1
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Varas N, Grabowski R, Jarosinski MA, Tai N, Herzog RI, Ismail-Beigi F, Yang Y, Cherrington AD, Weiss MA. Ultra-stable insulin-glucagon fusion protein exploits an endogenous hepatic switch to mitigate hypoglycemic risk. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.594997. [PMID: 38826486 PMCID: PMC11142066 DOI: 10.1101/2024.05.20.594997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The risk of hypoglycemia and its serious medical sequelae restrict insulin replacement therapy for diabetes mellitus. Such adverse clinical impact has motivated development of diverse glucose-responsive technologies, including algorithm-controlled insulin pumps linked to continuous glucose monitors ("closed-loop systems") and glucose-sensing ("smart") insulins. These technologies seek to optimize glycemic control while minimizing hypoglycemic risk. Here, we describe an alternative approach that exploits an endogenous glucose-dependent switch in hepatic physiology: preferential insulin signaling (under hyperglycemic conditions) versus preferential counter-regulatory glucagon signaling (during hypoglycemia). Motivated by prior reports of glucagon-insulin co-infusion, we designed and tested an ultra-stable glucagon-insulin fusion protein whose relative hormonal activities were calibrated by respective modifications; physical stability was concurrently augmented to facilitate formulation, enhance shelf life and expand access. An N-terminal glucagon moiety was stabilized by an α-helix-compatible Lys 13 -Glu 17 lactam bridge; A C-terminal insulin moiety was stabilized as a single chain with foreshortened C domain. Studies in vitro demonstrated (a) resistance to fibrillation on prolonged agitation at 37 °C and (b) dual hormonal signaling activities with appropriate balance. Glucodynamic responses were monitored in rats relative to control fusion proteins lacking one or the other hormonal activity, and continuous intravenous infusion emulated basal subcutaneous therapy. Whereas efficacy in mitigating hyperglycemia was unaffected by the glucagon moiety, the fusion protein enhanced endogenous glucose production under hypoglycemic conditions. Together, these findings provide proof of principle toward a basal glucose-responsive insulin biotechnology of striking simplicity. The fusion protein's augmented stability promises to circumvent the costly cold chain presently constraining global insulin access. Significance Statement The therapeutic goal of insulin replacement therapy in diabetes is normalization of blood-glucose concentration, which prevents or delays long-term complications. A critical barrier is posed by recurrent hypoglycemic events that results in short- and long-term morbidities. An innovative approach envisions co-injection of glucagon (a counter-regulatory hormone) to exploit a glycemia-dependent hepatic switch in relative hormone responsiveness. To provide an enabling technology, we describe an ultra-stable fusion protein containing insulin- and glucagon moieties. Proof of principle was obtained in rats. A single-chain insulin moiety provides glycemic control whereas a lactam-stabilized glucagon extension mitigates hypoglycemia. This dual-hormone fusion protein promises to provide a basal formulation with reduced risk of hypoglycemia. Resistance to fibrillation may circumvent the cold chain required for global access.
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2
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Chen CY, Elmore S, Lalami I, Neal H, Vadlamudi RK, Raj GV, Ahn JM. Oligo-benzamide-based peptide mimicking tools for modulating biology. Methods Enzymol 2024; 698:221-245. [PMID: 38886033 DOI: 10.1016/bs.mie.2024.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The oligo-benzamide scaffold is a rigid organic framework that can hold 2-3 functional groups as O-alkyl substituents on its benzamide units, mirroring their natural arrangement in an α-helix. Oligo-benzamides demonstrated outstanding α-helix mimicry and can be readily synthesized by following high yielding and iterative reaction steps in both solution-phase and solid-phase. A number of oligo-benzamides have been designed to emulate α-helical peptide segments in biologically active proteins and showed strong protein binding, in turn effectively disrupting protein-protein interactions in vitro and in vivo. In this chapter, the design of oligo-benzamides for mimicking α-helices, efficient synthetic routes for producing them, and their biomedical studies showing remarkable potency in inhibiting protein functions are discussed.
