miRNA Targets Function of miRNA Model Reference Normal pregnancy status
miR-148 HLA-G Down-regulates HLA-G expression JEG-3 cells
Human placenta (extravillous trophoblast)
[32,35] Down-regulated
miR-148a HLA-C Down-regulates HLA-C expression Cell line [34] Down-regulated
miR-152 HLA-G Down-regulates HLA-G expression Human placenta (extravillous trophoblast) [35] Down-regulated
miR-181 Suppression of nemo-like kinase Development of NK cells Human CD34+cells
Human placenta
[37] Down-regulated in 1st trimester
Up-regulated in 3rd trimester
miR-155 FoxP3 Promotes development of Treg cells in thymus and spleen miR-155 deficient mice [49] Down-regulated (progesterone down-regulates miR-155)
miR-155 Socs1 Promotes Th17 differentiation and IL-17 production BALB/c T cells [60] Down-regulated (progesterone down-regulates miR-155)
miR-17 and 19b miR-19b: PTEN
miR-17: TGFbRII and CREB1
Inhibit iTreg differentiation Mice [51] Some miRNAs of this cluster are up-regulated in normal pregnancy
miR-17 and 19b PTEN, TGFb-RII and TGFb1 Block target mRNA Villous human samples [25] Some miRNAs of this cluster are up-regulated in normal pregnancy
miR-17, 92a Presumed to target multiple signaling molecules Regulate proliferation and apoptosis of Tregs miR-17-92 cluster deficient mice [50] Up-regulated in normal pregnancy
miR-19a HLA-G Down-regulates HLA-G expression BALB/c mice [33] Down-regulated
miR-326 Ets-1 Down-regulates Ets expression and promotes Th17 differentiation Patients with multiple sclerosis and mice with experimental autoimmune encephalomyelitis [58,59] Unknown
Presumed to be down-regulated in normal pregnancy
miR-29a IFN-g mRNA Down-regulates IFN-g in NK, CD4+ an CD8+ cells Mice infected with Listeria monocytogenes and Mycobaterium bovis [29] Up-regulated in normal third trimester placentas
miR-29a p85-ανδχδχ42 Up-regulates p53, promotes apoptosis in p53 independent manner HeLa cells
Porcine model
Human placentas
[7,18,21] Up-regulated in endometrium and trophoblast associated with normal pregnancy
Up-regulated in normal third trimester placentas
miR-125b IRF-4 and BLIMP-1 Affects plasma cell differentiation Pregnant human plasma samples [65] Up-regulated
miR-126 TLR7, 9 and VEGFR2 Survival and function of plasmacytoid dendritic cells
Promotes angiogenesis
Knockout mice [68,69] Present in normal pregnancy
Decreased in idiopathic recurrent pregnancy loss
miR-34a Foxp1 Blocks B cell development C57BL/6 mice, WEHI-231 cells and 70Z/3 cells [66] miRNA-34 family up-regulated in third trimester
Table 2: miRNAs that may affect immune system behavior during pregnancy.