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Cytotoxic activity of NK cells in peripheral blood mononuclear cell fraction towards trophoblast cells. o p<0.001 in comparison with background trophoblast cell death; *p<0.001 in comparison with incubation without IL-2; x p<0.001 in comparison with cells from fertile nonpregnant women under similar culturing conditions; + p<0.001 in comparison with cells from nonpregnant women under similar culturing conditions.
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We evaluated cytotoxic activity of peripheral blood NK cells towards trophoblast cells. NK cells either isolated or in the composition of mononuclear cell fraction, caused death of trophoblast cells. In women with physiological pregnancy, the cytotoxic effect of NK cells present in mononuclear cell fraction preincubated with IL-2 was lower than in...
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Context 1
... but also modulates their functional state. We found that in women with physi- ological pregnancy, the cytotoxic effect of NK cells in mononuclear cell fraction preincubated with IL-2 on trophoblast cells was less pronounced than in healthy nonpregnant women without previous pregnancies and healthy fertile women under similar culture condi- tions (Fig. 3). According to published reports [27], NK cells express receptors ILT and KIR2DL4 that bind HLA-G locus molecules expressed by trophoblast cells, thereby inhibiting activation of the cytotoxic function of NK cells. The established differences in the cytotoxic activity of NK cells in the presence of IL-2 in nonpregnant and pregnant women ...
Citations
... ZIKV infection causes endoplasmic reticulum stress in trophoblasts, leading to down-regulation of HLA-C and HLA-G [56]. A series of studies by Mikhailova et al. on the cytotoxicity of IL-2 stimulated NK cells (in PBMC suspension) against JEG-3 trophoblast cells showed that it was weaker in pregnant compared to non-pregnant women [57]. Importantly, like the other cytotoxic cells at the MFI (uNK cells and CD8 T cells), γδT cells did not show cytotoxic activity against the trophoblast cells. ...
Maternal–fetal tolerance mechanisms are crucial during human pregnancy to prevent the immune rejection of the embryo. A well-known mechanism blocking NK-cell cytotoxicity is the interaction of their inhibitory killer-cell immunoglobulin-like receptors (iKIR) with HLA-C molecules on the target cells. In this study, we aimed to investigate the expression of iKIRs (KIR2DL1 and KIR2DL2/3) on the matched decidual and peripheral γδT cells and the localization of HLA-C ligands throughout human pregnancy. The degranulation of γδT cells of pregnant and non-pregnant women in the presence of trophoblast cells was evaluated as well. Our results showed a higher proportion of iKIR-positive γδT cells at the maternal–fetal interface early in human pregnancy compared to the paired blood of pregnant women and full-term pregnancy decidua. In accordance, HLA-C was intensively expressed by the intermediate cytotrophoblasts and decidua-invading extravillous trophoblasts (EVTs) in early but not late pregnancy. Decidual γδT cells during early pregnancy showed higher spontaneous degranulation compared to their blood pairs, but neither decidual nor peripheral γδ T cells increased their degranulation in the presence of Sw71 EVT-like cells. The latter were unable to suppress the higher cytotoxicity of γδT cells, suggesting a complex regulatory landscape beyond NK-like activity inhibition.
... В условиях контактного взаимодействия NK-клетки обладают прямым цитотоксическим действием в отношении клеток трофобласта [7]. Причем их цитотоксичность зависит от того, находятся они в составе фракции мононуклеаров или выделены из нее как самостоятельная популяция, а также от наличия в прошлом или настоящем у женщины беременности [8]. NK-клетки по-разному управляют ангиогенезом в совместной культуре эндотелиальных клеток и клеток трофобласта в случае их дистантного и контактного сокультивирования [9]. ...
Placenta development is largely determined by the interaction of natural killer (NK) cells and trophoblast cells. Despite intensive research, the role of NK cells and methods for correcting their functional activity in reproduction remain controversial. The aim of this study was to investigate the effect of protein fractions of NK cell lysate on trophoblast cell proliferation in a model experiment in vitro. Chromatographic separation resulted in obtaining six cell lysate fractions with different sets of proteins (25–250 kDa). It was found that all the studied fractions stimulated trophoblast cell proliferation. Proliferation markers such as protein kinase B (AKT/ PKB) and extracellular signal-regulated kinases (ERK1/2) were found in the protein fractions with molecular weights of 36–250 kDa, 29–66 kDa, and 47–62 kDa. The obtained data on the change in the proliferative activity of JEG-3 cells under the influence of the NK-92 cell lysate fractions hypothetically reflect the behavior of chorionic cells surrounded by NK cells in the event of their death under normal or pathological conditions caused by viral and bacterial infections, as well as other stress factors that lead to reproductive pathology.
