Mir-218-5p from Extracellular Vesicles of Endometrium in Patients with Recurrent Implantation Failure Impairs Pre-Implantation Embryo Development

BACKGROUND: Recurrent implantation failure (RIF) presents a crucial obstacle to in vitro fertilization success. Previous research has shown that small extracellular vesicles (EVs) from endometrial RIF patients hinder embryo development, yet the underlying mechanism and potential solutions remain largely unexplored. In this study, we aimed to investigate the effectiveness of miR-218-5p as a molecular factor in RIF-EVs. Our findings revealed that miR-218-5p disrupted mouse embryo development, and this effect could be reversed by engineered extracellular vesicles (E-EVs) containing anti-miR-218-5p. METHODS: The percentage of blastocyst development and hatching rates, embryo morphology, and the total cell number were measured. RNA-sequencing was used to analyze transcriptional changes in embryos post miR-218-5p agomir treatment. The abnormal segregation genes of trophectoderm (TE) and inner cell mass (ICM) were visualized via qRT-PCR and immunofluorescence staining. The E-EVs were using the EVs derived from Human Umbilical Cord Mesenchymal Stem Cells (HUMSCs). Characteristics of the EVs were measured using Western blotting, nanoparticle tracking analysis, and transmission electron microscopy. EVs internalization was visualized using BODIPY TR ceramide staining. RESULTS: Mouse embryos were arrested at the morula stage and demonstrated reduced blastocyst and hatching rates following miR-218-5p agomir treatment (P < 0.001). Essential transcription factors for TE and ICM, such as Cdx2, Yap1, Sox2, Nanog, Tead4, were reduced at the mRNA level in the miR-218-5p treated morula. This was accompanied by decreased Cdx2 protein levels at the 8-16-cell stage (P < 0.001) and disruption of co-localization of Yap1 and Cdx2. The blastocyte rate was increased by anti-miR-218-5p-encapsulated E-EVs compared with miR-218-5p group (P < 0.001). CONCLUSION: This study offers valuable insights into the potential role of miR-218-5p in RIF and presents. The utilization of engineered vesicles containing anti-miR-218-5p may present a promising avenue for patients facing challenges with RIF.