Frontal Affinity Chromatography-Mass Spectrometry Useful for Characterization of New Ligands for GPR17 Receptor

The application of frontal affinity chromatography-mass spectrometry (FAC-MS), along with
molecular modeling studies, to the screening of potential drug candidates toward the recently
deorphanized G-protein-coupled receptor (GPCR) GPR17 is shown. GPR17 is dually activated by
uracil nucleotides and cysteinyl-leukotrienes, and is expressed in organs typically undergoing ischemic
damage (i.e., brain, heart and kidney), thus representing a new pharmacological target for acute and
chronic neurodegeneration. GPR17 was entrapped on an immobilized artificial membrane (IAM), and
this stationary phase was used to screen a library of nucleotide derivatives by FAC-MS to select high
affinity ligands. The chromatographic results have been validated with a reference functional assay
([35S]GTPγS binding assay). The receptor nucleotide-binding site was studied by setting up a column
where a mutated GPR17 receptor (Arg255Ile) has been immobilized. The chromatographic behavior of
the tested nucleotide derivatives together with in silico studies have been used to gain insights into the
structure requirement of GPR17 ligands.