... These differences may also be associated with the influence of monocytes on the phenotype of NK cells in PBMCs. This assumption is consistent with the previously established differences in the cytotoxicity of NK cells in PBMCs and NK cells isolated from PBMC fractions [55]. It should be noted that a decrease in the expression of receptors by pNK cells in the presence of TGFβ affected not only the activation receptors but also an inhibitory receptor-KIR2DL1. ...
During pregnancy, uterine NK cells interact with trophoblast cells. In addition to contact interactions, uterine NK cells are influenced by cytokines, which are secreted by the cells of the decidua microenvironment. Cytokines can affect the phenotypic characteristics of NK cells and change their functional activity. An imbalance of pro- and anti-inflammatory signals can lead to the development of reproductive pathology. The aim of this study was to assess the effects of cytokines on NK cells in the presence of trophoblast cells in an in vitro model. We used TNFα, IFNγ, TGFβ and IL-10; the NK-92 cell line; and peripheral blood NK cells (pNKs) from healthy, non-pregnant women. For trophoblast cells, the JEG-3 cell line was used. In the monoculture of NK-92 cells, TNFα caused a decrease in CD56 expression. In the coculture of NK cells with JEG-3 cells, TNFα increased the expression of NKG2C and NKG2A by NK-92 cells. Under the influence of TGFβ, the expression of CD56 increased and the expression of NKp30 decreased in the monoculture. After the preliminary cultivation of NK-92 cells in the presence of TGFβ, their cytotoxicity increased. In the case of adding TGFβ to the PBMC culture, as well as coculturing PBMCs and JEG-3 cells, the expression of CD56 and NKp44 by pNK cells was reduced. The differences in the effects of TGFβ in the model using NK-92 cells and pNK cells may be associated with the possible influence of monocytes or other lymphoid cells from the mononuclear fraction.
... Prior literature showed that peripheral blood NK cells activated by phorbol myristate acetate (PMA) have reduced IFNγ production in pregnant women compared with women in the proliferative phase of the menstrual cycle (Veenstra van Nieuwenhoven et al., 2002). We established previously that the cytotoxic activity of peripheral blood NK cells towards trophoblast cells of the JEG-3 cell line in vitro was reduced in pregnant women compared with nonpregnant women (Mikhailova et al., 2019). Higuma-Myojo and co-authors established that the number of peripheral blood NK cells producing IL-10 increased in women in the first trimester of pregnancy compared with non-pregnant women (Higuma-Myojo et al., 2005). ...
Background
Maternal natural killer cells (NK cells) are a prevailing leukocyte population in the uteroplacental bed. The contact interaction and/or cytokine production of these cells controls trophoblast differentiation, migration and invasion.
Objective
To assess the impact of supernatants obtained during culturing of placentas from the first and third trimesters of healthy pregnancies on phenotype of trophoblast and NK cells and impact on adhesion and transmigration of NK cells through trophoblast cell layer.
Results
We established that supernatants obtained from first trimester placentas increased the intensity of CD106, CD49e, CD95, CD49a, CD31, CD51/61, integrin β6, CD29 and VE-cadherin expression by trophoblast cells. The presence of supernatants obtained from the third trimester placentas resulted in increased intensity of CD106, CD51/61, CD49e, CD95, CD49a, CD31 and integrin β6 expression by trophoblast cells. Supernatants obtained from the first trimester placentas increased the intensity of CD11a, CD29, CD49d, CD58, KIR2DL3, CD119 and CD29 expression by NK cells. The presence of supernatants obtained from the third trimester placentas resulted in more intense KIR2DL3, CD119, CD29, CD49d, CD11a, CD29, CD49d and CD58 expression by NK cells. Migration of NK cells through trophoblast cells in the presence of first trimester placental supernatants was increased compared with the migration level in the presence of third trimester placental supernatants. This may be associated with increased expression of CD18 by NK cells.
