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Ericson MD, Freeman KT, Larson CM, Bouchard JL, John K, Lunzer MM, Koerperich ZM, Haskell-Luevano C. Incorporation of Three Extracyclic Arginine Residues into a Melanocortin Macrocyclic Agonist (c[Pro-His-DPhe-Arg-Trp-Dap-Lys(Arg-Arg-Arg-Ac)-DPro]) Decreases Food Intake When Administered Intrathecally or Subcutaneously Compared to a Macrocyclic Ligand Lacking Extracyclic Arginine Residues (c[Pro-His-DPhe-Arg-Trp-Dap-Ala-DPro)]. ACS Pharmacol Transl Sci 2024; 7:1114-1125. [PMID: 38633589 PMCID: PMC11020072 DOI: 10.1021/acsptsci.4c00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/19/2024]
Abstract
Of the three Food and Drug Administration-approved melanocortin peptide drugs, two possess a cyclic scaffold, demonstrating that cyclized melanocortin peptides have therapeutic relevance. An extracyclic Arg residue, critical for pharmacological activity in the approved melanocortin cyclic drug setmelanotide, has also been demonstrated to increase the signal when fluorescently labeled cell-penetrating cyclic peptides are incubated with HeLa cells, with the maximal signal observed with three extracyclic Arg amino acids. Herein, a branching Lys residue was substituted into two macrocyclic melanocortin peptide agonists to incorporate 0-3 extracyclic Arg amino acids. Incorporation of the Arg residues resulted in equipotent or increased agonist potency at the mouse melanocortin receptors in vitro, suggesting that these substitutions were tolerated in the macrocyclic scaffolds. Further in vivo evaluation of one parent ligand (c[Pro-His-DPhe-Arg-Trp-Dap-Ala-Pro]) and the three Arg derivative (c[Pro-His-DPhe-Arg-Trp-Dap-Lys(Ac-Arg-Arg-Arg)-Pro)] demonstrated that the three Arg derivative further decreased food intake compared to the parent macrocycle when the compounds were administered either via intrathecal injection or subcutaneous dosing. This suggests that three extracyclic Arg amino acids may be beneficial in the design of cyclic melanocortin ligands and that in vitro pharmacological profiling may not predict the in vivo efficacy of melanocortin ligands.
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Affiliation(s)
- Mark D. Ericson
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Courtney M. Larson
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jacob L. Bouchard
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Kristen John
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mary M. Lunzer
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zoe M. Koerperich
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, Institute for Translational Neuroscience, University
of Minnesota, Minneapolis, Minnesota 55455, United States
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Sencanski M, Glisic S, Kubale V, Cotman M, Mavri J, Vrecl M. Computational Modeling and Characterization of Peptides Derived from Nanobody Complementary-Determining Region 2 (CDR2) Targeting Active-State Conformation of the β 2-Adrenergic Receptor (β 2AR). Biomolecules 2024; 14:423. [PMID: 38672440 PMCID: PMC11048008 DOI: 10.3390/biom14040423] [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: 02/27/2024] [Revised: 03/20/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
This study assessed the suitability of the complementarity-determining region 2 (CDR2) of the nanobody (Nb) as a template for the derivation of nanobody-derived peptides (NDPs) targeting active-state β2-adrenergic receptor (β2AR) conformation. Sequences of conformationally selective Nbs favoring the agonist-occupied β2AR were initially analyzed by the informational spectrum method (ISM). The derived NDPs in complex with β2AR were subjected to protein-peptide docking, molecular dynamics (MD) simulations, and metadynamics-based free-energy binding calculations. Computational analyses identified a 25-amino-acid-long CDR2-NDP of Nb71, designated P4, which exhibited the following binding free-energy for the formation of the β2AR:P4 complex (ΔG = -6.8 ± 0.8 kcal/mol or a Ki = 16.5 μM at 310 K) and mapped the β2AR:P4 amino acid interaction network. In vitro characterization showed that P4 (i) can cross the plasma membrane, (ii) reduces the maximum isoproterenol-induced cAMP level by approximately 40% and the isoproterenol potency by up to 20-fold at micromolar concentration, (iii) has a very low affinity to interact with unstimulated β2AR in the cAMP assay, and (iv) cannot reduce the efficacy and potency of the isoproterenol-mediated β2AR/β-arrestin-2 interaction in the BRET2-based recruitment assay. In summary, the CDR2-NDP, P4, binds preferentially to agonist-activated β2AR and disrupts Gαs-mediated signaling.
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Affiliation(s)
- Milan Sencanski
- Laboratory for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
- Laboratory for Bioinformatics and Computational Chemistry, Institute of Nuclear Sciences VINCA, National Institute of Serbia, University of Belgrade, 11000 Belgrade, Serbia;
| | - Sanja Glisic
- Laboratory for Bioinformatics and Computational Chemistry, Institute of Nuclear Sciences VINCA, National Institute of Serbia, University of Belgrade, 11000 Belgrade, Serbia;
| | - Valentina Kubale
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (V.K.); (M.C.)
| | - Marko Cotman
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (V.K.); (M.C.)
| | - Janez Mavri
- Department of Computational Biochemistry and Drug Design, National Institute of Chemistry, 1000 Ljubljana, Slovenia;
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (V.K.); (M.C.)
