KLF12 Transcriptional Inhibition Of FOXO1 Expression Leads To Endometrial Decidualization Disorders

KLF12,a member of Krüppel-like transcriptional factor family,repressed decidual marker genes PRL and IGFBP1 expression.When KLF12 overexpression,human endometrial stromal cells(HESCs)displayed a poorly formed,diffuse network of actin cytoskeleton.KLF12 negatively regulated HESCs decidualization,however,little is known about the effector mechanism involved.Based on the previous description,this study aimed to explore the mechanism of KLF12 during the decidualization of endometrial stromal cells and provide a new line of evidence correlating the repeated implantation failure(RIF).Using natural pregnant mouse,we reported that KLF12 inhibited the mouse embryo implantation process.The rate of embryo implantation decreased 38.6% which was observed in the uteri with KLF12 overexpression(n=11,p=0.0051).We further demonstrated that KLF12 interfered with the pseudopregnant implantation sites and uterine weight ratio of the stimulus to control,as well as placental formation via artifical decidualization mouse model.Using real-time PCR,we showed that the expression of mouse decidual marker gene dPRP was significantly decreased(about200 times);FOXO1 mRNA level decreased as well.Using isolated uterine stromal cells,we showed adenovirus-mediated overexpression of KLF12 in HESCs markedly attenuated the level of FOXO1 mRNA and protein.Moreover,the decidualized stimulus of 8-Br-cAMP plus MPA enlarged the downregulation.By chromatin immunoprecipitation(ChIP)PCR,Avdin-biotin conjugate DNA precipitation and luciferase reporter gene assay,we observed KLF12 bound to the CAGTGGG sequence in the promotor of FOXO1,which was located in the-2624/-2617 bp from the transcription start site,and transcriptionally repressed FOXO1.Clinical endometrial sample studies showed that KLF12 were abnormally overexpressed in the endometrium of women with repeated implantation failure(RIF).By contrast,mRNA and protein level of FOXO1 were less than that of control group.Concomitantly,the protein level of FOXO1 was moderately negatively correlated with that of KLF12 in patients with RIF(r=-0.4272395,p=0.04202).In conclusion,all the results above indicated that,by transcriptional regulation FOXO1 expression,KLF12 repressed the decidualization process in vivo and vitro.We further explained the potential molecular mechanism of RIF from the point of impaired decidualization,which would served as a diagnose and treatment evidence for the unexplained RIF.