Alterations in maternal plasma exosomal miRNAs revealed selective material exchange between maternal circulation and placenta

Aim Exosomes have emerged as important regulators in the communication between maternal peripheral blood and placenta. We aimed to compare maternal plasma exosomal miRNAs profile between healthy pregnant and nonpregnant women, screen for differential expressed miRNAs and their potential regulatory role during pregnancy. Methods We isolated exosomes from plasma of mid-trimester, last trimester, and nonpregnant women (n = 6 each group), analyzed the miRNA profile using next-generation sequencing. Results Several miRNA clusters were expressed in plasma exosomes, such as C19MC, C14MC, and let-7 family, miRNAs in each cluster may have synergistic effect during pregnancy. We assumed maternal circulating exosomal miRNA could be transported into placenta or selectively uptook by placenta, which was consistent with the fact that many pregnancy-associated or placenta highly expressed miRNAs reduced in exosomes during pregnancy. Some exosomal miRNAs were mainly secreted by the placenta, which could act as markers that reflect changes in the function and microenvironment of the placenta. Conclusions Exosomal miRNAs are associated with placenta development and have potential as molecular markers.