2. Academic Validation
  3. Development of Fluorescent AF64394 Analogues Enables Real-Time Binding Studies for the Orphan Class A GPCR GPR3

Development of Fluorescent AF64394 Analogues Enables Real-Time Binding Studies for the Orphan Class A GPCR GPR3

  • J Med Chem. 2023 Oct 31. doi: 10.1021/acs.jmedchem.3c01707.
Merlin Bresinsky 1,  Aida Shahraki 2,  Peter Kolb 2,  Steffen Pockes 1 3,  Hannes Schihada 2
Affiliations

Affiliations

  • 1 Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
  • 2 Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 8, 35032 Marburg, Germany.
  • 3 Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States.
PMID: 37907069 DOI: 10.1021/acs.jmedchem.3c01707
Abstract

The orphan G protein-coupled receptor (oGPCR) GPR3 represents a potential drug target for the treatment of Alzheimer's disease and metabolic disorders. However, the limited toolbox of pharmacological assays hampers the development of advanced ligands. Here, we developed a signaling pathway-independent readout of compound-GPR3 interaction. Starting from computational binding pose predictions of the most potent GPR3 ligand, we designed a series of fluorescent AF64394 analogues and assessed their suitability for BRET-based binding studies. The most potent ligand, 45 (UR-MB-355), bound to GPR3 and closely related receptors, GPR6 and GPR12, with similar submicromolar affinities. Furthermore, we found that 45 engages GPR3 in a distinct mode compared to AF64394, and coincubation studies with the GPR3 agonist diphenyleneiodonium chloride revealed allosteric modulation of 45 binding. These insights provide new cues for the pharmacological manipulation of GPR3 activity. This novel binding assay will foster the development of future drugs acting through these pharmacologically attractive oGPCRs.

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