The Functional Study Of Protein Kinase A Potential Substrate DDX5 During The Human Endometrial Stromal Cell Decidualization

The key events of pregnancy include fertilization,embryo implantation,endometrial stromal cell decidualization,placental development,etc.The decidualized stromal cells provide sufficient nutrients for the implanted embryo before the development of mature placenta.In addition,the decidualized stromal cells can protect the embryo from the attack of maternal immune cells.Human endometrial stromal cells(HESCs)have a process of proliferation before decidualization,and then HESCs differentiate into decidual cells under the orchestrating of estrogen and progesterone in vivo.Studies have shown that the cAMP-PKA signaling pathway plays a role in the initiation of decidualization,but it is still unclear which substrates are directly phosphorylated after PKA activation for regulating the decidualization.In order to explore the specific molecular mechanism of cAMP-PKA in the initial stage of decidualization,HESC were utilized under the treatment of decidual cocktail.After 24 hours of decidualization stimulation(cAMP and P4),the potential PKA substrates were enriched with PKA substrate motif specific antibodies,and a variety of proteins in the enriched components were identified by mass spectrometry.In this study,RNA helicase DDX5 was selected as the main research object.After DDX5 was knocked down by siRNA,the proliferation rate of HESCs was significantly lower than that of the control group as revealed by MTS assay.By immunofluorescence,the ratio of Ki67 positive signal decreased significantly after DDX5/17 abrogation by siRNA.This indicated that DDX5/17 knockdown inhibited the proliferation of HESCs.After DDX5/17 knockdown,the results of q-PCR and WB showed that the induction levels of the marker gene PRL and IGFBP1 were significantly reduced in the process of cAMP and P4 induced differentiation.Compared with the control group,the morphological transformation of the stromal cells from fibroid to the epithelial-like appearance was overtly compromised during the decidualization after DDX5/17 knockdown.The preliminary mechanism study found that FOXO1 expression was abnormal at the initial stage of decidualization after DDX5 knockdown,indicating that DDX5 may be involved in the occurrence of decidualization at least by regulating the expression of FOXO1.This study revealed the role of RNA helicase DDX5 in decidualization.