Determining Sex-Specific Gene Expression Differences in Human Chorion Trophoblast Cells

Differences in male (M) and female (F) neonates' premature birth outcomes and placental trophoblast inflammation have been observed but are unknown to occur within the fetal membrane trophoblast layer (chorion trophoblasts [CTC]). This study examined whether sex-based differences in gene expression and inflammatory marker expression can be observed in CTCs under control or infectious inflammatory conditions modeling preterm birth. CTCs from six different patient-derived fetal membrane samples (3M/3F) were cultured and divided into experimental (Lipopolysaccharide [LPS]) and control groups for 6, 12, or 24 h. RNA from CTCs was subjected to RNA-seq, while cytokine multiplex or ELISA detected pro-/anti-inflammatory cytokines, progesterone, and soluble HLA-G in cell supernatants. CTC-M and CTC-F showed sex, time, and stimulant-dependent differential gene expression profiles. Cytokine analysis demonstrated a significantly lower IL-6 production in control CTC-M than in CTC-F. No sex-dependent responses were observed after LPS treatment regarding cytokines. CTC-M produced significantly lower progesterone than CTC-F. The theories of sexual dimorphism linked to placental inflammation may not extend to CTCs. This study supports that the chorion acts as a "great wall" protecting the fetus by being refractory to insults. Further examination into the weaknesses of the chorion barrier and sex-dependent responses of fetal membranes is needed.