Downregulation of Pannexin-1 attenuates sepsis-induced acute lung injury via activation of the cAMP/PKA pathway.

Abstract

Sepsis-induced acute lung injury (ALI) is a severe complication with limited treatment options. Pannexin-1 (PANX1), a membrane channel involved in inflammatory signaling, has been implicated in various diseases, but its role in ALI remains unclear. This study aimed to investigate the contribution of PANX1 to ALI and its regulatory mechanisms. PANX1 expression was analyzed in blood samples from ALI patients and healthy controls, in a cecal ligation and puncture (CLP)-induced ALI rat model, and in lipopolysaccharide (LPS)-treated human pulmonary artery endothelial cells (HPAECs). PANX1 knockdown was achieved using shRNA both in vivo and in vitro. Lung tissue damage was assessed by histology, apoptosis by TUNEL and flow cytometry, proliferation by EdU and Ki67/PCNA immunostaining, and inflammatory cytokines by ELISA. Activation of the cAMP/PKA pathway was examined via Western blot and ELISA. The cAMP/PKA inhibitor H89 and KT5720 were used to confirm pathway involvement. PANX1 was significantly upregulated in ALI patients, CLP rats, and LPS-stimulated HPAECs. Silencing PANX1 alleviated lung injury, reduced apoptosis, promoted cell proliferation, and decreased levels of TNF-α, IL-1β, IL-6, and IFN-γ. Mechanistically, PANX1 downregulation activated the cAMP/PKA signaling pathway, an effect reversed by H89/KT5720 treatment, indicating its pivotal role in modulating inflammation. These findings suggest that PANX1 promotes sepsis-induced ALI by suppressing cAMP/PKA signaling and exacerbating inflammation. Targeting PANX1 may represent a promising therapeutic strategy for ALI.