RRS1 regulates proliferation, migration, and invasion of HTR-8/SVneo human trophoblasts

Trophoblast cells serve as the foundation for placental development. We analyzed published multiomics sequencing data and found that trophoblast cells highly expressed RRS1 compared to primitive endoderm and epiblast. We used HTR-8/SVneo cells for further investigation, and Western blot and immunofluorescence staining confirmed that HTR-8/SVneo cells highly expressed RRS1. RRS1 was successfully knocked down in HTR-8/SVneo cells using siRNA. Using IncuCyte S3 live-cell analysis system based on continuous live-cell imaging and real-time data, we observed that proliferation, migration, and invasion abilities were all significantly decreased in RRS1-knockdown cells. RNA-seq revealed that knockdown of RRS1 affected the gene transcription, and upregulated pathways in extracellular matrix organization, DNA damage response, and intrinsic apoptotic signaling, downregulated pathways in embryo implantation, trophoblast cell migration, and wound healing. Differentially expressed genes were enriched in diseases related to placental development. Consistent with these findings, human chorionic villus samples collected from spontaneous abortion cases exhibited significantly reduced RRS1 expression compared to normal controls. Our results highlight the functional importance of RRS1 in human trophoblasts and suggest that its deficiency contributes to early pregnancy loss.