Purinergic P2X7 receptor mediates hyperoxia-induced injury in pulmonary microvascular endothelial cells via NLRP3-mediated pyroptotic pathway.

Background: Hyperoxia-induced injury is a well-recognized cause of bronchopulmonary dysplasia (BPD). Existing research studies have not well elucidated the exact mechanisms underlying hyperoxia-induced cellular damage. This study examines the involvement of the P2X7 receptor (P2X7R) in hyperoxia-induced damage to human pulmonary microvascular endothelial cells (HPMVECs) via the NOD-like receptor family, pyrin domain-containing protein 3 (NLRP3) pathway.

Methods: HPMVECs developing hyperoxia-induced injury were subjected to the treatment of either selective inhibitors or a P2X7R/NLRP3 agonist. Western blot analysis assisted in the quantification of the levels of P2X7R, NLRP3, caspase-1, and gasdermin D (GSDMD). Additionally, the release of TNF-α, IL-1β, and IL-18 was assessed by ELISA and qRT-PCR.

Results: Exposure to hyperoxia diminished cell viability and escalated the levels of P2X7R, caspase-1, NLRP3, GSDMD, and N-terminal-GSDMD. This exposure notably increased the release of TNF-α, IL-1β, and IL-18 in HPMVECs. Notably, the suppression of P2X7R using the inhibitor A438079 decreased pyroptosis and inflammatory responses. Conversely, stimulation of P2X7R by 3'-O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzATP) triggered pyroptosis, while inhibition of NLRP3 with glibenclamide ameliorated the damage induced by BzATP.

Conclusions: The P2X7R/NLRP3 pathway crucially affects the hyperoxia-induced inflammation and pyroptosis in HPMVECs, hinting the potential of blocking P2X7R/NLRP3-mediated pyroptotic pathway as a valuable therapeutic strategy for BPD.