Identification of Novel GPR55 Modulators Using Cell-Impedance-Based Label-Free Technology

J Med Chem. 2016 Mar 10;59(5):1840-53. doi: 10.1021/acs.jmedchem.5b01331. Epub 2016 Feb 5.

Abstract

The orphan G protein-coupled receptor GPR55 has been proposed as a novel receptor of the endocannabinoid system. However, the validity of this categorization is still under debate mainly because of the lack of potent and selective agonists and antagonists of GPR55. Binding assays are not yet available for GPR55 screening, and discrepancies in GPR55 mediated signaling pathways have been reported. In this context, we have designed and synthesized novel GPR55 ligands based on a chromenopyrazole scaffold. Appraisal of GPR55 activity was accomplished using a label-free cell-impedance-based assay in hGPR55-HEK293 cells. The real-time impedance responses provided an integrative assessment of the cellular consequence to GPR55 stimulation taking into account the different possible signaling pathways. Potent GPR55 partial agonists (14b, 18b, 19b, 20b, and 21-24) have been identified; one of them (14b) being selective versus classical cannabinoid receptors. Upon antagonist treatment, chromenopyrazoles 21-24 inhibited lysophosphatidylinositol (LPI) effect. One of these GPR55 antagonists (21) is fully selective versus classic cannabinoid receptors. Compared to LPI, the predicted physicochemical parameters of the new compounds suggest a clear pharmacokinetic improvement.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dose-Response Relationship, Drug
  • Electric Impedance
  • Enzyme Assays / methods*
  • HEK293 Cells
  • Humans
  • Molecular Structure
  • Pyrazoles / chemical synthesis
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacology*
  • Receptors, Cannabinoid
  • Receptors, G-Protein-Coupled / antagonists & inhibitors*
  • Receptors, G-Protein-Coupled / metabolism*
  • Signal Transduction / drug effects
  • Structure-Activity Relationship

Substances

  • GPR55 protein, human
  • Pyrazoles
  • Receptors, Cannabinoid
  • Receptors, G-Protein-Coupled