Extracellular presence/release of galectins from HTR-8/SVneo extravillous trophoblast cells*

Abstract

Galectins (gals) are β-galactoside binding lectins, involved in many processes at the fetomaternal interface where they can exert their roles both in and out of cells. The aim of this work was to explore the extracellular presence/release of HTR-8/SVneo extravillous trophoblast cell line galectins. To that end, conditioned medium (CM) from HTR-8/SVneo cell culture was fractionated into a high molecular mass fraction (HMF) and low molecular mass fraction (LMF) using 100 kDa cut-off concentrators. In addition, extracellular vesicles (EVs) were isolated from CM by ultracentrifugation. Size and shape of the EVs were analyzed by transmission electron microscopy and their galectin mRNA content was determined by real-time PCR. The presence of galectins in fractions of HTR-8/SVneo CM and EVs was detected by western blot. All three galectins expressed by HTR-8/SVneo cells (gal-1, gal-3, and gal-8) were detected in the CM, HMF, and EVs, while only gal-1 was found in the LMF. In addition, EVs contained all three galectin mRNAs. These results reveal that free, complexed, and EV-associated forms of galectins were released from extravillous trophoblast cells, suggesting their potential to exert extracellular functions both in their immediate vicinity at the fetomaternal interface and distant locations.

Human trophoblast requires galectin-3 for cell migration and invasion

“…5e,f), thus participating in base line cell invasion. The Matrigel galectin-3 contribution to trophoblast cell invasion shown here is however hard to fully appreciate, since HTR-8/SVneo cells also release galectin-3 into the medium 36 . On the other hand, the presence of galectins in Matrigel could be seen as a factor making this matrix a better model of decidual ECM.…”

“…Based on galectin binding specificity and potentially shared ligands, it was of interest to determine whether galectin-3 participates in processes affecting trophoblast cell migration and cell invasion. Recently, we have shown that trophoblast HTR-8/SVneo cells release galectin-1, -3 and -8 into culture medium 36 . Thus, two approaches were taken, the first one with either increased, or blocked extracellular galectin-3, and the other based on reduction of intracellular galectin-3 by targeting its mRNA.…”