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Biniari G, Markatos C, Nteli A, Tzoupis H, Simal C, Vlamis-Gardikas A, Karageorgos V, Pirmettis I, Petrou P, Venihaki M, Liapakis G, Tselios T. Rational Design, Synthesis and Binding Affinity Studies of Anthraquinone Derivatives Conjugated to Gonadotropin-Releasing Hormone (GnRH) Analogues towards Selective Immunosuppression of Hormone-Dependent Cancer. Int J Mol Sci 2023; 24:15232. [PMID: 37894912 PMCID: PMC10607160 DOI: 10.3390/ijms242015232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/06/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is pivotal in regulating human reproduction and fertility through its specific receptors. Among these, gonadotropin-releasing hormone receptor type I (GnRHR I), which is a member of the G-protein-coupled receptor family, is expressed on the surface of both healthy and malignant cells. Its presence in cancer cells has positioned this receptor as a primary target for the development of novel anti-cancer agents. Moreover, the extensive regulatory functions of GnRH have underscored decapeptide as a prominent vehicle for targeted drug delivery, which is accomplished through the design of appropriate conjugates. On this basis, a rationally designed series of anthraquinone/mitoxantrone-GnRH conjugates (con1-con8) has been synthesized herein. Their in vitro binding affinities range from 0.06 to 3.42 nM, with six of them (con2-con7) demonstrating higher affinities for GnRH than the established drug leuprolide (0.64 nM). Among the mitoxantrone based GnRH conjugates, con3 and con7 show the highest affinities at 0.07 and 0.06 nM, respectively, while the disulfide bond present in the conjugates is found to be readily reduced by the thioredoxin (Trx) system. These findings are promising for further pharmacological evaluation of the synthesized conjugates with the prospect of performing future clinical studies.
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Affiliation(s)
- Georgia Biniari
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
| | - Christos Markatos
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece; (C.M.); (V.K.)
| | - Agathi Nteli
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
| | - Haralambos Tzoupis
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
| | - Carmen Simal
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
| | - Alexios Vlamis-Gardikas
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
| | - Vlasios Karageorgos
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece; (C.M.); (V.K.)
| | - Ioannis Pirmettis
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research “Demokritos”, 15341 Athens, Greece; (I.P.); (P.P.)
| | - Panagiota Petrou
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research “Demokritos”, 15341 Athens, Greece; (I.P.); (P.P.)
| | - Maria Venihaki
- Department of Clinical Chemistry, School of Medicine, University of Crete, 71003 Heraklion, Greece;
| | - George Liapakis
- Department of Pharmacology, School of Medicine, University of Crete, 71003 Heraklion, Greece; (C.M.); (V.K.)
| | - Theodore Tselios
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (G.B.); (A.N.); (H.T.); (C.S.); (A.V.-G.)
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Uzonwanne VO, Navabi A, Obayemi JD, Hu J, Salifu AA, Ghahremani S, Ndahiro N, Rahbar N, Soboyejo W. Triptorelin-functionalized PEG-coated biosynthesized gold nanoparticles: Effects of receptor-ligand interactions on adhesion to triple negative breast cancer cells. BIOMATERIALS ADVANCES 2022; 136:212801. [PMID: 35929297 DOI: 10.1016/j.bioadv.2022.212801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/26/2022] [Accepted: 04/09/2022] [Indexed: 11/29/2022]
Abstract
This paper presents the results of an experimental and computational study of the adhesion of triptorelin-conjugated PEG-coated biosynthesized gold nanoparticles (GNP-PEG-TRP) to triple-negative breast cancer (TNBC) cells. The adhesion is studied at the nanoscale using a combination of atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulations. The AFM measurements showed that the triptorelin-functionalized gold nanoparticles (GNP-TRP and GNP-PEG-TRP) have higher adhesion to triple-negative breast cancer cells (TNBC) than non-tumorigenic breast cells. The increased adhesion of GNP-TRP and GNP-PEG-TRP to TNBC is also attributed to the overexpression of LHRH receptors on the surfaces of both TNBC. Finally, the molecular dynamics model reveals insights into the effects of receptor density, molecular configuration, and receptor-ligand docking characteristics on the interactions of triptorelin-functionalized PEG-coated gold nanoparticles with TNBC. A three to nine-fold increase in the adhesion is predicted between triptorelin-functionalized PEG-coated gold nanoparticles and TNBC cells. The implications of the results are then discussed for the specific targeting of TNBC.
