Deregulated microRNA species in the plasma and placenta of patients with preeclampsia.

Emerging evidence indicates that microRNAs (miRNAs), a class of small non-coding RNAs, are involved in a number of biological processes. The results of SOLiD™ sequencing were used to analyze differentially expressed miRNA profiles in the plasma and placenta of patients with preeclampsia (PE) and a subject who had had a pregnancy without complications. miRNAs were identified that were consistently expressed in the placenta, following normalization of the raw data. miRNAs that had increased and differential expression were selected, as defined by percentage >0.02% and a log2 fold change ≥ |1.2|, respectively. This process was repeated in the plasma. Twenty such miRNAs were identified. These were: miR-126, miR-126*, miR-130a, miR-135b, miR-142-3p, miR-149, miR-188-5p, miR-18a, miR-18b, miR-203, miR-205, miR-224, miR-27a, miR-29a, miR-301a, miR-517c, miR-518-3p, miR-518e, miR-519d and miR-93. These miRNAs belonged to 13 clusters or families. However, only four clusters or families involved two or more of these miRNAs. These were the mir-16 cluster, the mir-17 family, the mir-130 family and the mir-517 family. These abnormally-expressed miRNAs and miRNA gene clusters or families are known to be involved in a number of biological processes. Gene enrichment analysis was used to investigate the pathways involved in the development of PE. In conclusion, the miRNAs identified in this study as being abnormally expressed in PE, may be useful as non-invasive diagnostic biomarkers. Co-regulated mRNAs and possible causal pathways involved in the pathogenesis of PE were also identified.