Conclusion
Secretory products of the placenta increase receptor expression to ensure trophoblast adhesion to the matrix and increase the already sufficiently strong adhesion and migration potential of NK cells.
... Prior literature showed that peripheral blood NK cells activated by phorbol myristate acetate (PMA) have reduced IFNγ production in pregnant women compared with women in the proliferative phase of the menstrual cycle (Veenstra van Nieuwenhoven et al., 2002). We established previously that the cytotoxic activity of peripheral blood NK cells towards trophoblast cells of the JEG-3 cell line in vitro was reduced in pregnant women compared with nonpregnant women (Mikhailova et al., 2019). Higuma-Myojo and co-authors established that the number of peripheral blood NK cells producing IL-10 increased in women in the first trimester of pregnancy compared with non-pregnant women (Higuma-Myojo et al., 2005). ...
Natural killer (NK) cells are the main population of leukocytes in decidua during the first trimester of pregnancy. NK cells can have contact with trophoblast cells during pregnancy, which raises the possibility of mutual influence. This research aimed to evaluate the proliferation and phenotype of peripheral blood NK cells in the presence of trophoblast cells of the JEG-3 cell line. We showed that trophoblast cells of the JEG-3 cell line (American Type Culture Collection (ATCC), USA) produced TGFβ. However, co-culturing of NK and trophoblast cells did not change the SMAD2/3 to pSMAD2/3 ratio within NK cells. These data indicate that the canonical signaling pathway from TGFβ is not activated, but do not preclude activation of SMAD-independent signaling pathways through the effect of TGFβ and/or other cytokines. We established that trophoblast cells inhibited both constitutive and IL-2-induced expression of Ki-67 proliferation marker by NK cells in vitro in both pregnant and non-pregnant women. Constitutive and induced Ki-67 expression by peripheral blood NK cells was increased in pregnant women compared with non-pregnant women. The influence of trophoblast cells on Ki-67 expression by NK cells was more pronounced in the presence of other mononuclear cells than in their absence. In the presence of trophoblast cells and IL-2, the number of NK cells with the CD16+CD57- phenotype in peripheral blood mononuclear cells (PBMCs) was increased in pregnant and non-pregnant women, compared with culturing with IL-2 only. This might reflect a decrease in the number of NK cells at the terminal stage of differentiation. We also revealed the increased content of NK cells with the CD16-CD56bright phenotype in PBMCs of pregnant women when incubated with trophoblast cells and IL-2, compared with culturing with trophoblast cells only. Our results suggest that NK cells need contact interactions with trophoblast cells and additional cytokine stimulation (IL-2, cytokines of other mononuclear cells) to acquire the CD56bright phenotype.
... It can also activate caspases via mitochondrial pathway by stimulating the release of cytochrome c and other apoptogenic molecules to the cytoplasm with sub sequent activation of caspase 9 and then caspase 3 [56]. Nevertheless, the observed markers of apoptosis in the trophoblasts in the presence of NK cells require detailed investigation because trophoblasts have a mechanism protecting them from NK cells that involves expression of HLA G and HLA E [57]. Trophoblasts also express death receptor ligand both on the surface and in soluble form [1]. Besides, it should be taken into account that NK 92 cells used in this in vitro model differ from pNK or dNK cells. ...
Studies of interactions between natural killer (NK) cells and trophoblasts and identification of conditions for the NK cells to perform their cytotoxic function are of fundamental and practical importance for understanding their role in the development of pathological processes and complications during pregnancy. In this study, we examined changes in the content of caspases and studied activation of these enzymes in Jeg-3 trophoblasts in various models of their coculturing with NK-92 cells and demonstrated the necessity of direct contact between these cell populations for the activation of caspase-8 and caspase-3 in the trophoblasts. Contact coculturing of the two cell lines resulted in the appearance of the cytotoxic protein granzyme B in Jeg-3 cells that was accompanied by a decrease in the content of this enzyme in NK-92 cells. Distant coculturing of NK-92 and Jeg-3 cells did not trigger initiator and effector caspases characteristic for the apoptosis development in Jeg-3 cells. The observed decrease in the content of procaspases in the trophoblasts may be associated with alternative non-apoptotic functions of these enzymes.
