Human Trophoblast Differentiation Is Associated With Profound Gene Regulatory and Epigenetic Changes

Abstract

Defective placental implantation and vascularization with accompanying hypoxia contribute to preeclampsia (PE), a leading cause of maternal and neonatal morbidity and mortality. Genetic and epigenetic mechanisms underlying differentiation of proliferative cytotrophoblasts (CytTs) to multinucleated syncytiotrophoblast (SynT) are incompletely defined. The SynT performs key functions in nutrient and gas exchange, hormone production, and protection of the fetus from rejection by the maternal immune system. In this study, we used chromatin immunoprecipitation sequencing of midgestation human trophoblasts before CytT and after SynT differentiation in primary culture to analyze changes in binding of RNA polymerase II (Pol II) and of active and repressive histone marks during SynT differentiation. Our findings reveal that increased Pol II binding to promoters of a subset of genes during trophoblast differentiation was closely correlated with active histone marks. This gene set was enriched in those controlling immune response and immune modulation, including interferon-induced tetratricopeptide repeat and placenta-specific glycoprotein gene family members. By contrast, genes downregulated during SynT differentiation included proinflammatory transcription factors ERG1, cFOS, and cJUN, as well as members of the NR4A orphan nuclear receptor subfamily, NUR77, NURR1, and NOR1. Downregulation of proinflammatory transcription factors upon SynT differentiation was associated with decreased promoter enrichment of endogenous H3K27Ac and H3K9Ac and enhanced binding of H3K9me3 and histone deacetylase 1. However, promoter enrichment of H3K27me3 was low in both CytT and SynT and was not altered with changes in gene expression. These findings provide important insight into mechanisms underlying human trophoblast differentiation and may identify therapeutic targets for placental disorders, such as PE.

Regulation of human trophoblast syncytialization by histone demethylase LSD1

“…6). Our findings also support a recent study, which showed that CTB to SynTB differentiation is associated with increased RNA-POL-II binding to promoters of a subset of genes (83). However, we found that GATA2 is also expressed in the undifferentiated BeWo cells.…”

Data-Driven Modeling of Pregnancy-Related Complications

“…While genetic contributions to different complications in pregnancy are probably polygenic, genome-wide association studies (GWASs) have found genetic variants associated specifically with sPTB, illustrating how a mother's genetic makeup can set the stage for fetal development and pregnancy outcome even before conception [71][72][73]. By contrast, maternal epigenetic modifications reflect the state of different cell types across tissues as they reprogram to prepare for fetal growth [74,75]. Quantification of these modificationsby measuring DNA methylation, histone markers, and chromatin accessibility in the cell subsets of interestoffers insights into whether different cell types in the maternal-fetal interface are adapting properly for a successful pregnancy [76,77].…”

Histone deacetylase 1 and 2 drive differentiation and fusion of progenitor cells in human placental trophoblasts

“…Recent derivation of human trophoblast stem cells was made possible, in part, by using an HDAC inhibitor to maintain cells in a stem state, suggesting a critical role for HDAC activity in human trophoblast differentiation 25 . Indeed, differentiation of primary human cytotrophoblasts is associated with profound changes in histone acetylation, including gene-and promoter-specific changes in H3K9 and H3K27 acetylation 26 . Collectively, these studies emphasize the critical role of histone acetylation dynamics and HDAC activity in the regulation of trophoblast differentiation and placental development, which prompted us to investigate the functional role of specific HDACs during human syncytiotrophoblast formation.…”