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3
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Calderón JC, Ibrahim P, Gobbo D, Gervasio FL, Clark T. Activation/Deactivation Free-Energy Profiles for the β 2-Adrenergic Receptor: Ligand Modes of Action. J Chem Inf Model 2023; 63:6332-6343. [PMID: 37824365 DOI: 10.1021/acs.jcim.3c00805] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
We use enhanced-sampling simulations with an effective collective variable to study the activation of the β2-adrenergic receptor in the presence of ligands with different efficacy. The free-energy profiles are computed for the ligand-free (apo) receptor and binary (apo-receptor + G-protein α-subunit and receptor + ligand) and ternary complexes. The results are not only compatible with available experiments but also allow unprecedented structural insight into the nature of GPCR conformations along the activation pathway and their role in the activation mechanism. In particular, the simulations reveal an unexpected mode of action of partial agonists such as salmeterol and salbutamol that arises already in the binary complex without the G-protein. Specific differences in the polar interactions with residues in TM5, which are required to stabilize an optimal TM6 conformation that facilitates G-protein binding and receptor activation, play a major role in differentiating them from full agonists.
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Affiliation(s)
- Jacqueline C Calderón
- Computer-Chemistry-Center, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nuernberg, Naegelsbachstraße 25, 91052 Erlangen, Germany
| | - Passainte Ibrahim
- Institute of Medical Physics and Biophysics, Faculty of Medicine, University of Leipzig, 04109 Leipzig, Germany
| | - Dorothea Gobbo
- Pharmaceutical Sciences, University of Geneva, CH1206 Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, CH1206 Geneva, Switzerland
| | - Francesco Luigi Gervasio
- Pharmaceutical Sciences, University of Geneva, CH1206 Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, CH1206 Geneva, Switzerland
- Chemistry Department, University College London, WC1H 0AJ London, United Kingdom
- Swiss Bioinformatics Institute, CH1206 Geneva, Switzerland
| | - Timothy Clark
- Computer-Chemistry-Center, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nuernberg, Naegelsbachstraße 25, 91052 Erlangen, Germany
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4
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Ericson MD, Doering SR, Larson CM, Freeman KT, LaVoi TM, Donow HM, Santos RG, Cho RH, Koerperich ZM, Giulianotti MA, Pinilla C, Houghten RA, Haskell-Luevano C. Functional Mixture-Based Positional Scan Identifies a Library of Antagonist Tetrapeptide Sequences (LAtTeS) with Nanomolar Potency for the Melanocortin-4 Receptor and Equipotent with the Endogenous AGRP(86-132) Antagonist. J Med Chem 2021; 64:14860-14875. [PMID: 34592820 DOI: 10.1021/acs.jmedchem.1c01417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The melanocortin-4 receptor (MC4R) plays an important role in appetite. Agonist ligands that stimulate the MC4R decrease appetite, while antagonist compounds increase food consumption. Herein, a functional mixture-based positional scan identified novel MC4R antagonist sequences. Mixtures comprising a library of 12,960,000 tetrapeptides were screened in the presence and absence of the NDP-MSH agonist. These results led to the synthesis of 48 individual tetrapeptides, of which 40 were screened for functional activity at the melanocortin receptors. Thirteen compounds were found to possess nanomolar antagonist potency at the MC4R, with the general tetrapeptide sequence Ac-Aromatic-Basic-Aromatic-Basic-NH2. The most notable results include the identification of tetrapeptide 48 [COR1-25, Ac-DPhe(pI)-Arg-Nal(2')-Arg-NH2], an equipotent MC4R antagonist to agouti-related protein [AGRP(86-132)], more potent than miniAGRP(87-120), and possessing 15-fold selectivity for the MC4R versus the MC3R. These tetrapeptides may serve as leads for novel appetite-inducing therapies to treat states of negative energy balance, such as cachexia and anorexia.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Skye R Doering
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Courtney M Larson
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T Freeman
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Travis M LaVoi
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Haley M Donow
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Radleigh G Santos
- Nova Southeastern University, 3301 College Avenue, Fort Lauderdale, Florida 33314, United States
| | - Rachel H Cho
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zoe M Koerperich
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Marc A Giulianotti
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Clemencia Pinilla
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Richard A Houghten
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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5
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Ericson MD, Haslach EM, Schnell SM, Freeman KT, Xiang ZM, Portillo FP, Speth R, Litherland SA, Haskell-Luevano C. Discovery of Molecular Interactions of the Human Melanocortin-4 Receptor (hMC4R) Asp189 (D189) Amino Acid with the Endogenous G-Protein-Coupled Receptor (GPCR) Antagonist Agouti-Related Protein (AGRP) Provides Insights to AGRP's Inverse Agonist Pharmacology at the hMC4R. ACS Chem Neurosci 2021; 12:542-556. [PMID: 33470098 DOI: 10.1021/acschemneuro.0c00755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The melanocortin receptors (MCRs) are important for numerous biological pathways, including feeding behavior and energy homeostasis. In addition to endogenous peptide agonists, this receptor family has two naturally occurring endogenous antagonists, agouti and agouti-related protein (AGRP). At the melanocortin-4 receptor (MC4R), the AGRP ligand functions as an endogenous inverse agonist in the absence of agonist and as a competitive antagonist in the presence of agonist. At the melanocortin-3 receptor (MC3R), AGRP functions solely as a competitive antagonist in the presence of agonist. The molecular interactions that differentiate AGRP's inverse agonist activity at the MC4R have remained elusive until the findings reported herein. Upon the basis of homology molecular modeling approaches, we previously postulated a unique interaction between the D189 position of the hMC4R and Asn114 of AGRP. To further test this hypothesis, six D189 mutant hMC4Rs (D189A, D189E, D189N, D189Q, D189S, and D189K) were generated and pharmacologically characterized resulting in the discovery of differences in inverse agonist activity of AGRP and an 11 macrocyclic compound library. These data support the hypothesized interaction between the hMC4R D189 position and Asn114 residue of AGRP and define critical ligand-receptor molecular interactions responsible for the inverse agonist activity of AGRP at the hMC4R.
