Selective P2X4R agonist and antagonist ligands for theranostic modulation of neuroinflammation in alzheimer's disease and multiple sclerosis

Overview

This program targets the P2X4 receptor (P2X4R), a key regulator of microglial activity, to develop selective agonist and antagonist ligands that modulate neuroinflammation in Alzheimer's disease (AD) and multiple sclerosis (MS). P2X4R plays a dual role depending on disease context: in MS models, its activation promotes remyelination by enhancing phagocytosis of myelin debris, while in AD models, its inhibition reduces amyloid-beta burden and improves cognitive outcomes. The approach integrates ligand discovery, pharmacological validation, and radiolabelling for PET imaging, enabling both therapeutic intervention and real-time monitoring of target engagement.

Technical specifications

Core capabilities:

• Functional in vitro assay using ATP-induced calcium release in P2X4R-transfected HEK293 cells to characterize ligand activity
• Access to an 80,000-molecule chemical library through partnership in The French National Chemical Library
• Existing proprietary library of 36 P2X4R ligands with confirmed antagonist candidates showing higher affinity than benchmark compounds such as 5-BDBD
• In silico pharmacomodulation modelling for iterative ligand optimization
• Binding assays on human cell membranes and rat brain tissue
• Efficacy testing in P2X4R-expressing HEK293 and BV2 microglial cell lines
• Plasma and tissue pharmacokinetic and pharmacodynamic profiling by mass spectrometry to confirm brain availability
• In vivo validation in mouse models of MS (experimental autoimmune encephalomyelitis) and AD (APPswe × PSEN1dE9)
• Radiolabelling of lead ligands with fluorine-18 for PET imaging to quantify target engagement and microglial P2X4R expression in vivo, with [18F]DPA-714 as a fallback for neuroinflammation imaging

Technology readiness level

The program is at an early-to-mid preclinical stage. Core assay infrastructure, a curated ligand library, and medicinal chemistry workflows are already established, with initial hits already identified. Ongoing work includes in vitro and in vivo screening of expanded ligand sets, pharmacokinetic characterization, and efficacy testing in validated disease models. Radiolabelling and PET imaging validation are planned as the final preclinical steps prior to translational development.