Human GPR119 Research Articles

Molecular dynamic of omega-3 compounds as an anti-obesity agent into GPR-120 receptor

Obesity is a cause of comorbid diseases such as type 2 diabetes mellitus, dyslipidemia, hypertension which is based on low-level chronic inflammation. The GPR-120 receptor plays a role in insulin sensitization which is related to diabetes mellitus which is a comorbid obesity. Omega-3 fatty acids are believed to possess anti-inflammatory properties, hence potentially serving as a preventive measure against obesity-related comorbidities. The aim of this study is to do a stability analysis of the binding affinity between nine specific chemicals derived from omega-3 and the active site of the human GPR120 receptor using molecular dynamics simulations. Docking analysis was performed using Discovery Studio Visualizer, AutoDock Tools 1.5.6, and molecular dynamic simulation with AMBER 16. In this study, we used neurotensin 8–13 as a natural ligand to bind with the neurotensin receptor. Based on the neurotensin receptor docking results, the ΔG values for the following compounds are close to the values for neurotensin 8–13 -6.41 kcal/mol; docosahexaenoic acid -8.96 kcal/mol; eicosapentaenoic acid -7.41 kcal/mol; and heneicosapentaenoic acid -6.34 kcal/mol. Neurotensin 8–13 forms hydrogen bonds with TYR146, ARG213, and PHE344 of the neurotensin receptor, whereas docosahexaenoic acid forms hydrogen bonds with TYR146. Meanwhile, the average RMSD fluctuations for each system, namely docosahexaenoic acid, eicosapentaenoic acid, and heneicosapentaenoic acid, were 0.672, 0.437, and 0.650, respectively. The SASA of the neurotensin receptor-ligand complex showed similar fluctuations, with the average values for docosahexaenoic acid, eicosapentaenoic acid, and heneicosapentaenoic acid being 230.40, 229.89, and 230.20 nm2.

G protein–receptor kinases 5/6 are the key regulators of G protein–coupled receptor 35–arrestin interactions

Human G protein-coupled receptor 35 is regulated by agonist-mediated phosphorylation of a set of five phospho-acceptor amino acids within its C-terminal tail. Alteration of both Ser300 and Ser303 to alanine in the GPR35a isoform greatly reduces the ability of receptor agonists to promote interactions with arrestin adapter proteins. Here, we have integrated the use of cell lines genome edited to lack expression of combinations of G protein receptor kinases (GRKs), selective small molecule inhibitors of subsets of these kinases, and antisera able to specifically identify either human GPR35a or mouse GPR35 only when Ser300 and Ser303 (orce; the equivalent residues in mouse GPR35) have become phosphorylated to demonstrate that GRK5 and GRK6 cause agonist-dependent phosphorylation of these residues. Extensions of these studies demonstrated the importance of the GRK5/6-mediated phosphorylation of these amino acids for agonist-induced internalization of the receptor. Homology and predictive modeling of the interaction of human GPR35 with GRKs showed that the N terminus of GRK5 is likely to dock in the same methionine pocket on the intracellular face of GPR35 as the C terminus of the α5 helix of Gα13 and, that while this is also the case for GRK6, GRK2 and GRK3 are unable to do so effectively. These studies provide unique and wide-ranging insights into modes of regulation of GPR35, a receptor that is currently attracting considerable interest as a novel therapeutic target in diseases including ulcerative colitis.

Recent advances in GPR35 pharmacology; 5-HIAA serotonin metabolite becomes a ligand.

