The beta-galactoside-binding proteins galectin-1 and -3 are thought to modulate cell-extracellular matrix interactions in cell adhesion and migration. In this study, their occurrence in human trophoblast has been investigated. In the first trimester placenta galectin-1 is expressed in the cytotrophoblast of the mid and distal cell columns, but absent from the villous and proximal column cytotrophoblast. The villous syncytiotrophoblast was also positive. Galectin-3, on the other hand, was uniformly localized in the villous cytotrophoblast and mid and distal cell columns. Immunolocalization of these proteins in placental bed tissue has shown that galectin-1 and -3 are not present in cytokeratin-positive interstitially migrating cytotrophoblast. The co-localization of galectin-1 with extracellular laminin in cultures of cytotrophoblast, choriocarcinoma or decidual stromal cells is consistent with a role in the organization of extracellular matrix and the regulation of cell motility.

Despite numerous studies, isolating pure preparations of extracellular vesicles (EVs) has proven challenging. Here, we compared ion-exchange chromatography (IEC) to the widely used sucrose density gradient (SDG) centrifugation method for the purification of EVs. EVs in bulk were isolated from pooled normal human amniotic fluid (AF) by differential centrifugation followed by IEC or sucrose density gradient separation. The purity of the isolated EVs was evaluated by electrophoresis and lectin blotting/immuno blotting to monitor the distribution of total proteins, different EVs markers, and selected N-glycans. Our data showed efficient separation of negatively charged EVs from other differently charged molecules, while comparative profiling of EVs using SDG centrifugation confirmed anion-exchange chromatography is advantageous for EV purification. Finally, although this IEC-based method was validated using AF, the approach should be readily applicable to isolation of EVs from other sources as well.

Urine is a readily available source of relatively large quantities of extracellular vesicles (EVs). However, the isolation of urinary EVs (uEVs) is complicated by the presence of Tamm-Horsfall protein (THP), which polymerizes and co-precipitates as a contaminant. This may make glycan analysis of uEVs difficult since THP is heavily glycosylated. To facilitate glycosylation analysis and address the need for elimination of non-uEV glycans, we present a modification of the uEV isolation procedure and use the isolated uEVs in the development of a lectin-exosome binding assay. Salt precipitation was employed to remove THP under conditions originally described for its separation from urine, followed by differential centrifugation. The quality of the isolated uEVs was examined by electron microscopy, SDS-PAGE, and immunoblotting. The uEVs were subsequently immobilized on solid phase and probed with labeled plant lectins using the lectin-exosome binding assay. Our results indicate that the isolated uEVs had preserved structural integrity and reacted with labeled plant lectins in a selective, carbohydrate-dependent manner. The basic lectin binding pattern of uEVs obtained by our method can be used as a reference for assessing the composition of their surface glycans in different physiological and pathological conditions.

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The assessment of the carbohydrate composition of N- and O-glycans of pregnancy-associated CA125 was in general agreement with available data on CA125 of cancer origin. The main difference was observed in reactivity to Canavalia ensiformis agglutinin (ConA) and Phaseolus vulgaris erythroagglutinin (PHA-E) binding.