iPSC-based modeling of preeclampsia identifies defects in extravillous trophoblast differentiation

Preeclampsia (PE) is a hypertensive pregnancy disorder with increased risk of maternal and fetal morbidity and mortality. Abnormal extravillous trophoblast (EVT) development and function is considered to be the underlying cause of PE, but has not previously been modeled in vitro. We previously derived induced pluripotent stem cells (iPSC) from placentas of PE patients and characterized abnormalities in formation of syncytiotrophoblast and responses to changes in oxygen tension. In this study, we converted these primed iPSC to naive iPSC, then derived trophoblast stem cells (TSC) and EVT to evaluate molecular mechanisms underlying PE. We found that primed (but not naive) iPSC-derived PE-EVT have reduced surface HLA-G, blunted invasive capacity, and altered EVT-specific gene expression. These abnormalities correlated with promotor hypermethylation of genes associated with the epithelial-mesenchymal transition pathway, specifically in primed-iPSC derived PE-EVT. Our findings indicate that abnormal epigenetic regulation might play a role in the PE pathogenesis.