Identification of potent pyrazole based APELIN receptor (APJ) agonists

Bioorg Med Chem. 2020 Feb 15;28(4):115237. doi: 10.1016/j.bmc.2019.115237. Epub 2019 Nov 30.


The apelinergic system comprises the apelin receptor and its cognate apelin and elabela peptide ligands of various lengths. This system has become an increasingly attractive target for pulmonary and cardiometabolic diseases. Small molecule regulators of this receptor with good drug-like properties are needed. Recently, we discovered a novel pyrazole based small molecule agonist 8 of the apelin receptor (EC50 = 21.5 µM, Ki = 5.2 µM) through focused screening which was further optimized to initial lead 9 (EC50 = 0.800 µM, Ki = 1.3 µM). In our efforts to synthesize more potent agonists and to explore the structural features important for apelin receptor agonism, we carried out structural modifications at N1 of the pyrazole core as well as the amino acid side-chain of 9. Systematic modifications at these two positions provided potent small molecule agonists exhibiting EC50 values of <100 nM. Recruitment of β-arrestin as a measure of desensitization potential of select compounds was also investigated. Functional selectivity was a feature of several compounds with a bias towards calcium mobilization over β-arrestin recruitment. These compounds may be suitable as tools for in vivo studies of apelin receptor function.

Keywords: AGTRL1; APLNR; Agonist; Apelin; Pyrazole; apelin receptor.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apelin Receptors / agonists*
  • Apelin Receptors / metabolism
  • CHO Cells
  • Cricetulus
  • Dose-Response Relationship, Drug
  • Humans
  • Microsomes, Liver / chemistry
  • Microsomes, Liver / metabolism
  • Molecular Structure
  • Pyrazoles / chemical synthesis
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacology*
  • Structure-Activity Relationship


  • APLNR protein, human
  • Apelin Receptors
  • Pyrazoles
  • pyrazole