Underexpression of 4 placenta-associated microRNAs in complete hydatidiform moles

Several placental microRNAs (miRNAs) have been identified as placenta-associated miRNAs with the potential of estimating the condition of the placenta. However, our understanding of these miRNAs is limited. The aim of this study was to determine the expression of 8 placenta-associated miRNAs (miR-512-3p, miR-517a, miR-517b, miR-518b, miR-519a, miR-1185, miR-1283, and miR-1323) in complete hydatidiform mole (CHM).

Samples were obtained from patients with CHM (CHM group, n = 12) and elective terminations of normal pregnancy (control group, n = 20). We detected differentially expressed placenta-associated miRNAs in placenta by quantitative real-time reverse transcriptase-polymerase chain reaction analysis. Subsequently, we assessed the expression location of differentially expressed miRNAs by in situ hybridization analysis.

Four placenta-associated miRNAs (miR-517a, miR-517b, miR-518b, and miR-519a) were underexpressed in the CHM group, compared with the control group (P < 0.01). When further investigating these 4 miRNAs with regard to in vivo localization by in situ hybridization, we found that 2 miRNAs (miR-517b and miR-518b) were detected exclusively in the trophoblast layer, with little signal (if any) observed in villous stroma cells.

The results show that 4 miRNAs (miR-517a, miR-517b, miR-518b, and miR-519a) are deregulated in CHM, which suggests the involvement of these miRNAs in the functions of CHM placenta.