GPR119 Agonists Research Articles

Central GPR55 may prevent nicotine reinforcing actions: a preliminary study.

GPR55 is an orphan receptor whose endogenous agonists include lysophosphatidylinositol (LPI) and N‑acetylethanolamides (NAEs), such as palmitoylethanolamide (PEA) and anandamide. Furthermore, its physiology in the central nervous system involves motor coordination, procedural and spatial memory, pain, and anxiety, among others. Recent reports indicate that systemic injections of O‑1602 (a GPR55 and GPR18 agonist) blocked the reinforcing effects of morphine and nicotine in the conditioned place preference (CPP) paradigm, suggesting a possible participation of peripheral and/or central GPR55/GPR18 in brain reward/anti‑reward systems. In this pilot study, the endogenous GPR55 agonists LPI and PEA, the highly selective GPR55 synthetic agonist ML184 or the selective GPR55 antagonist ML193 were injected to examine their pharmacological effects on the reinforcing actions of nicotine in the CPP paradigm. Our preliminary study shows that injections of LPI, PEA, ML184 and ML193 interfered with the change in place preference induced by nicotine via mechanisms that remain to be identified (which probably include central GPR55).

Lysophosphatidylinositol Induced Morphological Changes and Stress Fiber Formation through the GPR55-RhoA-ROCK Pathway.

We previously reported that lysophosphatidylinositol (LPI) functions as an endogenous agonist of GPR55, a novel cannabinoid receptor. However, the physiological roles of LPI-GPR55 have not yet been elucidated in detail. In the present study, we found that LPI induced morphological changes in GPR55-expressing HEK293 cells. LPI induced the cell rounding of GPR55-expressing HEK293 cells but not of empty-vector-transfected cells. LPI also induced the activation of small GTP-binding protein RhoA and increased stress fiber formation in GPR55-expressing HEK293 cells. The inhibition of RhoA and Rho kinase ROCK by the C3 exoenzyme and the ROCK inhibitor reduced LPI-induced cell rounding and stress fiber formation. These results clearly indicated that the LPI-induced morphological changes and the assembly of the cytoskeletons were mediated through the GPR55-RhoA-ROCK pathway.

The Zinc-sensing Receptor (GPR39) Modulates Declarative Memory and Age-related Hippocampal Gene Expression in Male Mice

As a neuromodulator, zinc regulates synaptic plasticity, learning and memory. Synaptic zinc is also a crucial factor in the development of toxic forms of amyloid beta protein and, subsequently, of Alzheimer’s dementia (AD). Therefore, efforts to pinpoint mechanisms underlying zinc-dependent cognitive functions might aid AD research, by providing potential novel targets for drugs. One of the most understudied proteins in this regard is a zinc-sensing metabotropic receptor: GPR39. In this study we investigated the impact of GPR39 knock-out (KO) on age-related memory decline in mice of both sexes, by comparing them to age-matched wild-type (WT) littermates. We also tested the effects of a GPR39 agonist (TC-G 1008) on declarative memory of old animals, and its disruption in adult mice. We observed episodic-like memory (ELM) and spatial memory (SM) deficits in male GPR39 KO mice, as well as intact procedural memory in GPR39 KO mice regardless of age and sex. ELM was also absent in old WT male mice, and all female mice regardless of their genotype. Acute application of TC-G 1008 (10 mg/kg) reversed a deficit in two of three ELM components in old WT male mice, and had no promnesic effect on consolidation interference of ELM in adult WT mice. We discuss the possible neurobiological mechanisms and the translational value of these results for potential add-on pharmacotherapy of AD aimed at the zinc-sensing receptor.

Mitochondrial remodeling and ischemic protection by G protein-coupled receptor 35 agonists.

Kynurenic acid (KynA) is tissue protective in cardiac, cerebral, renal, and retinal ischemia models, but the mechanism is unknown. KynA can bind to multiple receptors, including the aryl hydrocarbon receptor, the a7 nicotinic acetylcholine receptor (a7nAChR), multiple ionotropic glutamate receptors, and the orphan G protein-coupled receptor GPR35. Here, we show that GPR35 activation was necessary and sufficient for ischemic protection by KynA. When bound by KynA, GPR35 activated Gi- and G12/13-coupled signaling and trafficked to the outer mitochondria membrane, where it bound, apparantly indirectly, to ATP synthase inhibitory factor subunit 1 (ATPIF1). Activated GPR35, in an ATPIF1-dependent and pertussis toxin-sensitive manner, induced ATP synthase dimerization, which prevented ATP loss upon ischemia. These findings provide a rationale for the development of specific GPR35 agonists for the treatment of ischemic diseases.

