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Pharmacological characterization of mono-, dual- and tri-peptidic agonists at GIP and GLP-1 receptors. Biochem Pharmacol 2020; 177:114001. [PMID: 32360365 DOI: 10.1016/j.bcp.2020.114001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/24/2020] [Indexed: 12/13/2022]
Abstract
Glucose-dependent insulinotropic peptide (GIP) is an incretin hormone with physiological roles in adipose tissue, the central nervous system and bone metabolism. While selective ligands for GIP receptor (GIPR) have not been advanced for disease treatment, dual and triple agonists of GIPR, in conjunction with that of glucagon-like peptide-1 (GLP-1) and glucagon receptors, are currently in clinical trials, with an expectation of enhanced efficacy beyond that of GLP-1 receptor (GLP-1R) agonist monotherapy for diabetic patients. Consequently, it is important to understand the pharmacological behavior of such drugs. In this study, we have explored signaling pathway specificity and the potential for biased agonism of mono-, dual- and tri-agonists of GIPR using human embryonic kidney 293 (HEK293) cells recombinantly expressing human GIPR or GLP-1R. Compared to GIP(1-42), the GIPR mono-agonists Pro3GIP and Lys3GIP are biased towards ERK1/2 phosphorylation (pERK1/2) relative to cAMP accumulation at GIPR, whereas the triple agonist at GLP-1R/GCGR/GIPR is biased towards pERK1/2 relative to β-arrestin2 recruitment. Moreover, the dual GIPR/GLP-1R agonist, LY3298176, is biased towards pERK1/2 relative to cAMP accumulation at both GIPR and GLP-1R compared to their respective endogenous ligands. These data reveal novel pharmacological properties of potential therapeutic agents that may impact on diversity in clinical responses.
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Gabe MBN, van der Velden WJC, Smit FX, Gasbjerg LS, Rosenkilde MM. Molecular interactions of full-length and truncated GIP peptides with the GIP receptor - A comprehensive review. Peptides 2020; 125:170224. [PMID: 31809770 DOI: 10.1016/j.peptides.2019.170224] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/17/2022]
Abstract
Enzymatic cleavage of endogenous peptides is a commonly used principle to initiate, modulate and terminate action for instance among cytokines and peptide hormones. The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and the related hormone glucagon-like peptide-2 (GLP-2) are all rapidly N-terminally truncated with severe loss of intrinsic activity. The most abundant circulating form of full length GIP(1-42) is GIP(3-42) (a dipeptidyl peptidase-4 (DPP-4) product). GIP(1-30)NH2 is another active form resulting from prohormone convertase 2 (PC2) cleavage of proGIP. Like GIP(1-42), GIP(1-30)NH2 is a substrate for DPP-4 generating GIP(3-30)NH2 which, compared to GIP(3-42), binds with higher affinity and very efficiently inhibits GIP receptor (GIPR) activity with no intrinsic activity. Here, we review the action of these four and multiple other N- and C-terminally truncated forms of GIP with an emphasis on molecular pharmacology, i.e. ligand binding, subsequent receptor activation and desensitization. Our overall conclusion is that the N-terminus is essential for receptor activation as GIP N-terminal truncation leads to decreased/lost intrinsic activity and antagonism (similar to GLP-1 and GLP-2), whereas the C-terminal extension of GIP(1-42), as compared to GLP-1, GLP-2 and glucagon (29-33 amino acids), has no apparent impact on the GIPR in vitro, but may play a role for other properties such as stability and tissue distribution. A deeper understanding of the molecular interaction of naturally occurring and designed GIP-based peptides, and their impact in vivo, may contribute to a future therapeutic targeting of the GIP system - either with agonists or with antagonists, or both.
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Affiliation(s)
- Maria Buur Nordskov Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Wijnand J C van der Velden
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Florent Xavier Smit
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Lærke Smidt Gasbjerg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Gasbjerg LS, Gabe MBN, Hartmann B, Christensen MB, Knop FK, Holst JJ, Rosenkilde MM. Glucose-dependent insulinotropic polypeptide (GIP) receptor antagonists as anti-diabetic agents. Peptides 2018; 100:173-181. [PMID: 29412817 DOI: 10.1016/j.peptides.2017.11.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 01/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is an intestinal hormone with a broad range of physiological actions. In the postprandial state, the hormone stimulates insulin secretion and during eu- and hypoglycemia, it stimulates glucagon secretion. In addition, GIP increases triacylglycerol (TAG) uptake in adipose tissue and decreases bone resorption. However, the importance of these actions in humans are not clearly understood as a specific GIP receptor (GIPR) antagonist - an essential tool to study GIP physiology - has been missing. Several different GIPR antagonists have been identified comprising both peptides, vaccines against GIP, GIP antibodies or antibodies against the GIPR. However, most of these have only been tested in rodents. In vitro, N- and C-terminally truncated GIP variants are potent and efficacious GIPR antagonists. Recently, GIP(3-30)NH2, a naturally occurring peptide, was shown to block the GIPR in humans and decrease GIP-induced insulin secretion as well as adipose tissue blood flow and TAG uptake. So far, there are no studies with a GIPR antagonist in patients with type 2 diabetes (T2D), but because the elevations in fasting plasma glucagon and paradoxical postprandial glucagon excursions, seen in patients with T2D, are aggravated by GIP, a GIPR antagonist could partly alleviate this and possibly improve the fasting and postprandial glycemia. Since the majority of patients with T2D are overweight, inhibition of GIP-induced fat deposition may be beneficial as well. Here we summarize the studies of GIPR antagonists and discuss the therapeutic potential of the GIP system in humans.
