Astragaloside IV protects human trophoblast HTR8/SVneo cells from H2O2-Induced oxidative stress via Nrf2-Keap1-p62 feedback loop

Preeclampsia is one of the serious complications of pregnancy and is the main cause of maternal death. Accumulation of trophoblastic reactive oxygen species (ROS) and placental dysfunction are the potential pathogenic bases of early-onset preeclampsia. Astragaloside IV (AS IV), one of the major and active components of Astragalus membranaceus (Fisch.) Bunge, is known for its antioxidant effects in many diseases. This study aimed to investigate the protective effects and potential mechanisms of AS IV against oxidative stress-induced damage in trophoblasts. We established an oxidative stress in vitro model using an extravillous trophoblast cell line (HTR8/SVneo). The results demonstrated that pretreatment of HTR8/SVneo cells with AS IV can potently suppress the increase in ROS level and the cell apoptosis rate and rescue the H2O2-induced decrease in cell viability. Mechanistically, the antioxidant effects of AS IV were achieved by activating nuclear factor erythroid 2-related factor 2 (Nrf2), along with an increase in autophagy makers and a decrease in Keap1 levels. Silencing Nrf2 and p62 with siRNA dramatically abolished the prosurvival effects of AS IV on treated HTR8/SVneo cells. Further study results on the relationship among Nrf2, Keap1, and p62 by siRNAs showed that the Keap1/Nrf2 pathway and p62 form a positive feedback loop. Our present study demonstrated that AS IV protects human trophoblasts against H2O2-induced oxidative stress via the activation of the Nrf2-Keap1-p62 feedback loop. These findings provide a cue for future studies on the use of AS IV as a protective and curative agent against preeclampsia.