Presynaptic nigral GPR55 receptors stimulate [3 H]-GABA release through [3 H]-cAMP production and PKA activation and promote motor behavior.

Striatal medium-sized spiny neurons express mRNA and protein of GPR55 receptors that stimulate neurotransmitter release; thus, GPR55 could be sent to nigral striatal projections, where it might modulate GABA release and motor behavior. Here, we study the presence of GPR55 receptors at striato-nigral terminals, their modulation of GABA release, their signaling pathway, and their effect on motor activity. By double immunohistochemistry, we found the colocation of GPR55 protein and substance P in the dorsal striatum. In slices of the rat substantia nigra, the GPR55 agonists LPI and O-1602 stimulated [3 H]-GABA release induced by high K+ depolarization in a dose-dependent manner. The antagonists CID16020046 and cannabidiol prevented agonist stimulation in a dose-dependent way. The effect of GPR55 on nigral [3 H]-GABA release was prevented by lesion of the striatum with kainic acid, which was accompanied by a decrement of GPR55 protein in nigral synaptosomes, indicating the presynaptic location of receptors. The depletion of internal Ca2+ stores with thapsigargin did not prevent the effect of LPI on [3 H]-GABA release, but the remotion or chelation of external calcium did. Blockade of Gi, Gs, PLC, PKC, or dopamine D1 receptor signaling proteins did not prevent the effect of GPR55 on release. However, the activation of GPR55 stimulated [3 H]-cAMP accumulation and PKA activity. Intranigral unilateral injection of LPI induces contralateral turning. This turning was prevented by CID16020046, cannabidiol, and bicuculline but not by SCH 23390. Our data indicate that presynaptic GPR55 receptors stimulate [3 H]-GABA release at striato-nigral terminals through [3 H]-cAMP production and stimulate motor behavior.

Molecular docking and identification of G-protein-coupled receptor 120 (GPR120) agonists as SARS COVID-19 MPro inhibitors

COVID-19 has become a pandemic, and any new drug for treating the disease could save millions of lives. Several drugs already in use for other diseases and medical conditions are repurposed for treating COVID-19 in an attempt to find treatment for the disease without spending research time on ADME TOX and other studies on side effects. In this exercise, the drugs repurposed are from antiviral, antibiotics, antiviral for HIV and HCV, anti-cancer, natural medicines, etc. Possible repurposing anti-diabetic GPR-120 agonists used as for SAR-CoV-2 is attempted in the study by carrying out docking of 68 GPR-120 agonists. Ten of these compounds were found to have docking scores −8.3 to −8.0, and the best docking score was observed for an arylsulfonamide and a biarylpropanoic acid belonging to GPR120 agonists previously evaluated for the treatment of type II diabetes. These GPR120 agonists could serve as start point for novel inhibitors for the discovery of drugs to treat COVID-19.

Anti-Inflammatory Properties of KLS-13019: a Novel GPR55 Antagonist for Dorsal Root Ganglion and Hippocampal Cultures.

KLS-13019, a novel devised cannabinoid-like compound, was explored for anti-inflammatory actions in dorsal root ganglion cultures relevant to chemotherapy-induced peripheral neuropathy (CIPN). Time course studies with 3µM paclitaxel indicated > 1.9-fold increases in immunoreactive (IR) area for cell body GPR55 after 30min as determined by high content imaging. To test for reversibility of paclitaxel-induced increases in GPR55, cultures were treated for 8h with paclitaxel alone and then a dose response to KLS-13019 added for another 16h. This "reversal" paradigm indicated established increases in cell body GPR55 IR areas were decreased back to control levels. Because GPR55 had previously reported inflammatory actions, IL-1β and NLRP3 (inflammasome-3 marker) were also measured in the "reversal" paradigm. Significant increases in all inflammatory markers were produced after 8h of paclitaxel treatment alone that were reversed to control levels with KLS-13019 treatment. Accompanying studies using alamar blue indicated that decreased cellular viability produced by paclitaxel treatment was reverted back to control levels by KLS-13019. Similar studies conducted with lysophosphatidylinositol (GPR55 agonist) in DRG or hippocampal cultures demonstrated significant increases in neuritic GPR55, NLRP3 and IL-1β areas that were reversed to control levels with KLS-13019 treatment. Studies with a human GPR55-β-arrestin assay in Discover X cells indicated that KLS-13019 was an antagonist without agonist activity. These studies indicated that KLS-13019 has anti-inflammatory properties mediated through GPR55 antagonist actions. Together with previous studies, KLS-13019 is a potent neuroprotective, anti-inflammatory cannabinoid with therapeutic potential for high efficacy treatment of neuropathic pain.

