Eosinophils adhesion assay as a tool for phenotypic drug screening - The pharmacology of 1,3,5 - Triazine and 1H-indole like derivatives against the human histamine H4 receptor

Eur J Pharmacol. 2021 Jan 5:890:173611. doi: 10.1016/j.ejphar.2020.173611. Epub 2020 Oct 2.


Histamine is a pleiotropic biogenic amine, having affinity towards four distinct histamine receptors. The existing pharmacological studies suggest the usefulness of histamine H4 receptor ligands in the treatment of many inflammatory and immunomodulatory diseases, including allergic rhinitis, asthma, atopic dermatitis, colitis or pruritus. Up to date, several potent histamine H4 receptor ligands were developed, none of which was registered as a drug yet. In this study, a series of potent indole-like and triazine derivatives were tested, in radioligand displacement and functional assays at histamine H4 receptor, as well as in human eosinophils adhesion assay to endothelium. For selected compounds permeability, cytotoxicity, metabolic and in vivo studies were conducted. Adhesion assay differentiated the activity of different groups of compounds with a known affinity towards the histamine H4 receptor. Most of the tested compounds downregulated the number of adherent cells. However, adhesion assay revealed additional properties of tested compounds that had not been detected in radioligand displacement and aequorin-based functional assays. Furthermore, for some tested compounds, these abnormal effects were confirmed during the in vivo studies. In conclusion, eosinophils adhesion assay uncovered pharmacological activity of histamine H4 receptor ligands that has been later confirmed in vivo, underscoring the value of well-suited cell-based phenotypic screening approach in drug discovery.

Keywords: 1,3,5 – Triazine derivatives; 1H-Indole like derivatives; 1H-indole like derivatives; Adhesion; Endothelium; Eosinophils; Histamine; Histamine receptors; JN-25 (4-[(E)-2-(3-chlorophenyl)ethenyl]-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine); JN-35 (4-(4-methylpiperazin-1-yl)-6-(3-phenylpropyl)-1,3,5-triazin-2-amine); JNJ10191584 (5-chloro-1H-benzo[d]imidazol-2-yl)(4-methylpiperazin-1-yl)methanone) Pub- Chem CID: 10446295); JNJ7777120 (5-chloro-1H-indol-2-yl)(4-methylpiperazin-1-yl)methanone) Pub- Chem CID: 4908365); KP-9D (2-(4-chlorophenyl)-4-(4-methylpiperazin-1-yl)-1,3,5-triazine); MWJ-3 (5-chloro-7-nitro-1H-indol-2-yl)(4-methylpiperazin-1-yl)methanone Pub- Chem CID: 70692530); TR-18 (4-(4-bromophenyl)-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine); TR-7 (4-(4-chlorophenyl)-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine); TR-AF-45 (4-(4-methylpiperazin-1-yl)-6-neopentyl-1,3,5-triazin-2-amine); TR-AF-49 (4-(cyclohexylmethyl)-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine); TR-DL-20 (4-(1-cyclohexenylmethyl)-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine).

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / administration & dosage
  • Anti-Inflammatory Agents / metabolism
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Adhesion / drug effects
  • Cell Line, Transformed
  • Cell Line, Tumor
  • Cell Membrane Permeability / drug effects
  • Cell Survival / drug effects
  • Computer Simulation
  • Croton Oil / toxicity
  • Disease Models, Animal
  • Drug Discovery
  • Drug Evaluation, Preclinical
  • Edema / chemically induced
  • Edema / drug therapy
  • Endothelial Cells / metabolism
  • Eosinophils / drug effects
  • Eosinophils / metabolism*
  • Humans
  • Indoles / administration & dosage
  • Indoles / chemistry
  • Indoles / pharmacology*
  • Male
  • Mice
  • Pruritus / chemically induced
  • Pruritus / drug therapy
  • Receptors, Histamine H4 / antagonists & inhibitors*
  • Triazines / administration & dosage
  • Triazines / chemistry
  • Triazines / metabolism
  • Triazines / pharmacology*


  • Anti-Inflammatory Agents
  • HRH4 protein, human
  • Indoles
  • Receptors, Histamine H4
  • Triazines
  • Croton Oil