Molecular determinants for nuclear receptors selectivity: chemometric analysis, dockings and site-directed mutagenesis of dual peroxisome proliferator-activated receptors alpha/gamma agonists

A series of previously synthesized chiral derivatives of clofibric and phenylacetic acids, acting as dual agonists towards the peroxisome proliferator-activated receptors (PPARs) alpha and gamma, was taken into account, and the efficacy of these compounds was analyzed by means of 2D-, 3D-QSAR and docking studies with the goal to gain deeper insights into the three-dimensional determinants governing ligands selectivity for PPARs. By multiregressional analysis a correlation between the lipophilicity and PPARalpha activity was found, whereas for PPARgamma the correlation was achieved once efficacy was related to the presence of polar groups on agonists scaffold. Docking of these compounds further corroborated this hypothesis, and then provided a valid support for subsequent chemometric analysis and pharmacophore models development for both receptors subtypes. Computational results suggested site directed mutagenesis experiments which confirmed the importance of amino acid residues in PPAR activity, allowing the identification of critical hotspots most likely taking over PPARs selectivity.