SAT178 - Inhibition of NLRP3 inflammasome by GPR40 agonists

SAT178 - Inhibition of NLRP3 inflammasome by GPR40 agonists

Alterations of Serum Magnesium Concentration in Animal Models of Seizures and Epilepsy-The Effects of Treatment with a GPR39 Agonist and Knockout of the Gpr39 Gene.

Several ligands have been proposed for the GPR39 receptor, including the element zinc. The relationship between GPR39 and magnesium homeostasis has not yet been examined, nor has such a relationship in the context of seizures/epilepsy. We used samples from mice that were treated with an agonist of the GPR39 receptor (TC-G 1008) and underwent acute seizures (maximal electroshock (MES)- or 6-hertz-induced seizures) or a chronic, pentylenetetrazole (PTZ)-induced kindling model of epilepsy. MES seizures and PTZ kindling, unlike 6 Hz seizures, increased serum magnesium concentration. In turn, Gpr39-KO mice that underwent PTZ kindling displayed decreased concentrations of this element in serum, compared to WT mice subjected to this procedure. However, the levels of expression of TRPM7 and SlC41A1 proteins—which are responsible for magnesium transport into and out of cells, respectively—did not differ in the hippocampus between Gpr39-KO and WT mice. Furthermore, laser ablation inductively coupled plasma mass spectrometry applied to hippocampal slices did not reveal differences in magnesium levels between the groups. These data show the relationship between magnesium homeostasis and certain types of acute or chronic seizures (MES seizures or PTZ kindling, respectively), but do not explicitly support the role of GPR39 in mediating magnesium balance in the hippocampus in the latter model. However, decreased expression of TRPM7 and increased expression of SLC41A1—which were observed in the hippocampi of Gpr39-KO mice treated with TC-G 1008, in comparison to WT mice that received the same treatment—implicitly support the link between GPR39 and hippocampal magnesium homeostasis.

Novel Potent and Selective Agonists of the GPR55 Receptor Based on the 3-Benzylquinolin-2(1H)-One Scaffold.

A growing body of evidence underlines the crucial role of GPR55 in physiological and pathological conditions. In fact, GPR55 has recently emerged as a therapeutic target for several diseases, including cancer and neurodegenerative and metabolic disorders. Several lines of evidence highlight GPR55′s involvement in the regulation of microglia-mediated neuroinflammation, although the exact molecular mechanism has not been yet elucidated. Nevertheless, there are only a limited number of selective GPR55 ligands reported in the literature. In this work, we designed and synthesized a series of novel GPR55 ligands based on the 3-benzylquinolin-2(1H)-one scaffold, some of which showed excellent binding properties (with Ki values in the low nanomolar range) and almost complete selectivity over cannabinoid receptors. The full agonist profile of all the new derivatives was assessed using the p-ERK activation assay and a computational study was conducted to predict the key interactions with the binding site of the receptor. Our data outline a preliminary structure–activity relationship (SAR) for this class of molecules at GPR55. Some of our compounds are among the most potent GPR55 agonists developed to date and could be useful as tools to validate this receptor as a therapeutic target.

Pharmacological Activation of GPR55 Improved Cognitive Impairment Induced by Lipopolysaccharide in Mice.

