Maternal microRNAs Linked To Birth Deficits Due To Prenatal Alcohol Exposure Are Dominant Modifiers of Gene Expression in Invasive Trophoblast Cells

Prenatal alcohol exposure (PAE) can impair placental development and result in fetal growth restriction. However, the underlying molecular mechanisms are unclear. We previously found that PAE in some, but not all pregnancies, resulted in significantly elevated circulating levels of 11 microRNAs (HEamiRNAs) in the 2nd trimester. This subgroup of PAE women experienced adverse infant birth outcomes due to PAE, Subsequently, these HEamiRNAs collectively but not individually, were found to inhibit a defined set of placental epithelial-mesenchymal transition (EMT) genes and, inhibited invasiveness of placental trophoblast cells. Here we extend these findings by performing whole-transcriptome analysis to dissect the contribution of ethanol compared to HEamiRNAs in HTR-8/SVneo cells, a model for invasive, human extravillous trophoblasts. We observed a large, distinct and statistically dominant effect of HEamiRNAs mimics on trophoblast transcript profiles irrespective of ethanol exposure, specifically on EMT, extracellular matrix, angiogenesis and immune signaling pathways among others. Weighted gene co-expression network analysis (WGCNA) identified additional placental growth networks related to epithelial cell proliferation and differentiation and MAPK/PI3K, Hippo and Rap1 signaling. This study provides a mechanistic framework to explain that the effects of PAE vary across pregnancies, because they are contingent in part, on the elevation key maternal circulating miRNAs.