth and Migration In Vitro and Xenograft Tumor Growth In Vivo

    Science.gov (United States)

    Xu, Ruodan; Povlsen, Gro Klitgaard; Soroka, Vladislav; Bock, Elisabeth; Berezin, Vladimir

    2010-01-01

    The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization. Structural studies have revealed that ErbB receptor dimers are stabilized by receptor–receptor interactions, primarily mediated by a region in the second extracellular domain, termed the “dimerization arm”. The present study is the first biological characterization of a peptide, termed Inherbin3, which constitutes part of the dimerization arm of ErbB3. Inherbin3 binds to the extracellular domains of all four ErbB receptors, with the lowest peptide binding affinity for ErbB4. Inherbin3 functions as an antagonist of epidermal growth factor (EGF)-ErbB1 signaling. We show that Inherbin3 inhibits EGF-induced ErbB1 phosphorylation, cell growth, and migration in two human tumor cell lines, A549 and HN5, expressing moderate and high ErbB1 levels, respectively. Furthermore, we show that Inherbin3 inhibits tumor growth in vivo and induces apoptosis in a tumor xenograft model employing the human non-small cell lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti-cancer therapeutic strategy. PMID:20364069

  8. A Peptide Antagonist of the ErbB1 Receptor Inhibits Receptor Activation, Tumor Cell Growth and Migration In Vitro and Xenograft Tumor Growth In Vivo

    Directory of Open Access Journals (Sweden)

    Ruodan Xu

    2010-01-01

    Full Text Available The epidermal growth factor family of receptor tyrosine kinases (ErbBs plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization. Structural studies have revealed that ErbB receptor dimers are stabilized by receptor–receptor interactions, primarily mediated by a region in the second extracellular domain, termed the “dimerization arm”. The present study is the first biological characterization of a peptide, termed Inherbin3, which constitutes part of the dimerization arm of ErbB3. Inherbin3 binds to the extracellular domains of all four ErbB receptors, with the lowest peptide binding affinity for ErbB4. Inherbin3 functions as an antagonist of epidermal growth factor (EGF-ErbB1 signaling. We show that Inherbin3 inhibits EGF-induced ErbB1 phosphorylation, cell growth, and migration in two human tumor cell lines, A549 and HN5, expressing moderate and high ErbB1 levels, respectively. Furthermore, we show that Inherbin3 inhibits tumor growth in vivo and induces apoptosis in a tumor xenograft model employing the human non-small cell lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti-cancer therapeutic strategy.

  9. Isolation and functional characterization of peptide agonists of PTPRJ, a tyrosine phosphatase receptor endowed with tumor suppressor activity.

    Science.gov (United States)

    Paduano, Francesco; Ortuso, Francesco; Campiglia, Pietro; Raso, Cinzia; Iaccino, Enrico; Gaspari, Marco; Gaudio, Eugenio; Mangone, Graziella; Carotenuto, Alfonso; Bilotta, Anna; Narciso, Domenico; Palmieri, Camillo; Agosti, Valter; Artese, Anna; Gomez-Monterrey, Isabel; Sala, Marina; Cuda, Giovanni; Iuliano, Rodolfo; Perrotti, Nicola; Scala, Giuseppe; Viglietto, Giuseppe; Alcaro, Stefano; Croce, Carlo M; Novellino, Ettore; Fusco, Alfredo; Trapasso, Francesco

    2012-10-19

    PTPRJ is a receptor-type protein tyrosine phosphatase whose expression is strongly reduced in the majority of investigated cancer cell lines and tumor specimens. PTPRJ negatively interferes with mitogenic signals originating from several oncogenic receptor tyrosine kinases, including HGFR, PDGFR, RET, and VEGFR-2. Here we report the isolation and characterization of peptides from a random peptide phage display library that bind and activate PTPRJ. These agonist peptides, which are able to both circularize and form dimers in acqueous solution, were assayed for their biochemical and biological activity on both human cancer cells and primary endothelial cells (HeLa and HUVEC, respectively). Our results demonstrate that binding of PTPRJ-interacting peptides to cell cultures dramatically reduces the extent of both MAPK phosphorylation and total phosphotyrosine levels; conversely, they induce a significant increase of the cell cycle inhibitor p27(Kip1). Moreover, PTPRJ agonist peptides both reduce proliferation and trigger apoptosis of treated cells. Our data indicate that peptide agonists of PTPRJ positively modulate the PTPRJ activity and may lead to novel targeted anticancer therapies.

  10. Effects of glucagon-like peptide-1 receptor agonists on cardiovascular risk factors

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Vilsbøll, Tina; Knop, Filip K

    2017-01-01

    Cardiovascular (CV) disease is the leading cause of death and morbidity in patients with type 2 diabetes. Five CV risk factors (blood pressure, resting heart rate, body weight, cholesterol levels and blood glucose) are monitored routinely as safety and efficacy endpoints in randomized clinical...... trials for diabetes therapies. To determine if different glucagon-like peptide-1 receptor agonists (GLP-1RAs) had varying effects on these CV risk factors, we reviewed 16 head-to-head trials directly comparing GLP-1RAs that included at least one of the five factors. Few trials reported statistical...... effects compared with other GLP-1RAs. These descriptive data indicate that individual GLP-1RAs affect CV risk factors differently, potentially because of their individual pharmacokinetics and/or size. Short-acting GLP-1RAs appeared to result in smaller changes in SBP and total cholesterol compared...

  11. Development of Fluorinated Non-Peptidic Ghrelin Receptor Ligands for Potential Use in Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Rareş-Petru Moldovan

    2017-04-01

    Full Text Available The ghrelin receptor (GhrR is a widely investigated target in several diseases. However, the current knowledge of its role and distribution in the brain is limited. Recently, the small and non-peptidic compound (S-6-(4-bromo-2-fluorophenoxy-3-((1-isopropylpiperidin-3-ylmethyl-2-methylpyrido[3,2-d]pyrimidin-4(3H-one ((S-9 has been described as a GhrR ligand with high binding affinity. Here, we describe the synthesis of fluorinated derivatives, the in vitro evaluation of their potency as partial agonists and selectivity at GhrRs, and their physicochemical properties. These results identified compounds (S-9, (R-9, and (S-16 as suitable parent molecules for 18F-labeled positron emission tomography (PET radiotracers to enable future investigation of GhrR in the brain.

  12. Differential CLE peptide perception by plant receptors implicated from structural and functional analyses of TDIF-TDR interactions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijie; Chakraborty, Sayan; Xu, Guozhou; Kobe, Bostjan

    2017-04-06

    Tracheary Element Differentiation Inhibitory Factor (TDIF) belongs to the family of post-translationally modified CLE (CLAVATA3/embryo surrounding region (ESR)-related) peptide hormones that control root growth and define the delicate balance between stem cell proliferation and differentiation in SAM (shoot apical meristem) or RAM (root apical meristem). In Arabidopsis, Tracheary Element Differentiation Inhibitory Factor Receptor (TDR) and its ligand TDIF signaling pathway is involved in the regulation of procambial cell proliferation and inhibiting its differentiation into xylem cells. Here we present the crystal structures of the extracellular domains (ECD) of TDR alone and in complex with its ligand TDIF resolved at 2.65 Åand 2.75 Å respectively. These structures provide insights about the ligand perception and specific interactions between the CLE peptides and their cognate receptors. Our in vitro biochemical studies indicate that the interactions between the ligands and the receptors at the C-terminal anchoring site provide conserved binding. While the binding interactions occurring at the N-terminal anchoring site dictate differential binding specificities between different ligands and receptors. Our studies will open different unknown avenues of TDR-TDIF signaling pathways that will enhance our knowledge in this field highlighting the receptor ligand interaction, receptor activation, signaling network, modes of action and will serve as a structure function relationship model between the ligand and the receptor for various similar leucine-rich repeat receptor-like kinases (LRR-RLKs).

  13. Comparison of biological stability and metabolism of CCK2 receptor targeting peptides, a collaborative project under COST BM0607.

    NARCIS (Netherlands)

    Ocak, M.; Helbok, A.; Rangger, C.; Peitl, P.K.; Nock, B.A.; Morelli, G.; Eek, A.; Sosabowski, J.K.; Breeman, W.A.; Reubi, J.C.; Decristoforo, C.

    2011-01-01

    PURPOSE: Stability of radiolabelled cholecystokinin 2 (CCK2) receptor targeting peptides has been a major limitation in the use of such radiopharmaceuticals especially for targeted radionuclide therapy applications, e.g. for treatment of medullary thyroid carcinoma (MTC). The purpose of this study

  14. The peptidomimetic Lau-(Lys-βNSpe)6-NH2 antagonizes formyl peptide receptor 2 expressed in mouse neutrophils

    DEFF Research Database (Denmark)

    Skovbakke, Sarah Line; Winther, Malene; Gabl, Michael

    2016-01-01

    The formyl peptide receptor (FPR) gene family has a complex evolutionary history and comprises eight murine members but only three human representatives. To enable translation of results obtained in mouse models of human diseases, more comprehensive knowledge of the pharmacological similarities...

  15. Exenatide, a Glucagon-like Peptide-1 Receptor Agonist, Acutely Inhibits Intestinal Lipoprotein Production in Healthy Humans

    NARCIS (Netherlands)

    Xiao, Changting; Bandsma, Robert H. J.; Dash, Satya; Szeto, Linda; Lewis, Gary F.

    Objective-Incretin-based therapies for the treatment of type 2 diabetes mellitus improve plasma lipid profiles and postprandial lipemia, but their exact mechanism of action remains unclear. Here, we examined the acute effect of the glucagon-like peptide-1 receptor agonist, exenatide, on intestinal

  16. Functionalization of Ruthenium(II) Terpyridine Complexes with Cyclic RGD Peptides To Target Integrin Receptors in Cancer Cells

    NARCIS (Netherlands)

    Hahn, Eva M.; Estrada Ortiz, Natalia; Han, Jiaying; Ferreira, Vera F. C.; Kapp, Tobias G.; Correia, Joao D. G.; Casini, Angela; Kuehn, Fritz E.

    2017-01-01

    The lack of selectivity for cancer cells and the resulting negative impact on healthy tissue is a severe drawback of actual cancer chemotherapy. Tethering of cytotoxic drugs to targeting vectors such as peptides, which recognize receptors overexpressed on the surface of tumor cells, is one possible

  17. Non-peptide oxytocin receptor ligands and hamster circadian wheel running rhythms.

    Science.gov (United States)

    Gannon, Robert L

    2014-10-17

    The synchronization of circadian rhythms in sleep, endocrine and metabolic functions with the environmental light cycle is essential for health, and dysfunction of this synchrony is thought to play a part in the development of many neurological disorders. There is a demonstrable need to develop new therapeutics for the treatment of neurological disorders such as depression and schizophrenia, and oxytocin is currently being investigated for this purpose. There are no published reports describing activity of oxytocin receptor ligands on mammalian circadian rhythms and that, then, is the purpose of this study. Non-peptide oxytocin receptor ligands that cross the blood brain barrier were systemically injected in hamsters to determine their ability to modulate light-induced phase advances and delays of circadian wheel running rhythms. The oxytocin receptor agonist WAY267464 (10 mg/kg) inhibited light induced phase advances of wheel running rhythms by 55%, but had no effect on light-induced phase delays. In contrast, the oxytocin receptor antagonist WAY162720 (10 mg/kg) inhibited light-induced phase delays by nearly 75%, but had no effect on light-induced phase advances. Additionally, WAY162720 was able to antagonize the inhibitory effects of WAY267464 on light-induced phase advances. These results are consistent for a role of oxytocin in the phase-delaying effects of light on circadian activity rhythms early in the night. Therefore, oxytocin may prove to be useful in developing therapeutics for the treatment of mood disorders with a concomitant dysfunction in circadian rhythms. Investigators should also be cognizant that oxytocin ligands may negatively affect circadian rhythms during clinical trials for other conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Dosimetry of exendin-4 based radiotracer for glucagonlike peptide-1 receptor imaging: an initial report

    Science.gov (United States)

    Tomaszuk, M.; Sowa-Staszczak, A.; Lenda-Tracz, W.; Glowa, B.; Pach, D.; Buziak-Bereza, M.; Stefanska, A.; Janota, B.; Pawlak, D.; Mikolajczak, R.; Hubalewska-Dydejczyk, A. B.

    2011-09-01

    Overexpression of glucagonlike peptide-1 (GLP-1) receptors in human tumours is a potential target for future imaging and therapy. The GLP-1 receptor imaging using [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 could be useful in the localization of unknown insulinoma focus. The aim of this study was to present the first experience of our unit with the new radiopharmaceutical and its dose estimates. Imaging studies and dose assessment, according to the MIRD schema and MIRD Pamphlet No.11, were performed for 3 patients (2 with suspicion of insulinoma, 1 with suspected insulinoma recurrence). In the first case suspicion of insulinoma was not confirmed. In the second case localized accumulation of tracer in the pancreas was removed by surgery and the clinical symptoms of insulinoma receded. In the third case, pathological accumulation of tracer was localized and recurrence of insulinoma was confirmed in fusion with CT images. The biological half-time did not exceed 2.7.h. The effective half-time did not exceed 4.8 h. The total-body radiation dose did not exceed 0.0038 mGy/MBq and is comparable with the radiation dose to patient after somatostatin receptor scintigraphy. The highest radiation dose was calculated for kidneys (~ 0.070 mGy/MBq). [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 is a good candidate for clinical GLP-1 receptor imaging studies and appears safe for the patient from radiological safety point of view.

  19. Decreased Hypothalamic Glucagon-Like Peptide-1 Receptor Expression in Type 2 Diabetes Patients.

    Science.gov (United States)

    Ten Kulve, Jennifer S; van Bloemendaal, Liselotte; Balesar, Rawien; IJzerman, Richard G; Swaab, Dick F; Diamant, Michaela; la Fleur, Susanne E; Alkemade, Anneke

    2016-05-01

    Glucagon-like peptide-1 (GLP-1) and GLP-1 receptor agonist treatment in type 2 diabetes (T2DM) reduce blood glucose and food intake. It has been suggested that these effects are partly mediated through central GLP-1 receptors (GLP-1Rs). The rodent and nonhuman primate hypothalamus show clear GLP-1R expression. However, a detailed description of GLP-1R expression in the human hypothalamus is lacking, and it is unknown whether this expression is altered in T2DM patients. The objective of the study was to investigate the GLP-1R distribution in the human postmortem hypothalamus and to determine whether hypothalamic GLP-1R expression is altered in T2DM patients. We investigated the distribution of GLP-1R expression throughout the human hypothalamus by means of in situ hybridization. We also performed quantifications of GLP-1R mRNA expression in two hypothalamic nuclei (ie, the paraventricular nucleus [PVN] and infundibular nucleus [IFN]), comparing patients with T2DM and control subjects. We found that GLP-1R mRNA was expressed in a number of hypothalamic nuclei including the PVN and the IFN, both involved in the regulation of energy metabolism. We observed sporadic colocalization of the GLP-1R in the IFN with the orgexigenic neuropeptide Y, agouti-related peptide, or proopiomelanocortin transcripts. Comparison of GLP-1R mRNA in the PVN and IFN between T2DM patients and control subjects revealed a decreased expression in T2DM patients. Our studies show that GLP-1R is widely expressed throughout the human hypothalamus. The decreased expression of GLP-1R in the PVN and IFN of T2DM patients may be related to the dysregulation of feeding behavior and glucose homeostasis in T2DM.

  20. Glucagon-like peptide-1 receptor ligand interactions: structural cross talk between ligands and the extracellular domain.

    Directory of Open Access Journals (Sweden)

    Graham M West

    Full Text Available Activation of the glucagon-like peptide-1 receptor (GLP-1R in pancreatic β-cells potentiates insulin production and is a current therapeutic target for the treatment of type 2 diabetes mellitus (T2DM. Like other class B G protein-coupled receptors (GPCRs, the GLP-1R contains an N-terminal extracellular ligand binding domain. N-terminal truncations on the peptide agonist generate antagonists capable of binding to the extracellular domain, but not capable of activating full length receptor. The main objective of this study was to use Hydrogen/deuterium exchange (HDX to identify how the amide hydrogen bonding network of peptide ligands and the extracellular domain of GLP-1R (nGLP-1R were altered by binding interactions and to then use this platform to validate direct binding events for putative GLP-1R small molecule ligands. The HDX studies presented here for two glucagon-like peptide-1 receptor (GLP-1R peptide ligands indicates that the antagonist exendin-4[9-39] is significantly destabilized in the presence of nonionic detergents as compared to the agonist exendin-4. Furthermore, HDX can detect stabilization of exendin-4 and exendin-4[9-39] hydrogen bonding networks at the N-terminal helix [Val19 to Lys27] upon binding to the N-terminal extracellular domain of GLP-1R (nGLP-1R. In addition we show hydrogen bonding network stabilization on nGLP-1R in response to ligand binding, and validate direct binding events with the extracellular domain of the receptor for putative GLP-1R small molecule ligands.

  1. Glucagon-like peptide-1 receptor signaling in acinar cells causes growth dependent release of pancreatic enzymes

    DEFF Research Database (Denmark)

    Albrechtsen, Nicolai Jacob Wewer; Albrechtsen, Reidar; Bremholm, l

    2016-01-01

    -like peptide 1 (GLP-1) on the exocrine pancreas. Here, we identify GLP-1 receptors on pancreatic acini and analyze the impact of receptor activation in humans, rodents, isolated acini, and cell lines from the exocrine pancreas. GLP-1 did not directly stimulate amylase or lipase release. However, we saw...... that GLP-1 induces phosphorylation of the epidermal growth factor receptor and activation of Foxo1, resulting in cell growth with concomitant enzyme release. Our work uncovers GLP-1-induced signaling pathways in the exocrine pancreas and suggests that increases in amylase and lipase levels in subjects...

  2. Tachykinin-Related Peptides Share a G Protein-Coupled Receptor with Ion Transport Peptide-Like in the Silkworm Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Chiaki Nagai-Okatani

    Full Text Available Recently, we identified an orphan Bombyx mori neuropeptide G protein-coupled receptor (BNGR-A24 as an ion transport peptide-like (ITPL receptor. BNGR-A24 belongs to the same clade as BNGR-A32 and -A33, which were recently identified as natalisin receptors. Since these three BNGRs share high similarities with known receptors for tachykinin-related peptides (TRPs, we examined whether these BNGRs can function as physiological receptors for five endogenous B. mori TRPs (TK-1-5. In a heterologous expression system, BNGR-A24 acted as a receptor for all five TRPs. In contrast, BNGR-A32 responded only to TK-5, and BNGR-A33 did not respond to any of the TRPs. These findings are consistent with recent studies on the ligand preferences for B. mori natalisins. Furthermore, we evaluated whether the binding of ITPL and TRPs to BNGR-A24 is competitive by using a Ca2+ imaging assay. Concomitant addition of a TRP receptor antagonist, spantide I, reduced the responses of BNGR-A24 not only to TK-4 but also to ITPL. The results of a binding assay using fluorescent-labeled BNGR-A24 and ligands demonstrated that the binding of ITPL to BNGR-A24 was inhibited by TK-4 as well as by spantide I, and vice versa. In addition, the ITPL-induced increase in cGMP levels of BNGR-A24-expressing BmN cells was suppressed by the addition of excess TK-4 or spantide I. The intracellular levels of cAMP and cGMP, as second messenger candidates of the TRP signaling, were not altered by the five TRPs, suggesting that these peptides act via different signaling pathways from cAMP and cGMP signaling at least in BmN cells. Taken together, the present findings suggest that ITPL and TRPs are endogenous orthosteric ligands of BNGR-A24 that may activate discrete signaling pathways. This receptor, which shares orthosteric ligands, may constitute an important model for studying ligand-biased signaling.

  3. Interactions of zebrafish peptide YYb with the neuropeptide Y-family receptors Y4, Y7, Y8a and Y8b

    Directory of Open Access Journals (Sweden)

    Görel eSundström

    2013-03-01

    Full Text Available The neuropeptide Y (NPY system influences numerous physiological functions including feeding behavior, endocrine regulation, and cardiovascular regulation. In jawed vertebrates it consists of 3-4 peptides and 4-7 receptors. Teleost fishes have unique duplicates of NPY and PYY as well as the Y8 receptor. In the zebrafish, the NPY system consists of the peptides NPYa, PYYa, and PYYb (NPYb appears to have been lost and at least seven NPY receptors: Y1, Y2, Y2-2, Y4, Y7, Y8a and Y8b. Previously PYYb binding has been reported for Y2 and Y2-2. To search for peptide-receptor preferences, we have investigated PYYb binding to four of the remaining receptors and compared with NPYa and PYYa. Taken together, the most striking observations are that PYYa displays reduced affinity for Y2 (3 nM compared to the other peptides and receptors and that all three peptides have higher affinity for Y4 (0.028-0.034 nM than for the other five receptors. The strongest peptide preference by any receptor selectivity is the one previously reported for PYYb by the Y2 receptor, as compared to NPY and PYYa. These affinity differences may be helpful to elucidate specific details of peptide-receptor interactions. Also, we have investigated the level of mRNA expression in different organs using qPCR. All peptides and receptors have higher expression in heart, kidney and brain. These quantitative aspects on receptor affinities and mRNA distribution help provide a more complete picture of the NPY system.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-22

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

  5. Flagellin peptide flg22 gains access to long-distance trafficking in Arabidopsis via its receptor, FLS2

    Energy Technology Data Exchange (ETDEWEB)

    Jelenska, Joanna; Davern, Sandra M.; Standaert, Robert F.; Mirzadeh, Saed; Greenberg, Jean T.

    2017-03-01

    Diverse pathogen-derived molecules, such as bacterial flagellin and its conserved peptide flg22, are recognized in plants via plasma membrane receptors and induce both local and systemic immune responses. The fate of such ligands was unknown: whether and by what mechanism(s) they enter plant cells and whether they are transported to distal tissues. We used biologically active fluorophore and radiolabeled peptides to establish that flg22 moves to distal organs with the closest vascular connections. Remarkably, entry into the plant cell via endocytosis together with the FLS2 receptor is needed for delivery to vascular tissue and long-distance transport of flg22. This contrasts with known routes of long distance transport of other non-cell-permeant molecules in plants, which require membrane-localized transporters for entry to vascular tissue. Thus, a plasma membrane receptor acts as a transporter to enable access of its ligand to distal trafficking routes.

  6. The Peptide PnPP-19, a Spider Toxin Derivative, Activates μ-Opioid Receptors and Modulates Calcium Channels

    Directory of Open Access Journals (Sweden)

    Ana C. N. Freitas

    2018-01-01

    Full Text Available The synthetic peptide PnPP-19 comprehends 19 amino acid residues and it represents part of the primary structure of the toxin δ-CNTX-Pn1c (PnTx2-6, isolated from the venom of the spider Phoneutria nigriventer. Behavioural tests suggest that PnPP-19 induces antinociception by activation of CB1, μ and δ opioid receptors. Since the peripheral and central antinociception induced by PnPP-19 involves opioid activation, the aim of this work was to identify whether this synthetic peptide could directly activate opioid receptors and investigate the subtype selectivity for μ-, δ- and/or κ-opioid receptors. Furthermore, we also studied the modulation of calcium influx driven by PnPP-19 in dorsal root ganglion neurons, and analyzed whether this modulation was opioid-mediated. PnPP-19 selectively activates μ-opioid receptors inducing indirectly inhibition of calcium channels and hereby impairing calcium influx in dorsal root ganglion (DRG neurons. Interestingly, notwithstanding the activation of opioid receptors, PnPP-19 does not induce β-arrestin2 recruitment. PnPP-19 is the first spider toxin derivative that, among opioid receptors, selectively activates μ-opioid receptors. The lack of β-arrestin2 recruitment highlights its potential for the design of new improved opioid agonists.

  7. Atrial natriuretic peptide receptor heterogeneity and effects on cyclic GMP accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Leitman, D.C.

    1988-01-01

    The effects of atrial natriuretic peptide (ANP), oxytocin (OT) and vasopressin (AVP) on guanylate cyclase activity and cyclic GMP accumulation were examined, since these hormones appear to be intimately associated with blood pressure and intravascular volume homeostasis. ANP was found to increase cyclic GMP accumulation in ten cell culture systems, which were derived from blood vessels, adrenal cortex, kidney, lung, testes and mammary gland. ANP receptors were characterized in intact cultured cells using {sup 125}I-ANP{sub 8-33}. Specific {sup 125}I-ANP binding was saturable and of high affinity. Scratchard analysis of the binding data for all cell types exhibited a straight line, indicating that these cells possessed a single class of binding sites. Despite the presence of linear Scatchard plots, these studies demonstrated that cultured cells possess two functionally and physically distinct ANP-binding sites. Most of the ANP-binding sites in cultured cells have a molecular size of 66,000 daltons under reducing conditions. The identification of cultured cell types in which hormones (ANP and oxytocin) regulate guanylate cyclase activity and increase cyclic GMP synthesis will provide valuable systems to determine the mechanisms of hormone-receptor coupling to guanylate cyclase and the cellular processes regulated by cyclic GMP.

  8. AVE 0991, a non-peptide Mas-receptor agonist, facilitates penile erection.

    Science.gov (United States)

    da Costa Gonçalves, Andrey C; Fraga-Silva, Rodrigo A; Leite, Romulo; Santos, Robson A S

    2013-03-01

    The renin-angiotensin system plays a crucial role in erectile function. It has been shown that elevated levels of angiotensin II contribute to the development of erectile dysfunction both in humans and in aminals. On the contrary, the heptapeptide angiotensin-(1-7) appears to mediate penile erection by activation of the Mas receptor. Recently, we have shown that the erectile function of Mas gene-deleted mice was substantially reduced, which was associated with a marked increase in fibrous tissue in the corpus cavernosum. We have hypothesized that the synthetic non-peptide Mas agonist, AVE 0991, would potentiate penile erectile function. We showed that intracavernosal injection of AVE 0991 potentiated the erectile response of anaesthetized Wistar rats, measured as the ratio between corpus cavernosum pressure and mean arterial pressure, upon electrical stimulation of the major pelvic ganglion. The facilitatory effect of AVE 0991 on erectile function was dose dependent and completely blunted by the nitric oxide synthesis inhibitor, l-NAME. Importantly, concomitant intracavernosal infusion of the specific Mas receptor blocker, A-779, abolished the effect of AVE 0991. We demonstrated that AVE 0991 potentiates the penile erectile response through Mas in an NO-dependent manner. Importantly, these results suggest that Mas agonists, such as AVE 0991, might have significant therapeutic benefits for the treatment of erectile dysfunction.

  9. Defective Natriuretic Peptide Receptor Signaling in Skeletal Muscle Links Obesity to Type 2 Diabetes.

    Science.gov (United States)

    Coué, Marine; Badin, Pierre-Marie; Vila, Isabelle K; Laurens, Claire; Louche, Katie; Marquès, Marie-Adeline; Bourlier, Virginie; Mouisel, Etienne; Tavernier, Geneviève; Rustan, Arild C; Galgani, Jose E; Joanisse, Denis R; Smith, Steven R; Langin, Dominique; Moro, Cedric

    2015-12-01

    Circulating natriuretic peptide (NP) levels are reduced in obesity and predict the risk of type 2 diabetes (T2D). Since skeletal muscle was recently shown as a key target tissue of NP, we aimed to investigate muscle NP receptor (NPR) expression in the context of obesity and T2D. Muscle NPRA correlated positively with whole-body insulin sensitivity in humans and was strikingly downregulated in obese subjects and recovered in response to diet-induced weight loss. In addition, muscle NP clearance receptor (NPRC) increased in individuals with impaired glucose tolerance and T2D. Similar results were found in obese diabetic mice. Although no acute effect of brain NP (BNP) on insulin sensitivity was observed in lean mice, chronic BNP infusion improved blood glucose control and insulin sensitivity in skeletal muscle of obese and diabetic mice. This occurred in parallel with a reduced lipotoxic pressure in skeletal muscle due to an upregulation of lipid oxidative capacity. In addition, chronic NP treatment in human primary myotubes increased lipid oxidation in a PGC1α-dependent manner and reduced palmitate-induced lipotoxicity. Collectively, our data show that activation of NPRA signaling in skeletal muscle is important for the maintenance of long-term insulin sensitivity and has the potential to treat obesity-related metabolic disorders. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  10. Activation of spinal glucagon-like peptide-1 receptors specifically suppresses pain hypersensitivity.

    Science.gov (United States)

    Gong, Nian; Xiao, Qi; Zhu, Bin; Zhang, Chang-Yue; Wang, Yan-Chao; Fan, Hui; Ma, Ai-Niu; Wang, Yong-Xiang

    2014-04-09

    This study aims to identify the inhibitory role of the spinal glucagon like peptide-1 receptor (GLP-1R) signaling in pain hypersensitivity and its mechanism of action in rats and mice. First, GLP-1Rs were identified to be specifically expressed on microglial cells in the spinal dorsal horn, and profoundly upregulated after peripheral nerve injury. In addition, intrathecal GLP-1R agonists GLP-1(7-36) and exenatide potently alleviated formalin-, peripheral nerve injury-, bone cancer-, and diabetes-induced hypersensitivity states by 60-90%, without affecting acute nociceptive responses. The antihypersensitive effects of exenatide and GLP-1 were completely prevented by GLP-1R antagonism and GLP-1R gene knockdown. Furthermore, exenatide evoked β-endorphin release from both the spinal cord and cultured microglia. Exenatide antiallodynia was completely prevented by the microglial inhibitor minocycline, β-endorphin antiserum, and opioid receptor antagonist naloxone. Our results illustrate a novel spinal dorsal horn microglial GLP-1R/β-endorphin inhibitory pathway in a variety of pain hypersensitivity states.

  11. Peptide-MHC-based nanomedicines for autoimmunity function as T-cell receptor microclustering devices

    Science.gov (United States)

    Singha, Santiswarup; Shao, Kun; Yang, Yang; Clemente-Casares, Xavier; Solé, Patricia; Clemente, Antonio; Blanco, Jesús; Dai, Qin; Song, Fayi; Liu, Shang Wan; Yamanouchi, Jun; Umeshappa, Channakeshava Sokke; Nanjundappa, Roopa Hebbandi; Detampel, Pascal; Amrein, Matthias; Fandos, César; Tanguay, Robert; Newbigging, Susan; Serra, Pau; Khadra, Anmar; Chan, Warren C. W.; Santamaria, Pere

    2017-07-01

    We have shown that nanoparticles (NPs) can be used as ligand-multimerization platforms to activate specific cellular receptors in vivo. Nanoparticles coated with autoimmune disease-relevant peptide-major histocompatibility complexes (pMHC) blunted autoimmune responses by triggering the differentiation and expansion of antigen-specific regulatory T cells in vivo. Here, we define the engineering principles impacting biological activity, detail a synthesis process yielding safe and stable compounds, and visualize how these nanomedicines interact with cognate T cells. We find that the triggering properties of pMHC-NPs are a function of pMHC intermolecular distance and involve the sustained assembly of large antigen receptor microclusters on murine and human cognate T cells. These compounds show no off-target toxicity in zebrafish embryos, do not cause haematological, biochemical or histological abnormalities, and are rapidly captured by phagocytes or processed by the hepatobiliary system. This work lays the groundwork for the design of ligand-based NP formulations to re-program in vivo cellular responses using nanotechnology.

  12. Detection and distribution of opioid peptide receptors in porcine myocardial tissue.

    Science.gov (United States)

    Theisen, Marc Michael; Schlottmann, Silke; August, Christian; Herzog, Christine; Theilmeier, Gregor; Maas, Matthias; Blumenstiel, Jonas Martin; Weber, Thomas Peter; Van Aken, Hugo Karel; Kaerlein, Kristoffer Tim

    2014-06-01

    There is growing evidence that opioid peptide receptors (OPRs) play an important role in cardiovascular function. Many studies have been conducted in swine, in view of their anatomic and physiologic similarities to humans. Until now, the presence and particularly distribution of OPRs has been unclear. Porcine myocardial tissue was obtained from both the left and right atria and ventricles. Expression of mRNA for μ-, δ- and κ-OPR was determined by reverse transcription PCR. OPR proteins were detected by Western blot, distribution and cellular location were identified using immunohistochemistry. Homogenous expression of mRNA and protein for δ- and κ-OPRs were demonstrated in all porcine myocardial tissue tested, whereas expression of μ-OPR mRNA was not demonstrated in any of the tissues tested. This study demonstrates the expression of δ- and κ-OPRs in porcine myocardial tissue. No differences in distribution of δ- and κ-OPRs were found between the four heart cavities. Modulation of cardiac function by δ- and κ-OPR agonists or antagonists is therefore possible, while μ-OPR-mediated direct cardiac effects appear unlikely, due to nonexpression of the receptor. This study demonstrates that porcine studies can further elucidate the role of OPRs in cardiac (patho-)physiology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Regulation of calcitonin gene-related peptide receptors in the rat uterus during pregnancy and labor and by progesterone.

    Science.gov (United States)

    Yallampalli, C; Gangula, P R; Kondapaka, S; Fang, L; Wimalawansa, S

    1999-10-01

    Calcitonin gene-related peptide (CGRP) is a potent smooth muscle relaxant in a variety of tissues. We recently demonstrated that CGRP relaxes uterine tissue during pregnancy but not during labor. In the present study we examined whether uterine (125)I-CGRP binding and immunoreactive CGRP receptors are regulated by pregnancy and labor and by sex steroid hormones. We found that (125)I-CGRP binding to membrane preparations from uteri was elevated during pregnancy and decreased during labor and postpartum. Changes in immunoreactive CGRP receptors were similar to the changes in (125)I-CGRP binding in these tissues, suggesting pregnancy-dependent regulation of CGRP receptor protein. CGRP receptors were elevated by Day 7 of gestation, and a precipitous decrease in these receptors occurred on Day 22 of gestation prior to the onset of labor. Both (125)I-CGRP-binding and immunofluorescence studies indicated that CGRP receptors were localized to myometrial cells. Hormonal control of uterine CGRP receptors was assessed by the use of antiprogesterone RU-486, progesterone, and estradiol-17beta. RU-486 induced a decrease in uterine CGRP receptors during pregnancy (Day 19). On the other hand, progesterone prevented the fall in uterine CGRP receptors at term (Day 22). In addition, progesterone also increased uterine CGRP receptors in nonpregnant, ovariectomized rats, while estradiol had no effects. These hormone-induced changes in uterine CGRP receptors were demonstrated by (125)I-CGRP-binding, Western immunoblotting, and immunolocalization methods. These results indicate that CGRP receptors and CGRP binding in the rat uterus are increased with pregnancy and decreased at term. These receptors are localized to the myometrial cells, and progesterone is required for maintaining CGRP receptors in the rat uterus. Thus, the inhibitory effects of CGRP on uterine contractility are mediated through the changes in CGRP receptors and may play a role in uterine quiescence during pregnancy.

  14. Involvement of formyl peptide receptors in receptor for advanced glycation end products (RAGE - and amyloid beta 1-42-induced signal transduction in glial cells

    Directory of Open Access Journals (Sweden)

    Slowik Alexander

    2012-11-01

    Full Text Available Abstract Background Recent studies suggest that the chemotactic G-protein-coupled-receptor (GPCR formyl-peptide-receptor-like-1 (FPRL1 and the receptor-for-advanced-glycation-end-products (RAGE play an important role in the inflammatory response involved in neurodegenerative disorders such as Alzheimer’s disease (AD. Therefore, the expression and co-localisation of mouse formyl peptide receptor (mFPR 1 and 2 as well as RAGE in an APP/PS1 transgenic mouse model using immunofluorescence and real-time RT-PCR were analysed. The involvement of rat or human FPR1/FPRL1 (corresponds to mFPR1/2 and RAGE in amyloid-β 1–42 (Aβ1-42-induced signalling were investigated by extracellular signal regulated kinase 1/2 (ERK1/2 phosphorylation. Furthermore, the cAMP level in primary rat glial cells (microglia and astrocytes and transfected HEK 293 cells was measured. Formyl peptide receptors and RAGE were inhibited by a small synthetic antagonist WRW4 and an inactive receptor variant delta-RAGE, lacking the intracytoplasmatic domains. Results We demonstrated a strong increase of mFPR1/2 and RAGE expression in the cortex and hippocampus of APP/PS1 transgenic mice co-localised to the glial cells. In addition, the Aβ1-42-induced signal transduction is dependant on FPRL1, but also on FPR1. For the first time, we have shown a functional interaction between FPRL1/FPR1 and RAGE in RAGE ligands S100B- or AGE-mediated signalling by ERK1/2 phosphorylation and cAMP level measurement. In addition a possible physical interaction between FPRL1 as well as FPR1 and RAGE was shown with co-immunoprecipitation and fluorescence microscopy. Conclusions The results suggest that both formyl peptide receptors play an essential role in Aβ1-42-induced signal transduction in glial cells. The interaction with RAGE could explain the broad ligand spectrum of formyl peptide receptors and their important role for inflammation and the host defence against infections.

  15. Relaxin-Family Peptide Receptors 1 and 2 Are Fully Functional in the Bovine

    Directory of Open Access Journals (Sweden)

    Yanzhenzi Dai

    2017-06-01

    Full Text Available In most mammals the peptide hormone relaxin is a key physiological component regulating early pregnancy and birth. However, synteny analysis shows that the gene encoding ovarian relaxin-2 is deleted in cows and sheep. While, these ruminants appear to exhibit a relaxin-like physiology, as in other mammals, until now a molecular understanding of this has been lacking. Cloning and expression analysis of the cognate bovine receptor for relaxin, RXFP1, as well as of the structurally related receptor, RXFP2, in female tissues, shows that these are expressed in a similar way to other mammals. RXFP1 transcripts are found in ovarian theca cells, endometrium, and myometrium, whereas RXFP2 transcripts are expressed in ovarian theca cells, oocytes, as well as in myometrium. Transfection of receptor-expressing gene constructs into HEK293 cells indicates that bovine RXFP1 has a greater EC50 at 10–50 nM for porcine or human relaxin, compared to human RXFP1. For bovine RXFP2, in contrast, the EC50 is <1 nM for its cognate ligand, bovine INSL3, but also 10–30 nM for porcine or human relaxin. Functional analysis shows that bovine myometrial cells are able to respond to exogenous relaxin and INSL3 with a significant increase in cAMP. Although expressing mRNA for both RXFP1 and RXFP2, bovine follicular theca cells only respond to INSL3 with a dose-dependent increase in cAMP. Altogether the results suggest that the cow is able to compensate for the missing hormone, and moreover imply that relaxin analogs could offer an important therapeutic option in treating female ruminant infertility.

  16. Thermodynamics of T cell receptorpeptide/MHC interactions: progress and opportunities

    Science.gov (United States)

    Armstrong, Kathryn M.; Insaidoo, Francis K.; Baker, Brian M.

    2013-01-01

    αβ T cell receptors (TCR) recognize peptide antigens presented by class I or class II major histocompatibility complex molecules (pMHC). Here we review the use of thermodynamic measurements in the study of TCR-pMHC interactions, with attention to the diversity in binding thermodynamics and how this is related to the variation in TCR-pMHC interfaces. We show that there is no enthalpic or entropic signature for TCR binding; rather, enthalpy and entropy changes vary in a compensatory manner that reflects a narrow free energy window for the interactions that have been characterized. Binding enthalpy and entropy changes do not correlate with structural features such as buried surface area or the number of hydrogen bonds within TCR-pMHC interfaces, possibly reflecting the myriad of contributors to binding thermodynamics, but likely also reflecting a reliance on van’t Hoff over calorimetric measurements and the unaccounted influence of equilibria linked to binding. TCR-pMHC binding heat capacity changes likewise vary considerably. In some cases the heat capacity changes are consistent with conformational differences between bound and free receptors, but there is little data indicating these conformational differences represent the need to organize commonly disordered CDR loops. In this regard, we discuss how thermodynamics may provide additional insight into conformational changes occurring upon TCR binding. Finally, we highlight opportunities for the further use of thermodynamic measurements in the study of TCR-pMHC interactions, not only for understanding TCR binding in general, but for understanding specifics of individual interactions and the engineering of T cell receptors with desired molecular recognition properties. PMID:18496839

  17. Signal transduction by the formyl peptide receptor. Studies using chimeric receptors and site-directed mutagenesis define a novel domain for interaction with G-proteins.

    Science.gov (United States)

    Amatruda, T T; Dragas-Graonic, S; Holmes, R; Perez, H D

    1995-11-24

    The binding of small peptide ligands to high affinity chemoattractant receptors on the surface of neutrophils and monocytes leads to activation of heterotrimeric G-proteins, stimulation of phosphatidylinositol-phospholipase C (PI-PLC), and subsequently to the inflammatory response. It was recently shown (Amatruda, T. T., Gerard, N. P., Gerard, C., and Simon, M. I. (1993) J. Biol. Chem. 268, 10139-10144) that the receptor for the chemoattractant peptide C5a specifically interacts with G alpha 16, a G-protein alpha subunit of the Gq class, to trigger ligand-dependent stimulation of PI-PLC in transfected cells. In order to further characterize this chemoattractant peptide signal transduction pathway, we transfected cDNAs encoding the formylmethionylleucylphenylalanine receptor (fMLPR) into COS cells and measured the production of inositol phosphates. Ligand-dependent activation of PI-PLC was seen in COS cells transfected with the fMLPR and G alpha 16 and stimulated with fMLP but not in cells transfected with receptor alone or with receptor plus G alpha q. Chimeric receptors in which the N-terminal extracellular domain, the second intracellular domain, or the intracellular C-terminal tail of the fMLP receptor was replaced with C5a receptor domains (Perez, H. D., Holmes, R., Vilander, L. R., Adams, R. R., Manzana, W., Jolley, D., and Andrews, W. H. (1993) J. Biol. Chem. 268, 2292-2295) were capable of ligand-dependent activation of PI-PLC when co-transfected with G alpha 16. A chimeric receptor exchanging the first intracellular domain of the fMLPR was constitutively activated, stimulating PI-PLC in the absence of ligand. Constitutive activation of PI-PLC, to a level 233% of that seen in cells transfected with wild-type fMLP receptors, was dependent on G alpha 16. Site-directed mutagenesis of the first intracellular domain of the fMLPR (amino acids 54-62) reveals this to be a domain necessary for ligand-dependent activation of G alpha 16. These results suggest that

  18. Beyond glucose lowering: glucagon-like peptide-1 receptor agonists, body weight and the cardiovascular system.

    Science.gov (United States)

    Vergès, B; Bonnard, C; Renard, E

    2011-12-01

    Glucagon-like peptide-1 (GLP-1) belongs to the incretin hormone family: in the presence of elevated blood glucose, it stimulates insulin secretion and inhibits glucagon production. In addition, GLP-1 slows gastric emptying. GLP-1 secretion has also been reported to potentially affect patients with type 2 diabetes (T2DM) compared with non-diabetics and, as enzymatic inactivation by dipeptidyl peptidase-4 (DPP-4) shortens the GLP-1 half-life to a few minutes, GLP-1 receptor agonists such as exenatide twice daily (BID) and liraglutide have been developed, and have become part of the management of patients with T2DM. This review focuses on the potential beneficial effects of these compounds beyond those associated with improvements in blood glucose control and weight loss, including changes in the cardiovascular and central nervous systems. This was a state-of-the-art review of the literature to evaluate the relationships between GLP-1, GLP-1 receptor agonists, weight and the cardiovascular system. GLP-1 receptor agonists improve glucose control and do not significantly increase the risk of hypoglycaemia. Also, this new class of antidiabetic drugs was shown to favour weight loss. Mechanisms may involve central action, direct action by reduction of food intake and probably indirect action through slowing of gastric emptying. The relative importance of each activity remains unclear. Weight loss may improve cardiovascular outcomes in patients with T2DM, although GLP-1 receptor agonists may have other direct and indirect effects on the cardiovascular system. Reductions in myocardial infarct size and improvements in cardiac function have been seen in animal models. Beneficial changes in cardiac function were also demonstrated in patients with myocardial infarcts or heart failure. Indirect effects could involve a reduction in blood pressure and potential effects on oxidation. However, the mechanisms involved in the pleiotropic effects of GLP-1 receptor agonists have yet to

  19. Receptor activity-modifying protein dependent and independent activation mechanisms in the coupling of calcitonin gene-related peptide and adrenomedullin receptors to Gs.

    Science.gov (United States)

    Woolley, Michael J; Reynolds, Christopher A; Simms, John; Walker, Christopher S; Mobarec, Juan Carlos; Garelja, Michael L; Conner, Alex C; Poyner, David R; Hay, Debbie L

    2017-10-15

    Calcitonin gene-related peptide (CGRP) or adrenomedullin (AM) receptors are heteromers of the calcitonin receptor-like receptor (CLR), a class B G protein-coupled receptor, and one of three receptor activity-modifying proteins (RAMPs). How CGRP and AM activate CLR and how this process is modulated by RAMPs is unclear. We have defined how CGRP and AM induce Gs-coupling in CLR-RAMP heteromers by measuring the effect of targeted mutagenesis in the CLR transmembrane domain on cAMP production, modeling the active state conformations of CGRP and AM receptors in complex with the Gs C-terminus and conducting molecular dynamics simulations in an explicitly hydrated lipidic bilayer. The largest effects on receptor signaling were seen with H295A5.40b, I298A5.43b, L302A5.47b, N305A5.50b, L345A6.49b and E348A6.52b, F349A6.53b and H374A7.47b (class B numbering in superscript). Many of these residues are likely to form part of a group in close proximity to the peptide binding site and link to a network of hydrophilic and hydrophobic residues, which undergo rearrangements to facilitate Gs binding. Residues closer to the extracellular loops displayed more pronounced RAMP or ligand-dependent effects. Mutation of H3747.47b to alanine increased AM potency 100-fold in the CGRP receptor. The molecular dynamics simulation showed that TM5 and TM6 pivoted around TM3. The data suggest that hydrophobic interactions are more important for CLR activation than other class B GPCRs, providing new insights into the mechanisms of activation of this class of receptor. Furthermore the data may aid in the understanding of how RAMPs modulate the signaling of other class B GPCRs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Rapakinin, an anti-hypertensive peptide derived from rapeseed protein, dilates mesenteric artery of spontaneously hypertensive rats via the prostaglandin IP receptor followed by CCK(1) receptor.

    Science.gov (United States)

    Yamada, Yuko; Iwasaki, Masashi; Usui, Hachiro; Ohinata, Kousaku; Marczak, Ewa D; Lipkowski, Andrzej W; Yoshikawa, Masaaki

    2010-05-01

    The anti-hypertensive peptide Arg-Ile-Tyr, which was isolated based on its inhibitory activity (IC(50)=28microM) for angiotensin I-converting enzyme (ACE) from the subtilisin digest of rapeseed protein, exhibited vasorelaxing activity (EC(50)=5.1microM) in an endothelium-dependent manner in the mesenteric artery of spontaneously hypertensive rats (SHRs). We named the peptide rapakinin. ACE inhibitors are reported to induce nitric oxide (NO)-dependent vasorelaxation by elevating the endogenous bradykinin level; however, the vasorelaxation induced by 10microM of rapakinin was blocked only insignificantly by HOE140 or N(G)-nitro-l-arginine methyl ester (l-NAME), antagonists of bradykinin B(2) receptor and an inhibitor of NO synthase, respectively. On the other hand, the vasorelaxation induced by 10microM rapakinin was significantly blocked by indomethacin and CAY10441, a cyclooxygenase (COX) inhibitor and an antagonist of the IP receptor, respectively. The vasorelaxing activity of rapakinin was also blocked by lorglumide, an antagonist of the cholecystokinin (CCK) CCK(1) receptor, although rapakinin has no affinity for the IP and CCK(1) receptors. The vasorelaxation induced by 10microM iloprost, an IP receptor agonist, was also blocked by lorglumide, suggesting that CCK-CCK(1) receptor system is activated downstream of the PGI(2)-IP receptor system. The anti-hypertensive activity of rapakinin after oral administration in SHRs was also blocked by CAY10441 and lorglumide. These results suggest that the anti-hypertensive activity of rapakinin might be mediated mainly by the PGI(2)-IP receptor, followed by CCK-CCK(1) receptor-dependent vasorelaxation. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  1. A new strategy for the preparation of peptide-targeted technetium and rhenium radiopharmaceuticals. The automated solid-phase synthesis, characterization, labeling, and screening of a peptide-ligand library targeted at the formyl peptide receptor.

    Science.gov (United States)

    Stephenson, Karin A; Banerjee, Sangeeta Ray; Sogbein, Oyebola O; Levadala, Murali K; McFarlane, Nicole; Boreham, Douglas R; Maresca, Kevin P; Babich, John W; Zubieta, Jon; Valliant, John F

    2005-01-01

    A new solid-phase synthetic methodology was developed that enables libraries of peptide-based Tc(I)/Re(I) radiopharmaceuticals to be prepared using a conventional automated peptide synthesizer. Through the use of a tridentate ligand derived from N-alpha-Fmoc-l-lysine, which we refer to as a single amino acid chelate (SAAC), a series of 12 novel bioconjugates [R-NH(CO)ZLF(SAAC)G, R = ethyl, isopropyl, n-propyl, tert-butyl, n-butyl, benzyl; Z = Met, Nle] that are designed to target the formyl peptide receptor (FPR) were prepared. Construction of the library was carried out in a multiwell format on an Advanced ChemTech 348 peptide synthesizer where multi-milligram quantities of each peptide were isolated in high purity without HPLC purification. After characterization, the library components were screened for their affinity for the FPR receptor using flow cytometry where the K(d) values were found to be in the low micromolar range (0.5-3.0 microM). Compound 5j was subsequently labeled with (99m)Tc(I) and the product isolated in high radiochemical yield using a simple Sep-Pak purification procedure. The retention time of the labeled compound matched that of the fully characterized Re-analogue which was prepared through the use of the same solid-phase synthesis methodology that was used to construct the library. The work reported here is a rare example of a method by which libraries of peptide-ligand conjugates and their rhenium complexes can be prepared.

  2. Inhibition of plasminogen activator inhibitor-1 binding to endocytosis receptors of the low density lipoprotein receptor family by a peptide isolated from a phage displayed library

    DEFF Research Database (Denmark)

    Jensen, Jan K.; Malmendal, Anders; Schiøtt, Birgit

    2006-01-01

    The functions of the serpin plasminogen activator inhibitor-1 (PAI-1) are based on molecular interactions with its target proteases urokinase-type and tissue-type plasminogen activator (uPA and tPA), with vitronectin, and with endocytosis receptors of the low density lipoprotein family. Understan......The functions of the serpin plasminogen activator inhibitor-1 (PAI-1) are based on molecular interactions with its target proteases urokinase-type and tissue-type plasminogen activator (uPA and tPA), with vitronectin, and with endocytosis receptors of the low density lipoprotein family...... (DVPCFGWCQDA) was determined by NMR. A binding site in the so-called flexible joint region of PAI-1 was suggested by molecular modelling and validated through binding studies with various competitors and site-directed mutagenesis of PAI-1. The peptide with an N-terminal biotin inhibited the binding of the u......PA-PAI-1 complex to the endocytosis receptors low density lipoprotein receptor-related protein (LRP-1A) and very low density lipoprotein receptor (VLDLR) in vitro and inhibited endocytosis of the uPA-PAI-1 complex in U937 cells. We conclude that the isolated peptide represents a novel approach...

  3. Functional characterization by heterologous expression of a novel cloned tachykinin peptide receptor.

    OpenAIRE

    Donaldson, L F; Haskell, C A; Hanley, M R

    1996-01-01

    An orphan receptor resembling the neurokinin 3 tachykinin receptor (NK3), initially claimed to be an atypical opioid receptor, is shown herein to respond potently to the physiological NK3 receptor ligand, neurokinin B. This 'NK4' receptor did not give functional responses in Xenopus oocytes to opioid agonists. However, NK4 receptor activation was inhibited by nanomolar concentrations of dynorphin. The NK4 receptor is therefore a tachykinin receptor which is functionally antagonized by an endo...