Our previous research found that activation of GPR55 can alleviate cognitive impairment induced by amyloid-beta 1-42 (Aβ1-42) and streptozotocin in mice, but the role of GPR55 in the pathogenesis of cognitive impairment remains unknown. Here, we used a lipopolysaccharide (LPS) mouse model to further investigate the role and mechanism of O-1602, a GPR55 agonist, on cognitive dysfunction. ICR mice were treated with an intracerebroventricular (i.c.v.) injection of LPS, followed by cognitive function tests. The expression of GPR55, NF-κB p65, caspase-3, Bax, and Bcl-2 in the hippocampus was examined by Western blotting. Inflammatory cytokines and microglia were detected by ELISA kit and immunohistochemical analyses, respectively. The levels of MDA, GSH, SOD, and CAT were examined by assay kits. Furthermore, TUNEL-staining was used to detect neuronal apoptosis. Our results showed that i.c.v. injection of LPS in mice exhibited impaired performance in the behavior tests, which were ameliorated by O-1602 treatment (2.0 or 4.0 μg/mouse, i.c.v.). Importantly, we found that O-1602 treatment reversed GPR55 downregulation, decreased the expression of NF-κB p65, suppressed the accumulation of proinflammatory cytokines and microglia activation, increased the anti-inflammatory cytokines, and reduced the levels of MDA, increased the levels of GSH, SOD, and CAT in the hippocampus. In addition, O-1602 treatment also significantly reduced Bax and increased Bcl-2 expression as well as decreased caspase-3 activity and TUNEL-positive cells in the hippocampus. These observations indicate that O-1602 may ameliorate LPS-induced cognition deficits via inhibiting neuroinflammation, oxidative stress, and apoptosis mediated by the NF-κB pathway in mice.

Agonism of GPR120 Prevented High Glucose-Induced Apoptosis of Retinal Endothelial Cells through Inhibiting NLRP3 Inflammasome

GPR120 has been reported to ameliorate inflammation in diabetes and diabetic complications. In this study, GW9508, the GPR120 agonist, was utilized in human retinal microvascular endothelial cells (HRMECs) exposed to high glucose (HG) to investigate the involvement of GPR120 in cellular viability and apoptosis as well as the association with the NLRP3 inflammasome. The expression of GPR120 in HRMECs cultured under HG was firstly detected by Western blotting. HRMECs were then assigned to the normal control, GW9508, HG, and HG + GW9508 groups. The expression of the NLRP3 inflammasome consists of NLRP3, ASC, and caspase-1 and was detected by Western blotting and the downstream IL-1β and IL-18 by ELISA. The cellular viability and apoptosis of HRMECs were detected by CCK-8 and flow cytometry, respectively. The expressions of apoptosis-related proteins Bax and Bcl-2 were detected by Western blotting. Finally, nonspecific siRNA (NS) or GPR120 siRNA (siGPR120) was transfected to the cells, followed by stimulation with or without GW9508 or HG, and the expression of NLRP3, ASC, and caspase-1 were detected by Western blotting in these groups. GPR120 is expressed in HRMECs, and HG can reduce its expression in a time-dependent manner. GW9508 can attenuate inflammation by reducing the expression of NLRP3, ASC, caspase-1, IL-1β, and IL-18 under HG. GW9508 rescues the viability of HRMCs and reduces cell apoptosis by preventing an increase in Bax expression and the reduction in Bcl-2 expression. Additionally, knockdown of GPR120 by siRNA weakened the effects of GW9508 on NLRP3 inflammasome expression. Activation of GPR120 protects retinal vascular endothelial cells from HG through inhibiting NLRP3 inflammasome. Thus, GPR120 might be a potential therapeutic target to reduce retinal endothelial damage in diabetic retinopathy.

Effects of GPR139 agonism on effort expenditure for food reward in rodent models: Evidence for pro-motivational actions

Apathy, deficiency of motivation including willingness to exert effort for reward, is a common symptom in many psychiatric and neurological disorders, including depression and schizophrenia. Despite improved understanding of the neurocircuitry and neurochemistry underlying normal and deficient motivation, there is still no approved pharmacological treatment for such a deficiency. GPR139 is an orphan G protein-coupled receptor expressed in brain regions which contribute to the neural circuitry that controls motivation including effortful responding for reward, typically sweet gustatory reward. The GPR139 agonist TAK-041 is currently under development for treatment of negative symptoms in schizophrenia which include apathy. To date, however, there are no published preclinical data regarding its potential effect on reward motivation or deficiencies thereof. Here we report in vitro evidence confirming that TAK-041 increases intracellular Ca2+ mobilization and has high selectivity for GPR139. In vivo, TAK-041 was brain penetrant and showed a favorable pharmacokinetic profile. It was without effect on extracellular dopamine concentration in the nucleus accumbens. In addition, TAK-041 did not alter the effort exerted to obtain sweet gustatory reward in rats that were moderately food deprived. By contrast, TAK-041 increased the effort exerted to obtain sweet gustatory reward in mice that were only minimally food deprived; furthermore, this effect of TAK-041 occurred both in control mice and in mice in which deficient effortful responding was induced by chronic social stress. Overall, this study provides preclinical evidence in support of GPR139 agonism as a molecular target mechanism for treatment of apathy.

