SPI1 Transcriptional Activates TXNRD1 to Protect Trophoblast Cell from Ferroptosis

Preeclampsia (PE) is a severe complication of pregnancy characterized by hypertension and organ dysfunction. Abnormal low expression of thioredoxin reductase 1 (TXNRD1) in the placenta has been implicated in the pathogenesis of PE. This study aimed to investigate the role of TXNRD1 in PE and its association with ferroptosis. In our study, placental tissues collected from healthy pregnant women and PE patients, as well as trophoblast cell lines (HTR-8 and JEG-3) were employed in this study. QPCR, Western blot, and immunohistochemistry (IHC) were performed to detect the genes expression. Additionally, ferroptosis level was tested by assessing cell activity, reactive oxygen species (ROS) levels, lipid oxidation, and key ferroptosis-related proteins. The transcriptional regulation mechanism of TXNRD1 was explored using bioinformatics tools, dual luciferase reporter assay, ChIP-qPCR, and electrophoretic mobility shift assay (EMSA). Our results showed that TXNRD1 expression was significantly lower in the placenta of PE patients compared to healthy controls. Consistently, the protein levels of GPX4 and SLC7A11, which are inhibitors of ferroptosis, were reduced in PE, while the levels of COX2 and ACSL4, promoters of ferroptosis, was increased. Overexpression of TXNRD1 in trophoblast cells enhanced ferroptosis resistance, as evidenced by increased cell activity, reduced ROS levels, inhibited lipid oxidation, and altered expression of ferroptosis-related proteins. Conversely, knocking down TXNRD1 exacerbated erastin-induced ferroptosis. Furthermore, we identified SPI1 as a transcriptional activator of TXNRD1, which was also abnormally low expressed in the placenta of PE patients. Overexpression of SPI1 protected trophoblast cells from ferroptosis, which was reversed by inhibiting TXNRD1 expression. Collectively, our findings reveal that SPI1-mediated transcriptional regulation of TXNRD1 plays a protective role in ferroptosis of trophoblast cell, and impeded TXNRD1 expression might involve in PE, advancing our understanding of its pathogenesis.