microRNA-614 contributes to recurrent miscarriage through targeting FOXD1

OBJECTIVE: Recurrent miscarriage (RM) is a significant reproductive health issue affecting many women of childbearing age. The objective of this study was to evaluate the value of microRNA-614 (miR-614) as a potential biomarker for RM and to elucidate its functional mechanism. METHODS: Differentially expressed miRNAs (DEmiRs) were first screened from the Gene Expression Omnibus (GEO) database using a bioinformatics approach. A total of 135 patients with RM and 135 healthy controls were included. The expression levels and diagnostic performance of miR-614 were evaluated by RT-qPCR and ROC curve analysis. CCK-8 and Transwell were performed to assess the impact of the miRNA on trophoblast cell proliferation, invasion, and migration. For target gene verification, TargetScan 8.0 was utilised for prediction, followed by a luciferase activity assay to confirm direct regulation by miRNA. RESULTS: Bioinformatic interrogation of the GSE73025 dataset revealed a significant down-regulation of miR-614. Plasma miR-614 was significantly downregulated in RM patients. The area under the ROC curve (AUC) for miR-614 in distinguishing RM patients from controls was 0.865 (95% CI: 0.823-0.907, sensitivity = 77.78%, specificity = 77.78%). The AUC for predicting adverse pregnancy outcomes was 0.790 (95% CI: 0.708-0.870, sensitivity = 71.08%, specificity = 82.69%). Transfection with miR-614 mimics decreased the proliferation, invasion, and migration of HTR-8 and JEG3 cells. miR-614 Directly targets FOXD1 and negatively modulates its mRNA expression to drive RM progression. CONCLUSION: In RM patients, miR-614 is downregulated, leading to increased FOXD1 expression. miR-614 mimics suppresses trophoblast proliferation, migration, and invasion by directly targeting FOXD1. Thus, miR-614 downregulation contributes to RM pathogenesis by directly targeting FOXD1, thereby upregulating FOXD1 and inhibiting the proliferation, invasion, and migration of trophoblast cells.