AQP3-mediated H₂O₂ transport drives macrophage M1 polarization and cervical matrix remodeling in cervical insufficiency†.

Cervical insufficiency (CI) affects 0.1%-2% of pregnancies and represents a significant cause of second-trimester pregnancy loss and preterm birth; yet, its pathophysiology remains incompletely understood. This study investigated whether aquaporin-3 (AQP3) facilitates hydrogen peroxide (H₂O₂) transport into cervical macrophages, driving their polarization toward a pro-inflammatory phenotype and subsequent cervical matrix degradation. Cervical tissues from women with CI demonstrated 1.45-fold higher AQP3 expression compared to gestational age-matched controls, with increased colocalization with macrophages. Tissue H₂O₂ levels were elevated 2.43-fold in CI, accompanied by increased oxidative damage markers and reduced collagen content. In vitro studies using THP-1 macrophages revealed that AQP3 knockdown prevented intracellular H₂O₂ accumulation despite pro-inflammatory stimulation, blocking M1 polarization and NF-κB activation. Co-culture experiments demonstrated that AQP3-dependent M1 macrophages increased matrix metalloproteinase (MMP)-9 activity 3.8-fold and reduced fibroblast collagen content by 59%. Both H₂O₂ scavenging with PEG-catalase and NF-κB inhibition with Bay 11-7082 prevented macrophage-mediated matrix degradation. These findings suggest that AQP3 may serve as an important mediator linking oxidative stress to inflammatory cervical remodeling through facilitation of H₂O₂ influx, NF-κB activation, and M1 macrophage polarization. Targeting AQP3 or its downstream signaling may represent a potential therapeutic approach that requires preclinical validation to prevent CI-associated pregnancy complications.