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Affiliation(s)
- Vanessa O Uzonwanne
- Department of Materials Science and Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA
| | - Arvand Navabi
- Department of Civil Engineering, Worcester Polytechnic Institute (WPI), Kaven Hall, 100 Institute Road, Worcester, MA 01609, USA
| | - John D Obayemi
- Department of Mechanical Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA; Department of Biomedical Engineering, Worcester Polytechnic Institute (WPI), Gateway Park, Life Sciences and Bioengineering Center, 60 Prescott Street, Worcester, MA 01605, USA
| | - Jingjie Hu
- Division of Vascular and Interventional Radiology, Mayo Clinic, 13400 East Shea Blvd., Scottsdale, AZ 85259, USA
| | - Ali A Salifu
- Department of Mechanical Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA; Department of Biomedical Engineering, Worcester Polytechnic Institute (WPI), Gateway Park, Life Sciences and Bioengineering Center, 60 Prescott Street, Worcester, MA 01605, USA
| | - Shahnaz Ghahremani
- Department of Biomedical Engineering, Worcester Polytechnic Institute (WPI), Gateway Park, Life Sciences and Bioengineering Center, 60 Prescott Street, Worcester, MA 01605, USA
| | - Nelson Ndahiro
- Department of Chemical Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA
| | - Nima Rahbar
- Department of Civil Engineering, Worcester Polytechnic Institute (WPI), Kaven Hall, 100 Institute Road, Worcester, MA 01609, USA
| | - Winston Soboyejo
- Department of Materials Science and Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA; Department of Mechanical Engineering, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 01609, USA; Department of Biomedical Engineering, Worcester Polytechnic Institute (WPI), Gateway Park, Life Sciences and Bioengineering Center, 60 Prescott Street, Worcester, MA 01605, USA.
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3
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Targeting luteinizing hormone-releasing hormone: A potential therapeutics to treat gynecological and other cancers. J Control Release 2018; 269:277-301. [DOI: 10.1016/j.jconrel.2016.11.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 01/05/2023]
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4
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Walencik PK, Stokowa-Sołtys K, Wieczorek R, Komarnicka UK, Kyzioł A, Jeżowska-Bojczuk M. Impact of the Cu(II) ions on the chemical and biological properties of goserelin – coordination pattern, DNA degradation, oxidative reactivity and in vitro cytotoxicity. J Inorg Biochem 2017; 175:167-178. [DOI: 10.1016/j.jinorgbio.2017.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/12/2017] [Accepted: 07/16/2017] [Indexed: 10/19/2022]
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Flanagan CA, Manilall A. Gonadotropin-Releasing Hormone (GnRH) Receptor Structure and GnRH Binding. Front Endocrinol (Lausanne) 2017; 8:274. [PMID: 29123501 PMCID: PMC5662886 DOI: 10.3389/fendo.2017.00274] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/28/2017] [Indexed: 12/22/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) regulates reproduction. The human GnRH receptor lacks a cytoplasmic carboxy-terminal tail but has amino acid sequence motifs characteristic of rhodopsin-like, class A, G protein-coupled receptors (GPCRs). This review will consider how recent descriptions of X-ray crystallographic structures of GPCRs in inactive and active conformations may contribute to understanding GnRH receptor structure, mechanism of activation and ligand binding. The structures confirmed that ligands bind to variable extracellular surfaces, whereas the seven membrane-spanning α-helices convey the activation signal to the cytoplasmic receptor surface, which binds and activates heterotrimeric G proteins. Forty non-covalent interactions that bridge topologically equivalent residues in different transmembrane (TM) helices are conserved in class A GPCR structures, regardless of activation state. Conformation-independent interhelical contacts account for a conserved receptor protein structure and their importance in the GnRH receptor structure is supported by decreased expression of receptors with mutations of residues in the network. Many of the GnRH receptor mutations associated with congenital hypogonadotropic hypogonadism, including the Glu2.53(90) Lys mutation, involve amino acids that constitute the conserved network. Half of the ~250 intramolecular interactions in GPCRs differ between inactive and active structures. Conformation-specific interhelical contacts depend on amino acids changing partners during activation. Conserved inactive conformation-specific contacts prevent receptor activation by stabilizing proximity of TM helices 3 and 6 and a closed G protein-binding site. Mutations of GnRH receptor residues involved in these interactions, such as Arg3.50(139) of the DRY/S motif or Tyr7.53(323) of the N/DPxxY motif, increase or decrease receptor expression and efficiency of receptor coupling to G protein signaling, consistent with the native residues stabilizing the inactive GnRH receptor structure. Active conformation-specific interhelical contacts stabilize an open G protein-binding site. Progress in defining the GnRH-binding site has recently slowed, with evidence that Tyr6.58(290) contacts Tyr5 of GnRH, whereas other residues affect recognition of Trp3 and Gly10NH2. The surprisingly consistent observations that GnRH receptor mutations that disrupt GnRH binding have less effect on "conformationally constrained" GnRH peptides may now be explained by crystal structures of agonist-bound peptide receptors. Analysis of GPCR structures provides insight into GnRH receptor function.