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Affiliation(s)
- Chia-Yuan Chen
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, United States
| | - Scott Elmore
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, United States
| | - Ismail Lalami
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, United States
| | - Henry Neal
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, United States
| | - Ratna K Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Ganesh V Raj
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jung-Mo Ahn
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, United States.
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3
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A Structure-Activity Relationship Study of Bis-Benzamides as Inhibitors of Androgen Receptor-Coactivator Interaction. Molecules 2019; 24:molecules24152783. [PMID: 31370197 PMCID: PMC6696232 DOI: 10.3390/molecules24152783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 02/05/2023] Open
Abstract
The interaction between androgen receptor (AR) and coactivator proteins plays a critical role in AR-mediated prostate cancer (PCa) cell growth, thus its inhibition is emerging as a promising strategy for PCa treatment. To develop potent inhibitors of the AR-coactivator interaction, we have designed and synthesized a series of bis-benzamides by modifying functional groups at the N/C-terminus and side chains. A structure-activity relationship study showed that the nitro group at the N-terminus of the bis-benzamide is essential for its biological activity while the C-terminus can have either a methyl ester or a primary carboxamide. Surveying the side chains with various alkyl groups led to the identification of a potent compound 14d that exhibited antiproliferative activity (IC50 value of 16 nM) on PCa cells. In addition, biochemical studies showed that 14d exerts its anticancer activity by inhibiting the AR-PELP1 interaction and AR transactivation.
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4
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Henninot A, Collins JC, Nuss JM. The Current State of Peptide Drug Discovery: Back to the Future? J Med Chem 2017; 61:1382-1414. [PMID: 28737935 DOI: 10.1021/acs.jmedchem.7b00318] [Citation(s) in RCA: 648] [Impact Index Per Article: 92.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Over the past decade, peptide drug discovery has experienced a revival of interest and scientific momentum, as the pharmaceutical industry has come to appreciate the role that peptide therapeutics can play in addressing unmet medical needs and how this class of compounds can be an excellent complement or even preferable alternative to small molecule and biological therapeutics. In this Perspective, we give a concise description of the recent progress in peptide drug discovery in a holistic manner, highlighting enabling technological advances affecting nearly every aspect of this field: from lead discovery, to synthesis and optimization, to peptide drug delivery. An emphasis is placed on describing research efforts to overcome the inherent weaknesses of peptide drugs, in particular their poor pharmacokinetic properties, and how these efforts have been critical to the discovery, design, and subsequent development of novel therapeutics.
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Affiliation(s)
- Antoine Henninot
- Ferring Research Institute , 4245 Sorrento Valley Boulevard, San Diego, California 92121, United States
| | - James C Collins
- Ferring Research Institute , 4245 Sorrento Valley Boulevard, San Diego, California 92121, United States
| | - John M Nuss
- Ferring Research Institute , 4245 Sorrento Valley Boulevard, San Diego, California 92121, United States
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5
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Torres MDT, Silva AF, de Souza Silva L, de Sá Pinheiro AA, Oliveira VXJ. Angiotensin II restricted analogs with biological activity in the erythrocytic cycle of Plasmodium falciparum. J Pept Sci 2014; 21:24-8. [DOI: 10.1002/psc.2714] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 01/03/2023]
Affiliation(s)
| | - Adriana Farias Silva
- Centro de Ciências Naturais e Humanas; Universidade Federal do ABC; Santo André SP Brazil
| | - Leandro de Souza Silva
- Instituto de Biofísica Carlos Chagas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Ana Acácia de Sá Pinheiro
- Instituto de Biofísica Carlos Chagas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
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6
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Manandhar B, Ahn JM. Glucagon-like peptide-1 (GLP-1) analogs: recent advances, new possibilities, and therapeutic implications. J Med Chem 2014; 58:1020-37. [PMID: 25349901 PMCID: PMC4329993 DOI: 10.1021/jm500810s] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
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Glucagon-like peptide-1 (GLP-1) is
an incretin that plays important
physiological roles in glucose homeostasis. Produced from intestine
upon food intake, it stimulates insulin secretion and keeps pancreatic
β-cells healthy and proliferating. Because of these beneficial
effects, it has attracted a great deal of attention in the past decade,
and an entirely new line of diabetic therapeutics has emerged based
on the peptide. In addition to the therapeutic applications, GLP-1
analogs have demonstrated a potential in molecular imaging of pancreatic β-cells;
this may be useful in early detection of the disease and evaluation
of therapeutic interventions, including islet transplantation. In
this Perspective, we focus on GLP-1 analogs for their studies on improvement
of biological activities, enhancement of metabolic stability, investigation
of receptor interaction, and visualization of the pancreatic islets.
