Micropreparative Cell Lysate Fractionation in Studying the Effect of Natural Killer Cells on Phenotype, Migration and Apoptosis of Trophoblast Cells in vitro

Natural killer (NK) cells are a population of innate immunecells that have cytotoxic functions and are involved in protectingthe body from viruses and transformed cells. Placental developmentis largely determined by the interaction of decidual NK cells andtrophoblast cells. During pregnancy, NK cells accumulate aroundtrophoblast cells, while regulating trophoblast proliferation, migrationand invasion through the secretion of cytokines and growth factors.The trophoblast, in turn, secretes chemokines and expresses ligandsfor NK cell adhesion receptors. Thus, functional regulation of trophoblastand NK cells is reciprocal. Despite intensive research, the roleof NK cells and methods for correcting their functional activityin reproduction remain controversial. The aim of this study wasto assess the effect of NK cell lysate protein fractions on thephenotype, migration and apoptosis of trophoblast cells in an invitro model experiment, using a new methodological approach. Chromatographicseparation yielded six fractions with different protein cargoes.It was found that CD105 (endoglin) expression on the surface of JEG-3trophoblast cells after their cultivation in the presence of high-(< 250 kDa) or low-molecular-weight (< 45 kDa) fractions ofNK-92 whole-cell lysate was reduced compared to spontaneous expression,with the relative count of trophoblast cells with a CD105+ phenotypebeing also lowered. In addition, one of the low-molecular-weightfractions decreased TRAIL-R2 receptor expression by trophoblastcells. The high-molecular-weight fractions did not enable trophoblastcells to migrate completely through a semi-permeable membrane, withthe area occupied by the migrated cells not exceeding the baselinecontrol area. Moreover, the high-molecular-weight fraction containingthe TGFβ dimer increased p-SMAD2/3 level in trophoblast cells 1h after co-culture, followed by a decrease in the level of thisphosphorylated form after 2 or more hours, and also elevated procaspase-3level one day after co-culture. The data obtained hypotheticallyreflect the possible behavior of chorion cells under the influenceof collapsing NK cells in the event of their death under both normaland pathological conditions caused by viral and bacterial infections,as well as other stress factors leading to reproductive pathology.