Decidual-derived RANKL Facilitates Macrophages Accumulation And Residence At The Maternal-fetal Interface In Human Early Pregnancy

Objective:To study the effect of RANK-RANK on the accumulation and residence of macrophages at the maternal-fetal interface.Method of study:Collected 37 cases(age:28.90±2.87 years;gestational weeks at sampling:7.59±0.63 weeks(mean±SD.))of normal pregnancy due to non-medical reasons and have not taken hormone therapy within six months,the decidual tissue of women who were required to terminate the pregnancy.The Decidual macrophages(dMφs)and Decidual stromal cells(DSCs)were isolated,and the difference in the expression of adhesion molecules(CD29,CD31,CD54,CD62L)between RANK~+and RANK~-dMφs were analyzed by flow cytometry(FCM).Then a co-culture system of dMφs and DSCs was established.FCM was used to analyze the differences in the expression of adhesion molecules in RANK~+dMφs and RANK~-dMφs before and after co-cultivation and in RANK~-dMφs.After the RANKL neutralizing antibody was used to block the interaction of RANKL and RANK in the co-culture system of dMφs and DSCs,the expression of adhesion molecules on RANK~+dMφs after co-culture were analyzed by FCM.Finally,the number of dMφs cells attached to the DSCs was calculated by the adhesion experiment to evaluate the adhesion ability of dMφs.Results:RANK~+dMφs is the main subtype of dMφs at the maternal-fetal interface.The expression of adhesion molecules on the surface of RANK~+dMφs were significantly higher than that of RANK~-dMφs.After co-cultivation with DSCs,the expression of adhesion molecules on dMφs were up-regulated in a RANKL dependent manner.Meanwhile,after co-cultivation,dMφs promoted the release of RANKL from DSCs.Consistently,when the RANKL RANK crosstalk between DSCs and dMφs was blocked in vitro,the expression of adhesion molecules dMφs on the surface of RANK~+dMφs dramatically decreased.Finally,in vitro adhesion experiments,it was found that when RANKL neutralizing antibody was used to block RANKL RANK interaction,the number of dMφs adhered to DSCs remarkably decreased.Conclusion:These results indicated that the interaction of RANKL-RANK up-regulated the expression of adhesion molecules on the surface of dMφs,which contributing to the accumulation and residence of dMφs in human early pregnancy,and played an important role in the pregnancy immune homeostasis at the maternal-fetal interface.