Structural basis for the therapeutic advantage of dual and triple agonists at the human GIP, GLP-1 or GCG receptors

Glucose homeostasis, regulated by glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon (GCG) is critical to human health. Several multi-targeting agonists at GIPR, GLP-1R or GCGR, developed to maximize metabolic benefits with reduced side-effects, are in clinical trials to treat type 2 diabetes and obesity. To elucidate the molecular mechanisms by which tirzepatide, a GIPR/GLP-1R dualagonist, and peptide 20, a GIPR/GLP-1R/GCGR triagonist, manifest their superior efficacies over monoagonist such as semaglutide, we determined cryo-electron microscopy structures of tirzepatide-bound GIPR and GLP-1R as well as peptide 20-bound GIPR, GLP-1R and GCGR The structures reveal both common and unique features for the dual and triple agonism by illustrating key interactions of clinical relevance at the atomic level. Retention of glucagon function is required to achieve such an advantage over GLP-1 monotherapy. Our findings provide valuable insights into the structural basis of functional versatility and therapeutic supremacy of tirzepatide and peptide 20.

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Predictors of Effectiveness of Glucagon-Like Peptide-1 Receptor Agonist Therapy in Patients with Type 2 Diabetes and Obesity

Journal of Diabetes Research ◽

10.1155/2019/1365162 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 5

Author(s):

Alina Yu. Babenko ◽

Daria A. Savitskaya ◽

Yulia A. Kononova ◽

Aleksandra Yu. Trofimova ◽

Anna V. Simanenkova ◽

...

Keyword(s):

Lipid Profile ◽

Response To Treatment ◽

Glucose And Lipid Metabolism ◽

Lower Baseline ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Insulinotropic Peptide ◽

Diabetes And Obesity ◽

Hba1c Levels

Rationale. It is well known that diabetes mellitus (DM) exacerbates the mechanisms underlying atherosclerosis. Currently, glucagon-like peptide-1 receptor agonists (aGLP-1) have one of the most prominent cardioprotective effects among the antidiabetic agents. However, the treatment with aGLP-1 is effective only in 50-70% of the cases. Taking into account the high cost of these medications, discovery of the predictors of optimal response to treatment is required. Purpose. To identify the predictors of the greater impact of aGLP-1 on HbA1c levels, weight reduction, and improvement in lipid profile. Methods. The study group consisted of 40 patients with type 2 DM (T2DM) and obesity who were treated with aGLP-1. The follow-up period was 24 weeks. Patients’ evaluation was conducted at baseline and after 24 weeks. In addition, it included the assessment of the hormones involved in glucose and lipid metabolism and appetite regulation. Results. Patients who have initially higher BMI (body mass index), glycemia, and triglycerides (TG) had better improvement in these parameters undergoing aGLP-1 treatment. In patients with a BMI loss≥5%, GLP-1 and fasting ghrelin levels were higher and ghrelin level in postnutritional status was lower. The HbA1c levels decreased more intensively in participants with higher GLP-1 levels. TG responders had lower baseline fasting glucose-dependent insulinotropic peptide (GIP) and postprandial ghrelin levels. Conclusion. The evaluation of the glycemic control, lipid profile, and GLP-1, GIP, and ghrelin levels are useable for estimating the expected efficacy of aGLP-1.

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Structure and dynamics of semaglutide and taspoglutide bound GLP-1R-Gs complexes

10.1101/2021.01.12.426449 ◽

2021 ◽

Author(s):

Xin Zhang ◽

Matthew J. Belousoff ◽

Yi-Lynn Liang ◽

Radostin Danev ◽

Patrick M. Sexton ◽

...

