Mature miR-99a Upregulation in the Amniotic Fluid Samples from Female Fetus Down Syndrome Pregnancies: A Pilot Study

Abstract

Background and Objective: Although Down syndrome is the most frequent aneuploidy, its pathogenic molecular mechanisms are not yet fully understood. The aim of our study is to quantify—by qRT-PCR—the expression levels of both the mature forms and the pri-miRNAs of the microRNAs resident on chromosome 21 (miR(21)) in the amniotic fluid samples from Down syndrome singleton pregnancies and to estimate the impact of the differentially expressed microRNAs on Down syndrome fetal heart and amniocytes transcriptomes. Materials and methods: We collected amniotic fluid samples harvested by trained obstetricians as part of the second trimester screening/diagnostic procedure for aneuploidies to assess the trisomy 21 status by QF-PCR and karyotyping. Next, we evaluated—by Taqman qRT-PCR—the expression levels of both the mature forms and the pri-miRNA precursors of the microRNAs resident on chromosome 21 in amniotic fluid samples from singleton Down syndrome and euploid pregnancies. Further, we combined miRWalk 3.0 microRNA target prediction with GEO DataSets analysis to estimate the impact of hsa-miR-99a abnormal expression on Down syndrome heart and amniocytes transcriptome. Results: We found a statistically significant up-regulation of the mature form of miR-99a, but not pri-miR-99a, in the amniotic fluid samples from Down syndrome pregnancies with female fetuses. GATHER functional enrichment analysis of miRWalk3.0-predicted targets from Down syndrome amniocytes and fetal hearts transcriptome GEODataSets outlined both focal adhesion and cytokine–cytokine receptor interaction signaling as novel signaling pathways impacted by miR-99a and associated with cardiac defects in female Down syndrome patients. Conclusions: The significant overexpression of miR-99a, but not pri-miR-99a, points towards an alteration of the post-transcriptional mechanisms of hsa-miR-99a maturation and/or stability in the female trisomic milieu, with a potential impact on signaling pathways important for proper development of the heart.

Differential lncRNA/mRNA expression profiling and ceRNA network analyses in amniotic fluid from foetuses with ventricular septal defects

“…Recently, studies have shown that AF provides dynamic ncRNA information about foetal pathophysiological status inside the uterus. Vizitiu et al (2019) showed that miR-99a was significantly upregulated in the AF of foetuses with trisomy 21 syndrome. Xie et al (2017) found that AF-derived miR-299-5p and miR-300 could be used as biomarkers to evaluate foetal kidney function and prenatally diagnose congenital hydronephrosis.…”

MicroRNAs miR-4535 and miR-1915-5p in Amniotic Fluid As Predictive Biomarkers for Chorioamnionitis

“…Recently, the miRNA profiling of amniotic fluid was reported, suggesting that miRNAs in the amniotic fluid may contribute to fetal development [42]. The relationship between miRNAs in the amniotic fluid and fetal congenital diseases including chromosomal anomalies has also been investigated [43][44][45]. In chorioamnionitis miR-548, which is highly expressed in the amniotic membrane, alters the inflammatory responses through the regulated expression of HMGB1, and miR-223 and miR-338 are also abundantly expressed in the chorioamniotic membranes [46,47].…”