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Affiliation(s)
- Bikash Manandhar
- Department of Chemistry, University of Texas at Dallas , Richardson, Texas 75080, United States
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7
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Der Torossian Torres M, Silva AF, Alves FL, Capurro ML, Miranda A, Oliveira Junior VX. The Importance of Ring Size and Position for the Antiplasmodial Activity of Angiotensin II Restricted Analogs. Int J Pept Res Ther 2014. [DOI: 10.1007/s10989-014-9392-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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8
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Miller LJ, Dong M, Harikumar KG. Ligand binding and activation of the secretin receptor, a prototypic family B G protein-coupled receptor. Br J Pharmacol 2012; 166:18-26. [PMID: 21542831 DOI: 10.1111/j.1476-5381.2011.01463.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The secretin receptor is a prototypic member of family B G protein-coupled receptors that binds and responds to a linear 27-residue peptide natural ligand. The carboxyl-terminal region of this peptide assumes a helical conformation that occupies the peptide-binding cleft within the structurally complex disulphide-bonded amino-terminal domain of this receptor. The amino terminus of secretin is directed toward the core helical bundle domain of this receptor that seems to be structurally distinct from the analogous region of family A G protein-coupled receptors. This amino-terminal region of secretin is critical for its biological activity, to stimulate Gs coupling and the agonist-induced cAMP response. While the natural peptide ligand is known to span the two key receptor domains, with multiple residue-residue approximation constraints well established, the orientation of the receptor amino terminus relative to the receptor core helical bundle domain is still unclear. Fluorescence studies have established that the mid-region and carboxyl-terminal end of secretin are protected by the receptor peptide-binding cleft and the amino terminus of secretin is most exposed to the aqueous milieu as it is directed toward the receptor core, with the mid-region of the peptide becoming more exposed upon receptor activation. Like other family B peptide hormone receptors, the secretin receptor is constitutively present in a structurally specific homo-dimeric complex built around the lipid-exposed face of transmembrane segment four. This complex is important for facilitating G protein association and achieving the high affinity state of this receptor.
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Affiliation(s)
- Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA.
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9
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Dong M, Te JA, Xu X, Wang J, Pinon DI, Storjohann L, Bordner AJ, Miller LJ. Lactam constraints provide insights into the receptor-bound conformation of secretin and stabilize a receptor antagonist. Biochemistry 2011; 50:8181-92. [PMID: 21851058 DOI: 10.1021/bi2008036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The natural ligands for family B G protein-coupled receptors are moderate-length linear peptides having diffuse pharmacophores. The amino-terminal regions of these ligands are critical for biological activity, with their amino-terminal truncation leading to production of orthosteric antagonists. The carboxyl-terminal regions of these peptides are thought to occupy a ligand-binding cleft within the disulfide-bonded amino-terminal domains of these receptors, with the peptides in amphipathic helical conformations. In this work, we have characterized the binding and activity of a series of 11 truncated and lactam-constrained secretin(5-27) analogues at the prototypic member of this family, the secretin receptor. One peptide in this series with lactam connecting residues 16 and 20 [c[E(16),K(20)][Y(10)]sec(5-27)] improved the binding affinity of its unconstrained parental peptide 22-fold while retaining the absence of endogenous biological activity and competitive antagonist characteristics. Homology modeling with molecular mechanics and molecular dynamics simulations established that this constrained peptide occupies the ligand-binding cleft in an orientation similar to that of natural full-length secretin and provided insights into why this peptide was more effective than other truncated conformationally constrained peptides in the series. This lactam bridge is believed to stabilize an extended α-helical conformation of this peptide while in solution and not to interfere with critical residue-residue approximations while docked to the receptor.
