title: Fatty Acid-Binding Protein 4 in Endometrial Epithelium Is Involved in Embryonic Implantation.
abstract: OBJECTIVE
  To clarify the role of fatty acid-binding protein 4 (FABP4) of endometrial epithelial cell in the establishment and maintenance of pregnancy and the involvement in the pathogenesis of pregnancy loss.
  
  
  METHODS
  The expression of FABP4 and uterine receptive factor (LIF, Integrin-β3 and Claudin 4) was determined by Western blotting or quantitative PCR. FABP4 siRNA was used to silence FABP4 while FABP4 inhibitor was used to inhibit the function of FABP4 in endometrial epithelial cell. ICR mice were raised to evaluate the effect of FABP4 silence or inhibition on embryo implantation in vivo after FABP4 siRNA mixture or inhibitor was injected into uterus, and an embryonic adhesion system using trophoblast spheroids mimicking embryos was set up to assess the effect of FABP4 silence or inhibition on embryonic adhesion onto endometrial cell in vitro.
  
  
  RESULTS
  The expression of FABP4 mRNA was significantly decreased in the deciduas of women with pregnancy loss compared with that of women with normal pregnancy. FABP4 siRNA significantly reduced the number of embryos implanted and FABP4 expression in ICR mice. FABP4 inhibition also significantly decreased the number of embryos implanted. Either silence or inhibition of FABP4 in endometrial epithelial cell abolished the expression of uterine receptive factors induced by the combination of estrogen and progesterone-induced, and reduced the number of trophoblast spheroids adhered onto endometrial cell.
  
  
  CONCLUSIONS
  FABP4 regulates embryo implantation via altering uterine receptivity and decreased expression of FABP4 in endometrium may be linked with pregnancy loss, indicating FABP4 has biological role in the establishment and maintenance of pregnancy and subsequently is involved in pathogenesis of pregnancy loss.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Qiuyuan
authors.initials: Q
authors.lastname: Zhu
authors.forename: Huilian
authors.initials: H
authors.lastname: Peng
authors.forename: Mengkai
authors.initials: M
authors.lastname: Du
authors.forename: Minyue
authors.initials: M
authors.lastname: Dong
authors.forename: Hanzhi
authors.initials: H
authors.lastname: Wang
mesh_terms: D000328:Adult; D000818:Animals; D016022:Case-Control Studies; D002448:Cell Adhesion; D062506:Claudin-4 / Q000378:metabolism; D010064:Embryo Implantation; D004717:Endometrium / Q000166:cytology; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology; D050556:Fatty Acid-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D039661:Integrin beta3 / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D023421:Models, Animal; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000378:metabolism; D055815:Young Adult
chemical_list: D062506:Claudin-4; D004967:Estrogens; D050556:Fatty Acid-Binding Proteins; D039661:Integrin beta3; D034741:RNA, Small Interfering; D011374:Progesterone
keywords: Embryonic implantation; Endometrium; Fatty acid binding protein 4; Pregnancy loss; Receptivity