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Affiliation(s)
- Colleen A. Flanagan
- Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- *Correspondence: Colleen A. Flanagan,
| | - Ashmeetha Manilall
- Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
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Nakamura T, Ramos-Álvarez I, Iordanskaia T, Moreno P, Mantey SA, Jensen RT. Molecular basis for high affinity and selectivity of peptide antagonist, Bantag-1, for the orphan BB3 receptor. Biochem Pharmacol 2016; 115:64-76. [PMID: 27346274 DOI: 10.1016/j.bcp.2016.06.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/21/2016] [Indexed: 12/15/2022]
Abstract
Bombesin-receptor-subtype-3 (BB3 receptor) is a G-protein-coupled-orphan-receptor classified in the mammalian Bombesin-family because of high homology to gastrin-releasing peptide (BB2 receptor)/neuromedin-B receptors (BB1 receptor). There is increased interest in BB3 receptor because studies primarily from knockout-mice suggest it plays roles in energy/glucose metabolism, insulin-secretion, as well as motility and tumor-growth. Investigations into its roles in physiological/pathophysiological processes are limited because of lack of selective ligands. Recently, a selective, peptide-antagonist, Bantag-1, was described. However, because BB3 receptor has low-affinity for all natural, Bn-related peptides, little is known of the molecular basis of its high-affinity/selectivity. This was systematically investigated in this study for Bantag-1 using a chimeric-approach making both Bantag-1 loss-/gain-of-affinity-chimeras, by exchanging extracellular (EC) domains of BB3/BB2 receptor, and using site-directed-mutagenesis. Receptors were transiently expressed and affinities determined by binding studies. Bantag-1 had >5000-fold selectivity for BB3 receptor over BB2/BB1 receptors and substitution of the first EC-domain (EC1) in loss-/gain-of affinity-chimeras greatly affected affinity. Mutagenesis of each amino acid difference in EC1 between BB3 receptor/BB2 receptor showed replacement of His(107) in BB3 receptor by Lys(107) (H107K-BB3 receptor-mutant) from BB2 receptor, decreased affinity 60-fold, and three replacements [H107K, E11D, G112R] decreased affinity 500-fold. Mutagenesis in EC1's surrounding transmembrane-regions (TMs) demonstrated TM2 differences were not important, but R127Q in TM3 alone decreased affinity 400-fold. Additional mutants in EC1/TM3 explored the molecular basis for these changes demonstrated in EC1, particularly important is the presence of aromatic-interactions by His(107), rather than hydrogen-bonding or charge-charge interactions, for determining Bantag-1 high affinity/selectivity. In regard to Arg(127) in TM3, both hydrogen-bonding and charge-charge interactions contribute to the high-affinity/selectivity for Bantag-1.
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Affiliation(s)
- Taichi Nakamura
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
| | - Irene Ramos-Álvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
| | - Tatiana Iordanskaia
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
| | - Paola Moreno
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
| | - Samuel A Mantey
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
| | - R T Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA.
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Mayevu NMI, Choe H, Abagyan R, Seong JY, Millar RP, Katz AA, Flanagan CA. Histidine(7.36(305)) in the conserved peptide receptor activation domain of the gonadotropin releasing hormone receptor couples peptide binding and receptor activation. Mol Cell Endocrinol 2015; 402:95-106. [PMID: 25583361 DOI: 10.1016/j.mce.2015.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 01/06/2015] [Accepted: 01/06/2015] [Indexed: 12/29/2022]
Abstract
Transmembrane helix seven residues of G protein-coupled receptors (GPCRs) couple agonist binding to a conserved receptor activation mechanism. Amino-terminal residues of the GnRH peptide determine agonist activity. We investigated GnRH interactions with the His(7.36(305)) residue of the GnRH receptor, using functional and computational analysis of modified GnRH receptors and peptides. Non-polar His(7.36(305)) substitutions decreased receptor affinity for GnRH four- to forty-fold, whereas GnRH signaling potency was more decreased (~150-fold). Uncharged polar His(7.36(305)) substitutions decreased GnRH potency, but not affinity. [2-Nal(3)]-GnRH retained high affinity at receptors with non-polar His(7.36(305)) substitutions, supporting a role for His(7.36(305)) in recognizing Trp(3) of GnRH. Compared with GnRH, [2-Nal(3)]-GnRH potency was lower at the wild type GnRH receptor, but unchanged or higher at mutant receptors. Results suggest that His(7.36(305)) of the GnRH receptor forms two distinct interactions that determine binding to Trp(3) and couple agonist binding to the conserved transmembrane domain network that activates GPCRs.
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Affiliation(s)
- Nkateko M I Mayevu
- Medical Research Council Receptor Biology Research Unit, Institute of Infectious Diseases and Molecular Medicine, Division of Medical Biochemistry, University of Cape Town Health Sciences Faculty, Observatory, Cape Town 7925, South Africa
| | - Han Choe
- Department of Physiology and Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Ruben Abagyan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92039, USA
| | - Jae Young Seong
- Graduate School of Medicine, Korea University, Seoul 136-705, Korea
| | - Robert P Millar
- Medical Research Council Receptor Biology Research Unit, Institute of Infectious Diseases and Molecular Medicine, Division of Medical Biochemistry, University of Cape Town Health Sciences Faculty, Observatory, Cape Town 7925, South Africa; Mammal Research Institute, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
| | - Arieh A Katz
- Medical Research Council Receptor Biology Research Unit, Institute of Infectious Diseases and Molecular Medicine, Division of Medical Biochemistry, University of Cape Town Health Sciences Faculty, Observatory, Cape Town 7925, South Africa
| | - Colleen A Flanagan
- Medical Research Council Receptor Biology Research Unit, Institute of Infectious Diseases and Molecular Medicine, Division of Medical Biochemistry, University of Cape Town Health Sciences Faculty, Observatory, Cape Town 7925, South Africa; School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Private bag 3, Wits 2050, South Africa.