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Affiliation(s)
- Maoqing Dong
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259, USA
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10
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Lee TK, Ahn JM. Solid-phase synthesis of tris-benzamides as α-helix mimetics. ACS COMBINATORIAL SCIENCE 2011; 13:107-11. [PMID: 21395339 DOI: 10.1021/co100056c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small molecules mimicking α-helices are of great interest since numerous protein-protein interactions use helical structures at the interface. With a goal of generating libraries of α-helix mimetics, an efficient solid-phase synthetic method was developed to produce tris-benzamides. The tris-benzamide scaffold was designed to place three side-chain functional groups found at the i, i + 4, and i + 7 positions of an α-helix, emulating one helical face. The synthetic strategy involves simple and iterative reactions of removal of an allyl ester, formation of an amide bond via an O → N acyl migration, and an O-alkylation. A small library of twenty tris-benzamides containing a variety of functional groups was prepared in high purity (83-99%) to demonstrate the versatility of the synthetic approach. This methodology allowed the facile and rapid construction of α-helix mimetics that would facilitate the identification of small molecules for target proteins.
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Affiliation(s)
- Tae-Kyung Lee
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Jung-Mo Ahn
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
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11
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Murage EN, Gao G, Bisello A, Ahn JM. Development of potent glucagon-like peptide-1 agonists with high enzyme stability via introduction of multiple lactam bridges. J Med Chem 2010; 53:6412-20. [PMID: 20687610 DOI: 10.1021/jm100602m] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) has the ability to lower the blood glucose level, and its regulatory functions make it an attractive therapeutic agent for the treatment of type 2 diabetes. However, its rapid degradation by enzymes like dipeptidyl peptidase-IV (DPP-IV) and neutral endopeptidase (NEP) 24.11 severely compromises its effective clinical use. Whereas specific DPP-IV inhibitors have been developed, NEP 24.11 targets multiple sites in the GLP-1 sequence, which makes it difficult to block. To address this drawback, we have designed and synthesized conformationally constrained GLP-1 analogues by introducing multiple lactam bridges that stabilized both alpha-helices in the N- and C-terminal regions simultaneously. In addition to improving the receptor activation capability (up to 5-fold) by fixing the alpha-helical conformations required for optimal receptor interaction, the introduced lactam bridges provided outstanding shielding over NEP 24.11 (half-life of >96 h). These highly constrained peptides are the first examples of NEP 24.11-resistant GLP-1 analogues.
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Affiliation(s)
- Eunice N Murage
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080,USA
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12
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Natalini B, Sardella R, Giacchè N, Palmiotto S, Camaioni E, Marinozzi M, Macchiarulo A, Pellicciari R. Chiral ligand-exchange separation and resolution of extremely rigid glutamate analogs: 1-aminospiro[2.2]pentyl-1,4-dicarboxylic acids. Anal Bioanal Chem 2010; 397:1997-2011. [DOI: 10.1007/s00216-010-3669-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/17/2010] [Accepted: 03/21/2010] [Indexed: 11/30/2022]
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13
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Seeking for α-Helical Propensity in a Receptor-Bound Conformation of Glucagon-Like Peptide-1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 611:289-90. [DOI: 10.1007/978-0-387-73657-0_129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Murage EN, Schroeder JC, Beinborn M, Ahn JM. Search for alpha-helical propensity in the receptor-bound conformation of glucagon-like peptide-1. Bioorg Med Chem 2008; 16:10106-12. [PMID: 18952440 DOI: 10.1016/j.bmc.2008.10.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 09/30/2008] [Accepted: 10/01/2008] [Indexed: 11/27/2022]
Abstract
To elucidate the receptor-bound conformation of glucagon-like peptide-1 (GLP-1), a series of conformationally constrained GLP-1 analogues were synthesized by introducing lactam bridges between Lys(i) and Glu(i)(+4) to form alpha-helices at various positions. The activity and affinity of these analogues to GLP-1 receptors suggested that the receptor-bound conformation comprises two alpha-helical segments between residues 11-21 and 23-34. It is notable that the N-terminal alpha-helix is extended to Thr(11), and that Gly(22) plays a pivotal role in arranging the two alpha-helices. Based on these findings, a highly potent bicyclic GLP-1 analogue was synthesized which is the most conformationally constrained GLP-1 analogue reported to date.
