Structure-activity relationships of fatty acid amide ligands in activating and desensitizing G protein-coupled receptor 119

Abstract

The purpose of the current study was to apply a high throughput assay to investigate the structure-activity relationships of fatty acid amides for activating and desensitizing G protein-coupled receptor 119, a promising therapeutic target for both type 2 diabetes and obesity. A cell-based, homogenous time resolved fluorescence (HTRF) method for measuring G protein-coupled receptor 119-mediated increase of cyclic adenosine monophosphate (cAMP) levels was validated and applied in this study. Using novel fatty acid amides and detailed potency and efficacy analyses, we have demonstrated that degree of saturation in acyl chain and charged head groups of fatty acid amides have profound effects on the ability of these compounds to activate G protein-coupled receptor 119. In addition, we have demonstrated for the first time that pretreatments with G protein-coupled receptor 119 agonists desensitize the receptor and the degrees of desensitization caused by fatty acid amides correlate well with their structure-activity relationships in activating the receptor.

Sustained wash-resistant receptor activation responses of GPR119 agonists

“…Additionally, the kinetics of the calcium response and levels of receptor reserve may also contribute to the observed differences in desensitization profile between these systems. A second recent report suggested that both AR-231,453 and oleoylethanolamide evoke complete desensitization of GPR119 cAMP responses (Kumar et al, 2014). However, in these experiments the investigators did not appear to wash out excess ligand before challenging with a second stimulus, which may preclude the observation of re-stimulation responses and therefore confound the observation of true desensitization.…”

“…Functionally, the consequences of this mechanism have been defined as sustained receptor activation even after removal of excess agonist (Calebiro et al, 2009;Ferrandon et al, 2009;Haskell-Luevano et al, 1996;Mullershausen et al, 2009). Whilst some evidence for GPR119 desensitization has been previously reported (Kumar et al, 2014;Lauffer et al, 2009;Zhang et al, 2014), a comprehensive characterization of desensitization of GPR119 cAMP signalling has not yet been conducted. This key gap in our understanding of GPR119 biology may be especially pertinent to observations of tachyphylaxis and lack of efficacy of GPR119 agonists in the clinic (Kang, 2013).…”

A categorical structure–activity relationship analysis of GPR119 ligands

“…These 14 known GPR119 agonists were selected from patents and literature sources (see Supplementary material). The 31 inactive compounds consisted of compounds which do act as agonists for GPR119 at concentrations up to 10 µM, which we experimentally confirmed using our established HTRF assay [16]. These inactive chemicals consisted of compounds originating from three distinct chemical libraries (FDA, NIH clinical collection, Tocriscreen) ensuring structural diversity (see Supplementary material).…”

“…The inactive data set (See Supplementary Material) consisted of compounds determined not to activate GPR119 (less than 10 % of AR231453 activity) at a concentration of 10 µM. Previously, we have validated a high throughput cAMP assay for screening GPR119 ligands [16]. Using this assay, in the current study, we experimentally tested the compounds in three commercially available libraries (FDA-approved drug library, NIH clinical collection, and Tocriscreen) as potential GPR119 agonists.…”

Cytotoxic and multidrug resistance reversal activities of novel 1,4-dihydropyridines against human cancer cells

“…SAR studies are of utmost importance for drug discovery in order to determine the important structural features required for higher pharmacological activities (Kumar et al, 2014;Singhuber et al, 2011).…”