Regulation Of Epithelial-mesenchymal Transition By GRHL2 Gene Participate In The Mechanism Of Preeclampsia

BackgroundPreeclampsia(PE)is an idiopathic gestational disease,causing severe and adverse outcomes for the mother and fetus.Grainy-head like 2(GRHL2)has recently considered as one of the important transcriptional factors of epithelial-mesenchymal transition(EMT),playing a key role in the epithelial morphogenesis of maintaining,nervous system development,hearing loss and tumorigenesis.Studies have shown that the impaired EMT of trophoblasts could lead to the insufficient ability of migration and invasion of trophoblasts and inadequate remodeling of uterine spiral arterioles,thus resulting in the occurrence of PE.However,whether GRHL2 participates in the pathogenesis of PE by regulating the EMT process of trophoblasts is still unclear.ObjectiveTo detect the difference of GRHL2 expression in placental tissues between normal pregnant women and PE patients,and to explore the relationship between GRHL2 and the pathogenesis of PE.To study the EMT process and the effect of GRHL2 on the migration and invasion of the extravillous trophoblastic cell line in early pregnancy(HTR-8/SVneo cells),aiming to reveal the related mechanism of GRHL2 involved in the pathophysiology of PE.MethodsThe localization and different expression levels of GRHL2 in placenta of normal pregnant women and PE patients by immunohistochemistry,western blotting and real time-PCR were detected.HTR-8/SVneo cells were chosen as trophoblast cell models.The localization of GRHL2 protein in the HTR-8/SVneo cells through cellular immunofluorescence technique was examined.Cell transfection technique was used to change the expression levels of GRHL2 in HTR-8/SVneo cells,in addition,both western blotting and real time-PCR were applied to detect the expression levels of EMT-related molecular markers including E-cadherin,β-catenin,vimentin and N-cadherin.The effect of GRHL2 on the ability of migration and invasion in HTR-8/SVneo cells by transwell assay was assessed.ResultsGRHL2 was expressed in villous trophoblast cells and extravillous trophoblast cells of human placenta.The expression level of GRHL2 in placental tissues of PE patients was higher than that of normal pregnant women,and the differences were statistically significant.GRHL2 overexpression increased the expression level of epithelial molecular marker of β-catenin,decreased the expression level of mesenchymal molecular markers of vimentin and N-cadherin,and inhibited the migration and invasion of HTR-8/SVneo cells.GRHL2 knockdown decreased the expression level of β-catenin,increased the expression level of vimentin and N-cadherin,and promoted the migration and invasion of HTR-8/SVneo cells.ConclusionThis study demonstrated that the expression level of GRHL2 was elevated in placental tissue of PE patients.GRHL2 suppressed the migration and invasion by regulating the EMT process of trophoblast cells via up-regulating the expression of β-catenin,thus may cause impaired uterine spiral arterioles remodeling and promote the occurrence of PE.