The Synergistic Role of P2rx7 and Panx1 in Regulating Alveolar Macrophage Pyroptosis and Exosome-Mediated Ferroptosis of Alveolar Epithelial Cells in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) represents a severe pulmonary condition characterized by widespread alveolar injury and inflammatory cascade activation. While alveolar macrophages and epithelial cells are recognized as critical mediators in ARDS pathogenesis, the molecular mechanisms underlying their dysfunction remain incompletely understood. This study investigated the regulatory role of the P2rx7-Panx1 signaling axis in orchestrating alveolar macrophage pyroptosis and subsequent exosome-mediated ferroptosis of alveolar epithelial cells in lipopolysaccharide (LPS)-induced ARDS. The study utilized both an in vivo ARDS mouse model and in vitro systems comprising MH-S alveolar macrophages and MLE-12 alveolar epithelial cells. P2rx7-Panx1 interaction was characterized through Western blot analysis, immunofluorescence microscopy, and co-immunoprecipitation studies. The functional consequences of P2rx7 and Panx1 depletion were assessed through comprehensive analyses of cell viability, inflammatory cytokine profiles, oxidative stress parameters, and protein expression patterns. LPS exposure induced significant upregulation and enhanced interaction of P2rx7 and Panx1 in alveolar macrophages both in vivo and in vitro. Selective knockdown of either P2rx7 or Panx1 significantly attenuated LPS-induced macrophage pyroptosis, as evidenced by reduced cell death, diminished NLRP3/ASC/caspase-1 activation, and decreased IL-1β/IL-18 secretion, with dual knockdown exhibiting synergistic protection. Furthermore, LPS-stimulated macrophages induced ferroptosis in alveolar epithelial cells through P2rx7-dependent exosome release, while P2rx7 blockade effectively prevented this exosome-mediated epithelial cell ferroptosis. This study elucidates a novel mechanism whereby the P2rx7-Panx1 axis synergistically regulates LPS-induced alveolar macrophage pyroptosis through caspase-11-dependent pathways. Moreover, P2rx7 functions as a critical modulator of exosome release from alveolar macrophages, thereby promoting ferroptotic death of alveolar epithelial cells. These findings identify the P2rx7-Panx1 signaling axis as a promising therapeutic target in ARDS treatment.