Relevance of microRNAs to the regulation of the brain-placental axis in mice.

Introduction: The development of fetal brain is intricately dependent upon placental functions. Recently, we showed that the placenta and fetal brain express genes in a coordinated manner in mice. But, how the brain-placental axis is regulated at the molecular level remains poorly understood. The microRNAs (miRNAs) play diverse roles in pregnancy including regulation of placenta function as well as brain development. Thus, we hypothesized that specific miRNAs are expressed in the placenta and fetal brain to coordinate gene regulation in the brain-placental axis.

Methods: To test this hypothesis, we performed deep sequencing of small RNAs in mouse placenta and fetal brain of both sexes.

Results: The findings study show that miRNAs are potent regulators of gene expression in the placenta and fetal brain. Our data provides evidence that fetal sex influences the regulation of miRNAs between the placenta and fetal brain. Functional annotation of known target genes of the differentially expressed miRNAs show that they are significantly enriched with specific signaling and transporter pathways.

Discussion: Together, the results of this study suggest that placental miRNAs are potent regulators of fetal brain development in mice.