We studied changes in angiogenesis during contact interaction of natural killer cells and endothelial cells in the presence of secretory products of trophoblast cells activated by various cytokines. Activated trophoblast regulates angiogenesis by producing soluble factors that affect endothelial cells either directly or indirectly through activation of proangiogenic activity of natural killer cells. A stimulating effect of the trophoblast supernatants activated by IL-1β and an inhibitory effect of trophoblast supernatants activated by IL-6 and TGFβ for the formation of tube-like structures by endothelial cells were revealed. During contact culturing, natural killer cells increased the length of tube-like structures formed by endothelial cells. The trophoblast activated by IL-1β affects angiogenesis both directly through the production of proangiogenic factors and indirectly through activation of the proangiogenic potential of natural killer cells. Trophoblast activated by IFNγ affects angiogenesis only by stimulating the proangiogenic potential of natural killer cells. Under conditions of contact interaction of natural killer cells and endothelial cells, soluble factors of trophoblast activated by IL-6 or TGFβ attenuated the angiogenesis-stimulating effect of natural killer cells.

At the present time, a broad spectrum of CD8+ T lymphocyte subsets is revealed, including naïve cells, memory cells and regulatory subpopulations. Along with cells with high cytolytic activity, some subsets with marked regulatory activity were found there. Each subpopulation is characterized by a set of produced mediators, surface and intracellular markers allowing to suggest their differential in vivo functional activity. The present review article proposes a classification of CD8+ Т cells which takes into account their morphological and functional features. According to conventional view, the CD8+ Т lymphocytes is a cell population exhibiting high cytotoxic ability which is of critical significance in pregnancy, under the conditions of semi-allogenic fetal cell invasion into the endometrium. The fraction of CD8+ T cells is rather high in decidual structures. The review discusses the known mechanisms of differentiation regulation, selective migration and activity of CD8+ T cells in decidual membrane and placenta in the course of pregnancy. Perforine and granzyme are the main cytotoxicity factors of CD8+ Т cells. IL-2, IL-5, IL-13, IFNγ, IL-17, TGF-β and IL-10 cytokines are considered regulatory mediators of CD8+ cells. To induce the effector properties of CD8+ T cells, an antigenic stimulation is required, which is provided by interactions between the CD8+ Т cells and activated CD4+ Т cells or dendritic cells, cytokine effects. Specific differentiation of the CD8+ T cells is determined by differences in microenvironvent. In the course of pregnancy, accumulation of CD8+ Т cells is observed in decidual membrane, but their phenotype and functional properties differ from CD8+ Т cells in peripheral blood. At present time, the mechanisms of selective CD8+ T cell migration to decidual membrane are studied. These events are suggested to be mediated by means of CXCR3 and CCR5 chemokine receptors, IL-6 and IL-15 cytokines. The features of CD8+ Т cell activities, and production of some cytokines, e.g., CSF2, IFNγ, IL-1β, IL-2, IL-6, IL-8,IL-10, IL-12 and TNFα in decidual membrane and is of critical significance for effective invasion of trophoblast cells. In turn, the trophoblast and placental cells promote development of regulatory CD8+ Т lymphocytes in decidual membrane, being able to induce CD8+ T cell apoptosis in decidual membrane. Hence, interaction between the maternal CD8+ T cells and trophoblast in the area of uterine-placental contact is an important link during development of immunological tolerance in the maternal/fetal system.

Despite ample data on cytokine secretion in the uteroplacental interface, the influence of microenvironment cells, in particular, trophoblast cells on angiogenesis and the role of cytokines in this process remain poorly studied. We studied the influence of cytokines on the formation of tube-like structures by endothelial cells in the presence of trophoblast cells and showed that trophoblast cells suppressed the angiogenic potential of endothelial cells. Antiangiogenic cytokines IFN-γ, IL-10, TNF-α, and TGFβ via modulation of trophoblast cells stimulated the formation of tube-like structures by endothelial cells. In the co-culture of endothelial and trophoblast cells, the effects of cytokines changed and they gained additional regulatory functions.

We studied the effects of secretory products of the placenta obtained from women with normal pregnancy and preeclampsia on the expression of surface markers by THP-1 cells cultured on a 3D Matrigel scaffold. Secretory products of third trimester placentas obtained from women with normal pregnancy reduced the relative number of THP-1 cells expressing CD54 and CD14 molecules and expression of CD14 and CD95 molecules by THP-1 cells in comparison with the effect of secretory products first trimester placentas. In parallel, the intensity of CD49d expression by THP-1 cells increased in the presence of secretory products of third trimester placentas in comparison with the first trimester. No differences in the expression of the studied molecules by THP-1 cells under the effect of placentas from women with physiological pregnancy and patients with preeclampsia were found.

