Oxidative Stress Alters miRNA and Gene Expression Profiles in Villous First Trimester Trophoblasts

The relationship between oxidative stress and miRNA changes in placenta as a potential mechanism involved in preeclampsia (PE) is not fully elucidated. We investigated the impact of oxidative stress on miRNAs and mRNA expression profiles of genes associated with PE in villous 3A first trimester trophoblast cells exposed to H₂O₂ at 12 different concentrations (0-1 mM) for 0.5, 4, 24, and 48 h. Cytotoxicity, determined using the SRB assay, was used to calculate the IC₅₀ of H₂O₂. RNA was extracted after 4 h exposure to H₂O₂ for miRNA and gene expression profiling. H₂O₂ exerted a concentration-and time-dependent cytotoxicity on 3A trophoblast cells. Short-term exposure of 3A cells to low concentration of H₂O₂ (5% of IC₅₀) significantly altered miRNA profile as evidenced by significant changes in 195 out of 595 evaluable miRNAs. Tool for annotations of microRNAs (TAM) analysis indicated that these altered miRNAs fall into 43 clusters and 34 families, with 41 functions identified. Exposure to H₂O₂ altered mRNA expression of 22 out of 84 key genes involved in dysregulation of placental development. In conclusion, short-term exposure of villous first trimester trophoblasts to low concentrations of H₂O₂ significantly alters miRNA profile and expression of genes implicated in placental development.