GPR35, an orphan receptor, has been waiting for its ligand since its cloning in 1998. Many endogenous and exogenous molecules have been suggested to act as agonists of GPR35 including kynurenic acid, zaprinast, lysophosphatidic acid, and CXCL17. However, complex and controversial responses to ligands among species have become a huge hurdle in the development of therapeutics in addition to the orphan state. Recently, a serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), is reported to be a high potency ligand for GPR35 by investigating the increased expression of GPR35 in neutrophils. In addition, a transgenic knock-in mouse line is developed, in which GPR35 was replaced with a human ortholog, making it possible not only to overcome the different selectivity of agonists among species but also to conduct therapeutic experiments on human GPR35 in mouse models. In the present article, I review the recent advances and prospective therapeutic directions in GPR35 research. Especially, I'd like to draw attention of readers to the finding of 5-HIAA as a ligand of GPR35 and lead to apply the 5-HIAA and human GPR35 knock-in mice to their research fields in a variety of pathophysiological conditions.

Aminosalicylates target GPR35, partly contributing to the prevention of DSS-induced colitis

GPR35, a class A G-protein-coupled receptor, is considered an orphan receptor; the endogenous ligand and precise physiological function of GPR35 remain obscure. GPR35 is expressed relatively highly in the gastrointestinal tract and immune cells. It plays a role in colorectal diseases like inflammatory bowel diseases (IBDs) and colon cancer. More recently, the development of GPR35 targeting anti-IBD drugs is in solid request. Nevertheless, the development process is in stagnation due to the lack of a highly potent GPR35 agonist that is also active comparably in both human and mouse orthologs. Therefore, we proposed to find compounds for GPR35 agonist development, especially for the human ortholog of GPR35. As an efficient way to pick up a safe and effective GPR35 targeting anti-IBD drug, we screened Food and Drug Administration (FDA)-approved 1850 drugs using a two-step DMR assay. Interestingly, we found aminosalicylates, first-line medicine for IBDs whose precise target remains unknown, exhibited activity on both human and mouse GPR35. Among these, pro-drug olsalazine showed the most potency on GPR35 agonism, inducing ERK phosphorylation and β-arrestin2 translocation. In dextran sodium sulfate (DSS)-induced colitis, the protective effect on disease progression and inhibitory effect on TNFα mRNA expression, NF-κB and JAK-STAT3 pathway of olsalazine are compromised in GPR35 knock-out mice. The present study identified a target for first-line medicine aminosalicylates, highlighted that uncleaved pro-drug olsalazine is effective, and provided a new concept for the design of aminosalicylic GPR35 targeting anti-IBD drug.

G Protein-Coupled Receptor GPR35 Suppresses Lipid Accumulation in Hepatocytes.

Although prevalent, nonalcoholic fatty liver disease is not currently treated effectively with medicines. Initially, using wild-type and genome-edited clones of the human hepatocyte cell line HepG2, we show that activation of the orphan G protein-coupled receptor GPR35 is both able and sufficient to block liver X-receptor-mediated lipid accumulation. Studies on hepatocytes isolated from both wild-type and GPR35 knock-out mice were consistent with a similar effect of GPR35 agonists in these cells, but because of marked differences in the pharmacology of GPR35 agonists and antagonists at the mouse and human orthologues, as well as elevated basal lipid levels in hepatocytes from the GPR35 knock-out mice, no definitive conclusion could be reached. To overcome this, we generated and characterized a transgenic knock-in mouse line in which the corresponding human GPR35 splice variant replaced the mouse orthologue. In hepatocytes from these humanized GPR35 mice, activation of this receptor was shown conclusively to prevent, and also reverse, lipid accumulation induced by liver X-receptor stimulation. These studies highlight the potential to target GPR35 in the context of fatty liver diseases.

CPL207280, a Novel G Protein-Coupled Receptor 40/Free Fatty Acid Receptor 1-Specific Agonist, Shows a Favorable Safety Profile and Exerts Antidiabetic Effects in Type 2 Diabetic Animals.