An important role in the formation of immunological tolerance during pregnancy play T lymphocytes. In the present review discusses the characteristics of T lymphocytes, decidua and placenta, especially their migration and functional activity during pregnancy. The review discusses the role of the subpopulations of Th1, Th17, Th2 and Treg lymphocytes in the formation of the placenta and the immune regulation of pregnancy, as well as their interaction with the cells of the decidua and trophoblast.

The interaction of endothelial cells with cells of the microenvironment, including monocytes/ macrophages, and extracellular matrix during angiogenesis is controlled by cytokines. The stimulating effect bFGF, IL-8, and VEGF on the formation of capillary-like structures by endothelial cells was demonstrated in both monoculture and in co-culture with THP-1 cells; in the latter case, the effects of bFGF and VEGF were more pronounced. IL-8 reduced branching of vascular tubes in co-culture in comparison with monoculture of endothelial cells. Placental growth factor PlGF had no effect of tube formation by endothelial cells in monoculture, but in co-culture with THP-1 cells this cytokine in high concentrations exhibited proangiogenic activity. TGFb inhibited the formation of vascular tubes by endothelial cells and its antiangiogenic potential was more pronounced in co-culture with THP-1 cells.

TNFα inhibited proliferation and did not inhibit migration JEG-3 trophoblast cells, IL-1β stimulated both cell proliferation and migration, IL-6 and IL-8 stimulated only cell migration, IFNγ has either stimulating or inhibitory effect on proliferation of trophoblast cells depending on its concentration. Cytokines IL-10 and IL-4 stimulated only migration of trophoblast cells. VEGF, PlGF, and TGFβ stimulated both proliferation and migration, and bFGF only migration of trophoblast cells.

Abstract. During the passage through the utero-placental circulation, peripheral blood monocytes are exposed to action of various soluble placenta-derived factors. Subsequently these cells migrate to placental tissue and play a key role in regulation of placental growth and development. We investigated the influence of placental secretory factors upon expression of THP-1 cells surface receptors during normal pregnancy, and pregnancy complicated with preeclampsia. Soluble placenta-derived factors produced by the third-trimester placenta caused reduced intensity of CD11а, CD18, CD54, CD14, TRAIL and VEGFR1 expression on THP-1 cells, as compared with the first-trimester placental extracts. Soluble placenta-derived factors from preeclamptic placenta caused an increased intensity of CD18 and CD54 expression by THP-1 cells and decreased intensity of VEGFR1 expression in comparison to normal pregnancy. The work was supported by grants of the President of the Russian Federation № НШ-131.2012.7, СП-3492.2013.4 МК-1580.2013.7 and by grant РФФИ № 13-04-00304 А.

Abstract. Placental cell populations produce a great variety of angiogenic factors and cytokines than control angiogenesis in placenta. Functional regulation of endothelial cells proceeds via modulation of endothelial cell receptors for endogenous angiogenic and apoptotic signals. Endothelial phenotype alteration during normal pregnancy and in cases of preclampsia is not well understood. The goal of this investigation was to evaluate altered expression of angiogenic and cytokine receptors at EA.hy926 endothelial cells under the influence of placental tissue supernatants. Normal placental tissue supernatants from 1st and 3rd trimesters, and pre-eclamptic placental tissue supernatants (3rd trimester) stimulated angiogenic and cytokine receptors expression by the cultured endothelial cells, as compared with their background expression. Tissue supernatants from placental samples of 3rd trimester caused a decreased expression of angiogenic and cytokine receptors by endothelial cells, thus reflecting maturation of placental vascular system at these terms. Supernatants from preeclamptic placental tissue induced an increase of CD119 expression, in comparison with normal placental supernatants from the 3rd trimester. This finding suggests that IFNγ may be a factor of endothelial activation in pre-eclampsia. The study was supported by grants ГК №02.740.11.0711, НШ-3594.2010.7., and МД-150.2011.7.

Abstract. Leukocyte recruitment to placental tissue is an important factor of its development. In this respect, adhesion molecules at the endothelial cell surface represent a key determining factor of leukocyte adhesion and their trans-endothelial migration. The goal of investigation was to evaluate changed expression of adhesion molecules on the endothelial cells induced by supernates of placental tissue cultures. Placental tissue supernatants produced by the first- and third-trimester placental tissue from normal pregnancy, as well as from women with gestosis, induced higher expression of CD31, CD9, CD62E, CD62P, CD34, CD54, CD51/61, CD49d and integrin β7 expression by endothelial cells, as compared with their baseline levels. However, the supernates from pre-eclamptic placental tissue (3rd trimester) caused an increased CD9 expression by endothelial cells, as compared with effects of placental supernates from eclampsia-free cases. Our data contribute to understanding a possible role of endothelial cell adhesion molecules in recruitment of leukocytes to placental tissue and possible participation of adhesion molecules in pathogenesis of pre-eclampsia. The work was supported by a grant from Russian Ministry of Education and Science ГК №02.740.11.0711 and Presidential grant № НШ-3594.2010.7 and МД-150.2011.7. (Med. Immunol., 2011, vol. 13, N 6, pp 589-596)

