As susceptibility to many adult disorders originates in utero, we here hypothesized that fetal sex influences gene expression in placental cells and produces functional differences in human placentas. We found that fetal sex differentially affects gene expression in a cell-phenotype dependent manner among all four placental cell-phenotypes studied: cytotrophoblasts, syncytiotrophoblasts, arterial endothelial cells and venous endothelial cells. The markedly enriched pathways in males were identified to be signaling pathways for graft-versus-host disease as well as the immune and inflammatory systems, both supporting the hypothesis that there is reduced maternal-fetal compatibility for male fetuses. Our study is the first microarray study investigating sexual dimorphism in purified and characterized somatic cells from a single human tissue, the placenta, that underlines the importance of considering fetal sex as an independent variable in any work using human placenta.
Overall design
Arterial and venous endothelial cells were isolated from eight different placentas, four of each sex. A total of ten placentas were used for isolation of cytotrophoblasts and six for syncytiotrophoblasts, with equal numbers from each sex.