  4. Molecular Characterisation of Small Molecule Agonists Effect on the Human Glucagon Like Peptide-1 Receptor Internalisation.

    Directory of Open Access Journals (Sweden)

    Aiysha Thompson

    Full Text Available The glucagon-like peptide receptor (GLP-1R, which is a G-protein coupled receptor (GPCR, signals through both Gαs and Gαq coupled pathways and ERK phosphorylation to stimulate insulin secretion. The aim of this study was to determine molecular details of the effect of small molecule agonists, compounds 2 and B, on GLP-1R mediated cAMP production, intracellular Ca2+ accumulation, ERK phosphorylation and its internalisation. In human GLP-1R (hGLP-1R expressing cells, compounds 2 and B induced cAMP production but caused no intracellular Ca2+ accumulation, ERK phosphorylation or hGLP-1R internalisation. GLP-1 antagonists Ex(9-39 and JANT-4 and the orthosteric binding site mutation (V36A in hGLP-1R failed to inhibit compounds 2 and B induced cAMP production, confirming that their binding site distinct from the GLP-1 binding site on GLP-1R. However, K334A mutation of hGLP-1R, which affects Gαs coupling, inhibited GLP-1 as well as compounds 2 and B induced cAMP production, indicating that GLP-1, compounds 2 and B binding induce similar conformational changes in the GLP-1R for Gαs coupling. Additionally, compound 2 or B binding to the hGLP-1R had significantly reduced GLP-1 induced intracellular Ca2+ accumulation, ERK phosphorylation and hGLP-1R internalisation. This study illustrates pharmacology of differential activation of GLP-1R by GLP-1 and compounds 2 and B.

  5. C-terminus of a hexapeptidic ghrelin receptor inverse agonist can switch peptide behavior from inverse agonism to agonism.

    Science.gov (United States)

    Els-Heindl, Sylvia; Bellmann-Sickert, Kathrin; Beck-Sickinger, Annette G

    2016-01-01

    Subtle changes in the sequence at the N-terminus and in the aromatic core of hexapeptidic ghrelin receptor inverse agonists can switch behavior from inverse agonism to agonism, but the C-terminal role of the sequence is unclear. Thus, analogs of the ghrelin receptor inverse agonist KbFwLL-NH2 (b = β-(3-benzothienyl)-d-alanine) were synthesized by solid phase peptide synthesis in order to identify the influence of aromaticity, charge, and hydrophobicity. Potency and efficacy of the hexapeptides were evaluated in inositol triphosphate turnover assays. Notably, modifications directly at the C-terminal Leu(6) could influence peptide efficacy leading to decreased constitutive activity. High hydrophobicity at the C-terminal position was of importance for elevated inverse agonist activity, the introduction of charged amino acids led to decreased potency. In contrast, structure-activity relationship studies of Leu(5) located closer to the aromatic core revealed an agonism-inducing position. These findings imply that amino acids with possible cation-π or π-π interactions and a suitable orientation at the C-terminus of the aromatic core induce agonism. Receptor binding studies showed that most peptides bind to the receptor at a concentration of 1 µM and modification directly at the C-terminus is generally more accepted than Leu(5) substitution. Interestingly, this observation is not dependent on the type of modification. These studies reveal another switch region of the short ghrelin receptor ligand pointing out the sensitivity of the ghrelin receptor binding pocket. © 2015 Wiley Periodicals, Inc.

  6. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling.

    Directory of Open Access Journals (Sweden)

    Shailaja Kunda

    Full Text Available Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR. We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+. Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+. Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+ (iCa(2+ influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/- and GluN2B(-/- mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/--derived mouse neurons, as compared to those isolated from GluN2B(-/--mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133, suggesting that the peptides modulated iCa(2+ entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+ influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  7. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling.

    Science.gov (United States)

    Kunda, Shailaja; Cheriyan, John; Hur, Michael; Balsara, Rashna D; Castellino, Francis J

    2013-01-01

    Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con) Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR). We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+). Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+). Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+) (iCa(2+)) influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/-) and GluN2B(-/-) mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/-)-derived mouse neurons, as compared to those isolated from GluN2B(-/-)-mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133), suggesting that the peptides modulated iCa(2+) entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+) influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  8. The peptide hemopressin acts through CB1 cannabinoid receptors to reduce food intake in rats and mice.

    Science.gov (United States)

    Dodd, Garron T; Mancini, Giacomo; Lutz, Beat; Luckman, Simon M

    2010-05-26

    Hemopressin is a short, nine amino acid peptide (H-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His-OH) isolated from rat brain that behaves as an inverse agonist at the cannabinoid receptor CB(1), and is shown here to inhibit agonist-induced receptor internalization in a heterologous cell model. Since this peptide occurs naturally in the rodent brain, we determined its effect on appetite, an established central target of cannabinoid signaling. Hemopressin dose-dependently decreases night-time food intake in normal male rats and mice, as well as in obese ob/ob male mice, when administered centrally or systemically, without causing any obvious adverse side effects. The normal, behavioral satiety sequence is maintained in male mice fasted overnight, though refeeding is attenuated. The anorectic effect is absent in CB(1) receptor null mutant male mice, and hemopressin can block CB(1) agonist-induced hyperphagia in male rats, providing strong evidence for antagonism of the CB(1) receptor in vivo. We speculate that hemopressin may act as an endogenous functional antagonist at CB(1) receptors and modulate the activity of appetite pathways in the brain.

  9. Constitutively active form of natriuretic peptide receptor 2 ameliorates experimental pulmonary arterial hypertension.

    Science.gov (United States)

    Nawa, Nobutoshi; Ishida, Hidekazu; Katsuragi, Shinichi; Baden, Hiroki; Takahashi, Kunihiko; Higeno, Ryota; Torigoe, Fumiko; Mihara, Seiko; Narita, Jun; Miura, Kohji; Nakamura, Kazufumi; Kogaki, Shigetoyo; Ozono, Keiichi

    2016-01-01

    We recently found a constitutively active mutant of natriuretic peptide receptor 2 (caNPR2; V883M), which synthesizes larger amounts of cyclic guanosine monophosphate (cGMP) intracellularly without any ligand stimulation than existing drugs. The aim of this study was to investigate the therapeutic effects of gene transduction using caNPR2 for pulmonary arterial hypertension (PAH). In vitro gene transduction into human pulmonary arterial smooth muscle cells using Sendai virus (SeV) vectors carrying caNPR2 induced 10,000-fold increases in the synthesis of cGMP without ligand stimulation, and the proliferation of caNPR2-expressing cells was significantly attenuated. The PAH model rats generated by hypoxia and the administration of SU5416 were then treated with SeV vectors through a direct injection into the left pulmonary artery. Right ventricular systolic pressure was significantly decreased 2 weeks after the treatment, while systemic blood pressure remained unchanged. Histological analyses revealed that the medial wall thickness and occlusion rate of pulmonary arterioles were significantly improved in caNPR2-treated lungs. Neither the systemic integration of virus vectors nor side effects were observed. The massive stimulation of cGMP synthesis by gene therapy with caNPR2 was safe and effective in a PAH rat model and, thus, has potential as a novel therapy for patients with severe progressive PAH.

  10. Constitutively active form of natriuretic peptide receptor 2 ameliorates experimental pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    Nobutoshi Nawa

    2016-01-01

    Full Text Available We recently found a constitutively active mutant of natriuretic peptide receptor 2 (caNPR2; V883M, which synthesizes larger amounts of cyclic guanosine monophosphate (cGMP intracellularly without any ligand stimulation than existing drugs. The aim of this study was to investigate the therapeutic effects of gene transduction using caNPR2 for pulmonary arterial hypertension (PAH. In vitro gene transduction into human pulmonary arterial smooth muscle cells using Sendai virus (SeV vectors carrying caNPR2 induced 10,000-fold increases in the synthesis of cGMP without ligand stimulation, and the proliferation of caNPR2-expressing cells was significantly attenuated. The PAH model rats generated by hypoxia and the administration of SU5416 were then treated with SeV vectors through a direct injection into the left pulmonary artery. Right ventricular systolic pressure was significantly decreased 2 weeks after the treatment, while systemic blood pressure remained unchanged. Histological analyses revealed that the medial wall thickness and occlusion rate of pulmonary arterioles were significantly improved in caNPR2-treated lungs. Neither the systemic integration of virus vectors nor side effects were observed. The massive stimulation of cGMP synthesis by gene therapy with caNPR2 was safe and effective in a PAH rat model and, thus, has potential as a novel therapy for patients with severe progressive PAH.

  11. Solid-Phase Extraction of Pesticides by Using Bioinspired Peptide Receptors

    Directory of Open Access Journals (Sweden)

    Valentina Lanzone

    2015-01-01

    Full Text Available A virtual development of hexapeptide receptors bioinspired by the acetylcholinesterase enzyme active site is proposed. A semicombinatorial approach was applied to generate a virtual hexapeptides library with different affinity properties towards organophosphate and carbamate pesticides. The virtual screening process was addressed to obtain peptides able to separate pesticide subclasses in the experimental work. Three hexapeptides, two generated by molecular modeling and one having a scrambled sequence, were used as selective sorbent materials for pesticides in preanalytical solid-phase extraction (SPE method. Selective adsorption and cross-reactivity were tested directly on a mix of four pesticides (carbaryl, chlorpyrifos-ethyl, malathion, and thiabendazole having different structures and physico-chemical properties, at a total concentration of 120 ppb (each pesticide at concentration of 30 ppb. The results were compared to traditional sorbent material such as C-18 and strata-X. Data showed that only one of the hexapeptides virtually designed had significant differences in competitive absorption between aliphatic pesticide malathion, fungicide thiabendazole chosen as negative control, and aromatic pesticides. These results partially supported the simulated strategy.

  12. Intracellular formyl peptide receptor regulates naïve CD4 T cell migration.

    Science.gov (United States)

    Lee, Ha Young; Jeong, Yu Sun; Lee, Mingyu; Kweon, Hee-Seok; Huh, Yang Hoon; Park, Joon Seong; Hwang, Ji Eun; Kim, Kyuseok; Bae, Yoe-Sik

    2018-02-08

    We found that formyl peptide receptor (FPR) 1 and FPR3 were expressed intracellularly and/or the nucleus of naïve CD4 T cell. Activation of naïve CD4 T cells with synthetic intracellular agonists dTAT-WKYMVm and CTP-WKYMVm for FPR members stimulated CD4 T cell migration via pertussis toxin-sensitive manner. Knockdown of FPR1, but not knockdown of FPR3, blocked dTAT-WKYMVm-induced naïve CD4 T cell migration. Stimulation of naïve CD4 T cells with dTAT-WKYMVm elicited the activation of ERK, p38 MAPK, and Akt. Activation of CD4 T cells with anti-CD3 and anti-CD28 antibodies caused surface expression of FPR1 and FPR3, but not FPR2. CD4 T cells isolated from sepsis patients expressed the three members of FPR family on their cell surface. Taken together, our results suggest that intracellular FPR in naïve CD4 T cells and surface FPRs in activated CD4 T cells might regulate immune responses by regulating CD4 T cell activity. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Paralytic subileus as an adverse effect of amino acid-based nephroprotection in a patient undergoing peptide receptor radionuclide therapy.

    Science.gov (United States)

    Werner, Rudolf A; Brumberg, Joachim; Dierks, Alexander; Herrmann, Ken; Biko, Johannes; Buck, Andreas K; Lapa, Constantin

    2015-03-01

    Peptide receptor radionuclide therapy is routinely used for neuroendocrine tumors. To prevent radiopeptide retention at the proximal tubule of the kidney, positively charged amino are coinfused. However, hyperkalemia (>5.0 mmol/L) in more than three fourth of patients has been reported. In our case, the patient experienced acute hyperkalemia with blood values greater than 7.0 mmol/L with gastroparesis and subileus.

  14. Therapeutic Efficacy with Treatment-related Toxicities of {sup 177}Lu-labeled Bombesin Derivative for the Peptide Receptor Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae Cheong; Cho, Eun Ha; Lee, So Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The gastrin-releasing peptide receptor (GRPR) has been shown to be overexpressed in many human tumours, including breast cancer, prostate cancer, small cell lung cancer, ovarian cancers, endometrial cancers, and gastrointestinal stromal tumors. In particular, GRPR expression is high in 83 % of invasive primary prostatic carcinomas. These results suggest that {sup 177}Lu-labeled bombesin derivative has promising characteristics as a novel nuclear medicine, especially for the treatment of GRPR over-expressing prostate tumors.

  15. Peptide receptor radionuclide therapy with Y-DOTATOC and (177)Lu-DOTATOC in advanced neuroendocrine tumors: results from a Danish cohort treated in Switzerland

    DEFF Research Database (Denmark)

    Pfeifer, Andreas Klaus; Gregersen, Tine; Grønbæk, Henning

    2011-01-01

    Limited therapeutic options have highlighted the demand for new treatment modalities for patients with advanced neuroendocrine tumors (NET). Promising results of initial studies have warranted the implementation of peptide receptor radionuclide therapy (PRRT) in clinical practice. However, this t...

  16. Glucagon-Like Peptide-1 Receptor Activation Modulates Pancreatitis-Associated Gene Expression But Does Not Modify the Susceptibility to Experimental Pancreatitis in Mice

    National Research Council Canada - National Science Library

    Jacqueline A. Koehler; Laurie L. Baggio; Benjamin J. Lamont; Safina Ali; Daniel J. Drucker

    2009-01-01

    Glucagon-Like Peptide-1 Receptor Activation Modulates Pancreatitis-Associated Gene Expression But Does Not Modify the Susceptibility to Experimental Pancreatitis in Mice Jacqueline A. Koehler , Laurie L...

  17. In vivo stabilization of a gastrin-releasing peptide receptor antagonist enhances pet imaging and radionuclide therapy of prostate cancer in preclinical studies

    OpenAIRE

    Chatalic, Kristell; Konijnenberg, Mark; Nonnekens, Julie; de Blois, Erik; Hoeben, Sander; Ridder, Corrina; Brunel, Luc; Fehrentz, Jean-Alain; Martinez, Jean; Gent, Dik; Nock, Berthold; Maina, Theodosia; van Weerden, Wytske; de Jong, Marion

    2016-01-01

    textabstractA single tool for early detection, accurate staging, and personalized treatment of prostate cancer (PCa) would be a major breakthrough in the field of PCa. Gastrin-releasing peptide receptor (GRPR) targeting peptides are promising probes for a theranostic approach for PCa overexpressing GRPR. However, the successful application of small peptides in a theranostic approach is often hampered by their fast in vivo degradation by proteolytic enzymes, such as neutral endopeptidase (NEP)...

  18. An activating mutation in the kinase homology domain of the natriuretic peptide receptor-2 causes extremely tall stature without skeletal deformities

    NARCIS (Netherlands)

    S.E. Hannema (Sabine); H.A. van Duyvenvoorde (Hermine); P. Thomas (Premsler); R.-B. Yang (Ruey-Bing); T.D. Mueller (Thomas); I.J. Gassner (Ingrid); H. Oberwinkler (Heike); F. Roelfsema (Ferdinand); G.W.E. Santen (Gijs); T. Prickett (Timothy); S.G. Kant (Sarina); A. Verkerk; A.G. Uitterlinden (André); E. Espiner (Eric); C.A. Ruivenkamp (Claudia); W. Oostdijk (Wilma); A.M. Pereira (Alberto); M. Losekoot (Monique); M. Kuhn (Michael); J.M. Wit (Jan)

    2013-01-01

    textabstractBackground: C-type natriuretic peptide (CNP)/natriuretic peptide receptor 2 (NPR2) signaling is essential for long bone growth. Enhanced CNP production caused by chromosomal translocations results in tall stature, a Marfanoid phenotype, and skeletal abnormalities.Asimilar phenotype was

  19. In vivo stabilization of a gastrin-releasing peptide receptor antagonist enhances pet imaging and radionuclide therapy of prostate cancer in preclinical studies

    NARCIS (Netherlands)

    K.L.S. Chatalic (Kristell); M. Konijnenberg (Mark); J. Nonnekens (Julie); E. de Blois (Erik); S. Hoeben (Sander); C.M.A. Ridder (Corrina); L. Brunel (Luc); J.-A. Fehrentz (Jean-Alain); J. Martinez (Jean); D.C. van Gent (Dik); B.A. Nock (Berthold); T. Maina (Theodosia); W.M. van Weerden (Wytske); M. Jong (Marion de)

    2016-01-01

    textabstractA single tool for early detection, accurate staging, and personalized treatment of prostate cancer (PCa) would be a major breakthrough in the field of PCa. Gastrin-releasing peptide receptor (GRPR) targeting peptides are promising probes for a theranostic approach for PCa overexpressing

  20. Effects of glucagon-like peptide-1 receptor agonists on weight loss: systematic review and meta-analyses of randomised controlled trials

    DEFF Research Database (Denmark)

    Vilsbøll, Tina; Christensen, Mikkel; Junker, Anders E

    2012-01-01

    To determine whether treatment with agonists of glucagon-like peptide-1 receptor (GLP-1R) result in weight loss in overweight or obese patients with or without type 2 diabetes mellitus.......To determine whether treatment with agonists of glucagon-like peptide-1 receptor (GLP-1R) result in weight loss in overweight or obese patients with or without type 2 diabetes mellitus....

  1. Novel evolutionary lineages of the invertebrate oxytocin/vasopressin superfamily peptides and their receptors in the common octopus (Octopus vulgaris)

    Science.gov (United States)

    Kanda, Atsuhiro; Satake, Honoo; Kawada, Tsuyoshi; Minakata, Hiroyuki

    2004-01-01

    The common octopus, Octopus vulgaris, is the first invertebrate species that was shown to possess two oxytocin/vasopressin (OT/VP) superfamily peptides, octopressin (OP) and cephalotocin (CT). Previously, we cloned a GPCR (G-protein-coupled receptor) specific to CT [CTR1 (CT receptor 1)]. In the present study, we have identified an additional CTR, CTR2, and a novel OP receptor, OPR. Both CTR2 and OPR include domains and motifs typical of GPCRs, and the intron– exon structures are in accord with those of OT/VP receptor genes. CTR2 and OPR expressed in Xenopus oocytes induced calcium-mediated inward chloride current in a CT- and OP-specific manner respectively. Several regions and residues, which are requisite for binding of the vertebrate OT/VP receptor family with their ligands, are highly conserved in CTRs, but not in OPR. These different sequences between CTRs and OPR, as well as the amino acid residues of OP and CT at positions 2–5, were presumed to play crucial roles in the binding selectivity to their receptors, whereas the difference in the polarity of OT/VP family peptide residues at position 8 confers OT and VP with the binding specificity in vertebrates. CTR2 mRNA was present in various peripheral tissues, and OPR mRNA was detected in both the nervous system and peripheral tissues. Our findings suggest that the CT and OP genes, similar to the OT/VP family, evolved through duplication, but the ligand–receptor selectivity were established through different evolutionary lineages from those of their vertebrate counterparts. PMID:15504101

  2. Glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes

    OpenAIRE

    Lee, Seungah; Lee, Dong Yun

    2017-01-01

    The prevalence of type 2 diabetes (T2D) is increasing worldwide. Patients with T2D suffer from various diabetes-related complications. Since there are many patients with T2D that cannot be controlled by previously developed drugs, it has been necessary to develop new drugs, one of which is a glucagon-like peptide-1 (GLP-1) based therapy. GLP-1 has been shown to ameliorate diabetes-related conditions by augmenting pancreatic ?-cell insulin secretion and having the low risk of causing hypoglyce...

  3. Individual MHCI-Restricted T-Cell Receptors are Characterized by a Unique Peptide Recognition Signature.

    Science.gov (United States)

    Wooldridge, Linda

    2013-01-01

    Effective immunity requires that a limited TCR repertoire is able to recognize a vast number of foreign peptide-MHCI (peptide-major histocompatibility complex class I) molecules. This challenge is overcome by the ability of individual TCRs to recognize large numbers of peptides. Recently, it was demonstrated that MHCI-restricted TCRs can recognize up to 10(6) peptides of a defined length. Astonishingly, this remarkable level of promiscuity does not extend to peptides of different lengths, a fundamental observation that has broad implications for CD8(+) T-cell immunity. In particular, the findings suggest that effective immunity can only be achieved by mobilization of "length-matched" CD8(+) T-cell clonotypes. Overall, recent findings suggest that every TCR is specific for a unique set of peptides, which can be described as a unique "peptide recognition signature" (PRS) and consists of three components: (1) peptide length preference, (2) number of peptides recognized; and, (3) sequence identity (e.g., self versus pathogen derived). In future, the ability to de-convolute peptide recognition signatures across the normal and pathogenic repertoire will be essential for understanding the system requirements for effective CD8(+) T-cell immunity and elucidating mechanisms which underlie CD8(+) T-cell mediated disease.

  4. Individual MHCI-Restricted T-Cell Receptors are Characterized by a Unique Peptide Recognition Signature

    Science.gov (United States)

    Wooldridge, Linda

    2013-01-01

    Effective immunity requires that a limited TCR repertoire is able to recognize a vast number of foreign peptide-MHCI (peptide-major histocompatibility complex class I) molecules. This challenge is overcome by the ability of individual TCRs to recognize large numbers of peptides. Recently, it was demonstrated that MHCI-restricted TCRs can recognize up to 106 peptides of a defined length. Astonishingly, this remarkable level of promiscuity does not extend to peptides of different lengths, a fundamental observation that has broad implications for CD8+ T-cell immunity. In particular, the findings suggest that effective immunity can only be achieved by mobilization of “length-matched” CD8+ T-cell clonotypes. Overall, recent findings suggest that every TCR is specific for a unique set of peptides, which can be described as a unique “peptide recognition signature” (PRS) and consists of three components: (1) peptide length preference, (2) number of peptides recognized; and, (3) sequence identity (e.g., self versus pathogen derived). In future, the ability to de-convolute peptide recognition signatures across the normal and pathogenic repertoire will be essential for understanding the system requirements for effective CD8+ T-cell immunity and elucidating mechanisms which underlie CD8+ T-cell mediated disease. PMID:23888160

  5. An assessment tumor targeting ability of 177Lu labeled cyclic CCK analogue peptide by binding with cholecystokinin receptor

    Directory of Open Access Journals (Sweden)

    Eun-Ha Cho

    2016-07-01

    Full Text Available The cholecystokinin (CCK receptor is known as a receptor that is overexpressed in many human tumors. The present study was designed to investigate the targeting ability of cyclic CCK analogue in AR42J pancreatic cells. The CCK analogues, DOTA-K(glucose-Gly-Trp-Nle-Asp-Phe (DOTA-glucose-CCK and DOTA-Nle-cyclo(Glu-Trp-Nle-Asp-Phe-Lys-NH2 (DOTA-[Nle]-cCCK, were synthesized and radiolabeled with 177Lu, and competitive binding was evaluated. The binding appearance of synthesized peptide with AR42J cells was evaluated by confocal microscopy. And bio-distribution was performed in AR42J xenografted mice. Synthesized peptides were prepared by a solid phase synthesis method, and their purity was over 98%. DOTA is the chelating agent for 177Lu-labeling, in which the peptides were radiolabeled with 177Lu by a high radiolabeling yield. A competitive displacement of 125I-CCK8 on the AR42J cells revealed that the 50% inhibitory concentration value (IC50 was 12.3 nM of DOTA-glucose-CCK and 1.7 nM of DOTA-[Nle]-cCCK. Radio-labeled peptides were accumulated in AR42J tumor in vivo, and %ID/g of the tumor was 0.4 and 0.9 at 2 h p.i. It was concluded that 177Lu-DOTA-[Nle]-cCCK has higher binding affinity than 177Lu-DOTA-glucose-CCK and can be a potential candidate as a targeting modality for a CCK receptor over-expressing tumors.

  6. Functional characterization and expression analysis of the myoinhibiting peptide receptor in the Chagas disease vector, Rhodnius prolixus.

    Science.gov (United States)

    Paluzzi, Jean-Paul V; Haddad, Amir Saleem; Sedra, Laura; Orchard, Ian; Lange, Angela B

    2015-01-05

    Myoinhibiting peptides (MIPs), which are also known as B-type allatostatins, are a family of neuropeptides found in protostomes. Their primary structure is characterized by an amidated carboxyl-terminal motif consisting of a conserved pair of tryptophan residues normally separated by six non-conserved amino acids (W(X6)Wamide). In the fruit fly Drosophila melanogaster, MIPs are likely the ancestral ligands of the sex peptide receptor, which plays an important role in courtship and reproduction. Recently, several endogenous MIPs were discovered in the Chagas disease vector, Rhodnius prolixus, having both conserved (W(X6)Wamide) and atypical (W(X7)Wamide) carboxyl-terminal motifs. Physiological functions of MIPs are plentiful and include inhibition of visceral muscle activity; a role that has been illustrated on hindgut in R. prolixus. In order to identify novel physiological targets and elucidate biological actions for the MIPs in R. prolixus, we have isolated and examined the spatial expression profile of the MIP receptor transcript in various fifth instar tissues and have additionally determined the expression profile in reproductive tissues of fifth instar as well as adult insects. The most abundant MIP receptor transcript expression was found in the salivary glands and central nervous system, which corroborates roles previously determined for MIPs in other insects. We functionally-characterized the endogenous MIP receptor and examined its activation by R. prolixus MIPs containing the typical W(X6)Wamide and atypical W(X7)Wamide carboxyl-terminal motifs. These peptides dose-dependently activated the MIP receptor (RhoprMIPr1) with EC50 values in the mid-nanomolar range. We also examined the activity of these RhoprMIPs on spontaneous muscle contractions of oviducts from female adult R. prolixus. Our findings confirm the myoinhibitory nature of the MIP peptides, which dose-dependently reduced spontaneous oviduct contractions by nearly 70%, again having mid

  7. Gastro-Resistant Insulin Receptor-Binding Peptide from Momordica charantia Improved the Glucose Tolerance in Streptozotocin-Induced Diabetic Mice via Insulin Receptor Signaling Pathway.

    Science.gov (United States)

    Lo, Hsin-Yi; Li, Chia-Cheng; Chen, Feng-Yuan; Chen, Jaw-Chyun; Hsiang, Chien-Yun; Ho, Tin-Yun

    2017-10-25

    Momordica charantia is a commonly used food and has been used for the management of diabetes. Our previous study has identified an insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia. Here we identified the gastro-resistant hypoglycemic bioactive peptides from protease-digested mcIRBP. By in vitro digestion and IR kinase activity assay, we found that a 9-amino-acid-residue peptide, mcIRBP-9, was a gastro-resistant peptide that enhanced IR kinase activities. mcIRBP-9 activated IR signaling transduction pathway, which resulted in the phosphorylation of IR, the translocation of glucose transporter 4, and the uptake of glucose in cells. Intraperitoneal and oral administration of mcIRBP-9 stimulated the glucose clearance by 30.91 ± 0.39% and 32.09 ± 0.38%, respectively, in streptozotocin-induced diabetic mice. Moreover, a pilot study showed that daily ingestion of mcIRBP-9 for 30 days decreased the fasting blood glucose levels and glycated hemoglobin (HbA1c) levels by 23.62 ± 6.14% and 24.06 ± 1.53%, respectively. In conclusion, mcIRBP-9 is a unique gastro-resistant bioactive peptide generated after the digestion of mcIRBP. Furthermore, oral administration of mcIRBP-9 improves both the glucose tolerance and the HbA1c levels in diabetic mice via targeting IR signaling transduction pathway.

  8. PET SUV correlates with radionuclide uptake in peptide receptor therapy in meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Haenscheid, Heribert; Buck, Andreas K.; Samnick, Samuel; Kreissl, Michael [University Hospital Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Sweeney, Reinhart A.; Flentje, Michael [University Hospital Wuerzburg, Department of Radiation Oncology, Wuerzburg (Germany); Loehr, Mario [University Hospital Wuerzburg, Department of Neurosurgery, Wuerzburg (Germany); Verburg, Frederik A. [University Hospital Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany)

    2012-08-15

    To investigate whether the tumour uptake of radionuclide in peptide receptor radionuclide therapy (PRRT) of meningioma can be predicted by a PET scan with {sup 68}Ga-labelled somatostatin analogue. In this pilot trial, 11 meningioma patients with a PET scan indicating somatostatin receptor expression received PRRT with 7.4 GBq {sup 177}Lu-DOTATOC or {sup 177}Lu-DOTATATE, followed by external beam radiotherapy. A second PET scan was scheduled for 3 months after therapy. During PRRT, multiple whole-body scans and a SPECT/CT scan of the head and neck region were acquired and used to determine the kinetics and dose in the voxel with the highest radionuclide uptake within the tumour. Maximum voxel dose and retention of activity 1 h after administration in PRRT were compared to the maximum standardized uptake values (SUV{sub max}) in the meningiomas from the PET scans before and after therapy. The median SUV{sub max} in the meningiomas was 13.7 (range 4.3 to 68.7), and the maximum fractional radionuclide uptake in voxels of size 0.11 cm{sup 3} was a median of 23.4 x 10{sup -6} (range 0.4 x 10{sup -6} to 68.3 x 10{sup -6}). A strong correlation was observed between SUV{sub max} and the PRRT radionuclide tumour retention in the voxels with the highest uptake (Spearman's rank test, P < 0.01). Excluding one patient who showed large differences in biokinetics between PET and PRRT and another patient with incomplete data, linear regression analysis indicated significant correlations between SUV{sub max} and the therapeutic uptake (r = 0.95) and between SUV{sub max} and the maximum voxel dose from PRRT (r = 0.76). Observed absolute deviations from the values expected from regression were a median of 5.6 x 10{sup -6} (maximum 9.3 x 10{sup -6}) for the voxel fractional radionuclide uptake and 0.40 Gy per GBq (maximum 0.85 Gy per GBq) {sup 177}Lu for the voxel dose from PRRT. PET with {sup 68}Ga-labelled somatostatin analogues allows the pretherapeutic assessment of tumour

  9. 68Ga-DOTA-NOC PET and peptide receptor radionuclide therapy in management of bilateral ovarian metastases from gastrointestinal carcinoid.

    Science.gov (United States)

    Singla, Suhas; Gupta, Santosh; Reddy, Rama Mohan; Durgapal, Prashant; Bal, C S

    2012-12-01

    The management of neuroendocrine tumours is challenging when curative surgery is ruled out because of distant metastases. We report a case of gastrointestinal carcinoid with bilateral ovarian metastases in a 50-year-old female who received octreotide therapy followed by peptide receptor radionuclide therapy and surgery thereafter. Somatostatin receptor expression on neuroendocrine tumours has implications in diagnosis and therapy. (68)Ga-DOTA-NOC PET is a recent advancement in the field of somatostatin receptor imaging. The lesions which demonstrate tracer uptake on positron emission tomographic studies can be further planned for treatment with octreotide and (177)Lu-DOTA-TATE. The case in discussion responded well to non-invasive treatment options before proceeding to definitive surgical management.

  10. DNA damage in blood lymphocytes in patients after {sup 177}Lu peptide receptor radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Eberlein, Uta; Bluemel, Christina; Buck, Andreas Konrad; Werner, Rudolf Alexander; Lassmann, Michael [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Nowak, Carina; Scherthan, Harry [Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Munich (Germany)

    2015-10-15

    The aim of the study was to investigate DNA double strand break (DSB) formation and its correlation with the absorbed dose to the blood lymphocytes of patients undergoing their first peptide receptor radionuclide therapy (PRRT) with {sup 177}Lu-labelled DOTATATE/DOTATOC. The study group comprised 16 patients receiving their first PRRT. At least six peripheral blood samples were obtained before, and between 0.5 h and 48 h after radionuclide administration. From the time-activity curves of the blood and the whole body, residence times for blood self-irradiation and whole-body irradiation were determined. Peripheral blood lymphocytes were isolated, fixed with ethanol and subjected to immunofluorescence staining for colocalizing γ-H2AX/53BP1 DSB-marking foci. The average number of DSB foci per cell per patient sample was determined as a function of the absorbed dose to the blood and compared with an in vitro calibration curve established in our laboratory with {sup 131}I and {sup 177}Lu. The average number of radiation-induced foci (RIF) per cell increased over the first 5 h after radionuclide administration and decreased thereafter. A linear fit from 0 to 5 h as a function of the absorbed dose to the blood agreed with our in vitro calibration curve. At later time-points the number of RIF decreased, indicating progression of DNA repair. Measurements of RIF and the absorbed dose to the blood after systemic administration of {sup 177}Lu may be used to obtain data on the individual dose-response relationships in vivo. Individual patient data were characterized by a linear dose-dependent increase and an exponential decay function describing repair. (orig.)

  11. Chondroitin Sulfate is the Primary Receptor for a Peptide-Modified AAV That Targets Brain Vascular Endothelium In Vivo.

    Science.gov (United States)

    Geoghegan, James C; Keiser, Nicholas W; Okulist, Anna; Martins, Inês; Wilson, Matthew S; Davidson, Beverly L

    2014-10-14

    Recently, we described a peptide-modified AAV2 vector (AAV-GMN) containing a capsid-displayed peptide that directs in vivo brain vascular targeting and transduction when delivered intravenously. In this study, we sought to identify the receptor that mediates transduction by AAV-GMN. We found that AAV-GMN, but not AAV2, readily transduces the murine brain endothelial cell line bEnd.3, a result that mirrors previously observed in vivo transduction profiles of brain vasculature. Studies in vitro revealed that the glycosaminoglycan, chondroitin sulfate C, acts as the primary receptor for AAV-GMN. Unlike AAV2, chondroitin sulfate expression is required for cell transduction by AAV-GMN, and soluble chondroitin sulfate C can robustly inhibit AAV-GMN transduction of brain endothelial cells. Interestingly, AAV-GMN retains heparin-binding properties, though in contrast to AAV2, it poorly transduces cells that express heparan sulfate but not chondroitin sulfate, indicating that the peptide insertion negatively impacts heparan-mediated transduction. Lastly, when delivered directly, this modified virus can transduce multiple brain regions, indicating that the potential of AAV-GMN as a therapeutic gene delivery vector for central nervous system disorders is not restricted to brain vascular endothelium.

  12. Chondroitin Sulfate is the Primary Receptor for a Peptide-Modified AAV That Targets Brain Vascular Endothelium In Vivo

    Directory of Open Access Journals (Sweden)

    James C Geoghegan

    2014-01-01

    Full Text Available Recently, we described a peptide-modified AAV2 vector (AAV-GMN containing a capsid-displayed peptide that directs in vivo brain vascular targeting and transduction when delivered intravenously. In this study, we sought to identify the receptor that mediates transduction by AAV-GMN. We found that AAV-GMN, but not AAV2, readily transduces the murine brain endothelial cell line bEnd.3, a result that mirrors previously observed in vivo transduction profiles of brain vasculature. Studies in vitro revealed that the glycosaminoglycan, chondroitin sulfate C, acts as the primary receptor for AAV-GMN. Unlike AAV2, chondroitin sulfate expression is required for cell transduction by AAV-GMN, and soluble chondroitin sulfate C can robustly inhibit AAV-GMN transduction of brain endothelial cells. Interestingly, AAV-GMN retains heparin-binding properties, though in contrast to AAV2, it poorly transduces cells that express heparan sulfate but not chondroitin sulfate, indicating that the peptide insertion negatively impacts heparan-mediated transduction. Lastly, when delivered directly, this modified virus can transduce multiple brain regions, indicating that the potential of AAV-GMN as a therapeutic gene delivery vector for central nervous system disorders is not restricted to brain vascular endothelium.

  13. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D. J.; ten Kulve, J. S.; Groot, P. F. C.; Ruhe, H. G.; Barkhof, F.; Sloan, J. H.; Diamant, M.; Ijzerman, R. G.

    AimTo test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. MethodsAs part of a larger study, we determined the effects of GLP-1 receptor activation on brain

  14. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D.J.; ten Kulve, J.S.; Groot, P.F.C.; Ruhe, H.G.; Barkhof, F.; Sloan, J.H.; Diamant, M.; IJzerman, R.G.

    2015-01-01

    Aim: To test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. Methods: As part of a larger study, we determined the effects of GLP-1 receptor activation on brain

  15. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D. J.; ten Kulve, J. S.; Groot, P. F. C.; Ruhé, H. G.; Barkhof, F.; Sloan, J. H.; Diamant, M.; Ijzerman, R. G.

    2015-01-01

    To test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. As part of a larger study, we determined the effects of GLP-1 receptor activation on brain responses to

  16. Identification of novel peptide ligands for the cancer-specific receptor mutation EFGRvIII using a mixture-based synthetic combinatorial library

    DEFF Research Database (Denmark)

    Denholt, Charlotte Lund; Hansen, Paul Robert; Pedersen, Nina

    2009-01-01

    We report here, the design and synthesis of a positional scanning synthetic combinatorial library for the identification of novel peptide ligands targeted against the cancer-specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in se...

  17. Inhibition of discoidin domain receptor 2-mediated lung cancer cells progression by gold nanoparticle-aptamer-assisted delivery of peptides containing transmembrane-juxtamembrane 1/2 domain

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daehwan; Yeom, Ji-Hyun; Lee, Boeun; Lee, Kangseok [Department of Life Science, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Bae, Jeehyeon, E-mail: jeehyeon@cau.ac.kr [Department of Pharmacy, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Rhee, Sangmyung, E-mail: sangmyung.rhee@cau.ac.kr [Department of Life Science, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2015-08-21

    The delivery of biologically functional peptides into mammalian cells can be a direct and effective method for cancer therapy and treatment of other diseases. Discoidin domain receptor 2 (DDR2) is a collagen-induced receptor tyrosine kinase recently identified as a novel therapeutic target in lung cancer. In this study, we report that peptides containing the functional domain of DDR2 can be efficiently delivered into lung malignant cancer cells via a gold nanoparticle-DNA aptamer conjugate (AuNP-Apt)-based system. Peptide delivery resulted in the abrogation of DDR2 activation triggered by collagen. Moreover, the peptide delivered by the AuNP-Apt system inhibited cancer cell proliferation and invasion mediated by DDR2 activation. Thus, these results suggest that peptide loaded onto AuNP-Apt conjugates can be used for the development of peptide-based biomedical applications for the treatment of DDR2-positive cancer. - Highlights: • TM-JM1/2 peptides are efficiently delivered into cells by AuNP-Apt-conjugates. • TM-JM1/2 peptides loaded onto AuNP-Apt conjugates inhibit DDR2 activation. • Inhibition of DDR2 activation by TM-JM1/2 peptides decreases tumor progression.

  18. Prospects of Targeting the Gastrin Releasing Peptide Receptor and Somatostatin Receptor 2 for Nuclear Imaging and Therapy in Metastatic Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Simone U Dalm

    Full Text Available The gastrin releasing peptide receptor (GRPR and the somatostatin receptor 2 (SSTR2 are overexpressed on primary breast cancer (BC, making them ideal candidates for receptor-mediated nuclear imaging and therapy. The aim of this study was to determine whether these receptors are also suitable targets for metastatic BC.mRNA expression of human BC samples were studied by in vitro autoradiography and associated with radioligand binding. Next, GRPR and SSTR2 mRNA levels of 60 paired primary BCs and metastases from different sites were measured by quantitative reverse transcriptase polymerase chain reaction. Receptor mRNA expression levels were associated with clinico-pathological factors and expression levels of primary tumors and corresponding metastases were compared.Binding of GRPR and SSTR radioligands to tumor tissue correlated significantly with receptor mRNA expression. High GRPR and SSTR2 mRNA levels were associated with estrogen receptor (ESR1-positive tumors (p<0.001 for both receptors. There was no significant difference in GRPR mRNA expression of primary tumors versus paired metastases. Regarding SSTR2 mRNA expression, there was also no significant difference in the majority of cases, apart from liver and ovarian metastases which showed a significantly lower expression compared to the corresponding primary tumors (p = 0.02 and p = 0.03, respectively.Targeting the GRPR and SSTR2 for nuclear imaging and/or treatment has the potential to improve BC care in primary as well as metastatic disease.

  19. Calcitonin Gene-Related Peptide (Cgrp, Adrenomedullin (Am, Amylin, And Calcitonin (Ct Receptors And Overlapping Biological Actions

    Directory of Open Access Journals (Sweden)

    J.A. Fischer

    2001-01-01

    Full Text Available CGRP, AM, amylin, and CT have in common N-terminal 6-7 amino acid ring structures linked by disulfide bridges and amidated C-termini required for biological activity. For the related bioactive peptides, receptor-binding sites linked to cAMP stimulation and to a lesser extent to the phospholipase C signaling pathway have been identified in tissue specific manner. The highest density of CGRP receptors has been recognized in the cerebellum and the spinal cord. There photoaffinity-labeled N-glycosylated 60,000 and 54,000 Mr proteins are converted to 46,000 and 41,000 Mr components following endoglycosidase F/N-glycosidase F treatment. The same proteins were specifically labeled with [125I]-hCGRP-I(1-37 and -(8-37. Some cross-reaction between the CGRP receptor and AM was evident whereas amylin and CT were only recognized at over 10-7 M. A different AM receptor localized predominantly in the lung recognized CGRP at low, and amylin and calcitonin at equally high concentrations. CT receptor binding sites have been identified in osteoclasts and in the periventricular region of the brain. They cross-reacted with amylin at low concentrations and with CGRP and AM at over 10-7 M. Amylin receptor binding sites cross-reacting with salmon CT and CGRP but not with hCT and adrenomedullin to any great extent were originally described by Sexton in the nucleus accumbens and may represent a second CGRP receptor. The structure of a CT receptor was elucidated by the group of Goldring in 1991 through molecular cloning, and of a 60% homologous human CT receptor-like receptor (CRLR shortly thereafter here. The latter was an orphan receptor until the discovery of the receptor-activity-modifying proteins (RAMP by Foord which upon coexpression yield a CGRP receptor with RAMP1 and an AM receptor with RAMP2. Coexpression of the hCT receptor isotype 2 revealed a CGRP/amylin receptor with RAMP1 and an amylin receptor isotype with RAMP3. The CRLR/RAMP1 receptor antagonized by

  20. A peptide targeting an interaction interface disrupts the dopamine D1-D2 receptor heteromer to block signaling and function in vitro and in vivo: effective selective antagonism

    Science.gov (United States)

    Hasbi, Ahmed; Perreault, Melissa L.; Shen, Maurice Y. F.; Zhang, Lucia; To, Ryan; Fan, Theresa; Nguyen, Tuan; Ji, Xiaodong; O'Dowd, Brian F.; George, Susan R.

    2014-01-01

    Although the dopamine D1-D2 receptor heteromer has emerging physiological relevance and a postulated role in different neuropsychiatric disorders, such as drug addiction, depression, and schizophrenia, there is a need for pharmacological tools that selectively target such receptor complexes in order to analyze their biological and pathophysiological functions. Since no selective antagonists for the D1-D2 heteromer are available, serial deletions and point mutations were used to precisely identify the amino acids involved in an interaction interface between the receptors, residing within the carboxyl tail of the D1 receptor that interacted with the D2 receptor to form the D1-D2 receptor heteromer. It was determined that D1 receptor carboxyl tail residues 404Glu and 405Glu were critical in mediating the interaction with the D2 receptor. Isolated mutation of these residues in the D1 receptor resulted in the loss of agonist activation of the calcium signaling pathway mediated through the D1-D2 receptor heteromer. The physical interaction between the D1 and D2 receptor could be disrupted, as shown by coimmunoprecipitation and BRET analysis, by a small peptide generated from the D1 receptor sequence that contained these amino acids, leading to a switch in G-protein affinities and loss of calcium signaling, resulting in the inhibition of D1-D2 heteromer function. The use of the D1-D2 heteromer-disrupting peptide in vivo revealed a pathophysiological role for the D1-D2 heteromer in the modulation of behavioral despair. This peptide may represent a novel pharmacological tool with potential therapeutic benefits in depression treatment.—Hasbi, A., Perreault, M. L., Shen, M. Y. F., Zhang, L., To, R., Fan, T., Nguyen, T., Ji, X., O'Dowd, B. F., George, S. R. A peptide targeting an interaction interface disrupts the dopamine D1-D2 receptor heteromer to block signaling and function in vitro and in vivo: effective selective antagonism. PMID:25063849

  1. Anti-inflammatory properties of a novel peptide interleukin 1 receptor antagonist

    DEFF Research Database (Denmark)

    Klementiev, Boris; Li, Shizhong; Korshunova, Irina

    2014-01-01

    Interleukin 1 (IL-1) is implicated in neuroinflammation, an essential component of neurodegeneration. We evaluated the potential anti-inflammatory effect of a novel peptide antagonist of IL-1 signaling, Ilantide.......Interleukin 1 (IL-1) is implicated in neuroinflammation, an essential component of neurodegeneration. We evaluated the potential anti-inflammatory effect of a novel peptide antagonist of IL-1 signaling, Ilantide....

  2. A powerful cooperative interaction between a fusogenic peptide and lipofectamine for the enhancement of receptor-targeted, non-viral gene delivery via integrin receptors.

    Science.gov (United States)

    Zhang, X; Collins, L; Fabre, J W

    2001-01-01

    Following receptor-mediated endocytosis, vector/DNA complexes require assistance to exit endocytic vesicles in order to avoid degradation in the lysosomes. Overcoming this barrier is a major challenge for the development of receptor-targeted, non-viral gene delivery. The fusogenic peptide of influenza virus haemagglutinin, lipofectamine and chloroquine were tested singly and in combination in various doses for promoting in vitro gene transfer by an integrin-targeted, non-viral DNA vector (polylysine-molossin). The fusogenic peptide and lipofectamine both individually promoted integrin-targeted gene delivery. However, the combined use of these agents was particularly effective, even at concentrations where neither agent singly had any effect on promoting gene delivery by polylysine-molossin. This optimal combination was effective on several cell lines and primary cell cultures. On the HuH7 cell line, it was approximately five-fold more effective than optimal chloroquine concentrations for integrin-targeted gene delivery and four to five times more effective than commercially available polyethylenimine. With the beta-galactosidase reporter gene, 60-65% of HepG2 cells and 75-80% of HuH7 cells were positive. The surface charge of polylysine-molossin/DNA/lipofectamine/fusogenic peptide complexes was approximately the same as that of polylysine-molossin/DNA complexes. The size distribution of the complexes suggested that competitive binding of polylysine-molossin and lipofectamine to DNA influenced the overall efficacy of this approach. Although the mechanisms are not clear, the combined use of very low doses of two membrane-destabilizing agents results in high levels of receptor-targeted gene delivery.

  3. Tachykinins stimulate release of peptide hormones (glucagon-like peptide-1) and paracrine (somatostatin) and neurotransmitter (vasoactive intestinal polypeptide) from porcine ileum through NK-1 receptors.

    Science.gov (United States)

    Schmidt, P T; Rickelt, L F; Holst, J J

    1999-07-01

    The effects of infusion of the two tachykinins, substance P (SP) and neurokinin A (NKA), and of capsaicin on the release of glucagon-like peptide-1 (GLP-1), somatostatin, and vasoactive intestinal polypeptide (VIP) were studied in isolated, vascularly perfused ileal segments. SP (10(-8) M) stimulated GLP-1, somatostatin, and VIP release to 141.8+/-6.6% (N = 18), 230.3+/-38.7% (N = 21), and 359.7+/-60.5% (N = 22) of basal output, respectively. NKA (10(-8) M) only stimulated VIP release (to 181.2+/-16.7% of basal release, N = 22). The effects of SP and NKA were blocked by the NK-1 receptor antagonist CP96345 (10(-6) M). Infusion of atropine (10(-6) M) had no effect on the SP-induced GLP-1 release, but partly inhibited the effect of SP on somatostatin and VIP release, and the effect of NKA on VIP release. Capsaicin infusions (10(-5) M) significantly stimulated both GLP-1, somatostatin, and VIP release to 111.1+/-4.5% (N = 9), 138.0+/-15.8% (N = 9) and 208.3+/-63.8% (N = 8) of basal release, respectively. Simultaneous addition of receptor antagonists to all three tachykinin receptors (CP96345, SR48968, and SR142801, all at 10(-6) M) significantly inhibited the effect of capsaicin on VIP release, whereas the release of GLP-1 and somatostatin was unaffected. We conclude that tachykinins potently stimulate the release of GLP-1, somatostatin, and VIP in the porcine ileum via NK-1 receptors. The effect on somatostatin and VIP is partly mediated via cholinergic neurons. Sensory neurons releasing tachykinins could be involved in the regulation of VIPergic neurons.

  4. Intravenous peptide YY3-36 and Y2 receptor antagonism in the rat: effects on feeding behaviour.

    Science.gov (United States)

    Scott, V; Kimura, N; Stark, J A; Luckman, S M

    2005-07-01

    Systemic injection of peptide YY3-36 reduces food intake in rodents and humans, although some groups have reported a lack of response. PYY3-36 is thought to act via the Y2 receptor to presynaptically inhibit the release of neuropeptide Y and GABA from hypothalamic arcuate neurones. Due to the controversy surrounding its action in rodents, we tested the peptide intravenously on feeding behaviour in rats and attempted to block its actions with the Y2 receptor antagonist BIIE0246. PYY3-36 significantly decreased food intake during the first hour in male Sprague-Dawley rats fasted overnight and then re-fed. BIIE0246 had no effect alone on re-feeding, but completely blocked the action of PYY3-36. In a second experiment of similar design, the behavioural satiety sequence (BSS) was studied. Normal rats eat, drink, explore and groom before entering rest. PYY3-36 significantly reduced food eaten maintaining the normal BSS, although shifting it to the left as expected for a natural satiety factor. The latency to rest occurred earlier for animals given PYY3-36 alone and PYY3-36 tended to increase the total time in rest compared with controls. These behavioural effects of PYY3-36 were blocked by BIIE0246, and BIIE0246 alone did not have an effect on the BSS. These results support the role of PYY3-36 as a natural satiety factor acting through Y2 receptors.

  5. Morroniside, a secoiridoid glycoside from Cornus officinalis, attenuates neuropathic pain by activation of spinal glucagon-like peptide-1 receptors.

    Science.gov (United States)

    Xu, Meng; Wu, Hai-Yun; Liu, Hao; Gong, Nian; Wang, Yi-Rui; Wang, Yong-Xiang

    2017-04-01

    Iridoid glycosides containing the double bond scaffold of cyclopentapyran are reversible and orthosteric agonists of glucagon-like peptide-1 (GLP-1) receptors and exert anti-nociceptive and neuroprotective actions. Morroniside, derived from the medicinal herb Cornus officinalis, is an atypical secoiridoid containing a six-membered cyclic inner ether fragment. Here we investigated whether morroniside was an orthosteric GLP-1 receptor agonist and had anti-hypersensitivity activities in a model of neuropathic pain. We used a model of neuropathic pain, induced by tight ligation of L5/L6 spinal nerves in rats. Hydrogen peroxide-induced oxidative damage was also assayed in N9 microglial cells and human HEK293 cells stably expressing GLP-1 receptors. Morroniside protected against hydrogen peroxide-induced oxidative damage in N9 microglial and HEK293 cells that expressed mouse or human GLP-1 receptors, but not in HEK293T cells without GLP-1 receptors. The GLP-1 receptor orthosteric antagonist exendin(9-39) also concentration-dependently shifted the concentration-protective response curves of morroniside and exenatide to the right without affecting maximal protection, with similar pA2 values. Furthermore, morroniside given by oral gavage or intrathecally in neuropathic rats dose-dependently attenuated mechanical allodynia, with comparable Emax values and ED50 s of 335 mg·kg-1 and 7.1 μg and completely blocked thermal hyperalgesia. Daily intrathecal injections of morroniside over 7 days did not induce anti-allodynic tolerance. Pretreatment with intrathecal exendin(9-39) completely blocked systemic and intrathecal morroniside-induced mechanical anti-allodynia. Our data demonstrated that morroniside was an orthosteric agonist of GLP-1 receptors and produced antihypersensitivity in a neuropathic pain model by activation of spinal GLP-1 receptors. © 2017 The British Pharmacological Society.

