Project 3: The role of sex in ART-associated changes in trophoblast behavior and epigenetics

Project 3: Project Summary During pregnancy, sexual dimorphism can be seen throughout gestation. Sex-specific gene expression differences are present in the preimplantation embryo, and term placenta show differences in the transcriptome, the epigenome, histopathology and function. Sex-specific differences in adverse perinatal outcomes have also been observed - male fetuses are at increased risk for certain perinatal complications and more susceptible to some periconceptional and in utero exposures. Consistent with this data, we and others have found sex-specific differences in phenotype and outcome after exposure to specific assisted reproductive technologies (ART) interventions. Most recently, we demonstrated increased susceptibility of male human and mouse placentas to epigenetic perturbation following embryo vitrification. These findings have led us to hypothesize that sexually dimorphic trophoblast behavior and altered ART phenotypes occur due to the early effects of sex chromosome complement and sex steroids on the placental epigenome and transcriptome. However, our ability to study the cells and factors that control early pregnancy is limited by a lack of in vitro models available to study the early events of human placentation, which includes placental trophoblast differentiation, and trophoblast invasion. In this project, we propose using two innovative in vitro models capable of quantifying changes in trophoblast function and epigenetic and transcriptomic perturbations, to carry out a thorough examination of the sex-specific impact of ART interventions on early pregnancy. Specific Aim 1 will use an organ-on-chip device that recapitulates the maternal-fetal interface to examine how sex chromosome complement and sex hormones regulate trophoblast invasion. We will also examine how this regulation is affected by two ART-associated interventions, changes to the maternal hormonal environment and oxygen concentration. In Specific Aim 2, using induced pluripotent stem cell lines derived from control and ART placenta, we will examine how sex impacts trophoblast differentiation, and the effect of ART and ART- associated exposures on this process. These studies will leverage emerging, paradigm-shifting technologies to explore the impact of sex on early pregnancy, a time-point that has so far been inaccessible. Results from the proposed experiments will greatly advance our understanding of sexually dimorphic processes during placentation and further our knowledge of the pathways involved in sexually dimorphic responses to ART exposures, allowing us to modify protocols and develop interventional strategies to reduce adverse outcomes that lead to significant morbidity and mortality in both mother and child.