(869) CD39 restrains ATP–P2X7-driven inflammatory cell death and neuroinflammation during neonatal Zika virus infection

Introduction/Rationale: Zika virus (ZIKV) can cause congenital Zika syndrome (CZS), marked by neuroinflammation and neurodevelopmental damage. Viral infection promotes extracellular ATP (eATP) release, acting as an alarmin that amplifies inflammation via purinergic receptors such as P2X7. CD39 enzyme (ENTPD1) hydrolyzes eATP and may restrain P2X7-dependent inflammatory cell death, but its role in neonatal ZIKV infection remains unclear.

Methods: THP-1-derived macrophages were stimulated with ZIKV or ZIKV envelope protein (ZIKV-E). Inflammatory readouts and eATP release were assessed, including evaluations with soluble apyrase or Axl-antagonist bemcentinib (R428). In vivo, WT and CD39⁻/⁻ pups were inoculated with ZIKV at postnatal day 3; brains were collected 12 days post-infection for molecular and histological analyses. Key pathways were also tested in P2X7⁻/⁻ mice.

Results: ZIKV-E increased eATP release and inflammatory responses, increased LDH release with elevated IL-1β/IL-6 and caspase-1/GSDMD-associated pyroptotic signaling; partially attenuated by soluble apyrase. R428 reduced ZIKV-E-induced eATP release, supporting upstream TAM/AXL involvement in purinergic activation. In neonatal brains, ZIKV upregulated CD39 transcripts and CD39 deficiency worsened motor performance and enhanced glial reactivity. CD39⁻/⁻ infection increased ZBP1 and apoptotic/pyroptotic markers (caspase-8, caspase-3, caspase-1, GSDMD), with enhanced association of ZBP1/caspase-3 with glial markers. CD39 deficiency enhanced IFN-β/STAT1 signaling. Conversely, P2X7 deficiency attenuated ZIKV-induced activation of apoptosis/pyroptosis markers, counterbalancing the CD39⁻/⁻ phenotype.

Conclusion: Our data identify CD39 as an upstream brake on eATP signaling that limits P2X7-linked inflammatory cell death and neuroinflammation during neonatal ZIKV infection, while shaping antiviral IFN responses. Targeting the CD39–P2X7 axis may provide therapeutic opportunities to mitigate neuroinflammatory damage in neurotropic viral infections.