  6. Agonism of free fatty acid receptors 1 and 4 generates peptide YY-mediated inhibitory responses in mouse colon.

    Science.gov (United States)

    Moodaley, Runisha; Smith, David M; Tough, Iain R; Schindler, Marcus; Cox, Helen M

    2017-12-01

    Free fatty acid receptors FFA1 and FFA4 are located on enteroendocrine L cells with the highest gastrointestinal (GI) expression in descending colon. Their activation causes the release of glucagon-like peptide 1 and peptide YY (PYY) from L cells. Additionally, FFA1 agonism releases insulin from pancreatic β cells. As these receptors are modulators of nutrient-stimulated glucose regulation, the aim of this study was to compare the pharmacology of commercially available agonists (TUG424, TUG891, GW9508) with proven selective agonists (JTT, TAK-875, AZ423, Metabolex-36) in mice. Mouse mucosa was mounted in Ussing chambers, voltage-clamped and the resultant short-circuit current (Isc ) was recorded continuously. Pretreatments included antagonists of FFA1, Y1  or Y2 receptors. Glucose sensitivity was investigated by mannitol replacement apically, and colonic and upper GI transit was assessed in vitro and in vivo. FFA1 and FFA4 agonism required glucose and reduced Isc in a PYY-Y1 receptor-dependent manner. The novel compounds were more potent than GW9508. The FFA1 antagonists (GW1100 and ANT825) blocked FFA1 activity only and revealed FFA1 tonic activity. The FFA4 agonist, Metabolex-36, slowed colonic transit in vitro but increased small intestinal transit in vivo. The selective FFA1 and FFA4 agonists were more potent at reducing Isc than GW9508, a dual FFA1 and FFA4 agonist. A paracrine epithelial mechanism involving PYY-stimulated Y1 receptors mediated their responses, which were glucose sensitive, potentially limiting hypoglycaemia. ANT825 revealed tonic activity and the possibility of endogenous FFA1 ligands causing PYY release. Finally, FFA4 agonism induced regional differences in transit. © 2017 The British Pharmacological Society.

  7. Insulin/glucose induces natriuretic peptide clearance receptor in human adipocytes: a metabolic link with the cardiac natriuretic pathway.

    Science.gov (United States)

    Bordicchia, M; Ceresiani, M; Pavani, M; Minardi, D; Polito, M; Wabitsch, M; Cannone, V; Burnett, J C; Dessì-Fulgheri, P; Sarzani, R

    2016-07-01

    Cardiac natriuretic peptides (NP) are involved in cardiorenal regulation and in lipolysis. The NP activity is largely dependent on the ratio between the signaling receptor NPRA and the clearance receptor NPRC. Lipolysis increases when NPRC is reduced by starving or very-low-calorie diet. On the contrary, insulin is an antilipolytic hormone that increases sodium retention, suggesting a possible functional link with NP. We examined the insulin-mediated regulation of NP receptors in differentiated human adipocytes and tested the association of NP receptor expression in visceral adipose tissue (VAT) with metabolic profiles of patients undergoing renal surgery. Differentiated human adipocytes from VAT and Simpson-Golabi-Behmel Syndrome (SGBS) adipocyte cell line were treated with insulin in the presence of high-glucose or low-glucose media to study NP receptors and insulin/glucose-regulated pathways. Fasting blood samples and VAT samples were taken from patients on the day of renal surgery. We observed a potent insulin-mediated and glucose-dependent upregulation of NPRC, through the phosphatidylinositol 3-kinase pathway, associated with lower lipolysis in differentiated adipocytes. No effect was observed on NPRA. Low-glucose medium, used to simulate in vivo starving conditions, hampered the insulin effect on NPRC through modulation of insulin/glucose-regulated pathways, allowing atrial natriuretic peptide to induce lipolysis and thermogenic genes. An expression ratio in favor of NPRC in adipose tissue was associated with higher fasting insulinemia, HOMA-IR, and atherogenic lipid levels. Insulin/glucose-dependent NPRC induction in adipocytes might be a key factor linking hyperinsulinemia, metabolic syndrome, and higher blood pressure by reducing NP effects on adipocytes. Copyright © 2016 the American Physiological Society.

  8. The relaxin family peptide receptors and their ligands: new developments and paradigms in the evolution from jawless fish to mammals.

    Science.gov (United States)

    Yegorov, Sergey; Bogerd, Jan; Good, Sara V

    2014-12-01

    Relaxin family peptide receptors (Rxfps) and their ligands, relaxin (Rln) and insulin-like (Insl) peptides, are broadly implicated in the regulation of reproductive and neuroendocrine processes in mammals. Most placental mammals harbour genes for four receptors, namely rxfp1, rxfp2, rxfp3 and rxfp4. The number and identity of rxfps in other vertebrates are immensely variable, which is probably attributable to intraspecific variation in reproductive and neuroendocrine regulation. Here, we highlight several interesting, but greatly overlooked, aspects of the rln/insl-rxfp evolutionary history: the ancient origin, recruitment of novel receptors, diverse roles of selection, differential retention and lineage-specific loss of genes over evolutionary time. The tremendous diversity of rln/insl and rxfp genes appears to have arisen from two divergent receptors and one ligand that were duplicated by whole genome duplications (WGD) in early vertebrate evolution, although several genes, notably relaxin in mammals, were also duplicated via small scale duplications. Duplication and loss of genes have varied across lineages: teleosts retained more WGD-derived genes, dominated by those thought to be involved in neuroendocrine regulation (rln3, insl5 and rxfp 3/4 genes), while eutherian mammals witnessed the diversification and rapid evolution of genes involved in reproduction (rln/insl3). Several genes that arose early in evolutionary history were lost in most mammals, but retained in teleosts and, to a lesser extent, in early diverging tetrapods. To elaborate on their evolutionary history, we provide updated phylogenies of the Rxfp1/2 and Rxfp3/4 receptors and their ligands, including new sequences from early diverging vertebrate taxa such as coelacanth, skate, spotted gar, and lamprey. We also summarize the recent progress made towards understanding the functional biology of Rxfps in non-mammalian taxa, providing a new conceptual framework for research on Rxfp signaling across

  9. Molecular modeling of interactions of the non-peptide antagonist YM087 with the human vasopressin V1a, V2 receptors and with oxytocin receptors.

    Science.gov (United States)

    Giełdoń, Artur; Kaźmierkiewicz, Rajmund; Ślusarz, Rafał; Ciarkowski, Jerzy

    2001-12-01

    The nonapeptide hormones arginine vasopressin (CYFQNCPRG-NH2, AVP) and oxytocin (CYIQNCPLG-NH2, OT), control many essential functions in mammals. Their main activities include the urine concentration (via stimulation of AVP V2 receptors, V2R, in the kidneys), blood pressure regulation (via stimulation of vascular V1a AVP receptors, V1aR), ACTH control (via stimulation of V1b receptors, V1bR, in the pituitary) and labor and lactation control (via stimulation of OT receptors, OTR, in the uterus and nipples, respectively). All four receptor subtypes belong to the GTP-binding (G) protein-coupled receptor (GPCR) family. This work consists of docking of YM087, a potent non-peptide V1aR and V2R - but not OTR - antagonist, into the receptor models based on relatively new theoretical templates of rhodopsin (RD) and opiate receptors, proposed by Mosberg et al. (Univ. of Michigan, Ann Arbor, USA). It is simultaneously demonstrated that this RD template satisfactorily compares with the first historical GPCR structure of bovine rhodopsin (Palczewski et al., 2000) and that homology-modeling of V2R, V1aR and OTR using opiate receptors as templates is rational, based on relatively high (20-60%) sequence homology among the set of 4 neurophyseal and 4 opiate receptors. YM087 was computer-docked to V1aR, V2R and OTR using the AutoDock (Olson et al., Scripps Research Institute, La Jolla, USA) and subsequently relaxed using restrained simulated annealing and molecular dynamics, as implemented in AMBER program (Kollman et al., University of California, San Francisco, USA). From about 80 diverse configurations, sampled for each of the three ligand/receptor systems, 3 best energy-relaxed complexes were selected for mutual comparisons. Similar docking modes were found for the YM087/V1aR and YM087/V2R complexes, diverse from those of the YM087/OTR complexes, in agreement with the molecular affinity data.

  10. Comparison of biological stability and metabolism of CCK2 receptor targeting peptides, a collaborative project under COST BM0607

    Energy Technology Data Exchange (ETDEWEB)

    Ocak, Meltem [Innsbruck Medical University, Clinical Department of Nuclear Medicine, Innsbruck (Austria); Istanbul University, Department of Pharmaceutical Technology, Pharmacy Faculty, Istanbul (Turkey); Helbok, Anna; Rangger, Christine; Decristoforo, Clemens [Innsbruck Medical University, Clinical Department of Nuclear Medicine, Innsbruck (Austria); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department for Nuclear Medicine, Ljubljana (Slovenia); Nock, Berthold A. [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Morelli, Giancarlo [University of Naples ' ' Federico II' ' and IBB-CN, Department of Biological Sciences, CIRPeB, Naples (Italy); Eek, Annemarie [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Institute of Cancer, Barts and the London Queen Mary' s School of Medicine and Dentistry, Centre for Molecular Oncology and Imaging, London (United Kingdom); Breeman, W.A.P. [Erasmus MC Rotterdam, Department of Nuclear Medicine, Rotterdam (Netherlands); Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research Institute of Pathology, Berne (Switzerland)

    2011-08-15

    Stability of radiolabelled cholecystokinin 2 (CCK2) receptor targeting peptides has been a major limitation in the use of such radiopharmaceuticals especially for targeted radionuclide therapy applications, e.g. for treatment of medullary thyroid carcinoma (MTC). The purpose of this study was to compare the in vitro stability of a series of peptides binding to the CCK2 receptor [selected as part of the COST Action on Targeted Radionuclide Therapy (BM0607)] and to identify major cleavage sites. Twelve different 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-minigastrin/CCK conjugates were provided within an European COST Action (BM0607) by different laboratories and radiolabelled with {sup 177}Lu. Their in vitro stabilities were tested in fresh human serum. Radiochemical yields (RCY) and intact radioligands for half-life calculations were determined by radio-HPLC. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis of metabolites was performed to identify cleavage products using conjugates labelled with excess stable {sup nat}Lu, incubated in serum at 37 C. Urine metabolite analysis after injection in normal mice was performed by radio-HPLC analysis. Variable stability in human serum was found for the different peptides with calculated half-lives between 4.5 {+-} 0.1 h and 198 {+-} 0.1 h (n = 2). In urine of normal mice only metabolised peptide fragments were detected even at short times after injection for all peptides. MALDI-TOF MS revealed a major cleavage site of all minigastrin derivatives between Asp and Phe-NH{sub 2} at the C-terminal end. Development of CCK2 receptor ligands especially for therapeutic purposes in patients with MTC or small cell lung cancer (SCLC) is still ongoing in different laboratories. This comparative study provided valuable insight into the importance of biological stability especially in the context of other results of this comparative

  11. Structure-Function Analyses of a Staphylococcus epidermidis Autoinducing Peptide Reveals Motifs Critical for AgrC-type Receptor Modulation.

    Science.gov (United States)

    Yang, Tian; Tal-Gan, Yftah; Paharik, Alexandra E; Horswill, Alexander R; Blackwell, Helen E

    2016-07-15

    Staphylococcus epidermidis is frequently implicated in human infections associated with indwelling medical devices due to its ubiquity in the skin flora and formation of robust biofilms. The accessory gene regulator (agr) quorum sensing (QS) system plays a prominent role in the establishment of biofilms and infection by this bacterium. Agr activation is mediated by the binding of a peptide signal (or autoinducing peptide, AIP) to its cognate AgrC receptor. Many questions remain about the role of QS in S. epidermidis infections, as well as in mixed-microbial populations on a host, and chemical modulators of its agr system could provide novel insights into this signaling network. The AIP ligand provides an initial scaffold for the development of such probes; however, the structure-activity relationships (SARs) for activation of S. epidermidis AgrC receptors by AIPs are largely unknown. Herein, we report the first SAR analyses of an S. epidermidis AIP by performing systematic alanine and d-amino acid scans of the S. epidermidis AIP-I. On the basis of these results, we designed and identified potent, pan-group inhibitors of the AgrC receptors in the three S. epidermidis agr groups, as well as a set of AIP-I analogs capable of selective AgrC inhibition in either specific S. epidermidis agr groups or in another common staphylococcal species, S. aureus. In addition, we uncovered a non-native peptide agonist of AgrC-I that can strongly inhibit S. epidermidis biofilm growth. Together, these synthetic analogs represent new and readily accessible probes for investigating the roles of QS in S. epidermidis colonization and infections.

  12. Metallothionein and a peptide modeled after metallothionein, EmtinB, induce neuronal differentiation and survival through binding to receptors of the low-density lipoprotein receptor family

    DEFF Research Database (Denmark)

    Ambjørn, Malene; Asmussen, Johanne W; Lindstam, Mats

    2007-01-01

    of cell death (Bim(S)). Finally, evidence is provided that MT and EmtinB activate extracellular signal-regulated kinase, protein kinase B, and cAMP response element binding protein. Altogether, these results strongly suggest that MT and EmtinB induce their neuronal effects through direct binding......Accumulating evidence suggests that metallothionein (MT)-I and -II promote neuronal survival and regeneration in vivo. The present study investigated the molecular mechanisms underlying the differentiation and survival-promoting effects of MT and a peptide modeled after MT, EmtinB. Both MT...... and EmtinB directly stimulated neurite outgrowth and promoted survival in vitro using primary cultures of cerebellar granule neurons. In addition, expression and surface localization of megalin, a known MT receptor, and the related lipoprotein receptor-related protein-1 (LRP) are demonstrated in cerebellar...

  13. Personalized {sup 177}Lu-octreotate peptide receptor radionuclide therapy of neuroendocrine tumours: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Del Prete, Michela; Buteau, Francois-Alexandre; Beauregard, Jean-Mathieu [Laval Univ., QC (Canada). Dept. of Radiology and Nuclear Medicine, and Cancer Research Center; CHU de Quebec - Laval Univ., QC (Canada). Dept. of Medical Imaging, and Oncology Branch of Research Center

    2017-08-15

    Peptide receptor radionuclide therapy (PRRT) with {sup 177}Lu-octreotate is commonly administered at empiric, fixed amounts of injected radioactivity (IA). This results in highly variable absorbed doses to critical organs and suboptimal treatment of most patients. The primary aims of this study were to design a personalized PRRT (P-PRRT) protocol based on dosimetry, and to perform a simulation of this protocol in a retrospective cohort of patients with neuroendocrine tumours, in order to assess the potential of P-PRRT to safely increase the absorbed dose to the tumour during a four-cycle induction course. Thirty-six patients underwent 122 fixed-IA {sup 177}Lu-octreotate PRRT cycles with quantitative SPECT/CT-based dosimetry. Twenty-two patients completed a four-cycle induction course (29.6 ± 2.4 GBq cumulative IA), with kidney, bone marrow and maximum tumour absorbed doses of 16.2 ± 5.5, 1.3 ± 0.8, and 114 ± 66 Gy, respectively. We simulated a P-PRRT regime in which the renal absorbed dose per IA was predicted by the body surface area and glomerular filtration rate for the first cycle, and by renal dosimetry of the previous cycle(s) for the following cycles. Personalized IA was adjusted at each cycle in order to reach the prescribed renal absorbed dose of 23 Gy over four cycles (with a 25-50% reduction when renal or bone marrow function was impaired). Simulated IA and absorbed doses were based on actual patient characteristics, laboratory values and absorbed doses per IA delivered at each cycle. In the P-PRRT regime, cumulative IA could have been increased to 43.7 ± 16.5 GBq over four induction cycles (10.9 ± 5.0 GBq per cycle), yielding cumulative kidney, bone marrow and maximum tumour absorbed doses of 21.5 ± 2.5, 1.63 ± 0.61, and 163.4 ± 85.9 Gy, respectively. This resulted in an average 1.48-fold increase in cumulative maximum tumour absorbed dose over empiric PRRT (range, 0.68-2.64-fold; P = 0.0013). By standardizing the renal absorbed dose delivered

  14. Glucagon-like peptide-1 receptor agonists: a systematic review of comparative effectiveness research

    Directory of Open Access Journals (Sweden)

    Levin PA

    2017-04-01

    Full Text Available Philip A Levin,1 Hiep Nguyen,2 Eric T Wittbrodt,2 Seoyoung C Kim3 1Bay West Endocrinology Associates, Baltimore, MD, 2Health Economics and Outcomes Research, AstraZeneca, Wilmington, DE, 3Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA Background: Glucagon-like peptide-1 receptor agonists (GLP-1RAs act by increasing insulin secretion, decreasing glucagon secretion, slowing gastric emptying, and increasing satiety.Objective: Published evidence directly comparing GLP-1RAs with other approved treatments for type 2 diabetes (T2D was systematically reviewed.Methods: A literature search was performed using MEDLINE and Embase databases to identify papers comparing GLP-1RAs with other classes of glucose-lowering therapy in patients with T2D.Results: Of the 1303 papers identified, 57 met the prespecified criteria for a high-quality clinical trial or retrospective study. The efficacy and tolerability of approved GLP-1RAs (exenatide twice daily or once weekly, dulaglutide, liraglutide, lixisenatide, and albiglutide were compared with insulin products (23 prospective studies + seven retrospective studies, dipeptidyl peptidase-4 inhibitors (11 prospective studies + three retrospective studies, sulfonylureas (nine prospective studies + one retrospective study, thiazolidinediones (five prospective studies, and metformin (two prospective studies. GLP-1RAs are effective as a second-line therapy in improving glycemic parameters in patients with T2D. Reductions in glycated hemoglobin from baseline with GLP-1RAs tended to be greater or similar compared with insulin therapy. GLP-1RAs were consistently more effective in reducing body weight than most oral glucose-lowering drugs and insulin and were associated with lower hypoglycemia risk versus insulin or sulfonylureas. GLP-1RAs improved cardiovascular risk factors, and preliminary data suggest they improve

  15. Three-dimensional radiobiological dosimetry of kidneys for treatment planning in peptide receptor radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Sebastien; Hobbs, Robert F.; Boubaker, Ariane; Buchegger, Franz; He Bin; Frey, Eric C.; Sgouros, George [Institute of Radiation Physics, Lausanne University Hospital, 1007 Lausanne (Switzerland); Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231 (United States); Department of Nuclear Medicine, Lausanne University Hospital, 1011 Lausanne (Switzerland); Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231 (United States)

    2012-10-15

    Purpose: Peptide receptor radionuclide therapy (PRRT) delivers high absorbed doses to kidneys and may lead to permanent nephropathy. Reliable dosimetry of kidneys is thus critical for safe and effective PRRT. The aim of this work was to assess the feasibility of planning PRRT based on 3D radiobiological dosimetry (3D-RD) in order to optimize both the amount of activity to administer and the fractionation scheme, while limiting the absorbed dose and the biological effective dose (BED) to the renal cortex. Methods: Planar and SPECT data were available for a patient examined with {sup 111}In-DTPA-octreotide at 0.5 (planar only), 4, 24, and 48 h post-injection. Absorbed dose and BED distributions were calculated for common therapeutic radionuclides, i.e., {sup 111}In, {sup 90}Y and {sup 177}Lu, using the 3D-RD methodology. Dose-volume histograms were computed and mean absorbed doses to kidneys, renal cortices, and medullae were compared with results obtained using the MIRD schema (S-values) with the multiregion kidney dosimetry model. Two different treatment planning approaches based on (1) the fixed absorbed dose to the cortex and (2) the fixed BED to the cortex were then considered to optimize the activity to administer by varying the number of fractions. Results: Mean absorbed doses calculated with 3D-RD were in good agreement with those obtained with S-value-based SPECT dosimetry for {sup 90}Y and {sup 177}Lu. Nevertheless, for {sup 111}In, differences of 14% and 22% were found for the whole kidneys and the cortex, respectively. Moreover, the authors found that planar-based dosimetry systematically underestimates the absorbed dose in comparison with SPECT-based methods, up to 32%. Regarding the 3D-RD-based treatment planning using a fixed BED constraint to the renal cortex, the optimal number of fractions was found to be 3 or 4, depending on the radionuclide administered and the value of the fixed BED. Cumulative activities obtained using the proposed simulated

  16. GLP-2 receptor localizes to enteric neurons and endocrine cells expressing vasoactive peptides and mediates increased blood flow

    DEFF Research Database (Denmark)

    Guan, Xinfu; Karpen, Heidi E; Stephens, John

    2006-01-01

    BACKGROUND & AIMS: Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive hormone that exerts diverse actions in the gastrointestinal tract, including enhancing epithelial cell survival and proliferation, mucosal blood flow, and nutrient uptake and suppressing gastric motility and secretion....... These actions are mediated by the G-protein-coupled receptor, GLP-2R. Cellular localization of the GLP-2R and the nature of its signaling network in the gut, however, are poorly defined. Thus, our aim was to establish cellular localization of GLP-2R and functional connection to vascular action of GLP-2...

  17. Kunitz-Type Peptide HCRG21 from the Sea Anemone Heteractis crispa Is a Full Antagonist of the TRPV1 Receptor

    Directory of Open Access Journals (Sweden)

    Margarita Monastyrnaya

    2016-12-01

    Full Text Available Sea anemone venoms comprise multifarious peptides modulating biological targets such as ion channels or receptors. The sequence of a new Kunitz-type peptide, HCRG21, belonging to the Heteractis crispa RG (HCRG peptide subfamily was deduced on the basis of the gene sequence obtained from the Heteractis crispa cDNA. HCRG21 shares high structural homology with Kunitz-type peptides APHC1–APHC3 from H. crispa, and clusters with the peptides from so named “analgesic cluster” of the HCGS peptide subfamily but forms a separate branch on the NJ-phylogenetic tree. Three unique point substitutions at the N-terminus of the molecule, Arg1, Gly2, and Ser5, distinguish HCRG21 from other peptides of this cluster. The trypsin inhibitory activity of recombinant HCRG21 (rHCRG21 was comparable with the activity of peptides from the same cluster. Inhibition constants for trypsin and α-chymotrypsin were 1.0 × 10−7 and 7.0 × 10−7 M, respectively. Electrophysiological experiments revealed that rHCRG21 inhibits 95% of the capsaicin-induced current through transient receptor potential family member vanilloid 1 (TRPV1 and has a half-maximal inhibitory concentration of 6.9 ± 0.4 μM. Moreover, rHCRG21 is the first full peptide TRPV1 inhibitor, although displaying lower affinity for its receptor in comparison with other known ligands. Macromolecular docking and full atom Molecular Dynamics (MD simulations of the rHCRG21–TRPV1 complex allow hypothesizing the existence of two feasible, intra- and extracellular, molecular mechanisms of blocking. These data provide valuable insights in the structural and functional relationships and pharmacological potential of bifunctional Kunitz-type peptides.

  18. Kunitz-Type Peptide HCRG21 from the Sea Anemone Heteractis crispa Is a Full Antagonist of the TRPV1 Receptor.

    Science.gov (United States)

    Monastyrnaya, Margarita; Peigneur, Steve; Zelepuga, Elena; Sintsova, Oksana; Gladkikh, Irina; Leychenko, Elena; Isaeva, Marina; Tytgat, Jan; Kozlovskaya, Emma

    2016-12-15

    Sea anemone venoms comprise multifarious peptides modulating biological targets such as ion channels or receptors. The sequence of a new Kunitz-type peptide, HCRG21, belonging to the Heteractis crispa RG (HCRG) peptide subfamily was deduced on the basis of the gene sequence obtained from the Heteractis crispa cDNA. HCRG21 shares high structural homology with Kunitz-type peptides APHC1-APHC3 from H. crispa, and clusters with the peptides from so named "analgesic cluster" of the HCGS peptide subfamily but forms a separate branch on the NJ-phylogenetic tree. Three unique point substitutions at the N-terminus of the molecule, Arg1, Gly2, and Ser5, distinguish HCRG21 from other peptides of this cluster. The trypsin inhibitory activity of recombinant HCRG21 (rHCRG21) was comparable with the activity of peptides from the same cluster. Inhibition constants for trypsin and α-chymotrypsin were 1.0 × 10-7 and 7.0 × 10-7 M, respectively. Electrophysiological experiments revealed that rHCRG21 inhibits 95% of the capsaicin-induced current through transient receptor potential family member vanilloid 1 (TRPV1) and has a half-maximal inhibitory concentration of 6.9 ± 0.4 μM. Moreover, rHCRG21 is the first full peptide TRPV1 inhibitor, although displaying lower affinity for its receptor in comparison with other known ligands. Macromolecular docking and full atom Molecular Dynamics (MD) simulations of the rHCRG21-TRPV1 complex allow hypothesizing the existence of two feasible, intra- and extracellular, molecular mechanisms of blocking. These data provide valuable insights in the structural and functional relationships and pharmacological potential of bifunctional Kunitz-type peptides.

  19. Roles of μ-Opioid Receptors and Nociceptin/Orphanin FQ Peptide Receptors in Buprenorphine-Induced Physiological Responses in Primates

    Science.gov (United States)

    Cremeans, Colette M.; Gruley, Erin; Kyle, Donald J.

    2012-01-01

    Buprenorphine is known as a μ-opioid peptide (MOP) receptor agonist, but its antinociception is compromised by the activation of nociceptin/orphanin FQ peptide (NOP) receptors in rodents. The aim of this study was to investigate the roles of MOP and NOP receptors in regulating buprenorphine-induced physiological responses in primates (rhesus monkeys). The effects of MOP antagonist (naltrexone), NOP antagonist [(±)-1-[(3R*,4R*)-1-(cyclooctylmethyl)-3-(hydroxymethyl)-4-piperidinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one (J-113397)], and NOP agonists [(1S,3aS)-8-(2,3,3a,4,5,6-hexahydro-1H-phenalen-1-yl)-1-phenyl-1,3,8-triaza-spiro[4.5] decan-4-one (Ro 64-6198) and 3-endo-8-[bis(2-methylphenyl)methyl]-3-phenyl-8-azabicyclo[3.2.1]octan-3-ol (SCH 221510)] on buprenorphine were studied in three functional assays for measuring analgesia, respiratory depression, and itch in primates. Over the dose range of 0.01 to 0.1 mg/kg, buprenorphine dose-dependently produced antinociception, respiratory depression, and itch/scratching responses, and there was a ceiling effect at higher doses (0.1–1 mg/kg). Naltrexone (0.03 mg/kg) produced similar degrees of rightward shifts of buprenorphine's dose-response curves for all three endpoints. Mean pKB values of naltrexone (8.1–8.3) confirmed that MOP receptors mediated mainly buprenorphine-induced antinociception, respiratory depression, and itch/scratching. In contrast, J-113397 (0.1 mg/kg) did not change buprenorphine-induced physiological responses, indicating that there were no functional NOP receptors in buprenorphine-induced effects. More importantly, both NOP agonists, Ro 64-6198 and SCH 221510, enhanced buprenorphine-induced antinociception without respiratory depression and itch/ scratching. The dose-addition analysis revealed that buprenorphine in combination with the NOP agonist synergistically produced antinociceptive effects. These findings provided functional evidence that the activation of NOP receptors did not

  20. The glucagon-like peptide 2 receptor is expressed in enteric neurons and not in the epithelium of the intestine

    DEFF Research Database (Denmark)

    Pedersen, Jens; B. Pedersen, Nis; Brix, Sophie W.

    2015-01-01

    alone, (2) mucosa with lamina propria and epithelium, (3) the external muscle coat including myenteric plexus, (4) a compartment enriched for the myenteric plexus and (5) intestine without epithelium. Expression of Glp2r; chromogranin A; tubulin, beta 3; actin, gamma 2, smooth muscle, enteric and glial......Glucagon-like peptide 2 (GLP-2) is a potent intestinotrophic growth factor with therapeutic potential in the treatment of intestinal deficiencies. It has recently been approved for the treatment of short bowel syndrome. The effects of GLP-2 are mediated by specific binding of the hormone to the GLP......-2 receptor (GLP-2R) which was cloned in 1999. However, consensus about the exact receptor localization in the intestine has never been established. By physical, chemical and enzymatic tissue fragmentation, we were able to divide rat jejunum into different compartments consisting of: (1) epithelium...

  1. Calcitonin gene-related peptide and its receptor components in the human sphenopalatine ganglion -- interaction with the sensory system

    DEFF Research Database (Denmark)

    Csati, Anett; Tajti, Janos; Tuka, Bernadett

    2012-01-01

    , but not in neurons. RAMP1 immunoreactivity was localized in many neurons and SGCs. Thus, the two CGRP receptor components together were found in the SGCs. In addition, Western blot revealed the presence of RAMP1 and CLR in rat SPG. Our results suggest a possible sensory influence in the parasympathetic cranial......Clinical studies have suggested a link between the sensory trigeminal system and the parasympathetic ganglia. Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide which plays an important role in vasodilatation and pain transmission in craniocervical structures. The present study...... was designed to examine if CGRP and CGRP receptor components are present in the human sphenopalatine ganglion (SPG) in order to reveal an interaction between the sensory and parasympathetic systems. Indirect immunofluorescence technique was used for immunohistochemical demonstration of CGRP, the calcitonin...

  2. Modulation of natriuretic peptide receptors in human adipose tissue: molecular mechanisms behind the "natriuretic handicap" in morbidly obese patients.

    Science.gov (United States)

    Gentili, Alessandra; Frangione, Maria Rosaria; Albini, Elisa; Vacca, Carmine; Ricci, Maria Anastasia; De Vuono, Stefano; Boni, Marcello; Rondelli, Fabio; Rotelli, Luciana; Lupattelli, Graziana; Orabona, Ciriana

    2017-08-01

    The B-type natriuretic peptide (BNP) hormone plays a crucial role in the regulation of cardiovascular and energy homeostasis. Obesity is associated with low circulating levels of BNP, a condition known as "natriuretic handicap." Recent evidences suggest an altered expression of BNP receptors-both the signaling natriuretic peptide receptors (NPR)-A and the clearance NPR-C receptor-in adipose tissue (AT) as one of the putative causes of natriuretic handicap. The current study aims at clarifying the molecular mechanisms behind the natriuretic handicap, focusing on NPR modulation in the AT of obese and control subjects. The study enrolled 34 obese and 20 control subjects undergoing bariatric or abdominal surgery, respectively. The main clinical and biochemical parameters, including circulating BNP, were assessed. In visceral (VAT) and subcutaneous AT (SAT) samples, collected during surgery, the adipocytes and stromal vascular fraction (SVF) expression of NPR-A and NPR-C and the SVF secretion of interleukin 6 (IL-6) were determined. Both VAT and SAT from obese patients expressed a lower NPR-A/NPR-C ratio in adipocytes and the SVF secreted a higher level of IL-6, compared with the controls. Moreover, NPR-A/NPR-C ratio expressed by VAT and SAT adipocytes negatively correlated with body mass index, insulin, the Homeostasis Model Assessment of Insulin resistance, and IL-6 secreted by SVF, and the expression of the clearance receptor NPR-C, in both the VAT and SAT adipocytes, showed a negative correlation with circulating BNP. Overall, insulin resistance/hyperinsulinemia and AT inflammation (ie, high level of IL-6) are the major determinants of the lower NPR-A/NPR-C ratio in adipocytes, thus contributing to the natriuretic handicap in obese subjects. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Peptides derived from the solvent-exposed loops 3 and 4 of BDNF bind TrkB and p75(NTR) receptors and stimulate neurite outgrowth and survival

    DEFF Research Database (Denmark)

    Fobian, Kristina; Owczarek, Sylwia; Budtz, Christian

    2010-01-01

    to produce more specific compounds without side effects, small peptides mimicking protein function have been developed. The present study characterized two mimetic peptides, Betrofin 3 and Betrofin 4, derived from the BDNF sequence. Both Betrofins bound the cognate BDNF receptors, TrkB and p75(NTR......), and induced neurite outgrowth and enhanced neuronal survival, probably by inducing signaling through tha Akt and MAPK pathways. Distinct, charged residues within the Betrofin sequences were identified as important for generating the neuritogenic response, which was also inhibited when BDNF was added together...... with either Betrofin, indicating partial agonistic effects of the peptides. Thus, two peptides derived from BDNF induced neurite outgrowth and enhanced neuronal survival, probably through binding to BDNF receptors....

  4. Functional Consequences of Glucagon-like Peptide-1 Receptor Cross-talk and Trafficking

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Nøhr, Anne Cathrine; Wismann, Pernille

    2015-01-01

    The signaling capacity of seven-transmembrane/G-protein-coupled receptors (7TM/GPCRs) can be regulated through ligand-mediated receptor trafficking. Classically, the recycling of internalized receptors is associated with resensitization, whereas receptor degradation terminates signaling. We have......) and glucagon (GCGR) receptors. The interaction and cross-talk between coexpressed receptors is a wide phenomenon of the 7TM/GPCR superfamily. Numerous reports show functional consequences for signaling and trafficking of the involved receptors. On the basis of the high structural similarity and tissue...... coexpression, we here investigated the potential cross-talk between GLP-1R and GIPR or GCGR in both trafficking and signaling pathways. Using a real-time time-resolved FRET-based internalization assay, we show that GLP-1R, GIPR, and GCGR internalize with differential properties. Remarkably, upon coexpression...

  5. Early modulation by the dopamine D4 receptor of morphine-induced changes in the opioid peptide systems in the rat caudate putamen.

    Science.gov (United States)

    Gago, Belén; Fuxe, Kjell; Brené, Stefan; Díaz-Cabiale, Zaida; Reina-Sánchez, María Dolores; Suárez-Boomgaard, Diana; Roales-Buján, Ruth; Valderrama-Carvajal, Alejandra; de la Calle, Adelaida; Rivera, Alicia

    2013-12-01

    The peptides dynorphin and enkephalin modulate many physiological processes, such as motor activity and the control of mood and motivation. Their expression in the caudate putamen (CPu) is regulated by dopamine and opioid receptors. The current work was designed to explore the early effects of the acute activation of D4 and/or μ opioid receptors by the agonists PD168,077 and morphine, respectively, on the regulation of the expression of these opioid peptides in the rat CPu, on transcription factors linked to them, and on the expression of μ opioid receptors. In situ hybridization experiments showed that acute treatment with morphine (10 mg/kg) decreased both enkephalin and dynorphin mRNA levels in the CPu after 30 min, but PD168,077 (1 mg/kg) did not modify their expression. Coadministration of the two agonists demonstrated that PD168,077 counteracted the morphine-induced changes and even increased enkephalin mRNA levels. The immunohistochemistry studies showed that morphine administration also increased striatal μ opioid receptor immunoreactivity but reduced P-CREB expression, effects that were blocked by the PD168,077-induced activation of D4 receptors. The current results present evidence of functional D4 -μ opioid receptor interactions, with consequences for the opioid peptide mRNA levels in the rat CPu, contributing to the integration of DA and opioid peptide signaling. Copyright © 2013 Wiley Periodicals, Inc.

  6. [Relaxin-3 and relaxin family peptide receptors--from structure to functions of a newly discovered mammalian brain system].

    Science.gov (United States)

    Kania, Alan; Lewandowski, Marian H; Błasiak, Anna

    2014-01-01

    Relaxin-3, a member of the relaxin peptide family, was discovered in 2001 as a homologue of relaxin--a well-known reproductive hormone. However, it is the brain which turned out to be a major expression site of this newly discovered peptide. Both its molecular structure and expression pattern were shown to be very conserved among vertebrates. Extensive research carried out since the discovery of relaxin-3 contributed to the significant progress in our knowledge regarding this neuropeptide. The endogenous relaxin-3 receptor (RXFP3) was identified and the anatomy of the yet uncharacterized mammalian brain system was described, with nucleus incertus as the main center of relaxin-3 expression. Not only its diffusive projections throughout the whole brain, which reach various brain structures such as the hippocampus, septum, intergeniculate leaflet or amygdala, but also functional studies of the relaxin-3/RXFP3 signaling system, allowed this brain network to be classified as one of the ascending nonspecific brain systems. Thus far, research depicts the connection of relaxin-3 with phenomena such as feeding behavior, spatial memory, sleep/wake cycle or modulation of pituitary gland hormone secretion. Responsiveness of relaxin-3 neurons to stress factors and the strong orexigenic effect exerted by this peptide suggest its participation in modulation of feeding by stress, in particular of the chronic type. The discovery of relaxin-3 opened a new research field which will contribute to our better understanding of the neurobiological basis of feeding disorders.

  7. Synthesis and evaluation of a technetium-99m labeled cytotoxic bombesin peptide conjugate for targeting bombesin receptor-expressing tumors

    Energy Technology Data Exchange (ETDEWEB)

    Okarvi, Subhani M. [Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, MBC-03, PO Box 3354, Riyadh 11211 (Saudi Arabia)], E-mail: sokarvi@kfshrc.edu.sa; Al Jammaz, Ibrahim [Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, MBC-03, PO Box 3354, Riyadh 11211 (Saudi Arabia)

    2010-04-15

    Conjugation of the cytotoxic drugs to receptor-binding peptides is an attractive approach for the targeted delivery of cytotoxic peptide conjugates to tumor cells. In an attempt to develop an efficient peptide-based radiopharmaceutical for targeting bombesin (BN) receptor-expressing tumors (i.e., breast and prostate), we have prepared by solid-phase peptide synthesis, a novel BN analog derived from the universal sequence of BN and conjugated to a widely characterized antineoplastic agent, methotrexate (MTX). MTX-BN, after radiolabeling with {sup 99m}Tc via stannous-tartrate exchange, showed a good stability against cysteine and histidine transchelation as well as a high in vitro metabolic stability in human plasma. In vitro cell-binding and internalization on MDA-MB-231, MCF-7, T47-D breast cancer and PC-3 prostate cancer cell lines demonstrated high affinity and specificity of {sup 99m}Tc-MTX-BN towards both human breast and prostate cancer cells (binding affinities in nanomolar range). In addition, the radioconjugate displayed a significant internalization (values ranged between 19-35%) into the tumor cells. In vivo biodistribution and clearance kinetics in Balb/c mice are characterized by an efficient clearance from the blood and excretion mainly through the renal-urinary pathway with some elimination via the hepatobiliary system. In vivo tumor uptake in nude mice bearing MDA-MB-231 cells was 2.70{+-}0.44% ID/g at 1 h, whereas in nude mice with human epidermoid KB cells the accumulation in the tumor was found to be 1.48{+-}0.31% ID/g at 1 h post injection. The tumor uptake was always higher than in the blood and muscle, with good tumor retention and good tumor-to-blood and tumor-to-muscle ratios. The accumulation/retention in the major organs (i.e., lungs, stomach, liver, intestines, etc.) was low to moderate (<6% ID/g) in both healthy and tumor-bearing mice. However, the uptake/retention in the kidneys was rather high (up to 11.05{+-}1.80% ID/g), which is of a

  8. Parathyroid hormone-related protein (pthrp) is a gravisensor for lung and bone.

    Science.gov (United States)

    Torday, J.

    Parathyroid Hormone-related Protein (PTHrP) and its receptor represent a stretch- sensitive paracrine signaling mechanism (Torday, 1999) that may sense gravity. PTHrP has been shown to be essential for the development and homeostatic regulation of lung (Rubin et al, 2000) and bone (Kronenberg et al, 1994). Since both lung and bone structure and function are affected by microgravity, we hypothesized that microgravity down-regulates PTHrP signaling. To test this hypothesis, we suspended lung and bone cells in the microgravity environment of a rotating wall vessel apparatus, which simulates microgravity, for up to 72 hours. During the first 6-8 hours, PTHrP expression fell precipitously, decreasing by 80-90%; during the subsequent 64-66 hours, PTHrP expression remained at this newly established level. PTHrP production decreased from 5 pmol/ml/3hours to undetectable levels in culture medium from microgravity-exposed cells. The cells were then put back in culture at unit gravity for 24hours, and PTHrP expression and production returned to normal levels. Based on these findings, we have obtained bones from rats flown in space for 2 weeks (mission SLS-2, provided courtesy of the Biospecimen Facility, Ames Research Center, NASA, as a result of a peer-reviewed proposal). Analysis of PTHrP expression by femurs and tibias from these animals (n=5) revealed that PTHrP expression was 60% lower than in bones from ground-based rats. Interestingly, there were no differences in PTHrP exp ression by parietal bones, indicating that the effect of weightlessness on PTHrP expression is due to the unweighting of weight-bearing bones. This finding is consistent with other studies of microgravity-induced osteoporosis. The loss of the PTHrP signaling mechanism may be corrected using chemical agents that up-regulate this pathway.

  9. Synchronised expressions of LPXRFamide peptide and its receptor genes: seasonal, diurnal and circadian changes during spawning period in grass puffer.

    Science.gov (United States)

    Shahjahan, M; Ikegami, T; Osugi, T; Ukena, K; Doi, H; Hattori, A; Tsutsui, K; Ando, H

    2011-01-01

    Among the RFamide peptide family, the LPXRFamide peptide (LPXRFa) group regulates the release of various pituitary hormones and, recently, LPXRFa genes were found to be regulated by photoperiod via melatonin. As a first step towards investigating the role of LPXRFa on reproductive function in grass puffer (Takifugu niphobles), which spawns in semilunar cycles, genes encoding LPXRFa and its receptor (LPXRFa-R) were cloned, and seasonal, diurnal and circadian changes in their absolute amounts of mRNAs in the brain and pituitary were examined by quantitative real-time polymerase chain reaction. The grass puffer LPXRFa precursor contains two putative RFamide peptides and one possible RYamide peptide. LPXRFa and LPXRFa-R genes were extensively expressed in the diencephalon and pituitary. The expression levels of both genes were significantly elevated during the spawning periods in both sexes in the brain and pituitary, although they were low in the spawning fish just after releasing eggs and sperm. The treatment of primary pituitary cultures with goldfish LPXRFa increased the amounts of follicle-stimulating hormone β- and luteinising hormone β-subunit mRNAs. In the diencephalon, LPXRFa and LPXRFa-R genes showed synchronised diurnal and circadian variations with one peak at zeitgeber time 3 and circadian time 15, respectively. The correlated expression patterns of LPXRFa and LPXRFa-R genes in the diencephalon and pituitary and the possible stimulatory effects of LPXRFa on gonadotrophin subunit gene expression suggest the functional significance of the LPXRFa and LPXRFa-R system in the regulation of lunar-synchronised spawning of grass puffer. © 2010 The Authors. Journal of Neuroendocrinology © 2010 Blackwell Publishing Ltd.

  10. Reversal of obesity and insulin resistance by a non-peptidic glucagon-like peptide-1 receptor agonist in diet-induced obese mice.

    Directory of Open Access Journals (Sweden)

    Min He

    Full Text Available BACKGROUND: Glucagon-like peptide-1 (GLP-1 is recognized as an important regulator of glucose homeostasis. Efforts to utilize GLP-1 mimetics in the treatment of diabetes have yielded clinical benefits. A major hurdle for an effective oral therapy has been the difficulty of finding a non-peptidic GLP-1 receptor (GLP-1R agonist. While its oral bioavailability still poses significant challenges, Boc5, one of the first such compounds, has demonstrated the attainment of GLP-1R agonism in diabetic mice. The present work was to investigate whether subchronic Boc5 treatment can restore glycemic control and induce sustainable weight loss in diet-induced obese (DIO mice, an animal model of human obesity and insulin resistance. METHODOLOGY/PRINCIPAL FINDINGS: DIO mice were treated three times a week with Boc5 (0.3, 1 and 3 mg for 12 weeks. Body weight, body mass index (BMI, food intake, fasting glucose, intraperitoneal glucose tolerance and insulin induced glucose clearance were monitored regularly throughout the treatment. Glucose-stimulated insulin secretion, β-cell mass, islet size, body composition, serum metabolic profiles, lipogenesis, lipolysis, adipose hypertrophy and lipid deposition in the liver and muscle were also measured after 12 weeks of dosing. Boc5 dose-dependently reduced body weight, BMI and food intake in DIO mice. These changes were associated with significant decreases in fat mass, adipocyte hypertrophy and peripheral tissue lipid accumulation. Boc5 treatment also restored glycemic control through marked improvement of insulin sensitivity and normalization of β-cell mass. Administration of Boc5 (3 mg reduced basal but enhanced insulin-mediated glucose incorporation and noradrenaline-stimulated lipolysis in isolated adipocytes from obese mice. Furthermore, circulating leptin, adiponectin, triglyceride, total cholesterol, nonesterified fatty acid and high-density lipoprotein/low-density lipoprotein ratio were normalized to various

  11. NPR-B natriuretic peptide receptors in human corneal epithelium: mRNA, immunohistochemistochemical, protein, and biochemical pharmacology studies.

    Science.gov (United States)

    Katoli, Parvaneh; Sharif, Najam A; Sule, Anupam; Dimitrijevich, Slobodan D

    2010-07-07

    To demonstrate the presence of natriuretic peptide receptors (NPRs) in primary human corneal epithelial cells (p-CEPI), SV40-immortalized CEPI cells (CEPI-17-CL4) and in human corneal epithelium, and to define the pharmacology of natriuretic peptide (NP)-induced cGMP accumulation. NPR presence was shown by RT-PCR, western blot analysis, and indirect immunofluoresence. cGMP accumulation was determined using an enzyme immunoassay. p-CEPI and CEPI-17-CL4 cells expressed mRNAs for NPR-A and NPR-B. Proteins for both NPRs were present in these cells and in human corneal epithelium. C-type NP (CNP), atrial NP (ANP) and brain NP (BNP) stimulated the accumulation of cGMP in a concentration-dependent manner in p-CEPI cells (potency; EC(50s)): CNP (1-53 amino acids) EC(50)=24+/-5 nM; CNP fragment (32-53 amino acids) EC(50)=51+/-8 nM; ANP (1-28 amino acids) EC(50)=>10 microM; BNP (32 amino acids) EC(50)>10 microM (all n=3-4). While the NPs were generally more potent in the CEPI-17-CL4 cells than in p-CEPI cells (n=4-9; p<0.01), the rank order of potency of the peptides was essentially the same in both cell types. Effects of CNP fragment in p-CEPI and CEPI-17-CL4 cells were potently blocked by HS-142-1, an NPR-B receptor subtype-selective antagonist (K(i)=0.25+/-0.05 microM in CEPI-CL4-17; K(i)=0.44+/-0.09 microM in p-CEPIs; n=6-7) but less so by an NPR-A receptor antagonist, isatin (K(i)=5.3-7.8 microM, n=3-7). Our studies showed the presence of NPR-A and NPR-B (mRNAs and protein) in p-CEPI and CEPI-17-CL4 cells and in human corneal epithelial tissue. However, detailed pharmacological studies revealed NPR-B to be the predominant functionally active receptor in both cell-types whose activation leads to the generation of cGMP. While the physiologic role(s) of the NP system in corneal function remains to be delineated, our multidisciplinary findings pave the way for such future investigations.

  12. The role of patient-based treatment planning in peptide receptor radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardiansyah, Deni; Attarwala, Ali Asgar [Heidelberg University, Medical Radiation Physics/Radiation Protection, Universitaetsmedizin Mannheim, Medical Faculty Mannheim, Mannheim (Germany); Universitaetsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Department of Radiation Oncology, Mannheim (Germany); Maass, Christian; Glatting, Gerhard [Heidelberg University, Medical Radiation Physics/Radiation Protection, Universitaetsmedizin Mannheim, Medical Faculty Mannheim, Mannheim (Germany); Mueller, Berthold [University Hospital, RWTH Aachen University, Klinik fuer Nuklearmedizin, Aachen (Germany); Kletting, Peter [Universitaet Ulm, Klinik fuer Nuklearmedizin, Ulm (Germany); Mottaghy, Felix M. [University Hospital, RWTH Aachen University, Klinik fuer Nuklearmedizin, Aachen (Germany); Maastricht University Medical Center (MUMC+), Department of Nuclear Medicine, Maastricht (Netherlands)

    2016-05-15

    Accurate treatment planning is recommended in peptide-receptor radionuclide therapy (PRRT) to minimize the toxicity to organs at risk while maximizing tumor cell sterilization. The aim of this study was to quantify the effect of different degrees of individualization on the prediction accuracy of individual therapeutic biodistributions in patients with neuroendocrine tumors (NETs). A recently developed physiologically based pharmacokinetic (PBPK) model was fitted to the biokinetic data of 15 patients with NETs after pre-therapeutic injection of {sup 111}In-DTPAOC. Mathematical phantom patients (MPP) were defined using the assumed true (true MPP), mean (MPP 1A) and median (MPP 1B) parameter values of the patient group. Alterations of the degree of individualization were introduced to both mean and median patients by including patient-specific information as a priori knowledge: physical parameters and hematocrit (MPP 2A/2B). Successively, measurable individual biokinetic parameters were added: tumor volume V{sub tu} (MPP 3A/3B), glomerular filtration rate GFR (MPP 4A/4B), and tumor perfusion f{sub tu} (MPP 5A/5B). Furthermore, parameters of MPP 5A/5B and a simulated {sup 68}Ga-DOTATATE PET measurement 60 min p.i. were used together with the population values used as Bayesian parameters (MPP 6A/6B). Therapeutic biodistributions were simulated assuming an infusion of {sup 90}Y-DOTATATE (3.3 GBq) over 30 min to all MPPs. Time-integrated activity coefficients were predicted for all MPPs and compared to the true MPPs for each patient in tumor, kidneys, spleen, liver, remainder, and whole body to obtain the relative differences RD. The large RD values of MPP 1A [RD{sub tumor} = (625 ± 1266)%, RD{sub kidneys} = (11 ± 38)% ], and MPP 1B [RD{sub tumor} = (197 ± 505)%, RD{sub kidneys} = (11 ± 39)% ] demonstrate that individual treatment planning is needed due to large physiological differences between patients. Although addition of individual patient parameters reduced the

  13. Peptide receptor radionuclide therapy with {sup 90}Y/{sup 177}Lu-labelled peptides for inoperable head and neck paragangliomas (glomus tumours)

    Energy Technology Data Exchange (ETDEWEB)

    Puranik, Ameya D.; Kulkarni, Harshad R.; Singh, Aviral; Baum, Richard P. [Zentralklinik Bad Berka, THERANOSTICS Centre for Molecular Radiotherapy and Molecular Imaging, ENETS Center of Excellence, Bad Berka (Germany)

    2015-07-15

    Head and neck paragangliomas (HNPGLs) are rare tumours arising from autonomic nervous system ganglia. Although surgery offers the best chance of complete cure, there is associated morbidity due to the crucial location of these tumours. Radiotherapy arrests tumour growth and provides symptomatic improvement, but has long-term consequences. These tumours express somatostatin receptors (SSTR) and hence peptide receptor radionuclide therapy (PRRT) is now a treatment option. We assessed the molecular, morphological and clinical responses of inoperable HNPGLs to PRRT. Nine patients with inoperable HNPGL assessed between June 2006 and June 2014 were included. Four patients had a solitary lesion, four had multifocal involvement and one had distant metastases (bone and lungs). The patients were treated with PRRT using {sup 90}Y/{sup 177}Lu-labelled peptides after positive confirmation of SSTR expression on {sup 68}Ga-DOTATOC PET/CT. All patients received two to four courses of PRRT. Subsequent serial imaging with {sup 68}Ga-DOTATOC PET/CT was carried out every 6 months to assess response to treatment. Clinical (symptomatic) response was also assessed. Based on molecular response (EORTC) criteria, four of the nine patients showed a partial molecular response to treatment seen as significant decreases in SUV{sub max}, accompanied by a reduction in tumour size. Five patients showed stable disease on both molecular and morphological criteria. Six out of nine patients were symptomatic at presentation with manifestations of cranial nerve involvement, bone destruction at the primary site and metastatic bone pain. Molecular responses were correlated with symptomatic improvement in four out of these six patients; while two patients showed small reductions in tumour size and SUV{sub max}. The three asymptomatic patients showed no new lesions or symptomatic worsening. PRRT was effective in all patients, with no disease worsening seen, either in the form of neurological symptoms or

  14. Structure of the Human Angiotensin II Type 1 (AT1) Receptor Bound to Angiotensin II from Multiple Chemoselective Photoprobe Contacts Reveals a Unique Peptide Binding Mode*

    Science.gov (United States)

    Fillion, Dany; Cabana, Jérôme; Guillemette, Gaétan; Leduc, Richard; Lavigne, Pierre; Escher, Emanuel

    2013-01-01

    Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs. PMID:23386604

  15. The Effect of Glucagon-Like Peptide 1 Receptor Agonists on Weight Loss in Type 2 Diabetes: A Systematic Review and Mixed Treatment Comparison Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Jessica E Potts

    Full Text Available To determine the effects of glucagon-like peptide-1 receptor agonists compared with placebo and other anti-diabetic agents on weight loss in overweight or obese patients with type 2 diabetes mellitus.Electronic searches were conducted for randomised controlled trials that compared a glucagon-like peptide-1 receptor agonist therapy at a clinically relevant dose with a comparator treatment (other type 2 diabetes treatment or placebo in adults with type 2 diabetes and a mean body mass index ≥ 25 kg/m2. Pair-wise meta-analyses and mixed treatment comparisons were conducted to examine the difference in weight change at six months between the glucagon-like peptide-1 receptor agonists and each comparator.In the mixed treatment comparison (27 trials, the glucagon-like peptide-1 receptor agonists were the most successful in terms of weight loss; exenatide 2 mg/week: -1.62 kg (95% CrI: -2.95 kg, -0.30 kg, exenatide 20 μg: -1.37 kg (95% CI: -222 kg, -0.52 kg, liraglutide 1.2 mg: -1.01 kg (95%CrI: -2.41 kg, 0.38 kg and liraglutide 1.8 mg: -1.51 kg (95% CI: -2.67 kg, -0.37 kg compared with placebo. There were no differences between the GLP-1 receptor agonists in terms of weight loss.This review provides evidence that glucagon-like peptide-1 receptor agonist therapies are associated with weight loss in overweight or obese patients with type 2 diabetes with no difference in weight loss seen between the different types of GLP-1 receptor agonists assessed.