G protein-coupled receptor (GPR) 40 is a free fatty acid receptor mainly expressed in pancreatic β-cells activated by medium- and long-chain fatty acids and regulating insulin secretion via an increase in cytosolic free calcium ([Ca2+]i). Activation of GPR40 in pancreatic β-cells may improve glycemic control in type 2 diabetes through enhancement of glucose-stimulated insulin secretion. However, the most clinically advanced GPR40 agonist-TAK-875 (fasiglifam)-was withdrawn from phase III because of its hepatotoxicity resulting from the inhibition of pivotal bile acid transporters. Here, we present a new, potent CPL207280 agonist and compare it with fasiglifam in numerous in vitro and in vivo studies. CPL207280 showed greater potency than fasiglifam in a Ca2+ influx assay with a human GPR40 protein (EC50 = 80 vs. 270 nM, respectively). At the 10 µM concentration, it showed 3.9 times greater enhancement of glucose-stimulated insulin secretion in mouse MIN6 pancreatic β-cells. In Wistar Han rats and C57BL6 mice challenged with glucose, CPL207280 stimulated 2.5 times greater insulin secretion without causing hypoglycemia at 10 mg/kg compared with fasiglifam. In three diabetic rat models, CPL207280 improved glucose tolerance and increased insulin area under the curve by 212%, 142%, and 347%, respectively. Evaluation of potential off-target activity (Safety47) and selectivity of CPL207280 (at 10 μM) did not show any significant off-target activity. We conclude that CPL207280 is a potent enhancer of glucose-stimulated insulin secretion in animal disease models with no risk of hypoglycemia at therapeutic doses. Therefore, we propose the CPL207280 compound as a compelling candidate for type 2 diabetes treatment. SIGNIFICANCE STATEMENT: GPR40 is a well-known and promising target for diabetes. This study is the first to show the safety and effects of CPL207280, a novel GPR40/free fatty acid receptor 1 agonist, on glucose homeostasis both in vitro and in vivo in different diabetic animal models. Therefore, we propose the CPL207280 compound as a novel, glucose-lowering agent, overcoming the unmet medical needs of patients with type 2 diabetes.

122-LB: In Vitro Pharmacodynamic Studies of IDG-16177, a Potent GPR40 Agonist, for the Treatment of Type 2 Diabetes

G-protein-coupled receptor 40 (GPR40/FFA1/FFAR1), a clinically validated anti-diabetes target, enhances insulin secretion in type 2 diabetes. It is known that the effect of glucose-stimulated insulin secretion (GSIS) in pancreatic β cells is mediated primarily through Gq. However, in a recent study, it was found that GPR40 plays a role in both G protein-mediated and β-arrestin-mediated mechanisms, and fasiglifam (TAK-875), a partial GPR40 agonist discontinued in phase 3 clinical trials, induces insulin secretion by mediating β-arrestin rather than Gq. Therefore, by using stable GPR40 cell lines and β cells, we tried to confirm the signaling mechanism and efficacy of IDG-16177, which is being developed by Ildong Pharma in first-in-human study, as a GPR40 agonist. In cells expressing recombinant human, rat, and cynomolgus monkey GPR40, IDG-16177 dose-dependently increases intracellular free Ca2+ level, with EC50 of 114.3, 103.9, and 758.8 nM, respectively, showing no significant differences between human and rat (fasiglifam EC50= 75.2, 140.4, and 906.2 nM). IDG-16177 enhances β-arrestin recruitment, which has been shown to contribute to GPR40-mediated GSIS, with an EC50 of 68.0 nM and Emax of 99.4%, and is more efficacious and potent than fasiglifam (EC50= 154.0 nM; Emax= 88.0%). IDG-16177 exhibits EC50 of 0.8 nM and 110.6 nM, in inositol phosphate 1 (IP1) accumulation assay and extracellular signal-regulated kinase (ERK) activation assay, respectively. Although IDG-16177 shows no signal at the cAMP pathway like fasiglifam, IDG-16177 (0.1~3 μM)-treated group enhances more insulin secretion than fasiglifam (1~10 μM) in HIT-T15 β cells. These studies support the potential utility of IDG-16177 for the treatment of type 2 diabetes. Disclosure J. Yoon: None. Y. Jun: None. K. An: None. C. Hong: None. H. Kwak: None. I. Je: None. H. Song: None. H. Song: None. D. Lee: None. J. Kim: None. D. Hong: None. C. Shin: None. E. Jang: None. J. Kim: None. S. Lee: None.