Decidual and placental macrophage pools are renewed due to its transendothelial monocyte migration from peripheral blood. Tissue macrophages control placental development and provide fetomaternal immunological tolerance. Preeclamptic pregnancy is accompanied by increased monocyte migration to decidual tissue and local inflammatory events. Regulatory mechanisms of monocyte recruitment to placental and decidual tissues is still unclear. Therefore we investigated the influence soluble placental factors (SPFs) during the first- and third-trimester normal pregnancy, as compared to effects of these factors in preeclamptic pregnancy. We studied biological actions of SPF upon transendothelial migration of monocyte-like THP-1 cells and their phenotypic pattern. Transendothelial migration of THP-1 cells was more intensive with firsttrimester SPFs from normal pregnancy, when compared with third-trimester samples, and it was accompanied by decreased CD11a expression. SPFs from pre-eclamptic pregnancy caused an increase in transendothelial migration of THP-1 cells, as compared to SPFs from normal pregnancies, being accompanied by increased CD11b expression. The present study was supported by grants ГК № 02.740.11.0711, НШ-3594.2010.7, МД-150.2011.7 and a grant from St.-Petersburg Goverment for young scientists.

We studied the influence of factors secreted by the placenta in physiological and preeclampsia-complicated pregnancy on migration activity of endothelial EA.Hy926 cells. It was found that migration of endothelial cells was more intensive in the presence of secretory factors from trimester I placentas in comparison with trimester III placentas and was lower in the presence of placental factors in preeclampsia in comparison with physiological pregnancy.

The formation of vascular tubules by EA.Hy926 endothelial cells was studied in the presence of placental secretory products from women with normal gestation at early and late periods and with gestosis. The factors secreted by placental tissues at the early stages of placental development stimulated the branching angiogenesis, while the products of the end of pregnancy stimulated nonbranching angiogenesis. In gestosis the placental tissue secreted products stimulating even more intense nonbranching angiogenesis, which manifested by a lesser number of branchings of vascular tubes formed by EA.Hy926 endothelial cells.

We studied the effects of soluble products of the placental tissue from women with normal pregnancy and gestosis on the cytokine secretion by endothelial EA.Hy926 cells. The secretory products of the placental tissue induced the production of angiogenin, bFGF, IL-8, MCP-1, and RANTES by endothelial cells. The secretion of bFGF by EA.Hy926 cells increased, while IL-8 secretion decreased under the effects of factors produced by the placental tissue in gestosis but not in normal pregnancy. This could be aimed at reduction of inflammation intensity in the placental tissue and maintenance of endothelial and trophoblast cells viability.

In the present review modern data about change of morfo-functional properties of a trophoblast during pregnancy, and also about influence of the cytokines produced by cells of a microenvironment, including leucocytes of mother, on a functional state of trophoblast is cited. Features of interaction between trophoblast and immune cells of mother are described within physiological pregnancy and within pregnancy complicated by preeclampsia.

The localization of apoptosis and expression of proapoptotic and antiapoptotic factors by the placental tissue were compared during normal pregnancy and gestosis-complicated pregnancy. The degree of apoptosis did not differ in the third trimester of normal pregnancy and gestosis-complicated pregnancy. Increased expression of Fas, caspase-8, and caspase-3 in placental tissue during normal pregnancy was shown to contribute to the suppression of angiogenesis and growth of placental tissue. No differences were found in the expression of FasL (CD95L), caspase-2, caspase-9, and Mcl-1 by placental cells during normal pregnancy and gestosis-complicated pregnancy. Increased expression of TRAIL by trophoblast cells is a protective mechanism from apoptotic signals of maternal cytotoxic lymphocytes and NK cells during gestosis.

Vascular endothelial growth factors VEGF-A and VEGF-C are the main angiogenic factors that control growth of new blood and lymphatic vessels in the organism, and they also possess several immunoregulatory activities. Expression of VEGF-A and VEGF-C mRNA as well as mRNA for VEGF receptors in lymphocytes and macrophages of naive mice was investigated. Using reverse transcription and subsequent polymerase chain reaction, we found that peritoneal macrophages, thymocytes, and lymph node cells constitutively expressed VEGF-A and VEGF-C mRNA. In addition, macrophages were positive for VEGFR-1, VEGFR-2, VEGFR-3, NRP-1, and NRP-2 mRNA, whereas thymocytes and lymph node cells expressed mRNA of the same receptors except VEGFR-1. These data expand our knowledge concerning gene distribution of VEGF receptors in the organism, in particular, among the cells of the immune system. This suggests that, along with their major angiogenic properties, VEGF family members additionally might also perform important mediatory functions within the immune system.