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8
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Wang J, Yadav V, Smart AL, Tajiri S, Basit AW. Toward Oral Delivery of Biopharmaceuticals: An Assessment of the Gastrointestinal Stability of 17 Peptide Drugs. Mol Pharm 2015; 12:966-73. [DOI: 10.1021/mp500809f] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Jie Wang
- Department of Pharmaceutics, UCL
School of Pharmacy, University College London, WC1N 1AX London, U.K
| | - Vipul Yadav
- Department of Pharmaceutics, UCL
School of Pharmacy, University College London, WC1N 1AX London, U.K
| | - Alice L. Smart
- Department of Pharmaceutics, UCL
School of Pharmacy, University College London, WC1N 1AX London, U.K
| | - Shinichiro Tajiri
- Department of Pharmaceutics, UCL
School of Pharmacy, University College London, WC1N 1AX London, U.K
| | - Abdul W. Basit
- Department of Pharmaceutics, UCL
School of Pharmacy, University College London, WC1N 1AX London, U.K
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Laimou D, Katsila T, Matsoukas J, Schally A, Gkountelias K, Liapakis G, Tamvakopoulos C, Tselios T. Rationally designed cyclic analogues of luteinizing hormone-releasing hormone: enhanced enzymatic stability and biological properties. Eur J Med Chem 2012; 58:237-47. [PMID: 23127987 DOI: 10.1016/j.ejmech.2012.09.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 09/24/2012] [Accepted: 09/27/2012] [Indexed: 11/18/2022]
Abstract
This article describes the rational design, synthesis and pharmacological properties of amide-linked cyclic analogues of Luteinizing Hormone-Releasing Hormone (LHRH) with substitutions at positions 1 (Pro), 6 (D-Leu/D-Trp), 9 (Aze) and 10 (BABA/Acp). These LHRH analogues fulfil the conformational requirements that are known in the literature (bend in the 5-8 segment) to be essential for receptor recognition and activation. Although, they are characterised by an overall low binding affinity to the LHRH-I receptor, the cyclic analogues that were studied and especially the cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH, exhibit a profoundly enhanced in vitro and in vivo stability and improved pharmacokinetics in comparison with their linear counterpart and leuprolide. Upon receptor binding, cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH causes testosterone release in C57/B16 mice (in vivo efficacy) that is comparable to that of leuprolide. Testosterone release is an acutely dose dependent effect that is blocked by the LHRH-I receptor antagonist, cetrorelix. The pharmacokinetic advantages and efficacy of cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH render this analogue a promising platform for future rational drug design studies towards the development of non-peptide LHRH mimetics.
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Affiliation(s)
- Despina Laimou
- Department of Chemistry, University of Patras, GR-26500 Patras, Greece
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10
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Ulloa-Aguirre A, Michael Conn P. Pharmacoperones: a new therapeutic approach for diseases caused by misfolded G protein-coupled receptors. ACTA ACUST UNITED AC 2012; 5:13-24. [PMID: 22074574 DOI: 10.2174/187221411794351851] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 11/13/2010] [Indexed: 01/10/2023]
Abstract
G Protein-coupled receptors (GPCRs) are cell membrane proteins that recognize specific chemical signals such as drugs and hormones and transduce these signals into cellular responses by activating G-proteins. As is the case for all newly synthesized proteins, GPCRs are subjected to conformational scrutiny at the endoplasmic reticulum prior to processing and trafficking to the cell surface membrane. Because of this stringent quality control screening mechanism, mutations that result in protein misfolding frequently lead to retention in the endoplasmic reticulum, aggregation or other misrouting and, eventually, to disease. This article reviews some patents and new therapeutic opportunities based on the misfolding and retention of otherwise functional GPCRs that represent promising approaches to correct conformational abnormalities leading to distinct disease states.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Research Unit in Reproductive Medicine, Hospital de Ginecobstetricia Luis Castelazo Ayala, Instituto Mexicano del Seguro Social, Av. Rio Magdalena 289, 60. piso, Col. Tizapan San Angel, C.P. 01090, Mexico D.F., Mexico.
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11
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Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
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12
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Saleh-Abady MM, Naderi-Manesh H, Alizadeh A, Shamsipour F, Balalaie S, Arabanian A. Anticancer activity of a new gonadotropin releasing hormone analogue. Biopolymers 2010; 94:292-7. [PMID: 19908246 DOI: 10.1002/bip.21335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Gonadotropin releasing hormone (GnRH) has a pivotal role in the biology of reproduction processes. In extrapituitary compartments GnRH and its receptor act as a part of the autocrin regulatory system of cell proliferation, resulting in its anticancer activity. Here the anticancer activity of a new analogue of GnRH has been investigated. Results indicate that proliferation of human breast and ovarian cancer cell lines is dose-dependently inhibited. The inhibitory efficiency of this new analogue is proved to be higher than the original triptorelin. In addition to its antimitogenic activity, evidence was found for the involvement of the apoptotic mechanism in the action of the new analogue. Furthermore the presence of chemical groups in the peptide sequence is thought to increase the protease stability of the new analogue in comparison with triptorelin. Consequently our new analogue can be considered as a good pharmaceutical candidate.