  16. Comparative biodistribution of 12 111In-labelled gastrin/CCK2 receptor-targeting peptides

    NARCIS (Netherlands)

    P. Laverman (Peter); L. Joosten; A. Eek (Annemarie); S. Roosenburg (Susan); P.K. Peitl; T. Maina (Theodosia); H. Mäcke (Helmut); L. Aloj (Luigi); E. von Guggenber (Elisabeth); J.K. Sosabowski (Jane); M. de Jong (Marion); J.-C. Reubi (Jean-Claude); W.J.G. Oyen (Wim); O.C. Boerman (Otto)

    2011-01-01

    textabstractPurpose Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide

  17. Real-time trafficking and signaling of the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Wismann, Pernille; Underwood, Christina Rye

    2014-01-01

    . A fundamental mechanism controlling the signaling capacity of GPCRs is the post-endocytic trafficking of receptors between recycling and degradative fates. Here, we combined microscopy with novel real-time assays to monitor both receptor trafficking and signaling in living cells. We find that the human GLP-1R...

  18. Vasopressin-related peptides increase the hippocampal corticosterone receptor capacity of diabetes insipidus (Brattleboro) rats

    NARCIS (Netherlands)

    Veldhuis, H D; de Kloet, E R

    The binding of [3H]corticosterone to receptors in cytosol of several brain regions and of [3H]dexamethasone to receptors in pituitary cytosol was measured after chronic treatment of homozygous diabetes insipidus rats (Ho-Di) with various neuropeptides. All rats were adrenalectomized 24 h before

  19. Ligand binding and activation mechanism og the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye

    endogenous agonist, Glucagon-Like Peptide-1 (GLP-1), has a number of physiological effects that contribute to reducing blood sugar and body weight. Therefore, GLP-1R has become a promising target for the treatment of type 2 diabetes (T2D). The overall purpose of the Ph.D. project has been to investigate how...

  20. Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes

    DEFF Research Database (Denmark)

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

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion...

  1. Synthesis of (68)Ga-labeled NOTA-RGD-GE11 heterodimeric peptide for dual integrin and epidermal growth factor receptor-targeted tumor imaging.

    Science.gov (United States)

    Yu, Hung-Man; Chen, Jyun-Hong; Lin, Kun-Liang; Lin, Wuu-Jyh

    2015-06-15

    Radiolabeled Arg-Gly-Asp (RGD) peptide analogs have been extensively studied for αvβ3 integrin-targeted angiogenesis imaging. According to recently presented evidence, the dodecapeptide GE11 has high affinity to the epidermal growth factor receptor (EGFR), which is overexpressed in many types of cancer. Dual-receptor molecular imaging probes with two different heterodimeric peptides exhibit improved cancer targeting efficacy. In the present study, the design and synthesis of a new RGD-GE11 peptide heterodimer for dual αvβ3 integrin/EGFR-targeted cancer imaging are described. The RGD-GE11 heterodimer was linked with 6-aminohexanoic acid (6-Ahx) and cysteine and conjugated with 1,4,7-triazacyclononane-N,N',N″-triacetic acid (NOTA) to form NOTA-RGD-cys-6-Ahx-GE11. The monomeric peptides, NOTA-cys-6-Ahx-GE11 and c(RGDyK), were formed by a peptide synthesizer. The peptide heterodimer NOTA-RGD-GE11 was obtained by NOTA-cys-6-Ahx-GE11 and maleimidopropyl-c(RGDyK) conjugation with a thioether linkage. The NOTA peptide conjugate was labeled with freshly eluted (68)Ga and purified using reversed-phase high-performance liquid chromatography. The (68)Ga-NOTA-RGD-cys-6-Ahx-GE11 was successfully prepared, in this study, with a radiochemical yield of 85% and a radiochemical purity of >98%. These results warrant further investigation of this heterodimeric peptide's binding affinity to the receptors. Copyright © 2015 John Wiley & Sons, Ltd.

  2. Cytotoxic agents directed to peptide hormone receptors: defining the requirements for a successful drug.

    Science.gov (United States)

    Czerwinski, G; Tarasova, N I; Michejda, C J

    1998-09-29

    In principle, cell surface receptors that are overexpressed in tumor tissue could serve as targets for anticancer drugs attached to receptor ligands. The purpose of this paper is to identify the necessary elements for a successful receptor-targeted drug. We used the gastrin/cholecystokinin type B receptor as a model delivery system, and we report on the synthesis, trafficking, and in vitro and in vivo evaluation of heptagastrin, the C-terminal heptapeptide of gastrin, linked via an appropriate linker to a potently cytotoxic ellipticine derivative, 1-[3-[N-(3-aminopropyl)-N-methylamino]propyl]amino-9-methoxy-5, 11-dimethyl-6H-pyrido[4,3-b]carbazole. These data, and previous work from our laboratory, show that the drug-complexed ligand is sorted to lysosomes whereas the receptor is recycled to the plasma membrane. The lysosomal processing of the ligand/drug construct depends on the linker between the ligand sequence and the cytotoxic moiety. We show that heptagastrin linked to ellipticine via a succinoyl-substituted pentapeptide, AlaLeuAlaLeuAla, is at least 10(3) more toxic to cholecystokinin type B receptor-positive NIH/3T3 cells than to isogenic NIH/3T3 cells lacking the receptor. The conjugated drug eradicated all receptor-positive tumor cells in vivo without producing any general toxicity. The data indicate that the density of the cell surface receptor, the properties of the cytotoxic moiety, and the correct processing of the drug-conjugated ligand in lysosomes are crucial to the effectiveness of a receptor-targeted drug.

  3. Dipeptidylpeptidase-4 (DPP-4) inhibitors are favourable to glucagon-like peptide-1 (GLP-1) receptor agonists: yes.

    Science.gov (United States)

    Scheen, André J

    2012-03-01

    The pharmacological treatment of type 2 diabetes (T2DM) is becoming increasingly complex, especially since the availability of incretin-based therapies. Compared with other glucose-lowering strategies, these novel drugs offer some advantages such as an absence of weight gain and a negligible risk of hypoglycaemia and, possibly, better cardiovascular and β-cell protection. The physician has now multiple choices to manage his/her patient after secondary failure of metformin, and the question whether it is preferable to add an oral dipeptidylpeptidase-4 (DPP-4) inhibitor (gliptin) or an injectable glucagon-like peptide-1 (GLP-1) receptor agonist will emerge. Obviously, DPP-4 inhibitors offer several advantages compared with GLP-1 receptor agonists, especially regarding easiness of use, tolerance profile and cost. However, because they can only increase endogenous GLP-1 concentrations to physiological (rather than pharmacological) levels, they are less potent to improve glucose control, promote weight reduction ("weight neutrality") and reduce blood pressure compared to GLP-1 receptor agonists. Of note, none of the two classes have proven long-term safety and positive impact on diabetic complications yet. The role of DPP-4 inhibitors and GLP-1 receptor agonists in the therapeutic armamentarium of T2DM is rapidly evolving, but their respective potential strengths and weaknesses should be better defined in long-term head-to-head comparative controlled trials. Instead of trying to answer the question whether DPP-4 inhibitors are favourable to GLP-1 receptor agonists (or vice versa), it is probably more clinically relevant to look at which T2DM patient will benefit more from one or the other therapy considering all his/her individual clinical characteristics ("personalized medicine"). Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  4. Activation of the insulin receptor (IR) by insulin and a synthetic peptide has different effects on gene expression in IR-transfected L6 myoblasts

    DEFF Research Database (Denmark)

    Jensen, M.; Palsgaard, J.; Borup, R.

    2008-01-01

    Single-chain peptides have been recently produced that display either mimetic or antagonistic properties against the insulin and IGF-1 (insulin-like growth factor 1) receptors. We have shown previously that the insulin mimetic peptide S597 leads to significant differences in receptor activation...... and initiation of downstream signalling cascades despite similar binding affinity and in vivo hypoglycaemic potency. It is still unclear how two ligands can initiate different signalling responses through the IR (insulin receptor). To investigate further how the activation of the IR by insulin and S597...... differentially activates post-receptor signalling, we studied the gene expression profile in response to IR activation by either insulin or S597 using microarray technology. We found striking differences between the patterns induced by these two ligands. Most remarkable was that almost half of the genes...

  5. Autocrine Interleukin-10 Mediates Glucagon-Like Peptide-1 Receptor-Induced Spinal Microglial β-Endorphin Expression.

    Science.gov (United States)

    Wu, Hai-Yun; Tang, Xue-Qi; Mao, Xiao-Fang; Wang, Yong-Xiang

    2017-11-29

    The glucagon-like peptide-1 (GLP-1) receptor agonist exenatide stimulates microglial β-endorphin expression and subsequently produces neuroprotection and antinociception. This study illustrated an unrecognized autocrine role of IL-10 in mediation of exenatide-induced β-endorphin expression. Treatment with exenatide in cultured primary spinal microglia concentration dependently stimulated the expression of the M2 microglial markers IL-10, IL-4, Arg 1, and CD206, but not the M1 microglial markers TNF-α, IL-1β, IL-6, or CD68. Intrathecal exenatide injection also significantly upregulated spinal microglial expression of IL-10, IL-4, Arg 1, and CD206, but not TNF-α, IL-1β, IL-6, or CD68. Intrathecal injection of exenatide stimulated spinal microglial expression of IL-10 and β-endorphin in neuropathic rats. Furthermore, treatment with IL-10 (but not IL-4) stimulated β-endorphin expression in cultured primary microglia, whereas treatment with β-endorphin failed to increase IL-10 expression. The IL-10-neutralizing antibody entirely blocked exenatide-induced spinal microglial expression of β-endorphin in vitro and in vivo and fully blocked exenatide mechanical antiallodynia in neuropathic rats. Moreover, specific cAMP/PKA/p38 signal inhibitors and siRNA/p38β, but not siRNA/p38α, completely blocked exenatide-induced IL-10 expression in cultured primary microglia. Knock-down of IL-10 receptor-α mRNA using siRNA fully inhibited exenatide-induced spinal microglial β-endorphin expression and mechanical antiallodynia in neuropathy. Exenatide also markedly stimulated phosphorylation of the transcription factor STAT3 in cultured primary microglia and β-endorphin stimulation was completely inhibited by the specific STAT3 activation inhibitor. These results revealed that IL-10 in microglia mediated β-endorphin expression after GLP-1 receptor activation through the autocrine cAMP/PKA/p38β/CREB and subsequent IL-10 receptor/STAT3 signal pathways. SIGNIFICANCE STATEMENT

  6. Cyclic-RGDfK peptide conjugated succinoyl-TPGS nanomicelles for targeted delivery of docetaxel to integrin receptor over-expressing angiogenic tumours.

    Science.gov (United States)

    Kulhari, Hitesh; Pooja, Deep; Shrivastava, Shweta; Telukutala, Srinivasa R; Barui, Ayan K; Patra, Chitta Ranjan; Naidu Vegi, Ganga Modi; Adams, David J; Sistla, Ramakrishna

    2015-08-01

    Docetaxel (DTX) is an anticancer drug that is used alone and in combination with other drugs to treat tumours. However, it suffers from the drawback of non-specific cytotoxicity. To improve the therapeutic potential of DTX, we report the synthesis of cRGDfK peptide-conjugated succinoyl-TPGS (tocopheryl polyethylene glycol succinate) nanomicelles for targeted delivery of DTX. Among RGD (Arg-Gly-Asp) peptides, cRGDfK peptide shows specificity towards αvβ3 integrin receptors that are most commonly over-expressed in tumour cells. To cRGDfK peptide, succinoylated TPGS was synthesised and conjugated to cRGDfK peptide using a carbodiimide reaction. Peptide-conjugated DTX loaded nanomicelles (PDNM) displayed small particle size with a narrow distribution, controlled drug release and high physicochemical stability. Cytotoxicity, cellular uptake, apoptosis and anti-angiogenic comparisons of unconjugated nanomicelles to PDNM in DU145 human prostate cancer cells and HUVECs (Human Umblical Vein Endothelial Cells) clearly revealed the importance of the cRGDfK peptide in enhancing the drug delivery performance of nanomicelles. Common to many chemotherapeutic agents for cancer, systemic toxicity remains a big concern. In this article, the authors attempted to address this issue by conjugating RGD based peptides to Docetaxel, which would target integrins expressed on tumor cell surface. The experimental data revealed enhanced drug delivery. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Integrative function of adrenaline receptors for glucagon-like peptide-1 exocytosis in enteroendocrine L cell line GLUTag.

    Science.gov (United States)

    Harada, Kazuki; Kitaguchi, Tetsuya; Tsuboi, Takashi

    2015-05-15

    Adrenaline reacts with three types of adrenergic receptors, α1, α2 and β-adrenergic receptors (ARs), inducing many physiological events including exocytosis. Although adrenaline has been shown to induce glucagon-like peptide-1 (GLP-1) secretion from intestinal L cells, the precise molecular mechanism by which adrenaline regulates GLP-1 secretion remains unknown. Here we show by live cell imaging that all types of adrenergic receptors are stimulated by adrenaline in enteroendocrine L cell line GLUTag cells and are involved in GLP-1 exocytosis. We performed RT-PCR analysis and found that α1B-, α2A-, α2B-, and β1-ARs were expressed in GLUTag cells. Application of adrenaline induced a significant increase of intracellular Ca(2+) and cAMP concentration ([Ca(2+)]i and [cAMP]i, respectively), and GLP-1 exocytosis in GLUTag cells. Blockade of α1-AR inhibited adrenaline-induced [Ca(2+)]i increase and exocytosis but not [cAMP]i increase, while blockade of β1-AR inhibited adrenaline-induced [cAMP]i increase and exocytosis but not [Ca(2+)]i increase. Furthermore, overexpression of α2A-AR suppressed the adrenaline-induced [cAMP]i increase and exocytosis. These results suggest that the fine-turning of GLP-1 secretion from enteroendocrine L cells is established by the balance between α1-, α2-, and β-ARs activation. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Amyloid β peptide directly impairs pineal gland melatonin synthesis and melatonin receptor signaling through the ERK pathway.

    Science.gov (United States)

    Cecon, Erika; Chen, Min; Marçola, Marina; Fernandes, Pedro A C; Jockers, Ralf; Markus, Regina P

    2015-06-01

    Melatonin is the hormone produced by the pineal gland known to regulate physiologic rhythms and to display immunomodulatory and neuroprotective properties. It has been reported that Alzheimer disease patients show impaired melatonin production and altered expression of the 2 G protein-coupled melatonin receptors (MTRs), MT₁ and MT₂, but the underlying mechanisms are not known. Here we evaluated whether this dysfunction of the melatonergic system is directly caused by amyloid β peptides (Aβ(1-40) and Aβ(1-42)). Aβ treatment of rat pineal glands elicited an inflammatory response within the gland, evidenced by the up-regulation of 52 inflammatory genes, and decreased the production of melatonin up to 75% compared to vehicle-treated glands. Blocking NF-κB activity prevented this effect. Exposure of HEK293 cells stably expressing recombinant MT₁ or MT₂ receptors to Aβ lead to a 40% reduction in [(125)I]iodomelatonin binding to MT₁. ERK1/2 activation triggered by MTRs, but not by the β₂-adrenergic receptor, was markedly impaired by Aβ in HEK293 transfected cells, as well as in primary rat endothelial cells expressing endogenous MTRs. Our data reveal the melatonergic system as a new target of Aβ, opening new perspectives to Alzheimer disease diagnosis and therapeutic intervention. © FASEB.

  9. [Mechanism on atrial natriuretic peptide receptor in anti-anxiety with acupuncture based on its tranquilizing effect].

    Science.gov (United States)

    He, Wei; Zhou, Qizhi; Yu, Shuguang; Cai, Dingjun; Wang, Qiang; Zhang, Xiaodan; Huang, Wen-qin

    2015-01-01

    Anxiety disorder is one of the most common mental disorders and seriously impairs the physical and mental health of patients. Due to the efficacy of acupuncture for tranquilization, acupuncture displays its unique advantage on the treatment of anxiety disorder, but the relevant biological mechanism has not been elaborated. The modern medicine study has proved that the heart and brain have their own independent natriuretic peptide (NP) system. The dysfunction of ANP and its receptor are closely related to the occurrence of anxiety disorder. The ANP acts on anti-anxiety. Hence, focusing on the three aspects, named the anti-anxiety effect of acupuncture based on its tranquilizing effect, the anti-anxiety effect of ANP and the positive regulation of acupuncture on NP, the mechanism on ANP and its receptor was explored in anti-anxiety with acupuncture based on tranquilizing effect, and the idea was put forward on that the anti-anxiety effect of acupuncture was possibly based on its action of tranquilization through regulating the ANP and its receptor. As a result, it is expected to provide the theoretic support for the mechanism study on anti-anxiety with acupuncture based on its tranquilizing effect.

  10. Vasoactive intestinal peptide receptor on liver plasma membranes: Solubilization and cross-linking

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, T.D.; Kaiser, L.M. (Duke Univ., Durham, NC (USA))

    1990-11-01

    The hepatic receptor for VIP was solubilized from rat liver plasma membranes with 1.4% digitonin and shown to conserve its ability to bind to the ligand. This solubilized receptor demonstrated the high affinity and specificity for VIP (KD approximately 1 nM, binding preference: VIP greater than PHI greater than secretin greater than thymosin alpha 1) which were observed with the nonsolubilized VIP receptor on intact liver plasma membranes. {sup 125}I-VIP was next cross-linked to either the solubilized or nonsolubilized receptor using disuccinimido suberate or disuccinimido dithiobis(propionate), and the resulting complexes analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. A broad autoradiographic band which demonstrated a high affinity for VIP was identified at Mr 56,000 (53,000 in the absence of the reducing agent dithiothreitol) for both the solubilized and nonsolubilized receptors. We have thus been able to solubilize from rat liver plasma membranes a receptor with high affinity and specificity for VIP, and confirmed its structural similarity with the native VIP receptor in nonsolubilized membranes using cross-linking techniques.

  11. Targeting of vasoactive intestinal peptide receptor 2, VPAC2, a secretin family G-protein coupled receptor, to primary cilia

    Directory of Open Access Journals (Sweden)

    Livana Soetedjo

    2013-05-01

    Primary cilia protrude from the cell surface of many cell types in the human body and function as cellular antennae via ciliary membrane localized receptors. Neurons and glial cells in the brain possess primary cilia, and the malfunction of primary cilia may contribute to neurological deficits present in many cilia-associated disorders. Several rhodopsin family G-protein coupled receptors (GPCRs are specifically localized to a subset of neuronal primary cilia. However, whether other family GPCRs target to neuronal cilia and whether glial primary cilia harbor any GPCRs are not known. We conducted a screening of GPCRs to determine their ability to target to primary cilia, and identified a secretin family member, Vasoactive Intestinal Receptor 2 (VPAC2, as a novel ciliary GPCR. Here, we show that endogenous VPAC2 targets to primary cilia in various brain regions, including the suprachiasmatic nuclei and the thalamus. Surprisingly, VPAC2 not only localizes to neuronal cilia but also to glial cilia. In addition, we show that VPAC2's C-terminus is both necessary and sufficient for its ciliary targeting and we define a novel ciliary targeting signal: the tetrapeptide RDYR motif in the C-terminus of VPAC2. Furthermore, we demonstrate that VPAC2 ciliary targeting is dependent on Tubby, the BBSome (a complex of Bardet–Biedl syndrome proteins and the BBSome targeting factor, Arl6.

  12. Inhibition of atrial natriuretic peptide (ANP) C receptor expression by antisense oligodeoxynucleotides in A10 vascular smooth-muscle cells is associated with attenuation of ANP-C-receptor-mediated inhibition of adenylyl cyclase.

    OpenAIRE

    Palaparti, A; Li, Y; Anand-Srivastava, M B

    2000-01-01

    Atrial natriuretic peptide (ANP) mediates a variety of physiological effects through its interaction with ANP-A, ANP-B or ANP-C receptors. However, controversies exist regarding the involvement of ANP-C receptor and adenylyl cyclase/cAMP signal-transduction systems to which these receptors are coupled in mediating these responses. In the present studies, we have employed an antisense approach to eliminate the ANP-C receptor and to examine the effect of this elimination on adenylyl cyclase inh...

  13. DNA display selection of peptide ligands for a full-length human G protein-coupled receptor on CHO-K1 cells.

    Directory of Open Access Journals (Sweden)

    Nobuhide Doi

    Full Text Available The G protein-coupled receptors (GPCRs, which form the largest group of transmembrane proteins involved in signal transduction, are major targets of currently available drugs. Thus, the search for cognate and surrogate peptide ligands for GPCRs is of both basic and therapeutic interest. Here we describe the application of an in vitro DNA display technology to screening libraries of peptide ligands for full-length GPCRs expressed on whole cells. We used human angiotensin II (Ang II type-1 receptor (hAT1R as a model GPCR. Under improved selection conditions using hAT1R-expressing Chinese hamster ovary (CHO-K1 cells as bait, we confirmed that Ang II gene could be enriched more than 10,000-fold after four rounds of selection. Further, we successfully selected diverse Ang II-like peptides from randomized peptide libraries. The results provide more precise information on the sequence-function relationships of hAT1R ligands than can be obtained by conventional alanine-scanning mutagenesis. Completely in vitro DNA display can overcome the limitations of current display technologies and is expected to prove widely useful for screening diverse libraries of mutant peptide and protein ligands for receptors that can be expressed functionally on the surface of CHO-K1 cells.

  14. Hormone-Related Migraine Headaches and Mood Disorders: Treatment with Estrogen Stabilization.

    Science.gov (United States)

    Warnock, Julia K; Cohen, Lawrence J; Blumenthal, Harvey; Hammond, Jordan E

    2017-01-01

    Because estrogens and the trigeminal system are inherently linked, prescribers who are treating a woman with a hormonally related mood disorder and migraine headaches should consider hormonal options to optimize the patient's treatment. This article discusses the interrelationships of estrogen, serotonin, and the trigeminal system as they relate to menstrual migraine occurrence and hormone-related mood symptoms. In addition, clinical examples are provided to facilitate the prescribers treating women during reproductive transitions in which declining estrogens are related to their suffering. © 2016 Pharmacotherapy Publications, Inc.

  15. Characterization of the receptor binding residues of kisspeptins by positional scanning using peptide photoaffinity probes.

    OpenAIRE

    Misu, Ryosuke; Oishi, Shinya; Setsuda, Shohei; Noguchi, Taro; Kaneda, Masato; Ohno, Hiroaki; Evans, Barry; Navenot, Jean-Marc; Peiper, Stephen C.; Fujii, Nobutaka

    2013-01-01

    Kisspeptins, endogenous peptide ligands for GPR54, play an important role in GnRH secretion. Since in vivo administration of kisspeptins induces increased plasma LH levels, GPR54 agonists hold promise as therapeutic agents for the treatment of hormonal secretion diseases. To facilitate the design of novel potent GPR54 ligands, residues in kisspeptins that involve in the interaction with GPR54 were investigated by kisspeptin-based photoaffinity probes. Herein, we report the design and synthesi...

  16. Improving Antigenic Peptide Vaccines for Cancer Immunotherapy Using a Dominant Tumor-specific T Cell Receptor*

    Science.gov (United States)

    Buhrman, Jonathan D.; Jordan, Kimberly R.; Munson, Daniel J.; Moore, Brandon L.; Kappler, John W.; Slansky, Jill E.

    2013-01-01

    Vaccines that incorporate peptide mimics of tumor antigens, or mimotope vaccines, are commonly used in cancer immunotherapy and function by eliciting increased numbers of T cells that cross-react with the native tumor antigen. Unfortunately, they often elicit T cells that do not cross-react with or that have low affinity for the tumor antigen. Using a high affinity tumor-specific T cell clone, we identified a panel of mimotope vaccines for the dominant peptide antigen from a mouse colon tumor that elicits a range of tumor protection following vaccination. The TCR from this high affinity T cell clone was rarely identified in ex vivo evaluation of tumor-specific T cells elicited by mimotope vaccination. Conversely, a low affinity clone found in the tumor and following immunization was frequently identified. Using peptide libraries, we determined if this frequently identified TCR improved the discovery of efficacious mimotopes. We demonstrated that the representative TCR identified more protective mimotopes than the high affinity TCR. These results suggest that targeting a dominant fraction of tumor-specific T cells generates potent immunity and that consideration of the available T cell repertoire is necessary for targeted T cell therapy. These results have important implications when optimizing mimotope vaccines for cancer immunotherapy. PMID:24106273

  17. G-Protein-coupled receptors as potential drug candidates in preeclampsia: targeting the relaxin/insulin-like family peptide receptor 1 for treatment and prevention.

    Science.gov (United States)

    Conrad, Kirk P

    2016-09-01

    Important roles for G-protein-coupled receptors (GPCRs) have been identified in the maternal physiological adaptations to pregnancy and in the pathogenesis of preeclampsia. On this basis, GPCRs are potential therapeutic targets for preeclampsia. In this review, vasopressin and apelin are initially considered in this context before the focus on the hormone relaxin and its cognate receptor, the relaxin/insulin-like family peptide receptor 1 (RXFP1). Based on both compelling scientific rationale and a promising safety profile, the relaxin ligand-receptor system is comprehensively evaluated as a potential therapeutic endpoint in preeclampsia. The published literature relating to the topic was searched through January 2016 using PubMed. Relaxin is a peptide hormone secreted by the corpus luteum; it circulates in the luteal phase and during pregnancy. Activation of RXFP1 is vasodilatory; thus, relaxin supplementation is expected to at least partly restore the fundamental vasodilatory changes of normal pregnancy, thereby alleviating maternal organ hypoperfusion, which is a major pathogenic manifestation of severe preeclampsia. Specifically, by exploiting its pleiotropic hemodynamic attributes in preeclampsia, relaxin administration is predicted to (i) reverse robust arterial myogenic constriction; (ii) blunt systemic and renal vasoconstriction in response to activation of the angiotensin II receptor, type 1; (iii) mollify the action of endogenous vasoconstrictors on uterine spiral arteries with failed remodeling and retained smooth muscle; (iv) increase arterial compliance; (v) enhance insulin-mediated glucose disposal by promoting skeletal muscle vasodilation and (vi) mobilize and activate bone marrow-derived angiogenic progenitor cells, thereby repairing injured endothelium and improving maternal vascularity in organs such as breast, uterus, pancreas, skin and fat. By exploiting its pleiotropic molecular attributes in preeclampsia, relaxin supplementation is

  18. A 5'-upstream short open reading frame encoded peptide regulates angiotensin type 1a receptor production and signalling via the β-arrestin pathway.

    Science.gov (United States)

    Yosten, Gina L C; Liu, Jun; Ji, Hong; Sandberg, Kathryn; Speth, Robert; Samson, Willis K

    2016-03-15

    AUG sequences and short open reading frames are commonly present in the 5'-leader sequence of G protein-coupled receptor mRNAs. The presence of these upstream AUG sequences has been demonstrated to inhibit downstream receptor translation efficiency and, most recently, receptor signal transduction. A seven amino acid peptide encoded by a short open reading frame in exon 2 of the angiotensin type 1a receptor has been shown to inhibit non-G protein-coupled signalling of angiotensin II, without altering the classical G protein-coupled pathway activated by the ligand. This finding may lead to the development of a new class of angiotensin receptor antagonists with activities biased for one, but not all, of the signalling cascades activated by angiotensin II, which could have therapeutic implications for the myriad hormones and neurotransmitters that signal through G protein-coupled receptors. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  19. A 5′‐upstream short open reading frame encoded peptide regulates angiotensin type 1a receptor production and signalling via the β‐arrestin pathway

    Science.gov (United States)

    Yosten, Gina L.C.; Liu, Jun; Ji, Hong; Sandberg, Kathryn; Speth, Robert

    2015-01-01

    Abstract AUG sequences and short open reading frames are commonly present in the 5′‐leader sequence of G protein‐coupled receptor mRNAs. The presence of these upstream AUG sequences has been demonstrated to inhibit downstream receptor translation efficiency and, most recently, receptor signal transduction. A seven amino acid peptide encoded by a short open reading frame in exon 2 of the angiotensin type 1a receptor has been shown to inhibit non‐G protein‐coupled signalling of angiotensin II, without altering the classical G protein‐coupled pathway activated by the ligand. This finding may lead to the development of a new class of angiotensin receptor antagonists with activities biased for one, but not all, of the signalling cascades activated by angiotensin II, which could have therapeutic implications for the myriad hormones and neurotransmitters that signal through G protein‐coupled receptors. PMID:26333095

  20. The transferrin receptor of Actinobacillus pleuropneumoniae: Quantitation of expression and structural characterization using a peptide-specific monoclonal antibody

    DEFF Research Database (Denmark)

    Bøg, Yang S.; Andresen, Lars Ole; Bastholm, L.

    2001-01-01

    When Actinobacillus pleuropneumoniae (A. pp) is grown under iron-restricted conditions in vitro, transferrin binding proteins (Tbps) are induced. The functional transferrin receptor of A. pp is composed of two outer membrane proteins (Tbp1 and Tbp2) and shows an exquisite specificity for porcine...... transferrin. This complex was studied using a monoclonal antibody (Mab 1.48) raised against a synthetic peptide corresponding to a hydrophilic domain of Tbp2 common to several A. pp serotypes. The antibody reacted specifically with a 60-70 kDa Tbp2-antigen found in all serotypes of A. pp obtained from iron......-restricted culture. It was found that Tbp2 was not expressed in iron replete medium by any serotype except serotypes 5a, 5b and 6 where a weak expression was seen. There was a weak expression of related antigens in Actinobacillus indolicus and Actinobacillus suis under iron-depleted conditions while no similar...

  1. [Effects of glucagon-like peptide-1 receptor agonists on cardiovascular risk factors and the cardiovascular system].

    Science.gov (United States)

    Fiorentino, Teresa Vanessa; Sesti, Giorgio

    2016-12-01

    The results of the cardiovascular outcome trials comparing the SGLT2 inhibitor empagliflozin and the glucagon-like peptide-1 receptor agonist liraglutide to placebo have been recently published. Interestingly, empagliflozin and liraglutide treatments significantly reduce cardiovascular events in subjects with type 2 diabetes. The mechanisms underlying the observed cardioprotective effects of empagliflozin and liraglutide are speculative and future studies are needed to better understand these results. However, since reduction in the primary outcome was evident 3 months after starting empagliflozin and 24 months after starting liraglutide, it is tempting to hypothesize that the cardiovascular benefits observed in diabetic patients treated with empagliflozin are due to its hemodynamic effects and to metabolic substrate shift induced by the mild and persistent hyperketonemia, while the positive effects of liraglutide treatment may be attributable to biologic changes of atherosclerotic lesions.

  2. Glucagon-like peptide-1 receptor agonists and risk of acute pancreatitis in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Cold, Frederik; Gluud, Lise L

    2017-01-01

    Glucagon-like peptide-1 receptor agonist (GLP-1RAs) labels warn about acute pancreatitis (AP) and impose upon doctors the obligation to inform patients about symptoms of AP. Here we systematically reviewed the risk of AP in randomized placebo-controlled trials (RCTs) investigating the effect of GLP......-1RAs in type 2 diabetes. We performed a systematic review with meta-analysis of long-term (minimum 24 months), placebo-controlled GLP-1RA RCTs in which AP was a predefined adverse event and adjudicated by blinded and independent adjudicating committees. Three high-quality RCTs included a total...... of 9347 GLP-1RA-treated and 9353 placebo-treated patients with type 2 diabetes. Compared to placebo, treatment with GLP1-RA was not associated with increased risk of AP (Peto odds ratio 0.745 [95% CI, 0.47-1.17]). Trial Sequential Analysis suggested that additional evidence is needed. In conclusion...

  3. No advantage of cell-penetrating peptides over receptor-specific antibodies in targeting antigen to human dendritic cells for cross-presentation.

    Science.gov (United States)

    Tacken, Paul J; Joosten, Ben; Reddy, Anita; Wu, Dayang; Eek, Annemarie; Laverman, Peter; Kretz-Rommel, Anke; Adema, Gosse J; Torensma, Ruurd; Figdor, Carl G

    2008-06-01

    Induction of CTL responses by dendritic cell (DC)-based vaccines requires efficient DC-loading strategies for class I Ags. Coupling Ags to cell-penetrating peptides (CPPs) or receptor-specific Abs improves Ag loading of DCs. In contrast to CPPs, receptor-specific Abs deliver conjugated Ags to DCs with high specificity, which is advantageous for in vivo strategies. It has, however, been speculated that CPPs facilitate uptake and endosomal escape of conjugated Ags, which would potently enhance cross-presentation. In this study, we directly compare the in vitro targeting efficiency of a humanized D1 Ab directed against the human DC surface receptor DC-SIGN hD1 to that of three CPPs. The three CPPs colocalized within endosomes when targeted to human monocyte-derived DCs simultaneously, whereas hD1 was present in a different set of endosomes. However, within 75 min after uptake CPPs and hD1 colocalized extensively within the lysosomal compartment. Ab-mediated targeting of class I-restricted peptides to DC-SIGN enhanced cross-presentation of the peptides, while only one of the CPPs enhanced peptide presentation. This CPP and hD1 enhanced cross-presentation with equal efficiencies. Thus, we found no evidence of CPP specifically favoring the delivery of conjugated Ag to the DC class I presentation pathway. Given the specificity with which Abs recognize their targets, this favors the use of DC receptor-specific Abs for in vivo vaccination strategies.

  4. Deterioration of kidney function by the (pro)renin receptor blocker handle region peptide in aliskiren-treated diabetic transgenic (mRen2)27 rats

    NARCIS (Netherlands)

    L. te Riet (Luuk); M.M. van den Heuvel (Mieke); C.J. Peutz-Kootstra (Carine); J.H.M. Esch, van (Joep); R. van Veghel (Richard); I.M. Garrelds (Ingrid); U. Musterd-Bhaggoe (Usha); A.M.B. Bouhuizen (Angelique); F.P.J. Leijten (Frank); A.H.J. Danser (Jan); W.W. Batenburg (Wendy)

    2014-01-01

    textabstractDual renin-angiotensin system (RAS) blockade in diabetic nephropathy is no longer feasible because of the profit/side effect imbalance. (Pro)renin receptor [(P)RR] blockade with handle region peptide (HRP) has been reported to exert beneficial effects in various diabetic models in a

  5. The T-Cell Receptor Can Bind to the Peptide-Bound Major Histocompatibility Complex and Uncomplexed β2-Microglobulin through Distinct Binding Sites

    DEFF Research Database (Denmark)

    Merkle, Patrick S; Irving, Melita; Hongjian, Song

    2017-01-01

    T-Cell receptor (TCR)-mediated recognition of the peptide-bound major histocompatibility complex (pMHC) initiates an adaptive immune response against antigen-presenting target cells. The recognition events take place at the TCR-pMHC interface, and their effects on TCR conformation and dynamics...

  6. A peptide antagonist of ErbB receptors, Inherbin3, induces neurite outgrowth from rat cerebellar granule neurons through ErbB1 inhibition

    DEFF Research Database (Denmark)

    Xu, Ruodan; Pankratova, Stanislava; Christiansen, Søren Hofman

    2013-01-01

    ErbB receptors not only function in cancer, but are also key developmental regulators in the nervous system. We previously identified an ErbB1 peptide antagonist, Inherbin3, that is capable of inhibiting tumor growth in vitro and in vivo. In this study, we found that inhibition of ErbB1 kinase ac...

  7. Peptide receptor radionuclide therapy in the management of gastrointestinal neuroendocrine tumors: efficacy profile, safety, and quality of life

    Directory of Open Access Journals (Sweden)

    Severi S

    2017-01-01

    Full Text Available Stefano Severi,1 Ilaria Grassi,1 Silvia Nicolini,1 Maddalena Sansovini,1 Alberto Bongiovanni,2 Giovanni Paganelli1 1Nuclear Medicine Unit, 2Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST IRCCS, Meldola, Italy Abstract: Peptide receptor radionuclide therapy (PRRT, developed over the last two decades, is carried out using radiopharmaceuticals such as 90Y-DOTA-Tyr3-octreotide and 177Lu-DOTA-Tyr3-octreotate (177Lu-Dotatate. These radiocompounds are obtained by labeling a synthetic somatostatin analog with a β-emitting radioisotope. The compounds differ from each other in terms of their energetic features (due to the radionuclide and peptide receptor affinity (due to the analog but share the common characteristic of binding specific membrane somatostatin receptors that are (generally overexpressed in neuroendocrine neoplasms (NENs and their metastases. NENs are tumors arising from diffuse neuroendocrine system cells that are classified according to grading based on Ki67 percentage values (Grades 1 and 2 are classed as neuroendocrine tumors [NETs] and to the anatomical site of occurrence (in this paper, we only deal with gastroenteropancreatic [GEP]-NETs, which account for 60%–70% of all NENs. They are also characterized by specific symptoms such as diarrhea and flushing (30% of cases. Despite substantial experience gained in the area of PRRT and its demonstrable effects in terms of efficacy, safety, and improvement in quality of life, these compounds are still not registered (registration of 177Lu-Dotatate for the treatment of midgut NETs is expected soon. Thus, PRRT can only be used in experimental protocols. We provide an overview of the work of leading groups with wide-ranging experience and continuity in data publication in the area of GEP-NET PRRT and report our own personal experience of using different dosage schedules based on the presence of kidney and bone marrow risk factors

  8. Design, synthesis, and validation of a β-turn mimetic library targeting protein-protein and peptide-receptor interactions.

    Science.gov (United States)

    Whitby, Landon R; Ando, Yoshio; Setola, Vincent; Vogt, Peter K; Roth, Bryan L; Boger, Dale L

    2011-07-06

    The design and synthesis of a β-turn mimetic library as a key component of a small-molecule library targeting the major recognition motifs involved in protein-protein interactions is described. Analysis of a geometric characterization of 10,245 β-turns in the protein data bank (PDB) suggested that trans-pyrrolidine-3,4-dicarboxamide could serve as an effective and synthetically accessible library template. This was confirmed by initially screening select compounds against a series of peptide-activated GPCRs that recognize a β-turn structure in their endogenous ligands. This validation study was highlighted by identification of both nonbasic and basic small molecules with high affinities (K(i) = 390 and 23 nM, respectively) for the κ-opioid receptor (KOR). Consistent with the screening capabilities of collaborators and following the design validation, the complete library was assembled as 210 mixtures of 20 compounds, providing a total of 4200 compounds designed to mimic all possible permutations of 3 of the 4 residues in a naturally occurring β-turn. Unique to the design and because of the C(2) symmetry of the template, a typical 20 × 20 × 20-mix (8000 compounds prepared as 400 mixtures of 20 compounds) needed to represent 20 variations in the side chains of three amino acid residues reduces to a 210 × 20-mix, thereby simplifying the library synthesis and subsequent screening. The library was prepared using a solution-phase synthetic protocol with liquid-liquid or liquid-solid extractions for purification and conducted on a scale that insures its long-term availability for screening campaigns. Screening the library against the human opioid receptors (KOR, MOR, and DOR) identified not only the activity of library members expected to mimic the opioid receptor peptide ligands but also additional side-chain combinations that provided enhanced receptor binding selectivities (>100-fold) and affinities (as low as K(i) = 80 nM for KOR). A key insight to emerge from

  9. Evolutionary divergence of the plant elicitor peptides (Peps) and their receptors: interfamily incompatibility of perception but compatibility of downstream signalling

    KAUST Repository

    Lori, M.

    2015-05-22

    Plant elicitor peptides (Peps) are potent inducers of pattern-triggered immunity and amplify the immune response against diverse pathogens. Peps have been discovered and studied extensively in Arabidopsis and only recently orthologs in maize were also identified and characterized in more detail. Here, the presence of PROPEPs, the Pep precursors, and PEPRs, the Pep receptors, was investigated within the plant kingdom. PROPEPs and PEPRs were identified in most sequenced species of the angiosperms. The conservation and compatibility of the Pep-PEPR-system was analysed by using plants of two distantly related dicot families, Brassicaceae and Solanaceae, and a representative family of monocot plants, the Poaceae. All three plant families contain important crop plants, including maize, rice, tomato, potato, and canola. Peps were not recognized by species outside of their plant family of origin, apparently because of a divergence of the Pep sequences. Three family-specific Pep motifs were defined and the integration of such a motif into the Pep sequence of an unrelated Pep enabled its perception. Transient transformation of Nicotiana benthamiana with the coding sequences of the AtPEPR1 and ZmPEPR1a led to the recognition of Pep peptides of Brassicaceae or Poaceae origin, respectively, and to the proper activation of downstream signalling. It was concluded that signalling machinery downstream of the PEPRs is highly conserved whereas the leucine-rich repeat domains of the PEPRs co-evolved with the Peps, leading to distinct motifs and, with it, interfamily incompatibility.

  10. ANP-mediated inhibition of distal nephron fractional sodium reabsorption in wild-type and mice overexpressing natriuretic peptide receptor.

    Science.gov (United States)

    Zhao, Di; Pandey, Kailash N; Navar, L Gabriel

    2010-01-01

    Atrial natriuretic peptide (ANP) elicits natriuresis; however, the relative contributions of proximal and distal nephron segments to the overall ANP-induced natriuresis have remained uncertain. This study was performed to characterize the effects of ANP on distal nephron sodium reabsorption determined after blockade of the two major distal nephron sodium transporters with amiloride (5 microg/g body wt) plus bendroflumethiazide (12 microg/g body wt) in male anesthetized C57/BL6 and natriuretic peptide receptor-A gene (Npr1) targeted four-copy mice. The lower dose of ANP (0.1 ng x g body wt(-1) x min(-1), n = 6) increased distal sodium delivery (DSD, 2.4 +/- 0.4 vs. 1.6 +/- 0.2 mueq/min, P 0.05), thus limiting the magnitude of the natriuresis. In contrast, the higher dose (0.2 ng x g body wt(-1) x min(-1), n = 6) increased DSD (2.8 +/- 0.3 mueq/min, P ANP increased urinary sodium excretion (0.6 +/- 0.1 vs. 0.3 +/- 0.1 mueq/min, P 0.05). These results provide in vivo evidence that ANP-mediated increases in DSD alone exert modest effects on sodium excretion and that inhibition of fractional reabsorption of distal sodium delivery is requisite for the augmented natriuresis in response to the higher dose of ANP or in Npr1 gene-duplicated mice.

  11. Effects of glucagon-like peptide-1 receptor agonists on non-alcoholic fatty liver disease and inflammation.

    Science.gov (United States)

    Wang, Xing-Chun; Gusdon, Aaron M; Liu, Huan; Qu, Shen

    2014-10-28

    Glucagon-like peptide1 (GLP-1) is secreted from Langerhans cells in response to oral nutrient intake. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new class of incretin-based anti-diabetic drugs. They function to stimulate insulin secretion while suppressing glucagon secretion. GLP-1-based therapies are now well established in the management of type 2 diabetes mellitus (T2DM), and recent literature has suggested potential applications of these drugs in the treatment of obesity and for protection against cardiovascular and neurological diseases. As we know, along with change in lifestyles, the prevalence of non-alcoholic fatty liver disease (NAFLD) in China is rising more than that of viral hepatitis and alcoholic fatty liver disease, and NAFLD has become the most common chronic liver disease in recent years. Recent studies further suggest that GLP-1RAs can reduce transaminase levels to improve NAFLD by improving blood lipid levels, cutting down the fat content to promote fat redistribution, directly decreasing fatty degeneration of the liver, reducing the degree of liver fibrosis and improving inflammation. This review shows the NAFLD-associated effects of GLP-1RAs in animal models and in patients with T2DM or obesity who are participants in clinical trials.

  12. A peptide derived from the CD loop-D helix region of ciliary neurotrophic factor (CNTF) induces neuronal differentiation and survival by binding to the leukemia inhibitory factor (LIF) receptor and common cytokine receptor chain gp130

    DEFF Research Database (Denmark)

    Rathje, Mette; Pankratova, Stanislava; Nielsen, Janne

    2011-01-01

    Ciliary neurotrophic factor (CNTF) induces neuronal differentiation and promotes the survival of various neuronal cell types by binding to a receptor complex formed by CNTF receptor a (CNTFRa), gp130, and the leukemia inhibitory factor (LIF) receptor (LIFR). The CD loop-D helix region of CNTF has...... that these receptors are involved in the effects of cintrofin. The C-terminal part of the peptide, corresponding to the D helix region of CNTF, was shown to be essential for the neuritogenic action of the peptide. CNTF and LIF induced neurite outgrowth in CGNs plated on laminin-coated slides. On uncoated slides, CNTF...... similar to those induced by CNTF and may be a valuable survival agent with possible therapeutic potential....

  13. Binding sites for. alpha. -bungarotoxin and the noncompetitive inhibitor phencyclidine on a synthetic peptide comprising residues 172-227 of the. alpha. -subunit of the nicotinic acetylcholine receptor

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly-Roberts, D.L.; Lentz, T.L. (Yale Univ., New Haven, CT (United States))

    1991-07-30

    The binding of the competitive antagonist {alpha}-bungarotoxin ({alpha}-Btx) and the noncompetitive inhibitor phencyclidine (PCP) to a synthetic peptide comprising residues 172-227 of the {alpha}-subunit of the Torpedo acetylcholine receptor has been characterized. {sup 125}I-{alpha}-Btx bound to the 172-227 peptide in a solid-phase assay and was competed by {alpha}-Btx d-tubocurarine and NaCl. In the presence of 0.02% sodium dodecyl sulfate, {sup 125}I-{alpha}-Btx bound to the 56-residue peptide with a K{sub D} of 3.5 nM, as determined by equilibrium saturation binding studies. Because {alpha}Btx binds to a peptide comprising residues 173-204 with the same affinity and does not bind to a peptide comprising residues 205-227, the competitive antagonist and hence agonist binding site lies between residues 173 and 204. After photoaffinity labeling, ({sup 3}H)PCP was bound to the 172-227 peptide. ({sup 3}H)PCP binding was inhibited by chlorpromazine, tetracaine, and dibucaine. It is concluded that a high-affinity binding site for PCP is located between residues 205 and 227, which includes the first 18 residues of transmembrane segment M1, and that a low-affinity site is located in the competitive antagonist binding site between residues 173 and 204. These results show that a synthetic peptide comprising residues 172-227 of the {alpha} subunit contains three binding sites, one for {alpha}-Btx and two for PCP. Previous studies on the intact receptor indicate high-affinity PCP binding occurs in the receptor channel.

  14. Distinctions between non-peptide angiotensin II AT1-receptor antagonists

    Directory of Open Access Journals (Sweden)

    Georges Vauquelin

    2001-03-01

    Full Text Available A far-reaching understanding of the molecular action mechanism of AT1-receptor antagonists (AIIAs was obtained by using CHO cells expressing transfected human AT 1-receptors. In this model, direct [3H]-antagonist binding and inhibition of agonist-induced responses (inositol phosphate accumulation can be measured under identical experimental conditions. Whereas preincubation with a surmountable AIIA (losartan causes parallel shifts of the angiotensin II (Ang II concentration-response curve, insurmountable antagonists also cause partial (i.e., 30% for irbesartan, 50% for valsartan, 70% for EXP3174, to almost complete (95% for candesartan reductions of the maximal response. The main conclusions are that all investigated antagonists are competitive with respect to Ang II. They bind to a common or overlapping site on the receptor in a mutually exclusive way. Insurmountable inhibition is related to the slow dissociation rate of the antagonist-receptor complex (t 1/2 of 7 minutes for irbesartan, 17 minutes for valsartan, 30 minutes for EXP3174 and 120 minutes for candesartan. Antagonist-bound AT1-receptors can adopt a fast and a slow reversible state. This is responsible for the partial nature of the insurmountable inhibition. The long-lasting effect of candesartan, the active metabolite of candesartan cilexetil, in vascular smooth muscle contraction studies, as well as in in vivo experiments on rat and in clinical studies, is compatible with its slow dissociation from, and continuous recycling between AT1-receptors. This recycling, or `rebinding' takes place because of the very high affinity of candesartan for the AT1-receptor.

  15. Identification of the bacteria-binding peptide domain on salivary agglutinin (gp-340/DMBT1), a member of the scavenger receptor cysteine-rich superfamily

    DEFF Research Database (Denmark)

    Bikker, Floris J; Ligtenberg, Antoon J M; Nazmi, Kamran

    2002-01-01

    Salivary agglutinin is encoded by DMBT1 and identical to gp-340, a member of the scavenger receptor cysteine-rich (SRCR) superfamily. Salivary agglutinin/DMBT1 is known for its Streptococcus mutans agglutinating properties. This 300-400 kDa glycoprotein is composed of conserved peptide motifs: 14...... SRCR domains that are separated by SRCR-interspersed domains (SIDs), 2 CUB (C1r/C1s Uegf Bmp1) domains, and a zona pellucida domain. We have searched for the peptide domains of agglutinin/DMBT1 responsible for bacteria binding. Digestion with endoproteinase Lys-C resulted in a protein fragment....... Strikingly, this peptide was also able to induce agglutination of S. mutans and a number of other bacteria. The repeated presence of this peptide in the native molecule endows agglutinin/DMBT1 with a general bacterial binding feature with a multivalent character. Moreover, our studies demonstrate...

