miR-362-3p regulates cell proliferation, migration and invasion of trophoblastic cells under hypoxia through targeting Pax3.

Preeclampsia (PE), a common obstetrical disorder, is one of the leading causes of pregnancy associated death. PE is closely linked with impaired migration and invasion ability of trophoblastic cells. miR-362-3p recently received our particular attention due not only to its aberrant expression in the placentas of patients with PE, but also to its important roles in regulating migration and invasion of various cells. This study was thus conducted to investigate the roles of miR-362-3p in PE and the related mechanism. The expression of miR-362-3p and Pax3 was examined in placentas of patients with PE and in normal placentas. HTR8/SVneo cells were cultured under hypoxia and transfected with miR-362-3p mimics, miR-362-3p inhibitors or Pax3 over-expression vectors. Results showed up-regulation of miR-362-3p but down-regulation of Pax3 in placentas of preeclamptic pregnancies. Luciferase report assay confirmed that Pax3 is a direct target of miR-362-3p. Although Pax3 was predicted to be targeted by miR-30a-3p and miR-181a-5p as well, their expression either had no difference between placentas of PE patients and normal placentas or showed less increment in placentas of PE patients than miR-362-3p. Exposure to hypoxia inhibited cell viability, migration and invasion of HTR8/SVneo cells. Increasing miR-362-3p by the mimics conferred improved effects on the inhibition. However, deletion of miR-362-3p or overexpression of Pax3 abolished the inhibiton. These results suggest that miR-362-3p/Pax3 axis regulates cell viability, migration and invasion of HTR8/SVneo cells under hypoxia. The present study adds to the further understanding of the pathogenesis of PE.