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Affiliation(s)
- Mark D. Ericson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Erica M. Haslach
- Departments of Pharmacodynamics and Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Sathya M. Schnell
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Zhimin M. Xiang
- Departments of Pharmacodynamics and Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Frederico P. Portillo
- Departments of Pharmacodynamics and Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Robert Speth
- College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida 33328, United States
- College of Medicine, Georgetown University, Washington, D.C. 20057, United States
| | - Sally A. Litherland
- Translational Research, Florida Hospital Cancer Institute, Orlando, Florida 32804, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
- Departments of Pharmacodynamics and Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
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6
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Sencanski M, Glisic S, Šnajder M, Veljkovic N, Poklar Ulrih N, Mavri J, Vrecl M. Computational design and characterization of nanobody-derived peptides that stabilize the active conformation of the β 2-adrenergic receptor (β 2-AR). Sci Rep 2019; 9:16555. [PMID: 31719570 PMCID: PMC6851183 DOI: 10.1038/s41598-019-52934-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 10/26/2019] [Indexed: 12/15/2022] Open
Abstract
This study aimed to design and functionally characterize peptide mimetics of the nanobody (Nb) related to the β2-adrenergic receptor (β2-AR) (nanobody-derived peptide, NDP). We postulated that the computationally derived and optimized complementarity-determining region 3 (CDR3) of Nb is sufficient for its interaction with receptor. Sequence-related Nb-families preferring the agonist-bound active conformation of β2-AR were analysed using the informational spectrum method (ISM) and β2-AR:NDP complexes studied using protein-peptide docking and molecular dynamics (MD) simulations in conjunction with metadynamics calculations of free energy binding. The selected NDP of Nb71, designated P3, was 17 amino acids long and included CDR3. Metadynamics calculations yielded a binding free energy for the β2-AR:P3 complex of ΔG = (-7.23 ± 0.04) kcal/mol, or a Kd of (7.9 ± 0.5) μM, for T = 310 K. In vitro circular dichroism (CD) spectropolarimetry and microscale thermophoresis (MST) data provided additional evidence for P3 interaction with agonist-activated β2-AR, which displayed ~10-fold higher affinity for P3 than the unstimulated receptor (MST-derived EC50 of 3.57 µM vs. 58.22 µM), while its ability to inhibit the agonist-induced interaction of β2-AR with β-arrestin 2 was less evident. In summary, theoretical and experimental evidence indicated that P3 preferentially binds agonist-activated β2-AR.
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Affiliation(s)
- Milan Sencanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Sanja Glisic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Marko Šnajder
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nevena Veljkovic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | | | - Janez Mavri
- Laboratory of Computational Biochemistry and Drug Design, National Institute of Chemistry, Ljubljana, Slovenia
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia.
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7
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Susec M, Sencanski M, Glisic S, Veljkovic N, Pedersen C, Drinovec L, Stojan J, Nøhr J, Vrecl M. Functional characterization of β 2-adrenergic and insulin receptor heteromers. Neuropharmacology 2019; 152:78-89. [PMID: 30707913 DOI: 10.1016/j.neuropharm.2019.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/01/2019] [Accepted: 01/23/2019] [Indexed: 01/06/2023]
Abstract
This study aimed to functionally characterize β2-adrenergic (β2AR) and insulin receptor (IR) heteromers in regard to β-arrestin 2 (βarr2) recruitment and cAMP signaling and to examine the involvement of the cytoplasmic portion of the IR β chain in heteromerization with β2AR. Evidence for β2AR:IR:βarr2 complex formation and the specificity of the IR:βarr2 interaction was first provided by bioinfomatics analysis. Receptor-heteromer investigation technology (HIT) then provided functional evidence of β2AR:IR heterodimerization by showing isoproterenol-induced but not insulin-induced GFP2-βarr2 recruitment to the β2AR:IR complex; the IR:βarr2 interaction was found to only be constitutive. The constitutive IR:βarr2 BRET signal (BRETconst) was significantly smaller in cells coexpressing IR-RLuc8 and a GFP2-βarr2 1-185 mutant lacking the proposed IR binding domain. β2AR:IR heteromerization also influenced the pharmacological phenotype of β2AR, i.e., its efficacy in recruiting βarr2 and activating cAMP signaling. Evidence suggesting involvement of the cytoplasmic portion of the IR β chain in the interaction with β2AR was provided by BRET2 saturation and HIT assays using an IR 1-1271 stop mutant lacking the IR C-terminal tail region. For the complex consisting of IR 1-1271-RLuc8:β2AR-GFP2, saturation was not reached, most likely reflecting random collisions between IR 1-1271 and β2AR. Furthermore, in the HIT assay, no substantial agonist-induced increase in the BRET2 signal was detected that would be indicative of βarr2 recruitment to the IR 1-1271:β2AR heteromer. Complementary 3D visualization of β2AR:IR provided supporting evidence for stability of the heterotetramer complex and identified amino acid residues involved in β2AR:IR heteromerization. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.
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Affiliation(s)
- Maja Susec
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia
| | - Milan Sencanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Sanja Glisic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Nevena Veljkovic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Christina Pedersen
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Luka Drinovec
- Department of Condensed Matter Physics, Jožef Stefan Institute, Slovenia
| | - Jurij Stojan
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jane Nøhr
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia.