  16. Electroacupuncture-Induced Dynamic Processes of Gene Expression Levels of Endogenous Opioid Peptide Precursors and Opioid Receptors in the CNS of Goats

    Directory of Open Access Journals (Sweden)

    Li-Li Cheng

    2013-01-01

    Full Text Available In order to investigate the dynamic processes of mRNA levels of proenkephalin, proopiomelanocortin, prodynorphin, and opioid receptors (δ-, μ-, and κ-receptor induced by electroacupuncture (EA in the central nerve system, goats were stimulated by EA of 60 Hz for 0.5 h at a set of Baihui, Santai, Ergen, and Sanyangluo points. The pain threshold was measured using the method of potassium iontophoresis. The mRNA levels of the three opioid peptide precursors and three opioid receptors were determined with quantitative real-time PCR and the levels of Met-enkephalin with SABC immunohistochemistry at 0.5 h before and at 0, 2, 4, 6, 8, 12, and 24 h after EA. The results showed that the pain threshold correlated (P<0.01 with Met-enkephalin immunoactivities in the measured nuclei and areas of goats. The analgesic aftereffect lasted for 12 h at least. The mRNA levels of the three opioid peptide precursors and three opioid receptors began to increase at 0 h, reached the peak during the time from 4 h to 6 h or at 12 h, and remained higher at 24 h after EA was discontinued. These results suggested that the initiation of gene expression of opioid peptides and the three receptors may be associated with EA-induced analgesic aftereffect.

  17. Amyloid Beta Peptides Block New Synapse Assembly by Nogo Receptor-Mediated Inhibition of T-Type Calcium Channels.

    Science.gov (United States)

    Zhao, Yanjun; Sivaji, Sivaprakash; Chiang, Michael C; Ali, Haadi; Zukowski, Monica; Ali, Sareen; Kennedy, Bryan; Sklyar, Alex; Cheng, Alice; Guo, Zihan; Reed, Alexander K; Kodali, Ravindra; Borowski, Jennifer; Frost, Georgia; Beukema, Patrick; Wills, Zachary P

    2017-10-11

    Compelling evidence links amyloid beta (Aβ) peptide accumulation in the brains of Alzheimer's disease (AD) patients with the emergence of learning and memory deficits, yet a clear understanding of the events that drive this synaptic pathology are lacking. We present evidence that neurons exposed to Aβ are unable to form new synapses, resulting in learning deficits in vivo. We demonstrate the Nogo receptor family (NgR1-3) acts as Aβ receptors mediating an inhibition of synapse assembly, plasticity, and learning. Live imaging studies reveal Aβ activates NgRs on the dendritic shaft of neurons, triggering an inhibition of calcium signaling. We define T-type calcium channels as a target of Aβ-NgR signaling, mediating Aβ's inhibitory effects on calcium, synapse assembly, plasticity, and learning. These studies highlight deficits in new synapse assembly as a potential initiator of cognitive pathology in AD, and pinpoint calcium dysregulation mediated by NgRs and T-type channels as key components. VIDEO ABSTRACT. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Design, synthesis, and functionalization of dimeric peptides targeting chemokine receptor CXCR4.

    NARCIS (Netherlands)

    Demmer, O.; Dijkgraaf, I.; Schumacher, U.; Marinelli, L.; Cosconati, S.; Gourni, E.; Wester, H.J.; Kessler, H.

    2011-01-01

    The chemokine receptor CXCR4 is a critical regulator of inflammation and immune surveillance, and it is specifically implicated in cancer metastasis and HIV-1 infection. On the basis of the observation that several of the known antagonists remarkably share a C(2) symmetry element, we constructed

  19. Polymorphism of glucagon-like peptide-1 receptor gene (rs1042044 ...

    African Journals Online (AJOL)

    patience

    2015-02-16

    Feb 16, 2015 ... turnover via GLP-1 receptors (GLP1Rs) in postmenopausal state. Furthermore, polymorphisms in. GLP1R gene were suggested to affect the function of GLP1Rs and be associated with many diseases. However, the relationships between GLP1R polymorphisms and osteoporosis susceptibility and bone.

  20. A novel glucagon-like peptide-1 (GLP-1)/glucagon hybrid peptide with triple-acting agonist activity at glucose-dependent insulinotropic polypeptide, GLP-1, and glucagon receptors and therapeutic potential in high fat-fed mice.

    Science.gov (United States)

    Gault, Victor A; Bhat, Vikas K; Irwin, Nigel; Flatt, Peter R

    2013-12-06

    Glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon bind to related members of the same receptor superfamily and exert important effects on glucose homeostasis, insulin secretion, and energy regulation. The present study assessed the biological actions and therapeutic utility of novel GIP/glucagon/GLP-1 hybrid peptides. Nine novel peptides were synthesized and exhibited complete DPP-IV resistance and enhanced in vitro insulin secretion. The most promising peptide, [dA(2)]GLP-1/GcG, stimulated cAMP production in GIP, GLP-1, and glucagon receptor-transfected cells. Acute administration of [dA(2)]GLP-1/GcG in combination with glucose significantly lowered plasma glucose and increased plasma insulin in normal and obese diabetic (ob/ob) mice. Furthermore, [dA(2)]GLP-1/GcG elicited a protracted glucose-lowering and insulinotropic effect in high fat-fed mice. Twice daily administration of [dA(2)]GLP-1/GcG for 21 days decreased body weight and nonfasting plasma glucose and increased circulating plasma insulin concentrations in high fat-fed mice. Furthermore, [dA(2)]GLP-1/GcG significantly improved glucose tolerance and insulin sensitivity by day 21. Interestingly, locomotor activity was increased in [dA(2)]GLP-1/GcG mice, without appreciable changes in aspects of metabolic rate. Studies in knock-out mice confirmed the biological action of [dA(2)]GLP-1/GcG via multiple targets including GIP, GLP-1, and glucagon receptors. The data suggest significant promise for novel triple-acting hybrid peptides as therapeutic options for obesity and diabetes.

  1. Activation of Relaxin Family Receptor 1 from different mammalian species by relaxin peptide and small molecule agonist ML290

    Directory of Open Access Journals (Sweden)

    Zaohua eHuang

    2015-08-01

    Full Text Available Relaxin peptide (RLN, which signals through the relaxin family peptide 1 (RXFP1 GPCR receptor, has shown therapeutic effects in an acute heart failure clinical trial. We have identified a small molecule agonist of human RXFP1, ML290; however, it does not activate the mouse receptor. To find a suitable animal model for ML290 testing and to gain mechanistic insights into the interaction of various ligands with RXFP1, we have cloned rhesus macaque, pig, rabbit, and guinea pig RXFP1s and analyzed their activation by RLN and ML290. HEK293T cells expressing macaque or pig RXFP1 responded to relaxin and ML290 treatment as measured by an increase of cAMP production. Guinea pig RXFP1 responded to relaxin but had very low response to ML290 treatment only at highest concentrations used. The rabbit RXFP1 amino acid sequence was the most divergent, with a number of unique substitutions within the ectodomain and the 7-transmembrane domain (7TM. Two splice variants of rabbit RXFP1 derived through alternative splicing of the forth exon were identified. In contrast to the other species, rabbit RXFP1s were activated by ML290, but not with human, pig, mouse, or rabbit relaxins. Using FLAG-tagged constructs, we have shown that both rabbit RXFP1 variants are expressed on the cell surface. No binding of human Eu-labeled relaxin to rabbit RXFP1 was detected, suggesting that in this species RXFP1 might be non-functional. We used chimeric rabbit-human and guinea pig-human constructs to identify regions important for RLN or ML290 receptor activation. Chimeras with the human ectodomain and rabbit 7TM domain were activated by RLN, whereas substitution of part of the guinea pig 7TM domain with the human sequence only partially restored ML290 activation, confirming the allosteric mode of action for the two ligands. Our data demonstrate that macaque and pig models can be used for ML290 testing.

  2. Natural Compounds Interacting with Nicotinic Acetylcholine Receptors: From Low-Molecular Weight Ones to Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Denis Kudryavtsev

    2015-05-01

    Full Text Available Nicotinic acetylcholine receptors (nAChRs fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt, and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds.

  3. Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence.

    Science.gov (United States)

    Kumpf, Robert P; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J; Aalen, Reidunn B

    2013-03-26

    Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LIKE2 (HSL2). Emergence of new lateral root primordia, initiated deep inside the root under the influence of auxin, is similarly dependent on cell wall dissolution between cells in the overlaying endodermal, cortical, and epidermal tissues. Here we show that this process requires IDA, HAE, and HSL2. Mutation in these genes constrains the passage of the growing lateral root primordia through the overlaying layers, resulting in altered shapes of the lateral root primordia and of the overlaying cells. The HAE and HSL2 receptors are redundant in function during floral organ abscission, but during lateral root emergence they are differentially involved in regulating cell wall remodeling genes. In the root, IDA is strongly auxin-inducible and dependent on key regulators of lateral root emergence--the auxin influx carrier LIKE AUX1-3 and AUXIN RESPONSE FACTOR7. The expression levels of the receptor genes are only transiently induced by auxin, suggesting they are limiting factors for cell separation. We conclude that elements of the same cell separation signaling module have been adapted to function in different developmental programs.

  4. Structural requirements for the action of parathyroid hormone-related protein (PTHrP) on bone resorption by isolated osteoclasts

    Energy Technology Data Exchange (ETDEWEB)

    Evely, R.S.; Bonomo, A.; Schneider, H.G.; Moseley, J.M.; Gallagher, J.; Martin, T.J. (St. Vincent' s Institute of Medical Research, Melbourne (Australia))

    1991-01-01

    Parathyroid hormone-related protein (PTHrP) plays a major role in the syndrome of humoral hypercalcemia of malignancy (HHM) by its actions on bone and kidney. In this study an isolated osteoclast bone resorption assay was used to investigate the actions of this peptide and the structure-activity relationships for its resorption effect. As with PTH, neither synthetic nor recombinant PTHrP preparations stimulated resorption within highly purified osteoclast populations. Resorption was stimulated only in the presence of contaminating osteoblasts or in cocultures with the osteoblast-like cell line UMR-106. In the presence of osteoblasts PTHrP-(1-34) and PTHrP-(1-84) stimulated bone resorption in a dose-dependent manner with a potency comparable to that of PTH-(1-34) on a molar basis. The biologic activity of the PTHrP was shown to reside in the first 34 amino acids, and within that region the structural requirements for promotion of osteoclastic resorption resembled closely those for promotion of cyclic AMP formation in osteoblast-like cells. Using emulsion autoradiography with iodinated PTHrP-(1-34) and PTHrP-(1-84) on mixed bone cell preparations from neonatal rats, specific binding was demonstrated only to osteoblasts, not to osteoclasts. These results clearly demonstrate that PTHrP is a potent stimulator of bone resorption and that these effects are, like those of PTH, mediated by initial actions upon cells of the osteoblast lineage.

  5. A convenient method for europium-labeling of a recombinant chimeric relaxin family peptide R3/I5 for receptor-binding assays.

    Science.gov (United States)

    Zhang, Wei-Jie; Jiang, Qian; Wang, Xin-Yi; Song, Ge; Shao, Xiao-Xia; Guo, Zhan-Yun

    2013-06-01

    Relaxin family peptides have important biological functions, and so far, four G-protein-coupled receptors have been identified as their receptors (RXFP1-4). A chimeric relaxin family peptide R3/I5, containing the B-chain of relaxin-3 and the A-chain of INSL5, is a selective agonist for both RXFP3 and RXFP4. In a previous study, europium-labeled R3/I5, as a nonradioactive and low-background receptor-binding tracer, was prepared through a chemical synthesis approach. In the present study, we established a convenient alternative approach for preparing the europium-labeled R3/I5 tracer based on a recombinant R3/I5 designed to carry a solubilizing tag at the A-chain N-terminus and a pyroglutamate residue at the B-chain N-terminus. Because of the presence of a single primary amine moiety, the recombinant R3/I5 peptide was site-specifically mono-labeled at the A-chain N-terminus by a diethylenetriaminepentaacetic acid/europium moiety through a convenient one-step procedure. The diethylenetriaminepentaacetic acid/Eu3+-labeled R3/I5 bound both receptors RXFP3 and RXFP4 with high binding affinities and low nonspecific binding. Thus, we have presented a valuable nonradioactive tracer for future interaction studies on RXFP3 and RXFP4 with various natural or designed ligands. The present approach could also be adapted for preparing and labeling of other chimeric relaxin family peptides. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.

  6. Curcumin induces human cathelicidin antimicrobial peptide gene expression through a vitamin D receptor-independent pathway

    DEFF Research Database (Denmark)

    Guo, Chunxiao; Rosoha, Elena; Lowry, Malcolm B

    2013-01-01

    The vitamin D receptor (VDR) mediates the pleiotropic biologic effects of 1α,25 dihydroxy-vitamin D(3). Recent in vitro studies suggested that curcumin and polyunsaturated fatty acids (PUFAs) also bind to VDR with low affinity. As potential ligands for the VDR, we hypothesized that curcumin...... cancer cell line HT-29 and keratinocyte cell line HaCaT. We demonstrated that PUFAs failed to induce CAMP or CYP24A1 mRNA expression in all three cell lines, but curcumin up-regulated CAMP mRNA and protein levels in U937 cells. Curcumin treatment induced CAMP promoter activity from a luciferase reporter...... construct lacking the VDR binding site and did not increase binding of the VDR to the CAMP promoter as determined by chromatin immunoprecipitation assays. These findings indicate that induction of CAMP by curcumin occurs through a vitamin D receptor-independent manner. We conclude that PUFAs and curcumin do...

  7. Differential expression patterns of PQRFamide peptide and its two receptor genes in the brain and pituitary of grass puffer during the reproductive cycle.

    Science.gov (United States)

    Shahjahan, Md; Doi, Hiroyuki; Ando, Hironori

    2015-01-01

    Pain-modulatory neuropeptides, PQRFamide (PQRFa) peptides, have recently been implicated in the regulation of reproduction in fish. As a first step toward investigating the role of PQRFa peptides on reproductive function in the grass puffer Takifugu niphobles, which is a semilunar spawner, we cloned genes encoding PQRFa peptide precursor (pqrfa) and its two types of receptors (pqrfa-r1 and pqrfa-r2), and examined changes in their expression levels in the brain and pituitary over several months during the reproductive cycle. The grass puffer PQRFa peptide precursor of 126 amino acid residues contains two putative PQRFa peptides, PQRFa-1 and PQRFa-2, which correspond to NPFF and NPAF in other vertebrates, respectively. The grass puffer PQRFa-R1 and PQRFa-R2 consist of 426 and 453 amino acid residues, respectively, and contain distinct characteristics of G-protein coupled receptors. These three genes were exclusively expressed in the brain and pituitary. The expression levels of pqrfa and pqrfa-r1 were significantly increased during the late stage of sexual maturation, but low in the spawning fish just after releasing sperms and eggs. Therefore, the grass puffer PQRFa peptide may have a role in the late stage of sexual maturation before spawning via PQRFa-R1. In contrast, the pqrfa-r2 expression showed maximum levels in the spawning fish and in the post-spawning period. The present results provide fundamental data suggesting that the grass puffer PQRFa peptide may have multiple roles in the control of reproduction that are dependent on the reproductive stages. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Synthesis, stabilization and formulation of [{sup 177}Lu]Lu-AMBA, a systemic radiotherapeutic agent for Gastrin Releasing Peptide receptor positive tumors

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jianqing [Bracco Research USA Inc., 305 College Road East, Princeton, NJ 08540 (United States); Linder, Karen E. [Bracco Research USA Inc., 305 College Road East, Princeton, NJ 08540 (United States)], E-mail: karen.linder@bru.bracco.com; Cagnolini, Aldo; Metcalfe, Edmund; Raju, Natarajan; Tweedle, Michael F.; Swenson, Rolf E. [Bracco Research USA Inc., 305 College Road East, Princeton, NJ 08540 (United States)

    2008-04-15

    A robust formulation was developed for [{sup 177}Lu]Lu-AMBA ({sup 177}Lu-DO3A-CH{sub 2}CO-G-[4-aminobenzoyl]-QWAVGHLM-NH{sub 2}), a Bombesin-like agonist with high affinity for Gastrin Releasing Peptide (GRP) receptors. During optimization of labeling, the effect of several radiostabilizers was evaluated; a combination of selenomethionine and ascorbic acid showed superiority over other tested radiostabilizers. The resulting two-vial formulation maintains a radiochemical purity (RCP) of >90% for at least 2 days at room temperature. The method of stabilization should be useful for other methionine-containing peptide radiopharmaceuticals in diagnostic and therapeutic applications.

  9. An NCAM-derived FGF-receptor agonist, the FGL-peptide, induces neurite outgrowth and neuronal survival in primary rat neurons

    DEFF Research Database (Denmark)

    Neiiendam, Johanne Louise; Køhler, Lene Boding; Christensen, Claus

    2004-01-01

    factor receptor (FGFR). NCAM-mediated adhesion leads to activation of various intracellular signal transduction pathways, including the Ras-mitogen activated protein kinase (MAPK) and the phosphatidylinositol-3-kinase (PI3K)-Akt pathways. A synthetic peptide derived from the second fibronectin type III...... of the FGL peptide are shown to depend on activation of FGFR and the MAPK and PI3K intracellular signalling pathways, all three kinases being necessary for the effects of FGL on neurite outgrowth and neuronal survival....

  10. Presence and function of the calcitonin gene-related peptide receptor on rat pial arteries investigated in vitro and in vivo

    DEFF Research Database (Denmark)

    Petersen, K A; Nilsson, E; Olesen, J

    2005-01-01

    Calcitonin gene-related peptide (CGRP) and related peptides may be involved in migraine pathogenesis. To understand their vasomotor role in the cerebral circulation, we performed two studies, a pressurized arteriography study of the middle cerebral artery (MCA) and a genuine closed cranial window......, this was probably secondary to a decrease in blood pressure of 44.8 +/- 3.3 mmHg and 49.2 +/- 3.3 mmHg. Our results suggest that CGRP receptors are probably functional on the smooth muscle cells and not on the endothelium of rat cerebral arteries....

  11. Comparison of three radiolabelled peptide analogues for CCK-2 receptor scintigraphy in medullary thyroid carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Froeberg, Alida C.; Jong, Marion de; Breeman, Wout A.P.; Verdijsseldonck, Marion; Kooij, Peter P.M. [Erasmus MC University Medical Center Rotterdam, Department of Nuclear Medicine, Rotterdam (Netherlands); Nock, Berthold A.; Maina, Theodosia [NCSR ' ' Demokritos' ' , Molecular Radiopharmacy, I/R-RP, Athens (Greece); Erion, Jack L. [BioSynthema Inc., St. Louis, MO (United States); Herder, Wouter W. de [Erasmus MC, Department of Internal Medicine, Rotterdam (Netherlands); Lugt, Aad van der [Erasmus MC, Department of Radiology, Rotterdam (Netherlands); Krenning, Eric P. [Erasmus MC University Medical Center Rotterdam, Department of Nuclear Medicine, Rotterdam (Netherlands); Erasmus MC, Department of Internal Medicine, Rotterdam (Netherlands)

    2009-08-15

    Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in a high percentage of medullary thyroid carcinomas (MTC). Analogous to somatostatin receptors, CCK-2 receptors might be viable targets for radionuclide scintigraphy and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed, and some have been carried through into clinical studies. However, these studies are mostly limited and difficult to compare. The aim of this study was to evaluate the diagnostic and therapeutic potential of three promising CCK-2 receptor-binding radiopeptides in patients with MTC. {sup 111}In-DOTA-(D)Asp-Tyr-Nle-Gly-Trp-Nle-Asp-Phe-NH{sub 2} ({sup 111}In-DOTA-CCK), a CCK analogue, and the gastrin-based ligands {sup 99m}Tc-N{sub 4}-Gly-(D)Glu-(Glu){sub 5}-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH{sub 2} ({sup 99m}Tc-demogastrin 2) and {sup 111}In-DOTA-(D)Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH{sub 2} ({sup 111}In-DOTA-MG11) were each administered to the same group of six patients. Planar images made at 3-5, 7 and 24 h p.i. were used for comparison of tumour visualisation and renal uptake. {sup 99m}Tc-demogastrin 2 scintigraphy visualised all known lesions and new lesions in four of six patients. {sup 111}In-DOTA-CCK and {sup 111}In-DOTA-MG11 on the other hand missed several lesions; tumour uptake of these two radiopharmaceuticals was quite low. Comparison of retention of renal activity showed no major differences between the three radiopeptides. {sup 99m}Tc-demogastrin 2 scintigraphy appeared most promising as a diagnostic tool in patients with MTC. Further studies are required to evaluate its value in patient management. Direct comparisons of the compounds studied strongly suggests that {sup 111}In-DOTA-CCK and {sup 111}In-DOTA-MG11 have less potential as imaging agents than {sup 99m}Tc-demogastrin 2. These DOTA-linked compounds are considered unlikely to be useful for radionuclide therapy because of low tumour uptake. (orig.)

  12. Wheat peptides reduce oxidative stress and inhibit NO production through modulating μ-opioid receptor in a rat NSAID-induced stomach damage model.

    Science.gov (United States)

    Yin, Hong; Cai, Hui-Zhen; Wang, Shao-Kang; Yang, Li-Gang; Sun, Gui-Ju

    2015-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) induce tissue damage and oxidative stress in animal models of stomach damage. In the present study, the protective effects of wheat peptides were evaluated in a NSAID-induced stomach damage model in rats. Different doses of wheat peptides or distilled water were administered daily by gavage for 30 days before the rat stomach damage model was established by administration of NSAIDs (aspirin and indomethacin) into the digestive tract twice. The treatment of wheat peptides decreased the NSAID-induced gastric epithelial cell degeneration and oxidative stress and NO levels in the rats. Wheat peptides significantly increased the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and decreased iNOS activity in stomach. The mRNA expression level of μ-opioid receptor was significantly decreased in wheat peptides-treated rats than that in in the control rats. The results suggest that NSAID drugs induced stomach damage in rats, wchih can be prevented by wheat peptides. The mechanisms for the protective effects were most likely through reducing NSAID-induced oxidative stress. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  13. Polyclonal Anti-Peptide Antibodies Against Both Activated and Unactivated Forms of the Human Glucocorticoid Receptor

    Science.gov (United States)

    1993-04-30

    milk and a 1:100, 1 : 500, or 1 : 1000 dilution of preimmune sera, polyclonal a n ti- huma n GR antisera AC40 . or test sera from rabbits 709. 710...8217.nti-hGR antisera were generated in three lle’’’’ Zealand vlhi tE: rabbits . Immunoabsorption of [ 3H ] tr i a n cinolone acetonide ([3HjTA) -labeled...et al . . 1986) . In addition, thi s superfamily includes a number of orphan receptors whose ligands have not been identified and i-lhose

  14. Positron emission tomography imaging of the glucagon-like peptide-1 receptor in healthy and streptozotocin-induced diabetic pigs

    Energy Technology Data Exchange (ETDEWEB)

    Nalin, Lovisa; Andreasson, Susanne; Wikstrand, Anna; Ryden, Anneli; Nyman, Goerel; Jensen-Waern, Marianne [Swedish University of Agricultural Sciences, Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Uppsala (Sweden); Selvaraju, Ram K.; Eriksson, Olof [Uppsala University, Department of Medicinal Chemistry, Preclinical PET Platform, Uppsala (Sweden); Velikyan, Irina [Uppsala University, Department of Medicinal Chemistry, Preclinical PET Platform, Uppsala (Sweden); Uppsala University, Department of Radiology, Oncology and Radiation Sciences, Uppsala (Sweden); Uppsala University Hospital, PET Centre, Centre for Medical Imaging, Uppsala (Sweden); Berglund, Marie [Uppsala University, Department of Medicinal Chemistry, Preclinical PET Platform, Uppsala (Sweden); Uppsala University, Department of Radiology, Oncology and Radiation Sciences, Uppsala (Sweden); Lubberink, Mark [Uppsala University, Department of Radiology, Oncology and Radiation Sciences, Uppsala (Sweden); Kandeel, Fouad [Beckman Research Institute of the City of Hope, Duarte, CA (United States); Korsgren, Olle [Uppsala University, Department of Immunology, Genetics and Pathology, Uppsala (Sweden)

    2014-09-15

    The glucagon-like peptide-1 receptor (GLP-1R) has been proposed as a target for molecular imaging of beta cells. The feasibility of non-invasive imaging and quantification of GLP-1R in pancreas using the positron emission tomography (PET) tracer [{sup 68}Ga]Ga-DO3A-VS-Cys{sup 40}-Exendin-4 in non-diabetic and streptozotocin (STZ)-induced diabetic pigs treated with insulin was investigated. Non-diabetic (n = 4) and STZ-induced diabetic pigs (n = 3) from the same litter were examined. Development of diabetes was confirmed by blood glucose values, clinical examinations and insulin staining of pancreatic sections post mortem. Tissue perfusion in the pancreas and kidneys was evaluated by [{sup 15}O]water PET/computed tomography (CT) scans. The in vivo receptor specificity of [{sup 68}Ga]Ga-DO3A-VS-Cys{sup 40}-Exendin-4 was assessed by administration of either tracer alone or by competition with 3-6.5 μg/kg of Exendin-4. Volume of distribution and occupancy in the pancreas were quantified with a single tissue compartment model. [{sup 15}O]water PET/CT examinations showed reduced perfusion in the pancreas and kidneys in diabetic pigs. [{sup 68}Ga]Ga-DO3A-VS-Cys{sup 40}-Exendin-4 uptake in the pancreas of both non-diabetic and diabetic pigs was almost completely abolished by co-injection of unlabeled Exendin-4 peptide. [{sup 68}Ga]Ga-DO3A-VS-Cys{sup 40}-Exendin-4 uptake did not differ between non-diabetic and diabetic pigs. In all animals, administration of the tracer resulted in an immediate increase in the heart rate (HR). Pancreatic uptake of [{sup 68}Ga]Ga-DO3A-VS-Cys{sup 40}-Exendin-4 was not reduced by destruction of beta cells in STZ-induced diabetic pigs. (orig.)

  15. X-ray Crystal Structures of Monomeric and Dimeric Peptide Inhibitors in Complex with the Human Neonatal Fc Receptor, FcRn

    Energy Technology Data Exchange (ETDEWEB)

    Mezo, Adam R.; Sridhar, Vandana; Badger, John; Sakorafas, Paul; Nienaber, Vicki (Zenobia); (Biogen)

    2010-10-28

    The neonatal Fc receptor, FcRn, is responsible for the long half-life of IgG molecules in vivo and is a potential therapeutic target for the treatment of autoimmune diseases. A family of peptides comprising the consensus motif GHFGGXY, where X is preferably a hydrophobic amino acid, was shown previously to inhibit the human IgG:human FcRn protein-protein interaction (Mezo, A. R., McDonnell, K. A., Tan Hehir, C. A., Low, S. C., Palombella, V. J., Stattel, J. M., Kamphaus, G. D., Fraley, C., Zhang, Y., Dumont, J. A., and Bitonti, A. J. (2008) Proc. Natl. Acad. Sci. U.S.A., 105, 2337-2342). Herein, the x-ray crystal structure of a representative monomeric peptide in complex with human FcRn was solved to 2.6 {angstrom} resolution. The structure shows that the peptide binds to human FcRn at the same general binding site as does the Fc domain of IgG. The data correlate well with structure-activity relationship data relating to how the peptide family binds to human FcRn. In addition, the x-ray crystal structure of a representative dimeric peptide in complex with human FcRn shows how the bivalent ligand can bridge two FcRn molecules, which may be relevant to the mechanism by which the dimeric peptides inhibit FcRn and increase IgG catabolism in vivo. Modeling of the peptide:FcRn structure as compared with available structural data on Fc and FcRn suggest that the His-6 and Phe-7 (peptide) partially mimic the interaction of His-310 and Ile-253 (Fc) in binding to FcRn, but using a different backbone topology.

  16. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors.

    Science.gov (United States)

    Culhane, Kelly J; Liu, Yuting; Cai, Yingying; Yan, Elsa C Y

    2015-01-01

    Although family B G protein-coupled receptors (GPCRs) contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs.

  17. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors

    Directory of Open Access Journals (Sweden)

    Kelly J Culhane

    2015-11-01

    Full Text Available Although family B G protein-coupled receptors (GPCRs contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs.

  18. Potent Body Weight-Lowering Effect of a Neuromedin U Receptor 2-selective PEGylated Peptide.

    Science.gov (United States)

    Kanematsu-Yamaki, Yoko; Nishizawa, Naoki; Kaisho, Tomoko; Nagai, Hiroaki; Mochida, Taisuke; Asakawa, Tomoko; Inooka, Hiroshi; Dote, Katsuko; Fujita, Hisashi; Matsumiya, Kouta; Hirabayashi, Hideki; Sakamoto, Junichi; Ohtaki, Tetsuya; Takekawa, Shiro; Asami, Taiji

    2017-07-27

    Neuromedin U (NMU) is a neuropeptide that mediates a variety of physiological functions via its receptors, NMUR1 and NMUR2. Recently, there has been an increased focus on NMU as a promising treatment option for diabetes and obesity. A short form of NMU (NMU-8) has potent agonist activity for both receptors but is metabolically unstable. Therefore, we designed and synthesized NMU-8 analogues modified by polyethylene glycol (PEG; molecular weight, 20 kDa; PEG20k) via a linker. 3-(2-Naphthyl)alanine substitution at position 19 increased NMUR2 selectivity of NMU-8 analogues with retention of high agonist activity. Compound 37, an NMUR2-selective PEG20k analogue containing piperazin-1-ylacetyl linker, exhibited a potent body weight-lowering effect with concomitant inhibition of food intake in a dose-dependent manner (body weight loss of 12.4% at 30 nmol/kg) by once-daily repeated dosing for 2 weeks in mice with diet-induced obesity.

  19. The Effect of Glucagon-Like Peptide-2 Receptor Agonists on Colonic Anastomotic Wound Healing

    Directory of Open Access Journals (Sweden)

    Heather A. Redstone

    2010-01-01

    Full Text Available Background. Glucagon-like peptide 2 (GLP-2 is an intestinal specific trophic hormone, with therapeutic potential; the effects on intestinal healing are unknown. We used a rat model of colonic healing, under normoxic, and stress (hypoxic conditions to examine the effect of GLP-2 on intestinal healing. Methods. Following colonic transection and reanastomosis, animals were randomized to one of six groups (n=8/group: controls, native GLP-2, long-acting GLP-2 (GLP-2- MIMETIBODY, GLP-2-MMB, animals were housed under normoxic or hypoxic (11%  O2 conditions. Animals were studied five days post-operation for anastomotic strength and wound characteristics. Results. Anastomotic bursting pressure was unchanged by GLP-2 or GLP-2-MMB in normoxic or hypoxic animals; both treatments increased crypt cell proliferation. Wound IL-1β increased with GLP-2; IFNγ with GLP-2 and GLP-2-MMB. IL-10 and TGF-β were decreased; Type I collagen mRNA expression increased in hypoxic animals while Type III collagen was reduced with both GLP-2 agonists. GLP-2 MMB, but not native GLP-2 increased TIMP 1-3 mRNA levels in hypoxia. Conclusions. The effects on CCP, cytokines and wound healing were similar for both GLP-2 agonists under normoxic and hypoxic conditions; anastomotic strength was not affected. This suggests that GLP-2 (or agonists could be safely used peri-operatively; direct studies will be required.

  20. Unravelling the Evolution of the Allatostatin-Type A, KISS and Galanin Peptide-Receptor Gene Families in Bilaterians: Insights from Anopheles Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Rute C Felix

    Full Text Available Allatostatin type A receptors (AST-ARs are a group of G-protein coupled receptors activated by members of the FGL-amide (AST-A peptide family that inhibit food intake and development in arthropods. Despite their physiological importance the evolution of the AST-A system is poorly described and relatively few receptors have been isolated and functionally characterised in insects. The present study provides a comprehensive analysis of the origin and comparative evolution of the AST-A system. To determine how evolution and feeding modified the function of AST-AR the duplicate receptors in Anopheles mosquitoes, were characterised. Phylogeny and gene synteny suggested that invertebrate AST-A receptors and peptide genes shared a common evolutionary origin with KISS/GAL receptors and ligands. AST-ARs and KISSR emerged from a common gene ancestor after the divergence of GALRs in the bilaterian genome. In arthropods, the AST-A system evolved through lineage-specific events and the maintenance of two receptors in the flies and mosquitoes (Diptera was the result of a gene duplication event. Speciation of Anopheles mosquitoes affected receptor gene organisation and characterisation of AST-AR duplicates (GPRALS1 and 2 revealed that in common with other insects, the mosquito receptors were activated by insect AST-A peptides and the iCa2+-signalling pathway was stimulated. GPRALS1 and 2 were expressed mainly in mosquito midgut and ovaries and transcript abundance of both receptors was modified by feeding. A blood meal strongly up-regulated expression of both GPRALS in the midgut (p < 0.05 compared to glucose fed females. Based on the results we hypothesise that the AST-A system in insects shared a common origin with the vertebrate KISS system and may also share a common function as an integrator of metabolism and reproduction.AST-A and KISS/GAL receptors and ligands shared common ancestry prior to the protostome-deuterostome divergence. Phylogeny and gene

  1. In Vitro and In Vivo Evaluation of Alexa Fluor 680-Bombesin[7–14]NH2 Peptide Conjugate, a High-Affinity Fluorescent Probe with High Selectivity for the Gastrin-Releasing Peptide Receptor

    Directory of Open Access Journals (Sweden)

    Lixin Ma

    2007-05-01

    Full Text Available Gastrin-releasing peptide (GRP receptors are overexpressed on several types of human cancer cells, including breast, prostate, small cell lung, and pancreatic cancers. Bombesin (BBN, a 14–amino acid peptide that is an analogue of human GRP, binds to GRP receptors with very high affinity and specificity. The aim of this study was to develop a new fluorescent probe based on BBN having high tumor uptake and optimal pharmacokinetics for specific targeting and optical imaging of human breast cancer tissue. In this study, solid-phase peptide synthesis was used to produce H2N-glycylglycylglycine-BBN[7–14]NH2 peptide with the following general sequence: H2N-G-G-G-Q-W-A-V-G-H-L-M-(NH2. This conjugate was purified by reversed-phase high-performance liquid chromatography and characterized by electrospray-ionization mass spectra. The fluorescent probe Alexa Fluor 680-G-G-G-BBN[7–14]NH2 conjugate was prepared by reaction of Alexa Fluor 680 succinimidyl ester to H2N-G-G-G-BBN[7–14]NH2 in dimethylformamide (DMF. In vitro competitive binding assays, using 125I-Tyr4-BBN as the radiolabeling gold standard, demonstrated an inhibitory concentration 50% value of 7.7 ± 1.4 nM in human T-47D breast cancer cells. Confocal fluorescence microscopy images of Alexa Fluor 680-G-G-G-BBN[7–14]NH2 in human T-47D breast cancer cells indicated specific uptake, internalization, and receptor blocking of the fluorescent bioprobe in vitro. In vivo investigations in SCID mice bearing xenografted T-47D breast cancer lesions demonstrated the ability of this new conjugate to specifically target tumor tissue with high selectivity and affinity.

  2. In vitro and in vivo evaluation of Alexa Fluor 680-bombesin[7-14]NH2 peptide conjugate, a high-affinity fluorescent probe with high selectivity for the gastrin-releasing peptide receptor.

    Science.gov (United States)

    Ma, Lixin; Yu, Ping; Veerendra, Bhadrasetty; Rold, Tammy L; Retzloff, Lauren; Prasanphanich, Adam; Sieckman, Gary; Hoffman, Timothy J; Volkert, Wynn A; Smith, Charles J

    2007-01-01

    Gastrin-releasing peptide (GRP) receptors are overexpressed on several types of human cancer cells, including breast, prostate, small cell lung, and pancreatic cancers. Bombesin (BBN), a 14-amino acid peptide that is an analogue of human GRP, binds to GRP receptors with very high affinity and specificity. The aim of this study was to develop a new fluorescent probe based on BBN having high tumor uptake and optimal pharmacokinetics for specific targeting and optical imaging of human breast cancer tissue. In this study, solid-phase peptide synthesis was used to produce H(2)N-glycylglycylglycine-BBN[7-14]NH(2) peptide with the following general sequence: H(2)N-G-G-G-Q-W-A-V-G-H-L-M-(NH(2)). This conjugate was purified by reversed-phase high-performance liquid chromatography and characterized by electrospray-ionization mass spectra. The fluorescent probe Alexa Fluor 680-G-G-G-BBN[7-14]NH(2) conjugate was prepared by reaction of Alexa Fluor 680 succinimidyl ester to H(2)N-G-G-G-BBN[7-14]NH(2) in dimethylformamide (DMF). In vitro competitive binding assays, using (125)I-Tyr(4)-BBN as the radiolabeling gold standard, demonstrated an inhibitory concentration 50% value of 7.7 +/- 1.4 nM in human T-47D breast cancer cells. Confocal fluorescence microscopy images of Alexa Fluor 680-G-G-G-BBN[7-14]NH(2) in human T-47D breast cancer cells indicated specific uptake, internalization, and receptor blocking of the fluorescent bioprobe in vitro. In vivo investigations in SCID mice bearing xenografted T-47D breast cancer lesions demonstrated the ability of this new conjugate to specifically target tumor tissue with high selectivity and affinity.

  3. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  4. The tumour sink effect on the biodistribution of {sup 68}Ga-DOTA-octreotate: implications for peptide receptor radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Beauregard, Jean-Mathieu [Peter MacCallum Cancer Centre and University of Melbourne, Centre for Cancer Imaging, Melbourne (Australia); Centre hospitalier universitaire de Quebec and Laval University, Molecular Imaging Research Group, Medical Imaging Department, Quebec City, QC (Canada); Hofman, Michael S.; Kong, Grace; Hicks, Rodney J. [Peter MacCallum Cancer Centre and University of Melbourne, Centre for Cancer Imaging, Melbourne (Australia)

    2012-01-15

    Tumour sequestration of radiotracer may lead to decreased bioavailability in healthy tissue resulting in lower absorbed radiation dose to critical organs. This study aims to assess the impact of disease burden, body habitus and urinary excretion on the biodistribution of {sup 68}Ga-DOTA-octreotate. Ten patients with highly varied burden of somatostatin receptor-positive neuroendocrine tumour on {sup 68}Ga-DOTA-octreotate positron emission tomography (PET)/CT were selected. Volumes of interest were drawn to derive the average uptake of renal parenchyma, spleen and body background, as well as to compute the fraction of injected activity sequestered in tumour and excreted in urine. Uptake values were assessed for correlation with tumour sequestration, weight, lean body weight, body surface area and urinary excretion. There was a trend for tumour sequestration, body habitus and urinary excretion to inversely influence all healthy tissue uptake values. In particular, renal uptake, splenic intensity and background soft tissue activity were all significantly correlated to composite factors combining tumour sequestration with body habitus and renal excretion. When combined with body habitus index or a body habitus index and renal excretion, tumour sequestration was strongly and significantly correlated inversely with renal uptake. Our results suggest that tumour sequestration of {sup 68}Ga-DOTA-octreotate is a major factor leading to a sink effect that decreases activity concentration in healthy organs such as the kidney. However, body habitus and renal function also influence tissue biodistribution, in a synergistic fashion. Compared with a fixed-dose peptide receptor radionuclide therapy protocol, an adjusted-dose regimen tailored to tumour burden, body habitus and renal function may allow greater radiation dose to individual lesions without substantially adding to toxicity in normal tissues. (orig.)

  5. Nonpeptide and peptide growth hormone secretagogues act both as ghrelin receptor agonist and as positive or negative allosteric modulators of ghrelin signaling

    DEFF Research Database (Denmark)

    Holst, Birgitte; Brandt, Erik; Bach, Anders

    2005-01-01

    Two nonpeptide (L692,429 and MK-677) and two peptide [GH-releasing peptide (GHRP)-6 and ghrelin] agonists were compared in binding and in signal transduction assays: calcium mobilization, inositol phosphate turnover, cAMP-responsive element (CRE), and serum-responsive element (SRE) controlled...... lower apparent affinity for ghrelin binding and surprisingly acted as a positive allosteric receptor modulator by increasing ghrelin's potency 4- to 10-fold. In contrast, the potency of GHRP-6 varied 600-fold (0.1-61 nm) depending on the signal transduction assay, and it acted as a negative allosteric...... modulator of ghrelin signaling. Unexpectedly, the maximal signaling efficacy for ghrelin was increased above what was observed with the hormone itself during coadministration with the nonendogenous agonists. It is concluded that agonists for the ghrelin receptor vary both in respect of their intrinsic...

  6. Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[D-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation.

    Science.gov (United States)

    Li, Yangmei; Cazares, Margret; Wu, Jinhua; Houghten, Richard A; Toll, Laurence; Dooley, Colette

    2016-02-11

    To optimize the structure of a μ-opioid receptor ligand, analogs H-Tyr-c[D-Lys-Xxx-Tyr-Gly] were synthesized and their biological activity was tested. The analog containing a Phe(3) was identified as not only exhibiting binding affinity 14-fold higher than the original hit but also producing agonist activity 3-fold more potent than morphine. NMR study suggested that a trans conformation at D-Lys(2)-Xxx(3) is crucial for these cyclic peptides to maintain high affinity, selectivity, and functional activity toward the μ-opioid receptor.

  7. Exogenous glucagon-like peptide-2 (GLP-2) augments GLP-2 receptor mRNA and maintains proglucagon mRNA levels in resected rats

    DEFF Research Database (Denmark)

    Koopmann, Matthew C; Nelson, David W; Murali, Sangita G

    2008-01-01

    ), crypt-villus height, and crypt cell proliferation (by bromodeoxyuridine staining) were determined. Plasma bioactive GLP-2 (by radioimmunoassay), proglucagon and GLP-2 receptor mRNA expression (by Northern blot and real-time reverse transcriptase quantitative polymerase chain reaction) were measured. GLP...... activity. Plasma bioactive GLP-2 concentration increased 70% upon resection, with an additional 54% increase upon GLP-2 infusion in resected rats (P ... GLP-2 receptor expression 3-fold in resected animals and was colocalized to vasoactive intestinal peptide-positive and endothelial nitric oxide synthase-expressing enteric neurons and serotonin-containing enteroendocrine cells in the jejunum and ileum of resected rats. CONCLUSIONS: Exogenous GLP-2...

  8. Role of basic amino acids of the human angiotensin type 1 receptor in the binding of the non-peptide antagonist candesartan

    Directory of Open Access Journals (Sweden)

    Georges Vauquelin

    2001-03-01

    Full Text Available To explain the insurmountable/long-lasting binding of biphenyltetrazole-containing AT1-receptor antagonists such as candesartan, to the human angiotensin II type 1-receptor, a model is proposed in which the basic amino acids Lys199 and Arg 167 of the receptor interact respectively with the carboxylate and the tetrazole group of the antagonists. To validate this model, we have investigated the impact of substitution of Lys199 by Ala or Gln and of Arg167 by Ala on the binding properties of [3H]candesartan and on competition binding by candesartan, EXP3174, irbesartan, losartan, angiotensin II (Ang II and [Sar1-Ile8]angiotensin. Our results indicate that both amino acids play an important role in the AT1-receptor ligand binding. Whereas the negative charge of Lys 199 is involved in an ionic bond with the end-standing carboxylate group of the peptide ligands, its polarity also contributes to the non-peptide antagonist binding. Substitution of Arg167 by Ala completely abolished [3H]Ang II, as well as [3H] candesartan, binding. Whereas these results are in line with the proposed model, it cannot be excluded that both amino acid residues are important for the structural integrity of the AT1-receptor with respect to its ligand binding properties.

  9. Discovery and cardioprotective effects of the first non-Peptide agonists of the G protein-coupled prokineticin receptor-1.

    Directory of Open Access Journals (Sweden)

    Adeline Gasser

    Full Text Available Prokineticins are angiogenic hormones that activate two G protein-coupled receptors: PKR1 and PKR2. PKR1 has emerged as a critical mediator of cardiovascular homeostasis and cardioprotection. Identification of non-peptide PKR1 agonists that contribute to myocardial repair and collateral vessel growth hold promises for treatment of heart diseases. Through a combination of in silico studies, medicinal chemistry, and pharmacological profiling approaches, we designed, synthesized, and characterized the first PKR1 agonists, demonstrating their cardioprotective activity against myocardial infarction (MI in mice. Based on high throughput docking protocol, 250,000 compounds were computationally screened for putative PKR1 agonistic activity, using a homology model, and 10 virtual hits were pharmacologically evaluated. One hit internalizes PKR1, increases calcium release and activates ERK and Akt kinases. Among the 30 derivatives of the hit compound, the most potent derivative, IS20, was confirmed for its selectivity and specificity through genetic gain- and loss-of-function of PKR1. Importantly, IS20 prevented cardiac lesion formation and improved cardiac function after MI in mice, promoting proliferation of cardiac progenitor cells and neovasculogenesis. The preclinical investigation of the first PKR1 agonists provides a novel approach to promote cardiac neovasculogenesis after MI.

  10. Metformin ameliorates lipotoxicity-induced mesangial cell apoptosis partly via upregulation of glucagon like peptide-1 receptor (GLP-1R).

    Science.gov (United States)

    Kim, Dong-il; Park, Min-jung; Heo, Young-ran; Park, Soo-hyun

    2015-10-15

    Glucagon like peptide-1 receptor (GLP-1R), known to be expressed in pancreatic beta cells, is also expressed in glomerular mesangial cells and its agonist has protective effects in diabetic nephropathy. However, its regulatory mechanisms by lipotoxicity in glomerular mesangial cells are not understood. We found that palmitate-mediated lipotoxicity increased apoptosis and decreased GLP-1R expression in a rat mesangial cell line. Silencing GLP-1R expression also increased mesangial cell apoptosis. Interestingly, metformin, one of the biguanide drugs that has anti-diabetic effects, attenuated lipotoxicity-induced mesangial cell apoptosis and restored GLP-1R expression. Moreover, this treatment alleviated GLP-1R knockdown-induced mesangial cell apoptosis. To further evaluate in vivo, diabetic obese db/db mice were administered metformin. Glomerular GLP-1R expression was diminished in db/db mice, as compared with db/m control mice. However, this decrease significantly recovered on metformin administration. Together, these data provide novel evidence that lipotoxicity decreases the mesangial GLP-1R expression in intact cells and in vivo. The decrease induced mesangial cell apoptosis. Furthermore, we provided the evidence that metformin treatment has a renal protective effect partly via increased mesangial GLP-1R expression. Our data suggested that regulation of GLP-1R expression could be a promising approach to treat diabetic nephropathy and the novel mechanism of metformin mediated GLP-1R regulation. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. New Potential Targets of Glucagon-Like Peptide 1 Receptor Agonists in Pancreatic β-Cells and Hepatocytes

    Directory of Open Access Journals (Sweden)

    Won-Young Lee

    2017-02-01

    Full Text Available It is well known that both insulin resistance and decreased insulin secretory capacity are important factors in the pathogenesis of type 2 diabetes mellitus (T2DM. In addition to genetic factors, obesity and lipotoxicity can increase the risk of T2DM. Glucagon-like peptide 1 (GLP-1 receptor agonists are novel antidiabetic drugs with multiple effects. They can stimulate glucose-dependent insulin secretion, inhibit postprandial glucagon release, delay gastric emptying, and induce pancreatic β-cell proliferation. They can also reduce the weight of patients with T2DM and relieve lipotoxicity at the cellular level. Many intracellular targets of GLP-1 have been found, but more remain to be identified. Elucidating these targets could be a basis for developing new potential drugs. My colleagues and I have investigated new targets of GLP-1, with a particular focus on pancreatic β-cell lines and hepatic cell lines. Herein, I summarize the recent work from my laboratory, with profound gratitude for receiving the prestigious 2016 Namgok Award.

  12. Human Anti-Oxidation Protein A1M—A Potential Kidney Protection Agent in Peptide Receptor Radionuclide Therapy

    Directory of Open Access Journals (Sweden)

    Jonas Ahlstedt

    2015-12-01

    Full Text Available Peptide receptor radionuclide therapy (PRRT has been in clinical use for 15 years to treat metastatic neuroendocrine tumors. PRRT is limited by reabsorption and retention of the administered radiolabeled somatostatin analogues in the proximal tubule. Consequently, it is essential to develop and employ methods to protect the kidneys during PRRT. Today, infusion of positively charged amino acids is the standard method of kidney protection. Other methods, such as administration of amifostine, are still under evaluation and show promising results. α1-microglobulin (A1M is a reductase and radical scavenging protein ubiquitously present in plasma and extravascular tissue. Human A1M has antioxidation properties and has been shown to prevent radiation-induced in vitro cell damage and protect non-irradiated surrounding cells. It has recently been shown in mice that exogenously infused A1M and the somatostatin analogue octreotide are co-localized in proximal tubules of the kidney after intravenous infusion. In this review we describe the current situation of kidney protection during PRRT, discuss the necessity and implications of more precise dosimetry and present A1M as a new, potential candidate for renal protection during PRRT and related targeted radionuclide therapies.

  13. The involvement of sigma1 receptors in donepezil-induced rescue of hippocampal LTP impaired by beta-amyloid peptide.

    Science.gov (United States)

    Solntseva, E I; Kapai, N A; Popova, O V; Rogozin, P D; Skrebitsky, V G

    2014-07-01

    Donepezil is a potent acetylcholinesterase inhibitor used for the treatment of Alzheimer's disease (AD). Additional therapeutically relevant target for donepezil is sigma1 receptor (Sig1-R). Beta-amyloid peptide (Aβ) is believed to contribute to the pathogenesis of AD. In our previous work (Kapai et al., 2012), we have shown that donepezil antagonizes the suppressive action of Aβ(1-42) on long-term potentiation (LTP) in rat hippocampal slices. The purpose of the present study was to determine whether Sig1-R is involved into the mechanisms of donepezil action. For this purpose, we have tested whether agonist of Sig1-R PRE-084 mimics, and antagonist of Sig1-R haloperidol abolishes the effect of donepezil. Population spikes (PSs) were recorded from the pyramidal layer of the CA1 region of rat hippocampal slices. Drugs were applied by addition to the perfusate starting 15 min before and ending 5 min after the tetanus. In the control group, the amplitude of PS 30 min post-tetanus reached 153±10%. Aβ (200 nM) markedly suppressed the LTP magnitude or even caused the suppression of baseline PS (82±8%, Pdonepezil was co-administered with Aβ (136±11%, Pdonepezil and 0.5 μM haloperidol and have found that haloperidol antagonized the stimulating effect of donepezil on LTP (92±6%, Pdonepezil-induced rescue of hippocampal LTP impaired by Aβ. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Saliva induces expression of antimicrobial peptides and promotes intracellular killing of bacteria in keratinocytes by epidermal growth factor receptor transactivation.

    Science.gov (United States)

    Mohanty, T; Alberius, P; Schmidtchen, A; Reiss, K; Schröder, J-M; Sørensen, O E

    2017-02-01

    Wounds in the oral cavity, constantly exposed to both saliva and bacteria, heal quickly without infection. Furthermore, during licking of skin wounds, saliva promotes wound healing and plays a role in keeping the wound free of infection. To investigate whether saliva induces expression of antimicrobial peptides (AMPs) in human epidermal keratinocytes and whether saliva promotes clearance of intracellular bacteria in these cells. Expression of AMPs was investigated in the oral mucosa and ex vivo injured skin by immunohistochemistry. Human beta-defensin-3 expression was investigated in epidermal keratinocytes after saliva stimulation, using real-time polymerase chain reaction and immunofluorescence. We found higher expression of AMPs in the oral mucosa than in the epidermis. Saliva accelerated the injury-induced expression of AMPs in human skin ex vivo and was a potent inducer of the expression of AMPs in epidermal keratinocytes. The expression of AMPs was induced by metalloproteinase-dependent epidermal growth factor receptor (EGFR) transactivation mediated by a salivary lipid. Saliva increased the intracellular clearance of Staphylococcus aureus in keratinocytes through EGFR activation. These findings suggest a previously unreported role of saliva in innate immunity and demonstrate for the first time that saliva induces gene expression in epidermal keratinocytes. © 2016 British Association of Dermatologists.