Human Milk Oligosaccharide L‐N‐Tetraose Activates GPR35 on Vagal Afferent Neurons In Vitroand Reduces High Fat Diet‐Induced Obesity in Male Mice

Obesity is associated with altered gut microbiota; dietary supplementation with prebiotics improves metabolic outcomes in obesity, an effect ascribed to improved microbial dysbiosis. However, alternative mechanisms have not been fully explored. We have shown that prebiotic milk oligosaccharides (MOs) decrease weight gain and food intake in mice fed a high‐fat diet (HFD), and improve cholecystokinin (CCK)‐induced satiety signaling. It has recently been shown that the human MO lacto‐N‐tetraose (LNT) is a ligand for the G‐protein coupled receptor, GPR35. GPR35 is highly expressed by vagal afferent neurons (VAN) where it is co‐expressed with the CCKAR. HFD reduces endogenous GPR35 ligands and sensitivity to CCK, but the role of GPR35 and its ligands eg LNT, in satiety signaling via the vagal afferent pathway have not been investigated. Here we test the hypothesis that LNT reduces HFD‐induced weight gain and hyperphagia in mice via a direct effect on GPR35 expressed by VAN.MethodsMice were maintained on low‐fat diet (10% kcal fat), HFD (45% fat kcal), or HFD supplemented with 10% LNT for 8 weeks (male, n=5‐9/group). To determine if VAN are directly activated by GPR35 ligands, VAN from adult male Wistar rats were cultured and treated with the GPR35 agonist zaprinast (100 µM), LNT (10 mM), or D‐lactose (constituent of LNT; 10 mM) for 15 minutes after 1 hour pre‐incubation with the GPR35 competitive antagonist CID‐2745687 (100 µM) or vehicle (n=4/treatment). Phosphorylation of extracellular regulated kinase (ERK) relative to total ERK (pERK/ERK) was determined by western blot and used as an indicator of VAN activation.ResultsLNT administration significantly reduced body weight, fat mass, and improved HFD‐induced hyperphagia (p<0.05). Treatment of VAN with the GPR35 agonist zaprinast increased pERK/ERK (p<0.05) relative to vehicle; zaprinast‐induced activation was prevented by the CID‐2745687. LNT, but not D‐lactose, also activated VAN, an effect inhibited by the GPR35 antagonist.ConclusionsLNT may decrease food intake via a direct effect on VAN, possibly by increasing sensitivity to peripheral satiety signals. This work reveals a potential peripheral therapeutic target for ameliorating diet‐induced weight gain.

Endogenous Lipid-GPR120 Signaling Modulates Pancreatic Islet Homeostasis to Different Extents.

Long-chain fatty acids (LCFAs) are not only energy sources but also serve as signaling molecules. GPR120, an LCFA receptor, plays key roles in maintaining metabolic homeostasis. However, whether endogenous ligand-GPR120 circuits exist and how such circuits function in pancreatic islets are unclear. Here, we found that endogenous GPR120 activity in pancreatic δ-cells modulated islet functions. At least two unsaturated LCFAs, oleic acid (OA) and linoleic acid (LA), were identified as GPR120 agonists within pancreatic islets. These two LCFAs promoted insulin secretion by inhibiting somatostatin secretion and showed bias activation of GPR120 in a model system. Compared with OA, LA exerted higher potency in promoting insulin secretion, which is dependent on β-arrestin2 function. Moreover, GPR120 signaling was impaired in the diabetic db/db model, and replenishing OA and LA improved islet function in both the db/db and streptozotocin-treated diabetic models. Consistently, the administration of LA improved glucose metabolism in db/db mice. Collectively, our results reveal that endogenous LCFA-GPR120 circuits exist and modulate homeostasis in pancreatic islets. The contributions of phenotype differences caused by different LCFA-GPR120 circuits within islets highlight the roles of fine-tuned ligand-receptor signaling networks in maintaining islet homeostasis.

