Discovery of Novel Small Molecule Dual Inhibitors Targeting Toll-Like Receptors 7 and 8

J Med Chem. 2019 Nov 27;62(22):10221-10244. doi: 10.1021/acs.jmedchem.9b01201. Epub 2019 Nov 18.

Abstract

Endosomal toll-like receptors (TLRs) 7 and 8 recognize viral single-stranded RNAs, a class of imidazoquinoline compounds, 8-oxo-adenosines, 8-aminobenzodiazepines, pyrimidines, and guanosine analogues. Substantial evidence is present linking chronic inflammation mediated specifically by TLR7 to the progression of autoimmunity. We identified a new TLR7/8 dual inhibitor (1) and a TLR8-specific inhibitor (2) based on our previous screen targeting TLR8. Compound 1, bearing a benzanilide scaffold, was found to inhibit TLR7 and TLR8 at low micromolar concentrations. We envisioned making modifications on the benzanilide scaffold of 1 resulting in a class of highly specific TLR7 inhibitors. Our efforts led to the discovery of a new TLR8 inhibitor (CU-115) and identification of a TLR7/8 dual inhibitor (CU-72), bearing a distinct diphenyl ether skeleton, with potential for TLR7 selectivity optimization. Given the role of TLR8 in autoimmunity, we also optimized the potency of 2 and developed a new TLR8 inhibitor bearing a 1,3,4-oxadiazole motif.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anilides / chemistry
  • Animals
  • Crystallography, X-Ray
  • Dose-Response Relationship, Drug
  • Endosomes / drug effects
  • HEK293 Cells
  • High-Throughput Screening Assays / methods
  • Humans
  • Mice
  • Molecular Targeted Therapy
  • Oxadiazoles / chemistry
  • RAW 264.7 Cells
  • Reproducibility of Results
  • Small Molecule Libraries / chemistry*
  • Small Molecule Libraries / pharmacology*
  • Structure-Activity Relationship
  • Toll-Like Receptor 7 / antagonists & inhibitors*
  • Toll-Like Receptor 8 / antagonists & inhibitors*

Substances

  • Anilides
  • Oxadiazoles
  • Small Molecule Libraries
  • TLR7 protein, human
  • TLR8 protein, human
  • Toll-Like Receptor 7
  • Toll-Like Receptor 8
  • benzanilide