title: Galectin-1 binds mucin in human trophoblast.
abstract: Mucins are multifunctional highly glycosylated proteins expressed by the female reproductive tract. Differential expression of MUC1 and MUC15 has been shown in trophoblast. This study was undertaken to establish the distribution of mucin(s) in cytotrophoblast cell cultures using anti-bovine submaxillary mucin (BSM) and to investigate the possibility of MUC1/mucin(s) being a binding partner of trophoblast galectin-1. MUC1 is demonstrated here using immunocytochemistry on isolated cytotrophoblast and the HTR-8/SVneo extravillous trophoblast cell line but detection of additional trophoblast mucins cannot be excluded. Western blot analysis showed similar bands ranging from 30 to >200 kDa with anti-BSM and the well-known mucin antibodies HMFG1 and B72.3. Immunocytochemistry and cell-based ELISA data were found to support that all of the antibodies used are reactive with BSM, suggesting the presence of shared epitopes between BSM and trophoblast mucin(s). Binding of galectin-1 to trophoblast MUC1/mucin(s) was analyzed using a solid-phase assay and co-immunoprecipitation. Recombinant galectin-1 binding to isolated trophoblast mucin in solid-phase assay was sensitive to lactose, a carbohydrate inhibitor of galectin binding. In whole HTR-8/SVneo lysates, ~200 kDa mucin was detected in galectin-1 immunoprecipitates, while endogenous galectin-1 was present in BSM-immunoprecipitates. Furthermore, double fluorescence immunocytochemistry showed overlap of galectin-1 and trophoblast mucins at the plasma membrane of HTR-8/SVneo cells. These results suggest that trophoblast mucin(s) could act as binding partners of galectin-1, in a carbohydrate-dependent manner.
authors.affiliation: Institute for the Application of Nuclear Energy, INEP, University of Belgrade, Belgrade, Serbia, zana@inep.co.rs.
authors.forename: Zanka
authors.initials: Z
authors.lastname: Bojić-Trbojević
authors.forename: Milica
authors.initials: M
authors.lastname: Jovanović Krivokuća
authors.forename: Nikola
authors.initials: N
authors.lastname: Kolundžić
authors.forename: Miloš
authors.initials: M
authors.lastname: Petronijević
authors.forename: Svetlana
authors.initials: S
authors.lastname: Vrzić-Petronijević
authors.forename: Snežana
authors.initials: S
authors.lastname: Golubović
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Vićovac
mesh_terms: D002478:Cells, Cultured; D037483:Galectin 1 / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D009077:Mucins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*
chemical_list: D037483:Galectin 1; D009077:Mucins