A new synthetic dual agonist of GPR120/GPR40 induces GLP-1 secretion and improves glucose homeostasis in mice

G-protein coupled receptors 40 and 120 (GPR40 and GPR120) are increasingly emerging as potential therapeutic targets for the treatment of altered glucose homeostasis, and their agonists are under evaluation for their glucagon-like peptide-1 (GLP-1)-mediated therapeutic effects on insulin production and sensitivity. Here, we characterized a new dual GPR40 and GPR120 agonist (DFL23916) and demonstrated that it can induce GLP-1 secretion and improve glucose homeostasis.Resulting from a rational drug design approach aimed at identifying new dual GPR120/40 agonists able to delay receptor internalization, DFL23916 had a good activity and a very high selectivity towards human GPR120 (long and short isoforms) and GPR40, as well as towards their mouse orthologous, by which it induced both Gαq/11-initiated signal transduction pathways with subsequent Ca2+ intracellular spikes and G protein-independent signaling via β-arrestin with the same activity. Compared to the endogenous ligand alpha-linolenic acid (ALA), a selective GPR120 agonist (TUG-891) and a well-known dual GPR40 and GPR120 agonist (GW9508), DFL23916 was the most effective in inducing GLP-1 secretion in human and murine enteroendocrine cells, and this could be due to the delayed internalization of the receptor (up to 3 h) that we observed after treatment with DFL23916. With a good pharmacokinetic/ADME profile, DFL23916 significantly increased GLP-1 portal vein levels in healthy mice, demonstrating that it can efficiently induce GLP-1 secretion in vivo. Contrary to the selective GPR120 agonist (TUG-891), DFL23916 significantly improved also glucose homeostasis in mice undergoing an oral glucose tolerance test (OGTT).

A novel GPR120-selective agonist promotes insulin secretion and improves chronic inflammation

AimsThe present study aimed to disclose a potent and selective GPR120 agonist LXT34 and its anti-diabetic effects. Main methodsCalcium mobilization assay was used to measure the agonistic potency and selectivity of LXT34 in GPR120 or GPR40-overexpression Chinese hamster ovary (CHO) cells. Glucagon-like peptide-1 (GLP-1) release and glucose-stimulated insulin secretion (GSIS) were evaluated in human colonic epithelial cell line NCI-H716 and mouse insulinoma cell line MIN6 by enzyme-linked immunosorbent assay (ELISA), respectively. The anti-inflammatory effect was determined in lipopolysaccharide (LPS)-induced murine macrophage cell line RAW264.7. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed to assess the anti-diabetic effects of LXT34 in db/db mice, and chronic inflammation in liver and adipose tissues were investigated using histomorphology, immunoblot and gene expression analysis. Key findingsLXT34 was a potent GPR120 agonist with negligible activity toward human and mouse GPR40. LXT34 could potentiate GSIS and suppress LPS-induced inflammation in macrophages. LXT34 not only markedly improved glucose tolerance and insulin resistance, but also distinctly reduced macrophages infiltration, pro-inflammatory cytokines expression and JNK phosphorylation of both liver and adipose tissues in db/db mice. SignificanceLXT34, a novel and potent GPR120-selective agonist, showed beneficial effects on improving glucose homeostasis in obesity-related type 2 diabetes.

