The Role Of YPEL3 On The Receptivity Formation Of Goat Endometrial Epithelial Cells

Early pregnancy failure is one of the important reasons leading to the low reproductive rate of livestock and hindering the development of animal husbandry.Successful implantation of embryos requires the establishment of a complex and tight relationship between a well-developed embryo and a receptive endometrium.Abnormal endometrium is the main cause of pregnancy failure.During the process of goat embryo implantation,the endometrium undergoes morphological and functional changes mainly under the action of hormones such as E₂,P₄ and IFN-τ,thus providing the best environment for the implantation of the embryos.Although many cytokines and transcription factors are involved in regulating the function of the endometrium during embryo implantation,the specific regulatory mechanism is still unclear due to its complex regulatory network.YPEL3 is a highly conserved gene among species,and it is currently believed that YPEL3is a tumor suppressor.Transcriptome sequencing of the endometrium of goat early pregnancy showed that the expression of YPEL3 was significantly inhibited during the embryo adhesion stage.It is speculated that YPEL3 may be involved in the regulation of endometrial function during the adhesion stage.However,the specific role and regulatory mechanism are still unclear.In this study,the expression of YPEL3 in the goat endometrium in early pregnancy was analyzed by immunohistochemical detection,and the goat endometrial epithelial cells were further treated with E₂,P₄ and IFN-τto simulate the intrauterine hormone environment in the adhesion period,and to construct a endometrial receptivity model.The role of YPEL3in the establishment of endometrial receptivity was studied by Western blot,RT-q PCR,cellular immunofluorescence,lentiviral interference,overexpression vector transfection,CCK-8 and ELISA.The main content is as follows:（1）Immunohistochemical results showed that YPEL3 was mainly localized in the luminal and glandular epithelial cells of goat endometrial,and was weakly expressed in stromal cells.The expression of YPEL3 was lower on the 18th day of goat embryo adhesion period.E₂,P₄and IFN-τcombined treatment of goat endometrial epithelial cells inhibited the expression of YPEL3 at both m RNA and protein levels（p<0.01）.（2）Under the treatment of E₂,P₄ and IFN-τ,overexpression of YPEL3 in goat endometrial epithelial cells can inhibit the expression of Vimentin（p<0.01）,but has no significant effect on the expression of N-cadherin（p>0.05）;meanwhile,it inhibits the expression of ISG15（p<0.01）,but has no significant effect on the expression of RSAD2 and CXCL10（p>0.05）.In the absence of hormone stimulation,interfering with YPEL3 can promote the expression of Vimentin（p<0.01）,but has no significant effect on the expression of N-cadherin（p>0.05）,nor on cell proliferation,while inhibiting the expression of PGFS,PTGES and the secretion of PGF_2α（p<0.01,p<0.001）.（3）Under the treatment of E₂,P₄ and IFN-τ,overexpression of YPEL3 can inhibit the expression ofβ-catenin（p<0.01）,a key protein of Wnt/β-catenin signaling pathway,and inhibit the nuclear translocation ofβ-catenin.Interference with YPEL3 promotesβ-catenin expression（p<0.01）and nuclear translocation ofβ-catenin without hormone stimulation.Pretreatment of goat endometrial epithelial cells overexpressing YPEL3 with theβ-catenin activator CHIR99021 can restore the decreased expression of Vimentin caused by overexpression of YPEL3（p<0.05）.In conclusion,this study found that YPEL3,as a hormone-regulated factor,regulate endometrial receptivity by regulating the Wnt/β-catenin signaling pathway.This provides new ideas for revealing the mechanism of ruminant livestock embryo attachment and improving the pregnancy rate of livestock embryos.