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The G-protein-coupled receptor 40 (GPR40) is an attractive molecular target for the treatment of type 2 diabetes mellitus. Previously, based on the natural oleic acid substrate, an exogenous ligand for this receptor, named AV1, was synthesized. In this context, here we validated the activity of AV1 as a full agonist, while the corresponding catechol analogue, named AV2, was investigated for the first time. The ligand-protein interaction between this new molecule and the receptor was highlighted in the lower portion of the GPR40 groove that generally accommodates DC260126. The functional assays performed have demonstrated that AV2 is a suitable GPR40 partial agonist, showing a therapeutic potential and representing a useful tool in the management of type 2 diabetes.

GPR40 (FFAR1 or FFA1) is a G protein-coupled receptor, primarily expressed in pancreatic islet β-cells and intestinal enteroendocrine cells. When activated by fatty acids, GPR40 elicits increased insulin secretion from islet β-cells only in the presence of elevated glucose levels. Towards this end, studies were undertaken towards discovering a novel GPR40 Agonist whose mode of action is via Positive Allosteric Modulation of the GPR40 receptor (AgoPAM). Efforts were made to identify a suitable GPR40 AgoPAM tool molecule to investigate mechanism of action and de-risk liver toxicity of GPR40 AgoPAMs due to reactive acyl-glucuronide (AG) metabolites.

The free fatty acid receptor 1 (FFA1) is considered as a promising anti-diabetic target based on its function of glucose-stimulated insulin secretion. The previously reported compound 2 is a highly potent FFA1 agonist, but it might be suffered from poor pharmacokinetic properties because the phenylpropanoic acid is vulnerable to β-oxidation. To identify orally available analogs, we tried to block the route of β-oxidation by incorporating deuterium at phenylpropionic acid moiety. As expected, the deuterium-based analogs 3 and 4 exhibited better pharmacokinetic properties than parent compound 2. Although the difference of potency between compound 2 and 3 is quite small, the glucose-lowering effect of deuterium analog 3 was better than that of compound 2. Meanwhile, compound 3 docked well into the same binding pocket of TAK-875, and formed almost identical interactions of TAK-875 in binding site. Different from glibenclamide, a lower risk of hypoglycemia was observed in compound 3 even at the high dose of 60 mg/kg.

Type-2 diabetes mellitus is a progressive cluster of metabolic disorders, representing a global public health burden affecting more than 366 million people worldwide. We recently reported the discovery of three series of novel agents showing balanced activity on two metabolic receptors, peroxisome proliferator activated receptor-γ (PPAR-γ) and free fatty acid receptor 1 (FFAR1), also known as GPCR40. Our designing strategy relied on linking the thiazolidinedione head with known GPCR privilege structures. To further investigate this concept, two new scaffolds, the benzhydrol- and indole-based chemotypes, were introduced here in. Our optimization campaign resulted in three compounds; 15a, 15c, and 15d, with affinities in the low micromolar range on both targets. In vivo study of selected test compounds, revealed that 15c possesses a significant anti-hyperglycemic and anti-hyperlipidemic activities superior to rosiglitazone in fat-fed animal models. Molecular docking analysis was conducted to explain the binding modes of both series. These compounds could lead to the development of the unique antidiabetic agent acting as insulin sensitizer as well as insulin secretagogue.

The discovery of a novel series of N-arylpyrroles as agonists of GPR120 (FFAR4) is discussed. One lead compound is a potent GPR120 agonist, has good selectivity for related receptor GPR40 (FFAR1), has acceptable PK properties, and is active in 2 models of Type 2 Diabetes in mice.

Compound 12 is a GPR40 agonist that realizes the full magnitude of efficacy possible via GPR40 receptor agonism. In vitro and in vivo studies demonstrated superior glucose lowering by 12 compared to fasiglifam (TAK-875), in a glucose dependent manner. The enhanced efficacy observed with the full agonist 12 was associated with both direct and indirect stimulation of insulin secretion.

The progress made so far in the elucidation of the structure of free fatty acid receptor 1 (FFAR1) and its secondary and ternary complexes with partial and full allosteric ligands led to the discovery of various putative binding regions on the FFAR1 surface. Attempts to develop FFAR1 agonists culminated with the identification of TAK-875 (1), whose phase 3 clinical trials were terminated due to potential liver toxicity. In the search of safer agonists, numerous classes of new compounds were designed, synthesized, and tested. Chemical decoration of the scaffolds was rationalized to reach a good balance between lipophilicity, activity, and toxicity. Today, targeting FFAR1 with positive modulators represents an attractive pharmacological tool for the treatment of type 2 diabetes mellitus (T2DM), mainly because of the lack of hypoglycaemic side effects associated with several antidiabetic drugs currently available. Moreover, considering the involvement of FFAR1 in many physio-pathological processes, its agonists are also emerging as possible therapeutic tools for alleviating organ inflammation and fibrosis, as well as for the treatment of CNS disorders, such as Alzheimer's disease and dementia.