Highly Enantioselective Rhodium-Catalyzed Transfer Hydrogenation of Tetrasubstituted Olefins: Application toward the Synthesis of GPR40 Agonist MK-2305.

A highly efficient enantioselective synthesis for the potent G-protein-coupled receptor 40 agonist MK-2305 was developed. The key tetrasubstituted olefin was prepared via a stereoselective Mukaiyama aldol reaction/elimination sequence. The highly enantioselective rhodium-catalyzed transfer hydrogenation of the tetrasubstituted olefin afforded the target compound MK-2305 in excellent optical and chemical purity. The key asymmetric transfer hydrogenation proceeds in excellent yields and enantioselectivities for a variety of substrates. The superior reactivity of the tethered catalysts was revealed by NMR studies.

Species differences between rats and primates (humans and monkeys) in complex cleavage pathways of DS-8500a characterized by 14C-ADME studies in humans and monkeys after administration of two radiolabeled compounds and in vitro studies

Our previous study in rats demonstrated that the metabolic pathways of DS-8500a, a novel GPR119 agonist, include cleavage pathways: reductive cleavage of the oxadiazole ring in the liver and hydrolysis of the amide side chain. In the present study, in vivo metabolic profiling in humans and monkeys after the oral administration of two 14C-labeled compounds was performed to investigate species differences of the cleavage pathways. In monkeys, the oxadiazole ring-cleaved metabolites were mainly detected in feces, but not observed in bile, unlike in rats, suggesting that the reductive ring-opening metabolism occurs in the gastrointestinal tract. In vitro incubation with enterobacterial culture media demonstrated that the reductive cleavage of the oxadiazole ring in humans and monkeys was considerably faster than that in rats. The other cleavage metabolite (M20), produced via hydrolysis of the amide side chain, was detected as the major plasma metabolite in humans and monkeys, and its subsequent metabolite (M21) was excreted in feces, whereas M21 was not a major component in rats, indicating a notable species difference in the amide hydrolysis. In conclusion, this study comprehensively revealed the pronounced species difference of the cleavage pathways: reductive ring-opening by intestinal microflora and liver, and amide hydrolysis.

Photocatalytic Synthesis of Diarylmethyl Silanes via 1,6-Conjugate Addition of Silyl Radicals to p-Quinone Methides.

A novel photocatalytic method for the preparation of diarylmethyl silanes was reported through silyl radicals addition strategy to p-QMs (p-quinone methides). This protocol could tolerate a variety of functional groups affording the corresponding silylation products with moderate to excellent yields. The resulting silylation products could be easily converted into a series of bioactive GPR40 agonists and useful p-QMs precursors for the synthesis of compounds possessing both quaternary carbon centers and silicon substituents through simple operation. A plausible mechanism of silyl radicals to p-QMs was proposed on the basis of experimental results and previous literature.

Synthesis and SAR of novel GPR39 agonists and positive allosteric modulators

We report a significant decrease in transcription of the G protein-coupled receptor GPR39 in striatal neurons of Parkinson’s disease patients compared to healthy controls, suggesting that a positive modulator of GPR39 may beneficially impact neuroprotection. To test this notion, we developed various structurally diverse tool molecules. While we elaborated on previously reported starting points, we also performed an in silico screen which led to completely novel pharmacophores. In vitro studies indicated that GPR39 agonism does not have a profound effect on neuroprotection.

Wet copper-slag: A new and eco-friendly catalyst for Knoevenagel condensation

This work describes a first-ever use of Wet copper-slag for efficient Knoevenagel condensation. Copper-slag is produced as a byproduct of the copper refining and smelting processes utilized as a basic catalyst in the present work. Natural Copper-slag was converted to Wet copper-slag by immersing it in water to improve the hydroxyl group and hence basicity. Various aldehyde and ketones reacted well with active methylenes in a shorter reaction time in environmentally-friendly ethanol: water (1:1) as solvent at room temperature/90 °C. The present method showed critical advantages of mild reaction conditions, wide availability, recyclability, and magnetic separability of a catalyst with higher product yields. The current protocol was also applied to synthesize the intermediate of AMG 837, a novel GPR40 agonist.