Dysregulation of Chromosome 14 MicroRNA Cluster and Chromosome 19 MicroRNA Cluster MicroRNAs in Chorionic Villous Tissue of Cases With Recurrent Spontaneous Abortion.

Recurrent spontaneous abortions (RSA) are defined as a loss of two or more consecutive clinically recognized pregnancies before the 20th week of gestation. In RSA, several causative factors are known, but still, 50% of the cases remain unexplained. Two large clusters of microRNAs (miRNAs), namely C14MC (Chromosome 14 microRNA cluster) and C19MC (Chromosome 19 microRNA cluster), are imprinted and expressed in the placenta. Hence, we studied the expression of miRNAs coded by these clusters and their mRNA targets in RSA cases in order to elucidate the involvement of these two clusters in the pathogenesis of RSA. Upon miRNA sequencing, we found a total of seven miRNAs to be differentially expressed in RSA group. Further, using bioinformatics tools such as TargetScan and DAVID pathway analysis, we found that the mRNA targets were involved in the functionally relevant processes of the placenta such as cell migration, cell-cell adhesion, and angiogenesis. Upon validation of sequencing data, we found differential expression of five miRNAs from C14MC and C19MC clusters and differential expression of genes regulating processes such as cell migration, cell adhesion, and angiogenesis in RSA cases which are targeted by these miRNAs.