Effects of sirtuin 1 deficiency on trophoblasts and its implications in the pathogenesis of pre-eclampsia

Sirtuin 1 (SIRT1) is mainly localised in syncytiotrophoblasts and cytotrophoblasts, and is involved in pregnancy regulation. However, data on the association between SIRT1 and pre-eclampsia (PE) remains limited. This study aimed to investigate the role of SIRT1 in PE pathophysiology. Placental SIRT1 expression, as well as serum SIRT1, placental growth factor (PlGF), and soluble FMS-like tyrosine kinase 1 (sFlt-1) levels, were measured using quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assays in 40 healthy pregnant women (NP group) and 40 women with severe PE (PE group). Additionally, the effects of SIRT1 on the migration, invasion, PlGF, and sFlt-1 secretion of HTR-8/SVneo cells were analysed. SIRT1 expression was significantly reduced in the placenta of patients with severe PE compared with that in healthy pregnant women. Compared with the NP group, serum SIRT1 and PlGF expression was significantly lower in the PE group; however, the expression of serum sFlt-1 was significantly higher in the PE group. Correlation analysis showed that in the PE group, placental SIRT1 protein levels positively correlated with serum PlGF levels (<i>r</i> = 0.468, <i>P</i> = .002) and negatively correlated with serum sFlt-1 levels (<i>r</i> = −0.542, <i>P</i> &lt; .001). Cells with downregulated SIRT1 had a significantly shorter migration distance and a prominently reduced number of invasive cells compared with the corresponding negative control group, suggesting that SIRT1 deficiency may inhibit the migration and invasive ability of HTR-8/SVneo cells. The opposite results were observed after transfection with lentivirus overexpressing SIRT1. Compared with the corresponding controls, cells with downregulated SIRT1 had significantly reduced PlGF levels and significantly increased sFlt-1 levels in the cell culture supernatants, whereas SIRT1 overexpression produced the opposite results. SIRT1 deficiency may contribute to the pathogenesis of pre-eclampsia by reducing trophoblastic migration, invasion, and PlGF secretion and increasing sFlt-1 secretion. Pre-eclampsia is a serious obstetric disorder that begins in the placenta and can occur midway through pregnancy. However, its exact disease process remains unknown. During early pregnancy, trophoblasts (cells that differentiate from fertilised eggs) evolve into new blood vessels that supply oxygen and nutrients to the placenta and maintain placental formation. In people with pre-eclampsia, problematic trophoblasts lead to abnormal placental formation and release of sFlt-1 and PlGF into the mother’s blood, damaging blood vessels. Experts reported that the intracellular enzyme SIRT1 might be associated with developing pre-eclampsia. SIRT1 expression in the placenta of pregnant women with pre-eclampsia was lower than normal, and the decrease in SIRT1 levels in HTR-8/Svneo trophoblasts prevented their ability to form blood vessels and altered sFlt-1 and PlGF secretion. Hence, our findings suggest that reduced SIRT1 in trophoblasts may lead to pre-eclampsia by affecting their ability to form placental blood vessels and altering enzyme secretion.