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Ericson MD, Freeman KT, Schnell SM, Haskell-Luevano C. A Macrocyclic Agouti-Related Protein/[Nle 4,DPhe 7]α-Melanocyte Stimulating Hormone Chimeric Scaffold Produces Subnanomolar Melanocortin Receptor Ligands. J Med Chem 2017; 60:805-813. [PMID: 28045525 DOI: 10.1021/acs.jmedchem.6b01707] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The melanocortin system consists of five receptor subtypes, endogenous agonists, and naturally occurring antagonists. These receptors and ligands have been implicated in numerous biological pathways including processes linked to obesity and food intake. Herein, a truncation structure-activity relationship study of chimeric agouti-related protein (AGRP)/[Nle4,DPhe7]α-melanocyte stimulating hormone (NDP-MSH) ligands is reported. The tetrapeptide His-DPhe-Arg-Trp or tripeptide DPhe-Arg-Trp replaced the Arg-Phe-Phe sequence in the AGRP active loop derivative c[Pro-Arg-Phe-Phe-Xxx-Ala-Phe-DPro], where Xxx was the native Asn of AGRP or a diaminopropionic (Dap) acid residue previously shown to increase antagonist potency at the mMC4R. The Phe, Ala, and Dap/Asn residues were successively removed to generate a 14-member library that was assayed for agonist activity at the mouse MC1R, MC3R, MC4R, and MC5R. Two compounds possessed nanomolar agonist potency at the mMC4R, c[Pro-His-DPhe-Arg-Trp-Asn-Ala-Phe-DPro] and c[Pro-His-DPhe-Arg-Trp-Dap-Ala-DPro], and may be further developed to generate novel melanocortin probes and ligands for understanding and treating obesity.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Katie T Freeman
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sathya M Schnell
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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9
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Dogra S, Sona C, Kumar A, Yadav PN. Tango assay for ligand-induced GPCR-β-arrestin2 interaction: Application in drug discovery. Methods Cell Biol 2015; 132:233-54. [PMID: 26928547 DOI: 10.1016/bs.mcb.2015.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
G protein-coupled receptors (GPCRs) are widely known to modulate almost all physiological functions and have been demonstrated over the time as therapeutic targets for wide gamut of diseases. The design and implementation of high-throughput GPCR-based assays that permit the efficient screening of large compound libraries to discover novel drug candidates are essential for a successful drug discovery endeavor. Usually, GPCR-based functional assays depend primarily on the measurement of G protein-mediated second messenger generation. However, with advent of advanced molecular biology tools and increased understanding of GPCR signal transduction, many G protein-independent pathways such as β-arrestin translocation are being utilized to detect the activity of GPCRs. These assays provide additional information on functional selectivity (also known as biased agonism) of compounds that could be harnessed to develop pathway-selective drug candidates to reduce the adverse effects associated with given GPCR target. In this chapter, we describe the basic principle, detailed methodologies and assay setup, result analysis and data interpretations of the β-arrestin2 Tango assay, and its comparison with cell-based G protein-dependent GPCR assays, which could be employed in a simple academic setup to facilitate GPCR-based drug discovery.
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Affiliation(s)
- Shalini Dogra
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Chandan Sona
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Ajeet Kumar
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Prem N Yadav
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
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10
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Tala SR, Schnell SM, Haskell-Luevano C. Microwave-assisted solid-phase synthesis of side-chain to side-chain lactam-bridge cyclic peptides. Bioorg Med Chem Lett 2015; 25:5708-11. [PMID: 26555357 DOI: 10.1016/j.bmcl.2015.10.095] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 11/25/2022]
Abstract
Side-chain to side-chain lactam-bridged cyclic peptides have been utilized as therapeutic agents and biochemical tools. Previous synthetic methods of these peptides need special reaction conditions, form side products and take longer reaction times. Herein, an efficient microwave-assisted synthesis of side-chain to side-chain lactam-bridge cyclic peptides SHU9119 and MTII is reported. The synthesis time and efforts are significantly reduced in the present method, without side product formation. The analytical and pharmacological data of the synthesized cyclic peptides are in accordance with the commercially obtained compounds. This new method could be used to synthesize other side-chain to side-chain lactam-bridge peptides and amenable to automation and extensive SAR compound derivatization.
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Affiliation(s)
- Srinivasa R Tala
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sathya M Schnell
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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11
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Ericson MD, Schnell SM, Freeman KT, Haskell-Luevano C. A fragment of the Escherichia coli ClpB heat-shock protein is a micromolar melanocortin 1 receptor agonist. Bioorg Med Chem Lett 2015; 25:5306-8. [PMID: 26433448 DOI: 10.1016/j.bmcl.2015.09.046] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 12/01/2022]
Abstract
The melanocortin system consists of five receptor subtypes (MC1-5R), endogenous agonists derived from the proopiomelanocortin gene transcript, and the antagonists agouti and agouti-related protein. The Escherichia coli heat shock protein ClpB has previously been described as an antigen mimetic to the endogenous melanocortin agonist α-MSH. Herein, we investigated if a fragment of the ClpB protein could directly signal through the melanocortin receptors. We synthesized a complementary fragment of the ClpB protein that partially aligned with α-MSH. Pharmacological assessment of this fragment resulted in no antagonist activity at the MC3R or the MC4R and no agonist activity at the MC4R. Partial receptor activation was observed for the MC3R and MC5R at 100 μM concentrations. This fragment was shown to be a full micromolar MC1R agonist and may serve as a template for future research into selective MC1R ligands.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Sathya M Schnell
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Katie T Freeman
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA.