Keyword(s):

Structural Information ◽

Protein Complexes ◽

Binding Modes ◽

Cryo Electron Microscopy ◽

High Incidence ◽

Molecular Determinants ◽

Gs Protein ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Diabetes And Obesity

SUMMARYThe glucagon-like peptide-1 receptor (GLP-1R) regulates insulin secretion, carbohydrate metabolism and appetite, and is an important target for treatment of type II diabetes and obesity. Multiple GLP-1R agonists have entered into clinical trials, such as semaglutide, progressing to approval. Others, including taspoglutide, failed through high incidence of side-effects or insufficient efficacy. GLP-1R agonists have a broad spectrum of signalling profiles. However, molecular understanding is limited by a lack of structural information on how different GLP-1R agonists engage with the GLP-1R. In this study, we determined cryo-electron microscopy (cryo-EM) structures of GLP-1R-Gs protein complexes bound with semaglutide and taspoglutide. These revealed similar peptide binding modes to that previously observed for GLP-1. However, 3D variability analysis of the cryo-EM micrographs revealed different motions within the bound peptides and the receptor relative to when GLP-1 is bound. This work provides novel insights into the molecular determinants of peptide engagement with the GLP-1R.

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Molecular insights into ago-allosteric modulation of the human glucagon-like peptide-1 receptor

Nature Communications ◽

10.1038/s41467-021-24058-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhaotong Cong ◽

Li-Nan Chen ◽

Honglei Ma ◽

Qingtong Zhou ◽

Xinyu Zou ◽

...

Keyword(s):

Drug Target ◽

Metabolic Disorders ◽

Allosteric Modulation ◽

Structural Basis ◽

Allosteric Modulators ◽

Cryo Electron Microscopy ◽

Covalently Bonded ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Orthosteric Ligands

AbstractThe glucagon-like peptide-1 (GLP-1) receptor is a validated drug target for metabolic disorders. Ago-allosteric modulators are capable of acting both as agonists on their own and as efficacy enhancers of orthosteric ligands. However, the molecular details of ago-allosterism remain elusive. Here, we report three cryo-electron microscopy structures of GLP-1R bound to (i) compound 2 (an ago-allosteric modulator); (ii) compound 2 and GLP-1; and (iii) compound 2 and LY3502970 (a small molecule agonist), all in complex with heterotrimeric Gs. The structures reveal that compound 2 is covalently bonded to C347 at the cytoplasmic end of TM6 and triggers its outward movement in cooperation with the ECD whose N terminus penetrates into the GLP-1 binding site. This allows compound 2 to execute positive allosteric modulation through enhancement of both agonist binding and G protein coupling. Our findings offer insights into the structural basis of ago-allosterism at GLP-1R and may aid the design of better therapeutics.

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Physiology and Emerging Biochemistry of the Glucagon-Like Peptide-1 Receptor

Experimental Diabetes Research ◽

10.1155/2012/470851 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 36

Author(s):

Francis S. Willard ◽

Kyle W. Sloop

Keyword(s):

Molecular Mechanisms ◽

Three Dimensional ◽

Receptor Occupancy ◽

Allosteric Modulators ◽

Three Dimensional Modeling ◽

Dimensional Modeling ◽

Signaling Mechanisms ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1

The glucagon-like peptide-1 (GLP-1) receptor is one of the best validated therapeutic targets for the treatment of type 2 diabetes mellitus (T2DM). Over several years, the accumulation of basic, translational, and clinical research helped define the physiologic roles of GLP-1 and its receptor in regulating glucose homeostasis and energy metabolism. These efforts provided much of the foundation for pharmaceutical development of the GLP-1 receptor peptide agonists, exenatide and liraglutide, as novel medicines for patients suffering from T2DM. Now, much attention is focused on better understanding the molecular mechanisms involved in ligand induced signaling of the GLP-1 receptor. For example, advancements in biophysical and structural biology techniques are being applied in attempts to more precisely determine ligand binding and receptor occupancy characteristics at the atomic level. These efforts should better inform three-dimensional modeling of the GLP-1 receptor that will help inspire more rational approaches to identify and optimize small molecule agonists or allosteric modulators targeting the GLP-1 receptor. This article reviews GLP-1 receptor physiology with an emphasis on GLP-1 induced signaling mechanisms in order to highlight new molecular strategies that help determine desired pharmacologic characteristics for guiding development of future nonpeptide GLP-1 receptor activators.