  15. Variations in Peptide YY and Y2 Receptor Genes Are Associated With Severe Obesity in Pima Indian Men

    Science.gov (United States)

    Ma, Lijun; Tataranni, P. Antonio; Hanson, Robert L.; Infante, Aniello M.; Kobes, Sayuko; Bogardus, Clifton; Baier, Leslie J.

    2005-01-01

    Peptide YY (PYY) and Y2 receptor (Y2R) may be important in the central regulation of body weight and food intake. To determine whether genetic variation in PYY and/or Y2R may contribute to morbid obesity in humans, these genes were sequenced in 83 extremely obese Pima Indians (BMI ≥50 kg/m2). Sequencing of PYY identified three single nucleotide polymorphsms (SNPs) in the untranslated region. Sequencing of the Y2R coding region identified one missense (Ala172Thr) substitution and two silent substitutions. Eight additional SNPs in the 5′ untranslated region of Y2R were identified from public databases. These SNPs were genotyped in 489 full-heritage adult Pimas (362 severely obese and 127 non-diabetic, nonobese subjects), who are not first-degree relatives, for association analysis. The PYY variants were not associated with obesity, whereas four variants from two haplotype blocks in Y2R were marginally associated (P = 0.054–0.067) with obesity. However, if the analysis was restricted to men (n = 167, 100 obese and 67 lean), the PYY variants and two SNPs in Y2R that were in complete linkage disequilibrium were significantly associated with severe obesity (P = 0.001 and P = 0.002, respectively). Our data suggest that the PYY-Y2R pathway may influence body weight through a sex-specific mechanism, but this finding requires confirmation in other populations. PMID:15855352

  16. Spergularia marina Induces Glucagon-Like Peptide-1 Secretion in NCI-H716 Cells Through Bile Acid Receptor Activation

    Science.gov (United States)

    Kim, Kyong; Lee, Yu Mi; Rhyu, Mee-Ra

    2014-01-01

    Abstract Spergularia marina Griseb. (SM) is a halophyte that grows in mud flats. The aerial portions of SM have been eaten as vegetables and traditionally used to prevent chronic diseases in Korea. However, there has been no scientific report that demonstrates the pharmacological effects of SM. Glucagon-like peptide-1 (GLP-1) is important for the maintenance of glucose and energy homeostasis through acting as a signal in peripheral and neural systems. To discover a functional food for regulating glucose and energy homeostasis, we evaluated the effect of an aqueous ethanolic extract (AEE) of SM on GLP-1 release from enteroendocrine NCI-H716 cells. In addition, we explored the Takeda G-protein-coupled receptor 5 (TGR5) agonist activity of AEE-SM in Chinese hamster ovary (CHO)-K1 cells transiently transfected with human TGR5. As a result, treatment of NCI-H716 cells with AEE-SM increased GLP-1 secretion and intracellular Ca2+ and cyclic AMP (cAMP) levels in a dose-dependent manner. Transfection of NCI-H716 cells with TGR5-specific small interference RNA inhibited AEE-SM-induced GLP-1 secretion and the increase in Ca2+ and cAMP levels. Moreover, AEE-SM showed that the TGR5 agonist activity in CHO-K1 cells transiently transfected with TGR5. The results suggest that AEE-SM might be a candidate for a functional food to regulate glucose and energy homeostasis. PMID:25260089

  17. Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE for Metastatic Neuroendocrine Tumor Occurring in Association with Multiple Endocrine Neoplasia Type 1 and Cushing's Syndrome

    OpenAIRE

    Naik, Chinna; Basu, Sandip

    2017-01-01

    Neuroendocrine tumor (NET) occurring in association with other endocrine syndromes forms a distinct entity. The aim was to assess the therapy response profile of the routine peptide receptor radionuclide therapy (PRRT) in this relatively uncommon but clinically challenging subgroup of patients. A retrospective analysis was undertaken from the case records from those who were treated with 177Lu-DOTATATE for metastatic NET. In addition to assessing the therapeutic efficacy, emphasis was also gi...

  18. The intestinotrophic peptide, GLP-2, counteracts the gastrointestinal atrophy in mice induced by the epidermal growth factor receptor inhibitor, erlotinib, and cisplatin

    DEFF Research Database (Denmark)

    Rasmussen, Andreas Rosén; Viby, Niels-Erik; Hare, Kristine Juul

    2010-01-01

    Erlotinib, an epidermal-growth-factor receptor inhibitor, belongs to a new generation of targeted cancer therapeutics. Gastrointestinal side-effects are common and have been markedly aggravated when erlotinib is combined with cytostatics. We examined the effects of erlotinib alone and combined wi...... with the cytostatic, cisplatin, on the gastrointestinal tract and examined whether glucagon-like peptide-2 (GLP-2), an intestinal hormone with potent intestinotrophic properties, might counteract the possible damaging effects of the treatments....

  19. Peptide YY.

    Science.gov (United States)

    Chandarana, Keval; Batterham, Rachel

    2008-02-01

    This review discusses recent studies examining the effects of peptide YY on energy homeostasis, highlights the emerging hedonic effects of peptide YY and evaluates the therapeutic potential of the peptide YY system. A role for exogenous PYY3-36 as an anorectic agent in obese humans and rodents has been established and weight loss effects demonstrated in obese rodents. New lines of evidence support a role for endogenous peptide YY in regulating energy homeostasis. The NPY-Y2 receptor mediates the anorectic actions of PYY3-36 with rodent studies implicating the hypothalamus, vagus and brainstem as key target sites. Functional imaging in humans has confirmed that PYY3-36 activates brainstem and hypothalamic regions. The greatest effects, however, were observed within the orbitofrontal cortex, a brain region involved in reward processing. Further evidence for a hedonic role for PYY3-36 is supported by rodent studies showing that PYY3-36 decreases the motivation to seek high-fat food. Rodent studies using selective Y2 agonists and strategies combining PYY3-36/Y2 agonists with other anorectic agents have revealed increased anorectic and weight-reducing effects. Peptide YY plays a role in the integrative regulation of metabolism. The emerging hedonic effects of peptide YY together with the weight-reducing effects observed in obese rodents suggest that targeting the peptide YY system may offer a therapeutic strategy for obesity.

  20. Lupin Peptides Modulate the Protein-Protein Interaction of PCSK9 with the Low Density Lipoprotein Receptor in HepG2 Cells

    Science.gov (United States)

    Lammi, Carmen; Zanoni, Chiara; Aiello, Gilda; Arnoldi, Anna; Grazioso, Giovanni

    2016-07-01

    Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recently identified as a new useful target for hypercholesterolemia treatment. This work demonstrates that natural peptides, deriving from the hydrolysis of lupin protein and absorbable at intestinal level, are able to inhibit the protein-protein interaction between PCSK9 and the low density lipoprotein receptor (LDLR). In order to sort out the best potential inhibitors among these peptides, a refined in silico model of the PCSK9/LDLR interaction was developed. Docking, molecular dynamics (MD) simulations and peptide binding energy estimations, by MM-GBSA approach, permitted to select the two best candidates among tested peptides that were synthesized and evaluated for their inhibitory activity. The most active was P5 that induced a concentration dependent inhibition of the PCSK9-LDLR binding, with an IC50 value equal to 1.6 ± 0.33 μM. Tested at a 10 μM concentration, this peptide increased by 66 ± 21.4% the ability of HepG2 cells to take up LDL from the extracellular environment.

  1. Solid-phase peptide synthesis of endothelin receptor antagonists on novel flexible, styrene-acryloyloxyhydroxypropyl methacrylate-tripropyleneglycol diacrylate [SAT] resin.

    Science.gov (United States)

    Siyad, M A; Nair, Arun S V; Kumar, G S Vinod

    2010-03-08

    Novel cross-linked polymeric support by the copolymerization of styrene and 3-(acryloyloxy)-2-hydroxypropyl methacrylate with Tri(propyleneglycol) diacryalte (SAT) for solid-phase peptide synthesis is presented here. The synthesis of SAT is based on the cross-linking of 3-(acryloyloxy)-2-hydroxypropyl methacrylate with styrene by free-radical suspension polymerization, consisting of an ester and a secondary hydroxyl group. An additional cross-linker tri(propyleneglycol) diacryalte provides a hydrophilic environment throughout the resin, which will enhance the physicochemical properties of the resin toward organic synthesis. The resins were synthesized in various cross-linking densities to check the swelling property, mechanical stability, and functional loading capacity. The resin was characterized by the IR, (13)C NMR, and SEM techniques. The extent of swelling properties of the polymer of different cross-linking densities were studied and compared with Merrifield resin and TentaGel. To demonstrate the efficiency of SAT support was proved by synthesizing the challenging peptide sequence of acyl carrier protein (ACP) and compared with commercially available Merrifield resin. It was further tested by synthesizing endothelial receptor antagonist peptides using SAT resin and compared with commercially available TentaGel resin. The standard Fmoc strategy was adopted for peptide synthesis and was characterized by MALDI-TOF MS and analyzed the purity of peptides by HPLC.

  2. Canonical and Cross-reactive Binding of NK Cell Inhibitory Receptors to HLA-C Allotypes Is Dictated by Peptides Bound to HLA-C.

    Science.gov (United States)

    Sim, Malcolm J W; Malaker, Stacy A; Khan, Ayesha; Stowell, Janet M; Shabanowitz, Jeffrey; Peterson, Mary E; Rajagopalan, Sumati; Hunt, Donald F; Altmann, Daniel M; Long, Eric O; Boyton, Rosemary J

    2017-01-01

    Human natural killer (NK) cell activity is regulated by a family of killer cell immunoglobulin-like receptors (KIRs) that bind human leukocyte antigen (HLA) class I. Combinations of KIR and HLA genotypes are associated with disease, including susceptibility to viral infection and disorders of pregnancy. KIR2DL1 binds HLA-C alleles of group C2 (Lys80). KIR2DL2 and KIR2DL3 bind HLA-C alleles of group C1 (Asn80). However, this model cannot explain HLA-C allelic effects in disease or the impact of HLA-bound peptides. The goal of this study was to determine the extent to which the endogenous HLA-C peptide repertoire can influence the specific binding of inhibitory KIR to HLA-C allotypes. The impact of HLA-C bound peptide on inhibitory KIR binding was investigated taking advantage of the fact that HLA-C*05:01 (HLA-C group 2, C2) and HLA-C*08:02 (HLA-C group 1, C1) have identical sequences apart from the key KIR specificity determining epitope at residues 77 and 80. Endogenous peptides were eluted from HLA-C*05:01 and used to test the peptide dependence of KIR2DL1 and KIR2DL2/3 binding to HLA-C*05:01 and HLA-C*08:02 and subsequent impact on NK cell function. Specific binding of KIR2DL1 to the C2 allotype occurred with the majority of peptides tested. In contrast, KIR2DL2/3 binding to the C1 allotype occurred with only a subset of peptides. Cross-reactive binding of KIR2DL2/3 with the C2 allotype was restricted to even fewer peptides. Unexpectedly, two peptides promoted binding of the C2 allotype-specific KIR2DL1 to the C1 allotype. We showed that presentation of endogenous peptides or HIV Gag peptides by HLA-C can promote KIR cross-reactive binding. KIR2DL2/3 binding to C1 is more peptide selective than that of KIR2DL1 binding to C2, providing an explanation for KIR2DL3-C1 interactions appearing weaker than KIR2DL1-C2. In addition, cross-reactive binding of KIR is characterized by even higher peptide selectivity. We demonstrate a hierarchy of functional peptide

  3. Biopolymeric receptor for peptide recognition by molecular imprinting approach—Synthesis, characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Lav Kumar; Singh, Monika; Singh, Meenakshi, E-mail: meenakshi_s4@rediffmail.com

    2014-12-01

    The present work is focused on the development of a biocompatible zwitterionic hydrogel for various applications in analytical chemistry. Biopolymer chitosan was derivatized to obtain a series of zwitterionic hydrogel samples. Free amino groups hanging on the biopolymeric chain were reacted with γ-butyrolactone to quaternize the N-centers of polymeric chain. N,N-methylene-bis-acrylamide acts as a crosslinker via Michael-type addition in the subsequent step and facilitated gelation of betainized chitosan. These biopolymeric hydrogel samples were fully characterized by FTIR, {sup 1}H NMR, {sup 13}C NMR spectra, SEM and XRD. Hydrogels were further characterized for their swelling behavior at varying parameters. The extent of swelling was perceived to be dictated by solvent composition such as pH, ionic strength and temperature. This valuable polymeric format is herein chosen to design an artificial receptor for dipeptide ‘carnosine’, which has adequate societal significance to be analytically determined, by molecular imprinting. Electrostatic interactions along with complementary H-bonding and other hydrophobic interactions inducing additional synergetic effect between the template (carnosine) and the imprinted polymer led to the formation of imprinted sites. The MIP was able to selectively and specifically take up carnosine from aqueous solution quantitatively. Thus prepared MIPs were characterized by FTIR spectroscopy, SEM providing evidence for the quality and quantity of imprinted gels. The binding studies showed that the MIP illustrated good recognition for carnosine as compared to non-imprinted polymers (NIPs). Detection limit was estimated as 3.3 μg mL{sup −1}. Meanwhile, selectivity experiments demonstrated that imprinted gel had a high affinity to carnosine in the presence of close structural analogues (interferrants). - Highlights: • Development of a biocompatible zwitterionic hydrogel • A series of chitosan-derived zwitterionic hydrogel samples

  4. Induction of Apoptosis and T Helper 2 (Th2) Responses Correlates with Peptide Affinity for the Major Histocompatibility Complex in Self-reactive T Cell Receptor Transgenic Mice

    Science.gov (United States)

    Pearson, C.I.; van Ewijk, W.; McDevitt, H.O.

    1997-01-01

    Multiple sclerosis is an autoimmune disease thought to be mediated by CD4+ T helper cells (Th). Experimental autoimmune encephalomyelitis is a rodent model of multiple sclerosis and has been used extensively to explore a variety of immunotherapies using soluble protein or peptide antigens. The underlying mechanisms of such therapy have been attributed to induction of T cell anergy, a switch in Th1 to Th2 responses, or peripheral deletion of autoreactive T cells. In this study, we have developed transgenic mice expressing a T cell receptor (TCR) specific for the NH2-terminal peptide Ac1-11 of the autoantigen myelin basic protein to explore the mechanism of soluble peptide therapy. T cells from these mice are highly skewed toward the CD4 population and have an abnormal thymic architecture, a phenomenon found in other TCR transgenic mice that exhibit a highly skewed CD4/CD8 ratio. Soluble Ac1-11 or the analogues Ac1-11[4A] or Ac1-11[4Y] (which bind to the major histocompatibility complex [MHC] class II molecule I-Au with increasing affinities) given intravenously activates T cells, rendering cells hyperresponsive in vitro for at least two days after injection. Concomitantly, T cells apoptose in the periphery, the degree of which correlates with the affinity of the peptide for the MHC. In addition, a shift in the T helper phenotype of the surviving T cells occurs such that the low affinity peptide, Ac1-11, induces primarily a Th1 response, whereas the highest affinity peptide, Ac1-11[4Y], induces primarily a Th2 type response. These data show that both the nature and the presumed number of the peptide–MHC complexes formed during specific peptide therapy affect both the degree of peripheral programmed cell death as well as the outcome of the T helper subset response in vivo, leading to amelioration of disease. PMID:9034138

  5. Investigation of CGRP receptors and peptide pharmacology in human coronary arteries. Characterization with a nonpeptide antagonist

    DEFF Research Database (Denmark)

    Hasbak, Philip; Saetrum Opgaard, Ole; Eskesen, Karen

    2003-01-01

    .8, and 6.3 M, respectively. Preincubation with alphaCGRP(8-37) (10(-7) -10(-5) M) and a novel nonpeptide CGRP antagonist "Compound 1" (WO98/11128) (10(-7)-10(-5) M) caused a dose-dependent rightward shift of the concentration-response curves for alphaCGRP with pA(2) values of 7.0 and 7.1, respectively....... Preincubation with alphaCGRP(8-37) (10(-6) M) and Compound 1 (10(-6) M) caused significant rightward shift of the concentration-response curves for AM and amylin as well with pK B values between 6.6 and 7.5. Preincubation with AM(22-52) had no antagonistic effect on the AM and amylin response, neither did....... Compound 1 acted as a nonpeptide antagonist at the CGRP1 receptor and could thus become a tool for the study of CGRP-mediated functional responses in human tissue....

  6. Radiolabelled peptides for oncological diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

    2012-02-15

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

  7. On-resin N-formylation of peptides: a head-to-head comparison of reagents in solid-phase synthesis of ligands for formyl peptide receptors

    DEFF Research Database (Denmark)

    Christensen, Simon Bendt; Hansen, Anna Mette; Franzyk, Henrik

    2017-01-01

    General conditions for efficient on-resin N-formylation of peptides were identified by screening of a number of reagents comprising aliphatic formates (ethyl formate, 2,2,2-trifluoroethyl formate, and cyanomethyl formate), aromatic esters (phenyl formate and p-nitrophenyl formate), and N-formylim......General conditions for efficient on-resin N-formylation of peptides were identified by screening of a number of reagents comprising aliphatic formates (ethyl formate, 2,2,2-trifluoroethyl formate, and cyanomethyl formate), aromatic esters (phenyl formate and p-nitrophenyl formate), and N......-formylimidazole and in situ activation of formic acid with the coupling reagent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. Initially, reaction time and influence of solvent were examined for the formylation of a short model peptide. The most efficient reagents were examined further by using different linkers and solid...

  8. A cleavable signal peptide enhances cell surface delivery and heterodimerization of Cerulean-tagged angiotensin II AT1 and bradykinin B2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Quitterer, Ursula, E-mail: ursula.quitterer@pharma.ethz.ch [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland); Pohl, Armin; Langer, Andreas; Koller, Samuel; AbdAlla, Said [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland)

    2011-06-10

    Highlights: {yields} A new FRET-based method detects AT1/B2 receptor heterodimerization. {yields} First time application of AT1-Cerulean as a FRET donor. {yields} Method relies on signal peptide-enhanced cell surface delivery of AT1-Cerulean. {yields} A high FRET efficiency revealed efficient heterodimerization of AT1/B2R proteins. {yields} AT1/B2R heterodimers were functionally coupled to desensitization mechanisms. -- Abstract: Heterodimerization of the angiotensin II AT1 receptor with the receptor for the vasodepressor bradykinin, B2R, is known to sensitize the AT1-stimulated response of hypertensive individuals in vivo. To analyze features of that prototypic receptor heterodimer in vitro, we established a new method that uses fluorescence resonance energy transfer (FRET) and applies for the first time AT1-Cerulean as a FRET donor. The Cerulean variant of the green fluorescent protein as donor fluorophore was fused to the C-terminus of AT1, and the enhanced yellow fluorescent protein (EYFP) as acceptor fluorophore was fused to B2R. In contrast to AT1-EGFP, the AT1-Cerulean fusion protein was retained intracellularly. To facilitate cell surface delivery of AT1-Cerulean, a cleavable signal sequence was fused to the receptor's amino terminus. The plasma membrane-localized AT1-Cerulean resembled the native AT1 receptor regarding ligand binding and receptor activation. A high FRET efficiency of 24.7% between membrane-localized AT1-Cerulean and B2R-EYFP was observed with intact, non-stimulated cells. Confocal FRET microscopy further revealed that the AT1/B2 receptor heterodimer was functionally coupled to receptor desensitization mechanisms because activation of the AT1-Cerulean/B2R-EYFP heterodimer with a single agonist triggered the co-internalization of AT1/B2R. Receptor co-internalization was sensitive to inhibition of G protein-coupled receptor kinases, GRKs, as evidenced by a GRK-specific peptide inhibitor. In agreement with efficient AT1/B2R

  9. Calcineurin regulates homologous desensitization of natriuretic peptide receptor-A and inhibits ANP-induced testosterone production in MA-10 cells.

    Science.gov (United States)

    Henesy, Michelle B; Britain, Andrea L; Zhu, Bing; Amable, Lauren; Honkanen, Richard E; Corbin, Jackie D; Francis, Sharron H; Rich, Thomas C

    2012-01-01

    Receptor desensitization is a ubiquitous regulatory mechanism that defines the activatable pool of receptors, and thus, the ability of cells to respond to environmental stimuli. In recent years, the molecular mechanisms controlling the desensitization of a variety of receptors have been established. However, little is known about the molecular mechanisms that underlie desensitization of natriuretic peptide receptors, including natriuretic peptide receptor-A (NPR-A). Here we report that calcineurin (protein phosphatase 2B, PP2B, PPP3C) regulates homologous desensitization of NPR-A in murine Leydig tumor (MA-10) cells. We demonstrate that both pharmacological inhibition of calcineurin activity and siRNA-mediated suppression of calcineurin expression potentiate atrial natriuretic peptide (ANP)-induced cGMP synthesis. Treatment of MA-10 cells with inhibitors of other phosphoprotein phosphatases had little or no effect on ANP-induced cGMP accumulation. In addition, overexpression of calcineurin blunts ANP-induced cGMP synthesis. We also present data indicating that the inhibition of calcineurin potentiates ANP-induced testosterone production. To better understand the contribution of calcineurin in the regulation of NPR-A activity, we examined the kinetics of ANP-induced cGMP signals. We observed transient ANP-induced cGMP signals, even in the presence of phosphodiesterase inhibitors. Inhibition of both calcineurin and phosphodiesterase dramatically slowed the decay in the response. These observations are consistent with a model in which calcineurin mediated dephosphorylation and desensitization of NPR-A is associated with significant inhibition of cGMP synthesis. PDE activity hydrolyzes cGMP, thus lowering intracellular cGMP toward the basal level. Taken together, these data suggest that calcineurin plays a previously unrecognized role in the desensitization of NPR-A and, thereby, inhibits ANP-mediated increases in testosterone production.

  10. Monitoring β-arrestin recruitment via β-lactamase enzyme fragment complementation: purification of peptide E as a low-affinity ligand for mammalian bombesin receptors.

    Directory of Open Access Journals (Sweden)

    Yuichi Ikeda

    Full Text Available Identification of cognate ligands for G protein-coupled receptors (GPCRs provides a starting point for understanding novel regulatory mechanisms. Although GPCR ligands have typically been evaluated through the activation of heterotrimeric G proteins, recent studies have shown that GPCRs signal not only through G proteins but also through β-arrestins. As such, monitoring β-arrestin signaling instead of G protein signaling will increase the likelihood of identifying currently unknown ligands, including β-arrestin-biased agonists. Here, we developed a cell-based assay for monitoring ligand-dependent GPCR-β-arrestin interaction via β-lactamase enzyme fragment complementation. Inter alia, β-lactamase is a superior reporter enzyme because of its cell-permeable fluorescent substrate. This substrate makes the assay non-destructive and compatible with fluorescence-activated cell sorting (FACS. In a reporter cell, complementary fragments of β-lactamase (α and ω were fused to β-arrestin 2 and GPCR, respectively. Ligand stimulation initiated the interaction of these chimeric proteins (β-arrestin-α and GPCR-ω, and this inducible interaction was measured through reconstituted β-lactamase activity. Utilizing this system, we screened various mammalian tissue extracts for agonistic activities on human bombesin receptor subtype 3 (hBRS3. We purified peptide E as a low-affinity ligand for hBRS3, which was also found to be an agonist for the other two mammalian bombesin receptors such as gastrin-releasing peptide receptor (GRPR and neuromedin B receptor (NMBR. Successful purification of peptide E has validated the robustness of this assay. We conclude that our newly developed system will facilitate the discovery of GPCR ligands.

  11. Histone Deacetylase Inhibitors Modulate the Transcriptional Regulation of Guanylyl Cyclase/Natriuretic Peptide Receptor-A Gene

    Science.gov (United States)

    Kumar, Prerna; Tripathi, Satyabha; Pandey, Kailash N.

    2014-01-01

    Atrial natriuretic peptide (ANP) binds guanylyl cyclase-A/natriuretic peptide receptor-A (GC-A/NPRA) and produces the intracellular second messenger, cGMP, which regulates cardiovascular homeostasis. We sought to determine the function of histone deacetylases (HDACs) in regulating Npr1 (coding for GC-A/NPRA) gene transcription, using primary mouse mesangial cells treated with class-specific HDAC inhibitors (HDACi). Trichostatin A, a pan inhibitor, and mocetinostat (MGCD0103), a class I HDAC inhibitor, significantly enhanced Npr1 promoter activity (by 8- and 10-fold, respectively), mRNA levels (4- and 5.3-fold, respectively), and NPRA protein (2.7- and 3.5-fold, respectively). However, MC1568 (class II HDAC inhibitor) had no discernible effect. Overexpression of HDAC1 and HDAC2 significantly attenuated Npr1 promoter activity, whereas HDAC3 and HDAC8 had no effect. HDACi-treated cultured cells in vitro and intact animals in vivo showed significantly reduced binding of HDAC1 and -2 and increased accumulation of acetylated H3-K9/14 and H4-K12 at the Npr1 promoter. Deletional analyses of the Npr1 promoter along with ectopic overexpression and inhibition of Sp1 confirmed that HDACi-induced Npr1 gene transcription is accomplished by Sp1 activation. Furthermore, HDACi attenuated the interaction of Sp1 with HDAC1/2 and promoted Sp1 association with p300 and p300/cAMP-binding protein-associated factor; it also promoted the recruitment of p300 and p300/cAMP-binding protein-associated factor to the Npr1 promoter. Our results demonstrate that trichostatin A and MGCD0103 enhanced Npr1 gene expression through inhibition of HDAC1/2 and increased both acetylation of histones (H3-K9/14, H4-K12) and Sp1 by p300, and their recruitment to Npr1 promoter. Our findings define a novel epigenetic regulatory mechanism that governs Npr1 gene transcription. PMID:24451378

  12. Genetic susceptibility to refractive error: association of vasoactive intestinal peptide receptor 2 (VIPR2 with high myopia in Chinese.

    Directory of Open Access Journals (Sweden)

    Wai Chi Yiu

    Full Text Available Myopia is the most common ocular disease worldwide. We investigated the association of high myopia with the common single nucleotide polymorphisms (SNPs of five candidate genes - early growth response 1 (EGR1, v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS, jun oncogene (JUN, vasoactive intestinal peptide (VIP, and vasoactive intestinal peptide receptor 2 (VIPR2. We recruited 1200 unrelated Chinese subjects with 600 cases (spherical equivalent ≤-8.00 diopters and 600 controls (spherical equivalent within ±1.00 diopter. A discovery sample set was formed from 300 cases and 300 controls, and a replication sample set from the remaining samples. Tag SNPs were genotyped for the discovery sample set, and the most significant haplotypes and their constituent SNPs were followed up with the replication sample set. The allele and haplotype frequencies in cases and controls were compared by logistic regression adjusted for sex and age to give P a values, and multiple comparisons were corrected by permutation test to give P aemp values. Odd ratios (OR were calculated accordingly. In the discovery phase, EGR1, JUN and VIP did not show any significant association while FOS and VIPR2 demonstrated significant haplotype association with high myopia. In the replication phase, the haplotype association for VIPR2 was successfully replicated, but not FOS. In analysis combining both sample sets, the most significant association signals of VIPR2 were the single marker rs2071625 (P a = 0.0008, P aemp = 0.0046 and OR = 0.75 and the 4-SNP haplotype window rs2071623-rs2071625-rs2730220-rs885863 (omnibus test, P a = 9.10e-10 and P aemp = 0.0001 with one protective haplotype (GGGG: P aemp = 0.0002 and OR = 0.52 and one high-risk haplotype (GAGA: P aemp = 0.0027 and OR = 4.68. This 4-SNP haplotype window was the most significant in all sample sets examined. This is the first study to suggest a role of VIPR2 in the genetic

  13. Immunization of rabbits with synthetic peptides derived from a highly conserved β-sheet epitope region underneath the receptor binding site of influenza A virus

    Directory of Open Access Journals (Sweden)

    Ideno S

    2013-11-01

    Full Text Available Shoji Ideno,1,3 Kaoru Sakai,1 Mikihiro Yunoki,2–4 Ritsuko Kubota-Koketsu,3,5 Yuji Inoue,3 Shota Nakamura,6 Teruo Yasunaga,6 Yoshinobu Okuno,5 Kazuyoshi Ikuta3 1Infectious Pathogen Research Section, Central Research Laboratory, Research and Development Division, Japan Blood Products Organization, Kobe, Japan; 2Research and Development Promotion Section, Research and Development Division, Japan Blood Products Organization, Tokyo, Japan; 3Department of Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; 4Department of Veterinary Microbiology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan; 5Kanonji Institute, The Research Foundation for Microbial Diseases of Osaka University, Kanonji, Kagawa, Japan; 6Department of Genome Informatics, Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan Background: There is increasing concern about the speed with which health care providers can administer prophylaxis and treatment in an influenza pandemic. Generally, it takes several months to manufacture an influenza vaccine by propagation of the virus in chicken eggs or cultured cells. Newer, faster protocols for the production of vaccines that induce broad-spectrum immunity are therefore highly desirable. We previously developed human monoclonal antibody B-1 that shows broadly neutralizing activity against influenza A virus H3N2. B-1 recognizes an epitope region that includes an antiparallel β-sheet structure underneath the receptor binding site of influenza hemagglutinin (HA. In this study, the efficacy of a synthetic peptide vaccine derived from this epitope region against influenza A was evaluated. Materials and methods: Two peptides were synthesized, the upper and lower peptides. These peptides comprise amino acid residues 167–187 and 225–241, respectively, of the B-1 epitope region of HA, which is involved in

  14. Reactivation of Gαi-coupled formyl peptide receptors is inhibited by Gαq-selective inhibitors when induced by signals generated by the platelet-activating factor receptor.

    Science.gov (United States)

    Holdfeldt, André; Dahlstrand Rudin, Agnes; Gabl, Michael; Rajabkhani, Zahra; König, Gabriele M; Kostenis, Evi; Dahlgren, Claes; Forsman, Huamei

    2017-09-01

    Formyl peptide receptor (FPR)-desensitized neutrophils display increased production/release of superoxide (O2-) when activated by platelet-activating factor (PAF), a priming of the response achieved through a unique receptor crosstalk mechanism. The aim of this study was to determine the effect of an inhibitor selective for small, heterotrimeric G proteins belonging to the Gαq subclass on that receptor crosstalk. We show that signals generated by FPRs and the PAF receptor (PAFR) induce activation of the neutrophil O2-, producing NADPH-oxidase, and that response was sensitive to Gαq inhibition in cells activated by PAF, but no inhibition was obtained in cells activated by FPR agonists. Signaling in naive neutrophils is terminated fairly rapidly, and the receptors become homologously desensitized. The downstream sensitivity to Gαq inhibition in desensitized cells displaying increased production/release of O2- through the PAFR receptor crosstalk mechanism also comprised the reactivation of the FPRs, and the activation signals were redirected from the PAFR to the desensitized/reactivated FPRs. The Gαq-dependent activation signals generated by the PAFRs activate the Gαi-coupled FPRs, a receptor crosstalk that represents a novel pathway by which G protein-coupled receptors can be regulated and signaling can be turned on and off. © Society for Leukocyte Biology.

  15. In Vitro comparison of 213Bi- and 177Lu-radiation for peptide receptor radionuclide therapy.

    Science.gov (United States)

    Chan, Ho Sze; de Blois, Erik; Morgenstern, Alfred; Bruchertseifer, Frank; de Jong, Marion; Breeman, Wouter; Konijnenberg, Mark

    2017-01-01

    Absorbed doses for α-emitters are different from those for β-emitters, as the high linear energy transfer (LET) nature of α-particles results in a very dense energy deposition over a relatively short path length near the point of emission. This highly localized and therefore high energy deposition can lead to enhanced cell-killing effects at absorbed doses that are non-lethal in low-LET type of exposure. Affinities of DOTA-DPhe1-Tyr3-octreotate (DOTATATE), 115In-DOTATATE, 175Lu-DOTATATE and 209Bi-DOTATATE were determined in the K562-SST2 cell line. Two other cell lines were used for radiation response assessment; BON and CA20948, with a low and high expression of somatostatin receptors, respectively. Cellular uptake kinetics of 111In-DOTATATE were determined in CA20948 cells. CA20948 and BON were irradiated with 137Cs, 177Lu-DTPA, 177Lu-DOTATATE, 213Bi-DTPA and 213Bi-DOTATATE. Absorbed doses were calculated using the MIRDcell dosimetry method for the specific binding and a Monte Carlo model of a cylindrical 6-well plate geometry for the exposure by the radioactive incubation medium. Absorbed doses were compared to conventional irradiation of cells with 137Cs and the relative biological effect (RBE) at 10% survival was calculated. IC50 of (labelled) DOTATATE was in the nM range. Absorbed doses up to 7 Gy were obtained by 5.2 MBq 213Bi-DOTATATE, in majority the dose was caused by α-particle radiation. Cellular internalization determined with 111In-DOTATATE showed a linear relation with incubation time. Cell survival after exposure of 213Bi-DTPA and 213Bi-DOTATATE to BON or CA20948 cells showed a linear-exponential relation with the absorbed dose, confirming the high LET character of 213Bi. The survival of CA20948 after exposure to 177Lu-DOTATATE and the reference 137Cs irradiation showed the typical curvature of the linear-quadratic model. 10% Cell survival of CA20948 was reached at 3 Gy with 213Bi-DOTATATE, a factor 6 lower than the 18 Gy found for 177Lu

  16. Peptide receptor radionuclide therapy (PRRT): clinical significance of re-treatment?

    Energy Technology Data Exchange (ETDEWEB)

    Virgolini, Irene [Medical University Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Collaboration: The Innsbruck Team

    2015-12-15

    PRRT appears to be the most effective therapeutic option in the management of inoperable or metastasized NET patients with limited side effects if dose limits are respected. In patients with relapse after a first treatment period with {sup 90}Y-DOTATOC, multiple re-treatment cycles with {sup 177}Lu-DOTATATE are feasible, safe and efficacious. Quantitative imaging by dosimetry adds to formulate personalized and evidence-based treatment protocols. However, despite the large body of evidence regarding efficacy and safety of PRRT, the absence of prospective randomized controlled trials questions the utility of PRRT in the community. Furthermore, the growing number of pharmacological or liver-directed therapeutic options competes with the confusion based on the variety of somatostatin analogues to determine the optimal choice and sequencing of PRRT in the individual patient. However, the efficacy of PRRT should not be questioned rather than it should be explored as to when PRRT might be optimally applied in the sequence of available therapy modalities. The results of the present study by the Italian group [5] emphasizes that radiopharmaceuticals are still underused. Despite the huge potential of PRRT the non-availability of PRRT in many countries still limits its widespread use. After acquiring the exclusive rights for {sup 177}Lu-DOTATATE with granted orphan designation, the company Advanced Accelerator Applications (AAA) is currently running a phase III study comparing treatment with {sup 177}Lu-DOTATATE to Octreotide LAR in patients with inoperable, progressive, somatostatin receptor-positive, midgut carcinoid tumours with the aim of registering the radiopharmaceutical under the commercial name of Lutathera. Together with orphan designation also to other somatostatin-based radiopharmaceuticals, such as {sup 90}Y-DOTATOC, {sup 177}Lu-DOTATOC and the {sup 68}Ga-labelled somatostatin antagonist OPS202, these developments promote the advancement of PRRT and PET imaging

  17. Inhibition of dehydration-induced water intake by glucocorticoids is associated with activation of hypothalamic natriuretic peptide receptor-A in rat.

    Directory of Open Access Journals (Sweden)

    Chao Liu

    Full Text Available Atrial natriuretic peptide (ANP provides a potent defense mechanism against volume overload in mammals. Its primary receptor, natriuretic peptide receptor-A (NPR-A, is localized mostly in the kidney, but also is found in hypothalamic areas involved in body fluid volume regulation. Acute glucocorticoid administration produces potent diuresis and natriuresis, possibly by acting in the renal natriuretic peptide system. However, chronic glucocorticoid administration attenuates renal water and sodium excretion. The precise mechanism underlying this paradoxical phenomenon is unclear. We assume that chronic glucocorticoid administration may activate natriuretic peptide system in hypothalamus, and cause volume depletion by inhibiting dehydration-induced water intake. Volume depletion, in turn, compromises renal water excretion. To test this postulation, we determined the effect of dexamethasone on dehydration-induced water intake and assessed the expression of NPR-A in the hypothalamus. The rats were deprived of water for 24 hours to have dehydrated status. Prior to free access to water, the water-deprived rats were pretreated with dexamethasone or vehicle. Urinary volume and water intake were monitored. We found that dexamethasone pretreatment not only produced potent diuresis, but dramatically inhibited the dehydration-induced water intake. Western blotting analysis showed the expression of NPR-A in the hypothalamus was dramatically upregulated by dexamethasone. Consequently, cyclic guanosine monophosphate (the second messenger for the ANP content in the hypothalamus was remarkably increased. The inhibitory effect of dexamethasone on water intake presented in a time- and dose-dependent manner, which emerged at least after 18-hour dexamethasone pretreatment. This effect was glucocorticoid receptor (GR mediated and was abolished by GR antagonist RU486. These results indicated a possible physiologic role for glucocorticoids in the hypothalamic control of

  18. Impairment of the natriuretic peptide system in follitropin receptor knockout mice and reversal by estradiol: implications for obesity-associated hypertension in menopause.

    Science.gov (United States)

    Belo, Najara O; Sairam, M Ram; Dos Reis, Adelina M

    2008-03-01

    Estrogen is considered a major regulator of adipose tissue in females. Estrogen increases circulating levels of atrial natriuretic peptide (ANP), a hormone with renal and cardiovascular effects. The aim of this study was to determine the status of the natriuretic peptide system in female follitropin-receptor knockout (FORKO) mice that could be associated with obesity and hypertension observed in these mutants. Furthermore, estradiol treatment was used to reverse alterations observed. FORKO and wild-type (WT) mice received daily injections of estradiol for 4 d. On the fifth day, blood was collected for determination of plasma ANP levels, and selected tissues were collected for determination of ANP, natriuretic peptide receptor type-A (NPR-A) and type-C (NPR-C) gene expression by RT-PCR and binding of [(125)I]ANP by autoradiography. At 5 months of age, FORKO mice were heavier and had more adipose tissue than WT mice. FORKO mice had lower plasma ANP levels and atrial ANP gene expression and higher renal and adipocyte NPR-C gene expression than WT mice. Estradiol treatment reduced weight gain and increased atrial ANP synthesis as well as decreased ANP clearance NPR-C receptors, resulting in elevation of circulating ANP level. In conclusion, this study shows that FORKO females have an impaired natriuretic peptide system, which may contribute to the susceptibility of FORKO mice to developing age-related hypertension previously shown in these animals. This study establishes a relation between estrogen, adipose tissue, and ANP, which may have important implications in menopausal women.

  19. PLGA nanoparticles for peptide receptor radionuclide therapy of neuroendocrine tumors: a novel approach towards reduction of renal radiation dose.

    Directory of Open Access Journals (Sweden)

    Geetanjali Arora

    Full Text Available BACKGROUND: Peptide receptor radionuclide therapy (PRRT, employed for treatment of neuroendocrine tumors (NETs is based on over-expression of Somatostatin Receptors (SSTRs on NETs. It is, however, limited by high uptake and retention of radiolabeled peptide in kidneys resulting in unnecessary radiation exposure thus causing nephrotoxicity. Employing a nanocarrier to deliver PRRT drugs specifically to the tumor can reduce the associated nephrotoxicity. Based on this, (177Lu-DOTATATE loaded PLGA nanoparticles (NPs were formulated in the present study, as a potential therapeutic model for NETs. METHODOLOGY AND FINDINGS: DOTATATE was labeled with Lutetium-177 ((177Lu (labeling efficiency 98%; R(f∼0.8. Polyethylene Glycol (PEG coated (177Lu-DOTATATE-PLGA NPs (50:50 and 75:25 formulated, were spherical with mean size of 304.5±80.8 and 733.4±101.3 nm (uncoated and 303.8±67.2 and 494.3±71.8 nm (coated for PLGA(50:50 and PLGA(75:25 respectively. Encapsulation efficiency (EE and In-vitro release kinetics for uncoated and coated NPs of PLGA (50:50 & 75:25 were assessed and compared. Mean EE was 77.375±4.98% & 67.885±5.12% (uncoated and 65.385±5.67% & 58.495±5.35% (coated. NPs showed initial burst release between 16.64-21.65% with total 42.83-44.79% over 21 days. The release increased with coating to 20.4-23.95% initially and 60.97-69.12% over 21 days. In-vivo studies were done in rats injected with (177Lu-DOTATATE and (177Lu-DOTATATE-NP (uncoated and PEG-coated by imaging and organ counting after sacrificing rats at different time points over 24 hr post-injection. With (177Lu-DOTATATE, renal uptake of 37.89±10.2%ID/g was observed, which reduced to 4.6±1.97% and 5.27±1.66%ID/g with uncoated and coated (177Lu-DOTATATE-NP. The high liver uptake with uncoated (177Lu-DOTATATE-NP (13.68±3.08% ID/g, reduced to 7.20±2.04%ID/g (p = 0.02 with PEG coating. CONCLUSION: PLGA NPs were easily formulated and modified for desired release properties. PLGA

  20. Peptide receptor radionuclide therapy with {sup 177}Lu-DOTATATE: the IEO phase I-II study

    Energy Technology Data Exchange (ETDEWEB)

    Bodei, Lisa; Grana, Chiara M.; Baio, Silvia M.; Lombardo, Dario; Chinol, Marco; Paganelli, Giovanni [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); Cremonesi, Marta; Ferrari, Mahila E. [European Institute of Oncology, Division of Medical Physics, Milan (Italy); Fazio, Nicola [European Institute of Oncology, Division of Medical Oncology, Milan (Italy); Iodice, Simona [European Institute of Oncology, Division of Epidemiology and Biostatistics, Milan (Italy); Bartolomei, Mirco [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); M. Bufalini Hospital, Division of Nuclear Medicine, Cesena, FC (Italy); Sansovini, Maddalena [Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Unit of Radiometabolic Medicine, Meldola, FC (Italy)

    2011-12-15

    Peptide receptor radionuclide therapy (PRRT) is used in tumours expressing type 2 somatostatin receptors (sst{sub 2}), mainly neuroendocrine. The aim of this prospective phase I-II study was to evaluate the toxicity and efficacy of {sup 177}Lu-DOTATATE in multiple cycles. Fifty-one consecutive patients with unresectable/metastatic sst{sub 2}-positive tumours, divided into two groups, received escalating activities (3.7-5.18 GBq/cycle, group 1; 5.18-7.4 GBq/cycle, group 2) of {sup 177}Lu-DOTATATE. Cumulative activities ranged from 3.7 to 29.2 GBq (median 26.4 GBq in median 6 cycles, group 1, 21 patients) and 5.55 to 28.9 GBq (median 25.2 GBq in 4 cycles, group 2, 30 patients), based on dosimetry. No major acute or delayed renal or haematological toxicity occurred (one grade 3 leukopenia and thrombocytopenia). Cumulative renal absorbed doses were 8-37 Gy (9-41 Gy bioeffective doses). A median decrease of creatinine clearance of 21.7% 6 months after PRRT, 23.9% after 1 year and 27.6% after 2 years was observed. Higher losses (>20%) occurred in patients with risk factors for renal toxicity, particularly hypertension and diabetes. Cumulative bone marrow doses were <1.5 Gy. Blood elements showed a progressive mild drop during cycles and recovered during follow-up (median 30 months). Thirty-nine patients were progressive at enrolment. Partial and complete responses occurred in 15 of 46 (32.6%) assessable patients. The median time to progression was 36 months. Overall survival was 68% at 36 months. Non-responders and patients with extensive tumour involvement had lower survival. {sup 177}Lu-DOTATATE was well tolerated up to 29 GBq cumulative activity (up to 7.4 GBq/cycle). The maximum tolerated dose/cycle was not reached. However, considering the individual bone marrow function and the presence of risk factors for kidney toxicity, it seems safer to divide cumulative activities into lower activity cycles. (orig.)

  1. Characterization of a naturally-occurring polymorphism in the UHR-1 gene encoding the putative rat prolactin-releasing peptide receptor.

    Science.gov (United States)

    Ellacott, Kate L J; Donald, Emma L; Clarkson, Paul; Morten, John; Masters, Dave; Brennand, John; Luckman, Simon M

    2005-04-01

    The rat orphan receptor UHR-1 and its human orthologue, GPR10, were first isolated in 1995. The ligand for this receptor, prolactin-releasing peptide (PrRP), was identified in 1998 by reverse pharmacology and has subsequently been implicated in a number of physiological processes. As supported by its localization and regulation in the hypothalamus and brainstem, we have shown previously that PrRP is involved in energy homeostasis. Here we describe a naturally occurring polymorphism in the UHR-1 gene that results in an ATG to ATA change at the putative translational initiation site. The presence of the polymorphism abolished the binding of 125I PrRP in rat brain slices but did not affect the ability of PrRP to reduce fast-induced food intake. Together this data suggest that PrRP may be exerting its feeding effects through a receptor other than UHR-1.

  2. An epirubicin-peptide conjugate with anticancer activity is dependent upon the expression level of the surface transferrin receptor.

    Science.gov (United States)

    Yang, Jiadan; Yang, Qiyu; Xu, Lu; Lou, Jie; Dong, Zhi

    2017-01-01

    Epirubicin (EPI) is one of the most widely used anticarcinogens; however, serious side effects, including cardiomyopathy and congestive heart failure, limit its long‑term administration. To overcome this problem, the HAIYPRH peptide ligand was used with EPI in the synthesis of a HAIYPRH‑EPI conjugate. The anticancer activity and cellular uptake of the conjugate were measured and evaluated. The results of the present study indicated that the cytotoxicity of HAIYPRH‑EPI was correlated with the expression of the cell surface transferrin receptor (TfR). The conjugate exerted high cytotoxicity and proapoptotic function when in an LN229 glioma cell line, which overexpresses surface TfR. It was hypothesized that transferrin (Tf) can promote cytotoxicity. Conversely, the conjugate exhibited very low cytotoxicity and proapoptotic function in a U87 glioma cell line, in which surface TfR expression was undetectable. In addition, fluorescence microscopy and flow cytometry methods were used to evaluate cellular uptake, and the results of these methods were consistent with the present hypotheses. The conjugate cellular uptake of the conjugate in LN229 cells was markedly higher compared with that in U87 cells, and it was hypothesized that Tf can enhance the uptake in LN229 cells. The cytotoxicity of HAIYPRH‑EPI was dependent upon the expression of surface TfR. Considering that the majority of cancer cells have high rates of iron uptake and surface TfR is generally overexpressed on cancer cells, it was speculated by the authors that HAIYPRH‑EPI may form part of an effective strategy for increasing the selectivity of EPI for cancer cells, as well as reducing its systemic toxicity. To confirm the hypothesis, the effects of HAIYPRH‑EPI on non‑cancerous cell lines were investigated. A future study will examine the side effects of HAIYPRH‑EPI, using a suitable delivery system in an animal model.

  3. Inflammation and N-formyl peptide receptors mediate the angiogenic activity of human vitreous humour in proliferative diabetic retinopathy.

    Science.gov (United States)

    Rezzola, Sara; Corsini, Michela; Chiodelli, Paola; Cancarini, Anna; Nawaz, Imtiaz M; Coltrini, Daniela; Mitola, Stefania; Ronca, Roberto; Belleri, Mirella; Lista, Liliana; Rusciano, Dario; De Rosa, Mario; Pavone, Vincenzo; Semeraro, Francesco; Presta, Marco

    2017-04-01

    Angiogenesis and inflammation characterise proliferative diabetic retinopathy (PDR), a major complication of diabetes mellitus. However, the impact of inflammation on the pathogenesis of PDR neovascularisation has not been elucidated. Here, we assessed the capacity of PDR vitreous fluid to induce pro-angiogenic/proinflammatory responses in endothelium and the contribution of the inflammation-related pattern recognition N-formyl peptide receptors (FPRs) in mediating these responses. Pooled and individual pars plana vitrectomy-derived PDR vitreous fluid ('PDR vitreous') samples were assessed in endothelial cell proliferation, motility, sprouting and morphogenesis assays, and for the capacity to induce proinflammatory transcription factor activation, reactive oxygen species production, intercellular junction disruption and leucocyte-adhesion molecule upregulation in these cells. In vivo, the pro-angiogenic/proinflammatory activity of PDR vitreous was tested in murine Matrigel plug and chick embryo chorioallantoic membrane (CAM) assays. Finally, the FPR inhibitors Boc-Phe-Leu-Phe-Leu-Phe (Boc-FLFLF) and Ac-L-Arg-Aib-L-Arg-L-Cα(Me)Phe-NH2 tetrapeptide (UPARANT) were evaluated for their capacity to affect the biological responses elicited by PDR vitreous. PDR vitreous activates a pro-angiogenic/proinflammatory phenotype in endothelial cells. Accordingly, PDR vitreous triggers a potent angiogenic/inflammatory response in vivo. Notably, the different capacity of individual PDR vitreous samples to induce neovessel formation in the CAM correlates with their ability to recruit infiltrating CD45+ cells. Finally, the FPR inhibitor Boc-FLFLF and the novel FPR antagonist UPARANT inhibit neovessel formation and inflammatory responses triggered by PDR vitreous in the CAM assay. This study provides evidence that inflammation mediates the angiogenic activity of PDR vitreous and paves the way for the development of FPR-targeting anti-inflammatory/anti-angiogenic approaches for PDR

  4. [ASSOCIATION OF CYCLIC CITRULLINATED PEPTIDE ANTIBODIES LEVEL WITH RHEUMATOID ARTHRITIS ACTIVITY BASED ON GLUCOCORTICOID RECEPTOR GENE BBL1 POLYMORPHISM].

    Science.gov (United States)

    Prystupa, L; Savchenko, O; Koroza, S

    2015-10-01

    The ambiguity of facts on connection between glucocorticoid receptor gene (GR) Bcl1 polymorphism in rheumatoid arthritis (RA) and its activity as well as lack of facts on its association with serological variants of the desease, makes ir reasonable to investigate its connections between cyclic citrullinated peptide antibodiss (ACCP) concentration and clinico-laboratorial parameters of RA (DAS 28 desease activity score, C-reactive protein concentration (CRP) and erythrocyte sedimentation rate (ESR) level based on GR gene Bcl1 polymorphism. Study involved 161 RA patients aged over 40 as well as 96 healthy individuals. Routine examination of RA diagnostics, anthropometric and molecular genetic methods were used in the research. Statistical analysis of the results was performed using SPSS-17 program. It has been proved that there is no significant difference in GR gene Bcl1 polymorphism distribution based on DAS 28 RA desease activity score, ACCP concentration and ESR level. However, we have found out that G/G genotype bearers have positive correlation relationship between ACCP titre and RA activity by laboratorial parameters (CRP, ESR),DAS 28 score and rheumatoid factor (RF) which has not been found in C/C and C/G genotype bearing patients. The above indicates the association of G/G genotype by GR gene Bcl1 polymorphism with clinico-laboratorial parameters of RA inflammatory activity. In course of the study we have identified the existance of correlation relationship between ACCP concentration and DAS 28 score of RA activity, CRP concentration and ESR level in individuals bearing G/G gene by GR gene Bcl11 polymorphism gene. The association between GR gene Bcl1 polymorphism and clinico-laboratorial parameters of RA inflammatory activity has not been found.