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Affiliation(s)
- Lærke Smidt Gasbjerg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
| | - Maria Buur Nordskov Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Filip Krag Knop
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Verma MK, Goel R, Nandakumar K, Nemmani KV. Effect of D-Ala 2 GIP, a stable GIP receptor agonist on MPTP-induced neuronal impairments in mice. Eur J Pharmacol 2017; 804:38-45. [DOI: 10.1016/j.ejphar.2017.03.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/21/2017] [Accepted: 03/29/2017] [Indexed: 01/30/2023]
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Heard KR, Wu W, Li Y, Zhao P, Woznica I, Lai JH, Beinborn M, Sanford DG, Dimare MT, Chiluwal AK, Peters DE, Whicher D, Sudmeier JL, Bachovchin WW. A General Method for Making Peptide Therapeutics Resistant to Serine Protease Degradation: Application to Dipeptidyl Peptidase IV Substrates. J Med Chem 2013; 56:8339-51. [DOI: 10.1021/jm400423p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Kathryn R. Heard
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Wengen Wu
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Youhua Li
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Peng Zhao
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Iwona Woznica
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Jack H. Lai
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Martin Beinborn
- Molecular Pharmacology
Research Center, Molecular Cardiology Research Institute, Tufts Medical Center, 800 Washington Street, Boston, Massachusetts 02111, United States
| | - David G. Sanford
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Matthew T. Dimare
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Amrita K. Chiluwal
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Diane E. Peters
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Danielle Whicher
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - James L. Sudmeier
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - William W. Bachovchin
- Department of Biochemistry, Tufts University Sackler School of Graduate Biomedical Sciences, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
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Yaqub T, Tikhonova IG, Lättig J, Magnan R, Laval M, Escrieut C, Boulègue C, Hewage C, Fourmy D. Identification of determinants of glucose-dependent insulinotropic polypeptide receptor that interact with N-terminal biologically active region of the natural ligand. Mol Pharmacol 2010; 77:547-58. [PMID: 20061446 DOI: 10.1124/mol.109.060111] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Glucose-dependent insulinotropic polypeptide receptor (GIPR), a member of family B of the G-protein coupled receptors, is a potential therapeutic target for which discovery of nonpeptide ligands is highly desirable. Structure-activity relationship studies indicated that the N-terminal part of glucose-dependent insulinotropic polypeptide (GIP) is crucial for biological activity. Here, we aimed at identification of residues in the GIPR involved in functional interaction with N-terminal moiety of GIP. A homology model of the transmembrane core of GIPR was constructed, whereas a three-dimensional model of the complex formed between GIP and the N-terminal extracellular domain of GIPR was taken from the crystal structure. The latter complex was docked to the transmembrane domains of GIPR, allowing in silico identification of putative residues of the agonist binding/activation site. All mutants were expressed at the surface of human embryonic kidney 293 cells as indicated by flow cytometry and confocal microscopy analysis of fluorescent GIP binding. Mutation of residues Arg183, Arg190, Arg300, and Phe357 caused shifts of 76-, 71-, 42-, and 16-fold in the potency to induce cAMP formation, respectively. Further characterization of these mutants, including tests with alanine-substituted GIP analogs, were in agreement with interaction of Glu3 in GIP with Arg183 in GIPR. Furthermore, they strongly supported a binding mode of GIP to GIPR in which the N-terminal moiety of GIP was sited within transmembrane helices (TMH) 2, 3, 5, and 6 with biologically crucial Tyr1 interacting with Gln224 (TMH3), Arg300 (TMH5), and Phe357 (TMH6). These data represent an important step toward understanding activation of GIPR by GIP, which should facilitate the rational design of therapeutic agents.
