Synthesis and Pharmacological Evaluation of Novel Non-nucleotide Purine Derivatives as P2X7 Antagonists for the Treatment of Neuroinflammation

• Published in: Journal of medicinal chemistry 2021-02, Vol.64 (4), p.2272-2290
• Main Authors: Calzaferri, Francesco, Narros-Fernández, Paloma, de Pascual, Ricardo, de Diego, Antonio M.G, Nicke, Annette, Egea, Javier, García, Antonio G, de los Ríos, Cristóbal
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases - metabolism; Animals; Anti-Inflammatory Agents - chemical synthesis; Anti-Inflammatory Agents - metabolism; Anti-Inflammatory Agents - pharmacology; ATP Binding Cassette Transporter, Subfamily B, Member 1 - metabolism; HEK293 Cells; Humans; Interleukin-1beta - metabolism; Macrophages, Peritoneal - drug effects; Male; Mice; Mice, Inbred C57BL; Molecular Docking Simulation; Oocytes - drug effects; Purinergic P2X Receptor Antagonists - chemical synthesis; Purinergic P2X Receptor Antagonists - metabolism; Purinergic P2X Receptor Antagonists - pharmacology; Purines - chemical synthesis; Purines - metabolism; Purines - pharmacology; Receptors, Purinergic P2X7 - metabolism; Xenopus laevis
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/acs.jmedchem.0c02145

The ATP-gated P2X7 purinergic receptor (P2X7) is involved in the pathogenesis of many neurodegenerative diseases (NDDs). Several P2X7 antagonists have been developed, though none of them reached clinical trials for this indication. In this work, we designed and synthesized novel blood–brain barrier (BBB)-permeable derivatives as potential P2X7 antagonists. They comprise purine or xanthine cores linked to an aryl group through different short spacers. Compounds were tested in YO-PRO-1 uptake assays and intracellular calcium dynamics in a human P2X7-expressing HEK293 cell line, two-electrode voltage-clamp recordings in Xenopus laevis oocytes, and in interleukin 1β release assays in mouse peritoneal macrophages. BBB permeability was assessed by parallel artificial membrane permeability assays and P-glycoprotein ATPase activity. Dichloroarylpurinylethanones featured a certain P2X7 blockade, being compound 6 (2-(6-chloro-9H-purin-9-yl)-1-(2,4-dichlorophenyl)­ethan-1-one), named ITH15004, the most potent, selective, and BBB-permeable antagonist. Compound 6 can be considered as a first non-nucleotide purine hit for future drug optimizations.