The synthesis of cis- and trans-3-(4-hydroxyphenyl)cyclobutanecarboxylic acids and the study of their derivatives as GPR-40 receptor ligands

Aim. To synthesize cis- and trans-isomers of 3-(4-hydroxyphenyl)cyclobutanecarboxylic acid and evaluate the biological activity of their derivatives against GPR-40.Results and discussion. Cis- and trans-isomers of 3-(4-hydroxyphenyl)cyclobutanecarboxylic acid were synthesized. The derivatives of this compound were tested as GPR-40 agonists and exhibited the micromolar activity.Experimental part. The methyl ester of 3-(4-hydroxyphenyl)cyclobutanecarboxylic acid was obtained as a mixture of cis/trans-isomers in 3 steps starting from a commercially available 3-oxocyclobutanecarboxylic acid. Further transformation of this compound into isomerically pure 3-(4-hydroxyphenyl)cyclobutanecarboxylic acids was achieved in five steps based on the chromatographic separation of diastereomeric amide derivatives. New GPR-40 ligands were obtained by O-alkylation of a phenolic oxygen atom of the corresponding carboxylic acid methyl ester. The biological activity of the agonists synthesized was studied using a fluorometric bioassay and the engineered Chinese hamster ovary (CHO) stable cell line expressing the human GPR-40.Conclusions. An effective synthetic approach to 3-(4-hydroxyphenyl)cyclobutanecarboxylic acid allowing to isolate two single cis/trans-stereoisomers of this compound has been developed. In order to demonstrate the possibility for the bioisosteric replacement of the ethylene moiety in the structures of free fatty acid receptor (FFAR) agonists by the cyclobutane ring, four new GPR-40 ligands possessing the micromolar activity have been synthesized.Received: 22.08.2020 Revised: 11.10.2020 Accepted: 17.10.2020

CoMFA, CoMSIA and HQSAR Analysis of 3-aryl-3-ethoxypropanoic Acid Derivatives as GPR40 Modulators.

Human GPR40 receptor, also known as free fatty-acid receptor 1, is a Gprotein- coupled receptor that binds long chain free fatty acids to enhance glucose-dependent insulin secretion. In order to improve the resistance and efficacy, computational tools were applied to a series of 3-aryl-3-ethoxypropanoic acid derivatives. A relationship between the structure and biological activity of these compounds, was derived using a three-dimensional quantitative structure-activity relationship (3D-QSAR) study using CoMFA, CoMSIA and two-dimensional QSAR study using HQSAR methods. Building the 3D-QSAR models, CoMFA, CoMSIA and HQSAR were performed using Sybyl-X software. The ratio of training to test set was kept 70:30. For the generation of 3D-QSAR model three different alignments were used namely, distill, pharmacophore and docking based alignments. Molecular docking studies were carried out on designed molecules using the same software. Among all the three methods used, Distill alignment was found to be reliable and predictive with good statistical results. The results obtained from CoMFA analysis q2, r2cv and r2 pred were 0.693, 0.69 and 0.992 respectively and in CoMSIA analysis q2, r2cv and r2pred were 0.668, 0.648 and 0.990. Contour maps of CoMFA (lipophilic and electrostatic), CoMSIA (lipophilic, electrostatic, hydrophobic, and donor) and HQSAR (positive & negative contribution) provided significant insights i.e. favoured and disfavoured regions or positive & negative contributing fragments with R1 and R2 substitutions, which gave hints for the modifications required to design new molecules with improved biological activity. 3D-QSAR techniques were applied for the first time on the series 3-aryl-3- ethoxypropanoic acids. All the models (CoMFA, CoMSIA and HQSAR) were found to be satisfactory according to the statistical parameters. Therefore such a methodology, whereby maximum structural information (from ligand and biological target) is explored, gives maximum insights into the plausible protein-ligand interactions and is more likely to provide potential lead candidates has been exemplified from this study.

