Overexpression of miR-21 and miR-122 in preeclamptic placentas.

OBJECTIVE: Preeclampsia is a pregnancy-associated disease with the impact of genetic, epigenetic and environmental factors. Increased apoptosis was observed in cells from preeclamptic placentas. MicroRNAs are involved in the regulation of apoptosis and are abundant in placenta. In this study, we focused on the analysis of differential gene expression of apoptosis-associated miRNAs in preeclamptic placenta samples compared to the samples obtained from healthy pregnant women.

METHODS: MicroRNA was extracted from placental samples of patients with preeclampsia and physiological course of the pregnancy. The gene expression of miR-155, miR-122 and miR-21 in placenta and control samples was estimated by relative quantitation (RQ) using TaqMan probes, normalized against RNU44. The RQ mean values were statistically evaluated by Man-Whitney test.

RESULTS: Using the relative gene expression analysis, we could observe a significant increase in gene expression of miR-155 (p<0.001), miR-21 (p<0.0001) and miR-122 (p<0.01) in preeclamptic placentas.

CONCLUSION: The apoptosis-associated miRNAs miR-21 and miR-122 are dysregulated in the term preeclamptic placentas. The increased miRNA expression suggest the downregulation of potential targets mRNAs, which can contribute to the pathogenesis of preeclampsia. The identification of their targets in placenta will improve our understanding of their role in preeclampsia.