Aspirin protects trophoblast function against hypoxia-induced oxidative stress through activation of NRF2 signaling in preeclampsia

Preeclampsia (PE, a pregnancy-specific hypertensive disorder) is characterized by placental hypoxia, oxidative stress, metabolic dysfunction, and trophoblast impairment, yet effective disease-modifying therapies remain limited. Although low-dose aspirin (Acetylsalicylic acid, ASA) is recommended for the prevention of PE and has shown protective effects in pregnancy, the underlying placental mechanisms remain incompletely understood. Nuclear factor erythroid 2–related factor 2 (NRF2), a central regulator of cellular antioxidant defense, plays a critical role in counteracting oxidative stress, but its role in placental pathology and its contribution to ASA-mediated protection in PE have not been fully elucidated. In this study, placental tissues were collected from normotensive pregnancies and from patients with mild and severe PE, and relevant maternal clinical characteristics were recorded to contextualize findings. In parallel, trophoblast cells were exposed to physiological hypoxia or hydrogen peroxide (H₂O₂)–induced oxidative stress to mimic PE-relevant placental stress conditions, followed by ASA treatment. Trophoblast function, oxidative stress, and apoptosis were evaluated, and the involvement of NRF2 was examined using shRNA-mediated knockdown. Placental tissues from PE pregnancies, particularly those from severe cases, exhibited increased oxidative stress accompanied by dysregulated NRF2-dependent antioxidant signaling. In vitro, both hypoxia and oxidative stress significantly impaired trophoblast proliferation and invasion while increasing reactive oxygen species (ROS) accumulation and apoptosis. ASA treatment markedly reduced oxidative stress and improved trophoblast function under both stress conditions. Notably, genetic silencing of NRF2 largely abolished the antioxidative and cytoprotective effects of ASA. These findings indicate that ASA alleviates placental oxidative injury and trophoblast dysfunction, at least in part, through an NRF2-dependent mechanism, providing mechanistic insight into the placental protective effects of ASA in PE and highlighting the potential clinical relevance of ASA for high-risk pregnancies.