Expression and role of miR-146a and SMAD4 in placental tissue of pregnant women with preeclampsia.

Introduction: To investigate the expression of miR-146a in severe preeclampsia (PE) and its effect on trophoblast cell proliferation, invasion and apoptosis, as well as its relationship with SMAD4.

Material And Methods: Participants were divided into the severe PE group (n = 30) and the normal group (n = 30). The expression of miR-146a and SMAD4 in placenta tissue was detected by immunohistochemistry, qRT-PCR, and western blot. Trophoblast cell lines HTR-8/SVneo were cultured to detect the expression of miR-146a under the Cobalt chloride (CoCl )-simulated hypoxia. The effects of miR-146a transfection on cell proliferation, invasion, apoptosis, and SMAD4 expression were analyzed.

Results: Compared with the normal group, miR-146a expression was decreased and the protein and mRNA levels of SMAD4 were increased in placenta tissues of the severe PE group. Our in vitro experiments showed that the expression of miR-146a decreased after CoCl treatment. Silencing miR-146a caused increased expression of SMAD4 and decreased expression of VEGF. After transfection with miR-146a inhibitor, compared with the NC group, the invasion and proliferation of HTR-8/Svneo cells were decreased, while the apoptosis was enhanced.

Conclusion: The expression of miR-146a decreased in severe PE and was negatively correlated with SMAD4 expression. The expression of miR-146a was inhibited under hypoxia, and the low expression of miR-146a affected the proliferation, invasion, and apoptosis of trophoblast cells.