Preeclampsia leads to dysregulation of various signaling pathways in placenta.

Objectives: To compare gene expression profiles of placentas from preeclamptic and normal pregnancies.

Study Design: We performed microarray experiments to analyze genome-wide expression profiling for 10 placentas from pregnant women with preeclampsia and 10 placentas from women who experienced noncomplicated pregnancies (CON), and to identify dysregulated signaling pathways as well as genes in preeclampsia. RT-PCR, real-time RT-PCR and/or immunofluorescence analyses were performed to validate the data obtained from microarray experiments.

Results: Unsupervised hierarchical clustering showed heterogeneity of preeclampsia at the molecular levels, whereas expression profiles of preeclampsia are distinctly different from those of CON. A list of genes which are differentially expressed between preeclampsia and CON included well known preeclampsia markers, such as Flt-1, leptin, HTRA1 and SIGLEC6. Gene Set Enrichment Analysis, a pathway-oriented analysis method for expression profiles, provided evidence that a number of biological activities including pathways that regulate actin cytoskeleton, TGFβ signaling, oxidative phosphorylation, and proteasome activity were aberrantly either up-regulated or down-regulated in preeclampsia. RT-PCR and real-time-RT-PCR for genes contributing these biological pathways (gene sets) enriched in either CON or preeclampsia reinforced that these biological processes were systemically dysregulated in preeclampsia.

Conclusions: Genome-wide expression profiles of preeclampsia showed heterogeneous characteristics of preeclampsia at the molecular levels. Dysregulation of genes and biological pathways could contribute to abnormal behavior of preeclmapsia. Our results will help further understand underlying mechanisms by which preeclampsia affects placental physiology.