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Acute Effects of Metformin and Vildagliptin after a Lipid-Rich Meal on Postprandial Microvascular Reactivity in Patients with Type 2 Diabetes and Obesity: A Randomized Trial

Journal of Clinical Medicine ◽

10.3390/jcm9103228 ◽

2020 ◽

Vol 9 (10) ◽

pp. 3228

Author(s):

Alessandra Schiappacassa ◽

Priscila A. Maranhão ◽

Maria das Graças Coelho de Souza ◽

Diogo G. Panazzolo ◽

José Firmino Nogueira Neto ◽

...

Keyword(s):

Type 2 Diabetes ◽

Metabolic Profile ◽

Mechanisms Of Action ◽

Plasma Viscosity ◽

Microvascular Reactivity ◽

Gastrointestinal Peptides ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Diabetes And Obesity

Background: Type 2 diabetes mellitus and obesity are both related to endothelial dysfunction. Postprandial lipemia is a cardiovascular risk. Notably, it is known that a high-fat diet may elicit microvascular dysfunction, even in healthy subjects. Since anti-diabetic drugs have different mechanisms of action and also distinct vascular benefits, we aimed to compare the results of two anti-diabetic drugs after the intake of a lipid-rich meal on microcirculation in patients with type 2 diabetes and obesity. In parallel, we also investigated the metabolic profile, oxidative stress, inflammation, plasma viscosity, and some gastrointestinal peptides. Subjects/Methods: We included 38 drug-naïve patients, all women aged between 19 and 50 years, with BMI ≥ 30 kg/m2. We performed endothelial measurements and collected samples before (fasting) and after the intake of a lipid-rich meal at 30, 60, 120, and 180 min. Patients were randomized to metformin or vildagliptin, given orally just before the meal. Endothelial function was assessed by videocapillaroscopy and laser-Doppler flowmetry to investigate microvascular reactivity. Besides, we also investigated plasma viscosity, inflammatory and oxidative stress biomarkers, gastrointestinal peptides, and metabolic profile in all time points. Results: No differences at baseline were noted between groups. Vildagliptin increased glucagon-like peptide-1 compared to metformin. Paired comparisons showed that, during the postprandial period, vildagliptin significantly changed levels of insulin and glucagon-like peptide-1, and also the dipeptidyl peptidase-4 activity, while metformin had effects on plasma glucose solely. Metformin use during the test meal promoted an increase in functional capillary density, while vildagliptin kept non-nutritive microvascular blood flow and vasomotion unchanged. Conclusions: After the intake of a lipid-rich meal, the use of vildagliptin preserved postprandial non-nutritive microflow and vasomotion, while metformin increased capillary recruitment, suggesting protective and different mechanisms of action on microcirculation.

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Characterization of glucagon-like peptide-1 receptor-binding determinants

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0250321 ◽

2000 ◽

Vol 25 (3) ◽

pp. 321-335 ◽

Cited By ~ 46

Author(s):

Q Xiao ◽

W Jeng ◽

MB Wheeler

Keyword(s):

Molecular Mechanisms ◽

Physical Interaction ◽

High Affinity Receptor ◽

Affinity Receptor ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Tm Domain ◽