Endocannabinoids and endocannabinoid-like molecules are present in foods, blood and ileal fluids from ileostomy subjects: insight into possible metabolic implications

AbstractThe endocannabinoid system is a lipid signalling system with several regulatory functions throughout the body including regulation of appetite, food intake, macronutrient metabolism, pain sensation, blood pressure, mood, cognition and immunity. It consists of endocannabinoids (ECs), their receptors and enzymes involved in their synthesis and degradation. The two best-characterized endocannabinoids are N-arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG). They are ligands of cannabinoid receptors CB1 and CB2 which are located in the central nervous system (CNS) but also in in the enteric nervous system, in the liver and in the adipose tissue.Several structural congeners of ECs including N-acylethanolamines (NAEs) such as oleoylethanolamine (OEA), linoleyethanolamine (LEA), and palmitoyletahanolamine (PEA), show similar mechanisms of action, tissue distribution as well as pathways of formation and breakdown. They are considered “endocannabinoid-like” molecules acting through receptors that are located both in CNS and in the gastro-intestinal tract mucosa such as the G-protein coupled receptor 119 (GPR119) and peroxisome proliferator-activated receptors (PPARs). NAEs display EC50 values for human GPR119 and PPAR-α between 65 ng/mL and 1000 ng/mL. Some evidence indicated that NAEs, their phosphorylated precursors N-acylphosphatidylethanolamines (NAPEs) and ECs are also present in food. Thus, we developed a food database of these molecules and we calculated the daily dietary intake in a healthy population.This study aimed to evaluate whether the concentrations of NAPEs, NAEs and ECs in the human intestinal lumen may support their activity through the receptors lining in the gastro-intestinal tract and if they correlated with those in plasma.The observational study (16/NI/0267, Ulster University) involved 35 ileostomists (18F/17M, aged 18–70 y, BMI 17–40 kg/m2) who collected overnight fasting samples of ileal fluid and plasma. The concentrations of NAEs, NAPEs and ECs in biological samples were determined by LC-HRMS.Data showed that NAEs and NAPEs were present in ileal fluids and plasma from all subjects ranging between 46851.0–104742.8 ng/mL and 0.3–59.6 ng/mL in ileal samples and 1159.4–3985.7 ng/mL and 0.19–1.24 ng/mL in plasma, respectively. Contrarily, no ECs in ileal fluids were found except 2-AG in two ileal samples whereas they ranged between 1.6–22.3 ng/mL in plasma. Differences between genders and associations of plasma levels with individual energy intakes were found.Altogether, the data demonstrated that NAEs in the intestinal lumen are sufficient to elicit metabolic responses through the gastro-intestinal receptors.

Design and biological evaluation of tetrahydropyridine derivatives as novel human GPR119 agonists

A series of novel tetrahydropyridine derivatives were prepared and evaluated using cell-based measurements. Systematic optimization of general structure G-1 led to the identification of compound 35 (EC50 = 4.9 nM) and 37 (EC50 = 8.8 nM) with high GPR119 agonism activity and moderate clog P. Through single and long-term pharmacodynamic experiments, we found that compound35 showed a hypoglycemic effect and may have an effect on improving basal metabolic rate in DIO mice. Both in vitro and in vivo tests indicated that compound 35 was a potential potent GPR119 agonist in allusion to T2DM treatment.

HM47118A, a novel insulinotropic GPR119 agonist and potential oral antidiabetic agent

AimsThe G protein-coupled receptor 119 (GPR119), mainly expressed in the pancreas and gastrointestinal tract, increases the intracellular cyclic AMP accumulation, enhances glucose-dependent insulin secretion from pancreatic β cells, and promotes glucagon-like peptide-1 (GLP-1) production by intestinal L cells. We investigated the activities of a novel GPR119 agonist, HM47118A, in vitro and in vivo. MethodsIn vitro HM47118A activities were evaluated in several cell lines. Mice, rats, and dogs were administered single intravenous or oral doses of HM47118A to evaluate its pharmacokinetics, while its antidiabetic efficacy was evaluated in Zucker diabetic fatty (ZDF) rats. ResultsThe half-maximal effective concentrations of HM47118A were 2.0 and 21.8 nM for the activation of human GPR119 in GPR119-CRE-bla CHO-K1 cells and stimulation of GLP-1 secretion by GLUTag cells, respectively. HM47118A increased insulin secretion by MIN-6 cells and the proliferation of NIT-1 pancreatic β cells. The compound showed favorable pharmacokinetic profiles in all three animal models. Administration of HM47118A but not sitagliptin to ZDF rats for 56 days significantly reduced the blood glucose and glycated hemoglobin (HbA1c) levels, increased postprandial insulin levels, and preserved the pancreatic β cell mass. ConclusionsHM47118A showed significant antidiabetic potential and may be an effective oral treatment for diabetes.

