N‐terminally and C‐terminally truncated forms of glucose‐dependent insulinotropic polypeptide are high‐affinity competitive antagonists of the human GIP receptor

Hansen, Laura S.; Sparre-Ulrich, Alexander Hovard; Christensen, Mikkel B.; Knop, Filip K.; Hartmann, Bolette; Holst, Jens J.

doi:10.1111/bph.13384

Cited by 80 publications

(87 citation statements)

References 72 publications

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“…However, as other G αs ‐coupled receptors, such as class A receptors, like the adrenergic receptors do not display such bias towards G αs over arrestin recruitment, it could also reflect that G αs is the main signalling pathway during physiological control. A similar difference (3000‐6000‐fold) was observed when comparing the nanomolar binding affinity ( K D ) to the picomolar potency ( EC 50 ) in cAMP accumulation, again, a general tendency for ligands of class B GPCRs and a phenomenon that ensures receptor signalling even with very little occupancy. This suggests the presence of spare receptors, that is a surplus of receptors relative to the occupancy needed for signalling output, and could reflect the high importance of receptor signalling in human health (such as blood glucose regulation among other roles for the incretin receptors).…”

Section: Discussionsupporting

confidence: 55%

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Gabe

Velden

Gadgaard

et al. 2019

Basic Clin Pharma Tox

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In patients with type 2 diabetes mellitus (T2DM), the insulinotropic action of the GIP system is desensitized, whereas this is not the case for the GLP-1 system. This has raised an interesting discussion of whether GIP agonists or antagonists are most suitable for future treatment of T2DM together with GLP-1-based therapies.Homozygous carriers of the GIP receptor (GIPR) variant, [E354Q], display lower bone mineral density, increased bone fracture risk and slightly increased blood glucose. Here, we present an in-depth molecular pharmacological phenotyping of GIPR-[E354Q]. In silico modelling suggested similar interaction of the endogenous agonist GIP(1-42) to [E354Q] as to GIPR wt. This was supported by homologous competition binding in COS-7 cells revealing GIPR wt-like affinities of GIP(1-42) with K d values of ~2 nmol/L and wt-like agonist association rates (K on ). In contrast, the dissociation rates (K off ) were slower, resulting in 25% higher agonist residence time for GIPR-[E354Q]. Moreover, in G αs signalling (cAMP production) GIP(1-42) was ~2-fold more potent and more efficacious on GIPR-[E354Q] compared to wt with 17.5% higher basal activity. No difference from GIPR wt was found in the recruitment of β-arrestin 2, whereas the agonist-induced internalization rate was 2.1-to 2.3fold faster for [E354Q]. Together with the previously described impaired recycling of [E354Q], our findings with enhanced signalling and internalization rate possibly explained by an altered ligand-binding kinetics will lead to receptor desensitization and down-regulation. This could explain the long-term functional impairment of the GIP system in bone metabolism and blood sugar maintenance for [E354Q] carriers and may shed light on the desensitization of the insulinotropic action of GIP in patients with T2DM. K E Y W O R D SGIP receptor, GIPR-[E354Q], internalization, signalling

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Section: Discussionsupporting

confidence: 55%

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Gabe

Velden

Gadgaard

et al. 2019

Basic Clin Pharma Tox

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“…Antagonists bind to all receptor states whereas agonists bind only to the G-protein-coupled forms that are assumed to represent only a small proportion of the total receptor population (9). In cancer, GPCRs are frequently overexpressed and the superiority of antagonists was shown for the gastrin-releasing peptide receptor (11), sst2 and sst3 (8), and the glucose-dependent insulinotropic polypeptide receptor (12).…”

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confidence: 99%

Highly Increased ¹²⁵I-JR11 Antagonist Binding In Vitro Reveals Novel Indications for sst₂ Targeting in Human Cancers

et al. 2016

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There is recent in vitro and in vivo evidence that somatostatin receptor subtype 2 (sst 2 ) antagonists are better tools to target neuroendocrine tumors (NETs) than sst 2 agonists. Indeed, antagonists bind to a greater number of sst 2 sites than agonists. Whether sst 2 antagonists could be used successfully to target non-NETs, expressing low sst 2 density, is unknown. Here, we compare quantitatively 125 I-JR11 sst 2 antagonist binding in vitro with that of the sst 2 agonist 125 I-Tyr 3 -octreotide in large varieties of non-NET and NET. Methods: In vitro receptor autoradiography was performed with 125 I-JR11 and 125 I-Tyr 3 -octreotide in cancers from prostate, breast, colon, kidney, thyroid, and lymphoid tissues as well as NETs as reference. Results: In general, 125 I-JR11 binds to many more sst 2 sites than 125 I-Tyr 3 -octreotide. In 13 breast cancers, 8 had a low binding (mean density, 844 6 168 dpm/mg of tissue) with the agonist whereas 12 had a high binding (mean density, 4,447 6 1,128 dpm/mg of tissue) with the antagonist. All 12 renal cell cancers showed a low binding of sst 2 with the agonist (mean density, 348 6 49 dpm/mg of tissue) whereas all cases had a high sst 2 binding with the antagonist (mean density, 3,777 6 582 dpm/mg of tissue). One of 5 medullary thyroid cancers was positive with the agonist, whereas 5 of 5 were positive with the antagonist. In 15 nonHodgkin lymphomas, many more sst 2 sites were labeled with the antagonist than with the agonist. In 14 prostate cancers, none had sst 2 binding with the agonist and only 4 had a weak binding with the antagonist. None of 17 colon cancers showed sst 2 sites with the agonist, and only 3 cases were weakly positive with the antagonist. In the various tumor types, adjacent sst 2 -expressing tissues such as vessels, lymphocytes, nerves, mucosa, or stroma were more strongly labeled with the antagonist than with the agonist. The reference NET cases, incubated with a smaller amount of tracer, were also found to have many more sst 2 sites measured with the antagonist. Conclusion: All renal cell cancers and most breast cancers, non-Hodgkin lymphomas, and medullary thyroid cancers represent novel indications for the in vivo radiopeptide targeting of sst 2 by sst 2 antagonists, comparable to NET radiotargeting with sst 2 agonists. Somat ostatin receptors (sst) are highly overexpressed in gastroenteropancreatic and extra-gastrointestinal neuroendocrine tumors (NETs). This represents the molecular basis for sst-targeted diagnostic and therapeutic procedures in NET patients with somatostatin analogs (1-3). One main clinical application makes use of the inhibitory effects of somatostatin on NET cells, particularly on hormone secretion: long-acting somatostatin analogs, such as octreotide or lanreotide, potently inhibit tumoral hormone secretion and improve related symptoms. The second targeting approach is based on the administration of radioactive somatostatin analogs for diagnostic or therapeutic purposes. Indeed, 111 In-octreotide scintigraphy (OctreoScan; Mal...

