Deletion Of Prl7d1 Causes Placental Defects At Mid-Pregnancy In Mice

Objective:Prolactin family 7,subfamily d,member 1(Prl7d1),a member of the expanding prolactin family,is expressed in the placenta with peak expression observed at 12 days post coitum(dpc)in mice.Previous studies have shown that Prl7d1 is a key mediator of angiogenesis in vitro;however,its physiological roles in placental development in vivo have not been characterized.In the present study,we aimed to generate Prl7d1 KO C57/BL6 mice and investigate its function during mid-gestation,which could help us to elucidate the molecular mechanisms underlying normal and pathological pregnancies.Methods:1.Prl7d1 KO C57/BL6 mice were generated by TALEN technology,and mutations were identified by DNA sequencing.Multiplex PCR amplification was performed to identify female and male placenta.2.Western blotting and immunohistochemical staining were performed to investigate the expression of PRL7D1 in placenta.3.HE,periodic acid Schiff’s(PAS),Masson and immunohistochemical staining were used to observe the morphological changes of placenta.4.Placenta samples were collected at 12.5 dpc,RNA sequencing(RNA-Seq)was performed to analyze the downstream pathways of Prl7d1 signaling responsible for the altered reproductive phenotype in Prl7d1-deficient mice.Results:1.PRL7D1 protein was highly expressed in the junction zone of the placenta of WT mice,whereas it was not detected in KO placentas.2.Maternal Prl7d1 KO reduces litter sizes and the number of surviving embryos at 12.5 dpc.3.Prl7d1 KO causes placental defects.We demonstrated that its absence results in striking placental abnormalities at 12.5 dpc,including a reduction in the proportion of labyrinth layers and a significant increase in decidual NK cells,glycogen trophoblasts,and trophoblast giant cells in the junctional zone.Moreover,placentas from Prl7d1-null mice displayed a thickened decidual spiral artery.Notably,these negative effects were more pronounced in male fetuses.4.There was little change in gene expression profiles between female and male placentas from WT mice.In contrast,an increased number of differentially regulated genes was observed between other groups(Prl7d1KO male versus Prl7d1 KO female,Prl7d1 KO male versus WT male,and Prl7d1 KO female versus WT female).Prl7d1 deficiency leads to disorders in multiple signaling pathways,and in turn,might result in placental structural defects.Conclusion:In conclusion,our study demonstrates that Prl7d1 is crucial for placental development.Prl7d1 deficiency leads to disorders in multiple signaling pathways,and in turn,might result in placental structural defects.Moreover,significant differences in placental phenotypes and gene expression profiles,depending on the sex of the fetus,were observed.Overall,this study provides valuable insights into the developmental events that occur during mid-gestation,and could help us to elucidate the molecular mechanisms underlying normal and pathological pregnancies.