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13
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Structural elucidation of Leuprolide and its analogues in solution: insight into their bioactive conformation. Amino Acids 2010; 39:1147-60. [DOI: 10.1007/s00726-010-0549-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 02/25/2010] [Indexed: 11/25/2022]
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Ayala Yáñez R, Conn PM. Protein disulfide isomerase chaperone ERP-57 decreases plasma membrane expression of the human GnRH receptor. Cell Biochem Funct 2010; 28:66-73. [PMID: 20029959 DOI: 10.1002/cbf.1622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retention of misfolded proteins by the endoplasmic reticulum (ER) is a quality control mechanism involving the participation of endogenous chaperones such as calnexin (CANX). CANX interacts with and restricts plasma membrane expression (PME) of the gonadotropin releasing hormone receptor (GnRHR), a G protein-coupled receptor. CANX also interacts with ERP-57 a thiol oxidoreductase chaperone present in the ER. CANX along with ERP-57 promotes the formation of disulfide bond bridges in nascent proteins. The human GnRH receptor (hGnRHR) is stabilized by two disulfide bond bridges (C(14)-C(200) and C(114)-C(196)), that, when broken, lead to a decrease in receptor expression at the plasma membrane. To determine if the presence of chaperones CANX and ERP-57 exerts an influence over membrane routing and second messenger activation, we assessed the effect of various mutants including those with broken disulfide bridges (Cys --> Ala) along with the hGnRHR. The effect of chaperones on mutants was insignificant, whereas the over expression of ERP-57 led to an hGnRHR retention. This effect was further enhanced by cotransfection with cDNA for CANX showing receptor retention by ERP-57 augmented by CANX, suggesting utilization of these chaperones for quality control of the GnRHR.
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15
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Conn PM, Ulloa-Aguirre A. Trafficking of G-protein-coupled receptors to the plasma membrane: insights for pharmacoperone drugs. Trends Endocrinol Metab 2010; 21:190-7. [PMID: 20005736 PMCID: PMC2831145 DOI: 10.1016/j.tem.2009.11.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/18/2022]
Abstract
G protein-coupled receptors (GPCRs) are among the most common potential targets for pharmacological design. Synthesized in the endoplasmic reticulum, they interact with endogenous chaperones that assist in folding (or can retain incorrectly folded proteins) and are transferred to the plasma membrane where they exert their physiological functions. We summarize trafficking of the gonadotropin-releasing hormone receptor (GnRHR) to the plasma membrane. The trafficking of GnRHR is among the best characterized due in part to its small size and the consequent ease of making mutant proteins. Human mutations that cause disease through the misrouting of GPCRs including GnRHR are also reviewed. Special emphasis is placed on therapeutic opportunities presented by pharmacological chaperone drugs, or pharmacoperones, that allow misrouted mutants to be routed correctly and restored to function.
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Affiliation(s)
- P Michael Conn
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA.
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Janovick JA, Patny A, Mosley R, Goulet MT, Altman MD, Rush TS, Cornea A, Conn PM. Molecular mechanism of action of pharmacoperone rescue of misrouted GPCR mutants: the GnRH receptor. Mol Endocrinol 2009; 23:157-68. [PMID: 19095769 PMCID: PMC2646616 DOI: 10.1210/me.2008-0384] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 12/08/2008] [Indexed: 12/22/2022] Open
Abstract
The human GnRH receptor (hGnRHR), a G protein-coupled receptor, is a useful model for studying pharmacological chaperones (pharmacoperones), drugs that rescue misfolded and misrouted protein mutants and restore them to function. This technique forms the basis of a therapeutic approach of rescuing mutants associated with human disease and restoring them to function. The present study relies on computational modeling, followed by site-directed mutagenesis, assessment of ligand binding, effector activation, and confocal microscopy. Our results show that two different chemical classes of pharmacoperones act to stabilize hGnRHR mutants by bridging residues D(98) and K(121). This ligand-mediated bridge serves as a surrogate for a naturally occurring and highly conserved salt bridge (E(90)-K(121)) that stabilizes the relation between transmembranes 2 and 3, which is required for passage of the receptor through the cellular quality control system and to the plasma membrane. Our model was used to reveal important pharmacophoric features, and then identify a novel chemical ligand, which was able to rescue a D(98) mutant of the hGnRHR that could not be rescued as effectively by previously known pharmacoperones.
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Affiliation(s)
- Jo Ann Janovick
- Oregon National Primate Research Center/Oregon Health Sciences University, Beaverton, Oregon 97006, USA
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17
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Paulini KW, Baasner S, Gerlach M, Polymeropoulos EE, Schmidt P, Schuster T, Teifel M, Guenther EG. Development of AEZS-115 (ZEN-019) by Optimization of Structurally Unique, Orally Active, Peptidomimetic GnRH Antagonists. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 611:521-2. [DOI: 10.1007/978-0-387-73657-0_227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Jardón-Valadez E, Ulloa-Aguirre A, Piñeiro A. Modeling and molecular dynamics simulation of the human gonadotropin-releasing hormone receptor in a lipid bilayer. J Phys Chem B 2008; 112:10704-13. [PMID: 18680336 DOI: 10.1021/jp800544x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In the present study, a model for the human gonadotropin-releasing hormone receptor embedded in an explicit lipid bilayer was developed. The final conformation was obtained by extensive molecular dynamics simulations of a homology model based on the bovine rhodopsin crystal structure. The analysis of the receptor structure allowed us to detect a number of specific contacts between different amino acid residues, as well as water- and lipid-mediated interactions. These interactions were stable in six additional independent 35 ns long simulations at 310 and 323 K, which used the refined model as the starting structure. All loops, particularly the extracellular loop 2 and the intracellular loop 3, exhibited high fluctuations, whereas the transmembrane helices were more static. Although other models of this receptor have been previously developed, none of them have been subjected to extensive molecular dynamics simulations, and no other three-dimensional structure is publicly available. Our results suggest that the presence of ions as well as explicit solvent and lipid molecules are critical for the structure of membrane protein models, and that molecular dynamics simulations are certainly useful for their refinement.