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12
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Kawano K. [Stoichiometric analysis of oligomerization of membrane proteins using coiled-coil labeling and in-cell spectroscopy]. YAKUGAKU ZASSHI 2014; 134:931-7. [PMID: 25174363 DOI: 10.1248/yakushi.14-00162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many membrane proteins are responsible for signaling and ionic transport necessary to maintain biological functions in vivo. Recently, not only conformational changes but also oligomerization have been proposed to regulate protein activation. Thus, the study of membrane protein oligomerization is crucial for new drug development. The existing destructive methodologies such as immunoprecipitation, however, are not suitable to determine oligomeric states precisely because of the artificial aggregation of proteins after detergent solubilization. In the present study, the coiled-coil tag-probe labeling method and spectral imaging were first combined to establish a new methodology based on fluorescence resonance energy transfer (FRET) for stoichiometric analysis of the oligomeric states of membrane proteins on living cells. After validating the method for mono-, di-, and tetrameric standard membrane proteins, the oligomeric state of β₂-adrenergic receptors (β₂ARs) was examined to clarify its functional significance. It was found that β2ARs could transduce cyclic adenosine 5'-monophosphate (cAMP) signals and internalize them upon treatment with ligands without showing any FRET signals. Thus, β₂ARs do not form constitutive homooligomers, and homooligomerization is not necessary for the receptor function of β₂ARs. Finally, the oligomeric state of full-length M2 proton-selective channels of influenza A virus was investigated. Although the results of X-ray crystallography and NMR studies using fragment peptides suggested that M2 stably forms a tetrameric channel, the full-length M2 proteins formed proton-conducting dimers at neutral pH and these dimers were converted to tetramers at acidic pH, indicating that the minimal functional unit of the M2 channel is a dimer.
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Affiliation(s)
- Kenichi Kawano
- Department of Biophysical Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University
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13
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Johnston JM, Filizola M. Beyond standard molecular dynamics: investigating the molecular mechanisms of G protein-coupled receptors with enhanced molecular dynamics methods. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 796:95-125. [PMID: 24158803 PMCID: PMC4074508 DOI: 10.1007/978-94-007-7423-0_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The majority of biological processes mediated by G Protein-Coupled Receptors (GPCRs) take place on timescales that are not conveniently accessible to standard molecular dynamics (MD) approaches, notwithstanding the current availability of specialized parallel computer architectures, and efficient simulation algorithms. Enhanced MD-based methods have started to assume an important role in the study of the rugged energy landscape of GPCRs by providing mechanistic details of complex receptor processes such as ligand recognition, activation, and oligomerization. We provide here an overview of these methods in their most recent application to the field.
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Affiliation(s)
- Jennifer M. Johnston
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Marta Filizola
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
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14
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van der Westhuizen ET, Breton B, Christopoulos A, Bouvier M. Quantification of ligand bias for clinically relevant β2-adrenergic receptor ligands: implications for drug taxonomy. Mol Pharmacol 2013; 85:492-509. [PMID: 24366668 DOI: 10.1124/mol.113.088880] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The concepts of functional selectivity and ligand bias are becoming increasingly appreciated in modern drug discovery programs, necessitating more informed approaches to compound classification and, ultimately, therapeutic candidate selection. Using the β2-adrenergic receptor as a model, we present a proof of concept study that assessed the bias of 19 β-adrenergic ligands, including many clinically used compounds, across four pathways [cAMP production, extracellular signal-regulated kinase 1/2 (ERK1/2) activation, calcium mobilization, and receptor endocytosis] in the same cell background (human embryonic kidney 293S cells). Efficacy-based clustering placed the ligands into five distinct groups with respect to signaling signatures. In some cases, apparent functional selectivity originated from off-target effects on other endogenously expressed adrenergic receptors, highlighting the importance of thoroughly assessing selectivity of the responses before concluding receptor-specific ligand-biased signaling. Eliminating the nonselective compounds did not change the clustering of the 10 remaining compounds. Some ligands exhibited large differences in potency for the different pathways, suggesting that the nature of the receptor-effector complexes influences the relative affinity of the compounds for specific receptor conformations. Calculation of relative effectiveness (within pathway) and bias factors (between pathways) for each of the compounds, using an operational model of agonism, revealed a global signaling signature for all of the compounds relative to isoproterenol. Most compounds were biased toward ERK1/2 activation over the other pathways, consistent with the notion that many proximal effectors converge on this pathway. Overall, we demonstrate a higher level of ligand texture than previously anticipated, opening perspectives for the establishment of pluridimensional correlations between signaling profiles, drug classification, therapeutic efficacy, and safety.
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Affiliation(s)
- Emma T van der Westhuizen
- Department of Biochemistry and Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec, Canada (E.T.v.d.W., B.B., M.B.); and Drug Discovery Biology and Department of Pharmacology, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (E.T.v.d.W., A.C.)
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15
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Song YB, Park CO, Jeong JY, Huh WK. Monitoring G protein-coupled receptor activation using an adenovirus-based β-arrestin bimolecular fluorescence complementation assay. Anal Biochem 2013; 449:32-41. [PMID: 24361713 DOI: 10.1016/j.ab.2013.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/16/2013] [Accepted: 12/10/2013] [Indexed: 01/22/2023]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors and are involved in a variety of pathological conditions including cancer and cardiovascular, metabolic, neurological, and autoimmune diseases. GPCRs are being intensively investigated as targets for therapeutic intervention, and the β-arrestin recruitment assay has become a popular tool for analyzing GPCR activation. Here, we report a high-throughput method for cloning GPCR cDNAs into adenoviral bimolecular fluorescence complementation (BiFC) vectors and performing the β-arrestin BiFC assay in cells transduced with recombinant adenoviruses. An analysis of the activation of somatostatin receptor 2 (SSTR2) with the adenovirus-based β-arrestin BiFC assay showed that the assay is suitable for quantifying SSTR2 activation in response to specific agonists or antagonists. Furthermore, the adenovirus-based β-arrestin BiFC assay was able to detect the activation of a broad range of GPCRs. Collectively, our data indicate that the adenovirus-based β-arrestin BiFC assay can serve as a simple and universal platform for studying GPCR activation and thus will be useful for high-throughput screening of drugs that target GPCRs.