  5. A peptide derived from the CD loop-D helix region of ciliary neurotrophic factor (CNTF) induces neuronal differentiation and survival by binding to the leukemia inhibitory factor (LIF) receptor and common cytokine receptor chain gp130.

    Science.gov (United States)

    Rathje, Mette; Pankratova, Stanislava; Nielsen, Janne; Gotfryd, Kamil; Bock, Elisabeth; Berezin, Vladimir

    2011-12-01

    Ciliary neurotrophic factor (CNTF) induces neuronal differentiation and promotes the survival of various neuronal cell types by binding to a receptor complex formed by CNTF receptor α (CNTFRα), gp130, and the leukemia inhibitory factor (LIF) receptor (LIFR). The CD loop-D helix region of CNTF has been suggested to be important for the cytokine interaction with LIFR. We designed a peptide, termed cintrofin, that encompasses this region. Surface plasmon resonance analysis demonstrated that cintrofin bound to LIFR and gp130, but not to CNTFRα, with apparent KD values of 35 nM and 1.1 nM, respectively. Cintrofin promoted the survival of cerebellar granule neurons (CGNs), in which cell death was induced either by potassium withdrawal or H2O2 treatment. Cintrofin induced neurite outgrowth from CGNs, and this effect was inhibited by specific antibodies against both gp130 and LIFR, indicating that these receptors are involved in the effects of cintrofin. The C-terminal part of the peptide, corresponding to the D helix region of CNTF, was shown to be essential for the neuritogenic action of the peptide. CNTF and LIF induced neurite outgrowth in CGNs plated on laminin-coated slides. On uncoated slides, CNTF and LIF had no neuritogenic effect but were able to inhibit cintrofin-induced neuronal differentiation, indicating that cintrofin and cytokines compete for the same receptors. In addition, cintrofin induced the phosphorylation of STAT3, Akt, and ERK, indicating that it exerts cell signaling properties similar to those induced by CNTF and may be a valuable survival agent with possible therapeutic potential. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Exacerbation of collagen induced arthritis by Fcγ receptor targeted collagen peptide due to enhanced inflammatory chemokine and cytokine production

    Directory of Open Access Journals (Sweden)

    Szarka E

    2012-04-01

    Full Text Available Eszter Szarka1*, Zsuzsa Neer1*, Péter Balogh2, Monika Ádori1, Adrienn Angyal1, József Prechl3, Endre Kiss1,3, Dorottya Kövesdi1, Gabriella Sármay11Department of Immunology, Eötvös Loránd University, 1117 Budapest, 2Department of Immunology and Biotechnology, University of Pécs, Pécs, 3Immunology Research Group of the Hungarian Academy of Science at Eötvös Loránd University, 1117 Budapest, Hungary*These authors contributed equally to this workAbstract: Antibodies specific for bovine type II collagen (CII and Fcγ receptors play a major role in collagen-induced arthritis (CIA, a mouse model of rheumatoid arthritis (RA. Our aim was to clarify the mechanism of immune complex-mediated inflammation and modulation of the disease. CII pre-immunized DBA/1 mice were intravenously boosted with extravidin coupled biotinylated monomeric CII-peptide epitope (ARGLTGRPGDA and its complexes with biotinylated FcγRII/III specific single chain Fv (scFv fragment. Disease scores were monitored, antibody titers and cytokines were determined by ELISA, and binding of complexes was detected by flow cytometry and immune histochemistry. Cytokine and chemokine secretion was monitored by protein profiler microarray. When intravenously administered into collagen-primed DBA/1 mice, both CII-peptide and its complex with 2.4G2 scFv significantly accelerated CIA and increased the severity of the disease, whereas the monomeric peptide and monomeric 2.4G2 scFv had no effect. FcγRII/III targeted CII-peptide complexes bound to marginal zone macrophages and dendritic cells, and significantly elevated the synthesis of peptide-specific IgG2a. Furthermore, CII-peptide containing complexes augmented the in vivo secretion of cytokines, including IL-10, IL-12, IL-17, IL-23, and chemokines (CXCL13, MIP-1, MIP-2. These data indicate that complexes formed by the CII-peptide epitope aggravate CIA by inducing the secretion of chemokines and the IL-12/23 family of pro

  7. Exenatide upregulates gene expression of glucagon-like peptide-1 receptor and nerve growth factor in streptozotocin/nicotinamide-induced diabetic mice.

    Science.gov (United States)

    Gumuslu, Esen; Cine, Naci; Ertan, Merve; Mutlu, Oguz; Komsuoglu Celikyurt, Ipek; Ulak, Guner

    2017-11-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone that has modulating effects on insulin release. GLP-1 and receptors for GLP-1 are widely expressed throughout the body including the brain. The expression of GLP-1 receptors is very specific to large neurons in hippocampus, neocortex, and cerebellum. GLP-1 receptor stimulation enhances glucose-dependent insulin secretion and lowers blood glucose in type 2 diabetes mellitus. Studies on adipobiology of neurotrophins have focused on nerve growth factor (NGF) as an example of adipose-derived neurotrophins. Compromised trophic factor signaling may underlie neurodegenerative diseases ranging from Alzheimer's disease to diabetic neuropathies. Exenatide, a potent and selective agonist for the GLP-1 receptor, is currently approved for the treatment of type 2 diabetes mellitus. The aim of this study was to assess the effect of chronic exenatide treatment on the hippocampal gene expression levels of GLP-1 receptor and NGF in diabetic mice. The effects of chronic exenatide treatment (0.1 μg/kg, s.c., twice daily for 2 weeks) on GLP-1 receptor and NGF gene expression levels in the hippocampus of streptozotocin/nicotinamide (STZ-NA)-induced diabetic mice were assessed by quantitative real-time polymerase chain reaction (RT-PCR). The results of this study revealed that hippocampal gene expression of GLP-1 receptor and NGF were downregulated in diabetic mice. Importantly, a significant increase in the gene expression level of GLP-1 receptor and NGF was determined after 2 weeks of exenatide administration. Increased gene expression level of GLP-1 receptor and NGF may underlie the beneficial action of exenatide in STZ/NA-induced diabetes. © 2017 Société Française de Pharmacologie et de Thérapeutique.

  8. Prognostic implications of parathyroid hormone-related protein in males and females with non--small-cell lung cancer.

    Science.gov (United States)

    Montgrain, Philippe R; Deftos, Leonard J; Arenberg, Douglas; Tipps, Ann; Quintana, Rick; Carskadon, Shannon; Hastings, Randolph H

    2011-05-01

    Non-small-cell lung carcinoma immunoreactivity for parathyroid hormone-related protein has been associated with increased survival in female patients but not in male patients. The current investigation attempted to substantiate this finding in 2 new patient groups. Patients were divided into groups with and without immunoreactivity for a carboxyl-terminal parathyroid hormone-related protein epitope assessed in deparaffinized sections by a blinded observer. One group included 85 female patients with stage I lung cancer, and the second group had 48 female and 66 male patients with stage I-IV lung cancer. Survival times were compared by the log-rank test between groups separated by tumor parathyroid hormone-related protein status. Parathyroid hormone-related protein was present in 70%-80% of the patients, independent of sex, stage, and smoking history. In the females with stage I lung cancer, parathyroid hormone-related protein increased median survival from 25 to 60 months (P < .05). In the second group, parathyroid hormone-related protein expression increased 48-month disease-free survival of female lung cancer patients from 44% to 63% (P < .05), but had no effect in male patients. Parathyroid hormone-related protein remained a significant, independent predictor when evaluated together with other covariates by Cox multivariate regression. This study verifies that parathyroid hormone-related protein is a sex-dependent survival factor for non-small-cell lung carcinoma, that it correlates with disease-free survival, and that the association with survival holds for women with early-stage disease as well as more advanced cancer. Thus, the protein could find use as a prognostic indicator and could be a target for therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. The Neuroprotective Peptide Poly-Arginine-12 (R12) Reduces Cell Surface Levels of NMDA NR2B Receptor Subunit in Cortical Neurons; Investigation into the Involvement of Endocytic Mechanisms.

    Science.gov (United States)

    MacDougall, Gabriella; Anderton, Ryan S; Edwards, Adam B; Knuckey, Neville W; Meloni, Bruno P

    2017-02-01

    We have previously reported that cationic poly-arginine and arginine-rich cell-penetrating peptides display high-level neuroprotection and reduce calcium influx following in vitro excitotoxicity, as well as reduce brain injury in animal stroke models. Using the neuroprotective peptides poly-arginine R12 (R12) and the NR2B9c peptide fused to the arginine-rich carrier peptide TAT (TAT-NR2B9c; also known as NA-1), we investigated the mechanisms whereby poly-arginine and arginine-rich peptides reduce glutamate-induced excitotoxic calcium influx. Using cell surface biotin protein labeling and western blot analysis, we demonstrated that R12 and TAT-NR2B9c significantly reduced cortical neuronal cell surface expression of the NMDA receptor subunit NR2B. Chemical endocytic inhibitors used individually or in combination prior to glutamate excitotoxicity did not significantly affect R12 peptide neuroprotective efficacy. Similarly, pretreatment of neurons with enzymes to degrade anionic cell surface proteoglycans, heparan sulfate proteoglycan (HSPG), and chondroitin sulfate proteoglycan (CSPG), as well as sialic acid residues, did not significantly affect peptide neuroprotective efficacy. While the exact mechanisms responsible for R12 peptide-mediated NMDA receptor NR2B subunit cell surface downregulation were not identified, an endocytic process could not be ruled out. The study supports our hypothesis that arginine-rich peptides reduce excitotoxic calcium influx by reducing the levels of cell surface ion channels.

  10. Guideline for PET/CT imaging of neuroendocrine neoplasms with {sup 68}Ga-DOTA-conjugated somatostatin receptor targeting peptides and {sup 18}F-DOPA

    Energy Technology Data Exchange (ETDEWEB)

    Bozkurt, Murat Fani [Hacettepe University Faculty of Medicine Department of Nuclear Medicine, Ankara (Turkey); Virgolini, Irene; Decristoforo, Clemens [Medical University Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Balogova, Sona [Comenius University and St. Elisabeth Oncology Institute, Department of Nuclear Medicine, Bratislava (Slovakia); Tenon Hospital AP-HP and Universite Pierre et Marie Curie, Department of Nuclear Medicine, Paris (France); Beheshti, Mohsen [St. Vincent' s Hospital, PET-CT Center, Department of Nuclear Medicine and Endocrinology, Linz (Austria); Paracelsus Medical University, Department of Nuclear Medicine, Salzburg (Austria); Rubello, Domenico [Santa Maria della Misericordia Hospital, Department of Nuclear Medicine, PET Center and Medical Physics and Radiology, Rovigo (Italy); Ambrosini, Valentina; Fanti, Stefano [University of Bologna, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Bologna (Italy); Kjaer, Andreas [National University Hospital and University of Copenhagen, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Delgado-Bolton, Roberto [San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, Logrono (Spain); Kunikowska, Jolanta [Medical University of Warsaw, Nuclear Medicine, Warsaw (Poland); Oyen, Wim J.G. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London (United Kingdom); Chiti, Arturo [Humanitas University, Nuclear Medicine Department, Rozzano, MI (Italy); Giammarile, Francesco [University of Lyon, Nuclear Medicine, Lyon (France)

    2017-08-15

    Neuroendocrine neoplasms are a heterogenous group of tumours, for which nuclear medicine plays an important role in the diagnostic work-up as well as in the targeted therapeutic options. This guideline is aimed to assist nuclear medicine physicians in recommending, performing, reporting and interpreting the results of somatostatin receptor (SSTR) PET/CT imaging using {sup 68}Ga-DOTA-conjugated peptides, as well as {sup 18}F-DOPA imaging for various neuroendocrine neoplasms. The previous procedural guideline by EANM regarding the use PET/CT tumour imaging with {sup 68}Ga-conjugated peptides has been revised and updated with the relevant and recent literature in the field with contribution of distinguished experts. (orig.)

  11. NCAM-mimetic, FGL peptide, restores disrupted fibroblast growth factor receptor (FGFR) phosphorylation and FGFR mediated signaling in neural cell adhesion molecule (NCAM)-deficient mice

    DEFF Research Database (Denmark)

    Aonurm-Helm, Anu; Berezin, Vladimir; Bock, Elisabeth

    2010-01-01

    ), a member of Src family of tyrosine kinases, Fyn and Raf1 kinase which all activate different intracellular signaling pathways. The objective was to clarify, which signaling pathways are being disrupted in NCAM knockout mice and whether FGL peptide is able to restore observed disruptions. Therefore we...... in all isoforms of NCAM have decreased basal phosphorylation levels of FGFR1 and CaMKII and CaMKIV. Furthermore, NCAM-mimetic, FGL peptide, is found to be able to restore FGFR1, CaMKII and CaMKIV phosphorylation levels and thereby mimic the interactions of NCAM at this receptor in NCAM deficient mice....... Also, we found that Fyn(Tyr530), Raf1, MAP kinases and Akt kinase phosphorylation in adult animals is not affected by NCAM deficiency but interestingly, we found an over-expression of another cell adhesion molecule L1. We conclude that in NCAM deficient mice FGFR1-dependent signaling is disrupted...

  12. Structure-activity relationship study towards non-peptidic positron emission tomography (PET) radiotracer for gastrin releasing peptide receptors : Development of [F-18] (S)-3-(1H-indol-3-yl)-N-[1-[5-(2-fluoroethoxy) pyridin-2-yl]cyclohexylmethyl]-2-methyl-2-[3-(4-nitrophenyl)ureido]propionamide

    NARCIS (Netherlands)

    Lacivita, Enza; Lucente, Ermelinda; Kwizera, Chantal; Farinha Antunes, Ines; Niso, Mauro; De Giorgio, Paola; Perrone, Roberto; Colabufo, Nicola A.; Elsinga, Philip H.; Leopoldo, Marcello

    2017-01-01

    Gastrin-releasing peptide receptors (GRP-Rs, also known as bombesin 2 receptors) are overexpressed in a variety of human cancers, including prostate cancer, and therefore they represent a promising target for in vivo imaging of tumors using positron emission tomography (PET). Structural

  13. DynaDom: structure-based prediction of T cell receptor inter-domain and T cell receptor-peptide-MHC (class I) association angles.

    Science.gov (United States)

    Hoffmann, Thomas; Marion, Antoine; Antes, Iris

    2017-02-02

    T cell receptor (TCR) molecules are involved in the adaptive immune response as they distinguish between self- and foreign-peptides, presented in major histocompatibility complex molecules (pMHC). Former studies showed that the association angles of the TCR variable domains (Vα/Vβ) can differ significantly and change upon binding to the pMHC complex. These changes can be described as a rotation of the domains around a general Center of Rotation, characterized by the interaction of two highly conserved glutamine residues. We developed a computational method, DynaDom, for the prediction of TCR Vα/Vβ inter-domain and TCR/pMHC orientations in TCRpMHC complexes, which allows predicting the orientation of multiple protein-domains. In addition, we implemented a new approach to predict the correct orientation of the carboxamide endgroups in glutamine and asparagine residues, which can also be used as an external, independent tool. The approach was evaluated for the remodeling of 75 and 53 experimental structures of TCR and TCRpMHC (class I) complexes, respectively. We show that the DynaDom method predicts the correct orientation of the TCR Vα/Vβ angles in 96 and 89% of the cases, for the poses with the best RMSD and best interaction energy, respectively. For the concurrent prediction of the TCR Vα/Vβ and pMHC orientations, the respective rates reached 74 and 72%. Through an exhaustive analysis, we could show that the pMHC placement can be further improved by a straightforward, yet very time intensive extension of the current approach. The results obtained in the present remodeling study prove the suitability of our approach for interdomain-angle optimization. In addition, the high prediction rate obtained specifically for the energetically highest ranked poses further demonstrates that our method is a powerful candidate for blind prediction. Therefore it should be well suited as part of any accurate atomistic modeling pipeline for TCRpMHC complexes and potentially

  14. 6-Methyl-2,4-Disubstituted Pyridazin-3(2H)-ones: A Novel Class of Small-Molecule Agonists for Formyl Peptide Receptors

    Science.gov (United States)

    Cilibrizzi, Agostino; Quinn, Mark T.; Kirpotina, Liliya N.; Schepetkin, Igor A; Holderness, Jeff; Ye, Richard D.; Rabiet, Marie-Josephe; Biancalani, Claudio; Cesari, Nicoletta; Graziano, Alessia; Vergelli, Claudia; Pieretti, Stefano; Piaz, Vittorio Dal; Giovannoni, Maria Paola

    2010-01-01

    Following a ligand-based drug design approach, a potent mixed formyl peptide receptor 1 (FPR1) and formyl peptide receptor-like 1 (FPRL1) agonist (14a) and a potent and specific FPRL1 agonist (14x) were identified. These compounds belong to a large series of pyridazin-3(2H)-one derivatives substituted with a methyl group at position 6 and a methoxy benzyl at position 4. At position 2, an acetamide side chain is essential for activity. Likewise, the presence of lipophilic and/or electronegative substituents in the position para to the aryl group at the end of the chain plays a critical role for activity. Affinity for FPR1 receptors was evaluated by measuring intracellular calcium flux in HL-60 cells transfected with FPR1, FPRL1, and FPRL2. Agonists were able to activate intracellular calcium mobilization and chemotaxis in human neutrophils. The most potent chemotactic agent (EC50 = 0.6 μM) was the mixed FPR/FPRL1 agonist 14h. PMID:19639995

  15. Conservation of the abscission signaling peptide IDA during Angiosperm evolution: withstanding genome duplications and gain and loss of the receptors HAE/HSL2.

    Science.gov (United States)

    Stø, Ida M; Orr, Russell J S; Fooyontphanich, Kim; Jin, Xu; Knutsen, Jonfinn M B; Fischer, Urs; Tranbarger, Timothy J; Nordal, Inger; Aalen, Reidunn B

    2015-01-01

    The peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LIKE2 (HSL2), controls different cell separation events in Arabidopsis thaliana. We hypothesize the involvement of this signaling module in abscission processes in other plant species even though they may shed other organs than A. thaliana. As the first step toward testing this hypothesis from an evolutionarily perspective we have identified genes encoding putative orthologs of IDA and its receptors by BLAST searches of publically available protein, nucleotide and genome databases for angiosperms. Genes encoding IDA or IDA-LIKE (IDL) peptides and HSL proteins were found in all investigated species, which were selected as to represent each angiosperm order with available genomic sequences. The 12 amino acids representing the bioactive peptide in A. thaliana have virtually been unchanged throughout the evolution of the angiosperms; however, the number of IDL and HSL genes varies between different orders and species. The phylogenetic analyses suggest that IDA, HSL2, and the related HSL1 gene, were present in the species that gave rise to the angiosperms. HAE has arisen from HSL1 after a genome duplication that took place after the monocot-eudicots split. HSL1 has also independently been duplicated in the monocots, while HSL2 has been lost in gingers (Zingiberales) and grasses (Poales). IDA has been duplicated in eudicots to give rise to functionally divergent IDL peptides. We postulate that the high number of IDL homologs present in the core eudicots is a result of multiple whole genome duplications (WGD). We substantiate the involvement of IDA and HAE/HSL2 homologs in abscission by providing gene expression data of different organ separation events from various species.

  16. Parathyroid Hormone-Related Peptide (PTHrP) as a New Target for Metastatic Breast Cancer: Evaluation in Preclinical Models

    Science.gov (United States)

    2016-10-01

    against this notoriously hard- to-treat family of cancers. We have now constructed animal models with mammary epithelium fluorescent labelled cells to...monoclonal antibodies against breast cancer is likely to be transferable to other pathologies where PTHrP is part of the driving mechanisms. The...Nearest person month worked 12 Contribution to project Construction of TdT animals, CRISPr preparation of human TNBC KO lines, student mentoring

  17. Expression analyses of insulin-like peptide 3, RXFP2, LH receptor, and 3β-hydroxysteroid dehydrogenase in testes of normal and cryptorchid dogs.

    Science.gov (United States)

    Hannan, M A; Kawate, N; Kubo, Y; Pathirana, I N; Büllesbach, E E; Hatoya, S; Inaba, T; Takahashi, M; Tamada, H

    2015-10-15

    Insulin-like peptide 3 (INSL3) plays a key role in testicular descent in rodents, whereas in domestic animals, many aspects of the roles of INSL3 in reproductive organs after puberty are still unknown. This study was undertaken to (1) determine the quantitative changes of gene expression of testicular INSL3, its receptor (RXFP2), LH receptor, and 3β-hydroxysteroid dehydrogenase during and after puberty in normal male dogs; (2) compare the expressions of these substances in normal and cryptorchid dogs; and (3) localize the cells expressing INSL3 in normal and retained canine testes. Testes were obtained from small-breed normal male dogs (n = 56) and cryptorchid dogs (n = 22). Normal scrotal testes from the normal dogs (normal testes), retained testes from both the unilateral and bilateral cryptorchid dogs (retained testes), and scrotal testes of the unilateral cryptorchid dogs (cryptorchid scrotal testes) were used. We measured the concentrations of these testicular messenger RNAs (mRNAs) by quantitative real-time reverse transcription polymerase chain reaction, and an enzyme immunoassay was used for measuring INSL3 peptide. Immunohistochemistry for INSL3 peptide was done in paraformaldehyde-fixed frozen testicular tissue. In the normal dogs, total amount of INSL3 mRNA per testis tended to decrease (P = 0.05) from pubertal (6-12 months) to postpubertal (1-5 years) and decreased (P testes than those in the normal testes and cryptorchid scrotal testes, and similar differences were observed for INSL3 peptide. Reversely, total amounts of INSL3 mRNA and peptide per retained testis were lower (P testes. Concentrations and total amount of RXFP2 mRNA in the retained testes were almost nil and lower (P testes and in the cryptorchid scrotal testes. Total amount of LH receptor mRNA per retained testis was lower (P testes. These results suggest that INSL3 in retained testes of cryptorchid dogs is substantially expressed per unit-weight basis but may be produced with lower

  18. Mechanism study of peptide GMBP1 and its receptor GRP78 in modulating gastric cancer MDR by iTRAQ-based proteomic analysis.

    Science.gov (United States)

    Wang, Xiaojuan; Li, Yani; Xu, Guanghui; Liu, Muhan; Xue, Lin; Liu, Lijuan; Hu, Sijun; Zhang, Ying; Nie, Yongzhan; Liang, Shuhui; Wang, Biaoluo; Ding, Jie

    2015-05-06

    Multidrug resistance (MDR) is a major obstacle to the treatment of gastric cancer (GC). Using a phage display approach, we previously obtained the peptide GMBP1, which specifically binds to the surface of MDR gastric cancer cells and is subsequently internalized. Furthermore, GMBP1 was shown to have the potential to reverse the MDR phenotype of gastric cancer cells, and GRP78 was identified as the receptor for this peptide. The present study aimed to investigate the mechanism of peptide GMBP1 and its receptor GRP78 in modulating gastric cancer MDR. Fluorescence-activated cell sorting (FACS) and immunofluorescence staining were used to investigate the subcellular location and mechanism of GMBP1 internalization. iTRAQ was used to identify the MDR-associated downstream targets of GMBP1. Differentially expressed proteins were identified in GMBP1-treated compared to untreated SGC7901/ADR and SGC7901/VCR cells. GO and KEGG pathway analyses of the differentially expressed proteins revealed the interconnection of these proteins, the majority of which are involved in MDR. Two differentially expressed proteins were selected and validated by western blotting. GMBP1 and its receptor GRP78 were found to be localized in the cytoplasm of GC cells, and GRP78 can mediate the internalization of GMBP1 into MDR cells through the transferrin-related pathway. In total, 3,752 and 3,749 proteins were affected in GMBP1-treated SGC7901/ADR and SGC7901/VCR cells, respectively, involving 38 and 79 KEGG pathways. Two differentially expressed proteins, CTBP2 and EIF4E, were selected and validated by western blotting. This study explored the role and downstream mechanism of GMBP1 in GC MDR, providing insight into the role of endoplasmic reticulum stress protein GRP78 in the MDR of cancer cells.

  19. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans.

    Science.gov (United States)

    van Bloemendaal, L; Veltman, D J; Ten Kulve, J S; Groot, P F C; Ruhé, H G; Barkhof, F; Sloan, J H; Diamant, M; Ijzerman, R G

    2015-09-01

    To test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. As part of a larger study, we determined the effects of GLP-1 receptor activation on brain responses to anticipation and receipt of chocolate milk versus a tasteless solution, using functional MRI (fMRI). Obese subjects with type 2 diabetes, and obese and lean subjects with normoglycaemia (n = 48) underwent three fMRI sessions at separate visits with intravenous infusion of the GLP-1 receptor agonist exenatide, exenatide with prior GLP-1 receptor blockade by exendin-9-39 or placebo, during somatostatin pituitary-pancreatic clamps. Body mass index negatively correlated with brain responses to receipt of chocolate milk and positively correlated with anticipation of receipt of chocolate milk in brain areas regulating reward, appetite and motivation. Exenatide increased brain responses to receipt of chocolate milk and decreased anticipation of receipt of chocolate milk compared with placebo, paralleled by reductions in food intake. Exendin-9-39 largely prevented these effects. Our findings show that GLP-1 receptor activation decreases anticipatory food reward, which may reduce cravings for food and increases consummatory food reward, which may prevent overeating. © 2015 John Wiley & Sons Ltd.

  20. [Impact of anti-diabetic therapy based on glucagon-like peptide-1 receptor agonists on the cardiovascular risk of patients with type 2 diabetes mellitus].

    Science.gov (United States)

    Camafort-Babkowski, Miguel

    2013-08-17

    Anti-diabetic drugs have, in addition to their well-known glucose lowering-effect, different effects in the rest of cardiovascular factors that are associated with diabetes mellitus. Glucagon-like peptide-1 (GLP-1) receptor agonists have recently been incorporated to the therapeutic arsenal of type 2 diabetes mellitus. The objective of this review is to summarize the available evidence on the effect of the GLP-1 receptor agonists on different cardiovascular risk factors, mediated by the effect of GLP-1 receptor agonists on the control of hyperglycaemia and the GLP-1 receptor agonists effect on other cardiovascular risk factors (weight control, blood pressure control, lipid profile and all other cardiovascular risk biomarkers). In addition, we present the emerging evidence with regards to the impact that GLP-1 receptor agonists therapy could have in the reduction of cardiovascular events and the currently ongoing studies addressing this issue. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  1. Incretin-based treatment of type 2 diabetes: glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors

    DEFF Research Database (Denmark)

    Deacon, Carolyn F

    2007-01-01

    Incretins are gut peptides that potentiate nutrient-stimulated insulin secretion following meal ingestion. Activities of the dominant incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide, include glucose-dependent stimulation of insulin secretion and, in preclin...... and liraglutide) and DPP-4 inhibitors that act to increase concentrations of endogenous intact incretins (e.g. sitagliptin and vildagliptin). Clinical trials of these incretin-based therapies have shown them to be effective in improving glycaemic control in patients with T2DM....

  2. A study of CDR3 loop dynamics reveals distinct mechanisms of peptide recognition by T-cell receptors exhibiting different levels of cross-reactivity.

    Science.gov (United States)

    Tsuchiya, Yuko; Namiuchi, Yoshiki; Wako, Hiroshi; Tsurui, Hiromichi

    2017-10-09

    T-cell receptors (TCRs) can productively interact with many different peptides bound within the MHC binding groove. This property varies with the level of cross-reactivity of TCRs; some TCRs are particularly hyper cross-reactive while others exhibit greater specificity. To elucidate the mechanism behind these differences, we studied five TCRs in complex with the same class II MHC (1A b )-peptide (3K), that are known to exhibit different levels of cross-reactivity. Although these complexes have similar binding affinities, the interface areas between the TCR and the peptide-MHC (pMHC) differ significantly. We investigated static and dynamic structural features of the TCR-pMHC complexes and of TCRs in a free state, as well as the relationship between binding affinity and interface area. It was found that the TCRs known to exhibit lower levels of cross-reactivity bound to pMHC using an induced-fitting mechanism, forming large and tight interfaces rich in specific hydrogen bonds. In contrast, TCRs known to exhibit high levels of cross-reactivity used a more rigid binding mechanism where non-specific π-interactions involving the bulky Trp residue in CDR3β dominated. As entropy loss upon binding in these highly degenerate and rigid TCRs is smaller than that in less degenerate TCRs, they can better tolerate changes in residues distal from the major contacts with MHC-bound peptide. Hence, our dynamics study revealed that differences in the peptide recognition mechanisms by TCRs appear to correlate with the levels of T-cell cross-reactivity. © 2017 John Wiley & Sons Ltd.

  3. Biodistribution on Tc-99m labeled somatostatin receptor-binding peptide (Depreotide, NeoTec) planar and SPECT studies

    Energy Technology Data Exchange (ETDEWEB)

    Shih, W; Hirschowitz, E.; Bensadoun, E.; Woodring, J.; Ryo, Y.U.; Kraman, S. [Kentucky Univ., Lexington, KY (United States). Medical Center

    2002-05-01

    The purpose of this study was to determine the biodistribution of Tc-99m labeled somatostatin receptor-binding peptide (Depreotide) on planar and SPECT studies of the thorax and upper abdomen in order to improve diagnostic accuracy. Retrospectively 29 planar and SPECT studies from 28 patients (all males, average age of 65.79) were reviewed. All the patients had been referred for evaluation of solitary pulmonary nodules. Two to four hours after IV injection of 555- to 740-MBq (15-20 mCi) Tc-99m Depreotide, anterior and posterior total body images, and anterior, posterior, right lateral and left lateral planar images were obtained, and thoracic SPECT was acquired with a three-head gamma camera. The degree of uptake in the lungs, thoracic cage, and organs of the upper abdomen was rated from ''0'' to ''++++''. The range of normal activity in the thorax includes cardiac, ''0''; pulmonary, +''; rib, ''+/++''; sternum, ''++''; vertebrae, ''++''. The degree of normal activity seen in the upper abdominal organs includes liver and spleen, +++'', and kidneys, '''+++/++++''. Eight patients with emphysema had diffuse pulmonary uptake graded as ''+/++''. One patient with left pneumonectomy and radiation therapy to the left hemithorax had photon-deficiency in the left hemithorax and decreased to absent uptake including the vertebrae and ribs. Although some cases had background pulmonary uptake of Tc-99m Depreotide, the bone/bone marrow activity of the thoracic cage including the ribs, sternum, and thoracic spine is sufficiently great enough to produce a clear distinction between bone and lung in the thoracic cavity that gives high-contrast resolution on SPECT. The intensity of radioactivity in the sub-diaphragmatic organs such as the liver, spleen, and kidneys provides useful guidance for the

  4. Treatment Strategy for Type 2 Diabetes with Obesity: Focus on Glucagon-like Peptide-1 Receptor Agonists.

    Science.gov (United States)

    Ji, Qiuhe

    2017-06-01

    The progressive nature of type 2 diabetes mellitus (T2DM) calls for step-wise intensification of therapy for maintaining normal glycemic levels and lowering cardiovascular (CV) risk. Because obesity is a prominent risk factor and comorbidity of T2DM, it further elevates the CV risk in T2DM. Therefore, it is vital to manage weight, obesity, and glycemic parameters for effective T2DM management. Few oral antidiabetic drugs (sulfonylureas and thiazolidinediones) and insulin are not suitable for obese patients with T2DM because these drugs cause weight gain. The present review discusses the place of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in the treatment of obese patients with T2DM and the significance of these drugs in the prevention of future CV risk in patients with T2DM. A literature search of PubMed and EMBASE was conducted by using the search terms T2DM, GLP-1RAs, obesity, and cardiovascular complication. Randomized controlled trials measuring the effect of GLP-1RAs versus that of placebo on CV outcomes were included in the review. GLP-1RAs have emerged as a therapeutic alternative; these drugs exert their actions by providing glycemic control, improving insulin resistance and ö̇-cell function, and reducing weight. The risk of hypoglycemia with GLP-1RAs is minimal; however, GLP-1RAs are associated with gastrointestinal adverse events and raise concerns regarding pancreatitis. Combining GLP-1RAs with insulin analogues results in higher efficacy, a lowered insulin dose, and reduced insulin-related hypoglycemia and weight gain. Longer acting GLP-1RAs are also associated with improvement in medication adherence. Improvement in CV risk factors such as blood pressure and lipid profile further increases their usability for improving CV outcomes. Overall, the properties of GLP-1RAs make them suitable for combination with oral antidiabetic drugs in the early stages of T2DM and with insulins in the later stages for optimizing comprehensive management of the

  5. Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Leshuai W.; McMahon Tobin, Grainne A.; Rouse, Rodney L., E-mail: rodney.rouse@fda.hhs.gov

    2012-10-15

    The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling

  6. Cardiovascular Actions and Clinical Outcomes With Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors.

    Science.gov (United States)

    Nauck, Michael A; Meier, Juris J; Cavender, Matthew A; Abd El Aziz, Mirna; Drucker, Daniel J

    2017-08-29

    Potentiation of glucagon-like peptide-1 (GLP-1) action through selective GLP-1 receptor (GLP-1R) agonism or by prevention of enzymatic degradation by inhibition of dipeptidyl peptidase-4 (DPP-4) promotes glycemic reduction for the treatment of type 2 diabetes mellitus by glucose-dependent control of insulin and glucagon secretion. GLP-1R agonists also decelerate gastric emptying, reduce body weight by reduction of food intake and lower circulating lipoproteins, inflammation, and systolic blood pressure. Preclinical studies demonstrate that both GLP-1R agonists and DPP-4 inhibitors exhibit cardioprotective actions in animal models of myocardial ischemia and ventricular dysfunction through incompletely characterized mechanisms. The results of cardiovascular outcome trials in human subjects with type 2 diabetes mellitus and increased cardiovascular risk have demonstrated a cardiovascular benefit (significant reduction in time to first major adverse cardiovascular event) with the GLP-1R agonists liraglutide (LEADER trial [Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Ourcome Results], -13%) and semaglutide (SUSTAIN-6 trial [Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide], -24%). In contrast, cardiovascular outcome trials examining the safety of the shorter-acting GLP-1R agonist lixisenatide (ELIXA trial [Evaluation of Lixisenatide in Acute Coronary Syndrom]) and the DPP-4 inhibitors saxagliptin (SAVOR-TIMI 53 trial [Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53]), alogliptin (EXAMINE trial [Examination of Cardiovascular Outcomes With Alogliptin Versus Standard of Care in Patients With Type 2 Diabetes Mellitus and Acute Coronary Syndrome]), and sitagliptin (TECOS [Trial Evaluating Cardiovascular Outcomes With Sitagliptin]) found that these agents neither increased nor decreased cardiovascular events. Here we review the

  7. Accurate assessment of long-term nephrotoxicity after peptide receptor radionuclide therapy with {sup 177}Lu-octreotate

    Energy Technology Data Exchange (ETDEWEB)

    Sabet, Amir; Ezziddin, Khaled; Reichman, Karl; Haslerud, Torjan; Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen; Ezziddin, Samer [University Hospital Bonn, Department of Nuclear Medicine, Bonn (Germany); Pape, Ulrich-Frank [Charite, University Medicine Berlin, Campus Virchow Clinic, Department of Hepatology and Gastroenterology, Berlin (Germany); Nagarajah, James [University Hospital, Department of Nuclear Medicine, Essen (Germany)

    2014-03-15

    Renal radiation during peptide receptor radionuclide therapy (PRRT) may result in glomerular damage, a potential reduction of glomerular filtration rate (GFR) and ultimately lead to renal failure. While reported PRRT nephrotoxicity is limited to data derived from serum creatinine - allowing only approximate estimates of GFR - the aim of this study is to accurately determine PRRT-induced long-term changes of renal function and associated risk factors according to state-of-the-art GFR measurement. Nephrotoxicity was analysed using {sup 99m}Tc-diethylenetriaminepentaacetic acid (DTPA) clearance data of 74 consecutive patients with gastroenteropancreatic neuroendocrine tumours (GEP NET) undergoing PRRT with {sup 177}Lu-octreotate. The mean follow-up period was 21 months (range 12-50) with a median of five GFR measurements per patient. The change of GFR was analysed by linear curve fit. Potential risk factors including diabetes mellitus, arterial hypertension, previous chemotherapy, renal impairment at baseline and cumulative administered activity were analysed regarding potential impact on renal function loss. In addition, Common Terminology Criteria for Adverse Events (CTCAE) v3.0 were used to compare nephrotoxicity determined by {sup 99m}Tc-DTPA clearance versus serum creatinine. The alteration in GFR differed widely among the patients (mean -2.1 ± 13.1 ml/min/m{sup 2} per year, relative yearly reduction -1.8 ± 18.9 %). Fifteen patients (21 %) experienced a mild (2-10 ml/min/m{sup 2} per year) and 16 patients (22 %) a significant (>10 ml/min/m{sup 2} per year) decline of GFR following PRRT. However, 11 patients (15 %) showed an increase of >10 ml/min/m{sup 2} per year. Relevant nephrotoxicity according to CTCAE (grade ≥3) was observed in one patient (1.3 %) with arterial hypertension and history of chemotherapy. Nephrotoxicity according to serum creatinine was discordant to that defined by GFR in 15 % of the assessments and led to underestimation in 12 % of

  8. Characterization of liraglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist, in rat partial and full nigral 6-hydroxydopamine lesion models of Parkinson's disease

    DEFF Research Database (Denmark)

    Hansen, Henrik H; Fabricius, Katrine; Barkholt, Pernille

    2016-01-01

    Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, have been demonstrated to promote neuroprotection in the rat 6-hydroxydopamine (6-OHDA) neurotoxin model of Parkinson's disease (PD), a neurodegenerative disorder characterized by progressive nigrostriatal dopaminergic neuron loss...... injected into the right medial forebrain bundle (n=17-20 rats per experimental group). Six weeks after induction of a partial nigral dopaminergic lesion, vehicle or liraglutide was administered for four weeks. In the full lesion model, vehicle dosing or liraglutide treatment was applied for a total of six...

  9. ClEST cluster :Cl_singleton0133 [ClEST

    Lifescience Database Archive (English)

    Full Text Available Cl_singleton0133 parathyroid hormone parathyroid hormone-related peptide receptor-like Cimex lectularius...AT fb07063 1 PREDICTED: parathyroid hormone/parathyroid hormone-related peptide receptor-like [Bombus

  10. Induction of Anti-Tumor Immune Responses by Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE in a Murine Model of a Human Neuroendocrine Tumor

    Directory of Open Access Journals (Sweden)

    Michael Bzorek

    2013-10-01

    Full Text Available Peptide receptor radionuclide therapy (PRRT is a relatively new mode of internally targeted radiotherapy currently in clinical trials. In PRRT, ionizing radioisotopes conjugated to somatostatin analogues are targeted to neuroendocrine tumors (NETs via somatostatin receptors. Despite promising clinical results, very little is known about the mechanism of tumor control. By using NCI-H727 cells in an in vivo murine xenograft model of human NETs, we showed that 177Lu-DOTATATE PRRT led to increased infiltration of CD86+ antigen presenting cells into tumor tissue. We also found that following treatment with PRRT, there was significantly increased tumor infiltration by CD49b+/FasL+ NK cells potentially capable of tumor killing. Further investigation into the immunomodulatory effects of PRRT will be essential in improving treatment efficacy.

  11. Nociceptin/orphanin FQ peptide receptor agonist Ac-RYYRWKKKKKKK-NH2 (ZP120) induces antinatriuresis in rats by stimulation of amiloride-sensitive sodium reabsorption

    DEFF Research Database (Denmark)

    van Deurs, Ulla S K; Hadrup, Niels; Petersen, Jørgen Søberg

    2008-01-01

    The aim of the present study was to examine the mechanisms responsible for the antinatriuretic effect of the selective, peripherally acting, nociceptin/orphanin FQ peptide (NOP) receptor partial agonist Ac-RYYRWKKKKKKK-NH(2) (ZP120). Using immunohistochemistry, we showed that in the cortex NOP...... receptors are expressed in the distal convoluted tubules, the connecting tubules, and the collecting ducts. Using clearance techniques, we evaluated renal excretory function during acute administration of ZP120 (1 nmol/kg/min) in chronically catheterized, conscious rats (n = 8/group). To examine...... the hypothesis that ZP120 induces direct renal effects by modifying the activity of sodium transporters in the distal convoluted tubules or in the collecting ducts, ZP120-induced antinatriuresis was examined during coadministration of an inhibitor of the NaCl cotransporter, bendroflumethiazide, or a blocker...

  12. Induction of Anti-Tumor Immune Responses by Peptide Receptor Radionuclide Therapy with (177)Lu-DOTATATE in a Murine Model of a Human Neuroendocrine Tumor

    DEFF Research Database (Denmark)

    Wu, Yin; Pfeifer, Andreas Klaus; Myschetzky, Rebecca

    2013-01-01

    Peptide receptor radionuclide therapy (PRRT) is a relatively new mode of internally targeted radiotherapy currently in clinical trials. In PRRT, ionizing radioisotopes conjugated to somatostatin analogues are targeted to neuroendocrine tumors (NETs) via somatostatin receptors. Despite promising...... clinical results, very little is known about the mechanism of tumor control. By using NCI-H727 cells in an in vivo murine xenograft model of human NETs, we showed that 177Lu-DOTATATE PRRT led to increased infiltration of CD86+ antigen presenting cells into tumor tissue. We also found that following...... treatment with PRRT, there was significantly increased tumor infiltration by CD49b+/FasL+ NK cells potentially capable of tumor killing. Further investigation into the immunomodulatory effects of PRRT will be essential in improving treatment efficacy....

  13. Further characterization of the prototypical nociceptin/orphanin FQ peptide receptor agonist Ro 64-6198 in rodent models of conflict anxiety and despair.

    Science.gov (United States)

    Goeldner, Celia; Spooren, Will; Wichmann, Jürgen; Prinssen, Eric P

    2012-07-01

    Ro 64-6198, the prototypical non-peptide nociceptin/orphanin FQ peptide (NOP) receptor agonist, has potent anxiolytic-like effects in several preclinical models and species. However the effects of Ro 64-6198 on distinctive anxiety-provoking conditions related to unconditioned conflict behavior as well as its role in despair-like behavior remain to be addressed. Here we examined the effects of Ro 64-6198 on unconditioned conflict anxiety using stimuli with different salience and on regulation of autonomic reactivity and compared these to the effects of benzodiazepine receptor agonists. We also addressed the potential effects of Ro 64-6198 on despair-like behavior. Ro 64-6198 (0.1 to 10 mg/kg i.p.) and either diazepam or chlordiazepoxide were tested in the Vogel conflict punished drinking test (VCT) in Sprague Dawley rats, in the social approach-avoidance (SAA) test in Lewis rats, in the novelty-induced hypophagia (NIH) in C57BL/6J mice, and in stress-induced hyperthermia in NMRI mice, as well as in the forced swim test (FST) in Sprague Dawley rats and the tail suspension test (TST) in C57BL/6J mice. Ro 64-6198 (0.3 to 3 mg/kg) dose-dependently produced anxiolytic-like effects in the VCT, SAA, NIH, and SIH, similar to benzodiazepine receptor agonists. Ro 64-6198 did not alter immobility time in the FST and TST. Ro 64-6198 produced marked anxiolytic-like effects in response to a variety of mild to strong anxiogenic stimuli, whereas it did not facilitate depression-related behaviors. This data extend previous literature suggesting that NOP receptors are a viable target for the treatment of anxiety disorders.

  14. Modeling the interactions of a peptide-major histocompatibility class I ligand with its receptors. I. Recognition by two alpha beta T cell receptors

    DEFF Research Database (Denmark)

    Rognan, D; Stryhn, A; Fugger, L

    2000-01-01

    were successfully docked into the Ha255-262/Kk model. We have previously used a systematic and exhaustive panel of 144 single amino acid substituted analogs to analyze both MHC binding and T cell recognition of the parental viral peptide. This large body of experimental data was used to evaluate...... the models. They were found to account well for the experimentally obtained data, lending considerable support to the proposed models and suggesting a universal docking mode for alpha beta TCRs to MHC-peptide complexes. Such models may also be useful in guiding future rational experimentation....

  15. Physiological function of gastrin-releasing peptide and neuromedin B receptors in regulating itch scratching behavior in the spinal cord of mice.

    Directory of Open Access Journals (Sweden)

    Devki D Sukhtankar

    Full Text Available Pruritus (itch is a severe side effect associated with the use of drugs as well as hepatic and hematological disorders. Previous studies in rodents suggest that bombesin receptor subtypes i.e. receptors for gastrin-releasing peptide (GRPr and neuromedin B (NMBr differentially regulate itch scratching. However, to what degree spinal GRPr and NMBr regulate scratching evoked by intrathecally administered bombesin-related peptides is not known. The first aim of this study was to pharmacologically compare the dose-response curves for scratching induced by intrathecally administered bombesin-related peptides versus morphine, which is known to elicit itch in humans. The second aim was to determine if spinal GRPr and NMBr selectively or generally mediate scratching behavior. Mice received intrathecal injection of bombesin (0.01-0.3 nmol, GRP (0.01-0.3 nmol, NMB (0.1-1 nmol or morphine (0.3-3 nmol and were observed for one hour for scratching activity. Bombesin elicited most profound scratching over one hour followed by GRP and NMB, whereas morphine failed to evoke scratching response indicating the insensitivity of mouse models to intrathecal opioid-induced itch. Intrathecal pretreatment with GRPr antagonist RC-3095 (0.03-0.1 nmol produced a parallel rightward shift in the dose response curve of GRP-induced scratching but not NMB-induced scratching. Similarly, PD168368 (1-3 nmol only attenuated NMB but not GRP-induced scratching. Individual or co-administration of RC-3095 and PD168368 failed to alter bombesin-evoked scratching. A higher dose of RC-3095 (0.3 nmol generally suppressed scratching induced by all three peptides but also compromised motor function in the rotarod test. Together, these data indicate that spinal GRPr and NMBr independently drive itch neurotransmission in mice and may not mediate bombesin-induced scratching. GRPr antagonists at functionally receptor-selective doses only block spinal GRP-elicited scratching but the suppression of

  16. Lack of effect of the glucagon-like peptide-1 receptor agonist liraglutide on psoriasis in glucose-tolerant patients – a randomized placebo-controlled trial

    DEFF Research Database (Denmark)

    Faurschou, A; Gyldenløve, M; Rohde, U

    2015-01-01

    BACKGROUND: It has been proposed that glucagon-like peptide-1 receptor (GLP-1R) agonists used for the treatment of patients with type 2 diabetes might also improve their psoriasis. OBJECTIVE: To assess the efficacy and safety of the GLP-1R agonist liraglutide in glucose-tolerant patients with pla......BACKGROUND: It has been proposed that glucagon-like peptide-1 receptor (GLP-1R) agonists used for the treatment of patients with type 2 diabetes might also improve their psoriasis. OBJECTIVE: To assess the efficacy and safety of the GLP-1R agonist liraglutide in glucose-tolerant patients...... end points were improvement in PASI and dermatology life quality index (DLQI). Secondary end points included changes in weight and high sensitive C-reactive protein (hsCRP) levels, as well as adverse events. RESULTS: After 8 weeks of treatment, no significant change in PASI was found...... in the liraglutide group (mean±standard deviation: -2.6 ± 2.1) compared with the placebo group (-1.3 ± 2.4) (P = 0.228). No difference in DLQI was observed between the groups [-2.5 ± 4.4 (liraglutide) vs. -3.7 ± 4.8 (placebo); P = 0.564]. HsCRP did not change in any of the groups (0.26 ± 1 (placebo) vs. 0.25 ± 2...

  17. The Effect of RGD/NGR Peptide Modification of Melanoma Differentiation-Associated Gene-7/Interleukin-24 on Its Receptor Attachment, an In Silico Analysis.

    Science.gov (United States)

    Bina, Samaneh; Hosseini, Seyed Younes; Shenavar, Fatemeh; Hosseini, Ebrahim; Mortazavi, Mojtaba

    2017-08-01

    Melanoma differentiation-associated gene-7 (mda-7/interleukin [IL]-24), a unique tumor suppressor gene, induces selective apoptosis in tumor cells. Secreted IL-24 binds to heterodimeric receptor complexes of IL-20R1/IL-20R2, IL-22R1/IL-20R2, or sigma-1 receptor (Sig1R) that consequently enhances apoptosis. However, this mechanism is not well understood and most likely involves different pathways. Targeting of cytokine by tumor homing peptides (THPs) to the tumor cell surface molecule-like integrin shows to be beneficial in gene immunotherapy approaches. In this study, the in silico targeting of RGD/NGR-modified IL-24 to tumor cells was conducted. In this regard, the sequences of six new synthetic IL-24s that have been modified by RGD (Arg-Gly-Asp) or NGR (CRNGRGPDC) were aligned and their structures were modeled through homology modeling to evaluate their attachment potential to cognate receptor complexes such as IL-20R1/IL-20R2, IL-22R1/IL-20R2, or Sig1R. The results of homology modeling showed that modification of IL-24 with RGD motif in N-terminal and middle of this protein exhibited stronger interaction with cognate receptors. These results also demonstrated that modified IL-24 with RGD motif in the C-terminal has lost native activity. However, the interaction of THP-modified IL-24 with Sig1R would not be affected to that extent, interestingly. Conclusively, in silico analysis showed that modification of IL-24 with THPs needs a more detailed study as these modifications may disrupt native interaction with receptors and reduce apoptosis induction property. This structural analysis gives us a better understanding of mda-7/IL-24 interaction with cognate receptors and helps a more rational design for further cytokine modification.

  18. Cyclization of the urokinase receptor-derived ser-arg-ser-arg-tyr Peptide generates a potent inhibitor of trans-endothelial migration of monocytes.

    Directory of Open Access Journals (Sweden)

    Ali Munaim Yousif

    Full Text Available The receptor for the urokinase-type plasminogen activator (uPAR is a widely recognized master regulator of cell migration and uPAR88-92 is the minimal sequence required to induce cell motility. We and others have previously documented that the uPAR88-92 sequence, even in the form of synthetic linear peptide (SRSRY, interacts with the formyl peptide receptor type 1 (FPR1, henceforth inducing cell migration of several cell lines, including monocytes. FPR1 is mainly expressed by mammalian phagocytic leukocytes and plays a crucial role in chemotaxis. In this study, we present evidence that the cyclization of the SRSRY sequence generates a new potent and stable inhibitor of monocyte trafficking. In rat basophilic leukaemia RBL-2H3/ETFR cells expressing high levels of constitutively activated FPR1, the cyclic SRSRY peptide ([SRSRY] blocks FPR1 mediated cell migration by interfering with both internalization and ligand-uptake of FPR1. Similarly to RBL-2H3/ETFR cells, [SRSRY] competes with fMLF for binding to FPR1 and prevents agonist-induced FPR1 internalization in human monocyte THP-1 cells. Unlike scramble [RSSYR], [SRSRY] inhibits fMLF-directed migration of monocytes in a dose-dependent manner, with IC50 value of 0.01 nM. PMA-differentiated THP-1 cell exposure to fMLF gradient causes a marked cytoskeletal re-organization with the formation of F-actin rich pseudopodia that are prevented by the addition of [SRSRY]. Furthermore, [SRSRY] prevents migration of human primary monocytes and trans-endothelial migration of monocytes. Our findings indicate that [SRSRY] is a new FPR1 inhibitor which may suggest the development of new drugs for treating pathological conditions sustained by increased motility of monocytes, such as chronic inflammatory diseases.

