title: Galectin-1 influences trophoblast immune evasion and emerges as a predictive factor for the outcome of pregnancy.
abstract: Galectin-1 (gal-1) is expressed at the feto-maternal interface and plays a role in regulating the maternal immune response against placental alloantigens, contributing to pregnancy maintenance. Both decidua and placenta contribute to gal-1 expression and may be important for the maternal immune regulation. The expression of gal-1 within the placenta is considered relevant to cell-adhesion and invasion of trophoblasts, but the role of gal-1 in the immune evasion machinery exhibited by trophoblast cells remains to be elucidated. In this study, we analyzed gal-1 expression in preimplantation human embryos and first-trimester decidua-placenta specimens and serum gal-1 levels to investigate the physiological role played by this lectin during pregnancy. The effect on human leukocyte antigen G (HLA-G) expression in response to stimulation or silencing of gal-1 was also determined in the human invasive, proliferative extravillous cytotrophoblast 65 (HIPEC65) cell line. Compared with normal pregnant women, circulating gal-1 levels were significantly decreased in patients who subsequently suffered a miscarriage. Human embryos undergoing preimplantation development expressed gal-1 on the trophectoderm and inner cell mass. Furthermore, our in vitro experiments showed that exogenous gal-1 positively regulated the membrane-bound HLA-G isoforms (HLA-G1 and G2) in HIPEC65 cells, whereas endogenous gal-1 also induced expression of the soluble isoforms (HLA-G5 and -G6). Our results suggest that gal-1 plays a key role in pregnancy maternal immune regulation by modulating HLA-G expression on trophoblast cells. Circulating gal-1 levels could serve as a predictive factor for pregnancy success in early human gestation.
authors.affiliation: Charité Center 12 Internal Medicine and Dermatology, Reproductive Medicine Research Group,  Medicine University Berlin, BMFZ, Raum 2.0547, AugustenburgerPlatz 1, D-13353 Berlin,  Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Tirado-González
authors.forename: Nancy
authors.initials: N
authors.lastname: Freitag
authors.forename: Gabriela
authors.initials: G
authors.lastname: Barrientos
authors.forename: Valerie
authors.initials: V
authors.lastname: Shaikly
authors.forename: Olga
authors.initials: O
authors.lastname: Nagaeva
authors.forename: Magnus
authors.initials: M
authors.lastname: Strand
authors.forename: Lennart
authors.initials: L
authors.lastname: Kjellberg
authors.forename: Burghard F
authors.initials: BF
authors.lastname: Klapp
authors.forename: Lucia
authors.initials: L
authors.lastname: Mincheva-Nilsson
authors.forename: Marie
authors.initials: M
authors.lastname: Cohen
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Blois
mesh_terms: D000022:Abortion, Spontaneous / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001755:Blastocyst / Q000276:immunology; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D003656:Decidua / Q000276:immunology* / Q000378:metabolism; D010064:Embryo Implantation / Q000276:immunology; D005260:Female; D037483:Galectin 1 / Q000097:blood / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression / Q000276:immunology; D059951:HLA-G Antigens / Q000097:blood / Q000235:genetics / Q000276:immunology*; D006801:Humans; D057131:Immune Evasion; D007108:Immune Tolerance; D007519:Isoantigens / Q000276:immunology; D010920:Placenta / Q000276:immunology* / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011379:Prognosis; D020033:Protein Isoforms / Q000097:blood / Q000235:genetics / Q000276:immunology; D014327:Trophoblasts / Q000276:immunology* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D037483:Galectin 1; D059951:HLA-G Antigens; D007519:Isoantigens; D020033:Protein Isoforms