Identification of a non peptidic RANTES antagonist

Area of Science:

• Immunology
• Pharmacology

Background:

• Chemokines like RANTES play a role in inflammatory and immune responses.
• THP-1 cells are a human monocytic cell line often used in immunological research.

Purpose of the Study:

• To identify novel compounds that inhibit RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) binding to its cellular receptors.
• To evaluate the functional effects of identified compounds on RANTES-mediated cellular responses.

Main Methods:

• Screening of a phenothiazine library for inhibition of radiolabeled RANTES binding to THP-1 cell membranes.
• Testing the specificity of inhibition against MCP-1 (Monocyte Chemoattractant Protein-1).
• Assessing the antagonistic activity of lead compounds on RANTES-induced chemotaxis of THP-1 cells.

Main Results:

• A series of phenothiazines were found to inhibit RANTES binding.
• The lead compound, RP23618, demonstrated significant inhibition of 125I-RANTES binding (IC50 = 3 microM) but not 125I-MCP-1 binding.
• RP23618 antagonized RANTES-induced chemotaxis of THP-1 cells, while having no effect on MCP-1-induced chemotaxis.

Conclusions:

• Phenothiazines represent a promising class of compounds for inhibiting RANTES-mediated cellular processes.
• RP23618 is a potent antagonist of RANTES binding and function, suggesting its potential therapeutic value in RANTES-driven inflammatory conditions.