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Affiliation(s)
- Yong Bhum Song
- Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, Seoul 151-747, Republic of Korea
| | - Chul O Park
- Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, Seoul 151-747, Republic of Korea
| | - Jae-Yeon Jeong
- Marine Biotechnology Research Division, Korea Institute of Ocean Science & Technology, Ansan 426-744, Republic of Korea.
| | - Won-Ki Huh
- Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, Seoul 151-747, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul 151-747, Republic of Korea.
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16
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Kawano K, Yano Y, Omae K, Matsuzaki S, Matsuzaki K. Stoichiometric analysis of oligomerization of membrane proteins on living cells using coiled-coil labeling and spectral imaging. Anal Chem 2013; 85:3454-61. [PMID: 23427815 DOI: 10.1021/ac400177a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Many membrane proteins are proposed to work as oligomers; however, the conclusion is sometimes controversial, as for β2-adorenergic receptor (β2AR), which is one of the best-studied family A G-protein-coupled receptors. This is due to the lack of methods for easy and precise detection of the oligomeric state of membrane proteins on living cells. Here, we show that a combination of the coiled-coil tag-probe labeling method and spectral imaging enable a stoichiometric analysis of the oligomeric state of membrane proteins on living cells using monomeric, dimeric, and tetrameric standard membrane proteins. Using this method, we found that β2ARs do not form constitutive homooligomers, while they exhibit their functions such as the cyclic adenosine 5'-monophosphate (cAMP) signaling and internalization upon agonist stimulation.
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Affiliation(s)
- Kenichi Kawano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
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17
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Valentin-Hansen L, Groenen M, Nygaard R, Frimurer TM, Holliday ND, Schwartz TW. The arginine of the DRY motif in transmembrane segment III functions as a balancing micro-switch in the activation of the β2-adrenergic receptor. J Biol Chem 2012; 287:31973-82. [PMID: 22843684 DOI: 10.1074/jbc.m112.348565] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Recent high resolution x-ray structures of the β2-adrenergic receptor confirmed a close salt-bridge interaction between the suspected micro-switch residue ArgIII:26 (Arg3.50) and the neighboring AspIII:25 (Asp3.49). However, neither the expected "ionic lock" interactions between ArgIII:26 and GluVI:-06 (Glu6.30) in the inactive conformation nor the interaction with TyrV:24 (Tyr5.58) in the active conformation were observed in the x-ray structures. Here we find through molecular dynamics simulations, after removal of the stabilizing T4 lysozyme, that the expected salt bridge between ArgIII:26 and GluVI:-06 does form relatively easily in the inactive receptor conformation. Moreover, mutational analysis of GluVI:-06 in TM-VI and the neighboring AspIII:25 in TM-III demonstrated that these two residues do function as locks for the inactive receptor conformation as we observed increased G(s) signaling, arrestin mobilization, and internalization upon alanine substitutions. Conversely, TyrV:24 appears to play a role in stabilizing the active receptor conformation as loss of function of G(s) signaling, arrestin mobilization, and receptor internalization was observed upon alanine substitution of TyrV:24. The loss of function of the TyrV:24 mutant could partly be rescued by alanine substitution of either AspIII:25 or GluVI:-06 in the double mutants. Surprisingly, removal of the side chain of the ArgIII:26 micro-switch itself had no effect on G(s) signaling and internalization and only reduced arrestin mobilization slightly. It is suggested that ArgIII:26 is equally important for stabilizing the inactive and the active conformation through interaction with key residues in TM-III, -V, and -VI, but that the ArgIII:26 micro-switch residue itself apparently is not essential for the actual G protein activation.
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Affiliation(s)
- Louise Valentin-Hansen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, the Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
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18
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Couturier C, Deprez B. Setting Up a Bioluminescence Resonance Energy Transfer High throughput Screening Assay to Search for Protein/Protein Interaction Inhibitors in Mammalian Cells. Front Endocrinol (Lausanne) 2012; 3:100. [PMID: 22973258 PMCID: PMC3438444 DOI: 10.3389/fendo.2012.00100] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 07/31/2012] [Indexed: 12/14/2022] Open
Abstract
Each step of the cell life and its response or adaptation to its environment are mediated by a network of protein/protein interactions termed "interactome." Our knowledge of this network keeps growing due to the development of sensitive techniques devoted to study these interactions. The bioluminescence resonance energy transfer (BRET) technique was primarily developed to allow the dynamic monitoring of protein/protein interactions (PPI) in living cells, and has widely been used to study receptor activation by intra- or extra-molecular conformational changes within receptors and activated complexes in mammal cells. Some interactions are described as crucial in human pathological processes, and a new class of drugs targeting them has recently emerged. The BRET method is well suited to identify inhibitors of PPI and here is described why and how to set up and optimize a high throughput screening assay based on BRET to search for such inhibitory compounds. The different parameters to take into account when developing such BRET assays in mammal cells are reviewed to give general guidelines: considerations on the targeted interaction, choice of BRET version, inducibility of the interaction, kinetic of the monitored interaction, and of the BRET reading, influence of substrate concentration, number of cells and medium composition used on the Z' factor, and expected interferences from colored or fluorescent compounds.
