Placental methylation arrays for the assessment of epigenetic regulation in transcriptional subtypes of human preeclampsia

Preeclampsia (PE) is a complex, heterogeneous disorder of pregnancy, demonstrating considerable variability in observed maternal symptoms and fetal outcomes. We recently identified five clusters of placentas within a large gene expression microarray dataset (N=330, GSE75010), of which four contained a substantial number of PE samples. However, while transcriptional analysis of placentas can subtype patients, we hypothesized that the addition of epigenetic information should reveal gene regulatory mechanisms behind the distinct PE pathologies. We, therefore, subjected 48 of our samples to Infinium Human Methylation 450K arrays and investigated relationships between the gene expression and DNA methylation data. Bisulfite-converted DNA from 48 placentas belonging to transcriptional clusters 1, 2, 3, and 5 were hybridized to Illumina Infinium HumanMethylation450 BeadChips. Methylation data was analyzed separately, as well as integrated with matched gene expression information. Both the gene expression (from GSE75010) and methylation array data for these 48 placentas are available below.