MiRNA-494 induces trophoblast senescence by targeting SIRT1.

OBJECTIVE: Although the mechanism underlying preeclampsia (PE) has been widely explored, the mechanisms related to senescence have not yet been fully revealed. Therefore, we investigated the role of the miR-494/longevity protein Sirtuin 1 (SIRT1) axis in PE.

METHODS: Human placental tissue was obtained from severe preeclampsia (SPE) ( n  = 20) and gestational age-matched normotensive pregnancies ( n  = 20), and senescence-associated β-galactosidase (SAβG) and SIRT1 expression levels were measured. The TargetScan and miRDB databases predicted candidate miRNAs targeting SIRT1, and intersected with differentially expressed miRNAs in the GSE15789 dataset ( p  < 0.05, |log2 FC|≥1.5). Subsequently, we showed that miRNA (miR)-494 expression was significantly elevated in SPE, revealing miR-494 as a candidate SIRT1-binding miRNA. A dual-luciferase assay confirmed the targeting relationship between miR-494 and SIRT1. The senescence phenotype, migration, cell viability, reactive oxygen species (ROS) production levels and inflammatory molecule expression levels were measured after miR-494 expression was altered. We conducted a rescue experiment using SIRT1 plasmids to further demonstrate the regulatory relationship.

RESULTS: SIRT1 expression was lower( p  < 0.01) and miR-494 expression was higher ( p  < 0.001) in SPE, and SaβG staining showed premature placental aging in SPE ( p  < 0.001). Dual-luciferase reporter assays revealed that miR-494 targeted SIRT1. Compared to control cells, HTR-8/SVneo cells with upregulation of miR-494 had remarkably downregulated SIRT1 expression ( p  < 0.001), more SAβG-positive cells ( p  < 0.001), cell cycle arrested ( p  < 0.05), and upregulated P21 and P16 expression ( p  < 0.01). miR-494 overexpression also decreased HTR-8/SVneo cell migration ( p  < 0.05) and ATP synthesis ( p  < 0.001), increased ROS levels ( p  < 0.001), and upregulated NLRP3 and IL-1β expression ( p  < 0.01). SIRT1-overexpressing plasmids partially reversed the effects of miR-494 overexpression in HTR-8/SVneo cells.

CONCLUSION: The miR-494/SIRT1 interaction plays a role in the mechanism of premature placental aging in PE patients.