Pharmacokinetics of TAK‐875 and its toxic metabolite TAK‐875‐ acylglucuronide in rat plasma by liquid chromatography tandem mass spectrometry

TAK-875 is a selective partial agonist of human GPR40 receptor, which was unexpectedly terminated at phase III clinical trials owing to its severe hepatotoxicity. The purpose of this study was to investigate the pharmacokinetics of TAK-875 and its toxic metabolite TAK-875-acylglucuronide in rat plasma by liquid chromatography tandem mass spectrometry (LC-MS/MS). Plasma samples were extracted with ethyl acetate and chromatographic separations were achieved on a C18 column with water and acetonitrile containing 0.05% ammonium hydroxide as mobile phase. The sample was detected in selected reaction monitoring mode with precursor-to-product ion transitions being m/z 523.2 → 148.1, m/z 699.3 → 113.1 and m/z 425.2 → 113.1 for TAK-875, TAK-875-acylglucuronide and IS, respectively. The assay showed good linearity over the tested concentration ranges (r > 0.9993), with the LLOQ being 0.5 ng/mL for both analytes. The extraction recovery was >78.45% and no obvious matrix effect was detected. The highly sensitive LC-MS/MS method has been further applied for the pharmacokinetic study of TAK-875 and its toxic metabolite TAK-875-acylglucuronide in rat plasma. Pharmacokinetics results revealed that oral bioavailability of TAK-875 was 86.85%. The in vivo exposures of TAK-875-acylglucuronide in terms of AUC0-t were 17.54 and 22.29% of that of TAK-875 after intravenous and oral administration, respectively.

Structural basis for GPR40 allosteric agonism and incretin stimulation

Activation of free fatty acid receptor 1 (GPR40) by synthetic partial and full agonists occur via distinct allosteric sites. A crystal structure of GPR40-TAK-875 complex revealed the allosteric site for the partial agonist. Here we report the 2.76-Å crystal structure of human GPR40 in complex with a synthetic full agonist, compound 1, bound to the second allosteric site. Unlike TAK-875, which acts as a Gαq-coupled partial agonist, compound 1 is a dual Gαq and Gαs-coupled full agonist. compound 1 binds in the lipid-rich region of the receptor near intracellular loop 2 (ICL2), in which the stabilization of ICL2 by the ligand is likely the primary mechanism for the enhanced G protein activities. The endogenous free fatty acid (FFA), γ-linolenic acid, can be computationally modeled in this site. Both γ-linolenic acid and compound 1 exhibit positive cooperativity with TAK-875, suggesting that this site could also serve as a FFA binding site.

The role of pharmacology to produce firuglipel (DS-8500a), an orally available GPR119 agonist for type 2 diabetes mellitus

GPR119 (G-protein coupled receptor 119) has been shown to be highly expressed in the lower small intestinal and colorectal L-cells and pancreatic β-cells, and mediates intracellular cAMP concentration, glucagon like peptide (GLP-1) secretion, and glucose stimulated insulin secretion (GSIS). As the next generation for the treatment of type 2 diabetes mellitus (T2DM), GPR119 agonist has been intensively studied by pharmaceutical companies and a lot of patents have been applied by them. In such highly competitive condition, biological differentiation and to find an advantage among GPR119 agonists were necessary to proceed the candidate compound in further clinical investigation. Firuglipel (DS-8500a) is an orally available GPR119 agonist synthesized in DAIICHI SANKYO CO., LTD (DS). It was originated from DS-chemical library and optimized in the aspect of bioavailability and safety. Firuglipel had a higher intrinsic activity (IA) of the production of intracellular cAMP in human GPR119 expressing CHO-K1 cells than those of other GPR119 agonists studied. The level of IA in each GPR119 agonist was correlated with the existence of agonist conformer. In parallel with the study for the differentiation from other GPR119 agonists, we compared firuglipel with dipeptidyl peptide-4 (DPP-4) inhibitor in NONcNZO10/LtJ mice and evaluated their combination in streptozotocin (STZ) treated C57BL/6J mice to clarify future positioning among anti-diabetics therapy. These pharmacological studies illustrated here can draw out a clinical value of compound and expected to lead the production of first-in-class agent in pharmaceutical companies.