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Affiliation(s)
- Cyril Couturier
- Univ Lille Nord de FranceLille, France
- INSERM U761, Biostructures and Drug DiscoveryLille, France
- Université du Droit et de la Santé de LilleLille, France
- Institut Pasteur LilleLille, France
- Pôle de Recherche Interdisciplinaire sur le MédicamentLille, France
- *Correspondence: Cyril Couturier, UMR 761, Biostructure and Drug Discovery, Institut Pasteur de Lille, Université Lille 2, 1 rue du Pr Calmette, 59000 Lille, France. e-mail:
| | - Benoit Deprez
- Univ Lille Nord de FranceLille, France
- INSERM U761, Biostructures and Drug DiscoveryLille, France
- Université du Droit et de la Santé de LilleLille, France
- Institut Pasteur LilleLille, France
- Pôle de Recherche Interdisciplinaire sur le MédicamentLille, France
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19
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Provasi D, Artacho MC, Negri A, Mobarec JC, Filizola M. Ligand-induced modulation of the free-energy landscape of G protein-coupled receptors explored by adaptive biasing techniques. PLoS Comput Biol 2011; 7:e1002193. [PMID: 22022248 PMCID: PMC3192824 DOI: 10.1371/journal.pcbi.1002193] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 07/27/2011] [Indexed: 01/14/2023] Open
Abstract
Extensive experimental information supports the formation of ligand-specific conformations of G protein-coupled receptors (GPCRs) as a possible molecular basis for their functional selectivity for signaling pathways. Taking advantage of the recently published inactive and active crystal structures of GPCRs, we have implemented an all-atom computational strategy that combines different adaptive biasing techniques to identify ligand-specific conformations along pre-determined activation pathways. Using the prototypic GPCR β2-adrenergic receptor as a suitable test case for validation, we show that ligands with different efficacies (either inverse agonists, neutral antagonists, or agonists) modulate the free-energy landscape of the receptor by shifting the conformational equilibrium towards active or inactive conformations depending on their elicited physiological response. Notably, we provide for the first time a quantitative description of the thermodynamics of the receptor in an explicit atomistic environment, which accounts for the receptor basal activity and the stabilization of different active-like states by differently potent agonists. Structural inspection of these metastable states reveals unique conformations of the receptor that may have been difficult to retrieve experimentally.
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Affiliation(s)
- Davide Provasi
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Marta Camacho Artacho
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Ana Negri
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Juan Carlos Mobarec
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Marta Filizola
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York, United States of America
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20
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Pétrin D, Hébert TE. Imaging-based approaches to understanding g protein-coupled receptor signalling complexes. Methods Mol Biol 2011; 756:37-60. [PMID: 21870219 DOI: 10.1007/978-1-61779-160-4_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the last 10 years, imaging assays based on resonance energy transfer (RET) and protein fragment complementation have made it possible to study interactions between components of G protein-coupled receptor (GPCR) signalling complexes in living cells under physiological conditions. Here, we consider the history of such approaches, the current tools available and how they have changed our understanding of GPCR signalling. We also discuss some theoretical and methodological issues important when combining the different types of assay.
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Affiliation(s)
- Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
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21
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De los Frailes M, Diez E. Screening technologies for G protein-coupled receptors: from HTS to uHTS. Methods Mol Biol 2009; 552:15-37. [PMID: 19513639 DOI: 10.1007/978-1-60327-317-6_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The discovery of drugs for G protein-coupled receptors (GPCRs) has traditionally been very successful, even before the structural nature of these molecular targets was elucidated. Over the years, this family of proteins has become more important in the understanding and treatment of different human pathologies, representing today close to 30% of the molecular targets of all marketed drugs. The sequencing of the human genome unveiled the existence of many new GPCRs and this has increased even more the interest of this family of proteins as potential drug targets. Today the search for compounds that interfere or modulate the function of GPCRs is one of the major focuses of pharmaceutical companies. The understanding of the molecular events that take place upon receptor activation, together with the need of testing large chemical libraries, has resulted in the development of a variety of methods and technologies to measure the activity of these receptors. In this chapter we will review most of the assay technologies currently in use for "in vitro" pharmacological screening, their evolution, their capabilities, and their limitations.
