Found programs: National Natural Science Foundation of China(No.82360261);Digital Development and Application of Biological Resources Project [2022] of Kunming Medical University(No.202002AA100007);High-level Talent Support Program of Yunnan Province(Young Top Talent Special Project)(No.KYQY20210816);The Open Project of the Clinical Medical Center for Reproductive Gynecological Diseases of Yunnan Province(No.2022LCZXKF-SZ14)
Authors：Zhang Yaqin; Ma Zhongrui; Qian Yuan; Li Junjun; Deng Xingli
Keywords：Down syndrome; miRNA; sequencing; amniotic fluid; placenta;
DOI：10.19405/j.cnki.issn1000-1492.2025.06.024
〔Abstract〕 Objective To analyze the differential expression profile of miRNAs in amniotic fluid exosomes of fetuses with Down syndrome(DS) and provide insights for identifying novel biomarkers for the prenatal diagnosis of DS. Methods Amniotic fluid samples were collected from fetuses with DS and chromosomally normal fetuses. Exosomes were isolated from the amniotic fluid and subjected to high-throughput sequencing. Differentially expressed miRNAs were identified, and target genes were predicted using TargetScan and miRanda. Target genes located on chromosome 21 were selected, and their biological functions and associated diseases were analyzed using GeneCards, HGNC, NCBI Gene, UniProtKB/Swiss-Prot, Ensembl, and OMIM databases. GO and KEGG enrichment analyses were performed to investigate the biological functions of the enriched genes. Results A total of 59 differentially expressed miRNAs were identified, including 31 upregulated and 28 downregulated miRNAs. Based on a fold change>2 andP<0.05, 10 upregulated and 9 downregulated miRNAs with the highest expression levels were selected. Key miRNAs included hsa-let-7b-5p, hsa-let-7c-5p, hsa-let-7b-3p＿1ss22CT, and hsa-miR-199b-5p, withBACH1andIFNAR1identified as their shared target genes. GO analysis revealed that the enriched target genes were primarily involved in protein binding, metal ion binding, transferase activity, DNA binding, transcriptional regulation by RNA polymerase Ⅱ, and nucleotide binding. KEGG pathway analysis indicated that the target genes were mainly associated with metabolic pathways, cancer-related pathways, the PI3K-Akt signaling pathway, and the Rap1 signaling pathway. Conclusion Differential expression of miRNAs in amniotic fluid exosomes was observed between DS fetuses and those with normal karyotypes. Combined analysis with placental miRNAs revealed hsa-miR-199b-5p as a common differentially expressed miRNA in both DS amniotic fluid and placenta. It is hypothesized thatBACH1andIFNAR1, shared target genes of hsa-miR-199b-5p, hsa-let-7b-5p, hsa-let-7c-5p, and hsa-let-7b-3p＿1ss22CT, may play a role in the pathogenesis of DS.