Discovery of 5-methyl-2-(4-((4-(methylsulfonyl)benzyl)oxy)phenyl)-4-(piperazin-1-yl)pyrimidine derivatives as novel GRP119 agonists for the treatment of diabetes and obesity.

A series of fused-pyrimidine derivatives were prepared and evaluated for their agonistic activities against human GPR119. Compound 9i showed high potent agonistic activity against HEK293T cells over-expressing human GPR119 and improved glucose tolerance in dose-dependent manner, as well as promoted insulin secretion. In a DIO mice model, 9i also ameliorated the obese-related symptoms by decreasing the body weights without markedly changing food intake, normalized some serum biomarkers, such as ALT, AST, ALP, GLU, CHOL, HDL, and LDL, and exerted therapeutic activity on fat deposition in liver tissue. We consider 9i to have utility as a GPR119 agonists for the treatment of type 2 diabetes mellitus and obese-related symptoms.

In vitro and in vivo effects of kisspeptin antagonists p234, p271, p354, and p356 on GPR54 activation.

Kisspeptins (KPs) and their receptor (GPR54 or KiSS1R) play a key-role in regulation of the hypothalamic-pituitary-gonadal axis and are therefore interesting targets for therapeutic interventions in the field of reproductive endocrinology. As dogs show a rapid and robust LH response after the administration of KP10, they can serve as a good animal model for research concerning KP signaling. The aims of the present study were to test the antagonistic properties of KP analogs p234, p271, p354, and p356 in vitro, by determining the intracellular Ca2+ response of CHEM1 cells that stably express human GPR54, and to study the in vivo effects of these peptides on basal plasma LH concentration and the KP10-induced LH response in female dogs. Exposure of the CHEM1 cells to KP-10 resulted in a clear Ca2+ response. P234, p271, p354, and p356 did not prevent or lower the KP10-induced Ca2+ response. Moreover, the in vivo studies in the dogs showed that none of these supposed antagonists lowered the basal plasma LH concentration and none of the peptides lowered the KP10-induced LH response. In conclusion, p234, p271, p354, and p356 had no antagonistic effects in vitro nor any effect on basal and kisspeptin-stimulated plasma LH concentration in female dogs.

Structural basis for the cooperative allosteric activation of the free fatty acid receptor GPR40.

Clinical studies indicate that partial agonists of the G-protein-coupled, free fatty acid receptor 1 GPR40 enhance glucose-dependent insulin secretion and represent a potential mechanism for the treatment of type 2 diabetes mellitus. Full allosteric agonists (AgoPAMs) of GPR40 bind to a site distinct from partial agonists and can provide additional efficacy. We report the 3.2-Å crystal structure of human GPR40 (hGPR40) in complex with both the partial agonist MK-8666 and an AgoPAM, which exposes a novel lipid-facing AgoPAM-binding pocket outside the transmembrane helical bundle. Comparison with an additional 2.2-Å structure of the hGPR40-MK-8666 binary complex reveals an induced-fit conformational coupling between the partial agonist and AgoPAM binding sites, involving rearrangements of the transmembrane helices 4 and 5 (TM4 and TM5) and transition of the intracellular loop 2 (ICL2) into a short helix. These conformational changes likely prime GPR40 to a more active-like state and explain the binding cooperativity between these ligands.