GPR40 belongs to the GPCR family and the activation of GPR40 has been shown to induce glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells as well as incretin secretion from intestinal endocrine cells. Therefore, GPR40 has emerged as a viable and promising therapeutic target for type 2 diabetes mellitus (T2DM) without the risk of hypoglycemia. However, the termination of TAK-875 in phase III clinical trials for the hepatotoxicity issue threw doubt over the long-term safety of targeting GPR40. Herein, we summarized the newly disclosed biological characteristics and the druglikeness-based structural evolution of GPR40 agonists to advance the development of GPR40-based anti-diabetic drugs.

As a follow-up to the GPR40 agonist AMG 837, which was evaluated in clinical trials for the treatment of type II diabetes, further optimization led to the discovery of AM-3189 (13k). AM-3189 is representative of a new class of compounds with minimal CNS penetration, superior pharmacokinetic properties and in vivo efficacy comparable to AMG 837.

A screening hit that showed a weak (EC50 = 18 μM), partial agonistic effect on GPR40 was used a prototype for expedited hit expansion effort using a set of advanced building blocks. The latter yielded several 1,3-oxazoles and 1,2,4-oxadiazoles with significantly improved potency (best EC50 = 0.058 μM). The lead compounds in each chemotype showed a very good ADME profile (aqueous solubility, plasma protein binding, microsomal stability and membrane permeability) and no appreciable inhibition of key cytochromes P450. The compounds reported are significant new starting points for further preclinical development of future diabetic agents with a mechanism of action for which a first-in-class agent is yet to be approved.

Despite the availability of established medication for treatment of type 2 diabetes mellitus (T2DM) there still remains a significant unmet need for new effective, oral antidiabetic agents that improve glycemic control while maintaining an excellent safety profile. In this regard the FFA1 receptor has emerged as an attractive target in recent years. Activation of the FFA1 receptor has been shown to not only amplify glucose induced insulin secretion from pancreatic beta cells but also to stimulate incretin secretion from intestinal endocrine cells. The current review highlights on the latest developments and clinical data from evolving research on the potential of FFA1 agonists as effective treatment for T2DM.

The GPR40 (FFA1) has emerged as an attractive target for a novel insulin secretagogue with glucose dependency. A series of novel orally bioavailable GPR40 agonists was discovered. SAR study and structural optimization led to identification of compounds 28a and 30a as potent GPR40 agonists with superior physiochemical properties and robust in vivo efficacy in rhesus monkeys.

The discovery that certain long chain fatty acids potentiate glucose stimulated insulin secretion through the previously orphan receptor GPR40 sparked interest in GPR40 agonists as potential antidiabetic agents. Optimization of a series of β-substituted phenylpropanoic acids led to the identification of (S)-3-(4-((4'-(trifluoromethyl)biphenyl-3-yl)methoxy)phenyl)hex-4-ynoic acid (AMG 837) as a potent GPR40 agonist with a superior pharmacokinetic profile and robust glucose-dependent stimulation of insulin secretion in rodents.

Systematic structure-activity relationship (SAR) studies of a screening lead led to the discovery of a series of thiazolidinediones (TZDs) as potent GPR40 agonists. Among them, compound C demonstrated an acute mechanism-based glucose-lowering in an intraperitoneal glucose tolerance test (IPGTT) in lean mice, while no effects were observed in GPR40 knock-out mice.

The development of a series of novel 1,2,3,4-tetrahydroisoquinolin-1-ones as antagonists of G protein-coupled receptor 40 (GPR40) is described. The synthesis, in vitro inhibitory values for GPR40, in vitro microsomal clearance and rat in vivo clearance data are discussed. Initial hits displayed high rat in vivo clearances that were higher than liver blood flow. Optimization of rat in vivo clearance was achieved and led to the identification of 15i, whose rat oral pharmacokinetic data is reported.

In this letter, we report discovery of diacylphloroglucinol compounds as a new class of GPR40 (FFAR1) agonists. Several diacylphloroglucinols with varying length of acyl functionality and substitution on aromatic hydroxyls were synthesized and evaluated for GPR40 agonism using functional calcium-flux assay. Out of 17 compounds evaluated, 14, 17, 19 and 25 exhibited good GPR40 agonistic activity with EC(50) values ranging from 0.07 to 8 microM (pEC(50) 7.12-5.09), respectively, with maximal agonistic response of 84-102%.

The discovery, synthesis and structure-activity relationship (SAR) of novel carboxylic acid agonists for GPR40 are described. Aryl propionic acid 1, identified from a high throughput screen, was selected for chemical exploration. Compound 2 was identified as our lead molecule through efficient solid phase combinatorial array chemistry and had an attractive in vitro and in vivo pharmacokinetic profile in rat. These ligands may prove useful in establishing a role for GPR40 in insulin regulation.