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Affiliation(s)
- Maite De los Frailes
- Department of Screening and Compound Profiling, Molecular Discovery Research, GlaxoSmithKline, Madrid, Spain
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22
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Bacart J, Corbel C, Jockers R, Bach S, Couturier C. The BRET technology and its application to screening assays. Biotechnol J 2008; 3:311-24. [DOI: 10.1002/biot.200700222] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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Eglen RM, Reisine T, Roby P, Rouleau N, Illy C, Bossé R, Bielefeld M. The use of AlphaScreen technology in HTS: current status. CURRENT CHEMICAL GENOMICS 2008; 1:2-10. [PMID: 20161822 PMCID: PMC2775125 DOI: 10.2174/1875397300801010002] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 01/13/2008] [Accepted: 01/19/2008] [Indexed: 11/22/2022]
Abstract
AlphaScreen (Amplified Luminescent Proximity Homogeneous Assay Screen) is versatile assay technology developed to measuring analytes using a homogenous protocol. This technology is an example of a bead-based proximity assay and was developed from a diagnostic assay technology known as LOCI (Luminescent Oxygen Channeling Assay). Here, singlet oxygen molecules, generated by high energy irradiation of Donor beads, travel over a constrained distance (approx. 200 nm) to Acceptor beads. This results in excitation of a cascading series of chemical reactions, ultimately causing generation of a chemiluminescent signal.In the past decade, a wide variety of applications has been reported, ranging from detection of analytes involved in cell signaling, including protein:protein, protein:peptide, protein:small molecule or peptide:peptide interactions. Numerous homogeneous HTS-optimized assays have been reported using the approach, including generation of second messengers (such as accumulation of cyclic AMP, cyclic GMP, inositol [1, 4, 5] trisphosphate or phosphorylated ERK) from liganded GPCRs or tyrosine kinase receptors, post-translational modification of proteins (such as proteolytic cleavage, phosphorylation, ubiquination and sumoylation) as well as protein-protein and protein-nucleic acid interactions.Recently, the basic AlphaScreen technology was extended in that the chemistry of the Acceptor bead was modified such that emitted light is more intense and spectrally defined, thereby markedly reducing interference from biological fluid matrices (such as trace hemolysis in serum and plasma). In this format, referred to as AlphaLISA, it provides an alternative technology to classical ELISA assays and is suitable for high throughput automated fluid dispensing and detection systems.Collectively, AlphaScreen and AlphaLISA technologies provide a facile assay platform with which one can quantitate complex cellular processes using simple no-wash microtiter plate based assays. They provide the means by which large compound libraries can be screened in a high throughput fashion at a diverse range of therapeutically important targets, often not readily undertaken using other homogeneous assay technologies. This review assesses the current status of the technology in drug discovery, in general, and high throughput screening (HTS), in particular.
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Affiliation(s)
- Richard M Eglen
- President, Molecular Medicine, PerkinElmer Life and Analytical Sciences, 940 Winter St., Waltham, MA 02451-1457, USA.
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24
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Verkaar F, van Rosmalen JWG, Blomenröhr M, van Koppen CJ, Blankesteijn WM, Smits JFM, Zaman GJR. G protein-independent cell-based assays for drug discovery on seven-transmembrane receptors. BIOTECHNOLOGY ANNUAL REVIEW 2008; 14:253-74. [PMID: 18606367 DOI: 10.1016/s1387-2656(08)00010-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Conventional cell-based assays for seven-transmembrane receptors, also known as G protein-coupled receptors, rely on the coupling of the ligand-bound receptor to heterotrimeric G proteins. New assay methods have become available that are not based on G protein activation, but that apply the molecular mechanism underlying the attenuation of G protein signaling mediated by beta-arrestin. beta-arrestin is a cytoplasmic protein that targets receptors to clathrin-coated endocytotic vesicles for degradation or recycling. This process has been visualized and quantified in high-content imaging assays using receptor- or beta-arrestin-chimeras with green fluorescent protein. Other assay methods use bioluminescence resonance energy transfer, enzyme fragment complementation, or a protease-activated transcriptional reporter gene, to measure receptor-beta-arrestin proximity. beta-arrestin recruitment assays have been applied successfully for receptors coupling to Galpha(q), Galpha(s) and Galpha(i) proteins, thus providing a generic assay platform for drug discovery on G protein-coupled receptors. The best understood signal transduction pathway elicited by the seven-transmembrane Frizzled receptors does not involve G proteins. The activation of Frizzleds by their cognate ligands of the Wnt family recruits the phosphoprotein dishevelled. Dishevelled regulates a protein complex involved in the destruction of beta-catenin. Activation of Frizzled blocks degradation of beta-catenin, which translocates to the nucleus to activate transcription of Wnt-responsive genes. The cytoplasm-to-nuclear translocation of beta-catenin forms the basis of several high-content assays to measure Wnt/Frizzled signal transduction. Interestingly, Frizzled receptors have recently been shown to internalize and to recruit beta-arrestin. This suggests that beta-arrestin recruitment assays may be applied for drug discovery on seven-transmembrane receptors beyond G protein-coupled receptors.
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Affiliation(s)
- Folkert Verkaar
- Molecular Pharmacology Unit, Organon BioSciences, Oss, The Netherlands
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25
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Eglen RM. Assessing GPCR activation using protein complementation: a novel technique for HTS. Biochem Soc Trans 2007; 35:746-8. [PMID: 17635139 DOI: 10.1042/bst0350746] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
GPCRs (G-protein-coupled receptors) are critical targets in drug discovery. Although most HTS (high-throughput screening) assays are routinely used to identify functional agonism or antagonism, they are suboptimal as methods to screen for modulators of other, novel, aspects of GPCR function. Indeed, it is now evident that GPCRs are highly complex proteins that interact with RAMPs (receptor-activity-modifying partners), β-arrestins, G-proteins, as well as functioning in potential homo- or hetero-meric complexes. Consequently, novel HTS technologies are now required that would facilitate interrogation of GPCRs in terms of their cellular protein–protein interactions. One approach is oligomerization-assisted complementation of monomeric protein fragments and detection of fragment reassembly. Notably, the use of enzymes has advantages in this regard, since complementation results in catalytically competent protein. The assay signal generated in this fashion results in assays of high sensitivity, thereby enabling protocols to be developed in HTS systems that require extremely low fluid volumes. The use of complementing proteins that generate a luminescent signal also provides assays that are markedly free from artefactual interferences.
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Affiliation(s)
- R M Eglen
- Discovery and Research Reagents, PerkinElmer Life and Analytical Sciences, 940 Winter Street, Waltham, MA 02451-1457, USA.
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