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Affiliation(s)
- Eunice N Murage
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080, USA
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15
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Miranda LP, Winters KA, Gegg CV, Patel A, Aral J, Long J, Zhang J, Diamond S, Guido M, Stanislaus S, Ma M, Li H, Rose MJ, Poppe L, Véniant MM. Design and synthesis of conformationally constrained glucagon-like peptide-1 derivatives with increased plasma stability and prolonged in vivo activity. J Med Chem 2008; 51:2758-65. [PMID: 18412318 DOI: 10.1021/jm701522b] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A series of conformationally constrained derivatives of glucagon-like peptide-1 (GLP-1) were designed and evaluated. By use of [Gly (8)]GLP-1(7-37)-NH2 (2) peptide as a starting point, 17 cyclic derivatives possessing i to i + 4, i to i + 5, or i to i + 7 side chain to side chain lactam bridges from positions 18 to 30 were prepared. The effect of a helix-promoting alpha-amino-isobutyric acid (Aib) substitution at position 22 was also evaluated. The introduction of i to i + 4 glutamic acid-lysine lactam constraints in c[Glu (18)-Lys (22)][Gly (8)]GLP-1(7-37)-NH2 (6), c[Glu (22)-Lys (26)][Gly (8)]GLP-1(7-37)-NH2 (10), and c[Glu (23)-Lys (27)][Gly (8)]GLP-1(7-37)-NH2 (11) resulted in potent functional activity and receptor affinities comparable to native GLP-1. Selected GLP-1 peptides were chemoselectively PEGylated in order to prolong their in vivo activity. PEGylated peptides [Gly (8),Aib (22)]GLP-1(7-37)-Cys ((PEG))-Ala-NH2 (23) and c[Glu (22)-Lys (26)][Gly (8)]GLP-1(7-37)-Cys ((PEG))-Ser-Gly-NH2 (24) retained picomolar functional potency and avid receptor binding properties. Importantly, PEGylated GLP-1 peptide 23 exhibited sustained in vivo efficacy with respect to blood glucose reduction and decreased body weight for several days in nonhuman primates.
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Affiliation(s)
- Les P Miranda
- Chemistry Research and Discovery, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, California 91320, USA.
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16
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17
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Tyndall JDA, Pfeiffer B, Abbenante G, Fairlie DP. Over One Hundred Peptide-Activated G Protein-Coupled Receptors Recognize Ligands with Turn Structure. Chem Rev 2005; 105:793-826. [PMID: 15755077 DOI: 10.1021/cr040689g] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Joel D A Tyndall
- Center for Drug Design and Development, Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
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18
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Chen H, Yao X, Petitjean M, Xia H, Yao J, Panaye A, Doucet J, Fan B. Insight into the Bioactivity and Metabolism of Human Glucagon Receptor Antagonists from 3D-QSAR Analyses. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/qsar.200430884] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Leduc AM, Trent JO, Wittliff JL, Bramlett KS, Briggs SL, Chirgadze NY, Wang Y, Burris TP, Spatola AF. Helix-stabilized cyclic peptides as selective inhibitors of steroid receptor-coactivator interactions. Proc Natl Acad Sci U S A 2003; 100:11273-8. [PMID: 13679575 PMCID: PMC208747 DOI: 10.1073/pnas.1934759100] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Indexed: 11/18/2022] Open
Abstract
The interaction between nuclear receptors and coactivators provides an arena for testing whether protein-protein interactions may be inhibited by small molecule drug candidates. We provide evidence that a short cyclic peptide, containing a copy of the LXXLL nuclear receptor box pentapeptide, binds tightly and selectively to estrogen receptor alpha. Furthermore, as shown by x-ray analysis, the disulfide-bridged nonapeptide, nonhelical in aqueous solutions, is able to adopt a quasihelical conformer while binding to the groove created by ligand attachment to estrogen receptor alpha. An i, i+3 linked analog, H-Lys-cyclo(d-Cys-Ile-Leu-Cys)-Arg-Leu-Leu-Gln-NH2 (peptidomimetic estrogen receptor modulator 1), binds with a Ki of 25 nM, significantly better than an i, i+4 bridged cyclic amide, as predicted by molecular modeling design criteria. The induction of helical character, effective binding, and receptor selectivity exhibited by this peptide analog provide strong support for this strategy. The stabilization of minimalist surface motifs may prove useful for the control of other macromolecular assemblies, especially when an amphiphilic helix is crucial for the strong binding interaction between two proteins.
