RESUMEN
The design, synthesis and structure-activity relationships of a novel series of N-phenyl-substituted pyrrole, 1,2-pyrazole and 1,2,3-triazole acid analogs as PPAR ligands are outlined. The triazole acid analogs 3f and 4f were identified as potent dual PPARalpha/gamma agonists both in binding and functional assays in vitro. The 3-oxybenzyl triazole acetic acid analog 3f showed excellent glucose and triglyceride lowering in diabetic db/db mice.
Asunto(s)
Azoles/síntesis química , Diseño de Fármacos , PPAR alfa/agonistas , PPAR gamma/agonistas , Animales , Azoles/farmacología , Línea Celular/enzimología , Cristalografía por Rayos X , Femenino , Humanos , Concentración de Iones de Hidrógeno , Ratones , Ratones Transgénicos , PPAR alfa/metabolismo , PPAR gamma/metabolismo , Relación Estructura-ActividadRESUMEN
The human pregnane X receptor (PXR) is a promiscuous nuclear receptor that functions as a sensor to a wide variety of xenobiotics and regulates expression of several drug metabolizing enzymes and transporters. We have generated "Adnectins", derived from 10th fibronectin type III domain ((10)Fn3), that target the PXR ligand binding domain (LBD) interactions with the steroid receptor co-activator-1 (SRC-1) peptide, displacing SRC-1 binding. Adnectins are structurally homologous to the immunoglobulin superfamily. Three different co-crystal structures of PXR LBD with Adnectin-1 and CCR1 (CC chemokine receptor-1) antagonist Compound-1 were determined. This structural information was used to modulate PXR affinity for a related CCR1 antagonist compound that entered into clinical trials for rheumatoid arthritis. The structures of PXR with Adnectin-1 reveal specificity of Adnectin-1 in not only targeting the interface of the SRC-1 interactions but also engaging the same set of residues that are involved in binding of SRC-1 to PXR. Substituting SRC-1 with Adnectin-1 does not alter the binding conformation of Compound-1 in the ligand binding pocket. The structure also reveals the possibility of using Adnectins as crystallization chaperones to generate structures of PXR with compounds of interest.
Asunto(s)
Coactivador 1 de Receptor Nuclear/química , Receptores CCR1/antagonistas & inhibidores , Receptores de Esteroides/química , Urea/análogos & derivados , Valina/análogos & derivados , Secuencia de Aminoácidos , Sitios de Unión , Cristalografía por Rayos X , Humanos , Lignanos/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Receptor X de Pregnano , Unión Proteica , Estructura Terciaria de Proteína , Receptores CCR1/metabolismo , Alineación de Secuencia , Resonancia por Plasmón de Superficie , Urea/química , Urea/metabolismo , Urea/farmacología , Valina/química , Valina/metabolismo , Valina/farmacologíaRESUMEN
Pregnane X receptor (PXR) transactivation and binding assays have been developed into high-throughput assays, which are robust and reproducible (Z' > 0.5). For most compounds, there was a good correlation between the results of the transactivation and binding assays. EC(50) values of compounds in the transactivation assay correlated reasonably well with their IC(50) values in the binding assay. However, there were discrepancies with some compounds showing high binding affinity in the binding assay translated into low transactivation. The most likely cause for these discrepancies was an agonist-dependent relationship between binding affinity and transactivation response. In general, compounds that bound to human PXR and transactivated PXR tended to be large hydrophobic molecules.