Upregulation of miR-145 may contribute to repeated implantation failure in vitro fertilization by targeting PAI-1

ABSTRACT Research question Repeated implantation failure (RIF) is a major limiting factor for assisted reproductive technology (ART). miR-145 is upregulated in patients with RIF. What is the underlying molecular mechanism of miR-145 on embryo implantation in RIF? Design Ishikawa cells were infected with lentivirus containing miR-145 and miR-145 NC, respectively. The massive transcriptome data analyses and bioinformatics analysis were used to seek a potential candidate target of miR-145. The expression of potential candidate target was detected using qPCR and western blot in Ishikawa cells infected with lentivirus containing miR-145 and miR-145 NC. Subsequently, the dual luciferase reporter assay was performed to verify whether the potential candidate target was a novel direct target of miR-145. In addition, we examined the expression of PAI-1 in RIF endometrial tissues and control endometrial tissues via qPCR and Immunohistochemistry. Results Based on massive transcriptome data analyses and bioinformatics analysis, PAI-1 was regarded as a potential candidate target of miR-145. miR-145 overexpression was achieved in Ishikawa cells. PAI-1 was confirmed as a direct target of miR-145 by bioinformatic analysis, qPCR, western blotting and dual luciferase reporter assay. Further, clinical sample results indicated that both at mRNA and protein levels, PAI-1 expression was obviously downregulated in RIF endometrial tissues when compared with control group, which was negatively correlated with miR-145 expression. Conclusions The study suggested that miR-145 may target and downregulate PAI-1 expression and influence embryo implantation in RIF patients undergoing IVF.