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Affiliation(s)
- Anne-Marie Leduc
- Department of Chemistry, University of Louisville, Louisville, KY 40292, USA
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20
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Abstract
Side-chain lactam bridges linking amino acid residues that are spaced several residues apart in the linear sequence offer a convenient and flexible method for introducing conformational constraints into a peptide structure. The availability of a variety of selectively cleavable protecting groups for amines and carboxylic acids allows for several approaches to the synthesis of monocyclic, dicyclic, and bicyclic lactam-bridged peptides by solid-phase methods. Multicyclic structures are also accessible, but segment-condensation syntheses with solution-phase cyclizations are most likely to provide the best synthetic approach to these more complex constrained peptides. Lactam bridges linking (i, i + 3)-, (i, i + 4), and (i, i + 7)-spaced residue pairs have all proven useful for stabilization of alpha helices, and (i, i + 3)-linked residues have also been demonstrated to stabilize beta-turns. These structures are finding an increasing number of applications in protein biology, including studies of protein folding, protein aggregation, peptide ligand-receptor recognition, and the development of more potent peptide therapeutics. Defining the functional roles of the amphiphilic alpha-helices in medium-sized peptide hormones, and studying helix propagation from rigid, alpha-helix initiating bicyclic peptides are among the most exciting developments currently underway in this field.
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Affiliation(s)
- John W Taylor
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
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21
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Hinke SA, Gelling R, Manhart S, Lynn F, Pederson RA, Kühn-Wache K, Rosche F, Demuth HU, Coy D, McIntosh CHS. Structure-activity relationships of glucose-dependent insulinotropic polypeptide (GIP). Biol Chem 2003; 384:403-7. [PMID: 12715891 DOI: 10.1515/bc.2003.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Six GIP(1-NH2) analogs were synthesized with modifications (de-protonation, N-methylation, reversed chirality, and substitution) at positions 1, 3, and 4 of the N-terminus, and additionally, a cyclized GIP derivative was synthesized. The relationship between altered structure to biological activity was assessed by measuring receptor binding affinity and ability to stimulate adenylyl cyclase in CHO-K1 cells transfected with the wild-type GIP receptor (wtGIPR). These structure-activity relationship studies demonstrate the importance of the GIP N-terminus and highlight structural constraints that can be introduced in GIP analogs. These analogs may be useful starting points for design of peptides with enhanced in vivo bioactivity.
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Affiliation(s)
- Simon A Hinke
- Department of Physiology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3
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Abstract
The most ubiquitous mode for controlling and modulating cellular function, intercellular communication, immune response and information-transduction pathways is through peptide-protein non-covalent interactions. Hormones, neurotransmitters, antigens, cytokines and growth factors represent key classes of such peptide ligands. These ligands might either be processed fragments of larger precursor proteins or surface segments of larger proteins. Although there are numerous exceptions, such as insulin, oxytocin and calcitonin, most ligands are not used directly as drugs, and often the most useful ligands for therapy would be analogues that act as antagonists of the native ligands. A search for systematic structure-based or ligand-based approaches to designing such ligands has been an important concern. Today, a robust strategy has been developed for the design of peptides as drugs, drug candidates and biological tools. This strategy includes structural, conformational, dynamic and topographical considerations.
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Affiliation(s)
- Victor J Hruby
- Department of Chemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, USA.
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