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“…COS‐7 cells were cultured at 10% CO 2 and 37°C in Dulbecco's modified Eagles medium 1885 supplemented with 10% FBS, 2 mmol/L glutamine, 180 units/mL penicillin, and 45 g/mL streptomycin. Transient transfection of the human GLP‐1 receptor was performed using the calcium phosphate precipitation method . The transfected COS‐7 cells were seeded in 96‐well plates one day after transfection (35,000 cells/well) and the experiments carried out the following day.…”

Section: Methodsmentioning

confidence: 99%

“…Transient transfection of the human GLP-1 receptor was performed using the calcium phosphate precipitation method. (29) The transfected COS-7 cells were seeded in 96-well plates one day after transfection (35,000 cells/well) and the experiments carried out the following day. In short, the cells were washed twice with HEPES-buffered saline (HBS) buffer and incubated with HBS and 1 mmol/L 3-isobutyl-1methylxanthine (IBMX) for 30 min at 37°C.…”

Section: Blood Sample Analysismentioning

confidence: 99%

A Pilot Study Showing Acute Inhibitory Effect of GLP‐1 on the Bone Resorption Marker CTX in Humans

et al. 2019

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Bones have been suggested to be a target for glucagon‐like peptide ‐1 (GLP‐1); however, studies of the effects on human bones so far have given diverging results. We hypothesized that GLP‐1, together with glucagon‐like peptide‐2 and glucose‐dependent insulinotropic polypeptide, plays a role in the gut–bone axis. We examined the acute effect of three GLP‐1 receptor ligands [GLP‐1 (7‐36)amide, GLP‐1 (9‐36)amide, and exenatide] on markers of bone remodeling. Eight healthy, normal‐weight participants, with a mean age of 24.3 years, were studied for 4 days in a double‐blinded, randomized clinical trial. Blood was collected before and after s.c. injection of GLP‐1 (7‐36)amide (1.5 nmol/kg), GLP‐1 (9‐36)amide (1.5 nmol/kg), exenatide (2.4 nmol/subject), or saline. Plasma was analyzed for bone markers and for osteoprotegerin (OPG), PTH, and IGF‐1 levels. All ligands were tested in vitro for their cAMP‐inducing activity on the human GLP‐1 receptor. GLP‐1 (7‐36)amide decreased CTX‐levels, compared with placebo (area under the curve [AUC] ±SD 0 to 120 min = –2143 ± 1294 % × min versus –883 ± 1557 % × min; p < 0.05). No difference was observed between placebo and GLP‐1 (9‐36)amide, or between placebo and exenatide, although exenatide had a similar potency as GLP‐1 (7‐36)amide for cAMP formation in vitro (EC50 of 0.093 and 0.054 nmol/L). However, exenatide reached maximum plasma concentration at 90 min versus 15 min for GLP‐1 (7‐36)amide, and plasma CTX was significantly decreased during the second hour of the study after exenatide injections compared with placebo (AUC ±SD –463.1 ± 218 % × min and –136 ± 91 % × min; p < 0.05). There was no effect of the injections on bone formation markers (P1NP and osteocalcin) or on OPG, PTH and IGF‐1 levels. In conclusion, we show that GLP‐1 receptor agonists, but not the primary metabolite GLP‐1 (9‐36)amide, decrease bone resorption, and suggest that GLP‐1 may be part of the gut–bone axis. © 2019 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

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N‐terminally and C‐terminally truncated forms of glucose‐dependent insulinotropic polypeptide are high‐affinity competitive antagonists of the human GIP receptor

Cited by 80 publications

References 72 publications

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Highly Increased ¹²⁵I-JR11 Antagonist Binding In Vitro Reveals Novel Indications for sst₂ Targeting in Human Cancers

A Pilot Study Showing Acute Inhibitory Effect of GLP‐1 on the Bone Resorption Marker CTX in Humans

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N‐terminally and C‐terminally truncated forms of glucose‐dependent insulinotropic polypeptide are high‐affinity competitive antagonists of the human GIP receptor

Cited by 80 publications

References 72 publications

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Enhanced agonist residence time, internalization rate and signalling of the GIP receptor variant [E354Q] facilitate receptor desensitization and long‐term impairment of the GIP system

Highly Increased 125I-JR11 Antagonist Binding In Vitro Reveals Novel Indications for sst2 Targeting in Human Cancers

A Pilot Study Showing Acute Inhibitory Effect of GLP‐1 on the Bone Resorption Marker CTX in Humans

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Highly Increased ¹²⁵I-JR11 Antagonist Binding In Vitro Reveals Novel Indications for sst₂ Targeting in Human Cancers