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Affiliation(s)
- Tahir Yaqub
- Institut National de la Santé et de la Recherche Médicale, U858, Université Paul Sabatier (Toulouse III), Toulouse Cedex 4, France
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Mentlein R. Mechanisms underlying the rapid degradation and elimination of the incretin hormones GLP-1 and GIP. Best Pract Res Clin Endocrinol Metab 2009; 23:443-52. [PMID: 19748062 DOI: 10.1016/j.beem.2009.03.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP, gastric inhibitory peptide) are secreted from intestinal L and K cells and stimulate insulin secretion from pancreatic beta cells. However, they are immediately inactivated mainly via N-terminal degradation by dipeptidyl peptidase IV (DPP IV, CD26), a specialised enzyme located on the cell surface enzyme of endothelial, epithelial and some other cell types. Cleavage by neprilysin (neutral endopeptidase) is a minor degradation route, and renal clearance eliminates incretin/fragments, but appears of less importance for regulating incretin bioactivities. Based on these observations two novel types of drugs for the treatment of type 2 diabetes have been developed: DPP IV inhibitors and DPP IV-resistant incretin analogues. Both have distinct advantages and disadvantages. Potential side effects of DPP IV inhibitors may result from affecting the bioactivity of other hormones, neuropeptides or chemokines and also by their cross-reactivity with DPP IV-related enzymes.
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Affiliation(s)
- Rolf Mentlein
- Department of Anatomy, University of Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
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Functional expression of glucose-dependent insulinotropic polypeptide receptors is coupled to differentiation in a human adipocyte model. Int J Obes (Lond) 2008; 32:1705-11. [PMID: 18779825 DOI: 10.1038/ijo.2008.148] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To establish that human adipocytes express functional glucose-dependent insulinotropic peptide (GIP) receptors and in particular the regulation of GIP receptor (GIPR) expression in the context of the dynamic process of adipocyte differentiation. DESIGN A combination of semiquantitative real-time PCR and measurement of GIP-stimulated cAMP accumulation was used to establish the expression and functional coupling of GIPRs during in vitro differentiation of human Simpson-Golabi-Behmel syndrome (SGBS) preadipocytes. RESULTS Semiquantitative real-time PCR revealed that GIPR expression was substantially increased by day 4 of differentiation, reaching a maximum around 6-8 days (approximately 200-fold increase above undifferentiated cells, n=2). We also analysed the expression of the adipocyte fatty acid binding protein (FABP4) to relate GIPR expression to a molecular differentiation marker of adipogenesis. FABP4 expression was barely detectable in undifferentiated cells. However, following exposure to adipogenic medium, FABP4 expression gradually increased, with a maximal expression level around 10 days (approximately 1,600,000-fold increase above undifferentiated cells, n=2). Thus, the increases in GIPR mRNA during adipogenesis occur earlier than FABP4, suggesting that it might represent a gene expressed early in terminal differentiation and thus plays a role in fat droplet formation. A unit of 1 microM GIP failed to raise intracellular cAMP levels above basal levels in undifferentiated cells (n=3). In stark contrast, the 9-day differentiated cells produced a robust concentration-dependent increase in cAMP accumulation following stimulation with GIP, with an EC(50) value of 2.3 nM (n=3). The maximal response represented a 9-34-fold increase in cAMP accumulation above basal levels. CONCLUSIONS This study demonstrates that GIPRs are expressed by human adipocytes, both GIPR mRNA and functional receptor expression being present in differentiated adipocytes but not in preadipocytes. Further investigation into the functional effects of GIP on differentiated SGBS cells could help towards understanding exactly how GIP regulates fat accumulation in human adipocytes.
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Abstract
The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are physiological gut peptides with insulin-releasing and extrapancreatic glucoregulatory actions. Incretin analogues/mimetics activate GLP-1 or GIP receptors whilst avoiding physiological inactivation by dipeptidyl peptidase 4 (DPP-4), and they represent one of the newest classes of antidiabetic drug. The first clinically approved GLP-1 mimetic for the treatment of type-2 diabetes is exenatide (Byetta/exendin) which is administered subcutaneously twice daily. Clinical trials of liraglutide, a GLP-1 analogue suitable for once-daily administration, are ongoing. A number of other incretin molecules are at earlier stages of development. This review discusses the various attributes of GLP-1 and GIP for diabetes treatment and summarises current clinical data. Additionally, it explores the therapeutic possibilities offered by preclinical agents, such as non-peptide GLP-1 mimetics, GLP-1/glucagon hybrid peptides, and specific GIP receptor antagonists.
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Affiliation(s)
- Brian D Green
- School of Biological Sciences, Queens University Belfast, David Keir Building, Stranmillis Road, Belfast BT6 0NJ, Northern Ireland, UK.
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