Post-Transcriptional Regulation by microRNAS in Pregnancy and Parturition
Renthal, Nora Edwards
MetadataShow full item record
Throughout most of pregnancy, uterine quiescence is maintained by increased progesterone receptor (PR) transcriptional activity, while spontaneous labor is initiated/facilitated by a concerted series of biochemical events that activate inflammatory pathways and negatively impact PR function. In this study, we uncovered a new regulatory pathway whereby miRNAs serve as hormonally-modulated and conserved mediators of contractile gene regulation in the pregnant uterus from mouse to human. Using miRNA and gene expression microarray analyses of uterine tissues, we identified a conserved family of miRNAs, the miR-200 family, that is highly induced at term in both mice and humans, as well as two coordinately downregulated targets, zinc finger E-box binding homeobox proteins, ZEB1 and ZEB2, which act as transcriptional repressors. We also observed upregulation of the miR-200 family and downregulation of ZEB1 and ZEB2 in two different mouse models of preterm labor. We further demonstrated that ZEB1 is directly upregulated by the action of P4/PR at the ZEB1 promoter. Excitingly, we observed that ZEB1 and ZEB2 inhibited expression of the contraction-associated genes, oxytocin receptor and connexin-43 and blocked oxytocin-induced contractility in human myometrial cells. Together, these findings implicate the miR-200 family and their targets ZEB1 and ZEB2 as novel P4/PR-mediated regulators of uterine quiescence and contractility during pregnancy and labor, and shed new light on the molecular mechanisms involved in preterm birth.