SRI 2020: Scientific Abstracts

Abstract

Introduction: Previous studies have suggested that altered expression of some microRNAs (miRNAs) have a role in pregnancy complications like preeclampsia and spontaneous preterm delivery (SPTD). Placenta has proposed regulatory roles in initiation of labor. It is known that there are three separate placenta specific miRNA clusters: miR-371-3 cluster, C14MC and C19MC. This study focuses on the changes of placenta microRNA profiles between placentas from SPTD, spontaneous term (STD) and elective term (ETD) births. As miRNAs have multiple gene targets, altered miRNA expression may cause changes in many biological pathways that influence the length of pregnancy and onset of birth. The aim was to discover changes in miRNA expression that may play a role in determining length of pregnancy and onset of preterm birth. Methods: We performed microRNA omics study where we compared microRNA transcriptome of placentas from SPTD and STD after vaginal delivery and from ETD. miRNAs from basal plates of altogether 18 placentas were purified and microRNA transcriptomes were determined. Transcriptional profiles of SPTD (n = 6), STD (n = 6) and ETD (n = 6) placental microRNAs were detected by sequencing. Some of the observed changes were verified by RT-qPCR. Results: Sequencing data analysis showed that there are 13 miRNAs upregulated and 28 downregulated in SPTD placentas compared to STD placentas (fold change FC >1.5, p < 0.05). 33 miRNAs are upregulated, 42 miRNAs are downregulated in STD compared to ETD placentas, and 17 miRNAs are upregulated and 30 miRNAs downregulated in SPTB compared to ETD placentas respectively. Almost all members of placenta specific miR-371-3 cluster were upregulated in both SPTD and STD placentas compared to ETD placentas. Pathway analysis demonstrated that miRNAs with altered expression target genes having role in cancer and infection related pathways. Conclusion: Our results show that miRNA transcriptome of placenta from SPTD, STD and ETD differ between the three groups. As members of placenta specific miR-371-3 cluster were upregulated in both SPTD and STD placentas compared to ETD placentas it may indicate that expression of this cluster plays a role in the onset of labor.