Optimization of Peptide Linker-Based Fluorescent Ligands for the Histamine H1 Receptor

J Med Chem. 2022 Jun 23;65(12):8258-8288. doi: 10.1021/acs.jmedchem.2c00125. Epub 2022 Jun 3.

Abstract

The histamine H1 receptor (H1R) has recently been implicated in mediating cell proliferation and cancer progression; therefore, high-affinity H1R-selective fluorescent ligands are desirable tools for further investigation of this behavior in vitro and in vivo. We previously reported a H1R fluorescent ligand, bearing a peptide-linker, based on antagonist VUF13816 and sought to further explore structure-activity relationships (SARs) around the linker, orthostere, and fluorescent moieties. Here, we report a series of high-affinity H1R fluorescent ligands varying in peptide linker composition, orthosteric targeting moiety, and fluorophore. Incorporation of a boron-dipyrromethene (BODIPY) 630/650-based fluorophore conferred high binding affinity to our H1R fluorescent ligands, remarkably overriding the linker SAR observed in corresponding unlabeled congeners. Compound 31a, both potent and subtype-selective, enabled H1R visualization using confocal microscopy at a concentration of 10 nM. Molecular docking of 31a with the human H1R predicts that the optimized peptide linker makes interactions with key residues in the receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fluorescent Dyes / metabolism
  • Histamine*
  • Humans
  • Ligands
  • Molecular Docking Simulation
  • Peptides
  • Receptors, Histamine / metabolism
  • Receptors, Histamine H1* / metabolism

Substances

  • Fluorescent Dyes
  • Ligands
  • Peptides
  • Receptors, Histamine
  • Receptors, Histamine H1
  • Histamine