The Role Of Inhibitors Of Differentiation 3(Id3) And Its Related Regulatory Factors In Embryo Implantation

Embryo implantation,from fertilization to blastocyst implantation,which is a series of cellular and molecular biological events.It is an extremely complex physiological process,including the location,adherence and invasion of free blastocysts,and placental formation.It is a continuous dynamic biology phenomenon.If defect in these processes will result in poor pregnancy ending.Endometrial decidualization is a special tissue in which endometrial stromal cells are stimulated,proliferated and differentiated by decidualization-inducing factors after embryo adhesion.Studies have shown that about 20% of pregnancy failures are associated with abnormal stromal cell decidualization.Decidualization was regulated by series of signaling pathways and genes.The inhibitors of differentiation 3(Id3),serves as a transcription factor of cells,which has the function in inhibiting differentiation and promoting proliferation.Our previous data showed that Id3 was strongly expressed in the control compared to the artificially induced decidual tissue,suggesting that there was an important role of decrease Id3 gene expression in decidualization.Positive regulatory domain zinc finger protein 1(Prdm1),is known to interact with Id3,which plays a key role in the differentiation of various cells.However,the function of Id3 or its interaction with Prdm1 in decidualizaiton is unclear.This study explored the expression of Id3 and Prdm1 in the endometrium of mice early pregnancy and artificially induced decidualization model.Especially,we explored the role of Id3 and Prdm1-Id3 signalingin decidualization.To clarify its effect during implantation and decidualization.The main results are as follows: 1.Expression patterns of Id3 in early pregnancy modelImmunohistochemistry,in situ hybridization,Western blot and RT-q PCR were used to detect the expression of Id3 in early pregnancy mouse model.The results showed that Id3 was highly expressed in the formation phase of endometrial receptivity(the fourth day of pregnancy),and was lower expressed in the decidualized uterus.Moreover,the expression of Id3 in inter-implantation sites(IIS)of D5 and D6 was significantly higher than that in implantation sites(IS).The expression pattern of Id3 in pseudo-pregnant mouse model endometrium was similar to that of normal early pregnancy,which suggested that expression Id3 in mouse early preanancy enddometeiumd does not regulated embryonic signal.In mice artificially induced decidualized model,Id3 was low expressed in artificially induced decidualized endometrium,which suggesting that down-regulation of Id3 was associated with decidualization.Those results implied that Id3 may be involved in the decidulization.2.Id3 regulates decidualization of endometrial stromal cellsAfter isolating mice endometrial stromal cells(ESCs),to establish artificially induced decidualization in vitro model.It was found that artificially induced decidualization in vitro can inhibit the expression of Id3.Otherwise,Id3 overexpression can significantly inhibit the stromal cells decidualization.3.Expression patterns of Prdm1 in early pregnancy modelImmunohistochemistry,Western blot and RT-qPCR were employed to determine expression of Prdm1 in the mouseearly pregnancy model.Prdm1 was mainly expressed in glandular and luminal epithelium at D1 and in stromal cells at D4.After implantation,Prdm1 was mainly expressed in the primary decidual zone(PDZ)in D5 and the secondary decidual zone(SDZ)in D6 or D8.Importantly,the expression of Prdm1 in IS was significantly higher than that in IIS at D5 and D6.Moreover,Prdm1 was stronger expressed in D5 and D6 than that in other days.In artificially induced decidualization in vivo mice model,Prdm1 was induced expression,suggesting that up-regulation of Prdm1 is associated with decidualization.These results indicate that Prdm1 may be involved in mice decidualization.4.Prdm1 regulates decidualization of endometrial stromal cellsWith the use of isolating mouse endometrial stromal cells,to establish induced for decidualization in vitro.It was found that the expression of Prdm1 was increased after induced decidualization in vitro,and siPrdm1 could significantly reduce the proliferation and differentiation of stromal cells.In addition,inhibiting Prdm1 expression could promote the up-regulation of Id3 and inhibit the process of decidualizaiton.These results showed that Id3 can inhibit decidualization.If inhibit Prdm1 expression by siRNA interference can up-regulate Id3 and inhibit the decidualization.In summary,Id3 is involved in regulating the endometrial stromal cells decidualization.