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Affiliation(s)
- Eduardo Jardón-Valadez
- Research Unit in Reproductive Medicine, Hospital de Ginecobstetricia Luis Castelazo Ayala, Instituto Mexicano del Seguro Social, Mexico D.F. 01090, Mexico
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19
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Pfleger KDG, Pawson AJ, Millar RP. Changes to gonadotropin-releasing hormone (GnRH) receptor extracellular loops differentially affect GnRH analog binding and activation: evidence for distinct ligand-stabilized receptor conformations. Endocrinology 2008; 149:3118-29. [PMID: 18356273 DOI: 10.1210/en.2008-0002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GnRH and its structural variants bind to GnRH receptors from different species with different affinities and specificities. By investigating chimeric receptors that combine regions of mammalian and nonmammalian GnRH receptors, a greater understanding of how different domains influence ligand binding and receptor activation can be achieved. Using human-catfish and human-chicken chimeric receptors, we demonstrate the importance of extracellular loop conformation for ligand binding and agonist potency, providing further evidence for GnRH and GnRH II stabilization of distinct active receptor conformations. We demonstrate examples of GnRH receptor gain-of-function mutations that apparently improve agonist potency independently of affinity, implicating a role for extracellular loops in stabilizing the inactive receptor conformation. We also show that entire extracellular loop substitution can overcome the detrimental effects of localized mutations, thereby demonstrating the importance of considering the conformation of entire domains when drawing conclusions from point-mutation studies. Finally, we present evidence implicating the configuration of extracellular loops 2 and 3 in combination differentiating GnRH analog binding modes. Because there are two endogenous forms of GnRH ligand but only one functional form of full-length GnRH receptor in humans, understanding how GnRH and GnRH II can elicit distinct functional effects through the same receptor is likely to provide important insights into how these ligands can have differential effects in both physiological and pathological situations.
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Affiliation(s)
- Kevin D G Pfleger
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom.
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20
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Schottelius M, Berger S, Poethko T, Schwaiger M, Wester HJ. Development of Novel68Ga- and18F-Labeled GnRH-I Analogues with High GnRHR-Targeting Efficiency. Bioconjug Chem 2008; 19:1256-68. [DOI: 10.1021/bc800058k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Margret Schottelius
- Nuklearmedizinische Klinik and Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - Sebastian Berger
- Nuklearmedizinische Klinik and Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - Thorsten Poethko
- Nuklearmedizinische Klinik and Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - Markus Schwaiger
- Nuklearmedizinische Klinik and Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - Hans-Jürgen Wester
- Nuklearmedizinische Klinik and Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
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21
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Betz SF, Zhu YF, Chen C, Struthers RS. Non-Peptide Gonadotropin-Releasing Hormone Receptor Antagonists. J Med Chem 2008; 51:3331-48. [DOI: 10.1021/jm701249f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen F. Betz
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Yun-Fei Zhu
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Chen Chen
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - R. Scott Struthers
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
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22
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Bu L, Michino M, Wolf RM, Brooks CL. Improved model building and assessment of the Calcium-sensing receptor transmembrane domain. Proteins 2008; 71:215-26. [DOI: 10.1002/prot.21685] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Millar RP, Pawson AJ, Morgan K, Rissman EF, Lu ZL. Diversity of actions of GnRHs mediated by ligand-induced selective signaling. Front Neuroendocrinol 2008; 29:17-35. [PMID: 17976709 PMCID: PMC2667102 DOI: 10.1016/j.yfrne.2007.06.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 06/22/2007] [Accepted: 06/26/2007] [Indexed: 12/27/2022]
Abstract
Geoffrey Wingfield Harris' demonstration of hypothalamic hormones regulating pituitary function led to their structural identification and therapeutic utilization in a wide spectrum of diseases. Amongst these, Gonadotropin Releasing Hormone (GnRH) and its analogs are widely employed in modulating gonadotropin and sex steroid secretion to treat infertility, precocious puberty and many hormone-dependent diseases including endometriosis, uterine fibroids and prostatic cancer. While these effects are all mediated via modulation of the pituitary gonadotrope GnRH receptor and the G(q) signaling pathway, it has become increasingly apparent that GnRH regulates many extrapituitary cells in the nervous system and periphery. This review focuses on two such examples, namely GnRH analog effects on reproductive behaviors and GnRH analog effects on the inhibition of cancer cell growth. For both effects the relative activities of a range of GnRH analogs is distinctly different from their effects on the pituitary gonadotrope and different signaling pathways are utilized. As there is only a single functional GnRH receptor type in man we have proposed that the GnRH receptor can assume different conformations which have different selectivity for GnRH analogs and intracellular signaling proteins complexes. This ligand-induced selective-signaling recruits certain pathways while by-passing others and has implications in developing more selective GnRH analogs for highly specific therapeutic intervention.
