Pharmacological evaluation of novel non-nucleotide purine derivatives as
P2X7R antagonists for the treatment of neuroinflammation in traumatic
brain injury
Abstract
Background and purpose. Traumatic brain injury (TBI) is an acute brain
lesion considered as one of the leading causes of mortality and
disability worldwide. After TBI, innate immunity is rapidly activated in
response to damage-associated molecular patterns, such as ATP release,
recognized by P2X7 purinergic receptors (P2X7R). The P2X7R-NLRP3
inflammasome axis has been identified as one of the main actors in
neuroinflammation. Therefore, this study aimed to validate P2X7R as
therapeutic target in TBI. Experimental approach. P2X7R was validated
through genetic and pharmacological approaches. Six non-nucleotide
purine derivatives were evaluated as P2X7R antagonists. Compounds that
prevented LPS+ATP-induced IL-1β release from primary glial cultures were
investigated in the closed-head injury TBI model in vivo. Finally, we
evaluated sP2X7R plasmatic levels in a cohort of TBI patients. Key
results. p2x7 -/- mice showed an exaggerated inflammatory response 24 h
post-TBI compared to control mice. However, animals treated with the
selective P2X7R antagonist JNJ-47965567 (30 mg/kg i.p.) 30 min post-TBI
showed improved neurological and inflammatory parameters. The purine
derivative ITH15004 was the most potent compound reducing IL-1β
production in vitro. When administered in vivo 30 min post-TBI, ITH15004
(1 mg/kg i.p.) improved both neurobehavioral and inflammatory markers at
24 h. In TBI patients, enhanced levels of circulating sP2X7R correlated
with the lesion severity 72 h post-TBI and with unfavourable outcomes 24
h post-TBI. Conclusion and implications. These results highlight the
importance of P2X7R in the acute phase of TBI and present ITH15004 as a
new pharmacological tool to counteract P2X7R-dependent neuroinflammation
in vivo.