Background
The primary interface between mother and fetus, the placenta, serves two critical functions: extraction of nutrients from the maternal compartment and facilitation of nutrient delivery to the developing fetus. This delivery system also serves as a barrier to environmental exposures. The aryl hydrocarbon receptor (AHR) is an important component of the barrier. AHR signaling is activated by environmental pollutants and toxicants that can potentially affect cellular and molecular processes, including those controlling trophoblast cell development and function. Objectives: In this study, we investigated the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an effective AHR ligand, exposure on human trophoblast cells.
Discussion
Human trophoblast cell responses to TCDD were dependent upon AHR signaling and possessed the potential to shape development and function of the human placentation site.
Methods
Human trophoblast stem (TS) cells were used as in vitro model system for investigating the downstream consequences of AHR activation. The actions TCDD were investigated in human TS cells maintained in the stem state or in differentiating TS cells.
Results
TCDD exposure stimulated the expression of CYP1A1 and CYP1B1 in human TS cells. TCDD was effective in stimulating CYP1A1 and CYP1B1 expression and altering gene expression profiles in human TS cells maintained in the stem cell state or induced to differentiate into extravillous trophoblast cells (EVT) or syncytiotrophoblast (ST). These actions were dependent upon the presence of AHR. TCDD exposure did not adversely affect maintenance of the TS cell stem state or the ability of TS cells to differentiate into EVT cells or ST. However, TCDD exposure did promote the biosynthesis of 2 methoxy estradiol (2ME), a biologically active catechol estrogen, with the potential to modify the maternal-fetal interface.