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Affiliation(s)
- Robert P Millar
- MRC Human Reproductive Sciences Unit, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
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24
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Heitman LH, Oosterom J, Bonger KM, Timmers CM, Wiegerinck PHG, Ijzerman AP. [3H]Org 43553, the first low-molecular-weight agonistic and allosteric radioligand for the human luteinizing hormone receptor. Mol Pharmacol 2007; 73:518-24. [PMID: 17989351 DOI: 10.1124/mol.107.039875] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The luteinizing hormone (LH) receptor plays a pivotal role in reproduction. The high-molecular-weight (HMW) human chorionic gonadotropin (hCG) and LH are the endogenous ligands of this receptor and bind to its large N terminus. The present study characterizes the binding of a new low-molecular-weight (LMW) radioligand, [(3)H]5-amino-2-methylsulfanyl-4-[3-(2-morpholin-4-yl-acetylamino)-phenyl]-thieno[2,3-d]pyrimidine-6-carboxylic acid tert-butylamide (Org 43553), at the LH receptor. Equilibrium saturation and displacement assays were developed and optimized. Specific binding of [(3)H]Org 43553 to CHO-K1 cell membranes expressing the human LH receptor and a cAMP response element-luciferase reporter gene was saturable with a K(D) value of 2.4 +/- 0.4 nM and a B(max) value of 1.6 +/- 0.2 pmol/mg protein. Affinities of five LMW analogs of Org 43553 were determined. All displaced the radioligand competitively, with K(i) values ranging from 3.3 to 100 nM. Finally, the potency of these compounds in a cAMP-induced luciferase assay was also determined. There was a high correlation between affinity and potency (r = 0.99; P < 0.0001) of these compounds. In the search for LMW ligands, which bind allosterically to the seven-transmembrane domain of the LH receptor, a HMW radioligand (e.g., (125)I-hCG) is not suitable as it is not displaced by a LMW compound. Therefore, [(3)H]Org 43553, a new radioligand with good binding properties, allows screening for new LMW ligands that mimic the action of the endogenous hormone at the LH receptor.
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Affiliation(s)
- Laura H Heitman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, University of Leiden, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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25
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Stewart AJ, Sellar R, Wilson DJ, Millar RP, Lu ZL. Identification of a Novel Ligand Binding Residue Arg38(1.35)in the Human Gonadotropin-Releasing Hormone Receptor. Mol Pharmacol 2007; 73:75-81. [DOI: 10.1124/mol.107.040816] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Conn PM, Ulloa-Aguirre A, Ito J, Janovick JA. G Protein-Coupled Receptor Trafficking in Health and Disease: Lessons Learned to Prepare for Therapeutic Mutant Rescue in Vivo. Pharmacol Rev 2007; 59:225-50. [PMID: 17878512 DOI: 10.1124/pr.59.3.2] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
G protein-coupled receptors (GPCR) comprise the largest family of drug targets. This is not surprising as many signaling systems rely on this class of receptor to convert external and internal stimuli to intracellular responses. As is the case with other membrane proteins, GPCRs are subjected to a stringent quality control mechanism at the endoplasmic reticulum, which ensures that only correctly folded proteins enter the secretory pathway. Because of this quality control system, point mutations resulting in protein sequence variations may result in the production of misfolded and disease-causing proteins that are unable to reach their functional destinations in the cell. There is now a wealth of information demonstrating the functional rescue of misfolded mutant receptors by small nonpeptide molecules originally designed to serve as receptor antagonists; these small molecules ("pharmacoperones") serve as molecular templates, promoting correct folding and allowing the mutants to pass the scrutiny of the cellular quality control system and be expressed at the cell surface membrane. Two of these systems are especially well characterized: the gonadotropin-releasing hormone and the vasopressin type 2 receptors, which play important roles in regulating reproduction and water homeostasis, respectively. Mutations in these receptors can lead to well defined diseases that are recognized as being caused by receptor misfolding that may potentially be amenable to treatment with pharmacoperones. This review is focused on protein misfolding and misrouting related to various disease states, with special emphasis on these two receptors, which have proved to be of value for development of drugs potentially useful in regulating GPCR trafficking in healthy and disease states.
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Affiliation(s)
- P Michael Conn
- Divisions of Neuroscience and Reproductive Biology, ONPRC/OHSU, Beaverton, OR 97006, USA.
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27
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Lu ZL, Coetsee M, White CD, Millar RP. Structural determinants for ligand-receptor conformational selection in a peptide G protein-coupled receptor. J Biol Chem 2007; 282:17921-9. [PMID: 17452338 DOI: 10.1074/jbc.m610413200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein coupled receptors (GPCRs) modulate the majority of physiological processes through specific intermolecular interactions with structurally diverse ligands and activation of differential intracellular signaling. A key issue yet to be resolved is how GPCRs developed selectivity and diversity of ligand binding and intracellular signaling during evolution. We have explored the structural basis of selectivity of naturally occurring gonadotropin-releasing hormones (GnRHs) from different species in the single functional human GnRH receptor. We found that the highly variable amino acids in position 8 of the naturally occurring isoforms of GnRH play a discriminating role in selecting receptor conformational states. The human GnRH receptor has a higher affinity for the cognate GnRH I but a lower affinity for GnRH II and GnRHs from other species possessing substitutions for Arg(8). The latter were partial agonists in the human GnRH receptor. Mutation of Asn(7.45) in transmembrane domain (TM) 7 had no effect on GnRH I affinity but specifically increased affinity for other GnRHs and converted them to full agonists. Using molecular modeling and site-directed mutagenesis, we demonstrated that the highly conserved Asn(7.45) makes intramolecular interactions with a highly conserved Cys(6.47) in TM 6, suggesting that disruption of this intramolecular interaction induces a receptor conformational change which allosterically alters ligand specific binding sites and changes ligand selectivity and signaling efficacy. These results reveal GnRH ligand and receptor structural elements for conformational selection, and support co-evolution of GnRH ligand and receptor conformations.