  19. Comparison of the binding and internalization properties of 12 DOTA-coupled and {sup 111}In-labelled CCK2/gastrin receptor binding peptides: a collaborative project under COST Action BM0607

    Energy Technology Data Exchange (ETDEWEB)

    Aloj, Luigi; Aurilio, Michela; Rinaldi, Valentina; D' Ambrosio, Laura [Istituto Nazionale Tumori, Fondazione ' ' G. Pascale' ' , AF Medicina Nucleare, Naples (Italy); Tesauro, Diego [Universita ' ' Federico II' ' , CIRPeB, Naples (Italy); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Maina, Theodosia [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Mansi, Rosalba [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Guggenberg, Elisabeth von [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Joosten, Lieke [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Institute of Cancer, Barts and the London Queen Mary' s School of Medicine and Dentistry, Centre for Molecular Oncology and Imaging, London (United Kingdom); Breeman, W.A.P.; Blois, Erik de; Koelewijn, Stuart; Melis, Marleen; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Waser, Beatrice; Beetschen, Karin; Reubi, Jean Claude [University of Berne, Berne (Switzerland)

    2011-08-15

    Specific overexpression of cholecystokinin 2 (CCK2)/gastrin receptors has been demonstrated in several tumours of neuroendocrine origin. In some of these cancer types, such as medullary thyroid cancer (MTC), a sensitive diagnostic modality is still unavailable and therapeutic options for inoperable lesions are needed. Peptide receptor radionuclide therapy (PRRT) may be a viable therapeutic strategy in the management of these patients. Several CCK2R-targeted radiopharmaceuticals have been described in recent years. As part of the European Union COST Action BM0607 we studied the in vitro and in vivo characteristics of 12 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated CCK2R binding peptides. In the present study, we analysed binding and internalization characteristics. Stability, biodistribution and imaging studies have been performed in parallel by other centres involved in the project. Determination of IC{sub 50} values was performed using autoradiography, with DOTA-peptides displacing {sup 125}I-CCK from receptors on tissue sections from human tumours. Saturation binding and internalization experiments were performed using {sup 111}In-labelled peptides. The rat AR42J cell line and the human A431-CCK2R transfected cell line were utilized for in vitro experiments; dissociation constants (K{sub d}) and apparent number of binding sites (B{sub max}) were determined. Internalization was determined in receptor-expressing cells by incubating with tracer amounts of peptide at 37 and 4 C for different times up to 120 min. Surface-bound peptide was then stripped either by acid wash or subsequent incubation with 1 {mu}M unlabelled peptide at 4 C. All peptides showed high receptor affinity with IC{sub 50} values ranging from 0.2 to 3.4 nM. Saturation experiments also showed high affinity with K{sub d} values in the 10{sup -9}-10{sup -8} M range. B{sub max} values estimated in A431-CCK2R cells ranged from 0.6 to 2.2 x 10{sup 6} per cell. All peptides

  20. Peptide from Sea Anemone Metridium senile Affects Transient Receptor Potential Ankyrin-repeat 1 (TRPA1) Function and Produces Analgesic Effect.

    Science.gov (United States)

    Logashina, Yulia A; Mosharova, Irina V; Korolkova, Yulia V; Shelukhina, Irina V; Dyachenko, Igor A; Palikov, Victor A; Palikova, Yulia A; Murashev, Arkadii N; Kozlov, Sergey A; Stensvåg, Klara; Andreev, Yaroslav A

    2017-02-17

    The transient receptor potential ankyrin-repeat 1 (TRPA1) is an important player in pain and inflammatory pathways. It is a promising target for novel drug development for the treatment of a number of pathological states. A novel peptide producing a significant potentiating effect on allyl isothiocyanate- and diclofenac-induced currents of TRPA1 was isolated from the venom of sea anemone Metridium senile. It is a 35-amino acid peptide cross-linked by two disulfide bridges named τ-AnmTX Ms 9a-1 (short name Ms 9a-1) according to a structure similar to other sea anemone peptides belonging to structural group 9a. The structures of the two genes encoding the different precursor proteins of Ms 9a-1 were determined. Peptide Ms 9a-1 acted as a positive modulator of TRPA1 in vitro but did not cause pain or thermal hyperalgesia when injected into the hind paw of mice. Intravenous injection of Ms 9a-1 (0.3 mg/kg) produced a significant decrease in the nociceptive and inflammatory response to allyl isothiocyanate (the agonist of TRPA1) and reversed CFA (Complete Freund's Adjuvant)-induced inflammation and thermal hyperalgesia. Taken together these data support the hypothesis that Ms 9a-1 potentiates the response of TRPA1 to endogenous agonists followed by persistent functional loss of TRPA1-expressing neurons. We can conclude that TRPA1 potentiating may be useful as a therapeutic approach as Ms 9a-1 produces significant analgesic and anti-inflammatory effects in mice models of pain. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. In vitro and in vivo evaluation of 64Cu-labeled SarAr-bombesin analogs in gastrin-releasing peptide receptor-expressing prostate cancer.

    Science.gov (United States)

    Lears, Kimberly A; Ferdani, Riccardo; Liang, Kexian; Zheleznyak, Alexander; Andrews, Rebecca; Sherman, Christopher D; Achilefu, Samuel; Anderson, Carolyn J; Rogers, Buck E

    2011-03-01

    Bombesin is a 14-amino-acid amphibian peptide that binds with high affinity to the gastrin-releasing peptide receptor (GRPR), which is overexpressed on a variety of solid tumors. It has been demonstrated that bombesin analogs can be radiolabeled with a variety of radiometals for potential diagnosis and treatment of GRPR-positive tumors. In this regard, several studies have used different chelators conjugated to the 8 C-terminal amino acids of bombesin(7-14) for radiolabeling with (64)Cu. These analogs have demonstrated GRPR-specific small-animal PET of tumors but have various advantages and disadvantages. The objective of this study was to conjugate the previously described (1-N-(4-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]-eicosane-1,8-diamine) (SarAr) chelator to bombesin(7-14), radiolabel the conjugate with (64)Cu, and evaluate in vitro and in vivo. SarAr was synthesized as previously published and conjugated to bombesin(7-14) by solid-phase peptide synthesis using standard Fmoc chemistry. Succinic acid (SA), 8-aminooctanoic acid (Aoc), and Gly-Ser-Gly (GSG) were used as linkers between SarAr and bombesin(7-14) to yield the resulting SarAr-SA-Aoc-bombesin(7-14) and SarAr-SA-Aoc-GSG-bombesin(7-14) peptides. The unlabeled peptides were evaluated in a competitive binding assay using PC-3 prostate cancer cells and (125)I-Tyr(4)-bombesin to determine the inhibitory concentration of 50%. The peptides were radiolabeled with (64)Cu and evaluated for internalization into PC-3 cells in vitro and for in vivo tumor uptake in mice bearing PC-3 xenografts using biodistribution and small-animal PET/CT studies. The competitive binding assay demonstrated that both SarAr-SA-Aoc-bombesin(7-14) and SarAr-SA-Aoc-GSG-bombesin(7-14) bound with high affinity to GRPR with an inhibitory concentration of 50% of 3.5 and 4.5 nM, respectively. Both peptides were radiolabeled with (64)Cu at room temperature without further purification and demonstrated similar internalization into PC

  2. Does ligand-receptor mediated competitive effect or penetrating effect of iRGD peptide when co-administration with iRGD-modified SSL?

    Science.gov (United States)

    Zhang, Wei-Qiang; Yu, Ke-Fu; Zhong, Ting; Luo, Li-Min; Du, Ruo; Ren, Wei; Huang, Dan; Song, Ping; Li, Dan; Zhao, Yang; Wang, Chao; Zhang, Xuan

    2015-12-01

    Ligand-mediated targeting of anticancer therapeutic agents is a useful strategy for improving anti-tumor efficacy. It has been reported that co-administration of a tumor-penetrating peptide iRGD (CRGDK/RGPD/EC) enhances the efficacy of anticancer drugs. Here, we designed an experiment involving co-administration of iRGD-SSL-DOX with free iRGD to B16-F10 tumor bearing mice to examine the action of free iRGD. We also designed an experiment to investigate the location of iRGD-modified SSL when co-administered with free iRGD or free RGD to B16-F10 tumor bearing nude mice. Considering the sequence of iRGD, we selected the GPDC, RGD and CRGDK as targeting ligands to investigate the targeting effect of these peptides compared with iRGD on B16-F10 and MCF-7 cells, with or without enzymatic degradation. Finally, we selected free RGD, free CRGDK and free iRGD as ligand to investigate the inhibitory effect on RGD-, CRGDK- or iRGD-modified SSL on B16-F10 or MCF-7 cells. Our results indicated that iRGD targeting to tumor cells was ligand-receptor mediated involving RGD to αv-integrin receptor and CRGDK to NRP-1 receptor. Being competitive effect, the administration of free iRGD would not be able to further enhance the anti-tumor activity of iRGD-modified SSL. There is no need to co-administrate of free iRGD with the iRGD-modified nanoparticles for further therapeutic benefit.

  3. Imidazoline receptors in the heart: a novel target and a novel mechanism of action that involves atrial natriuretic peptides

    OpenAIRE

    S. Mukaddam-Daher; J. Gutkowska

    2004-01-01

    Chronic stimulation of sympathetic nervous activity contributes to the development and maintenance of hypertension, leading to left ventricular hypertrophy (LVH), arrhythmias and cardiac death. Moxonidine, an imidazoline antihypertensive compound that preferentially activates imidazoline receptors in brainstem rostroventrolateral medulla, suppresses sympathetic activation and reverses LVH. We have identified imidazoline receptors in the heart atria and ventricles, and shown that atrial I1-rec...

  4. Comparative biodistribution of 12 (1)(1)(1)In-labelled gastrin/CCK2 receptor-targeting peptides

    NARCIS (Netherlands)

    Laverman, P.; Joosten, L.; Eek, A.; Roosenburg, S.; Peitl, P.K.; Maina, T.; Macke, H.; Aloj, L.; Guggenberg, E. von; Sosabowski, J.K.; Jong, M. de; Reubi, J.C.; Oyen, W.J.G.; Boerman, O.C.

    2011-01-01

    PURPOSE: Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several

  5. Structural Analysis of the Dimerization Domain of the Human Estrogen Receptor and a Peptide Inhibitor of Dimerization

    Science.gov (United States)

    1998-08-01

    peptides as inactivators of multimeric enzymes: inhibitory and conformational properties of three fragments from Lactobacillus casei thymidylate ... synthase . Biochemistry 37, 6883-93. Renaud, J. P., Rochel, N., Ruff, M., Vivat, V., Chambon, P., Gronemeyer, H. & Moras, D. (1995) Crystal structure of the

  6. Improved pan-specific prediction of MHC class I peptide binding using a novel receptor clustering data partitioning strategy

    DEFF Research Database (Denmark)

    Mattsson, Andreas Holm; Kringelum, Jens Vindahl; Garde, C.

    2016-01-01

    Pan-specific prediction of receptor-ligand interaction is conventionally done using machine-learning methods that integrates information about both receptor and ligand primary sequences. To achieve optimal performance using machine learning, dealing with overfitting and data redundancy is critical...... strategy with the aim of altering this and construct data sets optimal for training of pan-specific receptor-ligand predictions focusing on receptor similarity rather than ligand similarity. We show that this receptor clustering method consistently in benchmarks covering affinity predictions, MHC ligand...... motifs, to others with no or very limited experimental characterization. The success of this approach has however proven to depend strongly on the similarity of the query molecule to the molecules with characterized specificity using in the machine-learning process. Here, we outline an alternative...

  7. Innovative Therapeutics: Designer Natriuretic Peptides.

    Science.gov (United States)

    Meems, Laura M G; Burnett, John C

    2016-12-01

    Endogenous natriuretic peptides serve as potent activators of particulate guanylyl cyclase receptors and the second messenger cGMP. Natriuretic peptides are essential in maintenance of volume homeostasis, and can be of myocardial, renal and endothelial origin. Advances in peptide engineering have permitted the ability to pursue highly innovative drug discovery strategies. This has resulted in designer natriuretic peptides that go beyond native peptides in efficacy, specificity, and resistance to enzymatic degradation. Together with recent improvements in peptide delivery systems, which have improved bioavailability, further advances in this field have been made. Therefore, designer natriuretic peptides with pleotropic actions together with strategies of chronic delivery have provided an unparalleled opportunity for the treatment of cardiovascular disease. In this review, we report the conceptual framework of peptide engineering of the natriuretic peptides that resulted in designer peptides for cardiovascular disease. We specifically provide an update on those currently in clinical trials for heart failure and hypertension, which include Cenderitide, ANX042 and ZD100.

  8. Glucagon-like peptide-1, but not glucose-dependent insulinotropic peptide, inhibits glucagon secretion via somatostatin (receptor subtype 2) in the perfused rat pancreas

    DEFF Research Database (Denmark)

    de Heer, J; Rasmussen, C; Coy, D H

    2008-01-01

    and somatostatin were studied in the presence of a high-affinity monoclonal somatostatin antibody and of a highly specific somatostatin receptor subtype 2 (SSTR2) antagonist (PRL-2903) in the isolated perfused rat pancreas. RESULTS: In control experiments, GLP-1 at 1 and 10 nmol/l reduced glucagon secretion...... than in control experiments (p antagonist completely abolished the GLP-1-induced suppression of glucagon secretion. In contrast, neither the GIP-induced stimulation of glucagon release nor its inhibition by 20 mmol/l glucose was altered by somatostatin antibody...... or SSTR2 antagonist administration. CONCLUSIONS/INTERPRETATION: We conclude that GLP-1 is capable of inhibiting glucagon secretion even in the absence of secretory products from the beta cell. It is highly likely that this is mediated via somatostatin interacting with SSTR2 on rat alpha cells. In contrast...

  9. Regulation of steroidogenesis by atrial natriuretic peptide (ANP) in the rat testis: differential involvement of GC-A and C receptors.

    Science.gov (United States)

    Pereira, Virgínia Mara; Costa, Amilton P Raposo; Rosa-E-Silva, Alzira Amelia Martins; Vieira, Maria Aparecida Ribeiro; Reis, Adelina Martha Dos

    2008-11-01

    Previous studies have established a stimulatory effect of natriuretic peptides (NP) on testosterone production in mouse Leydig cells as intense as that of LH. Chronic administration of ANP in mice, on the other side, reduced testosterone levels. So, the understanding of the role of ANP on testicular steroidogenesis has been impaired by discrepant findings. The aim of the present study was to clarify the physiological role of ANP in the rat testis steroidogenesis using a model that preserves the interactions between testis cells and a medium devoid of any circulating factors that could interfere with testosterone production. First, ANP was immunolocalized in the interstitial compartment of the rat testis, mainly in Leydig cells. We also determined the presence of ANP and both GC-A (guanylyl cyclase A) and C receptors by real-time PCR in testis. Perfusion in vitro of testis with ANP (1 and 3x10(-7)M) stimulated testosterone production in a time- and dose-dependent manner. On the other side, testosterone secretion induced by LH was blunted by ANP. Similar effect was obtained using the specific C receptor ligand, cANF, indicating the involvement of C receptor in such response. In conclusion, ANP stimulated testosterone production in the rat testis perfused in vitro but decreased testosterone production LH-induced, effect that seems to involve C receptor. To this extent, our results suggest the existence of a local and complex peptidergic system in the rat testis, involving ANP and its receptors that could importantly modulate the androgen biosynthesis.

  10. Adherence to NICE guidance on glucagon-like peptide-1 receptor agonists among patients with type 2 diabetes mellitus: an evaluation using the Clinical Practice Research Datalink.

    Science.gov (United States)

    Jameson, Kevin; D'Oca, Kalpana; Leigh, Paul; Murray-Thomas, Tarita

    2016-01-01

    To assess adherence to the UK's National Institute for Health and Care Excellence (NICE) guidelines for initiating and continuing glucagon-like peptide-1 (GLP-1) receptor agonists in patients with type 2 diabetes (T2DM). A retrospective cohort study of 7133 primary care patients ≥40 years with a first prescription for a GLP-1 receptor agonist following publication of NICE guideline/guidance. Patient characteristics and levels of clinical monitoring were assessed using descriptive analyses. Main outcomes were the proportion of patients initiating GLP-1 receptor agonists as part of NICE-recommended dual- or triple-therapy regimens; the proportions meeting NICE triple therapy initiation criteria (glycosylated hemoglobin [HbA1c] ≥7.5% and body mass index [BMI] ≥35 kg/m(2)) and the proportions continuing GLP-1 receptor agonist at 6 months according to NICE recommendations. Mean age at initiating GLP-1 receptor agonists was 58.2 years (SD 9.4), BMI 38.4 kg/m(2) (SD 6.8) and HbA1c 9.2% (SD 3.2%). Overall, only 25% of patients initiated GLP-1 receptor agonists as part of a NICE-recommended regimen. Of patients initiated on a recommended triple-therapy regimen, 50% (646/1284) fulfilled both NICE HbA1c and BMI initiation criteria. Approximately 18% (32/174) of patients continuing NICE-recommended dual therapy at 6 months achieved a 1% reduction in HbA1c and 6.4% (33/515) continuing with NICE-recommended triple therapy achieved NICE's target reductions for both HbA1c and body weight. About 8% of patients continuing exenatide as triple therapy (N = 243) achieved both targets. Adherence to NICE guidance for initiating and continuing GLP-1 receptor agonists is low. However, lack of data on ethnicity (for assessing NICE's BMI criteria) and on contraindications and/or hypersensitivity to other diabetes medication in the treatment pathway have limited our ability to fully assess adherence to GLP-1 prescribing. Further research is warranted to better understand general

  11. The PickPocket method for predicting binding specificities for receptors based on receptor pocket similarities: application to MHC-peptide binding

    DEFF Research Database (Denmark)

    Zhang, H.; Lund, Ole; Nielsen, M.

    2009-01-01

    exist, making determination of the binding specificity for each variant experimentally infeasible. Here, we present a method that can extrapolate from variants with known binding specificity to those where no experimental data are available. Results: For each position in the peptide ligand, we extracted...... of the specificities of MHC molecules in this library weighted by the similarity of their pocket-residues to the query. This PickPocket method is demonstrated to accurately predict MHC-peptide binding for a broad range of MHC alleles, including human and non-human species. In contrast to neural network-based pan......-specific methods, PickPocket was shown to be robust both when data is scarce and when the similarity to MHC molecules with characterized binding specificity is low. A consensus method combining the PickPocket and NetMHCpan methods was shown to achieve superior predictive performance. This study demonstrates how...

  12. Pancreatic neuroendocrine cell tumor secreting parathyroid hormone-related protein and gastrin: Report of a case.

    Science.gov (United States)

    Morita, Yoshifumi; Suzuki, Shohachi; Sakaguchi, Takanori; Oishi, Kosuke; Suzuki, Atsushi; Fukumoto, Kazuhiko; Inaba, Keisuke; Baba, Satoshi; Takehara, Yasuo; Konno, Hiroyuki

    2010-12-01

    This report presents a case of pancreatic neuroendocrine cell carcinoma with multiple liver metastases secreting gastrin and parathyroid hormone-related protein (PTHrP) related to lumbar bone fracture and hypercalcemia. A 58-year-old woman visited an affiliated hospital with a chief complaint of lumbago without any evidence of trauma. She was diagnosed with hepatic dysfunction and hypercalcemia as well as multiple lumbar compression fractures without osteolytic lesions. Abdominal computed tomography (CT) showed a hypervascular mass in the pancreatic tail and multiple liver tumors. Duodenal ulcers were found with gastrointestinal endoscopy. There was a marked increase in the serum gastrin level. She was diagnosed as gastrinoma with multiple liver metastases and was admitted to the hospital. She had an increase in serum PTHrP level without the elevation of intact parathyroid hormone at the time of admission. She underwent an extended right hepatectomy in addition to a distal pancreatectomy with a regional lymphadenectomy and splenectomy. The postoperative course was uneventful, and serum gastrin and PTHrP activities reduced to normal levels. She remained symptom-free, and serum calcium, gastrin, and PTHrP levels remain within the normal ranges 19 months after surgery without adjuvant therapy.

  13. Role of Parathyroid Hormone-Related Protein Signaling in Chronic Pancreatitis

    Energy Technology Data Exchange (ETDEWEB)

    Falzon, Miriam, E-mail: mfalzon@utmb.edu; Bhatia, Vandanajay [Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2015-06-18

    Chronic pancreatitis (CP), a progressive inflammatory disease where acini are destroyed and replaced by fibrous tissue, increases the risk for pancreatic cancer. Risk factors include alcohol, smoking, and obesity. The effects of these risk factors are exacerbated in patients with mutations in genes that predispose to CP. The different environmental and genetic factors produce the same clinical phenotype; once CP develops, disease course is the same regardless of etiology. Critical questions still need to be answered to understand what modifies predisposition to develop CP in persons exposed to risk factors. We postulate that risk factors modulate endogenous pathways, with parathyroid hormone-related protein (PTHrP) signaling being one such pathway. In support, PTHrP levels are elevated in mice treated with alcohol, and in mouse models of cerulein- and pancreatic duct ligation-induced CP. Disrupting the Pthrp gene in acinar cells exerts protective effects (decreased edema, histological damage, amylase and cytokine release, and fibrosis) in these CP models. PTHrP levels are elevated in human CP. Currently, CP care lacks specific pharmacological interventions. Targeting PTHrP signaling may present a novel therapeutic strategy that inhibits pancreatic inflammation and fibrosis, especially since the risk of developing pancreatic cancer is strongly associated with duration of chronic inflammation.

  14. Parathyroid Hormone-Related Protein Promotes Rat Stem Leydig Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Tiantian Song

    2017-11-01

    Full Text Available The regulatory factors for stem Leydig cell development are largely unknown. Herein, we reported that parathyroid hormone-related protein (PTHrP may be a factor to regulate this process. The effects of PTHrP on rat stem Leydig cell proliferation and differentiation were investigated using a stem Leydig cell culture system and an ethane dimethane sulfonate (EDS-treated in vivo Leydig cell regeneration model. PTHrP (1,000 pg/ml significantly increased medium testosterone level and up-regulated STAR, CYP17A1, and 17β-HSD3 expressions. Co-treatment with PKA inhibitor H-89 or PKC inhibitor U73122 reversed PTHrP-mediated increase of testosterone production in vitro. Intratesticular injection of PTHrP (100 ng/testis into the Leydig cell-depleted testis from post-EDS day 7 to 21 significantly increased serum testosterone level, up-regulated LHCGR, SCARB1, CYP11A1, 11β-HSD1, and CYP17A1 expressions. It also enlarged Leydig cell size without affecting PCNA-labeled Leydig cell number. This indicates that PTHrP promotes stem Leydig cell differentiation. PTHrP in vivo increased CREB and p-CREB levels, suggesting that PTHrP acts via a PKA-CREB signaling pathway. In conclusion, PTHrP stimulates stem Leydig cell differentiation without affecting its proliferation, showing its novel action and mechanism on rat stem Leydig cell development.

  15. Role of Parathyroid Hormone-Related Protein Signaling in Chronic Pancreatitis.

    Science.gov (United States)

    Falzon, Miriam; Bhatia, Vandanajay

    2015-06-18

    Chronic pancreatitis (CP), a progressive inflammatory disease where acini are destroyed and replaced by fibrous tissue, increases the risk for pancreatic cancer. Risk factors include alcohol, smoking, and obesity. The effects of these risk factors are exacerbated in patients with mutations in genes that predispose to CP. The different environmental and genetic factors produce the same clinical phenotype; once CP develops, disease course is the same regardless of etiology. Critical questions still need to be answered to understand what modifies predisposition to develop CP in persons exposed to risk factors. We postulate that risk factors modulate endogenous pathways, with parathyroid hormone-related protein (PTHrP) signaling being one such pathway. In support, PTHrP levels are elevated in mice treated with alcohol, and in mouse models of cerulein- and pancreatic duct ligation-induced CP. Disrupting the Pthrp gene in acinar cells exerts protective effects (decreased edema, histological damage, amylase and cytokine release, and fibrosis) in these CP models. PTHrP levels are elevated in human CP. Currently, CP care lacks specific pharmacological interventions. Targeting PTHrP signaling may present a novel therapeutic strategy that inhibits pancreatic inflammation and fibrosis, especially since the risk of developing pancreatic cancer is strongly associated with duration of chronic inflammation.

  16. Role of Parathyroid Hormone-Related Protein Signaling in Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Miriam Falzon

    2015-06-01

    Full Text Available Chronic pancreatitis (CP, a progressive inflammatory disease where acini are destroyed and replaced by fibrous tissue, increases the risk for pancreatic cancer. Risk factors include alcohol, smoking, and obesity. The effects of these risk factors are exacerbated in patients with mutations in genes that predispose to CP. The different environmental and genetic factors produce the same clinical phenotype; once CP develops, disease course is the same regardless of etiology. Critical questions still need to be answered to understand what modifies predisposition to develop CP in persons exposed to risk factors. We postulate that risk factors modulate endogenous pathways, with parathyroid hormone-related protein (PTHrP signaling being one such pathway. In support, PTHrP levels are elevated in mice treated with alcohol, and in mouse models of cerulein- and pancreatic duct ligation-induced CP. Disrupting the Pthrp gene in acinar cells exerts protective effects (decreased edema, histological damage, amylase and cytokine release, and fibrosis in these CP models. PTHrP levels are elevated in human CP. Currently, CP care lacks specific pharmacological interventions. Targeting PTHrP signaling may present a novel therapeutic strategy that inhibits pancreatic inflammation and fibrosis, especially since the risk of developing pancreatic cancer is strongly associated with duration of chronic inflammation.

  17. Pharmacology of AMG 416 (Velcalcetide), a novel peptide agonist of the calcium-sensing receptor, for the treatment of secondary hyperparathyroidism in hemodialysis patients.

    Science.gov (United States)

    Walter, Sarah; Baruch, Amos; Dong, Jin; Tomlinson, James E; Alexander, Shawn T; Janes, Julie; Hunter, Tom; Yin, Qun; Maclean, Derek; Bell, Gregory; Mendel, Dirk B; Johnson, Randolph M; Karim, Felix

    2013-08-01

    A novel peptide, AMG 416 (formerly KAI-4169, and with a United States Adopted Name: velcalcetide), has been identified that acts as an agonist of the calcium-sensing receptor (CaSR). This article summarizes the in vitro and in vivo characterization of AMG 416 activity and the potential clinical utility of this novel compound. AMG 416 activates the human CaSR in vitro, acting by a mechanism distinct from that of cinacalcet, the only approved calcimimetic, since it can activate the CaSR both in the presence or the absence of physiologic levels of extracellular calcium. Administration of AMG 416 in vivo into either normal or renally compromised rats results in dose-dependent reductions in parathyroid hormone (PTH) levels and corresponding decreases in serum calcium, regardless of the baseline level of PTH. Treatment of 5/6 nephrectomized rats with AMG 416 resulted in dramatic improvements in their metabolic profile, including lower PTH and serum creatinine levels, reduced amounts of vascular calcification, attenuated parathyroid hyperplasia, and greater expression of the parathyroid gland regulators CaSR, vitamin D receptor, and FGF23 receptor compared with vehicle-treated animals. No drug accumulation was observed under this dosing regimen, and the terminal half-life of AMG 416 was estimated to be 2-4.5 hours. As a long-acting CaSR agonist, AMG 416 is an innovative new therapy for the treatment of hemodialysis patients with secondary hyperparathyroidism.

  18. Improved pan-specific prediction of MHC class I peptide binding using a novel receptor clustering data partitioning strategy.

    Science.gov (United States)

    Mattsson, A H; Kringelum, J V; Garde, C; Nielsen, M

    2016-12-01

    Pan-specific prediction of receptor-ligand interaction is conventionally done using machine-learning methods that integrates information about both receptor and ligand primary sequences. To achieve optimal performance using machine learning, dealing with overfitting and data redundancy is critical. Most often so-called ligand clustering methods have been used to deal with these issues in the context of pan-specific receptor-ligand predictions, and the MHC system the approach has proven highly effective for extrapolating information from a limited set of receptors with well characterized binding motifs, to others with no or very limited experimental characterization. The success of this approach has however proven to depend strongly on the similarity of the query molecule to the molecules with characterized specificity using in the machine-learning process. Here, we outline an alternative strategy with the aim of altering this and construct data sets optimal for training of pan-specific receptor-ligand predictions focusing on receptor similarity rather than ligand similarity. We show that this receptor clustering method consistently in benchmarks covering affinity predictions, MHC ligand and MHC epitope identification perform better than the conventional ligand clustering method on the alleles with remote similarity to the training set. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Parathyroid hormone-related protein and calcium regulation in vitamin D-deficient sea bream (Sparus auratus).

    NARCIS (Netherlands)

    Abbink, W.; Hang, X.M.; Guerreiro, P.M.; Spanings, F.A.T.; Ross, H.A.; Canario, A.V.; Flik, G.

    2007-01-01

    Gilthead sea bream (Sparus auratus L.) were fed a vitamin D-deficient diet for 22 weeks. Growth rate, whole body mineral pools and calcium balance were determined. Plasma parathyroid hormone-related protein (PTHrP) and calcitriol levels were assessed. Expression of mRNA for pthrp and pth1r was

  20. Assessment of Multifactor Gene-Environment Interactions and Ovarian Cancer Risk: Candidate Genes, Obesity, and Hormone-Related Risk Factors

    NARCIS (Netherlands)

    Usset, J.L.; Raghavan, R.; Tyrer, J.P.; McGuire, V.; Sieh, W.; Webb, P.; Chang-Claude, J.; Rudolph, A.; Anton-Culver, H.; Berchuck, A.; Brinton, L.; Cunningham, J.M.; Defazio, A.; Doherty, J.A.; Edwards, R.P.; Gayther, S.A.; Gentry-Maharaj, A.; Goodman, M.T.; Hogdall, E.; Jensen, A.; Johnatty, S.E.; Kiemeney, L.A.L.M.; Kjaer, S.K.; Larson, M.C.; Lurie, G.; Massuger, L.F.; Menon, U.; Modugno, F.; Moysich, K.B.; Ness, R.B.; Pike, M.C.; Ramus, S.J.; Rossing, M.A.; Rothstein, J.; Song, H.; Thompson, P.J.; Berg, D.J. Van Den; Vierkant, R.A.; Wang-Gohrke, S.; Wentzensen, N.; Whittemore, A.S.; Wilkens, L.R.; Wu, A.H.; Yang, H.; Pearce, C.L.; Schildkraut, J.M.; Pharoah, P.; Goode, E.L.; Fridley, B.L.

    2016-01-01

    BACKGROUND: Many epithelial ovarian cancer (EOC) risk factors relate to hormone exposure and elevated estrogen levels are associated with obesity in postmenopausal women. Therefore, we hypothesized that gene-environment interactions related to hormone-related risk factors could differ between obese

  1. Efficacy and safety of prolonged-release lanreotide in patients with gastrointestinal neuroendocrine tumors and hormone-related symptoms

    NARCIS (Netherlands)

    Wymenga, ANM; Eriksson, B; Salmela, PI; Jacobsen, MB; Van Cutsem, EJDG; Fiasse, RH; Valimaki, MJ; Renstrup, J; de Vries, EGE; Oberg, KE

    Purpose: To evaluate the prolonged release (PR) of the long-acting somatostatin analog lanreotide in patients with gastrointestinal neuroendocrine tumors and its effect on hormone-related symptomatology, tumor markers, tumor size, tolerability, and quality of life (QOL), Patients and Methods:

  2. Hypogonadotropic Hypogonadism Due to Loss of Function of the KiSS1-Derived Peptide Receptor GPR54

    National Research Council Canada - National Science Library

    Nicolas de Roux; Emmanuelle Genin; Jean-Claude Carel; Fumihiko Matsuda; Jean-Louis Chaussain; Edwin Milgrom

    2003-01-01

    ...), hypogonadotropic hypogonadism is referred to as isolated hypogonadotropic hypogonadism (IHH). A limited number of IHH cases are due to loss-of-function mutations of the gonadotropin-releasing hormone receptor...

  3. The glucagon-like peptide 1 (GLP-1) receptor agonist exendin-4 reduces cocaine self-administration in mice

    DEFF Research Database (Denmark)

    Sorensen, Gunnar; Reddy, India A.; Weikop, Pia

    2015-01-01

    tegmental area (VTA) and the nucleus accumbens (NAc). Dopaminergic neurons in the VTA project to the NAc, and these neurons play a pivotal role in the rewarding effects of drugs of abuse. Based on the anatomical distribution of GLP-1 receptors in the brain and the well-established effects of GLP-1 on food...... implicating central GLP-1 receptors in these responses. The present results demonstrate that the GLP-1 system modulates cocaine's effects on behavior and dopamine homeostasis, indicating that the GLP-1 receptor may be a novel target for the pharmacological treatment of drug addiction....... reward, we decided to investigate the effect of the GLP-1 analogue exendin-4 on cocaine- and dopamine D1-receptor agonist-induced hyperlocomotion, on acute and chronic cocaine self-administration, on cocaine-induced striatal dopamine release in mice and on cocaine-induced c-fos activation. Here, we...

  4. Lupin peptides lower low-density lipoprotein (LDL) cholesterol through an up-regulation of the LDL receptor/sterol regulatory element binding protein 2 (SREBP2) pathway at HepG2 cell line.

    Science.gov (United States)

    Lammi, Carmen; Zanoni, Chiara; Scigliuolo, Graziana M; D'Amato, Alfonsina; Arnoldi, Anna

    2014-07-23

    Previous experiments in suitable animal models and in mild hypercholesterolemic individuals have shown that the consumption of lupin proteins may be useful for controlling total and low-density lipoprotein (LDL) cholesterol levels. With the objective of providing evidence that peptides deriving from the hydrolysis of lupin proteins may be responsible of the observed activities and for investigating the mechanism of action, HepG2 cells were treated with lupin peptides obtained by either pepsin (P) or trypsin (T) hydrolysis, and molecular and functional investigations were performed on the LDL receptor/SREBP2 pathway. For the first time, this paper provides experimental evidence that lupin peptides are able to interfere with the HMGCoAR activity, up-regulating the LDL receptor (136 and 84% vs the control for P and T peptides, respectively, at 1 mg/mL) and SREBP2 proteins (148 and 73% vs the control for P and T peptides, respectively, at 1 mg/mL) via the activation of PI3K/Akt/GSK3β pathways and increasing the LDL uptake at HepG2 cell line (40 and 50% vs the control for P and T peptides, respectively, at 1 mg/mL). These results may be useful in explaining the activities observed in vivo in animals and humans treated with lupin protein.

  5. mRNA expression of 5-hydroxytryptamine 1B, 1D, and 1F receptors and their role in controlling the release of calcitonin gene-related peptide in the rat trigeminovascular system

    DEFF Research Database (Denmark)

    Amrutkar, Dipak V; Ploug, Kenneth B; Hay-Schmidt, Anders

    2012-01-01

    Triptans, a family of 5-hydroxytryptamine (5-HT) 1B, 1D, and 1F receptor agonists, are used in the acute treatment of migraine attacks. The site of action and subtypes of the 5-HT(1) receptor that mediate the antimigraine effect have still to be identified. This study investigated the m......RNA expression of these receptors and the role of 5-HT(1) receptor subtypes in controlling the release of calcitonin gene-related peptide (CGRP) in rat dura mater, trigeminal ganglion (TG), and trigeminal nucleus caudalis (TNC). The mRNA for each receptor subtype was quantified by quantitative real......-time polymerase chain reaction. A high potassium concentration was used to release CGRP from dura mater, isolated TG, and TNC in vitro. The immunoreactive CGRP (iCGRP) release was measured by enzyme-linked immunoassay. The mRNA transcripts of the 3 5-HT(1) receptor subtypes were detected in the trigeminovascular...

  6. [Dulaglutide (Trulicity®), a new once-weekly agonist of glucagon-like peptide-1 receptors for type 2 diabetes].

    Science.gov (United States)

    Scheen, A J

    2016-03-01

    Dulaglutide (Trulicity®) is a new once-weekly agonist of Glucagon-Like Peptide-1 (GLP-1) receptors indicated in the treatment of type 2 diabetes. Phase III clinical trials in AWARD programme demonstrated the efficacy and safety of dulaglutide in patients with type 2 diabetes treated by diet and exercise, metformin, a combination of metformin and a sulfonylurea or metformin and pioglitazone or even by supplements of prandial insulin. In the AWARD programme, dulaglutide (subcutaneous 0.75 or 1.5 mg once weekly) exerted a greater glucose-lowering activity than metformin, sitagliptin, exenatide or insulin glargine, and was non-inferior to liraglutide 1.8 mg once daily. Dulaglutide is currently reimbursed in Belgium after failure of and in combination with a dual oral therapy with metformin and a sulfonylurea or metformin and pioglitazone.

  7. The fibroblast growth factor receptor (FGFR) agonist FGF1 and the neural cell adhesion molecule-derived peptide FGL activate FGFR substrate 2alpha differently

    DEFF Research Database (Denmark)

    Chen, Yongshuo; Li, Shizhong; Berezin, Vladimir

    2010-01-01

    Activation of fibroblast growth factor (FGF) receptors (FGFRs) both by FGFs and by the neural cell adhesion molecule (NCAM) is crucial in the development and function of the nervous system. We found that FGFR substrate 2alpha (FRS2alpha), Src homologous and collagen A (ShcA), and phospholipase......-Cgamma (PLCgamma) were all required for neurite outgrowth from cerebellar granule neurons (CGNs) induced by FGF1 and FGL (an NCAM-derived peptide agonist of FGFR1). Like FGF1, FGL induced tyrosine phosphorylation of FGFR1, FRS2alpha, ShcA, and PLCgamma in a time- and dose-dependent manner. However, the activation...... of FRS2alpha by FGL was significantly lower than the activation by FGF1, indicating a differential signaling profile induced by NCAM compared with the cognate growth factor....

  8. Nitric oxide synthase, calcitonin gene-related peptide and NK-1 receptor mechanisms are involved in GTN-induced neuronal activation

    DEFF Research Database (Denmark)

    Ramachandran, Roshni; Bhatt, Deepak Kumar; Ploug, Kenneth Beri

    2014-01-01

    BACKGROUND AND AIM: Infusion of glyceryltrinitrate (GTN), a nitric oxide (NO) donor, in awake, freely moving rats closely mimics a universally accepted human model of migraine and responds to sumatriptan treatment. Here we analyse the effect of nitric oxide synthase (NOS) and calcitonin gene......-related peptide (CGRP) systems on the GTN-induced neuronal activation in this model. MATERIALS AND METHODS: The femoral vein was catheterised in rats and GTN was infused (4 µg/kg/min, for 20 minutes, intravenously). Immunohistochemistry was performed to analyse Fos, nNOS and CGRP and Western blot for measuring n......NOS protein expression. The effect of olcegepant, L-nitro-arginine methyl ester (L-NAME) and neurokinin (NK)-1 receptor antagonist L-733060 were analysed on Fos activation. RESULTS: GTN-treated rats showed a significant increase of nNOS and CGRP in dura mater and CGRP in the trigeminal nucleus caudalis (TNC...

  9. Glucagon-like peptide 1 receptor activation regulates cocaine actions and dopamine homeostasis in the lateral septum by decreasing arachidonic acid levels

    DEFF Research Database (Denmark)

    Reddy, I A; Pino, J A; Weikop, P

    2016-01-01

    Agonism of the glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) has been effective at treating aspects of addictive behavior for a number of abused substances, including cocaine. However, the molecular mechanisms and brain circuits underlying the therapeutic effects of GLP-1R signaling on cocaine...... actions remain elusive. Recent evidence has revealed that endogenous signaling at the GLP-1R within the forebrain lateral septum (LS) acts to reduce cocaine-induced locomotion and cocaine conditioned place preference, both considered dopamine (DA)-associated behaviors. DA terminals project from...... the ventral tegmental area to the LS and express the DA transporter (DAT). Cocaine acts by altering DA bioavailability by targeting the DAT. Therefore, GLP-1R signaling might exert effects on DAT to account for its regulation of cocaine-induced behaviors. We show that the GLP-1R is highly expressed within...

  10. Near-normalization of glycaemic control with glucagon-like peptide-1 receptor agonist treatment combined with exercise in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Mensberg, Pernille; Nyby, Signe; Jørgensen, Peter Godsk

    2017-01-01

    AIMS: Exercise as well as glucagon-like peptide-1 receptor agonist (GLP-1RA) treatment improves glycaemic control in patients with type 2 diabetes. We investigated the effects of exercise in combination with a GLP-1RA (liraglutide) or placebo for the treatment of type 2 diabetes. METHODS: Thirty......-three overweight, dysregulated and sedentary patients with type 2 diabetes were randomly allocated to 16 weeks of exercise and liraglutide or exercise and placebo. Both groups had three supervised 60-minute training sessions per week including spinning and resistance training. RESULTS: HbA1c levels dropped by 2...... the intervention. CONCLUSIONS: In obese patients with type 2 diabetes, exercise combined with GLP-1RA treatment near-normalised HbA1c levels and caused a robust weight loss when compared to placebo. These results suggest that a combination of exercise and GLP-1RA treatment is effective in type 2 diabetes....

  11. Short-acting glucagon-like peptide-1 receptor agonists as add-on to insulin therapy in type 1 diabetes

    DEFF Research Database (Denmark)

    Albèr, Anders; Brønden, Andreas; Knop, Filip K

    2017-01-01

    , which is associated with well-described and unfortunate adverse effects such as hypoglycaemia and increased body weight. Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are the focus of increasing interest as a possible adjunctive treatment to insulin in type 1 diabetes because......A large proportion of patients with type 1 diabetes do not reach their glycaemic target of glycated hemoglobin (HbA1c) diabetes are overweight and obese. Treatment of type 1 diabetes is based on insulin therapy...... of their glucagonostatic and extrapancreatic effects. So far, the focus has mainly been on the long-acting GLP-1RAs, but the risk-benefit ratio emerging from studies evaluating the effect of long-acting GLP-1RAs as adjunctive therapy to insulin therapy in patients with type 1 diabetes has been disappointing. This might...

  12. In Vivo Stabilization of a Gastrin-Releasing Peptide Receptor Antagonist Enhances PET Imaging and Radionuclide Therapy of Prostate Cancer in Preclinical Studies.

    Science.gov (United States)

    Chatalic, Kristell L S; Konijnenberg, Mark; Nonnekens, Julie; de Blois, Erik; Hoeben, Sander; de Ridder, Corrina; Brunel, Luc; Fehrentz, Jean-Alain; Martinez, Jean; van Gent, Dik C; Nock, Berthold A; Maina, Theodosia; van Weerden, Wytske M; de Jong, Marion

    2016-01-01

    A single tool for early detection, accurate staging, and personalized treatment of prostate cancer (PCa) would be a major breakthrough in the field of PCa. Gastrin-releasing peptide receptor (GRPR) targeting peptides are promising probes for a theranostic approach for PCa overexpressing GRPR. However, the successful application of small peptides in a theranostic approach is often hampered by their fast in vivo degradation by proteolytic enzymes, such as neutral endopeptidase (NEP). Here we show for the first time that co-injection of a NEP inhibitor (phosphoramidon (PA)) can lead to an impressive enhancement of diagnostic sensitivity and therapeutic efficacy of the theranostic (68)Ga-/(177)Lu-JMV4168 GRPR-antagonist. Co-injection of PA (300 µg) led to stabilization of (177)Lu-JMV4168 in murine peripheral blood. In PC-3 tumor-bearing mice, PA co-injection led to a two-fold increase in tumor uptake of (68)Ga-/(177)Lu-JMV4168, 1 h after injection. In positron emission tomography (PET) imaging with (68)Ga-JMV4168, PA co-injection substantially enhanced PC-3 tumor signal intensity. Radionuclide therapy with (177)Lu-JMV4168 resulted in significant regression of PC-3 tumor size. Radionuclide therapy efficacy was confirmed by production of DNA double strand breaks, decreased cell proliferation and increased apoptosis. Increased survival rates were observed in mice treated with (177)Lu-JMV4168 plus PA as compared to those without PA. This data shows that co-injection of the enzyme inhibitor PA greatly enhances the theranostic potential of GRPR-radioantagonists for future application in PCa patients.

  13. Alanine Mutagenesis in the Complementarity Determining Region 3 of the MTB and HIV-1 Peptide-Bispecific T Cell Receptor Beta Chain Affects Ligand Recognition.

    Science.gov (United States)

    Zhou, Chao-Ying; Wang, Rui-Ning; Wen, Qian; He, Wen-Ting; Zhang, Shi-Meng; Du, Xia-Lin; Yang, Jia-Hui; Ma, Li

    2017-01-01

    Mycobacterium tuberculosis /human immunodeficiency virus (MTB/HIV) coinfection presents a special challenge to the prevention and treatment of tuberculosis and HIV/AIDS. Adoptive transfer of high-affinity T cell receptor (TCR) gene-modified T cells against MTB and HIV antigens is a promising approach to treating MTB/HIV coinfected patients whose cellular immunity is obviously disordered. We have previously successfully identified that a bispecific TCR screened out from peripheral blood mononuclear cells of a HLA-A*0201 + healthy individual using the complementarity determining region 3 (CDR3) spectratype analysis recognizes both MTB Ag85B 199-207 and HIV-1 Env 120-128 peptide. However, it has not been known how residues on CDR3 loops, which have been shown to play a leading role in antigen binding and specificity contribute to the bispecific TCR contact with the peptide-major histocompatibility complex (MHC) complexes. In this study, we provided an extensive investigation of residues in the predicted CDR3 of the bispecific TCR beta (β) chain using alanine scanning mutagenesis. Our data showed that three of the five substituted residues (G115A, T116A, A117G) in CDR3β of the bispecific TCR caused a significantly diminished T cell response to antigen, whereas the remaining two substituted residues (D114A, S118A) resulted in completely eliminated response, thus identifying the two residues that were particularly critical for the recognition of peptide-MHC in the bispecific TCR. These findings will provide an imperative foundation for generating an improved high-affinity bispecific TCR for use in T cell adoptive immunotherapy for MTB/HIV coinfected individuals.

  14. Gastrin-releasing peptide receptor-based targeting using bombesin analogues is superior to metabolism-based targeting using choline for in vivo imaging of human prostate cancer xenografts

    NARCIS (Netherlands)

    R.P.J. Schroeder (Rogier); W.M. van Weerden (Wytske); E.P. Krenning (Eric); C.H. Bangma (Chris); S.C. Berndsen (Saskia); C.H. Grievink-De Ligt; H.C. Groen (Harald); S. Reneman (Suzanne); E. de Blois (Erik); W.A.P. Breeman (Wouter); M. de Jong (Marcel)

    2011-01-01

    textabstractPurpose: Prostate cancer (PC) is a major health problem. Overexpression of the gastrin-releasing peptide receptor (GRPR) in PC, but not in the hyperplastic prostate, provides a promising target for staging and monitoring of PC. Based on the assumption that cancer cells have increased

  15. In vitro Evaluation of a Bombesin Antagonistic Analogue Conjugated with DOTA-Ala(SO{sub 3}H)-Aminooctanoyl for Targeting of the Gastrin-releasing Peptide Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae Cheong; Cho, Eun Ha; Kim, Jin Joo; Lee, So Young; Choi, Sang Mu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    As Bombesin (BBS) binds with high affinity to GRPR, BBS derivatives have been labeled with various radionuclides such as {sup 99}mTc, {sup 111}In, {sup 90}Y, {sup 64}Cu, {sup 177}Lu, {sup 68}Ga, or {sup 18}F and have proved to be successful candidates for peptide receptor radiotherapy (PRRT). In this study, we employed Ala(SO{sub 3}H)-Aminooctanoyl as a linker of BBS antagonistic peptide sequence, Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH{sub 2}, with DOTA to prepare radiolabeled candidates for GRPR targeting. A DOTA-conjugated BBS antagonistic analogue was synthesized and radiolabeled with {sup 177}Lu, and in vitro characteristics on GRPR-overexpressing human prostate tumor cells were evaluated. In conclusion, a novel BBS antagonistic analogue, {sup 177}Lu-DOTA-sBBNA, is a promising candidate for the targeting of GRPR-over-expressing tumors. Further investigations to evaluate its in vivo characteristics and therapeutic efficacy are needed.

  16. Enteric commensal bacteria induce extracellular signal-regulated kinase pathway signaling via formyl peptide receptor-dependent redox modulation of dual specific phosphatase 3.

    Science.gov (United States)

    Wentworth, Christy C; Alam, Ashfaqul; Jones, Rheinallt M; Nusrat, Asma; Neish, Andrew S

    2011-11-04

    The normal microbial occupants of the mammalian intestine are crucial for maintaining gut homeostasis, yet the mechanisms by which intestinal cells perceive and respond to the microbiota are largely unknown. Intestinal epithelial contact with commensal bacteria and/or their products has been shown to activate noninflammatory signaling pathways, such as extracellular signal-related kinase (ERK), thus influencing homeostatic processes. We previously demonstrated that commensal bacteria stimulate ERK pathway activity via interaction with formyl peptide receptors (FPRs). In the current study, we expand on these findings and show that commensal bacteria initiate ERK signaling through rapid FPR-dependent reactive oxygen species (ROS) generation and subsequent modulation of MAP kinase phosphatase redox status. ROS generation induced by the commensal bacteria Lactobacillus rhamnosus GG and the FPR peptide ligand, N-formyl-Met-Leu-Phe, was abolished in the presence of selective inhibitors for G protein-coupled signaling and FPR ligand interaction. In addition, pretreatment of cells with inhibitors of ROS generation attenuated commensal bacteria-induced ERK signaling, indicating that ROS generation is required for ERK pathway activation. Bacterial colonization also led to oxidative inactivation of the redox-sensitive and ERK-specific phosphatase, DUSP3/VHR, and consequent stimulation of ERK pathway signaling. Together, these data demonstrate that commensal bacteria and their products activate ROS signaling in an FPR-dependent manner and define a mechanism by which cellular ROS influences the ERK pathway through a redox-sensitive regulatory circuit.

  17. CSA13 inhibits colitis-associated intestinal fibrosis via a formyl peptide receptor like-1 mediated HMG-CoA reductase pathway.

    Science.gov (United States)

    Xu, Chunlan; Ghali, Sally; Wang, Jiani; Shih, David Q; Ortiz, Christina; Mussatto, Caroline C; Lee, Elaine C; Tran, Diana H; Jacobs, Jonathan P; Lagishetty, Venu; Fleshner, Phillip; Robbins, Lori; Vu, Michelle; Hing, Tressia C; McGovern, Dermot P B; Koon, Hon Wai

    2017-11-27

    Many Crohn's disease (CD) patients develop intestinal strictures, which are difficult to prevent and treat. Cationic steroid antimicrobial 13 (CSA13) shares cationic nature and antimicrobial function with antimicrobial peptide cathelicidin. As many functions of cathelicidin are mediated through formyl peptide receptor-like 1 (FPRL1), we hypothesize that CSA13 mediates anti-fibrogenic effects via FPRL1. Human intestinal biopsies were used in clinical data analysis. Chronic trinitrobenzene sulfonic acid (TNBS) colitis-associated intestinal fibrosis mouse model with the administration of CSA13 was used. Colonic FPRL1 mRNA expression was positively correlated with the histology scores of inflammatory bowel disease patients. In CD patients, colonic FPRL1 mRNA was positively correlated with intestinal stricture. CSA13 administration ameliorated intestinal fibrosis without influencing intestinal microbiota. Inhibition of FPRL1, but not suppression of intestinal microbiota, reversed these protective effects of CSA13. Metabolomic analysis indicated increased fecal mevalonate levels in the TNBS-treated mice, which were reduced by the CSA13 administration. CSA13 inhibited colonic HMG-CoA reductase activity in an FPRL1-dependent manner. Mevalonate reversed the anti-fibrogenic effect of CSA13. The increased colonic FPRL1 expression is associated with severe mucosal disease activity and intestinal stricture. CSA13 inhibits intestinal fibrosis via FPRL1-dependent modulation of HMG-CoA reductase pathway.

  18. Dual activation of pathways regulated b