Binding Determinants

Glucagon-like peptide 1 (GLP-1) is a potent insulinotropic hormone currently under study as a therapeutic agent for type 2 diabetes. Since an understanding of the molecular mechanisms leading to high-affinity receptor (R) binding and activation may facilitate the development of more potent GLP-1R agonists, we have localized specific regions of GLP-1R required for binding. The purified N-terminal fragment (hereafter referred to as NT) of the GLP-1R produced in either insect (Sf9) or mammalian (COS-7) cells was shown to bind GLP-1. The physical interaction of NT with GLP-1 was first demonstrated by cross-linking ((125)I-GLP-1/NT complex band at approximately 28 kDa) and secondly by attachment to Ni(2+)-NTA beads. The GLP-1R NT protein attached to beads bound GLP-1, but with lower affinity (inhibitory concentration (IC(50)): 4.5 x 10(-7) M) than wild-type (WT) GLP-1R (IC(50): 5.2 x 10(-9)M). The low affinity of GLP-1R NT suggested that other receptor domains may contribute to GLP-1 binding. This was supported by studies using chimeric glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptors. GIP(1-151)/GLP-1R, but not GIP(1-222)/GLP-1R, exhibited specific GLP-1 binding and GLP-1-induced cAMP production, suggesting that the region encompassing transmembrane (TM) domain 1 through to TM3 was required for binding. Since it was hypothesized that certain charged or polar amino acids in this region might be involved in binding, these residues (TM2-TM3) were analyzed by substitution mutagenesis. Five mutants (K197A, D198A, K202A, D215A, R227A) displayed remarkably reduced binding affinity. These studies indicate that the NT domain of the GLP-1R is able to bind GLP-1, but charged residues concentrated at the distal TM2/extracellular loop-1 (EC1) interface (K197, D198, K202) and in EC1 (D215 and R227) probably contribute to the binding determinants of the GLP-1R.

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Diabetes and obesity. The role of agonists glucagon-like peptide-1 of in the treatment of type 2 diabetes

Diabetes Mellitus ◽

10.14341/dm9623 ◽

2018 ◽

Vol 21 (4) ◽

pp. 293-300 ◽

Cited By ~ 1

Author(s):

Nina A. Petunina ◽

Milena Е. Telnova

Keyword(s):

Type 2 Diabetes ◽

Insulin Response ◽

Diabetic Patients ◽

Incretin Effect ◽

Receptor Agonists ◽

Number Of Patients ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Diabetes And Obesity

Significant number of patients with type 2 diabetes mellitus are obese. It is known that even glucose intolerance, as well as diabetes, can lead to vascular complications. At the same time, weight loss can reduce the risk of type 2 diabetes in obese and pre-diabetic patients. According to available data, a significant decrease in the incretin effect is observed in patients with type 2 diabetes and obese individuals. Thus, a decrease in the incretin effect leads to a violation of the insulin response to the intake of carbohydrates, and, consequently, an increase in the level of glucose in the blood. It was also found that the decrease in the incretin effect in patients with type 2 diabetes can be associated with a lower secretion of glucagon-like peptide-1. The interest is represented by groups of antidiabetic drugs capable of regulating glycemia by affecting the secretion of insulin and glucagon, depending on its level. Such drugs include glucagon-like peptide-1 receptor agonists. The article shows the advantage of prolonged action in patients with type 2 diabetes and obesity of the glucagon-like peptide 1 receptor agonists (albiglutide, dulaglutide, exenatide with slow release) dosing 1 time a week.

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The influence of peptide context on signalling and trafficking of glucagon-like peptide-1 receptor biased agonists

10.1101/2020.02.24.961524 ◽

2020 ◽

Cited By ~ 1

Author(s):

Zijian Fang ◽

Shiqian Chen ◽

Philip Pickford ◽

Johannes Broichhagen ◽

David J Hodson ◽

...

Keyword(s):

Type 2 Diabetes ◽

Insulin Secretion ◽

Membrane Trafficking ◽

Cell Model ◽

Cellular Level ◽

Therapeutic Targeting ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1 ◽

Diabetes And Obesity

AbstractSignal bias and membrane trafficking have recently emerged as important considerations in the therapeutic targeting of the glucagon-like peptide-1 receptor (GLP-1R) in type 2 diabetes and obesity. In the present study, we have evaluated a peptide series with varying sequence homology between native GLP-1 and exendin-4, the archetypal ligands on which approved GLP-1R agonists are based. We find notable differences in agonist-mediated signalling, endocytosis and recycling, dependent both on the introduction of a His → Phe switch at position 1 and the specific mid-peptide helical regions and C-termini of the two agonists. These observations were linked to insulin secretion in a beta cell model and provide insights into how ligand factors influence GLP-1R function at the cellular level.Graphical abstract

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