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Affiliation(s)
- Zhi-Liang Lu
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, United Kingdom.
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28
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Chapter 12 Principles of G-Protein Coupled Receptor Modeling for Drug Discovery. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1574-1400(07)03012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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29
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Mamputha S, Lu ZL, Roeske RW, Millar RP, Katz AA, Flanagan CA. Conserved amino acid residues that are important for ligand binding in the type I gonadotropin-releasing hormone (GnRH) receptor are required for high potency of GnRH II at the type II GnRH receptor. Mol Endocrinol 2006; 21:281-92. [PMID: 16973761 DOI: 10.1210/me.2006-0150] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GnRH I regulates reproduction. A second form, designated GnRH II, selectively binds type II GnRH receptors. Amino acids of the type I GnRH receptor required for binding of GnRH I (Asp2.61(98), Asn2.65(102), and Lys3.32(121)) are conserved in the type II GnRH receptor, but their roles in receptor function are unknown. We have delineated their functions using mutagenesis, signaling and binding assays, immunoblotting, and computational modeling. Mutating Asp2.61(97) to Glu or Ala, Asn2.65(101) to Ala, or Lys3.32(120) to Gln decreased potency of GnRH II-stimulated inositol phosphate production. Consistent with proposed roles in ligand recognition, mutations eliminated measurable binding of GnRH II, whereas expression of mutant receptors was not decreased. In detailed analysis of how these residues affect ligand-dependent signaling, [Trp2]-GnRH I showed lesser decreases in potency than GnRH I at the Asp2.61(97)Glu mutant. In contrast, [Trp2]-GnRH II showed the same loss of potency as GnRH II at this mutant. This suggests that Asp2.61(97) contributes to recognition of His2 of GnRH I, but not of GnRH II. GnRH II showed a large decrease in potency at the Asn2.65(101)Ala mutant compared with analogs lacking the CO group of Gly10NH2. This suggests that Asn2.65(101) recognizes Gly10NH2 of GnRH II. GnRH agonists showed large decreases in potency at the Lys3.32(120)Gln mutant, but antagonist activity was unaffected. This suggests that Lys3.32(120) recognizes agonists, but not antagonists, as in the type I receptor. These data indicate that roles of conserved residues are similar, but not identical, in the type I and II GnRH receptors.
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Affiliation(s)
- Sipho Mamputha
- Medical Research Council/University of Cape Town Research Group for Receptor Biology, Institute for Infectious Diseases and Molecular Medicine and Division of Medical Biochemistry, Cape Town, South Africa
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30
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Model of gonadotropin-releasing hormone and gonadotropin-releasing hormone complex. SEXUALITY AND DISABILITY 2006. [DOI: 10.1007/s11195-006-9018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Betz SF, Reinhart GJ, Lio FM, Chen C, Struthers RS. Overlapping, Nonidentical Binding Sites of Different Classes of Nonpeptide Antagonists for the Human Gonadotropin-Releasing Hormone Receptor. J Med Chem 2005; 49:637-47. [PMID: 16420049 DOI: 10.1021/jm0506928] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peptide agonists and antagonists of the human gonadotropin-releasing hormone receptor (GnRH-R) are widely used to treat a range of reproductive hormone related diseases. Recently, nonpeptide, orally available GnRH-R antagonists have emerged from several chemical classes. To understand how a relatively large peptide-binding pocket can recognize numerous nonpeptide ligands, we undertook a systematic mapping of GnRH-R residues involved in the binding of three nonpeptide antagonists. A region composed of the extracellular portions of transmembrane helices 6 and 7, extracellular loop 3, and the N-terminal domain significantly contributed to nonpeptide antagonist binding. However, each molecule was affected by a different subset of residues in these regions, indicating that each appears to occupy distinct, partially overlapping subregions within the more extensive peptide-binding pocket. Moreover, the resulting receptor interaction maps provide a basis to begin to reconcile structure-activity relationships between various nonpeptide and peptide series and facilitate the design of improved therapeutic agents.
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Affiliation(s)
- Stephen F Betz
- Department of Endocrinology, Neurocrine Biosciences, Inc., San Diego, California 92130, USA.
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Fanelli F, De Benedetti PG. Computational Modeling Approaches to Structure−Function Analysis of G Protein-Coupled Receptors. Chem Rev 2005; 105:3297-351. [PMID: 16159154 DOI: 10.1021/cr000095n] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute and Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41100 Modena, Italy.
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